Neuromyelitis optica is an inflammatory demyelinating disease of the central nervous system that differs from multiple sclerosis.Over the past 20 years,the search for biomarke rs for neuromyelitis optica has been ongo...Neuromyelitis optica is an inflammatory demyelinating disease of the central nervous system that differs from multiple sclerosis.Over the past 20 years,the search for biomarke rs for neuromyelitis optica has been ongoing.Here,we used a bibliometric approach to analyze the main research focus in the field of biomarkers for neuromyelitis optica.Research in this area is consistently increasing,with China and the United States leading the way on the number of studies conducted.The Mayo Clinic is a highly reputable institution in the United States,and was identified as the most authoritative institution in this field.Furthermore,Professor Wingerchuk from the Mayo Clinic was the most authoritative expe rt in this field.Keyword analysis revealed that the terms "neuro myelitis optica"(261 times), "multiple sclerosis"(220 times), "neuromyelitis optica spectrum disorder"(132 times), "aquaporin4"(99 times),and "optical neuritis"(87 times) were the most frequently used keywords in literature related to this field.Comprehensive analysis of the classical literature showed that the majority of publications provide conclusive research evidence supporting the use of aquaporin-4-IgG and neuromyelitis optica-IgG to effectively diagnose and differentiate neuromyelitis optica from multiple sclerosis.Furthermore,aquaporin-4-IgG has emerged as a highly specific diagnostic biomarker for neuromyelitis optica spectrum disorder.Myelin oligodendrocyte glycoprotein-IgG is a diagnostic biomarke r for myelin oligodendrocyte glycoprotein antibody-associated disease.Recent biomarkers for neuromyelitis optica in clude cerebrospinal fluid immunological biomarkers such as glial fibrillary acidic protein,serum astrocyte damage biomarkers like FAM19A5,serum albumin,and gammaaminobutyric acid.The latest prospective clinical trials are exploring the potential of these biomarkers.Preliminary results indicate that glial fibrillary acidic protein is emerging as a promising candidate biomarker for neuromyelitis optica spectrum disorder.The ultimate goal of future research is to identify non-invasive biomarkers with high sensitivity,specificity,and safety for the accurate diagnosis of neuro myelitis optica.展开更多
The integrity of retinal ganglion cells is tightly associated with diabetic macular degeneration that leads to damage and death of retinal ganglion cells,affecting vision.The major clinical treatments for diabetic mac...The integrity of retinal ganglion cells is tightly associated with diabetic macular degeneration that leads to damage and death of retinal ganglion cells,affecting vision.The major clinical treatments for diabetic macular edema are anti-vascular endothelial growth factor drugs and laser photocoagulation.However,although the macular thickness can be normalized with each of these two therapies used alone,the vision does not improve in many patients.This might result from the incomplete recovery of retinal ganglion cell injury.Therefore,a prospective,non-randomized,controlled clinical trial was designed to investigate the effect of anti-vascular endothelial growth factor drugs combined with laser photocoagulation on the integrity of retinal ganglion cells in patients with diabetic macular edema and its relationship with vision recovery.In this trial,150 patients with diabetic macular edema will be equally divided into three groups according to therapeutic methods,followed by treatment with anti-vascular endothelial growth factor drugs,laser photocoagulation therapy,and their combination.All patients will be followed up for 12 months.The primary outcome measure is retinal ganglion cell-inner plexiform layer thickness at 12 months after treatment.The secondary outcome measures include retinal ganglion cell-inner plexiform layer thickness before and 1,3,6,and 9 months after treatment,retinal nerve fiber layer thickness,best-corrected visual acuity,macular area thickness,and choroidal thickness before and 1,3,6,9,and 12 months after treatment.Safety measure is the incidence of adverse events at 1,3,6,9,and 12 months after treatment.The study protocol hopes to validate the better efficacy and safety of the combined treatment in patients with diabetic macula compared with the other two monotherapies alone during the 12-month follow-up period.The trial is designed to focus on clarifying the time-effect relationship between imaging measures related to the integrity of retinal ganglion cells and best-corrected visual acuity.The trial protocol was approved by the Medical Ethics Committee of the Affiliated Hospital of Beihua University with approval No.(2023)(26)on April 25,2023,and was registered with the Chinese Clinical Trial Registry(registration number:ChiCTR2300072478,June 14,2023,protocol version:2.0).展开更多
As the proportion of renewable energy infiltrating the power grid increases,suppressing its randomness and volatility,reducing its impact on the safe operation of the power grid,and improving the level of new energy c...As the proportion of renewable energy infiltrating the power grid increases,suppressing its randomness and volatility,reducing its impact on the safe operation of the power grid,and improving the level of new energy consumption are increasingly important.For these purposes,energy storage stations(ESS)are receiving increasing attention.This article discusses the structure,working principle,and control methods of grid-following and grid-forming energy-storage converters,which are currently commonly used.A simulation analysis was conducted to investigate their dynamic response characteristics.The advantages and disadvantages of two types of energy storage power stations are discussed,and a configuration strategy for hybrid ESS is proposed.This paper presents research on and a simulation analysis of grid-forming and grid-following hybrid energy storage systems considering two types of energy storage according to different capacity scenarios.Finally,a comparative analysis between the systems is presented.A simulation model was established using PSD-BPA(Power System Department-Bonneville Power Administration)to analyze the impact of the capacity ratio of grid-following and grid-forming ESS on their dynamic response characteristics in a hybrid ESS.In addition,a development direction for future ESSs is indicated.展开更多
Background:Crop-tree thinning (CTT) is a forest management practice aiming at enhancing the growth of target trees in plantations by harvesting neighboring trees. Along with the positive effect on tree growth, thinnin...Background:Crop-tree thinning (CTT) is a forest management practice aiming at enhancing the growth of target trees in plantations by harvesting neighboring trees. Along with the positive effect on tree growth, thinning represents a disturbance, which likely affects belowground organisms and may feed back to stand productivity.However, the impact of CTT on the belowground food web is poorly understood. Since nematodes are species-rich and abundant belowground organisms, occupying a variety of trophic positions in soil food webs and being sensitive to disturbances, they serve as ecological indicators of ecosystem disturbance.Results:We studied the effect of CTT on the soil nematode community structure in pine (Pinus massoniana Lamb.),Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) and cypress (Cupressus funebris Endl.) plantations in the Sichuan Basin three years after applying CTT. Crop-tree thinning significantly increased the abundance of soil nematodes in each of the plantations. Moreover, CTT significantly increased the relative abundance of herbivorous nematodes in each of the plantations. Furthermore, CTT increased the proportion of stress tolerators (c-p 1)and enrichment opportunists (c-p 2) and reduced the maturity, structure and enrichment indices of nematodes in Chinese fir and cypress plantations, while only subtle changes were observed in pine plantations. Interestingly,across plantations, the effects of CTT on soil nematode communities were mainly due to changes in microbial biomass nitrogen and understory vegetation diversity.Conclusions:Forest management practices resulting in more open canopies uniformly affect soil food webs by changing the quantity and quality of resources associated with increased understory cover and diversity as well as microbial food. These insights increase our understanding of the impacts of forest management on the structure and functioning of belowground communities, which may contribute to management and conservation policies for more sustainable forestry.展开更多
To solve the problem that the magnetic resonance(MR)image has weak boundaries,large amount of information,and low signal-to-noise ratio,we propose an image segmentation method based on the multi-resolution Markov rand...To solve the problem that the magnetic resonance(MR)image has weak boundaries,large amount of information,and low signal-to-noise ratio,we propose an image segmentation method based on the multi-resolution Markov random field(MRMRF)model.The algorithm uses undecimated dual-tree complex wavelet transformation to transform the image into multiple scales.The transformed low-frequency scale histogram is used to improve the initial clustering center of the K-means algorithm,and then other cluster centers are selected according to the maximum distance rule to obtain the coarse-scale segmentation.The results are then segmented by the improved MRMRF model.In order to solve the problem of fuzzy edge segmentation caused by the gray level inhomogeneity of MR image segmentation under the MRMRF model,it is proposed to introduce variable weight parameters in the segmentation process of each scale.Furthermore,the final segmentation results are optimized.We name this algorithm the variable-weight multi-resolution Markov random field(VWMRMRF).The simulation and clinical MR image segmentation verification show that the VWMRMRF algorithm has high segmentation accuracy and robustness,and can accurately and stably achieve low signal-to-noise ratio,weak boundary MR image segmentation.展开更多
The synthesis of polyoxymethylene dimethyl ethers as an ideal diesel fuel additive is the current hot topic of modern petrochemical industry for their expedient properties in mitigating air pollutants emission during ...The synthesis of polyoxymethylene dimethyl ethers as an ideal diesel fuel additive is the current hot topic of modern petrochemical industry for their expedient properties in mitigating air pollutants emission during combustion.In this work,a series of spherical sulfated zirconia catalysts were prepared by a one-pot hydrothermal method assisted with surfactant cetyltrimethylammonium bromide(CTAB).The prepared sulfated zirconia catalysts were used to catalyze PODEn synthesis from methanol and formaldehyde solution.Various characterization(XRD,BET,SEM,TGA,NH_(3)-TPD,FTIR,and Py-IR)were employed to elaborate the structure–activity relationship of the studied catalytic system.The results demonstrated that S/Zr molar ratio in precursor solution played an effective role on catalyst morphology and acidic properties,where the weak Brønsted acid sites and strong Lewis acid sites were favorable to the conversion of methanol and formation of long-chain PODEn,respectively.The reaction parameters such as catalyst amount,molar ratio of FA/MeOH,reaction time,temperature and pressure were optimized.The speculated reaction pathway for PODEn synthesis was proposed based on the synergy of Brønsted and Lewis acid sites,which suggested that Brønsted and Lewis acid sites might be advantageous to the activation of polyoxymethylene hemiformals[CH_(3)(OCH_(2))_(n)OH]and methylene glycol(HOCH_(2)OH),respectively.展开更多
Layered black phosphorus(BP)has recently emerged as a promising semiconductor because of its tunable band gap,high carrier mobility and strongly in-plane anisotropic properties.One-dimensional(1 D)BP materials are att...Layered black phosphorus(BP)has recently emerged as a promising semiconductor because of its tunable band gap,high carrier mobility and strongly in-plane anisotropic properties.One-dimensional(1 D)BP materials are attractive for applications in electronic and thermal devices,owing to their tailored charge and phonon transports along certain orientations.However,the fabrication of 1 D BP materials still remains elusive thus far.We herein report the successful synthesis and characterization of nanotube-like BP for the first time by a selective composite with hexagonal boron nitride(h-BN)nanotubes under high pressure and high temperature conditions.The produced 1 D BP/h-BN composites possess flexible diameter,length and thickness by adjusting the experimental synthesis parameters.Interestingly,it is important to notice that the stability of our BP sample has been significantly improved under the formation of heterostructures,which can actively promote their commercial applications.Our experimental work,together with first-principles calculations,presents a new scalable strategy of designing 1 D tube-like BP/h-BN heterostructures that are promising candidates for flexible and high efficiency electronic platform.展开更多
Since determining the weight of pigs during large-scale breeding and production is challenging,using non-contact estimation methods is vital.This study proposed a novel pig weight prediction method based on a mod-ifie...Since determining the weight of pigs during large-scale breeding and production is challenging,using non-contact estimation methods is vital.This study proposed a novel pig weight prediction method based on a mod-ified mask region-convolutional neural network(mask R-CNN).The modified approach used ResNeSt as the backbone feature extraction network to enhance the image feature extraction ability.The feature pyramid net-work(FPN)was added to the backbone feature extraction network for multi-scale feature fusion.The channel at-tention mechanism(CAM)and spatial attention mechanism(SAM)were introduced in the region proposal network(RPN)for the adaptive integration of local features and their global dependencies to capture global in-formation,ultimately improving image segmentation accuracy.The modified network obtained a precision rate(P),recall rate(R),and mean average precision(MAP)of 90.33%,89.85%,and 95.21%,respectively,effectively segmenting the pig regions in the images.Five image features,namely the back area,body length,body width,average depth,and eccentricity,were investigated.The pig depth images were used to build five regression algo-rithms(ordinary least squares(OLS),AdaBoost,CatBoost,XGBoost,and random forest(RF))for weight value pre-diction.AdaBoost achieved the best prediction result with a coefficient of determination(R^(2))of 0.987,a mean absolute error(MAE)of 2.96 kg,a mean square error(MSE)of 12.87 kg^(2),and a mean absolute percentage error(MAPE)of 8.45%.The results demonstrated that the machine learning models effectively predicted the weight values of the pigs,providing technical support for intelligent pig farm management.展开更多
Kitaev quantum spin liquids have attracted significant attention in condensed matter physics over the past decade.To understand their emergent quantum phenomena,high-quality single crystals of substantial size are ess...Kitaev quantum spin liquids have attracted significant attention in condensed matter physics over the past decade.To understand their emergent quantum phenomena,high-quality single crystals of substantial size are essential.Here,we report the synthesis of single crystals of the Kitaev quantum spin liquid candidate RuBr_(3),achieving millimeter-sized crystals through a self-flux method under high pressure and high temperature conditions.The crystals exhibit well-defined cleavage planes with a lustrous appearance.Transport characterizations exhibit a narrow band-gap semiconducting behavior with 0.13 eV and 0.11 eV band-gap in ab plane and along𝑐axis,respectively.Magnetic measurement shows a transition to antiferromagnetic(AFM)state at approximately 29K both in ab plane and along the c axis.Notably,the N′eel temperature increases to 34K with an applied magnetic field of up to 7T in the ab plane,but without any change along𝑐axis.The large size and high quality of RuBr3 single crystals provide a valuable platform for investigating various interactions,particularly the Kitaev interaction,and for elucidating the intrinsic physical properties of Kitaev quantum spin liquids.展开更多
In the current study, the effects of a combined application between micro-vortex generator and boundary layer suction on the flow characteristics of a high-load compressor cascade are investigated. The micro-vortex ge...In the current study, the effects of a combined application between micro-vortex generator and boundary layer suction on the flow characteristics of a high-load compressor cascade are investigated. The micro-vortex generator with a special configuration and the longitudinal suction slot are adopted. The calculated results show that a reverse flow region, which is considered the main reason for occurring stall at 7.9° incidence, grows and collapses rapidly near the leading edge and leads to two critical points occurring on the end-wall with the increasing incidence in the baseline. As the micro-vortex generator is introduced in the baseline cascade, the corner separation is switched to a trailing edge separation by the thrust from the induced vortex. Meanwhile, the occurrence of failure is delayed due to the mixed low energy fluid and main flow. The synergistic effects between the micro-vortex generator and the boundary layer suction on the performance of the cascade are superior to the baseline at all the incidence conditions before the occurrence of failure, and the sudden deterioration of the cascade occurs at 10.3° incidence. The optimal results show that the farther upstream suction position, the lower total pressure loss of the cascade with vortex generator at the near stall condition. Moreover, the induced vortex with a leg can migrate the accumulated low energy fluid backward to delay the occurrence of stall.展开更多
Efficient hydrogen production via photocatalysis with high utilization efficiency of Pt cocatalyst is of great importance for sustainable development. In this work, we report an in situ auto-reduction strategy to enca...Efficient hydrogen production via photocatalysis with high utilization efficiency of Pt cocatalyst is of great importance for sustainable development. In this work, we report an in situ auto-reduction strategy to encapsulate highly dispersed Pt clusters inside the cages of MIL-125-NH_(2). The amino groups in MIL-125-NH_(2) first react with formaldehyde to form reducing groups (i.e.,–NH-CH_(2)OH), which can in situ auto-reduce the confined Pt^(2+) ions to ultrasmall Pt clusters within the cavities. With optimized Pt content, photocatalytic H_(2) production over the obtained Pt(1.5)/MIL-125-NH-CH_(2)OH catalyst with 1.43 wt.% Pt loading achieved as high as 4,496.4 µmol·g^(-1)·h^(-1) under visible light (λ > 420 nm) due to the facilitated transfer and separation of the photo-induced charger carriers arising from the synergetic effects between highly dispersed Pt clusters and MIL-125-NH-CH_(2)OH framework. This in situ auto-reduction strategy may be extended to encapsulate various kinds of metal or alloy clusters/nanoparticles within amino-functioned metal-organic frameworks (MOFs) with superior properties and excellent performance.展开更多
Photocatalytic oxidation of organic molecules into highly value-added products is an innovative and challenging research which has gradually attracted remarkable attention of scientists.In this work,it is demonstrated...Photocatalytic oxidation of organic molecules into highly value-added products is an innovative and challenging research which has gradually attracted remarkable attention of scientists.In this work,it is demonstrated that the COF-TpPa with keto-enol tautomerism equilibrium structure shows excellent performance(yield>99%after 8 h)in the selective photocatalytic oxidative coupling of amines to imines under visible light irradiation.It is revealed that three kinds of reactive oxygen species(superoxide radical,hydroxyl radical and singlet oxygen)participate in this photocatalytic oxidation reaction.In addition,hydrogen protons cleaved from the benzyl are proven to be reduced to hydrogen in the conduction band of COF-TpPa in anaerobic atmosphere,accompanied with the formation of imines.The direct hydrogen evolution from amine provides an effective way to extract clean energy from organic molecule as well as the production of value-added chemicals.As a contrast,COF-LZU1 with similar structure and chemical composition to COF-TpPa but without keto-enol tautomerism exhibits worse optical properties and photocatalytic performance.It is also demonstrated that keto-enol tautomerism favors the adsorption of benzylamine based on the characterization results and theoretical calculations.展开更多
Retired power battery construction energy storage systems(ESSs)for echelon utilization can not only extend the remaining capacity value of the battery,and decrease environmental pollution,but also reduce the initial c...Retired power battery construction energy storage systems(ESSs)for echelon utilization can not only extend the remaining capacity value of the battery,and decrease environmental pollution,but also reduce the initial cost of energy storage systems.In this paper,an ESS constructed of retired power batteries for echelon utilization in microgrids(MGs)is considered.Firstly,considering the influence of different discharge depths on the battery life cycle,the correlation equation between the state of charge(SOC)and the state of health(SOH)is established.Secondly,the accelerated life test method,based on the inverse power law coefficient equation,is proposed,and it is used to evaluate the reliability of the ESS.Finally,according to the SOC characteristics,the dynamic security margin of the ESS is established.The life cycle cost,supply-demand balance and ESS balanced control are comprehensively considered,and the location and capacity of energy storage in MGs are determined.It is simulated using the IEEE-RTS 24 node system;the results show that the investment cost of the ESS is reduced and the operational life is prolonged.展开更多
This paper proposes a new cost-efficient,adaptive,and self-healing algorithm in real time that detects faults in a short period with high accuracy,even in the situations when it is difficult to detect.Rather than usin...This paper proposes a new cost-efficient,adaptive,and self-healing algorithm in real time that detects faults in a short period with high accuracy,even in the situations when it is difficult to detect.Rather than using traditional machine learning(ML)algorithms or hybrid signal processing techniques,a new framework based on an optimization enabled weighted ensemble method is developed that combines essential ML algorithms.In the proposed method,the system will select and compound appropriate ML algorithms based on Particle Swarm Optimization(PSO)weights.For this purpose,power system failures are simulated by using the PSCA D-Python co-simulation.One of the salient features of this study is that the proposed solution works on real-time raw data without using any pre-computational techniques or pre-stored information.Therefore,the proposed technique will be able to work on different systems,topologies,or data collections.The proposed fault detection technique is validated by using PSCAD-Python co-simulation on a modified and standard IEEE-14 and standard IEEE-39 bus considering network faults which are difficult to detect.展开更多
Microcystin-leucine arginine(MC-LR),a representative cyanobacterial toxin,poses an increasing and serious threat to aquatic ecosystems.Despite investigating its toxic effects in various organisms and cells,the toxicit...Microcystin-leucine arginine(MC-LR),a representative cyanobacterial toxin,poses an increasing and serious threat to aquatic ecosystems.Despite investigating its toxic effects in various organisms and cells,the toxicity to tissue regeneration and stem cells in vivo still needs to be explored.Planarians are ideal regeneration and toxicology research models and have profound implications in ecotoxicology evaluation.This study conducted a systemic toxicity evaluation of MC-LR,including morphological changes,growth,regeneration,and the underlying cellular and molecular changes after MC-LR exposure,which were investigated in planarians.The results showed that exposure to MC-LR led to time-and dose-dependent lethal morphological changes,tissue damage,degrowth,and delayed regeneration in planarians.Furthermore,MC-LR exposure disturbed the activities of antioxidants,including total superoxide dismutase,catalase,glutathione peroxidase,glutathione S-transferase,and total antioxidant capacity,leading to oxidative stress and DNA damage,and then reduced the number of dividing neoblasts and promoted apoptosis.The results demonstrated that oxidative stress and DNA damage induced by MC-LR exposure caused apoptosis.Excessive apoptosis and suppressed neoblast activity led to severe homeostasis imbalance.This study explores the underlying mechanism of MC-LR toxicity in planarians and provides a basis for the toxicity assessment of MC-LR to aquatic organisms and ecological risk evaluation.展开更多
Battery energy storage system(BESS)is one of the effective technologies to deal with power fluctuation and intermittence resulting from grid integration of large renewable generations.In this paper,the system configur...Battery energy storage system(BESS)is one of the effective technologies to deal with power fluctuation and intermittence resulting from grid integration of large renewable generations.In this paper,the system configuration of a China’s national renewable generation demonstration project combining a large-scale BESS with wind farm and photovoltaic(PV)power station,all coupled to a power transmission system,is introduced,and the key technologies including optimal control and management as well as operational status of this BESS are presented.Additionally,the technical benefits of such a large-scale BESS in dealing with power fluctuation and intermittence issues resulting from grid connection of large-scale renewable generation,and for improvement of operation characteristics of transmission grid,are discussed with relevant case studies.展开更多
Energy storage is one of the key means for improving the flexibility,economy and security of power system.It is also important in promoting new energy consumption and the energy Internet.Therefore,energy storage is ex...Energy storage is one of the key means for improving the flexibility,economy and security of power system.It is also important in promoting new energy consumption and the energy Internet.Therefore,energy storage is expected to support distributed power and the micro-grid,promote open sharing and flexible trading of energy production and consumption,and realize multi-functional coordination.In recent years,with the rapid development of the battery energy storage industry,its technology has shown the characteristics and trends for large-scale integration and distributed applications with multi-objective collaboration.As a grid-level application,energy management systems(EMS)of a battery energy storage system(BESS)were deployed in real time at utility control centers as an important component of power grid management.Based on the analysis of the development status of a BESS,this paper introduced application scenarios,such as reduction of power output fluctuations,agreement to the output plan at the renewable energy generation side,power grid frequency adjustment,power flow optimization at the power transmission side,and a distributed and niohile energy storage system at the power distribution side.The studies and application status of a BESS in recent years were reviewed.The energy management,operation control methods,and application scenes of large-scale BESSs were also examined in the study.展开更多
Distribution networks are commonly used to demonstrate low-voltage problems.A new method to improve voltage quality is using battery energy storage stations(BESSs),which has a four-quadrant regulating capacity.In this...Distribution networks are commonly used to demonstrate low-voltage problems.A new method to improve voltage quality is using battery energy storage stations(BESSs),which has a four-quadrant regulating capacity.In this paper,an optimal dispatching model of a distributed BESS considering peak load shifting is proposed to improve the voltage distribution in a distribution network.The objective function is to minimize the power exchange cost between the distribution network and the transmission network and the penalty cost of the voltage deviation.In the process,various constraints are considered,including the node power balance,single/two-way power flow,peak load shifting,line capacity,voltage deviation,photovoltaic station operation,main transformer capacity,and power factor of the distribution network.The big M method is used to linearize the nonlinear variables in the objective function and constraints,and the model is transformed into a mixed-integer linear programming problem,which significantly improves the model accuracy.Simulations are performed using the modified IEEE 33-node system.A typical time period is selected to analyze the node voltage variation,and the results show that the maximum voltage deviation can be reduced from 14.06%to 4.54%.The maximum peak-valley difference of the system can be reduced from 8.83 to 4.23 MW,and the voltage qualification rate can be significantly improved.Moreover,the validity of the proposed model is verified through simulations.展开更多
Due to the anonymous and free-for-all characteristics of online forums,it is very hard for human beings to differentiate deceptive reviews from truthful reviews.This paper proposes a deep learning approach for text re...Due to the anonymous and free-for-all characteristics of online forums,it is very hard for human beings to differentiate deceptive reviews from truthful reviews.This paper proposes a deep learning approach for text representation called DCWord (Deep Context representation by Word vectors) to deceptive review identification.The basic idea is that since deceptive reviews and truthful reviews are composed by writers without and with real experience on using the online purchased goods or services,there should be different contextual information of words between them.Unlike state-of-the-art techniques in seeking best linguistic features for representation,we use word vectors to characterize contextual information of words in deceptive and truthful reviews automatically.The average-pooling strategy (called DCWord-A) and maxpooling strategy (called DCWord-M) are used to produce review vectors from word vectors.Experimental results on the Spam dataset and the Deception dataset demonstrate that the DCWord-M representation with LR (Logistic Regression) produces the best performances and outperforms state-of-the-art techniques on deceptive review identification.Moreover,the DCWord-M strategy outperforms the DCWord-A strategy in review representation for deceptive review identification.The outcome of this study provides potential implications for online review management and business intelligence of deceptive review identification.展开更多
Anapole metamaterials have attracted growing attention in recent years due to their unique nonradiating and nontrivial properties. Although anapole modes have been demonstrated in metamaterials with threedimensional s...Anapole metamaterials have attracted growing attention in recent years due to their unique nonradiating and nontrivial properties. Although anapole modes have been demonstrated in metamaterials with threedimensional structures, the design and realization of planar anapole metamaterials in a wide frequency range is still a big challenge. Here we propose and experimentally demonstrate a planar anapole metamaterial consisting of dumbbell-shaped apertures on a stainless-steel sheet at terahertz frequencies. The planar metamaterial can generate a resonant transparency in the terahertz spectrum due to the excitation of the anapole mode.Particularly, the frequency of anapole-induced resonant transparency can be tuned easily in the range of 0.15–0.93 THz by simply varying one geometric parameter of the dumbbell apertures. We anticipate that the resonant transparency in planar anapole metamaterials can be potentially used in filters, sensors, or other photonic devices.展开更多
文摘Neuromyelitis optica is an inflammatory demyelinating disease of the central nervous system that differs from multiple sclerosis.Over the past 20 years,the search for biomarke rs for neuromyelitis optica has been ongoing.Here,we used a bibliometric approach to analyze the main research focus in the field of biomarkers for neuromyelitis optica.Research in this area is consistently increasing,with China and the United States leading the way on the number of studies conducted.The Mayo Clinic is a highly reputable institution in the United States,and was identified as the most authoritative institution in this field.Furthermore,Professor Wingerchuk from the Mayo Clinic was the most authoritative expe rt in this field.Keyword analysis revealed that the terms "neuro myelitis optica"(261 times), "multiple sclerosis"(220 times), "neuromyelitis optica spectrum disorder"(132 times), "aquaporin4"(99 times),and "optical neuritis"(87 times) were the most frequently used keywords in literature related to this field.Comprehensive analysis of the classical literature showed that the majority of publications provide conclusive research evidence supporting the use of aquaporin-4-IgG and neuromyelitis optica-IgG to effectively diagnose and differentiate neuromyelitis optica from multiple sclerosis.Furthermore,aquaporin-4-IgG has emerged as a highly specific diagnostic biomarker for neuromyelitis optica spectrum disorder.Myelin oligodendrocyte glycoprotein-IgG is a diagnostic biomarke r for myelin oligodendrocyte glycoprotein antibody-associated disease.Recent biomarkers for neuromyelitis optica in clude cerebrospinal fluid immunological biomarkers such as glial fibrillary acidic protein,serum astrocyte damage biomarkers like FAM19A5,serum albumin,and gammaaminobutyric acid.The latest prospective clinical trials are exploring the potential of these biomarkers.Preliminary results indicate that glial fibrillary acidic protein is emerging as a promising candidate biomarker for neuromyelitis optica spectrum disorder.The ultimate goal of future research is to identify non-invasive biomarkers with high sensitivity,specificity,and safety for the accurate diagnosis of neuro myelitis optica.
基金supported by Science and Technology Research Project of Jilin Provincial Department of Education,No.JJKH20220072KJ(to XL)Science and Technology Development Program of Jilin Province,No.20200201495JC(to YL)。
文摘The integrity of retinal ganglion cells is tightly associated with diabetic macular degeneration that leads to damage and death of retinal ganglion cells,affecting vision.The major clinical treatments for diabetic macular edema are anti-vascular endothelial growth factor drugs and laser photocoagulation.However,although the macular thickness can be normalized with each of these two therapies used alone,the vision does not improve in many patients.This might result from the incomplete recovery of retinal ganglion cell injury.Therefore,a prospective,non-randomized,controlled clinical trial was designed to investigate the effect of anti-vascular endothelial growth factor drugs combined with laser photocoagulation on the integrity of retinal ganglion cells in patients with diabetic macular edema and its relationship with vision recovery.In this trial,150 patients with diabetic macular edema will be equally divided into three groups according to therapeutic methods,followed by treatment with anti-vascular endothelial growth factor drugs,laser photocoagulation therapy,and their combination.All patients will be followed up for 12 months.The primary outcome measure is retinal ganglion cell-inner plexiform layer thickness at 12 months after treatment.The secondary outcome measures include retinal ganglion cell-inner plexiform layer thickness before and 1,3,6,and 9 months after treatment,retinal nerve fiber layer thickness,best-corrected visual acuity,macular area thickness,and choroidal thickness before and 1,3,6,9,and 12 months after treatment.Safety measure is the incidence of adverse events at 1,3,6,9,and 12 months after treatment.The study protocol hopes to validate the better efficacy and safety of the combined treatment in patients with diabetic macula compared with the other two monotherapies alone during the 12-month follow-up period.The trial is designed to focus on clarifying the time-effect relationship between imaging measures related to the integrity of retinal ganglion cells and best-corrected visual acuity.The trial protocol was approved by the Medical Ethics Committee of the Affiliated Hospital of Beihua University with approval No.(2023)(26)on April 25,2023,and was registered with the Chinese Clinical Trial Registry(registration number:ChiCTR2300072478,June 14,2023,protocol version:2.0).
基金supported by the National Key Research and Development Program of China(Gigawatt Hour Level Lithiumion Battery Energy Storage System Technology,NO.2021YFB2400100Integrated and Intelligent Management and Demonstration Application of Gigawatt Hour Level energy storage station,NO.2021YFB2400105).
文摘As the proportion of renewable energy infiltrating the power grid increases,suppressing its randomness and volatility,reducing its impact on the safe operation of the power grid,and improving the level of new energy consumption are increasingly important.For these purposes,energy storage stations(ESS)are receiving increasing attention.This article discusses the structure,working principle,and control methods of grid-following and grid-forming energy-storage converters,which are currently commonly used.A simulation analysis was conducted to investigate their dynamic response characteristics.The advantages and disadvantages of two types of energy storage power stations are discussed,and a configuration strategy for hybrid ESS is proposed.This paper presents research on and a simulation analysis of grid-forming and grid-following hybrid energy storage systems considering two types of energy storage according to different capacity scenarios.Finally,a comparative analysis between the systems is presented.A simulation model was established using PSD-BPA(Power System Department-Bonneville Power Administration)to analyze the impact of the capacity ratio of grid-following and grid-forming ESS on their dynamic response characteristics in a hybrid ESS.In addition,a development direction for future ESSs is indicated.
基金supported by the National Key Research and Development Program of China (Grant No. 2017YFD060030205)the German Government loans for Sichuan Forestry Sustainable Management (Grant No. G1403083)the“Tianfu Ten Thousand Talents Plan”of Sichuan Province (Grant No. 1922999002). the financial support from the China Scholarship Council (Project No. 202006910045)
文摘Background:Crop-tree thinning (CTT) is a forest management practice aiming at enhancing the growth of target trees in plantations by harvesting neighboring trees. Along with the positive effect on tree growth, thinning represents a disturbance, which likely affects belowground organisms and may feed back to stand productivity.However, the impact of CTT on the belowground food web is poorly understood. Since nematodes are species-rich and abundant belowground organisms, occupying a variety of trophic positions in soil food webs and being sensitive to disturbances, they serve as ecological indicators of ecosystem disturbance.Results:We studied the effect of CTT on the soil nematode community structure in pine (Pinus massoniana Lamb.),Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) and cypress (Cupressus funebris Endl.) plantations in the Sichuan Basin three years after applying CTT. Crop-tree thinning significantly increased the abundance of soil nematodes in each of the plantations. Moreover, CTT significantly increased the relative abundance of herbivorous nematodes in each of the plantations. Furthermore, CTT increased the proportion of stress tolerators (c-p 1)and enrichment opportunists (c-p 2) and reduced the maturity, structure and enrichment indices of nematodes in Chinese fir and cypress plantations, while only subtle changes were observed in pine plantations. Interestingly,across plantations, the effects of CTT on soil nematode communities were mainly due to changes in microbial biomass nitrogen and understory vegetation diversity.Conclusions:Forest management practices resulting in more open canopies uniformly affect soil food webs by changing the quantity and quality of resources associated with increased understory cover and diversity as well as microbial food. These insights increase our understanding of the impacts of forest management on the structure and functioning of belowground communities, which may contribute to management and conservation policies for more sustainable forestry.
基金the National Natural Science Foundation of China(Grant No.11471004)the Key Research and Development Program of Shaanxi Province,China(Grant No.2018SF-251)。
文摘To solve the problem that the magnetic resonance(MR)image has weak boundaries,large amount of information,and low signal-to-noise ratio,we propose an image segmentation method based on the multi-resolution Markov random field(MRMRF)model.The algorithm uses undecimated dual-tree complex wavelet transformation to transform the image into multiple scales.The transformed low-frequency scale histogram is used to improve the initial clustering center of the K-means algorithm,and then other cluster centers are selected according to the maximum distance rule to obtain the coarse-scale segmentation.The results are then segmented by the improved MRMRF model.In order to solve the problem of fuzzy edge segmentation caused by the gray level inhomogeneity of MR image segmentation under the MRMRF model,it is proposed to introduce variable weight parameters in the segmentation process of each scale.Furthermore,the final segmentation results are optimized.We name this algorithm the variable-weight multi-resolution Markov random field(VWMRMRF).The simulation and clinical MR image segmentation verification show that the VWMRMRF algorithm has high segmentation accuracy and robustness,and can accurately and stably achieve low signal-to-noise ratio,weak boundary MR image segmentation.
基金This work was financially supported by National Key Research and Development Program of China(No.2018YFB0604804).
文摘The synthesis of polyoxymethylene dimethyl ethers as an ideal diesel fuel additive is the current hot topic of modern petrochemical industry for their expedient properties in mitigating air pollutants emission during combustion.In this work,a series of spherical sulfated zirconia catalysts were prepared by a one-pot hydrothermal method assisted with surfactant cetyltrimethylammonium bromide(CTAB).The prepared sulfated zirconia catalysts were used to catalyze PODEn synthesis from methanol and formaldehyde solution.Various characterization(XRD,BET,SEM,TGA,NH_(3)-TPD,FTIR,and Py-IR)were employed to elaborate the structure–activity relationship of the studied catalytic system.The results demonstrated that S/Zr molar ratio in precursor solution played an effective role on catalyst morphology and acidic properties,where the weak Brønsted acid sites and strong Lewis acid sites were favorable to the conversion of methanol and formation of long-chain PODEn,respectively.The reaction parameters such as catalyst amount,molar ratio of FA/MeOH,reaction time,temperature and pressure were optimized.The speculated reaction pathway for PODEn synthesis was proposed based on the synergy of Brønsted and Lewis acid sites,which suggested that Brønsted and Lewis acid sites might be advantageous to the activation of polyoxymethylene hemiformals[CH_(3)(OCH_(2))_(n)OH]and methylene glycol(HOCH_(2)OH),respectively.
基金Supported by the National Natural Science Foundation of China(Grant Nos.11804184,11974208,and 21905159)the Shandong Provincial Science Foundation(Grant Nos.ZR2019MA054,2019KJJ020,and ZR2019BA010)。
文摘Layered black phosphorus(BP)has recently emerged as a promising semiconductor because of its tunable band gap,high carrier mobility and strongly in-plane anisotropic properties.One-dimensional(1 D)BP materials are attractive for applications in electronic and thermal devices,owing to their tailored charge and phonon transports along certain orientations.However,the fabrication of 1 D BP materials still remains elusive thus far.We herein report the successful synthesis and characterization of nanotube-like BP for the first time by a selective composite with hexagonal boron nitride(h-BN)nanotubes under high pressure and high temperature conditions.The produced 1 D BP/h-BN composites possess flexible diameter,length and thickness by adjusting the experimental synthesis parameters.Interestingly,it is important to notice that the stability of our BP sample has been significantly improved under the formation of heterostructures,which can actively promote their commercial applications.Our experimental work,together with first-principles calculations,presents a new scalable strategy of designing 1 D tube-like BP/h-BN heterostructures that are promising candidates for flexible and high efficiency electronic platform.
基金supported by the Key R&D Program of Zhejiang(2022C02050)Zhejiang Provincial Natural Science Foundation of China(ZCLTGN24C1301)。
文摘Since determining the weight of pigs during large-scale breeding and production is challenging,using non-contact estimation methods is vital.This study proposed a novel pig weight prediction method based on a mod-ified mask region-convolutional neural network(mask R-CNN).The modified approach used ResNeSt as the backbone feature extraction network to enhance the image feature extraction ability.The feature pyramid net-work(FPN)was added to the backbone feature extraction network for multi-scale feature fusion.The channel at-tention mechanism(CAM)and spatial attention mechanism(SAM)were introduced in the region proposal network(RPN)for the adaptive integration of local features and their global dependencies to capture global in-formation,ultimately improving image segmentation accuracy.The modified network obtained a precision rate(P),recall rate(R),and mean average precision(MAP)of 90.33%,89.85%,and 95.21%,respectively,effectively segmenting the pig regions in the images.Five image features,namely the back area,body length,body width,average depth,and eccentricity,were investigated.The pig depth images were used to build five regression algo-rithms(ordinary least squares(OLS),AdaBoost,CatBoost,XGBoost,and random forest(RF))for weight value pre-diction.AdaBoost achieved the best prediction result with a coefficient of determination(R^(2))of 0.987,a mean absolute error(MAE)of 2.96 kg,a mean square error(MSE)of 12.87 kg^(2),and a mean absolute percentage error(MAPE)of 8.45%.The results demonstrated that the machine learning models effectively predicted the weight values of the pigs,providing technical support for intelligent pig farm management.
基金supported by the National Key Research and Development Program of China(Grant Nos.2023YFA1406000 and 2022YFA1403800)the National Natural Science Foundation of China(Grant Nos.12474002,22171283,22203031,12434005,12204515,and 12074175)support of the Young Elite Scientists Sponsorship Program by CAST(Grant No.2022QNRC001)。
文摘Kitaev quantum spin liquids have attracted significant attention in condensed matter physics over the past decade.To understand their emergent quantum phenomena,high-quality single crystals of substantial size are essential.Here,we report the synthesis of single crystals of the Kitaev quantum spin liquid candidate RuBr_(3),achieving millimeter-sized crystals through a self-flux method under high pressure and high temperature conditions.The crystals exhibit well-defined cleavage planes with a lustrous appearance.Transport characterizations exhibit a narrow band-gap semiconducting behavior with 0.13 eV and 0.11 eV band-gap in ab plane and along𝑐axis,respectively.Magnetic measurement shows a transition to antiferromagnetic(AFM)state at approximately 29K both in ab plane and along the c axis.Notably,the N′eel temperature increases to 34K with an applied magnetic field of up to 7T in the ab plane,but without any change along𝑐axis.The large size and high quality of RuBr3 single crystals provide a valuable platform for investigating various interactions,particularly the Kitaev interaction,and for elucidating the intrinsic physical properties of Kitaev quantum spin liquids.
基金co-supported by the National Natural Science Foundation of China(Grants Nos.51576162 and 51536006)
文摘In the current study, the effects of a combined application between micro-vortex generator and boundary layer suction on the flow characteristics of a high-load compressor cascade are investigated. The micro-vortex generator with a special configuration and the longitudinal suction slot are adopted. The calculated results show that a reverse flow region, which is considered the main reason for occurring stall at 7.9° incidence, grows and collapses rapidly near the leading edge and leads to two critical points occurring on the end-wall with the increasing incidence in the baseline. As the micro-vortex generator is introduced in the baseline cascade, the corner separation is switched to a trailing edge separation by the thrust from the induced vortex. Meanwhile, the occurrence of failure is delayed due to the mixed low energy fluid and main flow. The synergistic effects between the micro-vortex generator and the boundary layer suction on the performance of the cascade are superior to the baseline at all the incidence conditions before the occurrence of failure, and the sudden deterioration of the cascade occurs at 10.3° incidence. The optimal results show that the farther upstream suction position, the lower total pressure loss of the cascade with vortex generator at the near stall condition. Moreover, the induced vortex with a leg can migrate the accumulated low energy fluid backward to delay the occurrence of stall.
基金We acknowledge the financial supports from the National Natural Science Foundation of China(No.51802015)Fundamental Research Funds for the Central Universities(No.FRF-TP-20-005A3)Interdisciplinary Research Project for Young Teachers of USTB(Fundamental Research Funds for the Central Universities)(No.FRF-IDRY-19-020).
文摘Efficient hydrogen production via photocatalysis with high utilization efficiency of Pt cocatalyst is of great importance for sustainable development. In this work, we report an in situ auto-reduction strategy to encapsulate highly dispersed Pt clusters inside the cages of MIL-125-NH_(2). The amino groups in MIL-125-NH_(2) first react with formaldehyde to form reducing groups (i.e.,–NH-CH_(2)OH), which can in situ auto-reduce the confined Pt^(2+) ions to ultrasmall Pt clusters within the cavities. With optimized Pt content, photocatalytic H_(2) production over the obtained Pt(1.5)/MIL-125-NH-CH_(2)OH catalyst with 1.43 wt.% Pt loading achieved as high as 4,496.4 µmol·g^(-1)·h^(-1) under visible light (λ > 420 nm) due to the facilitated transfer and separation of the photo-induced charger carriers arising from the synergetic effects between highly dispersed Pt clusters and MIL-125-NH-CH_(2)OH framework. This in situ auto-reduction strategy may be extended to encapsulate various kinds of metal or alloy clusters/nanoparticles within amino-functioned metal-organic frameworks (MOFs) with superior properties and excellent performance.
基金supported by the National Natural Science Foundation of China (51802015, 51972024)the Fundamental Research Funds for the Central Universities (FRF-TP-20-005A3)the Interdisciplinary Research Project for Young Teachers of USTB (Fundamental Research Funds for the Central Universities) (FRF-IDRY-19-020)。
文摘Photocatalytic oxidation of organic molecules into highly value-added products is an innovative and challenging research which has gradually attracted remarkable attention of scientists.In this work,it is demonstrated that the COF-TpPa with keto-enol tautomerism equilibrium structure shows excellent performance(yield>99%after 8 h)in the selective photocatalytic oxidative coupling of amines to imines under visible light irradiation.It is revealed that three kinds of reactive oxygen species(superoxide radical,hydroxyl radical and singlet oxygen)participate in this photocatalytic oxidation reaction.In addition,hydrogen protons cleaved from the benzyl are proven to be reduced to hydrogen in the conduction band of COF-TpPa in anaerobic atmosphere,accompanied with the formation of imines.The direct hydrogen evolution from amine provides an effective way to extract clean energy from organic molecule as well as the production of value-added chemicals.As a contrast,COF-LZU1 with similar structure and chemical composition to COF-TpPa but without keto-enol tautomerism exhibits worse optical properties and photocatalytic performance.It is also demonstrated that keto-enol tautomerism favors the adsorption of benzylamine based on the characterization results and theoretical calculations.
基金supported by the Science and Technology Project of State Grid Corporation of China(DG71-18-009)。
文摘Retired power battery construction energy storage systems(ESSs)for echelon utilization can not only extend the remaining capacity value of the battery,and decrease environmental pollution,but also reduce the initial cost of energy storage systems.In this paper,an ESS constructed of retired power batteries for echelon utilization in microgrids(MGs)is considered.Firstly,considering the influence of different discharge depths on the battery life cycle,the correlation equation between the state of charge(SOC)and the state of health(SOH)is established.Secondly,the accelerated life test method,based on the inverse power law coefficient equation,is proposed,and it is used to evaluate the reliability of the ESS.Finally,according to the SOC characteristics,the dynamic security margin of the ESS is established.The life cycle cost,supply-demand balance and ESS balanced control are comprehensively considered,and the location and capacity of energy storage in MGs are determined.It is simulated using the IEEE-RTS 24 node system;the results show that the investment cost of the ESS is reduced and the operational life is prolonged.
文摘This paper proposes a new cost-efficient,adaptive,and self-healing algorithm in real time that detects faults in a short period with high accuracy,even in the situations when it is difficult to detect.Rather than using traditional machine learning(ML)algorithms or hybrid signal processing techniques,a new framework based on an optimization enabled weighted ensemble method is developed that combines essential ML algorithms.In the proposed method,the system will select and compound appropriate ML algorithms based on Particle Swarm Optimization(PSO)weights.For this purpose,power system failures are simulated by using the PSCA D-Python co-simulation.One of the salient features of this study is that the proposed solution works on real-time raw data without using any pre-computational techniques or pre-stored information.Therefore,the proposed technique will be able to work on different systems,topologies,or data collections.The proposed fault detection technique is validated by using PSCAD-Python co-simulation on a modified and standard IEEE-14 and standard IEEE-39 bus considering network faults which are difficult to detect.
基金supported by the National Natural Science Foundation of China(Nos.32070427,32270501,32200376,and 31570376)the Major Public Welfare Project of Henan Province(201300311700)the Puyang Field Scientific Observation and Research Station for Yellow River Wetland Ecosystem,Henan Province.
文摘Microcystin-leucine arginine(MC-LR),a representative cyanobacterial toxin,poses an increasing and serious threat to aquatic ecosystems.Despite investigating its toxic effects in various organisms and cells,the toxicity to tissue regeneration and stem cells in vivo still needs to be explored.Planarians are ideal regeneration and toxicology research models and have profound implications in ecotoxicology evaluation.This study conducted a systemic toxicity evaluation of MC-LR,including morphological changes,growth,regeneration,and the underlying cellular and molecular changes after MC-LR exposure,which were investigated in planarians.The results showed that exposure to MC-LR led to time-and dose-dependent lethal morphological changes,tissue damage,degrowth,and delayed regeneration in planarians.Furthermore,MC-LR exposure disturbed the activities of antioxidants,including total superoxide dismutase,catalase,glutathione peroxidase,glutathione S-transferase,and total antioxidant capacity,leading to oxidative stress and DNA damage,and then reduced the number of dividing neoblasts and promoted apoptosis.The results demonstrated that oxidative stress and DNA damage induced by MC-LR exposure caused apoptosis.Excessive apoptosis and suppressed neoblast activity led to severe homeostasis imbalance.This study explores the underlying mechanism of MC-LR toxicity in planarians and provides a basis for the toxicity assessment of MC-LR to aquatic organisms and ecological risk evaluation.
基金supported by National Natural Science Foundation of China(No.51107126 and No.512111046)the Key Projects in National Science and Technology Pillar Program(No.2011BAA07B07)+1 种基金the Beiing Nova Program(No.Z141101001814094)the Science and Technology Foundation of State Grid Corporation of China(No.DG71-14-032)
文摘Battery energy storage system(BESS)is one of the effective technologies to deal with power fluctuation and intermittence resulting from grid integration of large renewable generations.In this paper,the system configuration of a China’s national renewable generation demonstration project combining a large-scale BESS with wind farm and photovoltaic(PV)power station,all coupled to a power transmission system,is introduced,and the key technologies including optimal control and management as well as operational status of this BESS are presented.Additionally,the technical benefits of such a large-scale BESS in dealing with power fluctuation and intermittence issues resulting from grid connection of large-scale renewable generation,and for improvement of operation characteristics of transmission grid,are discussed with relevant case studies.
基金supported by the Science and Technology Project of State Grid Corporation of China(DG71-18-009):Intelligent coordination control and energy optimization management of super-large scale battery energy storage power station based on information physics fusion。
文摘Energy storage is one of the key means for improving the flexibility,economy and security of power system.It is also important in promoting new energy consumption and the energy Internet.Therefore,energy storage is expected to support distributed power and the micro-grid,promote open sharing and flexible trading of energy production and consumption,and realize multi-functional coordination.In recent years,with the rapid development of the battery energy storage industry,its technology has shown the characteristics and trends for large-scale integration and distributed applications with multi-objective collaboration.As a grid-level application,energy management systems(EMS)of a battery energy storage system(BESS)were deployed in real time at utility control centers as an important component of power grid management.Based on the analysis of the development status of a BESS,this paper introduced application scenarios,such as reduction of power output fluctuations,agreement to the output plan at the renewable energy generation side,power grid frequency adjustment,power flow optimization at the power transmission side,and a distributed and niohile energy storage system at the power distribution side.The studies and application status of a BESS in recent years were reviewed.The energy management,operation control methods,and application scenes of large-scale BESSs were also examined in the study.
基金This work was supported by the Science and Technology Project of State Grid Corporation of China“Intelligent Coordination Control and Energy Optimization Management of Super-large Scale Battery Energy Storage Power Station Based on Information Physics Fusion-Simulation Model and Transient Characteristics of Super-large Scale Battery Energy Storage Power Station”(No.DG71-18-009).
文摘Distribution networks are commonly used to demonstrate low-voltage problems.A new method to improve voltage quality is using battery energy storage stations(BESSs),which has a four-quadrant regulating capacity.In this paper,an optimal dispatching model of a distributed BESS considering peak load shifting is proposed to improve the voltage distribution in a distribution network.The objective function is to minimize the power exchange cost between the distribution network and the transmission network and the penalty cost of the voltage deviation.In the process,various constraints are considered,including the node power balance,single/two-way power flow,peak load shifting,line capacity,voltage deviation,photovoltaic station operation,main transformer capacity,and power factor of the distribution network.The big M method is used to linearize the nonlinear variables in the objective function and constraints,and the model is transformed into a mixed-integer linear programming problem,which significantly improves the model accuracy.Simulations are performed using the modified IEEE 33-node system.A typical time period is selected to analyze the node voltage variation,and the results show that the maximum voltage deviation can be reduced from 14.06%to 4.54%.The maximum peak-valley difference of the system can be reduced from 8.83 to 4.23 MW,and the voltage qualification rate can be significantly improved.Moreover,the validity of the proposed model is verified through simulations.
基金supported in part by National Natural Science Foundation of China under Grant Nos.71932002,61379046,91318302 and 61432001the Innovation Fund Project of Xi'an Science and Technology Program(Special Series for Xi'an University under Grant No.2016CXWL21).
文摘Due to the anonymous and free-for-all characteristics of online forums,it is very hard for human beings to differentiate deceptive reviews from truthful reviews.This paper proposes a deep learning approach for text representation called DCWord (Deep Context representation by Word vectors) to deceptive review identification.The basic idea is that since deceptive reviews and truthful reviews are composed by writers without and with real experience on using the online purchased goods or services,there should be different contextual information of words between them.Unlike state-of-the-art techniques in seeking best linguistic features for representation,we use word vectors to characterize contextual information of words in deceptive and truthful reviews automatically.The average-pooling strategy (called DCWord-A) and maxpooling strategy (called DCWord-M) are used to produce review vectors from word vectors.Experimental results on the Spam dataset and the Deception dataset demonstrate that the DCWord-M representation with LR (Logistic Regression) produces the best performances and outperforms state-of-the-art techniques on deceptive review identification.Moreover,the DCWord-M strategy outperforms the DCWord-A strategy in review representation for deceptive review identification.The outcome of this study provides potential implications for online review management and business intelligence of deceptive review identification.
基金National Natural Science Foundation of China(61875179,61875251,12004362)Primary Research and Development Plan of Zhejiang Province(2019C03114)。
文摘Anapole metamaterials have attracted growing attention in recent years due to their unique nonradiating and nontrivial properties. Although anapole modes have been demonstrated in metamaterials with threedimensional structures, the design and realization of planar anapole metamaterials in a wide frequency range is still a big challenge. Here we propose and experimentally demonstrate a planar anapole metamaterial consisting of dumbbell-shaped apertures on a stainless-steel sheet at terahertz frequencies. The planar metamaterial can generate a resonant transparency in the terahertz spectrum due to the excitation of the anapole mode.Particularly, the frequency of anapole-induced resonant transparency can be tuned easily in the range of 0.15–0.93 THz by simply varying one geometric parameter of the dumbbell apertures. We anticipate that the resonant transparency in planar anapole metamaterials can be potentially used in filters, sensors, or other photonic devices.
