Deep oil and gas reservoirs are under high-temperature conditions,but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability...Deep oil and gas reservoirs are under high-temperature conditions,but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability,resulting in distorted resource assessments.The development of in situ temperaturepreserved coring(ITP-Coring)technology for deep reservoir rock is urgent,and thermal insulation materials are key.Therefore,hollow glass microsphere/epoxy resin thermal insulation materials(HGM/EP materials)were proposed as thermal insulation materials.The materials properties under coupled hightemperature and high-pressure(HTHP)conditions were tested.The results indicated that high pressures led to HGM destruction and that the materials water absorption significantly increased;additionally,increasing temperature accelerated the process.High temperatures directly caused the thermal conductivity of the materials to increase;additionally,the thermal conduction and convection of water caused by high pressures led to an exponential increase in the thermal conductivity.High temperatures weakened the matrix,and high pressures destroyed the HGM,which resulted in a decrease in the tensile mechanical properties of the materials.The materials entered the high elastic state at 150℃,and the mechanical properties were weakened more obviously,while the pressure led to a significant effect when the water absorption was above 10%.Meanwhile,the tensile strength/strain were 13.62 MPa/1.3%and 6.09 MPa/0.86%at 100℃ and 100 MPa,respectively,which meet the application requirements of the self-designed coring device.Finally,K46-f40 and K46-f50 HGM/EP materials were proven to be suitable for ITP-Coring under coupled conditions below 100℃ and 100 MPa.To further improve the materials properties,the interface layer and EP matrix should be optimized.The results can provide references for the optimization and engineering application of materials and thus technical support for deep oil and gas resource development.展开更多
Abstract A method of Baotou mixed rare earth concen- trate leaching was investigated. According to the principle of complex leaching, the quadratic orthogonal regression experiment was used to investigate effect of si...Abstract A method of Baotou mixed rare earth concen- trate leaching was investigated. According to the principle of complex leaching, the quadratic orthogonal regression experiment was used to investigate effect of six factors. An optimal condition of low energy and environment friendly was determined as follows： HCl acidity is 4 mol.L-1, AlCl3 concentration is 2 mol.L-l, reaction temperature is 85 ℃, reaction time is 90 rain, liquid to solid ratio is 35 ml.g-1, and stirring speed is 100 r.min-1. According to this condition, the leaching ratio of mixed rare earth con- centrate is 76.5 %. The analyses of X-ray diffraction shows that bastnasite disappears, and the main peaks of filter residue is monazite and cheralite after leaching of HCl- AlCl3 solution. The result indicates that REFCO3 of the mixed rare earth concentrate can be dissolved, but REPO4 remains in the leaching residue. This method provides a way to separate and extract rare earth.展开更多
AIM： To establish a visceral pain model via colorectal distension （CRD） and to evaluate the efficiency of behavioral responses of CRD by measuring the score of abdominal withdrawal reflex （AWR） in rats. METHODS：...AIM： To establish a visceral pain model via colorectal distension （CRD） and to evaluate the efficiency of behavioral responses of CRD by measuring the score of abdominal withdrawal reflex （AWR） in rats. METHODS： Thirty-eight male SD rats weighing 180-240g were used to establish the visceral pain model. The rat was inserted intra-anally with a 7 cm long flexible latex balloon under ether anesthesia, and colorectal distensions by inflating the balloon with air were made 30 min after recovering from the anesthesia. Five AWR scores （AWR0 to AWR4） were used to assess the intensity of noxious visceral stimuli. It was regarded as the threshold of the minimal pressure （kPa）. For abdominal flatting was induced by colorectal distension. RESULTS： A vigorous AWR to distension of the descending colon and rectum was found in 100% of the awake rats tested. The higher the pressure of distension, the higher the score of AWR. The distension pressures of 0, 2.00, 3.33, 5.33 and 8.00 kPa produced different AWR scores （P〈0.05）. The pain threshold of AWR was constant for up to 80 min after the initial windup （first 1-3 distensions）, the mean threshold was 3.69±0.35 kPa. Systemic administration of morphine sulfate elevated the threshold of visceral pain in a dosedependent and naloxone reversible manner. CONCLUSION： Scoring the AWR during colorectal distensions can assess the intensity of noxious visceral stimulus. Flatting of abdomen （AWR 3） to CRD as the visceral pain threshold is clear, constant and reliable. This pain model and its behavioral assessment are good for research on visceral pain and analgesics.展开更多
The quantitative evaluation of multi-process collaborative operation is of great significance for the improvement of production planning and scheduling in steelmaking–continuous casting sections(SCCSs). However, this...The quantitative evaluation of multi-process collaborative operation is of great significance for the improvement of production planning and scheduling in steelmaking–continuous casting sections(SCCSs). However, this evaluation is difficult since it relies on an in-depth understanding of the operating mechanism of SCCSs, and few existing methods can be used to conduct the evaluation, due to the lack of full-scale consideration of the multiple factors related to the production operation. In this study, three quantitative models were developed, and the multiprocess collaborative operation level was evaluated through the laminar-flow operation degree, the process matching degree, and the scheduling strategy availability degree. Based on the evaluation models for the laminar-flow operation and process matching levels, this study investigated the production status of two steelmaking plants, plants A and B, based on actual production data. The average laminar-flow operation(process matching) degrees of SCCSs were obtained as 0.638(0.610) and 1.000(0.759) for plants A and B, respectively, for the period of April to July 2019. Then, a scheduling strategy based on the optimization of the furnace-caster coordinating mode was suggested for plant A. Simulation experiments showed higher availability than the greedy-based and manual strategies. After the proposed scheduling strategy was applied,the average process matching degree of the SCCS of plant A increased by 4.6% for the period of September to November 2019. The multi-process collaborative operation level was improved with fewer adjustments and interruptions in casting.展开更多
Deep petroleum resources are in a high-temperature environment.However,the traditional deep rock coring method has no temperature preserved measures and ignores the effect of temperature on rock porosity and permeabil...Deep petroleum resources are in a high-temperature environment.However,the traditional deep rock coring method has no temperature preserved measures and ignores the effect of temperature on rock porosity and permeability,which will lead to the distortion of the petroleum resources reserves assessment.Therefore,the hollow glass microspheres/epoxy resin(HGM/EP)composites were innovatively proposed as temperature preserved materials for in-situ temperature-preserved coring(ITP-Coring),and the physical,mechanical,and temperature preserved properties were evaluated.The results indicated that:As the HGM content increased,the density and mechanical properties of the composites gradually decreased,while the water absorption was deficient without hydrostatic pressure.For composites with 50 vol%HGM,when the hydrostatic pressure reached 60 MPa,the water absorption was above 30.19%,and the physical and mechanical properties of composites were weakened.When the hydrostatic pressure was lower than 40 MPa,the mechanical properties and thermal conductivity of composites were almost unchanged.Therefore,the composites with 50 vol%HGM can be used for ITPCoring operations in deep environments with the highest hydrostatic pressure of 40 MPa.Finally,to further understand the temperature preserved performance of composites in practical applications,the temperature preserved properties were measured.An unsteady-state heat transfer model was established based on the test results,then the theoretical change of the core temperature during the coring process was obtained.The above tests results can provide a research basis for deep rock in-situ temperature preserved corer and support accurate assessment of deep petroleum reserves.展开更多
Objective To explore the toxicological mechanism of hydroquinone in human bronchial epithelial cells and to investigate whether DNA polymerase beta is involved in protecting cells from damage caused by hydroquinone. M...Objective To explore the toxicological mechanism of hydroquinone in human bronchial epithelial cells and to investigate whether DNA polymerase beta is involved in protecting cells from damage caused by hydroquinone. Methods DNA polymerase beta knock-down cell line was established via RNA interference as an experimental group. Normal human bronchial epithelial cells and cells transfected with the empty vector of pEGFP-C1 were used as controls. Cells were treated with different concentrations of hydroquinone （ranged from 10 μmol/L to 120 μmol/L） for 4 hours. MTT assay and Comet assay [single-cell gel electrophoresis （SCGE）] were performed respectively to detect the toxicity of hydroquinone. Results assay showed that DNA polymerase beta knock-down cells treated with different concentrations of hydroquinone had a lower absorbance value at 490 nm than the control cells in a dose-dependant manner. Comet assay revealed that different concentrations of hydroquinone caused more severe DNA damage in DNA polymerase beta knock-down cell line than in control cells and there was no significant difference in the two control groups. Conclusions Hydroquinone has significant toxicity to human bronchial epithelial cells and causes DNA damage. DNA polymerase beta knock-down cell line appears more sensitive to hydroquinone than the control cells. The results suggest that DNA polymerase beta is involved in protecting cells from damage caused by hydroquinone.展开更多
Deep petroleum resources are stored under high temperature and pressure conditions,with the temperature having a significant influence on the properties of rocks.Deep in-situ temperature-preserved coring(ITP-coring)de...Deep petroleum resources are stored under high temperature and pressure conditions,with the temperature having a significant influence on the properties of rocks.Deep in-situ temperature-preserved coring(ITP-coring)devices were developed to assess deep petroleum reserves accurately.Herein,hollow glass microspheres(HGMs)/silicone rubber(SR)composites that exhibit excellent thermal insulation properties were prepared as thermal insulation materials for deep ITP-coring devices.The mechanism and process of heat transfer in the composites were explored,as well as their other properties.The results show that the HGMs exhibit good compatibility with the SR matrix.When the volume fraction of the HGMs is increased to 50%,the density of the HGMs/SR composites is reduced from 0.97 to 0.56 g/cm^(3).The HGMs filler introduces large voids into the composites,reducing their thermal conductivity to 0.11 W/m·K.The addition of HGMs into the composites further enhances the thermal stability of the SR,wherein the higher the HGMs filler content,the better the thermal stability of the composites.HGMs significantly enhance the mechanical strength of the SR.HGMs increase the compressive strength of the composites by 828%and the tensile strength by 164%.Overall,HGMs improve the thermal insulation,pressure resistance,and thermal stability of HGMs/SR composites.展开更多
AIM:To investigate the relationship between c.343A>G and c.2216A>C polymorphism sites in the CDH17 gene and colorectal carcinoma.METHODS:Ninety-three non-consanguineous colorectal carcinoma patients admitted to ...AIM:To investigate the relationship between c.343A>G and c.2216A>C polymorphism sites in the CDH17 gene and colorectal carcinoma.METHODS:Ninety-three non-consanguineous colorectal carcinoma patients admitted to the Department of Oncology at the First Affiliated Hospital of Zhengzhou University were included in this study.Ninety-three peripheral venous blood samples,of approximately one milliliter from each patient,were collected betweenDecember 2009 and August 2010.The genomic DNA of these peripheral venous blood samples were extracted and purified using a Fermentas Genomic DNA Purification Kit(Fermentas,CA) according to the manufacturer' s protocol.The single nucleotide polymorphisms(SNPs) of the liver-intestine cadherin(CDH17) gene c.343A>G and c.2216A>C were determined by the polymerase chain reaction-single strand conformation polymorphism method(PCR-SSCP) in 93 peripheral venous blood samples from patients suffering with colorectal carcinoma.Typical samples that showed different migration bands in SSCP were confirmed by sequencing.Directed DNA sequencing was used to check the correctness of the genotype results from the PCR-SSCP method.RESULTS:There was a significant association between the c.2216 A>C SNPs of the CDH17 gene and the tumor-node-metastasis(TNM) grade,as well as with lymph node status,in 93 peripheral venous blood samples from colorectal carcinoma patients.The genotype frequencies of A/C,A/A,and C/C were 12.90%,33.33% and 53.76%,respectively.There was a significant correlation between lymph node metastasis,TNM grade,and the genotype distribution(P < 0.05).The C/C genotype raised the risk of lymph node metastasis and the TNM grade.There was a significant difference in the TNM grade and lymph node metastasis between the A/A and C/C genotypes(P = 0.003 and P = 0.013,respectively).Patients with colorectal carcinoma carrying the C allele tended to have a higher risk of lymph node metastasis and have a higher TNM grade.The difference between the TNM grades,as well as the lymph node metastasis of the two alleles,was statistically significant(P < 0.01).CONCLUSION:The SNPs of the CDH17 gene c.2216 A>C might be clinically important in the prognosis of colorectal carcinoma.展开更多
Nano-zinc oxides(ZnO)demonstrate remarkable antibacterial properties.To further enhance the corrosion resistance and antibacterial efficiency of magnesium alloy micro-arc oxidation(MAO)coatings,this study investigates...Nano-zinc oxides(ZnO)demonstrate remarkable antibacterial properties.To further enhance the corrosion resistance and antibacterial efficiency of magnesium alloy micro-arc oxidation(MAO)coatings,this study investigates the preparation of ZnO-containing micro-arc oxidation coatings with dual functionality by incorporating nano-ZnO into MAO electrolyte.The influence of varying ZnO concentrations on the microstructure,corrosion resistance,and antibacterial properties of the coating was examined through microstructure analysis,immersion tests,electrochemical experiments,and antibacterial assays.The findings revealed that the addition of nano-ZnO significantly enhanced the corrosion resistance of the MAO-coated alloy.Specifically,when the ZnO concentration in the electrolyte was 5 g/L,the corrosion rate was more than ten times lower compared to the MAO coatings without ZnO.Moreover,the antibacterial efficacy of ZnO+MAO coating,prepared with a ZnO concentration of 5 g/L,surpassed 95%after 24 h of co-culturing with Staphylococcus aureus(S.aureus).The nano-ZnO+MAO-coated alloy exhibited exceptional degradation resistance,corrosion resistance,and antibacterial effectiveness.展开更多
Electrochemical conversion of CO_(2) into valuable chemicals represents a promising strategy to alleviate the environmental issues caused by excessive CO_(2) levels in the atmosphere.In this work,Bi_(2)S_(3) with diff...Electrochemical conversion of CO_(2) into valuable chemicals represents a promising strategy to alleviate the environmental issues caused by excessive CO_(2) levels in the atmosphere.In this work,Bi_(2)S_(3) with different morphologies have been fabricated via facile hydrothermal method to investigate the CO_(2) electrochemical reduction process.展开更多
BACKGROUND Despite advances in treatment,the prognosis for patients with high-risk pediatric solid tumors remains dismal.Tandem autologous stem cell transplantation(ASCT)offers promise for improving outcomes in these ...BACKGROUND Despite advances in treatment,the prognosis for patients with high-risk pediatric solid tumors remains dismal.Tandem autologous stem cell transplantation(ASCT)offers promise for improving outcomes in these patients.This study aimed to examine the efficacy and prognostic factors of tandem ASCT in pediatric patients with high-risk solid tumors.AIM To determine the survival outcomes and prognostic factors in pediatric patients with high-risk solid tumors undergoing tandem ASCT.METHODS A total of 40 pediatric patients with high-risk solid tumors treated from March 2015 to August 2022 were included in this retrospective study.The diagnoses of the patients included neuroblastoma,germ cell tumors,atypical teratoid/rhabdoid tumor,medulloblastoma,and pineoblastoma.After induction chemotherapy,all patients received tandem ASCT and were allocated into two groups(group A and group B)based on high-dose chemotherapy regimens.Prognostic relevance was evaluated by examining patient characteristics,such as sex,age,lactate dehydrogenase levels,primary site,the number of metastatic sites,and bone marrow involvement.RESULTS The median follow-up duration since the first ASCT was 24 months(range:1-91 months),with 5-year overall survival(OS)and event-free survival(EFS)rates of 73%and 70%,respectively,for the entire cohort.The 3-year OS rates were 67%for group A and 87%for group B(P=0.29),with corresponding 3-year EFS rates of 67%and 79%(P=0.57).Among neuroblastoma patients,the 5-year OS and EFS were 69%and 63%(P=0.23).Univariable analysis revealed a notable association of age≥36 months and elevated lactate dehydrogenase level at diagnosis with poorer OS.Despite acute adverse effects,all patients demonstrated good tolerance to the treatment,with no occurrences of transplant-related mortality.CONCLUSION Tandem ASCT demonstrates promising survival outcomes for patients with high-risk solid tumors,particularly neuroblastoma,with manageable toxicity and no transplant-related mortality.展开更多
Carbon coated Si core–shell structures have been proposed to solve the adverse effects of Si-based anode.However,designing ideal core–shell architecture with excellent surface and interface properties is still a sig...Carbon coated Si core–shell structures have been proposed to solve the adverse effects of Si-based anode.However,designing ideal core–shell architecture with excellent surface and interface properties is still a significant challenge.Herein,a novel peanut-like structure of B-doped silicon/carbon nanoparticle(Si@B-C)synthe-sized by sol–gel process and subsequent thermal reduction is reported.The peanut-like Si@B-C electrode demon-strates a superior cyclability of 534 mAh·g^(-1)after 1000 cycles at high current density of 1000 mA·g^(-1).The exceptional electrochemical performance is attributed to the boric acid-induced highly interconnected peanut-like structure and boron heteroatom framework could provide a continuous electron pathway to reduce the irreversible lithium ion loss during rapid cycling.This work provides insight into the development of the heteroatom-doped Si-based anodes with stable cycling performance for LIBs.展开更多
Owing to their high performance and earth abundance,copper sulfides(Cu_(2-x)S)have attracted wide attention as a promising medium-temperature thermoelectric material.Nanostructure and grain-boundary engineering are ex...Owing to their high performance and earth abundance,copper sulfides(Cu_(2-x)S)have attracted wide attention as a promising medium-temperature thermoelectric material.Nanostructure and grain-boundary engineering are explored to tune the electrical transport and phonon scattering of Cu_(2-x)S based on the liquid-like copper ion.Here multiscale architecture-engineered Cu_(2-x)S are fabricated by a room-temperature wet chemical synthesis combining mechanical mixing and spark plasma sintering.The observed electrical conductivity in the multiscale architecture-engineered Cu_(2-x)S is four times as much as that of the Cu_(2-x)S sample at 800 K,which is attributed to the potential energy filtering effect at the new grain boundaries.Moreover,the multiscale architecture in the sintered Cu_(2-x)S increases phonon scattering and results in a reduced lattice thermal conductivity of 0.2 W·m^(-1)·K^(-1) and figure of merit(zT)of 1.0 at 800 K.Such a zT value is one of the record values in copper sulfide produced by chemical synthesis.These results suggest that the introduction of nanostructure and formation of new interface are effective strategies for the enhancement of thermoelectric material properties.展开更多
Duffing equation with fifth nonlinear-restoring force, one external forcing and a phase shift is investigated, The conditions of existences for primary resonance, second-order, third-order subharmonics, morder subharm...Duffing equation with fifth nonlinear-restoring force, one external forcing and a phase shift is investigated, The conditions of existences for primary resonance, second-order, third-order subharmonics, morder subharmonics and chaos are given by using second-averaging method, Melnikov methods and bifurcation theory. Numerical simulations including bifurcation diagrams, bifurcation surfaces, phase portraits, not only show the consistence with the theoretical analysis, but also exhibit the new dynamical behaviors. We show the onset of chaos, chaos suddenly disappearing to period orbit, one-band and double-band chaos, period-doubling bifurcations from period 1, 2, and 3 orbits, period-windows （period-2, 3 and 5） in chaotic regions.展开更多
To optimize ladle scheduling in the empty-ladle operation stage of steel plants,a mathematical scheduling model was established for the empty-ladle operation stage,taking the minimum total waiting time in the empty-la...To optimize ladle scheduling in the empty-ladle operation stage of steel plants,a mathematical scheduling model was established for the empty-ladle operation stage,taking the minimum total waiting time in the empty-ladle operation stage as the optimization goal and setting the equipment assignment uniqueness as the key constraint.An improved genetic algorithm was designed to calculate the mathematical scheduling model.In the operation of the genetic algorithm,the strategy of"ladle temperature drop control"was adopted to solve the problem of equipment conflicts and reduce unreasonable ladle temperature drops to enhance"red-ladle"utilization.Five main production modes operating at 95%capacity in a Chinese steel plant were simulated using the genetic optimization model.The results showed that the genetic optimization model could improve the efficiency of ladle operation and reduce the total waiting time in the empty-ladle operation stage by 868–1147 min.展开更多
This paper is a continuation of ＂Complex Dynamics in Physical Pendulum Equation with Suspension Axis Vibrations＂[1].In this paper,we investigate the existence and the bifurcations of resonant solution for ω0：ω：...This paper is a continuation of ＂Complex Dynamics in Physical Pendulum Equation with Suspension Axis Vibrations＂[1].In this paper,we investigate the existence and the bifurcations of resonant solution for ω0：ω：Ω ≈ 1：1：n,1：2：n,1：3：n,2：1：n and 3：1：n by using second-order averaging method,give a criterion for the existence of resonant solution for ω0：ω：Ω ≈ 1：m：n by using Melnikov＇s method and verify the theoretical analysis by numerical simulations.By numerical simulation,we expose some other interesting dynamical behaviors including the entire invariant torus region,the cascade of invariant torus behaviors,the entire chaos region without periodic windows,chaotic region with complex periodic windows,the entire period-one orbits region;the jumping behaviors including invariant torus behaviors converting to period-one orbits,from chaos to invariant torus behaviors or from invariant torus behaviors to chaos,from period-one to chaos,from invariant torus behaviors to another invariant torus behaviors;the interior crisis;and the different nice invariant torus attractors and chaotic attractors.The numerical results show the difference of dynamical behaviors for the physical pendulum equation with suspension axis vibrations between the cases under the three frequencies resonant condition and under the periodic/quasi-periodic perturbations.It exhibits many invariant torus behaviors under the resonant conditions.We find a lot of chaotic behaviors which are different from those under the periodic/quasi-periodic perturbations.However,we did not find the cascades of period-doubling bifurcation.展开更多
Na superionic conductor(NASICON)-type La_(0.33)Ti_(2)(PO_(4))_(3)(LaTP) is firstly proposed as sodium/potassium storage materials.The density functional theory(DFT) calculations show that LaTP has good electronic char...Na superionic conductor(NASICON)-type La_(0.33)Ti_(2)(PO_(4))_(3)(LaTP) is firstly proposed as sodium/potassium storage materials.The density functional theory(DFT) calculations show that LaTP has good electronic character and low Na^(+)/K^(+)migration barriers.The flexible La_(0.33)Ti_(2)(PO_(4))_(3)/C nanofiber film is synthesized via electrostatic spinning and investigated as free-standing electrode applied to sodium-ion batteries(SIBs) and potassiumion batteries(PIBs) in this work.The low band gap and Na^(+)/K^(+) migration barriers of LaTP,unique morphology,and complete conductive carbon net allow the La_(0.33)Ti_(2)(PO_(4))_(3)/C nanofibers film to deliver high capacity(296.3 mAh·g^(-1) for SIBs and 235.8 mAh·g^(-1) for PIBs),excellent rate performance(142.5 mAh·g^(-1) for SIBs and50.5 mAh·g^(-1) for PIBs at 1.00 A·g^(-1)),and superior cyclability above 1000 cycles.The full-cell tests show that the material has a good application prospect,indicating a promising flexible anode material for SIBs and PIBs.展开更多
Duffing equation with damping and external excitations is investigated. By using Melnikov method and bifurcation theory, the criterions of existence of chaos under periodic perturbations are obtained. By using second-...Duffing equation with damping and external excitations is investigated. By using Melnikov method and bifurcation theory, the criterions of existence of chaos under periodic perturbations are obtained. By using second-order averaging method, the criterions of existence of chaos in averaged system under quasi-periodic perturbations for Ω = nω ＋ εσ, n = 2,4,6 （where σ is not rational to ω） are investigated. However, the criterions of existence of chaos for n = 1, 3, 5, 7 - 20 can not be given. The numerical simulations verify the theoretical analysis, show the occurrence of chaos in the averaged system and original system under quasi- periodic perturbation for n = 1, 2, 3, 5, and expose some new complex dynamical behaviors which can not be given by theoretical analysis. In particular, the dynamical behaviors under quasi-periodic perturbations are different from that under periodic perturbations, and the period-doubling bifurcations to chaos has not been found under quasi-periodic perturbations.展开更多
Precipitation data is vital fundamental data for climate change.However,obtaining precise gauge-measured precipitation in high-altitude mountains is challenging,and the precipitation obtained from various gauge types ...Precipitation data is vital fundamental data for climate change.However,obtaining precise gauge-measured precipitation in high-altitude mountains is challenging,and the precipitation obtained from various gauge types at the same station may vary.To understand the differences in precipitation observations among the three commonly used gauges in China(Chinese Standard Precipitation Gauges(CSPG),Total Rain weighing Sensor(TRwS),and Geonor T-200B(T200B))in high-altitude mountains and to recommend a stable and cost-effective weighing gauge,a precipitation intercomparison experiment was conducted at Hulu-1 station in the Qilian Mountains.The wind-induced error in measurement was corrected with the‘universal’transfer function recommended by the Word Meteorological Organization.The comparison results,adjusted for systematic errors,showed that the rain,snow and mixed precipitation of CSPG and TRwS equipped with the same octagonal vertical double fence shields(CSPGDF and TRwSDF)and single-Alter shields(CSPG_(s)and TRwSs)were close,while the precipitation of Tretyakov-shielded T200B was notably higher than that of CSPG_(s)and TRwSs.The average differences in annual and daily precipitation between CSPGDF and TRwSDF from 2017 to 2021 were 12.9 mm and 0.10 mm,respectively.The daily precipitation difference between CSPG_(s)and TRwSs from April 2019–December 2021 was 0.10 mm,while the differences between T200Bs and CSPG_(s)and TRwSs was 0.28 mm and 0.38 mm,respectively.The wind shield performance of Alter and Tretyakov was not much different at Hulu-1 site with low wind speed,thus the measurement principle of T200Bs was the primary cause of the high observations.Taking the corrected CSPGDF measurement as the standard,the dynamic loss of CSPG_(s)was 17.6%,while that of CSPGUn was 55.6%,indicating that the single-Alter shield could effectively reduce the impact of wind on precipitation measurement.Considering the comparison results and the price difference of the instruments,it was recommended to use a single-Alter shielded TRwS gauge for precipitation observation in high-altitude mountains.展开更多
基金supported by the Sichuan Science and Technology Program (Grant Nos.2023NSFSC0004,2023NSFSC0790)the National Natural Science Foundation of China (Grant Nos.51827901,52304033)the Sichuan University Postdoctoral Fund (Grant No.2024SCU12093)。
文摘Deep oil and gas reservoirs are under high-temperature conditions,but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability,resulting in distorted resource assessments.The development of in situ temperaturepreserved coring(ITP-Coring)technology for deep reservoir rock is urgent,and thermal insulation materials are key.Therefore,hollow glass microsphere/epoxy resin thermal insulation materials(HGM/EP materials)were proposed as thermal insulation materials.The materials properties under coupled hightemperature and high-pressure(HTHP)conditions were tested.The results indicated that high pressures led to HGM destruction and that the materials water absorption significantly increased;additionally,increasing temperature accelerated the process.High temperatures directly caused the thermal conductivity of the materials to increase;additionally,the thermal conduction and convection of water caused by high pressures led to an exponential increase in the thermal conductivity.High temperatures weakened the matrix,and high pressures destroyed the HGM,which resulted in a decrease in the tensile mechanical properties of the materials.The materials entered the high elastic state at 150℃,and the mechanical properties were weakened more obviously,while the pressure led to a significant effect when the water absorption was above 10%.Meanwhile,the tensile strength/strain were 13.62 MPa/1.3%and 6.09 MPa/0.86%at 100℃ and 100 MPa,respectively,which meet the application requirements of the self-designed coring device.Finally,K46-f40 and K46-f50 HGM/EP materials were proven to be suitable for ITP-Coring under coupled conditions below 100℃ and 100 MPa.To further improve the materials properties,the interface layer and EP matrix should be optimized.The results can provide references for the optimization and engineering application of materials and thus technical support for deep oil and gas resource development.
基金financially supported by the National Nature Science Foundation of China (No. 51174115)National Outstanding Youth Science Foundation of China (No. 51025416)Program for Changjiang Scholars and Innovative Research Team in University (No. IRT1065)
文摘Abstract A method of Baotou mixed rare earth concen- trate leaching was investigated. According to the principle of complex leaching, the quadratic orthogonal regression experiment was used to investigate effect of six factors. An optimal condition of low energy and environment friendly was determined as follows： HCl acidity is 4 mol.L-1, AlCl3 concentration is 2 mol.L-l, reaction temperature is 85 ℃, reaction time is 90 rain, liquid to solid ratio is 35 ml.g-1, and stirring speed is 100 r.min-1. According to this condition, the leaching ratio of mixed rare earth con- centrate is 76.5 %. The analyses of X-ray diffraction shows that bastnasite disappears, and the main peaks of filter residue is monazite and cheralite after leaching of HCl- AlCl3 solution. The result indicates that REFCO3 of the mixed rare earth concentrate can be dissolved, but REPO4 remains in the leaching residue. This method provides a way to separate and extract rare earth.
基金Supported by Natural Science Foundation of Jiangsu Province,NO.BK2005033Medical Foundation of Department of Health,Jiangsu Province, No. H200325+1 种基金Natural Science Foundation of Department of Education, Jiangsu Province, No. 04kJB320127Medical Foundation of Department of Health, Zhejiang Province, No. 2004A084
文摘AIM： To establish a visceral pain model via colorectal distension （CRD） and to evaluate the efficiency of behavioral responses of CRD by measuring the score of abdominal withdrawal reflex （AWR） in rats. METHODS： Thirty-eight male SD rats weighing 180-240g were used to establish the visceral pain model. The rat was inserted intra-anally with a 7 cm long flexible latex balloon under ether anesthesia, and colorectal distensions by inflating the balloon with air were made 30 min after recovering from the anesthesia. Five AWR scores （AWR0 to AWR4） were used to assess the intensity of noxious visceral stimuli. It was regarded as the threshold of the minimal pressure （kPa）. For abdominal flatting was induced by colorectal distension. RESULTS： A vigorous AWR to distension of the descending colon and rectum was found in 100% of the awake rats tested. The higher the pressure of distension, the higher the score of AWR. The distension pressures of 0, 2.00, 3.33, 5.33 and 8.00 kPa produced different AWR scores （P〈0.05）. The pain threshold of AWR was constant for up to 80 min after the initial windup （first 1-3 distensions）, the mean threshold was 3.69±0.35 kPa. Systemic administration of morphine sulfate elevated the threshold of visceral pain in a dosedependent and naloxone reversible manner. CONCLUSION： Scoring the AWR during colorectal distensions can assess the intensity of noxious visceral stimulus. Flatting of abdomen （AWR 3） to CRD as the visceral pain threshold is clear, constant and reliable. This pain model and its behavioral assessment are good for research on visceral pain and analgesics.
基金financially supported by the National Natural Science Foundation of China (Nos.50874014 and 51974023)the Fundamental Research Funds for Central Universities (No.FRF-BR-17-029A)。
文摘The quantitative evaluation of multi-process collaborative operation is of great significance for the improvement of production planning and scheduling in steelmaking–continuous casting sections(SCCSs). However, this evaluation is difficult since it relies on an in-depth understanding of the operating mechanism of SCCSs, and few existing methods can be used to conduct the evaluation, due to the lack of full-scale consideration of the multiple factors related to the production operation. In this study, three quantitative models were developed, and the multiprocess collaborative operation level was evaluated through the laminar-flow operation degree, the process matching degree, and the scheduling strategy availability degree. Based on the evaluation models for the laminar-flow operation and process matching levels, this study investigated the production status of two steelmaking plants, plants A and B, based on actual production data. The average laminar-flow operation(process matching) degrees of SCCSs were obtained as 0.638(0.610) and 1.000(0.759) for plants A and B, respectively, for the period of April to July 2019. Then, a scheduling strategy based on the optimization of the furnace-caster coordinating mode was suggested for plant A. Simulation experiments showed higher availability than the greedy-based and manual strategies. After the proposed scheduling strategy was applied,the average process matching degree of the SCCS of plant A increased by 4.6% for the period of September to November 2019. The multi-process collaborative operation level was improved with fewer adjustments and interruptions in casting.
基金National Natural Science Foundation of China(grant number 51827901)funded by the Program for Guangdong Introducing Innovative and Enterpreneurial Teams(No.2019ZT08G315)Shenzhen Basic Research Program(General Program)(No.JCYJ20190808153416970)
文摘Deep petroleum resources are in a high-temperature environment.However,the traditional deep rock coring method has no temperature preserved measures and ignores the effect of temperature on rock porosity and permeability,which will lead to the distortion of the petroleum resources reserves assessment.Therefore,the hollow glass microspheres/epoxy resin(HGM/EP)composites were innovatively proposed as temperature preserved materials for in-situ temperature-preserved coring(ITP-Coring),and the physical,mechanical,and temperature preserved properties were evaluated.The results indicated that:As the HGM content increased,the density and mechanical properties of the composites gradually decreased,while the water absorption was deficient without hydrostatic pressure.For composites with 50 vol%HGM,when the hydrostatic pressure reached 60 MPa,the water absorption was above 30.19%,and the physical and mechanical properties of composites were weakened.When the hydrostatic pressure was lower than 40 MPa,the mechanical properties and thermal conductivity of composites were almost unchanged.Therefore,the composites with 50 vol%HGM can be used for ITPCoring operations in deep environments with the highest hydrostatic pressure of 40 MPa.Finally,to further understand the temperature preserved performance of composites in practical applications,the temperature preserved properties were measured.An unsteady-state heat transfer model was established based on the test results,then the theoretical change of the core temperature during the coring process was obtained.The above tests results can provide a research basis for deep rock in-situ temperature preserved corer and support accurate assessment of deep petroleum reserves.
基金This work was supported by a grant from the Major State Basic Research Development Program of China (No. 2002CB512904, 2002CB512903).
文摘Objective To explore the toxicological mechanism of hydroquinone in human bronchial epithelial cells and to investigate whether DNA polymerase beta is involved in protecting cells from damage caused by hydroquinone. Methods DNA polymerase beta knock-down cell line was established via RNA interference as an experimental group. Normal human bronchial epithelial cells and cells transfected with the empty vector of pEGFP-C1 were used as controls. Cells were treated with different concentrations of hydroquinone （ranged from 10 μmol/L to 120 μmol/L） for 4 hours. MTT assay and Comet assay [single-cell gel electrophoresis （SCGE）] were performed respectively to detect the toxicity of hydroquinone. Results assay showed that DNA polymerase beta knock-down cells treated with different concentrations of hydroquinone had a lower absorbance value at 490 nm than the control cells in a dose-dependant manner. Comet assay revealed that different concentrations of hydroquinone caused more severe DNA damage in DNA polymerase beta knock-down cell line than in control cells and there was no significant difference in the two control groups. Conclusions Hydroquinone has significant toxicity to human bronchial epithelial cells and causes DNA damage. DNA polymerase beta knock-down cell line appears more sensitive to hydroquinone than the control cells. The results suggest that DNA polymerase beta is involved in protecting cells from damage caused by hydroquinone.
基金supported by the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(No.2019ZT08G315)Shenzhen Basic Research Program(General Program)(No.JCYJ20190808153416970)National Natural Science Foundation of China No.51827901 and U2013603。
文摘Deep petroleum resources are stored under high temperature and pressure conditions,with the temperature having a significant influence on the properties of rocks.Deep in-situ temperature-preserved coring(ITP-coring)devices were developed to assess deep petroleum reserves accurately.Herein,hollow glass microspheres(HGMs)/silicone rubber(SR)composites that exhibit excellent thermal insulation properties were prepared as thermal insulation materials for deep ITP-coring devices.The mechanism and process of heat transfer in the composites were explored,as well as their other properties.The results show that the HGMs exhibit good compatibility with the SR matrix.When the volume fraction of the HGMs is increased to 50%,the density of the HGMs/SR composites is reduced from 0.97 to 0.56 g/cm^(3).The HGMs filler introduces large voids into the composites,reducing their thermal conductivity to 0.11 W/m·K.The addition of HGMs into the composites further enhances the thermal stability of the SR,wherein the higher the HGMs filler content,the better the thermal stability of the composites.HGMs significantly enhance the mechanical strength of the SR.HGMs increase the compressive strength of the composites by 828%and the tensile strength by 164%.Overall,HGMs improve the thermal insulation,pressure resistance,and thermal stability of HGMs/SR composites.
基金Supported by 2010A310011 Henan Provincial Department of Education on Natural Science Research Projects
文摘AIM:To investigate the relationship between c.343A>G and c.2216A>C polymorphism sites in the CDH17 gene and colorectal carcinoma.METHODS:Ninety-three non-consanguineous colorectal carcinoma patients admitted to the Department of Oncology at the First Affiliated Hospital of Zhengzhou University were included in this study.Ninety-three peripheral venous blood samples,of approximately one milliliter from each patient,were collected betweenDecember 2009 and August 2010.The genomic DNA of these peripheral venous blood samples were extracted and purified using a Fermentas Genomic DNA Purification Kit(Fermentas,CA) according to the manufacturer' s protocol.The single nucleotide polymorphisms(SNPs) of the liver-intestine cadherin(CDH17) gene c.343A>G and c.2216A>C were determined by the polymerase chain reaction-single strand conformation polymorphism method(PCR-SSCP) in 93 peripheral venous blood samples from patients suffering with colorectal carcinoma.Typical samples that showed different migration bands in SSCP were confirmed by sequencing.Directed DNA sequencing was used to check the correctness of the genotype results from the PCR-SSCP method.RESULTS:There was a significant association between the c.2216 A>C SNPs of the CDH17 gene and the tumor-node-metastasis(TNM) grade,as well as with lymph node status,in 93 peripheral venous blood samples from colorectal carcinoma patients.The genotype frequencies of A/C,A/A,and C/C were 12.90%,33.33% and 53.76%,respectively.There was a significant correlation between lymph node metastasis,TNM grade,and the genotype distribution(P < 0.05).The C/C genotype raised the risk of lymph node metastasis and the TNM grade.There was a significant difference in the TNM grade and lymph node metastasis between the A/A and C/C genotypes(P = 0.003 and P = 0.013,respectively).Patients with colorectal carcinoma carrying the C allele tended to have a higher risk of lymph node metastasis and have a higher TNM grade.The difference between the TNM grades,as well as the lymph node metastasis of the two alleles,was statistically significant(P < 0.01).CONCLUSION:The SNPs of the CDH17 gene c.2216 A>C might be clinically important in the prognosis of colorectal carcinoma.
基金supported by the National Natural Science Foundation of China(No.52001034)the China Postdoctoral Science Foundation(No.2023M731677)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX23_3032).
文摘Nano-zinc oxides(ZnO)demonstrate remarkable antibacterial properties.To further enhance the corrosion resistance and antibacterial efficiency of magnesium alloy micro-arc oxidation(MAO)coatings,this study investigates the preparation of ZnO-containing micro-arc oxidation coatings with dual functionality by incorporating nano-ZnO into MAO electrolyte.The influence of varying ZnO concentrations on the microstructure,corrosion resistance,and antibacterial properties of the coating was examined through microstructure analysis,immersion tests,electrochemical experiments,and antibacterial assays.The findings revealed that the addition of nano-ZnO significantly enhanced the corrosion resistance of the MAO-coated alloy.Specifically,when the ZnO concentration in the electrolyte was 5 g/L,the corrosion rate was more than ten times lower compared to the MAO coatings without ZnO.Moreover,the antibacterial efficacy of ZnO+MAO coating,prepared with a ZnO concentration of 5 g/L,surpassed 95%after 24 h of co-culturing with Staphylococcus aureus(S.aureus).The nano-ZnO+MAO-coated alloy exhibited exceptional degradation resistance,corrosion resistance,and antibacterial effectiveness.
基金financially supported by the the Fundamental Research Funds for the Central Universities (Nos. 2232023D-02 and 2232021A-02)the National Natural Science Foundation of China (Nos.52202361 and 52122312)。
文摘Electrochemical conversion of CO_(2) into valuable chemicals represents a promising strategy to alleviate the environmental issues caused by excessive CO_(2) levels in the atmosphere.In this work,Bi_(2)S_(3) with different morphologies have been fabricated via facile hydrothermal method to investigate the CO_(2) electrochemical reduction process.
基金Guangzhou Municipal Science and Technology Bureau,Municipal School and College Joint Funding Project,No.2024A03J1240.
文摘BACKGROUND Despite advances in treatment,the prognosis for patients with high-risk pediatric solid tumors remains dismal.Tandem autologous stem cell transplantation(ASCT)offers promise for improving outcomes in these patients.This study aimed to examine the efficacy and prognostic factors of tandem ASCT in pediatric patients with high-risk solid tumors.AIM To determine the survival outcomes and prognostic factors in pediatric patients with high-risk solid tumors undergoing tandem ASCT.METHODS A total of 40 pediatric patients with high-risk solid tumors treated from March 2015 to August 2022 were included in this retrospective study.The diagnoses of the patients included neuroblastoma,germ cell tumors,atypical teratoid/rhabdoid tumor,medulloblastoma,and pineoblastoma.After induction chemotherapy,all patients received tandem ASCT and were allocated into two groups(group A and group B)based on high-dose chemotherapy regimens.Prognostic relevance was evaluated by examining patient characteristics,such as sex,age,lactate dehydrogenase levels,primary site,the number of metastatic sites,and bone marrow involvement.RESULTS The median follow-up duration since the first ASCT was 24 months(range:1-91 months),with 5-year overall survival(OS)and event-free survival(EFS)rates of 73%and 70%,respectively,for the entire cohort.The 3-year OS rates were 67%for group A and 87%for group B(P=0.29),with corresponding 3-year EFS rates of 67%and 79%(P=0.57).Among neuroblastoma patients,the 5-year OS and EFS were 69%and 63%(P=0.23).Univariable analysis revealed a notable association of age≥36 months and elevated lactate dehydrogenase level at diagnosis with poorer OS.Despite acute adverse effects,all patients demonstrated good tolerance to the treatment,with no occurrences of transplant-related mortality.CONCLUSION Tandem ASCT demonstrates promising survival outcomes for patients with high-risk solid tumors,particularly neuroblastoma,with manageable toxicity and no transplant-related mortality.
基金the National Natural Science Foundation of China(No.51702046)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning,State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua University。
文摘Carbon coated Si core–shell structures have been proposed to solve the adverse effects of Si-based anode.However,designing ideal core–shell architecture with excellent surface and interface properties is still a significant challenge.Herein,a novel peanut-like structure of B-doped silicon/carbon nanoparticle(Si@B-C)synthe-sized by sol–gel process and subsequent thermal reduction is reported.The peanut-like Si@B-C electrode demon-strates a superior cyclability of 534 mAh·g^(-1)after 1000 cycles at high current density of 1000 mA·g^(-1).The exceptional electrochemical performance is attributed to the boric acid-induced highly interconnected peanut-like structure and boron heteroatom framework could provide a continuous electron pathway to reduce the irreversible lithium ion loss during rapid cycling.This work provides insight into the development of the heteroatom-doped Si-based anodes with stable cycling performance for LIBs.
基金financially supported by the National Natural Science Foundation of China(Nos.51702091 and 51702046)the College Outstanding Young Scientific and Technological Innovation Team of Hubei province(No.T201922)+2 种基金the Special Funding of Preventing the Spread of COVID-19,Hubei University of Education(No.20XGZX20)Fok Ying-Tong Education Foundation of China(No.171041)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning,State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua University。
文摘Owing to their high performance and earth abundance,copper sulfides(Cu_(2-x)S)have attracted wide attention as a promising medium-temperature thermoelectric material.Nanostructure and grain-boundary engineering are explored to tune the electrical transport and phonon scattering of Cu_(2-x)S based on the liquid-like copper ion.Here multiscale architecture-engineered Cu_(2-x)S are fabricated by a room-temperature wet chemical synthesis combining mechanical mixing and spark plasma sintering.The observed electrical conductivity in the multiscale architecture-engineered Cu_(2-x)S is four times as much as that of the Cu_(2-x)S sample at 800 K,which is attributed to the potential energy filtering effect at the new grain boundaries.Moreover,the multiscale architecture in the sintered Cu_(2-x)S increases phonon scattering and results in a reduced lattice thermal conductivity of 0.2 W·m^(-1)·K^(-1) and figure of merit(zT)of 1.0 at 800 K.Such a zT value is one of the record values in copper sulfide produced by chemical synthesis.These results suggest that the introduction of nanostructure and formation of new interface are effective strategies for the enhancement of thermoelectric material properties.
基金Supported by the National Natural Science Foundation of China （No.10371037）, and by Chinese Academy Scicnces （KZCX2-SW-118）
文摘Duffing equation with fifth nonlinear-restoring force, one external forcing and a phase shift is investigated, The conditions of existences for primary resonance, second-order, third-order subharmonics, morder subharmonics and chaos are given by using second-averaging method, Melnikov methods and bifurcation theory. Numerical simulations including bifurcation diagrams, bifurcation surfaces, phase portraits, not only show the consistence with the theoretical analysis, but also exhibit the new dynamical behaviors. We show the onset of chaos, chaos suddenly disappearing to period orbit, one-band and double-band chaos, period-doubling bifurcations from period 1, 2, and 3 orbits, period-windows （period-2, 3 and 5） in chaotic regions.
基金the Fundamental Research Funds for Central Universities(FRF-BR-17-029A).
文摘To optimize ladle scheduling in the empty-ladle operation stage of steel plants,a mathematical scheduling model was established for the empty-ladle operation stage,taking the minimum total waiting time in the empty-ladle operation stage as the optimization goal and setting the equipment assignment uniqueness as the key constraint.An improved genetic algorithm was designed to calculate the mathematical scheduling model.In the operation of the genetic algorithm,the strategy of"ladle temperature drop control"was adopted to solve the problem of equipment conflicts and reduce unreasonable ladle temperature drops to enhance"red-ladle"utilization.Five main production modes operating at 95%capacity in a Chinese steel plant were simulated using the genetic optimization model.The results showed that the genetic optimization model could improve the efficiency of ladle operation and reduce the total waiting time in the empty-ladle operation stage by 868–1147 min.
基金Supported by the National Natural Science Foundation of China (No.10671063 and 10801135)
文摘This paper is a continuation of ＂Complex Dynamics in Physical Pendulum Equation with Suspension Axis Vibrations＂[1].In this paper,we investigate the existence and the bifurcations of resonant solution for ω0：ω：Ω ≈ 1：1：n,1：2：n,1：3：n,2：1：n and 3：1：n by using second-order averaging method,give a criterion for the existence of resonant solution for ω0：ω：Ω ≈ 1：m：n by using Melnikov＇s method and verify the theoretical analysis by numerical simulations.By numerical simulation,we expose some other interesting dynamical behaviors including the entire invariant torus region,the cascade of invariant torus behaviors,the entire chaos region without periodic windows,chaotic region with complex periodic windows,the entire period-one orbits region;the jumping behaviors including invariant torus behaviors converting to period-one orbits,from chaos to invariant torus behaviors or from invariant torus behaviors to chaos,from period-one to chaos,from invariant torus behaviors to another invariant torus behaviors;the interior crisis;and the different nice invariant torus attractors and chaotic attractors.The numerical results show the difference of dynamical behaviors for the physical pendulum equation with suspension axis vibrations between the cases under the three frequencies resonant condition and under the periodic/quasi-periodic perturbations.It exhibits many invariant torus behaviors under the resonant conditions.We find a lot of chaotic behaviors which are different from those under the periodic/quasi-periodic perturbations.However,we did not find the cascades of period-doubling bifurcation.
基金financially supported by the National Natural Science Foundation of China (No. 52072325)the Key Research Foundation of Education Bureau of Hunan Province, China (No. 20A486)+2 种基金Hunan 2011 Collaborative Innovation Center of Chemical Engineering and Technology with Environmental Benignity and Effective Resource Utilization, Program for Innovative Research Cultivation Team in University of Ministry of Education of China (No. 1337304)the 111 Project (No. B12015)the Natural Science Foundation of Shandong Province (No. ZR2020MB045)。
文摘Na superionic conductor(NASICON)-type La_(0.33)Ti_(2)(PO_(4))_(3)(LaTP) is firstly proposed as sodium/potassium storage materials.The density functional theory(DFT) calculations show that LaTP has good electronic character and low Na^(+)/K^(+)migration barriers.The flexible La_(0.33)Ti_(2)(PO_(4))_(3)/C nanofiber film is synthesized via electrostatic spinning and investigated as free-standing electrode applied to sodium-ion batteries(SIBs) and potassiumion batteries(PIBs) in this work.The low band gap and Na^(+)/K^(+) migration barriers of LaTP,unique morphology,and complete conductive carbon net allow the La_(0.33)Ti_(2)(PO_(4))_(3)/C nanofibers film to deliver high capacity(296.3 mAh·g^(-1) for SIBs and 235.8 mAh·g^(-1) for PIBs),excellent rate performance(142.5 mAh·g^(-1) for SIBs and50.5 mAh·g^(-1) for PIBs at 1.00 A·g^(-1)),and superior cyclability above 1000 cycles.The full-cell tests show that the material has a good application prospect,indicating a promising flexible anode material for SIBs and PIBs.
基金Supported by the National Natural Science Foundation of China(No.10801135,11101170)Hunan Provincial Natural Science Foundation of China(No.13JJ4088)talent introduction fund(No.104-0163)
文摘Duffing equation with damping and external excitations is investigated. By using Melnikov method and bifurcation theory, the criterions of existence of chaos under periodic perturbations are obtained. By using second-order averaging method, the criterions of existence of chaos in averaged system under quasi-periodic perturbations for Ω = nω ＋ εσ, n = 2,4,6 （where σ is not rational to ω） are investigated. However, the criterions of existence of chaos for n = 1, 3, 5, 7 - 20 can not be given. The numerical simulations verify the theoretical analysis, show the occurrence of chaos in the averaged system and original system under quasi- periodic perturbation for n = 1, 2, 3, 5, and expose some new complex dynamical behaviors which can not be given by theoretical analysis. In particular, the dynamical behaviors under quasi-periodic perturbations are different from that under periodic perturbations, and the period-doubling bifurcations to chaos has not been found under quasi-periodic perturbations.
基金This study was funded by the National Natural Sciences Foundation of China(42101120,42171145,41971041)the Joint Research Project of Three-River Headwaters National Park,Chinese Academy of Sciences and the People's Government of Qinghai Province(LHZX-2020-11)the Gansu Natural Science Foundation(22JR5RA071).
文摘Precipitation data is vital fundamental data for climate change.However,obtaining precise gauge-measured precipitation in high-altitude mountains is challenging,and the precipitation obtained from various gauge types at the same station may vary.To understand the differences in precipitation observations among the three commonly used gauges in China(Chinese Standard Precipitation Gauges(CSPG),Total Rain weighing Sensor(TRwS),and Geonor T-200B(T200B))in high-altitude mountains and to recommend a stable and cost-effective weighing gauge,a precipitation intercomparison experiment was conducted at Hulu-1 station in the Qilian Mountains.The wind-induced error in measurement was corrected with the‘universal’transfer function recommended by the Word Meteorological Organization.The comparison results,adjusted for systematic errors,showed that the rain,snow and mixed precipitation of CSPG and TRwS equipped with the same octagonal vertical double fence shields(CSPGDF and TRwSDF)and single-Alter shields(CSPG_(s)and TRwSs)were close,while the precipitation of Tretyakov-shielded T200B was notably higher than that of CSPG_(s)and TRwSs.The average differences in annual and daily precipitation between CSPGDF and TRwSDF from 2017 to 2021 were 12.9 mm and 0.10 mm,respectively.The daily precipitation difference between CSPG_(s)and TRwSs from April 2019–December 2021 was 0.10 mm,while the differences between T200Bs and CSPG_(s)and TRwSs was 0.28 mm and 0.38 mm,respectively.The wind shield performance of Alter and Tretyakov was not much different at Hulu-1 site with low wind speed,thus the measurement principle of T200Bs was the primary cause of the high observations.Taking the corrected CSPGDF measurement as the standard,the dynamic loss of CSPG_(s)was 17.6%,while that of CSPGUn was 55.6%,indicating that the single-Alter shield could effectively reduce the impact of wind on precipitation measurement.Considering the comparison results and the price difference of the instruments,it was recommended to use a single-Alter shielded TRwS gauge for precipitation observation in high-altitude mountains.
