Appropriately characterising the mixed space-time relations of the contagion process caused by hybrid space and time factors remains the primary challenge in COVID-19 forecasting.However,in previous deep learning mode...Appropriately characterising the mixed space-time relations of the contagion process caused by hybrid space and time factors remains the primary challenge in COVID-19 forecasting.However,in previous deep learning models for epidemic forecasting,spatial and temporal variations are captured separately.A unified model is developed to cover all spatio-temporal relations.However,this measure is insufficient for modelling the complex spatio-temporal relations of infectious disease transmission.A dynamic adaptive spatio-temporal graph network(DASTGN)is proposed based on attention mechanisms to improve prediction accuracy.In DASTGN,complex spatio-temporal relations are depicted by adaptively fusing the mixed space-time effects and dynamic space-time dependency structure.This dual-scale model considers the time-specific,space-specific,and direct effects of the propagation process at the fine-grained level.Furthermore,the model characterises impacts from various space-time neighbour blocks under time-varying interventions at the coarse-grained level.The performance comparisons on the three COVID-19 datasets reveal that DASTGN achieves state-of-the-art results with a maximum improvement of 17.092%in the root mean-square error and 11.563%in the mean absolute error.Experimental results indicate that the mechanisms of designing DASTGN can effectively detect some spreading characteristics of COVID-19.The spatio-temporal weight matrices learned in each proposed module reveal diffusion patterns in various scenarios.In conclusion,DASTGN has successfully captured the dynamic spatio-temporal variations of COVID-19,and considering multiple dynamic space-time relationships is essential in epidemic forecasting.展开更多
The overall teaching design for the junior middle school English unit aims to maximize the use of teaching resources by using the unit as the central theme,integrating it throughout all sections and related activities...The overall teaching design for the junior middle school English unit aims to maximize the use of teaching resources by using the unit as the central theme,integrating it throughout all sections and related activities.This approach continually reinforces students’understanding and retention of individual lesson content while fostering their core literacy and skills.It promotes a comprehensive development of students’listening,speaking,reading,and writing skills,allowing them to engage repeatedly with the language materials until they internalize them as part of their language proficiency.展开更多
Paste flow patterns and microscopic particle structures were studied in a pressurized environment generated by a pulse pump.Complex loop-pipe experiments and fluid-solid coupling-based simulations were conducted.The s...Paste flow patterns and microscopic particle structures were studied in a pressurized environment generated by a pulse pump.Complex loop-pipe experiments and fluid-solid coupling-based simulations were conducted.The scanning electron microscopy technique was also applied.Results revealed that flow resistance is closely related to pipeline curvature and angle in a complex pipe network.The vertical downward-straight pipe-inclined downward combination was adopted to effectively reduce the loss in resistance along with reducing the number of bends or increasing the radius of bend curvature.The maximum velocity ratio and velocity offset values could quantitatively characterize the influences of different pipeline layouts on the resistance.The correlation reached 96%.Particle distribution and interparticle forces affected flow resistance.Uniform particle states and weak interparticle forces were conducive to steady transport.Pulse pump pressure led to high flow resistance.It could improve pipe flow stability by increasing flow uniformity and particle motion stability.These results can contribute to safe and efficient paste filling.展开更多
Thermal transport properties of GaN heteroepitaxial structures are of critical importance for the thermal management of high-power GaN electronic and optoelectronic devices. Ultraviolet(UV) lasers are employed to dire...Thermal transport properties of GaN heteroepitaxial structures are of critical importance for the thermal management of high-power GaN electronic and optoelectronic devices. Ultraviolet(UV) lasers are employed to directly heat and sense the GaN epilayers in the transient thermoreflectance(TTR) measurement, obtaining important thermal transport properties in different GaN heterostructures, which include a diamond thin film heat spreader grown on GaN. The UV TTR technique enables rapid and non-contact thermal characterization for GaN wafers.展开更多
Immune checkpoint blockade(ICB)has achieved durable clinical responses and has significantly improved the overall survival of cancer patients1.Among the ICB agents,programmed death 1(PD-1)/programmed death ligand 1(PD...Immune checkpoint blockade(ICB)has achieved durable clinical responses and has significantly improved the overall survival of cancer patients1.Among the ICB agents,programmed death 1(PD-1)/programmed death ligand 1(PD-L1)antibodies are used to treat various human tumors by blocking PD-1/PD-L1 signaling.Impressive response rates with low autoimmune toxicity have been reported in 20%–30%of non-selected patients1;however,most patients fail to respond to PD-1/PD-L1 blockade or acquire resistance during therapy through unknown mechanisms1.展开更多
In this paper,a solidly mounted resonator(SMR)was designed with nanocrystalline diamond(NCD)as the high acoustic impedance material of Bragg reflector to improve the quality.We used Mathcad to investigate the effect o...In this paper,a solidly mounted resonator(SMR)was designed with nanocrystalline diamond(NCD)as the high acoustic impedance material of Bragg reflector to improve the quality.We used Mathcad to investigate the effect of the Bragg reflector on the performance of the SMR,as well as the influence of different materials and the number of layers of Bragg reflector on the quality factor Q.Results show that the Bragg reflector could reduce energy loss effectively,and the higher the impedance of the high acoustic impedance layer,the better the SMR.The parasitic factors of the SMR using two high acoustic impedance materials,tungsten(W)and NCD,were also simulated by an Advanced Design System(ADS)using the Mason model.It was found that the parasitic effect caused by metal would significantly decrease the Q factor of the SMR.In the frequency range below 6 GHz,within which the SMR works normally,NCD performed better than W.Therefore,NCD is a better choice of high acoustic impedance material in the design of the SMR,with improved quality at high frequency and low loss.The optimum number of layers of Bragg reflector is 6.展开更多
Warehousing and transferring strategies are an important part of business operations. The issue of optimal warehousing and transferring strategy is studied in this paper. Wal-Mart in Wuhan serves as an example to esta...Warehousing and transferring strategies are an important part of business operations. The issue of optimal warehousing and transferring strategy is studied in this paper. Wal-Mart in Wuhan serves as an example to establish a (s, S) random storage strategy model, a Markov chain model, and a nonlinear discrete programming model, aiming at maximizing the profit per cycle of every branch and further maximizing the company’s total profit per cycle. Among them, the random storage strategy model establishes a security zone of inventory for every branch, that is, it can meet consumers’ demand without spending too much storage costs. The Markov chain model is used to get the probability of losing sales opportunities in every branch. The nonlinear discrete programming model takes into account the horizontal transferring among branches, which further maximizes the company’s overall profit expectations. The three models above can be used to formulate inventory strategies, assess risks, and provide advice for every branch in order to form a complete storage ecosystem and provide constructive suggestions for the company’s operations.展开更多
Indium tin oxide(In_(2)O_(3)∶Sn)film is one of the most potential materials in the field of semiconductor industry.However,untreated In2O3∶Sn film has a low work function which can result in a high energy barrier th...Indium tin oxide(In_(2)O_(3)∶Sn)film is one of the most potential materials in the field of semiconductor industry.However,untreated In2O3∶Sn film has a low work function which can result in a high energy barrier that hinders the passage of carriers through the interface,thus leading to poor overall performance of directly prepared devices.In this study,crystalline transparent conductive In_(2)O_(3)∶Sn films were prepared by plasma exposure assisted magnetron sputtering under room temperature.Based on multiple testing methods,it can be found that the low temperature crystallization characteristics of In_(2)O_(3)∶Sn film were enhanced and the work function was effectively improved after Ar^(+)plasma exposure.The increase of the work function of In_(2)O_(3)∶Sn film was due to the increment of Sn⁃O bond on the surface brought by the transition from low oxidation state Sn^(2+)to high oxidation state Sn^(4+)under the action of high exposure.展开更多
A novel multispectral smart window has been proposed,which features dynamic modulation of light transmittance and effective shielding against electromagnetic microwave radiation.This design integrates liquid crystal d...A novel multispectral smart window has been proposed,which features dynamic modulation of light transmittance and effective shielding against electromagnetic microwave radiation.This design integrates liquid crystal dynamic scattering and dye doping techniques,enabling the dual regulation of transmittance and scattering within a singlelayer smart window.Additionally,the precise control of conductive film thickness ensures the attainment of robust microwave signal shielding.We present a theoretical model for ion movement in the presence of an alternating electric field,along with a novel approach to manipulate negative dielectric constant.The proposed model successfully enables a rapid transition between light transparent,absorbing and haze states,with an optimum drive frequency adjustable to approximately 300 Hz.Furthermore,the resistive design of the conductive layer effectively mitigates microwave radiation within the 2−18 GHz range.These findings offer an innovative perspective for future advancements in environmental construction.展开更多
With increasing demand for scratch-resistant flexible electro-nics,the development of transparent coatings with good scratch resistance and self-healing properties has emerged as a key research topic.In this study,a h...With increasing demand for scratch-resistant flexible electro-nics,the development of transparent coatings with good scratch resistance and self-healing properties has emerged as a key research topic.In this study,a high-strength self-healing poly(urethane-urea)(PUU)-based nanocomposite coating was prepared by introducing functionalized nanodiamond(ND)into a PUU matrix via solution blending.The PUU matrix had hard-segment repeating units and was constructed using iso-phorone diamine and isophorone isocyanate.The ND particles were modifed using a silane coupling agent,3-aminopropyl-triethoxysilane,to obtain well-dispersed KH-ND nanoparticles.KH-ND promoted microphase separation in the PU matrix,inducing the formation of dense and homogeneous hard domains that dissipated stress,prevented further crack devel-opment,and improved the mechanical properties and scratch resistance of the coating.In addition,the coating exhibited excellent self-healing properties.Fourier-transform infrared spectroscopy,scanning electron microscopy,and atomic force microscopy were used to characterize the self-healing and hardening mechanisms of the coating.The environmentally friendly PUU/KH-ND coating is easy to prepare and has broad application prospects in transparent and anti-scratch coatings for flexible electronics,automobiles,and home appliances.展开更多
In order to properly utilize the abundant CO_(2)and water resources,various catalytic materials have been developed to convert them into valuable chemicals as renewable fuels electrochemically or photochemically.Curre...In order to properly utilize the abundant CO_(2)and water resources,various catalytic materials have been developed to convert them into valuable chemicals as renewable fuels electrochemically or photochemically.Currently,most studies are conducted under mild laboratory conditions,but for some extreme environments,such as Mars and space stations,there is an urgent need to develop new catalysts satisfying such special requirements.Conventional catalytic materials mainly focus on metals and narrow bandgap semiconductor materials,while the research on wide and ultrawide bandgap materials that can inherently withstand extreme conditions has not received enough attention.Given the robust stability and excellent physico-chemical properties of diamond,it can be expected to perform in harsh environments for electrocatalysis or photocatalysis that has not been investigated thoroughly.Here,this review summarizes the catalytic functionality of diamond-based electrodes with various but tunable product selectivity to obtain the varied C_(1)or C_(2+)products,and discusses some important factors playing a key role in manipulating the catalytic activity.Moreover,the unique solvation electron effect of diamond gives it a significant advantage in photocatalytic conversions which is also summarized in this mini-review.In the end,prospects are made for the application of diamond-based catalysts under various extreme conditions.The challenges that may be faced in practical applications are also summarized and future breakthrough directions are proposed at the end.展开更多
Boron doped diamond(BDD)electrode is a promising electrochemical material for detecting dopamine level in the human’s body.In this work,we developed a new doping source-graphite and solid boron oxide powders to synth...Boron doped diamond(BDD)electrode is a promising electrochemical material for detecting dopamine level in the human’s body.In this work,we developed a new doping source-graphite and solid boron oxide powders to synthesize BDD film with microwave plasma chemical vapor deposition,so as to avoid using toxic or corrosive dopants,such as boroethane and trimethylborate.The synthesized BDD film is pinhole free and with high doping density of 8.44×10^20 cm^-3 calculated from the Raman spectroscopy.Subsequently,Au nanospheres were decorated on the surface of BDD film to improve electrochemical performance of the BDD film.The Au nanoparticles modified BDD electrode demonstrates an excellent electrochemical response,a high sensitivity(in the range of 5μM-1 m M),and a low detection limit(~0.8μM)for detecting dopamine.展开更多
Broadband response is pursued in both infrared(IR)and terahertz(THz)detection technologies,which find their applications in both terrestrial and astronomical realms.Herein,we report an ultrabroadband and multiband IR/...Broadband response is pursued in both infrared(IR)and terahertz(THz)detection technologies,which find their applications in both terrestrial and astronomical realms.Herein,we report an ultrabroadband and multiband IR/THz detector based on blocked-impurity-band detecting principle.The detectors are prepared by implanting phosphorus into germanium(Ge:P),where photoresponses with a P impurity band,a self-interstitial defect band,and a vacancy-P(V-P)pair defect band are realized simultaneously.The response spectra of the detectors show ultrabroad and dual response bands in a range of 3-28μm(IR band)and 40-165μm(THz band),respectively.Additionally,a tiny mid-IR(MIR)band within 3-4.2μm is embedded in the IR band.The THz band arises from the P impurity band,whereas the IR and the MIR bands are ascribed to the two defect bands.At150 m V and 4.5 K,the peak detectivities of the three bands are obtained as 2.9×10^(12) Jones(at 3.9μm),6.8×10^(12) Jones(at 16.3μm),and 9.9×10^(12) Jones(at 116.5μm),respectively.The impressive coverage andsensitivity of the detectors are promising for applications in IR and THz detection technologies.展开更多
With the development of optical technologies,transparent materials that provide protection from light have received considerable attention from scholars.As important channels for external light,windows play a vital ro...With the development of optical technologies,transparent materials that provide protection from light have received considerable attention from scholars.As important channels for external light,windows play a vital role in the regulation of light in buildings,vehicles,and aircrafts.There is a need for windows with switchable optical properties to prevent or attenuate damage or interference to the human eye and light-sensitive instruments by inappropriate optical radiation.In this context,liquid crystals(LCs),owing to their rich responsiveness and unique optical properties,have been considered among the best candidates for advanced light protection materials.In this review,we provide an overview of advances in research on LC-based methods for protection against light.First,we introduce the characteristics of different light sources and their protection requirements.Second,we introduce several classes of light modulation principles based on liquid crystal materials and demonstrate the feasibility of using them for light protection.In addition,we discuss current light protection strategies based on liquid crystal materials for different applications.Finally,we discuss the problems and shortcomings of current strategies.We propose several suggestions for the development of liquid crystal materials in the field of light protection.展开更多
In this study, the effects of oxygen flow rate and annealing temperature on Gd_2 O_3 structures and optical properties were systematically analyzed. Gd_2 O_3 films were deposited on both quartz and ZnS substrates by m...In this study, the effects of oxygen flow rate and annealing temperature on Gd_2 O_3 structures and optical properties were systematically analyzed. Gd_2 O_3 films were deposited on both quartz and ZnS substrates by magnetron sputtering and then annealed under vacuum at 700, 800 and 900℃, Restructure and phase transformation from cubic to monoclinic occur at different temperatures depending on the oxygen flow rate. The optical band gap, which is more sensitive to the annealing temperature than oxygen flow rate changes from 5.32 to 5.65 eV. The refractive index is approximately 1.75 at 550 nm and is adjustable by the oxygen flow rate. The transmittance of the ZnS substrate with Gd_2 O_3 film exceeds 80% and reaches82% at the 7.5-9.5 μm range. When ZnS is coated on both sides, the transmittance is increased to approximately 90%. Our results indicate that Gd_2 O_3 films are promising new candidates for anti-reflective coatings in the infrared region.展开更多
Both absorption and diffuse reflection can effectively suppress microwave backward reflection.However,the challenge of designing wideband absorptive elements with anti-phase reflection hinders the simultaneous working...Both absorption and diffuse reflection can effectively suppress microwave backward reflection.However,the challenge of designing wideband absorptive elements with anti-phase reflection hinders the simultaneous working of the two principles.With aid of the wideband characteristic of bilateral complementary structure,we propose a strategy to design wideband absorptive elements with large reflection phase differences.For proof of concept,the proposed elements are arranged in a rectangular grid by optimizing scattering field distribution.The proposed diffusion metabsorber achieves over 20-dB scattering field reduction in the range of 8.5–20.3 GHz with good polarization stability and high angular insensitivity of up to±40°,which has been verified by real experiments.Furthermore,the proposed design strategy exhibits the potential to further reduce electromagnetic wave reflection,and the optical transparent characteristic is promising for window applications.展开更多
基金Youth Innovation Promotion Association CAS,Grant/Award Number:2021103Strategic Priority Research Program of Chinese Academy of Sciences,Grant/Award Number:XDC02060500。
文摘Appropriately characterising the mixed space-time relations of the contagion process caused by hybrid space and time factors remains the primary challenge in COVID-19 forecasting.However,in previous deep learning models for epidemic forecasting,spatial and temporal variations are captured separately.A unified model is developed to cover all spatio-temporal relations.However,this measure is insufficient for modelling the complex spatio-temporal relations of infectious disease transmission.A dynamic adaptive spatio-temporal graph network(DASTGN)is proposed based on attention mechanisms to improve prediction accuracy.In DASTGN,complex spatio-temporal relations are depicted by adaptively fusing the mixed space-time effects and dynamic space-time dependency structure.This dual-scale model considers the time-specific,space-specific,and direct effects of the propagation process at the fine-grained level.Furthermore,the model characterises impacts from various space-time neighbour blocks under time-varying interventions at the coarse-grained level.The performance comparisons on the three COVID-19 datasets reveal that DASTGN achieves state-of-the-art results with a maximum improvement of 17.092%in the root mean-square error and 11.563%in the mean absolute error.Experimental results indicate that the mechanisms of designing DASTGN can effectively detect some spreading characteristics of COVID-19.The spatio-temporal weight matrices learned in each proposed module reveal diffusion patterns in various scenarios.In conclusion,DASTGN has successfully captured the dynamic spatio-temporal variations of COVID-19,and considering multiple dynamic space-time relationships is essential in epidemic forecasting.
文摘The overall teaching design for the junior middle school English unit aims to maximize the use of teaching resources by using the unit as the central theme,integrating it throughout all sections and related activities.This approach continually reinforces students’understanding and retention of individual lesson content while fostering their core literacy and skills.It promotes a comprehensive development of students’listening,speaking,reading,and writing skills,allowing them to engage repeatedly with the language materials until they internalize them as part of their language proficiency.
基金financially supported by the National Natural Science Foundation of China (No.52074137)Yunnan Fundamental Research Projects (No.202201AT070151)+1 种基金Yunnan Major Scientific and Technological Projects (No.202202AG050014)Yunnan Innovation Team (No.202105AE160023)。
文摘Paste flow patterns and microscopic particle structures were studied in a pressurized environment generated by a pulse pump.Complex loop-pipe experiments and fluid-solid coupling-based simulations were conducted.The scanning electron microscopy technique was also applied.Results revealed that flow resistance is closely related to pipeline curvature and angle in a complex pipe network.The vertical downward-straight pipe-inclined downward combination was adopted to effectively reduce the loss in resistance along with reducing the number of bends or increasing the radius of bend curvature.The maximum velocity ratio and velocity offset values could quantitatively characterize the influences of different pipeline layouts on the resistance.The correlation reached 96%.Particle distribution and interparticle forces affected flow resistance.Uniform particle states and weak interparticle forces were conducive to steady transport.Pulse pump pressure led to high flow resistance.It could improve pipe flow stability by increasing flow uniformity and particle motion stability.These results can contribute to safe and efficient paste filling.
基金Project supported by the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.61604049)the Shenzhen Municipal Research Project(Grant No.JCYJ20160531192714636)
文摘Thermal transport properties of GaN heteroepitaxial structures are of critical importance for the thermal management of high-power GaN electronic and optoelectronic devices. Ultraviolet(UV) lasers are employed to directly heat and sense the GaN epilayers in the transient thermoreflectance(TTR) measurement, obtaining important thermal transport properties in different GaN heterostructures, which include a diamond thin film heat spreader grown on GaN. The UV TTR technique enables rapid and non-contact thermal characterization for GaN wafers.
基金supported by the National Nature Science Foundation(Grant Nos.82150115,82025027,and 32000517)the National Key R&D Program of China(Grant No.2022YFA1105200).
文摘Immune checkpoint blockade(ICB)has achieved durable clinical responses and has significantly improved the overall survival of cancer patients1.Among the ICB agents,programmed death 1(PD-1)/programmed death ligand 1(PD-L1)antibodies are used to treat various human tumors by blocking PD-1/PD-L1 signaling.Impressive response rates with low autoimmune toxicity have been reported in 20%–30%of non-selected patients1;however,most patients fail to respond to PD-1/PD-L1 blockade or acquire resistance during therapy through unknown mechanisms1.
基金Sponsored by the National Science Fund for Distinguished Young Scholars(Grant No.51625201)the National Natural Science Foundation of China(Grant No.51702066).
文摘In this paper,a solidly mounted resonator(SMR)was designed with nanocrystalline diamond(NCD)as the high acoustic impedance material of Bragg reflector to improve the quality.We used Mathcad to investigate the effect of the Bragg reflector on the performance of the SMR,as well as the influence of different materials and the number of layers of Bragg reflector on the quality factor Q.Results show that the Bragg reflector could reduce energy loss effectively,and the higher the impedance of the high acoustic impedance layer,the better the SMR.The parasitic factors of the SMR using two high acoustic impedance materials,tungsten(W)and NCD,were also simulated by an Advanced Design System(ADS)using the Mason model.It was found that the parasitic effect caused by metal would significantly decrease the Q factor of the SMR.In the frequency range below 6 GHz,within which the SMR works normally,NCD performed better than W.Therefore,NCD is a better choice of high acoustic impedance material in the design of the SMR,with improved quality at high frequency and low loss.The optimum number of layers of Bragg reflector is 6.
文摘Warehousing and transferring strategies are an important part of business operations. The issue of optimal warehousing and transferring strategy is studied in this paper. Wal-Mart in Wuhan serves as an example to establish a (s, S) random storage strategy model, a Markov chain model, and a nonlinear discrete programming model, aiming at maximizing the profit per cycle of every branch and further maximizing the company’s total profit per cycle. Among them, the random storage strategy model establishes a security zone of inventory for every branch, that is, it can meet consumers’ demand without spending too much storage costs. The Markov chain model is used to get the probability of losing sales opportunities in every branch. The nonlinear discrete programming model takes into account the horizontal transferring among branches, which further maximizes the company’s overall profit expectations. The three models above can be used to formulate inventory strategies, assess risks, and provide advice for every branch in order to form a complete storage ecosystem and provide constructive suggestions for the company’s operations.
基金Sponsored by the National Science Fund for Distinguished Young Scholars of China(Grant No.51625201).
文摘Indium tin oxide(In_(2)O_(3)∶Sn)film is one of the most potential materials in the field of semiconductor industry.However,untreated In2O3∶Sn film has a low work function which can result in a high energy barrier that hinders the passage of carriers through the interface,thus leading to poor overall performance of directly prepared devices.In this study,crystalline transparent conductive In_(2)O_(3)∶Sn films were prepared by plasma exposure assisted magnetron sputtering under room temperature.Based on multiple testing methods,it can be found that the low temperature crystallization characteristics of In_(2)O_(3)∶Sn film were enhanced and the work function was effectively improved after Ar^(+)plasma exposure.The increase of the work function of In_(2)O_(3)∶Sn film was due to the increment of Sn⁃O bond on the surface brought by the transition from low oxidation state Sn^(2+)to high oxidation state Sn^(4+)under the action of high exposure.
基金the financial supports from the National Key Research and Development Program of China(Grant No.2023YFB3811600)the National Science Fund for Distinguished Young Scholars(Grant No.51625201)+6 种基金State Key Program of National Natural Science of China(Grant No.52032004)National Youth Science Funds of China(Grant No.52102039)Key Research and Development Program of Heilongjiang Province(Grant No.GA21D001,2022ZX06C05)the Fundamental Research Funds for the Central Universities(Grant No.HIT.OCEF.2022011)the Major Program of Harbin Institute of Technology(Grant NO.2023FRFK01002)the Fundamental Research Funds for the Central Universities(2022FRFK060026)the National Youth Science Funds of China(Grant No.52302172).
文摘A novel multispectral smart window has been proposed,which features dynamic modulation of light transmittance and effective shielding against electromagnetic microwave radiation.This design integrates liquid crystal dynamic scattering and dye doping techniques,enabling the dual regulation of transmittance and scattering within a singlelayer smart window.Additionally,the precise control of conductive film thickness ensures the attainment of robust microwave signal shielding.We present a theoretical model for ion movement in the presence of an alternating electric field,along with a novel approach to manipulate negative dielectric constant.The proposed model successfully enables a rapid transition between light transparent,absorbing and haze states,with an optimum drive frequency adjustable to approximately 300 Hz.Furthermore,the resistive design of the conductive layer effectively mitigates microwave radiation within the 2−18 GHz range.These findings offer an innovative perspective for future advancements in environmental construction.
基金supported by the Fundamental Research Funds for the Central Universities[Grant No.HIT.0CEF.2022011]National Science Fund for Distinguished Young Scholars[Grant No.51625201]+1 种基金National Youth Science Funds of China[Grant No.52102039]Key Research and Development Program of Heilongjiang Province[Grant No.GA21D001,2022ZX06C05].
文摘With increasing demand for scratch-resistant flexible electro-nics,the development of transparent coatings with good scratch resistance and self-healing properties has emerged as a key research topic.In this study,a high-strength self-healing poly(urethane-urea)(PUU)-based nanocomposite coating was prepared by introducing functionalized nanodiamond(ND)into a PUU matrix via solution blending.The PUU matrix had hard-segment repeating units and was constructed using iso-phorone diamine and isophorone isocyanate.The ND particles were modifed using a silane coupling agent,3-aminopropyl-triethoxysilane,to obtain well-dispersed KH-ND nanoparticles.KH-ND promoted microphase separation in the PU matrix,inducing the formation of dense and homogeneous hard domains that dissipated stress,prevented further crack devel-opment,and improved the mechanical properties and scratch resistance of the coating.In addition,the coating exhibited excellent self-healing properties.Fourier-transform infrared spectroscopy,scanning electron microscopy,and atomic force microscopy were used to characterize the self-healing and hardening mechanisms of the coating.The environmentally friendly PUU/KH-ND coating is easy to prepare and has broad application prospects in transparent and anti-scratch coatings for flexible electronics,automobiles,and home appliances.
基金Basic and Applied Basic Research Foundation of Guangdong Province,Grant/Award Number:2022A1515011794Shenzhen Constantly-Supported Project for Universities and Colleges,Grant/Award Number:GXWD20231130110722002National Natural Science Foundation of China,Grant/Award Number:52102162。
文摘In order to properly utilize the abundant CO_(2)and water resources,various catalytic materials have been developed to convert them into valuable chemicals as renewable fuels electrochemically or photochemically.Currently,most studies are conducted under mild laboratory conditions,but for some extreme environments,such as Mars and space stations,there is an urgent need to develop new catalysts satisfying such special requirements.Conventional catalytic materials mainly focus on metals and narrow bandgap semiconductor materials,while the research on wide and ultrawide bandgap materials that can inherently withstand extreme conditions has not received enough attention.Given the robust stability and excellent physico-chemical properties of diamond,it can be expected to perform in harsh environments for electrocatalysis or photocatalysis that has not been investigated thoroughly.Here,this review summarizes the catalytic functionality of diamond-based electrodes with various but tunable product selectivity to obtain the varied C_(1)or C_(2+)products,and discusses some important factors playing a key role in manipulating the catalytic activity.Moreover,the unique solvation electron effect of diamond gives it a significant advantage in photocatalytic conversions which is also summarized in this mini-review.In the end,prospects are made for the application of diamond-based catalysts under various extreme conditions.The challenges that may be faced in practical applications are also summarized and future breakthrough directions are proposed at the end.
基金financially supported by the National Science Fund for Distinguished Young Scholars(No.51625201)the National Natural Science Foundation of China No.51,702,066+2 种基金the National Key Research and Development Program of China(No.2016YFE0201600)the Key Laboratory of Micro-systems and Micro-structures Manufacturing,Ministry of Education,Harbin Institute of Technology(No.2016KM001)the Innovative research group of NSFC11421091。
文摘Boron doped diamond(BDD)electrode is a promising electrochemical material for detecting dopamine level in the human’s body.In this work,we developed a new doping source-graphite and solid boron oxide powders to synthesize BDD film with microwave plasma chemical vapor deposition,so as to avoid using toxic or corrosive dopants,such as boroethane and trimethylborate.The synthesized BDD film is pinhole free and with high doping density of 8.44×10^20 cm^-3 calculated from the Raman spectroscopy.Subsequently,Au nanospheres were decorated on the surface of BDD film to improve electrochemical performance of the BDD film.The Au nanoparticles modified BDD electrode demonstrates an excellent electrochemical response,a high sensitivity(in the range of 5μM-1 m M),and a low detection limit(~0.8μM)for detecting dopamine.
基金National Natural Science Foundation of China(11933006,61775229,61805060,61927813)Key Research and Development Program of Zhejiang Province(2020C01120)Sino-German Science Center(GZ1580)。
文摘Broadband response is pursued in both infrared(IR)and terahertz(THz)detection technologies,which find their applications in both terrestrial and astronomical realms.Herein,we report an ultrabroadband and multiband IR/THz detector based on blocked-impurity-band detecting principle.The detectors are prepared by implanting phosphorus into germanium(Ge:P),where photoresponses with a P impurity band,a self-interstitial defect band,and a vacancy-P(V-P)pair defect band are realized simultaneously.The response spectra of the detectors show ultrabroad and dual response bands in a range of 3-28μm(IR band)and 40-165μm(THz band),respectively.Additionally,a tiny mid-IR(MIR)band within 3-4.2μm is embedded in the IR band.The THz band arises from the P impurity band,whereas the IR and the MIR bands are ascribed to the two defect bands.At150 m V and 4.5 K,the peak detectivities of the three bands are obtained as 2.9×10^(12) Jones(at 3.9μm),6.8×10^(12) Jones(at 16.3μm),and 9.9×10^(12) Jones(at 116.5μm),respectively.The impressive coverage andsensitivity of the detectors are promising for applications in IR and THz detection technologies.
基金supported by the following grants:Key Project of National Natural Science Foundation of China(Grant No.52032004)National Natural Science Foundation for Distinguished Young Scholars of China(Grant No.51625201)+4 种基金National Natural Science Funds of China(Grant No.52102039)China Postdoctoral Science Foundation(Grant No.2021M700036)The Open Fund of State Key Laboratory of Advanced Welding and Joining(Grant No.AWJ-22Z04)National Defense Supporting Scientific Research Projects(186)Keypoint Research and Invention Program of Heilongjiang Province(GA21D001).
文摘With the development of optical technologies,transparent materials that provide protection from light have received considerable attention from scholars.As important channels for external light,windows play a vital role in the regulation of light in buildings,vehicles,and aircrafts.There is a need for windows with switchable optical properties to prevent or attenuate damage or interference to the human eye and light-sensitive instruments by inappropriate optical radiation.In this context,liquid crystals(LCs),owing to their rich responsiveness and unique optical properties,have been considered among the best candidates for advanced light protection materials.In this review,we provide an overview of advances in research on LC-based methods for protection against light.First,we introduce the characteristics of different light sources and their protection requirements.Second,we introduce several classes of light modulation principles based on liquid crystal materials and demonstrate the feasibility of using them for light protection.In addition,we discuss current light protection strategies based on liquid crystal materials for different applications.Finally,we discuss the problems and shortcomings of current strategies.We propose several suggestions for the development of liquid crystal materials in the field of light protection.
基金supported by the National Science Fund for Distinguished Young Scholars(51625201)National Key Research and Development Program of China(2016YFE0201600)+3 种基金National Natural Science Foundation of China(51372053)Innovative Research Group of National Natural Science Foundation of China(11421091)International Science&Technology Cooperation Program of China(2015DFR50300)the Major State Basic Search Program(2014CB46505)
文摘In this study, the effects of oxygen flow rate and annealing temperature on Gd_2 O_3 structures and optical properties were systematically analyzed. Gd_2 O_3 films were deposited on both quartz and ZnS substrates by magnetron sputtering and then annealed under vacuum at 700, 800 and 900℃, Restructure and phase transformation from cubic to monoclinic occur at different temperatures depending on the oxygen flow rate. The optical band gap, which is more sensitive to the annealing temperature than oxygen flow rate changes from 5.32 to 5.65 eV. The refractive index is approximately 1.75 at 550 nm and is adjustable by the oxygen flow rate. The transmittance of the ZnS substrate with Gd_2 O_3 film exceeds 80% and reaches82% at the 7.5-9.5 μm range. When ZnS is coated on both sides, the transmittance is increased to approximately 90%. Our results indicate that Gd_2 O_3 films are promising new candidates for anti-reflective coatings in the infrared region.
基金Key Project of National Natural Science Foundation of China(52032004)National Natural Science Foundation for Distinguished Young Scholars of China(51625201)Shanghai Pujiang Program(20PJ1411400)。
文摘Both absorption and diffuse reflection can effectively suppress microwave backward reflection.However,the challenge of designing wideband absorptive elements with anti-phase reflection hinders the simultaneous working of the two principles.With aid of the wideband characteristic of bilateral complementary structure,we propose a strategy to design wideband absorptive elements with large reflection phase differences.For proof of concept,the proposed elements are arranged in a rectangular grid by optimizing scattering field distribution.The proposed diffusion metabsorber achieves over 20-dB scattering field reduction in the range of 8.5–20.3 GHz with good polarization stability and high angular insensitivity of up to±40°,which has been verified by real experiments.Furthermore,the proposed design strategy exhibits the potential to further reduce electromagnetic wave reflection,and the optical transparent characteristic is promising for window applications.
