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Visual measurement of the microscopic temperature of porous graphene based on cholesteric liquid crystal microcapsules

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Chinese Optics Letters 2020年第3期18卷 27-30页

作者： Haoyan Jiang Yaoyi Tang xiaohan zeng Ruiwen Xiao Peng Lü Lei Wang Yanqing Lu College of Electronic and Optical Engineering&College of Microelectronics Nanjing University of Posts and TelecommunicationsNanjing 210023China National Laboratory of Solid State Microstructures Key Laboratory of Intelligent Optical Sensing and Manipulationand College of Engineering and Applied SciencesNanjing UniversityNanjing 210093China

Measuring the microscopic temperature of graphene is *** used cholesteric liquid crystal microcapsules(CLCMs)as temperature sensors to detect the local temperature of three-dimensional porous graphene through quantitative *** on a CLCM(~20μm in size),we determined the temperature variation in a small area with an accuracy of 0.1℃.By analyzing the color changes between two CLCMs,we demonstrated the temperature changes dynamically in a region with a diameter of approximately 110μ***,by comparing the color evolution among the three CLCMs,we visualized the anisotropic thermal properties in the *** convenient and low-cost temperature measurement method is expected to further improve graphene-based devices.

关键词： porous graphene cholesteric liquid crystal microcapsule microscopic temperature visual measurement

Learning to optimize:A tutorial for continuous and mixed-integer optimization

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Science China Mathematics 2024年第6期67卷 1191-1262页

作者： xiaohan Chen Jialin Liu Wotao Yin Decision Intelligence Lab Alibaba DAMO AcademyBellevueWA98004USA

Learning to optimize(L2O)stands at the intersection of traditional optimization and machine learning,utilizing the capabilities of machine learning to enhance conventional optimization *** real-world optimization problems frequently share common structures,L2O provides a tool to exploit these structures for better or faster *** tutorial dives deep into L2O techniques,introducing how to accelerate optimization algorithms,promptly estimate the solutions,or even reshape the optimization problem itself,making it more adaptive to real-world *** considering the prerequisites for successful applications of L2O and the structure of the optimization problems at hand,this tutorial provides a comprehensive guide for practitioners and researchers alike.

关键词： AI for mathematics(AI4Math) learning to optimize algorithm unrolling plug-and-play methods differentiable programming machine learning for combinatorial optimization(ML4CO)

Epidemiological features of seasonal influenza transmission among 11 climate zones in Chinese mainland

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Infectious Diseases of Poverty 2024年第1期13卷 27-41页

作者： xiaohan Si Liping Wang Kerrie Mengersen Wenbiao Hu Ecosystem Change and Population Health Research Group School of Public Health and Social WorkQueensland University of TechnologyBrisbaneQLD 4059Australia Information Center Chinese Center for Disease Control and PreventionBeijing 102206China School of Mathematical Sciences Queensland University of TechnologyBrisbaneQLD 4000Australia

Background Previous studies provided some evidence of meteorological factors influence seasonal influenza transmission patterns varying across regions and latitudes. However, research on seasonal influenza activities based on climate zones are still in lack. This study aims to utilize the ecological-based Koppen Geiger climate zones classification system to compare the spatial and temporal epidemiological characteristics of seasonal influenza in Chinese mainland and assess the feasibility of developing an early warning *** Weekly influenza cases number from 2014 to 2019 at the county and city level were sourced from China National Notifiable Infectious Disease Report Information System. Epidemic temporal indices, time series seasonality decomposition, spatial modelling theories including Moran’s/ and local indicators of spatial association were applied to identify the spatial and temporal patterns of influenza *** All climate zones had peaks in Winter-Spring season. Arid, desert, cold (BWk) showed up the first peak. Only Tropical, savannah (Aw) and Temperate, dry winter with hot summer (Cwa) zones had unique summer peak. Temperate, no dry season and hot summer (Cfa) zone had highest average incidence rate (IR) at 1.047/100,000. The Global Moran’s/ showed that average IR had significant clustered trend (z = 53.69,P < 0.001), with local Moran’s/ identified high-high cluster in Cfa and Cwa. IR differed among three age groups between climate zones (0-14 years old:F = 26.80,P < 0.001;15-64 years old:F = 25.04,P < 0.001;Above 65 years old:F = 5.27,P < 0.001). Age group 0-14 years had highest average IR in Cwa and Cfa (IR= 6.23 and 6.21) with unique dual peaks in winter and spring season showed by seasonality *** Seasonal influenza exhibited distinct spatial and temporal patterns in different climate zones. Seasonal influenza primarily emerged in BWk, subsequently in Cfa and Cwa. Cfa, Cwa and BSk pose high risk for seasonal

关键词： Seasonal influenza Koppen Geiger climate zones classification system Chinese mainland Seasonality decomposition Local indicators of spatial association

Improved Diurnal Cycle of Precipitation on Land in a Global Non-Hydrostatic Model Using a Revised NSAS Deep Convective Scheme

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Advances in Atmospheric Sciences 2024年第6期41卷 1217-1234页

作者： Yifan ZHAO Xindong PENG xiaohan LI Siyuan CHEN State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China University of Chinese Academy of Sciences Beijing 100049China CMA Earth System modeling and Prediction Centre Beijing 100081China 2035 Future Laboratory PIESAT Information Technology Co Ltd.Beijing 100195China

In relatively coarse-resolution atmospheric models,cumulus parameterization helps account for the effect of subgridscale convection,which produces supplemental rainfall to the grid-scale precipitation and impacts the diurnal cycle of *** this study,the diurnal cycle of precipitation was studied using the new simplified Arakawa-Schubert scheme in a global non-hydrostatic atmospheric model,i.e.,the Yin-Yang-grid Unified Model for the *** new diagnostic closures and a convective trigger function were suggested to emphasize the job of the cloud work function corresponding to the free tropospheric large-scale *** results of the 0.25-degree model in 3-month batched real-case simulations revealed an improvement in the diurnal precipitation variation by using a revised trigger function with an enhanced dynamical constraint on the convective initiation and a suitable threshold of the *** reducing the occurrence of convection during peak solar radiation hours,the revised scheme was shown to be effective in delaying the appearance of early-afternoon rainfall peaks over most land areas and accentuating the nocturnal peaks that were wrongly concealed by the more substantial afternoon *** addition,the revised scheme enhanced the simulation capability of the precipitation probability density function,such as increasing the extremely low-and high-intensity precipitation events and decreasing small and moderate rainfall events,which contributed to the reduction of precipitation bias over mid-latitude and tropical land areas.

关键词： cumulus parameterization diurnal cycle of precipitation large-scale dynamic forcing global non-hydrostatic atmospheric model performance verification

Low-permittivity LiLn(PO_(3))_(4)(Ln=La,Sm,Eu)dielectric ceramics for microwave/millimeter-wave communication

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Journal of Advanced Ceramics 2024年第5期13卷 602-620页

作者： Huanrong Tian xiaohan Zhang Zidong Zhang Yao Liu Haitao Wu Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan 250061China School of Materials Science and Engineering Shandong UniversityJinan 250061China School of Environmental and Material Engineering Yantai UniversityYantai 264005China

The development of dielectric materials with low permittivity and low loss is a great challenge in wireless *** this study,LiLn(PO_(3))_(4)(Ln=La,Sm,Eu)ceramic systems were successfully prepared using the traditional solid-state method.X-ray diffraction analysis indicated that the LiLn(PO_(3))_(4)ceramics crystallized in a monoclinic structure when sintered at 850–940℃.The characteristic peak shifted to higher angles with variations in the Ln element,which was ascribed to a reduction in the cell *** analysis by structure refinement revealed that the reduction in the cell volume resulted from the decrease in chemical bond lengths and the compression of[LiO_(4)]and[PO_(4)]***,the LiLn(PO_(3))_(4)ceramic system displayed exceptional performance at low sintering temperatures(910–925℃),including a high quality factor(Q·f)of 41,607–75,968 GHz,low temperature coefficient of resonant frequency(τ_(f))ranging from−19.64 to−47.49 ppm/℃,low permittivity(ε_(r))between 5.04 and 5.26,and low density(3.04–3.26 g/cm^(3)).The application of Phillips–van Vechten–Levine(P–V–L)theory revealed that the increased Q·f value of the LiLn(PO_(3))_(4)systems can be attributed to the enhanced packing fraction,bond covalency,and lattice energy,and the stability of τ_(f) was associated with the increase in the bond ***,a prototype microstrip patch antenna using LiEu(PO_(3))_(4) ceramics was *** measurement results demonstrated excellent antenna performance with a bandwidth of 360 MHz and a peak gain of 5.11 dB at a central frequency of 5.08 ***,low-εr LiLn(PO_(3))_(4)ceramic systems are promising candidates for microwave/millimeter-wave communication.

关键词： low permittivity LiLn(PO_(3))_(4) microwave dielectric properties Phillips-van Vechten-Levine(P-V-L)theory microstrip patch antenna

An advanced 2D/3D g-C_(3)N_(4)/TiO_(2)@MnO_(2) multifunctional membrane for sunlight-driven sustainable water purification

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Nano Research 2024年第4期17卷 2368-2380页

作者： Fan Yu Chunjia Luo xiaohan Niu Min Chao Pengfei Zhang Luke Yan Polymer Materials&Engineering Department School of Materials Science&EngineeringChang’an UniversityXi’an 710064China Key Laboratory of Road Construction Technology and Equipment MOEChang’an UniversityXi’an 710064China School of Textile Science and Engineering Xi’an Polytechnic UniversityXi’an 710064China

Graphitic carbon nitride(g-C_(3)N_(4))nanosheets have attracted widespread interest in the construction of advanced separation ***,dense stacking and a single functionality have limited the membrane ***,an advanced two-/three-dimensional(2D/3D)g-C_(3)N_(4)/TiO_(2)@MnO_(2) membrane is constructed by intercalating 3D TiO_(2)@MnO_(2) nanostructures into g-C_(3)N_(4) *** 3D flower-like nanostructures broaden the transport channels of the composite *** membrane can effectively separate five oil-in-water(O/W)emulsions,with a maximum flux of 3265.67±15.01 L·m^(-2)·h^(-1)·bar^(-1) and a maximum efficiency of 99.69%±0.45%for toluene-in-water emulsion(T/W).Meanwhile,the TiO_(2)@MnO_(2) acts as an excellent electron acceptor and provides positive spatial separation of electrons–holes(e^(-)–h^(+)).The formation of 2D/3D heterojunctions allows the material with wider light absorption and smaller bandgap(2.10 eV).These photoelectric properties give the membrane good degradation of three different pollutants,with about 100%degradation for methylene blue(MB)and malachite green(MG).The photocatalytic antibacterial efficiency of the membrane is also about 100%.After cyclic experiment,the membrane maintains its original separation and photocatalytic *** remarkable multifunctional and self-cleaning properties of the g-C_(3)N_(4) based membrane represent its potential value for complex wastewater treatment.

关键词： graphitic carbon nitride(g-C_(3)N_(4))based membrane three-dimensional(3D)nanostructures self-cleaning multifunction

Stability of bedded rock slopes subjected to hydro-fluctuation and associated strength deterioration

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3233-3257页

作者： Bin Xu Xinrong Liu Yue Liang xiaohan Zhou Zuliang Zhong School of River and Ocean Engineering Chongqing Jiaotong UniversityChongqing400074China School of Civil Engineering Chongqing UniversityChongqing400045China

Reservoir-induced earthquakes(RIEs)occur frequently in the Three Gorges Reservoir Area(TGRA)and the rock mass strength of the hydro-fluctuation belt(HFB)deteriorates severely due to the reservoirinduced seismic *** models of typical bedded rock slopes(BRSs),***(GIS),moderately(MIS),and steeply(SIS)inclined slopes,were proposed according to field *** dynamic response mechanism and stability of the BRSs,affected by the rock mass deterioration of the HFB,were investigated by the shaking table test and the universal distinct element code(UDEC)***,the amplification coefficient of the peak ground acceleration(PGA)of the slope was gradually attenuated under multiple seismic loads,and the acceleration response showed obvious“surface effect”and“elevation effect”in the horizontal and vertical directions,***“S-type”cubic function and“steep-rise type”exponential function were used to characterize the cumulative damage evolution of the slope caused by microseismic waves(low seismic waves)and high seismic waves,*** to the dynamic responses of the acceleration,cumulative displacement,rock pressure,pore water pressure,damping ratio,natural frequency,stability coefficient,and sliding velocity of the slope,the typical evolution processes of the dynamic cumulative damage and instability failure of the slope were generalized,and the numerical and experimental results were *** the dynamic effects of the slope height(SH),slope angle(SA),bedding plane thickness(BPT),dip angle of the bedding plane(DABP),dynamic load amplitude(DLA),dynamic load frequency(DLF),height of water level of the hydro-fluctuation belt(HWLHFB),degradation range of the hydro-fluctuation belt(DRHFB),and degradation shape of the hydro-fluctuation belt(DSHFB),the sensitivity of factors influencing the slope dynamic stability using the orthogonal analysis method(OAM)was DLA>DRHFB>SA>SH>DLF>HWLHFB>DSHFB>DABP>BPT.

关键词： Bedded rock slopes Hydro-fluctuation belt Shaking table test UDEC simulation Dynamic response mechanism

Stochastic Gradient Compression for Federated Learning over Wireless Network

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China Communications 2024年第4期21卷 230-247页

作者： Lin xiaohan Liu Yuan Chen Fangjiong Huang Yang Ge Xiaohu School of Electronic and Information Engineering South China University of TechnologyGuangzhou 510641China Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016China School of Electronic Information and Communications Huazhong University of Science and TechnologyWuhan 430074China

As a mature distributed machine learning paradigm,federated learning enables wireless edge devices to collaboratively train a shared AI-model by stochastic gradient descent(SGD).However,devices need to upload high-dimensional stochastic gradients to edge server in training,which cause severe communication *** address this problem,we compress the communication by sparsifying and quantizing the stochastic gradients of edge *** first derive a closed form of the communication compression in terms of sparsification and quantization ***,the convergence rate of this communicationcompressed system is analyzed and several insights are ***,we formulate and deal with the quantization resource allocation problem for the goal of minimizing the convergence upper bound,under the constraint of multiple-access channel *** show that the proposed scheme outperforms the benchmarks.

关键词： federated learning gradient compression quantization resource allocation stochastic gradient descent(SGD)

Advancements in S-scheme heterojunction materials for photocatalytic environmental remediation

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Journal of Materials Science & Technology 2024年第2期169卷 182-198页

作者： Changliang Nie xiaohan Wang Ping Lu Yukun Zhu Xin Li Hua Tang School of Environmental Science and Engineering State Key Laboratory of Bio-fibers and Eco-textilesQingdao UniversityQingdao266071China Institute of Biomass Engineering Key Laboratory of Energy Plants Resource and UtilizationMinistry of Agriculture and Rural AffairsSouth China Agricultural UniversityGuangzhou510642China School of Environmental Science and Engineering Shandong UniversityQingdao266237China

Recently,S-scheme heterojunctions have gained considerable attention in the field of photocatalytic environmental remediation as their potential to achieve efficient spatial charge separation coupled with strong redox ***,this review provides an overview of the current state-of-the-art in the development of S-scheme-based photocatalysts for the purification of environmental *** review first covers the fundamentals of heterogeneous photocatalysis for environmental ***,an introduction to the background,mechanism,design principles,and characterization techniques of S-scheme heterojunctions is ***,the review presents a comparison and summary of using various S-scheme photocatalysts for the removal of several target pollutants,such as bacteria,heavy metals,nitrogen oxides,antibiotics,and ***,the modification strategies of S-scheme heterojunction photocatalysts are also ***,a brief discussion of the challenges and prospects associated with S-scheme photocatalytic systems is demonstrated.

关键词： S-scheme heterojunctions Photocatalyst Pollutant Environmental remediation