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Climatic impacts induced by winter wheat irrigation over North China simulated by the nonhydrostatic RegCM4.7

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Advances in Climate Change Research 2024年第2期15卷 197-210页

作者： jia.WU zhen-Yu HAN Xue-Jie GAO zheng-jia.LIU National Climate Centre China Meteorological AdministrationBeijing 100081China Key Laboratory for Climate Studies China Meteorological AdministrationBeijing 100081China Climate Change Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjing 210044China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China

Quantification of the impact of winter wheat irrigation on the climate and the occurrence of extreme climatic events over North China is crucial for regional adaptation *** related studies mainly focused on the impact on surface processes;however,few focused on the effects of extreme events using high-resolution nonhydrostatic regional climate ***,the 9-km-resolution nonhydrostatic RegCM4.7 was coupled with a crop irrigation scheme and an updated winter wheat irrigation dataset to better simulate irrigation *** experiments were conducted with and without winter wheat irrigation to isolate the effects of *** showed that irrigation simulation reduces the model biases in temperature,precipitation,latent heat flux,soil moisture,sensitive heat flux,and top-layer soil ***,it also reduces the bias and increases the correlation with observations obtained in irrigated areas,especially in summer,indicating better representation of irrigation *** wheat irrigation tends to cause substantial cooling of the local surface maximum,minimum,and mean air temperatures(by-1.68,-0.34,and-0.79℃,respectively)over irrigated areas of North China,with the largest changes observed in relation to maximum ***,precipitation is found to increase during spring and summer,which is strongly related to water vapor transport in the lower levels of the *** analyses indicated that the number of annual mean hot days decrease(-13.9 d),whereas the number of both comfort days(+10.2 d)and rainy days(days with total precipitation greater than 1 mm:+6.6 d)increase over irrigated areas,demonstrating beneficial feedback to human perception and ***,although the heat wave risk increases(number of annual mean heat wave days:+5.8 d),the impact is limited to small areas within irrigated ***,no notable change was found in terms of heavy rainfall events and precipitation intensity

关键词： Nonhydrostatic regional climate model Irrigation effect Extreme events North China

SDCC: software-defined collective communication for distributed training

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Science China(Information Sciences) 2024年第9期67卷 105-125页

作者： Xin JIN zhen ZHANG Yunshan jia.Yun MA Xuanzhe LIU School of Computer Science Peking University Department of Computer Science and Technology Johns Hopkins University

Communication is crucial to the performance of distributed training. Today's solutions tightly couple the control and data planes and lack flexibility, generality, and performance. In this study, we present SDCC, a software-defined collective communication framework for distributed training. SDCC is based on the principle of modern systems design to effectively decouple the control plane from the data *** abstracts the operations for collective communication in distributed training with dataflow operations and unifies computing and communication with a single dataflow graph. The abstraction, together with the unification, is powerful: it enables users to easily express new and existing collective communication algorithms and optimizations, simplifies the integration with different computing engines(e.g., Py Torch and Tensor Flow) and network transports(e.g., Linux TCP and kernel bypass), and allows the system to improve performance by exploiting parallelism exposed by the dataflow graph. We further demonstrate the benefits of SDCC in four use cases.

关键词： machine learning systems distributed training deep learning collective communication software-defined networking

The Role of Consumer Privacy Concerns in Shaping Platform Strategy for Online Markets

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Journal of the Operations Research Society of China 2024年第2期12卷 363-386页

作者： Jin-Kun Yang Yong-Rui Duan jia.zhen Huo School Economics and Management Tongji UniversityShanghai 200092China

We investigate the effects of consumer privacy concerns on the pricing and personal data collection strategy of an online *** online platform derives revenues from disclosing consumer information to *** compete for the information in order to enable them to price discriminate and thus derive revenues from consumer purchases.A novel aspect of our research is that we allow the online platform to sell only a subset of consumer *** develop analytical models where consumers can/cannot protect their *** analysis yields three main ***,in the monopoly case,we find that when the consumer privacy disclosure aversion cost is relatively low,it is optimal for the platform to sell all consumer information to the ***,in the duopoly case,we illustrate that when the consumer privacy disclosure aversion cost is relatively low,the platform will sell all consumer information to only one firm;when the cost is moderate,the platform will choose to sell the information of only some consumers and to only one firm;when the cost is relatively high,the platform will select only some of the consumers and sell their information to both ***,it will be better for the platform to provide the information protection service for free when the privacy cost is low.

关键词： Price discrimination User privacy Consumer information Two-sided market Privacy disclosure aversion cost

Prevalence of Cannabis Use around the World:A Systematic Review and Meta-Analysis,2000-2024

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China CDC weekly 2024年第25期6卷 597-604,I0013,I0014页

作者： Qianning Wang zhen Qin Xing Xing He Zhu Zhongwei jia National Institute of Health Data Science Center for Drug Abuse Prevention and ControlPeking UniversityBeijingChina School of Public Health Peking UniversityBeijingChina

This study aims to perform a systematic review and meta-analysis on the global prevalence of cannabis use to inform drug prevention strategies,policy-making,and resource *** study initially screened 177,843 studies published between January 1,2000,and January 15,2024,using peer-reviewed databases including Web of Science,PubMed,Scopus,Embase,and Cochrane ***,595 studies were identified for data extraction,and 39 of these were selected as country-representative *** among the selected studies was assessed using the chi-squared test and I2 statistic,while sensitivity analysis was conducted to evaluate the robustness of the *** prevalence of cannabis use varied between 0.42%and 43.90%across 33 European countries,1.40%to 38.12%across 15 North and South American countries,0.30%to 19.10%across 16 Asian countries,and 1.30%to 48.70%across 18 Oceania and African *** pooled prevalence of cannabis use was 12.0%[95%confidence interval(CI):10.0,14.3]in countries where cannabis is legalized,compared to 5.4%(95%CI:4.3,6.9)in non-legalized *** findings indicate that the prevalence of cannabis use has disproportionately increased in most countries with the implementation of medical or recreational cannabis legalization policies and relevant geographic *** efforts are needed to monitor newly cannabis-legalized countries and prevent initial use.

关键词： prevention legal initially

Si/TiO_(2) carbon fiber core encapsulated in hierarchical multiple MXene@Co-MoS_(2) shells for constructing a free-standing anode of lithium storage

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Rare Metals 2024年第9期43卷 4222-4233页

作者： Xian-ping Du Ying Huang jia.ming Wang zhen-he Feng Xu Sun MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Shanghai Institute of Space Power-Sources Shanghai 200245China Ningbo Institute of Northwestern Polytechnical University Ningbo 315103China

Silicon-based(Si-based) materials offer more possibilities for generating new portable electronic devices due to their high specific capacities. However, their inferior electrical conductivity and volume expansion during cycling seriously limit their development. The optimum solution is to select specific materials to establish an exceptionally conductive and volume buffer structure,which can assist Si materials in developing their excellent lithium storage properties. In this study, Si particles were confined in TiO_(2)carbon fibers(TiO_(2)CFs) via electrospinning, after which they were encapsulated with MXene and Co-MoS_(2)(CMS) nanosheets to fabricate hierarchical ST-2@MXene@CMS films. TiO_(2)CF, MXene and CMS were employed to establish a coherent conductive network with one-, two-and three-dimensional electronic pathways to permit the unimpeded flow of electrons inside the electrode material. TiO_(2)CF, MXene and CMS acted precisely as multilayered buffers to ameliorate the volume change of Si particles during cycling. In addition, the CMS nanosheets were involved in lithium storage, contributing to the final electrochemical performance. Ultimately, the ST-2@MXene@CMS films served as free-standing electrodes, avoiding the impact of inactive interfaces on the electrochemical performance and fulfilling the lightweight requirement for new energy storage devices.

关键词： Si particles MXene Co-MoS_(2)nanosheets Hierarchical structure Lithium-ion batteries

The Astrometric Performance of the China Space Station Telescope(CSST)Sky Survey in Extending the Gaia Celestial Reference Frame

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Research in Astronomy and Astrophysics 2024年第8期24卷 133-140页

作者： Jun Yao jia.Cheng Liu Niu Liu Zi Zhu zhen-Wei Wang School of Astronomy and Space Science Key Laboratory of Modern Astronomy and Astrophysics(Ministry of Education)Nanjing UniversityNanjing 210023China University of Chinese Academy of Sciences Nanjing 211135China

The multi-color imaging sky survey conducted by the China Space Station Telescope(CSST)holds significant promise for advancing the development of the celestial reference *** this study,we focus on assessing the astrometric performance of the CSST celestial reference frame(CSST-CRF)in extending the Gaia Celestial Reference Frame 3(Gaia-CRF3).First,the orientation precision of the CSST reference frame is evaluated using a simulated set of extragalactic sources with CSST g magnitudes ranging from 18 to 25 *** estimated orientation uncertainty caused by random error insignificantly affects the alignment between Gaia-CRF3 and the ***,the systematic effect of incomplete CSST sky coverage on the alignment between CSST-CRF and Gaia-CRF3 is discussed by analyzing the differences between the subset of Gaia-CRF3 in the CSST observation region(Gaia-CRF3′)and Gaia-CRF3 as a *** the third International Celestial Reference Frame(ICRF3)S/X band as an intermediate reference frame,the orientation offset between Gaia-CRF3′and GaiaCRF3 is estimated to be 20μ*** offset is marginally larger than the orientation offset between Gaia-CRF3 and the ICRF3,approximately 15μ*** residual spin and glide rate of Gaia-CRF3′are derived from the proper motions,consistent with that of Gaia-CRF3 within the formal ***,we explore the role of CSST in establishing a multi-band celestial reference frame by comparing its limiting magnitude and observation accuracy with existing catalogs in the infrared and ultraviolet *** to its broad wavelength coverage and highprecision measurements,CSST is well-positioned to make significant contributions to the development of a multiband celestial reference frame.

关键词： astrometry-reference systems-surveys

Slow magnetic relaxation and photoluminescence behaviors of dilanthanide complexes bearing N_(8)O_(2)donor macrocyclic ligand

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Journal of Rare Earths 2024年第7期42卷 1298-1303,I0004页

作者： Pei-Yu Liao Yu-Quan Qi zhen Li jia.-Hua jia.Ming-Liang Tong Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education School of ChemistrySun Yat-Sen UniversityGuangzhou510006China

On account of the complicated magnetic exchange interactions between lanthanide ions,binuclear lanthanide complexes have broad application prospect in the field of single-molecule ***,it is necessary to develop reasonable bridging ligands to manipulate the directional assembly of binuclear lanthanide ***,we selected the macrocyclic ligand L^(N_(8)O_(2))to build up two new dilanthanide complexes[Ln_(2)(LN_(8)O_(2))(OpyO)_(2)(H_(2)O)2](NO_(3))_(2)(1-Ln,Ln=Dy,Tb;LN_(8)O_(2)=hexamethyl-tetraaza-dioxe-dipyrazolacycloicosaphane-2,9,12,19-tetraene;OpyOH=2-pyridinol-1-oxide).Dynamic magnetic studies show that 1-Dy exhibits slow relaxation behavior under a 1 kOe applied *** fitting analysis of relaxation times gives the effective energy barrier of 38.2 cm^(−1),and reveals that the slow magnetic relaxation behavior is dominated by the Orbach and Raman ***-resolution luminescence emission spectrum indicates the energy gap of 36.8 cm^(−1)between the ground state and the first excited state,consistent with the magnetic measurement results.1-Tb exhibits brilliant characteristic green light emission under UV light *** absolute quantum yield of 1-Tb is 44.8%,and its first-order fitted decay lifetime is 779.21μs at room *** study provides the way for directional construction of high-performance molecular materials with magnetic and optical dual-function.

关键词： Dilanthanide complexes Single-molecule magnets Macrocyclic ligand Photoluminescence behavior Rare earths

Optical edge-to-screw singularity state conversions

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Photonics Research 2024年第8期12卷 1689-1695页

作者： HAOLIN LIN JUNHUI jia.GUOHUA LIU YANWEN HU zhen LI zhenQIANG CHEN SHENHE FU Department of Optoelectronic Engineering Jinan UniversityGuangzhou 510632China Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Guangzhou 510632China Guangdong Provincial Engineering Research Center of Crystal and Laser Technology Guangzhou 510632China

Optical singularity states,which significantly affect propagation properties of light in free space or optical medium,can be geometrically classified into screw and edge *** different types of singularity states do not exhibit direct connection,being decoupled from each other in the absence of external *** we demonstrate a novel optical process in which a higher-order edge singularity state initially nested in the propagating Gaussian light field gradually involves into a screw singularity with a new-born topological charge determined by order of the edge *** considered edge state comprises an equal superposition of oppositely charged vortex and antivortex *** theoretically and experimentally realize this edge-to-screw conversion process by introducing intrinsic vortex–antivortex *** also present a geometrical representation for mapping this dynamical process,based on the higher-order orbital Poincaré*** this framework,the edge-to-screw conversion is explained by a mapping of state evolution from the equator to the north or south pole of the Poincaré*** demonstration provides a novel approach for manipulating singularity state by the intrinsic vortex–antivortex *** presented phenomenon can be also generalized to other wave systems such as matter wave,water wave,and acoustic wave.

关键词： interaction Poincaré wave

Dynamic Response of A Group of Cylindrical Storage Tanks with Baffles Considering the Effect of Soil Foundation

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China Ocean Engineering 2024年第1期38卷 129-143页

作者： SUN Ying WANG jia.dong HUO Rui-li ZHOU Ding GU zhen-yuan QIAN Wang-ping School of Transportation and Civil Engineering Nantong UniversityNantong 226019China Faculty of Civil Engineering and Mechanics Jiangsu UniversityZhenjiang 212013China College of Civil Engineering Nanjing Tech UniversityNanjing 211816China

The sloshing in a group of rigid cylindrical tanks with baffles and on soil foundation under horizontal excitation is studied *** solutions for the velocity potential are derived out by the liquid subdomain *** models with mass-spring oscillators are established to replace continuous *** with the least square technique,Chebyshev polynomials are employed to fit horizontal,rocking and horizontal-rocking coupling impedances of soil,respectively.A lumped parameter model for impedance is presented to describe the effects of soil on tank structures.A mechanical model for the soil-foundation-tank-liquid-baffle system with small amount of calculation and high accuracy is proposed using the substructure *** analytical solutions are in comparison with data from reported literature and numerical codes to validate the effectiveness and correctness of the *** dynamic properties and seismic responses of the soil-tank system are given for the baffle number,size and location as well as soil parameter.

关键词： cylindrical tanks multiple annular baffles equivalent analytical model soil−structure interaction subdomain method dynamic response