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Climate change and glacier area variations in China during the past half century

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Journal of Mountain Science 2016年第8期13卷 1345-1357页

作者： tian Hong-zhen YANG tai-bao LV Hui LI Cheng-xiu he Ying-bin School of Management Tianjin Polytechnic University Institute of Glaciology and Ecogeography College of Earth and Environmental Sciences Lanzhou University Remote Sensing Laboratories Department of Geography University of Zurich Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences

Glacier variations in the Tibetan Plateau and surrounding mountain ranges in China affect the livelihood of over one billion people who depend on water from the Yellow, Yangtze, Brahmaputra, Ganges and Indus rivers originating in these areas. Based on the results of the present study and published literature, we found that the glaciers shrank ：5.7% in area from 1963 to 20：0 with an annual area change of -0.33%. The shrinkage generally decreased from peripheral mountain ranges to the interior of Tibet. The linear trends of annual air temperature and precipitation at 147 stations were 0.36℃（10a）^-1 and 8.96 mm （10a）^-1 respectively from 1961 to 2010. The shrinkage of glaciers was well correlated with the rising temperature and the spatial patterns of the shrinkage were influenced by other factors superimposed on the rising temperature such as glacier size, type, elevation, debris cover and precipitation.

关键词： Glacier area Climate change Air

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

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Acta Metallurgica Sinica(English Letters) 2015年第7期28卷 809-816页

作者： Chao Yang he-Fei Huang Massey de los Reyes Long Yan Xing-tai Zhou tian Xia De-Liang Zhang Shanghai Institute of Applied Physics Chinese Academy of Science (CAS) Institute of Materials Engineering Australian Nuclear Science and Technology Organisation State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University

Silicon carbide nanoparticle-reinforced nickel-based composites（Ni–Si CNP）,with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma *** addition,unreinforced pure nickel samples were also prepared for comparative *** characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy（TEM） was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile *** results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was *** homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain *** the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si ***,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling *** all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening（Orowan effects） and particle strengthening（Hall–Petch effects）.For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased *** to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.

关键词： Ni-SiCNP composite Mechanical alloying Spark plasma sintering Transmission electron microscopy Tensile test

The Dynamical Casimir Effect versus Collective Excitations in Atom Ensemble

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Chinese Physics Letters 2011年第6期28卷 118-121页

作者： ZHANG Xue ZheNG tai-Yu tian tian PAN Shu-Mei Institute of Theoretical Physics Northeast Normal UniversityChangchun 130024

The Dynamical Casimir effect and collective excitations in atom ensemble are investigated in a non-stationary *** results show that the dynamical Casimir effect leads to the collective excitations of atom ensemble due to absorption of the created *** remarkable feature indicates that the atom ensemble can serve as a detector for the process of photon production in a non-stationary *** by measuring the collective excitations of the atom ensemble,the dynamical Casimir effect can indirectly be verified.

关键词： collective ensemble excitation

Machine learning method to predict dynamic compressive response of concrete-like material at high strain rates

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Defence Technology（防务技术） 2023年第5期23卷 100-111页

作者： Xu Long Ming-hui Mao tian-xiong Su Yu-tai Su Meng-ke tian School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'anChina School of Civil Engineering Liaoning Petrochemical UniversityFushunChina Beijing Microelectronics Technology Institute BeijingChina

Machine learning(ML)methods with good applicability to complex and highly nonlinear sequences have been attracting much attention in recent years for predictions of complicated mechanical properties of various *** one of the widely known ML methods,back-propagation(BP)neural networks with and without optimization by genetic algorithm(GA)are also established for comparisons of time cost and prediction *** the aim to further increase the prediction accuracy and efficiency,this paper proposes a long short-term memory(LSTM)networks model to predict the dynamic compressive performance of concrete-like materials at high strain *** explicit analysis is performed in the finite element(FE)software ABAQUS to simulate various waveforms in the split Hopkinson pressure bar(SHPB)experiments by applying different stress waves in the incident *** FE simulation accuracy is validated against SHPB experimental results from the viewpoint of dynamic increase *** order to cover more extensive loading scenarios,60 sets of FE simulations are conducted in this paper to generate three kinds of waveforms in the incident and transmission bars of SHPB *** training the proposed three networks,the nonlinear mapping relations can be reasonably established between incident,reflect,and transmission *** measures are used to quantify the network prediction accuracy,confirming that the predicted stress-strain curves of concrete-like materials at high strain rates by the proposed networks agree sufficiently with those by FE *** is found that compared with BP network,the GA-BP network can effectively stabilize the network structure,indicating that the GA optimization improves the prediction accuracy of the SHPB dynamic responses by performing the crossover and mutation operations of weights and thresholds in the original BP *** eliminating the long-time dependencies,the proposed LSTM network achieves better results than the BP

关键词： Deep learning LSTM network GA-BP network Dynamic behaviour Concrete-like materials

Numerical Simulation on the Resistance Performance of Ice-Going Container Ship Under Brash Ice Conditions

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China Ocean Engineering 2018年第5期32卷 546-556页

作者： GUO Chun-yu ZHANG Zuo-tian tian tai-ping LI Xia-yan ZHAO Da-gang College of Shipbuilding Engineering Harbin Engineering University SUMEC Marine Co. Ltd.

Ice resistance prediction is a critical issue in the preliminary design of ships navigating brash ice conditions, which is closely related to the safety of a ship to navigate encounter brash ice, and has significant effects on the kinds of propellers and motor power needed. In research on this topic, model tests and full-scale tests on ships have thus far been the primary approaches. In recent years, the application of the finite element method(FEM) has also attracted interest. Some researchers have conducted numerical simulations on ship–ice interactions using the fluid–structure interaction(FSI) method. This study used this method to predict and analyze the resistance of an ice-going ship, and compared the results with those of model ship tests conducted in a towing tank with synthetic ice to discuss the feasibility of the FEM. A numerical simulation and experimental methods were used to predict the brash ice resistance of an ice-going container ship model in a condition with three concentrations of brash ice(60%, 80%, and 90%). A comparison of the results yielded satisfactory agreement between the numerical simulation and the experiments in terms of both observed phenomena and resistance values, indicating that the proposed numerical simulation has significant potential for use in related studies in the future.

关键词： brash ice resistance fluid–structure interaction(FSI) finite element method(FEM) numerical simulation model ship test

A New Way to CCK Performance Analysis under AWGN Channel

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China Communications 2007年第4期4卷 72-78页

作者： tai Nengjian Wu Jie Gou Yanxin tian Yan AF Engn Univ Telecommun Engn Inst Xian 710077 Shaanxi Peoples R China

In this paper,M-ary Quaternary Orthogonal Keying modulation(MQOK) is proposed based on the analysis of Complementary Code Keying(CCK) and Mary Bi-orthogonal Keying(MBOK).Besides,CCK can be defined as a kind of *** analyzing the performance of MQOK on the condition of additive white Gaussian noise(AWGN) channel,new closed-form formulae for CCK modulation are gained. Comparison between the numerical result and the simulation result confirms that these formulae are more accurate and practical to manipulate.

关键词： CCK MQOK AWGN channel Performance analysis

De-biased knowledge distillation framework based on knowledge infusion and label de-biasing techniques

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Journal of Electronic Science and Technology 2024年第3期22卷 57-68页

作者： Yan Li tai-Kang tian Meng-Yu Zhuang Yu-Ting Sun School of Economics and Management University of Electronic Science and Technology of ChinaChengdu611731China School of Economics and Management Beijing University of Posts and TelecommunicationBeijing100876China School of Electrical Engineering and Computer Science The University of QueenslandBrisbane4072Australia

Knowledge distillation,as a pivotal technique in the field of model compression,has been widely applied across various ***,the problem of student model performance being limited due to inherent biases in the teacher model during the distillation process still *** address the inherent biases in knowledge distillation,we propose a de-biased knowledge distillation framework tailored for binary classification *** the pre-trained teacher model,biases in the soft labels are mitigated through knowledge infusion and label de-biasing *** on this,a de-biased distillation loss is introduced,allowing the de-biased labels to replace the soft labels as the fitting target for the student *** approach enables the student model to learn from the corrected model information,achieving high-performance deployment on lightweight student *** conducted on multiple real-world datasets demonstrate that deep learning models compressed under the de-biased knowledge distillation framework significantly outperform traditional response-based and feature-based knowledge distillation models across various evaluation metrics,highlighting the effectiveness and superiority of the de-biased knowledge distillation framework in model compression.

关键词： De-biasing Deep learning Knowledge distillation Model compression

A mite parasitoid,Pyemotes zhonghuajia,negatively impacts the fitness traits and immune response of the fall armyworm,Spodoptera frugiperda

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Journal of Integrative Agriculture 2024年第1期23卷 205-216页

作者： Yanfei Song tai’an tian Yichai Chen Keshi Zhang Maofa Yang Jianfeng Liu Institute of Entomology Guizhou Provincial Key Laboratory for Agricultural Pest Management of the Mountainous RegionGuizhou University/Scientific Observing and Experiment Station of Crop Pests in GuiyangMinistry of Agriculture and Rural AffairsGuiyang 550025China Administration of Guizhou Fanjingshan National Nature Reserve Jiangkou 554400China Centre for Biodiversity and Biosecurity School of Biological SciencesThe University of AucklandAuckland 1072New Zealand College of Tobacco Science Guizhou UniversityGuiyang 550025China

Parasitoids are key regulators in ecological communities and widely used as agents in biocontrol *** fall armyworm,Spodoptera frugiperda,recently invaded multiple continents and caused substantial economic losses in *** zhonghuajia,a newly identified mite parasitoid,has shown potential for controlling various agricultural insect ***,this study tested the performance of *** in parasitising *** also investigated the sublethal effects of parasitism by *** on host fitness traits,transgenerational impacts,and cellular and humoral *** result showed that the fifth-instar larvae of *** parasitised by 40 *** were all dead(i.e.,a lethal effect),while parasitism by 5 or 10 *** was considered sublethal since many *** survived to adulthood and produced offspring after *** sublethal influences from parasitism by *** resulted in reduced pupal weight,adult emergence rate and fecundity,but increased developmental time and *** at both lethal(40 mites)and sublethal(10 mites)levels impaired the cellular and humoral immunity of *** study presents the first empirical evidence that mite parasitoids can negatively influence host ***,it provides insights into the biocontrol potential of mite parasitoids and their interactions with hosts.

关键词： Pyemotes zhonghuajia Spodoptera frugiperda immunity parasitically-induced influence biocontrol parasitoid

Search for the Metal-weak Thick Disk from the LAMOST DR5

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Research in Astronomy and Astrophysics 2022年第2期22卷 72-85页

作者： tai-Sheng Yan Jian-Rong Shi Hao tian Wei Zhang Bo Zhang Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100012China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Space Astronomy and Technology National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Department of Astronomy Beijing Normal UniversityBeijing 100875China

Based on the data release of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope survey(LAMOST DR5)and the Gaia Early Data Release 3(Gaia EDR3),we construct a sample containing 46,109 giant(log g≤3.5 dex)stars with heliocentric distance d≤4 kpc,and the sample is further divided into two groups of the inner(RGC8.34 kpc).The LZdistributions of our program stars in the panels with different[Fe/H]and[α/Fe]suggest that the thick-disk consists of two distinct components with different chemical compositions and kinematic *** the inner region,the metal-weak thick disk(MWTD)significantly contributes when[α/Fe]>+0.2 dex and[Fe/H]he canonical thick-disk(TD)dominates when[Fe/H]>-0.8 ***,MWTD clearly appears only when[α/Fe]>+0.2 dex and[Fe/H]he outer region,and its proportion is lower than that of the inner region within the same *** results can be obtained from the V_(φ)*** higher fraction of MWTD in the inner region than that in the outer region implies that MWTD may form in the inner disk,and is observational evidence about the inside-out disk formation scenario.

关键词： stars:abundances stars:atmospheres Galaxy:structure Galaxy:kinematics and dynamics methods:data analysis