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Impacts of heterogeneous CO_(2)on water and carbon fluxes across the global land surface

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International Journal of Digital Earth 2021年第9期14卷 1175-1193页

作者： Jing Tian yongqiang zhang Xuanze zhang Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographical Sciences and Natural Resources Research(IGSNRR)Chinese Academy of Sciences(CAS)BeijingPeople’s Republic of China

Over the recent decades,the increase of atmospheric carbon dioxide(CO_(2))concentration has caused large effects on the earth ***,few studies have paid attention to the effects of heterogeneity of CO_(2)on the biosphere and the *** a coupled diagnostic biophysical model(PML-V2)and comparing three heterogeneous CO_(2)datasets(GOSAT,CMIP6 and CarbonTracker)against a baseline homogeneous data(ESRL),this study investigated the effects of heterogeneous CO_(2)on gross primary production(GPP),actual evapotranspiration(ET)and water use efficiency(WUE)across the *** results show that among the three heterogeneity CO_(2),CarbonTracker produced the highest CO_(2)concentration and showed the largest difference in ET(−6%to 2%),GPP(−2%to 5%)and WUE(4%to 11%)compared to those from the *** most effects of the CO_(2)heterogeneity occurred in *** was identified as a vulnerable region with prominent decrease in GPP and an increase in ET due to CO_(2)*** obvious increase in GPP and a decrease in ET appeared in the Amazon rainforest,the Congo rainforest,and eastern *** global scale,the effects of the CO_(2)heterogeneity on ET/GPP/WUE were not significant.

关键词： Global CO_(2)heterogeneity evapotranspiration gross primary production water use efficiency

Computing environmental life of electronic products based on failure physics

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Journal of Systems Engineering and Electronics 2016年第2期27卷 493-500页

作者： yongqiang zhang Zongchang Xu Chunyang Hu Academy of Armored Force Engineering Beijing 100072China Naval Air Force Institute Liaoning 125000China

In some situations, the accelerated life test on environmental stress for electronic products is not easily implemented due to various restrictions, and thus engineers are lacking of data of the product life test. Concerning this problem, environmental life of the printed circuit board（PCB） board is calculated by way of physics of failure. Influences of thermal cycle and vibration on PCB and its components are studied. Based on the analysis of force and stress between components and the PCB board in thermal cycle events and vibration events, four life computing models of pins and soldered dots are established. The miller damage ratio is used to calculate the accumulated damage of a pin or a soldered dot, and then the environment life of the PCB board can be determined by the first failed one. Finally, an example is used to illustrate the models and their calculations.

关键词： environmental life pins soldered dots printed cir-cuit board(PCB)

Synthesis of Diverse Oxetane Amino Acids via Visible-Light-Induced Photocatalytic Decarboxylative Giese-Type Reaction

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Chinese Journal of Chemistry 2024年第12期42卷 1341-1346页

作者： Haoliang Shi Yi Wan yongqiang zhang Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism Shanghai Key Laboratory of New Drug Designand School of PharmacyEast China University of Science and TechnologyShanghai200237 China

The divergent synthesis of versatile 3,3′-disubstituted oxetane amino acids by utilizing visible-light-induced photocatalytic decarboxylative Giese-type reaction has been demonstrated.3-Methyleneoxetane-derived substrates are readily available in a single-step and highly reactive as radical acceptors,allowing the production of versatile oxetaneγ-andα-amino acids in high yields.A distinct ring strain release-driven radical addition mechanism was preliminarily *** preparative power was further highlighted by the application in the synthesis of oxetane-containing dipeptides and azetidine amino acids,as well as the transformation of the product into novel oxetane-containing spiro-heterocycle pharmacophore.

关键词： Photoredox catalysis Decarboxylative Giese-type reaction Oxetane amino acids Amino acids Synthesis Radical reactions

Separating impacts of vegetation change and climate variability on streamflow using hydrological models together with vegetation data

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Science China(Technological Sciences) 2012年第7期55卷 1964-1972页

作者： LI HuiYun zhang yongqiang WANG BenDe Nanjing Institute of Geography ＆ Limnology Chinese Academy of Sciences Nanjing 210008 China CSIRO Land and Water GPO BOX 1666 CanberraACT 2601 Australia Faculty of Infrastructure Engineering Dalian University of Technology Dalian 116024 China

Vegetation information is seldom considered in lumped conceptual rainfall-runoff *** paper uses two modified rainfall-runoff models,the Xinanjiang-ET and SIMHYD-ET models in which vegetation leaf area index is incorporated,to investigate impacts of vegetation change and climate variability on streamflow in a Southern Australian catchment,the Crawford River experimental catchment,where Tasmanian blue gum plantations were introduced gradually from 1998 till *** Xinanjiang-ET and SIMHYD-ET models incorporate remotely-sensed leaf area index(LAI) data obtained from the Advanced Very High Resolution Radiometer(AVHRR) on board NOAA polar orbiting *** to the original versions,the Xinanjiang-ET and SIMHYD-ET models show marginal improvements in runoff simulations in the pre-plantation period(1882-1997).The calibrated Xinanjaing-ET and SIMHYD-ET models are then used to simulate plantation impact on streamflow in the post-plantation *** total change in streamflow between the pre-plantation and post-plantation periods is 32.4 mm/*** modelling results from the two models show that plantation reduces streamflow by 20.5 mm/a,and climate variability reduces streamflow by 11.9 mm/*** results suggest that increase in plantations can reduce streamflow substantially,even more than climate variability.

关键词： vegetation change climate variability streamflow leaf area index hydrological model Crawford River

Climate change detection and attribution in the Ganga-Brahmaputra-Meghna river basins

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Geoscience Frontiers 2021年第5期12卷 192-201页

作者： Chetan Sharma Anoop Kumar Shukla yongqiang zhang Civil Engineering Department JIETJodhpurRajasthanIndia Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China

Ganga-Brahmaputra-Meghna(GBM)river basin is the third-largest and one of the most populated river basins in the *** climate change is affecting most of the hydrometeorological variables across the globe,this study investigated the existence of climate change signal in all four climatological seasons in the GBM river basin and assessed the contribution of anthropogenic activities,i.e.,Greenhouse Gases(GHGs)emission in the *** decreasing trends in the monsoon and a small increase in pre-monsoon precipitation were *** change was detected in post-monsoon and winter season ***5 GCMs were used for climate change detection,change point estimation,and attribution *** Vector Machine(SVM)regression method was adopted to downscale GCM variables at the local ***-Carlo simulation approach was used to detect changes in different *** climate change‘signals’were detectable after the year 1980 using Signal to Noise ratio(SNR)method in the majority of central and north-western *** change point was detectable only in annual monsoon precipitation at the basin *** analysis indicated>50%contribution of anthropogenic activities(GHGs)to annual monsoon precipitation ***,there is high confidence that monsoon precipitation in GBM has significantly changed due to anthropogenic *** mitigation and adaption measures are also suggested,which may be adopted to manage the growing demand and water availability in the basin.

关键词： Ganga-Brahmaputra-Meghna(GBM) Climate change Support vector machine Signal to noise ratio Anthropogenic activities

Multi-band design for one-dimensional phononic crystals

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Science China(Physics,Mechanics & Astronomy) 2013年第7期56卷 1253-1262页

作者： zhang Pei WANG ZhenYu zhang yongqiang LIANG Xu College of Civil Engineering and Architecture Zhejiang University

Periodic composites with band gaps that prevent the propagation of elastic waves in certain frequency ranges can be used to control waves for a variety of engineering applications. Although studies on the characteristics of these materials, which are called phononic crystals (PCs), have yielded a large number of positive results in recent years, there is still a lack of effective design methods. In this work, a multi-objective optimization approach based on the band gap mechanism and an intelligent algorithm is used to design a one-dimensional (1D) slab construction of PCs. The design aims to fit pre-determined bands by arranging the available materials properly. Obtained by analyzing the wave transmission in periodic layers, the objective functions are linked to the optimization program to obtain a proper solution set. The results of the numerical simulations demonstrate that without constructing complicated structures, the design method is able to produce PCs that overcome the limitations of two-component PCs and hence can feasibly and effectively achieve the design targets. The design approach presented in this paper can be extended to two-or three-dimensional systems and has great potential for the development of sound/ultrasound isolation structures, multiple band frequency filters, and other applications.

关键词： phononic crystals multi-band design multi-objective optimization

Improving strength-ductility synchronously of Electron beam welded Ti600/Ti2AlNb joint through isothermal forging

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Progress in Natural Science:Materials International 2024年第3期34卷 532-539页

作者： yongqiang zhang Xiangyi Xue Guoming Zheng Jingli zhang Huiming Li Shewei Xin State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi'an Qin Ti Intelligent Manufacturing Technologies Co.Ltd. Northwest Institute for Nonferrous Metal Research Xi'an University of Science and Technology Avic Xi'an Aircraft Industry Group Company Ltd.

Different alloys can be flexibly combined to meet the performance needs of different parts of the compressor disc by welding process. However, achieving a good combination of dissimilar alloys with different mechanical properties has always been a research difficulty. In this work, a Ti600/Ti2AlNb joint was fabricated through electron beam welding and an isothermal forging was used to optimized its microstructure and mechanical performance. The isothermal forging process increases the ultimate tensile strength（UST） and yield strength（YS）of the Ti600/Ti2AlNb joint by ～18 %, while ～2.5 times the ductility. It is indicated that before forging, the Ti600/Ti2AlNb joint exhibits a much lower strength than that of Ti600 matrix, whereas the opposite is true after isothermal forging. The isothermal forging broken the coarse columnar grains of Ti600/Ti2AlNb joint and render to an equiaxed B2 structure in which the acicular α2and O phase are precipitated, resulting a synchronous enhancement of strength and ductility. This work may pave an effective routine for improving the comprehensive mechanical properties of dissimilar metal welding joint.

关键词： Electron beam welding Ti600/Ti2AlNb joint Isothermal forging Mechanical performance

Stiffness and Shear Stress Distribution of Glulam Beams in Elastic-Plastic Stage:Theory,Experiments and Numerical Modelling

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Journal of Renewable Materials 2023年第2期11卷 791-809页

作者： Lisheng Luo Xinran Xie yongqiang zhang Xiaofeng zhang Xinyue Cui Department of Civil Engineering College of Civil Engineering and ArchitectureHainan UniversityHaikouChina Department of Wooden Structure Construction College of Materials Science and EngineeringNanjing Forestry UniversityNanjingChina

Traditional methods focus on the ultimate bending moment of glulam beams and the fracture failure of materials with defects,which usually depends on empirical *** is no systematic theoretical method to predict the stiffness and shear distribution of glulam beams in elastic-plastic stage,and consequently,the failure of such glulam beams cannot be predicted *** address these issues,an analytical method considering material nonlinearity was proposed for glulam beams,and the calculating equations of deflection and shear stress distribution for different failure modes were *** proposed method was verified by experiments and numerical models under the corresponding *** showed that the theoretical calculations were in good agreement with experimental and numerical results,indicating that the equations proposed in this paper were reliable and accurate for such glulam beams with wood material in the elastic-plastic stage ignoring the influence of mechanic properties in radial and tangential directions of ***,the experimental results reported by the previous studies indicated that the method was applicable and could be used as a theoretical reference for predicting the failure of glulam beams.

关键词： Glulam beams load-deflection relationship shear stress distribution elastic-plastic stage numerical model

Characterizing the dynamics of soil organic carbon in grasslands on the Qinghai-Tibetan Plateau

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Science China Earth Sciences 2007年第1期50卷 113-120页

作者： zhang yongqiang TANG YanHong JIANG Jie YANG YongHui Environmental Biology Division National Institute for Environmental Studies305-8506 TsukubaJapan Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences100101 BeijingChina Research Center for Agricultural Resources Institute of Genetics and Develepmental Biology Chinese Academy of SciencesShijiazhuang 050021China

Carbon dynamics of grasslands on the Qinghai-Tibetan Plateau may play an important role in regional and global carbon cycles. The CENTURY model (Version 4.5) is used to examine temporal and spatial variations of soil organic carbon (SOC) in grasslands on the Plateau for the period from 1960 to 2002. The model successfully simulates the dynamics of aboveground carbon and soil surface SOC at the soil depth of 0-20 cm and the simulated results agree well to the measurements. Examination of SOC for eight typical grasslands shows different patterns of temporal variation in different ecosystems in 1960-2002. The extent of temporal variation increases with the increase of SOC of ecosystem. SOC increases first and decreases quickly then during the period from 1990 to 2000. Spatially, SOC density obtained for the equilibrium condition declines gradually from the southeast to the northwest on the plateau and showed a high heterogeneity in the eastern plateau. The results suggest that (i) SOC den-sity in the alpine grasslands shows remarkable response to climate change during the 42 years, and (ii) the net carbon exchange rate between the alpine grassland ecosystems and the atmosphere increases from 1990 to 2000 as compared with that before 1990.

关键词： carbon cycle CENTURY model climate change global warming soil organic carbon.