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ANALYSIS OF 2-D THIN STRUCTURES BY THE MESHLESS REGULAR HYBRID BOUNDARY NODE METHOD

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Acta Mechanica Solida Sinica 2002年第1期15卷 36-44页

作者： zhang jianming Yao Zhenhan Tsing Hua Univ Dept Mech Engn Beijing 100084 Peoples R China

Thin structures are generally solved by the Finite Element Method(FEM), using plate or shell finite elements which have manylimitations in applications, such as numerical locking, edge effects,length scaling and the cnvergence problem. Recently, by proposing anew approach to tranting the nearly- singular integrals, Liu et *** a BEM to successfully solve thin structures with thethickness-to- length ratios in the micro-or nano-scales. On the otherhand, the meshless Regular Hybrid Boundary Node Method (RHBNM), whichis proposed by the current authors and based on a modified functionaland the Moving Least-Square (MLS) approximation, has very promisingapplications for engineering problems owing To its meshless natureand dimension-reduction advantage, and not involving any singular ornearly-singular Integrals. Test examples show that the RHBNM can alsobe applied readily to thin structures with high accu- Racy withoutany modification.

关键词： shell-like structures meshless moving least squares approximation hybridboundary node method

Mechanical behaviors of warm and ice-rich frozen soil stabilized with sulphoaluminate cement

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Journal of Mountain Science 2024年第1期21卷 335-345页

作者： WANG Honglei zhang Hu zhang jianming zhang Qi YIN Zhenhua State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China School of Civil Engineering and Transportation Northeast Forestry UniversityHarbin 150040China National Key Laboratory of Green and Long-Life Road Engineering in Extreme Environment CCCC First Highway Consultants Co.LtdXi'an 710065China Railway Engineering Research Institute China Academy of Railway Sciences Corporation LimitedBeijing 100081China

The warm and ice-rich frozen soil is characterized by high unfrozen water content, low shear strength and large compressibility, which is unreliable to meet the stability requirements of engineering infrastructures and foundations in permafrost regions. In this study, a novel approach for stabilizing the warm and ice-rich frozen soil with sulphoaluminate cement was proposed based on chemical stabilization. The mechanical behaviors of the stabilized soil, such as strength and stress-strain relationship, were investigated through a series of triaxial compression tests conducted at -1.0℃, and the mechanism of strength variations of the stabilized soil was also explained based on scanning electron microscope test. The investigations indicated that the strength of stabilized soil to resist failure has been improved, and the linear Mohr-Coulomb criteria can accurately reflect the shear strength of stabilized soil under various applied confining pressure. The increase in both curing age and cement mixing ratio were favorable to the growth of cohesion and internal friction angle. More importantly, the strength improvement mechanism of the stabilized soil is attributed to the formation of structural skeleton and the generation of cementitious hydration products within itself. Therefore, the investigations conducted in this study provide valuable references for chemical stabilization of warm and ice-rich frozen ground, thereby providing a basis for in-situ ground improvement for reinforcing warm and ice-rich permafrost foundations by soil-cement column installation.

关键词： Permafrost regions Frozen soil Mechanical behavior Chemical stabilization Ground improvement Ground modification

Experimental and numerical interpretation on composite foundation consisting of soil-cement column within warm and ice-rich frozen soil

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Journal of Mountain Science 2024年第1期21卷 313-321页

作者： WANG Honglei zhang jianming WEI Shoucai SUN Zhizhong zhang Hu School of Civil Engineering Hebei University of EngineeringHandan 056038China State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Second Geological Brigade Bureau of Geology and Mineral Resources Exploration and DevelopmentLhasa 850000China Da Xing’anling Observation and Research Station of Frozen Ground Engineering and Environment Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesJiagedaqi 165100China School of Civil Engineering Northeast Forestry UniversityHarbin 150040China

Affected by climate warming and anthropogenic disturbances, the thermo-mechanical stability of warm and ice-rich frozen ground along the Qinghai-Tibet engineering corridor(QTEC) is continuously decreased, which may delay the construction of major projects in the future. In this study, based on chemical stabilization of warm and icerich frozen ground, the soil-cement column(SCC) for ground improvement was recommended to reinforce the foundations in warm and ice-rich permafrost regions. To explore the validity of countermeasures mentioned above, both the original foundation and the composite foundation consisting of SCC with soil temperature of -1.0℃ were prepared in the laboratory, and then the plate loading tests were carried out. The laboratory investigations indicated that the bearing capacity of composite foundation consisting of SCC was higher than that of original foundation, and the total deformation of original foundation was greater than that of composite foundation, meaning that overall stability of foundation with warm and ice-rich frozen soil can be improved by SCC installation. Meanwhile, a numerical model considering the interface interaction between frozen soil and SCC was established for interpretating the bearing mechanism of composite foundation. The numerical investigations revealed that the SCC within composite foundation was responsible for the more applied load, and the applied load can be delivered to deeper zone in depth due to the SCC installation, which was favorable for improving the bearing characteristic of composite foundation. The investigations provide the valuable guideline for the choice of engineering supporting techniques to major projects within the QTEC.

关键词： Chemical stabilization Ground improvement Composite foundation Frozen soil engineering Qinghai-Tibet engineering corridor

Relations between oxygen stable isotopic ratios in precipitation and relevant meteorological factors in southwest China

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Science China Earth Sciences 2007年第4期50卷 571-581页

作者： zhang XinPing LIU JingMiao SUN WeiZheng HUANG YiMin zhang jianming College of Resources and Environment Hunan Normal UniversityChangsha 410081China Chinese Academy of Meteorological Sciences Beijing 100081China Cold and Arid Regions Environmental and Engineering Research Institute Lanzhou 730000China

The correlations of isotopic ratios in precipitation with temperature, air pressure and humidity at dif- ferent altitudes, in southwest China, are analyzed. There appear marked negative correlations for the δ 18O in precipitation with precipitation amount, vapor pressure and atmospheric precipitable water (PW) at Mengzi, Simao and Tengchong stations on synoptic timescale; the marked negative correlations between the δ 18O in precipitation and the diurnal mean temperature at 400 hPa, 500 hPa, 700 hPa and 850 hPa are different from the temperature effect in middle-high-latitude inland. Moreover, the notable positive correlation between the δ 18O in precipitation and the dew-point deficit △Td at different altitudes is found at the three stations. On annual timescale, the annual precipitation amount weighted mean δ 18O display the negative correlations not only with annual precipitation but also with annual mean temperature at 500 hPa. It can be deduced that, in the years with abnormally strong summer monsoon, more warm and wet air from low-latitude oceans is transported northward along the vapor channel located in southwest China and generates abnormally strong rainfall on the way. Meanwhile, the ab- normally strong condensation process will release more condensed latent heat into atmosphere, and lead to the rise of atmospheric temperature during rainfall, but decline of the δ 18O in precipitation. On the contrary, in the years with abnormally weak summer monsoon, the abnormally weak condensation process will release less condensed latent heat into atmosphere, and lead to the decline of atmos- pheric temperature during rainfall, but increase of the δ 18O in precipitation.

关键词： southwest China stable isotope precipitation temperature humidity correlation

2018: The Hottest Summer in China and Possible Causes

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Journal of Meteorological Research 2019年第4期33卷 577-592页

作者： Ting DING Yuan YUAN jianming zhang Hui GAO National Climate Center China Meteorological AdministrationBeijing 100081 Hunan Climate Center Changsha 410118

In 2018,China experienced the hottest summer since *** maximum,mean,and minimum temperatures all reached the *** temperatures in most regions were much higher than normal;in northern China especially,the temperature anomalies were above double of the standard *** variations of temperature anomalies appeared in the national mean and in northern China on different timescales from intraseasonal to annual,indicating that the above normal temperature in northern China contributed significantly to the record-breaking hot summer of entire *** among the high temperature in summer 2018,the tropospheric circulation,and the global sea surface temperatures(SSTs)are further *** is found that the intensified and more northward western Pacific subtropical high(WPSH),weakened Northeast China cold vortex(NECV),and positive geopotential height anomaly from northern China to the Sea of Japan resulted in the abnormally high temperature in summer *** late July to mid August,the WPSH was stronger than normal,with its ridge line jumping to north of 40°N;meanwhile,the NECV was much weaker and more northward than normal;both of the two systems led to the persistent high temperature in northern China during this *** addition,the SSTs in Kuroshio and its extension area(K–KE)in summer 2018 were also the highest since 1961 and the greatest positive SST anomaly in K–KE was favorable for the above normal geopotential height over North China–Northeast China–Japan at 500 hPa,giving rise to the exceptionally high temperature in northern China.

关键词： summer temperature western Pacific subtropical high(WPSH) Northeast China cold vortex(NECV) atmospheric circulation Kuroshio and its extension(K-KE)

Visual Object Tracking via Cascaded RPN Fusion and Coordinate Attention

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Computer Modeling in Engineering & Sciences 2022年第9期132卷 909-927页

作者： jianming zhang Kai Wang Yaoqi He Lidan Kuang School of Computer and Communication Engineering Changsha University of Science and TechnologyChangsha410114China Hunan Provincial Key Laboratory of Intelligent Processing of Big Data on Transportation Changsha University of Science and TechnologyChangsha410114China

Recently,Siamese-based trackers have achieved excellent performance in object ***,the high speed and deformation of objects in the movement process make tracking ***,we have incorporated cascaded region-proposal-network(RPN)fusion and coordinate attention into Siamese *** proposed network framework consists of three parts:a feature-extraction sub-network,coordinate attention block,and cascaded RPN *** exploit the coordinate attention block,which can embed location information into channel attention,to establish long-term spatial location dependence while maintaining channel ***,the features of different layers are enhanced by the coordinate attention *** then send these features separately into the cascaded RPN for classification and *** to the two classification and regression results,the final position of the target is *** verify the effectiveness of the proposed method,we conducted comprehensive experiments on the OTB100,VOT2016,UAV123,and GOT-10k *** with other state-of-the-art trackers,the proposed tracker achieved good performance and can run at real-time speed.

关键词： Object tracking deep learning coordinate attention cascaded RPN

Synthesis,characterization,and adsorption performance of Pb(Ⅱ)-imprinted polymer in nano-TiO_2 matrix

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Journal of Environmental Sciences 2009年第12期21卷 1722-1729页

作者： LI Chunxiang GAO Jie PAN jianming zhang Zulei YAN Yongsheng School of Chemistry and Chemical Engineering Jiangsu University Zhenjiang 212013 China

Surface ion-imprinted in combination with sol-gel process was applied to synthesis a new Pb（Ⅱ）-imprinted polymer for selective separation and enrichment of trace Pb（Ⅱ） from aqueous solution. The prepared material was characterized by using the infrared spectra, X-ray diffractometer, and scanning electron microscopy. The batch experiments were conducted to study the optimal adsorption condition of adsorption trace Pb（Ⅱ） from aqueous solutions on Pb（Ⅱ）-imprinted polymer. The equilibrium was achieved in approximately 4,0 h, and the experimental kinetic data were fitted the pseudo second-order model better. The maximum adsorption capacity was 22.7 mg/g, and the Langmuir equation fitted the adsorption isotherm data. The results of selectivity experiment showed that selectively adsorbed rate of Pb（Ⅱ） on Pb（Ⅱ）-imprinted polymer was higher than all other studied ions. Desorption conditions of the adsorbed Pb（Ⅱ） from the Pb（Ⅱ）-imprinted polymer were also studied in batch experiments. The prepared Pb（Ⅱ）-imprinted polymer was shown to be promising for the separation and enrichment of trace Pb（Ⅱ） from water samples. The adsorption and desorption mechanisms were proposed.

关键词： Pb(Ⅱ) ion-imprinted sol-gel adsorption selective

Electrostatics advancing green catalysis events

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Science China Chemistry 2023年第7期66卷 1881-1885页

作者： Xiaoxue Song Shun Li jianming zhang Weidong Shi Long zhang Institute of Quantum and Sustainable Technology(IQST) School of Chemistry and Chemical EngineeringJiangsu UniversityZhenjiang 212013China

Developing new and more-efficient catalytic ways to control chemical reactivity and selectivity has been a constant quest for chemists in the fields of chemical manufacturing and fundamental *** external electric fields(OEEFs)are emerging as the“smart effector”to manipulate a range of chemical changes(Figure 1)[1].Unlike the traditional approach of accelerating rates by adding specific chemical entities of molecular catalysts,electrostatic catalysis entails the key advantages of(1)removing the trial-anderror work of searching for a suitable catalyst.

关键词： catalyst. catalysis Figure

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金牡丹不同茶类夏秋茶香气品质差异分析

食品科学 2025年第2期46卷 171-182页

作者：唐梦婷廖献盛吴先寿魏明秀郑玉成金珊张见明叶乃兴福建农林大学园艺学院农作物遗传育种与综合利用教育部重点实验室福建福州350002 武夷学院中国乌龙茶产业协同创新中心福建武夷山354300 福建谦谦一叶茶业科技有限公司福建寿宁355500 寿宁县茶产业发展中心福建寿宁355500

以‘金牡丹’品种夏、秋季嫩梢为原料,分别加工成绿茶、黄茶、白茶、乌龙茶及红茶,采用顶空固相微萃取-气相色谱-质谱联用技术对夏、秋季的5类茶中的挥发性代谢物进行测定和分析。结果表明,夏茶中鉴定出522种挥发性代谢物,以萜类、酯类... 详细信息

以‘金牡丹’品种夏、秋季嫩梢为原料,分别加工成绿茶、黄茶、白茶、乌龙茶及红茶,采用顶空固相微萃取-气相色谱-质谱联用技术对夏、秋季的5类茶中的挥发性代谢物进行测定和分析。结果表明,夏茶中鉴定出522种挥发性代谢物,以萜类、酯类及醇类为主;秋茶中鉴定出502种挥发性代谢物,以萜类、酯类和杂环化合物为主。香气活性值分析表明,β-紫罗兰酮、α-紫罗兰酮、癸醛、苯甲酸甲酯、香叶醇等是金牡丹绿茶的关键呈香物质;β-紫罗兰酮、2-乙氧基-3-甲基吡嗪、癸醛、苯甲酸甲酯、香叶醇等是金牡丹黄茶的关键呈香物质;香叶醇、苯乙醛、水杨酸甲酯、(E)-芳樟醇氧化物、2-乙氧基-3-甲基吡嗪等是金牡丹白茶的关键呈香物质;吲哚、苯甲酸甲酯、苯乙醛、香叶醇、(E)-芳樟醇氧化物等是金牡丹乌龙茶的关键呈香物质;香叶醇、芳樟醇、苯乙醛、苯甲酸甲酯、水杨酸甲酯等是金牡丹红茶的关键呈香物质。秋茶中呈香物质的贡献、种类与数量均多于夏茶,其中,香叶醇、水杨酸甲酯、苯乙醇等42种关键呈香物质在秋季样品中香气活性值均高于夏季。整体而言,金牡丹茶以花香类为主要香型,秋茶香气品质显著优于夏茶,香叶醇、芳樟醇、2-乙氧基-3-甲基吡嗪、苯甲酸甲酯等14种挥发性代谢物为金牡丹茶品种的关键香气物质。

关键词：金牡丹不同茶类夏秋茶香气品质香气活性值