检索结果-南通市图书馆

Contamination by Organochlorine Pesticides in the Estuaries of Southeast China

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2002年第2期18卷 153-160页

作者： Z.L.Zhang H.S.Hong J.L.Zhou M.H.Dai K.Maskaouib w.q.chen Department of Environmental Science and Engineering Tsinghua POPs Research CentreTsinghua UniversityBeijing 100084China Key Laboratory of Marine Environmental Science of Ministry of Education Environmental Science Research CentreXiamen Universi-tyXiamen 361005China School of Chemistry Physics and Environmental ScienceUniversity of SussexFalmerBrighton BN19QJUK

Persistent organic pollutants(POPs) such as organochlorine pesticides are of global concern due to their widespread occurrence and persistence. This paper reports recent research studying the distribution and fate of organochlorine pesticides in the Jiulong River, the Minjiang River and the Pearl River estuaries in Southeast China. Eighteen organochlorine pesticides were extracted from water, pore water and sediment samples, followed by analysis by GC ECD. The results showed that the contamination levels were similar in these three estuaries. The levels of the total organochlorine pesticides in porewater were significantly higher than those in surface water, due to the high affinity of these hydrophobic compounds for sediment phase. Among the hexachlorocyclohexane(HCH) compounds, β HCH was found to be the most important isomer. The analysis of 1,1,1 trichloro 2,2 bis chlorophenyl ethane(DDT) and its metabolites showed that 1,1 dichloro 2[ o chlorophenyl] 2[ p chlorophenyl] ethylene(DDE) was dominant in the group.

关键词： Organochlorine insecticides DDT Lindane Jiulong River Estuary Minjiang River Estuary Pearl River Estuary water Sediment

STRUCTRUAL THEORIES OF MULTIFERROIC PLATES AND SHELLS

在线全文

学校读者我要写书评

暂无评论

STRUCTRUAL THEORIES OF MULTIFERROIC PLATES AND SHELLS

Topological phase transitions and Majorana zero modes induced by the periodic potential in an antiferromagnetic chain

第二届亚洲功能材料与结构力学大会

作者： C.L.Zhang~1 w.q.chen~2 1 Department of Civil Engineering Zhejiang University Zijingang Campus Hangzhou 310058 2 Department of Engineering Mechanics Zhejiang University Yuquan Campus Hangzhou 310027

＜正＞Analogical to that for elastic plates as proposed by ***,the linear structural theories of multiferroic plates and shells are derived using the series expansion *** an orthogonal curvilinear coordinate system,the field of displacements is expanded in an infinite series of powers of the thickness-coordinate of the *** local coordinate of the thickness is introduced in the expansion of the fields of electric and magnetic potentials,which is different from the expansion of *** the variational principle,we obtain two-dimensional governing equations and the associated boundary conditions of the *** setting the Lame coefficients corresponding to the coordinates at the middle surface of the shell to unit,and the two principal radii of the middle surface of the shell to infinity,the shell theory can directly be degenerated into the plate theory.

关键词： structural theory multiferroic materials plates shells series expansion

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2023年第8期75卷 156-162页

作者： K w Shen q chen College of Physics and Mechanical&Electrical Engineering Jishou UniversityJishou 416000China School of Computational Science and Electronics Hunan Institute of EngineeringXiangtan 411104China

we investigate the topological properties of an antiferromagnetic(AFM)chain with an on-site periodic potential,considering the intrinsic spin–orbit coupling and an external Zeeman field along with the *** results indicate that Majorana zero modes(MZMs)can be observed by adjusting the strength of the periodic *** have calculated the energy spectrum,the wave-function and transport properties,and all these results support the existence of MZMs in the AFM ***,multiple topological phase transitions occur as the strength of the periodic potential changes,and several regions support MZMs.

关键词： AFM chain Majorana zero modes topological phase transitions periodic potential

The Novel Mechanical Property of Tongue of a woodpecker

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2009年第3期6卷 214-218页

作者： P Zhou X q Kong C w wu Z chen National Key Laboratory for Structural Analysis of Industrial Equipment Dalian University of Technology Department of Civil and Environmental Engineering University of Missouri

Biomaterials such as bone,teeth,nacre and silk are known to have superior mechanical properties due to their specific nanocomposite *** we report that the woodpecker's tongue exhibits a novel strength and flexibility due to its special composite micro/*** tongue consists of a flexible cartilage-and-bone skeleton covered with a thin layer tissue of high strength and *** the interface between the cartilage-and-bone skeleton and the tissue layer,there is a hierarchical fiber-typed *** is this special design of the tongue that makes the woodpeckers efficient in catching the insects inside *** special micro/nanostructures of the woodpecker's tongue show us a potential method to enhance the interfacial connection between soft and hard material layers for bio-inspired composite system designs.

关键词： woodpeckcr hyoid cartllage multilevel structure tensile strength

Synthesis and Properties of Layered Oxides LiCo_(1-x)Ni_xO_2

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 1997年第5期13卷 405-408页

作者： Lin, q chen, N Ye, w Liu, RM Luo, JS GEN RES INST NONFERROUS MET BEIJING 100088PEOPLES R CHINA

The mechanism of LiCo1－xNixO2(x=0, 0.5, 1) synthesis from carbonates or hydrates was studied by thermogravimetric analysis and X-ray diffraction to identify the medium and final products. The synthesis process from carbonates can be divided into two steps. Below 300℃cobalt carbonate and/or nickel carbonate decompose forming oxides. Over 300℃ Li2CO3 decomposes and reacts with Co and/or Ni oxides gradually, as a result Co++ and/or Ni++ areoxidized to Co+++ and/or Ni+++, finally LiCo1-xNixO2 forms. The proportion of cobalt tonickel in the starting mixture and atmosphere during synthesis affects the structure of ***1-xNixO2(x≤0.5) can be synthesized in air or oxygen and characterized by solid solutionof LiCoO2 and LiNiO2. LiNiO2 can be obtained only from hydrates and in oxygen *** and LiCo0.5Ni0.5O2 have higher first charge capacity than that of LiCoO2. Their discharge capacity reaches a level with that of LiCoO2 and has reasonable reversibility.

关键词： Lithium batteries

Localized space-tim e method of fundamental solutions for three-dimensional transient diffusion problem

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2020年第5期36卷 1051-1057,I0002页

作者： L.qiu J.Lin q.-H.qin w.chen International Center for Simulation Software in Engineering and Sciences College of Mechanics and MaterialsHohai UniversityNanjing 210098China College of Engineering and Computer Science Australian National UniversityCanberraACT 2601Australia State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China State Key Laboratory of Acoustic Institute of AcousticsChinese Academy of SciencesBeijing 100190China

A localized space-time method of fundamental solutions(LSTMFS)is extended for solving three-dimensional transient diffusion problems in this *** interval segmentation in temporal direction is developed for the accurate simulation of long-time-dependent diffusion *** the LSTMFS,the whole space-time domain with nodes arranged i divided into a series of overlapping subdomains with a simple *** each subdomain,the conventional method of fundamental solutions is utilized and the coefficients associated with the considered domain can be explicitly *** calculating a combined sparse matrix system,the value at any node inside the space-time domain can be *** experi-ments demonstrate that high accuracy and efficiency can be simultaneously achieved via the LSTMFS,even for the problems defined on a long-time and quite complex computational domain.

关键词： Localized spacetime method of fundamental solutions Meshless method Long-time evolution Transient diffusion

Plasticity-induced stacking fault behaviors ofγ'precipitates in novel CoNi-based superalloys

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第31期90卷 20-29页

作者： w.-w.Xu G.H.Yin Z.Y.Xiong q.Yu T.q.Gang L.J.chen School of Aerospace Engineering Xiamen UniversityXiamen 361005China

Implementation of novelγ/γ'Co-based superalloys with higher strength and improved creep durability is a challenging task for *** lack of atomic-level understanding of plastic deformation behavior has seriously limited the exploration of the full capacity of Co-based *** put forward a comprehensive study of generalized stacking fault energies by first principles to explore the effect of Ni and Al/w on the plastic deformation mechanism ofγ'precipitates in Co-based *** is found that alloying Ni and adjusting Al/w obviously change the dislocation glide and twinning nucleation in theγ'precipitates by altering the stable fault energies and the unstable fault energy *** addition of either Ni or w deteriorates the strength even the stability of *** ratio of effective planar fault energy(ΔEp)bridges intrinsic energy barriers and various deformation mechanisms of superalloys at elevated *** for alloying effects,the grain orientation also significantly governs the operation of the plastic deformation of *** theoretical results agree with the available measurements and well capture the observed phenomena in experiments.

关键词： Co-based superalloys Stacking fault energy Creep resistance First-principles method

Precipitation on stacking faults in Mg–9.8wt%Sn alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2020年第10期42卷 230-240页

作者： C.q.Liu C.He H.w.chen J.F.Nie International Joint Laboratory for Light Alloys(Ministry of Education) College of Materials Science and EngineeringChongqing UniversityChongqing400044China Department of Materials Science and Engineering Monash UniversityVictoria3800Australia Electron Microscopy Center Chongqing UniversityChongqing400044PR China

In this work,we have systematically investigated precipitation ofβ’-Mg3Sn phase on intrinsic stacking faults I1 and I2 in a Mg-9.8 wt%Sn alloy using aberration-corrected scanning transmission electron *** observed I1 faults are generated by the dissociation of c+a perfect dislocations and bounded by Frank partial dislocations having a Shockley *** ofβ’on I1 involves a shear of 1/3α,similar to its formation directly from theα-Mg ***β’phase often nucleates at one end of an I1 fault due to the interaction between shear strain fields ofβ’and the Shockley component of the Frank partial at that end,and subsequently grows towards the other end of the *** theβ’reaches to the other end,the Shockley partial bounding the lengthening end of theβ’reacts with the Frank partial bounding the fault,generating an a perfect dislocation that can glide away from the precipitate and the *** observed I2 faults are generated by the dissociation of a perfect dislocations and bounded by Shockley *** ofβ’on I2 does not need a shear of 1/3α,since the pre-existing I2 fault already provides an ABCA four-layer structure ofβ’.Thickening of theβ’that has already formed on the I2 involves the successive occurrence of three crystallographically equivalent shears of 1/3αon every second(0002)αplane of theα-Mg *** this thickening mechanism is similar to that of theβ’formed directly from theα-Mg matrix,an a perfect dislocation will be produced when theβ’is thickened to eight layers,and it can again glide away from the precipitate and the fault.

关键词： Heterogeneous precipitation HAADF-STEM Shockley partial dislocation Frank partial dislocation Dislocation reaction

SEPARATION　CHARACTERISTICS　OF　THE　HYDROCYCLONE　wITH　A　CENTRAL　CONE　AND　ANNULAR　TEETH

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 1996年第4期6卷 11-15页

作者： Chu, LY chen, wM Luo, q NORTHEASTERN UNIV DEPT MINERAL ENGN SHENYANG 110006 PEOPLES R CHINA SICHUAN UNION UNIV DEPT CHEM PROC MACHINERY CHENGDU 610065 PEOPLES R CHINA

ＳＥＰＡＲＡＴＩＯＮＣＨＡＲＡＣＴＥＲＩＳＴＩＣＳＯＦＴＨＥＨＹＤＲＯＣＹＣＬＯＮＥＷＩＴＨＡＣＥＮＴＲＡＬＣＯＮＥＡＮＤＡＮＮＵＬＡＲＴＥＥＴＨ￥ＣｈｕＬｉａｎｇｙｉｎ；ＣｈｅｎＷｅｎｍｅｉ（Ｄｅｐａｒｔｍｅｎｔｏ... 详细信息

ＳＥＰＡＲＡＴＩＯＮＣＨＡＲＡＣＴＥＲＩＳＴＩＣＳＯＦＴＨＥＨＹＤＲＯＣＹＣＬＯＮＥＷＩＴＨＡＣＥＮＴＲＡＬＣＯＮＥＡＮＤＡＮＮＵＬＡＲＴＥＥＴＨ￥ＣｈｕＬｉａｎｇｙｉｎ；ＣｈｅｎＷｅｎｍｅｉ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｃａｌＰｒｏｃｅｓｓｉ...

关键词： ydrocyclone central cone annular teeth separation sharpness classification efficiency separation characteristics