检索结果-南通市图书馆

Acta Metallurgica Sinica(English Letters) 2000年第4期13卷 937-943页

作者： J.M. Hu H.M. Meng d.b. sun S.J. Zhang J.X. Wu and d.J. Yang beijing Corrosion and Protection Center, Open Laboratory of Corrosion, Erosion and Surface Technology, University of Science and Technology beijing, beijing 100083, China beijing Univ of Science and Technology Beijing China

Service life of two different oxide anodes in phenolsulfonic acid (PSA) solution was investigated.b. accelerated electrolysis. The durability of Ti/IrO_2+Ta_2 O_5 anode increased.b. the addition of SnO_2 in the mixed oxides. The degradation mechanisms of Ti/IrO_2+ Ta_2 O_5 and Ti/IrO_2 +Ta_2 O_5 +SnO+2 anodes were different. It was shown from the observation of scanning electron microscopy (SEM) and the electrochcmical measurement that, the deactivation of Ti/IrO_2 + Ta_2 O_5 anode was due to the build-up of an organic film on surface. The growth of the covered film on surface was restricted.b. addition of SnO_2, which resulted in increasing of the service life of anodes. The over-potential for oxygen evolution on Ti/IrO_2 +Ta_2 O_5 electrode increased after doping SnO_2, and the intermediate products of PSA building-up on the surface was much more rapidly oxidized. Meanwhile, a certain part of the surface oxide deposit entered into the solution leading to loss of oxides, which resulted in degradation of Ti/IroO_2 + Ta_2 O_5 anode containing SnO_2 component.

关键词： metal oxide anode IrO_2 + Ta_2 O_5 IrO_2 + Ta_2 O_5 +SnO_2 phenolsulfonic acid degradation

INVESTIGATION OF SURFACE MORPHOLOGY, STRUCTURE ANd ELECTROCATALYTIC PROPERTIES FOR O_2 EVOLUTION OF TITANIUM bASEd IrO_2+Ta_2O_5 COATINGS

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2000年第3期13卷 849-856页

作者： J.M Hu J.X. Wu H.M Meng YR. Zhu d.b. sun and d.J. Yang(beijing Corrosion and Protection Center, Open Laboratory of Corrosion, Erosion and Surface Technology,University of Science and Technology beijing, beijing 100083, China) Univ of Science and Technology Beijing Beijing China

Titanium based IrO2 +Ta2O5 oxide anodes with different compositions and pyrolysis temperatures were prepared.b. termodecompoisition method. by using X-ray diffraction (XRd), the structure and texture coefficient of the coatings, TC(hkl), of IrO2 rutile crystal have been tested. It showed that, the crystallization processes of IrO2 and Ta2O5 in xIrO2 +(100-x) Ta2 O5 (x is in mol%) films affected and confined each *** the mixed system, IrO2 rutile phase existed as a solid solution with Ta, and attained the maximum solubility when x=70mol%, i.e. for the coating of 70% IrO2 +*** the coatings of low iridium content or at low preparing tem pemture, (110) and (101) pwtered orientations were dominant. However, preferred growth of IrO2 weakened with increasing either iridium content or temperature. Three typical surface morphologies were observed.b. using scanning electron tnicroscopy(SEM). The crystallite size of the mixed oxide coatings were finest for the the film of 70%IrO2 +30%Ta2O5,and decreased with the pyrolysis tempemture. As the results of the finest crystallite segregating on sudece and the maxitnum solid solubility of Ir and Ta component in deposits, the coatings with the composition of 70%IrO2 +Ta2O5 prepared at 450℃ presented the mdrimutn electrocatalgtic activitg for O2 evolution in 0. 5M H2SO4 *** to 550℃, Ti base suffered to oxidation resulting in decreasing anode conductivity,therefore, coatings performed a low activity.

关键词： titanium based coating anode iridium oxide tantalum oxide,solid solution crystallite orientation electrocatalytic activity

Air purifier or fresh air system?A comparison of energy consumption and cost in urban China residential buildings

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第9期67卷 2637-2647页

作者： GUO Yong sun ZhiWei WESCHLER Louise b ZHANG YinPing department of building Science Tsinghua UniversityBeijing 100084China beijing Key Laboratory of Indoor Air Quality Evaluation and Control Beijing 100084China Independent Researcher Colts Neck 07722NJUSA

Chinese urban residential buildings face serious indoor air quality *** purification systems(e.g.,air purifiers,fresh air systems)that supply fresh air or purify indoor air are widely used in residential buildings to improve indoor air *** the challenges of energy conservation and emission reduction,it is urgent to guide residents on choosing appropriate air purification *** key problem is how to identify the best air purification system with the lowest energy consumption or operating *** of air purification systems have rarely been conducted on the premise that they should deliver air such that the main indoor pollutant concentrations all meet air quality *** ignored in comparisons are the increased filtration resistance caused.b. dust accumulation on the filter and the cost of filter *** this study,we propose a method to compare residential air purification systems based on energy consumption and total cost,and we provide methods to select air purification systems in China's different climatic *** used a standard two-person bedroom as the example,and determined the most suitable(minimum cost or energy consumption)air purification systems for the capital cities of the provinces in Chinese mainland.

关键词： IAQ fresh air system air purifier energy consumption cost

degeneration of foundation cushion species induced.b. ecological constraints can cause massive changes in alpine plant communities

在线全文

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2024年第4期67卷 789-802页

作者： Jianguo Chen Xufang Chen Lishen Qian Yazhou Zhang bo Li Honghua Shi Lu sun Christian Schöb Hang sun Key Laboratory for Plant diversity and.b.ogeography of East Asia Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China University of Chinese Academy of Sciences Beijing 100049China College of Resources and Environment Yunnan Agricultural UniversityKunming 650500China Área de biodiversidad y Conservación Universidad Rey Juan CarlosMóstoles 28933Spain

Foundational cushion plants can re-organize community structures and sustain a prominent proportion of alpine biodiversity,but they are sensitive to climate *** loss of cushion species can have broad consequences for associated *** potential plant community changes with the population dynamics of cushion plants remain,however,*** eight plant communities along a climatic and community successional gradient,we assessed cushion population dynamics,the underlying ecological constraints and hence associated plant community changes in alpine communities dominated.b. the foundational cushion plant Arenaria *** population dynamics of Arenaria are attributed to ecological constraints at a series of life history *** functions are constrained.b. increasing associated.b.neficiary plants;subsequent seedling establishment is constrained.b. temperature,water and light availability,extreme climate events,and interspecific competition;strong competitive exclusion may accelerate mortality and degeneration of cushion *** with cushion dynamics,species composition,abundance and community structure gradually *** cushion plants completely degenerate,previously cushion-dominated communities shift to relatively stable communities that are overwhelmingly dominated.b. *** warming may accelerate the degeneration process of *** of this foundational cushion plant will possibly induce massive changes in alpine plant communities and hence ecosystem functions in alpine *** assessment of the population dynamics of foundation species is critical for an effective conservation of alpine biodiversity.

关键词： alpine ecosystem biodiversity change climate change plant community dynamics foundation species global warming population dynamics

What diameter?What height?Influence of measures of average tree size on area-based allometric volume relationships

在线全文

学校读者我要写书评

暂无评论

Forest Ecosystems 2024年第1期11卷 100-109页

作者： Yilin Wang John A.Kershaw Mark J.ducey Yuan sun James b.McCarter Integrated Forest Mensuration and Systems Analysis Laboratory Faculty of Forestry and Environmental ManagementUniversity of New BrunswickFrederictonNBCanada department of Natural Resources and the Environment University of New HampshireDurhamNHUSA College of Forestry Nanjing Forestry UniversityNanjing210037China Scientific Programmer RayonierYuleeFLUSA

Volume is an important attribute used in many forest management *** from 83 fixed-area plots located in central New brunswick,Canada,are used to examine how different measures of stand-level diameter and height influence volume prediction using a stand-level variant of Honer's(1967)volume *** density was included in the models(Volume=f(diameter,Height,density))choice of diameter measure was more important than choice of height *** density was not included(Volume=f(diameter,Height)),the opposite was *** models with density included,moment-based estimators of stand diameter and height performed.b.tter than all other *** models without density,largest tree estimators of stand diameter and height performed.b.tter than other *** overall best equation used quadratic mean diameter,Lorey's height,and density(root mean square error=5.26 m^3·ha^(-1);1.9%relative error).The best equation without density used mean diameter of the largest trees needed to calculate a stand density index of 400 and the mean height of the tallest 400 trees per ha(root mean square error=32.08 m^(3)·ha^(-1);11.8%relative error).The results of this study have some important implications for height subsampling and LidAR-derived forest inventory analyses.

关键词： Allometric relationships Stand structure Volume estimation Stand-level attributes

ONE-PARAMETER FINITE dIFFERENCE METHOdS ANd THEIR ACCELERATEd SCHEMES FOR SPACE-FRACTIONAL SINE-GORdON EQUATIONS WITH dISTRIbUTEd dELAY

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2024年第3期42卷 705-734页

作者： Tao sun Chengjian Zhang Haiwei sun School of Mathematics and Statistics Huazhong University of Science and TechnologyWuhan 430074China Hubei Key Laboratory of Engineering Modeling and Scientific Computing Huazhong University of Science and TechnologyWuhan 430074China department of Mathematics University of MacaoMacaoChina

This paper deals with numerical methods for solving one-dimensional(1d)and twodimensional(2d)initial-boundary value problems(IbVPs)of space-fractional sine-Gordon equations(SGEs)with distributed *** 1d problems,we construct a kind of oneparameter finite difference(OPFd)*** is shown that,under a suitable condition,the proposed method is convergent with second order accuracy both in time and *** implementation,the preconditioned conjugate gradient(PCG)method with the Strang circulant preconditioner is carried out to improve the computational efficiency of the OPFd *** 2d problems,we develop another kind of OPFd *** such a method,two classes of accelerated schemes are suggested,one is alternative direction implicit(AdI)scheme and the other is AdI-PCG *** particular,we prove that AdI scheme can arrive at second-order accuracy in time and *** some numerical experiments,the computational effectiveness and accuracy of the methods are further ***,for the suggested methods,a numerical comparison in computational efficiency is presented.

关键词： Fractional sine-Gordon equation with distributed delay One-parameter finite difference methods Convergence analysis AdI scheme PCG method

Compressive property and energy absorption characteristic of interconnected porous Mg-Zn-Y alloys with adjusting Y addition

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 Magnesium and Alloys 2024年第1期12卷 171-185页

作者： J.A.Liu S.J.Liu b.Wang W.b.sun X.J.Liu Z.W.Han College of Materials Science and Engineering Key Laboratory of Automobile Materials(Ministry of Education)Jilin UniversityChangchun 130022PR China Key Laboratory of bionic Engineering(Ministry of Education) College of Biological and Agricultural EngineeringJilin UniversityChangchun130022PR China Weihai Institute for bionics-Jilin University Weihai 264205PR China

In this study,interconnected porous Mg-2Zn-xY alloys with different phase compositions were prepared.b. various Y additions(x=0.4,3,and 6 wt.%)to adjust the compressive properties and energy absorption *** characterization methods were then applied to identify the microstructure of the porous Mg-Zn-Y and describe the details of the second *** tests were performed at room temperature(RT),200℃,and 300℃to study the impact of the Y addition and testing temperature on the compressive properties of the porous *** experimental results showed that a high Y content promotes a microstructure refinement and increases the volume fraction of the second *** the Y content increases,different Mg-Zn-Y ternary phases appear:I-phase(Mg_(3)Zn_(6)Y),W-phase(Mg_(3)Zn_(3)Y_(2)),and LPSO phase(Mg_(12)ZnY).When the Y content ranges between 0.4%and 6%,the compressive strength increases from 6.30MPa to 9.23 MPa,and the energy absorption capacity increases from 7.33 MJ/m^(3)to 10.97 MJ/m^(3)at RT,which is mainly attributed to the phase composition and volume fraction of the second ***,the average energy absorption efficiency is independent of the Y *** addition,the compressive deformation behaviors of the porous Mg-Zn-Y are altered.b. the testing *** compressive strength and energy absorption capacity of the porous Mg-Zn-Y decrease due to the softening effect of the high temperature on the *** deformation behaviors at different temperatures are finally observed to reflect the failure mechanisms of the struts.

关键词： Porous magnesium Rare earth elements Microstructure Compressive behavior Energy absorption characteristic

The Functional Redundancy of Neddylation E2s and E3s in Modulating the Fitness of Regulatory T Cells

在线全文

学校读者我要写书评

暂无评论

Research 2024年第2期2023卷 373-387页

作者： di Wu Yi sun Cancer Institute(Key Laboratory of Cancer Prevention and Intervention China National Ministry of Education)of the Second Affiliated Hospital and Institute of Translational MedicineZhejiang University School of MedicineHangzhou 310029China Cancer Center of Zhejiang University Hangzhou 310029China Zhejang Provincial Clinical Research Center for Cancer Zhejang ProvinceChina Key Laboratory of Molecular biology in Medical Sciences Zhejang ProvinceChina Research Center for Life Science and Human Health Binjiang Institute of Zhejiang UniversityHangzhou 310053China

Neddylation is necessary for activation of Cullin-RING ligases(CRLs),which degrade various immune regulatory *** recent study showed that while depletion of neddylation E2-E3 pair Ube2f-Sag in regulatory T(T_(reg))cells had no obvious phenotype,the same depletion of either Ube2m or Rbx1 caused inflammation disorders with different *** these E2s or E3s compensate each other in functional regulations of T_(reg)cells is,however,previously *** this report,we generated Foxp3^(Cre);Ube2m^(fl/fl);Ube2f^(fl/fl)or Foxp3^(Cre);Rbx1^(fl/fl);Sag^(fl/fl)double-null mice by simultaneous deletion of both neddylation E2s or E3s in T_(reg)cells,***,Ube2m&Ube2f double-null mice developed much severe autoimmune phenotypes than did Ube2m-null mice,indicating that Ube2m markedly compensates Ube2f in T_(reg)*** minor worsened autoimmune phenotypes seen at the very early stage in Rbx1&Sag double-null than Rbx1-null mice is likely due to already severe phenotypes of the later,indicating a minor compensation of Rbx1 for *** RNA profiling-based analyses revealed that up-and down-regulations of few signaling pathways in T_(reg)cells are associated with the severity of autoimmune ***,severer inflammation phenotypes seen in mice with double E3-null than with double E2-null T_(reg)cells indicate a neddylation-independent mechanism of 2 E3s,also known to serve as the RING component of CRLs in regulation of T_(reg)cell fitness.

关键词： Foxp3 inflammation markedly

Rational surface charge engineering of haloalkane dehalogenase for boosting the enzymatic performance in organic solvent solutions

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

Chinese Journal of Chemical Engineering 2024年第1期65卷 276-285页

作者： Yin Wu Yan sun department of biochemical Engineering School of Chemical Engineering and Technology and Key Laboratory of Systems Bioengineering and Frontiers Science Center for Synthetic Biology(Ministry of Education)Tianjin UniversityTianjin 300350China

biocatalysis in organic solvents(OSs)has numerous important applications,but native enzymes in OSs often exhibit limited catalytic ***,we proposed a computation-aided surface charge engineering strategy to improve the catalytic performance of haloalkane dehalogenase dhaA in OSs based on the energetic analysis of substrate binding to the dhaA *** variants with enhanced OS resistance were obtained.b. replacing negative charged residues on the surface with positive charged residue(Arg).Particularly,a four-substitution variant E16R/E93R/E121R/E257R exhibited the best catalytic performance(five-fold improvement in OS resistance and seven-fold half-life increase in 40%(vol)dimethylsulfoxide).As a result,the overall catalytic performance of the variant could.b. at least 26 times higher than the wild-type *** spectroscopy and molecular dynamics simulation studies revealed that the residue substitution mainly enhanced OS resistance from four aspects:(a)improved the overall structural stability,(b)increased the hydrophobicity of the local microenvironment around the catalytic triad,(c)enriched the hydrophobic substrate around the enzyme molecule,and(d)lowered the contact frequency between OS molecules and the catalytic *** findings validate that computationaided surface charge engineering is an effective and ingenious rational strategy for tailoring enzyme performance in OSs.

关键词： Surface charge engineering Organic solvent resistance Molecular dynamics simulation Haloalkane dehalogenase

Turbulence Statistics of Thermo-buoyancy Supercritical Fuel Flow in a Regenerative Cooling Channel

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2024年第1期33卷 126-137页

作者： sun Feng XIE Gongnan School of Marine Science and Technology Northwestern Polytechnical UniversityXi'an 710072China department of Thermal Engineering Tsinghua UniversityBeijing 100084China

Active regenerative cooling with supercritical hydrocarbon fuel is considered as the most promising thermal protection *** existence of buoyancy force would lead to strongly anisotropic flow and thermal transport *** is closely related to the cooling performance of the *** elucidate the mechanisms of turbulent transport,the large eddy simulation(LES) was performed to assess turbulence statistics within different turbulence *** results indicated that the buoyancy and inertial force together dominated the change of turbulent ***,the spatial thermal buoyancy effect significantly suppressed the vertical velocity *** is due to the laminar motion caused.b. the buoyancy force,thereby weakening the thermal *** the statistics of velocity fluctuation,it was found that the buoyancy force and inertial force greatly weaken the vertical and streamwise velocity fluctuation,*** the statistics of thermal transport,the results pointed out that the near-wall heat transport characteristics need to be paid more *** thickness of the temperature mixing boundary layer led to the attenuation of vertical heat flux,which inhibited vertical temperature diffusion and predisposed to extreme conditions of heat transfer *** results can enhance the academic understanding of the heat transfer mechanism of supercritical fluids,and give guidance for further applications of thermal protection.

关键词： active regenerative cooling large eddy simulation(LES) buoyancy force turbulence statistics