检索结果-南通市图书馆

Current Transport in Copper Schottky Contacts to a−Plane/ c−Plane n-Type MoSe_(2)

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2011年第8期28卷 254-257页

作者： C.K.Sumesh K.D.Patel V.M.Pathak r.Srivastav Department of Physics Faculty of Technology and EngineeringCharotar University of Science and TechnologyCHANGA 388421GujaratIndia Department of Physics Sardar Patel UniversityVallabh Vidyanagar 388120GujatatIndia

We identically prepared Cu-nMoSe_(2)(a−plane)and Cu-nMoSe_(2)(c−plane)Schottky barrier diodes(SBDs)on the same n-type MoSe_(2) single *** effective Schottky barrier heights(SBHs)and ideality factors were obtained from the current−voltage-temperature(I–V–T)*** barrier height and ideality factor,estimated from the conventional thermionic emission model by assuming a Gaussian barrier distribution,are highly dependent on temperature.A notable deviation from the theoretical richardson constant value is also observed in the conventional richardson *** decrease in the experimental barrier heightΦB0 and an increase in the ideality factor n with a decrease in temperature have been explained on the basis of barrier height inhomogeneities at the metal−semiconductor *** is proven that the presence of a distribution of barrier heights is responsible for the apparent decrease of the zero bias barrier *** voltage dependence of the standard deviation causes the increase of the ideality factor at low *** value of the richardson constant obtained without considering the inhomogeneous barrier heights is much closer than the theoretical *** Cu-nMoSe_(2)(a−plane)Schottky diode shows better results in comparison with the nMoSe_(2)(c-plane)Schottky diode.

关键词： Schottky temperature ideality

MODIFICATION OF SODIUM SALT OF PArTIALLY CArBOXYMETHYLATED TAMArIND KErNEL POWDEr THrOUGH GrAFTING WITH ACrYLONITrILE: SYNTHESIS, CHArACTErIZATION AND SWELLING BEHAVIOr

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 Polymer Science 2013年第12期31卷 1670-1684页

作者： J.H.Trivedi J.r.Jivani K.H.Patel H.C.Trivedi P.G.Dept.of Chemistry Sardar Patel UniversityVallabh Vidyanagar Amneal Phamaceuticals

A graft copolymer of polyacrylonitrile （PAN） with sodium salt of partially carboxymethylated tamarind kernel powder （Na-PCMTKP, DS ^-= 0.15） was synthesized by using ceric ammonium nitrate （CAN） as a redox initiator in an aqueous medium. The optimum reaction conditions for affording maximum percentage of grafting were established by successively varying reaction conditions such as concentrations of nitric acid, CAN, monomer （AN） as well as reaction time, temperature and amount of substrate. The influence of these reaction conditions on the grafting yields was discussed. The kinetic scheme of free radical graft copolymerization was proposed and the experimental results were found to agree very well with the proposed kinetic scheme. The graft copolymer （Na-PCMTKP-g-PAN, percentage of grafting G = 413.76% and percentage of grafting efficiency GE = 96.48%） sample synthesized under the established optimized reaction conditions was hydrolyzed by 0.7 mol-L l NaOH solution at 90-95 ℃ to yield the superabsorbent hydrogel, H-Na-PCMTKP-g-PAN. The swelling behavior of the hydrogel was studied by carrying out its absorbency measurements in low conductivity water, 0.15 mol·L^-1 salt （NaCl, CaCl2 and AlCl3） solutions and simulated urine （SU） solution at different timings. FTIr, TGA and SEM techniques were used to characterize the products.

关键词： Sodium salt of partially carboxymethylated tamarind kernel powder Acrylonitrile Graft copolymerization Superabsorbent hydrogels Swelling behavior.

STUDY　OF　INTErACTION　BETWEEN　VOrTICES　AND　A　FrEE　SUrFACE　PArT　Ⅱ：INTErACTION　OF　DOUBLE　VISCOUS　VOrTEX　DIPOLES　WITH　A　FrEE　SUrFACE

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 1995年第1期7卷 17-32页

作者： Wu Chui-jie Tan Bo-yan (Air Force Institute of Meteorology,Nanjing 211101 P. r. China)Ma Hui-yang(Graduate School of Academia Sinica, Beijing 100039 P. r. China)( Air Force Inst of Meteorology Nanjing China

In this paper the VOF (Volume of Fluid) method is used to numerically study the interaction of double viscous vortex dipoles with free surface in a two dimensional incompressible flow field. From the results of this research, it is found that the general consequence of the interaction is qualitatively equivalent to the problem of a single vortex dipole interacts with a free surface.

关键词： vortex motion free surface computational fluid mechanics.

Flexural behavior of reinforced concrete beams with high performance fiber reinforced cementitious composites

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2019年第9期26卷 2609-2622页

作者： SIVA Chidambaram r PANKAJ Agarwal CSIr-Central Building research Institute Roorkee 247667India Department of Earthquake Engineering Indian Institute of Technology RoorkeeRoorkee 247667India

This article presents an experimental study on the flexural performance of reinforced concrete(rC)beams with fiber reinforced cementitious composites(FrCC)and hybrid fiber reinforced cementitious composites(HFrCC)in the hinge *** specimens with moderate confinement were used in the study and tested under monotonic *** diverse types of FrCC including hybrid composites using fibers in different profiles and in different volumes are employed in this *** specimens such as cylindrical specimens and prism specimens are also used to study the physical properties of composites *** moment?curvature,stiffness behavior,ductility,crack pattern and modified flexural damage ratio are the main factors considered in this study to observe the efficacy of the employed hybrid *** experimental outputs demonstrate the improved post yield behavior with less rate of stiffness degradation and better damage tolerance capacity than conventional technique.

关键词： reinforced concrete beams fiber reinforced composites flexural behavior flexural damage ratio

Synthesis and Characterization of Zinc Succinate, Zn(C4H4O4)

在线全文

学校读者我要写书评

暂无评论

Chemical research in Chinese Universities 2001年第1期17卷 20-25页

作者： ZHENG Yue qing ** (Institute for Solid State Chemistry, Ningbo University, Ningbo 315211, P. r. China) 宁波大学浙江宁波 315211 Max-Planck Institute fur Festkor per forschung 德国 D-70569

PETErS Karl and von SCHNErING Hans Georg (Max Planck Institute für Festkrperforschung, D 70569 Stuttgart, Germany)Zn(C 4H 4O 4) prepared by dissolving 0.483 g (1.41 mol) of Zn 3(OH) 4CO 3·H 2O and 0.5 g (4.23 mol) of C 4H 6O 4 in 50 mL of H 2O followed by slow evaporation at room temperature crystallizes in the monoclinic space group C 2 with the cell parameters a =0.757 9(1) nm, b =0.597 6(1) nm , c =0.626 5(1) nm, β =108.45(1)°, V =0.269 17(7) nm 3, D x=2.239 \{g/cm 3\}, Z =2 and the final r(F o)=0.039 and wr(F o 2)=0.088 for 396 reflections [ F o 2≥2 σ(F o 2)]. In the crystal structure unit, each Zn is tetrahedrally coordinated by four O atoms from four (C 4H 4O 4) 2- anions, each of which, in turn, bridges four Zn atoms to build up a 3D \{\} 3 ∞[Zn(C 4H 4O 4) 4/4 ] network. The thermal analyses indicate that Zn(C 4H 4O 4) is stable below 420 ℃.

关键词： Synthesis Zinc succinate Crystal structure Thermal decomposition

单通道和多通道毛细管光学元件-技术发展水平和应用(英文)

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

光学精密工程 2007年第12期15卷 1932-1945页

作者： A Bjeoumikhov r Wedell S Bjeoumikhova IfG Institute for Scientific Instruments GmbH 12489 BerlinRudowerChaussee 29/31Germany Institut für angewandte Photonik e.V. 12489 BerlinRudowerChaussee 29/31Germany Bundesanstalt für Materialforschung und-prüfung 12200 BerlinGermany

毛细管光学元件在X射线分析中的应用已有20多年的历史,在这段时间里,毛细管光学元件的制作技术发生了很大的变化。上世纪90年代初,使用的是组装的毛细管光学元件,目前,集成的多通道毛细管光学元件已广泛地应用于市场销售的X射线分析设... 详细信息

毛细管光学元件在X射线分析中的应用已有20多年的历史,在这段时间里,毛细管光学元件的制作技术发生了很大的变化。上世纪90年代初,使用的是组装的毛细管光学元件,目前,集成的多通道毛细管光学元件已广泛地应用于市场销售的X射线分析设备中。这些元件的毛细管直径在微米量级,其光学性质可以根据几何光学的光线追迹计算进行描述。最近,由于多通道毛细管制作技术的改进,已成功制成了200 nm及以下通道尺寸的毛细管光学元件。在这样小的通道尺寸下,观察到了X射线辐射的波动效应。最后文章介绍了毛细管光学元件在X射线微荧光分析和微衍射方面的应用。

关键词： X射线毛细管光学元件波动特性纳米毛细管 X射线分析

Gold and Base Metals Associated with Uranium Mineralization in Some Lower Carboniferous rock Units in the Wadi Abu El Mogheirat Area, Southwestern Sinai, Egypt

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2021年第6期95卷 2087-2099页

作者： Osama r.SALLAM Abdalla S.ALSHAMI Abd Elhadi A.ABBAS E.GUIBAL Nuclear Materials Authority CairoEgypt Institut Mines Telecom-Mines Ales Centre des Materiaux des Mines d’AlesUniversityMontpellierFrance

The Lower Carboniferous sediments at Wadi Abu El Mogheirat consist of four stratigraphic formations, from base upwards: Um Bogma, El Hashash, Magharet El Maiah and Abu Zarab formations. The most-concentrated radioactive anomalies at Wadi Abu El Mogheirat are in the middle member of the Um Bogma Formation. The gibbsitic marl in this formation shows the highest uranium contents(around 710 ppm). Gibbsitic marl and black gibbsite of the middle Um Bogma Formation show higher enrichment in Co, Cu, Mn, Ni, Pb, Zn, U, V, Ce and Th. Black gibbsite contains the highest total rare earth elements concentration, especially in terms of LrEEs, while gibbsitic marl contains the highest content of HrEEs. Anomalous contents of gold at Wadi Abu El Mogheirat are recorded for the first time in the gibbsitic marl(content: 10.4 ppm), black gibbsite(2.8 ppm) of the middle member of the Um Bogma Formation and in the siltstones of the El Hashash Formation(0.6 ppm). Gibbsitic marl shows the presence of uranothorite, celestite, zircon, atacamite, barite, xenotime and rutile. These characteristic demonstrate that the middle member of the Um Bogma Formation constitutes a potential source for gold. This conclusion is reinforced by the potential to exploit other metals such as Co, Cu, Mn, Ni, Pb, Zn, U, V, Th and Ce as by-products.

关键词： gibbsite rare earth elements Um Bogma

User-friendly finite element design of main entries, barrier pillars,and bleeder entries

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2018年第1期28卷 3-10页

作者： William G.Pariseau Mark K.Larson Heather E.Lawson Douglas r.Tesarik Department of Mining Engineering University of Utah Spokane Mining research Division NIOSH

This contribution describes development and application of a user-friendly finite element program,UT3PC, to address three important problems in underground coal mine design:(1) safety of main entries,(2) barrier pillar size needed for entry protection, and(3) safety of bleeder entries during the advance of an adjacent longwall *** the finite element method is by far the most popular engineering design tool of the digital age, widespread use by the mining community has been impeded by the relatively high cost of and the need for lengthy specialized training in numerical *** of UT3PC overcomes these impediments in three easy ***, a material properties file is prepared for the considered ***, mesh generation is automatic through an interactive process.A third and last step is simply execution of the *** using data from several western coal mines illustrate the ease of using the application for analysis of main entries, barrier pillars, and bleeder entry safety.

关键词： Finite element Coal Mine layout design Main entries Barrier pillars Bleeder entries

Effects of rare Earth Elements on the Characteristics of Low Temperature Plasma Nitrocarburized Martensitic Stainless Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2012年第11期28卷 1046-1052页

作者： r.L.Lju Y.J.Qiao M.F.Yan Y.D.Fu College of Materials Science and Chemical Engineering Harbin Engineering UniversityHarbin 150001China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China

Low temperature plasma nitrocarburizing of 17-4PH martensitic stainless steel was conducted at 430 ℃ with and without rare earth （rE） addition. The microstructure, kinetics, microhardness, wear behavior as well as corrosion resistance of the modified layer were studied by optical microscopy, X-ray diffraction, Vickers microhardness tester, pin-on-disc tribometer and potentiodynamic polarization tests. The results show that the thickness of plasma rE nitrocarburized layer is much thicker than that formed by nitrocarburizing without rE addition. The incorporation of rE does not change the kind of the phases and the nitrocarburized layer consists mainly of nitrogen and carbon expanded martensite （aN）, γ-Fe4N and a-Fe with a trace of CrN phases. The surface microhardness of plasma nitrocarburized layer can be increased by 100 HV after rE addition. Wear resistance of the specimen can be apparently improved by low temperature plasma nitrocarburizing with and without rE addition and without sacrificing its corrosion resistance. Wear reduction effect of low temperature plasma nitrocarburizing with rE addition is better than that of the conventional one.

关键词： Stainless steel Low temperature Plasma nitrocarburizing rare earth (rE) Wear and friction