检索结果-南通市图书馆

Microstructure and brazing mechanism of porous Si_3N_4/Invar joint brazed with Ag-Cu-ti/Cu/Ag-Cu multi-layered filler

在线全文

学校读者我要写书评

暂无评论

journal of Materials Science & technology 2018年第4期34卷 713-719页

作者： j.Zhang j.Y.Liu t.P.Wang School of Materials Science and Engineering Harbin Institute of Technology

Porous Si3N4 was brazed to Invar alloy in this study, and Ag-Cu-ti/Cu/Ag-Cu multi-layered filler was designed to inhibit the formation of Fe2ti and Ni3ti intermetallic compounds. the effects of the brazing temperature and the thickness of Cu interlayer on the microstructure and mechanical properties of brazed joints were investigated. the typical microstructure of the joint brazed with multi-layered filler was porous Si3N4/tiN ＋ ti5Si3/Ag-Cu eutectic[Cu[Ag-Cu eutectic/Cu-rich layer ＋ diffusion layer/Invar. When the brazing temperature increased, the reaction layer at the ceramic/filler interface grew thicker and the Cu interlayer turned thinner. As the thickness of Cu interlayer increased from 50 to 150 μm, the joint strength first increased and then decreased. In this research, the maximum shear strength （73 MPa） was obtained when being brazed at 1173 K with a 100 μm Cu interlayer applied in the filler, which was 55% higher than that brazed with single Ag-Cu-ti brazing alloy and had reached 86% of the ceramic. the release of residual stress and the barrier effect of Cu interlayer to inhibit the formation of Fe2ti and Ni3ti intermetallics played the major role in the improvement of joint strength.

关键词： Porous Si3N4 Invar alloy Brazing Microstructure Mechanical properties

在线全文

学校读者我要写书评

暂无评论

电子线路分析

电子线路分析

On the polynomiality and asymptotics of moments of sizes for random(n,dn ± 1)-core partitions with distinct parts

作者： j.t.·维特(j.t. Wade)

来源：南通市图书馆图书评论

学校读者我要写书评

暂无评论

Science China Mathematics 2021年第4期64卷 869-886页

作者： Huan Xiong Wenston j.t.Zang Institut de Recherche Mathematique Avancee Universite de Strasbourg et CNRSStrasbourg 67000France Institute of Advanced Study of Mathematics Harbin Institute of TechnologyHarbin 150001China

Amdeberhan’s conjectures on the enumeration,the average size,and the largest size of(n,n+1)-core partitions with distinct parts have motivated many research on this ***,Straub(2016)and Nath and Sellers(2017)obtained formulas for the numbers of(n,dn-1)-and(n,dn+1)-core partitions with distinct parts,*** X_(s,t) be the size of a uniform random(s,t)-core partition with distinct parts when s and t are coprime to each *** explicit formulas for the k-th moments E[X_(n,n+1)^(k)]and E[X_(2 n+1,2 n+3)^(k)]were given by Zaleski and Zeilberger(2017)when k is ***(2017)also studied the expectation and higher moments of X_(n,dn-1) and conjectured some polynomiality properties concerning them in ar Xiv:*** by the above works,we derive several polynomiality results and asymptotic formulas for the k-th moments of X_(n,dn+1) and X_(n,dn-1) in this paper,by studying theβ-sets of core *** particular,we show that these k-th moments are asymptotically some polynomials of n with degrees at most 2 k,when d is given and n tends to ***,when d=1,we derive that the k-th moment E[X_(n,n+1)^(k)]of X_(n,n+1) is asymptotically equal to(n^(2)/10)^(k)when n tends to *** explicit formulas for the expectations E[X_(n,dn+1)]and E[X_(n,dn-1)]are also ***(n,dn-1)-core case in our results proves several conjectures of Zaleski(2017)on the polynomiality of the expectation and higher moments of X_(n,dn-1).

关键词： partition hook length core partition average size distinct part

Changes in South Asian monsoon: New high-resolution paleoclimatic records from tibet, China

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2000年第1期45卷 87-91页

作者： j.t.Overpeck LIU Kambiu j.t.Overpeck Department of Geography and Anthropology Louisiana State UniversityBaton RougeLA 70803USANOAA Paleoclimatology ProgramNational Geophysical Data CenterBoulderCO 80303USANOAA Paleoclimatology Program National Geophysical Data Center Boulder CO 80303 USA

High-resolution pollen records from 6 small lakes in the tibetan Plateau provided the details of evolution of South Asian monsoon since the Last Glacial Maximum. Prior to 16 kaBP, the region was a desert-steppe characterized by cold and dry climates, the january temperature was 7 -10℃lower than that of present and the annual precipitation only accounted for 40% of the present. the temperature and precipitation increased gradually and trees began to live in the region after 12 kaBP, but during the interval from 9.2 to 6.3 kaBP, forest and forest-meadow appeared occasionally. From 8 to 5 kaBP, both january and july temperature was 2-3℃ higher and annual precipitation was also about 200 mm higher than that of the present. After 5 kaBP, temperature and precipitation decreased linearly and steppe vegetation began to degenerate.

关键词： South Asian monsoon pollen records paleovegetation and paleoclimate tibet.

Surface modification of stratum corneum for drug delivery and skin care by microplasma discharge treatment

在线全文

学校读者我要写书评

暂无评论

Plasma Science and technology 2019年第6期21卷 1-8页

作者： j KRIStOF t AOSHIMA M BLAjAN K SHIMIZU Graduate School of Science and technology Shizuoka University 432-8561 Hamamatsu Japan Department of Electrical and Electronic Engineering Shizuoka University 432-8561 Hamamatsu Japan Organization for Innovation and Social Collaboration Shizuoka University 432-8561 Hamamatsu Japan

Human skin is the largest organ and also the main barrier that prevents foreign substances from entering the *** surface properties of the skin are relevant for transdermal drug delivery and *** micropig skin is used as a substitute for human skin.A microplasma electrode is used for surface modification of the skin epidermal layer of the Yucatan *** dielectric barrier discharge has a thin dielectric as a barrier (~50 μm) and a frequency of 25 *** surface properties of the epidermal layer were characterized by the measurement of the contact angle of the water *** effects of different gases such as air,nitrogen,oxygen,helium or argon were *** change of the contact angle is temporal and it is returned to its initial state after several *** the gases used for plasma ignition,oxygen and argon were the most effective for skin *** distance of the skin from the electrode and the treatment time played a crucial roles in the increasing water contact *** of surface atomic concentration were determined by x-ray photoelectron *** microplasma treatment,the oxygen and nitrogen concentration increased at the skin surface.

关键词： microplasma contact angle skin stratum corneum XPS

Strong-form framework for solving boundary value problems with geometric nonlinearity

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2016年第12期37卷 1707-1720页

作者： j.P.YANG W.t.SU Department of Civil Engineering Chiao Tung University

In this paper, we present a strong-form framework for solving the boundary value problems with geometric nonlinearity, in which an incremental theory is developed for the problem based on the Newton-Raphson scheme. Conventionally, the finite ele- ment methods （FEMs） or weak-form based meshfree methods have often been adopted to solve geometric nonlinear problems. However, issues, such as the mesh dependency, the numerical integration, and the boundary imposition, make these approaches com- putationally inefficient. Recently, strong-form collocation methods have been called on to solve the boundary value problems. the feasibility of the collocation method with the nodal discretization such as the radial basis collocation method （RBCM） motivates the present study. Due to the limited application to the nonlinear analysis in a strong form, we formulate the equation of equilibrium, along with the boundary conditions, in an incremental-iterative sense using the RBCM. the efficacy of the proposed framework is numerically demonstrated with the solution of two benchmark problems involving the geometric nonlinearity. Compared with the conventional weak-form formulation, the pro- posed framework is advantageous as no quadrature rule is needed in constructing the governing equation, and no mesh limitation exists with the deformed geometry in the increment al-it erative process.

关键词： geometric nonlinearity incremental-iterative algorithm radial basis collo-cation method (RBCM) strong form

Biological transformation,kinetics and dose-response assessments of bound musk ketone hemoglobin adducts in rainbow trout as biomarkers of environmental exposure

在线全文

学校读者我要写书评

暂无评论

journal of Environmental Sciences 2008年第7期20卷 878-884页

作者： M A Mottaleb j H Zimmerman t W Moy Department of Chemistry and Biochemistry Baylor UniversityP.O.Box 97348WacoTX 76798USA. U.S.Environmental Protection Agency National Exposure Research LaboratoryEnvironmental Sciences Division944 East Harmon AveLas VegasNV 89119USA

Low levels (ng/g) of musk ketone (MK),used as a fragrance additive in the formulation of personal care products,are frequently detected in the water and other ***,aquatic organisms can be continuously exposed to *** this study,kinetics and dose-response assessments of 2-amino-MK (AMK) metabolite,bound to cysteine-hemoglobin (Hb) in rainbow trout,formed by enzymatic nitro-reduction of MK have been *** were exposed to a single exposure of 0.010,0.030,0.10,and 0.30 mg MK/g ***...

关键词： biotransformation kinetics hemoglobin adducts dose-response nitro musks biomarker fish

Review:Resuspension of wall deposits in spray dryers

在线全文

学校读者我要写书评

暂无评论

journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第11期8卷 1762-1774页

作者： HANUS M.j. LANGRISH t.A.G. School of Chemical and Biomolecular Engineering University of Sydney Sydney NSW 2006 Australia

Wall deposition occurs in spray dryers when dried or partially dried particles contact and adhere to the walls during operation, thus reducing the yield of product collected. Wall deposits also present a product contamination risk and a fire or explosion risk when spray drying products that oxidize exothermically, such as milk powder. Re-entrainment is the resuspension of spray dryer wall deposits into the main gas stream for collection as product. Literature suggests that the process for re-entrainment of particles from spray dryer wall deposits is strongly dependent on particle size and gas velocity.

关键词： Wall deposition Spray dryers Dried particles Re-entrainment Adhesive forces

Superplastic behavior of an ultrafine-grained Mg-13Zn-1.55Y alloy with a high volume fraction of icosahedral phases prepared by high-ratio differential speed rolling

在线全文

学校读者我要写书评

暂无评论

journal of Materials Science & technology 2017年第9期33卷 919-925页

作者： t.Y.Kwak W.j.Kim Rare Metal R&BD Group Korea Institute of Industrial Technology Department of Materials Science and Engineering Hongik University

An ultrafine-grained（UFG） Mg-13Zn-1.55 Y alloy（ZW132） with a high volume fraction（7.4%） of icosahedral phase（I-phase, Mg;Zn;Y） particles was prepared by applying high-ratio differential speed rolling（HRDSR） on the cast microstructure following homogenization. the alloy exhibited excellent superplasticity at low temperatures(tensile elongations of 455% and 1021% 473 K-10;s;and 523 K-10;s;,respectively). Compared with UFG Mg-9.25Zn-1.66 Y alloy（ZW92） with a lower volume fraction of I-phase particles（4.1%）, which was prepared using the same processing routes, the UFG ZW132 alloy exhibited a higher thermal stability of grain size. Rapid grain coarsening, however, occurred at temperatures beyond523 K, leading to a loss of superplasticity. the high-temperature deformation behavior of the HRDSRprocessed ZW132 alloy could be well described assuming that the mechanisms of grain boundary sliding and dislocation climb creep competed with each other and considering that the grain-size was largely increased by accelerated grain growth at the temperatures beyond 523 K.

关键词： Magnesium alloy Superplastic deformation Ultrafine grain Icosahedral quasicrystal Grain growth