检索结果-南通市图书馆

Constitutive equation and model validation for a 31 vol.% B_4Cp/6061Al composite during hot compression

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10期34卷 1730-1738页

作者： l. Zhou C. Cui Q.Z. Wang C. li B.l. Xiao Z.y. Ma Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China School of Electromechanical and Vehicle Engineering Yantai University Yantai 264005 China School of Mechanical Engineering Shenyang Ligong University Shenyang 110159 China Nuclear and Radiation Safety Center Ministry of Environmental Protection Beijing 100082 China

An accurate constitutive equation is essential to understanding the flow behavior of B4C/A1 compos-ites during the hot deformation. However, the constitutive equations developed previously in literature are generally for low strain rate deformation. In the present work, we modified the general consti-tutive equation and take the high strain rate correction into account. The constitutive equation for a 31 vol.% B4Cp/6061AI composite was constructed based on the flow stresses measured during isothermal hot compression at temperatures ranging from 375 to 525 ℃ and strain rates from 0.01 to 10 s^-1. The experimental flow stresses were corrected by considering temperature-dependent Arrhenius factor. The modified equation was then verified by using DEFORM-3D finite element analysis to simulate the exper-imental hot compression process. The results show that the modified equation successfully predicts flow stress, load-displacement, and the temperature rise. This helps to optimize the hot deformation process, and to obtain desirable properties, such as reduced porosity and homogenous particle distribution in B4C/AI composites.

关键词： Composites B4C/AI Constitutive equation Hot compression Finite element simulation

A WIND-DRIVEN yEllOW SEA WARM CuRRENT?

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Oceanology and limnology 1987年第4期5卷 289-298页

作者： y.Hsueh Department of Oceanography Florida State university Tallahassee Florida 32306 u.S.A

Observations of current velocity, pressure, and temperature in the eastern yellow Sea during January 10 to April 12, 1986, and geostrophic winds calculated from surface pressure distributions, are analyzed for a study of the synoptic band response of the yellow Sea to the wintertime winds. Currents in shallow coastal waters along a straight portion of the coast are mostly downwind to the south. Along the northern coast sheltered by a large bay, the current is persistently northward. This could be the result of a domination by geostrophic currents associated with an offshore-directed density gradient which is known to form in areas around this location. In the yellow Sea trough, strong upwind flows are found to follow closely surges in the north wind. Co-spectral analyses show that these events are driven by a longitudinal pressure gradient associated with the sea-level set-up along the west coast of South korea under a prevailing north wind.

关键词： A WIND-DRIVEN yEllOW SEA WARM CuRRENT SEA

Modified astrophysical S-factor of 12C+12C fusion reaction at sub-barrier energies

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics C 2020年第11期44卷 189-207页

作者： y.J.li X.Fang B.Bucher k.A.li l.H.Ru X.D.Tang China Institute of Atomic Energy Beijing 102413China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen UniversityZhuhai 519082China Idaho National laboratory Idaho FallsID 83415USA Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China

The 12C+12C fusion reaction plays a crucial role in stellar evolution and *** main open reaction channels includeα,p,n,and *** more than a half century of efforts,large differences remain among the experimental data of this reaction measured using various *** this work,we analyze the existing data using a statistical *** calculation shows the following:1)the relative systematic uncertainties of the predicted branching ratios decrease as the predicted ratios increase;2)the total modified astrophysical S-factors(S^* factors)of the p andαchannels can be obtained by summing the S^* factors of their corresponding ground-state transitions and the characteristicγrays,while taking into account the contributions of the missing channels to the *** applying corrections based on branching ratios predicted by the statistical model,an agreement is achieved among the different data sets at Ecm>4 MeV,while some discrepancies remain at lower energies,suggesting the need for better measurements in the near *** find that the S^* factor recently obtained from an indirect measurement is inconsistent with the direct measurement value at energies below 2.6 *** recommend upper and lower limits for the 12C+12C S^* factor based on the existing models.A new 12C+12C reaction rate is also recommended.

关键词： carbon burning 12C+12C fusion statistical model quasi-molecular resonance astrophysical S-factor reaction rate stellar evolution

Existence of Nondecreasing and Continuous Solutions of an Integral Equation with linear Modification of the Argument

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2007年第9期23卷 1719-1728页

作者： J.CABAllERO B.lóPEZ k.SADARANGANI Departamento de Matemáticas Universidad de Las Palmas de Gran CanariaCampus de Tafira Baja35017 Las Palmas de Gran CanariaSpain

We use a technique associated with measures of noncompactness to prove the existence of nondecreasing solutions to an integral equation with linear modification of the argument in the space C[0, 1]. In the last thirty years there has been a great deal of work in the field of differential equations with a modified argument. A special class is represented by the differential equation with affine modification of the argument which can be delay differential equations or differential equations with linear modifications of the argument. In this case we study the following integral equation x（t） = a（t）＋（Tx）（t） ∫0^σ（t） u（t, s, x（s）, x（λs））ds 0 〈 λ 〈 1 which can be considered in connection with the following Cauchy problem x＇（t） = u（t, s, x（t）, x（λt））, t ∈ [0, 1], 0 〈 λ 〈 1 x（0） = u0.

关键词： measure of noncompactness fixed point theorem nondecreasing solutions

Structural Investigation of the 20S Proteasome and Anesthetic Agents

在线全文

学校读者我要写书评

暂无评论

Structural Investigation of the 20S Proteasome and Anestheti...

Microstructure and mechanical properties of double-side friction stir welded 6082Al ultra-thick plates

作者： y.Morimoto k.Nishio u.Bahudin I.Hisatome Medical School Tottori University

INTRODuCTION:Proteasomes(or muiticatalytic protease complexes) are widely distributed in eukaryotes, ranging from human to *** are involved not only in selective destruction of short-lived regulatory proteins but also in the removal of abnormal,misfolded or improperly assembled proteins generated in cells. There are growing lines of evidence addressing the importance of proteolysis mediated by proteasomes and their partner ubiquitin,which is responsible for many biological processes,including cell cycle,apoptosis,sig-

关键词：

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

Journal of Materials Science & Technology 2020年第6期41卷 105-116页

作者： C.yang J.F.Zhang G.N.Ma l.H.Wu X.M.Zhang G.Z.He P.Xue D.R.Ni B.l.Xiao k.S.Wang Z.y.Ma Shenyang National laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China CRRC Changchun Railway Vehicles Co. Ltd.Changchun 130062China School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an 710055China

In the present work,80 mm thick 6082Al alloy plates were successfully double-side welded by friction stir welding(FSW).The relationship between the microstructures and mechanical properties was built for the double-side FSW butt joint with more attention paid to the local characteristic *** was shown that a phenomenon of microstructural inhomogeneity existed in the nugget zone(NZ)through the thickness *** grain size presented an obvious gradient distribution from the top to the bottom for each single-pass weld,and the microhardness values decreased from both surfaces to the middle of the *** lowest hardness zone(lHZ)exhibited a"hyperbolical"-shaped distribution extending to the middle of the *** tensile properties were obtained in the three sliced specimens of the FSW joint,and the joint coefficient reached about 70%which achieved the same level as the conventional FSW Al alloy *** element modeling proved that the"hyperbolical"-shaped heat affected zone(HAZ)was beneficial to resisting the strain concentration in the middle layer specimen which helped to increase the tensile *** on the analysis of the hardness contour map,tensile property and microstructural evolution of the joints,an Isothermal Softening layer(ISl)model was proposed and established,which may have a helpful guidance for the optimization on the FSW of ultra-thick Al alloy plates.

关键词： ultra-thick aluminum alloy plates Double-side friction stir welding Finite element model Microstructural inhomogeneity Mechanical properties

Salinity Distribution at Canal Istanbul and Its Possible Impacts on the Northern Marmara Sea

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2020年第6期34卷 881-888页

作者： Şehriban SAÇu Tarkan ERDIk OlgayŞEN Istanbul Technical university MaslakIstanbul 34467Turkey

Turkey has announced its plan to construct a new waterway, Canal Istanbul, parallel to the Bosphorus. In this study,the influence of Canal Istanbul on salinity distribution in the northern Marmara Sea is investigated using a previously calibrated 3 D hydrodynamic and salinity model. Moreover, the salinity field of the canal and its propagation are examined based on various meteorological cases. Finally, the flow structure of the canal is determined. It is calculated that at the southern end of the canal, mainly unidirectional flow(from the Black Sea to the Marmara Sea)occurs during 68% of the simulation period. A two-layer flow is seen only 28% of the time with a weak lower layer flow, whereas this value decreases to 4% at the north end of the canal. In the southward direction(to the Marmara Sea), velocities higher than 1.5 m/s are rarely observed along the canal. The average surface salinity difference in the northern Marmara Sea due to the construction of the canal is calculated to be smaller than 0.50 ppt. The salinity difference gradually diminishes as water depth increases and after 25 m(from the surface) almost no difference is observed.

关键词： Canal Istanbul Marmara Sea salinity distribution hydrodynamic modeling

Bulk and local textures of pure magnesium processed by rotary swaging

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2013年第4期1卷 341-345页

作者： W.M.Gan y.D.Huang R.Wang Z.y.Zhong N.Hort k.u.kainer N.Schell H.-G.Brokmeier A.Schreyer Institute of Materials Research Helmhlotz-Zentrum GeesthachtMax-Planck-Str.1D-21502 GeesthachtGermany Institute for Materials Science and Engineering Clausthal University of TechnologyAgricolastrasse 6D-38678 Clausthal-ZellerfeldGermany

Rotary swaging processing on commercial as-cast pure Mg has been carried out. Bulk texture variation with the processing passes was investigated using large gauge volume by neutron diffraction, of which results showed a combination of different components such as {00.2} basal fibre and two weak {10.0} and {11.0} fibres. Asymmetric distribution of the basal fibre around swaging direction was observed and being related to the processing parameters. Texture gradient analysis by synchrotron radiation demonstrates a non-uniform deformation of the RS processed pure Mg from surface to the centre.

关键词： Rotary swaging Pure magnesium Bulk and local textures

Inter-observer variability in histopathological assessment of liver biopsies taken in a pediatric open label therapeutic program for chronic HBV infection treatment

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

World Journal of Gastroenterology 2006年第11期12卷 1713-1717页

作者： Marek Woynarowski Joanna Cielecka-kuszyk Andrzej ka■u■y(n|')ski Aleksandra Omulecka Maria Sobaniec-■otowska Julian Stolarczyk Wojciech Szczepa(n|')ski Department of Gastroenterology Hepatology and Immunology Children's Health Memorial InstituteWarsawPoland Department of Pathology Children's Health Memorial Institute WarsawPoland Department of Pathology Polish Mother Memorial Research Institute ■ód(z|')Poland Department of Pathology Medical university of ■ód(z|') Poland Department of Clinical Pathology Medical university of Bialystok Poland Department of Pathology Medical Academy of Gda(n|')sk Poland Department of Pathology Jagiellonian university Medical College KrakówPoland

AIM： To our knowledge, the inter-observer variability of the liver biopsy findings in HBV-infected children have not been studied as yet. Hence, we aimed to compare different pathologist＇s assessment of grading and staging in liver biopsies obtained from children prior to interferon treatment. METHODS： We collected 920 biopsies from 11 medical centers. The biopsies were independently reviewed by 6 pathologists from academic centers who assessed Batts-ludwig score for grading and staging. Satisfactory agreement among observers was defined as at least 60% of observers having the same opinion. Satisfactory dispersion between maximal and minimal score for the same biopsy specimen was defined as a maximum 1 point. RESulTS： Satisfactory inter-observer agreement for grading was obtained in 51.6% and for staging in 75.7% of biopsies. Satisfactory dispersion for grading scores was observed in 44.5% and for staging in 72.7% of cases. CONCluSION： Our study demonstrates that：（1） pathologists differ in their assessment of grading and staging of liver biopsies; （2） inter-observer variability for staging is lower than that for grading; and （3） regardless of the inter-observer variability of assessments, the majority of children with chronic HBV infection have mild to moderate inflammation and mild to moderate fibrosis.

关键词： Grading Staging Type B Hepatitis Children