检索结果-南通市图书馆

grain refinement mechanism of Mg-3Sn-1Mn-1La alloy during accumulative hot rolling

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第32期91卷 251-261页

作者： z.y.zhao R.g.guan y.F.Shen P.K.Bai School of Materials Science and Engineering North University of ChinaTaiyuan 030051China bEngineering Research Center of Continuous Extrusion Ministry of EducationDalian Jiaotong UniversityDalian 116028China Key Laboratory for Anisotropy and Texture of Materials Northeastern UniversityShenyang 110004China

We elucidate the effect of lanthanum(La) on the grain refinement of Mg-3 Sn-1 Mn alloy during accumulative hot rolling. The lath-shaped Mg_(2) Sn phase in the Mg-3 Sn-1 Mn alloy is firstly broken and spheroidized,and then the size increases and coarsens with the increase of rolling reduction, most of Mg_(2) Sn move from grain boundary to grain and are homogeneously distributed within the matrix. However, the plate-shaped Mg Sn La compound in Mg-3 Sn-1 Mn-1 La gradually becomes fine, spheroidized, and homogeneously distributed. The grain sizes of Mg-3 Sn-1 Mn and Mg-3 Sn-1 Mn-1 La alloys become fine through dynamic recrystallization(DRX), though the grain refinement of Mg-3 Sn-1 Mn-1 La alloy is better compared to the Mg-3 Sn-1 Mn alloy. A large number of uniformly distributed spherical Mg Sn La compounds pin the dislocations, thus increasing the dislocation density. Hence, the driving force for DRX increases and promotes the formation of deformation bands and more twins, providing the sites for DRX nucleation and growth.

关键词： Mg alloy grain refinement Dynamic recrystallization Accumulative hot rolling

Effect of Organosilicon Coating Containing Light Stabilizer on UV Aging Resistance of Bitumen

在线全文

学校读者我要写书评

暂无评论

武汉理工大学学报 2010年第17期32卷 83-88页

作者： HUANg y FENg z g yU J y Key Laboratory of Silicate Materials Science and Engineering of Education Ministry Wuhan University of TechnologyWuhan 430070China

Effects of organosilicon coating with light stabilizer UV326,UV531 and 770 on ultraviolet (UV) aging resistance of bitumen were investigated by testing the viscosity,softening point and the changes of chemical component before and after UV aging. The results show that UV aging resistance of bitumen is improved due to the good weatherability of organosilicon. And the UV aging resistance of bitumen is further enhanced by adding light stabilizer into organosilicon coating due to the good UV absorption of light stabilizers. Bitumen coated with organosilicon coating containing UV326 exhibits better UV aging resistance in comparison with bitumen coated with organosilicon containing UV531 or 770.

关键词： bitumen light stabilizer organosilicon coating UV aging

Correlation between depassivation and repassivation processes determined by single particle impingement:Its crucial role in the phenomenon of critical flow velocity for erosion-corrosion

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第30期89卷 158-166页

作者： L.L.Li z.B.Wang S.y.He y.g.zheng CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China department of Physics Southern University of Science and TechnologyGuangdong 518055China

The correlation between depassivation and repassivation processes,which is significant in erosioncorrosion,was quantitatively investigated by single particle impingement tests at various flow velocities and impact *** results show that both repassivation and depassivation processes are associated with the kinetic energy of solid particle,and demonstrate that the repassivation is retarded by *** phenomenon probably results from the depassivation-induced microstructure *** this basis,the dependence of critical flow velocity(CFV)for erosion-corrosion on the solid particle concentration and diameter is further theoretically predicted and experimentally ***,the crucial role of depassivation-repassivation in CFV phenomenon is further highlighted.

关键词： Erosion-corrosion Stainless steel depassivation-repassivation Single particle impact Passive film

Bell Polynomial Approach for the Solutions of Fredholm Integro- Differential Equations with Variable Coefficients

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2020年第6期123卷 973-993页

作者： gökçe yıldız gültekin Tınaztepe Mehmet Sezer department of Mathematics Faculty of ScienceManisa Celal Bayar UniversityManisaTurkey Vocational School of Technical Sciences Akdeniz UniversityAntalyaTurkey

In this article,we approximate the solution of high order linear Fredholm integro-differential equations with a variable coefficient under the initial-boundary conditions by Bell *** collocation points and treating the solution as a linear combination of Bell polynomials,the problem is reduced to linear system of equations whose unknown variables are Bell *** solution to this algebraic system determines the approximate *** estimation of approximate solution is *** examples are provided to illustrate the performance of the *** numerical results are compared with the collocation method based on Legendre polynomials and the other two methods based on Taylor *** is observed that the method is better than Legendre collocation method and as accurate as the methods involving Taylor polynomials.

关键词： Bell polynomials collocation points matrix method Fredholm integrodifferential equations.

Enhanced pitting corrosion resistance of a zr-based metallic glass by ultraviolet light irradiation

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 Iron and Steel Research International 2023年第8期30卷 1642-1649页

作者： z.Chen D.P.Wang S.Wang y.X.geng y.X.guo y.C.Wu z.g.Liu y.y.zhang y.X.Wang School of Materials Science and Engineering Jiangsu University of Science and Technology.Zhenjiang 212003JiangsuChina School of Mechanical Engineering Jiangsu University of Science and TechnologyZhenjiang 212003JiangsuChina

The influence of ultraviolet light irradiation on the pitting corrosion performance of a zr_(2)Ni metallic glass was examined using electrochemical methods and immersion test in 0.05 mol/L NaCl *** the results of potentiostatic polarization,the pitting potential of the ultraviolet light-irradiated sample shifted positively with a value of~300 mV,revealing the enhanced pitting corrosion resistance of the *** corrosion morphology after the immersion test also demonstrated lower degree of corrosion damage and improved pitting resistance of the sample with ultraviolet light irradiation.X-ray photoelectron spectroscopy analysis revealed more zirconium enrichment in the passive film and no chloride ions adsorption for the samples with ultraviolet irradiation,accounting for the suppression of the pit generation and *** findings indicate that ultraviolet light irradiation improves the pitting corrosion resistance of the zr-based metallic glasses,which are promising structural materials to be used in corrosion environments with high ultraviolet irradiation.

关键词： Metallic glass Pitting-Corrosion Ultraviolet light irradiation Passive film

Associations of polygenic risk scores with risks of stroke and its subtypes in Chinese

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

Stroke & Vascular Neurology 2024年第4期9卷 399-406,I0044-I0065页

作者： Songchun yang zhijia Sun Dong Sun Canqing yu yu guo Dianjianyi Sun yuanjie Pang Pei Pei Ling yang Iona y Millwood Robin g Walters yiping Chen Huaidong Du yan Lu Sushila Burgess Daniel Avery Robert Clarke Junshi Chen zhengming Chen Liming Li Jun Lv On behalf of the China Kadoorie Biobank Collaborative group department of Epidemiology&Biostatistics School of Public HealthPeking UniversityBeijingChina department of dermatology Xiangya HospitalCentral South UniversityChangshaHunanChina Peking University Center for Public Health and Epidemic Preparedness&Response BeijingChina Key Laboratory of Epidemiology of Major Diseases(Peking University) Ministry of EducationBeijingChina Fuwai Hospital Chinese Academy of Medical Sciences BeijingChina Medical Research Council Population Health Research Unit at the University of Oxford OxfordUK Clinical Trial Service Unit&Epidemiological Studies Unit(CTSU) Nuffield Department of Population HealthUniversity of OxfordOxfordUK NCDs Prevention and Control department Suzhou CDCSuzhouJiangsuChina China National Center for Food Safety Risk Assessment BeijingChina State Key Laboratory of Vascular Homeostasis and Remodeling Peking UniversityBeijingChina 不详

Background and purpose Previous studies,mostly focusing on the European population,have reported polygenic risk scores(PRSs)might achieve risk stratification of *** aimed to examine the association strengths of PRSs with risks of stroke and its subtypes in the Chinese *** Participants with genome-wide genotypic data in China Kadoorie Biobank were split into a potential training set(n=22191)and a population-based testing set(n=72150).Four previously developed PRSs were included,and new PRSs for stroke and its subtypes were *** PRSs showing the strongest association with risks of stroke or its subtypes in the training set were further evaluated in the testing *** proportional hazards regression models were used to estimate the association strengths of different PRSs with risks of stroke and its subtypes(ischaemic stroke(IS),intracerebral haemorrhage(ICH)and subarachnoid haemorrhage(SAH)).Results In the testing set,during 872919 person-years of follow-up,8514 incident stroke events were *** PRSs of any stroke(AS)and IS were both positively associated with risks of AS,IS and ICH(pg HR_(SD) of PRS_(IS) was 1.08(95%CI 1.06 to 1.11),1.08(95%CI 1.06 to 1.11)and 1.09(95%CI 1.03 to 1.15).PRS_(ICH) was positively associated with the risk of ICH(HR_(SD)=1.07,95%CI 1.01 to 1.14).PRSS_(AH) was not associated with risks of stroke and its *** addition of current PRSs offered little to no improvement in stroke risk prediction and risk *** In this Chinese population,the association strengths of current PRSs with risks of stroke and its subtypes were moderate,suggesting a limited value for improving risk prediction over traditional risk factors in the context of current genome-wide association study under-representing the East Asia

关键词： testing prediction increment

Effect of y Addition on Microstructure and Mechanical Properties of Friction Stir Welded zK60 Alloy

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 2009年第3期25卷 351-355页

作者： g.M. Xie z.y. Ma L. geng School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

6 mm thick zK60 and zK60-y alloy plates were successfully friction stir welded （FSW） at a tool rotation rate of 1200 r/min and a traverse speed of 100 mm/min. FSW resulted in the dissolution of Mgzn2 particles in the zK60 and the breakup and dispersion of W-phase （Mg3zn3y2） particles in the zK60-y alloy, thereby leading; to a decrease in the hardness of the nugget zone （Nz） for the zK60 alloy and an increase in the hardness of the Nz for the zK60-y alloy, respectively. While two FSW joints exhibited similar joint efficiency （87%-89% of ultimate tensile strengths of the parent materials）, the yield strength of the FSW zK60-y joint was substantially higher than that of the FSW zK60 joint. The fracture occurred in the Nz and the heat affected zone for the zK60 and zK60-y joints, respectively, which were consistent with the lowest hardness distribution of the welded joints.

关键词： Friction stir welding Magnesium Microstructure Mechanical properties

PARAMAgNETIC MEISSNER EFFECTS IN MELT-TEXTURED y_(0.99)Nd_(0.01)Ba_2Cu_3O_(7-y)SUPERCONDUCTOR

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2002年第3期15卷 295-298页

作者： Xing y.T. Wang y.z. Qiao g.W. Inst. of Metal Res. Chinese Acad. of Sci. Shenyang 110016 China

The paramagnetic Meissner effect (PME) was observed on the field-cooled M-T curves of melt-textured y0.99Nd0.01Ba2Cu3O7-y in applied magnetic fields from 1kOe to 40kOe. In the magnetic field below 1kOe, the sample undergoes the typical transition from the normal state to the superconducting state when it was cooled down. The applied magnetic fields in which the PME occurs, are very high compared with the fields reported in literatures. We propose that the occurrence of the PME may be due to a phase transition of flux vortices in the superconductors.

关键词： yBCO superconductor paramagnetic Meissner effect (PME)

Ab initio valence-space in-medium similarity renormalization group calculations for neutron-rich P,Cl,and K isotopes

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2024年第7期48卷 181-190页

作者：谢萌冉沈留媛李健国李红蕙袁琪左维 Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China

Neutron-rich P,Cl,and K isotopes,particularly those with neutron numbers of approximately N=28,have attracted extensive experimental and theoretical *** utilize the ab initio valence-space in-medium similarity renormalization group approach,based on chiral nucleon-nucleon and three-nucleon forces,to investigate the exotic properties of these *** calculations of the low-lying spectra are performed.A key finding is the level inversion between 3/2_(1)^(+)and 1/2_(1)^(+)states in odd-A isotopes,attributed to the inversion ofπ0xod_(3/2) andπls_(1/2) single-particle *** ab initio calculations,which incorporate the three-nucleon forces,correlate closely with existing experimental *** calculations of effective proton single-particle energies provide deeper insights into the shell evolution for z=14 and 16 *** results indicate that the three-body force plays important roles in the shell evolution for z=14 and 16 sub-shells with neutron numbers ranging from 20 to ***,systematic ab initio calculations are conducted for the low-lying spectra of odd-odd *** results correspond with experimental data and provide new insights for future research into these isotopes up to and beyond the drip line.

关键词： ab initio calculations shell evolution low-lying spectra