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

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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

SyNTHESIS AND MICROSTRUCTURE OF SUPERHARD TiN/SiN_x MULTILAyER THIN FILMS

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Acta Metallurgica Sinica(English Letters) 2005年第3期18卷 242-248页

作者： Z.F.Zhou y.g.Shen y.W.Mai K.y.Li AdvancedCoatingsAppliedResearchLaboratory（ACARL） DepartmentofManufacturingEngineeringandEngineeringManagementCityUniversityofHongKongKowloonHongKongChina CentreforAdvancedMaterialsTechnology（CAMT） SchoolofAerospaceMechanicalandElectronicEngineeringUniversityofSydneySydneyNSW2006Australia

Multilayer thin films of TiN/SiNx have been deposited onto heated Si 100 substra tes (200℃) by reactive dc-magnetron sputtering from Ti and Si targets in an Ar- N2 gas mixture. The rotation speed of the substrate holder was varied from 1 to 20rpm, while target currents were held constant, to produce bilayer periods vary ing from approximately 22 to 0.6nm. These multilayer films were characterized by atomic force microscopy (AFM), cross-sectional transmission electron microscopy (TEM), scanning electron microscopy (SEM), and microhardness measurements. TEM and SEM studies showed elimination of columnar structure in TiN, owing to the in corporation of amorphous SiNx layers. The crystallinity of TiN and amorphous nat ure of SiNx were confirmed by high resolution TEM. An optimum rotation speed was observed, at which hardness was a maximum. The resulting bilayer period was fou nd to be approximately 1.6nm, which resulted in a significant improvement in mic rohardness (~57gPa). The rms surface roughness for this film was less than 1.5nm .

关键词： multilayers hardness supermodulu s stress TiN/SiNx

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

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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

A Modified Analytic Function Space Feynman Integral of Functionals on Function Space

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Chinese Annals of Mathematics,Series B 2020年第1期41卷 61-76页

作者： SeungJun CHANg HyunSoo chung Department of Mathematics Dankook UniversityCheonan 330-714Korea

In this paper, the authors introduce a class of functionals. This class forms a Banach algebra for the special cases. The main purpose of this paper is to investigate some properties of the modified analytic function space Feynman integral of functionals in the class. Those properties contain various results and formulas which were not obtained in previous papers. Also, the authors establish some relationships involving the first variation via the translation theorem on function space. In particular, the authors establish the Fubini theorem for the modified analytic function space Feynman integral which was not obtained in previous researches yet.

关键词： generalized Brownian motion process Modified analytic Feynman integral First variation Cameron-Storvick type theorem Fubini theorem

Alkali control of high-grade metamorphism and granitization

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geoscience Frontiers 2014年第5期5卷 711-727页

作者： Oleg g.Safonov Leonid y.Aranovich Institute of Experimental Mineralogy RAS ChernogolovkaMoscow RegionRussia Department of Petrology Moscow State UniversityMoscowRussia Department of geology.University of Johannesburg Johannesburg.South Africa Institute of geology of Ore Deposits PetrographyMineralogy and Geochemistry

We review petrologic observations of reaction textures from high-grade rocks that suggest the passage of fluids with variable alkali activities. Development of these reaction textures is accompanied by regular compositional variations in plagioclase, pyroxenes, biotite, amphibole and garnet. The textures are interpreted in terms of exchange and net-transfer reactions controlled by the K and Na activities in the fluids. On the regional scale, these reactions operate in granitized, charnockitized, syenitized etc. shear zones within high-grade complexes. Thermodynamic calculations in simple chemical systems show that changes in mineral assemblages, including the transition from the hydrous to the anhydrous ones, may occur at constant pressure and temperature due only to variations in the H2O and the alkali activities. A simple procedure for estimating the activity of the two major alkali oxides, K2O and Na2O, is imple- mented in the TWQ software. Examples of calculations are presented for well-documented dehydration zones from South Africa, southern India, and Sri Lanka. The calculations have revealed two end-member regimes of alkalis during specific metamorphic processes： rock buffered, which is characteristic for the precursor rocks containing two feldspars, and fluid-buffered for the precursor rocks without K-feldspar. The observed reaction textures and the results of thermodynamic modeling are compared with the results of available experimental studies on the interaction of the alkali chloride and carbonate-bearing fluids with metamorphic rocks at mid-crustal conditions. The experiments show the complex effect of alkali activities in the fluid phase on the mineral assemblages. Both thermodynamic calculations and experiments closely reproduce paragenetic relations theoretically predicted by D.S. Korzhinskii in the 1940s.

关键词： High-grade metamorphismAlkali activityFluidsReaction texturesFluid-mineral reactionsThermodynamic modeling

SyNTHESIS OF NEW HIgH MOLECULAR WEIgHT AND REACTIVE LADDERLIKE POLySILSESQUIOXANES

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Chinese Journal of Polymer Science 2000年第5期18卷 459-463页

作者： Neal Tai-sheng chung Institute of Materials Research and Engineering Singapore 117602 Singapore

Ladderlike polychloropropylsilsesquioxane (CP-T) was first synthesized by 'stepwise coupling polymerization'. The molecular weight of CP-T is as high as 1.7 x 10(5). It is a tough, elastic reactive ladderlike polymer and has good heat-resistant and adhesive properties. CP-T can further react with many nucleophilic reagents to generate new ladderlike reactive polysilsesquioxanes, which can be used as potential precursors in the synthesis of functional ladderlike polymers.

关键词： stepwise coupling polymerization reactive ladderlike polymer nucleophilic substitution

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Phase change memory

Science China(Information Sciences) 2011年第5期54卷 1061-1072页

作者： LAM chung IBM Research T.J. Watson Research Center Yorktown Heights New York 10598 USA

Phase change memory (PCM) is a non-volatile solid-state memory technology based on the large resistivity contrast between the amorphous and crystalline states in phase change materials. We present the physics behind this large resistivity contrast and describe how it is being exploited to create high density PCM. We address the challenges facing this technology, including the design of PCM cells, fabrication, device variability, thermal cross-talk and write disturb. We discuss the scalability, assess the performance, and examine the reliability of PCM including data retention, multi-bit storage and endurance.

关键词： solid state memory non-volatile DRAM flash phase change resistive memory data retention write endurance solid-state drive computer memory

Self-adhesive pads in defi brillation or cardioversion: risks due to unfamiliarity and recommendations

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World Journal of Emergency Medicine 2024年第1期15卷 64-66页

作者： Hansol chung Department of Emergency Medicine Yeungnam University College of MedicineDaegu 42415Republic of Korea

During cardiopulmonary resuscitation(CPR),defibrillation,or cardioversion,the use of self-adhesive pads instead of conventional paddles has gradually become *** particular,it was recommended during the COVID-19 pandemic,as it allows defibrillation or cardioversion to be performed without close contact between the rescuer and patient.[1,2]Self-adhesive pads can minimize the downtime of chest compressions before and after defibrillation and protect the patient from electric arc formation,skin burns,and fi *** the pads are attached,electrocardiographic rhythm analysis,defibrillation,synchronous cardioversion,and cardiovascular support are all *** paddles,self-adhesive pads can save time because the application of conductive jelly,repeated positioning,and application of 10-12 kg of pressure on the chest are not *** European Resuscitation Council(ERC)guidelines 2021 state that the use of self-adhesive pads is recommended in advanced cardiovascular life support(ACLS).[3]Nevertheless,some medical staff still tend to prefer the use of conventional paddles instead of self-adhesive pads in hospitals.

关键词： attached cardio conductive

Dissociative Chemisorption of an H2（v,j） Molecule on Rigid Ni （100） Surface： Dependence on Surface Topologies and Initial Rovibrational States of the Molecules

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Chinese Physics Letters 2005年第2期22卷 420-423页

作者： MeryemEvecen MustafaBǒyǚkata MehmetCivi ZiyaB.gǚvenc DepartmentofPhysics GaziUniversity06500AnkaraTurkey DepartmentofPhysics ErciyesUniversity66100YozgatTurkey DepartmentofElectronicandCommunicationEngineering CankayaUniversity06530AnkaraTurkey

The H2(v,j)+Ni(100) collision system has been studied to understand the effects of the surface sites and initial rovibrational states of the molecule on molecule-surface interactions, by a quasiclassical molecular dynamic simulation method. Dissociative adsorption of an H2 molecule on the rigid Ni(100) surface is investigated at topologically different three sites of the surface. Interaction between the molecule and Ni surface was described by a London–Eyring–Polani–Sato (LEPS) potential. Dissociative chemisorption probabilities of the H2(v,j) molecule on various sites of the surface are presented as a function of the translation energies between 0.001–1.0eV. The probabilities obtained at each collision site have unique behaviour. At lower collision energies, indirect processes enhance the reactivity, effects of the rotational excitations and impact sites on the reactivity are more pronounced. The results are compared with the available studies. The physical mechanisms underlying the results and quantum effects are discussed.

关键词：氢气分子游离化学吸收镍表面拓扑转振状态