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Enhancement of Sinter Densification of SrO-BaO-Nb_2O_5-SiO_2 Tungsten-Bronze Glass-Ceramics by Doping with P_2O_5

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Journal of Materials Science & Technology 2013年第8期29卷 731-736页

作者： J.C.chen y.Zhang Shenyang Research and Development Centre for Advanced Materials Institute of Metal ResearchChinese Academy of Sciences State Key Laboratory of New Ceramics and Fine Processing Institute of Nuclear and New Energy TechnologyTsinghua University

Densification behaviors of SrO-BaO-Nb2O5-SiO2 based glass-ceramics prepared by conventional sintering were investigated with an emphasis on the influence of P2O5 content. Although P2O5 dopant did not modify the surface crystallization mechanism, it resulted in a decrease of the glass transition temperature, which facilitates the viscous glass flow necessary for sintering. However, premature crystallization of （Sr, Ba）Nb2O6 induced by addition of excess amount of P2O5 essentially retarded sintering due to the formation of closed pores in the matrix. The SrO-BaO-Nb2O5-SiO2 glass with 1.0 mol% P2O5 （SBN-1P） showed the best sinter densification, which was accomplished at about 850 ℃.

关键词： Sintering densification DieLectric properties Glass-ceramic

Alloy solidification: Assessment and improvement of an easy-to-apply model

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Journal of Materials Science & Technology 2022年第35期130卷 1-11页

作者： H.Liu y.Liu S.L.Lu y.Zhang H.chen y.chen M.Qian School of Materials Science and Engineering Southwest Jiaotong UniversityChengdu 610031China Centre for Additive Manufacturing School of EngineeringRMIT UniversityMelbourneVIC 3000Australia School of Materials Science and Engineering Sichuan UniversityChengdu 610065China

It has been a central task of solidification research to predict solute microsegregation. Apart from the Lever rule and the Scheil-Gulliver equation, which concern two extreme cases, a long list of microsegregation models has been proposed. However, the use of these models often requires essential experimental input information, e.g., the secondary dendrite arm spacing(λ), cooling rate( ˙T) or actual solidification range(△T). This requirement disables these models for alloy solidification with no measured values for λ,˙T and △T. Furthermore, not all of these required experimental data are easily obtainable. It is therefore highly desirable to have an easy-to-apply predictive model that is independent of experimental input,akin to the Lever rule or Scheil-Gulliver model. Gong, chen, and co-workers have recently proposed such a model, referred to as the Gong-chen model, by averaging the solid fractions(f_(s)) of the Lever rule and Scheil-Gulliver model as the actual solid fraction. We provide a systematic assessment of this model versus established solidification microsegregation models and address a latent deficiency of the model, i.e.,it allows the Lever rule solid fraction fsto be greater than one(f_(s)> 1). It is shown that the Gong-chen model can serve as a generic model for alloy solidification until fsreaches about 0.9, beyond which(f_(s)> 0.9) its applicability is dictated by both the equilibrium solute partition coefcient(k) and the solute diffusion coefcient in the solid(Ds), which has been tabulated in detail.

关键词： Solidification Microsegregation Solute Back diffusion Eutectic formation

Interaction between adjacent left-lateral strike-slip faults and thrust faults: the 1976 Songpan earthquake sequence

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Chinese Science Bulletin 2008年第16期53卷 2520-2526页

作者： y. John chen Department of Geophysics School of Earth and Space Sciences Peking University

Based on the published focal mechanisms we have built the fault model of the main shocks of the 1976 Songpan earthquake sequence and calculated the coseismic Coulomb stress changes in the region. The results show that most of the aftershocks had occurred in the region where the Coulomb stresses had been increased, indicating a triggering relationship between the main shocks and the aftershocks. We also show that the first main shock (Ms = 7.2), which is a left-lateral slip event, had increased the Coulomb stresses by 5×105 Pa at the second main shock (a thrust event with Ms = 6.7). Therefore, we conclude that the first main shock had triggered the second main shock. The third main shock is also a left-lateral event, however, the triggering relationship between the third main shock and the previous two events is less obvious. General model calculations show that there is a good triggering relation- ship between adjacent left-lateral slip fault and thrust fault, but triggering between parallel slip faults is rather weak.

关键词：松潘大地震序列断层地震波

Differences in the immunogenicity of engineered circular RNAs

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Journal of Molecular Cell Biology 2023年第1期15卷 1-6页

作者： Justin Tai y.Grace chen Department of Immunobiology Yale University School of MedicineNew HavenCTUSA

Circular RNAs(circRNAs)are single-stranded RNAs that are covalently closed and lack free *** current understanding of the functions and regulation of circRNAs in immune systems is still in the nascent stages,but several groups have recently investigated the immunogenicity of engineered ***,which factors determine engineered circRNA immunogenicity still remains ***,we review and compare these investigations on engineered circRNA *** discuss the possible factors that may alter the immunogenic potential of a circRNA,such as its generation,purification,primary sequence,secondary structure,and RNA *** also suggest approaches for designing a circRNA with immunostimulatory or immune-evasive properties and recommend future areas for the field to *** the factors underlying engineered circRNA immunogenicity is an important step towards understanding endogenous circRNA immunity and increasing the therapeutic potential of circRNAs.

关键词： immunity immunogenicity endogenous

Analysis of Contact Melting Driven by Surface Heat Flux Around a Cylinder

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Journal of Thermal Science 2008年第1期17卷 64-68页

作者： y.S.Zhao W.Z.chen F.R.Sun Z.y.chen Faculty of Thermal Engineering College of Power and ShippingNaval University of EngineeringWuhan 430033China Faculty of Thermal Engineering College of Power and ShippingNaval University of EngineeringWuhan 430033China Professor

The contact melting of phase change material around a moving horizontal cylindrical heat source, which descended under its own weight, is investigated in this article. A melting model under constant surface heat flux is established. The analytical results for thickness and pressure distributions inside melt layer and steady melting velocity are obtained by using contact melting theory. The melting law is discussed, and compared with that of contact melting driven by temperature difference. It is found that quasi-steady melting velocity is determined by heat flux of heat source, and the variation of heat source density has less effect on melting velocity.

关键词： Contact melting horizontal cylinder phase change phenomena

CAPILLARy　ELECTROPHORESIS　DETERMINATION　OF　INOSINE　IN　SOMEDRUG　FORMULAE　USING　HyPOXANTHINE　AS　INTERNAL　STANDARD

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Chinese Chemical Letters 1995年第8期6卷 701-704页

作者： chen, y yuan, ZB Acad Sinica USTC Grad Sch Beijing 100039 Peoples R China

A new rapid and accurate method for determining inosine by capillary zone electrophoresis(CZE) is presented. The electrophoresis separation was performed at 24℃ in a fused-silica capillary(51.2cm×50 μmi.d., 38.5cm to UV detector)using 20mmol/L borax-20mmol/L H3PO4(pH 8.5) as the background electrolyte at 24KV applied voltage. Inosine samples were led into the capillary electrokinetically at 10KV for 15 seconds. In the range of 20μg/mL to 300μg/mL, inosine can be quantitatively determined with a deduction limit of 2.1μg/mL and a RSD of 2.92%. Hypoxanthine was used as the internal standard.

关键词：

NUMERICAL SIMULATION OF INDUCTION SKULL MELTING PROCESS FOR TITANIUM-ALUMINIUM BASE ALLOy

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Acta Metallurgica Sinica(English Letters) 2004年第6期17卷 928-933页

作者： Z.y.chen L.J.Xu F.T.Kong Q.Shu y.y.chen SchoolofMaterialsScienceandEngineering HarbinInstituteofTechnologyHarbin150001China

The mathematics model for temperature field of water-cooling copper crucible induction skull melting process was established. The program for simulating temperature field of melting process was developed with finite element method. The temperature field of the melting process for Ti-47Al-2Cr-2Nb alloy was calculated. During melting period, the temperature is raised gradually along radius augmentation direction. The elements of the charge near the crucible wall are molten first. The center elements of the charge are molten last. The melting time of the center element is just that of all the charge melting. The melting time of Ti-47Al-2Cr-2Nb alloy is 15min. In which, the charge was heated by low power 80kW for 9min and by high power 300kW for 6min. When melting Ti-47Al-2Cr-2Nb alloy, the loading power is nearly direct proportion to melt temperature. Increasing loading power may raise melt temperature. The best melting power of Ti-47Al-2Cr-2Nb alloy is 305-310kW. This is identical with the melting test and has guidance sense to the melting process of actual titanium alloy.

关键词： TiAl base alloy melting numerical simulation

Quantum chemical studies on antimalarial of artemisinin (qinghaosu) derivatives

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Chinese Journal of Chemistry 1995年第2期13卷 131-140页

作者： JIANG, HL chen, KX TANG, y chen, JZ JI, Ry CHINESE ACAD SCI SHANGHAI INST MAT MEDSHANGHAI 200031PEOPLES R CHINA

In this paper theoretical studies were performed on artemisinin (qinghaosu) derivatives with semiempirical quantum chemical methods AM1 and PM3. The antimalarial activity -logC has an obvious correlation with the net charge of C(16) and bond orders of bonds O(1)-C(10), O(2)-C(6), O(1)-O(2) and O(5)-C(16). According to the calculation results, we derived structure-activity relationship, presented the probable pharmacophore of qinghaosu derivatives and the interaction fashion between the drugs and the plasmodium receptor.

关键词： ARTEMISININ (QINGHAOSU) ANTIMALARIAL QUANTUM CHEMISTRy PHARMACOPHORE

Cell therapy for macular degeneration—first phase Ⅰ/Ⅱ pluripotent stem cell-based clinical trial shows promise

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Science China(Life Sciences) 2015年第1期58卷 119-120页

作者： chen ZhiGuo ZHANG y.Alex Cell Therapy Center Xuanwu HospitalCapital Medical University and Key Laboratory of NeurodegenerationMinistry of Education Center of Neural Injury and Repair Beijing Institute for Brain Disorders

Embryonic stem（ES）cells,a type of pluripotent stem cells（PSCs）that are derived from the inner cell mass of blastocysts,have been discovered for more than three decades[1].Given the almost infinite self-renewal capacity and the potential to differentiate into any specific cell type in an individual,ES cells and PSCs have brought hope for the treatment of many unmet ***,the advantages of PSCs-the highly proliferative and plastic capacities,also give rise to concerns regarding the development of tumors.

关键词：多能干细胞系细胞治疗临床试验自我更新能力变性黄斑显示 PSCs