TRANSIENT RESPONSE OF A BI-LAYERED MULTIFERROIC COMPOSITE PLATE

In this paper,a three-dimensional finite-element formulation for the multiferroic composite is developed and implemented into the commercial software ABAQUS for its transient analysis.First,a special three-dimensional eight-node solid element is designed to handle the multiferroic composite made of elastic,piezoelectric,and piezomagnetic materials.Second,a userdefined subroutine for this newly developed element is implemented into ABAQUS.Finally,the transient responses of a bi-layered multiferroic composite are calculated by using the direct time integration method.Two typical magnetic potential signals,Gauss and Ricker pulses,are applied to the composite with various time durations of excitation.The induced electric field shows that the transient response can be substantially influenced by the input signal,which could be tuned for the strongest electric output.     

Cu掺杂TiO_2作为SERS基底的研究

本文采用溶胶-水热法制备了TiO2及Cu掺杂的TiO2纳米粒子作为表面增强拉曼光谱(SERS)活性基底,观察到当4-巯基苯甲酸吸附在3%Cu掺杂的TiO2表面上时,其SERS信号得到了最大程度的增强.Cu离子掺杂进TiO2晶格时会使TiO2表面的缺陷浓度(表面态)得到增加,一定量的缺陷浓度对TiO2-to-Molecule的电荷转移机理起到促进作用,进一步证明了化学增强机理在SERS现象的贡献.     

Design,synthesis and evaluation of spermine-based pH-sensitive amphiphilic gene delivery systems: Multifunctional non-viral gene carriers

Design and development of efficient non-viral gene delivery systems is critical to overcome various barriers for effective intracellular gene delivery.Eight new spermine-based protonatable surfactants were designed,synthesized and evaluated as non-viral pH-sensitive gene carriers.These carriers formed stable complexes with plasmid DNA at an N/P ratio as low as 2.The sizes of the carrier/pDNA nanoparticles (N/P = 12) were in the range of 90–130 nm,smaller than that of Lipofectamine2000/pDNA nanoparticles.The...     

Combined fit to BABAR and Belle Data on e^＋e^- →φπ^＋π^- and φf0（980）

A combined fit is performed to the BABAR and Belle measurements of the e^＋e^- →φπ^＋π^- and φf0（980） cross sections for center-of-mass energy between threshold and 3.0 GeV. The resonance parameters of the φ（1680） and Y（2175） are determined. The mass is （1681-12^＋10） MeV/c^2 and the width is （221-24^＋34） MeV/c^2 for the φ（1680）, and the mass is （2117-49^＋59） MeV/c^2 and the width is （164-80^＋69） MeV/c^2 for the Y（2175）. This information will shed light on the understanding of the nature of the excited φ and Y states observed in e＋e- annihilation.     

Design and study of a high-current 5-cell superconducting rf cavity

The Advanced Photon Source （APS） at Argonne National Laboratory is considering the development of a superconducting linac-based fourth-generation hard X-ray source to meet future scientific needs of the hard X-ray user community. This work specifically focuses on the design of an optimized 5-cell superconducting radio-frequency structure well suited for a high-energy, high-beam-current energy recovery linac. The cavity design parameters are based on the APS storage ring nominal 7 GeV and 100 mA beam operation. A high-current 5-cell cw superconducting cavity operating at 1.4 GHz has been designed. In order to achieve a high current, the accelerating cavity shape has been optimized and large end-cell beam pipes have been adopted. The beam break-up threshold of the cavity has been estimated using the code TDBBU, which predicts a high threshold beam current for a 7 GeV energy recovery linac model. A copper prototype cavity has been fabricated that uses half-cell modules, initially assembled by clamping the cells together.     

Carbon dioxide conversion to valuable chemical products over composite catalytic systems

This paper reports an experimental study on catalytic conversion of carbon dioxide to methanol,ethanol and acetic acid.Catalysts having different catalytic functions were synthesized and combined in different ways to enhance the selectivity to desired products.The combined catalyst system possessed the following functions:methanol synthesis,Fischer-Tropsch synthesis,water-gas-shift and hydrogenation.Results showed that the methods of integrating these catalytic functions played an important role in achieving the desired product selectivity.We speculate that if methanol synthesis sites were located adjacent to the C-C chain growth sites,the formation rate of C₂ oxygenates would be enhanced.The advantage of using a high temperature methanol catalyst PdZnAl in the combined catalyst system was demonstrated.In the presence of PdZnAl catalyst,the combined catalyst system was stable at 380°C.It was observed that,at high temperature,kinetics favored oxygenate formation.The results implied that the process can be intensified by operating at high temperature using Pd-based methanol synthesis catalyst.Steam reforming of the byproduct organics was demonstrated as a means to provide supplemental hydrogen.Preliminary process design,simulation,and economic analysis of the proposed CO₂ conversion process were carried out.Economic analysis indicates how ethanol production cost was affected by the price of CO₂ and hydrogen.     

镜像配基筛选:克服“酶屏障”的多肽、寡核苷酸药物研发技术

生物体内存在的酶屏障是功能性多肽和寡核苷酸成药的重要瓶颈.以镜像噬菌体展示技术(mirror-image phage display)和镜像适配体筛选技术(Spiegelmer technology)为代表的镜像配基筛选技术能有效地克服这一屏障,获得对靶点具有特异识别能力且在生理条件下高度稳定的D型多肽和L型寡核苷酸配基,有望成为多肽或寡核苷酸类特异性药物研发的有利工具.本文主要综述镜像配基筛选技术的原理及其在药学领域的研究进展.     

Design of polarization-maintaining retro-reflector for folded-path applications

A design of polarization-maintaining retro-reflectors(PMRRs) for folded-path applications is proposed and analyzed.The prism-based scheme enables the output light,which is parallel to the input,to have an identical state of polarization.The principle of the design is theoretically verified,and the related error is analyzed due to possible manufacturing imperfection.The maximum spatial angle error is ±2.75°.The effect on the extinction ratio and insertion loss is also discussed,which further proves the design’s feasibility in practical applications.     

非均质材料力学研究进展: 热点、焦点和生长点 ————- ICHMM2008的观察和启迪

本文结合第二届国际非均质材料力学会议 (ICHMM2008,黄山)专题讨论会和部分特邀报告的情况, 以及2011年5月22$\sim$26日在上海崇明岛举行的ICHMM2011国际会议的内容, 对该领域的研究进展及其热点、焦点和生长点进行了综合性的评述. 重点讨论了多物理场与多尺度模拟、材料结构与力学行为从原子到连续介质的分析、随机微结构演化与退化、真实材料微结构的模拟、生物材料力学与仿生设计、在位实验和模型验证、功能梯度材料结构力学、微纳米功能器件开发等前沿性课题. 其中特别用较多的篇幅讨论了多物理场与多尺度模拟的背景、目标、必要性、现有方法的优缺点、障碍、应用例子与其他前沿研究领域的联系及其发展态势, 并阐述其研究焦点与值得注意的进展.      

EFFECT OF COMPOSITION AND PROCESSING CONDITION ON MICROSTRUCTURAL PROPERTIES AND DURABILITY OF FLUOROPOLYMER/ACRYLIC BLENDS

Fluoropolymer blends have been widely used as binders for exterior coatings because of their excellent resistance to ultra-violet (UV) radiation as well as to many corrosive chemical agents.It is known that the fluorinated component usually has a lower glass transition temperature and easily crystallizes in the final structure depending upon the blend composition and sample annealing condition.We investigated the effect of blend composition and annealing process (slow and fast cooling) on the surface mor...