Improved method for loss measurements in planar waveguides

A method employing an isosceles prism and a right-angle one is developed for loss measurement in planar waveguides. During the measuring process, the isosceles prism is fixed and the right-angle prism fixed on the waveguide slides by following the waveguide. Only by adjusting the gap thickness we can realize the loss measurement in planar waveguides. The method is demonstrated with an Ag/Na ion-exchanged waveguide fabricated on BK7 glass from AgNO₃ melt diluted with NaNO₃ (mass ratio 1:9), with the condition of 4 h and . The experimental results show that the method has the advantages on convenient operation, accurate results and no required end polishing.     

纳米载体负载声敏剂的研究进展和挑战

声动力治疗是将低频超声与声敏剂相结合的非侵入性肿瘤治疗方法,由于其副作用小、治疗深度深等优点,受到科学家们的重视。有机声敏剂作为初代声敏剂已经被研究多年,但是其水溶性差、无法在肿瘤部位大量聚集等缺陷阻碍了其声动力应用。快速发展的纳米技术为许多问题的解决提供了新的思路,尤其利用纳米载体负载声敏剂,可以解决有机声敏剂水溶性差、容易被提前释放等问题,实现药物靶向作用,为声动力治疗与其他疗法结合提供平台,进一步发挥声动力治疗疗效。因此,该文总结了纳米载体负载有机声敏剂用于声动力治疗的相关研究,着重介绍纳米载体在声动力治疗中的研究进展及相关机理,指出现存问题,最终希望可以总结出用于声动力治疗的纳米载体的共性,为今后研究提供帮助。     

New Sixth-Order Compact Schemes for Poisson/Helmholtz Equations

Some new sixth-order compact finite difference schemes for Poisson/Helmholtz equations on rectangular domains in both two- and three-dimensions are developed and analyzed. Different from a few sixth-order compact finite difference schemes in the literature, the finite difference and weight coefficients of the new methods have analytic simple expressions. One of the new ideas is to use a weighted combination of the source term at staggered grid points which is important for grid points near the boundary and avoids partial derivatives of the source term. Furthermore, the new compact schemes are exact for 2D and 3D Poisson equations if the solution is a polynomial less than or equal to 6. The coefficient matrices of the new schemes are $M$-matrices for Helmholtz equations with wave number $K≤0,$ which guarantee the discrete maximum principle and lead to the convergence of the new sixth-order compact schemes. Numerical examples in both 2D and 3D are presented to verify the effectiveness of the proposed schemes.     

固体发动机保险机构在高温高压下的实验研究

针对固体发动机部件保险机构所出现破现象,对其进行了激光散斑和电阻应变法联合测试。由于保险机构在高温和高压环境下工作,材料有蠕变现象,出现较大的热变形,传统的光我法实施,发展了一种叠合散斑技术,使之能够对大变形进行非接触式测量,在实验室测试的基础上,对保险机构进行了热容器试验,测量了点火后应变随时间的变化规律。实验结构发现,在保险机构机体上存在着一个接近破环应力的高危应力区,这是保险机破坏的主要因素     

结构优化设计的KFD方法及其在电除尘器本体结构优化中的应用

电除尘器本体结构优化设计是一个规模大,设计变量数多而具有相当难度的几何可调和拓扑可调优化设计问题。对这样一个大型复杂的结构优化问题,本文在文[1]的工作基础上,充分利用结构的力学特性,应用有效设计变量的概念,建立了不用求偏导数且不必解线性规划的可行方向法—KFD方法。该方法具有收敛速度快、占用内存少的优点,比通常ε有效约束可行方向法提高速度数十倍。实际应用的结果表明文中的方法是很有效的。     

Benchmark solution of angle-ply piezoelectric-laminated cylindrical panels in cylindrical bending with weak interfaces

The bending problem of a simply supported, angle-ply piezoelectric-laminated cylindrical panel in cylindrical bending with weak interfaces is considered. A general spring-layer model is adopted to describe the weakness of imperfect interfaces. An exact analysis is performed via the state-space approach. A new system of physical variables is introduced and a variable substitution technique is employed to derive a state equation with constant coefficients. Numerical results are given to show the effect of weak interfaces.The work was supported by the National Natural Science Foundation of China (No. 10372088) and by the Korea Institute of Science and Technology Evaluation and Planning.     

地质工程计算机辅助设计支持系统及其应用

地质工程设计具有非结构化、非参数化、非规范化特征,同时,也具有“风险与优化”性和“反馈与可变更”性。仅用一种固定的、程式化的求解方法是不现实的。因此,必须寻求一种非结构化的工具,根据问题的需要,面向目标自动生成求解结构。本文归纳了地质工程设计的基本内容,探讨了基于几何和基于人工智能的计算机辅助地质工程设计。最后,介绍了地质工程设计支持系统在长江三峡链子崖危岩治理工程设计中的应用。     

Zundel‐like and Eigen‐like Hydrated Protons on a Platinum Surface

The nature of hydrated protons is an important topic in the fundamental study of electrode processes in acidic environment. For example, it is not yet clear whether hydrated protons are formed in the solution or on the electrode surface in the hydrogen evolution reaction on a Pt electrode. Using mass spectrometry and infrared spectroscopy, we show that hydrogen atoms are converted into hydrated protons directly on a Pt(111) surface coadsorbed with hydrogen and water in ultrahigh vacuum. The hydrated protons are preferentially stabilized as multiply hydrated species (H₅O₂⁺ and H₇O₃⁺) rather than as hydronium (H₃O⁺) ions. These surface‐bound hydrated protons may play an important role in the interconversion between adsorbed hydrogen atoms and solvated protons in solution.     

Analyses of the TCR repertoire of MHC class II-restricted innate CD4+ T cells

Analysis of the T-cell receptor (TCR) repertoire of innate CD4⁺ T cells selected by major histocompatibility complex (MHC) class II-dependent thymocyte–thymocyte (T-T) interaction (T-T CD4⁺ T cells) is essential for predicting the characteristics of the antigens that bind to these T cells and for distinguishing T-T CD4⁺ T cells from other types of innate T cells. Using the TCR^mini Tg mouse model, we show that the repertoire of TCRα chains in T-T CD4⁺ T cells was extremely diverse, in contrast to the repertoires previously described for other types of innate T cells. The TCRα chain sequences significantly overlapped between T-T CD4⁺ T cells and conventional CD4⁺ T cells in the thymus and spleen. However, the diversity of the TCRα repertoire of T-T CD4⁺ T cells seemed to be restricted compared with that of conventional CD4⁺ T cells. Interestingly, the frequency of the parental OT-II TCRα chains was significantly reduced in the process of T-T interaction. This diverse and shifted repertoire in T-T CD4⁺ T cells has biological relevance in terms of defense against diverse pathogens and a possible regulatory role during peripheral T-T interaction.     

Epstein–Barr virus latent genes

Latent Epstein–Barr virus (EBV) infection has a substantial role in causing many human disorders. The persistence of these viral genomes in all malignant cells, yet with the expression of limited latent genes, is consistent with the notion that EBV latent genes are important for malignant cell growth. While the EBV-encoded nuclear antigen-1 (EBNA-1) and latent membrane protein-2A (LMP-2A) are critical, the EBNA-leader proteins, EBNA-2, EBNA-3A, EBNA-3C and LMP-1, are individually essential for in vitro transformation of primary B cells to lymphoblastoid cell lines. EBV-encoded RNAs and EBNA-3Bs are dispensable. In this review, the roles of EBV latent genes are summarized.