饱和土与衬砌动力相互作用的圆柱形孔洞内源问题解答

考虑饱和土与衬砌结构的动力相互作用,该文研究了内源荷载作用下圆柱形孔洞的动力响应问题.将饱和土体和衬砌结构分别视为流固耦合介质和弹性均匀介质,通过引入势函数将位移控制方程化为二维轴对称波动方程.采用拉普拉斯变换,得到饱和土体位移应力的表达式及衬砌的位移应力的表达式.利用土体与衬砌结构之间的连续性条件和衬砌结构内边界上的边界条件,确定表达式的未知系数.采用逆拉普拉斯变换的数值方法,给出了问题的数值解.分析了饱和土中圆形衬砌结构随土体和衬砌结构参数变化的动力响应规律.     

翼型厚度对气动弹性特性的影响

结合基于$k$-$\omega$的SST两方程湍流模型,求解雷诺平均Navier-Stokes方程获得定常和非定常气动力,耦合翼型弹性运动方程,在时间域内模拟了不同厚度对称翼型在不同迎角下的气动弹性动态过程,并重点研究了较大迎角下的不同厚度翼型流场特征和气动弹性的性质,研究结果表明：在论文所涉及的参数情况下,对于迎角从零到大迎角范围,翼型颤振临界速度随迎角的变化不是单调的. 翼型颤振临界速度迅速下降的起始迎角比最大升力系数对应的迎角小很多.     

激光诱导金纳米棒图案化光纤SERS探针

研究了激光诱导沉积制备光纤表面增强拉曼散射(SERS)探针,并对探针的SERS性能进行检测。探讨光纤探针制备过程中金纳米棒溶液的浓度对探针灵敏度的影响。结果表明,将不同浓度的金纳米棒溶液进行激光诱导,在光纤端面会形成金纳米棒团簇和分散两种纳米结构。金纳米棒溶液的浓度、激光功率、诱导时间等因素都会对诱导沉积图案产生影响。实验利用功率为5 mW的激光进行诱导,在1.5×10^-9, 1.0×10^-9和7.5×10^-10 mol·L^-1的金纳米棒溶液中,经5 min沉积,制备出不同图案的光纤SERS探针。采用晶种法合成金纳米棒,用透射电子显微镜(TEM)观察金纳米棒形貌,并根据TEM图像分析计算了合成金纳米棒的长径比约为3.8。用扫描电子显微镜(SEM)观察金纳米棒的形貌以及激光诱导沉积后的纤维修饰端形貌,7.5×10^-10 mol·L^-1的金纳米棒溶液进行激光诱导,金纳米棒在光纤端面分布较为分散,而1.5×10^-9和1.0×10^-...     

兰州重离子加速器冷却储存环

 兰州重离子加速器冷却储存环HIRFL-CSR,是一个多用途、多功能的双冷却储存环同步加速器系统,由主环CSRm和实验环CSRe构成,并以兰州重离子级联回旋加速器HIRFL作注入器。CSR利用高频变谐波的方法,将重离子束的能量从7～25 MeV/u同步加速到２00～1 000 MeV/u,同时利用重离子储存环中空心电子束冷却技术将束流品质提高１个数量级,并通过储存环的快引出及慢引出,提供多种类的重离子束以及放射性次级束(RIBs),以开展范围更广精度更高的物理实验。该装置于2007年投入运行,已取得了重要的运行结果,如实现了剥离注入与多圈注入、空心电子束对重离子束的冷却与累积、变谐波宽能区同步加速、等时性环型谱仪、RIBs的产生收集与ToF高分辨质量测量以及高能重离子束的变能慢引出等。     

单原子材料类酶催化及生物医学应用研究进展

纳米酶因其经济、 稳定、 性质可调和可循环利用等诸多优势, 成功地克服了天然酶在实际应用中的不足. 单原子材料的出现使得对纳米酶的研究迈入原子水平, 其较高的原子利用率、 独特的配位环境和较强的金属-载体相互作用为揭示纳米酶构效关系及调控类酶活性提供了可能. 本文总结了近年来单原子材料类酶催化的研究进展, 重点讨论了单原子材料类酶活性的调控策略和催化机理, 概述了单原子类酶材料在癌症治疗、 抗氧化治疗、 抗菌以及生物传感等方面的应用, 并对单原子类酶材料的发展前景进行了展望.     

Polysaccharide-based hemostats: recent developments,challenges, and future perspectives

Cellulose - Excessive hemorrhage is a leading cause of death to trauma patients, especially in combat and civilian accidents. The main priority in the medical treatment of trauma patients is to...     

Polymer Scaffolds for Biomedical Applications in Peripheral Nerve Reconstruction

The nervous system is a significant part of the human body, and peripheral nerve injury caused by trauma can cause various functional disorders. When the broken end defect is large and cannot be repaired by direct suture, small gap sutures of nerve conduits can effectively replace nerve transplantation and avoid the side effect of donor area disorders. There are many choices for nerve conduits, and natural materials and synthetic polymers have their advantages. Among them, the nerve scaffold should meet the requirements of good degradability, biocompatibility, promoting axon growth, supporting axon expansion and regeneration, and higher cell adhesion. Polymer biological scaffolds can change some shortcomings of raw materials by using electrospinning filling technology and surface modification technology to make them more suitable for nerve regeneration. Therefore, polymer scaffolds have a substantial prospect in the field of biomedicine in future. This paper reviews the application of nerve conduits in the field of repairing peripheral nerve injury, and we discuss the latest progress of materials and fabrication techniques of these polymer scaffolds.     

Si-rhodamine based water-soluble fluorescent probe for bioimaging of Cu+

A Si-substituted rhodamine based water-soluble fluorescent probe bearing a tetrathia-azacrown was designed for fluorescence imaging of Cu⁺ with substantial affinity and selectivity.In physiological condition,the developed probe with outstanding water-solubility exhibits ultrahigh sensitivity to Cu⁺,ensuring the reliable fluorescence imaging in vivo.     

Current research progress of photopolymerized hydrogels in tissue engineering

Owing to the special fo rmation of photopolymerized hydrogels,they can effectively control the formation of hydrogels in space and time.Moreover,the photopolymerized hydrogels have mild formation conditions and biocompatibility;therefore,they can be widely used in tissue engineering.With the development and application of manufacturing technology,photopolymerized hydrogels can be widely used in cell encapsulation,scaffold materials,and other tissue engineering fields through more elaborate manufacturing methods.This review covers the types of photoinitiators,manu facturing technologies for photopolymerized hydrogels as well as the materials used,and a summary of the applications of photopolymerized hydrogels in tissue engineering.     

Kinetic Resolution of 2-Substituted 1,2-Dihydroquinolines by Rhodium-Catalyzed Asymmetric Hydroarylation

Main observation and conclusion A highly efficient kinetic resolution of racemic 2-substituted 1,2-dihydroquinolines via Rh-catalyzed asymmetric hydroarylation...