Imaging Photoelectron Circular Dichroism in the Detachment of Mass-Selected Chiral Anions

Photoelectron Circular Dichroism (PECD) is a forward-backward asymmetry in the photoemission from a non-racemic sample induced by circularly polarized light. PECD spectroscopy has potential analytical advantages for chiral discrimination over other chiroptical methods due to its increased sensitivity to the chiral potential of the molecule. The use of anions for PECD spectroscopy allows for mass-selectivity and provides a path to simple experimental schemes that employ table-top light sources. Evidence of PECD for anions is limited, and insight into the forces that govern PECD electron dynamics in photodetachment is absent. Here, we demonstrate a PECD effect in the photodetachment of mass-selected deprotonated 1-indanol anions. By utilizing velocity map imaging photoelectron spectroscopy with a tunable light source, we determine the energy-resolved PECD over a wide range of photon energies. The observed PECD reaches up to 11 %, similar to what has been measured for neutral species.     

Improved Chernoff Bound of Gaussian Q-function with ABC algorithm and its QAM applications to DB SC and MRC systems over Beaulieu–Xie channels

In this study, we propose an improved upper bound for the Gaussian Q function by using artificial bee colony algorithm. Then, we investigate the performance of the dual-branch (DB) selection combining (SC) and maximal ratio combining (MRC) systems over the Beaulieu–Xie fading channels. The probability density functions of the instantaneous signal to noise ratio for the considered systems are obtained. Employing the proposed upper bound, we derive closed-form expressions of the error probability for the quadrature amplitude modulation (QAM) techniques such as rectangular QAM (RQAM), cross QAM (XQAM), and hexagonal QAM (HQAM). Furthermore, the asymptotic error probability expressions for the DB SC system are also obtained to simplify the analyses. The effects of some key parameters in the systems are shown in the results. Comparisons of the different modulation types and the different upper bound approaches for the Gaussian Q function are presented. Finally, it has been shown that the upper bound approximation presented in this study can be widely used for many communication applications.     

功能化核酸适体的筛选及分子识别应用

核酸适体是从寡核苷酸文库中筛选获得的一段单链寡核苷酸. 由于能与多种靶标分子高特异性结合, 核酸适体已发展成为一种新兴的分子识别工具, 广泛应用于生物医学等领域. 天然核酸文库有限的化学组成限制了核酸适体的结构和功能, 进而限制了其在分子识别中的应用. 功能化核酸适体通过引入特定的化学官能团使核酸序列具有更丰富的构象和功能, 增强其分子识别能力. 然而, 功能化核酸很难与核酸扩增方法兼容, 因而难以使用传统筛选方法进行功能化核酸的筛选. 因此, 优化筛选方法对于获得具有优异性能的功能化核酸适体至关重要. 本综述总结了功能化核酸适体的筛选方法, 并介绍了其作为分子识别工具在生物医学领域中的应用.     

基于差示扫描量热法的火工品材料选型研究

通过综合分析差示扫描量热法(DSC)图谱及动力学数据,进行火工品中药剂外包覆材料的选型研究。采用DSC测试炸药与不同涂敷层材料在不同升温速率的热性质,利用Ozawa法和DSC曲线对比法,对几种涂敷层材料进行分析。炸药与丙烯酸清漆混合后,DSC曲线表观性征、峰温以及反应的活化能变化最小;炸药与快速固化剂混合后,峰温及活化能变化影响居中,DSC曲线表观性征在升温速率大时有较大变化;炸药与硅橡胶混合后,DSC曲线表观性征、峰温以及反应的活化能变化最大。从而确定丙烯酸清漆为最合适的炸药包覆材料。     

DNA酶: 筛选、 生物传感及展望

综述了脱氧核糖核酸酶(DNA酶)的起源及分离富集策略, 对比了DNA酶与核糖核酸酶(RNA酶)及蛋白酶的相似点和不同之处, 并重点讨论了产物捕获和对冲抵消等策略对筛选获得DNA酶的独到之处; 同时系统回顾了近年来分离出的可特异感应各种金属离子或生物样本(包括细菌、 细胞等), 从而能在特定位点切割RNA底物的DNA酶探针; 阐述了DNA酶领域现存的挑战, 总结和展望了新思路和新方向.     

Fixed points, selections and common fixed points for nonexpansive-type mappings

We study the existence of fixed points in the context of uniformly convex geodesic metric spaces, hyperconvex spaces and Banach spaces for single and multivalued mappings satisfying conditions that generalize the concept of nonexpansivity. Besides, we use the fixed point theorems proved here to give common fixed point results for commuting mappings.     

The Sharkovski? Theorem for spaces of measurable functions

We formulate a generalization of the so-called Random Sharkovski? Theorem from paper by Jan Andres, which is the randomized version of the classical Sharkovski? Theorem. We use the method of transformation to deterministic case involving the Kuratowski-Ryll-Nardzewski selection theorem, which allows us to omit the assumption of completeness of the incorporated measurable space. Moreover, we formulate an analogue of the Sharkovski? Theorem for spaces of measurable functions and for Lp-spaces.     

The effects of a new selection operator on the performance of a genetic algorithm

In this study, the new back controlled (BCSO) selection operator for genetic algorithm (GA) is presented. In the first stage, six existing operators and the BCSO were applied to the traveling salesman and space truss benchmark problems. An analysis of the results of the benchmark problems was made for each of the seven selection operators. In the second stage, the BCSO, the Roulette Wheel, dominant selection the hybrid II and operators were used to determine the fittest beam section has been used. In this stage, the cost of beam for a 18.3 m span developed by Mid-Atlantic States Pre-stressed Concrete Committee for Economic Fabrication and using a genetic algorithm the cost of a beam using BCSO were compared. It was determined that the beam produced using the proposed BCSO selection operator would be lower than those obtained with the existing selection operators. Also the determined beam cost is compares favourably with the average cost of a beam sold by the precast industry in the USA.