Design of a reaction field using a linear‐combination‐based isotropic periodic sum method

In our previous study (Takahashi et al., J. Chem. Theory Comput. 2012, 8, 4503), we developed the linear‐combination‐based isotropic periodic sum (LIPS) method. The LIPS method is based on the extended isotropic periodic sum theory that produces a ubiquitous interaction potential function to estimate homogeneous and heterogeneous systems. The LIPS theory also provides the procedure to design a periodic reaction field. To demonstrate this, in the present work, a novel reaction field of the LIPS method was developed. The novel reaction field was labeled LIPS‐SW, because it provides an interaction potential function with a shape that resembles that of the switch function method. To evaluate the ability of the LIPS‐SW method to describe in homogeneous and heterogeneous systems, we carried out molecular dynamics (MD) simulations of bulk water and water–vapor interfacial systems using the LIPS‐SW method. The results of these simulations show that the LIPS‐SW method gives higher accuracy than the conventional interaction potential function of the LIPS method. The accuracy of simulating water–vapor interfacial systems was greatly improved, while that of bulk water systems was maintained using the LIPS‐SW method. We conclude that the LIPS‐SW method shows great potential for high‐accuracy, high‐performance computing to allow large scale MD simulations. © 2014 Wiley Periodicals, Inc.     

Reliability of Speaking and Maximum Voice Range Measures in Screening for Dysphonia

Speech range profile (SRP) is a graphical display of frequency-intensity occurring interactions during functional speech activity. Few studies have suggested the potential clinical applications of SRP. However, these studies are limited to qualitative case comparisons and vocally healthy participants. The present study aimed to examine the effects of voice disorders on speaking and maximum voice ranges in a group of vocally untrained women. It also aimed to examine whether voice limit measures derived from SRP were as sensitive as those derived from voice range profile (VRP) in distinguishing dysphonic from healthy voices. Ninety dysphonic women with laryngeal pathologies and 35 women with normal voices, who served as controls, participated in this study. Each subject recorded a VRP for her physiological vocal limits. In addition, each subject read aloud the "North Wind and the Sun" passage to record SRP. All the recordings were captured and analyzed by Soundswell's computerized real-time phonetogram Phog 1.0 (Hitech Development AB, T?by, Sweden). The SRPs and the VRPs were compared between the two groups of subjects. Univariate analysis results demonstrated that individual SRP measures were less sensitive than the corresponding VRP measures in discriminating dysphonic from normal voices. However, stepwise logistic regression analyses revealed that the combination of only two SRP measures was almost as effective as a combination of three VRP measures in predicting the presence of dysphonia (overall prediction accuracy: 93.6% for SRP vs 96.0% for VRP). These results suggest that in a busy clinic where quick voice screening results are desirable, SRP can be an acceptable alternate procedure to VRP.     

Remarkably improved cycling stability of 3D porous Cu–Sn anode for lithium-ion full cells by adjusting working voltage range

Numerous studies confirm that three dimensional porous Cu–Sn (3DP Cu–Sn) anode possesses good application prospect in light of its desirable electrochemical performance on lithium ion half cells, but there are a few related systematic researches on lithium ion full cells until now, which is indispensable before its commercialization. Herein, the effects of galvanostatic charge-discharge voltage range on the cycling stability of 3DP Cu–Sn anode for lithium ion full cells are investigated systematically. The results show that the suitable charge-discharge voltage range plays a key role in improving the reversible capacity and cycling stability of the 3DP Cu–Sn||LiCoO₂ full cell, which is closely related to maintaining the electrode structure stable by controlling the amount of Li⁺ extracted and inserted. Especially, in the voltage range of 1.2–3.9 ​V, the full cell exhibits remarkably improved electrochemical properties with the high initial reversible capacity of 2.71 ​mAh cm⁻² and 71.95% capacity retention upon 80 cycles. We believe that this work can provide a significant reference for the practical application of porous Sn-based anodes.     

Towards a microchannel‐based X‐ray detector with two‐dimensional spatial and time resolution and high dynamic range

X‐ray detectors that combine two‐dimensional spatial resolution with a high time resolution are needed in numerous applications of synchrotron radiation. Most detectors with this combination of capabilities are based on semiconductor technology and are therefore limited in size. Furthermore, the time resolution is often realised through rapid time‐gating of the acquisition, followed by a slower readout. Here, a detector technology is realised based on relatively inexpensive microchannel plates that uses GHz waveform sampling for a millimeter‐scale spatial resolution and better than 100 ps time resolution. The technology is capable of continuous streaming of time‐ and location‐tagged events at rates greater than 10⁷ events per cm². Time‐gating can be used for improved dynamic range.     

On the Nano/Micro-Mechanics of Metallic Glass

Metallic glass (MG) is amorphous and has some outstanding properties such as ultrahigh strength, superior elasticity, and excellent thermo-plasticity. However, as MG is relatively new to the metal family, the relationship between its physical properties and amorphous structure is still unclear. This article aims to provide an insightful discussion through a comprehensive review about the investigations in the past few decades on the scientific mechanisms of this class of material. The discussion of the paper will include the following key aspects: (1) the formation mechanism of an amorphous structure through glass transition, (2) the structural characterization and models, (3) the micromechanics of plastic event and shear band, and (4) the correlation between the amorphous structure and its mechanical properties.     

关于一元酸准确滴定判据的商榷

化学分析教科书中给出的弱酸能被准确滴定的条件是cKa≥1.0×10-8。本文根据这一判据的来源(滴定突跃≥0.3pH单位),对一元酸体系的滴定情况进行了严格数学处理。计算结果表明,只有同时满足弱酸的浓度c1.0×10-3mol/L和cKa≥1.0×10-8条件下,弱酸才能被准确滴定。对于浓度极稀的酸溶液(c≤1.4×10-4mol/L),无论强酸还是弱酸都不能被准确滴定。对教材很少涉及的不同浓度酸碱互相滴定的情况也给出了有价值的结论。     

α‐FeOOH−MoO3 Nanorod for Effective Photo‐Fenton Degradation of Dyes and Antibiotics at a Wide Range of pH

It's highly significant to develop a novel catalyst, which can be active at a wide range of pH, for an effective photo‐Fenton reaction. In this work, α‐FeOOH?MoO₃ nanorod was prepared by a one‐step hydrothermal method and applied in photo‐Fenton degradation of organic pollutants. Benefit from the electron migration mechanism of Z‐scheme and excellent photoelectric performance, the catalyst exhibited superior photo‐Fenton activity in degradation of organic pollutants. In addition, the catalyst holds good stability after 5 recycles. These results demonstrated that this catalyst has wide application prospect in organic wastewater treatment.     

一种基于Retinex理论的图像增强算法

提出了一种基于Retinex理论的图像增强算法。Retinex理论的实质就是从图像S中抛开照射光L的影响来获得物体的反射性质R,即获得物体本来的面貌。在对Retinex理论进行研究的基础上,论述了该算法的原理和实现方法,并通过实验与几种传统的图像增强方法以及单尺度、多尺度和带彩色恢复的多尺度Retinex进行了比较,表明该算法对于图像阴影细节的增强和色彩的保真较一般的图像增强算法能够达到更好的效果。     

一种高性能单反射面柱形紧缩场微波暗室

介绍了一个单反射面柱形紧缩场暗室,分析了柱面紧缩场的工作原理,其原理是采用一维算法将柱面波转换为平面波.整体暗室以紧缩场为基础,通过综合和优化选型,从暗室、吸波材料、紧缩场设备等多个方面配合设计,达到了较好的综合效果,具有很高的测试性能,可用于高精度的天线测量和雷达散射截面测量.     

一种基于TMS320C6416T的激光色域转换方法

为了快速完成荧光色域到激光色域的颜色转换,设计了以高性能的DSP芯片为核心处理器,结合现场可编程门阵列FPGA的实时数字图像处理平台.给出了三组不同波长激光的色域转换矩阵,在基于TMS320C6416T的图像处理平台上实现了两个系统的信号转换,并且利用多种加速算法,加快了处理速度.实验结果表明,本文的方法有效地扩展了激光电视的颜色区域,降低了图像的饱和度.