An efficient approach for the prediction of ion channels and their subfamilies

Ion channels are integral membrane proteins that are responsible for controlling the flow of ions across the cell. There are various biological functions that are performed by different types of ion channels. Therefore for new drug discovery it is necessary to develop a novel computational intelligence techniques based approach for the reliable prediction of ion channels families and their subfamilies. In this paper random forest based approach is proposed to predict ion channels families and their subfamilies by using sequence derived features. Here, seven feature vectors are used to represent the protein sample, including amino acid composition, dipeptide composition, correlation features, composition, transition and distribution and pseudo amino acid composition. The minimum redundancy and maximum relevance feature selection is used to find the optimal number of features for improving the prediction performance. The proposed method achieved an overall accuracy of 100%, 98.01%, 91.5%, 93.0%, 92.2%, 78.6%, 95.5%, 84.9%, MCC values of 1.00, 0.92, 0.88, 0.88, 0.90, 0.79, 0.91, 0.81 and ROC area values of 1.00, 0.99, 0.99, 0.99, 0.99, 0.95, 0.99 and 0.96 using 10-fold cross validation to predict the ion channels and non-ion channels, voltage gated ion channels and ligand gated ion channels, four subfamilies (calcium, potassium, sodium and chloride) of voltage gated ion channels, and four subfamilies of ligand gated ion channels and predict subfamilies of voltage gated calcium, potassium, sodium and chloride ion channels respectively.     

用于宫颈癌筛查的光电联合检测系统

为了提高宫颈癌的早期筛查效率以合理分配医疗资源,研制了基于光电联合检测的宫颈癌早期筛查系统.系统顶端放置的光电极手持探头采用电脉冲、红光、绿光及近红外光交替分时刺激宫颈组织,通过光电激励和测量,计算得到组织的光电学特征参数——电压衰减常数和相对反射率,用组织分类算法实现了宫颈癌变的判别.将313例临床检验数据与组织病理检验金标准比对,建立了光电激励下组织响应临床数据库.组织分类结果表明,光电联合检测方法比单独光或电的检测在灵敏度、特异性和总符合率上有较大的提高,与组织病理检验结果的对比表明本文所研发系统总符合率达85.1%,对早期宫颈癌的筛查尤其是落后地区宫颈癌的筛查具有重要意义.     

Optimization of field grading for a 1000 KV wide-band voltage divider

An HVDC reference voltage divider has been designed for high accuracy and wide-band measurements up to 1000 kV. To maintain wide-band characteristics, field distribution must be optimized in order to minimize the response time of the divider. To compensate the stray capacitance, a capacitive path that surrounds the resistive reference divider is added to function as a shield. Optimal capacitance values producing a matched distribution are obtained using 3D FEM simulations. Factors affecting the performance of the divider are assessed by simulating multiple scenarios representing different practical considerations in real-life applications.     

Transient electric charging of dielectric liquids in recirculation systems

This paper describes a transient electric charging phenomenon due to flow-induced electrification during a cold startup of dielectric liquids in a recirculation system. This transitory effect exhibits itself as a static voltage spike in the system. It is argued that simultaneous rise in the liquid temperature and the circulation flow rate can generate conditions for such electrostatic voltage spikes to exist. These spikes have been verified experimentally in the laboratory and we report qualitative agreements between the reported experimental data and the theoretical considerations. With a cold start, this transient charging has the potential to induce a large static voltage and large space charge in the circulating system that can damage other components.     

同类型理想电源联接问题的讨论

在电路分析基础等教材的“电压源与电流源”章节中，介绍了不同类型理想电源的联接，但未深入讨论同类型理想电源的联接问题。该问题长期以来困扰着广大的初学者。本文从电源的电路结构和数学模型的角度出发，利用极限的概念，论证了同类型理想电压源在并联使用及同类型理想电流源在串联使用的时候，其输出电压、电流值的不确定性。并说明在什么样的条件下这种联接才有实际意义。     

Calculation of Mutual Coupling between Two RLTs in Millimeter Wave VCO Waveguide Cavities with Mode Matching Methods

In the design of millimeter wave voltage control oscillators (VCOs), mutual coupling effect is of great importance for it influences the tuning and power characteristics of VCOs significantly. In this paper, mutual coupling between two in-line radial line transformers (RLTs) in rectangular waveguide cavities of millimeter wave VCOs has been evaluated with mode matching methods. Mutual coupling characteristics varying with various parameters of resonate cavity such as the distance between two diodes, the position of sliding short, the radii of bias pins, the radii of RLTs, and the height of diodes are presented. Some useful conclusions concerning two RLTs configuration have been derived, which is helpful to design millimeter wave VCO of this structure.     

带自检显示功能的中频放大器的研制

文中介绍带自检显示功能的中频放大器的设计思路和测试结果.该组件具有技术性能稳定、可靠、自检显示功能反应灵敏、直观等特点.     

提高智能温度测控系统精度的几个措施

采用提高采样频率的方法使系统成为准连续系统，以VFC和PWM作为计算机温度测控系统的模数和数模转换器件均可有效地提高系统的精度，并降低成本.     

Revisiting the Comellas-Fiol-Gómez constructions of large digraphs of given degree and diameter

We analyze three constructions of Comellas and Fiol [F. Commellas, M.A. Fiol, Vertex-symmetric digraphs with small diameter, Discrete Applied Mathematics 58 (1995) 1-11] that produce large digraphs of given diameter and degree from smaller starter digraphs. We show that these constructions preserve coverings in the sense that if the starter digraph is a regular lift (in particular, a Cayley digraph), then the resulting digraph has the same property.     

Step-by-step implementation of an amplifier circuit with a graphene field-effect transistor on a printed-circuit board

Power amplifier circuits are implemented with graphene field-effect transistors (FETs), capacitors and inductors, and their gain is improved step-by-step by adjusting the passive components. The transistors are fabricated on a 150-mm wafer using conventional complementary-metal-oxide semiconductor processing along with graphene transferring processes. The completed circuit is implemented on a printed circuit board, which allows for adjustment of the external capacitance and inductance to study the performance of graphene RF FETs. A maximum signal gain of 1.3 dB is achieved at 380 MHz. The device parameters of the transistors are then extracted and the gain is analyzed, and the results show that lowering the source–drain conductance and gate resistance is the key in realizing high performance circuits.