Lightning Observation in 3D Using a Multiple LF Sensor Network and Comparison with Radar Reflectivity

A three‐dimensional (3D) lightning mapper consisting of multiple low‐frequency (LF) sensors has been developed to monitor thunderstorms and to estimate their charge structure. We have been conducting an observation campaign using the 3D lightning mapper in Kansai, Japan, since October 2012. In this study, we determine 3D source locations of intracloud and cloud‐to‐ground flashes and compare them with the radar reflectivity estimated by phased‐array radar (PAR) with high temporal and spatial resolution. Most LF sources are located in high radar reflectivity regions, confirming that the 3D LF lightning mapper monitors thunderstorms. A lightning flash with heavy branches is clearly imaged. Based on the bidirectional leader theory that negative and positive ends of a lightning leader develop simultaneously, we estimate the positive and negative charge regions in a thundercloud from the LF source locations. The radar reflectivity estimated by PAR supports the charge structure estimated by LF source locations.     

Diagnosis Criterion of Abnormality of Transformer Winding by Frequency Response Analysis (FRA)

Frequency response analysis (FRA) is a powerful technique to detect internal abnormalities within power transformers. However, diagnosis criteria of power transformers by FRA have not been fully established yet. In this paper, a new evaluation method of degree of identification between two transfer functions is proposed. In the proposed method, a frequency window is employed and cross‐correlation factor is calculated with moving the window. Furthermore, the proposed method is applied to transfer functions of real transformers with or without some abnormalities. Based on this discussion, objective criteria for diagnosis of abnormalities of transformer windings by FRA are proposed. The proposed criteria are based on a few data of transformers with some abnormalities. Therefore, the proposed criteria are tentative and they would be improved by accumulation of further data.     

Optimal control for linear continuous-time systems with general noises based upon sampled data

This paper is concerned with the optimal control problem for continuous-time systems with general noises, based upon sampled data, under the quadratic cost functional. The system is described by a linear stochastic integral equation, the observations are made at discrete times, and the noise processes are not assumed zero-moan Gaussian and/or white. Derived is the optimal controller algorithm, where the optimal input consists of the following two: (1) the optimal input for usual linear-quadratic-Gaussian control systems and (2) its correction input due to the fact that the noise processes arc non-white and have non-zero means.     

微纳V槽脆/塑性域切削的3D激光检测及评价

针对微纳米级功能V槽微细加工及评价困难的问题,采用单点金刚石切削方法在超精密机床上对光学玻璃进行V槽的微纳尺度加工,且利用非接触激光检测技术展现V槽的加工形貌。研究目的是分析V槽的微纳米尺度加工的可行性以及找出如何评价V槽加工精度的方法。首先,采用单点金刚石在光学玻璃上进行V槽的微纳尺度切削试验。然后,利用3D激光超精密检测仪器检测加工的V切痕,构建微V槽切痕的形貌图,建立V槽形状误差PV值和V槽尖角圆弧半径的评价模式。最后,分析在微纳尺度加工中切除深度与V槽角度的形成机理以及切削深度对V槽形状误差及其尖角圆弧半径的作用机制。结果表明,在亚微米级尺度加工中存在一个脆/塑性域切除加工状态转变的临界切削深度。在塑性域切削中,金刚石刀具尖角形状可以复制到工件表面,形成深度小于0.386μm、形状误差PV值约0.103μm、尖角半径约为0.182μm的V槽。此外,V槽形状误差PV值在塑性域切除加工中始终保持不变,但在脆性域切除加工中随着切削深度增大而逐渐剧烈加大。而且,V槽尖角圆弧半径在塑性域切削中随着切削深度减小而减小,但为了获得完整的V槽轮廓还需被控制在V槽成型临界界线以下。因此,在处理非接触激光检测的3D数据的基础上,V槽形状误差PV值和尖角圆弧半径可以用来评价V槽微纳尺寸加工的加工精度和微细程度。     

高效液相色谱法测定六种大豆异黄酮及雌马酚的含量

针对豆制品中同时测定大豆异黄酮和雌马酚方法存在的问题,优化并建立了同时测定6种大豆异黄酮和雌马酚的高效液相检测程序,并测定了几种市售豆乳中大豆异黄酮的含量。采用乙腈/甲醇（v/v,5/2）和水为流动相、流速1.0mL/min、检测波长254nm,6种大豆异黄酮和雌马酚均得到良好的分离,相关系数R2分别为0.9998、0.9989、0.9997、0.9986、0.9998、0.9995、0.9999,线性关系良好。该方法准确、灵敏,适合于豆制品中大豆异黄酮及雌马酚的检测。     

Secretome-microRNA and anti-proliferative APRO family proteins as cancer prevention and stem cell research strategies

Stemness of cancer cells contains limitless self-renewal proliferation. For the purpose of proliferation, secretome might exert its effects via the paracrine signaling. Specific microRNAs enclosed in the secretome of cancer stem cells could regulate the expression of anti-proliferative APRO family proteins. The biological functions of APRO family proteins seems to be quite intricate, however, which might be a key modulator of microRNAs, then could regulate the proliferation of cancer cells. In addition to affecting proliferation/differentiation during cellular development, APRO family proteins might also play an imperious role on keeping homeostasis in healthy stem cells under a physiological condition. Therefore, relationship between the microRNAs and the APRO family proteins has attracted much attention in the field of cancer research and regenerative medicine. Here, we have described the molecular mechanism behind this interplay that have a potential role in the future promising tools with targeting APRO family proteins for the medical applications.     

Dielectric Recovery Characteristics after High‐Frequency Current Interruption in Vacuum Circuit Breaker

When the contacts of circuit breaker are opened just before current zero, the gap between contacts will still be very short. Therefore, it cannot withstand recovery voltage between the contacts. In such a case, multiple reignition is likely to take place. Many investigators had tried to clarify this phenomenon, and many reports have been published. However, high‐frequency current interruption and dielectric recovery characteristics are related to some parameters (value of current, arc time, and so on). In addition, arc phenomenon has also been implicated. Hence, it is difficult to understand this phenomenon accurately. In this paper, we conducted dielectric recovery test and high‐frequency current interruption test. Further, we conducted observation experiment using vacuum chamber in order to investigate the effect of small dc current. At the end, we calculated plasma density in the electrodes after high‐frequency current interruption by considering the result of observation experiment and dielectric recovery test.     

Optimization of linear systems with integral control for time-weighted quadratic performance indices

The necessary conditions to be satisfied by the feedback control constructed by available variables, minimizing time-weighted quadratic performance indices for linear systems incorporating integral action, are developed using the parameter optimization technique. To remove the dependence of the solution on a reference input and an external disturbance, a performance index based on the statistical expectation and a minimax solution are considered. An algorithm based on a gradient technique is given to solve the necessary conditions of the minimax solution. Numerical examples are given to illustrate the effect of a time-weighted performance index on the transient response of the output, and they show that the integral-square-time-square error performance index is acceptable for a reference input.