Simultaneous Monitoring of Nitrogen Dioxide and Aerosol Concentrations with Dual Path Differential Optical Absorption Spectroscopy

Differential optical absorption spectroscopy (DOAS) is a useful technique for measuring nitrogen dioxide (NO2) and aerosol, the most important species in urban environmental pollution. This paper reports on the results of our dual path DOAS measurements recently conducted in Chiba City, Japan, using xenon flashlights equipped on tall constructions as aviation obstruction lights. Because of the proximity of the southern DOAS path to an industrial area, it is found that the level of air pollution generally increases with the dominance of westerly winds, from the plausible source area to the observation light path. This situation is consistent with the result of wind lidar measurement covering a sector of ±28? with the observation range of approximately 2.8 km. In spite of the fact that the two DOAS paths, having path lengths of 5.5 and 3.5 km each, are located in separated regions of Chiba City, the observed temporal behavior was similar for both nitrogen dioxide and aerosol, though the southern path tends to exhibit slightly higher pollution levels than the northern counterpart. Additionally it is confirmed that size information of aerosol particles can be derived from the DOAS data through the analysis of the wavelength dependence of the aerosol optical thickness, which shows fairly good correlation with the mass ratio between PM2.5 and suspended particulate matter (SPM) obtained from the in-situ sampling station measurement. Thus, the DOAS approach can also be utilized for obtaining information on PM2.5 that is considered to be more harmful to human health than SPM.

A Hybrid Decoupled Power Flow Method for Balanced Power Distribution Systems

This paper proposes a hybrid decoupled power flow method for balanced power distribution systems with distributed generation sources. The method formulates the power flow equations in active power and reactive power decoupled form with polar coordinates. Second-order terms are included in the active power mismatch iteration, and constant Jacobian and Hessian matrices are used. A hybrid direct and indirect solution technique is used to achieve efficiency and robustness of the algorithm. Active power correction is solved by means of a sparse lower triangular and upper triangular （LU） decomposition algorithm with partial pivoting, and the reactive power correction is solved by means of restarted generalized minimal residual algorithm with an incomplete LU pre-conditioner. Typical distribution generation models and distribution load models are included. The impact of zero-impedance branches is explicitly modeled through reconfiguring of the adjacent branches with impedances. Numerical examples on a sample distribution system with widespread photovoltaic installations are given to demonstrate the effectiveness of the proposed method.

Advanced oxidation processes of decomposing dichloroacetic acid and trichloroacetic acid in water

We studied the decomposition of two haloacetic acids (HAAs),dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA),in water by single oxidants ozone (O3) and ultraviolet radiation (UV) and the advanced oxidation processes (AOPs) constituted by the combinations of O3/UV,H2O2/UV,O3 /H2O2,and O3/H2O2/UV. The concentrations of HAAs were analyzed at specified time intervals to track their decomposition. Except for O3 and UV,the four combined oxidation processes remarkably enhance the decomposition of DCAA and TCAA owing to the generated very reactive hydroxyl radicals. The fastest decomposition process is O3/H2O2/UV,closely followed by O3/UV. DCAA is much easier to decompose than TCAA. The kinetics of HAA decomposition by O3/UV can be described well by a pseudo first-order reaction model under a constant initial dissolved O3 concentration and fixed UV radiation. Humic acids and HCO3-in the reaction system both decrease the decomposition rate constants for DCAA and TCAA. The amount of H2O2 accumulates in the presence of humic acids in the O3/UV process.

Nonlinear Bayesian Estimation： From Kalman Filtering to a Broader Horizon

This article presents an up-to-date tutorial review of nonlinear Bayesian estimation. State estimation for nonlinear systems has been a challenge encountered in a wide range of engineering fields, attracting decades of research effort. To date,one of the most promising and popular approaches is to view and address the problem from a Bayesian probabilistic perspective,which enables estimation of the unknown state variables by tracking their probabilistic distribution or statistics(e.g., mean and covariance) conditioned on a system's measurement data.This article offers a systematic introduction to the Bayesian state estimation framework and reviews various Kalman filtering(KF)techniques, progressively from the standard KF for linear systems to extended KF, unscented KF and ensemble KF for nonlinear systems. It also overviews other prominent or emerging Bayesian estimation methods including Gaussian filtering, Gaussian-sum filtering, particle filtering and moving horizon estimation and extends the discussion of state estimation to more complicated problems such as simultaneous state and parameter/input estimation.

Preozonation of bromide-bearing source water in south China

The effectiveness of preozonation was evaluated on treating a bromide-bearing dam source water in south China through batch-scale experiments. Preozonation at ozone doses of 0.5-1.0 mg/L （at ozone consumption base） enhanced total organic carbon （TOC） removal through coagulation, and resulted in an almost linear reduction of ultraviolet absorbance at 254 nm （LW2s4）. The removals of TOC （after coagulation） and UV254 at the ozone dose of 1.0 mg/L were 36% and 70%, respectively. Preozonation at an ozone dose between 0.5 and 1.0 mg/L resulted in the removal of disinfection byproducts formation potential （DBFP） including trihalomethane formation potential （THMFP） and haloacetic acid formation potential （HAAFP） for about 50%. The removals of THMFP and HAAFP decreased with the further increase of ozone dose. Ozonation of bromide-bearing water （bromide concentration, 34 μg/L） produced a bromate concentration under the detection limit（2μg/L） at ozone doses 〈1.5 mg/L. However, bromate 〉10μg/L could be produced when the bromide concentration was increased to 96 μg/L.

DBF雷达中高精度多目标检测

本文介绍了能以高速度、高精度同时完成多目标角度测量的方法。这种方法是借助多普勒滤波器、数字波束形成(DBF)和单脉冲技术在多普勒领域和空域内完成目标测量。

Data-Driven Global Robust Optimal Output Regulation of Uncertain Partially Linear Systems

In this paper, a data-driven control approach is developed by reinforcement learning (RL) to solve the global robust optimal output regulation problem (GROORP) of partially linear systems with both static uncertainties and nonlinear dynamic uncertainties. By developing a proper feedforward controller, the GROORP is converted into a global robust optimal stabilization problem. A robust optimal feedback controller is designed which is able to stabilize the system in the presence of dynamic uncertainties. The closed-loop system is ensured to be input-to-output stable regarding the static uncertainty as the external input. This robust optimal controller is numerically approximated via RL. Nonlinear small-gain theory is applied to show the input-to-output stability for the closed-loop system and thus solves the original GROORP. Simulation results validates the efficacy of the proposed methodology.

Numerical Simulation of Jet Issuing Diagonally Upward into Density-Stratified Fluid in Cylindrical Tank

This study simulates the behavior of a jet issuing into a two-layer density-stratified fluid in a cylindrical tank and the resulting mixing phenomena. The upper and lower fluids are water and an aqueous solution of sodium chloride (NaCl), respectively, with the lower fluid issuing diagonally upward from a nozzle on the bottom of the tank. The angle between the centerline of the jet and the tank bottom is 60°. The phenomena when the Reynolds number Re of the jet is 475, 1426, and 2614 are simulated. The mass concentration of the aqueous solution of NaCl is 0.02. The simulation successfully grasps the jet behavior and the resulting mixing, which agree with the authors’ experimental results at the corresponding Re value. The secondary flows that appear in the horizontal cross-sections consist of a pair of vortices and flows along the tank wall. The secondary flow at the density interface represents the intrusion of an internal density current, which gives rise to mixing along the interface.

Behavior of a Jet Issuing Diagonally Upward into Two-Layer Density-Stratified Fluid in a Cylindrical Tank

This study is concerned with the experimental investigation of a jet issuing diagonally upward into a two-layer density-stratified fluid in a cylindrical tank and the resulting mixing phenomena. The upper and lower fluids are water and an aqueous solution of sodium chloride (NaCl), respectively, and the lower fluid issues from a nozzle on the bottom of the tank. The angle between the centerline of the jet and the bottom of the tank is 60o, and the mass concentration of the NaCl solution is 0.02. The investigation reveals that secondary flow is caused by the jet in the horizontal cross-sections of the tank and that it is composed of a pair of vortices. It confirms that the secondary flow at the density interface corresponds to an internal density current. The investigation also clarifies the effect of the Reynolds number of the jet on mixing between the lower and upper fluids.

各种现场总线系统的高速度

更优秀的产品研发、生产,质量和技术服务是三菱电气的一贯追求,在这一目标要求的指导下三菱电气公司非常清楚地知道自己应该做什么、怎么做。通过他们当前在技术创新领域中的投资,使其在产品研发的道路上不断进步,并在2008年的汉诺威展览会期间向世人展示了其iQ平台的控制方案(见图1):将SPS、Motion Control、CNC和机器人技术结合在一起。

Moisture Detection of SF_6 Gas Instruments by Solid Electrolyte

Humidity measurement in a very low moisture atmosphere was studied by using solid electrolyte film coated with porous electrodes,considering its application to the moisture monitoring of SF_6 gas-insulated high voltage instruments such as gas-insulated switchgear (GIS) and gas circuit breakers (GCBs).Compared to the AC impedance values measured in an ambient atmosphere where the moisture atmosphere is far higher than that in these instruments,considerably large impedance values were obtained in a very low moisture atmosphere.The impedance was systematically measured in accordance with the conditions of these instruments whose moisture contents were less than 1 000×10^(-6).A good correlation was obtained between the impedance values and the moisture contents.The frequency characteristics of the impedance were analyzed based on a conventional equivalent circuit where a number of CR circuits were connected in series.Considering the dielectric relaxation of each circuit,it was found that the frequency characteristics of the impedance can be explained by the equivalent circuit. Two semicircles were clearly obtained in the Cole-Cole impedance plot which are thought to reflect the impedance characteristics of the film and the electrodes.The AC impedance can be a good indicator of the moisture content of SF_6 gas-insulated high voltage instruments.

DBF雷达的自适应零点波束形成

本文介绍用凹口滤波器的ANBF(自适应零点波束形成)。在32单元的线阵天线上的实验证实了ANBF的效果。

利用平面阵列的数字波束形成

本文论述了平面阵列天线中数字波束形成的两种算法。这些算法考虑到了各个接收机和各天线单元的特性。数字波束形成天线现已制作出来,实验的结果进一步证明这些算法具有实用价值。

运用卡尔曼滤波的DBF雷达跟踪系统的最佳化

本文所论及的系统由雷达传感头和卡尔曼滤波器组成。该DBF雷达的脉冲相参积累数是可调整的,此积累数影响到雷达精度和滤波能力。当它很大的时候雷达部分可得到精确的观测,而当它很小时则便滤波能力增加,可发现存在一个最佳数目。

Analysis of Nonequilibrium Transport Properties of Interacting Quantum Wire Models

We analyze nonequilibrium electronic transport properties of a typical interacting three-site quantum wire model within Hartree-Fock approximation making use of Keldysh formalism. Some rigorous formulas are provided for direct calculations when Coulomb repulsion is present. According to numerical calculations using above formulas, we investigate the conductance, transport currents, and on site electronic charges of the wire on some special occasions in the interacting case, and also compare them with the results in the noninteracting case.

Numeric and Analytic Investigation on Phase Diagrams and Phasetransitions of the ν = 2/3 Bilayer Fractional Quantum Hall Systems

The phase diagrams and phase transitions of a typical bilayer fractional quantum Hall (QH) system with filling factor ν = 2/3 at the layer balanced point are investigated theoretically by finite size exact-diagonalization calculations and an exactly solvable model. We find some basic features essentially different from the bilayer integer QH systems at ν = 2, reflecting the special characteristics of the fractional QH systems. The degeneracy of the ground states occurs depending on the difference between intralayer and interlayer Coulomb energies, when interlayer tunneling energy (ΔSAS) gets close to zero. The continuous transitions of the finite size systems between the spin-polarized and spin-unpolarized phases are determined by the competition between the Zeeman energy (ΔZ) and the electron Coulomb energy, and are almost not affected by ΔSAS.

An Approximate High Gain Observer for Speed-sensorless Estimation of Induction Motors

Rotor speed estimation for induction motors is a key problem in speed-sensorless motor drives. This paper performs nonlinear high gain observer design based on the full-order model of the induction motor. Such an effort appears nontrivial due to the fact that the full-model at best admits locally a non-triangular observable form(NTOF), and its analytical representation in the NTOF can not be obtained. This paper proposes an approximate high gain estimation algorithm, which enjoys a constructive design, ease of tuning, and improved speed estimation and tracking performance. Experiments demonstrate the effectiveness of the proposed algorithm.

由紧凑型高dI／dt门极驱动单元驱动的新型对称门极换流晶闸管

在工业大功率应用领域已经推出了多种类型(对称、非对称以及逆向导通)的门极换流晶闸管(GCT)器件。为了用它来实现更高性能、更加合适的系统,人们期望对门极换流晶闸管展开进一步的研究。本文提出了对称门极换流晶闸管的一种新方案。

“Magicpro-NAVI MILL/LATHE on PC for700/70”的开发

“Magicpro-NAVI MILL On PC for 700／70”“Magicpro-NAVI LATHE On PC for 700／70”是使MIT-SUBISHI CNC700／70系列产品上配置的简易程序创建功能“NAVI MILL”、“NAVI LATHE”能在市售PC上进行操作的软件。通过本软件，操作员可在PC上创建与现场CNC700／70系列“NAVI MILL”、“NAVI LATHE”相同的NC程序。

变频传动装置助力食品加工

能够按要求配置揉面机运转速度的传动装置,帮助面包房改进面团的质地,让面包的烘烤更加均匀。在将面团倾倒入提升碗时,其速度非常关键。