New GTO Current Source Inverter with Pulsewidth Modulation Control Techniques

A new GTO current source inverter in which two auxiliary GTO's are added to the basic inverter circuit, which consists of six GTO's and three capacitors, is presented. One of the auxiliary GTO's is connected between the positive line of the inverter and the neutral of three Y-connected capacitors; another is connected between the negative line and the neutral. In the proposed inverter, the charges of three capacitors are controlled at the same time by means of pulsewidth modulation (PWM) to main GTO's and auxiliary GTO's. This inverter can supply both the sinusoidal current and voltage to the motor. The PWM control technique, the operating principle, and the experimental results for 2.2-kW induction motor drives are described. The output current waveform of this inverter is closely sinusoidal, as opposed to trapezoidal in the basic inverter circuit. The steady-state characteristics of the GTO-CSI induction motor drive system are analyzed by the state-variable methods, and a close agreement between the analyzed and the experimental results is obtained. Smooth and noiseless drive of induction motor over a wide range of speed is observed.     

Characteristics on PWM CSI-induction motor drive system with utility interactive photovoltaic generation

This paper proposes a PWM current source inverter-induction motor drive system with photovoltaic generation. Solar cells are inserted in dc link to obtain constant current characteristics. They are connected to the utility system with a PWM converter. The PWM converter is controlled to obtain the maximum output photovoltaic (PV) power. The PWM inverter supplies sinusoidal currents for an induction motor, which is driven by constant V/f control. A pulsewidth control is utilized in the inverter section because of constant dc link current caused by peculiar V-I solar cell characteristics. In the system proposed here, the PV power is not only used for inverter-induction motor drive but it also flows into the utility system. The experimental results in steady state show that the proposed system has sinusoidal current with unity power factor in the utility system, the maximum output PV power and sinusoidal current/voltage for a motor. The demonstrated results for the separation of the utility system or the motor from the converter-PV-inverter system are given. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 118 (2): 79–87, 1997     

Rapid Reconstitution of Biosynthetic Machinery for Fungal Metabolites in Aspergillus oryzae: Total Biosynthesis of Aflatrem

Reconstitution of the biosynthetic machinery for fungal secondary metabolites in Aspergillus oryzae provides an opportunity both for stepwise determination of the biosynthetic pathways and the total biosynthesis of fungal natural products. However, to maximize the utility of the reconstitution system, a simple and rapid strategy for the introduction of heterologous genes into A. oryzae is required. In this study, we demonstrated an effective method for introducing multiple genes involved in the biosynthesis of fungal metabolites by using the expression vectors pUARA2 and pUSA2, each of which contains two cloning sites. The successful introduction of all the aflatrem biosynthetic genes (seven genes in total) after two rounds of transformation enabled the total biosynthesis of aflatrem. This rapid reconstitution strategy will facilitate the functional analysis of the biosynthetic machinery of fungal metabolites.     

Electrochemical formation of Sm-Co alloys by codeposition of Sm and Co in a molten LiCl-KCl-SmCl3-CoCl2 system

Electrocodeposition of Sm and Co on a Cu substrate was investigated in a molten LiCl-KCl-SmCl₃ (0.5 mol.%)-CoCl₂ (0.1 mol.%) system at 723 K. Phase of the deposited Sm-Co alloys could be controlled by electrolysis potential. SmCo₃ was formed on a Cu substrate by potentiostatic electrolysis in the potential range of 0.20-0.90 V (vs. Li⁺/Li). Sm₂Co₁₇ was obtained in the potential range of 0.90-1.50 V.     

1,2‐propanediol–cellulose–acrylamide graft copolymers

1,2‐Propanediol–cellulose–acrylamide graft copolymers (PCACs) were developed for enhanced oil recovery. They were prepared with acrylamide and 1,2‐propanediol (PDO)–cellulose, which was formed through the addition of glycols to cellulose by the Shotten–Baumann reaction between 3‐chloro‐1,2‐propanediol and cellulose. The graft copolymerization was initiated with a redox system between Ce⁴⁺ and glycols in cellulose. The infrared spectrum of PDO–cellulose had some characteristic absorption bands around 2960 (νC? H) and 1050 cm^?1 (νC? O) that also appeared for the PDO group and pyranose ring of cellulose, respectively. The rate of Ce⁴⁺ consumption by PDO–cellulose was investigated through the calculation of the overall kinetic constant from the slopes of ln(D ? D_R) versus time (where D is the absorbance and D_R is the absorbance of the original polysaccharide solution) The results showed that PDO–cellulose had high reactivity and that there were two mechanisms of oxidation by Ce⁴⁺ with PDO–cellulose. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3022–3029, 2004     

Benchmarks for psychotherapy efficacy in adult major depression.

This study estimates pretreatment-posttreatment effect size benchmarks for the treatment of major depression in adults that may be useful in evaluating psychotherapy effectiveness in clinical practice. Treatment efficacy benchmarks for major depression were derived for 3 different types of outcome measures: the Hamilton Rating Scale for Depression (M. A. Hamilton, 1960, 1967), the Beck Depression Inventory (A. T. Beck, 1978; A. T. Beck & R. A. Steer, 1987), and an aggregation of low reactivity-low specificity measures. These benchmarks were further refined for 3 conditions: treatment completers, intent-to-treat samples, and natural history (wait-list) conditions. The study confirmed significant effects of outcome measure reactivity and specificity on the pretreatment-posttreatment effect sizes. The authors provide practical guidance in using these benchmarks to assess treatment effectiveness in clinical settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Theoretical and evolutionary parameter tuning of neural oscillators with a double-chain structure for generating rhythmic signals

A neural oscillator with a double-chain structure is one of the central pattern generator models used to simulate and understand rhythmic movements in living organisms. However, it is difficult to reproduce desired rhythmic signals by tuning an enormous number of parameters of neural oscillators. In this study, we propose an automatic tuning method consisting of two parts. The first involves tuning rules for both the time constants and the amplitude of the oscillatory outputs based on theoretical analyses of the relationship between parameters and outputs of the neural oscillators. The second involves an evolutionary tuning method with a two-step genetic algorithm (GA), consisting of a global GA and a local GA, for tuning parameters such as neural connection weights that have no exact tuning rule. Using numerical experiments, we confirmed that the proposed tuning method could successfully tune all parameters and generate sinusoidal waves. The tuning performance of the proposed method was less affected by factors such as the number of excitatory oscillators or the desired outputs. Furthermore, the proposed method was applied to the parameter-tuning problem of some types of artificial and biological wave reproduction and yielded optimal parameter values that generated complex rhythmic signals in Caenorhabditis elegans without trial and error.     

Development of a dual‐lamp projector with higher brightness

Stationary projectors mainly used in system applications have recently gained a wider application range, including general presentations in halls and large conference rooms and being used, for example, in digital signage and for monitoring purposes. Consequently, they are required to meet new market demands for durability, reliability, and flexibility in installation in addition to their conventional basic performance such as especially high brightness. To achieve especially high brightness, a new optical system with two lamps is proposed; the profile of the cover glass that prevents the glass from scattering is made aspherical, the profile of the beam‐combining mirror is improved with its position optimized, and the size of the incident plane of the integrator rod is made larger (1.1 times). These measures resulted in an optical system of an even higher efficiency with 7000 lm, which is the highest in its class (according to a June 2010 investigation). Also, the arrangement of two parallel lamps completely eliminated the effect of heat passing from one lamp to the other, which helped secure durability, reliability, and flexibility in installation. Furthermore, the combined use of the unique non‐telecentric optical system, adopted from the conventional single‐lamp model, helps maintain the class‐highest contrast ratio.^1,2     

Development of a novel emitting vinyl polymer and its application in organic electroluminescent devices

Abstract— A novel emitting vinyl polymer, poly[4‐(7‐{4‐[N,N‐bis(9,9‐dimethylfluoren‐2‐yl)amino]phenyl}‐2,1,3‐benzothiadiazol‐4‐yl)phenylethylene] (PVFABT), was designed and synthesized. The new vinyl polymer was found to form smooth amorphous films with a high glass‐transition temperature of 199°C. The polymer possesses bipolar character with both electron‐donating and accepting properties. It undergoes reversible anodic oxidation and cathodic reduction to give stable cation and anion radicals. It exhibits intense orange fluorescence in solution and as film. A multilayer organic electroluminescent device using PVFABT as an emitting material emitted orange light, exhibiting high performance.