Operation control of photovoltaic/diesel hybrid generating system considering fluctuation of solar radiation

The exhaust gas emission from marine diesel engines is one of the major environmental issues. The authors have been studying the use of photovoltaic energy for the electric power system on ships. This paper proposes an operation control of a photovoltaic/diesel hybrid generating system for a small ship in consideration of the fluctuating photovoltaic power due to solar radiation. The aim of the control is to minimize the fuel consumption and storage capacity of the battery. The validity of the proposed control method is shown by the numerical simulation based on the experimental data of a photovoltaic system.     

Theoretical analysis of the effect of conduction band offset of window/CIS layers on performance of CIS solar cells using device simulation

One of the most important factors of CdS leading to high performance in Cu(In,Ga)Se₂ (CIGS) solar cells is appropriation of the conduction band offset of CdS/CIGS layers. However, it is not clearly explained. In this study, device modeling and simulation were conducted to explain the effect of conduction band offset of window/CIGS layers on performance of CIGS solar cells. As a result of calculation, excellent performance can be obtained when the conduction band of window layer positions higher by 0–0.4 eV than that of CIGS.     

Studies on high‐speed melt spinning of noncircular cross‐section fibers. II. On‐line measurement of the spin line,including change in cross‐sectional shape

On‐line measurement was performed in the high‐speed spinning of flat, hollow, and circular fibers of poly(ethylene terephthalate), paying particular attention to the change in cross‐sectional shape along the spin line. The diameter profiles of hollow and circular fibers were essentially identical, whereas the deformation of flat fiber shifted to the region closer to the spinneret. The necklike deformation of hollow and circular fibers started at the takeup velocity of 5 km/min. In the case of flat fibers, presence of the necklike deformation was confirmed at 4 km/min, and extremely steep diameter attenuation was observed at 5 km/min. The spin‐line tension of the flat fiber was also larger than that of circular fibers. Combined measurements of fiber velocity and thickness enabled us to evaluate the aspect ratio of the flat fiber and hollow ratio of the hollow fiber in the spin line. These two factors were found to decrease steeply near the spinneret. Accordingly, the thinning of the spin line and the change in cross‐sectional shape appeared to proceed independently. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1582–1588, 2001     

Influence of Aluminum–Oxygen–Yttrium Solid Solution on the Aqueous Tribological Behavior of Silicon Nitride

To investigate the influence of crystal structure and solid solutions of certain elements in Si₃N₄ on aqueous tribological properties, seven specimens were fabricated. Solid solutions of aluminum and oxygen made the friction coefficient and wear increase in both α-type and β-type crystal structures. In particular, α-SiAlON, in which yttrium is also incorporated into the α-Si₃N₄ lattice, showed a higher friction coefficient and wear than other specimens containing the same concentration of Al or O.     

EUV Optical Design-Reflective and Diffractive Optics

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AN EXPERIMENTAL STUDY OF THE STRIP CASTING PROCESS OF ALUMINUM ALLOY BY THE TWIN ROLL METHOD

Experimental studies on the twin roll casting process in order to produce thin aluminum alloy strips are presented in this paper. A new twin roll caster was developed as an effective experimental tool. The caster is equipped with a complete casting system incorporating a control and measuring system using multiple sensors and various actuators. The data acquisition system of the caster can measure various process parameters including meniscus, casting speed, and temperature as well as roll gap and pressure. With this system, aluminum alloy thin strips were manufactured and the process parameters such as strip temperature, casting velocity, and pressing force of roll were investigated. Furthermore, the crystallizability, microstructure, and mechanical properties of the strip are evaluated by X-ray diffractometer, scanning electron microscope, and tensile test. The results revealed the ability of the twin roll caster to produce directly the thin strip of aluminum alloy with improved mechanical strength.     

金属有机物分解法制备的La0.67Ca0.33MnOz薄膜的磁输运特性

利用金属有机物分解法在石英衬底上制备了多晶La0.67Ca0.33MnOx薄膜。研究了薄膜输运特性及其与温度的关系,发现薄膜的金属－半导体转变温度Tp(约172K）远低于其居里温度（约247K）;在平行于膜面的1T磁场下,77K－302K温度范围内,没有磁电阻（MR）峰,而是在Tp温度以下,有一宽的平台,平台处MR值约为21％－24％,在Tp温度以上,MR随温度上升而迅速降低;在77K温度上,薄膜具有显著的低场磁电阻效应。上述磁输运特性与载流子在晶界附近的输运行为如强的自旋相关散射和晶粒间自旋极化隧道效应等有关。在77K温度下,还观察到退磁效应引起的磁电阻垂直各向异性。     

A series of InGaP/InGaAs HBT oscillators up to D-band

In this paper, the development of a series of fixed-frequency heterojunction bipolar transistor (HBT) oscillators from the W- to D-bands is reported. The oscillators are designed based on feedback theory with a small-signal equivalent circuit. This design method enables the achievement of high-output-power oscillators for the management of the power that is generated at the current source inside the HBT. We use a 1 μm×10 μm single-emitter InGaP/InGaAs HBT as an active device for each oscillator, and 50-Ω coplanar waveguides as transmission lines and resonators. Emitter output topology is adopted to reduce the chip size. The series of oscillators achieve the oscillation frequency of 74.8-146.7 GHz. To our knowledge, the 146.7-GHz fundamental oscillation frequency is the highest oscillation frequency achieved thus far using InGaP/InGaAs HBT technology. The output power of the 146.7-GHz oscillator is -18.4 dBm. The chip size of the oscillator is 731 μm×411 μm     

Organic air pollutants inside and outside residences in Shimizu, Japan: levels, sources and risks

Concentrations of 38 organic air pollutants including aromatic hydrocarbons (AHCs), carbonyl compounds (CCs), volatile organic halogenated compounds (VOHCs), and organophosphorus compounds (OPCs) were measured in indoor and outdoor air in an industrial city, Shimizu, Shizuoka Prefecture, Japan. Levels of pollutants tended to be higher indoors than outdoors in both summer and winter except for benzene, carbon tetrachloride, trichloroethylene, tetrachloroethylene, and dichlorvos (DDVP). This trend was especially pronounced for CCs such as formaldehyde and acetaldehyde. For the organic air pollutants, the concentrations of AHCs and VOHCs substantially increased in winter, but not those of CCs and OPCs; the trends were similar for both indoors and outdoors. We investigated possible indoor sources of pollutants statistically. Multiple regression analysis of corresponding indoor and outdoor concentrations and the responses to our questionnaire showed that indoor concentrations of certain AHCs were significantly affected by their outdoor concentrations and cigarette smoking. For formaldehyde, indoor concentrations were significantly affected by house age and the presence of carpet or pets. For p-dichlorobenzene (pDCB), the concentrations in bedroom trended to be higher than those in other indoors and outdoors, suggested that mothballs for clothes present in bedrooms are the principal indoor source of pDCB. We compared indoor and outdoor pollutant concentrations to acceptable risk limits for 11 organic air pollutants. In indoors without smoking samples, the geometric mean concentrations of benzene, formaldehyde, acetaldehyde, carbon tetrachloride, pDCB, and DDVP exceeded the equivalent concentration representing the upper bound of one-in-one-hundred-thousand (1x10(-5)) excess risk over a lifetime of exposure.     

Effective Catalysts for Wet Oxidation Of Formic Acid by Oxygen and Ozone

The catalytic wet-air oxidation and catalytic ozonation of a formic acid solution have been studied at room temperature using more than 20 kinds of catalysts including Pt/C, Pt/Al₂O₃, Pd/Al₂O₃, etc. The most effective catalyst was Pt/Al₂O₃. The apparent activation energies for the catalytic wet-air oxidation and ozonation on Pt/Al₂O₃ were both about 5 kcal/mol. This fact suggests that these reactions on the catalyst were diffusion controlled, and thus, the potential of the catalyst is likely much higher.