New oxygen donors formed at 700 °C in silicon

Donor formation at 700 °C was studied by infrared absorption, etching, transmission electron microscope, resistivity, and spreading resistance measurements in Czochralski grown silicon. The donor concentration is related to the oxygen-precipitate density, oxygen reduction, and carbon reduction by annealing at 700 °C. The donor distribution corresponds to the distribution of oxygen precipitates observed after annealing. The proposed donor is an oxygen precipitate nucleated at a carbon site. The oxygen-related donor formation not only occurs in the bulk of samples but also in the denuded zone. Donor-related microdefects do not seriously influence the threshold voltage in metal-oxide-silicon field-effects-transistors, but are expected to decrease carrier lifetime at the surface of the denuded zone.     

The Study and Development of Roll Heat Pipe Performance

A new type of heat pipe called roll heat pipe (RHP) is considered in this study. In RHP, the evaporator and the condenser are separated in the radial direction, and the energy is moved in radial direction. RHP is composed of two concentric annular pipes of unequal diameter, wick structure, and bridge wicks, which provide the return path of the working fluid to evaporator. A heat source is inserted in the inner pipe, which works as the evaporator region. RHP can be applied as heat roll in the laser printers or copy machines where isothermal heating as well as rapid response is desired. Three RHP samples are fabricated and tested in this work. They differ in the number of bridge wicks and inner tube diameter. The length of all samples is 300 mm. In this paper, the transient thermal characteristics of RHP samples are investigated experimentally and compared with numerical analysis results. Also, the effects of fill charge on the performance of RHP samples are studied. By using infrared thermography camera, we observed that the level of temperature uniformity on the outer surface of heat roll is very good in comparison with real heat roll.     

Determination of phosphorous and sulfur in environmental samples by electrothermal vaporization inductively coupled plasma atomic emission spectrometry

From the viewpoint of selective introduction of the analyte from its solvent and matrices, electrothermal vaporization (ETV) is useful for the sample introduction into the inductively coupled plasma (ICP). By using a tungsten boat furnace (TBF) vaporizer system, the loss of analyte phosphorus, which normally occurs during the drying and ashing stages, is suppressed. The phosphate ion is reacted with the tungsten supplied from the surface of the TBF to form stable tungsten phosphate species. Regarding the determination of sulfur, additional chemical modifiers such as copper(II), lead(II), etc., are necessary to retain the analyte on the TBF. The furnace-fusion (FF) method or wet-digestion technique on the TBF is applied to unify the chemical forms of the analytes. Various oxidative and reductive inorganic compounds as well as organic compounds of phosphorus and sulfur show the same sensitivities after the FF digestion with hydrogen peroxide. The detection limits are 1.5 ng and 0.12 ng for phosphorous and sulfur, respectively. The repeatabilities in terms of the relative standard deviations of 10 replicate measurements of phosphorus and sulfur are 4.2% and 2.0%, respectively. Finally, the established method is applied to the determination of several environmental waters.     

Collaboration work for nuclear power building using 3D CAD information

In the construction work for the Unit No.5 Turbine Building at Hamaoka Nuclear Power Station, the collaboration work for the planning and the coordination of the building construction and the machinery installation was carried out utilizing three-dimensional computer aided design (3D CAD) information. It was the first time in Japan for a building constructor and a plant manufacturer to work together, exchanging 3D CAD data of the whole building and adjusting the construction schedule. It was made possible to confirm the correspondence concerning the planning of both companies from the primary stage of the project by the total process simulation and to adjust on-going work precisely by the partial process simulation.     

电子探针在钕铁硼磁性材料表征中的应用

钕铁硼稀土永磁材料在新能源汽车等行业的电机领域中应用十分广泛.使用岛津电子探针波谱仪的点分析、线分析和面分析功能对钕铁硼磁性材料微区的基体相微观特征、化学组成和分布以及晶界扩散以提高矫顽力的工艺方法进行了直观地表征,可为磁体制备新技术和微观机理的阐述提供数据参考,对生产工艺的技术改进、质量管理和失效分析等整个过程可予以...     

发电不确定性条件下电动汽车对智能家居能量管理的贡献

光伏、风电等可再生能源的大规模接入给电力系统的运行带来了诸多问题,如由发电过剩引起的电网反向潮流、电网频率和节点电压调节容量的不足。作为解决可再生能源出力波动性引起的不确定性问题的方法之一,采用电动汽车作为储能装置,即所谓的V2H（vehicle to house）或者V2G（vehicle to grid）,将发挥重...     

Pressure-pulsed chemical vapour infiltration of SiC into two-dimensional-Tyranno/SiC particulate preforms from SiCl4–CH4–H2

SiC was infiltrated in two-dimensionally woven Tyranno/SiC particulate preforms from SiCl₄–CH₄–H₂ using pressure-pulsed chemical vapour infiltration (PCVI) in the temperature range 1348–1423 K. Above 1373 K, only β-SiC was deposited, whereas, at 1348 K, Si codeposition was found. At 1423 K, a macrosurface film was formed in the early stage of PCVI. At 1373 K, residual porosity decreased from 30% to 7.5% irrespective of the sample size. Three point flexural strength increased with decreasing residual porosity and increasing fibre volume fraction in the sample. Flexural strength of the sample having 48% fibre volume fraction reached about 325 MPa after 5 × 10⁴ pulses of CVI at 1373 K. Inter-laminar shear strength of the sample obtained at 1373 K reached 40 MPa at 7 × 10⁴ pulses. This revised version was published online in November 2006 with corrections to the Cover Date.     

Eigenvalue-based wide area stability monitoring of power systems

Background oscillations are utilized for the real-time stability evaluation of electric power systems. After identifying the parameters of the low-order discrete-time model for the target system from the background oscillations measured at two different locations, the stability of the target system has been evaluated through the eigenvalues of the identified discrete-time model. Real-time simulations have been performed for a longitudinal four-machine infinite-bus system on the Analog Power System Simulator at the Research Laboratory of the Kyushu Electric Power Co. to demonstrate the efficiency of the proposed scheme. The accuracy of the proposed scheme for the real-time stability evaluation has also been clarified through the comparisons with the alternative stability evaluation in the time domain, and also in the frequency domain.     

Wavelength dependence of Fe(ll) photoformation in the water-soluble fraction of aerosols collected in Okinawa, Japan

We studied photoformation of Fe(II) in the water-soluble fractions (WSFs) of bulk aerosol particles collected in Okinawa, Japan, using radiation at wavelengths of 313, 334, 366, and 405 nm. Fe(II) photoformation quickly reached a steady state within 5 min of irradiation at all wavelengths. The steady-state Fe(II) concentrations were 85+/-13% (n = 39) of the total dissolved Fe (TDFe) concentrations in the WSF solutions. Apparent quantum yields of Fe(II) photoformation were determined based on total absorbance of the WSF solutions, and the means (+/-1 S.D.) were 0.019 (+/-0.034), 0.021 (+/-0.031), 0.014 (+/-0.023), and 0.010 (+/-0.025) at 313, 334, 366, and 405 nm, respectively. Comparison of the observed rates of Fe(II) photoformation for the WSF solutions and the calculated rates from the known Fe(II)-forming compounds suggested that Fe(oxalate)2- could account for the observed Fe(II) photoformation rates if the Fe(oxalate)2- concentration is sufficiently high (>20% of [Fe(III)]o). Furthermore, our study showed that the calculated wavelength dependence of Fe(ll) photoformation from Fe(oxalate)2- was consistent with that of Fe(II) photoformation observed in the WSF solutions. The results obtained here have implications to daytime Fe(III)/ Fe(II) cycles in the atmospheric water droplet.