Impurity Effects on Energy Gap in Bi<Subscript>2</Subscript>Sr<Subscript>2</Subscript>CaCu<Subscript>2</Subscript>O<Subscript>8+<Emphasis Type="Italic">y</Emphasis></Subscript> Investigated by Electronic Raman Scattering

The Raman scattering experiments were carried out in Zn-doped and Zn-free Bi₂Sr₂CaCu₂O_8+y with optimal hole concentration below and above T _c . The energy of pair-breaking peak in the B _1g Raman spectrum, corresponding to the magnitude of superconducting gap 2Δ ₀, is suppressed by 1% Zn-doping. In the normal state, the B _1g Raman spectrum for Zn-doped sample shows no pseudogap behaviour, suggesting that the pseudogap is strongly smeared by Zn-doping.     

Progress in ECRF antenna development for JT-60SA

Structural, mechanical and optical design work on antennas/launchers for the electron cyclotron range of frequency heating and current drive system in JT-60 Super Advanced (JT-60SA) have been advanced based on a linear motion antenna concept. A CAD model of the launcher was built with realistic component sizes. A mock-up of the steering structure consisting of two different bellows sections for poloidal and toroidal beam scanning was fabricated to test movement of the bellows. The poloidal (?40° to +20°) and toroidal (?15° to +15°) injection angle ranges required in JT-60SA were shown to be realized by this steering structure and mirrors.     

Existence states of deuterium irradiated into LiAlO2

The existence states of deuterium in LiAlO₂ were analyzed by in situ IR absorption spectroscopy during irradiation with 3 keV at room temperature. Multiple IR absorption peaks that were related to O-D stretching vibrations were observed, mainly at 2650 cm⁻¹ (O-D_α), 2600 cm⁻¹ (O-D_β), and 2500 cm⁻¹ (O-D_γ). The O-D_α was assigned to the surface O-D. The O-D_β and O-D_γ were interpreted as two distinct O-D states for three candidates: O-D of substitutional D⁺ for Li⁺; O-D of substitutional D⁺ for Al³⁺; and O-D of interstitial D⁺. O-D_β was the dominant O-D state for deuterium irradiated into LiAlO₂, and had higher stability than O-D_γ. Heating after ion irradiation led to the desorption of D₂ and an increase in the intensity of O-D_β, which implies that some of the deuterium irradiated into LiAlO₂ exists in non-O-D states, such as D⁻ captured by F centers.     

67-GHz static frequency divider using 0.2-μm self-aligned SiGeHBTs

A 67-GHz 1/4 static frequency divider using 0.2-μm self-aligned selective-epitaxial-growth SiGe heterojunction bipolar transistors, with a 122-GHz cutoff frequency, a 163-GHz maximum oscillation frequency, and an average emitter coupled logic gate delay time of 5.65 ps, was developed. The pretracking master-slave toggle flip-flop (MS-TFF) of the divider increases the maximum operating frequency to about 15% higher than that of a conventional MS-TFF, yet the power consumption of the divider is 175 mW, which is 1/5 that of comparable dividers, at a supply voltage of -5.2 V     

Exponential ARX model-based long-range predictive control strategy for power plants

For nonlinear thermal power plants whose dynamics vary with load demand, a load-dependent exponential ARX (Exp-ARX) model, which can effectively describe the nonlinear properties of the plants, is presented. The Exp-ARX model requires only off-line identification. Based on the model, a constrained multivariable generalized predictive control (CMGPC) strategy is designed and implemented in a simulation of 375 MW thermal power plants. This CMGPC algorithm does not resort to on-line parameter estimation and can more exactly predict the future outputs of the nonlinear plants, so it shows better reliability and control performance than the usual GPC algorithm.     

Prediction of starting performance of PM motors by DC decay testingmethod

This paper presents a method to predict the direct- and quadrature-axes operational impedances and starting performance of permanent-magnet (PM) motors by a simple standstill response testing method using a small-capacity DC power supply unit. In this method, not only the starting performance but also the direct- and quadrature-axes synchronous machine constants (synchronous, transient, and subtransient reactances) and equivalent circuit constants are calculated. This proposed strategy, tentatively named the DC decay testing method, is carried out on a 3.7-kW 200-V 22. A 100-Hz four-pole interior PM motor with a damper winding. The results measured by on-load tests and those predicted by the proposed method on starting performance demonstrate the validity and usefulness of the proposed method     

统一强度理论的发展及其在土木水利等工程中的应用和经济意义

统一强度理论是在中国本土原创产生和发展起来的关于材料强度和结构强度的系统新理论。它从连续统力学最基本的单元体力学模型开始，到数学建模方法，理论公式的表述，以及一系列新的理论公式都不同于以往的各种理论。它将以往各种适合于某一类材料的单一强度理论推进为可以适合于多种材料的统一强度理论。经过40多年的发展，它不仅自己形成了系统的理论，而且将很多著名的理论包容其中，形成了范围更宽广、功能更强大的理论体系。由于它具有一个统一的力学模型，清晰的物理意义，简单的线性数学表述式，能反映材料的基本特性，即sD效应(不同的抗拉强度和抗压强度)、静水应力效应、正应力效应、中间主应力效应和中间主剪应力效应，以及结构强度分析的破坏准则效应，并且与现有的实验数据相吻合，能容易地适合许多新情况；此外，统一强度理论既容易用来取得解析解，也容易用于计算机程序取得数值解。统一强度理论已被推广应用于很多领域。在连续介质和工程应用的框架下对统一强度理论的发展及其在土木工程中的应用和经济意义进行较为系统的小结。     

Characteristics of translucent alumina produced by slip casting method using gypsum mold

Translucent Al₂O₃ ceramics were successfully produced by slip casting using a gypsum mold, provided that CaSO₄ impurities, which had penetrated into the green bodies from the gypsum mold, were removed by the wash of HCl aqueous solution. Some of the calcined Al₂O₃ compacts were washed with HCl aqueous solution before sintering the compacts and the others were not washed with HCl aqueous solution. The relative densities of the sintered Al₂O₃ ceramics with HCl treatment were higher than those of the untreated samples. Grains in the HCl-treated samples, which sintered at 1350°C, grew homogeneously with about 1 m in diameter. When the sintering temperature was higher, the grains grew homogeneously. The sintered Al₂O₃ ceramics with the HCl treatment were translucent. The transmittance value increased from 0 to 12% with increasing wavelength from 300 to 900 nm. The Al₂O₃ ceramics with the HCl treatment did not have the transmittance when the solid contents of slurry were low. The transmittance was influenced by the solid contents of slurry. On the other hand, grains in the HCl-untreated samples, which sintered at 1350°C, grew heterogeneously with the range from 0.2 to 2 m. The Al₂O₃ ceramics did not have the transmittance.     

Observation of small fatigue crack growth behavior in the extremely low growth rate region of low carbon steel in a hydrogen gas environment

To investigate the effects of hydrogen on crack propagation in the extremely low growth rate range, fully reversed bending fatigue tests were performed on low carbon steel (JIS S10C) in hydrogen and in nitrogen gas environments at a low pressure. A crack showed almost the same non-propagation behavior in nitrogen as that in air. However, a crack in hydrogen continued to propagate even near $10^{7}$ cycles in the same testing strain range as that in nitrogen. In hydrogen gas, a crack grew intermittently by coalescing with a new micro-crack generated by slip behavior. This implies that hydrogen could inhibit the action of any factor affecting non-propagation.     

Thermoelectric properties of β-FeSi2 with B4C and BN dispersion by mechanical alloying

The B₄C- and BN-dispersed -FeSi₂ thermoelectric materials were synthesized by mechanical alloying and subsequent hot pressing. The effects of the B₄C and BN dispersion on the thermoelectric properties, such as Seebeck coefficient, electrical resistivity and thermal conductivity etc., of the -FeSi₂ were investigated. For the sample with B₄C and BN addition, a larger amount of the residual phase was detected in the X-ray diffraction patterns than the sample without addition. In the case of the BN addition, the Seebeck coefficient was enhanced by BN addition above 700 K, and the electrical resistivity also increased with increasing amount of BN. This is considered to result from doping of a small amount of B into the phase due to partial decomposition of the BN phase. The fine dispersion of BN particles in the phase matrix was quite effective for reducing the thermal conductivity as compared to the B₄C addition over the entire temperature range. The figure of merit, Z, of the -FeSi₂ was significantly enhanced by BN addition.