CARBON ORDERING IN Fe-1.83C MARTENSITE Ⅰ. Crystal Structure of a Conventional Ordered Phase

采用电子衍射方法对Ｆｅ－１．８３Ｃ马氏体室温时效时产生的有序相结构进行研究，确定其结构为偏离化学计量成分Ｆｅ_４Ｃ的γ′－Ｆｅ_４结构，称为γ′－Ｆｅ_ｘＣ（Ⅰ）（ｘ＝４－１１）。碳原子位于单胞的１／２，１／２，１／２位置。该有序相单胞尺寸为：（ａ_Ｍ，ｃ_Ｍ分别为马氏体单胞的ａ和ｃ轴长度），它与母相完全共格，位向关系为（００１）_Ⅰ∥（００１）_Ｍ，［１００］_Ⅰ∥［１１０］_Ｍ。根据γ′－Ｆｅ_ｘＣ（Ⅰ）晶体结构计算出的有序相衍射花样与实验得到的衍射花样全部吻合。     

Development of Reference Shunt for Short‐Time Alternating High Current Tests and Study of Measuring System

Short‐circuit tests for power circuit breakers and others require alternative short‐time current measurement, from a few kA to over several tens kA. However, the reference measurement system as a national standard or a specified secondary standard instrument to directly perform comparative test as a complete calibration test in high current class has not yet been established globally. The Japan Short‐Circuit Testing Committee (hereinafter referred to as “JSTC”) has therefore developed a shunt resistor that can be used as a standard instrument for high current measurement. Reference system using this shunt resistor is also considered by JSTC. The performance of the newly developed shunt resistor has been checked through several methods, such as resistance measurement, high power current test, high frequency current test, temperature rise test, and interference test. The results of the tests proved satisfactory performance. Resistance of the shunt resistor before and after the tests was invariant and stable. This makes the shunt resistor adequate for a reference in practical use. In addition, evaluation of uncertainty of the whole reference system including this shunt resistor satisfactorily fulfills the requirements of IEC 62475 edition 1.0, 2010.     

Solution to the inverse regulator problem for discrete-time systems

A complete solution is given for the inverse problem of LQ optimal regulators for the discrete-time multi-input case. The Kalman equation for discrete-time systems is derived to characterize the optimal regulators. It is then shown that this equation holds for some quadratic weighting if and only if the feedback satisfies a condition corresponding to the circle criterion for continuous-time systems. The optimality criterion given here consists of this condition and an additional condition to ensure detectability. An example is given to illustrate the results.     

Feedback realizations in linear multivariable systems: model-following with stability and disturbance rejection

This paper deals with the problems of constructing a compensator for linear multi-variable systems that simultaneously ensures: (I) model-following with stability and (ii) disturbance rejection. Necessary and sufficient conditions for the solvability of the problems are given by using a geometric approach. The solvability conditions are explicit and the constructive procedure for finding a solution does not require any additional conditions for the plant.     

KINETICS OF BIOETHANOL PRODUCTION FROM WHEAT MILLING BY-PRODUCTS

An overview of the potential application of wheat milling by‐products as substrate for bioethanol production is presented. In order to select a suitable microorganism, model fermentations were conducted using glucose and dry baker's yeast. The overall ethanol yield was nearly stable (ca. 0.35 g/g), independent of mash glucose concentration; mashes with 100 g glucose/L resulted in an overall ethanol productivity of 3.48 g/L·h. Slurries containing low‐grade wheat flour (LG) (100, 200 or 300 g/L) were used for simultaneous saccharification and fermentation (SSF) with Zymomonas mobilis. Fermentation performance was evaluated based on ethanol concentration (P), productivity (Q_v), yield (Y_P/S), production rate (Q_p) and glucose consumption rate (Q_s). Mashes containing 200 g LG/L produced about 52 g ethanol/L, with Q_vof 2.17 g/L·h. Based on the relatively high fermentation rate of LG, reaching peak ethanol productivity within ca. 9 h of SSF, considerable savings on fermentation time was achieved. Using Z. mobilis for LG fermentation, P was about 30% higher than that obtained with Saccharomyces cerevisiae.     

Comparison of Transparent Gels with Turbid Gels Prepared from Egg White: Creep Analysis of Gels

Egg white from which the precipitate occurring during dialysis against water had been removed gave a transparent gel on heating at lower salt concentrations and pH 3.54. The addition of NaCl or a shift of pH from 3.54 to 4.50 brought about the turbid gels. Creep analyses of these transparent and turbid gels were done using a four-element mechanical model. The instantaneous elastic modulus, E₀, Newtonian modulus, ηn and retarded viscoelastic moduli, E₁ and η₁ increased with NaCl up to 125 mM and then decreased with increase in NaCl concentration at pH 3.54. At 125 mM NaCl and pH 3.54, a translucent gel was obtained. E₀ and η₁ decreased with the temperature of the gel, while E₁ and η₁did not change depending of temperature.     

Novel active-R synthesis of a driving-point impedance

A novel active-R synthesis baaed on the single-pole rolloff characteristics of operational amplifiers is described. Various types of driving-point impedance, such as an inductance, frequency-dependent negative-resistance and frequency-dependent negative-inductance are systematically derived by the suitable choice of the amplifier transfer function. It is shown by experiments that the inductance simulator presents reliable high frequency performance.