Effect of TiB2 and Boron Additions on the Stability of Wurtzite-Type Boron Nitride at High Temperatures and Pressures

Shock-synthesized wurtzite-type BN(w-BN) and mixtures of w-BN–TiB₂ and w-BN–ß were treated at high temperatures and pressures. The effect of TiB₂ and boron additions on the transformation of w-BN to zinc blende-type BN(z-BN) was studied at 1000° to 2200°C and 55 to 68 kbars. The formation region of z-BN was shifted toward higher temperatures by TiB₂ additions and toward lower temperatures by boron additions.     

Switched-capacitor discrete Fourier analyser with window function circuit

An analogue window function circuit is realized by using switched-capacitor techniques. In order to verify the effect of this window, a novel switched-capacitor analogue discrete Fourier analyser is proposed. The window function circuit is included in this analyser as the ratios of capacitances. This switched-capacitor discrete Fourier analyser is very simple in construction, namely, only two elemental circuits based on the integral feedback capacitance circuit are connected in series. Agreement between the experimental and the theoretical values is confirmed.     

Fast method of interpolation for frequency estimation of sinusoidal and spindle data

Estimating the frequency of one or more sinusoidal waves is a problem belonging to the field of signal analysis. The frequency characteristics of sinusoidal waves can be measured by peaks or troughs of the waves. Because of (he limit of the sampling frequency, the peaks or troughs of sinusoidal and EEG waves in the sampling usually deviate from their original ones in the time domain. Starting from a sinusoidal wave analysis, we present a correction formula with which the deviation time t_d can be calculated so as to detect the position of the real peak or trough of the data as fast and as accurately as possible on the time axis. The wave of the sleep spindle in the EEG can be considered as an asymmetrical sinusoid. Then after the waves have been filtered, the formula can also be applied to analyse the spindle of EEG waves and it is shown to be useful in the measurement of the frequency of the spindle wave. Error analysis and practical examples are presented.     

Dietary Flavonoids as Potential Natural Biological Response Modifiers Affecting the Autoimmune System

In vitro anti-complement activity of 19 phenolic compounds was evaluated in the classical pathway. Two flavonoids, epigallocatechin gallate and myricetin, exhibited marked anti-complement activities with IC₅₀ values of 4.2 and 5.2 μg/mL (concentration causing 50% inhibition of complement activity), respectively. The two flavonoids appeared to interact with both antibody-sensitized erythrocytes and complement components to inhibit the cascade reactions in the classical pathway of the complement system. The flavonoids may function as natural biological response modifiers by multiple mechanisms including anticomplement effects. Dietary flavonoids may thus affect the body's autoimmune system.     

Specific Disulfide Bond in α-Lactalbumin Infiuences Heat- Induced Gelation of α-Lactalbumin-Ovalbumin-Mixed Gels

The gel strength of ovalbumin mixed with α-lactalbumin (α-La) was determined after heating at 80°C for 15 min at pH 7.0 Gel strength of the mixture of 4%α-La and 4% ovalbumin was two times that of 8% ovalbumin. Modified α-La at Cys6-Cys120 (3 SSα-La) had low enhancement effects on ovalbumin gelation. Competitive ELISA using monoclonal antibody to α-La showed decreased binding reactivities after heating α-La with ovalbumin at specific concentrations. The decrease of total SH groups in the gel mixed with 3SS α-La was much less than when mixed with α-La. A disulfide bond of Cys6-Cys120 in α-La contributed to interactions between ovalbumin and α-La in heat-induced gels.     

Extraction of Volatile Compounds from Aqueous Solution using Micro Bubble, Gaseous, Supercritical and Liquid Carbon Dioxide

When separating volatile compounds from aqueous solution using supercritical carbon dioxide (SC CO₂), methods to bring SC CO₂ into contact with volatile compounds in the solution are very important. An extraction using micro bubble, gaseous, supercritical, and liquid CO₂ generated by a filter nozzle was carried out. Under optimal conditions (20 MPa, 35°C), > 95% of volatile compounds consisting of 6 to 12 carbon atoms could be removed by extraction for 40 min at CO₂ flow rate, 4.0 g/min. Extraction at 35°C could achieve either a selective or nonselective separation by adjusting the extraction pressure, since the effect of pressure on extraction ratio was most significant at 35°C.     

Sampled-data charge processor

A general-purpose analogue signal processor is presented in which all operations are performed in a charge domain. The processor can be customized to each application according to an instruction program. The processor is composed of amplifiers, analogue switches, capacitors and a memory. Charge-domain processing techniques and a calibration technique are used to reduce the requirement for a capacitor precision-ratio. An application to bandpass filtering is demonstrated.