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.     

Energy‐Efficient Train Speed Profile Generator Combining Partial Energy‐Oriented Driving Approaches

One way of reducing the energy consumption of trains is to drive them in an energy‐efficient manner. There can be various driving patterns between two adjacent stops, or various speed profiles, because there is a gap called the running time supplement between the planned running time set in a timetable and the shortest possible running time of the train. Previous studies have proposed using up the supplement by changing the driving operation from powering to coasting at optimal points in terms of energy consumption. Others have shown that full use of regenerative braking helps save energy. In this study, we developed an energy‐efficient speed profile generator by combining these partial energy‐oriented driving approaches when the planned running time is given. We added this generator to existing shortest running time calculation software, so that it works for various vehicle and train route data. Numerical experiments showed that our profile provided superior performance compared to manually created ones for artificial and real data.     

Denaturation of Bovine Serum Albumin (BSA) and Ovalbumin by High Pressure, Heat and Chemicals

Both native and denatured protein samples were examined by determining fluorescence and specific rotation, and by polyacrylamide gel electrophoresis (PAGE) and differential scanning calorimetry (DSC). Denaturation of ovalbumin by pressure was much less than by heat or by the chemical denaturants. Ovalbumin was denatured under high pressure, as confirmed by the decrease in its a-helical content to 72% and DSC endothermic enthalpy to 61%, but it showed no change in the PAGE pattern. With bovine serum albumin decrease in fluorescence was observed after denaturation by chemicals, but it did not change under high pressure.     

CATHEPSIN D AND ITS EFFECTS ON MYOFIBRILLAR PROTEINS: A REVIEW1

The molecular and enzymatic properties of the extensively studied enzyme cathepsin D are reviewed and additional information concerning its activity presented. Cathepsin D at pH 5.5 (37°C) degraded several myofibrillar proteins. The most rapidly hydrolyzed included titin and perhaps nebulin, myosin heavy chain, and M and C-proteins. The effects of cathepsin D on myofibrillar structure under these conditions included reduction in A band width, cleared central region in the A band, and dislocation of the Z line. Temperature was found to exert a strong influence on activity of cathepsin D and maximum activity was observed at 45°C with both muscle and hemoglobin substrates. Activity was evident at even higher temperatures and approximately 49% remained at 55°C (hemoglobin assay). Low temperature (i.e., < 15°C) however, has been observed to result in almost complete inactivity of the enzyme. The implications of this information for involvement of cathepsin D in postmortem proteolysis and tenderization were discussed.     

Soft-X-ray damage to biological samples

X-ray damage to biological samples was investigated in the wavelength region of 2.7–5 nm, which overlaps the so-called 'water window', the wavelength range of 2.4–4.3 nm usually used in X-ray microscopy. Yeast cells and myofibrils were chosen as representatives of whole cell samples and motile protein systems, respectively. The samples were exposed to X-rays using an apparatus composed mainly of a laser-plasma X-ray source, a Wolter mirror condenser, and a sample cell. The yeast cells lost their dye exclusion ability when the X-ray flux was higher than 1 × 10⁶ photons μm⁻², while the myofibrils lost contractility when the X-ray flux was higher than 4 × 10⁵ photons μm⁻². These X-ray fluxes are lower than the flux required for the X-ray microscope observation of biological samples at a resolution higher than that of light microscopes.     

A High‐Efficiency Single‐Phase Utility Interactive Inverter with an Active Power Decoupling Function and its Control Method

The present paper introduces a single‐phase utility interactive inverter with a power decoupling function. In a conventional single‐phase inverter, power pulsation at twice the grid frequency appears in the input power. Hence, electrolytic capacitors having large capacitances have been connected to the DC input terminal to stabilize the input DC‐bus voltage. Because the lifetime of the electrolytic capacitor is relatively shorter than that of another component, the lifetime of the inverter is affected by the capacitor. In order to prevent such a problem, a novel single‐phase inverter circuit with an active power decoupling function is introduced. The pulsating power on the input DC‐bus line and the pulsated energy on the input DC capacitor is transferred to the energy in a small film capacitor. Hence, the extension of the inverter lifetime can be expected by substituting a small film capacitor for the large electrolytic capacitors. In addition, the loss in the power decoupling circuit is very small; hence, the reduction in the overall conversion efficiency of the inverter can be minimized. The effectiveness of the proposed method is verified using a 300 W experimental setup.     

Effect of Cathepsin D on Bovine Myofibrils under Different Conditions of pH and Temperature

Purified cathepsin D was incubated with bovine skeletal muscle myofibrils under in virro conditions resembling those found in postmortem muscle. SDS-PAGE analysis of myofibrils treated at pH 5.5 and 37°C and the sedimented, showed degradation of myosin heavy chains and titin. A small amount of actin, tropomyosin, troponins T and I, and myosin light chains also were degraded. The cathepsin D treated myofibrils were not fragmented to any greater extend than untreated myofibrils. Raising the pH and/or lowering the temperature greatly reduced the effectiveness of cathepsin D suggesting that the enzyme does not play a principal role in the tenderization process occurring in muscle postmortem.     

Iron Loss Characteristics of Electrical Steel Sheet under Inverter Excitation by Power Semiconductor with Extremely Low On‐Voltage Property

In this study, it is demonstrated that the iron loss from the SiC‐MOSFET, which represents a new power semiconductor with an extremely low on‐voltage for electric machine drives, is almost the same as that from an Si‐IGBT, which is a conventional power semiconductor. In order to evaluate the iron loss characteristics when an SiC device is used, two single‐phase pulse width modulation inverters were built and used for the excitation of a ring made up of electrical steel sheet. One of the inverter employed an SiC‐MOSFET, and the other inverter employed an Si‐IGBT. The iron losses for the two inverters are compared.