Decrease in alkaline triglyceride lipase in primary cultured hepatocytes from mice with sarcoma 180

Primary cultured hepatocytes from normal mice and mice with Sarcoma 180 were characterized. The viability of freshly isolated heptocytes from both sources was over 90% and the cells had a relatively stable population of DNA for a minimum of three days. After incubation with (³H)leucine, the syntheses and secretions of (³H)labeled trichloracetic acid-insoluble materials by hepatocytes from both normal and tumor-bearing mice increased similarly. However, the alkaline triglyceride lipase activity of a homogenate of freshly isolated hepatocytes from tumor-bearing mice was one-third that of cells from normal mice. the activity of hepatocytes from tumor-bearing mice inceeased less during culture than did the activity of cells isolated from normal mice.     

Weighting matrix of quadratic performance index and design method of optimal deadbeat control system

A method of determination of the weighting matrix of the quadratic performance index and a method of design of an optimal deadbeat control system are discussed. First, the relationship between the weighting matrix of the quadratic performance index and the extra poles of the overparametrized pulse transfer function model is indicated. Next, a method of design of an optimal deadbeat control system is explained. Lastly, to demonstrate the effectiveness of the proposed method, some numerical examples are presented. © 2000 Scripta Technica, Electr Eng Jpn, 133(1): 53–63, 2000     

Usefulness of Permanent Power Fuse in Control Centers with Molded Case Circuit Breakers

The increase in electric power consumption in industry has led to the development of modern distribution systems such as control centers having high kVA ratings and high prospective fault current. In such a situation, the improvement of the system usefulness such as reliability and cost effectiveness is the essential requirement. An index is presented to evaluate the system usefulness using the cost effectiveness for fault protection in a system of given bank kVA. The index is estimated on four different system structures of control centers, including one which utilizes Permanent Power Fuses (PPF). It is presented that the PPF combined with molded case circuit breaker in main circuit effectively improves the cost effectiveness in control centers with high fault current. Operating principles of the PPF and the control center utilizing the PPF are briefly outlined.     

Mesoporous Co3O4 for low temperature CO oxidation: effect of calcination temperatures on their catalytic performance

Mesoporous Co3O4 particles are prepared by using mesoporous silica KIT-6 (with double gyroid Ia-3d symmetry) as a hard-template and Co(No3)2 x 6H2O as an inorganic precursor. In the former section, we investigate the effect of the calcination temperatures at which the Co salts are converted into Co3O4 inside the mesopores on the textural parameters of the products. The results of N2 adsorption-desorption analysis indicates that the calcination temperatures do not obviously affect the textural parameters such as the surface areas and pore volumes. However, when the calcination temperature reaches 800 degrees C, the mesostructural ordering is dramatically decreased, resulting in the reduction of the surface areas and pore volumes. After 800 degrees C calcination, the formation of large Co3O4 grains is partially confirmed on the particle surface by SEM observation. The grain size is much larger than the mesopore size of the original KIT-6, meaning the crystal growth is continuously occurred by breaking the rigid silica frameworks. In the latter section, we discuss the effect of the calcination temperatures and textural parameters on the catalytic activity for CO oxidation by both steady state and kinetic measurements. All mesoporous Co3O4 particles show a high catalytic activity, for example, -72 degrees C for sample calcined at 450 degrees C. Only 10 degrees C difference in T50 (the temperature of 50% conversion of CO) is found between the samples with the highest and lowest catalytic activity. The values of activation energy (Ea) and pre-exponential factor (A) per unit area are almost the same between two samples calcined at 450 degrees C and 800 degrees C. It is demonstrated that calcination process can not alter the essential catalytic property of mesoporous Co3O4 particles.     

Kinetic and morphological study of a magnesium ethoxide‐based Ziegler–Natta catalyst for propylene polymerization

BACKGROUND: Kinetic and morphological aspects of slurry propylene polymerization using a MgCl₂‐supported Ziegler–Natta catalyst synthesized from a Mg(OEt)₂ precursor are investigated in comparison with a ball‐milled Ziegler–Natta catalyst. RESULTS: The two types of catalyst show completely different polymerization profiles: mild activation and long‐standing activity with good replication of the catalyst particles for the Mg(OEt)₂‐based catalyst, and rapid activation and deactivation with severe fragmentation of the catalyst particles for the ball‐milled catalyst. The observed differences are discussed in relation to spatial distribution of TiCl₄ on the outermost part and inside of the catalyst particles. CONCLUSION: The Mg(OEt)₂‐based Ziegler–Natta catalyst is believed to show highly stable polymerization activity and good replication because of the uniform titanium distribution all over the catalyst particles. Copyright © 2008 Society of Chemical Industry     

Effect of oxide film on oxygen reduction current for the platinum-cobalt alloy electrodes in PEFC

Effect of surface oxide on Pt-Co alloy electrodes on the oxygen reduction reaction (ORR) was investigated in 0.5 M sulfuric acid solution by electrochemistry, ellipsometry, laser Raman scattering spectroscopy, and XPS. The oxide as thick as 1-2 nm increases the overpotential of ORR and falls down efficiency of PEFC. The thickness of the oxide films is precisely determined by ellipsometry. The oxide film 1.9 nm thick was formed on Pt-50 mol% Co electrode by constant potential oxidation at 1.20 V and the film 1.5 nm thick remains on the electrode at 0.6 V at which ORR already starts. The remaining oxide decreases the current density of ORR and increases the overpotential. On pure Pt electrode, the similar influence of the oxide film was observed.     

Control of SF6 discharge gap switch by XeCl excimer laser

Experimental studies have been carried out on triggering characteristics of the SF₆ discharge gap switch by use of XeCl excimer laser (wavelength = 308 nm). First, laser irradiation characteristics are studied on a pure SF₆ in the pressure range of p = 160 ～ 3,800 torr. Using a lens of f (focal length) = 133 mm, the laser is irradiated into the gas, where the energy absorption is studied. If the laser is injected into the gas with the energy above a certain threshold for the breakdown, the rate of energy absorption is found to be ～ 17 percent of the incident energy at p > 760 torr. Injecting the laser into the SF₆-filled gap switch (gap length = 7 mm, p = 760 torr), we have studied the triggering characteristics. Excellent triggering characteristics were obtained; delay time for the discharge ～ 20 ns, and the jitter ～ 260 ps when the gap voltage is operated at 99 percent of the self-breakdown voltage. In addition, the triggering characteristics are studied by changing the focusing point axially. It is found that both the delay time and the jitter decrease when the focusing point tends to approach the high-voltage electrodes.     

Correlation between the hot plate ignition test and other laboratory-scale flammability tests on rubber conveyor belts with fabric skeletons

The hot plate ignition test was conducted on ten different conveyor rubber belts with fabric skeletons. In this test, a 25 × 25 mm² belt sample was placed on a stainless steel plate in an electric furnace and heated. The ‘ignition temperature’ was determined on each sample in almost the same way as proposed in Canada. The test results were compared with those from other laboratory-scale flammability tests (i.e. the small-scale flame tests, the Oxygen Index test and the laboratory-scale gallery test). The calculated results of both sample and rank correlation coefficients imply that the ‘10 signition temperature’ in this hot plate ignition test has a correlation with the results from both the Oxygen Index test and the laboratory-scale gallery test, but that it has very little or no correlation with those from the small-scale flame tests. On the other hand, it is found that the ‘60 s ignition temperature’ in this test has a far better correlation both with the results from the small-scale flame tests and with the time to ignition in the laboratory-scale gallery test than the ‘10 s ignition temperature’.     

A new approach to improve the high-voltage cyclic performance of Li-rich layered cathode material by electrochemical pre-treatment

Lithium-rich nickel–manganese–cobalt oxide, Li[Ni_0.17Li_0.2Co_0.07Mn_0.56]O₂, was prepared by a co-precipitation method, and its cyclic behavior at a high potential was investigated. The as-prepared material shows a rapid capacity fading in its initial several cycles when it was operated above 4.5 V, which could be significantly improved through a pre-cycling treatment. Its reversible capacity in the range of 4.8–2 V could be increased from 200 to 250 mAh g⁻¹ after 50 cycle through a stepped pre-cycling treatment.     

Packed Powder as Superleak for Spin Pump Experiments in Superfluid 3He A1

Experimental exploration of highly spin-polarized states of liquid ³He by applying external magnetic field is limited by the availability of static magnetic field. In the “ferromagnetic” superfluid A₁ phase of liquid ³He there is an alternate method for boosting spin-polarization by the process of spin pumping without requiring such high magnetic field. The spin pumping in the A₁ phase takes advantage of a superleak (SL) acting simultaneously as a filter for both entropy and spin. The spin pump technique that uses the SL-spin filter and a mechanical actuator enables us to directly boost polarization of ³He. The amount of enhancement of spin polarization has been limited so far. We are now developing a new type of SL filter made of packed aluminum oxide powder (referred as PAP-SL), in order to achieve greater enhancement of spin polarization. Several kinds of the PAP-SL filter were constructed by pressing aluminum oxide powders into a cylinder holder. The packed structures were carefully characterized by a flow-rate-measurement, X-ray tomography, and mercury intrusion porosimetry. The preliminary result shows that the PAP-SL works as SL filter for the superfluid ³He.