Space charge behavior in an antistatic polymer including polymer solid electrolyte

A polymer dielectric material tends to be easily charged and may cause an electrostatic discharge, due to the serious problems that result when consequent electromagnetic noise damages the electronic circuits in various kinds of apparatus. The antistatic polymers that have been developed to prevent electrostatic discharge contain polymer solid electrolytes so that space charge originally exists inside them. The mechanism of the antistatic discharge effect of the polymer has been investigated by measuring the space charge distribution using the high-resolution pulsed-electroacoustic method. The experimental results suggest that the internal space charge of the polymer accumulates at the surface and forms heterocharge distribution at the interface between the electrodes and the specimen. Thus, internal space charge compensates the applied electric field, resulting in preventing the increase of the surface potential. In addition, internal space charge behavior relates to the dispersion condition of the polymer solid electrolyte that depends on the quantity of the electrolytes and the specimen procedures.     

Spherical silicon solar cell with reflector cup fabricated by decompression dropping method

A spherical Si solar cell with a reflector cup was successfully fabricated by a dropping method at decompression state. In the dropping method, melted Si droplets were instilled at decompression state (0.5× 105Pa) to reduce crystal growth rate, dominating crystal quality such as dislocation density in crystal grains. Spherical Si solar cells were fabricated using the spherical Si crystals with a diameter of 1 mm and then mounted on a reflector cup. The current-voltage measurement of the solar cell shows an energy conversion efficiency of 11.1% (short-circuit current density ( Jsc ):24.7 mA·cm-2,open-circuit voltage: 601 mV, fill factor:74.6%). Minority carrier diffusion length determined by surface photovoltage method was 98 μm. This value can be enhanced by the improvement of crystal quality of spherical Si crystals. These results demonstrate that spherical Si crystals fabricated by the dropping method has a great potential for substrate material of high-efficiency and low-cost solar cells.     

Sodium pump distribution is not reversed in the DBA/2FG-pcy, polycystic kidney disease model mouse

Recently, it has been reported that Na,K-ATPase in the renal epithelia of human autosomal dominant polycystic kidney disease and cpk mouse, a murine model of autosomal recessive polycystic kidney disease, mislocates to apical plasma membrane and that mislocated Na,K-ATPase causes the cyst formation. Whether the DBA/2FG-pcy mice, which are presumably a suitable model for autosomal dominant polycystic kidney disease, also exhibit the reversal polarity of Na,K-ATPase localization was examined. Kidneys of newborn DBA/2FG-pcy mice, and those at early and late stages of cyst development were examined by immunohistochemical techniques. At any stage, abnormal distribution of Na,K-ATPase on the apical membranes of tubular epithelial cells could not be detected. It is suggested that cysts can be formed without reversed polarity of Na,K-ATPase distribution in pcy mice.     

Estimating power-frequency characteristics in power systems by means of spectral analysis techniques

This paper shows that normal power system operating data may be used to determine the power-frequency characteristics in power systems. Data are processed as random signals using spectral analysis techniques, and the results estimate the generator and load power-frequency characteristics as transfer functions. The generator characteristics K_g are determined as a transfer function of the system in which input signals are frequency fluctuation ΔF and generator power setting signal ΔP_g, and output signal is generator power output ΔP_e, To estimate the load characteristics K_l, a difficulty arises. There is a relation ΔP_/ = ΔL_o + K_lΔF between actual load ΔP_l, ideal load under the state of nominal frequency ΔL_o, and fluctuation of system frequency ΔF. Because it is impossible to measure ΔL_o directly, ΔL_o and K_lΔF cannot be separated. With regard to a partial system, when its capacity is small enough compared with the total system capacity, the contribution of ΔL_o in a partial system to ΔF of the total system may be ignored, that is, ΔF and ΔL_o are considered as independent phenomena. Thus the cross spectrum of ΔF and ΔL_o decreases to zero according to the increase of data in number, and K_l of the partial system can be estimated.     

A simple method for purification of adult pig pancreatic endocrine cells

Adult pig pancreatic endocrine cells were harvested by autodigestion without added enzymes. The isolated, crude cells were purified by mono-poly resolving medium (MPRM). The purity of the harvested cells was determined by dithizone staining and the number of pancreatic endocrine cells was counted. A large number of the cells were stained red with dithizone and showed a high viability and a good insulin secretory response to glucose stimulation. The average number of cells purified by MPRM was 3.40 +/- 1.32 x 10(5) cells/g pancreas and the number of dithizone-stained cells was 2.81 +/- 1.09 x 10(5) cells/g pancreas. The insulin secretion from the pancreatic endocrine cells was maintained throughout a 40-day observation period and high glucose stimulation induced an increase in insulin secretion from the cultured cells. In the cells purified by MPRM, light and electron microscopic studies showed the cells to be typical pancreatic endocrine cells. The present purification method using MPRM allowed us quickly to obtain a large amount of adult pig pancreatic endocrine cells from the unpurified preparations. It is thought to be useful for transplantation and biochemical or biological studies of adult pig pancreatic endocrine cells.     

Mechanical properties of poly(vinyl chloride)-poly(acrylonitrile-co-butadiene) blends with modulated structure

By solution-casting we prepared poly(vinyl chloride)-poly(acrylonitrile-co-butadiene) blends with a modulated structure (a co-continuous two-phase structure with periodic distance of a few micrometres or less). Mechanical properties of the film specimens were investigated by the uniaxial tensile test combined with small-angle light scattering. A 50: 50 plastic-rubber blend has a high initial modulus which is close to that of the rigid plastic. Nevertheless, it can deform to a large extension ratio up to 6. It cannot immediately recover to its original length after the stress-strain test, i.e. residual strain in the stress-strain curve persists. However, after release from the instrument the film gradually shrinks to its original length at room temperature. After strain recovery the film shows a stress-strain curve almost identical to the original. It seems that the stretched film healed simply by resting at room temperature. Based on the light-scattering studies, a helical spring model is derived for the two-phase system with modulated structure, exhibiting the characteristic mechanical properties mentioned above. The spring model interprets well the dependence of Young's modulus on the blend composition and the periodic distance of the modulated structure.     

An evaluation method of PV systems

Data evaluation methods have wide adaptations, such as feedbacks to PV system operation management and design. The authors have already developed sophisticated verification method (SV method) of PV systems, which is a simple evaluation method to identify six kinds of system loss rates using basic information and simple four measurable data. This time, the authors introduced quality diagnosis to our previous model for compensating the measurement errors in field data, and improved the algorithm of the model. Consequently, validity of the evaluation result became better than the previous model.     

A novel method of examining carbonaceous deposits on spent catalyst surfaces

Xenon ion-bombardment used in conjunction with Auger electron spectroscopy was able to discriminate two types of carbonaceous materials accumulated on the surfaces of iron oxide and rhenium/iron-oxide catalysts spent for CO hydrogenation at 250°C and 2.1 MPa. One of the carbonaceous materials was easily eliminated from the surfaces by ion bombardment or by heat-treatment in vacuo at 150°C. On iron oxide only this “soft” carbonaceous material was present. On rhenium/iron oxide, bombardment-resistant “hard” carbonaceous material was also found. The presence of this hard carbonaceous material had little effect on the level of CO hydrogenation activity or the deactivation behavior of this catalytic system.     

Analysis of irregular increase in sheet resistance of Ni silicides on transition from NiSi to NiSi2

The annealing conditions causing an irregular peak in sheet resistance of nickel silicides are investigated. It is found that the irregular rise in sheet resistance occurs at a critical temperature of 750-775 °C as a result of agglomeration related to phase transition from NiSi to NiSi₂. Experiments on the effect of temperature, heating rate and annealing duration in rapid thermal annealing revealed that the high-resistance state produced by annealing at the critical temperature could not be changed by subsequent annealing at higher temperature, and that the high-resistance state required 30-40 s at the critical temperature to form. Pre-annealing at 600 °C was found to suppress the later formation of the high-resistance state.