Application of unified voltage analysis for high‐ and low‐voltage distribution systems by power flow calculation using indication method between nodes

It has been noted that the voltage of connection points rises according to the reverse power flow when grid‐connected photovoltaic systems are concentrated in distribution systems in residential areas. When this happens, the photovoltaic system may control the power generation output to maintain a suitable voltage for the connection point. Designing a demand area power system aiming at free access to a distributed power supply for energy‐effective practical use requires a precise understanding of this problem. When analyzing photovoltaic systems mainly connected to low‐voltage systems, we looked for a method of analysis in which the high‐voltage systems and the low‐voltage single‐phase three‐wire systems are unified. This report concerns use of the indication method between nodes using power flow calculation, for the purpose of developing a technique of analyzing unified high‐voltage systems and low‐voltage single‐phase three‐wire systems. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 147(3): 49–62, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10255     

Influence of Carbon Forms and Doped Elements in the Electrodes for the Production of Fullerenes

Production of fullereries using electrodes made of four kinds of pure carbon bearing materials and artificial graphite doped with seven kinds of elements such as B, Y, La, Gd, Ce, Pr and Nd have been examined. The yields of fullerenes were in a range between 12-20% of the soot produced for all pure carbon electrodes, even though the vaporization rate of amorphous carbon electrodes was about ten times higher than that of the natural graphite electrodes. However, for the doped graphite electrodes, the yield of fullerenes was less than 5%. From the above results it is concluded that fullerenes can be effectively produced with the pure carbon electrodes made of any form of carbon bearing materials used in this study and there is little material dependence on the yield of fullerences. Furthermore, the experiments using the artificaial graphite electrodes doped with metal elements suggests that the purity of the carbon electrodes affects the yeld of fullerenes greatly.     

Applications of wear-resistant thick films formed by physical vapor deposition processes

Several physical vapor deposition processes are being developed in Japan to obtain hard refractory carbide and nitride thick films. A good example is the process for producing TiC and/or TiN by (1) reactive evaporation, (2) reactive r.f. ion plating, (3) reactive sputtering, (4) activated reactive evaporation with a probe electrode and a grounded substrate or (5) activated reactive evaporation with a positive-biased or a.c. modulated substrate (low pressure plasma deposition, d.c. or a.c.). Thick films of chromium, chromium carbide and chromium nitride deposited on steel sheets by (6) a hollow cathode discharge process are being investigated for wear applications.This paper describes the examination of such films formed by processes (4)–(6). Wear resistance is correlated to microhardness, X-ray diffraction diagrams, scanning electron microscopy observations and scratch test results.TiC-coated WC-Co throw-away tool tips, for example, prepared in suitable deposition conditions show marked improvements: $\text{1}\text{20}$ to $\text{1}\text{30}$ on crater depth and $\text{1}\text{4}$ to $\text{1}\text{5}$ on flank wear compared with uncoated tips after 15 min of lathe machining a Ni-Cr-Mo steel SNCM-8 rod at a feed rate of 0.4 mm rev^-1, with a depth of cut of 0.5 mm and at a machining speed of 234-158 m min^-1. The hardness, color and crystal structure are reported for TiN-coated sheets.The features of chromium together with its carbide and nitride films deposited by a hollow cathode discharge process for wear applications are also described.     

Relation between fluidity and solvent extraction yield of coals

Four coals with similar ultimate analyses were Soxhlet-extracted with pyridine before and after heat treatment at 400 °C and with quinoline at 350 °C. Pyridine extraction yield tended to be proportional to log maximum fluidity (MF), but with some discrepancies. Quinoline extraction yield was more nearly proportional to log MF. However, the best correlation with log MF was obtained for quinoline extraction yield corrected for inert content.     

Preparation of cationic polystyrene latexes in the absence of emulsifiers

Preparation of cationic polystyrene latexes has been investigated in the absence of emulsifiers. It is clarified that a stable latex can be obtained by using 2,2′-azobis(2-amidinopropane) hydrochloride as initiator (initiator process). The latex seems to be stabilized with the fragments of the initiator chemically bound to the surface of particles. More stable latexes can be obtained by copolymerizing cationic monomers such as dialkyl aminoethyl methacrylates (copolymerization process). The stability of these latexes may predominantly be attributed to cationic monomers chemically bound to the surface of particles. Stable latexes with high solids content can be obtained by using the two-step polymerization technique in the copolymerization process. The particle formation process in the initiator process and the copolymerization process is discussed.     

A 0.65-ns, 72-kb ECL-CMOS RAM macro for a 1-Mb SRAM

An ultrahigh-speed 72-kb ECL-CMOS RAM macro for a 1-Mb SRAM with 0.65-ns address-access time, 0.80-ns write-pulse width, and 30.24-μm ² memory cells has been developed using 0.3-μm BiCMOS technology. Two key techniques for achieving ultrahigh speed are an ECL decoder/driver circuit with a BiCMOS inverter and a write-pulse generator with a replica memory cell. These circuit techniques can reduce access time and write-pulse width of the 72-kb RAM macro to 71% and 58% of those of RAM macros with conventional circuits. In order to reduce crosstalk noise for CMOS memory-cell arrays driven at extremely high speeds, a twisted bit-line structure with a normally on MOS equalizer is proposed. These techniques are especially useful for realizing ultrahigh-speed, high-density SRAM's, which have been used as cache and control storages in mainframe computers     

Polymers of α-substituted benzyl methacrylates as a new type of electron-beam resist

Summary Polymer of α-substituted benzyl methacrylate was found to be used as a new type of positive electron-beam resist, which forms methacrylic acid units in the polymer chain on the exposure to electron-beam and can be developed using alkaline solution as a developer. The sensitivity was dependent on the bulkiness of the ester group and the number of ?-hydrogen atoms in the ester group. The sensitivity and γ-value of atactic poly(α, α-dimethylbenzyl methacrylate) were improved by a factor of more than three over poly (methyl methacrylate).     

Formation of particles in the preparation of carboxylated polystyrene latexes

Carboxylated polystyrene latexes have been prepared by copolymerizing acrylic acid at the appropriate degree of neutralization in the absence or presence of sodium dodecyl sulfate (SDS), and the particle formation process was investigated from the number and uniformity of particles. In the absence of SDS or in a concentration range of SDS lower than 6.41 mmole/l., the formation of particles can predominantly be attributed to the precipitation of growing radicals formed in the aqueous phase; whereas in a concentration range of SDS higher than 6.41 mmole/l., the formation of particles can predominantly be attributed to the initiation of polymerization in the interior of SDS micelles containing solubilized styrene by the collision of growing radicals formed in the aqueous phase. In the former range, the number of particles increases linearly with increasing concentration of SDS below the critical concentration of 1.60 mmole/l., which is sufficient to stabilize particles formed by the precipitation of growing radicals, and remains constant above the critical concentration. The effect of initiator concentration as well as amount of styrene on the formation of particles also supports the particle formation process described above.     

Preparation of Pb(Zr,Ti)03 Through the Use of Cupferron

An organic chelation reagent, cupferron, was used to coprecipitate Ti⁴⁺ andZr⁴⁺. After the materials were fired, they were mixed with PbO powder and fired again at high temperatures to obtain Pb(Zr,Ti)0₃ (PZT). It was confirmed that this method is useful for the preparation of homogeneous PZT having no compositional fluctuations. No coexistence range of the tetragonal and rhombohedral phases was observed in the PZT compositions near the morphotropic phase boundary.     

Consideration of hepatic factor influence on drip infusion cholangiography

Review of experience at the Mayo Clinic with carotid bovine grafts in patients who undergo hemodialysis with a follow-up of of as long as 28 months revealed that the graft provides vascular access for hemodialysis when other vascular access sources have been exhausted. The graft is particularly helpful in the diabetic patient whose peripheral arteries have inadequate flow. The location in the thigh seems to be preferable to the forearm location. Clean puncture technique is important because infections usually mean graft loss and possibly severe complications, for example, hemorrhage or septicemia.