Power system stability enhancement by static var system using self-commutated inverters

This paper deals with static var compensators using self-commutated inverters (which is so-called SVG) compared with conventional SVC and Rotary Condenser. Improvement of power system stability is explained by using simple system model and checked by dynamic digital simulation. In the latter part of this paper, system outline, basic specifications and control diagram of the SVG rated 154 kV, ±80 MVA, which has been installed at INUYAMA Switching Station, are briefly presented. Field tests at INUYAMA verify that power swing is effectively damped and transmission capacity is increased.     

Effect of quenching,tempering, and cold rolling on creep deformation behavior of a tempered martensitic 9Cr-1W steel

The effect of quenching, tempering, cold-rolling, and aging treatments, which produce different dislocation substructures and different carbide distributions, on the creep-deformation behavior is investigated for a tempered martensitic 9Cr-1W steel at 873 K, mainly. The creep rate vs time curves indicate transient creep, where the creep rate decreases with time, and accelerating creep, where the creep rate increases with time. The minimum creep rate is closely correlated with the onset time of acceleration creep and is inversely proportional to the duration of the transient creep region. The onset of acceleration creep shifts to shorter times for the specimens subjected to the quenching, 20-hour tempering (long-term tempering) at 1023 K, and cold-rolling treatments than that for the specimen subjected to the standard quenching and tempering (QT) treatment. The onset of acceleration creep is closely correlated with the migration of lath or subgrain boundaries, causing the coarsening of laths or subgrains. Dislocation cells produced by cold rolling are free of M₂₃C₆ carbides. The migration and recovery of dislocation cells significantly promote the onset of acceleration creep. The preferential distribution of M₂₃C₆ carbides along lath boundaries is effective for the retardation of the onset of acceleration creep for up to longer times by the stabilization of lath boundaries. In the acceleration creep region, after reaching a minimum creep rate, the logarithm of the creep rate increases linearly with strain for a wide range of strains. The time to rupture (tr) is inversely proportional to the minimum creep rate times the acceleration of the creep rate (d ln /dε) in the acceleration creep region, but is not proportional to only the minimum creep rate, as given by

二维PIV图像处理算法

在二维PIV的图像处理中，本文从互相关技术出发，建立了相应的连续两幅图像之间的粒子对应方法，提出了误差对应速度向量的判断和消除准则。通过粒子的标定、粒子的对应、误对应粒子速度向量的判断和消除等步骤建立了相应的二维射流的PIV图像处理方法。利用日本可视化协会（VSJ）提供的二维射流标准图像的处理，可以发现本文建立的方法是切实可行的。     

An adaptive,error-free computation based on the 4×4 determinant method

The 4×4 determinant method makes it possible to unify geometric processing by the computations of 4×4 determinants composed of homogeneous coordinants vectors of four points or coefficient vectors of four plane equations. Because the method needs not require a division operation, error-free geometric computation is not difficult to realize by means of integer arithemtic of appropriate data length. The present paper proposes an error-free, efficient computing method, which computes the 4×4 determinants by adaptively selecting integer arithmetic of variable data length. This technique is discussed theoretically and experimentally.     

Synthesis of cationic surfactants with alkenyl group

Quaternary ammonium chlorides with long chain alkenyl groups were synthesized by the reaction of tert-amines with alkylallyl chloride which, in turn, were obtained by the allylic chlorination of 1-olefins with N-tert-butyl- or N-cyclohexyl-N-chloro-ethanesulfonamides. Of the two kinds of alkylallyl chlorides prepared by the allylic chlorination of 1-olefins, the γ-alkylallyl chlorides(I), were found to be reactive with tert-amines, while the secondary chlorides, α-alkylallyl chlorides(II), were not so reactive and, when the allylic chloride mixture was reacted with tert-amine under suitable reaction conditions, the γ-alkylallyl chloride could be selectively converted to a quaternary ammonium chloride while the α-alkylallyl chloride was recovered unreacted. The quaternary ammonium chlorides thus obtained were identified as γ-alkylallyl ammonium chlorides from their spectra, and they were shown to possess almost the same surface tension lowering ability as their saturated homologs, although larger critical micelle concentration values and greater water solubilities were observed.     

The surgical management of breast cancer, especially breast conserving treatment

The management of breast cancer is highly controversial. Various operations have been performed at different hospitals. Herein, we reviewed the results of randomized clinical trials regarding breast conserving treatment, and axillary and internal mammary lymph node dissections. Variations in local-regional therapy may not substantially affect survival, but the incidence of local-regional failure is inversely related to the extent of operation and/or radiotherapy. At present, surgeons are highly recommended to perform adequate surgery which provides the ultimate local control, does not compromise the chance for cure and gives the best cosmetic and aesthetic results. Therefore, quadrantectomy with or without immediate reconstruction, axillary dissection and internal mammary biopsy and breast irradiation are more preferably recommended for ensuring local control and for providing a better cosmetic and psychological impact.     

Direct Hydroxylation of Methyl Benzoate to Methyl Salicylate by Using New Pd Membrane Reactor

The direct hydroxylation of methyl benzoate was carried out using a newly developed Pd membrane reactor in which the active oxygen species is formed on the surface of Pd by the reaction between oxygen gas and the active hydrogen atoms that permeate through the Pd membrane from the opposite side. By using this Pd membrane reactor system, methyl salicylate showed a 4.7% yield at 423 K. The reaction mechanism was clarified based on the distribution of by-products.     

Creep and creep rate curves of a 10cr-30mn austenitic steel during carbide precipitation

The effect of carbide precipitation on creep and creep rate curves was investigated for 10Cr-30Mn austenitic steel containing 0.003 to 0.55 wt pct carbon. After solution annealing, the specimens were subjected to creep testing at 873 K for up to 30 Ms (8300 hours). In the low-carbon steels containing below 0.1 wt pct carbon, where carbide precipitation scarcely occurred, the decrease in creep rate with time in the transient creep region was described by log έ = A - (1/3) log t, where A is a constant depending on stress and carbon concentration. On the other hand, in the high-carbon steels containing above 0.2 wt pct carbon, where extensive precipitation of M₂₃C₆ occurred, the creep rate decreased significantly at long times above 3 to 5 ks (1 hour), deviating from the preceding equation for the low-carbon steels. The Johnson-Mehl equation with the time exponent n = 2/3 provided a reasonable approximation for the significant decrease in creep rate at long times. This resulted from a stress-induced precipitation of M₂₃C₆ on dislocation lines produced by creep deformation. The rate constant of the Johnson-Mehl equation depended on carbon concentration but not on stress levels examined.     

A Study of High-Definition TV System in the Future

The results of our studies of high-definition television system are described concerning picture quality, signal standard and transmission system.