Transient stability limit issues at three-phase short-circuit in parallel running of both a superconducting generator and a conventional one

Experimental studies using20-kVA superconducting generators (SCG) have been performed in an attempt to understand some of the characteristics of SCG in power systems. It is necessary to investigate the characteristics for the parallel operations of both an SCG and a conventional generator (CG) when an SCG is installed in a present power station. Some of the results of the authors' studies on parallel running of the 20-kVA SCG and the 20-kVA CG are described in this paper. In the experimental system, the SCG is connected to a regional power system (infinite bus) through reactors (artificial transmission lines) and the CG is connected to the terminal of the SCG. Using experiments and computer simulations, the transient characteristics at three-phase short-circuit faults are investigated: 1) when the CG is not disconnected; and 2) when the CG is disconnected after reclosing the line with the fault cleared. Two kinds of stable limit curves are obtained for output power at three-phase short-circuit fault for the aforementioned two cases.     

Primary Sj?gren's syndrome followed by chronic myelogenous leukemia: a case report with a ten year history

We describe a female patient with primary Sj?gren's syndrome who subsequently developed chronic myelogenous leukemia. The patient received a bone marrow transplant (BMT) from a genotypically HLA-identical brother after pre-transplant preparation with busulfan and cyclophosphamide. Eighteen weeks later, cutaneous and mucosal chronic graft-versus-host disease developed, followed by death 11 months after transplantation. Anti-Ro/SS-A antibodies disappeared within 6 months post-BMT, but antinuclear antibodies remained positive through the post-transplant course.     

Crystallization and preliminary X-ray analysis of a truncated family A alkaline endoglucanase isolated from Bacillus sp. KSM-635

The catalytic domain of an alkaline endo-1,4-beta-glucanase (family A) isolated from Bacillus sp. KSM-635 (Mr = 40.2 kDa) was crystallized using the hanging drop vapor diffusion method. Two different crystal forms were obtained. Form 2 crystals (trigonal space group R3 with cell dimensions of a = b = 111.9 and c = 207.1 angstroms in a hexagonal lattice) were found to be more stable than form 1 ones upon X-ray irradiation. A full data set for form 2 crystals has been collected up to 3.3 angstroms resolution.     

A triazine dye, cibacron blue F3GA, decreases oxacillin resistance levels in methicillin-resistant Staphylococcus aureus

Cibacron blue F3GA (CB) was found to reduce the MIC of oxacillin for methicillin-resistant Staphylococcus aureus (MRSA). This effect was not observed with methicillin-susceptible S. aureus. CB alters the resistance level of MRSA through a factor(s) other than mecA-related products, major autolysins, or femAB products. The exact target(s) of CB in causing the effect is unknown.     

The heat resistance of silicon dioxide-base fiber thermal insulation

Conclusions The high heat resistance of amorphous fiber high-silica materials is shown. The presence of the crystalline phase (cristobalite) decreases their heat resistance.The critical temperature range (200–250°C) in which intense crack formation and failure of fiber high-silica thermal insulation materials containing cristobalite occurs is established.Translated from Ogneupory, No. 4, 53–55, April, 1987.     

High-frequency multiple diffraction by a flat strip: Higher order asymptotics

By including correction terms in inverse powers of the wavenumberk, one may hope to extend the range of applicability of multiple edge diffracted geometrical theory of diffraction (GTD) to lower frequencies, and also to extend thereby the range of validity of the corresponding time domain solutions. The correction can be applied to each of the surface rays in the hierarchy that has been proposed by us recently as a model for multiple interaction between parallel edges separated by a plane surface segment on a two-dimensional perfectly conducting scatterer. The surface rays, which were found to explain the structure of the complex resonances in transient scattering, are excited for each interaction by equivalent line sources, dipole line sources, and their derivatives, with strengths determined from the asymptotic expansion of the edge diffracted field. This procedure is applied in detail toE- andH- polarized plane wave scattering by a perfectly conducting flat strip, up to quadruple diffraction, including consistentO(k^{-2})corrections with respect to the dominant term. The procedure is applied also to generate corrected multiple diffracted individual surface ray fields, which lead to an improved equation for the complex resonances in the "layer" synthesized in the complex frequency plane by a surface ray of a particular order. Inclusion of the low frequency corrections reduces further the already small discrepancy between the ray optically calculated low frequency resonances and those computed numerically by the moment method.     

Analysis of cases allowed to cease erythromycin therapy for diffuse panbronchiolitis--comparative study between patients with cessation of the therapy and patients continuing the therapy

We investigated the effect of erythromycin (EM) in patients with diffuse panbronchiolitis (DPB) who were divided into 2 groups, the short term group with 8 patients who were treated for at least 2 years and the long term group with 7 patients who were treated for more than 3 years. Each mean value of %VC, FEV1.0, FEV1.0% and PaO2 two years after administration to these patients was improved than before administration of EM, with the exception of PaO2 in the long term group. There was no change in %VC, FEV1.0, FEV1.0% or PaO2 in each group between one year after the therapy and thereafter, with the exception of the fact that FEV1.0% in the short term group, except patients restarting EM therapy, 2 years after the therapy was significantly higher than in the long term group. One patient was readministered EM because of recurrence of DPB after cessation of EM therapy, whose %VC, FEV1.0 and PaO2, but not FEV1.0%, one year after the therapy were increased in those before the therapy. The Neutrophil proportion in the bronchoalveolar lavage (BAL) fluid in this patient was still high after the therapy (94.5%), while that in the patients with cessation of the therapy was improved to the level of less than 8%. Neutrophil proportion in BAL fluids in the patients with continuation of the therapy revealed a high or low level after the therapy. These results suggest that the patients, whose %VC, FEB1.0% and PaO2 were improved and whose proportion of neutrophils in BAL fluid reduced to a normal level compared with those before EM therapy, can be allowed to cease therapy after 2 years or more of EM therapy.     

The effect of beam profile at a focal point on welding deformation. A study of the deformation behaviour by laser welding at micron or submicron level in automobile parts

Due to a growing awareness for the environment, demands for functions which enable cleaner exhaust emissions and lower fuel consumption have increased in the field of automotive components. In order to manufacture automotive components that meet these demands and still remain competitive, it is vital to develop high-precision processing technologies for realising new functions. One technique which has been receiving attention is laser processing.^1,2 Laser welding has a higher energy density and hence induces much less welding deformation than arc welding. However, even this degree of deformation is too significant to ignore in welding at micron and sub-micron levels (which is the subject of this study). Also, since the types of lasers used in laser welding vary greatly, an understanding of the characteristics between laser energy distribution (the beam profile) and welding deformation is necessary to improve precision in processing. For example, by examining the effects of different beam profiles at the focal point on welding deformation, it will be possible to obtain a beam profile and enable the reduction and control of welding deformation at the sub-micron level.     

Transovarian transmission of a foreign gene in the silkworm, Bombyx mori, by Autographa californica nuclear polyhedrosis virus

We introduced a firefly luciferase gene, expressed under control of Drosophila heat shock protein gene promoter, into Autographa californica nuclear polyhedrosis virus (AcNPV). When the 5th instar larvae of the silkworm, Bombyx mori, were inoculated with the recombinant virus, luciferase activities were detected in the virus-infected larvae and pupae, and in the newly hatched larvae of the next generation. PCR amplification and Southern blot hybridization analysis demonstrated that the luciferase gene was transmitted through at least the F2 generation. In addition, the V-cathepsin gene, encoding a cysteine protease of AcNPV, was also detected in the DNA of all individuals of the F2 generation. These results show that AcNPV can be utilized as vector for the transovarian transmission of foreign genes in the silkworm.