A study of generator system selection for large wind turbine generator system

This paper focuses on selection of wind turbine generation systems that include generators, converters, and gears. We study three systems: a permanent magnet generator (PMG) system, a doubly‐fed generator (DFG) system, and a synchronous generator (SYG) system in terms of the system efficiencies and running costs. The system efficiencies and running costs are calculated by considering the relationship between wind power and wind conditions. According to these results, the one‐step gear PMG system is the best choice for a large wind turbine system. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(1): 51–57, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20506     

Use of mammalian target of rapamycin inhibitors after failure of tyrosine kinase inhibitors in patients with metastatic renal cell carcinoma undergoing hemodialysis: A single‐center experience with four cases

We retrospectively identified patients with end‐stage renal disease undergoing hemodialysis treated with the mammalian target of rapamycin inhibitors as a second‐ and/or third‐line targeted therapy after treatment failure with the tyrosine kinase inhibitors for metastatic renal cell carcinoma. Patient medical records were reviewed to evaluate the response to therapies and treatment‐related toxicities. Four patients were identified. All patients had undergone nephrectomy, and one had received immunotherapy before targeted therapy. Two patients had clear cell histology, and the other two had papillary histology. All patients were classified into the intermediate risk group according to the Memorial Sloan‐Kettering Cancer Center risk model. All patients were treated with everolimus as a second‐ or third‐line therapy, and two patients were treated with temsirolimus as a second‐ or third‐line therapy after treatment failure with sorafenib or sunitinib. The median duration of everolimus therapy was 6.7 months, whereas that of temsirolimus was 9.5 months. All patients had stable disease as the best response during each period of therapy. There were no severe adverse events. The use of mammalian target of rapamycin inhibitors in patients who previously failed to respond to tyrosine kinase inhibitors appears to be feasible in patients with end‐stage renal disease requiring hemodialysis.     

Expression of tropomyosin alpha 4 chain is increased in esophageal squamous cell carcinoma as evidenced by proteomic profiling by two-dimensional electrophoresis and liquid chromatography-mass spectrometry/mass spectrometry

To identify proteins associated with esophageal carcinogenesis, we performed protein profiling of 16 esophageal squamous cell carcinomas (ESCCs) and paired noncancerous tissues by 2-DE and MS/MS. In cancerous tissues, three spots showed significant up-regulation in the amount of protein, while eight spots were significantly down-regulated. The identities of the spots were determined by PMF with LC-MS/MS and were confirmed by immunoblotting. The up-regulated proteins were tropomyosin alpha 4 chain, transgelin, and pyruvate kinase. The down-regulated proteins were serum albumin precursor, isoforms of annexin A1, tropomyosin beta chain, 14-3-3 protein sigma, and isoforms of serotransferrin precursor. In all 16 cases, up-regulation of the tropomyosin alpha 4 chain was confirmed by immunoblotting. Localization of the tropomyosin alpha 4 chain in ESCC cells and adjacent fibroblasts was confirmed by immunohistochemistry.     

Cooperative control of multiple neural networks for an indoor blimp robot

We report on the cooperative control of multiple neural networks for an indoor blimp robot. In our research group, the indoor blimp robot has been studied to achieve various flying robot applications. The objective of this article is to propose a robust controller that can adapt to mechanical accidents such as the breakdown of propellers. In our proposed method, each propeller thrust is independently calculated by a small neural network. We confirm the advantage of the proposed method against the control by a single large neural network. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Endothelium-dependent vasodilator effects of the extract from Salviae Miltiorrhizae radix. A study on the identification of lithospermic acid B in the extracts

1. The aqueous extract of Salviae Miltiorrhizae radix (Chinese crude drug named "dan-shen") relaxed the noradrenaline-precontracted aorta with endothelium. 2. Vasodilation by the extract disappeared in aorta without endothelium, and was inhibited by pretreatment with 10(-4) M NG-monomethyl-L-arginine (L-NMMA) or 10(-5) M methylene blue. 3. The inhibition of the extract-induced vasodilation by L-NMMA was reversed by L-arginine (3 x 10(-4) M). 4. The component of the extract was analyzed by chromatography, fast atom bombardment mass spectroscopy (FAB-MS) and 1H-NMR. 5. An active component of the extract, which showed endothelium-dependent vasodilation, was found to be identical with lithospermic acid B.     

Development of a three-phase unbalanced voltage fluctuation compensating system using a self-commutated static var compensator

This paper describes a self-commutated static var compensator for suppressing voltage fluctuations caused by an ac electric railway (Shinkansen, or new trunk line). The ac electric railway is a single-phase load with large changes of reactive power and it causes large voltage fluctuations and power imbalances among the three phases in the power system. The authors have developed a new voltage fluctuation compensating system using a self-commutated static var compensator. This system has the functions of reactive power compensation and negative-phase-sequence current absorption. It can suppress rapidly changing voltage fluctuations and reduce the three-phase power imbalance caused by the ac electric railway effectively. This compensating system, with a capacity of 40 MVA, was put to practical use for the first time in the world in 1993. The test results at the site show that the system has excellent performance characteristics. A theoretical analysis of the characteristics of voltage fluctuations with or without the compensating system and an evaluation of test results, including a comparison between the theoretical and measured values, are also reported. © 1998 Scripta Technica, Inc. Electr Eng Jpn, 121(3): 67–78, 1997     

Measurement of space charge distribution in epoxy resin

Internal space charge behavior of insulating materials has recently attracted attention of many researchers, and a large number of experimental studies were carried out by using the materials for dc cables, such as XLPE, LDPE, and HDPE. Epoxy resins are used for insulation under strong electric fields in power apparatus and in electronic devices, and we investigated the behavior of internal space charge using the pulsed electroacoustic method. Two types of epoxy resins were studied: insulation-grade and craft-grade. When dc electric fields were applied to the craft resins treated by immersing them into room-temperature water for 8 and 24 h, positive and negative charges accumulated near the anode and the cathode, respectively, and the charge distribution changed with the immersion time. On the other hand, no charge was observed in the insulation-grade epoxy resin. Next, we treated the samples by immersing them into 100 °C water for 8 h. When the sample was treated for 8 h, hetero charge distribution, which means positive charges near the cathode and negative charges near the anode, was observed. This result is consistent with a previous paper reporting that by chemical analysis, secondary decomposition had occurred. These results show that water and temperature influence the internal space charge behavior of epoxy resins. © 1999 Scripta Technica, Electr Eng Jpn, 129(3): 9–16, 1999     

Effect of Crystal Grain Size and Thermal Stress on Martensitic Transformation of Phosphorus-Bearing Dicalcium Silicates

A series of P₂O₅-bearing Ca₂SiO₄ solid solutions, (Ca_{2- x /2}open square _{x /2})(Si_{1- x} P _x )O₄ with x = 0.02 and 0.06 lessthan equal to 0.11, was prepared. The alpha´_L <–> ß martensitic transformation temperatures were determined by high-temperature XRD for powder specimens with x = 0.02. With decreasing particle size, both M _s and M _f decreased, while both A _s and A _f were almost unchanged. Each transformation temperature was lower than that of pure Ca₂SiO₄. The phase composition at 25°C for the crystals with 0.075 lessthan equal to x lessthan equal to 0.10 was dependent not only on the x -value but also on the particle size and the intensity of the thermal stress upon quenching. The effect of the latter two was most clearly recognized in the phase composition of the crystals with x = 0.09. The phase composition was changed between the two extremes; one was composed of 8% alpha´_L-phase and 92%ß-phase and the other was 96% alpha´_L-phase and 4%ß-phase. For the crystals with 0.06 lessthan equal to x lessthan equal to 0.065 (ß-phase) and 0.105 lessthan equal to x lessthan equal to 0.11 (alpha´_L-phase), only the x -value governed the phase composition.     

Sesame seed and its lignans produce marked enhancement of vitamin E activity in rats fed a low α-tocopherol diet

Three series of experiments demonstrated that sesame seed and its lignans cause significant elevation of α-tocopherol content in rats. In Experiment 1, 20% sesame seed (with a negligible amount of α-tocopherol) supplementing 10 (low), 50 (normal), or 250 (high) mg/kg α-tocopherol diets (protein and fat concentrations in diets were adjusted to 200 and 110 g/kg, respectively) all caused a significant increase of α-tocopherol in the blood and tissue of rats. In Experiment 2, groups of rats were fed five different diets: a vitamin E-free control diet, a low α-tocopherol diet, and three low α-tocopherol diets supplemented with 5, 10, and 15% sesame seed. Changes in lipid peroxides in liver, red blood cell hemolysis, and pyruvate kinase activity, as indices of vitamin E deficiency, were examined. These indices were high in the low α-tocopherol diet, whereas supplementation with even 5% sesame seed suppressed these indices completely and caused a significant increase of α-tocopherol content in the plasma and liver. In Experiment 3 two diets containing sesame lignan (sesaminol or sesamin) and low α-tocopherol were tested. Results in both of the sesame lignan-fed groups were comparable to those observed in the sesame seed-fed groups as shown in Experiment 2. These experiments indicate that sesame seed lignans enhance vitamin E activity in rats fed a low α-tocopherol diet and cause a marked increase in α-tocopherol concentration in the blood and tissue of rats fed an α-tocopherol-containing diet with sesame seed or its lignans.     

Preparation of highly acidic hydrated niobium oxide

In order to obtain a highly acidic hydrated niobium oxide, the preparation methods and conditions such as niobium precursors, precipitating reagents, treatment of precipitates, washing of precipitates, final pH in precipitation, and calcination temperature were systematically examined. Strong acidic sites of H₀−8.2 were found to appear on hydrated niobium oxide when the oxide was prepared by boiling the precipitates, which were obtained by hydrolysis of niobium oxalate with KOH, in a diluted mild acid solution(preferably 0.1N HNO₃) followed by washing with hot water several times and heating in air at 300 °C. Final pH in the precipitation must be below 11.