Cortical blood flow response to hypercapnia during anaesthesia in Moyamoya disease

Cortical blood flow (CoBF) was measured continuously by the laser-Doppler method to evaluate the effect of hypercapnia on cortical blood flow during ten surgical procedures in ten young patients (mean +/- SD 9.3 +/- 6.4 yr) with Moyamoya disease. The CoBF was 42.8 +/- 13.4 (ml.100 g-1.min-1) during normocapnia (PaCO2 = 39.0 +/- 2.4 mmHg), and 38.7 +/- 14.4 during hypercapnia (PaCO2 = 47.1 +/- 2.5 mmHg). There was a decrease in CoBF with hypercapnia (P < 0.05) so that the normal CoBF response to hypercapnia was impaired during surgery in the patients with Moyamoya disease. He concluded that patients with Moyamoya disease have a precarious cerebral circulation and hypercapnia may be detrimental to the cortical circulation. This suggests that normocapnia is preferable to hypercapnia in patients with Moyamoya disease during anaesthesia.     

Study of molecular behavior in oxidation of insulating oil using terahertz spectroscopy

The stock of aged power equipment is increasing and it is important to clarify the characteristics of deteriorated insulating oil. This paper describes a basic study of molecular behavior in the oxidation of insulating oil by terahertz spectroscopy. The oxidation of insulating oil was modeled by using various compositions of dodecane and 2‐octanol. The terahertz measurements indicated that signi?cant absorption related to hydroxyl groups (‐OH) occurred between 6 and 7 THz. The absorption band was also observed in accelerated aging alkylbenzene, which is used in power equipment as insulating oil and is sensitive to hydrogen bonds. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 183(1): 9–15, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22335     

A Basic Study of User Utility Maximizing Content Retrieval from Information Networks

This paper proposes some basic methods of content search yielding high user utility or user's satisfaction from numerous information sources scattered over large‐scale networks. In these methods, the search policy is decided by the estimated user utility gain and/or current user utility for each search action, and the most favorable combination of information sources and search content items is selected so as to enlarge the total user utility of the entire search activity. In addition, we evaluate the efficiency of the methods by computer simulations, in which we specify the network topology, user utility functions, probabilities of existence of the search content items in each information source, and so on, apply the proposed methods and other methods for comparison, and compare their aggregate utility gains as an estimation index. The proposed methods are found to achieve good performance in general and an index value about 2.45 times that of ordinary search is observed in an extreme simulation scenario. We discuss the pros and cons of the proposed methods for all the simulation scenarios.     

基于4次线性微分方程的雷电冲击试验波形分析

当冲击试验电压高时,冲击试验电压的波形叠加过冲和振荡。这是由于冲击试验回路的残余电感、被试设备的大杂散电容或二者共同作用产生的。文章用4次微分方程式对振荡冲击试验的等值回路进行了分析,结果表明,波形可分为非振荡波头、振荡波头、非极性反转波尾、非振荡的极性反转波尾和振荡极性反转波尾5个部分。非振荡的极性反转波尾和振荡极性反转波尾的产生原理是不同的。波形的高频分量定义为振荡波形,非振荡波形是不含振荡波形成份的波形。文章的研究结果是后者的产生原因和等值电阻、等值电感的关系以及4次方程的根有关。文章给出了它们之间的关系。     

Frequency of Upward Lightning Hits to Wind Turbines in Winter

In recent years, frequent damage to wind turbines by winter lightning has been reported in the region along the Sea of Japan. It is a serious finding that lightning hits concentrate on wind turbines in this region. The authors investigated the increase rate of the frequency of lightning hits on wind turbines due to wind turbine construction by using LLS (lightning location system) data. As a result, an experimental formula to estimate the increase rate of the frequency of lightning hits on wind turbines as a function of parameters related to the construction conditions, namely the height of wind turbines, the height above sea level, and the latitude, is proposed.     

Effects of cononsolvency on gelation of poly(vinyl alcohol) in mixed solvents of dimethyl sulfoxide and water

We studied the rates of gelation and phase separation of poly(vinyl alcohol) (PVA) solutions in mixtures of dimethyl sulfoxide (DMSO) and water at 25 °C and found that both the rates show a maximum at a volume fraction of DMSO φ_DMSO=0.60 while gelation was not observed either in pure DMSO or pure water, suggesting that water-DMSO is a cononsolvent system for PVA. On the basis of the data by Cowie [Can J Chem 36 (1961) 2240] we concluded that the 1:2 stable complex between one DMSO molecule and two water molecules is the main cause of this cononsolvency.     

Fabrication of vertically aligned single-walled carbon nanotubes in atmospheric pressure non-thermal plasma CVD

A fabrication technique of high-purity vertically aligned single-walled carbon nanotubes (VA-SWCNTs) using atmospheric pressure plasma enhanced chemical vapor deposition is presented. Although densely mono-dispersed Fe-Co catalysts of a few nanometers is primarily responsible for VA-SWCNT growth, carbon precipitation was virtually absent in the thermal CVD regime at 700 °C. On the other hand, high-purity VA-SWCNTs without measurable defects were grown at 4 μm min⁻¹ by applying atmospheric pressure radio-frequency discharge (APRFD) which has been previously developed for this purpose. The results proved that cathodic ion sheath adjacent to the substrates, where a large potential drop exists, also plays an essential role for the controlled growth of SWCNTs, while ion damage to the VA-SWCNTs is inherently avoided due to high collision frequency among molecules in atmospheric pressure. Operation regime of APRFD and tentative reaction mechanisms for VA-SWCNT growth are discussed along with optical emission spectroscopy of near substrate region.