Evidence of VHE Gamma-Ray Emission from the Pulsar Nebula around PSR B1509-58

名古屋大学Nagoya University博士(理学)The gamma-ray pulsar PSR B1509-58 and its surrounding nebulas have been observed by using the 3.8m imaging Cerenkov telescope of the CANGAROO collaboration. The observations have been carried out during the years 1996 and 1997 in Woomera, South Australia at the gamma-ray threshold energies of 4 TeV and 1.5 TeV, respectivelly. Very high-energy gammarays-ray threshold in the 1997 data with 4.1significance. The estimated gamma-ray flrx is at energies above 1.5 Tev. On the other hand, it was possible only to set a 3 upper limit of above 4.0 TeV from the observations of 1996. No significant pulsation pulsation modulated with the pulsar ;eriod has been found in either the 1996 or the 1997 data. Our results when combined with X-ray observations lead to a value of the magnetic field strength consistent with equipartition value, in the X-ray nebula surrounding the pulsar. This field strength is much weaker than the one in the Crab nebula. This is the first evidence of VHE gamma-ray emission from a non-EGRET pulsar. It underscores the power of a new criterion for the search for VHE gamma-ray sources, i.e,. X-ray synchrotron nebulae driven by young rotation-powered pulsars.名古屋大学博士学位論文 学位の種類:博士(理学) (課程) 学位授与年月日:平成10年3月25日doctoral thesi

<総説>知覚判断の神経メカニズム

判断とは，複数の選択肢を一つに絞り込む審議のプロセスである。ヒトの判断は多様であるが，実際には共通するいくつかの原理がある。知覚判断の研究は，こうした判断の共通原理の神 経基盤の解明に大きく貢献した。本稿では，外界の動きや奥行きの判断に関わる神経系の計算原理 について解説する。知覚判断に関わる脳の情報処理は少なくとも2段階に分けられる。一つ目は， 外界の情報を脳内に忠実に再現する感覚情報処理系である。二つ目は，判断に必要な情報を収集し， 最適な行動が何であるかを計算する処理系である。この2 段階の処理は，判断の共通原理であると 考えられている。journal articl

Voltage Profi les on HV Distribution Lines with Various Network Confi gurations and Customers

Electrical power system reliability is a critical issue for utilities and power loss occurred in transmission and distribution network is a must consideration. Electrical distribution system is the largest portion of network in the electrical power system. There is voltage drop on long HV distribution line (D/L) due to heavy load consumption, absent of voltage regulation, as well as poor power factor collection on long HV D/L. Therefore, phase advancing capacitors (Shunt Capacitor, SCs) are installed in parallel with customer loads for voltage improvement and power factor correction. However, these SCs, sometimes, lead to Ferranti effect, especially at the very lightly loaded condition. Moreover, in recent years, the introduction of photovoltaic power generation systems (PV systems) into HV D/L has developed rapidly and may cause the unacceptable voltage variation on HV D/L. In this study, a virtual 6.6 kV long distance (20 km) HV D/L without PV system supported from Kyushu Electric Power Company (Qden) in Miyazaki branch, is introduced. In this long distance HV D/L, a 20 MVA transformer, three static voltage regulators (SVRs), and 50 customer loads are included. For very lightly loaded condition, the effects of SCs detachment area on the voltage profiles of HV D/L are numerically investigated and discussed. Moreover, the optimal location is proposed to change the suitable SVR for the purpose of upgrading voltage drop in heavy loaded condition. Then, voltage profiles of different lengths (20.3 km for long and 8.70 km for short) HV D/Ls with PV system installing SCs at customer’s side and different load capacity are discussed. Furthermore, the conditions of flowing line current on HV D/L with PV system for different load locations are explained with phasor diagram. A program based on the Newton Raphson method was coded for the power flow calculation.departmental bulletin pape

Intraarterial urokinase for thrombus migration after mechanical thrombectomy for large vessel ischemic stroke

[Background] Achieving rapid and complete reperfusion is the ultimate purpose for ischemic stroke with large vessel occlusion (LVO). Although mechanical thrombectomy (MT) had been a proverbially important procedure, medium vessel occlusion (MeVO) with thrombus migration can sporadically occur after MT. Moreover, the safe and effective approach for such had been unknown. We reported thrombolysis with intraarterial urokinase for MeVO with thrombus migration after MT. [Methods] We included 122 patients who were treated by MT with LVO stroke at our institution between April 2019 and March 2021. Of 26 patients (21.3%) who developed MeVO with thrombus migration after MT, 11 (9.0%) underwent additional MT (MT group) and 15 (12.3%) received intraarterial urokinase (UK group). The procedure time; angiographically modified Treatment in Cerebral Ischemia Scale (mTICI); functional independence, which was defined as modified Rankin Scale 0–2, on day 30 or upon discharge; and symptomatic and asymptomatic intracerebral hemorrhage (ICH) were compared between the UK and MT groups. [Results] The procedure time, mTICI, and asymptomatic ICH did not significantly differ between the groups. In the UK group, 8 of 15 (53.3%) patients obtained functional independence, and the functional independence rate was significantly higher in the UK group than in the MT group (p<0.05). Symptomatic ICH did not occur in the UK group, and its incidence was significantly smaller than that in the MT group (p<0.05). [Conclusion] The results of this study suggest that intraarterial urokinase for MeVO with thrombus migration after MT may safely improve angiographic reperfusion.journal articl

Dynamic I-V Characteristics of Schottky Diodes and PN Junction Diodes When Lightning Impulse Voltage Is Applied on Them

The purpose of this study is to assist the operation and maintenance of PV systems by studying the resistive conditions of bypass diode used in PV modules and to develop the diagnosis and on-line monitoring system for small and medium scale PV systems. This paper analyzes the breakdown and non-breakdown characteristics of Schottky diodes and PN Junction diodes by application of various ranges of voltages by Lightning surge simulator (LSS). In this study, we compare and discuss the numerical data of experimental results obtained under variable voltage applications of LSS are compared for both diodes on the resistive characteristics after breakdown, waveforms of voltage and current and the behaviors of dynamic curves. An applied voltage, on which the breakdown of diode takes place and dramatic change in I-V characteristics occurs, is called “critical voltage (Vc)”. From the study, it was observed that the magnitude of critical voltage (Vc) of PN junction diodes is higher than that of Schottky diodes in reverse direction although there is almost the same in forward direction. The authors are also probing that the possibility of more sensitive monitoring and diagnosis system for the resistive bypass diode in PV system based on numerical simulation results. The great difference of Vc is reflected for the dynamic relationship between voltage and current in reverse biasing for both diodes.departmental bulletin pape

Multivariate Analysis Using R for Various Climatic Effects on the Output Performances of CIGS and Multi-Crystalline Si Photovoltaic Systems Installed in Miyazaki, Japan

Generally, the performance of a PV system depends not only on its basic technical characteristics but also on the environmental conditions in which they will be set up. Therefore, studying the effects of climatic parameters such as solar irradiance on the plane of array (GPOA), ambient temperature (Ta), relative humidity (RH) and wind speed (νa) on the performance of PV is vital to be able to utilize efficiently solar energy. The authors have studied the effects of various climatic parameters on the output performances of the two PV systems, 60 kW Copper Indium Gallium Selenide (CIGS) and 50 kW Multi-Crystalline Silicon (MC-Si), which were installed within the campus of University of Miyazaki, Japan. The main objectives of the research are to improve the prediction of the PV systems performance while knowing the climatic parameters of a particular area in which they stand, and also provide a useful dataset for the comparative studies. The analyses were done by the multiple linear regression analysis (MLR) using the statistical software R. The performances of the two PV systems are in positive proportion to the GPOA and νa, however, as per the values of the slopes of the regression equations, the MC-Si PV system is smaller than the CIGS PV system, attributed to their different module tilt angles and elevations of the PV sites. The performances are in negative proportion to the Ta, but the more sensitivity can be observed in the MC-Si PV system. The RH negatively affected on the MC-Si PV system, although its positive effects can be observed in the CIGS PV system.departmental bulletin pape

The Mechanism of Flexible Work Arrangements on Work Engagement under COVID-19 : An Examination of the Mediated effect of Organizational Justice

departmental bulletin pape

Study on Propagation Characteristics of High Frequency Pulse Current in Electric Power Cable

The demand of reliable power systems and stability of electrical power supply are quite crucial for all of power companies. On the other hand, power systems installed during the period of high economic growth have been operating for over 30 years in Japan. For transmission and distribution lines, cross-linked polyethylene (XLPE) cable plays an important role in distributing the stable power to customers. Electric failure for the XLPE cable decreases year by year because of progress of manufacturing. However, at joint and terminal sections of the XLPE cable, partial discharges (PDs) occur in defects of insulating materials. The PD generation can occur at any points in the insulation system where electric field strength exceeds a PD inception electric field and can develop until breakdown occurs. That is, PDs which are owing to local electrical stress in the insulation or on the surface of the insulation reflect a kind of sign of insulation deterioration. Therefore, PD measurement is a useful technique of assessing the insulation deterioration of XLPE cables. In this study, the pulse propagation characteristics of a PD on actual 22kV XLPE cables were investigated.departmental bulletin pape

Study on Location Accuracy of Partial Discharge Locator for Electric Power Cable

For transmission and distribution lines, cross-linked polyethylene (XLPE) cable plays an important role in distributing the stable power to customers. Electric failure for the XLPE cable decreases year by year because of progress of manufacturing. However, at joint and terminal sections of the XLPE cable, partial discharges (PDs) occur in defects of insulating materials. The PD is a precursor to dielectric breakdown. Once PD occurs, it continuously erodes insulation material. The demand of reliable power systems is quite crucial for all of power companies, and then it is demanded to develop an on-line PD measurement technique and a monitoring system. In this study, we propose a PD locating system for XLPE cables in operation, in which the propagation velocity of PD current is not required for locating a PD. We first show how the locating system works on a XLPE cable network with time synchronization between two points. Additionally, the locating accuracy of the system is investigated.departmental bulletin pape

Partial Discharge Characteristics of XLPE Cable with Water Tree

Since the aging of electric facilities have become an important issue in Japan, safety of such facilities in operation and ensuring high reliability are highly demanded. It is also necessary for each electric power company to reduce the cost for maintaining, managing, operating, and updating facilities because of the electric power liberalization. For these backgrounds, some sorts of sophisticated technologies for on-line monitoring systems and deterioration diagnosis technologies are needed rapidly in order to avoid any electric failures. Our esearch is to develop partial discharge locator (PDL) which is to locate cable faults by detecting current pulses generated by partial discharges (PDs). This paper presented theoretical analysis of frequency characteristics of a PD pulse on a branch line for PDL adaptability of multiple branch lines by using a simulation software. In addition, as a comparison to the simulation, we also carried out experiments using actual XLPE cables and confirmed the integrity verification of the simulation results. In this paper, we investigated PD characteristics caused by water trees in XLPE cables. It was found out that PDs can be generated by water trees. Therefore, PDL can be used for locating water tree.departmental bulletin pape