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精确测量的地幔体波走时及地幔非均匀性的强度(英文) 被引量:9
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作者 akira yamada Yuhei OHTA 《地学前缘》 EI CAS CSCD 北大核心 2006年第2期37-47,共11页
用波形相关法精确地测定了在世界各地发生的87个6级以上地震的P波, PP波和Pdiff波的503个走时数据。记录这些地震波形的是新建于西太平洋地区的海洋半球地震观测网。我们利用这些高精度的走时数据研究了地幔体波的走时残差的范围及地幔... 用波形相关法精确地测定了在世界各地发生的87个6级以上地震的P波, PP波和Pdiff波的503个走时数据。记录这些地震波形的是新建于西太平洋地区的海洋半球地震观测网。我们利用这些高精度的走时数据研究了地幔体波的走时残差的范围及地幔非均匀性的强度。结果表明,P波、PP波和Pdiff波的走时残差最大分别为9 s ,11 s和15 s ,这为地幔层析成像反演中应该使用的体波走时残差数据的范围提供了重要信息。超出这一范围的走时残差数据不应该用于反演中,以免歪曲成像结果。我们发现,当震中距小于40°时,P波走时残差的范围为-6到+9 s。而对于40°到99°之间的震中距,P波走时残差的范围为-3到+5s。由于震中距越大,P波穿透地幔越深,我们这一结果提供了直接和确凿的证据,表明上地幔和地幔转换带中的横向非均匀性的强度要远胜于下地幔。我们精确测量的Pdiff波的走时数据表明,在地幔底部存在显著的低速异常,可能与地幔热柱或者超级地幔柱有关。我们使用了一个最新的三维全球层析成像模型来解释这些体波走时数据的空间变化。 展开更多
关键词 地幔体波 地震层析成像 地幔非均匀性 地幔热柱 俯冲板片
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Randomized clinical trial of an ethanol extract of Ganoderma lucidum in men with lower urinary tract symptoms 被引量:2
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作者 Masanori Noguchi Tatsuyuki Kakuma +7 位作者 Katsuro Tomiyasu akira yamada Kyogo Itoh Fumiko Konishi Shoichiro Kumamoto Kuniyoshi Shimizu Ryuichiro Kondo Kei Matsuoka 《Asian Journal of Andrology》 SCIE CAS CSCD 2008年第5期777-785,共9页
Aim: To evaluate the safety and efficacy of an extract of Ganoderma lucidum that shows the strongest 5α-reductase inhibitory activity among the extracts of 19 edible and medicinal mushrooms by a double-blind, placeb... Aim: To evaluate the safety and efficacy of an extract of Ganoderma lucidum that shows the strongest 5α-reductase inhibitory activity among the extracts of 19 edible and medicinal mushrooms by a double-blind, placebo-controlled, randomized and dose-ranging study in men with lower urinary tract symptoms (LUTS). Methods: In this trial, we randomly assigned 88 men over the age of 49 years who had slight-to-moderate LUTS to 12 weeks of treatment with G. lucidum extract (6 mg once a day) or placebo. The primary outcome measures were changes in the International Prostate Symptom Score (IPSS) and variables of uroflowmetry. Secondary outcome measures included changes in prostate size, residual urinary volume after voiding, laboratory values and the reported adverse effects. Results: G. lucidum was effective and significantly superior to placebo for improving total IPSS with 2.1 points decreasing at the end of treatment (mean difference, -1.18 points; 95% confidence interval, -1.74 to -0.62; P 〈 0.0001). No changes were observed with respect to quality of life scores, peak urinary flow, mean urinary flow, residual urine, prostate volume, serum prostate-specific antigen or testosterone levels. Overall treatment was well tolerated with no severe adverse effects. Conclusion: The extract of G. lucidum was well tolerated and improved IPSS scores. These results encouraged a further, large-scale evaluation of phytotherapy for a long duration using the extract of G. lucidum on men with LUTS. 展开更多
关键词 lower urinary tract symptoms PHYTOTHERAPY OUTCOME randomized trial Ganoderma lucidum
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Managing High Volume Data for Network Attack Detection Using Real-Time Flow Filtering
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作者 Abhrajit Ghosh Yitzchak M. Gottlieb +5 位作者 Aditya Naidu Akshay Vashist Alexander Poylisher Ayumu Kubota Yukiko Sawaya akira yamada 《China Communications》 SCIE CSCD 2013年第3期56-66,共11页
In this paper, we present Real-Time Flow Filter (RTFF) -a system that adopts a middle ground between coarse-grained volume anomaly detection and deep packet inspection. RTFF was designed with the goal of scaling to hi... In this paper, we present Real-Time Flow Filter (RTFF) -a system that adopts a middle ground between coarse-grained volume anomaly detection and deep packet inspection. RTFF was designed with the goal of scaling to high volume data feeds that are common in large Tier-1 ISP networks and providing rich, timely information on observed attacks. It is a software solution that is designed to run on off-the-shelf hardware platforms and incorporates a scalable data processing architecture along with lightweight analysis algorithms that make it suitable for deployment in large networks. RTFF also makes use of state of the art machine learning algorithms to construct attack models that can be used to detect as well as predict attacks. 展开更多
关键词 network security intrusion detection SCALING
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Frequency Control of Power System with Solar and Wind Power Stations by Using Frequency Band Control and Deadband Control of HVDC Interconnection Line
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作者 Kimiko Tada Takamasa Sato +5 位作者 Atsushi Umemura Rion Takahashi Junji Tamura Yoshiharu Matsumura Tsukasa Taguchi akira yamada 《Journal of Power and Energy Engineering》 2018年第9期48-63,共16页
In recent years, environmental problems are becoming serious and renewable energy has attracted attention as their solutions. However, the electricity generation using the renewable energy has a demerit that the outpu... In recent years, environmental problems are becoming serious and renewable energy has attracted attention as their solutions. However, the electricity generation using the renewable energy has a demerit that the output becomes unstable because of intermittent characteristics, such as variations of wind speed or solar radiation intensity. Frequency fluctuations due to the installation of large scale wind farm (WF) and photovoltaics (PV) into the power system is a major concern. In order to solve the problem, this paper proposes two control methods using High Voltage Direct Current (HVDC) interconnection line to suppress the frequency fluctuations due to large scale of WF and PV. Comparative analysis between these two control methods is presented in this paper. One proposed method is a frequency control using a notch filter, and the other is using a deadband. Validity of the proposed methods is verified through simulation analyses, which is performed on a multi-machine power system model. 展开更多
关键词 High Voltage Direct Current (HVDC) System Frequency CONTROL PV POWER GENERATION Wind POWER GENERATION Notch Filter Deadband
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Passive Seismic Deployments from the Lützow-Holm Bay to Inland Plateau of East Antarctica: The Japanese IPY Contribution to Structure and Seismicity
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作者 Masaki Kanao akira yamada Genti Toyokuni 《International Journal of Geosciences》 2013年第5期837-843,共7页
Deployments of seismic stations in Antarctica are an ambitious project to improve the spatial resolution of the Antarctic Plate and surrounding regions. Several international programs had been conducted in wide area o... Deployments of seismic stations in Antarctica are an ambitious project to improve the spatial resolution of the Antarctic Plate and surrounding regions. Several international programs had been conducted in wide area of the Antarctic continent during the International Polar Year (IPY 2007-2008). The “Antarctica’s GAmburtsev Province (AGAP)”, the “GAmburtsev Mountain SEISmic experiment (GAMSEIS)” as a part of AGAP, and the “Polar Earth Observing Network (POLENET)” were major contributions to the IPY. The AGAP/GAMSEIS was an internationally coordinated deployments of more than few tens of broadband seismographs over the wide area of East Antarctica. Detailed information on crustal thickness and mantle structure provides key constraints on an origin of the Gamburtsev Mountains;and more broad structure and evolution of the East Antarctic craton and sub-glacial environment. From POLENET data obtained, local and regional signals associated with ice movements were recorded together with a significant number of teleseismic events. Moreover, seismic deployments have been carried out in the Lützow-Holm Bay (LHB), East Antarctica, by Japanese activities. The recorded teleseismic and local events are of sufficient quality to image the structure and dynamics of the crust and mantle, such as the studies by receiver functions suggesting a heterogeneous upper mantle. In addition to studies on the shallow part of the Earth, we place emphasis on these seismic deployments’ ability to image the Earth’s deep interior, as viewed from Antarctica, as a large aperture array in the southern high latitude. 展开更多
关键词 PASSIVE SEISMIC Deployments Lützow-Holm BAY East Antarctica Mantle STRUCTURE Earth’s Deep INTERIORS
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器官异种移植的历史、现状和未来 被引量:2
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作者 akira yamada Hugh Auchincloss Jr +1 位作者 黄昕 毛一雷 《中国实用外科杂志》 CSCD 北大核心 2001年第5期314-316,共3页
关键词 器官移植 异种移植 排斥反应 预防
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