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41.
42.
塔里木盆地富满油田二叠系普遍发育有玄武岩,玄武岩段钻进易发生井壁失稳,引起卡钻等井下故障复杂,影响了在该区块钻井时效和经济效益。通过对二叠系玄武岩进一步结构特征研究、易垮井地震相态特征及实钻特征研究、理化特性、地应力、坍塌压力研究,确定引起井壁失稳的原因。根据该区块现场实钻资料及井壁失稳处理经验,从强化钻井液封堵性、控制滤失量、提高钻井液抑制性、携岩能力、密度优选、控制工程参数等几个方面给出避免二叠系玄武岩井壁失稳的处理建议。研究成果在AM3井应用成功,效果显著,对指导富满油田二叠系玄武岩钻进具有一定的指导意义。 相似文献
43.
带状注是指束流截面近似为矩形或椭圆形的电子注,且具有大的宽高比。相对于传统的圆形注,带状注具有很多优点,例如大电流和大互作用面积等。由于太赫兹波具有高频率、宽频带、高传输速率等优点,因此太赫兹科学与技术近年来发展迅速。作为一种新型的真空电子器件,太赫兹带状注器件在高功率、高增益、高效率及小型化方面具有良好的技术优势。但是,带状注在传输过程中易出现Diocotron不稳定性,难以保持长距离稳定的聚焦传输,从而导致带状注的技术优势难以发挥。本文综述了带状注的产生成形方式和聚焦传输方法,以及太赫兹带状注器件的研究进展,同时讨论了它所面临的挑战和未来的发展方向。 相似文献
44.
利用相对论电磁粒子模拟程序研究了超强激光与等离子体相互作用过程中产生的自生磁场和电子热输运特性。讨论了自生磁场产生机制和非线性饱和过程。给出了自生磁场的线性增长率和各向异性参数之间的函数关系,用Spitzer-Harm理论分析了电子热传导中能量的运输情况,观察到由激光的非等方加热引起的电子纵向加热现象。细致研究这些过程对更好的理解快点火物理中自生磁场的产生、超热电子热输运等过程有重要意义。 相似文献
45.
Naoto Suzuki 《Electrical Engineering in Japan》2010,171(2):23-30
In Kyushu Electric Power's 6.6‐kV distribution system, after a single‐phase ground fault occurred in the circuit of a distribution line, we experienced a phenomenon in which the analogue ground directional relays of the other circuits linked to the same bank were simultaneously tripped. In this paper, focus is placed on the mechanism and possibility of simultaneous tripping of ground directional relays. This mechanism was examined in an experiment carried out using an analogue simulator. The results of the test revealed that such simultaneous tripping was attributable to the neutral instability phenomenon of grounding potential transformers installed in an isolated neutral system. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 171(2): 23–30, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20919 相似文献
46.
Considering that there are some limitations in analyzing the anti-sliding seismic stability of dam-foundation systems with the traditional pseudo-static method and response spectrum method,the dynamic strength reduction method was used to study the deep anti-sliding stability of a high gravity dam with a complex dam foundation in response to strong earthquake-induced ground action.Based on static anti-sliding stability analysis of the dam foundation undertaken by decreasing the shear strength parameters of ... 相似文献
47.
Dhananjay Yadav G.S. Agrawal R. Bhargava 《International Journal of Engineering Science》2011,49(11):1171-1184
In the present paper we have considered thermal instability of rotating nanofluids heated from below. Linear stability analysis has been made to investigate analytically the effect of rotation. The more important effect of Brownian motion and thermophoresis has been included in the model of nanofluid. Galerkin method is used to obtain the analytical expression for both non-oscillatory and oscillatory cases, when boundaries surfaces are free–free. The influence of various nanofluids parameters and rotation on the onset of convection has been analysed. It has been shown that the rotation has a stabilizing effect depending upon the values of various nanofluid parameters. The critical Rayleigh number for the onset of instability is determined numerically and results are depicted graphically. The necessary and sufficient conditions for the existence of over stability are also obtained. 相似文献
48.
M.C. Maccarone O. CatalanoS. Giarrusso G. La RosaA. Segreto G. AgnettaB. Biondo A. ManganoF. Russo S. Billotta 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2011,659(1):569-578
UVscope is a portable multi-pixels photon detector developed at IASF-Pa to support experimental activities in the high-energy astrophysics and cosmic rays field. The instrument, working in single photon counting mode, is designed to directly measure light flux in the wavelengths range 300-650 nm. Thanks to its features and operational flexibility, the instrument can be used in a wide field of applications where the knowledge of the environmental luminosity is required, as in the characterization of sites for ground-based Cherenkov and fluorescence telescopes, and for cross-calibration of their cameras.The present version of UVscope is based on a Multi Anode Photo Multiplier Tube and it is completed by a motorized mount and a filter wheel which allow to make low-light measurements, at programmed pointing directions and at different filter wavelengths. In this paper, the instrument is firstly presented in all its components; then the procedures adopted for its absolute and relative calibration are detailed. The performance of UVscope is evaluated and, finally, current and planned scientific applications are described. 相似文献
49.
介绍了边坡工程地质条件,分析了边坡变形的特征及成因,阐述了边坡稳定性的计算方法,并对其计算结果作了分析,对边坡的变形、检测等得出一些结论。 相似文献
50.
MA Ling-Ling BAI Yun-Xiang CAO Zhen CHEN Ming-Jun CHEN Li-Hong CHEN Song-Zhan CHEN Yao DING Kai-Qi HE Hui-Hai LIU Jia LIU Jia-Li LI Xiao-Xiao MA Xin-Hua SHENG Xiang-Dong XIAO Gang ZHA Min ZHANG Shou-Shan ZHANG Yong ZHAO Jing ZHOU Bin 《Canadian Metallurgical Quarterly》2011,35(5)
The Large High Altitude Air Shower Observatory (LHAASO) project is proposed to study high energy gamma ray astronomy (40 GeV–1 PeV) and cosmic ray physics (20 TeV–1 EeV). The wide field of view Cherenkov telescope array, as a component of the LHAASO proje 相似文献