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激电法在辽宁柏杖子金矿勘查中的作用及意义  [PDF]
李祥才
地质与勘探 , 2009,
Abstract: 辽宁柏杖子金矿床是冀东金矿带大型金矿之一,金矿化类型为含金黄铁矿石英细脉浸染型和含金黄铁矿石英脉型,大部分金矿矿体是隐伏矿体,矿体与围岩电性差异明显,矿床普查阶段开展了电阻率中梯测量、激电中梯测量和激电测深工作。矿体具有低阻高极化特点,异常带与矿区主构造和花岗斑岩吻合一致,因此由以往围绕北西向小矿体找矿,改变为沿矿区主构造和花岗斑岩寻找隐伏矿体,根据电法异常布设钻孔,取得了显著找矿效果。
基于改进Krylov子空间算法的井中激电反演  [PDF]
李长伟,熊彬,王有学,罗润林
地球物理学报 , 2012, DOI: 10.6038/j.issn.0001-5733.2012.11.034
Abstract: 井中激电是二次找矿重要的地球物理勘探手段,快速而稳定的正反演算法有助于方法的推广和应用.本文在正演模拟中,给出了考虑井眼影响下的网格剖分方式;用右端项校正技术减小边界效应和源点奇异性引起的模拟误差;并采用循环Krylov子空间算法提高多线性方程组的求解效率.反演用Gauss-Newton法结合Jacobian-freeKrylov迭代求解技术,给出了Jacobian矩阵向量积的简化计算方法;用不精确预处理共轭梯度法对模型修正量方程近似求解以减少计算量;采用不同于正演的反演网格剖分降低不适定性.数值算例验证了相关算法的有效性和可靠性.
Cooling force on ions in a magnetized electron plasma  [PDF]
H. B. Nersisyan,G. Zwicknagel
Physics , 2011,
Abstract: Electron cooling is a well-established method to improve the phase space quality of ion beams in storage rings. In the common rest frame of the ion and the electron beam the ion is subjected to a drag force and it experiences a loss or a gain of energy which eventually reduces the energy spread of the ion beam. A calculation of this process is complicated as the electron velocity distribution is anisotropic and the cooling process takes place in a magnetic field which guides the electrons. In this paper the cooling force is calculated in a model of binary collisions (BC) between ions and magnetized electrons, in which the Coulomb interaction is treated up to second-order as a perturbation to the helical motion of the electrons. The calculations are done with the help of an improved BC theory which is uniformly valid for any strength of the magnetic field and where the second-order two-body forces are treated in the interaction in Fourier space without specifying the interaction potential. The cooling force is explicitly calculated for a regularized and screened potential which is both of finite range and less singular than the Coulomb interaction at the origin. Closed expressions are derived for monochromatic electron beams, which are folded with the velocity distributions of the electrons and ions. The resulting cooling force is evaluated for anisotropic Maxwell velocity distributions of the electrons and ions.
Electron conduction in magnetized neutron star envelopes  [PDF]
A. Y. Potekhin
Physics , 1999,
Abstract: Practical expressions are derived for evaluation of electrical and thermal conductivities and thermopower of degenerate electrons in the outer envelopes of neutron stars with magnetic fields. All tensor components of the kinetic coefficients are calculated (those related to conduction along and across magnetic field and to the Hall currents). The kinetic coefficients are presented as energy averages of expressions containing energy dependent effective relaxation times of two types, associated either with longitudinal or with transverse currents. The calculation is based on the effective scattering potential proposed in the previous paper (astro-ph/9903127), which describes the electron-ion and electron-phonon scattering, taking into account correlation effects in strongly coupled Coulomb liquid and multi-phonon scattering in Coulomb crystal, respectively. Analytic fitting formulae are devised for the effective relaxation times at arbitrary field strength. Basing on these results, we calculate the transport coefficients at various temperatures, densities, and magnetic fields pertinent to the neutron star envelopes.
The Magnetized Electron Gas in terms of Hurwitz Zeta Functions  [PDF]
Claudio O. Dib,Olivier R. Espinosa
Physics , 2000, DOI: 10.1016/S0550-3213(01)00360-1
Abstract: We obtain explicit expressions for thermodynamic quantities of a relativistic degenerate free electron gas in a magnetic field in terms of Hurwitz Zeta functions. The formulation allows for systematic expansion in all regimes. Three energy scales appear naturally in the degenerate relativistic gas: the Fermi energy Ef, the temperature T and an energy related to the magnetic field or Landau level spacing, eB/Ef. We study the cold and warm scenarios, T << eB/Ef and eB/Ef << T, respectively. We reproduce the oscillations of the magnetization as a function of the field in the cold regime and the dilution of them in the warm regime.
Relativistic Thermodynamics of Magnetized Fermi Electron Gas  [PDF]
Nodar L. Tsintsadze,Levan N. Tsintsadze
Physics , 2012,
Abstract: To study the relativistic thermodynamic properties of a Fermi gas in a strong magnetic field, we construct the relativistic thermodynamic potential by the relativistic Fermi distribution function taking into account that the motion of particles in a plane perpendicular to the magnetic field is quantized. With this general potential at hand, we investigate all the thermodynamic quantities as a function of densities, temperatures and the magnetic field. We obtain a novel set of adiabatic equations. Having the expression of the pressure and adiabatic state equations, we determine the sound velocity for several cases revealing a new type of sound velocity. Finally, we disclose the magnetic cooling in the quantized electron Fermi gas, which is based on an adiabatic magnetization in contrast to the known adiabatic demagnetization.
Electron velocity distribution instability in magnetized plasma wakes and artificial electron mass  [PDF]
I. H. Hutchinson
Physics , 2011, DOI: 10.1029/2011JA017119
Abstract: The wake behind a large object (such as the moon) moving rapidly through a plasma (such as the solar wind) contains a region of depleted density, into which the plasma expands along the magnetic field, transverse to the flow. It is shown here that (in addition to any ion instability) a bump-on-tail which is unstable appears on the electrons' parallel velocity distribution function because of the convective non-conservation of parallel energy. It arises regardless of any non-thermal features on the external electron velocity distribution. The detailed electron distribution function throughout the wake is calculated by integration along orbits; and the substantial energy level of resulting electron plasma (Langmuir) turbulence is evaluated quasilinearly. It peaks near the wake axis. If the mass of the electrons is artificially enhanced, for example in order to make numerical simulation feasible, then much more unstable electron distributions arise; but these are caused by the unphysical mass ratio.
经典电振子辐射阻尼常数的统计确定  [PDF]
朱如曾
物理 , 1979,
Abstract: ?一、引言如所熟知,经典电子谐振子在经典的微观电动力学中占有极为重要的地位.下面的讨论针对电子振子,但所有的论述稍加修改几乎完全适合于一般的经典电振子.经典电子谐振子的辐射阻尼常数的传统推导有如下述[1,2].就一维自由谐振子而言,出发点是运动方程其中,m和e分别为电子的质量和电量,c为光速.v20是振子的固有频率.左边第三项是电子的辐射阻尼力.方程的适用条件要求阻尼力远小于其他的力[3].故?...
双极电凝在腹腔镜下全子宫切除术中的应用  [PDF]
李卫红,张素丽,张振立,于峰
华西医学 , 2010,
Abstract: 【】目的探讨双极电凝在腹腔镜下全子宫切除术中的应用价值。方法回顾分析2006年1月-2009年12月收治240例腹腔镜下全子宫切除术患者的治疗资料,其中双电凝组、超声刀组各120例,比较两种方法在腹腔镜下全子宫切除术的手术时间、出血量、并发症、住院时间。结果手术时间双极电凝组平均98.23min,超声刀组平均95.42min,术中出血量双极电凝组平均90.52mL,超声刀组平均96.04mL,术后住院天数、并发症均无差异。结论双极电凝在腹腔镜下全子宫切除术中应用是安全可行的,尤其在基层医院值得推广。
Electron transport through nuclear pasta in magnetized neutron stars  [PDF]
D. G. Yakovlev
Physics , 2015, DOI: 10.1093/mnras/stv1642
Abstract: We present a simple model for electron transport in a possible layer of exotic nuclear clusters (in the so called nuclear pasta layer) between the crust and liquid core of a strongly magnetized neutron star. The electron transport there can be strongly anisotropic and gyrotropic. The anisotropy is produced by different electron effective collision frequencies along and across local symmetry axis in domains of exotic ordered nuclear clusters and by complicated effects of the magnetic field. We also calculate averaged kinetic coefficients in case local domains are freely oriented. Possible applications of the obtained results and open problems are outlined.
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