大位移井中利用钻柱旋转作用清除岩屑床的机理研究

井眼净化 ,是大位移钻井的关键技术之一 ;大位移井中 ,岩屑床是制约井眼净化的关键性因素。除钻井水力、钻井液流变参数外 ,钻柱的旋转作用是清除岩屑床的一个重要因素。通过对钻柱旋转作用下的环空流场的研究和分析 ,揭示了钻柱旋转对清除岩屑床的力学机理 ,即旋转作用使压力分布呈现波动形式 ,产生了有利于清除岩屑的循环力和陀螺力。波动的压力使岩屑床趋于非稳定 ,而循环力和陀螺力则对岩屑床产生搅动和支承作用 ,便于环空上返流速对岩屑的携带。并以国内大港油田大位移井红 9— 1为例 ,说明了钻柱旋转在大位移井中对清除岩屑床的重要作用。

旋转作用强化膜过滤装置评述

评述了当前利用旋转作用强化膜过滤的三种典型装置 ,即旋转盘式膜器、旋转膜管式膜器和旋转流管式膜器 ,包括它们各自的结构、机理。

反旋转波相互作用对非平衡自旋玻色模型热输运性质的影响

随着实验技术的发展,量子系统中已经实现了强和超强自旋-腔、自旋-环境相互作用。很大一类光学腔和耗散环境可以用波色热库描述。在强系统-热库耦合条件下,之前适用于弱耦合条件下的旋波近似失效,需要考虑系统-热库的反旋转波相互作用对系统动力学演化和稳态行为的影响。使用正则变换和全计数统计方法,研究系统-热库反旋转波相互作用对热输运性质的影响。结果表明:在弱耦合情况下采用旋波近似时,稳态热流、噪声功率以及热力学不确定关系随温度单调增大。强耦合情况,反旋转波相互作用下,以上物理量呈非单调性:先增大后减小。在弱耦合情况下采用旋波近似时,热力学不确定关系与耦合强度无关。强耦合情况,反旋转波相互作用下,热力学不确定关系随着耦合强度的增大而减小,向热力学不确定关系的下限逼近。说明量子相干性有助于提高量子热机的性能,使其优于经典热机。

截面形状对旋转扰流柱通道流动换热特性的影响

为合理设计航空发动机涡轮动叶尾缘冷却结构,采用ANSYS FLUENT软件模拟了四种扰流柱截面形状在旋转状态下的流动换热特性。对比分析了不同旋转数(Ro)和不同扰流柱截面形状时通道内部的三维流场分布、湍流动能分布、努塞尔数(Nu)分布以及阻力系数。其中扰流柱的截面形状包含圆形、菱形、矩形和椭圆形,Ro数包含0、0.2、0.4和0.6四种数值。模拟过程中通道入口雷诺数为7000,壁面恒定热流为1000 W/m^(2)。结果表明,截面形状和旋转数对流动和换热状态有着显著影响,矩形扰流柱通道的换热系数和阻力系数最高;随着旋转数的增加,迎风面和背风面的换热系数差异逐渐增大;在旋转作用下,扰流柱尾缘区域出现了纵向二次流,该二次流显著破坏了壁面附近的边界层,有利于背风面换热增强。

种植体—基桩(台)界面结构的研究

两段式种植体系的种植体—基桩界面,是近年来口腔种植及修复学中出现的新概念、新名词。临床实践结果表明,该界面的精密连接与稳定性,是确保种植体在植入后能否长期而有效地行使功能的关键因素之一。本文就该界面的结构组成、结构原理、影响该界面稳定的因素,以及有关的研究方法等进行综述。

塑料弹带提高射击密集度的研究

本文介绍的滑动式塑料弹带能够明显地提高线膛炮发射的尾翼弹的射击密集度。文中探讨了塑料弹带的闭气、定心和旋转作用以及从理论上探讨了减小尾翼弹起始扰动和外形不对称对散布的影响原因,并用实验做了验证。

离心薄膜真空蒸发器

本文介绍了离心薄膜真空蒸发器的结构,用途和一系列优点。

射钉枪致人死亡1例

袁××,女,21岁,1992年元月18日晚8时许在家看电视时被枪击致死,并盗走人民币4万余元。尸检见:射入口位于枕外粗隆左侧2cm处。头发有烧灼痕迹,头皮组织有直径为0.7cm圆形创口,创缘整齐、内翻,挫伤不明显,创周有1.2cm×1.

汶川地震断裂带科学钻探1号井(WFSD-1)非弹性应变恢复法(ASR法)三维地应力测试与“5.12”汶川地震的形成机制

汶川地震断裂带科学钻探1号井(WFSD-1)的ASR三维地应力测试结果表明,龙门山前陆逆冲带与其下伏的龙门山前陆盆地和上覆的松潘-甘孜地块的构造及地应力状态存在有重大差异。从整体上看,在汶川地震中,龙门山前陆逆冲带表现为在强烈的区域性挤压背景下,深部物质沿壳内拆离层自SW向NE方向的"层状"流动,在地壳上部转化为沿映秀-北川断裂(YBF)的快速垂向挤出,而其西侧的松潘-甘孜地块作自SE往NW方向的重力滑覆,东侧的龙门山前陆盆地则表现为自NE往SW方向的走滑或右行旋转。晚新生代以来,扬子地块相对于青藏高原东缘的龙门山造山带并无明显的或大尺度的陆内俯冲作用发生。龙门山前陆逆冲带深部高温低粘度物质垂直向上的、快速的流动和挤出,直接导致了"5.12"汶川地震的发生,而松潘-甘孜地块E向扩展导致龙门山前陆带的强烈挤压和陆壳增厚及深部应力和地震能量的积聚则是诱导深部位移场发生突变和物质快速垂向挤出的主因,E向扩展是深部地震能量积聚和快速垂向挤出作用的必要条件,而非地震发生的直接原因。ASR地应力测试得出的主压应力方向完全平行于GPS同震速度场的位移方向,似乎表明ASR测试获得的原地应力场或许真实地反映了或最接近于地震过程中的构造应力状态。

Characterization of coal using electron spin resonance： implications for the formation of inertinite macerals in the Witbank Coalfield, South Africa

Coal contains a significant concentration of free radicals as a result of the coalification process. One of the experimental methods sensitive to the presence of radicals is electron spin resonance （ESR）, and differences in ESR spectra for different macerals may provide insight into coal-forming processes. In this study, ESR data along with the H/C atomic ratio （to infer the aromatic fraction） are used to characterize coal samples with the aim of assessing a fire-origin for dominant inertinite macerals. A medium rank C bituminous Witbank No. 4 Seam Upper coal （the parent） was density- fractionated to create vitrinite-rich and inertinite-rich samples. The parent sample consists of 42 vol% vitrinite and 49 vol% inertinite. The density-fractionated samples comprise of 81 vol% total vitrinite （dominated by collotelinite and collodetrinite）, and 63 vol% total inertinite （dominated by fusinite, semifusinite, and inertodetrinite）. The H/C ratio is 0.74 for the inertinite-rich sample, and 0.85 for the vitrinite-rich counterpart, suggesting the former sample is more aromatic. The ESR spectra obtained for the three samples were found to fit best using a Lorentzian distribution. The fit is noticeably better for the aromatic inertinite-rich sample, for which the spectrum is symmetric. This is attributed to pronounced electron mobility and exchange interactions. The higher radical content of the inertinite-rich and parent samples is attributed to the presence of specific inertinite macerals, namely： fusinite, semifusinite, and inertodetrinite. And, owing to the greater radical content of the inertinite-rich sample, the dominant inertinite macerals are interpreted to have formed through charring of plant matter.

Dynamic simulation of a flexible spinning vehicle with the periodic varying thrust

The dynamic response of a flexible spinning vehicle with the varying thrust was investigated. The varying thrust was modeled as a series of simple harmonic components superimposed on a constant thrust. The analytical solutions for longitudinal motion were obtained by combining the motion equations and boundary conditions, and then, the transverse bending of rocket was examined solved by considering a coupled forcing vibration with varying parameters. Numerical solutions for a rocket with end-varying thrust were studied. It is shown that the lateral vibrations and motion attitudes of rocket depend on the frequencies of varying thrust to great extent, and an important phenomenon, beating, maybe take place. The proposed approach is more accurate and efficient in comparison to those standard numerical techniques.

Ab initio Study of Electronic Structure and Magnetic Properties of Two Novel Neptunium （V） Sulfates： iaK3（ipO2）4（SO4）4（H2O）2 and iaipO2SO4H2O

Ab initio within the full potential linearized augmented plane wave （FP-LAPW） method with the GGA＋U approach is applied to study the electronic structures of two compounds NaK3（NpO2）4（SO4）4（H2O）2 and NaNpO2SO4H2O. The present calculations show that the major part of the spin magnetic moment in these two compounds is from Np（V） ions, and the origin of the cation-cation interactions between Np comes from the spin polarization effect within Np-ONv-Np bonds.

Pressure Effects on Spectra of Tunable Laser Crystal GSGG:Cr3+ III: Pressure-Induced Shift of R1 Line at 70 K

By means of both a theory for pressure-induced shifts (PS) of energy spectra and a theory for shifts of energy spectra due to electron-phonon interaction (EPI), the 'pure electronic' PS and the PS due to EPI of R1 line of GSGG:Cr3+ at 70 K have been calculated, respectively. Their physical origins have been revealed. It is found that the admixture of and base-wavefunctions in the wavefunctions of R1 level of GSGG:Cr3+ at 70 K is remarkable under the normal pressure, and the degree of the admixture rapidly decreases with increasing pressure. The change of the degree of the admixture with the pressure plays a key role for not only the pure electronic PS of R1 line but also the PS of R1 line due to EPI. The detailed calculations and analyses show that the pressure-dependent behaviors of the pure electronic PS of R1 line and the PS of R1 line due to EPI are quite different. It is the combined effect of them that gives rise to the total PS of R1 line, which has satisfactorily explained the experimental data (including a reversal of PS of R1 line). In contributions to PS of R1 line due to EPI at 70 K, the temperature-independent contribution is much larger than the temperature-dependent contribution. The former results from the interaction between the zero-point vibration of the lattice and localized electronic state.

Synergistic and interference effects in coaxial mixers: Numerical analysis of the power consumption

This paper is concerned with the design and application of coaxial mixers with the aid of analysis of interaction between each individual impeller. Two types of coaxial mixers pitched blade turbine(PBT)-helical ribbon(HR)and inner-outer HR operated in laminar regime were studied experimentally and numerically. The interaction implies synergistic and interference effects, which was revealed through the investigation of axial circulation rate, energy dissipation rate and power consumption. The influence factors including rotational speed ratio,rotating mode and impeller configuration were explored systematically. Quantitative analysis of power consumption involves three parameters: rate of variation in power consumption, interactive mode and ratio of power consumption. Analysis indicated that some important properties were embodied in the power curve.These properties are one-way and two-way interactions, critical speed ratio and dominant impeller. Finally, a new suggestion for power estimation was given.

Quantum Phase Transitions and Dimerized Phases in Frustrated Spin Ladder

In this paper, we study the phase diagram of a frustrated spin ladder model by applying the bosonization technique and the density-matrix renormalization-group （DMRG） algorithm. Effect of the intra-ehain next-nearest- neighbor （NNN） super-exchange interaction is investigated in detail and the order parameters are calculated to detect the emergence of the dimerized phases. We find that the intra-chain NNN interaction plays a key role in inducing dimerized phases.

Comparative analysis of residence and diffusion times in rotating bed used for biogas upgrading

Rotating bed can be used in desorption operation of biogas upgrading as a new technology. For enough time to desorb, it is important to study the relationship between the residence time of liquid in rotating bed and the material diffusion time of liquid droplet in desorption process. By theoretical deduction, the exponential relation between residence time and liquid flow rate and rotational speed and kinematic viscosity is obtained. By analyzing the solution of nonlinear partial differential equation, the time law of material diffusion in the droplet is obtained. Moreover, by comparing the residence and diffusion times, the diffusion time can be within or out of residence time range, which has a direct relationship to rotational speed and liquid flow. By experiment, the comparison between residence and diffusion times is more realistic when the rotational speed is higher.

Study on Industrial Application of Hydrogen Sulfide Removal by Wet Oxidation Method with High Gravity Technology

The removal of hydrogen sulfide from gas plays an important role in rational utilization of resources and environ- mental protection. In this paper, the process of hydrogen sulfide removal by wet oxidation method in a rotating packed bed was investigated in a scale for treating 10 000 Nm3/h of gas. On the basis of studying the influence of the species and con- centration of alkali source, the liquid/gas volume ratio, the high gravity factor, and the hydrogen sulfide content in feed gas on the desulfurization effect, the suitable technological conditions were obtained. The hydrogen sulfide removal efficiency could reach 98.0% under these conditions. The results of continuous operation of process facilities showed that the high gravity method has many merits including higher desulfurization rate, good stability in operation, lower liquid/gas volume ratio, greater operation elasticity, and apparent energy saving effects.

A Rotating Bose-Einstein Condensation in a Toroidal Trap

We have studied the ground state configurations of a rotating Bose-Einstein condensation in a toroidal trap as the radius of the central Ganssian potentiaJ expands adiabatically. Firstly, we observe that the vortices are devoured successively into the central hole of the condensate to form a giant vortex as the radius of the trap expands. When all the pre-existing vortices are absorbed, the angular momentum of the system still increase as the radius of the ganssian potential enlarges. When increasing the interaction strength, we find that more singly quantized vortices are squeezed into the condensate, but the giant vortex does not change.

Description of Chiral Doublet Bands in Odd-Odd Cs Isotopes

Properties of the chair doublet bands of the odd-odd Cs isotopes built on the πh11/2× vh11/2 configuration are investigated systematically within the supersymmetry scheme including many-body interactions and possessing the SO（5）（or SU（5）） symmetry on the rotational symmetry. Quantitatively good results of the energy spectra, the energy staggering parameter as a function of the spin are obtained. The calculation shows that the stronger competition between the pairing and anti-pairing effects and the SU（3） symmetry broking more seriously exist in the stable chiral structure.

Effect of wind fluctuating on self-starting aerodynamics characteristics of VAWT

The present work deals with an investigation of the self-starting aerodynamic characteristics of VAWT under fluctuating wind. In contrast to the previous studies, the rotational speed of the turbine is not fixed, the rotation of the turbine is determined by the dynamic interaction between the fluctuating wind and turbine. A weak coupling method is developed to simulate the dynamic interaction between the fluctuating wind and passive rotation turbine, and the results show that if the fluctuating wind with appropriate fluctuation amplitude and frequency, the self-starting aerodynamic characteristics of VAWT will be enhanced. It is also found that compared with the fluctuation amplitude, the fluctuation frequency of the variation in wind velocity is shown to have a minor effect on the performance of the turbine. The analysis will provide straightforward physical insight into the self-starting aerodynamic characteristics of VAWT under fluctuating wind.