12.7mm钨心脱壳穿甲弹横弹分析与研究

12.7毫米钨心脱壳穿甲弹近距离出现横弹孔,从脱壳弹自身特点、脱壳弹制造工艺及质量、所用枪的状态以及现行判定方法的不合理性等方面进行分析与研究,指出在诱发12.7毫米钨心脱壳穿甲弹横弹的诸因素中,闭气环的影响居首位。对闭气环的生产控制、现有横弹判定方法的修订、改进底托设计等提出具体措施与建议。

弹拨颈外横突治疗点治疗颈源性肩周炎63例疗效观察

目的:观察弹拨颈外横突治疗点治疗颈源性肩周炎的临床疗效。方法:采用随机数字表法将颈源性肩周炎患者126例随机分为观察组和对照组各63例,观察组取颈外横突治疗点进行弹拨,对照组应用扌衮法、揉法、拿捏等推拿手法施治于肩部,观察两组患者治疗前后疼痛强度评分、肩关节功能评分及综合评分的变化情况并进行组间比较。结果:观察组治愈率为46.03%、总有效率为95.24%,对照组治愈率为19.05%、总有效率为87.30%,两组比较差异均有统计学意义(P均<0.05)。结论:弹拨颈外横突治疗点治疗颈源性肩周炎效果显著。

弹拨颈外横突治疗点与针刺法治疗颈源性肩周炎临床疗效观察

目的通过对比研究方法,观察弹拨颈外横突治疗点、针刺两种方法治疗颈源性肩周炎的临床疗效,为颈源性肩周炎的治疗提供简便效捷的适用技术。方法采用随机数字表法将颈源性肩周炎患者126例随机分为观察组和对照组,每组各63例。观察组取颈外横突治疗点进行弹拨;对照组取大椎、阿是穴(压痛点)、夹脊穴(双),患侧新设、大杼、悬钟、中渚、养老、合谷等穴行常规针刺。1次/d,10次/疗程,两个疗程后行疗效对比分析。观察两组患者治疗前后疼痛强度评分、肩关节功能评分及综合评分的变化情况以及两组间疗效比较。结果两种方法均能有效改善患者症状和体征。观察组治疗前后疼痛强度评分比较(P<0.01),肩关节功能评分比较(P<0.05),差异均有统计学意义。对照组治疗前后疼痛强度评分比较(P<0.05);肩关节功能评分比较(P<0.05),差异均有统计学意义。治疗组与对照组治疗后疼痛强度评分比较(P<0.05),差异有统计学意义。观察组总有效率为96.83%,对照组总有效率为90.48%,两组总有效率比较(P>0.05),差异无统计学意义;但两组治愈率(分别为46.03%和20.63%)比较,差异有统计学意义(P<0.05)。结论弹拨颈外横突治疗点与针刺法均能有效缓解疼痛并改善肩关节活动功能。但弹拨颈外横突治疗点在提高临床治愈率和减轻疼痛方面明显优于针刺法。

瑞士双35mm牵引高炮内弹道指标设计特点分析

为杜绝压力波的出现,控制初始燃烧速率,瑞士厄里空公司双35mm高炮的内弹道指标设计最早引入了点火延迟时间(t2)作为发射药、底火生产厂的必测指标,同时底火厂也将t1作为必测指标,发射药厂还将监测t1、t4、炮口焰和炮口压力。厄里空公司将35mm高炮的内弹道指标设计作为系统工程设计,这是设计先进性的保证条件,也是成功的根本原因。

琵琶考原

透过古代文献一方面考察琵琶及各部位名称的由来，另一方面探求琵琶演奏姿势及奏法的演变进程。

略论我国古代琵琶技巧及衍变

琵琶是我国最主要的民族乐器之一,由古代西亚的"乌德"乐器发展变衍而来。琵琶对世界弹拨乐器演奏法的最大贡献,在于右手以指甲面触弦的弹挑法技巧。

Application of joint elastic impedance inversion in the GD Oilfield

For the complicated reservoir description of the GD oilfield, P-wave and S-wave elastic impedance inversion was carried out using pre-stack seismic data to accurately identify the lithology of the reservoir. The joint inversion was performed using three or more partial stacks to overcome the singularity of post-stack seismic inversion that can not satisfy the requirements of complex reservoir description and to avoid the instability of the inversion result caused by low signal-noise ratio in the pre-stack gather. The basic theory of prestack elastic impedance inversion is briefly described in this paper and, using real data of the GD oilfield, the key steps of angle gather wavelet extraction, horizon calibration, S-wave velocity prediction, and elastic parameter extraction were analyzed and studied. The comprehensive interpretation of multiple elastic parameters determined from log analysis is a key to improving the effect ofprestack seismic inversion.

Optimization of suspension system of heavy off-road vehicle for stability enhancement using integrated anti-roll bar and coiling spring mechanism

Short suspension system has an indispensable effect on vehicle handling and ride,so,optimization of vehicle suspension system is one of the most effective methods,which could considerably enhance the vehicle stability and controllability.Motion control,stability maintenance and ride comfort improvement are fundamental issues in design of suspension system of off-road vehicles.In this work,a dependent suspension system mostly used in off-road vehicles is modeled using Trucksim software.Then,geometric parameters of suspension system are optimized using integrated anti-roll bar and coiling spring in a way that ride comfort,handling and stability of vehicle are improved.The simulation results of suspension system and variations of geometric parameters due to road roughness and different steering angles are presented in Trucksim and effects of optimization of suspension system during various driving maneuvers in both optimized and un-optimized conditions are compared.The simulation results indicate that the type of suspension system and geometric parameters have significant effect on vehicle performance.

Elastoplastic solutions for single piles under combined vertical and lateral loads

In order to improve the reliability of the design and calculation of single piles under the combined vertical and lateral loads, the solutions were presented based on the subgrade reaction method, in which the ultimate soil resistance was considered and the coefficient of subgrade reaction was assumed to be a constant. The corresponding computational program was developed using FORTRAN language. A comparison between the obtained solutions and the model test results was made to show the validity of the obtained solutions. The calculation results indicate that both the maximum lateral displacement and bending moment increase with the increase of the vertical and lateral loads and the pile length above ground, while decrease as the pile stiffness, the coefficient of subgrade reaction and the yielding displacement of soil increase. It is also shown that the pile head condition controls the pile responses and the vertical load may cause the instability problem to the pile. In general, the proposed method can be employed to calculate the pile responses independent of the magnitude of the pile deflection.

Deformation behaviors of 21-6-9 stainless steel tube numerical control bending under different friction conditions

For contact dominated numerical control(NC) bending process of tube, the effect of friction on bending deformation behaviors should be focused on to achieve precision bending forming. A three dimensional(3D) elastic-plastic finite element(FE) model of NC bending process was established under ABAQUS/Explicit platform, and its reliability was validated by the experiment. Then, numerical study on bending deformation behaviors under different frictions between tube and various dies was explored from multiple aspects such as wrinkling, wall thickness change and cross section deformation. The results show that the large friction of wiper die-tube reduces the wrinkling wave ratio η and cross section deformation degree ΔD and increases the wall thinning degree Δt. The large friction of mandrel-tube causes large η, Δt and ΔD, and the onset of wrinkling near clamp die. The large friction of pressure die-tube reduces Δt and ΔD, and the friction on this interface has little effect on η. The large friction of bending die-tube reduces η and ΔD, and the friction on this interface has little effect on Δt. The reasonable friction coefficients on wiper die-tube, mandrel-tube, pressure die-tube and bending die-tube of 21-6-9(0Cr21Ni6Mn9N) stainless steel tube in NC bending are 0.05-0.15, 0.05-0.15, 0.25-0.35 and 0.25-0.35, respectively. The results can provide a guideline for applying the friction conditions to establish the robust bending environment for stable and precise bending deformation of tube bending.

Elastic solutions for partially embedded single piles subjected to simultaneous axial and lateral loading

In order to improve the design level of partially embedded single piles under simultaneous axial and lateral loads, the differential solutions were deduced, in which the soil was treated as an ideal, elastic, homogeneous, semi-infinite isotropic medium. A comparison was made between model test results and the obtained solutions to show their validity. The calculation results indicate that the horizontal displacement and bending moment of the pile increase with increases of the axial and lateral loads. The maximum horizontal displacement and bending moment decrease by 37.9% and 13.9%, respectively, when the elastic modulus of soil increases from 4 MPa to 20 MPa. The Poisson ratio of soil plays a marginal role in pile responses. There is a critical pile length under the ground, beyond which the pile behaves as though it was infinitely long. The presented solutions can make allowance for the continuous nature of soil, and if condition permits, they can approach exact ones.

公路施工土体压实曲线的理论探讨与实际应用

运用土样全压实曲线理论,借助土体强度以及回弹模量的相关实验,探讨了公路施工土样全压实和击实曲线的知识与实际应用的要点,探究了公路应用土体物理属性、压实土体和击实功之间的联系,以为同类工程应用提供技术参考。

Modeling unbalanced rotor system with continuous viscoelastic shaft by frequency-dependent shape function

A reduced-order dynamic model for an unbalanced rotor system is developed, taking the coupling between torsional and lateral vibrations into account. It is assumed that a shaft is regarded as a continuous viscoelastic shaft with unbalanced and small deformation properties. The equations of motion for the torsional and lateral vibrations are derived using Lagrange's approach with the frequency-dependent shape function. The rotor torsional vibration is coupled with the lateral vibrations by unbalance elements in a way of excitations. Simulation and experiment results show clearly that the torsional vibration has strong impact on the rotor lateral vibrations, and it causes subharmonic and superharmonic excitations through unbalance elements, which leads to the superharmonic resonances in the lateral vibrations. This model with low-order and high accuracy is suitable for rotor dynamic analysis in real time simulation as well as for active vibration control syntheses.

Static aeroelastic analysis of a high-aspect-ratio wing based on wind-tunnel experimental aerodynamic forces

The aeroelastic responses of a high-aspect-ratio wing are investigated based on nonlinear experimental aerodynamic forces. The influences of nonlinear experimental aerodynamic forces and dynamic pressures on the wing loads are studied in the longitudinal and lateral maneuver states. The flight loads of the wing fixed at the root are calculated at different angles of attack. The aileron efficiency with respect to the dynamic pressures and aileron deflections are also studied. The results indicate that the flight loads of the wings vary nonlinearly with the angle of attack and dynamic pressure. Due to the high-lift aerofoil, elastic components are a large portion of the wing loads, especially for small angles of attack and high dynamic pressure condi-tions. The aileron efficiency is significantly affected by aileron deflections, dynamic pressures and angles of attack when the nonlinear experimental aerodynamic forces are used for calculation. In states with high dynamic pressures and large aileron deflections, aileron reversal can occur. The aileron deflection and angle of attack have a nonlinear effect on the aileron efficiency. An efficient method for analyzing the flight loads and structural design of high-aspect-ratio wings is derived in this study, and the analysis can provide insight into the distribution of flight loads for high-aspect-ratio wings.

Effect of hydration on the elasticity of mantle minerals and its geophysical implications

Recent studies have shown that major nominally anhydrous minerals in the Earth's mantle, such as olivine, pyroxene and garnet, can incorporate considerable amounts of water as structurally bound hydroxyl. Even a small amount of water is present in mantle minerals, it can strongly affect a number of physical properties, including density, sound velocity, melting temperature, and electrical conductivities. The presence of water can also influence the dynamic behavior, lead to lateral velocity heterogeneities, and affect the material circulation of the Earth's deep interior. In particular, seismic studies have reported the existence of low-velocity zones in various locations of the Earth's upper mantle and transition zone, which has been expected to be associated with the presence of water in the region. In the past two decades, the effect of water on the elasticity and sound velocities of minerals at relevant pressure-temperature(P-T) conditions of the Earth's mantle attracted extensive interests. Combining the high P-T experimental and theoretical mineralogical results with seismic observations provides crucial constraints on the distribution of water in the Earth's mantle. In this study, we summarize recent experimental and theoretical mineral physics results on how water affects the elasticity and sound velocity of nominally anhydrous minerals in the Earth's mantle, which aims to provide new insights into the effect of hydration on the density and velocity profile of the Earth's mantle, which are of particular importance in understanding of water distribution in the region.