不同应力状态下裂隙岩体水力劈裂试验研究

以水泥砂浆作为类岩石材料,采用水-固-热耦合试验系统、电液伺服万能试验机、动态数据采集分析系统以及自主设计研制的高压水密封装置分别进行了不同注入流量条件以及单轴压应力作用下裂隙岩体水力劈裂试验。研究结果表明:无轴向拉压作用下,注入流量越大,试样劈裂破坏历时越短,越容易发生劈裂破坏,且试样水力劈裂起裂水压与劈裂水压的比值Pini/PIc与注入流量呈线性关系;注入流量不变的情况下,垂直裂缝走向的轴向压应力对试样水力劈裂起抑制作用,平行裂缝走向的轴向压应力较小时(0.1~0.3 MPa)对砂浆试样水力劈裂起抑制作用,较大时(0.4~0.5 MPa)对砂浆试样水力劈裂起促进作用。     

Piezoelectric behavior of wood under combined compression and vibration stresses I: Relation between piezoelectric voltage and microscopic deformation of a Sitka spruce (Picea sitchensis Carr.)

This study investigated the relation between piezoelectric behavior and the deformation of trachieds in real time under combined compression and vibration stresses. Scanning electron microscope images were recorded directly into a video recorder. Two types of microscopic destruction were observed in the specimens. With the first type, although a small uprush around the boundary of the annual ring was observed, the specimens were broken only by shearing fracture in the 45° direction. With the second type, the specimens were finally broken by shearing fracture after repeated buckling. In these cases the piezoelectric voltage increased almost linearly in the elastic region, proceeded to the maximal point, and then decreased gradually. Finally a clear peak appeared in the buckling and shearing fracture. There is a curved relation between the specific gravity and the piezoelectric parameter when the influence of voids is considered, and there is a linear relation between the dynamic Young's modulus and the piezoelectric parameter when the stress is considered.Part of this paper was presented at the 46th annual meeting of the Japan Wood Research Society in Kumamoto, April 1996     

农业机械的低周疲劳寿命分析方法研究

对农业机械中低周疲劳情况及对农业机械寿命估算的必要性进行了分析,叙述了各种低周疲劳寿命分析的基本方法和一些特殊模型及这些模型的计算公式.所论述的几种疲劳寿命模型具有易懂、简捷及广泛的工程应用前景.     

泄流坡滑坡变形特征及成因分析

泄流坡滑坡位于甘肃省舟曲县境内的白龙江左岸,滑体长２ ６００ ｍ ,总体积约５ ０００ 万ｍ３ ,为一典型的断裂带滑坡。２０ 世纪以来该滑坡曾发生８ 次滑动,滑体明显分为上下两段,目前总体上滑体仍处于匀速滑动状态,日平均滑动达２０ ｍｍ 以上,局部滑动活跃。滑坡变形主要受新构造运动、地震活动、断裂破碎带、软弱地层影响,同时受降水、江水冲淘和人类活动作用。有关部门应加大投入对该滑坡进行治理,以保证人民生命财产安全。     

针刺联合康复训练对髌骨骨折内固定术后患者膝关节活动度及相关功能的影响

目的 观察针刺联合康复训练对髌骨骨折内固定术后患者膝关节活动度及相关功能的影响。方法 选取本院康复科收治的78例髌骨骨折内固定术后患者,按照随机数字表法将患者分为观察组和对照组,每组39例。对照组给予早期康复治疗,观察组在对照组的基础上给予针刺治疗,观察治疗前后两组患者的膝关节活动度、Bostman膝关节评分以及治疗后的WOMAC骨关节炎指数评分、临床疗效。结果 （1）治疗后两组患者的膝关节活动度、Bostman膝关节评分均较治疗前升高（P<0.05）,且观察组高于对照组（P<0.05）;（2）治疗后观察组的疼痛、关节功能评分及WOMAC总分均低于对照组,差异有统计学意义（P<0.05）;（3）治疗后观察组患者的优良率为89.74%,对照组为74.36%,两组比较差异有统计学意义（P<0.05）。结论 针刺联合康复训练治疗髌骨骨折内固定术后患者,可提高膝关节活动度、减轻膝关节疼痛并且恢复膝关节功能,疗效优于单纯康复训练,值得推广。     

Fracture Occurrence Mechanism and Control Measure Research of Generator and Compressor Bracket

During a minibus's practical road driving and engine test rig test for vehicle and engine reliability, the phenomenon of generator compressor bracket fracture appears and leads the generator compressor crankshaft belt rupture. It seriously affects the vehicle's operation performance. The article carries through engine test rig test and analysis, using frequency and spectrum technology to identify the bad vibration source combining FEA. It also researches vibration's occurrence, formation, propaganda and fracture mechanism. Based on this, the authors put forward countermeasure, which improves the dynamic characteristic of the system, decreases the vibration intensity and avoides the fracture of bracket and belt.     

Internal fracture fixation

Over the past decade, many improvements to small animal internal fracture fixation have been developed, including improved fixation techniques and a more diverse selection of implants. The understanding that appropriate fixation selection is based on a plethora of biologic, mechanical, and clinical factors has also emerged. Classically, the methods of internal fracture fixation have used pins, wires, screws, and plates to rigidly stabilize fractures that have been anatomically reduced with significant disruption to the biologic fracture environment. Newer methods attempt to minimize trauma to the soft tissues surrounding a fracture and promote biologic osteosynthesis using such implants as interlocking nails and plate-rod fixations. This review provides an overview of both the traditional and current principles of small animal internal fracture fixation.