Free-Edge and Ply Cracking Effect in Angle-Ply Laminated Composites Subjected to In-Plane Loads

This paper presents a semianalytical method for the prediction of interlaminar stresses and displacements near the free edges and ply cracks in general angle-ply laminates subjected to biaxial extensions and/or in plane shear deformation. The method is based on a state space representation of the three-dimensional equations of elasticity. Numerical solutions are obtained by using layer refinement in the through thickness direction and Fourier series expansion in the other directions. By this approach, an angle-ply laminate may be composed of an arbitrary number of monoclinic layers and each layer may have different material property and thickness. This method guarantees continuous fields of all interlaminar stresses across interfaces between material layers. Numerical results are compared with those obtained from other methods. It is found that the theory provides a satisfactory approximation to the stress singularities near the free edges and ply cracks. Numerical solutions for antisymmetric laminates under extension and general laminates under shearing are new in the literature and can be used as benchmarks for validating new models.     

安棚深层系凝析气井射孔压井液技术研究

介绍了一种保护油气层的射孔压井液技术，该技术所用的配方具有低密度，低表面张力且具有较强的防膨能力等特点，在安棚深层系低孔低渗油田安3003等凝析气井作业中现场试验，解决了安棚深层系低压气井的水锁伤害等问题，对低孔低渗油气田作业入井流体的研究与应用具有较好的借鉴意义。     

链烷烃的表面张力与内压

对Ｄａｖｉｓ和Ｒｏｓｓｅｉｎｓｋｙ提出的关系检验表明，液体的表面张力σ与Ｐ１Ｖｍ１／３之比不仅取决于温度，还与液体的种类有关，据此，建立了一个能由链烷烃的分子结构准确预测其表面张力的方法。     

用Promax处理LD22-l“模糊带”地震资料

通过LD22-l构造地震资料目标处理,搞清了“模糊带”,引进交互处理系统是成功的.     

Long-term observation of subcutaneous tissue reaction to synthetic auditory ossicle (Apaceram) in rats

The present study evaluates histological characteristics of the soft tissue response to long-term implantation of Apaceram discs composed of dense hydroxyapatite in rats. Discs were implanted into the subcutaneous tissue of 76 rats for six to 20 months. Decalcified histological sections stained with haematoxylin and eosin (H & E) and Mallory's azan were examined. Different cell types surrounding implants were counted. The greatest proportion of macrophages was found at six months (13.5 per cent). This proportion gradually decreased to four per cent at 20 months. Small numbers of lymphocytes and foreign body giant cells were observed in every group, but neither neutrophils nor osteogenesis were observed in any specimens. Results of the present study and previous related studies indicate that despite reappearance of a small number of macrophages six months after implantation, Apaceram is useful for reconstructive surgery.     

铁钴钒软磁合金损耗谱的分形结构

研究了铁钴钒软磁合金的铁芯损耗，发现铁芯损耗谱具有分形结构。讨论了带材厚度和磁感应强度对分形维数Ｄｆ的影响。     

室温下Ho∶YAG激光器输出3J的2．1μm激光

根据对２．１μｍ波长Ｃｒ，Ｔｍ，Ｈｏ∶ＹＡＧ激光器的实验研究，详细分析了冷却温度、放电脉冲半宽度和输出镜透过率等因素对激光器的输出的影响     

Testing of multi-output circuits by means of signature analyzer

Let a circuit havem outputs,m>1. There are two ways to test this circuit by means of a signature analyzer: use a single input analyzer for each output or use anm-input analyzer to test all outputs simultaneously. The main goal of this letter is to demonstrate that for fault output sequences with small multiplicity of errors and long length the second approach is more effective.     

A damage identification technique for CF/EP composite laminates using distributed piezoelectric transducers

In this study, a damage identification approach was developed for carbon fibre/epoxy composite laminates with localized internal delamination. Propagation of the Lamb wave in laminates and its interaction with the delamination were examined. The fundamental symmetric Lamb wave mode, S₀, and the lowest order shear wave mode, S₀^′, were chosen to predict damage location. A real-time active diagnosis system was therefore established. This technique uses distributed piezoelectric transducers to generate and monitor the ultrasonic Lamb wave with narrowband frequency. The two-way switches were employed to minimize the number of transducers. A signal-processing scheme based on the time–frequency spectrographic analysis was utilised to extract useful diagnostic information. Also, an optimal identification method was applied on damage searching procedure to reduce errors and obtain the diagnostic results promptly. Experiments were conducted on [0/−45/45/90]_s CF/EP laminates to verify this diagnosis system. The results obtained show that satisfactory detection accuracy could be achieved.     

GH2027铁基高温合金的第二相研究

运用电子显微分析和波谱分析等方法对ＧＨ２０２７合金的第二相进行了研究，结果表明，合金晶界相主要是片状Ｍ６Ｃ和薄膜状Ｍ２３Ｃ６，经波纹图样测得其错配度约为３％，晶内Ｍ６Ｃ和Ｍ２３