作大范围运动的空间桁架结构动力分析

作高速大范围运动的弹性体，由于运动和变形的耦合将产生动力刚化现象，传统的动力学理论难以计及这种影响。本文在有限元方法中首次引入了单元耦合形函数（阵），以此将单元弹性位移表示为单元结点位移的二阶小量形式。利用几何非线性的应变－位移关系式，在小变形假设条件下确定了单元耦合形函数。在此基础上，根据Ｋａｎｅ方程，运用模态坐标压缩，并通过适当的线性化处理，得到了一致线性化的动力学方程。编制了计及动力刚化的空间桁架结构有限元分析程序。仿真算例的计算结果验证了理论和算法的正确性     

TiAl＋Sb合金的热稳定性的研究

研究了退火处理对Ｔｉ－３４ｗｔ．％Ａｌ－０．５ｗｔ．％Ｓｂ合金的室温抗弯性能，显微组织，相组成和断口形貌的影响。发现，低于１０００℃退火处理，ＴｉＡｌ＋Ｓｂ合金的显微组织没有变化，其力学性能仍然保持较高的值。此合金成分适应高温使用条件。     

炸药压装爆炸事故剖析

文中依据压爆事故的实例，对其产生的原因做了剖析，在剖析的基础上对压爆机理做了简要的阐述并提出了相应的预防措施。     

光纤模式噪声的研究

综述了光纤模式噪声的产生、计算，并介绍了减小它的一些方法。     

A monitoring, feedback, and triggering system for reproducible breath-hold MR imaging

OBJECTIVE: To evaluate the diagnostic accuracy and clinical usefulness of high-resolution transvaginal duplex Doppler ultrasound in postpartum and post-abortion patients with excessive hemorrhage who are suspected of having residual trophoblast. METHODS: Forty-eight women with excessive hemorrhage referred for possible residual trophoblastic tissue were evaluated by transvaginal duplex Doppler ultrasonography. Based on two-dimensional imaging, the patients were divided prospectively into groups: women who had an empty uterus with a normal uterine cavity, those with a pure endometrial fluid collection and no echogenic foci, those who had a mixed endometrial fluid collection with foci of echogenicity, and those with intracavitary heterogeneous material with mixed echo patterns of fluid and solid components. In each group, Doppler studies were performed and the resistance index (RI) was calculated. The two-dimensional patterns and Doppler results were correlated with clinical and pathologic follow-up. RESULTS: Twenty-eight subjects had a normal uterine cavity and seven had a pure endometrial fluid collection; all were treated conservatively and none showed later clinical evidence of residual trophoblastic tissue. In 13 women, residual trophoblast was strongly suggested from the images of two-dimensional ultrasonography: Five showed an endometrial fluid collection with some echogenic foci, and eight exhibited intracavitary mixed echogenic material. All underwent curettage, and residual trophoblastic tissue was found in ten of the 13. The mean (+/- standard deviation) RI to flow in the myometrial arteries was 0.54 +/- 0.15 in women without residual trophoblast and 0.35 +/- 0.1 in those with residual trophoblastic tissue (P < .01). CONCLUSION: Our experience suggests that transvaginal duplex Doppler ultrasonography is an effective noninvasive method for evaluating patients with excessive postpartum and post-abortion hemorrhage who are suspected of having residual trophoblastic tissue. Its use enhances the positive preoperative diagnosis of residual trophoblastic tissue and may reduce unnecessary curettage procedures.     

A branch and cut algorithm for the VRP with satellite facilities

An important aspect of the vehicle routing problem (VRP) that has been largely overlooked is the use of satellite facilities to replenish vehicles during a route. When possible, satellite replenishment allows the drivers to continue making deliveries until the close of their shift without necessarily returning to the central depot. This situation arises primarily in the distribution of fuels and certain retail items. When demand is random, optimizing customer routes a priori may result in significant additional costs for a particular realization of demand. Satellite facilities are one way of safeguarding against unexpected demand. This paper presents a branch and cut methodology for solving the VRP with satellite facilities subject to capacity and route time constraints. We begin with a mixed-integer linear programming formulation and then describe a series of valid inequalities that can be used to cut off solutions to the linear programming relaxation. Several separation heuristics are then outlined that are used to generate the cuts. Embedded in the methodology is a VRP heuristic for finding good feasible solutions at each stage of the computations. Results are presented for a set of problems derived from our experience with a leading propane distributor.     

热浸镀铝护栏的生产工艺研究

热浸镀铝护栏的生产通过除油→除锈→烘干→热浸镀→精整等过程完成，最佳热浸镀温度为７３０～７５０℃，保温时间３～８ｍｉｎ，护栏提升速度１ｍ／ｓ     

Induction of superoxide dismutase isozymes by tumor necrosis factor-alpha and lipopolysaccharide in cultured normal and hyperplastic gingival fibroblasts

We studied 722 reexcision scars of benign and malignant lesions (except melanocytic lesions) excised over a 24-month period. The formalin-fixed, paraffin-embedded tissue sections were examined histologically and immunohistochemically. The histological features of melanocytic hyperplasia were present in 59 cases (8%), 56 from the sun-exposed skin of the face and neck and three from the trunk [p < 0.00001]. The most common sites were the nose and lower eyelids, but the forehead was also frequently involved. Of the 59 patients, 41 were women (p < 0.0001). Basal cell carcinoma was the most frequent original lesion in both sexes (80%). No melanocytic hyperplasia was found in 663 cases (298 on the trunk and extremities and 365 on the head and neck). We have seen this reaction pattern following reexcision of melanocytic lesions as well. Thus, interpreting reexcision margins when lentigo maligna or similar lesions are reexcised may be fraught with difficulty. It is important for pathologists and dermatopathologists to recognize this phenomenon because histologically the presence of increased numbers of large melanocytes could be misinterpreted as melanoma in situ.     

Experiment investigations of millimeter-wave grating spectrometer

The lateral shift of focus diffracted and reflected beam and resolving power, insertion loss of a five channel grating spectrometer for 25 to 100 GHz are experimentally investigated. And some analysis for these results are also given.     

无机添加剂的浓度及pH值对纺锤形α－Fe_2O_3晶貌的影响

本文以高浓度Ｆｅ３＋盐溶液为原料，采用沸腾回流的强迫水解法研究了无机添加剂浓度及反应液初始ｐＨ值对产物纺锤形α－Ｆｅ２Ｏ３晶貌的影响。结果表明，添加剂浓度和反应液初始ｐＨ值对纺锤形α－Ｆｅ２Ｏ３的轴比具有明显的影响，并且当添加剂浓度增加到一定值时，纺锤形α－Ｆｅ２Ｏ３出现解体。