直管法兰智能装配装备研究

为了实现直管法兰自动化、智能化装配加工作业,就需要解决法兰取料、法兰双孔正及旋转预转角、直管法兰定位装配等难题.本文首先分析直管法兰装配工艺现状及难点,以及直管法兰智能装配装备需求的主要功能.然后介绍直管法兰智能装配装备的总体方案及基本结构组成.并介绍了直管法兰智能装配的施工流程和装备的信息数据流程.最后,结合某直管法...     

Filter bank based nonlocal means for denoising magnetic resonance images

Image denoising is a classical problem in image processing. Its essential goal is to preserve the image features and to reduce noise effectively. The nonlocal means （NL-means） filter is a successful approach proposed in recent years due to its patch similarity comparison. However, the accuracy of similarities in this algorithm degrades when it suffers from heavy noise. In this paper, we introduce feature similarities based on a multi- channel filter into NL=means filter. The multi-bank based feature vectors of each pixel in the image are computed by convolving from various orientations and scales to Leung-Malik set （edge, bar and spot filters）, and then the similarities based on this information are computed instead of pixel intensity. Experiments are carried out with Rician noise. The results demonstrate the superior performance of the proposed method. The wavelet-based method and traditional NL-means in term of both mean square error （MSE） and perceptual quality are compared with the proposed method, and structural similarity （SSIM） and quality index based on local variance （QILV） are given.     

Genome-wide profiling identifies Saccharomyces cerevisiae response in PKC-SLT2 signaling and glycogen metabolic pathways to antifungal compound calcofluor white

Fungal infection remains a major problem worldwide, yet treatment options are limited owing to the lack of effective drugs, the significant toxicity of available compounds, and the emergence of drug resistance. The low toxicity of calcofluor white （CFW） is an attractive antifungal compound for its known inhibitive effects on trichophyton rubrum and candida albicans growth. However, the efficacy of CFW is limited in most cases. In order to search for effective means to improve its efficacy, using saccharomyces cerevisiae as a model, we have used microarrays to examine the cell＇s response when treated with CFW on the genome scale. We found that both the PKC-SLT2 （i.e, protein kinase C-mitogen activated protein kinase） and the glycogen metabolic pathways are activated upon CFW treatment. These results suggest that the key components in these pathways could be targeted by other drugs to counter the cell＇s compensative response, thus to further substantiate the inhibitive effect of CFW on fungal growth, which may lead to treatment regimens with improved efficacy of this compound in clinical applications.     

船舶螺旋桨机翼型桨叶周围粘性绕流的研究

此研究从N-S基本方程出发,采用亚格子尺度模型,运用大涡模拟方法,通过数值计算研究了船舶螺旋桨机翼型桨叶在低马赫数下的粘性绕流情况,其中包括创建模型、网格划分等,获得了速度场、压力场和涡量场等图像,对减小船舶阻力、降低振动噪声和提高船舶螺旋桨的设计水平具有十分积极的现实意义。     

黄土地铁隧道锚杆布置方式的模型试验研究

文章利用平面应变三向加载装置进行室内模型试验,对无锚杆、全环锚杆和边墙锚杆三种锚杆布置方式进行了对比试验,并参考工程现场测试结果,对系统锚杆在黄土地铁隧道中的作用进行了研究;通过模型试验获得了适合黄土地铁隧道的锚杆相似材料,实现了"先加载,后挖洞"以及锚杆和衬砌联为一体的试验方法。通过对比发现:系统锚杆能较好地控制掌子面周围的塑性区发展;边墙锚杆在隧道洞室开挖支护后能加快围岩应力调整,且能有效改善衬砌的受力情况;综合考虑经济因素,认为边墙锚杆支护系统在浅埋暗挖黄土地铁围岩中加固效果较好,实际施工中应予以保留。     

无水漂卵砾石地层土压平衡盾构施工关键技术

文章以北京地铁九号线丰台东大街站—丰台北路站区间全断面无水漂卵砾石地层盾构掘进工程为背景,基于地质勘查资料和试验探井的分析结果,掌握了该漂卵砾石地层的空间分布规律和力学性质。在合理选用辐条式土压平衡盾构的基础上,通过对盾构机关键部件进行适应性改造,降低了刀盘刀具磨损。施工中通过掘进参数的有效选择,实现了该类型盾构机在全断面卵砾漂石地层中的长距离掘进。     

摩擦摆减隔震支座在高烈度区高架桥的减震效果分析

该文介绍了摩擦摆式支座减隔震工作原理。该类支座减隔震性能主要影响参数为摩擦副的摩擦系数和球面等效曲率半径。为了研究高烈度区该类支座减隔震效果,通过对某高架桥一联3×30m预应力混凝土连续箱梁桥模型的计算分析,得出在不同参数组合下桥梁结构的地震响应,讨论了各参数对结构响应的影响规律,并对工程应用中选取较优的参数提出了建议,为高烈度区修建高架桥梁积累经验。     

城市立交匝道桥下部结构设计要点

与常规桥梁相比,匝道桥的结构和受力具有其特殊性。该文结合某城市立交匝道桥设计实例,对匝道桥下部结构设计要点进行总结,可供同行一起探讨。     

对提高工程预算的编制质量的认识

该文以多年来参加多项施工图预算的编制为背景,对提高工程预算的编制质量有几点体会:除应作好准备工作、熟悉施工图纸、计算工程量及套用定额单价、计算其他各项费用、取费及利税等外,工程预算编制人员应不断提高业务素质,不断积累设计和施工经验,不断与设计人员沟通,现场查勘,才能最终达到提高预算编制质量的目的。其体会可供同行借鉴。     

双曲线法在内蒙古沙漠地区软土路基沉降预测中的应用研究

沉降速率分析成果可用来判别工程的安全和填筑速率的合理性,工后沉降量的分析成果是决定卸载时间的主要依据.文中对双曲线预测模型及原理进行介绍,结合内蒙古沙漠地区乌嘎一级公路路基沉降变形的实例进行分析,得出软土路基沉降的动态变化情况.