文本自动分类技术的研究

文本自动分类方法是指在给定的分类体系下,根据文本的内容自动判别类型的过程。它是当今信息搜索领域的重要研究方向。本文介绍了文本自动分类的研究方法,文本的向量空间模型表示．并给出了文档的训练算法和分类算法。     

山区高速公路涵洞设计方法的探讨

对山区高速公路涵洞设计工作中发现的问题进行了总结,分析了当前涵洞设计方法和理论的不足之处,提出了几点思考和探讨,为完善涵洞设计方法提出了几点建议性补充。     

随机风浪下的游艇稳性可靠度计算

建立游艇横摇运动微分方程,利用马尔科夫过程理论和路径积分法进行求解,得到游艇横摇角概率密度函数。借鉴结构可靠性计算方法建立游艇稳性概率计算模型,采用当量正态化法(JC法)求解得到游艇稳性可靠度。实例计算表明:游艇在不同海域下的稳性可靠度存在一定差异,随着外界风浪增大,游艇稳性可靠度呈逐步下降趋势,且都存在一个快速下降的波高区间。该方法能够更科学地评判游艇在不同航行条件下的稳性状况,是游艇稳性横准研究的发展方向之一。     

船用防污涂料浅海浸泡试验防污性能评价方法

针对防污漆样板浅海浸泡试验防污性评定,通过分析不同类别的生物污损对防污涂料涂层的影响,根据其影响程度的不同划分合适的评分比例,并选取单体污损作为主要评价标尺。参考国标《防污漆样板浅海浸泡试验方法》,结合浅海浸泡试验,在实际运用中发现现行评价体系的不足之处,并提出相应的解决方案,在此基础上建立一套行之有效的船用防污涂料防污性评价方法。     

大深度浮力驱动式水下运载器的浮潜运动研究

基于模型试验,对大深度浮力驱动式水下运载器的上浮运动进行研究与分析,基于数值仿真,提出大深度浮力驱动式水下运载器浮潜运动的快速预报方法,并将预报结果与模型试验结果进行对比,证明快速预报方法的准确性。使用快速预报方法,针对水下运载器比重变化、流体密度变化、水下运载器初速度以及水流扰动4种因素对浮潜运动的影响进行研究.此外,对水下运载器作六自由度运动时所受的水动力进行计算,为后续的六自由度运动预报和研究提供基础。     

玻璃钢防腐蚀材料检测方法

针对海洋环境下混凝土结构易遭受海水侵蚀导致结构破坏、而高性能混凝土等技术措施不能满足高耐久技术要求的现状,采用玻璃钢包覆防腐蚀技术以提高海工混凝土结构耐久性。对玻璃钢包覆防腐蚀材料的原材料和耐久性检测方法进行分析,提出原材料和耐久性检测方法,以利于玻璃钢防腐材料施工质量的控制。     

超临界雷诺数下桥墩紊流宽度的计算方法

桥墩紊流宽度的计算与水流雷诺数的范围关系较大,将影响到计算成果的合理性。结合山区河流超临界雷诺数条件,采用格子Boltzmann方法模拟桥墩三维紊流流场,并结合大涡模拟和运动边界处理方法,分析不同来流、河形等条件下的桥墩三维紊流宽度,由此建立了顺直河道和弯曲河道中圆型桥墩相对紊流宽度与弗劳德数之间的耦合关系。该研究成果通过四川邓家坝大桥航宽验算,与经验法及祖小勇算法比较,发现该方法得出的桥墩紊流宽度略小、其数值趋于合理。     

Model Test on Grouting Law in Dynamic Water-Rich Sand Layers by the Electric Resistance Method北大核心CSCD

In order to study the diffusion law of grouting slurry in the water-rich sand layer under flowing water conditions, a grouting test model consisting of a main test system, a grouting system, and a measurement system was developed. And for detecting the diffusion scope of the grouts, a new resistivity method was proposed. It is found that the relationship between grouting pressure and grouting rate during the test is strong. Under hydrodynamic conditions, the grouting slurry diffuses elliptically. Due to gravity and the effect of the upper water flow, the center of gravity of the ellipsoid is below the grouting outlet, and the grouting effectively improves the physical and mechanical properties of water-rich sand bodies. At the same time, the resistivity method has a good application effect on the detection of grouting diffusion range. The range of slurry diffusion obtained by the resistivity method is basically consistent with the boundary of the stone body after excavation, indicating that the resistivity method is reliable for detection of grouting range in dynamic water-rich sand layer. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Analysis of Ground Response and Structure Stress Induced by PBA Method北大核心CSCD

The application of prefabricated tunnel technology has been become a new research field both in China and abroad. Based on the running tunnel between Yufuhe station and Wangfuzhuang station of Jinan rail transit line R1, a new prefabricated tunnel construction technology, the PBA method is presented. This paper makes a detailed discussion on section form, supporting scheme and construction process of the PBA method. In this study, 3D a new 3D numerical model for PBA method is presented by finite difference numerical simulation software Flac and the construction processes are modeled. The rule of ground surface settlement, ground deformation and structural stress caused by PBA method is studied in detail. Results show that the structure of PBA method can effectively control the deformation magnitude and scope. Stress concentration appears at the prefabricated connection parts and the reinforcement needs to check. The total assembled structure forms the load-bearing system after the completion of the lateral wall. The built-in depth of the precast pile and pile bottom grouting quality should to be ensured to control the displacement of the precast piles. The results of this study will be a useful reference for similar projects in the future. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

逆向支撑底模反吊在水中防撞墩台施工中的应用

在航道整治工程中设置的桥梁防撞墩,由于墩台的底部经常设置在常年平均水位之下,无法按常规方法采用底部模板正向支撑系统施工。通过采用逆向支撑底模反吊方案,将钢木组合整体模板吊装入水,墩台分层浇筑的方式进行施工。该方案无需设置围堰,形成干地施工条件,成功解决水下混凝土浇筑和模板拆除难的问题,也解决通航水域狭小、操作空间有限、保证正常通航的问题,具有施工方便、安全性高、墩台施工精度易于控制的优点。