摘要：This paper aims to address the problem of geometric state control of large-segment steel box girders in offshore hoisting during the construction of large-span bridges. First, the geometric state control indexes of a large-segment steel box girder are determined, such as the manufacturing parameters of the top and bottom slabs, the width of the annular joint, and the support position. Second, the geometric state equations and state transfer matrixes of large-segment steel box girders under different conditions are deduced by taking the mileage and elevation of control points as basic state variables. In application of the geometric state transfer method in the construction control of the Hong Kong-Zhuhai-Macao Bridge, the width of the annular joint and the position parameters for the support of the large-segment steel box girder are predicted precisely. Moreover, the manufacturing parameters of the top and bottom slabs of the steel box girders are calculated reliably. The measured values show that the width of the annular joint is basically the same with the difference of less than 2 mm, the eccentricity of bridge support is less than 20 mm, and the elevation error of the bridge deck is within-10 mm to +15 mm, which meets the construction accuracy. Using the geometric state transfer method, the rapid and accurate installation of the Hong Kong-Zhuhai-Macao Bridge has been realized, demonstrating that the precise control of the geometric state of a steel box girder with ectopic installation and multi-state transition can be realized by using the geometric state transfer method.

摘要：文章采用SDNA构建三维网络分析模型并结合实地调研来量化分析南京工业大学江浦校区的接近度、穿行度等量化量,通过行人计数法收集指定节点在不同时间段的人流数据,进一步运用多元线性回归模型分析空间功能混合度、地形坡度等变量与空间活力之间的关系。据此,指出提升空间可达性、增强空间功能性、促进功能复合化等策略以促进校园空间整体性的活力提升。

摘要：第五次全美数学和科学教育调查展现出科学师资所具有的年龄结构合理、大学课程修习薄弱、专业发展不足等特征;课程实施所具有的课程门类和教材选用多样化、教师教学质量不理想、教育活动较丰富、学生学业负担较小等特征。本文对其师范教育理念与基础教育实践脱节,教师考证、招募设计与学校发展愿景脱节,专业发展投入背离以人为本理念等问题进行了反思。

摘要：西藏高山区中小流域为亚洲众多大河的源区,是国家水资源安全战略基地和水能资源接续基地。然而,本区下垫面情况异常复杂且监测难度大,属典型的无(缺)资料地区,设计洪水计算方法发展缓慢,为当地水利水电项目的规划设计、施工建设和运营管理等带来了较大的风险和挑战。受水文观测资料、高度复杂的下垫面情况及暴雨洪水形成机制等制约,现有方法(如推理公式、洪水频率分析及水文比拟等)在西藏高山区的适用性和有效性不足。为解决西藏中小流域设计洪水计算的难题,建议通过数学物理途径推导流域关键带结构信息(如地形—植被—土壤)与径流响应的解析关系,进而建立由下垫面信息反演设计参数及洪水设计值的理论方法,发展适合西藏中小流域地理水文特性的新型设计洪水计算方法。

摘要：人工模拟降雨能够消除无关因素的干扰，缩短试验周期、克服试验场地限制并加速雨水入渗过程，有利于根据研究需要模拟雨强、坡度等试验条件，同时节省时间和精力。人工模拟降雨装置因其便捷简单的特性被广泛应用于各种领域的试验研究中，早在上世纪60年代，就已经开始被各国采用。根据不同试验的需求，可以通过设计和改造模拟降雨装置，有效地控制降雨，从而使相关试验顺利进行。笔者根据目前降雨装置的发展状况，整理国内外不同类型的人工模拟降雨装置，根据室内和室外人工降雨2个角度对降雨装置进行分类与归纳，提出降雨装置的评价标准，并对其功能和应用进行详细的比较与分析，根据存在的缺点和不足为其未来发展提出建议。

摘要：How to directionally design the hollow zeolite via a green route is of great significance. Here, we successfully synthesized the hollow Fe-silicate-1 encapsulated ultra-small Fe_(2)O_(3) nanoparticles (2.5 nm) with higher yield (85.2%) by mother liquid than traditional dissolution-recrystallization for the first time, which was achieved by precisely regulating the number and distribution of defects in zeolite and cleverly utilizing the TPAOH and nuclei in mother liquor. The effects of synthetic temperature, synthetic period and addition amount of parent zeolite on the formation of hollow zeolite have been investigated and the effect of synthetic conditions on the defects in parent zeolite has been also firstly quantified. The corresponding formation mechanism has been proposed. The abundant inner defects provided by the zeolite synthesized at 130 °C for 1 day and large amount of TPAOH remaining in mother liquid are conducive to the formation of hollow zeolite. Meanwhile, both parent zeolite and nuclei (4-, 5-member rings and structure units) in mother liquid obtained at 130 °C play the crucial roles in enhancing the zeolite yield. Notably, Fe_(2)O_(3) nanoparticles could decompose into small fragments by the interaction with nuclei in mother liquid. Partial ultra-small Fe_(2)O_(3) nanoparticles would be encapsulated in cavity and the rest could be inserted in the zeolite framework, which is significantly different from the conventional dissolution-recrystallization mechanism. The obtained encapsulated catalyst shows the superior catalytic performance and stability in phenol and tetracycline degradation reactions.

摘要：介绍了《机械制造基础》多媒体课件的设计过程以及运用多媒体著作工具Ａｕｔｈｏｒｗａｒｅ进行软件系统开发的方法。文中给出了其中一个知识点的设计实例。

摘要：为解决当前基于深度学习的森林火灾探测算法存在结构复杂、规模庞大,且难以兼顾检测精度和效率的问题,提出一种基于YOLOv5s的轻量化森林火灾探测算法。首先,采用优化的背景差分技术消除背景图像中类火物体的干扰,减少分析图像所需的时间;其次,设计分组混洗策略优化常规卷积,并在特征提取的C3模块中融入高效通道注意力(ECA)机制和深度可分离卷积,增强图像特征提取与融合能力的同时有效降低模型的参数量;然后,采用动态非单调聚焦机制优化Wise-交并比(WIOU)损失函数,减少低质量样本产生的有害梯度;最后,在构建的森林火灾数据集上将所提算法与其他算法做充分的试验对比。结果表明:所提算法在各类场景均展现出良好的泛化性,对火焰目标的检测精度达到86.1%,较标准YOLOv5s检测精度提升2.7%,检测速度提升11.4%,有效降低了火灾误报率,增强了模型的检测性能。

摘要：文章聚焦于共享单车搬运领域面临的现状与挑战,提出了一种新型搬运载具方案,并基于动力学仿真对其进行结构设计。文章首先分析了共享单车搬运过程中存在的难点,以及当前搬运方法在效率与成本方面存在的问题,进而阐述了新型载具的设计理念及其应用价值。借助CATIA软件,构建了精确的三维模型,并在Adams环境中进行了动力学仿真,模拟了载具在平面行驶、过坑、过坎等多种复杂工况下的运动状态。随后,使用动力学载荷在Abaqus中进行应力应变分析,并对载具进行了优化设计。

摘要：Calculating the flow coefficient of a spool-valve is complicated due to the coupling–throttling effect in the throttling grooves of a proportional–directional *** this paper,a methodology for expressing the flow coefficient of coupled throttling grooves is proposed to resolve that *** this purpose,an approach of a 3 D numerical simulation and an experimental bench were introduced based on the prototype of a commercial proportional *** results show consistency between the numerical simulation and the bench *** on that,the concept of‘saturation limit’is introduced to describe the value gap between the current and saturated flows,so that the flow-coefficient saturation limit of the prototype in the process can be ***,an approximate flow coefficient suitable for coupled throttling grooves within finite variable space,which is based on three typical throttling structures(i.e.O-shape,U-shape,and C-shape)of the coupled throttling grooves,is obtained based on an orthogonal *** model results are consistent with the numerical and experimental results,with maximum errors of less than 5.29%and 5.34%,*** suggests that the proposed method is effective in approximating the flow coefficient.