FE-SEA方法在平台支持船噪声预报中的应用

平台支持船由于作业需要通常配备有动力定位系统,其在侧推工况下舱室噪声超标较为严重。针对这个问题采用计算流体力学(CFD)方法,得到侧推螺旋桨作用在导管上的脉动压力,并将时域计算结果转换成噪声计算的激励条件。采用有限元(FE)与统计能量分析(SEA)混合方法建立船体中频段FE-SEA耦合模型并建立船体高频段SEA模型,对某65 m AHTS船侧推工况下全频段(63 Hz~8000 Hz)舱室噪声进行预报,分析该船噪声分布规律及主要影响因素。并建立起全船的SEA模型,在中频段对比SEA与FE-SEA两种方法得到的舱室声压级频谱曲线,验证了使用混合模型的必要性。     

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 72B线材在绕簧过程中发生了断裂现象。利用金相显微镜对断口附近的金相组织、非金属夹杂物和表面形貌等进行了分析。结果表明：钢丝表面有损伤，且损伤部位出现横向裂纹和形变马氏体，这是导致绕簧过程中发生断裂的主要原因。针对断裂产生的原因，提出具体的改进措施。     

Micromorphology,pharmacognosy, and bio‐elemental analysis of an important medicinal herb: Verbascum thapsus L.

The present study was conducted on characterization of morpho‐anatomical, phytochemical, and bio‐elemental analysis of root, stem, and leaf of Verbascum thapsus. Morphologically Verbascum is a biennial plant that flowers for a month and a half in mid‐ to late summer. Various organoleptic features of root, leaf, and stem were recorded. Anatomically the T. S of the root, stem, and leaf showed a typical dicot histological differentiation. Leaf possessed anomocytic stomata, crescent shape vascular bundles, and covered with long and stellate type trichomes while, stem contained collateral type of vascular bundles and a well‐developed pith to store phytochemicals responsible for various pharmacological activities. The powder drug study through scanning electron microscopy revealed the presence of various types of tissues. Branched, tree like and stellate trichomes in root and leaf help in absorption and reduce loss of water. These anatomical features are responsible for the survival of the plant as biennial. Four macro elements (Na, K, Ca, and Mg) and seven microelements (Cr, Cu, Fe, Mn, Ni, Zn, and Cd) and their concentrations in ppm were also studied using Atomic Absorption Spectroscopy. Phytochemical screening of methanolic extract showed existence of various secondary metabolites, while mucilage and anthraquinones was not detected. The present study helps to understand the taxonomic identification of the plant based on morpho‐anatomical features and throws the attention of the researchers to carry out the work for developing its various formulations, which can ultimately be beneficial for the human beings as well as animals.     

钢管混凝土核心柱轴压组合性能分析

对于钢管混凝土核心柱,核心钢管混凝土和外围普通混凝土的受压性能存在明显差异,本文分析了外围混凝土体积配箍率等因素对柱协同工作的影响,推导出了临界状态时外围混凝土柱的配箍率,并与试验值进行对比,吻合良好。     

模拟高拱坝施工期横缝工作性态的接触-接缝复合单元

考虑施工期高拱坝横缝的真实工作性态以及影响横缝开合度的各种因素,提出一种新的非线性接触-接缝复合单元,该单元可以模拟横缝在灌浆过程中的变形和受力状态上的转化规律,并导出横缝灌浆时刻复合单元的具体转化格式,详细介绍接触-接缝复合单元的数值实施步骤,编制数值程序。小湾高拱坝横缝开合度的数值仿真模拟计算结果表明了该复合单元的可行性和实用性。     

砖混结构住宅楼群整体移动工程的设计与施工

砖混结构具有自重大和抗裂性差等特点。在整体移动的过程中,由于行走基础与老基础以及在建筑物移动方向的前部和后部沉降量的差异,容易导致建筑物在移动过程中开裂甚至破坏。结合郑州某小区7栋砖混结构住宅楼整体移动工程,对其设计与施工中的主要问题开展了讨论。工程每栋建筑物需经历纵向平移、旋转、横向平移和提升过程,克服了该工程建筑体量大、移动距离远、工艺复杂和地质条件差等困难,并根据其受力和变形特点,提出了行走梁和基础设计的原则。     

一种剪切波锤附加装置的研制

本文介绍一种改善剪切波锤使用性能的附加装置。通过本装置的使用可使剪切波锤性能大幅度提高。     

随机振动激励法的应用——测定高灵敏度传感器横向振动特性

本文提出了一种评定传感器技术指标的较好的方法。此方法较之以往采用的正弦或正弦扫频激励法具有明显的优点,可以满足传感器生产现场的需要。本文最后给出了实例。     

小芯样检测高温后混凝土抗压强度的试验研究

主要介绍了采用直径４５ｍｍ和７０ｍｍ小芯样抗压及横劈法对高温后混凝土抗压强度进行检测的试验研究，并用数理统计的方法对得到的测强方程和回归曲线进行了定量的分析。