焊接节点构造细节的低周疲劳试验研究

为了研究Q235低碳素钢平板对接焊接试件以及十字型承载V型坡口焊接试件的低周疲劳行为,采用等幅应变控制法对24个试件在不同塑性应变幅下的超低周疲劳性能进行了测试,拟合得到了两类焊接构造细节试件的疲劳寿命S-N曲线,并将测试结果与国际焊接协会发布的疲劳设计规程中同类焊接构造细节的S-N曲线进行对比.结果表明:平板对接焊接试件与十字型承载V型坡口焊接试件的裂纹起源不相同;在超低周疲劳范围内,两类焊接材料的损伤破坏主要包括材料延性损伤和循环疲劳损伤,比国际焊接协会中相同疲劳构造细节的高周疲劳寿命S-N曲线预期的疲劳强度更低,表现出更低的疲劳寿命.     

DNA details

Handy helpers in this week's issue include a dual-purpose device for vertical electrophoresis and electroblotting, a triple-tray gel box and news of a new patent sequence data bank.     

一维经验模态分解在二维图像细节提取中的应用

提出了将一维经验模态分解(1D-EMD)应用到二维图像细节提取的方法.运用1D-EMD方法从水平方向和垂直方向分别处理二维图像,采用最小尺度对齐的原则,可以得到二维图像在水平方向和垂直方向的细节.最后将这2个方向的细节叠加,就可以提取出图像的细节信息.仿真结果证明了该方法的有效性.     

必须重视的表现——建筑细部

文章通过对一些经典的建筑的分析和论述来强调建筑细部在建筑设计中的重要性,并试图对建筑细部设计的一些影响方面进行了试探性的讨论。以此来强调建筑细部对于审美、经典的表现。     

前抛实心球最后用力阶段需注意的技术细节

为进一步改进和完善学生前抛实心球的技术,提高投掷远度,运用文献资料法、观察法、教学实践法,对原地正面前抛实心球最后用力阶段技术细节进行研究分析,具体从通过两脚的落位要便于用力、超越器械时需注意的技术细节、最后用力时髋关节的移动幅度等方面来加以说明.     

Micro-computed tomography for small animal imaging: Technological details

The high-resolution micro-computed tomography （micro-CT） system has now become an important tool for biological research. The micro-CT system enables a non-invasive inspection to screen anatomical changes in small animals. The promising advantages include high-spatial resolution, high sensitivity to bone and lung, short scan time and cost-effectiveness. The dose received by the small animal might be a critical concern in the research. In this article, the choice of the components, fundamental physical problems, the image reconstruction algorithm and the representative applications of micro-CT are summarized. Some results from our research group are also presented to show high-resolution images obtained bv the micro-CT svstem.     

Micro-computed tomography for small animal imaging:technological details

The high resolution micro-computed tomography (micro-CT) system has now become an important tool for biological research. The micro-CT system enables a non-invasive inspection to screen anatomical changes in small animals. The promising advantages include high spatial resolution, high sensitivity to bone and lung, short scan time and cost-effectiveness. The dose received by the small animal might be a critical concern in the research. In this article the choice of the components, fundamental physical problems, the image reconstruction algorithm and representative applications of micro-CT are summarized. Some results from our research group are also presented to show high-resolution images obtained by the micro-CT system.     

大地形三维实时系统多层细节与多样化表现

探讨了应用不同精度DEM生成嵌套地形的方法,并通过共享公共边界的方式解决地形层次细节间的无缝连接问题.同时研究了通过纹理替换来实现三维虚拟环境下不同专题图的动态切换的方法.     

一种与亮度细节相关的图像质量评价方法

由于图像质量取决于主观视觉标准,基于HVS模型分析图像质量的方法,逐步成为图像质量评价的一个新的活跃研究方向。文章基于JND思路,采用建立正交变换库的方法,将图像划分为不同的频带,获取对应频带下的亮度细节视觉阈值,建立亮度细节损伤因子,确定与图像亮度细节相关的质量评价方法;实验方法扩展了视觉多通道特性的分析方法,对应正交变换亮度细节视觉阈值的结果,可以提供图像质量评价参考使用。     

Characterization of the structural details of residual austenite in the weld metal of a 9Cr1MoNbV welded rotor

The existence of residual austenite in weld metal plays an important role in determining the properties and dimensional accuracy of welded rotors. An effective corrosive agent and the metallographic etching process were developed to clearly reveal the characteristics of residual austenite in the weld metal of a 9Cr1MoNbV welded rotor. Moreover, the details of the distribution, shape, length, length-to-width ratio, and the content of residual austenite were systematically characterized using the Image-Pro Plus image analysis software. The results revealed that the area fraction of residual austenite was approximately 6.3% in the observed weld seam; the average area, length, and length-to-width ratio of dispersed residual austenite were quantitatively evaluated to be (5.5 ± 0.1) μm2, (5.0 ± 0.1) μm, and (2.2 ± 0.1), respectively. The newly developed corrosive agent and etching method offer an appropriate approach to characterize residual austenite in the weld metal of welded rotors in detail.     

谈高校校园环境建设的细节管理

校园环境不仅是学校的形象、标志和招牌，还对师生员工的工作、学习、生活有着不可忽视的影响力。在高校校园环境建设中，重视一些细节的管理，将有助于构建和谐、优美的校园环境。     

近代中国西方古典建筑的细部分析

近代中国西方古典形式的建筑异常丰富，多变的细部表现是一个重要因素。这些形式中包含了它特有的细部特征，它既有自己一定的细部法则，也反映了中西融合与变异的历史背景，同时还带有装饰与象征的效果，在细部做法中，折中形式较之正统古典手法有着更多的应用，其中，巴洛克和洛可可成为中国工匠折中处理的主要素材。这应归因于这两种形式与中国传统文化的相通以及当时的社会风尚，折中建筑出现的意义还在于它取代了传统官式建筑而成为新兴官僚身份的象征，同时也反映出民众从伊洋到崇洋的社会心理变化过程。