浅淡外墙干挂花岗岩饰面施工

文章主要介绍外墙干挂花岗岩饰面的设计与施工，阐明干挂花岗岩饰面中主龙骨的设计，龙骨、面板等材料的选材和施工，细部节点做法及质量通痛的防治措施。成品的保护与维护。     

基于分布控制的嵌入式步进电机控制器

分析了步进电机常用的控制方式从分布控制的思想出发提出了步进电机的嵌入式控制器的设计方法并进行了相应的软硬件设计     

Effect of experimental methodology on the JND of the black level for natural images

Abstract— The effect of experimental methodology on the Just Noticeable Difference (JND) of the black level (BL) is assessed using a set of representative natural images. Two methodologies, known in psychophysics to determine JNDs, are mutually compared: an adapted method of adjustment with a same‐difference task and a one‐up‐two‐down staircase method with a two‐alternative forced‐choice task. Thus far, the literature has shown contradictory results for which of the two methods yields the lower difference thresholds. Experimental results show that the second method yields lower JNDs, but is slightly less efficient. Based on this second method, it was found that the JND of the BL for natural images ranges from 0.2 to 1.0 cd/m², varying with image content significantly.     

土钉墙支护在乐滩水电站工程左岸坝段基础边坡支护的应用

针对乐滩水电站工程左岸挡水坝段基坑边坡特点，采用土钉墙支护形式，解决了左岸挡水坝段基坑快速形成和不阻断开挖坡顶施工干道交通问题，积累了土钉支护方式的设计和施工经验。     

基于CA-ResNet50的轮胎激光散斑图的分类研究

针对轮胎激光散斑图识别精度低的问题，本文提出了一种新的轮胎激光散斑图分类网络(CA-ResNet50)。首先选用ResNet50为基础的残差网络，改变传统ResNet50网络模型中的残差块结构，最大程度发挥批标准化的作用；再引入轻量级的卷积注意力模块，增强网络模型对轮胎缺陷的特征提取能力；然后，用LeakyRelu激活函数代替Relu激活函数，解决神经元的“失活”问题；最后，对训练数据集进行扩展，以克服训练中数据量不足和网络模型拟合过度的问题。将本文中提出的CA-ResNet50与当前常用的分类网络模型在相同的数据集上进行对比，实验结果证明本文所提网络模型对轮胎激光散斑图的测试精度高于其他网络，识别精度可达到99.7%。     

主流风淋室现状与新型H系列风淋室

分析国内主流风淋室的现状，概括国内风淋室的分类和使用，并指出现在使用风淋室的优缺点。针对这些优缺点，研究开发出新型风淋室——H型风淋室。     

汽车座椅调整机构的改进与试验

为提高行车人员的安全性,将现有的汽车座椅与底盘的刚性固定改为弹性固定,即将汽车座椅固定于活动底座上,活动底座与汽车底盘靠刚度足够的螺旋拉伸(汽车纵向)弹簧和压缩弹簧(横向)固定.介绍了弹簧参数的计算与确定,并进行了模拟试验.     

Polychromatic light‐emitting conjugated polymer prepared by controlling its structure through active free radical addition

BACKGROUND: The HOMO–LUMO energy level width of conjugated polymers can be manipulated by controlling the conjugation length of the polymeric materials in order to adjust their properties in terms of emission of different colors and realize polychromatic displays. In the work reported in this paper azobisisobutyronitrile (AIBN) was used to control the conjugation length of poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)‐co‐(1,4‐phenylene vinylene)] (MEH‐PPV) by free radical addition. In this way a series of MEH‐PPV with various conjugation lengths was obtained. RESULTS: Characterization of MEH‐PPV using ¹H NMR and Fourier transform infrared spectroscopy demonstrated that the cyano groups of AIBN hydrolyzed into carboxyls. The carboxyl free radicals attacked the conjugated double bonds of MEH‐PPV, resulting in a decrease of trans‐vinylenes and in an increase of cis‐vinylenes as well as tert‐methyls on the backbone. Changing the conjugated structure of the polymer caused the peaks of UV and fluorescence spectra to shift to the blue. CONCLUSION: The resulting MEH‐PPV derivatives can emit orange‐red, green and blue light. It is expected that they could be used to prepare PPV‐based materials that could modulate white light emission, by simply blending the PPV derivatives emitting different colors. Copyright © 2008 Society of Chemical Industry