热处理对La_(0.9)Nd_(0.1)(NiCoMnAl)_5电极性能的影响

研究了热处理对Ｌａ０．９Ｎｄ０．１（ＮｉＣｏＭｎＡｌ）５电极材料结构、成分、脱氢压力－组成等温曲线（ＰＣＴ）、循环寿命的影响。Ｘ射线衍射结果表明热处理降低了评价主相峰的半高宽（ＦＷＨＭ）平均值，即降低了晶格应力。采用ＪＳＭ－８４０能谱分析仪对热处理前后合金成分进行分析，发现热处理使得合金中的Ｌａ、Ｍｎ向晶内扩散，而Ｎｉ、Ｃｏ、Ａｌ却向晶界偏聚。测定了室温下热处理前后的合金脱氢ＰＣＴ曲线及其电极循环寿命曲线，结果表明热处理使电极放电容量有所降低，同时却又使电极循环寿命有所提高，并且还降低了合金平衡压。     

一种新的动态二值化算法

本文提出了一种新的动态二值化算法，以实现从灰度点阵图象中提取其对象。通过分析象素和其所在的局部区和灰度值等数字特征，可以判断局部区的内是否存在对象，阈值和判断条件对应。     

Retinal optic disc localization using convergence tracking of blood vessels

Optic disc localization is of great diagnostic value related to retinal diseases, such as glaucoma and diabetic retinopathy. However, the detection process is quite challenging because positions of optic discs vary from image to image, and moreover, pathological changes, like hard exudates or neovascularization, may alter optic disc appearance. In this paper, we propose a robust approach to accurately detect the optic disc region and locate the optic disc center in color retinal images. The proposed technique employs a kernelized least-squares classifier to decide the area that contains optic disc. Then connected-component labeling and lumination information are used together to find the convergence of blood vessels, which is thought to be optic disc center. The proposed method has been evaluated over two datasets: the Digital Retinal Images for Vessel Extraction (DRIVE), and the Non-fluorescein Images for Vessel Extraction (NIVE) datasets. Experimental results have shown that our method outperforms existing methods, achieving a competitive accuracy (97.52 %) and efficiency (1.1577s).     

基于CCD的多级时效工艺对6061铝合金性能的影响

采用中心组合设计(Central composite design, CCD)试验方法对选定温度下的6061铝合金固溶+双级时效处理工艺中的时间参数进行系统试验设计,结合力学性能测试结果得出时间参数与抗拉强度的可靠数学模型(r²=0.9078)。通过模型计算及方差分析结果可知二级时效时间对抗拉强度的影响十分显著且与抗拉强度呈负相关关系。据此得出最佳热处理工艺为550 ℃×108 min固溶+180 ℃×246 min峰时效+220 ℃×3 min二级时效,该工艺下6061铝合金的抗拉强度值为345 MPa,断后伸长率为13.5%。     

五剑杆织机引纬机构创新设计及优化

为解决现有矿山机械输送带易失效损坏,其骨架织物织造效率低、纬纱张力不均及高速时剑杆振动易脱针等缺陷,研发了五剑杆织机.对五剑杆织机中引纬机构进行研究,设计了新型五剑杆引纬工艺,基于五剑杆引纬工艺设计了引纬机构和5层纬纱张力均匀装置,并利用ANSYS Workbench软件对关键部件剑杆的刚度及强度进行有限元分析,基于响应面法,以剑杆的最大变形为优化目标,对剑杆结构参数进行优化设计,最后在Adams软件中进行运动学仿真得到其运动曲线.结果表明:剑杆内径d1和外径D2对最大变形和最大应力敏感度最高.优化方案相较原方案最大变形减小了22.8％,最大应力减小了21.9％,仿真结果表明剑杆在中后期振动较大、振动幅值在允许范围之内.该设计与所得结果可为多剑杆织机的研发提供借鉴与参考.     

In situ synthesis of zinc oxide/selenium composite for UV blocker application

Development of reliable ultraviolet (UV) blockers is crucial for UV radiation protection applications such as sunscreen and UV-resistant fabric. To date, zinc oxide (ZnO) has been extensively used as a physical UV blocker worldwide but has also been criticized for with its unfavored UV-induced reactive oxygen species (ROS) generation phenomena. As an attempt to suppress the photocatalytic activity of ZnO without compromising its UV absorbance property, amorphous selenium (Se) nanoparticles (NPs) were incorporated to ZnO using a facile and cost-effective coprecipitation method. Additionally, this process also enables an economical synthesis route for harvesting amorphous Se NPs from an aqueous medium. The ZnO–Se composites were thoroughly characterized to confirm its enhanced UV absorptivity combined with high transparency in the visible light range and to understand the interaction between ZnO and Se. Besides, Se-induced photocatalytic activity suppression of ZnO was demonstrated using methylene orange as an indicator. In vitro study revealed that ZnO–Se composite had improved biocompatibility over ZnO but comparable bacteriostasis ability under full-spectrum light irradiation. These results suggest that ZnO–Se composite is a promising UV blocker with advantages of facile synthesis, UV-induced ROS generation diminishment and biocompatibility.     

0CrMnTiH齿轮钢的淬透性计算及窄淬透性带控制

采用非线性方程计算法计算20CrMnTiH钢末端淬透性,只需利用生产实际数据加以修正,就能进行精确的淬透性计算和预报,与实测值偏差不超过2HRC。采用化学成分设计和控制,保证20CrMnTiH钢△[C]不超过0.007%,△[Si]波动不超过0.04%,△[Mn]、△[Cr]不超过0.02%,△[Ti]不超过0.01%,△[Alt]不超过0.010%,[Ni]、[Cu]不超过0.05%,[Mo]、[W]、[V]不超过0.03%,[P]、[S]不超过0.020%,[N]和[B]分别不超过0.006 0%和0.0005%,并控制碳偏析指数不超过1.035%,可实现国际先进水平的末端淬透性HRC4带宽控制。     

一种基于分布式并行模型的海量机载LiDAR点云数据快速滤波方法

机载LiDAR点云数据是遥感大数据的重要组成部分,基于单机的处理算法已经无法满足海量点云数据处理的要求.首先,针对现有单机多级移动曲面拟合滤波算法存在粗差和拟合曲面精度不高的问题,提出适合海量机载LiDAR点云数据滤波的多级多窗口移动曲面拟合滤波算法(WHMCFA);其次,设计并实现基于MapReduce的PWHMCF...     

体型参数对旋流排沙渠道水沙特性的影响

为明确关键体型参数对渠道和排沙洞内水沙特性的影响,在模型试验研究的基础上开展了旋流排沙渠道的水沙两相流数值模拟。结果表明:起旋室高度对截沙率影响较为显著,最大相差5.41%;排沙洞直径、倾角和起旋室出口宽度对分流比影响显著,最大相差8.13%,增大倾角后改善了原排沙洞封闭端因壁面条件影响而产生的泥沙淤积;起旋室出口宽度对渠道内水沙特性基本无影响;不同体型下旋流排沙渠道均可高效、持续排沙,截沙率均大于90%,经过起旋室后,高含沙水流从排沙洞流出,下游渠道含沙量急剧减小。