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Search Results: 1 - 10 of 88148 matches for " 杜金健 "
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中压区域补偿型动态电压调节器设计
,,,刘开培
电力系统自动化 , 2015, DOI: 10.7500/AEPS20141215004
Abstract: 对适用于10kV配电网区域电压跌落治理的动态电压恢复器进行了设计,给出了基于级联H桥的主电路、取电装置、无变压器耦合电路的设计方法,并针对中性点不接地配网系统中电压跌落的特点,提出了一种仅需补偿电压跌落相电压即可恢复负载侧线电压的参考值计算方法。最后,基于PSCAD搭建了仿真模型,分析了不同故障类型下动态电压调节器(DVR)的补偿效果以及取电装置对系统的影响,通过实验验证了DVR硬件设计与参考电压计算方法的正确性和有效性。
菊苣根乙醇提取工艺优化及除草活性测定
刘玉燕,鸿,陈果,王佺珍,
草业科学 , 2011,
Abstract: ?利用L16(43×26)混合正交考察乙醇体积分数、料液比、浸泡时间、浸泡重复次数、超声温度、超声时间、超声输入功率和超声重复次数8个因素对菊苣(Cichoriumintybus)根提取率的影响;以稗草(Echinochloacrusgali)、反枝苋(Amaranthusretroflexus)为研究对象测定菊苣根提取物的除草活性。8个提取因素对提取率影响均显著(P<0.05),其优化组合为乙醇体积分数0、料液比1∶8、超声温度65℃、浸泡24h、浸泡2次、超声30min、超声输入功率400W和超声2次;因素重要性按递减顺序是乙醇体积分数,浸泡重复次数,超声输入功率,浸泡时间,超声重复次数,超声温度,料液比、超声时间。菊苣根粗提物的16种处理对稗草和反枝苋均有除草功能,且抑制作用显著(P<0.05);与2,4二氯基苯氧酸(1g/L)阳性对照组比较,部分处理组有等效功能(P>0.05)。L16(43×26)混合正交准确优化了8个因素且得出重要性次序,菊苣根粗提物有开发植物源除草剂的潜力。
特高压直流同塔混压输电线路反击耐雷性能计算方法研究
,志叶,阮江军,张亚飞,,陈媛
电瓷避雷器 , 2015, DOI: 10.16188/j.isa.1003-8337.2015.02.017
Abstract: 绝缘子串的绝缘闪络判据是线路耐雷水平计算中的关键因素,本文基于EMTP-ATP软件,提出了模拟绝缘子闪络过程的先导发展反击闪络模型,通过算例进行了分析验证,研究了3种闪络模型对特高压直流同塔混压输电线路反击耐雷水平的影响,比较了3种方法的特点。在以相交法作为绝缘闪络判据时,选取两种典型的800kV伏秒特性曲线进行耐雷水平计算,计算结果一致。通过对线路架设参数变化进行了仿真分析,并提出了相应的防雷建议。研究结果表明:500kV线路是特高压直流同塔混压双回线路的反击薄弱所在,需进行重点防护;与相交法相比,特高压直流同塔混压线路反击耐雷水平研究推荐采用先导发展法模拟绝缘子闪络。
多稀疏回声状态网络预测模型
Prediction model with multiple sparse echo state network

沈力华,陈吉红,曾志刚,宝瑞,
控制理论与应用 , 2018, DOI: 10.7641/CTA.2017.70315
Abstract: 针对单回声状态网络难以充分描述数据信息的问题, 提出多稀疏回声状态网络预测模型. 通过对相关回声 状态网络的组合权值及由相关样本得到的基函数的权值同时进行学习, 获得优化的多个稀疏回声状态网络组合模 型. 所提模型不同于双稀疏相关向量机等多核学习模型, 它不需要选择特定的核函数及相应的核参数. 因此, 该模 型不但能更好的描述数据信息, 避免了双稀疏相关向量机及其他多核学习中核函数及其参数不易选择的问题. 同 时, 所提模型不需要采用交叉验证的方式确定回声状态网络的谱半径和稀疏度, 只需确定相应的区间. 本文通过两 组标杆数据和一组实际数据仿真实验, 与传统回声状态网络方法相比, 验证了所提模型具有更好的预测性能.
Considering the problem that using a single echo state network (ESN) is difficult to describe the data information adequately, we propose a multiple sparse echo state network prediction model. The optimized combination model of echo state network is achieved by learning the sparse weights of the related ESN and the sparse weights of related basis functions determined by related sample simultaneously. And the proposed model is achieved with no need of determining the kernel functions and the related kernel parameters, which is different from the double sparse relevance vector machine and the other multiple kernel learning models. So the proposed model not only can describe the information of the datasets better but also can avoid the selection procedure of kernel functions and kernel parameters. There is no need of selecting the spectral radius and sparsity of ESN by cross validation in the proposed model and only the interval of spectral radius and sparsity are needed to be determined. The experimental results of two groups of benchmarking data and a group of real-world dataset demonstrate that the proposed model has better prediction performance.
五轴加工刀具轨迹NURBS插补技术的研究
Study on NURBS Interpolation Technology of Five-axis Machining Tool Path

蔡安江,,宋仁杰,李林
- , 2017,
Abstract: 为了解决直线插补和圆弧插补的不足,以三次NURBS参数样条为基础对五轴加工的NURBS插补的进行研究;基于UG前置输出刀位数据点,分别对刀尖点和刀轴矢量参数化,反算求出控制顶点,实现NURBS插补,同时通过对插补点的曲率计算,推导出插补误差与进给速度的关系,进而用进给速度控制插补误差;基于IMSpost和HEIDENHAIN iTNC530数控系统,进行NURBS插补功能的后置处理器的研究,实现高效NC程序的输出;基于MATLAB,以叶轮的NURBS插补刀具轨迹进行仿真验证,实现了NURBS刀具轨迹的NC输出。
In order to solve the problem of linear and circular interpolation, the relevant principles of five-axis machining of NURBS interpolation computation was studied by using cubic spline Non-Uniform Rational B-Splines parameterization; tip point and tool axis vector parameterization were made based on the UG pre-output cutter location data points so as to calculate its control points by using inverse calculation achieved NURBS interpolation. Then It can insert with feed rate control interpolation error through the calculation of the interpolation points of the curvature derived relationship interpolation error and feed rate. By using CNC system of HEIDENHAIN iTNC530 and IMSpost, the postprocessor of NURBS interpolation function was conducted so as to achieve the output NC program. The impeller' NURBS interpolation was conducted via MATLAB so as to achieve processing requirements
五轴数控加工3D刀具补偿及其后置处理方法
Method on five-axis CNC machine 3D cutter compensation and post-process

蔡安江,宋仁杰,,,
- , 2018,
Abstract: 为解决五轴数控加工过程中,由于刀轴矢量不断变化,刀具补偿方向无法确定引起刀具在三维空间中无法补偿的问题,提出一种基于前置与后置处理的五轴数控加工3D刀具补偿方法。针对具备3D刀具补偿功能的数控系统,推导出五轴数控加工3D刀具补偿的补偿矢量与补偿后刀位点坐标的矢量计算方程,并基于前置三维软件(UG)的前置处理,建立了控制刀位文件格式的函数,实现了UG前置处理在五轴数控加工模块下输出包含切触点在内的刀位文件。根据SIEMENS 840D数控系统实现3D刀具补偿的数字控制(NC)指令格式要求,以非正交摆头转台五轴数控机床为例,通过逆向运动学变换提出具体的后置处理方法。基于智能制造软件IMSpost(后处理程序编辑器)平台和所提出的后置处理方法开发了专用后置处理器,自动获取了具有3D刀具补偿矢量信息的NC程序,基于仿真软件VERICUT平台对不同工况下整体叶轮仿真加工的结果进行对比。结果表明:当刀具因磨损发生尺寸变化时,采用提出的方法和开发的具有3D刀具补偿功能的后置处理器所获取的NC程序,可以将加工表面的欠切误差控制在0.1 mm以下,且无过切现象,有效地提高了五轴数控加工的精度和效率,避免了刀具磨损后发生刀具尺寸改变必须返回计算机辅助制造(CAM)系统重新生成刀位文件,以及再次进行后置处理的繁琐过程,验证了所提出的前置处理与后置处理方法的正确性和有效性。
In five-axis machining, as the tool axis vector changes, the tool compensation direction can not be determined resulting in the problem that the tool can not be compensated in the three-dimensional space. In order to solve this problem, a 3D tool compensation method for five-axis CNC machining was proposed based on pre-processing and post-processing. For numerical control systems with the 3D tool compensation function, the vector calculation equation about compensation vector and cutter location point coordinates after compensation in five-axis 3D tool compensation was derived. By creating the function which controls the cutter location file format in UG pre-processing, achieved that in the five-axis CNC machining module, the UG pre-processing could output the cutter location file including the contact point coordinates. According to the NC instruction format that SIEMENS 840D CNC system requests to achieve 3D cutter compensation function, a five-axis CNC machine tool with non-orthogonal table/spindle-tilting type was used as an example, and the specific post-processing method based on the inverse kinematic transformations was proposed. Based on IMSpost platform and post-processing method, a dedicated post-processor was developed. Then the NC code with 3D cutter compensation vector information could be auto-obtained. By using the VERICUT software, simulation results of integral impeller in different operating conditions were compared. The results show that when the tool size changes due to wear, adopting the proposed pre-processing method and the NC code obtained by the developed post-processor with 3D cutter compensation, the undercutting error can be controlled less than 0.1 mm without over-cutting phenomenon. It effectively improves the accuracy and efficiency of five-axis CNC machining, and avoids the complicated process that the programmer must return to CAM system to generate new tool paths and post-process cutter location data again because of tool size change due
血蓝蛋白分子结构与生物学功能
Research Progress on Molecular Structure and Biological Functions of Hemocyanin
 [PDF]

震环,
Bioprocess (BP) , 2015, DOI: 10.12677/BP.2015.53005
Abstract: 血蓝蛋白是三大类呼吸功能都之一,目前仅发现存在于节肢动物门和软体动物门等少数动物类中。本文系统介绍了节肢动物门和软体动物门血蓝蛋白的分子结构特征,并基于血蓝蛋白的独特结构,详细阐述了动物体内迄今发现的有关血蓝蛋白的主要生物学功能特点,同时对当前针对血蓝蛋白研究过程中常用的技术与方法进行了介绍。通过以上内容,有助于深入认识血蓝蛋白这种独特的呼吸功能蛋白的研究现状,也有助于拓展对血蓝蛋白开发利用前景的认识。
Hemocyanin is one of three main types of respiratory proteins and currently only occurs in minority animal groups including arthropoda and molluscan species, respectively. Here we summarized the distribution and structural characteristics of hemocyanin superfamily members existing in the arthropoda and molluscan species, and the major biological features ever found were also introduced in detail. Commonly used techniques and methods during the investigation and re-search for the hemocyanin were listed and explained here. The above helps to understand the re-search status of hemocyanin and expand the practical application of it.
内壁填充环状金属泡沫的管内流动凝结换热
徐会,屈治国,艳平,何雅玲,陶文铨,卢天
化工学报 , 2011,
Abstract: 通过采用在圆管内壁填充环状金属泡沫的方法强化管内对流凝结换热,实验研究了制冷剂R134a在内壁填充环状金属泡沫管内的流动凝结的压降和换热,克服了完全填充金属泡沫管流动阻力大的缺点。用于计算传热系数的管壁温度通过热电偶测量得到。综合分析了质量流速和两相流体干度对流动凝结压降及传热系数的影响。研究结果表明内壁填充环状金属泡沫管压降远大于光管,压降随质量流速和干度的增加而迅速增大且呈非线性。通过壁面温度分布和温度波动对内壁填充环状金属泡沫管内的两相流型进行判别,发现影响该类强化管凝结换热的两种主要流型:分层流和环状流。内壁填充环状金属泡沫管的凝结传热系数大于光管,且随着质量流速和干度的增加传热系数增大,该类强化管流动凝结传热系数是光管的2倍左右。
西昆仑大红柳滩岩体地质和地球化学特征及对岩石成因的制约
乔耿彪,张汉德,伍跃中,谋顺,,赵晓,陈登辉
地质学报 , 2015,
Abstract: 新疆西昆仑康西瓦断裂带南缘的巴颜喀拉褶断带中分布着中生代三十里营房―泉水沟岩浆岩带,该带中最典型的岩体即为大红柳滩岩体,其主要岩性为中细粒二长花岗岩。结合锆石阴极发光图像(CL)和U、Th元素特征,通过SHRIMP锆石U-Pb定年,获得大红柳滩二长花岗岩体的年龄为220±2.2Ma~217.4±2.2Ma,时代属晚三叠世(T3)。二长花岗岩含石榴子石和电气石,具有高硅(SiO2为71.77%~74.20%)、富碱(Na2O+K2O为6.18%~8.02%)、富钾(K2O为3.03%~5.30%)、铝饱和指数较高(A/CNK介于1.20~1.59)的典型特点,属高钾钙碱性过铝质系列。岩石相对富集轻稀土且轻重稀土元素分馏明显(LREE/HREE为10.21~11.82,(La/Yb)N为24.06~31.65),具有强烈的铕负异常(δEu为0.25~0.44);明显富集Ta、Hf等高场强元素及Rb、Th、U等大离子亲石元素,而贫Ba、Sr、Ti、Nb、Zr等元素,显示经历了较高程度的分异演化(分异指数DI平均89.40%),综合矿物组合和地球化学特征的判别表明,大红柳滩岩体属于高分异的S型花岗岩,是同碰撞背景下壳源物质部分熔融的产物。根据岩体的成因类型并结合区域构造环境演化,分析认为晚三叠世随着古特提斯洋向北消减直至最终闭合,构造应力由俯冲作用转化为碰撞挤压作用环境时形成了大红柳滩岩体,表明该区在晚三叠世已进入陆-陆碰撞造山的构造演化阶段。
绵羊Myostatin基因敲除载体的构建
孙丹,,立新,魏彩虹,张莉,路国彬,,吕延飞
生物技术通报 , 2011,
Abstract: 根据Myostatin基因突变可导致肌肉量激增而产生"双肌"表型的特点,构建绵羊Myostatin基因置换型敲除载体。利用LA-PCR技术成功地扩增得到绵羊Myostatin基因同源臂序列,其中同源长臂4.9kb,包括全部的exon1,intron1,exon2及部分启动子和大部分intron2;同源短臂1.1kb,包括部分exon3和3′非翻译区序列,将二者连入PloxpII正负筛选敲除骨架载体,利用骨架载体上Neo基因替代Myostatin基因的exon3,从而成功构建专门针对Myostatin第3外显子区域缺失的置换型敲除载体PloxpⅡ-OVIS-MSTN。酶切和测序鉴定证明载体构建正确,为后续获得绵羊Myostatin基因缺失型体细胞株奠定试验基础。
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