查询词典 mean density

At equilibrium,the rate of the metal dissolution is equal to the rate of the cathodic reaction,and the rate of the reaction is directly proportional to the current density by Faradar's law ;therefore:（6）and the Nernst equation can be rewritten(7)where B is a constant and i0 is the exchange current density,which is defined as the anodiccurrent density at the standard electrode potential.

在平衡，金属溶解的率与负极反应的率是相等的，并且反应的率与电流密度直接地是比例由Faradar的法律；因此：(6)和能斯脱等式可以被重写(7) B是常数的地方，并且i0是交换电流密度，被定义作为正极电流密度在标准电极电位。

The main research work of this dissertation is as follows: Based on the chemical reaction engineering theory and the nitrobenzene electroreduction mechanism, the plate and frame electrolyzer was designed and applied to the process of electroreduction nitrobenzene to p-aminophenol. This dissertation measured the residence time distribution data of the electrolyzer by means of the pulse response method and studied the rule of flow pattern along with the current capacity change. Under different conditions ,this dissertation studied the cyclic voltammetry properties of nitrobenzene on different electrodes by means of the dynamic cyclic voltammetry method and the electrode materials applied to the NB electroreduction have been selected primarily.Baseed on the results of cyclic voltammetry tests, this dissertation used p-electrode systems to measure the steady-state- polarization curves of nitrobenzene on different electrodes in H-type diaphragm cell, and obtained each primary factor s influence rule and the exchange current density value of each electrode.And then on the basis of the conclusions of fundamental researchs upword, the effects of influence factors on the the yield of p-aminophenol and the current efficiency,such as electrode material, current density, quantity of electricity circulated, nitrobenzene concentration . sulpuric acid concentration and so on, have been studied in detail in the systems of hign temperature , strong acidity and oxygen-poorthrough a series of electrolysis experiments in this paper.After all using Pb as anode Monel metal as cathode Dupont Nafion 417 cation-exchange membrane as membrane, this dissertation obtained the optimum technological condition: reaction temperature about 85C, current density 500A m-2, sulphuric acid concentration 20%wt.

论文的主要研究工作为：运用化学反应工程理论，结合硝基苯的电还原机理，设计出用于硝基苯直接电还原合成对氨基苯酚实验的板框式电解槽，并利用脉冲响应法测定了该板框式电解槽的停留时间分布数据，研究了流型随流量变化的规律；通过动态循环伏安法研究了硝基苯在不同电极上、不同条件下的循环伏安特性，初步评选出了用于硝基苯电还原的电极材料；结合循环伏安的测定结果，在H型隔膜电解槽中采用三电极体系测定了硝基苯在不同电极上、不同条件下的稳态极化曲线，得到了各主要因素的影响规律及硝基苯在各个电极上电还原的交换电流密度数值；在基础研究结论指导下，采用板框式电解槽，在高温、强酸、贫氧系统中，进行了一系列的电解实验，分别考察了电极材料、电流密度、通电量、硝基苯浓度、硫酸浓度等因素对收率及电流效率的影响，最终选择以蒙乃尔合金电极作为阴极、铅合金为阳极、Dupont Nofion 417阳离子交换膜为隔膜，得到由硝基苯直接电还原制对氨基苯酚的最佳电解工艺条件：反应温度85℃，电流密度500A·m~(-2)，硫酸浓度20％wt。

HP were determined by rapid urease test,Warthin-Starry silver stain and polyme rase chain reaction,and expression of P21,P53,C-myc and C-erbB-2 were detecte d by immunohistochemicology (Streptaovidin/Peroxidase,SP) method,and were evalua ted with positive expressive integrality,the mean optical density an d the integral optical density in computer assisted image analysis system.

方法经内镜和病理诊断的胃癌91例，用快速尿素酶试验，改良W-S银染色和PCR方法检测上述标本中Hp；以S-P免疫组织化学法检测P21、P5 3、C-mcy及C-erbB-2，并用阳性表达积分半定量和免疫组化图像分析进行比较。

At first, we introduce in detail relativistic mean-field theory, where a common Lagrangian density is presented. Starting with this Lagrangian density, we can obtain the Dirac equation and Klein-Gordon equations for nucleon and meson field by using Euler-Lagrangian equation.

本文首先详细介绍了相对论平均场理论的一些公式推导，给出了常用的一般的相对论平均场的拉格朗日量，从这个拉氏量出发，利用Euler-Lagrange方程就可导出核子与介子场的运动方程。

The metrics include patch density, largest patch index, edge density, area-weighted shape index distribution, area- weighted fractal index distribution, mean Euclidean nearest neighbor distance dlstributlon,standard deviation of Euclidean nearest neighbor distance distribution, coefficients of variation of Euclidean nearest neighbor distance distribution, contagion, interspersion and juxtaposition index, cohesion, Shannon's diversity index and Simpson's diversity index.

根据生态区划计算描述中国陆地景观结构的13种景观结构指数，包括斑块密度、最大斑块指数、边界密度、面积加权斑块形状指数、面积加权斑块分维度、平均最近斑块距离、最近斑块距离的标准差、最近斑块距离的相异系数、蔓延度、分布邻接指数、结合度、香农多样性指数、辛普森多样性指数。

The most sensitive analysis parameter is the mean density and the highest frequency density.

晶体图像分析系统的分析指标以平均灰度和最高频率灰度最敏感。

By using image disposal and analysis system, the number density and mean light density were assessed.

应用数理统计软件SPSS 10.0for windows进行统计学分析。

In accordance with the mean bone mineral density lower than 25% of the standard model group has two parts to achieve an average bone mineral density in osteoporosis standards,show that the model is successful.

按照骨密度均数低于假手术组25%的标准，则模型组两个部位的平均骨密度已达到骨质疏松症的标准，表明造模是成功的。

A weak correlation existed between wood basic density and latitude/longitude, while a strong negative correlation existed between wood basic density and annual mean temperature, temperature in January, frostless season and accumulated temperature over 10℃ of the seed source.

种源木材基本密度虽与产地经纬度相关性较小，但却与产地年均温、1月均温、无霜期和≥10℃积温呈显著的负相关。

Sp were evaluated by computer-assisted image analysis software, and the content of OPG determined by immunohistochemistry, which included mean optical density 、positive area density in bone trabecula and total positive area of cancellous bone, were evaluated by computer-assisted image analysis and semiquantitative analysis.

Sp，免疫组化方法结合图像分析半定量分析OPG在胫骨的表达，测定平均光密度、OPG在骨小梁中阳性表达的面积密度和OPG在松质骨骨组织阳性表达的总面积。

The Master of Science degree program in Economics features a curriculum that is flexibl...

在经济学理学硕士学位的课程计划的特点是灵活而全面的方法，在理论和应用课程培训工作。

This module is used for constructing and visualizing 3D models.

该模块是用于建设和可视化的三维模型。