查询词典 average 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。

Normal distribution in statistics is based on the probability density function in the form of representation, and set up a continuous random variable X, the probability density function f has the form of Figure 1, where a, b are constants and were known as the average value and standard deviation,π, e, respectively pi and natural constants, claimed that X subject to parameters a, b of the normal distribution.

正态分布在统计学中是以概率密度函数的形式表述的，设连续型随机变量X的概率密度函数f有图1中的形式，其中a、b为常数，分别被称为平均值和标准差，π、e 分别为圆周率和自然常数，则称X服从参数为a，b的正态分布。

The average electron density in the linear attenuation zone is about 10^-5 of neutral particle density, and can diffuse over a wide rarea, The conclusion will supply some valuable references to the research of electromagnetic wave and artificial plasma interaction, the plasma invisibleness research of missile and special aerocraft,and the design of artificial plasma source.

平缓衰减区中的平均电子密度约为中性分子密度的十万分之一。并且可以覆盖较大范围。这些结果对于电磁波与人工等离子体相互作用的研究、导弹和空间飞行器的等离子体隐身研究及人工等离子体发生器的设计有一定的参考价值。

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。

The average molar volume and theoretical density were estimated using the Monte-Carlo method based on 0.001 ebohr^(-3) density space.

用Monte-Carlo方法和自编程序，基于0.001 ebohr^(-3)等电子密度面所包围的体积空间求得分子平均摩尔体积和理论密度。

The characteristic parameters of tree belt, such as tree belt width, density, average canopy density, height, and distance from the source to the tree belts were included in the formula.

为了克服林带声衰减量计算过于简化而引起的公路交通噪声预测精度降低的不足，基于植物内部结构及吸声、散射机理的分析，建立了高速公路林带声衰减量计算公式，公式中包含了林带宽度、密度、平均灌幅、高度和林带近路侧距公路中心线距离等特征参数。

The AMF spore average density was 24.88 per 20 g soil , the species richness was 1.94 per soil sample, the species diversity index was 2.56, and the species evenness was 0.65. Glomus, but they all were of prominent genus in the investigation area and Acaulospora, Scutellospora were of common genus while Entrophospora was rarely found. In the 13 species AM fungi, G.mosseae was of prominent species, and G.geosporum, G.intraradices, G.etunicatum were of common speices, while the others were of rarely species. There were 87.5% sand fixation plant were infected with arbuscular mycorrhizal fungi, the highest spore density, the strongest infection strength of the whole roots and the best species richness belonged to Chenopodiaceae while Polygonacea was the lowest.

四属AM真菌中，Glomus为优势属， Scutellospora 、Acaulospora为常见属，Entrophospora则为稀有属；十三种AM真菌中，G.mosseae、G.geosporum分别为优势种、最常见种，G.intraradices，G.etunicatum为常见种，其余均为稀有种；五科固沙植物中，87.5%的植物能被菌根侵染，其中藜科植物孢子密度最高，整个根系侵染强度最强，种的丰度最高，蓼科植物孢子密度、整个根系侵染强度、种的丰度则最低；禾本科植物不仅具有最好的丛枝结构，且具有相对高的亲和性，能与12种AM真菌共生。

In ACC, NGF,TrkA and p75 mainly existed in cells of duct-like, cribriform and mass-like structures.According to the optical density scanning of immunohistochemistric stain of NGF and TrkA in salivary gland and tumor tissues and quantification analysis, it was shown that the average optical density of NGF and TrkA increased in order of salivary gland tissues around neoplasm, mucoepidermiod carcinoma, and adenoid cystic carcinoma.

2叫 吉林大学硕士学位论文通过对NGF和TrkA在涎腺组织和涎腺肿瘤中的免疫组织化学染色结果进行光密度扫描，对所测平均光密度定量分析，结果显示：NGF和TrkA平均光密度值按照肿瘤周围涎腺组织、豁液表皮样癌和腺样囊性癌依次升高，统计学分析在各组间均有极显著差异(P.01)，表明NGF和TrkA通过自分泌机制调控涎腺腺样囊性癌和豁液表皮样癌的生长与增殖，通过旁分泌机制参与涎腺腺样囊性癌向神经周围的浸润。

Results There were 9 kinds of rodents at Yanshan Mountain, including Rattus confucianus, Apodemus peninsulae, Apodemus agrarius, Mus musculus, Clethrionomys rufocanus, Rattus norvegicus, and Cricetulus triton, Soriculus hypsibius, Crocidura gmelini. The rodent density ranged from 3.13% to 7.33%, and average density was 5.83%.

结果 北京市东北部燕山山脉共捕获社鼠、大林姬鼠、黑线姬鼠、小家鼠、棕背、褐家鼠、大仓鼠、川西长尾鼩、北小麝鼩9种；不同生境地区小兽密度为3.13%~7.33%，平均5.83%；平均带病毒率为2.83%，抗体阳性率为3.77%。

When this condition occurs, inbound replication with the source partner is stopped on the destination domain controller and event ID 2042 is logged in the Directory Services event log.

计算机密码学是研究计算机信息加密、解密及其变换的科学，是数学和计算机的交义学科，也是一门新兴的学科。

Instructions: click on the thumbnails to see a larger image, then use the left-right arrow keys to scroll through the slideshow.

使用说明：滑鼠点在小图上即可放大观赏。开启后键盘左右键可用来换照片。