帮忙翻译论文摘要

宝臭臭滴妈妈 2018-11-25 12:54:46 360 浏览

换热器是化工、炼油、动力、食品、轻工等许多工业部门广泛应用的一种通用设备。其性能的好坏直接影响过程工业热经济性的高低。近年来，由于能源危机，强化传热技术和新型换热器的研究... 换热器是化工、炼油、动力、食品、轻工等许多工业部门广泛应用的一种通用设备。其性能的好坏直接影响过程工业热经济性的高低。近年来，由于能源危机，强化传热技术和新型换热器的研究得了飞速发展。本次的实验是在前人设计的带螺旋折流片（下简称螺旋片）换热器的基础上再在内圆管多加上扰流柱，分析不同操作参数和结构参数条件下流体传热情况，由此得出影响换热器传热性能的条件，为进一步研究静态混合器传热情况和其在实际工程及设计中的应用奠定基础。本文对换热器进行了研究，测得壳程空气进出口温度，利用温差传热，以努塞尔准数作为衡量换热器传热性能的标准，分别考察了雷诺数对努塞尔准数的影响，并与空管进行了比较。换热器器中由于扰流柱的作用，使进入管中的流体在流经扰流柱时产生旋涡，有效地消除了径向主流道的速度梯度和温度梯度。因传热边界层大大减薄，使得边界层内流体不断得到更新，热阻下降，传热过程得到强化。通过实验可以得出一些结论: 由于有螺旋片同扰流柱的存在使得扰动螺旋型换热器的传热效果明显要优于圆滑管型换热器同螺旋型换热器;螺旋片使流体具有向外甩开的离心力，流体在流过扰流柱时因被分流、切割、再生，不仅加速了流速并且在柱后形成涡流，加速壁面流体的更新，减薄粘性边界层底层的厚度，从而提高了传热性能; 同一模型在不同Re下，随着Re的增加，Nu也随着增加，在不计阻力时，模型的传热效果随着Re的增加而提高不要翻译软件翻译的。如果好再加分展开

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帮忙翻译论文摘要: 换热器是化工、炼油、动力、食品、轻工等许多工业部门广泛应用的一种通用设备。其性能的好坏直接影响过程工业热经济性的高低。近年来，由于能源危机，强化传热技术和新型换热器的研究... 换热器是化工、炼油、动力、食品、轻工等许多工业部门广泛应用的一种通用设备。其性能的好坏直接影响过程工业热经济性的高低。近年来，由于能源危机，强化传热技术和新型换热器的研究得了飞速发展。本次的实验是在前人设计的带螺旋折流片（下简称螺旋片）换热器的基础上再在内圆管多加上扰流柱，分析不同操作参数和结构参数条件下流体传热情况，由此得出影响换热器传热性能的条件，为进一步研究静态混合器传热情况和其在实际工程及设计中的应用奠定基础。本文对换热器进行了研究，测得壳程空气进出口温度，利用温差传热，以努塞尔准数作为衡量换热器传热性能的标准，分别考察了雷诺数对努塞尔准数的影响，并与空管进行了比较。换热器器中由于扰流柱的作用，使进入管中的流体在流经扰流柱时产生旋涡，有效地消除了径向主流道的速度梯度和温度梯度。因传热边界层大大减薄，使得边界层内流体不断得到更新，热阻下降，传热过程得到强化。通过实验可以得出一些结论: 由于有螺旋片同扰流柱的存在使得扰动螺旋型换热器的传热效果明显要优于圆滑管型换热器同螺旋型换热器;螺旋片使流体具有向外甩开的离心力，流体在流过扰流柱时因被分流、切割、再生，不仅加速了流速并且在柱后形成涡流，加速壁面流体的更新，减薄粘性边界层底层的厚度，从而提高了传热性能; 同一模型在不同Re下，随着Re的增加，Nu也随着增加，在不计阻力时，模型的传热效果随着Re的增加而提高不要翻译软件翻译的。如果好再加分展开

帮忙翻译论文摘要: 换热器是化工、炼油、动力、食品、轻工等许多工业部门广泛应用的一种通用设备。其性能的好坏直接影响过程工业热经济性的高低。近年来，由于能源危机，强化传热技术和新型换热器的研究... 换热器是化工、炼油、动力、食品、轻工等许多工业部门广泛应用的一种通用设备。其性能的好坏直接影响过程工业热经济性的高低。近年来，由于能源危机，强化传热技术和新型换热器的研究得了飞速发展。本次的实验是在前人设计的带螺旋折流片（下简称螺旋片）换热器的基础上再在内圆管多加上扰流柱，分析不同操作参数和结构参数条件下流体传热情况，由此得出影响换热器传热性能的条件，为进一步研究静态混合器传热情况和其在实际工程及设计中的应用奠定基础。本文对换热器进行了研究，测得壳程空气进出口温度，利用温差传热，以努塞尔准数作为衡量换热器传热性能的标准，分别考察了雷诺数对努塞尔准数的影响，并与空管进行了比较。换热器器中由于扰流柱的作用，使进入管中的流体在流经扰流柱时产生旋涡，有效地消除了径向主流道的速度梯度和温度梯度。因传热边界层大大减薄，使得边界层内流体不断得到更新，热阻下降，传热过程得到强化。通过实验可以得出一些结论: 由于有螺旋片同扰流柱的存在使得扰动螺旋型换热器的传热效果明显要优于圆滑管型换热器同螺旋型换热器;螺旋片使流体具有向外甩开的离心力，流体在流过扰流柱时因被分流、切割、再生，不仅加速了流速并且在柱后形成涡流，加速壁面流体的更新，减薄粘性边界层底层的厚度，从而提高了传热性能; 同一模型在不同Re下，随着Re的增加，Nu也随着增加，在不计阻力时，模型的传热效果随着Re的增加而提高不要在线翻译的。希望帮一忙！如果好再加100分，我现在非常急，马上就要交了。展开

摘要，关键字翻译: 摘要：从天然食用紫卷心菜中以水作溶剂提取紫红色素，分别用微波和超声波作辅助并对提取温度、时间及次数等工艺条件进了研究。实验结果表明，微波辅助之以水作溶剂提取天然食用紫卷心... 摘要：从天然食用紫卷心菜中以水作溶剂提取紫红色素，分别用微波和超声波作辅助并对提取温度、时间及次数等工艺条件进了研究。实验结果表明，微波辅助之以水作溶剂提取天然食用紫卷心菜中紫红色素效果Z好，Z佳提取条件为：微波火力为80，辐射时间180秒。关键字：紫卷心菜；红色素；提取；微波；超声波。展开

翻译纳米材料摘要（2）: Moreover， the particle size of incorporated ZnO calculated from the effective mass model was close to the results obtained from HRTEM. The synthesis method developed in course of this work can be used for the fabrication of different polym... Moreover， the particle size of incorporated ZnO calculated from the effective mass model was close to the results obtained from HRTEM. The synthesis method developed in course of this work can be used for the fabrication of different polymer-inorganic transparent nanocomposites with other functionalities. In the second part of the thesis， we studied a method for the fabrication of micro-porous surface layer – made of copper nanoparticles – on the surface of copper plates (suitable for heat exchangers). The micro-porous surfaces were formed from dendritic network of copper nanoparticles obtained by electrodeposition from solution using dynamic bubble formation and removal as template. The surface layer engineered and its structures were optimized in order to enhance the boiling heat transfer coefficient. To further optimize the dendritic structure， additional annealing step was introduce and its effect on the surface layer structure and properties were investigated. The properties of the deposited surface structures were investigated and its effect on the enhancement of the heart transfer coefficient has been studied. The fabricated enhanced surface has shown an excellent performance in nucleate boiling. Pool boiling tests were performed on refrigerant fluids (R134a) to evaluate the boiling performance of the electrodeposited nanostructured micro-porous structures. At heat flux of 1 W/cm2， the heat transfer coefficient is enhanced over 15 times compared to a plain reference surface. A model has been presented to explain the enhancement based on the structure characteristics. 展开

【生物专业英语】摘要翻译: Abstract:Heavymetals，suchascadmium，copper，lead，chromiumandmercury，areimportantenvironmentalpollutants，particularlyinareaswithhighanthropogenicpressure.Theirpresenceinthea... Abstract: Heavy metals， such as cadmium， copper， lead， chromium and mercury， are important environmental pollutants， particularly in areas with high anthropogenic pressure. Their presence in the atmosphere， soil and water， even in traces can cause serious problems to all organisms， and heavy metal bioaccumulation in the food chain especially can be highly dangerous to human health. Heavy metals enter the human body mainly through two routes namely: inhalation and ingestion， ingestion being the main route of exposure to these elements in human population. Heavy metals intake by human populations through food chain has been reported in many countries. Soil threshold for heavy metal toxicity is an important factor affecting soil environmental capacity of heavy metal and determines heavy metal cumulative loading limits. For soil-plant system， heavy metal toxicity threshold is the highest permissible content in the soil (total or bioavailable concentration) that does not pose any phytotoxic effects or heavy metals in the edible parts of the crops does not exceed food hygiene standards. Factors affecting the thresholds of dietary toxicity of heavy metal in soil-crop system include: soil type which includes soil pH， organic matter content， clay mineral and other soil chemical and biochemical properties; and crop species or cultivars regulated by genetic basis for heavy metal transport and accumulation in plants. In addition， the interactions of soil-plant root-microbes play important roles in regulating heavy metal movement from soil to the edible parts of crops. Agronomic practices such as fertilizer and water managements as well as crop rotation system can affect bioavailability and crop accumulation of heavy metals， thus influencing the thresholds for assessing dietary toxicity of heavy metals in the food chain. This paper reviews the phytotoxic effects and bioaccumulation of heavy metals in vegetables and food crops and assesses soil heavy metal thresholds for potential dietary toxicity. 用翻译软件的免回，哥也有，真诚求助高手！展开

论文摘要在线翻译急急急！！！: 论文摘要如下：由于自动化程度的提高，各个生产环节都集中控制或检测，测量仪器与被测对象的距离较远，环境条件较为复杂。特别是被测信号是微弱的而且是深埋在噪声中的，怎样对微弱信号进行检测越来越受到人们的重视。微弱信号检测是一门新兴的技术学科... 论文摘要如下：由于自动化程度的提高，各个生产环节都集中控制或检测，测量仪器与被测对象的距离较远，环境条件较为复杂。特别是被测信号是微弱的而且是深埋在噪声中的，怎样对微弱信号进行检测越来越受到人们的重视。微弱信号检测是一门新兴的技术学科，应用范围遍及光、电、磁、声、热、生物、力学、地质、环保、医学、激光、材料等领域。其仪器已成为现代科学研究中不可缺少的设备。微弱信号检测的目的是从噪声中提取有用信号，或用一些新技术和新方法来提高检测系统输出信号的信躁比。本文提出采用MAX038函数发生器产生同步的正交信号源，采用双差分减法器实现阻抗到电压的变换，并利用双相锁定放大器实现电导幅值及相位检测，实现电泳芯片电容耦合非接触电导时频域分析。电容耦合非接触电导检测（C4D）是近几年出现的一种新型电导检测技术，它彻底解决了接触电导检测存在的检测电极易污染、受被测系统高场强电压干扰等问题，已经成功的应用于毛细管电泳检测上，具有广泛的应用潜力。在微弱信号检测中，噪声是一种不希望的扰乱信号，锁定放大器所具有的强大抗噪声能力使得这个问题能够得到很好的解决。为减小噪声对有用信号的影响，常采用窄带滤波器滤除带外噪声，以提高信噪比，锁定放大器是一种采用互相关原理设计的同步相关检测仪器，它能检测输入信噪比达10的微弱信号。用Multisim2001进行仿真，该软件具有系统高度集成、界面直观、仿真功能完备、使用灵活方便等优点。展开

接地工程论文英文摘要: 我想找一篇范文

纳米材料的摘要翻译（7）: Drivers and Directions In the United States， the EPA and NIOSH are spearheading research into nanoparticles and their associated health risks through a variety of funded research projects and information exchange programs. NIOSH’s Web si... Drivers and Directions In the United States， the EPA and NIOSH are spearheading research into nanoparticles and their associated health risks through a variety of funded research projects and information exchange programs. NIOSH’s Web site also cites its participation in the multiagency National Nanotechnology Initiative and the Nanoscale Science， Engineering and Technology Subcommittee of the National Science and Technology Council’s Committee on Technology. But on the whole， the study of nanotechnology in the workplace is still in its infancy. Or as Keith Rickabaugh， technical director of materials and analytical services for RJ Lee Group， Monroeville， Pa.， puts it， “what has been learned is that there is much more to learn.” Rickabaugh goes on to say that， “We need to learn how to economically/reasonably establish safe work practices and engineering controls to protect workers from an ‘unknown’ exposure risk. That includes performing studies to document the health risks of nanosized particles， and training workers to understand and be able to characterize those materials.” 展开

急帮我翻译下这个摘要有写好的帮忙修改下: 摘要：实验测定和比较了九顶山鸡不同品系鸡肉中微量元素的含量的差异。以及同种品系胸肌和腿肌中微量元素的差异。分析不同品系和同种品系之间微量元素的差异。根据生长性能、鸡的血缘... 摘要：实验测定和比较了九顶山鸡不同品系鸡肉中微量元素的含量的差异。以及同种品系胸肌和腿肌中微量元素的差异。分析不同品系和同种品系之间微量元素的差异。根据生长性能、鸡的血缘、生产性能等把九顶山鸡分为九顶山鸡Ⅰ号，九顶山鸡Ⅱ号，九顶山鸡Ⅲ号。以九顶山鸡腿部肌和胸肌为实验材料采用微波消解及等离子发射光谱仪（ICP）测定其cd、co微量元素的含量，并进行对比。其结果表明 Abstract: This study is to compare trace elements Jiudingshan chicken (Gus Gallus) and the differences between other species. in same strains Breast and leg muscles difference between the trace element. According to the growth performance， chicken's blood， production performance， etc. Species can be divided into types I and ll and lll Jiudingshan chicken (Gus Gallus). Experimental material as the legs and chest， using microwave plasma atomic emission spectrometry (ICP) of the trace elements measured and compared. The results showed that: 展开

帮忙翻译: AttachingtheSampleChuckYouwillneeda#2Phillipsscrewdriverforthisstep.FollowingthedetailsshowninFig.2-4，installthesamplechuckbyfirstaligningthepinsonthebottomofthesamplechu... Attaching the Sample Chuck You will need a #2 Phillips screwdriver for this step. Following the details shown in Fig. 2-4， install the sample chuck by first aligning the pins on the bottom of the sample chuck with the receptacles on the alpha- SE base. Then tighten the upper two captive thumb screws. Next， use the Phillips screwdriver to tighten the lower two captive screws. Don’t over tighten the screws! It will make it difficult to remove them in the future; just ensure that the screws are snug. Finally， connect the vacuum line from the sample chuck to the vacuum fitting on the alpha-SE base. Releasing the Z-stage Shipping Lock To access the Z-stage shipping lock， first loosen the captive screw on the lamp/shipping lock access door， then open the access door by rotating 180°， as shown in Fig. 2-5. To release the Z-stage shipping lock， stand in front of the ellipsometer and use your left hand to balance the weight of the Z-stage (you will feel it lift up slightly). It will be difficult to release the shipping lock if you apply too much or not enough upward force. Next， use your right hand to move the shipping lock to the operating position (to the right， see Fig. 2-6). If the lock is hard to move， you can use a tool to gain more leverage. The shipping lock will move about 1/3” [8mm] to the right. Checking the Lamp Check that the QTH lamp in fully seated in the lamp housing. The lamp is located behind the actuator screw (see Fig. 2-6) and has two white wires protruding from the back of the lamp. Simply push down on the lamp ensuring that the lamp is fully seated in the lamp housing. Rotate the lamp/shipping lock access door to the closed position and hand tighten the captive screw. 拒绝翻译软件，翻译软件我自己也会用不是用翻译软件我就看不懂，只是，上来找人翻译就是希望翻译出比较容易看懂，不需要自己对照就可以看的说明书，如果用翻译软件，根本就词不达意，还是要自己对着原文件核实既然用了那么多积分，就希望有相当的成果，如果用翻译软件混积分，那就是人品问题了还有，某些人不要不懂乱说混积分展开

翻译一段纳米材料的摘要(1): Abstract Nanomaterials and nanotechnology have been hot issues during the recent decades. This thesis deals with the fabrication and engineering of novel nanomaterials with enhanced functionality， particularly nanocomposites and nanostruc... Abstract Nanomaterials and nanotechnology have been hot issues during the recent decades. This thesis deals with the fabrication and engineering of novel nanomaterials with enhanced functionality， particularly nanocomposites and nanostructured surfaces. The study includes two parts; in the first part， bulk transparent polymer-inorganic nanocomposites were produced by a novel synthesis method and its UV-absorption has been investigated. In the second part， nanostructured microporous surface layers， of copper， were fabricated by electrodeposition process and its effect on material’s performance for pool boiling has been investigated evaluated.In the first part of the thesis， bulk polymer-inorganic nanocomposites composed of poly(methylmethacrylate) (PMMA) and zinc compounds were prepared by an in situ sol-gel transition polymerization of zinc complex in PMMA matrix. The immiscibility of heterophases of solid organic and inorganic constituents was resolved by the in situ sol-gel transition polymerization of ZnO nanofillers within PMMA in the presence of dual functional agent， monoethanolamine， which provided strong secondary interfacial interactions for both complexing and crosslinking of constituents. Comprehensive characterization of the polymer-inorganic hybrid materials has been undertaken using a wide range of techniques; XRD， 1H NMR， FT-IR， TGA， DSC， UV-Vis， ED， SEM， TEM and HRTEM. The homogeneous PMMA-ZnO nanocomposites exhibited enhanced UV-sheltering effects in the entire UV range even at very low ZnO content of 0.02 wt%. 展开

帮忙找一下论文: 帮忙找一下关于红外技术发展史的论文或者资料急~~~~~~~~~~ 如果好~~我可以再加分

帮忙翻译2: 3.6. Advantages of chromia as promoter in copper-based Catalysts It should also be noted from Figs. 5 and 6 that in the steam reforming reaction to produce hydrogen for fuel cell applications， trace quantities (<0.4 wt.%) of Cr2O3 on Cu... 3.6. Advantages of chromia as promoter in copper-based Catalysts It should also be noted from Figs. 5 and 6 that in the steam reforming reaction to produce hydrogen for fuel cell applications， trace quantities (<0.4 wt.%) of Cr2O3 on Cu not only doubled the activity for the MSR but also halved the amount of CO formed， thereby enhancing H2 production. This improved selectivity reduces the problem of H2 separation from the reaction products in fuel cell applications. An important finding in this research is the role that very small amounts of Cr2O3 play in all the reactions investigated， namely， methanol synthesis， water gas shift and methanol steam reforming. In commercial co-precipitatedcopper-based methanol synthesis catalysts， copper is known to be the active component [3]. More recently， it has becomeestablished that ZnO promotes methanol synthesis and that surface species formed by Cu-ZnO interaction are responsible for methanol synthesis [42]. The role of Cr2O3 in commercial catalysts is thought to be similar to that of Al2O3， which is to act as stabilizer of the structure of the copper catalyst， thereby reducing sintering. In this study， as in a previous one [18] using a different technique todeposit chromia on the surface of skeletal copper， we have shown that Cr2O3 has a significant role in copper-based methanol synthesis from CO2. That role is to improve the methanol yield by reducing the RWGS reaction (Fig. 3) aswas observed in the earlier study [18]. A major finding of this study has been the very strong evidence the Cr2O3 has a synergistic effect on the activity of copper for methanol synthesis， methanol steam reforming and the water gas shift reactions. From Figs. 4 and 5 it can be seen that 0.85 wt.% Cr2O3 enhances the specific activity (mol/hm2 Cu) of skeletal copper 270% for the WGS and 150% for methanol steam reforming. In the case of methanol synthesis (Fig. 2) 0.61 wt.% Cr2O3 increases the specific activity of copper by 67%. The results for the WGS and MS reactions are similar to those obtained under the same reaction conditions using skeletal copper promoted by Cr2O3 which was deposited from sodium chromate in the caustic leach liquor [28]. In that study， the effect of chromia was more pronounced， with an increase in activity of 950% for theWGSand 168% for the MSR reaction， respectively， using skeletal copper containing 0.75 wt.% Cr2O3. For methanol synthesis over Cr2O3 promoted skeletal copperprepared using sodium chromate in the leach liquor， Ma et al. [18] observed no increase in the specific activity of copper. 展开

帮忙翻译一句话: Catalysts were prepared by pore volume impregnation of ç-alumina

数控机床维修技术的摘要是什么，？写论文······: 数控机床维修技术的摘要是什么，？我在写论文，哪位仁兄指点一二～～～～～！！谢谢了

求有关猪伪狂犬病的摘要翻译: 摘要：伪狂犬病（Aujeszky’s disease）是由伪狂犬病病毒（Pseudorabies virus，PRV）引起的家畜和多种野生动物共患的一种传染病。该病在西方一些先进的养猪业发达的国家已经得到控制或根除，但在我国仍肆意横行，已经严重影响了我国养猪业的发展。我国每年都... 摘要：伪狂犬病（Aujeszky’s disease）是由伪狂犬病病毒（Pseudorabies virus，PRV）引起的家畜和多种野生动物共患的一种传染病。该病在西方一些先进的养猪业发达的国家已经得到控制或根除，但在我国仍肆意横行，已经严重影响了我国养猪业的发展。我国每年都会由于猪伪狂犬病的爆发而受到巨大的经济损失。本文对PRV病毒的特点进行了阐述，并通过对国外净化该病的部分措施进行分析，简要提出了国内猪场应该如何控制和净化该病。翻译成英语就行~别用GOOGLE和WORD里的翻译，不好用。谢谢了~ 展开

帮忙检索会议论文: 哪位好心人能帮忙查一下“Does “Sell in May” effect exist in Chinese A share market?—— An empirical analysis based on ARMA-GARCH model”这篇会议论文有没有被CPCI-SSH数据库检索？跪谢！

高手帮忙翻译！！+100: 虚拟仪器是一种新的测试与测控技术，近年来得到了迅速发展，基于虚拟仪器的机器视觉系统就是其领域的一个重要分支。本文围绕基于虚拟仪器的机器视觉有关理论和其在玻璃瓶口缺陷检测中... 虚拟仪器是一种新的测试与测控技术，近年来得到了迅速发展，基于虚拟仪器的机器视觉系统就是其领域的一个重要分支。本文围绕基于虚拟仪器的机器视觉有关理论和其在玻璃瓶口缺陷检测中的具体应用进行了研究。针对玻璃瓶这一对象检测的高精度、高准确度、实时性的特点，本文提出了一种基于LabVIEW的数字图像处理检测方案，并在设计过程中解决了一系列关键问题：利用硬件和软件的编程实现了对玻璃瓶口的缺陷监测；使用阈值进行图像的二值化处理，并进行开启、闭合以增强图像质量；使用Vision Builder AI对有故障的图像进行故障特征识别；通过理论研究与实验，证明了本文所提出的玻璃瓶口缺陷监测方法是有效和可行的，为其机器视觉检测的进一步研究和开发奠定了很好的基础请用专业术语，不要用在线翻译。谢谢····好可以多加分展开

帮忙翻译一下，谢谢: IFRS13willhelpincreasetransparencywhenentitiesusemodelstomeasurefairvalue，particularlywhenusersneedmoreinformationaboutmeasurementuncertainty，suchaswhenthemarketforanasse... IFRS 13 will help increase transparency when entities use models to measure fair value， particularly when users need more information about measurement uncertainty， such as when the market for an asset or a liability has become less active. IFRS 13 requires entities to disclose information about the valuation techniques and inputs used to measure fair value， as well as information about the uncertainty inherent in fair value measurements (which was of particular concern during the global fi nancial crisis). Some of those disclosures， including the fair value hierarchy， were already introduced in March 2009 through an amendment to IFRS 7 Financial Instruments: Disclosures. Those disclosures have been relocated to IFRS 13. The requirements in IFRS 13 also incorporate the guidance in a FASB Staff Position (FSP) issued in April 2009. 展开

帮忙翻译一段英语: Plant material and culture conditions have been described (7). Briefly， a diploid tissue culture line， WOO1C， of wild carrot， Daucus carota L.， was maintained in Murashige and Skoog medium supplemented with 0.1 mg of 2，4-dichlorophenoxy... Plant material and culture conditions have been described (7). Briefly， a diploid tissue culture line， WOO1C， of wild carrot， Daucus carota L.， was maintained in Murashige and Skoog medium supplemented with 0.1 mg of 2，4-dichlorophenoxyacetic acid (2，4-D). To regenerate plants from the culture， callus tissue was transferred to the same medium devoid of 2，4-D (embryogenic medium). All experiments were performed with cultures grown in liquid medium. For convenience， cultures grown in 2，4-D-containing medium are referred to as "callus cultures"， and those grown in medium without 2，4-D as "embryo cultures." The growth of callus cultures was measured by the sidearmturbidity method (7). The number of cells at any time point of growth was estimated from turbidity in a Klett-Summerson calorimeter and was expressed in arbitrary units. For example， Klett 100 corresponds to ="2 X 106 cells per ml. The relationship is linear up to Klett 150 in our Klett-Summerson colorimeter. Suspension cultures ofWOOLC cell line are normally maintained at cell densities between 106 and 107 cells per ml in 0.1 mg of 2，4-D per liter (high-density culture) in shake flasks. During a quantitative study on embryogenesis， we found that maximal embryo production can be achieved by first incubating the culture at high density in medium without 2，4-D for one generation time and then diluting it to 2-3 x 104 cells per ml (low-density culture). To compare cultures of comparable density， callus cultures and embryo cultures were subjected to the same procedure. To initiate low-density embryo or callus cultures， an 8-day-old high-density culture grown at the logarithmic phase was washed three times with fresh callus or embryogenic medium and resuspended at 8 x 105 cells per ml for one generation (3 days) in its corresponding medium. It was then diluted to 2 x 104 cells per ml; 20 ml of the culture was incubated in a plastic Petri dish (9 cm in diameter) at 240C. The morphogenetic events of the cultures were examined and photographed under a dissecting microscope. 请不要用google的那个，我看不懂~~ 展开

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