共查询到20条相似文献，搜索用时 22 毫秒
1.
The salt-gradient operation mode used in ion-exchange simulated moving bed chromatography (SMBC) can improve the efficiency of protein separations. A detailed model that takes into account any kind of adsorption/ion-exchange equilibrium, salt gradient, size exclusion, mass transfer resistance, and port periodic switching mechanism, was developed to simulate the complex dynamics. The model predictions were verified by the experimental data on upward and downward gradients for protein separations reported in the literature. All design and operating parameters (number, configuration, length and diameter of columns, particle size, switching period, flow rates of feed, raffinate, desorbent and extract, protein concentrations in feed, different salt concentrations in desorbent and feed) can be chosen correctly by numerical simulation. This model can facilitate the design, operation, optimization, control and scale-up of salt-gradient ion-exchange SMBC for protein separations. 相似文献
2.
手性药物对映体分离理论与应用技术在药物及生命科学研究领域中占有极为重要的位置,是当前制药工业和生物技术发展的尖端研究课题。模拟移动床色谱已被国际上公认为制备规模拆分手性药物的最有效手段。介绍了模拟移动床色谱数学模型和数值分析方法的最新进展。 相似文献
3.
A simulated moving bed （SMB）, equipped with eight silica-gel columns, was used to separate phosphatidylcholine （PC） from soybean phospholipids. The effects of flow rate in Sections 2 （Q2） and 3 （Q3）, switching time, feed flow rate and feed concentration on the operating performance parameters： purity, recovery, productivity and desorbent consumption were studied. Operating conditions leading to more than 90% purity in both outlet streams have been identified, together with those achieving optimal performance. Regions leading to complete separation are observed and explained theoretically. As the mass-transfer effect was not considered, the triangle theory only gives initial guesses for the optimal operating conditions. 相似文献
4.
邱志宏 《柳州职业技术学院学报》2008,8(1):55-58
本文首先介绍了应用于高速光纤通信中信号接收的几种电路结构,并对其进行分析与总结,提出了采用光电转换的等效电路模型。然后对光电接收转换电路进行改进,提出了一种前馈式的信号接收器总体设计方案,并对该方案的性能进行分析,重点是信息传输的速度和误码率,详细介绍了前馈式的信号放大原理与实现方法。 相似文献
5.
陶海英 《江西电力职业技术学院学报》2012,25(2):14-16,37
分析了500kV线路进行分闸操作出现分闸过电压的机理,建立了元件的仿真计算JMarti模型,该模型具有可靠的计算准确性和数值稳定性。结合实际算例,采用电磁暂态分析程序EMTP进行仿真研究。研究结果对于超高压系统的合理设计、实际系统的安全运行具有一定的实用价值。 相似文献
6.
An improved mathematical model for a circulating fluidized bed (CFB) boiler based on the model developed earlier by the authors was applied to simulate the operation of a 12 MW CFB boiler. The influences of the excess air ratio, primary air ratio, coal particle size distribution, coal properties (ash content and volatile content) and Ca/S ratio on the boiler operation were analyzed. The results showed that the model simulation may be applied to the optimum design and economic operation of the CFB boiler. 相似文献
7.
采用二维非稳态吸附模型,运用MATLAB语言对活性炭固定床吸附处理甲基紫废水过程进行模拟,得到了吸附中甲基紫流出相浓度随处理时间及床层高度的三维及二维分布图,所得模拟结果与文献中实验所得结果基本吻合.在此基础上,模拟活性炭吸附甲基紫废水过程中活性炭粒径、流动相流量与流出相浓度的关系,以进一步研究影响此吸附过程的因素,这将为反应器的设计和最优化操作提供一定的理论指导作用. 相似文献
8.
结实型谐振支路及其在软开关变换器中的应用 总被引：1，自引：0，他引：1
本文给出了结实型谐振支路实现软开关的工作原理和运行特性 ,详细讨论了结实型谐振支路拓扑在软开关直直变换器和软开关逆变器中的各种应用 .结实型谐振支路可构成升降压软开关直直变换器、具有输出功率自动限制特性的隔离型软开关直直变换器 ,可实现部分串联谐振直直变换器功率管的零电压、零电流开关 ,可用于移相控制全桥直直变换器实现滞后桥臂功率管的软开关 ,可构成结实型谐振极逆变器和结实型谐振直流环节逆变器 .本文对各变换器的工作原理、特性、实现软开关的条件进行了讨论 ,给出了实验和仿真波形 . 相似文献
9.
将参数化设计技术应用于齿轮轴的零件设计,通过设计参数来驱动齿轮与轴颈的尺寸,简化齿轮轴模型的设计与修改操作,并提高成组产品的设计效率。该系统基于Solid Edge软件,利用VB进行了二次开发研究,实现了齿轮轴的参数化设计,提高了齿轮轴的设计效率及质量。 相似文献
10.
王磊 《韩山师范学院学报》2013,(3):27-32
由于开关元件的存在,开关变换器的运行中蕴含着丰富的非线性现象,包括分岔、混沌等．以平均电流控制的Boost变换器为研究对象,在简化的离散时间模型基础上,运用非线性动力学对其稳定性问题进行了探讨,得出了在不同负载电阻下输入电压的稳定边界值．基于雅可比矩阵特征值的稳定性分析和仿真结果吻合得较好．文章的研究对平均电流控制的Boost变换器在环路设计、参数选择和稳定裕量估计有一定的实用价值． 相似文献
11.
李润 《兰州石化职业技术学院学报》2012,12(1):16-18
应用Pro/E参数化和行为建模技术,实现齿轮的优化设计,分析零件的质量如何随齿轮齿数的变化而变化。首先在Pro/Engineer的建模环境中完成齿轮零件的三维建模,在完成优化设计的数学模型定义之后,转换到Pro/Mechanica工作环境中,通过灵敏度分析找出关键的设计变量（齿轮的齿数）对优化目标进行优化,从而可以根据设计者的特定要求分析出最佳的设计结果。该方法可以推广应用于其他零件的结构设计中。 相似文献
12.
刘福生 《河北能源职业技术学院学报》2009,9(1):55-56
操作电源在变电站运行中占有非常重要的地位,若操作电源使用不合理或出现故障,继电保护可能拒动,引发上一级变电站开关动作,而使事故扩大,因此操作电源的可靠性必须引起重视。 相似文献
13.
分布式CAD环境中基于操作语义的实时协同设计 总被引：1，自引：0，他引：1
提出了一种应用于分布式CAD环境中的基于操作语义的协同设计模型. 主要目的是为了减少数据转换的耗时量以及降低对网络带宽的需求, 从而改善协作能力, 提高实时同步的效果. 首先回顾了实时协同设计的发展现状, 讨论了3种实时协同设计模型. 其次, 给出了操作语义的定义, 并提出了一个操作语义模型框架. 操作语义包含原始设计数据和实际操作过程, 表达CAD系统中的设计者意图和操作活动. 最后, 根据操作语义模型, 定义了CAD操作原语, 该原语可以从CAD操作中提取也可以映射成CAD操作命令; 给出了一种基于该模型的分布CAD协同体系结构, 并通过一个实例加以验证. 相似文献
14.
DMF萃取精馏法精制乙酸乙酯的过程模拟研究 总被引：1，自引：0，他引：1
本文利用化工流程模拟软件AspenPlus采用萃取精馏,以DMF为萃取剂,对乙酸乙酯生产中的产品精制进行了模拟计算,详细分析了理论板数、进料位置、溶剂比和回流比对产品浓度的影响。结果表明,最优工艺方案为：理论板数40,粗酯进料位置29,萃取剂进料位置6,溶剂比1.6,回流比2.0,塔顶产品乙酸乙酯含量达到99.9%,质量达到GB/T3728-2007优等品标准,为分离过程的优化操作和设计提供依据。 相似文献
15.
建立了模拟逆流降膜除湿过程传热传质的数学模型,给出了传热传质的控制方程和适当的边界条件和气液界面条件.采用氯化钙作为除湿剂,运用控制容积法对降膜除湿溶液与被处理空气之间的除湿过程进行了分析和计算.获得了相应的除湿溶液与被处理空气的速度场、温度分布和出口参数.计算结果表明:沿着除湿器高度方向溶液和空气的温度、溶液的浓度、空气的湿度在入口区域变化较快而在出口区域变化较慢.可分别通过增加竖壁的高度、溶液的入口浓度和溶液的流速来改善除湿过程;同样,也可通过降低空气的流速或空气入口湿度达到改善除湿过程的目的.研究结果有利于改进除湿器的性能,为太阳能液体除湿、空调系统的优化设计和运行调节提供了理论依据. 相似文献
16.
ZHAI Guo-fu CHEN Yang-hua REN Wan-bin 《浙江大学学报(A卷英文版)》2007,8(3):422-425
The performance in vibration environment of switching apparatus containing mechanical contact is an important element when judging the apparatus’s reliability. A piecewise linear two-degrees-of-freedom mathematical model considering contact loss was built in this work, and the vibration performance of the model under random external Gaussian white noise excitation was investigated by using Monte Carlo simulation in Matlab/Simulink. Simulation showed that the spectral content and statistical characters of the contact force coincided strongly with reality. The random vibration character of the contact system was solved using time (numerical) domain simulation in this paper. Conclusions reached here are of great importance for reliability design of switching apparatus. 相似文献
17.
B. S. Sekhon 《Resonance》2004,9(3):42-49
A gemini surfactant (GS) consists of two conventional surfactant molecules chemically bonded together by a spacer. The two
terminal hydrocarbon tails can be short or long; the two polar head groups can be cationic, anionic or nonionic; the spacer
can be short or long, flexible or rigid. The GS need not be symmetrically disposed about the center of the spacer. GS can
self-assemble at much lower concentrations and are superior in surface activity as compared to conventional surfactants. GS
are very attractive for catalysis and adsorption applications, new synthetic vectors for gene transfection, analytical separations,
solubilization processes, nanoscale technology, biotechnology, enhanced oil recovery and as paint additives. 相似文献
18.
Yuan Yuan Fei Li Yue-min Wang Rong-qing Zhang Li-ping Wei Hai-chang Wang 《Journal of Zhejiang University. Science. B》2009,10(5):391-394
To shorten operation time and improve survival rate of rats with myocardial ischemia or myocardial infarction, we use a novel device comprised of a face mask and a head/neck retainer in this study. We report the basic design of the novel respiratory face mask (RFM) and evaluate its performance in a rat model of myocardial ischemia. The device is cost-effective and easier to handle than other devices, such as tracheal intubation. Compared with conventional tracheal intubation, we found that RFM shortens operation time significantly while keeping blood indices normal; the mean operation time for rats in the mask group was (32±3) min, and that for the intubation group was (45±7) min (P<0.05). Moreover, the size and shape of the RFM can be changed according to the body weight of rats. In conclusion, RFM is an appropriate device for the establishment of myocardial infarction or ischemia-reperfusion in rats. 相似文献
19.
GUO Bao-feng Xiao Da-wei 《重庆大学学报(英文版)》2005,4(3):129-133
Using virtual reality for interactive design gives a designer an intuitive vision of a design and allows the designer to achieve a viable, optimal solution in a timely manner. The article discusses the process of making the Virtual Reality System of the Humble Administrator＇s Garden. Translating building data to the Virtual Reality Modeling Language （VRML） is by far unsatisfactory. This creates a challenge for computer designers to do optimization to meet requirements. Five different approaches to optimize models have been presented in this paper. The other methods are to optimize VRML and to reduce the file size. This is done by keeping polygon counts to a minimum and by applying such techniques as object culling and level-ofdetail switching. 相似文献
20.
王新华 《深圳信息职业技术学院学报》2007,5(1):35-38
建立了易拉罐尺寸设计的优化模型,得到了正圆柱形罐尺寸设计的最优解和上部为正圆台下部为正圆柱形罐以及CCB-1A型罐尺寸设计的次优解。作为例证,检验了椰树牌椰奶245ml罐尺寸设计的最优性和王老吉凉茶310ml罐及可口可乐汽水355ml罐尺寸设计的次优性,从而回答了2006年全国大学生数学建模竞赛C题所提出的问题。 相似文献