24 resultados para Valve


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A comprehensive two-dimensional liquid chromatographic separation system based on the combination of a CN column and an ODS column is developed for the separation of components in a traditional Chinese medicine (TCM) Rhizoma chuanxiong. Two columns are coupled by a two-position, eight-port valve equipped with two storage loops and controlled by a computer. The effluent is detected by both the diode array detector and atmospheric pressure chemical ionization (APCI) mass spectrometer. More than 52 components in the methanol extract of R. chuanxiong were resolved and 11 of them were preliminary identified according to their UV and mass spectra. (C) 2004 Elsevier B.V. All rights reserved.

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趋磁细菌(Magnetotactic bacteria)的研究是国际微生物学研究热点之一。趋磁细菌体内含有纳米单磁畴的氧化铁/硫化铁(Fe3O4或Fe3S4)晶体,称为磁小体。由于趋磁细菌营养条件要求苛刻,在环境中需要微好氧条件,且营养类型属于化能自养,使得培养趋磁细菌时常遇到问题。 本研究首先通过正交试验优化趋磁细菌AMB-1菌株培养条件,在培养条件铁源为奎尼酸铁0.02 mmol/L,装瓶量75% ,pH值6.7,温度25 ℃时,AMB-1 OD600达到0.440(1.166×109 cells/ml)。同时运用磁收集传代法,使带有磁小体的AMB-1细胞比例占95%以上(Cmag值稳定在1.9-2.0)。 在AMB-1具有较好的生物量,同时又具有较好的含磁小体细胞比例后,研究磁小体的变化过程。通过透射电镜观察磁小体变化过程,发现培养24 h细菌体内已有较小晶体形成(平均27 nm,n=188)且沿长轴分布;48 h晶体长大(平均43 nm,n=203)且形成分段链沿长轴排列;72 h晶体进一步成熟(平均50 nm,n=191)仍以分段链沿长轴排列;随后细菌逐渐衰亡磁小体变小,168 h可见部分自溶细菌中仍有磁小体链(平均37 nm,n=186);192 h细菌自溶磁小体链(平均33 nm,n=184)分散到环境中。 通过透射电镜在细胞水平上研究趋磁细菌细胞分裂时发现,磁小体在细菌分裂时采用两种分离方式:一种为磁小体分配到两个子细胞;另一种为磁小体只分配到一个子细胞。无磁小体的子细胞,在随后的生长过程又分为两种情况:一种为细胞逐渐产生磁小体,另一种为不再产生磁小体。这种现象的发现,解释了随着传代次数的增多,细菌磁性有所下降的原因(Cmag值降低)。 在对趋磁细菌磁小体合成机制的研究中,常使用基因敲除的办法获得缺陷型,并与野生型对比进行研究。但是,利用基因敲除获得缺陷型不仅操作繁琐并且所得缺陷型不稳定。本研究利用特殊的磁富集传代法,先将带有磁小体的菌体收集并连续传代,筛选获得了高磁菌株;利用这种方法,收集不含磁小体的菌体并连续传代,筛选获得了无磁菌株。 趋磁细菌磁小体在医疗、环保等领域具有广阔应用价值,但是目前由于趋磁细菌难以大规模培养,并且磁小体纯化存在成本高等原因,将磁小体真正实际应用尚有一段距离。通过研究磁小体在趋磁细菌中的变化过程发现,AMB-1菌株在培养192 h后自溶,并且磁小体随着细胞的破碎释放到环境中去。

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阀门泄漏的在线监测一直是困扰流程工业的难题,采用传统有线监控方式需要巨大的布线安装成本。本文通过结合无线通信技术和超声检测技术,研究并开发了一种基于无线通信的阀门泄漏检测系统,可极大地降低测控系统的投资和使用成本,通过实时检测阀门的工作状态,及时发现并定位泄漏位置,实现工业生产的节能降耗。

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以模拟人对混水阀的调节过程为基础,提出一种新的仿人控制算法.该控制算法模拟人在控制时的粗调和微调,并使控制量逐步逼近最终稳定控制量的过程.算法中的参数具有明确的物理意义,可根据不同的控制指标方便地调节,并且能够获得足够的稳态误差.采用本文控制算法,不需要有精确的被控对象模型,即使在有较大干扰的情况下,仍可以获得较好的控制性能.

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本文提出了一种新型气液缸和气液位置伺服系统。该系统采用气液连动控制,充分发挥液压与气动各自的优点,大大提高了位置控制精度,同时克服单纯气动的特点。在气液回路上,利用两位三通阀、“PCM”阀组及油开关阈实现分区控制和准确定位,解决了快速性和定位精度之间的矛盾,通过分析和实验研究表明,此方案是可行的。

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本文所介绍的水下机械手液压控制系统为一典型的具有变回油压力封闭式系统。文中阐述了此种系统液压动力机构的设计原理及静、动态参数的分析计算方法。对于在变回油压力下,由四通阀控制的非对称油缸的静态特性进行了详细的分析。给出了在不同回油压力下,不同面积比的非对称油缸、阀的负载压降及最大空载流量的变化规律。这对于确定水下机械手的液压动力机构的参数提供了依据。

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根据数字液压驱动单元的运行原理,分析了在空载与加载情况下该数字驱动单元的内部液体流动状态,并以这一流动状态原理为依据,改进设计了传统的液控单向阀。数字液压驱动单元样机及试验结果表明:该数字液压驱动单元与应用传统液控单向阀体的驱动单元相比,具有更加紧凑的体积、更高的响应速度及运行可靠性和显著的节能效果。

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Now low porosity and low permeability reservoir is one of the main targets of exploration for the onshore oilfields of China. Most of the reservoirs are none flowing because of bad formation percolation condition, poor gas oil ratio , low formation pressure coefficient and other factors. In the recent years, a number of domestic oilfields have carried out some research work and achieved some success on oil testing and production technology in such formation. But by now, there is still no systematic and mature technology, particularly testing technology in none flowing formation is still needed further study. Based on study the key problem of well testing and interpretation technology in none flowing formation, solve the important problems in well testing technology, continuously improve and innovate geological information acquisition technology for none flowing reservoir, accurately acquire boundary information and evaluate reservoir flow characteristics. Its wide application remarkable result has shown. The main results and cognitions obtained from research are as follows: 1. This new technology research results help solve the occurrent problems in well testing process for none flowing formations, such as small investigation radius, poor representative of interpretation results from the poor data, low level application of interpretation results. This new technology helps create favorable conditions for early precise reservoir evaluation and reduction of the risk of exploration. 2. The technological difficulties for none flowing well testing are successfully solved by using none flowing formation combined mechanical tool string .This method has been proved by its applications to be able to improve the efficiency of the testing and the quantity of the acquired test data ,and so as to enhance the application of the interpretation results of the test in development of oil fields. 3. The application of the rotary formation tester, selective test valve, well testing string and their allier tools help to resolve problems such as the operation of opening and shutting-in the well under different well conditions, to broaden the scope of well test technology for none flowing formations. 4. Refined Testing Technique for production Wells has greatly shortened the testing dwration and improved the efficiency and accuracy of operation, enriched test results, and at the same time created conditions for conducting multi-well interference well testing.

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This study employed the compliance, identification, and internalization model of attitude change to explore the mechanism of rule-following behaviors in organizations. The objectives of this study were to examine the effects of individual utilitarianism and formalism on rule compliance, deference and rule-breaking behaviors, and the relationships between legitimacy, organizational identification, and value internalization. I surveyed 262 employees from a high-tech corporation in Beijing. After Confirmative Factor Analysis, Regression Analysis, and Structural Equation Modeling, I summarized main conclusions as follow. First, rule legitimacy and organizational identification have different effects on different rule behaviors. Perceived rule legitimacy and organizational identification have direct positive effect on rule deference. But the effects of legitimacy on rule-compliance and rule-breaking are moderated by organizational identification and value internalization. Only under high identification or value congruence with organization, could legitimacy perception predict rule compliance and breaking. Second, individual formalism (IF) has positive effect on rule compliance. IF’s positive effect on rule deference only appear under high value congruence between individuals and organization. Third, organizational identification works as a “valve” in the relationship between individual viewpoints and rule-breaking. Organizational identification turns off the tendency of utilitarianism to break rules, and turns on the tendency of formalism to inhibit rule-breaking. Forth, attitudinal and behavioral facets of utilitarianism and formalism have different influences on rule-following behaviors. Only individuals who are both attitudinal and behavioral formalists show deference to rules, while formalism as behavioral tendency predicts less rule-breaking. Fifth, innovation behaviors coexist independently with compliance and deference to rules. But the division between innovation and rule-breaking is obscure. Organizational identification facilitate both rule following and innovation. Sixth, women comply with rules more than men do, while men break more rules than women do. More aged people develop deeper identification with their organizations, and higher deference to rules. Individuals with higher education are fewer formalists, and accordingly defer to rules less and break more.