共查询到19条相似文献，搜索用时 127 毫秒
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由丁二酸酐和二乙基三胺为起始原料采用熔融缩聚法合成出了端氨基超支化聚酰胺；确定了适宜的合成路线和合成反应条件，用FTIR，1H-NMR和GPC对超支化聚酰胺进行了表征。 相似文献
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柱层析是一种使用非常广泛和有效的提纯手段.但在使用时要注意硅胶和洗脱剂的使用,还要结合装柱、上样和过柱的技巧,才能使柱层析在实验中发挥更好的作用. 相似文献
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本文介绍了一种实验室演示装置一BALL&PLATE装置，可运用传统的PID、PD控制方法和模糊控制方法对装置进行控制，并且对几种控制方法的优劣进行了比较，本文重点介绍了模糊控制方法在该装置中的运用，建立了模糊控制模型，确定了模糊控制规则和模糊控制判决方法，这种方法已经运用于BALL&PLATE装置中，效果良好，我们正准备推广这项实验装置。 相似文献
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程泓 《河北能源职业技术学院学报》2011,11(4):76-78
本文介绍了超导现象,超导的基本原理和超导的研究现状,同时介绍了一种确定超导温度的实验方法及所利用的实验装置。利用伏安法测量了YBaCuO超导体的超导温度,对实验结果进行了分析和讨论,最后提出了伏安法测量超导体转变温度时的注意事项。 相似文献
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工业冷库门运行速度的大小对于冷库门的使用性能具有很大的影响。本文针对冷库门运行过程中速度控制的方法进行研究,提出了通过采用变频控制技术实现对冷库门的速度进行控制。通过试装测试,结果表明采用基于变频控制技术的控制装置可以实现对冷库门速度的有效控制,冷库门可以快速的开、关,并减少对冷库门框的冲击。 相似文献
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《绵阳师范学院学报》2016,(8):23-27
以柠檬酸和聚丙烯酸作为模板剂,采用一氧化碳还原法,还原锌基复合气凝胶,制备出炭气凝胶,开发出了一种炭气凝胶制备的新技术;通过用场发射扫描电镜(FESEM)与氮气吸脱附测试对气凝胶的微观结构进行了表征,结果表明:以柠檬酸为模板剂时,气凝胶的微观结构较密实,多孔现象不明显,比表面积370 m2/g,孔径分布在410 nm;以聚丙烯酸为模板剂时,孔洞分布均匀,具有典型的三维网络结构,其比表面积为1 860 m2/g,孔径分布在610 nm;以聚丙烯酸为模板剂时,孔洞分布均匀,具有典型的三维网络结构,其比表面积为1 860 m2/g,孔径分布在660 nm. 相似文献
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利用硅胶柱层析和薄层层析分离甲基托布津合成产物中的微量杂质。柱层析分离杂质的适宜条件：0.5mL的粗品上硅胶（80-100目）的层析柱,流动相为乙酸乙酯∶石油醚（3∶2,V/V）,流速为0.9mL·min-1,并通过高效液相色谱及时测定结果,经过多次富集得到杂质纯品,并由液质联用仪和核磁共振分析杂质结构,得出杂质是因为反应过程中发生副反应（水解或者氧化）,所以应创造无氧的反应条件。 相似文献
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高平 《泰州职业技术学院学报》2011,11(2):61-62,34
目的建立分子排阻色谱法测定云芝糖肽的分子量分布的方法。方法用分子排阻色谱法,色谱柱：TSKgelG 4000SW（7.5mm×300m m）柱,流动相：0.02mol/L醋酸钠溶液,柱温：30℃,已知分子量右旋糖酐分子量标准品作校正标准,示差折光检测器。流速：0.50m l/min;进样量：10μL。结果根据建立的方法测定,分析了3批样品,得到云芝糖肽的排阻色谱图并计算出重均分子量大于40000的相对百分比为59.7%,63.6%,66.6%。结论该方法简便、快速,可用云芝糖肽的质量控制。 相似文献
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采用硅胶柱色谱法分离纺织油剂中的各组分,利用红外光谱法和质谱法对所分离组分进行结构鉴定,确定该样品的化学组成,并用重量法对其含量进行定量分析。 相似文献
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GONG Shunfeng LU Yong GAO Feng JIN Weiliang 《天津大学学报(英文版)》2006,12(B09):248-253
For a building structure subjected to impulsive loading, particularly shock and impact loading, the response of the critical columns is crucial to the behaviour of the entire system during and after the blast loading phase. Therefore, an appropriate evaluation of the column response and damage under short-duration impulsive loading is important in a comprehensive assessment of the performance of a building system. This paper reports a dynamic analysis approach for the response of RC columns subjected to impulsive loading. Considering that the dynamic response of a column in a frame structure can also be affected by the floor movement which relates to the global vibration of the frame system, a generic column-mass model is used, in which a concentrated mass is attached to the column top to simulate the effect of a global vibration. To take into account the high shear effect under impulsive load, the model is formulated using Timoshenko beam theory, and three main nonlinear mechanisms are considered. Two typical scenarios, one under a direct air blast loading, and another under a blast-induced ground excitation, are analyzed and the primary response features are highlighted. 相似文献
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For a building structure subjected to impulsive loading, particularly shock and impact loading , the response of the critical columns is crucial to the behaviour of the entire system during and after the blast loading phase. Therefore, an appropriate evaluation of the column response and damage under short-duration impulsive loading is important in a comprehensive assessment of the performance of a building system. This paper reports a dynamic analysis approach for the response of RC columns subjected to impulsive loading. Considering that the dynamic response of a column in a frame structure can also be affected by the floor movement which relates to the global vibration of the frame system, a generic column-mass model is used, in which a concentrated mass is attached to the column top to simulate the effect of a global vibration. To take into account the high shear effect under impulsive load, the model is formulated using Timoshenko beam theory, and three main nonlinear mechanisms are considered. Two typical scenarios, one under a direct air blast loading, and another under a blast-induced ground excitation, are analyzed and the primary response features are highlighted. 相似文献
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本文主要对锦带花乙酸乙酯提取物化学成分进行研究。采用醇提法提取锦带花中的化学成分,并依次用石油醚、乙酸乙酯、正丁醇萃取,通过柱色谱,薄层制备色谱,凝胶柱色谱及重结晶等方法对乙酸乙酯提取物进行分离纯化。得到5个化合物,分别鉴定为:槲皮素(quercetin,I),原儿茶酸(protocatechuic,II),莨菪亭(Scopoletin,III),6-甲氧基-7-氧代异戊烯基香豆素(6-methoxy-7-oxo isopentenyl coumarin,IV),β-谷甾醇(β-sitosterol,V),以上化合物均首次从该种植物得到。 相似文献
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A series of new amphiphilic poly[methyl(3,3,3-trifluoropropyl)siloxane]-b -poly(ethylene oxide)(PMTFPS-b-PEO)diblock copolymers with different ratios of hydrophobic segment to hydrophilic segment were prepared by coupling reactions of end-functional PMTFPS and PEO homopolymers.Copolymers were shown to be well defined and narrow molecular weight distribution(MWD)(1.07～1.3)by characterizations such as gel permeation chromatography(GPC)and 1H-nudear magnetic resonance(1H-NMR). 相似文献
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The affinity heptapeptide(HWWWPAS)for insulin,selected from phage display library,was coupled to EAH Sepharose 4B gel and packed to a 1-mL column.The column was used for the affinity purification of insulin from protein mixture and commercial insulin preparation.It was observed that the minor impurity in the commercial insulin was removed by the affinity chromatography.Nearly 40 mg of insulin could be purified with the 1-mL affinity column.The results revealed the high specificity and capacity of the affinity column for insulin purification.Moreover,based on the analysis of the amino acids in the peptide sequence,shorter peptides were designed and synthesized for insulin chromatography.As a result,HWWPS was found to be a good alternative to HWWWPAS,while the other two peptides with three or four amino acids showed weak affinity for insulin.The results indicated that the peptide sequence of HWWWPAS was quite conservative for specific binding of insulin. 相似文献
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To investigate the seismic behavior of specially shaped column joints with X-shaped reinforcement,two groups of specimens with or without X-shaped reinforcement in joint core region were tested under constant axial compression load and low reversed cyclic loading,which imitated low to moderate earthquake force.The seismic behavior of specially shaped column joints with X-shaped reinforcement in terms of bearing capacity,displacement,ductility,hysteretic curve,stiffness degradation and energy dissipation was studied and compared to that without Xshaped reinforcement in joint core region.With the damage estimation model,the accumulated damage was analyzed.The shearing capacity formula of specially shaped column joints reinforced by X-shaped reinforcement was proposed with a simple form.The test results show that X-shaped reinforcement is an effective measure for improving the seismic behavior of specially shaped column joints including deformation behavior,ductility and hysteretic characteristic.All specimens were damaged with gradual stiffness degeneration.In addition,X-shaped reinforcement in the joint core region is an effective way to lighten the degree of cumulated damage.The good seismic performance obtained from the specially shaped column joint with X-shaped reinforcement can be used in engineering applications.The test value is higher than the calculated value,which indicates that the formula is safe for the design of specially shaped column joints. 相似文献