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21.
本文根据使用新技术──双回路注(放)水系统在63上10工作面综采放顶煤开采覆岩破坏的探测结果,结合其它采矿方法的实测结果,应用断裂力学理论,研究了放顶煤开采覆岩移动变形破坏特征,为矿井安全生产提供了依据。 相似文献
22.
张晨 《科技情报开发与经济》2005,15(23):149-150
以太原市某工程为例,从实际的基坑设计中得出,基坑支护中土压力设计值一般都比实际值偏大;支护桩周围的土压力的主动区、被动区并不是一成不变的。提出用位移分析的土压力模型来区分实际工程中的主、被动区,而后进行土体受力定量的分析。 相似文献
23.
布里渊区内能带E(k)=E(-k)的对称性 总被引:1,自引:0,他引:1
说明了布里渊区内能带E(k)=E(-k)的对称性是时间反演对称性的结果,而与晶体的空间对称性无关.并且证明了当晶体具有中心反演对称性时,布里渊区内能带是二重简并的. 相似文献
24.
Chiral separations by host-guest complexation with cyclodextrin and crown ether in capillary zone electrophoresis 总被引:2,自引:0,他引:2
Summary Capillary zone electrophoresis using cyclodextrins and a chiral crown ether as buffer constituents was studied for the enantiomeric separation of drugs and amino acids. Based on results obtained from separation of racemic -amino acids both chiral selectors are compared with respect to resolution, efficiency and retention time. For (±)-Quinagolide effects of buffer composition and temperature are examined using -cyclodextrin as chiral agent. Optimum conditions were pH 2.5 at 30 mmol L–1 -cyclodextrin. A linear dependence of retention on -cyclodextrin concentration allowed calculation of formation constants of the host-guest complexes. Buffer concentration and temperature also influence resolution. The application of a chiral crown ether to the separation of optical isomers in capillary zone electrophoresis is described for the first time. Chiral recognition of solutes depends on the formation of protonated alkyl amines and separation is attributed to the formation of diastereomeric host-guest complexes with different interactions for each enantiomer. The effects of crown ether concentration on resolution are presented. 相似文献
25.
高效毛细管电泳的电导检测和紫外光度检测研究 总被引:3,自引:1,他引:3
本文自制商效毛细管电泳装置.研究了毛细管区带电泳电导检测和毛细管胶束电动色谱紫外光度检测。在电导检测中,制作铂丝微电导池,并由用电池隔膜制作的导电接口连接电泳毛细管和电导池,高压被有效隔离,实现柱后电导检测,用内径200μm、长70cm(到接口)石英毛细管在10kV电压下分离检测Li~-、Na~-、K~-。在电动色谱中将高效液相色谱仪与高压电源组成电泳装置,用内径100μm,长50cm(到检测器)石英毛细管和SDS胶束溶液在14kV电压下分离检测电中性化合物。 相似文献
26.
毛细管电泳法快速分离和检测肠毒性大肠杆菌 总被引:4,自引:0,他引:4
建立了快速分离和检测引起仔猪腹泻的肠毒性大肠杆菌K88、K99和 987P细菌细胞的毛细管区带电泳方法 ,并进行了腹泻仔猪粪便中肠毒性大肠杆菌的应用检测分析。结果表明 ,在电泳缓冲液为 0 0 5mol/LNa2 CO3 NaHCO3(pH 9 9)、分离电压为 1 4 1kV、检测波长为 2 1 0nm的电泳条件下 ,E coliK88、K99和 987P的细胞分别具有单一、稳定的特征谱峰 ,其保留时间的相对标准偏差RSD≤ 0 9% ;在确定的实验条件下 ,实现了腹泻仔猪粪便中肠毒性大肠杆菌的快速检测分析 ,发现将出生 5d~ 6d的腹泻仔猪粪便引入培养基中增殖后主要检出K88。 相似文献
27.
A new method to improve the analysis of phytochelatins and their precursors (cysteine, gamma-Glu-Cys, and glutathione) derivatized with monobromobimane (mBrB) in complex biological samples by capillary zone electrophoresis is described. The effects of the background electrolyte pH, concentration, and different organic additives (acetonitrile, methanol, and trifluoroethanol) on the separation were studied to achieve optimum resolution and number of theoretical plates of the analyzed compounds in the electropherograms. Optimum separation of the thiol peptides was obtained with 150 mM phosphate buffer at pH 1.60. Separation efficiency was improved when 2.5% v/v methanol was added to the background electrolyte. The electrophoretic conditions were 13 kV and capillary dimensions with 30 cm length from the inlet to the detector (38 cm total length) and 50 microm inner diameter. The injection was by pressure at 50 mbar for 17 s. Under these conditions, the separation between desglycyl-peptides and phytochelatins was also achieved. We also describe the optimum conditions for the derivatization of biological samples with mBrB to increase electrophoretic sensitivity and number of theoretical plates. The improved method was shown to be simple, reproducible, selective, and accurate in measuring thiol peptides in complex biological samples, the detection limit being 2.5 microM glutathione at a wavelength of 390 nm. 相似文献
28.
Huwei Liu Shize Qi Yingnan Zhang Aijin Huang Yiliang Sun 《Journal of separation science》1997,20(4):242-244
A capillary zone clectrophoresis method was developed for the determination of IMP and GIMP, commonly used as flavor enhancers in poultry feed, in a real sample of complex composition. A baseline separation of inosine 5′-monophosphate and guanosine 5′-monophosphate was achieved within 10 min and the other components in the sample did not interfere with the separation. Quantitative results obtained from pig feed samples are presented. The separation conditions and experimental reproducibility are also discussed. 相似文献
29.
30.
The actual mobilities and dissociation constants of acidic and basic pharmaceuticals were determined in methanol. Actual mobilities were derived from the dependence of the effective mobilities of the analytes on the pH of the methanolic background electrolyte solution (pH(MeOH)). The pKa values of the pharmaceuticals in methanol (pK(a,MeOH)) were calculated by non-linear curve fitting to the measured mobility values. It was found that the shift in pKa value (when compounds were transferred from water to methanol) increased with the acidity of the analyte. The average pKa shift for compounds exhibiting acidic properties in water was ca. 5.5 units, and the shift for basic compounds about 2 units. As was shown for a mixture of beta-blockers, the calculated actual mobilities and pKa values can be utilised in the optimisation of pH conditions for separation. The practical value of the method was illustrated by the analysis of urine samples. 相似文献