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21.
枸橼酸莫沙必利的合成 总被引:1,自引:0,他引:1
分别以邻羟基对氨基苯甲醇钠,对氟苯甲醛,邻苯二甲酰亚胺为起始原料,制得3个中间体,用其中2个中间体经偶合,环化后与第3个中间体反应,再经成盐制得产品,其摩尔总收率为31.5%。 相似文献
22.
临汾凹陷区主要活动断裂卫星影像分析 总被引:1,自引:0,他引:1
杜云洁 《科技情报开发与经济》2005,15(14):137-138
论述了活动断裂的一般影像特征,对临汾凹陷区主要活动断裂构造的卫星影像进行了分析,从而论证了应用卫星影像可以查明活动断裂的具体特征、力学性质及活动方式等,使人类进一步认识断裂构造的活动规律,将其所造成的自然灾害损失降至最低。 相似文献
23.
本文运用五种竞争作用力理论,具体分析了中国电子工业的微观环境,通过分析可以看出中国电子工业的外部微观环境主要就是电信运营企业和自身合资企业中中外双方的股东企业。这种结果对分析中国电子工业企业的发展简化了环境。 相似文献
24.
杨祖彬 《重庆工商大学学报(自然科学版)》1991,(4)
本文根据缓冲包装五步设计法,包装设计的目的(保护产品、方便储运、促进销售),运输包装的基本要求,探讨了运输包装的设计过程. 相似文献
25.
Agnès Tourin 《Numerische Mathematik》1992,62(1):75-85
Summary The reconstruction from a shaded image of a Lambertian and not self-shadowing surface illuminated by a single distant pointwise light source may be written as a first-order Hamilton-Jacobi equation.In this paper, we continue the investigation begun in E. Rouy and A. Tourin into the uniqueness of the solution of this equation; the approach is based on the viscosity solutions theory and the dynamic programming principle.More precisely, we concentrate here on the uniqueness of the viscosity solution of this equation in case the measured luminous intensity reflected by the surface is discontinuous along a smooth curve. We prove a general comparison result for a piecewise Lipschitz continuous Hamiltonian and illustrate it by numerical experiments. 相似文献
26.
Peng Ping Wenshou Wang Xuesi Chen Xiabin Jing 《Journal of Polymer Science.Polymer Physics》2007,45(5):557-570
Poly(ε‐caprolactone)‐based segmented polyurethanes (PCLUs) were prepared from poly(ε‐caprolactone) diol, diisocyanates (DI), and 1,4‐butanediol. The DIs used were 4,4′‐diphenylmethane diisocyanate (MDI), 2,4‐toluenediisocyanate (TDI), isophorone diisocyanate (IPDI), and hexamethylene diisocyanate (HDI). Differential scanning calorimetry, small‐angle X‐ray scattering, and dynamic mechanical analysis were employed to characterize the two‐phase structures of all PCLUs. It was found that HDI‐ and MDI‐based PCLUs had higher degree of microphase separation than did IPDI‐ and TDI‐based PCLUs, which was primarily due to the crystallization of HDI‐ and MDI‐based hard‐segments. As a result, the HDI‐based PCLU exhibited the highest recovery force up to 6 MPa and slowest stress relaxation with increasing temperature. Besides, it was found that the partial damage in hard‐segment domains during the sample deformation was responsible for the incomplete shape‐recovery of PCLUs after the first deformation, but the damage did not develop during the subsequent deformation. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 557–570, 2007 相似文献
27.
A liquid chromatography-mass spectrometry method for the determination of the coccidiostats metronidazole, ronidazole, dimetridazole,
secnidazole, tinidazole and ipronidazole in feedstuff was developed. The 5-nitroimidazoles were extracted from animal feed
with a pH 2 phosphate buffer solution followed by a solid phase extraction procedure based on HLB cartridges. The liquid chromatographic
separation of the extracts was performed on a C18 bonded silica column applying a gradient of elution with pH 4.3 ammonium acetate buffer solution and acetonitrile. Quantification
for each 5-nitroimidazole was carried out monitoring its molecular ion [M + H]+ obtained by positive electrospray ionisation mode. A pool of feedstuffs was used to optimise and validate the method. Linearity,
quantification limit, intra-day and inter-day reproducibility and accuracy were estimated using this pool of feedstuffs spiked
with the drugs. For the confirmatory assay, several fragment ions from each 5-nitroimidazole were obtained and monitored.
The method was applied successfully to determine 5-nitroimidazoles in feedstuff at level of 0.05 mg kg−1. 相似文献
28.
K. Popov-Pergal L. Cuckovic M. Rancic M. Pergal D. Djokovic 《Chemistry of Heterocyclic Compounds》2003,39(8):1090-1093
A series of methyl 2-(arylidene-2,4-dioxotetrahydrothiazol-3-yl)propionates were prepared. A study of the 3D structure was performed. The log P values are given for all the synthesized compounds. 相似文献
29.
The central zinc(II) atom in the title complex is tetrahedrally coordinated by four nitrogen atoms derived from 4‐methyl‐5‐imidazolecarboxyaldehyde ligands with Zn? N in the range 2.007(3) to 2.026(4) Å. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
30.