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排序方式: 共有86条查询结果,搜索用时 62 毫秒
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SOLIMAN A.Y. BAKEER H.M. ATTIA LA.Science Department Faculty of Teachers P.O.Box Alhasa Saudi Arabia Chemistry Department Faculty of Science Fayoum Cairo University EgyptFaculty of Engineering Ain Shames University Egypt 《中国化学》1996,14(6):532-540
3-(4-Phenyl) benzoyl propionic acid was used as the starting material for the synthesisof furanones (2), pyrrolinones (5), pyridazinones (7), benzoxazinones (8) and quinazolinones (9-11). The behaviour of the derivatives of furanones and benzoxazinones toward different nucleophiles is reported. 相似文献
3.
Ananthakrishnan Gunasekaran Thiruvalam Jayachandran Joseph H. Boyer Mark L. Trudell 《Journal of heterocyclic chemistry》1995,32(4):1405-1407
The reaction of glyoxime ( 4 ) and hydroxylamine hydrochloride in aqueous sodium hydroxide was found to be a safe and inexpensive method for the preparation of multigram quantities of diaminoglyoxime ( 5 ). Potassium hydroxide mediated dehydration of 5 furnished diaminofurazan ( 1 ) in good yield of exceptional purity. The ready availability of 1 and 5 has facilitated the synthesis of new energetic furazan derivative 8 . 相似文献
4.
J. R. Trudell S. D. Sample Woodgate Carl Djerassi 《Journal of mass spectrometry : JMS》1970,3(6):753-776
Chroman (I), 2,2-dimethylchroman (II), flavan (III) and 2,2-diphenylchroman (IV) were labeled with 13C or deuterium at every position of importance. The mass spectra of these labeled compounds make possible a detailed interpretation of some very complex carbon skeleton rearrangements. The combination of deuterium and 13C-labeling revealed that loss of CH3, C2H5 and C7H7 fragments from chroman (I), 2,2-dimethylchroman (II) and 2,2-diphenylchroman (IV) respectively, occurs by multiple pathways involving aryl or alkyl migrations with little hydrogen randomization prior to fragmentation. Although ejection of C7H7 from flavan (III) occurs to a small extent by a route similar to those mentioned above, its [M ? C7H7] fragment can also be formed by a pathway involving no phenyl migration but extensive hydrogen scrambling. The validity of the schemes proposed on the basis of the 13C labeling data was checked by using them to predict the spectra of the deuterium labeled compounds. 相似文献
5.
MENG Jian REN Yu-Fang LI Xiao-GuangLaboratory of Rare Earth Chemistry Physics Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun Jilin ChinaPopov V.V. Repin S.M. Smirnov LA. loffe Physicotechnical Institute Russian Academy of Sciences Saint Petersburg Russia 《中国化学》1994,12(5):419-424
YBa2Cu3-xVxO7-y(x=0, 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6) superconductors have been prepared. X-ray diffraction shows that the system remains orthorhombic for all compositions studied, but for x > 0.4 V2O5 was detected as an impurity phase. Substitution of V5+ for Cu2+ occurs in the Cu(2) sites on the Cu(2)-O planes. The introduction of the high valence element, vanadium, produces the extra free-electrons. These electrons recombine with the positive carrier of the system. It makes depression of the mobility and the Hall number of YBa2Cu3-xVxO7-v and also results in a depression of TC. 相似文献
6.
MARIAN ELBANOWSKI MARIA PAETZ JANUSZ SIAWINSKI LESZEK CIELA 《Photochemistry and photobiology》1988,47(3):463-466
Abstract— Chemiluminescence of the Eu(II)/Eu(III)-adenine nucleotide-H2 O2 system and fluorescence of the Eu(III)-adenosine triphosphate system have been investigated. The spectral distribution of the chemiluminescence emission has shown an occurrence of three main bands (Λ=470–480,590–620 and ca. 700 nm). The energy transfer process from the adenosine triphosphate molecules to the Eu(III) ions has been observed in the fluorescence spectrum. The examined chemiluminescence and fluorescence spectra show that these both kinds of emission originate from the 5 D *** τ7 F*** ( n =1–4) transitions in the Eu(III) ions. 相似文献
7.
针对纤维材料变温环境力学性能测试的需要,在华中科技大学研制的纤维材料试验机的基础上引入了温控装置,从而实现纤维材料在高低温环境下的力学性能测试。采用该装置对不同直径微米铜丝在不同温度、不同拉伸速率条件下的力学性能开展实验研究,测试结果表明弹性模量和抗拉强度随温度的降低而线性增加,屈服强度的变化不太明显。另外,低温环境下微米铜丝的力学性能表现出与其直径相关的尺度效应,而这一现象在常温下一直没有观测到。最后,还研究了拉伸速率对微米铜丝的力学性能影响,结果表明,在现有装置的许用范围之内,拉伸速率对其力学性能的影响不大。 相似文献
8.
9.
This paper deals with robustness of adaptive control of continuoussystems subject to known output delay, input saturation, unmodelledlinear dynamics, and bounded disturbances. A simple gradient-typealgorithm with a relative deadzone is used. The relative deadzoneis built with an estimated contribution of the unmodelled dynamicsto the system output. The basic tool used for stability androbustness analysis is Gronwall's lemma. 相似文献
10.
Alexander K. Zelenin Mark L. Trudell Richard D. Gilardi 《Journal of heterocyclic chemistry》1998,35(1):151-155
The synthesis of dinitroazofurazan ( 3 ) was achieved from readily available diaminofurazan ( 6 ) in two steps and 20% overall yield. The structure of the energetic material 3 was unequivocally confirmed by X-ray crystallography and found to have a crystal density of 1.742 g/cm3. 相似文献