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排序方式: 共有1893条查询结果,搜索用时 15 毫秒
1.
《Surface and interface analysis : SIA》2003,35(4):395-402
Two different types of plasticized poly(vinyl chloride) (PVC) used for biomedical disposable devices—extruded and injection moulded—were studied in the non‐sterilized condition and after 25 and 50 kGy of beta irradiation. The polymer surfaces were analysed by scanning electron microscopy (SEM) equipped with an x‐ray energy‐dispersive spectroscopy (XEDS) and by atomic force microscopy (AFM). The inner surface of two parts of a venous line showed a different morphology according to their original formulation (for extrusion or injection moulding process) and reacted differently on sterilization with beta irradiation. Moulded parts were affected only slightly by the radiation step, whereas the variations were bigger for the extruded parts. In order to gain the best performances for the medical devices studied, the utmost care must be taken in the sterilization step, which should be optimized as well as the other steps of the manufacturing process. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
2.
Gwang Hui Kim 《Journal of Mathematical Analysis and Applications》2004,299(2):375-391
In this paper we investigate a generalization of the Hyers-Ulam-Rassias stability for a functional equation of the form f(φ(X))=?(X)f(X)+ψ(X) and the stability in the sense of Ger for the functional equation of the form f(φ(X))=?(X)f(X), where X lie in n-variables. As a consequence, we obtain a stability result in the sense of Hyers-Ulam-Rassias, Gǎvruta, and Ger for some well-known equations such as the gamma, beta, and G-function type's equations. 相似文献
3.
Shy-Der Lin 《Journal of Mathematical Analysis and Applications》2004,294(2):399-411
The main object of this paper is to investigate several general families of hypergeometric polynomials and their associated single-, double-, and triple-integral representations. Some known or new consequences of the general results presented here, involving such classical orthogonal polynomials as the Jacobi, Laguerre, Hermite, and Bessel polynomials, and various other relatively less familiar hypergeometric polynomials, are also considered. Each of the integral representations, which are derived in this paper, may be viewed also as a linearization relationship for the product of two different members of the associated family of hypergeometric polynomials. 相似文献
4.
M. Zendehdel A. Mobinikhaledi F. Hasanvand Jamshidi 《Journal of inclusion phenomena and macrocyclic chemistry》2007,59(1-2):41-44
Transition metal/Y zeolites were prepared using microwave solid state and aqueous solution ion exchange methods. The activity
of these zeolites was investigated in a conversion of acids to benzimidazoles reaction between 4-methyl-1, 2-phenylenediamine and 3-nitrobenzoic acid. The yield of these reactions increased in order of CuY < Fe2+Y < NiY < CoY < NaY < CrY < MnY < ZnY for both methods. The solid state ion-exchanged zeolites showed higher activity in comparison
to the aqueous solution exchange. Yields of products in the presence of the ZnY zeolite were of the order of 69–83%. It seems
that the Lewis sites are better sites compared to the Bronsted sites for this reaction. 相似文献
5.
分子筛负载席夫碱钴配合物的制备及其催化氧气氧化环己烷 总被引:1,自引:0,他引:1
采用柔性配位法将双水杨醛叉乙二胺合钴(Cosalen)封装到了NaY分子筛的超笼中,采用FT-IR,UV-Vis,XRD,TG/DTA 和 BET比表面积及孔容分析对负载型配合物(Cosalen-NaY)进行了表征.在催化氧气氧化环己烷的反应过程中,Cosalen-NaY能有效地促进环己基过氧化物的分解,在0.85 MPa的氧压下,150 ℃反应3 h,环己烷的转化率达到13.4%,在反应体系中加入乙腈作溶剂,130 ℃下进行反应,环己烷的转化率提高到{28.3%.产物中环己醇、环己酮、己二酸的选择性明显高于Cosalen为催化剂的反应.催化剂回收实验表明Cosalen-NaY经过三次重复使用后,没有显著的活性组分流失,可以重复使用. 相似文献
6.
T. Katsuki 《Russian Chemical Bulletin》2004,53(9):1859-1870
The recent development of asymmetric Baeyer—Villiger oxidation of prochiral and racemic ketones is briefly summarized, focusing on the regio- and stereocontrol of the oxidation attained by regulating the stereoelectronic demand in the step of rearrangement of the Criegee intermediate.Based on the report presented at the International Conference Modern Trends in Organoelement and Polymer Chemistry dedicated to the 50th anniversary of the A. N. Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences (Moscow, May 30–June 4, 2004).Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1784–1794, September, 2004. 相似文献
7.
Sb/ZSM-5 was obtained by solid-state reaction with the mixture of Sb2O3 and zeolite HZSM-5 under a dry nitrogen flow at 773 K. Characterization of the treated zeolite was undertaken with XRD, 27Al MAS NMR, BET, TGA and FT-IR. The results revealed that part of the antimony oxides migrated into the channels of zeolite, and decreased the Brönsted acid sites in Sb/ZSM-5 remarkably. The other part of antimony oxides together with the amorphous alumino-silicate in the products distributed on the external surface of zeolite ZSM-5 and modified it, while the framework of ZSM-5 in crystal phase was retained. The structure of occluded antimony oxide inside the channels of ZSM-5 was studied by XRD Rietveld method. The result showed that their structure can be described as a chain of non-perfect [Sb5O5(H2O)2]n5n+, which is parallel to the straight channel of ZSM-5. There is about 0.6 [Sb5O5(H2O)2]5+ unit in every cell of the ZSM-5 on an average. 相似文献
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