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排序方式: 共有209条查询结果,搜索用时 77 毫秒
1.
2.
秦俊法 《广东微量元素科学》1995,(7)
用能量色散X射线荧光分析法测定了某厂生产的44种彩色油墨纸中的铅含量.结果发现,除5种油墨外,其它39种彩色油墨纸中的铅含量均比对照纸中高9倍以上,其中桔黄色、桔红色树脂胶版油墨高500倍以上,棕色树脂胶版油墨高379倍,深黄色和柠檬黄色树脂铅印油墨分别高170和113倍.这表明,彩色油墨印刷品可能是儿童慢性铅中毒的重要污染源. 相似文献
3.
H. Sato A. Bensalah N. Solovieva A. Beitlerova A. Vedda M. Martini M. Nikl T. Fukuda 《Radiation measurements》2004,38(4-6):463-466
Two-inch sized KMgF3,BaLiF3 and LiCaAlF6 (LiCAF) single crystals were grown by the Czochralski method under a CF4 atmosphere. X-ray irradiation was used to carry out a comparative study of induced optical absorption phenomena and colour centre creation in the ultra-violet and visible spectral regions. The integral of the induced absorption spectra is significantly lower in LiCAF with respect to the other studied materials. It is found that the amplitude of the F-absorption band is suppressed more than a factor of 3 by Mg-doping. For Mg-doped crystals, the optimum doping concentration is about 0.2 mol% of Mg2+. 相似文献
4.
We study the aggregation of oxygen dipoles well dispersed in a CaF2 crystal upon annealing at temperatures ranging from 370 to 420 K. The concentration of oxygen dipoles is monitored by measuring the intensity of the ionic thermocurrent peak as well as by absorption and luminescence spectroscopies. Results from three methods agree within experimental error and yield an activation energy of (1.2±0.1) eV for the diffusion of isolated oxygen centres in the crystal. 相似文献
5.
Kenji Okada 《Journal of Molecular Structure》1996,380(3):223-233
The crystal and molecular structures of 2,2-bis(4-hydroxyphenyl)propane (Bisphenol A, BPA) (1), benzyl 4-hydroxybenzoate (2), 1,7-bis(4-hydroxyphenylthio)-3,5-dioxaheptane (3) and 4-hydroxyphenyl 4-isopropoxyphenyl sulfone (4) have been determined by X-ray crystal structure analysis. Theoretical calculations of the steric hindrance and semiempirical quantum chemical calculations to determine the color characteristics have been carried out. It is clear that the energy barriers for the variation of the orientation of phenol group in 1 to 4 are due to steric hindrance caused by the other moiety and the peak profiles are due to repulsive interactions of the other moiety. Net atomic charges on the hydrogen of the OH group are larger than those on the other atoms in the molecules. This high electron charge of the para orientation will cause the different thermosensitivity and stabilization. 相似文献
6.
In this article, the results of calculations of scattering spectra of low-absorptive spherical particles are presented. It was obtained using different approximate and numerical methods. The comparative evaluations of application of single scattering approximation, the average field approximation and of the methods of computer modeling on the basis of Monte-Carlo method on various scattering multiplicity were performed. The comparison demonstrates the good agreement of calculated results with experimental scattering spectra of eye lens. By using the obtained spectral data the colour coordinates are calculated. The regularities of changes in colour characteristics in dependence of disperse system parameters are analyzed. 相似文献
7.
超高感彩卷乳剂微晶体电镜研究 总被引:1,自引:0,他引:1
应用物理和化学相结合的方法,将超高感彩卷分层剥离,离心沉降,水洗除胶,电镜观测各层乳剂的微晶体结构。揭示了超高感彩卷各乳剂层的结构情况,披露了超高感彩剂制造技术。 相似文献
8.
聚乙烯醇存在下锇(Ⅱ)-氯化亚锡-结晶紫体系超高灵敏显色反应的研究 总被引:1,自引:0,他引:1
本文研究了聚乙烯醇存在下锇(Ⅱ)-氯化亚锡-结晶紫体系的超高灵敏显色反应。反应物λ_(max)=555nm,ε_(555)=1.52×10~6L·mol~(-1)·cm~(-1)。锇含量为(0~4.8)μg/25ml时符合比尔定律。对共存离子的干扰和分离进行了实验,拟定的方法可用于矿石和一些含低品位锇物料的分析。 相似文献
9.
Takashi Kajiwara Kensuke Katagiri Shinya Takaishi Masahiro Yamashita Nobuhiko Iki 《化学:亚洲杂志》2006,1(3):349-351
A dodecaholmium wheel of [Ho12(L)6(mal)4(AcO)4(H2O)14] ( 1 ; mal=malonate) was synthesized by using p‐tert‐butylsulfonylcalix[4]arene (H4L) as a cluster‐forming ligand. The wheel consists of three fragments of mononuclear A3? ([Ho(L)(mal)(H2O)]3?), trinuclear B3? ([Ho(H2O)2(mal)(Ho(L)(AcO))2]3?), and C3+ ([Ho(H2O)2]3+), and an alternate arrangement of these fragments (A3?? C3+? B3?? C3+? A3?? C3+? B3?? C3+? ) results in a wheel structure. The longest and shortest diameters of the core were estimated to be 17.7562(16) and 13.6810(13) Å, respectively, and the saddle‐shaped molecule possesses a pocketlike cavity inside. 相似文献
10.
聚合物与有机染料多层复合膜电致发光颜色的直流电压调制马於光,薛善华,黄劲松,田文晶,刘式墉,沈家骢,刘晓冬(吉林大学分子光谱与分子结构开放实验室,集成光电子学国家重点实验室,长春,130023)(白求恩医科大学,长春,130023)关键词聚合物,发光... 相似文献