电子设备安全性评定的关键要素

从主导主体、体现形式、依据原则、强制程度、时效性五个方面,分别介绍了美、日两国对电子设备安全性评定关键要素的选取依据,并对比美、日两国关键要素的差异性,进而对我国电子设备安全性评定的完善提出合理化建议。     

Über die kristall- und molekülstruktur und die absolute konfiguration des (+)-14-epicorynolin-bromacetats

The crystal structure and absolute configuration of ( + )-14-epicorynoline bromoacetate have been elucidated by X-ray diffraction method. The title compound forms monoclinic needles of space group P2₁, with a = 10.056, b = 7.400, c = 13.959 Å, β = 94.09°, and two molecules in the unit cell. The structure was determined by the heavy-atom method and refined by the least-squares method to R =0.082 for 1195 reflections collected by counter diffractometer techniques. Using the anomalous dispersion effect of the bromine atom, the absolute configuration was also determined as 11S, 13R and 14S. The mode of B/C-ring connection is trans; the rings B and C form half-chair and twist-half-chair conformations, respectively. The dihedral angle between the A- and D-rings is 11°. The hydroxyl-group at C-ll is trans to the methyl-group at C-13. The methyl-group at N-5 has an axial orientation and a 1,3-diaxial relationship to the angular methyl-group at C-13, which causes an unusual short distance of 3.11 Å between these methyl-groups.     

Enhanced phosphorescence in intramolecular exciplex systems

Phosphorescence behavior of the series of compounds, (carbazole)-(CH₂)_n-(terephthalic acid methyl ester), which show intramolecular exciplex emission, has been studied in a rigid medium at 77 K. The phosphorescence of the carbazole moiety is enhanced by electron transfer fluorescence quenching of the carbazole residue in accord with the degree of quenching.     

Synthesis of 2,3,4-trideoxy-4-c-(phenylphosphinyl)-dl-glycero-pentofuranose and its 1,5-diacetate

Synthesis of 2,3,4-trideoxy-4-C-(phenylphosphinyl)-dl-glycero-pentofuranose (11) starting from 2-furanmethanol was successful. The reaction of methyl 2,3-dideoxy-(1S)-dl-pentopyranosid-4-ulose 4-(p-toluenesulfonylhydrazone) with methyl phenylphosphonite gave methyl (4RS)-2,3,4-trideoxy-4-C-[(methoxy)phenylphosphinyl]-4-C-(p-toluenesulfonylhydrazino)-(1S)-dl-pentopyranoside (7), which on treatment with sodium borohydride afforded methyl 2,3,4-trideoxy-4-C-[(methoxy)phenylphosphinyl]-(1S)-dl-glycero-pentopyranoside (9). Treatment of compound 9 with SDMA followed by hydrolysis and treatment with acetic anhydride-pyridine afforded 1,5-diacetate 12 of compound 11.     

日本运营商对4G,3G互操作技术的运用

日本是全球最早建设并成熟运营以FDD-UMTS为典型制式的第三代移动通信系统(3G)的国家之一,在新技术运用方面拥有先发优势。2012年10月,日本通信业再次率先迈进了4G商用门槛,各运营商在3G/4G无线网并存的现状下通过缜密有效的运用互操作技术,在实现网络价值的最大化的同时,保障了不同技术世代之间的平稳衔接。这些技术经验值得即将迈入4G时代的中国运营商借鉴。     

日本第三代移动通信的发展

日本邮政省依据国内通信市场的发展速度和第二代移动通信系统的不足，制定了２００１年引入第三代移动通信系统的时间表，同时向ＩＴＵ提交了标准提案。在技术选择上，充分考虑ＣＤＭＡ的技术优势，选择了Ｗ－ＣＤＭＡ的空中接口方案。在核心网方面，日本选择了两种有助于后向兼容的技术。为使第三代系统顺利投入商用，几家运营公司已着手开始现场试验。     

日本生体认证技术及其动向

生体认证技术在人体认证技术手段中得到了越来越多的关注。由于其种类多,认证结果可靠等优点,在众多领域都得到了应用。本文从生体认证的必要性、研究历史、认证技术的特点及种类、应用市场与将来预测、现实问题和展望等方面概述了日本生体认证技术及其动向。     

Stereoselective preparation of methylenecyclobutane-fused angular tetracyclic spiroindolines via photosensitized intramolecular [2+2] cycloaddition with allene

Irradiation of 3-(hexa-4,5-dienyl)indole derivatives in the presence of 3′,4′-dimethoxyacetophenone by a high-pressure mercury lamp through Pyrex glass gave the corresponding [2+2] cycloaddition products stereoselectively in high yields. The major product was a methylenecyclobutane-fused angular tetracyclic spiroindoline derivative produced by the [2+2] cycloaddition through a parallel orientation. The minor product was a hexahydromethanocarbazole derivative through a crossed orientation. Electron-withdrawing substituents, such as acyl or alkoxycarbonyl, on the indole nitrogen were suitable for this reaction.     

Boat and chair benzenes incorporated in cyclophanes

Various modes of the out-of-plane deformation of a benzene ring have been examined theoretically the MINDO/2 methods. Deformation to the boat conformation is predicted to be more facile than that to the half-boat or the chair conformation as observed in triple-layered[2.2]-metacyclophanes. The energy partitioning analysis reveals that a minimal loss of resonance energy at the gunwale of benzene boats appears to be responsible for the ease of boat deformations. The out-of-plane bending of the H atom at the bow of die benzene boats is coupled to the displacement of the H at the gunwale in such a way that the torsion of the bond between the bow and gunwale C atoms may be kept as small as possible.     

Stereoselective synthesis of dinucleoside phosphate aryl esters by using new condensing reagents,arenesulfonyl 5-(pyridin-2-yl)-tetrazole1

Deoxyadenylyl-(3'-5')-phosphoro-o-chlorophenyl deoxyadenosine having the Sp configuration was synthesised stereoselectively by condensing N,5'-bis-dimethoxytrityldeoxyadenosine 3'-(o-chlorophenyl) phosphate with N,3'-bis-dimethoxytrityldeoxyadenosine using 1-2,4,6-triisopropylbenzene-5-(pyridin-2-yl) tetrazole as the activating reagent followed by dedimethoxytritylation. The absolute configuration of this diastereomer was determined spectroscopically by comparison of two corresponding diastereomers which were prepared by using a conventional condensing reagent and isolated by chromatography on silica gel. Their nuclear Overhauser effect in proton magnetic resonances and the circular dichroism of these two diastereoisomers could only be explained if the product obtained by the stereoselective synthesis had Sp configuration. Our results also suggest that phosphotriesters of this type exist in solution as an equilibrium of folded and extended forms.