当前公开密钥基础设施的主要问题分析

PKI作为一种网络安全基础设施，日益受到关注，但是PKI还有许多问题有待解决，文章首先由信任的定义及其数学属性入手，指出PKI先天固有的不足，然后指出各种PKI系统都具有的问题，当前现有标准X．509，PGP，SPKI／SDSI的各自缺陷。     

On‐site Raman and XRF analysis of Japanese/Chinese bronze/brass patina – the search for specific Raman signatures

The assignment of Asian bronzes and brasses is difficult because the copies of ancient pieces have been made a long time ago in different countries. A selection of 30 Japanese and/or Chinese bronzes/brasses are studied on‐site in the storage and exhibition rooms of the Cernuschi Museum, in Paris, using portable Raman and X‐ray fluorescence spectrometers. Attempts are made to identify specific Raman signatures of the patina to detect similarity in a nondestructive procedure. X‐ray fluorescence measurements allow an identification of two brass artefacts and different types of bronze, including lead‐rich and mixed lead–tin–zinc‐rich compositions. The following phases are identified: CuO, Cu₂O, Cu₂S, tin oxides, ZnO, Cu₃(OH)₄SO₄, Cu₄(OH)₆SO₄, 3PbOPbSO₄ H₂O, PbSO₄/PbO, Pb(AsO₄)₃Cl, HgO/HgS. Relics of the mould, retained as concretions at the artefact surface are also identified: TiO₂, SiO₂, and different soda(−lime) glasses. Patina with very similar colour and habit may have different Raman signatures. This study offers tools to classify the artefacts in a noninvasive way. Copyright © 2011 John Wiley & Sons, Ltd.     

日本长期使用产品检修制度介绍

2009年4月1日,日本“长期使用产品安全检修制度”正式实施。对该制度的宗旨、对象产品和制度具体要求等进行了详细介绍,并提出了我国企业和有关政府部门等应采取的应对措施。     

Theoretical studies of molecular complexes: a probe into basis set and correlation effects

We investigate the effect of basis set size, correlation effects and interplanar separation on the theoretical electronic structure of stacking complexes of para- and meta-hydroxyaruline with formamidinium cation, constructed as analogs for the complexes of 5- and 6-hydroxytryptamine with imidazolium cation.     

Synthesis of mevalonolactone (hiochic acid lactone) employing asymmetric epoxidation as the key-step

(R)( — )-Mevalonolactone (hiochic acid lactone)of 91–93%e.e. was synthesized from an achiral starting material employing the Sharpless asymmetric epoxidation as the key-step.     

General theory of vibrational mode mixing and frequency shifts in resonance raman scattering

A general formalism is given for treating vibrational mode mixing, frequency shifts, and atomic equilibrium position shifts under electronic excitation in resonance Raman scattering. The theory is exact for first-order scattering at T = 0 K for all linear and quadratic electron-phonon coupling strengths. Numerical results illustrating mode mixing are presented.     

The infrared and Raman spectra of pyromellitic dianhydride

The infrared and Raman spectra of solid state samples of pyromellitic dianhydride have been measured. The infrared—Raman mutual exclusion rule has been observed and the frequencies have been tentatively assigned on the basis of D_2h symmetry. The values of the CO and skeletal ring stretching frequencies have been interpreted in terms of a conjugated π-system.     

Application of multiconfigurational many-body perturbation theory to the calculation of ionization potentials,electron affinities and excitation energ

Multiconfigurational many-body perturbation theory is applied to the problem of calculating ionization potentials, electron affinities, and excitation energies. H₂O, C₂H₄, and H₂ are studied, with correlation corrections through third order and inclusive of certain higher-order terms. Results are compared with those by other many-body theoretical methods.     

Vibrational spectra of cyclobutanecarbonyl chloride and bromide and their α-deuterated compounds

The IR spectra of cyclobutanecarbonyl chloride and bromide and their α-deuterated compounds have been recorded in the vapor, liquid and crystal states. The Raman spectra have also been measured in the liquid state. Comparison of the spectra in the liquid phase with those in the crystal phase reveals that these acyl halides exist in a conformational equilibrium in the liquid state. Tentative vibrational assignments are proposed on the basis of the isotope effect and previous published results for other simple cyclobutane compounds.