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71.
Electron density distributions of 2-aminoethanol (2AE) and 2-amino-l-propanol (2AP) are calculated in both the coordinate and the momentum spaces using the B3LYP/TZVP method. Using the dual space analysis, molecular orbital signatures of the methyl substituent in 2AP are identified with respect to 2AE. Relaxations of the geometry and the valence orbital in 2AP are found to be due to the insertion of the methyl group. Five orbitals, not four orbitals, are identified as the methyl signatures. They are orbital 5a in the core shell, orbitals 9a and 10a in the inner valence shell, and orbitals 15a and 16a in the outer valence. In the inner valence shell, the attachment of methyl to 2AE causes a splitting of its orbital 8a into orbitals 9a and 10a of 2AP, whereas in the outer valence shell, the methyl group results in the insertion of an additional orbital pair of 15a and 16a. The frontier molecular orbitals 21a, 20a, and 19a are found to have no significant role in the methylation of 2AE.  相似文献   
72.
Seven experimentally observed bands of 155Tb are analyzed in detail,using the particle-number-conserving method for treating the cranked shell model with monopole and quadrupole pairing interactions.We satisfactorily reproduce the experimental alignments and especially focus on the microscopic mechanism of the second back-bending and the influence of pair interaction on ultrahigh spins.Our calculated results show that the πi13/2 orbitals are too high to give a contribution to the moment of inertia below ω≈ 0.7 MeV.Instead,the crossing between the π[541]1/2 and other proton orbitals is responsible for the second back-bending.We assign a possible configuration to the decoupled band found in 155Tb and predict eleven bands which are experimentally unobserved.  相似文献   
73.
Changes of molecular structure and associated charge distributions, and changes of anharmonic vibrational parameters from DNA base monomers to the Watson-Crick base pairs, have been investigated at the density functional theory level. Through examination of the NH2, N H, and C=O stretching vibrational modes that are involved in the multiple H-bonds in the base pairs, sensitivity of their diagonal and off-diagonal anharmonicities, as well as anharmonic vibrational couplings, to the structure change are predicted. Our results reveal the intrinsic connection between the anharmonic vibrational potentials, H-bonding, and electrostatic interactions in DNA bases.  相似文献   
74.
李晓滨 《光子学报》2006,35(12):1899-1902
图像传输和接入要求系统的吞吐量超过Gb/s,若采用常规光码分多址系统来实现图像传输,对光电器件的要求高、实现难度大,解决方案是采用光码分多址并行图像传输系统.针对并行图像传输的签名序列是一种二维光正交签名图形,是一种全新形式的签名码,构造最大容量的光正交签名图形(最佳光正交签名图形)的方法很少这一问题,提出一种区组设计构造算法.算法的思想是根据差集合和光正交码的关系,将差集合和区组设计的概念推广到二维空间,根据二维差集合和光正交签名图形的关系从而构造出最佳光正交签名图形.详细阐述了构造最佳光正交签名图形的步骤,对算法进行了仿真.仿真结果说明该算法可以有效地构造出最佳光正交签名图形.  相似文献   
75.
76.
High spin states in odd-odd ^98 Tc nuclei are studied by in-beam γ-ray spectroscopy with the ^96 Zr(^6Li, 412) fusionevaporation reaction at a beam energy of 35MeV. The previous level scheme is updated. A band based on 1090.7keV is expanded, and another band based on 1920.6 keV is newly identified. The observed two negative parity bands in ^98 Tc are proposed to be a pair of chiral doublet bands with the configuration πg9/2 vh11/2. The evidence supporting the assignment of the chiral doublet bands is discussed. Signature splitting and signature inversion are observed in the πg9/2 vh11/2 band in ^98Tc.  相似文献   
77.
李渊华  刘俊昌  聂义友 《光子学报》2010,39(9):1616-1620
利用量子隐形传态原理和量子纠缠交换技术,提出了基于W态的跨中心量子网络身份认证方案,实现了分布式量子通信网络中对客户的身份认证.该方案分为注册阶段和身份认证阶段,认证系统包括主服务器和客户端服务器.客户所有的操作都在客户端服务器上进行,不直接与主服务器进行通信.身份认证全部由服务器根据量子力学原理进行,保证了认证方案的安全性.最后,对该方案进行了安全性分析.  相似文献   
78.
79.
Unconditionally secure signature is an important part of quantum cryptography. Usually, a signature scheme only provides an environment for a single signer. Nevertheless, in real applications, many signers may collaboratively send a message to the verifier and convince the verifier that the message is actually transmitted by them. In this paper, we give a scalable arbitrated signature protocol of classical proved to be secure even with a compromised arbitrator. messages with multi-signers. Its security is analyzed and proved to be secure even with a compromised arbitrator.  相似文献   
80.
兰剑 《广西物理》2006,27(3):52-53,55
简述当前电子订单业务系统的安全问题,研究了如何利用PKI(公钥基础设施)技术来实现安全需求中的身份认证、数据传输以及不可抵赖的安全,最后给出具体的解决方案。  相似文献   
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