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61.
If the supersymmetry (SUSY) is a solution to the hierarchy problem, it is puzzling that any SUSY particle has not been discovered yet. We show that there is a low-scale conformal gauge mediation model which contains all necessary ingredients, i.e. not only a SUSY-breaking dynamics and a gauge mediation mechanism, but also a candidate for the dark matter. The model has only one free mass parameter, that is, the mass for messengers. In this model, the dark matter is provided by a composite particle in the SUSY-breaking sector, and the observed value of the dark matter density uniquely fixes the mass of messengers at the order of 102 TeV. Then, the sfermion and gaugino masses are fixed to be of order 102–103 GeV without any arbitrariness, thus the SUSY particles are expected not to be discovered at the Tevatron or LEP, while having a discovery possibility at the LHC. 相似文献
62.
Sibo Zheng 《Nuclear Physics B》2012,855(2):320-332
Supersymmetric models based on the scenario of gauge mediation often suffer from the well-known μ problem. In this paper, we reconsider this problem in low-scale gauge mediation in terms of effective field theory analysis. In this paradigm, all high energy input soft mass can be expressed via loop expansions. If the corrections coming from messenger thresholds are small, as we assume in this letter, then all RG evaluations can be taken as linearly approximation for low-scale supersymmetric breaking. Due to these observations, the parameter space can be systematically classified and studied after constraints coming from electro-weak symmetry breaking are imposed. We find that some old proposals in the literature are reproduced, and two new classes are uncovered. We refer to a microscopic model, where the specific relations among coefficients in one of the new classes are well motivated. Also, we discuss some primary phenomenologies. 相似文献
63.
模糊判断矩阵一致性的调整方法 总被引:19,自引:0,他引:19
给出了模糊判断矩阵一致性调整的新方法 .该方法是在模糊判断矩阵一致性定义及判定方法的基础上 ,通过构造和分析模糊判断矩阵的调和矩阵 ,进一步给出了将模糊判断矩阵改进为满意一致性矩阵的计算步骤 .最后给出了一个算例 . 相似文献
64.
N‐Linked Glycosyl Auxiliary‐Mediated Native Chemical Ligation on Aspartic Acid: Application towards N‐Glycopeptide Synthesis 下载免费PDF全文
Hua Chai Dr. Kim Le Mai Hoang Minh Duy Vu Dr. Kalyan Pasunooti Prof. Dr. Chuan‐Fa Liu Prof. Dr. Xue‐Wei Liu 《Angewandte Chemie (International ed. in English)》2016,55(35):10363-10367
A practical approach towards N‐glycopeptide synthesis using an auxiliary‐mediated dual native chemical ligation (NCL) has been developed. The first NCL connects an N‐linked glycosyl auxiliary to the thioester side chain of an N‐terminal aspartate oligopeptide. This intermediate undergoes a second NCL with a C‐terminal thioester oligopeptide. Mild cleavage provides the desired N‐glycopeptide. 相似文献
65.
We constructed an electrochemical sensor based on an electrode modified with electron-transfer, carbohydrate-mimetic peptides on collagen film. The peptide consisted of Ac-Y4C combined with soybean agglutinin (SBA). To evaluate the binding between SBA and the peptide, we prepared Ac-Y4CAn (3-6) containing oligoalanine as a cross-linker. When SBA and Y4C on the electrode were incubated, the peak was decreased by the SBA uptake of the peptide. The change in the peak current using Ac-Y4CA6 was the greatest of the four peptides. The calibration curve was linear and ranged from 4.0×10−14 to 1.2×10−12 M with a detection limit of 1.3×10−14 M. 相似文献
66.
In the presence of iodine, a mixture of dichloromethane, iodoalkanes (alkyl = Me, Et, Pr, iso-Pr, Bu, iso-Bu, pentyl) and aluminum powder was irradiated at room temperature with ultrasound to give readily chloroiodomethane ICH2Cl. The preferred reactant to give the best yield of ICH2Cl was PrI. Alkylaluminum sesqui-iodides were postulated as intermediates. 相似文献
67.
本工作合成了一组带不同取代基的氧鎓盐化合物,并对它们的荧光寿命、荧光量子产率以及用丁基乙烯基醚(BVE)进行猝灭的荧光猝灭常数进行了测定,发现带拉电子基的氧鎓盐化合物和BVE间存在着较强的相互作用,相反,推电子基的引入则减弱了这种影响,表明反应具有电子转移性质.由于在BVE的聚合过程中,被猝灭的氧鎓盐荧光会因BVE聚合、双键减少而使氧鎓盐荧光逐步恢复.因此利用这一现象作为荧光探针,考察了氧鎓盐光引发BVE的阳离子聚合过程.文中还对氧鎓盐光引发BVE聚合的机理进行了初步讨论. 相似文献
68.
Xiang-Yuan Li Quan Zhu Lin-Lin Zhao Shun-Qing Xiao Feng Liu 《Theoretical chemistry accounts》2002,107(5):282-290
Based on the spherical cavity approximation and the Onsager model, a dipole–reaction field interaction model has been proposed
to elucidate the solvent reorganization energy of electron transfer (ET). This treatment only needs the cavity radius and
the solute dipole moment in the evaluation of the solvent reorganization energy, and fits spherelike systems well. As an application,
the ET reaction between p-benzoquinone and its anion radical has been investigated. The inner reorganization energy has been calculated at the level
of MP2/6–31+G, and the solvent reorganization energies of different conformations have been evaluated by using the self-consistent
reaction field approach at the HF/6–31+G level. Discussions have been made on the cavity radii and the values are found to
be reasonable when compared with the experimental ones of some analogous intramolecular ET reactions. The ET matrix element
has been determined on the basis of the two-state model. The fact that the value of the ET matrix element is about 10 times
larger than RT indicates that this ET reaction can be treated as an adiabatic one. By invoking the classical Marcus ET model, a value of
4.9 × 107M−1s−1 was obtained for the second-order rate constant, and it agrees quite well with the experimental one.
Received: 19 October 2001 / Accepted: 17 January 2002 / Published online: 3 May 2002 相似文献
69.
A. Kaddouri I. Ashraf M. Ait El Fqih H. Targaoui A. El Boujlaïdi K. Berrada 《Applied Surface Science》2009,256(1):116-119
The effect of oxygen on the light emission from a Si (1 0 0) semiconductor bombarded by energetic Kr+ ions has been studied in the 200–300 nm wavelength range. The influence of oxygen was verified by studying the optical spectra of SiO2 bombarded under similar experimental conditions. It has been found that the measured intensities of the emitted photons are always higher in the presence of oxygen, even higher than those obtained for SiO2. The electron-transfer model can explain our experimental observations. We do believe that in the presence of oxygen, an intermediate structure of silicon sub-oxide SiOX<2 is formed on silicon surface, which is responsible for the increase of photon emission. In addition, the radiative dissociation process and breaking of chemical bond seems contribute to the enhancement of emitted photons intensity. 相似文献
70.
It is generally believed that the low energy effective theory of the minimal supersymmetric standard model is the type 2 two Higgs doublet model. We will show that the type 1 two Higgs doublet model can also be as the effective of supersymmetry in a specific case with high scale supersymmetry breaking and gauge mediation. If the other electroweak doublet obtain the vacuum expectation value after the electroweak symmetry breaking, the Higgs spectrum is quite different. A remarkable feature is that the physical Higgs boson mass can be 125 GeV unlike in the ordinary models with high scale supersymmetry in which the Higgs mass is generally around 140 GeV. 相似文献