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251.
We explore the possibility that the dark matter relic density is not produced by a thermal mechanism directly, but by the decay of other heavier dark-sector particles which themselves can be produced by the thermal freeze-out mechanism. Using a concrete model with light dark matter from dark sector decay, we study the collider signature of the dark sector particles associated with Higgs production processes. We find that future lepton colliders could be a better place to probe the signature of this kind of light dark matter model than hadron colliders such as LHC. Also, we find that a Higgs factory with center-of-mass energy 250 GeV has a better potential to resolve the signature of this kind of light dark matter model than a Higgs factory with center-of-mass energy 350 GeV. 相似文献
252.
We study the symmetric positive semidefinite solution of the matrix equation AX
1
A
T
+ BX
2
B
T
= C, where A is a given real m×n matrix, B is a given real m×p matrix, and C is a given real m×m matric, with m, n, p positive integers; and the bisymmetric positive semidefinite solution of the matrix equation D
T
XD = C, where D is a given real n×m matrix, C is a given real m×m matrix, with m, n positive integers. By making use of the generalized singular value decomposition, we derive general analytic formulae, and
present necessary and sufficient conditions for guaranteeing the existence of these solutions.
Received December 17, 1999, Revised January 10, 2001, Accepted March 5, 2001 相似文献
253.
Guoping Dong Xiudi Xiao Xiaofeng Liu Bin Qian Yang Liao Chen Wang Danping Chen Jianrong Qiu 《Applied Surface Science》2009,255(17):7623-7626
Face-centered cubic Ag porous films have been prepared directly from the heat treatment of AgNO3-doped poly(vinyl alcohol) (PVA) electrospun nanofibers. Using Rhodamine B (RB) as the probing molecule, the surface-enhanced Raman scattering (SERS) effect of Ag porous films was demonstrated. The antibacterial activity of Ag porous films was also studied in this work. The propagation and biological activity of yeast cells were effectively inhibited by Ag porous films. These functional Ag porous films were expected to be applied in many fields, such as catalysis, diagnostics, sensors and antibacterial, etc. 相似文献
254.
255.
A coefficient inverse problem of the one-dimensional parabolic equation is solved by a high-order compact finite difference method in this paper. The problem of recovering a time-dependent coefficient in a parabolic partial differential equation has attracted considerable attention recently. While many theoretical results regarding the existence and uniqueness of the solution are obtained, the development of efficient and accurate numerical methods is still far from satisfactory. In this paper a fourth-order efficient numerical method is proposed to calculate the function u(x,t) and the unknown coefficient a(t) in a parabolic partial differential equation. Several numerical examples are presented to demonstrate the efficiency and accuracy of the numerical method. 相似文献
256.
Yang Li K.W. Wong XiaoFeng Liao ChuanDong Li 《Nonlinear Analysis: Real World Applications》2009,10(3):1712-1716
The issue of impulsive control theory for the synchronization of the nuclear spin generator (NSG) chaotic systems is developed. We propose an impulsive control scheme for the complete synchronization of the NSG system including chaotic systems. A sufficient condition for the impulsive control is derived, with an easily calculated maximum impulsive interval. The proposed impulsive control scheme is applied to the NSG system and the simulation result demonstrates the effectiveness of the method. 相似文献
257.
Zhong Zhengkun Kan Wentao Liao Wei 《Journal of Radioanalytical and Nuclear Chemistry》2019,319(1):453-458
In order to select a chelator with excellent stability, easier radiolabeling process and low cost, GRPr antagonist RM26 with the amino acid based chelator was radiolabeled with technetium-99m. The stability of the radiolabeled peptides in PBS, serum as well as in the presence of excess cysteine was compared.
相似文献258.
对东乡野生稻的越冬性能进行了连续2年的观察,结果表明:东乡野生稻的稻蔸能在武汉地区安全越冬,翌年春季再生苗从地表以下的茎节长出.越冬再生植株与种子实生植株相比并无差异. 相似文献
259.
Blixt O Han S Liao L Zeng Y Hoffmann J Futakawa S Paulson JC 《Journal of the American Chemical Society》2008,130(21):6680-6681
The siglec family of sialic acid binding proteins participates in diverse cell surface biology that includes regulation of immune cell signaling and the interaction of neuronal cells with glial cells. The weak intrinsic affinity of the natural sialoside ligands has hampered the development of synthetic ligand based probes needed to elucidate their roles in siglec function. In this report, we describe a glycan microarray comprising a library of 9-acyl-substituted sialic acids incorporated into sialosides containing the Neu5Acalpha2-3Gal and Neu5Acalpha-6Gal linkages commonly recognized by the siglecs. The array is demonstrated to exhibit utility for detecting 9-acyl substituents that increase the affinity of siglecs for their ligands. Substituents that increase affinity are anticipated to be useful for the design of high affinity ligand based probes of siglec function. 相似文献
260.
Kaltgrad E O'Reilly MK Liao L Han S Paulson JC Finn MG 《Journal of the American Chemical Society》2008,130(14):4578-4579
Glycans arrayed on the exterior of virus particles were used as substrates for glycosyltransferase reactions to build di- and trisaccharides from the virus surface. The resulting particles exhibited tight and specific associations with cognate receptors on beads and cells, in one example defeating in cis cell-surface interactions in a manner characteristic of polyvalent binding. Combined with the ability of viruses to provide structurally well-defined attachment points, the methodology provides a convenient and powerful way to prepare complex carbohydrate ligands for clustered receptors. 相似文献