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131.
Dark sector may couple to the Standard Model via one or more mediator particles.We discuss two types of mediators:the dark photon A’and the dark scalar mediatorΦ.The total cross-sections and various differential distributions of the processes e+e-→qqA’and e+e→qqφ(q=u,d,c,s and b quarks)are discussed.We focus on the study of the invisible due to the cleaner background at future e+e-colliders.It is found that the kinematic distributions of the two-jet system could be used to identify(or exclude)the dark photon and the dark scalar mediator,as well as to distinguish between them.We further study the possibility of a search for dark photons at a future CEPC experiment with s1/2=91.2 GeV and 240 GeV.With CEPC running at s1/2=91.2 GeV,it would be possible to perform a decisive measurement of the dark photon(20 GeV相似文献
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133.
Transport in Porous Media - Permeability, one of the most significant parameters for CBM, is affected by many influencing factors. In this paper, an improved fully coupled permeability model was... 相似文献
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135.
Single-crystalline and monodisperse LaF3 triangular nanoplates from a single-source precursor 总被引:3,自引:0,他引:3
Single-crystalline and monodisperse LaF3 triangular nanoplates (2.0 x 16.0 nm) in trigonal tysonite structure were synthesized by the thermolysis of a single-source precursor (SSP), La(CF3COO)3, in a hot oleic acid/octadecene solution. The combined use of SSP and coordinating and noncoordinating solvents was demonstrated to have played key roles in the formation of such high-quality nanoplates, which could spontaneously organize into two types of superlattices (edge-to-edge and face-to-face) on a large area. This SSP approach has advantages of one-step, mass production, and easy operation, and may represent a rather general route toward metal fluoride nanocrystals. 相似文献
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137.
The reactions of LnCl3·6H2O (Ln=Eu or Dy) and Na2[Mo2O3S(HNTA)2]·6H2O afford Na[Mo2O3S(HNTA)2]2·Eu(H2O)9·3H2O (1) (NTA=nitrilotriacetate) and Na{(H2O)6Dy[Mo2O3S(HNTA)2]2}·7.5H2O (2), respectively. The [Mo2O3S(HNTA)2]2− cluster units of 1 are interconnected by Na+ into a 3-D open framework with rutile topology templated by . The coordination of [Mo2O3S(HNTA)2]2− to the slightly smaller Dy3+ ion of greater ionic potential as a consequence of lanthanide contraction has been observed to form the pentanuclear heterometallic {Dy(H2O)6[Mo2O3S(HNTA)2]2}−, which is linked by Na+ and hydrogen bonds between the protonated carboxylate groups into a 3-D supramolecular framework. The weak antiferromagnetic interactions between the Dy3+ ions of 2 have been observed. 相似文献
138.
气相色谱-质谱法快速测定牛奶中的三聚氰胺和三聚氰酸 总被引:7,自引:1,他引:7
建立了气相色谱-质谱法测定牛奶中三聚氰胺和三聚氰酸含量的分析方法。样品经二乙胺-乙腈-水溶液超声提取,离心,滤液用氮气吹干后加入硅烷化衍生试剂衍生,气相色谱-质谱测定,选择离子模式监测,外标法定量。在0.025~2 mg/kg范围内,目标物的峰面积与其质量浓度的线性关系良好(r>0.98);在0.5,1.0和2.5 mg/kg的添加水平,三聚氰胺和三聚氰酸的平均回收率分别为84%~87%和75%~102%,相对标准偏差(RSD)分别为5.7%~11.7%和4.9%~7.8%;三聚氰胺和三聚氰酸的检出限(LOD)分别为0.05 mg/kg和0.10 mg/kg。结果表明:该方法简便、快速、灵敏、准确,适合牛奶中三聚氰胺和三聚氰酸的确证和定量测定。 相似文献
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140.
A new feruloyl amide derivative, named tribulusamide C, was isolated from the fruits of Tribulus terrestris. Its structure was determined on the basis of spectroscopic analysis including IR, 1-D-, 2-D-NMR and HR-ESI-MS. The structure of tribulusamide C was characterised by a unit of pyrrolidine-2,5-dione, which distinguished it from other lignanamides previously isolated from the fruits of T. terrestris. 相似文献