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11.
We study the medium modified fragmentation function in high-energy heavy-ion collisions. We show that the ACSX and QW formalisms are equivalent to each other in the high-Q2 limit in both theoretical and numerical aspects. 相似文献
12.
Peter Albers Monika Maier Martin Reisinger Bernd Hannebauer Rudolf Weinand 《Crystal Research and Technology》2015,50(11):846-865
The structural properties of finely divided inorganic materials such as metal and metalloid oxides, silicates or carbonates of both synthetic and natural origin are compared by means of electron microscopy and tomography. The structure of the outer surfaces of various compact or compacted agglomerates may suggest some striking similarities between various amorphous silica on the one hand and crystalline titania and alumina on the other however the details of the interior fine structure are completely different. Inside of the crystalline aggregates of, for example, alumina and titania distinct grain boundaries between the inter‐grown primary crystallites exist. Also physical boundaries between different solid phases and crystalline/amorphous transitions in core/shell structures can occur. No physical grain or phase boundaries were found inside of synthetic amorphous silica or para‐crystalline carbon black thus, the aggregate is the constituent particle. Synthetic amorphous silica from different production technologies (fumed/pyrogenic, precipitated, aerogel, gel) may exhibit different macro‐morphology but distinct similarities of the amorphous silica networks. Computational studies on silica and titania underline the stability of constituent particles and aggregates as observed by means of TEM after dispersing the original materials by ultra‐sonication. 相似文献
13.
Fluctuations of dilepton production from two photon interactions γγ→l~+l~- are studied in semicentral and peripheral nuclear collisions.Based on the Weizsacker-Williams approach,electromagnetic(EM) fields generated by moving nuclear charges are approximated as quasi-real photons.As fluctuating EM fields in each collision event are hard to be measured directly in experiments due to its short lifetime,we study the dilepton photoproduction with fluctuating EM fields,which are crucial for the EM fields induced chiral and charged particle evolutions,and calculate the relative standard deviation of the dilepton mass spectrum with the event-by-event fluctuating nuclear charge distributions.This fluctuation effect becomes smaller in more peripheral collisions where the shift of proton positions is implicit for EM fields outside the nucleus.The uncertainty of effective impact parameter △b on the standard deviation is also studied,and its effect is around one-third of the effect of nuclear charge fluctuations when △b is taken as~1 fm. 相似文献
14.
The three lowest-lying states, i.e., (1S), (2S), and (3S), composed of bb¯ pairs and below the BB ¯ threshold, provide a good platform for the researches of hadronic physics and physics beyond the Standard Model. They can be produced directly in e+e− colliding experiments, such as CLEO, Babar, and Belle, with low continuum backgrounds. In these experiments, many measurements of the exclusive (1S) and (2S) decays into light hadrons, which shed light on the “80% rule” for the Okubo–Zweig–Iizuka suppressed decays in the bottomonium sector, were carried out. Meanwhile, many studies of the charmonium and bottomonium productions in (1S, 2S, 3S) decays were performed, to distinguish different Quantum Chromodynamics (QCD) models. Besides, exotic states and new physics were also extensively explored in (1S, 2S, 3S) decays at CLEO, BaBar, and Belle. The (1S, 2S, 3S) states can also be produced in pp collisions and in collisions involving heavy ions. The precision measurements of their cross sections and polarizations at the large hadron collider (LHC), especially in the CMS, ATLAS, and LHCb experiments, help to understandΥproduction mechanisms in pp collisions. The observation of the sequentialΥsuppression in heavy ion collisions at CMS, LHCb, and ALICE is of great importance for verifying the quark–gluon plasma predicted by QCD. In this article, we review the experimental results on (1S, 2S, 3S) at e+e− colliders and the LHC, and summarize their prospects at Belle II and the LHC. 相似文献
15.
利用柱层析法(硅胶,C18)从日香桂根的乙酸乙酯提取物中分离出8个单体化合物[女贞苷(1),连翘苷(2),(+)-羟基松脂醇-1-O-β-D-葡萄糖(3),(+) 环橄榄树脂素(4), 2α,3β-二羟基乌苏-12-烯-28酸(5),对羟基苯乙醇(6),(-) 橄榄脂素(7)和橄榄树脂素-4-O-β-D-葡萄糖苷(8)],其结构经1H NMR和13C NMR确证。5为首次在木犀科植物中发现,4为首次在木犀属植物中发现,2, 3, 7和8为首次在日香桂植物中发现。 相似文献
16.
金属配合物在天然药物研究及分析中的应用进展 总被引:7,自引:0,他引:7
评述了天然药物中有效成分的金属配合物在新药开发,天然药物中有效成分定量分析的应用进展,引用文献68篇。 相似文献
17.
首次通过ICP-AES仪研究了分子筛化学组成全分析的方法,采用HNO3-HF混合酸密闭溶样,用H3BO3配合F^-,分别采用内标法和基体消除法消除基体效应.将研究结果与经典方法比较表明:采用本文研究的分析方法,结果准确可靠,符合分析要求,尤其对杂原子分子筛以及金属氧化物修饰的分子筛的组成分析具有应用价值. 相似文献
18.
Using quantum mechanics GASTEP software package based on the first principle density function theory, the electronic structure and optical properties of Ga1−xAlxAs at different Al constituent are calculated. Result shows that with the increase of Al constituent, the band gap of Ga1−xAlxAs increases and varies from direct band gap to indirect band gap; the absorption band edge and the absorption peak move to high-energy side; the static reflectivity decreases. With the increasing of the incident photon energy, Ga1−xAlxAs shows metal reflective properties in certain energy range. With the increasing of Al constituent, static dielectric constant decreases and the intersection of dielectric function and the x-axis move towards high-energy side; the peak of energy loss function move to low-energy side and the peak value reduces. 相似文献
19.
将在动量空间具有积分形式的单胶子交换梯形近似下Bethe-Salpeter方程化为微分方程,求出该方程在四动量为零时的赝标解全部分量,其中第一分量为已知的Goldstein解. 相似文献
20.
V.?Yu.?Grishina L.?A.?Kondratyuk W.?CassingEmail author M.?Mirazita P.?Rossi 《The European Physical Journal A - Hadrons and Nuclei》2005,25(1):141-150
Using the Quark-Gluon Strings Model --combined with Regge phenomenology-- we perform a comparative analysis of Λ, Σ0, Λ(1520) and Θ+ production in binary reactions induced by photon, pion and proton beams on the nucleon. We find that the existing experimental data on the γp↦K+Λ differential and total cross-sections can be described very well by the model for photon energies 1-16 GeV and - t < 2 GeV2 assuming a dominant contribution of the K* Regge trajectory. Moreover, using the same parameters we also reproduce the total γp↦K+Σ0 and γp↦K+Λ(1520) cross-sections suggesting a “universality” of the Regge model. In order to check the consistency of the approach we evaluate the differential and total cross-sections for the reaction π-p↦K0Λ which is also found to be dominated by the K* Regge trajectory. Using the apparent “universality” of the Regge model we extend our scheme to the analysis of the binary reactions γp↦¯0Θ+, π-p↦K-Θ+ and pp↦Σ+Θ+ as well as the exclusive and inclusive Θ+ production in the reactions pp↦p¯0Θ+ and pp↦Θ+X. Our detailed studies demonstrate that Θ+ production does not follow the “universality” principle, thus suggesting an essentially different internal structure of the exotic baryon relative to conventional hyperons or hyperon resonances. 相似文献