Chul Ung Kim

Structure of divergences in the Drell-Yan process with small transverse momentum

We consider the structure of divergences in Drell-Yan process with small transverse momentum. The factorization proof is not trivial because various kinds of divergences are intertwined in the collinear and soft parts at high orders. We prescribe a method to disentangle the divergences in the framework of the soft-collinear effective theory. The rapidity divergence is handled by introducing the

Factorization theorem for high-energy scattering near the end point.

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Selective Production of p-Xylene from Dimethylfuran and Ethylene Over Tungstated Zirconia Catalysts

regulator in the collinear Wilson lines. The collinear part, which consists of the transverse-momentum-dependent parton distribution function (TMDPDF), is free of the rapidity divergence after the soft zero-bin subtraction. There still remains the problem of mixing between the ultraviolet and infrared divergences, which forbids the renormalization group description. We show that the mixing is cancelled by the soft function. This suggests that the collinear and soft parts should be treated as a whole in constructing a consistent factorization theorem. The renormalization group behavior of the combined collinear and soft parts is presented explicitly at one loop. We also show that the integrated PDF can be obtained by integrating the TMDPDF over the transverse momentum.

Effect of cobalt catalyst type and reaction medium on Fischer-Tropsch synthesis

A consistent factorization theorem is presented in the framework of effective field theories. Conventional factorization suffers from infrared divergences in the soft and collinear parts. We present a factorization theorem in which the infrared divergences appear only in the parton distribution functions by carefully reorganizing collinear and soft parts. The central idea is extracting the soft contributions from the collinear part to avoid double counting. Combining it with the original soft part, an infrared-finite kernel is obtained. This factorization procedure can be applied to various high-energy scattering processes.

HIGH STRENGTH SAPO-34 MICROSPHERE CATALYST, METHOD FOR PREPARING SAME, AND METHOD FOR PREPARING LIGHT OLEFINS USING SAME

p-Xylene (PX) is an important large-volume commodity chemical in the petrochemical industry. Therefore, research on producing PX from bio-mass-derived resources is a considerable interest in relation to future alternative technologies. Recently, a new potential route for the direct and selective production of bio-based PX was reported, referred to as the Diels-Alder cycloaddition of biomassderived 2,5-dimethylfuran (DMF) and ethylene followed by the dehydration of an intermediate. Here, we prepared tungstated zirconia (WOx-ZrO2) materials at different calcination temperatures and times as solid acid catalysts for PX production. From structural analyses and measurements of the surface acidity, the WOx-ZrO2 was found to be composed of mesopores with high surface acidity within the optimum calcination temperature and time range. This WOx-ZrO2 catalyst exhibited high catalytic activity upon the cycloaddition of DMF with ethylene as compared to commercial beta zeolite and previously reported silica-alumina catalysts.