Abstract: A portable computer includes a computer main body, and a display part connected to the computer main body and having a display panel to display an image thereon, a plurality of coupling parts which are formed on opposite side walls of the display panel, a support bracket which supports the opposite side walls of the display panel and varies in length, and having a pair of supporters slidably coupled to each other, and a coupling member which is coupled to one of the plurality of coupling parts to couple the support bracket to the display panel. Thus, the portable computer having the support bracket which varies in length according to a size of a display panel is used for display panels of various sizes.

Abstract: Disclosed is a method for removing sludge in a crude oil storage tank by use of thermal oil discharged from a distillation tower of an oil refinery, such as atmospheric residue, vacuum residue, or vacuum gas oil, and recovering oil having various applications by separating inorganics therefrom. The method is advantageous in terms of minimizing air pollution because of utilizing a closed system, drastically reduced washing time of crude oil storage tank, and continuous removal of the sludge. Additionally, the recovered oil can be provided as fuel oil, marine oil or a feed for secondary treatment processes, such as up-grading processes of heavy oil.

Abstract: Disclosed is a method for removing sludge in a crude oil storage tank by use of thermal oil discharged from a distillation tower of an oil refinery, such as atmospheric residue, vacuum residue, or vacuum gas oil, and recovering oil having various applications by separating inorganics therefrom. The method is advantageous in terms of minimizing air pollution because of utilizing a closed system, drastically reduced washing time of crude oil storage tank, and continuous removal of the sludge. Additionally, the recovered oil can be provided as fuel oil, marine oil or a feed for secondary treatment processes, such as up-grading processes of heavy oil.

Abstract: Disclosed is a method for preparing DL-&agr;-tocopherol through the condensation of isophytol or phytol derivatives and trimethylhydroquinone (TMHQ) using a catalyst system comprising a divalent metal halogen compound, silica gel and/or silica-alumina, and a Brönsted acid. Isophytol or phytol derivatives are slowly added to trimethylhydroquinone for the condensation thereof at 80 to 135° C. over 30 to 60 min in the presence of the metal halogen and the silica gel and/or silica-alumina. In the presence of the Brönsted acid, the intermediates are converted into the product. The silica gel and/or silica-alumina is washed with a polar solvent for recovery. The catalyst system can remarkably reduce side-reactions upon the condensation of isophytol or phytol derivatives and TMHQ, thus producing DL-&agr;-tocopherol with a high purity at a high yield.