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Showing papers by "Sungkyunkwan University published in 1993"


Journal ArticleDOI
TL;DR: In this article, an idealized model of the charging process for stratified thermal storage tanks is developed, and the storage efficiency is analyzed in terms of the Peclet number.

56 citations


Journal ArticleDOI
30 Sep 1993-Gene
TL;DR: A considerable degree of sequence conservation and variation within rDNA gene clusters was revealed in this study, both at the infra- and suprageneric levels.

40 citations


Journal ArticleDOI
TL;DR: 3-oxo derivatives of natural 3-hydroxy triterpenes have been shown to have increased anti-HSV-1 activity in vitro, four to ten times as much as corresponding parent 3hydroxy compounds.
Abstract: 3-Oxo or/and 11-oxo derivatives of natural 3-hydroxy triterpenes,i.e., 3-oxoursolic acidIa, 11-oxoursolic acidIb, 3,11-dioxoursolic acidIc, 3-oxobetulinic acidIIa and 3-oxopomolic acidVIa were exhibited to show an increased anti-HSV-1 activityin vitro, four to ten times as much as corresponding parent 3-hydroxy compounds.

23 citations


Journal ArticleDOI
TL;DR: In this article, the authors examined the quantitative conversion of 26 acidic nonsteroidal anti-inflammatory drugs (NSAIDs) simultaneously to their corresponding tert. -butyldimethylsilyl (TBDMS) derivatives in a single step.

20 citations



Journal ArticleDOI
TL;DR: Based on the turbidimetric response of protein with 50%-trichloroacetic acid (TCA), the authors introduced an assay method for protein in solution, which can detect less amount than 10 μg/ml of bovine serum albumin.
Abstract: Based on the turbidimetric response of protein with 50%-trichloroacetic acid (TCA), this study aims to introduce an assay method for protein in solution. The standard procedure consists of mixing equal volume of sample solution (standard or unknown) with 50%-TCA solution and measuring the absorbance at 450 nm after 20 min. The absorbances of the solutions were almost stable over 120 min at room temperature. This assay method is simple, reproducible, and tolerant to many interfering substances. It can detect less amount than 10 μg/ml of bovine serum albumin. The assay method has low protein-to-protein variability over wide range of molecular weight.

10 citations


Journal ArticleDOI
TL;DR: In this paper, a magnetic microsphere system was adopted for tracing the microspheres injected and lodged in mice to confirm the biodegradability of biopolymers in vivo condition.
Abstract: To confirm a new evaluation technique for biodegradability of biopolymer microspheres in vivo condition, magnetic microsphere system was adopted for tracing the microspheres injected and lodged in mice. Microspheres of poly(DL-lactic acid), poly(L-lactic acid) and poly (DL-lactide-coglycolide)(PLGA) were prepared by solvent-extraction method and their organ distribution and biodegradation in mice was examined. Magnetic microspheres lodged in mice organs were recollected from the homogenates of mice organs with a constant flow magnetic separation apparatus. Recollected microspheres were observed by scanning electron microscopy and also were assayed for their magnetite content by atomic absorption spectrophotometry to evaluate the biodegradability of polymeric microspheres. This method seems to be practical and simple to estimate the biodegradability of biopolymers over the conventional methods.

7 citations


Proceedings ArticleDOI
16 Aug 1993
TL;DR: The proposed node architecture may contribute to greatly reducing communication latency through the interconnection network and show that parallel loops can be executed on this architecture more efficiently than on other competi tive ones.
Abstract: In most multithreaded node architectures moti? vated by the dataflow computational model, spatial parallelism could not be exploited at the thread level due to the resource deficit incurred by their inter nal organization. So we proposed a node architecture exploiting both spatial and temporal parallelism of a program. A multi-port non-blocking data cache is in corporated into our design to cope with the excessive data bandwidth required in parallel execution of mul tiple threads. The proposed node architecture may contribute to greatly reducing communication latency through the interconnection network. Simulation re sults show that parallel loops can be executed on this architecture more efficiently than on other competi tive ones.

6 citations


Journal ArticleDOI
TL;DR: Several naturally occurring furanocoumarins significantly inhibited microsomal lipid peroxidation not only mediated by endogeneous iron and NADPH but also initiated by CCl4 metabolites.
Abstract: Several naturally occurring furanocoumarins significantly inhibited microsomal lipid peroxidation not only mediated by endogeneous iron and NADPH but also initiated by CCl4 metabolites. Phellopterin, a potent inhibitor of cytochrome P-450, exhibited an almost complete inhibition of CCl4-induced hepatotoxicity as measured by sGPT activity 24 hr after CCl4 intoxication, whereas other furanocoumarins such as imperatorin, byakangelicin and oxypeucedanin methanolate exerted no protective effect. When compared with other cytochrome P-450 inhibitors (SKF-525A, AIA) and silymarin given at the same dose level (ED50), phellopterin still showed a significant inhibition of hepatotoxicity which was even stronger than that of AIA, known as a typical suicide inhibitor. Phellopterin was partially effective when given 30 min after CCl4 treatment. Repeated administrations of phellopterin, however resulted in a complete loss of the protection against CCl4-induced hepatotoxicity.

5 citations



Journal ArticleDOI
TL;DR: In this paper, the ambient anions, propargylic and allenic alcohols, may be equilibrated in solution, therefore in the condensation with aldehydes or ketones, two products can be formed.
Abstract: Regioselective synthesis of a-hydroxyallenes has great synthetic value, because they are used for the extention of carbon chain and the conversion of functionality (Patai, 1980; Okamura et al., 1982; Zweifel, 1983; Marshall, 1990; Cha., 1992; Mayers et al., 1993). Also, natural products such as antibiotics and pheromones have allenic linkage (Landor et al., 1971). Their utility in organic synthesis has been limited due to the difficulties in controlling the regioselectivity of the reactions. The ambient anions, propargylic and allenic anions, may be equilibrated in solution (Patai, 1978), therefore in the condensation with aldehydes or ketones, two products, propargylic and allenic alcohols, can be formed (Scheme 1).


Journal ArticleDOI
TL;DR: In this article, the surface segregation of sulfur in nickel doped with Ce, Hf and Mn was investigated by Auger electron spectroscopy, and the anodic polarization behavior of these alloys was examined to compare to that of pure nickel.
Abstract: It is known that sulfur segregates to grain boundaries even at low bulk concentration and embrittles nickel and nickel-based alloys or accelerates intergranular corrosion of this alloy. One way to reduce the sulfur segregation is to introduce strong sulfide forming elements into nickel such as, Ce, Cr, and Hf which can tie up sulfur in the nickel matrix. Another possible method would be to replace sulfur by segregating elements which help the cohesion of grain boundaries or improve grain boundary chemistry such as phosphorus or boron. Therefore, in this article, the authors investigated the surface segregation of sulfur in nickel doped with Ce, Hf and Mn by Auger electron spectroscopy, and the anodic polarization behavior of these alloys was examined to compare to that of pure nickel. Among the tested elements, Hf was found to be the most effective element in suppressing the sulfur surface segregation in nickel. However, Ni+470ppm Hf specimen showed pitting corrosion in 0.1 N H[sub 2]SO[sub 4] solution. All the elements (Mn, Ce, and Hf) added to nickel at the concentration of about 500ppm improved the ability to passivate the nickel but deteriorated the properties of the passive film. Ce addition into nickel might be themore » best choice among the examined elements to reduce the sulfur segregation in nickel-based alloys without deteriorating the corrosion characteristics.« less

Journal ArticleDOI
TL;DR: In this paper, the effects of SF6 and NF3 gas plasma treatments, and succesive rapid thermal anneal treatment for the recovery of modified silicon surface due to CHF3/C2F6 plasma have been investigated using X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS).
Abstract: The effects of SF6 and NF3 gas plasma treatments, and succesive rapid thermal anneal (RTA) treatment for the recovery of modified silicon surface due to CHF3/C2F6 plasma have been investigated using X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). XPS analyses have revealed that NF3 and SF6 plasma treatments are effective for the removal of residue layer. SIMS results show that penetrated impurities in the contaminated silicon substrate reduce through the additional RTA treatment. The effects of NF3, SF6 plasmas, and additional RTA treatments for the recovery of reactive ion etched silicon surface has been also studied by measuring the electrical performance of the silicon devices.