• Economic and Environmental Geology
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• v.19 no.3
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• pp.199-218
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• 1986

Arsenopyrite in arsenic and polymetallic ores from calcic Fe-W skarn deposit of the Ulsan mine, Republic of Korea, has been investigated by means of electron microprobe analysis and X-ray diffractometry. As a result, it is revealed that the Ulsan arsenopyrite may be classified into the following three species with different generation on the basis of its mode of occurrence, chronological order during polymetallic mineralization and chemical composition; arsenopyrites I, II and III. 1) Arsenopyrite I-(Ni, Co)-bearing species belonging to the oldest generation, which has crystallized together with (Ni, Co)-arsenides and -sulpharsenides in the early stage of polymetallic mineralization. In rare cases, it contains a negligible amount of antimony. It occurs usually as discrete grains with irregular outline, showing rarely subhedral form, and is diffused in skarn zone. The maximum contents of nickel and cobalt are 10.04 Ni and 2.45 Co (in weight percent). Occasionally, it shows compositional zoning with narrow rim of lower (Ni+Co) content. 2) Arsenopyrite II-arsenian species, in which (Ni+Co) content is almost negligible, may occur widely in arsenic ores, and its crystallization has followed that of arsenopyrite I. It usually shows subhedral to euhedral form and is closely associated with $l{\ddot{o}}llingite$, bismuth, bismuthinite, chalcopyrite, sphalerite, bismuthian tennantite, etc. It is worthy of note that arsenopyrite II occasionally contains particles consisting of both bismuth and bismuthinite. 3) Arsenopyrite III-(Ni, Co)-free, S-excess and As-deficient species is close to the stoichiometric composition, FeAsS. It occurs in late hydrothermal veins, which cut clearly the Fe-W ore pipe and the surrounding skarn zone. It shows euhedral to subhedral form, being extremely coarse-grained, and is closely associated with pyrite, "primary" monoclinic pyrrhotite, galena, sphalerite, etc. Among three species of the Ulsan arsenopyrite, arsenopyrite I does not serve as a geothermometer, because (Ni+Co) content always exceeds 1 weight percent. In spite of the absence of Fe-S minerals as sulphur-buffer assemblage, the presence of $Bi(l)-Bi_2S_3$ sulphur-buffer enables arsenopyrite II to apply successfully to the estimation of either temperature and sulphur fugacity, the results are, $T=460{\sim}470^{\circ}C$, and log $f(S_2)=-7.4{\sim}7.0$. With reference to arsenopyrite III, only arsenopyrite coexisting with pyrite and "primary" monoclinic pyrrhotite may serve to restrict the range of both temperature and sulphur fugacity, $T=320{\sim}440^{\circ}C$, log $f(S_2)=-9.0{\sim}7.0$. These temperature data are consistent with those obtained by fluid inclusion geothermometry on late grandite garnet somewhat earlier than arsenopyrite II. At the beginning of this paper, the geological environments of the ore formation at Ulsan are considered from regional and local geologic settings, and physicochemical conditions are suspected, in particular the formation pressure (lithostatic pressure) is assumed to be 0.5kb (50MPa). The present study on arsenopyrite geothermometry, however, does not bring about any contradictions against the above premises. Thus, the following genetical view on the Ulsan ore deposit previously advocated by two of the present authors (Choi and Imai) becomes more evident; the ore deposit was formed at shallow depth and relatively high-temperature with steep geothermal gradient-xenothermal conditions.

• Korean Journal of Food Science and Technology
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• v.39 no.4
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• pp.372-379
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• 2007

A high-performance liquid chromatography-electrospray ionization (HPLC-ESI) tandem MS was developed for the rapid and simultaneous determination of forbidden medicines in dietary supplements. Thirteen medicinal components such as PDE-5 inhibitors and their analogues, and the newly identified dimethylsildenafil and xanthoanthrafil, were included in this study. After tentative standardization of molecular ions in both polarities using thirteen references on the mass spectrometer, with ESI-continuous infusion via the syringe pump method, the relative intensity of the ions present in the resulting spectra was quantitatively compared. From the results, the ion mode was selected depending on each reference's characteristics. A HPLC method coupled with the ESI mode was developed considering the matrix effect and interference depending on the type of sample. The validation test of the developed method was followed by carrying out precision, accuracy, recovery, sensitivity and linearity, etc. The method showed sufficiently high sensitivity, reproducibility, and specificity, and produced 4 times faster results when compared with the existing HPLC/UV method for the determination of forbidden compounds in dietary supplements.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.3
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• pp.251-260
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• 1998

It is well known that the clinical test for responsibility of accurate fertilization capacity in male partners is very important to diagnose and treat the infertility. However, it has been reported that the traditional semen analysis cannot accurately predict fertilization and pregnancy potential. The present study was performed to evaluate the acrosomal reaction to ionophore challenge (ARIC) test as a prognostic indicator for fertilization of sperm and oocyte in an in vitro fertilization and embryo transfer (IVF-ET) program. From March 1996 to Februry 1997, 30 couples undergoing IVF program were allocated to this study group. All female partners in the study group were 35 years old or less and their serum level of basal follicle stimulating hormone (FSH) and estradiol $(E_2)$ were normal. All the male partners have normal parameters of semen analysis. The ARIC tests were performed on the day of ovum pick up and in vitro insemination in all the male partners. The controlled ovarian hyperstimulation (COH) using luteal long protocol of gonadotropin releasing hormone (GnRH) agonist was used in all couples for IVF-ET. The acrosomal reaction with $10{\mu}l$ of 10% DMSO was induced spontaneously in $10.1{\pm}9.8%$, and acrosomal reaction with calcium ionophore A 23187 was induced in $27.4{\pm}18.1%$, and the ARIC value was $17.4{\pm}16.2%$. There were no significant correlation between the ARIC value and the fertilization rate ($r^2$=0.044, p=0.268). There were also no significant correlation between the ARIC value and the percentage of the grade I, II embryos ($r^2$=0.046, p=0.261). On the basis of above results, it was suggested that ARIC test might not be a useful prognostic indicator for fertilization in IVF-ET in male partners with normal parameters of conventional semen analysis. We guessed that IVF-ET could be performed to the patients primarily without universal appilcation of ARIC test to all male partenrs, and if fertilization failure occurs, the micro assisted fertilization (MAF) such as intracytoplsmic sperm injection (ICSI) might be used as an alternative mode of treatment with acceptable success rate.

• KSBB Journal
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• v.10 no.3
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• pp.304-316
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• 1995

For fuel alcohol production, enzymatic liquefaction and saccharification of tapioca starch by ${\alpha}$-amylase and glucoamylase were studied. The thermophilic ${\alpha}$-amylase Termamyl produced from Bacillus licheniformis gave a better liquefaction than the relalively low temperature enzyme BAN from B. subtilis. Oplimal temperature and pH with Termamyl were $90∼95^{\circ}C$ and 5.8, respectively. Minimal amount of Termamyl 240uc for a satisfactory liquefaction for a two-hour reaction was about 0.0125% (v/w) with respect to the mass of tapioca used. For saccharification experiments two enzymes, Novo AMG and Do-I1 enzymes were compared. The enzymatic activity of each enzyme was a little different depending on the substrate used and the latter was found to have a significant amount of ${\alpha}$-amylase activity. With Novo AMG optimal temperature was about $58^{\circ}C$ The pH optimum was 4.3 with maltose, however, with tapioca, no difference was observed between pH 4.3 and 5.7 which is a natural, unadjusted pH of liquefied tapioca. For 85% of completion of saccharification, it was necessary to use 0.0625% (v/w) of Novo AMG 400L for tapioca and to run the reaction for more than 10 hr, Packed volume of solid particles in tapioca slurry remained at around 30% during liquefaction and saccharification. This indicates that the removal of the solid particle before fermentation is not economically feasible at all, even though the solid particles make it very difficult to operate the bioreactor in a continuous mode with cell-recycle.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.213-219
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• 2003

As the 2-D hydraulic experimental results for the submerged rubble-mound structure, we have concerned with their stability/function characteristics of structures by the effects of wave force, scour/deposition at the toe and wave transmission ratio at the lee-side sea. And as to investigate the variation characteristics of wave transmission ratio which depended to a geometrical structure of the submerged breakwater profiles, the critical conditions for the depth of submergence and crest width obviously presented. In summary, there results lead us to the conclusions that the wave control capabilities of submerged breakwaters by the variation of the submergence depth is high about 4 time degrees at the efficiency than the that of crest width. The destruction of covering block at the crest generated at the region which located between maximum damage curve, it maximum damage/failure station from the toe of the structure were 0.2L. As the wave transmission coefficient and the slope of the structure increase, the damage/failure ratio and the maximum scour depth at the toe was extended, respectively. When maximum scour depth happened. The destruction of covering block which located at the toe generated at the front slope destruction. Finally, it was found from the results that the optimization of structure may be obtained by the efficiently decision of the submergence depth and crest width in the permissible range of wave transmission ratio.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.5
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• pp.528-534
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• 2003

The 2-D hydraulic experimental results for the submerged rubble-mound structure, we have been concerned with the slability/function characteristics of the structures by the effects of wave force, scour/deposition at the toe and the wave transmission ratio at the lee-side sea. So, to investigate the variation characteristics of the wave transmission ratio which depended on a geometrical structure of the submerged breakwater profiles, the critical conditions for the depth of submergence and crest width were obviously presented. In summary, the results lead us to the conclusion that the wave control capabilities of submerged breakwaters by the variation of the submergence depth is higher than about 4 times the degree at the efficiency than the that of crest width. The destruction of the covering block at the crest generated at the region which was located between the maximum and minimum damage curve, and it's maximum damage/failure station from the toe of the structure was $0.2\;L_s.$ As the wave transmission coefficient and the slope of the structure increase, the damage/failure ratio and the maximum scour depth at the toe was extended, respectively. When the maximum scour depth happened, the destruction of the covering block which was located at the toe generated at the front of the submerged rubble-mound breakwater. Finally, it was found from the results that the optimization of the structure may be obtained by the efficient decision of the submergence depth and crest width in the permissible range of the wave transmission ratio.

• Journal of the Korean Society of Tobacco Science
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• v.29 no.2
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• pp.140-145
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• 2007

Acrylamide has been found in many foods. Acrylamide in foodstuffs were analyzed by a GC/MS after bromination of acrylamide or by a LC/MS for underivatized acylamide. Time consuming and laborious clean up procedures is applied for the purification of the extract, in these methods. In this study, a simple and fast method without clean up step for the analysis of acrylamide in mainstream cigarette smoke was developed by using liquid chromatography-tandem mass spectrometry (LC/MS/MS) and the effects of tobacco leaf constituents on acrylamide content was observed. The analysis of acrylamide in mainstream cigarette smoke started to collect TPM (total particulate matter) from smoking and to extract by 0.1 % acetic acid solution and then to detect by liquid chromatography tandem mass spectrometry using electrospray in the positive mode. The recovery of acrylamide in 2R4F reference cigarette was 98 % and the reproducibility was 2.5 % and the limit of detection was 1.6 ng/mL. Reducing sugars and amino acids are considered to be main precursors of acrylamide in foodstuffs. Cut tobacco contain substantial amounts of reducing sugars and amino acid which may be explained the occurrence of acrylamide in mainstream cigarette smoke. The effects of reducing sugars and total nitrogen studied in an experiment with a various tobacco types. This result indicated that reducing sugars are not limiting factor for acrylamide formation, but the level of acrylamide in cigarette smoke was significantly correlated with the total nitrogen contents.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.103.1-103.1
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• 2011

Recent observations by Hinode show weakly-attenuated coronal loop oscillations in the presence of background flow (Ofman & Wang 2008, A&A, 482, L9). We study the vertical kink oscillations in solar coronal loops, considering field aligned flows inside the loops as well as surrounding the loops environment. The two dimensional numerical model of straight slab is used to explore the excitation and attenuation of the impulsively triggered fast magnetosonic standing kink waves. A full set of time dependent ideal magnetohydrodynamics equations is solved numerically taking into account the value of flow of the order of observed flows detected by SOT/Hinode. We find that relaxing the assumption of the limited flows within the loops enhances the damping rate of the fundamental mode of the standing kink waves by 2 - 3 % as compared to flow pattern which is basically localized within the loops. We further notice that extending the flow pattern beyond the loop thickness also enhances the strength of the shock associated with slow magnetoacoustic waves, recognized as an addition feature detected in the numerical simulation. The wider out-flow pattern destroys the oscillation patterns early as compared to narrower flow pattern, in other words we can say that it affects the durability of the oscillation. However, for the typical coronal loops parameters we find that the observed durability periods of the SOT/Hinode observation can be achieved with an out-flow Gaussian patterns for which half-width is not greater than factor 2.0 of the loop-half-width. explain a possible relation between electric current structure and sigmoid observed in a preflare phase.

• Land and Housing Review
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• v.11 no.2
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• pp.33-46
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• 2020

As the fastest growing office transaction volume in Korea, there's been a need for development of indicators to accurately diagnose the office capital market. The purpose of this paper is experimentally calculate to the office price index for effective benchmark indices in Seoul. The quantitative methodology used a Case-Shiller Repeat Sales Model (1991), based on actual multiple office transaction dataset with over minimum 1,653 ㎡ from Q3 1999 to 4Q 2019 in the case of 1,536 buildings within Seoul Metropolitan. In addition, the collected historical data and spatial statistical analysis tools were treated with the SAS 9.4 and ArcGIS 10.7 programs. The main empirical results of research are briefly summarized as follows; First, Seoul office price index was estimated to be 344.3 point (2001.1Q=100.0P) at the end of 2019, and has more than tripled over the past two decades. it means that the sales price of office per 3.3 ㎡ has consistently risen more than 12% every year since 2000, which is far above the indices for apartment housing index, announced by the MOLIT (2009). Second, between quarterly and annual office price index for the two-step estimation of the MIT Real Estate Research Center (MIT/CRE), T, L, AL variables have statistically significant coefficient (Beta) all of the mode l (p<0.01). Third, it was possible to produce a more stable office price index against the basic index by using the Moore-Penrose's pseoudo inverse technique at low transaction frequency. Fourth, as an lagging indicators, the office price index is closely related to key macroeconomic indicators, such as GDP(+), KOSPI(+), interest rates (5-year KTB, -). This facts indicate that long-term office investment tends to outperform other financial assets owing to high return and low risk pattern. In conclusion, these findings are practically meaningful to presenting an new office price index that increases accuracy and then attempting to preliminary applications for the case of Seoul. Moreover, it can provide sincerely useful benchmark about investing an office and predicting changes of the sales price among market participants (e.g. policy maker, investor, landlord, tenant, user) in the future.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.68.1-68.1
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• 2014

We present the results of far-ultraviolet (FUV) observations of comet C/2001 Q4 (NEAT) obtained with Far-ultraviolet Imaging Spectrograph (FIMS) on board the Korean microsatellite STSAT-1, which operated at an altitude of 700 km in a sun-synchronous orbit. FIMS is a dual channel imaging spectrograph (S-channel 900-1150 ${\AA}$, L-channel 1350-1710 ${\AA}$, and ${\lambda}/{\Delta}{\lambda}$ ~ 550 for both channels) with large image fields of view (S-channel $4.0^{\circ}{\times}4.6^{\prime}$, L-channel $7.5^{\circ}{\times}4.3^{\prime}$, and angular resolution ~ $5-10^{\prime}$) optimized for the observation of diffuse emission of astrophysical radiation. Comet C/2001 Q4 (NEAT) were made in two campaigns during its perihelion approach between May 8 and 15, 2004. Based on the scanning mode observations in the wavelength band of 1400-1700 ${\AA}$, we have constructed an image of the comet with an angular size of $5^{\circ}{\times}5^{\circ}$, which corresponds to the central coma region. Several important fluorescence emission lines were detected including S I multiplets at 1429 and 1479 ${\AA}$, C I multiplets at 1561 and 1657 ${\AA}$, and the CO $A^1{\Pi}-X^1{\Sigma}^+$ Fourth Positive system; we have estimated the production rates of the corresponding species from the fluxes of these emission lines. The estimated production rate of CO was $Q_{CO}=(2.65{\pm}0.63){\times}10^{28}s^{-1}$, which is 6.2-7.4% of the water production rate and is consistent with earlier predictions. The average carbon production rate was estimated to be $Q_C={\sim}1.59{\times}10^{28}s^{-1}$, which is ~60% of the CO production rate. However, the observed carbon profile was steeper than that predicted using the two-component Haser model in the inner coma region, while it was consistent with the model in the outer region. The average sulfur production rate was $Q_S=(4.03{\pm}1.03){\times}10^{27}s^{-1}$, which corresponds to ~1% of the water production rate.