• Applied Chemistry for Engineering
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• v.1 no.2
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• pp.249-255
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• 1990

The conditions for separation and identification of anionic and nonionic surfactants by thin layer chromatography were investigated. Polyoxy alkylene-type nonionic surfactants were identified by the distribution of alkyl chain and alkylene oxide. Various polyoxyethylenated nonyl phenols were easily distinguished by densitometer. Some anionic surfactants were identified by $R_f$ and color, and the mixtures of anionic and nonionic surfactants were separated. Polyoxyethylenated fatty acid was separated into three parts of diester, monoester and polyethylene glycol, respectively, and the mixed ratio was determined by densitomer. All the experiments were carried out in 13-20 minutes, and the length of run was 80mm.

• Journal of the Korea Safety Management & Science
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• v.17 no.4
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• pp.381-396
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• 2015

The study proposes multiple TRIZ contradiction solution strategies for addressing PC (Physical Contradiction) and TC (Technical Contradiction) by implementing TRIZ cause-and-effect tree. The problem associated with TC of the ends is solved by PC of means which employs a causal relationship between causes and effects. The TRIZ contradiction solution strategies demonstrated in this research are classified into 3 types of combined strategy as follows: 1. To-Be PC and AS-Is PC, 2.To-Be PC and As-Is TC, 3.As-Is PC and To-Be TC. The combined strategy of To-Be PC and As-Is PC is similar to a divide-and-conquer technique. This strategy adopts parallel strategies using 4 separation principles in time, in space, between parts and the whole, and upon condition of two reversed-PCs. Moreover, its application elucidates the conflict relationship of two TCs from the study. The integrated 4 separation principles and 40 inventive principles present an effective synergy effect from the combination, and further addresses the problems in the TRIZ contradiction resolution strategies. Combined strategy of To-Be PC and As-Is TC implements the 40 inventive principles that To-Be PC of the means resolves the As-Is TC of the ends. Combined strategy of As-Is PC and To-Be TC also uses inventive principles to the As-Is PC of the means to solve the To-Be TC of the ends. In addition, propositional and logical relationship of necessary and sufficient conditions between TC and PC is used to support the validity of 3 TRIZ contradiction solution strategies. In addition, 3 other strategies of necessary and sufficient conditions validate the contraposition relationship of the truth table. This study discusses TRIZ case studies from National Quality Circle Contest from the years between 2011 and 2014 to provide the usage guidelines of TRIZ contradiction solutions for quality purposes. Examining analysis from the case studies and investigating combined strategies allows the users to obtain comprehensive understanding.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.2
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• pp.11-22
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• 2004

Conventional algorithms of separating overlapped objects are mostly based on template matching methods and thus their application domain is restricted to 2D objects and the processing time increases when the number of templates (object models) does. To solve these problems, this paper proposes a new approach of separating the occluding object from the stack of 3D objects using the relationship between surfaces without any information on the objects. The proposed algorithm considers an object as a combination of surfaces which are consisted with a set of boundary edges. Overlap of 3D objects appears as overlap of surfaces and thus as crossings of edges in 2D image. Based on this observation, the types of edge crossings are classified from which the types of overlap of 3D objects can be identified. The relationships between surfaces are represented by an attributed graph where the types of overlaps are represented by relation values. Using the relation values, the surfaces pertained to the same object are discerned and the overlapping object on the top of the stack can be separated. The performance of the proposed algorithm has been proved by the experiments using the overlapped images of 3D objects selected among the standard industrial parts.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.26-29
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• 2017

KARI has been conducting R&D for independent development of KSLV-II since 2010. Vehicle holding device is a device for vertically standing SLV on the launch pad of launch complex and fixing the lower part of vehicle in order to firmly fix vehicle so that SLV does not fall from an external load such as a wind load. When thrust generated after the 1st stage engine ignition of SLV must exceed the takeoff weight of vehicle, and holding device should be quickly released so that it does not interfere with takeoff of vehicle like other ground equipment at the beginning of the launch. Pyro-valve is one of the key components constituting VHD, and it should have high reliability and quick response characteristics with similar functional parts applied to launch vehicle separation device and satellite separation device. Through this paper, I intend to broaden the overall understanding of the development process of pyro-valve for VHD and KSLV-II.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.1
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• pp.70-77
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• 2008

Conventional PDP power system, which commonly uses two isolation transformer, consists of sustaining power ($V_S$), addressing power($V_A$), and Multi power($V_M$). Because each of these power conversion circuits use transformer and control IC, there are several defects: decrease of efficiency, rise of cost, and parts stress. This paper is proposed the method which operates PDP power system only with one transformer. The proposed method contributes not only to high-efficient performance of the DC/DC power stage and improvement of reliability but also to reduction of cost by reducing volume and size. Also, proposed method is proper to Address Display-period Separation(ADS) which is one of the driving methods of PDP. Superiority of the proposed method is proved by comparison with conventional method and theoretical, experimental analysis.

• Wind and Structures
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• v.35 no.1
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• pp.55-66
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• 2022

Tall buildings are often subjected to steady and unsteady forces due to external wind flows. Measurement and mitigation of these forces becomes critical to structural design in engineering applications. Over the last few decades, many approaches such as modification of the external geometry of structures have been investigated to mitigate wind-induced load. One such proven geometric modification involved the rounding of sharp corners. In this work, we systematically analyze the impact of rounded corner radii on the reducing the flow-induced loading on a square cylinder. We perform 3-Dimensional (3D) simulations for high Reynolds number flows (Re=1 × 105) which are more likely to be encountered in practical applications. An Improved Delayed Detached Eddy Simulation (IDDES) method capable of capturing flow accurately at large Reynolds numbers is employed in this study. The IDDES formulation uses a k-ω Shear Stress Transport (SST) model for near-wall modelling that prevents mesh-induced separation of the boundary layer. The effects of these corner modifications are analyzed in terms of the resulting variations in the mean and fluctuating components of the aerodynamic forces compared to a square cylinder with no geometric changes. Plots of the angular distribution of the mean and fluctuating coefficient of pressure along the square cylinder's surface illustrate the effects of corner modifications on the different parts of the cylinder. The windward corner's separation angle was observed to decrease with an increase in radius, resulting in a narrower and longer recirculation region. Furthermore, with an increase in radius, a reduction in the fluctuating lift, mean drag, and fluctuating drag coefficients has been observed.

• Natural Product Sciences
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• v.28 no.4
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• pp.168-180
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• 2022

Ephedra is a genus of the Ephedraceae family and is found in temperate regions, such as Central Asia and Europe. Among the various ephedra species, Ma Huang (Ephedra herb) is derived from the aerial parts of Ephedra sinica S tapf, Ephedra equisetina Bunge, and Ephedra intermedia Schrenk & C.A. Mey. Ma Huang contains various ephedra alkaloids, including (-)-ephedrine, (+)-pseudoephedrine, (-)-norephedrine, (+)-norpseudoephedrine, (-)-methylephedrine, and (+)-methylpseudoephedrine, which are found naturally as single enantiomers, although they can be prepared as racemates. Although the use of Ma Huang in foods is prohibited in Korea, products containing Ma Huang can be imported, and so it is necessary to develop a suitable analytical technique for the detection of Ma Huang in foods. Herein, we report the development of analytical methods for the detection of ephedra alkaloids in products containing Ma Huang. Following sample purification by solid phase extraction, quantitative analysis was performed using ultra-performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS/MS). Additionally, the enantiomers were successfully separated using HPLC-DAD. We successfully analyzed various food samples, where the ephedra alkaloids were qualitatively and quantitatively determined, and the enantiomers were separated. It is expected that these methods may contribute toward preventing the distribution of illegal products containing Ma Huang.

• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1935-1945
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• 2023

The radiological safety of workers in a newly developed microwave-based spent resin treatment facility was assessed based on work location and operational scenarios. The results show that the remote-operation room worker was exposed to maximum annual dose of 3.19E+00 mSv, which is 15.9% of the dose limit, thereby confirming radiological safety. Inside the pathway, annual doses in the range of 7.87E-02-2.07E-01 mSv were measured initially at the mock-up tank and later at the point between the spent resin separation and treatment parts. The dose of emergency maintenance workers was below the dose limit (4.08E-03-4.99E+00 mSv); however, before treatment (separation and microwave), the dose of maintenance and repair workers exceeded the dose limit. The doses of the effluent removal workers at the zeolite and activated carbon storage tank and spent resin storage tank were the lowest at 2.79E-01-2.87E-01 mSv and 9.27E-01 mSv in "1 h" and "4-5 h of operation", respectively. The immediately lower and upper layers of the facility room exhibited the highest annual doses of 1.84E+00 and 3.22E+00 mSv, respectively. Through this study, a scenario that can minimize the dose considering the movement of spent resin through the facility can be developed.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.2
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• pp.165-171
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• 2003

Sixty semen ejaculates collected at weekly interval from four Murrah Buffalo bulls over a period of seven months (Nov.1999 to May 2000) were used in the present study. Three buffer medium (sodium citrate, TES and Tris) were used for soaking of sephadex. Three grades of sephadex (G-15,G-100, and G-200) were used for preparation of columns. Columns of three different height (one, two and three cm) were used for separation of semen. Twenty semen ejaculates were used in each project. In the first experiment each semen ejaculates was divided into four parts. One part was kept as control and other three parts were passed thought one cm column of sephadex G-15 prepared in three different buffers. There was significant (p<0.05) increase in percent progressive sperm motility and percent live spermatozoa and decrease in percent abnormal spermatozoa and percent spermatozoa with damaged acrosome as well as sperm numbers after filtration through all the three columns. Sperm quality obtained in the filtrate of column prepared in Tris buffer was better in comparison to other two buffers. So the Tris buffer was used in the second trial. Twenty semen ejaculates were used in this experiment. Each semen ejaculate was divided into four parts. One part was kept as control (non-filtered) and other three parts were passed through columns of different grade of sephadex (G-15, G-100 and G-200). Progressive sperm motility and live sperm percentage improved significantly while decline in percent abnormal spermatozoa and percent spermatozoa with damaged acrosome and sperm concentration was observed after filtration through all the columns as compared to control (non-filtered) semen. Since post filtration quality of semen was better in the sephadex G-100 column, therefore it was selected for the next experiment. In third experiment, Tris buffer and sephadex G-100 were used for preparing columns of different height (one, two and three cm) and twenty semen ejaculates were filtered. The quality characteristics of semen (percent progressive sperm motility, percent live spermatozoa and sperm concentration) after filtration through one cm column were significantly (p<0.05) higher than after filtration through columns of two and three cm height. However non -significant (p>0.05) difference due to height of columns was observed for percent abnormal and percent damaged acrosome but 1 cm column comparatively gave better result than of 2 and 3 cm column height.

• Journal of the Korean Society of Costume
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• v.52 no.5
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• pp.61-77
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• 2002

The purpose of this study is to investigate difference and likeness on the form in women's Hanbok between the later Chosun Dynasty and modern times based on Belong's observing system for 'Apparel-Body Construct'. Belong's framework is composed 5 pairs of contrast word -'Closed or Open', 'Whole or Par', 'Planar Separation or Planar integration'. 'Flat or Rounded', and 'Determinate or Indeterminate'. Major findings of this study are as follows. First, the form of women's Hanbok in later Chosun Dynasty is 'Variably Closed', 'Part' and 'Rounded', whereas that in modern is 'Open', 'Whole' and 'Flat' Women's Hanbok of modern is lesser convex, and more open than that of later Chosun Dynasty according to increasing use of transparent textiles. Moreover, in comparison with old style, that of modern has the tendency of perceiving primarily whole feature by organic linkage of parts. Because of loose fit of Jeogori and rigid DongJong etc, characteristic of 'Plat' strengthened in modern Hanbok. Secondly, women's Hanbok in the later Chosun Dynasty and modern has common properties of 'Planar Seperation' and 'Determinate'. Women's Hanbok belongs to 'Planar Seperation', because the effect cognized to figure and ground. can be found between small parts and whole of Jegori, or can be found between the head and face. Jeuori and waist band, and Chima and under ware. Further more. it can be classified into 'Determinate'. because it use textiles which have no pattern un it or which show a subtle surface effect by texture changing.