• Journal of the Korean Ceramic Society
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• v.34 no.1
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• pp.70-78
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• 1997

3Y-TZP/SUS316 Functionally Graded Material (FGM) was fabricated by slip casting method. Alumina mold was used to overcome problems of gypsum mold in slip casting process, and the optimal dispersion con-ditions of 3Y-TZP/SUS316 binary slurries was determined using electrokinetic sonic amplitude and a viscometer, and observing sedimentation behavior. The properties of the specimens casted by gypsum mold and alumina mold were compared in terms of changes in shrinkage rate, drying and sintering conditions, and microstructure. It was found that the specimens obtaine from the alumina mold showed a clean surface, easier thickness control of each layer, and higher productivity. Especially, no degradation was observed in the SUS316 prepared using alumina mold. Thus it is desirable to use porous alumina mold rather than gyp-sum mold for the slip casting of 3Y-TZP/SUS316-FGM.

• Analytical Science and Technology
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• v.34 no.3
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• pp.115-121
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• 2021

Ethyl glucuronide (EtG) and ethyl sulfate (EtS), which are ethanol metabolites, are direct indicators of ethanol intake; they have been studied in a variety of biological samples in forensic science. It is necessary to analyze ethanol metabolites to determine whether the ethanol detected in autopsy cases was due to alcohol consumption before death or due to the ethanol produced from post-mortem decay. In general, EtG and EtS are detected in the blood together with ethanol; however, it may be difficult to secure blood depending on the extent of decay. Therefore, the aforementioned method should be replaced by detecting the ethanol metabolites using tissue biological samples. In this study, we determined the optimal experimental conditions for detecting EtG and EtS from spleen samples using Liquid Chromatography - Tandem Mass Spectrometry (LC-MS/MS). Herein, the test method was validated, and an analysis method was applied to the actual autopsy cases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1373-1380
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• 2010

The plate loading test(PLT) and the field density test are mainly used on the construction of embankments to control the compaction of a limited layer thickness. These two test methods are very time consuming and inefficient, but they are still commonly used as the methods of quality control for soil compaction. In the last 3 decades, many devices such as geogauge, light falling weight deflectometer(LFWD) and dynamic cone penetrometer(DCP) etc., have been introduced into the engineering market with the objective of acquiring in situ stiffness properties of the compacted soil layers. Recently, a new type of sensor, called compactometer, which in mounted on the drum of a roller and measures impact forces continuously with GPS, called as Continuous Compaction Control(CCC), has come into use in many countries such as America, Germany, Japan and so on. The main objective of this paper is to assess the potential use of these new devices as quality control and assurance devices for compacted soil layers. Based on this study, compactometer and the LFWD results werestrongly correlated with the result obtained from the PLT and the field density test.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.4
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• pp.297-304
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• 2021

In this study, we prepared a pigmented skin model, KeraSkin-M^TM for the in vitro evaluation of whitening agents. For the purpose of complementing the existing mono-layer cell culture testing method, KeraSkin-M^TM was produced through the co-culture of human skin-derived keratinocytes and melanocytes. The efficacy of four well-known whitening agents (arbutin, ascorbic acid, kojic acid, niacinamide) was evaluated in KeraSkin-M^TM in order to assess its usefulness in assessing whitening efficacy. As a result, it was possible to observe additional details such as the distribution of melanin granules and melanin capping in each skin layer through KeraSkin-M^TM, which was previously difficult to assess in the traditional 2D cell culture system. In addition, quantification through image analysis of KeraSkin-M^TM allowed for a statistical analysis of the whitening effects. These results suggest that the KeraSkin-M^TM can be used as a new evaluation method of evaluating whitening efficacy, as well as complement the traditional total melanin content and tyrosinase inhibition assays.

• YAKHAK HOEJI
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• v.54 no.2
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• pp.142-149
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• 2010

Development of alternative testing methods for the replacement of hazardous reagents with less hazardous ones is strongly enforced because exposure of human and environment to hazardous reagents are restricted and hazardous reagents are gradually prohibited from using in various testing methods. Thus, in this study, we developed 8 monographs from the Korean Pharmaceutical Codex by substituting the use of the hazardous reagents including ICH class 1 such as benzene, chloroform and dioxane to the use of less toxic ones like ICH class 2 or 3 reagents. We also improved their qualification and quantification performance. Among 8 monographs, the 6 newly developed TLC methods for the identification of nifedipine, oxolamine citrate, ketoprofen lysinate, chlorquinaldol, retinol acetate, and riboflavin showed a clear spot of corresponding material without any interference in spite of the replacement with ICH class 2 or 3 reagents. For the quantification of domperidone and trimebutine, HPLC methods were developed for the substitution of UV/VIS spectrometry and titrimetry, respectively. These HPLC methods were validated for the linearity, recovery, reproducibility, and inter-laboratory variations. In conclusion, the newly developed methods could be expected to become valuable tools for revising the Korean Pharmaceutical Codex.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.1
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• pp.58-64
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• 1990

This study was conducted to investigate the interaction effect of a new plant growth regulator brassinolide and auxins using several bioassay methods such as rice lamina inclination test, oat coleoptile segment growth test and radish hypocotyl elongation test. For rice lamina inclination test, the antagonistic response showed at low concentration combinations of homobrassinolide and auxins (IAA and 2,4-D), while the combinations of high concentration responsed mostly synergistic or additive effects, IAA was generally higher than 2,4-D for combination effect with homobrassinolide. For oat coleoptile segment growth test, the synergistic effect showed at IAA concentrations less than 0.1ppm while additive response exhibited above 0.3ppm regardless of homobrassinolide concentrations. In radish hypocotyl elongation test, the interaction response varied with cotyledon. The sections removed cotyledon showed mostly antagonistic effects, except for combination of homobrassinolide with IAA 3ppm. Interaction responses were Quite different from bioassay methods, particularly using experimental materials: antagonistic responses were usually shown at the section that attached growing point while these for sections that removed growing point were responded synergistic or additive effect due to unstable endogenous hormones.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.04a
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• pp.126-127
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• 2003

원예산물의 밀도나 비중은 내부성분, 숙도, 내부붕괴(internal breakdown)와 같은 생리장해에 큰 영향을 받기 때문에, 밀도를 측정함으로써 내부품질에 대한 간접적인 판정이 가능하다고 보고되고 있다. 이 연구는 수박의 밀도와 당도와의 상관관계를 구명하고자 수행하였으며, 이를 위해 밀도의 실시간 계측시스템을 개발하였다. 현재 농산물의 밀도를 어느 정도 측정 정밀도를 유지하면서도 신속하게 측정할 수 있는 방법은 부력법(platform scale method)이다. 이 방법은 일정 크기의 용기에 물을 가득 채운 후 대상물을 담가 배제된 물의 무게를 측정하여 밀도를 환산한다. 그러나 매번 측정할 때마다 물을 보충하고, 물을 계량해야하는 등 전처리과정이 복잡하고, 1회 측정하는데 3~5분 정도가 소요되는 단점이 있고, 또한 인력 측정시 반복간 오차가 클 것으로 예상된다. 따라서 이 연구에서는 이 같은 계측상의 번거로움을 해소하고 동시에 신속하고 반복간 측정정밀도를 높일 수 있도록 수박 밀도 실시간 계측시스템을 설계 제작하였다. 시스템은 투명아크릴 수조($\Phi$400$\times$500), 로드셀, 프레임, 채반, 전기모터, 제어장치 및 컴퓨터로 구성하였다. 밀도 계측은 인장형 로드셀(CAS SB-20L, Max. 20kg)을 사용하여 대기중에서와 수박을 완전히 물에 잠기도록 한 후 무게를 각각 측정하여 밀도를 환산하였다. 밀도 계측시스템에 이용한 AD변환기의 분해능은 12bit이고, 수박의 무게 측정범위를 4~10kg로 가정할 때 20kg 로드셀의 1 digit(1bit)로 발생되는 오차는 0.09~0.24%FS 이었고, 따라서 이 시스템의 밀도 해상도는 0.001g/㎤이하였다. 시스템 평가를 위해 탄력이 좋은 고무풍선에 수박 크기 정도로 물을 채워 고정채반에 넣고 밀도를 측정한 결과 1.002g/㎤을 나타냈다. 즉 물의 이론밀도인 1g/㎤에 근접한 값을 보여 정확한 밀도 계측이 가능한 것으로 판단되었다. 또한 밀도 계측시스템의 측정 반복간 정밀도를 파악하기 위해 수박 6개를 임으로 선정하여 3반복 측정 시험한 결과, 측정표준편차가 0.001~0.004g/㎤로 해상도보다는 다소 높았으나 대체로 양호한 결과를 나타냈다. 수박 35개를 이용하여 개발 계측시스템과 사람이 직접 부력법으로 밀도를 측정 비교한 결과, 계측시스템에 의해 측정된 수박 밀도가 사람이 측정했을 때 보다 낮게 측정되었다. 수박의 외관인자(무게, 길이, 직경, 체적), 밀도와 당도의 상관관계 구명시험을 위해 원예연구소 시험포장에서 재배된 삼복꿀수박 총 74개를 공시재료로 하였고, 시험은 출수일별로 10~14개씩 수확하여 외관인자, 밀도, 당도를 각각 측정하고, 이들 인자들간의 상관관계를 구명하였다. 외관인자들간에는 높은 상관관계를 보였으나, 외관인자들과 밀도, 외관인자들과 당도, 밀도와 당도와는 매우 낮은 상관관계를 나타냈다.

• Journal of the Korean Geotechnical Society
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• v.38 no.10
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• pp.31-40
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• 2022

This study compares elastic moduli calculated using two stiffness testing methods with different strain ranges to evaluate the stress-settlement characteristics of foundation support layers. Elastic moduli were calculated by the soil stiffness gauge (SSG) in the micro-strain range and the plate load test (PLT) in the medium strain range. To apply the elastic moduli obtained by the two testing methods with different strain ranges to the design and construction of foundation soils, the correlation between each measurement value should be identified in advance. As a result of the comparative analysis of the elastic moduli calculated using the two methods in weathered soil and rock, which are representative support layers in Korea, the calculated elastic moduli differed depending on the types of soil and stress conditions. For various soil types, the static elastic modulus obtained by the PLT was reduced by 56% because of the difference in the strain level of the test compared with the dynamic elastic modulus obtained by the SSG. Therefore, the results show that it is necessary to apply corrections to the stress distribution, stress level, and dynamic effect according to the ground stiffness to effectively use the SSG instead of the PLT.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.2
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• pp.98-106
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• 2003

Nondestructive test (NDT) provides much information on concrete without damage of structural functions. Of NDT methods, elastic wave propagation methods, such as ultrasonic pulse velocity (UPV) method and impact-echo (IE) method, have been successfully used to estimate the strength, elastic modulus, and Poisson's ratio of concrete as well as to detect the internal microstructural change and defects. In this study, the concretes with water-binder ratio ranging from 0.27 to 0.50 and fly ash content of 20% were made and then their longitudinal wave velocities were measured by UPV and IE method, respectively. Test results showed that the UPV is greater than the longitudinal wave velocity measured by the If method, i.e., rod-wave velocity obtained from the same concrete cylinder. It was found that the difference between the two types of velocities decreased with increasing the ages of concrete and strength level. Moreover, for the empirical formula, the dynamic Poisson's ratio, static and dynamic moduli of elasticity, and velocity-strength relationship were determined. It was observed that the Poisson's ratio and the modulus of elasticity determined by the dynamic method are greater than those determined by the static test. Consequently, for the more accurate estimation of concrete properties using the elastic wave velocities, the characteristics of these velocities should be understood.

• Korean Journal of Food Science and Technology
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• v.10 no.3
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• pp.356-360
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• 1978

To determine the total saponin extracted by Shibata method, of Ginseng jellies and candies, $vanillin-H_2SO_4$ coloring method, direct drying method and thinchrographic method were compared after samples were treated with methanol to remove sugars. Thinchrographic method was the more reproducible than direct drying method and $vanillin-H_2SO_4$ coloring method was interfered significantly by sugars.