• 자원리싸이클링
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• 제30권3호
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• pp.18-29
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• 2021

백금족 금속(Platinum Group Metals, PGMs)은 화학적 저항성은 물론 전기·열전도성이 뛰어나 촉매, 전자기기, 전극, 전기기기, 연료전지, 고온 소재 등 광범위한 응용 분야에 사용된다. 일반적으로 백금족 금속은 구리와 니켈의 황화광과 관련되어 있으므로 백금족 금속의 상대적인 농도에 따라 주산물로 생산되거나 니켈과 구리의 부산물로 생산된다. 특히 이러한 자원들은 남아프리카와 러시아 같은 나라들에 편재되어 있으며, 백금족 금속의 연간 공급량은 500톤 미만이다. 이와 같은 백금족 금속의 한정된 공급량을 고려하면 향후에 백금족 금속의 공급 리스크가 증가할 것이다. 따라서 폐촉매와 같은 2차 자원으로부터 백금족 금속을 회수하는 것이 매우 중요하다. 본 논문에서는 백금족 금속의 제련 기술과 리사이클링 기술에 대하여 고찰하였다.

• 자원리싸이클링
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• 제19권5호
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• pp.3-12
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• 2010

고순도 백금족 금속은 첨단 산업의 기초 소재로 향후 국내 산업의 지속적인 발전에 꼭 필요하다. 국내에는 백금족 금속을 함유한 광물이 전무하므로 백금족 금속을 함유한 여러 폐자원으로부터 백금족 금속을 고순도로 분리 정제할 수 있는 기술의 개발이 시급하다. 백금족 금속의 화학적 성질과 침출거동에 대한 자료를 문헌에서 조사하였다. 또한 향후 백금족 금속과 같은 난용금속의 침출에 이용이 증가할 것으로 예상되는 염소가스를 취입한 염산용액의 열역학적 해석 방법을 소개하였다, 백금족 금속간의 화학적 성질과 침출거동의 미세한 차이정올 이용하면 백금족 금속을 고순도로 회수할 수 있는 기술 개발이 가능하다.

• Asian-Australasian Journal of Animal Sciences
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• 제21권2호
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• pp.299-306
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• 2008

This study was designed to develop microencapsulated Korean mistletoe extract, to determine the stability in vitro and to examine its application in milk. Coating materials used were polyglycerol monostearate (PGMS) and medium-chain triacylglyderol (MCT). The highest efficiency of microencapsulation was 78.3% with 15:1:40 (w/w/v) as PGMS : mistletoe extract : distilled water and 66.1% with 15:1 (w/w) as MCT : mistletoe extract. The size of microcapsule was about 30.0 and $19.5{\mu}m$ with PGMS and MCT, respectively. When microcapsules of mistletoe extract were incubated in simulated gastric fluid at pH 2 for 60 min, 14.8 and 17.2% of lectin was released from capsules which were coated with PGMS and MCT, respectively. Comparatively, 83.2 and 87.3% of lectin was released in simulated intestinal fluid (pH 8) after 60 min incubation of capsules coated with PGMS and MCT, respectively. The subsequent study determined the changes of physicochemical and sensory characteristics of milk with fortification of the mistletoe extract microcapsules during 12 day storage. TBA value was significantly lower in microcapsule-added groups than in the uncapsulated mistletoe extract-added group during the storage. When 100 ppm microencapsulated mistletoe extract was added, the L-, a- and b- values and viscosity were not significantly different from those of the control. In addition, the release of lectin from mistletoe extract over 12 days was 8.3 and 9.5 mg/100 ml in milk containing microcapsules made by PGMS and MCT, respectively. All sensory attributes showed a significant difference in uncapsulated mistletoe extract-added milk compared with other groups. The present study indicated that microcapsules of Korean mistletoe extract could be applied to milk and microcapsules coated with PGMS were effectively released in a simulated intestinal environment.

• 한국해양공학회지
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• 제31권6호
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• pp.379-387
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• 2017

In this study, a pile-guide mooring system (PGMS) was designed for an offshore liquefied natural gas bunkering terminal (LNG-BT), which is an essential infrastructure for large LNG-fuelled ships. The PGMS consisted of guide piles to restrict five motions of the floater, except for heave, as well as a seabed truss structure to support the guide piles and foundation piles to fix the system to the seabed. Singapore port was considered for a case study because it is a highly probable ports for LNG bunkering projects. The wave height, current speed, and wind speed in Singapore port were investigated to calculate the environmental loads acting on the hull and PGMS. A load and resistance factor approach was used for the structural design, and a finite element analysis was performed for design verification. The steel usage of the PGMS was analyzed and compared with the material usage of a gravity-based structure under similar LNG capacity and water depth criteria. This paper also describes the water depth limit and wave conditions of the PGMS based on estimation of the initial investment and the present value profit difference. It suggests a suitable LNG-BT support system for various design conditions.

• 한국군사과학기술학회지
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• 제18권5호
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• pp.558-565
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• 2015

The current methods, such as Binomial Probability Distribution or T-test, to calculate the number of samples of Precise Guided Missiles(PGMs) for test and evaluation are statistically problematic to make reasonable decisions thus use the budget efficiently. Also, the method to verify an accuracy rate of the PGMs using these old methods seems to be lack of objectiveness. This paper presents an effective, efficient solution adapted from the clinical medicine testing method of healthcare industry research, which may overcome our problems. This method considers and addresses both manufacturers' and consumers' risk simultaneously. By taking into account the weapon system project characteristics which take a relatively longer time and require higher-level budget, this approach also suggests a reasonable and feasible method to determine the amount of samples of the PGMs and making a criterion to verify an accuracy rate of the missiles that are required to test. Thus, this method is expected to contribute to acquisition and operations of high-reliability PGMs by MND and its field-users.

• Asian-Australasian Journal of Animal Sciences
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• 제15권12호
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• pp.1808-1812
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• 2002

The present study was carried out to examine the efficiency of microcapsules and a stability of lactase in vitro in the simulated gastric and intestinal conditions. As a coating materials, medium-chain triacylglycerol (MCT) and polyglycerol monostearate (PGMS) were used. The highest efficiency of microencapsulation was found in the ratio of 15:1 as coating to core material with both MCT (91.5%) and PGMS (75.4%). In a subsequent experiment, lactose content was measured to study a microcapsule stability. Lysis of microcapsules made by MCT in simulated gastric fluid was proportionally increased such as 3% in pH 5 and 11% in pH 2 for 20 min incubation. In the case of PGMS microcapsulation, 11-13% of lactose was hydrolyzed at 20 min in all pHs and also very little amount (less than 3%) of lactose was hydrolyzed after 20 min in all pHs. The highest percentages of lactose hydrolysis in MCT and PGMS microcapsules were 68.8 and 60.8% in pHs 7 and 8 during 60 min, respectively. Based on our data, the lactase microcapsules seemed to be stable when they stay in the stomach, and hydrolyzed rapidly in small intestine where the bile acid was excreted.

• 한국작물학회지
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• 제52권3호
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• pp.281-288
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• 2007

Photoperiod sensitive genetic male sterile (PGMS) rice is sterile mutant controlled by photoperiod. A PGMS mutant 920S was sterile grown under long-day (LD) photoperiod (14 h light/10 h dark) but fertile grown under short-day (SD) photoperiod (10 h light/14 h dark). Proteome analysis revealed that 12 protein spots were differentially expressed in the spikelets of 920S plants either treated with LD or SD photoperiod. Among these proteins, three proteins including chlorophyll a/b binding protein, vacuolar ATPase ${\beta}-subunit,\;{\alpha}-tubulin$ and an unknown protein were more than three-fold abundant in the spikelet of the SD-treated plants than those of the LD-treated plants. On the other hand, eight proteins including acetyl transferase, 2, 3- biphosphoglycerate, aminopeptidase N, pyruvate decarboxylase, 60S acidic ribosomal protein and three unknown protein spots were more abundant in the spikelets of the LD-treated plants than those of the SD-treated plants. The results suggest that the observed proteins may be involved in sterile or fertile pollen development under LD or SD photoperiod respectively in the PGMS mutant rice.

• 품질경영학회지
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• 제48권1호
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• pp.215-225
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• 2020

Purpose: The purpose of this study was to show current states of domestic Precision Guided Missile(PGM) by analyzing Live-fire test results using general methods to get the Confidence Levels. Methods: Live-fire test results were used to get Confidence Levels of PGM. The Confidence Levels were derived by two general methods. The first method was Binomial distribution and second was convergence of Hypergeometric distribution and Bayes' rule. Results: The results of this study are as follows; The more Live-fire tests of PGM are performed, the higher Confidence Level of PGM will be estimated. And the number of Live-fire tests are related to a unit price of PGM. This results means that the increase of live-fire test, which is useful data for preparation and evaluation of Development Tests / Operation Tests for PGMs, is only way to enhance the Confidence Levels of each PGMs. Conclusion: This study shows the relationship between the Live-fire tests and Confidence Levels of PGMs and it will be used on Live-fire Test & Evaluation of PGMs for reference.

• Archives of Pharmacal Research
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• 제26권10호
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• pp.874-879
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• 2003

The present study was carried out to examine the stability of microencapsulated ascorbic acid in simulated-gastric and intestinal situation in vitro and the effect of microencapsulated ascorbic acid on iron bioavailability. Coating materials used were polyglycerol monostearate (PGMS) and medium-chain triacylglycerol (MCT), and core materials were L-ascorbic acid and ferric ammonium sulfate. When ascorbic acid was microencapsulated by MCT, the release of ascorbic acid was 6.3％ at pH 5 and 1.32％ at pH 2 in simulated-gastric fluids during 60 min. When ascorbic acid was microencapsulated by PGMS, the more ascorbic acid was released in the range of 9.5 to 16.0％. Comparatively, ascorbic acid release increased significantly as 94.7％ and 83.8％ coated by MCT and PGMS, respectively, for 60 min incubation in simulated-intestinal fluid. In the subsequent study, we tested whether ascorbic acid enhanced the iron bioavailability or not. In results, serum iron content and transferring saturation increased dramatically when subjects consumed milks containing both encapsulated iron and encapsulated ascorbic acid, compared with those when consumed uncapsulated iron or encapsulated iron without ascorbic acid. Therefore, the present data indicated that microencapsulated ascorbic acid with both PGMS and MCT were effective means for fortifying ascorbic acid into milk and for enhancing the iron bioavailability.

• Journal of Dairy Science and Biotechnology
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• 제21권2호
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• pp.105-113
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• 2003

This study was carried out to investigate the addition of Pueraria derived isoflavone into milk by means of microencapsulation technique. The yield microencapsulation sensory attributes, and capsule stability of Pueraria derived isoflavone microcapsules in milk were measured during 12 days. Coating materials used was polyglycerol monostearate(PGMS. The encapsulation yield of Pueraria derived isoflavone was 72.5% with PGMS when the ratio of coating material to core material was 15:1. The rate of pueraria derived isoflavone release was 15, 20, and 25% when stored at 4, 20, and $30^{circ}C$ for 12 days in milk respectively. In sensory evaluation, beany flavor and color of microcapsuled Pueraria derived isoflavone added milk were significantly different from control and uncapsuled Pueraria derived isoflavone added milk, however, bitterness was not significantly different. In vitro study, microcapsules of pueraria derived isoflavone in simulated gastric fluid with the range of 3 to 6 pHs were released 3.0${\sim}$15.0%, however, the capsules in simulated intestinal fluid with pH 7 were released 95.7% for 40 min incubation time. In conclusion, this study provided that PGMS as coating materials was suitable for the microencapsulation of Pueraria derived isoflavone, and the capsule containing milk was not affected with sensory attribute.