• Economic and Environmental Geology
• /
• v.47 no.6
• /
• pp.645-655
• /
• 2014

In order to obtain pure metallic Te from gold concentrate, roasting treatment, hypochlorite leaching, Fe removal and electrolysis experiments were carried out. The contents of Au, Ag and Te from the concentrate sample and roasted sample were much more soluble in the hypochlorite solution than in aqua regia digestion, whereas the metals Pb, Zn, Fe and Cu were easier to leach with the aqua regia than the hypochlorite. With the addition of NaOH in the hypochlorite leaching solution prior to electrolysis, the Fe removal rate achieved was only 96% in the concentrate sample, while it reached 98% in the roasted sample. The results of electrolysis for 240 min, 98% of the metallic copper was recovered from the concentrate sample, while 99% was obtained from the roasted sample due to the removal of S by roasting. The amount of anode slime was also greater in the electrolytic solution with the roasted sample than with the concentrate sample. The results on the anode slime after the magnetic separation process showed the amount of metallic pure native tellurium recovered was greater in the roasted sample than in the concentrate sample.

• Journal of Soil and Groundwater Environment
• /
• v.15 no.5
• /
• pp.8-15
• /
• 2010

The purpose of this research is to check the validation of an auto-analysis method combined with aqua regia digestion apparatus for improvement of water distillation method used as a fluorine test of soil. Fluorine contents of CaO used in the pretreatment course of water distillation method were 120 mg/kg ~ 5,064 mg/kg at the blank test, which was exceeded up to maximum 12.5 times of the soil standard, so it was estimated due to a effect of fluorine existing as impurities of CaO. The recovery test of the same samples indicated that water distillation method and auto-analysis method were 134.5mg/kg and 161.7mg/kg respectively, the recovery ratio of the latter was 16.8% higher than the formal. The validation test of two methods satisfied the standard, but auto analysis method was excellent more than distillation method. Also, auto analysis method could save a analysis time up to maximum 4.7 times by comparison with water distillation method.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.5
• /
• pp.899-905
• /
• 2009

IPTV service is one of the representatives for the integration of broadcasting industry and communication industry, which also can meet users' various demands and provide efficient service. As the increasing number of IPTV users and contents servers, it is necessary to provide the safety authority system to prevent the illegal audio-visual, incorrect audio-visual authority, and illegal authority control. This thesis puts forward PKI(public Key Infrastructure) as the foundation key production mechanism. Through this mechanism, the key can be transferred safely to users and authenticate the ID of users and contents servers. In a word, our system can provide safe and efficient service for mutual authentication.

• The Journal of Internal Korean Medicine
• /
• v.18 no.2
• /
• pp.112-130
• /
• 1997

This study has been carried out to investigate the cause, pathological mechanism and treatment of stroke in Oidaibiyo(外臺秘要), written by Wangdo(王燾). The results were follows : 1. Oidaibiyo(外臺秘要), which is written by Wangdo gives an account of the symptomatic degree of intensity and diachronic procedure in the chapter of stroke. 2. The cause of stroke is quoted mainly from External Wind(外來風邪), and the hyper-sexual intercourse, hyperalimentation, hyper -consciousness, excessive lavour and so forth as additional. And personal character and external effect, like the climate conditions are also much affected the outbreak of stroke. 3 With respect to the diagnosis of stroke, pulse means here quoted from its conception in Chungumyobang(千金要方) Jebungwonhuron(諸病源候論), and pulse plays an important role in diagnosis of stroke. 4. The treatment for stroke generally attaches much importance to medicine therapy. The concrete cure, BalhanGeopungbub(發汗祛風法) has been mainly available, and the usage of Cheongyulyak(淸熱樂) has been increased, contray to formal.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2009.05a
• /
• pp.781-784
• /
• 2009

IPTV, which is convergence of Communication and Broadcasting, has improved quickly recently. This service can provide high quality and various services to their customers, such as choosing channels freely, VOD and many kinds of Interactive service. As the technology of IPTV rapid development, more and more people worry about its disadvantages during the spread and apply, for instance, the illegal application, illegal copy, access authority abuse and the danger of the IPTV contents. This paper will provide the solution to solve these problems, through the Public Key Certificate of PKI(Public Key Infrastructure) and the Attribute Certificate of PMI(Privilege Management Infrastructure).

• Proceedings of the KSR Conference
• /
• 2007.11a
• /
• pp.1236-1241
• /
• 2007

The feasibility of soil washing was investigated in the laboratory to treat heavy metals-contaminated railway soil. Various organic acids including ethylene diamine tetraacetic acid (EDTA) and citric acid as well as inorganic acids such as hydrochloric acid (HCl) and phosphoric acid were tested to evaluate washing efficiency. Generally, inorganic acid showed higher removal efficiency compared to organic acids. Specially, EDTA, which are well known as most effective washing agent to remove heavy metals from soil, was not efficient to remove heavy metals in this study. Among washing agents tested in this study, HCl was most effective. The removal of Cd, Cu, and Pb was high, however, that for Zn and Ni was less than 30% with 0.5 M HCl. This difference comes from analytical methods (Korean Standard Test Method for Soil). Aqua regia was used to extract Zn and Ni, however 0.1 N HCl was used for other metals. As a result, simple washing technology is not effective, to treat railway contaminated soil with heavy metals.

• Journal of the Korean Chemical Society
• /
• v.15 no.4
• /
• pp.191-197
• /
• 1971

Ruthenium content in highly purified palladium metal (99.9%) was determined by counting $^{105}Rh$ nuclide which was produced by $^{104}Ru(n,{\gamma};{\beta}^-)^{105}Rh$ nuclear reaction. Palladium sample and ruthenium standard were irradiated by neutron with the Pneumatic Transfer System of TRIGA MARK II reactor. Palladium and ruthenium were dissolved by treating with aqua-regia and by fusing with sodium peroxide flux respectively. $^{105}Rh$ was separated through anion and cation exchange resin columns. The ruthenium content was determined by comparing the $^{105}Rh$ activities, obtained from the palladium sample, with that from pure ruthenium standard. The detection limit of ruthenium by the present method is about 1 ppm of ruthenium in 10 mg of palladium, which is approximately 40 times more sensitive than that of the conventional radioactivation method which employs $^{102}Ru(n,{\gamma})^{103}Ru$ nuclear reaction.

• Journal of Korean Medical classics
• /
• v.19 no.1 s.32
• /
• pp.211-214
• /
• 2006

북송(北宋)의 교정의서국(校正書局)에서는 치평(治平) 3년에 왕수(王洙)가 발견한 ${\ulcorner}$금궤옥함요약방(金玉函要略方)${\lrcorner}$을 다시 정리하여 장중경(張仲景)의 ${\ulcorner}$금궤방론(金方論)${\lrcorner}$이라는 이름으로 발간하면서, 그 서문 뒤에 ‘중경금궤록(仲景金)’이라고 언급하였는데, 필자는 역사적인 각도에서 금궤라는 명칭의 연원과 금궤 금궤록이 ${\ulcorner}$금궤방론(金方論)${\lrcorner}$서문 뒤에 언급된 ‘중경금궤록’와 어떤 관계가 있는가에 대하여 고찰하여 보았다. 금궤라는 명칭은 귀중한 서적이나 물품을 보관하던 장소를 지칭하는 말로 사용되었는데, 서명으로는 ${\ulcorner}$한서(漢書) 예문지(藝文志)${\lrcorner}$에 ${\ulcorner}$감여금궤(堪輿金)${\lrcorner}$라는 명칭으로 최초로 등장하며, 의서로는 ${\ulcorner}$진서(晋書)${\lrcorner}$갈홍전(葛洪傳)에 ${\ulcorner}$금궤약방(金藥方)${\lrcorner}$이라는 서명으로 최초로 나온다. 현존하는 ${\ulcorner}$도장(道藏)${\lrcorner}$ 제(第)6부(部) 동현부(洞玄部) 옥결류(玉訣類)에 있는 ‘신선복이단석행약법(神仙服餌丹石行藥法)’의 일부분의 내용이 갈홍(葛洪)의 ${\ulcorner}$포박자(抱朴子)${\lrcorner}$와 서로 같고, 이것이 ${\ulcorner}$금궤록${\lrcorner}$일 가능성이 매우 높다. 손기(孫奇) 등 송(宋)의 신하가 ${\ulcorner}$금궤방론(金方論)${\lrcorner}$ 서문 뒤에 인용한 내용은 ${\ulcorner}$주후비급방${\lrcorner}$ 서문과 ${\ulcorner}$포박자내편(抱朴子內篇) 잡응(雜應)${\lrcorner}$의 내용과 서로 일치한다. 송(宋)의 신하가 인용한 서문은 갈홍(葛洪)이 쓴 것을 다시 인용하였을 가능성이 높고, 그 중에 ${\ulcorner}$금궤록${\lrcorner}$과 관련이 있는 내용은 장중경(張仲景)과는 아무 상관도 없다.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2018.06a
• /
• pp.93.2-93.2
• /
• 2018

최근 기후 변화 문제로 $CO_2$배출량 억제 정책에 따라 열전재료가 다양한 분야에 크게 주목 받고 있다. 열전 모듈은 전류를 흘려 온도차를 발생시키는 펠티어 효과와 온도차를 전력으로 변환하는 제백 효과를 이용한다. 열전발전용에 적용되는 상용 열전모듈의 경우, 열전소자의 접합부의 수는 수십 개 이상이다. 따라서 단 한 개의 접합 불량 열전소자가 모듈 전체의 열전성능에 큰 영향을 미친다. 현재 상용화 된 Bi-Te계 열전 모듈은 Bi-Te의 Te와 Sn계 솔더의 주성분인 Sn이 $250^{\circ}C$ 부근에서 취성의 Sn-Te계 금속 화합물을 형성한다고 알려져 있다. 이 때 생성된 Sn-Te 화합물은 열전모듈의 접합강도를 약화시키고 이로 인해 열전모듈의 접합 신뢰성을 크게 저하 시킬 수 있다. 이를 해결하기 위해 솔더와 소자 사이에 확산방지층이 적용되고 있으며, 이 중에서 니켈합금이 가장 널리 적용되고 있다. 니켈층을 형성시키는 방법 중에서, 무전해 도금법은 간단하게 열전소자 표면 위에 도금 층을 균일한 두께로 만들어 낼 수 있다. 하지만, 니켈 도금층과 Bi-Te 소자 간에 화학적 결함이 존재하지 않기 때문에, 무전해 니켈 도금층의 밀착성이 떨어진다. 이 때. 소자 표면에 거칠기 효과(anchor effect)를 부여하기 위해 물리적 샌딩법을 사용하는데 이 방법의 경우 소자에 크랙 같은 손상을 미쳐 열전모듈의 신뢰성 저하를 가져온다. 그러므로 거칠기 효과를 부여하면서 소자에 손상을 최소화하는 습식 식각법을 개발하여 Bi-Te계 열전소자의 표면 조도를 조절하고 무전해 Ni-P 도금을 실시하였다. 그리고 열처리 유무에 따른 열전모듈의 접합강도를 측정하였으며, 제작한 열전 모듈의 접합부 및 파단부의 계면 분석하여 무전해 Ni-P도금을 위한 습식식각법(wet etching법)에 대하여 검토하였다. N-type은 질산과 구연산의 혼합수용액에, P-type은 왕수에 습식 식각처리를 해서 적당히 표면 조도를 조절한 후에 EPMA로 분석을 해본 결과 니켈 도금층과 Bi-Te 소자 간에 anchor effect가 부여 된 것을 확인했다. 습식 식각에 의해서 제조된 열전모듈의 접합강도는 종래의 알루미나 샌딩법으로 제조한 열전모듈 보다 높은 접합강도를 나타내었다.

• Resources Recycling
• /
• v.20 no.4
• /
• pp.52-57
• /
• 2011

Present paper reports a new method to separate the electrolyte membranes and carbon paper without using ultrasonic waves and stirring. In this method, these were separated from fuel cell membrane-electrode assembly(MEA) using the distilled water, butanol and surfactant by dipping method without the dispersion of catalyst particles. Separated carbon paper catalysts and fuel cell Pt/C catalysts were heated in aqua regia at $80{\sim}85^{\circ}C$ and added to precipitant. After calcination, Pt metal was recovered which might be used in fabricating new fuel cells.