• Journal of Welding and Joining
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• 제34권4호
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• pp.9-16
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• 2016

Metal parts are produced by conventional methods such as casting, forging and cutting, extrusion, etc. However, nowadays, with additive manufacturing (AM), it is possible to directly commercialize by means of stacking of equipment to the 3D drawing and use of high precision tools such as laser source. Thus, drawing of materials is an important aspect in delivering good products. AM deals with production of lighter aircraft parts and few more three-dimensional molds, it wish to manufacture special medical parts and want to steadily expand the new market area. The cost of related equipment and materials are still expensive and difficult to obtain on a mass production. However, the ability to make changes and lead the innovation in the paradigm of traditional manufacturing process is still effective. In this paper, we introduce metal AM and the principles of the related devices, metal powder production process, and their application.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1996년도 자동차부품 제작기술의 진보
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• pp.13-22
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• 1996

The quality requirements for metal forming products have become more strict. Machined parts, which could be produced only by cutting, can now be formed plastically. In order to reach the mechanical strength and geometrical accuracy, reasonable production technologies should be developed. In this presentation, some basic flow-press-technologies in the metal forming are introduced. Some real sample parts for a passenger can are shown and their forming plans are explained. Also problems and solutions for the production of bevel gears are discussed.

• 보존과학연구
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• 통권17호
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• pp.20-38
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• 1996

Horse armour from Dohang-ri site had been retained its original form and all iron metal fragments of armour were very completely corroded without remaining metal core. Horse armour excavated is archaeologically very important, Also it should be maintained the original form. So, only moderate treatments such as brushing and consolidation techniques were performed. The processes for the conservation is as follows : 1) preliminary investigation, 2)removal of chlorides and corrosion products, 3) consolidation with 40% ParaloidNAD-10, 4) joining and restoration

• 통합자연과학논문집
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• 제5권2호
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• pp.84-90
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• 2012

Some recommended procedures for obtaining aldehydes from carboxylic acid itself and its derivatives, which have been developed in relatively recent years, are summarized. Such procedures should provide a new practical methodology to synthesize the desired aldehyde products in high yields.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2001년도 가을 학술발표회 논문집
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• pp.299-302
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• 2001

The unique physical properties of metal fibers have led to their wide application in different fields of machinery and electrical products. Especially, stainless steel(SS) fiber is used to the reinforcement of composites, textile and nonwoven materials for improving strength and electric properties. (omitted)

• Bulletin of the Korean Chemical Society
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• 제33권7호
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• pp.2149-2155
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• 2012

A metal-free and efficient procedure for the oxidation of alcohols into the corresponding carbonyl compounds has been described using ammonium nitrate in the presence of silica sulfuric acid under mild and heterogeneous conditions. The use of non-toxic and inexpensive materials, simple and clean work-up, short reaction times and good yields of the products are among the advantages of this method.

• Advances in Traditional Medicine
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• 제10권4호
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• pp.294-303
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• 2010

We determined arsenic, lead, mercury and cadmium concentrations in Chinese herbal medicines sold in the United States by medical use parts. 54 kinds of herbal products including 9 medical use parts (radix, rhizoma, cortex, pericarpium, fructus, lignum, semen, folium, and herba) were analyzed using inductively coupled plasma-mass spectrometry for arsenic, lead and cadmium, and using mercury analyzer for mercury. Arsenic (median concentration, 0.25 mg/g), mercury (0.20 mg/g), lead (3.78 mg/g) and cadmium (0.39 mg/g) were detected in 71%, 54%, 35%, and 18% of 143 herbal medicine samples, respectively. A total of 27% and 12% of 143 products analyzed contained mercury and cadmium above the regulatory standards. Herba and folium (leaves of herbal plants) were the most contaminated parts from metals, whereas pericarpium, lignum and semen (outer layers and seeds) were less contaminated. This study suggests that metal contamination is different by medical use parts. Our findings provide further evidence that efforts to protect people using traditional remedies from metal intoxication should be made to enforce the regulatory standards.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3681-3689
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• 2013

This study explored a direct SET-photochemical strategy to construct a new family of thioene conjugated-naphthalamide fluorophore based lariat-crown ethers which show strong binding properties towards heavy metal ions. Irradiations of designed nitrogen branched (trimethylsilyl)methylthio-terminated polyethylenoxy-tethered naphthalimides in acidic methanol solutions have led to highly efficient photocyclization reactions to generate naphthalamide based lariat type thiadiazacrown ethers directly in chemo- and regio-selective manners which undergo very facile secondary dehydration reactions during separation processes to produce their corresponding amidoenethio ether cyclic products tethered with electron donating diethyleneoxy- and diethyenethio-side arm chains. Fluorescence and metal cation binding properties of the lariat type enamidothio products were examined. The photocyclized amidoenethio products, thioene conjugated naphthalamide fluorophore containing lariat-thiadiazacrowns exhibited strong fluorescence emissions in region of 330-450 nm along with intramolecular exciplex emissions in region of 450-560 nm with their maxima at 508 nm. Divalent cation $Hg^{2+}$ and $Pb^{2+}$ showed strong binding to sulfur atom(s) in side arm chain and atoms in enethiadiazacrown ether rings which led to significant enhancement of fluorescence from its chromophore singlet excited state and concomitant quenching of exciplex emission. The dual fluorescence emission responses towards divalent cations might provide a new guide for design and development of fluorescence sensors for detecting those metals.

• 한국정밀공학회지
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• 제15권2호
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• pp.124-133
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• 1998

This paper describes a research work of developing a computer-aided design of blanking and piercing for irregular-shaped sheet metal products. An approach to the development of compact and practical CAB system is based on the knowledge-based rules. Knowledge for the CAD system is formulated from plasticity theories, experimental results and the empirical knowledge of field experts. The system has been written in AutoLISP on the AutoCAD with a personal computer. Based on knowledge-based rules, the system, STRT-DES, is designed by considering several factors, such as complexities of blank geometry and punch profile, availability of press equipment and standard parts, utilization ratio which minimizes the scrap in a single or a pairwise operation, bridge width, grain orientation and design requirements which maximize the strength of the part when subsequent bending is involved. This system checks a forming feasibility with both internal and external features, a dimension of blanked hole, and a corner and a fillet radius for irregualrly shaped sheet metal products. Therefore this system can carry out a die design for each process which is obtained from results of an automated blank layout drawing with a best utilization ratio for irregular shape of product that was successful in production feasibility check module and those of an automated strip layout drawing and generate part drawings and the assembly drawing of die set in graphic forms.

• 한국식품과학회지
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• 제34권1호
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• pp.136-139
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• 2002

검정현미에 내포한 특이한 향기성분을 토대로 수입산 또는 국내산인지의 여부를 전자코로 분석하였다. 주성분 분석 결과 전반적으로 수입산과 국내산의 판별이 뚜렷하게 구별 가능하였다. 또한 인공신경망 분석 프로그램을 이용하여 학습시켜 원산지를 모르는 시료를 분석한 결과 국내산 검정현미가 수입산인지 국내산인지를 구별할 수 있었다. E-Nose 5000을 이용한 결과는 69종의 국내산 검정현미를 국내산으로 판별한 경우가 64종으로 92.75%이었고, 13종의 수입산 검정현미를 수입산으로 판별한 경우는 11종으로 92.31%의 높을 확률로 metal oxide sensor로만 구성된 전자코의 판별정도보다 더 정확하게 구별할 수 있었다.