• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.3
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• pp.376-381
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• 2012

This paper deals with application of instrumented indentation technique for quality inspection methodology for automobile component. For this, the instrumented indentation tests were performed the normal and cracked compressor journal, which is made from spheroidal graphite cast iron and utilized in air-conditioning system. And the Brinell hardness was estimated using the unloading slope and maximum indentation force. With the aid of Normal distribution, this Brinell hardness was statistically compared and analyzed with hardness measured by indentation hardness tests. Also, application possibility of reliability-based quality inspection criteria for compressor journal was evaluated through the probabilistic analysis for the Brinell hardness estimated by instrumented indentation technique.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.05a
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• pp.31-31
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• 2015

본 연구는, TAB(Tape Automated Bonding)접속이나 Flip Chip 접속에 의한 패캐징을 실현시키기 위해, 실리콘 웨이퍼 표면에 구리 필러 및 주석 합금을 전기 도금법으로 형성하는 전기 접점용 범프에 관한 것이다. 본 연구에서는, 균일 범프 두께, 범프 표면의 균일화, 범프 내의 보이드 발생 문제 해결, 균일한 합금 조성 및 도금 속도의 고속화를 위해, Cu 도금액 및 Sn-Ag 도금액의 첨가제에 의한 표면 형상의 제어를 중심으로 그 성능에 대해 보고한다.

• 한국가시화정보학회:학술대회논문집
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• 2006.12a
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• pp.102-108
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• 2006

The three-dimensional flows in the Weis-Fogh mechanism are studied by flow visualization and numerical simulation by the discrete vortex method. In this mechanism, two wings open, touching their trailing edges (fling), and rotate in opposite directions in the horizontal plane. The structure of the vortex systems shed from the wings is very complicated and their effects on the forces on the wings have not yet been clarified. The discrete vortex method, especially the vortex stick method, is employed to investigate the vortex structure in the wake of the two wings. The wings are represented by lattice vortices, and the shed vortices are expressed by discrete three-dimensional vortex sticks. The vortex distributions and the velocity field are calculated. The pressure is estimated by the Bernoulli equation, and the lift on the wing are also obtained.

• Journal of KIISE
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• v.45 no.2
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• pp.126-133
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• 2018

The recommender system (RS) has emerged as a solution to overcome the constraints of excessive information provision and to maximize profit and reputation for information providers. Although the RS can be implemented with various approaches, there is no study on how to appropriately utilize the information generated from the review of the recommended object. We propose a method to improve the performance of RS by using cluster information generated from online review. We implemented the proposed method and experimented with real data, and confirmed that the performance is significantly improved compared to the existing approaches.

• Journal of the Korean Chemical Society
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• v.18 no.5
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• pp.329-340
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• 1974

Sulfadiazine, $C_{10}H_{10}N_4O_2S$, forms monoclinic crystals of space group $P21}c$ from a mixture of acetone and ethanol with $a=13.71{\pm}0.04,\;b=5.84{\pm}0.03,\;c=15.11{\pm}0.05{\AA},\;{\beta}=115.0{\pm}0.3^{\circ}$, and four molecules per cell. Three dimensional photographic data were collected with $CuK\alpha$ radiation. The structure was determined using Patterson and Fourier synthesis methods and refined by block diagonal least-squares methods with isotropic thermal parameter for all non-hydrogen atoms. The final R value was 0.15 for the 1517 observed independent reflections. The dihedral angle between the planes through the benzene ring and the pyrimidine ring is $76^{\circ}$. The conformational angle formed by the projection of the S-C(5) bond with that of N(1)-C(1) where the projection is taken along the S-N(1) bond is $77^{\circ}$. The imino nitrogen atom, N(1), and pyrimidine nitrogen atom, N(3), form intermolecular $N-H{\cdots}N$ hydrogen bond between the molecules related by center of symmetry. Amino nitrogen atom, N(4), forms two intermolecular $N-H{\cdots}O$ hydrogen bonds, with O(1) and O(2) atoms of different molecules separated by b. A two dimensional network of hydrogen bonds form infinite molecular sheets parallel to the (100) plane. Adjacent sheets are bound together by van der Waals forces.

• Journal of Food Hygiene and Safety
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• v.26 no.1
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• pp.12-15
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• 2011

A method based on high-performance liquid chromatography (HPLC) with ultraviolet detection has been developed to quantify coenzyme Q10 (CoQ10) in raw materials and dietary supplements. Single-laboratory validation has been performed on the method to determine linearity, selectivity, accuracy, limits of quantification (LOQ) and repeatability for CoQ10. An excellent linearity (r=0.999) was observed for CoQ10 in the concentration range $15.625{\sim}500\;{\mu}g/ml$ in dietary supplement. Observed recovery of CoQ10 was found to be between 98.33 and 99.38%. LOQ was found to be $250\;{\mu}g/ml$ Repeatability precision for CoQ10 was between 0.15 and 0.21% relative standard deviation (RSD). Further, limited studies showed that some adulterants and degraded material could be satisfactorily separated from CoQ10 and identified.

• Journal of the Korean Chemical Society
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• v.42 no.2
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• pp.214-219
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• 1998

Dynorphin B analogues, $[Arg^{11}, D-Ala^{12}]$dynorphin B, $[D-Ala^2, Ala^6, Arg^{11}, D-Ala^{12}]$dynorphin B, and dynorphin B (1-11) were synthesized by solid-phase method. A chloromethylated polystyrene resin cross-linked with 2% divinylbenzene was substituted with Thr in ethanol to contain 1.20 mmol Thr/g of resin. All amino groups of amino acids were protected with t-Boc group and 2,6-dichlorobenzyl and nitro groups were used to protect the side chains of Tyr and Arg, respectively. Stepwise synthetic method was applied for synthesis of the products. Dicyclohexylcarbodiimide (DCC) and 1-hydroxybenzotriazole (HOBT) were used as the coupling reagents. The crude peptides were purified by gel filteration on Sephadex LH-20 column $(2 \times 50 cm)$ using MeOH/MeCN (3/1) and then characterized with HPLC, amino acid analyzer.

• Korean Journal of Materials Research
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• v.11 no.12
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• pp.1020-1027
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• 2001

Powder type Ag system insert metals were manufactured by mechanical alloying method. Alloying method was the ball milling process using zirconia ball media, and all alloying variables were constant except the milling time. The milling times were selected 24, 48 and 72 hours. The insert metals made by milling method were observed using scanning electron microscope and x-ray analyses. And also, the evaluation of wettability and microstructures of the insert metals were conducted to investigate the characteristics of the brazed joint. The wettability of the insert metals made by milling of 48 hours, was the best condition. And the insert metals contained Cd shows good wettability, however, there was the oxides residue on the brazing test specimen. The microstructures of the manufactured and the commercial insert metals were almost same displaying the Cu- rich proeutectic and Ag-rich eutectic. Further, there were some porosities. The 48 hours alloyed insert metal was exhibited the most sound brazed joint without containing porosity due to the superior wettability and good alloying condition.

• Journal of Welding and Joining
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• v.35 no.1
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• pp.55-60
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• 2017

There are many Industry Code and Standard (ICS) for Structural Integrity Assessment (SIA) on welded structure with defect. The general ICSs, such as R6, BS 7910 and API 579-1/ASME FFS-1, provide equations to determine the upper bound residual stress profiles based on collections from many literatures. However, these residual stress profiles used in the SIA cause the conservative design for welded structures. In this study, the structural integrity assessment for girth weld in pipeline has been conducted based on fracture mechanics. In addition, thermo-elastic plastic FE analysis was performed for evaluating the residual stress of girth weld in pipeline. The weight function solution is used to determine the stress intensity factor using the residual stress profile obtained by the FE analysis. This approach can account for redistribution and relaxation of residual stress as the defects grow. In order to the evaluate quantitative comparison between BS 7910 and weight function solution, structural integrity assessment determining allowable crack size on cracked pipe was performed with failure assessment diagram.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2007.05a
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• pp.168-171
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• 2007

현재의 국가연구개발사업 협약체결은 협약당사자간 서류 협약서를 주고받으면서 불필요한 시간이 소모되어 연구비 지급 지연이 잤다. 또한 각 연구관리전문기관에서 연구의 효율성을 높이기 위해 이용하는 연구관리지원시스템에서도 이러한 기능이 개발되지 않고 있는 실정이다. 따라서 본 연구에서는 연구관리지원시스템 활용성 제고 위한 사용자중심의 전자협약시스템 구현하고자 한다. 전자협약시스템 도입으로 협약서류를 제출하지 않고 인터넷 시스템을 이용하여 업무를 신속하게 처리할 수 있어 연구자들에게 행정적 부담을 대폭 완화하고 연구기간을 충분히 활용할 수 있을 것이다. 특히, 이 시스템은 전자서명법에 의한 전자공인인증서를 사용함으로써 협약체결에 따른 법률적 효력을 유지하면서, 연구기관의 협약서 보관 및 관리에 드는 인력, 비용과 시간이 절약되어 선진연구관리기법의 정착을 통한 국가연구개발사업 생산성 향상에 크게 기여할 것으로 기대된다.