• 대한지역사회영양학회지
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• 제21권2호
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• pp.140-151
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• 2016

Objectives: This study was performed to examine the consumption patterns of convenience food at convenience stores, dietary habits, and perception as well as knowledge of food additives among university students. Methods: Subjects were 352 university students in Cheongju, Korea, and data was collected by a self-administered questionnaire. They were divided into three groups according to the frequency of consumption of convenience food at convenience stores: 79 rare (${\leq}1$ time/month), 89 moderate (2-4 times/month) and 184 frequent (${\geq}2$ times/week). Results: More subjects from the frequent consumption group lived apart from parents (p<0.001) and possessed more pocket money (p<0.01). Frequent consumption group consumed noodles, Kimbab, and sandwich & burger significantly more often (p<0.001, respectively) than others. In addition, frequent consumption of convenience foods at convenience stores was associated with frequent breakfast skipping (p<0.05), irregular meal time (p<0.01), snacking (p<0.05), and eating late night meal (p<0.001). More from the rare consumption group had heard about food additives previously compared to the frequent consumption group (79.7% vs. 63.6%, p<0.01). Frequent consumption group showed significantly higher score than did the rare consumption group for the following questions: monosodium glutamate is harmful to your health (p<0.05), food additives are necessary for food manufacturing (p<0.005), food additives need to be labeled on products (p<0.05), there is no food additive at all if labeled as no preservatives, no coloring, and no added sugar (p<0.05). There was a significant difference in degrees of choosing products with less food additives depending on the consumption pattern. Conclusions: Our results provided a better understanding of the factors associated with frequent consumption of convenience foods at convenience stores among university students and will be useful to develop a nutrition education program for those who are more prone to consume convenience foods.

• 한국식품저장유통학회지
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• 제7권3호
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• pp.249-255
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• 2000

응고제의 종류에 따른 천연물 첨가 두부의 제조특성을 알아보았다. 수율과 물성, 관능검사결과 등을 고려한 결과 $MgCl_2$는 0.2%, $CaCl_2$ 0.4%, $CaSO_4$는 2.0%가 최적농도로 선택되었다. 또한 천연물 첨가농도는 당근 4%, 오이 10%, 시금치 1.0%, 녹차말차 0.05%를 최적농도로 선정하였다. GDL을 응고제로 사용한 천연물 첨가두부의 색도도 응고제의 종류에 따라서도 차이를 보이지 않았으며 두부의 물성에도 크게 영향을 미치지 않았다. 당근, 오이, 시금치 첨가두부에서 색소의 함량은 $MgCl_2$, $CaCl_2$를 응고제로 사용한 두부에서 함량이 높았으나 녹차 첨가두부의 polyphenol 함량은 $CaSO_4$, GDL를 응고제로 사용한 두부가 높은 값을 보였다.

• 한국식품저장유통학회지
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• 제7권3호
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• pp.256-261
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• 2000

두부의 품질을 고급화하고 다양화하기 위한 방안의 하나로 천연물을 첨가한 두부를 제조하여 기능성의 부여와 함께 기호성을 향상할 수 있는 천연물 첨가두부를 제조하였다. 천연물로는 클로로필과 카로티노이드를 가지고 있는 당근과 오이, 시금치 그리고 카테킨등에 의한 기능성이 확인된 녹차를 천연 첨가물로 선정하였다. 천연물 첨가두부의 수율은 무첨가 두부에 비하여 감소되었으나 색상에 의한 기호성의 증대를 확인할 수 있었다. 천연물 첨가에 따라 두부의 조직특성은 큰 변화가 없었으나 기호도 향상의 효과가 있었다. 최적 첨가 농도는 당근 4%, 오이 10%, 시금치 1.0%, 녹차는 0.05%로 결정할 수 있었다. 저장 중 총균수의 변화는 시금치와 녹차 첨가두부가 저장초기 균의 생육을 저지하여 저장성이 있는 것으로 나타났다.

• 청정기술
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• 제5권2호
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• pp.45-52
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• 1999

알루미늄 생산의 폐기물로 나오는 적니를 플라스틱의 Filler로서 재활용하기 위한 연구를 수행하였다. 여러가지 플라스틱에 적니를 첨가하여 본 결과 고밀도폴리에틸렌(HDPE), 저밀도 폴리에틸렌(LDPE) 및 폴리프로필렌(PP)에 적니가 Filler로서 사용 가능한 것으로 나타났다. 적니가 플라스틱에 첨가됨에 따라 플라스틱은 다른 안료의 첨가 없이도 붉은 고동색을 나타내었고 인장탄성율 등은 증가하였으나 내충격 강도가 저하되었다. 이를 방지하기 위한 첨가제가 연구되었는데 HDPE에는 에틸렌비닐알코올(EVA)을 첨가제로 5%정도 첨가하는 것이 효과적인 것으로 나타났다. PP의 경우에는 Maleic anhydride 변성 PP를 첨가하면 내충격강도의 저하가 축소되었다. LDPE, HDPE, PP, 폴리스티렌 및 ABS가 섞여있는 혼합 폐플라스틱에 대해서도 적니가 Filler로서 사용 가능한 것으로 나타났는데 이때는 성분간의 비상용성으로 인하여 기계적 물성이 매우 낮았다. 역시 첨가제로서 에틸렌프로필렌 고무(EPR) 및 스티렌부타디엔 블록공중합체(SBS)를 혼합할 경우 좋은 물성을 가지는 적니 혼합 플라스틱을 얻을 수 있었다.

• 한국CDE학회논문집
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• 제10권6호
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• pp.444-454
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• 2005

Recently, the requirements of multi-resolution models of a solid model, which represent an object at multiple levels of feature detail, are increasing for engineering tasks such as analysis, network-based collaborative design, and virtual prototyping and manufacturing. The research on this area has focused on several topics: topological frameworks for representing multi-resolution solid models, criteria for the level of detail (LOD), and generation of valid models after rearrangement of features. As a solution to the feature rearrangement problem, the new concept of the effective zone of a feature is introduced in the former part of the paper. In this paper, we propose a feature-based non-manifold modeling system to provide multi-resolution models of a feature-based solid or non-manifold model on the basis of the effective feature zones. To facilitate the implementation, we introduce the class of the multi-resolution feature whose attributes contain all necessary information to build a multi-resolution solid model and extract LOD models from it. In addition, two methods are introduced to accelerate the extraction of LOD models from the multi-resolution modeling database: the one is using an NMT model, known as a merged set, to represent multi-resolution models, and the other is storing differences between adjacent LOD models to accelerate the transition to the other LOD. We also suggest the volume of the feature, regardless of feature type, as a criterion for the LOD. This criterion can be used in a wide range of applications, since there is no distinction between additive and subtractive features unlike the previous method.

• 한국재료학회지
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• 제25권1호
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• pp.21-26
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• 2015

CMP(Chemical Mechanical Polishing) Processes have been used to improve the planarization of the wafers in the semiconductor manufacturing industry. Polishing performance of CMP Process is determined by the chemical reaction of the liquid sol containing abrasive, pressure of the head portion and rotational speed of the polishing pad. However, frictional heat generated during the CMP process causes agglomeration of the particles and the liquidity degradation, resulting in a non-uniform of surface roughness and surface scratch. To overcome this chronic problem, herein, we introduced NaCl salt as an additive into silica sol for elimination the generation of frictional heat. The added NaCl reduced the zata potential of silica sol and increased the contact surface of silica particles onto the sapphire wafer, resulting in increase of the removal rate up to 17 %. Additionally, it seems that the silica particles adsorbed on the polishing pad decreased the contact area between the sapphire water and polishing pad, which suppressed the generation of frictional heat.

• 한국도로학회논문집
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• 제12권4호
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• pp.87-92
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• 2010

본 연구에서는 산업부산물인 폐 EPDM을 50mesh 이하로 제조한 미세분말 형태의 R-EPDM(Recycling EPDM)을 주성분으로 아스팔트와 안정성을 높이기 위한 첨가제인 분산제와 유화제 및 폴리머 계통의 유동성 향상제를 혼합한 R-EPDM 개질아스팔트 혼합물의 실내 물성 평가를 수행하였다. R-EPDM 개질아스팔트 바인더의 특성을 파악하기 위해 슈퍼패이브 시험법을 이용하여 바인더의 PG(Performance Grade)등급을 분류하였으며, 선회다짐기를 사용한 R-EPDM 개질아스팔트 혼합물의 배합설계를 통하여 최적아스팔트(OAC) 함량을 결정하였다. OAC로 제작된 R-EPDM 개질아스팔트 혼합물의 소성변형 및 동결융해 저항성을 평가하기 위하여 반복주행시험과 수분민감성시험을 수행하였으며, R-EPDM 개질아스팔트 혼합물의 소성변형 및 수분민감성에 대한 저항성이 일반아스팔트(AP-5) 혼합물보다 우수함을 알 수 있었다.

• 대한방사선기술학회지:방사선기술과학
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• 제41권1호
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• pp.61-66
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• 2018

The recent 3D printing technology is used in various medical, manufacturing, and education fields and is more efficient in terms of production process, time, and cost than existing production. Especially in fracture surgery, interest and research have been focused on improving accuracy, shortening of operation time and recovery time, and reducing reoperation. However, because of the financial and technical problems of the 3D printer and the file conversion program, the 3D printing is made directly at the hospital, and it is not generally used for diagnosis of fracture and surgical research. In this study, to solve those problems, clavicle CT imaging was switched into Osirix Open Source DICOM Viewer, Stereolithography file conversion programs and commercial Terarecon 3D DICOM Viewer, file conversion programs, and then clavicle fracture model was directly made through 3D printer of fused filament fabrication wire additive processing method, and then the accuracy of the shape was compared and analyzed. Clavicle fracture models printed in two methods were blind-tested on clinicians of general hospitals' orthopedics and radiologic technicians with over 10 years of experiences, and then their analysis opinions of resolution reviews were analyzed. The result showed no difference. The 3D printing model with open source DICOM STL file conversion program used was applicable to clinical, so it is considered useful in precision diagnosis of fracture and operation plans.

• 폴리머
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• 제37권6호
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• pp.730-735
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• 2013

제지 공정에 있어서 지력 증강제로 사용되는 polyamide-epichlorohydrin(PAE)를 함유한 폴리비닐알코올(PVA)의 물성을 살펴보았다. PAE 첨가로 인하여 PVA의 용융과 결정화 열량이 감소될 뿐만 아니라 X-ray 결정 피크의 면적이 감소되는 것으로 보아 PAE에 의하여 PVA 가교가 진행됨을 알 수 있었다. 이러한 현상은 가수화도가 높은 PVA의 경우 더 두드러짐을 확인하였다. 하지만, 열처리에 의하여 PVA의 결정화가 일어나는 것으로 보아 PAE에 의한 PVA의 가교는 화학적 가교보다는 상대적으로 결합력이 약한 물리적 가교임을 알 수 있었다. PAE에 의한 PVA의 가교 및 결정화는 PVA의 열안정성, 기계적 강도를 증가시켜 이를 제지 공정의 지력 증강제로 사용할 경우, 종이의 건조 및 젖음 지력 향상에 효과가 있음을 알 수 있었다.

• 한국재료학회지
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• 제22권7호
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• pp.335-341
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• 2012

Recently, the demand for the miniaturization of printed circuit boards has been increasing, as electronic devices have been sharply downsized. Conventional multi-layered PCBs are limited in terms their use with higher packaging densities. Therefore, a build-up process has been adopted as a new multi-layered PCB manufacturing process. In this process, via-holes are used to connect each conductive layer. After the connection of the interlayers created by electro copper plating, the via-holes are filled with a conductive paste. In this study, a desmear treatment, electroless plating and electroplating were carried out to investigate the optimum processing conditions for Cu via filling on a PCB. The desmear treatment involved swelling, etching, reduction, and an acid dip. A seed layer was formed on the via surface by electroless Cu plating. For Cu via filling, the electroplating of Cu from an acid sulfate bath containing typical additives such as PEG(polyethylene glycol), chloride ions, bis-(3-sodiumsulfopropyl disulfide) (SPS), and Janus Green B(JGB) was carried out. The desmear treatment clearly removes laser drilling residue and improves the surface roughness, which is necessary to ensure good adhesion of the Cu. A homogeneous and thick Cu seed layer was deposited on the samples after the desmear treatment. The 2,2'-Dipyridyl additive significantly improves the seed layer quality. SPS, PEG, and JGB additives are necessary to ensure defect-free bottom-up super filling.