• 한국지형공간정보학회:학술대회논문집
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• 2004.10a
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• pp.5-10
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• 2004

The purpose of this research is to measure a gravitational attraction about urban pulbic service facilities and to evaluate the location of public service facilities. It is important in that these facilities should provide more inexpensive and convenience public service to users. To do this, the GIS's spatial analysis and gravity model were used to analyze the efficiency of the public facilities. The gravity model was conducted as the main analysis method, and another model for this analysis was the discrete model. The gravity model is originally to anticipate migration flows, traffic flows and other types of movements so that this model compares the gravitational attraction between places. The discrete model is to find the optimal location and to evaluate a location of facility regarding urban areas as the combination of node and link. In this research, these two models were adopted to compare and analyze location of Mapo-Gu Office. The results of this research indicated that the locational evaluation of urban public service facilities discovered the appropriateness of those facilities, and the public facilities was necessary to displace to other site.

• KSBB Journal
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• v.20 no.3
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• pp.238-243
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• 2005

Succinic acid has recently been drawing much interest as a raw material for biodegradable polymer. In this study acetic acid was removed by reactive extraction with various amines dissolved in various diluents. Distribution coefficients were determined as the kind of amines, diluents, and pHs of continuous phase. The extraction capacity increased with the polarity of diluent and the decrease of pH from the artificial binary solution. Based on the different extractability for succinic acid and acetic acid from the artificial binary solution, the removal of acetic acid from fermentation broth was investigated using various amines and diluents. In addition, the extractability and selectivity of CLA for succinic acid and acetic acid from fermentation broth were higher than that of straight solvent extraction.

• Journal of Gastric Cancer
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• v.15 no.2
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• pp.105-112
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• 2015

Purpose: Intracorporeal anastomosis is the most difficult procedure during pure single-incision distal gastrectomy (SIDG) that affects its generalization. We introduced unaided delta-shaped anastomosis (uDelta), a novel anastomosis technique, for gastroduodenostomy after pure SIDG, and compared the results with those of previously reported Roux-en-Y anastomosis (RY). Materials and Methods: Between March 2014 and March 2015, SIDG with D1+ lymph node dissection was performed for early gastric cancer through a 2.5-cm transumbilical incision without any additional port. uDelta was performed by the operator alone, without any intracorporeal assistance. Results: uDelta was performed on 11 patents, and uncut RY was performed on 5-patients without open or multiport conversion. R0 resection was performed in all cases. No significant differences were observed in mean age and body mass index between patients who underwent uDelta or RY. Mean operation times were $214.5{\pm}36.2$ minutes for uDelta and $240.8{\pm}65.9$ minutes for RY, which was not significantly different. Reconstruction time for uDelta was shorter than that for RY, with marginal statistical significance ($26.1{\pm}8.3$ minutes vs. $38.0{\pm}9.1$ minutes, P=0.05). There were no intraoperative transfusions, 30-day mortality, or anastomosis-related complications in either group. Average length of hospital stay was $8.2{\pm}1.9$ days in the uDelta group and $7.2{\pm}0.8$ days in the RY group (P=0.320). Conclusions: After carefully considering indications, uDelta can be a feasible and can be a reproducible reconstruction method after SIDG in early gastric cancer.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.7
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• pp.950-956
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• 2017

Objective: Effects of newly isolated Lactobacillus plantarum on the fermentation and chemical composition of fresh rice straw silage was evaluated in this study. Methods: Lactic acid bacteria (LAB) from good crop silage were screened by growing them in MRS broth and a minimal medium with low carbohydrate content. Selected LAB (LAB 1821) were Gram-positive, rods, catalase negative, and were identified to be Lactobacillus plantarum based on their biochemical characteristics and a 16S rRNA analysis. Fresh rice straw was ensiled with two isolated LAB (1821 and 1841), two commercial inoculants (HM/F and P1132) and no additive as a control. Results: After 2 months of storage at ambient temperature, rice straw silages treated with additives were well-preserved, the pH values and butyric and acetic acid contents were lower, and the lactic acid content and lactic/acetic acid ratio were higher than those in the control (p<0.05). Acidity (pH) was lowest, and lactic acid highest, in 1821-treated silage (p<0.05). The $NH_3-N$ content decreased significantly in inoculant-treated silage (p<0.05) and the $NH_3-N$ content in 1821-treated silage was lowest among the treatments. The dry matter (DM) content of the control silage was lower than that of fresh rice straw (p<0.05), while that of the 1841- and p1174-inoculant-treated silages was significantly higher than that of HM/F-treated silage. Microbial additives did not have any significant (p>0.05) effect on acid detergent fiber or neutral detergent fiber contents. Crude protein (CP) content and in vitro DM digestibility (IVDMD) increased after inoculation of LAB 1821 (p<0.05). Conclusion: LAB 1821 increased the CP, IVDMD, lactic acid content and ratio of lactic acid to acetic acid in rice straw silage and decreased the pH, acetic acid, $NH_3-N$, and butyric acid contents. Therefore, adding LAB 1821 improved the fermentation quality and feed value of rice straw silage.

• Polymer(Korea)
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• v.30 no.6
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• pp.519-524
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• 2006

Poly(4-vinyl pyridine) (PVP) and its copolymers, poly(4-vinyl pvridine- co-acrylamide) and poly(4-vinyl pyridine-co-allylamine), were synthesized and evaluated for application to organic solder-ability preservatives (OSP). The copolymers were synthesized by radical polymerization of vinyl pyridine in the presence of acrylamide or allylamine as a comonomer. Various kinds of polymers with different chemical composition were synthesized by varying the feed ratio of monomers and their low $M_w$ polymers can be obtained by adding 2-mercaptoethanol as a chain transfer agent during poly-merization. All the polymers showed good adhesion properties on Cu pad when they were spin-coated. Especially, allylamine -containing copolymers showed both good adhesion and solubility properties. Also, they exhibited better thermal stability than PVP homopolymer and such thermal properties were changed depending on the chemical composition and their $M_w$, which were evidenced by the measurement of oxygen induced temperature (OIT). From the OIT measurement, poly(4-vinyl pyridine- co-allylamine) was thermally stable up to $230^{\circ}C$ for 70 min in the 100% oxygen environment. As a result, allylamine-containing copolymers can be considered as a promising OSP coating material that has excellent thermal and adhesive properties applicable to the present microelectronic package processes.

• Imaging Science in Dentistry
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• v.40 no.2
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• pp.69-74
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• 2010

Purpose : The research was performed to predict the three dimensional relationship between the impacted mesiodens and the maxillary central incisors and the proximity with the anatomic structures by comparing their panoramic images with the CT images. Materials and Methods : Among the patients visiting Seoul National University Dental Hospital from April 2003 to July 2007, those with mesiodens were selected (154 mesiodens of 120 patients). The numbers, shapes, orientation and positional relationship of mesiodens with maxillary central incisors were investigated in the panoramic images. The proximity with the anatomical structures and complications were investigated in the CT images as well. Results : The sex ratio (M : F) was 2.28 : 1 and the mean number of mesiodens per one patient was 1.28. Conical shape was 84.4% and inverted orientation was 51.9%. There were more cases of anatomical structures encroachment, especially on the nasal floor and nasopalatine duct, when the mesiodens was not superimposed with the central incisor. There were, however, many cases of the nasopalatine duct encroachment when the mesiodens was superimpoised with the apical 1/3 of central incisor (52.6%). Delayed eruption (55.6%), crown rotation (66.7%) and crown resorption (100%) were observed when the mesiodens was superimposed with the crown of the central incisor. Conclusion : It is possible to predict three dimensional relationship between the impacted mesiodens and the maxillary central incisors in the panoramic images, but more details should be confirmed by the CT images when necessary.

• Journal of the Korean Magnetics Society
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• v.16 no.6
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• pp.300-304
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• 2006

The varied heating temperatures were used for magnetic core materials, which nano sized ${\alpha}-Fe$ crystalline was created in nanocrystalline Fe-Si-B-Nb-Cu materials, with hish permeability and low power loss. The highest permeability and lowest power loss were obtained to the specimen heat-treated at $510^{\circ}C$. The signal transmission characteristics of inductive coupler, which was manufactured by using the magnetic core materials prepared in this study, at low frequency range, was influenced strongly by magnetic property of magnetic core materials as this result is corresponding to the permeability as a function of heat treatment temperature, as well, it was improved by impedance matching at high frequency range. Over $500{\mu}m$ of air gap in coupler is required to maintain the magnetic properties without magnetic saturation on the subterranean line transferred hish current of 300 A. The inductive coupler for PLC, which has an attenuation characteristics of less than 5dB, was manufactured using nano-crystalline magnetic core materials through the above mentioned research results.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.168-173
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• 2000

Anticariogenic activity of the unripe apple extract was studied by observing the inhibitory effects on GTase(glucosyltransferase) activity, cell adherence and acid production of Streptococcus mutans. Among the four S. mutans strains, S. mutans MT 8148 had the highest water-insoluble glucan forming activity. (+)-Catechin and tannic acid, the major components of the unripe apple polyphenols inhibited GTase activity by 60% at 1 mg/ml and 90% at 5 mg/ml. Tannic acid and unripe apple extract inhibited adherence ability of S. mutans by 50% and 30%, respectively. But the acid production of S. mutans was not influenced by the polyphenols. Disc diffusion test showed that the polyphenols have no antimicrobial activity against S. mutans, which indicates that the inhibition of GTase activity and cell adherence were not resulted from the cell growth inhibition. Our results convinced the possible application of the unripe apple extract as the anticariogenic food additives.

• Journal of the Korean Institute of Gas
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• v.20 no.6
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• pp.50-57
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• 2016

Pipeline is one of the most abundant components in petrochemical plant. It plays a critical role in transporting fluids. Some pipelines are thermally insulated by wrapping them with insulating materials to prevent the loss of energy. However, when corrosion begins under insulation, it cannot be easily seen without unwrapping the cover, and thus corrossion should be detected using a non-destructive ways such as ultrasound guided wave. In this paper, the piping where the CUI (Corrosion Under Insulation) which occurs in the insulation parts guided waves effectively the optimum condition which is theoretical for selected guided waves phase velocity dispersion curve and wave-structure. The results of this study are expected to be directly utilized for onsite inspection of pipeline's CUI in many petrochemical plants.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.228-228
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• 2007

전력선 통신용 비접촉식 커플러는 고속형(2~30 MHz)과 저속형(100~450KHz)으로 나누어 볼 수 있는데, 고속형은 현재 국내에서 독자적으로 개발되어 다양한 모델이 적용되고 있는 상황이지만, 저속형은 시작품수준으로 제조되어 있으나 신호전송 특성의 향상절구가 필요한 상황이다. 전력선 통신용 커플러는 전력선 또는 모뎀으로 통신신호를 전달하는 기능을 하는 것으로서, 전력선 통신을 위한 핵심부품이다. 따라서 본 연구에서는 100~450 KHz 대역에서 사용 가능한 저속형 비접촉식 커플러를 제조하기 위해, 권선조건, 대전류형 자심재료의 모의 해석, 노이즈 필터조건, 임피던스 매칭, 하우징방법 등의 각 공정 변수를 확립하고자 하였다. 자심재료의 모의해석에서 자심재료의 높이와 전력선 도체 단면적 변화는 자심재료의 전류포화특성에 영향을 미치지 않으며, 유효길이와 에어-갭 크기가 증가할수록 전류포화특성은 향상되는데, 자심재료의 내경이 64 mm일 때 자심재료의 폭((외경-내경)/2)은 15 mm 이상이어야 하고, 에어-갭은 약 $600\;{\mu}m$ 정도의 에어-갭을 형성시켜야함을 확인할 수 있었다. 또한 저속용 비접촉식 커플러 제조조건 실험에서 내경${\times}$외경${\times}$높이가 $64{\times}94{\times}140mm$인 자심재료를 이용하여 권선 수와 에어-갭을 각각 3회, $400{\sim}600\;{\mu}m$ 삽입했을 때, 가장 우수한 특성을 나타내었다. 그리고 저역 통과 필터를 출력부에 내장하여 통신신호 이외의 노이즈를 제거할 수 있었다. 본 연구에서 제조된 300 A급 지중선용 저속형 비접촉식 커플러는 내경${\times}$외경${\times}$높이가 $58{\times}1144{\times}158mm$이고, 100~450 KHz 통신대역에서 약$7{\pm}2dB$의 삽입손실을 나타내었다.