• 한국자동차공학회논문집
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• 제18권5호
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• pp.45-49
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• 2010

The automotive industry has shown a growing interest in tube hydroforming during the past years. The advantages of hydroforming (less thinning, a more efficient manufacturing process, etc.) can, for instance, be combined with the high strength of extra high strength steels, which are usually less formable, to produce structural automotive components which exhibit lower weight and improved service performance. Design and production of tubular components require knowledge about tube material and forming behavior during hydroforming and how the hydroforming operation itself should be controlled. These issues are studied analytically in the present paper. In this study, the whole process of rear sub-frame parts development by tube hydroforming using AA6061 material is presented. At the part design stage, it requires feasibility study and process design aided by CAE (Computer Aided Engineering) to confirm hydroformability in details. Effects of parameters such as internal pressure, axial feeding and geometry shape in automotive rear sub-frame by hydroforming process were carefully investigated. Overall possibility of hydroformable rear sub-frame parts could be examined by cross sectional analyses. Moreover, it is essential to ensure the formability of tube material on every forming step such as pre-bending and hydroforming. In addition, all the components of prototyping tool are designed and interference with press is examined from the point of geometry and thinning.

• Parasites, Hosts and Diseases
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• 제39권2호
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• pp.185-192
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• 2001

To evaluate the factors that determine the transmission level of vivax malaria using vectorial capacity, entomological surveys were conducted from .lune to August, 2000. From 6 nights of human-bait collection in Paju, the human biting rate (ma) was counted as 87.5 bites/man/night. The parity of Anopheles sinensis from human baiting collections fluctuated from 41% to 71% (average 48.8%) of which the rate gradually increased as time passed on: 35.2% in Jun. ; 55.0% in July; 66.2% in Aug. From this proportion of parous, we could estimate the probability of daily survival rate of An. sinensis to be 0.79 assumed with 3 days gonotrophic cycle and the expectancy of infective life through 11 days could be defined as 0.073. Blood meal analysis was performed using ELISA to determine the blood meal source. Only 0.8% of blood meals were from human hosts. We could conclude that An. sinensis is highly zoophilic (cow 61.8%) Malaria is highly unstable (stability index < 0.5) in this area. From these data, vectorial capacity VC) was determined to be 0.081. In spite of a high human biting rate (ma), malaria transmission potential is very low due to a low human blood index. Therefore, we could conclude that malaria transmission by An. sinensis is resulted by high population density, not by high transmission potential. For this reason, we need more effort to decrease vector population and vector-human contact to eradicate malaria in Korea.

• 대한간호학회지
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• 제41권4호
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• pp.451-459
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• 2011

Purpose: In this study the effects of breast massage on breast pain, breast-milk sodium, and newborn suckling in early postpartum mothers were investigated. Methods: The design was a non-synchronized nonequivalent control group pretest-post-test design. Sixty postpartum mothers who were admitted to a postpartum care center and had problems with breastfeeding were recruited. Of these mothers, 44 were assigned to the intervention group and received two 30-minute breast massages within 10 days of postpartum period. The others were assigned control group and received only routine care. Breast pain was measured using a numeric pain scale and number of times newborns suckled was observed throughout breastfeeding. Breast milk was self-collected to evaluate breast-milk sodium. Results: Mean age of postpartum mothers was 30 years old. Compared to the control group, women in the intervention group reported significant decreases in breast pain (p<.001), increases in number of times newborns suckled after the first and second massage (p<.001), and a decrease in breast-milk sodium after the first massage (p=.034). Conclusion: Breast massage may have effects on relieving breast pain, decreasing breast-milk sodium, and improving newborn suckling. Breast massage can be used to solve breast problems. Further research is needed to validate our findings.

• 부모자녀건강학회지
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• 제3권1호
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• pp.73-94
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• 2000

This study was designed to compare the education needs in LBW infant's mother at discharge and after one month at home for development of the educational program. The subjects of this study consisted of 61 mothers of LBW infant's at discharge and 51 mothers of LBW infant's after one month at home. They were selected by convenience from 3 general hospitals and 1 pediatric hospital in Seoul, Kangreung and Inchon. The data were collected during the period from January, 5 to March, 15, 2000. The Education Needs for LBW infant Care was measured by Questionnaire that has developed by researchers. The data were analized by descriptive statistics, non-paired t-test & ANOVA using SAS. The results of this study were as follows: 1) The educational need, of the mothers of LBW infant at discharge were higher than the mothers of LBW infant after one month at home(t=8.72, p=.00). 2) There were significant associations between the educational needs of the mothers of LBW infant after one month at home and numbers of children(F=3.61, p=0.03). 3) There were significant associations of the educational needs between the mothers of LBW infant at discharge and the mothers of LBW infant after one month at home in categories and items. (1) There were significant associations by categories such as Infant care(t=8.34, p=.00), feeding(t=6.71, p=.00), unusual behavior (t=6.54, p=.00). Management disorder (t=8.67, p=.00), attachment between parents and infant(t=5.19, p=.00) and environment (t=6.14, p=.00). (2) There were two items that represented the highest educational needs in all items. That were "How about we can do when infant has a breathing disorder" and "How about we can do when infant has a seizure". These two items included Management of disorder category. In Conclusion, when the nurse teaching the method of infant care to mother, educational contents must be included about Management of disorder emphatically.

• Carbon letters
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• 제12권1호
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• pp.31-38
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• 2011

This study experimentally investigated dicyclohexylammonium 2-cyanoacrylate (CA) as a potential comonomer for polyacrylonitrile (PAN) based carbon fiber precursors. The P(AN-CA) copolymers with different CA contents (0.19-0.78 mol% in the feed) were polymerized using solution polymerization with 2,2-azobis(isobutyronitrile) as an initiator. The chemical structure and composition of P(AN-CA) copolymers were determined by proton nuclear magnetic resonance and elemental analysis, and the copolymer composition was similar to the feeding ratio of the monomers. The effects of CA comonomer on the thermal properties of its copolymers were characterized differential scanning calorimetry (DSC) in nitrogen and air atmospheres. The DSC curves of P(AN-CA) under nitrogen atmosphere indicated that the initiation temperature for cyclization of nitrile groups was reduced to around $235^{\circ}C$. The heat release and the activation energy for cyclization reactions were decreased in comparison with those of PAN homopolymers. On the other hand, under air atmosphere, the P(AN-CA) with 0.78 mol% CA content showed that the initiation temperature of cyclization was significantly lowered to $160.1^{\circ}C$. The activation energy value showed 116 kJ/mol, that was smaller than that of the copolymers with 0.82 mol% of itaconic acids. The thermal stability of P(AN-CA), evidenced by thermogravimetric analyses in air atmosphere, was found higher than PAN homopolymer and similar to P(AN-IA) copolymers. Therefore, this study successfully demonstrated the great potential of P(AN-CA) copolymers as carbon fiber precursors, taking advantages of the temperature-lowering effects of CA comonomers and higher thermal stability of the CA copolymers for the stabilizing processes.

• Asian-Australasian Journal of Animal Sciences
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• 제16권6호
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• pp.903-909
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• 2003

For the last two decades, energy utilization of growing chicks has been studied more and more. This paper focuses on the energy utilization estimated by the metabolizable energy (ME) values and the efficiency at which ME is used for growth of chicks under various nutritional environment. Degree of saturation of dietary fats is responsible for nitrogen-corrected apparent metabolizable energy (AMEn) of fats. The effect of dietary fat sources on heat production depends on the kind of unsaturated fatty acids as well as the degree of saturation. Medium chain triglyceride shows lower AME and net energy than long chain triglyceride. Phytase as feed additives increases the AME values of the diet along with improvement of the phosphorous utilization. Ostriches have higher ability to metabolize the energy of fiber-rich foodstuffs than fowls. Their higher ability seems to be associated with fermentation of fiber in the hindgut. Proportions of macronutrients in the diets have influenced not only the gain of body protein and energy but also the oxidative phosphorylation of the chicken liver. Essential amino acids deficiency reduces ME/GE (energy metabolizability) little, if any. Growing chicks respond to a deficiency of single essential amino acids with the reduction of energy retained as protein and increased energy retained as fat. Thus, energy retention is proportional to ME intake despite deficiency, and efficiency of ME utilization is not affected by deficiency of amino acids. Effect of oral administration of clenbuterol, a beta-adrenergic agonist, on the utilization of ME varies with the dose of the agents. Although the heat production related to eating behavior has been estimated less than 5% of ME, tube-feeding diets decreases HI by about 30%.

• The Korean Journal of Physiology and Pharmacology
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• 제4권4호
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• pp.275-281
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• 2000

Cholecystokinin (CCK) is a gastrointestinal hormone which plays an important role in satiety and gastric motility. It is also widely distributed throughout the central nervous system, where it appears to be involved in the central control of anxiety, feeding behavior and nociception. Two distinct CCK receptor types, $CCK_A$ and $CCK_B,$ have been found in the brain. Both CCK receptors coexist in the rat nucleus tractus solitarius (NTS), which is the primary center for the coordination of peripheral and central activities related to gastrointestinal, cardiovascular and respiratory functions. In order to study ionic actions of CCK on each type of receptor, we investigated the effects of CCK-8S on neurons located in the NTS of the rat using whole-cell patch-clamp recordings in brainstem slices. Application of CCK-8S, under current clamp, produced a membrane depolarization accompanied by action potential firing. This CCK-evoked excitation was dose-dependent $(10\;nM{\sim}10\;{\mu}M)$ and observed in more than 60% of NTS neurons. Under voltage clamp conditions, CCK-8S induced an inward current with a notably increased spontaneous excitatory synaptic activity. However, CCK-8S did not significantly change the amplitude of pharmacologically isolated and evoked EPSP(C)s. Using selective $CCK_A$ and $CCK_B$ receptor antagonists, we observed two different effects of CCK-8S, which suggest $CCK_A$ receptor-mediated inhibitory and $CCK_B$ receptor-mediated excitatory effects in the NTS. These results may help to explain the ability of CCK to modulate gastrointestinal and other reflex systems in the NTS.

• Journal of Nutrition and Health
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• 제33권1호
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• pp.42-48
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• 2000

The study was designed to observe the effect of complete listing for 10 days on body fatness, serum leptin level and lipid profile in thirty women who were admitted to fasting Clinical Program in Kyung-Hee Oriental Medical Center. Most of the subjects had food habits of over-eating and preferred oily foods which was correlated to the increase of body weight and BMI during realimentation. Average loss of body weight was 7.98kg and waist-hip ratio was significantly decreased during fasting. Body weight showed significant positive correlation with body fat(r=0.8182), lean body mass(r=0.7797) and total body water(r=0.7563). Body fat was gradually reduced after 9 days fasting, but lean body mass was not diminished any more after 7 days luring. Serum leptin level was significantly decreased after luring and re-feeding. The leptin showed significant positive correlation with body weight(r=0.9324), body mass index(r=0.8279) and body fat(r=0.8376). The levels of serum total cholesterol and LDL-C were significantly increased but HDL-C level was significantly decreased after fasting which increased could be harmful for persons with hypercholesterolemia. VLDL-C and triglyceride levels were not significantly decreased after fasting. Serum total free fatty acid level was significantly increased after fasting. These data suggest that the best way of maintaining the reduced body weight was to carry out the modification of food habits and behavior in daily lift. It could not be recommended to repeat often complete luting for reduction of body weight. (Korean J Nutrition 33(1) : 42-48, 2000)

• 한국양식학회지
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• 제11권3호
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• pp.401-419
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• 1998

제주도의 8개지점(함덕, 온평, 위미, 법환, 화순, 대포, 한림, 외도)에서 해조장형성과 조식성의 대표적이 동물인 성게류(보라성게,Anthocidaris crassispina와 말똥성게 Hemicentrotus pulcherrimus)의 섭이형태에 대하여 연구하였다. 각 조사지점의 해조류 생체량이 조사되었으며, 성게류의 장내용물과 생물학적 측정치에 관련된 해조류 군락의 양적분포와 우점도가 조사되었다. 결론적으로 대포지점의 조사지점이 해조상으로는 가장 우세함에도 불구하고 성게의 생물학적인 특성인 체고, 체장, 체중 그리고 생식소 지수와의 관련이 없었다. 이는 성게류들이 조류의 풍도에만 의존하는 곳이 아니고 다른 먹이물질을 섭이함을 뜻한다. 성게의 음식물 선호도를 위해 섭이된 장내용물을 조사한 결과 부착성 조류와 유조(drifted algae) 및 다양한 동물들 (해면, 태충류, 갑각류 및 미확인된 캡슐에 싸인 알 등)과 펄이나 모래와 같은 저질들이 먹이물질로 조사되었다. 섭이된 음식물의 상대적인 양으로 볼 때, 해조류의 섭식률은 낮은 것으로 밝혀졌으며, 이로서 성게가 조장형성이나 갯녹음 현상을 일으키는 해조류의 우요 섭식자가 아닐 것으로 추정할 수 있다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.158-161
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• 2003

Recently, the evolution in production techniques (e.g. high-speed milling), the complex shapes involved in modem production design, and the ever increasing pressure for higher productivity demand a drastic improvement of the dynamic behavior of the machine tool axes used in production machinery. And also machine tools of multi functional and minimized parts are increasingly required as demand of higher accurate in some fields such as electronic and optical components etc. The accuracy and the productivity of machined parts are natural to depend on the linear system of machine tools. The complex workpiece surfaces encountered in present-day products and generated by CAD systems are to be transformed into tool paths for machine tools. The more complex these tool paths and the higher the speed requirements, the higher the acceleration requirements are needed to the machine tool axes and the motion control system, and the more difficult it is to meet the requirements. The traditional indirect drive design for high speed machine tools, which consists of a rotary motor with a ball-screw transmission to the slide, is limited in speed, acceleration, and accuracy. The direct drive design of machine tool axes. which is based on linear motors and which recently appeared on the market. is a viable candidate to meet the ever increasing demands, because of these advantages such as no backlash, less friction, no mechanical limitations on acceleration and velocity and mechanical simplicity. Therefore performance tests were carried out to machine tool axes based on linear motor. Especially, dynamic characteristics were investigated through circular test.