• 한국공작기계학회논문집
• /
• 제13권4호
• /
• pp.106-112
• /
• 2004

In particle or short-fiber reinforced composites, cracking or debonding of the reinforcements cause a significant damage mode because the damaged reinforcements lose load carrying capacity. The average stress in the inhomogeneity represents its load carrying capacity, and the difference between the average stresses of the intact and broken inhomogeneities indicates the loss of load carrying capacity due to cracking damage. The composite in damage process contains intact and broken reinforcements in a matrix. An incremental constitutive relation of discontinuously-reinforced composites including the progressive cracking damage of the reinforcements have been developed based on the Eshelby's equivalent inclusion method and Mori-Tanaka's mean field concept. Influence of the cracking damage on the stress-strain response of the composites is demonstrated.

• Journal of Mechanical Science and Technology
• /
• 제19권7호
• /
• pp.1460-1468
• /
• 2005

Two possible shape memory processes, austenite to detwinned martensite transformation and twinned martensite to detwinned martensite transformation of a shape memory alloy have been modeled and examined. Eshelby's equivalent inclusion method with Mori-Tanaka's mean field theory is used for modeling of the shape memory processes of TiNi shape memory alloy reinforced aluminum matrix composite. The shape memory amount of shape memory alloy, plastic strain and residual stress in the matrix are computed and compared for the two processes. It is shown that the shape memory amount shows differences in a small prestrain region, but the plastic strain and the residual stress in the matrix show differences in the whole prestrain region. The shape memory process with initially martensitic state of the shape memory alloy would be favorable to the increase in the yield stress of the composite owing to the large compressive residual stress and plastic strain in the matrix.

• 여성건강간호학회지
• /
• 제14권3호
• /
• pp.196-204
• /
• 2008

Purpose: This study aimed to examine the effects abdominal breathing on anxiety and length of labor time in primipara women. Method: It was a quasi-experimental design with a non-equivalent comparison group, performed from October 11 to December 4, 2007. Thirty-six subjects who received pitocin and met the inclusion criteria were chosen by convenience sampling from the labor room of Y hospital located in Seoul. The intervention of abdominal breathing was 'four seconds of inhale, six seconds of exhale breathing method.' The abdominal breathing was carried out 30 times each when the uterine cervix was dilated $3{\sim}4cm$ and $5{\sim}6cm$. Psychological anxiety was measured by VAS-A before and after the cervix dilatation to $3{\sim}4cm$ and $5{\sim}6cm$. Result: Anxiety scores of the experimental was found lower than that of the control group at $3{\sim}4cm$(z=-3.05, p=.00) and $5{\sim}6cm$(z=-2.04, p=.04) of cervix dilatation. However, the abdominal breathing was not effective to the length of labor from the active phase thru full dilatation, though there was 56 minutes of difference between the two groups. Conclusion: Carrying out the abdominal breathing 30 times at two time points was effective in decreasing anxiety level during labor. Further study is suggested to examine the effects of abdominal breathing on labor time, fetal heart rate, and uterine contraction.

• Structural Engineering and Mechanics
• /
• 제33권4호
• /
• pp.429-446
• /
• 2009

Three-scale homogenization procedure is proposed in this paper to provide estimates of the effective thermal conductivities of porous carbon-carbon textile composites. On each scale - the level of fiber tow (micro-scale), the level of yarns (meso-scale) and the level of laminate (macro-scale) - a two step homogenization procedure based on the Mori-Tanaka averaging scheme is adopted. This involves evaluation of the effective properties first in the absence of pores. In the next step, an ellipsoidal pore is introduced into a new, generally orthotropic, matrix to make provision for the presence of crimp voids and transverse and delamination cracks resulting from the thermal transformation of a polymeric precursor into the carbon matrix. Other sources of imperfections also attributed to the manufacturing processes, including non-uniform texture of the reinforcements, are taken into consideration through the histograms of inclination angles measured along the fiber tow path together with a particular shape of the equivalent ellipsoidal inclusion proposed already in Sko ek (1998). The analysis shows that a reasonable agreement of the numerical predictions with experimental measurements can be achieved.

• Journal of Pharmaceutical Investigation
• /
• 제27권4호
• /
• pp.295-301
• /
• 1997

Nitrendipine, a slightly soluble calcium channel blocking agent forms a solid dispersion system with $hydroxypropyl-{\beta}-cyclodextrin$, which exhibits better dissolution characteristics than the uncomplexed drug. The dissolution rate of nitrendipine was markedly increased in solid dispersion system in pharmacopeial disintegration media at pH 1.2 and pH 6.8. Four different dosage forms of nitrendipine were administered to rats: (a) nitrendipine in the solution of PEG 400; (b) nitrendipine solid dispersion system with $hydroxypropyl-{\beta}-cyclodextrin$ in a molar ratio of 1:2 by solvent evaporation method and administered in capsule form; (c) physical mixture of nitrendipine with $hydroxypropyl-{\beta}-cyclodextrin$ in a molar ratio of 1:2 and administered in capsule form; (d) nitrendipine alone administered in capsule form. Relative bioavailability after the oral administration of various dosage forms to rats with a dose of 10 mg/kg equivalent to nitrendipine was compared with that of nitrendipine in the solution of PEG 400. The AUC of solid dispersion was significantly bigger than that of nitrendipine powder. $T_{max}$ of solid dispersion was significantly shorter and $C_{max}$ was higher than that of nitrendipine powder. These results indicate that the bioavailability of nitrendipine could be improved markedly by inclusion complexation. An interesting correlation also appears to exist between the in vitro dissolution data and the area under the plasma concentration-time curves.

• Asian-Australasian Journal of Animal Sciences
• /
• 제14권11호
• /
• pp.1605-1609
• /
• 2001

A total of 252, 50 week-old Isa-brown laying hens were randomly allotted to 7 groups of 3 replicates. Mustard meal (MM) which is a by-product from mustard processing plant, was dried under the sun or in a gas heated pan. It contained on DM basis 30-32% CP, 19-22% EE and 12-13% CF. The meal from either drying method was incorporated into the diets at 0, 10, 20 and 30% which was equivalent to the substitution levels for soybean meal at 0, 31, 63 and 94%, respectively. All birds were individually kept in battery cages where feed and water were freely accessed throughout 84 days experimental period. It was found that egg production, feed intake, body weight gain and egg weight significantly decreased with the increased MM level. The inclusion of 20% MM did not show a significant difference in egg production and quality from the control, but produced 6-8% lower egg production. Feed intake was linearly decreased with the MM levels, except the 10% sun dried MM group. Fat deposition of the birds fed MM diets significantly decreased, while kidney weight increased when compared with the control group. However, the weight of thyroid glands and spleen trended to be heavier in the MM groups, but this was not significantly different among dietary treatments. It was concluded, MM from both drying methods could be incorporated in laying hen diets at the level of 10% without any adverse effect.

• 대한전자공학회논문지TC
• /
• 제44권12호
• /
• pp.8-15
• /
• 2007

본 논문에서는 기존의 Right/left-handed 전송선(RLH-TL)에 집중 직렬 캐패시터와 병렬 인덕터 구현으로 발생하는 방사 효과를 포함하여 단위 셀을 모델링한다. 방사 효과가 고려된 RLH-TL 단위셀의 등가 회로를 제공하고 갭 커패시터와 션트 인터터에서의 방사율에 따른 Bloch 임피던스와 복소 전파상수를 해석한다. 두 개의 방사율이 같을 때 RLH-TL의 Block 임피던스는 RH-TL의 특성임피던스와 같아짐을 보인다. 게다가, 주어진 주파수에서 특정한 위상 변화를 위한 단위 셀의 설계 공식을 유도하여 제공한다. 마지막으로, 안테나 응용을 위해 RLH-TL에서 다양한 방법으로 방사효과를 control할 수 있는 설계 공식을 제공한다.

• 한국임상약학회지
• /
• 제22권2호
• /
• pp.131-136
• /
• 2012

Objective: This study evaluated and compared the adherence to the CONSORT for quality of reports on the randomized controlled trials (RCT) abstracts by four major Korean Science Citation Index (SCI) journals and The New England Journal of Medicine (NEJM). Methods: A descriptive analysis of published RCT abstracts in Korean SCI journals and NEJM from 2007/01 to 2011/06 was conducted by two reviewers, independently extracting data from a PubMed search. A modification of CONSORT for abstract was used including 16 checklist items. Reporting of checklist items for individual group was conducted to compare adherence patterns between two groups. Results: We identified the potential 57 RCT abstracts from Korean SCI and 50 from NEJM meeting our inclusion criteria; among them, three abstracts from Korean SCI and one from NEJM were excluded. Among total 16 checklist items based on CONSORT statement, Korean SCI journals and NEJM were statistically equivalent in 4 items; Korean journals were better in three items and NEJM were in nine. The methodological quality domains were inadequately reported in both journals: allocation concealment about 1.9% and 4.0%, and blinding 44.4% and 40.8%. In general, The CONSORT adherence of NEJM was better than that of Korean SCI in the method and result domain (p < 0.0001). Conclusions: The quality of NEJM reporting of RCT abstracts was better than that of Korean SCI, in general. This study on adherence of RCT reports from Korean SCI journals and NEJM abstracts to the CONSORT statement reveals that there is a need for improvement, especially Korean SCI. Further investigation on the quality of RCT reports and ways to improve reporting quality is required.

• Composites Research
• /
• 제18권5호
• /
• pp.21-26
• /
• 2005

본 연구에서는 복합재의 등가 물성치를 예측하는 방법중 하나인 Mori-Tanaka의 평균장이론이 결합된 Eshelby 이론의 적용한계에 대해 유한요소해석을 통하여 강화재의 크기와 배치 측면에서 고찰하였다. 모델 복합재로 일정 체적비의 강화재를 포함하는 2차원 평판 복합재를 사용하였으며, 강화재의 크기를 변화시키고 또한 강화재를 규칙적 및 불규칙적으로 배치하였다. 이 복합재에 유한요소해석을 적용하여 수치적으로 복합재의 등가 물성치를 구하였으며, 수치해석결과를 Eshelby 이론으로 구한 등가 물성치와 비교하였다. Eshelby 이론으로 예측되는 복합재의 등가 물성치는 시편의 크기에 비해 강화재의 크기가 0.03이하가 되면 강화재의 배치와 관계없이 유한요소해석으로 구한 복합재의 평균 영계수와는 잘 일치하나, 평균 프와송비는 약 $20\%$의 차이를 보였다.

• 보건교육건강증진학회지
• /
• 제16권1호
• /
• pp.137-148
• /
• 1999

The necessity of school health promoting projects is well known to many researchers, however, there is a lack of research on the development of strategies for school health programs and the evaluation of the effectiveness of the programs. The results of our previous study in 1996 identified poor eyesight as one of the several health problems among elementary school children in urban areas. The main objective of this study is to develop, implement, and evaluate vision care for elementary school children. The research method utilized a quasi experimental design using non-equivalent group, pre-post comparison. The sample consisted of all second grade children in two elementary schools in Kyung-giProvince. In order to prevent a contamination effect of the vision care program, one school was selected as a control and the other school was selected as a treatment group. The experimental school had 467 children and the control school had 402 children. The visual acuity of children in both group was measured and a survey questionnaire was sent out to parents on the knowledge, attitude, and behavior related to vision care before the program was implemented. The children of the experimental school received the following programs; separate education on proper nutrition and care of eyesight for children and parents, daily eye exercises using video tape, and an essay and poster contest on healthy eyesight. The eye exercise program lasted from March, 1997 to November, 1997. On November, 1997, visual acuity was measured again from children in both schools. The data was analyzed by using SAS statistical package. The results indicate that the children in the experimental group had significantly (p〈0.001) better eyesight than the children in the control group. Also, some of the behavior highly related to the poor eyesight are poor maternal eyesight and watching TV from a short distance. In conclusion, one of the significance of this project is that the vision care program was developed after the need assessment. It will be encouraged in the future that more school health program should be developed after a need assessment. Also, inclusion of family members was important in health promoting projects within a school setting since healthy behavior needs to be reinforced at horne as well as at school.