• 한국융합학회논문지
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• 제11권3호
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• pp.145-152
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• 2020

본 연구의 목적은 우리나라 청소년의 성경험 유무에 따른 건강행태의 차이를 파악하기 위한 융복합 연구이다. 본 연구는 2017년 청소년건강행태온라인 조사의 원시자료를 이용한 이차 분석 연구로, 총 61,861명의 자료를 분석하였다. 연구결과 성경험이 있는 청소년에서 남학생, 고등학생, 남학교, 낮은 학업성적, 부모와 따로 거주, 높거나 낮은 경제 상태를 가지는 것으로 나타났다. 건강행태에 있어서는 성경험이 있는 청소년이 신체활동을 더 많이 하고 스트레스, 슬픔·절망감 경험, 자살생각, 자살계획, 자살시도, 음주, 흡연을 더 많이 하는 것으로 나타났다. 성경험이 있는 청소년 중에서 피임을 하지 않는 청소년은 48.9%로 나타났고, 주로 콘돔을 이용하였다. 청소년의 성 건강을 위하여 본 연구에서 도출된 요인을 고려하여 중재하는 것이 필요하다. 따라서 본 연구는 청소년의 특성을 반영한 성교육 프로그램을 개발하는 데에 기여할 수 있을 것이다.

• 전력전자학회논문지
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• 제19권1호
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• pp.91-97
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• 2014

Recently, the LED(Light Emitting Diode) is expected to replace conventional lamps including incandescent, halogen and fluorescent lamps for some general illumination application, due to some obvious features such as high luminous efficiency, safety, long life, environment-friendly characteristics and so on. To drive the LED, a single stage PFC(Power Factor Correction) flyback converter has been adopted to satisfy the isolation, PFC and low cost. The conventional flyback LED driver has the serious disadvantage of high 120Hz output current ripple caused by the PFC operation. To overcome this drawback, a new PFC flyback with low 120Hz output current ripple is proposed in this paper. It is composed of 2 power stages, the DCM(Discontinuous Conduction Mode) flyback converter for PFC and BCM(Boundary Conduction Mode) boost converter for tightly regulated LED current. Since the link capacitor is located in the secondary side, its voltage stress is small. Moreover, since the driver is composed of 2 power stages, small output filter and link capacitor can be used. Especially, since the flyback is operated at DCM, the PFC can be automatically obtained and thus, an additional PFC IC is not necessary. Therefore, only one control IC for BCM boost converter is required. To confirm the validity of the proposed converter, theoretical analysis and experimental results from a prototype of 24W LED driver are presented.

• 한국재료학회지
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• 제21권11호
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• pp.596-603
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• 2011

The very high temperature gas reactor (VHTR) is one of the next generation nuclear reactors for its safety, long-term stability, and proliferation-resistance. The high operating temperature of over 800$^{\circ}C$ enables various applications with high energy efficiency. Heat is transferred from the primary helium loop to the secondary helium loop through the intermediate heat exchanger (IHX). The IHX material requires creep resistance, oxidation resistance, and corrosion resistance in a helium environment at high operating temperatures. A Ni-based superalloy such as Alloy 617 is considered as a primary candidate material for the intermediate heat exchanger. In this study, the microstructures of Alloy 617 crept in pure helium and air environments at 950$^{\circ}C$ were observed. The rupture time in helium was shorter than that in air under small applied stresses. As the exposure time increased, the thickness of outer oxide layer of the specimens clearly increased but delaminated after a long creep time. The depth of the carbide-depleted zone was rather high in the specimens under high applied stress. The reason was elucidated by the comparison between the ruptured region and grip region of the samples. It is considered that decarburization caused by minor gas impurities in a helium environment caused the reduction in creep rupture time.

• 보건의료산업학회지
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• 제5권2호
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• pp.77-89
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• 2011

This study conducted a secondary analysis by using original data of performed by Korea Institute for Health and Social Affairs to know factors affecting determinants of health using Lalonde model for the adults aged over 19 years living in Korea. The survey was conducted in 2009 and it evaluated finally 5,867 cases by excluding cases with no answer or a wrong answer. This study model adopted two categories of instrument measure health were objective (Average remaining lifetime) and subjective(EQ-5D) health status. The health determinants included in this study could be divided in to four categories, which were human biology, environment, lifestyle, and health care organization. The results were as follows. In the factors affecting average remaining lifetime, human biology were sex, ages, BMI, showed statistically significant difference, environment category were merry status, education showed statistically significant difference, lifestyle category were exercise, drunks showed statistically significant difference and health care organization category were vaccination, health screening showed statistically significant difference. In the factors affecting EQ-5D, human biology category and health care organization category showed with same average remaining lifetime, environment category were merry status, education, income showed statistically significant difference and lifestyle category were exercise, drunks, stress showed statistically significant difference. The results demonstrated that the best powerful factor was life style category and environment category, the least factor was health care organization category. So lifestyle style and environment category should be considered for the future health plan, budget allocation and the priority in the health care.

• 한국해양공학회지
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• 제21권6호
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• pp.7-15
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• 2007

A mechanical model was developed to predict the behavior of point-loaded RC slender beams (a/d > 2.5) without stirrups. It is commonly accepted by most researchers that a diagonal tension crack plays a predominant role in the failure mode of these beams, but the failure mechanism of these members is still debatable. In this paper, it was assumed that diagonal tension failure was triggered by the concrete cover splitting due to the dowel action at the initial location of diagonal tension cracks, which propagate from flexural cracks. When concrete cover splitting occurred, the shape of a diagonal tension crack was simultaneously developed, which can be determined from the principal tensile stress trajectory. This fictitious crack rotates onto the crack tip with load increase. During the rotation, all forces acting on the crack (i.e, dowel force of longitudinal bars, vertical component of concrete tensile force, shear force by aggregate interlock, shear force in compression zone) were calculated by considering the kinematical conditions such as crack width or sliding. These forces except for the shear force in the compression zone were uncoupled with respect to crack width and sliding by the proposed constitutive relations for friction along the crack. Uncoupling the shear forces along the crack was aimed at distinguishing each force from the total shear force and clarifying the failure mechanism of RC slender beams without stirrups. In addition, a proposed method deriving the dowel force of longitudinal bars made it possible to predict the secondary shear failure. The proposed model can be used to predict not only the entire behavior of point-loaded RC slender shear beams, but also the ultimate shear strength. The experiments used to validate the proposed model are reported in a companion paper.

• 여성건강간호학회지
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• 제26권2호
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• pp.141-150
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• 2020

Purpose: High-quality nursing care must be provided for women with infertility, and their nursing needs must be identified. Although scales have been developed to assess infertility-related stress, quality of life, and psychosocial status, there is a lack of scales that assess the nursing needs of women with infertility. The purpose of this study was to develop a needs assessment scale for nursing care in women with infertility and to verify its reliability and validity. Methods: The 250 subjects in this study were women with infertility recruited from four hospitals. The scale was developed following the framework of DeVellis, through a literature review, in-depth interviews, development of preliminary items, verification of content validity, development of secondary items, verification of construct validity, and extraction of the final items. Date were analyzed using item analysis, factor analysis, confirmatory factor analysis, Pearson correlation coefficients, and Cronbach's alpha. Reliability was tested using Cronbach's alpha, and validity was evaluated using item analysis, exploratory factor analysis, and criterion validity. Results: The final version of the nursing needs assessment scale for woman with infertility consisted of 18 items. Four factors (physical and psychological nursing needs, needs for information regarding treatment, needs for infertility-related understanding and concern, and supportive needs) explained 66.0% of the total variance. Cronbach's alpha was .92 for the overall instrument and ranged from .88 to .91 for the subscales. Conclusion: These results suggest that this needs assessment scale for nursing care in women with infertility demonstrated acceptable validity and reliability and contained items suitable for assessing the level of nursing care needed by women with infertility.

• 여성건강간호학회지
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• 제26권2호
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• pp.131-140
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• 2020

Purpose: The purpose of this study was to compare the health-related quality of life of premature menopausal women with that of normal postmenopausal women and to identify factors related to quality of life in these two groups. Methods: A secondary analysis was conducted of a sample of 5,910 postmenopausal women drawn from women aged 19-79 years, using raw data from the Korea National Health and Nutrition Survey between 2014 and 2017. Quality of life was compared between premature menopausal women and normal postmenopausal women using the t-test and chi-square test, and factors related to quality of life were analyzed by multivariate logistic regression using SAS version 9.4. Results: There was no significant difference in quality of life between premature menopausal women and normal postmenopausal women. Subjective health status and symptoms of depression were identified as factors related to quality of life in women with premature menopause, while engaging in aerobic physical activity, subjective health status, stress, and symptoms of depression were found to be related to quality of life among normal postmenopausal women. Conclusion: It is necessary to support self-care measures for both premature and normal menopausal women to adapt to changes caused by menopause, and multidimensional strategies should be developed considering postmenopausal women's subjective health status and symptoms of depression to improve their quality of life.

• Journal of Yeungnam Medical Science
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• 제35권1호
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• pp.54-62
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• 2018

Background: The type and regimen of anesthesia may affect perioperative hyperglycemia following major surgical stress. This study compared the effects of sevoflurane and propofol on the incidence of hyperglycemia and clinical outcomes in diabetic patients undergoing lung surgery. Methods: This retrospective study included 176 patients with type 2 diabetes mellitus who had undergone lung surgery. Blood glucose levels and clinical outcomes from the preoperative period to the first 2 postoperative days (PODs) were retrospectively examined in patients who received sevoflurane (group S, n= 87) and propofol (group P, n=89) for maintenance of general anesthesia. The primary endpoint was the incidence of persistent hyperglycemia (2 consecutive blood glucose levels >180 mg/dL [10.0 mmol/L]) during the perioperative period. The secondary composite endpoint was the incidence of major postoperative complications and 30-day mortality rate after surgery. Results: Blood glucose levels similarly increased from the preoperative period to the second POD in both groups (p=0.857). Although blood glucose levels at 2 hours after surgery were significantly lower in group P than in group S (p=0.022; 95% confidence interval for mean difference, -27.154 to -2.090), there was no difference in the incidence of persistent hyperglycemia during the perioperative period (group S, 70%; group P, 69%; p=0.816). The composite of major postoperative complications and all-cause in-hospital and 30-day mortality rates were also comparable between the two groups. Conclusion: Sevoflurane and propofol were associated with a comparable incidence of perioperative hyperglycemia and clinical outcomes in diabetic patients undergoing lung surgery.

• 비교교육연구
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• 제22권4호
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• pp.125-147
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• 2012

본 연구의 목적은 영국 대학 입학전형 제도를 명문대학의 면접고사를 중심으로 고찰하기 위한 것이다. 이러한 목적을 위해, 영국 중등학교 제도와 전형요소, 그리고 영국 대학입학 전형의 특징을 고찰하고, 영국 명문대학의 입학전형 방법과 면접고사에 대해 상세히 살펴보았다. 영국 대학의 입학사정은 다양한 전형 요소들을 확인하며, 이러한 작업은 모두 대학에서 요구하는 학업능력과 잠재능력을 확인하는데 초점을 둔다. 영국의 명문대학은 영국과 세계 각국의 최우수 학생들을 대상으로 잠재능력과 각 대학이 요구하는 특정 능력을 변별하기 위해 면접고사를 실시한다. 영국 대학의 면접고사는 우리나라 대학입학 전형이 어떤 인재를 선발할 것인지에 대한 기본 철학 측면과 면접고사의 본질과 신뢰도를 제고하는 실제 측면에 중요한 함의를 제공해 주고 있다.

• Geomechanics and Engineering
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• 제19권2호
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• pp.105-114
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• 2019

In this paper, simulation tests were conducted with similar materials to study the distribution of residual voids in longwall goaf. Short-time step loading was used to simulate the obvious deformation period in the later stage of arch breeding. Long-time constant loading was used to simulate the rheological stage of the arch forming. The results show that the irregular caving zone is the key area of old goaf for the subsidence control. The evolution process of the stress arch and fracture arch in stope can be divided into two stages: arch breeding stage and arch forming stage. In the arch breeding stage, broken rocks are initially caved and accumulated in the goaf, followed by the step deformation. Arch forming stage is the rheological deformation period of broken rocks. In addition, under the certain loads, the broken rock mass undergoes single sliding deformation and composite crushing deformation. The void of broken rock mass decreases gradually in short-time step loading stage. Under the water lubrication, a secondary sliding deformation occurs, leading to the acceleration of the broken rock mass deformation. Based on above research, the concept of equivalent height of residual voids was proposed, and whose calculation equations were developed. Finally, the conceptual model was verified by the field measurement data.