• Geomechanics and Engineering
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• 제9권5호
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• pp.645-667
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• 2015

Single treatment and staged treatments in vertical wells are widely applied in sandstone and mudstone thin interbedded (SMTI) reservoir to stimulate the reservoir. The keys and difficulties of stimulating this category of formations are to avoid hydraulic fracture propagating through the interface between shale and sand as well as control the fracture height. In this paper, the cohesive zone method was utilized to build the 3-dimensional fracture dynamic propagation model in shale and sand interbedded formation based on the cohesive damage element. Staged treatments and single treatment were simulated by single fracture propagation model and double fractures propagation model respectively. Study on the changes of fracture vicinity stress field during propagation is to compare and analyze the parameters which influence the interfacial induced stresses between two different fracturing methods. As a result, we can prejudge how difficult it is that the fracture propagates along its height direction. The induced stress increases as the pumping rate increasing and it changes as a parabolic function of the fluid viscosity. The optimized pump rate is $4.8m^3/min$ and fluid viscosity is $0.1Pa{\cdot}s$ to avoid the over extending of hydraulic fracture in height direction. The simulation outcomes were applied in the field to optimize the treatment parameters and the staged treatments was suggested to get a better production than single treatment.

• 한국강구조학회 논문집
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• 제20권6호
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• pp.731-740
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• 2008

본 연구는 하부 절곡강판과 T형강을 D16mm 스터드 전단연결재를 이용하여 콘크리트와 일체화시킨 교량용 강합성 바닥판의 피로 거동 및 피로성능을 평가하기 위한 것이다. 제안된 강합성 바닥판의 피로성능 평가를 위하여 총 8본의 시험체가 제작되었으며, 각각의 시험체에 3 종류의 일정진폭을 가진 피로하중이 재하되었다. 피로실험결과, 피로균열은 강합성 바닥판 하부 절곡강판의 절곡점에서 발생하여 상부 T형강으로 진전되는 것으로 나타났으며, 피로하중에 따라 시험체의 변위 및 변형률이 증가하고 피로균열발생 후 변위와 변형률이 급격히 변화하였다. 제안된 강합성 바닥판의 피로강도는 도로교설계기준 및 도로교설계기준 피로상세 범주의 자료가 된 NCHRP 102와 NCHRP 147 보고서의 피로실험결 과와 비교하여 평가한 결과 대상 강합성 바닥판은 피로상세 범주 C에 해당하는 것으로 평가되었다.

• 한국학교보건학회지
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• 제11권1호
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• pp.63-74
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• 1998

The purposes of this study are to show in interpersonal relations what factors male students are stressed from, how they experience stress, how they cope With it in each situation, and what this results in It attempt to gam basic materials to promote male student health and positive coping methods, The subject of this study was 15 male students of C University located in Seoul and Kyeonggui-Do They were composed of 5 sophomores, 5 Juniors and 5 seniors The period for collecting materials was October 1997 to January 1998, and the interview time ranged from 50 minutes to two hours The interview frequency was one to three times as occasion demanded, The materials were analyzed by the methods and theory suggested by Strauss & Corbin (1990) The results were 130 categories grouped into 33 divisions by similarity Finally, they were united into 9 higher categories In interpersonal relations the core category of male student stress is "affliction", and it follows the course of generation-coping-resolution The types showed in the course of material analysis are as follows, (1) When the subject student is on good terms with the other and the stress is repeated- "affliction" is strong and continuous-and his ability sense is strong, he copes with "affliction" With his own will and solves It affirmatively, (2) When the subject student is on good terms with the other and the stress is repeated-so "affliction" is strong and continuous-and his ability sense is weak, he copes with "affliction" with an emotional bias and solves it negatively (3) When the subject student is on good terms with the other and the stress is temporary-"affliction" is strong and temporary-and his ability sense is strong, he copes with "affliction" with his own will and solves it affirmatively (4) When the subject student becomes estranged from the other and the stress is temporary-"affliction" is weak and temporary-and his ability sense is weak, he copes with "affliction" with an emotional bias and solves it negatively, (5) When the subject student becomes estranged from the other and the stress is repeated-"affliction" is strong-and continuous and his ability sense is strong, he copes with "affliction" with his own will and solves it affirmatively (6) When the subject student becomes estranged from the other and the stress is repeated-"affliction" is strong and continuous-and his ability sense is weak, he copes with "affliction" with an emotional bias and solves it negatively. According to the above results, the conditions of cause and effect for male students to generate "affliction" should be understood in order to help cope with stress caused by interpersonal relations A program for education and counseling should be developed for male students to strengthen their 'ability sense' in choosing coping strategies In addition, the individual estimation for ability sense should be performed when education and counseling them.

• 한국식품영양학회지
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• 제30권1호
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• pp.83-95
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• 2017

This study examined the socioeconomic factors that affect self-rated health (SRH) in healthy adults, and the relationship of SRH to health-related habits, serum biochemical indices, and nutritional intakes. Subjects consisted of 1,154 healthy adults without any known disease, aged 19 to 65 years (average age of 36.7), whose information was obtained from the 2013 Korean National Health and Nutritional Examination Survey data. Of these subjects, 73 rated themselves as 'very healthy,' 460 indicated that they were 'healthy,' 568 self-identified as 'ordinary', and 53 put themselves in the 'unhealthy' category. The proportion of subjects who chose 'unhealthy' was significantly increased with higher frequencies of disruptions in their daily lives (p<0.05), regret after drinking (p<0.05), smoking (p<0.001), and higher levels of stress (p<0.001). On the other hand, the proportion of subjects reported as 'very healthy' was significantly higher with regular intense (p<0.001) or moderate physical activities (p<0.05), regular walking (p<0.05), a perception of being 'normal' in their body image (p<0.01), a decrease of body weight more than 3 kg in the past year (p<0.05), and without risk factors for metabolic syndrome (p<0.05). Serum triglyceride level was lower, and 25-(OH) vitamin D content was significantly higher, in the 'very healthy' group as compared to the 'unhealthy' group (p<0.05). Dietary fiber and vitamin C intakes were significantly higher in the 'very healthy' group than 'unhealthy' group (p<0.05). The overall results suggest that a healthy lifestyle, including regular exercise, non-smoking, good stress management, and higher intakes of fiber and vitamin C, may be potential factors that affect one's positive perception of health.

• 한국사회복지학
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• 제69권2호
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• pp.219-246
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• 2017

본 연구는 트라우마 센터에 근무한 사회복지사들의 소진과 이차적 외상 스트레스 경험을 이해하기 위한 실체 이론 개발을 목적으로 한다. 근거이론을 통해 자료를 분석한 결과, 초기코딩을 통해서 159개의 의미단위, 47개의 하위범주, 그리고 12개의 범주를 구성하였다. 초점 코딩에서 중심현상을 '상처받은 존재성'으로 보고 '사회복지사로서의 자리 찾기'를 핵심범주로 정하였으며 이를 중심으로 연관된 범주들을 연결하였다. 이론적 코딩 결과 트라우마 센터에서 근무한 사회복지사의 소진과 이차적 외상 스트레스 경험 과정은 사명기, 갈등기, 침체기, 해체기로 나타났다. 이러한 연구 결과를 바탕으로 재난복지실천에 대한 준비, 트라우마 치유 관점에 대한 논의 및 합의, 그리고 소진과 이차적 외상 스트레스 예방과 대처를 위한 프로그램의 필요성을 제시하였다.

• 산업융합연구
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• 제21권3호
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• pp.117-127
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• 2023

본 연구는 코로나-19 범유행시 임산부의 생생한 경험을 현상학적 접근을 통해 탐구함으로 임산부의 스트레스 경험을 이해하기 위한 질적연구이다. 연구대상자는 COVID-19 범유행 기간 동안 임신한 임산부 12명을 대상자로 선정하여 심층면담하였다. 참여자의 인터뷰는 2022년 6월부터 10월까지 진행하였으며, Colaizzi (1978) 분석 방법을 사용하여 Taguette 프로그램을 통해 데이터를 분석하였다. 분석된 결과로는 경험의 범주가 4개의 주제와 12개의 하위 주제로 도출되었다. 주요 주제는 부정확한 정보로 인한 혼란, 무너진 산전관리, 통제된 삶으로 인한 스트레스, 적응해가는 몸과 마음으로 나타났다. 임산부의 건강을 위한 사회적 지원과 안정적인 의료시스템 구축이 전반적으로 이루어져야 할 필요가 있음이 확인되었다. 이를 뒷받침하기 위해서는 후속 연구들이 더 필요하다.

• 융합신호처리학회논문지
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• 제3권3호
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• pp.70-75
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• 2002

본 논문은 새로운 단일 전력단 역률보상 풀 브리지 컨버터를 제안하였다. 제안된 컨버터는 역률보상을 위하여 앞단에 2개의 인덕터, 2개의 다이오드, 2개의 자성결합 변압기를 가진 2VS 풀브리지 DC/DC 컨버터로 구성되어 있다. 이러한 구성방법에 의해 전력은 전원에서 분리되고, 안정된 직류출력전압을 얻을 수 있다. 이 토폴로지에서 주소자의 전압스트레스는 영전압스위칭에 의해서 감소되며, 또한 제안된 컨버터는 능동 역률보정 스위치와 제어 및 게이팅 보드와 같은 보조회로가 필요치 않게되어 규격과 단가를 낮출 수 있을 뿐 아니라 효율을 증가시킬 수 있다.

• 동의신경정신과학회지
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• 제17권2호
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• pp.199-207
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• 2006

Pain disorder is a category of somatoform disorder that be diagnosed when the pain is starting and getting worse associated with psychological factors. At the recent study, it revealed that stress might be more strong factor in occurring and sustaining the somatoform disorder. In this case, a 42 years old female patient had a chronic pain disorder 3 years ago, suddenly complained of an eyeball pain due to retina rupture induced by severe stress. In the view of oriental medicine, pain disorder belongs to GuQiJakTongJung. So, we diagnosed her state as GuQiJakTongJung and treated her such as herbal medicine, acupuncture and phlebotomy therapy. In result, the chronic pain of the patient was improved, and also general condition was getting better.

• Wind and Structures
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• 제19권5호
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• pp.523-540
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• 2014

This paper presents a comprehensive study of pressure developed on different faces of a 'Y' plan shape tall building using both numerical and experimental means. The experiment has been conducted in boundary layer wind tunnel located at Indian Institute of Technology Roorkee, India for flow condition corresponding to terrain category II of IS:875 (Part 3) - 1987, at a mean wind velocity of 10 m/s. Numerical study has been carried out under similar condition using computational fluid dynamics (CFD) package of ANSYS, namely ANSYS CFX. Two turbulence models, viz., $k-{\varepsilon}$ and Shear Stress Transport (SST) have been used. Good conformity among the numerical and experimental results have been observed with SST model yielding results of higher magnitude. Peculiar pressure distribution on certain faces has been observed due to interference effect. Furthermore, flow pattern around the model has also been studied to explain the phenomenon occurring around the model.

• Structural Engineering and Mechanics
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• 제81권3호
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• pp.379-394
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• 2022

Shallow footings usually belonged to the category of thick plate structures. For accurate analysis of thick plates, the contribution of out-of-plane components of the stress tensor should be considered in the formulation. Most of the available shallow footing models are based on the classical plate theories, which usually neglect the effects of the out-of-plane stresses. In this study, a mixed-field plate finite element model (FEM) is developed for the analysis of shallow footings rested on soil foundations. In addition to displacement field variables, the out-of-plane components of the stress tensor are also assumed as a priori unknown variables. For modeling the interaction effect of the soil under and outside of the shallow footings, the modified Vlasov theory is used. The tensionless nature of the supporting soil foundation is taken into account by adopting an incremental, iterative procedure. The equality requirement of displacements at the interface between the shallow footing and soil is fulfilled using the penalty approach. For validation of the present mixed FEM, the obtained results are compared with the results of 3D FEM and previous results published in the literature. The comparisons show the present mixed FEM is an efficient and accurate tool for solving the problems of shallow footings rested on subsoil.