• 화약ㆍ발파
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• 제41권4호
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• pp.17-28
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• 2023

최근 연구시설 및 자원개발 등의 목적으로 지하공간 활용이 증가하고 있으며, 저심도 암반을 넘어 고심도 암반에 대한 개발이 증가하고 있다. 고심도 지하공간 개발은 높은 응력과 높은 온도 조건에서의 암반의 안정성을 고려해야 한다. 고심도의 경우 암반 구조와 불연속면의 상태 등이 안정성에 영향을 미칠 뿐만 아니라 지진 및 굴착을 위한 암반발파에 의한 지반진동 전파가 지하공동의 응력변화를 발생시켜 암반의 안정성에 영향을 미치게 된다. 발파공학 측면에서 지반진동을 예측하는 방법은 실측 데이터를 바탕으로 통계학적 회귀분석을 통한 경험적 회귀모형과 수치해석적 방법이 사용되고 있다. 본 연구에서는 단일공 발파에 의한 폭발압력 전파특성과 지반진동 전파특성에 대한 경험적 회귀모형을 획득하기 위하여 실험적 방법을 통해 연구를 수행하였다.

• Journal of Forest and Environmental Science
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• 제39권4호
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• pp.246-253
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• 2023

Salix gracilistyla is widely distributed along riversides in Korea and very good for biomass production by SRC because of its excellent germination ability, but it is necessary to measure drying tolerance for cultivation. The drought tolerance of S. gracilistyla was tested using cuttings, and growth and physiological analysis were performed after irrigation was stopped. The growth inhibition of S. gracilistyla was observed from the day irrigation was stopped, and the soil moisture content decreased to less than 10% on the 25th day after irrigation was stopped. Over 50% of the seedlings turned brown 25 days after watering was stopped. The chlorophyll content of S. gracilistyla decreased dramatically after 25 days of stopping of irrigation. RWC values were unchanged until day 12 after irrigation was stopped but decreased rapidly until day 21, but there was a slightly decreasing trend after that. RWL levels increased slightly during irrigation stops. The proline content of plants subjected to drought stress was 0.91-2.63 mg/0.05 g, 2.75 times higher than that of the control treatment. The sugar content of the drought stress treatment group was 29.77 to 350.66 mg/0.05 g, which increased 12.24 times that of the control treatment. As a result of this study, S. gracilistyla was found to have a drought tolerance almost comparable to that of evergreen broad-leaved trees growing on the land. This study is expected to contribute to the resource utilization S. gracilistyla, a native willow tree of Korea, and the mass production of biomass by SRC.

• 문화기술의 융합
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• 제10권3호
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• pp.121-130
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• 2024

건강한 노년을 위하여 중년의 건강을 관리하는 것이 필요하다. 본 연구는 주관적 건강인지와 건강관련 삶의 질에 영향을 미치는 요인을 2020년 국민건강영양조사(KNHANES) 제8기 자료를 이용하여 40-59세 중년 여성 1068명의 데이터를 분석하였다. 연구방법은 STATA 15.0을 이용하여 복합표본 평균과 표준편차, 복합표본 가중치 백분율, 복합표본 t-test, 다중회귀분석을 수행 하였다. 주관적 건강과 건강관련 삶의 질에 영향을 미치는 복합공통요인은 교육수준, 가구원수, 우울증, 스트레스이었다. 연령, 폭음, 신체활동은 주관적 건강인지, 보험유형, 취업여부, 수면장애는 건강관련 삶의 질에 영향을 미치는 요인이었다. 중년기는 노년기로 넘어가는 전 단계로 중년의 주관적 건강 및 건강 관련 삶의 질을 향상시킬 수 있는 보건정책 프로그램을 개발하여야 할 것이다.

• International Journal of Automotive Technology
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• 제7권4호
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• pp.485-492
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• 2006

The AA5182/polypropylene/AA5182(AA/PP/AA) sandwich sheets have been developed for application to automotive body panels in future lightweight vehicles with significant weight reduction. It has been reported that the AA5182 aluminum sheet shows $L\"{u}ders$ band because of dissolved Mg atoms that cause fabrication process problem, especially surface roughness. The examination of serration behavior has been made after the tensile deformation of the AA/PP/AA sandwich sheets as well as that of the AA5182 aluminum skins at room and elevated temperatures. All sandwich sheets and the AA5182 aluminum skin showed serration behavior on their flow curves. However, the magnitude of serration was significantly diminished in the sandwich sheet with high volume fraction of the polypropylene core. According to the results of the analysis of the surface roughness following the tensile test, $L\"{u}ders$ band depth of the sandwich sheet evidently showed lower than that of the AA5182 aluminum skin. The strain rate sensitivity, m-value, of the AA5182 aluminum skin was -0.006. By attaching these skins to the polypropylene core, which has relatively large positive value of 0.050, m-value of the sandwich sheets changed to the positive value. The serration mechanism of the sandwich sheets was quantitatively investigated in the point of the effect on polypropylene thickness variation, that on the strain rate sensitivity and that on the localized stress state.

• ETRI Journal
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• 제38권4호
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• pp.787-797
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• 2016

Mining, construction, and other special vehicles for heavy use are designed to work under high-performance and off-road working conditions. The driving and executive mechanisms of the support structures and superstructures of these vehicles frequently operate under high loads. Such high loads place the equipment under constant risk of an accident and can jeopardize the dynamic stability of the machinery. An experimental investigation was conducted on a refuse collection vehicle. The aim of this research was to determine the working conditions of a real vehicle: the kinematics of the waste container, that is, a hydraulic rotate drum for waste collection; the dynamics of the load manipulator (superstructure); the vibrations of the vehicle mass; and the strain (stress) of the elements responsible for the supporting structure. For an examination of the force (weight) on the rear axle of a heavy vehicle, caused by its own weight and additional load, a universal measurement system is proposed. As a result of this investigation, we propose an alternative system for continuous vehicle weighing during waste collection while in motion, that is, an on-board weighing system, and provide suggestions for measuring equipment designs.

• 한국건강관리협회지
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• 제2권3호
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• pp.73-96
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• 2004

Along with a development of medical technology, a variety of tests, such as laboratory tests, x-ray and endoscopies are being used in health screening tests. As the tests determine the quality of health screening, test items and methods should be carefully selected. This study was to get hold of the test items of major health screening programs in Korea Most of the health screening programmes focused upon detection of risk factors and diagnosis of life - style related diseases (diabetes, hypertension, cardiovascular diseases, hypercholesterolemia, overweight, drinking, smoking, cerebrovascular diseases, osteoporosis) ,cancers (stomach, cervix, lung, breast, liver, colon, prostate, ovary, pancreas, thyroid, esophagus) , infectious diseases (hepatitis, tuberculosis, sexually-transmitted diseases, parasites) , chronic obstructive respiratory diseases, chronic renal diseases (bacteriuria hematuria, proteinuria) , anemia, glaucoma, hearing loss, Alzheimer disease, stress, early psychiatric diseases. The health screening tests were basic physical examination, basic laboratory tests (CBC, urinalysis, liver function tests, lipid tests, glucose, HbAlc, uric acid, electrolytes, serological tests (HBsAg, HBs-Ab, HCV-Ab, HIV-Ab, VDRL) EKG, x-ray (chest PA, CT) , endoscopy (gastroscopy, colonoscopy) , sonography(abdomen, thyroid, pelvis, breast) ,cytology (cervix) , bone density, tumor markets (NMP22, alpha-FP, CEA, CA-19-9, CA12S, PSA) and eye tests. Advanced technologies, like CT, PET, MRI, MRT/Angio, molecular testings) were widely used in hospital health screening programmes .In summary, a variety of tests were utilized in health screening in Korea. Those tests were utilized by stages or according to sex and age in most of health screening programmes, however a few program used tests to excess disregarding health screening subjects.

• 대한족부족관절학회지
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• 제22권2호
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• pp.55-61
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• 2018

Chronic lateral ankle instability is a major complication of acute ankle sprains, which can cause discomfort in both daily and sports activity. In addition, it may result in degenerative changes to the ankle joint in the long term. An accurate diagnostic approach and successful treatment plan can be established based on a comprehensive understanding of the concept of functional and mechanical instability. The patients' history and correct physical examination would be the first and most important step. The hindfoot alignment, competence of the lateral ligaments, and proprioceptive function should be evaluated. Additional information can be gathered using standard and stress radiographs. In addition, concomitant pathologic conditions can be investigated by magnetic resonance imaging. Conservative rehabilitation composed of the range of motion, muscle strengthening, and proprioceptive exercise is the main treatment for functional instability and mechanical instability. Regarding the mechanical instability, surgical treatment can be considered for irresponsible patients after a sufficient period of rehabilitation. Anatomic repair (modified $Brostr{\ddot{o}}m$ operation) is regarded as the gold standard procedure. In cases with poor prognostic factors, an anatomical reconstruction or additional procedures can be chosen. For combined intra-articular pathologies, arthroscopic procedures should be conducted, and arthroscopic lateral ligament repair has recently been introduced. Regarding the postoperative management, early functional rehabilitation with short term immobilization is recommended.

• 한국건강관리협회지
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• 제2권1호
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• pp.9-25
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• 2004

Along with a development of medical technology, a variety of tests, such as laboratory tests, x-ray and endoscopies are being used in health screening tests. As the tests determine the quality of health screening, test items of major health screening program in Korea. Most, of the health screening programmes focused upon detection of risk factors and diagnosis of life-style related diseases(diabetes, hypertension, cardiovascular diseases, hypercholesterolemia, overweight, drinking, smoking, cerebrovascular diseases, osteoporosis), cancers(stomach, cervix, lung, breast, liver, colon, prostate, ovary, pancreas, thyroid, esophagus), infections diseases(hepatitis, tuberculosis, sexually-transmitted diseases, parasites), chronic obstructive respiratory diseases, chronic renal diseases(bacteriuria, hematuria, proteinuria), anemia, glaucoma, hearing loss, Alzheimer disease, stress and earlypsychiatric diseases. The health screening tests were basic physical examination, basic laboratory tests( CBC, urinalysis, liver function tests, lipid tests, glucose, HbA1c, uric acid, electrolytes, serological tests(HBsAg, HBs-Ab, HCV-Ab, HIV-Ab, VDRL) EKG, x-ray(chest PA, CT) endoscopy(gastroscopy, colonoscopy), sonography (abdomen, thyroid, pelvis, breast), cytology(cervix), bone density, tumor markers(NMP22, alpha-FP, CEA, CA-19-9, CA125, PSA and eye tests. Advanced technologies, like CT, PET, MRI, MRI/Angio, molecular testing were widly used in hospital based health screening programmes. In summary, a variety of tests were untilized in health screening in Korea. Those tests were utilized by stages or according to sex and age in most of health screening programmes, however a few programs used tests excessvely disregarding health screening subjects.

• 지역사회간호학회지
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• 제25권1호
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• pp.24-32
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• 2014

Purpose: The purpose of this study is to describe the prevalence of suicidal ideation and to investigate related factors contributing to suicidal ideation in elderly people with focus on comparison of gender differences. Methods: From the database of the Fourth Korean National Health and Nutrition Examination Survey (KNHANES-IV), the researchers selected 3,164 old adults aged over 65. The original study was a population-based epidemiological survey of health and nutrition in a stratified multistage clustered probability design. Data were analyzed by using ${\chi}^2$-test and t-test and multiple logistic regression with the SPSS/WIN18.0 program. Results: Suicidal ideation in women (37.5%) occurred more frequently than men (17.5%). Depression, stress, restriction on activities and quality of life were significant variables of suicidal ideation in both the men and women aged 65 over. Low educational levels and economic states were significantly associated with suicidal ideation in men but not in women. Conclusion: The development of a suicide prevention program for elders requires different approaches to the genders respectively. It is also recommended that programs be developed that can help control the variables identified in this study along with a follow-up study for verifying the model.

• Composites Research
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• 제27권4호
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• pp.152-157
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• 2014

Non-destructive testing methods of composite materials are very important for improving material reliability and safety. AE measurement is based on the detection of microscopic surface movements from stress waves in a material during the fracture process. The examination of AE is a useful tool for the sensitive detection and location of active damage in polymer and composite materials. FBG (Fiber Bragg Grating) sensors have attracted much interest owing to the important advantages of optical fiber sensing. Compared to conventional electronic sensors, fiber-optical sensors are known for their high resolution and high accuracy. Furthermore, they offer important advantages such as immunity to electromagnetic interference, and electrically passive operation. In this paper, the crack detection capability of AE (Acoustic Emission) measurement was compared with that of an FBG sensor under tensile testing and buckling test of composite materials. The AE signals of the PVDF sensor were measured and an AE signal analyzer, which had a low pass filter and a resonance filter, was designed and fabricated. Also, the wavelength variation of the FBG sensor was measured and its strain was calculated. Calculated strains were compared with those determined by finite element analysis.