• Coupled systems mechanics
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• 제6권2호
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• pp.189-206
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• 2017

Tanks are used to store a wide variety of liquids such as oil, gasoline and water. It is reported that, a large number of tanks have been damaged during severe earthquakes. Therefore, understanding their behavior under earthquake is an important subject for structural engineers. In this paper, a comprehensive study is presented on dynamic response of tanks. A parametric study has been completed on the rectangular storage tanks with aid of finite element method (FEM). Various parameters are investigated, such as; liquid height, density and earthquake with different peak ground acceleration (PGA). When investigating these parameters, modal and time history method is used. Six different earthquake records are used for time history analysis. The analysis results show that when the PGA increases by 10.7 times, the maximum displacements, stress, sloshing and base shear increase by 11.4, 22.6, 5.46 and 17.8 times, respectively and when the liquid height increases by two times, the absolute maximum values of stress, displacements, base shear and sloshing increase 1.65, 2.04, 2.05 and 1.34. Furthermore, values of sloshing increase with decrease in density.

• The Korean Journal of Pain
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• 제33권2호
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• pp.153-165
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• 2020

Background: Well-validated risk prediction models help to identify individuals at high risk of diseases and suggest preventive measures. A recent systematic review reported lack of validated prediction models for low back pain (LBP). We aimed to develop prediction models to estimate the 8-year risk of developing LBP and its recurrence. Methods: A population based prospective cohort study using data from 435,968 participants in the National Health Insurance Service-National Sample Cohort enrolled from 2002 to 2010. We used Cox proportional hazards models. Results: During median follow-up period of 8.4 years, there were 143,396 (32.9%) first onset LBP cases. The prediction model of first onset consisted of age, sex, income grade, alcohol consumption, physical exercise, body mass index (BMI), total cholesterol, blood pressure, and medical history of diseases. The model of 5-year recurrence risk was comprised of age, sex, income grade, BMI, length of prescription, and medical history of diseases. The Harrell's C-statistic was 0.812 (95% confidence interval [CI], 0.804-0.820) and 0.916 (95% CI, 0.907-0.924) in validation cohorts of LBP onset and recurrence models, respectively. Age, disc degeneration, and sex conferred the highest risk points for onset, whereas age, spondylolisthesis, and disc degeneration conferred the highest risk for recurrence. Conclusions: LBP risk prediction models and simplified risk scores have been developed and validated using data from general medical practice. This study also offers an opportunity for external validation and updating of the models by incorporating other risk predictors in other settings, especially in this era of precision medicine.

• Korean Journal of Acupuncture
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• 제25권4호
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• pp.1-15
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• 2008

Objectives : This study is designed to investigate the association between Samcho-gyeong(TE) and the lower branch of Meridian system. Methods : The base of the study was established by searching for the historic conception of Samcho. Thereafter the meaning of lower correlation was considered and the property of lower part of Samcho Meridian system studied. Results : Samcho is a kind of Yug-Bu(Six hollow viscera, 六腑). It is a functional internal organ, which has been continuously controversial in history. It covers wide range of the internal organs and plays various kinds of roles. Samcho and Simpo lack in interrelation of obverse and reverse. The conception of Sanghap(Upper correlation, 上合) in Naegyeong supplements the deficiency. To establish the conception of Sanghap between Yug-Bu and Hand meridians, there should be established the conception of Hahap(Lower correlation, 下合) between Yug-Bu and foot meridians for treating lower parts. The existence of Hahaphyeol(Lower confluent points, 下合穴) reveals that there were a lot of limits in treating JungHa-cho(Middle and Lower energizers, 中下焦) diseases only with the acupoints of the Hand meridians. Jogsamcho(Triple energizer of foot, 足三焦) meridian written in Taeso(太素), corresponds to the lower leg, and it is believed that it engages in treating diseases in the trunk of the body and Hacho(Lower energizer, 下焦). Conclusions : Therefore, it is believed that the lower part of meridian of Samcho can deal with the symptoms of lower back pain, leg pain, bladder disease, and so on. This study is meaningful in that it expands the range of treatment in acupoints of the regular meridians.

• Journal of Chest Surgery
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• 제42권3호
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• pp.380-383
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• 2009

쇄골하 동맥의 동맥류는 매우 드문 질환으로 외상, 감염 및 동맥 경화증 등에 의하여 발생하는 것으로 알려져 있다. 증례는 외상 및 감염 등의 과거력이 없는 69세 여자 환자로, 목 부위의 종괴로 발현된 쇄골하 동맥의 분지에 국한된 동맥류로 진단되어 수술적 치료를 하였다. 저자들은 이에 문헌 고찰과 함께 보고하는 바이다.

• 한국대기환경학회지
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• 제26권2호
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• pp.202-218
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• 2010

It is well known that the atmospheric inorganic aerosol has the hysteresis phenomena depending on the history of relative humidity. However, the current computational researches have assumed that the physical/chemical state of atmospheric aerosol is only determined by a branch of hysteresis, efflorescence or deliquescence. In this work, we applied the MATLAB-based UHAEROm thermodynamics module to simulate the dynamic interaction between gaseous species $NH_3$ and $HNO_3$, and the two mono-disperse particulate populations in the course of efflorescence and deliquescence, respectively. We conducted the 10 case studies considering the particulate phase with the atmospherically prevailing chemical composition and found that the final states of the particles are determined through the qualitatively five different trajectories by the dynamic interaction between gaseous and two different kinds of particulates. As a result, we show that the coexistence of meta-stable and stable particles drives the different physical/chemical destination comparing with the ones generated from the solitary efflorescence or deliquescence branch.

• 공학교육연구
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• 제15권5호
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• pp.14-18
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• 2012

Shu-gyo-ryoku, a program to enhance students' academic and career skills, was begun in the academic year 2011. Under the new program, "Career Planning" and "Career Design" were introduced as part of the liberal arts education for incoming freshmen. Approximately 500 students majoring in engineering enrolled in "Career Planning" in which they study a "curriculum map" and how it relates to their future fields of employment. The curriculum map illustrates the connections between classes and increases students'understanding of the curriculum structure. In small groups, students discussed the curriculum in order to develop sketches of their career paths. In addition, students answered a career anchor test and though several communicative activities, improved their communication skills. A portfolio system was built into the university network to record the learning history of each student. Students are able to check their learning histories and reflect on the change in themselves during their academic careers.

• Asian Pacific Journal of Cancer Prevention
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• 제16권2호
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• pp.451-455
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• 2015

More than one million new patients suffer from breast cancer annually in the world. In developed countries, breast cancer is the most common malignancy diagnosed among women, and in developing regions, it often ranks second to cervical cancer. This study aimed to investigate the relationship between incidence of breast cancer and reproductive factors in North-West of Iran. This retrospective analytical control-case study was conducted with 235 breast cancer patients and 235 women in the control group. Data collection tools included a set of questions with interviews and patient medical records. Data were analyzed using statistical tests: t-test, Chi-square, Fisher, and Pearson correlation coefficient. Significantly increased risks were associated between breast cancer and older age at first pregnancy, age at menopause and history of contraceptive use. A trend for decreasing risk were observed with increasing parity. Findings of this study showed no association between breast cancer and age at menarche. The study results suggested that physiological and reproductive factors may play important roles in the development breast cancer among Iranian women.

• 한국응용곤충학회지
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• 제39권2호
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• pp.83-87
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• 2000

최근 강원도 원주 등지에서 은행나무에 큰 피해를 주었던 대만나방의 생활사를 1998년부터 1999년까지 조사하였다. 현재까지 우리 나라에서는 자세히 보고된 바 없는 알, 유충, 번데기 및 성충의 형태적 특징과 각 충태별 기간 및 생태적 특성을 조사하였다. 대만나방은 연 1회 발생하였으며, 6령충으로 기주식물의 가지에서 월동하였다. 유충은 총 9령을 거치며, 종령유충은 6월하순경에 가지에서 은행잎 2-3장을 엮은뒤 갈색실을 토하여 고치를 틀고 그 속에서 번데기가 되었다. 성충은 7월초순부터 8월초순에 걸쳐 우화하였으며 우화최성기는 7월하순이었다. 교미한 암컷은 평균 205개의 알을 난괴형태로 산란하였으며, 산란장소는 가지, 줄기, 또는 잎의 가장자리였다.

• 천문학회보
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• 제43권1호
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• pp.46.1-46.1
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• 2018

In order to investigate the origin of multiple stellar populations in the halo and bulge of the Milky Way, we have constructed chemical evolution models for the low-mass proto-Galactic subsystems such as globular clusters. Unlike previous studies, we assume that supernova blast waves undergo blowout without expelling the pre-enriched gas, while relatively slow winds of massive stars, together with the winds and ejecta from low and intermediate mass asymptotic-giant-branch stars, are all locally retained in these less massive systems. We find that the observed Na-O anti-correlations in metal-poor GCs can be reproduced when multiple episodes of starbursts are allowed to continue in these subsystems. A specific form of star formation history with decreasing time intervals between the stellar generations, however, is required to obtain this result, which is in good agreement with the parameters obtained from our stellar evolution models for the horizontal-branch. The "mass budget problem" is also much alleviated by our models without ad-hoc assumptions on star formation efficiency and initial mass function. We also applied these models to investigate the origin of super helium-rich red clump stars in the metal-rich bulge as recently suggested by Lee et al. (2015). We find that chemical enrichments by the winds of massive stars can naturally reproduce the required helium enhancement (dY/dZ = 6) for the second-generation stars. Disruption of proto-globular clusters in a hierarchical merging paradigm would have provided helium enhanced stars to the bulge field.

• Structural Engineering and Mechanics
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• 제69권6호
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• pp.651-665
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• 2019

Past earthquakes have shown that appropriately designed and detailed buildings with shear walls have great performance such a way that a considerable portion of inelastic energy dissipation occurs in these structural elements. A plastic hinge is fundamentally an energy diminishing means which decrease seismic input energy through the inelastic deformation. Plastic hinge development in a RC shear wall in the areas which have plastic behavior depends on the ground motions characteristics as well as shear wall details. One of the most generally used forms of structural walls is flanged RC wall. Because of the flanges, these types of shear walls have large in-plane and out-of-plane stiffness and develop high shear stresses. Hence, the purpose of this paper is to evaluate the main characteristics of these structural components and provide a more comprehensive expression of plastic hinge length in the application of performance-based seismic design method and promote the development of seismic design codes for shear walls. In this regard, the effects of axial load level, wall height, wall web and flange length, as well as various features of earthquakes, are examined numerically by finite element methods and the outcomes are compared with consistent experimental data. Based on the results, a new expression is developed which can be utilized to determine the length of plastic hinge area in the flanged RC shear walls.