• 한국전기전자재료학회논문지
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• 제30권12호
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• pp.762-767
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• 2017

Mullite ($3Al_2O_3{\cdot}2SiO_2$) has emerged as a promising candidate for high-temperature structural materials due to its erosion resistance, chemical and thermal stabilities, relatively low thermal expansion coefficient, excellent thermal shock and creep resistances, and low dielectric constant. However, since the pure mullite sintering temperature is as high as $1,600{\sim}1,700^{\circ}C$, there is an increasing need for a sintering additive capable of improving the strength characteristics while lowering the sintering temperature. Herein we have tried to obtain the optimal sintering additive composition by adding MgO, $Cr_2O_3$, and $Y_2O_3$ to mullite, followed by sintering at $1,325{\sim}1,550^{\circ}C$ for 2 h. With additives of 2 wt% of MgO, 2 wt% of $Cr_2O_3$, 4 wt% of $Y_2O_3$, A density of $3.23g/cm^3$ was obtained for the sintered body at $1,350^{\circ}C$ upon using 2 wt% MgO, 2 wt% $Cr_2O_3$, and 4 wt% $Y_2O_3$ as additives. The three-point flexural strength of that was 275 MPa and the coefficient of thermal expansion (CTE) was $4.15ppm/^{\circ}C$.

• Journal of Acupuncture Research
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• 제35권1호
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• pp.37-40
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• 2018

Background: The purpose of this study was to compare the first branch of the bladder meridian (FBBM) as determined by the proportional bone measurement method (PBMM), to the line formed by the erector spinae muscle group, and to establish an academic basis for selection of acupuncture points and needling. Methods: Sixty participants were divided into 3 groups based on body mass index (BMI) and into 2 groups based on waist/height ratios. The distance from the midline of the spine to the first branch of the bladder meridian with PBMM (DFBBM), and the distance from the midline of the spine to the most elevated fleshy region of the erector spinae (DMEFR), at the same level as the inferior border of the spinous processes of L1-L5, were measured. The DFBBM and the 5 DMEFRs were then analyzed according to BMI and the waist/height ratio. Results: DFBBM was statistically different from DMEFR in all back-shu points in the lumbar region. DFBBM was not significantly different from DMEFR in the groups with a high BMI or waist/height ratio. However, there was a statistical difference in the groups with a low or moderate BMI or low waist/height ratio. Conclusion: Since the location of the most elevated fleshy region of the erector spinae does not coincide with the location of the FBBM, the selection of back-shu points in the lumbar region must be performed precisely by PBMM.

• 대한약침학회지
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• 제23권4호
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• pp.201-211
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• 2020

Objectives: The purpose of this study is to comprehensively review Korean domestic studies and investigate the research trends of pharmacopuncture therapy on cervical pain caused by traffic accidents. Methods: Domestic studies between February 1999 and May 2020 from four Korean databases were searched with combinations of keywords 'cervical pain', 'traffic accident', 'whiplash injury', and 'pharmacopuncture'. Results: 17 studies were selected for review, including 7 randomized controlled trials, 5 retrospective observational studies, 3 case reports, and 2 non-randomized controlled trials. Each study was reviewed by published year, study type, types of pharmacopuncture solutions, selected acupuncture points, dosage of pharmacopuncture solutions, frequency of treatment, concurrent treatments, outcome measurements, and the effectiveness of pharmacopuncture therapy. The results are as follows: (1) It showed that the total number of published studies had increased slightly in the last 10 years compared to the previous decade. (2) The pharmacopuncture solutions used in the studies were in the following order: Bee-Venom (蜂毒), Jungsongouhyul (中性瘀血), Hwangryunhaedoktang (黃連解毒湯) and Soyeom (消炎). Frequently used acupuncture points were GB20, GV21, A-shi point, GV16, EX-B2, and SI15 in order. (3) The most commonly used total injection dosage was 1.0 cc at a time, and the frequency of treatment was twice a week. (4) Concurrent treatments such as acupuncture, herbal medication, physical therapy and Chuna manual therapy were performed in all 17 studies. (5) Pharmacopuncture therapy showed positive effects on cervical pain caused by traffic accidents in all 17 studies reviewed. Conclusion: Pharmacopuncture therapy was effective in cervical pain caused by traffic accidents in all 17 studies selected. Further studies will be needed using more larger scales and more objective data to confirm the effectiveness of pharmacopuncture therapy and to generalize its application.

• 한국조경학회지
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• 제37권6호
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• pp.19-27
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• 2010

본 연구의 목적은 시민들에 의해 공공서비스의 관점에서 설정된 주요 항목으로 도시공원녹지를 평가하는데 있다. 본 연구를 수행하기 위해 대전광역시를 대상으로 5개구 80개동으로부터 인구비례로 설문조사하였다. 평가 결과, 46개 평가항목은 평균 2.46~3.54사이에 분포하고 있었으며, 공공서비스로서 주민에게 제공된 부분보다는 대전광역시의 지리적, 자연적 환경에 관한 변수가 높은 평가를 받아 도시공원녹지에 대해 전체적인 향상이 필요하다고 보여진다. 낮은 평가를 받은 항목은 '주민참여(평균 2.46)', '불편불만건의(평균 2.54)', '주민배려-장애인(평균 2.55)', '공원 녹지 내 다양한 이용프로그램(평균 2.55)', '건의사항의 반영(평균 2.61)'으로 나타나 주민과 함께 계획하고 주민의 의견을 적극 반영하는 과정이 필요한 것으로 판단된다. 또 주민의 주관적 특성에 따라 평가의 차이가 있었으며, 주관적 특성이 만족에 미치는 영향이 크게 나타났다. 따라서 도시공원녹지를 공공서비스적 관점에서 평가함은 새로운 시각이면서 필요한 관점이다. 이것은 그동안 물리적 환경에 대한 만족도 연구만으로는 얻기 어려운 공급결정자, 주민의견반영, 정보이용 등에 대해 접근할 수 있었고, 공급결정자가 만족도에 영향을 준다는 점에서 더욱 공공서비스적 관점에서의 접근이 필요하다. 이러한 주요 인자들에 대한 적극적 반영을 통하여 도시공원과 녹지에 대한 시민들의 만족도를 향상시키기 위한 공무원들의 역할은 증대되어질 것이다.

• Ocean Systems Engineering
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• 제4권3호
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• pp.185-200
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• 2014

The objective of the present simulations is to evaluate the applicability of the standard $k-{\varepsilon}$ turbulence model in engineering practice in the subcritical to supercritical flow regimes. Two-dimensional numerical simulations of flow around a circular cylinder at $Re=1{\times}10^5$, $5{\times}10^5$ and $1{\times}10^6$, had been performed using Unsteady Reynolds-Averaged Navier Stokes (URANS) equations with the standard $k-{\varepsilon}$ turbulence model. Solution verification had been studied by evaluating grid and time step size convergence. For each Reynolds number, several meshes with different grid and time step size resolutions were chosen to calculate the hydrodynamic quantities such as the time-averaged drag coefficient, root-mean square value of lift coefficient, Strouhal number, the coefficient of pressure on the downstream point of the cylinder, the separation angle. By comparing the values of these quantities of adjacent grid or time step size resolutions, convergence study has been performed. Solution validation is obtained by comparing the converged results with published numerical and experimental data. The deviations of the values of present simulated quantities from those corresponding experimental data become smaller as Reynolds numbers increases from $1{\times}10^5$ to $1{\times}10^6$. This may show that the standard $k-{\varepsilon}$ model with enhanced wall treatment appears to be applicable for higher Reynolds number turbulence flow.

• 한국경제지리학회지
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• 제19권2호
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• pp.209-224
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• 2016

본 연구는 지난 10년간 제조업체들이 급격히 유입되고 있는 수도권의 비도시지역의 개별입지 제조업체들의 실태와 그 특성을 파악하고, 이로 인해 나타나는 문제점을 도출하는데 목적을 두었다. 공장등록통계 원시자료를 이용하여 지난 10년 동안 비도시지역으로 유입된 개별입지 제조업체의 분포 특성을 지도화를 통해 분석하였다. 그 결과 약 90%의 제조업체들은 서울과 인접한 일부 10개 지역으로만 군집하고 있으며, 유입된 제조업종들은 지역별로 상당한 차이를 보이고 있다. 가장 많은 제조업체가 유입된 화성시 장안면을 대상으로 설문조사와 현지조사를 수행한 결과 제조업체들이 무분별하게 비도시지역에 입지하면서 농촌 마을의 토지이용 및 환경오염 및 농촌 마을 공동체에 부정적 영향을 주는 것으로 나타났다. 본 연구 결과는 수도권 비도시지역의 바람직한 산업입지 정책을 수립하는데 필요한 시사점을 제공하였다.

• 한국전통조경학회지
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• 제41권2호
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• pp.26-34
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• 2023

본 연구는 경복궁 후원의 경관을 보존·관리·활용하는 데 필요한 기초적인 정보를 제공하고자 전·현직 청와대 조경 관리자를 대상으로 인터뷰를 시행하였으며, 요약된 주요 결론은 다음과 같다. 첫째, 경복궁 후원의 지형은 노태우 대통령 당시 본관과 관저를 신축하며 절토와 성토가 이루어지며 많은 변화가 있었다. 수계는 과거 경복궁과 연결되어 있었으나 현재는 단절된 상태이다. 둘째, 식재의 경우 가장 중요한 원칙은 대통령의 경호와 의전이었으며 이에 따라 수목이 배치되거나 관리되었다. 수목은 여러 지방에서 우수한 수목들을 도입하여 심었으며, 야생화와 지피식물들도 계절에 따라 자주 교체하였다. 셋째, 시설물 및 동선은 점경물과 휴게시설 등이 대통령의 의전이나 취미, 근무자들의 휴식을 위해 배치되었으며, 백악산 산림지역의 방재를 위해 소방시설을 설치하였다. 넷째, 청와대 시기 경복궁 후원 조경의 가장 큰 변곡점은 노태우 대통령 시절 본관과 관저 신축으로 인한 지형의 변화, 노무현 대통령 시절 공간을 분리하던 A, B 철책의 제거 그리고 이명박 대통령 시절 G20 정상회의를 위해 수행된 대대적인 공간 정비로 파악된다. 경복궁 후원 영역이 2022년 5월 10일 시행된 청와대 국민 개방으로 인해 또 다른 변곡점을 맞을 것으로 예상되며, 현황을 잘 보존하면서 경복궁 후원이 가진 역사적·학술적·경관적 가치를 평가하는 작업이 시행되어야 할 것이다.

• 대한조선학회논문집
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• 제43권5호
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• pp.604-610
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• 2006

Common structural rules of JBP(Joint Bulker Project) and JTP(Joint Tanker Project), which will come into effect in 2006, invoke the necessity of the ultimate limit state(ULS) design for ship structures. Even though the many applications of ULS analysis have been performed for ship structures, there have few studies carried out for deck machineries and their supporting structures. Recently four major Korean shipbuilders(DSME, HHI, HHIC, SHI) jointly developed and proposed a new design standards for mooring fittings and also proposed the SWL (Safety Working Load) obtained based on the first yield criterion. In this study, various ultimate strength analyses were performed for bollards and their foundation structures whose yield strengths were quantified by the research consortium. Prior to performing the ultimate strength analyses, the numerical calculation method was substantiated with the test results provided in the joint work report. Based upon the results of this study, it can be concluded that the reinforcements to increase the yield strength are not always resulted in the enhancement of the ultimate strength. Furthermore, the additional production costs for the reinforcements can not be rewarded by the ultimate strength. Therefore, another alternative arrangements should be developed in the view point of ultimate strength.

• The Korean Journal of Pain
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• 제14권1호
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• pp.51-55
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• 2001

Background: Oral mucositis is a common complication of anticancer chemotherapy. The sequelae of this consist of an increased risk of infection, moderate to severe pain, compromised oral function, and bleeding. This study was performed to evaluated the effects of the He-Ne laser and the Ga-Al-As laser on oral mucositis caused by anticancer chemotherapy in pediatric patients. Methods: There were 3 cases of osteosarcoma and 6 cases of leukemia. All patients received He-Ne laser (632.8 nm wavelength, power 60 mW) application on 400-600 Hz scanning for 5-20 minutes and Ga-Al-As laser (904 nm wavelength, power 40 mW) application by fiberoptic hand piece placed in immediate proximity to the tissue without direct contact with it for 30 seconds per point for 5 days per week. During the application patients wore wavelength-specific dark glasses and were instructed to keep their eyes closed. Results: The mean number of treatments with oral intake was $4.89{\pm}0.64$. The mean number of total treatments was $9.44{\pm}2.59$. There were no significant side effects during and after the laser treatments. Conclusions: He-Ne laser and Ga-Al-As (IR) laser treatment were well tolerated and reduced the severity and duration of chemotherapy-induced oral mucositis in pediatric oncologic patients.

• Smart Structures and Systems
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• 제21권1호
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• pp.27-35
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• 2018

In the water-filling and preloading test, the sensing cables were installed on the surface of steel spiral case and in the surrounding concrete to monitor the strain distribution of several cross-sections by using Brillouin Optical Time Domain Analysis (BOTDA), a kind of distributed optical fiber sensing (DOFS) technology. The average hoop strain of the spiral case was about $330{\mu}{\varepsilon}$ and $590{\mu}{\varepsilon}$ when the water-filling pressure in the spiral case was 2.6 MPa and 4.1 MPa. The difference between the measured and the calculated strain was only about $50{\mu}{\varepsilon}$. It was the first time that the stress adjustment of the spiral case was monitored by the sensing cable when the pressure was increased to 1 MPa and the residual strain of $20{\mu}{\varepsilon}$ was obtained after preloading. Meanwhile, the shrinkage of $70{\sim}100{\mu}{\varepsilon}$ of the surrounding concrete was effectively monitored during the depressurization. It is estimated that the width of the gap between the steel spiral case and the surrounding concrete was 0.51 ~ 0.75 mm. BOTDA based distributed optical fiber sensing technology can obtain continuous strain of the structure and it is more reliable than traditional point sensor. The strain distribution obtained by BOTDA provides strong support for the design and optimization of the spiral case structure.