• Title/Summary/Keyword: High-strength

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Performance Evaluation of Underground Pipe with In-Situ Recycled Controlled Low Strength Materials (현장발생토사 재활용 유동성채움재를 이용한 지하매설관의 거동평가)

  • Lee Kwan-Ho;Song Chang-Seob
    • International Journal of Highway Engineering
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    • v.8 no.2 s.28
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    • pp.1-12
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    • 2006
  • An existing Steel pipe, Cast iron pipe and Concrete pipe is can not escaped from aging, specially Metal tube is causing many problems that the quality of water worse is concerned about many rust and mike efficient use of preservation of water. The use of Glassfiber Reinforced Plastic Pipe(GRP PIPE) should be one of the possible scheme to get over these problems. The GRP PIPE has an excellent resistance power and the life is lasting from 50 to 100 years roughly. It's to be useful as a result of high durability and a good construction work also it is a light weight therefore can be expected to short the time of construction and man power. In this research, to executed the small-scaled model test, in-situ model test using CLSM of in-situ soil and to evaluated the stress - strain of the pipe also try to estimated how useful is. From the model test in laboratory, the vertical and horizontal deformation of the GRP PIPE measured in six instance using 200mm and 300mm in diameters. The value of experimentation, theory, analysis got the same results of the test, but the vertical and horizontal deformation gauged in small and the earth pressure was almost zero using CLSM of in-situ soil..

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The Classification and Regional Development's Direction of Rural Fishing Area Based on Administrative District (행정구역에 기초한 어촌지역의 유형구분과 지역개발방향)

  • Kim, Jung-Tae
    • Journal of Korean Society of Rural Planning
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    • v.19 no.4
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    • pp.81-93
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    • 2013
  • The selection of land for fishing village development project, and the standard used to classify fishing villages has been determined based on the guidelines developed by fishing village cooperatives. The approach fishing village cooperatives follows is likely to classify fishing villages without first reflecting on the overall development environment of the region, such as other industries and workers in the area. It also acts as a barrier for business promotion or evaluation, because the cooperatives do not match the administrative districts, which are the units of administration, and the main policy enforcement agent in regional development. Against this background, this study aimed to identify categories to situate the development direction, as well as the size and distribution of fishing villages based on eup, myeon, and dong administrative units as defined by the Fishing Villages and Fishery Harbors Act. This study was based on the Census of Agriculture, Forestry, and Fisheries of 2010, and analyzed 826 eups, myeon, and dongs with fishery households using the principal component analysis, and 2-Step cluster analysis methods. Therefore, 95% of the variance was explained using the covariance matrix for types of fishing villages, but it was analyzed as one component focusing on the number and ratio of fishery households, and used the cluster-type analysis, which focused on the sizes of fishing villages. The clusters were categorized into three types: (1) the development type based on the number of fishermen in the eups, myeons and dongs was analyzed as village size (682); (2) administrative district size (121); and (3) total eups, myeons and dongs (23), which revealed that the size of most fishing villages was small. We could explain 73% of the variance using the correlation coefficient matrix, which was divided into three types according to the three principal component scores, namely fishery household power, fishery industry power, and fishing village tourism power. Most fishing villages did not have a clear development direction because all business areas within the region were diversified, and 552 regions could be categorized under the harmonious development type, which is in need of balanced development. The fishery industry type typified by industrial strength included 159 regions in need of an approach based on industrialization of fishery product processing. Specialized production areas, which specialized in producing fishery products, were 115 regions with a high percentage of fishermen. The analysis results indicated that various situations in terms of size and development of fishing villages existed. However, because several regions exist in the form of small village units, it was necessary to approach the project in a manner that directed the diversification of regional development projects, such as places for local residents to relax or enjoy tourism experiences within the region, while considering the overall conditions of the relevant eups, myeons, and dongs. Reinforcement of individual support for fishermen based on the Fisheries Act must take precedence over providing support for fishermen through regional development. In addition, it is necessary to approach the development of fishing villages by focusing on industrializing the processing techniques of fishery products. Areas specialized in the production of fishery products are required to consider the facilities for fisheries production, and must make efforts to increase fishery resources, such as releasing fry.

Effective of Body Temperature Increasing during Brain MRI scan (MRI 검사 시 체온상승 효과: 1.5 T vs 3.0 T)

  • Kim, Myeong Seong;Lee, Jongwoong;Jung, Jaeeun
    • Journal of the Korean Society of Radiology
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    • v.11 no.1
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    • pp.49-54
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    • 2017
  • As the Radiofrequency(RF) increases with the magnetic field strength, the wavelength of the RF excitation field becomes smaller, which leads to more the thermal effect in the human-body placed in the electric field. MRI scanner used was GE signa 1.5T, HDx 3.0T and Philips 3.0T with same routine clinical sequence protocol. Therefore temperature was measured before and after each scan. Taken the temperatures in the ear with ear infra-red type thermometer(Braun co). 3.0T were temperature increases more than $0.15^{\circ}C$ and GE 3.0T MRI equipment about $0.14^{\circ}C$ higher than the Philips 3.0T MRI(p<0.012). Psychogenic status was investigated by the survey respondents about their status can not just answer therefore, a little different from the expected. In our study of Thermal effect of clinical MRI with clinical protocol sequence, we found that the 3.0T in the body-temperature rise was greater than the 1.5T. Therefore, in clinical 3.0T examine the dangerous situation caused by the temperature rise occurred (burns, impaired thermoregulatory mechanism in patients with high-temperature damage, exhaustion occurs due to excessive sweating), not to appear the more watched the patient's condition with procedure.

Effect of Si contents on Tensile-Shear Peak Load and Nugget Diameter in the Resistance Spot Welded of Dual Phase Steel for Automotive Body Applications (자동차 차체용 냉연 DP강 저항점용접부의 너깃경과 인장전단강도에 미치는 Si 함유량의 영향)

  • Kong, Jong-Pan;Park, Tae-Jun;Han, Tae-Kyo;Chin, Kwang-Geun;Kang, Chung-Yun
    • Proceedings of the KWS Conference
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    • 2009.11a
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    • pp.45-45
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    • 2009
  • 원가 측면에서 유리한 저항점용접(Resistance Spot Welding)이 차체 용접에 80%이상으로 가장 많이 적용되고 있다. 첨단고강도강(Advanced High Strength Steel)의 저항점용접성 및 용접부 특성에 미치는 공정 변수의 영향에 대한 연구결과는 많으나, 합금원소의 영향에 대해서는 전무하다. 특히, Si는 DP(Dual Phase)강에 첨가 시 균일한 마르텐사이트의 분포를 촉진하는 원소로 저항 점용접성 및 용접부 특성에 영향을 미칠 것으로 예상되며, 이에 대한 연구는 보고된바 없다. 본 연구에서는 냉연 DP강의 저항 점용접시 중요한 인자 중 하나인 너깃경과 전단인장강도에 미치는 Si함유량의 영향을 검토하였다. 사용된 강재 및 용접기는 1.2mm 두께의 Si함유량(0, 0.5, 1.0, 1.5wt%)이 다른 인장강도 780~1000MPa급 냉연 DP강과 단상 AC용접기를 사용하였다. 용접조건은 ISO 18278-2규격에 따라 가압력 4kA, 초기가압시간 40cycle, 유지시간 17cycle로 고정하고, 용접전류만 변화하여 용접을 실시하였다. 너깃경은 용접부 단면을 컷팅 후 폴리싱 하여, 광학현미경과 Image Pro plus를 이용하여 측정했으며, 인장시편규격은 JIS Z 3137를 이용하였다. Si함유량이 증가에 따라 스패터 발생 전류는 감소했고, 너깃경은 직선적으로 증가했다. Si함유량 증가에 따른 너깃경 증가 이유는 저항(R) 측정결과, Si함유량 증가에 따라 모재의 저항이 높아져, 따라서 입열량($Q=I^2Rt$)이 많아지기 때문으로 판단되었다. 인정전단강도는 Si함유량 증가에 따라 직선적으로 증가했다. 이러한 이유는 Si함유량 증가에 따라 너깃경이 증가되기 때문으로 판단되었고, 너깃경과 인장전단강도 사이에 직선적 관계(PL(kN)=$3.2N_{dia.}$-0.81, $R^2$=0.93)를 가지고 있었다. 파단양상은 Si함유량에 상관없이 5.4kA이하에서는 계면파단이 일어났고, 6.0kA이상에서는 풀 아웃 파단이 일어났다. 계면파단주원인은 용접부 가장자리에 지름이 약 $5{\mu}m$이하의 예리한 노치가 존재하여 노치응력집중과 HAZ계면 근처에 미접합부가 존재하기 때문으로 판단되었다. 6.0kA이상에서는 예리한 노치가 없었고, HAZ부가 완전히 접합되어 있기 때문에 풀 아웃 파단이 일어난 것으로 판단되었다. 따라서, Si함유량 증가에 따라 적정용접전류 구간은 감소했고, 너깃경은 직선적으로 증가했다. 또한, Si함유량 증가에 따라 인장전간강도는 증가 했으며, 너깃경과 인장전단강도 사이에 직선적 관계를 가지고 있었다. 파단 양상은 Si함유량에 상관없이 5.2kA이하에서는 계면파단이, 6.0kA이상에서는 풀 아웃 파단이 일어났다.

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Effect of Oxide Film Formation on the Fatigue Behavior of Aluminum Alloy (알루미늄합금 재료의 산화막 형성이 피로거동에 미치는 영향)

  • Kim, Jong-Cheon;Cheong, Seong-Kyun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.4
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    • pp.421-428
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    • 2012
  • In this study, the effects of surface oxide film formation on the fatigue behavior of 7075-T6 aluminum alloy were analyzed in terms of the corrosion time of the alloy. The aluminum material used is known to have high corrosion resistance due to the passivation phenomenon that prevents corrosion. Aluminum alloys have been widely used in various industrial applications such as aircraft component manufacturing because of their lighter weight and higher strength than other materials. Therefore, studies on the fatigue behavior of materials and passivation properties that prevent corrosion are required. The fatigue behavior in terms of the corrosion time was analyzed by using a four-pointing bending machine, and the surface corrosion level of the aluminum material in terms of the corrosion time was estimated by measuring the surface roughness. In addition, fractographic analysis was performed and the oxide films formed on the material surface were studied by scanning electron microscopy (SEM). The results indicated that corrosion actively progressed for four weeks during the initial corrosion phase, the fatigue life significantly decreased, and the surface roughness increased. However, after four weeks, the corrosion reaction tended to slow down due to the passivation phenomenon of the material. Therefore, on the basis of SEM analysis results, it was concluded that the growth of the surface oxide film was reduced after four weeks and then the oxide film on the material surface served as a protection layer and prevented further corrosion.

Study on VHCF Fatigue Behaviors and UNSM Effects of Hydrogen Attacked STS 316L (수소취화된 스테인리스강 316L의 VHCF(Very High Cycle Fatigue) 피로특성과 UNSM 효과에 관한 연구)

  • Nahm, Seung-Hoon;Baek, Un-Bong;Suh, Chang-Min;Pyun, Young-Sik
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.11
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    • pp.1011-1020
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    • 2017
  • This study was conducted to investigate the material properties of stainless steel 316L specimens of untreated and UNSM treated material, hydrogen attacked material(100 bar, $300^{\circ}C$ at 120 h) and UNSM treated hydrogen attacked material at room temperature. Results demonstrated that the hydrogen attacked materials showed a tendency toward a slightly decreased fatigue strength, while the hydrogen embrittlement effect was smaller than the S-N curve of conventional untreated material. As compared to untreated material, the fatigue limit of the UNSM treated material increased by 43.8%, while it was 57.1% higher in the UNSM treated hydrogen attacked material than in untreated hydrogen attacked material. The plastic deformation layer was ${\sim}152{\mu}m$ thick, as confirmed by maps showing the level of local plastic deformation affected by the UNSM treatment in three ways: an image quality map, inverse pole figure map, and kernel average misorientation map captured via electron back scatter diffraction. Owing to hydrogen embrittlement, about 90% of surface cracks were smaller than the average grain size of $35{\mu}m$.

Resistance to Weathering with Materials for fisheries Facilities 1. Photodegradation Mechanisms of Netting Twines for Fisheries Facilities (수산시설용 재료의 내후성에 관한 연구 1.그물실의 자외선 열화기구)

  • 김태호
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.36 no.1
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    • pp.45-53
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    • 2000
  • To analyze the photodegradation mechanism of materials for fisheries facilities which stand for considerable time immediately under or even partly above the water surface, such as cage collar, cage net, stationary fishing gear, egc. after 900 hours exposure, weathering experiments on 3 kinds of netting twines like dyed polyethylene(PE) and nylon, and non-treated high strength PE(Hi-PE) were carried out by using xenon light source. The results obtained are as follows : It was observed by scanning electron micrograph(SEM) that a good protection by pigments was obtained in PE and nylon specimen, while crack was rapidly progressed at the surface of Hi-PE one owing to etching by UVR. There was a little increase in density resulting from reorientation of polymer chain, chain scission, etc. in Hi-PE specimen. A wide angle X-ray diffraction showed that 3 kinds of specimens had no fundamental changes in polymer crystalline structure considering each 2$\theta$ of diffraction peak. Remaining tenacity of netting twines was in order of PE, nylon, and Hi-PE after having been exposed to the effect of 900 hours. PE and nylon treated with stuffs were shown to be more resilient than non-treated Hi-PE as confirmed by SEM.

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A Case Report on Panic Disorder Patient Using the 'MRM (Mentalizing the Rooms of Mind)' and Korean Medicine Therapy (한의치료와 '마음의 방 그리기'를 활용한 공황장애 치험 1례 보고)

  • Kim, Jeesu;Cheong, Moon Joo;Lee, Ga-Won;Lyu, Yeoung-Su;Kang, Hyung Won
    • Journal of Oriental Neuropsychiatry
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    • v.31 no.3
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    • pp.197-211
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    • 2020
  • Objectives: The purpose of this study was to introduce the progress of treatment and improve clinical use after conducting Mentalizing the Rooms of Mind, the main technique of Mindfulness & Loving Beingness psychotherapy, for a patient with panic disorder. Methods: We conducted a Mentalizing the Rooms of Mind for 10 sessions on an age 23 female diagnosed with panic disorder based on the DSM-5 diagnostic criteria. After receiving consent from the subject, through chart review, the progress of treatment was observed focusing on the MMPI-2 and CSEI-s (The Core Seven Emotions Inventory-short form) conducted pre- and post-treatment. This study was approved by the Institutional Review Board of Wonkwang University Sanbon Hospital (WMCSB202007-55). Results: 1. The MMPI-2 clinical scales of an age 23 female with panic disorder showed a 7 (Pt)-1 (Hs)-3 (Hy) profile pre-treatment, but for post-treatment, the scale showed 1 (Hs)-3 (Hy) profile, and the 7 (Pt) scale showed significant decline. In the MMPI-2 reconstructed clinical scales, RC7 (Dysfunctional Negative Emotions) and RC8 (Aberrant Experiences) showed significant decline. 2. In the pre- and post-treatment MMPI-2 content scales, Anxiety, Fears, Obsessiveness, Social Discomfort, and Work Interference scores decreased, showing overall positive stability. On the MMPI-2 supplementary scales, the Anxiety and Post-Traumatic Stress Disorder scores decreased, and the Ego Strength increased, resulting in improved overall psychological adaptation. 3. Pre- and post-treatment of an age 23 female with panic disorder, CSEI-s showed significant decline of 恐, 驚, 悲, and 思. So it seems that the emotions caused by Chiljeongsang (七情傷) were more stable than before treatment. Conclusions: As shown above, the treatment of panic disorder through Mentalizing the Rooms of Mind, a major technique of Mindfulness & Loving Beingness psychotherapy, showed positive changes in MMPI-2 as well as improvement of the subjective symptoms. Thus, Mentalizing the Rooms of Mind has high clinical use, and it seems that it is necessary to create a manual for this in the future.

Survey on the Use and Perception of Health Functional Foods and Herbal Medicine for Children in Local Day Care Center - Focus on Wonju and Chungju Region - (어린이집 아동의 건강기능식품 이용실태와 한약이용에 대한 인식 - 원주와 충주의 일부 어린이집을 대상으로 -)

  • Sung, Hyun-Kyung;Min, Deul-Le;Park, Su-Jung;Sung, Angela Dongmin;Lee, Sundong;Park, Haemo
    • Journal of Society of Preventive Korean Medicine
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    • v.21 no.2
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    • pp.117-126
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    • 2017
  • Objectives : The use of health functional foods is gradually increasing. On the other hand, the use of the Korean herbal medicine is gradually decreasing. Especially children are known to have a high percentage of taking a health functional food. This study was designed to compare the use of health functional food with the reason for taking the Korean herbal medicine. Methods : The participants were 453 parents who have kids age between 3 to 6 years old from day care center in Wonju and Chungju. The questionnaire consisted of 17 questions and the survey was conducted by self-entry method. This study analyzed 374 participants' questionnaires who agreed to the survey. Results : The percentages of children's health functional food intake experience were 82.9% and they usually bought products which contain lactic acid bacteria(55.6%). The reason for consuming health functional food was to strengthen the immune system and enhance the physical strength. Most of the participants purchased health functional food from pharmacy through inaccurate information such as the internet. The percentages of children's health functional food preference were 58.5% because it is easy to take. The percentages of children's herbal medicine preference were 41.7%. There are inconveniences of taking herbal medicine because of taste and smell(68.8%). Conclusions : Therefore, it is necessary to change the formulation of the herbal medicine and increase convenience for use of the herbal medicine to preschooler(3-6 years old). In additionary, it is necessary to supply accurate and up to date information of herbal medicine taking.

Associations of Low Environmental Exposure to Multiple Metals with Renal Tubular Impairment in Korean Adults

  • Lim, Hyungryul;Lim, Ji-ae;Choi, Jong Hyuk;Kwon, Ho-jang;Ha, Mina;Kim, Heon;Park, Jung-duck
    • Toxicological Research
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    • v.32 no.1
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    • pp.57-64
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    • 2016
  • Recently several studies reported that the renal toxicity of lead (Pb) and cadmium (Cd) may exist in even a low level exposure. In terms of the deterioration of tubular function, it affects the loss of divalent metals and leads to other complications, so renal tubular effect of heavy metals should be well managed. Considering the exposure to heavy metals in reality, it is hard to find the case that human is exposed to only one heavy metal. We designed a cross-sectional study using Korean Research Project on the Integrated Exposure Assessment (KRIEFS) data to investigate the renal effects of multiple metal exposure in general population. We used blood Pb and urinary Cd as exposure measures, and urinary N-acetyl-${\beta}$-D-glucosaminidase (NAG) and ${\beta}_2$-microglobulin (${\beta}_2$-MG) as renal tubular impairment outcome. We conducted linear regression to identify the association between each heavy metal and urinary NAG and ${\beta}_2$-MG. And then, we conducted linear regression including the interaction term. Of 1953 adults in KRIEFS (2010~2011), the geometric mean of blood Pb and urinary Cd concentration was $2.21{\mu}g/dL$ (geometric $SD=1.49{\mu}g/dL$) and $1.08{\mu}g/g\;cr$ (geometric $SD=1.98{\mu}g/g\;cr$), respectively. In urinary Cd, the strength of the association was also high after adjusting (urinary NAG: ${\beta}=0.44$, p < 0.001; urinary ${\beta}_2$-MG: ${\beta}=0.13$, p = 0.002). Finally, we identified the positive interactions for the two renal biomarkers. The interaction effect of the two heavy metals of ${\beta}_2$-MG was greater than that of NAG. It is very important in public health perspective if the low level exposure to multiple heavy metals has an interaction effect on kidney. More epidemiological studies for the interaction and toxicological studies on the mechanism are needed.