• Title/Summary/Keyword: Drop analysis

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연안해역에서 비선형 조석으로 인한 해수면 변화 (Sea Level Change due to Nonlinear Tides in Coastal Region)

  • 정태성
    • 한국해안·해양공학회논문집
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    • 제29권5호
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    • pp.228-238
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    • 2017
  • 우리나라 연안해역에서 조사된 조위 조화상수를 수집하여 조석 분포와 비선형 조석특성의 분포를 조사하고, 국립해양조사원에서 관측한 목포항과 군산외항의 조위자료를 조화분석하여 비선형 조석의 경년변화와 비조화상수(고조위, 저조위, 조차)의 경년변화의 관련성을 검토하였다. 비선형 조석의 발생과 조석형태수가 관련성이 있음을 확인할 수 있었으며, 비선형 분조의 변화는 고조위와 저조위의 변화에 큰 영향을 주었다. 목포항에서는 해안개발로 인해서 비선형 분조의 진폭과 위상이 크게 변화하고, 이로 인해서 고조위가 상승하고, 저조위는 하강하여 조차가 증가하였다. 군산외항에서는 새만금방조제 준공이후에 비선형 조석의 영향으로 고조위는 하강하고, 저조위는 상승하여 조차가 감소하였다.

전기비저항 물성 분석을 통한 제체의 안정성 검토 (Safety Assessment of Embankment by Analysis of Electrical Properties)

  • 오석훈;서백수
    • 지질공학
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    • 제18권3호
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    • pp.245-255
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    • 2008
  • 제체의 안전진단을 위해 많이 적용되고 있는 전기비저항 탐사 자료 해석의 효율성을 높이기 위해, 제체의 상태에 따른 전기비저항 물성의 변화 양상을 실내시험 및 실측 자료의 분석을 통해 파악하였다. 이를 위해 제체의 심벽 재료와 유사한 성질을 가지는 kaolinite를 이용하여 압밀조건에 따른 비저항 변화를 살펴보았다. 그 결과, 일축 압축에 의하여 전단강도가 떨어지는 경우에는 함수량에 관계없이 비저항 값이 상승하는 것으로 나타났다. 이러한 사실은 제체 내의 심벽부분에 공극이 크게 발달하는 경우, 함수량에 상관없이 비저항은 상승할 가능성이 있다는 것이다. 코어부의 누수 현상과 관련한 이러한 관측은, 단순히 비저항이 낮은 곳만을 탐지하는 것이 누수대역을 조사하는데 있어 목표가 되어서는 안 된다는 것을 암시한다. 또한 전기비저항 물성이 지반 강성도와 갖는 상관성을 파악하기 위해, 제체에 대한 시추를 통해 표준관입시험을 수행하였다. 마지막으로, 제체 보강을 위해 수행된 그라우팅 효과의 검증을 위해, 그라우팅에 따른 비저항변이 알고리듬을 제안하고, 실제 관측 자료와의 비교를 통해 알고리듬을 파악하였다.

노년 여성 기성복 치수분석 뫼 체형별 맞음새에 관한 연구 (Size Analysis of Ready-made Clothing for Elderly Women and Fit Evaluation according to their Body Type)

  • 이정임;주소영
    • 한국의류학회지
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    • 제29권8호
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    • pp.1092-1101
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    • 2005
  • The purpose of this study is to analyze the size of ready-made clothing for elderly women and to evaluate their fit according to body type. Subjects were 33 women aged 60 and older, and they were classified by stature and drop index. The size of clothing which manufactured by four apparel brands were measured and compared with body size, and the size designation of four brands was compared. The questionnaire was carried out to subjects, and the size recognition and dissatisfaction with ready-made clothing were analyzed. The fitting test were carried out, and the subjects evaluated the fit of jackets and slacks of four brands. In the result of questionnaire, we found that subjects had little recognition about their clothing size. Subjects responded that they often felt dissatisfaction in their jacket length, sleeve length, shoulder width, bust girth, slacks, and waist girth. We found that each apparel brands had different sizing system and that even if the size designation of label was same, the clothing size was quite different. So the elderly women who didn't have so much knowledge about their own clothing size had a tendency to confuse with choosing proper clothing for themselves. In the wearer's evaluation, the significant difference in the degree of unsatisfaction were certified in several body parts according to wearer's body type. Especially, the degree of unsatisfaction in the case of subjects of having very small stature or very small hip was higher than other body types. From the result, we certified that it was necessary to consider the characteristics of each body type to increase the satisfaction of elderly women with clothing.

PV 모듈 내 바이패스 다이오드 손상에 의한 열적 전기적 특성 변화 분석 (Analysis on thermal & electrical characteristics variation of PV module with damaged bypass diodes)

  • 신우균;정태희;고석환;주영철;장효식;강기환
    • 한국태양에너지학회 논문집
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    • 제35권4호
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    • pp.67-75
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    • 2015
  • PV module is conventionally connected in series with some solar cell to adjust the output of module. Some bypass diodes in module are installed to prevent module from hot spot and mismatch power loss. However, bypass diode in module exposed outdoor is easily damaged by surge voltage. In this paper, we study the thermal and electrical characteristics change of module with damaged bypass diode to easily find module with damaged bypass diode in photovoltaic system consisting of many modules. Firstly, the temperature change of bypass diode is measured according to forward and reverse bias current flowing through bypass diode. The maximum surface temperature of damaged bypass diode applied reverse bias is higher than that of normal bypass diode despite flowing equal current. Also, the output change of module with and without damaged bypass diode is observed. The output of module with damaged bypass diode is proportionally reduced by the total number of connected solar cells per one bypass diode. Lastly, the distribution temperature of module with damaged bypass diode is confirmed by IR camera. Temperature of all solar cells connected with damaged bypass diode rises and even hot spot of some solar cells is observed. We confirm that damaged bypass diodes in module lead to power drop of module, temperature rise of module and temperature rise of bypass diode. Those results are used to find module with a damaged bypass diode in system.

a-Si 태양전지 모듈의 hotspot에 의한 열화현상 연구 (Analysis of degradation by hotspot heating in amorphous silicon PV module)

  • 윤나리;정태희;민용기;강기환;안형근;한득영
    • 한국태양에너지학회:학술대회논문집
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    • 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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    • pp.17-22
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    • 2011
  • There are some degradation factors for amorphous silicon solar cells. Light inducing is one of the factor that explained by Staebler-Wronski effect. Also, hotspot heating could be the reason that makes amorphous silicon solar cell degrade. Hotspot heating is occurred when a solar cell is shaded so this work is investigated into two types of shading condition and how these affect to solar cell differently. Reduced irradiance for whole cell and partially shaded as 0($W/m^2$) while the other part of cell is soaking as 1000($W/m^2$) of irradiance are two conditions that are experimented. The two types of shading show different characteristics of degradations. The result shows that partially shaded cell dropped maximum powerless and slower. Also sudden drop points have shown that should be concerned to decide the number of cells for a string. Otherwise, the current through a shaded cell might flow more than cell's capability. It makes cell and module damaged. This work would help to manufacture modules.

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HCFC-22 대체냉매의 모세관 선정 (Selection of Capillary Tubes for HCFC-22 Alternative Fluids)

  • 정동수;김종보
    • 설비공학논문집
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    • 제7권3호
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    • pp.435-449
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    • 1995
  • In this paper, pressure drop through a capillary tube is modeled to determine the length of a capillary tube for a given set of conditions. HCFC-22 and its alternatives, HFC-134a, R407B, and R410A are used as working fluids. The conditions on which the model is tested are as follows : condensing temperature; 40.0, 45.0, 50.0, $55.0^{\circ}C$, degree of subcooling;0.0, 2.5, $5.0^{\circ}C$, capillary tube exit condition;choked flow, capillary tube diameter;1.2~2.4mm, mass flow rate;5.0~50.0g/sec. The results justify the use of Stoecker's model which yields the results very close to the values in ASHRAE handbook. While McAdams' method yields much better results than Duckler's in calculating the viscosity of the fluid in 2-phase, the friction factor suggested by Stoecker seems to be the best for capillary tubes of large diameter used in residential air conditioners. For each refrigerant, 372 data with various variables are calculated by the model. The results show that capillary tube length varies very uniformly with changes in condensing temperature and degree of subcooling. Based on this fact, regression analysis is performed to determine the dependence of mass flow rate on the length and diameter of a capillary tube, condensing temperature, and degree of subcooling. Thus determined correlation yields a mean deviation of 2.36% for 1,488 data, showing an excellent agreement.

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관절염 환자의 자기효능, 집단응집력, 가족지지가 수중운동프로그램 지속에 미치는 영향 (The Effect of the Self-efficacy, Group Cohesion, Family Support on Adherence of Aquatic Exercise in Arthritis Patients)

  • 김정연;김종임
    • 근관절건강학회지
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    • 제10권1호
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    • pp.19-31
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    • 2003
  • Purpose : The purpose of this study was to examine the effect of the self- efficacy, group cohesion and family support on adherence of aquatic exercise in arthritis patients. Method : The Subjects were 30 patients with arthritis who had participated in the 6-week aquatic exercise programs of Korean Rheumatology Health Professionals Society. All subjects were interviewed from November to December, 2001(1st) and Feburary, 2002(2nd) using a structured questionnaire which was composed of 42 items. SPSS Win 10.0 was used for data analysis. Results : Ten out of thirty were adherer who were keeping aquatic exercise for three months since they completed 6-week aquatic exercise program. The major reasons of adherence were affectional reasons and general condition improvement on the first month. The reasons of 3-month adherence were improvement of arthritis symptoms, affectional improvement, expectations, general condition improvement and group activity. The major reasons of drop out were environment factors and physical factors. The environmental reason were time shortage, economic problem and long distance. And the physical factor were cold, pain and other health problem. The scores of self-efficacy were decreased from 528.00 to 476.00 within 3 months after compeleting aquatic exercise program and that was statistically significant(p=.029). But there were no statistically differences in group cohesion and family support. There was a significant positive correlation between exercise adherence and self-efficacy. Factors influencing the exercise adherence was self-efficacy which accounted for 23% of the variance in the exercise adherence. Conclusion : In conclusion, self-efficacy is a significant variable in the exercise adherence and changes within 3 month after completing aquatic exercise program. The results of this study suggested that the strategy for maintaining self-efficacy should be developed.

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성형직후 건조환경이 시멘트 모르터의 강도에 미치는 영향 (The Effect of Dry Environment on Strength of Cement Mortar Immediately after Casting)

  • 오무영;김준희
    • 한국농공학회지
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    • 제33권2호
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    • pp.61-72
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    • 1991
  • This study was carried out to research the strength drop of concrete in dry environment. The mixing ratio of cement-fine aggregate was 1: 1, 1 : 2, 1: 3 and 1 : 4. The curing was compared standard curing with dry curing immediately after casting. It is analysis of strength change by water-proof mixing. The curing age of cement mortar was 3days, 7days, l4days and 28days. The result obtained from this study are summarized as follows. 1. The compressive and bending strength change by increasing the curing age, dry curing mortar the increasing rate of strength was decreased than standard curing mortar. 2. The compressive and bending strength change in early curing, strength difference between standard curing mortar and dry curing motar was gradually closed by increasing the W/C. 3. The dry curing mortar was decreased than standard curing mortar in decreasing rate of compressive and bending strength by increasing the W/C. 4. The compressive strength of water-proof mortar in early curing, liquid water-proof mortar was shown high strength in dry curing than standard curing. The powder and liquid water-proof mortar have a small effect in dry environment. The liquid water-proof mortar was high strength without relation change of curing age in dry environment than standard curing. 5. The compressive strength of liquid water-proof mortar in poverty mix, dry curing was shown high strength than standard curing. 6. The bending strength was increased than compressive strength by decreasing the volume of cement in early curing. The increasing rate of bending strength was decreased to compressive stength by increasing the curing age.

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Roles of Putative Sodium-Hydrogen Antiporter (SHA) Genes in S. coelicolor A3(2) Culture with pH Variation

  • Kim, Yoon-Jung;Moon, Myung-Hee;Lee, Jae-Sun;Hong, Soon-Kwang;Chang, Yong-Keun
    • Journal of Microbiology and Biotechnology
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    • 제21권9호
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    • pp.979-987
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    • 2011
  • Culture pH change has some important roles in signal transduction and secondary metabolism. We have already reported that acidic pH shock enhanced actinorhodin production in Streptomyces coelicolor. Among many potential governing factors on pH variation, the putative $Na^+/H^+$ antiporter (sha) genes in S. coelicolor have been investigated in this study to elucidate the association of the sha on pH variation and secondary metabolism. Through the transcriptional analysis and overexpression experiments on 8 sha genes, we observed that most of the sha expressions were promoted by pH shock, and in the opposite way the pH changes and actinorhodin production were enhanced by the overexpression of each sha. We also confirmed that sha8 especially has a main role in maintaining cell viability and pH homeostasis through $Na^+$ extrusion, in salt effect experiment under the alkaline medium condition by deleting sha8. Moreover, this gene was observed to have a function of pH recovery after pH variation such as the pH shock, being able to cause the sporulation. However, actinorhodin production was not induced by the only pH recovery. The sha8 gene could confer on the host cell the ability to recover pH to the neutral level after pH variation like a pH drop. Sporulation was closely associated with this pH recovery caused by the action of sha8, whereas actinorhodin production was not due to such pH variation patterns alone.

학교 밖 청소년의 문제행동 관련 융복합적 요인: 성별차이를 중심으로 (Convergent Factors Affecting Problem Behaviors in Out-of-school Adolescents: A Focus on Gender Difference)

  • 이재영
    • 디지털융복합연구
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    • 제16권10호
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    • pp.333-342
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    • 2018
  • 본 연구는 학교 밖 청소년을 대상으로 문제행동에 미치는 융복합적 요인을 성별차이를 중심으로 분석하였으며, 부산여성가족개발원에서 실시된 학교 밖 청소년 연구자료를 이용한 이차자료 분석 연구이다. 연구대상자는 총 499명의 학교 밖 청소년이며, 남자는 337명, 여자는 162명이었다. 본 연구에서 조사한 문제행동은 가출, 학업중단, 성매매, 폭력, 인터넷게임중독, 절도, 약물중독 및 흡연이었다. 수집된 자료는 로지스틱 회귀분석으로 분석하였다. 본 연구의 문제행동 중 인터넷게임중독과 절도는 남자 학교 밖 청소년이 여자 학교 밖 청소년보다 높았다. 인터넷게임중독은 남자 학교 밖 청소년이 여자학교 밖 청소년보다 1.90배 높았다(p=.008, 95% CI=1.18-3.06). 절도는 남자 학교 밖 청소년이 여자 학교 밖 청소년보다 1.92배 높았다(p=.006, 95% CI=1.21-3.03). 앞으로 학교 밖 청소년의 문제행동을 예방하고 이에 대한 사회적 대책을 마련할 때, 문제행동의 양상과 성별에 따라 차별화된 접근이 필요하다.