• 제목/요약/키워드: Impact Strength

검색결과 2,130건 처리시간 0.026초

모래 지반 내에 포함된 자갈의 크기가 전단거동에 미치는 영향 (Effect of Gravel Size on Shear Behavior of Sand with Dispersed Gravels)

  • 박성식;김영수
    • 대한토목학회논문집
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    • 제31권1C호
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    • pp.39-51
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    • 2011
  • 작은 입자 사이에 고립된 상태로 존재하는 굵은 입자는 비록 소량일지라도 흙의 전단거동에 영향을 미칠 수 있다. 이와같이 소량의 굵은 자갈이 포함된 지반의 전단특성을 평가할 경우, 실내시험에 사용되는 자갈의 크기와 공시체의 직경이 전단거동에 영향을 미칠 수 있다. 따라서 본 연구에서는 모래 입자 사이에 흩어져 있는 자갈의 크기와 공시체의 직경을 달리하면서 모래-자갈 혼합토의 전단특성을 연구하였다. 크기가 7, 12, 15, 18, 22mm인 다섯 종류의 자갈을 반복 사용하였으며, 각층 높이의 중간부분에 자갈을 넣고 다음 층을 쌓아 다지는 방식으로 조밀한 공시체를 완성하였다. 층당 들어가는 자갈의 크기에 따라 습윤모래를 5층 또는 10층으로 나누어 다져 직경 5cm(높이 10cm) 및 10cm(높이 20cm)인 공시체를 제작하였다. 자갈의 중량비는 3%로 동일하며 세 종류의 구속압으로 압밀시킨 다음, 비배수 삼축압축시험을 실시하였다. 직경 10cm인 공시체에서 얻은 최대축차응력은 직경 5cm인 공시체의 최대축차응력보다 자갈이 없는 경우 평균 30% 정도 높았으며, 자갈이 포함된 경우 최대 90%까지 증가하였다. 7mm와 12mm 자갈이 들어간 경우, 직경이 10cm인 공시체는 자갈의 크기에 관계없이 모두 자갈이 없는 경우보다 최대축차응력이 증가하였으나, 직경이 5cm인 공시체는 자갈의 크기에 따라 최대축차응력이 자갈이 없는 경우보다 증가하거나(7mm 자갈이 들어간 공시체) 또는 감소하였다(12mm 자갈이 들어간 공시체). 공시체 직경과 자갈의 크기가 비배수 전단거동에 큰 영향을 미쳤으며, 자갈과 공시체 직경의 비 1/5을 기준으로 자갈이 포함된 공시체의 최대축차응력이 자갈이 없는 경우보다 증가 또는 감소하였다.

일부지역 치위생 전공 대학생의 외모만족도 및 신체이미지가 대인관계에 미치는 영향 (Impact of Appearance Satisfaction and Body Image on interpersonal Relationship among Dental Hygiene Students in some Regions)

  • 김한홍;김선주
    • 한국콘텐츠학회논문지
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    • 제13권12호
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    • pp.337-347
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    • 2013
  • 본 연구는 치위생을 전공하는 대학생의 외모만족도와 신체이미지가 대인관계에 미치는 영향을 파악하기 위해 실시하였다. 구조화된 설문지를 이용하여 2013년 4월 1일부터 5월 7일까지 치위생(학)과에 재학 중인 학생을 대상으로 자료를 수집하였다. 대상자의 외모만족도 평균은 $2.79{\pm}0.42$점, 신체이미지 평균은 $2.85{\pm}0.53$점, 대인관계능력 평균은 $3.23{\pm}0.48$점으로 나타났다. 대인관계능력은 외모만족도와 그 하위영역인 신체강도 및 신체이미지와 정적 상관관계가 있었고, 대인관계능력에 영향을 미치는 요인으로는 학년(p<0.001), 학제(p=0.005), 임상실습경험(p=0.006), 외모만족도(p=0.003), 신체이미지(p=0.002)로 나타났으며, 이들 변수의 설명력은 35.6%였다. 위의 결과에서와 같이 외모만족도와 신체이미지는 대인관계에 영향을 미치는 요인이므로 바람직한 대인관계를 형성하기 위해서는 자신에 대한 긍정적인 자아개념 형성이 매우 중요하다. 따라서 자신의 외모와 신체이미지에 대해 긍정적이고 올바른 인식을 심어줄 수 있는 다양한 프로그램의 개발과 적용이 필요할 것으로 보인다.

지역사회 노인의 자아통합감에 영향을 미치는 요인 (Converged Factors Influencing Ego Integrity of Community Dwelling Elderly)

  • 김은주;강승주
    • 한국산학기술학회논문지
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    • 제19권8호
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    • pp.160-166
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    • 2018
  • 본 연구의 목적은 노인의 주관적 통증, 주관적 건강, 주관적 행복감, 사회적지지, 자아통합감 정도를 파악하고, 자아통합감에 미치는 요인을 파악하고자 하였다. 연구를 위해 J시의 노인복지관을 이용하는 60세 이상 노인 250명을 대상으로 자료를 수집하여 분석하였다. 연구 자료는 기술통계, t-test, ANOVA, Pearson's Correlation Coefficient, multiple regression analysis를 이용하여 분석하였다. 결과, 첫째, 일반적 특성 중 경제능력만 영향을 미치는 것으로 나타났다. 둘째, 노인의 자아통합감과 주관적 통증(r=-.187, p=.003), 주관적 건강(r=.231, p<.001), 주관적 행복감(r=.164, p=.009), 사회적 지지(r=.207, p=.001)는 유의한 상관관계가 있는 것으로 나타났다. 셋째, 사회적 지지(${\beta}=.194$, p=.002), 주관적 건강이(${\beta}=.149$, p=.040), 이 자아통합감에 영향력이 있는 것으로 나타났으며 주관적통증과 주관적 행복감은 영향력이 없는 것으로 나타났다. 이들 네 개의 변수가 노인의 자아통합감을 총 10.8% 설명하는 것으로 나타났다. 그러므로, 노년기의 과업이며 성공적 노화인 자아통합감을 이룰 수 있도록 하기 위해서 노인의 사회적 지지를 향상시키고, 주관적 건강상태를 향상시키기 위한 노인의 중재 프로그램 개발이 필요하다.

Efficacy of a Training Program for Long-Term Disease-Free Cancer Survivors as Health Partners: A Randomized Controlled Trial in Korea

  • Yun, Young Ho;Lee, Myung Kyung;Bae, Yeonmin;Shon, Eun-Jung;Shin, Bo-Ram;Ko, Hyonsook;Lee, Eun Sook;Noh, Dong-Young;Lim, Jae-Young;Kim, Sung;Kim, Si-Young;Cho, Chi-Heum;Jung, Kyung Hae;Chun, Mison;Lee, Soon Nam;Park, Kyong Hwa;Chang, Yoon Jung
    • Asian Pacific Journal of Cancer Prevention
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    • 제14권12호
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    • pp.7229-7235
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    • 2013
  • Background: To determine whether the Health Partner Program is effective in training long-term cancer survivors to be health coaches. Materials and Methods: We randomly assigned cancer survivors who were selected through a rigorous screening process to either the Health Partner Program or the waiting-list control group. The program consisted of 8 weeks of training in health management, leadership, and coaching. At baseline, 8, and 16 weeks, we measured primary outcomes using the Seven Habit Profile (SHP), the Korean Leadership Coaching Competency Inventory (KCCI), Ed Diner's Satisfaction with Life Scale (SWLS), and the Posttraumatic Growth inventory (PTGI) and secondary outcomes using the Hospital Anxiety and Depression Scale (HADS), the Impact of Event Scale-Revised (IES-R), and the Medical Outcomes Study (MOS) short form 36-item questionnaire (SF-36). Results: We recruited 70 subjects and randomly assigned 34 to the intervention group. The Sharpen the Saw habit of the SHP increased significantly more in intervention group than in the control group (p=0.049), as did most PTGI factors. The intervention group also showed a significantly greater enhancement of vitality (p=0.015) and mental health (p=0.049) SF-36 scores but no improvement in KCCI, SWLS, HADS, or IES-R scores. The intervention group also showed a greater clinically meaningful improvement in the "Think Win-Win" of SHP (p=0.043) and in the personal strength score (p=0.025) and total score (p=0.015) of the PTGI. Conclusions: Long-term cancer survivors can benefit from the Health Partner Program to become health coaches.

2018년 네이버 쇼핑의 고용영향 평가 (Employment Effects Evaluation of Naver Shopping in 2018)

  • 김흥규;정연승
    • 산경연구논집
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    • 제10권5호
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    • pp.27-36
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    • 2019
  • Purpose - Naver has emerged as a new leader in the open market. While existing open markets such as Gmarket, 11th Street, and so on are suffering from profitability deterioration, Naver is attracting sellers based on low commission and powerful search engine. We would like to analyze the impact of Naver shopping on the national economy, especially on employment, in a situation where the market reaction to Naver's strength as a leader in online shopping is mixed. Research Design, Data, and Methodology - Through the demand inducing inter-industry analysis, we estimate the employment inducement effect by Naver shopping from its shopping transaction. In turn, through the supply inducing inter-industry analysis, we estimate the employment inducement effect by Naver shopping from its low commission and powerful search engine. For the purpose of inter-industry analysis, as of 2018, the most recently announced 2014 inter-industry table (extension table) from the Bank of Korea is used. Results - The results of this study are as follows. First, Naver Shopping is expected to generate 7.8 trillion won's trade in 2018, resulting in 244,225 of job inducement, and 158,598 of employment inducement. In addition, Naver Shopping is estimated to benefit KRW 213 billion to its sellers due to low commission and powerful search function, resulting in 8,667 of job inducement, and 5,655 of employment inducement. Second, in terms of job inducement and employment inducement due to Naver Shopping's trade, transportation, business support service, information and communication, broadcasting, restaurants and lodging were ranked. Third, in terms of job inducement and employment inducement due to Naver Shopping's low commission and powerful search function, restaurants and hospitality, f/b and cigarette manufacturing, construction, and transportation equipment manufacturing were ranked. Conclusions - The number of job inducement resulting from low commission and powerful search engine of Naver shopping in 2018 was 8,667 (3.7% of 244,225, which was caused by transaction in Naver shopping in 2018), and employment inducement was 5,655 (3.7% of 158,598, which was caused by transaction in Naver shopping in 2018), which can be considered as additional employment impacts of Naver Shopping compared to the other online shopping operators.

학교급식의 관리와 효과에 대한 초등교사들의 태도 분석 (Analysis of Elementary School Teachers' Attitude Toward School Food Service Management and Effect)

  • 김학현
    • 한국학교ㆍ지역보건교육학회지
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    • 제1권1호
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    • pp.61-82
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    • 2000
  • The purpose of this study was to find out the general problems of school food service and to explore a way to improve it, by examining elementary school teacher's consciousness and attitude toward it that gave a big impact on children's development of food habit. For attaining the purpose, the following research questions were posed : 1) What's elementary school teacher attitude toward school food service management? 2) What's elementary school teacher attitude toward school food service effect on children? 3) What's elementary school teacher opinion about how to develop school food service? The subjects of study were 328 male or female teachers who served at elementary school in urban and rural area, including eup, myon, or farming and fishing villages, Kyonggi province. A questionnaire survey was conducted over them. The conclusions were as follows: 1) Teacher Attitude Toward School Food Service Management Concerning food service place, the subjects were more satisfied at food service room(73.3%) than at classroom(23.0%). They responded that food service room was more effective, than classroom, for food transportation, distribution and post-arrangement. Their satisfaction at food service place was significantly different. The older teachers considered personnel management and cooking room's sanitary management to be more efficient, and their age made a significant difference to their consciousness of these things. Many teachers(63.1%) thought the measures to prevent and manage group food poisoning were relatively efficient. The male teachers expressed more affirmative view on the efficiency of school food expense management and menu preparation than female teachers, and there was a significant disparity between male and female teachers. 2) Elementary School Food Service Effect School food service was thought to be very effective for physical growth(74.1%) and physical strength improvement(70.1%). Teachers at smaller school revealed more affirmative response toward school food service effect on correcting an unbalanced diet, and older teachers considered its effect on nutrition knowledge acquisition and learning outcome to be more great. Teachers at larger school put less value on its effect on table manners, and school size produced a significant difference. The number of teachers who thought school food service generally raised parent concern and support for school(36.6%) was a little more than that of teachers who didn't think so(15.2%). And the number of teachers who didn't consider its effect on improving parent food life to be good(29.3%) was slightly more than that of teachers who did. 3) School Food Service Reform Measure What's most urgently needed for better school food service management appeared to be an expansion of facilities concerned, followed by more effective food distribution and transport, cooking room's better sanitary management, more successful food poisoning prevention and management, more effective food expense management, and an increase of food service personnel in the order named. The most effective means of school food service education was found to be a creation of link system to family, followed by a development of school food service education program, a development of teaching materials, an insertion of school food service in curriculum, and teacher education in the order named.

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Prognostic Value of Matrix Metalloproteinase 9 Expression in Breast Cancer Patients: A Meta-analysis

  • Song, Jian;Su, Hong;Zhou, Yang-Yang;Guo, Liang-Liang
    • Asian Pacific Journal of Cancer Prevention
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    • 제14권3호
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    • pp.1615-1621
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    • 2013
  • Background: Matrix metalloproteinase 9 (MMP-9) is related to tumor invasion and metastasis. However, the role of MMP-9 expression in breast cancer survival remains controversial. The purpose of this study was to accomplish a more accurate estimation of the association between MMP-9 expression and survival results in breast cancer patients through meta-analysis. Methods: A meta-analysis of published studies investigating the effects of positive MMP-9 expression on both relapse free survival (RFS) and overall survival (OS) was performed. Relevant literature was confirmed by searching electronic databases including PubMed, Ovid, EMBASE and China National Knowledge Infrastructure (CNKI) before November 1, 2012. Individual hazard ratios (HRs) and 95% confidence intervals (CIs) were extracted and pooled HRs with 95% CIs were used to evaluate the strength of the association between positive MMP-9 expression and survival results of breast cancer patients. Funnel plot and Egger's regression tests were used to evaluate publication bias. Heterogeneity and sensitivity analysis was also conducted. All the work was completed using STATA. Results: A total of 2,344 patients from 15 evaluative studies were finally included. Pooled HRs and 95% CIs suggested that MMP-9 overexpression had an unfavorable impact on both OS (HR: 1.70, 95% CI: 1.41-2.04) and RFS (HR: 1.54, 95% CI: 1.17-2.01) in breast cancer patients. There was no significant heterogeneity observed in the studies reported for OS (P=0.360, $I^2$=8.8%), but not RFS (P=0.002, $I^2$=67%). Publication bias was absent among the studies both in OS and RFS cases (t=-0.54, P=0.605 and t=1.71, P=0.131, respectively). Omission of any single study had little effect on the combined risk estimates on sensitivity analysis. Conclusion: The results of this meta-analysis suggest that positive MMP-9 expression confers a higher risk of relapse and a worse survival in patients with breast cancer. Larger prospective studies are now needed to evaluate the clinical utility of MMP-9 expression.

시공하중 및 균열 효과를 고려한 플랫 플레이트의 처짐 산정 (Calculations of Flat Plate Deflections Considering Effects of Construction Loads and Cracking)

  • 김재요;임주혁;박홍근
    • 콘크리트학회논문집
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    • 제21권6호
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    • pp.797-804
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    • 2009
  • 테두리 보에 의한 휨강성이 확보되지 않은 철근콘크리트 플랫 플레이트의 구조설계는 강도 조건 뿐만 아니라 사용성에 의하여 지배받을 수 있다. 특히, 조기 재령 슬래브의 과하중 작용 및 균열 발생은 시공 중인 플랫 플레이트의 처짐을 크게 증가시키므로, 시공 순서 및 슬래브 처짐에 대한 영향은 플랫 플레이트 시스템 설계의 주요한 요소가 될 수 있다. 이 연구에서는 시공 순서 및 콘크리트 균열 효과를 고려한 슬래브 처짐 산정 과정을 제안한다. 시공단계 및 시공하중이 간편법에 의하여 정의되고, 각 시공단계별로 슬래브 모멘트 및 탄성 처짐, 유효단면2차모멘트가 계산된다. 주열대와 중간대에서의 탄성 처짐은 유효단면2차모멘트 효과에 의해 비탄성 처짐으로 증폭되며, 슬래브 중앙부 처짐은 교차보법에 의하여 산정된다. 제안된 방법은 기존 실험 결과 및 비선형 해석 결과와의 비교를 통하여 검증된다. 또한, 제안법의 적용을 통하여, 시공 중인 플랫 플레이트의 처짐에 대한 시공주기 및 동바리 지지 층 수의 영향이 분석된다.

확률.신뢰도 기법을 적용한 CFRP 플레이트 표면매립보강 콘크리트 철도교의 임계보강비 산정 (Critical Strengthening Ratio of CFRP Plate Using Probability and Reliability Analysis for Concrete Railroad Bridge Strengthened by NSM)

  • 오홍섭;선종완;오광진;심종성;주민관
    • 콘크리트학회논문집
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    • 제21권6호
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    • pp.681-688
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    • 2009
  • 철도교량은 일반적으로 공용기간동안 진동과 충격에 의한 구조적 영향을 받는다. 이와 같은 이유로 내하력 증진을 위한 보강성능 검토 시 철도교에 작용하는 외부하중에 효율적으로 저항할 수 있는 보강성능이 요구된다. 이 연구에서는 철도교의 공용 중 진동 및 충격하중에 효율적으로 저항할 수 있는 보강공법으로써 NSM 보강공법을 제안하였다. 이는 기존 탄소섬유외부부착 공법에 비해 부착성능 및 보강성능이 우수한 공법이다. NSM 보강공법은 현재 다양한 실험적 연구들이 진행되고 있으나, 실교량으로의 범용적인 적용을 위해서는 보강설계에 필요한 합리적인 보강비 산정이 필수적이다. 이를 위해, 이 연구에서는 재료적 및 기하학적 불확실성이 반영된 확률 신뢰도기반 NSM 보강비 산정방법을 제안하여 임계보강비를 산정하고자 한다. 이를 위해, Monte Carlo Simulation(MCS) 기법으로 도출된 재료 및 단면치수에 대한 불확실성 특성을 내부저항모멘트 설계식에 반영하여, 외부활하중의 불확실성 특성이 반영된 외부하중모멘트에 대한 안전도 평가를 수행하였으며, 목표신뢰성지수 3.5를 만족할 수 있도록 하는 CFRP 플레이트의 임계보강비를 산출하였다.

Investigating the Au-Cu thick layers Electrodeposition Rate with Pulsed Current by Optimization of the Operation Condition

  • Babaei, Hamid;Khosravi, Morteza;Sovizi, Mohamad Reza;Khorramie, Saeid Abedini
    • Journal of Electrochemical Science and Technology
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    • 제11권2호
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    • pp.172-179
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    • 2020
  • The impact of effective parameters on the electrodeposition rate optimization of Au-Cu alloy at high thicknesses on the silver substrate was investigated in the present study. After ensuring the formation of gold alloy deposits with the desired and standard percentage of gold with the cartage of 18K and other standard karats that should be observed in the manufacturing of the gold and jewelry artifacts, comparing the rate of gold-copper deposition by direct and pulsed current was done. The rate of deposition with pulse current was significantly higher than direct current. In this process, the duty cycle parameter was effectively optimized by the "one factor at a time" method to achieve maximum deposition rate. Particular parameters in this work were direct and pulse current densities, bath temperature, concentration of gold and cyanide ions in electrolyte, pH, agitation and wetting agent additive. Scanning electron microscopy (SEM) and surface chemical analysis system (EDS) were used to study the effect of deposition on the cross-sections of the formed layers. The results revealed that the Au-Cu alloy layer formed with concentrations of 6gr·L-1 Au, 55gr·L-1 Cu, 24 gr·L-1 KCN and 1 ml·L-1 Lauryl dimethyl amine oxide (LDAO) in the 0.6 mA·cm-2 average current density and 30% duty cycle, had 0.841 ㎛·min-1 Which was the highest deposition rate. The use of electrodeposition of pure and alloy gold thick layers as a production method can reduce the use of gold metal in the production of hallow gold artifacts, create sophisticated and unique models, and diversify production by maintaining standard karats, hardness, thickness and mechanical strength. This will not only make the process economical, it will also provide significant added value to the gold artifacts. By pulsating of currents and increasing the duty cycle means reducing the pulse off-time, and if the pulse off-time becomes too short, the electric double layer would not have sufficient growth time, and its thickness decreases. These results show the effect of pulsed current on increasing the electrodeposition rate of Au-Cu alloy confirming the previous studies on the effect of pulsed current on increasing the deposition rate of Au-Cu alloy.