• 한국보육지원학회지
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• 제17권6호
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• pp.93-108
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• 2021

Objective: This study examined the mediating effect of adolescents' self-esteem on the relationship between their childhood abuse experiences and school rule-breaking behavior. Methods: The research participants consisted of 1,748 adolescents aged from 15 to 16. Adolescents' school rule-breaking behavior and self-esteem were measured in 2016, whereas their childhood abuse experiences were measured in 2010. Panel data collected by the National Youth Policy Institute were analyzed using the bootstrapping technique and PROCESS Macro for SPSS. Results: The results of the study are as follows. First, the adolescents' childhood abuse experiences affected their school rule-breaking behavior. That is, the adolescents who were abused by their parents were at higher risk of breaking school rules later in life. Second, the adolescents' self-esteem mediated the relationship between their childhood abuse experiences and school rule-breaking behavior. The adolescents who were abused by their parents tend to have low levels of self-esteem and thereby break school rules. Conclusion/Implications: The present study shows the possibility that childhood abuse experiences lead to adolescents' problematic behaviors, such as school rule violation. It also indicates that it is necessary to provide counseling and therapeutic interventions for enhancing the self-esteem of adolescents of the at-risk group with childhood abuse experiences.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.329-334
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• 2001

In this paper, the crack properties of steel fiber reinforced concrete (SFRC) structures for environment by experimental and analytical methods are discussed. The major role played by the steel fiber occurs in the post-cracking zone, in which the fibers bridge across the cracked matrix. Because of its improved ability to break crack, SFRC has better crack properties than that of reinforced concrete (RC). Crack properties are influenced by longitudinal reinforcement ratio, volume and type of steel fiber, strength of concrete.

• Korea-Australia Rheology Journal
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• 제20권3호
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• pp.109-116
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• 2008

The effect of intermolecular aggregation induced by hydrophobic and electrostatic interactions on shear and elongational flow properties of aqueous acrylic thickener solutions is discussed. Complex shear modulus is determined at frequencies up to $10^4$ rad/s employing oscillatory squeeze flow. Extensional flow behavior is characterized using Capillary Break-up Extensional Rheometry. Aqueous solutions of poly(acrylic acid)(PAA)/poly(vinylpyrrolidone-co-vinylimidazole) (PVP-VI) mixtures exhibit unusual rheological properties described here for the first time. Zero-shear viscosity of the mixtures increases with decreasing pH and can exceed that of the pure polymers in solution by more than two orders of magnitude. This is attributed to the formation of complexes induced by electrostatic interactions in the pH range, where both polymers are oppositely charged. PAA/PVP-VI mixtures are compared to the commercial thickener Sterocoll FD (BASF SE), which is a statistical co-polymer including (meth) acrylic acid and ethylacrylate (EA) forming aggregates in solution due to "sticky" contacts among hydrophobic EA-sequences. PAA/PVP-VI complexes are less compact and more deformable than the hydrophobic Sterocoll FD aggregates. Solutions of PAA/PVP-VI exhibit a higher zero-shear viscosity even at lower molecular weight of the aggregates, but are strongly shear-thinning in contrast to the weakly shear-thinning solutions of Sterocoll FD. The higher ratio of characteristic relaxation times in shear and elongation determined for PAA/PVP-VI compared to Sterocoll FD solutions reflects, that the charge-induced complexes provide a much stronger resistance to extensional flow than the aggregates formed by hydrophobic interactions. This is most likely due to a break-up of the latter in extensional flow, while there is no evidence for a break-up of complexes for PAA/PVP-VI mixtures. These flexible aggregates are more suitable for the stabilization of thin filaments in extensional flows.

• 대한기계학회논문집A
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• 제25권7호
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• pp.1031-1038
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• 2001

In order to verify the analytical methods predicting failure behavior of cracked piping, full-scale pipe tests are crucial in nuclear power plant piping. For this reason, series of international test programs have been conducted. However, full-scale pipe tests require expensive testing equipment and long period of testing time. The objective of this paper is to develop a test system which can economically simulate the full-scale pipe test regarding the integrity evaluation. This system provides the failure behavior of cracked pipe by testing a wide-plate specimen. The system provides the failure behavior of cracked pipe by testing a wide-plate specimen. The system was developed for the integrity evaluation of nuclear piping based on the methodology of hardware-in-the-loop (HiL) simulation. Using this simulator, the piping integrity can be evaluated based on the elastic-plastic behavior of full-scale pipe, and the high cost full-scale pipe test may be replaced with this economical system.

• 한국가스학회지
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• 제3권1호
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• pp.1-7
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• 1999

알루미늄합금(5083-0)의 표면균열시험편의 관통전후의 피로거동을 조사하였다. 관통전의 피로균열형상은 거의 반타원형이며, 측정된 형상비는 Newman-Raju식의 K를 이용하여 계산한 값보다 더 크다. 관통후의 뒷면에서의 피로균열성장거동은 거의 유사하였으며 3영역으로 나누어졌다. 표면균열길이가 긴 경우, 피로균열전파법칙을 사용함으로서 표면균열재의 판두께 관통후의 피로균열 전파특성을 정량적으로 평가될 수 있음을 알 수 있었다.

• 대한기계학회논문집A
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• 제25권6호
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• pp.930-937
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• 2001

The friction and wear behavior of short carbon fiber reinforced polyetheretherketone was studied experimentally under dry sliding conditions against SCM440(AISI 4140) disks with different surface roughness and hardness at the low sliding speeds and the high pressures on a pin-on-disk apparatus. Under the low disk surface roughness value the earsplitting noise and stick-slip were occurred. The increased adhesion friction and wear factor with stick-slip made the friction and wear behavior worse. Under the high disk surface hardness the break and falling-off of carbon fibers were accelerated. The carbon fibers fallen off from the matrix were ground into powder between two wear surfaces and this phenomenon caused abrasive friction and wear factor to increase. So the friction and wear behavior became worse. With the transfer film made of wear particles formed on a disk, the carbon powder film formed on a pin lowered a friction coefficient.

• 한국전자통신학회논문지
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• 제17권4호
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• pp.723-728
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• 2022

본 연구는 운전자의 위험운전행동을 평가하고 정량화한 방법에 관한 것이다. 정량화 방법은 차량의 운행을 시작 이후 휴식 없이 연속적으로 주행한 시간, 과속, 급가속, 과속주행 시간 등 다양한 주행정보를 실시간으로 산출하도록 한다. 이러한 정량화된 위험운전행동 값은 개별로 안전운전지수로 제공하거나, 도로를 운행하는 운전자에 대하여 집단에 대한 평가 혹은 차량군에 대한 평가 등으로 객관화하는데 사용할 수 있다.

• 한국식품저장유통학회지
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• 제31권2호
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• pp.199-209
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• 2024

This study explored how temperature, time, and moisture content affect the rheological properties (apparent viscosity, flow behavior index, and consistency coefficient) of stored tomato and pepper purees. These purees were prepared with moisture contents of 85%, 90%, and 95% (w/v) using the hot-break method and tested over 6 days at 2-day intervals and temperatures of 5℃, 10℃, and 15℃. Results displayed distinct ranges for apparent viscosity, consistency coefficient, and flow behavior indices: tomato puree (2,519.9-4,324.6 mPa·s, 258.0-550.6 mPa·Sn, 1.80-0.48) and pepper puree (2,105.6-4,562.0 mPa·s, 268.4-580.4 mPa·Sn, 0.22-0.48). The temperature and storage time had significant (p≤0.05) effects, but moisture content did not affect these properties. Flow behavior and consistency coefficients demonstrated relative variation with apparent viscosity, indicating pseudoplastic behavior. Optimal processing and storage conditions were identified within specific ranges: 13.21-14.42℃ for 2 days with 92.22-94.23% (w/v) moisture content for pepper, and 8.42-11.77℃ for 2-6 days with 85% (w/v) moisture for tomato.

• 노동경제논집
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• 제35권1호
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• pp.89-109
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• 2012

본 연구는 실업률 변화와 성장률 간의 경험적 관계를 나타내는 오쿤의 법칙을 우리나라의 자료를 이용하여 추정하고 그 결과를 새롭게 해석하는 것을 목표로 하고 있다. 분석 결과는 다음과 같다. 첫째, 벤치마크 오쿤의 추정계수 ${\beta}$는 방법론에 따라 대략 2~4의 계수 값을 보여주어 선진국의 경우보다 다소 높은 값을 보여주었다. 둘째, 경기변동에 따른 비대칭적인 반응이 관측되기는 하지만 추정방법에 따라 혼재된 결과를 보여주고 있다. 마지막으로 1979~80년, 1997~98년 등의 구조변화를 반영한 오쿤의 추정계수는 벤치마크와 비슷한 값으로 추정되었다.

• 한국식품과학회지
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• 제20권6호
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• pp.834-839
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• 1988

쌀전분에 미치는 쌀지질의 영향을 살펴보기 위하여 극성용매인 85% 메탄올로 탈지처리한 전분 시료 및 탈지 후 1% palmitic acid를 첨가한 시료를 제조하여 이화학적 성질을 생전분과 비교 검토하였다. 탈지에 의해 아밀로오스 함량이 다소 높게 나타났으며, 광투과도, 팽화력 및 용해도는 생전분과 지방산 첨가전분은 2단거동을 나타내었으나 탈지에 의해 소실되었다. X-선 회절양상은 전형적인 A형을 나타내었으나, 탈지처리에 의해 상대결정도는 감소하였으며, 지방산 첨가로 상대결정도는 증가하였다. 아밀로그라프에 의한 호화양상은 탈지에 의해 최고점도와 break down이 소실되었으며 set back은 증가하는 경향을 보였고 지방산 첨가로 다시 생전분과 비슷한 특성을 나타내었다.