• Geomechanics and Engineering
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• 제15권6호
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• pp.1153-1160
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• 2018

Rockbursts, catastrophic events involving the violent release of elastic energy stored in rock features, remain a worldwide challenge for geoengineering. Especially at deep-mining sites, rockbursts can occur in hard, high-stress, brittle rock zones, and the associated risk depends on such factors as mining activity and the stress on surrounding rocks. Rockbursts are often sudden and destructive, but there is still no unified standard for predicting them. Based on previous studies, a new Bayesian multi-index model was introduced to predict and evaluate rockbursts. In this method, the rock strength index, energy release index, and surrounding rock stress are the basic factors. Values from 18 rock samples were obtained, and the potential rockburst risks were evaluated. The rockburst tendencies of the samples were modelled using three existing methods. The results were compared with those obtained by the new Bayesian model, which was observed to predict rockbursts more effectively than the current methods.

• 한국표면공학회지
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• 제53권5호
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• pp.219-226
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• 2020

This paper investigated the characteristics of anodized aluminum 6061-T6 alloy for corrosion and stress corrosion cracking(SCC) under natural seawater. The hard anodizing oxide film formed on the 6061-T6 was a uniform thickness of about 25 ㎛. The corrosion characteristics were performed with a potentiodynamic polarization test. SCC was characterized by a slow strain rate tensile test under 0.005mm/min rate. As a result, the anodizing film showed no significant effect on SCC in the slow strain rate test. However, the corrosion current density of base metal was measured to be approximately 13 times higher than that of the anodized specimen. Therefore, the anodizing film significantly improved the corrosion resistance of 6061-T6 alloy in natural seawater.

• Food Science and Biotechnology
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• 제16권6호
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• pp.967-974
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• 2007

The present work is aimed to evaluate the protective effect of glutathione-enriched Saccharomyces cerevisiae FF-8 strain on carbon tetrachloride ($CCl_4$)-induced hepatotoxicity and oxidative stress in rats. The activities of liver markers (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, lactate dehydrogenase), lipid peroxidative index (thiobarbituric acid-reactive substances), and the antioxidant status (reduced glutathione) were used to monitor those protective roles of FF-8 strain. The liver marker enzymes in plasma and the lipid peroxidation in the liver were increased when $CCl_4$ was treated but these were significantly decreased by FF-8 strain treatment. The hepatic concentration of glutathione in the current glutathione-enriched FF-8 strain fed animal was approximately twice as high as the normal, but this was slightly increased in response to $CCl_4$ plus glutathione-enriched FF-8 strain. The increased liver triglyceride concentration due to the $CCl_4$ treatment was significantly decreased by FF-8 strain and the reduced level reached to that of normal group. Administration of FF-8 strain in normal rat did not show any signs of harmful effects. Therefore, the current findings suggest that FF-8 strain could be an effective antioxidant with no or negligible side-effects and it might be useful for the purpose of protection treatment of hepatotoxicity and oxidative stress in $CCl_4$-treatment in rat.

• 융합정보논문지
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• 제7권1호
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• pp.81-86
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• 2017

오늘날, 대학생들은 취업준비를 하면서 많은 어려움을 겪고 있다. 따라서 본 연구는 대학생들의 산업체 진출을 위한 구직준비역량과 이에 대한 대학생활 스트레스에 미치는 영향을 알아보고자 하였다. 이를 위하여 연구대상으로는 충남에 위치한 N대학교의 교양수업을 듣는 학생 158 명으로 표집하였다. 또한 분석방법으로는 연구의 목적을 위하여 대학생활 스트레스에 대한 탐색적 요인분석과 일원배치분산분석 및 상관분석을 실시하였다. 그 결과 학년에 따라서는 대학생활 스트레스와 구직준비역량은 일원배치 분석결과 통계적으로 유의미한 영향이 나타났으며, 대학생활 스트레스와 구직준비역량간의 상관관계분석 결과는 관계가 없는 것으로 나타났다. 본 연구를 통해 구직역량을 위하여 대학은 어떠한 대책을 마련해야 하는지에 대한 지속적 고민과 함께 구체적이고 체계적인 대안이 필요할 것이라고 사료된다. 또한 대학생들의 산업체에 진출할 구직역량에 대한 인식의 확대와 준비의 중요성에 대하여 시사점을 제공하고자 한다.

• The Korean Journal of Physiology and Pharmacology
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• 제2권6호
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• pp.677-685
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• 1998

To investigate the effects of neonatal stress on behavior and neurochemistry, rats were exposed to the footshock stress on postnatal day (PND) 14 or PNDs 14 and 21. Rats were exposed to uncontrollable electric shocks delivered to the floor with a constant current (0.8 mA) for 5 sec period. Daily sessions consisted of 60 trials on a random time schedule with an average of 55 sec. The first exposure to footshocks on PND 14 decreased body weight gain for 1 day. However, the second exposure to footshocks on PND 21 did not affect body weight gain. Exploratory activity was measured by exposing a rat to a novel environment 24 h after experience of footshocks. Similar to the body weight changes, a decreased activity was noted after the first exposure to footshocks, while no changed activity was noted after the second exposure to footshocks. However, the Bmax value of $5-HT_{2A/2C}$ receptors in the cortex decreased by the second exposure to footshocks, but not by the first exposure to footshocks. Moreover, an autoradiographic study revealed that the density of $[^3H]dexamethasone$ binding in hippocampus decreased in rats exposed to footshocks 4 times during PND $14{\sim}20.$ These results suggest that the uncontrollable footshock stress changes 5-hydroxytryptamine and glucocorticoid receptor systems acutely and that the repeated exposure to the same stress may not elicit behavioral alterations by the compensatory activity of young brain although changes in some neurochemistry exist.

• 임상간호연구
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• 제24권2호
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• pp.255-262
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• 2018

Purpose: This study aimed to identify the view of life and death among ICU nurses and to analyze the problems related to end-of-life care in the current ICUs. Methods: A descriptive study design was used. The participants were 975 nurses working in the intensive care units of 16 general hospitals. Using a descriptive survey design, data were collected from August to December in 2016 and were analyzed using descriptive statistics, t-test, ANOVA, correlation analysis, and multiple regression analysis. Results: As a result of a correlation analysis of the data, Death perception had a significant positive correlation with EOL of nursing attitudes(r=.100, p=.002), and negative correlation with EOL stress care(r=-.221, p=<.001). The regression model explained for individual characteristics in the model, age(${\beta}=.126$, p<.001) and death perception(${\beta}=.182$, p<.001), Satisfaction of the EOL care(${\beta}=.173$, p<.001), Healing training needs on the EOL(${\beta}=-.144$, p<.001) were the most influential factors for EOL stress. Conclusion: Results reveal that ICU nurses have a moderate level of EOL stress, and that individual, age, death perception, Satisfaction of the EOL care, Healing traning needs on the EOL relevant in ICU nurses' EOL stress. Programs or interventions to reduce EOL stress and to should be developed taking into account these multidimensional factors.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.243-246
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• 1999

We studied the MOSFET characteristics and the hot-carrier reliability with the sidewall spacer composition and the post gate oxidation thickness in 0.20${\mu}{\textrm}{m}$ gate length transistor. The MOSFET with NO(Nitride＋Oxide) sidewall spacer exhibits the large degradation of hot-carrier lifetime because there is no buffering oxide against nitride stress. When the post gate oxidation is skipped, the hot-carrier lifetime is improved, but GIDL (Gate Induced Drain Leakage) current is also increased.

• Journal of Animal Science and Technology
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• 제64권1호
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• pp.84-96
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• 2022

The current study was conducted to evaluate the effect of calcium-enriched fatty acid supplementation on the growth performance, blood metabolites, intestinal morphology, carcass traits, and nutrient digestibility of broilers subjected to chronic heat stress. A total of 210 one-day-old broiler chicks (40.12 ± 0.25 g) were randomly allocated to one of five dietary treatments, to obtain six replicates per treatment. Broilers were subjected to chronic heat stress from day 21 to day 35, post-hatching, at 34℃ for 9 h per day. The body weight (BW) and feed intake of the experimental broilers were recorded weekly, and the average daily gain (ADG) and feed conversion ratio (FCR) were calculated accordingly. Rectal temperature was measured to compare the basal body temperatures between individuals, and blood samples were collected on days 21 and 35 to evaluate basal body temperature, serum total cholesterol, and the triglyceride content of the broilers. On days 21 and 35, one broiler from each cage (n=6) was euthanized to measure carcass trait parameters, nutrient digestibility in digesta, and intestinal morphology. On days 14, 28, and 35, the broilers fed 2.0% calcium-enriched fatty acids had higher BW (p < 0.05) than those fed the other diets. However, no differences (p > 0.05) were found in the average daily feed intake (ADFI) between dietary treatments over the 35 experimental days. On the other hand, on day 21, post-hatching, the broilers fed the 2.0% calcium-enriched fatty acid diet had improved (p < 0.05) dietary feed efficiencies compared to the other treatments. On day 28, the broilers fed the 5.0% of calcium-enriched fatty acid diet also had higher (p < 0.05) dietary feed efficiencies than those fed with the other dietary treatments. No effects (p > 0.05) on carcass weight, nutrient digestibility, intestinal morphology, or blood parameters were found between broilers fed with dietary treatments. This study demonstrated that the inclusion of an additive, containing 2.0% calcium-enriched fatty acid, to broiler diet could ameliorate the negative growth performance of broilers; and no interaction (p > 0.05) was observed between the calcium-enriched fatty acid and nutrient digestibility, digestive anatomy, blood metabolism, and carcass traits of broilers subjected to chronic heat stress conditions for 35 days post-hatching.

• 한국가금학회지
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• 제43권1호
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• pp.21-29
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• 2016

A total of 144 one-day-old male broilers (ROSS ${\times}$ Ross 308) ($42{\pm}0.1g$) were used in a completely randomized design and allotted to one of three dietary treatments to give 6 replicates per treatment (8 birds per cage). The three watery dietary treatments were 1) a corn-soybean meal-based relation [Negative control (NC); no antimicrobial compounds added] with tab water, 2) 8 ppm liquid-alpha-lipoic acid [Positive control (PC)] or 3) 100 ppm liquid-resveratrol. All dietary treatments were continuously provided as a liquid form. Birds were housed in a battery cage (n=48), and were offered liquid dietary treatments at all times. The ambient temperature was maintained at $32{\pm}1^{\circ}C$ for the first 3 weeks and decreased gradually to $28{\pm}1^{\circ}C$ by the end of the experiment (d 35) to induce moderate heat stress. One bird per pen (n=6) was euthanized via cervical dislocation at day 21 to obtain terminal ileum to measure villous height and crypt depth, while another bird per pen (n=6) was similarly euthanized at day 35 and used to harvest breast meat and drumsticks to evaluate meat quality traits. Birds fed liquid-resveratrol did not improve (P>0.05) body weight and average daily gain compared with those fed other dietary treatments from day 1 to day 35. Birds fed liquid-resveratrol had no effect (P>0.05) on villous height compared with birds were in other dietary treatments at day 21. Liquid-resveratrol had no effect (P>0.05) on thiobarbituric acid reactive substance (TBARS) in drumsticks compared with other dietary treatments at day 35. Furthermore, birds fed liquid-resveratrol had no effect (P>0.05) on DPPH radical scavenging activity both in breast meat and drumsticks compared with those fed other dietary treatments at day 35. Morphological changes of ileum were not observed by immunofluorescence, and the level of occludin protein from ileum extracts also did not differ among groups. Our results suggested that liquid form of antioxidant compounds used in the current study such as alpha-lipoic acid (8 ppm) or resveratrol (100 ppm) did not improve growth performance, meat quality traits and histology of terminal ileum compared with those fed negative control in broiler chickens under moderate heat stress for 35 days.

• 한국심리학회지:법
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• 제11권3호
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• pp.241-265
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• 2020

본 연구는 2019년 하반기를 기준으로 개정되어 현재 사용하고 있는 개정 후 범죄피해자 권리 안내문이 개정 전과 비교하여 일반인들의 범죄피해자 권리 이해도를 향상시키는지 파악하는 것을 목적으로 진행되었다. 더불어 학력 수준과 지각된 스트레스가 범죄피해자 권리 안내문과 함께 범죄피해자 권리 이해도에 미치는 영향을 탐색하였다. 이를 위해 성인 남녀 289명을 대상으로 연구자료를 수집 및 분석하였다. 연구 결과, 전반적으로 개정 전과 비교하여 개정 후 범죄피해자 권리 안내문을 읽은 조건에서 객관적 범죄피해자 권리 이해도가 높은 것으로 나타났으나, 주관적 범죄피해자 권리 이해도는 차이를 보이지 않았다. 개정 전·후 범죄피해자 권리 안내문과 학력 수준의 상호작용 효과는 객관적 범죄피해자 권리 이해도에 영향을 미치지 않는 것으로 나타났다. 개정 전·후 범죄피해자 권리 안내문이 주관적 범죄피해자 권리 이해도에 미치는 영향은 지각된 스트레스에 의해 부적으로 조절되는 경향성이 나타났다. 마지막으로 본 연구의 의의와 정책적 제언을 논의하였으며, 본 연구의 한계점과 더불어 후속 연구를 제언하였다.