• 청정기술
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• 제10권2호
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• pp.111-120
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• 2004

피혁 탈모 공정 폐수의 질소감소 및 황화물 감소, COD, BOD의 오염부하를 감소할수 있는 탈모공정 처리용 환경 친화적 피혁용 약품을 제조 하였다. 본 연구에서 개발한 Hair saving 공정처리제는 Urea, Mercaptan을 기본 물질로 하는 Liming agent와 Unhairing assist 제품을 제조하였다. Hair saving 공정에 처리한 결과 기존의 Hair burning 방법에 비해 회수된 모의 양이 약 2배 정도 증가하였다. 혁의 품질 및 생산성 평가의 지표인 수율을 좌우하는 Grain상태, 수축현상(Drawing)이 개선이 가능하였다. Wet Blue 및 완성원단에서의 인장, 인열 등의 물성과 Softness및 Touch 등의 가죽 본래의 천연감도 증대되는 효과가 있었다. 또한, 탈모공정후 배출 배수에서의 COD, T-N 농도가 약 50% 이상 감소 가능한 것을 확인 가능하였다.

• 한국토양비료학회지
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• 제49권5호
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• pp.548-554
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• 2016

Optimal range of soil physical quality to enhance crop productivity or to improve environmental health is still in dispute for the upland soil. We hypothesized that the optimal range might be established by comparing soil physical parameters and their interactions inhibiting crop growth. The parameter identifying optimal range covered favorable conditions of aeration, permeability and root extension. To establish soil physical standard two experiments were conducted as follows; 1) investigating interactions of bulk density and aeration porosity in the laboratory test and 2) determining effects of soil compaction and deep & conventional tillage on physical properties and crop growth in the field test. The crops were Perilla frutescens, Zea mays L., Solanum tuberosum L. and Secale cereael. The saturated hydraulic conductivity, bulk density from the root depth, root growth and stem length were obtained. Higher bulk density showed lower aeration porosity and hydraulic conductivity, and finer texture had lower threshold bulk density at 10% aeration bulk density. Reduced crop growth by subsoil compaction was higher in silt clay loam compared to other textures. Loam soil had better physical improvement in deep rotary tillage plot. Combined with results of the present studies, the soil physical quality was possibly assessed by bulk density index. Threshold subsoil bulk density as the upper value were $1.55Mg\;m^{-3}$ in sandy loam, $1.50Mg\;m^{-3}$ in loam and $1.45Mg\;m^{-3}$ in silty clay loam for optimal soil physical quality in upland.

• 경영과정보연구
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• 제32권1호
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• pp.135-151
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• 2013

본 연구는 국립대학교병원의 재정자립도 향상을 위한 생산성 관련 요인들을 파악하여 효율적인 자원운영에 관한 시사점을 도출하고자 12개 국립대학교병원의 2007년부터 2010년까지의 4개년 동안의 자료를 분석한 결과 총자본 투자효율, 유형고정자산 투자효율, 인건비 투자효율, 의료수익 부가가치율이 국립대학교병원들 간에 유의한 차이가 있었다. 그리고 국립대학병원의 투자효율과 수익성 간의 관계를 살펴본 결과, 기본환경요인 변수를 독립변수에 포함하지 않았을 경우와 포함한 경우에 수익성 지표인 의료수익 의료이익율의 영향요인이 다르게 나타남을 알 수 있었으며, 기본환경요인을 적용한 경우 국립대학교병원의 의료수익 의료이익율은 생산활동에 투자된 유형고정자산 투자효율이 높을수록, 인건비 투자효율이 높을수록, 의료수익 부가가치율이 낮을수록 수익성이 높은 것으로 확인되었다.

• 한국광학회지
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• 제18권3호
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• pp.216-220
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• 2007

본 논문에서는 굴절률 차이가 큰 폴리머 광 도파로를 이용하여 광대역 파장가변이 가능한 이중 링 공진기 Add/Drop 필터를 제작하였다. Add/Drop 필터의 제작시 공정 오차에 둔감한 특성을 갖도록 광 결합기를 설계하였다. 코어와 클래딩의 굴절률은 1550 nm 파장 대역에서 각각 1.51, 1.378로 약 $100{\mu}m$ 정도의 곡률 반경을 가지는 곡선 도파로를 수용할 수 있다. 두 개의 링이 동시에 공진하는 파장 대역에서 Drop 특성은 이웃하는 피크 좌다 약 2.9 dB 이상 높은 특성을 보였다. 이 필터는 반사형 반도체 광증폭기 등과의 하이브리드 집적을 통하여 광대역 파장 가변 레이저 다이오드를 구현하는데 활용할 수 있을 것으로 기대된다.

• 한국병원경영학회지
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• 제21권2호
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• pp.1-12
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• 2016

This study examines academic research trends and the change of patterns by analyzing researches related to hospital management registered in Korea Citation Index(KCI) from 2010 to 2014 and offers basic information for interests and future research demands in the field of hospital management As research subjects, a total of 694 published articles were selected. It's to analyze them by dividing into research topics, methods and author's characteristics, and to present them by classifying the period into 2010-2011, 2012-2013, 3rd quarter of 2014 since there was no significant difference in the result between adjacent years. As a result, Korean Journal of Hospital Management has accounted for the highest published rate year after year. In the research topic analysis, it showed a decreasing trend in these research topics as medical marketing and patient satisfaction which became the biggest issue in 2010-2011 significantly were lower in 2014, but an increasing trend in job satisfaction, job stress, labor administration and workforce productivity. The most frequently cited keywords were hospital employees, job satisfaction, organizational commitment, job stress, turnover intention. According to the research method analysis, the survey was the most popular method for data collection. However, Interview and medical records as data sources showed a decline trend. As analysis methods, multivariate analysis of quantitative methods was most used. Finally, as a result of analyzing main author's characteristics, the ratio of the authors belonging to health administration and nursing departments of the academic world increased gradually. In the regional distribution, organizations in Seoul are most common, those in Daegu Gyeongbuk areas, foreign organizations showed a tendency to decrease. This is the first study to examine the annual trend on hospital management-related research issues among articles published in domestic journal and we found qualitative and quantitative advances in hospital management research filed.

• Journal of Crop Science and Biotechnology
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• 제10권2호
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• pp.57-63
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• 2007

Due to the strong influence of nitrogen(N) on plant productivity, a vast amount of N fertilizers is used to maximize crop yield. Over-use of N fertilizers leads to severe pollution of the environment, especially the aquatic ecosystem, as well as reducing farmer's income. Growing of N-efficient cultivars is an important prerequisite for integrated nutrient management strategies in both low- and high-input agriculture. Taking maize as a sample crop, this paper reviews the response of plants to low N stress, the physiological processes which may control N-use efficiency in low-N input conditions, and the genetic and molecular biological aspects of N-use efficiency. Since the harvest index(HI) of modern cultivars is quite high, further improvement of these cultivars to adapt to low N soils should aim to increase their capacity to accumulate N at low N levels. To achieve this goal, establishment and maintenance of a large root system during the growth period may be essential. To reduce the cost of N and carbon for root growth, a strong response of lateral root growth to nitrate-rich patches may be desired. Furthermore, a large proportion of N accumulated in roots at early growth stages should be remobilized for grain growth in the late filling stage to increase N-utilization efficiency. Some QTLs and genes related to maize yield as well as root traits have been identified. However, their significance in improving maize NUE at low N inputs in the field need to be elucidated.

• Safety and Health at Work
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• 제5권4호
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• pp.203-209
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• 2014

Background: Coal mining is of significant economic importance to the Australian economy. Despite this fact, the related workforce is subjected to a number of psychosocial risks and musculoskeletal injury, and various psychological disorders are common among this population group. Because only limited research has been conducted in this population group, we sought to examine the relationship between physical (pain) and psychological (distress) factors, as well as the effects of various demographic, lifestyle, and fatigue indicators on this relationship. Methods: Coal miners (N = 231) participated in a survey of musculoskeletal pain and distress on-site during their work shifts. Participants also provided demographic information (job type, age, experience in the industry, and body mass index) and responded to questions about exercise and sleep quality (on-and off-shift) as well as physical and mental tiredness after work. Results: A total of 177 workers (80.5%) reported experiencing pain in at least one region of their body. The majority of the sample population (61.9%) was classified as having low-level distress, 28.4% had scores indicating mild to moderate distress, and 9.6% had scores indicating high levels of distress. Both number of pain regions and job type (being an operator) significantly predicted distress. Higher distress score was also associated with greater absenteeism in workers who reported lower back pain. In addition, perceived sleep quality during work periods partially mediated the relationship between pain and distress. Conclusion: The study findings support the existence of widespread musculoskeletal pain among the coal-mining workforce, and this pain is associated with increased psychological distress. Operators (truck drivers) and workers reporting poor sleep quality during work periods are most likely to report increased distress, which highlights the importance of supporting the mining workforce for sustained productivity.

• 한국토양비료학회지
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• 제50권6호
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• pp.509-519
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• 2017

Crop simulation models are valuable tools for estimating crop yield, environmental factors and management practices. The objective of this study was to evaluate the effect of soil types on barley productivity using CERES (Crop Environment REsource Synthesis)-barley, cropping system model. So the behavior of the model under various soil types and climatic conditions was evaluated. The results of the sensitivity analysis in temperature, $CO_2$, and precipitation showed that soil types had a direct impact on the simulated yield of CERES-barley model. We found that barley yield in clay soils would be more sensitive to precipitation and $CO_2$ in comparison with temperature. And the model showed limited accuracy in simulating water and nitrogen stress index for soil types. In general, the barley grown on clay soils were less sensitive to water stress than those grown on sandy soils. Especially it was found that the CERES model underestimated the effect of water stress in high precipitation which led to overprediction of crop yield in clay soils. In order to solve these problems and successfully forecast grain yield, further studies on the modification of the water stress response of crops should be considered prior to use of the CERES-barley model for yield forecasting.

• Safety and Health at Work
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• 제12권3호
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• pp.324-338
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• 2021

Background: We hypothesized that the growing demand of Korean workers for work-life balance would change the factors influencing job satisfaction. We sought to verify our hypothesis by conducting a conjoint analysis based on the Korean Working Conditions Survey (KWCS). Methods: We analyzed the raw data of the KWCS, conducted by the Occupational Safety and Health Research Institute from 2006 to 2017. To complete the analysis, we counted on a conjoint model of analysis, typically used in the analysis of customer satisfaction. The dependent variable was the satisfaction of workers with their working conditions, and the independent variables were the job quality indicators identified by Eurofound. Results: The factors that have the greatest impact on working conditions satisfaction are summarized as follows: "physical environment" for the first wave, "adverse social behavior" for the second wave, "occupational status" for the third and fourth waves, and "management quality" for the fifth wave. "Earnings" were not a major factor in determining employee job satisfaction, and the relative importance index is decreasing. Conclusion: According to the results of the analysis of the tendencies of Korean workers, the factors that affect the satisfaction with the working conditions have changed over time. It is crucial to identify factors that affect working conditions to assure the health and productivity of workers. The results of this study demonstrate that policymakers and employers are required to attentively consider human relations and social environment at work to improve working conditions in the future.

• The Korean Journal of Pain
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• 제34권1호
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• pp.82-93
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• 2021

Background: This study used bibliometric analysis of articles published about the topic of regional anesthesia from 1980-2019 with the aim of determining which countries, organizations, and authors were effective, engaged in international cooperation, and had the most cited articles and journals. Methods: All articles published from 1980-2019 included in the Web of Science database and found using the keywords regional anesthesia/anaesthesia, spinal anesthesia/anaesthesia, epidural anesthesia/anaesthesia, neuraxial anesthesia/anaesthesia, combined spinal-epidural, and peripheral nerve block in the title section had bibliometric analysis performed. Correlations between the number of publications from a country with gross domestic product (GDP), gross domestic product (at purchasing power parity) per capita (GDP PPP), and human development index (HDI) values were investigated with the Spearman correlation coefficient. The number of articles that will be published in the future was estimated with linear regression analysis. Results: Literature screening found 11,156 publications. Of these publications, 6,452 were articles. The top 4 countries producing articles were United States of America (n = 1,583), Germany (585), United Kingdom (510), and Turkey (386). There was a significant positive correlation found between the GDP, GDP PPP, and HDI markers for global countries with publication productivity (r = 0.644, P < 0.001; r = 0.623, P < 0.001, r = 0.542, P < 0.001). The most productive organizations were Harvard University and the University of Toronto. Conclusions: This comprehensive study presenting a holistic summary and evaluation of 6,452 articles about this topic may direct anesthesiologists, doctors, academics, and students interested in this topic.