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The Effect of Triple Injection on Engine Performance and Emissions in a HSDI Diesel Engine (3중분사가 HSDI 디젤엔진의 성능과 배기에 미치는 영향)

  • Choi, Wook;Park, Cheol-Woong;Kook, Sang-Hoon;Bae, Choong-Sik
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.5
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    • pp.40-57
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    • 2004
  • The effects of triple (pilot, main and after) injection on combustion and emission characteristics in a HSDI (High-Speed Direct Injection) diesel engine were investigated using a single-cylinder optical diesel engine equipped with a common-rail injection system. The pilot injection affected the spray and combustion evolution of the following main injection. It was found that the pilot injection reduced the ignition delay, which led to lowered NOx (Nitric Oxides) level, and increased IMEP (Indicated Mean Effective Pressure) due to slow combustion pace during an expansion stroke. The after-injection was shown to be effective in reducing PM (Particulate Matter) even when a small amount of fuel was added. The results suggest that a proper combination of individual injection strategy could bring about a good synergetic effect on engine performance and emission.

Relationship between Green Consumer Behavior, Environmental Knowledge, and Environmental Attitudes among Students at the University of Education (교육대학교 재학생의 녹색소비자행동과 환경지식 및 환경태도의 관계)

  • Keum, Jiheon
    • Journal of the Korean Home Economics Association
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    • v.51 no.1
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    • pp.89-95
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    • 2013
  • The purpose of this study is to identify a causal relationship among green consumer behavior, environmental knowledge and environmental attitudes of students at the university of education. A total of 366 copies of questionnaires were used for the data analysis; 31 copies were excluded due to lack of response to any given question. To ensure the reliability and validity of the questions, technical statistics were performed, such as frequency, ratio, average, standard deviation, skewness, and kurtosis via SPSS 15.0, item-total correlation and the totality, and reliability analysis. A structural analysis was undertaken via AMOS 7.0 in a bootstrapping method in order to perform a path analysis among variables as well as to assess the suitability of the model. The findings of the study were led to the following conclusions: First, the causal model among green consumer behavior, environmental knowledge and environmental attitudes of students at the university of education is suitable to the empirical analysis on research variables. Second, the environmental attitudes of students at the university of education has a direct, positive effect on green consumer behavior. Third, the environmental knowledge of students at the university of education has an indirect, positive effect on green consumer behavior.

Multi-scalar Dynamics of Cluster Development: The Role of Policies in Three Korean Clusters (다규모 공간에서 클러스터 발전의 역동성 -한국의 클러스터 사례에서 국가정책의 역할을 중심으로-)

  • Kim, Hyung-Joo;Lee, Jeong-Hyop
    • Journal of the Korean Geographical Society
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    • v.44 no.5
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    • pp.634-646
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    • 2009
  • This paper critically examines cluster dynamics and development in a multi-scalar approach, criticizing both the argument overemphasizing local networks and endogenous development for regional development and the contention highlighting global networks and the role of global players. We argue that state policies, exogenous and direct, play a significant part in cluster dynamics and development especially in the case of Korea where the state government's strong policies have led to rapid industrialization. We analyze multi-scalar factors, especially the government policies at a national level, in the development paths of the three cases including Ulsan automobile cluster, Daedeok research cluster, and Dongdaemun fashion cluster.

The study on the electrical and optical characteristics of a new structure for color ac plasma displays (새로운 전극구조를 가진 ac-PDP의 전기 광학적 특성에 관한 연구 (I))

  • Lee, Woo-Geun;Shin, Joong-Hong;Kim, Joon-Ho;Kim, Doo-Han;Cho, Jung-Soo;Park, Chung-Hoo
    • Proceedings of the KIEE Conference
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    • 1999.07e
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    • pp.2227-2229
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    • 1999
  • As a direct-view flat panel displays, there are many devices, such as plasma display panels(PDPs), vacuum fluorescent displays (VFDs), and light emitting diode(LED). Among these, a PDP is the first type of panel display to be made commercially available. A 'Plasma display' is the general term for a flat display utilizing the light emission that is produced by gas discharge. However, the brightness and Luminous efficiency are still not adequate for consumer television. So, the new sustain electrode type of ac PDP was proposed. By arranging the transparent electrode of quadrangle by zigzag, the area of electrode are reduced, and the length of electrode gap is increased. It generates a high luminous efficiency(corresponding to a 40% improvement of standard type), the same discharge voltage characteristics, and the low power consumption at same luminance.

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What is the Optimal Contraction Intensity and Duration in the Performance of Relaxation Techniques for Maximal Increase of Range of Motion? (관절가동범위 증진을 위한 이완 기법의 적절한 수축강도와 수축시간은?)

  • Shin, Seung-Sub
    • PNF and Movement
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    • v.14 no.1
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    • pp.59-65
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    • 2016
  • Purpose: The purpose of this study was to review articles in order to establish optimal contraction intensity and duration in the performance of relaxation techniques for maximal increase in range of motion. Methods: The Cochrane, EBSCO, Embase, Medline, ProQuest, PubMed, ScienceDirect, and Scopus databases were used to search articles from 1990 to January 2016. The search terms were "contract relax," "hold relax," "muscle energy technique (MET)," and "proprioceptive neuromuscular facilitation (PNF) stretching." Only experimental human studies (randomized controlled trials) that compared the effects of varying intensity and duration of isometric contraction were included. Non-English language and unpublished studies were excluded. Results: A total of 2,156 articles were initially identified, with only five eventually meeting the inclusion and exclusion criteria. Three studies compared the effects of varying intensity in isometric contraction and two studies compared the effects of varying duration in isometric contraction with regard to range of motion (ROM). Two articles suggested that submaximal voluntary isometric contraction was more effective than maximum voluntary isometric contraction (MVIC) in the improvement of ROM. One article showed that a longer contraction time led to greater increases in ROM. Conclusion: Submaximal voluntary isometric contraction was recommended during contract-relax exercises in healthy people. Lack of evidence makes it difficult to suggest the optimal duration of isometric contraction during relaxation techniques. For future research, high-quality evidence will be needed to establish the optimal contraction intensity for maximum improvement of ROM.

Formation of Polybrominated Dibenzo-p-dioxins/Furans (PBDDs/Fs) by the Pyrolysis of 2,4-Dibromophenol, 2,6-Dibromophenol, and 2,4,6-Tribromophenol

  • Na, Yun-Cheol;Hong, Jong-Ki;Kim, Kang-Jin
    • Bulletin of the Korean Chemical Society
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    • v.28 no.4
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    • pp.547-552
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    • 2007
  • This study examined the thermal reactions of 2,4-dibromophenol (diBP), 2,6-diBP and 2,4,6-triBP. The products obtained under pyrolytic conditions were analyzed by gas chromatography/mass spectrometry (GC/MS). 2,7-dibromodibenzo-p-dioxin (diBDD) was the major compound produced from the thermal reaction of 2,4-diBP. In addition, monoBDD and triBDDs were obtained through a process of debromination and bromination, respectively. The pyrolysis of 2,6-diBP and 2,4,6-triBP produced two major brominated dioxin isomers through direct condensation and a Smiles rearrangement. The two ortho-Brs in 2,6-diBP and 2,4,6-triBP mainly led to the production of dioxins, whereas in addition to 2,7-diBDD, 2,4-diBP produced two furans as minor products, 2,8-dibromodibenzofuran (diBDF) and 2,4,8-triBDF, through the intermediate dihydroxybiphenyl (DOHB). The maximum yield of the major dioxins was obtained at 400 oC, and decomposition by debromination at 500 oC resulted in less substituted bromodioxins.

The Mediating Effect of Empathy on the Relationship between Cultural Intelligence and Intercultural Adaptation in Intercultural Service Encounters

  • KONG, Lan Lan;MA, Zhi Qiang;JI, Sung Ho;LI, Jin
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.2
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    • pp.169-180
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    • 2020
  • Globalization has led to a dramatic increase in intercultural service encounters between services providers and customers from diverse cultural backgrounds. This paper explores the causal relationship between service employees‟ cultural intelligence and adaptive sales behavior in intercultural service encounters, and the mediating effect of cognitive and emotional empathy on this relationship. A quantitative survey methodology was utilized to collect data on 341 salespeople at duty-free shops located on Jeju Island, Korea. Data analysis was conducted using SPSS 18 and Amos 18. The results show that cultural intelligence has a significant impact on cognitive empathy, emotional empathy, and adaptive sales behavior. Cognitive empathy has a positive impact on adaptive sales behavior, whereas the relationship between emotional empathy and adaptive sales behavior is not significant. Additionally, cognitive empathy mediates the relationship of cultural intelligence and adaptive sales behavior. This study has useful managerial implications for employee selection, training, and development in service firms engaged in intercultural service encounters. This study extends prior research on intercultural service encounters by exploring the direct impact of cultural intelligence on intercultural adaptation and the mediating effect of empathy, suggesting the presence of a cognitive mechanism that plays a key role in the impact of cultural intelligence on adaptive sales behavior.

Characteristics of the Food Waste and Wastewater Discharged from Food Waste Treatment Process (음식물류폐기물 및 배출폐수의 특성)

  • Kim, Young-Kwon;Kim, Se-Mi;Kim, Min-Kyu;Choi, Jin-Taek;Nam, Se-Yong
    • Journal of Environmental Health Sciences
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    • v.35 no.6
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    • pp.526-531
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    • 2009
  • Waste generation was generally expected to steadily rise due to a rapid increase in population and economic growth. However, regulations on disposable goods and a volume-based waste fee system have led to a gradual reduction in the amount of waste. In the case of food waste, separation of food waste from other waste has been put in place since direct landfilling was banned in January 2005. The predicted generation amounts of food waste and wastewater in the model city were 54 ton/d and 127.3 ton/d by year 2020, respectively. However, appropriate treatment technologies for food waste and wastewater discharged from food waste treatment processes are yet to be established. In this study, the food waste and wastewater discharged from food waste treatment process in the model city were characterized by literal and field investigation.

Evaluation of Hydraulic Conductivity Function in Unsaturated Soils using an Inverse Analysis (역해석기법을 이용한 불포화토 투수계수함수 산정에 관한 연구)

  • Lee, Joonyong;Han, Jin-Tae
    • Journal of The Korean Society of Agricultural Engineers
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    • v.55 no.4
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    • pp.1-11
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    • 2013
  • Unsaturated hydraulic conductivity function is one of key parameters to solve the flow phenomena in problems of landslide. Prediction models for hydraulic conductivity function related to soil-water retention curve equations in many geotechnical applications have been still used instead of direct measurement of the hydraulic conductivity function since prediction models from soil-water retention curve equations are attractive for their fast and easy use and low cost. However, many researchers found that prediction models for the hydraulic conductivity function can not predict the hydraulic conductivity exactly in comparison with experimental outputs. This research introduced an inverse analysis to evaluate the hydraulic conductivity function corresponding to experimental output from the flow pump system. Optimisation process was carried out to obtain the hydraulic conductivity function. This research showed that the inverse analysis with flow pump system was suitable to assess the hydraulic conductivity in unsaturated soil, and the prediction models for the hydraulic conductivity were led to the significant discrepancy from actual experimental outputs.

PLUTONIUM MANAGEMENT OPTIONS: LIABILITY OR RESOURCE

  • Bairiot, Hubert
    • Nuclear Engineering and Technology
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    • v.40 no.1
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    • pp.9-20
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    • 2008
  • Since plutonium accounts for 40-50% of the power produced by uranium fuels, spent fuel contains only residual plutonium. Management of this plutonium is one of the aspects influencing the choice of a fuel cycle back-end option: reprocessing, direct disposal or wait-and-see. Different grades and qualities of plutonium exist depending from their specific generation conditions; all are valuable fissile material. Safeguard authorities watch the inventories of civil plutonium, but access to those data is restricted. Independent evaluations have led to an estimated current inventory of 220t plutonium in total (spent fuel, separated civil plutonium and military plutonium). If used as MOX fuel, it would be sufficient to feed all the PWRs and BWRs worldwide during 7 years or to deploy a FBR park corresponding to 150% of today' s installed nuclear capacity worldwide, which could then be exploited for centuries with the current stockpile of depleted and spent uranium. The energy potential of plutonium deteriorates with storage time of spent fuel and of separated plutonium, due to the decay of $^{241}Pu$, the best fissile isotope, into americium, a neutron absorber. The loss of fissile value of plutonium is more pronounced for usage in LWRs than in FBR. However, keeping the current plutonium inventory for an expected future deployment of FBRs is counterproductive. Recycling plutonium reduce the required volume for final disposal in an underground repository and the cost of final disposal. However, the benefits of utilizing an energy resource and of reducing final disposal liabilities are not the only aspects that determine the choice of a back-end policy.