• 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.

• International Journal of Fluid Machinery and Systems
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• v.4 no.1
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• pp.57-66
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• 2011

Radial-vaned air separators show a strong stall suppression effect in an axial flow fans. From a survey of existing literature on the effects and the author's data, a possible mechanism for the significant effects has been proposed here. The stall suppression is suggested to have been achieved by a combination of the following several effects; (1) suction of blade and casing boundary layers and elimination of embryos of stall, (2) separation and straightening of reversed swirling flow from the main flow, (3) induction of the fan main flow toward the casing wall and enhancement of the outward inclination of meridional streamlines across the rotor blade row, thus keeping the Euler head increase in the decrease in fan flow rate, and (4) reinforcement of axi-symmetric structure of the main flow. These phenomena have been induced and enhanced by a stable vortex-ring encasing the blade tips and the air separator. These integrated effects appear to have caused the great stall suppression effect that would have been impossible by other types of stall prevention devices. Thus the author would like to name the device "tip-vortex-ring assisted stall suppression device".

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.7
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• pp.831-840
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• 1999

In this work, an aerothermodynamic calculation model for cooled axial flow turbine blades with trailing edge ejection is suggested and a mean line performance analysis of a turbine stage with nozzle cooling is carried out. A unique model regarding the interaction between coolant and main gas is proposed, while existing correlations are adopted to predict viscous loss and blade outflow angle. The interactions considered are the heat transfer from main gas to coolant and the temperature and pressure losses by the mixing of two streams due to the trailing edge coolant ejection. For a stator blade without ejection, trailing edge loss calculated by the trailing edge analysis is compared with that calculated by loss correlation. The effect of heat transfer effectiveness of coolant passage on the mixing loss is analyzed. For a model turbine stage with nozzle cooling, parametric analyses are carried out to investigate the effect of main design variables(coolant mass flow ratio, temperature and ejection area) on the stage performance.

• Human Ecology Research
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• v.51 no.3
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• pp.341-353
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• 2013

The object of this study is to examine the relationship between temperament (emotionality, activity, sociability, and shyness) and the resilience (social competence and language ability) of preschool children from low-income families and the moderating effect of maternal warmth. The subjects were 86 low-income preschool children (42 girls and 44 boys; mean age, 70.57 months), their mothers and teachers, recruited from five daycare centers in Namyangju city and Ansan city located in Gyeonggi-do area. Each child's language ability was individually assessed with with the standardized measure, Preschool Receptive-Expressive Language Scale (PRES) and their teachers reported on children's social competence and parents reported on their child's temperament by questionnaire. The collected data was analyzed by correlation analysis and hierarchical regression. The main results of this study were as follows. First, children's emotionality in temperament and maternal warmth had main effects on social competence. Second, only monthly income level and sex had main effects on language ability. Third, maternal warmth moderated the effects of children's shyness in temperament on social competence and language ability as resilience. Findings could provide basic information for programs to promote resilience in preschool children from low-income families.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.5
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• pp.1055-1062
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• 1988

The characteristics of tool wear and the machinability in cutting of GFRP have been studied. The wear behavior of carbide insert tools(P20, M10, K10) and Cermet in TiC grade was studied by turning of changing the cutting condition. Machinability could be estimated as the following empirical formula, CT$^{n}$ =W The main results obtained are as follows: (1) Dependence of rate of tool wear on cutting speed; with increases of cutting speed, the rate of tool wear initially increases gradually(1st range), then it increases proportionally to cutting speed(2nd range), and finally the rate is constant(3rd range). (2) When the contact length has a main, effect on tool wear, the cutting speed does nit affect the tool wear. On the contrary, the cutting speed has a main effect on tool wear, the contact length does not affect the tool wear. (3) The order of machinability is K10, M10, P20 and Cermet in TiC grade.

• Journal of Korea Society of Digital Industry and Information Management
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• v.17 no.4
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• pp.161-175
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• 2021

This study analyzed the efficiency and influence factors according to the main research institute type of R&D Program for the local community problem-solving. This study applied data envelopment analysis (DEA) method and Tobit regression analysis by using 20 institutions that participated in R&D Program. The results are summarized as follows. First, Analysis results according to the research institute type of R&D project, Efficient DMUs showed more regional innovation institutions than social economy enterprises. But regional innovation institutions were the lowest in the CCR and BCC model. However, efficiency dose not differ between regional innovation institutions and social economy enterprises. Second, as a result of the analysis relation between efficiency and allocation characteristics of R&D input, the participation of regional innovation organizations as participating organizations has a negative effect on efficiency. It was found that the higher the proportion of government subsidies and the higher the employment rate of the vulnerable, which is a social achievement, the positive effect on efficiency. The implication of this study is that the participation of social economy enterprises as the main R&D institution and government R&D support can provide social economy enterprises with opportunities to accumulate R&D capabilities and experience successful commercialization.

• Korean Journal of Acupuncture
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• v.38 no.1
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• pp.1-7
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• 2021

Objectives : In the meridian pathway system, 5 yang meridians excluding bladder meridian pass ST12. In this study, we tried to find out why 5 yang meridians pass ST12. Methods : 15 classics of acupuncture and moxibustion literature - 『Huangdimingtangjingjixiao』, 『Zhenjiujiayijing』, 『Huangdineijingtaisu』, 『Beijiqianjinyaofang』, 『Waitaimiyaofang』, 『Ishimpo』, 『Taipingshenghuifang』, 『Tongrenshuxue-zhenjiutujing』, 『Zhenjiuzishengjing』, 『Shisijingfahui』, 『Zhenjiujuying』, 『Yixuerumen』, 『Zhenjiudacheng』, 『Leijing』, and 『Leijingtuyi』- were reviewed and compared. Results : Five yang meridians passed ST12, and large intestine meridian and triple energizer meridian were closely related to ST12 in divergent channels. Stomach meridian and gall bladder meridian were related to ST12 in meridian muscles. ST12 was related to small intestine meridian in main cure effect. ST12 is in the best position to enter the body cavity. Conclusions : It can be seen that ST12 is closely related to all internal organs through the characteristics of stomach meridian. Therefore, it is thought that ST12's various characteristics largely explains a pathway to enter the body cavity in the hand and foot three yang meridians.

• Asian Journal of Business Environment
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• v.12 no.3
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• pp.13-22
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• 2022

Purpose: The research aims to analyze the export performance of processed seaweed, its competitiveness, and determinants on seven main destination countries. Research design, data and methodology: The study uses data of seven main destination countries of Indonesian processed seaweed from 2010 to 2019. For competitiveness analysis, the study uses Revealed Comparative Advantage, Export Product Dynamics, and X-Model of Potential Export Product. Results: The study reveals that the export performance has decreased on all five countries except for Japan and USA. The X-Model analysis shows that the market classification has increased or been stable in every country except for Germany and France. GDP per capita of each destination country and competitiveness index have positive and significance effect while other factors have negative and significance effect. Conclusions: In 2019, Indonesia's processed seaweed market in Japan, United States, and France are on potential market, while Singapore and Italy are on optimistic market. In the future, Indonesia's processed seaweed export can be focused more on countries that have a good market potential. To improve the export volume, GDP per capita of destination country, and competitiveness index of Indonesian processed seaweed should be higher, while export price, economic distance, and real exchange rate should be lower.

• Journal of Ocean Engineering and Technology
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• v.37 no.1
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• pp.31-37
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• 2023

In this study, a fiber chain was developed to replace a steel chain using high-modulus polyethylene DM20. The pick count, wrapping count, and inner length were selected as the main design variables of the fiber chain and were analyzed to increase the breaking strength. Orthogonal array experiments were conducted, and the results were analyzed with respect to the breaking strength. The analysis revealed that the pick count and wrapping count had meaningful effects at significance levels within 5%. The main effect analysis revealed that a smaller pick count, larger wrapping count, and longer inner length caused the breaking strength to increase. With the wrapping count fixed at 1, a pick count less than -0.65, and an inner length greater than 0.38, the breaking strength was calculated to be greater than 300 kN. These results are expected be important factors in the derivation of an optimal combination of design variables to attain a fiber chain with a targeted strength.

• Journal of Forest and Environmental Science
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• v.39 no.2
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• pp.96-104
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• 2023

The successful restoration program requires a comprehensive understanding of variables influencing seedling efficiency. Below-ground is hypothesized to have a major impact on seedling performance of species when planted in agriculture, and degraded areas with different types of mulching. This study investigated on Sg. Terla Forest Reserve in Cameron Highlands Pahang, Malaysia. In this study randomized complete block design (RCBD) was used. The excavation method was applied to study the root system development, above, and below ground biomass distributions under different types of mulching: coconut mulching (CM), oil palm mulching (OM), plastic mulching (PM) and control (CK). The root diameter, main root length, lateral root length, root coiling, and root direction toward to sun were recorded. The results in this study indicate that mulching had significant effect on root diameter, main root length, and root distributions among treatments while for lateral root length, root: shoot ratio, dry biomass distributions, and above and below ground biomass did not showed significant effect among treatments. The highest values for root diameter, lateral root length, main root length, root distributions, dry biomass distributions and above and below ground biomass were showed in CM treatments. However 75% of root coiling was observed in seedlings between treatments.