• Korean Journal of Soil Science and Fertilizer
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• v.23 no.1
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• pp.15-20
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• 1990

A laboratory experiment was conducted to investigate the relationship between the composition of phosphorus forms and soil chemical properties. The soil samples were collected from the farms of the 149 locations where vegetables were intensively cultivated with heavy application of phosphorus. The composition percentages of Ca-P and Saloid-P to the total phosphorus were increased as increasing soil pH while those of Fe-P and Al-P were decreased, The composition percentage of Fe-P were increased up to pH 5.0-6.0 and decreased as increasing pH above 6.0. respectively. The pH dependency of Al-P and Fe-P composition percentage was more remarkable for the soils with high available phosphorus (>500ppm) than with low available phosphorus (<500ppm). Composition percentages were in order of Fe-P>Al-P>Ca-P>Saloid-P for the soils with available phosphorus below 500ppm, while those were in order of Al-P>Fe-P>Ca-P>Saloid-P for the soils with high available phosphorus above 1,000ppm. Composition percentages of Al-P and Fe-P were increased as increasing active Al content, and Fe-P was increased as increasing of active Fe and P sorbed but saloid-P, Al-P and Ca-P were decreased.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.2
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• pp.135-146
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• 2015

This paper is the fourth on the combustion characteristics of the landfill gas in a constant volume combustion chamber for a large displacement volume commercial engine and the second dealing with torch ignition. It discusses the combustion characteristics of torch ignition on the basis of the heat release and visualization. The results show that the jet and/or spout from the torch promote combustion by accelerating the flame front in the main combustion chamber. In addition, a hot gas jet exists when the orifice diameter is 4 mm, whereas the flame passes directly through the orifice if the diameter is 6 mm or greater. In addition, the effect of torch ignition differs according to the combination of the methane fraction, torch volume, and orifice size because various combustion processes occur as a result of the interaction of these parameters. Finally, it was found that the most suitable torch should have an orifice diameter of not less than 6 mm and an area ratio of not more than 0.15 to secure a consistent combustion process in a real engine.

• Journal of Energy Engineering
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• v.2 no.3
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• pp.258-267
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• 1993

A mathematical model has been developed to describe heat transfer phenomena in a PCM (phase change material) module for development of an energy recovery system. The PCM module, melting point of which is around 1673 K, consists of silicon(96.8%), aluminium(2.7%) and marginal amounts of impurities such as Ca, Fe and Ti. The module is covered by a capsule that consists of SiC(58%) and graphite(42%). Physical properties that are required for model predictions were cited from the references. The apparent capacity method and the postiterative method wert used in the mathematical model to describe the phase changing mechanism. Temperature and velocity of fluid are the major variables in the model calculation. For the gas temperature of 1773 K that simulates real operating conditions, the prediction shows that PCM is rapidly melted to axial direction. However, for the gas temperature of 3000 K that is higher than the real conditions, PCM is melted rapidly to the radial direction. The gas velocity has no influence on the melting phenomena of the PCM except when the gas velocity is relatively low. At the low gas velocity asymmetry of the temperature profiles in PCM is obtained.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.3
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• pp.199-204
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• 2000

In this study, the ZnS nanosized thin films that could be used for fabrication of blue light-emitting diodes, electro-optic modulators, and n-window layers of solar cells were grown by the solution growth technique (SGT), and their structural and optical properties were examined. Based on these results, the quantum size effects of ZnS were systematically investigated. Governing factors related to the growth condition were the concentration of precursor solution, growth temperature, concentration of aq. ammonia, and growth duration. X-ray diffraction patterns showed that the ZnS thin film obtained in this study had the cubic structure ($\beta$-ZnS). When the growth temperature was $75^{\circ}C$, the surface morphology and the grain size uniformity were the best. The energy band gaps of samples were determined from the optical transmittance valued, and were shown to vary from 3.69 eV to 3.91 eV. These values were substantially higher than 3.65 eV of bulk ZnS, demonstrating that the quantum size effect of SGT grown ZnS is remarkable. Photoluminescence (PL) peaks were observed at the positions corresponding to the lower energy than that to energy band gap, illustrating that the surface states were induced by the ultra-fineness of grains in ZnS films. Particularly, for the first time, it is reported for the SGT grown ZnS that the PL peaks were shifted depending on the grain size.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.11
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• pp.781-790
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• 2014

Contaminants such as organic matters, nutrients and toxic chemicals in rivers and lakes with a weak flow rate are first removed from the water and accumulated in the sediments. Subsequently, they are released into the water column again, posing direct/indirect adverse effects on the water quality and aquatic ecosystems. In particular, phosphorus is known to accelerate the eutrophication phenomenon when it is released into the water column via physical disturbance and biological/chemical actions as one of important materials that determine the primary production of aquatic ecosystems and an element that is stored mainly in the sediments in the process of material circulation in the body of water. In this study, the effect on reducing phosphorus release in sediments was analyzed by applying different capping materials to lake water, where the effect of aquatic microorganisms is taken into account, and to distilled water, where the effect of microorganisms is excluded. The experimental results showed that capping with chemical materials such as Fe-gypsum and $SiO_2$-gypsum further reduced the phosphorus release by at least 40% compared to the control case. Composite materials like granule gypsum+Sand showed over 50% phosphorus release reduction effect. Therefore, it is determined that capping with chemical materials such as granule-gypsum and eco-friendly materials such as sand is effective in reducing phosphorus release. The changes in phosphorus properties in the sediments before and after capping treatment showed that gypsum input helped to change the phosphorus that is present in lake sediments into apatite-P, a stable form that makes phosphorus release difficult. Based on the above results, it is expected that the application of capping technology will contribute to improving the efficiency of reducing phosphorus release that occurs in river and lake sediments.

• Journal of Technology Innovation
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• v.20 no.3
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• pp.57-91
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• 2012

This paper investigates determinants of litigation success in the two distinctive types of patent litigations, ex-parte and inter-parte cases, which are brought in the process where a filed application becomes a valid patent right. We regress winning rates of patent applicants on the characteristics of firms, trials, patent lawyer, and patent itself, using a probit model with sample selections. The paper finds that the relative suit rate of a firm, time to be sued, changes of patent agents by applicants, and multiple agents among explanatory variables affect ex-parte reexamination and in-parte post-grant patent trials differently in the point of average marginal effects. These variables lower the probability of applicant's victory in the ex-parte cases, while they raise the probability in the inter-parte trials. However, the experience that agents represent applicants is a winning rate-increasing factor both in inter-parte and ex-parte reexamination, unexpectedly. This result cannot be applied to the entire domain of the variable, since sample selection effects are reflected in the result. The number of claim increases the winning probability of the applicant in the both types of patent litigations. This study has some limitations because it ignores the information on the legal person to which a patent agent belongs, and confined agent's experience to patent filing. We leave it future studies to investigate the effects of lawsuit experience of patent agent, and those of characteristics of the law firm to which individual patent lawyer is affiliated.

• Archives of design research
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• v.11
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• pp.48-58
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• 1995

In 1981. KOREA applied YEAR OF WORLD DISABLED DESIGNNATED BY UN as starting point to begin noticing disabled and gradually improve and understand the problems of the disabled.This study considering the income level and welfare level selected basic most widely used wheelchair as subject of study. Design Application of this study's main analysis are as follolVs 1. MAN-MACHINE INTERFACE STUDY ANALYSIS!Basic concept of wheelchair is for persons uncapable of move by sitting down. so main focus of study was considered on equipment which on chair. 2. WHEELCHAm MOVEMENT STUDY ANALYSISlThrough movement and test measurement which can be considered as basic study of Ergonomics, observe movement changes accordingly. 3. BACK(MAIN) WHEEL AND HANDRIM MOVEMENT ANALYSIS / Seat and wheel as the most important component of a wheelchair, study the relation of handrim and hand movement and test the most effective and comfortable handrim. Direction of the study was concerntrated on three areas, with results and information collected, would like to suggest design change of X type collapsible chair in areas of size of SEAT(air pocket type), HANDRIM(anti-slip hump), ARMHEST(transfer movement, rubber padding. accent), and HANDLE(adjustable, round type). The content started this study is only one small position of understanding the disabled. Also, the importance of one of many business of assisting disabled rehabilitation. (IJISABLED, REHABILITATION. APPROACH)

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.2
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• pp.147-156
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• 2017

The white cane, walking assistive device of visually impaired person, has disadvantages for acquiring the information by contacting obstacles directly and detecting low obstacle on the ground. Recently, new devices have been developing to solve these problems, but these were not widely used due to high price and appearance. Therefore, in this study, we developed two types of walking assistive shoes which were manufactured with infrared sensors, pressure sensors and vibrating motors. Two types of shoes were classified with single sensor (SS) and double sensor (DS) type according to the number of infrared sensor. To evaluate the effectiveness, we compared required time and number of collisions during walking with walking assistive shoes and white cane on obstacle area. As the results, required time was increased than white cane while number of collisions was decreased when walking with developed walking assistive shoes. In addition, required time and number of collisions was more reduced when using walking assistive device than white cane. Therefore, we suggests that developed walking assistive shoes can a great help to provide safe walking condition and reducing time to adapt new types of walking assistive shoes.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.2
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• pp.97-107
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• 2017

This study is the second investigation on the steady flow characteristics of an SI engine with a semi-edge combustion chamber as a function of the port shape with varying evaluation positions. For this purpose, the planar velocity profiles were measured from 1.75B, 1.75 times of bore position apart from the bottom of head, to 6.00B positions using particle - image velocimetry. The flow patterns were examined with both a straight and a helical port. The velocity profiles, streamlines, and centers of swirl were almost the same at the same valve lift regardless of the measuring position, which is quite different from the case of the pent-roof combustion chamber. All the eccentricity values of the straight port were out of distortion criterion 0.15 through the lifts and the position. However, the values of the helical port exceeded the distortion criterion by up to 4 mm lift, but decreased rapidly above the 3.00B position and the 5 mm lift. There always existed a relative offset effect in the evaluation of the swirl coefficient using the PIV method due to the difference of the ideal impulse swirl meter velocity profile assumption, except for the cylinder-center-base estimation that was below 4 mm of the straight port. Finally, it was concluded that taking the center as an evaluation basis and the assumption about the axial velocity profile did not have any qualitative effect on swirl evaluation, but affected the value owing to the detailed profile.

• Journal of Science and Technology Studies
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• v.15 no.2
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• pp.191-227
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• 2015

The supply-driven innovation system is encountering its limitation. At the same time, the needs for solving societal challenges occurring in people's lives are growing. Social problem-solving R&D programs have been attracting attention as a countermeasure to satisfy these needs. It is important to understand the social context of the occurring problems as well as the users facing the social challenges. Therefore, social problem-solving R&D programs have to explore the social challenge and users' needs, with emphasis on the collaboration with researchers and users in the development and implementation process. This study carries out comparative analysis between 'Korean Citizen-driven R&D project' and 'Japanese Research institute of Science and Technology for Society (RISTEX)' concerning goals, construction of program, and promotion processes. The two cases are similar regarding the objectives of social problem-solving and the strategy for user participation. However, there are differences between the characteristics of the projects and promotion processes. The RISTEX is performing social problem-solving R&D with a much wider perspectives than the Korean project. This is because the Korean project maintained the existing R&D system with the lens of the supply-driven system, even when approaching social problem-solving. Therefore, this limitation should be overcome by adopting support systems discarding the supply-driven perspective, through substantiality of user participation, maintenance of legal system, and commercialization of technologies.