• Title/Summary/Keyword: Enhancement of Performance

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Noncondensable gas's influence in waster vapor absorption accompanying interfacial disturbance into aqueous solution of LiBr

  • Dong-Ho RIE;Keun-Oh Lee
    • Journal of the Korean Society of Safety
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    • v.7 no.2
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    • pp.63-70
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    • 1992
  • The aim of this research is to obtain a basic quantitative understanding of the effect of a noncondensable gas on the absorption of water vapor by a $H_2O$ / LiBr combination with n-octanol as the surfactant. Nonflowing aqueous solutions of LiBr (40,45,50 mass%) were exposed to saturated water vapor following the addition of an n-octanol sufactant (0.01 and 0.6 mass%). A small amount of a noncondensable gas (air) was allowed into the absorber (0.03 volume%) and its effect was analyzed by measuring the amount of water vapor absorbed. This study will aid to predict the performance of heat pump and safety operating condition when the noncondensable gas is not allowed in the absorber The results indicate that, in the presence of small amounts of a noncondensable gas, vapor absorption enhancement ratios are less than half o( those obtained under the same experimental conditions when a noncondensable gas is not present (1). The presence of a noncondensable gas causes the partial vapor pressure of air to increase at the vapor / liquid interface, which results in an instability of vapor absorption rate nd. hence, in an inhibition of interfacial disturbance.

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Preparation of Silica Nanoparticles via Recycling of Silicon Sludge from Semiconductor Dicing Process and Electro-responsive Smart Fluid Application (반도체 다이싱 공정에서 발생하는 실리콘 슬러지를 재활용한 실리카 나노입자의 제조 및 전기감응형 유체로의 응용)

  • Yeon-Ryong Chu;Suk Jekal;Jiwon Kim;Ha-Yeong Kim;Chan-Gyo Kim;Minki Sa;Hyung Sub Sim;Chang-Min Yoon
    • Journal of the Korea Organic Resources Recycling Association
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    • v.31 no.3
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    • pp.15-25
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    • 2023
  • In this study, silicon sludge from semiconductor dicing process is recycled to fabricate silica nanoparticles, which are applied as dispersing materials for electro-responsive (ER) smart fluid. In specific, metal impurities are removed from silicon sludge by acid washing to obtain the high-purity silicon powder. And then, silica nanoparticles are synthesized by facile hydrothermal method employing the silicon powder as reactant material. To control the size of silica nanoparticles, the reaction time of hydrothermal method is varied as 8, 15, 20, and 30 hours are applied to control the size of silica nanoparticles. Sizes of silica nanoparticles are increased proportionally to the reaction time owing to the increased numbers of hydrolysis and condensation reactions. As-synthesized silica nanoparticles are prepared as electro-responsive smart fluids by dispersing into silicon oil. Silica nanoparticles synthesized by 30 hours of hydrothermal reaction (SiO2-H30) exhibit the highest shear stress of 21.4 Pa under an applied electric field strength of 3.0kV mm-1. Such enhancement in ER performance of SiO2-H30 among various silica nanoparticles are attribute to the reinforcing effect originated from the mixed particle size, which allowing the formation of rigid chain-like structures. Accordingly, this study successfully propose a recycling method of silicon sludge to synthesize silica nanoparticles and their derived ER fluids, which may suggest new possibility to ESG management emphasizing the eco-friendliness.

Implications of Shared Growth of Public Enterprises: Korea Hydro & Nuclear Power Case (공공기관의 동반성장 현황과 시사점: 한국수력원자력(주) 사례를 중심으로)

  • Jeon, Young-tae;Hwang, Seung-ho;Kim, Young-woo
    • Journal of Venture Innovation
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    • v.4 no.2
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    • pp.57-75
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    • 2021
  • KHNP's shared growth activities are based on such public good. Reflecting the characteristics of a comprehensive energy company, a high-tech plant company, and a leading company for shared growth, it presents strategies to link performance indicators with its partners and implements various measures. Key tasks include maintaining the nuclear power plant ecosystem, improving management conditions for partner companies, strengthening future capabilities of the nuclear power plant industry, and supporting a virtuous cycle of regional development. This is made by reflecting the specificity of nuclear power generation as much as possible, and is designed to reflect the spirit of shared growth through win-win and cooperation in order to solve the challenges of the times while considering the characteristics as much as possible as possible. KHNP's shared growth activities can be said to be the practice of the spirit of the times(Zeitgeist). The spirit of the times given to us now is that companies should strive for sustainable growth as social air. KHNP has been striving to establish a creative and leading shared growth ecosystem. In particular, considering the positions of partners, it has been promoting continuous system improvement to establish a fair trade culture and deregulation. In addition, it has continuously discovered and implemented new customized support projects that are effective for partner companies and local communities. To this end, efforts have been made for shared growth through organic collaboration with partners and stakeholders. As detailed tasks, it also presents fostering new markets and new industries, maintaining supply chains, and emergency support for COVID-19 to maintain the nuclear power plant ecosystem. This reflects the social public good after the recent COVID-19 incident. In order to improve the management conditions of partner companies, productivity improvement, human resources enhancement, and customized funding are being implemented as detailed tasks. This is a plan to practice win-win growth with partner companies emphasized by corporate social responsibility (CSR) and ISO 26000 while being faithful to the main job. Until now, ESG management has focused on the environmental field to cope with the catastrophe of climate change. According to KHNP is presenting a public enterprise-type model in the environmental field. In order to strengthen the future capabilities of the nuclear power plant industry as a state-of-the-art energy company, it has set tasks to attract investment from partner companies, localization and new technologies R&D, and commercialization of innovative technologies. This is an effort to develop advanced nuclear power plant technology as a concrete practical measure of eco-friendly development. Meanwhile, the EU is preparing a social taxonomy to focus on the social sector, another important axis in ESG management, following the Green Taxonomy, a classification system in the environmental sector. KHNP includes enhancing local vitality, increasing income for the underprivileged, and overcoming the COVID-19 crisis as part of its shared growth activities, which is a representative social taxonomy field. The draft social taxonomy being promoted by the EU was announced in July, and the contents promoted by KHNP are consistent with this, leading the practice of social taxonomy

Development and Application of the Explicit and Reflective Learning Strategy for Enhancement of the Elementary School Students' Basic Inquiry Skills -Based on Observation and Classification- (초등학생의 과학탐구기능 향상을 위한 명시적이고 반성적인 교수.학습전략 개발 및 적용 -관찰과 분류를 중심으로-)

  • Lee, Hye-Won;Min, Byeong-Mee;Son, Yeon-A
    • Journal of The Korean Association For Science Education
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    • v.32 no.1
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    • pp.95-112
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    • 2012
  • The research evaluated the effects of the improvements in scientific inquiry for elementary school students and focused on the development and application of the explicit and reflective learning strategy through observation and classification. The explicit and reflective learning strategy was modified and completed with the review of the experts after the development of the draft based on the theoretical approach. The students were evaluated for their academic achievements in scientific inquiry skills before and after taking the course. The results were as follows: First, the steps of the developed learning strategy (1) to motivate, (2) to explore reflectively, (3) to guide explicitly, (4) to inquire explicitly, and (5) to verify reflectively were set to reflect the verification. Second, the results of applying the developed model to the lessons based on the quantitative analysis was effective for observation and classification skills in the quest for improved performance of the whole (the sum of observation and classification, inquiry skills) and the observed features, but there was no effect on classification. Also, the lessons applied the developed teaching strategy and showed effectiveness in improving academic achievement. Particularly in analyzing the relationship between the academic achievement and exploration capabilities, in order to improve academic achievement, the importance of improving inquiry skills was found. Third, the qualitative analysis of teaching and learning strategy developed by applying the lessons of this teacher guide and small group activities through the explicit and reflective observation and classification of the student learning activities showed the significant improvement of ability of the scientific inquiry skills. In addition to the improvement in the abilities of the classification showed after the formation of the most basic observation skills of the scientific inquiry.

Long-term Evaluation of Muscle Quality of the Olive Flounder, Paralichthys olivaceus, Fed with Extruded Pellet (배합사료로 장기간 사육된 넙치의 육질평가)

  • Kim, Kang-Woong;Kang, Yong-Jin;Kim, Kyoung-Duck;Choi, Se-Min;Lee, Jong-Yun;MoonLee, Hae-Young;Bai, Sung-Chul C.
    • Journal of Aquaculture
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    • v.20 no.1
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    • pp.51-55
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    • 2007
  • This study was conducted to evaluate the muscle quality of the olive flounder fed on extruded pellet (EP) diets compared with a raw fish moist pellet (MP) diet for olive flounder, Paralichthys olivaceus in a commercial scale for a year. The sensory and physical qualities and palatable compounds were compared for evaluation of muscle quality in fish. Four diets were formulated for this experiment: two experimental EP diets (EP 1 and 2), one commercial EP diet (CEP) and MP diet. Crude lipid of fish fed EP1 and EP2 was significantly higher (P<0.05) than that of fish fed CEP, but not significantly different from that of fish fed MP (P>0.05). In the palatable compounds, the free amino acids composition were much alike in that of all the diets. Proline, glycine and alanine from fish fed diet EPs were the most abundant compound among amino acid compositions. There was little difference in the free amino acid compositions of all flounder from localities and the growing conditions between wild and cultured fishes. Taurine of fish fed EP1 was dominantly high over that of fish fed EP2, CEP and MP. In all nucleotides and their related compounds, ATP and IMP from fish fed EP diets were higher (P<0.05) than those of fish fed MP. In the sensory score, overall-acceptability of fish fed EP2 were significantly higher (P<0.05) than that of fish fed EP1, CEP and MP. Hardness of physical properties from fish fed EP2 was significantly higher (P<0.05) than those of fish fed CEP (P<0.01). These results strongly suggest that diets EP could be developed to replace MP diet for the grow-out stage of olive flounder without adverse effect on growth performance.

Variations of Isoflavone Contents in Seeds and Sprouts of Sprout Soybean Cultivars (나물용 콩 품종의 종실 및 콩나물 함유 Isoflavone 변이)

  • Kim, Young-Jin;Oh, Young-Jin;Cho, Sang-Kyun;Kim, Jung-Gon;Park, Myoung-Ryoul;Yun, Song-Joong
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.51 no.spc1
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    • pp.160-165
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    • 2006
  • Biofuctionality of soybean seeds and soy-bean products have been fortified by the uncovering of the multifuctional beneficial effects of isoflavones. As one way to fully utilize beneficial effects of isoflavones in soybean sprout is through the enhancement of isoflavone contents in soybean seeds, genetic selection for higher isoflavone and cultivational measures to increase isoflavone content in soybean seeds were attempted. Isoflavones (daidzein, gemstein) contents in soybean seeds and soybean sprouts were determined by high performance liquid chromatography. Total isoflavone contents in soybean seeds ranged from 756 to $1,682{\mu}g/g$ and Iksan #13 $(1,682{\mu}g/g)$ showed highest content among the 21 germplasms analyzed. Onetime treatment of soybean plants with Antipol or Piaster at the $V_4$ stage yielded seeds with higher isoflavones as $2,472{\mu}g/g\;or\;2,052{\mu}g/g$, respectively, which were higher by 37% and 14% than that of seeds in the control plants, respectively. In Eunhakong, Isoflavone contents of soybean sprout changed during sprouting. Daidzein content in hypocotyl increased to maximum on the third day of cultivation and decreased there-after, whereas the content changed little in cotyledon. In sprouts of Pungsannamulkong, daidzein content in hypocotyl showed a maximum level on the first day and decreased gradually thereafter but, the content changed little in cotyledon. Total isoflavone contents in lateral roots which developed on the 6th day after sprouting ranged from 4,416 to $5,232{\mu}g/g$ DW.

Ammonia Decomposition over Ni Catalysts Supported on Zeolites for Clean Hydrogen Production (청정수소 생산을 위한 암모니아 분해 반응에서 Ni/Zeolite 촉매의 반응활성에 관한 연구)

  • Jiyu Kim;Kyoung Deok Kim;Unho Jung;Yongha Park;Ki Bong Lee;Kee Young Koo
    • Journal of the Korean Institute of Gas
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    • v.27 no.3
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    • pp.19-26
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    • 2023
  • Hydrogen, a clean energy source free of COx emissions, is poised to replace fossil fuels, with its usage on the rise. Despite its high energy content per unit mass, hydrogen faces limitations in storage and transportation due to its low storage density and challenges in long-term storage. In contrast, ammonia offers a high storage capacity per unit volume and is relatively easy to liquefy, making it an attractive option for storing and transporting large volumes of hydrogen. While NH3 decomposition is an endothermic reaction, achieving excellent low-temperature catalytic activity is essential for process efficiency and cost-effectiveness. The study examined the effects of different zeolite types (5A, NaY, ZSM5) on NH3 decomposition activity, considering differences in pore structure, cations, and Si/Al-ratio. Notably, the 5A zeolite facilitated the high dispersion of Ni across the surface, inside pores, and within the structure. Its low Si/Al ratio contributed to abundant acidity, enhancing ammonia adsorption. Additionally, the presence of Na and Ca cations in the support created medium basic sites that improved N2 desorption rates. As a result, among the prepared catalysts, the 15 wt%Ni/5A catalyst exhibited the highest NH3 conversion and a high H2 formation rate of 23.5 mmol/gcat·min (30,000 mL/gcat·h, 600 ℃). This performance was attributed to the strong metal-support interaction and the enhancement of N2 desorption rates through the presence of medium basic sites.

A Study on the Adsorption and Desorption Characteristics of Metal-Impregnated Activated Carbons with Metal Precursors for the Regeneration and Concentration of Ammonia (암모니아의 재생 및 농축을 위한 금속 전구체에 따른 금속 첨착 활성탄의 흡착 및 탈착 특성에 관한 연구)

  • Cho, Gwang Hee;Park, Ji Hye;Rasheed, Haroon Ur;Yoon, Hyung Chul;Yi, Kwang Bok
    • Clean Technology
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    • v.26 no.2
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    • pp.137-144
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    • 2020
  • Metal-impregnated activated carbons were prepared via ultrasonic-assisted impregnation method for regeneration and low ammonia concentration. Magnesium and copper were selected as metals, while chloride (Cl-) and nitrate (NO3-) precursors were used to impregnate the surface of activated carbon. The physical and chemical properties of the prepared adsorbents were characterized by TGA, BET, and NH3-TPD. The ammonia breakthrough test was carried out using a fixed bed and flowing ammonia gas (1000 mg L-1 NH3, balanced N2) at 100 mL min-1, under conditions of temperature swing adsorption (TSA) and pressure swing adsorption (PSA, 0.3, 0.5, 0.7, 0.9 Mpa). The adsorption and desorption performance of ammonia were in the order of AC-Mg(Cl) > AC-Cu(Cl) > AC-Mg(N) > AC-Cu(N) > AC through NH3-TPD and TSA and PSA processes. AC-Mg(Cl) using MgCl2 showed the average adsorption amount of 2.138 mmol/g at TSA process. Also, AC-Mg(Cl) showed the highest initial adsorption amount of 3.848 mmol/g at PSA 0.9 Mpa. When metal impregnated the surface of the activated carbon, it was confirmed that not only physical adsorption, but also chemical adsorption increased, making enhancement in adsorption and desorption performances possible. Also, the prepared adsorbents showed stable adsorption and desorption performances despite repeated processes, confirming their applicability in the TSA and PSA processes.

The Reserch on Actual Condition of Crime of Arson Which Occurs in Korea and Its Countermeasures (방화범죄의 실태와 그 대책 - 관심도와 동기의 다양화에 대한 대응 -)

  • Choi, Jong-Tae
    • Korean Security Journal
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    • no.1
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    • pp.371-408
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    • 1997
  • This article is the reserch on actual condition of crime of arson which occurs in Korea and its countermeasures. The the presented problem in this article are that (1) we have generally very low rate concern about the crime of arson contrary to realistic problems of rapid increase of crime of arson (2) as such criminal motives became so diverse as to the economic or criminal purpose unlike characteristic and mental deficiency of old days, and to countermeasure these problems effectively it presentation the necessity of systemantic research. Based on analysis of reality of arson, the tendency of this arson in Korea in the ratio of increase is said to be higher than those in violence crime or general fire rate. and further its rate is far more greater than those of the U.S.A. and Japan. Arson is considered to be a method of using fire as crime and in case of presently residence to be the abject, it is a public offense crime which aqccompany fatality in human life. This is the well It now fact to all of us. And further in order to presentation to the crime of arson, strictness of criminal law (criminal law No, 164 and 169, and fire protection law No. 110 and 111) and classification of arsonist as felony are institutionary reinforced to punish with certainty of possibility, Therefore, as tendency of arson has been increased compared to other nations, it is necessary to supplement strategical policy to bring out overall concerns of the seriousness of risk and damage of arson, which have been resulted from the lack of understanding. In characteristics analysis of crime of arson, (1) It is now reveald that, in the past such crime rate appeared far more within the boundary of town or city areas in the past, presently increased rate of arsons in rural areas are far more than in the town or small city areas, thereby showing characteristics of crime of arson extending nation wide. (2) general timetable of arson shows that night more than day time rate, and reveald that is trait behavior in secrecy.(3) arsonists are usually arrested at site or by victim or report of third person(82,9%).Investigation activities or self surrenders rate only 11.2%. The time span of arrest is normally the same day of arson and at times it takes more than one year to arrest. This reveals its necessity to prepare for long period of time for arrest, (4) age rate of arson is in their thirties mostly as compared to homicide, robbery and adultery, and considerable numbers of arsons are in old age of over fifties. It reveals age rate is increased (5) Over half of the arsonists are below the junior high school (6) the rate of convicts by thier records is based on first offenders primarily and secondly more than 4 time convicts. This apparently shows necessity of effective correctional education policy for their social assimilation together with re-investigation of human education at the primary and secondary education system in thier life. The examples of motivation for arosnits, such as personal animosity, fury, monetary swindle, luscious purpose and other aims of destroying of proof, and other social resistance, violence including ways of threatening, beside the motives of individual defects, are diverse and arsonic suicide and specifically suicidal accompany together keenly manifested. When we take this fact with the criminal theory, it really reveals arsons of crime are increasing and its casualities are serious and a point as a way of suicide is the anomie theory of Durkheim and comensurate with the theory of that of Merton, Specifically in the arson of industrial complex, it is revealed that one with revolutionary motive or revolting motive would do the arsonic act. For the policy of prevention of arsons, professional research work in organizational cooperation for preventive activities is conducted in municipal or city wise functions in the name of Parson Taskforces and beside a variety of research institutes in federal government have been operating effectively to countermeasure in many fields of research. Franch and Sweden beside the U.S. set up a overall operation of fire prevention research funtions and have obtained very successful result. Japan also put their research likewise for countermeasure. In this research as a way of preventive fire policy, first, it is necessary to accomodate the legal preventitive activities for fire prevention in judicial side and as an administrative side, (1) precise statistic management of crime of arson (2) establishment of professional research functions or a corporate (3) improvement of system for cooperative structural team for investigation of fires and menpower organization of professional members. Secondly, social mentality in individual prospect, recognition of fires by arson and youth education of such effect, educational program for development and practical promotion. Thirdly, in view of environmental side, the ways of actual performance by programming with the establishment of cooperative advancement in local social function elements with administrative office, habitants, school facilities and newspapers measures (2) establishment of personal protection where weak menpowers are displayed in special fire prevention measures. These measures are presented for prevention of crime of arson. The control of crime and prevention shall be prepared as a means of self defence by the principle of self responsibility Specifically arsonists usually aims at the comparatively weak control of fire prevention is prevalent and it is therefore necessary to prepare individual facilities with their spontaneous management of fire prevention instead of public municipal funtures of local geverment. As Clifford L. Karchmer asserted instead of concerns about who would commit arson, what portion of area would be the target of the arson. It is effective to minister spontaveously the fire prevention measure in his facility with the consideration of characteristics of arson. On the other hand, it is necessary for the concerned personnel of local goverment and groups to distribute to the local society in timely manner for new information about the fire prevention, thus contribute to effective result of fire prevention result. In consideration of these factors, it is inevitable to never let coincide with the phemonemon of arsons in similar or mimic features as recognized that these could prevail just an epedemic as a strong imitational attitude. In processing of policy to encounter these problems, it is necessary to place priority of city policy to enhancement of overall concerns toward the definitive essense of crime of arson.

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COMPLIANCE STUDY OF METHYLPHENIDATE IR IN THE TREATMENT OF ADHD (주의력결핍과잉행동장애 치료 약물 Methylphenidate IR의 순응도 연구)

  • Hwang, Jun-Wan;Cho, Soo-Churl;Kim, Boong-Nyun
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.15 no.2
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    • pp.160-167
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    • 2004
  • Objectives : There have been very few studies on the compliance of methylphenidate-immediate releasing form(MPH-IR), which is the most frequently used drug in Korea, in Attention Deficit Hyperactivity Disorder(ADHD). This study was conducted to investigate the compliance rate and the related factors in the one year pharmacotherapy process via OPD for children with ADHD. Method : Total 100 ADHD patients were selected randomly among patients who have been treated with MPH-IR from September in 2002 to December in 2002. All the selected patients were diagnosed with DSM-IV-ADHD criteria and fulfilled the inclusion criteria. In March, 2003(at the time of 6 month treatment), all the patients and parents received the questionnaire for the compliance and satisfaction for MPH-IR treatment. In October 2003(at time of 1 year treatment), we, investigators evaluated the socio-demographic variables, developmental data, medical data, family data, comorbid disorders, treatment variables, and compliance rate. Through these very comprehensive data, The compliance rate at the time of mean 1 year treatment and the related factors were investigated. Result : 1) In the questionnaire for compliance and satisfaction for MPND treatment, the 60% of respondents(parents) reported more than moderate degree of satisfaction in the effectiveness of MPND. Their compliance rate for the morning prescription was 81%, but the rate of afternoon prescription was 43%. 2) In the evaluation at the time of 1 year treatment(October 2003), the 38% of parents were dropped out from the OPD treatment. The mean compliance rate for the 1 year treatment was 62%. the 38% of parents were dropped out from the OPD treatment. The mean compliance rate for the 1year treatment was 62%. 3) Compared with the noncompliant group(drop-out group), compliant group showed higher total, verbal and performance IQ scores. In the treatment variables, higher reposponder rate(clinician rating), higher medication dosage and more compliance rate in afternoon prescription were found in the compliant group compared with the noncompliant group. There were no statistical differences in the demographic variables(age, sex, SES, parental education level), medical data, developmental profiles and academic function. Conclusion : To our knowledge, this is the first report about the compliance rate of the MPH-IR treatment for the children with ADHD. The compliance rate at the time of mean 1year treatment was 62%, which was comparable with other studies performed in foreign countries, especially States. In this study, the compliance related factors were IQ score, clinical treatment response, dosage of MPH-IR, and early compliance for the afternoon prescription. These results suggest that clinician plan the strategies for the promotion of the early compliance for the after prescription and enhancement of overall treatment response.

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