• Applied Chemistry for Engineering
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• 제5권1호
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• pp.139-148
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• 1994

The partial oxidation of methane with nitrous oxide on silica-supported metal-oxygen cluster compounds, known as heteropoly acids, has been studied. The effects of several variables such as reaction temperature, partial pressure of reactants, residence time, loading of the catalysts, and pretreatment temperature, on the conversion and product distribution were observed. The kinetics also has been studied. The conversion and yield of formaledehyde show maximum values at a loading of 20 wt%. The apparent reaction order of methane conversion is ca. 1.0 with respect to $CH_4$ and ca. 0.4 with respect to $N_2O$. In addition, the apparent activation energy is 30.78 kcal/mole. The addition of small quantities methane whereas water introduced to the reactant decreased the activity of catalyst under present study.

• Journal of the Economic Geographical Society of Korea
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• 제12권3호
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• pp.277-290
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• 2009

This paper aims to draw essential facts of network city, to analyze the urban corridor in South-East region, Korea, as a network city. Firstly, the characteristics of the network city is examined theoretically. The global economy is developing an innovative class of network cities. A network cities evolve when two or more previously independent cities, potentially complementary in function, strive to cooperate and achieve significant scope economies aided by-fast and reliable transport and communications infrastructure. Network Cities place a higher priority on knowledge-based activities like research, education and the creative arts. Each constituting city stands to benefit from the synergies of interactive growth via reciprocity, knowledge exchange and unexpected creativity. Secondly, we discussed the network structure of cities in South-East region, Korea itself intensively. We survey the network location and outline of the urban corridor in South-East region, spatial specialization and interaction between the constituting cities. We also discussed the problems of the network cities in South-East region, Korea and introduced the desirable policies and alternatives. We can ascertain from the case study of cities in South-East region that the cities in South-East region corresponds the network city model fairly.

• Journal of the Korean Geographical Society
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• 제40권6호
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• pp.653-670
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• 2005

The purpose of this study is to explore a spatial agglomeration characteristics and innovative milieu of the shoemaking industry in Seoul. In order to explain it, currently discussed dynamic agglomeration economies approach is applied and as an example, shoemaking industry in Seoul has been analyzed. The result of this research can be boardly summarized into two points. Frist, agglomeration economy is changing from urbanization economy to localization economy in this newly rising core of shoemaking industry which is Sung-Su dong area. Also, cooperative effects based on collective efficiency between companies and people are being generated within the area. This is largely affected by networking infrastructure between companies and people within the area, non-trade dependency and social capital acclamation. Secondly, the lack of institutional agglomeration formation in this area is considered to be the obstacle for the long-term development and innovation spin-off. This means recognition switch-over and institutional concern and support is needed in the future from the public sector.

• Clinical and Experimental Pediatrics
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• 제63권8호
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• pp.321-328
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• 2020

Background: Pediatric hypertension is the main cause of morbidity and mortality in pediatric populations. Purpose: To examine pediatric hypertension in a clinical setting, we used the percentile rank approach and defined hypertension as that above the 95th percentile. Methods: The present study was linked to the a national analytical cross-sectional community-based Iranian Children and Adolescents' Psychiatric Disorders (IRCAP) survey. The survey was nationwide and funded by the National Institute of Medical Research Development. The IRCAP survey included 31,000 children and adolescents aged 6-18 years in all 31 Iran provinces. The current study included 1,035 children and adolescents and linked the data of the risk factors of cardiovascular disease only in Yazd province via random cluster sampling. Results: Of the total participants, 456 (44.1%) were male and 579 (55.9%) were female. The mean age was 11.2±3.8 years (11.7±3.7 years for males, 11.0±3.6 years for females), while mean height was 146±20.0 cm overall, 147.2±22.0 cm for males, and 144.6±17.0 cm for females (P=0.009). The blood pressure distributions and percentiles were evaluated. Conclusion: Here we determined age- and height-specific 50th, 90th, 95th, and 99th percentiles of systolic and diastolic blood pressures in Yazd boys and girls using 10-cm height intervals.

• KIEAE Journal
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• 제7권1호
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• pp.5-13
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• 2007

Since aging has become one of most hot and serious issues in the whole global world, universal design as a strategic concept to enable the elderly age in place has received much attention and its importance is getting recognized. Japan has undergone the Aging phenomenon much earlier than Korea and other countries. During that time, through much trials and errors, it accumulated the wisdoms and techniques to precede aging friendly environment and products. Therefore current Japan house is a comprehensive setting which embraces lots of universal design features that has a valuable implication for Korean development that faces fast aging future. The purpose of this study was to delineate characteristics of universal design features appeared in Japanese Model houses. One site of housing park in the city where various model houses of representative housing construction companies was selected as a cluster area for data collecting. Data were collected mainly through field survey at the housing park of Tokyo during November, 2006, and additional data were collected through website and company information of relevant company. Universal design features were extracted for 17 houses of the housing park and sorted and analyzed according to the analysis frame. The frame were made using 2 major clusters; space area, and 8 universal design principle. Results showed a range of universal design feature and its detail universal design principle satisfied. The 8 principle currently developed became to house realistic practical examples and theory became proved its impractical power. The academic, educational and industrial implication were documented.

• Journal of Energy Engineering
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• 제16권3호
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• pp.149-154
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• 2007

An experimental study on the air-side pressure drop of slit fin-tube heat exchanger has been carried out. The data reduction methodology for air-side pressure drop in the literature is not based on a consistent approach. This paper focuses on method of data reduction to obtain the air-side performance of fin-tube heat exchanger using R22 and recommends standard procedures for dry and wet surface pressure drop estimation in fin-tube heat exchanger. A comparison was made between the predictions of previously proposed empirical correlations and experimental data for the air-side pressure drop on design conditions of condenser and evaporator. Results are pre-sented as plots of friction f-factor against Reynolds number based on the fin collar outside diameter and compared with previous studies. The data covers a range of refrigerant mass fluxes of $150{\sim}250\;kg/m^2s$ with air flows at velocity ranges from 0.38 m/s to 1.6 m/s.

• Bulletin of the Korean Chemical Society
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• 제26권1호
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• pp.103-106
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• 2005

In order to investigate the catalytic mechanism for the growth of carbon nanotubes (CNTs), a comprehensive study was conducted using carbon materials synthesized at 680 ${^{\circ}C}$ with a gas mixture of CO-H$_2$ after reduction at 800 ${^{\circ}C}$ by H$_2$ gas from iron oxide, and metal Pt. The resulting material was observed by scanning electron microscopy (SEM) and X-ray diffraction patterns (XRD) after a variety of reaction times. The carbon materials synthesized by metal Pt were little affected by reaction time and the sintered particles did not form CNTs. Xray analysis revealed that metal Fe was completely converted to iron carbide (Fe$_3$C) without Fe peaks in the early stage. After 5 min, iron carbide (Fe$_3$C) and carbon (C) phases were observed at the beginning of CNTs growth. It was found that the intensity of the carbon(C) peak gradually increased with the continuous growth of CNTs as reaction time increases. It was also found that the catalyst of growth of CNTs was metal carbide.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제34권3호
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• pp.299-305
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• 2010

In general, the flexible forming die that has been used in the flexible forming process has the identical punch size; hence, its flexibility is relatively low because the range of allowable curvature radii is limited due to the uniform punch tip radius. Hence, a conceptual design of a sectional flexible die is presented for enhancing the flexibility of the forming process. Two punches of different sizes are used to configure the arbitrary forming surface. For a forming region with a relatively large curvature radius, a large punch array block is used; on the other hand, for the forming regions with small curvature radii, a small punch block is used. The cross-sectional profiles are compared with the target shape for evaluating the effectiveness of the process. Consequently, it is confirmed that the sectional flexible die can be used along with a combination of punch blocks of different sizes for manufacturing objective surfaces of complex shapes.

• Journal of the Ergonomics Society of Korea
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• 제32권3호
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• pp.237-243
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• 2013

Objective: The present study developed an estimation method of boundary zone representative humanoids(hereafter, EBZ method) using descriptive statistics on the design target population. Background: The boundary zone method(hereafter, BZ method) generates representative humanoids at a boundary zone that statistically accommodates a designated percent of the design target population; however, the BZ method has a practical limitation because it requires a large scale anthropometric database on the design target population. Method: The EBZ method developed in the present study consisted of 3 steps. In the first step, the boundary zone of accommodating a designated percent(e.g., 90%) is formed under the assumption of normal distributions for anthropometric sizes. In the second step, cases that fall within the boundary zone are estimated using descriptive statistics(mean, standard deviation, and covariance) on the design target population. In the last step, K-mean cluster analysis is conducted for the cases, and representative humanoids are selected from each of clusters. Results: Evaluation results showed that mean accommodation percent of the EBZ method was 90.9%(range: 90.8~91.1%) which is similar to the target percent(90%). In addition, standard deviation of accommodation percent for 100 repetitions was 0.1%. Lastly, the number of representative humanoids generated by the EBZ method(n = 20) was similar to the BZ method(n = 16). Conclusion: The EBZ method can generate representative humanoids which accommodate a designated percent of the design target population using descriptive statistics. Application: The EBZ method can be utilized in the generation of humanoids for ergonomic design and evaluation of products when the large scale anthropometric database on the design target population is not existed.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.710-713
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• 2007

This paper presents the findings obtained from several series of analysis on the fatal accident, which are maintained by Korean Production Household Mascot Safety Industrial Complex, relative to fall. The fall accidents occurred in 5 years, from 2002 to 2006, were analyzed. The statistic relative to the fatal accidents analyzed according to different classifications such as accident rate, project amount, project type, cause, type of occupation. years of experience, and time in a day. This research would contribute to ensure the effectiveness of safety policy so as to enhance worker safety. In addition, cluster analysis was applied to find the major contributors on the fall accidents. Cross referencing between occupation and type of work, and occupation and cause were established so that the occurrence statistics of fall accidents were investigated.