• Korean Journal of Agricultural Science
• /
• v.26 no.2
• /
• pp.77-93
• /
• 1999

This study is aiming at identifying the foreward and backward lingkage effects of the farm land base development project. Korean Government has continuously carried out farmland base development projets including the integrated agricultural development projects. large and medium scale irrigation projects and the comprehensive development of the four big river basin including tidal land reclamation and estuary dam construction for the all weather farming since 1962. the starting year of the five year economic development plans. Consequently the irrigation rate of paddy fields in Korea reached to 75% in 1998 and to escalate the irrigation rate, the Government had procured heavy investment fund from IBRD. IMF and OECF etc. To cope with the agricultural problems like trade liberalization in accordance with WTO policy, the government has tried to solve such problems as new farmland base development policy, preservation of the farmland and expansion of farmland to meet self-sufficiency of foods in the future. Especially, farmland base development projects have been challanged to environmental and ecological problems in evaluating economic benefits and costs where the value of non-market goods have not been included in those. Up to data, in evaluating benefits and costs of the projects, farmland base development projects have been confined to direct incremental value of farm products and it's related costs. Therefore the projects'efficiency as a decision making criteria has shown the low level of economic efficiencies. In estimating economic efficiencies including Leontiefs input-output analysis of the projects could not be founded in Korea at present. Accordingly this study is aimed at achieving and identifying the following objectives. (1) To identify the problems related to the financial supports of the Government in implementing the proposed projects. (2) To estimated backward and foreward linkage effects of the proposed project from the view point of national economy as a whole. To achieve the objectives, Hwangrak benefited area with reservoir which is located in Seosan-haemi Disticts, Chungnam Province were selected as a case study. The main results of the study are summarized as follows : a. The present value of investment and O & M cost were amounted to 3,510million won and the present value of the value added in related industries was estimated at 5.913million won for the period of economic life of 70 years. b. The total discounted value of farm products in the concerned industries derived by the project was estimated at 10,495million won and the foreward and backward linkage effects of the project were amounted to 6,760 and 5,126million won respectively. c. The total number of employment opportunities derived from the related industries for the period of project life were 3,136 man/year. d. Farmland base development projects were showed that the backward linkage effects estimated by index of the sensitivity dispersion were larger than the forward linkage effect estimated by index of the power of dispersion. On the other hand, the forward linkage effect of rice production value during project life was larger than the backward linkage effect e. The rate of creation of new job opportunity by means of implementing civil engineering works were shown high in itself rather than any other fields. and the linkage effects of production of the project investment were mainly derived from the metal and non-metal fields. f. According to the industrial linkage effect analysis, farmland base development projects were identified economically feasible from the view point of national economy as a whole even though the economic efficiencies of the project was outstandingly decreased owing to delaying construction period and increasing project costs.

• Polymer(Korea)
• /
• v.39 no.1
• /
• pp.88-98
• /
• 2015

4-Amino-N-hexadecylbenzamide-graphene sheets (AHB-GSs), used in the preparation of the polyimide (PI) nanocomposite films, were synthesized by mixing a dispersion of graphite oxide with a solution of the ammonium salt of AHB. The atomic force microscope image of functionalized-GS on mica and a profile plot revealed the average thickness of AHB-GS to be ~3.21 nm. PI films were synthesized by reacting 4,4'-biphthalic anhydride and bis(4-aminophenyl) sulfide. PI nanocomposite films containing various contents of AHB-GS over the range of 0-10 wt% were synthesized using the solution intercalation method. The PI nanocomposite films under different thermal imidization temperatures, 250 and $350^{\circ}C$, were examined. The graphenes, for the most part, were well dispersed in the polymer matrix despite some agglomeration. However, micrometer-scale particles were not detected. The average thickness of the particles was <10 nm, as revealed from the transmission electron microscope images. Only a small amount of AHB-GS was required to improve the gas barrier, and electrical conductivity. In contrast, the glass transition and initial decomposition temperatures of the PI hybrid films continued to decrease with increasing content of AHB-GS up to 10 wt%. In general, the properties of the PI hybrid films heat treated at $350^{\circ}C$ were better than those of films heat treated at $250^{\circ}C$.

• Korean Chemical Engineering Research
• /
• v.54 no.5
• /
• pp.612-620
• /
• 2016

Aqueous mineral carbonation process, in which $CO_2$ is captured through the reaction with aqueous calcium oxide (CaO) solution, is one of CCU technology enabling the stable sequestration of $CO_2$ as well as economic value creation from its products. In order to enhance the carbon capture efficiency, it is required to maximize the dissolution rate of solid reactants, CaO. For this purpose, the proper design of a reactor, which can achieve the uniform distribution of solid reactants throughout the whole reactor, is essential. In this paper, the effect of internal reactor designs on the solid dispersion quality is studied by using CFD (computational fluid dynamics) techniques for the pilot-scale reactor which can handle 40 ton of $CO_2$ per day. Various combination cases consisting of different internal design variables, such as types, numbers, diameters, clearances and speed of impellers and length and width of baffles are analyzed for the stirred tank reactor with a fixed tank geometry. By conducting sensitivity analysis, we could distinguish critical variables and their impacts on solid distribution. At the same time, the reactor design which can produce solid distribution profile with a standard deviation value of 0.001 is proposed.

• Journal of Life Science
• /
• v.28 no.3
• /
• pp.284-292
• /
• 2018

The melanin-concentrating hormone (MCH), a cyclic hypothalamic peptide composed of 17 amino acids, was initially identified in chum salmon (Oncorhynchus keta) as a regulator of pigmentation. Mammalian MCHs are cyclic hypothalamic peptides composed of 19 amino acids that regulate food intake and energy homeostasis. The present study examined not only MCH expression of different tissues but also the melanohore aggregation and intracellular $Ca^{2+}$ influx of fMCH and the other MCH. Real-time qPCR showed that MCH expressed specially in the brain, gonad, and ovary, and expression of MCH was observed during the developmental stages. In the application of synthetic fMCH and both types of synthetic fMCH, dN-fMCH and dC-fMCH, scale melanophore induced significant changes in aggregation activity with various concentrations of MCH. Also, compared to hMCH and sMCH, fMCH exhibited a 36~99.85% increase in relative potency (%), whereas aggregation of dN-fMCH and dC-fMCH remained in a high concentration. However, dispersion was induced rapidly according to be low concentration of dN-fMCH and dC-fMCH. We show that fMCH and its derivates were bound human MCHR1 and rat MCHR expressed in HEK293T cells with nano-molar affinity and are likely to be ligand-induced to mobilize intracellular $Ca^{2+}$. These results may provide new ligands for binding assay with MCHew ligands, as a structure similar to the mammalian MCH structure was discovered in fish. Once the fMCH receptor system is in place, it can be compared to the MCH system of mammals in terms of MCH function.

• Journal of the Economic Geographical Society of Korea
• /
• v.18 no.3
• /
• pp.267-280
• /
• 2015

The European civil aviation industry, which had lower technical skills, capital strength and market scale than the U.S., adopted the production system of joint development and division labor between the nations of Europe. Each plant locations strengthened their specialization of the production branch in the past 40 years with a geographical accumulation of the specialized manufacturing facilities, suppliers, universities and laboratories by the logic of geographical proximity and learning effect. The cargo plane transportation system in the production of short- and medium-haul aircraft facilitated the geographical dispersion of manufacturing process and the logistical linkage among the various plant locations. But the production of long-haul large aircraft(A380) chosen the transportation system by the cargo ship because of the size and weight. Considering the transportation system by the cargo ship, the choice of Toulouse as a final assembly plant location was the irrational locational decision from a locational point of view. This locational choice is explained by the merging process of the European civil aviation industry, the logic of learning effect and geographical proximity, and the active attraction support policy.

• Journal of the Korean Society of School Health
• /
• v.23 no.1
• /
• pp.63-70
• /
• 2010

Purpose: To identify the need to reform in the crisis response of Health Teacher, School Nurse, in elementary school during epidemic outbreak of influenza H1N1. Methods: 139 elementary health teachers, school nurse, in seoul elementary school responded in the questionnaire, and we analysed by using frequency and percent, t-test, and paired t-test. Results: The Job status became 121% more 'during influenza H1N1 (flu) outbreak' than Job status of 'before outbreak'. The proportion of the flu-related duty among their daily workload was up to 77.5%. The administration-related workload of the flu-related duty was 30.8%. and students' health assessment including temperature measurement 18.7%. Furthermore, an impediment of usual daily work due to an increaed flu-related workload was 95.7%, and no alternative plan such as disposition of assistant labor force was 86.1%. Especially, an impediment of health education was 61.0%, so the major concern was the loss of health education. We compared average scores (a five-point Likert scale) of health teachers' work motivation, exhaustion, work relationship and Job management of 'during' with 'before' flu-outbreak. The difference range of 'during' minus 'before' work motivation score was from -0.4 points to -0.9; work exhaustion range from 1.8 to 1.9; the difficulty of relationship between students, school personnel, parents of students, and health teachers from 1.4 points to 1.3 points; and the consideration of changing Job, taking time off from the Job and retirement from 1.4 to 1.6 points. Conclusion: The health teachers had a heavy workload due to flu-outbreak. They also experienced the impediment of usual work implementation. However, there was a shortage of alternative plan such as disposition of an assistant labor force. Under their Job status like this, the health teachers' motivation score was decreased and work exhaustion was increased. Furthermore, they had a lot of relation difficulty with students and school personnel. Therefore, we suggested that in contrast to the usual Job status, there is a need to have a prepared response during school crisis like flu-outbreak such as improved response system in seoul metropolitan education office, simplification or dispersion of administrative work, and temporary call-center for simple inquiries or advices.

• Resources Recycling
• /
• v.23 no.6
• /
• pp.22-29
• /
• 2014

Recycling process of iron should be developed for efficient recovery of neodymium (Nd), rare metal, from acid-leaching solution of Nd magnet. In this study, $FeCl_3$ solution as iron source was used for preparation of iron nano particles with the condition of various factors, such as, reductant, and surfactant. $Na_4P_2O_7$ and Polyvinylpyrrolidone (PVP) as surfactants, $NaBH_4$ as reductant, and palladium chloride ($PdCl_2$) as a nucleation seed were used. Iron powder was analyzed by using XRD, SEM for measuring shape and size. Iron nano particles were prepared at the ratio of 1:5 (Fe (III) : $NaBH_4$). Size and shape of iron particles were round-form and 50 ~ 100 nm size. Zeta-potential of iron at the 100 mg/L of $Na_4P_2O_7$ was negative value, which was good for dispersion of metal particle. When $Na_4P_2O_7$ (100 mg/L), PVP($FeCl_3:PVP$ = 1 : 4, w/w) and Pd($FeCl_3:PdCl_2$ = 1 : 0.001, w/w) were used, iron nano particles which were round-shape, well-dispersed and near 100 nm-sized range. In this condition, $FeCl_3$ solution changed with spent Nd leachate solution, and then it is possible to be made round-formed iron nano particles at pH 9 and at the reaction bath over 20 L which is not include any surfactant.

• Journal of the Economic Geographical Society of Korea
• /
• v.1 no.2
• /
• pp.85-102
• /
• 1998

The Changing Characteristics of Office Location in Central Seoul In recent years, central Seoul has been experiencing a dynamic transformation. In the process of reorganization of urban industrial structure including tertiarization and quaternarization of the economic base of Seoul, business services are growing very rapidly and large scale urban renewal projects are agilely implemented. Downtown office activities become a nucleus for economic performance of Seoul and high-rise office buildings steer the landscape transformation of central Seoul. Even though there appear to exist some evidences that office districts have dispersed to several subcenters, major office activities are still concentrated in the central Seoul. This paper redefines office industry in a narrow meaning comprising only relevant economic sectors and office buildings as office activity-functioning units. It then explores the industrial networking and territorial specialization of office activities focusing on the dual process of concentration and dispersion in Seoul. The changing characteristics of the downtown linkages of office activities in this post-industrial era transforms the spatial economy of central Seoul into more flexible and volatile, while territorial concentration of power and control functions are fortified at the same time. Finally, the paper addresses the development of manufacturing-tertiary-quaternary industrial complex, which can be regarded as new industrial clusters, selling cultural economy of urban space and possessing placeness or images for clients and customers, in relation to urban competitiveness and territorial specialization of large metropolitan areas.

• Journal of Korean Society of Transportation
• /
• v.29 no.2
• /
• pp.91-100
• /
• 2011

Hub network design for freight transportation is a decision process that determines hub locations together with freight transportation routes among shippers so as to ultimately minimize total logistics cost. This study presents the optimal location of hubs by strict hub network design policy with single allocation, which overcomes the limitation of Kim et al. (2008) that does not allow direct transportation among shippers. The greedy-interchange algorithm is employed for hub location decision process, and EMME/2 is adopted for the route searching process. Application of the processes to the nationwide highway network shows that the best hub locations in order are Seoul metropolitan, GyeongNam, Chung-nam, Jeon-Nam, Gyeong-Buk, Chung-Buk, and the locations are concentrated on the Seoul-Busan corridor. The strict hubnetwork design policy with single allocation increases the transportation distance but decreases the transportation cost by passing through the hubs instead of direct transportation. The reduction in total transportation cost can be achieved as the number of hubs increases, but the amount of the reduction gradually decreases because the cost reduction from the decrease in detour transportation distance between non-hubs and hubs becomes less than the discount reduction from dispersion of inter-hubs transportation volumes.

• Membrane Journal
• /
• v.27 no.2
• /
• pp.154-166
• /
• 2017

Polymeric films for gas barrier applications such as food packaging and electronic devices have attracted great interest due to their cheap, light and easy processability among gas barrier materials. Especially in electronic devices, extremely low gas permeance is necessary for maintaining the device performance. However, current polymeric barrier films still suffer from relatively high gas permeance than other materials. Therefore, there have been strong needs to enhance the gas barrier performance of polymeric barrier films while keep their own advantages. Recently, graphene is highlighted as a 2D-layered material for gas barrier applications. However, owing to the poor workability and difficulty to produce in engineering scale, graphene oxide (GO) is on the rise. GO consists of oxygen-containing functional groups on surface with intrinsic 2D-layered structure and high aspect ratio, and it can be well-dispersed in aqueous polar solvents like water, resulting in scalable mass production. Here, we prepared GO incorporated polyimide (PI) nanocomposites. PI is widely used barrier polymer with high mechanical strength and thermal and chemical stability. We demonstrated that PI/GO nanocomposites could perform as a gas barrier. Furthermore, surfactants (Triton X-100 (TX) and Sodium deoxycholate (SDC)) are introduced to enhance the gas barrier performance by improving the degree of dispersion of GO in PI matrix. As a result, TX enhanced the gas barrier performance of PI/GO nanocomposites which is similar to predicted value. This finding will provide new insight to polymer nanocomposites for gas barrier applications.