• Journal of the Korean Society of Combustion
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• v.2 no.1
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• pp.17-27
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• 1997

It is well known that NOx formation has a strong dependence on the maximum temperature and correspondingly with the maximum chamber pressure of a closed combustion system. However, in a case of impinging-jet-flame (IJF hereafter) combustion with opposed dual pre-chambers, low $NO_x$ formation with high pressure could be achieved, but its mechanism has not been clearly understood so far. In this study, a three-dimensional analysis is adopted to resolve time-variant local properties that might indicate the mechanism of IJF combustion. Numerical results are verified by comparing them with experiments. The IJF combustion in a vessel with no pre-chamber, with single pre-chamber, and with dual pre-chambers is studied. The orifice diameter and the volumetric ratio of pre-chamber are used as geometric parameters. The effects of main-chamber ignition delay time and combustion time of main-chamber, orifice exit velocity, orifice exit temperature, turbulent kinetic energy of main-chamber and spatial distribution of temperature in the latter stage of combustion are investigated. A longer main-chamber ignition delay and a shorter main-chamber combustion time suppress the formation of high temperature region with respect to mean temperature, which consequently results in less NO production.

• Journal of Animal Reproduction and Biotechnology
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• v.35 no.3
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• pp.279-288
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• 2020

Changes of gonadal morphology and mRNA expression patterns of vitellogenin were investigated in Siberian sturgeon Acipenser baerii (Chondrostei) during its early gonadal maturation period. Early differentiations and morphological transitions of both ovaries and testes appeared to occur actively until the age of 3 years, however from then on, the maturation patterns to full maturity were largely gender-dependent, in which males showed a faster progression of maturation than did females while females experienced a steady-state progress with a lagged interval before entering the final maturation. Expression of vitellogenin mRNAs are closely correlated with transitional patterns of gonadal appearances. In both females and males, hepatic mRNA levels of vitellogenin exponentially increased in the earliest interval (up to 1-year-old). However, in subsequent periods, vitellogenin expression in females continued to increase with age, whereas in males, the expression stabilized at a younger age. Nevertheless, at the age older than or equal to 7-year-old, fully matured individuals showed a quite low level of vitellogenin expression in both females and males. Collectively, results from this study could be useful as a fundamental guideline to address the gonad maturation of this sturgeon species, which is helpful for making practical decisions about farming practices and management for caviar production on local sturgeon farms.

• Journal of Korean Society of Rural Planning
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• v.21 no.3
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• pp.131-144
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• 2015

With a view to creating beautiful farm villages, this study aims to exploit space syntax and thereby establish a systematic plan for refurbishing common farming facilities in farm villages by expanding a remodeling plan that has so far been focused on farm houses to cover different villages as well as in spatial scope. For this purpose, the study has extracted a system of categories for common ownership facilities in farm villages and applicable elements needed for collaboration in the space of joint production by performing a comprehensive analysis of related literature for the purpose of researching the distribution of common farming facilities. Based on such categorization of applicable elements, the study conducted a field survey of the four types of farm villages such as suburban area (Hwaseong), inland farming-centered area (Jeungpyeong), coastal & plain area (Goheung), and mid-mountain area (Gangneung), through group discussions by participating researchers and field pilot surveys. Also, space analysis has come up with measurements based on the five criteria of integration, local integration, control, connectivity, and spatial depth. And a plan for type-specific remodelling of common farming facilities has been drawn up through standardization based on the values in integration for different villages and spatial depth for common farming facilities. The significance of the current study consists in identifying how the location of common farming facilities influences the characteristics of different villages in terms of spatial structure and then drawing up guidelines for planning their placement.

• Journal of the Korea Convergence Society
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• v.8 no.11
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• pp.257-262
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• 2017

The success or failure of the Korean game industry is a key issue for the creation of competent and talented human resources for the production of competent contents. The purpose of this study is to elucidate how to characterize and educate human - friendly game graphic designers with global competitiveness. The success of multi-disciplinary education will be maximized when cooperation with the responsible professors, the active will of the professor, the educational vision of the school, and real-time and active administration are supported In this study, based on the analysis of demand and supply of the human resources in the game industry, we found out that the game industry requires specialized manpower of technology-friendly game graphic designer who has the creativity, practical. application ability, and the international competency. In addition, we suggested ways of linking the curriculum with the local industries and related organizations such that they could be well educated as experts in related fields.

• The Journal of the Korean dental association
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• v.48 no.12
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• pp.893-918
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• 2010

This article is purposed of reviewing the development history of Japanese dental devices and instrument, and their related advertisement activities during the Japanese colonized period in Korea in early 20th century. Japanese dental devices and instrument were redesigned to accommodate their ergonomic shape above the simple imitation, and it implies the excessive desires brought them frustrations. The tragic earthquake on Sep. l, 1923, medical insurance law enforcement on Jan. 1, 1927, celebration of "Cavity prevention Day" started on Jun. 4, 1928, and the attack of Manchuria and China by Japan after 1931, all of these historical incidents become the preliminary requirement for the development of dental devices. On Nov. 1, 1937, Japanese government started to control dental materials, driving the campaigns for excluding foreign products and encourging the use of local products. In 1939, Nakajima dental manufacturers used this political and social atmosphere on their advertisement as saying "Our Nakajima's products have no compromise with the short raw materials, but only commitment to our quality". Since after 1940, the price and supply have been strongly under control, and the control group was appeared to manage all of supply and distribution of raw materials, regular price system, and specifications. At last, the Japanese national power were devastated in its production and distribution capacities, and get to the frustrated period. The main advertised dental devices and instruments in Korea during the Japanese colonized period were 1) dental chair, unit and cabinet, 2) dental x-ray, 3) compressors, 4) dental needles, 5) small instrument and carryon medical(emergency) kit, 6) oral hygiene and pyorrhea alveolaris, infrared rays, sunlight lamp, ultrashort wave treatment devices, 7)crown former, electric furnace, casting machine, articulator, electric lathe, and laboratory equipments, etc.

• Korean Journal of Organic Agriculture
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• v.11 no.2
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• pp.23-42
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• 2003

The study must have standpoints for the stable market construction of the Environmental-Friendly agricultural products of the quality-certificated which has rapidly grown due to a discussion of the environment and agriculture, income increase and the interests on foods stability. The survey was conducted through face-to-face interview of 200 adults who are in their twenties or more in Cheonan-city. In this research, the Environmental-Friendly agriculture was a clean agriculture not using a fertilizer or chemicals and the agriculture which protects the environment by preventing the environmental pollution. In the analyses of the consumer's willingness to pay, the rice showed 69,851 won, and a lettuce and bean-curd showed 947 won and 1.412 won respectively. In terms of current issues of the policy, to establish the stable circulation structure and consumption strategy, there must be a clearness raise of the Quality Authentication (QA) Mark. To raise the trust through quality authentication, there must be transparency raise of information by distribution stages and the thorough post management of the official institutes. Also, to persue the competitive product differentiation, there must be the settlement of the product brand on the market, development of the new production technology and a classification of consumers by incomes. Finally to construct stable distribution and price system, there must be active participation of the local agricultural cooperatives in the distribution of the Environmental-Friendly agricultural products of the quality-certificated and the understanding of the proper price of the consumer market and flexible strategy of the price change.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.3
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• pp.617-622
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• 2006

In the present study, we investigated the anticariogenic compounds from Aralia continertalis (A. continnentalis) has been isolated and identified by MS, $^1H-NMR$ and $^{13}C-NMR$. The MeOH extract was suspended in $H_2O$ and sequentially Partitioned with $CHCl_3$, EtOAc, and n-BuOH. The $CHCl_3$ fraction showed remarkable antibacterial activity against S. mutans. The antibacterial activity compounds against 5. mutans by MIC was isolated successively through the screening system and various chromatography methods. From this active chloroform subfraction, isolation and identification finally gave continentalic acid by spectroscopic methods (MS, $^1H-NMR$ and $^{13}C-NMR$) as an active principle. The compound, continentalic acid, showed significant growth, acid production, adhesion and water-insoluble glucan synthesis inhibitory effect against 5. mutars. These results suggest that continentalic acid from A. continentalis may inhibit cariogenic properties of S. mutans and these properties may provide some scientific rationales that the local inhabitants used the extracts for treatment of dental diseases.

• Korean Journal of Remote Sensing
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• v.32 no.1
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• pp.1-11
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• 2016

Since forest is an important part of ecological system, the deforestation is one of global substantive issues. It is generally accepted that the climate change is related to the deforestation. The issue is worse in developing countries because the forest is one of important natural resources. In the case of North Korea, the deforestation is on the rise from forest reclamation for firewood collection and food production. Moreover, a secondary effect from flood intensifies the damage. Also, the political situation in North Korea presents difficulty to have in-situ measurements. It means that the accurate information of North Korea is nearly impossible to obtain. Thus, assessing the current situation of the forest in North Korea by indirect method is required. The objective of this study is to monitor the forest status of North Korea using multitemporal Landsat images, from 1980s to 2010s. Since the deforestation in North Korea is caused by local residents, we selected two study areas of high population density: Pyeongyang and Hyesan. In North Korea, most of clean Landsat images are acquired in fall season. The fall images have an advantage that we can easily distinguish agriculture areas from forest areas, also have an disadvantage that the forests cannot be easily identified because some of trees have turned red. To identify the forests exactly, we proposed a modified Normalized Difference Vegetation Index (mNDVI) value. The deforestation in Pyeongyang and Hyesan was analyzed by using mNDVI. The dimension of forest has decreased approximately 36% in Pyeongyang for 27 years and approximately 25% in Hyesan for 16 years. The results show that the forest areas in Pyeongyang and Hyesan have been steadily reduced.

• Journal of Veterinary Clinics
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• v.34 no.2
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• pp.146-151
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• 2017

Six major outbreaks of highly pathogenic avian influenza (HPAI) occurred from 2003 to 2016 in Korea. Epidemiological investigations of each outbreak revealed that migratory birds were the primary source of the HPAI virus. During the last five years, the geographic transmission pattern of domestic HPAI seems to have extended from local to nationwide; therefore, it is necessary to identify specific locations in which poultry farms are at elevated risk for HPAI outbreak to enable targeted surveillance and other mitigation strategies. Here, a geographical information system (GIS)-based analysis was used to identify geographic areas at high risk for future HPAI incidents in Korea based on historical outbreak data collected between December 2003 and April 2016. To accomplish this, seven criteria were used to identify areas at high-risk for HPAI occurrence. The first three criteria were based on defined spatial criteria buffering of 200 bird migration sites to some defined extents and the historical incidence of HPAI outbreaks at the buffering sites. The remaining criteria were based on combined attribute information such as number of birds or farms at district levels. Based on the criteria established for this study, the most-likely areas at higher risk for HPAI outbreak were located in Chungcheong, Jeolla, Gyeonggi, and Gyeongnam provinces, which are densely populated poultry regions considered major poultry-production areas that are located along bird migration sites. The proportion of areas at risk for HPAI occurrence ranged from 4.5% to 64.9%. For the worst criteria, all nine provinces, including Jeju Island, were found to be at risk of HPAI. The results of this study indicate that the number of poultry farms at risk for HPAI outbreaks is largely underestimated by current regulatory risk assessment procedures conducted for biosecurity authorization. The HPAI risk map generated in this study will enable easy use of information by policy makers to identify surveillance zones and employ targeted surveillance to reduce the impact of HPAI transmission.

• Journal of agriculture & life science
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• v.44 no.6
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• pp.213-222
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• 2010

The purpose of this study is to detect challenges and matters for improvement, an recent emerging export market with high potential for Korean agricultural products, and to finally find out measures to increase agricultural export to the market. In order to expand the export of agricultural products to Russian Far East, first of all, Competitiveness in terms of quality and price could be enhanced by improving production facilities, developing new technologies and improving logistical system. Secondly, the export volume should be secured in a stable manner, and it can be achieved by systematically running a larger export organization and unifying contact points. Thirdly, the screening, transportation and storage of agricultural products at low temperature should be offered at the local transportation and distribution stage. Fourthly, the consumers of Russian Far East have very little knowledge of the Korean agricultural products. To overcome this, more active PR, promotional and marketing activities are required.