• Journal of Preventive Medicine and Public Health
• /
• v.30 no.2 s.57
• /
• pp.356-368
• /
• 1997

In effort to determine whether aircraft noise can have health effects such as hearing loss, hypertension and psychological stress, a total of 111 male professors and administrative officers working a college near a military airport in Korea(exposed group) and a total of 168 males and 112 females matched by age groups(control groups) were analyzed. Personal noise exposure and indoor and outdoor sound level of jet aircraft noise were measured at the exposed are3. And pure tone, air conduction test and measurement of blood pressure were given to the exposed(males) and matched control groups (males and females). BEPSI(Brief Encounter Psychological Instrument) and psychological response to aircraft noise were examined for the exposed group. The noise dosimetry results revealed time-weighted averages(TWAs) that ranged from 61 to 68 dBA. However the levels encountered during taking off jet airplanes reached 126 dBA for two half minutes time period. Th, audiometric, test showed that mean values of HTL(hearing threshold level) in exposed group at every frequency(500, 1,000, 2,000, 4,000, and 8,000 Hz were much lower than them of male and female control groups. And in old age groups, interaction of age and noise was observed at 8,000 Hz in both ears(p<0.05). Conclusively, aircraft noise does not appear to induce hearing loss directly in high frequency, but may decreased hearing threshold level by interaction of aging process and noise exposure. However, difference of mean values of exposed and control groups on blood pressure was not significantly. In psychological test, annoyance was the most severe psychological response to noise in exposed group, but mean value of BEPSI was not correlated with job duration in exposed group.

• The Journal of Korean Academy of Prosthodontics
• /
• v.44 no.2
• /
• pp.229-242
• /
• 2006

Statement of problem: In order to increase preload with reducing the friction coefficient, abutment screws coated with pure gold and Teflon as dry lubricant coatings have been introduced. But the reported data indicate that if screw repeated tightening and loosening cycle, an efficiency of increasing preload was decreased by screw surface wearing off. Purpose: This study was to evaluate the influence of tungsten carbide/carbon coating, which has superior hardness and frictional wear resistance, on the preload of abutment screws and the stability of coating surface after repeated closures. Material and method: The rotational values of abutment screws and the compressive forces between abutment and fixture were measured in implant systems with three different joint connections, one external butt joint and two internal cones. Moreover the stability and the alteration of coating surface were examined by comparison of the compressive force and the removable torque values during 10 consecutive trials, observation with scanning electron microscope and analyzed the elemental composition with energy dispersive x-ray spectroscopy Results and conclusion: 1. Application of coating resulted in significant increase of compressive force in all implant systems(P<.05). The increasing rate of compressive force by coating in external butt joint was gloater than those in internal cones (P<.05). 2. Coated screw showed the significant additional rotation compared to non-coated screw in all implant systems (P<.05). There were no significant differences in the increasing rate of rotation among implant systems (P>.05). 3. Removable torque values were greater with non-coated screw than that with coated screw (P<.05). 4. Coated screw showed insignificant variations in the compressive forces during 10 consecutive trials(P>.05) 5. After repeated trials, the surface layer of coated screw was maintained relatively well. However surface wearing and irregular titanium fragments were found in non-coated screw.

• Journal of the Korean association of regional geographers
• /
• v.12 no.3
• /
• pp.364-381
• /
• 2006

Strategies for regional development has been implemented by facilitating the cultural industry since the mid 1990s. The government of Gyeongbuk attempted to establish the cluster of cultural industries and to enhance the capability of cultural industries. However, infrastructure of the industries is still weak. The most cultural industries are small-sized enterprises and are in low value-added production link in the value chain. This research examines the situation of cultural industries and then to recommend the direction of cluster of cultural industries in Gyeongbuk. The cluster of cultural industries in Gyeongbuk needs to be decentralized integration. Cultural industries in Gyeongbuk are found in dispersed regions with own cultural and industrial characteristics. The hub of cluster of cultural industries should be formulated to promote network among cultural industrial complexes in dispersed regions; thus, the hub is able to provide knowledge and information for the cultural industrial firms in Gyeongbuk. The supporting center as the hub of cluster has to input more energy to establish the on-line and off-line network among firms, and between firms and innovation agencies such as universities, cultural industrial organizations, and local governments. The cultural industrial cluster should be linked with IT cluster in Gumi and cluster of Daegu cultural industries to upgrade the value chain of cultural industries.

• Journal of Biosystems Engineering
• /
• v.41 no.4
• /
• pp.313-318
• /
• 2016

Purpose: This study measured and analyzed the PTO (power take off) torque of a transplanter according to the planting conditions during field operation. Methods: A torque measurement system was constructed with torque sensors to measure the torque of a PTO shaft, a measurement device to acquire sensor signals, and a power controller to provide power for a laptop computer. The field operation was conducted at four planting distances (26, 35, 43, and 80 cm) and two planting depths using the transplanter on a field with similar soil conditions. One-way ANOVA with planting distance and Duncan's multiple range test at a significance level of 0.05 were used to analyze the PTO torque. The torque ratio was calculated based on the minimum torque using the average PTO torque measured under each planting condition. Results: The average torques on the PTO shaft for planting distances of 26, 35, 43, and 80 cm at a low planting depth were 11.05, 9.07, 7.04, and 3.75 Nm, respectively; the same for planting distances of 26, 35, 43, and 80 cm at a middle planting depth were 12.20, 9.86, 7.94, and 4.32 Nm, respectively. When the planting distance decreased by 43, 35, and 26 cm, the torque ratio at a low planting depth increased by 88, 142, and 195%, respectively. When the planting distance decreased by 43, 35, and 26 cm, the torque ratio at the middle planting depth increased by 84, 128, and 182%, respectively. Conclusions: PTO torque fluctuated by planting distance and depth. Moreover, the PTO torque increased for short planting distances. Therefore, farmers should determine the planting conditions of the transplanter by considering the load and durability of the machine. The results of this study provide useful information pertaining to the optimum PTO design of the transplanter considering the field load.

• Korean Journal of Soil Science and Fertilizer
• /
• v.39 no.5
• /
• pp.285-291
• /
• 2006

The lysimeter ($1.2m\;with{\times}1.6m\;length$) experiment using $^{15}N$ tracer method was conducted to investigate the influence of slopes (degree 5, 15 and 30%) and fertilizer application methods (solid application and fertigation) on the behavior of applied urea in saprolite piled highland with Chinese cabbage cultivation. NDFFs(nitrogen derived from fertilizer) in soil were increased with decreasing of degree of slope and of depth of soil. The recovery as percentage of fertilizer nitrogen by Chinese cabbage were 69.5% for solid application and 76.5% for fertigation in 5% slope, 65.0% for solid application and 70.2% for fertigation in 15% slope, and 56.1% for solid application and 62.3% for fertigation in 30% slope. There, fertigation will make great contributions to the reduction of environmental contamination by run off and to the increase of fertilizer efficiency in Chinese cabbage cultivated highland.

• Journal of Life Science
• /
• v.15 no.6 s.73
• /
• pp.851-856
• /
• 2005

Although valuable microbes have been isolated from the soil for the various productions of useful components, the microbes which can be cultivated in the laboratory are only $0.1-1\%$ of all microbes. To solve this problem, the study has recently been tried for making the valuable components from the environment by directly separating unculturable micrbial DNA in the soil. But it is known that humic acid originated from the soil interrupts various restriction enzymes and molecular biological process. Thus, in order to prevent these problems, this study modified the method separated soil DNA with phenol, CTAB and PEG. In order to compare the degree of purity for each DNA and the molecular biological application process, $A_{260}/A_{280}$ ratio, restriction enzymes, and PCR were performed. In case of DNA by the modified method, total yield of DNA was lower but $A_{260}/A_{280}$ ratio was higher than the previously reported methods. It was confirmed that the degree of purity is improved by the modified method. But it was not cut off by all kinds of tested restriction enzymes because of the operation of a very small amount of interrupting substances. When PCR was operated with each diluted DNA in different concentrations and GAPDH primer, the DNA by the modified method could be processed for PCR in the concentration of 100 times higher than by the previously reported separation method. Therefore, this experiment can find out the possibility of utilization for the unknown substances by effectively removing the harmful materials including humic acid and help establishing metagenomic DNA library from the soil DNA having the high degree of purity.

• Journal of fish pathology
• /
• v.23 no.3
• /
• pp.281-291
• /
• 2010

Crytocaryon irritans infection of rock bream was investigated in embankment fish farm from July to December 2009. Prevalence variation was 20.0~88.0% that was high in september and was low in July. While no mortality was found in July and August, it occurred after mid september. Environmental conditions during the survey period were water temperature $19.3{\sim}24.3^{\circ}C$, dissolved oxygen $5.0{\sim}7.1\;mg\;L^{-1}$ and salinity 31.9~33.7 psu, and the water temperature during mortality season was $24.0^{\circ}C$. External symptom of the rock bream was secretion mucus but swimming showed fine in the early infected period. While, the symptoms in the severe outbreak season were excess of mucus, falling off tail and congestion, bleeding spot the surface and weakened swimming. We observed free living and parasitic stages in the gills and body surface of rock bream. Hepato somatic index (HSI) was $1.9{\pm}1.1{\sim}3.5{\pm}1.7%$, which was low in the September being mortality season but was high in November. The percentages of hematocrit infected with Crytocaryon irritans were 37.3% and 41.0% in July and August, respectively while they gradually decreased to 32.1% and 24.2% in september and October, respectively. Total cholesterol and Triglyceride values rapidly decreased by October. After mortality, AST and ALT were 7 and 5 folds higher compared to non-mortality season.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.9
• /
• pp.74-82
• /
• 2016

The term research institute spin-offs refers to new firms created by public research institutes. These spin-offs are different from other start-ups in two respects: on the one hand, they should be located in the Special Research and Development Zones and, on the other hand, these firms are supposed to commercialize the results of public R&D activities. These spin-off firms show higher rates of survival and job creation than general new firms, which means that their contribution to economic growth is not negligible. The present study analyzes the factors affecting research institute spin-offs using a random effect panel logit model and negative binomial model. From previous studies, four elements are identified as playing an important role in the commercialization of public R&D through spin-offs, namely their organizational character, research capability, technological character, and geographical location. The empirical results demonstrate that government research institutes with more researchers and patents are more likely to create new firms. In addition, the location of the institutes significantly affects the probability of their creating spin-offs and their number. When the technological stage and TLO size are considered, however, it turns out that the number of researchers and technological stage play important roles in the spin-offs.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.4
• /
• pp.438-443
• /
• 1999

Germination and growth of Laminaria japonica microscopic stages were investigated under crossed gradients of temperatures and irradiances, and the results related to the seasonal temperature regime in the southeastern coast of Korea. Germination rates of $70\~86\%$ were observed in the temperature range of $5\~20^{\circ}C$, however, at $25^{\circ}C$ no germination of meiospores was observed. The primary factor affecting germination rates at the temperature range of $5\~20^{\circ}C$ was irradiance: germination was significantly reduced at $150 {\mu}E{\cdot}m^{-2}{\cdot}s^{-1}$. Vegetative cell production of female gametophytes was highest at $20^{\circ}C$, but plants were not fertile at the temperature. In the temperature range of $5\~15^{\circ}C$, higher irradiance caused females to reduce cell production, but increased fertility. Cell production was also low at lower temperatures with increased fertility rates. Optimal growth temperature for microsporophytes was $10^{\circ}C$ and their growth rates were light-saturated at $70 {\mu}E{\cdot}m^{-2}{\cdot}s^{-1}$. We have concluded that meiospores released before July could develope to the young sporophytic stage in the southeastern coast of Korea which is off the southern limit of its geographical distribution. However, limiting factor in the development of natural sporophytic population in this region would be the upper temperature limit for the survival of young sporophytes, as water temperature at this area frequently exceeds $25^{\circ}C$ during the summer period.

• Cross-Cultural Studies
• /
• v.26
• /
• pp.123-144
• /
• 2012

In the modern society in which globalization and localization proceed simultaneously, diversified and rapid migration of diaspora makes a new from of boundary off the frame of the state and the nation. This new border accompanies cultural change and racial mixture; retains ethnic conflict, the gap between rich and poor, alienation and discrimination, as well as power conflict; and extends its influence. Nowadays, the countries all over the world including Korea face problem of Diaspora in numerous forms. And each country takes an approach to the problem of the diaspora in the aspects of their society, culture and political technology. This implies that most countries, without understanding the new form of border which is alive and dynamic, define and conceptualize the diaspora in the frame of one state and one nation to carry forward the policies accordingly, resulting in inequal, incomplete and awkward homogenization. This study aimed to explore the identity of the diaspora, the core for the problem solving. Of course, studies about the identity of the diaspora have been continued until today and many great outcomes have been achieved. Nevertheless, this study aimed to explore the identity of the diaspora and the national policies which have a close interrelationship with it. It is because the study ultimately aimed to highlight the interrelationship between the destination countries, Russia and China, and the diaspora, through the definition and the classification of Russian diaspora and Chinese diaspora and the analysis of the national policies about that. However, the intention was not to distinguish superiority through the comparison of the polices about the diaspora between two countries, but to focus on the diversity of the identity of the diaspora through defining each different diaspora and paralleling the policies. Second, the reason for looking into the diaspora policies of these two countries is because it is judged the changes in the diaspora policies of each country is one of the active factors for the changes in the identify of the diaspora of each country and it is the basic research for the study on the identity of the diaspora. New migration of diaspora changes the identity of the state, and the state makes the policies and enforce the policies, resulting in the influence on the diaspora. This interaction acts as the growth factor for the new boundary. The causes of Russian diaspora and Chinese diaspora show apparent 'differences'. In parallel with this, the policies about the diaspora in Russia and China arouse 'differences' to the diaspora. The variation of the identity of the diaspora made by these differences will suggest other viewpoints on the diaspora, and these viewpoints will become the foundation for solving the problem of the diaspora in the present times.