• Journal of Bio-Environment Control
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• v.31 no.2
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• pp.79-89
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• 2022

With the wide use of greenhouses, the working hours have been increasing inside the greenhouse for workers. In the closed ventilated greenhouse, the internal environment has less affected to external weather during making a suitable temperature for crop growth. Greenhouse workers are exposed to organic dust including soil dust, pollen, pesticide residues, microorganisms during tillage process, soil grading, fertilizing, and harvesting operations. Therefore, the health status and working environment exposed to workers should be considered inside the greenhouse. It is necessary to secure basic data on particulate matter (PM) concentrations in order to set up dust reduction and health safety plans. To understand the PM concentration of working environment in greenhouse, the PM concnentrations were monitored in the cut-rose and Hallabong greenhouses in terms of PM size, working type, and working period. Compare to no-work (move) period, a significant increase in PM concentration was found during tillage operation in Hallabong greenhouse by 4.94 times on TSP (total suspended particle), 2.71 times on PM-10 (particle size of 10 ㎛ or larger), and 1.53 times on PM-2.5, respectively. During pruning operation in cut-rose greenhouse, TSP concentration was 7.4 times higher and PM-10 concentration was 3.2 times higher than during no-work period. As a result of analysis of PM contribution ratio by particle sizes, it was shown that PM-10 constitute the largest percentage. There was a significant difference in the PM concentration between work and no-work periods, and the concentration of PM during work was significant higher (p < 0.001). It was found that workers were generally exposed to a high level of dust concentration from 2.5 ㎛ to 35.15 ㎛ during tillage operation.

• Journal of Life Science
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• v.32 no.2
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• pp.108-118
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• 2022

The subventricular zone (SVZ) in the brain contains neural stem cells (NSCs) that generate new neurons throughout one's lifetime. Many extracellular and intracellular factors that affect cell proliferation and neuronal differentiation of NSCs are already well-known. Recently, L-type calcium channels have been reported to regulate neural development and are present in NSCs, differentiating neuroblasts, and mature neurons in the SVZ. Nifedipine, a blocker of L-type calcium channels, has been long used as a therapeutic drug for hypertension. However, studies on the use of nifedipine to inhibit L-type calcium channels of NSCs are lacking. Herein, we treated NSCs cultured from mouse postnatal SVZ with nifedipine during neuronal differentiation. Nifedipine increased the number of Tuj1-positive neurons but did not significantly change the number of Olig2-positive oligodendrocytes. Nifedipine increased cell division during early differentiation, which was detected using the 5-ethynyl-2'-deoxyuridine incorporation assay and immunocytochemistry assessment by staining the cells with phosphorylated histone H3, a mitosis marker. Nifedipine increased the transcription of Dlx2, a neurogenic transcription factor, and the level of Mash1, a marker for early neurogenesis. In addition to nifedipine, verapamil, which is also an L-type calcium channel blocker, showed a slight increase in neurogenesis, but its statistical significance was very low. In contrast, pimozide, a T-type calcium channel blocker, did not affect neurogenesis, although T-type calcium channel genes Cav3.1, Cav3.2, and Cav3.3 were expressed. In summary, nifedipine might promote the neuronal fate of NSCs during early differentiation and calcium signaling through L-type calcium channels might be involved in neuronal differentiation, especially during the early stages of differentiation.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.41 no.4
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• pp.8-20
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• 2023

Although the landscape architectural facilities need to be repaired according to historical and authentic techniques, the repair criteria of the standard specification for repairing cultural heritages still remain at a theoretical level, and there are little research analyzing detailed techniques from specific cases. This study discussed the repair techniques based on historical facts, around terraced flower beds, ponds, waterways and pavement in the government-managed spaces in the Joseon Dynasty. It analyzed the materials and finish of stone wall elements, the structural reinforcement and backfill materials, and topsoil surface protection measures, and drew out stones for foundation reinforcement, plastering material for agglutination, and stone processing techniques for the terraced flower beds. It examined the materials and structures of the rock revetment, foundation reinforcement and waterproofing techniques and drew out the outstanding characteristics of the foundation work, the recycle of used elements and the management of water quality, for the ponds. It primarily investigated the materials, foundation reinforcement and waterproofing techniques and discovered the repair techniques such as cover stone finishing methods, foundation and backfill materials, and flow reduction methods, for the waterways. Finally, it provided actual cases of the foundation composition, auxiliary materials and tools, and the use of cyperaceae and highlighted the existence of professional craftsmen called Bangjeonjang(方磚匠), for the pavement. This study is expected to be a staring point for discovering the repair techniques for landscape architectural facilities and used as basic data for revising specifications in the future.

• Journal of the Korean Recycled Construction Resources Institute
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• v.12 no.1
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• pp.8-16
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• 2024

Limestone (CaCO₃, calcium carbonate), which is used as a raw material in the portland cement and steel industry, emits CO₂ through decarbonation by high temperatures in the manufacturing process. To reduce CO₂ emissions by the use of raw materials like limestone, it has been proposed to replace limestone with various industrial by-products that contain CaO but less or none of the carbonated minerals, that cause CO₂ emissions. Loss of Ignition (LOI), Thermogravimetric analysis (TG), and Infrared Spectroscopy (IR) are used to quantitative the amount of CO₂ emission by using these industrial by-products, but CO₂ emissions can be either over or underestimated depending on the characteristics of by-product materials. In this study, we estimated CO₂ contents by LOI, TG, IR and DTG(Differential Thermogravimetric analysis) of calcite(CaCO₃) and samples that contain CO₂ in the form of carbonate and whose weight increases by oxidation at high temperatures. The test results showed for CaCO₃ samples, all test methods have a sufficient level of reliability. On the other hand, for the CO₂ content of the sample whose weight increases at high temperature, LOI and TG did not properly estimate the CO₂ content of the sample, and IR tended to overestimate compared to the predicted value, but the estimated result by DTG was close to the predicted valu e. From these resu lts, in the case of samples that contain less than a few percent of CO₂ and whose weight increases during the temperature that carbonate minerals decompose, estimating the CO₂ content using DTG is a more reasonable way than LOI, TG, and IR.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.19 no.4
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• pp.231-241
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• 2024

Discovering innovative startups that use public technologies from universities and government-funded research institutes is crucial for maintaining national competitiveness. Advancing public R&D technology, discovering entrepreneurs from research institutes, and fostering and investing in deep-tech startups are very important at the national level. However, there is a lack of research on activating startups using public technologies, and research analyzing each governance entity is needed to activate the innovation startup ecosystem. Therefore, this study conducted an empirical analysis of the priorities for revitalizing the innovation startup ecosystem among researchers, research institutes, innovative startups, and the government, which constitute the public technology governance. The results of this study revealed that the sustainability of innovative startups (0.308), government innovation startup activation (0.298), research institutions discovering and fostering startups (0.221), and researcher's characteristics (0.173) were the most significant factors in the public R&D technology innovation startup ecosystem. And the sub-factors of researcher's characteristics, seizing business opportunities (0.305) was most important, and creating a startup-friendly culture (0.293) was most important among the sub-factors of research institutions discovering and fostering startups. Investment funds and procurement (0.373) was the most critical sub-factor for the sustainability of innovative startups, while a dedicated fund for public technology (0.305) was the most important among the sub-factors of government schemes for promoting innovative startups. A total of 20 factors were analyzed sequentially according to their importance in the weights for evaluation factors and sub-factors. By sub-factor, investment and financing for innovative startups (0.115), dedicated government fund for public technology (0.091), securing high-quality human resources for innovative startups (0.078), improving government regulations and permits related to innovative technologies (0.074), and creating a startup-friendly culture in research institutions (0.065) were the most important. This result emphasizes the significance of securing competitiveness to become a sustainable public technology startup. In addition, based on entrepreneurship experience, 'dedicated funding for public technology' was most important for the group with startup experience, while the group with no experience needed more 'investment and funding'. Furthermore, By region, 'improving government regulations and permits' was the highest priority in the Seoul metropolitan area, while 'attracting investment and financing' was the most important in Daejeon. Therefore, the results of this research, it is important to give policy priority to innovative startup companies in order to activate the innovation startup ecosystem in the public technology sector. The political and practical implications were derived that long-term (10 years or more) investment and funding for deep tech companies and the establishment of public technology-only funds are the most urgent and important.

• Journal of dental hygiene science
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• v.6 no.3
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• pp.147-152
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• 2006

The purpose of this study was to help decrease turnover and to make full use of dental hygienists and to help improve management by managers. After relevant literature and data were reviewed, a survey was conducted on dental hygienists, who worked at dental institutes in different areas, for about four months from September through December, 2004, to find out their turnover intention and job satisfaction level. When the collected data were analyzed, the following findings were given: 1. The collective average of the dental hygienists investigated in job satisfaction was $3.30{\pm}0.70$. By area, they expressed the best satisfaction at a clear role factors with a mean of $3.53{\pm}0.73$, and they were pleased with wages factors and promotion factors the least with an average of $3.14{\pm}0.70$ and $3.18{\pm}0.80$. 2. The collective average of the dental hygienists investigated in turnover intention was $3.23{\pm}0.77$. As for connections between general characteristics and turnover intention, By age, those who aged in 21 and 25 were most intended(p < 0.001). The unmarried dental hygienists were more intended than the married ones(p < 0.001). By type of hospital, those who worked at dental clinics were most intended(p< 0.01). By career, those who had worked at one to three years were intended the most(p < 0.001), and as to the length of service at current work places, those who had worked at their current work places for one to three years were intended the most(p < 0.001). By monthly mean pay, those whose pay ranged from 1.3 to 1.6 million won found their turnover most intended(p< 0.01). 3. Regarding correlation among turnover intention and job satisfaction were both inversed correlationship, and wages factor(r = -0.249, p < 0.01) and interrelationship factors(r = -0.218, p < 0.01) had a strong correlation to turnover intention, and clear role factors had a strong correlation to job contents factors by job satisfaction(r = 0.612, p < 0.01), and job satisfaction factors had a strong correlation to job contents factors(r = 0.759, p < 0.01).

• Journal of the Korean earth science society
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• v.38 no.4
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• pp.283-292
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• 2017

In this study, the empirical models were established to estimate the concentrations of surface-level $PM_{2.5}$ over Seoul, Korea from 1 January 2012 to 31 December 2013. We used six different multiple linear regression models with aerosol optical thickness (AOT), ${\AA}ngstr{\ddot{o}}m$ exponents (AE) data from Moderate Resolution Imaging Spectroradiometer (MODIS) aboard Terra and Aqua satellites, meteorological data, and planetary boundary layer depth (PBLD) data. The results showed that $M_6$ was the best empirical model and AOT, AE, relative humidity (RH), wind speed, wind direction, PBLD, and air temperature data were used as input data. Statistical analysis showed that the result between the observed $PM_{2.5}$ and the estimated $PM_{2.5}$ concentrations using $M_6$ model were correlations (R=0.62) and root square mean error ($RMSE=10.70{\mu}gm^{-3}$). In addition, our study show that the relation strongly depends on the seasons due to seasonal observation characteristics of AOT, with a relatively better correlation in spring (R=0.66) and autumntime (R=0.75) than summer and wintertime (R was about 0.38 and 0.56). These results were due to cloud contamination of summertime and the influence of snow/ice surface of wintertime, compared with those of other seasons. Therefore, the empirical multiple linear regression model used in this study showed that the AOT data retrieved from the satellite was important a dominant variable and we will need to use additional weather variables to improve the results of $PM_{2.5}$. Also, the result calculated for $PM_{2.5}$ using empirical multi linear regression model will be useful as a method to enable monitoring of atmospheric environment from satellite and ground meteorological data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.262-268
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• 2017

The energy consumption of buildings is approximately 20.5% of the total energy consumption, and the interest in energy efficiency and low consumption of the building is increasing. Several studies have performed energy analysis and evaluation. Energy analysis and evaluation are effective when applied in the initial design phase. In the initial design phase, however, the energy performance is evaluated using general level information, such as glazing area and surface area. Therefore, the evaluation results of the detailed design stage, which is based on the drawings, including detailed information of the materials and facilities, will be different. Thus far, most studies have reported the analysis and evaluation at the detailed design stage, where detailed information about the materials installed in the building becomes clear. Therefore, it is possible to improve the accuracy of the energy environment analysis if the energy environment information generated during the life cycle of the building can be established and accurate information can be provided in the analysis at the initial design stage using a probability / statistical method. On the other hand, historical data on energy use has not been established in Korea. Therefore, this study performed energy environment analysis to construct the energy environment historical data. As a result of the research, information classification system, information model, and service model for acquiring and providing energy environment information that can be used for building lifecycle information of buildings are presented and used as the basic data. The results can be utilized in the historical data management system so that the reliability of analysis can be improved by supplementing the input information at the initial design stage. If the historical data is stacked, it can be used as learning data in methods, such as probability / statistics or artificial intelligence for energy environment analysis in the initial design stage.

• Korean Journal of Plant Resources
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• v.27 no.5
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• pp.556-566
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• 2014

In this study, we collected 29 Kenaf (Hibiscus cannabinus L.) genetic resources from 10 countries to confirm the possibility of the introduction into Korea. The Kenaf (Hibiscus cannabinus L.) has the broad industrial use like feed and the 5 times more strong $CO_2$ absorption capacity compared to general plant. So recently it is considered as a good industrial source. We analyzed ecotype, growth and development, yield and feed value of collected resources. They were divided into 3 groups depending on flowering time, early maturing type blooming in early July, mid-late maturing type blooming from end of August to early September and late maturing type blooming in end of October. Early maturing type could get fruitful seed but dropped yield (average 7,895 kg/10a) and late maturing type could get high yield (average 12,572 kg/10a) but deletion. The other side mid-late maturing type could get yield over a certain level (average 11,207 kg/10a) and fruitful seed was ensured. The yields analyzed by resources indicated that K12 (Hongma 300) collected in China, K25 from India, K22 from Russia and K21 (Khonkaen 60) variety from China were more than 13,500 kg per 10a. Feed value of early maturing type had inclined to more better than other types, but like dry digestible matter (DDM) and dry matter intake (DMI) of some late maturing types like K12, K21, K22 which had a high yielding ability were more better than that of early maturing types'. So relative feed value (RFV) which considered comprehensive item for feed value were indicated K21 was 102.5, K12 was 116.2 and K22 was 120.2. 'Jangdae' the variety developed in Korea which could complement of other types' had a good quality for yield 10,975 kg/10a and 12.5% crude protein content and 101.9 of the relative feed value. So we need to be taken power to collection of mid-late maturing types resources.

• Journal of Food Hygiene and Safety
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• v.26 no.4
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• pp.308-314
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• 2011

This study surveyed and compared the temperatures established in display stands and food surfaces for cold and frozen foods in large discount stores in Korea. The temperatures established in display stands for cold food ranged with $3.5{\pm}1.8^{\circ}C$ as mean, minimum and maximum were $0^{\circ}C$ and $7^{\circ}C$. However, the surface temperatures of cold food on sale ranged with $10.7{\pm}2.9^{\circ}C$ as a mean, minimum $4.6^{\circ}C$ and maximum $18.4^{\circ}C$. Totally, the surface temperature of cold food on sale was $7.2^{\circ}C$, as a mean, higher than established in display stands for cold food in large discount stores in Korea. 53% of the surveyed cold foods were more than $10^{\circ}C$ in surface temperature and only 47% was less than $10^{\circ}C$. The differences between temperatures were lowest in fruits, salads and vegetables, but highest in milk products. On the other hand, the temperatures established in display stands for frozen food showed a range with $-20.7{\pm}1^{\circ}C$ as a mean. However, the surface temperatures of frozen food on sale showed a range with $-15.4{\pm}5^{\circ}C$ as a mean, minimum $-28^{\circ}C$ and maximum $-4.6^{\circ}C$ (included defrosting). The surface temperatures of frozen food, frozen meats, frozen processed foods and ice creams were $-13.8^{\circ}C$, $-15.9^{\circ}C$, and $-16.8^{\circ}C$, respectively. Only 32.3% of surveyed frozen foods showed less than $-18^{\circ}C$ in surface temperature. In conclusion, the temperatures established on cold and frozen food display stands were less than those of cold and frozen food surfaces on sale. There was also much variation in food surface temperatures during cold and frozen food storage and sales. Therefore, a temperature management system technology use at the distribution level for cold and frozen foods will be developed.