• Journal of Environmental Science International
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• v.17 no.1
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• pp.45-56
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• 2008

This study was to assess the lifetime cancer and non-cancer risk of exposure of worker and user at public facilities in Korea to volatile organic compounds (VOCs). We measured the concentrations of two aldehydes and five VOCs in indoor air at 424 public buildings that 8 kinds of public facilities (70 movie theaters, 86 offices, 86 restaurants, 70 academies, 22 auditoriums, 30 PC-rooms, 30 singing-rooms and 30 bars) all over the country. There were estimated the human exposure dose and risks with averages of the using-time and frequency for facility users and office workers, respectively. Carcinogens (formaldehyde, acetaldehyde, and benzene) were estimated the lifetime excess cancer risks (ECRs). non-carcinogens (toluene, ethylbenzene, xylene, and styrene) were estimated the hazard quotients (HQs). The average ECRs of formaldehyde and benzene for facility worker and user were $1{\times}10^{-3}{\sim}1{\times}10^{-4}\;and\;1{\times}10^{-4}{\sim}1{\times}10^{-5}$ level, respectively, in all facilities. HQs of four non-carcinogens did not exceed 1.0 for all subjects in all facilities. The estimated ECRs for restaurant and auditorium were the highest, and the PC-room and bar were the next higher facilities. Furthermore, people in a smoking facility had the highest cancer risk. Higher ECRs of formaldehyde and benzene were observed in indoor smoking facilities such as restaurant and auditorium. Higher HQs of toluene and xylene were observed at the restaurant and office building.

• Horticultural Science & Technology
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• v.17 no.3
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• pp.361-364
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• 1999

This study was conducted to examine the effects of pulsing treatment and to develop techniques treated right after harvest by grower for extending vase life and improving flower quality in cut freesia. Thirty minutes dipping treatment of STS 2 mM followed by 20 hr pulsing in sucrose 10% + BA 10 ppm + 8-HQS 300 ppm solution showed the best results in vase life and flower quality of cut freesia when kept in vase water. This pretreatment extended vase life by 24.7% than control, and improved quality of cut freesia significantly in flower diameter, percent flowering (35.4%), fresh weight, water uptake, and carotenoid content, and depressed ethylene production and respiration rate.

• Journal of the Korean Chemical Society
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• v.23 no.3
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• pp.141-151
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• 1979

The selective absorption of metal ions by chelating agent-loaded resins was studied in aqueous media. The resins were prepared by loading the conventional anion exchange resin, Dowex 1-X8 (50 to 100 mesh) with chelating agents containing sulfonic group, such as 8-hydroxy-quinoline-5-sulfonic acid (HQS) and 7-nitroso-8-hydroxyquinoline-5-sulfonic acid (NHQS). The stability of the resin was markedly influenced by the following factors; (1) the affinity and concentration of anions in the external solution, (2) the pH of the media. The optimum conditions for the absorption of metal ions were determined with respect to the pH, shaking time, and the effect of anion concentration in the medium. Under the optimum condition the order of the absorption of metal ions such as Fe(Ⅲ), Cu(Ⅱ), Pb(Ⅱ), and Zn(Ⅱ) was in accord with that of the stability constants of the chelates. The total capacities of the resins were found in the range of 0.6∼1.6 mmole metal per gram.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.3
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• pp.93-100
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• 2006

Modern versions of supersonic jet fighter aircraft using a digital flight-by-wire flight control system design utilizes a control surface reconfiguration in order to guarantee the aircraft flight stability when a control surface is failed. The T-50 flight control laws are designed such that the surface reconfiguration mode controls the aircraft using non-failed control surfaces when one of the control surfaces is failed. In this paper, linear analysis and HQS(Handling Quality Simulator) pilot simulations are performed to analyze the flight stability and handling quality when the surface reconfiguration mode is engaged for aircraft landing configuration. It is found that the aircraft flight stability and handling quality is satisfied to level 1 requirements when the T-50 flight control law is changed to the surface reconfiguration mode.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.8
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• pp.50-55
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• 2005

An advanced method of Relaxed Static Stability (RSS) is utilized for improving the aerodynamic performance of modern version supersonic jet fighter aircraft. The laws of flight control system utilize RSS criteria in both longitudinal and lateral-directional axes to achieve performance enhancements. Particularly, the design of longitudinal control laws for utilizing RSS methods greatly affects the performance of the aircraft in Air-to-Air Tracking and Air-to-Ground modes, which improves weapon delivery. In the area of Air-to-Air Tracking, the development of longitudinal control laws aids in the fine tracking and gross acquisition of other aircraft. This paper proposes that new concept of longitudinal control law introduce in order to improve fine tracking performance in air-to-air tracking maneuver. Result of HQS pilot simulation and flight test, fine tracking performance improve without degradation of gross acquisition when new concept of control law is applied.

• Horticultural Science & Technology
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• v.29 no.3
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• pp.217-223
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• 2011

This study was conducted to examine the effect of several pretreatments and holding solutions on the vase life and quality of cut Polygonatum odoratum var. pluriflorum for. variegatum stems native to Korea. Postharvest foliar spray of 200 $mg{\cdot}L^{-1}$ $GA_3$ or 200 $mg{\cdot}L^{-1}$ BA + 200 $mg{\cdot}L^{-1}$ $GA_3$ markedly extended the vase life of cut stems of Polygonatum odoratum var. pluriflorum for. variegatum. These treatments maintained high chlorophyll contents as compared with the control (distilled water) during senescence of cut stems. Postharvest pretreatment (dipping) with 100 $mg{\cdot}L^{-1}$ $GA_3$ or 3% sucrose + 200 $mg{\cdot}L^{-1}$ 8-hydroxyquinoline sulfate (HQS) + 100 $mg{\cdot}L^{-1}$ $GA_3$ for 16 hours extended vase life of cut stems 2.5 times as long as nontreated control. Holding solution of 2% sucrose + 200 $mg{\cdot}L^{-1}$ HQS + 100 $mg{\cdot}L^{-1}$ $GA_3$ significantly extended vase life by 3.5 times and increased fresh weight as compared with control. $GA_3$ were very effective on preventing leaf yellowing of cut Polygonatum odoratum var. pluriflorum for. variegatum stems. Postharvest foliar spray of 200 $mg{\cdot}L^{-1}$ $GA_3$ or holding solution of 2% sucrose + 200 $mg{\cdot}L^{-1}$ HQS + 100 $mg{\cdot}L^{-1}$ $GA_3$ markedly extended vase life and improved quality of cut stems of Polygonatum odoratum var. pluriflorum for. variegatum.

• Korean Journal of Plant Resources
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• v.24 no.4
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• pp.445-455
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• 2011

This study was performed to develop a natural preservative which had the most successful effect on prolonging the vase life of cut flowers Rosa hybrida 'Enjoy'. To determine the effect of sucrose on vase life of cut roses, R. hybrida 'Enjoy', 0, 1, 3 or 5% of sucrose was mixed with Hypnum jutlandicum extract. The result showed that in the case of adding sucrose to extracts from H. jutlandicum, vase life of cut flowers was shortened, along with the cut flowers losing chlorophyll, becoming decolorized and finally showing wilting phenomenon. However, using hydroxy quinoline sulfate (HQS) and extracts from H. jutlandicum together exhibited an improved effect of prolonging vase life, especially when adding 100 $mg{\cdot}L^{-1}$ HQS, which had the effect of prolonging the vase life of R. hybrida 'Enjoy' the most. Regarding pH of extracts, 2 $mg{\cdot}L^{-1}$ of extracts from H. jutlandicum show originally pH 3.8. This was compared with adjusted extract solutions as pH 3.0, 4.0 or 5.0. The results showed that the solution of pH 3.8 had the most successful effect on prolonging the vase life of R. hybrida 'Enjoy'. Given all the results, H. jutlandicum extract (2 $mg{\cdot}L^{-1}$) and HQS (100 $mg{\cdot}L^{-1}$) was the most effective in prolonging the vase life of cut R. hybrida 'Enjoy'. Moss is expected to be worth developing as a natural preservative since it is easy to get and causes no damage to the environment.

• Journal of Korea Trade
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• v.24 no.1
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• pp.82-98
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• 2020

Purpose - This study aims to overcome the limitations of existing studies, which linearly determine the precedence factors of competency in overseas subsidiaries. The research objectives are as follows. First, what kind of nonlinear effects does the level of control held by Korean headquarters over foreign subsidiaries have in terms of competency in the subsidiaries? Second, what kind of nonlinear effects do the local experiences of overseas subsidiaries have on their competency? Design/methodology - With data on Korean multinational corporations (MNCs), this paper analyzes the effects of control levels of headquarters (HQs) and host-country experiences of foreign subsidiaries regarding competency in overseas subsidiaries. In particular, this study focuses on nonlinear models, differentiating it from previous studies. In order to examine research hypotheses, this study conducted a survey of overseas subsidiaries of Korean corporations. Surveys were conducted through various methods including e-mail, online questionnaires, fax, and telephone calls. Copies of the questionnaire were distributed to a total of 2,246 overseas subsidiaries, and 409 completed responses were collected. Excluding 15 copies that were insufficiently answered, responses from a total of 394 copies were used for analysis. Findings - This study presents the following results. First, there is a U-shaped relationship between levels of HQ control and competency in foreign subsidiaries. This means that higher levels of HQ control negatively impact the competency levels of subsidiaries because strict control undermines autonomy in subsidiaries. However, if the level of HQ control exceeds a certain point, then the transfer of knowledge between HQs and subsidiaries is facilitated. Knowledge transferred from HQs can be used as prior knowledge by foreign subsidiaries to the benefit of all parties. Accordingly, knowledge transfer negates the negative effects of excessive HQ control and positively affects competency in subsidiaries. Second, there is an inverted U-shaped relationship between the local (host-country) experiences of subsidiaries and competency in foreign subsidiaries. This means that foreign subsidiaries can overcome the liabilities of foreignness and contribute to capability building by accumulating unique knowledge about their host countries. However, if local experiences accumulate excessively beyond a certain point, then the host country-specific experiences of foreign subsidiaries will offset the benefits discussed above. Excessive local experiences not only increase organizational inertia, but also create a problem of goal incongruence due to information asymmetry between HQs and subsidiaries. Therefore, excessive local experiences have negative effects on competency in foreign subsidiaries. Originality/value - This study suggests the following implications. First, unlike existing studies based mainly on linear models, this study presents important theoretical implications in its focus on nonlinear models and its analysis of the effects of HQ control and local experiences on competency in foreign subsidiaries from perspectives of organizational learning theory and agency theory. Second, in terms of practical implications, the results of this study suggest that optimally raising levels of HQ control and managing the local experiences of subsidiaries without increasing organizational inertia is important for enhancing competency in foreign subsidiaries.

• Journal of Environmental Health Sciences
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• v.44 no.6
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• pp.548-555
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• 2018

Objectives: We conducted ecological risk assessment for cadmium, a heavy metal and carcinogen, to identify safety standards by environmental media and to determine its impact on ecosystems by estimating and evaluating exposure levels. Methods: Species sensitivity distributions (SSDs) were generated using ECOTOX DB. A hazardous concentration of 5% (HC5) protective of most species (95%) in the environment was estimated. Using this estimate, predicted no effect concentrations (PNECs) were calculated for aquatic organisms. Based on the calculated PNECs for aquatic organisms, PNEC values for soil and sediment were calculated using the partition coefficient. Predicted exposure concentrations (PECs) were also calculated from environmental monitoring data with hazard quotients (HQs) calculated using PNECs for environmental media. Results: Chronic toxicity data were categorized into four groups and 11 species. In species sensitivity distribution (SSD) analysis, HC5 was $0.340{\mu}g/L$. Based on this value, the PNEC value for aquatic organisms was calculated as $0.113{\mu}g/L$. PNEC values for soil and sediments using a partition coefficient were calculated as 15.02 mg/kg and 90.61 mg/kg, respectively. In an analysis of environmental monitoring data, PEC values were calculated as $0.017{\mu}g/L$ for water, 1.01 mg/kg for soil, and 0.521 mg/kg for sediment. Conclusions: HQs were 0.150, 0.067 and 0.006 for water, soil and sediment, respectively. HQs of secondary toxicity were 0.365 for birds and 0.024 for mammals. In principle, it is judged that an HQ above 1 indicates a high level of risk concern while an HQ less than 1 indicates an extremely low level of risk concern. Therefore, with HQs of cadmium in the environment being <1, its risk levels can be considered low for each media.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.5
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• pp.57-64
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• 2005

Modern versions of supersonic jet fighter aircraft using digital flight-by-wire flight control system receive aircraft flight condition such as altitude, airspeed and AoA(angle of attack) from IMFP(Integrated Multi-Function Probe). IMFP sensors data have triplex structure using three IMFP sensors. An air data reconfiguration mode is applied to a T-50 flight control law to guarantee the aircraft flight stability when 2 or 3 IMFP sensors data are invalided. In this study, linear analysis and HQS(Handling Quality Simulator) pilot simulation are performed to analyze flight stability when the air data reconfiguration mode is applied to the control law. And we propose an example that the air data reconfiguration mode is applied to the control law due to second failure of IMFP during T-50 flight. It is found that the aircraft flight stability is not affected when the T-50 flight control law is changed to the air data reconfiguration mode.