• Horticultural Science & Technology
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• v.28 no.3
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• pp.456-461
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• 2010

A study was conducted to investigate the effect of topophysis, and uniting method of rootstock and scion on rooting and subsequent growth of stenting-propagated cut rose ($Rosa$ $hybrida$ Hort.) in an effort to develop an efficient stenting propagation method for domestic rose cultivars. Four cultivars used in this study were two standard type cultivars 'Sweet Yellow' and 'Hanmaum', and two spray type cultivars 'Chelsi' and 'May'. Scions were grafted on cuttings of a rootstock $Rosa$ $indica$ 'Major'. The stenting-propagated scion-rootstock unions were planted in rockwool cubes ($50{\times}50{\times}50mm$, Delta, Grodan, Denmark) and were placed in a graft-take chamber for five days before being placed on misted greenhouse beds. The rootstock was removed of all leaves and nodes. Both the base of scions and top of stocks were simultaneously cut at a $45^{\circ}$ angle for grafting. Scions were prepared as single node cuttings, each with a five-leaflet leaf. Three positions of topophysis used were 7-9th (top), 4-6th (middle), and 1st-3rd (bottom) nodes from the stem base. Four uniting materials used were tube, tube + parafilm wrap, tube + clothespin, and clothespin. Rooting and growth were affected by the topophysis and cultivar. The best topophysis for rooting was 7-9th (top) nodes in all cultivars. Topophysis affected percent rooting, and number of roots, length of the longest root, and but not weight, shoot length and graft-take. Rooting and growth were affected by the uniting method and cultivar. Tube uniting method generally showed higher percentage graft-take, percent rooting, and number of roots than other methods. However, rootstock and scion union was not complete in this treatment. On the whole, the greatest rooting and subsequent growth of stenting-propagated plants were found in the tube + clothespin method. Except 'Sweet Yellow', rooting and growth were not adequate in the clothespin method. The results suggested that a tube + clothespin method was the most effective, and this method may be used as a substitute to save labor compared to a tube + parafilm wrap method which is currently being used in commercial nurseries.

• Applied Chemistry for Engineering
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• v.19 no.3
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• pp.299-303
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• 2008

A thermally cross-linkable polymer, poly[(2,5-dimethoxy-1,4-phenylenevinylene)-alt-(1,4-phenylenevinylene)] (Cross-PPV), was synthesized by the Heck coupling reaction. In order for the polymer to be cross-linkable, 20 mol% excess divinylbenzene was added. The chemical structure of Cross-PPV and thermally crosslinked Cross-PPV were confirmed by FT-IR spectroscopy. From the FT-IR, UV-Vis, and PL spectral data, thermally crosslinked Cross-PPV was insoluble in common organic solvents. The HOMO and LUMO energy level of thermally cross-linked Cross-PPV were estimated -5.11 and -2.56 eV, respectively, which were determined by the cyclic voltammetry and UV-Vis spectroscopy. From the energy level data, one can easily notice that thermally crosslinked Cross-PPV can be used for hole injection layer effectively. Bilayer structured device (ITO/crosslinked Cross-PPV/PM-PPV/Al) was fabricated using poly(1,4-phenylenevinylene-(4-dicyanomethylene-4H-pyran)-2,6-vinylene-1,4-phenylenevinylene-2,5-bis(dodecyloxy)-1,4-phenylenevinylene (PM-PPV) as the emitting layer, which have HOMO and LUMO energy levels of -5.44 eV and -3.48 eV, respectively. The bilayered device had much enhanced the maximum efficiency (0.024 cd/A) and luminescence ($45cd/m^2$) than those of a single layer device (ITO/PM-PPV/Al, 0.003 cd/A, $3cd/m^2$). The enhanced performance originated from that fact that cross-linked Cross-PPV facilitatse the hole injection to the emissive layer and the injected hole and electron from ITO and Al are recombined in emitting layer (PM-PPV) effectively.

• Korean Journal of Food Science and Technology
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• v.40 no.2
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• pp.123-128
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• 2008

The MRLs (maximum residue limits) of DDT (DDD and DDE) in fresh ginseng, dried ginseng, and steamed red ginseng are set as low as 0.01 mg/kg, 0.05 mg/kg, and 0.05 mg/kg, respectively. Therefore, this study was undertaken to develop a simple and highly sensitive analysis method, as well as to reduce interfering ginseng matrix peaks, for the determination of DDT isomers (o,p'-DDE, p,p'-DDE, o,p'-DDD, p,p'-DDD, o,p'-DDT, and p,p'-DDT) in fresh ginseng, dried ginseng, and steamed red ginseng at the 0.01 mg/kg level. The method used acetonitrile extraction according to simultaneous analysis, followed by normal-phase Florisil solid-phase extraction column clean-up. The purification method entailed the following steps: (1) dissolve the concentrated sample extract in 7 mL hexane; (2) add 3 mL of $H_2SO_4$; (3) vigorously shake on avortex mixer; (4) cetrifuge at 2000 rpm for 5 min; (5) transfer 3.5 mL of the supernatant to the Florisil-SPE (500 mg/6 mL);and (6) elute the SPE column with 1.5 mL of hexane and 10 mL of ether/hexane (6:94). The determination of DDT isomers was carried out by a gas chromatography-electron capture detector (GC-${\mu}$ECD). The hexane and ether/hexane (6:94) eluate significantly removed chromatographic interferences, and the addition of 30% $H_2SO_4$ to the acetonitrile extract effectively reduced many interfering ginseng matrix peaks, to allow for the determination of the DDT isomers at the 0.01 mg/kg level. The recoveries of the 6 fortified (most at 0.01 mg/kg) DDT isomers from fresh ginseng, dried ginseng, and steamed red ginseng ranged from 87.9 to 99.6%. The MDLs (method detection limits) ranged from 0.003 to 0.009 mg/kg. Finally, the application of this method for the determination of DDT isomers is sensitive, rapid, simple, and inexpensive.

• Journal of Legislation Research
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• no.41
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• pp.87-123
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• 2011

Korea is expected to become an 'aged society' with more than 14 percent of the public aged 65 years or more by 2018. The rapid aging is giving rise to various problems within the society along with falling birthrate in a short period of time. In this context, the role and function of laws on welfare for the aged must be particularly emphasized. Also the Senior Citizens Welfare Act is of great importance as it provides social welfare service on the basis of functional connection with social insurance and public assistance. First, this paper looks into the history of laws related to welfare for the elderly such as the Senior Welfare Act, the Act on Long-term Care Insurance for Senior Citizens and the Basic Old Age Pension Act as well as the findings of earlier studies. In the second place, it will break down such laws by main components aiming to examine details of the laws and questions raised regarding them and to seek ways to achieve improvement with an emphasis on health care, old age income security, housing welfare(assisted living facilities), job security for the aged. The Senior Welfare Act offers substance of social welfare service for the elderly. Income security, health and medical care, welfare measures through long-term care and assisted living facilities, social participation by working are the key elements and all of them should be closely associated to ensure citizens get sufficient public support in their old age. For this purpose, the Senior Welfare Act is under a normative network with laws such as Act on Long-term Care Insurance for Senior Citizens and Basic Old Age Pension Act. Current laws on welfare for the aged including Senior Welfare Act are not sufficiently responsive to the aged society of the 21st century. Income security combined with decent social participation, health and medical care closely connected with long-term care system, efficient expense sharing between government and local government, enhancement of effectiveness of welfare measures can be considered as means to improve current welfare system so that the elderly can enjoy their old age with dignity and respect.

• Journal of Wetlands Research
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• v.20 no.4
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• pp.363-369
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• 2018

One of the recent environmental problems is climate change due to the increase of atmospheric $CO_2$, which causes ecological changes and various environmental problems. Therefore, various studies are being carried out to reduce $CO_2$ in the world in order to solve various environmental problems caused by increase of $CO_2$. The $CO_2$ reduction using microalgae is an environmentally friendly method by using photosynthesis reaction of microalgae. However, most studies using single species. There is no study on the $CO_2$ fixing efficiency of microalgae in natural rivers. Therefore, this study was to identify the microalgae in the Sum river and to analyze the growth characteristics of microalgae in the river to obtain optimal culture conditions. And the changes of biomass and chlorophyll-a of microalgae were analyzed according to $CO_2$ concentration and injection rate. The purpose of this study was to investigate the fixing efficiency of carbon dioxide in microalgae in natural rivers. Six kinds of dominant species were observed as a result of the identification of microalgae in Sum river(Ankistrodesmus falcatus, Scenedesmus intermedius, Selenodictyum sp., Xanthidium apiculatum var. laeve, Cosmarium pseudoquinarium, Dictyosphaerium pulchellum). All of these species were green algae. Biomass and chlorophyll-a increased with the increase of $CO_2$ concentration and biomass and chlorophyll-a increased faster flow rate at the same $CO_2$ concentration. Also, the quantity of $CO_2$ fixation on the microalgae tended to be higher when the flow rate of injected gas was faster. This study can be referred as being significant in the micro-algae in river. In addition, the optimal conditions for $CO_2$ fixation of microalgae in rivers and the quantification of the quantity of $CO_2$ fixation from microalgae in rivers can be used as basic data for future policy of $CO_2$ reduction.

• Clean Technology
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• v.25 no.3
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• pp.245-255
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• 2019

Pressurized oxy-fuel combustion is a promising technology for $CO_2$ capture with a benefit of improving power plant efficiency compared with atmospheric oxy-fuel combustion. Prior to $CO_2$ compression in this process, a flue gas condenser (FGC) is used to remove $H_2O$ while recovering the latent heat. At the same time, the FGC has a potential for high-efficiency removal of $SO_x$ and $NO_x$ by exploiting their good solubility in water. In this study, experiments were carried out in a lab-scale, direct contact FGC under different pressures varying between 1 and 20 bar to evaluate the removal efficiency of $SO_2$ and $NO_x$ for individual gases and their mixture. In the tests for individual gases, 20% and 76% of $NO_x$ was removed at 1 bar and 10 bar, respectively. Even higher removal efficiencies were achieved for $SO_2$, and also these were maintained for longer as the pressure increased. In the tests for $SO_2$ and $NO_x$ mixture, the removal efficiency of $NO_x$ increased from 13% at 1 bar to 56% at 20 bar because of higher solubility at elevated pressures. $SO_2$ in the mixture was initially dissolved almost completely and then increased by 1,219 ppm at 1 bar and by 165 ppm at 20 bar. Overall, the removal efficiency of $SO_2$ and $NO_x$ was increased at elevated pressures, but it was lower in the mixture compared with individual gases at identical conditions because of a lower pH and associated chemical reactions in water.

• Journal of the Korean Applied Science and Technology
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• v.36 no.1
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• pp.324-332
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• 2019

Most countries including Korea and Indonesia have strong policy for implementing biofuels like biodiesel. Shortage of the oil feedstock is the main barrier for increasing the supply of biodiesel fuel. In this study, in order to improve the stability of feedstock supply and lower the biodiesel production cost, the feasibility of biodiesel production using two types of Indonesian tropical crop oils, pressed at different harvesting times, were investigated. R. Trisperma oils, a high productive non-edible feedstocks, were investigated to produce biodiesel by esterification and transesterification because of it's high impurity and free fatty acid contents. the kindly provided oils from Indonesia were required to perform the filtering and water removal process to increase the efficiency of the esterificaton and transesterification reactions. The esterification used heterogeneous acid catalyst, Amberlyst-15. Before the reaction, the acid value of two types oil were 41, 17 mg KOH/g respectively. After the pre-esterification reaction, the acid value of oils were 3.7, 1.8 mg KOH/g respectively, the conversions were about 90%. Free fatty acid content was reduced to below 2%. Afterwards, the transesterification was performed using KOH as the base catalyst for transesterification. The prepared biodiesel showed about 93% of FAME content, and the total glycerol content was 0.43%. It did not meet the quality specification(FAME 96.5% and Total glycerol 0.24%) since the tested oils were identified to have a uncommon fatty acid, generally not found in vegetable oils, ${\alpha}$-eleostearic acid with much contents of 10.7~33.4%. So, it is required to perform the further research on reaction optimization and product purification to meet the fuel quality standards. So if the biodiesel production technology using un-utilized non-edible feedstock oils is successfully developed, stable supply of the feedstock for biodiesel production may be possible in the future.

• Journal of the Korean Society of Radiology
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• v.79 no.5
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• pp.254-258
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• 2018

Purpose: Establishment of an appropriate protocol for breast magnetic resonance imaging (MRI) in the study of image quality standards to enhance the effectiveness of medical image information exchange, which is part of the construction and activation of clinical information exchange for healthcare informatization. Materials and Methods: The recommended protocols of breast and MRI scans were reviewed and the questionnaire was prepared by a responsible researcher. Then, a panel of 9 breast dedicated radiologists was set up in Korea. The expert panel conducted a total of three Delphi agreements to draw up a consensus on the breast MRI protocol. Results: The agreed breast MRI recommendation protocol is a 1.5 Tesla or higher device that acquires images with prone position using a breast dedicated coil and includes T2-weighted and pre-contrast T1-weighted images. Contrast enhancement images are acquired at least two times, and include 60-120 seconds between images and after 4 minutes. The contrast enhancement T1-weighted image should be less than 3 mm in thickness, less than 120 seconds in temporal resolution, and less than $1.5mm^2$ in-plane pixel resolution. Conclusion: The Delphi agreement of the domestic breast imaging specialist group has established the recommendation protocol of the effective breast MRI.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.293-301
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• 2019

The experiment was conducted to determine the performance of DME combustion gas when used as a fuel for DME burner for raising temperature and $CO_2$ concentration in greenhouse and also to examine its effects on chlorophyll content, and fresh and dry weight of lettuce and Chinese cabbage. DME-1 and DME-2 treatments consisted of average DME flow quantity in duct were $17.4m^3min^{-1}$ and $10.2m^3min^{-1}$ respectively to greenhouse-1 and greenhouse-2 and no DME gas was supplied to greenhouse-3 which was left as control (DME-3). DME supply times were $0.5hr\;day^{-1}$, $1hr\;day^{-1}$, $1:30hrs\;day^{-1}$ and $2hrs\;day^{-1}$ on week 1, 2, 3, and 4 respectively. Chlorophyll content and fresh and dry weight of lettuce and Chinese cabbage were measured for each treatment and analyzed through analysis of variance with a significance level of P<0.05. The result of the study showed that $CO_2$ concentration increased up to 265% and 174% and the level of temperature elevated $4.8^{\circ}C$ and $3.1^{\circ}C$ in greenhouse-1 and 2, respectively as compared to greenhouse-3 due to application of DME combustion gas. Although, the same crop management practices were provided in greenhouse-1, 2 and 3 at a same rate, the highest change (p<0.05) of chlorophyll content, fresh weight and dry weight were found from the DME-1 treatment, followed by DME-2. As a result, DME combustion gas that raised the level of temperature and $CO_2$ concentration in the greenhouse-1 and greenhouse-2, might have an effect on growth of lettuce and Chinese cabbage. At end of experiment, the highest fresh and dry weight of lettuce and Chinese cabbage were measured in greenhouse-1 and followed by greenhouse-2. Similarly chlorophyll content of greenhouse-1 and greenhouse-2 were more compared to greenhouse-3. In general, DME was not producing any harmful gas during its combustion period, therefore it can be used as an alternative to conventional fuel such as diesel and liquefied petroleum gas (LPG) for both heating and $CO_2$ supply in winter season. Moreover, endorsed quantify of DME combustion gas for a specified crop can be applied to greenhouse to improve the plant growth and enhance yield.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.6
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• pp.131-144
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• 2021

The organizational ambidexterity is an organizational strategy designed to pursue exploration activities to seize new opportunities and exploitation activities to efficiently use resources. Most of these ambidextrous structures have been studied for large corporations with slack resources, and there are still not many studies on the necessity of an ambidextrous structure for startups with relatively low-level resources. However, recently, the startup ecosystem is being advanced globally, and the amount of VC investment is rapidly increasing. This is a time when a lot of venture fund is invested in startups and a startup-friendly environment for rapid growth is created. This is the time to discuss the necessity and applicability of an ambidextrous organizational structure for startups. Therefore, this study conducted a hypothesis test whether the importance and necessity of balance that startups solving market problems with new ideas and utilizing accumulated resources have. To conduct this study, we analyzed 140 startups data gathered from the survey and the moderation effect was also analyzed. As a result of the study, it was verified that the balance of startup exploration and exploitation had a significant effect on startup performance, and the moderating effect of environmental dynamics was found to have a significant effect on the relationship with non-financial performance. Therefore, for startups with insufficient resources, it was concluded that the surplus resources generated in the process of a firm's growth should be effectively utilized and the balance between exploration and exploitation should be balanced from the initial stage of searching for a new business. In other words, it was confirmed that it is important for continuous growth and survival to seek the structure of an ambidextrous organization in order to internalize a mechanism that enables startups to pursue both effectiveness and efficiency in the long term. This study suggests a strategic direction for the growth of startups from the perspective of organizational structure. We expect that this meaningful results on the relationship between the ambidextrous capabilities of startups and performance contribute to the growth of startups in the rapidly growing startup venture environment.