• Restorative Dentistry and Endodontics
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• v.34 no.4
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• pp.324-332
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• 2009

The purpose of this study was to investigate the effect of rigidity of post core systems on stress distribution by the theoretical technique, finite element stress-analysis method. Three-dimensional finite element models simulating an endodontically treated maxillary central incisor restored with a zirconia ceramic crown were prepared and 1.5 mm ferrule height was provided. Each model contained cortical bone, trabecular bone, periodontal ligament, 4 mm apical root canal filling, and post-and-core. Six combinations of three parallel type post (zirconia ceramic, glass fiber, and stainless steel) and two core (Paracore and Tetric ceram) materials were evaluated, respectively. A 50 N static occlusal load was applied to the palatal surface of the crown with a $60^{\circ}$angle to the long axis of the tooth. The differences in stress transfer characteristics of the models were analyzed. von Mises stresses were chosen for presentation of results and maximum displacement and hydrostatic pressure were also calculated. An increase of the elastic modulus of the post material increased the stress, but shifted the maximum stress location from the dentin surface to the post material. Buccal side of cervical region (junction of core and crown) of the glass fiber post restored tooth was subjected to the highest stress concentration. Maximum von Mises stress in the remaining radicular tooth structure for low elastic modulus resin core (29.21 MPa) was slightly higher than that for high elastic modulus resin core (29.14 MPa) in case of glass fiber post. Maximum displacement of glass fiber post restored tooth was higher than that of zirconia ceramic or stainless steel post restored tooth.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.547-551
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• 2009

A new commercial rice variety "Chilbo" is a japonica rice (Oryza sativa L.) with resistance to rice stripe virus and high grain quality. It was developed by the rice breeding team of Yeongdeog Substation, NICS, RDA in 2007. This variety was derived from a cross between "Yeongdeog 26" with wind tolerance and lodging resistance and "Koshihikari" with good grain quality. A promising line, YR21324-119-3-2 was selected by a pedigree breeding method and designated as "Yeongdeog 44" in 2004. Regional adaptation yield trials were carried out at eleven locations from 2005 to 2007. As a result, "Yeongdeog 44" was released as a high yielding rice variety with high grain qualilty and virus resistance with the name of "Chilbo". It is short 76cm in culm length and has medium-late growth duration. This variety is resistant to stripe virus and middle resistant to leaf blast disease. It is also tolerant to cold, dried wind. Milled rice kernel of "Chilbo" is translucent, clear in chalkiness. Panel test proved that and it has good eating quality. Head rice ratio of Chilbo is high compared to the check variety, Hwaseongbyeo. Yield potential of "Chilbo" in milled rice is about 5.57MT/ha at ordinary fertilizer level of local adaptability test. This variety would be adaptable to Yeongnam plain, south & east-south coastal, south mid-mountainous, middle plain area of Korean peninsula.

• FLOWER RESEARCH JOURNAL
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• v.19 no.3
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• pp.127-138
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• 2011

Four different plant growth retardants (PGRs), paclobutrazol, flurprimidol, daminozide, and chlormequat, were applied to potted Saxifraga rosacea 'Kumoma' and 'Kumoma-Gusa' plants for control of the growth and flowering. Paclobutrazol (10, 20, 40, $80mg{\cdot}L^{-1}$), flurprimidol (5, 10, 20, $40mg{\cdot}L^{-1}$), daminozide (500, 1000, 2000, $4000mg{\cdot}L^{-1}$), and chlormequat (50, 100, 200, $400mg{\cdot}L^{-1}$) were applied to the plants by a foliar spray or drenching. In 'Kumoma', application of $40mg{\cdot}L^{-1}$ paclobutrazol by a foliar spray or drenching reduced plant height by 12.5 and 12.6 cm, and flower length by 3.4 and 3.3 cm, respectively. On the other hand, in 'Kumoma-Gusa', drenching of paclobutrazol reduced plant height by 10.7 to 12.6 cm and flower length by 2.0 to 3.9 cm with increasing concentration, but the number of florets almost fell to 20 as compared to 40.5 in the control. 'Kumoma-Gusa' plants drenched with $80mg{\cdot}L^{-1}$ paclobutrazol and sprayed with $40mg{\cdot}L^{-1}$ flurprimidol had the shortest heights of 10.7 and 9.9 cm, and floral length of 2.0 and 1.5 cm, respectively. A flurprimidol drenching at $40mg{\cdot}L^{-1}$ delayed the harvest by 3-13 days as compared to the control and the smallest number of florets, 15.6, was observed in this treatment. In both cultivars, chlormequat and daminozide did not effectively influence the growth and flowering. However, number of florets increased to more than 41 at all concentrations and up to 63, the greatest floret number, with chlormequat drench in 'Kumoma-Gusa'. These results demonstrated that over $40mg{\cdot}L^{-1}$ of paclobutrazol or 5 to $20mg{\cdot}L^{-1}$ of flurprimidol could be used as PGRs to control the growth of floral length and flowering for improving potted plant quality in S. rosacea 'Kumoma' and 'Kumoma-Gusa'.

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.288-291
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• 2009

A new commercial rice variety "Donghaejinmi" is a japonica rice (Oryza sativa L.) with lodging resistance and high grain quality. It has been developed by the rice breeding team of Yeongdeog Substation, National Institute of Crop Science (NICS), RDA. This variety was derived from a cross between "Milyang 64" as a resistance source of brown planthopper (Bph) and "Milyang 165" as grain quality source. The donor parent, "Milyang64" has been backcrossed three times with recurrent parent, "Milyang165" and selected by the pedigree breeding method. The pedigree of "Donghaejinmi", designated as "Yeongdeog 41" in 2003, was YR21259-B-B-68-1. It has a short culm length with 69 cm and medium-late growth time. This variety is resistant to stripe virus and moderately resistant to leaf blast disease with durable resistance. It also has tolerance to unfavorable environment such as cold, dried wind and storm. Milled rice kernel of "Donghaejinmi" is translucent, clear in chalkness and good at eating quality in panel test. The merit of this variety is high head rice ratio, which is essential element to produce an article of superior quality rice brand. The yield potential of "Donhaejinmi" in milled rice is about 6.05 MT/ha at ordinary fertilizer level of local adaptability test. This cultivar would be adaptable to Yeongnam inland plains and eastern costal area of Yeongnam province.

• Journal of Legislation Research
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• no.53
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• pp.177-211
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• 2017

In the course of the emergence and development of new ICT technologies and services such as Big Data, Internet of Things and Artificial Intelligence, the future will change by these new innovations in the Fourth Industrial Revolution. The future of this fourth industrial revolution will change and our future will be data-based society or economy. Since there is personal information at the center of it, the development of the economy through the utilization of personal information will depend on how to make the personal information protection laws. In Korea, which is trying to lead the 4th industrial revolution, it is a legal interest that can not give up the use of personal information, and also it is an important legal benefit that can not give up the personal interests of individuals who want to protect from personal information. Therefore, it is necessary to change the law on personal information protection in a rational way to harmonize the two. In this regard, this article discusses the problems of duplication and incompatibility of the personal information protection law, the scope of application of the personal information protection law and the uncertainty of the judgment standard, the lack of flexibility responding to the demand for the use of reasonable personal information, And there is a problem of reverse discrimination against domestic area compared to the regulated blind spot in foreign countries. In order to solve these problems and to improve the legislation of personal information protection in the era of the fourth industrial revolution, we proposed to consider both personal information protection and safe use by improving the purpose and regulation direction of the personal information protection law. The balance and harmony between the systematical maintenance of the personal information protection legislation and laws and regulations were also set as important directions. It is pointed out that the establishment of rational judgment criteria and the legislative review to clarify it are necessary for the constantly controversial personal information definition regulation and the method of allowing anonymization information as the intermediate domain. In addition to the legislative review for the legitimate and non-invasive use of personal information, there is a need to improve the collective consent system for collecting personal information to differentiate the subject and to improve the legislation to ensure the effectiveness of the regulation on the movement of personal information between countries. In addition to the issues discussed in this article, there may be a number of challenges, but overall, the protection and use of personal information should be harmonized while maintaining the direction indicated above.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.1-2
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• 2011

Hybrid rockets have lately attracted attention as a strong candidate of small, low cost, safe and reliable launch vehicles. A significant topic is that the first commercially sponsored space ship, SpaceShipOne vehicle chose a hybrid rocket. The main factors for the choice were safety of operation, system cost, quick turnaround, and thrust termination. In Japan, five universities including Hokkaido University and three private companies organized "Hybrid Rocket Research Group" from 1998 to 2002. Their main purpose was to downsize the cost and scale of rocket experiments. In 2002, UNISEC (University Space Engineering Consortium) and HASTIC (Hokkaido Aerospace Science and Technology Incubation Center) took over the educational and R&D rocket activities respectively and the research group dissolved. In 2008, JAXA/ISAS and eleven universities formed "Hybrid Rocket Research Working Group" as a subcommittee of the Steering Committee for Space Engineering in ISAS. Their goal is to demonstrate technical feasibility of lowcost and high frequency launches of nano/micro satellites into sun-synchronous orbits. Hybrid rockets use a combination of solid and liquid propellants. Usually the fuel is in a solid phase. A serious problem of hybrid rockets is the low regression rate of the solid fuel. In single port hybrids the low regression rate below 1 mm/s causes large L/D exceeding a hundred and small fuel loading ratio falling below 0.3. Multi-port hybrids are a typical solution to solve this problem. However, this solution is not the mainstream in Japan. Another approach is to use high regression rate fuels. For example, a fuel regression rate of 4 mm/s decreases L/D to around 10 and increases the loading ratio to around 0.75. Liquefying fuels such as paraffins are strong candidates for high regression fuels and subject of active research in Japan too. Nakagawa et al. in Tokai University employed EVA (Ethylene Vinyl Acetate) to modify viscosity of paraffin based fuels and investigated the effect of viscosity on regression rates. Wada et al. in Akita University employed LTP (Low melting ThermoPlastic) as another candidate of liquefying fuels and demonstrated high regression rates comparable to paraffin fuels. Hori et al. in JAXA/ISAS employed glycidylazide-poly(ethylene glycol) (GAP-PEG) copolymers as high regression rate fuels and modified the combustion characteristics by changing the PEG mixing ratio. Regression rate improvement by changing internal ballistics is another stream of research. The author proposed a new fuel configuration named "CAMUI" in 1998. CAMUI comes from an abbreviation of "cascaded multistage impinging-jet" meaning the distinctive flow field. A CAMUI type fuel grain consists of several cylindrical fuel blocks with two ports in axial direction. The port alignment shifts 90 degrees with each other to make jets out of ports impinge on the upstream end face of the downstream fuel block, resulting in intense heat transfer to the fuel. Yuasa et al. in Tokyo Metropolitan University employed swirling injection method and improved regression rates more than three times higher. However, regression rate distribution along the axis is not uniform due to the decay of the swirl strength. Aso et al. in Kyushu University employed multi-swirl injection to solve this problem. Combinations of swirling injection and paraffin based fuel have been tried and some results show very high regression rates exceeding ten times of conventional one. High fuel regression rates by new fuel, new internal ballistics, or combination of them require faster fuel-oxidizer mixing to maintain combustion efficiency. Nakagawa et al. succeeded to improve combustion efficiency of a paraffin-based fuel from 77% to 96% by a baffle plate. Another effective approach some researchers are trying is to use an aft-chamber to increase residence time. Better understanding of the new flow fields is necessary to reveal basic mechanisms of regression enhancement. Yuasa et al. visualized the combustion field in a swirling injection type motor. Nakagawa et al. observed boundary layer combustion of wax-based fuels. To understand detailed flow structures in swirling flow type hybrids, Sawada et al. (Tohoku Univ.), Teramoto et al. (Univ. of Tokyo), Shimada et al. (ISAS), and Tsuboi et al. (Kyushu Inst. Tech.) are trying to simulate the flow field numerically. Main challenges are turbulent reaction, stiffness due to low Mach number flow, fuel regression model, and other non-steady phenomena. Oshima et al. in Hokkaido University simulated CAMUI type flow fields and discussed correspondence relation between regression distribution of a burning surface and the vortex structure over the surface.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.2
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• pp.111-118
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• 2016

Acne vulgaris is a chronic inflammatory condition characterized by comedo, papule, cyst, nodule and postinflammatory hyperpigmentation. Meanwhile, it is also induced by adverse event of drugs. Among them, acneiform folliculitis is a side effect of epidermal growth factor receptor (EGFR) inhibitor, which is an anticancer agent, and its incidence may occur in upward of 75 ~ 100% of cases. The main method of acne vulgaris treatment is oral antibiotics, retinoids, topical medication and so on. However, it is limitation that teratogenicity caused by retinoids and antibiotic resistance increased by using antibiotics. In this study, we aimed to evaluate the clinical efficacy and safety of topical recombinant human (rh) EGF in treating facial acne vulgaris. Twenty three Koreans (age: 10 ~ 29 years) with mild to moderate acne vulgar participated in the study and applied topical rhEGF cream (trouble control EGF) with 3 products (trouble control clarifying cleansing foam, trouble control all-clear filling toner, redroll calming moisture) on their face twice daily for four weeks. Several assessment methods were applied: Acne lesion counts score by investigator's global assessment, efficacy and satisfaction score by subjects. Skin sebum output level, hydration level and redness level were also measured at each visit. At the final visit, skin sebum level, transepidermal water loss, skin redness statistically decreased and acne lesions (comedone, papule) were statistically reduced. No severe side effects were observed during the study. In conclusion, topical rhEGF seems to be an effective and safe adjuvant treatment option for mild acne vulgaris.

• Korea journal of population studies
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• v.11 no.2
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• pp.33-53
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• 1988

This study aimed at developing a desirable family planning policy and strategy by examining the current status of family planning practice in rural Korea and by indentifying the crucial factors which affect fertility control behavior. For this purpose, an analytical study was conducted, using the survey data collected in July 1985, on an interview basis, on 1, 440 married women living in the Soyi, Wonnam and Maingdong townships of Eumseong County(in North Chungcheong Province). This study population has the typical characteristics of rural areas, and the results of the analysis can be summarized as follows: 1. In regard to the demographic characteristics of the study population : their average age at marriage was 23.7, they had an average of 2.6 children( 1.3 boys, 1.3 girls) :10% experienced the death of their child (ren) :14% had spontaneous abortion(s) :4% weathered stillbirth(s) :35% went through induced abortion (s) : and 5.5% were currently pregnant. The average of their ideal numbers of children was 2.2, while 44% felt that they must have a son. 2. Looking at the contact rate with medical & health institutions, over the past 1 year, the visit rate to health subcenters was 43.7%, while 26.9% visited the (county) health center :59.6% had been to private clinics : and 41.5% went to the Soonchunhyang - Eumsung hospital : thus showing a relatively high rate of accessibility. 3. The utilization rate of family planning services was 76.5%, with tubectomy being the most prominent method at 52.3%, while the informants were health workers in 54.2% of the acceptors. Of the 8.4% who discontinued the use of contraceptive methods, only 26% did so due to want for pregnancy, natural infertility (meno - pause), or other reasons, while the remaining 74% stopped usage on account of side effects, failure in the methods themselves, and inconvenience of use, thus pointing to a situation where the proper choice of family planning methods have not yet been made. It can be noted that there is a strong motivation for early birth stopping as 35.3% practice family planning even with only one child, of which 38.3% have had sterilization operations. According to results of a multiple regression analysis, among the variables affecting contraception usage the most significant variable was the number of sons. 4. 34.8% experienced induced abortions. It was shown as a result of multiple regression analysis that the number of children and attitudes toward induced abortions extensively affected their frequency of abortions conducted. 5. In the regard to the relation between family planning and induced abortions, 33.7% of the women used both, while 52.0% of them used only the former(family planning), with only 1.4 % utilizing solely the latter(abortion), and 12.9% totally abstaining from fertility regulation : again, the discriminant analysis indicated that the choice of family planning and/or induced abortion was determined by the number of children and attitudes toward induced abortion. In view of the above mentioned results, the following are some comments and suggestions concerning problems related to the current family planning policies, in Korea : 1. It is difficult to expect a further quantitative expansion in family planning program operations, as there has been an excessive supply of target-oriented sterilization operations on women. From a maternal and child health care point of view, it will be desirable to have a diversification of service points in the future where family planning methods may be properly chosen, so that choices of methods which suit the mothers' characteristics and tastes may be made by the individuals themselves by strengthening their quality of family planning information services. 2. Along with the strengthening of the qualitative improvement of family planning services policies must be implemented to effectively promote the moral (ethical) deterrents to induced abortions and to preference for sons. From a maternal care standpoint, the social permissive norm toward induced abortion must be modified, and the bias towards son must be analyzed as the women with more daughters have a lower rate of family planning acceptance. Such changes in attitudes, however, can not be hoped to be accomplished with ad hoc policies, but will only be possible when an enhancement of the women's status(within the society) is brought about in a long - term perspective.

• Korean Journal of Plant Resources
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• v.20 no.5
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• pp.383-388
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• 2007

This study examined the effective treatment method of selenium and translocation characteristics of selenium in order to produce mungbean containing selenium. The foliar application of selenium at 3.5, 7, 14, and $28mg/{\ell}$ during the flowering period, yielded a relatively high record of seeds containing $0.41{\sim}3.96mg/kg$ and $0.27{\sim}2.38mg/kg$ of selenium, from the first and second harvesting. However, seeds from the first harvesting contained $52{\sim}71%$ more selenium than the seeds from the second harvesting. On the other hand, seeds from first and second harvesting of the non-treatment group had the same amount of selenium at 0.02mg/kg only. When the foliar application of selenium at $7mg/{\ell}$ was conducted two or three times, seeds from the first to third harvesting contained just the equal amount of selenium. However, when it was conducted only once, seeds from the first harvesting contained 56% and 67% more than seeds from the second and third harvesting, respectively. In seeds of mungbean containing 2.05mg/kg of selenium, cotyledon had 2.99mg/kg of selenium, which was 38% more than seed coat per unit weight. When mungbean sprout was produced, selenium content was 5.51mg/kg, but seed coats by-product of sprouts had 0.78mg/kg of selenium. The growth and quantity of mungbean was not significantly different according to the concentration and the frequency of foliar application of selenium used for in study.

• Korean Journal of Plant Resources
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• v.31 no.4
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• pp.283-293
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• 2018

This study was performed to analysis of chemical constituent in Polygonum multiflorum root (PMR) by different dry methods (hot-air dry, shade dry, and freeze dry). The results are summarized as followings; major free sugar were detected fructose, glucose, and sucrose in dried PMR based on various dry methods. The highest content of free sugars was found in freeze dried PMR. The four organic acids were detected in dried PMR by HPLC analysis. The content of oxalic acid in shade dried PMR was higher than the dried PMR by different dry methods. The content of total amino acid and essential amino acids were high in the orders of freeze drying > shade drying > hot-air drying. The potassium and magnesium levels of freeze dried PMR was significantly higher than the other drying method of PMR. Whereas the calcium and sodium levels were higher in hot-air dried PMR. The major fatty acids were determined the linoleic acid in PMR by different dry methods.