• Korean Journal of Microbiology
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• v.38 no.1
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• pp.13-18
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• 2002

Effects of divalent cations such as $Mg^{2+}$, $Mn^{2+}$ and $Zn^{2+}$ on the self-splicing inhibition of the T4 phage thymidylate synthase (td) intron by the coenzyme thiamine pyrophosphate have been investigated. The splicing activity increased in proportion to the concentration of $Mg^{2+}$ up to 30 mM. Without $Mg^{2+}$in the splicing reaction the $Zn^{2+}$ ion tested in the range of 0.1-6 mM concentration only produced the splicing activity about 20% that of the normal splicing rate. A majority of the splicing products were I-E2 and E2 but El-E2 ligation product, Cl and Ll were not detected. Similar patterns of splicing products were also observed with $Mn^{2+}$. At 6 mM $Zn^{2+}$the intron RNA was hydrolyzed. $Mn^{2+}$produced a little higher splicing activity than that of $Zn^{2+}$over the range of concentrations used and at 8 mM about 28% splicing activity was observed. In contrast, $Mn^{2+}\;and\;Zn^{2+}$ ions promoted the splicing activity about 35-40% on an average in the presence of 10 mM $Mg^{2+}$. Of all divalent cations tested, $Mg^{2+}$exhibited the maximum activation effect to counteract the splicing inhibition by thiamine pyrophosphate. This appears to be due to the stabilizing effect of td intron ribozyme structure essential for the catalytic function by $Mg^{2+}$.

• Bulletin of the Korean Chemical Society
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• v.29 no.6
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• pp.1149-1156
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• 2008

The conformational study on neutral and zwitterionic L-alanines (N-Ala and Z-Ala, respectively) and the transition state (TS) for their interconversion is carried out using ab initio HF and density functional B3LYP methods with the self-consistent reaction field method in the gas phase and in solution. At both the HF and B3LYP levels of theory, the local minimum N1 for N-Ala is found to be most preferred in the gas phase and a weak asymmetric bifurcated hydrogen bond between the amino hydrogens and the carbonyl oxygen appears to play a role in stabilizing this conformation. The local minima N2a and N2b are found to be the second preferred conformations, which seem to be stabilized by a hydrogen bond between the amino nitrogen and the carboxylic hydrogen. The relative stability of the local minimum N2b is remarkably increased in solution than that in the gas phase. The local minimum N2b becomes more stable than the local minimum N2a in most of the solution. On the whole the relative free energies of Z-Ala and TS become more lowered, as the solvent polarity increases. N-Ala prevails over Z-Ala in aprotic solutions but Z-Ala is dominantly populated in ethanol and water. In aprotic solutions, the population of Z-Ala increases somewhat with the increase of solvent polarity. The barrier to Z-Ala-to-N-Ala interconversion increases on the whole with the increase of solvent polarity, which is caused by the increase of stability for Z-Ala.

• Environmental and Resource Economics Review
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• v.21 no.2
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• pp.417-439
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• 2012

Recently, the Korean government has announced a stream of countermeasures for stabilizing petroleum product prices. Especially, the Fair Trade Commission proposed a transaction guideline focusing on the petroleum-product blending. The main purpose of this study is to suggest the policy options to induce and promote petroleum-product blending. For this purpose, this paper describes the changes in domestic systems related to petroleum-product blending. In addition, it discusses the major topics for inducing and promoting petroleum-product blending. It would be prerequisites to alleviate or demolish the requirements of separate storage by supplier and exclusive dealing. These options would result in the price decreases at the stages of refinery and gas station. Due to the legal constraint of law revision, it should be also considered to increase more gas stations in wholesale marts and self or franchised independent gas stations.

• Korean Journal of Agricultural Science
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• v.47 no.2
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• pp.337-347
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• 2020

Since 2012, despite the fact that tariff rate quotas (TRQ) in the form of dried peppers has not been imported, the imports of pepper-related items such as low- tariff frozen peppers (27%) and other sauces (45%) have increased, there has been a problem in the domestic pepper industry, in which the domestic self-sufficiency rate has declined. The purpose of this study was to find out whether the operation of chili pepper TRQ has the effect of suppressing the imports of pepper-related items from China. We analyzed the import substitution effect (import suppression effect) through causal analysis of the imports of red pepper TRQ, frozen peppers, and other sauces using the structural equation model analysis method. As a result of the hypothetical scenario analysis, when the government imports and releases 7,185 tons of pepper TRQ in 2019/20 (scenario), private imports were estimated to decrease by only 3,060 tons. In other words, the import substitution effect between imported items was estimated to decrease about 2,079 tons of private dried peppers, and about 981 tons of imported pepper-related items. There was an effect of suppressing the imports of pepper-related items such as frozen peppers, but it was analyzed to be insignificant. That reason was that the replacement substitution elasticity of the pepper-related items for TRQ import was less than 1 (inelastic). Therefore, it is judged that the government's operation of the pepper TRQ is preferably focused on stabilizing domestic prices rather than focusing on import control of pepper-related items.

• Journal of Auto-vehicle Safety Association
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• v.14 no.2
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• pp.57-69
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• 2022

Recently, as interest in self-driving cars has increased worldwide, research and development on the Advanced Driver Assist System is actively underway. Among them, the purpose of Adaptive Cruise Control (ACC) is to minimize the driver's driving fatigue through the control of the vehicle's longitudinal speed and relative distance. In this study, for the research of the ACC test in the real environment, the real-road test was conducted based on domestic-road test scenario proposed in preceding study, considering ISO 15622 test method. In this case, the distance measurement method using the dual camera was verified by comparing and analyzing the result of using the dual camera and the result of using the measurement equipment. As a result of the comparison, two results could be derived. First, the relative distance after stabilizing the ACC was compared. As a result of the comparison, it was found that the minimum error rate was 0.251% in the first test of scenario 8 and the maximum error rate was 4.202% in the third test of scenario 9. Second, the result of the same time was compared. As a result of the comparison, it was found that the minimum error rate was 0.000% in the second test of scenario 10 and the maximum error rate was 9.945% in the second test of scenario 1. However, the average error rate for all scenarios was within 3%. It was determined that the representative cause of the maximum error occurred in the dual camera installed in the test vehicle. There were problems such as shaking caused by road surface vibration and air resistance during driving, changes in ambient brightness, and the process of focusing the video. Accordingly, it was determined that the result of calculating the distance to the preceding vehicle in the image where the problem occurred was incorrect. In the development stage of ADAS such as ACC, it is judged that only dual cameras can reduce the cost burden according to the above derivation of test results.

• Journal of the Korean Society of School Health
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• v.1 no.2
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• pp.86-117
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• 1988

The purpose of school lunch service programs (SLPs) is to provide school children with nutritious meals each day, to assist them in improving their mental and physical development, to make them understand the basic knowledge needed for healthy daily living throughout their lives with sound nutritional habits, and further, to enhance the national health status as well as the individual. The major purpose of this study is to describe the history and current status and promotional plans in Korea's SLSPs to improve the nation's health status. The major findings of this study are as follow: 1) The progression of the SLSPs can be devided into four major periods: Relief (1953-1972), Self-supportive (1973-1977), System-establishment (1973-1983), System-development(1984- ). 2) As result of the implementation of SLSPs in Korea, many positive effects have been found in school education, notably in the field of physical growth, social development and personality cultivation. 3) This study deals with a more detailed assessment with regard to the effects of the program on school education activities and the improvement of nutritional habits in the family. Although it is limited and not yet complete, the program implementation has contributed to the improvement in children's food-intake habits, understanding of food, and manners, and increased sanitary consciousness. It has also affected of parent's concerns and attitudes towards the improvement of daily meals as well as national eating patterns, and eventually provided motivation for increased farm production of nutritious food stuffs and reasonable food consumption. 4) The SLSPs does have its stare of problem such as an unsatisfactory budget, lack of understanding of the program by school personnel and parents. However, there is no doubt that the SLSPs should be carried out effectively for better health, and especially for the growth and development of the children. Finally, the problems and promotive Plans of the SLSPs can be approached by aspects of the administrative, financial and operational systems. These system have to coordinate with relevant authorities to expand participation in the program for the successful implementation of the SLSPs. The eventual objective this study is to propose ways and means for mobilizing every available element in the effort to attain the goals of educating and training healthy and competent personnel manpower, stabilizing the demand and supply of food and the ensuring adequate coordination of national food production and consumption.

• The Journal of the Korea Contents Association
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• v.20 no.5
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• pp.222-235
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• 2020

This study examines the poverty progress and its factors which drove the lives of the middle-aged men in Chokbang area. The observed examples are the retired government officials and the self-employed who have been classified as the ones in the economically-middle class but currently as the welfare recipients. According to the results of in-depth interview and observation, the poverty of the observed has undergone the progress of trigger, worsening, breakup, desperation and stabilizing stages. The poverty factors found in this study could be categorized into two factors; circumstantial factors(bankruptcy after IMF, debt guarantee for relatives) and inner factors(the participants' behavior and characteristics). The circumstantial factors worked mainly in the trigger stage and the inner factors contributed to worsening economic crisis and facilitating the progress. According to the result, this study suggests not only individual-scale measures such as encouragement of familial bond or medical treatment of the alcoholism but also social measures including proper regulation of shark loan and opportunity supply to exit from poverty.

• Journal of Korean Medicine Rehabilitation
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• v.23 no.4
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• pp.59-71
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• 2013

Objectives The aim of this review is to figure out which acupoints are frequently used to treat low back pain and which exercises are effective to low back pain. Methods We searched the three electronic database (RISS, KISS, KTKP) and manually checked related Korean journals and reference lists up to June 2013. We investigated the frequency of acupoints for using treatment of low back pain. We Introduce exercise therapies we can do easily at home without professional skills for treatment low back pain. Results We included 72 articles in this study. The most frequently adopted acupoints were BL25, BL23, BL24, GB30, BL40, BL26, BL60, GB34, BL52, BL57, GB39. The most frequently adopted meridian pathways were BL, GB, GV, ST. The most frequently adopted disease causing low back pain were HIVD (Herniated intervertebral disc), Lumbar sprain, Spinal stenosis, Compression fracture, Cauda equina syndrome, Spondylolisthesis, Ankylosing spondylitis. There are many exercise therapies (Lumbar stabilizing exercise, Resistance exercise, Bareunmom physical exercise, Mckenzie exercise, Williams exercise, Emblass exercise, Swiss ball exercise, Thera band exercise, Yoga) for treatment low back pain. Conclusions These results suggest that most frequently adopted acupoints were foot taeyang urinary bladder channel acupoints. Beacuse foot taeyang urinary bladder channel is passes through the waist, it will be effective for treatment of low back pain. Also exercise therapy is effective for enhance Muscular strength. In order to treatment of low back pain, Acupuncture treatment is also important, as well as exercise therapy.

• The Journal of the Convergence on Culture Technology
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• v.6 no.3
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• pp.225-231
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• 2020

This study aims to examine the efficacy of online lectures conducted by most universities in 2020 in response to the Covid-19 crisis. Furthermore, this study analyzes students' opinions regarding online lectures, thereby assessing the possible direction that future online lectures could take. This study's results indicate that online lectures can have a positive effect on learners' reading comprehension. Also, student satisfaction with online lectures was found to be quite high. Among the reasons students cited for favoring the online format were: (1) the fun presentation of class information; (2) the diversity of subjects covered; and (3) the ease of using the Internet. Among the improvements made for enhancing online lectures were technical enhancements (such as fixing attendance check authentication errors) and stabilizing the playback of lecture videos. By way of concluding, this study claims that professors who are familiar with giving lectures in person should come to recognize that online lectures are not simply another option, but are essential for the future. As such, the academic community must focus on developing online content as a way to further higher education's development in meeting the academic demands of both the present and the future.

• Journal of the Korean Magnetics Society
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• v.3 no.2
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• pp.94-100
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• 1993

Electronic and magnetic properties of the novel rare-earth permanent magnet, $Sm_{2}Fe_{17}N_{3}$, are investigated by performing self-consistent local density functional electronic structure calculations. Employing the LMTO(Linearized Muffin-Tin Orbital) band method, we have obtained the electronic band structures for both paramag-netic and ferromagnetic phases of $Sm_{2}Fe_{17}N_{3}$. Based on the energy band structures, we have studied bonding ef-fects among Sm, Fe, and N atom as well as electronic and magnetic structures. It is found that the N atom sub-stantially reduces the magnetic moment of neighboring Fe atoms through the hybridization interaction and also plays a role in stabilizing the structure. the average magnetic moment of Fe atoms in the ferromagnetic phase of $Sm_{2}Fe_{17}N_{3}$ is estimated to be $2.33{\mu}_B$, which is ~8% larger than the magnetic moment of $Sm_{2}Fe_{17}$, $2.16{\mu}_B$. The Fe I (c) atom, which is located farthest from the N atom and surrounded by 12 Fe nearest neighbors, has the largest magnetic moment ($2.65{\mu}_B$), while the Fe III (f), whose hybridization interaction with N atom is very strong, has the smallest magnetic moment($1.96{\mu}_B$).