• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.45-51
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• 2008

This paper presents theoretical and experimental analysis on the characteristics of the power spectrum of electormagnetic waves radiating from the spark plug and their cables of a distributorless ignition system. The theoretical study was conducted applying the microwave transmission line theory and the antenna theory. The experimental works were carried out to measure the standing wave ratio(SWR) and the radiation power spectrum of this system. As a result, it has been found that a spark plug and its cable is working as a monopole antenna radiating elelctromagnetic waves. Because of its similar structure to a monopole antenna, the envelope of radiation power spectrum distribution has a bell shape which can be obtained from a monopole antenna operating as a series resonant circuit. The frequency characteristics from the SWR measurements show a similar frequency characteristics of power spectrum of the system studied. Also, it has been found that the density of the power spectrum of the system fitting a long time used spark plug is higher than that of fitting a new spark plug.

• Ocean and Polar Research
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• v.32 no.2
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• pp.113-122
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• 2010

Understanding the abundance and distribution of massive jellyfish is necessary to forecast where or when their blooms will happen. The acoustic technique is one of the most useful methods of obtaining information if the acoustic characteristics of the targets are known. This study was conducted to determine the acoustic target strength (TS, dB) of two jellyfish species, Aurelia aurita and Cyanea nozakii, in the southern coast of Korea. For the ex situ measurements, 120, 200, and 420 kHz split beam transducers were used, and jellyfish with various bell lengths were arranged to prepare multiple jellyfish. Under 2 vertical individuals, the mean TS for multiple A. aurita at 120, 200, and 420 kHz was -72.7, -71.7, and -68.2 dB, respectively. In the case of 5 vertical individuals, the mean TS of the species was -71.3, -68.2, and -62.0 dB. Finally, the mean TS of C. nozakii at 120, 200, and 200 kHz was -62.0, -60.3, and -58.2 dB under 2 individuals and -58.1, -57.4, and -54.0 dB under 4 individuals, respectively. For both species, higher numbers of jellyfish resulted in a higher TS. In addition, higher frequencies were associated with a higher TS for the same jellyfish. These TS results for two species can be used as essential data for the acoustic detection of jellyfish in an open ocean or coastal area.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.4
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• pp.311-317
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• 2015

This paper describes how to apply one-dimensional simulation to predict unsteady state characteristics of the cold-gas pintle thruster. Mass flow rate, chamber pressure, and nozzle exit pressure are key parameters for thrust control. Chamber pressure rose and fell monotonously with the pintle stroke variation, while thrust variation was different from chamber pressure variation. During the forward pintle stroke operation, the thrust value tended to decrease initially and returned to increase when pintle speed and chamber free volume exceed some specified value. Even though one-dimensional simulation has the limitations to predict unsteady state characteristics, it is still useful for initial performance assessment of various thrusters which adopt an altitude compensation nozzle such as a dual-bell nozzle, prior to experiment or numerical analysis.

• Journal of Korean Physical Therapy Science
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• v.10 no.2
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• pp.96-103
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• 2003

The purpose of this study was to assess the effect of applied pressure to abdomen on lumbar and abdominal muscle activation during upper limb exercise. The experimental group consisted of twenty-seven healthy male subjects (mean age=$22.40{\pm}2.19years$, mean height=$175.30{\pm}2.19cm$, mean weight= $67.67{\pm}7.44kg$, RM=$8.43{\pm}2.76kg$). In each different pressure condition (OmmHg, 30mmHg, 70mmHg, 100mmHg), upper limb exercise was performed in total of 10 trials with 10 RM dumb-bell exercise. Lumbar and abdominal muscle activity was measured using surface bipolar electrode electromyography(EMG). EMG activity was measured from upper rectus abdominis, external oblique abdominis, internal oblique abdominis, and elector spinae. The raw EMG signal was processed into the root mean square(RMS). All RMS EMG data were normalized and express as a percentage of the EMG(%EMG). Collected data were statistically analyzed by SPSS/PC Ver 10.0 using two-way analysis of variance for repeated measures($4{\pm}3$) and Bonferroni post hoc, test. Lumbar and abdominal muscle activation was significantly increased when 100 mmHg was applied(p<.05). Upper rectus abdominis activation was significantly increased compared as other muscles activation(p<.05). However, there were no interaction between pressure and muscles(p>.05). The findings of this study can be used as a fundamental data when lumbar orthosis is applied and external pressure can be used as a therapeutic tool.

• Journal of the Korean Mathematical Society
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• v.45 no.3
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• pp.727-740
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• 2008

A ring R is called IFP, due to Bell, if ab=0 implies aRb=0 for $a,b{\in}R$. Huh et al. showed that the IFP condition need not be preserved by polynomial ring extensions. But it is shown that ${\sum}^n_{i=0}$ $E_{ai}E$ is a nonzero nilpotent ideal of E whenever R is an IFP ring and $0{\neq}f{\in}F$ is nilpotent, where E is a polynomial ring over R, F is a polynomial ring over E, and $a_i^{'s}$ are the coefficients of f. we shall use the term near IFP to denote such a ring as having place near at the IFPness. In the present note the structures of IFP rings and near-IFP rings are observed, extending the classes of them. IFP rings are NI (i.e., nilpotent elements form an ideal). It is shown that the near-IFPness and the NIness are distinct each other, and the relations among them and related conditions are examined.

• Microbiology and Biotechnology Letters
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• v.19 no.1
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• pp.31-36
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• 1991

A 7.5 kilobases hybrid plasmid, designated as pCE1301, was constructed by combining Eschurichia cwli plasmid pBELl which carries the kanamycin resistance gene of Tn5 with a cryptic plasmid, pSRl of Corynebacterium glutamicum. pCE1301 was transformed C. glutaicum by PEG-mediated protoplast method and its transformation efficiency was about $3.0\times 10^3$ transformants per $\mu g$ of the hybrid plasmid DNA. The physical map reveals that pCE1301 has single restriction sites for SalI and EcoRl, respectively. 'The kanamycin resistance of pCE1301 was stably maintained in C. glutamicum up to 25 generations and any segregation was not detected. pCI31301 was also introduced into Brevibacterium flavum and E coil, and replicated in those strains. pCE1301 was proved to be useiul in cloning the homoscrine dehydrogenase gene from C. glutamicum.

• Microbiology and Biotechnology Letters
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• v.19 no.1
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• pp.37-44
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• 1991

- I aimed to isolate trans-acting factors involved in the basal expression level of eukaryotic genes. One of the yeast histidine biosynthetic gene, HIS5 was taken as a model for this study. HIS5 gene has a substantial basal level in amino acid rich medium and is derepressed if starved for any single amino acid. The derepression is mediated by cis-acting DNA sequences 5'-TGACTC-3' found in 5' non-transcribed region of the gene and trans-acting factors including GCN4 as positive factor and its negative factor GCDI 7, and GCNZ as a negative factor of GCD17. I first investigated the role of these trans-acting factors in HIS5 basal expression level by using HIS5-pH05 fusion in which expression of pH05 gene encoding inorganic phosphate-repressible acid phosphatase (APase) is regulated by HIS5 promoter. Strain with gcn2 or gcn4 mutation showed 3 to 4 fold lower APase activity than wild type. The level of APase activity was similar in gcn2 and gcn4 mutants. Trans-acting factors involved in basal level were identified by isolating 14 mutants showing increased expression of HISSPH05 fusion from gcn4 background. All the mutants carry a single nuclear recessive mutation and fall into four complementation groups, designated as bell (basal expression level), be12, be23 and be14.

• Journal of the Korean Professional Engineers Association
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• v.24 no.6
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• pp.106-112
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• 1991

Electronics has different meanings to different people and in different countries. Hence, let me difine the term in the sense that it is used here. Electronics in the science and the technology of the passage of charged particles in a gas, in a vacumn, or in a semiconductor. The beginning of electronics came in 1895 when H. A. Lorentz postulated the existence of discrete charges called electrons. Two years later J.J. Thompson found these electrons experimentally. In the same year (1897) Braun built what was probaly the first electron tube, essentially a primitive cathode-ray tube. It was not until the start of the 20th century that electronics began to take technological shape. In 1904 Fleming invented the diode which he called a valve. This era begins with the invention of the transistor about 30 years ago. The history of this invention is interesting. M.J. Kelly, director of research(and later president of Bell Laboratories), had the foresight to realize that the telephone system needed electronic switching and better amplifiers. Vacuum tubes were not very reliable, principally because they generated a great deal of heat even when they were not being used, and, particularly, because filaments burned out and the tubes had to be replaced. In 1945 a solid-state physics group wa formed. The foregoing completes the history of electronics and electronic industries up to 1978. There is already a start toward a merging of the computer and the communication industries which might be called information manipulation. This includes storage of information, sorting, computation, information retrieval, and transmission of data. This combination of the computer and the communication fields will penetrate many disciplines. Applications will be made in the fields of law, medicine, biological sciences, engineering, library services publishing banking, reservation systems, management control, education, and defense.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.23 no.2
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• pp.174-185
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• 2010

Objective : In period of convalescence and aftereffect, facial palsy patients suffer from social and psychological problems, besides experiencing physical inconvenience. So Quality of life is important Evaluation in treatment or facial palsy. Nevertheless the aims of recent study were only trying to explain about objective symptoms. Therefore, Oriental-Western Medicine was performed, effectiveness of treatment were measured in Quality of life. Methods : Acute facial palsy patients who visiting whin 5days completed questionnaire about Quality of life, if he(or she) participated voluntarily. Questionnaire are comprised of general characteristics, Facial Disability Index(FDI), WHOQOL-BREF, VAS and House-Brackmann grade. Questionnaire used two times, the first medical examination and 4weeks later after starting Oriental-Western Medicine. The statistical analysis was performed by GraphPad Prism 4.0. T-test was used to verify effectiveness between the two groups. Results : 1. When we compared the first medical examination with 4weeks later, score of FDI-Physical function and FDI-Social/Well-bieng function increased but they were not valid statistically. 2. When we compared the first medical examination with 4weeks later, in WHOQOL-Brefoverall domain and physical domain, score increased. In WHOQOL-Bref-psychological, Social, Environment domain, score decreased. but, they were not valid statistically. 3. VAS, House-Brackmann grade decreased, but, they were not valid statistically. Conclusion : The number of subjects with facial palsy in our study(N=5) was too small, and the period of study(4 weeks) was short, too. For this reason, our data were not valid statistically. But Facial palsy Patient's Quality of life has risen.

• Journal of Acupuncture Research
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• v.19 no.5
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• pp.112-123
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• 2002

Background and Objective : The evaluation of facial nerve function is a complex procedure. The House-Brackmann facial nerve grading system(H-B grade)and the Yanagihara grading system(Y-system) have been recommended as universal standards for assessing the degree of facial nerve palsy. The purpose of this study is to compare the effectiveness of Y-system and H-B system and to know the advantages of each system for each stage of incomplete recovery or sequelae of facial paralysis. Materials and Methods : A comparison between H-B grade and Y-system was studied with 137 evaluations of 61 cases of incomplete recovery or sequelae of peripheral facial paralysis. Each case was graded by using H-B system as a gross system and Y-system as a regional system before treatment, after 12 weeks and 6 months Results and Conclusions : The range of score in the Y-system 0-6, 8-16, 14-22, 24-34, 32-38, 38-40 were matched with grade VI, V, IV, III, II and I in the H-B system. The percentage of H-B grade III was the greatest among 137 evaluations and y-system showed the greatest score range. H-B system is easy to use but Y-system is more objective, quantitative and convenient to use in the incomplete recovery or sequelae state.