• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1479-1486
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• 2000

This paper introduces the improved moving frame acoustic holography (MFAH) method and its application. MFAH allows us to visualize the noise generated by moving noise sources by employing a vertical line array of microphones affixed to the ground. The sound field generated by moving sources is different from that of stationary ones due to the movement of the sources. Therefore the measured sound pressure by the microphone on the ground has to be processed so that it cooperates the effect of the movement. This paper discusses the effect of moving noise sources on the obtained hologram by MFAH. This assures the applicability of MFAH to the visualization of moving sources. This paper also reviews the improved MFAH that can visualize a coherent narrow band noise and a pass-by noise. The practical applicability of the improved MFAH was demonstrated by visualizing tire noise during a pass-by test.

• Journal of Power Electronics
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• 제11권6호
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• pp.811-818
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• 2011

Modulation strategies for multilevel inverters have typically focused on synthesizing a desired set of sinusoidal voltage waveforms using a fixed number of dc voltage sources. This makes the average power drawn from different dc voltage sources unequal and time varying. Therefore, the dc voltage sources are unregulated and require that corrective control action be incorporated. In this paper, first two new selections are proposed for determining the dc voltage sources values for asymmetric cascaded multilevel inverters. Then two modulation strategies are proposed for the dc power balancing of these types of multilevel inverters. Using the charge balance control methods, the power drawn from all of the dc sources are balanced except for the dc source used in the first H-bridge. The proposed control methods are validated by simulation and experimental results on a single-phase 21-level inverter.

• 한국식품영양과학회지
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• 제22권6호
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• pp.792-796
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• 1993

The synthesis alcohol-oxidase[EC 1.1.3.13] was investigated in the yeasts, Candida boidinii CBS 8106 and C. boidinii CBS 2428, during growth on different carbon sources. Alcohol-oxidase was undetectable in all strains submitted to the test in the mineral salts medium containing 1.0% glucose, but its production was rapidly increased when the carbon source was changed glucose to 1.0% methanol after 24hrs of incubation. When cells were grown on the various carbon sources (glucose, xylose, lactose, glycerol, galactose, saccharose, sorbose, lactic acid or acetic acid), the alcohol-oxidase activity was undetected. These carbon sources together with methanol yielded far better synthesis of alcohol-oxidase than in the case of carbon sources alone. Alcohol-oxidase was active towards alcohol of shorter alkyl-chain length than C5 and unsaturated alcohols. Its affinity for these alcohols decreased with the increasing length of the alkyl-chain. The apparent Km values for the methanol of Candida boidinii CBS 8106 and C. boidinii CBS 2428 were 1.96 and 1.21, respestively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1879-1881
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• 2003

In this paper, acoustic signals in $SF_6$ gas were analyzed using wavelet transform. For this, the PD sources in the $SF_6$ gas were divided into corona discharge surface discharge void discharge and crossing particle and acoustic signals were used to detect the PD sources. The measured signals were time-frequency distribution by wavelet transform and the features were extracted from the PD sources. As a result the characteristics of the PD sources were different. And this results is going to be used for basis diagnosis of $SF_6$ gas insulated apparatus.

• 기술혁신연구
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• 제13권3호
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• pp.27-49
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• 2005

In this Paper, we analyzed the relative importance of multiple sources and their effects on innovative activities. Through factor analysis, we found 5 sources of innovative activities; university/laboratory source, within firm source, general information source, vertical/competitive relation source, and horizontal relation source. Through regression analysis, we found that (1) 'within firm source' is the most important source on innovative activities, (2) from inputs' point of view, the more 'vertical/competitive relation source' is, the less innovative activities we, (3) from outputs' point of view, innovations are more activated when 'university/laboratory source' is abundant. but, they are less activated when 'general information source' and 'vertical/competitive relation source' is abundant, and (4) according to firm size and innovation stages(newproduct innovation, upgraded product innovation, and process innovation), the effect of sources on innovative activities is different.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1996년도 추계학술대회논문집; 한국과학기술회관, 8 Nov. 1996
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• pp.91-97
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• 1996

We have all heard sounds that did not sound "right" while riding in an automobile. Objectionable sounds are difficult to find and understand because the sound field is complex and dynamic in the near field of an automobile. Many different noise sources and transmission paths must be understood before an engineering change can be recommended. This paper reviews the fundamental characterization of sound and chscusses the Sound Intensity measurement technique. Sound intensity measurements locate sources and sinks of acoustic energy. Used with narrowband analysis equipment, acoustic noise sources can be identified. Sound intensity measurements are made -in-situ and do not require specmi anechoic facilities. The measurement results in a vector representation of the near field sound field and can discriminate between multiple sound sources.d sources.

• Journal of Nutrition and Health
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• 제29권5호
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• pp.480-488
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• 1996

This study was performed to investigate the effect of various types of calcium sources on calcium and bone metabolism. Sprague-Dawley male rats weighing approximately 89.3g were divided into 4 groups and fed experimental diets containing 0.5% calcium for 5 weeks. Four different calcium salts were used for the study : calcium phosphate, calcium lactate, calcium gluconate, and calcium carbonate. Food intake showed no significant difference n accordance with the type of calcium salt, but bo요 weight gain and food efficiency were lower in calcium gluconate and calcium carbonate groups. There was significant differences in liver, thymus and epididymal fat pad weight with the of calcium salt ; the calcium gluconate group showed lower values compared to the other groups. Femur and scapular length were higher in calcium lactate and calcium carbonate groups. Wet weight, dry weight, and density of the femur tended to be lower in the calcium gluconate group than the other groups, but this difference was not statistically significant. The calcium content of the other groups. The calcium gluconate group showed higher urinary calcium and lower calcium absorption and balance. In conclusion, calcium and bone metabolism were different according to the type of calcium sources consumed.

• 대한산업공학회지
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• 제32권3호
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• pp.236-241
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• 2006

Monitor height is one of the key factors in the VDT workstation design. Most of the previous studies have focused on traditional VDT workplace where the operators performed data entry or word processing tasks using single monitor. This study aimed to suggest proper monitor height when the main task was monitoring information from different number of information sources. Twelve male students participated in three experiments: single information source (one monitor), two information sources (one monitor and one CCTV), and three information sources (one monitor, one CCTV and a window). Subjects performed monitoring tasks for 10 minutes with 3 different monitor center heights : 89.0 cm (Low), 111.3 cm (Middle), and 124.8 cm (High). Surface EMG signals of five neck muscles, subjective discomfort ratings, preference, and working postures were recorded. Results indicated that the middle height was proper for one monitor condition, but the low monitor height was recommended for more than two information sources.

• 한국가금학회:학술대회논문집
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• 한국가금학회 1999년도 제16차 정기총회및학술발표회
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• pp.11-33
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• 1999

This study was conducted to determine the embryonic stages for the isolation of the highest number of PGCs and to improve PGCs enrichment method. The primordial germ cells(PGCs) from different sources of chick embryos were isolated. The embryonic stage having the highest number of PGCs from each sources was selected ; 1-day-old embryos for germinal crescent (stage 6-8), 2.5-day-old embryos for blood (stage 17-18) and 5.5-day-old embryos for gonad (stage 27-28). The number of PGCs from one embryonic germinal crescent, blood and gonad was about 87$\pm$1.8, 103$\pm$4.0, and 932$\pm$10.9, respectively. The viability of PGCs after Ficoll from each sources was similar, showing approximately 70%. the PGCs enrichment method was improved using Ficoll density gradient centrifugation. After this step the purity of PGCs from germinal crescent, blood, and gonad was 45$\pm$9.10%, 85$\pm$1.18%, and 86$\pm$0.19%, respectively. Also, PGCs were picked up by mouth pipette to improve the purity. This improved method for the separation of PGCs from different sources will serve as a useful too to preserve the foundation stocks of poultry and to produce germline chimeras.

• Journal of Plant Biology
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• 제7권1호
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• pp.11-14
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• 1964

Change of the amount of carbohydrates in relations with nitrogen metabolism was studied under the different manners of supply and with different sources of nitrogen. In barley plant supplied with nitrogen through root, the depression periods of glucose and sucrose content occurred at 2 days after, but the amounts of both sugars were different with the different sources of nitrogen; there were in sequence diminished by treatment of NO3, NH4 and urea. In sunflower leaves sprayed with urea both sugar contents were inversely related to the urea concentration sprayed, and depressing periods of the sugars appeared immediately in the N-deficient plant but late in the N-abundant one.