• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.8
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• pp.17-23
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• 1999

This paper presents the characteristics of the gas flow in the engine cylinder under various intake flow conditins. The particle tracking velovimetry(PTV) was used to anlayze the gas flow pattern and flow field in the cylinder. Effects of tumble intensifying valve(TIV), swirl intensifying valve(SIV) and one-valve deactivated condition on in-cylinder flow patterns were compared with the baseline engine udner 600rpm motoring condition. In addtion, tumbel ration was estimated rwith results of in -cylinder flow fields. Base on experimental results, the tumble ration of in-cylinder flow field has the maximum value at the bottom dead center for the different four inlet conditions. In TIV condition, the tumble ration is 1.35 times larger than that of baseline engine and 1 intake valve deactivated condition is effective to improve in-cylinder swirl motion.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.265-270
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• 1999

At this study, we investigated the chemical component and the mineral granular composition of sedimentary rock and others where were distributed in Taegu area and compared correlations with each data through the various physicla and mechanical characteristic test. As the result, d and E, they are kinds of granite, which contain much albite than others were proved to be strong by mechanical tests and the correlation moduli were proved to be more than 0.8 except P wave velocity-Poisson's ration relation when examined Elastic moduluous -Poisson's ration, P, wave velocity-Uniaxial compression strength, Elastic modulous -Uniaxial compression strength and Uniaxial compression strength-Poisson's ration correlation function graph.

• Journal of the Korean Vacuum Society
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• v.7 no.s1
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• pp.30-36
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• 1998

The plasma-spray technique is currently the most frequently used method to produce calcium phosphate coatings. Hydroxyapatite(HAp), one form of calcium phosphate, is preferred by its ability to form a direct bond with living bone, resulting in improvements of implant fixation and faster bone healing. Recently, concerns have been raised regarding the viable use and long-term stability of plasma-spray HAp coatings due to its nature of comparatively thick, porous, and poor bonding strength to metal implants. Thin layers (maximum of few microns) of calcium phosphate were formed by an e-beam evaporation with and without ion bombardments. The Ca/P ration of film was controlled by either using the evaporants having the different ration of Ca/P with addition of CaO, or adjusting the ion beam assist current. The Ca/P ration had great effects on the structure formation after heat treatment and the dissolution bahavior. The calcium phosphate films produced by IBAD exhibited high adhesion strength.

• Journal of Veterinary Clinics
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• v.15 no.1
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• pp.62-74
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• 1998

In feedlot cattle the abrupt change of diet from roughage to a large quantity of grain for the purpose to improve production often results in increased occurrence of rumen acidosis or acute carbohydrate encouragement enterotoxemia, bloats diarrhea liver abscess and laminitis or robot disease. The common management practice to control these problem is to increase the amount of concentrates in the diet in a stepwise manner until the animals are adapted to a high-grain ration. However this practice requires at least about 3 weeks adaptation period and specially prepared adaptation rations which contain various amount of concentrates. Present experiment was undertaken in order to findout the more simple and rapid adaptation method of cattle to a high grain ration. Nineteen Korean calves aging from four to six month were fed artifical hay (Youngchoun Chuk-Hyup, Korea) which contains 10% of concentrates or alfalfa and rye grass hays for two months and randomly alloted to three experimental groups and two control groups. The experimental group-1 was inoculated by stomach tube for two days with li500 ml/day of ruminal fluid fished from Korean beef cattle that had been previously adapted to a high-energy ration. The experimental group-2 was inoculated by trocalization for two days with the same ruminal fluid. The experimental group-3 was inoculated by trocalization with 1,500 ml/day of bacterial culture which contained 2$\times $10$^{9}$/m1 of Gram-negative bacteria derived from adapted luminal fluid. The two control groups were treated with normal saline solution by the same methods. All animals were fed high-energy ration that contained 80% of grain ad libitum for 30-74 days beginning on the third of the treatment. The effect of the inoculation on the adaptation was observed clinicopathologically with the following results; All of the experimental calves inoculated with the ruminal fluid or Gram-negative bacterial culture derived from adapted cattle did not show any signs of rumen acidosis or other related diseases, while most of the control calves did show diarrhea and bloat and a calf laminitis. The average daily weight gain and feed efficiency of experimental calves were slightly improved compared with control calves. Following the feeding of high-grain rational the pH of the ruminal fluid was lowered in both the experimental and control groups. However severe acidosis with the pH of below 5.0 was observed in only a control group-2. The protozoal number in ruminal fluid was markedly decreased during the high-grain feeding in both the experimental and control calves. However the decrease was mere severe in control calves compared with the experimental calves. The activation of the protozoa were completely disappeared within nine hours at the refrigerator temperature (4"C). No significant differences in heamatological and blood chemical values between the experimental and control calves were recognized. However in one control calf which showed clinically laminitis marked elevations of serum glutamic oxaloacetate transaminase and lactic dehydrogenase activities and a decrease of serum glucose level were observed. From these results it would be concluded the intraruminal transplantation of unadapted calves with the adapted ruminal fluid from cattle previously adapted to a high-energy ration prevents disease problem associated with high-grain feeding and improve weight gain and feed efficiency.ency.

• Journal of the Korean Society of Radiology
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• v.15 no.2
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• pp.117-123
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• 2021

This paper is to establish a basis for a dose reduction strategy by confirming correlations with the factors that may affect the radiation dose based on the dose records in low-dose chest CT and abdominal non-contrast CT. In order to find out the causes of unnecessary exposure, the correlation between seven factors (age, gender, height, weight, BMI, patient status [inpatient and outpatient], and use of dose modulation) and CT dose were identified. Logistic regression was used as the statistical analysis for correlation verification. In the low dose chest CT, as the higher values of height and BMI and dose modulation off were associated with lowering the risk exceeding Diagnostic Reference Levels(DRL) (odds ration<1, p<0.05). However, as woman compared to man and the higher values of weight were associated with highering the risk exceeding DRL (odds ration>1, p<0.05). In the abdomen CT, as dose modulation off were associated with lowering the risk exceeding DRL (odds ration<1, p<0.05). Therefore It is necessary to conduct research on the relationship between various factors affecting radiation exposure and patient radiation dose for reducing the dose.

• Korean Journal of Poultry Science
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• v.15 no.4
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• pp.269-275
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• 1988

The effect of mold inhibitor was determined in the commercial rations which had two different protein levels(18% and 12% ) and two different particle sizes(80% of the particles in the ration less than 1.19mm and 40% of the particles in the ration less than 1.1mm). After 40 days storage of the rations treated and not treated with the mold inhibitor the nutritional change of the experimental diets with 18% and 12% protein levels, the growth performance of chicks, and the weight of internal organs fed the 18% protein diet were observed as the criteria of this research The fat level and carotene content in the two diets with 18% and 12% protein level each were significantly (P＜0.05) decreased when the diets were not treated by the mold inhibitor. Even if mold inhibitor was mixed in the diet, the fat content in the diet which had 40% of the particles in the ration less than 1.19mm tended to be decreased, especially, in the diet with a 12% protein level. The carotene content in the diet treated with mold inhibitor which had 40% of the particles in the ration less than 1.19mm also tended to be decreased in both diets (18% protein and 12% protein). Feed types$\times$particle size interaction was significant for the fat content (P＜0.05) and for the carotene content (P＜0.05). The amount of crude protein and ADF was not significantly (P＞0.05) changed after 40 days storage. There was a significant decrease (P＜0.05) in total body weight gain and total feed intake observed in chicks fed the untreated diet with 40% of the particles in the ration less than 1.19mm. Feed conversion was significantly (P＜0.05) depressed in the chicks fed the untreated diet of both particle sizes. Particle size$\times$types of feed interaction in feed conversion was significant (P＜0.05). Relative sizes of the liver, pancreas and spleen were not affected significantly (P＞0.05) by the treatments.

• Korean Journal of Poultry Science
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• v.15 no.4
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• pp.261-268
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• 1988

The effect of two particle size ranges (80% of the particles in the ration less than 1.19mm ; and 40% of the particles in the ration less than 1.1mm) and two different levels of protein (18% and 12% ) on the activity of mold inhibitors in commercial ration was determined by measuring mold count, CO$30^{\circ}C$ production and aflatoxin concentration. A commercial fungistat was mixed in the treated diets at the level of 0.1% (W/W). Two types of experimental diets (18% & 12% protein) which contained 12.6 and 12.7% moisture content each were stored under the forced air humidifier at 85% humidity and a controlled-temperature of 29＋1$30^{\circ}C$ for 5 to 40 days. Mold count and CO$30^{\circ}C$ levels in the feed treated with mold inhibitor were significantly higher (P＜0.05 and P＜0.01 respectively) when 40% of the ration's particle size was<1.19mm. The different protein levels in the ration treated with mold inhibitor did not have a significant effect (P＞0.05) on the mold count and $CO_2$ production. Protein level $\times$ particle size range interaction on the $CO_2$ production was significant (P＜0.05). Aflatoxin production in the experimental diet with mold inhibitor was significantly (P＜0.05) affected by the levels of protein and the different particle size ranges. The interaction of protein levels and particle size ranges on the aflatoxin production was significant (P＜0.05) at 40 days of storage.

• The Journal of the Acoustical Society of Korea
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• v.17 no.4E
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• pp.41-47
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• 1998

Microphone is the first link in the speech recognition system. Depending on its type and mounting position, the microphone can significantly distort the spectrum and affect the performance of the speech recognition system. In this paper, characteristics of the speech signal for different microphones and microphone distances are investigated both in time and frequency domains. In the time domain analysis, the average signal-to-noise ration is measure ration is measured for the database we collected depending on the microphones and microphone distances. Mel-frequency spectral coefficients and mel-frequency cepstrum are computed to examine the spectral characteristics. Analysis results are discussed with our findings, and the result of recognition experiments is given.

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.3
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• pp.73-80
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• 1999

The objective of this study were to investigate the properties and to improve the disadvantages of the polymer concrete such as brittle fracture, large hardening shrinkage . In this paper, steel fiber reinforced polymer concrete is prepared with various steel fiber aspect ratios(ι/d), contents(vol.%), and their material characteristics were investigated experimentally . The aspect ration (ι/d) of the steel fiber was reversly proportional to slump value, and slump value tended to decrease as increase of steel fiber content . And harding shrinkage and impact resistance tended to be improved as the steel fiber content and aspect ration were increased.

• Journal of the Korean Home Economics Association
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• v.5 no.1
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• pp.794-814
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• 1966