• 한국안전학회지
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• 제13권4호
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• pp.79-86
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• 1998

The effect of specimen thickness on fatigue crack growth behavior has been carried out by compact tension specimens of thickness of 3mm, 10mm and 25mm for maraging steel and Al 7075-T6. The closure points were determined during the test by means of a clip-gage situated at the notch mouth. Specimen thickness have no apparent influence on the fatigue crack growth rate of maraging steel, but the crack growth rate of 25mm thickness specimen for Al 7075-T6 is faster than that of 3 and 10mm specimens. The difference of crack growth rates can be successfully explained by considering the different stress state of plane strain and plain stress due to the variation of specimen thickness. Also the crack opening ratio of 25mm specimen is greater than those of 3 and 10mm specimens. When a side groove is introduced in a 10mm specimen, the crack growth rate is approximately similar to that of 25mm specimen. The effective thickness expression of $B_e=B_o-(B_o-B_N)^2B_o$ is the most appropriate to evaluate the crack growth rate of side-grooved specimen. Fatigue crack growth rates can be well described by $\Delta K_{eff}$ of the crack closure points in regardless of all thickness and side-grooved specimens.

• 설비공학논문집
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• 제26권6호
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• pp.287-293
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• 2014

Internal combustion engines release 30~40% of the energy from fossil fuels into the atmosphere in the form of exhaust gases. By utilizing this waste heat, plenty of energy can be conserved in the auto industry. Thermoelectric generation is one way of transforming the energy from engine's exhaust gases into electricity in a vehicle. The thermoelectric generators located on the exhaust pipe have been developed for vehicle applications. Different experiments with thermoelectric generators have been conducted under various test conditions as following examples: hot gas temperature, hot gas mass flow rate, coolant temperature, and coolant mass flow rate. The experimental results have shown that the generated electrical power increases significantly with the temperature difference between the hot and the cold side of the thermoelectric generator and the gas flow rate of the hot-side heat exchanger. In addition, the gas temperature of the hot-side heat exchanger decreases with the length of the thermoelectric generator, especially at a low gas flow rate.

• 대한치과교정학회지
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• 제19권2호
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• pp.25-34
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• 1989

This experiment was performed to study the effect of prostaglandin $E_2$ on tooth movement and root resorption in orthodontically treated cats. Twenty five cats were divided into five groups and closed coil springs delivered 80gm were stretched between upper canine and 3rd premolar. $10{\mu}g$ of $PGE_2$ was injected locally in the submucosal area of the upper right canine, while the left side served as a control and was injected saline 0.1ml. The distance between canine tip and central cusp tip of the 3rd premolar was measured. Scanning electron photomicrographs were made of the coronal half of the distal root surface of canines and cemental craterings were observed and quantified using point-counting volumetry. Data were analyzed by 2-way ANOVA and paired t-test. The results were as follows: 1. The rate of tooth movement of the $PGE_2$ side was increased, particularly at 1 day, compared with the control side. 2. The rate of tooth movement was minimum from 7 days to 10 days. 3. The resorption of root surface of the $PGE_2$ side was decreased from 4 days to 10 days, compared with the control side.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.547-552
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• 2003

In mold machining, there are many concave machining regions where chatter and tool deflection occur since MRR (material removal rate) increases as curvature increases even though cutting speed and depth of cut are constant. Boolean operation between stock and tool model is widely used to compute MRR in NC milling simulation. In finish cutting, the side step is reduced to about 0.3mm and tool path length is sometimes over 300m. so Boolean operation takes long computation time and includes much error if the resolution of stock and tool model is larger than the side step. In this paper, curvature of CL(cutter location) surface and side step of tool path is used to compute the feedrate for constant MRR machining. The data structure of CL surface is Z-map generated from NC tool path. The algorithm to get local curvature from discrete data was developed and applied to compute local curvature of CL surface. The side step of tool path was computed by point density map which includes cutter location point density at each grid element. The feedrate computed from curvature and side step is inserted to new tool path to regulate MRR. The resultants wire applied to feedrate optimization system which generates new tool path with feedrate from NC codes for finish cutting. The system was applied to speaker mold machining. The finishing time was reduced to 12.6%. tool wear was reduced from 2mm to 1.1mm and chatter marks and over cut on corner were removed.

• Journal of Chest Surgery
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• 제27권2호
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• pp.148-152
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• 1994

We have experienced 21 cases of traumatic diaphragm injury between October, 1989 and September, 1993. Of these patients, 17 cases were caused by blunt trauma and 4 by penetrating injury. Among 17 blunt traumas, 10 cases developed at left side, 6 at right and 1 at central subpericardial diaphragm, and among penetrating injuries, 3 cases developed at right side and 1 at left. Overall mortality rate was 21% and one due to blunt trauma was 29%. Initial hypotension was a predisposing factor to presume future death. When associated injuries involved 4 or more organs, mortality rate was high.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 추계학술발표회논문집(1)
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• pp.295-300
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• 1996

To investigate the effects of the side-orifice on the pressure drop for single-phase flow, a series of experiments have been carried out with 16 different downstream test sections with various combinations of side-orifice shapes, different numbers of side-orifices, and different arrangements of the side-orifice using water as a working fluid. From the measurements of the pressure drop and the flow rate, the pressure loss coefficient of the side-orifice(s) has been evaluated. Based on the total number of 529 present data, an empirical correlation for the pressure loss coefficient has been developed in terms of Reynolds number and geometric parameters, such as area ratio, equivalent diameter, leading edge, and average width of side-orifice.

• 한국생활과학회지
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• 제12권5호
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• pp.767-776
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• 2003

The purpose of this study was to classify side somatotypes of the trunk by analysing photographic data. Then their distribution according to the age groups was studied. The subjects were 315 females of 18 to 49 year-old. Thirty one photographic measurements were taken to each subject. The factors affecting the side somatotype of the trunk were obtained by principal component analysis, vertical size, posterior/anterior depth and neck posture. The side somatotypes of the trunk were classified into 4 types and their differences were shown by analysing photographic data. The side silhouettes of 4 types were compared with balanced type. By suggesting the canonical discriminant function with the unstandardized canonical coefficient, individual somatotype of the trunk could be discriminated from the photographic data of anterior neck height, anterior waist height, posterior waist depth, buttock height, and anterior depth at the level of back protrusion. The frequency distribution of the side somatotypes of the trunk according to the age groups could be applied for clothing construction and the rate of clothing production.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.987-992
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• 1997

Burrs always come out with the machining of ducterial with small size. Though the size of burrs is small, burrs dominate deterioration of the accuracy of the micro grooves. So the burr generation model especially side burr generation model was investigated to predict the size of the burrs at the given cutting conditions. The side shear plane is introduced to build the burr generation model and the width of side shear plane nomalized with cutting depth is defined with the shear angle. From the theoretical observation, the width of side shear plane can vary up 40% of the cutting depth. To determine the size of burr and stiffness, single groovings were carried out and it was found that there exist a critical depth of cut that the size or stiffness of the burr vary.

• 한국통신학회논문지
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• 제35권2C호
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• pp.172-181
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• 2010

본 논문은 분산 비디오 코딩을 위한 적응적 블록 양자화 기법을 제안한다. 제안하는 방법에서는 분산 비디오 복호기에서 보조정보 프레임을 생성하면서 예측된 움직임 벡터를 부호기에 보내줌으로써, 부호기는 큰 복잡도의 증가 없이 보조정보 프레임을 완벽하게 복원한다. 또한, 이렇게 복원된 보조정보 프레임과 원본 프레임의 차이를 적응적으로 블록별 양자화를 수행한다. 제안한 방법은 오류 발생 비율을 이용하여, 교차 확률에 따라 적응적으로 부호화함으로써 부호화 비트를 감소시킬 수 있는 특징이 있다. 제안한 방법은 부호기에서 교차 확률 및 교차된 비트의 위치를 알 수 있기 때문에, 채널 복호기의 오류 수정 능력에 맞추어 패리티 비트를 전송하여 낭비되는 비트의 양을 감소시킬 수 있다. 컴퓨터 시뮬레이션을 통하여 제안한 방법이 기존의 방법 대비 66% 비트율 감소를 얻었으며, 기존의 DVC 피드백 채널에 따른 지연을 대폭 감소시켰다.

• 한국안전학회지
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• 제21권5호
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• pp.46-52
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• 2006

The purpose of this paper is to investigate the removal efficiency of fine dusts as the configuration condition of machinery and equipments in Clean Room and to analyze the flowing behaviors of fine dusts as the layout of Clean Room. The layout of the Clean Room was classified into side layout type, 2 center line type and center concentration type layout, and the flow rates used in this research were 0.22m/s, 0.44m/s and 0.80m/s. Dust removal efficiency as layout change was decreased 37% for side layout type, 31% for 2 center line type and 20% for center concentration type layout at the flow rate of 0.22m/s, compared with the state without machinery and equipments in Clean Room. The efficiency was decreased 42% for side layout type, 22% for 2 center line type and 8% for center concentration type layout at the flow rate of 0.44m/s, and decreased 20% for side layout type, 18% for 2 center line type and 10% for center concentration type layout at the flow rate of 0.80m/s. According to the result of dust removal behavior, $0.3{\mu}m,\;1{\mu}m\;and\;3{\mu}m$ dust except for $5{\mu}m$ showed the higher change of the behavior in side layout type than in center concentration type layout due to the change of air flow. It was confirmed that removal behavior depends on the layout of machinery and equipments as the dust size decreases.