• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.6
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• pp.61-67
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• 2018

The face milling cutter, which is mainly used for the face milling, is used to cut the Carbon steel(SM20C) in the machining center for 5 times and 10 times respectively. This study clarify the dimensional accuracy characteristics according to the number of fine machining varied the condition of cutting depth, table feed speed and spindle speed. Cutting depth is varied 0.05~0.2mm, table feed speed is varied 0.05~0.2mm/min and spindle speed is varied 1500~2500rpm. As a result, the dimensional accuracy was stable 6 times machining with table feed speed 150mm/min and 10 times machining with table speed 100mm/min and cutting depth 0.05mm regardless times of machining.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.5
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• pp.122-130
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• 1996

In this study, machinability of some aluminum-magnesium alloy are experimentally investigated using polycrystalline diamond tool with turning, and evaluated some independent cutting variables affected micrometal cutting characteristics as cutting force, specific cutting resistance, shear angles. To know the effect of cutting parameters of single point diamond machining, experiments were performed to measure cutting forces for high speed turning of aluminum alloy 6061-T6, SM45C and FC20 with poly- crystalline diamond and coated cemented carbide tool. Independent cutting variables were changed to a variety of cutting speed, feed rate, rake angles, material properties of workpiece and tool. Futhermore. Some useful informations are obtained in this study can guide micro metal cutting of aluminum alloy with diamond tool.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.2
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• pp.461-472
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• 1996

The relationship between plastic deformation and crystal grain change in warm forging processes of SM10C carbon steel is studied. If the carbon steel is deformed at warm forging temperature(about recrystallization range), material properties are changed due to microstructural chanre of the crystal grain and cementite of the internal part. Some experimental values are investigated in terms of the elliptic degree of cementite, the grain size of cementite and ferrite grain size. When plastic deformation proceeds, the elliptic degree of cementite becomes larger and the grain size of cementite particle becomes small. In addition, the size of ferrite grain becomes fines by recrystallization. The elliptic degree of cementite has a considerable effect on formability. The distribution of effective strain in the forging was calculated by the rigid visco-plastic FEM analysis. The effective strain distribution obtained from the FEM simulation is compared with the experimental result, At the level of effective strain 0.3, dynamic recovery and dynamic recrystallization begin and at the level of over 2.5, the organization of material has better internal structure that is suitable for the following cold forming.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.2
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• pp.23-31
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• 2021

Surface texturing is a promising route to reduce the friction forces between two surfaces in sliding contact. To this end, the fabrication of micro dimples is one of the most widely used surface texturing methods. According to published results, textured surfaces with elliptical micro dimples offer the best friction performance. Therefore, we fabricated elliptical micro dimples on carbon steel (SM45C) by using dual frequency vibration assisted machining. High and low frequencies of 16.3 kHz and 230 Hz were applied to the 3D resonant elliptical vibrator. The 3D resonant elliptical vibrator with a triangular cubic boron nitride insert was assembled on a computer numerically controlled turning lathe. Oval micro dimples of various profiles were manufactured on carbon steel. In terms of the profile of the elliptical micro dimples, the experimental results indicated that the average micro dimple width and depth were 112 ㎛ and 7.7 ㎛. These dimensions are closely related to the cutting conditions and can be easily controlled.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.6
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• pp.10-16
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• 2021

Drilling is a crucial process that takes up a significant amount of weight during machining operations. In addition, drill tip-type tools and related operations have been developed for manufacturing industries to achieve economic efficiency. In this study, SM45C carbon steel, widely used for machine structures, was utilized as the working material after quenching and tempering. Insert-tip types of carbide tools, such as TiN and TiAlN, were used as tool materials. Drilling conditions such as the spindle revolution, feed rate, step of cut, and tool diameter were used to measure roughness, roundness, and straightness using the orthogonal array table statistical method. The surface roughness, roundness, and straightness characteristics based on the conditions were analyzed using ANOVA. The results showed that the spindle speed and feed rate were the main factors influencing carbide insert-tip drilling under the same conditions as the experimental conditions.

• Journal of the Korean Geotechnical Society
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• v.33 no.1
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• pp.57-65
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• 2017

During a construction of embankment, sub base, or retaining wall backfill, the speedy measurement of water content is necessary. In this study, a test method for field determination of water content of soil by the calcium carbide gas pressure (speedy water content measurement method) was evaluated for its reliability and accuracy. Dry oven and microwave oven methods were also used for water content measurement. In the test, weathered granite and Nakdong River sand in the site and kaolinite were used for water content measurement. The mass of 20, 22, 24, 26, 28, and 30 g of soil was respectively tested for 1, 3, and 5 min. The effect of each sample on water content was compared one another and analyzed. As the mass and testing time increased, the water content increased. The amount of soil was more important factor than testing time for the speedy water content measurement. In order to obtain similar result to that of dry oven method, 3 min of testing time with 24 g of soil was necessary for weathered granite classified as SM and 3 min with 30 g for Nakdong River sand classified as SP. For Nakdong River sand with 20-50% of kaolinite, the water content by speedy measurement increased as the clay content increased.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.1
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• pp.121-128
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• 2014

Superfinishing is essential for mirror surfaces, because among mechanical components cylindrical workpieces such as spindles must maintain precision and reliability with respect to functional characteristics. However, research on standardization of polishing film application combination to obtain mirror surfaces is insufficient. Consequently, this has been a factor in rising costs of mechanical components. Therefore, in this study, experiments have been conducted to determine efficient polishing film application combination for mirror surfaces ranging from ductile materials such as SM45C, brass, aluminium 7075, and titanium to brittle materials such as $Al_20_3$, SiC, $Si_3N_4$, and $ZrO_2$. From the experimental results, efficient polishing film application combination for metallic materials and ceramic materials is confirmed.

• The Korean Journal of Zoology
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• v.37 no.1
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• pp.19-32
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• 1994

가장 효과적인 H-2b 항원에 대한 시험관내 항체 생산 조건을 찾기 위하여 근교계 생쥐인 C57BL/6BySnj의 비장세포를 UV로 불활성학 시킨 후 항원으로 사용하고, A/wySnJ$\times$Sm/J(ASmJF1, hybrid)의 비장세포를 항원 수용자 계통으로 하여 5-7일동안 배양기에서 항체 생산을 유도하였다. 본 실험에서 T 임파구 대식세포와 임파구 분화 촉진 인자인Concanavalin A Lipopolvsaccharide. Pokeweed mitogen 등을 사용하여 20가지 조건으로 실험을 수행하여, 항체 생성 여부는 보체 의존성 세포 장애 실험과 면역 효소법에 의해 조사하였다 그 결과 모든 조건에서 항체생산이 확인되었으며. 가장 좋은 시험관내 항체 생산 조건으로는 T 임파구와 대식세포를 함께 사용하여 면역시킨 것이 가장 효과적이었다. 이 방법을 이용하여 항체 생산을 유도한 후 5일째 면역된 비장세포를 Sp2/0-Ag 14와 세포 융합시켜 H-2b 마우스의 체포 표면 항원에 대한 단일군항체 생산을 시도하였다. 또한 생체내 면역 방법과 비교하기 위해 6주간 C57BL/6BySnJ의 비장세포를 복강내에 주사하여 같은 조건으로 세포융합을 시도하였다. 그 결과 H-2b 세포의 표면 항원에 대한 항체 생산을 하는 세포군은 시험관내 면역 방법에서 3개 생체내 면역 방법에서 4개부 확인되었다.

• Food Science and Preservation
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• v.8 no.3
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• pp.246-251
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• 2001

This study was conducted to investigate the change of qualities of peaches by different packing types and humidity during storage period. The weight loss ratios of 'Kulakatawase' and 'Mibaek' by non-packing were about 6.8% and 4.9% for 4 days storage at room temperature, respectively whereas, the peaches by packing with 30㎛ LDPE were less than 1% for 25 days storage at low temperature and high humidity(95 $\pm$3%). The firmness values of the peaches were not decreased during storage at low temperature compared to the firmness values of the peaches during storage at room temperature. Little difference of total acidity and soluble solids of the peaches was during storage at low temperature. The contents of fructose and glucose in peaches were increased slightly after storage for 25 days but that of sucrose was decreased slightly. When peaches were stored at low temperature(0∼2$\^{C}$) and high humidity(95$\pm$ 3%) after packing with 30㎛ LDPE or 25㎛ perforated polyolefin film 'Kurakatawase ' and 'Mibaek' were able to storage for 20 and 25days, respectively.

• Journal of Korean Society of Forest Science
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• v.84 no.2
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• pp.166-177
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• 1995

This study was carried out to discuss how soils in the area planned for a forest road construction can be mechanically tested and practically applied. For this, 16 soil test samples from 8 plots(2 samples per plot) were used. The major tests are focused on unit weight before and after cut, water content, liquid and plastic limits, sieve and hydrometer analysis etc. The total unit weight(${\rho}_t$) before and after cut are $1.69g/cm^3$ and $1.19g/cm^3$, respectively. Their water contents are 21.0% and 20.5%. The coefficient of uniformity U and coefficient of curvature C obtained from sieve and hydrometer analysis are 125 and 0.42, which mean generally not well graded. On the soil classification by USCS, SM(silty sand or silt-sand mixed soil)is a Key soil, but it seems to be not good for fill material. From the standard proctor test are resulted $1.40{\pm}0.065g/cm^3$ for the unit weight(${\rho}$) in the nature and $1.88{\pm}0.049g/cm^3$ for the optimum proctor unit weight(${\rho}pr$) each. With this to say, it is necessary more powerful compaction work at earth filling, with which this soil reachs enough the ${\rho}pr$, and more earth.