• Journal of the Korean Society for Precision Engineering
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• v.19 no.5
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• pp.133-138
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• 2002

The technique of high speed machining is widely studied in machining fields, because the high efficiency and accuracy in machining can be obtained in high speed machining. Unfortunately the development of tool fur high speed machining in not close behind that of machine tool. In this study, 10 types flat endmill is prepared for obtaining data according to tool shape. Especially, we concentrated in helix angle, number of cutting edge and rake angle. Cutting condition is selected for several experiments and measuring cutting farce, tool life, tool wear and chip shape according to cutting length. 3-axis cutting farces are acquired from the tool dynamometer with high natural frequency, as the conventional tool dynamometer (9257B, Kistler) has cannot measure the state of high frequency force. Particularly, we found out that the axial cutting force waveform has a good relation with tool wear features. And flow is interrupted at the beginning of cutting by the decrease of rake angle. By above results. it is suggested the endmill tool with 45$^{\circ}$helix angle, 6 cutting edge and -15$^{\circ}$rake angle is suitable for high speed machining.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.12
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• pp.27-35
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• 1999

In a typical spread spectrum system, parallel correlator occupies a large fraction of power consumption because of the large number of accumulators in the system. In this paper, a novel accumulator is proposed that can reduce the power consumption in the parallel correlator. The proposed accumulator counts the numbers of 1 of the incoming input data. The counted values are weighted and added together to obtain the final correlation value only at the end of the accumulation. The proposed accumulator has been designed and simulated by CADENCE Verilog-XL and synthesized by SYNOPSYS Design Compiler with $0.6{\mu}m$ standard cell library. Power consumption results have been obtained from EPIC PowerMill simulations. Simulation results are very encouraging. First, the power dissipation is reduced by 22% and the maximum operating frequency is increased by 323%. In addition, the parallel correlator using the proposed accumulators consumed less power than the conventional active parallel correlators by 22%, and less power than the conventional passive correlator by 43%.

• Human Ecology Research
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• v.56 no.4
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• pp.407-416
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• 2018

This study investigated the characteristics and changes of Jeongbang-village silk culture Jeollanam-do Province during Japanese Colonial Rule with a focus in on Gokseong-gun & Damyang-gun Jeongbang-village. The results of the study are as follows. First, after Japanese occupation, it changed from a traditional silkworm species, the Joseon Silkworms and the mulberry tree to an improved Japanese species. Japan established a silk spinning mill called Jongyeon Textile factory in Gwangju and Jeongbang Village was formed in poor rural areas. Second, the way of village management consisted of buying a large number of land for mulberry plans and creating mulberry fields as a cheap way to utilize the labor force for women and men in rural areas. Third, since the end of the Japanese colonial era, mulberry fields in Jeongbang villages which the Japanese left, were sold at a cheap price to Koreans. After the Korean War, the Korean government's efforts to modernize the silkworm industry resulted in a continuous plan to increase the number of silkworms. The impact of government policies has also increased the production of silkworms in these areas. However, since the early 1980s, Korean companies have been affected by Japanese economic policies and dumping by China that has resulted in in a sharp decline in their production. In the case of Gokseong-gun and Damyang, the production of silk products was halted and switched to other crops in the early 1990s when the farming industry began to decline.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.4
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• pp.397-402
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• 2013

In this study, we carried out the each lines of section, using GC (green silicon carbide) whetstone, the SCM415 material which separated by after and before heat treatments process, in 3+2 axis machining centers for integrated grinding after cutting end mill works, the spindle speed 8000 rpm and feed rate 150 mm/min. For the analysis of the centerline average roughness (Ra), we measured by 10 steps stages. Using Finite element analysis, we found the result of the load analysis effect of the assembly parts, when applied the 11 kg's load on both side of the ATC (Automatic tool change) arm. The result is as follows. For the centerline average roughness (Ra) in the non-heat treatment work pieces, are appeared the most favorable in the tenth section are $0.510{\mu}m$, that were shown in the near the straight line section which is the smallest deformation of curve. In addition, the bad surface roughness appears on the path is to long by changing angle, the more inclined depth of cut, because the chip discharging is not smoothly.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.5
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• pp.74-81
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• 2013

The high-speed machining in the manufacturing industry field has been widely applied for parts of vehicles, aircraft, ships, electronics, etc., recently, because the effect of cost savings for shortening processing time and improving productivity is great. The purpose in this study is to investigate the effect of cutting depth on the surface roughness of workpiece with the spindle rotational speed and feed rate of high-speed machines as a parameter to find the optimal depth in the finishing for ball end mill of the aluminum alloy 7075 which is used much in aircraft parts. When the cutting depth for the respective feed rate and spindle rotational speed is varied from 0.1 mm to 0.7 mm at intervals of 0.2 mm in the wet finishing of the aluminum alloy 7075 by the insoluble cutting oils and high-speed machining used in the rough machining of previous study, the surface roughness values and the cutting temperature are measured. In addition, the cutting surface shapes of test specimens are observed by optical microscope and compared with respectively. It is found that the surface roughness values and the temperature generated during machining are increased as the feed rate and cutting depth are raised, but those are decreased as the spindle rotational speed is increased.

• Journal of the Korean Wood Science and Technology
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• v.15 no.2
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• pp.53-66
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• 1987

Korean red pine (Pinus densiflora S. et. Z.) and pitch pine(Pinus rigida Mill) $5{\times}10cm$ dimension lumber were dried in a kiln providing a cross-circulation velocity of 5 m/sec at dry-and wet-bulb temperatures of 116 and $71^{\circ}C$, followed by 3 hours at 91 and $85^{\circ}C$. Compared to dimension lumber dried lumber were as follows. 1. To dry to 10 percent moisture content, the high-temperatures schedule of Korean red pine and pitch pine lumber took less than one seventh the time required by the conventional kiln drying schedule. 2. High-temperature drying rate and conventional drying rate to 10 percent moisture content of Korean red pine lumber were 2.75 and 0.35%/hr, and those of pitch pine lumber were 3.38 and 0.46%/hr respectively. 3. Compared to lumber of both species on conventional schedule, moisture gradient of high-temperature lumber was greater. 4. Compared to lumber on conventional schedule, maximum surface checking of high-temperature lumber of both species was severer, and maximum end checking of high-temperature lumber of both species was similar to that of lumber on conventional schedule. 5. Compard to lumber on conventional schedule, Korean red pine lumber dried at high temperature showed more honeycombing, but pitch pine lumber dried at high-temperature showed significantly slighter honeycombing. 6. Compared to lumber on conventional schedule, the high-temperature lumber showed less warping lumber of both species. 7. Collapse and casehardening of Korean red pine and pitch pine lumber on both scheules were slight.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.3
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• pp.56-62
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• 2022

The tank engine clutch flange constitutes a tank on which the engine and transmission of the tank are mounted. The engine clutch flange is fabricated using a difficult-to-cut material that exhibits high strength and hardness. It is difficult to process and requires considerable processing expertise. In addition, the engine clutch flange for the tank requires high machining precision because it is a system in which the connection is detachable. Because it requires high processing precision, the measurement of products equally important as processing. However, productivity is low owing to the significant amount of time required to measure each product using a three-dimensional coordinate measuring machine. Hence, this study is conducted to improve the productivity of the female tank engine clutch flange. Dedicated hobs and jigs are designed and manufactured to convert the existing end-mill cutting processing into hobbing cutting processing. An engine clutch for the tanks is manufactured using the manufactured dedicated hob and jig, and the shortening time is verified by measuring the processing time. In addition, a jig for inspection is designed and manufactured to measure the precision of the product. To verify the inspected product, the product precision is measured using a contact-type three-dimensional coordinate measuring machine and a surface roughness measuring instrument. The study confirmed that the productivity of the engine clutch flange product for tanks can be improved by simplifying the process, reducing the processing time, and simplifying product inspection.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2001.11a
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• pp.57-58
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• 2001

용수 다소비 산업으로 분류되는 제지공업의 특성 상, 용수사용의 억제 및 용수의 무방류화에 대한 압력이 증가되고 있는 반면, 초지환경은 날로 열악해지고 있는 실정이다. 한 예로써, 용지의 재활용율 및 재사용 비율이 증가함에 따라 원료의 저급화가 심 각한 수준에 이르고 있으며, 이러한 초지환경의 변화는 각질화되고 극도로 미세화된 다량의 미세섬유 발생 및 잡고지로부터 유입되는 점착성 이물질과 무기 충진제의 도입 등을 유발함으로서 제품의 물리적 성질 저하, 탈수부하 증가로 인한 생산성 저하, 약품사용량 증가 등을 초래하여, 결과적으로는 폐수처리장의 부하를 증대시킴과 동시에 청수사용량 및 폐수방류량을 증가시키는 악순환을 되풀이하게 된다. 국내 제지산업이 국제적 경쟁력을 갖추기 위해서는 제품의 증대가 필수적이나, 원료와 설비의존도를 감안할 때, 제품특성과 공정 분을 결정하는 습부공정을 정확히 파악하여 최적 운전조건을 확립하는 것이 가장 경제적이고 용이한 방법일 뿐만 아니라 전체 제지공정의 정정화에도 기여할 수 있을 것으로 판단된다. 일정규모이상의 종이를 생산하는 제지공장은 거의 대부분 컴퓨터로 처리되는 온라인 공정조절 시스템(On-line process control system)을 구비하고 료의 도입에서부터 설비운전 및 제품의 기본적인 품질관리까지 실시간의 자동화되고 안정적인 운전과 관리시스템을 유지하고 있다. 그러나 전체 제지공정 중, 제품 물성과 운전조건의 대부분을 결정하는 습부공정만큼은 아직도 주기적인 분석이 행해지고 있지 않을 뿐만 아니라, 슬러리의 농도나 보류도 정도를 제이하면 분석항목 조차도 변변히 확립되어 있지 않을 실정이다. 이는 다량의 물 속에 존재하게 되는 용전물질(Dissolved solids, DS), 부유물질(Suspended solids, SS), 섬 유(Fibers), 무기 미 세분(Inorganic f fines), 그리고 투입되는 약품간에 발생하는 계면동전현상 및 이러한 현상과 최종 지제 품의 물성간의 상관관계에 대한 이해 정도나 경험 부족에서 기인하는 것으로 생각된다. 1 1983년 미국제지기술연합회(T APpI)의 제지용 첨가제 분과위원회(Papermaking A Additive Committee)에서는 습부공정의 적절한 조절을 위해 어떤 항목들이 필요하며 그 중요도는 어떠한가를 조사하였으며, 그 결과로 전하밀도, 제타전위, 보류도 및 여수 도, 무기 미세분 함량 등이 중요하다고 보고하였다. 그러나 지료의 전기적 특성을 실시 간으로 측정하는 기자재류가 최근에 이르러서야 도입되고 있는 실정이기 때문에 충분 한 현장적용 사례가 보고되지 못하고 있으며, 결과적으로 얻어진 정보와 최종 지제품의 물성 및 초지기 운전조건과의 상관관계를 확립하는 작업결과는 더욱 찾아보기 어렵다. 따라서, 본 연구에서는, 라이너지 제조공장의 습부공정에 투입되는 약품이 지료 의 전기적 성질, 즉 전하밀도와 제타전위에 미치는 영향을 모니터링함으로서 지료의 전기적 성질들과 습부 공정상태와의 상관관계를 살펴보고자 하였다. 본 연구는 다음과 같은 순서로 진행하였다.

• Journal of Bio-Environment Control
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• v.12 no.4
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• pp.173-179
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• 2003

This study was established to control the overgrowth of cucumber and tomato plug seedlings by controlling of irradiation timings light intensities of red (R) light. Compared with the control, end-of-day (EOD) timing of R irradiation significantly reduced the seeding heights by 21.3% and 14.2% in cucumber and tomato, respectively. In addition, both plant seedlings treated with R light at EOD timing had the thickest stem diameter. Tomato seedlings treated with R light at EOD showed th highest chlorophyll content and the smallest leaf size. Dry weights of above ground plant tissue in both plant seedlings were significantly reduced by EOD R light treatment. And both plant seedlings treated with EOD treatment had the lowest T/R ratio, and the highest compactness rates. The increased intensities of R light resulted in the shorter plant heights in cucumber and tomato plant seedlings. It also reduced the length of hypocotyls and internodes and the size of leaves in the both seedlings. Elevated R light intensities tended to increase the stem diameter and chlorophyll contents. Dry weights of above ground plant tissue and roots in both plant seedlings were reduced by the elevated R irradiation. Cucumber seedlings treated with 2 and 8 $mol{\cdot}m^{-2}{\cdot}s^{-1}$ and tomato seedlings treated with 8 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ had significantly lower T/R ratio the other treatments tested.

• Journal of Bio-Environment Control
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• v.15 no.1
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• pp.69-77
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• 2006

The experiment was conducted to investigate the nutrition absorption pattern in the growth stage and develope the optimal nutrient solution hydroponically grown the cherry tomato 'Koko' in closed substrate culture system with the nutrient solution of National Horticultural Research Station in Japan into 1/2S, 1S, and 2S. When plant was grown in 1/2S, the growth and yield were high and the pH and EC in the root zone were stable. Suitable composition of nutrient solution for cherry tomato was $NO_3-N\;6.8,\;PO_4-P\;2.7,\;K 3.2,\;Ca\;3.6\;and\;Mg\;1.1\;me\;L^{-1}$ in the early growth stage, $NO_3-N\;7.3,\;PO_4-P\;2.2,\;K\;3.7,\;Ca\;3.6;and\;Mg\;1.1\;me\;L^{-1}$ in the late growth stage by calculating a rate of nutrient and water uptake. To estimate the suitability for the nutrient solution in a development of cherry tomato developed by Wongkwang university in Korea (WU), plant was grown in perlite substrate supplied with different solution and strengths(S) by research station for greenhouse vegetable and floriculture in the Netherlands (Proefstation voor tuinbouw onder glas th Mssldwijk; PTG) of 1/2S, 1S, and 2S, respectively. The growth was good at the PTG and WU 2S in the early stage and the PTG of 1S and WU of 1S and 2S in the late stage. The highest yield of cherry tomato obtained in the WU of 2S. pH and EC in root zone of WU of 2S were stable during the early and late growth stage. Therefore when cherry tomato plant was grown in WU of 2S of EC $1.6{\sim}2.0\;dS\;m^{-1}$in the nutrient solution, not only stable growth and yield but also fertilizer reduction can be obtained than that of PTG.