• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.107-112
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• 2003

The recent machine tools are requested so high-quality processing and productivity increasing. Therefore, it is so necessary to develop technology for high-speed and high-precision. This thesis touches on the development of high speed and intellectual line center. At first, the line center is necessary that strong structure, compact structure and light weight design for high-speed processing and transfer. So, it is necessary that examination of new materials and structures for light-weight and control devices for precision processing. So, it is going to make mention of the process of 1st model production for the above-mentioned based on test model production and evaluation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.527-530
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• 1995

In this paper, traffic modeling and control design was considered to analyze and improve the stability of train diagram in the open-loop Metro line. A complete discrete-event traffic model describing the natural instability of open-loop metro line is analyzed. The traffic stability properties are introduced and easy-to-implement state feed back traffic control algorithms are designed, which satisfied with system stability.

• ETRI Journal
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• 제32권3호
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• pp.475-478
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• 2010

A multiband meandered monopole antenna is proposed for digital video broadcasting handheld (DVB-H), global positioning system, personal communications service, wireless broadband (Wibro), and wireless local area network (WLAN) applications. The proposed antenna consists of a meandered line, a shorted length strip line, and a conductor strip between a meandered line and a microstrip feed line. By tuning a short strip and a conductor, a multiband impedance matching is achieved. The proposed antenna has an omnidirectional radiation and yields an antenna gain of greater than -3 dBi in the DVB-H band and 4.5 dBi in the Wibro and WLAN bands. Details of the proposed antenna design and experimental results are presented.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.445-456
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• 2010

Massive underground excavation can be carried out recently due to the technical development of the excavation for retaining wall. Feed-back analysis using field measurement results is recommended to secure the stability of the construction because calculated values at stages of the design and the construction are uncertain. Reinforcement plan should be established based on the result of it. This study deals with the underground excavation site, which is under construction and is close to structure(subway) at downtown area. The result of feed-back analysis on the measurement data of displacement at multi-soil layers was reflected to make a plan for safe construction. This case study can be useful information for contingency plan on abnormal displacement which can be occurred at similar underground excavation.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.239-244
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• 1999

Radial immersion ratio is an important factor to determine the threshold in face milling and should be estimated in process for automatic force regulation. In this paper, presented is a method of on-line estimation of radial immersion ratio using cutting force. When a tooth finishes sweeping, sudden drop of cutting forces occurs. These force drops are equal to the cutting forces that act on a single tooth at the swept angle of cut and can be acquired from cutting force signals in feed and cross-feed directions. The ratio of cutting forces in feed and cross-feed directions acting on the single tooth at the swept angle of cut is a function of the swept angle of cut and the ratio of radial to tangential cutting force. In the research, it is found that the ratio of radial to tangential cutting force is not affected by cutting conditions and axial rake angle. Therefore, the ratio of radial to tangential cutting force determined by just one preliminary experiment can be used regardless of the cutting conditions. Using the measured cutting forces and predetermined ratio, the redial immersion ratio is estimated. various experiments show that the radial immersion ratio can be estimated by the proposed method very well.

• 한국전자파학회논문지
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• 제13권10호
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• pp.1034-1039
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• 2002

본 논문에서는 개구결합 급전(포트 1)과 3차원 마이크로스트립 급전(포트 2)을 이용하여 단자간의 분리도가 우수한 이중편파 사각형 마이크로스트립 패치 안테나를 설계하였다. 설계는 각각의 급전방식에서 상용프로그램인 IE3D를 이용한 모의실험을 통하여 파라미터값들의 최적값을 찾고, 그 각각의 최적값을 통합하여 이중편파 마이크로스트립 안테나를 설계하고 제작하였다. 2 GHz 대역에서 실험한 결과 반사손실 10 dB 주파수 대역폭이 17 %이며, 30 dB 이상의 분리도를 확인하였다.

• 한국위성정보통신학회논문지
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• 제1권1호
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• pp.54-58
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• 2006

동작주파수를 쉽게 조절할 수 있는 신호생성용 안테나 (Antenna-Integrated Oscillator) 설계방법을 소개한다. 제안하는 회로는 광대역에서 부성저항을 갖는 능동회로 (Negative-Resistance Circuit)와 패치안테나로 구분되며, 오실레이터의 동작주파수는 안테나의 공진 주파수로 결정된다. 이러한 디자인 방법은 안테나와 오실레이터의 동작주파수 불일치로 인한 출력파워의 감소 가능성을 줄일 수 있다. 또, 제안하는 설계방법에서 안테나의 Feed 지점과 Feed 라인의 길이를 조절하여 최적의 출력파워를 낼 수 있음을 Load-Pull 시뮬레이션으로 확인하였다. C-band, X-band 회로를 각각 제작, 측정하였고 이를 통하여 설계방법의 타당성을 증명하였다.

• Membrane and Water Treatment
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• 제8권2호
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• pp.125-136
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• 2017

Reverse osmosis technology is being used on large scale for treatment of ground water, brackish water, wastewater and sea water. The most challenging issue in RO process is carbonate scaling which is directly linked with the efficiency and economy. Considering the natural phenomena of carbonate scaling different adaptations have been made to control scaling on the surface of RO membrane including acid dosage and antiscalant addition. As carbonate scaling is directly related with pH level of feed water, present study describes an experimental approach to reduce scaling on RO membrane by lowering the feed water pH by purging $CO_2$. In this comparative study four different conditions including control process (without any scale inhibitor), with dosage of antiscalant, with purging of $CO_2$ and with co addition of antiscalant and $CO_2$ in a feed stream line; it was established that $CO_2$ is a better appliance to reduce carbonate scaling on the membrane surface by reduce pH of feed stream. It was also observed that $CO_2$ and antiscalant mutually function better for scale control.

• 한국항행학회논문지
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• 제24권6호
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• pp.581-586
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• 2020

본 논문에서는 수평 슬릿이 추가된 지상파 디지털 TV(DTV) 및 UHD TV용 광대역 루프 안테나의 설계 절차와 방법을 제안하였다. 제안된 루프 안테나는 정사각형 루프와 두 개의 원형 섹터로 구성되는 기존의 광대역 루프 안테나에 소형화하기 위해 두 개의 원형 섹터에 수평 슬릿을 추가하였다. 급전을 위해 아래쪽 원형 섹터의 중앙에 동일면 도파관(CPW; coplanar waveguide) 전송선로가 삽입되었다. CPW 급전선로는 DTV 및 UHD TV 응용을 위해 75 옴 포트 임피던스를 사용하여 설계되었으며, 임피던스 정합을 개선하기 위해 중심신호선의 끝이 점점 가늘어지게 설계되었다. 최종 설계된 안테나는 두께가 0.8 mm인 FR4 기판에 제작하였다. 특성 실험 결과, 전압 정재파비(VSWR; voltage standing wave) < 2인 대역이 444.3-820.1 MHz로 DTV 대역(470-698 MHz)과 UHD TV 대역(698-771 MHz)에서 동작하는 것을 확인하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제16권1호
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• pp.57-62
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• 2003

An effort was made to assess comparative production performance in broiler chickens fed diets containing solvent extracted cottonseed meal (CSM) processed from BT and Parental Non-BT lines. Processed meal of national check and commercial produce cottonseeds were also used for comparison. The free gossypol contents were 0.02, 0.02, 0.44 and 0.03% in meals of BT, Parental Non-BT, national check and commercial produce cottonseeds, respectively. Day-old broiler chicks (n=243) were divided to 27 groups of 9 each. Nine dietary treatments (iso-nitrogenous, 23% CP and iso-caloric, 2,800 kcal ME/kg) were formulated viz., D1 (control, soybean meal-SBM based), D2 and D3 (BT CSM at 10% of diet with and without additional iron), D4 and D5 (non-BT CSM with and without additional iron), D6 and D7 (national check CSM with or without additional iron), and D8 and D9 (commercial produce CSM with or without additional iron at 2 ppm for every 1 ppm of free gossypol, respectively). Each dietary treatment was offered to three replicated groups up to 6 weeks of age. At the end of 6 weeks of age, 10 birds were taken out randomly from each treatment and were sacrificed to study carcass traits, organs' yield and histo-pathological changes in vital organs. The broiler chickens received CSM processed from BT (D2, 1,753 g and D3, 1,638 g) and Parental Non-BT (D4, 1,653 g and D5, 1,687 g) with or without additional Fe grew at same rate as observed in soybean meal (solvent ext.) based diet (D1, 1,676 g). The feed intake and feed conversion efficiency (feed: gain) in these dietary treatments (BT, non-BT line based diets) also did not differ significantly (p>0.05) from control diet. Similar observation was also observed in dietary treatments (D8 and D9) containing solvent extracted cottonseed meal of commercial produce origin. However, a decrease (p<0.05) in body weight gain and feed intake was observed in D6 containing national check CSM with high gossypol content. Addition of Fe in the diet (D7) improved (p<0.05) feed intake and weight gain but not to the extent as observed in diets containing BT, parental non-BT, and commercial produce CSM or control. However, any type of CSM did not affect feed conversion efficiency when fed with or without additional iron. The carcass characteristics in terms of dressing percentage, liver weight and heart weight was not significantly (p>0.05) different between the treatments. The eviscerated yields emanated from diets containing either BT, non-BT or commercial produce were statistically similar to control. However, eviscerated yield of broilers fed national check CSM with or without iron supplementation was lower (p<0.05) than BT cotton with Fe supplementation and commercial produce CSM. The study envisaged that BT, parental non-BT and commercial produce solvent extracted cottonseed meal can be included at 10% in soybean meal based broiler diet replacing soybean meal and rice bran without additional iron.