카리움을 含有한 니켈 觸媒에 있어서 싸이클로헥센의 脫水素化 反應에 관한 硏究

金京林,具憲書 연세대학교 대학원 1981 延世論叢 Vol.18 No.1

This study is concerned with Cyclohexane Dehydrogenation on Nickel catalysts and the promotion effect of Potassium on the reaction i9 studied in terms of Potassium content. Experimental results shelved that the catalyst containing K as K/K+ Ni=0.1675 ratio was the most effective on the removal of side reactions and on reaction promotion. On the Potassium-promoted Nickel catalyst, Cyclohexane Dehydrogenation was lst order reaction with respect to Cyclohexane concentration from 366 to 446℃ and the activation energy was 24.5kcal/gmol. There were no problems of fouling on the metallic nickel catalyst. Even though promoter was included, the fouling was serious on the Nickel oxide catalyst, but the fouling could be exterminated by feeding hydrogen.

DESIGN OF LOSSY INTERSTAGE NETWORK FOR BROADBAND MULTISTAGE MICROWAVE AMPLIFIERS CONSIDERING GAIN AND REFLECTION COEFFICIENTS

Kyung Heon Koo,Choong Woong Lee 대한전자공학회 1989 JTC-CSCC : Joint Technical Conference on Circuits Vol.- No.-

실 주파수 기법을 이용한 광대역 다단 마이크로파 증폭기 설계에 관한 연구

구경헌(Kyung Heon Koo),이충웅(Choong Woong Lee) 대한전자공학회 1986 대한전자공학회 학술대회 Vol.1986 No.12

기반 기술 : 6.0~18.0 GHz 주파수용 광대역 DFD 위상 상관기 설계 및 제작

최원 ( Won Choi ),구경헌 ( Kyung Heon Koo ),최원 ( Won Choi ),구경헌 ( Kyung Heon Koo ) 한국항행학회 2014 韓國航行學會論文誌 Vol.18 No.4

본 논문은 6.0 ~ 18.0 GHz 대역에서 동작하는 광대역 디지털 주파수 변별기(DFD, digital frequency discriminator)의 위상 상관기(phase correlator)를 설계하고 제작하였으며, 제작된 DFD 위상 상관기의 I와 Q 신호를 측정하고, 주파수 변별 오차를 분석하였다. 믹서형 위상 상관기의 동작 특성에 대한 해석적 관계식을 유도하였으며, 위상 상관기에 포함되는 IQ 믹서(mixer)와 8-way 전력분배기(power divider)는 RF 시뮬레이션 툴(tool)을 이용하여 모델링하였다. 설계된 위상 상관기는 제작되어 측정하였다. 제작된 위상 상관기의 I와 Q 출력신호를 측정하여 제시하였으며, 측정된 I와 Q 출력신호를 이용하여 위상오차(phase error)와 주파수 변별 오차(frequency discrimination error)를 나타내었다. 위상 상관기의 평균 위상오차(phase error)는 4.81°, RMS(root mean square)이고, 주파수 변별 오차는 1.49 MHz, RMS 이다. This paper has presented the design and fabrication of phase correlator for wideband digital frequency discriminator (DFD) operating over the 6.0 to 18.0 GHz frequency range. Fabricated DFD phase correlator has been measured I or Q output signal, and analyzed frequency discrimination error. The operation of the proposed mixer type correlator has been analyzed by deriving some analytic equations. To design the phase correlator, this paper has modeled and simulated IQ mixer and 8-way power divider by using RF simulation tool. Designed phase correlator has fabricated and measured. The phase error and frequency discrimination error have been presented using by measured I and Q output signal. Over the 6.0 ~ 18.0 GHz range, the root mean square(RMS) phase error is 4.81°, RMS and frequency discrimination error is 1.49 MHz, RMS.

온도 센싱을 위한 SAW 센서 네트워크 설계 및 다중경로 반사파 제거

( Kyung-soon Lee ),( Kyung Heon Koo ) 한국항행학회 2023 韓國航行學會論文誌 Vol.27 No.4

If temperature management is required in factory or environmental monitoring, temperature can be measured by connecting various sensors wired or wirelessly. Surface acoustic wave sensors measure temperature using changes in acoustic waves on the sensor surface according to temperature, and are useful for wireless networks. In this paper, in order to build a wireless temperature measurement system in the 900 MHz frequency band, the temperature characteristics of the passive SAW sensor were measured, and the analysis and removal of multipath reflection wave effect inside the high temperature chamber were conducted. The resonant frequency of the SAW sensor was measured, and radio transmission/reception and multipath reflected wave removal techniques were proposed in the shielded chamber.

Airway Reconstruction With Carrier-Free Cell Sheets Composed of Autologous Nasal Squamous Epithelium

Koo, Jaseok P.,Kim, Chang-Hoon,Lee, Jeung-Gweon,Kim, Kyung-Su,Yoon, Joo-Heon The American Laryngological, Rhinological Otologic 2007 The Laryngoscope Vol.117 No.10

OBJECTIVES/HYPOTHESIS:: Although skin has been the most effective graft material for reconstructing the airway lumen, the use of squamous epithelium has many problems. If autologous airway squamous epithelium could differentiate into mucociliary epithelium after in vivo grafting, it could be an answer to these problems. In this study, we wanted to examine whether carrier-free nasal epithelial cell sheets composed of autologous squamous epithelium could be used as a substitute for skin in airway luminal reconstruction in three maxillectomy patients. STUDY DESIGN:: In vitro biochemical experiments with in vivo applications. METHODS:: We cultured nasal squamous epithelium from three maxillary cancer patients prior to maxillecotmy. These squamous cell sheets were grafted on the forearm free flap, and, after maxillectomy, the surgical defect was reconstructed with a prefabricated myocutaneous radial forearm free flap with the cultured nasal squamous epithelium. At 1 and 3 month intervals after the reconstructive surgery, the cultured cell grafted area was investigated with histologic phenotype, comparing the skin grafted area. RESULTS:: The autologous nasal squamous epithelial cell sheet differentiated into mucociliary epithelium without the crust or mucus stagnation that is usually observed in cases in which skin graft is used for airway reconstruction. CONCLUSIONS:: We suggest that autologous cultured nasal squamous epithelium, which differentiates into mucociliary epithelium after in vivo grafting, can be used as a clinically relevant substitute for skin graft in airway luminal reconstruction.

Identification of Novel Autoantibodies in Type 1 Diabetic Patients Using a High-Density Protein Microarray

Koo, Bo Kyung,Chae, Sehyun,Kim, Kristine M.,Kang, Min Jueng,Kim, Eunhee G.,Kwak, Soo Heon,Jung, Hye Seung,Cho, Young Min,Choi, Sung Hee,Park, Young Joo,Shin, Choong Ho,Jang, Hak C.,Shin, Chan Soo,Hwan American Diabetes Association 2014 Diabetes Vol.63 No.9

<P>Autoantibodies can facilitate diagnostic and therapeutic means for type 1 diabetes (T1DM). We profiled autoantibodies from serum samples of 16 T1DM patients, 16 type 2 diabetic (T2DM) patients, and 27 healthy control subjects with normal glucose tolerance (NGT) by using protein microarrays containing 9,480 proteins. Two novel autoantibodies, anti-EEF1A1 and anti-UBE2L3, were selected from microarrays followed by immunofluorescence staining of pancreas. We then tested the validity of the candidates by ELISA in two independent test cohorts: <I>1</I>) 95 adults with T1DM, 49 with T2DM, 11 with latent autoimmune diabetes in adults (LADA), 20 with Graves disease, and 66 with NGT and <I>2</I>) 33 children with T1DM and 34 healthy children. Concentrations of these autoantibodies were significantly higher in T1DM patients than in NGT and T2DM subjects (<I>P</I> < 0.01), which was also confirmed in the test cohort of children (<I>P</I> < 0.05). Prevalence of anti-EEF1A1 and anti-UBE2L3 antibodies was 29.5% and 35.8% in T1DM, respectively. Of note, 40.9% of T1DM patients who lack anti-GAD antibodies (GADA) had anti-EEF1A1 and/or anti-UBE2L3 antibodies. These were also detected in patients with fulminant T1DM but not LADA. Our approach identified autoantibodies that can provide a new dimension of information indicative of T1DM independent of GADA and new insights into diagnosis and classification of T1DM.</P>

스마트워터그리드 물 사용 자료를 이용한 단기 물 수요예측 연구

구강민(Koo, Kang Min),한국헌(Han, Kuk Heon),전경수(Jun, Kyung Soo),염경택(Yum, Kyung Taek) 대한토목학회 2022 대한토목학회 학술대회 Vol.2022 No.10

다중배열 디지털필터를 이용한 위성비콘 수신기 설계

이경순(Kyung-Soon Lee),구경헌(Kyung-Heon Koo) 한국전자파학회 2016 한국전자파학회논문지 Vol.27 No.10

비콘 수신기는 위성에서 송출된 비콘 신호를 검출하여 그 신호세기를 측정하는 장치이다. 위성에서 송출된 비콘 신호는 지구국의 안테나를 목표 위성 방향으로 이동시키는 포지셔너의 조정 및 송신출력 제어 목적을 위한 것으로 무변조 저전력 연속파(CW)로 구성되어 있다. 일반적으로 비콘 신호 검출은 협대역 아날로그 필터를 사용한 RSSI(Received Signal Strength Intensity) 방식이 대표적으로 사용되고 있으나, 온도변화 및 장시간 동작에 따른 위성 송출 비콘 주파수 변동이 발생됨에 따라 비콘 수신기에서 주파수를 추적하는 스캔 기능 구현을 필요로 한다. 본 설계에서는 보다 빠른 비콘 신호 검출을 위하여 협대역 디지털필터를 다중 배열하여 비콘 주파수를 추적하고, SNR(Signal to Noise Ratio) 방식에 의한 비콘 신호 검출방식 수신기로 설계한다. 이를 위하여 위성과 지구국 사이의 강우감쇠를 고려한 무선채널 링크 버젯을 사용하여 비콘 신호 수신 C/No 및 비콘 신호 검출을 위한 필요 C/N을 고려한 뒤 디지털필터의 대역폭 및 배열 개수를 도출한다. The beacon receiver is an equipment which detects and measures the signal strength of transmitting satellite beacon signal. Beacon signals transmitted by satellites are low power continuous wave(CW) signals without any modulation intended for antenna steering to satellite direction and power control purposes on the earth. The beacon signal detection method using a very narrow band analog filter and RSSI(Received Signal Strength Intensity) has been typically used. However, it requires the implementation to track the frequency at the beacon receiver, thus a beacon frequency variation of the satellite due to temperature changes and long-term operation. Therefore, in this paper, the beacon signal detection receiver is designed by using a very narrow band digital filter array for a faster acquisition and SNR(Signal to Noise Ratio) method detection. For this purpose, by calculating the satellite link budget with the rain attenuation between satellite and ground station, and then extracting the received C/No of the beacon signal, this work derives the bandwidth and the array number of the configured digital filter that gives the required C/N.

CoMo/γ - Al2O3 촉매상에서 Ni - TPP 의 수소첨가탈금속 반응에 관한 연구

김경림,최기섭,구헌서,강상윤 한국화학공학회 1991 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.29 No.1

CoMo/γ-Al₂O₃ 촉매상에서 250-450℃의 온도와 30×10^5-60×10^5 Pa의 압력 그리고 접촉시간 0.009-0.034gcat.hr/㎖ feed 범위에서 Ni-tetraphenylporphyrin(Ni-TPP)의 pyridine 존재시 수소첨가탈금속반응에 관하여 연구하였다. Ni-TPP의 수소첨가탈금속반응은 pyridine 양이 증가함에 따라서 전화율 감소가 발생하므로 pyridine은 수소첨가탈금속반응을 억제한다. 350℃ 이상의 온도에서 Ni-TPP의 반응은 외관상 1차로 진행하였으며 그것으로부터 Arrhenius plot을 하여 구한 활성화 에너지는 약 10㎉/mole이었다. Fresh 촉매와 aged(숙성) 촉매의 흡착 탈착 isotherm을 구해 보고 pore size distribution을 측정해 본 결과 촉매의 macropore에서 pore mouth-plugging현상이 일어난 것을 알 수 있었다. Hydrodemetallation(HDM) of Ni-tetraphenylporphyrin(Ni-TPP) was studied over CoMo/γ-Al₂O₃ catalyst at temperatures between 250℃ and 450℃, the total pressure between 30×10^5 Pa and 60×10^5 Pa, the contact times between 0.009 gcat.hr/㎖ feed and 0.034 gcat.hr/㎖ feed, and pyridine concentrations between 3.6 mole % and 16.7 mole %. HDM of Ni-TPP was inhibited by pyridine because the increase of pyridine concentration caused the decrease of HDM conversion. The reaction rate of Ni-TPP was found to be apparently 1st order over 350℃ and its activation energy was determined to be about 10 ㎉/mole by Arrhenius plot. Pore mouth-plugging phenomena were shown by ad/desorption isotherm and pore size distribution of fresh and aged catalysts.