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.

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.

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.

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>

ILS 항행안전신호 전파진행 모델링 및 수신 특성 연구

( Kyung-soon Lee ),( Kyung Heon Koo ) 한국항행학회 2024 韓國航行學會論文誌 Vol.28 No.3

The instrument landing system (ILS) is an international standard established by the International civil aviation organization (ICAO) as one of the landing support facilities for aircraft. This system consists of a localizer (LOC) that provides orientation information about the runway to indicate the approach direction, a glide path (GP) that indicates the appropriate approach glide slope, and three of marker beacons (MB) that indicates the distance to the runway landing edge. In this study, we predicted the received signal strength by altitude and distance for LOC signals transmitted from the ground and analyzed the difference with the signal strength measured in the actual environment. Our objective is to develop signal strength prediction technology and apply it to the real environment.

UAM 복합 항법을 위한 C 밴드 지상기반 전파 항법 시스템 연구

이경순 ( Kyung-soon Lee ),조용운 ( Yong-un Cho ),김민정 ( Min-jung Kim ),구경헌 ( Kyung Heon Koo ) 한국항행학회 2023 韓國航行學會論文誌 Vol.27 No.4

본 연구는 기존 UAM에서 주로 사용하는 GNSS 항법과 협동 운용할 수 있도록 지상기반 C밴드 주파수 (5.03~5.15GHz)를 이용한 전파항법 VOR/DME 구현에 관한 것이다. 이것은 항공우주를 감독하는 미연방항공국 규칙 Title 14 CFR- Aeronautics and Space 135.165에서 제시한 ‘2개 이상의 독립적인 항법소스를 비행체에 적용’ 규정사항을 충분히 만족할 수 있는 항법기술 중 하나이다. 본 연구에서는 무인항공기용 주파수 5.03~5.15 GHz를 사용하였으며, 무인항공기에서 도착 버티포트까지의 방위각과 거리정보를 획득에 필요한 VOR/DME 시스템 구현을 수행하였다. 이를 위하여, 전파 전파경로 손실분석에 의한 링크버짓 도출, 소형화된 도플러 VOR용 안테나 형상설계 및 기존 항공기용 보다 측위거리 해상도가 향상된 DME 설계 등을 수반하였다. 본 연구 결과물은 지상기지국과 UAM에 장착할 수 있는 단말기로 구성되며, 각각 시제품 제작 및 주요 성능검증을 수행하였다. This study focuses on the implementation of C-band radio navigation in the 5.03 ~ 5.15 GHz terrestrial band to cooperate with GNSS navigation mainly used in existing UAMs. This is one of the navigation technologies that can fully satisfy the requirements of Title 14 of CFR-135.165. According to the FAA, the use of two or more independent navigation sources for aircraft is proposed for aircraft. This study proceeded with the link budget derivation through radio wave propagation path loss analysis, and antenna shape design for miniaturized Doppler VOR, and DME design with enhanced positional distance resolution compared to conventional aircraft. The ground navigation system which is the result of this study, consists of a VOR/DME ground station and a terminal that can be mounted on UAM. Significant performance was confirmed through the production and testing of each prototype.

Fricke 용액을 이용한 선량측정

오헌진,김귀야,이현구,정승환,양현규,이선경,남정우 식품의약품안전청 2000 식품의약품안전청 연보 Vol.4 No.-

Fricke선량측정은 전리함 선량측정과 비교하여 몇가지 장점을 가지고 있어서 AAPM과 ICRU에 의해 교정쓱 물흡수선량 결정의 또 다른 방법으로 권고되고 있다. 실험과정은 전리함에 의한 상대적 측정을 기본으로 Fricke 선량측정은 기준선(mCo γ-선)에서 수행되었다. Fricke 선량계 용액의 제조에 사용되는 황산에 포함된 미량의 불순물은 ferric 이온의 화학적 효율에 영향을 줄 수 있파. 본 논문에서는 미량의 불순물에 대한 연구를 위하여 두가지 종류복 종깐으로 Fricke 용액을 제조하였다. Suprapur의 사용결과 표준편차는 7.92% 감소하는 것으로 나타났다. 또한 불확도 르2% 수준의 Fricke 선량측정시스템을 확립하였다. Fricke dosimetry has some adva?tageous properties compared to ionization chamber dosimetry iud therefore has beeR recommended by both AAPM and ICRU as analternative method for the calibration and the determination of absorbed dose in water- Theexprrimental procedure was based on refative measurements with ionigation chamber and frickedosimetry performed in the reference beam (oCo γ - radiation). The sulphuric acid used for thepreparation of the FBicke dosimeter solution may contain trare impurities that can affect theyield of ferric lons. In the present work Fricke solutions prepared from two brands of sulphuricacid were cornpgred in order to study any influences of trace 3mpurities. It was shown that theuse of suprapur resulted in a reduction of the 7.92% standard deviation. The results reported aFricke dosimefry system of thr uncertaintf ±2%.