HF통신 시스템을 위한 ALE 신호의 동기

오상균 한국통신학회 1996 韓國通信學會論文誌 Vol.21 No.7

Recently, by emerging of the ALE techniques that make it possible to providereliable communications link automatically, high frequency communiation is newly used as emergency communication and back-up for satellite communications. ALE signal is transmitted in burst, and the received signal is subject to distortions by detrimental multipath fading channels. In the case of that channel, the performance of ALE system is highly dependent upon that of synchronization techniques. In this paper, M-ary FSK signals are detected by a bank of bandpass filter, which is implemented using recusive DFT(Discrete Fourier Transform). Also an acquisition and trancking algorithm are designed uisng parallel structure and early-late-gate methods respectively. Finally, we verify the performance ofthe proposed synchronization algorithm by the computer simulation.

고분자량의 폴리에틸렌테레프탈레이트의 겔특성 및 용액성막한 막의 물성

오상균,육지호,하완식,O, Sang-Gyun,Yuk, Ji-Ho,Ha, Wan-Sik 한국섬유공학회 1991 한국섬유공학회지 Vol.28 No.4

High molecular weight poly(ethylene terephthalate) (PET) was prepared by using a modified postpolycondensation method. Gelation temperature(아 and gel melting temperature (Tt) of PET-nitrobenzene gel were measured, and gel forming process and non-isothermal c.ystallization behavior were investigated. and 75, was increased with increasing concentration of PET and decreased with increasing molecular weight of the polymer. The crystallization rate was decreased with increasing molecular weight and concentration. The high molecular weight PET in phenol/tetrachloroethane (614%) was cast onto film. Optimum critical concentration in the solvent casting was determined by viscosity measurement, and it was found that this concentration was decreased with increasing molecular weight of the polymer. The solvent cast film exhibited almost same modulus, but its tensile strength was increased with increasing molecular weight of the polymer.

원주 로터형 레오메터에 의한 고유동콘크리트의 유동성 평면방법 ( Evaluation Method of Fluidity of Self-Compacting Concrete by The Cylinder Rotor Rheometer )

오상균,강병희,토모사와 푸미노리 대한건축학회 1998 大韓建築學會論文集 : 構造系 Vol.14 No.6

본 연구는 콘크리트 배합설계 및 품질관리에 기여할 목적으로 점성 유체속 을 저속으로 운동하는 원주가 받는 저항에 관한 해석을 응용함으로써 콘크 리트의 레올로지 정수 산정방법을 이론화 함과 동시에 그 이론적인 배경을 바탕으로 콘크리트용 원주 로터용 레오메타(The Cylinder Rotor Rheometer)를 개발하였다. 원주 로터형 레오메터는 직접 원주체를 시료에 삽입한 후, 회전시켜 토르크치를 측정하는 장치이며, 측정되어진 토르크치 와 회전속도는, 원주의 해석으로부터 얻어진 전단응력 τ 와 전단속도 γ 에 관한 두 식에 의해 유동곡선으로 환산 가능하다. 또한, 레올로지 곡선 산출식의 타당성을, 모르터 모델과 고유동콘크리트를 대상 시료로 한 실험을 통해 검증하였다. 실험결과, 본 연구에서 고안한 원 주 로터형 레오메터를 이용한 빙함유체의 유동성 평가가 레올로지적으로 가능하였다.

고유동콘크리트의 유동설계방법 ( Flowability Design Method of Self-Compacting Concrete )

오상균 대한건축학회 2000 大韓建築學會論文集 : 構造系 Vol.16 No.6

재생시멘트의 품질향상을 위한 제조방법에 관한 연구

오상균 한국건축시공학회 2004 한국건축시공학회지 Vol.4 No.2

The recycle of domestic waste concrete is, however, still in an early stage, and it has been only partially being used for the road fillers. As a counter-plan of activating recycled concrete, we have confirmed the hydration possibility of the waste concrete powder from the experiment on recycling the aggregate powder since 2000. Though that study, we have known that the strength is increasing when the baking time is longer, and baking temperature maintain in 700℃. Also, the quality is lowered because of the fine aggregate powder which has a bad influence on flowability & compression strength by adhesion of mortar on the aggregate face. Therefore, mortar and interfacial separation of aggregate are large in proper quality for concrete recycling is expected that affect.The purpose of this study is to investigate effective aggregate separation and to determine the most suitable production method controlling the duration of baking time for recycled cement from the compressive strength, X-ray diffraction and ingredient analysis test.

초음파신호의 특징추출에 의한 SUS 304강의 크리프 열화도 평가

오상균,안병욱 한밭대학교 생산기반기술연구소 2001 생산기반기술연구소 논문집 Vol.1 No.1

This study is to investigate the applicability of ultrasonic pattern recognition using ultrasonic wave. In order to study the feature of frequency range, sound velocity and attenuation coefficient was extracted from the time series of ultrasonic signals according to material degradation. Creep degradation and accompanied microstructal change in SUS 304 steel caused a decreasing tendency in sound velocity, lowering in center frequency and power spectrum, and increasing in attenuation coefficient. The quantitative extracting method of chaos feature using quadrant distribution value was applied to analyze the feature of frequency range and geometrical shape of chaotic attractor from ultrasonic signals of SUS 304. From the above results, the present study has been suggested a method which improve the accuracy on the evaluation of material degradation.

무기광촉매 수용액의 실내 오염물질 분해성능 및 수질정화 성능 평가

오상균,조은영 대한건축학회지회연합회 2007 대한건축학회연합논문집 Vol.9 No.3

According to the advance of the industrial technique, the human has been lived a convenient and affluent life. But, it recently was raised social problems, such as Sick House Syndrome occurred from indoor air pollution, the water pollution from the domestic sewage. In the long run, we expect to run up expenses for processing pollutants by these indoor and outdoor environmental problems. Therefore, the purpose of this study is to establish a fundamental data about the photocatalyst for the improvement of indoor air and water quality. As the results of this study, the ingredient of colored tar which are on the coated interior finishing materials is decolorized as confirmed visible for a duration of time. Also, the purification on the water quality is that the concentration of BOD, T-N, T-P decreased than the initial. This means that the water quality is increased by using it.

Optimization of the Hot Workability for an Extrude AZ80 Mg Alloy using the Processing Map and Kriging Meta- Model

오상균,이광기,나영상,서창희,정윤철,김영석 한국정밀공학회 2015 International Journal of Precision Engineering and Vol.16 No.6

Mg alloy has a hexagonal close-packed(HCP) lattice crystal structure, which has fewer slip systems than other structures, and plastic deformation is difficult to achieve at room temperature. To improve its workability, the non-basal plane slip must be activated by increasing the deformation temperature. In this study, the hot deformation behavior of the AZ80 Mg alloy was examined within the temperature range of 250-400oC and the strain rate range of 0.001-10/s, based on the dynamic materials model. The hot deformation characteristic value was determined using the dynamic materials model (DMM), and was approximated using Kriging meta-model. Based on the results, deformation processing maps were derived, and the entire strains were examined to present the processing maps considering the strain during forming. In addition, the processing maps were established considering the hardness after forming, and the process window was presented considering both the formability and the strength of the parts.

폴리에틸렌 튜브를 사용한 경량 시멘트 경화체의 기초 물성 연구

오상균 대한건축학회 2007 大韓建築學會論文集 : 構造系 Vol.23 No.2

The purpose of this study is to analyze the physical properties of the hardened lightweight cement using the polyethylene tube and to make the fundamental data regarding a new lightweight concrete development. The aerated concrete is displaying various effects such as lightweight, insulation characteristic and it is coming to be widely applied the slab layer of apartment as an insulating material but currently the aerated concrete has many problems. Therefore, demonstrating similar property of former aerated concrete and improving the defects, developing new hardened cement is needed. In this study, we predict adopting possibility of hollow core polyethylene tube, as a material to make cement hardening containing a lot of void. Therefore, in this study, we make light weight cement hardening using polyethylene tube and experiment basic property of it. So we changed the mixing ratio, a diameter and length of the polyethylene tube and improved the compressive strength and unit capacity weight of the lightweight cement hardening body. From like this result, we judge that the aerated concrete is a developmental possibility.

정밀분급방법을 이용한 폐콘크리트 미분말의 고품질재생시멘트 개발

오상균,홍영태 대한건축학회 2007 大韓建築學會論文集 : 構造系 Vol.23 No.9

The purpose of this study is the concrete defect happen from aggregate minute's particle mixing in process that make waste concrete as recyclable cement puts to practical use constructing basic data for design of mix proportion used recyclable cement and solves strength fall problem using micron separator, and does general recyclable cement high quality.As a result of X-ray diffraction(XRD) of rater HR-C than NR-C is aware that it come out the micron-separating to decrease the SiO2 peak below 50%. And a construction field which apply for compressive strength's 24~28MPa HR-C in order to realize NR-C of 44% and 51%. Recycle concrete capacity through improved recycle cement of manufacturing technique by micron-separating's new distribution more better improvement. Therefore, in this study, it need to more various study a recycle cement of high quality for reasonable and utility recycling than disposal concrete.