低壓用 실(絲)휴즈의 지름과 溶斷電流

司空鍵 영남이공대학 1977 論文集 Vol.6 No.-

This paper investigates the relative equation between the melting current and diameter of the thread fuses which are manufactured in Korea. By the research the main results obtained as the following. 1) The relative equation between the melting current I and the diameter d of thread fuses is I=ad 3/2(here a is the constant value) 2) The equation is I=ad7/5 by means of manufacturing process in Korean goods. 3) The constant a of Korean products is about 7.203 to 12.623. 4) The melting time of the rating current 5A twofold fuse is shotter than the rating current 10A fuse.

세라믹/고분자 1-3형 복합압전체 초음파 트랜스듀서를 사용한 근접거리변동 측정용 레벨Limit스위치에 관한 연구

사공건,김흥근,박경일 東亞大學校 2003 東亞論叢 Vol.40 No.-

In this study, an ultrasonic transducer is fabricated with 1-3 type composite resonators. Pulse-echo responses of an ultrasonic transducer are investigated in underwater dependent on the variable designated water-level. LED Output signals of a level limit with changing a water level are obtained by the 1-3 type self-made ceramics/polymer composite transducer and electric measuring unit. LED is turned on at above the up-limit level with increasing a water level, and LED is turned on at less level than the down-limit level with decreasing a water level. There was good agreement between the virtual water level and output LED signal by using the self-made water-detecting system.

자성분말의 초투자율 측정방법과 그 응용

사공건,전홍배,허 진,김철한 東亞大學校 2001 東亞論叢 Vol.38 No.-

In this study, a measuring system of the initial permeability of soft-ferrite powder is developed by using a linear variable differential transformer's coil, and investigated about a demagnetizing factor. Magnetic powder is extensively used for a magnetic fluid and microwave absorber's materials etc.. In these applications, it is significantly important for us to measure an initial permeability of magnetic ceramic powder. Unfortunately, there are not any measuring equipment and method directly up to the present.

초음파 트랜스듀서용 PZT-고분자 1-3-0형 복합압전체의 유전 및 압전특성

양윤석,최헌일,사공건 東亞論叢 1999 東亞論叢 Vol.36 No.-

In this study, piezoelectric composites with 1-3-0 connectivity have been studied. A piezoelectric ceramic PZT prepared by the Wet-Dry Combination method is used as a filler phase in mixture of the third filler phase and Eccogel polymer matrix. The density and stiffness of 1-3-0 type composites were decreased with increasing the third phase.

3종 페라이트/고무 복합형 전파흡수체에 있어서 재료정수의 주파수 의존성

김철한,전홍배,유영준,사공건 東亞大學校 1999 東亞論叢 Vol.36 No.-

In this study, ferrite/rubber composite specimens have prepared by molding and curing the mixture of matrix silicon rubber and three kinds of filler particle Mn-Zn/Ni-Zn/Ni₂Y ferrite which are synthesized by the coprecipitation mehtod. The mixing ratio of three kinds of ferrite filler paticle gave variety to adjust the material constant of composite microwave absorbers. Material constants of composite specimens were calculated from the measured variables(s-parameter) over the frequency range from 1 to 12 GHz by means of Network Analyzer(HP8722D) with a co-axial type air line. The reflection loss was calculated from material constants on the impedance matching map utilizing simplex method. By chaging mixing ratio of three kinds of ferrite filler particle, the frequency range over than 20dB were relatively broaden and maximum reflection loss were remarkably reduced to others specimens excepted specimen D. Finally, it could make microwave absorber to be used for C-band frequency range.

導電性 高分子의 電氣化學的 DOPING에 의한 電氣的 特性

具轄本,朴鄭學,司空鍵 東亞大學校 1990 東亞論叢 Vol.27 No.1

Aromatic compounds such as Polyparaphenylene(PPP) and Polyparaphenylenvinylene(PPV) were polymerized by chemical and electrochemical synthesis. The electrical properties with various dopants and concentrations for the PPV and PPP were studied. The results are as follows: 1) The conductivities of PPV with BF₄dopants and I₂doped PPP were much incresed(i.e., 10 adn 6 orders, respectively) than those of without dopants. 2) The conductivities of PPV and PPP with NH₃gas were much increased(i.e., 2 and 10 orders, respectively) than those of without NH₃ gas. 3) The variations of ESR line width and spin density were in good agreement with those of polaron and bi-polaron models. As a summary, PPV and PPP were made by chemical and electrochemical synthesis could be appropriate for the gas sensors.

광대역형 Ferrite/Rubber 복합형 전파흡수체의 제작 및 특성

김한근,김삼룡,사공건 東亞大學校 1996 東亞論叢 Vol.33 No.-

In this paper, the microwave absorption properties of two layered absorber were evaluated. The two layer absorber were composed of Ni-Zn ferrite/rubber and Ferroxplana/rubber absorber. The excellent absorption properties of the two layered absorber were shown that the transforming layer was Ferroxplana/rubber absorber and the absorbing layer was Ni-Zn ferrite/ rubber absorber and that the optimal thickness of transforming and absorbing layer were 4 and 1(mm), respectively.

자기효과를 이용한 광 Scanner의 반사각 개선

사공건,김흥근,신광호 東亞大學校 2004 東亞論叢 Vol.41 No.-

This paper is focused on the improvement of reflection angle of an optical scanner by changing a shape of a torsion bar attached with an optical scanner reflector(mirror). In order to improve the light efficiency of the optical scanner by virtue of the magnetic effect, which tiny magnets are attached under both ends of the optical scanner reflector. and hence the optical scanner reflector was operated in relatively lower driving voltage. By changing the torsion bar's shape I type into S type, we've got the lower resonant frequency(32.5Hz) of an optical scanner than that of conventional one(50Hz). According to these results. The reflection angle of an optical scanner with magnets was much larger in the range of about 14.8° compared to one without a magnet. By making use of a magnetic actuator instead of a conventional electrostatic actuator, the optical scanner was less influenced from outdoor dust or moisture.

Ferrite/Rubber Composite의 혼합비에 따른 전파흡수 특성

김한근,박상하,사공건 東亞大學校 1992 東亞論叢 Vol.29 No.1

In this paper, the permeability(??), dielectric constants(??) and absorption characteristics of Ferrite/Rubber composites were investigated. The composite specimens were prepared by molding and curing the mixtures of matrix rubber and Ni-Zu ferrite powders which were synthesized by wet-direct method. The permeability(??) of specimen was decreased from 2.58 to 0.7 in the range of 1∼7 (GHz) and kept constant O. .8 at higher than 7(GHz). The higher the frequency was, the less the values of μ, was from 1.57 to 0.03. The optimum thickness of microwave absorber(F/R=4), utilizing the Smith chart, was about 5(mm). The reflection loss was shown over than 20(dB) from 5.5(GHz) to 4.5(GHz) at 5(mm) thickness and relative band width(B/fm) was about 35(%).

Ferroxplana Y-type(Ni₂Y) 磁性 분체의 합성 및 자기적 특성

박상하,사공건 東亞大學校 1993 東亞論叢 Vol.30 No.1

In has been prepared by a coprecipitation method for Ferroxplana Ni₂Y(Ba₂Ni₂Fe O ) magnetic particles, which is one of the hexagonal ferrite. The coprecipitates were synthesized by adding aqueous solution of BaCl₂·2H₂O, Nicl₂·6H₂O and FeCl₃·6H₂O(of which the mole ratio is Ba²+:Ni²+:Fe³+=1:1:6) to a mixture of NaOH and Na₂CO₃ solution. The shape of Ferroxplana Ni₂Y magnetic particles obatined at the calcined temperature 1,100(℃) was hexagonal plate-like, average particle size was 2(m), and aspect ratio was more than 7.