• 비파괴검사학회지
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• 제32권5호
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• pp.509-517
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• 2012

본 연구에서는 상용화된 monomer-cast nylon (MC nylon)계 고분자 재료로 만든 6종류의 시편에 대하여 감쇠계수 및 위상속도와 같은 초음파 특성의 온도 및 주파수 의존성을 조사하였다. 시편의 초음파 특성은 수중에서 2 MHz부터 8 MHz까지의 광대역 주파수 범위에 대하여 펄스투과법을 이용하여 측정하였다. 수온은 $10^{\circ}C$부터 $60^{\circ}C$까지 $10^{\circ}C$ 간격으로 변화시켰다. 측정에 사용된 모든 시편에서 감쇠계수는 주파수가 증가함에 따라 증가하였으며, 주파수의 지수 의존성 n이 선형 (n=1)에서 약간 벗어난 1.16부터 1.44이내의 값을 가졌다. 위상속도는 $60^{\circ}C$에서 ivory 시편을 제외한 모든 경우에 대하여 주파수가 증가함에 따라 감소하는 음의 분산 특성을 나타냈다. 주파수에 의존하는 위상속도는 모든 시편에서 온도가 증가함에 따라 감소하는 특성을 나타내었다.

• 한국정밀공학회지
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• 제22권2호
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• pp.139-147
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• 2005

The lubricant impregnated MC nylon has good frictional properties, but its mechanical strength is inferior to steel for the mechanical elements. For the tribological application Nylon as gears, sliding bearings, cam and etc, the steel shafts are fitted in pre-heated nylon cylinder by a process of interference expansion fit and bonded by induction heating method. The joint shear strength of the two materials was measured by a universal test machine. From the study, the adhesive shear strength between these two materials was affected by the factors of the interference between nylon and steel, the size of nylon cylinder, knurl of steel shaft and inducting heating conditions. The most effective jointing conditions were analyzed and decided for the practical application in the industry.

• 한국산학기술학회논문지
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• 제7권4호
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• pp.743-748
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• 2006

본 논문에서는 연구에서는 Nylon6를 기재로 하여 두 가지 Melamine계 난연제(melamine cyanurate: MC-100 and melamine phosphate:MPP-100)를 사용한 난연 Nylon를 개발하여 난연성 및 물성평가를 수행하였다. 난연Test는 UL-94 측정방법(수직연소 시험방법)을 이용하였고, 물성평가는 만능물성시험기(UTM)를 이용하여 인장강도, 굴곡강도, 굴곡탄성율 등을 측정하였고, 충격강도 시험기를 이용하여 충격강도를 측정하였다. 또한 Nano-clay(Cloisite 30B) 5wt%를 사용하여 물성에 미치는 효과를 관찰하였다. 수지의 난연성 평가결과에 의하면, 난연제의 함량이 5wt% 이상이면 V0급을 얻을 수 있었다. 난연제 함량이 증가함에 따라 인장강도. 굴곡강도는 감소하고, 굴곡탄성율은 증가하였다. MC-100의 경우, 5wt%까지는 Nylon6의 동등 이상의 물성을 유지하였다. Nano-clay의 경우, 분산 상태가 불량하여 기대 수준의 물성 향상과 난연 효과는 얻지 못했다.

• 한국기계가공학회지
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• 제19권6호
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• pp.73-79
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• 2020

Although engineering plastics that are light-weight and have excellent mechanical performance have been widely applied in various industries in place of steel structures to reduce the burden of cost and time, there have been few studies related to their surface roughness. This study aims to evaluate the optimal effects of feed rate, cutting speed, and depth of cut as cutting parameters as well as nose angle on the surface characteristics of MC nylon in CNC lathe machining. To determine the best conditions under different nose radii, the experiments were performed based on the Taguchi L9(34) orthogonal array method, in which the resulting data was analyzed using the S/N ratio and ANOVA. Results indicate that the most significant contribution was feed rate followed by nose angle and cutting speed, whereas the depth of cut did not influence the performance. This study demonstrates that the suggested method for improving the surface finishing of MC nylon is efficient compared with results obtained from experimentation and prediction.

• 한국기계가공학회지
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• 제2권3호
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• pp.84-89
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• 2003

The joint method and characteristics of lubricant Impregnated MC nylon and metal are analyzed. Considering the productivity and economics, two materials are Joined with the process of turning, knurling, and induction heating. The Joint strength is determined by adhesion of the melted nylon, the size of knurl, and the interference from the difference of the diameters. The parameters affecting induction heating process are analyzed. The adhesion strength of the melted nylon is measured. Finally the joint strength is analyzed in the environments of low, room, and high temperature. The nylon/metal Joined material is expected to be widely used as the sliding machine elements with good friction and shear strength.

• 한국정밀공학회지
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• 제20권3호
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• pp.125-132
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• 2003

The joint method and characteristics of MC nylon and metal are analyzed. Considering the productivity and economics, two materials are joined with the process of turning, knurling, and induction heating. The joint strength is determined by adhesion of the melted nylon, the size of knurl, and the interference from the difference of the diameters. The adhesion strength of the melted nylon is measured. The effects of the knurl size and diameter difference are analyzed with the statistical methods. Finally the joint strength is analyzed in the environments of low, room, and high temperature. Based on this study, the nylon/metal material is expected to be widely used as the sliding machine elements with good lubrication and strength properties.

• 열처리공학회지
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• 제15권5호
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• pp.228-233
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• 2002

The characteristics of the induction heating process are analyzed for the joint of nylon and metal. The temperature of metal surface is measured using thermocouples. The relations of temperature and induction heating parameters are analyzed. Heat equation models are constructed and the temperature distribution is predicted using Fluent. The effects of heating parameters on the joint strength are evaluated. Finally, the optimal parameters of induction heating process are proposed as 16kW and 6 seconds.

• Journal of electromagnetic engineering and science
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• 제7권3호
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• pp.122-128
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• 2007

In this paper, we present the design and measurement of a side-fed circularly-polarized patch antenna with a dielectric loading. The antenna consists of a comer-truncated rectangular patch, an L-shaped ground plane, a dielectric loading material, and a coaxial probe. An antenna operating at the UHF band (910 MHz) for the RFID reader applications is optimized using a commercial software. The size of the patch is reduced by a factor of 1.73 by loading the patch with mono-cast(MC) nylon. Measurements of the fabricated antenna show performance characteristics comparable to those of much larger commercial RFID reader antennas.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.245-248
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• 1997

The distilled water is used for the ultrasonic wave propagating material in the measurements of broadband ultrasonic attenuation (BUA) that is applied in industrial and medical applications, The acoustic impedance of water is significantly changed with its temperature. Therefore, the quantitative evaluation of BUA with temperature and the ultrasonic wave propagating distance is highly needed. In this study, we evaluated the variation of attenuation with change in temperature. To measure the variation of BUA in the low frequency region at the temperatures, 27$^{\circ}C$, 29$^{\circ}C$, and 31$^{\circ}C$, we tested the Plyethylene, Teflon, MC-Nylon, Urethane specimens and analyzed the center frequency, frequency bandwidth, spectral peak amplitude. The results showed that BUA value appeared to be lower with increasing temperature. This may be due to the fact that the frequency feature of ultrasonic wave is affected by not only the specific gravity, acoustic impedence, but material crystalline, porosity, the distance of ultrasonic wave propagation in water.

• 전기학회논문지
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• 제61권9호
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• pp.1300-1305
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• 2012

A triaxial Blumlein pulse forming line has been designed to generate a pulse whose voltage is ~300 kV, pulse duration is ~5 ns, and rise time is ~500 ps. It turns out, however, that the rise time of the pulse becomes much longer than 500 ps due to parasitic inductances and capacitances existing inside the system. A peaking switch has been developed to shorten the rise time of the pulse from Blumlein pulse forming line. In the peaking switch, a wedge-shaped dielectric material (MC 901 nylon) is employed to surround the electrode on the antenna side. This shape inhibits an abrupt change of the output impedance, thereby minimizing the reflection of the output pulse. Experimental results show that the peaking switch is capable of improving the rise time of the pulse at a level of 500 ps.