• 광산업정보
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• 통권2호
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• pp.62-67
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• 2001

• 한국공작기계학회논문집
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• 제15권3호
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• pp.59-66
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• 2006

In this paper, we suggested an evaluation method of cracks in a ceramic product by resonant ultrasound spectroscopy. For experiment, we manufactured nondestructive measurement system by resonant ultrasound spectroscopy and measured resonance frequencies of acceptable and cracked ferrules. The evaluation criterion of ferrule is based on the comparison of resonance frequencies between acceptable and cracked-ferrule. The criterion value that defined by suggested formula is 2. By using the criterion, it is possible to evaluate both acceptable and cracked-ferrule.

• 한국자동차공학회논문집
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• 제12권5호
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• pp.108-117
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• 2004

In this paper, a measuring NDT(nondestructive testing) system using RUS(Resonant Ultrasound Spectroscopy) was built for nondestructive evaluation of the flaw in a ceramic Ferrule. The principle of RUS is that the mechanical resonant frequency of the materials depends on density, and the coefficient of elasticity. The RUS system is the measuring which is to exite specimen and to inspect the difference of natural frequency pattern between acceptable specimen and specimen which has some defects. RUS system is configured of spectrum analyzer, power amplifier, PZT sensor and support frame. For defect evaluation by the RUS, we performed to measure natural frequency of Ferrule, both acceptable and cracked. In the case of Ferrule, the resonant frequency of cracked-Ferrule existed to higher frequency band than acceptable-Ferrule.

• 광산업정보
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• 통권11호
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• pp.38-41
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• 2002

중국은 개혁 개방 정책의 전환과 함께 경제 발전을 적극적으로 추진해 왔으며, 특히 최근에는 하이테크의 연구개발 및 활용, 정보화 수준 향상 등의 중요 지표는 복잡한 민족의식과 함께 선진국과의 경쟁열기를 형성했으며 인터넷은 이런 조류에서 앞장서서 중국 현대화 과정을 이끌어 오고 있다.

• 한국식품과학회지
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• 제50권1호
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• pp.8-13
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• 2018

말린 표고버섯을 다양한 조건(열수처리, 증기처리, 볶음처리)으로 조리 후, 항산화특성과 기능성 영양소인 리보플라빈, 에리타데닌, 그리고 에르고칼시페롤을 측정하여 생조리 표고버섯과 비교하였다. 총 폴리페놀함량이나 유리라디칼 소거능 등의 항산화 특성은 생조리군에서 가장 높았고 열수처리군에서 가장 낮게 나타났다. 표고버섯의 기능성 영양성분인 리보플라빈, 에리타데닌 함량 역시 생조리 버섯에서 가장 높게 측정되었으며 볶음처리>증기처리>열수처리 순으로 측정되었다. 지용성 영양소인 에르고칼시페롤의 경우 생조리버섯 뿐 아니라 열수처리, 증기처리군에서 모두 비슷한 함량을 나타내어 물이나 열처리에 변화가 없음을 보였고, 볶음처리군에서 약간 감소하는 경향을 보였다. 말린 표고버섯은 그 자체로 항산화특성 및 영양성분이 높으나 생조리의 상태로 섭취하는 경우가 드물기 때문에 다양한 조리조건에서 처리 후 비교했을 때, 버섯의 경도는 비슷했지만, 영양손실은 볶음 처리 시 가장 적었고, 열수처리 시 가장 많았다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.9-14
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• 2002

Ferrule is widely used as fiber optic connecters. In fiber-optic communications, the shape accuracy such as coaxiality and cylindricity of ferrule affects insertion loss. When coaxial grinding of ferrule supported by two pin, pin alignment and chucking accuracy are very important. In this research, the kinematic behavior of the ferrule center is investigated in the case where cone-shaped center pins and round circle hales which make contact with each other near the edge of the holes, using homeogenous coordinate transformation and numerical analysis. The obtained results are as follows: The alignment errors between center pins alone do not affect the rotation accuracy of ferrule. The alignment errors between center holes cause a sinusoidal displacement of ferrule. And the maximum displacement of ferrule centers increase in proportion to the center pin angle in the case of a fixed alignment errors

• 한국정밀공학회지
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• 제17권10호
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• pp.63-68
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• 2000

We present an automatic inspection system which been developed to evaluate the geometric tolerances of the optical fiber connectors with an dimensional accuracy of$\pm0.1\mnm$. The main part of the inspection system comprises a series of machine vision and laser scanning probes to measure the internal and external circle diameters along with concentricity by making the most of advanced edge detection algorithms. Actual experimental results obtained through various repeatability tests demonstrate that the system well satisfies the required industrial demands for in-situ inspection of optical fiber connections in real manufacturing environment.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1345-1348
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• 2003

The Ferrule for the Optical Communication Connector is the product to set the optical ares of an optical fiber very precisely. Therefore, it is required high expectations such as high dimensional precision and new including flaws. Up to new the optical instrument has been used for the defeat and shape inspection of the ferrule, but in the paper we examined the detectable defeat and expectation by using Resonant Ultrasound Spectroscopy(RUS). The RUS is the measurement which is to excite specimen and to inspect the difference at natural frequency pattern between acceptable specimen and specimen which has some defeats. We analyzed the difference of natural frequency pattern in the experiment using Spectrum Analyzer. And we compared the results in the experiment with those in the simulation from the explicit finite elements code, Nastran.

• 한국정밀공학회지
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• 제22권2호
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• pp.172-179
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• 2005

A high-precision centerless grinding machine has been recognized as a core equipment performing the finish outer-diameter grinding process of ferrules which are widely used as fiber optic connectors. In this study, in order to realize the high-precision centerless grinding machine, the structural characteristic analysis and evaluation are carried out on the virtual prototype consisted of the steel bed, hydrostatic GW and RW spindle systems, hydrostatic RW feed mechanism, RW swivel mechanism, and on-machine GW and RW dressers. The loop stiffnesses of centerless grinding machine are estimated based on the relative deformations between GW and RW caused by the grinding forces. And the simulated results illustrate that the concrete-filled bed has the considerable effect on the improvement of the structural stiffness of centerless grinding machine.

• 한국자동차공학회논문집
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• 제12권6호
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• pp.143-150
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• 2004

In this paper, resonant ultrasound spectroscopy(RUS) was used to determine the natural frequency of a ceramic ferrule and a ball lens. The ceramic ferrules are cylinderical shape with $\phi$ 2.56mm diameter and l0mm in length. Crack lengths of these ferrules are 10.40$\mu$m, 21.18$\mu$m and 32.35$\mu$m. The spherical ball lens was made of BK-7 glass, one's diameter in 2mm and 5mm. RUS system is consisted of spectrum analyzer, power amplifier, PZT sensor and support frame. The principle of RUS is that the mechanical resonant frequency of the materials depends on density and the coefficient of elasticity. Rus system is based on that given resonant frequency of the materials can be represented by the function of density and the coefficient of elasticity, and it is applied to excite specimen and to inspect the difference of natural frequency pattern between acceptable specimen and defective ones. Defect evaluation by RUS are performed to investigate the natural frequency measure of ferrule and ball lens.