• 청정기술
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• 제10권1호
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• pp.27-35
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• 2004

현재 국내 피혁 업체에서는 대표적인 공해 산업으로 인식되어 있는 피혁 산업의 환경 문제를 해결하기 위하여 심혈을 기울이고 있다. 피혁 선진국에서는 피혁 전문 연구소 및 약품회사, 피혁 업체가 공동으로 대응하여 기술 개발 및 진단, 친환경 약품을 개발하고자 노력하고 있으며 본 연구는 청정 피혁 생산을 위한 저크롬 탄닝 공정 기술 보급 사업을 통하여 환경 문제의 해결하기 위하여 진행되었다. 특히 폐수나 고형폐기물의 형태로 존재하는 크롬의 처리에 환경적, 경제적 문제점으로 인해서 크롬을 적게 사용하는 저크롬 유제 공정과 크롬의 사용을 완전히 배제한 비크롬 유제 공정 기술을 대표적인 4개의 대상기업을 선정하여 기술 이전을 실시한 대표적인 친환경 제혁 기술을 소개 하고자 한다. 아울러 경량성 피혁 소재의 개발을 위해서 비금속을 이용하는 연구를 진행하고 있다.

• 대한기계학회논문집A
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• 제30권6호
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• pp.670-677
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• 2006

Vacuum interrupters are used in various switch-gear components such as circuit breakers, distribution switches, contactors. The electrodes of a vacuum interrupter are manufactured of sinter-forged Cu-Cr material for good electrical and mechanical characteristics. Since the closing velocity is 1-2m/s and impact deformation of the electrode depends on the strain-rate at the given velocity, the dynamic material property of the sinter-forged Cu-Cr alloy is important to design the vacuum interrupter reliably and to identify the impact characteristics of a vacuum interrupter accurately. This paper is concerned with the dynamic material properties of sinter-forged Cu-Cr alloy for various strain rates. The amount of chrome is varied from 10 wt% to 30 wt% in order to investigate the influence of the chrome content on the dynamic material property. The high speed tensile test machine is utilized in order to identify the dynamic property of the Cu-Cr alloy at the intermediate strain-rate and the split Hopkinson pressure bar is used at the high strain-rate. Experimental results from both the quasi-static and the high strain-rate up to the 5000/sec are interpolated with respect to the amount of chrome in order to construct the Johnson-Cook and the modified Johnson-Cook model as the constitutive relation that should be applied to numerical simulation of the impact behavior of electrodes.

• 열처리공학회지
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• 제19권4호
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• pp.200-207
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• 2006

In addition to the basic properties of the base and top coating agents, corrosion resistance of non-chrome magni 565 coating and characteristics of coating film when coated to steel substrate were studied. The system had a good wettability at room temperature. Moreover, both the contact angle and surface tension were affected little by the viscosity of coating agent and surface roughness of the steel substrate. And the samples coated with optimal conditions showed a great corrosion resistance in salt spray test with 1500 hours or longer of initial appearance time of rust. The coating film was composed of overlapping layer of zinc and aluminium flakes, and the thickness of base coat increased with an increase of base coat viscosity. Based on the C-F peaks of 1,1-Difluoroethaen homo-polymer, it was thought that the base coat was an inorganic polymer bond layer. Meanwhile, the top coat showed C-F peaks of polytetrafluoroethylene with C-H peaks of phenol in FT-IR analysis. From the lower weight loss of base coat in TG analysis, it was thought that cross linking density of base coat was larger than that of top coat. It was thought that the small exothermic reactions observed in DSC curves were due to the thermosetting resins contained in the coating agents. Compared to the non-coated specimen, the coated sample showed more higher polarization resistance and corrosion potential with lower corrosion current density.

• 임산에너지
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• 제22권2호
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• pp.36-43
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• 2003

본 연구는 현재 고궁이나 사찰 등지에서 사용되고 있는 단청안료의 방부·방미·방의 효력을 평가하기 위하여 실시하였다. 포리졸과 젤라틴 두 종의 교착제와 석간주, 장단, 삼홍주, 석황, 백분, 군청, 하엽, 수흑, 뇌록, 금진주박 및 호분을 공시안료로 한 실험에서 각 안료의 방부·방미 효력은 교착제의 종류에 의해 효력의 차이가 크게 나타났다. 포리졸을 교착제로 사용시 삼홍주는 부후개떡버섯 및 구름버섯에 대한 방부효력치가 70이상으로 방부성능 기준에 가장 근접하였으며, 장단 처리재가 P. funiculosum, T. viride, R. nigricans에 대해, 군청 처리재가 T. viride에 대하여 우수한 방미효력을 나타냈으나 그 외 안료의 효력치는 떨어지는 것으로 나타났다. 흰개미 실험에 있어서도 교착제에 따른 차이는 있었으나 하엽 및 석황의 처리재가 방의효력이 우수한 것으로 나타났다.

• 한국염색가공학회지
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• 제3권2호
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• pp.10-15
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• 1991

This study was to examine the anti-bacteria effect and the changes of chemical properties of chrome-tanned garment leathers on the preservative treatment. Various test methods, such as investigation of preservative treatment process, resistance test and chemical analysis by cleaning, antbbacterial test by shake flask method are carried out in this study. The results can be obtained as follows: 1. Bacterial reduction percentage of chrome-tanned garment leathers on the preservative treatment was 28.6%. 2. In the antbbacterial effect by dry cleaning, preservative treated leathers has no resistance. 3. Fats content has been removed by dry cleaning using perchloroethylene, so garment leathers properties were altered. 4. PH value was changed by dry cleaning. But once after fats removing, it was changed the little by dry cleaning numbers.

• 한국산학기술학회논문지
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• 제4권3호
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• pp.317-321
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• 2003

우리가 타자기로 글을 쓸 때는 먹지리본을 햄머가 가격하여 종이 위에 글씨 형태의 먹이 묻는 원리로 진행된다. 이러한 원리를 미세 패터닝에 응용하여, 해머 역할을 하는 Nd-YAG 레이저로 유리기판/ 100 ㎚ Cr(먹지)// 실리콘기판(종이)구조의 적층물에 조사시켜 Cr이 실리콘기판 위에 전사됨으로써 미세 패터닝이 가능한지 확인하였다. 제안된 미세 패터닝은 TeraBit/in²급 고밀도 정보저장 또는 반도체 공정의 생산성 향상을 위해 응용이 가능하다. 선폭 50 ㎛급 레이저를 주사속도 200과 1500 ㎜/s Q-스위치 조건을 10,000-50,000 Hz로 변화시키며 마킹을 실시한 결과 Cr의 전사는 진행되지 않았으나, 최종적으로 입사 선폭의 33％ 이하로 마킹이 가능하여 비싼 광학계를 가진 레이저를 대치하여 보다 정밀한 마킹이 가능함을 확인하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1450-1454
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• 2007

A Contact-type Linear Encoder-like Capacitive Displacement Sensor (CLECDiS) has been developed to measure displacements at high accuracy within a long measurement range. In this paper, we have worked on improving the performance and reliability of the sensor. The performance increase can be done by introducing the smaller electrode patterns of $4{\mu}m$ width. In order to improve the reliability of the sensor we have changed the electrode layers from chrome-gold to chrome-gold-chrome and re-design its supporting structure. The newly-designed sensor is fabricated and tested to show that its sensitivity is $35pF/{\mu}m$, which implies that its resolution may be 0.36nm if SNR (Signal-to-Noise-Ratio) is 80.1dB. It is about ten times of that $(3.14pF/{\mu}m)$ of its previous version with 10${\mu}m$ electrodes. The total measurement range remains the same as the previous one; 15mm. The calibration experiments show its improved performance and reliability.

• 소성∙가공
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• 제18권4호
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• pp.310-316
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• 2009

Micro lens array(MLA) is widely used in information technology(IT) industry fields for various applications such as a projection display, an optical power regulator, a micro mass spectrometer and for medical appliances. Recently, MLA have been fabricated and developed by using a reflow method having the processes of micro etching, electroplating, micro machining and laser local heating. Laser thermal relaxation method is introduced in marking of microdots on the surface of densified glass. In this paper, we have proposed a new direct fabrication process using UV laser local thermal-expansion(UV-LLTE) and investigated the optimal processing conditions of MLA on the surface of negative photo-resist material. We have also studied the 3D shape of the micro lens obtained by UV laser irradiation and the optimal process conditions. And then, we made chrome mold by electroplating. After that, we made MLA using chrome mold by hot embossing processing. Finally, we have measured the opto-physical properties of micro lens and then have also tested the possibility of MLA applications.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.316-321
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• 2000

The role of fatigue on the surface damage of 5% chrome cold milling work roll is evaluated. Uniaxial and torsional fatigue tests are carried out, and the baseline data for fatigue life evaluation are established. An appropriate multiaxial fatigue parameter is developed from the fatigue data. Fatigue tests are also performed under compressive mean stresses, and a mean stress model is formulated. A computer program is developed to assess the interaction of fatigue and grinding of the roll. The fatigue damage is computed for selected servicing conditions. It is found that the fatigue damage can be an important issue when the effect of mean stress is ignored, however the fatigue damage is negligibly small when the effect of mean stress including the residual stresses currently used is fully accounted. The result indicates that spalling due to the growth of thermal shock cracks is more important than fatigue damage in roll surface failure.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
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• pp.55-56
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• 2000

We report the fabrication of carbon nanostureture films with excellent electron-emission characteristics on chrome electrodes using a pre-deposited transition metal catalyst layer. The emission current densities of 1 ${\mu}A/cm^2$ and 1 $mA/cm^2$ were measured at the electric field of 2.5 and 4.8 $V/{\mu}m$, respectively, and the current fluctuation of less than 2.5% was observed at the average current density 211 ${\mu}A/cm^2$ for the measurement duration of 20 minutes. We counted more than ${\sim}10^4$ emission sites per $cm^2$ from the emission images, and also noticed good mechanical stability. Moreover, we were able to fabricate good electron-emitting carbon films on chrome electrodes on Corning glass substrates at the nominal temperature below $650^{\circ}C$.