• 생태와환경
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• 제54권3호
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• pp.199-208
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• 2021

메타바코딩을 이용한 환경 DNA 분석은 검출 감도가 높아 어류의 생물다양성 평가 및 멸종위기종의 검출에 유용한 기술이다. 이번 연구는 메타바코딩을 이용해 우리나라 담수어류를 대상으로 높은 검출 효율을 보일 수 있는 적합한 분석방법을 확인하기 위해 4가지 분석조건별, 즉 필터(cellulose nitrate filter, glass fiber filter), 추출 키트(DNeasy^® Blood & Tissue Kit, DNeasy^® PowerWater Kit), 프라이머 조합(12S rDNA, 16S rDNA) 그리고 PCR 방법(conventional PCR, touchdown PCR)로 나타나는 Operational Taxonomic Units(OTUs) 수와 종 조성을 비교하였다. Glass fiber filter와 DNeasy^® Tissue & Blood Kit를 이용해 추출한 시료는 12S rDNA와 16S rDNA 프라이머 조합에서 담수어류 OTUs가 가장 많이 검출되었다. 모든 분석조건 중 프라이머 조합에서만 조기어강(Class Actinopterygii) 평균 OTUs 수에서 통계적으로 유의한 차이를 보였고(Non-parametric Wilcoxon Signed Ranks Test, p=0.005), 담수어류 평균 OTUs 수는 유의하지 않았다. 종 조성 비교 결과 역시 프라이머 조합에서 유의한 차이를 보였고(PERMANOVA, Pseudo-F=6.9489, p=0.006), 나머지 분석조건에서는 유의한 차이를 보이지 않았다. NMDS 분석 결과 종 조성은 유사도 65% 기준에서 프라이머 조합에 따라 묶였고, 16S rDNA 프라이머 세트는 주로 멸종위기종인 모래주사(Microphysogobio koreensis), 꼬치동자개(Pseudogobio brevicorpus)가 기여하였고, 12S rDNA 프라이머 세트는 주로 일반종인 피라미(Zacco platypus), 꺽지(Coreoperca herzi) 등이 기여한 것으로 나타났다. 본 연구는 국내 하천에서 채취한 시료에 대한 메타바코딩을 이용한 종 다양성 분석의 기초정보를 제공한다.

• 한국임상수의학회지
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• 제24권4호
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• pp.577-583
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• 2007

It is important to obtain semen with good quality for efficient fertilization and pregnancy. To obtain these semen, various methods have been developed but most of these methods are time consuming and require costly equipment. Therefore, the objective of this research is to investigate the usability of column filtration system as quick and simple method to get sperm with better quality. Ejaculates were obtained from 5 dogs and analyzed with basic quality parameters before each filtration. Sperm concentration was adjusted to $5{\times}10^7/ml$ after dilution. The experimental groups were divided into non-filtered group(control) and filtered groups(glass wool, Sephadex 5% and Sephadex 20%). Ejaculates were filtered through each filter system and assessed by recovery rate of sperm, motility, normal morphology, CFDA/PI stain and plasma membrane integrity(hypo-osmotic swelling test, HOST). The lowest recovery rate of spermatozoa was recorded in glass wool filtration group, followed by 20% Sephadex filtration group(p<0.05). There was no significant difference between control(non-filtered) and 5% Sephadex filtration poop. Also, there was no significant difference of sperm motility assessed under light microscope among experimental groups. Morphological normality of canine spermatozoa was the highest in the glass wool filtration group and the lowest in the 5% Sephadex filtration group with no significant differences versus 20% Sephadex filtration and control group, respectively(p<0.05). Viability of canine sperm assessed by CFCA/PI staining was the highest in the glass wool filtration poop with no significant difference versus the control group, and the lowest in the 20% Sephadex filtration group with no significant difference versus 5% Sephadex filtration group, respectively(p<0.05). HOS values of canine sperm was the highest in the 20% Sephadex filtration group with no significant difference versus 5% Sephadex filtration group, and the lowest in the control poop with no significant difference versus glass wool filtration group, respectively(p<0.05). Therefore, these results indicated that filtration treatment for extended canine sperm would be useful method to get sperm with better quality by trapping the damaged sperm, consequently filter would be physical barrier against injured or immotile sperm.

• Tribology and Lubricants
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• 제35권2호
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• pp.106-113
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• 2019

We investigated the application of tetrahedral amorphous carbon (ta-C) coatings to fabricate a glass lens manufactured using a glass molding process (GMP). In this work, ta-C coatings with different thickness (50, 100, 150 and 200 nm) were deposited on a tungsten carbide (WC-Co) mold using the X-bend filter of a filtered cathode vacuum arc. The effects of thickness on mechanical and tribological properties of the coating were studied. These ta-C coatings were characterized by atomic force microscopy, scanning electron microscopy, nano-indentation measurements, Raman spectrometry, Rockwell-C tests, scratch tests and ball on disc tribometer tests. The nano-indentation measurements showed that hardness increased with an increase in coating thickness. In addition, the G-peak position in the Raman spectra analysis was right shifted from 1520 to $1586cm^{-1}$, indicating that the $sp^3$ content increased with increasing thickness of ta-C coatings. The scratch test showed that, compared to other coatings, the 100-nm-thick ta-C coating displayed excellent adhesion strength without delamination. The friction test was carried out in a nitrogen environment using a ball-on-disk tribometer. The 100-nm-thick ta-C coating showed a low friction coefficient of 0.078. When this coating was applied to a GMP, the life time, i.e., shot counts, dramatically increased up to 2,500 counts, in comparison with Ir-Re coating.

• 한국생산제조학회지
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• 제22권4호
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• pp.635-642
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• 2013

We have prepared a DEMO conveyor device for conveying a large 8G class glass sheet using ahorizontal air-cushion system. This device consists of the body frame and the driving frame that are combined to realize a frame for conveying glass without any contact.The driving frame comprises an air flotation table (bed), drive roller supported at both ends, and ASU. Part of the ASU serves to control the airflow as the chamber consists of a porous pad and fan. Fiber filters replace the porous pad and axial fans serve as an air compressor. In addition, to determine the appropriate glass levitation from the air table, this study examined the design specifications of the applied filter (discharge speed of HEPA and ULPA filters, and flow rate) as well as the height of the and the proper supporting roller height (14mm). Then, after adjusting the position of the ASU and the number of ASUs required to configure the UNIT air floating C/V, we analyzed the height and flatness of the glass and derived the appropriate layout (1140-mm distance between ASUs).

• 한국산학기술학회논문지
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• 제10권1호
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• pp.6-11
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• 2009

본 논문에서는, 청정지역내에서 다수의 유리 기판을 적재하여 반송하는 롤러 컨베이어 시스템에서, 롤러와 카세트 사이의 기계적 마찰로 인해 발생하는 오염입자에 의한 유리 기판의 오염여부를 판단하기 위해, 시스템 내부의 유동장을 전산유체역학 기법을 통해 해석하였다. 수치해석 결과 일정 속도로 이동하는 카세트 하부에 큰 와류가 생성되는 것을 확인하였다. 그러나 이 와류는 후면에서 유입되는 강한 기류와, 상부 FFU에서 공급되어 하부로 배기되는 기류로 인해, 카세트의 하부 영역에만 갇히게 되는 것으로 나타났다. 따라서 카세트와 롤러 사이의 기계적 마찰로 인해 오염입자가 발생하여도 상부로 이동할 수 없어 유리 기판의 오염 가능성은 낮았다. 또한 이동속도가 빨라짐에 따라 유리 평판 사이의 공기 유동의 방향이 평판의 점성 전단력에 의해 역방향으로 바뀌게 됨을 확인하였다.

• 한국환경보건학회지
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• 제22권2호
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• pp.32-42
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• 1996

This study was performed to evaluate accuracy and precision of filter method and impinger method for analyzin airborne isocyanates in mixture (2, 6-TDI, HDI, 2, 4-TDI, MDI). Filter method was performed using the OSHA Method 42 and impinger method using the NIOSH Method 5521. The samples were analyzed by high performance liquid chromatography-ultraviolet detector (HPLC-UVD). After the optimum operating conditions for each method were investigated, samples with various concentration levels were quantified at the conditions. The precision was expressed by the pooled coefficient of variation(C.V.) and the accuracy by overall accuracy. The results are summarized as follows: 1. The optimum condition of filter method was determined at 35/65 ACN/buffer (0.01 M ammonium acetate) in mobile phase. And in case of impinger method, it was at 30/70 ACN/buffer(0.2 M sodium acetate). The effect of concentrations of acetate on the separation of the peaks was not significant, but, the effect of ACN/buffer ratio was significant. 2. The correlation coefficients for the two methods were above 0.9 in all isocyanate compounds. Average recovery efficiencies for 2, 6-TDI, HDI, 2, 4-TDI and MDI in filter method were 92.4%, 102.6%, 87.3% and 101.0%, respectively. Those in impinger method were 106.6%, 106.7%, 99.0% and 103.6%, respectively. As a result, the recovery efficiency of impinger method was higher than those of filter method in analyzing isocyanate compounds. 3. The pooled coefficients of variations of the methods were slightly higher than expected. The overall accuracies of the methods were within $\pm 25%$ for each isocyanate compound. Since these results satisfy NIOSH criteria, the accuracy of the experiment is appropriate. 4. As seen above, impinger method is more efficient than filter method. But, there are many disadvantages in impinger method. Therefore, solid sorbent such as a glass fiber filter must be developed in order to have the high efficiency not less than that of impinger method in the future.

• 한국광학회지
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• 제17권3호
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• pp.285-289
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• 2006

광섬유형 콜리메이터와 광 진행 경로의 수직 방향으로 삽입된 주기적으로 식각된 줄무늬(stripe) 평판에 의해 진행하는 빔의 일부에 광 경로차를 유도하는 마이크로 옵틱형 마하젠더 간섭형 필터를 제안하고 구현하였다. 제안된 마이크로 옵틱 필터는 주기적으로 식각된 줄무늬(stripe) 구조의 평판을 빔 경로에 삽입하여 측방향 정렬에 무관하게 특정 소멸비 값 이상의 특성을 구현할 수 있으며, 식각된 박막의 두께를 조정함으로써 원하는 대역폭 및 주기의 전달특성을 가지는 필터를 구현할 수 있다. 네거티브 포토레지스터인 SU-8을 기반으로 줄무늬(stripe) 구조의 주기적으로 식각된 평판을 제작하였으며 이를 이용하여 구현된 필터의 소멸비는 측방향 정렬에 무관하게 30 dB이상의 값을 가진다. 제작된 필터의 FSR(Free Spectral Range)은 장파장 대역에서 약 237 nm이고 그리고 삽입손실은 2 dB 미만의 값을 가진다. 통과대역에서의 PDL(Polarisation Dependent Loss)값은 0.15 dB 미만이다.

• 한국재료학회지
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• 제19권12호
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• pp.657-660
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• 2009

Optical characteristics and structural changes depending on CuO content in phosphate glasses that are used in near-infrared (near-IR) filters were investigated. With phosphate glasses that contain 1-9 mol% CuO, changes in optical transmittance, optical absorption, and color coordinate were measured with a UV-VIS spectrophotometer. An XPS (X-ray photoelectron spectroscopy) analysis was performed to determine valence of copper ion that influences optical characteristics in near-IR filter glasses. Structural changes in glasses depending on CuO content were also analyzed by FT-IR (Fourier transform infrared) and Raman spectrophotometers. From the UV-VIS spectrophotometer results, strong absorption peaks at 220 & 900 nm were found and transmittance was decreased. The color coordinates of the glasses were shifted to the green color direction with CuO addition for increasing absorption of long wavelength range spectra, in spite of the amount of $Cu^{2+}$, which gives a blue color to glasses, and which was increased in XPS results. Also, structural de-polymerization of glasses with CuO addition were found by FT-IR and Raman results.

• Journal of Biosystems Engineering
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• 제32권4호
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• pp.263-268
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• 2007

An auto sampling and filtering unit was developed for monitoring automation of a fermentation process and its performance was evaluated. The automatic sampling and filtering unit was constructed with a glass filter, a diaphragm suction pump, and a flow direction change valve. To evaluate operating stability, delivery volumes of the suction pump were measured according to the experimental conditions of cellulose powder, pore size of the glass filter and suction head of the pump. The developed unit could deliver the sample solution under any experimental conditions except the filter pore size of $16{\mu}m$ and the suction head of 20cm. In case of the suction head of 30cm, the pump could not deliver the sample solution at all. Concentrations of the sample solutions were converged on those of the standard glucose solution after 8 minutes from the initial sampling time. The relative error of concentration between the sample and the standard solution showed 3.8, 4.8, 7.0% for the 1, 3, 5% contents of cellulose powder, respectively.

• 대한기계학회논문집A
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• 제28권9호
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• pp.1429-1434
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• 2004

Immunoassay is one of the important analytical methods for clinical diagnoses and biochemical studies, but needs a long time, troublesome procedures and expensive reagents. In this study, therefore, we propose the micro filter chip with microbeads for immunoassay, which has pillar structures. The advantage of the proposed micro filter chip is to use simple fabrication process and cheap materials. The mold was made by the photolithography technique with Si wafer and negative photoresist SU-8. The replica was made of PDMS, bonded on the pyrex glass. The micro filter chip consists of inlet channel, filter chamber and outlet channel. HBV (Hepatitius B virus) monoclonal antibody (Ag1) labeled with biotin were immobilized onto streptavidin coated beads of 30∼50 $\mu$m size. Fluorescein isothiocyanate (FITC)-labeled HBV monoclonal antibody (Ag8) was used to detect HBsAg (Hebatitis B virus surface Antigen), and fluorescence intensity was monitored by epi-fluorescence microscope. In this study, the immune response of less than 30 min was obtained with with the use of 100 $m\ell$ of sample.