• Geomechanics and Engineering
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• 제14권2호
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• pp.131-139
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• 2018

The preparation of repeatable and uniformly reconstituted soil specimens up to the specified conditions is an essential requirement for the laboratory tests. In this study for large samples replication, the simultaneous usage of the traveling pluviation and curtain raining technique is used to develop a new method, called the curtain travelling pluviator (CTP). This simple and cost effective system is based on the air pluviation approach, whilst reducing the sample production time, can reproduce uniform samples with relative densities ranging from 25% to 96%. In order to investigate the resulting suitability and uniformity from the proposed method, a series of tests is performed. The effect of curtain traveling velocity, curtain width, drop height, and flow rate on the parameters of the sample is thoroughly investigated. Increase in the curtain velocity and drop height leads to the increase in relative density for the sand specimen. Increase in curtain width typically resulted in the reduction of relative density. Test results reveal that the terminal drop height for the sand specimen in this study is more than 500 mm. Relative density contour lines are presented that can be utilized in optimizing the drop height and curtain width parameters. Sample uniformity in the vertical and horizontal orientation is investigated through the sampling containers. Increasing relative density tends to result in the higher sample repeatability and uniformity.

• 한국전자현미경학회:학술대회논문집
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• 한국현미경학회 1999년도 제30차 춘계학술대회
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• pp.53-56
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• 1999

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2002년도 마이크로/바이오 가시화기술부문 학술강연회
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• pp.85-99
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• 2002

• 한국산학기술학회논문지
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• 제13권3호
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• pp.955-960
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• 2012

본 연구는 순수 Polyurethane과 일반적인 난연제인 $Al(OH)_3$ 및 $Mg(OH)_2$를 첨가한 sample과 Cloisite Na+, Cloisite 15A를 첨가한 sample의 난연성 및 기계적 특성을 비교하였다. 또한 Sodium silicate와 Polyurethane을 혼합한 것에 경량성 충진제인 Vermiculite, Perlite를 충진한 sample의 난연성 및 기계적 특성을 확인하였다. 그 결과, Cloisite Na+와 Cloisite 15A를 첨가한 sample과 Sodium silicate를 혼합한 sample에서 난연제를 첨가한 것과 같은 등급의 난연성을 확인하였다. 인장강도는 filler의 양이 증가함에 따라 저하 되었으나, sodium silicate를 첨가한 sample의 경우 다른 sample 보다 강도가 향상됨을 확인하였다.

• Fibers and Polymers
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• 제3권3호
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• pp.97-102
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• 2002

A series of waterbome poly(urethane-urea) anionomers were prepared from isophorone diisocyanate (IPDI), polycaprolactone diol (PCL), dimethylol propionic acid (DMPA), ethylene diamine (EDA), and triethylamine (TEA), NaOH, or Cu($(COOCH_3)_2$) as neutralizing agent. This study was performed to decide the effect of neutralizing agent type on the particle size viscosity, hydrogen bonding index, adhesive strength, antistaticity, antibacterial and mechanical properties. The particle size of the dispersions decreased in the following order: TEA based samples (T-sample), NaOH based samples (N-sample), and Cu($(COOCH_3)_2$) based sample (C-sample). The viscosity of the dispersions increased in the order of C-sample, N-sample, and T-sample. Metal salt based film samples Of and C-sample) had much higher antistaticity than TEA based sample. By infrared spectroscopy, it was found that the hydrogen bonding index (or fraction) of samples decreased in the order of T-sam-pie, N-sample, and C-sample. The adhesive strength and tensile modulus/strength decreased in the order of T-sample, N-sam-pie, and C-sample. The C-sample had strong antibacterial halo, however, T- and N-samples did not

• Fisheries and Aquatic Sciences
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• 제1권2호
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• pp.187-191
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• 1998

Chemotherapy can not be applied for the control of fish viral diseases because viruses depend on host machinery for their replication. Although new control strategies including vaccination are under development, avoidance of virus introduction by rapid and correct diagnosis is the best way of fish viral disease control. Although observation of virus particles with an electron microscope is an easy method for virus detection, it take a few days for the sample preparation. In order to shorten the sample preparation time, microwave radiation was applied in the procedure. With this method, 15 seconds was enough for fixation of virus infected fish samples or cultured cells inoculated with infectious hematopoietic necrosis virus, which takes 2-4 hours with routine methods. Also four minutes was enough for polymerization of embedding resin which takes 24-48 hours with routine methods. Samples prepared with microwave were good enough for direct electron microscopic observation and immunogold labeling assay.

• 암석학회지
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• 제13권3호
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• pp.126-132
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• 2004

이 연구는 저어콘의 아입자분석을 위한 상세한 시료준비방법과 물을 비커에 계속 흘려 가벼운 광물을 범람시키는 간편한 광물분리기술을 제시한다. 이 방법은 월플리테이블의 사용과 중액분리 과정이 필요하지 않아 기존의 분리법보다 빠르고 효율적이며, 특히 소량의 저어콘이 필요한 아입자분석을 위해 적합하다.

• Journal of Magnetics
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• 제19권2호
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• pp.101-105
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• 2014

In this work, Zinc ferrite nanoparticles have been prepared by various methods, conventional (ZC), mechanochemical processing (ZM) and Sol-Gel (ZS) method, to compare their structural and magnetic properties. The cation distribution obtained from XRD shows the degrees of inversions are 4%, 14.8%, and 16.4% from the normal $ZnFe_2O_4$ structure. Fourier transform infrared spectroscopy (FT-IR) confirms changes in cation distribution of $ZnFe_2O_4$ fabricated by sol-gel and mechanochemical processing. The $^{57}Fe$ M$\ddot{o}$ssbauer spectra of the samples were recorded at room temperature. The spectra exhibit a line broadening. The magnetic properties of the samples were studied by vibration sample magnetometer (VSM) at room temperature and the results show that the sample ZM has ferrimagnetic behaviour.

• Bulletin of the Korean Chemical Society
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• 제35권1호
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• pp.69-75
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• 2014

Accurate analysis of fly ash particles is not trivial because of complex nature in physical and chemical properties. SPLITT fractionation (SF) was employed to fractionate the fly ash particles into subpopulations in large quantities. Then the SF-fractions were analyzed by the steric mode of sedimentation field-flow fractionation (Sd/StFFF) for size analysis. The SF-fractions were also analyzed by ICP-OES. The results showed that the fly ash is mainly composed of Fe, Ca, Mg and Mn. No particular trends were observed between the particle size and the concentrations of Fe, Ca, Mg, while Mn, Cu and Zn were in higher concentrations in smaller particles. Sample preparation procedures were established, where the fly ash particles were sieved to remove large contaminants, and then washed with acetone to remove organics on the surface of particles. The sample preparation and analysis methods developed in this study could be applied to other environmental particles.

• 한국연초학회지
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• 제32권2호
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• pp.70-76
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• 2010

A simple and sensitive automatic amino acid analyzer method for the determination of free amino acids in tobacco was described. Sample preparation consisted of a single step of extraction with 0.1 mol HCl at ambient temperature in 60 min by sonication, followed by filtration of an aliquot. Automated amino acid analyzer was used to construct a post-column ninhydrin reaction unit to monitor amino acids separated by liquid chromatography using a series of eluting buffers. By optimization of sample preparation, separation of 19 amino acids was achieved. Limits of quantitation was 0.01 mg/g, coefficients of variation ranged from 0.5 % to 8.9 % and recoveries range from 85 % to 106 %. The method was applied to the analysis of amino acids contents of tobacco leaves in different varieties.