• Asian Journal of Atmospheric Environment
• /
• 제11권1호
• /
• pp.54-60
• /
• 2017

Quantifying the trace elements in infinitesimal ambient liquid samples (e.g., single raindrop, cloud/fog water, and the soluble fraction extracted from the particles collected for a short time) is an important task for understanding formation processes, heating/cooling rates, and their health hazards. The purpose of this study is to employ an in-air micro PIXE system for quantitative analysis of the trace elements in a thimbleful of reference liquid sample. The bag type liquid sample holder originally designed with $10{\mu}m$ thick $Mylar^{(R)}$ film retained the original shape without any film perforation and apparent peaks of film blank by the end of the analysis. As one of tasks to be solved, the homogeneity of the elemental distribution in liquid reference species was verified by the X-ray line profiles for several references. It was possible to resolve the significant peaks for whole target elements corresponding to the channel number of micro-PIXE spectrum. The calibration curves for the six target elements (Si, S, Cl, Fe, Ni, and Zn) in standard solutions were successfully plotted by concentration (ppm) and ROI of interest net counts/dose (nC).

• Journal of Magnetics
• /
• 제18권3호
• /
• pp.308-310
• /
• 2013

Translation induced by the field-gradient force is being observed for a single ferromagnetic iron grain and a ferrimagnetic grain of a ferrite sample ($CuFe_2O_4$). From measurements on the translation, precise saturated magnetization of $M_S$ is possible for a single grain. The method is based on the energy conservation rule assumed for the grain during its translation and the grain is translated through a diffuse area under microgravity conditions. The results of the two materials indicate that a field-induced translation of grain bearing spontaneous moment is generally determined by a field-induced potential $-mM_SH(x)$ where m denotes the mass of sample. According to the above translations, the detection of $M_S$ is not interfered by any signals from the sample holder. The $M_S$ measurement does not require m value. By observing translations resulting from fieldinduced volume forces, the magnetization of a single grain is measurable irrespective of its size; the principle is also applicable to measuring susceptibility of diamagnetic and paramagnetic materials.

• 지구물리
• /
• 제2권4호
• /
• pp.269-276
• /
• 1999

암석의 코어비저항 값을 올바르게 결정하기 위한 노력의 일환으로 비저항 측정에 있어서 샘플홀더의 영향을 분석하고 시계열자료로부터 암석의 비저항을 대표할 수 있는 비저항 값을 효과적으로 구하는 방안에 관하여 연구하였다. 샘플홀더에 대한 연구로는 기존의 GS식과 2전극식 방법과 함께 코어시료 표면을 전도성 접착제로 처리한 변형 GS식 및 변형 2전극식을 고안하여 각 특성을 비교하였으며 그 중에서 변형 2전극식이 측정자료의 안정성과 측정의 편이성 측면에서 장점이 있는 것으로 확인되었다. 샘플홀더 및 사용 소스 주파수의 차이에 따라 달리 나타나는 시계열자료의 분포특성에 관한 분석 결과는 최대곡률점을 이용하여 암석의 대표비저항을 결정하는 방법이 효과적임을 보이고 있다.

• 한국농업기계학회:학술대회논문집
• /
• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.II
• /
• pp.210-218
• /
• 2000

Since the SSC(soluble solid contents) and titratable acidity of fruit are highly concerned to the taste, the need for measuring them by non-destructive technology such as NIR(Visual and Near-infrared) spectroscopy is increasing. Specially, in order to grade the quality of each fruit with a sorter at sorting and packing facilities, technologies for online measurement satisfying the tolerance in terms of accuracy and speed should be developed. Many researches have been done to develop devices to measure the internal qualities of fruit such as SSC, titratable acidity, firmness, etc. with the VIS(Visual)/NIR(Near Infrared) reflectance spectra. The distributions of the SSC, titratable acidity, firmness, etc. are different with respect to the position and depth of fruit, and generally the VIS/NIR light can interact with fruit in a few millimeters of pathlength, and it is very difficult to measure the qualities of inner flesh of fruit. Therefore, to measure the average concentrations of each quality factor such as SSC and titratable acidity with the reflectance-type NIR devices, the spectra of fruit at several positions should be measured. Recently, the interest about the transmittance-type VIS/NIR devices is increasing. NIR light can penetrate through the fruit about 1/10-1/1,000,000 %. Therefore, very intensive light source and very sensitive sensor should be adopted to measure the transmitted light spectra of intact fruit. The ultimate purpose of this study was to develop a device to measure the transmitted light spectra of intact fruit such as apple, pear, peach, etc. With the transmittance-type VIS/NIR device, the feasibility of measurement of the SSC and titratable acidity in intact fruit cultivated in Korea was tested. The results are summarized as follows; A simple measurement device which can measure the transmitted light spectra of intact fruit was constructed with sample holder, two 500W-tungsten halogen lamps, a real-time spectrometer having a very sensitive CCD array sensor and optical fiber probe. With the device, it was possible to measure the transmitted light spectra of intact fruit such as apple, pear and peach. Main factors affecting the intensity of transmitted light spectra were the size of sample, the radiation intensity of light source and the integration time of the detector. Sample holder should be designed so that direct light leakage to the probe could be protected. Preprocessing method to the raw spectrum data significantly influenced the performance of the nondestructive measurement of SSC and titratable acidity of intact fruit. Representative results of PLS models in predicting the SSC of peach were SEP of 0.558 Brix% and R2 of 0.819, and those in predicting titratable acidity were SEP of 0.056% and R2 of 0.655.

• Applied Microscopy
• /
• 제47권3호
• /
• pp.208-213
• /
• 2017

The microstructural changes in Co nanoparticles and an Au-10at.%Pd thin film have been investigated using an in situ heating holder with a micro-electro-mechanical system (MEMS). In Co nanoparticles, two phases (face-centered cubic and hexagonal close-packed crystal structures) were found to coexist at room temperature and microstructures at temperatures, higher than $1,000^{\circ}C$, were observed with a quick response time and significant stability. The actual temperature of each specimen was directly estimated from the changes in the lattice spacing (Bragg-peak separation). For the Au-10at.%Pd thin film, at a set temperature of $680^{\circ}C$, the actual temperature of the sample was estimated to be $1,020^{\circ}C{\pm}123^{\circ}C$. Note that the specimen temperature should be carefully evaluated because of the undesired effects, i.e., the temperature non-uniformity due to the sample design of the MEMS chip, and distortion due to thermal expansion.

• 한국초전도ㆍ저온공학회논문지
• /
• 제14권4호
• /
• pp.12-15
• /
• 2012

$MgB_2$ superconductor is highly sensitive to the Mg content. Even if the samples are synthesized with the appropriate looking stoichiometric ratio, the heat treatment leads to the loss of Mg either to ambiance or to MgO. To avoid it, either excess Mg is added in the starting powder or sealed ampoule annealing is employed. In this paper the effect of open Mg sintering ambiance on the ex-situ $MgB_2$ was studied to enhance its superconducting properties. The open Mg ambiance was created to avoid any overpressure of Mg by providing a hole in Fe tube used as sample holder. The decrease in resistivity of the synthesized sample was observed through the increased temperature dependence of electron-phonon interactions. A clear enhancement in the superconducting cross-sectional area and hence the in-field critical current density is obtained.

• 한국산림과학회지
• /
• 제90권6호
• /
• pp.788-791
• /
• 2001

본 연구는 기존의 토양 코어 시료 채취기 (double-cylinder hammer-driven soil core sampler)를 개량하여 원하는 토양 깊이에서 자연상태의 토양 코어 시료를 쉽고 편리하게 채취하여 운반, 보관할 수 있는 새로운 도구를 제시하기 위하여 수행되었다. 본 연구에서 제시된 도구와 이전에 일반적으로 사용되던 채취기와의 차이점은 1) 해머가 본체로부터 분리되고, 2) 내부 실린더가 2개로 분할되며, 3) 플라스틱 시료 보관통을 사용하도록 한 것 등이다. 본 도구는 적습한 산림토양을 대상으로 이용하는 것이 효과적이며, 해머 사용 전에 토양 시료의 압축을 줄이기 위하여 시료 채취기를 가능한 손으로 깊게 토양에 삽입한 후 해머 작업을 실시하는 것이 바람직할 것으로 생각된다. 본 도구는 채취된 토양 층위와 부피가 원래 토양과 같은 상태로 유지되는 깊이 40cm, 직경 5cm의 코어 시료 채취에 적합한 것으로 판단된다.

• 한국환경보건학회지
• /
• 제35권2호
• /
• pp.130-142
• /
• 2009

This study compared FTIR with XRD method for the analysis of quartz by % recovery, coefficient of variation (CV) and influence of the interference. the results were as the following. 1. In FTIR method, the coefficient of determination ($r^2$) was 0.9998 in a calibration curve of $695\;cm^{-1}$, and the limit of detection was $4.9{\mu}g/sample$. 2. The highest recovery was $799\;cm^{-1}$ (98.2%). 3. The CVpooled of the FTIR method was approximately 10% in three wave numbers. 4. The analysis of qualitative and quantitative for quartz is difficult with mixed cristobalite and iron oxide. 5. In XRD method with rotating sample holder and LynxEye detector, the coefficient of determination was 0.9996 in a calibration curve, and the limit of detection was $5.9{\mu}g/sample$. 6. The recovery and CV pooled were 104.3%, and 11 %, respectively. 7. In muffle furnace ashing, the quartz weight decreased to 34% when the maximum weight of the iron oxide was more than eight times. In conclusion, the accuracy (% recovery) and precision (CV) of FTIR and XRD method for analyzing $\alpha$-quartz were similar. FTIR method was a disadvantage for sample matrix because it indicates possibility of interference. However, XRD method distinguished specific crystalline forms of silica, and the majority of silicate minerals. In addition, XRD method recommend filter dissolution to pretreatment method.

• 구강회복응용과학지
• /
• 제36권1호
• /
• pp.55-60
• /
• 2020

물리적 항균효과를 나타내는 4차 암모늄 화합물을 치과 진료실 미생물 주요 오염 구역에 도포 후 시기별 오염도의 변화를 측정하고자 하였다. 4개의 국내외 치과병의원에서 미생물 감염이 쉬운 유닛체어 핸들, 타구대 표면, 핸드피스 거치대 등에 ATP (adenosine triphosphate) 모니터링 시스템과 ATP 표면검사 테스트 키트를 사용하여 항균제 도포 전과 후 시기별 오염도를 비교 측정하였다. 4차 암모늄 화합물 도포 전 구역별 미생물 오염도는 치과의사가 주로 사용하는 핸드피스 거치대가 가장 높았다. 도포 후 시기별 오염도의 변화를 분석한 결과 대부분의 진료실에서 현저한 오염도의 감소를 보였으며, 대략 4-6개월 정도 효과가 지속되는 양상을 보였다. 항균효과의 지속성과 최소량의 화학성분 노출이라는 장점으로 향후 대단위 후속연구를 통해 4차 암모늄 화합물이 치과 진료실에서 효과적으로 사용될 수 있을 것으로 기대된다.

• Journal of Biosystems Engineering
• /
• 제24권2호
• /
• pp.123-134
• /
• 1999

The electrical properties such as dielectric constant, dielectric loss factor and AC conductivity of grain were presented to measure the moisture content of grain using RF impedance. At frequency ranging from 1 to 10MHz and room temperature, $20^{\circ}C$, vector network analyzer(HP4195) and coaxial type sample holder were used to analyze the electrical properties of paddy(11∼24%w.b.), brown rice(11∼18%w.b.), barley(11∼21%w.b.) and wheat(11∼23%w.b.) depending on the moisture content, frequency and bulk density. The dielectric constant and AC conductivity of grain samples increased with moisture content and bulk density. The dielectric constants decreased with frequency and could be expressed as function of the moisture density(decimal moisture $content{\times}bulk$ density).