• Journal of Animal Science and Technology
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• 제44권4호
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• pp.459-474
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• 2002

본 연구는 실험방법이 간단하고 분석비요이 저렴하여, 단시간내에 세균수를 측정할 수 있는 현장적용 가능한 방법을 확립하기 위하여 냉장우육의 총균수를 표준평판배양법과 배양온도를 25$^{\circ}C$, 30$^{\circ}C$, 35$^{\circ}C$ 별로 레자주린 환원색과 환원시간을 측정하여 상관관계를 산출하였다. 연구결과를 보면, 총균수(25$^{\circ}C$/72시간, Y)와 레자주린 환원시간(X)과의 상관계수는 RRT(Resazurin reducion test) 배양온도가 25$^{\circ}C$와 30$^{\circ}C$, 환원색은 청색에서 분홍색으로 변할 때가 각각 -0.95와 -0.94로서 가장 높았다. 상관계수와 환원시간을 감안할 때 RRT 배양온도는 30$^{\circ}C$가 적합하였으며, 이때 회귀방정식은 Y=-0.4386X + 7.7870이었으며, 돼지고기의 총균수가 $10^2$, $10^3$, $10^4$ cfu/$cm^2$일 경우 검사시간은 13.2시간, 10.9시간, 8.6시간이었다. 총균수(30$^{\circ}C$/72시간, Y)와 레자주린 환원시간(X)과의 상관계수는 RRT 배양온도가 30$^{\circ}C$, 환원색은 청색에서 분홍색으로 변할 때가 -0.93으로서 가장 높았다. 이때 회귀방정식은 Y=0-0.417X + 7.5540이었으며, 돼지고기의 총균수가 $10^2$, $10^3$, $10^4$ cfu/$cm^2$일 경우 검사시간은 13.3시간, 10.9시간, 8.5시간이었다. 총균수(35$^{\circ}C$/48시간, Y)와 레자주린 환원시간(X)과의 상관계수는 RRT 배양온도가 30$^{\circ}C$, 환원색은 청색에서 분홍색으로 변할 때가 -0.93으로서 가장 높았다. 이때 회귀방정식은 Y=-0.3514X + 6.7513이었으며, 돼지고기의 총균수가 $10^2$, $10^3$, $10^4$ cfu/$cm^2$일 경우 검사시간은 13.5시간, 10.7시간, 7.8시간이었다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2004년도 동계학술대회 논문집
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• pp.7-7
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• 2004

• Carbon letters
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• 제19권
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• pp.72-78
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• 2016

Spinnable pitches and carbon fibers were successfully prepared from petroleum or coal pyrolysis residues. After pyrolysis fuel oil (PFO), slurry oil, and coal tar were simply filtered to eliminate the solid impurities, the characteristics of the raw materials were evaluated by elemental analysis, ¹³C nuclear magnetic resonance spectrometer, matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI-TOF-MS), and so on. Spinnable pitches were prepared for melt-spinning carbon fiber through a simple distillation under strong nitrogen flow, and further vacuum distillation to obtain a high softening point. Carbon fibers were produced from the above pitches by single-hole melt spinning and additional heat treatment, for oxidization and carbonization. Even though spinnable pitches and carbon fibers were processed under the same conditions, the melt-spinning and properties of the carbon fiber were different depending on the raw materials. A fine carbon fiber could not be prepared from slurry oil, and the different diameter carbon fibers were produced from the PFO and coal tar pitch. These results seem to be closely correlated with the initial characteristics of the raw materials, under this simple processing condition.

• Tribology and Lubricants
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• 제35권6호
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• pp.323-329
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• 2019

Sapphire is currently used as a substrate material for blue light-emitting diodes (LEDs). The market for sapphire substrates has expanded rapidly as the use of LEDs has extended into various industries. However, sapphire is classified as one of the most difficult materials to machine due to its hardness and brittleness. Recently, a lap-grinding process has been developed to combine the lapping and diamond mechanical polishing (DMP) steps in a single process. This paper studies, the effect of wafer surface roughness on the chemical mechanical polishing (CMP) process by pressure and abrasive concentration in the lap-grinding process of a sapphire wafer. In this experiment, the surface roughness of a sapphire wafer is measured after lap-grinding by varying the pressure and abrasive concentration of the slurry. CMP is carried out under pressure conditions of 4.27 psi, a plate rotation speed of 103 rpm, head rotation speed of 97 rpm, and slurry flow rate of 170 ml/min. The abrasive concentration of the CMP slurry was 20wt, implying that the higher the surface roughness after lapgrinding, the higher the material removal rate (MRR) in the CMP. This is likely due to the real contact area and actual contact pressure between the rough wafer and polishing pad during the CMP. In addition, wafers with low surface roughness after lap-grinding show lower surface roughness values in CMP processes than wafers with high surface roughness values; therefore, further research is needed to obtain sufficient surface roughness before performing CMP processes.

• 한국대기환경학회지
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• 제28권1호
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• pp.39-51
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• 2012

Aerosol slurry samples were collected in 60-min interval using Korean Semi-continuous Elements in Aerosol Sampler (KSEAS) between May 19 and June 6, 2010 at an urban site of Gwangju. The $PM_{2.5}$ samples were collected with a flow rate of 16.7 L/min and particles are grown by condensation of water vapor in a condenser maintained at ${\sim}5^{\circ}C$ after saturation by direct injection of steam. The resulting droplets are collected in a liquid slurry with a airdroplet separator. Concentrations of 16 elements (Al, Fe, Mn, Ca, K, Cu, Zn, Pb, Cd, Cr, Ti, V, Ni, Co, As, Se) in the collected slurry samples were determined off-line by ICP-MS. KSEAS sample analysis encompassed the sampling periods for which 24-hr average elemental species concentrations were calculated for comparison with those derived from 24-hr integrated filter samples. Relationship between elemental species measured by two methods indicated high correlation coefficients (r), mostly greater than r of 0.80. However, we note that concentrations of Al, K, Ca, Mn, and Fe, which are often associated with crustal elemental particles, in the KSEAS samples, were substantially lower (1.4~11 times) than those found in the typical filter-based samples. This discrepancy is probably due to difficulties in transferring insoluble dust particles to the collection vials in the KSEAS. Temporal profiles of elemental concentrations indicate that some transient events in their concentrations are observed over the sampling periods. For the elemental species studied, atmospheric concentrations during the transient events increased by factors of 4 in Mn~80 in Zn, compared to their background levels. Principle component analyses were applied to the hourly KSEAS data sets to identify sources affecting the concentrations of the metal constituents observed. In this study, we conclude that hourly measurements for particle-bound elemental constituents were extremely useful for revealing the short-term variability in their concentrations and developing insights into their sources.

• International Journal of Naval Architecture and Ocean Engineering
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• 제10권1호
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• pp.1-8
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• 2018

As the key equipment in deep ocean mining, the slurry pump suffers from wear and blocking problems. In this paper, high-speed photography technique is applied to track the movement rule of single particle of the coarse particle solid-liquid two-phase flow in a double blade slurry pump. The influences of particle diameter and particle density on the pass-through and collision characteristics of particles are analyzed as well. The results show that the average of the passing pump time first decreases and then increases when the particle diameter increases. The average of the passing pump time decreases by 22.7%, when the particle density increases from $1.09g/cm^3$ to $1.75g/cm^3$. Besides, the particle density has great influence on the location where the particle hits the tongue. Most particles of $1.09g/cm^3$ hit the tongue on the left side, while collision location of particles of $1.75g/cm^3$ is mainly on the top and at the right side of the tongue. The research can provide a basis for the optimization design of slurry pump in deep ocean mining system.

• 한국초전도ㆍ저온공학회논문지
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• 제19권1호
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• pp.17-21
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• 2017

Vanadium slags is a kind of vanadiferous solid waste from steelmaking process. It not only occupies land, pollutes environment, but also leads to waste of resources. Based on the difference of magnetic susceptibility of different particles caused by their chemical and physical properties from vanadium slag, a new technology, superconducting high gradient magnetic separation was investigated for separation and extraction of valuable substances from vanadium slag. The magnetic concentrate was obtained under optimal parameters, i.e., a particle size -200 mesh, a magnetic flux density of 0.8 T, a slurry concentration of 5 g/L, an amount of steel wools of 25 g and a slurry flow velocity of 2 L/min. The content of $Fe_2O_3$ in concentrate could be increased from 39.6% to 55.0% and $V_2O_5$ from 2.5% to 4.0%, respectively. The recovery rate is up to 42.9%, and the vanadium slag has been effectively reused.

• 한국세라믹학회지
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• 제33권6호
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• pp.700-708
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• 1996

TiO2 membranes for microfiltration were prepared on $\alpha$-alumina support tube by slurry coating. The coating layer was obtained by flowing TiO2 slip on the inner surface of the alumina support. TiO2 membranes were heat-treated at 9$25^{\circ}C$ for 2 hrs. The thickness of the unsupported membrane was about 10${\mu}{\textrm}{m}$. The mean pore diameter of the membranes were 0.09 and 0.15${\mu}{\textrm}{m}$ respectively and the pure water flux was 900~1,200ι/m2.hr at room temperature and 1 bar. For a possible application of oily wastewater treatement an kerosene/wa-ter emulsion was separated in terms of flux and removal efficiency. In 60 min of operating time the flux of TiO2 membranes was 50~100 ι/m2.hr and removal efficiency was over 97% at 3kgf/cm2 of operating pres-sure and 600 ml/min of flow rate. TiO2 membranes could be recycled by reheat treatments at $600^{\circ}C$ for 2 hrs.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.1308-1311
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• 2004

It is very important that get polishing characteristic that to be stable that accomplish planarization of high efficiency in chemical mechanical polishing, and there is repeatability Groove of pad causes much effects in flow of slurry among various factors that influence in polishing characteristic, is expected to cause change of lubrication state and polishing characteristic in contact between wafer and pad. Therefore, divided factors of pad groove by groove pattern, groove profile, groove dimensions. This research wishes to study effect that dimension of pad groove gets in polishing performance. When changed dimension (width, depth, pitch of groove) of groove, measured change of removal rate and friction force. According as groove dimension changes, could confirm that removal rate and friction force change. While result of this experiment studies effect of pad groove in CMP, it is expected to become small help.

• 한국전기전자재료학회논문지
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• 제21권3호
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• pp.203-207
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• 2008

Chemical mechanical polishing (CMP) allows the planarization of wafers with two or more materials. There are many elements such as slurry, polishing pad, process parameters and conditioning in CMP process. Especially, polishing pad is considered as one of the most important consumables because this affects its performances such as WIWNU(within wafer non-uniformity) and MRR(material removal rate). In polishing pad, grooves and pores on its surface affect distribution of slurry, flow and profile of MRR on wafer. A subject of this investigation is to apply CMP for planarization of shallow trench isolation structure using microstructure(MS) pad. MS pad is designed to have uniform structure on its surface and manufactured by micro-molding technology. And then STI CMP performances such as pattern selectivity, erosion and comer rounding are evaluated.