• Food Engineering Progress
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• v.23 no.4
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• pp.283-289
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• 2019

This study was performed to determine the effect of psyllium husk addition on the physical properties of rice extrudates. Rice-based formulations mixed with psyllium husk (0, 7, 14 and 21%) were extruded at a die temperature of 140℃, screw speed of 200 rpm, and moisture content of 20%. As the content of psyllium husk increased, expansion ratio decreased, while piece density and specific length increased. Apparent elastic modulus, breaking strength, adhesiveness, and hardness augmented with an elevation in psyllium husk content. Lightness declined as psyllium husk content furthered, while redness, yellowness, and color difference intensified. Water soluble index and water absorption index increased with an increased amount of psyllium husk. In conclusion, the addition of psyllium affected the expansion of extruded rice snack possessing hard texture, small cells, and sticky texture due to higher water absorption during hydration.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.100.1-100.1
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• 2015

중이온가속기에서 잔류기체 분자와 가속 이온의 충돌이 발생하면 이온빔 전류의 손실을 야기하는 직접적인 효과 외에 잔류 기체분자 중에서 전리된 이온들이 반발력에 의해 용기 벽에 부딪힐 때 표면에 흡착되어 있던 기체분자들을 충격탈리(stimulated desorption)시킨다. 더 심각한 경우는 산란된 고속 이온이 용기 벽과 충돌하면서 핵반응을 일으켜 방사화 시키거나 벽에서 다량의 기체를 방출시키는 것이다. 최악의 경우에는 고속이온의 에너지에 의해 용기벽이나 부품들이 열적인 손상을 입을 수도 있다. 현재 설계 및 연구개발이 진행중인 기초과학원(IBS) RISP (Rare Isotope Science Project)의 RAON 중이온가속기는 입사기에서 실험영역까지 각 부분의 진공도 조건이 일반적으로 10-8~10-9 mbar 대에 있어서 이온빔 전류의 손실이나 전리 이온들에 의한 충격탈리는 무시할 수도 있지만 고속이온의 기체방출 수율이 ~104 정도로 높은 것을 감안할 때 고속이온의 충격탈리에 의한 압력 증가가 감내할 수준인지 검토할 필요가 있다. 압력증가는 추가적인 손실을 유발하고 이것은 다시 압력을 상승시키는 진공 불안정성(vacuum instability)을 야기할 수 있다는 축면에서 조심하는 것이 좋다고 판단된다. 고속 중이온과 잔류기체 분자와의 충돌에서 이온이 손실되는 반응에는 쿨롬(coulomb) 산란과 전하교환(charge exchange)이 있는데 전자는 후자에 비해 일반적으로 1/10000 가까이 낮아서 무시할 수 있고, 전자 포획(electron capture) 또는 전자 손실(electron loss, 이온의 전리에 해당)로 대별되는 전하교환 반응이 이온 손실을 주도하는 것으로 알려져 있다. 이 연구에서는 다양한 전하교환 반응 단면적을 아우르는 비례칙(scaling law)을 사용하여 대표적인 중이온인 U33+ 및 U79+의 손실 및 잔류 기체의 전리율을 계산하고 충격탈리에 의한 표면방출 및 압력상승을 일차적으로 고려하여 진공도 조건의 타당성을 입증하려고 한다.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.3
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• pp.41-46
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• 2008

Etching kinetics of $EAGLE^{2000TM}$ LCD glass was investigated using 2.5MHF-xMHCl$(x:0\sim8)$ acid mixtures. It was concluded that the reaction of HF-containing solutions with the glass was the rate-determining step for the dissolution process when considering following observations; the value of the activation energy $35\sim45$ kJ/mol and insensitivity of the dissolution rate to the etching time and the moving velocity of the glass into the solution. The etching rate linearly increased with increasing the HCl concentration in the etchant. It was also observed that the etched surface was as smooth as the original surface by addition of HCl and increase in etching temperature. This is due to the catalytic role of the $H_{3}O^{+]$ ions in the dissolution process.

• Journal of environmental and Sanitary engineering
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• v.15 no.3
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• pp.88-93
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• 2000

The objective of this study was to depict the kinetic behavior of the platinum catalyst for the deep oxidation of VOCs and their mixture. The oxidation characteristics of VOCs, which were benzene, toluene, and styrene, was studies on a 0.5% $Pt/{\gamma}-Al_2O_3$ catalyst. The reactivity increases in order benzene>toluene>styrene. In mixtures, remarkable effects on reaction rate and selectivity have been evident ; the strongest inhibiting effect was shown by styrene and increases in a reverse order with respect to that of reactivity. The reaction model reveals that there is a competition between the two reactants for the oxidized catalyst. Thus, the nontoxic catalytic oxidation process was suggested as the new VOCs control technology.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.1
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• pp.52-56
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• 1991

In 1986, at Cheju and Seoguipo, a sweet com hybrid, Golden Cross Bantam 70, was grown at 5 phosphate rates (0, 8, 16, 24 and 32 kg/l0a) to determine effects of phosphate rate on growth and yield of sweet com and to recommend the optimum phosphate rate for sweet com production in volcanic ash soils of Cheju province. Days to silking were shortened 1 to 2 days by phosphate application of more than l6kg/10a. Culm length, ear height and fresh stover yield/l0a did not differ between two locations, but linearly increased as phosphate rate was increased from 0 to 32kg/10a. Average length and weight of marketable ears were greater at Cheju than at Seoguipo and linearly increased as phosphate rate increased. The number of marketable ears per plant and per l0a did not differ between two locations, but quadratically increased as phosphate rate increased. The economic optimum phosphate rate estimated on the basis of the quadratic model, ranged 25.6 to 27.4kg/10a at various fertilizer-to-ear price ratios.

• Microbiology and Biotechnology Letters
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• v.14 no.6
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• pp.433-439
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• 1986

Abundant amount of Chiamydia trachomatis could be amplified in mammalian McCoy cells and purified using descontinuous Uroarafin gradient centrifugation. As a chemical means io increase the Chlamydia trachomatis inclusions in McCoy cells IUdR treatment was found to be more effective than the cycloheximide treatment and was recommendanble for the proliferation of Chlamydia trachomatis. Centrifugation promoted Chlamydia trachomatis adhesion to McCoy cell surface, and maximal percentage of infected cells was obtained at about 3000g. The purified Chlamydia trachomatis could be kept in SPG solution for 48 hours at +4$^{\circ}C$ but for longer storage freezing to -7$0^{\circ}C$ was necessary.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.4
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• pp.295-302
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• 2002

PAHs (polycyclic aromatic hydrocarbons) deposited in soil are one of serious problems against sustainable land use. In this paper, chemical soil flushing in a packed sandy soil matrix using a natural surfactant, $\beta$-cyclodextrin (CD) was studied via a fluorescence spectroscopy and a dye labelling. The contaminants are lipophilic ring compounds- phenanthrene and naphthalene. Sand type and flushing intensity (rate and concentration) are chosen as important investigation variables. The removal efficiencies were proportional to flow rate, concentration, temperature of the flushing solution and voidity of the sand column. Initial sorption of the surfactant onto the soil matrix was found to be a key step while flow shear was more crucial in the latter steps. The residual portion of the surfactant, which was most likely to be due to the initial sorption, would not be so influential on this type of soil washing for long times. These results will be useful in future for pilot scale in situ washing and for establishing better soil washing strategy.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.145-152
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• 1996

A fine oil-in-water (O/W) emulsion using nonaqueous emulsification technique was developed and the behaviors of POE(25)octyldodecyl ether in nonaqueous solvent/oil systems were studied by observing the surface tension, interfacial tension, turbidity and transition temperature. It was found that POE(25)octyldodecyl ether existed soluble in nonaqueous solvent while, in aqueous system, it formed micelles. So, when a solvent, like glycerine in which POE(25)octyldodecyl ether has poor solubility, was added, POE(25)octyldodecyl ether moved to the surface. After saturated at surface, POE(25) octyldodecyl ether began to precitate. The mean particle size of the final emulsion was 230nm. Also, the emulsion system was stable at 0, 25, 40, $50^{\circ}C$ and cycling test for a month, while the conventional emulsion system showed unstability. It is concluded that, by pertinent combination of solvents, the adsorption efficiency of surfactant could be improved.

• KSBB Journal
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• v.18 no.5
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• pp.371-376
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• 2003

Antioxidative and cholesterol-reducing activity of Bacillus polyfermenticus SCD were measured to characterize its probiotic properties. DPPH (1,1-diphenyl-2-picyryl hydrazyl) radical scavenging activity of the culture supernatant of B. polyfermenticus SCD was estimated to be 48%. The culture supernatant on the peroxidation of linoleic acid were investigated and the value was shown to be about 45%. The inhibition of TBA (2-thiobarbituric acid) formation of the culture supernatant was revealed 60% when stimulator was presented. The SOD-like activity of the culture supernatant was about 15%, which is similar to BHT (butylated hydroxytoluene) and ${\alpha}$-tocopherol. After cultured in TSB broth added soluble cholesterol either 0.1% or 0.3% of oxgall in 37$^{\circ}C$ for 24 h aerobically, cholesterol-reducing activities were revealed about 67% or 64%, respectively. To test whether the products are cholesterol-related or not, residual activity was determined. The cholesterol activity was rarely changed. In addition, when the cell extracts recovered after cultivation, was tested in absence of cholesterol, cholesterol activity was not detected. However, cholesterol activity was detected in the presence of cholesterol. Thus, it was assumed that B. polyfermenticus SCD could reduce cholesterol by conjugating with it, rather than by digesting the cholesterol using cholesterol-hydrolyzing enzymes.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.2003-2005
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• 2002

바이오 마이크로 시스템 및 바이오 MEMS 분야, 특히 실리콘을 기질로 하는 바이오 센서 제작에서 반도체 공정 기술은 센서의 대량 생산과 초소형화를 위해서 반드시 필요한 기술이다. 그러나, 감지전극의 마이크로화에 따른 센서의 감도 및 안정성 저하 문제는 해결해야 할 과제이다. 최근, 다공질 실리콘이 갖는 대면적이 실리콘 기질과 생체 고분자 (예: 단백질, 핵산 등) 간의 결합력을 향상시킬 수 있음이 알려지면서, 바이오 센서 분야에서, 새로운 형태의 드랜스듀서 재료로서의 다공질 실리콘에 대한 논의가 활발히 전개되고 있으며 또한, ISFET (Ion-Selective Field-Effect Transistors) 와는 달리 다공질 실리콘 층은 저항이 크기 때문에 센서 제작 과정에서의 부가적인 절연막을 필요로 하지 않는다. 본 연구에서는, 백금을 증착한 다공질 실리콘 표면에 전도성 고분자로서 Polypyrrole (PPy) 필름과 생체 고분자 물질로서 Urease를 각각 전기화학적으로 흡착하였다. 다공질 실리콘 층의 형성을 위해 테플론 소재의 전기화학 전지에 불산 (49%), 에탄올 (95%), $H_2O$ 혼합 용액을 넣고 실리콘 웨이퍼에 일정시간 수 mA의 산화 전류를 흘려주었으며, 약 $200{\AA}$의 티타늄 박막과 $200{\AA}$의 백금 박막을 RF 스퍼터링하여 작업 전극을 제작하였고, 백금 박막 및 Ag를 기화 증착하여 제작한 Ag/AgCl 박막을 각각 상대 전극과 기준전극으로 하였다. 박막 전극의 표면 분석을 위해 SEM (Scanning Electron Microscopy), EDX (Energy Dispersive X-ray spectroscopy) 등을 이용하였다. 제작된 요소 센서로부터 요소 농도 범위 0.01 mmol/L ${\sim}$ 100 mmol/L에서 약 0.2 mA/decade의 감도를 얻었다.