• Journal of Navigation and Port Research
• /
• v.38 no.3
• /
• pp.239-246
• /
• 2014

A study on the elution characteristics of biostimulating agents (sulfate and nitrate) from biostimulants which are used for in-situ bioremediation for the coastal sediment contaminated with organic matter was performed. The biostimulating agents were mixed with the coastal sediment, and then massed the mixture into ball. Two kinds of ball type biostimulant were prepared by coating the ball surface with two different polymers, cellulose acetate and polysulfone. A granular type biostimulant (GTB) was also prepared by impregnating a granular activated carbon in the biostimulating agent solution. The image of scanning electron microscopy for the biostimulant coated with cellulose acetate (CAB) showed that the inner side of the coating layer consisted of irregular and bigger size of pores, and the surface layer had tight structure like beehive. For the biostimulant coated with polyfulfone (PSB), the whole coating layer had a fine structure without pore. The elution rate of the biostimulating agents for the CAB was higher than that for the PSB, and the elution rate for the GTB was considerably higher than that for the PSB in distilled water as well as in sea water. The elution rate of the biostimulating agents in turbulent water flow was about 3 times higher than that in standing water, and the elution rate of nitrate was higher than that of sulfate from the stimulating agents.

• Korean Journal of Materials Research
• /
• v.9 no.8
• /
• pp.804-809
• /
• 1999

Silica films were prepared on Si single crystal substrates by a sol-gel process without DMF using TEOS as a starting material. Films were fabricated by spin coating technique. For films having a composition of TEOS : HCI(1:0.05mol), gelation time, the thickness of films, the formation of cracks and the microstructure of the films were investigated as a function of the molar ratio of $CH_3OH and H_2O$. With 8mol $CH_3OH$, the longest gelation time was measured to be 640hr. The thickness of the coated films was decreased with increasing content of $CH_3OH$. The films were sintered at $500^{\circ}C$ for 1hr with a heating rate of $0.6^{\circ}C$/min. The coated films showed worm-like grains and partially cracked microstructures at an amount of $CH_3OH$ 2mol and 4mol. The addition of more than 8 mole of $CH_2OH$ resulted in crack-free silica films. This suggests that crack-free films can be fabricated by controlling the surface tension energy of the sol solutions without DMF.

• Korean Chemical Engineering Research
• /
• v.43 no.6
• /
• pp.675-682
• /
• 2005

Al containing mesoporous molecular sieve (Al-MMS) was synthesized by hydrolysis of $H_2SiF_6$ and $Al(NO_3)_3{\cdot}9H_2O$. The material obtained was characterized by XRD, $N_2$-physisorption. The specific surface area was $981m^2/g$, and the average pore size was uniformity $39{\AA}$. It was confirmed that the acidity of Al-MMS was milder than that of zeolite Y based on the results of $NH_3$-TPD. Active materials, Pt and Pd, were loaded on Al-MMS in order to examine the feasibility of using Al-MMS as a catalyst support in the hydrogenation of aromatic compounds included in the residue oil of a naphtha cracker. The hydrogenation activity of PtPd/Al-MMS has been studied by following the kinetics of the hydrogenation of naphthalene, and by comparing the kinetic parameters obtained with Pt and Pd catalysts supported on the other mesoporous material support and commercial conventional support materials. PtPd/Al-MMS catalyst shows the highest activity of hydrogenation and sulfur resistance. The high activity of PtPd/Al-MMS was confirmed again in the hydrogenation of PGO (pyrolized gas oil), which is residue oil obtained from a naphtha cracker. Therefore, PtPd/Al-MMS can be applied to the hydrogenation of aromatic compounds included in the residue oil of a commercial naphtha cracker commericially.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2017.05a
• /
• pp.83-83
• /
• 2017

생체재료의 표면은 이식과 동시에 생체계면의 역할을 하게 되어, 일련의 생물학적 반응이 시작되고 진행되는 중요한 장소가 된다. 초기에 생체계면에서 일어나는 단백질 흡착이나 염증반응을 비롯한 생물학적 반응들은 궁극적으로 임플란트의 성패를 좌우할 만큼 중요하다. 골융합을 개선하기 위한 다른 방법으로 생체불활성의 타이타늄 (Ti)과 골조직의 능동적인 반응을 이루기 위해 생체활성 표면을 부여함으로서 계면에서의 골형성 반응을 증진시키는 방법이 이용된다. 생체불활성의 Ti과 Ti합금은 골조직과 직접적인 결합을 이루지 못하므로, 골조직과의 반응을 향상하기 위해 여러 종류의 생체활성 재료를 코팅하는 방법이 연구되어 왔고, 이 중 생체의 변화와 가장 유사한 하이드록시아파타이트 코팅이 가장 대중적인 방법으로 사용되었으며 이는 초기 골형성을 촉진하는 것으로 알려졌다. 치과용 임플란트의 표면형상과 화학조성이 골 융합에 영향을 미치는 가장 중요한 인자이므로 최근의 연구동향은 이들 두 가지 표면특성을 결합함으로서 결과적으로 최적의 골세포반응을 유도하고, 골융합 후 골조직과의 micromechanical interlocking에 의해 임플란트의 안정성에 중요한 역할을 하는 마이크론 단위의 표면조도와 표면 구조를 유지하면서, 부가적으로 골 조직 반응을 능동적으로 개선할 수 있는 생체활성 성분을 부여하여 골 융합에 상승효과를 이루기 위한 표면처리법에 관해 많은 연구가 요구되어지고 있다. 따라서 골을 구하는 원소인 망간과 실리콘으로 치환된 하이드록시아파타이트를 플라즈마 전해 산화법으로 코팅하여 세포와 잘 결합할 수 있는 표면을 제공함으로써 골 융합과 치유기간을 단축시킬 수 있을 것으로 사료된다. 실험방법은 시편은 치과 임플란트 제작 합금인 Ti-6Al-4V ELI disk (grade 5, Timet Co., USA; diameter, 10 mm, thickness, 3 mm)이며, calcium acetate monohydrate, calcium glycerophosphate, manganese(II) acetate tetrahydrate, sodium metasilicate을 설계조건에 따라 혼합 제조된 전해질 용액을 이용하여 플라즈마 전해 산화법으로 표면 코팅을 실시하였다. 각 시편의 플라즈마 전해시 전압은 280V로 인가하였고, 전류밀도는 70mA로 정전류를 공급하여 해당 인가전압 도달 후 3분 동안 정전압 방식을 유지하였다. 코팅된 피막 표면을 주사전자현미경과 X-선 회절분석을 통하여 미세구조 및 결정상을 관찰하였다. 또한 코팅된 표면의 생체활성 평가는 정량적으로 평가하기 위해 동전위시험과 AC 임피던스를 통하여 시행하였다. 분극거동을 확인하기 위해 potentiostat (Model PARSTAT 2273, EG&G, USA)을 이용하여 구강 내 환경과 유사한 $36.5{\pm}1^{\circ}C$의 0.9 wt.% NaCl에서 실시하였다. 전기화학적 부식 거동은 potentiodynamic 방법으로 조사하였고 인가전위는 -1500 mV에서 2000 mV까지 분당 1.67 mV/min 의 주사속도로 인가하여 시험을 수행하였다. 임피던스 측정은 potentiostat (Model PARSTAT 2273, EG&G, USA)을 이용하였으며, 측정에 사용한 주파수 영역은 10mHz ~ 100kHz 까지의 범위로 하여 조사하였고 ZSimWin(Princeton applied Research, USA) 소프트웨어를 사용하여 용액의 저항, 분극 저항 값을 산출하였다. 망간의 함량이 증가할수록 불규칙한 기공을 보였으며, 실리콘은 $TiO_2$ 산화막 형성을 저해하는 경향을 확인할 수 있었다. 단독으로 표면을 처리한 경우보다 두 가지 원소를 이용해 복합 표면처리를 시행한 경우가 내식성이 좋아 임플란트과의 골 유착에 긍정적인 영향을 미칠 것으로 사료된다.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.36 no.6
• /
• pp.807-812
• /
• 2007

In order to enhance the flavor and storage stability of meat sauce, the manufacturing process of fermented beef-rib sauce was developed in a two-step process. The fermented sauce base was manufactured with Zygosaccharomyces rouxii Y-80 yeast cultivation in raw sauce ingredients for 3 days at $25^{\circ}C$. The fermented beef-rib sauce (FBS) was produced by mixing fermented sauce base with side ingredients. Comparison of the physicochemical and sensory properties with non-fermented beef-rib sauce (NFBS) revealed that the content of ethanol and volatile flavor compounds were higher in FBS; also, the result of sensory evaluation showed that FBS obtained excellent scores for overall taste. To determine the storage stability, FBS and NFBS were incubated at $25^{\circ}C$ for 7 days. The extent of decrease of pH and increase of titratable acidity in NFBS were faster than FBS. After 7 days, ethanol concentrations in FBS and NFBS were 3.77% and 2.04%, respectively. Therefore, based on these results, it can be suggested that storage stability of FBS is superior.

• Journal of the Korean Electrochemical Society
• /
• v.6 no.4
• /
• pp.242-249
• /
• 2003

Zn electrode was widely used as an anode material in alkaline battery systems in highly concentrated KOH electrolyte, however it was well known that its cycle life is significantly shortened by growth of dendrite due to the high dissolution of $Zn(OH)_2$ and rapid electrochemical reaction. In this study when by the additives such as $Ca(OH)_2$, Citrate, tartrate and Gluconate were added to $40\%$ KOH electrolyte at solution temperature of $25^{\circ}C$ and the amount of $5wt\%\;Pb_3O_4$ was mixed to Zn electrode and then the effect of $Pb_3O_4$ and additives on the electrochemical behavior of Zn electrode was investigated by Potentiodynamic Polarization Curves, Cyclic Voltammetry, Accelerated Life Cycle lest, and SEM image analyses. The addition of $Pb_3O_4$ reduced the corrosion rate of Zn electrode. The corrosion potential of Zn electrode with $Pb_3O_4$ was higher or lower than that of pure Zn electrode however was not influenced practically to the open circuit voltage. And the addition of 4 type additives had an important role in improving both cycle life in accelerated cycle life test and corrosion resistance. Furthermore the additive of Tartrate indicated comparatively a good effect to corrosion resistance as well as charging-discharging property Improvement among those four type additives.

• Journal of Korean Society of Environmental Engineers
• /
• v.33 no.5
• /
• pp.368-377
• /
• 2011

A package type of SCR (selective catalytic reduction) system that was proposed for removing the $NO_x$ found in flue gas from the small scale of air pollution sources was evaluated. The efficiency of the SCR system is determined by the proper utilization of catalytic media installed inside of the system, and the proper distribution of flow velocity and $NH_3$ concentration in the flue gas is a crucial factor for using the catalytic media. In this study, the distributions of $NH_3$ concentration were estimated under the various arrays and shapes of AIG at the given gas flow condition. The value of RMS (%) in $NH_3$ concentration is 95.3% at co-current flow (at $0^{\circ}$) injection but it is 90.1% at the condition of counter-current flow (at $120^{\circ}$) condition, which implies the counter-current injection is more favorable. By rearranging the $NH_3$ injection flow rates based on the distribution of velocity and $NH_3$ distribution in basic calculation, the value of RMS (%) in $NH_3$ concentration was reduced to 62.8%. The enhanced effect of $NH_3$ mixing by the combined effect of arrays and shapes are complied in the study.

• Journal of Korean Society of Environmental Engineers
• /
• v.37 no.12
• /
• pp.668-673
• /
• 2015

Alumina-based catalysts with different Ce loadings were studied in the decomposition of $CF_4$ using microwave heating system. Heating material of microwave system used Silicon Carbide. The crystallographic phases of catalysts were investigated by XRD and decomposition rates of $CF_4$ were examined by GC-TCD. The catalysts of 10 wt% Ce modified $Al_2O_3$ showed higher $CF_4$ decomposition rate than un-modified $Al_2O_3$ for $500^{\circ}C$ reaction temperature. The k value of catalysts shows the order of $Ce(20)/Al_2O_3=Ce(0)/Al_2O_3<Ce(5)/Al_2O_3<Ce(10)/Al_2O_3$. XRD patterns of $Ce(0)/Al_2O_3$ were no difference before and after the reaction and showed $Al_2O_3$ phases. With the increase in Ce loadings, $CeO_2$, $AlF_3$ of XRD peaks was observed. The results was indicated that Ce modifed $Al_2O_3$ than un-modifed $Al_2O_3$ was decreased reaction temperature to $200^{\circ}C$ with same decomposition rate. Also the appropriated cerium sulfate loadings on $Al_2O_3$ were 5~10 wt%.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2006.04a
• /
• pp.166-170
• /
• 2006

본 연구에서는 폐광산 주변에 산재되어 있는 광미/광폐석을 처리하기 위하여 고형화 실증 실험을 수행하였다. 고형화 공정에서 흔히 사용하는 포틀랜드 시멘트와 MSG-E, MSG-N을 고화제로 사용하였으며 현장 광미 및 광폐석을 대상으로 고화체를 양생하고 고화체의 압축강도 및 중금속 용출 정도를 측정하였다. 고화체의 물리/화학적 특성을 비교하기 위해 광미/고화제 비율, 배합수/고화제 비율 그리고 고화체 양생기간을 실험인자로 설정하였다. 실험 결과 광미/고화제의 비율 1:1 만을 고려하더라도 중금속 용출의 급격한 감소가 이루어지는 것을 확인할 수 있었으며 광미/고화제의 비율을 3:1 이하로 유지시키는 경우, 고화체의 압축강도가 현행 폐기물 관리법(20조 관련)에서 규정하고 있는 차단형 매립시설 내부막의 압축강도 기준인 $0.21kgf/mm^2$ 보다 높은 것으로 나타났다. 다양한 pH를 갖는 수용액에 대하여 시간에 따른 고화체의 중금속 용출률을 측정한 결과, 수용액의 pH가 1과 13인 강산/강염기 용액에서 일부 중금속의 용출 농도가 지하수 생활용수 기준치를 초과하였으나, pH와 3 - 11인 경우에는 중금속 용출률이 급격히 감소하여 모두 기준치 이하를 나타내었다. 또한, pH가 1과 13인 수용액의 경우에도 고화체와 반응하는 시간이 증가할수록 고화체의 buffering 효과에 의해 수용액의 pH가 감소하였다. 이러한 결과는 현장에서 접촉수의 pH가 강산이나 강염기라 하여도, 고화체의 buffering 효과에 의해 시간이 지남에 따라 수용액의 pH가 낮아져 고화체로부터의 중금속 용출은 매우 감소할 것임을 의미한다.ss of an active application defined using the model. The technique is developed in a platform- and language-independent way, and it is algorithmic and can be automated by computer program. We give an example dealing with network auction to illustrate the use of the model and the verification technique.품으로 내부 온도분포를 측정하였으며, 유한차분법 프로그램으로 대류열전달계수를 결정하였다. 대류열전달계수는 792에서 2,107 W/m$^2$로 분석되었다. 대류열전달 계수는 액상식품과의 상대속도가 증가함에 따라서 증가하였고, 점도가 증가함에 따라서는 감소하였다.ce of precision/recall of 90.99%/92.52%, and 93.39%/93.41% respectively. 의한 변성에 부분적으로 보호 작용을 나타 낼 것으로 추정된다.경(製麴72時間頃)의 활성(活性)은 보리쌀국(麴), 밀가루국(麴), 찹쌀국(麴), 고구마국(麴)의 순이었다.험 결과 오전용 사료는 관행적인 산란계 배합사료에서 Ca공급제를 제외한 것을 급여하고, 오후용 사료는 Ca공급제를 3배 첨가한 T2처리로 15:00~16:00시에 교체급여를 하면 사료섭취량 감소와 사료비 절감면에서 바람직할 것으로 사료되며, 고에너지-고단백질-저Ca의 분말사료와 저에너지-저단백질-고Ca의 펠렛사료를 혼합급여하면 산란계의 사료

• Journal of the Korean Wood Science and Technology
• /
• v.27 no.1
• /
• pp.30-36
• /
• 1999

This paper describes the relationship between the bending strength properties of sloped finger-jointed woods and the acoustic emissions (AEs) generated during the test. Pinus densiflora pieces were cut in sloped-finger types and glued with four kinds of adhesives (polyvinyl acetate, polyvinyl-aeryl, oilic urethane and resorcinol-phenol resin). The results were as follows: The lower the bending strength(load) was, the earlier the generation time of AE event count got and the higher the increasing rate of AE event count became in the sloped finger-jointed specimens bonded with polyvinyl acetate and oilic urethane resin adhesives. Therefore, the slope from load-AE cumulative event count curve was very steep. The AE event count for resorcinol-phenol resin adhesive obtained even from low load level was abundant. The AE event count continuously increased as load increased and the event count was much more than one in the other conditions. The slope from load-AE cumulative event count curve was very gentle compared with other conditions. The patterns of AE event count and count were very similar. The relationship between the MOR and the AE parameter from load and AE cumulative event count in the early stage of the sloped finger-jointed specimens bonded with polyvinyl acetate, oilic urethane and resorcinol-phenol resin adhesives was much greater than that between the MOE and the MOR. Therefore, the AE signals obtained during bending test are useful for estimating the strength of sloped finger-jointed specimens.