• 공업화학
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• 제16권3호
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• pp.427-433
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• 2005

마이크로파를 이용한 인삼으로부터 가용성 성분을 추출할 때의 용매(에탄올-물) 사용량, 고체 입자크기, 마이크로파 전력의 영향과 용매-인삼 혼합물의 마이크로파 가열 특성 및 팽윤도에 대하여 검토하였다. 용매와 인삼의 비는 6 : 1(vol. of solvent to mass of ginseng)이 적당하였고 인삼 입자는 작을수록 추출률이 높았으나 슬러리를 여과하여 여분의 용매를 분리하기가 매우 곤란하였다. 마이크로파 전력은 세기가 클수록 추출 속도는 빨라지나 추출률은 투입되는 전체 에너지양에 영향 받는 것을 확인할 수 있었다. 마이크로파와 물중탕으로 가열한 인삼의 수분 흡수량으로부터 구한 질량기준 팽윤도는 마이크로파로 가열하였을 때 더 빠르게 일어났으며 이러한 결과가 마이크로파를 이용한 추출이 종래의 추출방법에 비하여 추출률이 높고 속도가 빨라지게 되는 요인일 것으로 판단되었다.

• Journal of Pharmaceutical Investigation
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• 제18권3호
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• pp.113-123
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• 1988

A series of water-soluble polyparacyclophanes bearing two diphenylmethane or two diphenyl ether skeletons were investigated to develop useful host compounds by using 1-anilinonaphthalene-6-sulfonate (ANS) and 2-p-toluidinylnaphthalene-6-sulfonate (TNS) as fluorescent hydrophobic substrates in aqueous solution. It was noteworthy that remarkable fluorescent enhancements and blue shifts of ANS and TNS were observed only in the presence of 1,6,20,25-tetraaza[6.1.6.1] paracyclophane (CPM 44) and 1,6,21,27-tetraaza [7.1.7.1] paracyclophane (CPM 55) for diphenylmethane skeleton, and 1,7,21,27-tetraaza-14,34-dioxa [7.1.7.1] paracyclophane (CPE 55) and 1,8,22,29-tetraaza-15,36-dioxa [8.1.8.1] paracyclophane (CPE 66) for diphenyl ether skeleton, comparing with ${\alpha}-\;and\;{\beta}-cyclodextrins$. However, their acyclic analogues such as 4,4'-dimethylaminodiphenylmethane and 4,4'-dimethylaminodiphenyl ether, and paracyclophanes whose cavities were smaller showed only small effects under the same conditions. These facts suggested that hosts and substrates were in an intimate contact which would not occur without larger structures, and thus that guest molecules were strongly incorporated in the hydrophobic cavities of these larger paracyclophanes. The effects of pH on the fluorescent intensity of ANS-CPM 44, ANS-CPM 55, ANS-CPE 55, ANS-CPE 66, TNS-CPM 44, TNS-CPM 55, TNS-CPE 55 and TNS-CPE 66 systems were not significant below pH 2.0, but their fluorescent intensities were markedly reduced with increasing ionic strength.

• 한국농공학회논문집
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• 제54권1호
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• pp.63-72
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• 2012

In livestock industry, damage caused by the epidemic diseases such as Foot-and-Mouth Disease (FMD), Highly-Pathogenic-Avian-Influenza (HPAI) and Porcine-Reproductive-and-Respiratory-Syndrome (PRRS) was very serious. The financial loss incurred from FMD alone which occurred on Nov. 2011 in Korea was estimated at 3 billion won, 23 % of annual livestock industry production. The livestock industry in Korea has greater risk of disease infection because of high density production, etc. Investigating the spread of livestock diseases should consider both direct and indirect contact as well as other various factors including airborne. Airborne infection of livestock disease was first hypothesised in the early 1900s, however, field experimental studies are still limited. Furthermore, no protocol is available in detecting airborne viruses in the field. In this study, effective virus samplers were investigated by comparative analysis of the type of samplers used detect to airborne virus. Laboratory experiments were conducted to compare virus samplers such as Bio-sampler, Dust-sampler, Compact-Cascade-Impactor (CCI) and Microflow in detecting PRRSV. Samples were analyzed by Reverse-Transcription PCR to assess the efficiency of the instrument in detecting the airborne virus. First, samples were classified into five levels according to light intensity of gel images and then the classified results were normalized. In every case, Bio-sampler and Dust-sampler were comparable with each other and have shown to be more effective than CCI and Microflow samplers.

• Environmental Engineering Research
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• 제21권2호
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• pp.121-131
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• 2016

In most African urban areas, Particulate Matters (PM) concentration exceeds by far the WHO limits. In these areas, plants can play a key role in removing particles. In this study, we evaluated three ornamental species (Jatropha interrigima, Ficus benjamina, Barleria prionitis) used in Abidjan (Ivory Coast). Leaf-encapsulated saturation isothermal remnant magnetisation (SIRM) were measured and the relationship between PM captured and leaf wettability were done. The sampling were performed at roadsides and Parks. Firstly, Leaf-encapsulated and total leaf SIRM were quantified and the wettability was determined by drop contact angles (DCA). Secondly, the relationship between leaf SIRM and wettability was found. Results showed that leaf SIRM was two to ten times higher at roadsides than in Parks. Total leaf SIRM was also higher on mature leaves in Main roads suggesting a particle accumulation in leaves over time especially in waxy species (Ficus benjamina). This species encapsulated other than 20% of total leaf SIRM. All tested species were highly-wettable ($40^{\circ}$ < DCA < $90^{\circ}$). Thus, Jatropha interrigima with its leaf trichomes and F. benjamina with its leaf waxes were more wettable. A significantly positive correlation was found between wettability intensity and leaf SIRM.

• 폴리머
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• 제25권3호
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• pp.435-440
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• 2001

본 연구에서는 일방향 탄소/탄소 복합재료에 산화억제제로 사용된 $MoSi_2$의 첨가량에 따른 복합재료의 부착력, 파괴인성 그리고 충격강도와의 관계를 고찰하였다. 산화억제제로 사용한 이규화 몰리브덴 (MoSi$_2$)은 복합재료의 내산화 특성을 향상시키기 위하여 각각 4, 12, 20wt%의 중량비로 페놀수지에 함침시켰다. 본 연구에 있어서 복합재료의 부착력은 접촉각 측정에 의한 Wilhelmy 방정식을 사용하여 계산하였다. 파괴인성과 충격강도는 임계 세기인자 측정을 위한 3점 굴곡 시험 방법과 Izod 충격시험에 의해 각각 측정하였다. 그 결과, $MoSi_2$가 첨가된 탄소/탄소 복합재료의 파괴인성과 충격강도는 증가하였다. 특허 l2wt%의 $MoSi_2$가 첨가된 복합재료가 London dispersive 요소($W_A\;^L$)의 증가에 의한 가장 큰 부착력을 나타내었으며, 이는 복합재료의 각 구성요소간의 계면결합력 증가에 따른 결과라 사료된다.

• 한국물환경학회지
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• 제36권2호
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• pp.137-147
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• 2020

A direct contact membrane distillation (DCMD) was applied to treat strong nitrogenous wastewater of anaerobic digestion supernatant (ADS) and human urine (HU). The ammonia transfer was evaluated in terms of specific ammonia transfer (SAT) value, which is the ratio of total ammoniacal nitrogen divided by the amount of water transferred. The acidification resulted in low SAT values and high quality of produced water. The ammonia transfer control in the acidic condition was stronger for HU than ADS due to higher alkalinity (pH 8.8) and ammonia concentration (5700 mg-N/L) of HU. Acidified HU at pH 4 exhibited a SAT value of 1.64 × 10^-5, which was significantly smaller than the SAT value of 3.00 × 10^-3 for the original HU. The low pH enhanced the water flux for ADS, but HU showed a steep decrease in water flux due to enhanced fouling. It was considered that the fouling intensity in acidic conditions depends on the characteristics of the wastewater source. The major foulants on the MD membrane were NaCl, CaCO₃ and CuSO₄ as recognized by the SEM-EDS. Acidified ADS and HU at pH 4 showed relatively high N content of 8.18 % and 28.03 %, respectively, as organic fouling.

• 전기화학회지
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• 제4권1호
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• pp.10-13
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• 2001

광전기화학적 양극 산화법으로 다공질 실리콘 (porous silicon, PS)을 제조할 때 전해질에 음이온성 계면활성제의 한 종류인 Pentadecafluorooctanoic acid (PDFO)를 첨가하여 제조한 PS의 광발광(photoluminescence, PL)의 변화를 조사하였다. 사용한 웨이퍼는 비저항이 $0.4\~0.8{\Omega}{\cdot}cm$인 n-형 단결정 실리콘 (100)이었으며, 일정전위 4V를 600초 동안 걸어주어 다공성 실리콘을 제조하였다. 이 때 나타난 PL의 변화는 첨가한 계면활성제의 농도가 1mM에서 50mM로 증가함에 따라서 PL의 중심파장이 600nm에서 550nm로 단파장 이동함을 보여주었으며, PL의 세기는 감소함을 보여주었다. FT-IR을 사용하여 에칭된 다공성 실리콘 위에 PDFO가 존재함을 알 수 있었고 Goniometer를 사용한 물방울 각도 측정을 통해서 생성된 표면이 소수성임을 알 수 있었다. 이로부터 계면활성제의 소수성 부분인 포화탄화불소 사슬 부분이 표면에 전체적으로 누워있다고 유추하였다.

• Composites Research
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• 제15권6호
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• pp.16-23
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• 2002

본 연구에서는 양극산화 처리에 따른 고강도 PAN계 탄소섬유의 표면 특성 변화가 기계적 계면 물성에 미치는 영향을 조사하였다. 탄소섬유의 표면성질은 산.염기도, SEM, XPS, 그리고 접촉각 측정을 통하여 알아보았으며, 복합재료의 기계적 계면 특성은 ILSS와 $K_{IC}$를 통하여 고찰하였다. 탄소섬유 표면의 산도와 $O_{ls}/C_{IC}$가 증가하였는데, 이는 산소관능기의 발달에 기인하고, 양극산화된 탄소섬유의 표면자유에너지의 증가는 극성요소의 증가에 기인하는 것으로 사료된다. ILSS와 $K_{IC}$ 같은 기계적 계면 성질은 양극산화로 향상되어졌는데, 이러한 결과는 좋은 젖음성이 최종 복합재료의 섬유와 에폭시 수지 매트릭스 사이의 계면결합력을 증가시기는 중요한 역할을 하기 때문으로 사료된다.

• 공업화학
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• 제24권5호
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• pp.476-482
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• 2013

본 연구에서는 탄소섬유 표면에 가해진 전기화학적 산화처리가 탄소섬유강화 극성화된 폴리프로필렌 기지 복합재료의 기계적 계면 물성에 미치는 영향을 알아보기 위해 전류밀도 변수에 따른 섬유표면의 변화를 관찰하였다. 표면처리 전후의 탄소섬유 표면특성은 주사전자현미경과 원자현미경, 적외선분광법, X선광전자분광법과 접촉각으로 분석하였다. 탄소섬유강화복합재의 기계적 계면특성은 임계응력세기인자를 측정하여 평가하였다. 실험 결과 전기화학적 산화처리 후 섬유 표면의 $O_{1s}$ 피크의 증가를 관찰할 수 있었고, 이는 섬유의 표면자유에너지의 증가를 유도하며, 탄소섬유와 폴리프로필렌의 계면 결합력이 증가된 것으로 판단된다. 결론적으로 탄소섬유강화복합재료의 기계적 물성은 탄소섬유와 극성 폴리프로필렌 기지와의 계면 강도조절을 통해 가능할 것으로 판단된다.

• 한국전기전자재료학회논문지
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• 제29권4호
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• pp.237-240
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• 2016

The improvement of irradiation intensity and irradiation uniformity is essential for large area and high power UVA light source application. In this study, large number of chips bonded by micro soldering technique were driven by low current, and current limiting diodes were configured to supply constant current to parallel circuits consisting of large number of series strings. The dimension of light source module circuit board was $350{\times}90mm^2$ and 16,650 numbers of 385 nm flip chip LEDs were used with a configuration of 90 parallel and 185 series strings. The space between LEDs in parallel and series strings were maintained at 1.9 mm and 1.0 mm distance, respectively. The size of the flip chip was $750{\times}750{\mu}m^2$ were used with contact pads of $260{\times}669{\mu}m^2$ size, and SAC (96.5 Sn/3.0 Ag/0.5 Cu) solder was used for flip chip bonding. The fabricated light source module with 7.5 m A supply current showed temperature rise of $66^{\circ}C$, whereas irradiation was measured to be $300mW/cm^2$. Inaddition, 0.23% variation of the constant current in each series string was demonstrated.