• 한국대기환경학회지
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• 제16권6호
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• pp.595-606
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• 2000

In order to compare analytical conditions for measuring PAHs(polycyclic aromatic hydrocarbons) in ambient air, a series of experiment were conducted using three different types of extraction methods that include:(1) accelerated solvent extraction (ASE), (2) soxhlet, and (3) sonification methods. Efficiency and relevant analytixal parameters for each of these methods were examined on five different types of solvents that include:(1) 10% diethyl ether in n-hexane(v/v), (2) dichloromethane, (3)cyclohexane.(4) toluene, and (5) Benzene: ethanol (4:1). Comparison of extraction efficiency for various combinations between methods and solvents was made through an application of both internal and external standard calibration techniques. The extraction efficiency tests, when checked using both internal and external standards, allowed us to derive meaningful comparison among different techniques and among solvents.

• International journal of advanced smart convergence
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• 제4권1호
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• pp.154-161
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• 2015

A novel process has successfully been developed by overcoming major difficulties through the elimination of number of process steps involved in the Classical Transesterification reaction during the preparation of Fatty Acid Methyl/Ethyl Ester (FAME.FAEE) called biodiesel. The Classical process with cost intensive process steps such as the utilization of excess alcohol, needing downstream distillation for the recovery and reutilization of excess alcohol/cosolvent, unrecoverable homogenous catalyst which consumes vast quantity of fresh distilled water during the purification of the product and downstream waste water treatment before its safe disposal to the surface water body. The Novel Process FAME/FAEE is produced from any vegetable oil irrespective of edible or inedible variety using sonication energy. The novelty of the finding is the use of only theoretical quantity of alcohol along with a co-solvent and reduced quantity of homogeneous catalyst. Under this condition neither the homogeneous catalyst goes to the FAME layer nor is the distillation needed. The same ester also has been prepared in high pressure high temperature reactor without using catalyst at sub critical temperature. The quality of prepared biodiesel without involving any purification step meets the ASTM standards. Blended Biodiesel with Common Diesel Fuel (CDF) and FAME is prepared, characterized and used as fuel in the Kirloskar make CI Engines. The evaluation of the engine performance result of pure CDF, B05 biodiesel, B10 biodiesel of all types of biodiesel prepared by using the feedstock of Soybean (Glycine max) and Karanja (Pongamia pinnate) oil along with their mixed oil provides useful information such as brake power, brake thermal efficiency, brake specific fuel consumption, etc, and established it as ideal fuel for unmodified CI engine.

• 콘크리트학회논문집
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• 제26권1호
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• pp.63-70
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• 2014

이 연구에서는 multi-walled CNT 보강 시멘트 복합체의 효과적인 압축강도 향상을 위하여 섬유 분산을 위한 초음파처리 정도, 계면활성제의 사용량, 실리카퓸 치환율 등을 실험변수로 하여, 그 영향을 실험적으로 살펴보았다. 초음파 처리 시간에 따른 CNT 분산성 변화는 광학현미경을 통해 확인하였으며, CNT 시멘트 복합체의 압축강도가 초음파 처리 정도에 따라 향상됨을 확인할 수 있었다. 계면활성제로 사용된 고성능감수제 사용량의 영향은 SP/CNT비가 4~6일 때 강도향상 효과가 가장 좋은 것으로 나타났다. 한편, 실리카퓸 치환율에 따른 압축강도의 변화에서는 실리카퓸을 10 % 치환했을 때 강도에 대한 CNT 보강효과가 가장 큰 것으로 나타났다. CNT 보강 시멘트 복합체의 미세구조 분석도 함께 실시하였는데, XRD와 SEM 분석 결과에서는 CNT 혼입으로 인한 수화생성물 및 미세구조의 변화는 거의 없는 것으로 나타났으며, MIP 분석을 통해서는 공극률 감소와 함께, $10{\mu}m$ 및 100 nm 크기 전후의 공극분포가 줄어드는 대신 수 십 나노미터 크기의 작은 공극들의 분포가 증가함을 확인하였다. 이를 통해 CNT의 혼입에 따른 압축강도 증가는 화학적 영향보다는 물리적 영향이 큰 것으로 판단된다.

• 상하수도학회지
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• 제14권1호
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• pp.117-126
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• 2000

Solubilization pretreatments were conducted to enhance the anaerobic digestion of the waste activated sludge. Four pretreatment techniques including heating, sonication freezing and thawing, and enzyme addition were employed to solubilize the waste activated sludge under various conditions. Thermal pretreatment by heating showed the highest efficiency compared with other methods, and freezing and thawing was confirmed as a feasible alternative of solubilization as well as the pretreatment of dewatering. There is a clear correlation between the solubilization efficiency of the waste activated sludge and the gas production. Batch digestion results showed the cumulative gas production as much as four times after thermal pretreatment as compared with that by the control sludge without pretreatment. As a result, hydrolysis or solubilization pretreatment might play a significant role in the high rate digestion of the waste activated sludge.

• 한국응용곤충학회지
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• 제54권2호
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• pp.91-97
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• 2015

담배가루이(Bemisia tabaci)는 외래해충으로 바이러스벡터로 작용하여, 토마토의 토마토황하잎말림병바이러스(TYLCV)를 비롯한 약 100여종의 바이러스를 매개하는 중요한 해충이다. 본 연구에서는 VIGS vector를 이용하여 담배가루이 방제를 위한 target 유전자들을 선발하기 위해 gateway system을 이용한 담배가루이 cDNA library 제작을 시도하였다. 첫 번째 방법으로 oligo d(T) primer를 사용하였을 때, 평균 약 1 kb의 insert와 $1.4{\times}10^4cfu$의 titer를 확인하였다. 그러나 insert size가 너무 커서 적절하지 않았다. 두 번째 방법으로 attB-N25 random primer를 이용하고, sonication을 6초 실시하여 다시 진행하였다. 그러나 확인되는 insert size는 다소 컸고, 몇몇은 insert가 너무 작아서 밴드가 확인 되지않았으며, $1.04{\times}10^54cfu$의 titer를 확인할 수 있었다. 세 번째 방법으로는 oligo d(T) primer를 이용하였고, sonication을 2초 실시하였다. 그 결과 300 bp~600 bp size의 insert가 확인되었으나, electro transformation을 사용한 첫번째, 두번째 방법에 비해 heat shock transformation을 사용하여 titer가 $5.2{\times}10^24cfu$로 매우 낮은 것을 확인 할 수 있었다. 결과적으로 cDNA library를 만들 때 먼저 random primer를 사용하여 First strand를 합성하여 poly A를 제거하고, 다음으로 sonication을 1초 실시하여 300~700 bp정도의 적절한 size의 insert를 생성하고, 마지막으로 electro-transformation을 실시하여 transformation 효율을 높인다면 VIGS vector에 적합한 cDNA library를 만들 수 있을 것으로 사료 된다.

• 한국작물학회지
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• 제58권2호
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• pp.119-127
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• 2013

The interaction between Agrobacterium and soybean has been studied at the transcriptome level but not at the metabolic level. However, it is necessary to investigate the difference in metabolites between susceptible and non-susceptible cultivars for high efficiency transformation. We investigated the difference in metabolites from sonicated soybean cotyledons of Korean cultivars and Bert cultivar. To identify difference in metabolites, sonicated extracts were analysed by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR/MS). The soybean cultivars were classified by susceptibility using green fluorescent protein expression. We found a difference in metabolites between the high susceptible and low susceptible cultivars. The FT-ICR/MS experimental m/z data of different metabolites were compared with theoretical m/z in KNApSAcK database. The candidate list was made using KNApSAcK and focused on phenolic compounds. These candidate metabolites are speculated to influence factors in the interaction. This list of candidates may be useful to investigate the interaction between Agrobacterium and plants to increase transformation efficiency.

• Journal of the korean society of oceanography
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• 제37권2호
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• pp.58-65
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• 2002

The study of microbial communities in sediments is impaired by the lack of reliable extraction methods. This study reports on the efficiency of recovery of a method for extracting bacteria, protists and diatoms from sandy sediments using a modified decant/fix method. The best extractions were achieved after fixation with a microtubule stabilising fixative and subsequent sonication for 80 seconds. We estimate that the efficiencies of recovery of bacteria and mixed heterotrophic flagellates were $96.4{\pm}3.5\%$ and $96.9{\pm}4.6\%$, respectively. Diatoms were recovered with an efficiency of 38-83% and varied considerably from species to species. This study suggests that the decant/fix method is effective in extracting small cells such as bacteria and heterotrophic flagellates, and that the efficiency of recovery of the method varies due to cell length and different types of organisms. When microbial carbon biomass had been underestimated by up to 32%, with much of that relating to larger cells such as microalgae and ciliates. We note that the corrected abundances may be still a subset of the total numbers present.

• Bulletin of the Korean Chemical Society
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• 제32권5호
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• pp.1547-1553
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• 2011

An effective analytical method of gas chromatography/mass spectrometry (GC/MS) was developed for the rapid determination of essential oils in the crude extract of Acorus species (Acorus gramineus, Acorus tatarinowii, and Acorus calamus). Major phenypropanoids (${\beta}$,${\alpha}$-asarone isomers, euasarone, and methyleugenol) and ${\beta}$-caryophyllene in Acorus species were used as marker compounds and determined for the quality control of herbal medicines. To extract marker compounds, various extraction techniques such as solvent immersion, mechanical shaking, and sonication were compared, and the greatest efficiency was observed with sonication extraction using petroleum ether. The dynamic range of the GC/MS method depended on the specific analyte; acceptable quantification was obtained between 10 and 2000 ${\mu}g/mL$ for ${\beta}$-asarone, 10 and 500 ${\mu}g/mL$ for ${\alpha}$-asarone, 10 and 200 ${\mu}g/mL$ for methyleugenol, and between 5 and 100 ${\mu}g/mL$ for ${\beta}$-caryophyllene. The method was deemed satisfactory by inter- and intra-day validation and exhibited both high accuracy and precision, with a relative standard deviation < 10%. Overall limits of detection were approximately 0.34-0.83 ${\mu}g/mL$, with a standard deviation (${\sigma}$)-to-calibration slope (s) ratio (${\sigma}$/s) of 3. The limit of quantitation in our experiments was approximately 1.13-3.20 ${\mu}g/mL$ at a ${\sigma}$/s of 10. On the basement of method validation, 20 samples of Acorus species collected from markets in Korea were monitored for the quality control. In addition, principal component analysis (PCA) and hierarchical cluster analysis (HCA) were performed on the analytical data of 20 different Acorus species samples in order to classify samples that were collected from different regions.

• 한국물환경학회지
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• 제32권6호
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• pp.520-527
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• 2016

Phycocyanin (PC) is one of the water-soluble accessory pigments of cyanobacteria species, and its concentration is used to estimate the presence and relative abundance of cyanobacteria. In laboratory experiments, PC content of field data were determined using Sarada's freeze-thaw method in algal bloom season. The effectiveness of three selected extraction methods (repeated freeze-thaw method, homogenization, power control) for PC were determined. The extraction efficiency of phycocyanin was the highest (of the methods compared) when a single freezing-thawing cycle was followed by pre-sonication. Applying this optimized method to surface water of Korean inland waters, the average concentration distribution was estimated at $2.9{\sim}51.9mg/m^3$. It has been shown that the optimized pre-sonication method is suitable to measure cyanobacteria PC content for the characterization of inland waters. The approach and results of this study indicates the potential of effective methods for remote monitoring and management of water quality in turbid inland waters using hyperspectral remote sensing.

• 한국지하수토양환경학회지:지하수토양환경
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• 제12권5호
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• pp.73-85
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• 2007

본 연구에서는 액상에서 EGBE, DGBE, DBM, TGME의 효율적인 분석을 위해 이용되던 액상추출법을 대신할 수 있는 방법으로 GC/FID를 이용한 SPME법 실험 연구를 진행하였다. 그리고 실험계획법(DOE)을 사용하여 EGBE를 포함한 디젤첨가제 미량분석의 최적조건을 설명하였다. 실험은 통계분석결과 뿐만 아니라 요인 수의 최적화에 따른 중심합성설계에 의한 완전요인 설계법을 사용하였다. 반응표면분석은 추출 효율이 주 영향인 염농도, 흡착 온도, 흡착 시간과 sonication 시간에 따른 2차 다항식에 의해 설명될 수 있음을 보여주었다. 실험계획법(DOE)을 사용하는 것은 액상 시료에서 디젤첨가제의 정량분석을 개선하는 자료분석법이 될 것이다.