• Journal of the Korean Wood Science and Technology
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• 제44권3호
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• pp.360-369
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• 2016

본 연구에서는 팜 부산물인 Empty Fruit Bunch (EFB)의 연료적 특성을 향상시키기 위해 용탈처리와 습식 반탄화를 연속적으로 수행하였다. 용탈처리는 $25{\sim}90^{\circ}C$에서 5~30분 수행하였으며, $90^{\circ}C$, 10분 조건에서 55.99%의 가장 높은 회분 감소율을 나타냈다. 회분 감소율은 용탈 시간보다 온도에 따라 영향을 받았다. 용탈처리 후 연속적으로 습식 반탄화를 수행하였으며 반응온도 $180{\sim}200^{\circ}C$, 반응시간 5~40분에서 실시하였다. 연속처리에 의해 규소를 제외한 대부분의 무기성분은 제거되었으며 회분 감소율은 41.05~63.58%로 나타났다. 특히, 염소, 칼륨, 마그네슘, 인 성분은 80%이상 제거되었다. 용탈처리 후 $200^{\circ}C$, 40분에서 습식 반탄화를 수행한 결과 발열량은 원시료(4390 kcal/kg)와 비교하여 7.96% 증가한 4736 kcal/kg를 나타냈다.

• 한국수산과학회지
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• 제36권3호
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• pp.210-219
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• 2003

To develop natural flavoring substances, optimal two stage enzyme hydrolysis conditions and flavor compounds of short-neck clam (Tapes philippinarum) enzyme hydrolysates were examined. The optimal enzyme hydrolysis conditions for two stage enzyme hydrolysate (TSEH) of short-neck clam were revealed in temperature at $55^{\circ}C$ for 4 hours digestion with alcalase at the 1st stage and 4 hours digestion at $45^{\circ}C$ with exopeptidase type neutrase at the 2nd stage. In quality tests of hot-water extracts, steam extracts and 4 kinds of enzyme hydrolysates, TSEH processing method was superior to other methods in yield, nitrogen contents, organoleptic taste such as umami intensity and inhibition of off-flavor formation, and transparency of extract. Total free amino acid contents in hot-water extract, steam extract and TSEH were 1,352.1 mg/100 g, 1,174.1 mg/100 g and 2,122.4 mg/100 g, respectively, Major free amino acids in TSEH were glutamic acid, glycine, alanine, tyrosine, phenylalanine and arginine. As for nucleotides and other bases, betaine, TMAO and creatinine were principal components in TSEH. The major inorganic ions in TSEH were Na, K, P and Cl. TSEH also revealed very higher angiotensin-I converting enzyme inhibition effect $(70.7\%)$ than those of hot-water and steam extract. We conclude that TSEH from short-neck clam was more flavorable compared with the seasoning materials on the market, it could be utilized as the instant soup base and the seasoning substances for fisheries processing.

• Bulletin of the Korean Chemical Society
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• 제35권11호
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• pp.3275-3279
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• 2014

A mass balance method for purity assessment of thermolabile organic reference materials was established by combining several techniques, including liquid chromatography with UV/VIS detector (LC-UV), Karl-Fischer (K-F) Coulometry, and thermal gravimetric analysis (TGA). This method was applied to three fluoroquinolones like enrofloxacin, norfloxacin and ciprofloxacin. LC-UV was used to analyze structurally related organic impurities based on UV/VIS absorbance spectra obtained in combination with LC separation. For all three organic reference materials, the UV/VIS spectra of the separated impurities were similar to that of the major component of the corresponding materials. This indicates that the impurities are structurally related to the respective reference material sharing common chromophores. Impurities could be quantified by comparing their absorbances at the wavelength of maximum absorbance (${\lambda}_{max}$). The water contents of the reference materials were measured by K-F Coulometry by an oven-drying method. The total inorganic impurities contents were assayed from ash residues in TGA analysis with using air as a reagent gas. The final purities estimated from results of those analytical techniques were assigned as ($99.91{\pm}0.06$), ($97.09{\pm}0.17$) and ($91.85{\pm}0.17$)% (kg/kg) for enrofloxacin, norfloxacin and ciprofloxacin, respectively. The assigned final purities would be applied to the reference materials which will be used as calibrators for the certification of those compounds in matrix CRMs as starting points for the traceability of their certified values to SI units.

• 한국환경보건학회지
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• 제40권2호
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• pp.105-113
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• 2014

Objectives: It is necessary to apply quantitative structure activity relationship (QSAR) for the various chemicals with insufficient toxicity data that are used in the workplace, based on the precautionary principle. This study aims to find application plan of QSAR software tool for predicting health hazards such as genetic toxicity, and carcinogenicity for some chemicals used in the electronics industries. Methods: Toxicity prediction of 21 chemicals such as 5-aminotetrazole, ethyl lactate, digallium trioxide, etc. used in electronics industries was assessed by Toxicity Prediction by Komputer Assisted Technology (TOPKAT). In order to identify the suitability and reliability of carcinogenicity prediction, 25 chemicals such as 4-aminobiphenyl, ethylene oxide, etc. which are classified as Group 1 carcinogens by the International Agency for Research on Cancer (IARC) were selected. Results: Among 21 chemicals, we obtained prediction results for 5 carcinogens, 8 non-carcinogens and 8 unpredictability chemicals. On the other hand, the carcinogenic potential of 5 carcinogens was found to be low by relevant research testing data and Oncologic TM tool. Seven of the 25 carcinogens (IARC Group 1) were wrongly predicted as non-carcinogens (false negative rate: 36.8%). We confirmed that the prediction error could be improved by combining genetic toxicity information such as mutagenicity. Conclusions: Some compounds, including inorganic chemicals and polymers, were still limited for applying toxicity prediction program. Carcinogenicity prediction may be further improved by conducting cross-validation of various toxicity prediction programs, or application of the theoretical molecular descriptors.

• 대한가정학회지
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• 제27권2호
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• pp.75-83
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• 1989

In this study, effect of heat treatment on phytic acid, phosphorus compounds, and minerals in Korean soybean varieties was investigated. Results were summarized as follwo: 1. In the soybeans tested, protein content ranged from 34.6 to 44.6%, lipid content from 15.4 to 20.2%, fiber content from 4.8 to 6.1% and ash content from 4.5 to 5.9%. 2. Content range for phytic acid in soybean varieties was 1,300 to 1,542mg/100g and its mean was measured 1,392mg/100g. With increasing of the temperature, the phytic acid tends to be destroyed, especially at 6$0^{\circ}C$ the loss was averaged about 20%. 3. Total phosphorus content in soybean ranged from 607 to 681mg/100g and the decending order of phosphors content in soybean varieties was Millyang > Hwangkeum > Kwangkyo > Danyoup > Hill > Jangyoup. It was also destroyed with increasing temperature. 4. Phytate phosphorus content range in soybean was from 315.6 to 318.0mg/100g and decreased with increasing temperature. 5. Inorganic phosphorus content ranged from 95.5 to 110.0mg/100g and it was increased by temperature rising among soybean varieties. 6. Phytate phosphorus to total phosphorus ratio ranged from 5.2 to 5.7 and decreased by temperature rising. 7. The content of nonphytate phosphorus varied widely between soybean varieties and decreased with temperature increase. 8. The content of calcium, iron and magnesium ranged from 15.7 to 25.7mg/100g from 8.8 to 16.8mg/100g and from 121.9 to 143.6mg/100g respectively. The content of Mg showed small difference among soybean varieties. The change of mineral content with heat treatment in soybean did not give any meaningful change mineral content.

• Carbon letters
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• 제3권1호
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• pp.1-5
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• 2002

The regional bio-wastes available in abundance in India were converted into porous carbon by heat treatment at different temperatures from $650-950^{\circ}C$. The wood retain shapes after pyrolysis though shrinkage occured both in axial and radial directions. The shrinkage in radial direction was found to be more than in axial direction in all woods. The density of woods and chars from these at a given temperature has been found to follow linear relationship. Chars were steam activated at temperature $700-800^{\circ}C$ for different times between 45-240 min. Both the temperature and time of activation with steam has a profound effect on surface area. Chars from softwoods like bagasse and castor oil plant were activated at lower temperature, i.e. $700-750^{\circ}C$ whereas hard wood chars have to be activated at higher temperature around $800^{\circ}C$. The morphology of wood as well as of chars has been studied by SEM. The comparison of the two showed that the nature of porosity in chars depends on precursor morphology, nature and physical state of wood and presence of inorganic compounds in the wood. Hard wood results in cross inter connected pores while softwood leads to fibriller structure. The present studies show that activated carbon with reasonably good surface area (${\sim}1000m^2/gm$) can be prepared from soft wood bio-wastes like bagasse and castor oil plant, while surface area ${\sim}1370m^2/gm$ was achieved from hard wood bio waste of pine wood.

• 한국환경보건학회지
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• 제33권6호
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• pp.479-487
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• 2007

[ $PM_{2.5}$ ], particulate matter less than 2.5 um in a diameter, can penetrate deeply into the lungs. Exposure to $PM_{2.5}$ has been associated with increased hospital visits for respiratory aliments as well as increase mortality. $PM_{2.5}$ is a byproduct of combustion processes and as such has a complex composition including a variety of metallic elements, inorganic and organic compounds as well as biogenic materials (microorganisms, proteins, etc). In this study, the average concentrations of fine particulates $PM_{2.5}$ have been measured simultaneously in Asan and Seoul, Korea, by using particulate matter portable sampler from September 2001 to August 2002. Sample collection filters were analyzed by ICP-OES to determine the concentrations of metallic elements (As, Ni, Fe, Cr, Cd, Cu, Pb, Zn, Si). Annual mean $PM_{2.5}$ concentrations in Asan and Seoul were 37.70 and $45.83\;{\mu}g/m^3$, respectively. The highest concentrations of $PM_{2.5}$ were found in spring season in both cities and the concentrations of measured metallic elements except As in Asan were higher than those in Seoul, suggesting that yellow dust in spring could affect $PM_{2.5}$ concentrations in Asan rather than Seoul. The correlation coefficients of Pb and Zn were 0.343 for Asan and 0.813 for Seoul during non-yellow dust condition, suggesting that Pb and Zn were influenced with the same sources. The correlation coefficients between Si and Fe in the fine particulate mode were 0.999 (Asan) and 0.998 (Seoul) during yellow dust condition. It was suggested that these two elements were impacted by soil-related transport from China during the yellow dust storm condition.

• 청정기술
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• 제12권3호
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• pp.175-181
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• 2006

실내 공기오염 방지를 위하여 견운모와 규조토를 건축내장재로 사용하기 위한 물리 화학적 특성을 조사 하였다. 특히 규조토의 경우 주사전자현미경(Scanning Electron Microscope: SEM)으로 표면에 분포하는 규조화석의 존재를 확인하였으며, 질소흡탈착법(Brunauer-Emmett-Teller (BET) method)을 통해 5 nm 이하의 기공이 고르게 분포하고 비교적 넓은 비표면적을 가지는 것을 알 수 있었다. 이러한 규조토와 비교하여 견운모는 기공특성이 보이지 않았으며 비표면적 역시 상대적으로 작은 것으로 나타났다. 따라서, 다공질 구조와 넓은 비표면적으로 인해 규조토가 견운모보다 상대적으로 높은 흡착특성을 가지고 있음을 예상 하였으며, 이를 실험적으로 확인 하였다. 하지만 $950^{\circ}C$이상으로 열처리한 결과 규조토는 다공질 규조화석의 연소 및 무기성분의 고온소결로 인해 더 이상 기공 구조를 보이지 않고 비표면적이 감소하였으며, 그 결과 흡착성능 또한 감소하는 경향을 보였다. 결론적으로, 열처리 하지 않은 규조토의 경우 규조화석의 존재로 인해 다공질 구조를 가지며, 넓은 비표면적에 의해 보다 높은 암모니아 흡착특성을 보여 실제로 이와 같은 유해 화합물을 효과적으로 제거할 수 있는 능력이 있음을 보였다.

• Safety and Health at Work
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• 제2권3호
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• pp.229-235
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• 2011

Objectives: In this study, we summarized the External Quality Assessment Scheme (EQAS) for the biological monitoring of occupational exposure to toxic chemicals which started in 1995 and continued until a $31^{st}$ round robin in the spring of 2010. The program was performed twice per year until 2009, and this was changed to once a year since 2010. The objective of the program is to ensure the reliability of the data related to biological monitoring from analytical laboratories. Methods: One hundred and eighteen laboratories participated in the $31^{st}$ round robin. The program offers 5 items for inorganic analysis: lead in blood, cadmium in blood, manganese in blood, cadmium in urine, and mercury in urine. It also offers 10 items for organic analysis, including hippuric acid, methylhippuric acid, mandelic acid, phenylglyoxylic acid, N-methylformamide, N-methylacetamide, trichloroacetic acid, total trichloro-compounds, trans,trans-muconic acid, and 2,5-hexanedione in urine. Target values were determined by statistical analysis using consensus values. All the data, such as chromatograms and calibration curves, were reviewed by the committee. Results: The proficiency rate was below 70% prior to the first round robin and improved to over 90% for common items, such as PbB and HA, while those for other items still remained in the range of 60-90% and need to be improved up to 90%. Conclusion: The EQAS has taken a primary role in improving the reliability of analytical data. A total quality assurance scheme is suggested, including the validation of technical documentation for the whole analytical procedure.

• 한국토양환경학회지
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• 제1권1호
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• pp.81-88
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• 1996

토양과 토양용액의 경계면에서 토양내 흡착부위에 대해 경쟁적 이온이 존재할 때 카드늄의 흡착 현상을 연구하기 위하여, 토양의 Bt층으로부터 토양시료를 채취하여 토양의 물리화학적 특성을 분석하였다. 한편 Ethy-lone glycol monoethyl ether(EGME)와 질소가스를 가지고 각각의 토양의 특정표면적을 조사하였다. 토양층 내에서 토양입자와 반응성을 지닌 물질의 동태를 연구하는 일반적 지침으로, 물리화학적 특성이 완전히 다른 토양을 가지고 일반적인 등온흡착곡선을 취하였다. 단일 등온흡착곡선에서 보여 주었던 것처럼 물질간의 경쟁적흡착을 포함한 여러가지의 물리 화학적 요인들이 흡착에 영향을 미칠 것으로 추정된다. 한편 각각의 토양입자에 의한 카드늄 흡착의 정도는 사용된 토양과 용액의 회석 비율뿐만 아니라 각각의 토양의 표면적에 의존한다는 것을 알 수 있었다. 이러한 결과는 서로 다른 토양에서의 카드늄이 마그네시움과의 경쟁적 흡착에서도 적용되는 것을 알 수 있었다. 이러한 등온흡착곡선은 유해한 무기성분의 흡착과 동태 해석 뿐만 아니라 표준 배취흡착과정을 연구개발하는데 복합 요인으로 작용한다는 것을 증명하기 위한 예로서 사용할 수 있다.