• Journal of Environmental Science International
• /
• v.7 no.6
• /
• pp.753-759
• /
• 1998

In physical and reactive extraction of acrylic acid using various solvents the equilibrium characteristics of extraction were investigated. The degree of extraction in reactive extraction with Tri-n-octylamine(TOA) was 1.5~3 times than that in physical extraction. Distribution ratio was constant in methyl isobutyl ketone(MIBK) and n-butylacetate(n-BAc) but was increased with increasing the concentration of acrylic acid in benzene and chloroform. It can be explained by formation of dimers. Maximum extraction leadings of acrylic acid were three in benzene and were two in MIBK, chloroform and n-BAc, and it was found that acrylic acid was extracted as the form of $A_3$R In benzene and $A_2R$ in MIBK, chloroform and n-BAc. In effect of solvent, the degree of extraction was increased as he difference of solubility parameter of solvent and solute was decreased, and as dielectric constant of solvent was increased.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2005.04a
• /
• pp.242-246
• /
• 2005

The heavy metal analysis (Cd, Pb, Cu, Cr, Zn, Ni) with various extraction methods was performed using the certified sample and real soil sample. In case of the certified samples, $10.5{\sim}118%$ of recovery was showed with various ranges depend on the metal kinds and extraction methods. Also, the alkali-digestion method was showed the proper results by applying in hexavalent chromium. In case of real sample, compared to amounts of heavy metals extracted using 0.1N-HCl, those extracted using acid digestion are higher by $3{\sim}24$ times in Cu, $1.1{\sim}1.5$ times in Cd, $2{\sim}23$ times in Pb, $3{\sim}104$ times in Zn, $12{\sim}101$ times in Ni, $30{\sim}202$ times in Cr. There is no considerable difference between four acid digestion methods.

• Parasites, Hosts and Diseases
• /
• v.32 no.1
• /
• pp.7-12
• /
• 1994

A calf and 50 mice were infected with Cryptosporidium parvum and their fecal materials were collected and treated 10 ether extraction (EE), followed by discontinuous sucrose gradients (DSG) method. EE method was to remove some of fat or lipid from feces. Sediments were washed by centrifugation ($1,500{\;}{\times}{\;}g$ for 10 min., 3 times) In phosphate-buffered saline and then these washed sediments were sleeved sequentially through stainless steel screens with a final mesh of 250 ($61{\;}{\mu\textrm{m}}$ porosity) to remove other debris. After sieving, the materials were suspended in 2.5% potassium dlchromate solution. Oocysts were counted by using a hemocytometer and the recovery rate of pure oocysts was calculated on the basis of the count. Following centrifugation ($1,500{\;}{\times}{\;}g$ for 30 min.) by DSG method, most oocysts were recovered at the interface between a gravity of 1.103 and 1.064. The recovery rates of pure oocysts from the fecal suspension of the calf ($3.8{\;}{\times}{\;}10^7/ml$) and the mouse ($3.2{\;}{\times}{\;}10^6/ml$) treated with EE method were 81.6% and 51.6%, respectively. It is suggested that the recovery rate was dependent on the number of oocysts In each suspension treated with EE method. To get the 50% recovery rate, there must be more than $2{\;}{\times}{\;}10^6$ oocysts per ml of the fecal suspension treated with EE method. By the combination of the two methods it was possible to isolate C. parvum oocysts from normal feces of the calf and mouse as well as from dlarrhelc feces.

• The Korean Journal of Food And Nutrition
• /
• v.32 no.5
• /
• pp.401-407
• /
• 2019

This study compares and analyzes inorganic components of four different Pu-erh tea species consumed in Korea. The criteria for the inorganic components was based on the Royal Institute of Technology (KTH) recommendations. Out of the 19 general items: potassium, manganese, silicon and fluorine were detected in amounts exceeding the maximum allowable concentration by 5~23, 57~91, 1.6~1.8 and 9~18 times respectively. Out of the 15 potentially harmful elements: aluminum and nickel were exceeded the Maximum allowable concentration by 9~14 times and 0.8~1.2 times respectively. To reduce the concentration of inorganic elements in excess of the maximum allowable concentration, the extraction time of tea should be less than 1 minute in addition to limiting the amount. The amount of Pu-erh tea for extraction was about 0.1 g manganese, about 0.3 g potassium, about 0.5 g fluoride and about 2 g silicon. Therefore, the maximum amount of tea for extraction should be 0.1 g in regards to the safety of Pu-erh tea. Based on the recommended maximum daily intake of inorganic ingredients by the Ministry of Food and Drug Safety, it is desirable that the number of extractions be less than three.

• Korean Journal of Cognitive Science
• /
• v.22 no.4
• /
• pp.347-364
• /
• 2011

In this paper, we propose a automatic image bases extraction method for visual image reconstruction from brain activity using Non-negative Matrix Factorization (NMF). Image bases are basic elements to construct and present a visual image. Previous method used brain activity that evoked by predefined 361 image bases of four different sizes: $1{\times}1$, $2{\times}1$, $1{\times}2$, $2{\times}2$, and $2{\times}2$. Then the visual stimuli were reconstructed by linear combination of all the results from these image bases. While the previous method used 361 predefined image bases, the proposed method automatically extracts image bases which represent the image data efficiently. From the experiments, we found that the proposed method reconstructs the visual stimuli better than the previous method.

• The Journal of the Korea Contents Association
• /
• v.12 no.9
• /
• pp.9-15
• /
• 2012

A conventional event sentence extraction research doesn't learn the 3W features in the learning step and applies the rule on whether the 3W feature exists in the extraction step. This paper presents a sentence weight based event sentence extraction method that calculates the weight of the 3W features in the learning step and applies the weight of the 3W features in the extraction step. In the experimental result, we show that top 30% features by the $TF{\times}IDF$ weighting method is good in the feature filtering. In the real estate domain of the public issue, the performance of sentence weight based event sentence extraction method is improved by who and when of 3W features. Moreover, In the real estate domain of the public issue, the sentence weight based event sentence extraction method is better than the other machine learning based extraction method.

• ETRI Journal
• /
• v.25 no.2
• /
• pp.101-108
• /
• 2003

This paper proposes an improved vascular pattern extraction algorithm for person verification applications. The proposed direction-based vascular pattern extraction (DBVPE) algorithm is based on the directional information of vascular patterns. It applies two different filters to the input images: row vascular pattern extraction filter (RVPEF) for effective extraction of the abscissa vascular patterns and column vascular pattern extraction filter (CVPEF) for effective extraction of the ordinate vascular patterns. We use the combined output of both filters to obtain the final hand vascular patterns. Unlike the conventional hand vascular pattern extraction algorithm, the directional extraction approach prevents loss of the vascular pattern connectivity. To validate the DBVPE algorithm, we used a prototype system with a DSP processor. The prototype system shows approximately a three-times better false acceptance rate (FAR) than the conventional single filter algorithm.

• Journal of Environmental Science International
• /
• v.12 no.4
• /
• pp.447-459
• /
• 2003

This study was carried out to develop an efficient process far the elimination of phenol pollutant from soils. An microwave-assisted process (MAP) and a conventional Soxhlet extraction method (SEM) were employed to extract phenol from two types of soils. The effects of extraction methods, aged time of the spiked soil samples, extraction solvent and extraction time on the extraction performance were compared. Our results demonstrate that the recoveries from standard soil spiked were at least 10% higher fer MAP than these f3r the conventional Soxhlet. The extraction time by MAP requires significantly shelter time (1 min) than 15 h of the conventional Soxhlet. The recoveries from non-contaminated soil spiked with phenol were also almost identical f3r above results. The reduction of the extraction times with efficiency higher than that afforded by the conventional Soxhlet technique supports the suitability of the MAP method.

• Natural Product Sciences
• /
• v.25 no.2
• /
• pp.150-156
• /
• 2019

Conventional extraction of oil and azadirachtin, a botanical insecticide, from Azadirachta indica involves defatting the seeds and leaves using hexane followed by azadirachtin extraction with a polar solvent. In order to simplify the process while maintaining the yield we explored a binary extraction approach using Soxhlet extraction device and hexane and ethanol as non-polar and polar solvents at various ratios and extraction times. The highest oil and azadirachtin yields were obtained at 6 h extraction time using a 50:50 solvent mixture for both neem leaves (44.7 wt%, $720mg_{Aza}/kg_{leaves}$) and seeds (53.5 wt%, $1045mg_{Aza}/kg_{leaves}$), respectively.

• Preventive Nutrition and Food Science
• /
• v.13 no.4
• /
• pp.321-326
• /
• 2008

In order to improve the market competitiveness of the processed products of Undaria pinnatifida, various extraction conditions of Undaria pinnatifida were examined to determine the optimal conditions for the extraction of its valuable components. The highest level of alginic acid content was detected after 90 min of typical extraction or after 20 min of pressure extraction, after which the levels decreased slightly. The concentrations of reducing sugar and crude protein were also high after 90 min of typical extraction. Both alginic acid and reducing sugar were extracted in greater amounts using pressure extraction. The reducing sugar content was $2.8{\sim}3.2$ times higher using pressure extraction rather than typical extraction. Furthermore, the extraction results were superior with the, pressure extraction method. The appropriate temperature and duration of extraction were found to be $120^{\circ}C$ for 20 min. The use of a single enzyme yielded better results during extraction compared to the use of a mixture of enzymes. 20 min of pressure extraction followed by the addition of 0.1% pectinase and 2 hr of further extraction at $50^{\circ}C$ yielded high contents of alginic acid and reducing sugar from Undaria pinnatifida.