• Journal of Information Processing Systems
• /
• 제8권4호
• /
• pp.693-712
• /
• 2012

The paper presents three machine learning based keyphrase extraction methods that respectively use Decision Trees, Na$\ddot{i}$ve Bayes, and Artificial Neural Networks for keyphrase extraction. We consider keyphrases as being phrases that consist of one or more words and as representing the important concepts in a text document. The three machine learning based keyphrase extraction methods that we use for experimentation have been compared with a publicly available keyphrase extraction system called KEA. The experimental results show that the Neural Network based keyphrase extraction method outperforms two other keyphrase extraction methods that use the Decision Tree and Na$\ddot{i}$ve Bayes. The results also show that the Neural Network based method performs better than KEA.

• 분석과학
• /
• 제11권5호
• /
• pp.321-331
• /
• 1998

기체크로마토그래피/질량분석법(GC/MS)을 이용하여 물시료 중에 미량으로 함유된 19종의 여러고리방향족탄화수소류에 대한 액체-액체 추출법, disk추출법 및 고체상 추출법을 이용한 시료 매트릭스로부터 분리, 추출하는 방법을 조사하였다. GC/MS의 오븐온도프로그램을 $80{\sim}310^{\circ}C$까지 단계적으로 변화시킨 결과 19종의 PAH류를 분리할 수 있었다. 액체-액체 추출법에 의한 물시료 중 PAH류의 회수율은 71.3~109.5% 범위로 나타났고, filtration에 의한 $C_{18}$ disk추출법의 회수율은 80.7~94.9% 범위로 높게 나타났다. 그러나 $C_{18}$ Sep-Pak을 사용한 고체상 추출법의 회수율은 51.8~77.9%범위이었다. 이상의 추출법에 대한 추출 회수율, 재현성 및 실험의 편리성 등 장단점을 비교한 결과, $C_{18}$ disk를 사용한 거르기법이 PAH류의 추출에 가장 적합한 방법임을 확인하였다. 각 추출법의 검출한계(S/N=5)는 액체-액체 추출법 및 고체상 추출법의 경우 0.25~6.25 ppb, disk추출법은 0.05~1.25 ppb 범위이었다.

• Journal of Ginseng Research
• /
• 제37권4호
• /
• pp.468-474
• /
• 2013

Ginseng seed oil was prepared using compressed, solvent, and supercritical fluid extraction methods of ginseng seeds, and the extraction yield, color, phenolic compounds, fatty acid contents, and phytosterol contents of the ginseng seed oil were analyzed. Yields were different depending on the roasting pretreatment and extraction method. Among the extraction methods, the yield of ginseng seed oil from supercritical fluid extraction under the conditions of 500 bar and $65^{\circ}C$ was the highest, at 17.48%. Color was not different based on the extraction method, but the b-value increased as the roasting time for compression extraction was increased. The b-values of ginseng seed oil following supercritical fluid extraction were 3.54 to 15.6 and those following compression extraction after roasting treatment at $200^{\circ}C$ for 30 min, were 20.49, which was the highest value. The result of the phenolic compounds composition showed the presence of gentisic acid, vanillic acid, ferulic acid, and cinnamic acid in the ginseng seed oil. No differences were detected in phenolic acid levels in ginseng seed oil extracted by compression extraction or solvent extraction, but vanillic acid tended to decrease as extraction pressure and temperature were increased for seed oil extracted by a supercritical fluid extraction method. The fatty acid composition of ginseng seed oil was not different based on the extraction method, and unsaturated fatty acids were >90% of all fatty acids, among which, oleic acid was the highest at 80%. Phytosterol analysis showed that ${\beta}$-sitosterol and stigmasterol were detected. The phytosterol content of ginseng seed oil following supercritical fluid extraction was 100.4 to 135.5 mg/100 g, and the phytosterol content following compression extraction and solvent extraction was 71.8 to 80.9 mg/100 g.

• KSBB Journal
• /
• 제16권3호
• /
• pp.264-268
• /
• 2001

The extraction efficiencies of panaxynol and panaxydol were optimal at 80$^{\circ}C$ with soxhlet method. The extraction efficiencies increased up to 45$^{\circ}C$ with shaking method. Amounts of panaxynol and panaxydol were determined by gas chromatography. Extracted quantities of panaxynol and panaxydol using the shaking method increased over a period of 14 hours. The efficiencies of panaxynol and panaxydol extraction by soxhlet and shaking methods were higher for smaller particle sizes. Upon water swelling treatment, extraction efficiencies of panaxynol and panaxydol decreased gradually with time for both methods.

• 한국식품영양학회지
• /
• 제29권2호
• /
• pp.153-161
• /
• 2016

This study investigated the chemical composition of Solidago virga-aurea var. asiatica Nakai essential oils collected using different extraction methods. The essential oils obtained by simultaneous steam distillation extraction (SDE) and hydrodistillation extraction (HDE) methods from the aerial parts of Solidago virga-aurea var. asiatica Nakai were analyzed by GC and GC-MS. Ninety-nine volatile flavor compounds were identified in the essential oil produced from Solidago virga-aurea var. asiatica Nakai using the SDE method. These compounds were classified into eight categories in terms of chemical functionality: 26 hydrocarbons, 8 aldehydes, 36 alcohols, 7 ketones, 12 esters, 5 oxides and epixides, 4 acids, and a miscellaneous one. Spathulenol (15.66%) was the most abundant compound. Ninety-eight compounds including of 35 hydrocarbons, 6 aldehydes, 29 alcohols, 6 ketones, 10 esters, 4 oxides and epixides, 7 acids, and a miscellaneous one were identified in the essential oil from the plant using the HDE method. Hexadecanoic acid (24.74%) was the most abundant compound. The chemical composition of Solidago virga-aurea var. asiatica Nakai essential oils extracted by SDE and HDE methods are characterized by high content of sesquiterpene alcohols and acids, respectively. The extraction methods may be influenced in the chemical composition of natural plant essential oils.

• 대한한의학회지
• /
• 제34권4호
• /
• pp.12-20
• /
• 2013

Objectives: This study compared Gumiganghwal-tang (GGT) decoctions produced using different pressure levels for various extraction times to determine the optimal extraction conditions through hydrogen ion concentration (pH), total soluble solids content (TSSC), extraction yield, and content of chemical compounds. Methods: Decoctions were prepared by the pressure levels of 0 or $1kgf/cm^2$ for 30-180 min. The pH and TSSC were measured, the extraction yield was calculated, and the amounts of the chemical compounds were determined using high performance liquid chromatography. Results: The higher pressure and longer extraction time decreased the pH value, while those conditions increased TSSC and extraction yield: the decoction produced in 180 min by pressurized method showed the minimum value of pH, but maximum values of TSSC and extraction yield. The chemical compounds showed higher amounts in decoctions produced by non-pressurized methods than pressurized methods and their amounts were decreased over the peak extraction time in both pressurized and non-pressurized methods. The results of regression analysis confirmed the correlative influences of the pressure and extraction time on pH, TSSC, and extraction yield. Conclusions: This study suggests that pressure and extraction time influence the compositional constituents in GGT decoctions, and the non-pressurized method for 120 min should be chosen as the optimal extraction condition for the preparation of GGT decoction.

• 대한약침학회지
• /
• 제15권2호
• /
• pp.24-30
• /
• 2012

This study compared Ojeok-san (Wuji-san in Chinese) decoctions produced using different extraction methods for variable times. Decoctions were extracted in pressurized or non-pressurized conditions for 60, 120, and 180 mins. We investigated the Ojeok-san extract yield, the total soluble solid content, the hydrogen ion concentration (pH), and the reference compound content. The extract yield and the total soluble solid content were higher in decoctions produced by non-pressurized extraction; both were proportional to the extraction time. The pH tended to decrease as the extraction time was increased in decoctions produced using both methods. After 60 and 180 mins, the levels of albiflorin, paeoniflorin, nodakenin, naringin, and neohesperidin were significantly higher in decoctions extracted using the non-pressurized method compared with those extracted using the pressurized method. After 120 mins, only cinnamaldehyde was extracted in a greater amount in pressurized decoctions compared with non-pressurized decoctions. The levels of paeoniflorin, ferulic acid, nodakenin, naringin, hesperidin, neohesperidin, and glycyrrhizin increased with time in non-pressurized decoctions. This study showed that the use of pressurized and non-pressurized extraction methods for different times affected the composition of Ojeoksan (Wuji-san) decoctions.

• 한국환경과학회:학술대회논문집
• /
• 한국환경과학회 2003년도 International Symposium on Clean Environment
• /
• pp.119-122
• /
• 2003

Quantitation methods of total petroleum hydrocarbons to determinate oil contaminated level in soil were discussed. Extraction characteristics of several pretreatment methods and practical detection limit and reappearances in gas chromatography/mass spectrometry. with each pretreatment method were investigated. The obtained results showed that the newly adopted quantitation method and mechanical shaking extraction method using methanol with extraction solvent are more practical and applicable to real sample than the conventional methods. In applying these methods to gasoline, kerosene, fuel oil which are major source of soil contamination, the practical quantitation limit and % relative standard deviation was able to determine with range of 2.5 - 10 ppm, 5 - 7 ％.

• Food Science and Biotechnology
• /
• 제15권5호
• /
• pp.786-791
• /
• 2006

Three solvent extraction techniques were used to recover waxy tractions from grain sorghum kernels. Yield and chemical composition of the waxy tractions obtained by reflux, bench scale (recirculated solvent), and countercurrent extraction methods were compared. Waxy traction yield from countercurrent extraction (0.200%) was significantly greater (p<0.05) than the yields of wax from both reflux (0.184%) and bench-scale (0.179%) methods. The waxy traction extracted using the bench-scale method showed the greatest relative amount of long-chained (primarily C:28 and C:30) alcohols while the countercurrent-extracted wax showed the greatest relative amount of long-chained fatty acids and fatty aldehydes. Countercurrent extraction removed a higher additive percentage of fatty aldehydes, acids, and alcohols than reflux or bench-scale extraction method.

• Food Science and Biotechnology
• /
• 제18권2호
• /
• pp.565-569
• /
• 2009

This study was conducted to evaluate the effects of different preparation methods on the recovery and quantification of ginsenosides in raw Korean ginseng (Panax ginseng C.A. Meyer). Eight major ginsenosides ($Rb_1$, $Rb_2$, $Rb_3$, Rc, Rd, Re, Rf, and $Rg_1$) were analyzed by high performance liquid chromatography (HPLC), after which the recovery and repeatability of the extraction of those ginsenosides using 3 different preparation methods were compared [A. direct extraction (DE) method, hot MeOH extraction/evaporation/direct dissolution; B. solid phase extraction (SPE) method, hot MeOH extraction/evaporation/dissolution/$C_{18}$ cartridge adsorption/MeOH elution; C. liquid-liquid extraction (LLE) method, hot MeOH extraction/evaporation/dissolution/n-BuOH fractionation]. Use of the DE method resulted in a significantly higher recovery of total ginsenosides than other methods and a relatively clear peak resolution. Use of the SPE and LLE methods resulted in clearer peak resolution, but lower ginsenoside recovery than the DE method. The LLE method showed the lowest ginsenoside recovery and repeatability among the 3 methods. Given that the DE method employed only extraction, evaporation, and a dissolution step (avoiding complicate and time consuming purification), this technique may be an effective method for the preparation and quantification of ginsenosides from raw Korean ginseng.