• Title/Summary/Keyword: Comparison of reducing characteristics

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Reaction of Diisobutylaluminum Hydride-Dimethyl Sulfide Complex with Selected Organic Compounds Containing Representative Functional Groups. Comparison of the Reducing Characteristics of Diisobutylaluminum Hydride and Its Dimethyl Sulfide Complex

  • Cha, Jin-Soon;Jeong, Min-Kyu;Kwon, Oh-Oun;Lee, Keung-Dong;Lee, Hyung-Soo
    • Bulletin of the Korean Chemical Society
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    • v.15 no.10
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    • pp.873-881
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    • 1994
  • The approximate rate and stoichiometry of the reaction of excess diisobutylaluminum hydride-dimethyl sulfide complex($DIBAH-SMe_2$) with organic compounds containing representative functional group under standardized conditions (toluene, $0{\circ}C$) were examined in order to define the reducing characterstics of the reagent and to compare the reducing power with DIBAH itself. In general, the reducing action of the complex is similar to that of DIBAH. However, the reducing power of the complex is weaker than that of DIBAH. All of the active hydrogen compounds including alcohols, amines, and thiols evolve hydrogen slowly. Aldehydes and ketones are reduced readily and quantitatively to give the corresponding alcohols. However, $DIBAH-SMe_2$ reduces carboxylic acids at a faster rate than DIBAH alone to the corresponding alcohols with a partial evolution of hydrogen. Similarly, acid chlorides, esters, and epoxides are readily reduced to the corresponding alcohols, but the reduction rate is much slower than that of DIBAH alone. Both primary aliphatic and aromatic amides examined evolve 1 equiv of hydrogen rapidly and are reduced slowly to the amines. Tertiary amides readily utilize 2 equiv of hydride for reduction. Nitriles consume 1 equiv of hydride rapidly but further hydride uptake is quite slow. Nitro compounds, azobenzene, and azoxybenzene are reduced moderately. Cyclohexanone oxime liberates ca. 0.8 equiv of hydrogen rapidly and is reduced to the N-hydroxylamine stage. Phenyl isocyanate is rapidly reduced to the imine stage, but further hydride uptake is quite sluggish. Pyridine reacts at a moderate rate with an uptake of one hydride in 48 h, while pyridine N-oxide reacts rapidly with consumption of 2 equiv of hydride for reduction in 6h. Similarly, disulfides and sulfoxide are readily reduced, whereas sulfide, sulfone, and sulfonic acid are inert to this reagent under these reaction conditions.

Effects of steaming and drying processing on Korean rice wine (Makgeolli) with deodeok (Codonopsis lanceolate)

  • Jeong, Minah;Lee, Kwang Yeon;Lee, Hyeon Gyu
    • Korean Journal of Food Science and Technology
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    • v.53 no.1
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    • pp.85-91
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    • 2021
  • The physicochemical properties of deodeok (Codonopsis lanceolate) was investigated in relation to the different steaming time and cycles of steaming and drying (S/D). Additionally, the quality characteristics of Makgeolli with different amount (0-0.45%) of steaming and drying deodeok (SD) were measured comparison to non-steaming and drying deodeok (NSD). L⁎ values of deodeok tended to decrease as the number of S/D cycles and steaming times increased, while BI showed the opposite trend for L⁎ values. Reducing sugar increased significantly from 1 to 3 S/D cycles and decreased thereafter (p<0.05). Also, processed with steaming for 4 h and 5 S/D cycles had the highest antioxidant properties. Principal component analysis (PCA) revealed that the S/D process notably influenced the properties of deodeok. Quality characteristics of Makgeolli showed that 0.45% SD resulted in higher antioxidant properties than control or NSD.

An Study on the Ubiquitous Homes Service for aged people (노인을 위한 유비쿼터스 홈 서비스)

  • Seoh, Dong-Yon;Song, Jeong-Hwa;Lee, Hyun-Soo
    • Proceeding of Spring/Autumn Annual Conference of KHA
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    • 2006.11a
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    • pp.149-154
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    • 2006
  • The purpose of this study is to introduce ubiquitous home services for the aged. In comparison with general ubiquitous homes, ubiquitous homes for the aged have two major characteristics. First, the service contents should be expanded and strengthened. Second, the services should be customized to each individuals. The primary objective of a ubiquitous home for the aged is health care. The three affordances for this objective are 1)prevention of sickness and reducing the speed of aging process, 2)technical assistance for disability, 3)recovering and enhancing the physical and cognitive function. For this purpose this paper analyses the characteristics of the aged and current ubiquitous technology and ubiquitous home service, thus providing an outline for ubiquitous services necessary for aged people.

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Cultivation and Characteristics of Licorice F1 (Glycyrrhiza glabra × G. uralensis) Lines

  • Lee, Sang-Hoon;Kim, Yeon Bok;Lee, Jeong-Min;Lee, Jeong-Hoon;Park, Chung-Berm;Bang, Jae-Wook;Choi, Hae-Woon;Hur, Yoonkang;Park, Chun-Geon
    • Horticultural Science & Technology
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    • v.35 no.2
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    • pp.276-286
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    • 2017
  • Licorice, a traditional Korean medicinal plant, is recognized for its main active ingredient, glycyrrhizin. The level of glycyrrhizin in Chinese licorice (Glycyrrhiza uralensis) is lower than the reference level (2.5%) set by the Korean Pharmacopoeia, reducing its value as a medicinal herb. In this study, we aimed to overcome this problem by generating an interspecific licorice hybrid by crossing European licorice (G. glabra) with Chinese licorice, resulting in the production of 32 $F_1$ lines. A comparison of genetic traits revealed variations in glycyrrhizin content among lines, ranging from 1.5 to 5.6%, with a mean value of 3.2%; these values are higher than that of the parental plants. Additionally, 25 lines (78.1%) had a glycyrrhizin content greater than 2.5%, which is higher than the reference level set by the Korean Pharmacopoeia. Four of these lines had glycyrrhizin levels higher than the WHO recommended level of 4.0%. A comparison of phenotypic characteristics showed that the leaves of the hybrids possessed all of the characteristics of European and Chinese licorice; however, the stems of most hybrids had characteristics of European licorice. Finally, we determined the genetic distances of 34 samples of Glycyrrhiza plants (parents, 32 $F_1$ lines) by random amplified polymorphic DNA (RAPD); the $F_1$ lines showed a close genetic distance. We plan to develop to a cultivar using five of these lines (glycyrrhizin content < 4.0%).

Relationship between Drinking Behavior and Drinking Drive among Koreans (음주행태와 음주운전에 관한 관련성 분석)

  • Park Young-Mi;Kim Kwang-Kee;Kim Hyeon-Suk
    • Korean Journal of Health Education and Promotion
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    • v.23 no.1
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    • pp.45-61
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    • 2006
  • Objective: Drinking drive is a nationally recognized social problem. This research aimed to describe the relationship between drinking behavior and drinking drive based on the social demographic characteristics. Methods: This paper used secondary data for analyses which was derived from the national representative samples of adults; National Health and Nutrition Surveys by Korea Institute for Health and Social Affairs in 1998 and 2001. For data analyses, univariate analysis, Chi-square test and logistic regression analysis were adopted for the samples of male adults who were driving and 20 years old and more. Results: The prevalence of drinking drive varied significantly among socio-demographic characteristics. The year prevalence rates of drinking drive were 29.1% in 1998 and 16.4% in 2001. In the rates of drinking drive, males were higher than those of females in both years. By age, twenties to thirties showed the highest ratio of drinking drive(odd ratio=18.8), compared with the sixties. Related to the occupation, the persons who were engaging in farming and fishery showed the highest ratio(odd ratio=3.73) of drinking drive in comparison to the unemployed. Conclusions: People who drink alcohol frequently tended to have more experiences of drinking drive. In addition, the drivers who drink more amount of alcohol drinking were significantly associated with higher rates of drinking drive, as well. Strategy based on the socio-demographic characteristics may provide a promising prevention of reducing drinking drive. Community-based efforts, education, self-awareness and public-awareness to address drinking and drinking drive problems are effective in reducing drinking drive. Enacting comprehensive regulations which control drinking drive can reduce both alcohol use and drinking drive.

Comparison of Spray Characteristics of n-Heptane and Propane Using Spray Visualization in Direct Injection System (분무 가시화를 통한 직분사 시스템에서 n-heptane및 propane의 분무발달특성 비교)

  • Junkyu Park;Sungwook Park
    • Journal of ILASS-Korea
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    • v.28 no.1
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    • pp.32-42
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    • 2023
  • In this study, spray characteristics of n-heptane and propane were investigated under different injection pressure using various imaging techniques such as Mie-scattering, DBI (diffuse back-illumination), and Schlieren imaging techniques. NI compact RIO system was used to control a test injector. Spray penetration length, length-to-width ratio and number of black pixels were calculated by using MATLAB software to compare spray characteristics of each fuel. Longer spray penetration length and higher length-to-width ratio were observed in propane spray because of flash boiling caused by high saturated vapor pressure. Spray collapse occurred in propane spray due to the high plume-to-plume interaction. Moreover, rapid evaporation occurred in propane spray, so that nozzle tip wetting could not be observed. Rapid evaporation of propane also caused fewer residual droplets compared to n-heptane spray. Therefore, propane is advantageous in reducing the generation of soot emission from large droplets that are not atomized. However, additional evaluation should be conducted considering combustion efficiency and the possibility of deposits by nozzle tip icing during fuel injection.

Comparison of Quality of Model Tomato Sauces Produced with Different Mixture Ratios of Fresh Tomatoes and Canned Tomatoes (신선한 토마토와 통조림 토마토의 배합 비율을 달리하여 제조한 모델 토마토 소스의 품질 비교)

  • Ha, Dae-Joong;Kwak, Eun-Jung
    • Journal of the East Asian Society of Dietary Life
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    • v.19 no.5
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    • pp.791-797
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    • 2009
  • We investigated the quality and sensory characteristics of model tomato sauces which was made from fresh Vitaking tomatoes and American canned tomatoes in the mixture ratios of 0:100% ($S_1$), 25:75% ($S_2$), 50:50% ($S_3$), 75:25% ($S_4$) and 100:0% ($S_5$). Soluble solids, reducing sugars, vitamin C and organic acids increased as the contents of fresh tomatoes increased. pH and contents of $\beta$-carotene and lycopene decreased as the contents of fresh tomatoes increased. Lightness(L value) and yellowness (b value) increased as the contents of fresh tomatoes increased whereas redness (a value) didn't show any significant differences among samples. In the preference test, $S_3$ was the most preferred in red color, taste and overall preference. In the descriptive test, $S_1$ ranked the highest in redness, viscosity, palatability and flavor except for sweet and sour taste. $S_5$ was the lowest in redness, viscosity and palatability, being the highest in sour taste. From this result, we found that the mixture ratio of half fresh tomatoes and canned tomatoes was the best condition to make tomato sauce with preferred red color.

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Effect of Cereals on the Physicochemical and Sensory Characteristics of Noti - ll. Study on the Physicochemical and Sensory Characteristics of Glutinous millet Noti - (노티의 재료에 따른 이화학적, 관능적 및 기계적 특성 연구 -제 2보: 차조 노티의 이화학적, 관능적 및 기계적 특성 연구-)

  • 임희정;염초애
    • Korean journal of food and cookery science
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    • v.12 no.2
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    • pp.166-177
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    • 1996
  • This study was undertaken to investigate the effect of cereals on the physicochemical and sensory characteristics of Noti. Noti is one of Korean traditional pan-fried glutinous cereal cakes. In this case, Noti was made from the steamed glutinous millet flour Aspergillus and Penicillium developed in glutinous millet Noti dough from 40th day. The reducing sugar content of glutinous millet Noti was higher than that of the Noti dough during the same period and almost similar as the first day even 90 day storage. The moisture content of glutinous millet Noti was less than 20%. Moisture content of glutinous millet Noti to compare with the common rice cake was from 1/2 to 1/3. While gelatinization degree significantly decreased in the rice cake that did not add malt, glutinous millet Noti did not show decreasing gelatinization degree in comparison with the common rice cake. Overall acceptability was to add 15% malt and keep 6 hr saccharification time at 60$^{\circ}C$. The hard ness of glutinous millet Noti by Instron measurement was slowly increased after the l0th day. Cohesiveness and elasticity were increased during the period of storage.

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Comparison of Physicochemical Properties of Extruded Ginseng Samples

  • Ji, Yan-Qing;Yang, Hye-Jin;Tie, Jin;Kim, Mi-Hwan;Ryu, Gi-Hyung
    • Preventive Nutrition and Food Science
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    • v.13 no.4
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    • pp.299-305
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    • 2008
  • This study compared the physicochemical properties of root hair of white ginseng (WG), root hair of tissue cultured mountain ginseng (MG), root hair of red ginseng (RG) and extruded ginseng samples. The comparison of crude ash and total sugar resulted insignificant differences between extruded and raw samples. MG had a higher content of crude ash, crude protein, amino acids and polyphenolic compound than WG and RG; the total sugar and reducing sugar were highest in RG. Crude fat and acidic polysaccharide in RG and WG were similar to and higher than MG. Crude saponin of treated samples WG1 (moisture content 25%, barrel temperature $110^{\circ}C$) and WG3 (moisture content 35%, barrel temperature $110^{\circ}C$) were 9.80% and 9.73%, respectively, which were the highest among ginseng samples. In conclusion, the extrusion process can be applied to red ginseng manufacturing, and some characteristics of MG were higher than in RG and WG.

A Study on the Performance Comparison of 3D File Formats on the Web

  • Lee, Geon-hee;Choi, Pyeong-ho;Nam, Jeong-hwan;Han, Hwa-seop;Lee, Seung-hyun;Kwon, Soon-chul
    • International journal of advanced smart convergence
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    • v.8 no.1
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    • pp.65-74
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    • 2019
  • 3D file formats typically include OBJ (Wavefront file format), STL (STereoLithography), and FBX (Filmbox). Each format has limitations depending on its configuration and usage, and supported formats are different depending on the software application. glTF helps uniform integration of 3D file formats and allows for more efficient transmission of large 3D geometry files by organizing them in a binary format. This paper presents explanation on OBJ, FBX, and STL which are major examples of existing 3D file formats. It also explains the concept and characteristics of glTF and compares its performance with other 3D file formats on the web. The loading time and packets of each 3D file format are measured according to the web browser environment by means of Google Chrome, Firefox and Microsoft Edge. Experimental results show that glTF is the most efficient and that it exhibits the best performance. As to STL, relatively excessive traffic was observed. This study is expected to contribute to reducing rendering time on the web as 3D file formats are used.