• 제목/요약/키워드: H.235

검색결과 480건 처리시간 0.032초

Studies on the Relationship of the Preparation of Thiamine Derivatives (Thiamine 유도체(誘導體)의 제조조건(製造條件)에 관(關)한 연구(硏究))

  • Park, Hong-Koo;Cho, Han-Ok;Cho, Sung-Hwan
    • Applied Biological Chemistry
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    • 제23권2호
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    • pp.123-130
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    • 1980
  • Thiamine derivatives of thiamine tetrahydrofurfuryl disulfide (TTFD) and thiamine propyl disulfide (TPD) were obtained in a good yield and purity by use of thiothiamine $(SB_1)$ and also described in details for the preparing sodium tetrahydrofurfuryl thiosulphate (Bunte's salt) with and without KI. The optimum reaction conditions for the preparation of TTFD was set in which the Box-Wilson plan was applied. The reaction conditions are as follows; 1. pH value of aqueous solution of thiol type of $B_1{\cdot}HCl;12.09$ 2. Quantity of Bunte's salt (to $B_1{\cdot}HCl\;20G$); 35.01g 3. Reaction temperature; $15.59^{\circ}C$ Studies on ultraviolet absorption were made at various pH and showed that the absorption maxima are shifted with change of pH. The absorption maxima are at $244{\sim}246nm,\;234{\sim}235nm$ in TTFD, and $245{\sim}246nm,\;233{\sim}235nm$ in TPD. The structure was proved by the infrared spectral evidence. Quantitative determination was studied.

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Optimization of GMAW Process Parameters to Improve the Length of Penetration in EN 10025 S 235 Grade

  • Deshpande, M.U.;Kshirsagar, J.M.;Dharmadhikari, Dr. H.M.
    • Journal of Welding and Joining
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    • 제35권1호
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    • pp.74-78
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    • 2017
  • In auto ancillary fabrication industry, GMAW is a very useful & important welding process and EN10025 S 235 Grade is common material used for manufacturing of two wheeler chassis. This research gives the detail influence of welding process parameters such as welding current, welding voltage, wire speed on the penetration in EN10025 S 235 Grade mild steel material. The experimentation of this research has been carried out by using three factors, three level Taguchi DOE method. To analyze & optimize the welding parameters & characteristics, analysis of variance, L9 orthogonal array & signal to noise ratio are used. Length of Penetration in addition to the depth of penetration is major concern in fillet welded joints, as the penetration decides the strength of the welded joint. After analysis of penetration in all 9 welded samples, optimize parameters readings verified & found probability value within 0.05.From this research it is come to know that welding current & welding voltage is major parameters which affects the penetration in welded joints.

Fabrication of Mullite Short Fibers from Coal Fly Ash (석탄회로부터 뮬라이트 단섬유의 제조)

  • Kim, Byung-Moon;Park, Young-Min;Lyu, Seung-Woo;Yoon, Seog-Young;Park, Hong-Chae
    • Journal of the Korean Ceramic Society
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    • 제43권4호
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    • pp.235-241
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    • 2006
  • Mullite short fibers have been fabricated by adapting the Kneading-Drying-Calcination (KDC) process and characterized. The effect of the addition of foaming agent and calcination temperature on the formation of mullite fibers from coal fly ash, was examined. In the present work, ammonium alum $NH_4Al(SO_4)_2\;12H_2O$ synthesized trom coal fly ash and sodium phosphate $Na_2HPO_4\;2H_2O$ were used as foaming agents. After calcination at $1300^{\circ}C$ for 10 h and then etching with 20% HF solution at $50^{\circ}C$ for 5 h using a microwave heating source, the alumina-deficient $(AI_2O_3/SiO_2$ = 1.13, molar ratio) orthorhombic mullite fibers with a width of ${\sim}0.8mm$ (aspect ratio >30), were prepared from the coal fly ash with $AI_2O_3/SiO_2$ = 0.32, molar ratio by the addition of $NH_4AI(SO_4)_2\;12H_2O$, and with further addition of 2 wt% sodium phosphate. The excessive addition of sodium phosphate rather decreased the formation of mullite fibers, possibly due to the large amount of liquid phase prior to mullitization reaction.

Growth of Dendranthema zawadskii in Chloride-containing De-icing Salt Areas Upon Treatment With Soil Amendments (제설제 피해지에서 토양개량제 처리에 따른 구절초의 생육특성 비교)

  • Ju, Jin-Hee;Yang, Ji;Park, Sun-Young;Yoon, Yong-Han
    • Journal of Environmental Science International
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    • 제30권3호
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    • pp.235-243
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    • 2021
  • This study was conducted to investigate the growth of Dendranthema zawadskii in damaged soils when they are treated with improvement agents. The treatments consisted of a control (unamended field soil) and the application of a loess ball of 1 cm to the field soil. According to the degree of damage the de-icing agent had caused, the soils were divided into 3 areas (based on the yellowing of Pinus densiflora for. multicaulis in soil surveys): H (high saline), M (medium saline), and L (low saline). A total of six treatments were performed: D. zawadskiia plant without soil amendment (H; high saline soil, M; medium saline soil, L; low saline soil), and a D. zawadskiia plant with loess ball on the soil surface (H.L; high saline soil with loess ball, M.L; medium saline soil with loess ball, L.L; low saline soil with loess ball). The results showed that D. zawadskiia growth went from highest to lowest in the order: M.L > L.L > M > L > H.L > H. Plant growth results showed that soils treated with soil amendments (loess ball) were better for D. zawadskii growth than untreated soils.

Impedance Analysis and Surge Characteristics of PV Array

  • Lee K.O.;So J.H.;Jung M.W;Yu G.J.;Choi J. Y.;Ah H.S.
    • Proceedings of the KIPE Conference
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    • 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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    • pp.235-238
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    • 2003
  • Photovoltaic(PV) array, which is generally installed outside, has the possibility to be damaged by high voltage due to lightning. Because the surge characteristics of PV array have not b eon fully Identified yet, there is a very important issue whether PV array should be connected with ground or not. In this paper, a basic model of PV array is provided considering the PV cell's barrier capacitance and ground capacitance for analysis of surge characteristics.

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