• Title/Summary/Keyword: Alpha-particle

Search Result 386, Processing Time 0.024 seconds

A Study on the Manufacture of $\alpha$-Fe$_2$O (Major Material of Ferrite) by Waste Pickling Liquor of Steel (강철의 산세폐액으로부터 Ferrite의 주원료인 Fe$_3$O$_3$의 제조에 관한 연구)

  • 최석진
    • Journal of the Korean Ceramic Society
    • /
    • v.13 no.1
    • /
    • pp.25-29
    • /
    • 1976
  • The properties vary with quality of ferric-oxide that is major material of ferrites. In this point of view, a manufacturing method of pure and homogeneous fine ferric oxide is very important. The characters of this study are as follows: 1) Ferric oxide was made from waste pickling liquor of steel. 2) The crude ferric-oxide that is made by roasting the pickling liquor was dissolved in 20% HCI solution and then produced ferric chloride is purified by ethyl ether extraction. 3) The methanol solution of purified ferric chloride was sprayed into the refractory tube with compressed air and propane gas and then ignited leading to the ferric-oxide powder. 4) The produced oxide powder was introduced to the scrubber type vessel throught cooling system in order to collect the powder. 5) Crystalline phase of the powder was identified by X-ray diffraction and particle size, crystalline shape of the powder were investigated by settling method and electron microscope and the effects of concentration of ferric chloride in methanol on grain size were discussed. Results were obtained as fellows: 1) Total impurity in the ferric oxide produced from waste pickling liquor was 3.7%. 2) The solubilityof crude ferric oxide that was made from waste pickling liquor in HCI solution increased with the HCI concentration and reached to saturation range at 15% HCI concentration. 3) Extraction of FeCl3 increased with HCI concentration which is solvent. 4) Alpha ferric oxide obtained was very fine crystalline particles, the mean crystalline grain increased with the concentration of ferric chloride, and mean grain size distributed from 3.5$\mu$(at 0.5mole/l) to 0.5$\mu$(at 0.05mole/l).

  • PDF

The Martensitic Phase Transformation and Texture Development in Hadfield's Steels (Hadfield강에서의 마르텐사이트 상변태와 결정방위조직과의 관계 연구)

  • Kim, Taik-Nam
    • Korean Journal of Materials Research
    • /
    • v.5 no.7
    • /
    • pp.858-868
    • /
    • 1995
  • Texture development and martensitic phase transformation, on rolling, are compared in two Hadfield's steels, one having low carbon content(0.65wt% C), the other high carbon content(1.35wt%). In spite of small difference in stacking fault energy(about 2 mJm$^{-2}$ ) between two Hadfield's steels, the differences in texture development are observed. In low carbon steel, the textures developed are similar to those of low stacking fault energy metals in low strain range. However, the abnormal textures such as {111} , {110} <001> are strongly developed at high strain, which are due to the disturbance of u martensite in the development of textures formed at the packets of shear bands or at the grain boundaries. In contrast to low carbon Hadfield's steel( LCHS), the texture development of high carbon Hadfield's steel(HCHS) is simitar to those of low stacking fault energy metals in the whole strain range. This may be due to the fact that the amount of deformation induced martensite was small, as observed by A.C. magnetic susceptibility and iron particle tests.

  • PDF

Physicochemical Properties of Millet Starch Varieties (Millet 품종별 전분의 이화학적 성질)

  • Chung, Koo-Min
    • Korean Journal of Food Science and Technology
    • /
    • v.42 no.1
    • /
    • pp.115-118
    • /
    • 2010
  • The physicochemical properties such as blue value, iodine affinity, degree of polymerization (DP), $\alpha$-amylase digestibility, particle size, RVA pasting, and gel hardness of 4 different millet starches (foxtail, waxy foxtail, proso, and waxy proso) were investigated. The iodine affinity value of the four samples were 4.22, 0.49, 1.07, and 0.21%, and the DP values were 1830, 3880, 4660, and 4130, respectively. The levels of $\alpha$-amylase digestibility of the raw starches were 20.1, 30.7, 18.2 and 35.6%, respectively. The mean size of the proso millet starch was the smallest, $8.25\;{\mu}m$, and the size distribution of the particles was the narrowest among all the samples. Foxtail starch showed the largest peak viscosity and setback viscosity in RVA pasting.

Preparation of Asymmetric Ceramic Membrane by Coating-Pyrolysis Process (도포-열분해법을 이용한 비대칭 세라믹 분리막 제조)

  • Ryu, Hyun-Wook;Kim, Byung-Hoon
    • Journal of the Korean Ceramic Society
    • /
    • v.39 no.12
    • /
    • pp.1153-1157
    • /
    • 2002
  • The fabrication of a three-layered asymmetric ceramic membrane was performed by slip casting of the porous alumina support and dip coating of the alumina intermediate layer using high purity ${\alpha}-Al_2O_3$ powders that have different particle size, followed by screen printing-pyrolysis of the $Tio_2$ layer as an ultrafilteration membrane using Ti-naphthenate solution. The bending strength, porosity and mean pore size of the alumina support were 231 kg/$cm^2$s, 30.26% and 0.19 ${mu}m$, respectively. The thickness of the intermediate layer was 30 ${mu}m$ and the mean pore size of that was 0.063 ${mu}m$. Also, the top layer was 0.5 ${mu}m$ thick and micropores with about 20 nm size were formed uniformly.

Extraction Condition of Acidic Polysaccharide from Korean Red Ginseng Marc (홍삼박으로부터 산성다당체의 추출조건 조사)

  • Lee, Jong-Won;Do, Jae-Ho
    • Journal of Ginseng Research
    • /
    • v.26 no.4
    • /
    • pp.202-205
    • /
    • 2002
  • This study was carried out to investigate the optimum conditions for extraction of acidic polysaccharide from red ginseng marc produced by manufacturing alcoholic and water extract from red ginseng. Extraction efficacy of acidic polysaccharide from dried red ginseng marc was higher than that before drying. The appropriate conditions for the extraction of acidic polysaccharide from red ginseng marc were particle size under 3.35 mm after drying red ginseng marc, 1∼2 hours of extraction time and 2∼3 extraction times, respectively. The amount of acidic polysaccharide in water extract from red ginseng marc treated with $\alpha$-amylase and cellulase increased about 20∼50%. From the above resuts, we suggest that red ginseng marc produced by manufacturing alcoholic and water extract of red ginseng has higher potencies in the utilization of waste materials.

Synthesis of boehmite powder from aluminum etching solution (알루미늄 에칭액으로부터 베마이트 분말 합성)

  • Park, Young-Soo;Wui, In-Hee;Cho, Woo-Seok;Kim, Jin-Ho;Hwang, Kwang-Taek
    • Journal of the Korean Crystal Growth and Crystal Technology
    • /
    • v.22 no.6
    • /
    • pp.286-290
    • /
    • 2012
  • Boehmite (AlOOH) powder was synthesized using waste aluminium etching solution. In waste solution, precipitated phase was gibbsite ($Al(OH)_3$), and boehmite (AlOOH) phase was obtained at pH of 7 and 8 controlled by addition of acid. Boehmite powder was obtained by washing process to remove the Na ion in precipitated solution. Mean particle size of obtained powder was 40 nm. Boehmite phase transformed to ${\alpha}-Al_2O_3$ phase via ${\gamma}-Al_2O_3$, ${\delta}-Al_2O_3$, and ${\Theta}-Al_2O_3$.

Effect of the Powder Characteristics of Iron Oxides on the Magnetic Properties of Sr-ferrite (산화철의 분체특성이 Sr-ferrite의 자기특성에 미치는 영향)

  • 조태식;김효준;최승덕;남효덕;염충진
    • Resources Recycling
    • /
    • v.7 no.4
    • /
    • pp.43-49
    • /
    • 1998
  • We investigated the effects of the powder characteristics of various domestic iron oxides (${\alpha}Fe_2O_3$) on the magnetic properties of Sr-ferrites The particle size and the distribution of iron oxides were classified hy three different rerinning methods, and greatly a affected on the magn$\xi$tic prope$\pi$ies and the mmphology of Sr-ferntes. The agglomeration of Ruthner iron oxides and the large particles of Chemirite (CY) above $0.80{\mu}\textrm{m}$ were degraded the prope며es of Sr-fcrrites. The optimal magnetic prope$\pi$ies of Srt territes, showing 68.2 emu/g of saturation magnetization and 4300 Oe of intrinsic coerClvity, were achieved at the following c conditions; Chemirite (P2EP) iron oxides of $0.14{\mu}\textrm{m}$ molar ratio of 5.8. and calcination of $1150^{\circ}C$/1 hr.

  • PDF

Synthesis and Characteristic of ${\epsilon}$-type Copper Phthalocyanine Used as Color Filter in LCD Panel (입실론 프탈로시아닌의 합성 및 특성에 대한 연구)

  • Kim, Jae Hwan;Kim, Song Hyuk;Kim, Seong Jin;Hong, Seong-Soo;Lee, Gun-Dae;Park, Seong Soo
    • Applied Chemistry for Engineering
    • /
    • v.23 no.2
    • /
    • pp.138-142
    • /
    • 2012
  • The ${\epsilon}$ type copper phthalocyanine (${\epsilon}$-CuPc), called as a pigment blue 15 : 6, is a significant material to produce a blue pixel in LCD (Liquid Crystal Display) panel. In this study, ${\epsilon}$-CuPc sample was synthesized at various reaction conditions by applying the seed method using ${\epsilon}$-CuPc nanoparticles as a seed. Adequate synthetic conditions of the samples were selected by analyzing and comparing crystalline structure, crystalline purity, microstructure, and synthetic yield of the samples with ${\alpha}$ and ${\beta}$ crystalline CuPc samples. The chemical and crystalline structure of the samples were tested using FT-IR spectrometer and X-ray diffractometry, respectively. The shape of the particle was examined using field emission scanning electiron microscope while the thermal property was tested utilizing thermogravimetric analysis.

Dietary Exogenous α-Amylase Modulates the Nutrient Digestibility, Digestive Enzyme Activity, Growth-Related Gene Expression, and Diet Degradation Rate of Olive Flounder (Paralichthys olivaceus)

  • Md. Tawheed Hasan;Hyeon Jong Kim;Sang-Woo Hur;Seong-Mok Jeong;Kang-Woong Kim;Seunghan Lee
    • Journal of Microbiology and Biotechnology
    • /
    • v.33 no.10
    • /
    • pp.1390-1401
    • /
    • 2023
  • In this study, a 12-week feeding experiment was conducted to characterize the effects of exogenous α-amylase on the growth, feed utilization, digestibility, plasma α-amylase activity, feed degradation rate, and fecal particle size of olive flounder (Paralichthys olivaceus). Diet was supplemented with 0 (AA0; control), 100 (AA100), 200 (AA200), or 400 (AA400) mg/kg of α-amylase, respectively. Fish (273.1 ± 2.3 g) were stocked into 12 tanks (25 fish/1,000-L tank) and 3 tanks were randomly selected for each diet group. As a result, α-amylase was found to have no significant effects (p ≥ 0.05) on the growth, feed utilization parameters, and whole-body proximate compositions. α-Amylase-treated fish exhibited only a significant increase in the apparent digestibility coefficient of carbohydrates compared to the controls. In addition, in vitro analyses revealed that α-amylase dose-dependently increased (p < 0.05) the feed degradation rate, while photographs of the intestinal content after 2, 4, and 8 h of feeding demonstrated an improved degradation rate in the α-amylase-treated groups. Plasma α-amylase content was higher in the AA200 and AA400 groups, whereas the control group produced significantly larger-sized fecal particles (90% size class) than these two groups. In the intestine, no changes were observed in the expression levels of the immune-related TNF-α, IL-1β, IL-2, immunoglobulin-M, HSP-70, lysozyme, and amylase alpha-2A. However, growth-related genes IGF-1, IGF-2, TGF-β3, and growth hormone genes were upregulated in muscle tissues. Collectively, exogenous α-amylase has positive roles in the modulation of the digestibility coefficient, blood α-amylase concentration, growth-related gene expression, and diet degradation for improved digestion in olive flounder.

Contraction of Alpha-nickel Hydroxide Layers by Excess Coulombic Attraction of Anions (전기화학적으로 형성된 알파 상 니켈 수산화물의 층간 거리에 미치는 음이온의 영향 연구)

  • Kim, Gwang-Beom;Ganesh Kumar, V.;Bae, Sang-Won;Lee, Jae-Seong
    • Journal of the Korean Chemical Society
    • /
    • v.50 no.2
    • /
    • pp.141-152
    • /
    • 2006
  • In this study computer assisted instruction materials for the ‘Solution' chapter in high school chemistry II textbook were developed based on a view of particle and analyze the effect of the materials on 10th and 11th high school students. The contents of developed materials are dissolution, vapor pressure, the change of boiling point and freezing point, osmosis, and so on which are the major contents of Solution chapter in high school chemistry II textbook. Materials were developed with using animation and simulation for students understanding of the phenomena with a particle view point. Many phenomena in a solution were not simplified by colligative property of solution, but tried to explain by the concept of attraction between solute and solvent molecules. This computer assisted learning materials were developed using Flash 5.0 and Flash 6.0 Action Script. Educational effects of the materials on 10th and 11th grade students represented statistically meaningful increase of concept understanding. Especially the materials were effective to the transition stage or formal stage students in 10th grade and formal stage or the natural science major students in 11th grade.