• Title, Summary, Keyword: fiber type composition

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Polymer Electrolytes Based on Poly(vinylidenefluoride-hexafluoropropylene) and Cyanoresin

  • Lee, Won-Jun;Kim, Seong-Hun
    • Macromolecular research
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    • v.16 no.3
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    • pp.247-252
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    • 2008
  • Lithium gel electrolytes based on a mixed polymer matrix consisting of poly(vinylidenefluoride-hexafluoropropylene) (PVDF-HFP) and cyanoresin type M (CRM) were prepared using an in situ blending process. The CRM used in this study was a copolymer of cyanoethyl pullulan and cyanoethyl poly(vinyl alcohol) (PVA) with a mole ratio of 1:1. The mixed plasticizer was ethylene carbonate (EC) and propylene carbonate (PC) with a volume ratio of 1:1. In this study, the presence of PVDF in the electrolytes helps to form a dimensionally stable film over a broad composition range, and decreases the viscosity. In addition, it provides better rheological properties that are suitable for the extrusion of thin films. However, the presence of HFP has a positive effect on generating an amorphous domain in a crystalline PVDF structure. The ionic conductivity of the polymer electrolytes was investigated in the range 298-333 K. The introduction of CRM into the PVDF-HFP/$LiPF_6$, complex produced a PVDF-HFP/CRM/$LiPF_6$ complex with a higher ionic conductivity and improved thermal stability and dynamic mechanical properties than a simple PVDF-HFP/$LiPF_6$, complex.

Synthesis and Properties of A-B-A Type Block Copoly(ester-ether) Comprising Poly(L-lactic acid) (A) and Poly(oxyethylene) (B) (Poly(L-lactic acid)와 Poly(oxyethylene)의 A-B-A 블록공중합체 합성과 그 특성)

  • 이찬우
    • Textile Science and Engineering
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    • v.34 no.3
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    • pp.143-147
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    • 1997
  • An A-B-A block copoly (ester-ether) comprising poly(L-lactic acid) (A) and poly (oxyethylene) (B) was prepared by copolymerization of L-lactide and a commercially available telechelic polymer, polyethylene glycol (PEG), with different molecular weights by the catalysis of triethyl aluminium/toluene. The molecular weight and the unit composition were successfully controlled by changing the L-lactide/PEG ratio in feed. DSC curves of the copolymers are ascribed to the endothermic peak with PEG segment and exothermic peak by PLLA segment. There is a tendency that melting temperature ($T_m$) reduced with increasing PEG composition. These results suggested that the PEG segments and PLLA are compatible and homogeneously mixed in the amorphous phase of PLLA without forming a microphase separation in the solid state. The compatibility of both polymers, however, would not be so high as to prevent crystallization of PLLA. It was found that the copolymer films showed an improved flexibility due to the incorporation of the soft PEG segment. The in vitro hydrolysis test of the films showed that the block copolymer has much higher degradability than the homo poly(L-lactic acid)

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REPULSIVE EFFECT AND PALATABILITY OF DIETARY PHENYLALANINE IN LAYING HENS

  • Choi, Y.-H.;Asakura, K.;Okumura, J.;Furuse, M.
    • Asian-Australasian Journal of Animal Sciences
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    • v.9 no.2
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    • pp.159-164
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    • 1996
  • Food intake of birds can be affected by particle size as well as diet composition, In order to investigate whether food intake of diets including excessive amount of phenyalanine(Phe) was influenced by diet types. a series of experiments were conducted in growing chicks and laying hens. Growing chicks significantly decreased food intake in a semipurified excessive Phe diet compared with a semipurified control diet, while laying hens fed a practical diet including excess Phe did not significantly reduce their food intake over a corn starch-substituted control diet. In an attempt to find out whether diet type affects food intake in layers, the semipurified type diet with excess Phe greatly reduced food ingestion, but the effect was delayed in the practical type diet. Moreover, under choice feeding regimes between the Phe and either starch, tyrosine(Tyr) or fiber diets in order to investigate whether the decreased food intake in the presence of an excess of dieary Phe in laying hens is involved in the palatability for the diet, there was no significant difference between Phe and starch diet while a preference for the Phe diet tended to be increased when birds were offered Tyr. Laying hens ingested significantly more the Phe diet than the fiber diet within 1 h after feeding. For supporting the idea that preference for the Phe diet may be affected by manipulating taste sense, an anaesthetic or saline was intramuscularly administered under the tongue just before a choice feeding. Preference for the Phe diet was not significantly different from that for the fiber reference diet within 1 h in the anaesthetized birds while the birds preferred the Phe diet in the saline treated group. It is suggested that because birds are able to select a diet, the decreased food intake induced by dietary excess Phe may be due to the repulsive effect of Phe after ingestion but not the taste of Phe.

The Changes of Molecular Weight and Structure in the Preparation Process of Silk Fibroin Powder (견 피브로인의 분말화에 의한 분자량 및 구조변화)

  • 김동건;김용학;김규범;진영길
    • Textile Science and Engineering
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    • v.38 no.3
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    • pp.105-110
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    • 2001
  • A study was undertaken to obtain useful fibroin powder from the silk wastes. For the preparation of silk fibroin powder, neither salts nor acids were used as solvents, but the wastes were solved in water under the high temperatures and dried to gain very high concentrated silk powder. Then the powder was further decomposd with proteolytic enzymes. The characteristics were identifed by means of the solubility, DSC, GPC, and XRD. The composition of the silk powder was confirmed by the amino acid analyzer. It was found that the endothermic peak wasreduced as the increase of decomposing temperatures and hours at about 33$0^{\circ}C$, the molecular weight distribution showed a reducing tendency, the second decompositions were less molecularized by 20% than the first ones, the average molecular weight of 4,700 was shown in the second treatments, the X-ray diffraction showed the crystalline structure transformation between second treatments, the X-ray diffraction showed the crystalline structure transformation between silk I and II types, and the composition of amino acids was nearly identical regardless of decomposition methods and conditions.

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Effect of Additives and Fermentation Periods on Chemical Composition and In situ Digestion Kinetics of Mott Grass (Pennisetum purpureum) Silage

  • Nisa, Mahr-un;Touqir, N.A.;Sarwar, M.;Khan, M. Ajmal;Akhtar, Mumtaz
    • Asian-Australasian Journal of Animal Sciences
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    • v.18 no.6
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    • pp.812-815
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    • 2005
  • This study was conducted to see the influence of additives and fermentation periods on Mott grass silage (MGS) characteristics, its chemical composition and to compare the digestion kinetics of Mott grass (MG) and MGS in Nili buffaloes. Mott grass chopped with a locally manufactured chopper was ensiled using two additives, cane molasses and crushed corn grains each at 2, 4 and 6% of forage DM for 30 and 40 days in laboratory silos. The pH, lactic acid concentration, dry matter (DM), crude protein and fiber fractions of MGS were not affected by the type or level of additive and fermentation periods. The non-significant pH lactic acid concentration, and chemical composition of MGS indicated that the both molasses and crushed corn were utilized at similar rate for the growth of lactic acid bacteria and production of organic acids. The MG ensiled with molasses at 2% of fodder DM for 30 days was screened out for in situ digestion kinetics in Nili buffaloes. Ruminal DM and neutral detergent fiber (NDF) degradabilities of MGS were significantly (p<0.05) higher than that of MG. The DM and NDF rate of degradation, lag time and extent of degradation was nonsignificant between MGS and MG. The higher ruminal degradation of DM and NDF of MGS than MG was probably a reflection of fermentation of MG during ensilation that improved its degradability by improving the availability of easily degradable structural polysaccharides to ruminal microbial population. The results in the present study have indicated that MG ensiled with either 2% molasses or 2% crushed corn for 30 days has better nutritive value for buffalo.

The Study on Physical Properties and Applicability of Material of Polyamide-66/Glass Fiber Blends Composition to the Eyewear Frame (Polyamide-66/Glass fiber 블렌드 조성물의 물리적 특성 및 안경테 소재로써의 적용성에 관한 연구)

  • Son, Jin-Young;Lee, Ji-Eun;Choi, Kyung-Man;Bae, Yu-Hwan;Kim, Ki-Hong
    • Journal of Korean Ophthalmic Optics Society
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    • v.18 no.4
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    • pp.365-371
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    • 2013
  • Purpose: In this study, we evaluated the physical and thermal properties of the compositions made by blending glass fiber (GF) of different contents into glass fiber polyamide-66, and investigated if the compositions applying to the glasses frame to replace the TR-90, which is polyamide-12 resin used as an injection-type spectacle frame material. Methods: To investigate the characteristics change of polyamide-66 (PA-66) compositions with the change of the content of glass fibers, we produced a composition of the content by using a twin-screw extruder. The mechanical strength of the composition production was measured and coating properties as well as cutting processability were evaluated. We evaluated the applicability of the glasses frame by comparison the results of new compositions with characterizations of traditional TR. Results: For the results of the characterization of Polyamide-66/GF composition, we found that the higher increase of content of the glass fiber, the less mold shrinkage rate, and the mechanical strength was increased. Tensile strength increased from $498kg/cm^2$ for 0 wt% of the content of the glass fibers to $849kg/cm^2$ for 30 wt% of the content of the glass fibers. As a result of a coating evaluation, the strength of coating was 4B in the GF 5wt% and 5B, which was extremely good coating characteristics, in the over than GF 5 wt%. Conclusions: In case that 30 wt% of the glass fiber was blended, the mechanical strength was greatly improved, the hardness was increased, injection temperature increased due to increase of the viscosity, and the flow mark of the product may occur. The paint coating of PA-66 blended with glass fiber was all excellent. With general evaluating physical properties and workability properties it was determined that around 10 wt% of the content of the glass fibers was possible to apply a spectacle frame.

Potassium loading effects for activated carbon fiber pre-treated with phosphoric acid (인산을 전처리한 활성탄소섬유에 칼륨 처리효과)

  • Oh, Won-Chun;Bae, Jang-Soon
    • Analytical Science and Technology
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    • v.18 no.4
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    • pp.355-361
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    • 2005
  • The objective of this paper is to compare the surface features of two kinds of activated caron fiber (ACF) treated with potassium and the variation of their properties by phosphoric acid pre-treatment. X-ray diffraction (XRD) patterns indicate that activated carbon fiber containing potassium species show better performance for metal and metal salts by pre-treatment with phosphoric acid. In order to present the causes of the differences in surface properties and specific surface area after the samples were treated with phosphoric acid, pore structure and surface morphology were investigated by adsorption analysis and SEM. For the chemical composition microanalysis for potassium leading of the activated carbon fibers pre-treated with phosphoric acid, samples were analyzed by EDX. Finally, the type and quality of oxygen groups were determined from the method proposed by Boehm.

Adsorption Characteristics of PES-BSA Affinity Membrane Prepared by Electrospinning (전기방사로 제조된 PES-BSA 친화막의 흡착특성)

  • Byun, Hong-Sik;Hong, Byung-Pyo
    • Membrane Journal
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    • v.18 no.4
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    • pp.306-316
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    • 2008
  • The adsorption characteristics of L-tryptophan of PES-BSA affinity membranes prepared by using electro-spinning were investigated. It was found that the fiber diameters could be controlled by the comparisons of fiber diameters prepared by various spinning conditions through FESEM and Image Analyzer. Darcy's permeability constants, mechanical properties and hydrophobic properties were enhanced since micro-fibers increased by increasing the composition ratio of HFB and BSA. The elution capacity of L-tryptophan in borate-DMSO buffer solution was higher than that in tris-HCl buffer solution, while the elution capacity of A 7906 type BSA was higher than A 8022 type BSA. This is due to the characteristics of BSA type, i. e. higher purity and uniform molecular weight and better pH stability of A 7906 type BSA than those of A 8022 type BSA.

Effects of SiC Particle Size and Inorganic Binder on Heat Insulation of Fumed Silica-based Heat Insulation Plates

  • Jo, Hye Youn;Oh, Su Jung;Kim, Mi Na;Lim, Hyung Mi;Lee, Seung-Ho
    • Journal of the Korean Ceramic Society
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    • v.53 no.4
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    • pp.386-392
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    • 2016
  • Heat insulation plates of fumed silica were prepared by mixing fumed silica, SiC powder and chopped glass fiber by a high speed mixer followed by pressing of the mixture powder in a stainless steel mold of $100{\times}100mm$. Composition of the plates, particle size of SiC, and type of inorganic binder were varied for observation of their contribution to heat insulation of the plate. The plate was installed on the upper portion of an electric furnace the inside temperature of which was maintained at $400^{\circ}C$ and $600^{\circ}C$, for investigation of heat transfer through the plate from inside of the electric furnace to outside atmosphere. Surface temperatures were measured in real time using a thermographic camera. The particle size of SiC was varied in the range of $1.3{\sim}17.5{\mu}m$ and the insulation was found to be most excellent when SiC of $2.2{\mu}m$ was incorporated. When the size of SiC was smaller or larger than $2.2{\mu}m$, the heat insulation effect was decreased. Inorganic binders of alkali silicate and phosphate were tested and the phosphate was found to maintain the heat insulation property while increasing mechanical properties.

Preparation of the Hollow Fiber Type Perovskite Catalyst for Methane Complete Oxidation (메탄의 완전산화 반응을 위한 중공사형 페롭스카이트 촉매 제조)

  • Lee, Seong Woon;Kim, Eun Ju;Lee, Hong Joo;Park, Jung Hoon
    • Korean Chemical Engineering Research
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    • v.56 no.3
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    • pp.297-302
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    • 2018
  • Bead type and hollow fiber type catalyst (HFC, Hollow Fiber type Catalyst) was prepared by $La_{0.1}Sr_{0.9}Co_{0.2}Fe_{0.8}O_{3-{\delta}}$ (LSCF1928) perovskite powder catalyst which showed excellent methane complete oxidation characteristics through previous studies. The HFC have a cylindrical shape with an empty interior, and pores can be formed through Phase inversion method so the specific surface area can be remarkably improved. In the case of the bead type catalyst prepared by adding Methyl Cellulose (MC), $SrCO_3$ was produced in addition to the original catalyst composition of LSCF1928 due to the reaction of $CO_2$ emitted from MC and Sr of the catalyst. In the case of the HFC, a single phase perovskite structure was obtained without impurities. The HFC calcined at $700{\sim}900^{\circ}C$ showed pore structure of finger-sponge-finger structure, and 99.9% oxygen conversion rate was achieved through complete oxidation of methane at $475^{\circ}C$. Air gap and spinning pressure condition were changed to control the HFC pore. 2 cm air gap and 7 bar spinning pressure showed the best catalytic performance and achieved oxygen conversion rates of more than 70.65%, 93.01%, and 99.99% at $425^{\circ}C$, $450^{\circ}C$ and $475^{\circ}C$, respectively.