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101.
Seong‐Ho Choi Min‐Seok Kim Jae Jeong Ryoo Kwang‐Pill Lee Hyun‐Dong Shin Sun‐Hwa Kim Yong‐Hyun Lee 《应用聚合物科学杂志》2002,85(11):2451-2457
Carboxylic acid groups were introduced onto polyethylene (PE) film by radiation‐induced graft copolymerization. Subsequently, the clodextrin glucanotransferase (CGTase) was immobilized on the PE film with a carboxylic acid group. The activity of the immobilized CGTase on PE film was in the range of 0.40–1.04 U/cm2 per min. The production of cyclodextrins (CDs) from corn starch was examined using the CGTase‐immobilized PE film. The production ratios of CDs using CGTase‐immobilized PE film was in the following order: α–CD > β–CD > γ–CD. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2451–2457, 2002 相似文献
102.
Do‐Hung Han Jae‐Hyuk Jang Hye‐Young Kim Byung‐Nam Kim Boo‐Young Shin 《Polymer Engineering and Science》2006,46(4):431-437
The high melt viscosity of polypropylene was studied by grafting bifunctional monomers, 1,6‐hexanediol diacrylate (HDDA) and tripropylene glycol diacrylate (TPGDA), onto homopolypropylene (HPP) and random ter‐polypropylene (RTPP) under electron‐beam irradiation. Creation of the high‐melt‐viscosity polypropylene was possible at low radiation dosage and low monomer content, under a prohibition of both radiation degradation and homopolymerization. TPGDA monomer was more effective in increasing the melt viscosity of HPP compared with RTPP, whereas HDDA monomer was more effective for enhancing the melt viscosity of RTPP. Such different effects of monomers on melt viscosity may arise from different monomer structures, namely, TPGDA has additional three methyl groups, but HDDA has no methyl groups. Electron‐beam radiation technology, on an increase of the melt viscosity, was much more effective in HPP than RTPP, when compared with virgin polymers. Modified RTPP and HPP with high melt viscosity were capable of foaming with numerous fine cells, of which the modified HPP with 1.5 mmol TPGDA and 0.5 kGy could create more spherical foam cells and its bending strength was 1.5 times more than that of the foamed RTPP. POLYM. ENG. SCI., 46:431–437, 2006. © 2006 Society of Plastics Engineers. 相似文献
103.
Sang-Gon Kim Jong-Sung Park Jae-Sul An Kug Sun Hong Hyunho Shin Hyungsun Kim 《Journal of the American Ceramic Society》2006,89(3):902-907
Various types of crystalline ceramic fillers (TiO2 , ZrO2 , Al2 O3 , MgO, and cordierite) were added to BaO–ZnO–B2 O3 –SiO2 (BZBS) glass (5–20 wt%), and the resultant dielectric constant, coefficient of thermal expansion (CTE), and optical reflectance were investigated for the application of the composites to the barrier ribs in plasma display panels. All the investigated fillers were partially dissolved into the glass at the fabrication temperature (575°C), and the residual fillers were aligned along the boundaries of sintered glass frits. By considering all aspects of the properties, the addition of TiO2 fillers of about 10 wt% to BZBS glass was the most desirable of the types of fillers investigated. The addition of TiO2 filler (10 wt%) yielded 61% in optical reflectance, 8.3 × 10−6 K–1 in coefficient of thermal expansion, and 15.5 in dielectric constant, which were properties comparable with the currently used Pb-based barrier ribs. 相似文献
104.
Kwang Ho Kim Soo Won Lee Dong Won Shin Chan Gyung Park 《Journal of the American Ceramic Society》1994,77(4):915-921
Antimony-doped tin oxide films were prepared on Corning glass substrate by chemical vapor deposition from a gas mixture of SnCl4 –SbCl5 –H2 O. The electrical conductivity and optical transmission of tin oxide films were studied with antimony doping. The film conductivity increased largely without losing optical transparency with a small addition of antimony. The increase of the conductivity was attributed mainly to more electrons donated by pentavalent Sb ions in the SnO2 lattice. Large additions of antimony, however, diminished the conductivity, optical transparency, and crystallinity of the film. The diminution was found to be caused by fine Sb2 O5 phases codeposited with SnO2 . 相似文献
105.
Composites of silicon carbide (SiC) with up to 30 vol% of dysprosia (Dy2 O3 ) were fabricated by hot pressing and hot isostatic pressing. The effects of Dy2 O3 dispersions on the microstructure and on selected mechanical properties of the composites were investigated. When 10-15 vol% of Dy2 O3 was dispersed in the SiC matrix, the fracture toughness increased by ∼40%, whereas the flexural strength was comparable to that of unreinforced SiC. The increased fracture toughness was due to crack deflection, in conjunction with crack-interface grain bridging, and was not related to a phase transformation of Dy2 O3 in the matrix. 相似文献
106.
In multi-radio multi-channel wireless mesh networks, engineering the network capacity requires a complex cross-layer design. In this paper, in order to make the complex problem implementable in a distributed manner, we make a decoupling approach that breaks down the entire design space into routing and initial channel assignment, and distributed congestion control and local channel reassignment. We propose a unified priced-based framework for distributed congestion control and localized channel-link assignment algorithms. We demonstrate the convergence of the proposed algorithms with respect to different fairness objectives (i.e., proportional fairness and max–min fairness) via simulation on both grid and random topologies. The proposed algorithms achieve faster convergence with less overhead in the control and forwarding plane than previous multi-path based algorithms. 相似文献
107.
John Case Sanjay Jain Yuh Shin Ong Pavel Semukhin Frank Stephan 《Journal of Computer and System Sciences》2014
Automatic classes are classes of languages for which a finite automaton can decide whether a given element is in a set given by its index. The present work studies the learnability of automatic families by automatic learners which, in each round, output a hypothesis and update a long-term memory, depending on the input datum, via an automatic function. Many variants of automatic learners are investigated: where the long-term memory is restricted to be the current hypothesis whenever this exists, cannot be of length larger than the length of the longest datum seen, or has to consist of a constant number of examples seen so far. Learnability is also studied with respect to queries which reveal information about past data or past computation history; the number of queries per round is bounded by a constant. 相似文献
108.
Jae-Keun Lee Hee-Soo Shin Chan-Jung Park Chang-Geon Lee Jung-Eun Lee Young-Whan Kim 《Korean Journal of Chemical Engineering》2002,19(1):41-45
A laboratory-scale electrodewatering system, incorporating an electric field as an additional driving force to conventional
pressure dewatering, has been developed to decrease the water content of sludges generated in wastewater treatment. Consisting
of a piston-type filter press, a power supply and a data acquisition system, the electrodewatering system’s performance was
evaluated as a function of applied pressure, applied voltage, sludge type and filtration time. Experiments were carried out
using sewage sludges with the electric field up to 120 V/cm and pressure ranging from 98.1 to 392.4 kPa. Electrodewatering
involving a combination of electric field and pressure enhances both the dewatering rate and final dewatered volume. The final
water content of sewage sludges in the electrodewatering system can be reduced to 62 wt%, as compared to 78 wt% achieved with
the pressure filtration alone. The electrodewatering system shows the potential to be an effective method for reducing the
water content in sludges. 相似文献
109.
Dynamic mechanical properties of three different styrene-based ionomer blends containing ca. 5 mol% of ionic repeat units were investigated; the three ionic units were itaconate (ITANa), methacrylate (MANa), and styrenesulfonate (SNa). For SNa-MANa ionomers, it was observed that this ionomer system showed only two loss tangent peaks, implying that this ionomer system resembles a typical miscible system. When the ion content increased, however, the ionomer blend showed two cluster loss tangent peaks, indicating the presence of phase-separated cluster regions. This suggests that, with increasing ion content, the role of ionic units becomes more important than that of host non-ionic units to determine ionomer properties. In the case of ITANa-MANa and ITANa-SNa ionomers, however, it was suggested that the multiplets of the MANa and SNa ionomers might be disrupted upon the addition of the ITANa ionomers. In addition, the SEM images showed that the fracture surfaces of ionomers changed upon blending. 相似文献
110.
Ki-Pung Yoo Hun Yong Shin Min Jeong Noh Seong Sik You 《Korean Journal of Chemical Engineering》1997,14(5):341-346
To design a supercritical fluid extraction process for the separation of bioactive substances from natural products, a quantitative
knowledge of phase equilibria between target biosolutes and solvent is necessary. How-ever, mostly no such information is
available in literature to date. Thus in the present study, illustratively the solubility of bioactive coumarin and its various
derivatives (i.e., hydroxy-, methyl-, and methoxy-derivatives) in supercritical CO2 were measured at 308.15–328.15 K and 10–30 MPa. Also, the pure physical properties such as normal boiling point, critical
constants, acentric factor, molar volume and standard vapor pressure for coumarin and its derivatives were estimated. By these
estimated information, the measured solubilities were quantitatively correlated by an approximate lattice equation of state
proposed recently by the present authors. 相似文献