MATERIALS SCIENCE FORUM
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2020
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IF 0
Hong Qian Dai,Yuan Lu,Zhi Hin Ou,Min Xu
Fe3O4-APTES-CS2 was prepared by modification of Fe3O4 with 3-aminopropyltriethoxysilane (APTES) and carbon disulfide (CS2). Lipase was covalently bonded to Fe3O4-APTES-CS2 to obtain the immobilized lipase Fe3O4-APTES-CS2-lipase. The textural characteristic of Fe3O4-APTES-CS2-lipase was assessed by scanning electron microscopy. The optimal immobilization conditions were 2.5 mg/mL lipase, pH 7.0, 35 °C, 3 h. The loading amount of lipase was 119.0 mg/g carrier. The immobilization efficiency reached 57%. (R)-(+)-N-acetyl-1-methyl-3-amphetamine was synthesized by Fe3O4-APTES-CS2-Li- pase. The conversion, enantiomeric excess of (R)-(+)-N-acetyl-1-methyl-3-amphet-a- mine and E value reached 36.8%, 98.5% and 132, respectivel.
研究领域:
化学
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生物化学
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材料科学
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催化
✓ 已验证
DOI
MATERIALS SCIENCE FORUM
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2020
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IF 0
Meng Lei Zhou,Li Na Zhang,Yang Liu,Feng Qiang Nan
In order to obtain better quality and mechanical performances, the coating process of super-porous propellants was optimized. The mechanical performances of super-porous propellants were tested, under some conditions with different temperatures, different numbers of cladding layers, different thicknesses of the cladding layer and different ratios of inner and outer layers, through many different analytical methods including impact test, interrupted-burning test and three-dimensional video observation test. The results show that the mechanical performances of super-porous propellants are positively correlated with the temperature, the coating thickness and the ratio of the outer layer. The double-layer coating also can obtain better coating effect than the single-layer coating.
研究领域:
材料科学
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航空航天工程
✓ 已验证
DOI
MATERIALS SCIENCE FORUM
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2019
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IF 0
Rong Hua Zhuang,Jian Ying Yu,Heng Chang,Yan Zeng,Xue Yong Lan
The effects of modified natural zeolite warm mix agent (MNZWMA) and organic viscosity reducing warm mix agent (OVRWMA) on the physical properties, short term thermal oxidation aging, long term thermal oxidation aging and UV aging properties of the crumb rubber modified bitumen (CRMB) were investigated. The results showed that MNZWMA and OVRWMA could improve the high temperature stability and the low temperature crack resistance of CRMB, respectively. During the short term thermal oxidation aging, long term thermal oxidation aging and UV aging, OVRWMA increased softening point increment (SPI) and viscosity aging index (VAI) of CRMB, however, MNZWMA decreased its SPI and VAI. The analysis of FTIR spectra indicated that MNZWMA reduced the formation of carbonyl groups and sulfoxide groups, but OVRWMA accelerated the formation of carbonyl groups and sulfoxide groups to some extent during ultraviolet aging. Therefore, MNZWMA could improve the anti-aging properties, and OVRWMA was not conducive to the anti-aging properties of CRMB.
研究领域:
土木工程
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材料科学
✓ 已验证
DOI
MATERIALS SCIENCE FORUM
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2015
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IF 0
Wei Xing Chen,Ping Chui,Ai Jie Ma,Chun Yan Luo,Yong Qian Gu,Qiao Yan Mi
Two kinds of Schiff bases polymers named P3TA4A and P3TA4B were prepared by the chemical oxidation method. The structures of Schiff bases polymers were determined by FT-IR and 1H NMR. The GPC result showed that the number-average molecular weight of P3TA4A and P3TA4B was 7400 g/mol and 12500 g/mol with a molecular weight distribution of 1.63 and 1.27, respectively. The cyclic voltammetry curves showed that the energy gap of P3TA4A and P3TA4B was 1.929 eV and 1.944 eV, respectively. Ultraviolet-visible spectra and Luminescence spectra showed that the maximum absorption and maximum emission wavelength of was 275 nm, 400 nm for P3TA4A and 448 nm, 451 nm for P3TA4B. The open-circuit voltage of the polymer solar devices was 3 mv and 2.5 mv, respectively. The results indicated that the Schiff bases substituents at the 3-position of polythiophenes play an important role on the photoelectric conversion efficiency of conducting polymers.
研究领域:
材料科学
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能源科学
✓ 已验证
DOI
MATERIALS SCIENCE FORUM
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2018
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IF 0
Qin Yu Pei,Rui Wang,Xue Qin Jin,Guo Jing Gou
In this paper, we synthesized a CdHgTe type water-soluble quantum dots, combined in the next time with the drug delivery system "dextran - magnetic layered double hydroxide - fluorouracil" (DMF), built a new nanostructures platform QD@DMF for blending the fluorescent probe function of quantum dot together with the magnetic targeting curative effect of the DMF system. The Fluorescence spectrophotometer, Ultraviolet spectrophotometer, TEM and XRD were used to characterize the luminescent properties, particle morphology and phase characteristics of the QD@DMF samples. The experiments on cell imaging were carried out by laser con-focal scan microscopy technique. Results showed that the CdHgTe QDs could be successfully grafted onto the surface of the DMF system through electrostatic coupling, forming a special structure based on magnetic layered double hydroxide with a near-infrared emission wavelength in 575~780 nm. Compared with QDs, the QD@DMF composite could significantly improve the cell imaging effect, the label intensity increased with the magnetic field intensity and obeyed the linear relationship Dmean = 1.760+0.013B. The fluorescent magnetic nanoparticles maintained not only the super-paramagnetic of DMF but also the photoluminescence properties of the QDs, implicating that the QD@DMF composite may be an effective multifunction tool for optical bio-imaging and magnetic targeted therapy.
✓ 已验证
DOI
MATERIALS SCIENCE FORUM
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2014
·
IF 0
Fang Wei Qi,Xue Gang Luo,Xiao Yan Lin
In present study, two kinds of CaCO3 with micro-sized and nanometer-sized particles were treated by pimelic acid (PA) with different proportion. Then the treated particles (the total content of micro-sized and nanometer-sized CaCO3 particles was 10 wt%) were mixed with polypropylene (PP) to prepare CaCO3/PP composites by melting blending. The crystallization behavior and morphology of composites were studied by wide-angle-X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and polarized microscope (PLM), respectively. Compared with PP and other samples, the content of β-crystal in the composite NCP2 where the ratio of nanoand micro particles was 2:8 (NCP2), reached the highest values. The growth speed of crystals in PP matrix was much quicker, leading to the larger spherulites than the NCP2 and NCP8. The time of complete nucleation for NCP8 was lower than PP, but higher than NCP2.
研究领域:
材料科学
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高分子科学
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复合材料
✓ 已验证
DOI
MATERIALS SCIENCE FORUM
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2015
·
IF 0
Wei Cai,Chun Lin Fu,Rong Li Gao,Wei Hai Jiang,Xiao Ling Deng,Gang Chen
Bismuth ferrite is an important material in ferroelectric photovoltaic field, because of its narrow band gap and large polarization. Doping is a common method to further improve the photovoltaic properties of bismuth ferrite. Mn-doped bismuth ferrite thin films were prepared by sol-gel method. The effects of manganese on the crystal structure, ferroelectric and photovoltaic properties have been investigated. The result indicates that Mn-doped bismuth ferrite thin films are single phase and the lattice constant increases with the increase of manganese content. As manganese content increases, the remnant polarization and coercive electric field increase, while the short circuit photocurrent density and power conversion efficiency decrease. The open circuit photovoltage increases first and reaches the maximum and then decreases as manganese content increases. The results indicate that enhanced ferroelectricity caused by addition of manganese doesn’t make improvement on the photovoltaic characteristic.
研究领域:
材料科学
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物理学
✓ 已验证
DOI
MATERIALS SCIENCE FORUM
·
2016
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IF 0
Jia Xing Jiang,Li Mei Li,Li Li Lin,Yi Zuo,Yu Bao Li,Ji Dong Li
To well understand the influence of the sterilization on the properties of biomaterials prior to application is pivotal. The effect of γ-ray irradiation on the mechanical and thermal properties of nanohydroxyapatite/polyurethane (n-HA/PU) porous scaffold for bone tissue engineering was studied in this paper. The mechanical testing, fourier transform infrared spectroscopy and thermal analysis were employed to determine the structure and properties change of these composite scaffolds after γ-ray irradiation with different doses.The results show that thermal stability, and mechanical properties of the composite scaffolds increase after γ-ray irradiation with doses of15 kGy to 25 kGy, especially the irradiation dose of 15kGy which imposed a remarkable effect on these properties. However, a reverse trend is found when the 50kGy irradiation dose was applied.In general, it can be concluded that sterilization using γ-ray irradiation with proper dose has no adverse effect on the properties of n-HA/PU composite scaffolds.
研究领域:
生物材料学
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医学工程
✓ 已验证
DOI
MATERIALS SCIENCE FORUM
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2015
·
IF 0
Wei Xing Chen,Yong Qiang Gu,Chun Yan Luo,Xiao Long Zhang
Three kinds of poly (3-alkylthiophene), such as poly (3-butylthiophene) (P3BT), poly (3-hexylthiophene) (P3HT) and poly (3-dodecylthiophene) (P3DDT) were prepared by the Grignard Metathesis Method (GRIM). Their chemical structures are characterized by FTIR, 1H-NMR and GPC. 1H-NMR result shows that regioregular structure of these polymers is relatively higher. The GPC results show that the molecular weight of the polymers is 8.42×104, 1.06×105 and 1.21×104 g/mol with molecular weight distributions of 1.41, 2.18 and 1.18, respectively. The DSC result shows that the glass transition temperature of three kinds of polymers is 120.8, 146, 118 °C, respectively. UV absorption spectrum and fluorescence spectroscopy of three polymers in THF solution show that the maximum absorption wavelength is 448 nm, 470 nm, 390 nm, and the maximum emission wavelength is 531, 535, 527 nm with the band gap of 2.06, 1.86, 2.21 eV, respectively.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
MATERIALS SCIENCE FORUM
·
2021
·
IF 0
Jia Li,Shuai Lin,Yue Long Ma,Xian Hua Xu,Wei Zheng,Li Bo Li
The coaxial electrospun fibers with large specific surface area, high porosity and core-shell structure have been great applied in biomedical field, especially as drug delivery carriers. In this paper, PLGA(polylactic acid/glycolic acid copolymer) was used as the core and the mixture of PLGA and gelatin was used as the shell. PLGA/gelatin fiber was prepared by coaxial electrospinning technology. The effects of different parameters on the surface morphology and the diameter of fibers were investigated.
研究领域:
生物材料学
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医学工程
✓ 已验证
DOI
MATERIALS SCIENCE FORUM
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2020
·
IF 0
Zheng Li,Zi Jian He,Ying Cheng Zhou,Yi Tang,Yu Fang Chen,Tao Jin
In this paper, Dimethyl sulfoxide (DMSO) was used in the activating process of cotton filter cloth to improve its further hydrophobic modification reaction between cotton fabric and 1-octadecene via an electron transfer (ARGET) atom transfer radical polymerization (ATRP) mechanism. The major influences of DMSO on ARGET-ATRP process was discussed, and meanwhile, the microstructure changes, morphology feature and performance characteristics of cotton filter cloth during the reaction was explored by the SEM, AFM, EDS, XRD and TGA techniques.The result shows that DMSO can leads to cotton fibers adhesion and surface roughening under the ARGET-ATRP grafting reaction conditions, but has little changes on the crystal form, crystallinity and thermal properties of cellulose. At a DMSO dosage of 10%, the hydrophobically modified cotton filter cloth has a water contact angle (CA) of up to 141°. While naturally placed for 1 hour, the CA of hydrophobically modified cotton filter cloth can be stable at 116° with a decay rate of 17.5%, which proves that the hydrophobic stability of cotton filter cloth has been improved markedly. Furthermore, a better improvement for the hydrophobic stability of cotton filter cloth will significantly enhance the application of hydrophobic functional modified cellulosic materials.
研究领域:
材料科学
·
纺织工程
✓ 已验证
DOI
MATERIALS SCIENCE FORUM
·
2020
·
IF 0
Min Gao
The jute and polypropylene fiber (PP) were formed into jute/PP composite by carding, netting and needling. Using surface dusting process, β-CD and ammonium phosphate (APP) were combined and hot pressed to form a flame-retardant layer on the surface of jute/PP composite. The results show that the thermal compression film formation on the surface of jute/PP composite after β-CD and APP compounding can significantly improve the flame retardancy and thermal stability of the jute/PP composite. When the mass ratio of β-CD to APP is 1:2 and keeping the 20wt% total content of the flame retardants, the jute/PP composite becomes extinguished after 58s combustion. The limiting oxygen index (LOI) value is 26.6%, which reaches the third fire resistance according to Japan's JISD 1201-77 standard. The heat release rate and effective combustion calorific show the lowest value and the carbon residual at 700°C is increased by 11. 68%.
研究领域:
材料科学
·
燃烧学
✓ 已验证
DOI
危险品化学品经营许可证（带存储）