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991.
The study addressed starch-based coatings on paper and fabrics. Coated materials and free starch films containing different
amounts of a well-established plasticizer (glycerol) or potential plasticizer (mainly polyols) were tested with respect to
water vapour permeance (WVPe), water vapour permeability (WVP), glass transition temperature (Tg), and mechanical strength (tensile tests). Both normal and high- amylose potato starch were used. These starches were modified
by (a) oxidation, (b) oxidation and hydroxypropylation or (c) oxidation and hydrophobically modified by reaction with octenyl-
or alkenyl-substituted succinic acid anhydride. Free films of hydroxypropylated high-amylose potato starch showed a lower
WVP than did the corresponding starches based on regular potato starch. The WVP of the hydrophobically modified regular potato
starches was substantially higher than that of films of the corresponding hydroxypropylated starches. The expected hydrophobic
effect of the succinic acid anhydrides in terms of a reduced WVP could not be observed. When glycerol was used as a plasticizer,
about 30 parts (by wt.) per hundred parts of starch were needed in order to reduce the Tg and to cause observable changes in the mechanical properties of the free films. 相似文献
992.
Humidity Effect on Toluene Decomposition in a Wire-plate Dielectric Barrier Discharge Reactor 总被引:1,自引:0,他引:1
Guo Yu-fang Ye Dai-qi Tian Ya-feng Chen Ke-fu 《Plasma Chemistry and Plasma Processing》2006,26(3):237-249
Laboratory-scale experiments were performed to evaluate the humidity effect on toluene decomposition by using a wire-plate dielectric barrier discharge (DBD) reactor at room temperature and atmospheric pressure. The toluene decomposition efficiency as well as the carbon dioxide selectivity with/without water in a gas stream of N2 with 5% O2 was investigated. Under the optimal humidity of 0.2% the characteristics of toluene decomposition in various background gas, including air, N2 with 500 ppm O2, and N2 with 5% O2 were observed. In addition, the influence of a catalyst on the decomposition was studied at selected humidities. It was found that the optimum toluene removal efficiency was achieved by the gas stream containing 0.2% H2O, since the presence of water enhanced the CO2 selectivity. In addition, the toluene removal efficiency increased significantly in a dry gas stream but decreased with an increase in the humidity when the Co3O4/Al2O3/nickel foam catalyst was introduced into the discharge area. 相似文献
993.
合成了反式-1,2-双[5-(2,4,6-三甲基苯基)(口恶)唑-2-基]乙烯(1_a),并用分子力学法(MMX程序)计算了标题化合物(POEOP,2,5-二甲基-POEOP及2,4,6-三甲基POEOP).POEOP的结构、构象与X衍射结果颇吻合,分子中2个(口恶)唑环呈稳定的反向排布.比同向排布稳定4.6kJ/mol,旋转能垒约16.8~20.9 kJ/mol.还讨论了标题系列化合物的构象对其紫外光谱的影响. 相似文献
994.
Shinsuke Yamanaka Hiroaki Muta Shin-ichi Kobayashi 《Journal of solid state chemistry》2004,177(10):3484-3489
Polycrystalline samples of strontium series perovskite type oxides, SrHfO3 and SrRuO3 were prepared and the thermophysical properties were measured. The average linear thermal expansion coefficients are 1.13×10−5 K−1 for SrHfO3 and 1.03×10−5 K−1 for SrRuO3 in the temperature range between 423 and 1073 K. The melting temperatures Tm of SrHfO3 and SrRuO3 are 3200 and 2575 K, respectively. The longitudinal and shear sound velocities were measured by an ultrasonic pulse-echo method at room temperature in air, which enables to evaluate the elastic moduli and Debye temperature. The heat capacity was measured by using a differential scanning calorimeter, DSC in high-purity argon atmosphere. The thermal diffusivity was measured by a laser flash method in vacuum. The thermal conductivities of SrHfO3 and SrRuO3 at room temperature are 5.20 and 5.97 W m−1 K−1, respectively. 相似文献
995.
It is a theoretical study on the water-assisted mechanism of one-carbon unit transfer reaction, in which the energy barrier for each transition state lowered by about 80-100 kJ/mol when compared with the one in no-water-involved mechanism. The water-assisted path 4 is the favorite reaction way. Our results well explained the presumption from experiments. 相似文献
996.
分别将3-磺酸丙基、磷酸基和4—N一苯基三甲基碘化铵基引进乙烯-乙烯醇共聚物(EVA)链中制得了聚阳离子和聚阴离子,然后得到相应的聚离子复合物.当EVA分子链中的羟基的取代度在60%以上时,所制得的中性聚离子复合物的血浆凝固时间和空白玻璃的血浆凝固时间之比可在8~13之间,而负电性聚离子复合物可高达110左右.这些聚离子复合物膜对小分子电解质或小分子中性物质如氯化钠、尿素、葡萄糖等表观渗透系数皆在10-7cm2\s以上. 相似文献
997.
制备了一种新的基因载体材料———赖氨酸修饰的壳聚糖(CTS-lys)包裹的磁性纳米颗粒. 优化制备了CTS-lys原料, 红外(IR)和核磁(1H-NMR)检测结果表明壳聚糖的大量氨基被赖氨酸修饰. 通过共沉淀方法, 制备了赖氨酸修饰的壳聚糖磁性纳米颗粒(CTS-lys-MNPs). 利用透射电镜(TEM)、激光粒度分析仪、磁力计(VSM)和X射线衍射(XRD)对CTS-lys-MNPs进行了表征, 并通过U293细胞, 研究了CTS-lys-MNPs的细胞毒性. 结果表明, CTS-lys-MNPs的平均粒径为100 nm, 具有较好的超顺磁性和较低的细胞毒性; 在此基础上, 通过凝胶电泳实验观察了CTS-lys-MNPs和DNA的结合情况, 并通过单光子发射型计算机断层显像仪(SPECT) 研究了CTS-lys-MNPs和DNA的复合物在动物体内跨越血脑屏障的能力. 结果表明, CTS-lys-MNPs 是一种较好的磁靶向基因载体并能成功地跨越血脑屏障. 相似文献
998.
Francesco Borchi Monica Carfagni Lorenzo Martelli Alessio Turchi Fabrizio Argenti 《Applied Acoustics》2016
Active noise control (ANC) techniques are based on the emission of an antiphase signal in order to cancel the noise produced by a primary source. ANC has been successfully applied especially for reducing noise in confined environments, such as headphones and ducts. In this study, we present an application of ANC concepts to the design of an anti-noise barrier for an outdoor environment and its experimental testing. Even though passive techniques are effective in noise reduction at middle-high frequencies, they become less efficient at low frequencies (below 300 Hz) due to the limited dimensions of commonly deployable barriers. In this paper, we analyze the properties of a low-cost active noise system able to efficiently operate on stationary, almost pure-tone, low-frequency noise, such as that produced by electrical transformers and reactors in power and transformation plants. A prototype has been implemented and on-the-field experimental tests have been carried out. The results (confirmed also by numerical simulations) demonstrate a remarkable efficiency in the far field, with a reduction up to 15 dB with respect to the absence of the ANC system. 相似文献
999.
Hydrogen spillover has attracted increasing interests in the field of electrocatalytic hydrogen evolution reaction (HER) in recent years because of their distinct reaction mechanism and beneficial terms for simultaneously weakening the strong hydrogen adsorption on metal and strengthening the weak hydrogen adsorption on support. By taking advantageous merits of efficient hydrogen transfer, hydrogen spillover-based binary catalysts have been widely investigated, which paves a new way for boosting the development of hydrogen production by water electrolysis. In this paper, we summarize the recent progress of this interesting field by focusing on the advanced strategies for intensifying the hydrogen spillover towards HER. In addition, the challenging issues and some perspective insights in the future development of hydrogen spillover-based electrocatalysts are also systematically discussed. 相似文献
1000.
İsa Doğan Atik B. Özen F. Tıhmınlıoğlu 《Journal of Thermal Analysis and Calorimetry》2008,94(3):687-693
The novel film structure of corn-zein coated on polypropylene (PP) synthetic film for packaging industry was developed to
examine the feasibility of resulting coated films as an alternative water barrier performance for food packaging. The effects
of coating formulation (solvent, corn-zein, plasticizer concentration and plasticizer type) on final properties of films were
observed. Corn-zein is the most important protein of corn and has good film forming property. Composites structures of PP
films coated with corn-zein were obtained through a simple solvent casting method. Polyethylene glycol (PEG) and glycerol
(GLY) were used as plasticizer to increase film flexibility. Statistical analysis based on full factorial design was performed
to observe coating formulation effects. The high water vapour barriers were obtained for films coated with coating formulation
consisting of higher amounts of corn-zein plasticized by GLY. The lower glass transition temperatures (T
g) of films were obtained by plasticization of films and T
g decreased by increasing plasticizer content. The statistical analysis defined the key parameters of coating formulation that
had major effects on the final properties of coated PP films as corn-zein, plasticizer concentration and plasticizer type.
In conclusion, corn-zein coatings could have potential as an alternative to conventional synthetic polymers used in composite
multilayer structures for food packaging applications. 相似文献