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951.
The miscibility of various polymethylmethacrylate (PMMA)/polybutylmethacrylate (PBMA)/poly(methylmethacrylate-co-butylmethacrylate)systems has been studied. PMMA and PBMA are immiscible. Methacrylic homopolymers and copolymers are immiscible, too. A one-phase mixture from PMMA and PBMA is only accessible by copolymerization. 相似文献
952.
A series of asphalt–polyurethane composites was prepared by means of polyurethane synthesis in asphalt and carried out in melt. The applied materials were asphalts of differentiated group components content, polyester polyols of chain structure from linear to strongly branched, 2,4-tolylene diisocyanate, 4,4-methylenebis(phenyl isocyanate), and tinorganic catalyst. The asphalt components react with isocyanates to a minimal degree. The influence of the applied substrates, temperature, and polyurethane content in the system on the basic kinetic relations characterizing the process is presented. Polyurethane synthesis in asphalts does not differ in a fundamental way from the obtaining of polyurethanes, especially when their content in the composition is significant, 20 wt % and more. 相似文献
953.
Jacek Kijowski & R. Ian Richardson 《International Journal of Food Science & Technology》1996,31(1):45-54
Mechanically recovered meat (MRM) from broilers was washed three times with water and subjected to either slow or rapid freezing or freeze-drying with, or without, the presence of cryoprotectants. Both freezing and freeze-drying reduced the functionality of the MRM when no cryoprotectants were used. Sorbitol/sucrose showed some protection of gel forming ability of frozen samples whilst sorbitol/sucrose with tripolyphosphate gave stronger gels after freezing or freeze-drying than fresh samples. Most of the loss of functionality during freezing or freeze-drying was caused by loss of solubility of myosin and to a lesser extent actin. This was supported by DSC studies. The combined presence of sorbitol/sucrose/tripolyphosphate restored most functional properties of the frozen or freeze-dried material to that of the fresh material. 相似文献
954.
Biernat Jacek; Hasselmann Hanne; Hofer Bernd; Kennedy Nick; Koster Hubert 《Protein engineering, design & selection : PEDS》1987,1(4):345-351
Synthetic genes coding for artificial proteins with predeflnedand nutritionally valuable amino acid compositions have beenconstructed and cloned In bacterial plasmid vector pKK233-2.The genes were constructed from three easily interchangeablecassettes encoding either essential, non-essentialor branched-chain amino acid residues. A potential hairpin loopstructure in the mRNA around the region of the ribosome bindingsite was probably the reason for blockage of translation fromthis vector. Two selected genes, AHB (containing one copy ofeach cassette) and A (consisting of six copies concatemerizedA6cassette) were cloned into pUR300, a (ß-Gal fusionvector and expressed as fusion proteins (ß-Gal-AHBand (ß-Gal-A6. 相似文献
955.
Mehmet K. Muezzinoglu Author Vitae Jacek M. Zurada Author Vitae 《Pattern recognition》2006,39(5):747-760
Superposition of radial basis functions centered at given prototype patterns constitutes one of the most suitable energy forms for gradient systems that perform nearest neighbor classification with real-valued static prototypes. It is shown in this paper that a continuous-time dynamical neural network model, employing a radial basis function and a sigmoid multi-layer perceptron sub-networks, is capable of maximizing such an energy form locally, thus performing almost perfectly nearest neighbor classification, when initiated by a distorted pattern. The proposed design scheme allows for explicit representation of prototype patterns as network parameters, as well as augmenting additional or forgetting existing memory patterns. The dynamical classification scheme implemented by the network eliminates all comparisons, which are the vital steps of the conventional nearest neighbor classification process. The performance of the proposed network model is demonstrated on binary and gray-scale image reconstruction applications. 相似文献
956.
We have considered phonon-induced superconductivity on a square lattice. The antiferromagnetic correlations that are present in high-temperature superconductors (HTSC) have been simulated by the staggered magnetic field. The Eliashberg equations have been generalized to account for the momentum dependent order parameter, and the superconducting transition temperature T
c
has been evaluated within the strong-coupling theory. The two-dimensional band structure has explicitly been taken into account. It occurs that the results obtained for T
c
when considering d-wave symmetry of the superconducting state much better reflect the experimentally observed behavior than those derived for s-wave symmetry. The isotope shift exponent has also been evaluated. One can observe that the introduction of the staggered magnetic field leads to the decrease of this quantity. Therefore, the presence of the staggered magnetic field may contribute to experimentally observed values of smaller than the BCS value of 1/2 相似文献
957.
Magdalena Peruyska Aleksandra Borzyszkowska-Ledwig Jacek G. Sonicki ukasz Struk Tomasz J. Idzik Gabriela Maciejewska ukasz Skalski Katarzyna Piotrowska Pawe ukasik Marek Dro
dzik Mateusz Kurzawski 《International journal of molecular sciences》2021,22(5)
Most anticancer drugs target mitosis as the most crucial and fragile period of rapidly dividing cancer cells. However the limitations of classical chemotherapeutics drive the search for new more effective and selective compounds. For this purpose structural modifications of the previously characterized pyridine analogue (S1) were incorporated aiming to obtain an antimitotic inhibitor of satisfactory and specific anticancer activity. Structure-activity relationship analysis of the compounds against a panel of cancer cell lines allowed to select a compound with a thiophene ring at C5 of a 3,4-dihydropyridine-2(1H)-thione (S22) with promising antiproliferative activity (IC50 equal 1.71 ± 0.58 µM) and selectivity (SI = 21.09) against melanoma A375 cells. Moreover, all three of the most active compounds from the antiproliferative study, namely S1, S19 and S22 showed better selectivity against A375 cells than reference drug, suggesting their possible lower toxicity and wider therapeutic index. As further study revealed, selected compounds inhibited tubulin polymerization via colchicine binding site in dose dependent manner, leading to aberrant mitotic spindle formation, cell cycle arrest and apoptosis. Summarizing, the current study showed that among obtained mitotic-specific inhibitors analogue with thiophene ring showed the highest antiproliferative activity and selectivity against cancer cells. 相似文献
958.
张博文 颜伟 李兆峰 白龙 Grzegorz Cywinski Ivan Yahniuk Krzesimir Szkudlarek Czeslaw Skierbiszewski Jacek Przybytek Dmytro B. But Dominique Coquillat Wojciech Knap 杨富华 《红外与毫米波学报》2018,37(4):389-392
在场效应晶体管太赫兹探测器中,合理的天线设计可以增强晶体管和太赫兹波之间的耦合效率,从而提高太赫兹探测器的响应度.提出一种基于晶体管栅极边缘沟道电场的仿真来设计平面天线的方法.这种方法尤其适用于太赫兹波段晶体管输入阻抗不容易得到的情况.通过流片完成的基于氮化镓高电子迁移率晶体管的太赫兹探测器的响应度测试证实了这种方法的有效性.集成碟形天线和双偶极子天线的太赫兹探测器最大响应度分别在170.7 GHz(1568.4 V/W)和124.3 GHz(1047.2 V/W)频点处测得,这个测试结果接近基于晶体管栅极边缘沟道电场的仿真结果. 相似文献
959.
New generalized Newtonian fluid models for quantitative description of complex viscous behavior in shear flows
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Two semiempirical models of generalized Newtonian fluid are discussed. Special attention was focused on the stress dependent model based on the free volume theory. However, the strain‐rate dependent model in form of a modified viscosity function resulting from Oldroyd equation is also presented. Both models (along with specific cases) reflecting pseudoplastic or dilatant behavior of liquids in shear flows are generalized to multimode models (defined as products of two or more basic models), which are able to describe quantitatively the behavior of more complex systems, for example, systems with pseudoplastic and dilatant properties in different shear stress (shear rate) ranges. A number of practical examples for viscosity curves of non‐Newtonian fluids described by these models are given. The questions of inverse models and model efficiency are also discussed. POLYM. ENG. SCI., 58:1446–1455, 2018. © 2017 Society of Plastics Engineers 相似文献
960.
Jacek Andrzejewski Marek Szostak Mateusz Barczewski Janusz Krasucki Tomasz Sterzynski 《应用聚合物科学杂志》2014,131(23)
The results of this work relate to the use of co‐extrusion technology in the preparation of monocomposite pellets. The low‐melting polypropylene copolymer was used as a matrix material. The high strength polypropylene fibers were used as a fibrous reinforcement. Research confirms the possibility to produce the pellets with fibrous structure. The prepared composite material in the form of pellets was processed and shaped using the injection molding technology. Obtained samples were subjected to mechanical testing in the static tensile test and dynamic mechanical analysis. Research complements microscopic observation of scanning electron microscopy. The measurement results confirm the reinforcing effect of the fibers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41180. 相似文献