66 resultados para PBS
em Chinese Academy of Sciences Institutional Repositories Grid Portal
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<正> 用激光衍射仪测量RBC的变形性一般要求所用缓冲液的粘度高于18CP,以其获得稳定的,具有可比性的数据,常用的是不同浓度的右旋糖酐溶液。这在实用中带来两个问题;(1)粘度太高,故实验时红细胞所受剪切应力远高于生理水平;(2)价格昂贵,不利于临床推广。因此,我们试图寻求一种可以代替右旋糖酐溶液的新的缓冲液。本文中用了两种缓冲液,即PBS和15%PVP和四种不同的红细胞组成的悬浮液,用
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于AD批量导入至AEzhangdi
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Poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) capped PbS quantum dots about 3-6 nm in diameter were synthesized with a novel method. Unlike the synthesis of oleic acid capped PbS quantum dots, the reactions were carried out in solution at room temperature, with the presence of a capping ligand species, MDMO-PPV. The quantum dots were used to fabricate bulk heterojunction solar cells with an indium tin oxide (ITO)/polyethylenedioxythiophene/polystyrenesulphonate (PEDOT: PSS)/MDMO-PPV: PbS/Al structure. Current density-voltage characterization of the devices showed that after the addition of the MDMO-PPV capped PbS quantum dots to MDMO-PPV film, the performance was dramatically improved compared with pristine MDMO-PPV solar cells. (C) 2008 Elsevier Ltd. All rights reserved.
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Poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) capped PbS nanorods about 100 nm in diameter and 400 nm in length were synthesized via a hydrothermal route in toluene and dimethylsulfoxide solution. By blending the PbS nanorods with the MDMO-PPV as the active layer, bulk heterojunction solar cells with an indium tin oxide (ITO)/polyethylenedioxythiophene/polystyrenesulphonate (PEDOT PSS)/MDMO-PPV PbS nanorods/Al structure were fabricated in a N-2 filled glove box, Current density-voltage characterization of the devices showed that the solar cells with PbS nanorods hybrid with MDMO-PPV as active layer were better in performance than the devices with the polymer only. (C) 2009 Elsevier B.V. All rights reserved.
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聚对苯二甲酸丁二醇酯(PBT)是一种多用途的工程塑料。本文中,主要研究了PBT/Epoxy(E)合金及PBT/ABS-g-GMA/E合金的结晶行为和力学性能。 使用示差扫描量热法对PBT/Epoxy合金的等温结晶过程进行了研究。发现PBT和E03 609环氧树脂在所研究的组成范围内完全相容。环氧树脂起到异相成核剂的作用,使PBT产生更强的瞬间结晶三维生长趋势。PBT和环氧树脂的Flory相互作用参数为负值,说明PBT和环氧树脂形成了热力学上的稳定混合物。 使用几种方法对PBT/Epoxy合金的非等温结晶过程进行了研究,Ozawa方程不能充分描述PBT/Epoxy合金的非等温结晶过程;使用莫志深等人提出的方法,成功地描述了该过程。实验结果显示1%环氧树脂可使PBT/Epoxy合金结晶速率明显增加。 对PBT/Epoxy合金的热和力学性能进行了研究。1%环氧树脂的加入提高PBT/Epoxy合金的缺口冲击强度20%;从红外光谱分析,环氧树脂与PBT发生了相互作用;环氧树脂影响了PBT/Epoxy合金的力学性质和结晶行为。 采用乳液聚合技术将甲基丙烯酸环氧丙酯(GMA)引入到ABS的壳层,合成了环氧官能化的ABS共聚物(ABS-g-GMA),将环氧树脂加入到PBT/ABS-g-GMA合金中,利用环氧官能团与PBT端羧基/羟基的反应达到增容PBT/ABS合金的目的。当环氧树脂的含量为5%时,PBT/ABS-g-GMA/E共混物比PBT/ABS-g-GMA共混物有更优异的力学性质。 研究了聚亚丙基碳酸酯(PPC)和聚丁二酸二甲酯(PBS)共混物的相容性、结晶和力学性能。结果显示组份PPC/PBS(90/10)可能产生部分相容。采用偏光显微镜观察了PPC/PBS共混物的形态,对于90/10 PPC/PBS共混物,发现很大数量的PBS小球晶分散在PPC基质中。力学结果显示90/10 PPC/PBS共混物拉伸强度比纯PPC提高了30%,冲击强度提高了11%。
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PbS clusters in zeolite-Y have been prepared with the reaction of Pb2+-ion-exchanged zeolite-Y with Na2S in solution at room temperature. Their absorption spectra show dramatic blue shifts from that of the bulk PbS. Obvious change of both the absorption edges and peak positions upon PbS concentrations have been observed. These phenomena provide evidences that PbS clusters have been formed within the zeolite. The absorption spectra show featureless structure and have no tails near the absorption edges. As the PbS loading density becomes higher, the absorption bands become stronger and sharpen. Order PbS clusters lattice with high quality might be formed in the supercages of zeolite-Y. (C) 1996 American Institute of Physics.
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An interesting shape evolution of. PbS crystals, that is, from cubes to (truncated) octahedra and finally to stable star-shaped multipods with six arms along the < 100 > directions is first realized via a facile polyol-mediated reaction between lead acetate and sulfur powder in the absence of surfactants. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Fourier transform infrared (FT-IR) techniques were employed to characterize the samples. We elucidate the important parameters (including reaction temperature and sulfur sources) responsible for the shape-controlled synthesis of PbS crystals.
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Nanostructured PbS with different morphologies and particle sizes have been prepared through a polyol process. Narrow size distribution for star-shaped, octahedral, tetradecanehedral, and cubic products were achieved by slowly introducing the source materials using a peristaltic pump in the presence of poly(vinylpyrrolidone) (PVP) as additive. Systematic variation of the kinetic factors, including the additive, the reaction temperature, the duration time, the ratio of source materials, the Sulfur sources, and the Pb(Ac)(2)center dot 3H(2)O concentration, reveals that the morphology depends mainly on the supersaturation degree of the free sulfur ions released from thiourea under elevated temperature.
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In this paper, melt blends of poly(propylene carbonate) (PPC) with poly(butylene succinate) (PBS) were characterized by dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), tensile testing, wide-angle X-ray diffraction (WAXD), polarized optical microscopy and thermogravimetric analysis (TGA). The results indicated that the glass transition temperature of PPC in the 90/10 PPC/PBS blend was decreased by about 11 K comparing with that of pure PPC. The presence of 10% PBS was partially miscible with PPC. The 90/10 PPC/PBS blend had better impact and tensile strength than those of the other PPC/PBS blends. The glass transition temperature of PPC in the 80/20, 70/30, and 60/40 PPC/PBS blends was improved by about 4.9 K, 4.2 K, and 13 K comparing with that of pure PPC, respectively; which indicated the immiscibility between PPC and PBS. The DSC results indicated that the crystallization of PBS became more difficult when the PPC content increased. The matrix of PPC hindered the crystallization process of PBS. While the content of PBS was above 20%, significant crystallization-induced phase separation was observed by polarized optical microscopy. It was found from the WAXD analysis that the crystal structure of PBS did not change, and the degree of crystallinity increased with increasing PBS content in the PPC/PBS blends.
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本文用PBS和PVP两种介质作为激光衍射仪的悬浮介质,系统地观测了悬浮介质物化性能不同对红细胞变形指数(DI)—渗透压曲线的影响,发现:1.在不同悬浮介质中的变形指数—渗透压曲线有显著差别,在高渗区这种差别更明显.2.同一红细胞试样,在相同高渗压下,在不同的悬浮介质中进行交叉实验表明、PBS悬浮介质能使得红细胞变形性得到恢复,而PVP悬浮介质却使得红细胞变形性显著降低.3.在高渗情况下,首次观察到红细胞变形性随时间变化,一开始DI增大,约3小时后趋于稳定,无论PBS还是PVP其趋势皆相似.
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<正> 用激光衍射法测得的红细胞变形指数—渗透压曲线表征红细胞可变性与缓冲液渗透压之间的关系,它与红细胞的寿命有密切关系。本文用PBS和PVP两种介质作缓冲液,系统地观测了悬浮介质物化性能不同对于红细胞变形指数—渗透压曲线的影响。结果表明: 1.在不同悬浮介质中测得的变形指数—渗透压曲线有显著差别,在高渗区尤其明