排序方式: 共有72条查询结果,搜索用时 15 毫秒
51.
Acar H Garifullin R Guler MO 《Langmuir : the ACS journal of surfaces and colloids》2011,27(3):1079-1084
Mineralized biological materials such as shells, skeleton, and teeth experience biomineralization. Biomimetic materials exploit the biomineralization process to form functional organic-inorganic hybrid nanostructures. In this work, we mimicked the biomineralization process by the de novo design of an amyloid-like peptide that self-assembles into nanofibers. Chemically active groups enhancing the affinity for metal ions were used to accumulate silicon and titanium precursors on the organic template. The self-assembly process and template effect were characterized by CD, FT-IR, UV-vis, fluorescence, rheology, TGA, SEM, and TEM. The self-assembled organic nanostructures were exploited as a template to form high-aspect-ratio 1-D silica and titania nanostructures by the addition of appropriate precursors. Herein, a new bottom-up approach was demonstrated to form silica and titania nanostructures that can yield wide opportunities to produce high-aspect-ratio inorganic nanostructures with high surface areas. The materials developed in this work have vast potential in the fields of catalysis and electronic materials. 相似文献
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53.
Handan Engin Kirimli 《Journal of Dispersion Science and Technology》2014,35(2):255-264
A variety of analytical techniques, such as scanning electron microscopy and 19F dynamic nuclear polarization (DNP) methods, are applied to characterize asphaltene extracted from MC-800 liquid asphalt in fluorobenzene derivatives at 1.53 mT and at room temperature. Different solvents show variable affinities for the asphaltene surface. The low field EPR spectrum of the asphaltene/hexafluorobenzene sample was recorded. The DNP parameters were determined. Additionally, the interactions between the nuclei of the solvent and the electrons delocalized on the asphaltene are interpreted. Not only dipolar but also scalar interactions between the nuclear spin and the electron spin were found. 相似文献
54.
Handan Cerid 《European Polymer Journal》2004,40(3):579-587
The spatial inhomogeneity in polystyrene (PS) gels has been investigated with the static light scattering technique. PS gels were prepared starting from styrene monomer and ethylene glycol dimethacrylate crosslinker in a homogeneous solution. The gel synthesis parameters varied were the crosslinker concentration, the primary chains length and the quality of the polymerization solvent. The gels were characterized by elasticity tests as well as by light scattering measurements at a gel state just after their preparation. The degree of spatial gel inhomogeneity decreased with decreasing crosslinker content, with decreasing primary chain length or, with increasing quality of the polymerization solvent. It was shown that the gel synthesis parameters varied mainly affect the distance between the pendant vinyl groups locating on the same macromolecule during the gel formation process. Increasing the distance between the pendant vinyl groups reduces the rate of the multiple crosslinking reactions so that the resulting PS gels exhibit a lesser degree of inhomogeneity. 相似文献
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对氮作稀释剂DF化学激光器的实用化途径进行探讨,对实验输出性能进行分析研究,并与一般的氦稀释剂DF激光器性能作一比较,结果表明,单从器件本身输出性能来说,氮稀释剂略次于氦稀释剂,但从综合性能考虑,氮稀释剂DF化学激光器仍是实用型器件理想的候选者之一。 相似文献
56.
Salim Yüce 《数学物理学报(B辑英文版)》2011,31(1):172-180
In this article, we give the area formula of the closed projection curve of a closed space curve in Lorentzian 3-space L3. For the 1-parameter closed Lorentzian space motion in L3, we obtain a Holditch Theorem taking into account the Lorentzian matrix multiplication for the closed space curves by using their othogonal projections onto the Euclidean plane in the fixed Lorentzian space. Moreover, we generalize this Holditch Theorem for noncollinear three fixed points of the moving Lorentzian space and any other fixed point on the plane which is determined by these three fixed points. 相似文献
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Anti-low density lipoprotein antibody (anti-LDL) molecules were attached covalently and oriented through Protein A onto poly(2-hydroxyethyl methacrylate-ethylene glycol dimethacrylate) [poly(HEMA-EGDMA)] beads in order to remove cholesterol specifically from hypercholesterolemic human plasma. Poly(HEMA-EGDMA) beads were produced by suspension polymerization. Blood compatibility tests were performed. All the clotting times were increased when compared with control plasma. Loss of platelets and leukocytes was very low. The maximum anti-LDL attachment was 11.6 mg . g(-1) in the case of random immobilization and 28.3 mg . g(-1) in the case of oriented immobilization. In the latter case, Protein A loading was 8.3 mg . g(-1) at pH 7.5 (borate buffer, 0.15 M NaCl). There was low non-specific cholesterol adsorption onto the poly(HEMA-EGDMA) beads, about 0.83 mg . g(-1). Random and oriented anti-LDL attached beads adsorbed 8.2 mg and 11.7 mg cholesterol per g of bead from hypercholesterolemic human plasma, respectively. Up to 96% of the adsorbed cholesterol was desorbed. The binding-elution cycle was repeated 6 times using the same beads. There was no significant loss of binding capacity. 相似文献
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A Galvanic cell was designed based on the acid-base neutralization reaction by undergraduates according to the electrochemical theory in physical chemistry. By carrying out the comprehensive experiments, the learning interest of undergraduates on physical chemistry was inspired. The understanding on the principle of electrochemistry was enhanced. In addition, the undergraduates also established an intuitive understanding on scientific research by combining the experiments with the theory. It is helpful to broaden the academic horizons of the undergraduates and strengthen their ability to apply theoretical knowledge to practice. The work is a beneficial exploration to innovate the teaching mode of physical chemistry. 相似文献
59.
田伶改 《高等学校计算数学学报(英文版)》2004,13(1):24-30
Some properties of the preconditioned gradient conjugate method are given.It may happen that loss of significant digits, when the norm of residual is very small. Toavoid this, a variant algorithm which does not use the residual is put forward. 相似文献
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Handan Akpinar Şevki Can Cevher Lang Wei Ali Cirpan Bryan M. Wong Dhandapani Venkataraman Paul M. Lahti 《Journal of Polymer Science.Polymer Physics》2015,53(21):1539-1545
Poly((2‐Alkylbenzo[1,2,3]triazole‐4,7‐diyl)vinylene)s (pBTzVs) synthesized by Stille coupling show different absorption spectra, solid‐state morphology, and photovoltaic performance, depending on straight‐chain versus branched‐chain (pBTzV12 and pBTzV20) pendant substitution. Periodic boundary condition density functional computations show limited alkyl pendant effects on isolated chain electronic properties; however, pendants could influence polymer backbone conjugative planarity and polymer solid film packing. The polymers are electronically ambipolar, with best performance by pBTzV12 with hole and electron transport mobilities of 4.86 × 10?6 and 1.96 × 10?6 cm2 V?1 s?1, respectively. pBTzV12 gives a smooth film morphology, whereas pBTzV20 gives a very different fibrillar morphology. For ITO/PEDOT:PSS/(1:1 w/w polymer:PC71BM)/LiF/Al devices, pBTzV12 gives power conversion efficiency (PCE) up to 2.87%, and pBTzV20 gives up to PCE = 1.40%; both have open‐circuit voltages of VOC = 0.6–0.7 V. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1539–1545 相似文献