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71.
纳米纺织纤维的制造技术 总被引:2,自引:0,他引:2
本文介绍了海岛法、电子纺丝法、直接聚合法制造纳米直径纤维的技术,并按纳米纤维功能分类介绍了机理,列举了纳米纤维的用途及其产品,指出了纳米纺织纤维研究、生产应注意的问题。 相似文献
72.
Lianfeng Guo Wenguang Zhang and Chengtao WangSchool of Mechanical Power Engineering Shanghai Jiaotong University Shanghai China 《北京科技大学学报(英文版)》2004,(5)
Nanoparticle hydroxyapatite was prepared by a wet chemical precipitation method. The effects of different synthesis conditions, i.e. contents of reagents (0.2, 0.5 and 0.8 mol/L), reaction temperatures (20, 37, 55 and 75℃) and reaction time (0-24 h), were studied based on crystallization process analysis and the effects of washing methods (with water or alcohol) were also studied. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), electron diffraction (ED) and inductively coupled plasma spectroscopy (ICP) were used to characterize the powders. Chemical analysis shows that the purity of the precipitated hydroxyapatite largely depends on reaction time. X-ray diffraction and TEM micrographs results show that reaction temperature is a key factor affecting crystallinity, morphology and particle size. Degree of supersaturation and stirring also affects the crystallization. Particles are in a shape of short rod and have a size of 20-40 nm in lengt 相似文献
73.
V. Hiremath 《塑料、橡胶和复合材料》2016,45(5):199-206
Nanocomposites were synthesised by dispersing two different types of alumina nanoparticles in epoxy matrix by ultrasonication. Alumina nanoparticles of two shapes, rod and spherical were selected to investigate the effect of particle morphology on viscoelastic and flexural properties of nanocomposites. Specific surface area of both the selected nanoparticles was kept in the similar range. Good dispersion of nanoparticles was observed through transmission electron microscopy. The addition of nanoparticles in epoxy had significant enhancement in the viscoelastic properties and moderate improvement in flexural properties of composites. Composites having alumina nanorods showed higher improvement both in storage modulus as well as in flexural properties in comparison to composites having spherical alumina nanoparticles. Efficacy of Mori-Tanaka method was explored in modelling storage modulus of nanocomposites. Assorted size of alumina nanorods based on particle size distribution was used to model composites with nanorods to see the effect of size assortment on storage modulus. 相似文献
74.
75.
A facile approach to prepare a thin film vapor sensor is demonstrated through droplet interfacial reaction on an IDA microelectrode.Scanning electron microscopy,atomic force microscopy and transmission electron microscopy analyses show that the film of the vapor sensor is composed of self-assembled gold nanocrystals in an average diameter of about 4.3 nm.The as-prepared sensor was examined by potential step method and impedance measurement,which exhibited significant A/?//?,responses and excellent cycle performance to the volatile organic compound(VOC) vapors of acetone,methanol,styrene,benzene,toluene and ethanol.The selectivity to the VOCs with benzene ring or organic solvents suggests that the sensor is probably in line with the swelling and dielectric sensing mechanisms. 相似文献
76.
Complete fusion of two selected cells allows for the creation of novel hybrid cells with inherited genetic properties from both original cells.Alternatively,via fusion of a selected cell with a selected vesicle,chemicals or genes can be directly delivered into the cell of interest,to control cellular reactions or gene expression.Here,we demonstrate how to perform an optically controlled fusion of two selected cells or of one cell and one vesicle.Fusion is mediated by laser irradiating plasmonic gold nanoparticles optically trapped between two cells (or a vesicle and a cell) of interest.This hot-particle-mediated fusion causes total mixing of the two cytoplasms and the two cell membranes resulting in formation of a new hybrid cell with an intact cell membrane and enzymatic activity following fusion.Similarly,fusion between a vesicle and a cell results in delivery of the vesicle cargo to the cytoplasm,and after fusion,the cell shows signs of viability.The method is an implementation of targeted drug delivery at the single-cell level and has a great potential for cellular control and design. 相似文献
77.
Two types of glass fiber reinforced plastic (GFRP) composites were fabricated viz., GFRP with neat epoxy matrix (GFRP-neat) and GFRP with hybrid modified epoxy matrix (GFRP-hybrid) containing 9 wt.% of rubber microparticles and 10 wt.% of silica nanoparticles. Fatigue tests were conducted on both the composites under WISPERX load sequence. The fatigue life of the GFRP-hybrid composite was about 4–5 times higher than that of GFRP-neat composite. The underlying mechanisms for improved fatigue performance are discussed. A reasonably good correlation was observed between the experimental fatigue life and the fatigue life predicted under spectrum loads. 相似文献
78.
《Microelectronics Reliability》2014,54(9-10):1867-1871
Power cycle reliability of Cu nanoparticle joint has been studied for high temperature operation of power devices. Al2O3 heater chips and Cu–65 wt% Mo baseplates were joined by Cu nanoparticles and Sn–0.7Cu and power cycle tests of 65/200 °C and 65/250 °C were carried out on the joints. The Cu nanoparticles were prepared by reducing Cu carbonate in ethylene glycol with dodecanoic acid + dodecyl amine (C12) and decanoic acid and decyl amine (C10) as capping agents. A power cycle test of 65/200 °C did not inflict severe damage on the Cu nanoparticle joints so that there were not many cracks formed after 3000 cycles. Vertical cracks were formed in the C12 Cu nanoparticle joint after 3000 cycles of 65/250 °C test, however the maximum temperature during the power cycle test did not change at all because vertical cracks did not have an effect on preventing heat flow. On the contrary, lateral cracks were completely formed in the Sn–0.7Cu soldered joint after 200 cycles of 65/200 °C test and in the C10 Cu nanoparticle joint after 360 cycles of 65/250 °C test. In these experiments, the maximum temperatures were rapidly increased because heat conduction was prevented across the formed lateral cracks. 相似文献
79.
《International Journal of Hydrogen Energy》2021,46(72):35692-35705
A novel and high-efficiency Pd/TMxOy-rGO/CFP (TMxOy = Co3O4, Mn3O4, Ni(OH)2) electrocatalyst for directly integrated membrane electrode was synthesized by controllable cyclic voltammetry electrodeposition combined with hydrothermal process. The results showed excellent performance towards methanol oxidation reduction. The Pd/Co3O4-rGO/CFP as-prepared catalyst has the best electrocatalytic activity, and mass activity is 5181 mA·mg−1Pd, which is about 40 times and 4.3 times that of the commercial Pd/C and Pt/C catalyst (JM). It can be attributed that the small size of Pd nanoparticle, uniformity of distribution, and the synergistic interaction between transition metal oxide on the support surface and Pd nanoparticles. The prepared Pd/TMxOy-rGO/CFP composite electrode is a promising catalyst for integrated membrane electrode assembly of proton exchange membrane fuel cells in the future. 相似文献
80.
Elnaz Farzinfar 《国际聚合物材料杂志》2019,68(11):628-638
Polymeric hydrogels, water-swollen 3?D networks of the polymers, have found wide ranges of applications in the medical fields, such as wound care and wound dressing, in order to prevent infections. Prevention from microorganisms transfer in to the wounds is one of the ideal wound dressing duties of polyvinyl alcohol (PVA) hydrogels. In this study, at the start, under optimal conditions, nanoparticles of chitosan using ionotropic gelation method were synthesized and in the next step in order to achieve particles with a minimum size, they were evaluated by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). Then after to obtain a wound dressing with preferable properties, nanocomposite hydrogels using a combination of PVA and 5, 10 and 15?wt% chitosan nanoparticles were prepared through freezing-thawing cycles. The necessary features of PVA nanocomposite hydrogels for wound dressing were investigated. The dispersion state of nanoparticles and structure of samples were evaluated by SEM microscopy. The nanoparticle size and the nanoparticle size distribution of chitosan was determined using the dynamic light scattering test at the nanometer scale. The physical behavior of hydrogels such as swelling and gel fraction was studied and their mechanical properties were investigated by compressive test. Finally the antimicrobial test and biocompatibility as cell viability were carried out. The results proved that the PVA nanocomposite hydrogels fulfill the requirements of a good wound dressing with desirable characteristics such as favorable swelling and acceptable strength, excellent barrier against microbial penetration. 相似文献