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41.
Two kinds of nano TiO2-polyacrylate hybrid dispersions, TBM-w and TBM-e were synthesized by in-situ suspension polymerization and solution polymerization respectively, in order to fix the nano TiO2 on fabrics. The photocatalytic self-cleaning fabrics have received much attention in recent years for its water-saving and environment-protection advantages. However, the fixation of the photocatalyst on fabrics is still a key problem that inhibits industrialization of these eco-friendly fabrics. The cotton fabric was treated by the two hybrid dispersions. The photocatalytic self-cleaning property was characterized. Infrared spectroscopy, burning loss test and thermogravimetry showed that some copolymer chains entangled with the nano TiO2. Transmission electron microscope illustrated that there was a polymeric layer on the surface of nano TiO2. The average diameter of TBM-w was smaller than that of TBM-e based on size analysis. The photocatalytic decoloration of the grape syrup indicated that the fabric with TiO2-polymer hybrid had excellent self-cleaning property. 相似文献
42.
G. Cynthia Jemima SwarnavalliV. Joseph D. RoopsinghV. Kannappan 《Journal of Molecular Liquids》2011,164(3):243-249
Nanocrystallite silver and silver sol were prepared and characterized by UV-visible spectra, XRD, TEM and HRTEM. The crystallite silver is re-dispersed in two different media, namely, water and alcohol and sonicated before ultrasonic investigation. The silver sol was used as such. Three different models for the propagation of ultrasound through two phase media are compared in these three different types of nano suspensions. Effect of particle size and medium on ultrasonic velocity (U), compressibility (κ) impedance (Z) and viscous relaxation time (τ) is studied. The particle concentration range was 0.2-1 v/v. Density and viscosity of the dispersion and sol are measured at different particle volume fractions. Effective density and ultrasonic velocity are computed by Urick, Kuster and Toksöz and Urick and Ament models and compared with experimental velocities. Values of effective density obtained by using Urick and Urick and Ament equations closely agree with experimental results of density while Urick's equation prediction of velocity is in close agreement with the experimental velocities. This comes as a surprise in view of the large density difference between the medium and suspended particle and suggests the possibility of the balancing effect of the inertial and viscous forces operating in the suspension. 相似文献
43.
Hiromichi Aono Hiroki Ebara Ryota Senba Takashi Naohara Tsunehiro Maehara Hideyuki Hirazawa Yuji Watanabe 《Journal of magnetism and magnetic materials》2012
Nano-sized magnetic Y3Fe5O12 ferrite having a high heat generation ability in an AC magnetic field was prepared by bead milling. A commercial powder sample (non-milled sample) of ca. 2.9 μm in particle size did not show any temperature enhancement in the AC magnetic field. The heat generation ability in the AC magnetic field improved with a decrease in the average crystallite size for the bead-milled Y3Fe5O12 ferrites. The highest heat ability in the AC magnetic field was for the fine Y3Fe5O12 powder with a 15-nm crystallite size (the samples were milled for 4 h using 0.1 mm? beads). The heat generation ability of the excessively milled Y3Fe5O12 samples decreased. The main reason for the high heat generation property of the milled samples was ascribed to an increase in the Néel relaxation of the superparamagnetic material. The heat generation ability was not influenced by the concentration of the ferrite powder. For the samples milled for 4 h using 0.1 mm? beads, the heat generation ability (W g−1) was estimated using a 3.58×10−4 fH2 frequency (f/kHz) and the magnetic field (H/kA m−1), which is the highest reported value of superparamagnetic materials. 相似文献
44.
45.
We investigated the internal dynamics of an electro-fluid shuttle memory element, consisting of K+@C60 and F−@C60 encapsulated in a C640 nanocapsule. Energetics and operating responses of bipolar endo-fullerenes shuttle memory device, (K+@C60–F−@C60)@C640, were examined by classical molecular dynamics simulations under the external force fields. 相似文献
46.
D.L. Wainstein A.I. Kovalev Cs. Ducso T. Jaszi P. Basa Zs.J. Horvath T. Lohner P. Petrik 《Physica E: Low-dimensional Systems and Nanostructures》2007,38(1-2):156
Si nanocrystals were formed in the non-stoichiometric Si-enriched SiNx low-pressure chemical vapor deposited (LPCVD) coatings on Si wafers treated by various modes. The coating structure as a function of technological conditions was investigated by ellipsometry and X-ray photoelectron spectroscopy (XPS) depth profiling. It was found that nanocomposites on base of SiNx films enriched by Si have a complex multilayered structure varying in dependence of deposition and annealing parameters. Analysis of the XPS spectra and Si 2s peaks shows the existence and quantity of four chemical structures corresponding to the Si–O, Si–N states, nanocrystalline and amorphous Si. The XPS results show evolution of the chemical structure of silicon nitride and formation of Si nanocrystals. It was found:
- • The LPCVD technology of nanocrystals formation allows to get enough high concentration of Si nanocrystals on different depths from the sample surface.
- • The volume fraction of nanocrystalline and amorphous Si is changed with depth; this relation depends from SiNx composition and annealing parameters.
- • XPS detects these two phase compositions of Si nanoparticles in SiNx and SiO2 layers. The ellipsometry, HR-TEM, and XPS results are in good agreement.
Keywords: Nano crystals; Si 相似文献
47.
《Comptes Rendus Chimie》2015,18(8):848-857
An efficient, rapid and green synthesis of α,α′-bis(substituted-benzylidene)cycloalkanones and their xanthene derivatives is reported under solvent-free conditions using nano titania-supported sulfonic acid (n-TSA) as a reusable catalyst. This method offers many advantages, such as environmental friendliness reaction conditions, simplicity, short reaction times, easy work-up, reusability of catalyst, and high yields of products. Eight new compounds are reported too. 相似文献
48.
利用阿维菌素具有2个活性羟基的特性,设计合成了一种具有阿维菌素结构单元的阴离子型聚氨酯分散剂,采用核磁共振和红外光谱表征了其结构.利用分散剂与阿维菌素结构的相似性,将溶有阿维菌素的分散剂溶液加入水中,制备了阿维菌素的纳米水分散体.研究分散剂中羧基含量及其分子量对分散体粒径的影响,结果表明,随着羧基含量的增加,分散体粒径逐渐降低,适当控制分子量有助于改善分散剂的分散能力.透射电镜显示分散粒子具有近似球形的形貌,粒径在20~40 nm之间.纳米分散体具有较高的离心稳定性和稀释稳定性. 相似文献
49.
The nano SnO2-modified LiNi1/3Co1/3Mn1/3O2 was successfully prepared by a carrier transfer method. The pristine and modified samples were characterized with various techniques such as XRD, SEM, XPS and EDS. The results showed that the SnO2 particles did not enter the crystal structure of LiNi1/3Co1/ 3Mn1/3O2, many nano SnO2 particles were uniformly covered on the surface of LiNi1/3Co1/3Mn1/3O2 and the modified thin layer could inhibit the dissolution of transition metal oxides. The electrochemical tests indicated that the existence of nano SnO2 could improve the discharge capacity and rate capability owing to the decreased interfacial polarization. The cycling stability was remarkably improved at room temperature and 55 ℃. The XRD patterns of the fresh NCM electrode and after 50 cycles proved that the structural change of NCM was not so effective on the capacity fade. 相似文献
50.