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排序方式: 共有1379条查询结果,搜索用时 16 毫秒
101.
A theoretical analysis of the drying process occurring inside the household electric tumbler clothes-dryer is performed to determine various thermo-physical parameters affecting the energy consumption and for the development of a simulation model. Experiments are conducted on a test set-up, based on a compact tumble-dryer, to measure the values of the parameters necessary for evaluating the performance. Widely-accepted economy standards are considered for comparison of simulation and experimental results. The simulation results are in reasonable agreement with experimental data. An empirical correlation for the specific moisture-extraction rate (SMER) is developed to translate energy-consumption information from one standard to the other. 相似文献
102.
The effect of admixing of aluminium phosphate on oxychloride cement in the matrix has been investigated. It is shown that
aluminium phosphate retards the setting process of the cement and improves water-tightness. 相似文献
103.
Vineet Kumar Sudesh Kumar Yadav 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(2):151-157
Nanobiotechnology deals with the synthesis of nanostructures using living organisms. Among the use of living organisms for nanoparticle synthesis, plants have found application particularly in metal nanoparticle synthesis. Use of plants for synthesis of nanoparticles could be advantageous over other environmentally benign biological processes as this eliminates the elaborate process of maintaining cell cultures. Biosynthetic processes for nanoparticles would be more useful if nanoparticles were produced extracellularly using plants or their extracts and in a controlled manner according to their size, dispersity and shape. Plant use can also be suitably scaled up for large‐scale synthesis of nanoparticles. In view of this, we have reviewed here the use of plants or their extracts in the synthesis of silver and gold nanoparticles for various human applications. Copyright © 2008 Society of Chemical Industry 相似文献
104.
The effect of standard heat treatment on the microstructure and mechanical properties of Ni–Fe base super-alloy, Inconel 718 was studied by optical microscopy and ball indentation technique (BIT) using small amount of specimen. In order to get good ductility, good formability, yield, tensile and creep rupture, as-received material was given the standard heat treatment, viz solution treatment at two temperatures 940 °C and 1040 °C for1 h and water quenched (WQ) followed by aging treatment at 720 °C for 8 h. and furnace cooling (FC). The BIT has revealed that the strengths for as-received material are maximum compared to other heat-treated materials. After solution treatment there has been a radical decline in strength. But the ageing causes a significant enhancement of strength. Optical microscopy studies supported the obtained BIT results. γ″-phase is the basic strengthening phase in 718 alloys. 相似文献
105.
Gd-doped BiFeO3 polycrystalline ceramics were synthesized by solid-state reaction method and their dielectric and magnetic properties were investigated. X-ray diffraction pattern showed that Bi1 − xGdxFeO3 (x = 0, 0.05 and 0.1) ceramics were rhombohedral. The Gd substitution has suppressed the usual impurity peaks present in the parent compound and we obtained single phase Bi0.9Gd0.1FeO3 ceramic. Gd substitution reduced the antiferromagnetic Néel temperature (TN) in Bi1 − xGdx FeO3. An anomaly in the dielectric constant(ε) and dielectric loss(tan (δ)) in the vicinity of the antiferromagnetic Néel temperature (TN) was observed. Ferroelectric and magnetic hysteresis loops measured at room temperature indicated the coexistence of ferroelectricity and magnetism. The room temperature magnetic hysteresis loops were not saturated, but the magnetic moment was found to increase with increase in Gd concentration. 相似文献
106.
The present study reports a simple and low cost synthesis of zero‐valent silver nanoparticles (ZVSNPs) from silver nitrate using the leaf extract of Spondias dulcis. The ZVSNPs showed a unique peak at 420 nm in UV–vis spectrum. The SEM image portrayed cuboidal shaped particles. The EDX spectrum designated the elemental silver peak at 3 keV. In XRD, a sharp peak at 32.47° denoted the existence of (1 0 1) lattice plane and the average crystallite size was calculated as 48.61 nm. The lattice parameter was determined as 0.39 nm. The FTIR spectra of the leaf extract and ZVSNPs showed shifts in the specific functional group bands which ascertained the involvement of phytoconstituents in the formation and capping of nanoparticles. The average hydrodynamic size was measured as 59.66 nm by DLS method. A low PDI, 0.187 witnessed the monodispersity. A negative zeta potential value of −15.7 mV indicated the negative surface charges of the nanoparticles. The bactericidal action of ZVSNPs was demonstrated against two pathogens S.typhimurium and E.coli during which a dosage dependent zone of inhibition results was observed. Additionally, the catalytic potential of ZVSNPs was examined for the degradation of methylene blue dye in which an accelerated degradation of the dye was observed.Inspec keywords: antibacterial activity, crystallites, electrokinetic effects, scanning electron microscopy, nanoparticles, particle size, ultraviolet spectra, X‐ray chemical analysis, microorganisms, light scattering, nanofabrication, materials preparation, X‐ray diffraction, visible spectra, silver, dyes, Fourier transform infrared spectraOther keywords: wavelength 420.0 nm, Ag, voltage ‐15.7 mV, size 59.66 nm, size 0.39 nm, size 48.61 nm, electron volt energy 3.0 keV, Fourier transform infrared spectra, methylene blue dye, bactericidal action, dynamic light scattering, lattice parameter, Escherichia coli, Salmonella typhimurium, Spondias dulcis, negative zeta potential, polydispersity index, crystallite size, leaf extract, X‐ray diffraction, energy dispersive X‐ray spectrum, cuboidal‐shaped particles, scanning electron microscopy image, ultraviolet–visible spectrum, silver nitrate, zero‐valent silver nanoparticles 相似文献
107.
Bal K Agrawal S Agrawal P S Yadav S Kumar J S Negi Namrata Varshney 《Bulletin of Materials Science》1991,14(4):967-971
In the series of the layered highT
c
superconductors (A)1,2 B2Ca
n−1Cu
n
O2n+3,4 (A=Tl or Bi;B=Ba or Sr), withn=number of consecutive Cu-O layers, the electron energy states of some of the Tl-based systems have been investigated. The
electron and phonon dispersion curves have been obtained. The electronic states near the Fermi level are dominated by the
hybridized Cu(d) and the O(p) orbitals. The dispersion curves are highly two-dimensional with very small dispersion alongc-axis. The number of bands is enhanced with increase in the number of the consecutive Cu-O planes (n). The present results agree with those obtained earlier for other superconducting phases. The phonons are overall dominated
by the vibrations of the light mass oxygen atom modes both lying in or outside the Cu-O planes. The low-frequency phonons
involve the motions of the heavier Tl, Ba atoms etc. 相似文献
108.
Blend samples of cardanol-based epoxidized novolac resin and different weight percentages of carboxyl-terminated butadiene
acrylonitrile (CTBN) were developed and cured with stoichiometric amounts of aliphatic amine. The formation of various products
during the curing of blend samples has been studied by Fourier-transform infrared spectroscopy. The dynamic differential scanning
calorimeter scans showed that the pure epoxies and their blend samples with CTBN cured in the temperature range of 100–150°C.
The blend sample containing 15 wt% CTBN showed the least cure time (at 120°C) among all other blend samples. Upon evaluation,
it was found that blend samples exhibit better properties compared to pure epoxy resin in terms of increase in impact strength
and elongation-at-break of the casting and gloss, scratch hardness, adhesion, and flexibility of the film. The improvement
in these properties indicates that the rubber modified resin would be more durable than the epoxy based on cardanol. Chemical
and morphological properties of the formulated resins were also determined. The thermal stability of the blend samples containing
15 wt% CTBN in epoxy resin was the highest among all other prepared systems. The blend morphology, studied by scanning electron
microscope, showed the presence of precipitated discrete rubber particles, which dispersed throughout the epoxy matrix—i.e.,
they revealed the presence of two-phase morphological features. 相似文献
109.
Rajesh Patel VishnuP. Srivastava Lal DharS. Yadav 《Advanced Synthesis \u0026amp; Catalysis》2010,352(10):1610-1614
The first procedure to access N‐tosylimines directly from alcohols under mild and neutral conditions is reported. The protocol involves saccharin‐lithium bromide‐catalyzed oxidation of alcohols to aldehydes/ketones with chloramine‐T followed by their condensation with the in situ generated oxidation by‐product p‐toluenesulfonamide in the same reaction vessel to afford N‐tosylimines in 40–90% overall yields. The present work opens up a new and efficient synthetic route to N‐tosyimines directly from alcohols in a one‐pot procedure. 相似文献
110.
Silicon - In this paper, we have studied effect of localised charges on performance of UTBB FDSOI FET. Purpose behind this work is to understand the performance of UTBB FDSOI FET under the... 相似文献