Journal of Thermal Analysis and Calorimetry - In recent decades, the growth of heat transfer using nanomaterials in the conventional base fluid has caught the attention of researchers... 相似文献
In quasi-steady operation, convection currents in a Bridgmandevice, used for producing a semi-conductor crystal, createinhomogeneities that may make the crystal unusable. It has oftenbeen suggested that additional forces due to rotation or magnetismmight be efficacious in reducing the segregation of the elementsof the alloy. It has been found that, over a wide range of rotationrates, there is no improvement in performance due to rotationabout the vertical axis. However, numerical results that havebeen obtained previously (Lee & Pearlstein, J. Crys. Growth240, 2002) indicate that, when effects of centrifugal buoyancyare introduced, a substantial reduction in segregation is achieved.In the work reported here, by contrast, in which we extend previouslarge-Rayleigh-number asymptotic analysis to include centrifugalbuoyancy, we find no improvement in radial segregation, butrather increasing segregation with increasing rotation rate. 相似文献
A modest, efficient, and mild synthetic procedure has been developed for the synthesis of novel series of 1,3,4-oxadiazole containing azaspirocycles derivatives. The reaction of 1,3,4-oxadiazole derivative with diverse azaspiro compounds under room temperature condition with helps of sodium iodide catalyst and polar aprotic solvent. Numerous compensations of this strategy embrace less time required, yield increment, consumption of all reactants, and mild condition. All synthesized compounds evaluated for in vitro antidiabetic and antibacterial screening. Among them some compounds show significant biological response. 相似文献
In the present work, a controlled growth of ZnO nanostructures by manipulating Zn metal ion concentration by the chelating action of ethylene diaminetetra acetic acid in hydrothermal method is studied. EDTA produces metal–chelate complex by the formation of bidentate ligand with Zn2+ in the solution and diminishes the reactivity of Zn metal cations. Concentration of EDTA in the mother solution was varied in different ranges like 3, 5 and 10 mM while retaining the zinc metal salt and the NaOH concentration the same. Three different morphologies of wurtzite structured ZnO nanostructures such as nanorods-bunch, separate/discrete uniformly sized hexagonal nanorods and tapered flower petals like shapes are achieved by 3, 5 and 10 mM strengths of EDTA, respectively. The medium concentration 5 mM of EDTA is found to have moderate control over producing ZnO nanostructures of uniform diameter and a high aspect (length to diameter) ratio. An array of vertically aligned free standing ZnO nanorods with uniform spacing is successfully achieved by the addition of 5 mM of EDTA in the mother solution and the same is studied for its fluorescence property at an excitation of 325 nm and it has exhibited a characteristic UV emission of ZnO around 383 nm. 相似文献
In present investigation MnO2 thin films have been prepared by potentiodynamic (PD), potentiostatic (PS) and galvanostatic (GS) modes of electrodeposition. The effects of different modes on structural, surface morphological and supercapacitive properties of MnO2 thin films have been investigated. Formation of amorphous phase of MnO2 by all three modes is confirmed from X-ray diffraction (XRD) patterns. Significant change in the surface morphologies of MnO2 thin films due to different modes has been observed. The supercapacitive properties of MnO2 thin films have been studied in 1 M Na2SO4 electrolyte. The maximum supercapacitance obtained for potentiodynamic, potentiostatic and galvanostatic modes is 237, 196 and 184 F g−1, respectively. Additionally charge-discharge and impedance of MnO2 thin films have been investigated. 相似文献
Here, we present the effect of different Zn contents on the structural, morphological, and optical properties of CdXZn1-XS thin films deposited by electrodeposition method on stainless steel and indium-doped tin oxide (ITO) glass substrates. Electrosynthesized CdXZn1-XS thin films are characterized by using X-ray diffraction (XRD), UV-Vis spectrophotometer, field emission scanning electron microscope (FE-SEM), and surface wettability analysis. XRD pattern reveals that the CdXZn1-XS thin films are polycrystalline in nature with hexagonal crystal structure. FE-SEM micrograph displays that these CdXZn1-XS thin films exhibit the different sizes of sphere-like nanostructures by varying the X value. The optical absorption study indicates that drastic variation in band gap energy of CdXZn1-XS thin films. In advance photovoltaic measurements, CdXZn1-XS thin films are to be studied by forming the photoelectrochemical (PEC) cell having CdXZn1-XS/0.5 M (Na2SO3)/C configuration. The efficiency values of CdXZn1-XS are found to be 0.2, 0.35, 0.32, 0.25, and 0.23 % respectively at X content.
What is new in the field of neutrino detection? In addition to new projects probing both the low and high ends of the neutrino energy scale, an inexpensive, effective technique is being developed to allow tagging of antineutrinos in water Cherenkov (WC) detectors via the addition to water of a solute with a large neutron cross-section and energetic γ daughters. Gadolinium is an excellent candidate since in recent years it has become very inexpensive, now less than $8 per kilogram in the form of commercially available gadolinium trichloride. This non-toxic, non-reactive substance is highly soluble in water. Neutron capture on gadolinium yields an 8.0 MeV gamma cascade easily seen in detectors like Super-Kamiokande. The uses of GdCl3 as a possible upgrade for the Super-Kamiokande detector — with a view toward improving its performance as an antineutrino detector for supernova neutrinos and reactor neutrinos — are discussed, as are the ongoing R&;D efforts which aim to make this dream a reality within the next two years. 相似文献
Mn3O4 thin films have been prepared by novel chemical successive ionic layer adsorption and reaction (SILAR) method. Further these films were characterized for their structural, morphological and optical properties by means of X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), field emission scanning electron microscopy (FESEM), wettability test and optical absorption studies. The XRD pattern showed that the Mn3O4 films exhibit tetragonal hausmannite structure. Formation of manganese oxide compound was confirmed from FTIR studies. The optical absorption showed existence of direct optical band gap of energy 2.30 eV. Mn3O4 film surface showed hydrophilic nature with water contact angle of 55°. The supercapacitive properties of Mn3O4 thin film investigated in 1 M Na2SO4 electrolyte showed maximum supercapacitance of 314 F g−1 at scan rate 5 mV s−1. 相似文献