Field emission studies of WO2.72 nanowires synthesized by a solvothermal method have been performed in the planar diode configuration under ultra high vacuum
conditions. Fowler–Nordheim plots obtained from the current-voltage characteristics follow the quantum mechanical tunneling
process and a current density of ∼8.3×106 μA/cm2 can be drawn at an applied electric field of 2 V/μm. The field enhancement factor is 33025, while the turn-on field is only
1.4 V/μm. The emission current-time plot recorded at the pre-set value of emission current of 1 μA over a period of more than
3 h exhibits an initial increase and a subsequent stabilization of the emission current. The results reveal that the WO2.72 nanowire emitters synthesized by the solvothermal method are promising cathode materials for practical applications. 相似文献
Summary: In this work, an attempt was made to synthesize a novel Chitosan-Mesoporous silica (CS-MS) hybrid composite to design a drug delivery system based on ultrasound triggered stimuli-responsive smart release. The in-vitro drug release properties of both the Mesoporous Silica (MS) and Chitosan (CS) hybrids were investigated. Ibuprofen (Ibu) was used as a model drug. The results from powder X-Ray diffraction (XRD) patterns, and BET N2 adsorption isotherms exhibited that MS can accommodate drug molecules into the lumen of the channels and pores. Drug release, stimulated by temperature and pH of the release media was also investigated. We studied the Ultrasound (US) triggered release of Ibu in a simulated body fluid (pH 7.4). The results exhibited that US can be used as a non-invasive technique for drug release from polymeric materials. The enhancing effect of ultrasound on drug release is due to the Cavitation effect, without causing any significant destruction on the polymer morphology. 相似文献
Flame propagation of aluminum–ice (ALICE) mixtures is studied theoretically and experimentally. Both a mono distribution of nano aluminum particles and a bimodal distribution of nano- and micron-sized aluminum particles are considered over a pressure range of 1–10 MPa. A multi-zone theoretical framework is established to predict the burning rate and temperature distribution by solving the energy equation in each zone and matching the temperature and heat flux at the interfacial boundaries. The burning rates are measured experimentally by burning aluminum–ice strands in a constant-volume vessel. For stoichiometric ALICE mixtures with 80 nm particles, the burning rate shows a pressure dependence of rb = aPn, with an exponent of 0.33. If a portion of 80 nm particles is replaced with 5 and 20 μm particles, the burning rate is not significantly affected for a loading density up to 15–25% and decreases significantly beyond this value. The flame thickness of a bimodal-particle mixture is greater than its counterpart of a mono-dispersed particle mixture. The theoretical and experimental results support the hypothesis that the combustion of aluminum–ice mixtures is controlled by diffusion processes across the oxide layers of particles. 相似文献
The heat transfer performance and entropy analysis are done in a compact loop heat pipe (CLHP) with Al2O3/water and Ag/water nanofluid. A compact loop heat pipe having a flat square evaporator with dimensions of 34 mm (L)?×?34 mm (W)?×?19 mm (H) has been fabricated and tested for the heat load ranging from 30 to 500 W. The experimental tests are conducted by keeping the CLHP in the vertical orientation with distilled water, silver (Ag)/water and aluminium oxide (Al2O3)/water nanofluid having low volume concentrations of (0.09% and 0.12%). The effect of wall and vapour temperature, evaporator and condenser heat transfer coefficient, thermal resistance on the applied heat loads is experimentally investigated and compared. The experimental results showed that the evaporator thermal resistance is reduced by 34.70% and 20.21%, respectively, for 0.12 vol% of Ag, Al2O3 nanoparticles when compared with that of the distilled water. For the same volume concentrations of Ag, Al2O3 nanoparticles, an enhancement of 34.52%, 23.7%, 39.27% and 30.8%, respectively, observed for the convective heat transfer coefficients at the evaporator and condenser. The entropy is also reduced by 19.08% and 11.58% when Ag and Al2O3 nanofluids are used as the operating fluid. From the experimental tests, it is found that the addition of small amount of Ag nanoparticles in the working fluid enhanced the operating range by 15% when compared with that of Al2O3/water nanofluid without the occurrence of any dry-out conditions.
Recently Georgi has discussed the possible existence of ‘Unparticles’ describable by operators having non-integral scaling dimensions. With the interaction of these with the Standard Model particles being constrained only by gauge and Lorentz symmetries, it affords a new source for lepton flavour violation. Current and future muon decay experiments are shown to be very sensitive to such scenarios. 相似文献
To circumvent costly fluorescent labeling, five nonconventional, multifunctional, intrinsically fluorescent aliphatic terpolymers ( 1 – 5 ) have been synthesized by C−C/C−N-coupled, solution polymerization of two non-emissive monomers with protrusions of fluorophore monomers generated in situ. These scalable terpolymers were suitable for sensing and high-performance exclusion of CuII, logic function, and bioimaging. The structures of the terpolymers, in situ attachment of fluorescent monomers, aggregation-induced enhanced emission, bioimaging ability, and super adsorption were investigated by 1H and 13C NMR, EPR, FTIR, X-ray photoelectron, UV/Vis, and atomic absorption spectroscopy, thermogravimetric analysis, high-resolution transmission electron microscopy, dynamic light scattering, solid-state fluorescence, fluorescence imaging, and fluorescence lifetime measurements, as well as by isotherm, kinetics, and thermodynamic studies. The geometries and electronic structures of the fluorophores and the absorption and emission properties of the terpolymers were examined by DFT, time-dependent DFT, and natural transition orbital analyses. For 1 , 2 , and 5 , the limits of detection were determined to be 1.03×10−7, 1.65×10−7, and 1.77×10−7 m , respectively, and the maximum adsorption capacities are 1575.21, 1433.70, and 1472.21 mg g−1, respectively. 相似文献
Research on Chemical Intermediates - In the present study, the synthesis of ligand 6-chloro-5-7-dimethyl-4oxo-4H-chromene-3-carbaldehydes by three steps from the substituted phenol. The formed... 相似文献
Herein, we report the synthesis of fluorescent 1,4-dihydropyridine-linked bis-triazoles (2a–2n) through Hantzsch synthesis by the condensation of o/m-chloro-substituted benzaldehyde, ethyl 3-oxo-4(prop-2-yn-1-yloxy)butanoate, and ammonium acetate in the presence of Ba(NO3)2 as a catalyst followed by the click reaction of resultant Hantzsch product (1) with various aromatic as well as aliphatic azides. All the synthesized compounds were well characterized by 1H-NMR, 13C-NMR, FTIR, and HRMS spectral techniques. Antibreast cancer evaluation of all the synthesized derivatives revealed that the compounds 2f (IC50?=?7?±?0.02?µM) and 2g (IC50?=?5?±?0.03?µM) showed better anticancer activity (lower IC50) than the standard drug tamoxifen (IC50?=?11.2?±?0.01?µM) against breast carcinoma (MDA-MB-231) cell line. The synthesized compounds were also screened against normal human embryonic kidney (HEK-293) cell line and found to be nontoxic. The fluorescent nature and cytotoxicity assay of these newly synthesized hybrids recommend their utility in tumor cell imaging. 相似文献
Spectroscopic investigation of a dihydrogen-bonded complex between phenol and triethylgermanium hydride is reported here. Laser-induced fluorescence excitation, fluorescence-detected infrared, and IR-UV hole-burning spectroscopic studies were carried out in supersonic jet to investigate the complex formation between phenol and triethylgermanium hydride. The lowering of the O-H stretching frequency of the phenol moiety in the complex with triethylgermanium hydride clearly establishes the role of phenol as hydrogen bond donor. The experimental results together with the ab-initio calculations unambiguously confirm formation of an O-H...H-Ge dihydrogen-bonded complex between phenol and triethylgermanium hydride. 相似文献