In this letter the advantages of the overlapping-gate buried-channel charged-coupled devices over the 3-phase metal-gate and resistive-gate buried-channel c.c.d. are discussed and pertinent design considerations for the overlapping-gate c.c.d.s are presented. 相似文献
Surface currents induced on imperfectly conducting objects are obtained from the surface current of a perfectly conducting object using the impedance boundary conditions on its surface. The resulting errors in computation of these surface currents are determined and are shown to depend on the excitation source. 相似文献
The influence of codoping of Fe, Co, Ni, Cu as acceptors and F as donor on the dielectric properties of screen-printed Ba0.6Sr0.4TiO3 ceramic thick-films has been investigated. The undoped and codoped Ba0.6Sr0.4TiO3 powders were synthesized through a sol-gel route. The thermal gravimetric analysis revealed the difference of the thermal
decomposition behaviour between the undoped and codoped precursors. The ceramic powders were characterized with x-ray diffraction,
scanning electron microscopy and BET measurements. Larger crystallite sizes of the codoped powders were observed. The densification
behaviour of the powders was recorded by dilatometry and indicated that codoping influences the sintering mechanism. The permittivity,
dielectric loss and tunability of the undoped and codoped thick-films were characterized with coplanar waveguide structures
up to 30 GHz. 相似文献
A new soluble organic–inorganic hybrid based on polyoxomolybdate, [C6H12N5O]3[(PO4)Mo12O36]·6H2O (1), has been successfully synthesized and characterized by using elemental analysis, IR, UV spectroscopies, 1H NMR technique, and single-crystal X-ray diffraction. According to the results of X-ray crystallography the anion [(PO4)Mo12O36]3− has a typical Keggin structure and the Mo–O distances of Mo–O–Mo bonds are alternately short and long in the polyoxoanion structure. Hirshfeld surface analyses, especially dnorm surface and fingerprint plots, are used for decoding intermolecular interactions in the crystal network and contribution of component units for the construction of the 3D architecture. The results indicate that in 1 the hydrogen bond interaction play a main role in the construction of the 3D architecture, especially the CHO interaction which overruns the classic NHO, NHO hydrogen bond interactions; van der Waals force between the peripheral atoms of component units cannot be ignored. 相似文献
In this study, a preformed particle gel (PPG) was synthesized from sulfonated polyacrylamide and chromium metal cross-linker with specific concentration. The main characteristics of PPG, such as gelation time, gel fraction, swelling properties and salt sensitivity factor were investigated. The gel fraction of 94.1% practically indicated an appropriate conversion of gelant to the gel. The equilibrium swelling ratios of particle gels in distilled water and formation water at 80 °C were 470.49 and 12.61, respectively. Additionally, the rheological properties of gel were studied by a dynamic rheometer. The ultimate storage modulus of gel was measured 35.4 kPa. The linear viscoelastic behavior was observed at strain between 1 and 82.6% and gel structure was stable up to strain of 1120% with small reduction of storage modulus. The kinetics of gelation were also studied at different temperatures and tested against Avrami equation to determine the kinetic parameters. The Avrami exponents for two kinetic steps were about 2.29 and 0.80, respectively, indicating the rapid formation of the gel network at first step due to nucleation and two-dimensional growths of gel nuclei. Furthermore, a core flooding experiment was conducted to study PPG performance in porous media. The residual resistance factor of water and oil was 41.58 and 12.91, respectively. A value of 3.22 for the ratio of these two factors indicated the ability of the synthesized PPG to decrease water-effective permeability compared to oil-effective permeability in porous media.
Thermochromic VO2 thin films were deposited on soda-lime glass via sol-gel method. Doping was done through adding tungstic acid solution to the vanadium solution precursor. Grazing incidence x-ray diffractometer (GIXRD) results showed that VO2 and V6O13 phases were formed together in the heat-treated sample. According to the GIXRD result of the W-doped sample, only VO2 remained. Field-emission scanning electron microscopy (FESEM) micrographs showed that the VO2 grain size decreased from about 70 to about 25 nm for undoped film and 2 wt% W-doped films, respectively. Atomic force microscopy (AFM) results showed that the root mean square roughness for the film with 180 nm thickness was about 18 nm, and 2 wt% W-doped film had a smoother surface. Diffuse reflectance spectroscopy (DRS) results showed that the band gap energy for undoped, 1 wt% W- doped, and 2 wt% W-doped VO2 thin films was 1.7, 1.3, and 0 eV, respectively. Four-point probe resistivity measurements showed a significant decrement, from approximately 1 MΩ at 15°C to <100 Ω at 80°C. Regarding Vis-NIR spectroscopy results, maximum optical transmission for undoped and W-doped films was approximately 75% and 35%, respectively. 相似文献