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131.
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133.
Frequency and voltage-dependent electrical and dielectric properties of Al/Co-doped PVA/p-Si structures at room temperature
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In order to investigate of cobalt-doped interracial polyvinyl alcohol (PVA) layer and interface trap (Dit) effects, A1/p- Si Schottky barrier diodes (SBDs) are fabricated, and their electrical and dielectric properties are investigated at room temperature. The forward and reverse admittance measurements are carded out in the frequency and voltage ranges of 30 kHz-300 kHz and -5 V-6 V, respectively. C-V or er-V plots exhibit two distinct peaks corresponding to inversion and accumulation regions. The first peak is attributed to the existence of Dit, the other to the series resistance (Rs), and interfacial layer. Both the real and imaginary parts of dielectric constant (er and err) and electric modulus (Mr and Mrr), loss tangent (tan~), and AC electrical conductivity (aac) are investigated, each as a function of frequency and applied bias voltage. Each of the M~ versus V and Mrr versus V plots shows a peak and the magnitude of peak increases with the increasing of frequency. Especially due to the Dit and interfacial PVA layer, both capacitance (C) and conductance (G/w) values are strongly affected, which consequently contributes to deviation from both the electrical and dielectric properties of A1/Co-doped PVA/p-Si (MPS) type SBD. In addition, the voltage-dependent profile of Dit is obtained from the low-high frequency capacitance (CLF-CHF) method. 相似文献
134.
This paper presents the influence of a concentrated mass location on the natural frequencies of a cracked double-beam. The double-beam consists of two different beams connected by an elastic medium. The concentrated mass is located on the main beam. The relationship between the natural frequency and the location of concentrated mass is established and called “Frequency–Mass Location” (FML). The numerical simulations show that when there is a crack, the frequency of the double-beam changes irregularly when the concentrated mass is attacked at the crack position. This irregular change can be amplified by the wavelet transform and this is useful for crack detection: the crack location can be detected by the location of peaks in the wavelet transform of the FML. Finite element model for the cracked double-beam carrying a concentrated mass is presented and numerical simulations are also provided. 相似文献
135.
A dual hesitant fuzzy set (DHFS) consists of two parts, that is, the membership hesitancy function and the nonmembership hesitancy function, supporting a more exemplary and flexible access to assign values for each element in the domain, and can handle two kinds of hesitancy in this situation. It can be considered as a powerful tool to express uncertain information in the process of group decision making. Therefore, we propose a correlation coefficient between DHFSs as a new extension of existing correlation coefficients for hesitant fuzzy sets and intuitionistic fuzzy sets and apply it to multiple attribute decision making under dual hesitant fuzzy environments. Through the weighted correlation coefficient between each alternative and the ideal alternative, the ranking order of all alternatives can be determined and the best alternative can be easily identified as well. Finally, a practical example of investment alternatives is given to demonstrate the practicality and effectiveness of the developed approach. 相似文献
136.
This letter presents a new method for continuous signal modeling. Firstly, the continuous signal can be represented as a function of the trigonometric functional extension (Fourier series). Fourier series of the signal are parameterized by the fundamental frequency and unknown parameters. Then, the gradient-based iterative identification algorithm is derived, for estimating parameters of the signal model with known and unknown frequencies, separately. Finally, the simulation results indicate that the proposed algorithm is effective. 相似文献
137.
Xia Li Gang-Hua Deng Rong-Juan Feng Ke Lin Zhen Zhang Yu Ba Zhou Lu Yuan Guo 《中国化学快报》2016,27(4):535-539
The salt effects on molecular orientation at air/liquid methanol interface were investigated by the polarization-dependent sum frequency generation vibrational spectroscopy(SFG-VS). We clarified that the average tilting angle of the methyl group to be u = 308 58 at the air/pure methanol surface assuming a d-function orientational distribution. Upon the addition of 3 mol/L Na I, the methyl group tilts further away from the surface normal with a new u = 418 38. This orientational change does not explain the enhancement of the SFG-VS intensities when adding Na I, implying the number density of the methanol molecules with a net polar ordering in the surface region also changed with the Na I concentrations. These spectroscopic findings shed new light on the salt effects on the surfaces structures of the polar organic solutions. It was also shown that the accurate determination of the bulk refractive indices and Raman depolarization ratios for different salt concentrations is crucial to quantitatively interpret the SFG-VS data. 相似文献
138.
《中国化学快报》2021,32(9):2869-2872
Pressure-related sensing materials in mechanochromic luminescent materials have received wide attention. However, at present, most piezochromic luminescence (PCL) materials have problems such as aggregation-caused quenching (ACQ) effect due to the presence of powder form, complicated preparation methods and fluorescence quenching effect under high pressure. To solve these problems, we employ three components containing carbon dots (CDs), layered double hydroxides (LDHs) and polyvinyl alcohol (PVA) to construct the CDs-LDHs/PVA film. The LDHs can provide a rigid environment for CDs and improve the luminescent efficiency of CDs. The film shows high sensitivity, stability and reversibility. Moreover, the compressed film can recover to its original state by heating. Therefore, the PCL film with dual emission (fluorescence and phosphorescence) characteristic is constructed, which boosts the sensitivity of pressure-sensing. 相似文献
139.
In the paper comparison of accuracy of two methods used for investigations of hydrodynamic in continuous flow tanks has been made. Basis for the comparison is the experimental work performed for big industrial wastewater concentration equalization tank. The first method is based on the radiotracer experiment while the second one uses the analysis of response on sudden change of the technological parameters. The radiotracer method has better accuracy connected with the shorter sampling period. Ks wird die Genauigkeit zweier Methoden zur Untersuchting der Hydrodynamik von kontinuierlich arbeitenden Flüssigkeitsbehältern verglichen. Grundlage dafür sind experimentelle Untersuchungen an groβen Industrieabwasser-Ausgleichsbehältern. Die erste Methode bedient sich der Radiotracertechnik, während die zweite Methode auf einer plötzlichen Veränderung der technologischcn Parameter beruht. Es zeigt sich, daβ die Radiotracermethoden die besseren Ergebnisse liefert, wobei auβerdem noch kürzere Probenaltmeperioden von Vorteil sind. 相似文献
140.
Comparison of the effects of K4Fe(CN)6 and K3Fe(CN)6 on TICT dual fluorescence of sodium p-dimethylaminobenzoate (SDMAB) in cetyltrimethyl ammonium chloride (CTAC) micelle yields a conclusion that the presence of a magnetic effect un favors the TICT process, which is verified by inserting the sample in a stationary magnetic field of 100G in which a decrease in the relative quantum yield of TICT state is observed. 相似文献