查看更多>>摘要：Aluminum nitride films were prepared by mid-frequency magnetron sputtering on Si (111)substrate. The grown films were characterized by X-ray diffraction(XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy(XPS) to obtain the structural and the chemical information. The polycrystalline thin films were in a hexagonal wurtzite structure having a (002) preferred orientation, along which the columnar grain structure was found. XPS study revealed the presence of oxygen and carbon contaminations, as well as the Al-rich nature of the film. Anomalous C-V characteristics of Al/AIN/n-Si capacitors were studied. The measured C-V curves show rolloffs in the accumulation region and voltage stresses cause both horizontal and vertical shifts of the C-V curves. These anomalous behaviors are mainly due to the large current conduction and the charge trapping in the Al-rich AlN layer.
查看更多>>摘要：SnS: Ag thin films were deposited on ITO glasses by pulse electro-deposition. By studying the effect of duty cycle on the properties of SnS: Ag thin films, the optimum off-time(toff) is obtained to be 5 s,namely, the optimal duty cycle is about 67%. The primary phase of SnS: Ag films deposited on optimum parameters condition is SnS compound with good crystallization, and the films prefer to grow towards (111)plane. The films are dense, smooth and uniform with good microstructure, and the grains in the films are densely packed together, and their direct bandgap is about 1.40 eV.In addition, the bandgap of the films first rises and then drops with the increase of the duty cycle.
查看更多>>摘要：Structural un-uniforrnity and electrical anisotropy of μc-Si: H film are investigated in this paper.It is found that the structure of μc-Si: H film along the direction perpendicular to the substrate is not uniform,which is modulated by film thickness. In addition, there is a dark conductivity anisotropy along the direction parallel(σ//) and perpendicular(σ⊥)to the substrate in μc-Si: H film. The reasons for such an property of μc-Si: H film and the effect of oxygen contamination are analyzed.
查看更多>>摘要：In this paper, the lattice parameter and bulk modulus of lithium(Li) at different pressures and temperatures are calculated by using the density functional theory method within the generalized gradient approximation(GGA). Through the quasi-harmonic Debye model, the thermodynamic properties of Li are predicted. The dependences of the normalized primitive cell volume V/V0 on pressure P, the variation of the thermal expansion coefficient α with pressure P and temperature T, as well as the dependences of the heat capacity Cv on pressure P and temperature T. are obtained systematically in the ranges of 0～100 GPa and 0～2000 K.
查看更多>>摘要：In this paper, the reflective spectra of a refraction index sensor were analyzed based on fiber grating F-P cavity. The sensor was constituted by two identical fiber gratings. Compared with the refraction index sensor using one fiber grating, the fiber grating F-P cavity sensor has narrower resonant peak and it can be used for more accurate measurement. The resonant peaks in the reflective spectra of the sensor are changed with small changes of the refraction index of the measured chemical liquids or cell samples. So it has potential applications in biology and chemistry.
查看更多>>摘要：The design of a large-aperture and wide-band optical lens for camera is presented. By utilizing the atmospheric window of infrared light, clear images can be achieved in the dark or poor visibility conditions. To use near-infrared and visible light to obtain images, the charge coupled device(CCD) is adopted as the image sensor of the lens with the center wavelength of 880 nm, which operates at the wavelength range from 400 nm to 1 000 nm. After calculating the parameters of optical lens, Sunnah type is selected as the initial structure. Through the optimization of optical design software ZEMAX, the lens obtains an excellent imaging performance. The modulation transfer function(MTF) can be more than 0. 3 at the spatial frequency of 110 lp/ mm, and the maximum distortion can be less than 0. 1%.
查看更多>>摘要：In this paper,a simulation model of bistable system subject to multiplicative and additive noise is built on the basis of the theory of stochastic resonance(SR).SR phenomenon appears in the system subject to multiplicative and additive noise when a single signal transmits in the system.The output waveforms and the power spectrums at different frequencies are compared.The impact of the intensity of multiplicative and additive noise on the bistable system is discussed.It is found that this simulation model can upgrade the quality of the signal processing and the noise intensity can be effectively used for improving the effect of SR.
查看更多>>摘要：The compound 1,6: 3,4-Bis(1,2-xylyiene)tetrahydro-imidazo[4,5-d]imidazole-2,5(1H,3H)-dione(C20 H18 N4O2,Mr = 346.38)has been synthesized for the first time.Complete assignments were achieved by 1H NMR,IR,EI-MS,elemental analysis and single-crystal X-ray diffraction technique.The crystal belongs to monoclinic,space group P2(1)/n with a = 10.266 0(16),b= 11.298 5(18),c= 1.452 20(20)nm,β=97.923(3),V=1.668 4(5)nm3,Z=4,Dc=1.379 g/cm3,/μ(MoKa)=0.092 mm-1,F(000)=728,R=0.053 2 and ωR=O.112 3 for 3632 observed reflections with I>2σ(I).X-ray analysis reveals dimeric aggregates are formed through hydrogen bond and offset π-π stacking.In addition,the compound assembles to a three-dimensional networking structure by other hydrogen bond.
查看更多>>摘要：The dynamic system control circuit board(DSCCB)is one of the most important components for dynamic system of pure electric vehicles.The current detection of the DSCCB is done manually,which is not only inefficient in the detection but also difficult to guarantee the data accuracy.In order to improve the detection efficiency and accuracy,a new testing system is designed by Labview.The total test time can be further reduced by about 75% compared with the results of the manual detection.In this paper,the threeparameter sine wave curve-fit algorithm theory is applied to the phase delay detection of the current sensor sampling circuit on the DSCCB.This method solves the problem of big error in the phase delay detection.
查看更多>>摘要：The compound 1,6:3,4-Bis(4,5-dimethyl)tetrahydrc3a,6adiphenylimidazo[4,5-d]imidazole-2,5(1H,3H)-dione(CO H40 Cl0.33 N4 O10,Mr=748.58)has been synthesized for the first time.Complete assignments were achieved by using 1H NMR,IR,EI-MS,elemental analysis and single-crystal X-ray diffraction technique.The crystal belongs to Orthorhombic,space group C 2/c with a=29.280(4),b=11.8617(16),c=1.9212(3)nm,β=91.240(3),V=6.6707(16)nm3,Z=6,Dc=1.118 g/cm3,p(MoKa)=0.092mm-1,F(000)=3 146,R=O.0670 and wR=O.187 9 for 6551 observed reflections with I>2σ(I).X-ray analysis reveals that dimeric aggregates are formed through C-H…π interactions and and offset π-π stacking.In addition,the compound assembles to a threedimensional network.ing structure by other hydrogen bond.
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