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RC-Circuit-Like Dynamic Characteristic of the Magnetic Domain Wall in Flat Ferromagnetic Nanowires
CHEN Cheng, PIAO Hong-Guang, SHIM Je-Ho, PAN Li-Qing, KIM Dong-Hyun
Chin. Phys. Lett.    2015, 32 (08): 087502.   DOI: 10.1088/0256-307X/32/8/087502
Abstract   PDF (807KB)
We investigate the dynamic behavior of the magnetic domain wall under perpendicular magnetic field pulses in flat ferromagnetic nanowires using micromagnetic simulations. It is found that the perpendicular magnetic field pulse can trigger the magnetic domain wall motion, where all the field torques are kept on the plane of nanowire strip. The speed of magnetic domain walls faster than several hundreds of meters per second is predicted without the Walker breakdown for the perpendicular magnetic driving field stronger than 200 mT. Interestingly, the dynamic behavior of the moving magnetic domain wall driven by perpendicular magnetic field pulses is explained by charging- and discharging-like behaviors of an electrical RC-circuit model, where the charging and the discharging of magnetic charges on the nanowire planes are considered. The concept of the RC-model-like dynamic characteristic of the magnetic domain wall might be promising for the applications in spintronic functional devices based on the magnetic domain wall motion.
Topology Identification of General Dynamical Network with Distributed Time Delays
WU Zhao-Yan, FU Xin-Chu
Chin. Phys. Lett.    2009, 26 (7): 070201.   DOI: 10.1088/0256-307X/26/7/070201
Abstract   PDF (336KB)
General dynamical networks with distributed time delays are studied. The topology of the networks are viewed as unknown parameters, which need to be identified. Some auxiliary systems (also called the network estimators) are designed to achieve this goal. Both linear feedback control and adaptive strategy are applied in designing these network estimators. Based on linear matrix inequalities and the Lyapunov function method, the sufficient condition for the achievement of topology identification is obtained. This method can also better monitor the switching topology of dynamical networks. Illustrative examples are provided to show the effectiveness of this method.
Quantum Illumination with Noiseless Linear Amplifier
ZHANG Sheng-Li, WANG-Kun, GUO Jian-Sheng, SHI Jian-Hong
Chin. Phys. Lett.    2015, 32 (09): 090301.   DOI: 10.1088/0256-307X/32/9/090301
Abstract   PDF (602KB)
Quantum illumination, that is, quantum target detection, is to detect the potential target with two-mode quantum entangled state. For a given transmitted energy, the quantum illumination can achieve a target-detection probability of error much lower than the illumination scheme without entanglement. We investigate the usefulness of noiseless linear amplification (NLA) for quantum illumination. Our result shows that NLA can help to substantially reduce the number of quantum entangled states collected for joint measurement of multi-copy quantum state. Our analysis on the NLA-assisted scheme could help to develop more efficient schemes for quantum illumination.
Two Typical Discontinuous Transitions Observed in a Generalized Achlioptas Percolation Process
HU Jian-Quan, YANG Hong-Chun, YANG Yu-Ming, FU Chuan-Ji, YANG Chun, SHI Xiao-Hong, JIA Xiao
Chin. Phys. Lett.    2014, 31 (07): 078901.   DOI: 10.1088/0256-307X/31/7/078901
Abstract   PDF (1133KB)
We extend the Achlioptas percolation (AP) process [Achlioptas et al. Science 323 (2009) 1453] to two generalized Achlioptas percolation processes named GAP1 and GAP2. GAP1 induces a weighted probability factor α in the node sampling process and excludes the intracluster links. Based on GAP1, GAP2 requires m pairs of nodes sampled to add m candidate links that should be residing in 2m different clusters at each step. In the evolution of GAP1, the phase transition can evolve from the continuous to the 'most explosive' percolation as the value of the factor α is decreasing to a certain negative number. It indicates that there might be a type of discontinuous transition induced by the probability modulation effect even in the thermodynamic limit, and the most explosive percolation is only one of its extreme cases. We analyze the characteristics of the evolving process of the two-nodes-clusters and the cluster-size distribution at the transformation point for different α; the numerical results suggest that there might be a critical value α0 and the phase transition should be discontinuous (αα0) or continuous (α>α0). In the evolution of GAP2, twice phase transitions are observed successively and the time duration between them becomes shorter till they amalgamate into the 'most explosive' percolation. The first transition is induced by the probability modulation effect analyzed in GAP1, the second transition, induced by the three coexisting giant clusters, is always discontinuous and the maximum jump of order parameter approaches N/3 while the value of the factor α is increasing to 1.4 approximately. In this work, two typical discontinuous transitions induced respectively by the probability modulation and the extended local competition are exhibited in GAP2, which might provide references to analyze the discontinuous phase transition in networks further.
Spectral Study of Effects of Aluminium Nanoparticles on Fast Reaction of Nitromethane
WU Jing-He, YE Song, HU Dong, YANG Xiang-Dong
Chin. Phys. Lett.    2008, 25 (3): 1138-1141.  
Abstract   PDF (1236KB)
Fast reactions between nitromethane and aluminium nanoparticles are studied using transient spectral methods. In comparison with species produced by pure nitromethane, the emergence time for species produced by nitromethane after addition of 1g of aluminium nanoparticles decreases by 46-58% and the emission intensity increases by 13-100%. The results demonstrate that aluminium nanoparticles have positive effect on accelerating the decomposition rate of nitromethane and that the explosion efficiency of nitromethane is greatly improved. Fast reactions carried out between nitromethane and aluminium nanoparticles in different environments (CO2, H2O and O2) reveal that O2 and an appropriate amount of H2O improve the explosion efficiency of nitromethane, whereas CO2 has the weakest effect on improving this parameter. The investigations provide insights into the process
occurring in actual systems involving propellants and fuel--air explosives.
Diode Laser Optically Injected by Resonance of a Monolithic Cavity
PENG Yu, **, ZHAO Yang, LI Ye, YANG Tao, CAO Jian-Ping, FANG Zhan-Jun, ZANG Er-Jun
Chin. Phys. Lett.    2011, 28 (11): 114208.   DOI: 10.1088/0256-307X/28/11/114208
Abstract   PDF (673KB)
We demonstrate a self-injection locking extended cavity diode laser (ECDL) using resonant optical feedback from the p-polarization of a monolithic folded Fabry–Perot parallel cavity (MFC). The full width at half maximum of the MFC resonance is 31 MHz. With the help of a narrow-linewidth reference laser, the linewidth of the ECDL is measured to be about 7 kHz. The frequency of the laser could be tuned at 160 MHz with an amplitude of 40 V by a PZT mounted on the monolithic cavity and the voltage tuning coefficient is about 4 MHz/V.
Proposed Test of the Equivalence Principle with Rotating Cold Polar Molecules
HU Zhong-Kun, KE Yi, DENG Xiao-Bing, ZHOU Ze-Bing, and LUO Jun
Chin. Phys. Lett.    2012, 29 (8): 080401.   DOI: 10.1088/0256-307X/29/8/080401
Abstract   PDF (602KB)
We propose a novel scheme for testing the equivalence principle with rotating cold polar molecules whose angular momenta are polarized at different states. Molecules in specific rotational states are selected out via the hexapole state-selection technique and the gravitational acceleration g of molecules is measured by measuring the Doppler shift of the molecules free falling in the gravitational field. Some other possible methods of rotating molecules and measuring g are also mentioned. Molecules, as the test masses, have higher rotating speed and smaller dimension in comparison with mechanical gyroscopes and may open a new way for testing the equivalence principle and the possible coupling between rotation and gravity.
Anomalous Temperature Dependence of the Quality Factor in a Superconducting Coplanar Waveguide Resonator
ZHOU Pin-Jia, WANG Yi-Wen, WEI Lian-Fu
Chin. Phys. Lett.    2014, 31 (06): 067402.   DOI: 10.1088/0256-307X/31/6/067402
Abstract   PDF (813KB)
We present the measurements of the temperature dependence of the internal quality factor (Qi) of a microwave resonator, well below the superconducting transition temperature. The device is a quarter-wavelength niobium (Tc=9.2 K) coplanar waveguide resonator. The measured |S21| parameter shows typically the skewed Lorentzian distributions, from which the fitted quality factor monotonically decreases with the temperature increasing from 30 mK to 900 mK. It is observed that for the lower temperature range (i.e., at T<700 mK) the temperature dependence of the fitted Qi deviates significantly from the predictions of the usual Mattis–Bardeen theory. The measured 3 dB internal quality factor Q'i also verifies such an anomalous temperature dependence. Physically, this phenomenon could be attributed dominantly to the effects of the two-level systems in the device, rather than the usual temperature-dependent complex conductance.
Low Bias Negative Differential Resistance with Large Peak-to-Valley Ratio in a BDC60 Junction
REN Hua, LIANG Wei, ZHAO Peng, LIU De-Sheng
Chin. Phys. Lett.    2012, 29 (7): 077301.   DOI: 10.1088/0256-307X/29/7/077301
Abstract   PDF (1575KB)
Based on nonequilibrium Green's function method and density functional theory calculations, we investigate theoretically the electronic transport properties of 1,4-bis(fullero[c]pyrrolidinl-yl)benzene (BDC60). A low bias negative differential resistance with the peak-to-valley ratio as high as 305.41 is obtained. The observed negative differential resistance is explained in terms of the evolution of the transmission spectra, molecular projected self-consistent Hamiltonian states and molecular projected energy levels with applied bias.
A Multifractal Detrended Fluctuation Analysis of the Ising Financial Markets Model with Small World Topology
ZHANG Ang-Hui, LI Xiao-Wen, SU Gui-Feng, ZHANG Yi
Chin. Phys. Lett.    2015, 32 (09): 090501.   DOI: 10.1088/0256-307X/32/9/090501
Abstract   PDF (929KB)

We present a multifractal detrended fluctuation analysis (MFDFA) of the time series of return generated by our recently-proposed Ising financial market model with underlying small world topology. The result of the MFDFA shows that there exists obvious multifractal scaling behavior in produced time series. We compare the MFDFA results for original time series with those for shuffled series, and find that its multifractal nature is due to two factors: broadness of probability density function of the series and different correlations in small- and large-scale fluctuations. This may provide new insight to the problem of the origin of multifractality in financial time series.

Simulation and Characterization of Aluminium Three-Dimensional Resonator for Quantum Computation
ZHAO Hu, LI Tie-Fu, LIU Qi-Chun, LIU Jian-She, CHEN Wei
Chin. Phys. Lett.    2014, 31 (10): 102101.   DOI: 10.1088/0256-307X/31/10/102101
Abstract   PDF (987KB)
We present the simulation and characterization of several aluminium three-dimensional (3D) resonators, which can be used for superconducting quantum computation. By changing the conductivity of the aluminium in a high frequency structure simulator, the loaded quality factor at room temperature and base temperature (20 mK) can be simulated. From S21 measurement, we can characterize the properties of the resonators. The simulated and experimental results can be fitted well by exponential equations.
Asymptotic Behavior of Periodic Wave Solution to the Hirota–Satsuma Equation
WU Yong-Qi
Chin. Phys. Lett.    2011, 28 (6): 060204.   DOI: 10.1088/0256-307X/28/6/060204
Abstract   PDF (462KB)
The one- and two-periodic wave solutions for the Hirota–Satsuma (HS) equation are presented by using the Hirota derivative and Riemann theta function. The rigorous proofs on asymptotic behaviors of these two solutions are given such that soliton solution can be obtained from the periodic wave solution in an appropriate limiting procedure.
A High-Precision Calculation of Bond Length and Spectroscopic Constants of Hg2 Based on the Coupled-Cluster Theory with Spin–Orbit Coupling
TU Zhe-Yan, WANG Wen-Liang
Chin. Phys. Lett.    2015, 32 (06): 063101.   DOI: 10.1088/0256-307X/32/6/063101
Abstract   PDF (434KB)
Based on the two-component relativistic effective core potential and matched basis sets cc-pwcvnz-pp (n=Q, 5), combining the completed basis-set extrapolation of electronic correlation energy and the fourth-order polynomial fitting technique, the bond length and spectroscopic constants of Hg2 are studied by the coupled cluster theory with spin–orbit coupling. Spin–orbit coupling is included in the post Hartree–Fock procedure, i.e., in the coupled-cluster iteration, to obtain more reliable theoretical results. The results show that our theoretical values agree with the experimental values very well and will be helpful to understand the spectral character of Hg2.
Analysis of Off-State Leakage Current Characteristics and Mechanisms of Nanoscale MOSFETs with a High-k Gate Dielectric
LIU Hong-Xia, MA Fei
Chin. Phys. Lett.    2012, 29 (12): 127301.   DOI: 10.1088/0256-307X/29/12/127301
Abstract   PDF (646KB)
The off-state leakage current characteristics of nanoscale channel metal-oxide-semiconductor field-effect transistors with a high-k gate dielectric are thoroughly investigated. The off-state leakage current can be divided into three components: the gate leakage current, the source leakage current, and the substrate leakage current. The influences of the fringing-induced barrier lowering effect and the drain-induced barrier lowering effect on each component are investigated separately. For nanoscale devices with high-k gates, the source leakage current becomes the major component of the off-state leakage current.
Nonlocal Symmetries and Geometric Integrability of Multi-Component Camassa–Holm and Hunter–Saxton Systems
YAN Lu, SONG Jun-Feng, QU Chang-Zheng**
Chin. Phys. Lett.    2011, 28 (5): 050204.   DOI: 10.1088/0256-307X/28/5/050204
Abstract   PDF (448KB)
We present the multi-component Hunter–Saxton and μ−Camassa–Holm systems. It is shown that the multi-component Camassa–Holm, Hunter–Saxton and μ-Camassa–Holm systems are geometrically integrable, namely they describe pseudo-spherical surfaces. As a consequence, their infinite number of conservation laws can be directly constructed. For the three-component Camassa–Holm and Hunter–Saxton systems, their nonlocal symmetries depending on the pseudo-potentials are obtained.
Fusion Reaction Rate Coefficient for Different Beam and Target Scenarios
OU Wei, ZENG Xian-Jun, DENG Bai-Quan, GOU Fu-Jun
Chin. Phys. Lett.    2015, 32 (02): 022801.   DOI: 10.1088/0256-307X/32/2/022801
Abstract   PDF (567KB)
Fusion power output is proportional not only to the fuel particle number densities participating in reaction but also to the fusion reaction rate coefficient (or reactivity), which is dependent on reactant velocity distribution functions. They are usually assumed to be dual Maxwellian distribution functions with the same temperature for thermal nuclear fusion circumstances. However, if high power neutral beam injection and minority ion species ICRF plasma heating, or multi-pinched plasma beam head-on collision, in a converging region are required and investigated in future large scale fusion reactors, then the fractions of the injected energetic fast ion tail resulting from ionization or charge exchange will be large enough and their contribution to the non-Maxwellian distribution functions is not negligible, hence to the fusion reaction rate coefficient or calculation of fusion power. In such cases, beam-target, and beam-beam reaction enhancement effect contributions should play very important roles. In this paper, several useful formulae to calculate the fusion reaction rate coefficient for different beam and target combination scenarios are derived in detail.
Characterization and Magnetic Properties of Nickel Ferrite Nanoparticles Prepared by Ball Milling Technique
G. Nabiyouni**, M. Jafari Fesharaki, M. Mozafari, J. Amighian
Chin. Phys. Lett.    2010, 27 (12): 126401.   DOI: 10.1088/0256-307X/27/12/126401
Abstract   PDF (676KB)
Nickel ferrite nanoparicles with various grain sizes are synthesized using annealing treatment followed by ball milling of its bulk component materials. Commercially available nickel and iron oxide powders are first mixed, and then annealed at 1100°C in an oxygen environment furnace and for 3 h. The samples are then milled for different times in an SPEX mill. X-ray diffraction pattern indicates that in this stage the sample is single phase. The average grain size is estimated by scanning electron microscopy (SEM) and x-ray diffraction techniques. Magnetic behavior of the sample at room temperature is studied using a superconducting quantum interference device (SQUID). The Curie temperature of the powders is measured by an LCR–meter unit. The x-ray diffraction patterns clearly indicate that increasing the milling time leads to a decrease in the grain size and consequently leads to a decrease in the saturation magnetization as well as the Curie temperatures. This result is attributed to the spin-glass-like surface layer on the nanocrystalline nickel ferrite with a ferrimagnetically aligned core.
Deterministic Secure Direct Communication by Using Swapping Quantum Entanglement and Local Unitary Operations
MAN Zhong-Xiao, ZHANG Zhan-Jun, LI Yong
Chin. Phys. Lett.    2005, 22 (1): 18-21.  
Abstract   PDF (323KB)
A deterministic direct quantum communication protocol is proposed by using swapping quantum entanglement and local unitary operations. The present protocol is secure for the proof of the security of the present scheme, the same as that in the two-step protocol [Phys. Rev. A 68(2003)042317]. Additionally, the advantages and disadvantages of the present protocol is also discussed.
High Power Er/Yb Codoped Double Clad Fiber Pulsed Amplifier Based on an All-Fiber Configuration
ZHOU Lei, NING Ji-Ping, CHEN Cheng, HAN Qun, ZHANG Wei-Yi, WANG Jun-Tao
Chin. Phys. Lett.    2009, 26 (6): 064215.   DOI: 10.1088/0256-307X/26/6/064215
Abstract   PDF (543KB)
We report an all-fiber two-stage high power pulsed amplifier, seeded with a 1550nm, 1kHz repetition rate rectangular pulse, and based on Er/Yb co-doped double clad fiber. All the characteristics are measured in the experiment. The maximal slope efficiency is 22.56%, which is the highest we know of at such a low repetition rate, and the maximal output signal power is 1W. The various factors that affect the pulsed amplifier performance are analyzed. A high output power while keeping high power conversion efficiency can be obtained with careful selection of the input power, pump power and repetition rate. The experimental results show that the crucial parameters should be optimized when designing all-fiber pulsed amplifiers.
Characterization of Undoped and Cu-Doped ZnO Thin Films Deposited on Glass Substrates by Spray Pyrolysis
Metin Bedir, Mustafa Ö, ztas, A. Necmeddin Yazici, E. Vural Kafadar
Chin. Phys. Lett.    2006, 23 (4): 939-942.  
Abstract   PDF (257KB)
Undoped and copper doped zinc oxide (ZnO) thin films have been prepared on glass substrates by spray pyrolysis technique. The films were doped with copper using the direct method by addition of a copper salt (CuCl2) in the spray solution of ZnO. Variation of structural, electrical, optical and thermoluminescence (TL) properties with doping concentrations is investigated in detail.

Optimization of Directivity of Point Source Array by Using Pseudostochastic Sequences
AN Kang, SHEN Yong, OU Da-Yi
Chin. Phys. Lett.    2008, 25 (2): 586-588.  
Abstract   PDF (187KB)
We investigate the methods to optimize the directivity of point source array by using pseudostochastic sequences. Maximum-length sequence (MLS) array and Quadratic-residue sequence (QRS) array are theoretically analysed, and their simulated responses are shown. The results indicate that pseudostochastic sequences can be used to optimize the directivity of point source array.
End-Pumped Slab Yb:YAG Crystal Emitting 1030 nm Laser at Room Temperature
XU Liu, ZHANG Heng-Li, MAO Ye-Fei, DENG Bo, HE Jing-Liang, XIN Jian-Guo
Chin. Phys. Lett.    2013, 30 (7): 074207.   DOI: 10.1088/0256-307X/30/7/074207
Abstract   PDF (412KB)
We demonstrate a 1030-nm laser with end-pumped slab Yb:YAG geometry at room temperature. A maximum power of 86 W output at the pump power of 323 W is obtained. The optical-optical efficiency is about 26.6% and the slope efficiency is 31%.
Polarimetric Laser Range-Gated Underwater Imaging
GUAN Jin-Ge, ZHU Jing-Ping, TIAN Heng
Chin. Phys. Lett.    2015, 32 (07): 074201.   DOI: 10.1088/0256-307X/32/7/074201
Abstract   PDF (677KB)
For conventional laser range-gated underwater imaging (RGI) systems, the target image is obtained based on the reflective character of the target. One of the main performance limiting factors of conventional RGI is that, when the underwater target has the same reflectivity as the background, it is difficult to distinguish the target from the background. An improvement is to use the polarization components of the reflected light. On the basis of conventional RGI, we propose a polarimetric RGI system that employs a polarization generator and a polarization analyzer to detect and recognize underwater objects. Experimental results demonstrate that, by combining polarization with intensity information, we are better able to enhance identification of the underwater target from other objects of the same reflectivity.
Directed Dynamic Small-World Network Model for Worm Epidemics in Mobile ad hoc Networks
ZHU Chen-Ping, **, WANG Li, LIU Xiao-Ting, YAN Zhi-Jun
Chin. Phys. Lett.    2012, 29 (1): 010504.   DOI: 10.1088/0256-307X/29/1/010504
Abstract   PDF (544KB)
We investigate the worm spreading process in mobile ad hoc networks with a susceptible-infected-recovered model on a two-dimensional plane. A medium access control mechanism operates within it, inhibiting transmission and relaying a message by using other nodes inside the node's transmitting circle during speaking. We measure the rewiring probability p with the transmitting range r and the average relative velocity v of the moving nodes, and map the problem into a directed dynamic small-world network. A new scaling relation for the recovered portion of the nodes reveals the effect caused by geometric distance, which has been ignored by previous models.
Investigation of Oxygen Vacancy and Interstitial Oxygen Defects in ZnO Films by Photoluminescence and X-Ray Photoelectron Spectroscopy
FAN Hai-Bo, YANG Shao-Yan, ZHANG Pan-Feng, WEI Hong-Yuan, LIU Xiang-Lin, JIAO Chun-Mei, ZHU Qin-Sheng, CHEN Yong-Hai, WANG Zhan-Guo
Chin. Phys. Lett.    2007, 24 (7): 2108-2111.  
Abstract   PDF (341KB)
ZnO films prepared at different temperatures and annealed at 900°C in
oxygen are studied by photoluminescence (PL) and x-ray photoelectron
spectroscopy (XPS). It is observed that in the PL of the as-grown films the green luminescence (GL) and the yellow luminescence (YL) are related, and after annealing the GL is restrained and the YL is enhanced. The O 1s XPS results also show the coexistence of oxygen vacancy (VO) and interstitial oxygen (Oi) before annealing and the quenching of the VO after annealing. By combining the two results it is deduced that the GL and YL are related to the VO and Oi defects, respectively.
Nonlinear Local Lyapunov Exponent and Quantification of Local Predictability
DING Rui-Qiang, LI Jian-Ping, HA Kyung-Ja
Chin. Phys. Lett.    2008, 25 (5): 1919-1922.  
Abstract   PDF (217KB)
Nonlinear local Lyapunov exponent (NLLE) is applied to quantitatively determine the local predictability limit of chaotic systems. As an example, we find that the local predictability limit of Henon attractor varies considerably with time, and some underlying phase-spatial structure does not appear. The local predictability limit of initially adjacent points in phase space may be completely different. This will cause difficulties in making the long-time analogue forecast.
Measurement of Electrical Conductivity of Porous Titanium and Ti6Al4V Prepared by the Powder Metallurgy Method
ZHU Ke, LI Cheng-Feng, ZHU Zhen-Gang
Chin. Phys. Lett.    2007, 24 (1): 187-190.  
Abstract   PDF (285KB)
Porous titanium and Ti6Al4V are produced by the powder metallurgy method. Dependence of the electrical conductivity on the porosity and pore size is investigated and the experimental results are correlative and compared with several earlier models. A newly modified Mori--Tanaka relationship based on the effective field method is proposed, which is successfully applied to describe the dependence of the electrical conductivity of porous titanium and Ti6Al4V on the porosity. The pore size has a minor effect on the electrical onductivity of both samples.
Grain Size Effect on Electrical Conductivity and Giant Magnetoresistance of Bulk Magnetic Polycrystals
LUO Wei, ZHU Lin-Li, ZHENG Xiao-Jing
Chin. Phys. Lett.    2009, 26 (11): 117502.   DOI: 10.1088/0256-307X/26/11/117502
Abstract   PDF (384KB)
By solving the Boltzmann transport equation and considering the spin-dependent grain boundary scattering, the distribution of electrons in grains and the electrical transport properties in the applied magnetic field are studied. With regard to the dominant influence of grain boundary scattering which is taken as a boundary condition for the electrical transport, the grain size-dependent electrical conductivity is investigated. In addition, the reorientation of the relative magnetization between grains brings the change of the electron spin when the magnetonanocrystalline material is subjected to the magnetic field, resulting in the remarkable giant magnetoresistance effect.
Thickness Dependence of Resistivity and Optical Reflectance of ITO Films
GAO Mei-Zhen, JOB R, XUE De-Sheng, FAHRNER W R
Chin. Phys. Lett.    2008, 25 (4): 1380-1383.  
Abstract   PDF (3862KB)
Indium-tin-oxide (ITO) films deposited on crystalline silicon wafer and Corning glass are prepared by direct-current magnetron sputtering method at room temperature with various thicknesses. The thickness dependences of structure, resistance and optical reflectance of ITO films are characterized.
The results show that when the film thickness is less than 40nm, the resistivity and optical reflectance of the ITO film changes remarkably with thickness. The optoelectrical properties trend to stabilize when the thickness is over 55nm. The GXRD result implies that the ITO film begins to crystallize if only the thickness is large enough.
Structural and Electrical Properties of PZT/PVDF Piezoelectric Nanocomposites Prepared by Cold-Press and Hot-Press Routes
ZHANG De-Qing, WANG Da-Wei, YUAN Jie, ZHAO Quan-Liang, WANG Zhi-Ying, CAO Mao-Sheng
Chin. Phys. Lett.    2008, 25 (12): 4410-4413.  
Abstract   PDF (508KB)
The 0-3 PZT/PVDF piezoelectric composites are prepared separately by hot-press and cold-press processes. The effects of the PZT content and the shaping-process on the composites are studied. The experimental results indicate that composites with 70% PZT nanopowders prepared by the hot-press method exhibit excellent piezoelectric and dielectric properties. The maxima of d33 and ε of the composites prepared by hot-press method are about 30% and 65% higher than those prepared by the cold-press method, respectively. This is mainly attributed to the favourable coupling of the two materials in the process of the hot press and the formation of the β-type PVDF, which possesses better electric properties.