A new algorithm for iterative reconstruction is suggested.It is named simple self-correlative algebraic reconstruction technique (SSART).With numerical simulation experiments,SSART was applied in reconstructing a non-...A new algorithm for iterative reconstruction is suggested.It is named simple self-correlative algebraic reconstruction technique (SSART).With numerical simulation experiments,SSART was applied in reconstructing a non-ideal-bordered field in order to test its reconstructive effect.For contrast,three current representative algebraic reconstruction(ARTs) including basic ART,simultaneous ART (SART) and modified SART (MSART) were simulated simultaneously.The calculated results and reconstructive accuracy are discussed with three kinds of error indexes,namely mean-square error (MSE),absolute value error (AVE) and peak error (PE).As the results,the indexes of reconstructive accuracy are much improved by the proposed SSART.The MSE and PE have been decreased by 63.6% on the order of magnitude 10-4 and 88.9% on the order of magnitude 0-2,respectively,compared to that of ART.It is concluded that SSART is one of the most super iterative reconstructing techniques.展开更多
This work is about the development of a super low noise amplifier with minimum power consumption and high gain for several wireless applications.The amplifier operates at frequency bands of 0.9-2.4 GHz and can be used...This work is about the development of a super low noise amplifier with minimum power consumption and high gain for several wireless applications.The amplifier operates at frequency bands of 0.9-2.4 GHz and can be used in many applications like Wireless local area network(WLAN),WiFi,Bluetooth,ZigBee and Global System for mobile communications(GSM).This new design can be employed for the IEEE 802.15.4 standard in industrial,scientific and medical(ISM) Band.The enhancement mode pseudomorphic high electron mobility transistor PHEMT is used here due to its high linearity,better performance and less noisy operation.The common source inductive degeneration method is employed here to enhance the gain of amplifier.The amplifier produces a gain of more than 17 dB and noise figure of about 0.5 dB.The lower values of S11 and S22 reflect the accuracy of impedance matching network placed at the input and output sides of amplifier.Agilent Advance Design System(ADS) is used for the design and simulation purpose.Further the layout of design is developed on the FR4 substrate.展开更多
An algorithm is suggested to compensate the inside fringe in reconstruction field for the iterative distortion when an opaque object exists.With numerical simulation, a model field with an opaque object is reconstruct...An algorithm is suggested to compensate the inside fringe in reconstruction field for the iterative distortion when an opaque object exists.With numerical simulation, a model field with an opaque object is reconstructed by a new algebraic reconstructing technique (ART),named Simple Self-correlative ART (SSART),which shows that the inside fringe of the reconstructed field is quite irregular with serious profile distortion.An algorithm of the compensation of the inside fringe for the iterative distortion is suggested and applied to the reconstruction of the field.It is found that the reconstructed field is quite similar to the model.With the compensation algorithm, the field with an opaque object in can be accurately reconstructed by SSART.展开更多
Correlation power analysis(CPA) has become a successful attack method about crypto-graphic hardware to recover the secret keys. However, the noise influence caused by the random process interrupts(RPIs) becomes an imp...Correlation power analysis(CPA) has become a successful attack method about crypto-graphic hardware to recover the secret keys. However, the noise influence caused by the random process interrupts(RPIs) becomes an important factor of the power analysis attack efficiency, which will cost more traces or attack time. To address the issue, an improved method about empirical mode decomposition(EMD) was proposed. Instead of restructuring the decomposed signals of intrinsic mode functions(IMFs), we extract a certain intrinsic mode function(IMF) as new feature signal for CPA attack. Meantime, a new attack assessment is proposed to compare the attack effectiveness of different methods. The experiment shows that our method has more excellent performance on CPA than others. The first and the second IMF can be chosen as two optimal feature signals in CPA. In the new method, the signals of the first IMF increase peak visibility by 64% than those of the tradition EMD method in the situation of non-noise. On the condition of different noise interference, the orders of attack efficiencies are also same. With external noise interference, the attack effect of the first IMF based on noise with 15dB is the best.展开更多
The transport characteristics of high temperature superconductor current and Josephson current is inves-tigated in the framework of the modified time-dependent Ginzburg-Landau model and the Lawrence-Doniach model.We e...The transport characteristics of high temperature superconductor current and Josephson current is inves-tigated in the framework of the modified time-dependent Ginzburg-Landau model and the Lawrence-Doniach model.We evaluated the vortex equation and found that the signs of the high temperature superconductor current and theJosephson current can reverse. Some explicit expressions for different cases are derived, which accord with experimentaldata.展开更多
Phase separations have been studied for graded-indium content In_xGa_(1-x)N/GaN multiple quantum wells(MQWs) with different indium contents by means of photoluminescence(PL),cathodeluminescence(CL) and time-re...Phase separations have been studied for graded-indium content In_xGa_(1-x)N/GaN multiple quantum wells(MQWs) with different indium contents by means of photoluminescence(PL),cathodeluminescence(CL) and time-resolved PL(TRPL) techniques.Besides the main emission peaks,all samples show another 2 peaks at the high and low energy parts of the main peaks in PL when excited at 10 K.CL images show a clear contrast for 3 samples,which indicates an increasing phase separation with increasing indium content.TRPL spectra at 15 K of the main emissions show an increasing delay of rising time with indium content,which means a carrier transferring from low indium content structures to high indium content structures.展开更多
基金This project was supported by China Postdoctoral Science Foun-dation(2004036121) the National Natural Science Foundation ofChina(10404022) Education Bureau of Shandong province(J04A63)
文摘A new algorithm for iterative reconstruction is suggested.It is named simple self-correlative algebraic reconstruction technique (SSART).With numerical simulation experiments,SSART was applied in reconstructing a non-ideal-bordered field in order to test its reconstructive effect.For contrast,three current representative algebraic reconstruction(ARTs) including basic ART,simultaneous ART (SART) and modified SART (MSART) were simulated simultaneously.The calculated results and reconstructive accuracy are discussed with three kinds of error indexes,namely mean-square error (MSE),absolute value error (AVE) and peak error (PE).As the results,the indexes of reconstructive accuracy are much improved by the proposed SSART.The MSE and PE have been decreased by 63.6% on the order of magnitude 10-4 and 88.9% on the order of magnitude 0-2,respectively,compared to that of ART.It is concluded that SSART is one of the most super iterative reconstructing techniques.
基金supported by the National Natural Science Foundation of China(Grant no. 61202399,61571063)
文摘This work is about the development of a super low noise amplifier with minimum power consumption and high gain for several wireless applications.The amplifier operates at frequency bands of 0.9-2.4 GHz and can be used in many applications like Wireless local area network(WLAN),WiFi,Bluetooth,ZigBee and Global System for mobile communications(GSM).This new design can be employed for the IEEE 802.15.4 standard in industrial,scientific and medical(ISM) Band.The enhancement mode pseudomorphic high electron mobility transistor PHEMT is used here due to its high linearity,better performance and less noisy operation.The common source inductive degeneration method is employed here to enhance the gain of amplifier.The amplifier produces a gain of more than 17 dB and noise figure of about 0.5 dB.The lower values of S11 and S22 reflect the accuracy of impedance matching network placed at the input and output sides of amplifier.Agilent Advance Design System(ADS) is used for the design and simulation purpose.Further the layout of design is developed on the FR4 substrate.
文摘An algorithm is suggested to compensate the inside fringe in reconstruction field for the iterative distortion when an opaque object exists.With numerical simulation, a model field with an opaque object is reconstructed by a new algebraic reconstructing technique (ART),named Simple Self-correlative ART (SSART),which shows that the inside fringe of the reconstructed field is quite irregular with serious profile distortion.An algorithm of the compensation of the inside fringe for the iterative distortion is suggested and applied to the reconstruction of the field.It is found that the reconstructed field is quite similar to the model.With the compensation algorithm, the field with an opaque object in can be accurately reconstructed by SSART.
基金supported by The National Natural Science Foundation of China under Grants 61571063,61501100 and 61472357
文摘Correlation power analysis(CPA) has become a successful attack method about crypto-graphic hardware to recover the secret keys. However, the noise influence caused by the random process interrupts(RPIs) becomes an important factor of the power analysis attack efficiency, which will cost more traces or attack time. To address the issue, an improved method about empirical mode decomposition(EMD) was proposed. Instead of restructuring the decomposed signals of intrinsic mode functions(IMFs), we extract a certain intrinsic mode function(IMF) as new feature signal for CPA attack. Meantime, a new attack assessment is proposed to compare the attack effectiveness of different methods. The experiment shows that our method has more excellent performance on CPA than others. The first and the second IMF can be chosen as two optimal feature signals in CPA. In the new method, the signals of the first IMF increase peak visibility by 64% than those of the tradition EMD method in the situation of non-noise. On the condition of different noise interference, the orders of attack efficiencies are also same. With external noise interference, the attack effect of the first IMF based on noise with 15dB is the best.
文摘The transport characteristics of high temperature superconductor current and Josephson current is inves-tigated in the framework of the modified time-dependent Ginzburg-Landau model and the Lawrence-Doniach model.We evaluated the vortex equation and found that the signs of the high temperature superconductor current and theJosephson current can reverse. Some explicit expressions for different cases are derived, which accord with experimentaldata.
基金Project supported by the National Natural Science Foundation of China(No.11174241)the Natural Science Foundation of Shandong Province,China(No.2009VRA06063)the Natural Science Foundation for Distinguished Young Scholars of Shandong Province, China(No.2008JQB01028)
文摘Phase separations have been studied for graded-indium content In_xGa_(1-x)N/GaN multiple quantum wells(MQWs) with different indium contents by means of photoluminescence(PL),cathodeluminescence(CL) and time-resolved PL(TRPL) techniques.Besides the main emission peaks,all samples show another 2 peaks at the high and low energy parts of the main peaks in PL when excited at 10 K.CL images show a clear contrast for 3 samples,which indicates an increasing phase separation with increasing indium content.TRPL spectra at 15 K of the main emissions show an increasing delay of rising time with indium content,which means a carrier transferring from low indium content structures to high indium content structures.