摘要：
When laser pulses propagate in an inhomogeneous nonlinear medium, we theoretically investigate the evolution of laser pulses by analytically solving the (3 + 1)-dimensional generalized nonlinear Schrodinger equation with variable coefficients and optical lattice. A series of chirped-free and chirped analytic solutions, such as soliton solutions are found and intensities evolution of these analytic solutions are studied in detail. In the absence of optical lattice, we find that the intensities evolution of chirped-free and chirped analytic solutions vary regularly when the diffraction coefficient is the same as the dispersion coefficient. When the diffraction coefficient is different from the dispersion coefficient, the intensities evolution of chirped-free analytic solutions are regular variation, but the intensities evolution of chirped analytic solutions are irregular. In the presence of optical lattice, the intensities evolution of chirped analytic solutions vary regularly because the diffraction coefficient and the dispersion coefficient are always identical. (C) 2017 Elsevier GmbH. All rights reserved.
摘要：
[Pr0.7Sr0.3MnO3/La0.5Ca0.5MnO3]20 superlattices were epitaxially fabricated on (001) MgO substrates with 24 nm La0.5Ca0.5MnO3 (LCMO) buffer layer by pulsed laser deposition. As the thickness of Pr0.7Sr0.3MnO3 (PSMO) layer and LCMO layer is not identical, non-uniformity in the superlattice period thickness will occur and result in lower metal–insulator transition temperature and larger magnetoresistance (MR) at a wide low-temperature range. Furthermore, the percolation model was used to quantitatively understand the transport mechanism of superlattice. Our research results demonstrate that inhomogeneous layer thickness accompanied with charge ordering phase separation can strongly influence the transport properties of superlattice. Enhanced magnetoresistance at a wide temperature range provides possibilities for practical application in manganite-based film devices.
摘要：
For improving the quality of positron emission tomography (PET) images, the partial differential equation median (PDEmedian) algorithm which incorporates an anisotropic diffusion (AD) filter into the median root prior (MRP) algorithm was proposed. However, due to the shortcomings of the AD filter, the PDEmedian algorithm is difficult to realize. This work aims to solve this problem by introducing a new diffusion model into the PDEmedian. The proposed algorithm shows its positive effects on image reconstruction and denoising. Experimental results present that the new algorithm can preserve sharp edges while reducing noise at the same time. Furthermore, in comparison to other similar reconstruction algorithms, the proposed method is less sensitive to the value of the gradient threshold and the adjustment of the diffusion number.
摘要：
Based on a modified cross-correlation technique, we experimentally demonstrate a technique for measuring the spatial–temporal intensity of laser pulses. Pulse widths at different spatial positions of the ultrashort pulse are measured by changing the scan position of the probe beam. Due to the existence of residual chirp in the transverse position, pulse widths at the center of the beam are less than that at the edge. By measuring the temporal evolution in the fastest growth area of spatial intensity during small-scale self-focusing, we find that its pulse width decreases as power increases because of the spatial–temporal coupling effect. The results show that this method not only can be used to accurately measure the pulse width at any one spatial position of the beam, but can also be useful for real-time monitoring of the spatial–temporal evolution.
摘要：
In recent years, trap-related interfacial transport phenomena have received great attention owing to their potential applications in resistive switching devices and photo detectors. Not long ago, one new type of memristive interface that is composed of F-doped SnO_2 and Bi_2S_3 nano-network layers has demonstrated a bivariate-continuous-tunable resistance with a swift response comparable to the one in neuron synapses and with a brain-like memorizing capability. However, the resistive mechanism is still not clearly understood because of lack of evidence, and the limited improvement in the development of the interfacial device. By combining I-V characterization, electron energy-loss spectroscopy, and firstprinciple calculation, we studied in detail the macro/micro features of the memristive interface using experimental and theoretical methods, and confirmed that its atomic origin is attributed to the traps induced by O-doping. This implies that impurity-doping might be an effective strategy for improving switching features and building new interfacial memristors.
摘要：
Collective oscillations of free electrons generate plasmons on the surface of a material. A whispering-gallery microcavity effectively confines the light field on its surface based on the total reflection from its internal wall. When these two kinds of electromagnetic waves meet each other, the stimulated emissions from an individual ZnO microrod were enhanced more than 50-fold and the threshold was reduced after the whispering-gallery microcavity was coated with a monolayer of graphene and Al nanoparticles. The improvement of the lasing performance was attributed to the synergistic energy coupling of the graphene/Al surface plasmons with ZnO excitons. The lasing characteristics and the coupling mechanism were investigated systematically.
摘要：
Sparse matrix-vector multiplication (SpMV) is an important issue in scientific computing and engineering applications. The performance of SpMV can be improved using parallel computing. The implementation and optimization of SpMV on GPU are research hotspots. Due to some irregularities of sparse matrices, the use of a single compression format is not satisfactory. The hybrid storage format can expand the range of adaptation of the compression algorithms. However, because of the imbalance of non-zero elements, the parallel computing capability of a GPU cannot be fully utilized. The parallel computing capability of a CPU is also rising due to increased number of cores in CPU. However, when a GPU is computing, the CPU controls the process instead of contributing to the computational work. It leads to under-utilization of the computing power of CPU. Due to the characteristics of the sparse matrices, the data can be split into two parts using the hybrid storage format to be allocated to CPU and GPU for simultaneous computing. In order to take full advantage of computing resources of CPU and GPU, the CPU-GPU heterogeneous computing model is adopted in this paper to improve the performance of SpMV. With analysis of the characteristics of CPU and GPU, an optimization strategy of sparse matrix partitioning using a distribution function is proposed to improve the computing performance of SpMV on the heterogeneous computing platform. The experimental results on two test machines demonstrate noticeable performance improvement. (C) 2017 Elsevier Inc. All rights reserved.
通讯机构：
[Li, Hongjian] C;Cent S Univ, Coll Phys & Elect, Changsha 410083, Peoples R China.
摘要：
We numerically investigate the optical characteristics of a metal-dielectric-metal (MDM) waveguide side-coupled with two identical multimode stub resonators. Double plasmon-induced transparency (PIT) peaks with narrow full width at half maximum (FWHM) and high quality factor (Q-factor) can be observed in this structure. The Q-factors of PIT peaks in two stub resonators system are larger than those in single stub resonator system. A multimode coupled-radiation oscillator theory (MC-ROT), which is derived from ROT, is proposed to analyze the spectral response in the multimode system for the first time. The analytical results are confirmed by the finite-difference time-domain (FDTD) simulation results. We can also find that the Q-factors of the two PIT peaks have an opposite evolution tendency with the change of the stubs parameters and the maximum can reach to 427. These results may provide some applications for ultrasensitive sensors, switches and efficient filters.
期刊：
Multimedia Tools and Applications,2016年75(23):15601-15617 ISSN：1380-7501
通讯作者：
Zhang, Yudong
作者机构：
[Yang, Gelan] Hunan City Univ, Sch Informat Sci & Engn, Yiyang 413000, Peoples R China.;[Zhang, Yudong; Wang, Shuihua; Ji, Genlin] Nanjing Normal Univ, Sch Comp Sci & Technol, Nanjing 210023, Jiangsu, Peoples R China.;[Zhang, Yudong; Feng, Chunmei; Wang, Qiong; Yang, Jiquan] Jiangsu Key Lab 3D Printing Equipment & Mfg, Nanjing 210042, Jiangsu, Peoples R China.;[Dong, Zhengchao] Columbia Univ, Translat Imaging Div, New York, NY 10032 USA.;[Dong, Zhengchao] Columbia Univ, MRI Unit, New York, NY 10032 USA.
通讯机构：
[Zhang, Yudong] N;[Zhang, Yudong] J;Nanjing Normal Univ, Sch Comp Sci & Technol, Nanjing 210023, Jiangsu, Peoples R China.;Jiangsu Key Lab 3D Printing Equipment & Mfg, Nanjing 210042, Jiangsu, Peoples R China.
摘要：
It is very important to early detect abnormal brains, in order to save social and hospital resources. The wavelet-energy was a successful feature descriptor that achieved excellent performances in various applications; hence, we proposed a novel wavelet-energy based approach for automated classification of MR brain images as normal or abnormal. SVM was used as the classifier, and biogeography-based optimization (BBO) was introduced to optimize the weights of the SVM. The results based on a 5 x 5-fold cross validation showed the performance of the proposed BBO-KSVM was superior to BP-NN, KSVM, and PSO-KSVM in terms of sensitivity and accuracy. The study offered a new means to detect abnormal brains with excellent performance.
关键词：
Advanced Encryption Standard New Instruction;counter mode;encryption speed;encryption speedup;encryption time;OpenMP;parallel encryption;performance
摘要：
In the open environment of cloud computing, a large amount of user data needs to be encrypted/decrypted fast to maintain confidentiality and provide high quality of service. Advanced Encryption Standard (AES), the standard encryption algorithm, has better security and efficiency compared to its competitive algorithms, so it is widely used in cloud computing and other fields. However, the implementation of AES based on software still has the problem of low efficiency; whereas the implementation of AES based on hardware needs to purchase special purpose devices. Adopting the method of special instruction sets can resolve the above two drawbacks. Therefore, we propose a fast parallel cryptographic algorithm, NIPAES, which is based on the AES-NI (New Instructions) instruction set and CPU multiple cores. NIPAES makes use of the block property of AES and the parallel property of Counter (CTR) model, adopts OpenMP to evenly distribute workloads to each thread, which performs AES-NI instructions to complete encryption/decryption. Compared to CPU serial AES based on lookup tables, CPU parallel AES, and serial AES based on AES-NI, NIPAES has significant improvement on performance. The experimental results show that NIPAES achieves the average speedups of 3197.78x, 196.12x, and 7.71x, compared to the other aforementioned algorithms, respectively.
通讯机构：
[Tian, Ye] H;[Tian, Ye] U;Hunan City Univ, Sch Commun & Elect Engn, Yiyang 413000, Peoples R China.;Univ Ghent, Dept Informat Technol, Photon Res Grp, IMEC, B-9000 Ghent, Belgium.
关键词：
Meyer-Neldel rule;persistent photocurrent;trap-limited current
摘要：
A theoretical model is established to describe the emergence of the Meyer-Neldel rule (MNR) based on trap-limited current (TLC) theory. The model produces both MNR and anti-MNR behavior, and is available to various trap distributions. Moreover, TLC-based MNR is connected to persistent photocurrent (PPC) phenomenon. The information from MNR and PPC as well as their connection can be used to probe the distribution of the traps in materials.
作者机构：
[Shi, Zengliang; Zhu, Qiuxiang; Qin, Feifei; Lu, Junfeng; Wang, Yueyue; Xu, Chunxiang] Southeast Univ, State Key Lab Bioelect, Sch Biol Sci & Med Engn, Nanjing 210096, Jiangsu, Peoples R China.;[Zhu, Qiuxiang] Hunan City Univ, Coll Commun & Elect Engn, Yiyang 413000, Peoples R China.
通讯机构：
[Xu, Chunxiang] S;Southeast Univ, State Key Lab Bioelect, Sch Biol Sci & Med Engn, Nanjing 210096, Jiangsu, Peoples R China.
摘要：
In this paper, ZnO microdisks with sputtering of Au nanoparticles were prepared to explore their plasmon/exciton coupling effect. An obvious blue shift and enhanced excitonic emission intensity were observed in the PL spectra of as-grown and Au-sputtered ZnO samples at room temperature. The investigation on the absorption spectra and temperature-dependent PL spectra has been demonstrated the Burstein-Moss effect behind the optical phenomena. These results revealed the coupling dynamics between the metal localized surface plasmon and semiconductor exciton.
作者机构：
[Shi, Zengliang; Zhu, Qiuxiang; Qin, Feifei; Zhu, Zhu; Lu, Junfeng; Xu, Chunxiang] Southeast Univ, Sch Biol Sci & Med Engn, State Key Lab Bioelect, Nanjing 210096, Jiangsu, Peoples R China.;[Zhu, Qiuxiang] Hunan City Univ, Coll Commun & Elect Engn, Yiyang 413000, Peoples R China.
通讯机构：
[Xu, Chunxiang] S;Southeast Univ, Sch Biol Sci & Med Engn, State Key Lab Bioelect, Nanjing 210096, Jiangsu, Peoples R China.
关键词：
Dual-band;Fabry-Perot lasing;ZnO microbelt;Vapor-phase transport
摘要：
Dual-band semiconductor microbelt lasing are promising for multifunctional applications ranging from optical communication to spectroscopy analysis. Here, we demonstrated a dual-band Fabry-Perot (F-P) lasing from both length and width directions in a single ZnO microbelt. The lasing performance, spectral variation and mode structure significantly depended on the cavity size, which corresponded to the length and width of the ZnO microbelts. The resonant process and mechanism were investigated systematically through the experimental analysis and numerically FDTD simulation. The results of the dual band F-P lasing modes and wide lasing wavelength are helpful to design the dual-wavelength electronic and optoelectronic devices. (C) 2016 Elsevier B.V. All rights reserved.
摘要：
By means of the semidiscrete multiple-scale method, we study the existence and properties of high-order envelope solitons and discrete breathers in a homogeneous DNA chain model that is based on pairing enthalpies and site-dependent finite stacking. We obtain the analytical solutions for an envelope soliton, and find that at the Brillouin zone center, discrete breather solutions can appear below the bottom of the phonon band. The behavior of two solitons in collisions and the stability of discrete breathers are confirmed by numerical simulations of the exact equations of the system.
