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Long R.,Beijing Normal University | Guo M.,Shandong Computer Science Center National Supercomputer Center in Jinan | Liu L.,Beijing Normal University | Fang W.,Beijing Normal University
Journal of Physical Chemistry Letters | Year: 2016

Black phosphorus (BP) is an appealing material for applications in electronics and optoelectronics because of its tunable direct band gap and high charge carrier mobility. For real optoelectronic device utilization, nonradiative electron-hole recombination should be slow because it constitutes a major pathway for charge and energy losses. Using time-domain density functional theory combined with nonadiabatic (NA) molecular dynamics, we show that nonradiative electron-hole recombination occurs within several tens of picoseconds in bilayer BP, agreeing well with experimental data. When a single layer of BP is stacked with monolayer MoS2, the recombination is reduced because of the increased band gap and reduced electron-phonon NA coupling compared to bilayer BP. The slow electron-phonon energy losses in BP-MoS2 van der Waals heterojunction relative to bilayer BP indicate that rationally stacking BP with other two-dimensional materials is an attractive route for designing novel and efficient photovoltaic materials. © 2016 American Chemical Society.


PubMed | Shandong University of Science and Technology and Shandong Computer Science Center National Supercomputer Center in Jinan
Type: Journal Article | Journal: PloS one | Year: 2016

In this paper, exact closed-form expressions are derived for the outage probability (OP) of the maximal ratio combining (MRC) scheme in the - shadowed fading channels, in which both the independent and correlated shadowing components are considered. The scenario assumes the received desired signals are corrupted by the independent Rayleigh-faded co-channel interference (CCI) and background white Gaussian noise. To this end, first, the probability density function (PDF) of the - shadowed fading distribution is obtained in the form of a power series. Then the incomplete generalized moment-generating function (IG-MGF) of the received signal-to-interference-plus-noise ratio (SINR) is derived in the closed form. By using the IG-MGF results, closed-form expressions for the OP of MRC scheme are obtained over the - shadowed fading channels. Simulation results are included to validate the correctness of the analytical derivations. These new statistical results can be applied to the modeling and analysis of several wireless communication systems, such as body centric communications.


Cheng G.H.,Shandong Computer Science Center National Supercomputer Center in Jinan | Sun R.R.,Shandong University of Technology
Advanced Materials Research | Year: 2014

Due to construction projects testing requirements work continuously for more than a week or even a month or so, so for a battery-powered portable heat and temperature acquisition system, its power consumption has the constraints. In accordance with the need of the acquisition system of actual engineering, this paper from two aspects of hardware and software to consider heat flux and temperature acquisition system of low power design, specific design ideas and implementation methods is also given in this paper. The test results demonstrate that the sleep state, the actual operating current is 0.59mA. A nominal 1000mAh lithium battery, the case of the sleep wake of five minutes, can work continuously for about 20 days, the case of 10 minutes to wake up dormant, can work continuously for about a month. © (2014) Trans Tech Publications, Switzerland.


Zhao D.,Shandong Computer Science Center National Supercomputer Center in Jinan | Wang L.,Shandong Computer Science Center National Supercomputer Center in Jinan | Li S.,Shandong Institute of Business and Technology | Li S.,National University of Defense Technology | And 3 more authors.
PLoS ONE | Year: 2014

Up to now, immunization of disease propagation has attracted great attention in both theoretical and experimental researches. However, vast majority of existing achievements are limited to the simple assumption of single layer networked population, which seems obviously inconsistent with recent development of complex network theory: each node could possess multiple roles in different topology connections. Inspired by this fact, we here propose the immunization strategies on multiplex networks, including multiplex node-based random (targeted) immunization and layer node-based random (targeted) immunization. With the theory of generating function, theoretical analysis is developed to calculate the immunization threshold, which is regarded as the most critical index for the effectiveness of addressed immunization strategies. Interestingly, both types of random immunization strategies show more efficiency in controlling disease spreading on multiplex Erdös-Rényi (ER) random networks; while targeted immunization strategies provide better protection on multiplex scale-free (SF) networks. Copyright: © 2014 Zhao et al.


Ge L.,Shandong Computer Science Center National Supercomputer Center in Jinan | Wang L.,Shandong Computer Science Center National Supercomputer Center in Jinan
Communications in Computer and Information Science | Year: 2014

Password recovery of RAR encrypted file is an important problem in computer forensics. It is difficult to deal with this problem by the traditional methods such as guess, dictionary, rainbow table and brute force. We give a new method based on parallel random search. The new method use a parallel stochastic approach on word selection in the dictionary attack. It can greatly improve the success rate of password recovery. And the experiment shows that the new approach is effective in the password recovery of RAR file. © Springer-Verlag Berlin Heidelberg 2014.


Xu L.-J.,Shandong Computer Science Center National Supercomputer Center in Jinan | Wang L.-H.,Shandong Computer Science Center National Supercomputer Center in Jinan
Journal of Harbin Institute of Technology (New Series) | Year: 2014

Memory analysis is one of the key techniques in computer live forensics. Especially, the analysis of a Mac OS X operating system's memory image file plays an important role in identifying the running status of an apple computer. However, how to analyze the image file without using extra ”mach_kernel” file is one of the unsolved difficulties. In this paper, we firstly compare several approaches for physical memory acquisition and analyze the effects of each approach on physical memory. Then, we discuss the traditional methods for the physical memory file analysis of Mac OS X. A novel physical memory image file analysis approach without using extra “mach_kernel” file is proposed base on the discussion. We verify the performance of the new approach on Mac OS X 10.8.2. The experimental results show that the proposed approach is simpler and more practical than previous ones.


Ge L.,Shandong Computer Science Center National Supercomputer Center in Jinan | Wang L.,Shandong Computer Science Center National Supercomputer Center in Jinan
Communications in Computer and Information Science | Year: 2015

The forensics for the iPhone backup files is an important problem in digital forensics. Since the backup files are often encrypted and the key chain data is always encrypted even if the data is not completely encrypted, it is difficult to deal with this problem by the traditional methods such as sequence brute force. In this paper, we give a new method based on parallel random search on CPU+GPU platform to solve this problem. The main principle of this method is to parallel random search the passwords in the given dictionary based on the CPU+GPU platform in order to crack the password of the encrypted iPhone backup files. An analysis of decryption and reduction method as well as the file structure is also shown in this paper. Finally the experiment result shows that the method given in this paper can greatly improve the efficiency of forensics for the encrypted iPhone backup files. © Springer-Verlag Berlin Heidelberg 2015.


Wang W.,Shandong Computer Science Center National Supercomputer Center in Jinan | Liu B.,Shandong Computer Science Center National Supercomputer Center in Jinan | Li G.,Shandong Computer Science Center National Supercomputer Center in Jinan
Conference Proceedings of the 4th International Symposium on Project Management, ISPM 2016 | Year: 2016

The paper analysis the business system, and takes into account the user's different requires of the business disaster recovery system, and then presents three sets of disaster recovery drills strategy which describe the applicable conditions and process of the drills. And at last we find that it has certain guiding significance to verify the applicability of the disaster recovery emergency plan and find problems for continuous improvement.


Wang M.,Shandong Computer Science Center National Supercomputer Center in Jinan | Wang M.,Shandong Provincial Key Laboratory of Computer Networks | Zhang Z.,Qufu Normal University
Journal of the Franklin Institute | Year: 2015

In this paper, the problem of globally stable adaptive fuzzy tracking control is addressed for a class of uncertain nonlinear systems in the canonical form. Instead of linearly parameterized fuzzy logic system (FLS), nonlinearly parameterized FLS is used to approximate the unknown nonlinear function. By combining the new parametrization of Gaussian membership function and the signal replacement approach, a novel adaptive fuzzy controller is designed. It is shown that all signals in the closed-loop system are globally bounded and that the tracking error converges to zero asymptotically. A simulation example is included to illustrate the effectiveness of the proposed approach. © 2015 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.


PubMed | Northwestern Polytechnical University and Shandong Computer Science Center National Supercomputer Center in Jinan
Type: | Journal: Scientific reports | Year: 2016

From transportation networks to complex infrastructures, and to social and economic networks, a large variety of systems can be described in terms of multiplex networks formed by a set of nodes interacting through different network layers. Network robustness, as one of the most successful application areas of complex networks, has attracted great interest in a myriad of research realms. In this regard, how multiplex networks respond to potential attack is still an open issue. Here we study the robustness of multiplex networks under layer node-based random or targeted attack, which means that nodes just suffer attacks in a given layer yet no additional influence to their connections beyond this layer. A theoretical analysis framework is proposed to calculate the critical threshold and the size of giant component of multiplex networks when nodes are removed randomly or intentionally. Via numerous simulations, it is unveiled that the theoretical method can accurately predict the threshold and the size of giant component, irrespective of attack strategies. Moreover, we also compare the robustness of multiplex networks under multiplex node-based attack and layer node-based attack, and find that layer node-based attack makes multiplex networks more vulnerable, regardless of average degree and underlying topology.

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