Yang Y.,Soochow University of China |
Guo M.,Shandong Computer Science Center National Supercomputer Center in Jinan |
Zhang G.,Institute of High Performance Computing of Singapore |
Li W.,Soochow University of China
Carbon | Year: 2017
We present a density-functional-theory study of the recently synthesized graphene-like carbon nitride monolayer (C2N) with transition metal atom (TM = Fe, Co and Ni) doping. We find that for three elements, the TM-C2N binding is strong and covalent in nature. While the pristine C2N is a semiconductor with non-magnetism at the ground state, the TM-C2N complexes exhibit metal characteristic and is spin-polarized. Particularly, a Fe atom on C2N can induce 3.91 μB magnetic moment with ferromagnetic coupling. For Co and Ni, smaller magnetic moment is observed with weaker coupling or even no coupling. The spin-polarization can be understood in the local-orbital picture, involving hybridizations of nitrogen's pz orbital with the 3d orbitals of metal. The work function of C2N can be effectively modulated by metal doping from 5.25 eV for pristine C2N to a range of 3.85–4.15 eV for doped ones. Our results indicate that the properties of C2N layer can be effectively modulated by chemical doping and the co-realization of metallic and ferromagnetic properties in doped C2N might find broad applications in the design of nanoscale electronic and spintronic devices. © 2017 Elsevier Ltd
Hao F.,Shandong Computer Science Center National Supercomputer Center in Jinan |
Luo X.,Shandong Computer Science Center National Supercomputer Center in Jinan |
Mu C.,Shandong Academy of Agricultural Sciences
Proceedings - 2016 International Conference on Smart City and Systems Engineering, ICSCSE 2016 | Year: 2016
The intelligent perception nodes for farmland environment information has the features of low cost and high efficiency, and with it the data in multiple crop growth cycle are available. Based on this, this paper, after making clear the relationship between farmland environmental factors and crop growth cycle and crop yield, aims at the establishment of environment-production model and building the system of crop growth environment perception and intelligent decision, in order to analyze agricultural data and give constructive advice about agricultural production, agricultural layout and agricultural scientific research. © 2016 IEEE.
Sun D.,Beihang University |
Liu B.,Shandong Computer Science Center National Supercomputer Center in Jinan
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2017
With the development of new web technologies, the Massive Open Online Course (MOOC) which aims at unlimited participation and access is emerging. In contrast to traditional education, learners could get access to filmed lectures and tests online anytime and anywhere. However, there still exists some problems with MOOCs. Currently, one major problem is the imbalance between teachers and learners online. In many courses, thousands of learners enroll in a class with a single instructor which could lead to bad learning effect and very low completion rates, so we propose crowdsourcing based teaching assistant assignment for MOOC in order to optimize the reasonable disposal of manpower. We present effective algorithms for the selection and assignment of teaching assistants. With experiments on various datasets, we verify the effectiveness of our proposed methods. © Springer International Publishing AG 2017.
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.
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.
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.