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Search Results: 1 - 10 of 29211 matches for " Xiaojun Sun "
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Multi-Branch Fractional Multi-Bit Differential Detection of Continuous Phase Modulation with Decision Feedback  [PDF]
Jinhua Sun, Xiaojun Wu
Communications and Network (CN) , 2011, DOI: 10.4236/cn.2011.31004
Abstract: Differential detection of continuous phase modulation suffers from significant intersymbol interference. To reduce bit error rate, multi-branch fractional multi-bit differential detection (MFMDD) with decision feed-back is proposed. By introducing decision feedback in multi-bit differential detected signals, severe inter-symbol interference can be removed. Simulation results show that the proposed structure can greatly im-proves the performance compared with MFMDD without decision feedback, and the performance of 9 FMDD is very near to the performance of the coherent detection.
Heavy Metals’ Spatial Distribution Characteristics in a Copper Mining Area of Zhejiang Province  [PDF]
Hua Sun, Juan Li, Xiaojun Mao
Journal of Geographic Information System (JGIS) , 2012, DOI: 10.4236/jgis.2012.41007
Abstract: The spatial distribution characteristics of six heavy metals and metalloid in soil of Zhuji Lipu copper mining area, Zhejiang Province, was studied by using geostatistics approaches combined with GIS. These elements included Pb, As, Cr, Cu, Zn and Ni. The statistical analyses showed that concentrations of these elements were lognormal distribution. Concentrations of Pb, As, Cu, Zn and Ni were strongly correlated with each other indicating that these elements in soils may be from the same pollution source. However, accumulation of Cr was unique with its geometric mean being close to that in the control soil. This indicates that Cr content was mainly influenced by soil factors. The Kriging method was applied to estimate the unobserved points. The Kriging interpolation maps reflected significant spatial distribution of these elements as influenced by both pollution and geological factors. The present study indicated that GIS based geostatistics method could accurately analyze the spatial variation of heavy metals and metalloid in the mining area. Overall, higher concentrations of heavy metals and metalloid were found in the center of both the north and south sides. The content of copper in the south was significantly higher than that in the north due to paddy field land uses. In addition, the terrain of four terraces tilted to the center and the broad irrigation accident occurred in the 4th trench in the south of sampling area were also contributed to the higher concentrations of these elements.
New integral formula and its applications to light nucleus reactions
Xiaojun Sun,Jingshang Zhang
Physics , 2015, DOI: 10.1103/PhysRevC.92.061601
Abstract: A new integral formula, which has not been compiled in any integral tables or mathematical softwares, is proposed to obtain the analytical energy-angular spectra of the particles that are sequentially emitted from the discrete energy levels of the residual nuclei in the statistical theory of light nucleus reaction (STLN). In the cases of the neutron induced light nucleus reactions, the demonstration of the kinetic energy conservation in the sequential emission processes becomes straightforward thanks to this new integral formula and it is also helpful to largely reduce the volume of file-6 in nuclear reaction databases. Furthermore, taking p+$^9$Be reaction at 18 MeV as an example, this integral formula is extended to calculate the energy-angular spectra of the sequentially emitted neutrons for proton induced light nucleus reactions in the frame of STLN.
Statistical theory of light nucleus reaction and application to $^9$Be(p, xn) reaction
Xiaojun Sun,Jingshang Zhang
Physics , 2015,
Abstract: A statistical theory of light nucleus reaction (STLN) is proposed to describe both neutron and light charged particle induced nuclear reactions with 1p-shell light nuclei involved. The dynamic of STLN is described by the unified Hauser-Feshbach and exciton model, of which the angular momentum and parity conservations are considered in equilibrium and pre-equilibrium processes. The Coulomb barriers of the incident and outgoing charged particles, which seriously influence the open reaction channels, could be reasonably considered in the incident channel and the different outgoing channels. In kinematics, the recoiling effects in various emission processes are taken strictly into account. Taking $^9$Be(p, xn) reaction as an example, we calculate the double-differential cross sections of outgoing neutrons and charged particles using PUNF code in the frame of STLN. The calculated results agree very well with the existing experimental neutron double-differential cross sections at $E_p=18$ MeV, and indicate that PUNF code is a powerful tool to set up file-6 in the reaction data library for the light charged particle induced nuclear reactions with 1p-shell light nuclei involved.
Outage probability of selective decode and forward relaying with secrecy constraints
Xiaojun Sun,Chunming Zhao
Mathematics , 2011,
Abstract: We study the outage probability of opportunistic relay selection in decode-and-forward relaying with secrecy constraints. We derive the closed-form expression for the outage probability. Based on the analytical result, the asymptotic performance is then investigated. The accuracy of our performance analysis is verified by the simulation results.
Sporadic Creutzfeldt-Jakob Disease Presenting with Visual Disturbance—A Case Report in China  [PDF]
Guohong Tian, Lin Sun, Yunhong He, Xiaojun Zhang
International Journal of Clinical Medicine (IJCM) , 2013, DOI: 10.4236/ijcm.2013.47057
Abstract: Creutzfeldt-Jakob disease (CJD) is a rare but fatal neurodegenerative prion disease. Classic CJD comprises a clinical triad of rapidly progressive dementia, myoclonus, and EEG abnormality. At initial presentation, this classic triad is present only in a minority of cases. Visual impairment is one of the predominant manifestations in the course of CJD, especially in Heidenhain variant phenotype. We reported a case presenting with progressive blurred vision, along with other neurological symptoms, who diagnosed as sporadic CJD with cortical blindness in China.

Gravity Drainage Visualization Experimental Study of Heavy Oil Reservoirs  [PDF]
Lili Liu, Shuren Yang, Chunsheng Wang, Qiji Sun, Xiaojun Zhong
Energy and Power Engineering (EPE) , 2016, DOI: 10.4236/epe.2016.85023
Abstract: Liaohe oilfield gravity drainage assisted steam flooding of heavy oil reservoir has made significant development effect, but the drain rule of condensate is unclear in the process of development. Heavy oil drainage microscopic visualization experimental study of using core model of glass etching, drainage process simulation of heavy oil reservoir and its influence factors were analyzed. Its method turns the drainage process of images into computer numerical signal through the image acquisition system, intuitive display flow pattern of drainage, and analyses the influence of homogeneity and the pressure differential regulation of drainage through the experimental data. The experiment results show that condensate around the steam chamber has a corresponding drainage channel, not uniform or diarrhea in the gravity drainage assisted steam flooding process. At the beginning of the drainage channels formation, the instantaneous drainage amount along with the change of pressure difference is not obvious. Instantaneous drainage amount increases with increasing pressure difference in the medium term. It tends to be stable in the later. The time of drainage channels to form homogeneous core is earlier than heterogeneous core. After the drainage channel, differential effects on heterogeneous core than homogeneous core of instantaneous drainage water.
Low complexity Chase-2 decoding of concatenated codes
XiaoJian Liu,ChunMing Zhao,XiaoJun Sun
Chinese Science Bulletin , 2010, DOI: 10.1007/s11434-009-3572-y
Abstract: The concatenated codes are widely used in current communication systems, such as satellite communication systems and WiMAX system. The objective of this study was to present a low complexity iterative soft decoding algorithm for concatenated codes. The concatenation was between a Reed-Solomon (RS) code and recursive systematic convolutional (RSC) code. The reduction in computational complexity was achieved by simplifying the Chase-2 decoder for RS codes with limited usage of test patterns. The processing of soft information between inner and outer decoders was also discussed. Simulation results showed that the proposed algorithm could achieve a good trade-off between complexity and performance.
Pre-neutron emission mass distributions for low-energy neutron-induced actinide fission
Xiaojun Sun,Chenggang Yu,Ning Wang
Physics , 2012, DOI: 10.1103/PhysRevC.85.014613
Abstract: According to the driving potential of a fissile system, we propose a phenomenological fission potential for a description of the pre-neutron emission mass distributions of neutron-induced actinide fission. Based on the nucleus-nucleus potential with the Skyrme energy-density functional, the driving potential of the fissile system is studied considering the deformations of nuclei. The energy dependence of the potential parameters is investigated based on the experimental data for the heights of the peak and valley of the mass distributions. The pre-neutron emission mass distributions for reactions 238U(n, f), 237Np(n, f), 235U(n, f), 232Th(n, f) and 239Pu(n, f) can be reasonably well reproduced. Some predictions for these reactions at unmeasured incident energies are also presented.
Closed-Form Expressions for Relay Selection with Secrecy Constraints
Xiaojun Sun,Chunming Zhao,Ming Jiang
Mathematics , 2010,
Abstract: An opportunistic relay selection based on instantaneous knowledge of channels is considered to increase security against eavesdroppers. The closed-form expressions are derived for the average secrecy rates and the outage probability when the cooperative networks use Decode-and-Forward (DF) or Amplify-and-Forward (AF) strategy. These techniques are demonstrated analytically and with simulation results.
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