Table of Content

20 May 2013, Volume 49 Issue 3

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Special Relativity and Upper Limit for Speed

DAI Youshan

2013, 49(3):  356-364. 

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The author presents a proof that the Galilean transformation is the only linear transformation of space and time that permits an arbitrarily large speed for particles which have rest frame. Consequently, there is a finite speed limit for any non-Galilean linear transformations. Given such speed limit vm, a new derivation of the relativistic mass-velocity and mass-energy relations for massive particles is presented, and then obtains the general Lorentz transformations based on the consideration of relativistic dynamics. New derivation does not require the assumption of constant speed of light, nor is it restricted to particular form of space and time transformation. The new relativistic formulas are not related directly to the speed of light c, but are instead parameterized by the speed limit vm. The well-known Galilean transformation is recovered from the general Lorentz transformation by taking the vm→∞ limit, and the numerical value of vm should be determined from experiments.

Atomistic Simulations of Mechanical Properties of Graphene under Heavy Ion Irradiation

LIANG Li,ZHAO Shijun,WANG Yugang,XUE Jianming

2013, 49(3):  365-370. 

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The influence of ion irradiation on graphene’s mechanical properties was investigated using molecular dynamics simulations (MD) including Young’s modulus, stress and strain. Incident ions were C ions with 1 keV, and the situations under different incident doses were studied, including 2.00×10¹³, 6.01×10¹³, 1.00×10¹⁴ and 2.00×10¹⁴cm^-2, respectively. The results show that defects, such as single, double vacancies and complex defects, are introduced by bombardment. They have a great effect on graphene’s mechanical properties, for example, two single vacancies can make Young’s modulus decreasing from 780.19 GPa to 128.77 GPa, and stress from 161.81 GPa to 30.85 GPa, compared with perfect graphene. The more defects in graphene, the effect will be greater. In addition, the physical mechanism of graphene’s deformation and cracking was taken over.

Transient Thermal Response of Pure and Oxide Dispersion Strengthened Tungsten Alloys

HE Shukai,YAN Sha,ZHU Yizhou,ZHANG Boyao,XUE Jianming,WANG Yugang

2013, 49(3):  349-355. 

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Thermal response of pure and two kinds of oxide dispersion strengthened tungsten alloys were investigated using intense pulsed ion beam (IPIB) device. Scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX) were used to examine the surface modifications and the distributions of dispersion elements. By comparing the results, it is found that pure tungsten show a better resistance to thermal shock. From the perspective of the tolerance of heat load, WL10 and WYT are not recommended for PFMs.

Controlled Synthesis and Luminescent Properties of Cubic Lu2O3:Eu3+ Nanocrystals

LI Yanping,YU Bin,DAI Yu

2013, 49(3):  371-376. 

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Lu₂O₃:Eu³⁺ nanocrystals with various shapes, such as nanorods, nanosheets, and nanoparticles, were synthesized by a hydrothermal approach only through adjusting the pH values of the precursor solutions. The prepared Lu₂O₃:Eu³⁺ nanocrystals were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, photoluminescence (PL) spectroscopy, and fluorescence lifetime (FL). With decreasing the samples sizes from nanorods to nanosheets and finally to nanoparticles, the photoluminescence intensity decreases drastically. It is attributed to the gradual increase of OH^- content, which attaches to the surface of nanocrystals, accelerates the nonradiative relaxation and thus lowers the luminescent efficiency. Moreover, the gradually enhanced 624 nm emission line and the continuously extended long excited tails of the charge transfer bands at the long wavelength side, which all originate from the Eu³⁺ ions at or near the surface, are also observed in Lu₂O₃:Eu³⁺ nanocrystals.

Quasi-Particle Band Structure and Enhanced Excitonic Effect of Silicane by Using GW and BSE Calculation

FEI Ruixiang,LUO Guangfu,GAO Zhengxiang,Lü Jing

2013, 49(3):  377-382. 

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The authors present first-principles calculations of the quasiparticle correction and the optical absorption of chairlike silicane fully hydrogenated silicene by using GW method and Bethe-Salpeter equation (BSE). Electron-electron interaction significantly affects the band structure of chairlike silicane. The indirect band gap of chairlike silicane increases from 2.08 to 3.53 eV and the direct quasiparticle band gap increases from 2.44 to 3.85 eV upon inclusion of the quasiparticle correction. Electron-hole interaction significantly affects the optical absorption of chairlike silicane. The binding energy of the binding exciton is about 0.40 eV, much larger than the value of 15 meV in the bulk Si. The enhanced excitonic effect is expected to be of importance in optoelectronic applications of silicene-based nanostructures.

A K-Band VCO Based on EBG Resonator

XU Feng,WANG Xin’an,CHEN Xu

2013, 49(3):  383-388. 

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A miniaturized K-band VCO (voltage controlled oscillator) using GaAs pHEMT device is presented. A compact mushroom-type edge-located vias electromagnetic bandgap (ELV-EBG) resonator loaded with a varactor is adopted instead of conventional resonator. The parallel feedback structure VCO is designed to operate from 22.9 GHz to 25.6 GHz. The measured results show that the proposed VCO provides a maximum output power of 10.4 dBm at 23.6 GHz with output power flatness less than 1 dB from 24 GHz to 25.4 GHz. The phase noise of the VCO with ELV-EBG resonator is around ?95 dBc/Hz at 1 MHz offset from carrier. The size of this compact VCO is about 17 mm×7.5 mm.

A Network Community Detection Algorithm via Constrained Label Propagation with Maximization of Similarity-Based Modularity

HUANG Jianbin,ZHONG Xiang,SUN Heli,MAO Wanting

2013, 49(3):  389-396. 

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A fast network community detection algorithm, MLPA, was proposed based on constrained label propagation with maximization of similarity-based modularity. The update process was completed via constrained maximization of similarity-based modularity model. The application of model and structural-similarity makes the accuracy high and the result fits in with character of community, which is densely inter-connected and sparsely connected to other parts of the network. Combined with experimental result that most of the vertices can be assigned to the proper community only within five iterations, the algorithm tries to stop the update process when labels reaches stable. Thus it can reduce the running time greatly. MLPA is efficient for detecting communities in large-scale networks without traditional adjacency matrix calculation.

Numerical Simulation of Cooling Tower Influences on Atmospheric Dispersion

CAI Xuhui,LIU Xiao,KANG Ling,LIU Xinjian

2013, 49(3):  409-416. 

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Disturbances of cooling towers on wind and turbulence field were simulated with a computational fluid dynamics model, Fluent. The influence on atmospheric dispersion was simulated by using a Lagrangian stochastic particle model. With 4 cooling towers and 4 emission stacks, and a typical wind speed of 1.5 m/s at a nuclear power station site, flow disturbances under neutral condition were simulated for three wind directions, i.e., ESE, SSE and SW. Dispersion plumes and their standard deviations were calculated for each wind direction and 2 selected stacks. Results show that, in case of wind direction with least disturbance on the air flow, there can be almost no influence of the cooling tower at the dispersion. While with significant influence of the air flow disturbance, the standard deviations of plumes can be increased for 2 and 1 stability classes in horizontal and vertical direction. The influence is mostly significant within 1 km of downwind distance.

The Influence of Stratospheric Anomalies on the Northeast Cold Vortex

WAN Xiaomin,FU Zuntao,HU Yongyun

2013, 49(3):  417-425. 

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The purpose of the study is to investigate influences of stratospheric circulation anomalies on NCV. Using the NCEP/NCAR (daily and month mean) dataset over 1958?2010, the authors performed statistical and composite analyses on the characteristics and three dimensional structures of NCV for stratospheric northern-hemisphere annular mode anomalies. It shows that NCV has more frequent occurrences and longer duration during negative stratosphere NAM anomalies than that during positive NAM anomalies. Composite results show that NCV is stronger during negative stratospheric NAM anomalies than that during positive NAM anomalies. It is also found that during negative stratospheric NAM anomalies NCV is more closely related to downward, eastward and equatorward propagation of stratospheric anomalies, indicating that negative stratospheric NAM may enhance formation and development of NCV and lead to colder weather in Northeastern China. The results have important implications for medium range forecasting NCV in the winter season.

A Micro-Pulse Lidar Observation of Aerosol in Beijing and Retrieval Algorithm Research

LIN Changqing,YANG Dongwei,LI Chengcai,LI Qian,SHI Guangming,WANG Yefang,ZHOU Yinliang,LIU Mengjuan

2013, 49(3):  426-434. 

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The MPL observation data in Beijing is used to develop two new algorithms which will not need to refer to the low SNR signal in high altitude. In the first algorithm, the boundary in mixing layer is chosen in the Fernald’s theory. Then the lidar constant can be retrieved by combining AOD. Compared with the data from the automatic meteorological station locates in the same place, this algorithm seems viable for lidar’s extinction coefficient retrieval. In the second algorithm, since the range corrected lidar data near the surface is linear relate to the surface extinction coefficient, the visibility data in the surface could be used to calculate the lidar constant. The result of the lidar constant and the average extinction-to-backscatter ratio during the experiment period are similar to the first algorithm. In these two algorithms, the lidar constant is retrieved without using the high altitude signal. In the end, the lidar observation of a classic aerosol case when a Siberian High passes through Beijing is analyzed. By comparing the lidar observation with the Nanjiao Observation Station data, the lidar retrieval and the new algorithm are considered to be reliable.

A Study on Characteristics of Cospectra in a Disturbed Surface Layer

JIANG Haimei,LIU Shuhua,LIU Heping

2013, 49(3):  435-442. 

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Data of turbulence, net radiation and temperature profiles obtained in International Energy Balance Experiment (EBEX-2000) are used to study characteristics of turbulence cospectra, temperature profiles and turbulent fluxes at 8.7 m and 2.7 m in the atmospheric surface layer. Interaction of large eddies with local turbulence in a disturbed surface layer induced by patch-to-patch irrigation is emphasized, as well as their influence on turbulent fluxes. Results indicate that peak frequencies of cospectra in the low frequency range at the two levels are well consistent, revealing that low frequency turbulence obeys the OLS law. High frequency turbulence obeys the local isotropy theory. Spectral energy in low frequency range is greatly enhanced by large eddies, and this enhancement is more notable at 8.7 m than that at 2.7 m. Multiple peak frequencies are observed at low frequency range of cospectra, and their scales correspond well with thermal heterogeneous scale of the underlying surface. Three dominant scales of these large eddies are 800, 400 and 200 m. Furthermore, large eddies have greater influence on turbulence at higher levels than lower levels and in unstable atmospheric surface layer than stable atmospheric surface layer.

A Study of Turbulent Heat Flux Corrections and Energy Balance Closure Problem on the Surface Layer in EBEX-2000

JIANG Haimei,LIU Shuhua,ZHANG Lei,LIU Heping

2013, 49(3):  443-451. 

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Data of EBEX-2000 was used to analyze the influences of Schotanus correction and Webb correction on turbulent heat fluxes and the governing factors of the two corrections. Furthermore, considering turbulent heat flux corrections, impact factors of energy balance ratio (EBR) were discussed and reasonable interpretations were provided according to actual weather and topographic condition. Results show that the magnitude of Schotanus correction varies from ?40 to 2 W/m², with a significant diurnal variation, and the mean value of which is ?8 W/m². The two dominant factors of Schotanus correction are atmospheric stability and vertical gradient of water vapor. The magnitude of Webb correction varies from ?5 W/m² to 14 W/m² with a mean value of 1.8 W/m², which is much smaller than that of Schotanus correction. Webb correction is positive for daytime and negative for nighttime, and it is mainly affected by Bowen ratio and specific humidity, having little probability to reach a great value. EBR calculated using a 30 minutes average is about 0.63 with large diurnal variations and dispersion, and decreases rapidly with a sudden rise of soil water content.

Using CALPUFF for Near-Field Atmospheric Dispersion Simulation over Complex Terrain

ZHU Hao,ZHANG Hongsheng,CAI Xuhui,LI Fengju,LIU Xinjian

2013, 49(3):  452-462. 

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Based on data from a comprehensive atmospheric dispersion experiment of high temporal and spatial resolution over a complex hilly-valley area in Hunan province, the applicability of USEPA (United States Environmental Protection Agency) recommended guideline model CALPUFF (California Puff Model) in near field over complex terrain was investigated. Using diagnostic wind fields of different temporal resolutions and various dispersion schemes, the near-field concentration distributions under various meteorological conditions were simulated and compared with the observed tracer concentrations. The results show that using the measured turbulence profiles to calculate dispersion parameters can better simulate near-field concentration distributions. The modeling results can be improved if the fitted relationships between standard deviations of turbulent velocities and stability parameters are used instead of the default CALPUFF turbulence parameterization scheme. The modeling results are not sensitive to the temporal resolution of wind fields and dispersion schemes when the wind speed is high and wind direction is steady. However, under low and variable wind conditions, the 10 min wind field is needed to model the ground concentration distributions. The modeling results of measured turbulence scheme are higher than those of similarity scheme and closer to the observed values. Overall, CALPUFF modeling system can well simulate the near-field peak concentrations over this hilly-valley complex terrain by using either the hourly wind field and turbulent measurement or 10 min wind field and modified similarity scheme.

On the Motion and Mesoscale Surface Structure of a Squall Line on April 23, 2007 in Guangdong

WU Duochang,MENG Zhiyong

2013, 49(3):  463-470. 

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The movement and the mesoscale surface structure of a squall line on April 23, 2007 in Guangdong is explored based on observations. It is shown that the moving direction of the squall line is parallel to the contours of the 1000?500 hPa layer thickness and the low-level vertical wind shear in front of the squall line. Meanwhile, the motion of the squall line can be estimated by the sum of inversed low-level jet and mean flow in the 850?300 hPa layer as proposed by Corfidi. Typical mesoscale surface structure of a squall line is observed including convergence and divergence lines, prelows, storm highs and wake lows. There is strong convergence line at the leading edge and in the back part of the squall line, and strong divergence line corresponding to the precipitation areas. The storm highs are between the divergence line and the convergence line in front of the squall line but much closer to the former, while the wake lows are behind the convergence line in the back of the squall line. These features of Guangdong squall line are also compared with those of squall lines in America.

Carnian (Late Triassic) Ammonoid Biostratigraphy in Luoping County, Eastern Yunnan Province, China

LI Yan,SUN Zuoyu,SUN Yuanlin,JIANG Dayong,HAO Weicheng

2013, 49(3):  471-479. 

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The present study is based on ammonoids collected from the strata above the ammonoid Trachyceras multituberculatum zone of Wayao Member of “Falang Formation” (Late Triassic) at the Niubudai Section in Luoping County, Eastern Yunnan Province. Eight species of four genera, including one conform species and three indeterminate species were recognized, among which Trachyceras aonoides, Simonyceras simonyi are firstly found in China. According to their assemblage and stratigraphic distribution, two ammonoid zones were recognized in ascending order: Trachyceras aonoides Zone, Austrotrachyceras triadicum Zone, corresponding to the middle-late Early Carnian of Late Triassic in age.

Implementation of Algorithms for Triangle Meshes Simplification for Huge 3D Geoscience Models

LIU Yiqin,PAN Mao,YANG Xukun

2013, 49(3):  480-484. 

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To satisfy the functional requirements of huge geoscience model visualization, a triangle mesh simplification and restore algorithm is realized to support LOD (level of detail) scheme based on constrains of both topological rules and geoscience rules. A multi-resolution data structure required by the algorithm is introduced. The simplification and restore of triangle mesh are realized with the collapsible edges’ collapse and restore, in which the collapsibility is decided by the topological rules and geoscience rules in 3D geoscience models. Test results manifest that the algorithm can handle triangle meshes with good effect and high efficiency, and is able to support the LOD scheme.

A Model of Direction Calculation Based on Point Group Dividing

WEN Xue,TIAN Yuan,WU Yang,WAN Jiahuan,WANG Xingguang

2013, 49(3):  485-490. 

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A model of direction calculation based on point group dividing is proposed. This model quantitatively calculates the direction of spatial targets by dividing the point groups resulted from discretization of spatial targets. A case study is designed to verify the model. It can be concluded that the model is feasible and fairly efficient. It can meet the calculation requirements of geographical information systems and can support spatial data retrieval and query well.

A Multi-level Analysis of the Relationship between Delay of Gratification Trait and Vocational Delay of Gratification: The Moderating Role of Transactional Leadership

LIU Xiaoyan,HUANG Yunhui

2013, 49(3):  491-496. 

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The authors discussed the moderating role of transactional leadership between individuals' delay of gratification (DOG) and their vocational delay of gratification in career (VDOG). Several questionnaires were conducted on 227 employees and their 22 direct leaders. The multi-level analysis (HLM) shows that the employees’ DOG trait (level 2), together with the transactional leadership (level 2), will affect the employees’ VDOG. Specifically, under low-level transactional leadership, employees of high level delay DOG trait are reported more VDOG than those of low level DOG trait, while under high-level transactional leadership, employees of both high and low level delay of gratification are reported high VDOG.

A Bibliometric Analysis of Incinerator Research during the Period 1991?2010

YUAN Li,LIU Yangsheng

2013, 49(3):  530-536. 

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A bibliometric analysis of incinerator research was conducted to evaluate the current trends, using the literatures in the Science Citation Index (SCI) database for the period 1991-2010. Articles were concentrated on the analysis by the document type, language, publication output, distribution of journals, the publication activity of countries and institutes, as well as keywords. The trend of publication outputs during 1991-2010 coincides with a exponential function model. English-language articles take the majority of all the publications. Incinerator research is primarily published in subject category of Environmental sciences, and Chemosphere is the most productive jour- nal with a number of publications of 344. The USA is the largest contributor of the total publications. While, China enjoys the highest growth rate in terms of publication over time. Finally, author keywords were analyzed to provide research emphasis. The results show that heavy metals, fly ash and dioxins were considered recent research hotspots. The generation of secondary pollutants can be effectively controlled by improved incinerator. Large-scale incineration equipment, such as grate incinerators and fluidized bed incinerators, will play a very important role in Chinese waste treatment in the future.

Online Measurement of PAN and PPN in Shanghai during the World Expo, 2010

HAN Li,ZHANG Jianbo,WANG Feng

2013, 49(3):  497-503. 

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Online measurement and analysis were taken for PAN and PPN during the 2010 World Expo in Pudong New District, Shanghai. The highest concentration were 5500 pptv and 709 pptv, respectively. PAN was higher in the month of May and June than that in July and August. The diurnal variations for PAN and PPN changed significantly, the lowest concentration occurred at 6:00 and the highest value occurred at 12:00. The ratio between PAN and PPN in July, August and October was lower than that in the other months, indicating that the maganitude of the anthropogenic VOCs declined. Average ratio of daily maximum PAN and O₃ was 0.034 with 93.4% ratio lower than 0.07, which was smaller than the typical urban ratio value.

Research on Biomass, Activity and Performance of Up-Flow BAC Filtration System

CHANG Chih-Hsiang,LIAO Xiaobin,ZHANG Xiaojian,CHEN Chao,XIE Shuguang

2013, 49(3):  504-508. 

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The spatial distribution of microbial biomass and activity in pilot-scale two-stage up-flow BAC filters were studied using lipid-P, plate colony count (HPC) and specific oxygen uptake rate (SOUR). Meanwhile, water qualities of the effluent were analyzed to evaluate the performance of BAC units. The results indicated that BAC filters could remove pollutants effectively, with the average removal efficiencies of 43.3 % for COD_Mn, 45.7% for UV₂₅₄, and 92.9 % for ammonia nitrogen, respectively. Furthermore, the removal of pollutants mainly occurred in of the top 400-mm GAC layer in the first-stage BAC filter. The content of lipid-P per unit volume media decreased from 7.49 to 4.86 nmol/cm³ and colony counts decreased from 2.26×10⁷ to 1.12×10⁷ CFU/cm³, indicating that the amount of biomass decreased along flow path. The SOUR per unit volume media was around 10^-2 mg / (cm³?h) and had a different pattern of spatial distribution. In addition, the water quality of the effluent of up-flow BAC filters was biologically safe.

Research on Rural Environmental Problems with either Strong Externalities or Weak Externalities and Corresponding Management Methods

HU Xuan,LI Lili,LUAN Shengji,SHEN Chen

2013, 49(3):  509-513. 

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Based on differences of externalities’ reaches, rural environment problems are categorized into two major types: environment problems with weak externalities and those with strong externalities. These two types of environmental problems need to be managed through different approaches. The authors argue that rural environment problems with weak externalities should be solved by internal cooperation within small groups, while rural environmental problems with strong externalities should be solved by supervision that imposes outside rewards and punishments on small groups.

Study on Adsorption Behavior of Pb²⁺ and Cd²⁺ by Extracellular Polymeric Substances

ZHANG Jiangshui,LIU Wen,SUN Weiling,XU Nan,NI Jinren

2013, 49(3):  514-522. 

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As a kind of new biosorbent, aerobic granular sludge which has the advantages of strong adsorption capacity and easily-desorbing property, was paid great attention in the area of heavy metal waste water treatment. In this research, the adsorption behaviors of Pb²⁺ and Cd²⁺ by extracellular polymeric substances (EPS) which extracted from aerobic granular sludge using improved centrifugation methods were studied. The results showed that the adsorption capacity of Pb²⁺ and Cd²⁺ on EPS was considerably large. The experimental results were fit well with the Langmuir iostherms model. The maximum adsorption capacity for Pb²⁺ and Cd²⁺ by EPS was up to 534.76 mg/g and 478.47 mg/g, respectively. Furthermore, the competitive adsorption experiments presented that EPS exhibited a selective adsorption for Pb²⁺. Specially, there was a minor inhibition for Pb²⁺ adsorption in presences of Cd²⁺, while the adsorption capacity of Cd²⁺ was greatly decreased when Pb²⁺ co-existed in solutions. FT-IR and EEM analysis revealed that EPS was rich in hydrophilic groups and hydrophobic groups, which was benefit to combine heavy metals by complexation, ions exchange and chelation. The adsorption of Pb²⁺ and Cd²⁺ by EPS was mainly attributed to the ?COOH, ?NH2, ?CH, ?OH and ?C=O groups from protein fractions of them. The main adsorption mechanism of Pb²⁺ by EPS was ion exchange and complexation, while for Cd²⁺ was mainly took effect by complexation.

Multi-simulation of Spatial Distribution of Land Use Based on CLUE-S Model: A Case Study of Yuzhong County, Gansu Province

XU Yueqing,LUO Ding,GUO Hongfeng,ZHOU Dong

2013, 49(3):  523-529. 

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Taking Yuzhong County of Gansu Province as a case study, based on land-use data in 1996, the authors adopted CLUE-S model to simulate land-use distribution in 2008 at the basic grid level (200 m×200 m), with the Kappa index 0.82. Then three scenarios of land-use spatial allocation in Yuzhong County in 2020, namely, farmland protection scenario, economic-oriented scenario and ecologically-oriented scenario, were established through designing different restrictions on land-use transition when running CLUE-S model in GIS environment. The results show that the scenario schemes have strongly influence on land-use distribution. Under farmland protection scenario, the farmland keep higher stability and tend to concentrated distribution characteristics. Arable land transition mainly occur in the north of the county and transit into grassland and forestland. While under economic-oriented scenario, construction land mainly distribute in Yuzhong Basin, where has better geological conditions. Ecological land such as farmland, grassland and forestland, take on characteristics under ecolo- gically-oriented scenario. Therefore, CLUE-S model is a powerful tool to simulate land-use spatial distribution of Yuzhong County, which provides a scientific basis for land-use planning and urban planning in the future.

Review of Optical Remote Sensing Imaging Simulation of Farmland Radiation Transfer Process

YANG Guijun,LIU Qinhuo,DU Yongming,SHI Yuechan,FENG Haikuan,WANG Jihua

2013, 49(3):  537-544. 

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The major methods of optical remote sensing imaging simulation which including optical physics simulation, image synthesis, computer graphics and remote sensing physical model method were introduced and analyzed. In particular, remote sensing physical model method has become main development trends because it can consider the truth of radiative transfer process. The key problems of cropland information time series simulation, the development of farmland radiative transfer models and remote sensing imaging simulation system were further discussed. The result shows that radiative transfer models of leaf, soil, canopy, atmosphere and sensor are integrated with the field observation information, e.g. canopy structure and spectral, to simulate multi-dimension remote sensing data for application requirements in agriculture quantitative remote sensing.

Key Recovery Attack on Hybrid Cipher SCB Algorithm

ZHANG Kai,GUAN Jie,ZHANG Zhongya,LUO Lei

2013, 49(3):  397-403. 

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According to the flaws in the design of the stream cipher part of SCB (senior cross breed) algorithm, the initial key could be recovered with the computational complexity of O(2⁴⁴) if the key stream of the stream cipher was known. To acquire the keystream of the stream cipher, a differential fault attack was proposed by using word oriented fault model for one bit random fault. When 640 faults were induced, the success rate could achieve 99.4%. The computational complexity to recover the 256 bit key was O(2⁴⁴).

Human and Vehicle Classification Method for Complex Scene Based on Multi-granularity Perception SVM

WU Jinyong,ZHAO Yong,WANG Yike,YUAN Yule,ZHANG Xing

2013, 49(3):  404-408. 

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For solving the problem of human and vehicles classification in complex scene, a novel method based on multi-granularity perception SVM (support vector machine) is proposed. Firstly, motion regions of the video are detected and analyzed, and visual perception information is extracted by corner detection in motion regions. In order to reduce the noise interference, perception information is inferenced by Kalman filter in time-space domain. Furthermore, multi-granularity perception features of objects are constructed with the mass center of motion regions. Finally, a two-level SVM classifier is constructed, and classification results are obtained by training and classifying on the SVM classifier with multi-granularity perception features vector set. The results of experimentation show that the proposed method is good. The average correct rate of all-day classification between human and vehicles is up to 93.6% separately, and it is valid to avoid the influence of illumination, colors and object’s size variation. It is suitable for intelligent traffic system.