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Denoising of Chinese calligraphy tablet images based on run-length statistics and structure characteristic of character strokes

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第7期7卷 1178-1186页

作者： zhang jun-song YU Jin-hui MAO Guo-hong YE Xiu-zi State Key Lab of CAD ＆ CG Zhejiang University Hangzhou 310027 China School of Computer Sctence China University ofGeosciences Wuhan 430074 China

In this paper, a novel approach is proposed for denoising of Chinese calligraphy tablet documents. The method includes two phases: First, a partial differential equations (PDE) based the total variation model and Otsu thresholding method are used to preprocess the calligraphy document image. Second, a new method based on run-length statistics and structure charac- teristics of Chinese characters is proposed to remove some random and ant-like noises. This includes the optimal threshold se- lection from histogram of run-length probability density, and improved Hough transform algorithm for line shape noise detection and removal. Examples are given in the paper to demonstrate the proposed method.

关键词： Denoising Tablet images Structure characteristics Character strokes

A Novel Polarizer Made from Two-Dimensional Photonic Bandgap Materials

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Chinese Physics Letters 2001年第8期18卷 1082-1084页

作者： zhang Chun QIAO Feng WAN jun zi Jian National Key Laboratory of Surface Physics Fudan UniversityShanghai 200433

We demonstrate theoretically that two-dimensional photonic bandgap materials are indeed perfect polarizers provided that they have a proper photonic band structure along the incident direction of *** kind of polarizer is fundamentally different from the conventional *** can function in a wide frequency range with high performance and its size can be made very compact,which renders it useful as a micropolarizer in micro-optics.

关键词： polarizer Polar render

Centralized light-wave WDM-PON employing DQPSK downstream and OOK remodulated upstream signals

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The Journal of China Universities of Posts and Telecommunications 2010年第4期17卷 125-128页

作者： zhang Wei-feng XIN Xiang-jun zhang Qi zhang zi-xing NAI Wei SHI Yan School of Electronic Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

A novel architecture for wavelength-division-multiplexing passive optical network （WDM-PON） with centralized light-wave is proposed and demonstrated. At the optical line terminal （OLT） session of this architecture, optical differential quadrature phase shift keying （DQPSK） modulated signal with constant-intensity at 10 Gbit/s is utilized for downstream transmission. At the optical network unit （ONU）, part of the downstream optical power is remodulated with on-off keying （OOK） intensity modulation at 10 Gbit/s for upstream without additional laser. Simulation results show that the power penalties of the downstream for 20 km single-mode fiber （SMF） transmission and multi-channels are negligible. While for the upstream, the power penalties are obvious. The simulation results and analysis also reflect that by reducing the launch power of DQPSK transmitters, power penalties can be reduced, although the transmission distance is limited.

关键词： WDM-PON DQPSK remodulation centralizedlight sources

Iron-Catalyzed Amide Bond Formation from Carboxylic Acids and Isocyanates

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Chinese Journal of Chemistry 2023年第23期41卷 3268-3274页

作者： Lingjian zi Jing zhang The Institute for Advanced Studies Wuhan UniversityWuhanHubei430072 China

We describe an iron-catalyzed amide bond formation from readily available carboxylic acids and *** method utilizes an abundant and biocompatible iron catalyst and easily accessible starting materials,generates CO_(2) as the only byproduct,and features broad substrate scopes with good functional group ***,it provides a cost-effective and practical protocol to access a diverse variety of amides.

关键词： Iroen Carboxylic acids Amides C—N bond formation Rearrangement

Dilepton Distribution as a Signature for the Baryon-Rich Quark-Gluon Matter

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Chinese Physics Letters 1997年第8期14卷 577-580页

作者： HE Ze-jun zhang Jia-ju WANG zi-xing QIU Xi-jun CCAST(World Laboratory)P.O.Box 8730 Beijing 100080 Institute of Nuclear Research Chinese Academy of SciencesShanghai 201800 Computing Center Shanghai BranchChinese Academy of SciencesShanghai 200031

From the full stopping scenario,the dilepton production in the baryon-rich quark-gluon fireball based on a relativistic hydrodynamic model is studied,and it is found that with increasing incident energy a characterist... 详细信息

关键词： quark lepton relativistic

Propagation of shaped beam through uniaxially anisotropic chiral slab

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Chinese Physics B 2020年第11期29卷 380-385页

作者： Ming-jun Wang Jia-Lin zhang Hua-Yong zhang zi-Han Wang School of Automation and Information Engineering Xi’an University of TechnologyXi’an 710048China School of Electronics and Information Engineering Anhui UniversityHefei 230039China School of Chemistry and Chemical Engineering Anhui UniversityHefei 230039China School of Physics and Telecommunications Engineering Shaanxi University of TechnologyHanzhong 723001China

A general solution is obtained to a canonical problem of the reflection and refraction of an arbitrary shaped beam by using a uniaxially anisotropic chiral *** reflected,internal as well as refracted shaped beams are expanded in terms of cylindrical vector wave functions,and the expansion coefficients are determined by using the boundary conditions and method of moments *** two typical examples,the normalized field intensity distributions are evaluated for a fundamental Gaussian beam and Hermite-Gaussian beam,and some propagation properties,especially the negative refraction phenomenon,are discussed briefly.

关键词： shaped beam uniaxially anisotropic chiral slab reflection and refraction negative refraction phenomenon

The asymptotic relation between the first crossing point and the last exit time of Gaussian order statistics sequences

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Applied Mathematics(A Journal of Chinese Universities) 2023年第4期38卷 545-561页

作者： NING zi-jun TAN Zhong-quan College of Data Science Jiaxing UniversityJiaxing 314001China

In this paper,we study the asymptotic relation between the first crossing point and the last exit time for Gaussian order statistics which are generated by stationary weakly and strongly dependent Gaussian *** is shown that the first crossing point and the last exit time are asymptotically independent and dependent for weakly and strongly dependent cases,*** asymptotic relations between the first crossing point and the last exit time for stationary weakly and strongly dependent Gaussian sequences are also obtained.

关键词： rst crossing point last exit time stationary Gaussian sequences Gaussian order statistic se-quences

Degradation of Chlorpyrifos and Fipronil in Rice from Farm to Fork and Risk Assessment

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Agricultural Sciences in China 2010年第5期9卷 754-763页

作者： zhang Cun-zheng zhang Xin-ming TIAN zi-hua HE Dan-jun LIU Xian-jin Institute of Food Safety Jiangsu Academy of Agricultural Sciences/Key Laboratory of Food Safety Monitoring and Management Ministry of Agriculture/Key Lab of Food Quality and Safety of Jiangsu Province - State Key Laboratory Breeding Base Nanjing 210014 P.R. China Nanjing Centre of Inspection and Testing for Agricultural Products Ministry of Agriculture Nanjing 210036 P.R.China Nanjing Exit-Entry Inspection and Quarantine Bureau Nanjing 210003 P.R.China Taicang Centre of Inspection and Testing for Agricultural Products Taicang 215412 P.R.China

Degradation of pesticide residues （chlorpyrifos and fipronil） in rice from farm to fork and risk assessment for human health were studied to reveal the magnitude of risks faced by different populations of interest, so that appropriate measures can be taken to control the risks, and to refine and update the human health risk assessment data while helping to determine the maximum residue level （MRL） value and harvest interval. Different dosages and treatments were used in field trials for the harvest residue test. Residue levels of postharvest-applied chlorpyrifos and fipronil during storage, exposure to sunlight, washing and boiling processes （boiled rice） were investigated for brown rice. The dietary exposure evaluation model （DEEM） was employed to estimate acute and chronic risks faced by different populations of interest. Percent of reference dose （POR） and margin of exposure （MOE） were calculated. A positive correlation between pesticide residues and the dosage and application frequency of pesticide was found in the field trials. Risk quotients indicate that multiple applications and double dosages of chlorpyrifos increase the risks to the entire population and prolong exposures to toxic concentrations. The concentration of pesticide residues decreased as a function of time, after sunlight exposure, storage, washing, and boiling processes. 91.6 and 96.16% degradations were achieved at the end of the experimental period for fipronil and chlorpyrifos, respectively. The boiling process played an important role in the degradation of these pesticides. The result of risk assessment to human health showed that harvest residues of chlorpyrifos in rice and acute dietary risks of chlopyrifos were of concern. The acute dietary （food only） risk estimated for chlorpyrifos as percent of acute population adjusted dose （aPAD） was frequently over 100%. The risk faced by boys under the age of 14 was higher than that for girls of the same age. For the subpopulation above age 14, th

关键词： rice risk assessment pesticide residue chlorpyrifos fipronil

A multiobjective evolutionary optimization method based critical rainfall thresholds for debris flows initiation

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Journal of Mountain Science 2020年第8期17卷 1860-1873页

作者： YAN Yan zhang Yu HU Wang GUO Xiao-jun MA Chao WANG zi-ang zhang Qun Key Laboratory of High-Speed Railway Engineering MOE/School of Civil EngineeringSouthwest Jiao tong UniversityChengdu 610031China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China School of Computer Science and Engineering University of Electronic Science and Technology of ChinaChengdu 611731China Key Laboratory of Mountain Surface Process and Hazards/Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China School of Soil and Water Conservation Beijing Forestry UniversityBeijing 100083China Sichuan Institute of Land and Space Ecological Restoration and Geological Hazard Prevention Chengdu 610081China

At present,most researches on the critical rainfall threshold of debris flow initiation use a linear model obtained through *** relatively weak fault tolerance,this method not only ignores nonlinear effects but also is susceptible to singular noise samples,which makes it difficult to characterize the true quantization relationship of the rainfall ***,the early warning threshold determined by statistical parameters is susceptible to negative samples(samples where no debris flow has occurred),which leads to uncertainty in the reliability of the early warning results by the regression *** overcome the above limitations,this study develops a data-driven multiobjective evolutionary optimization method that combines an artificial neural network(ANN)and a multiobjective evolutionary optimization implemented by particle swarm optimization(PSO).Firstly,the Pareto optimality method is used to represent the nonlinear and conflicting critical thresholds for the rainfall intensity I and the rainfall duration *** ANN is used to construct a dual-target(dual-task)predictive surrogate model,and then a PSO-based multiobjective evolutionary optimization algorithm is applied to train the ANN and stochastically search the trained ANN for obtaining the Pareto front of the I-D surrogate prediction model,which is intended to overcome the limitations of the existing linear regression-based threshold ***,a double early warning curve model that can effectively control the false alarm rate and negative alarm rate of hazard warnings are proposed based on the decision space and target space *** study provides theoretical guidance for the early warning and forecasting of debris flows and has strong applicability.

关键词： Debris flow Critical rainfall thresholds Multiobjective evolutionary optimization Artificial neural network Pareto optimality