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Two New Multi-component BKP Hierarchies

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Communications in Theoretical Physics 2009年第2期51卷 193-199页

作者： WU Hong-Xia liu xiao-jun ZENG Yun-Bo Department of Mathematics School of Science Jimei University Xiamen China361021 Department of Mathematics China Agricultural University Beijing China100083 Department of Mathematical Sciences Tsinghua University Beijing China100084

We firstly propose two kinds of new multi-component BKP （mcBKP） hierarchy based on the eigenfunction symmetry reduction and nonstandard reduction, respectively. The first one contains two types of BKP equation with self-consistent sources whose Lax representations are presented. The two mcBKP hierarchies both admit reductions to the k-constrained BKP hierarchy and to integrable （1＋1）-dimensional hierarchy with self-consistent sources, which include two types of SK equation with self-consistent sources and of hi-directional SK equations with self-consistent

关键词： multi-component BKP hierarchy BKP equation with self-consistent sources κ-constrained BKPhierarchy n-reduction of mcBKP Lax representation

Solidification of loess using microbial induced carbonate precipitation

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Journal of Mountain Science 2021年第1期18卷 265-274页

作者： liu xiao-jun FAN Jin-yue YU Jing GAO Xin Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering College of Civil EngineeringXi'an University of Architecture and TechnologyXi'an 710055China College of Civil Engineering Xi'an University of Architecture and TechnologyXi'an 710055China

Microbial-induced carbonate precipitation(MICP)is a relatively innovative and environmentally-friendly soil reinforcement technology,primarily used on sand,but its application in loess has rarely been *** paper explores the viability of the MICP technique for improving the engineering properties of typical *** pasteurii was used to trigger carbonate *** such as reaction temperature,p H of the media,and the inoculation ratio were adopted to determine the optimum *** concentrations of Sporosarcina pasteurii and cementation reagent were selected for combination to treat the loess samples with a selfdesigned vacuum test *** unconfined compressive strength and calcium carbonate content of the treated samples were tested and Scanning Electron Microscopy(SEM)was carried out to evaluate the improving *** results showed that the optimum conditions are reaction temperature of 30℃,p H of the media of 9,a higher inoculation ratio can produce higher enzyme activity and monomer enzyme *** engineering properties of the MICP-treated loess are significantly *** obtained unconfined compressive strength increases nearly 4 times when the OD600 is 1.5 and cementation reagent concentration is 1 mol/*** test results of calcium carbonate content are consistent with unconfined compressive ***,the microstructure of loess samples was quantitatively analyzed by Pore(Particle)and cracks analysis system(PCAS).It was showed that MICP has a great influence on the surface porosity,followed by the pore fractal dimension and the probability entropy,but has little influence on the pore average form factor.

关键词： Loess solidification MICP Unconfined compressivestrength Calciumcarbonate Microstructure

Spatial and Temporal Characteristics of Rice Potential Productivity and Potential Yield Increment in Main Production Regions of China

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Journal of Integrative Agriculture 2013年第1期12卷 45-56页

作者： JIANG xiao-jian TANG Liang liu xiao-jun CAO Wei-xing ZHU Yan National Engineering and Technology Center for Information Agriculture Ministry of Industry and Information Technology/Key Laboratory for Information AgricultureScience and Technology Department of Jiangsu Province/College of AgricultureNanjing Agricultural University

The vast area and marked variation of China make it difficult to predict the impact of climate changes on rice productivity in different ***,analyzing the spatial and temporal characteristics of rice potential productivity and predicting the possible yield increment in main rice production regions of China is important for guiding rice production and ensuring food *** meteorological data of main rice production regions from 1961 to 1970（the 1960s） and from 1996 to 2005（the 2000s） provided by 333 stations,the potential photosynthetic,photo-thermal and climatic productivities in rice crop of the 1960s and 2000s in main rice production regions of China were predicted,and differences in the spatial and temporal distribution characteristics between two decades were ***,the potential yield increment based on the high yield target and actual yield of rice in the 2000s were *** with the 1960s,the potential photosynthetic productivity of the 2000s was seen to have decreased by 5.40%,with rates in northeastern and southwestern China found to be lower than those in central and southern *** potential photo-thermal productivity was generally seen to decrease（2.56%） throughout main rice production regions,decreasing most in central and southern ***,an increase was seen in northeastern and southwestern *** potential climatic productivity was observed to be lower（7.44%） in the 2000s compared to the 1960s,but increased in parts of central and southern *** potential yield increment from the actual yield to high yield target in the 2000s were no more than 6×103 kg ha-1 and ranged from 6×103 to 12×103 kg ha-1 in most of the single-and double-cropping rice growing regions,*** yield increasing potential from the high yield target to the potential photo-thermal productivity in 2000s were less than 10×103 kg ha-1 and ranged from 10×103 to 30×103 kg ha-1 in most of the single-and double-croppi

关键词： rice photosynthetic productivity photo-thermal productivity climatic productivity yield increment spatial and temporal distribution China

Influence of limited-view scanning on depth imaging of photoacoustic tomography

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Chinese Physics B 2012年第1期21卷 273-278页

作者： Wu Dan Tao Chao liu xiao-jun Wang Xue-Ding Key Laboratory of Modern Acoustics of Ministry of Education Nanjing UniversityNanjing 210093China Department of Radiology University of MichiganAnn ArborMichigan 48109USA

We study the influence of limited-view scanning on the depth imaging of photoacoustic tomography. The situation, in which absorbers are located at different depths with respect to the limited-view scanning trajectory, is called depth imaging and is investigated in this paper. The results show that limited-view scanning causes the reconstructed intensity of deep absorbers to be weaker than that of shallow ones and that deep absorbers will be invisible if the scanning range is too small. The concept of effective scanning angle is proposed to analyse that phenomenon. We find that an effective scanning angle can well predict the relationship between scanning angle and the intensity ratio of absorbers. In addition, limited-view scanning is employed to improve image quality.

关键词： photoacoustic tomography limited-view scanning depth imaging back-projection re-construction

Leaf area index based nitrogen diagnosis in irrigated lowland rice

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Journal of Integrative Agriculture 2018年第1期17卷 111-121页

作者： liu xiao-jun CAO Qiang YUAN Zhao-feng liu Xia WANG xiao-ling TIAN Yong-chao CAO Wei-xing ZHU Yan National Engineering and Technology Center for Information Agriculture Key Laboratory for Crop System Analysis and Decision Making Ministry of Agriculture/Jiangsu Key Laboratory for Information Agriculture/Jiangsu Collaborative Innovation Center forModern Crop Production/Nanjing Agricultural University Nanjing 210095 P.R. China

Leaf area index （LAI） is used for crop growth monitoring in agronomic research, and is promising to diagnose the nitrogen （N） status of crops. This study was conducted to develop appropriate LAI-based N diagnostic models in irrigated lowland rice. Four field experiments were carried out in Jiangsu Province of East China from 2009 to 2014. Different N application rates and plant densities were used to generate contrasting conditions of N availability or population densities in rice. LAI was determined by LI-3000, and estimated indirectly by LAI-2000 during vegetative growth period. Group and individual plant characters （e.g., tiller number （TN） and plant height （H）） were investigated simultaneously. Two N indicators of plant N accumulation （NA） and N nutrition index （NNI） were measured as well. A calibration equation （LAI=1.7787LAI2o00-0.8816, R2=0.870＂） was developed for LAI-2000. The linear regression analysis showed a significant relationship between NA and actual LAI （R2=0.863^＊＊）. For the NNI, the relative LAI （R2=0.808-） was a relatively unbiased variable in the regression than the LAI （R^2=0.33^＊＊）. The results were used to formulate two LAI-based N diagnostic models for irrigated lowland rice （NA=29.778LAI-5.9397; NNI=0.7705RLAI＋0.2764）. Finally, a simple LAI deterministic model was developed to estimate the actual LAI using the characters of TN and H （LAI=-0.3375（THxHx0.01）2＋3.665（TH×H×0.01）-1.8249, R2=0.875＊＊）. With these models, the N status of rice can be diagnosed conveniently in the field.

关键词： leaf area index rice LAI-2000 nitrogen diagnosis plant characters

Modeling curve dynamics and spatial geometry characteristics of rice leaves

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Journal of Integrative Agriculture 2017年第10期16卷 2177-2190页

作者： ZHANG Yong-hui TANG Liang liu xiao-jun liu Lei-lei CAO Wei-xing ZHU Yan Computer Engineering School Weifang University National Engineering and Technology Center for Information Agriculture/Key Laboratory for Crop System Analysis and Decision Making Ministry of Agriculture/Jiangsu Key Laboratory for Information Agriculture/Jiangsu Collaborative Innovation Center for Modern Crop Production/Nanjing Agricultural University

The objective of this work was to develop a dynamic model for describing leaf curves and a the rice leaf （including sub-models for unexpanded leaf blades, expanded leaf blades, and dimensional （3D） dynamic visualization of rice leaves by combining relevant models detailed spatial geometry model of leaf sheaths）, and to realize three- Based on the experimental data of different cultivars and nitrogen （N） rates, the time-course spatial data of leaf curves on the main stem were collected during the rice development stage, then a dynamic model of the rice leaf curve was developed using quantitative modeling technology. Further, a detailed 3D geometric model of rice leaves was built based on the spatial geometry technique and the non-uniform rational B-spline （NURBS） method. Validating the rice leaf curve model with independent field experiment data showed that the average distances between observed and predicted curves were less than 0.89 and 1.20 cm at the tilling and jointing stages, respectively. The proposed leaf curve model and leaf spatial geometry model together with the relevant previous models were used to simulate the spatial morphology and the color dynamics of a single leaf and of leaves on the rice plant after different growing days by 3D visualization technology. The validation of the leaf curve model and the results of leaf 3D visualization indicated that our leaf curve model and leaf spatial geometry model could efficiently predict the dynamics of rice leaf spatial morphology during leaf development stages. These results provide a technical support for related research on virtual rice.

关键词： rice morphological models leaf geometry characteristics virtual plant

Modeling Dynamics of Leaf Color Based on RGB Value in Rice

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Journal of Integrative Agriculture 2014年第4期13卷 749-759页

作者： ZHANG Yong-hui TANG Liang liu xiao-jun liu Lei-lei CAO Wei-xing ZHU Yan National Engineering and Technology Center for Information Agriculture Ministry of Industry and Information Technology/Jiangsu Key Laboratory for Information Agriculture/College of AgricultureNanjing Agricultural University

This paper was to develop a model for simulating the leaf color changes in rice （Oryza sativa L.） based on RGB （red, green, and blue） values. Based on rice experiment data with different cultivars and nitrogen （N） rates, the time-course RGB values of each leaf on main stem were collected during the growth period in rice, and a model for simulating the dynamics of leaf color in rice was then developed using quantitative modeling technology. The results showed that the RGB values of leaf color gradually decreased from the initial values （light green） to the steady values （green） during the first stage, remained the steady values （green） during the second stage, then gradually increased to the final values （from green to yellow） during the third stage. The decreasing linear functions, constant functions and increasing linear functions were used to simulate the changes in RGB values of leaf color at the first, second and third stages with growing degree days （GDD）, respectively; two cultivar parameters, MatRGB （leaf color matrix） and AR （a vector composed of the ratio of the cumulative GDD of each stage during color change process of leaf n to that during leaf n drawn under adequate N status）, were introduced to quantify the genetic characters in RGB values of leaf color and in durations of different stages during leaf color change, respectively; FN （N impact factor） was used to quantify the effects of N levels on RGB values of leaf color and on durations of different stages during leaf color change; linear functions were applied to simulate the changes in leaf color along the leaf midvein direction during leaf development process. Validation of the models with the independent experiment dataset exhibited that the root mean square errors （RMSE） between the observed and simulated RGB values were among 8 to 13, the relative RMSE （RRMSE） were among 8 to 10%, the mean absolute differences （da） were among 3.85 to 6.90, and the ratio of da to the mean observation values （Clap

关键词： rice leaf color RGB dynamic simulation visualization

Common Spectral Bands and Optimum Vegetation Indices for Monitoring Leaf Nitrogen Accumulation in Rice and Wheat

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Journal of Integrative Agriculture 2012年第12期11卷 2001-2012页

作者： WANG Wei YAO Xia TIAN Yong-chao liu xiao-jun NI jun CAO Wei-xing ZHU Yan National Engineering and Technology Center for Information Agriculture Ministry of Industry and Information Technology/Key Laboratory for Information AgricultureScience and Technology Department of Jiangsu Province/College of AgricultureNanjing Agricultural University

Real-time monitoring of nitrogen status in rice and wheat plant is of significant importance for nitrogen diagnosis, fertilization recommendation, and productivity prediction. With 11 field experiments involving different cultivars, nitrogen rates, and water regimes, time-course measurements were taken of canopy hyperspeetral reflectance between 350-2 500 nm and leaf nitrogen accumulation （LNA） in rice and wheat. A new spectral analysis method through the consideration of characteristics of canopy components and plant growth status varied with phenological growth stages was designed to explore the common central bands in rice and wheat. Comprehensive analyses were made on the quantitative relationships of LNA to soil adjusted vegetation index （SAVI） and ratio vegetation index （RVI） composed of any two bands between 350-2 500 nm in rice and wheat. The results showed that the ranges of indicative spectral reflectance were largely located in 770-913 and 729-742 nm in both rice and wheat. The optimum spectral vegetation index for estimating LNA was SAVI （R822, R738） during the early-mid period （from jointing to booting）, and it was RVI （Rs22, R73s） during the mid-late period （from heading to filling） with the common central bands of 822 and 738 nm in rice and wheat. Comparison of the present spectral vegetation indices with previously reported vegetation indices gave a satisfactory performance in estimating LNA. It is concluded that the spectral bands of 822 and 738 nm can be used as common reflectance indicators for monitoring leaf nitrogen accumulation in rice and wheat.

关键词： spectral band vegetation index leaf nitrogen accumulation (LNA) rice wheat

A New Method to Determine Central Wavelength and Optimal Bandwidth for Predicting Plant Nitrogen Uptake in Winter Wheat

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Journal of Integrative Agriculture 2013年第5期12卷 788-802页

作者： YAO Xin-feng YAO Xia TIAN Yong-chao NI jun liu xiao-jun CAO Wei-xing ZHU Yan National Engineering and Technology Center for Information Agriculture Ministry of Industry and Information Technology/Jiangsu Key Laboratory for Information AgricultureScience and Technology Department of Jiangsu Province/College of AgricultureNanjing Agricultural University

Plant nitrogen （N） uptake is a good indicator of crop N status. In this study, a new method was designed to determine the central wavelength, optimal bandwidth and vegetation indices for predicting plant N uptake （g N m-2） in winter wheat （Triticum aestivum L.）. The data were collected from the ground-based hyperspectral reflectance measurements in eight field experiments on winter wheat of different years, eco-sites, varieties, N rates, sowing dates, and densities. The plant N uptake index （PNUI） based on NDVI of 807 nm combined with 736 nm was selected as the optimal vegetation index, and a linear model was developed with R2 of 0.870 and RMSE of 1.546 g N m-2 for calibration, and R2 of 0.834, RMSE of 1.316 g N m-2, slope of 0.934, and intercept of 0.001 for validation. Then, the effect of the bandwidth of central wavelengths on model performance was determined based on the interaction between central wavelength and bandwidth expansion. The results indicated that the optimal bandwidth varies with the changes of the central wavelength and with the interaction between the two bands in one vegetation index. These findings are important for prediction and diagnosis of plant N uptake more precise and accurate in crop management.

关键词： central wavelength optimal bandwidth plant nitrogen uptake winter wheat