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Growth simulation and yield prediction for perennial jujube fruit tree by integrating age into the WOFOST model

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Journal of Integrative Agriculture 2020年第3期19卷 721-734页

作者： BAI Tie-cheng WANG Tao ZHANG nan-nan chen You-qi Benoit MERCATORIS TERRA Teaching and Research Centre Gembloux Agro-Bio TechLiège UniversityGembloux 5030Belgium Southern Xinjiang Research Center for Information Technology in Agriculture/College of Information Engineering Tarim UniversityAlaer 843300P.R.China Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural SciencesBeijing 100081P.R.China

Mathematical models have been widely employed for the simulation of growth dynamics of annual crops,thereby performing yield prediction,but not for fruit tree species such as jujube tree(Zizyphus jujuba).The objectives of this study were to investigate the potential use of a modified WOFOST model for predicting jujube yield by introducing tree age as a key *** model was established using data collected from dedicated field experiments performed in *** growth dynamics of dry weights of leaves,stems,fruits,total biomass and leaf area index(LAI) agreed well with measured values,showing root mean square error(RMSE) values of 0.143,0.333,0.366,0.624 t ha^-1 and 0.19,and R2 values of 0.947,0.976,0.985,0.986 and 0.95,*** phenological development stages for emergence,anthesis and maturity were 2,3 and 3 days earlier than the observed values,*** addition,in order to predict the yields of trees with different ages,the weight of new organs(initial buds and roots) in each growing season was introduced as the initial total dry weight(TDWI),which was calculated as averaged,fitted and optimized values of trees with the same *** results showed the evolution of the simulated LAI and yields profiled in response to the changes in *** modelling performance was significantly improved when it considered TDWI integrated with tree age,showing good global(R2≥0.856,RMSE≤0.68 t ha^-1) and local accuracies(mean R2≥0.43,RMSE≤0.70 t ha^-1).Furthermore,the optimized TDWI exhibited the highest precision,with globally validated R2 of 0.891 and RMSE of 0.591 t ha^-1,and local mean R2 of 0.57 and RMSE of 0.66 t ha^-1,*** proposed model was not only verified with the confidence to accurately predict yields of jujube,but it can also provide a fundamental strategy for simulating the growth of other fruit trees.

关键词： fruit tree growth simulation yield forecasting crop model tree age

Controlled fabrication of Pr(OH)_3 nanowires for enhanced photocatalytic activities

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Journal of Rare Earths 2019年第1期37卷 60-67,M0004页

作者： nan chen Adnan Younis Dewei Chu Sean Li School of Materials Science and Engineering University of New South Wales

In this report, praseodymium hydroxide Pr(OH)_3 nanowires with different aspect ratios (length to diameter ratios) were synthesized by a facile hydrothermal approach. The variations in alkali concentration during synthesis are found to form different aspect ratios of nanowires. The X-ray diffraction and Raman spectroscopy analysis demonstrate the absence of any impurity phases in as-prepared ***, photocatalytic activities of as-prepared nano wires were evaluated by the degradation of methyl orange (MO). Our findings reveal that the nanowires with larger aspect ratios have higher photocatalytic efficiency than the smaller aspect ratio samples. X-ray photospectroscopy investigations reveal that the samples with higher aspect ratio are found to exhibit more oxygen vacancies as compared to lower aspect ratio samples. The enhanced photocatalytic activities can be attributed to the presence of higher percentage of active crystal facet (100), higher concentration of defects densities and narrower band gap. Thus, Pr(OH)_3 nanowires can be considered as a potential candidate for the application of wastewater treatment and related technologies.

关键词： Praseodymium hydroxide nanowires Photocatalyst Rare earths

Global aerodynamic design optimization based on data dimensionality reduction

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Chinese Journal of Aeronautics 2018年第4期31卷 643-659页

作者： Yasong QIU Junqiang BAI nan LIU chen WANG School of Aeronautics Northwestern Polytechnical University Xi'an 710072 China A VIC Aerodynamics Research Institute Shenyang 110034 China

In aerodynamic optimization, global optimization methods such as genetic algorithms are preferred in many cases because of their advantage on reaching global optimum. However,for complex problems in which large number of design variables are needed, the computational cost becomes prohibitive, and thus original global optimization strategies are required. To address this need, data dimensionality reduction method is combined with global optimization methods, thus forming a new global optimization system, aiming to improve the efficiency of conventional global optimization. The new optimization system involves applying Proper Orthogonal Decomposition（POD） in dimensionality reduction of design space while maintaining the generality of original design space. Besides, an acceleration approach for samples calculation in surrogate modeling is applied to reduce the computational time while providing sufficient accuracy. The optimizations of a transonic airfoil RAE2822 and the transonic wing ONERA M6 are performed to demonstrate the effectiveness of the proposed new optimization system. In both cases, we manage to reduce the number of design variables from 20 to 10 and from 42 to 20 respectively. The new design optimization system converges faster and it takes 1/3 of the total time of traditional optimization to converge to a better design, thus significantly reducing the overall optimization time and improving the efficiency of conventional global design optimization method.

关键词： Aerodynamic shape design optimization Data dimensionality reduction Genetic algorithm Kriging surrogate model Proper orthogonal decomposition

Finite-Time Neural Funnel Control for Motor Servo Systems with Unknown Input Constraint

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Journal of Systems Science & Complexity 2017年第3期30卷 579-594页

作者： chen Qiang TANG Xiaoqing nan Yurong REN Xuemei College of Information Engineering Zhejiang University of Technology School of Automation Beijing Institute of Technology

In this paper, a finite-time neural funnel control(FTNFC) scheme is proposed for motor servo systems with unknown input constraint. To deal with the non-smooth input saturation constraint problem, a smooth non-affine function of the control input signal is employed to approximate the saturation constraint, which is further transformed into an affine form according to the mean-value theorem. A fast terminal sliding mode manifold is constructed by using a novel funnel error variable to force the tracking error falling into a prescribe boundary within a finite time. Then, a simple sigmoid neural network is utilized to approximate the unknown system nonlinearity including the *** from the prescribed performance control(PPC), the proposed finite-time neural funnel control avoids using the inverse transformed function in the controller design, and could guarantee the prescribed tracking performance without knowing the saturation bounds in prior. The effectiveness and superior performance of the proposed method are verified by comparative simulation results.

关键词： Funnel control input constraint neural network servo system.

A comparison of the toxicity of landfill leachate exposure at the seed soaking and germination stages on Zea mays L.(maize)

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Journal of Environmental Sciences 2017年第5期29卷 206-213页

作者： Guangke Li Junyan chen Wei Yan nan Sang College of Environment and Resource Shanxi University Taiyuan 030006 China

To compare the toxicity of landfill leachate exposure at the early stages of seed soaking and germination on maize,a field experiment was conducted to evaluate the physiological aspects of growth,yield and potential clastogenicity of root-tip cells. The maizes were treated with leachate at levels of 2%,10%,20%,30% or 50%（V/V）. First,the change of physiological indexes,including chlorophyll（Chl）,Malondialdehyde（MDA）and Reactive oxygen species（ROS）levels,combined with yield all showed that soaking with leachate,but not germination,generated a greater ecological risk on maize. After a soaking treatment of maize with 50% leachate,the Chl,MDA and ROS levels during a vigorous growth period were 47.3%,149.8% and 309.7%,respectively,of the control,whereas the yield decreased to 68.6% of the control. In addition,our results demonstrated that the leachate at lower levels could promote growth. This is mainly embodied in that the yield of maize treated with 10%leachate at the soaking stage increased to 116.0% of the control. Moreover,the cytological analysis experiment also demonstrated that the ecological risk of leachate still exists in both cases. Furthermore,the gray relational analysis showed that the ear row number and tassel branch number were the major factors affecting the yield of maize treated with 50%leachate at the stages of soaking and germination,respectively. In general,these results are helpful in understanding the phytotoxicity of leachate,which provides additional reference data for risk assessment and management of leachate.

关键词： Landfill leachate Maize Phytotoxicity Seed soaking Germination

The structure,formation,and effect of plasma protein layer on the blood contact materials:A review

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Biosurface and Biotribology 2022年第1期8卷 1-14页

作者： Xiao chen Jiang chen nan Huang Institute of Biomaterials and Surface Engineering Key Lab.for Advanced Technologies of MaterialsMinistry of EducationSouthwest Jiaotong UniversityChengduChina

Understanding material-protein interactions is the basis for regulating material-blood interactions,which is a common topic of interest for medical material *** recent years,researchers have conducted extensive studies on(1)the structural charac-teristics of the plasma protein adsorption layer on the material surface,including the evolution of the protein adsorption layer and its typical binary structure.(2)Influence factors of the protein adsorption layer formation include protein factors(e.g.,isoelectric point,structural stability),material factors(e.g.,wettability,surface charge,morphology,size),and environmental factors.(3)Effects of some common plasma proteins in the protein adsorption layer on material-blood ***,we review the important research results in this field,hoping to provide a reference for future development of advanced blood contact materials.

关键词： blood contact material protein adsorption protein adsorption layer protein conformation plasma protein Vroman effect

Deep learning-based multi-source precipitation merging for the Tibetan Plateau

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Science China Earth Sciences 2023年第4期66卷 852-870页

作者： Tianyi nan Jie chen Zhiwei DING Wei LI Hua chen State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China Hubei Provincial Key Lab of Water System Science for Sponge City Construction Wuhan UniversityWuhan 430072China

Due to its complex and diverse terrain, precipitation gauges in the Tibetan Plateau(TP) are sparse, making it difficult to obtain reliable precipitation data for environmental studies. Data merging is a method that can integrate precipitation data from multiple sources to generate high-precision precipitation data. However, the more commonly used methods, such as regression and machine learning, do not usually consider the local correlation of precipitation, so that the spatial pattern of precipitation cannot be reproduced, while deep learning methods do incorporate spatial correlation. To explore the ability of using deep learning methods in merging precipitation data for the TP, this study compared three methods: a deep learning method—a convolutional neural network(CNN) algorithm, a machine learning method—an artificial neural network(ANN) algorithm, and a statistical method based on Extended Triple Collocation(ETC) in merging precipitation from multiple sources(gauged, grid,satellite and dynamic downscaling) over the TP, as well as their performance for hydrological simulations. Dynamic downscaling data driven by global reanalysis data centered on the TP were introduced in the merging process to better reflect the spatial variability of precipitation. The results show that:(1) in terms of the meteorological metrics, the merged data perform better than the gauge interpolation data. By using data merging, the error between the raw multi-source and gauged precipitation can be reduced, and the precipitation detection capability can be greatly improved;(2) The merged precipitation data also perform well in the hydrological evaluation. The Xin’anjiang(XAJ) model parameter calibration experiments at the source of the Yangtze River(SYR) and the source of the Yellow River(SHR) were repeated 300 times to remove uncertainty in the model parameter results. The median Kling-Gupta Efficiency Coefficients(KGE) of simulated runoff from the merged data of the ANN, CNN and ETC me

关键词： Tibetan Plateau Precipitation data merging Deep learning Dynamic downscaling

Thermokinetic　Oscillation　of　a　Two-step　Reacting　System　Coupled　with　Thermal　Conduction　and　Apparent

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Chemical Research in Chinese Universities 1998年第1期14卷 65-69页

作者： chen, Xiao-nan Luo, Jiu-li Sichuan Univ Dept Chem Chengdu 610064 Peoples R China

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关键词： Coupled Thermal Oscillation Apparent

Sporadic somatic mutation of c-kit gene in a family with gastrointestinal stromal tumors without cutaneous hyperpigmentation

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World Journal of Gastroenterology 2006年第11期12卷 1813-1815页

作者： Chun-nan Yeh Tsung-Wen chen Department of Surgery Chang Gung Memorial Hospital Chang Gung University 5Fu-Hsing StreetKwei-ShanTaoyuanTaiwanChina

We described two members in a family with gastrointestinal stromal tumors （GISTs） without cutaneous hyperpigmentation. The patients were father and son who did not have cutaneous hyperpigmentation. Histological examination showed that these tumors were GISTs expressing CD34 and CD117. Tumor DNA extracted from paraffin-embedded specimens revealed somatic mutation with a deletion mutation at different codons in exon 11 of c-kit gene after direct sequencing analysis. No germline mutation was detected in DNA extracted from peripheral leukocytes obtained from the father and son. We propose that GISTs could be caused by sporadic somatic mutation in a family without germline mutation and hyperpigmentation.

关键词： Sporadic GIST Somatic c-kit mutation