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Error analysis on heading determination via genetic algorithms

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Journal of Systems Engineering and Electronics 2006年第3期17卷 673-676页

作者： Zhong Bing Xu Jiangning ma heng Dept. of Electric Naval Univ. of Engineering Wuhan 430033 P. R. China

A new error analysis method is presented via genetic algorithms for high precise heading determination model based on two total positioning stations （TPSs）. The method has the ability to search all possible solution space by the genetic operators of elitist model and restriction. The result of analyzing the error of this model shows that the accuracy of this model is precise enough to meet the need of calibration for navigation systems on ship, and the search space is only 0. 03% of the total search space, and the precision of heading determination is 4＂ in a general dock.

关键词： heading determination SGA genetic algorithms.

What determines irrigation efficiency when farmers face extreme weather events? A field survey of the major wheat producing regions in China

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Journal of Integrative Agriculture 2018年第8期17卷 1888-1899页

作者： SONG Chun-xiao Les Oxley ma heng-yun College of Economics and management Henan Agricultural University Department of Economics and Finance University of Waikato

Water availability is a major constraint on grain production in China, therefore, improving irrigation efficiency is particularly important when agriculture faces extreme weather events. This paper first calculates irrigation efficiency with a translog stochastic frontier production function and then investigates what happens when extreme weather events occur via a Tobit model. The estimated results reveal several important features of irrigation practices: i) irrigation efficiency is lower when extreme weather events occur; ii) large variations in irrigation efficiency occur across irrigation facilities; iii) the farm plots exhibit an extreme distribution across efficiency levels; and iv) water-saving techniques, technology adoption, and the maintenance of farmers’ economic resilience are major determinants of irrigation efficiency. Based on these results we propose the following recommendations: i) farmers should balance crop yield and water use; undertake relevant training programs and adopt water-saving techniques; ii) local governments and researchers should help farmers to find the optimal level of irrigation water use based on their own circumstances and provide better water-saving techniques and training programs rather than simply encouraging farmers to invest in irrigation facilities in the most extreme weather years; and iii) the income level of farm households should be increased so as to improve their resilience to natural disasters.

关键词： irrigation efficiency determinants irrigation facilities water-saving techniques extreme weather events

An INS/GNSS integrated navigation in GNSS denied environment using recurrent neural network

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Defence Technology（防务技术） 2020年第2期16卷 334-340页

作者： Hai-fa Dai Hong-wei Bian Rong-ying Wang heng ma Navigation Engineering Lab Naval Engineering UniversityWuhanCO430033China

In view of the failure of GNSS signals,this paper proposes an INS/GNSS integrated navigation method based on the recurrent neural network(RNN).This proposed method utilizes the calculation principle of INS and the memory function of the RNN to estimate the errors of the INS,thereby obtaining a continuous,reliable and high-precision navigation *** performance of the proposed method is firstly demonstrated using an INS/GNSS simulation ***,an experimental test on boat is also conducted to validate the performance of the *** results show a promising application prospect for RNN in the field of positioning for INS/GNSS integrated navigation in the absence of GNSS signal,as it outperforms extreme learning machine(ELM)and EKF by approximately 30%and 60%,respectively.

关键词： Inertial navigation system(INS) Global navigation satellite system(GNSS) Integrated navigation Recurrent neural network(RNN)

Porosity and permeability variations of a dam curtain during dissolution

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Water Science and Engineering 2019年第2期12卷 155-161页

作者： Ji-xiang Huo Fu-heng ma Xiao-lei Ji State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Nanjing Hydraulic Research InstituteNanjing 210029China College of Construction Engineering Jiangsu Open UniversityNanjing 210019China

During reservoir operation,the erosion effects of groundwater change the porosity and permeability of the dam curtain,causing changes to the seepage *** understand where the changes take place and to what degree the porosity and permeability change,a multi-field coupling model was built and *** model takes into account seepage,solution concentration,and solid *** model was validated using uplift pressure monitoring ***,the variations in curtain porosity,seepage flow,and loss quantity of Ca(OH)2 were *** key time nodes were obtained through curve fitting of the variation of seepage flow with the BiDoseResp *** results showed that the model could reflect the attenuation trend of curtain performance *** process and position of the erosion were not *** erosion mainly occurred at the top and bottom of the curtain,it was most developed at the *** erosion effects developed slowly during the early stage,much fast during the middle and late stages,and culminated in complete *** model results and the daily monitoring data can provide a scientific basis for the safe operation and management of reservoirs.

关键词： Dam curtain Permeability Multi-field coupling model Porosity Erosion Solute transport Seepage flow

Dealloying-derived nanoporous deficient titanium oxide as high-performance bifunctional sulfur host-catalysis material in lithium-sulfur battery

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Journal of materials Science & Technology 2021年第25期84卷 124-132页

作者： Ning Liu heng ma Lu Wang Yan Zhao Zhumabay Bakenov Xin Wang School of materials Science and Engineering Tianjin Key Laboratory of Materials Laminating Fabrication and Interface Control TechnologyHebei University of TechnologyTianjin 300130China Institute of Batteries LLC Department of Chemical and Materials EngineeringNational Laboratory AstanaNazarbayev University53 Kabanbay Batyr AvenueNur-Sultan 010000Kazakhstan South China Academy of Advanced Optoelectronics International Academy of Optoelectronics at ZhaoqingSouth China Normal UniversityGuangzhou 510006China

In this work,we report a facile dealloying strategy to tailor the surface state of nanoporous TiO_(2) towards high-efficiency sulfur host material for lithium-sulfur(Li-S)*** used as a sulfur cathode material,the oxygen-deficient TiO_(2)-xexhibits enhanced lithium polysulfides(Li PS)adsorption and conversion kinetics that effectively tackle the shuttle effect in lithium-sulfur *** excellent ability of the oxygen vacancy sites on TiO_(2)-xsurface to trap Li PS is proved by experimental observations and density functional theory(DFT)***,it also promotes conversion kinetics of lithium polysulfides,as verified by the asymmetric cell ***,compared with the S/TiO_(2) cathode,the oxygen-deficient S/TiO_(2)-xelectrode exhibits preeminent rate and cycling performance in lithium-sulfur batteries:it delivers an ultra-low capacity decay of 0.039%per cycle after 1000 cycles at 1 *** the surface state of metal oxides by dealloying method offers a new facile strategy to design efficient sulfur cathode materials for lithium-sulfur batteries.

关键词： Li-S battery Oxygen defects TiO_(2)-x Dealloying Cathode

A Modified Potential Method for Electrons Scattering Total Cross Section Calculations on Several Molecules at 30 ～ 5000 eV： CF4, CCl4, CFCl3, CF2Cl2, and CF3Cl

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Communications in Theoretical Physics 2006年第4期45卷 697-701页

作者： ma heng SHI De-heng SUN Jin-Feng LIU Yu-Fang ZHU Zun-Lue Department of Physics Henan Normal University Xinxiang 453007 China Department of Foundation the First Aeronautical College of Air Force Xinyang 464000 China

A complex optical model potential modified by the concept of bonded atom, which takes into consideration the overlapping effect of electron clouds between two atoms in a molecule, is employed to calculate the total cross sections （TCS5） for electrons scattering from several molecules （CF4, CCl4, CFCl3, CF2 Cl2, and CF3 Cl） over an incident energy range 30 - 5000 eV using the additivity rule model at Hartre-Fock level. The quantitative TCS5 are compared with those obtained by experiments and other theories wherever available, and good agreement is obtained above 100 eV. It is shown that the modified potential can successfully calculate the TCS5 of electron-molecule scattering over a wide energy range, especially at lower energies.

关键词： total cross section additivity rule atomic and molecular collision

A review of microfluidic approaches for investigating cancer extravasation during metastasis

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Microsystems & Nanoengineering 2018年第1期4卷 400-412页

作者： Yu-heng Vivian ma Kevin Middleton Lidan You Yu Sun Institute of Biomaterials and Biomedical Engineering University of Toronto164 College StreetRoom 407TorontoON M5S 3G9Canada Department of Mechanical and Industrial Engineering University of Toronto5 King’s College RoadRoom 105TorontoON M5S 3G8Canada

Metastases,or migration of cancers,are common and severe cancer *** the 5-year survival rates of primary tumors have greatly improved,those of metastasis remain below 30%,highlighting the importance of investigating specific mechanisms and therapeutic approaches for *** devices have emerged as a powerful platform for drug target identification and drug response screening and allow incorporation of complex interactions in the metastatic microenvironment as well as manipulation of individual *** this work,we review microfluidic devices that have been developed to study cancer cell migration and extravasation in response to mechanical(section‘Microfluidic investigation of mechanical factors in cancer cell migration’),biochemical(section‘Microfluidic investigation of biochemical signals in cancer cell invasion’),and cellular(section‘Microfluidic metastasis-on-a-chip models for investigation of cancer extravasation’)*** highlight the device characteristics,discuss the discoveries enabled by these devices,and offer perspectives on future directions for microfluidic investigations of cancer metastasis,with the ultimate aim of identifying the essential factors for a‘metastasis-on-a-chip’platform to pursue more efficacious treatment approaches for cancer metastasis.

关键词： biochemical signal cancer cell migration cancer cell extravasation metastasis-on-a-chip cellular signal microfluidic mechanical signal

Do farmers care about climate change? Evidence from five major grain producing areas of China

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Journal of Integrative Agriculture 2019年第6期18卷 1402-1414页

作者： SONG Chun-xiao LIU Rui-feng Les Oxley ma heng-yun College of Economics and management Henan Agricultural UniversityZhengzhou 450002P.R.China Department of Economics and Finance University of WaikatoHamilton 3240New Zealand

Using a logistic model,this paper empirically investigated farmers’perception of climate change and its determinants based on a field survey of 1 350 rural households across five major grain producing provinces in *** results show:i)There is an apparent difference in perception levels for long-term temperature and precipitation ***,57.4%of farmers perceived the long-term temperature change correctly,but only 29.7%of farmers perceived the long-term precipitation change correctly;ii)The factors influencing the farmers’perceptions are almost completely different between precipitation and temperature,the former are mostly agriculture related,while latter are mostly non-agriculture related,except for farm size;and iii)Farmers are not expected to pay more attention to long-term precipitation changes over the crop growing seasons,because less than 30%of farmers can correctly perceive long-term precipitation ***,to improve the accuracy of farmers’perceptions of climate change,the government is recommended to:i)enhance education and training programs;ii)speed up land transfer and expand household land farm size;iii)develop farmer cooperative organizations;iv)invest more in agricultural infrastructure,specifically in major grain producing regions;and v)improve the agricultural environment and increase farming income.

关键词： China major grain producing areas determinants climate change perception irrigation areas

Effect of hydrogen annealing on characteristics of polycrystalline silicon

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Rare Metals 2006年第Z1期25卷 173-175页

作者： GOU Xianfang XU Ying LI Xudong heng Yang ma Lifen REN Bingyan Beijing Solar Energy Research Institute Beijing 100083 China Beijing Solar Energy Research Institute Beijing 100083 China Beijing Solar Energy Research Institute Beijing 100083 China Beijing Solar Energy Research Institute Beijing 100083 China Beijing Solar Energy Research Institute Beijing 100083 China Institute of Information Function Materials Hebei University of Technology Tianjin 300130 China

The characteristics of mc-Si used for solar cells during H2 ambient annealing at 800-1200 ℃ were investigated by means of FTIR and QSSPCD. The results reveal that grain boundaries or defects in mc-Si may facilitate the formation of oxygen precipitates, and the formation of oxygen precipitates has deleterious effect on the lifetime of mc-Si. Decreasing lifetime could result from the formation of new recombination during annealing. Additionally, It is found that hydrogen may facilitate the formation of oxygen precipitates in mc-Si. On the other hand, the diffusion of hydrogen may passivate the defects/boundaries and it is beneficial to the lifetime of mc-Si.

关键词： multi-crystalline silicon oxygen and carbon minority carrier lifetime annealing