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Comprehensive Evaluation of Tobacco Ecological Suitability of Henan Province Based on GIS

Agricultural Sciences in China 2010年第4期9卷 583-592页

作者： CHEN Hai-sheng LIU Guo-shun YANG yong-feng YE Xie-feng SHI Zhou National Tobacco Cultivation and Physiological and Biochemical Center Henan Agricultural University Zhengzhou 450002 P.R. China Zhejiang Tongji Science and Technology Vocational College Hangzhou 311231 P.R.China Institute of Agricultural Remote Sensing and Information Technology College of Environment and Resource Science Zhejiang University Hangzhou 310029 P.R.China

The growth of tobacco is sensitive to environment conditions. The tobacco production is strictly restricted by regional cultivated land. Based on the principal of hiberarchy analysis and fuzzy mathematics and the technique of geographic information system （GIS）, the comprehensive evaluation of tobacco ecology suitability were studied according to the actual circumstances of the whole Henan tobacco planting regions, China. The evaluation index system of tobacco ecology suitability of Henan tobacco planting regions was established by choosing 17 evaluation indexes from 3 respects of climate, soil and landform with Delphi method. Furthermore, the membership function was set up according to the effects of each ecology factors on the growth and quality of tobacco suitability. And the analytical hierarchy process （AHP） was used to determine the weight of indexes by using quantitative analysis. Then the tobacco ecology suitability map of Henan tobacco plantation was drawn with GIS software mapGIS. It is found that the most areas of the western and southern parts of Henan Province, China, are the highly suitable regions, accounting for 22.52% of Henan tobacco planting areas. It is because that there are medium air temperature, sunshine and rainfall, medium soil pH value, and high contents of soil organic matter in the regions. Moreover, the topography is hill and massif, and the height above sea level is between 150-800 m there. Some areas of the southern and middle parts of Henan Province are the suitable ones, accounting for 34.99% of Henan tobacco planting areas. It is because that there are enough rainfall, medium air temperature, high contents of available N and available K in the soil in these regions. There are less suitable regions in the northern and eastern parts of the investigated regions because of drought, too high pH value and CI in the soil and irrigation water, accounting for 35.54% of the whole areas. It can be conducted rapidly and correctly by combining

关键词： GIS flue-cured tobacco evaluation factors AHP ecology suitability

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Microstructure and nanoindentation hardness of shot-peened ultrafine-grained low-alloy steel

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Journal of Iron and Steel Research International 2019年第5期26卷 472-482页

作者： Xiao-wei feng Juan Xie Wen-ying Xue yong-feng Shen Hong-bo Wang Zhen-yu Liu Institute of Systems Engineering of China Academy of Engineering Physics Mianyang 621999 Sichuan China Key Laboratory for Anisotropy and Texture of Materials (MOE) School of Materials Science and Engineering Northeastern University Shenyang 110819 Liaoning China The State Key Lab of Rolling and Automation Northeastern University Shenyang 110819 Liaoning China

The effect of shot peening (SP) on microstructure and hardness of ultrafine-grained (UFG) low-alloy steel was investigated. With increasing shot-peening time from 0.5 to 1.5 h, grain size of UFG low-alloy steel decreases from 400 to 280 nm at surface whilst that of the layer with a depth of 160μm decreases from (230 ± 15) to (75 ± 5) nm. Interestingly, nanoindentation shows that hardness increases linearly with increasing the SP duration, reaching a value as high as (7.10 ± 0.1) GPa at the depth of 160 μm after the SP duration of 1.5 h. The thickness of the SP treated layer is measured as^300 μm. The Hall-Petch (H-P) relationship was established for the hardening layer. Correspondingly, abrasion resistance should be ~51% higher than that of as-prepared UFG low-alloy steel. As shown in SP processing, grain refinement is the key factor responsible for the strengthening of the studied steel.

关键词： Low-alloy steel Shot peening Grain refinement Nanoindentation Hardness

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Giant Magnetic Tunneling Effect in 81NiFe/Al_(2)O_(3)/Fe Junction

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Chinese Physics Letters 1997年第3期14卷 213-216页

作者： CHEN Hui-yu feng yong-jia SU Chang Department of Physics University of Science and Technology of ChinaHefei 230026

A new effect,spin-polarized magnetovoltage(MV)effect,is observed in an 81NiFe/Al_(2)O_(3)/Fe junctions with cross-strip-electrode *** one ferromagnetic electrode carries current,a voltage can be found between the ends of the other ferromagnetic electrode,and it varies with the magnetization process of the two ferromagnetic *** MV ratio,which is much larger than the magnetoresistance ratio for the same junction,has reached 53% at room temperature.

关键词： ferromagnetic electrode Tunnel

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Electrocatalysis induced reconstruction of RuNiPO for highly efficient hydrogen evolution reaction

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Journal of Energy Chemistry 2023年第12期87卷 24-31,I0003页

作者： Junhui Hu Bai Xu Jiabin Xu Shuo Li Zhonghu Liu Cheng Lu yong feng Kun feng Jun Zhong Institute of Functional Nano and Soft Materials Laboratory(FUNSOM) Jiangsu Key Laboratory of Advanced Negative Carbon TechnologiesSoochow UniversitySuzhou 215123JiangsuChina Department of Chemistry University of Western OntarioLondonOntario N6A 5B7Canada

Reconstruction during the catalytic process has been considered to play a key role for the *** we report a RuNiPO based catalyst for efficient alkaline hydrogen evolution reaction(HER),which can benefit from a long-term reconstruction during HER for 10 h to continuously increase the *** final catalyst(e-RuNiPO)shows a huge morphology change from bulk sphere to highly exposed layered structure in the electrocatalysis process,and exhibits an interesting electronic structure modification with the electron transfer from Ru to Ni for better interfacial interaction and quick charge *** to the favorable morphology with more exposed active sites and the optimized electronic structure,the final catalyst can achieve an outstanding performance with only an overpotential of 15 mV at 10 mA cm^(-2)(with a good stability more than 100 h),even outperforming the performance of benchmark 20 wt%Pt/C catalyst(18 mV at 10 mA cm^(-2))by using a much lower Ru content.

关键词： Electrocatalyst Electrochemical reconstruction Hydrogen evolution reaction X-ray absorption spectroscopy

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Comprehensive impact of as-cast microstructure and ordered structures on formability of large-scale Fe-6.5 wt.%Si alloy ingots

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Journal of Iron and Steel Research International 2020年第2期27卷 180-187页

作者： Xiang-ju Shi yong-feng Liang Shi-bo Wen Zhi-yi Ding Bao Zhang Wei Song feng Ye State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

Large-scale Fe-6.5 wt.%Si ingot with excellent formability is required for a pilot line producing sheets through hot/cold *** variation of the as-cast microstructure,ordered structures and the formability of the Fe-6.5 wt.%Si alloy ingots with the cooling rate during casting was *** air-cooling condition,inhomogeneous microstructures with a low proportion of equiaxed grains were formed,but the formation of ordered structures was partially inhibited,especially *** microstructures with a high proportion of equiaxed grains were observed under the condition of furnace cooling,but the ordered structures were fully generated,and the degree of order is *** is generally believed that high degree of order is the main factor of brittleness,but the homogeneous microstructure(including grain morphology and size)of the furnace-cooled sample helps to improve the *** influence of these two aspects on formability is ***,the formability is tested through the flow stress during the compression and the microstructure after the *** results show that the furnace-cooled sample has better *** large-scale ingots,the control of as-cast microstructure becomes more significant than the control of degree of *** cooling during casting is important for the large-scale ingots to have good formability meeting the requirements of direct hot rolling.

关键词： Large-scale ingot Fe-6.5 wt.%Si alloy Cooling method Formability Ordered structure As-cast microstructure

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Numerical simulation on solidification behavior and structure of 38CrMoAl large round bloom using CAFE model

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Journal of Iron and Steel Research International 2023年第6期30卷 1222-1233页

作者： Rui-song Tan Wei Liu Bo Song Shu-feng Yang yong-feng Chen Xiao-tan Zuo Yan Huang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Wuhu Xinxing Ductile Pipe Co. Ltd.Wuhu 241002AnhuiChina

A coupled cellular automaton-finite element model was developed to simulate the solidification behavior and structure of 38CrMoAl large round bloom,in which mold electromagnetic stirring+final electromagnetic stirring was taken into consideration,under different superheat,casting speeds,and secondary cooling water *** trials for infrared temperature measurement and macro etch experiments of the post-test round bloom samples were used to verify the simulated solidification structure and temperature *** simulation results show that superheat and secondary cooling water flow have little influence on the surface temperature,center temperature,and center solid fraction while casting speed has a more obvious influence on solidification *** the increase in the casting speed of 0.02 m min^(-1),the solidification position is prolonged by about 1.64 *** the increasing specific water ratio by 0.02 L kg^(-1) each,the surface temperature of the secondary cooling zones decreases by about 18℃,and the solidification position shortens by about 0.11 *** the superheat increases from 10 to 40℃,the ratio of the equiaxed crystal zone decreases from 35.98% to 23.98%.The casting speed and secondary cooling water flow increase the equiaxed crystal ratios of the large round bloom,but neither is significant,both being about 2%.

关键词： 38CrMoAl large round bloom CAFE model Solidification structure Superheat Casting speed Secondary cooling water flow

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Strange Stars: Can Their Crust Reach the Neutron Drip Density?

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Chinese Journal of Astronomy and Astrophysics 2003年第6期3卷 535-542页

作者： Hai Fu and yong-feng HuangDepartment of Astronomy, Nanjing University, Nanjing 210093 Department of Astronomy Nanjing University Nanjing 210093 China

The electrostatic potential of electrons near the surface of static strange stars at zero temperature is studied within the frame of the MIT bag model. We find that for QCD parameters within rather wide ranges, if the nuclear crust on the strange star is at a density leading to neutron drip, then the electrostatic potential will be insufficient to establish an outwardly directed electric field, which is crucial for the survival of such a crust. If a minimum gap width of 200 fm is brought in as a more stringent constraint, then our calculations will completely rule out the possibility of such crusts. Therefore, our results argue against the existence of neutron-drip crusts in nature.

关键词： dense matter - elementary particles - stars: neutron

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Mean First-Passage Time of an Asymmetric Kinetic Model Driven by Two Different Kinds of Colored Noises

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Communications in Theoretical Physics 2008年第3期49卷 689-695页

作者： LI Dong-Xi XU Wei GUO yong-feng WANG Liang Department of Applied Mathematics Northwestern Polytechnical University Xi＇an 710072 China

The mean first-passage time （MFPT） of an asymmetric bistable system between multiplicative non-Gaussian noise and additive Gaussian white noise with nonzero cross-correlation time is investigated. Firstly, the non-Markov process is reduced to the Markov process through a path-integral approach; Secondly, the approximate Fokker Planck equation is obtained by applying the unified colored noise approximation and *** Theorem. The steady-state probability distribution （SPD） is also obtained. The basal functional analysis and simplification are employed to obtain the approximate expressions of MFPT T^±. The effects of the asymmetry parameter β, the non-Gaussian parameter （measures deviation from Gaussian character） r, the noise correlation times τ and τ2, the coupling coefficient A, the intensities D and a of noise on the MFPT are discussed. It is found that the asymmetry parameter β, the non-Gaussian parameter r and the coupling coefficient A can induce phase transition. Moreover, the main findings are that the effect of self-existent parameters （D, α, and τ） of noise and cross-correlation parameters （A, 7-2） between noises on MFPT T^± is different.

关键词： mean first-passage time asymmetric bistable system non-Gaussian noise Gaussian noise

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Effects of subgrain size and static recrystallization on the mechanical performance of polycrystalline material: A microstructure-based crystal plasticity finite element analysis

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Progress in Natural Science:Materials International 2015年第1期25卷 58-65页

作者： fengbo Han Bin Tang Hongchao Kou Jinshan Li yong feng State Key Laboratory of Solidification Processing Northwestern Polytechnical University Western Superconducting Technologies Co. Ltd.

In this paper, the effects of subgrain size and static recrystallization on the mechanical performance of polycrystalline material were investigated using a microstructure-based crystal plasticity finite element(CPFE) model. Firstly, polycrystalline microstructures with different mean subgrain sizes were prepared using simple assumption based on experimental observations, and intermediate microstructures during static recrystallization(SRX) were simulated by a cellular automata model adopting curvature driven grain/subgrain growth mechanism. Then, CPFE method was applied to perform stress analysis of plane strain tension on these virtual microstructures. The results show that the subgrains inside pre-existing grains have an effect on the heterogeneity of the stress distributions. The average stress decreases with increasing the mean subgrain radius. As grain/subgrain grows during SRX, the average stress also decreases. It can be deduced that well-defined and finer subgrain structure may strengthen the polycrystalline material, while grain/subgrain growth during SRX process will degrade the strength.

关键词： Static recrystallization Subgrain growth Cellular automata Crystal plasticity finite element Stress analysis

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CRYSTAL ORIENTATION AND MELTING BEHAVIOR OF POLY(ε-CAPROLACTONE) UNDER ONE-DIMENSIONALLY “HARD” CONFINED MICROENVIRONMENT

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Chinese Journal of Polymer Science 2013年第6期31卷 946-958页

作者： Xuan-bo Liu yong-feng Zhao Xing-he Fan 陈尔强 Beijing National Laboratory for Molecular Sciences Department of Polymer Science and Engineering and Key Laboratory of Polymer Chemistry and Physics of Ministry of Education College of Chemistry and Molecular Engineering Peking University Research Institute of Material Science Beijing Research Institute of Chemical Industry SINOPEC

Crystal orientation and melting behavior of poly（e-caprolactone） in a diblock copolymer of poly（e-caprolactone）- block-poly（2,5-bis[4-methoxyphenyl]oxycarbonyl）styrene）（PCL-b-PMPCS） was investigated. The degrees of polymerization of the PCL and PMPCS block are 200 and 98, respectively. With the PMPCS in a columnar liquid crystalline phase, the diblock is rod-coil one, which exhibits a lamellar phase morphology with the PCL layer thickness of 15.2 nm. Since the glass transition temperature of PMPCS block is much higher than the melting temperature of PCL, the crystallization of PCL is in a one-dimensionally ＂hard＂ confinement environment. Mainly on the basis of two-dimensional wide-angle X-ray diffraction experiments, we identified the orientation of PCL isothermally crystallized at various crystallization temperatures （Tos）. At high Tcs （To 〉 10 ℃）, the c-axis of the PCL crystal is along the layer normal of the microphase-separated sturcture. Decreasing Tc can result in the tilting of PCL c-axis with respect to the layer normal. The lower the Tc is, the more the c-axis inclines. Meanwhile, the b-axis of PCL remains perpendicular to the layer normal. At a very low Tc of-78 ℃, the orientation of the PCL crystals is completely random. For the samples isothermally crystallized at Tc 〈 10 ℃, double melting behavior can be observed. While the low temperature endotherm reflects the melting of the crystals originally formed at the Tc applied, the high temperature one is associated with the crystals subjected to the process of recrystallization/reorganization upon heating due to the annealing effect.

关键词： Crystallization Melting Confinement Diblock copolymer Rod-coil.

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