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Goosegrass (Eleusine indica) density effects on cotton (Gossypium hirsutum)

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Journal of Integrative Agriculture 2015年第9期14卷 1778-1785页

作者： ma Xiao-yan WU Han-wen JIANG Wei-li ma Ya-jie ma yan State Key Laboratory of Cotton Biology Institute of Cotton ResearchChinese Academy of Agricultural Sciences Wagga Wagga Agricultural Institute NSW Department of Primary Industries

Goosegrass is one of the worst agricultural weeds on a worldwide basis. Understanding of its interference impact in crop ifeld wil provide useful information for weed control programs. Field experiments were conducted during 2010–2012 to determine the inlfuence of goosegrass density on cotton growth at the weed densities of 0, 0.125, 0.25, 0.5, 1, 2, and 4 plants m–1 of row. Seed cotton yield tended to decrease with the increase in weed density, and goosegrass at a density of 4 plants m–1 of row signiifcantly reduced cotton yields by 20 to 27%. A density of 11.6–19.2 goosegrass plant m–1 of row would result in a 50%cotton yield loss from the maximum yield according to the hyperbolic decay regression model. Bol production was not affected in the early growing season. But bol numbers per plant were reduced about 25%at the den-sity of 4 plants m–1 of row in the late growing season. Both cotton bol weight and seed numbers per bol were signiifcantly reduced (8%) at 4 goosegrass plants m–1 of row. Cotton plant height, stem diameter and sympodial branch number were not affected as much as cotton yields by goosegrass competition. Seed index, lint percentage and lint ifber properties were unaffected by weed competition. Intraspeciifc competition resulted in density-dependent effects on weed biomass per plant, 142–387 g dry weight by harvest. Goosegrass biomass m–2 tended to increase with increasing weed density as indicated by a quadratic response. The adverse impact of goosegrass on cotton yield identiifed in this study has indicated the need of effective goosegrass management.

关键词： competition goosegrass cotton yield fiber properties weed biomass

The Applied Research of Fracture in Three-point Bending to Blanking of Bearing Steel

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上海交通大学学报 2004年第Z2期38卷 199-205页

作者： Youtang Li Ping ma Changfeng yan College of Mechano-Electronic Engineering Lanzhou University of Technology Lanzhou730050 China College of Mechano-Electronic Engineering Lanzhou University of Technology Lanzhou730050 China College of Mechano-Electronic Engineering Lanzhou University of Technology Lanzhou730050 China

The application of fracture in three-point bending to blanking of bearing steel is studied in this paper. Several mechanical models of stress blanking are discussed at first. And then the experiments have been made in special equipment of three-point bending designed by us. Several problems, such as the suitable span, the relations between bending and tension bending complex, the ratio of blanking length to the diameter, the relations of blank length to force, the feature of fracture, are studied through the experiments. The suitable parameters of three-point bending to blanking, depth and tip radius of notch and the ratio between blanking length and stick diameter have been proposed.

关键词： bearing steel three points bending blanking crack technique fracture design

Influences of a Kind of Groove-blade on the Flow Field in a Compressor Cascade

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Journal of Thermal Science 2006年第3期15卷 193-199页

作者： Hongwei ma Wuying yan Qiao TIAN School of Jet Propulsion Beijing University of Aeronautics and Astronautics Beijing 100083 ChinaNational Key Laboratory on Aero-Engines Beijing 100083 China

This paper presents an experimental investigation of effects of a kind of streamwise-grooved blades on the flowfield in a compressor *** flow field downstream the cascade and the boundary layer on the suctionsurface were measured using a mini 5-hole pressure probe at different incidence *** flow field in thegroove cascade was compared with that in the smooth *** measurement results indicate that:(1)thegroove surface can restrain the development of the boundary layer on the suction surface;(2)the grooves canrestrain the radial migration of the low-energy fluids in the boundary layer on the suction surface;(3)the grooveblades can reduce total pressure loss and flow blockage in the cascade at the incidence angles of 0°,5°and 8°;(4)the maximum benefit of 8.6% loss reduction was obtained at the incidence angle of 5° while negative benefit of-3.0% loss reduction occurred at the incidence angle of-5°.

关键词： groove blade compressor cascade secondary flow flow loss boundary layer

Mn-CeOx/Ti-PILCs for selective catalytic reduction of NO with NH_3 at low temperature

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Journal of Environmental Sciences 2012年第3期24卷 499-506页

作者： Boxiong Shen Hongqing ma yan Yao College of Environmental Science and Engineering Nankai University94 Weijin Roadlianjin 300071China

Titanium-pillared clays （Ti-PILCs） were obtained by different ways from TiCl4, Ti（OC3H7）4 and TiOSO4, respectively. Mn-CeOx/Ti- PILCs were then prepared and their activities of selective catalytic reduction （SCR） of NO with NH3 at low-temperature were evaluated. Mn-CeOx/Ti-PILCs were characterized by X-ray diffraction, N2 adsorption, Fourier transform infrared spectroscopy, thermal analysis, temperature-programmed desorption of ammonia and H2-temperature-programmed reduction. It was found that Ti-pillar tend to be helpful for the enlargement of surface area, pore volume, acidity and the enhancement of thermal stability for Mn-CeOx/Ti-PILCs. Mn- CeOx/Ti-PILCs catalysts were active for the SCR of NO. Among three resultant Mn-CeOx/Ti-PILCs, the catalyst from TiOSO4 showed the highest activity with 98% NO conversion at 220°C, it also exhibited good resistance to H2O and SO2 in flue gas. The catalyst from TiCl4 exhibited the lowest activity due to the unsuccessful pillaring process.

关键词： Mn-CeOx/Ti-PILCs titania-pillared methods low-temperature SCR

Towards direct superlubricity and superlow wear via amino modification of polyhydroxy alcohol solutions

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Friction 2024年第9期12卷 1980-1990页

作者： Qiang ma Chengpeng yan Rui yan Xin XU Haifeng WANG State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi'an 710072China Chongqing Innovation Center Northwestern Polytechnical UniversityChongqing 401135China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518063China

Friction remains as the primary mode of energy dissipation and components wear,and achieving superlubricity shows high promise in energy conservation and lifetime wear *** results in this work demonstrate that direct superlubricity combined with superlow wear can be realized for steel/Si_(3)N_(4)contacts on engineering scale when polyhydroxy alcohol solution was selectively modified by amino *** direct superlubricity occurs because 3-amino-1,2-propanediol molecules at the friction interface could be induced to rotate and adsorb vertically on the friction surface,forming in-situ thick and dense molecular films to passivate the asperity ***,amino modification is also conducive to improving the lubrication state from boundary to mixed lubrication regime by strengthening the intermolecular hydrogen bonding interaction,presenting enhanced load-bearing capability and reduced direct solid asperity ***,direct superlow average friction of 0.01 combined with superlow wear are achieved *** design principle of direct superlubricity and superlow wear in this work indeed offers an effective strategy to fundamentally improve energy efficiency and provide lifetime wear protection for moving mechanical assemblies.

关键词： direct superlubricity amino modification molecular layer superlow wear

Collision-induced Rotational Energy Transfer in an Atom-Diatom System

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Chinese Journal of Chemical Physics 2008年第5期21卷 457-462页

作者： yan-qing Ni Jian Li Feng-cai ma Department of Physics Liaoning University Shenyang 110036 China Department of Science Shenyang Institute of Aeronautical Engineering Shengyang 110036 China

As a further theoretical study of the collision-induced quantum interference on rotational energy transfer in an atom-diatom system, based on the first-Born approximation of time-dependent perturbation theory, taking into account the anisotropic Lennard-Jones interaction potential and the long-range interaction potential, the differential interference angles in singlet-triplet mixed states of CO A^1Π（v=9）-e3∑-（v=1） system in collision with He, Ne, Ar, and other partners were calculated theoretically. The relationships of differential interference angle versus impact parameters, including collision parameter b and velocity, are obtained.

关键词： Rotational energy transfer Collision-induced quantum interference Interference angle

Certrust:An SDN-Based Framework for the Trust of Certificates against Crossfire Attacks in IoT Scenarios

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Computer Modeling in Engineering & Sciences 2023年第3期134卷 2137-2162页

作者： Lei yan maode ma Dandan Li Xiaohong Huang yan ma Kun Xie School of Computer Science(National Pilot Software Engineering School) Beijing University of Posts and TelecommunicationsBeijingChina College of Engineering QatarUniversityDohaQatar

The low-intensity attack flows used by Crossfire attacks are hard to distinguish from legitimate *** methods to identify the malicious flows in Crossfire attacks are rerouting,which is based on *** these existing mechanisms,the identification of malicious flows depends on the IP ***,the IP address is easy to be changed by *** the IP address,the certificate ismore challenging to be tampered with or ***,the traffic trend in the network is towards *** certificates are popularly utilized by IoT devices for authentication in encryption *** proposed a new way to verify certificates for resource-constrained IoT devices by using the SDN *** on DTLShps,the SDN controller can collect statistics on *** this paper,we proposeCertrust,a framework based on the trust of certificates,tomitigate the Crossfire attack by using SDN for *** goal is ***,the trust model is built based on the Bayesian trust system with the statistics on the participation of certificates in each Crossfire ***,the forgetting curve is utilized instead of the traditional decay method in the Bayesian trust system for achieving a moderate decay ***,for detecting the Crossfire attack accurately,a method based on graph connectivity is ***,several trust-based routing principles are proposed tomitigate the Crossfire *** principles can also encourage users to use certificates in *** performance evaluation shows that Certrust is more effective in mitigating the Crossfire attack than the traditional rerouting ***,our trust model has a more appropriate decay rate than the traditional methods.

关键词： Trust model certificate SDN Crossfire attack bayesian trust system forgetting curve IoT

Influence of Aspect Ratio on Giant magnetoimpedance Effect for Fe_(67)Co_(18)Si_(11)B_4 Amorphous Ribbons

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Acta Metallurgica Sinica(English Letters) 2017年第12期30卷 1236-1242页

作者： yan-Hong Ding Ke Xue Wei-yan Wang Xu ma School of Electrical and Electronic Engineering Tianjin Key Laboratory of Film Electronic and Communication Devices Tianjin University of Technology Tianjin 300384 China School of material Science and Engineering Tianjin University of Technology Tianjin 300384 China Tianjin Engineering Center of Near-Net-Shape Forming Technology for Metallic materials Tianjin 300402 China

The effect of sample geometry aspect ratio （l/w） on the giant magnetoimpedance （GMI） in Fe67Co18Si11B4 amorphous ribbons was investigated systematically. The GMI profiles were measured as a function of the external magnetic field at different frequencies up to 110 MHz. The results show that there exists a critical aspect ratio （（l/w）0 = 5.4） below which the maximum GMI effect and sensitivity η decrease with decreasing l/w and above which the maximum GMI effect keeps almost constant and η decreases with increasing l/w. The observed dependence on aspect ratio as （l/w）〈（l/w）0 is correlated with the magnetization process： Complex domain structures emerged near the ribbon ends to decrease the magnetostatic energy, modify the transverse permeability and consequently GMI response. Contributions from transverse permeability and resistance may dominantly determine the change of GMI effect as （l/w）〉（l/w）0.

关键词： Amorphous magnetic property magnetoimpedance

Deposition of Ti-Si-N coatings in deep blind-hole with pulsed dc power

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中国有色金属学会会刊：英文版 2004年第Z1期14卷 260-263页

作者： ma Da-yan ma Sheng-li XU Ke-wei State Key Laboratory for Mechanical Behavior of materials Xi''an Jiaotong University Xi''an 710049 China State Key Laboratory for Mechanical Behavior of MaterialsXi''an Jiaotong University Xi''an 710049 China State Key Laboratory for Mechanical Behavior of MaterialsXi''an Jiaotong University Xi''an 710049 China

Multiphase nanocomposite Ti-Si-N coatings deposited by pulsed dc plasma enhanced chemical vapor deposition technique on the surface of HSS substrate, which were bolted with deep blind-hole to simulate the complexshaped surface of various tools, were investigated. The micrographs show that the surface morphologies of the coatings become coarser with an increasing depth of the bottom holes. And the silicon content increases in Ti-Si-N coatings, which are composed of nanocrystalline TiN, nano-sized amorphous Si3N4, and occasionally amorphous or nanocrysralline TiSi2. The thickness of the coatings decreases with the increasing depth of holes, which may result from the changes of the composition in the coatings. The microhardness of the coatings increases firstly with the increasing depth of holes, reaches a maximum value of about HV5 700 at 10mm depth, and then decreases at larger depth.

关键词： nanocomposite pulsed dc PCVD Ti-Si-N deep blind-hole