In this paper we address the dynamics of compensation cutting process from both Laplace s frequency domain and the time domain of the first time, using the two computer aided analyzing softwares: MATLAB and SIMULI...In this paper we address the dynamics of compensation cutting process from both Laplace s frequency domain and the time domain of the first time, using the two computer aided analyzing softwares: MATLAB and SIMULINK. Theoretical analysis and simulation experiments firstly show that not only the systematical stiffness of workpiece, spindle and tools, but also the regenerated coefficient affects the compensation displacement effect. The results show that the SREC is practicable in reality to decease the spindle induced errors in many engineering applications such as hard boring through simulation and the preliminary experiment results.展开更多
[Objective] This study aimed to investigate the effects of arbuscular mycor-rhizal fungi （AMF） on growth of upland rice under soil Pb contamination. [Method] Using potting method, the effects of Glomus mosseae on th...[Objective] This study aimed to investigate the effects of arbuscular mycor-rhizal fungi （AMF） on growth of upland rice under soil Pb contamination. [Method] Using potting method, the effects of Glomus mosseae on the growth of Oryzal sati-va L. under different soil Pb concentrations （0, 300, 600 mg/kg） were investigated. [Result] According to the results, the mycorrhizal colonization rate of upland rice in-oculated with Glomus mosseae was significantly reduced （P〈0.05） with the increase of Pb concentration in soil. Compared with non-inoculation treatment, inoculation of arbuscular mycorrhizal fungi significantly improved the biomass of upland rice and Pb concentration of upland rice roots with addition of 300 mg/kg Pb but significantly reduced Pb concentration of upland rice shoots, which was consistent with the re-duced R/S （P〈0.05）; with addition of 600 mg/kg Pb, inoculation of arbuscular mycor-rhizal fungi significantly improved the biomass of upland rice roots （P〈0.05） but sig-nificantly reduced Pb concentration of upland rice shoots and roots （P〈0.05）; there was no significant difference in R/S between inoculation treatment and non-inocula-tion treatment. [Conclusion] This study indicated that inoculating Glomus mosseae under certain Pb concentrations could to some extent al eviate the toxic effects of Pb on Oryzal sativa L.展开更多
This paper sets up a robotic manipulator model on slewing crane. The model can synthetically describe the dynamic behavior of the load of slewing crane in rotating, elevating and hoisting motions. The dynamic equation...This paper sets up a robotic manipulator model on slewing crane. The model can synthetically describe the dynamic behavior of the load of slewing crane in rotating, elevating and hoisting motions. The dynamic equations of the system are recursively derived by a Newton Euler method. The dynamic behavior of the load of slewing crane in rotating motion is simulated on a computer. The method of robotic dynamics to derive the dynamic equations of the swing of load is accurate and convenient and it has good regularity. The result of the study provides a base in theory on design of crane and an accurate mathematical model for controlling the swing of load.展开更多
[Objective] This study aimed to clarify the effects of Pb2＋ and Cr3＋ stress on the contents of chlorophyl in Bryum argenteum and Barbula indica. [Method] B. ar-genteum and B. indica were cultured in different concen...[Objective] This study aimed to clarify the effects of Pb2＋ and Cr3＋ stress on the contents of chlorophyl in Bryum argenteum and Barbula indica. [Method] B. ar-genteum and B. indica were cultured in different concentrations of lead nitrate solu-tion or chromium chloride solution, to investigate the changes in contents of photo-synthetic pigments under lead and chromium single stress. [Result] The results showed that the effects of 1, 10 and 200 mg/L Pb2＋ on B. indica were greater than those on B. argenteum; the effects of 1, 50, 100 and 200 mg/L Cr3＋ on B. argen-teum were greater than those on B. indica. Total chlorophyl content in B. argen-teum and B. indica under different concentrations of Pb2＋ and Cr3＋ was decreased compared with that in control. The tolerance of B. indica to Pb2＋ pol ution was lower than that of B. argenteum, while the tolerance of B. indica to Cr3＋ pol ution was greater than that of B. argenteum. [Conclusion] Based on the conventional require-ments for monitoring materials, B. indica can be used as an indicator species to monitor heavy metal pol ution in the atmosphere of Zhengzhou.展开更多
To understand the role of ectomycorrhizas in improving the tolerance of its host to excessive heavy metals in soil, this study was conducted to exam the patterns of four fractions (the exchangeable, the carbonate-boun...To understand the role of ectomycorrhizas in improving the tolerance of its host to excessive heavy metals in soil, this study was conducted to exam the patterns of four fractions (the exchangeable, the carbonate-bound, the Fe-Mn oxide- bound and the organically bound) of both Cu and Cd in the rhizosphere of Chinese pine (Pinus tabulaeformis) seedlings grown in excessive Cu and Cd environment. The results showed that the speciation of Cu and Cd in the rhizosphere was significantly influenced by inoculation of ectomycorrhizal fungus Boletus edulis. Compared to the rhizosphere, the content of exchangeable Cu slightly decreased in the mycorrhizosphere of the seedlings grown in 166 and 400 mg kg-1 Cu contaminated soil, whereas the exchangeable Cd in the mycorrhizosphere decreased remarkably to only 33% and to 60% that of the rhizosphere at 0.75 and 1.50 mg kg-1 Cd levels, respectively. These indicate the potential capacity of mycorrhizas to alleviate the damage of heavy metals to the host plants by reducing the bioavailability of heavy metals in soil. Distribution of the 4 tested fractions of Cu and Cd at different contamination levels showed that there was a strong tendency of changing from loosely associated fractions to strongly associated fractions in the mycorrhizosphere. The most stable Cd fraction, organically bound Cd, was significantly larger in the mycorrhizosphere than in the rhizosphere at different Cd contamination levels. This phenomenon was also observed for Cu but the difference was not statistically significant.展开更多
In order to get a better understanding of the vacuum consumable arc remelting(VAR) processes and thus to optimize them,a 3D finite element model was developed for the temperature fields and heat transfer of titanium a...In order to get a better understanding of the vacuum consumable arc remelting(VAR) processes and thus to optimize them,a 3D finite element model was developed for the temperature fields and heat transfer of titanium alloy ingots during VAR process.The results show that the temperature fields obtained by the simulation are well validated through the experiment results.The temperature distribution is different during the whole VAR process and the steady-state molten pool forms at 329 s for d100 mm × 180 mm ingots.At the initial stage of remelting,the heat dissipation of crucible bottom plays an important role in the whole heat dissipation system.At the middle of remelting,the crucible wall becomes a major heat dissipation way.The effect of cooling velocity on the solidification structure of ingots was investigated based on the temperature fields and the results can well explain the macrostructure of titanium alloy ingots.展开更多
Fruiting bodies(500 g per site) of Tricholoma matsutake and the surface layer of soils collected from 20 spatially distant areas with pristine backgrounds across China were analyzed for potassium,magnesium,calcium,zin...Fruiting bodies(500 g per site) of Tricholoma matsutake and the surface layer of soils collected from 20 spatially distant areas with pristine backgrounds across China were analyzed for potassium,magnesium,calcium,zinc,iron,copper,manganese and cadmium using inductively coupled plasma optical emission spectroscopy.In terms of the bioconcentration and bioexclusion concept,K,Mg,Zn,and Cu were highly bioconcentrated,and their bioconcentration factor values varied between 75-615,2-107,38-603 and 7-76,respectively,across the 20 sites.Fe,Mn and Cd were moderately bioconcentrated and their bioconcentration factors(BCFs) varied between 0.6-34.0,0.4-37.0 and 0.9-7.0 respectively.However,Ca was excluded(BCF<1).T.matsutake is a species that is harvested in the wild as a valuable food and can contain a wide spectrum of both essential and hazardous mineral compounds that accumulate at elevated concentrations even if grown in pristine areas.The estimated intake rate of Cd in the fruiting bodies indicates cause for concern associated with this metal resulting from the daily consumption of between 200 and 400 g of fruiting bodies on a frequent basis during the mushrooming season.展开更多
A micro controller unit (MCU) oriented image acquisition and automatic guidance system is proposed. Image rectification and guidance recognition are discussed. The relation between camera setting and sight view is ill...A micro controller unit (MCU) oriented image acquisition and automatic guidance system is proposed. Image rectification and guidance recognition are discussed. The relation between camera setting and sight view is illustrated for smart car. A novel edge detection and trend prediction method is proposed for MCU processing unit for automatic guidance. A hardware-based binary proposal is discussed for guidance information detection with raster data. Keystone distortion correcting algorithm is also designed for MCU application and the performance of track type recognition is improved. Together with rollover preventing calculation, the proposed design is successfully applied to a 1∶10 scale model car.展开更多
文摘In this paper we address the dynamics of compensation cutting process from both Laplace s frequency domain and the time domain of the first time, using the two computer aided analyzing softwares: MATLAB and SIMULINK. Theoretical analysis and simulation experiments firstly show that not only the systematical stiffness of workpiece, spindle and tools, but also the regenerated coefficient affects the compensation displacement effect. The results show that the SREC is practicable in reality to decease the spindle induced errors in many engineering applications such as hard boring through simulation and the preliminary experiment results.
基金Supported by National Natural Science Foundation of China(81072989,40901149)Project for Promotion and Development of Private Education-Teaching and Educational Reform-Beijing City University "Construction of New Discipline-Water Supply and Drainage Engineering"~~
文摘[Objective] This study aimed to investigate the effects of arbuscular mycor-rhizal fungi （AMF） on growth of upland rice under soil Pb contamination. [Method] Using potting method, the effects of Glomus mosseae on the growth of Oryzal sati-va L. under different soil Pb concentrations （0, 300, 600 mg/kg） were investigated. [Result] According to the results, the mycorrhizal colonization rate of upland rice in-oculated with Glomus mosseae was significantly reduced （P〈0.05） with the increase of Pb concentration in soil. Compared with non-inoculation treatment, inoculation of arbuscular mycorrhizal fungi significantly improved the biomass of upland rice and Pb concentration of upland rice roots with addition of 300 mg/kg Pb but significantly reduced Pb concentration of upland rice shoots, which was consistent with the re-duced R/S （P〈0.05）; with addition of 600 mg/kg Pb, inoculation of arbuscular mycor-rhizal fungi significantly improved the biomass of upland rice roots （P〈0.05） but sig-nificantly reduced Pb concentration of upland rice shoots and roots （P〈0.05）; there was no significant difference in R/S between inoculation treatment and non-inocula-tion treatment. [Conclusion] This study indicated that inoculating Glomus mosseae under certain Pb concentrations could to some extent al eviate the toxic effects of Pb on Oryzal sativa L.
文摘This paper sets up a robotic manipulator model on slewing crane. The model can synthetically describe the dynamic behavior of the load of slewing crane in rotating, elevating and hoisting motions. The dynamic equations of the system are recursively derived by a Newton Euler method. The dynamic behavior of the load of slewing crane in rotating motion is simulated on a computer. The method of robotic dynamics to derive the dynamic equations of the swing of load is accurate and convenient and it has good regularity. The result of the study provides a base in theory on design of crane and an accurate mathematical model for controlling the swing of load.
基金Supported by Science and Technology Supporting Project of Henan Province(132300410358)~~
文摘[Objective] This study aimed to clarify the effects of Pb2＋ and Cr3＋ stress on the contents of chlorophyl in Bryum argenteum and Barbula indica. [Method] B. ar-genteum and B. indica were cultured in different concentrations of lead nitrate solu-tion or chromium chloride solution, to investigate the changes in contents of photo-synthetic pigments under lead and chromium single stress. [Result] The results showed that the effects of 1, 10 and 200 mg/L Pb2＋ on B. indica were greater than those on B. argenteum; the effects of 1, 50, 100 and 200 mg/L Cr3＋ on B. argen-teum were greater than those on B. indica. Total chlorophyl content in B. argen-teum and B. indica under different concentrations of Pb2＋ and Cr3＋ was decreased compared with that in control. The tolerance of B. indica to Pb2＋ pol ution was lower than that of B. argenteum, while the tolerance of B. indica to Cr3＋ pol ution was greater than that of B. argenteum. [Conclusion] Based on the conventional require-ments for monitoring materials, B. indica can be used as an indicator species to monitor heavy metal pol ution in the atmosphere of Zhengzhou.
基金the National Natural Science Foundation of China (No.20777004).
文摘To understand the role of ectomycorrhizas in improving the tolerance of its host to excessive heavy metals in soil, this study was conducted to exam the patterns of four fractions (the exchangeable, the carbonate-bound, the Fe-Mn oxide- bound and the organically bound) of both Cu and Cd in the rhizosphere of Chinese pine (Pinus tabulaeformis) seedlings grown in excessive Cu and Cd environment. The results showed that the speciation of Cu and Cd in the rhizosphere was significantly influenced by inoculation of ectomycorrhizal fungus Boletus edulis. Compared to the rhizosphere, the content of exchangeable Cu slightly decreased in the mycorrhizosphere of the seedlings grown in 166 and 400 mg kg-1 Cu contaminated soil, whereas the exchangeable Cd in the mycorrhizosphere decreased remarkably to only 33% and to 60% that of the rhizosphere at 0.75 and 1.50 mg kg-1 Cd levels, respectively. These indicate the potential capacity of mycorrhizas to alleviate the damage of heavy metals to the host plants by reducing the bioavailability of heavy metals in soil. Distribution of the 4 tested fractions of Cu and Cd at different contamination levels showed that there was a strong tendency of changing from loosely associated fractions to strongly associated fractions in the mycorrhizosphere. The most stable Cd fraction, organically bound Cd, was significantly larger in the mycorrhizosphere than in the rhizosphere at different Cd contamination levels. This phenomenon was also observed for Cu but the difference was not statistically significant.
基金Project(2007CB613802) supported by the National Basic Research Program of China
文摘In order to get a better understanding of the vacuum consumable arc remelting(VAR) processes and thus to optimize them,a 3D finite element model was developed for the temperature fields and heat transfer of titanium alloy ingots during VAR process.The results show that the temperature fields obtained by the simulation are well validated through the experiment results.The temperature distribution is different during the whole VAR process and the steady-state molten pool forms at 329 s for d100 mm × 180 mm ingots.At the initial stage of remelting,the heat dissipation of crucible bottom plays an important role in the whole heat dissipation system.At the middle of remelting,the crucible wall becomes a major heat dissipation way.The effect of cooling velocity on the solidification structure of ingots was investigated based on the temperature fields and the results can well explain the macrostructure of titanium alloy ingots.
基金funded by the National Science&Technology Pillar Program of Sichuan(2013NZ0029,2015NZ0092&2014FZ0004)the Youth Foundation Program of the Financial&Innovational Capacity Building Project of Sichuan(2014CXSF-030)
文摘Fruiting bodies(500 g per site) of Tricholoma matsutake and the surface layer of soils collected from 20 spatially distant areas with pristine backgrounds across China were analyzed for potassium,magnesium,calcium,zinc,iron,copper,manganese and cadmium using inductively coupled plasma optical emission spectroscopy.In terms of the bioconcentration and bioexclusion concept,K,Mg,Zn,and Cu were highly bioconcentrated,and their bioconcentration factor values varied between 75-615,2-107,38-603 and 7-76,respectively,across the 20 sites.Fe,Mn and Cd were moderately bioconcentrated and their bioconcentration factors(BCFs) varied between 0.6-34.0,0.4-37.0 and 0.9-7.0 respectively.However,Ca was excluded(BCF<1).T.matsutake is a species that is harvested in the wild as a valuable food and can contain a wide spectrum of both essential and hazardous mineral compounds that accumulate at elevated concentrations even if grown in pristine areas.The estimated intake rate of Cd in the fruiting bodies indicates cause for concern associated with this metal resulting from the daily consumption of between 200 and 400 g of fruiting bodies on a frequent basis during the mushrooming season.
文摘A micro controller unit (MCU) oriented image acquisition and automatic guidance system is proposed. Image rectification and guidance recognition are discussed. The relation between camera setting and sight view is illustrated for smart car. A novel edge detection and trend prediction method is proposed for MCU processing unit for automatic guidance. A hardware-based binary proposal is discussed for guidance information detection with raster data. Keystone distortion correcting algorithm is also designed for MCU application and the performance of track type recognition is improved. Together with rollover preventing calculation, the proposed design is successfully applied to a 1∶10 scale model car.
