An experiment was conducted to examine the role of Mn in P fixation through comparing with Al and Fe. Hydroxides and oxides of Al, Fe and Mn were prepared in lab under opened and closed conditions to react with phosph...An experiment was conducted to examine the role of Mn in P fixation through comparing with Al and Fe. Hydroxides and oxides of Al, Fe and Mn were prepared in lab under opened and closed conditions to react with phosphate. The newly formed Mn hydroxide showed the strongest P-fixing abilityl even several times higher than Fe hydroxide, but became the lowest rapidly due to ageing when exposed to air. Mn oxide showed the lowest p-fixing ability. Therefore, a sound consideration on P fixation should be based on both quantities and p-fixing abilities of the compounds of Fe, Al and Mn. The importance of Mn on P availability should receive more attention especially under oxidation-reduction dynamic conditions.展开更多
Vesicular-arbuscular mycorrhizal (VAM) fungi have been credited with improving the groWth and mineral nutrition of many host plants but these effects are moderated by soil factors and nutrient balance. The combined ef...Vesicular-arbuscular mycorrhizal (VAM) fungi have been credited with improving the groWth and mineral nutrition of many host plants but these effects are moderated by soil factors and nutrient balance. The combined effects of VAM, Zn and P application on the growth and translocation of nutrients in wheat were investigated using a calcareous soil marginal in P and Zn concentrations. Wheat was grown in a growth chamber under various combinations of VAM, P and Zn with measurements done at heading stage and maturity.Vegetative dry matter accumulation was increased by P application and reduced by VAM treatments. Both P and VAM increased grain yield. Zinc concentration and uptake were generally reduced by P addition and VAM infection. There were no antagonistic effects of Zn on P acquisition in the plant. The role of VAM in enhancing the translocation of Zn and P from root to grain would be beneficial to seed setting and yield.展开更多
Soils were collected from 2-year (2-y) and 3-year(3-y) old red-pine seedling plots in two tree nurseries,Hayward in the north and Wilson in the southwestern part of Wisconsin State respectively,and equilibrated with 0...Soils were collected from 2-year (2-y) and 3-year(3-y) old red-pine seedling plots in two tree nurseries,Hayward in the north and Wilson in the southwestern part of Wisconsin State respectively,and equilibrated with 0.01 M Ca(NO3)2) for soil solution Zn and Mn (solu-Zn and Mn),and with 0.01 M Ca(NO3)2+0.005 M EDTA for soil absorbed Zn and Mn(ad-Zn and Mn).Buffering capacity of soil Zn and Mn (b-Zn and Mn) was obtained from the ratio of ad-Zn and Mn to the solu-Zn and Mn.The concerned traces in pine seedling needles(ndls),stems(sts) and roots (rts) were simultaneously measured.The results obtained show that: About 60% of solu-and ad- Zn ranged from 0.2 to 0.4 and from 1 to 2μg/ g soil respectively.About 70% of b-Zn was within 3-10.The highest content of solu-Zn compared with the lowest showed a discrepance of more than 10-fold.The two forms of soil Zn were commonly higher in Wilson than in Haywark Nursery. About 80% of solu-,ad- and b-Mn were within 3-10,5-5.8μg/ g soil and 1-2 respectively.Influence of low buffering capacity on solu-Zn and Mn was about 20 times stronger than that of the high.The E-value,a ratio of accumulated Zn and Mn in needles to those in the soil solution,is proved to be:E-Zn> E-Mn;E-sts> E-ndls or E-rts;and E-2y>E-3y.Curvilinear and/ or linear correlations between soil solu-,ad- and b-Zn and Mn and ndls-,sts-,rts-Zn and Mn were at very significant or significant levels.For predicting ndls-Zn and Mn,two realizable and simple models from two regression equations were established through the selection of related parameters and dependent variables.Binary regression analysis basically eliminated the influence of soil pH on the prediction of Zn and Mn in needles.Soil pH was thus thought to be excluded from the model.展开更多
REPUBLIC ACT NO. 7638 (RA 7638) - an act creating the Department of Energy, rationalizing the organization and functions of government agencies related to energy, and for other purposes. This act is also known as the...REPUBLIC ACT NO. 7638 (RA 7638) - an act creating the Department of Energy, rationalizing the organization and functions of government agencies related to energy, and for other purposes. This act is also known as the “department of energyact of 1992”.展开更多
Testing equality of covariance matrix has long been an interesting issue in statistics inference, To overcome the sparseness of data points in high-dimensional space and deal with the general cases, the author suggest...Testing equality of covariance matrix has long been an interesting issue in statistics inference, To overcome the sparseness of data points in high-dimensional space and deal with the general cases, the author suggests several projection pursuit type statistics. Some results on the limiting distidbutions of the statistics are obtained. Some properties of bootstrap approximation are investigated. Furthermore, for computational reasons an approximation for the statistics based on number-theoretic roethod is applied. Several simulation experiments are performed.展开更多
The characteristics of magnetorheological fin- ishing (MRF) technique such as the behavior of magnetic particles and the magnetic field distribution have been inves- tigated. Based on the established theoretical model...The characteristics of magnetorheological fin- ishing (MRF) technique such as the behavior of magnetic particles and the magnetic field distribution have been inves- tigated. Based on the established theoretical model, material removal function and removal rate experiments involving a K9 glass mirror are designed and carried out. Further experiments are carried out to improve the surface roughness of the workpiece. The final surface roughness with an initial value of 17.58 nm reached 0.4351 nm rms after 35 min of deterministic MRF, and the AFM measurements on microstructures of the polished surface are also improved by 0.445 nm rms without obvious defects.展开更多
文摘An experiment was conducted to examine the role of Mn in P fixation through comparing with Al and Fe. Hydroxides and oxides of Al, Fe and Mn were prepared in lab under opened and closed conditions to react with phosphate. The newly formed Mn hydroxide showed the strongest P-fixing abilityl even several times higher than Fe hydroxide, but became the lowest rapidly due to ageing when exposed to air. Mn oxide showed the lowest p-fixing ability. Therefore, a sound consideration on P fixation should be based on both quantities and p-fixing abilities of the compounds of Fe, Al and Mn. The importance of Mn on P availability should receive more attention especially under oxidation-reduction dynamic conditions.
文摘Vesicular-arbuscular mycorrhizal (VAM) fungi have been credited with improving the groWth and mineral nutrition of many host plants but these effects are moderated by soil factors and nutrient balance. The combined effects of VAM, Zn and P application on the growth and translocation of nutrients in wheat were investigated using a calcareous soil marginal in P and Zn concentrations. Wheat was grown in a growth chamber under various combinations of VAM, P and Zn with measurements done at heading stage and maturity.Vegetative dry matter accumulation was increased by P application and reduced by VAM treatments. Both P and VAM increased grain yield. Zinc concentration and uptake were generally reduced by P addition and VAM infection. There were no antagonistic effects of Zn on P acquisition in the plant. The role of VAM in enhancing the translocation of Zn and P from root to grain would be beneficial to seed setting and yield.
文摘Soils were collected from 2-year (2-y) and 3-year(3-y) old red-pine seedling plots in two tree nurseries,Hayward in the north and Wilson in the southwestern part of Wisconsin State respectively,and equilibrated with 0.01 M Ca(NO3)2) for soil solution Zn and Mn (solu-Zn and Mn),and with 0.01 M Ca(NO3)2+0.005 M EDTA for soil absorbed Zn and Mn(ad-Zn and Mn).Buffering capacity of soil Zn and Mn (b-Zn and Mn) was obtained from the ratio of ad-Zn and Mn to the solu-Zn and Mn.The concerned traces in pine seedling needles(ndls),stems(sts) and roots (rts) were simultaneously measured.The results obtained show that: About 60% of solu-and ad- Zn ranged from 0.2 to 0.4 and from 1 to 2μg/ g soil respectively.About 70% of b-Zn was within 3-10.The highest content of solu-Zn compared with the lowest showed a discrepance of more than 10-fold.The two forms of soil Zn were commonly higher in Wilson than in Haywark Nursery. About 80% of solu-,ad- and b-Mn were within 3-10,5-5.8μg/ g soil and 1-2 respectively.Influence of low buffering capacity on solu-Zn and Mn was about 20 times stronger than that of the high.The E-value,a ratio of accumulated Zn and Mn in needles to those in the soil solution,is proved to be:E-Zn> E-Mn;E-sts> E-ndls or E-rts;and E-2y>E-3y.Curvilinear and/ or linear correlations between soil solu-,ad- and b-Zn and Mn and ndls-,sts-,rts-Zn and Mn were at very significant or significant levels.For predicting ndls-Zn and Mn,two realizable and simple models from two regression equations were established through the selection of related parameters and dependent variables.Binary regression analysis basically eliminated the influence of soil pH on the prediction of Zn and Mn in needles.Soil pH was thus thought to be excluded from the model.
文摘REPUBLIC ACT NO. 7638 (RA 7638) - an act creating the Department of Energy, rationalizing the organization and functions of government agencies related to energy, and for other purposes. This act is also known as the “department of energyact of 1992”.
文摘Testing equality of covariance matrix has long been an interesting issue in statistics inference, To overcome the sparseness of data points in high-dimensional space and deal with the general cases, the author suggests several projection pursuit type statistics. Some results on the limiting distidbutions of the statistics are obtained. Some properties of bootstrap approximation are investigated. Furthermore, for computational reasons an approximation for the statistics based on number-theoretic roethod is applied. Several simulation experiments are performed.
基金This work was supported by the National Natural Science Foundation of China(Grant No.50175062).
文摘The characteristics of magnetorheological fin- ishing (MRF) technique such as the behavior of magnetic particles and the magnetic field distribution have been inves- tigated. Based on the established theoretical model, material removal function and removal rate experiments involving a K9 glass mirror are designed and carried out. Further experiments are carried out to improve the surface roughness of the workpiece. The final surface roughness with an initial value of 17.58 nm reached 0.4351 nm rms after 35 min of deterministic MRF, and the AFM measurements on microstructures of the polished surface are also improved by 0.445 nm rms without obvious defects.