[Objective] This study aimed to investigate the effects of different concen- trations of antimony and modifier calcium magnesium phosphate on photosynthetic characteristics of edible amaranth, flowering Chinese cabbag...[Objective] This study aimed to investigate the effects of different concen- trations of antimony and modifier calcium magnesium phosphate on photosynthetic characteristics of edible amaranth, flowering Chinese cabbage, spinach and flowering Chinese cabbage. [Method] By outdoor potting simulation experiment, soil matrixes containing 10.00, 20.00, 50.00, 70.00 and 100.00 mg/kg antimony （Sb3＋） were pre- pared; soil without antimony was used as control （CK）. Each pot was loaded with 0.10 kg/kg vegetable special fertilizer, mixed evenly, and divided into two shares： one share was supplemented with 1.75 g/kg modifier calcium magnesium phosphate and mixed evenly; the other share contained no calcium magnesium phosphate. Af- ter the generation of three true leaves, seedlings with uniform growth were trans- planted into the prepared soil matrixes, eights seedlings per pot. Vegetable seedlings were watered regularly to maintain 70% of field capacity. After 45 d, veg- etable plants were harvested and washed clean with distilled water for measurement of indicators of photosynthetic characteristics. [Result] With the increase of antimony concentration, relative chlorophyll content （SPAD value） and net photosynthetic rate of four vegetable species increased first and then declined, while stomatal conduc- tance of vegetable leaves was linearly reduced. [Conclusion] Appropriately adding modifier calcium magnesium phosphate can effectively improve the photosynthetic characteristics of four vegetable species and reduce the toxic effects of heavy metal antimony on vegetables.展开更多
In this work,the reflux classifier with closely spaced inclined channels is used as the pre-concentration facility to improve the separation efficiency before the shaking table separation.Three operating parameters of...In this work,the reflux classifier with closely spaced inclined channels is used as the pre-concentration facility to improve the separation efficiency before the shaking table separation.Three operating parameters of reflux classifier(RC)to pre-concentrate fine(0.023−0.15 mm)tailings of antimony oxide were optimized by response surface methodology(RSM)using a three-level Box-Behnken design(BBD).The parameters studied for the optimization were feeding speed,underflow,and ascending water speed.Second-order response functions were produced for the Sb grade and recovery rate of the concentrate.Taking advantage of the quadratic programming,when the factors of feeding,underflow and ascending water are respectively 225,30 and 133 cm^3/min,a better result can be achieved for the concentrate grade of 2.31% and recovery rate of 83.17%.At the same time,70.48% of the tailings with the grade of 0.20% were discarded out of the feeding.The results indicated that the reflux classifier has a good performance in dealing with fine tailings of antimony oxide.Moreover,second-order polynomial equations,ANOVA,and three-dimensional surface plots were developed to evaluate the effects of each parameter on Sb grade and recovery rate of the concentrate.展开更多
基金Supported by Fund of Director of Hunan Institute of HorticultureProject for Cultivation Post in Citrus Industry System of Hunan Province(2013)~~
文摘[Objective] This study aimed to investigate the effects of different concen- trations of antimony and modifier calcium magnesium phosphate on photosynthetic characteristics of edible amaranth, flowering Chinese cabbage, spinach and flowering Chinese cabbage. [Method] By outdoor potting simulation experiment, soil matrixes containing 10.00, 20.00, 50.00, 70.00 and 100.00 mg/kg antimony （Sb3＋） were pre- pared; soil without antimony was used as control （CK）. Each pot was loaded with 0.10 kg/kg vegetable special fertilizer, mixed evenly, and divided into two shares： one share was supplemented with 1.75 g/kg modifier calcium magnesium phosphate and mixed evenly; the other share contained no calcium magnesium phosphate. Af- ter the generation of three true leaves, seedlings with uniform growth were trans- planted into the prepared soil matrixes, eights seedlings per pot. Vegetable seedlings were watered regularly to maintain 70% of field capacity. After 45 d, veg- etable plants were harvested and washed clean with distilled water for measurement of indicators of photosynthetic characteristics. [Result] With the increase of antimony concentration, relative chlorophyll content （SPAD value） and net photosynthetic rate of four vegetable species increased first and then declined, while stomatal conduc- tance of vegetable leaves was linearly reduced. [Conclusion] Appropriately adding modifier calcium magnesium phosphate can effectively improve the photosynthetic characteristics of four vegetable species and reduce the toxic effects of heavy metal antimony on vegetables.
基金Project(2015SK20792)supported by Key Province Key Technology Research and Development Program of the Ministry of Science and Technology of Hunan,ChinaProjects(2019zzts703,2020zzts740,2020zzts202)supported by the Fundamental Research Funds for the Central Universities of ChinaProject(2020P4FZG03A)supported by State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization,China。
文摘In this work,the reflux classifier with closely spaced inclined channels is used as the pre-concentration facility to improve the separation efficiency before the shaking table separation.Three operating parameters of reflux classifier(RC)to pre-concentrate fine(0.023−0.15 mm)tailings of antimony oxide were optimized by response surface methodology(RSM)using a three-level Box-Behnken design(BBD).The parameters studied for the optimization were feeding speed,underflow,and ascending water speed.Second-order response functions were produced for the Sb grade and recovery rate of the concentrate.Taking advantage of the quadratic programming,when the factors of feeding,underflow and ascending water are respectively 225,30 and 133 cm^3/min,a better result can be achieved for the concentrate grade of 2.31% and recovery rate of 83.17%.At the same time,70.48% of the tailings with the grade of 0.20% were discarded out of the feeding.The results indicated that the reflux classifier has a good performance in dealing with fine tailings of antimony oxide.Moreover,second-order polynomial equations,ANOVA,and three-dimensional surface plots were developed to evaluate the effects of each parameter on Sb grade and recovery rate of the concentrate.
