膜下滴灌技术被广泛应用于内蒙古冷凉干旱地区的甜菜生产中。为探明施钾量对膜下滴灌甜菜光合生理特性和产质量的影响及其适宜钾肥用量,于2014—2015年在内蒙古凉城县设K_2O 0、90、180、270和360 kg hm^(–2) 5个施肥处理进行了研究。...膜下滴灌技术被广泛应用于内蒙古冷凉干旱地区的甜菜生产中。为探明施钾量对膜下滴灌甜菜光合生理特性和产质量的影响及其适宜钾肥用量,于2014—2015年在内蒙古凉城县设K_2O 0、90、180、270和360 kg hm^(–2) 5个施肥处理进行了研究。结果表明,钾素能够提高甜菜的光合性能,如促进株高、叶面积指数、净光合速率的增加;施钾肥180、270和360kghm^(–2)显著提高了叶丛快速生长期甜菜的净光合速率,影响净光合速率的最主要因素是RuBPCase活性,其次是气孔导度,净光合速率与甜菜产量呈极显著正相关。适宜的钾肥用量有利于块根、叶柄和叶片干重的增加及产量增加,但施钾过量,块根干物质分配比例下降,含糖率下降,块根干物质分配比例与甜菜含糖率呈显著正相关。施钾量270 kg hm^(–2)时产量最高, 90 kg hm^(–2)时含糖率最高,当施钾量大于180 kg hm^(–2)时,块根中K^+、Na^+含量增加,大于270 kg hm^(–2)时,块根中α-氨基酸含量增加,施钾量180 kg hm^(–2)时产糖量最高。综合考虑施钾量对膜下滴灌甜菜产量和品质的影响,内蒙古甜菜种植优势区域的钾肥推荐施用量为180 kg hm^(–2)。展开更多
The hardening mechanism of nanocry st alline Sm_(2)Fe_(15-x)M_(x)Ga_(2)C,as well as the effect of small amounts of Cu and Nb additions on the hardening behavior were reported.It is shown that the hardening mechanism i...The hardening mechanism of nanocry st alline Sm_(2)Fe_(15-x)M_(x)Ga_(2)C,as well as the effect of small amounts of Cu and Nb additions on the hardening behavior were reported.It is shown that the hardening mechanism is mainly of the pinning-type in Sm_(2)Fe_(15-x)M_(x)Ga_(2)C ribbons.Ret ention of pinning-type behavior,with a marginal increase in coercivity was observed for a small addition of Cu.The hardening mechanism is mainly of nucleation-type in Sm_(2)Fe_(15-x)M_(x)Ga_(2)C with a slightly decrease in coercivity.展开更多
Effects of substituting small amounts of Si for Co on the structure and magnetic properties of Gd_(2)Co_(17) compounds were studied by means of x-ray diffraction and magnetization measurements.All samples are of singl...Effects of substituting small amounts of Si for Co on the structure and magnetic properties of Gd_(2)Co_(17) compounds were studied by means of x-ray diffraction and magnetization measurements.All samples are of single phase with the rhombohedra1 Th_(2)Zn_(17),type structure.The substitution of Si for Co leads to an approximately linear decrease in the unit cell volume.The saturation moment at 1.5 K decreases linearly with increasing Si concentration,being an approximately linear rate of about 4.1μB per substituted Si.The Curie temperature of Gd_(2)Co_(17-x)Si_(x) is found to decrease monotonously from 1213 to 651 K,as x increases from 0 to 3.X-ray diffraction measurements on magnetically aligned powders show that the easy magnetization direction of Gd_(2)Co_(17-x)Si_(x) compounds changes from basal plane to c-axis with increasing Si concentcation.The samples with x=2,3 exhibit a room temperature uniaxial anisotropy.展开更多
文摘膜下滴灌技术被广泛应用于内蒙古冷凉干旱地区的甜菜生产中。为探明施钾量对膜下滴灌甜菜光合生理特性和产质量的影响及其适宜钾肥用量,于2014—2015年在内蒙古凉城县设K_2O 0、90、180、270和360 kg hm^(–2) 5个施肥处理进行了研究。结果表明,钾素能够提高甜菜的光合性能,如促进株高、叶面积指数、净光合速率的增加;施钾肥180、270和360kghm^(–2)显著提高了叶丛快速生长期甜菜的净光合速率,影响净光合速率的最主要因素是RuBPCase活性,其次是气孔导度,净光合速率与甜菜产量呈极显著正相关。适宜的钾肥用量有利于块根、叶柄和叶片干重的增加及产量增加,但施钾过量,块根干物质分配比例下降,含糖率下降,块根干物质分配比例与甜菜含糖率呈显著正相关。施钾量270 kg hm^(–2)时产量最高, 90 kg hm^(–2)时含糖率最高,当施钾量大于180 kg hm^(–2)时,块根中K^+、Na^+含量增加,大于270 kg hm^(–2)时,块根中α-氨基酸含量增加,施钾量180 kg hm^(–2)时产糖量最高。综合考虑施钾量对膜下滴灌甜菜产量和品质的影响,内蒙古甜菜种植优势区域的钾肥推荐施用量为180 kg hm^(–2)。
基金Supported by the National Natural Science Foundation of China under Grant Nos.59525101 and 59771024.
文摘The hardening mechanism of nanocry st alline Sm_(2)Fe_(15-x)M_(x)Ga_(2)C,as well as the effect of small amounts of Cu and Nb additions on the hardening behavior were reported.It is shown that the hardening mechanism is mainly of the pinning-type in Sm_(2)Fe_(15-x)M_(x)Ga_(2)C ribbons.Ret ention of pinning-type behavior,with a marginal increase in coercivity was observed for a small addition of Cu.The hardening mechanism is mainly of nucleation-type in Sm_(2)Fe_(15-x)M_(x)Ga_(2)C with a slightly decrease in coercivity.
基金Supported by the National Natural Science Foundation of China under Grant No.59525101。
文摘Effects of substituting small amounts of Si for Co on the structure and magnetic properties of Gd_(2)Co_(17) compounds were studied by means of x-ray diffraction and magnetization measurements.All samples are of single phase with the rhombohedra1 Th_(2)Zn_(17),type structure.The substitution of Si for Co leads to an approximately linear decrease in the unit cell volume.The saturation moment at 1.5 K decreases linearly with increasing Si concentration,being an approximately linear rate of about 4.1μB per substituted Si.The Curie temperature of Gd_(2)Co_(17-x)Si_(x) is found to decrease monotonously from 1213 to 651 K,as x increases from 0 to 3.X-ray diffraction measurements on magnetically aligned powders show that the easy magnetization direction of Gd_(2)Co_(17-x)Si_(x) compounds changes from basal plane to c-axis with increasing Si concentcation.The samples with x=2,3 exhibit a room temperature uniaxial anisotropy.
