The dynamics of red edge parameters at different growth stages of wheat canopy was studied. The red edge position moved to the longer wavelength from erecting stage to heading stage, and returned to the original wavel...The dynamics of red edge parameters at different growth stages of wheat canopy was studied. The red edge position moved to the longer wavelength from erecting stage to heading stage, and returned to the original wavelength direction from grain-filling stage to maturity stage. The leaf total nitrogen content (LTN) is positively related to red edge amplitude (d λ red) and NIR platform amplitude (d λNIRP) and the correlation coefficient improved as growth stage extended. The chlorophyll content (TChl) is negatively related to d λ red from erecting stage to the elongation stage, and positively related to d λ red from heading stage to milky maturity stage. TChl is also positively related to d λNIRP. The leaf area index (LAI) is positively related to d λ red and d λNIRP, and the correlation coefficient improved as growth stage extended. It was concluded that d λ red and d λNIRP can be used as the indicators of winter wheat growth state, and guide the fertilization and irrigation decision making. The λNIRF is suitable for derivation of LTN, the d λ red for TChl, and the d λ red or d λNIRP for LAI.展开更多
In order to screen out the small watermelon varieties with red flesh suitable for soilless cultivation and to meet people's requirements of high-quality watermelons,comparative tests were conducted on 6 small wate...In order to screen out the small watermelon varieties with red flesh suitable for soilless cultivation and to meet people's requirements of high-quality watermelons,comparative tests were conducted on 6 small watermelon varieties with red flesh under soilless culture conditions in 2018.Based on the data of field traits,yield traits,quality traits and commercial traits,the integrated results showed that ‘Chuanqi 2’ had good quality and high yield,and the overall performance was the best.展开更多
Over the past three decades,research of high-altitude atmospheric discharges has received a lot of attention.This paper presents the results of experimental modeling of red sprites during a discharge in low-pressure a...Over the past three decades,research of high-altitude atmospheric discharges has received a lot of attention.This paper presents the results of experimental modeling of red sprites during a discharge in low-pressure air.To initiate ionization waves in a quartz tube,an electrodeless pulse-periodic discharge fed by microsecond voltage pulses with an amplitude of a few kilovolts and a repetition rate of tens of kHz were formed.In this case ionization waves(streamers)have a length of tens of centimeters.The main plasma parameters were measured at various distances along the tube.The measurements confirm the fact that ionization waves propagate in opposite directions from the zone of the main electrodeless discharge,just as it happens during the formation of red sprites.展开更多
利用低光度相机首次观测到了2013年7月31日华北地区一次中尺度对流系统(MCS)上空产生的中高层Sprite放电现象。结合闪电定位、天气雷达等同步观测,对一次MCS诱发的Sprite的形态学特征及其对应的母体闪电和雷暴系统的雷达回波特征等进行...利用低光度相机首次观测到了2013年7月31日华北地区一次中尺度对流系统(MCS)上空产生的中高层Sprite放电现象。结合闪电定位、天气雷达等同步观测,对一次MCS诱发的Sprite的形态学特征及其对应的母体闪电和雷暴系统的雷达回波特征等进行了详细分析。研究除发现了2例圆柱型、3例胡萝卜型和1例舞蹈型Sprite外,还发现了2例发光主体发育不完全的Y字型Sprite。估算的Sprite的底部平均高度低于61.8±3.5 km,顶部平均高度为84.3±6.8 km。Sprite持续时间算术平均值为25.7±9.8 ms,几何平均值为24.4 ms。Sprite的母体闪电均为正地闪,峰值电流在+62.5^+106.2 k A之间,算术平均值为+77.1±22.2 k A,是本次MCS所有正地闪平均峰值电流的1.4倍。Sprite母体闪电的脉冲电荷矩变化(i CMC)在+475^+922 C km之间,几何平均值为+571.0 C km。Sprite母体闪电发生在MCS雷达回波25~35 d BZ的层状云降水区,弱回波(<30 d BZ)面积的突然增加对Sprite的产生有重要指示作用。Sprite易发生在MCS成熟—消散阶段正地闪比例(POP)显著增加的时段。在本次MCS消散阶段中,有两个时间段可能有利于产生Sprite。在Sprite集中发生时间段,北京闪电综合探测网(BLNET)探测到的正地闪比例为54.2%,正地闪连续电流比例70.24%,连续电流持续时间为58.17±50.31 ms,有利于Sprite的产生。展开更多
In this paper, we report the location results for the parent lightning strokes of more than 30 red sprites observed over an asymmetric mesoscale convective system(MCS) on 30 July 2015 in Shandong Province, China, with...In this paper, we report the location results for the parent lightning strokes of more than 30 red sprites observed over an asymmetric mesoscale convective system(MCS) on 30 July 2015 in Shandong Province, China, with a long-baseline lightning location network of very-low-frequency/low-frequency magnetic field sensors. The results show that almost all of these cloud-to-ground(CG) strokes are produced during the mature stage of the MCS, and are predominantly located in the trailing stratiform region, which is similar to analyses of sprite-productive MCSs in North America and Europe. Comparison between the location results for the sprite-producing CG strokes and those provided by the World Wide Lightning Location Network(WWLLN) indicates that the location accuracy of WWLLN for intense CG strokes in Shandong Province is typically within 10 km, which is consistent with the result based on analysis of 2838 sprite-producing CG strokes in the continental United States. Also, we analyze two cases where some minor lightning discharges in the parent flash of sprites can also be located, providing an approach to confine the thundercloud region tapped by the sprite-producing CG strokes.展开更多
为提高红枣的营养价值及深加工利用潜力,以‘和田大枣’、‘延川狗头枣’、‘交城骏枣’、‘赞皇大枣’及‘宁阳大枣’五个代表性红枣品种为研究材料,利用嗜酸乳杆菌、植物乳杆菌及发酵乳杆菌的混合菌株进行乳酸发酵,探究混合菌株发酵...为提高红枣的营养价值及深加工利用潜力,以‘和田大枣’、‘延川狗头枣’、‘交城骏枣’、‘赞皇大枣’及‘宁阳大枣’五个代表性红枣品种为研究材料,利用嗜酸乳杆菌、植物乳杆菌及发酵乳杆菌的混合菌株进行乳酸发酵,探究混合菌株发酵对不同品种红枣浊汁品质的影响。结果表明:五个品种红枣汁皆是混合菌株发酵的良好基质,发酵结束活菌数皆超过6 lg CFU/mL。混合菌株发酵促进了酚类物质的转化,提高了咖啡酸、原儿茶酸及芦丁含量,发酵结束后含量分别达到了0.67~1.13、8.05~10.77及2.17~3.12 mg/mL。发酵后红枣汁抗氧化能力明显提高,DPPH自由基清除能力提高了38.2%~45.2%;FRAP铁力还原力提高了20.3%~60.6%。‘和田大枣’及‘赞皇大枣’枣汁中含有更高的总酚、葡萄糖、果糖及苹果酸,促进了乳酸菌的生长,其发酵汁具有较高的活菌数,分别达到了11.2及10.4 lg CFU/mL。此外两者发酵汁还具有较高的抗氧化能力及感官品质。研究结果可为红枣优良品种的筛选及应用提供理论指导。展开更多
基金supported by the Hi-Tech Demonstration Project of China National Planning Commitee(A00300100584)National Major Basic Research Project(G2000077907).
文摘The dynamics of red edge parameters at different growth stages of wheat canopy was studied. The red edge position moved to the longer wavelength from erecting stage to heading stage, and returned to the original wavelength direction from grain-filling stage to maturity stage. The leaf total nitrogen content (LTN) is positively related to red edge amplitude (d λ red) and NIR platform amplitude (d λNIRP) and the correlation coefficient improved as growth stage extended. The chlorophyll content (TChl) is negatively related to d λ red from erecting stage to the elongation stage, and positively related to d λ red from heading stage to milky maturity stage. TChl is also positively related to d λNIRP. The leaf area index (LAI) is positively related to d λ red and d λNIRP, and the correlation coefficient improved as growth stage extended. It was concluded that d λ red and d λNIRP can be used as the indicators of winter wheat growth state, and guide the fertilization and irrigation decision making. The λNIRF is suitable for derivation of LTN, the d λ red for TChl, and the d λ red or d λNIRP for LAI.
基金Supported by the Science and Technology Project of Beijing Municipal Bureau of Agriculture in 2018
文摘In order to screen out the small watermelon varieties with red flesh suitable for soilless cultivation and to meet people's requirements of high-quality watermelons,comparative tests were conducted on 6 small watermelon varieties with red flesh under soilless culture conditions in 2018.Based on the data of field traits,yield traits,quality traits and commercial traits,the integrated results showed that ‘Chuanqi 2’ had good quality and high yield,and the overall performance was the best.
基金funded by the Ministry of Science and Higher Education of the Russian Federation within Agreement no.075-15-2021-1026 of November 15,2021.
文摘Over the past three decades,research of high-altitude atmospheric discharges has received a lot of attention.This paper presents the results of experimental modeling of red sprites during a discharge in low-pressure air.To initiate ionization waves in a quartz tube,an electrodeless pulse-periodic discharge fed by microsecond voltage pulses with an amplitude of a few kilovolts and a repetition rate of tens of kHz were formed.In this case ionization waves(streamers)have a length of tens of centimeters.The main plasma parameters were measured at various distances along the tube.The measurements confirm the fact that ionization waves propagate in opposite directions from the zone of the main electrodeless discharge,just as it happens during the formation of red sprites.
文摘利用低光度相机首次观测到了2013年7月31日华北地区一次中尺度对流系统(MCS)上空产生的中高层Sprite放电现象。结合闪电定位、天气雷达等同步观测,对一次MCS诱发的Sprite的形态学特征及其对应的母体闪电和雷暴系统的雷达回波特征等进行了详细分析。研究除发现了2例圆柱型、3例胡萝卜型和1例舞蹈型Sprite外,还发现了2例发光主体发育不完全的Y字型Sprite。估算的Sprite的底部平均高度低于61.8±3.5 km,顶部平均高度为84.3±6.8 km。Sprite持续时间算术平均值为25.7±9.8 ms,几何平均值为24.4 ms。Sprite的母体闪电均为正地闪,峰值电流在+62.5^+106.2 k A之间,算术平均值为+77.1±22.2 k A,是本次MCS所有正地闪平均峰值电流的1.4倍。Sprite母体闪电的脉冲电荷矩变化(i CMC)在+475^+922 C km之间,几何平均值为+571.0 C km。Sprite母体闪电发生在MCS雷达回波25~35 d BZ的层状云降水区,弱回波(<30 d BZ)面积的突然增加对Sprite的产生有重要指示作用。Sprite易发生在MCS成熟—消散阶段正地闪比例(POP)显著增加的时段。在本次MCS消散阶段中,有两个时间段可能有利于产生Sprite。在Sprite集中发生时间段,北京闪电综合探测网(BLNET)探测到的正地闪比例为54.2%,正地闪连续电流比例70.24%,连续电流持续时间为58.17±50.31 ms,有利于Sprite的产生。
基金supported by the National Key Basic Research and Development (973) Program of China (Grant No. 2014CB441405)the Open Research Program of the Key Laboratory of Meteorological Disaster (Nanjing University of Information Science and Technology) of the Ministry of Education (Grant No. KLME1414)+2 种基金the National Natural Science Foundation of China (Grant No. 41574179)the Natural Science Foundation of Excellent Youth Program of China (Grant No. 41622501)“The Hundred Talents Program” of the Chinese Academy of Sciences (Grant No. 2013068)
文摘In this paper, we report the location results for the parent lightning strokes of more than 30 red sprites observed over an asymmetric mesoscale convective system(MCS) on 30 July 2015 in Shandong Province, China, with a long-baseline lightning location network of very-low-frequency/low-frequency magnetic field sensors. The results show that almost all of these cloud-to-ground(CG) strokes are produced during the mature stage of the MCS, and are predominantly located in the trailing stratiform region, which is similar to analyses of sprite-productive MCSs in North America and Europe. Comparison between the location results for the sprite-producing CG strokes and those provided by the World Wide Lightning Location Network(WWLLN) indicates that the location accuracy of WWLLN for intense CG strokes in Shandong Province is typically within 10 km, which is consistent with the result based on analysis of 2838 sprite-producing CG strokes in the continental United States. Also, we analyze two cases where some minor lightning discharges in the parent flash of sprites can also be located, providing an approach to confine the thundercloud region tapped by the sprite-producing CG strokes.
文摘为提高红枣的营养价值及深加工利用潜力,以‘和田大枣’、‘延川狗头枣’、‘交城骏枣’、‘赞皇大枣’及‘宁阳大枣’五个代表性红枣品种为研究材料,利用嗜酸乳杆菌、植物乳杆菌及发酵乳杆菌的混合菌株进行乳酸发酵,探究混合菌株发酵对不同品种红枣浊汁品质的影响。结果表明:五个品种红枣汁皆是混合菌株发酵的良好基质,发酵结束活菌数皆超过6 lg CFU/mL。混合菌株发酵促进了酚类物质的转化,提高了咖啡酸、原儿茶酸及芦丁含量,发酵结束后含量分别达到了0.67~1.13、8.05~10.77及2.17~3.12 mg/mL。发酵后红枣汁抗氧化能力明显提高,DPPH自由基清除能力提高了38.2%~45.2%;FRAP铁力还原力提高了20.3%~60.6%。‘和田大枣’及‘赞皇大枣’枣汁中含有更高的总酚、葡萄糖、果糖及苹果酸,促进了乳酸菌的生长,其发酵汁具有较高的活菌数,分别达到了11.2及10.4 lg CFU/mL。此外两者发酵汁还具有较高的抗氧化能力及感官品质。研究结果可为红枣优良品种的筛选及应用提供理论指导。
