GeO2 is commonly used as dopant to adjust the refractive index profile(RIP)and the acoustic velocity profile(AVP)in the fiber,thereby forming different Brillouin gain spectrum(BGS)characteristics such as Brillouin ...GeO2 is commonly used as dopant to adjust the refractive index profile(RIP)and the acoustic velocity profile(AVP)in the fiber,thereby forming different Brillouin gain spectrum(BGS)characteristics such as Brillouin gain,acoustic mode number and peak intensity difference.When an optical fiber is used in optical fiber sensing or communication system,its BGS characteristics may play an important role in determining the performance of the system.In this paper,finite element analysis(FEA)method is used to study the influence of refractive index distribution and its corresponding AVP on the BGS in step-index,graded-index,and complex-index optical fibers.A new method has also been proposed to efficiently discriminate acoustic mode solution and obtain the new and full images of total Brillouin gain and acoustic modes number of the fiber as a function of the refractive index distribution,considering the influence of changing the refractive index difference and the geometric size simultaneously.For each type of optical fiber,the recommended parameter range is provided for optical fiber sensing and optical fiber communication.Moreover,the suitable optical fiber with close peak intensity in its multi-peak BGS is explored and achieved,which can be used in Brillouin beat spectrum detection systems to improve sensing accuracy.展开更多
为探明栽前土壤青枯菌含量与烟草发病情况的关系及云南省植烟土壤青枯菌定量分布特征,本研究应用青枯菌复合种(Ralstonia solanacearum species complex,RSSC)的qPCR检测体系对栽前土壤中的青枯菌进行定量检测,在烟草旺长期至成熟期调...为探明栽前土壤青枯菌含量与烟草发病情况的关系及云南省植烟土壤青枯菌定量分布特征,本研究应用青枯菌复合种(Ralstonia solanacearum species complex,RSSC)的qPCR检测体系对栽前土壤中的青枯菌进行定量检测,在烟草旺长期至成熟期调查青枯病发生情况。结果表明:(1)引起烟草青枯病发生的土壤病原群体阈值为103~104基因组/g;(2)青枯菌群体数量随土层加深呈下降趋势,主要集中于40 cm以内的土层;(3)检测716份土样发现青枯菌含量在104~10~5基因组/g的样品占比最多(37.43%),其中保山市、昆明市和临沧市占比较高,分别为58.33%、51.43%、45.25%;大理州、昭通市、文山州、楚雄州及玉溪市含菌量<103基因组/g的样品占比最多,分别为62.50%、61.54%、56.04%、48.48%和41.67%;(4)夏季轮作禾本科作物的土壤青枯菌含量极显著低于连作烟田;与冬闲相比,前茬种植茄科、蓼科、十字花科作物的土壤青枯菌含量较高,而种植豆科和菊科作物则较低,但只有豆科作物显著降低了青枯菌含量。按照103~104基因组/g的风险阈值,云南省昆明市、临沧市、普洱市、曲靖市、红河州、保山市发生青枯病的风险较高,需注意防治。展开更多
According to the characteristics of FCC diesel, a technology of liquid-phase hydrodesulfurization of the diesel in tubular reactors was proposed and lab-scale experiments were carried out. A kinetic model for the hydr...According to the characteristics of FCC diesel, a technology of liquid-phase hydrodesulfurization of the diesel in tubular reactors was proposed and lab-scale experiments were carried out. A kinetic model for the hydrodesulfurization process was developed and verified. The model was utilized to predict the sulfur content of products under different operating conditions. The effects of temperature, space velocity, pressure, and hydrogen concentration on the dcsulfurization rate were investigated.展开更多
基金supported by the National Natural Science Foundation of China(Nos.61875086,61377086)Aerospace Science Foundation of China(No.2016ZD52042)Foundation of Graduate Innovation Center in Nanjing University of Aeronautics and Astronautics(No.kfjj20170801)。
摘要GeO2 is commonly used as dopant to adjust the refractive index profile(RIP)and the acoustic velocity profile(AVP)in the fiber,thereby forming different Brillouin gain spectrum(BGS)characteristics such as Brillouin gain,acoustic mode number and peak intensity difference.When an optical fiber is used in optical fiber sensing or communication system,its BGS characteristics may play an important role in determining the performance of the system.In this paper,finite element analysis(FEA)method is used to study the influence of refractive index distribution and its corresponding AVP on the BGS in step-index,graded-index,and complex-index optical fibers.A new method has also been proposed to efficiently discriminate acoustic mode solution and obtain the new and full images of total Brillouin gain and acoustic modes number of the fiber as a function of the refractive index distribution,considering the influence of changing the refractive index difference and the geometric size simultaneously.For each type of optical fiber,the recommended parameter range is provided for optical fiber sensing and optical fiber communication.Moreover,the suitable optical fiber with close peak intensity in its multi-peak BGS is explored and achieved,which can be used in Brillouin beat spectrum detection systems to improve sensing accuracy.
摘要为探明栽前土壤青枯菌含量与烟草发病情况的关系及云南省植烟土壤青枯菌定量分布特征,本研究应用青枯菌复合种(Ralstonia solanacearum species complex,RSSC)的qPCR检测体系对栽前土壤中的青枯菌进行定量检测,在烟草旺长期至成熟期调查青枯病发生情况。结果表明:(1)引起烟草青枯病发生的土壤病原群体阈值为103~104基因组/g;(2)青枯菌群体数量随土层加深呈下降趋势,主要集中于40 cm以内的土层;(3)检测716份土样发现青枯菌含量在104~10~5基因组/g的样品占比最多(37.43%),其中保山市、昆明市和临沧市占比较高,分别为58.33%、51.43%、45.25%;大理州、昭通市、文山州、楚雄州及玉溪市含菌量<103基因组/g的样品占比最多,分别为62.50%、61.54%、56.04%、48.48%和41.67%;(4)夏季轮作禾本科作物的土壤青枯菌含量极显著低于连作烟田;与冬闲相比,前茬种植茄科、蓼科、十字花科作物的土壤青枯菌含量较高,而种植豆科和菊科作物则较低,但只有豆科作物显著降低了青枯菌含量。按照103~104基因组/g的风险阈值,云南省昆明市、临沧市、普洱市、曲靖市、红河州、保山市发生青枯病的风险较高,需注意防治。
基金the financial support from the SINOPEC(No.2014310031600599)
摘要According to the characteristics of FCC diesel, a technology of liquid-phase hydrodesulfurization of the diesel in tubular reactors was proposed and lab-scale experiments were carried out. A kinetic model for the hydrodesulfurization process was developed and verified. The model was utilized to predict the sulfur content of products under different operating conditions. The effects of temperature, space velocity, pressure, and hydrogen concentration on the dcsulfurization rate were investigated.