采用诱集法和单孢接种培养技术,自湖北省不同棉区的棉花根际土壤中分离到能在棉花上形成VA菌根的真菌孢子和孢子果,依其显微形态特征对大部分菌株进行了种的鉴定。在已鉴定到种的6个菌株中,除Glomus mosseae(Nicol.and Gerd.)Gerd.and T...采用诱集法和单孢接种培养技术,自湖北省不同棉区的棉花根际土壤中分离到能在棉花上形成VA菌根的真菌孢子和孢子果,依其显微形态特征对大部分菌株进行了种的鉴定。在已鉴定到种的6个菌株中,除Glomus mosseae(Nicol.and Gerd.)Gerd.and Trappe和G.intraradices Schenck and Smith外,G.hoi Berch and Trappe.G.albidum Walker and Rhodes,G.ambisporum ⅡSmith and Schenck和G.geosporum(Nicol.and Gerd.)Walker4个种均为我国的新记录,其中G.albidam由于与Walker的描述不尽一致故命名为潜江变种(var.Qianjiang)。展开更多
为研究高压直流(HVDC)输电系统中油纸绝缘的老化状态与空间电荷效应对其击穿特性的影响,采用加速热老化处理得到3种不同老化程度的油纸绝缘试样,通过同极性不同幅值的预压方式注入空间电荷,测量其击穿电压;采用电声脉冲法(PEA)在室温下...为研究高压直流(HVDC)输电系统中油纸绝缘的老化状态与空间电荷效应对其击穿特性的影响,采用加速热老化处理得到3种不同老化程度的油纸绝缘试样,通过同极性不同幅值的预压方式注入空间电荷,测量其击穿电压;采用电声脉冲法(PEA)在室温下观察试品的空间电荷分布,进一步分析了油纸内部的电场分布情况和陷阱分布特性。实验结果表明:经3 k V同极性预压后试品的击穿电压整体高于未经预压处理的试品;且随着油纸绝缘老化程度的加剧,介质内部浅陷阱密度增大;随着电荷注入量的逐渐增加、电荷效应的增强,击穿电压有所提高。但经4 k V同极性预压后试品的击穿电压整体低于经3 k V同极性预压后试品的击穿电压;因此,在实际运行中,同极性预压幅值超过一定阈值时反而会出现击穿电压降低的现象,应引起特别注意。展开更多
Cold trapped ions can be excellent sensors for ultra-precision detection of physical quantities,which strongly depends on the measurement situation at hand.The stylus ion trap,formed by two concentric cylinders over a...Cold trapped ions can be excellent sensors for ultra-precision detection of physical quantities,which strongly depends on the measurement situation at hand.The stylus ion trap,formed by two concentric cylinders over a ground plane,holds the promise of relatively simple structure and larger solid angle for optical access and fluorescence collection in comparison with the conventional ion traps.Here we report our fabrication and characterization of the first stylus ion trap constructed in China,aiming for studying quantum optics and sensing weak electric fields in the future.We have observed the stable confinement of the ion in the trapping potential for more than two hours and measured the heating rate of the trap to be dε/dt=7.10±0.13 meV/s by the Doppler recooling method.Our work starts a way to building practical quantum sensors with high efficiency of optical collection and with ultimate goal for contributing to future quantum information technology.展开更多
文摘采用诱集法和单孢接种培养技术,自湖北省不同棉区的棉花根际土壤中分离到能在棉花上形成VA菌根的真菌孢子和孢子果,依其显微形态特征对大部分菌株进行了种的鉴定。在已鉴定到种的6个菌株中,除Glomus mosseae(Nicol.and Gerd.)Gerd.and Trappe和G.intraradices Schenck and Smith外,G.hoi Berch and Trappe.G.albidum Walker and Rhodes,G.ambisporum ⅡSmith and Schenck和G.geosporum(Nicol.and Gerd.)Walker4个种均为我国的新记录,其中G.albidam由于与Walker的描述不尽一致故命名为潜江变种(var.Qianjiang)。
文摘为研究高压直流(HVDC)输电系统中油纸绝缘的老化状态与空间电荷效应对其击穿特性的影响,采用加速热老化处理得到3种不同老化程度的油纸绝缘试样,通过同极性不同幅值的预压方式注入空间电荷,测量其击穿电压;采用电声脉冲法(PEA)在室温下观察试品的空间电荷分布,进一步分析了油纸内部的电场分布情况和陷阱分布特性。实验结果表明:经3 k V同极性预压后试品的击穿电压整体高于未经预压处理的试品;且随着油纸绝缘老化程度的加剧,介质内部浅陷阱密度增大;随着电荷注入量的逐渐增加、电荷效应的增强,击穿电压有所提高。但经4 k V同极性预压后试品的击穿电压整体低于经3 k V同极性预压后试品的击穿电压;因此,在实际运行中,同极性预压幅值超过一定阈值时反而会出现击穿电压降低的现象,应引起特别注意。
基金Project supported by the Special Project for Research and Development in Key Areas of Guangdong Province,China (Grant No.2020B0303300001)the National Natural Science Foundation of China (Grant Nos.U21A20434,12074346,12074390,11835011,11804375,and 11804308)+2 种基金the Fund from the Key Laboratory of Guangzhou for Quantum Precision Measurement (Grant No.202201000010)the Science and Technology Projects in Guangzhou (Grant No.202201011727)the Nansha Senior Leading Talent Team Technology Project (Grant No.2021CXTD02)。
文摘Cold trapped ions can be excellent sensors for ultra-precision detection of physical quantities,which strongly depends on the measurement situation at hand.The stylus ion trap,formed by two concentric cylinders over a ground plane,holds the promise of relatively simple structure and larger solid angle for optical access and fluorescence collection in comparison with the conventional ion traps.Here we report our fabrication and characterization of the first stylus ion trap constructed in China,aiming for studying quantum optics and sensing weak electric fields in the future.We have observed the stable confinement of the ion in the trapping potential for more than two hours and measured the heating rate of the trap to be dε/dt=7.10±0.13 meV/s by the Doppler recooling method.Our work starts a way to building practical quantum sensors with high efficiency of optical collection and with ultimate goal for contributing to future quantum information technology.
