DME设备大量应用于航路导航和进近着陆,其工作原理为通过测量机载设备与地面设备之间询问应答脉冲的传播时间而测出飞机到地面台的距离。Selex公司制造的1119A型DME设备为地面设备,相较于传统DME设备,其硬件集成度和数字化程度更高,维...DME设备大量应用于航路导航和进近着陆,其工作原理为通过测量机载设备与地面设备之间询问应答脉冲的传播时间而测出飞机到地面台的距离。Selex公司制造的1119A型DME设备为地面设备,相较于传统DME设备,其硬件集成度和数字化程度更高,维护更复杂。本文深入分析了1119A型DME设备的完整性检测预警(Integrity Test Alert)故障处理流程,通过详细梳理和总结经验,旨在提升导航设备维护中的安全管理能力,提高维修人员对新型设备的故障处理能力,确保在设备出现故障时能够迅速、准确地发现问题并加以解决,进一步巩固和强化整个航空安全建设。展开更多
Exploiting high-performance electrolyte holds the key for realization practical application of rechargeable magnesium batteries(RMBs).Herein,a new non-nucleophilic mononuclear electrolyte was developed and its electro...Exploiting high-performance electrolyte holds the key for realization practical application of rechargeable magnesium batteries(RMBs).Herein,a new non-nucleophilic mononuclear electrolyte was developed and its electrochemical active species was identified as[Mg(DME)_(3)][GaCl_(4)]_(2) through single-crystal X-ray diffraction analysis.The as-synthesized Mg(GaCl_(4))_(2)-IL-DME electrolyte could achieve a high ionic conductivity(9.85 m S cm^(-1)),good anodic stability(2.9 V vs.Mg/Mg^(2+)),and highly reversible Mg plating/stripping.The remarkable electrochemical performance should be attributed to the in-situ formation of Mg^(2+)-conducting Ga_(5)Mg_(2)alloy layer at the Mg/electrolyte interface during electrochemical cycling,which not only efficiently protects the Mg anode from passivation,but also allows for rapid Mg-ion transport.Significantly,the Mg(GaCl_(4))_(2)-IL-DME electrolyte showed excellent compatibility with both conversion and intercalation cathodes.The Mg/S batteries with Mg(Ga Cl_(4))_(2)-IL-DME electrolyte and KB/S cathode showed a high specific capacity of 839 m Ah g^(-1)after 50 cycles at 0.1 C with the Coulombic efficiency of~100%.Moreover,the assembled Mg|Mo_6 S_8 batteries delivered a reversible discharge capacity of 85 m Ah g^(-1)after 120 cycles at 0.2 C.This work provides a universal electrolyte for the realization of high-performance and practical RMBs,especially Mg/S batteries.展开更多
针对测距仪(distance measure equipment,DME)信号严重干扰L频段数字航空通信系统(L-band digital aviation communication system,L-DACS)前向链路接收机的问题,提出基于相关稀疏变分贝叶斯(correlated sparse variational Bayesian,cS...针对测距仪(distance measure equipment,DME)信号严重干扰L频段数字航空通信系统(L-band digital aviation communication system,L-DACS)前向链路接收机的问题,提出基于相关稀疏变分贝叶斯(correlated sparse variational Bayesian,cSVB)算法的DME脉冲干扰抑制方法。所提方法利用L-DACS系统正交频分复用(orthogonal frequency division multiplexing,OFDM)接收机的空子载波信息构建接收信号的压缩感知方程;然后,根据cSVB算法进行三层次贝叶斯信号建模,最后选择了两种变体算法重构DME干扰信号,并将其从时域接收信号中去除。理论分析与仿真结果表明,所提出的干扰抑制方法可以充分利用信号先验信息,进一步降低DME干扰信号估计的归一化均方误差,有效改善L-DACS系统的误码性能,提高传输可靠性。展开更多
The catalytic conversion of methanol to dimethylether(DME)was studied over CuO/Al2O3,ZnO/Al2O3and ZnOCuO/Al2O3nanocatalysts prepared in presence or absence of ultrasonic irradiation.The catalysts were characterized by...The catalytic conversion of methanol to dimethylether(DME)was studied over CuO/Al2O3,ZnO/Al2O3and ZnOCuO/Al2O3nanocatalysts prepared in presence or absence of ultrasonic irradiation.The catalysts were characterized by X-ray diffraction(XRD),surface characterization method(BET),scanning electron microscope(SEM),H2-temperature programmed reduction(H2-TPR)and temperature programmed desorption of ammonia(NH3-TPD).The experimental results show that during catalytic dehydration of methanol to dimethylether,the activities of the CuO/Al2O3,ZnO/Al2O3and ZnO-CuO/Al2O3catalysts prepared using ultrasonic treatment are much higher than those prepared in absence of ultrasonication.SEM shows that the use of ultrasonication results in much smaller nanoparticles.BET and XRD show that the ultrasonication increases the surface area and pore volume of the catalysts.H2-TPR profiles indicated that reducibility of the sonicated nanocatalysts is carried out at lower temperatures.NH3-TPD shows that ultrasound irradiation has enhanced the acidity of the nanocatalyst and hence enhanced catalytic performance for DME formation.展开更多
Patents and previous research concerning the single-step synthesis of DME were reviewed. Rapid deactivation of the bifunctional catalyst is the main issue for the commercialization of the single-step synthesis process...Patents and previous research concerning the single-step synthesis of DME were reviewed. Rapid deactivation of the bifunctional catalyst is the main issue for the commercialization of the single-step synthesis process; in addition, the separation process and utilization of by-products have a larger impact on economic performance of the process. Recent progress involving the development of bifunctional catalysts and separation technology in the single-step process will most likely make the process commercially available in the near future.展开更多
针对当前地面测距机(DME)导航台的作用范围一般为200 n miles左右[3],飞机在航行过程中往往需要经过多个DME导航台,而传统的机载DME设备只能工作在单频率下,这就需要飞行员手动切换对应地面台的频率,从而增加了飞行员工作量的问题。本...针对当前地面测距机(DME)导航台的作用范围一般为200 n miles左右[3],飞机在航行过程中往往需要经过多个DME导航台,而传统的机载DME设备只能工作在单频率下,这就需要飞行员手动切换对应地面台的频率,从而增加了飞行员工作量的问题。本文从实际工程应用出发,通过对机载DME设备工作过程进行分析,提出多台轮询技术,研究并实现直接扫描和自由扫描两种模式情况,该技术可提高航路定位的精准性,减少飞行员工作量。展开更多
文摘DME设备大量应用于航路导航和进近着陆,其工作原理为通过测量机载设备与地面设备之间询问应答脉冲的传播时间而测出飞机到地面台的距离。Selex公司制造的1119A型DME设备为地面设备,相较于传统DME设备,其硬件集成度和数字化程度更高,维护更复杂。本文深入分析了1119A型DME设备的完整性检测预警(Integrity Test Alert)故障处理流程,通过详细梳理和总结经验,旨在提升导航设备维护中的安全管理能力,提高维修人员对新型设备的故障处理能力,确保在设备出现故障时能够迅速、准确地发现问题并加以解决,进一步巩固和强化整个航空安全建设。
基金financially supported by National Natural Science Foundation of China(21773291,52303130,62205231,61904118,22002102)Natural Science Foundation of the Jiangsu Higher Education Institutions of China(19KJA210005)+1 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(SJCX23_1710)Postgraduate Research&Practice Innovation Program of Suzhou University of Science and Technology(CLKYCX23_06)。
文摘Exploiting high-performance electrolyte holds the key for realization practical application of rechargeable magnesium batteries(RMBs).Herein,a new non-nucleophilic mononuclear electrolyte was developed and its electrochemical active species was identified as[Mg(DME)_(3)][GaCl_(4)]_(2) through single-crystal X-ray diffraction analysis.The as-synthesized Mg(GaCl_(4))_(2)-IL-DME electrolyte could achieve a high ionic conductivity(9.85 m S cm^(-1)),good anodic stability(2.9 V vs.Mg/Mg^(2+)),and highly reversible Mg plating/stripping.The remarkable electrochemical performance should be attributed to the in-situ formation of Mg^(2+)-conducting Ga_(5)Mg_(2)alloy layer at the Mg/electrolyte interface during electrochemical cycling,which not only efficiently protects the Mg anode from passivation,but also allows for rapid Mg-ion transport.Significantly,the Mg(GaCl_(4))_(2)-IL-DME electrolyte showed excellent compatibility with both conversion and intercalation cathodes.The Mg/S batteries with Mg(Ga Cl_(4))_(2)-IL-DME electrolyte and KB/S cathode showed a high specific capacity of 839 m Ah g^(-1)after 50 cycles at 0.1 C with the Coulombic efficiency of~100%.Moreover,the assembled Mg|Mo_6 S_8 batteries delivered a reversible discharge capacity of 85 m Ah g^(-1)after 120 cycles at 0.2 C.This work provides a universal electrolyte for the realization of high-performance and practical RMBs,especially Mg/S batteries.
文摘针对测距仪(distance measure equipment,DME)信号严重干扰L频段数字航空通信系统(L-band digital aviation communication system,L-DACS)前向链路接收机的问题,提出基于相关稀疏变分贝叶斯(correlated sparse variational Bayesian,cSVB)算法的DME脉冲干扰抑制方法。所提方法利用L-DACS系统正交频分复用(orthogonal frequency division multiplexing,OFDM)接收机的空子载波信息构建接收信号的压缩感知方程;然后,根据cSVB算法进行三层次贝叶斯信号建模,最后选择了两种变体算法重构DME干扰信号,并将其从时域接收信号中去除。理论分析与仿真结果表明,所提出的干扰抑制方法可以充分利用信号先验信息,进一步降低DME干扰信号估计的归一化均方误差,有效改善L-DACS系统的误码性能,提高传输可靠性。
文摘The catalytic conversion of methanol to dimethylether(DME)was studied over CuO/Al2O3,ZnO/Al2O3and ZnOCuO/Al2O3nanocatalysts prepared in presence or absence of ultrasonic irradiation.The catalysts were characterized by X-ray diffraction(XRD),surface characterization method(BET),scanning electron microscope(SEM),H2-temperature programmed reduction(H2-TPR)and temperature programmed desorption of ammonia(NH3-TPD).The experimental results show that during catalytic dehydration of methanol to dimethylether,the activities of the CuO/Al2O3,ZnO/Al2O3and ZnO-CuO/Al2O3catalysts prepared using ultrasonic treatment are much higher than those prepared in absence of ultrasonication.SEM shows that the use of ultrasonication results in much smaller nanoparticles.BET and XRD show that the ultrasonication increases the surface area and pore volume of the catalysts.H2-TPR profiles indicated that reducibility of the sonicated nanocatalysts is carried out at lower temperatures.NH3-TPD shows that ultrasound irradiation has enhanced the acidity of the nanocatalyst and hence enhanced catalytic performance for DME formation.
文摘Patents and previous research concerning the single-step synthesis of DME were reviewed. Rapid deactivation of the bifunctional catalyst is the main issue for the commercialization of the single-step synthesis process; in addition, the separation process and utilization of by-products have a larger impact on economic performance of the process. Recent progress involving the development of bifunctional catalysts and separation technology in the single-step process will most likely make the process commercially available in the near future.
文摘针对当前地面测距机(DME)导航台的作用范围一般为200 n miles左右[3],飞机在航行过程中往往需要经过多个DME导航台,而传统的机载DME设备只能工作在单频率下,这就需要飞行员手动切换对应地面台的频率,从而增加了飞行员工作量的问题。本文从实际工程应用出发,通过对机载DME设备工作过程进行分析,提出多台轮询技术,研究并实现直接扫描和自由扫描两种模式情况,该技术可提高航路定位的精准性,减少飞行员工作量。
