We present a study on radiation losses in the microwave X band in Al-Cr substituted Y-type hexaferrites, namely Ba2Mg2Alx/2Crx/2Fe12-xO22 （x = 0, 0.5 and 1.0）. The study is performed by means of a vector network ana...We present a study on radiation losses in the microwave X band in Al-Cr substituted Y-type hexaferrites, namely Ba2Mg2Alx/2Crx/2Fe12-xO22 （x = 0, 0.5 and 1.0）. The study is performed by means of a vector network analyzer, Fourier transform infrared spectroscopy, a vibrating sample magnetometer and x-ray powder diffraction. Ba2Mg2Fe12O22 hexaferrite shows radiation loss of -37.25dB （99.999% loss） at frequency 9.81 GHz, which can be attributed to its high value of saturation magnetization, i.e., 22.08emu/g. Moreover, we obtain that magnetic properties have strong influence on the radiation losses.展开更多
At airports, runway operation is the limiting factor for the overall throughput; specifically the fixed and overly conservative ICAO wake turbulence separation minima. The wake turbulence hazardous flows can dissipate...At airports, runway operation is the limiting factor for the overall throughput; specifically the fixed and overly conservative ICAO wake turbulence separation minima. The wake turbulence hazardous flows can dissipate quicker because of decay due to air turbulence or be transported out of the way on oncoming traffic by cross-wind, yet wake turbulence separation minima do not take into account wind conditions. Indeed, for safety reasons, most airports assume a worst-case scenario and use conservative separations; the interval between aircraft taking off or landing therefore often amounts to several minutes. However, with the aid of accurate wind data and precise measurements of wake vortex by radar sensors, more efficient intervals can be set, particularly when weather conditions are stable. Depending on traffic volume, these adjustments can generate capacity gains, which have major commercial benefits. This paper presents the use of Electronic scanning radar for detecting wake vortices. In this method, the raindrops Doppler spectrogram is used to retrieve the strength of the wake vortex. Numerical simulation are performed to establish an empirical model used during the retrieval method. This paper presents also the results obtained during the trials of the PARIS-CDG data set recorded from October 2014 to November 2015 with an X-band RADAR developed and deployed by THALES.展开更多
钙钛矿材料由于具有结构稳定、易于获取、成本低廉和易于合成等优点,在发光二极管、激光器和太阳能电池等光电器件领域具有广阔的应用前景。目前,部分适合UV-LED应用的钙钛矿具有结构不稳定性。为了寻找结构稳定的钙钛矿,此项研究利用...钙钛矿材料由于具有结构稳定、易于获取、成本低廉和易于合成等优点,在发光二极管、激光器和太阳能电池等光电器件领域具有广阔的应用前景。目前,部分适合UV-LED应用的钙钛矿具有结构不稳定性。为了寻找结构稳定的钙钛矿,此项研究利用第一性原理对无铅双钙钛矿Cs_(2)NaScX_(6)(X=Cl,Br,I)的电子及光学性质进行了理论计算。计算结果表明:Cs_(2)NaScX_(6)(X=Cl,Br,I)为直接带隙半导体,带隙值分别为5.545 e V(Cl)、4.549 eV(Br)和3.408 eV(I),Cs_(2)NaScI_(6)在紫外光范围内具有较强的光吸收。本研究内容为无铅A_(2)B^(I)B^(III)X_(6)型双钙钛矿成为UV-LED的候选材料提供理论支持。展开更多
The silicon epitaxial wafter for X band double Read-type DDR IMPATT diodes has been fabricatedby normal-low pressure growth technique. The hyperabrupt impurity profile and very thin p-layer, n-layerwere achieved.
文摘We present a study on radiation losses in the microwave X band in Al-Cr substituted Y-type hexaferrites, namely Ba2Mg2Alx/2Crx/2Fe12-xO22 （x = 0, 0.5 and 1.0）. The study is performed by means of a vector network analyzer, Fourier transform infrared spectroscopy, a vibrating sample magnetometer and x-ray powder diffraction. Ba2Mg2Fe12O22 hexaferrite shows radiation loss of -37.25dB （99.999% loss） at frequency 9.81 GHz, which can be attributed to its high value of saturation magnetization, i.e., 22.08emu/g. Moreover, we obtain that magnetic properties have strong influence on the radiation losses.
文摘At airports, runway operation is the limiting factor for the overall throughput; specifically the fixed and overly conservative ICAO wake turbulence separation minima. The wake turbulence hazardous flows can dissipate quicker because of decay due to air turbulence or be transported out of the way on oncoming traffic by cross-wind, yet wake turbulence separation minima do not take into account wind conditions. Indeed, for safety reasons, most airports assume a worst-case scenario and use conservative separations; the interval between aircraft taking off or landing therefore often amounts to several minutes. However, with the aid of accurate wind data and precise measurements of wake vortex by radar sensors, more efficient intervals can be set, particularly when weather conditions are stable. Depending on traffic volume, these adjustments can generate capacity gains, which have major commercial benefits. This paper presents the use of Electronic scanning radar for detecting wake vortices. In this method, the raindrops Doppler spectrogram is used to retrieve the strength of the wake vortex. Numerical simulation are performed to establish an empirical model used during the retrieval method. This paper presents also the results obtained during the trials of the PARIS-CDG data set recorded from October 2014 to November 2015 with an X-band RADAR developed and deployed by THALES.
文摘钙钛矿材料由于具有结构稳定、易于获取、成本低廉和易于合成等优点,在发光二极管、激光器和太阳能电池等光电器件领域具有广阔的应用前景。目前,部分适合UV-LED应用的钙钛矿具有结构不稳定性。为了寻找结构稳定的钙钛矿,此项研究利用第一性原理对无铅双钙钛矿Cs_(2)NaScX_(6)(X=Cl,Br,I)的电子及光学性质进行了理论计算。计算结果表明:Cs_(2)NaScX_(6)(X=Cl,Br,I)为直接带隙半导体,带隙值分别为5.545 e V(Cl)、4.549 eV(Br)和3.408 eV(I),Cs_(2)NaScI_(6)在紫外光范围内具有较强的光吸收。本研究内容为无铅A_(2)B^(I)B^(III)X_(6)型双钙钛矿成为UV-LED的候选材料提供理论支持。
文摘The silicon epitaxial wafter for X band double Read-type DDR IMPATT diodes has been fabricatedby normal-low pressure growth technique. The hyperabrupt impurity profile and very thin p-layer, n-layerwere achieved.
