Terahertz Direct Modulation Techniques for High-speed Communication Systems

Terahertz communication technology can provide abundant frequency resources,strong confidentiality,antijamming capability,communication tracking capability and ...     

ETFE薄膜在游泳馆中应用的防结露分析

通过分析围护结构不同部位发生结露的主要原因,有针对性地给出了防结露的解决方案,保证了游泳馆的正常使用。为双层薄膜围护结构系统的防结露设计提供了理论参考。     

Three-dimensional graphene and its composite for gas sensors

As a two-dimensional (2D) material,graphene shows excellent advantages in the field of gas sensors due to its inherent large specific surface area and unique el...     

SO_4~（2－）／ZrO_2超强酸催化剂的结构表征

用ＢＥＴ法分析了制备条件对ＳＯ＿４￣（２－）／ＺｒＯ＿２超强酸催化剂的比表面和孔结构的影响，用ＳＥＭ观察了催化剂的表面形貌。结果表明，引人ＳＯ＿４￣（２－）后催化剂的比表面和比表面的热稳定性都增大了，在Ｈ＿２ＳＯ＿４浓度为１．０ｍｏｌ／１和焙烧温度约７７３Ｋ时催化剂的比表面较大。制备Ｚｒ（ＯＨ）＿４时用浓氨水得到的催化剂的比表面、平均孔径和孔体积都较大。ＳＯ＿４￣（２－）／ＺｒＯ＿２催化剂的孔为平均孔径３－５ｎｍ的中孔。ＳＥＭ结果表明，ＳＯ＿４￣（２－）／ＺｒＯ＿２催化剂的表面为很不平整的蜂窝状。     

Hierarchical Magnetic Network Constructed by CoFe Nanoparticles Suspended Within “Tubes on Rods” Matrix Toward Enhanced Microwave Absorption

Hierarchical magnetic-dielectric composites are promising functional materials with prospective applications in microwave absorption(MA)field.Herein,a three-dimension hierarchical“nanotubes on microrods,”core–shell magnetic metal–carbon composite is rationally constructed for the first time via a fast metal–organic frameworksbased ligand exchange strategy followed by a carbonization treatment with melamine.Abundant magnetic CoFe nanoparticles are embedded within one-dimensional graphitized carbon/carbon nanotubes supported on micro-scale Mo2N rod(Mo2N@CoFe@C/CNT),constructing a special multi-dimension hierarchical MA material.Ligand exchange reaction is found to determine the formation of hierarchical magnetic-dielectric composite,which is assembled by dielectric Mo2N as core and spatially dispersed CoFe nanoparticles within C/CNTs as shell.Mo2N@CoFe@C/CNT composites exhibit superior MA performance with maximum reflection loss of−53.5 dB at 2 mm thickness and show a broad effective absorption bandwidth of 5.0 GHz.The Mo2N@CoFe@C/CNT composites hold the following advantages:(1)hierarchical core–shell structure offers plentiful of heterojunction interfaces and triggers interfacial polarization,(2)unique electronic migration/hop paths in the graphitized C/CNTs and Mo2N rod facilitate conductive loss,(3)highly dispersed magnetic CoFe nanoparticles within“tubes on rods”matrix build multi-scale magnetic coupling network and reinforce magnetic response capability,confirmed by the off-axis electron holography.     

Blue Luminescence of ZnO Nanoparticles Based on Non‐Equilibrium Processes: Defect Origins and Emission Controls

High concentrations of defects are introduced into nanoscale ZnO through non‐equilibrium processes and resultant blue emissions are comprehensively analyzed, focusing on defect origins and broad controls. Some ZnO nanoparticles exhibit very strong blue emissions, the intensity of which first increase and then decrease with annealing. These visible emissions exhibit strong and interesting excitation dependences: 1) the optimal excitation energy for blue emissions is near the bandgap energy, but the effective excitation can obviously be lower, even 420 nm (2.95 eV < E_g = 3.26 eV); in contrast, green emissions can be excited only by energies larger than the bandgap energy; and, 2) there are several fixed emitting wavelengths at 415, 440, 455 and 488 nm in the blue wave band, which exhibit considerable stability in different excitation and annealing conditions. Mechanisms for blue emissions from ZnO are proposed with interstitial‐zinc‐related defect levels as initial states. EPR spectra reveal the predominance of interstitial zinc in as‐prepared samples, and the evolutions of coexisting interstitial zinc and oxygen vacancies with annealing. Furthermore, good controllability of visible emissions is achieved, including the co‐emission of blue and green emissions and peak adjustment from blue to yellow.     

Effectiveness and petroleum geological significance of tectonic fractures in the ultra-deep zone of the Kuqa foreland thrust belt:a case study of the Cretaceous Bashijiqike Formation in the Keshen gas field

The buried depth of the gas-producing reservoir in the Kuqa foreland thrust belt of the Tarim Basin exceeds 6000 m.The average matrix porosity of the reservoir ...     

Advances and Challenges in Two?Dimensional Organic–Inorganic Hybrid Perovskites Toward High?Performance Light?Emitting Diodes

Two-dimensional (2D) perovskites are known as one of the most promising luminescent materials due to their structural diversity and outstanding optoelectronic p...     

实时数据库压缩死区的研究

厂级监控信息系统(SIS)要处理大量的数据,原始数据不处理就去存储,要耗费大量的磁盘空间。介绍了实时历史数据库里的例外报告技术,应用这种技术,对电厂里的数据特性进行了分析。通过大量数据的统计分析,找出数据本身的特性,为例外报告技术死区的设置提供依据。统计了山西漳山电厂2008年10～12月共85 248个数据,得出了某个温度信号的特性,并绘制了相应曲线,死区设置可以将曲线作为参考。