TD-LTE与WLAN共室分系统干扰分析与研究

随着TD-LTE与WLAN系统共室内分布成为一种必然趋势,二者之间在2.4 GHz邻频组网所面临的干扰也成为焦点问题。在分析了TD-LTE与WLAN系统共室分所面临的杂散干扰、阻塞干扰和互调干扰的基础上,进行了实际的WLAN与LTE共室分干扰测试和独立部署干扰测试,并对测试结果进行分析,提出了有效的干扰规避方案,重点分析了采用合路的方案。     

无线音乐基地移动互联网业务平台架构演进方案

移动互联网业务正逐步成为整个中国移动的重点业务,无线音乐基地是中国移动自有移动互联网业务的重要示范。移动互联网业务平台IT架构的好坏是保证音乐业务能否快速发展的前提。本文在分析无线音乐基地IT架构现状的基础上,结合移动互联网业界IT架构技术和理念的发展趋势,探讨了无线音乐基地IT架构的演进方案。     

A fitted numerical method for parabolic turning point singularly perturbed problems with an interior layer

The objective of this paper is to construct and analyze a fitted operator finite difference method (FOFDM) for the family of time‐dependent singularly perturbed parabolic convection–diffusion problems. The solution to the problems we consider exhibits an interior layer due to the presence of a turning point. We first establish sharp bounds on the solution and its derivatives. Then, we discretize the time variable using the classical Euler method. This results in a system of singularly perturbed interior layer two‐point boundary value problems. We propose a FOFDM to solve the system above. Through a rigorous error analysis, we show that the scheme is uniformly convergent of order one with respect to both time and space variables. Moreover, we apply Richardson extrapolation to enhance the accuracy and the order of convergence of the proposed scheme. Numerical investigations are carried out to demonstrate the efficacy and robustness of the scheme.     

ARINC429总线的故障注入测试方法

传统的ARINC429总线测试仅针对输入的激励测试输出的响应, 无法有效涵盖更多在异常状态下的测试环境。为扩大测试的覆盖性与主动性, 采用故障注入的方法, 分别对ARINC429总线物理层、电气层和协议层中典型的故障模式及注入实现方法进行了研究, 实验结果验证了故障注入测试方法的有效性。     

Efficiency enhancement in tandem organic light-emitting devices with a hybrid charge generation layer composed of BEDT-TTF-doped TPBi/mCP/HAT-CN

Tandem organic light-emitting devices (OLEDs) were fabricated with a hybrid organic charge generation layer (CGL) composed of bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF) doped 1,3,5-tris(N-phenylbenzimiazole-2-yl)benzene (TPBi), 1,3-bis(cabazol-9-yl)benzene (mCP), and 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HAT-CN) in an attempt to enhance their current efficiency. While the operating voltage of the tandem OLEDs with a hybrid structure composed of BEDT-TTF-doped TPBi, mCP, and a HAT-CN CGL at 10 mA/cm² was 1 V lower than that of the tandem OLEDs with a typical CGL composed of BEDT-TTF-doped TPBi and a HAT-CN, the corresponding the current efficiency of the tandem OLEDs with a hybrid CGL at 10 mA/cm² was 2.9 cd/A higher than that of the tandem OLEDs with a typical CGL. The increase in the current efficiency and the decrease in the operating voltage of the tandem OLEDs with the hybrid CGL were attributed to enhanced electron injection due to the insertion of the mCP layer into the hybrid CGL.     

Effect of oxygen plasma treatment on air exposed MoOx thin film

Oxygen plasma (OP) treatment on air exposed molybdenum oxide (MoO_x) has been investigated with ultraviolet photoemission spectroscopy (UPS) and angle resolved X-ray photoemission spectroscopy (AR-XPS). It was found that the work function (WF) reduction of MoO_x by air exposure can be recovered partially by OP treatment on the surface. The overall recovery was measured to be slightly more than 64%, which was adequate to provide a hole extraction layer to many hole-conducting organic materials. The incompleteness of the WF recovery could be attributed to the formation of a very thin layer of oxygen rich absorbents on top of the evaporated MoO_x film after OP treatment. AR-XPS showed that OP treatment shifted the core levels of oxygen and molybdenum about 0.1 eV toward the lower binding energy (BE), and confirmed the existence of oxygen deficiency in the evaporated MoO_x film. We also investigated the electronic energy level evolution of copper phthalocyanine (CuPc) on MoO_x/ITO by UPS. With the deposition of CuPc on OP treated MoO_x we observed band bending and the highest occupied molecular orbital (HOMO) level of CuPc was almost pinned to the Fermi level, which indicates the possibility of efficient hole injection with the OP treated MoO_x film.     

Constructing a novel single-layer white organic light-emitting device through a new sky-blue fluorescent bipolar host

A novel device concept was realized for simple single-layer small-molecule white organic light emitting devices. The single organic active layer here is simply comprised of a newly synthesized sky-blue fluorescent bipolar host (TPASO) and a common orange phosphorescent dopant. Suppressed singlet Föster energy transfer induced by a low-concentration doping and spontaneous high- to low-lying triplet energy transfer, respectively, lead to sky-blue fluorescence from TPASO and orange phosphorescence from the dopant. The resulting two-organic-component device exhibits a low turn-on voltage of 2.4 V, maximum current/power efficiencies up to 11.27 ± 0.02 cd A⁻¹ and 14.15 ± 0.03 lm W⁻¹, and a warm-white CIE coordinate of (0.42, 0.45) at 1000 cd m⁻².     

Sub-100 nm ALD-assisted nanoimprint lithography for realizing vertical organic transistors with high ON/OFF ratio and high output current

We introduced a conformal atomic-layer-deposited aluminum oxide layer to cover the imprint mold to reduce the feature size and to strengthen the mold durability. A nano-hole array pattern with diameter down to 85 nm was successfully transferred to sample substrate to fabricate a vertical organic transistor. The Imprint vertical organic transistor exhibited high output current density as 4.35 cm²/V s and high ON/OFF current ratio as 11,000 at a low operation voltage as 1.5 V.     

Effects of ultraviolet–ozone treatment on organic-stabilized ZnO nanoparticle-based electron transporting layers in inverted polymer solar cells

Electron transporting layers (ETLs) in inverted polymer solar cells (I-PSCs) were fabricated by spin coating a colloidal dispersion of ZnO nanoparticles (NPs), and the effects of ultraviolet–ozone (UVO) treatment on the ZnO NP ETLs were investigated. The brief UVO treatment (<5 min) could considerably improve the performance of the resulting I-PSCs (∼30% increase in power conversion efficiency); whereas, excessive UVO treatment (>10 min) caused significant degradation. The characterization of the ZnO ETLs as a function of the UVO treatment duration revealed that brief treatment can remove the residual organic stabilizer molecules on the surface of the ZnO films by UV induced decomposition mechanism. However, excessive treatment can generate additional defects on/within the ZnO films, which can induce charge recombination. This effect was further confirmed by the thermal treatment of the ZnO ETLs at a high temperature (280 °C) at which the organic surfactants could be removed. Flexible I-PSCs were also fabricated using indium doped tin oxide coated plastic substrates and the usefulness of the room temperature UVO treatment was further confirmed in view of its potential applicability in flexible devices.     

Direct observation of ICT cations at the HTL/transparent semiconductor interface

The cation density at the interface of a transparent anode and an organic layer has been measured for several hole transport (HT) materials. The number of cations at the interface of ITO:MoO_x with rubrene, NPB, m-MTDATA and TCTA was found to range from 8 × 10¹³ to 1.5 × 10¹⁴ per cm² in freshly prepared devices. These values decreased by about 25% after one month. These cations are part of the dipole layer that results from the transfer of electrons from an organic layer, whose adiabatic ionization potential is less than the work function of the anode.