模拟数字电视信号同缆传输的调试问题

有线数字电视整转过渡期间,模拟、数字电视信号同缆传输将会存在一段时间,如何尽量减少模拟、数字两种电视信号的相互干扰是至关重要的问题,这里包括对机房前端的信号调制、网络传输的技术指标分配、终端接收的信号调节等环节,必须严格执行有关的技术规范。     

An A/D interface based on ∑Δ modulator for thermal vacuum sensor ASICs

A new ∑Δ modulator architecture for thermal vacuum sensor ASICs is proposed.The micro-hotplate thermal vacuum sensor fabricated by surface-micromachining technology can detect the gas pressure from 1 to 105 Pa.The amplified differential output voltage signal of the sensor feeds to the ∑Δ modulator to be converted into digital domain.The presented ∑Δ modulator makes use of a feed-forward path to suppress the harmonic distortions and attain high linearity.Compared with other feed-forward architectures presented before,the circuit complexity,chip area and power dissipation of the proposed architecture are significantly decreased.The correlated double sampling technique is introduced in the 1st integrator to reduce the flicker noise.The measurement results demonstrate that the modulator achieves an SNDR of 79.7 dB and a DR of 80 dB over a bandwidth of 7.8 kHz at a sampling rate of 4 MHz.The circuit has been fabricated in a 0.5μm 2P3M standard CMOS technology.It occupies an area of 5 mm2 and dissipates9 mW from a single 3 V power supply.The performance of the modulator meets the requirements of the considered application.     

基于电荷耦合器件的雷达视频积累电路

电荷耦合器件是一种发展前景良好的金属氧化物半导体（MOS）集成电路。该电路广泛应用于彩色成像、信号处理等相关领域。文介绍一种用CCD321型电荷藕合器件设计和实现的脉冲雷达视频积累电路,目的在于探讨使用该器件实现雷达视频积累的可行性和实际效果。实践证明,使用该器件实现雷达信号积累能有效地提高雷达的信噪比,改善雷达的检测能力,达到增加雷达的发现概率和探测距离的目的。经测试,使用该电路可使雷达信噪比可提高3．5dB。     

Ⅱ类变压器的绝缘要求和试验

依据标准 GB 19212.1—2003,对Ⅱ类变压器的绝缘要求和试验进行归纳总结,给出绝缘电阻、介电强度、爬电距离、电气间隙和穿过绝缘的距离的测试方法。     

激光熔凝NiAl/纳米Al2O3化学复合镀层抗高温氧化性能

采用大功率连续横流CO2激光对化学复合镀NiAl/纳米Al2O3复合镀层进行激光熔凝处理,并对熔凝层的抗高温氧化性能进行研究。采用X射线衍射仪(XRD)、扫描电镜(SEM)和能谱仪(EDS)等分别对高温氧化前后的表面形貌、物相组织和元素组成进行表征分析。与复合镀层和基体试样相比,激光熔凝后表面抗高温氧化性能明显提高,这一方面与激光熔凝镀层中的金属间化合物NiAl2O4、Ni0.77AlFe0.23在800℃时具有良好的抗高温氧化性有关,另一方面是由于激光熔凝后镀层表面形成了连续致密的氧化膜。     

Improved Quantum Yield and Excellent Luminescence Stability of Europium‐Incorporated Polymeric Hydrogen‐Bonded Heptazine Frameworks Due to an Efficient Hydrogen‐Bonding Effect

Two of the most persistent challenges for the high‐end application of luminescent lanthanide (Ln) compounds are a low quantum yield and luminescence quenching caused by a liquid medium. In this work, a type of polymeric hydrogen‐bonded heptazine framework is developed incorporating trivalent europium ions (P‐HHF‐Eu) via a low‐cost and facile low‐temperature thermal condensation reaction. Structural characterization clearly reveals that the solid‐phase pyrolyzation reaction results in the formation of P‐HHF‐Eu. Using time‐resolved and steady state photoluminescence (PL) spectroscopies, the photophysics and photochemistry of P‐HHF‐Eu at different hydration degrees are investigated and the role of hydrogen bonding in the significant enhancement of the emission properties is demonstrated. Furthermore, the P‐HHF‐Eu particles suspended in polyvinyl alcohol hydrogel exhibit excellent luminescence stability with a high PL quantum yield of up to ≈46% and wavelength responsive color‐tunable emission, which holds potential for security applications.     

一种基于家宽网络故障与业务的精准关联技术

在运营商故障监控工作中,OLT退服告警对宽带业务影响范围、家宽实际影响用户数一直是家宽业务关联影响的重要环节,明确OLT退服影响是告警监控重要的目标。提出一种基于家宽网络故障与业务的精准关联技术,将家宽用户信息与告警相结合,实现故障与影响客业务的网络指标自动关联,完成对OLT退服对业务的影响、影响用户精准分析和用户投诉的分析关联,减少用户投诉,提升用户满意度,实现经济效益的提升。     

锗掺杂磁控直拉单晶硅太阳电池

介绍了锗掺杂浓度为（1～1.5) E19cm-3的10Ω·cm磁控直拉单晶硅衬底上BSFR (back surface field and reflection）和BSR(back surface reflection)太阳电池的制备和电性能. BSR锗掺杂单晶硅太阳电池的AM0效率最高为12.3%. BSFR锗掺杂单晶硅太阳电池的AM0效率达到15%. 利用1MeV的高能电子对制备的锗掺杂单晶硅太阳电池进行了辐照实验. 作为对比，对全部常规10Ω·cm的CZ单晶硅太阳电池也进行了实验. 结果表明，锗掺杂浓度为（1～1.5)E19cm-3的磁控直拉单晶硅太阳电池的电性能和抗辐照性能与常规直拉硅太阳电池基本相同. 利用锗掺杂磁控直拉单晶硅片机械强度较高的优点，可以降低太阳电池生产过程破损率.     

110kV某变电站电容式电压互感器的故障分析

通过对110kV某变电站的故障电容式电压互感器进行现场检查、电气试验等,逐步对其进行分析,找出发生缺陷的根本原因。