晶型可控纳米银合成的简单方法及表征

晶型可控纳米银的合成正受到越来越多的关注,采用液相化学还原法,在温和的水溶液中用水合肼还原AgNO3,PVP作保护剂,单纯改变加料方式,成功制备了球形、三角形、六边形、圆盘状等均一或者混合形貌的纳米银分散液,用粒度分析仪、紫外-可见光分光光度计(UV-Vis)、扫描电子显微镜(SEM)等进行表征。结果表明,随着加料方式的改变,得到了球形,球形与片状共存的纳米银分散液,片状纳米银颗粒比例占到50%左右。     

专用型运算放大器在精密仪器仪表中的应用

对精密运放、高速运放、低噪声运放、视频运放等专用型运算放大器及其在仪器仪表中的应用技术进行了分析讨论，给出了几种典型应用实例，具有较高的实用价值。     

集成运放的互阻抗放大技术应用

本文对集成运放在电子技术应用中互阻抗放大技术进行了分析讨论，给出了相应的典型应用实例，具有重要的推广应用价值。     

1-Wire单总线器件技术规范及应用研究

1-Wire单总线是一种特殊串行数据通信方式,它具有结构简单、成本低廉、节省I/O资源、便于总线扩展和维护等优点。文章介绍了1-Wire单总线器件的若干技术规范及其应用设计,给出了单总线传感器件的典型应用电路实例,并分析了1-Wire单总线器件实际应用中存在的问题。     

浅析化工事故的发生规律及预防对策

针对我国化工生产和使用领域,重特大事故频繁发生,分析了事放原因,探究了化工事故的发生规律,并提出了预防对策,对遏制事故的发生,减少事故造成的损失提供有益参考。     

色散平坦光纤中的高速率PM-16QAM信号传输研究

提出了一种高速率、偏振复用、正交幅度调制信号的色散平坦光纤传输系统,传输速率分别为160 Gbps和256 Gbps,调制格式为PM-16QAM。实验研究了色散平坦光纤链路系统的传输特性,并分别与非零色散位移光纤和标准单模光纤链路传输特性做了比较。实验结果表明,较低输入光功率情况下,PM-16QAM信号在160 Gbps传输50 km时,经色散平坦光纤传输后的误差矢量幅度EVM优于经非零色散位移光纤传输情况0.5%,比特误码率BER优于非零色散位移光纤传输情况两个数量级;色散平坦光纤链路能更好地衰减旁瓣噪声;256 Gbps传输50 km和75 km时,仅在色散平坦光纤链路传输后可以较好地解调出信号;传输距离越长,保持较好特性时输入光功率范围越小。对比160 Gbps和256 Gbps情况,高速率PM-16QAM信号在色散平坦光纤链路的传输特性优于非零色散位移光纤和标准单模光纤链路的传输特性,传输速率越高、传输距离越长效果越明显。     

A novel three-ring-core few-mode fiber with large effective area and low nonlinear coefficient

A novel three-ring-core few-mode fiber with large effective area and low nonlinear coefficient is proposed in this paper. The fiber characteristics based on the full-vector finite element method (FEM) with perfect matched layer boundary conditions show that four supermodes with large effective area, low nonlinear coefficient and low differential mode group delay (DMGD) are achieved. With the increase of input wavelength, the effective areas of three-ring-core few-mode fiber are increased, and the nonlinear coefficients are decreased. The bending losses are increased with the increase of input wavelength, and are decreased with the increase of bending radius. Moreover, the proposed fiber performs a nonlinear coefficient and DMGD flattened profile at a large wavelength range.     

A dispersion flattened fiber front-haul transmission system with high bitrate signal at low input optical power

We propose a dispersion flattened fiber (DFF) front-haul transmission system with high bitrate, polarization multiplexing (PM) and quadrature amplitude modulation (QAM) signal at low input optical power. The modulation format of the system is PM-16QAM, and the bitrate is 256 Gbit/s. The transmission characteristics over DFF link system are experimentally studied, which are compared with those over non-zero dispersion shifted fiber (NZDSF) link and standard single mode fiber (SSMF) link. The experimental results show that the error vector magnitude (EVM) of 256 Gbit/s and PM-16QAM signal over 25 km DFF link is 0.75% better than that over 25 km NZDSF link at least, and the bit error rate (BER) and Q-factor are much better than those of NZDSF. Their EVM and BER are both decreased with the increase of input optical power, and the Q-factor is increased. Those characteristics over 25 km SSMF are the worst at the same case. The larger the dispersion is, the more the constellation points are deviated from their respective centers and the worse the constellation characteristics are. The greater the attenuation of the DFF is, the smaller the input power of the DFF is, the more the constellation points are deviated from their centers and the worse the constellation characteristics are. This study provides a new idea and experimental support for long span front-haul propagation in mobile communication.     

集成运放在应用中若干技术问题的讨论

对集成运放及其在电子技术应用中出现的若干问题进行了分析讨论,给出了相应的典型应用实例,具有一定的实用价值,为电路设计者提供了有益参考。     

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 材质为42CrMo的钢管在加工过程中发生断裂,为了探索断裂的原因,应用光电直读光谱仪、光学显微镜、扫描电子显微镜对该钢管断裂处进行了化学成分、宏观、微观等分析。研究结果表明：钢管的化学成分符合产品的技术要求,钢管断裂主要是由于钢管枝晶粗大和热处理工艺不当所致。