地市级地面数字电视发射机常见故障分析

随着中国加快推进地面数字电视（DTMB）无线覆盖工程的建设,提高技术人员对地面数字电视发射系统设备的维护维修水平、故障判断排除能力刻不容缓。本文结合由包头市微波总站建设的市级地面数字电视单频网项目,对其运行中常见的发射机故障进行了分析和总结。     

网络攻防模拟实验平台的设计与实现

针对网络攻防环境难以构建的难题,提出了基于虚拟环境的网络攻防模拟实验平台,给出了模拟实验平台的组成结构,分析了在该平台上开展网络攻防模拟实验过程和系统运行机制。分别对网络攻击子系统和网络防护子系统进行了详细设计,研究了两个子系统中采用的关键技术及实现方法。通过采用虚拟机技术,在服务器上虚拟出网络攻击和网络防护子系统,能够实现当前绝大多数的网路攻击操作以及网络防护的配置管理,能够为用户提供功能更为全面、性能更为优越、仿真程度更为逼真的网络攻防实验训练环境。     

变压器型式试验的样品组成和样品数量的确定(上)

研究和讨论了GB 19212.1-2003,5.2和附录B分别规定的单规格变压器的试验规则和"系列变压器的试验"规则,提出了确定变压器型式试验的样品组成和样品数量的一种可操作的方案.     

基于PUFS的不经意传输协议

不经意传输(OT, oblivious transfer）协议是密码学中的一个基本协议。基于物理不可克隆函数（PUF, physical unclonable function）给出物理不可克隆函数系统（PUFS, physical unclonable function system）的概念,并在此基础上提出一个新的不经意传输协议（POT, PUFS based OT）,最后在通用可组合（UC, universal composition）框架内给出POT协议抵抗静态敌手的安全性证明。相比于传统基于公钥加密的OT方案,POT协议不使用任何可计算的假设,而是基于PUFS的安全属性实现,因此在很大程度上减小了计算和通信开销。     

含油页岩不同极性试剂连续抽提物饱和烃组成特征

页岩中不同赋存状态原油的分离成为当前较为关注的问题。采用极性逐渐增强的正己烷、二氯甲烷和三氯甲烷对祁连山木里煤田钻孔的含油页岩样品进行连续抽提,对各抽提物分别做族组分和定量色谱—质谱分析。研究结果表明:正己烷冷浸泡抽提物主要为页岩内自由态烃类,以饱和烃为主;而三氯甲烷索氏抽提物则主要为吸附态烃类,其中极性组分含量高,且碳数较高的正构烷烃丰度高;随溶剂极性的增加,连续抽提物生标参数C_(29)ααα甾烷20S/(20S+20R)与C_(24)四环萜烷/C_(26)三环萜烷比值逐渐增加,而C_(21)/C_(23)三环萜烷比值逐渐减小,但C_(23)三环萜烷/C_(30)藿烷和C_(31)升藿烷22S/(22S+22R)比值基本保持不变,另外部分参数比值则表现为无规律性的变化;尽管各种抽提物烃类组成和分子参数存在一定的差异,但各类化合物分布模式和部分参数值差异很小,表明3种连续抽提物(不同赋存状态的烃类)均为页岩内本源烃,而非外来烃。     

Antimicrobial effects of cinnamon bark oil on microbial composition and quality of grass carp (Ctenopharyngodon idellus) fillets during chilled storage

In this study, 11 essential oils were initially screened for antimicrobial activity against Aeromonas veronii, Acinetobacter johnsonii, Shewanella putrefaciens, and Pseudomonas jessenii. Cinnamon bark oil exhibited the highest antimicrobial activity and was used as a natural preservative in grass carp fillets stored at 4 ± 1 °C. Sensory assessment, total volatile basic nitrogen (TVB-N), color, biogenic amines, adenosine triphosphate (ATP)-related compounds, K-value, and presence of microbiota were analyzed during storage. Cinnamon bark oil treatment was found to be effective in enhancing organoleptic quality, inhibiting microbial growth, and delaying the increase of TVB-N, putrescine, cadaverine and K-value. Based on sensory analysis, shelf-life of grass carp fillets was 8 days for the control and 12 days for the treatment group. According to high-throughput sequencing, Aeromonas and Pseudomonas were the predominant microbiota in fresh grass carp. As storage time progressed, the microbial composition of both control and treatment samples became less diverse. Pseudomonas followed by Aeromonas were dominant in spoiled control samples. However, there were significant differences in microbial composition between control and treatment samples at the end of storage. Cinnamon bark oil treatment inhibited the growth of Aeromonas and Shewanella, and Pseudomonas was the only predominant microbiota found in spoiled treatment samples.     

The influence of carbonate rock on the processes of oil transformation

The study of the processes of crude oil transformation in carbonate rock was carried out on the “oil – carbonate rock” model systems. For the study, oils of different chemical composition recovered from both terrigenous and carbonate reservoirs, and rock from carbonate reservoir were selected. It was shown that not all oils were subjected the catalytic action of carbonate rock. In oils that have experienced the catalytic action of carbonate rock the content of aromatic hydrocarbons decreased significantly and the content of non-polar resins increased. In carbonate rock, in addition to calcite and aragonite the montmorillonite was detected and it was supposed that the catalytic effect of the carbonate rock was due to this clay mineral. It was found that the oil transformation in the carbonate rock did not require much time and high temperature, and also that the oil recovered from the carbonate reservoir was resistant to the catalytic action of the carbonate rock.     

减压蜡油烃族组成的预测研究

根据国内外各种原油350~500℃减压蜡油馏分(VGO)质谱法烃族组成的分析数据,用带约束的最小二乘规划的方法,整理出根据油品的常规性质———平均沸点、密度、氢含量、分子量、折光和100℃运动黏度关联其烃族组成的关联式,可用于预测出较为详细的烃族组成,亦可换算为结构族组成,与现有的计算烃族组成和结构族组成的关联式相比预测精度有较大的提高。此外,还提出了根据已知VGO的烃族组成和平均沸点预测常规性质的关联式,这些关联式均达到了较高的关联精度。     

直拉法制备锑化铟单晶的表面杂质研究

制备高质量锑化铟(InSb)单晶是发展大规模红外焦平面器件以及新型高温红外探测器衬底材料的关键。而在用直拉法生长InSb的过程中,表面杂质的出现会严重影响成品率。利用X射线光电子能谱(X-ray Photoelectron Spectroscopy, XPS)技术研究了生产中InSb晶体表面杂质膜层的成分,分析了其主要来源及造成的影响,并采取相应工艺措施进行了改进。结果表明,InSb晶体表面杂质膜层的主要成分为In₂O₃、Sb₂O₃和Sb₂O₅三者的混合物以及碳沾污,其厚度不超过40 nm。通过对单晶炉处理和保护气氛的工艺优化,表面杂质大大减少,为获得高质量晶体奠定了基础。     

Photoelectric Synaptic Plasticity Realized by 2D Perovskite

Recently, several light‐stimulated artificial synaptic devices have been proposed to mimic photonic synaptic plasticity for neuromorphic computing. Here, the photoelectric synaptic plasticity based on 2D lead‐free perovskite ((PEA)₂SnI₄) is demonstrated. The devices show a photocurrent activation in response to a light stimulus in a neuron‐like way and exhibit several essential synaptic functions such as short‐term plasticity (STP) and long‐term plasticity (LTP) as well as their transmission based on spike frequency control. The strength of synaptic connectivity can be effectively modulated by the duration, irradiance, and wavelength of light spikes. The ternary structure of (PEA)₂SnI₄ causes it to possess varied photoelectric properties by composition control, which enhances the complexity and freedoms required by neuromorphic computing. The physical mechanisms of the memory effect are attributed to two distinct lifetimes of photogenerated carrier trapping/detrapping processes modulated by controlling the proportion of Sn vacancies. This work demonstrates the great potential of (PEA)₂SnI₄ as a platform to develop future multifunctional artificial neuromorphic systems.