Curing characteristics,morphology, thermal stability,mechanical properties,and irradiation resistance of methylethylsilicone/methylphenylsilicone rubber blends

Methylethylsilicone rubber (MESR)/methylphenylsilicone rubber (MPSR) blends were cured with 2,5‐dimethyl‐2,5‐di(tert‐butylperoxy)hexane. The curing characteristics, morphology, thermal behaviors, mechanical properties at different temperatures, radiation resistance, and thermal aging resistance of the MESR/MPSR blends were investigated. The results show that a high MPSR content could decrease the optimum curing time and improve the scorch safety. Dynamic mechanical analysis revealed that the glass‐transition temperature of the blends increased slightly with the addition of MPSR. Scanning electron microscopy showed that MESR and MPSR had good compatibility in the blends. Thermogravimetric analysis indicated that the thermal stability of the blends increased with increasing quantity of MPSR. The blends had excellent mechanical properties at low temperatures. However, these properties were significantly reduced when the temperature was increased. Moreover, changes in the mechanical properties decreased with increasing MPSR content at high temperatures, especially at temperatures higher than 100°C. In addition, the radiation resistance and thermal aging resistance of the blends increased with increasing MPSR content. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40529.     

基于矩阵相似变换的并行流水线CRC实现

研究了通用并行化循环冗余校验(CRC)编码结构,分析了限制编码速度提高的主要原因,根据多项式理论推导了并行CRC编码的一般化方法.在此基础上,根据线性代数中的有理标准型理论对编码结构中的反馈运算矩阵进行相似变换,提出了CRC编码的高速流水线并行结构,并设计实现了多种不同并行度下的CRC编码器.设计结果表明,高速流水线并行CRC编码器结构相对于其他结构具有最优的编码速度和最优的时序特性,可以满足高速数据完整性校验的需求.     

海洋环境下储油罐的防腐探究

通过对舟山地区油库的实地调查,分析海洋环境下温度湿度、大气中的盐类颗粒及微生物共同作用下的腐蚀环境的特点。舟山地区储油罐外腐蚀主要集中在底板区域和保温罐易积水部位,且底板外腐蚀情况较为常见。根据舟山地区储油罐外腐蚀的处理方法,探究得出适合海洋环境的防腐措施,主要有:选用合适的储油罐材料、构建合理的防腐涂料体系、合理利用阴极保护法以及建立完善的定期维护和日常保养制度等。     

河南油田超稠油油藏热化学辅助蒸汽吞吐技术研究

超稠油油藏开发是世界性难题,河南油田利用热化学辅助蒸汽吞吐技术成功实现了超稠油油藏的高效开发。分析了氮气和降黏剂改善蒸汽吞吐效果的机理,通过室内实验方法评价优选降黏剂,应用数值模拟方法进行了注汽强度、氮气注入量、降黏剂注入量等因素对开发效果影响的研究。该技术在河南油田超稠油油藏开发中得到了广泛应用,平均单井周期产油量提高117 t,含水率降低8%,油汽比提高0.12,取得了良好的开发效果,具有一定的借鉴意义。     

Receiver IQ Imbalance Estimation via Pure Noise for 60 GHz Systems

This paper proposes to estimate receiver (RX) IQ imbalance via pure noise for 60 GHz millimeter-wave systems. We study the impact of RX IQ imbalance on noise, and derive the maximum-likelihood algorithm to acquire the imbalance parameters, which is decoupled from transmitter IQ imbalance, channel response, and carrier offset. Also, the proposed method has low computational complexity and meets the low-power and low-cost requirements of 60 GHz systems. Moreover, the jitter performance of the estimation reaches the corresponding Cramer–Rao lower bound under a wide range of imbalance parameters.     

特大型滚子轴承支柱保持架优化设计

在分析了特大型滚子轴承支柱保持架失效模式的基础上,对支柱与垫片连接的螺纹连接端和焊接连接端分别进行了优化设计,大大降低了支柱保持架的失效概率。     

毛皮低温染色新方法的研究

本文在总结毛皮及相关行业（毛纺等）低温染色方法的基础上，对毛皮采用酸性染料低温染色进行了系统研究，尤其是对氧化─还原反应体系（即［Ｏ］／［Ｈ］体系）这一新方法用子毛皮醚性染料低温染色作了对比，筛选试验研究，并分析和讨论了试验结果，提出了最佳的［Ｏ］／［Ｈ］系统，配比及染色工艺方法，为毛皮低温染色开辟了一条新的途径。     

糙米安全储藏试验报告

本试验主要研究了糙米在自然缺氧、磷化铝低剂量和常规保管三种方式下的温湿度变化规律,氧浓度变化,害虫消长和微生物演替规律,品质变化及安全过夏的保鲜措施。通过对同一质量、同一储藏条件的稻米、大米、糙米进行对比试验,结果表明,采用低氧低药量储藏糙米能够抑制虫霉活动,糙米带菌量和浸染率小,品质变化正常,可以安全过夏。     

中国电信远程教育工程设计浅探

介绍多媒体技术在远程教育中的应用，中国电信远程教育教育网的组成方式。提出了对网络的环境要求、系统设计、平面设计、设备要求等问题。     

A two stage approach for channel transmission rate aware scheduling in directional mmWave WPANs

Millimeter wave (mmWave) communications in 60 GHz band have become a hot topic in wireless communications. New medium access control (MAC) protocols are needed because of the fundamental differences between mmWave communications and existing other communication systems. In mmWave wireless personal area networks, the channel transmission rates of links vary significantly because of the difference in the distance between nodes, the accuracy of beamforming, and the existence of obstructions. Owning to the directivity of mmWave links, spatial reuse should be exploited to improve network capacity. In this paper, we develop a channel transmission rate aware directional MAC protocol, termed RDMAC, in which both the multirate capability of links and spatial reuse are exploited to improve network performance. RDMAC has two stages. The first stage measures the channel transmission rates of links, and a heuristic algorithm is proposed to compute near‐optimal measurement schedules with respect to the total number of measurements. The second stage accommodates the traffic demand of links, and a heuristic transmission scheduling algorithm is proposed to compute near‐optimal transmission schedules with respect to the total transmission time. Simulations under various traffic modes show that compared with existing protocols, RDMAC has lower network latency, higher network throughput, and also a good fairness performance. Copyright © 2014 John Wiley & Sons, Ltd.