微纳米复合纤维深度再生绝缘油性能研究

绝缘油在持续高温、电场作用以及铜铁金属催化的影响下,会经历老化过程并生成各类杂质,干扰电气设备的稳定工作,因此,需要定期对绝缘油进行更换或者净化处理来保证设备工作稳定。传统的净化方法效率低下,无法清除细小颗粒和酸降解产物。为改善老化绝缘油的净化工艺,采用静电纺丝法制备了不同聚偏氟乙烯(polyvinylidene fluoride,PVDF)质量分数下表面改性微纳米复合纤维滤膜。通过对微纳米复合纤维膜的表面形貌进行表征,PVDF微纳米纤维的直径随着所配混合溶液中溶质质量分数的增加而逐渐增大。同时,纳米纤维晶体结构的α相的含量逐渐减少,β相的含量则呈现增加的趋势。表面改性的微纳米复合纤维膜具有较高的疏水性,其水分滤除率达98.8%,将老化油的击穿电压提高了50.38%,在很大程度上恢复了其绝缘性能。通过静电纺丝制备的表面改性微纳米复合纤维滤膜有效滤除了老化绝缘油中存在的水分和带电胶体,为绝缘油回收提供了一种更实用的方法。

右美托咪定联合氢吗啡酮对妊高征患者剖宫产术后硬膜外镇痛效果和循环的影响

目的:探讨右美托咪定联合盐酸氢吗啡酮对妊娠高血压综合征(妊高征)患者剖宫产术后硬膜外自控镇痛的效果和循环的影响.方法:90例择期行剖宫产术妊高征患者,随机分为3组:氢吗啡酮6 mg(H6组),右美托咪定+氢吗啡酮4 mg(H4组),吗啡4 mg(M组),每组30例.3组均采用腰麻与硬膜外联合麻醉,术后给予病人自控硬膜外镇痛(PCEA)镇痛,PCEA容量及参数设置相同.记录术前(T0)、术后4 h(T4)、8 h(T8)、12 h(T12)、24 h(T24)、36 h(T36)、48 h(T48)各时间点的平均动脉压(MAP)、心率(HR)、呼吸(R)、脉搏血氧饱和度(SpO2)、Ramsay镇静评分(RSS)、视觉模拟镇痛评分(VAS),舒适度评分(BCS)等,记录术后48 h追加补充镇痛药的种类、次数以及术后恶心、呕吐、皮肤瘙痒等不良反应的发生情况,记录血管活性药物的使用情况及患者的舒适度.结果:术后H6和H4组的MAP、HR低于M组,差异有统计学意义(P<0.05);3组的VAS评分和呼吸频率无统计学差异(P>0.05);3组患者的Ramsay评分和BCS评分从T12后组间比较差异有统计学意义(P<0.05);术后H6和H4组胃肠蠕动的恢复比M组快(P<0.05);H6组和H4组不良反应发生率低于M组(P<0.05);3组都没有追加阿片类镇痛药.结论:术后联合盐酸氢吗啡酮4 mg和右美托咪定每小时每千克0.15μg硬膜外腔泵注,能有效治疗妊高征患者剖宫产术后急性疼痛,维护循环稳定,术后不良反应少,改善了产妇产后的舒适度.

面向B5G/6G的三三三网络体系架构和优化学习机制

面对未来B5G/6G网络是大连接复杂智能网络,极其大量的用户连接、需求连接、服务连接,加之3G、4G、5G甚至6G的综合运用,将导致网络变得极其复杂的挑战,提出了一种三三三网络体系架构,它是一个包含3类网络(核心网、接入网、终端网)、3种资源(频率带宽、功耗、时延)和3项需求(生活、工作、服务)的三维立体综合优化的体系架构,简称三三三网络。进而,论证了三维立体复杂体系的数学计算式,给出了知识+数据驱动学习模型和利用知识学习机制进行智能处理的优化方法。最后,给出了三三三网络的数值例和可达性能。研究结果表明,所提三三三网络体系架构和优化方法对于设计和运行未来的大连接复杂智能网络是有益的。

Capacity-Power Consumption and Energy-Efficiency Evaluation of Green Wireless Networks

In this paper,we discuss in detail the basic issue of green design and consider an energy efficiency function as the metric to evaluate green cellular networks.Specifically,we investigate the transmit power required for an expected transmission capacity and propose a capacity-power formula based on the energy conservation and the Shannon capacity theorem.Two novel definitions of cell interference depth and handoff dynamic model are introduced and the corresponding expression of energy efficiency function is derived.Numerical results show that the energy efficiency function is closely correlated with the transmitted/received power required and the cell radius.Our work provides a useful basis for research and evaluation on green design and technology of cellular networks.

Energy Efficiency Optimization in Relay-Assisted Networks with Energy Harvesting Relay Constraints

In this paper we consider data transmission in a decode-and-forward(DF)relay-assisted network in which the relay is energy harvesting(EH) powered while the base station(BS) is power-grid powered.Our purpose is to maximize the BS's energy efficiency(EE) while making full use of the relay's renewable energy and satisfying the specific average throughput requirements.In contrast to existing literature on energy harvesting system which only considers the radio transmission power,we take the static circuit power into account as well.We formulate the EE optimization problem and prove that the EE of the BS and relay are both quasiconvex in the instantaneous transmission rate.Then we divide the complex optimization problem into two point-to-point link level optimization parts and propose an energyefficient resource allocation(EERA) scheme in which power control and sleep mode management are jointly used.The simulation results demonstrate that EERA may achieve good energy saving effects.We also compare the EE of an energy harvesting relay system with a power-grid powered one and provide more insight into the EE problem of energy harvesting relay system.

Saving Energy for Wireless Transmission:An Important Revelation from Shannon Formula

The reduction of power consumption is important for wireless communications and networks.To develop the energy-saving technologies for future wireless transmissions and networks,this paper presents two basic study points:1)The multiple events are merged into a single event;2)the high-order mode is changed to the low-order mode.For this rea⁃son,we seek that multiple events in wireless transmission links are fused into a single event from Shannon formulas.We also analyze the relationship between the information modula⁃tion and the error correction,and give a fusion structure of error-corrected modulation.The energy-saving performance of the error-corrected modulation method is further analyzed through comparison with the traditional methods of modulation plus error correction.The re⁃sults of numerical analysis demonstrate the wireless energy saving methods for wireless sys⁃tems based on Shannon formulas are the achievable efficient schemes.

Design and Optimization of Communication System Based on Superconducting Three-Energy-Level System

We propose aΛ-type superconducting three-energy-level device-based communication system for extremely weak microwave communication scenarios,for example,long-distance deep-space communication.We provide a system diagram and propose the frame synchronization and power estimation approaches based on pre-defined synchronization sequences.Based on the microwave response characteristics of the superconducting three-energy-level system,we further investigate the optimization of synchronization sequence and information symbol modulation.We show that three-energy-level systems with weak Markovianity can be approximated using independent identical distribution methods to obtain optimal synchronization sequences,and the optimal modulation is asymmetric.The proposed system design and optimization approaches are evaluated by numerical results.Moreover,we investigate the performance of the three-energy-level communication system in the presence of interference.Simulation results show that the three-energy-level communication system can tolerate more than 10 dB interference compared to long term evolution(LTE)systems and achieve the same communication rate for the same bandwidth and temperature.