Surface Oxygen Coordination of Hydrogen Bond Chemistry for Aqueous Ammonium Ion Hybrid Supercapacitor

Aqueous ammonium ion hybrid supercapacitor (A-HSC) combines the charge storage mechanisms of surface adsorption and bulk intercalation, making it a low-cost, safe, and sustainable energy storage candidate. However, its development is hindered by the low capacity and unclear charge storage fundamentals. Here, the strategy of phosphate ion-assisted surface functionalization is used to increase the ammonium ion storage capacity of an α-MoO₃ electrode. Moreover, the understanding of charge storage mechanisms via structural characterization, electrochemical analysis, and theoretical calculation is advanced. It is shown that NH₄⁺ intercalation into layered α-MoO₃ is not dominant in the A-HSC system; rather, the charge storage mainly depends on the adsorption energy of surface “O” to NH₄⁺. It is further revealed that the hydrogen bond chemistry of the coordination between “O” of surface phosphate ion and NH₄⁺ is the reason for the capacity increase of MoO₃. This study not only advances the basic understanding of rechargeable aqueous A-HSC but also demonstrates the promising future of surface engineering strategies for energy storage devices.     

Efficient electron transport in 4,4′-bis[N-(1-napthyl)-N-phenyl-amino] biphenyl and the applications in white organic light emitting devices

The electron transport capability of 4,4′-bis[N-(1-napthyl)-N-phenyl-amino] biphenyl (α-NPD) was investigated by fundamental physical measurements named as current–voltage (I–V) electrical property evaluation and displacement current measurement (DCM). In electron-dominated devices, the I–V characteristics of α-NPD were similar as that of (8-hydroxyquinolino) aluminum (Alq₃) owing to their same order of electron mobilities. The interface of Al/LiF and α-NPD was proven to be an Ohmic contact through the evaluation of I–V characteristics at low bias regime (<3 V). And an electron injection barrier, 0.21 eV, at Al/LiF/α-NPD was obtained by extrapolating the temperature dependent I–V curves. The electron transport behavior in α-NPD film was further confirmed by DCM evaluations. Furthermore, an efficient white organic light emission device was successfully fabricated by using α-NPD as hole transport layer and electron transport layer, respectively.     

超声行波微流体驱动模型的耦合分析

介绍了带有微沟道的超声行波微流体驱动的圆环模型。在对模型结构部分进行模态分析和瞬态动力学分析的基础上,基于有限元分析,针对耦合模型作声固耦合分析,分别得到与空气和水耦合时模型的固有频率;进行耦合场的流固耦合分析,采用瞬态动力学方法,得到沟道内流体在超声行波激励下的流场情况。比较不同时间子步时流体域和固体域的位移云图,得到流体随固体振动情况;分析不同时间子步时流体域的速度矢量图,得到流体在超声行波方向上的流动情况,验证了超声行波微流体驱动的可行性。     

用于宽带偏振无关耦合器的双芯光子晶体光纤

提出一种可用于宽带偏振无关光定向耦合器的新型双芯光子晶体光纤(PCF),利用全矢量有限元方法分析了光纤结构参数对其光学特性的影响,得到了一组优化的双芯PCF结构参数,满足易于制作、易于接续和接续损耗低等应用要求,在此基础上对光纤结构进行了改进,进一步降低了制作难度,基于该光纤可以设计出在1.26～1.625μm范围内分光比误差小于1%、两偏振态分光比误差小于0.2%的50:50耦合器,并在现有实验条件下,试制了近似结构的双芯PCF。     

中国联通信息化云计算工作探讨

在云计算时代,运营商需要将自身网络智能和控制能力与云服务有机结合,提出集成、高效、可靠的云平台信息化发展战略。文章以中国联通云平台试验工作为依托,分析目前运营商信息化云计算发展思路和标准化工作,并根据实际情况介绍桌面云和绿色数据中心的建设情况,为电信级的云服务运营提供参考依据。     

Effect of fluorinated silicate glass passivation layer on electrical characteristics and dielectric reliabilities for the HfO2/SiON gate stacked nMOSFET

The superior characteristics of the fluorinated hafnium oxide/oxynitride (HfO₂/SiON) gate dielectric are investigated comprehensively. Fluorine is incorporated into the gate dielectric through fluorinated silicate glass (FSG) passivation layer to form fluorinated HfO₂/SiON dielectric. Fluorine incorporation has been proven to eliminate both bulk and interface trap densities due to Hf-F and Si-F bonds formation, which can strongly reduce trap generation as well as trap-assisted tunneling during subsequently constant voltage stress, and results in improved electrical characteristics and dielectric reliabilities. The results clearly indicate that the fluorinated HfO₂/SiON gate dielectric using FSG passivation layer becomes a feasible technology for future ultrathin gate dielectrics applications.     

On reducing broadcast redundancy in ad hoc wireless networks

Unlike in a wired network, a packet transmitted by a node in an ad hoc wireless network can reach all neighbors. Therefore, the total number of transmissions (forward nodes) is generally used as the cost criterion for broadcasting. The problem of finding the minimum number of forward nodes is NP-complete. Among various approximation approaches, dominant pruning (Lim and Kim 2001) utilizes 2-hop neighborhood information to reduce redundant transmissions. In this paper, we analyze some deficiencies of the dominant pruning algorithm and propose two better approximation algorithms: total dominant pruning and partial dominant pruning. Both algorithms utilize 2-hop neighborhood information more effectively to reduce redundant transmissions. Simulation results of applying these two algorithms show performance improvements compared with the original dominant pruning. In addition, two termination criteria are discussed and compared through simulation under both the static and dynamic environments.     

高铁规划要点及测试情况分析

从理论分析、实地测试2个方面同时入手,针对郑西高铁测试过程中发现的问题提出了解决思路和实施方案,并给出了高铁规划中的一些技术要点.     

基于分数频率合成器的多标准I/Q载波产生系统

本文基于sigma-delta分数频率合成器设计了多标准I/Q正交载波产生系统。通过合理的频率规划,此系统能够应用于多标准无线通讯系统。设计采用了0.13um的标准CMOS射频工艺。测试结果显示3个正交VCO的频率覆盖范围为3.1GHz至6.1GHz(65.2%),然后通过串联的除二分频器,可以使系统的频率连续覆盖0.75GHz至6GHz。整个芯片的面积是2.1mm1.8mm。在1.2V的电源电压下系统功耗为21.7mA(除去输出缓冲级)。利用频率预置技术,锁相环的锁定时间小于4us。并且在系统中加入了非易失性存储器(NVM),能够存储系统的一些数字配置信息包括锁相环的预置信息,利用NVM的非易失存储特性,使得整个系统能够避免重复的校正。