The profile of temperature and voltage dependent series resistance and the interface states in (Ni/Au)/Al0.3Ga0.7N/AlN/GaN heterostructures

The temperature dependence of capacitance-voltage (C-V) and the conductance-voltage (G/w-V) characteristics of (Ni/Au)/Al_0.3Ga_0.7N/AlN/GaN heterostructures were investigated by considering the effect of series resistance (R_s) and interface states N_ss in a wide temperature range (79-395 K). Our experimental results show that both R_s and N_ss were found to be strongly functional with temperature and bias voltage. Therefore, they affect the (C-V) and (G/w-V) characteristics. The values of capacitance give two peaks at high temperatures, and a crossing at a certain bias voltage point (∼3.5 V). The first capacitance peaks are located in the forward bias region (∼0.1 V) at a low temperature. However, from 295 K the second capacitance peaks appear and then shift towards the reverse bias region that is located at ∼−4.5 V with increasing temperature. Such behavior, as demonstrated by these anomalous peaks, can be attributed to the thermal restructuring and reordering of the interface states. The capacitance (C_m) and conductance (G/w-V) values that were measured under both reverse and forward bias were corrected for the effect of series resistance in order to obtain the real diode capacitance and conductance. The density of N_ss, depending on the temperature, was determined from the (C-V) and (G/w-V) data using the Hill-Coleman Method.     

Ionic Liquid Analogs of AlCl3 with Urea Derivatives as Electrolytes for Aluminum Batteries

The ionic liquid analog, formed through the mixture of urea and AlCl₃, has previously shown to serve as a low‐cost electrolyte for an aluminum‐graphite battery, while maintaining good performance and achieving high Coulombic efficiency. Undesirable are the relatively high viscosity and low conductivity of this electrolyte, when compared to chloroaluminate ionic liquids with organic cations. In this work, the fundamental changes to the electrolyte resulting from using derivatives of urea (N‐methyl urea and N‐ethyl urea), again mixed with AlCl₃, are examined. These electrolytes are shown to have significantly lower viscosities (η = 45, 67, and 133 cP when using N‐ethyl urea, N‐methyl urea, and urea, respectively, at 25 °C). The associated batteries exhibit higher intrinsic discharge voltages (2.04 and 2.08 V for N‐methyl urea and N‐ethyl urea electrolytes, respectively, vs 1.95 V for urea system@100 mA g^?1 specific current for ≈5 mg cm^?2 loading), due to changes in concentrations of ionic species. Aluminum deposition is directly observed to primarily occur through reduction of Al₂Cl₇^? when AlCl₃ is present in excess, in contrast to previously suggested cationic Al‐containing species, via operando Raman spectroscopy performed during cyclic voltammetry.     

有线电视双向网络设计和回传调试

较详细阐述了有线电视双向网络光节点的设置,电缆干线网、用户分配网的设计等问题,最后介绍了回传调试的有关操作事宜。     

TD-SCDMA覆盖与容量规划分析

作为中国自主研发3G标准,TD-SCDMA倍受瞩目,其优质无线网规需求亦提上日程。基于TD-SCDMA系统所赋予的技术特色,就无线网覆盖规划方面的部分关键参数如干扰余量、处理增益、智能天线赋形增益及业务Eb/N0等值的选取及相应的覆盖能力与WCDMA系统进行对比解析,同时对容量设计方法予以探讨,并以实例结果列出,其思路及结果可供实际商用网设计参考。     

基于组件对象模型的上位机—PLC串行通讯程序设计

通过应用COM技术及对三菱公司FX-2N系列PLC串行通讯协议的分析,建立了用于微机-FX-2NPLC控制器的自动化服务程序的实用模型,并且完成了和上位机用户程序的集成,通过实际的运行测试,成功地对PLC中的参数进行监控和改写。     

按N·S方程计算明渠扩展段紊流（回流）的第二次进展

继上篇文章［１］之后，我们对扩展段紊流作了进一步研讨，取涡粘性系数为５×１０－４ｍ２／秒左右时，不仅获得了标准的回流长度，而且在角点后出现了成串的小涡，接近原型真实流态，文中提出了一些计算方法问题供大家讨论。     

研讨传声器管的特定参数IDS

介绍了传声器结构原理与普通JFET的区别,说明了外加电阻器R或"两孔"的基本原理和作用,研究分析了传声器的工作电流IDS和饱和漏电流IDSS的特性以及两者之差形成的原因,并进行了大量实验。最后指出,加电阻器结构逐渐减少甚至取消,而外加"两孔"已被大量采用,更适应大批量生产需要。而IDS变化,进而又改变其他电参数,是生产传声器管中的重要问题。     

A highly luminescent organic crystal with the well-balanced charge transport property: The role of cyano-substitution in the terminal phenyl unit of distyrylbenzene

1,4-bis(2-cyano styryl)benzene (2-CSB) crystal with cyano substituent groups introduced to the terminal phenyl rings of distyrylbenzene (DSB) has been prepared and its luminescence efficiency could be as high as ∼55%. Based on the analyses of cyclic voltammetry and crystal structure, cyano substituents not only lower the LUMO level but also result in a change of the packing mode from the herringbone arrangement to the face-to-face slipped π stacking motif. Then field-effect transistors (FETs) based on high-quality 2-CSB crystals grown by the physical vapor transport method have been fabricated and the highest hole and electron mobilities were measured as 0.66 and 0.29 cm²/Vs, which enhanced the corresponding values of DSB crystal by up to one and two orders of magnitude, respectively. 2-CSB crystal simultaneously combined the high luminescence and the well-balanced mobility is expected to be of interest for the fundamental research of organic light-emitting devices.     

Smart Hybrids of Zn2GeO4 Nanoparticles and Ultrathin g‐C3N4 Layers: Synergistic Lithium Storage and Excellent Electrochemical Performance

Smart hybrids of Zn₂GeO₄ nanoparticles and ultrathin g‐C₃N₄ layers (Zn₂GeO₄/g‐C₃N₄ hybrids) are realized by a facile solution approach, where g‐C₃N₄ layers act as an effective substrate for the nucleation and subsequent in situ growth of Zn₂GeO₄ nanoparticles. A synergistic effect is demonstrated on the two building blocks of Zn₂GeO₄/g‐C₃N₄ hybrids for lithium storage: Zn₂GeO₄ nanoparticles contribute high capacity and serve as spacers to isolate the ultrathin g‐C₃N₄ layers from restacking, resulting in expanded interlayer and exposed vacancies with doubly bonded nitrogen for extra Li‐ion storage and diffusion pathway; 2D g‐C₃N₄ layers, in turn, minimize the strain of particles expansion and prevent the formation of unstable solid electrolyte interphase, leading to highly reversible lithium storage. Benefiting from the remarkable synergy, the Zn₂GeO₄/g‐C₃N₄ hybrids exhibit highly reversible capacity of 1370 mA h g^?1 at 200 mA g^?1 after 140 cycles and excellent rate capability of 950 mA h g^?1 at 2000 mA g^?1. The synergistic effect originating from the hybrids brings out excellent electrochemical performance, and thus casts new light on the development of high‐energy and high‐power anode materials.     

基于EM78P419N单片机的消毒烘干机的设计

为了改善传统烘干机烘手时间长、易交叉感染、可靠性低等问题,进行了消毒干手机的设计。该设计利用红外技术检测信号,再将光信号转换成电信号送入EM78P419N单片机,通过单片机的处理后,启动电磁阀和滴水泵进行消毒。定时完成后,启动加热器和风扇进行烘干。整个过程完全自动控制,避免了交叉感染,手伸即喷,手离即停。同时,研制出的样品具有成本低、体积小、可靠性高、干手时间短等优点,在各类人员聚集或流动的场所应用广泛。