Growth of Gallium Nitride Films on Multilayer Graphene Template Using Plasma-Enhanced Atomic Layer Deposition

In this work,the GaN thin films were directly deposited on multilayer graphene(MLG) by plasma-enhanced atomic layer deposition.The deposition was carried out at a low temperature using triethylgallium(TEGa) precursor and Ar/N_2/H_2 plasma.Chemical properties of the bulk GaN and GaN-graphene interface were analyzed using X-ray photoelectron spectroscopy.The sharp interface between GaN and graphene was verified via X-ray reflectivity and transmission electron microscope.The microstructures and the nucleation behaviors of the GaN grown on graphene have been also studied.The results of grazing incidence X-ray diffraction and Raman spectrum indicate that the as-deposited sample is polycrystalline with wurtzite structure and has a weakly tensile stress.Optical properties of the sample were investigated by photoluminescence(PL) at room temperature.The successful growth of GaN on MLG at a low temperature opens up the possibility of ameliorating the performance of electronic and optical devices based on GaN/graphene heterojunction.     

Oxidation Performance and Interdiffusion Behavior of a Pt-Modified Aluminide Coating with Pre-deposition of Ni

To refrain the interdiffusion of elements while holding good oxidation resistance,a(Ni,Pt)Al/Ni composite coating was prepared by sequential treatments of electroplating Ni and Pt and successive gaseous aluminization.In comparison with normal(Ni,Pt)Al coating,high-temperature performance of the composite coating was evaluated in isothermal oxidation test at 1100℃.Both the two coatings exhibited good resistance against high-temperature oxidation,but the interdiffusion of elements between composite coating and single-crystal(SC) superalloy substrate was greatly relieved,in which the thickness of secondary reaction zone(SRZ) and the amount of precipitated topologically close-packed phase in the SC alloy matrix were significantly decreased.Mechanisms responsible for delaying rate of coating degradation and SRZ growth/propagation are discussed.     

基于人工神经网络的核素识别方法

针对传统核素识别方法不具有强适应性导致识别率降低的问题,建立基于反向传播(back propagation,BP) 神经网络的核素识别预测模型。以镅、镉、钚、氡、钯、钴、铯7 种核素的实测信号为例进行仿真模拟,建立核素 识别模型。结果表明：该模型能快速准确地识别上述核素,应用前景广泛。     

基于MSP430 单片机的智能手枪枪-弹识别系统

为解决丢失枪、弹后给社会带来的危害及加强警方对枪、弹的管控等问题,基于MSP430 单片机与无线 射频技术(radio frequency identification,RFID)设计一套智能枪-弹识别系统。该系统包括接触式电子击发手枪弹、 枪内处理单元2 部分,可以实现枪-弹识别：正常击发编写过特殊识别码的子弹,对码失败或没有编写识别码的普通 子弹无法完成击发,并在击发失败后触发失败提醒。结果表明：该系统可以有效减少因枪支违法外流带来的生命财 产损失,加强枪、弹管控。     

地铁专用间接蒸发冷却器布水方式优化

为了解决常规间接蒸发冷却器由于表面水膜均匀性、完整性差而导致换热效率低的问题,提出了两侧旋转布水间接蒸发冷却器,进行了3种布置方式下的换热性能实验,运用正交实验对影响换热器性能的因素进行研究,研究表明:开孔正对气流方向时换热器换热性能最佳,且旋转布水装置存在最佳转速76r/min,喷水量、空气流速、冷却水流量、冷却水进口温度的增加使换热器的换热量增大,喷水温度、空气温度的升高使换热器的换热量减少,其中冷却水进口温度的改变对换热性能的影响最为显著,温度由35℃上升到39℃时,换热量提高37.62%,单位面积换热量为1.14kW,该换热器可安装于地下车站排风坑道内,可有效地解决地铁站冷却塔安装位置难题。     

Latest progress of soft rock mechanics and engineering in China

The progress of soft rock mechanics and associated technology in China is basically accompanied by the development of mining engineering and the increasing disasters of large rock deformation during construction of underground engineering.In this regard,Chinese scholars proposed various concepts and classification methods for soft rocks in terms of engineering practices.The large deformation mechanism of engineering soft rocks is to be understood through numerous experiments;and thus a coupled support theory for soft rock roadways is established,followed by the development of a new support material,i.e.the constant resistance and large deformation bolt/anchor with negative Poisson’s ratio effect,and associated control technology.Field results show that large deformation problems related to numbers of engineering cases can be well addressed with this new technology,an effective way for similar soft rock deformation control.     

供水企业产销差控制工作的策略与实践

产销差控制是国内外供水企业普遍重视的工作之一。以佛山市水业集团有限公司旗下A供水分公司2012年产销差控制的实践工作为例,对该公司产销差控制工作进行了总结与分析。分析表明,A公司产销差控制工作取得了一定成效,但仍存在一些问题需要进一步研究与探讨。     

丹江口水库水低温低浊期混凝剂优选

针对低温低浊时期丹江口水库水,通过混凝沉淀烧杯试验,对水厂普遍使用的3种混凝剂三氯化铁（FeCl3）、聚合氯化铝（PAC）和硫酸铝（AS）的投加量与沉淀时间进行优选.结果表明,在试验范围内,FeCl3和PAC投加量与余浊有很强的负相关性,在投加量为12 mg/L时余浊最小,分别为0.38和0.30 NTU,明显优于AS;混凝剂投加量与UV254去除效果高度正相关,混凝剂对UV254去除作用强弱关系为PAC＞AS＞FeCl3,投加量为12 mg/L时去除率最高,分别为59％,57％和52％;投加FeCl3和PAC所形成的絮体沉淀速度快,在20～ 30 min时即可完全沉淀,而投加AS形成的絮体所需沉淀时间在40 min以上.最后在中试系统对最优混凝剂PAC投加量与浊度和UV254之间的关系进行了适应性检验,结果表明适应性良好.     

市政道路施工中软基加固技术的应用分析

软土基处理的质量好坏既可以对市政道路路基具有的基础承载力有着直接的影响,还可以确保市政道路建设完工后的高效运行以及安全运营。反之则会导致出现地基失稳的情况,从而使道路出现不均匀沉降以及沉降过大的情况,并严重危害着市政道路。     

医院智能化安防系统的实用性

随着医院的改造和建设,对于智能化建设的需求越来越大。加之医院具有一定的特殊性,对于安防系统的建设就变得十分有必要。为了提高工作效率,减少医者和病患之间矛盾的发生,要求进行智能化的安防系统建设。