基于蓝牙技术的电能表无线检定技术研究

传统的电能表检定通常采用人工接线方式,该方式效率低下,操作不当会导致器件损坏,存在安全隐患。为实现高效、可靠地批量电能表误差检定,文中利用低功耗蓝牙技术实现电能表的无线检定。摒弃蓝牙普通模式,采用蓝牙特殊模式,将蓝牙模块从协议层转发信号,改为从底层寄存器直接转发,极大提高了信号转发的稳定性,经多次测试,稳定性可以达到1μs以下,可以满足现在所有准确度等级电能表的检定要求。在检测时,无需将检表台体上的光电头与待检电能表的光脉冲接口和电脉冲接口相连接,减少人工参与,提高了批量电能表的误差检验效率。文中设计的基于蓝牙技术的无线光电脉冲校测系统适用于具有无线发送模块的待检电能表检测。     

放射性核素扫描计算机图像处理系统

本文介绍在IBM-PC微机上发展的一套用于核素扫描图像的处理系统。该系统具有二维快速傅立叶变换能力,可进行二十余种图像增强和复原处理,经模型实验和临床应用表明,它大大改善了图像的质量。本文介绍了系统的实现方法、处理结果和主要特点。     

30CrMnSiNi2A超高强钢HAZ后热韧化抗裂机理的探讨

本文用插销法研究了预热和后热对30CrMn SiNi2A 超高强钢HAZ 冷裂倾向和强韧性的影响规律。试验结果表明,250℃预热.260℃后热1h,插销临界启裂应力σ_(cr)>σ_s。用焊接热模拟试件测试了不同焊接热循环下的断裂韧性K_(IC),发现最优焊接热循环和插销试验时的最佳工艺相吻合。用透射电镜观察了HAZ 组织的精细结构,观察了残余奥氏体的分布形态,并测定了残余奥氏体的含量。发现250℃预热,260℃后热1h。可得到含9.8%残余奥氏体的、以位错板条马氏体为主带有少量下贝氏体的显微组织。残余奥氏体以薄膜状的形态分布于马氏体板条间,它既韧化了组织又阻碍了氢的扩散,对防止冷裂纹的产生是有益的。试验结果为后热工艺的制定和解释后热韧化抗裂的本质提供了理论依据。     

Mechanistic study on carboxymethyl hydroxyethyl cellulose as fluid loss control additive in oil well cement

The working mechanism of carboxymethyl hydroxyethyl cellulose (CMHEC, M_w 2.6 × 10⁵ g/mol) as fluid loss control additive (FLA) for oil well cement was investigated. First, characteristic properties of CMHEC such as anionic charge amount, intrinsic viscosity in cement pore solution, and static filtration properties of cement slurries containing CMHEC were determined at 27°C and 70 bar. Effectiveness of the FLA was found to rely on reduction of cement filter cake permeability. Consequently, the working mechanism is ascribed to constriction of cement filter cake pores. Zeta potential measurements confirm that at low CMHEC dosages (0–0.3% by weight of cement, bwoc), adsorption of the polymer onto the surface of hydrating cement occurs. However, at dosages of 0.4% bwoc and higher, an associated polymer network is formed. This was evidenced by a strong increase in hydrodynamic diameter of solved CMHEC molecules, an exponential increase in viscosity and a noticeable reduction of surface tension. Thus, the working mechanism of CMHEC changes with dosage. At low dosages, adsorption presents the predominant mode of action, whereas above a threshold concentration of ～ 10 g/L (the “overlapping concentration”), formation of associated polymer networks is responsible for effectiveness of CMHEC. Addition of anionic polyelectrolytes (e.g., sulfonated melamine formaldehyde polycondensate, M_w 2.0 × 10⁵ g/mol) to cement slurries containing CMHEC greatly improves fluid loss control. Apparently, the presence of such polyelectrolytes causes the formation of colloidal associates from CMHEC to occur at lower dosages. Through this mechanism, effectiveness of CMHEC as cement fluid loss additive is enhanced. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

激光喷丸强化CoCrAlY防护涂层 抗高温氧化性能研究

利用大气等离子喷涂(Air Plasma Spraying,APS)技术在镍基高温合金表面制备CoCrAlY涂层,在此基础上采用电子束真空蒸镀(Electric Beam Vacuum Deposition,EBVD)技术在涂层表面进一步沉积铝膜,以提高涂层表面Al元素含量。采用激光喷丸(Laser Peening,LP)技术分别对以上两种涂层进行强化处理。采用X射线衍射(X-Ray Diffraction,XRD)和扫描电子显微镜(Scanning Election Microscope,SEM)对比分析LP冲击前后CoCrAlY涂层表面相结构、微观形貌及成分变化。微观结构分析表明,LP处理后APS-CoCrAlY涂层表面粗糙度降低,组织致密性增加;镀铝CoCrAlY涂层经LP处理后,表面Al含量明显增加,β-CoAl相含量提高,且涂层表面晶粒得到细化。1050 ℃抗高温氧化实验结果表明,LP处理涂层表面形成的氧化膜较原始涂层更加平整、致密,且氧化膜厚度明显变薄;此外,镀铝CoCrAlY涂层经LP处理后的抗高温氧化性能最优。     

氢化钛-石墨制备Al-Ti-C母合金机理与组织性能研究

采用扫描电子显微镜（SEM）、能谱仪（EDS）、X射线衍射（XRD）等研究了由氢化钛-石墨法制备的Al-Ti-C母合金的组织性能。结果表明：由氢化钛-石墨与铝液反应制备Al-Ti-C母合金的机理是由氢化钛、石墨分别作为钛源、碳源,氢化钛受热分解为钛和氢,钛与铝、石墨反应生成钛铝、钛碳或者铝碳化合物。由铝钛化合物、碳铝化合物、钛碳化合物组成具有细化作用的Al-Ti-C母合金。合金的物相组成包括：α（Al）、铝钛、碳铝、钛碳化合物等物相,金相为等轴晶或者树枝晶组织,平均晶粒尺寸20～40μm。合金基体中存在针状、棒状的初晶相,晶界上存在含钛、碳、铁、硅的花瓣状初晶,钛、碳组元沿晶界、晶内分布大体均匀,在初晶相附近存在明显的钛、碳富集、偏聚现象。冰晶石有利于碳与铝润湿、反应,生成的第二相在晶内扩散更充分、分布也更均匀。     

基于一维卷积神经网络与改进D-S证据理论的警务云安全数据融合技术

针对系统内评估信息来源单一、准确度偏差过大与异构数据提取融合不充分的问题,提出了一种可扩展攻击行为的多源异构网络安全数据融合框架。首先,建立以攻击模式为核心的安全事件分析模型,进一步精简安全数据;其次,针对决策层数据特征提取不足的问题,建立了基于攻击行为的1D-CNN （1D convolutional neural network,1D-CNN）模型,对警务安全数据进行特征学习和重构;为了进一步提高警务云安全数据的分类能力,模型改进了D-S证据理论并结合多源安全数据的可信度进行数据融合。实验分析表明,基于1D-CNN的改进D-S证据理论模型进一步提高了警务云中安全事件的报警识别率,与其他相关技术相比,该模型具有较好的分析能力,对警务云的安全入侵检测和漏洞分析具有重要意义。     

5G路测数据智能分析策略研究

5G网络大规模建网阶段，路测作为发现及解决网络问题的主要途径之一，数据分析依赖优化工程师通过人工回放路测数据进行问题定界，准确性受工程师技能影响，而且效率低下。本文针对现阶段5G路测数据分析存在的问题，提出了基于5G路测数据的智能分析方案。本方案通过将路测常见网络问题建立算法模型，云化功能模块，实现路测数据自动化、智能化分析。     

基于安卓平台的智能定位追踪系统研究

针对目前社会上普遍关注的老人儿童安全监护问题,设计了一套基于安卓平台的智能定位追踪系统,定位移动终端获取地理位置信息并传输,安卓智能终端实现了实时监控人员位置的功能.系统经过实际应用测试,具有易携带、易操作、低功耗、低成本的特点,可广泛应用于智能定位追踪及其他相关位置服务行业.     

Working mechanism of methyl hydroxyethyl cellulose (MHEC) as water retention agent

The working mechanism of methyl hydroxyethyl cellulose, MHEC (M_w = 2.5 · 10⁵ g/mol, DS_methyl = 1.81, MS_hydroxyethyl = 0.15) as water retention agent in cement was investigated. First, the hydrocolloid was characterized and its performance as non-ionic water retention agent was determined employing the filter paper test. Also, water sorption and swelling of individual MHEC fibers under conditions of different humidities were monitored by ESEM imaging. Second, its working mechanism was established. It was found that at low dosages, MHEC achieves water retention by intramolecular sorption of water and concomitant swelling while at higher dosages, MHEC molecules agglomerate into large hydrocolloidal microgel particles (d > 1 μm) which effectively plug the pores in the mortar matrix. MHEC association was evidenced by an exponential increase in solution viscosity as concentration rises, a strong increase in the hydrodynamic diameter of solved MHEC molecules, and a noticeable reduction of surface tension.