摘要：Ceramic-reinforced metal matrix composites(MMCs)display beneficial properties owing to their combination of ceramic and metal ***,the properties are highly dependent on the reinforcing phase composition,volume fraction and *** fiber or network reinforcement morphologies are difficult and expensive to manufacture,and the often-used discontinuous particle or whisker reinforcement morphologies result in less effective ***,we demonstrate the formation of a co-continuous ceramic-reinforced metal matrix composite using solid-state *** jet additive manufacturing(BJAM)was used to print a nickel superalloy part followed by post-processing via reactive sintering to form a continuous carbide reinforcing phase at the particle *** kinetics of reinforcement formation are investigated in order to develop a relationship between reactive sintering time,temperature and powder composition on the reinforcing phase thickness and volume *** evaluate performance,the wear resistance of the reinforced BJAM alloy 625 MMC was compared to unreinforced BJAM alloy 625,demonstrating a 64%decrease in the specific wear rate under abrasive wear conditions.

摘要：Here, we report a study of ion transport across graphene oxide （GO） membranes of various thicknesses, made by vacuum filtration of GO aqueous solutions. The diffusive transport rates of two charge-equivalent ruthenium complex ions Ru（bpy）3^2＋ and Ru（phen）32% with a sub-angstrom size difference, are distinguishable through GO membranes and their ratio can be a unique tool for probing the transport-relevant pore structures. Pore and slit-dominant hindered diffusion models are presented and correlated to experimental results. Our analysis suggests that ion transport is mostly facilitated by large pores （larger than 1.75 nm in diameter） in the relatively thin GO membranes, while slits formed by GO stacking （less than 1.42 nm in width） become dominant only in thick membranes. By grafting PEG molecules to the lateral plane of GO sheets, membranes with enlarged interlayer spacing were engineered, which showed drastically increased ion transport rates and lower distinction among the two ruthenium complex ions, consistent with the prediction by the slit-dominant steric hindered diffusion model.

摘要：边际效应递减法则是经济学基本理论,在管理、环境、教育等很多领域都实证了该法则的存在性.文中通过实验验证视觉感知中是否存在边际效应递减现象.首先选取随机生成的散点图作为实验数据,选取散点图相关性作为感知对象,招募参与者并设计了实验流程;然后让参与者根据视觉感知估计散点图相关系数大小,并记录参与者在多次测试中的感知偏差和完成时间等量化指标;最后用基数效应理论计算散点图相关性视觉感知偏差的总效应曲线和边际效应曲线,并选取边际效应作为评价指标.实验结果表明,参与者在实验中出现了边际效应递减现象,即随着测试次数的增加,参与者相关性视觉感知偏差的减小幅度呈现降低趋势;同时,参与者容易低估相关性,有可视化专业知识的参与者和其他参与者在感知偏差与完成时间上不存在显著性差异.

摘要：为研究硝酸根对颗粒状铁降解三氯乙烯的影响,进行了柱实验和相应的反应铁腐蚀电位测定。在硝酸根离子存在条件下,铁的腐蚀电位相应升高,系统条件也因之发生变化,导致钝性的铁氧化物在铁表面生成。因而,三氯乙烯和硝酸根离子降解速率明显减小, 并且降解速率减小的程度与硝酸根离子的浓度成比例。当污染液流过反应柱时,硝酸根离子与铁反应, 被还原为氨根离子。该反应造成硝酸根离子的浓度梯度,使钝化区在柱中上移,从而影响了三氯乙烯的降解曲线。与三氯乙烯单独与铁反应相比,当含4 7 mg/L硝酸根的三氯乙烯溶液流经反应柱170 孔隙体积后,降解50% 三氯乙烯所需的时间(t50) 从小于4 h增加到大于10 h;而当三氯乙烯溶液中加入100 mg/L硝酸根离子,仅17 孔隙体积溶液流经反应柱后,三氯乙烯降解t50就已大于14 h。研究结果表明,由于硝酸根离子对铁的腐蚀电位和铁表面氧化膜的不利作用,在处理靶污染物为高浓度硝酸根离子和三氯乙烯共同污染的地下水时,铁渗透反应隔栅不是最佳选择。如果靶污染物中硝酸根离子浓度比较低,则在设计铁隔栅时应考虑到硝酸根离子造成的不利因素,相应增加铁墙的厚度,从而确保三氯乙烯的降解效果。

摘要：目的了解中国城市烟草广告、促销现状以及相关因素。方法在北京、上海、沈阳、长沙、广州和银川6个城市，采用累计概率比例抽样和简单随机抽样方法，对4815名18岁以上的吸烟者进行问卷调查。结果烟草广告覆盖吸烟人群最广的2种途径分别为广告牌（35．6％）、电视（34．4％）。商家最爱使用的促销手段是赠送礼品（23．1％），其次为赠送香烟（13．9％）。长沙市的吸烟者通过广告牌（Х^2=562．474，P〈0．001）以及电视（Х^2=265．570，P〈0．001）途径获取烟草广告的比例较高。长沙市吸烟者巾可看到烟草相关新闻的比例较高（Х^2=58．314，P〈0．001）。多因素logistic回归分析结果显示，生活所在城市及学历情况与“使想吸烟事物”的关注度有关。结论中国城市烟草制品广告及促销活动较为普遍，各地控烟法律法规执行效果不一，尽快完善并统一相关立法势在必行。

摘要：Interfacial space charge storage between ionic and electronic conductor is a promising scheme to further improve energy and power density of alkali metal ion batteries(AMIBs).However,the general behavior of space charge storage in AMIBs has been less investigated experimentally,mostly due to the complicated electrochemical behavior and lack of proper characterization ***,we use operando magnetometry to verify that in FeSe_(2)AMIBs,abundant Li^(+)/Na^(+)/K^(+)(M^(+))can be stored at M_(2)Se phase while electrons accumulate at Fe nanoparticles,forming interfacial space charge *** and dynamics tests further demonstrate that with increasing ionic radius from Li^(+),Na^(+)to K^(+),the reaction kinetics can be hindered,resulting in limited Fe formation and reduced space charge storage *** work lays solid foundation for studying the complex interfacial effect in electrochemical processes and designing advanced energy storage devices with substantial capacity and considerable power density.

摘要：针对现有信息系统在空间智能评价方面的薄弱之处,运用WebGIS空间智能集成方法探讨旅游景区空间智能评价系统的设计和实现,从三方面提高了旅游景区评价系统的智能化层次:通过集成旅游景区网上调查问卷系统,提高了数据收集提取的智能化层次;通过集成旅游景区模糊综合评价模型、客流结构评价模型及旅游专家知识系统,增强了评价系统的半结构化智能推理功能;采用B/S+C/S系统构架,并利用Web技术提高了人机交互界面的智能化。周庄景区案例评价结果显示,该系统原型的运行效果良好且智能化层次较高。

摘要：本文提出了一种新的基于无线信道直接加密的物理层安全通信技术。不同于传统的基于物理信道的密钥生成技术通常向合法通信双方将无线信道量化,再进行密钥协商,从而在合法通信双方生成两个完全相同的比特串作为上层密码算法加密的密钥。本文的方案中通过提取合法双方的无线信道特征的量化后的比特,通过设计的轻量级加解密算法直接对物理层比特进行加密。相比传统方案,本方案避免了物理层密钥分发的密钥协商过程,大大提升了密钥生成速率。其基本原理是合法通信双方在物理层直接用不同的密钥直接对已编码比特信息加密,而合法接收方仍然可以通过信道译码得到较低的误码率从而恢复信源比特信息,而非法窃听者由于密钥比特和合法通信双方不一致而无法解密。通过实验验证,验证了在信息传输过程中信道差错率低于5*10^-2情况下,该模型能够在保证窃听者无法解密的同时能够实现合法通信者以平均正确率99.6%接收。此外,通过修改编码的参数,本文找到了不同信噪比下最为合适的传输效率。本文的方案可在对物理层信号进行安全增强的同时兼容上层安全加解密算法,具有广泛的应用前景。