摘要：Alloying Pt with transition metals can significantly improve the catalytic properties for the oxygen reduction reaction(ORR).However,the application of Pt-transition metal alloys in fuel cells is largely limited by poor long-term durability because transition metals can easily *** this study,we developed a nonmetallic doping approach and prepared a P-doped Pt catalyst with excellent durability for the ***-supported core-shell nanoparticles with a P-doped Pt core and Pt shell(denoted as PtPx@Pt/C)were synthesized via heat-treatment phosphorization of commercial Pt/C,followed by acid *** analysis using electron energy loss spectroscopy and X-ray photoelectron spectroscopy clearly demonstrated that Pt was enriched in the near-surface region(approximately 1 nm)of the carbon-supported core-shell *** to P doping,the ORR specific activity and mass activity of the PtP_(1.4)@Pt/C catalyst were as high as 0.62 mA cm^(–2)and 0.31 mAμgPt–^(1),respectively,at 0.90 V,and they were enhanced by 2.8 and 2.1 times,respectively,in comparison with the Pt/C *** importantly,PtP_(1.4)@Pt/C exhibited superior stability with negligible mass activity loss(6%after 30000 potential cycles and 25%after 90000 potential cycles),while Pt/C lost 46%mass activity after 30000 potential *** high ORR activity and durability were mainly attributed to the core-shell nanostructure,the electronic structure effect,and the resistance of Pt nanoparticles against aggregation,which originated from the enhanced ability of the PtP_(1.4)@Pt to anchor to the carbon *** study provides a new approach for constructing nonmetal-doped Pt-based catalysts with excellent activity and durability for the ORR.

摘要：利用WRF中尺度数值模式,选取了2011年三峡水库蓄水高水位期和2022年三峡地区高温伏旱低水位汛期两个典型气候年份的不同蓄水时段,通过改变水位高度设计了两组数值试验,探究了三峡水库动态运行的水位高度变化对库区气候的影响情况。结果表明:1)三峡水库蓄水运行后,模式模拟的库区气候要素均有一定程度的改变,无论是在低水位的汛期还是高水位的蓄水期,水库蓄水水体加宽和水位抬升对气温、风、相对湿度和降水等要素均产生了局地性的影响,但不同水位高度产生的影响范围和幅度不同。2)气温在水体附近表现为降低特征、相对湿度和风速表现出增大特征,要素的变化范围主要集中在水体附近,水库蓄水对距离水域远地方的相应气象要素基本无影响。3)降水事件变化较为复杂,库区范围内的降水以略有增加为主,但在汛期时段引起库区降水的因素复杂,地形地貌、空气层结和水汽大小均会对山区降水产生重要影响。

摘要：人体穴位识别和定位是按摩机器人的关键问题,是保证机器人安全工作的先决条件。这里结合人工标志点和深度学习目标检测技术,提出了一种按摩机器人穴位贴识别和定位方法。首先在人体背部预按摩穴位点处布置圆形人工标志点,采用基于YOLOv5深度学习网络模型检测圆形标志点在图像中大致区域,并用高斯滤波法滤除该区域中的孤立点和噪声点,然后根据圆形目标的粗定位信息、图像的边缘灰度分布特征获取圆形标志点的边缘信息并检出其中最大连通区域的边缘,最后通过基于椭圆方程的最小二乘算法精确定位出人工标志点的圆心坐标,并利用机器人手眼标定技术转换为机器人按摩穴位坐标,实现人体穴位的自动识别和定位。实验结果表明,在仿真环境下圆心定位误差小于0.7像素(pixel);在实测环境下圆心定位相对误差小于1.8%,可以有效减少目标边缘模糊、相似物干扰、圆形畸变等情况对穴位贴圆心定位精度的影响。

摘要：为了跟踪国内外海上水面自主船舶(MASS)发展进程,深化对MASS自主性的理解,对国内外MASS在标准规范及科研项目上的发展进行梳理;通过绘制时间尺度上的人机运行机制图对MASS自主性进行解析并以航行感知系统为例进行实例化解读;对MASS的风险评估、模型基础、试验实践内容进行展望。总结分析目前MASS现状和主要问题,提出MASS的3种自主运行模式,为MASS的详细设计及未来发展提供依据和思路。

摘要：为实现超设计使用年限或发生严重损伤的斜拉索安全高效更换，提出了一种利用既有斜拉索锚垫板为反力系统的外置钢锚筒换索系统，设计制作了典型主梁节段缩尺模型及临时索系统全尺模型，开展了外置钢锚筒-锚垫板干接触、胶接条件下的单向轴压和偏心受压静力试验。结果表明，干接触条件下钢锚筒失效模式为偏心受压侧顶端与锚垫板接触处屈曲，灌注环氧树脂胶接触条件下其失效模式为偏心受压侧环氧树脂胶界面处屈曲。相同荷载工况下灌注胶后的钢锚筒位移及最大压应力较小，钢锚筒的受压安全性和稳定性较好。该型辅助构件可用于斜拉桥换索施工中。

摘要：为提高锻态Ti_(2)AlNb基合金后续热变形能力,对多向锻造后的Ti_(2)AlNb基合金进行了固溶+时效的热处理。研究分析了热处理前后的组织演变、力学性能以及O相的析出行为。结果表明:多向锻造后的空冷的Ti_(2)AlNb合金,组织内析出大量针状O相,位错密度高,晶粒尺寸大,导致其伸长率较低。经过热处理后形成了B2基体+双尺板条/针状O相组织,位错密度降低,α_(2)相以包析反应生成了rim-O相;晶粒内部的析出O相包含4种变体。O相在小角度晶界处沿两侧生长分布,而在大角度晶界处只沿单侧析出生长。热处理后的Ti_(2)AlNb合金表现出显著提高的伸长率,增加了后续热变形的稳定性。

摘要：In order to analyze the lubricating characteristics at different meshing points in the cycloid pin wheel transmission process,the cycloid gear teeth were discretized,combined with the kinematic analysis of the cycloid pin gear transmission and the contact analysis of the gear *** progressive mesh densification method(PMD)was used to numerically solve the film *** influence of the design parameters and process parameters on the lubrication characteristics was *** elastohydrodynamic lubrication and mixed lubrication characteristics at different contact points were *** optimal meshing area of the cycloid gear tooth was determined,and the film thickness ratio,contact load ratio,maximum contact pressure at different points,average film thickness and roughness after contact deformation were *** conclusion of this study provides effective guidance for the research on the modification of cycloid gear teeth.

摘要：膨胀珍珠岩颗粒与有机胶合体系复配改性后,经过模压静置加压、保压脱模、热反应固化成型得到有机胶合阻燃热固复合保温板。研究了膨胀珍珠岩颗粒密度、模压比以及用胶量对热固复合保温板力学性能和导热性能的影响,并进行微观分析。结果表明:复配改性阻燃胶合体系能够有效胶结膨胀珍珠岩颗粒,制备的热固复合保温板密度低,抗压强度可达0.31 MPa,导热系数仅为0.054 W/(m·K),且具备A级不燃性能,应用于建筑外墙外保温前景可观。

摘要：Carbon supported Pt-based intermetallic compounds(IMCs)with high activity and durability are the most competitive cathode catalysts for the commercialization of proton exchange membrane fuel cells(PEMFCs).The synthesis of Pt-based intermetallics with a good balance between small size and high metal loading remains challenging because of the high-temperature annealing that is generally required to form intermetallic *** developed a sodium thiosulfate-assisted impregnation strategy to synthesize small-sized and highly ordered PtM IMCs catalysts(M=Co,Fe,Ni)with high-Pt-content(up to 44.5 wt%).During the impregnation process,thiosulfate could reduce H_(2)PtCl6 to form uniformly dispersed Pt colloid on carbon supports,which in turn prevents the aggregation of Pt at the low-temperature annealing ***,the strong interaction between Pt and S inhibits particle sintering,ensuring the formation of small-sized and uniform PtM intermetallic catalysts at the high-temperature annealing *** optimized intermetallic PtCo catalyst delivered a high mass activity of 0.72 A mgPt^(–1)and a large power performance of 1.17 W·cm^(–2)at 0.65 V under H_(2)-air conditions,along with 74%mass activity retention after the accelerated stress test.

摘要：Design intelligence is an important branch of artificial intelligence(AI),focusing on the intelligent models and algorithms in creativity and *** the context of AI 2.0,studies on design intelligence have developed *** summarize mainly the current emerging framework of design intelligence and review the state-of-the-art techniques of related topics,including user needs analysis,ideation,content generation,and design ***,the models and methods of intelligence-generated content are reviewed in ***,we discuss some open problems and challenges for future research in design intelligence.