A Cloud-Based Wireless Radio Intensity Recording System

Wireless Personal Communications - In recent years, many wireless communication services have become indispensable for our daily life, such as voice telephoning and the internet surfing. However,...     

Novel Bi-Doped Amorphous SnOx Nanoshells for Efficient Electrochemical CO2 Reduction into Formate at Low Overpotentials

Engineering novel Sn-based bimetallic materials could provide intriguing catalytic properties to boost the electrochemical CO₂ reduction. Herein, the first synthesis of homogeneous Sn_1−xBi_x alloy nanoparticles (x up to 0.20) with native Bi-doped amorphous SnO_x shells for efficient CO₂ reduction is reported. The Bi-SnO_x nanoshells boost the production of formate with high Faradaic efficiencies (>90%) over a wide potential window (−0.67 to −0.92 V vs RHE) with low overpotentials, outperforming current tin oxide catalysts. The state-of-the-art Bi-SnO_x nanoshells derived from Sn_0.80Bi_0.20 alloy nanoparticles exhibit a great partial current density of 74.6 mA cm⁻² and high Faradaic efficiency of 95.8%. The detailed electrocatalytic analyses and corresponding density functional theory calculations simultaneously reveal that the incorporation of Bi atoms into Sn species facilitates formate production by suppressing the formation of H₂ and CO.     

压水堆核电厂堆外源量程探测器计数率分析

压水堆核电厂启动过程中，次级中子源为堆外源量程探测器提供本底计数率，避免测量盲区，确保反应堆安全启动。但次级中子源的引入会为核电厂带来较大的经济和环境负担，同时也需承受次级中子源破损等带来的风险。为此，可使用受辐照燃料组件的自发裂变中子源进行替代，即无源启动方式。通过研究堆外源量程探测器计数率的理论计算方法，并基于运行电厂测量数据进行分析验证，为源量程探测器计数率的理论预估提供了较为完善的理论方法流程。本文结果可为无源启动源量程探测器计数率分析提供支持，同时也可用于次级中子源装载量或布置位置的优化分析等。     

Fabrication of Cu/graphite film/Cu sandwich composites with ultrahigh thermal conductivity for thermal management applications

Effective thermal management of electronic integrated devices with high powder density has become a serious issue, which requires materials with high thermal conductivity (TC). In order to solve the problem of weak bonding between graphite and Cu, a novel Cu/graphite film/Cu sandwich composite (Cu/GF/Cu composite) with ultrahigh TC was fabricated by electro-deposition. The micro-riveting structure was introduced to enhance the bonding strength between graphite film and deposited Cu layers by preparing a rectangular array of micro-holes on the graphite film before electro-deposition. TC and mechanical properties of the composites with different graphite volume fractions and current densities were investigated. The results showed that the TC enhancement generated by the micro-riveting structure for Cu/GF/Cu composites at low graphite content was more effective than that at high graphite content, and the strong texture orientation of deposited Cu resulted in high TC. Under the optimizing preparing condition, the highest in-plane TC reached 824.3 W·m⁻¹·K⁻¹, while the ultimate tensile strength of this composite was about four times higher than that of the graphite film.     

AutoCAD、StruCAD 3D及SolidWorks软件在石油井架、底座强度校核中的应用

分别使用AutoCAD、StruCAD 3D及Solid Works软件在石油井架、底座校核中进行强度分析,AutoCAD软件的主要优势在工程制图领域,兼具强度分析功能,适用于单个形状比较规则的型材强度分析;StruCAD 3D是专门针对大型钢结构进行强度校核的分析软件,具有强大的计算处理功能,兼具风载处理能力,在处理大型、复杂结构的时候应优先考虑应用该软件;当遇到需要进行实体造型、模拟实际情况进行校核时,SolidWorks软件较为方便,可以直观地看到应变情况。     

车用复合材料板簧性能的有限元分析

为了初步验证所设计复合材料板簧的结构性能,利用有限元分析方法对复合材料板簧结构的静载力学和动态疲劳进行了研究。计算得到空载工况加载过程中的载荷—位移曲线,板簧刚度为373 N/mm。当两端施加载荷为64.7 kN时,板簧达到最大压缩应力。结合复合材料的S—N曲线对板簧寿命进行了估算,循环次数最低处位于板簧下表面靠近卷耳部分,循环次数为33万次。对比复合材料板簧的设计刚度和疲劳寿命,与有限元分析处理方法计算所得结果较为接近,该板簧结构基本符合使用要求。     

黏性土和纤维对风积沙改性土热膨胀特性的影响

风积沙改性土的热膨胀特性对评价风积沙改性土路基温度稳定性至关重要.通过在风积沙中掺入不同质量的水泥、黏性土或聚丙烯纤维制成不同配比的改性土,测试改性土的热膨胀系数,研究外加材料的掺入量对改性土热膨胀特性的影响.试验结果表明:改性土的平均线膨胀系数随着水泥掺入量的增加总体呈增大趋势,随着聚丙烯纤维掺入量的增加而减小,随着黏性土掺入量的增加而增大.聚丙烯纤维的掺入可有效降低改性土的热膨胀系数.研究成果可为进一步优化改性土提供研究方向,为高温差沙漠地区工程建设中风积沙改性土温度裂缝的控制提供试验依据.     

聚酯类增塑剂的合成与应用研究进展

综述了国内外聚酯增塑剂的合成及应用的最新研究进展，重点介绍了超支化、生物基、石油基聚酯增塑剂的合成与制备方法以及不同类型聚酯增塑剂在聚氯乙烯(PVC)、淀粉、聚乳酸、聚氨酯弹性体与橡胶制品中的最新应用研究进展；并对聚酯增塑剂未来发展方向做了展望。     

刮板输送机中板仿生耐磨优化试验研究

刮板输送机中板磨损失效已成为输送机运行故障的主要原因之一，为了提高中板耐磨性，基于蜣螂非光滑单元进行了仿生中板设计，以磨损量为响应值，进行了单因素和响应面法优化试验。根据响应面法试验结果得到的因素显著性影响顺序（从高至低）依次为：径向距离，深径比，直径，节距角。基于试验结果建立了磨损量与因素的回归预测模型，经试验对比发现，预测模型与真实试验的相对误差为3.2%。在特定工况（煤散料粒度为6~8 mm、载荷为20 N、刮板链速为0.65 m/s及试验时长为6 600 s）下，当深径比为1.41、直径为0.69 mm、节距角为6.55°和径向距离为4.66 mm时，磨损量最小，仿生中板的耐磨性提高了12.6%。分析其耐磨机理发现，与光滑板相比，仿生板的磨粒磨损及黏着磨损较轻。凹坑分布可破坏持续切削中板表面的煤粒运动状态。中板的仿生优化可为今后刮板输送机的设计提供一定参考。     

新型钢丝圈清洁器的使用效果

为了解决钢丝圈挂花问题,阐述了LH001新型钢丝圈清洁器的特点和应用效果;通过试验说明使用新型钢丝圈清洁器断头率低,基本无挂花,纺纱效果好。指出:新型钢丝圈清洁器是普通钢丝圈清洁器的更新换代产品,值得推广。