面向星载海洋盐度探测应用的L波段综合孔径辐射计原理样机研制与试验研究

主被动联合微波成像仪(MICAP)是面向全球星载海洋盐度探测应用提出的一种新技术方案,由L, C, K频段辐射计及L波段散射计组成。其中L波段1维综合孔径辐射计是MICAP的核心,用以实现海洋盐度高精度观测。为了验证MICAP概念和性能,研制了一台地面原理样机并进行了试验研究。该文介绍了MICAP样机的L波段综合孔径辐射计子系统的研究与试验结果。首次推导了一种使用三阶量化均值对数字相关到模拟相关转换中的AD偏置误差进行校正的计算方法。该文的研究成果将为海洋盐度卫星MICAP及全球水循环卫星WCOM提供技术参考。     

从简、精细设计中心城区外围交叉口——以菏泽市北外环与牡丹路交叉口为例

中心城区外围的主要道路交叉口经常是交通拥堵地段,也是近年来常见的路口改造案例.本文以菏泽市北外环与牡丹路交叉口改造设计为例,详细比较不同交叉口形式的优劣,采用环形交通辅以信号灯控制的方案,试图以简易、渐进的方式,解决多路口、异形交叉口的交通问题.     

基于BIM的抗震支吊架编码体系与智能设计研究

结合国内外相关标准,对抗震支吊架进行分类与编码体系研究,补充建立了抗震支吊架编码体系。基于BIM技术建立抗震支吊架参数化构件库,通过数据驱动完成了典型构件库的数据架构。以Revit软件为平台,通过API二次开发技术,对抗震支吊架进行智能布置与编码,并实现自动生成二维码、导出物料清单等功能。     

城市暴雨强度公式拟合方法研究

为了寻求精度更高的暴雨强度公式,提出嵌入共轭梯度的自适应小生境遗传优化算法,该算法基于绝对均方差最小准则和相对均方差最小准则构建暴雨强度公式参数优化模型.通过标准遗传算法中引入小生境技术提高了种群多样性,同时与共轭梯度算法相结合增强了算法的局部搜索能力,使得遗传算法全局搜索能力强和共轭梯度法局部搜索能力强这2个优势有效结合,并应用于暴雨强度公式参数的优化计算.以北京、广州和郑州的降雨资料为基础进行暴雨强度公式优化研究,并将本文算法与传统方法和标准遗传算法进行比较.结果表明：运用本文算法对暴雨强度公式参数进行优化时,优化结果较好且能满足规范要求.与传统方法和标准遗传算法相比,优化结果具有更高的精度,为暴雨强度公式的推求提供参考依据.

     

邻近公路输电铁塔边坡定量风险评估

[目的] 为了定量计算输电线路铁塔边坡风险,采取合理手段管理铁塔边坡,保证架空输电线路安全平稳运行。 [方法] 以深圳某铁塔边坡为研究对象,根据边坡风险评估框架体系,通过边坡破坏概率分析、危险性分析和危害后果分析,结合边坡周边环境条件,定量计算由于边坡变形破坏可能造成的直接经济损失。 [结果] 通过边坡定量风险评估,即使在安全系数满足规范前提下,边坡仍然具有4.75%的破坏概率,财产损失的风险评估值为17.4万元。 [结论] 提出并例证了一套输电铁塔定量风险评估方法,评估结果可为输电线路铁塔边坡运营维护部门提供参考价值。     

Mechanical properties and microstructure evolution of KD-SA SiCf/BN/SiC CMCs oxidized at different temperatures

Silicon carbide fiber-reinforced SiC ceramic matrix composites (SiC_f/SiC CMCs) based on a domestic KD-SA SiC fiber were exposed to a wet oxygen atmosphere for 135 h at 800, 1100, and 1300°C. The evolution of the microstructure and mechanical properties of SiC_f/SiC CMCs have been systematically investigated following oxidation. For weight change, CMC-1300 showed the greatest gain (0.394%), followed by CMC-1100 (0.356%) and CMC-800 (0.149%). The volatilization of boron oxide (B₂O₃) combined with the slight oxidation of the SiC matrix at 800°C caused crack deflection and fiber pull-out. The complete dissipation of the interphase could be found when the oxidation temperature increases to 1100°C, generated a fracture surface with brittle fracture characteristics. At 1300°C, crystalline SiO₂ hindered oxygen diffusion, with evidence of fiber pull-out. Based on thermodynamic calculations and microscopic observations, we propose a mechanism to explain the thermal degradation of SiC_f/SiC CMCs. This work offers valuable guidance for the fabrication of SiC_f/SiC CMCs that are suitable for high-temperature applications.     

Wireless communication and wireless power transfer system for implantable medical device

Traditional magnetically coupled resonant wireless power transfer technology uses fixed distances between coils for research, to prevent fluctuations in the receiving voltage, and lead to reduce transmission efficiency. This paper proposes a closed-loop control wireless communication wireless power transfer system with a wearable four-coil structure to stabilize the receiving voltage fluctuation caused by changes in the displacement between the coils. Test results show that the system can provide stable receiving voltage, no matter how the distance between the transmitting coil and the receiving coil is changed. When the transmission distance is 20 mm, the power transfer efficiency of the system can reach 18.5% under the open-loop state, and the stimulus parameters such as the stimulation period and pulse width can be adjusted in real time through the personal computer terminal.     

Photo-induced doping effect and dynamic process in monolayer MoSe2

Dynamic processes of electron transfer by optical doping in monolayer MoSe₂ at 6 K are investigated via measuring time resolved photoluminescence (PL) traces under different excitation powers. Time-dependent electron transfer process can be analyzed by a power-law distribution of t^−α with α = 0.1–0.24, depending on the laser excitation power. The average electron transfer time of approximately 27.65 s is obtained in the excitation power range of 0.5 to 100 μW. As the temperature increases from 20 to 44 K, the energy difference between the neutral and charged excitons is observed to decrease.     

提取工艺对金银花叶提取物的油脂抗氧化活性的影响

以金银花叶为原料,研究了提取溶剂、提取工艺条件对金银花叶的油脂抗氧化活性的影响。以过氧化值为测定指标,筛选了最佳提取溶剂,并以油脂氧化的抑制率为测定指标,通过响应面实验对提取工艺条件进行了优化。实验结果表明:乙醇为最佳提取剂,当乙醇浓度71%、液料比31:1(m L/g)、温度75℃、时间4.5 h,提取物对玉米油的抗氧化能力最强,抑制率达到了71.9%。因此,选择合适的提取工艺,能提高金银花叶提取物对油脂的抗氧化活性。