直升机传动系统试车台测控系统设计

按照GJB2035-95《直升机传动系统通用规范》的要求,直升机传动系统的研制,需要大量试车台对其设计合理性进行试验验证;通过对传统试车台测控系统建设经验的总结,在满足传动系统试车台技术指标的基础上,基于模块化设计思想,采用分布式结构和C/S模式测控网络,开发一种具有通用性的测控系统,使其满足不同规模结构、测试类型和试验方法的试车台建设任务;阐述了测控系统的结构和工作原理,详细介绍了现场设备层、数据服务器层及客户层的通讯流程和程序实现方法;该系统在满足实时性、可靠性的基础上提高了试验效率和测控精度,减少了试车台建设和适应性改造的周期和难度,增强试车台的灵活性和可维护性;系统已成功应用于多个传动系统试车台,且运行稳定可靠。     

Sentinel-1 based Soil Moisture Estimation in Middle Reaches of Heihe River Basin

In this study, a change detection model, constructed using the Sentinel-1 Synthetic Aperture Radar (SAR) data and the simultaneous Normalized Difference Vegetation Index (NDVI) products from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Landsat 8 sensors, is applied to estimate soil moisture in middle reaches of the Heihe River Basin, and the effects of two key parameters on retrieval accuracy are comprehensively investigated. The results show that: (1) when constructing the empirical relationship between backscattering coefficient difference ( \mathrm{\Delta } \sigma ) and Vegetation Index (VI) required by change detection model, the optimal sampling ratios in the ( \mathrm{\Delta } \sigma - V I ) space are approximately 2% and 4% for MODIS NDVI and Landsat 8 NDVI, respectively; (2) the Landsat 8 NDVI-based change detection model slightly outperforms the MODIS NDVI-based model in soil moisture retrieval accuracy, with Root Mean Square Error(RMSE) of 0.040 m³/m³ and 0.044 m³/m³respectively; (3) for the key parameters of the change detection method, replacing the ground-based initial soil moisture and scaling factor (maximum soil moisture difference between two adjacent dates \mathrm{\Delta } M s_{max} ) by the low-resolution SMAP/Sentinel-1 L2_SM_SP data will increase the RMSE by 0.01 m³/m³ and 0.04 m³/m³ respectively. Comparing to the parameter of initial soil moisture, the error in soil moisture scaling factor will lead to more significant degradation in the performance of the change detection method, thus it is recommended to use the high precision scaling factor for soil moisture estimation. This study confirms the promising potential of Sentinel-1 data for retrieving high-resolution soil moisture via change detection method and provides practical insight into its application.     

Nanoporous Al‐Ni‐Co‐Ir‐Mo High‐Entropy Alloy for Record‐High Water Splitting Activity in Acidic Environments

Ir‐based binary and ternary alloys are effective catalysts for the electrochemical oxygen evolution reaction (OER) in acidic solutions. Nevertheless, decreasing the Ir content to less than 50 at% while maintaining or even enhancing the overall electrocatalytic activity and durability remains a grand challenge. Herein, by dealloying predesigned Al‐based precursor alloys, it is possible to controllably incorporate Ir with another four metal elements into one single nanostructured phase with merely ≈20 at% Ir. The obtained nanoporous quinary alloys, i.e., nanoporous high‐entropy alloys (np‐HEAs) provide infinite possibilities for tuning alloy's electronic properties and maximizing catalytic activities owing to the endless element combinations. Particularly, a record‐high OER activity is found for a quinary AlNiCoIrMo np‐HEA. Forming HEAs also greatly enhances the structural and catalytic durability regardless of the alloy compositions. With the advantages of low Ir loading and high activity, these np‐HEA catalysts are very promising and suitable for activity tailoring/maximization.     

超低比例导电涤纶与棉混纺产品的设计与开发

探讨超低比例导电涤纶与棉混纺产品的生产工艺及抗静电性能。测试分析了不同比例导电涤纶对混和纤维导电性能的影响,并进行了超低比例导电涤纶与棉混纺纱、布产品的试制与性能测试。结果表明:导电涤纶与棉混和纤维的体积比电阻随着导电涤纶含量的增加而减小,但超过1%后,体积比电阻的下降幅度趋缓;含有0.5%~1%导电涤纶纤维的纺织品可以满足一般的抗静电要求,并具有较好的抗静电耐久性;采用梳棉机后部棉卷定量混和喂入方法可以保证正确的混和比例和均匀的混和效果;导电涤纶含量是影响纺织品抗静电性能的主要因素,混纺纱线密度、织物的组织结构等对抗静电性能影响不大。     

裂隙岩体巷道中的"危石"预测模型

论述了裂隙岩体中的结构面的产状、分布、密度和结构面的内摩擦角的统计模型,提出了多组结构面同时存在的分组结构面间距统计法则,阐述了结构面的产状、迹线长度等几何参数和内摩擦角的模拟模型,引用块体理论和Bayes推测公式建立了巷道围岩中的"危石"预测模型.     

AP1000稳压器波动管竖直管段空气-水CCFL实验研究

使用竖直管代替波动管模型开展稳压器波动管竖直管段内空气-水两相逆流限制(CCFL)特性可视化实验研究。实验现象表明:竖直管与上容器接口处的局部CCFL决定了进入竖直管内的液相流量;竖直管内的局部CCFL决定了从竖直管流出的液相流量;两处局部CCFL均随空气流量的增大而增强。在较低气量情况,进入竖直管内的液相能够完全或大部分流出,竖直管内的局部CCFL较弱,上容器和竖直管接口处的局部CCFL在整体CCFL中占主导地位,整体CCFL程度随着上容器液位升高而略有增强。在高气量情况,从上容器进入竖直管的液相大部分或者完全被限制而不能向下流出,竖直管内的局部CCFL强烈,在整体CCFL中占主导地位,整体CCFL特性不受上容器液位变化的影响。通过实验数据拟合得到了新的稳压器竖直管CCFL模型。稳压器波动管CCFL数据和稳压器竖直管CCFL数据基本重合,表明波动管CCFL主要由CCFL-U决定。     

多用途放射性废物焚烧系统工程验证试验

对建立的多用途放射性废物焚烧系统，进行了工程验证试验。试验主要包括固体废物（包括树脂）和废油焚烧及烟气净化时系统的性能测定、非放示踪试验、72h连续运行考验等。经过共计500多小时的试验，验证了工艺流程、主要设备结构、仪表测控及系统安全等设计的可行性和可靠性；系统运行平稳，设备及仪表工作正常。本系统可一炉多用，其处理能力、减容系数、焚烧灰中残炭率以及系统总去污系数等指标，均达到了设计要求。     

Ku波段低相噪推-推式VCO单片集成电路

基于InGaP-GaAs HBT工艺设计了一款Ku波段推-推式压控振荡器(VCO)微波单片集成电路(MMIC)。采用改进的虚地反馈法对基本振荡单元的奇偶模进行了分析,用谐波平衡法对相位噪声和输出功率进行了优化设计。用ADS软件完成了原理图和电磁场仿真,用Candence Virtuoso完成了版图设计。此VCO MMIC频率覆盖14.5～15 GHz,在2.2 mm×1.2 mm的面积内集成了变容二极管、谐振电路、负阻产生电路,具有体积小、成本低、相位噪声低等特点。在4.2 V单电源电压下,其静态电流为150 mA,典型输出功率为10 dBm,频偏为100 kHz时的单边带相位噪声为-105 dBc/Hz。     

联合时变低通与改进形态学滤波的智能在线称量方法研究

针对检重秤在复杂工业生产环境下,受机械传动、被测物体自身振动和外界随机扰动影响导致的传感器输出信噪比低、称量准确性难以满足要求等问题,提出一种联合时变低通与改进形态学的快速数据处理新方法:时变低通滤波器作为一级滤波,通过在信号跃变时,迭代优化滤波器参数,使边沿信号得以快速响应,有效消除冲击干扰,并抑制称重信号在滤波过程...     

辛基磺酰氟的合成与表征

在氢氟酸存在下，以正辛硫醇（C8H17SH）为原料，NO2为氧化剂合成了辛基磺酰氟（C8H17SO2F）。运用IR、^1HNMR、GC—MS分析技术对辛基磺酰氟进行了表征。反应不产生副产物，二辛基二硫（C8H17SSC8H17）可回收为反应原料。并探讨了辛基磺酰氟的工业应用前景。