基于ARINC818机载音视频的测试方案设计

某型飞机在试飞测试任务过程中,需要对多路机载音视频进行抽引、采集、记录与遥测,用于飞机实时动态监控与事后回放分析。该型飞机的显控数据采用ARINC818(又名航空电子视频总线Avionics Digital Video Bus)专用图像传输协议进行光纤视频传输,对ARINC818总线视频的抽引采集在试飞任务中为首次。由于目前机载采集系统的限制,本文设计了一种基于ARINC818的机载测试系统,满足了该型飞机多通道、高分辨率、多视频格式的信号采集记录。     

An assessment of the sharpness of carotid artery tissue boundaries with acquisition voxel size and field strength

A measure of the sharpness of vessel wall interfaces in carotid artery MRI may be useful for assessing the conspicuity of the wall's features. An edge detection technique was used to measure the signal intensity gradients in 2D time-of-flight (2D-TOF) and double-inversion recovery black-blood (DIR-BB) carotid artery images of normal subjects that were acquired at 1.5 T with 0.55 x 0.55 x 2.0-mm (0.6 mm3) acquisition voxels and zero filled to reduce the in-plane reconstructed voxel size by one half in each dimension as well as with 0.27 x 0.27 x 2.0-mm (0.15 mm3) acquisition voxels and at 3.0 T with 0.27 x 0.27 x 2.0-mm (0.15 mm3) acquisition voxels using surface coils. The gradient intensities of the lumen-to-background interface varied closely with the contrast-to-noise ratio of the 2D-TOF imaging. For the DIR-BB imaging, in which higher spatial frequency artery structures are visible, the gradient intensities at the interfaces were higher than theoretically predicted at both field strengths with smaller acquisition voxels. The use of acquisition voxels smaller than those previously used at 1.5 T can improve the visualization of carotid artery structures at 1.5 and 3.0 T with surface coil reception.     

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介绍了在QNX实时操作系统下分布式采集控制程序的编写。现场机器负责数据采集存储,并按照预设的参数进行控制。控制室机器负责参数设置与波形的显示,同时负责在控制室远程启动现场机器程序并返回运行的状态,以便在现场机器程序出现异常情况下采取相应的措施。经测试,系统的实时性和可靠性很好地满足了EAST装置LHCD系统单管测试的需要。     

基于粒度计算的探索性分析建模研究

从现有探索性分析模型建模方式的局限性出发,提出了探索性分析模型的粒度原理,建立了基于粒度计算的探索性分析模型,给出了该模型的因素集粒化、因素水平值域粒化以及混合粒化三种粒度获取方式,针对探索性分析模型的追溯问题,分析并建立了粒度空间各层次间的层级关联映射和软构层映射.在此基础上,能够建立探索性分析模型的一般性数学描述.     

Measurement of the feedback coefficient by monitoring the power difference at power jump point in self-mixing vibration signal

This paper proposed a new method for measuring the feedback coefficient in the self-mixing interference. In experiment, the value of feedback coefficient is obtained by measuring the power difference at power jump point that based on the self-mixing vibration sensing system. It realized the measurement of feedback coefficient in range of 1–7.8 and shows a good agreement with the theoretical derivation and the corresponding simulation. Meanwhile, there is a good fitting result with the determination coefficient of 0.98 and line-width broadening factor of 3.245 respectively, which also realized measurement of feedback coefficient and line-width broadening factor at the same time.     

自由空间光通信地面演示系统光束APT设计与实现

自由空间光通信将成为未来空基通信一种可行且诱人的通信手段。光束的捕获、对准和跟踪是自由空间光通信中必须解决的关键技术之一。本文对设计的自由空间光通信地面演示系统进行分析。详细论述演示系统的组成及功能，APT伺服系统的设计和演示实验的工作流程。最后给出实验测试结果。     

固相时间分辨荧光免疫分析仪数据采集系统设计

荧光寿命和时间分辨荧光光谱在时间分辨荧光免疫分析中具有十分重要的地位。本文设计了一款基于CPLD的实时、高速数据采集系统,该系统实现几百纳秒到十几个毫秒范围的荧光测量。使用VHDL硬件描述语言设计CPLD内部的逻辑电路,内部共设置了13种采样频率,测量过程中,可多次选择不同的采样频率,直到得出最理想的结果。采样个数在1-8192范围内任意设置。采样时间及延迟时间可根据需要在1-65535微妙范围内调节,分辨率为1微妙。测量结果表明,该系统满足荧光寿命和时间分辨荧光光谱测量的要求。     

基于LabVIEW和GPIB的数字示波器数据自动采集系统设计

介绍了一种利用数字示波器和工控机建立的数据自动采集系统。通过GPIB接口,用一台工控机对多台数字示波器进行控制,实现对信号数据的采集、处理并将处理结果存入数据库中。采用这种方法建立的系统简单、经济、通用性强,具有一定的实用价值。     

Productivity enhancement in a cross-flow ultrafiltration membrane system through automated de-clogging operations

A membrane system only has a limited operational lifetime, whereby it becomes so severely fouled that continued operation must be stopped. In the cross-flow configuration of membrane filtration of wastewater, both increased cross-flow velocities and decreased operational transmembrane pressures can be used to decrease membrane fouling and extend the life cycle of the membrane separation process. The study found that an optimised usage of two de-clogging techniques, with a 1 h production period followed by a 1 min relaxation period and then a 1 min high cross-flow rate period, resulted in a net productivity increase of 14.8%.

The study involved a detailed investigation into the utilization of two automated cleaning techniques to reduce fouling problems encountered when cross-flow membrane systems are operated with high permeate flux rates. The two cleaning techniques studied were periodic membrane relaxation and a periodic high rate cross-flow. During both the relaxation and high rate cross-flow periods, permeate production was stopped. This results in an operational loss in productivity. When each cleaning technique was operated individually, there was a net productivity decrease of 0.7%, due to the 3.2% operational loss due to cleaning technique being implemented.

The system was developed using a Programmable Logic Controller (PLC) and a Supervisory Control and Data Acquisition (SCADA) system to accurately control and monitor the process.