Apparent power-law distributions in animal movements can arise from intraspecific interactions

Lévy flights have gained prominence for analysis of animal movement. In a Lévy flight, step-lengths are drawn from a heavy-tailed distribution such as a power law (PL), and a large number of empirical demonstrations have been published. Others, however, have suggested that animal movement is ill fit by PL distributions or contend a state-switching process better explains apparent Lévy flight movement patterns. We used a mix of direct behavioural observations and GPS tracking to understand step-length patterns in females of two related butterflies. We initially found movement in one species (Euphydryas editha taylori) was best fit by a bounded PL, evidence of a Lévy flight, while the other (Euphydryas phaeton) was best fit by an exponential distribution. Subsequent analyses introduced additional candidate models and used behavioural observations to sort steps based on intraspecific interactions (interactions were rare in E. phaeton but common in E. e. taylori). These analyses showed a mixed-exponential is favoured over the bounded PL for E. e. taylori and that when step-lengths were sorted into states based on the influence of harassing conspecific males, both states were best fit by simple exponential distributions. The direct behavioural observations allowed us to infer the underlying behavioural mechanism is a state-switching process driven by intraspecific interactions rather than a Lévy flight.     

模拟光耦SLC800在转台系统中的应用

在大功率转台控制系统中．存在着较大的电压干扰和电磁兼容问题。在转台的控制精度和驱动功率不断提高的情况下．本文使用模拟光耦隔离器件SLC800重新设计了转台中的某部分模拟电路．将功率放大电路和控制电路隔开，来增强系统的抗干扰能力和运行的可靠性。实验结果的分析和转台的运行表明：应用模拟光耦进行隔离，有效地消除了转台控制中的干扰和电磁兼容。     

飞行时间二次离子质谱--强有力的表面、界面和薄膜分析手段

二次离子质谱（Secondary ion mass spectrometry，简称SIMS）是一种对表面灵敏的质谱技术，建立在表面各种类型带正、负电荷原子或分子发射的基础上。用飞行时间（Time of flight，简称TOF）仪器对这些二次离子进行质量分析，能确保并行质量登录、高质量范围、高流通率下的高分辨和精确质量测定这些优异性能。配合细聚焦扫描一次离子束，可在优于1nm的高深度分辨和优于50nm的横向分辨本领下，实现对表面优于单层ppm(百万分之一）量级的极高检测灵敏度。当今TOF－SIMS已发展为一种成熟且完善的表面分析技术。极高的灵敏度，再加上即使对大分子及不易挥发性分子都独具的敏感性，使它成为很多高技术领域不可缺少的分析手段，这些领域包括微电子学、化学和材料科学以至纳米技术和生命科学等。本文简述了TOF－SIMS的原理、仪器及其多方面的应用和展望。     

基于神经网络观测器的飞控传感器在线故障诊断

为提高无人机飞行安全可靠性,针对飞行控制系统中常出现的传感器故障以及非线性气动力模型参数难以确定的问题,提出了基于BP神经网络观测器估计的故障诊断方法;引用LM改进算法对网络参数进行调整,构造了神经网络观测器模型逼近非线性系统,并运用于飞行控制系统进行在线数字仿真,对垂直陀螺输出卡死故障、恒偏差故障和恒增益故障分别进行仿真分析;仿真结果表明,所设计神经网络观测器可以有效估计系统输出,在线诊断传感器故障。     

飞行器电磁窗耐雨蚀复合涂层的制备

研制了电磁窗用耐雨蚀底漆和耐雨蚀面漆，介绍了该配套涂料体系的制备工艺，并列举了其性能指标。讨论了耐雨蚀面漆中聚酯树脂、多元醇和颜料对其性能的影响，施工工艺对耐雨蚀涂层与底涂层之间配套性能的影响。     

Single frame correction of motion artifacts in PMD-based time of flight cameras

One of the leading time of flight imaging technologies for depth sensing is based on Photonic Mixer Devices (PMD). In PMD sensors each pixel samples the correlation between emitted and received light signals. Current PMD cameras compute eight correlation samples per pixel in four sequential stages to obtain depth with invariance to signal amplitude and offset variations. With motion, PMD pixels capture different depths at each stage. As a result, correlation samples are not coherent with a single depth, producing artifacts. We propose to detect and remove motion artifacts from a single frame taken by a PMD camera. The algorithm we propose is very fast, simple and can be easily included in camera hardware. We recover depth of each pixel by exploiting consistency of the correlation samples and local neighbors of the pixel. In addition, our method obtains the motion flow of occluding contours in the image from a single frame. The system has been validated in real scenes using a commercial low-cost PMD camera and high speed dynamics. In all cases our method produces accurate results and it highly reduces motion artifacts.     

Human interaction with policy flight simulators

Policy flight simulators are designed for the purpose of exploring alternative management policies at levels ranging from individual organizations to national strategy. This article focuses on how such simulators are developed and on the nature of how people interact with these simulators. These interactions almost always involve groups of people rather than individuals, often with different stakeholders in conflict about priorities and courses of action. The ways in which these interactions are framed and conducted are discussed, as well as the nature of typical results.     

<Emphasis Type="Italic">In situ</Emphasis> monitoring of solid fat content by means of pulsed nuclear magnetic resonance spectrometry and ultrasonics

An ultrasonic technique was developed to study the crystallization process of edible fats on-line. A chirp wave was used instead of the conventional pulser signal, thus achieving a higher signal-to-noise ratio. This enabled measurements to be made in concentrated systems [≈20% solid fat content (SFC)] through a 8.11-cm thick sample without significant signal loss. Fat samples were crystallized at 20, 25, and 30°C at a constant agitation rate of 400 rpm for 90 min. The crystallization process was followed by ultrasonic spectroscopy and a low-resolution pulsed nuclear magnetic resonance spectrometer. Specific relationships were found between ultrasonic parameters [integrated response, time of flight (TF), and full width half maximum] and SFC. TF, which is an indirect measurement of the ultrasonic velocity (v), was highly correlated to SFC (r ²>0.9) in a linear fashion (v=2.601 SFC+1433.0).     

四螺棱往复螺杆挤出机的研制

介绍了四螺棱往复螺杆挤出机的研制情况；着重叙述了新研发的四螺棱往复螺杆与传统的三螺棱往复螺杆的特性，并作了比较和分析；对四螺棱往复螺杆在设计和加工中的难点及其在工作时的“柔性”特征等进行了阐述。     

Flight and landing behavior ofTrypodendron lineatum (Coleoptera: Scolytidae) in response to different semiochemicals

The responses of the striped ambrosia beetle,Trypodendron lineatum (Olivier) (Coleoptera: Scolytidae), to modified drainpipe traps baited with the host attractant ethanol, the aggregation pheromone lineatin, both alone and in combination, were studied in a wind tunnel. Exposure of males to ethanol increased their frequency of steady, upwind flight; however, only lineatin was effective in inducing them to land on and enter the traps. In contrast, exposure of females to either ethanol or lineatin alone resulted in an increased frequency of trap landing and entry. Both compounds released simultaneously did not significantly increase the frequency of trap landing and entry for either sex. These responses are consistent with the life history strategies used by both sexes to seek and colonize suitable host material.