Volatile and non-volatile compound profiles of commercial sweet pickled mango and its correlation with consumer preference

Sweet pickled mango named Ma-Muang Bao Chae-Im is a traditional preserved mango from Hat Yai, Thailand. This study investigated (I) volatile and non-volatile compound profiles of commercial Ma-Muang Bao Chae-Im and (II) their relationship to consumer preference. Untargeted metabolomics profiling was performed by gas chromatography-mass quadrupole-time of flight analysis. There were 117 volatile and 44 non-volatile compounds annotated in six commercial brands of Ma-Muang Bao Chae-Im. Furthermore, 46 volatile and 19 non-volatile compounds’ discriminant markers were found by Partial least square discriminant analysis. Among those markers, sorbic and benzoic acid were observed in several brands; moreover, the combination of both compounds altered the volatile profile, especially the ester group. Partial least square regression revealed that overall consumer liking is correlated to 1-heptanol; 1-octanol; acetoin; acetic acid, 2-phenylethyl ester; D-manitol; terpenes and terpenoids, while firmness to sucrose and L-(-)-sorbofuranose. On the other hand, most ester compounds were not related to consumer preference.     

基于残差决策的自动飞行控制系统远程实时故障诊断

针对自动飞行控制系统结构复杂、关联部件众多,发生故障时诊断时间长,从而影响飞机运行效率的问题,提出一种基于飞机通信寻址报告系统(ACARS)的远程实时故障诊断方案。首先,分析自动飞行控制系统的故障特点,设计搭建检测滤波器;然后,利用ACARS数据链实时发送的自动飞行控制系统的关键信息进行相关部件的残差计算,并根据残差决策算法进行故障诊断及定位;最后,针对不同故障部件残差间的差异大、决策门限无法统一的缺点,提出基于二次差值的残差决策改进算法,减缓了检测对象的整体变化趋势,降低了随机噪声和干扰的影响,避免了将瞬态故障诊断为系统故障的情况。实验仿真结果表明,基于二次差值的改进残差决策算法避免了多决策门限的复杂性,在采样时间为0.1 s的情况下,故障检测所需时间大约为2 s,故障检测时间大幅降低,有效故障检测率大于90%。     

机载光电雷达它机试飞技术研究

机载光电雷达受平台及大气环境影响较大,而它机试飞能有效规避研制风险,是产品研制的必经阶段。本文介绍了机载光电雷达它机试飞试验系统组成、试验流程和数据处理等内容。经工程验证,实施过程满足任务需求,对其他光电系统的它机及本机试飞具有参考价值。     

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.     

Hygrothermal deformation of orthotropic nanoplates based on the state-space concept

This paper deals with the investigation of the effect of hygrothermal conditions on the bending of nanoplates using Levy type solution model employing the state-space concept. The nanoplates are assumed to be subjected to a hygrothermal environment. The two-unknown function plate theory is used to derive the governing differential equations on the basis of Eringen's nonlocal elasticity theory. The governing equations contain the small scale effect as well as hygrothermal and mechanical effects. These equations are converted into a set of first-order linear ordinary differential equations with constant coefficients. Analytical solution of bending response for nanoplates under combinations of simply supported, clamped and free boundary conditions is obtained. Comparison of the results with those being in the open literature is made. The influences played by small scale parameter, temperature rise, the degree of moisture concentration, boundary conditions, plate aspect ratio and side-to-thickness ratio are studied.     

对空监视雷达探测威力检飞的几个问题

以新的观点论证了对空监视雷达探测威力检验飞行中所需的采样点数和飞行架次，讨论了预警机雷达威力检飞的特殊问题，包括地区选择、航线设计和目标机标定等。     

地地战术导弹飞行可靠性指标评定方法

在小子样情况下 ,利用系统和分系统试验数据对导弹的飞行可靠性指标进行评定 ,从数学上说是系统可靠性综合问题 .运用MML SR方法对新型号地地战术导弹的飞行可靠性指标进行评定 ,避免了MML方法在遇到无失败单元时不适用的缺陷 ,在利用地面试验信息方面有其明显优势 ;运用Bayes方法对改进型导弹的飞行可靠性指标进行评定 ,将不同试验阶段的多源试验信息作为验前信息 ,扩大了信息量 .最后 ,对两种方法在工程应用上遇到的问题进行了讨论 ,并给出了解决方法 .     

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。     

关于飞行力学的再思考

对多年来国内外有关飞行力学的发展过程、研究范畴、分类，以及问题表述方式等重新进行了一些考察和思考．从学术和实践的观点，对飞行力学的体系结构和问题表述方式等进行了讨论，并提出了个人的一些看法和建议．