气球中N-亚硝胺及其前体物迁移量的测定与NDMA的儿童致癌暴露风险分析

用Sep-PakAC2串联Drycartridges固相萃取小柱对气球中的7种挥发性N-亚硝胺进行分离净化,并用气相色谱-串联质谱法对其进行定性与定量分析。方法对气球中N-亚硝胺及其前体物的检出限分别为1.25μg/kg和5.00μg/kg。对空白样品进行添加量为2.5μg/kg的加标回收实验,回收率为85%～103%,RSDs（n=3）≤4.6%。分析的气球样品中,N-亚硝基二甲胺（NDMA）及其前体物的检出频率最高;其次是N-亚硝基二乙胺（NDEA）及其前体物;N-亚硝基吗啉（NMOR）、N-亚硝基二丙胺（NDPA）和N-亚硝基哌啶（NPIP）及其前体物均未检出;7种N-亚硝胺及其前体物的总迁移量分别为0.036～0.964mg/kg和0.259～8.436mg/kg。6个月～4岁儿童通过口直接接触单个气球样品造成的NDMA的暴露量集中在0.010～0.030mg/kg体重,具有潜在的致癌暴露风险。     

Fluorescence Depolarization Due to Excitation Energy Migration in Polymeric Micelles: A Monte Carlo Study

Cores of block copolymer micelles have been studied by Monte Carlo simulation. Core-forming chains have been modeled as self-avoiding chains enclosed in a spherical cavity and tethered to its surface. A fraction of the untethered end segments of chains (18–53%) has been treated as fluorescent probes. The time-dependent solution of the Pauli master equation that describes excitation energy migration among probes has been averaged in an ensemble of 10⁴ simulated cores. We have studied the dependence of the depolarization function G ^S(t), i.e., the probability that the originally excited probe is still excited at time t, on the chain length and on the energy migration critical radius of the probe. Cores with randomly solubilized probes and with clusters of probes have been also studied for comparison.     

高架机动雷达总体结构设计与关键技术分析

介绍了高架机动雷达的国内外发展现状及问题,从结构设计的角度论述其总体设计内容与思路,具体分析了高架机动雷达的结构关键技术。文章提出了天线在举高状态下的设计难点和解决方法,论述了天线举升机构的一般设计过程要点,对垂直举升机构进行有限元设计分析,以一种高架机动雷达为例阐述了机动性设计的要点及实现方法,对升降机构的举升过程进行了仿真分析。     

介电弹性球膜的动力稳定性分析

介电弹性体结构具有卓越的力电性能,然而由于其大变形特性,在动态工作模式下极易出现各类失效问题,这极大阻碍了其工程应用.论文研究与力电失稳行为直接相关的理想介电弹性球膜动力稳定性问题.首先据虚功原理建立电压及压力共同作用下关于伸长比的动力学方程,系统自由能由弹性应变能与静电能组成,而前者基于Mooney-Rivlin模型表出.通过系统首次积分解析给出稳态响应峰值与阶跃电压/阶跃压力的关系曲线,其与静态平衡曲线的交点决定了临界电压/临界压力.研究表明:给定任意电压,材料参数存在某阈值,当超过该值后系统始终保持稳定;对于任意非零压力值,存在类似材料参数阈值;而当压力恰为零时,则始终存在临界电压值,超过该值则系统动力不稳定.     

基于四元数方法的绳系机器人姿态控制

为进一步提升空间绳系机器人在轨服务能力,研究了空间绳系机器人抓捕目标后的复合体姿态控制问题.首先,基于四元数原理,描述了空间绳系机器人在抓捕目标后组成的复合体姿态,建立了空间绳系机器人系统的动力学方程;其次,针对带约束的动力学控制方程,结合投影技术和Runge Kutta方法,构造了一种保四元数范数的显式投影方法;最后,通过数值实验,验证了所提出数值方法的有效性,同时分析了采用系绳和推力器同时控制,采用系绳、推力器相互切换控制,以及单独采用推力器进行控制这3种方式对空间绳系机器人抓捕目标后的复合体姿态的控制效果和能量消耗.     

Near space radiation dosimetry in Australian outback using a balloon borne energy compensated PIN diode detector

This paper reports the near space ballooning experiment carried out at Australian outback town West Wyalong (33°51′S, 147°24′E) on 19 July 2015. Several dedicated electronic detectors including digital temperature and acceleration (vibration) sensors and an energy compensated PIN-diode gamma ray dosimeter were installed in a thermally insulated Styrofoam payload box. A 9 V Lithium-Polymer battery powered all the devices. The payload box was attached to a helium-filled latex weather balloon and set afloat. The balloon reached a peak burst altitude of 30 km and then soft-landed aided by a self-deploying parachute 66.2 km away form the launch site. The payload box was retrieved and data collected from the electronic sensors analysed. The integrated cosmic ray induced photon ambient dose equivalent recorded by the PIN diode detector was evaluated to be 0.36 ± 0.05 μSv. Furthermore, a high-altitude extended version of commercially available aviation dosimetry package EPCARD.Net (European Program package for the Calculation of Aviation Route Doses) was used to calculate the ambient dose equivalents during the balloon flight. The radiation environment originated from the secondary cosmic ray shower is composed of neutrons, protons, electrons, muons, pions and photons. The photon ambient dose equivalent estimated by the EPCARD.Net code found to be 0.47 ± 0.09 μSv. The important aspects of balloon based near-space radiation dosimetry are highlighted in this paper.     

双余度多通道系留气球测控系统的设计

系留气球是一种通用航空平台,测控系统是其核心电子设备.为了满足测控系统稳定可靠、能够长时间连续滞空工作的要求,采用球控单机双冗余热备份、双通道高精度微差压检测、故障相关识别、自适应光纤和无线通信通道切换等设计方法.通过执行世博安保任务,测控系统连续7个月不间断无故障工作,验证了测控系统具有高可靠性和安全性,能够满足系统...