改进的QuEChERS法结合液相色谱-高分辨质谱筛查热带水果中33种新烟碱类杀虫剂及杀菌剂

该文采用改进的QuEChERS法结合液相色谱－四极杆－飞行时间质谱（LC－Q－TOF MS）建立了一种检测4种热带水果（芒果、香蕉、释迦和莲雾）中33种农药（包括8种新烟碱类杀虫剂、25种杀菌剂）残留的分析方法。比较萃取溶剂体积、萃取盐种类以及净化剂种类和用量对样品提取与净化的影响。在最优条件下,采用LC－Q－TOF MS对样品进行检测,基质匹配外标法定量分析。该方法可有效降低基质效应,33种农药在各自线性范围内线性关系良好,相关系数（r2）均大于0.99。4种热带水果的筛查限（SDL）为0.5～20 μg/kg,定量下限（LOQ）为0.5～50 μg/kg。方法的准确度与精密度通过芒果基质的加标回收实验进行验证,在1、2、10倍定量下限的加标水平下,33种农药的回收率为70.5%～116%,相对标准偏差（RSD,n = 5）均不大于20%。方法成功用于102批热带水果实际样品的筛查。该方法具有前处理操作简单、快速、灵敏的特点,适用于热带水果中新烟碱类杀虫剂及杀菌剂残留的检测。     

Small Cell Enhancement物理层关键技术研究

作为移动网络解决热点覆盖和数据分流的有效途径,Small Cell在实际部署时仍面临着小区间干扰、移动性管理、回程承载、负荷均衡、维护和优化等难题。为有效克服和优化这些问题,在其演进技术Small Cell Enhancement中,分别从提高频谱效率和协作能力2个方向在关键的物理层提出了一系列潜在技术方案,从而进一步提高系统容量、均衡系统负载,同时更好地兼容现有LTE/LTE-A网络体系。     

湖南经视4K/HD IP微集群新闻演播室的改造设计

本文从湖南经视内容生产技术支撑的目标需求实际出发,对微集群新闻演播室的切换路由、音频、监看、周边、通话、坐席管理、信源接入等子系统的设计进行了探讨和论述。     

3-甲基-4-乙基-5-[2(或4)-吡啶基]-1,2,4-三唑银(Ⅰ)配合物的合成、晶体结构和光学性质

以3-甲基-4-乙基-5-（2-吡啶基）-1,2,4-三唑（L）和3-甲基-4-乙基-5-（4-吡啶基）-1,2,4-三唑（L''）为配体分别合成了2个银（Ⅰ）配合物[Ag₂（μ-L）₂L₂（NO₃）₂]（1）和{[Ag₂（μ-L''）₂（H₂O）₂]（NO₃）₂}_n（2）,测定了X射线单晶结构,用红外光谱、荧光和热重等进行了表征。2个配合物都属于三斜晶系,空间群为P1。晶体结构分析表明2个配合物都具有畸变的四面体结构[AgN₃O]。配合物1是一个双核银（Ⅰ）配合物,NO₃^-参与配位;而配合物2是一个配位聚合物,水分子参与配位。     

Enhancement of φ meson production in p-p and Pb-Pb collisions at SPS energy

The φ meson yield, rapidity and transverse mass distributions in p-p and Pb-Pb collisions at 158 A GeV were studied by the hadron-string cascade model, LUCIAE. By adjusting the width parameter in q-q Gaussian like transverse momentum distribution in string fragmentation to fit the NA49 data ofφ meson transverse mass distribution in p-p collisions, the obtained φ meson rapidity distribution in p-p collisions, the rapidity and transverse mass distributions in Pb-Pb collisions, and theφ meson enhancement factor in Pb-Pb relative to p-p collisions were compatible with corresponding NA49 data, which might be attributed to the collective effect in gluon emission of string and the reduction of strange quark suppression mechanisms involved in the LUCIAE model.     

5G终端业务发展趋势及技术挑战

2020年,5G通信将实现人与人、人与物、物与物之间的真正无缝连接,其网络技术发展趋势集中于高频段毫米波通信、超密集小区覆盖、终端直连D2D、同时同频全双工、大规模天线阵列、多天线接入方式协作、新型异构网络等方面。未来5G终端将主要应用于广阔的移动互联网和物联网领域。同时,5G终端将面临高速率、高可靠性、高密度通信、高移动性、低时延、低功耗、低成本、多元化终端形态和多种无线接入方式融合等技术的挑战。     

UICC初始化访问分析与优化

针对移动终端初始化时对UICC访问过程的优化需求，介绍了UICC初始化过程中的分阶段分析方法，并分别从时间参数、UICC访问时间、APDU命令和文件访问等四个方面结合具体实验数据加以整理和分析，最后从数据传输、APDU命令和访问文件等方面提出合理的UICC访问优化建议。     

A Toy Model for Estimation of the Event Plane Non-Flat Effect on an Elliptic Flow in Heavy Ion Collision

In heavy ion collision, the event plane is a key parameter defined as the plane composted by the impact parameter b and beam axis z, It is a crucial reference for various observables, which focus on the initial spatial anisotropy of the overlap region in heavy ion collision. We notice that in some recent heavy ion collision experiments, due to potentially inefficient or even the invalidity of experimental facilities, the reconstructed event plane, which is used in elliptic flow study, may be biased towards a non-flat distribution. In this study, we develop a toy model for fast estimation of the bias effect and its influence on the elliptic flow. The possible azimuthal bias of the detector is firstly studied by varying the part of its azimuthal information. We also study on the limit acceptance of the detector, which will be used to measure the particle of interest in an elliptic flow. The outcomes are presented by comparing the flow study results with or without the non-flat effect on the event plane.