用于检测血清中毒品的频率选择表面的设计

本文基于频率选择表面(Frequency Selective Surface,FSS)的空间滤波性能设计了一个响应频带在可见光及更短波段的带阻型频率选择表面,用于血清中冰毒的检测。结合已有的设计经验和仿真测试结果提出了双屏方环FSS单元结构,通过为其设定适当的结构参数初步实现了600～1 000 THz的阻带。在此基础上分析了影响频率选择表面传输性能的各项参数,分析了方环尺寸大小、中间介质层厚度、介质层介电常数等对FSS传输性能的影响;基于此,综合考虑各项参数的影响,利用仿真软件HFSS进行了多次仿真求解,得到最优情况下的方环外边长为120 nm,内边长为100 nm,单元周期为140 nm,介质厚度为60 nm,金属贴片为厚度10 nm的银,介质层材料为介电常数是2.08的Neltec NY9208。所得到的最优情况下的FSS单元结构阻带为500-1 000 THz,带内透射率可达到5%以下,通带为1 000-1 600 THz,带内透射率可达到90%以上,可以实现滤除血清自身荧光信号的设计目标。     

基于SIP协议的模拟电台语音通信系统设计

为了提高模拟电台训练系统的仿真程度,在模拟电台语音通信系统中以计算机网络通信技术为核心,构建一种基于SIP协议的语音通信技术.经过实验测试,在多部电台模拟器之间相互构建语音组网通信时延小于200ms,音质清晰,能够清楚分辨出发话人的语音特征,满足了设计的要求.     

超高效液相色谱法检测土壤中硝基呋喃类药物残留

建立超高效液相色谱法检测土壤中硝基呋喃类药物残留。通过单因素和正交设计试验,考察了超声时间、提取温度、提取次数对硝基呋喃类药物残留回收率的影响。最优提取条件为超声时间10 min、提取温度45℃、提取次数为4次。硝基呋喃类药物的质量浓度在1~4μg/mL范围内与色谱峰面积成良好的线性关系,线性相关系数均大于0.9999。加标回收率为74.34%~102.52%,测定结果的相对标准偏差为0.91%~4.49%(n=6)。该方法简单、快速,测定结果准确可靠,可用于土壤中硝基呋喃类药物残留量的测定。     

反散射理论导出He-Ne相互作用势

以Ｈｅ原子束与Ｎｅ原子束交叉碰撞实验数据为基础。以反散射方法为手段，理论上导出Ｈｅ－Ｎｅ原子相互作用势，所得的势呈显出ｖａｎ ｄｅｒ Ｗａａｌｓ势的特征，即短程为强排斥，中程为碗形吸收，远程为零，这样的势能正确的，符合实验的弹发型用射微分截面。     

压电点火器的发电特性研究

本工作研究了普通压电打火机中的压电点火器发电特性,以调查其产生的电能能否满足小型电子设备对电能的需求。研究发现压电打火器能够产生高达千伏的高压脉冲,于是通过接入整流桥、电容和稳压器来对高压脉冲进行整流和稳压。研究还发现,接入负载的阻值对压电点火器的输出功率有急剧影响,当阻值为0.22 kΩ时输出功率达到极大值0.26 mW,基本可以满足一些小型电子设备的电能需求。     

脉冲位置调制对脉冲式光纤激光器调制速率的影响

脉冲式光纤激光器受到其重复频率的限制,导致其数据传输速率较低,严重影响了其在通信领域的应用。为了改善其性能并使其能更好地应用到通信领域,针对脉冲式光纤激光器的这种缺点,通过三种脉冲位置调制(PPM)调制方式对其进行调制并对其性能的影响进行了实验研究。通过改变三种PPM调制的调制位数脉冲时隙宽度对脉冲式光纤激光器的调制速率的影响以及三种PPM调制方式对脉冲式光纤激光器的输出功率误码率的影响进行了仿真研究。分析结果表明,单脉冲位置调制(L-PPM)调制方式最适合脉冲式光纤激光器,可以将重复频率为200kHz的脉冲式光纤激光器的调制速率提高到1.387Mbit/s,该结果有利于脉冲式光纤激光器在通信中的应用。     

使用多准则决策法的环境感知路由协议

本文提出了一个新的移动节点的分级方案，它是基于两个多准则决策方法的结合，即模糊环境下的层次分析法（AHP）和近似理想解决方案的排序性能技术（TOPSIS）。模糊AHP是用来分析簇首选择问题的结构，并确定这个准则的权重；而模糊TOPSIS用于获得最终的移动节点等级值。基于节点等级，我们提出一种新的簇，它使用能够选择最佳簇首和最佳路径的路由算法。仿真结果表明，该方法提高了网络的精度和寿命，降低了网络开销。     

Studies of an LL-type 500 MHz 5-cell superconducting cavity at SINAP

A low loss- (LL) type 500 MHz 5-cell superconducting niobium prototype cavity with a large beam aperture has been developed successfully including the optimization, the deep drawing and electron beam welding, the surface treatment and the vertical testing. The performance of the fundamental mode was optimized and the higher order modes were damped by adopting an enlarged beam pipe for propagation. Surface preparation or treatment including mechanical polishing, buffered chemical polishing and high pressure rinsing with ultra-pure water and so on was carried out carefully to ensure a perfect inner surface condition. The vertical testing results show that the accelerating voltage higher than 7.5 MV was obtained while the quality factor was better than 1× 10⁹ at 4.2 K. No obvious multipacting or field emission was found during the test. However, a quench happened while increasing the field a little higher than 7.5 MV that at present limited the cavity performance.     

Theoretical Studies on the Molecular Structures and Thermodynamic Properties of Polychlorinated Fluorenes

Geometric structures of 135 polychlorinated fluorene (PCFR) molecules were optimized using density functional theory (DFT) at the B3LYP/6-311G** level and their thermodynamic properties in the ideal gas state were calculated. The relations of these thermodynamic properties with the number and position of chlorine atoms were also explored, from which the relative stability of PCFR congeners was theoretically proposed according to the magnitude of the relative standard Gibbs free energy of formation (Δr,fGθ). The results show that the geometric configuration of PCFR isomers is determined by the position of chlorine atoms. There exist two types of intramolecular weak interactions, i.e., C-H···Cl and Cl···Cl interactions in PCFR molecules. The change of ΔfHθ and ΔfGθ of most stable PCFR isomers with increasing the number of chlorine atoms is different from that in most unstable PCFR congeners. The values of ΔfHθ and ΔfGθ for PCFR isomers with the same number of chlorine atoms strongly depend on the position of chlorine atoms and the relative stability of PCFR congeners is mainly determined by intramolecular delocalized π bond and Cl···Cl nuclear repulsive interaction.