悬浮体进样-基体改进效应石墨炉原子吸收光谱法直接测定土壤中的铅和镉

建立了以悬浮体进样-基体改进效应石墨炉原子吸收法测定污灌区土壤中痕量铅和镉的新方法。以琼脂为悬浮剂、NH₄H₂PO₄作基体改进剂,研究了土壤悬浮液的稳定性和基体改进效应及干扰效应。基于原子化峰值时间的对数值与原子化温度之间的线性关系测得Cd和Pb的表观活化能,探讨了基体改进效应机理。应用标准曲线进行校准, Pb和Cd的检出限分别为9.05×10-10 g·mL-1和1.76×10-11 g·mL-1,Pb和Cd的回收率分别为91%～97%和93%～109%,相对标准偏差为4.2%～7.8%。以土壤标准品作参照, 测得值与标准值相符。     

Effects of atomization conditions on morphology and SOFC anode performance of spray pyrolyzed NiO–Sm0.2Ce0.8O1.9 composite particles

NiO–Sm_0.2Ce_0.8O_1.9 (NiO–SDC) composite particles were synthesized by spray pyrolysis (SP). SP resulted in composite particles of NiO enveloped with SDC and these capsule-type composite particles would reduce aggregation of Ni during the reduction from NiO to Ni metals. SOFC anode microstructures and morphologies of NiO–SDC composite precursor particles much affects on SOFC power densities or anode polarization. Therefore, we focused on atomizing conditions of SP process. Relationship between ultrasonic atomization conditions and morphologies of NiO–SDC composites were investigated by controlling temperatures of atomization vessels. The atomizing temperature changed concentration of mists in the vessel, and mean particle size and particle size distribution were increased with an increase in temperature of the atomization vessels. Some extremely large particles were observed by synthesizing at higher atomization temperatures. Large particles contained voids in the particles. The voids in the composite particles would play a role of pore-formers. SOFC measurement showed the synthesis at the atomizing temperature of 30 °C resulted in the high-performance anode. The atomizing process of SP much affected morphology of anode precursor particles, and the atomizing conditions were important to improve anode performance.     

石墨炉原子吸收光谱法测定中药漏芦中微量镉的研究

本文提出了石墨炉原子吸收光谱法（GFAAS）测定中药漏芦中微量镉的方法,对基体改进剂及其用量进行了选择试验,对石墨炉工作条件进行了优化,对共存离子的影响进行了考察,在优化实验条件下,方法的检出限为0．06ng.mL^-1,精密度（RSD）为2．43％,试样加入回收率为97－105％。     

基于改进PSO的超声雾化电源频率跟踪研究*

超声波雾化技术由于其良好的雾化效果获得了广泛关注，具有极大的研究价值和应用前景。但是在超声雾化的过程中，由于换能器的温度变化、刚度变化以及在水中的负载变化等因素，会产生谐振频率漂移的现象。当工作频率偏移谐振频率时，将造成换能器的工作效率降低和元器件损坏等问题。针对此问题，设计了基于改进粒子群算法优化PID参数的超声雾化电源频率跟踪算法，并对该算法进行频率跟踪的仿真验证和实验对比，在频率跟踪上实现了更好的效果，使换能器能够稳定工作在谐振状态，提高了电源的利用率。     

石墨炉原子吸收法测定高纯镍中痕量铋

本文利用石墨炉原子吸收法，在等温平台条件下直接测定了高纯镍中的痕量铋，并对石墨炉加热程序中的干燥时间，灰化温度及原子化温度进行了优化，同时也考察了介质酸度的影响，试验表明：基体镍对铋的测定有显著的影响，为此对标准系列进行了基体匹配，本方法的特征质量为6．1pg，相对标准偏差为3．6％，加标回收率为99．3％－104％。     

空气介质阻挡放电单个微放电通道发光强度及振动激发温度的空间分布

通过清洗放电方法,在平行平板介质阻挡空气放电中得到了单个稳定的微放电通道（又称放电丝）.测量了从瞬时阳极到瞬时阴极单个放电丝的发光强度及振动激发温度的空间分布.研究表明：在外加电压的每半周中放电丝发光呈现杯型分布,杯底位于瞬时阴极处;振动温度在两平行板间隙的中心处最高而在瞬时阳极处最低. 关键词： 介质阻挡放电 微放电通道 振动温度     

悬浮体制样石墨炉原子吸收光谱法直接测定琥珀中微量镉

报道了以硝酸钯为基体改进剂,采用悬浮体制样石墨炉原子吸收光谱法直接测定琥珀中微量Cd的方法。研究了悬浮剂、试样粒度、基体改进剂、灰化/原子化温度和共存金属离子对分析信号的影响。在优化实验条件下,方法的检出限为9.4 ng·g-1,相对标准偏差(RSD)为6.1%。     

高分辨连续光源石墨炉原子吸收光谱法测定面制食品中的铝

使用微波消解-高分辨连续光源石墨炉原子吸收光谱法测定四种面制食品(挂面、饺子皮、油条和梳打饼干)中铝的含量.样品置于密闭聚四氟乙烯消解罐中经HNO3和H2O2混合溶液完全消解.对微波消解条件、灰化温度和原子化温度进行了优化.确定最佳实验条件为:消解液HNO3和H2O2体积比7∶1,微波功率1 000 W,190℃消解4...     

Sensor studies of the initial stages of the cadmium telluride film formation through vapor deposition

The results of sensor and electron-microscopic studies of the initial stages of cadmium telluride film formation through vapor deposition on a substrate at room temperature and on a substrate cooled by liquid nitrogen (highly nonequilibrium conditions) are reported. A piezoelectric quartz resonator is used as a sensor. The kinetic curves of the sensor analytical signal and photomicrographs are presented. A jumplike character of the nucleation process and a quasi-periodical growth mechanism for island films are disclosed. A sequence of new-phase island ensembles is formed in an analogous way. These islands increase the substrate surface coverage in a quasi-discrete manner. The experimental results are shown to agree with current theory of the first-order phase transitions and models of layer formation in highly nonequilibrium conditions.     

小型化行波管灯丝电源设计

综述了行波管灯丝基本工作过程及其对电源的特殊要求,分析了行波管灯丝负载基本特性,对灯丝电源设计的特殊性及问题进行了深入细致分析,通过对Topswitch系列控制芯片的性能特点分析,设计了以反激变换器为主电路的灯丝电源。根据灯丝启动特点及其对电源稳定性基本要求设计了高精度反馈电路与限流电路。通过Pspice仿真、样机实验及例行试验测试,验证了理论分析及设计的合理性与可行性,仿真与测试结果表明电源主电路、反馈电路及限流电路能够很好地满足行波管灯丝对电源的各项指标要求。     

Piezoelectric atomization of liquids with dynamic viscosities up to 175 cP at room temperature

Piezoelectric atomization has been applied in the field of respiratory medicine delivery and chemistry. However, the wider application of this technique is limited by the viscosity of the liquid. High-viscosity liquid atomization has great potential for applications in aerospace, medicine, solid-state batteries and engines, but the actual development of atomization is behind expectations. In this study, instead of the traditional model of single-dimensional vibration as a power supply, we propose a novel atomization mechanism that uses two coupled vibrations to induce micro-amplitude elliptical motion of the particles on the surface of the liquid carrier, which produces a similar effect as localized traveling waves to push the liquid forward and induce cavitation to achieve atomization. To achieve this, a flow tube internal cavitation atomizer (FTICA) consisting of a vibration source, a connecting block and a liquid carrier is designed. The prototype can atomize liquids with dynamic viscosities up to 175 cP at room temperature with a driving frequency of 507 kHz and a voltage of 85 V. The maximum atomization rate in the experiment is 56.35 mg/min, and the average atomized particle diameter is 10 µm. Vibration models for the three parts of the proposed FTICA are established, and the vibration characteristics and atomization mechanism of the prototype were verified using the vibration displacement measurement experiment and the spectroscopic experiment. This study offers new possibilities for transpulmonary inhalation therapy, engine fuel supply, solid-state battery processing and other areas where high-viscosity microparticle atomization is needed.     

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The main circuit topology, control hardware and control sequence of the cathode filament power supply for the HL-2A neutral beam heating system was introduced. Feedback control simulation of main circuit of filament power supply is carried out through MATLAB simulation software. It is found that the ripple factor is about 1%when the current is about 1000A, and the ripple coefficient increases to 3% when the current drops to 200A. Without the AC filter reactor in series L₁ and parallel harmonic filter LC in the low level control cabinet, the output current ripple coefficient becomes larger obviously. It shows that L₁ and LC not only absorb harmonic current, but also filter the chopper waveform after AC voltage regulation to make the output waveform smoother.     

HL-2A装置MW级中性束加热系统灯丝电源设计与仿真分析

介绍了HL-2A 装置中性束加热系统阴极灯丝电源的主电路拓扑结构、控制硬件及控制时序等。运用MATLAB 仿真软件对灯丝电源主回路进行了反馈控制仿真，发现电流在1000A 左右时，纹波约为1%，而电流降低至200A 时，纹波增大，约为3%。分别去掉低位控制柜内进线端的串联交流滤波电抗器L₁ 和并联LC 谐波滤波器进行仿真，结果显示输出电流纹波明显变大，说明L₁ 和LC 除了能够吸收谐波电流减少进入电网谐波的作用外，还能够对交流调压后的斩波波形进行一定的滤波作用，使得输出波形更加平滑。     

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EAST NBI束线综合测试台已研制完成并具备一台兆瓦级离子源测试运行的全套电源设备,包括离子源灯丝电源、弧电源、加速器电源、抑制极电源、偏转磁体电源及缓冲器电源等。介绍了EAST兆瓦级离子源进行起弧放电调试运行的方式,叙述了各套离子源电源系统的设计结构、技术特点及运行控制方式,分析了离子源电源系统稳定可靠运行需要解决的各个难点,给出了EAST束线样机进行高功率及长脉冲束引出测试运行的实验结果。     

石墨炉原子吸收光谱法测定土壤中高盐分样品的镉

研究了石墨炉原子吸收光谱仪测定土壤的高盐分样品中镉的适宜条件。经过试验,在高盐情况下,会产生严重的干扰,难于取得准确结果。而采用低温原子化,可消除干扰,提高灵敏度。同时,具有准确、简便的特点,保护和延长了石墨管的寿命,节约了生产成本。方法检出限为：0.003μg/L,相对标准偏差RSD%（n=12）为5.28。     

悬浮液进样自吸扣背景石墨炉原子吸收光谱法测定高纯氧化铝中铜、铁和钠含量

采用悬浮液-自吸扣背景石墨炉原子吸收法测定了高纯氧化铝中痕量元素铜、铁、钠含量.实验对灰化温度、原子化温度和自吸扣背景灯电流等石墨炉原子吸收工作条件等进行了优化,确定了最佳测定条件.样品测试采用标准水溶液进行校正,方法准确性采用氧化铝AKP-30在高温高压和浓硫酸密闭条件下溶解样品进样分析测定结果与文献报道的其他测定方...     

Influence of the temperature modulation of an incident flux on the properties of films of cadmium selenotellurides synthesized under sharply nonequilibrium conditions

Results of structural and electrical investigations of the films of cadmium selenotellurides synthesized by evaporation and condensation in vacuum under sharply nonequilibrium conditions are presented. The modulating effect of a nonuniform thermal field on the vapor phase flux has been revealed. The possibility of controlling the stoichiometry of the film composition with the use of a thermal field applied on the path of the thermal phase from the evaporator to the substrate has been demonstrated. Curves of condensation and temperature dependences of the conductivity, Hall coefficient, and Hall mobility are presented.     

HL-2A 装置 LHCD 系统灯丝电源远程控制的 一种新方法

为解决 HL-2A 装置低杂波电流驱动(LHCD)系统灯丝电源无法远程控制的问题,介绍了基于西门子 WinCC 监测系统的 HL-2A 装置 LHCD 系统灯丝电源 MSComm 串行通信系统的设计与实现。在 WinCC 图形编辑 器中直接调用 MSComm 控件,编写 VBS 全局脚本实现对串口的访问,解决了硬件组态过程中串行通讯操作被 WinCC 所限制的问题。采用了虚拟串口技术、工业以太网通讯技术、光纤隔离技术等,提高了 WinCC 组态串口 设备的灵活性。HL-2A 装置 LHCD 实验证明,在 HL-2A 装置放电的复杂电磁环境下,LHCD 灯丝电源 MSComm 串行通信系统运行稳定、功能完善。     

Application of experimental design for optimization of erbium determination by high-resolution continuum source electrothermal atomic absorption spectrometry using lanthanum as a chemical modifier

ABSTRACT

In this paper, lanthanum was used as a chemical modifier for the direct determination of erbium by high-resolution continuum source electrothermal atomic absorption spectrometry. A two-step experimental design was used for optimization, first a full factorial design was conducted for identification of significant factors, and then a central composite design was carried out for final optimization of the significant factors. The optimum parameters were obtained as follows: atomization temperature of 2500°C, pyrolysis temperature of 1600°C, and pyrolysis time of 10?s in the presence of lanthanum as a chemical modifier. Under optimum conditions, the characteristic mass, limit of detection, and limit of quantification were 29?pg, 0.71, and 2.4?µg?L^?1, respectively. The precision of the method, estimated as the relative standard deviation for 10 replicate measurements of 50?µg?L^?1 of erbium, was 1.8%. The optimized method was applied to determine erbium content in sediments and rock samples. The determined values of erbium in sediment certified reference materials were in satisfactory agreement with the certified values according to the t-test for a 95% confidence level.     

介质阻挡放电中单个新型放电丝放电特征和光谱测量

在放电间隙较大(d=3.8 mm)的介质阻挡放电(DBD)中,通过减小放电区域(S=1 cm×1 cm),首次观察到了单个新型放电丝。与其他实验小组所观察到的单个放电丝相比,该单个新型放电丝由体放电(VD)和沿面放电(SD)二部分构成,其放电稳定性和持续性极好。利用高速照相机和光谱仪,研究了单个新型放电丝在外加电压半周期单次放电中的放电特征和单个新型放电丝侧面放电柱不同位置的等离子体状态。在高速照相机不同曝光时间条件下拍摄得到了单个新型放电丝端面和侧面放电的瞬时照片,并对其外加电压半周期单次放电的放电特征与辉光放电进行了对比。利用发射光谱法,采集了单个新型放电丝侧面放电柱不同位置的氩原子763.26 nm(2P₆→1S₅)和772.13 nm(2P₂→1S₃)发射谱线,并通过两条谱线强度比法,估算出了相应的电子激发温度。实验结果得出：单个新型放电丝由体放电和沿面放电构成,且沿面放电在体放电四周呈枝状扩散;单个新型放电丝在外加电压半周期单次放电中与辉光放电特征相似,且在阴极呈现出漏斗状放电;氩原子谱线强度及其相应的电子激发温度从极板两端到中间均呈减小的变化趋势,表明单个新型放电丝侧面放电柱不同位置的等离子体状态不同。