A research on the effect of plasma spectrum collection device on LIBS spectral intensity

Only a small amount of spectral information is collected because the collection solid angle of the optical fiber probe and lens is very limited when collecting spectral information.To overcome this limitation,this study presents a novel method for acquiring plasma spectral information from various spatial directions.A parabolic-shaped plasma spectral collection device(PSCD)is employed to effectively collect more spectral information into the spectrometer,thereby enhancing the overall spectral intensity.The research objects in this study were soil samples containing different concentrations of heavy metals Pb,Cr,and Cd.The results indicate that the PSCD significantly enhances the spectral signal,with an enhancement rate of up to 45%.Moreover,the signal-to-noise ratio also increases by as much as 36%.Simultaneously,when compared to the absence of a device,it is found that there is no significant variation in plasma temperature when the PSCD is utilized.This observation eliminates the impact of the spatial effect caused by the PSCD on the spectral intensity.Consequently,a concentrationspectral intensity relationship curve is established under the PSCD.The results revealed that the linear fitting R^(2)for Pb,Cr,and Cd increased by 0.011,0.001,and 0.054,respectively.Additionally,the limit of detection(LOD)decreased by 0.361 ppm,0.901 ppm,and 0.602 ppm,respectively.These findings indicate that the spectral enhancement rate elevates with the increase in heavy metal concentration.Hence,the PSCD can effectively enhance the spectral intensity and reduce the detection limit of heavy metals in soil.

Measurement of the Plasma Rotation Velocity by Using Visible Spectrum on HL-1M Mokamak

The plasma rotation velocity were measured in HL-1M with Doppler shifts of CⅢ、 C Ⅱ、 O Ⅱ and H. line by a SKD high resolution spectrometer. The effects .of density' hydrogen pellet injection and carbon impurities injected by laser-blow-off on toroidal(V) and poloidal (Vθ)rotation velocity have been observed. The Vθ measured from H. line is only half of that from C Ⅱ impurity line.

Preliminary discussion on the ignition mechanism of exploding foil initiators igniting boron potassium nitrate

Exploding foil initiator(EFI)is a kind of advanced device for initiating explosives,but its function is unstable when it comes to directly igniting pyrotechnics.To solve the problem,this research aims to reveal the ignition mechanism of EFIs directly igniting pyrotechnics.An oscilloscope,a photon Doppler velocimetry,and a plasma spectrum measurement system were employed to obtain information of electric characteristics,impact pressure,and plasma temperature.The results of the electric characteristics and the impact pressure were inconsistent with ignition results.The only thing that the ignition success tests had in common was that their plasma all had a relatively long period of high-temperature duration(HTD).It eventually concludes that the ignition mechanism in this research is the microconvection heat transfer rather than the shock initiation,which differs from that of exploding foil initiators detonating explosives.Furthermore,the methods for evaluating the ignition success of semiconductor bridge initiators are not entirely applicable to the tests mentioned in this paper.The HTD is the critical parameter for judging the ignition success,and it is influenced by two factors:the late time discharge and the energy of the electric explosion.The longer time of the late time discharge and the more energy of the electric explosion,the easier it is to expand the HTD,which improves the probability of the ignition success.

Characteristics of emissive spectrum and the removal of nitric oxide in N_2/O_2/NO plasma with argon additive

Although the approach using non-thermal plasma（NTP） for deNOx has been studied for over 15 years,how to achieve higher removal effciency with lower cost is still a barrier for its industrial application.In order to investigate the impact of the argon additive on electron density,energy and nitric oxide reduction process in plasma,the spectrum of the dielectric barrier discharge at atmospheric pressure in a coaxial reactor was measured using the monochromater with high resolution.The comparative experiments for NO reduction were carried out simultaneously in N2/O2/NO plasma stream with and without argon,respectively.The nitrogen molecular spectrum which is attributed to the energy level transition（C^3πu→ B^3πg） was compared in the wavelength range 300-480 nm and the electron density and temperature were determined based on the relative intensities and Stark broadening width of spectral lines.The spectrum results indicated that the argon additive could enhance the intensity of emissive spectrum of plasma,thus the electron concentration as well as the energy was increased,and finally prompted the ionization rate to produce active N,O and O3.The results of NO reduction showed that NO conversion effciency increased in the range of 10%-30% with 5% addition of argon in stream comparing with the condition without argon additive.This study will play a positive role in the industrial application of dielectric barrier discharge deNOx reactor.

Continuous Emission Spectrum Measurement for Electron Temperature Determination in Low-Temperature Collisional Plasmas

Continuous emission spectrum measurement is applied for the inconvenient diagnos- tics of low-temperature collisional plasmas. According to the physical mechanism of continuous emission, a simplified model is presented to analyze the spectrum in low temperature plasma. The validity of this model is discussed in a wide range of discharge parameters, including electron tem- perature and ionization degree. Through the simplified model, the continuous emission spectrum in a collisional argon internal inductively coupled plasma is experimentally measured to determine the electron temperature distribution for different gas pressures and radio-frequency powers. The inverse Abel transform is also applied for a better spatially resoluted results. Meanwhile, the result of the continuous emission spectrum measurement is compared to that of the electrostatic double probes, which indicates the effectiveness of this method.

The Investigation Capability of Plasma Focus Device for 13N Radioisotope Production by Means of Deuteron Experimental Spectrum

Optimal condition for 13N radioisotope production through 12C (d,n) 13N within plasma focus device is investigated. As the deuteron spectrum follows the empirical power law of the form E-m, it is shown that the activity decreases by increasing the value of m. Unlike the fact that the repetition rate increases the activity, it is possible to achieve higher activities by increasing the bombardment time at a fixed repetition rate.

辅助放电下刷状空气等离子体羽的放电特性和参数诊断

大气压等离子体射流(APPJ)能产生富含活性粒子的等离子体羽,在众多领域具有广泛的应用前景.从应用角度考虑,如何产生大尺度弥散等离子体羽是APPJ研究的热点之一.目前,利用惰性气体APPJ已经能产生令人满意的大尺度等离子体羽,但从经济性上考虑,如何产生大尺度空气等离子体羽更具有应用价值.针对于此,本工作设计了一个具有辅助放电的APPJ,产生了大尺度刷形空气等离子体羽.结果表明,刷状空气等离子体羽可以在一定电压峰值(Vp)内产生,并且随着Vp增大等离子体羽的长度和发光强度都增大.电压和发光信号波形表明,每半个电压周期最多会有一次放电.每半个电压周期的放电概率和光脉冲的强度都随着Vp增大而增大,但放电起始时刻的电压值会随着Vp增大而降低.高速影像研究表明弥散刷形空气等离子体羽和小尺度空气等离子体羽的产生机制类似,均源于分叉正流光的时间叠加.此外,采集了刷形空气等离子体羽的发射光谱,并利用其对放电的电子温度、电子密度、分子振动温度和气体温度进行了研究.结果表明,等离子体羽的气体温度较低,且基本不随Vp变化.然而电子密度、电子温度和分子振动温度均随着Vp增大而升高.利用激光诱导荧光光谱技术研究了等离子体羽的OH浓度,发现OH分布较为均匀,且其浓度随着Vp增大而增大.最后,对这些变化规律进行定性分析.

电感耦合等离子体发射光谱(ICP-OES)法在地质样品测定中的研究进展

电感耦合等离子体发射光谱仪在地质样品中无机元素分析测试时是常用仪器,具有灵敏度高,干扰小,测定线性范围广、稳定性好等优点。对电感耦合等离子体发射光谱法测定地质土壤,岩石样品时采用的酸溶法、碱熔法、烧结法三种消解体系各自特点及消解剂的特性进行综述;详细分析了样品测定时外标法、内标法、标准加入法的选择及应用;探讨了样品测试时仪器条件的优化措施,同时分析了电感耦合等离子体发射光谱仪的干扰校正方法。最后,对电感耦合等离子体发射光谱测定技术在地质样品中非金属元素分析物测定的应用及未来发展进行了展望。

超快激光诱导等离子体成丝光谱

飞秒激光等离子体光丝大气中传输的独特物理过程在航天领域具有重要的应用前景。采用仿真与实验,验证了飞秒等离子体成丝的光谱展宽特征,获得了超快等离子体光丝在不同参数特征下,覆盖从可见到红外探测系统的波谱范围,及保持系统相对稳定的特征,对于借助强激光等离子体光丝光谱进行红外特征探测具有重要的启发作用。

同轴枪放电等离子体动力学与杂质谱特性

同轴枪放电可以产生高速度、高密度及高能量密度的等离子体射流,在等离子体空间推进、天体物理和高温核聚变等研究领域具有广泛的应用.基于同轴枪的实际应用,等离子体速度、密度、纯净度是评估等离子体特性的重要参量.本文通过对等离子体光电流信号和发射光谱的测量及放电图像的拍摄,研究了不同放电电流和气压对同轴枪放电等离子体的动力学特性、电子密度与杂质发射光谱的影响.实验结果表明:气压为10 Pa,放电电流为30—70 k A时,等离子体在枪内的加速时间随电流的增大而缩短,等离子体中阳极和阴极杂质光谱均随电流的增大而增强;放电电流为40 k A,气压为10—70 Pa时,等离子体加速时间随气压的增大而增长,等离子体中阴极杂质光谱强度随气压的增加不断降低,而阳极杂质光谱强度却是逐渐增加的,不过其增长速率逐渐减小.分析认为,不同放电电流和气压决定了等离子体获能、加速特性及电子密度,协同影响金属杂质特性.同轴枪喷口处发生等离子体箍缩效应与高密度电弧在枪内加速时间是影响阳极烧蚀的重要因素,阴极材料的杂质是离子轰击溅射产生的,主要依赖于离子携带的能量.

磁力搅拌-电感耦合等离子体发射光谱测定石灰性土壤中交换性盐基

以磁力搅拌提取、离心对土壤样品进行前处理,等离子体发射光谱法测定样品交换液中交换性钾、钠、钙、镁4项盐基。研究出一套适合批量农业土壤交换性盐基的测试方法,方法简便、高效节能、稳定、易于掌握。方法检出限为交换性钾0.025cmol/kg,交换性钠0.028cmol/kg,交换性钙0.040cmol/kg,交换性镁0.019cmol/kg;方法精密度的标准偏差(n=6)为1.46%~4.93%,均小于5%,国家有证标准物质的测定结果与推荐值一致,满足质控要求。

双向观测-电感耦合等离子体发射光谱法测定湿法炼锌浸出液中的多种元素

湿法炼锌浸出液中Zn、In、Fe、Cu、Cd、Mg、Co、Mn、As、Si、Sb、Ge元素的含量多采用滴定法、分光光度法、火焰原子吸收法、原子荧光法、示波极谱法等经典分析方法来测定,一般较难实现多元素同时分析,且存在分析流程长、操作繁琐、检测结果时效性差的弊端。本实验建立了样品不经预处理,在3%(V/V)的硝酸介质中,在仅仅只绘制两条校准曲线的情况下,充分利用双向观测-电感耦合等离子体发射光谱法(ICP-OES)径向观测线性范围宽、基体效应小的特点来测定湿法炼锌浸出液中浓度水平在0.50g/L~150g/L的Zn、Fe、Mg、Mn、Cu;利用该法轴向观测灵敏度高、检出限低的特点来测定湿法炼锌浸出液中浓度小于0.50g/L的In、Fe、Cu、Cd、Co、As、Si、Sb、Ge。该方法操作简单,分析结果时效性强,各元素的测定结果与滴定法、分光光度法、火焰原子吸收法、原子荧光法、示波极谱法测得值相符,该法各元素的检出限在0.0009μg/mL~0.079μg/mL之间,相对标准偏差在0.30%~1.81%之间,加标回收率均在90.0%~107.0%之间,能较好的应用于湿法炼锌浸出液中主元素及杂质元素的测定。

激光诱导击穿光谱技术在绝缘子污秽快速定量检测中的应用

为研究激光诱导击穿光谱技术在绝缘子污秽快速定量检测中的应用,提升绝缘子污秽检测精度与速度,本文搭建基于激光诱导击穿光谱技术的检测平台对人工污秽与自然污秽样本进行测试,其中人工污秽样本由NaCl、CaSO_(4)、CaCO_(3)与高岭土混合形成,自然污秽样本则取自南方某地区电网中运行2年与4年的硅橡胶绝缘子,借助自由定标激光诱导击穿光谱方法对绝缘子污秽进行快速定量检测。结果表明:两个人工污秽样本中存在不同比例的9种元素成分,而两个自然污秽样本则分别存在9种和11种不同的元素;经过自吸收校正后,绝缘子污秽元素在玻尔兹曼图中表现为分布点排列整齐、回归线斜率一致、拟合程度高以及各元素的谱线强度明显增强,有效降低了自吸收效应对绝缘子污秽快速定量检测的影响,使检测精度得到提升。

DTPA-CaCl_(2)-TEA浸取-电感耦合等离子体发射光谱法测定土壤中有效锌、锰、铁、铜

本文以DTPA-CaCl_(2)-TEA浸提剂提取土壤中有效态铜、锌、铁、锰,以电感耦合等离子体发射光谱(ICP-AES)进行测定。对不同的提取温度进行探究,确定最佳提取温度为25℃±2℃。对空白溶液平行测定6次,以3倍标准偏差计算出有效铜、锌、铁、锰的检出限依次为0.024mg/kg、0.024mg/kg、0.030mg/kg、0.147mg/kg,通过对国家标准土壤样品GBW 07461(ASA-10)、GBW 07414a(ASA-3a)、GBW07460(ASA-9)进行验证,其准确度与精密度均可满足分析要求。

超声消解ICP-AES测定铝合金中硅元素含量

建立了超声密闭消解-电感耦合等离子体发射光谱法测定铝合金中硅元素含量的分析方法。通过优化样品前处理条件,对超声强度、密闭条件、超声温度、超声时间及酸的浓度进行筛选,选择合适的分析谱线,测定了铝合金中等含量硅。对不同硅含量的铝合金ZLD105,ZBY5291,ZBY5091进行了精密度及准确度实验,其相对标准偏差(S_(RSD))在0.3%~0.7%,加标回收率在98.9%~101.0%。该方法分析成本低、快速、准确、方便,完全可应用于实际样品测试。

高能X射线光谱分析工具——SasalPy

等离子体模型是天文学家解析高能天体观测数据的重要工具,发展精确便利的等离子体模型有助于研究者高效的进行高能X射线光谱分析工作.在现有的SASAL等离子体模型的基础上进一步提出一种新的基于Python语言的高能X射线光谱分析工具包SasalPy,并从理论框架、功能性和差异性方面阐述SasalPy的可靠性和精确性.线辐射和连续辐射计算结果表明,原子参数如跃迁速率、碰撞强度等会对合成光谱产生明显地影响.以Capella星冕的体微分发射度为基础开展了三个温度的光谱合成应用,并通过与其他等离子体模型辐射损失结果的对比,说明SasalPy在X射线能段比较精确可靠.

Experimental investigation of laser-produced-plasma EUV source based on liquid target

A laser-produced plasma(LPP) source was built using liquid as target and a Nd:YAG laser as the irradiation laser, and the LPP source's radiation with ethanol and acetone target respectively was measured by an AXUV100 silicon photodiode combined with a McPHERSON model 247 grazing incidence monochromator of the resolution Δλ≤0.075 nm and the wavelength scanning interval 0.5 nm. Both ethanol and acetone target LPP source had EUV emission at 11～20 nm wavelength. The comparison between the spectra of the two kinds of target materials shows that all the two kinds of target source's spectra are the result of oxygen ions' transitions under current source's parameters, but the spectrum intensity from different target sources is different. The spectra intensity from the ethanol target is higher than that from the acetone target. In addition, the target liquid is forced into the vacuum chamber by the background pressure supported by the connected external high pressure gas, and the influence of the background pressure on the source's intensity is investigated.

液相色谱串联质谱法和化学发光微粒子免疫法测定人血清中卡马西平血药浓度的一致性评价

目的比较液相色谱串联质谱法(LC-MS/MS)与化学发光微粒子免疫法(CMIA)两种方法检测人血清中卡马西平浓度的一致性。方法收集118例临床血清样本,分别用LC-MS/MS和CMIA两种方法检测卡马西平。采用Passing-Boblok回归分析两种方法之间的相关性,采用Bland-Altman及Mountain plot评估两种方法的一致性,使用Kappa分析判断两种方法检测卡马西平浓度是否在有效范围的符合率。结果LCMS/MS与CMIA法检测卡马西平结果分别为(5.68±2.36)μg/mL和(6.45±2.69)μg/mL,Passing-Bablok回归分析显示两种方法检测卡马西平浓度的回归方程为yCMIA=-0.04885+1.1538xLC-MS/MS,斜率为1.1538(95%CI:1.0887~1.2244)不包含1,截距为-0.04885(95%CI:-0.4559~0.2792)包含0,P>0.1,线性度无明显偏差。Bland-Altman图显示两种方法差值的均值为-0.77,界外点数(比率)为5.08%;山形图的山顶值为-0.74μg/mL,偏离0较小,表明两种方法测量的结果一致性较好。两种方法判断卡马西平治疗浓度水平Kappa系数为0.693,诊断符合率为89.93%。结论CMIA与LC-MS/MS两个检测系统检测结果一致性较好。

Spatial and Excitation Variations for Different Applied Voltages in an Atmospheric Neon Plasma Jet

A neon plasma jet was generated in air, driven by a 9 kHz sinusoidal power supply. The characteristics of the plasma plume and the optical spectra with plasma propagation for different applied voltages were investigated. By increasing the applied voltage, the plasma plume first increases and then retracts to become short and bulky. The shortened effect of Ne plasma plume （about 10 mm） for the further voltage increasing is more apparent than that of He （about 3 mm） and Ar （about 1 mm）. Emission intensity of the N2 （337 am） increases with the applied voltage, gradually substituting the emission intensity of Ne （702 nm and 585 am） as the noticeable radiation. At the nozzle opening, the Ne （702 am） emission dominates, while the Ne （585 nm） emission is most noticeable around the tip of the plasma plume. The spatial distribution of the three spectral lines indicates that Ne （702 nm） emission decreases dramatically with plasma propagation while Ne （585 am） and N2 （337 nm） emissions reach their maxima at the middle of the plasma plume. The results indicate that the Ne （702 nm） emission is much more sensitive to the average electron temperature and the density of the high-energy electrons, so it changes greatly at the tube nozzle and little at the tip region as the voltage increases. The population of high-energy electrons, the average electron temperature, the collision with air molecules and the Penning effect between Ne metastables and air molecules may explain their different variations with plasma propagating and voltage increasing.

Electric and plasma characteristics of RF discharge plasma actuation under varying pressures

The electric and plasma characteristics of RF discharge plasma actuation under varying pressure have been inves- tigated experimentally. As the pressure increases, the shapes of charge-voltage Lissajous curves vary, and the discharge energy increases. The emission spectra show significant difference as the pressure varies. When the pressure is 1000 Pa, the electron temperature is estimated to be 4.139 eV, the electron density and the vibrational temperature of plasma are /peak /lPeak which describes the electron temper- 4.71 x 10^11 cm-3 and 1.27 eV, respectively. The ratio of spectral lines ＂391.4/＇380.5 ature hardly changes when the pressure varies between 5000-30000 Pa, while it increases remarkably with the pressure below 5000 Pa, indicating a transition from filamentary discharge to glow discharge. The characteristics of emission spec- trum are obviously influenced by the loading power. With more loading power, both of the illumination and emission spectrum intensity increase at 10000 Pa. The pin-pin electrode RF discharge is arc-like at power higher than 33 W, which results in a macroscopic air temperature increase.