Diagnostics of Argon Inductively Coupled Plasma and Dielectric Barrier Discharge Plasma by Optical Emission Spectroscopy

An experimental setup was built up to carry out radio frequency (RF) inductively coupled plasma (ICP) and dielectric barrier discharge (DBD), and to depict the optical emission spectra (OES) of the discharges. OES from argon ICP and DBD plasmas in visible and near ultraviolet region were measured. For argon ICP, the higher RF power input (higher than 500 W for our machine), the higher degree of argon plasma ionization. But that doesn't mean a higher mean electron energy. With the increase in the power input, the mean electron energy increases slightly, whereas the density of electron increases apparently On the contrary, argon DBD discharge behaves in the manner of a pulsed DC discharge on optical emission spectroscopy and V-I characteristics. DBD current is composed of a series of pulses equally spaced in temporal domain. The Kinetics of DBD emission strength is mainly governed by the frequency of the current pulse.

A Study on the Determination of Copper by Microwave Induced Plasma Atomic Emission Spectrometry (MIP-AES)

The determination of copper by MIP-AES was investigated in detail. Aqueous samples were introduced from an ultrasonic nebulizer and the solvent was removed by a desolvation device before introduction of the aerosol into the MIP. The desolvation system consisted of a condenser associated with a concentrated H2SO4 absorption cell. Various experimental conditions and interferences from easily ionised elements (EIEs) were also studied and some practical samples were analyzed.

OH and O radicals production in atmospheric pressure air/Ar/H_2O gliding arc discharge plasma jet

Atmospheric pressure air/Ar/H_2O gliding arc discharge plasma is produced by a pulsed dc power supply. An optical emission spectroscopic（OES） diagnostic technique is used for the characterization of plasmas and for identifications of OH and O radicals along with other species in the plasmas. The OES diagnostic technique reveals the excitation Tx？≈？5550–9000 K, rotational Tr？≈？1350–2700 K and gas Tg？≈？850–1600 K temperatures, and electron density n？（1.1-1.9） ′101 4 cm^（-3） e under different experimental conditions. The production and destruction of OH and O radicals are investigated as functions of applied voltage and air flow rate. Relative intensities of OH and O radicals indicate that their production rates are increased with increasing Ar content in the gas mixture and applied voltage. nereveals that the higher densities of OH and O radicals are produced in the discharge due to more effective electron impact dissociation of H_2O and O_2 molecules caused by higher kinetic energies as gained by electrons from the enhanced electric field as well as by enhanced n e.The productions of OH and O are decreasing with increasing air flow rate due to removal of Joule heat from the discharge region but enhanced air flow rate significantly modifies discharge maintenance properties. Besides, Tgsignificantly reduces with the enhanced air flow rate. This investigation reveals that Ar plays a significant role in the production of OH and O radicals.

Understanding hydrogen plasma processes based on the diagnostic results of 2.45 GHz ECRIS at Peking University

Optical emission spectroscopy（OES）, as a simple in situ method without disturbing the plasma, has been performed for the plasma diagnosis of a 2.45 GHz permanent magnet electron cyclotron resonance（PMECR） ion source at Peking University（PKU）. A spectrum measurement platform has been set up with the quartz-chamber electron cyclotron resonance（ECR） ion source [Patent Number： ZL 201110026605.4] and experiments were carried out recently. The electron temperature and electron density inside the ECR plasma chamber have been measured with the method of line intensity ratio of noble gas. Hydrogen plasma processes inside the discharge chamber are discussed based on the diagnostic results. What is more, the superiority of the method of line intensity ratio of noble gas is indicated with a comparison to line intensity ratio of hydrogen. Details will be presented in this paper.

Tomography of a simply magnetized toroidal plasma

Optical emission spectroscopy is a passive diagnostic technique,which does not perturb the plasma state.In particular,in a hydrogen plasma,Balmer-alpha（Hα） emission can be easily measured in the visible range along a line of sight from outside the plasma vessel.Other emission lines in the visible spectral range from hydrogen atoms and molecules can be exploited too,in order to gather complementary pieces of information on the plasma state.Tomography allows us to capture bi-dimensional structures.We propose to adopt an emission spectroscopy tomography for studying the transverse profiles of magnetized plasmas when Abel inversion is not exploitable.An experimental campaign was carried out at the Thorello device,a simple magnetized torus.The characteristics of the profile extraction method,which we implemented for this purpose are discussed,together with a few results concerning the plasma profiles in a simply magnetized torus configuration.

Elemental Content in Brown Rice by Inductively Coupled Plasma Atomic Emission Spectroscopy Reveals the Evolution of Asian Cultivated Rice

The phylogenetic relationship for classification traits and eight mineral elements in brown rice （Oryza sativa L.） from Yunnan Province in China was carried out using microwave assisted digestion followed by inductively coupled plasma atomic emission spectroscopy, and the analytical procedures were carefully controlled and validated. In general, the results show that the mean levels of K, Ca, Mg, Fe and Cu in brown rice for 789 accessions of rice landraces was distinctly lower than that of improved cultivars. They further demonstrate that Ca plays an important role in the differentiation of subspecies indica-japonica, especially to enhance adaptation of cold stress, and that five mineral elements in brown rice enhance the eurytopicity from landrace to improved cultivar. Hierarchical cluster analysis, using average linkage from SPSS software based on eight mineral elements in brown rice, showed that Yunnan rice could be grouped into rice landrace and improved cultivar, with the rice landrace being further clustered into five subgroups, and that, interestingly, purple rice does not cluster with either of the groups. Our present data confirm that indica is the closest relative of late rice and white rice, and that they constitute rice landraces together, whereas japonica is the closest relatives of non-nuda, early-mid and glutinous rice. It is further shown that japonica, non-nuda, early-mid, glutinous, white and red rice might be more primitive than indica, nuda, late, non-glutinous and purple rice, respectively.

Application and Development Trends of Spectral Analysis in Draft of Non-Ferrous Metal Standards in China

Spectral analysis was a method of identifying substances, determining their chemical composition and calculating their content based on their spectral characteristics. This paper mainly discussed the application of various spectroscopic techniques, mainly including atomic absorption spectrometry (AAS) inductively coupled plasma emission spectrometry (ICP-AES) X-ray fluorescence spectroscopy (XRF) atomic fluorescence spectroscopy (AFS) direct reading spectroscopy (OES) glow discharge emission spectroscopy (GD-OSE) laser-induced breakdown spectroscopy (LIBS), in the formulation of non-ferrous metal standards in China. The AAS method was the most widely used single-element microanalysis method among the non-ferrous metal standards. The ICP-AES method was good at significant advantages in the simultaneous detection of multiple elements. The XRF method was increasingly used in the determination of primary and secondary trace elements due to its simple sample preparation and high efficiency. The AFS was mostly detected by single-element trace analysis. OES GD-OES and LIBS were playing an increasingly important role in the new demand area for non-ferrous metals. This paper discussed matrix elimination, sample digestion, sample preparation, instrument categories and other aspects of some standards, and summarized the advantages of spectral analysis and traditional chemical analysis methods. The new methods of future spectroscopic technology had been illustrated in the process of developing non-ferrous metal standards.

Dissolution properties of calcined gangue

To study the dissolution mechanism of gangue, dissolution characteristics of the gangue samples calcined at different temperatures in alkaline solutions and alkali metal silicate solutions with respect to Si and Al ions were analyzed by identical coupled plasma optical emission spectroscopy （ICP）. The results show that the extent of dissolution of Al and Si varies with calcination temperature. It shows that the samples have a higher degree of dissolution in NaOH than in KOH medium. Si and Al appear to have synchro-dissolution behavior in alkaline solution, which means that Si and Al could dissolve from the mineral surface in certain linked forms. The result that a higher degree of dissolution exists in sodium silicate solution and a lower degree of dissolution exists in sodium-potassium silicate solution of Al is proved by the 29Si NMR spectra and the mean connectivity degree of these alkali metal silicate solutions.

Study of Direct Determination of Trace Lanthanum in Biological Samples by ICP-AES Combined with Fluorination Electrothermal Vaporization Technique

A new method for direct determination of lanthanum in solid biological materials by fluorination electrothermal vaporization ICP-AES technique with polytetrafluoroethylene(PTFE) disperser as a fluorination agent has been described. The effect of particle size on the signal intensity of La has been investigated. The vaporization behaviour of lanthanum and the main factors affecting fluorinating vaporization have been observed.Under optimum experimental conditions,the detection limit of La to this method is 2.0 ng/ml,and the RSD is 4.5%.The proposed method has been applied to determining directly trace lanthanum in solid biological standard reference materials without any chemical pretreatment,and the determined values are in good agreement with the certified ones.

Determination and Multidimensional Analysis of 29 Inorganic Elements in Cardamine tangutorum O.E.Schulz of Different Origins

[Objectives]This study aimed to determine the contents of inorganic elements in Cardamine tangutorum O.E.Schulz samples from different origins to provide a scientific reference for the quality control,safety evaluation and clinical medicinal use of C.tangutorum O.E.Schulz.[Methods]The contents of Al,As,B,Ba,Ca,Cd,Co,Cr,Cu,Fe,Hg,K,Mg,Mn,Mo,Na,Ni,P,Pb,Pd,Rb,Se,Si,Sn,Sr,Ti,Tl,V and Zn in the C.tangutorum O.E.Schulz samples were determined simultaneously by wet digestion and inductively coupled plasma optical emission spectroscopy(ICP-OES),and the determination results were analyzed by principal component analysis.[Results]A total of 28 inorganic elements were detected in the samples of C.tangutorum O.E.Schulz from different origins.The contents of heavy metals did not exceed the limits.Among the elements,the determined values of Hg in all samples were below the detection limit,so it was not detected.The contents of Ca,Al,P and Fe were relatively high,and they were essential nutrients in the human body.There were significant differences among different elements.Samples from different origins show similar patterns in the distribution of main elements.Correlation analysis shows that 15 pairs of inorganic elements out of 24 elements had extremely significant positive correlations,and 26 pairs of elements had significant positive correlations.The principal component analysis determined Al,As,Ba,Ca,Cd,Fe,Mn,Ni,P,Pb,Pd,Se,V and Zn were the characteristic inorganic elements in the samples of C.tangutorum O.E.Schulz.[Conclusions]The contents of toxic heavy metals in C.tangutorum O.E.Schulz samples from different origins met the edible requirements.The method was simple,rapid and accurate,and could be used to analyze and determine the inorganic elements in the samples of C.tangutorum O.E.Schulz,providing a theoretical basis for the better development and utilization of C.tangutorum O.E.Schulz.

Plasma parameter diagnosis using hydrogen emission spectra of a quartz-chamber 2.45 GHz ECRIS at Peking University

A quartz-chamber 2.45 GHz electron cyclotron resonance ion source(ECRIS) was designed for diagnostic purposes at Peking University [Patent Number: ZL 201110026605.4]. This ion source can produce a maximum 84 m A hydrogen ion beam at 50 k V with a duty factor of 10%. The root-mean-square(RMS) emittance of this beam is less than 0.12π mm mrad. In our initial work,the electron temperature and electron density inside the plasma chamber had been measured with the line intensity ratio of noble gases. Based on these results, the atomic and molecular emission spectra of hydrogen were applied to determine the dissociation degree of hydrogen and the vibrational temperature of hydrogen molecules in the ground state, respectively. Measurements were performed at gas pressures from 4×10^(-4) to 1×10^(-3) Pa and at input peak RF power ranging from 1000 to 1800 W. The dissociation degree of hydrogen in the range of 0.5%-10% and the vibrational temperature of hydrogen molecules in the ground state in the range of 3500-8500 K were obtained. The plasma processes inside this ECRIS chamber were discussed based on these results.