Atmospheric pressure plasma jet utilizing Ar and Ar/H_2O mixtures and its applications to bacteria inactivation

An atmospheric pressure plasma jet generated with Ar with H2O vapor is characterized and applied to inactivation of Bacillus subtilis spores. The emission spectra obtained from Ar/H2O plasma shows a higher intensity of OH radicals compared to pure argon at a specified H2O concentration. The gas temperature is estimated by comparing the simulated spectra of the OH band with experimental spectra. The excitation electron temperature is determined from the Boltzmann’s plots and Stark broadening of the hydrogen Balmer Hβline is applied to measure the electron density. The gas temperature, excitation electron temperature, and electron density of the plasma jet decrease with the increase of water vapor concentration at a fixed input voltage. The bacteria inactivation rate increases with the increase of OH generation reaching a maximum reduction at 2.6%(v/v) water vapor. Our results also show that the OH radicals generated by the Ar/H2O plasma jet only makes a limited contribution to spore inactivation and the shape change of the spores before and after plasma irradiation is discussed.     

An Investigation of 4He+12C and 4He+16O Reactions Using the Cluster Model

The α -target semimicroscopic single folding potentials have been derived by folding a composite (repulsive and attractive) effective α-α interaction with the α -cluster distribution density in the target nuclei. The obtained potentials are considered as the real part of the nuclear optical model potentials, while the imaginary parts are phenomenologicaly expressed using the Woods-Saxon form. Nine sets of measured experimental data of the ⁴He+¹²C and ⁴He+¹⁶O elastic rainbow scattering over the energy range 80-240 MeV are analyzed using the obtained potentials. The data are successfully reproduced using the extracted potentials. The resulted reaction cross sections are also investigated and compared with the available corresponding data.     

Spectroscopic investigation of the plasma of a high-current diffuse discharge in He/Ar/CF2Cl2(CCl4) mixtures

Survey emission spectra in the region of 190–600 nm and time and service-life characteristics of a transverse nanosecond discharge in He/Ar/CF₂Cl₂(CCl₄) mixtures at a pressure of 10–100 kPa are investigated. In the emission spectra, excited products of the decomposition of freons—C₂(A−X), CN(B−X), Cl ₂ ^* , C^*, Cl^*, and Cl^+*— and the emission of ArF at λ=193 nm are revealed. The emissions of Cl ₂ ^* at λ=258 nm and ArF at λ=193 nm were the most intense. The discharge in the He/Ar/CF₂Cl₂ mixture is a multiwave emission source with λ=258 nm Cl ₂ ^* 193 nm ArF, and probably, 175 nm Arcl. It is of interest for applications in UV-VUV-range pulse photometry. The duration of the emission on Cl ₂ ^* , ArF, ArI, ClI, and ClII transitions in the discharge in the Ar/CF₂Cl₂ mixture (P=10–20 kPa) was 200–300 nsec. With adding He and increasing pressure to 100 kPa the duration of the emission decreased by a factor of 1.5–2. The basic mechanisms of the formation of Cl₂, ArF, and CN(B) molecules in the transverse-discharge plasma are considered. Uzhgorod State University, 46, Pidgirna Str., Uzhgorod, 294000, Ukraine. Translated from Zhurnal. Prikladnoi Spektroskopii, Vol. 66, No. 2, pp. 241–246, March–April, 1999.     

锗酸锌锰荧光体发光学与荧光瞬态衰减研究

制备一系列锗酸锌锰荧光体,并探讨其发光特性、瞬态荧光衰减与色度值与所掺杂锰离子含量之间的相互关系.本系列荧光体锰离子发射峰波长,随Mn²⁺含量由0增加0.05,由527nm红移至534nm.实验表明这可能与Mn²⁺所占据的四面体格位,遭扭曲而导致晶场强度变弱有关.本系列荧光体的CIE色度坐标值,则随所掺杂Mn²⁺含量,仅有微小改变.锗酸锌锰荧光体瞬态荧光衰减的研究结果表明:锗酸锌基质的衰减生命期在纳秒范围;随Mn²⁺掺杂量增加,在毫秒范围的锰离子荧光衰减生命期逐渐缩短.此现象可能与Mn²⁺-Mn²⁺离子对中,Mn²⁺的自旋交换相互作用有密切关系.     

Fabricating GeO_2 passivation layer by N_2O plasma oxidation for Ge NMOSFETs application

In this paper, oxidation of Ge surface by N2O plasma is presented and experimentally demonstrated. Results show that1.0-nm GeO2is achieved after 120-s N2O plasma oxidation at 300?C. The GeO2/Ge interface is atomically smooth. The interface state density of Ge surface after N2O plasma passivation is about ～ 3 × 1011cm-2·eV-1. With GeO2passivation,the hysteresis of metal–oxide–semiconductor(MOS) capacitor with Al2O3serving as gate dielectric is reduced to ～ 50 mV,compared with ～ 130 mV of the untreated one. The Fermi-level at GeO2/Ge interface is unpinned, and the surface potential is effectively modulated by the gate voltage.     

Experimental study on parameters of dust plasma in SiH4/C2H4/Ar discharges

Measurements of dust plasma parameters were carried out in the discharges of （SiH4/C2H4/Ar） mixtures. Dust particles were formed in the capacitively coupled radio-frequency discharge of these reactive mixtures in a cylindrical chamber. Langmuir probe was employed for diagnosing and measuring the important plasma parameters such as electron density and electron temperature. The results showed that the electron density dropped, and in contrast the electron temperature rose when the dust particles formed. The curves of the electron density and temperature versus the RF power and pressure were presented and analysed. Further, it was found that the wriations of electron temperature and the size of dust void with the RF power followed the similar trends. These trends might be useful for understanding more about the characteristics of dusty voids.     

CH4/H2和CH4/He体系等离子体发射光谱分析

 在CH₄/H₂和CH₄/He和CH₄/He两种系统中,利用光学发射谱技术对螺旋波放电产生低压甲烷等离子体内活性粒子的光学发射特征进行了原位诊断。在实验中,两种体系下同时都测得的主要荷电粒子为CH,Ha,Hb,Hg以及H2等。研究了各实验参数对这些活性粒子CH, Ha,Hb以及Hg的发射光谱强度的影响。结果表明：在CH₄/H₂体系下,随着射频功率的增大,Ha,Hb,Hg以及CH基团的相对强度都随着增加,而当放电气压变化时它们都呈现先增大而后减小的趋势。在CH₄/He体系下,随射频功率的增加,Ha,Hb,Hg以及CH相对强度变化的总体趋势也都是先增加而后减小,当工作气压增加时,Ha,Hb以及Hg的相对强度变化也是呈现先增大而后减小,但CH基团的相对强度却是逐渐减小的;这些结果为等离子体沉积各种薄膜过程的理解及制备工艺参数的调整提供了参考。     

Emission Mössbauer studies of 57Co2+ and 119Sb5+ adsorbed on γ-Fe2O3 and NiFe2O4 surfaces

Summary Surface chemical states of⁵⁷Co²⁺ and¹¹⁹Sb⁵⁺ ions adsorbed on γ-Fe₂O₃ and NiFe₂O₄ were studied in the presence of the aqueous phase using the magnetic interaction between the substrates and⁵⁷Fe²⁺ or¹¹⁹Sn⁴⁺ arising from the adsorbed species. Two chemical forms were observed for the⁵⁷Co²⁺ adsorbed on γ-Fe₂O₃; one giving a peak in the high-field region and another giving a broad distribution in the lower fields, which were attributed to⁵⁷Co²⁺ at surfaceB sites of the spinel structure of γ-Fe₂O₃ and⁵⁷Co²⁺ species weakly bonded to the substrate, respectively. In case of the NiFe₂O₄ substrate, the latter species was dominant and was converted to the former by heating. Most of the¹¹⁹Sb⁵⁺ ions adsorbed on the γ-Fe₂O₃ and NiFe₂O₄ particles were found to have a certain magnetic interaction with the magnetically ordered ions of the substrates. Paper presented at the ICAME-95, Rimini, 10–16, September 1995     

Luminescence spectroscopy of Eu3+ and Mn2+ ions in MgGa2O4 spinel

Photoluminescence and excitation spectra of the spinel-type MgGa₂O₄ with 0.5 mol. % Mn²⁺ ions and Eu³⁺ content from 0 to 8 mol. % have been investigated in this work at room temperature. Polycrystalline samples were synthesized via high-temperature solid-state reaction method. Photoluminescence spectra of all samples exhibit host emission presented by a broad “blue” band peaking ∼430 nm, which consists of at least three elementary bands that correspond to different host defects. Excitation of the host luminescence showed the broad band with a maximum at 360 nm. Characteristic bands of d–d transitions of Mn²⁺ ions and f–f transitions of Eu³⁺ ions together with charge-transfer bands (CTB) of these ions were also found on the excitation spectra. Mn²⁺ and Eu³⁺ co-doped samples emit in green and red spectral regions. Mn²⁺ ions are responsible for the green emission band at 505 nm (⁴Т₁→⁶А₁ transition). The studies of photoluminescence spectra of activated samples with different Eu³⁺ ions content show characteristic f–f luminesecence of Eu³⁺ ions. The maximum of Eu³⁺ emission was found at 618 nm (⁵D₀→⁷F₂) and optimal concentration of activator ions was around 4 mol. %.     

An Investigation of ~4He+~(12)C and ~4He+~(16)O Reactions Using the Cluster Model

The α-target semimicroscopic single folding potentials have been derived by folding a composite (repul-sive and attractive) effective α-α interaction with the α-cluster distribution density in the target nuclei. The obtained potentials are considered as the real part of the nuclear optical model potentials, while the imaginary parts are phe-nomenologicaly expressed using the Woods-Saxon form. Nine sets of measured experimental data of the 4He+12C and 4 He+16O elastic rainbow scattering over the energy range 80-240 MeV are analyzed using the obtained potentials. The data are successfully reproduced using the extracted potentials. The resulted reaction cross sections are also investigated and compared with the available corresponding data.     

30MeV/u 40 Ar+112,124Sn反应后角能谱温度的同位旋效应

在30MeV/u^40Ar 112,124Sn反应中用平行板雪崩计数器实现了前冲余核的测量，在不同的线性动量转移下用运动源模型拟合了后角的3He,α和^6He能谱，发现^3He的能谱斜率温度在^124Sn系统中高于^112Sn系数，而^6He的温度在^112Sn系统中更高，a粒子在两个系统中没有明显差别，用热核粒子蒸发过程衰变道的选择对这种同位旋相关性进行了解释，GEMINI的计算不能重视实验结果。     

30MeV/u 40Ar+112,124Sn反应中的同位素产额比与核温度

系统研究了30MeV/u^40Ar ^112,124Sn反应中的轻粒子同位素产额比随角度和初始激发能的变化关系,对于两个反应体系,均观察到3He/^4He和^6Ni/^7Li的产额比随角度的增加而增加,^6He/^4He和^8Li/^7Li随角度的增加而减少,统计发射的运动学效应不能完全符合实验结果,各种单同位素产额比与靶核的N／Z比有关,表现出同位旋效应,而由双同位素比提取的核温度几乎没有靶核相关性。     

SrAl2O4：Eu2+的长余辉发光特性的研究

本文研究了SrAl2O4:Eu2+材料的发光及长余辉特性.首次得到了这一材料的发光衰减由初始的快衰减和后期的慢衰减过程所组成,以及热释发光光谱出现两个热释发光峰值的实验结果.对所得结果进行了分析讨论,提出了这一材料的发光衰减是由两个足够深的电子陷阱所引起.     

Eu3+摩尔浓度对Y2O2S:Eu3+,Mg2+,Ti4+红色长余辉材料光谱的影响

用高温固相法制备了Y2O2S：Eu^3 ,Mg^2 ,Ti^4 红色长余辉材料。测量了该材料的余辉曲线,余辉时间为1h以上;由X射线衍射得到晶体结构为Y2O2S.测量了不同Eu^3 摩尔浓度下的激发光谱和发射光谱,得到从^5DJ(J=0,1,2,3)^-7FJ(J=0,1,2,3,4,5)的发射谱线,并得到位于260,345,468和540nm激发峰。由于激活剂饱和效应,Y2O2S：Eu^3 ,Mg^2 ,Ti^4 发射光谱中513．6,540．1,556．4,587．3和589．3nm属于从^5D2,^5D1到^7FJ(J=0,1,2,3,4)跃迁的发射峰随Eu^3 摩尔浓度的增加相对削弱;激发谱包括位于350nm左右属于电荷转移态吸收(Eu^3 -O^2-,Eu^3 -S^2 )的激发主峰和在可见光区位于468,520和540nm属于Eu^3 离子4f-4厂吸收的激发峰。随着Eu^3 摩尔浓度的增加,位于468,520和540nm的激发峰相对增强。     

Influence of Negative Ions on Drift Waves in a Low‐Density Ar/O2‐Plasma

The effect of negative ions on the drift wave instability has been studied in detail in a linear device by means of Langmuir probes and cross‐correlation analysis. Drift waves are excited in low‐density (5 × 10¹⁴ m^–3) and strongly magnetized (0.5 T) pure argon plasmas and in the presence of an oxygen admixture. The radial density profile of negative ions is hollow. For increasing concentration of negative ions the wave frequency decreases by about 25%. Despite of an axial density gradient, a global wave frequency is established for the entire column length. While for the noble gas case the drift wave frequency is given by the equilibrium plasma parameters in the mid‐plane, there is no such relationship for the argon plasma with oxygen admixture. This different finding is attributed to the inhomogeneous distribution of the negative ions (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Electron Temperature Dependence of the Dissociative Recombination Coefficient of Molecular Argon Ions Ar+2 with Electrons

A dual mode (TM₀₁₀ cylindrical cavity/cylindrical waveguide) microwave apparatus is used to study the ion mobility and dissociative recombination of molecular argon ions with electrons in the afterglow period of a d.c. glow discharge as a function of electron temperature when electrons were heated by microwaves up to T_e ≤ 10300K, with T₊ = T_gas = 300K. The electron temperature dependence of the total rate coefficient of dissociative recombination may be represented by α (Ar⁺₂) = (8.1 ± 0.5) × 10^–7[300/T_e(inK)]^0.64cm³s^–1 which is in very good agreement with most previous experimental results but not with the recent theoretical calculations (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Zn2 GeO4:Mn2+绿色磷光粉的制备和长余辉性能

采用高温固相反应法合成了Zn_2GeO_4∶xMn~(2+)系列绿色长余辉磷光粉。XRD分析结果表明,掺锰磷光粉的主要衍射峰位与锗酸锌晶体标准卡基本一致,但略有红移。SEM照片显示,相对于Zn_2GeO_4基质平均粒径而言,掺锰磷光粉的颗粒尺寸均增大。在325 nm紫外光激发下,Zn_2GeO_4∶Mn~(2+)发射出强的530 nm绿光,优化掺锰离子浓度为0.5%。同时发现Zn_2GeO_4∶0.2Mn~(2+)磷光粉暗场条件下的余辉时间超过180 min,详细讨论了Zn_2GeO_4∶Mn~(2+)长余辉发光的内在机理。     

35MeV/u 40 Ar+197 Au反应中热核的碎裂密度

许多提取核反应过程中熵产生的方法只适用于高能核反应过程 ,而约化d的产额方法可以用于较低能量的重离子核反应中 .对于 3 5MeV/u40 Ar+ 197Au的核反应过程 ,利用这种方法所得的熵和约化带电粒子多重性提取的熵结果一致 .对于后角热核发射体系 ,实验提取的核温度为 ( 4.7± 1 .2 )MeV ,熵为S/A =2 .5± 0 .5,根据实验提取的熵和核温度可以确定其碎裂密度小于 0 .1 ρ0     

30MeV/u 40Ar+ 112,124Sn反应中态布居核温度的同位旋效应

用13单元望远镜探测器阵列测量了30MeV/u ⁴⁰Ar +^112,124Sn反应中小角关联粒子,由两体符合事件提取了αα关联函数.用三体弹道理论模型MENEKA计算本底关联函数,用Monte Carlo方法计算探测效率函数,在扣除本底产额并考虑探测效率的修正后,对不同同位旋反应系统⁴⁰Ar +¹¹²Sn和⁴⁰Ar+¹²⁴Sn提取的相对态布居核温度分别是4.18±0.25 0.21MeV和4.10±0.22 0.20MeV ;考察态布居核温度和粒子能量的关系时,观察到两个系统的发射温度均随着粒子能量的增加而降低,缺中子系统⁴⁰Ar +¹¹²Sn中由低能时的5.13±0.30 0.2 6MeV降低到高能时的3.87±0.37 0.29MeV ,丰中子系统⁴⁰Ar+¹²⁴Sn中由低能时的5.39±0.30 0.26MeV降低到高能时的3.32±0.28 0.23MeV .用激发热核衰变过程的同位旋选择性对这种同位旋相关性进行了解释.     

基频光辐照靶产生的3ω0/2光谱与散射角的关系

用六条光纤组成的光纤阵列配光学多道分析仪，发展了一种多角度光谱分辨的诊断技术（MASRS）。用多角度谱分辨的散射光探测系统系统在6个角度对1.053μm激光CH平面靶产生的3ω0/2散射光谱进行了研究，实验显示散射光谱红移峰的峰位移动量和峰宽度与散射角度有较强的依赖关系，实验结果与理论模型计算的结果进行了比较，并由此估计了碳氢等离子体的电子温度约为0.55keV。