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[IEEE 2018 28th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV) - Greifswald (2018.9.23-2018.9.28)] 2018 28th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV) - A Novel Method to Generate Multicomponent Metal Ions by Anodic and Cathodic Vacuum Arc Plasmas with Pure Electrodes
摘要： Usually multicomponent ions are generated from cathodic vacuum arc plasma with compound cathodes. In this paper, a novel method to produce multicomponent ions by simultaneous anodic and cathodic vacuum arc plasmas with pure electrodes has been studied. The vacuum arc discharge has been operated with Al anode and W cathode. To characterize the plasma plume generation, a combination of high-speed camera and time-of-flight mass spectrometer has been used to measure the spot phenomenon and multicomponent ions, respectively. Luminous spots have been simultaneously found on the anode and cathode to produce multicomponent ions, which has been verified by the examination of electrode erosion using SEM. The ion charge state distribution and multicomponent ions have also been measured. For comparison, the characteristic of vacuum arc discharge operated with the exchange of electrodes has been studied, which exhibits obvious discrepancies. This behavior of vacuum arc is considered to be controlled by the difference of cohesive energy, because the heat flow to the electrodes is sufficient to evaporate the electrode, and the ionization process by the plasma occurs in the nonequilibrium layers near the evaporated surface in cathode and anode regions. This interesting result is proposed to use for the synthesis of compound films.
关键词： cohesive energy,vacuum arc,multicomponent ions
更新于2025-09-23 15:23:52
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Preparation of multicomponent thin films by magnetron co-sputtering method: The Cu-Ti case study
摘要： The paper discusses the preparation of multicomponent thin films of Cu-Ti composite with desired elemental composition using the pulsed magnetron co-sputtering technology. The technological goal described in the paper was deposition the Cu-Ti composite with elemental ratio of about 50/50 at.%, which is close to the eutectic point from the Cu-Ti alloy system. A large difference in the sputtering yield (about seven-fold) of Cu and Ti metals was challenging, because of the features of used power supplies. Desired concentrations of the Ti and Cu elements were obtained as a result of application of multimagnetron sputtering system, where magnetrons were equipped with the Ti or Cu targets. Additionally, pulse power supply was used together with the pulse width modulation controller. Moreover, the article presents investigations of structural and mechanical properties of deposited Cu, Ti and Cu-Ti films with elemental composition of ca. 50/50 at.%. It was found that the two component Cu0.5Ti0.5 thin films were composed of Cu4Ti3 nanocrystallites built-in an amorphous matrix. As compared to the pure Cu and Ti thin films, the prepared composite exhibited improved hardness and better elasticity reflected in lower values of the Young’s modulus. The results of nanoindentation investigations showed that the Cu0.5Ti0.5 composite thin film was characterized by the hardness of 7.59 GPa.
关键词： thin film,CuTi alloy,multicomponent coating,magnetron sputtering
更新于2025-09-23 15:23:52
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Some important notes on ASTA software: A new method of analysis of simple and complex emission and absorption spectral lines
摘要： ASTA is a new spectral analysis software aiming to serve the growing need of an integrated computing environment which will implement efficiently the demanding process of multicomponent analysis. It is a cutting-edge spectral multicomponent analysis software for displaying, fitting and analyzing astronomical spectra of complex emission and absorption line profiles. Equipped with statistical and verification tools it accelerates complex mathematical precision checks and confirms the uniqueness of the calculated physical parameters and the number of the absorption components that construct every Broad Absorption/Emission Line (BAL/BEL) and Discrete Absorption Components (DACs). DACs (in the case of Hot Emission Stars) and BALs/BELs (in the case of Quasars) are spectral lines of the same ion and the same wavelength as the main spectral line, shifted at different ?λ, as they are created in different density regions which rotate and move radially with different velocities. The currently accepted view is that BELs, BALs and DACs may be due to a flow of many individual density enhancements, called clouds, cloudlets or clumps which are optically thick and very small compared with the size of the central continuum source. These density enhancements are not preexisting entities but are formed inside an unstable and turbulent wind and they are indicated by very complex profiles. According to this phenomenon, a prevailing view is that they are not simple absorption/emission lines, but the synthesis of a group of classical absorption line components of the same spectral line. ASTA software equipped with a multicomponent analysis model is a novel approach to curve fit these complex lines focusing on the physical representation of the calculated parameters of each of these components. The BAL Quasar SDSS J114548.38+393746.6 case study is analyzed to demonstrate the potential of ASTA, whereas the Quasar SDSS J000027.01+030715.5 narrow absorption line highlights the flexibility to analyze effectively simple spectral profiles.
关键词： Hot emission stars,BALs and BELs,Multicomponent analysis,Stellar spectroscopy,DACs,Quasars
更新于2025-09-23 15:22:29
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Prospective scintillation electron detectors for S(T)EM based on garnet film scintillators
摘要： The performance of a scintillation electron detector for a scanning electron microscope and/or a scanning transmission electron microscope (S(T)EM) based on new epitaxial garnet film scintillators was explored. The LuGAGG:Ce and LuGAGG:Ce,Mg film scintillators with chemical formula (Ce0.01Lu0.27Gd0.74)3–wMgw(Ga2.48Al2.46)O12 were prepared and their cathodoluminescence (CL) and optical properties were studied and compared with the properties of current standard bulk single crystal YAG:Ce and YAP:Ce scintillators. More specifically, CL decay characteristics, CL emission spectra, CL intensities, optical absorption coefficients, and the refractive indices of the mentioned scintillators were measured. Furthermore, electron interaction volumes with absorbed energy distributions, photomultiplier (PMT) photocathode matchings, modulation transfer functions (MTF), and the photon transport efficiencies of scintillation detectors with the mentioned scintillators were calculated. A CL decay time for the LuGAGG:Ce,Mg film scintillator as low as 28 ns with an afterglow of only 0.02% at 1 μs after the e-beam excitation was observed. As determined from calculated MTFs, the scintillation detectors with the new film scintillators lose contrast transfer ability above 0.6 lp/pixel, while the currently commonly used YAG:Ce single crystal scintillators already do so above 0.1 lp/pixel. It was also calculated that the new studied film scintillators have an 8% higher photon transfer efficiency, even for a simple disk shape compared with the standard bulk single crystal YAG:Ce scintillator. The studied LuGAGG:Ce,Mg epitaxial garnet film scintillators were evaluated as prospective fast scintillators for electron detectors, not only in S(T)EM but also in other e-beam devices.
关键词： electron detector,multicomponent garnet film,scintillator,STEM,SEM,LuGAGG:Ce,Mg,cathodoluminescence
更新于2025-09-23 15:22:29
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Effect of doping by enantiomers with the different absolute configuration and phase sequence on mesomorphic, helical and electro-optical properties of highly tilted chiral anticlinic mixture
摘要： The main objective of the present work is to contribute to better understanding of the effect of the absolute configuration and phase sequences of dopants on the self-assembling and physicochemical properties as well as on the electro-optical parameters of a specific liquid crystalline mixture with a broad temperature range of the antiferroelectric phase. In order to establish this effect, the mesomorphic behaviour, helical pitch length and its handedness, spontaneous polarization and tilt angle, as well as electro-optical performance for all design mixture, are determined. The results show a broad temperature range of the antiferroelectric phase and very low melting points in all mixtures. Mixtures doped with (R) enantiomers exhibit longer helical pitch lengths, lower values of spontaneous polarization and rotational viscosity, comparable values of a tilt angle but also longer switch off times in comparison to similar mixtures doped with (S) enantiomers. The doping by the enantiomers exhibiting isotropic-ferroelectric-antiferroelectric phase sequence reveals the most significant impact on properties of the base mixture. The knowledge gained will very advantageous while designing new multicomponent liquid crystalline mixtures exhibiting the chiral tilted smectic mesophases for application in surface stabilized modes with passive and active matrix drive for utilization in photonics and optoelectronics.
关键词： rotational viscosity,multicomponent mixtures,antiferroelectric liquid crystals,spontaneous polarization,helical pitch,tilt angle,(S) and (R) enantiomers
更新于2025-09-23 15:21:01
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Online fire protection technology based on fiber optic gas sensor
摘要： In recent years, the production safety has been paid by a lot of attention. Although the total number of accidents in production safety has shown a downward trend, the serious accidents occur frequently and seriously. The prediction and early warning of spontaneous combustion in coal mines mainly adopts the method of gas index analysis and prediction. The traditional trace gas detection equipment used in spontaneous combustion is mainly chromatographic analysis system, which has some problems such as complicated equipment, complicated operation, slow analysis speed and inability to realize on-line monitoring. The main purpose of this study is to develop a fire risk distribution determination system based on multi-sensor information fusion technology, which is aimed at assisting fire monitoring, fire emergency management, and fire rescue. After using the information from different sensors, the system can give an effective alarm to the fire and can provide the danger degree distribution information of different areas in the building. Based on the development status of fire safety, especially the demand of fire safety for gas detection technology, the tunable laser spectroscopy technology is proposed to solve the demand problem of gas sensing products urgently needed for major fire disasters.
关键词： Optical Fiber,Fire Safety,Optical Fiber Methane Sensor,Multicomponent Gas Detection
更新于2025-09-23 15:21:01
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CuIn-ethylxanthate a a??versatile precursora?? for photosensitization of graphene-quantum dots and nanocatalyzed synthesis of imidazopyridines with ideal green chemistry metrics
摘要： Recently, the development of hybrid nano catalyst involving earth abundant transition metals for photosensitization and multi-component reaction in industry and academia has been a matter of intense study. Such hybridized catalytic systems minimize the production cost and acts as a bridged system by diversifying the application in different areas. In the present study copper indium ethylxanthate was used as a versatile precursor for synthesis of colloidal chalcopyrite phase copper indium sulphide (CC-CIS NPs) in photosensitization of graphene quantum dots and reusable powdered wurzite phased copper indium sulphide nanoparticles (PW-CIS500 NPs) for selective and efficient single pot sustainable synthesis of substituted imidazopyridines via A3 coupling strategy of an aldehyde, amine and alkyne. The material was characterized by various spectroscopic techniques viz HR-TEM, PXRD, FESEM, elemental mapping studies, UV visible spectroscopy, photoluminescence, XPS, BET and ICP-OES/MS etc. Quenching of photoluminescence intensity of colloidal CuInS2 on anchoring the graphene quantum dots (GQDs) was confirmed by photosensitization of GQDs via efficient charge transfer in CIS-GQD interface. On the other hand, the PW-CIS500 NCs catalyzed A3 coupling strategy demonstrates the high catalytic efficiency for A3 coupling reaction giving substituted imidazopyridines without losing its activity and could be recycled with a total turnover number of > 210, good E-factor of 0.13 and high RME of 88%.
关键词： multicomponent reactions,heterogenous catalysis,copper indium sulphide,copper indium ethylxanthate,imidazopyridines,graphene quantum dots,charge transfer
更新于2025-09-23 15:19:57
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Coumarin-Modified Graphene Quantum Dots as a Sensing Platform for Multicomponent Detection and Its Applications in Fruits and Living Cells
摘要： In this work, coumarin derivatives (C) are used to enhance the ?uorescence of graphene quantum dots (GQDs) by covalently linking the carboxyl groups on the edge of the GQD sheet. The as-synthesized coumarin-modi?ed graphene quantum dots (C-GQDs) have a uniform particle size with an average diameter of 3.6 nm. Simultaneously, the C-GQDs have strong ?uorescence emission, excellent photostability, and high ?uorescence quantum yield. C-GQDs and CN? can form a C-GQDs+CN? system due to deprotonation and/or intermolecular interactions. The introduced hydroquinone (HQ) is oxidized to benzoquinone (BQ), and the interaction between BQ and the C-GQDs+CN? system could lead to ?uorescence enhancement of C-GQDs. Meanwhile, the redox reaction between BQ and ascorbic acid (AA) can be used for quantitative detection of AA with CN? and HQ being used as substrates. Based on the above mechanism, C-GQDs are developed as a multicomponent detection and sensing platform, and the detection limits for CN?, HQ, and AA were 4.7, 2.2, and 2.2 nM, respectively. More importantly, satisfactory results were obtained when the platform was used to detect CN?, HQ, and AA in living cells and fresh fruits.
关键词： multicomponent detection,CN?,fluorescent probe,HQ,coumarin-modi?ed graphene quantum dots,AA
更新于2025-09-23 15:19:57
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Diversity-Oriented Synthesis and Optical Properties of Bichromophoric Pyrrole-Fluorophore Conjugates
摘要： The mild reaction conditions of the palladium-copper coupling-isomerization reaction open a highly convergent, chromogenic route to blue emissive pyrroles in the sense of a consecutive four-component reaction. By virtue of this strategy a phenol derivative can be readily accessed, which can be transformed in a level-2 transformation to a library of bichromophoric pyrrol-fluorophore conjugates by facile alkylation with fluorophore halides. The photophysics of the underlying blue emitter derivative and the conjugates is studied by absorption and emission spectroscopy, furnishing intramolecular energy transfer at short distances as well as competing fluorescence quenching. In some cases partial energy transfer results in the occurrence of dual emission, for instance seen as magenta-rose emission arising from blue and red orange luminescence. The experimental photophysical studies are rationalized by DFT and TD-DFT calculations.
关键词： DFT,multicomponent reaction,energy transfer,level-2 functionalization,absorption,emission,bichromophores,pyrrole
更新于2025-09-19 17:15:36
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Role of Aging in the Formation of Non-spherical Nanostructures during Lasera??Matter Interaction in Water
摘要： Pulsed laser ablation of different surfaces in liquid environment has broad prospects to selectively synthesize nanoparticles (NPs) with specific optical properties, as well as morphology, size and composition. The dependence of the morphology and particle size on the pulse duration and other external conditions allows synthesizing nano-sized particles for various scientific, particularly, optical, and industrial needs. Most previous studies on ablation of metals in water have shown spherical shapes of NPs without elaboration on the effect of aging on those shapes. In this study, we demonstrate notable modification in the morphology of aluminum, indium, zinc and copper NPs during aging towards the non-spherical structures, contrary to other laser ablation-induced spherical NPs from different elements in the periodic table.
关键词： cuboids,multicomponent particles,laser ablation,agglomeration
更新于2025-09-19 17:13:59