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Optical Transfection
摘要： Strategies for the delivery of genes into eukaryotic cells fall into three categories: transfection by biochemical methods, transfection by physical methods, and virus-mediated transduction. “Optical transfection”—a physical transfection method—exploits the ability of light to create small transient pores in the plasma membrane of mammalian cells.
关键词： plasma membrane,laser,eukaryotic cells,Optical transfection,gene delivery
更新于2025-09-09 09:28:46
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ions
摘要： Laser-produced Sn plasma sources are used to generate extreme ultraviolet light in state-of-the-art nanolithography. An ultraviolet and optical spectrum is measured from a droplet-based laser-produced Sn plasma, with a spectrograph covering the range 200–800 nm. This spectrum contains hundreds of spectral lines from lowly charged tin ions Sn1+?Sn4+ of which a major fraction was hitherto unidenti?ed. We present and identify a selected class of lines belonging to the quasi-one-electron, Ag-like ([Kr]4d 10 nl electronic con?guration), Sn3+ ion, linking the optical lines to a speci?c charge state by means of a masking technique. These line identi?cations are made with iterative guidance from COWAN code calculations. Of the 53 lines attributed to Sn3+, some 20 were identi?ed from previously known energy levels, and 33 lines are used to determine previously unknown level energies of 13 electronic con?gurations, i.e., 7p, (7, 8)d, (5, 6)f , (6–8)g, (6–8)h, (7, 8)i. The consistency of the level energy determination is veri?ed by the quantum-defect scaling procedure. The ionization limit of Sn3+ is con?rmed and re?ned to 328 908.4 cm?1, with an uncertainty of 2.1 cm?1. The relativistic Fock-space coupled-cluster (FSCC) calculations of the measured level energies are generally in good agreement with experiment but fail to reproduce the anomalous behavior of the 5d 2D and nf 2F terms. By combining the strengths of the FSCC calculations, COWAN code calculations, and con?guration interaction many-body perturbation theory, this behavior is shown to arise from interactions with doubly excited con?gurations.
关键词： Sn3+ ions,energy-level structure,nanolithography,laser-produced plasma,extreme ultraviolet light
更新于2025-09-09 09:28:46
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Deoxynivalenol Decontamination in Raw and Germinating Barley Treated by Plasma-Activated Water and Intense Pulsed Light
摘要： The contamination of barley kernel by Fusarium fungi constitutes a serious problem for malting-related industries. Deoxynivalenol (DON) is a secondary metabolite produced by Fusarium fungi. DON can affect dopaminergic receptors in the human brain; it may cause symptoms such as vomiting, diarrhea, headache, and fever. The aims of this study were to evaluate the DON destruction effect of the intense pulsed light (IPL) and plasma-activated water (PAW) treatments in raw and germinating barley and assess the feasibility for disinfection in the malt industry. Both non-thermal methods degraded DON concentration in germinating barley. IPL treatment significantly reduced (p < 0.05) the DON level of germinating barley samples by 35.5% after 180 pulses in 60 s, and the PAW treatment effectively degraded the DON level by 34.6% in germinating barley in the first 5 min. However, higher barley quality remained for PAW treatment (germination rate: 81–100%) than for the IPL treatment (germination rate: 41–60%). For the raw barley samples, although significant reduction (30.9%) was achieved after 180 pulses of IPL treatment, noticeable quality (germination rate: 20–40%) alteration was observed. Significantly less DON degradation was achieved by the PAW treatment on raw barley than the germinating barley for all times. Overall, these findings suggested that PAW and IPL might potentially be used to reduce DON levels in some malt-related industry applications, and PAW was recommended as a better method than IPL to maintain the barley quality.
关键词： Deoxynivalenol degradation,Non-thermal treatment,Barley kernel,Plasma-activated water,Intense pulsed light
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE Avionics and Vehicle Fiber-Optics and Photonics Conference (AVFOP) - Portland, OR, USA (2018.11.13-2018.11.14)] 2018 IEEE Avionics and Vehicle Fiber-Optics and Photonics Conference (AVFOP) - Linear Ring Modulators with DC Kerr Phase Shifters
摘要： We demonstrate a silicon ring modulator with linear phase shift versus voltage, derived from the interplay between plasma dispersion effect and DC Kerr effect. The dynamic range is 103.6 dB. Hz2/3 at a 1.2 GHz carrier.
关键词： silicon ring modulator,plasma dispersion effect,linear phase shift,dynamic range,DC Kerr effect
更新于2025-09-09 09:28:46
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GeSn surface preparation by wet cleaning and in-situ plasma treatments prior to metallization
摘要： GeSn, a group IV binary alloy, is currently of high interest. Its use is envisioned in two kinds of applications: (i) as a source/drain compressive stressor in order to boost the hole mobility in short gate length Ge channel p-type MOSFETs [1] and (ii) as a direct-band-gap material for Si photonics, provided that the Sn content is higher than 10%, typically [2]. However, the fabrication of GeSn-based components faces major technological issues. First of all, as the lattice mismatch between Sn and Ge is large (14%) and the solubility of Sn in Ge low at thermodynamic equilibrium (< 1%), specific conditions have to be used for the epitaxial growth of high Sn content GeSn layers. Moreover, the fabrication of efficient ohmic contacts to receive and deliver power and signals is challenging. Ni-stanogermanides are currently under investigation in order to benefit from low contact resistivity (Rc) and sheet resistance (Rsh) in GeSn-based devices. The surface preparation of such metastable alloys will then be an unavoidable step. Whatever the targeted application, wet cleaning is indeed mandatory to remove particles, organic materials, metallic impurities and native oxides from the surface. Literature data on GeSn surface preparation prior to metallization is currently scarce [3], [4]. Based on the existing knowledge on pure germanium, we will likely have to cope with a high dissolution in oxidant solutions (GeO2 dissolution in water) and unstable surface preparations (high reactivity upon air and oxygen exposure). Ex-situ wet cleanings will likely suffer from a fast native oxide regrowth on the GeSn surface. In-situ plasma treatments in a chamber connected to the metal deposition chamber itself, i.e. without any air break, should enable to get rid of that problem. In this work, after a characterization of the native oxide formed upon air exposure of Ge0.85Sn0.15 alloys, we investigate the impact of i) wet chemistries, ii) plasma treatments and iii) “wet + plasma” combinations on GeSn surface oxide removal.
关键词： surface preparation,GeSn,metallization,wet cleaning,plasma treatments
更新于2025-09-09 09:28:46
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Structure and Stability of C:H:O Plasma Polymer Films Co-Polymerized Using Dimethyl Carbonate
摘要： C:H:O plasma polymer ?lms (PPFs) were deposited by means of plasma-enhanced chemical vapour deposition using the non-toxic, biodegradable organic compound dimethyl carbonate (DMC) at various plasma powers and pressures in order to control the degradation properties related to the carbonate ester group. Coating properties using pure DMC monomer vapours were compared to co-polymerized ?lms from gaseous mixtures of DMC with either ethylene (C2H4) or carbon dioxide (CO2) affecting deposition rate and chemical composition. C:H:O ?lm properties were found to depend primarily on the amount of oxygen in the plasma. To investigate the PPF stability during aging, changes in the composition and properties were studied during their storage both in air and in distilled water over extended periods up to 5 months. It was shown that aging of the ?lms is mostly due to oxidation of the plasma polymer matrix yielding slow degradation and decomposition. The aging processes and their rate are dependent on the intrinsic amount of oxygen in the as-prepared C:H:O ?lms which in turn depends on the experimental conditions and the working gas mixture. Adjustable ?lm properties were mainly attained using a pure DMC plasma considering both gas phase and surface processes. It is thus possible to prepare C:H:O PPFs with controllable degradability both in air and in water.
关键词： plasma polymerization,aging,degradability,thin ?lms,chemical composition
更新于2025-09-09 09:28:46
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Antena impresa invertida reconfigurable en frecuencia a base de una microdescarga de plasma
摘要： This paper proposes the study of an inverted microstrip plasma-based reconfigurable antenna. The scope is to generate controlled microplasma inside the cavity between the antenna ground plane and its main conductor. This plasma will modify the resonant frequency of the antenna. The interest of using a plasma discharge as an active reconfigurable element is its switching time and mainly its capability of handling high microwave power. It was demonstrated, theoretically, that the reconfiguration frequency of a microstrip patch antenna with a microdischarge in its cavity, depends on the electron density of the plasma. Furthermore, a prototype of an X-Band inverted microstrip patch antenna, which integrates a microdischarge, was implemented. The measured frequency excursion for this prototype was 180 MHz.
关键词： Reconfigurable antenna,frequency tuning,plasma discharge
更新于2025-09-09 09:28:46
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On evaluating x-ray imaging crystals with synchrotron radiation
摘要： Bent crystals used in diagnostics of plasmas combine x-rays diffracted from across the crystal. Therefore imperfections in the resulting 1-D spectrum or 2-D image are not the best way to find out why one particular crystal may differ in its performance from another and what, if anything, to do about it. Instead, here we want to measure the diffraction locally, with the necessary resolution. Nominally monochromatic and unidirectional radiation from the synchrotron’s standard x-ray optics proved to be insufficient for the purpose. Here much better radiation comes from the x-ray topography setup at the x-ray optics testing beamline 1-BM at the Advanced Photon Source, thanks to a specially designed quartz conditioning crystal. Some worrisome features in a bent crystal’s diffraction have thereby disappeared, while minor fabrication flaws remain highly visible.
关键词： x-ray imaging,diffraction,synchrotron radiation,plasma diagnostics,bent crystals
更新于2025-09-09 09:28:46
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Temporal variation of the spatial density distribution above a nanosecond pulsed dielectric barrier discharge plasma actuator in quiescent air
摘要： The thermal perturbation caused by a nanosecond pulsed dielectric barrier discharge (ns-DBD) plasma actuator may lead to boundary layer transition. Hence, understanding of the thermal flow induced by the ns-DBD plasma actuator will contribute to the development of an efficient flow control device for various engineering applications. In this study, the spatial density distribution related to the thermal flow was experimentally investigated using both qualitative and quantitative schlieren techniques. The focus of this study is to understand the initial temporal variation of the spatial density distribution above the ns-DBD plasma actuator in quiescent air. The quantitative visualisation showed that a hot plume is generated from the edge of the exposed electrode and moves slightly towards the ground electrode. A possible explanation is that an ionic wind and/or an induced jet leads to the movement of the hot plume. However, the plasma-induced flow (the ionic wind and the induced jet) is generated after the primary plasma discharges; namely, the hot plume does not move immediately after the first plasma discharge. At almost the same time as the movement of the hot plume, consecutive plasma discharges enhance the density of the hot plume; thereafter, the density reaches almost a steady state.
关键词： nanosecond pulsed dielectric barrier discharge,plasma actuator,schlieren techniques,boundary layer transition,thermal perturbation
更新于2025-09-09 09:28:46
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Spark Plasma Sintering of Silicon Carbide with Al <sub/>2</sub> O <sub/>3</sub> and CaO: Densification Behavior, Phase Evolution and Mechanical Properties
摘要： Liquid phase sintering (LPS) often yield an amorphous grain boundary region which deteriorates the high temperature properties of the sintered ceramics and thus ceramists prefer to obtain a crystalline grain boundary after LPS. This paper deals with LPS of silicon carbide ceramics to near theoretical density, understanding the densification behavior, evolution of gehlenite phase and subsequent evaluation of their mechanical properties. High density SiC ceramics were fabricated from sub-micrometre α-SiC powders with the aid of refractory phase forming metal oxide additives by spark plasma sintering. Sintering temperature and holding time at peak temperature were varied to study their effect on densification and mechanical properties. Density of the sintered ceramics reached ~97% at 1800oC. Microstructural features and crack propagation mode were studied using scanning electron microscopy. XRD analysis confirmed the presence of crystalline gehlenite phase in the sintered samples. Hardness, fracture toughness and flexural strength of the sintered ceramics were determined by standard test procedures.
关键词： Liquid phase sintering,Fracture toughness,Spark plasma sintering,Silicon carbide,Mechanical properties
更新于2025-09-09 09:28:46