Atmospheric Plasma Sterilization and Deodorization of Dielectric Surfaces

A method is presented for rapid and uniform sterilization and deodorization of dielectric surfaces. The technology is applicable to the inside surface of PET or glass bottles, polymer caps, plastic tubes, etc. The treatment is based on a pulsed RF discharge in air at atmospheric pressure (eventually with addition of argon) creating a nonequilibrium plasma on the treated surface. The plasma effectively destroys microorganisms in vegetative or sporulent form. It also slightly etches the polymeric material, removing some atomic layers and, thereby, cleaning it from aromatic organic components (deodorization). The process is short: PET bottles 1.5 L, in particular, can be treated in about 20 msec. The results of surface analysis and microbiological, chromatography, and spectroscopy tests are discussed. A device has been developed and integrated into an industrial-filling machine for online sterilization and deodorization of the inside surface of PET bottles before filling, and for sterilization of caps and bottle necks before seaming. It allows cold asceptic filling at a rate of 36,000 bottles per hour.     

Analysis of the growth of RF sputtered ZnO thin films using the optical reflective second harmonic generation

Reflective second harmonic generation (RSHG) is used to analyze the growth condition of poly crystal zinc oxide (ZnO) film with a c-axis orientation, grown on the Si substrate by RF magnetron sputtering technique. It elucidates physical phenomena exhibited by growing ZnO thin films. Connecting with analytical results of the characteristic parameters derived from the X-ray patterns and SEM images, the relationship between the RSHG intensity and the substrate temperature reveals that the effect of the grain boundaries is the domination of the RSHG mechanism. The inclined structures of ZnO films on the Si substrate are explained with reference to these RSHG patterns.     

A Reduced SNARE Model for Membrane Fusion

Let's get together : A minimal model system was developed to mimic the SNARE‐protein‐mediated fusion of biological membranes (see picture). Fusion between two populations of liposomes is controlled by a pair of complementary lipidated oligopeptides that form noncovalent coiled‐coil complexes and thereby force the membranes into close proximity to promote fusion. The model system displays the key characteristics of in vivo fusion events.

     

The influence of annealing on the properties of ZnO:Al layers obtained by RF magnetron sputtering

Al doped ZnO has been explored as a viable alternative to indium thin oxide, which is usually used as transparent electrodes' coverage but is expensive. Homogenous and durable ZnO:Al layers on glass have been obtained in radio frequency magnetron sputtering system by adjusting optimized deposition parameters, using ZnO ceramic target with 2?wt% Al₂O₃. Then, after growth process, annealing treatment has been introduced in order to improve the quality of the layers. Structural, electrical and optical properties of the obtained ZnO:Al layers are presented and discussed. From the application point of view, the best results (sheet resistance of 24 Ω/sq and transparency well above 85%) were achieved after annealing in 300?°C.     

A monolithic 180 nm CMOS dosimeter for In Vivo Dosimetry medical application

The design and development of a monolithic system-on-chip dosimeter fabricated in a standard 180 nm CMOS technology is described. The device is intended for real time In Vivo measurement of dose of radiation during radiotherapy sessions. Owing to its proposed small size, of approximately 1 mm³, such solution could be made in-body implantable and, as such, provide a much-enhanced high-resolution, real-time dose measurement for quality assurance in radiation therapy. The device transmits the related information on dose of radiation wirelessly to an external receiver operating in the MICS band. The various phases of this two years project, started in 2011, including the design and development of radiation sensors and integrated RF to perform the readout, will be described.     

Maximizing MR signal for 2D UTE slice selection in the presence of rapid transverse relaxation

Ultrashort TE (UTE) sequences allow direct visualization of tissues with very short T2 relaxation times, such as tendons, ligaments, menisci, and cortical bone. In this work, theoretical calculations, simulations, and phantom studies, as well as in vivo imaging were performed to maximize signal-to-noise ratio (SNR) for slice selective RF excitation for 2D UTE sequences. The theoretical calculations and simulations were based on the Bloch equations, which lead to analytic expressions for the optimal RF pulse duration and amplitude to maximize magnetic resonance signal in the presence of rapid transverse relaxation. In steady state, it was found that the maximum signal amplitude was not obtained at the classical Ernst angle, but at an either lower or higher flip angle, depending on whether the RF pulse duration or amplitude was varied, respectively.     

A LUT-based scheme for LNA linearization in direct RF sampling receivers

Direct RF sampling receiver – a fully digital receiver architecture – undoubtedly becomes a favored choice for HF/VHF as this approach inherently bypasses the legacy nonlinearities caused by analog components. In DRF-RF and wideband multichannel in general, LNA is still an indispensable component to ensure the receiver’s sensitivity. However, with the presence of multiple channels, the total RF power often surpasses the linear threshold that LNA and the amplified signal become severely distorted. This paper proposed a method for mitigating the LNA distortion using the look-up table (LUT) approach. Specifically, our receiver is designed with two modes of operation. In training mode, a built-in signal circuit generates a training signal for extracting the LNA characteristic and eventually reconstructs the inverse LNA nonlinear model in the form of a LUT memory. During the receiving mode, a linearization circuit reverses the distortion impact by matching the RF power level with the inverse nonlinear model pre-stored in the LUT. The effectiveness of the proposed distortion compensation method first is evaluated by a MATLAB simulation with a multi-channel DRF-RF model. The simulation results show that the proposed approach significantly improved the SNDR for the channel of interest. Furthermore, the model has been practically verified, where the actual distorted signals are sampled from a commercial LNA (ZFL-500LN+) by a customized FPGA board. Results from measurements show an improvement of $\sim$7 dB for SNDR and 27% for EVM in a strong distortion scenario of QPSK modulation signal.     

射频等离子硫钝化GaAs(100)的表面特性

采用射频等离子方法,对Ga As(100)衬底片表面进行干法硫等离子体钝化,旨在得到性能稳定含硫钝化层。样品经过360℃温度条件下的快速热退火,光致发光(PL)测试表明,钝化后的样品PL强度上升了71%。同时,钝化样品的稳定性测试结果表明,样品放置在实验室空气中30 d,其PL强度未出现明显变化,说明Ga As的等离子体干法硫钝化具有较好的性能稳定性。     

BEPCII新加速管的高功率测试和老练

BEPCⅡ(北京正负电子对撞机重大改进工程)要求其直线注入器提供更高的能量和流强,为此必须改进正电子产生靶前后的加速管,以提高加速梯度,并消除原有加速管因长期运行后性能有所下降的隐患.本文叙述了新加速管的高功率测试,包括测试装置的设计、建立,微波功率源(速调管)的调试和加速管高功率测试结果及其分析.