Human blood plasma-based electronic integrated circuit amplifier configuration

Dear Editor： There is accumulating evidence that human blood electronic circuit components and their application circuits become more and more important to cyborg implant/engineering, man-machine interface, hu- man disease detection and healing, and artificial brain evolutionusl. Here, we report the first development of human plasma-based amplifier circuit in the dis- crete as well as integrated circuit （IC） configuration mode. Electrolytes in the human blood contain an enormous number of charge carriers such as positive and negative molecule/atom ions, which are electri- cally conducting media and therefore can be utilized for developing electronic circuit components and their application circuits. These electronic circuits obvi- ously have very high application impact potential towards bio-medical engineering and medical science and technology.

Plasma-Based Graphene Functionalization in Glow Discharge

Glow discharge was utilized to add oxygen functional groups to the graphene platelets sample produced in chemical exfoliation synthesis. It was concluded based on Raman spectra that the graphene sample treated with the glow discharge preserves specific graphene features while no transformation to amorphous carbon is happening. SEM and EDS results indicated the increases of oxygen content in the graphene sample after the exposure to the glow discharge. Raman spectra also support the fact that the graphene platelets have been decorated with oxygen as the result of the glow discharge treatment.

Wideband radar cross-section reduction using plasma-based checkerboard metasurface

For stealth technology,in order to overcome the limitations of thin-layer plasma for electromagnetic waves attenuation and further broaden the radar cross-section(RCS)reduction(RCSR)band of the metasurface,the plasma-based checkerboard metasurface composed of plasma and checkerboard metasurface is investigated to achieve better RCSR.We designed a checkerboard metasurface which can achieve abnormal reflection to reduce RCS and whose-10d B RCSR bandwidth is from 8.1 to 14.5 GHz,the RCSR principle of it lies in the backscattering cancellation,which depends on the phase difference of artificial magnetic conductor(AMC)units.The designed plasma-based checkerboard metasurface is a thin composite structure,including a checkerboard metasurface,a plasma layer,and an air gap which is between them.Full wave simulations confirm that the plasma-based checkerboard metasurface’s–10 dB RCS reduction bandwidth and RCS reduction amplitude,are both increased under different polarized waves compared with the only single plasma or the only metasurface.We also introduced the reason and mechanism of the interaction between plasma and the checkerboard metasurface to improve the RCSR effect in detail.As plasma-based checkerboard metasurface does not need the plasma to be too thick for plasma stealth,its application in practical scenarios is easier to implement.

Growth and Physical Properties of CdS/TiO_2 Bilayer by Plasma-Based Method

The titanium oxide （TiO2） nanotubes have attracted attention for their use in dye-sensitized solar cells as photoanode. In this study semiconducting cadmium sulfide （CdS） nanoparticles arc grown on top opened TiO2 nanotubes arrays by radio-frequency magnetron sputtering. X-ray diffraction, scanning electron mieroscopy, transmission electron microscopy and diffuse reflection spectra are used to study structural, morphological and optical properties of the CdS/TiO2 bilayer.

Modeling of Inner Surface Modification of a Cylindrical Tube by Plasma-Based Low-Energy Ion Implantation

The inner surface modification process by plasma-based low-energy ion implantation（PBLEII）with an electron cyclotron resonance（ECR）microwave plasma source located at the central axis of a cylindrical tube is modeled to optimize the low-energy ion implantation parameters for industrial applications.In this paper,a magnetized plasma diffusion fluid model has been established to describe the plasma nonuniformity caused by plasma diffusion under an axial magnetic field during the pulse-off time of low pulsed negative bias.Using this plasma density distribution as the initial condition,a sheath collisional fluid model is built up to describe the sheath evolution and ion implantation during the pulse-on time.The plasma nonuniformity at the end of the pulse-off time is more apparent along the radial direction compared with that in the axial direction due to the geometry of the linear plasma source in the center and the difference between perpendicular and parallel plasma diffusion coefficients with respect to the magnetic field.The normalized nitrogen plasma densities on the inner and outer surfaces of the tube are observed to be about 0.39 and 0.24,respectively,of which the value is 1 at the central plasma source.After a 5μs pulse-on time,in the area less than 2 cm from the end of the tube,the nitrogen ion implantation energy decreases from 1.5 keV to 1.3 keV and the ion implantation angle increases from several degrees to more than 40°;both variations reduce the nitrogen ion implantation depth.However,the nitrogen ion implantation dose peaks of about 2×10^（10）-7×10^（10）ions/cm^2 in this area are 2-4 times higher than that of 1.18×10^（10）ions/cm^2 and 1.63×10^（10）ions/cm^2 on the inner and outer surfaces of the tube.The sufficient ion implantation dose ensures an acceptable modification effect near the end of the tube under the low energy and large angle conditions for nitrogen ion implantation,because the modification effect is mainly determined by the ion implantation dose,just as the mass transfer process in PBLEII is dominated by low-energy ion implantation and thermal diffusion.Therefore,a comparatively uniform surface modification by the low-energy nitrogen ion implantation is achieved along the cylindrical tube on both the inner and outer surfaces.

Antibacterial ability and biocompatibility of fluorinated titanium by plasma-based surface modification

Biomaterial surfaces with satisfied antibacterial activity and appropriate cytocompatibility are a pressing clinical need for orthopedic and dental implants.Fluorinecontaining biomaterials have been demonstrated to obtain antibacterial activity and osteogenic property,while the effect of fluorine chemical compositions on antibacterial property and cytocompatibility is rarely studied.To this end,the coatings with different fluorine chemical compositions on titanium surface were prepared by plasma treatment to verify the antibacterial ability and cytocompatibility of fluorinated surfaces.Their antibacterial ability was evaluated by using Staphylococcus aureus,and the cell compatibility was investigated with MC3T3-E1 cells in vitro.The results show that both fluorocarbon coating and metal fluorides coating exhibited a hydrophilic and nano-scaled roughness.Rather than the fluorocarbon coating,the coating composed of metal fluorides presented satisfied bactericide effect and excellent cytocompatibility.The antibacterial mechanism is associated with the metal fluorides and released fluoride ion.This work would provide novel sight in optimizing the surface modification method of fluorinated biomaterials for biomedical applications.

Determination of activation energy of ion-implanted deuterium release from W–Y2O3

The retention and release of deuterium in W–2%Y2O3 composite materials and commercially pure tungsten after they have been implanted by deuterium plasma(flux ~ 3.71 × 1021 D/m2·s, energy ~ 25 eV, and fluence up to 1.3 × 1026D/m2)are studied. The results show that the total amount of deuterium released from W–2%Y2O3 is 5.23 × 1020 D/m2(2.5 K/min),about 2.5 times higher than that from the pure tungsten. Thermal desorption spectra(TDS) at different heating rates(2.5 K/min–20 K/min) reveal that both W and W–2%Y2O3 have two main deuterium trapped sites. For the low temperature trap, the deuterium desorption activation energy is 0.85 eV(grain boundary) in W, while for high temperature trap, the desorption activation energy is 1.57 eV(vacancy) in W and 1.73 eV(vacancy) in W–2%Y2O3.

Tribological Behavior of Binary B-C Films Deposited by Sputtering-PBII Hybrid System

In this article, the authors report on the use of Radio Frequency (RF) Magnetron Sputtering combined with Plasma-Based Ion Implantation (PBII) technique to synthesize the Boron-Carbon (B-C) films. High purity of boron carbide (99.5%) disk was used as a target with an RF power of 300 W. The mixtures of Argon (Ar)-Methane (CH4) ware used as reactive gas under varying CH4 partial flow pressure at the specified range of 0 - 0.15 Pa and fixed total gas pressure and total gas flow at 0.30 Pa and 30 sccm, respectively. The effect of CH4 flow ratio on the friction coefficient of B-C films was studied. The friction coefficient of the film depended on the concentration of B. When it was 10% or lower, the coefficient decreased to 0.2 or lower. In this concentration range of B, the specific wear rate also decreased to the order of 10-7 mm3/Nm, and excellent wear resistance was displayed.

Effects of Fluorine and Silicon Incorporation on Tribological Performance of Diamond-Like Carbon Films

Diamond-like carbon (DLC) is a metastable amorphous film that exhibits unique properties. However, a number of limitations exist regarding the use of DLC, for instance, its tribological characteristics. In this article, the fluorine and silicon incorporated diamond-like carbon (F-DLC and Si-DLC) films are studied, taking into account the tribological properties of these films compared with pure DLC. The structures of the films were characterized using Auger electron spectroscopy and Raman spectroscopy. The hardness and elastic modulus were evaluated by nanoindentation hardness testing. The friction behavior was assessed using ball-on-disk friction testing and optical microscopy. The results indicated that the deposited DLC films contained 0.6 - 2.1 at.% F and 26.7 - 38.4 at.% Si. A decrease in the hardness and elastic modulus was obtained as F increased in content, which was the opposite of the behavior observed in the Si-DLC films. This was due to the shifting in the G-peak position, which is related to the sp3 bonding fraction in the film. When measured in ambient air, the addition of Si into the DLC film strongly influenced the friction coefficient, whereas doping with F only slightly influenced the films, as evidenced by their wear scars. In addition, only a 26.7 at.% Si-DLC film showed a very low friction coefficient when measured in dry air. This was attributed to the formation of silicon-rich transfer layer on the ball surfaces. Therefore, the addition of Si with 26.7 at.% content to a DLC film can be considered beneficial for improving tribological performance.

Deposition and Properties of CrN_x films by High Power Pulsed Unbalanced Magnetron Sputtering

High-power pulsed magnetron sputtering (HPPMS) technology has drawn extensively attention for producing ultra-high dense plasma and high ionization fractions of the sputtered species,depositing dense films with high performance.CrNx films were deposited on the substrates of Si(100) using high-power pulsed unbalanced magnetron sputtering (HPPUMS) technology,and the analyses of XRD and atomic force microscope (AFM) were conducted on the properties of microstructure and surface morphology of CrNx films;the friction coefficient and the adhesion between CrNx film and substrate were measured,respectively.It was found HPPUMS discharge is able to deposit CrNx films with super comprehensive properties:higher adhesive strength between the film and substrate and lower coefficient of friction.Deposition rate of CrNx films,which was tested by interferometry,was about 4.2nm/min at 0.6Pa and the pulse power density up to 6.8kW/cm2 with the pulse repetition frequency of 0.7Hz,which is about 56% of that provided by the mid-frequency magnetron sputtering discharge under the conditions of the same average power output.However,clusters with a dimension of several hundred nanometers were observed on the AFM morphology probably related to high pulse current.