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Amoxicillin (AMX) is one of the most widely used antibiotic drugs, which plays an effective role in eliminating bacterial and fungal diseases. However, on account of its poor biodegradability, AMX often leads to water pollution. In this study, the AMX in water was oxidized by atmospheric-pressure air microplasma (APAM). The degradation pathway of AMX in aqueous solution was studied at the molecular level by high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS). The results show that AMX can be rapidly removed by APAM. Meanwhile, eight intermediate and two final degradation products were detected. The reactivity of the AMX with different active species generated by APAM can be described in the following sequence: hydroxyl radical ( $\cdot $ OH) > hydrogen peroxide (H2O2) > ozone(O3). The APAM treatment is a promising way to oxidize AMX in the aqueous solution into CO, CO2, and H2O.

Over the last two decades, atmospheric-pressure plasma has been investigated intensively as an advanced oxidation process for water. This current study is to focus on the generation mechanisms of H2O2 in the liquid treated by atmospheric-pressure He plasma. The effect of H2O2(aq) on the removal percentage of isopropanol (IPA) in liquid is evaluated after He plasma jet treatment. The effects of IPA as ·OH(g) and ·OH(aq) scavenger on the generation of H2O2(aq) are studied by changing the initial IPA solution temperature. Our analysis indicates that H2O2(aq) is mainly formed by the H2O2(g) dissolution into liquid. The combination of ·OH(aq) is not important for the formation of H2O2(aq) in liquid. When the exogenous H2O2 is added into IPA solution, the IPA removal percentage can be improved by the He plasma jet treatment due to the fact that exogenous H2O2 is decomposed to ·OH by e−, H radicals, and He and He2 metastables. This study is important for understanding the reaction pathways of H2O2(aq) in plasma treated liquid.

At present, the standard left atrial appendage occlusion procedure mainly involves two-dimensional imaging methods such as X-ray fluoroscopy and transesophageal echocardiography to guide the operation, which will lead to underestimation of the three dimensional structure of the left atrial appendage and the surrounding tissue, thus adversely affects the surgery. To solve this problem, a surgery assist system for left atrial appendage occlusion based on preoperative cardiac CT images is developed. The proposed system realizes the left atrial appendage parameter measurement based on cardiac CT image, and realizes the calculation of optimal delivery sheath trajectory and three-dimensional simulation of the delivery sheath movement on the basis of a novel delivery sheath trajectory model. The system is expected to provide precise guidance for left atrial appendage occlusion, improve the success rate and safety of the operation, and at the same time help reduce the difficulty of learning the operation, and facilitate the promotion of left atrial appendage occlusion.

Plasma depollution is a relatively new field that investigates potential applications of atmospheric pressure plasma in environmental engineering, such as microorganism inactivation and degradation of organic molecules in water. In order to enunciate mechanisms of degradation of organic matter at molecular or atomic levels, the interaction between He, N2, O2, and air plasma jet and methanol in water was analyzed by gas chromatography–mass spectrum and Fourier transform infrared spectroscopy. Results show that the efficiency of methanol degradation is strongly dependent on the working gas and plasma treatment time. Compared to atmospheric pressure N2, O2, and air plasma jet, the He plasma jet may be utilized to degrade methanol more efficiently in aqueous solution. The efficiencies of degradation of methanol in water can be well described by using the chemical reaction rate model, where reactive oxygen and hydroxyl radical species play crucial roles in the degradation process. This paper provides an insight into the mechanism of degradation of organic pollutant in water by plasma.

C2H2-SCR of NOx over one-stage dielectric barrier discharge (DBD) plasma system combined with Ag modified alumina catalyst at excess oxygen was carried out. NOx and C2H2 conversions and COx selectivity dependence on reaction temperature and discharge voltage were investigated systematically. At low temperatures, a synergistic effect of HC-SCR of NOx in one-stage DBD plasma and 2 wt% Ag/Al2O3 catalyst was clearly observed. The improvement on the NO+O2 co-adsorption and formation of more active nitrate species adsorbed on 2 wt% Ag/Al2O3 catalyst by plasma was analyzed by MS-TPD and TPSR methods.

Atmospheric DBD Ar and air plasmas were directly generated by the multi-needle to plate electrodes configuration in the water and diagnosed by the electrical measurements and the optical emission spectroscopy. The proportion of displacement current in the total current was much small, which indicated that the input power was almost used to produce the Ar and air plasmas. The corresponding effective power was in the range of 27.79 (34.59)-56.58 (79.87) W for Ar (air) discharge. The gas temperature increased from 607 (629) to 703 (758) K and the electron temperature was in the range of 1.36 (1.39)-1.64 (1.87) eV, and the electron density reached to 1014 cm−3 orders of magnitude for Ar (air) discharge, when peak applied voltage increased from 7 (9) to 10 (12.5) kV.

In this study, we have modeled the sputtering process of energetic He+ ions colliding with W nano-fuzz materials, based on the physical processes, such as the collision and diffusion of energetic particles, sputtering and redeposition. Our modeling shows that the fuzzy nanomaterials with a large surface-to-volume ratio exhibit very high resistance to sputtering under fusion-relevant He+ irradiations, and their sputtering yields are mainly determined by the thickness of fuzzy nano-materials, the reflection coefficients and mean free paths of energetic particles, surface sputtering yields of a flat base material, and the geometry of nano-fuzz. Our measurements have confirmed that the surface sputtering yield of a W nano-fuzz layer with the columnar geometry of nano-fuzz in cross-section is about one magnitude of order lower than the one of smooth W substrates. This work provides a complete model for energetic particles colliding with the nano-fuzz layer and clarifies the fundamental sputtering process occurring in the nano-fuzz layer.

A tube–to-plate dielectric barrier discharge He plasma was directly generated in water by 8 kHz sinusoidal excitation voltage. It was found that the average power, rotational temperature of OH, electronic excitation temperature, electron temperature, and electron density increased linearly with the increase of applied voltage and with the value in the range of 3.65–11.13 W, 427–529 K, 4355–4533 K, 1.15–1.96 eV, and 2.56 × 10 14 –5.76 × 10 14 cm −3 , respectively. Furthermore, the optical emission spectrum indicated that active He*, O*, N 2 *, N 2 + *, and OH* species existed in He plasma.

A dielectric barrier discharge argon plasma was generated with tube–to-plate electrodes in the water by a sinusoidal excitation voltage at atmospheric pressure. Time-averaged optical emission spectroscopy was used to measure the plasma parameters, of which the rotational temperature of OH was obtained by comparing the simulated spectrum with the measured spectrum at the A 2 Σ + → X 2 Π band transition and the electronic excitation temperature was determined by Boltzmann’s plot method. Furthermore, the emission intensity ratio of atomic argon lines λ = 811.5 nm to λ = 750.4 nm was used to determine the electron temperature and the Stark broadening of the hydrogen Balmer Hα line was applied to measure the electron density. It has been found that the electron temperature and density in this argon plasma were in the range of 1.02–1.43 eV and on the order of 1014 cm−3, respectively, and the excitation temperature, rotational temperature, and electron density increase with the increase of applied voltage. Besides, the properties of the argon dielectric barrier discharge were also studied by electrical diagnosis.

In this study, the effect of atmospheric-pressure air surface dielectric barrier discharge (SDBD) on the degradation of Omethoate smeared edible wolfberry was investigated by gas chromatography and mass spectrometry (GC–MS). The degradation efficiency of SDBD on Omethoate is shown to be strongly dependent on the discharge voltage and plasma treatment time. The plasma-induced degradation mechanisms were studied through identification of the intermediates or by-products generated during SDBD plasma treatment. The results show that the degradation efficiency may be higher than 99% under the optimum discharge conditions, i.e., at the applied voltage of 10 kV and the treatment time of 30 min. It is concluded that the atmospheric-pressure SDBD plasma may degrade pesticide residue into nontoxic species (such as PO43−, H2O, SO42−, and CO2) during the plasma treating process.

We applied a low-intensity pulsed transcranial ultrasound stimulation (pTUS) to the ischemic cortex after a distal middle cerebral artery occlusion (dMCAO) to study whether pTUS is capable of protecting brain from ischemic injury.Rats were randomly assigned to Sham (n = 6), Control (n = 16), and pTUS (n = 16) groups. The pTUS-treated rats were subjected to 60-min ultrasonic stimulation immediately after the ischemia. After 48 h, the sensorimotor-related behavioral outcomes were assessed by a neurological severity score (NSS), and the permanent brain injury was assessed by the histologic analysis of TTC staining of brain slices.pTUS group showed significantly lower NSS (n = 10, 5.5 ± 2.5) than the Control group ( n = 10, 10.5 ±1.4) (p0.01). Concordantly, the ischemic lesion was significantly reduced after receiving pTUS immediately after dMCAO. The cortical infarct volume in the control group was more than threefold of the pTUS group (43.39% ± 2.33%, n = 16 versus 13.78% ± 8.18%, n = 16, p0.01). Immunohistochemical staining indicated reduction of neutrophils in the affected area, and laser speckle imaging showed significant increase of a cerebral blood flow after pTUS, which consistently supported the neuroprotection of pTUS in ischemic brain injury.Both behavior and histological results suggested that pTUS on ischemic core immediately after ischemic stroke could be neuroprotective.The noninvasiveness and high spatiotemporal resolution of pTUS makes it a unique neuromodulation technique in comparison with the current TMS and tDCS.

In this paper, we report on the propagation behavior of the atmospheric-pressure and brush-shaped He/O 2 plasma plumes generated by a specially designed plasma device. The measurements show that the frequency of applied voltage (f) and the O 2 fraction and flow rate of the feed gas significantly affect the discharge propagation of the atmospheric-pressure plasma plume in ambient air. The uniformity of the brush-shaped plasma plume is greatly improved at a relatively high f or He/O 2 flow rate. Addition of a trace amount of O 2 into the He gas can also contribute to the formation of uniform and brush-shaped plasma plumes in ambient air. This paper confirms that the plasma device composed of well-aligned and micrometer-thick fibers can be utilized to generate large-scale plasma plumes for potential applications. The propagation of the He/O 2 plasma plume in ambient air results from the applied electric field across the small gas spacing of a barrier discharge electrode configuration, where the He atoms are easily ionized or excited for generating the brush-shaped plasma.

Plant diseases resulting from plant pathogens are profoundly affecting crops worldwide. In this study, the tomato pathogen Cladosporium fulvum (C. fulvum) have been inactivated by using the atmospheric-pressure plasma jet (APPJ). The results show that the inactivation efficiencies of C. fulvum are dependent on the plasma density and treatment time. The APPJ with a relatively high plasma density can completely kill the resistant C. fulvum within the treatment time of 60 s. Due to plasma generating electrostatic force, the outer membrane of C. fulvum is disrupted and the cytoplasm is released to the surrounding medium. Both protein and DNA molecules can be destroyed during the plasma inactivation. Meanwhile, the APPJ can also provide a novel approach to decrease the rotting rates of C. fulvum-infected tomato seeds.

National Natural Science Foundation of China [10875025, 20803007]; Fundamental Research Funds for Central Universities of China [DC12010116, DC13010106]; Program for Liaoning Excellent Talents in University [LJQ20l3128]

High-energy (260 keV) He + pre-damaged and undamaged polycrystalline tungsten samples were irradiated with low-energy (220 eV) and high-flux (∼10 21 ions/m 2 s) He + at a sample temperature of 873 K to a fluence of 1.0 × 10 25 ions/m 2 . Microscopic evolution of these samples was carried out using non-destructive conductive atomic force microscopy and a nanohardness test. Analysis indicates that a large number of nanometer-sized protuberances of irradiated tungsten samples results from over-high internal pressure of nanometer-sized helium bubbles. Ordered and nanostructured helium bubbles with the same diameter and average spacing can be formed due to the self-trapping and self-organizing of helium atoms in the tungsten materials. In the case of pre-damaged, low-energy He + irradiation results in a random distribution of nanostructured helium bubbles, indicating that high-energy He + implantation results in serious irradiation damage of tungsten materials, acting as nuclei for helium bubbles.

In this study, we designed one portable plasma device to generate a stable and brush-shape air discharge at atmospheric pressure for the plasma inactivation of Escherichia coli cells. The design of the portable plasma device based on the alignment of tens of air microplasmas resulted in the room-temperature and brush-shape plasma (50 mm in length and 5 mm in width). The brush-shape plasma was very efficient for the large-area inactivation of E. coli cells, and E. coli cells in direct contact with the air plasma were completely killed within the treatment time of 1 min. XPS analysis showed that the surface of plasma-activated E. coli cells was predominantly composed of C–O or C=O groups, indicating the oxygen-containing species in the air plasma were able to break the C–C or C–H bonds and cause the etching of organic compounds. Analysis indicated that lethal effects on E. coli cells were largely ascribed to the chemical erosion, i.e. damage to the cell wall or cell membrane. Analysis also indicated that both short-living species, such as O and OH radicals, and ozone molecules could play a crucial role in the plasma inactivation process by this method.

National Magnetic Confinement Fusion Program [2011GB108011, 2011GB108007]; National Science Foundation of China [NSF-20803007, NSF-11175038, NSF-10875025]; Fundamental Research Funds for the Central Universities [DC12010116]

National Magnetic Confinement Fusion Program [2011GB108011]; National Science Foundation of China [NSF-20803007, NSF-11175038, NSF-10875025]; Fundamental Research Funds for the Central Universities [DC12010116]; Funds for Young Excellent expert by Dalian Government [2009J22DW017]

Ultrathick (> 25 μm) carbon films were obtained on the inner surface of hollow and micron-thick quartz fibers by confining CH 4 /He or C 2 H 2 /He microplasmas in their hollow cores. The resulting carbon films were studied by using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The microplasma-enhanced chemical vapor deposition (CVD) technique resulted in the uniform growth of amorphous carbon films on the inner surface of very long (> 1 m) hollow-core fibers. Film deposition is performed by using microplasmas at atmospheric pressure and at 50 Pa. The carbon films obtained with the latter show the smooth inner surfaces and the well continuity across the film/optical fiber. Low-pressure CH 4 /He and C 2 H 2 /He microplasmas can lead to a rapid growth (~ 2.00 μm/min) of carbon films with their thickness of > 25 μm. The optical emission measurements show that various hydrocarbon species were formed in these depositing microplasmas due to the collisions between CH 4 /C 2 H 2 molecules and energetic species. The microplasma-enhanced CVD technique running without the complicated fabrication processes shows its potentials for rapidly depositing the overlong carbon tubes with their inner diameters of tens of microns.

National Magnetic Confinement Fusion Program [2011GB108011]; National Science Foundation of China [NSF-20803007, NSF-11175038, NSF-10875025]; Fundamental Research Funds for the Central Universities [DC12010116]; Dalian Government [2009J22DW017]

Inductively coupled plasma was used to study the removal of NO x from NO/N 2 /O 2 /C 2 H 4 mixtures in Co-ZSM-5 packed radio frequency (RF) plasma. Laser-induced fluorescence (LIF), optical emission spectroscopy (OES), and mass spectroscopy temperature programmed desorption (MS-TPD) were applied to investigate the effects of the plasmas parameters, such as discharge power ( P dis ), discharge pressure ( p ) on the concentration of reactive species in the gas phase or stable surface species formed over catalyst active sites. Rotational and vibrational temperatures of N 2 in Co-ZSM-5 packed and no packed RF plasmas were also analyzed. Possible mechanism for the NO x -selective catalytic reduction (SCR) with C 2 H 4 over Co-ZSM-5 packed RF plasmas was addressed.

Tussah pebrine disease resulting from Nosema bombycis (NB) spores causes massive production and economic losses in the silk industry in China. This paper reports on highly effective inactivation of NB spores for the control of pebrine disease by using an atmospheric pressure cold plasma jet. Both Giemsa dyeing measurement and tussah breeding experiment show that the atmospheric pressure He plasma jet containing 1% ${\rm O}_{2}$ kills almost all the NB spores with a $10^{7}$ population within an exposure time of 5 min. Scanning electron microscopy measurements and UV absorbance spectra show that plasma inactivation has withered up the NB spores and resulted in the spores inactivated. Both energy dispersive spectroscopy and optical emission spectroscopy measurements showed that plasma-created reactive particles, such as O and accompanied charged species can play an important role in the inactivation processing.

A surface discharge device composed of microns-thick hollow quartz fibers is used to inactivate resistant fungi cells. The homogeneous cold plasmas are generated by using a pulse high-voltage source with the repetition frequency of 150 Hz at atmospheric-pressure. Increasing pulse voltage slightly from 26 to 34 kV leads to an obvious improvement in the inactivation efficiency of fungi cells. The atmospheric-pressure air plasma generated at the pulse voltage of 34 kV is found to kill the fungi cells as much as 99% within a treatment time of 5 min. The inactivation efficiency is systematically investigated as a function of the processing depth of surface plasma. Various measurements indicate that plasma activated derivatives, such as OH, O, O3, and charged species play a key role in this plasma inactivation process.

National Magnetic Confinement Fusion Program [2011GB108011]; National Science Foundation of China [NSF-20803007, NSF-11175038, NSF-10875025]; Fundamental Research Funds for the Central Universities [DC12010116]; Dalian Government [2009J22DW017]

A barrier discharge experimental setup for low-pressure and large-area (400 mm × 600 mm) surface modification of polymers is reported. The low-pressure barrier discharge plasma consists of pulsed and glow-like breakdowns with peak widths of several microseconds and leads to the uniform surface modification of polymers. In contrast, the filamentary discharges produced at atmospheric pressure cause surface damage and nonuniform treatment of polymers. This study indicates that barrier discharge plasmas generated in the small gas spacing at low discharge pressure result in efficient collisions between polymer surface and activated species, and an extremely low consumption of feed gas and discharge power.

Hydrogenated amorphous carbon nitride (a-C:N:H) films were synthesized from CH 4 /N 2 , C 2 H 4 /N 2 and C 2 H 2 /N 2 mixtures using dielectric barrier discharge (DBD) plasmas. Atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) were used to characterize the surface morphology, bonding structure, and composition of the a-C:N:H films. The influences of plasma parameters (discharge pressure in the range of 25–1000 Pa) and feed gases used on the composition and the structure of deposited films were systematically studied. The a-C:N:H films with the uniform surface structure were deposited by low-pressure DBD plasmas with various systems. Compared to the films deposited in C 2 H 4 /N 2 and C 2 H 2 /N 2 systems, the films deposited in the CH 4 /N 2 system exhibit the relatively lower surface roughness and deposition rate. For all the films prepared in these three systems, increasing the discharge pressure leads to an increase in film surface roughness and deposition rate. Significant differences among the FTIR spectra of all deposited a-C:N:H films were also observed. Both FTIR and XPS spectra show that for all the films deposited in three different systems, increasing the N 2 fraction leads to a decrease in the H content of deposited a-C:N:H films and an increase in the N content. The properties of deposited films may change from those of polymerlike to diamond-like when the discharge pressure is increased. Correlations between the film properties and growth processes are discussed in this study.

Fluorocarbon (FC) films have been deposited using pulsed and continuous wave (cw) radio frequency (rf) plasmas fed with hexafluoroethane (C2F6), octafluoropropane (C3F8), or octafluorocyclobutane (C4F8). The effects of feed gases used, discharge pressure, rf power, substrate positions and discharge modes (pulsed or cw) on the deposited films are examined. Film properties are determined using X-ray photoelectron spectroscopy, atomic force microscopy, and static contact angle measurements. The contact angles of FC films are well related to their compositions and structures. Feed gases used, discharge pressure, rf power, substrate positions and discharge modes strongly affect the morphology of the resulting film, as revealed by atomic force microscopy. Optical emission spectrometry measurements were performed to in-situ characterize the gas-phase compositions of the plasmas and radicals’ emission intensities during film deposition. Correlations between film properties, gas-phase plasma diagnostic data, and film growth processes were discussed. The film growth in pulsed or downstream plasmas was controlled by the surface migration of radicals, such as CF2 towards nucleation centers, which result in the deposition of FC films with less cross-linked nature and rougher surfaces. These results demonstrate that it is possible to control film compositions and surface structure by changing deposition parameters.

Gas discharge in a small radius dielectric tube may result in atmospheric pressure plasma jets with high energy and density of electrons. In this study, the atmospheric pressure ionization waves (IWs) were generated inside a tapered tube. The propagation behaviors of IWs inside the tube were studied by using a spatially and temporally resolved optical detection system. Our measurements show that both the intensity and velocity of the IWs decrease dramatically when they propagate to the tapered region. After the taper, the velocity, intensity, and electron density of the IWs are improved with the tube inner diameter decreasing from 4.0 to 0.5 mm. Our analysis indicates that the local gas conductivity and surface charges may play a role in the propagation of the IWs under such a geometrical constraint, and the difference in the dynamics of the IWs after the taper can be related to the restriction in the size of IWs.

Dielectric barrier discharges have been used to deposit fluorocarbon (FC) films on various materials, such as paper, glass, and silicon substrates. The primary monomers used for plasma polymerization were difluoromethane (CH2F2), octafluoropropane (C3F8), and octafluorocyclobutane (C4F8). FC films were characterized using Fourier transform infrared spectroscopy, atomic force microscopy, static contact angle measurements, and scanning electron microscopy. Surface and structural properties of deposited films are strongly dependent on the plasma compositions and plasma parameters. FC films deposited on paper are to enhance its barrier properties and to achieve hydrophobic surfaces. Contact angle studies reveal that a minimum FC film thickness of about 200 nm on paper is required to completely cover surface and near-surface fibers, thereby providing the paper with long term hydrophobic character. In the C3F8 and C4F8 systems, the contact angles of the deposited films do not change appreciably with plasma parameters and are strongly dependent on the substrate roughness. Hydrogenated FC films deposited with CH2F2 plasmas show the relatively low contact angles due to the existence of CHX (x = 1–3) groups.

Fluorocarbon (FC) films deposited in continuous wave (cw) and pulsed difluoromethane radio frequency (r.f.) plasmas were characterized using Fourier transform infrared spectroscopy and atomic force microscopy. The effects of varying r.f. power, cw/pulsed discharge mode, and the distance of the substrate from the coil on the deposition rate, film structure, and surface roughness were investigated. These cw and pulsed deposition systems were characterized in-situ by means of optical emission spectroscopy. Emission intensities of H α , H β , H 2 and carbon-containing species in the coil region and downstream plasmas as a function of plasma parameters were measured. The hydrogen excitation temperature obtained from the relative emission intensities of H α and H β lines shows a clear dependence on the r.f. power and the substrate position. Correlations between film properties, gas-phase plasma diagnostic data, and film growth processes were discussed. Experimental results indicate that the film growth within the coil region in cw plasmas is controlled by the synergistic effect between energetic ions and low-energy species. The film growth in pulsed and downstream plasmas is controlled by the growth of coalesced nuclei via surface diffusion of adsorbed species, which results in the deposition of FC films with relatively rough surfaces.

Low-pressure dielectric barrier discharge (DBD) plasmas have been used to deposit polymerized fluorocarbon (FC) films on silicon substrates. The effects of discharge pressure and frequency of power supply on the film quality have been systematically investigated. The deposited films were characterized by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and static contact angle measurements. Experimental results show that FC films with a less crosslinked structure may be deposited at a relatively high pressure. Increasing the frequency of power supply leads to a significant increase in the deposition rate. All deposited FC films with a uniform microstructure show the hydrophobic property. Decreasing the frequency of power supply or increasing the deposition pressure results in the deposition of FC films with the extremely low surface roughness. The relationship between plasma parameters and the analyzed properties of deposited FC films is discussed.

Cochlear implant has been successfully applied in clinic. Recent research indicates vision implants may be the potential way to restore sight for the blind. Here, principle and common structure of vision implants are introduced. Main vision approaches of retinal, optic nerve, and cortical prosthesis are reviewed. In our progress, electrical response at visual cortex is recorded, when penetrating electrodes stimulate rabbit optic nerve, vision implants based on optic nerve stimulator chip (ONSC) and Chipcon radio frequency (RF) chip are under developing. Despite several obstacles to overcome, promising results in animal and human experiments give scientists confidence that artificial vision implants will bring light to the blind in the near future.

Atmospheric-pressure N 2 , He, air, and O 2 microplasma arrays have been used to inactivate Escherichia coli cells suspended in aqueous solution. Measurements show that the efficiency of inactivation of E. coli cells is strongly dependent on the feed gases used, the plasma treatment time, and the discharge power. Compared to atmospheric-pressure N 2 and He microplasma arrays, air and O 2 microplasma arrays may be utilized to more efficiently kill E. coli cells in aqueous solution. The efficiencies of inactivation of E. coli cells in water can be well described by using the chemical reaction rate model, where reactive oxygen species play a crucial role in the inactivation process. Analysis indicates that plasma-generated reactive species can react with E. coli cells in water by direct or indirect interactions.

Atmospheric pressure plasma bullets or ionization waves have been generated in one long (Φ 2 mm × 100 mm) dielectric tube filled with He gas when a sinusoidal AC high-voltage with its frequencies of 9.0 kHz is applied between the tungsten pin electrodes. ICCD measurements show that the propagation of ionization waves in I, U and O tubes is anode-driven electrically, and the spatial and temporal development of ionization waves is strongly dependent on the He flow rate and applied voltage. Three stages are clearly observed during the propagation of ionization waves along the tube, and their propagation process is discussed based on the experimental results. The generation and propagation of ionization waves in the tube are affected by many physical processes, such as the drift motion of He+ ions or excited species, the distribution of plasma potential along the dielectric tube, the surface recombination of charged species, He+-induced electron emission from the pin cathode, and so on.

The cellular neural network (CNN) method is applied to solve the Pennes bioheat transfer equation, and its feasibility is demonstrated. Numerical solutions were obtained for a cellular neural network for a two-dimensional steady-state temperature field obtained from focused and unfocused ultrasound heat sources. Transient-state temperature fields were also studied and compared with experimental results obtained elsewhere. The cellular neural networks' key features of asynchronous parallel processing, continuous-time dynamics and local interaction enable real-time temperature field estimation for clinical hyperthermia.

In this paper, by using a high precision synchronization system, the ignition time, velocity, and propagation properties of the ionization waves (IWs) have been investigated in detail from the 1st high voltage (HV) pulse to the sequential ones over a large range of the pulse-off time. In order to clarify the effects of previous ionization and excitation on the IW propagation, the density of the residual charges are controlled by varying the pulse-off time from 199 μs to 15 μs. The results show that the formation and propagation of IWs can be strongly affected by previous discharge. For a longer pulse-off time (100 μs–190 μs), the propagation velocity of plasma bullets are decreased from the 1st to the 10th HV pulse, then increased after the 10th pulse, and finally become stable after about 500 pulses. When the pulse-off time is reduced to 15 μs, the propagation velocity of plasma bullets will rapidly increase and become stable after the 1st HV pulse. The ignition voltage is significantly reduced after the 1st HV pulse with the decrease in pulse-off time. Consequently, the generation and propagation of IWs in the tube are strongly affected by the accumulation of long-lived metastable helium (He) species and residual charges from previous discharges, which is important for understanding the plasma bullet behavior.

Our study has shown that the atmospheric-pressure He ionization waves (IWs) may be transferred from one dielectric tube (tube 1) to the other one (tube 2) via a floating metal wire. The propagation of IWs along the two tubes is not affected by the diameter of a floating metal wire, however, their propagation is strongly dependent on the length of a floating metal wire. The propagation of one IW along the tube 1 may result in the second IW propagating reversely inside the tube in vicinity of a floating metal wire, which keeps from their further propagation through the tube 1. After they merge together as one conduction channel inside the tube 1, the transferred plasma bullet starts to propagate along the tube 2. The propagation of transferred plasma bullets along the tube 2 is mainly determined by the capacitance and inductance effects, and their velocity and density can be controlled by the length of a floating metal wire.

Our research aims to develop a novel method for quantitative measurement of hCG concentration in human serum. Based on digital imaging processing technique, the relationship between hCG concentration and image information of reaction dot on hCG test sample can be built and be described as a standard curve. According to this standard curve, concentration of hCG sample can be measured. The image information of hCG test sample is captured by CCD mini-camera and is processed by digital signal processor (DSP). The sensitivity can be under 10mIU/ml. The high accuracy makes our system significantly potential application in clinical diagnosis.

Visually impaired people face many inconveniences because of the loss of vision. Therefore, scientists are trying to design various guidance systems for improving the lives of the blind. Based on sensory substitution, auditory guidance has become an interesting topic in the field of biomedical engineering. In this paper, we made a state-of-technique review of the auditory guidance system. Although there have been many technical challenges, the auditory guidance system would be a useful alternative for the visually impaired people.

Without visual information, the blind people live in various hardships with shopping, reading, finding objects and etc. Therefore, we developed a portable auditory guide system, called SoundView, for visually impaired people. This prototype system consists of a mini-CCD camera, a digital signal processing unit and an earphone, working with built-in customizable auditory coding algorithms. Employing environment understanding techniques, SoundView processes the images from a camera and detects objects tagged with barcodes. The recognized objects in the environment are then encoded into stereo speech signals for the blind though an earphone. The user would be able to recognize the type, motion state and location of the interested objects with the help of SoundView. Compared with other visual assistant techniques, SoundView is object-oriented and has the advantages of cheap cost, smaller size, light weight, low power consumption and easy customization.

More than 161 million people worldwide are suffering from ablepsia [1], and among them, ten million are blind result from the photoreceptor loss due to degenerative retinal diseases. For these patients, neural stimulating proved to be an effective method of rehabilitation. This method is based on conceive of substituting an artificial device for the defective photoreceptor in patients functionally [2]. Multi-channel neural stimulator is a part of the device. In the design of multi-channel neural stimulator, the kernel problems are concerning the output stimulating current. Micro, bipolar, and steady output current is required to protect guarantee safety and effectiveness of this stimulator [3]. Furthermore, a simple and tiny structure is essential for the stimulator to implanting into human bodies. This paper focused on the design of a circuit serves as the DA converter and stimulation generator, which is made up of a Micro Controller Unit (MCU), a Digital to Analog Convector (DAC) and Amplifiers. The results of simulation made by Multisim shows that this circuit can put out bi-phasic micro and steady current whose precision of the current is 5µA. The size of all the intraocular part of the whole device is 36mm×28mm.