Ma Teng-Cai

Stimulating Effects of Seed Treatment by Magnetized Plasma on Tomato Growth and Yield

Tomato seeds (Lycopersicon esculentum L. Mill. cv. zhongshu No. 6) were treated by magnetized plasma before being sown to investigate its effect on the growth and yield of tomatoes. Biochemical analysis showed that dehydrogenase activity increased with the increase of the current but decreased when the current was higher than 1.5 A. The activities of peroxidase (POD) isoenzyme changed in the same pattern. There was no difference in germination percentage between treatments and control, which were carried out in laboratory conditions. However, significant (α = 0.01) difference was observed in germination percentage in the pot experiment. In the pot experiment, the sprouting rate for the treatment with a 1.5 A current was 32.75%, whereas the untreated was only 4.75% on the eleventh day. Germination time is more than one day earlier than the control. The 1.5 A treatment increased the tomato yield by 20.7%.

Plasma Catalytic Synthesis of Silver Nanoparticles

We present the experimental results of plasma catalytic synthesis of colloidal silver nanoparticles, using AgNO3 as the precursor, ethanol as the solvent and reducing agent, and poly vinyl pyrrolidone (PVP) as the macromolecular surfactant. The plasma is generated by an atmospheric argon dielectric barrier discharge jet. Silver nanoparticles are produced instantly once the plasma is ignited. The system is not heated so it is necessary to use traditional chemical methods. The samples are characterized by UV-visible absorbance and transmission electron microscopy. For glow discharge mode no obvious silver nanoparticles are observed. For low voltage filamentary streamer discharge mode a lot of silver nanoparticles with the mean diameter of ~3.5 nm are generated and a further increase of the voltage causes the occurrence of agglomeration.

Fe Nanoparticle Production by an Atmospheric Cold Plasma Jet

We present a simple method of producing Fe nanoparticles based on the dissociation of ferrocene by a simple single electrode atmospheric cold argon plasma jet. The system is driven by a sinusoidal ac-supply with a peak voltage of 0–30 kV and a frequency of 50 kHz. The average size of iron nanoparticles analyzed by scanning electron microscopy is about 10–30 nm for the gas phase samples, and 30–100 nm for the liquid phase samples. The method should be competitive due to its simplicity and low cost.

Two-dimensional numerical research on effects of titanium target bombarded by TEMP II accelerator

Two-dimensional numerical research has been carried out on the ablation effects of titanium target irradiated by intense pulsed ion beam (IPIB) generated by TEMP II accelerator. Temporal and spatial evolution of the ablation process of the target during a pulse time has been simulated. We have come to the conclusion that the melting and evaporating process begin from the surface and the target is ablated layer by layer when the target is irradiated by the IPIB. Meanwhile, we also obtained the result that the average ablation velocity in target central region is about 10 m/s, which is far less than the ejection velocity of the plume plasma formed by irradiation. Different effects have been compared to the different ratio of the ions and different energy density of IPIB while the target is irradiated by pulsed beams.

Plasma enhanced direct current planar magnetron sputtering technique employing a twinned microwave electron cyclotron resonance plasma source

The dc discharge of a planar magnetron was enhanced by a twinned microwave electron cyclotron resonance plasma source. The magnetic cusp geometry formed in the processing chamber was used for plasma confinement. The sputtering discharge characteristics were investigated and a combined mode of voltage and current was observed at a pressure as low as 0.007 Pa. Carbon–nitride thin films were synthesized using this method. Characterization of the films show that deposition rate was high, the films were composed of a single amorphous carbon nitride phase with N/C ratio close to that of C3N4, and the bonding was mainly of C–N type.

Cubic-BN-Like Structure of B-C-N Films Synthesized by Plasma Source Ion Nitriding

Plasma source ion nitriding has emerged as a low-temperature, low-pressure nitriding approach for implanting nitrogen ions and then diffusing them into bulk materials. The ion-plating B-C films were nitrided to synthesize B-C-N films at a nitriding temperature from 300 to 500° C. The x-ray photoelectron spectroscopy and diffuse reflectance Fourier transform infrared spectra analyses showed that the amorphous B-C-N films synthesized at 500° C are composed mainly of cubic-BN-like and hexagonal-BN-like plain microdomains. The higher nitriding temperature contributes to the formation of cubic-BN-like B-C-N structure in the B-C-N films.

Computer simulation of multicomponent ion beam enhanced deposition of (TiMo) N films

Abstract A Monte Carlo computer simulation code has been developed to describe the behavior of incident particles and the growth of (TiMo) N films in the multicomponent ion beam enhanced deposition process, which combines bombardment with a multicomponent ion beam of N + +Mo + and sputter deposition of a Ti film. The film composition profile and intermixed layer between the substrate and the film were studied using a computer simulation method. It is shown that Mo ion implantation has a stronger mixing effect in the film–substrate interface than does N ion implantation. The N profile of the computer simulation conforms to that of the Auger electron spectroscopy results.

Deposition of diamond-like carbon films by high-intensity pulsed ion beam ablation at various substrate temperatures

Diamond-like carbon (DLC) films have been deposited on to Si substrates at substrate temperatures from 25°C to 400°C by a high-intensity pulsed-ion-beam (HIPIB) ablation deposition technique. The formation of DLC is confirmed by Raman spectroscopy. According to an x-ray photoelectron spectroscopy analysis, the concentration of sp3 carbon in the films is about 40% when the substrate temperature is below 300°C. With increasing substrate temperature from 25°C to 400°C, the concentration of sp3 carbon decreases from 43% to 8%. In other words, sp3 carbon is graphitized into sp2 carbon when the substrate temperature is above 300°C. The results of x-ray diffraction and atomic force microscopy show that, with increasing the substrate temperature, the surface roughness and the friction coefficient increase, and the microhardness and the residual stress of the films decrease.

Diffuse Reflectance Fourier Transform Infrared Spectrometry of BN Films Deposited on Steels by Remote Microwave Plasma CVD from Borazine

The diffuse reflectance Fourier transform infrared spectra of the boron nitride (BN) films deposited on steels by remote microwave plasma chemical vapour deposition (CVD) from borazine with nitrogen, hydrogen and argon were investigated in the wavenumber range of 400-4000 cm-1. It was found that the cubic BN formation depends on production of the intermediate species of cyclotriborazane ((BH2NH2)3) and its dehydrogenation. The structural bonds of cyclotriborazane are similar to that of cubic BN. Optimum conditions for deposited BN films were found to be the borazine-nitrogen mixture at the substrate temperature of 550°C. The BN films were a mixture of crystalline cubic BN accounting for the major content and hexagonal BN with relatively low hydrogen content.

RC-Coupled Atmospheric Glow Discharge in Air

Resistance and capacity-coupled glow discharge (RCCGD) is a new method to produce atmospheric pressure glow discharge in air. In RCCGD, each electrode is connected with both a resistor R and a capacitor C. The R and C can provide a negative feedback to prevent the transition from glow to spark discharge. The influence of coupled resistance, coupled capacity, inter-electrode gap and power source frequency on the discharge is studied and discussed.