Biological Effects of Stevia rebaudianum Induced by Carbon Ion Implantation

The biological effects during seed germination were investigated after the dry seeds of Stevia rebaudianum Bertoni were implanted with carbon ion beam of 75 keV and 10 14 ions/cm 2. The results showed that the germination rate of carbon ion implanted seeds was slightly higher than that of the control, but the survival rate of the treated seedlings, on the contrary, was lower than that of the control (P<0.02), while the height of the treated seedlings was significantly higher than that of the control (P<0.01). On the 4th day after germination, the leaf cell wall in the treated group was thick, some high electron_dense substance deposited in the enlarged plasmodesma; Cell membrane creased with high electron_dense granules deposited on it. The plasma membrane protruded towards cell wall, and the granules shifted via plasmodesma or deposited onto cell wall. These phenomena may be related to the conveyance of implanted ions across cell wall, or be related to the accumulation of callose. In addition, the implantation of carbon ions could increase the lamellae of the chloroplast and cause high development of the chloroplast which sometimes contained two plastid centers in an individual chloroplast. Also, the highly developed cristae, abundant mitochondria and typical crystalloid structure in microbody could be found. All these results indicated that the anabolic and catabolic activities in the seedlings implanted with carbon ions before germination were obviously more active than those in the controls.

Enhanced Photocatalytic Activity of C-TiO_2 Thin Films Prepared by Magnetron Sputtering and Post-carbon Ion Implantation

TiO2 thin films were fabricated by RF magnetron sputtering on titanium substrates and then implanted with different amounts of carbon. The microstructure, valence states and optical characteristics of each sample were investigated by X-ray diffraction, X-ray photoelectron spectroscopy and UV-vis diffuse reflection spectroscopy. Photoelectric property was evaluated under visible light using a xenon lamp as illuminant. The experimental results indicate that the implanting carbon concentration has a significant infl uence on film＇s micro structure and element valence states. The dominant valence states of carbon vary as carbon content increases. Carbon ion implantation remarkably enhances the current density and photocatalytic capability of TiO2 thin films. The optimized implanting content is 9.83×10^17 ion/cm^2, which gives rise to a 150% increased photocurrent and degradation rate.

Biological Effects of Sunflower Seeds Implanted by Carbon Ion

[ Objective ] This study aimed to investigate the effects of carbon ion implantation and implantation times on growth and genetic variation of sunflowers. [ Method] Carbon ions were implanted into Bakui 138, Bakui i36 and Bakui 118 seeds at dose of 5 - 10is C/cm2, before they were planted. Their Fl-generation seeds were irradiated again. Seeds of the both generations were planted and the growth d the seedlings was observed in field tests. Finally, their genetic variation was analyzed through RAPD. [ Result] The germination rate and several agronomic traits like plant height, stem diameter, leaf number and yields of Bakui 138 of once-irradiated group were significantly improved, while that of twice-irradiated group showed opposite trend. The variation of Bakui 136 and Bakui 118 was insig- nificant. At the molecular level, the genetic distance with the control group of once and twice-irradiated groups was 0. 111 1, 0. 108 7 in Bakui 138; 0. 068 O, O. 030 3 in Bakui 136 and 0.062 5,0.043 5 in Bakui 118. [Conclusion] Carbon ion implantation had a significant effect on the growth and development of Bakui 138, and the effect varied with irradiation times. Moreover, it caused genomic variation in the three sunflower cuhivars.

Surface Analysis of ZIRLO Alloy Implanted with Carbon

ZIRLO alloy specimens were implanted with carbon ions with fluence range from 1×10 16 to 1×10 18ions·cm -2, using a MEVVA source at an extraction voltage of 40 kV at maximum temperature of 380 ℃. The surfaces of the implanted samples were then analyzed and the TRIM 96 computer code was used to simulate the depth distribution of carbon. The valences of elements in the implanted surface of ZIRLO alloy were analyzed by X-ray photoemission spectroscopy (XPS); and then the depth distributions of the elements on the surface of the samples were obtained by Auger electron spectroscopy (AES). Scanning electron microscopy (SEM) was used to examine the micro-morphology of implanted samples. Glancing angle X-ray diffraction (GAXRD) at 0.30 incident angles was employed to examine the phase transformations of implanted samples. It shows that the as-received ZIRLO alloy is mainly composed of hexagonal alpha zirconium, as for implanted samples, there appeared hexagonal zirconia (H-ZrO_ 0.35) and sigma zirconium carbide (δ-Zr_3C_2), and the δ-Zr_3C_2 increased when increasing the fluence. When the fluence reached 1×10 18 ions·cm -2, the concentration of δ-Zr_3C_2 is the maximum in all the samples. The micro-morphology of implanted samples are similar, there are many pits with diameters ranging from 1 to 3 μm on the implanted surfaces.