Induced antibacterial capability of TiO2 coatings in visible light via nitrogen ion implantation

In order to enhance the antibacterial ability of titanium components,an antibacterial coating was fabricated on Ti surface by micro-arc oxidation(MAO)and further nitrogen plasma immersion ion implantation(N-PIII).The XPS spectra demonstrated that nitrogen was incorporated into TiO2 coatings by N-PIII and the nitrogen content on the surface of TiO2 coatings increased as the N-PIII time increased.Nitrogen-incorporated samples exhibited remarkably increased absorbance in the visible region and the light absorption edge of nitrogen-incorporated samples showed a redshift compared to MAO samples.Escherichia coli and Staphylococcus aureus were seeded on the samples to assess their antibacterial ability.The bacterial experiment demonstrated that nitrogen-incorporated TiO2 could effectively reduce the bacterial viability in visible light.Thus,the antibacterial TiO2 coatings fabricated by MAO and further N-PIII might have large potential in the medical and marine fields.

Improvement of tribological behavior of a Ti-Al-V alloy by nitrogen ion implantation

The tribological properties especially wear and hardness of a Ti-Al-V alloy with nitrogen implantation (energy 60 keV) were investigated. The implantation was carried out at fluences range from 1×1016 to 4×1017 ions/cm2. Glancing angle X-ray diffraction (GAXRD) and X-ray photoelectron spectroscopy (XPS) analyses were performed to obtain surface characterization of the implanted sample. The unimplanted and implanted samples were also annealed at 600 ℃ in order to understand the influence of annealing on the tribological properties of Ti-Al-V. The hardness shows significant improvement at the higher fluence. After annealing at 600 ℃, the friction coefficient exhibits a relative decrease for the nitrogen-implanted samples. In addition, the wear rates of the implanted samples exhibits a great decrease after annealing at 600 ℃. Nature of the surface and reason for the variation and improvement in wear resistance were discussed in detail.

The Effects of Low-Energy Nitrogen Ion Implantation on Pollen Exine Substructure and Pollen Germination of Cedrus deodara

The aim of this study is to investigate the biological effects of ion beams on pollen. Pollen grains of Cedrus deodara were implanted with 30 keV nitrogen ion beams at doses ranging from 1 × 10^15 ions/cm^2 to 15 × 10^15 ions/cm^2. The effects of N^＋ implantation on the pollen exine substructure were examined using an atomic force microscope （AFM）, and the structure and morphology of pollen and pollen tubes were observed using a laser scanning confocal microscope （LSCM）. AFM observations distinctly revealed the erosion of the pollen exine caused by N^＋ implantation in the micrometer to nanometer range. Typical results showed that the erosion degree was linearly proportional to the ion dose. Pollen germination experiments in vitro indicated that N^＋ implantation within a certain dose range increased the rate of pollen germination. The main abnormal phenomena in pollen tubes were also analyzed. Our results suggest that low energy ion implantation with suitable energy and dosage can be used to break the pollen wall to induce a transfer of exogenous DNA into the pollen without any damage to the cytoplasm and nuclei of the pollen. The present study suggests that a combination of the method of ion-beam-induced gene transfer and the pollen-tube pathway method （PTPW） would be a new plant transformation method.

SURFACE ANALYSES OF NITROGEN ION IMPLANTED Ti6Ai4V ALLOY

The techniques for surface analysis including AES,XPS and SIMS were employed to study the chemical composition and bond valence of nitrogen ion implanted surface of surgical implantation service alloy Ti6Al4V.The depth of implanted nitrogen ions and the sputtering rate of argon beams were determined using a profilometer.It was found that the combination of injected nitrogen ions with titanium resulted in the formation of hard TiN particles and the profile of nitrogen concentration approximately displayed gaussian distribution.The total depth of implanted nitrogen is about 350 nm and its maximum concentration appears in the depth of about 140 nm from the surface,in which the concentration ratio of nitrogen to titanium may be up to 1.1.

Mutation-Screening of Pleurotus Ferulae with High Temperature Tolerance by Nitrogen Ion Implantation

In order to obtain Pleurotus ferulae with high temperature tolerance, conidiophores of wild type strain ACK were implanted with nitrogen ions in energy of 5 -15 keV and dose of 1.5×10^15 - 1.5 × 10^16 cm^-2, and a mutant CGMCC1763 was isolated subsequently through thermotolerant screening method. It was found that during riper period the surface layer mycelium of the mutant in mushroom bag wasn＇t aging neither grew tegument even above 30℃. The mycelium endurable temperature of the mutant was increased by 5℃ compared to that of the wild type strain. The fruiting bodies growth temperature of the mutant was 18 -22℃ in daytime and 8 -14℃ at night. The highest growth temperature of fruiting bodies of the mutant was increased about 7℃ w.r.t, that of original strain. Through three generations investigations, it was found that the mutant CGMCC1763 was stable with high temperature tolerance.

Influence of Temperature on Nitrogen Ion Implantation of Ti6Al4V Alloy

in order to achieve increased layer thickness, and wearing resistance, enhanced ion implantation with nitrogen has been carried out at temperatures of 100, 200, 400, and 600℃ with a dose of 4x 1018 ions' cm-2. Using the Plasma Source ion Implantation (PSII) device, specimens of Ti6Al4V alloy were implanted at elevated temperatures, using the ion flux as the heating source. Auger Electron Spectroscopy (AES), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), micro-hardness measurements and pin-on-disk wearing tester were utilized to evaluate the surface property improvements. The thickness of the implanted layer increased by about an order of magnitude when the temperature was elevated from 100 to 600℃. Higher surface hardness and wearing resistance was also obtained in implantation under higher temperature. XRD image showed the presence of titanium nitrides on the implanted surface.

XPS INVESTIGATION OF NITROGEN IONS IMPLANTED INTO ALUMINUM ALLOY BY PLASMA BASED ION IMPLANTATION

Aluminum alloy 2024 has been implanted with nitrogen ions at various doses by plasma based ion implantation. The introduction of energetic ions causes structural change within the near surface region of the solid. The samples have been characterized by X-ray Photoelectron Spectroscopy at various depths. The chemical states of Al and N were identified by deconvolution of the recorded XPS spectra. After plasma based ion implanted nitrogen into aluminum, not only the AlN precipitates but also super saturated solution of nitrogen forms. The presence of aluminum in different chemical states is corresponding to Al, AlN and Al2O3. The majority of nitrogen is in the form of the supersaturated solution. With the increase of nitrogen dose, the amount of AlN precipitates increases.

The passivation mechanism of nitrogen ions on the gate leakage current of HfO_2/AlGaN/GaN MOS-HEMTs

In this paper, we systematically study the positive gate leakage current in AlGaN/GaN metal-oxide-semiconductor high electron-mobility transistors (MOS-HEMTs) with HfO 2 dielectric using atomic layer deposition (ALD). We observe that the incorporated nitrogen ions will improve the positive gate leakage current of devices obviously, but do not change the reverse gate leakage current. The passivation mechanism of nitrogen ions in oxygen vacancies in HfO 2 is studied by first-principles calculations. It is shown that the gap states of HfO 2 caused by oxygen vacancies increase the positive gate leakage current of MOS-HEMTs. Nitrogen ions passivate the gap states of HfO 2 and decrease the positive gate leakage current but do not effect the reverse gate leakage current.

Effects of nitrogen ion implantation on lily pollen germination and the distribution of the actin cytoskeleton during pollen germination

The effects of low energy nitrogen ion implantation on lily (Lilium davidii Duch.) pollen germination and the distribution of the actin cytoskeleton during pollen germination have been studied. Preliminary results showed that the ratio of pollen germination increased from (16.0±1.6)% to (27.0±2.1)% when implanted with nitrogen ions by 100 keV and a dose of 1013 ions/cm2. Further experiments were performed by staining the actin filaments in pollen with rhodamine-phalloidin and detected by using laser confocol microscopy. After hydration for 10 h, the actin filaments in ion implanted pollen grains tended to form thick bundles oriented in parallel or ring shape at the germinal furrow, indicating that the effect of nitrogen ion implantation on the germination of pollen might be mediated by reorganization of the actin cytoskeleton.

Effects of nitrogen ion implantation on Ca^(2+) concentration and membrane potential of pollen cell

The effects of low energy nitrogen ion implantation on Ca2+ concentration and membrane potential of illy (Mum davidii Duch) pollen cell have been studied. The results showed that the Ca2+ concentration was increased when pollen grain was implanted by nitrogen ion with energy 100 keV and dose 1013 ions/cm2. However, the increase of Ca2+ concentration was partly inhibited by the addition of Ca2+ channel inhibitor depending on dose. And nitrogen ion implantation caused depolarization of pollen cell membrane potential. In other words, membrane potential was increased, but the effect decreased by adding Ca2+ channel inhibitor. However, it was still significantly higher than the membrane potential of control cells. It was indicated that the depolarization of cell membrane potential opened the calcium channel on the membrane that caused the increasing of intracel-lular calcium concentration. This might be an earlier step of the effect of low energy nitrogen ion implantation on pollen germination.

MATHEMATICAL MODELS OF NITROGEN CONCENTRATION PROFILE OF ION NITRIDED LAYERS AND COMPUTER SIMULATION

The mathematical models of the kinetics of the layer growth at different ion nitriding condi- tions of armco iron.steels 45,40Cr,42CrMo and 38CrMoAl have been established.Based on these models the expression of nitrogen concentration profile of ion nitrided layers have been deduced with profile simulating method.They are C_=C_(min)^+(P_4)/(ξ_1-x)+(P_5)/(ξ_(10)~2)(ξ_1-x)~2 C_(γ′)=C_(min)^(γ′)+(P_1)/(ξ_(21))(ξ_2-x)+(P_2)/(ξ_(21)~2)(ξ_2-x)~2 C_α=C_(min)~α+(C_(33))/(C_(33))/(ξ_(32))(ξ_3-x)~3 Using these models,the kinetics of layer growth and the nitrogen concentration profile of ion nitrided layers were sinulated on Apple-Ⅱ computer.Results show that the simulated curves coincide quite well with the experimental data.

Nitrogen-Doped TiO_2–C Composite Nanofibers with High-Capacity and Long-Cycle Life as Anode Materials for Sodium-Ion Batteries

Nitrogen-doped TiO_2–C composite nanofibers(TiO_2/N–C NFs) were manufactured by a convenient and green electrospinning technique in which urea acted as both the nitrogen source and a pore-forming agent. The TiO_2/N–C NFs exhibit a large specific surface area(213.04 m^2 g^(-1)) and a suitable nitrogen content(5.37 wt%). The large specific surface area can increase the contribution of the extrinsic pseudocapacitance, which greatly enhances the rate capability. Further, the diffusion coefficient of sodium ions(DNa_+) could be greatly improved by the incorporation of nitrogen atoms. Thus, the TiO_2/N–C NFs display excellent electrochemical properties in Na-ion batteries. A TiO_2/N–C NF anode delivers a high reversible discharge capacity of 265.8 mAh g^(-1) at 0.05 A g^(-1) and an outstanding long cycling performance even at a high current density(118.1 m Ah g^(-1)) with almost no capacity decay at 5 A g^(-1) over 2000 cycles. Therefore, this work sheds light on the application of TiO_2-based materials in sodium-ion batteries.

Multireference calculation of lifetime of A^2Π_u state in nitrogen-molecule cation

This paper utilizes multireference configuration interaction theory to calculate the lifetime of A2Пu state for nitrogen molecular ion N2＋. It obtains the transition moment function for A2Пu →X2∑g＋, Franck-Condon factors between vibrational levels of the two states. The calculated lifetimes are 16.81, 14.62, 13.10, 12.18, 11.40, and 11.64 its for v′ = 0, 1, 2, 3, 4, 5 vibrational levels of A2Пu state, respectively, which are in excellent agreement with available experimental values.

On the Plasma (ion) Carburized Layer of High Nitrogen Austenitic Stainless Steel

The manganese concentration of austenitic stainless steel decreases from the inner layer towards the surface of the plasma (ion) carburized layer due to the evaporation of manganese from the specimen surface. The carbon concentration in the carburized layer is influenced by alloyed elements such as Cr, Ni, Si, and Mo, as well as Nitrogen. This study examined the effects of nitrogen on the properties of the carburized layer of high nitrogen stainless steel. Plasma (ion) carburizing was carried out for 14.4 ks at 1303 K in an atmosphere of CH4+H2 gas mixtures under a pressure of 350 Pa. The plasma carburized layer of the high nitrogen stainless steel was thinner than that of an austentric stainless steel containing no nitrogen. This suggested that the nitrogen raised the activity of carbon in the plasma carburized layer, GDOES measurement indicated that the nitrogen level in the layer did not vary after plasma (ion) carburizing.

Biological effects of implantation and penetration of nitrogenion beams on wheat seeds

ＢｉｏｌｏｇｉｃａｌｅｆｆｅｃｔｓｏｆｉｍｐｌａｎｔａｔｉｏｎａｎｄｐｅｎｅｔｒａｔｉｏｎｏｆｎｉｔｒｏｇｅｎｉｏｎｂｅａｍｓｏｎｗｈｅａｔｓｅｅｄｓＬｉＷｅｎ－Ｊｉａｎ（李文建），ＷｅｉＺｅｎｇ－Ｑｕａｎ（卫增泉），ＸｉｅＨｏｎｇ－Ｍｅｉ（颉红梅）...

Forbidden transition properties of fine-structure 2p^3 ~4S_(3/2)–2p^3 ~2D_(3/2,5/2) for nitrogen-like ions

Based on relativistic wave functions from multiconfiguration Dirac-Hartree-Fock and configuration interaction cal- culations, E2 and M1 transition probabilities of 2p3 4S3/2-2p3 2D3/2,5/2 are investigated in the nitrogen-like sequence with 7 〈 Z 〈 16. The contributions of the electron correlations, Breit interaction, and the quantum electrodynamic （QED） effects on the transition properties are analyzed. The present results can be used for diagnosing plasma. In addition, several N-like ions can also be recommended as a promising candidate for a highly charged ion （HCI） clock with a quality factor （Q） of trnnsition as hitch as 1020.

Structure and visible photocatalytic activity of nitrogen-doped meso-porous TiO_2 layer on Ti6Al4V substrate by plasma-based ion implantation

The nitrogen-doped porous TiO2 layer on Ti6Al4V substrate was fabricated by plasma-based ion implantation of He, O and N. In order to increase the photodegradation efficiency of TiO2 layer, two methods were used in the process by forming mesopores to increase the specific surface area and by nitrogen doping to increase visible light absorption. Importantly, TiO2 formation, porosity architectures and nitrogen doping can be performed by implantation of He, O and N in one step. After implantation, annealing at 650 ℃ leads to a mixing phase of anatase with a little rutile in the implanted layer. By removing the near surface compact layer using argon ion sputtering, the meso-porous structure was exposed on surfaces. Nitrogen doping enlarges the photo-response region of visible light. Moreover, the nitrogen dose of 8×1015 ion/cm2 induces a stronger visible light absorption. The photodegradation of rhodamine B solution with visible light sources indicates that the mesopores on surfaces and nitrogen doping contribute to an apparent increase of photocatalysis efficiency.

Effects of Cross Linking on the Chromatographic Nitrogen Isotope Separation

The effects of cross linking with porous cation exchange resin were studied for nitrogen isotope separation. The displacement chromatography was conducted by the resin with cross linking rang from 20% to 40%. A sharp adsorbed ammonium band was maintained for each operation. Enriched 15N isotopes with 0.93% were obtained by 20% cross linking resin and two meters chromatographic operation which started from the natural abundance of ammonium molecule. The effect of cross linking percentage on the height equivalent to a theoretical plate (HETP) was evaluated in the present work and the HETP value is proportional to the cross linking percentage. HETP value of 0.036 cm was obtained at the present system by using 20% cross linking resin.

Nitrogen Deposition Via N^+ Implantation:Implications for Primordial Amino Acids Synthesis Revisited

In this paper amino acids synthesis in aqueous solution induced by ion implantation, which was possibly ubiquitous on primitive Earth, is investigated. As a discharge using a graphite rod as the anode under a nitrogen atmosphere was performed against ammonia water, it was found that three kinds of amino acids were produced. They were glycine, serine and alanine. By introducing ion implantation into the carboxylate solution, ammonia and amino acids were also formed via nitrogen deposition/fixation. Another isotopic experiment showed that both OH and H radicals played a crucial role in the arc-discharge-promoted reactions in aqueous solution Therefore, we believe that the impact of ions in the original atmospheric conditions might have functioned as a promoter in the chemical origin and evolution of life.

Stabilising Cobalt Sulphide Nanocapsules with Nitrogen-Doped Carbon for High-Performance Sodium-Ion Storage

Conversion-type anode materials with a high charge storage capability generally su er from large volume expansion, poor electron conductivity, and sluggish metal ion transport kinetics. The electrode material described in this paper, namely cobalt sulphide nanoparticles encapsulated in carbon cages(Co9S8@NC), can circumvent these problems. This electrode material exhibited a reversible sodium-ion storage capacity of 705 mAh g^-1 at 100 mA g^-1 with an extraordinary rate capability and good cycling stability. Mechanistic study using the in situ transmission electron microscope technique revealed that the volumetric expansion of the Co9S8 nanoparticles is bu ered by the carbon cages, enabling a stable electrode–electrolyte interface. In addition, the carbon shell with high-content doped nitrogen significantly enhances the electron conductivity of the Co9S8@NC electrode material and provides doping-induced active sites to accommodate sodium ions. By integrating the Co9S8@NC as negative electrode with a cellulose-derived porous hard carbon/graphene oxide composite as positive electrode and 1 M NaPF6 in diglyme as the electrolyte, the sodium-ion capacitor full cell can achieve energy densities of 101.4 and 45.8 Wh kg^-1 at power densities of 200 and 10,000 W kg^-1, respectively.