Ion implantation induced damage in GaSb and its removal by rapid thermal annealing(RTA)have been investigated by Raman spectroscopy.The evolution of the Raman modes as a function of implantation fluence,annealing temp...Ion implantation induced damage in GaSb and its removal by rapid thermal annealing(RTA)have been investigated by Raman spectroscopy.The evolution of the Raman modes as a function of implantation fluence,annealing temperature and time has been analyzed.Results indicate that a lattice quality that is close to as-grown GaSb has been obtained by annealing the implanted samples at 500℃for 45 s.However,consequent surface analyses by scanning electron microscope(SEM)and atomic force microscope(AFM)show that a heavily perturbed layer contains voids due to the outdifiusion of Sb atoms on the surface remains.Mechanism of the damage recovery and the structure of the implanted layer are discussed based on the experimental results.展开更多
The research on plasma immersion ion implantation has been conducted for a little over ten years. Much is needed to investigate including processing technlogy, plasma sheath dynamics, interaction of plasma and surface...The research on plasma immersion ion implantation has been conducted for a little over ten years. Much is needed to investigate including processing technlogy, plasma sheath dynamics, interaction of plasma and surface, etc. Of the processing methods elavated temperature technique is usually used in PIII to produce a thick modified layer by means of the thermal diffusion. Meanwhile plasma ion heating is more recently developed by Ronghua Wei et al[1]. Therefore the temeperature is a critical parameter in plasma ion processing. In this paper we present the theoretical model and analysize the effect of imlantation voltage, plasma density, ion mass,etc on the temperature rise.展开更多
The tribological behaviors of TiN coating and TiN+TiC+Ti(C, N)/diamond like carbon (DLC), TiN/DLC, TiC/DLC multilayers on Ti 6Al 4V alloy prepared by plasma based ion implantation (PBII) were compared. Under the test ...The tribological behaviors of TiN coating and TiN+TiC+Ti(C, N)/diamond like carbon (DLC), TiN/DLC, TiC/DLC multilayers on Ti 6Al 4V alloy prepared by plasma based ion implantation (PBII) were compared. Under the test conditions of counterbody AISI 52100, load 1 N and speed 0.05 m/s, the tribological properties of the alloy are improved by these films in the order of TiN, TiC/DLC, TiN/DLC and TiN+TiC+Ti(C,N)/DLC. Tribological behavior is affected by the conditions of surface modification and triboexperiments. The appearance of “peaks” in the wear dynamic resistance profiles may be due or correspond to the process of formation and breaking apart of transition films. The breakthrough of the DLC coated samples may start from partially wearing out, and end with joining piece dilamination. There are transition films on all counterbodies AISI 52100. When AISI 52100 counterbody is changed to Ti 6Al 4V, the wear of most modified samples is changed from only disc to both disc and ball abrasive dominated.展开更多
Bacillus megaterium BM302 bred by ion-beam implantation produces L-sorbose dehydrogenase accelerative protein (SAP) to accelerate the activity of L-sorbose dehydrogenase (SDH) of Gluconobacter oxydans in the 2-ket...Bacillus megaterium BM302 bred by ion-beam implantation produces L-sorbose dehydrogenase accelerative protein (SAP) to accelerate the activity of L-sorbose dehydrogenase (SDH) of Gluconobacter oxydans in the 2-keto-L-gulonic acid (2KLG) fermentation from L-sorbose by the mixed culture of B. megaterium BM302 and G. oxydans. The SAP purified by three chromatographic steps gave 35-fold purification with a yield of 13% and a specific activity of 5.21 units/mg protein. The molecular weight of the purified SAP was about 58 kDa. The SDH accelerative activity of SAP at pH 7 and 50℃ was the highest. Additionally, it retained 60% activity at a pH range of 6.5 ~ 10 and was stable at 20℃ ~ 60℃. After 0.32-unit SAP was added to the single cultured G. oxydans strains, the SDH activity was apparently accelerated and the 2KLG yield of GO29, GO112, GO and GI13 was enhanced 2.1, 3.3, 3.5 and 2.9 folds respectively over that of the strains without the addition of SAP.展开更多
As a new mutagenetic method, low-energy ion implantation has been used widely in many research areas in recent years. In order to obtain some industrial strains with high xylanase yield, the wild type strain Aspergill...As a new mutagenetic method, low-energy ion implantation has been used widely in many research areas in recent years. In order to obtain some industrial strains with high xylanase yield, the wild type strain Aspergillus niger A3 was mutated by means of nitrogen ions implantation (10 keV, 2.6× 10^14 ~ 1.56 × 10^15 ions/cm^2) and a mutant N212 was isolated subsequently. However, it was found that the initial screening means of the high-yielding xylanase strains such as transparent halos was unfit for first screening. Compared with that of the wild type strain, xylanase production of the mutant N212 was increased from 320 IU/ml to 610 IU/ml, and the optimum fermentation temperature was increased from 28 ℃ to 30 ℃.展开更多
In order to generate a mutant of Bacillus subtilis with enhanced surface activity through low energy nitrogen ion beam implantation, the effects of energy and dose of ions implanted were studied. The morphological cha...In order to generate a mutant of Bacillus subtilis with enhanced surface activity through low energy nitrogen ion beam implantation, the effects of energy and dose of ions implanted were studied. The morphological changes in the bacteria were observed by scanning electron microscope (SEM). The optimum condition of ions implantation, 20 keV of energy and 2.6 × 10^15N^+/cm^2 in dose, was determined. A mutant, B.s-E-8 was obtained, whose surface activity of 50-fold and 100-fold diluted cell-free Landy medium was as 5.6-fold and 17.4-fold as the wild strain. The microbial growth and biosurfactant production of both the mutant and the wild strain were compared. After purified by ultrafiltration and SOURCE 15PHE, the biosurfactant was determined to be a complex of surfactin family through analysis of electrospray ionization mass spectrum (ESI/MS) and there was an interesting finding that after the ion beam implantation the intensities of the components were different from the wild type strain.展开更多
Magnesium alloys have a wide range of applications in industry; however, their corrosion resistance, wear resistance, and hardness are rather poor, which limit their applications. Ti ion was implanted into the AZ31 ma...Magnesium alloys have a wide range of applications in industry; however, their corrosion resistance, wear resistance, and hardness are rather poor, which limit their applications. Ti ion was implanted into the AZ31 magnesium alloy surface by metal vapor vacuum arc (MEVVA) implanter. This metal arc ion source has a broad beam and high current capabilities. The implantation energy was fixed at 45 keV and the dose was at 9×10^17 cm^-2. Through ion implantation, Ti ion implantation layer with approximately 900 um in thickness was directly formed on the surface of AZ31 magnesium alloy, by which its surface property greatly improved. The chemical states of some typical elements of the ion implantation layer were analyzed by means of X-ray photoelectron spectroscopy (XPS), while the cross sectional morphology of the ion implantation layer and the phase structure were observed by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The property of corrosion resistance of the Ti ion implanted layer was studied by the CS300P electrochemistry corrosion workstation in 3.5% NaCl solution. The results showed that the property of corrosion resistance was enhanced remarkably, while the corrosion velocity was obviously slowed down.展开更多
With ion implantation (N+, energy 10 keV and dosage 1.56×1015 N+cm-2), a high xylanase-producing strain Aspergillus niger N212 was selected. Based on an orthogonal experiment, an optimal fermentation condition wa...With ion implantation (N+, energy 10 keV and dosage 1.56×1015 N+cm-2), a high xylanase-producing strain Aspergillus niger N212 was selected. Based on an orthogonal experiment, an optimal fermentation condition was designed for this high-yield strain. The suitable medium was composed of 8% corncob; 1.0% wheat bran; 0.1%TWEEN20; 0.5% (NH4)2SO4; 0.5%NaNO3; 0.5%FeSO4, 7.5 × 10-4; MnSO4·H2O, 2.5 × 10-4; ZnSO4, 2.0 × 10-4; CoCl2, 3.0 × 10-4. At present, under our experiment condition, xylanase activity of Aspergillus niger N212 reached a level of 600 IU/ml, almost increased by 100% in xylanase production and the time of yielding xylanase was largely reduced to 12 h at 28℃.展开更多
This paper reports that ion implantation to a dose of 1 ×10^17 ions/cm^2 was performed on c-axis-orientated ZnO thin films deposited on (0001) sapphire substrates by the sol-gel technique. After ion implantatio...This paper reports that ion implantation to a dose of 1 ×10^17 ions/cm^2 was performed on c-axis-orientated ZnO thin films deposited on (0001) sapphire substrates by the sol-gel technique. After ion implantation, the as-implanted ZnO films were annealed in argon ambient at different temperatures from 600 - 900 ℃. The effects of ion implantation and post-implantation annealing on the structural and optical properties of the ZnO films were investigated by x-ray diffraction (XRD), photoluminescence (PL). It was found that the intensities of (002) peak and near band edge (NBE) exitonic ultraviolet emission increased with increasing annealing temperature from 600- 900 ℃. The defect related deep level emission (DLE) firstly increased with increasing annealing temperature from 600 - 750 ℃, and then decreased quickly with increasing annealing temperature. The recovery of the intensities of NBE and DLE occurs at ~850℃ and ~750℃ respectively. The relative PL intensity ratio of NBE to DLE showed that the quality of ZnO films increased continuously with increasing annealing temperature from 600 - 900 ℃.展开更多
Plasma-immersion ion implantation (PIII) is a technique for implanting ions into conducting, semiconducting and insulating objects. In PIII, the object being treated is immersed in a plasma and pulsed to a large negat...Plasma-immersion ion implantation (PIII) is a technique for implanting ions into conducting, semiconducting and insulating objects. In PIII, the object being treated is immersed in a plasma and pulsed to a large negative voltage (=-1 to-100 kV). The resulting sheath expands into the ambient plasma, extracting ions and accelerating them to the target. PIII has advantages over beam-line implantation in that large surfaces can be rapidly implanted, irregularly-shaped objects can be implanted without target manipulation, and surfaces that are not line-of-sight accessible can be treated. A two-dimensional, self-consistent model of plasma dynamics appropriate for PIII is described. The model is a hybrid, with Boltzmann electrons and kinetic ions, where the ion Vlasov equation is solved using the particle-in-cell (PIC) method. Solutions of the model give the time dependence of the ion flux, energy and impact angle at the target surface, together with the evolution of the sheath.展开更多
Low-energy ion implantation, as a new technology to produce mutation in plant breeding, has been widely applied in agriculture in China. But so far there is a little understanding of the underlying mechanisms responsi...Low-energy ion implantation, as a new technology to produce mutation in plant breeding, has been widely applied in agriculture in China. But so far there is a little understanding of the underlying mechanisms responsible for its biological effects at the cellular level. Here we report the biological effects of a nitrogen ion beams of 30 keV on the pollen grains of Pinus thunbergii Parl. In general, ion implantation inhibited pollen germination. The dose-response curve presented a particular saddle-like pattern. Ion implantation also changed the dimension of the elongated tubes and significantly induced tip swelling. Confocal microscopy indicated that the pollen tube tips in P. thunbergii contained an enriched network of microtubules. Ion implantation led to the disruption of microtubules especially in swollen tips. Treatment with colchicine demonstrated that tip swelling was caused by the disruption of microtubules in the tip, indicating a unique role for microtubules in maintaining the tip integrality of the pollen tube in conifer. Our results suggest that ion implantation induce the disruption of microtubule organization in pollen and pollen tubes and subsequently cause morphological abnormalities in the pollen tubes. This study may provide a clue for further investigation on the interaction between low-energy ion beams and pollen tube growth.展开更多
Plasma immersion ion implantation (PIII), unrestricted by sight-light process, is considered a proper method for inner surface strengthening. Two-dimensional simulation oj inner surface PIII process of cylindrical bo...Plasma immersion ion implantation (PIII), unrestricted by sight-light process, is considered a proper method for inner surface strengthening. Two-dimensional simulation oj inner surface PIII process of cylindrical bores were carried out in this paper using cold plasma fluid model, and influence of the bore's dimension on impact energy, retained dose and uniformity of inner surface were investigated.展开更多
The surface properties of Ti-6Al-4V alloy coated with titanium nitride, TiN+TiC+Ti(C,N)/DLC (diamond like carbon), TiN/DLC and TiC/DLC films by plasma-based ion implantation (PBII) with nitrogen, PBII with nitrogen th...The surface properties of Ti-6Al-4V alloy coated with titanium nitride, TiN+TiC+Ti(C,N)/DLC (diamond like carbon), TiN/DLC and TiC/DLC films by plasma-based ion implantation (PBII) with nitrogen, PBII with nitrogen then acetylene, PBII with nitrogen then glow discharge deposition with acetylene plus hydrogen and PBII with acetylene then glow discharge deposition with acetylene plus hydrogen respectively were studied. The corresponding films are found getting dimmer, showing light gold or gold, smoky color (uneven), light red in black (uneven), and graphite black separately. The corresponding film resistivities are given. Antioxidation ability of the titanium nitride film is poor, while the existence of carbon (or carbide) improves the antioxidation ability of the films. Having undergone excellent intermediate transitional region of nitrogen and carbon implantation, the top DLC layer of the TiN+TiC+Ti(C,N)/DLC multilayer are formed after the carbon implantation has the best adhesion with the substrate among all the multilayers. Although microhardness of the samples increases in the order of coatings of titanium nitride, TiN/DLC, TiN+TiC+Ti(C,N)/DLC and TiC/DLC, the TiN/DLC and TiC/DLC multilayers have greater brittleness as compared with other films.展开更多
Ion implantation is a powerful method for fabricating nanoparticles in dielectric. For the actual application of nanoparticle composites, a careful control of nanoparticles has to be achieved. In this letter, the size...Ion implantation is a powerful method for fabricating nanoparticles in dielectric. For the actual application of nanoparticle composites, a careful control of nanoparticles has to be achieved. In this letter, the size, distribution and morphology of Ag nanoparticles are controlled by controlling the ion current density, ion implantation sequence and ion irradiation dose. Single layer Ag nanoparticles are formed by Ag^+ ion implantation at current density of 2.5 μ^A/cm2. By Ag and Cu ions sequential implantation, the size of single layer Ag nanoparticles increases. While, by Cu and Ag ions sequential implantation, uniform Ag nanoparticles with wide distribution are formed. The morphology of Ag nanoparticles changes to hollow and sandwiched nanoparticles by Cu^+ ion irradiation to doses of 3×10^16 and 5×10^16 ions/cm^2. The optical absorption properties of Ag nanoparticles are also tailored by these ways.展开更多
The electrochemical behavior of pirarubicin(THP) and its interaction with DNA at a Co/GC modified electrode was studied by linear sweep and cyclic voltammetries. In a 0.01 mol/L B-R buffer solution(pH=7.0), the reacti...The electrochemical behavior of pirarubicin(THP) and its interaction with DNA at a Co/GC modified electrode was studied by linear sweep and cyclic voltammetries. In a 0.01 mol/L B-R buffer solution(pH=7.0), the reaction of DNA with THP formed an electrochemical nonactive complex, resulting in a decrease in the THP equilibrium concentration and its reduction current. The composition of the complex was THP∶DNA=2∶1. The combining constant is 2.73×10 10 . The electrode reaction rate constant k s and the electron transfer coefficient α are 1.32 s -1 and 0.56, respectively. The decrease in the peak current was proportional to the DNA concentration and was used to determine the DNA concentration. The experiment of XPS showed that Co was surely implanted into the surface of GCE(glassy carbon electrode) and the implanted Co at GCE can improve the electrocatalytic activity.展开更多
Isothermal and cyclic oxidizing behavior of Co-40Cr alloy and its lanthanum ion-implanted samples were studied at 1000 ℃ in the air by thermal-gravimetric analysis (TGA). Scanning electronic microscopy (SEM) and ...Isothermal and cyclic oxidizing behavior of Co-40Cr alloy and its lanthanum ion-implanted samples were studied at 1000 ℃ in the air by thermal-gravimetric analysis (TGA). Scanning electronic microscopy (SEM) and transmission electronic microscopy (TEM) were used to examine the morphology and structure of oxide film after oxidation. Secondary ion mass spectrum (SIMS) method was used to examine the binding energy change of chromium caused by La-doping and its influence on the formation of Cr2O3 film. laser Raman spectrum was used to examine the stress changes within the oxide film. It was found that lanthanum implantation remarkably reduced isothermal oxidizing rate of Co-40Cr and improved anti-cracking and anti-spalling properties of Cr2O3 oxide film. The reasons for the improvement were mainly that the implanted lanthanum reduced the grain size and internal stress of Cr2O3 oxide and increased high temperature plasticity of the oxide film. Lanthanum mainly existed on the outer surface of Cr2O3 oxide film in the form of fine La2O3 and LaCrO3 spinel particles.展开更多
We report the preparation of p-type ZnO thin films on (0001) sapphire substrates by a combination of sol-gel and ion-implantation techniques. The results of the Hall-effect measurements carried out at room temperatu...We report the preparation of p-type ZnO thin films on (0001) sapphire substrates by a combination of sol-gel and ion-implantation techniques. The results of the Hall-effect measurements carried out at room temperature indicate that the N-implanted ZnO:Al films annealed at 600℃ have converted to p-type conduction with a hole concentration of 1.6 × 1018 cm^-3, a hole mobility of 3.67cm^2/V· s and a minimum resistivity of 4.80 cm-Ω. Ion-beam induced damage recovery has been investigated by x-ray diffraction (XRD), photoluminescence (PL) and optical transmittance measurements. Results show that diffraction peaks and PL intensities are decreased by N ion implantation, but they nearly recover after annealing at 600℃. Our results demonstrate a promising approach to fabricate p-type ZnO at a low cost.展开更多
Optical planar waveguides in Yba+-doped phosphate glasses are fabricated by implanting triple-energy helium ions. The guiding modes and the near-field intensity distribution are measured by using the prism-coupling m...Optical planar waveguides in Yba+-doped phosphate glasses are fabricated by implanting triple-energy helium ions. The guiding modes and the near-field intensity distribution are measured by using the prism-coupling method and the end-face coupling setup with a He Ne laser at 633 nm The intensity calculation method (ICM) is used to reconstruct the refractive index profile of the waveguide. The absorption and the fluorescence investigations reveal that the glass bulk features are well preserved in the active volumes of the waveguides, suggesting the fabricated structures for possible applications as waveguide lasers.展开更多
Heavy metals have seriously contaminated soil and water, and done harm to public health. Academician WANG Naiyan proposed that ion-implantation technique should be exploited for environmental bioremediation by mutatin...Heavy metals have seriously contaminated soil and water, and done harm to public health. Academician WANG Naiyan proposed that ion-implantation technique should be exploited for environmental bioremediation by mutating and breeding plants or microbes. By implanting N^+ into Taikonglian No.l, we have selected and bred two lotus cultivars, Jingguang No.1 and Jingguang No.2. The present study aims at analyzing the feasibility that irradiation can be used for remediation of soil and water from heavy metals. Compared with parent Taikonglian No.l, the uptaking and accumulating ability of heavy metals in two mutated cultivars was obviously improved. So ion implantation technique can indeed be used in bioremediation of heavy metals in soil and water, but it is hard to select and breed a cultivar which can remedy the soil and water from all the heavy metals.展开更多
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 4×1...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.展开更多
基金the National Natural Science Foundation of China(No.61904175)Jiangsu Provincial Key Research and Development Program(No.BE2020033)。
文摘Ion implantation induced damage in GaSb and its removal by rapid thermal annealing(RTA)have been investigated by Raman spectroscopy.The evolution of the Raman modes as a function of implantation fluence,annealing temperature and time has been analyzed.Results indicate that a lattice quality that is close to as-grown GaSb has been obtained by annealing the implanted samples at 500℃for 45 s.However,consequent surface analyses by scanning electron microscope(SEM)and atomic force microscope(AFM)show that a heavily perturbed layer contains voids due to the outdifiusion of Sb atoms on the surface remains.Mechanism of the damage recovery and the structure of the implanted layer are discussed based on the experimental results.
文摘The research on plasma immersion ion implantation has been conducted for a little over ten years. Much is needed to investigate including processing technlogy, plasma sheath dynamics, interaction of plasma and surface, etc. Of the processing methods elavated temperature technique is usually used in PIII to produce a thick modified layer by means of the thermal diffusion. Meanwhile plasma ion heating is more recently developed by Ronghua Wei et al[1]. Therefore the temeperature is a critical parameter in plasma ion processing. In this paper we present the theoretical model and analysize the effect of imlantation voltage, plasma density, ion mass,etc on the temperature rise.
文摘The tribological behaviors of TiN coating and TiN+TiC+Ti(C, N)/diamond like carbon (DLC), TiN/DLC, TiC/DLC multilayers on Ti 6Al 4V alloy prepared by plasma based ion implantation (PBII) were compared. Under the test conditions of counterbody AISI 52100, load 1 N and speed 0.05 m/s, the tribological properties of the alloy are improved by these films in the order of TiN, TiC/DLC, TiN/DLC and TiN+TiC+Ti(C,N)/DLC. Tribological behavior is affected by the conditions of surface modification and triboexperiments. The appearance of “peaks” in the wear dynamic resistance profiles may be due or correspond to the process of formation and breaking apart of transition films. The breakthrough of the DLC coated samples may start from partially wearing out, and end with joining piece dilamination. There are transition films on all counterbodies AISI 52100. When AISI 52100 counterbody is changed to Ti 6Al 4V, the wear of most modified samples is changed from only disc to both disc and ball abrasive dominated.
基金the General Program of National Science Foundation of China(No.10375066)
文摘Bacillus megaterium BM302 bred by ion-beam implantation produces L-sorbose dehydrogenase accelerative protein (SAP) to accelerate the activity of L-sorbose dehydrogenase (SDH) of Gluconobacter oxydans in the 2-keto-L-gulonic acid (2KLG) fermentation from L-sorbose by the mixed culture of B. megaterium BM302 and G. oxydans. The SAP purified by three chromatographic steps gave 35-fold purification with a yield of 13% and a specific activity of 5.21 units/mg protein. The molecular weight of the purified SAP was about 58 kDa. The SDH accelerative activity of SAP at pH 7 and 50℃ was the highest. Additionally, it retained 60% activity at a pH range of 6.5 ~ 10 and was stable at 20℃ ~ 60℃. After 0.32-unit SAP was added to the single cultured G. oxydans strains, the SDH activity was apparently accelerated and the 2KLG yield of GO29, GO112, GO and GI13 was enhanced 2.1, 3.3, 3.5 and 2.9 folds respectively over that of the strains without the addition of SAP.
基金the National Key Technologies R & D Program of China during the 10th Five-Year Plan(No.2001BA302B)
文摘As a new mutagenetic method, low-energy ion implantation has been used widely in many research areas in recent years. In order to obtain some industrial strains with high xylanase yield, the wild type strain Aspergillus niger A3 was mutated by means of nitrogen ions implantation (10 keV, 2.6× 10^14 ~ 1.56 × 10^15 ions/cm^2) and a mutant N212 was isolated subsequently. However, it was found that the initial screening means of the high-yielding xylanase strains such as transparent halos was unfit for first screening. Compared with that of the wild type strain, xylanase production of the mutant N212 was increased from 320 IU/ml to 610 IU/ml, and the optimum fermentation temperature was increased from 28 ℃ to 30 ℃.
基金supported by the Knowledge Innovation Project of the Chinese Academy of Sciences (No.KSCX2-SW-324)
文摘In order to generate a mutant of Bacillus subtilis with enhanced surface activity through low energy nitrogen ion beam implantation, the effects of energy and dose of ions implanted were studied. The morphological changes in the bacteria were observed by scanning electron microscope (SEM). The optimum condition of ions implantation, 20 keV of energy and 2.6 × 10^15N^+/cm^2 in dose, was determined. A mutant, B.s-E-8 was obtained, whose surface activity of 50-fold and 100-fold diluted cell-free Landy medium was as 5.6-fold and 17.4-fold as the wild strain. The microbial growth and biosurfactant production of both the mutant and the wild strain were compared. After purified by ultrafiltration and SOURCE 15PHE, the biosurfactant was determined to be a complex of surfactin family through analysis of electrospray ionization mass spectrum (ESI/MS) and there was an interesting finding that after the ion beam implantation the intensities of the components were different from the wild type strain.
基金This work was financially supported by the Scientific Research Common Program of Beijing Municipal Commission of Education (No. KM200510017005).
文摘Magnesium alloys have a wide range of applications in industry; however, their corrosion resistance, wear resistance, and hardness are rather poor, which limit their applications. Ti ion was implanted into the AZ31 magnesium alloy surface by metal vapor vacuum arc (MEVVA) implanter. This metal arc ion source has a broad beam and high current capabilities. The implantation energy was fixed at 45 keV and the dose was at 9×10^17 cm^-2. Through ion implantation, Ti ion implantation layer with approximately 900 um in thickness was directly formed on the surface of AZ31 magnesium alloy, by which its surface property greatly improved. The chemical states of some typical elements of the ion implantation layer were analyzed by means of X-ray photoelectron spectroscopy (XPS), while the cross sectional morphology of the ion implantation layer and the phase structure were observed by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The property of corrosion resistance of the Ti ion implanted layer was studied by the CS300P electrochemistry corrosion workstation in 3.5% NaCl solution. The results showed that the property of corrosion resistance was enhanced remarkably, while the corrosion velocity was obviously slowed down.
文摘With ion implantation (N+, energy 10 keV and dosage 1.56×1015 N+cm-2), a high xylanase-producing strain Aspergillus niger N212 was selected. Based on an orthogonal experiment, an optimal fermentation condition was designed for this high-yield strain. The suitable medium was composed of 8% corncob; 1.0% wheat bran; 0.1%TWEEN20; 0.5% (NH4)2SO4; 0.5%NaNO3; 0.5%FeSO4, 7.5 × 10-4; MnSO4·H2O, 2.5 × 10-4; ZnSO4, 2.0 × 10-4; CoCl2, 3.0 × 10-4. At present, under our experiment condition, xylanase activity of Aspergillus niger N212 reached a level of 600 IU/ml, almost increased by 100% in xylanase production and the time of yielding xylanase was largely reduced to 12 h at 28℃.
文摘This paper reports that ion implantation to a dose of 1 ×10^17 ions/cm^2 was performed on c-axis-orientated ZnO thin films deposited on (0001) sapphire substrates by the sol-gel technique. After ion implantation, the as-implanted ZnO films were annealed in argon ambient at different temperatures from 600 - 900 ℃. The effects of ion implantation and post-implantation annealing on the structural and optical properties of the ZnO films were investigated by x-ray diffraction (XRD), photoluminescence (PL). It was found that the intensities of (002) peak and near band edge (NBE) exitonic ultraviolet emission increased with increasing annealing temperature from 600- 900 ℃. The defect related deep level emission (DLE) firstly increased with increasing annealing temperature from 600 - 750 ℃, and then decreased quickly with increasing annealing temperature. The recovery of the intensities of NBE and DLE occurs at ~850℃ and ~750℃ respectively. The relative PL intensity ratio of NBE to DLE showed that the quality of ZnO films increased continuously with increasing annealing temperature from 600 - 900 ℃.
文摘Plasma-immersion ion implantation (PIII) is a technique for implanting ions into conducting, semiconducting and insulating objects. In PIII, the object being treated is immersed in a plasma and pulsed to a large negative voltage (=-1 to-100 kV). The resulting sheath expands into the ambient plasma, extracting ions and accelerating them to the target. PIII has advantages over beam-line implantation in that large surfaces can be rapidly implanted, irregularly-shaped objects can be implanted without target manipulation, and surfaces that are not line-of-sight accessible can be treated. A two-dimensional, self-consistent model of plasma dynamics appropriate for PIII is described. The model is a hybrid, with Boltzmann electrons and kinetic ions, where the ion Vlasov equation is solved using the particle-in-cell (PIC) method. Solutions of the model give the time dependence of the ion flux, energy and impact angle at the target surface, together with the evolution of the sheath.
基金supported by National Key Project of China (No. 2001BA302B)
文摘Low-energy ion implantation, as a new technology to produce mutation in plant breeding, has been widely applied in agriculture in China. But so far there is a little understanding of the underlying mechanisms responsible for its biological effects at the cellular level. Here we report the biological effects of a nitrogen ion beams of 30 keV on the pollen grains of Pinus thunbergii Parl. In general, ion implantation inhibited pollen germination. The dose-response curve presented a particular saddle-like pattern. Ion implantation also changed the dimension of the elongated tubes and significantly induced tip swelling. Confocal microscopy indicated that the pollen tube tips in P. thunbergii contained an enriched network of microtubules. Ion implantation led to the disruption of microtubules especially in swollen tips. Treatment with colchicine demonstrated that tip swelling was caused by the disruption of microtubules in the tip, indicating a unique role for microtubules in maintaining the tip integrality of the pollen tube in conifer. Our results suggest that ion implantation induce the disruption of microtubule organization in pollen and pollen tubes and subsequently cause morphological abnormalities in the pollen tubes. This study may provide a clue for further investigation on the interaction between low-energy ion beams and pollen tube growth.
文摘Plasma immersion ion implantation (PIII), unrestricted by sight-light process, is considered a proper method for inner surface strengthening. Two-dimensional simulation oj inner surface PIII process of cylindrical bores were carried out in this paper using cold plasma fluid model, and influence of the bore's dimension on impact energy, retained dose and uniformity of inner surface were investigated.
文摘The surface properties of Ti-6Al-4V alloy coated with titanium nitride, TiN+TiC+Ti(C,N)/DLC (diamond like carbon), TiN/DLC and TiC/DLC films by plasma-based ion implantation (PBII) with nitrogen, PBII with nitrogen then acetylene, PBII with nitrogen then glow discharge deposition with acetylene plus hydrogen and PBII with acetylene then glow discharge deposition with acetylene plus hydrogen respectively were studied. The corresponding films are found getting dimmer, showing light gold or gold, smoky color (uneven), light red in black (uneven), and graphite black separately. The corresponding film resistivities are given. Antioxidation ability of the titanium nitride film is poor, while the existence of carbon (or carbide) improves the antioxidation ability of the films. Having undergone excellent intermediate transitional region of nitrogen and carbon implantation, the top DLC layer of the TiN+TiC+Ti(C,N)/DLC multilayer are formed after the carbon implantation has the best adhesion with the substrate among all the multilayers. Although microhardness of the samples increases in the order of coatings of titanium nitride, TiN/DLC, TiN+TiC+Ti(C,N)/DLC and TiC/DLC, the TiN/DLC and TiC/DLC multilayers have greater brittleness as compared with other films.
基金supported by the National Natural Science Foundation of China(No.10435060 and 10775109)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20050486054 and 20070486069)the Young Chenguang Project of Wuhan City(No.200850731371)
文摘Ion implantation is a powerful method for fabricating nanoparticles in dielectric. For the actual application of nanoparticle composites, a careful control of nanoparticles has to be achieved. In this letter, the size, distribution and morphology of Ag nanoparticles are controlled by controlling the ion current density, ion implantation sequence and ion irradiation dose. Single layer Ag nanoparticles are formed by Ag^+ ion implantation at current density of 2.5 μ^A/cm2. By Ag and Cu ions sequential implantation, the size of single layer Ag nanoparticles increases. While, by Cu and Ag ions sequential implantation, uniform Ag nanoparticles with wide distribution are formed. The morphology of Ag nanoparticles changes to hollow and sandwiched nanoparticles by Cu^+ ion irradiation to doses of 3×10^16 and 5×10^16 ions/cm^2. The optical absorption properties of Ag nanoparticles are also tailored by these ways.
基金the National Natural Science Foundation of China(No.2 0 2 75 0 0 7)
文摘The electrochemical behavior of pirarubicin(THP) and its interaction with DNA at a Co/GC modified electrode was studied by linear sweep and cyclic voltammetries. In a 0.01 mol/L B-R buffer solution(pH=7.0), the reaction of DNA with THP formed an electrochemical nonactive complex, resulting in a decrease in the THP equilibrium concentration and its reduction current. The composition of the complex was THP∶DNA=2∶1. The combining constant is 2.73×10 10 . The electrode reaction rate constant k s and the electron transfer coefficient α are 1.32 s -1 and 0.56, respectively. The decrease in the peak current was proportional to the DNA concentration and was used to determine the DNA concentration. The experiment of XPS showed that Co was surely implanted into the surface of GCE(glassy carbon electrode) and the implanted Co at GCE can improve the electrocatalytic activity.
基金the National Natural Science Foundation of China (29231011)the Natural Science Foundation of Jiangsu Province (07KJD430246)
文摘Isothermal and cyclic oxidizing behavior of Co-40Cr alloy and its lanthanum ion-implanted samples were studied at 1000 ℃ in the air by thermal-gravimetric analysis (TGA). Scanning electronic microscopy (SEM) and transmission electronic microscopy (TEM) were used to examine the morphology and structure of oxide film after oxidation. Secondary ion mass spectrum (SIMS) method was used to examine the binding energy change of chromium caused by La-doping and its influence on the formation of Cr2O3 film. laser Raman spectrum was used to examine the stress changes within the oxide film. It was found that lanthanum implantation remarkably reduced isothermal oxidizing rate of Co-40Cr and improved anti-cracking and anti-spalling properties of Cr2O3 oxide film. The reasons for the improvement were mainly that the implanted lanthanum reduced the grain size and internal stress of Cr2O3 oxide and increased high temperature plasticity of the oxide film. Lanthanum mainly existed on the outer surface of Cr2O3 oxide film in the form of fine La2O3 and LaCrO3 spinel particles.
基金Project supported by the Program for New Century Excellent Talents in University (Grant No NCET-04-0899)Special Foundation for University Subject Construction, Department of Education of Guangdong Province, China (Grant No [2006] 11)
文摘We report the preparation of p-type ZnO thin films on (0001) sapphire substrates by a combination of sol-gel and ion-implantation techniques. The results of the Hall-effect measurements carried out at room temperature indicate that the N-implanted ZnO:Al films annealed at 600℃ have converted to p-type conduction with a hole concentration of 1.6 × 1018 cm^-3, a hole mobility of 3.67cm^2/V· s and a minimum resistivity of 4.80 cm-Ω. Ion-beam induced damage recovery has been investigated by x-ray diffraction (XRD), photoluminescence (PL) and optical transmittance measurements. Results show that diffraction peaks and PL intensities are decreased by N ion implantation, but they nearly recover after annealing at 600℃. Our results demonstrate a promising approach to fabricate p-type ZnO at a low cost.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 61077070, 10876009, and 51002181)the One Hundred Talents Programs of the Chinese Academy of Sciences
文摘Optical planar waveguides in Yba+-doped phosphate glasses are fabricated by implanting triple-energy helium ions. The guiding modes and the near-field intensity distribution are measured by using the prism-coupling method and the end-face coupling setup with a He Ne laser at 633 nm The intensity calculation method (ICM) is used to reconstruct the refractive index profile of the waveguide. The absorption and the fluorescence investigations reveal that the glass bulk features are well preserved in the active volumes of the waveguides, suggesting the fabricated structures for possible applications as waveguide lasers.
基金supported by National Natural Science Foundation of China (No.11075019)Beijing Ion-Irradiating-Breeding Research Platform Project of China
文摘Heavy metals have seriously contaminated soil and water, and done harm to public health. Academician WANG Naiyan proposed that ion-implantation technique should be exploited for environmental bioremediation by mutating and breeding plants or microbes. By implanting N^+ into Taikonglian No.l, we have selected and bred two lotus cultivars, Jingguang No.1 and Jingguang No.2. The present study aims at analyzing the feasibility that irradiation can be used for remediation of soil and water from heavy metals. Compared with parent Taikonglian No.l, the uptaking and accumulating ability of heavy metals in two mutated cultivars was obviously improved. So ion implantation technique can indeed be used in bioremediation of heavy metals in soil and water, but it is hard to select and breed a cultivar which can remedy the soil and water from all the heavy metals.
文摘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.