自悬浮定向流法制备Ti纳米颗粒及结构表征

采用自悬浮定向流法制备钛纳米颗粒,并使用透射电镜、X射线衍射和X射线光电子能谱等方法,对钛纳米颗粒的形貌、粒度、结构及性能进行研究。结果表明：钛纳米颗粒呈球形,随着冷却气体Ar流速的增加,平均粒径逐渐减小,在流速为0.6、0.8和1.0 m³/h条件下,分别得到平均粒径为59、50和41 nm的钛纳米颗粒;在空气中,钛纳米颗粒极易氧化生成二氧化钛,同时能够与空气中的N₂和水蒸气发生反应,生成少量的氮化物及羟基基团。     

Spectroscopic studies of fuel recycling and impurity behaviors in the divertor region of Wendelstein 7-X

The first divertor operation phase(OP1.2 a) was carried out on Wendelstein 7-X in the second half of 2017.Fuel recycling and impurity behaviors in the divertor region were investigated by employing a newly built ultraviolet–visible–near infrared overview spectroscopy system.The characteristic spectral lines of the working gases(hydrogen and helium),intrinsic impurities(carbon,oxygen and iron),and seeded impurities(neon and nitrogen) were identified and analyzed.The divertor electron temperature and density were measured using He I(667.8,706.5,and 728.1 nm) line intensity ratios.The Hα(656.3 nm),He I(587.6 nm),C II(514.5 nm),and O I(777.2 nm) emissions were investigated over a wide range of operating conditions.The results showed that fuel and impurity emissions in the divertor region exhibit a strong dependence on magnetic topology and plasma conditions.The levels of Hα,He I,C II,and O I emissions are all reduced moving from the standard configuration to the high mirror configuration,and even further reduced for the high iota configuration,which is associated with decreasing connection length in these island divertor configurations.The H/He influx ratio shows that the plasma is a mixture of helium and hydrogen.The neutral and impurity influxes from the divertor target tend to increase with increasing divertor electron temperature.     

同步辐射圆二色谱法研究Fe3O4纳米颗粒对细胞色素C结构的影响

四氧化三铁纳米颗粒(Fe3O4-NPs)在生物医学领域有着广泛的应用。通过同步辐射真空紫外圆二色谱(SRCD)和紫外可见(UV-Vis)吸收谱技术研究了Fe3O4纳米颗粒的粒径(10 nm和40 nm)对细胞色素C(Cyt c)结构的影响。结果表明,随着Fe3O4-NPs颗粒物浓度的增大,Cyt c在408 nm处的吸光度值逐渐下降。SRCD结果显示Cyt c与Fe3O4-NPs作用后,蛋白的α螺旋含量减少,β折叠含量增加;Fe3O4-NPs与Cyt C的作用强度具有尺寸依赖性,小尺寸的Fe3O4-NPs作用更为明显。     

Plasma nitridation of thin SiO2 films: AES, ELS and IR study

Auger electron spectroscopy, low-energy electron loss spectroscopy and infrared spectroscopy are used to investigate the nitridation of thin (10–22 nm) thermal SiO₂ in RF soft NH₃ plasma. It is found that plasma action at a substrate temperature of 573 K can completely nitridate the thermal oxide to an oxynitride layer. The layers obtained are macroscopic mixtures of two phases SiO₂ and Si₃N₄, rather than amorphous polymers of Si, O and N.     

Synthesis of nanostructured multiphase Ti(C,N)/a-C films by a plasma focus device

Nanostructured multiphase Ti(C,N)/a-C films were deposited using a 3.3 kJ pulsed plasma focus device onto silicon (1 0 0) substrates at room temperature. The plasma focus device, fitted with solid titanium anode instead of usual hollow copper anode, was operated with nitrogen and Ar/CH₄ as the filling gas. Films were deposited with different number of shots, at 80 mm from top of the anode and at zero angular position with respect to anode axis. X-ray diffraction results show the diffraction peaks related to different compounds such as TiC₂, TiN, Ti₂CN, Ti and TiC_0.62 confirming the deposition of multiphase titanium carbo-nitride composite films on silicon. X-ray photoelectron spectroscopy confirms the formation of Ti–C, C–N, Ti–N, Ti–O and C–C bonds in the films. Scanning electron microscopy reveals that the nanostructure grains are agglomerates of smaller nanoparticles about 10–20 nm in size. Raman studies verify the formation of multiphase Ti(C,N) and also of amorphous graphite in the films. The maximum microhardness value of the composite film is 14.8 ± 1.3 GPa for 30 shots.     

Reactive DC Magnetron Sputter Deposited Titanium-Copper-Nitrogen Nano-Composite Thin Films with an Argon/Nitrogen Gas Mixture

A sintered Ti13Cu87 target was sputtered by reactive direct current (DC) magnetron sputtering with a gas mixture of argon/nitrogen for different sputtering powers. Titanium-copper-nitrogen thin films were deposited on Si (111), glass slide and potassium bromide (KBr) substrates. Phase analysis and structural properties of titanium-copper-nitrogen thin films were studied by X-ray diffraction (XRD). The chemical bonding was characterized by Fourier transform infrared (FTIR) spectroscopy. The results from XRD show that the observed phases are nano-crystallite cubic anti rhenium oxide (anti ReO3) structures of titanium doped Cu3N (Ti:Cu3N) and nano-crystallite face centered cubic (fcc) structures of copper. Scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM/EDX) were used to determine the film morphology and atomic titanium/copper ratio, respectively. The films possess continuous and agglomerated structure with an atomic titanium/copper ratio ( 0.07) below that of the original target ( 0.15). The transmittance spectra of the composite films were measured in the range of 360 to 1100 nm. Film thickness, refractive index and extinction coefficient were extracted from the measured transmittance using a reverse engineering method. In the visible range, the higher absorption coefficient of the films prepared at lower sputtering power indicates more nitrification in comparison to those prepared at higher sputtering power. This is consistent with the formation of larger Ti:Cu3N crystallites at lower sputtering power. The deposition rate vs. sputtering power shows an abrupt transition from metallic mode to poisoned mode. A complicated behavior of the films’ resistivity upon sputtering power is shown.     

N-TiO2 nanoparticles embedded in silica prepared by Ti ion implantation and annealing in nitrogen

Room-temperature Ti ion implantation and subsequent thermal annealing in N₂ ambience have been used to fabricate the anatase and rutile structured N-doped TiO₂ particles embedded in the surface region of fused silica. The Stopping and Range of Ions in Matter (SRIM) code simulation indicates a Gaussian distribution of implanted Ti, peaked at ∼75 nm with a full width at half maximum of ∼80 nm. However, the transmission electron microscopy image shows a much shallower distribution to depth of ∼70 nm. Significant sputtering loss of silica substrates has occurred during implantation. Nanoparticles with size of 10-20 nm in diameter have formed after implantation. X-ray photoelectron spectroscopy indicates the coexistence of TiO₂ and metallic Ti in the as-implanted samples. Metallic Ti is oxidized to anatase TiO₂ after annealing at 600 °C, while rutile TiO₂ forms by phase transformation after annealing at 900 °C. At the same time, N-Ti-O, Ti-O-N and/or Ti-N-O linkages have formed in the lattice of TiO₂. A red shift of 0.34 eV in the absorption edge is obtained for N-doped anatase TiO₂ after annealing at 600 °C for 6 h. The absorbance increases in the ultraviolet and visible waveband.     

RBS study of Ti/ZnO interface

We have studied the interface stability of the Ti(overlayer)/ZnO(substrate) system. Ti thin film was grown on the Zn face of single crystal ZnO(0 0 0 1) substrate by the vacuum deposition technique. The Ti film thickness was typically 16 nm. Then the samples were annealed in air at 300 and 400 °C for 15 min, respectively. The deposition and annealing effects on the interface structure were investigated with Rutherford backscattering and channeling spectroscopy using 2 MeV He⁺ ion beam. After Ti deposition the minimum yield from the ZnO substrate increased from 2% to 7%. This suggests severe damage caused by deposition, i.e. the interface reaction between Ti and ZnO (even at room temperature). A significant amount of Zn (approximately 6.4 × 10¹⁶ atoms/cm²) moved onto the surface after post-annealing at 400 °C. Since Ti has a stronger tendency to react with O than Zn, it is expected that Ti reacts with substrate oxygen leaving behind free Zn atoms, which can easily migrate onto the surface. We discuss how the Ti/ZnO interface reaction in detail, and seek to find another good metallic contact for ZnO devices, which are attracting much attention recently for practical applications as well as scientific aspects.     

Spectral characteristic of laser-induced plasma in soil

The spectral characteristic of laser-induced plasma in soil was studied in this work, laser-induced breakdown spectroscopy was used to analyze the spectral characteristic of plasma under the condition of different time delays and irradiances. Moreover, the time evolution characteristics of plasma temperature and electron density were discussed. Within the time delay range of 0-5 μs,the spectral intensity of the characteristic lines of Si I: 288.158 nm, Ti I: 336.126 nm, Al I:394.400 nm and Fe I: 438.354 nm of the four main elements in two kinds of national standard soil decayed exponentially with time. The average lifetime of the spectral lines was nearly 1.56 μs. Under the condition of different time delays, the spectral intensity of Pb I: 405.78 nm in soil increased linearly with laser energy. However, the slope between the spectral intensity and laser energy decreased exponentially with the increase in time delay, from 4.91 to 0.99 during 0-5 μs. The plasma temperature was calculated by the Boltzmann plot method and the electron density was obtained by inversion of the full width at half maximum of the spectrum. The plasma temperature decreased from 8900 K to 7800 K and the electron density decreased from 1.5 × 10~(17) cm~(-3) to 7.8 × 10~(16) cm~(-3) in the range of 0-5 μs.     

Fe_3O_4/聚丙烯酸/CdS复合粒子的光化学制备及光催化性能

采用光引发丙烯酸聚合的方法对Fe3O4纳米粒子进行表面改性,制备了羧基功能化的Fe3O4/聚丙烯酸复合纳米粒子(Fe3O4/PAA);以Fe3O4/PAA为磁核,以硫酸镉和硫代硫酸钠为原料,采用光化学方法制备Fe3O4/聚丙烯酸/CdS复合粒子(Fe3O4/PAA/CdS),并借助红外光谱、X射线粉末衍射、透射电子显微镜、荧光光谱和振动样品磁强计对其进行表征。结果表明,核-壳结构的Fe3O4/PAA/CdS为表面粗糙的球形粒子,平均粒径为155 nm,具有发光性能和准超顺磁性。Fe3O4/PAA/CdS在有机染料罗丹明B的降解实验中显示出良好的可见光催化活性,可以借助磁铁在2 min内从溶液中完全回收。     

High fluence nitrogen implantation in Al/Ti multilayers

We have studied the effects of high fluence nitrogen ion implantation on the structural changes in Al/Ti multilayers, with the aim of achieving multilayered metal-nitrides. The starting structures consisted of 10 alternate sputter-deposited Al and Ti films, with a total thickness of 270 nm, on (1 0 0) Si substrates. They were implanted with 200 keV , to 1 × 10¹⁷ and 2 × 10¹⁷ at/cm², the projected range being around half-depth of the multilayers. Structural characterization was performed by Rutherford backscattering, Auger electron spectroscopy and transmission electron microscopy. It was found that ion implantation to the higher fluence induces a full intermixing of Al/Ti layers, resulting in a multilayered structure with different content of Al, Ti and N. The applied method can be interesting for preparation of graded (Al,Ti)N multilayers, with a controlled content of nitrogen and a controlled level of Al-Ti intermixing within the structures.     

Microstructure and oxidation properties of 16Cr–5Al–ODS steel prepared by sol–gel and spark plasma sintering methods

The 16Cr–5Al oxide dispersion strengthened (ODS) ferritic steel was fabricated by sol–gel method in combination with hydrogen reduction, mechanical alloying (MA) and spark plasma sintering (SPS) techniques. The phase characterization, microstructure and oxidation resistance of the 16Cr–5Al–ODS steel were investigated in comparison with the Al free 16Cr–ODS steel. X-ray diffraction (XRD) patterns showed that the Al free and Al added 16Cr–ODS steels exhibited typical ferritic characteristic structure. The microstructure analysis investigated by transmission electron microscopy (TEM) and energy dispersive spectrometry (EDS) revealed that Y–Ti–O complexes with particle size of 10–30 nm were formed in the Al free matrix and Y–Al–O complexes with particle size of 20–100 nm were formed in the Al contained high-Cr ODS steel matrix. These complexes are homogeneously distributed in the matrices. The fabricated 16Cr–5Al–ODS steel exhibited superior oxidation resistance compared with the Al free 16Cr–ODS steel and the commercial 304 stainless steel owing to the formation of continuous and dense Al₂O₃ film on the surface.     

Efficient removal of Co(Ⅱ) from aqueous solution by titanate sodium nanotubes

In this paper,a novel material for Co(Ⅱ)adsorption,titanate sodium nanotubes(Na_2Ti_2O_5-NTs)were synthesized and characterized,and then they were used to remove Co(Ⅱ) from aqueous solution and compared with titanic acid nanotubes(H_2Ti_2O_5-NTs) and potassium hexatitanate whiskers(K_2Ti_6O_(13)).The results showed that the adsorption of Co(Ⅱ) on the materials was dependent on p H values and was a spontaneous,endothermic process.Specifically,Na_2Ti_2O_5-NTs exhibited much more efficient ability to adsorb Co(Ⅱ) from aqueous solution,with the maximum adsorption capacity of 85.25 mg/g.Furthermore,Na_2Ti_2O_5-NTs could selectively adsorb Co(Ⅱ) from aqueous solution containing coexisting ions(Na~+,K~+,Mg~(2+),and Ca~(2+)).The results suggested that Na_2Ti_2O_5-NTs were potential effective adsorbents for removal of Co(Ⅱ) or cobalt-60 from wastewater.     

Rapid Detection of Oil Pollution in Soil by Using Laser-Induced Breakdown Spectroscopy

Detection of oil pollution in soil has been carried out using laser-induced breakdown spectroscopy(LIBS). A pulsed neodymium-doped yttrium aluminum garnet(Nd:YAG) laser(1,064 nm, 8 ns, 200 mJ) was focused onto pelletized soil samples. Emission spectra were obtained from oil-contaminated soil and clean soil. The contaminated soil had almost the same spectrum profile as the clean soil and contained the same major and minor elements. However, a C–H molecular band was clearly detected in the oil-contaminated soil, while no C–H band was detected in the clean soil. Linear calibration curve of the C–H molecular band was successfully made by using a soil sample containing various concentrations of oil. The limit of detection of the C–H band in the soil sample was 0.001 mL/g. Furthermore, the emission spectrum of the contaminated soil clearly displayed titanium(Ti) lines, which were not detected in the clean soil. The existence of the C–H band and Ti lines in oil-contaminated soil can be used to clearly distinguish contaminated soil from clean soil. For comparison, the emission spectra of contaminated and clean soil were also obtained using scanning electron microscope-energy dispersive X-ray(SEM/EDX) spectroscopy,showing that the spectra obtained using LIBS are much better than using SEM/EDX, as indicated by the signal to noise ratio(S/N ratio).     

Microstructure and mechanical properties of Fe alloys ion implanted with Ti and N

The microstructure resulting when Ti and N are both ion-implanted into pure Fe at room temperature has been examined with ion beam analysis, transmission electron microscopy, and electron energy loss spectroscopy. Precipitates of TiN form within the bcc Fe matrix, in contrast to the amorphous phase which forms when Ti and C are both implanted. For comparison, the microstructure resulting when N alone is implanted into Fe was also examined, and Fe₂N precipitates were observed within the Fe matrix. The surface mechanical properties of 15?5 PH steel which was implanted with both Ti and N were examined with pin-on-disc testing, and the results were interpreted in terms of the microstructures observed in Fe. The modifications produced by Ti + N implantation are the same as observed with other treatments producing hard nitrides or carbides within the iron-based matrix: reduced wear is observed, but not reduced friction.     

钛膜中氘氚浓度的弹性反冲法测量

研究采用弹性反冲探测(ERD)方法测量钛膜中氘、氚的浓度。实验所用Ti膜用磁控溅射法制备，膜厚小于100nm，以石英玻璃（SiO₂）为底衬，Ti膜加镀了1层Ni保护膜，以防Ti膜氧化和增强Ti膜吸氢。以6.0MeVO粒子作为入射粒子，在30°方向上探测反冲粒子，在此实验条件下，O粒子对D、T的碰撞截面为卢瑟福截面。对两个样品用ERD方法测量钛膜中的D、T含量，获得了D、T的面密度。测量结果表明，采用如上方法测量Ti膜中D、T浓度的误差小于7％。     

贮氢金属多层膜制备技术及吸氢性能研究

研究了用电子束蒸发方法在Mo底衬上制备Ti-Ni复合膜和在SiO2底衬上制备Mo-Ti-Ni复合膜的方法,用离子束分析方法测量了各膜层的厚度,并对样品的吸氢性能进行了分析。研究发现,Ti膜表面镀Ni后,其吸氢温度降低,吸氢总量增加,表明其吸氢活性增强;Mo-Ti-Ni复合膜在Ti氢化后与SiO2底衬结合良好,并具有较高的强度,但这种膜对底衬的清洁度要求更高;50nm的Ti膜难以吸氢,原因可能是膜制备过程中温度过高,导致Mo-Ti-Ni之间扩散加深,形成相对过厚的过渡层,这还需进一步研究。     

冠醚包覆聚苯乙烯磁性颗粒的合成、表征及其对锶离子的吸附性能

为建立应用磁性颗粒快速分离低水平~(90)Sr的方法,分别以沉淀法合成Fe_3O_4纳米颗粒,微乳聚合法合成磁性聚苯乙烯-二乙烯苯颗粒(Pst-DVB@Fe_3O_4),并将4,4’(5’)-二叔丁基二环己基-18-冠-6(DtBuCH18C6)通过物理作用包覆在Pst-DVB@Fe_3O_4颗粒表面,最终生成一种新型的核-壳结构的DtBuCH18C6包覆的聚合物磁性颗粒(DtBuCH18C6@Pst-DVB@Fe_3O_4)。采用扫描电镜、红外光谱、X射线光电子能谱等方法对颗粒的形貌、结构、表面元素组成及含量进行分析。用于分离水溶液中Sr~(2+)的批实验结果表明,Sr~(2+)的吸附量随着pH值而增加,而在pH=11和pH=13之间急剧上升,温度升高,其吸附量增加。吸附动力学模型结果表明,Sr~(2+)在DtBuCH18C6@Pst-DVB@Fe_3O_4表面的吸附更接近于其和Sr~(2+)之间形成络合物的单层化学吸附过程,符合Langmuir模型。在优化的条件下其最大吸附容量为2.62 mg/g。     

磁控溅射制备金属铀膜

研究了通过磁控溅射方法制备高纯金属铀膜的可行性。采用X射线衍射（XRD）、俄歇电子能谱（AES）、扫描电镜（SEM）、表面轮廓仪分析了沉积在单晶硅或金基材上铀薄膜的微观结构、成分、界面结构及厚度、表面形貌和表面粗糙度。分析结果表明：磁控溅射制备的铀薄膜为纯金属态,氧含量和其它杂质含量均低于俄歇电子能谱仪的探测下限;溅射沉积的铀镀层与铝镀层之间存在界面作用,两者相互扩散并形成合金相,扩散层厚度约为10nm。铀薄膜厚度可达微米级,表面光洁,均方根（RMS）粗糙度优于15nm。     

Fabrication and characterization of fine-grained 316L steel with 2.0 mass% TiC

Development of fine grain 316L with small amount of TiC for high radiation-tolerant performance was tried considering the fabrication process of thermo-mechanical treatments. The materials obtained are UFG316L+2.0 mass% TiC with the grain size of 90–270 nm, depending on the final annealing temperature from 700 ℃ to 900 ℃. The materials were examined by transmission electron microscopy observation, X-ray absorption near-edge structure spectroscopy, high voltage electron microscope electron irradiation and stress corrosion cracking by crevice bent beam method in high-temperature water with 8 ppm dissolved oxygen. The test results showed that the material is generally of excellent quality. Especially void swelling induced by the electron irradiation at 400 ℃ is less than 1/10 compared to the commercial SUS316L.