Energy-dispersive X-ray Spectroscopy for the Quantitative Analysis of Pyrite Thin Specimens

To explore ways to improve the accuracy of quantitative analysis of samples in the micrometer to nanometer range of magnitudes,we adopted analytical transmission electron microscopy(AEM/EDS)for qualitative and quantitative analysis of pyrite materials.Additionally,the k factor of pyrite is calculated experimentally.To develop an appropriate non-standard quantitative analysis model for pyrite materials,the experimentally calculated k factor is compared with that estimated from the non-standard quantitative analytical model of the instrument software.The experimental findings demonstrate that the EDS attached to a TEM can be employed for precise quantitative analysis of micro-and nanoscale regions of pyrite materials.Furthermore,it serves as a reference for improving the results of the EDS quantitative analysis of other sulfides.

Synthesis, characterization and biocompatibility studies of zinc oxide(ZnO) nanorods for biomedical application

Nanoparticles are increasingly being recognized for their potential utility in biological applications including nanomedicine.Here,we have synthesized zinc oxide(ZnO)nanorods using zinc acetate and hexamethylenetetramine as precursors followed by characterizing using X-ray diffraction,fourier transform infrared spectroscopy,scanning electron microscopy and transmission electron microscopy.The growth of synthesized zinc oxide nanorods was found to be very close to its hexagonal nature,which is confirmed by X-ray diffraction.The nanorod was grown perpendicular to the long-axis and grew along the[001]direction,which is the nature of ZnO growth.The morphology of synthesized ZnO nanorods from the individual crystalline nucleus was confirmed by scanning and transmission electron microscopy.The length of the nanorod was estimated to be around 21 nm in diameter and 50 nm in length.Our toxicology studies showed that synthesized ZnO nanorods exposure on hela cells has no significant induction of oxidative stress or cell death even in higher concentration(10μg/ml).The results suggest that ZnO nanorods might be a safer nanomaterial for biological applications.

Calibration of Binding Energy Positions with C1s for XPS Results

The adventitious carbon located at 284.8 eV was used to calibrate samples without the carbon themselves.When the carbon is as a major part of the inorganic material,the adventitious carbon should be identified and used as the reference.There is no adventitious carbon on the surfaces of the polymer materials,so using C1s of the carbon in the polymer itself to calibrate the charging effect is reasonable.Furthermore,compared with gold and argon,a more practical and convenient method based on C1s is proposed to get the right positions for binding energy peaks.

3D Interconnected MoO_2 Nanocrystals on Nickel Foam as Binder-free Anode for Li-ion Batteries

MoO_2 nanocrystals(NCs) on Ni foam were simply synthesized via a facile hydrothermal method and a dip-coating method. It was worth noting that ultrafine interconnected MoO_2 nanocrystals(about 10 nm) were uniformly anchored on Ni foam to fabricate a particular three-dimensional architecture, which may provide more active sites and shorter transmission pathways for lithium ions. As binder-free anode, MoO_2 NCs on Ni foam deliver a high initial discharge capacity of 990 mAh·g^(-1) and retain a reversible capacity of 924 mAh· g(-1) after 100 cycles at a current density of 0.1 C. More importantly, when the current density returns from 2 C to 0.1 C, the capacity recovers to 910 mAh·g(-1)(about 92% of the original high capacity), suggesting excellent cycling stability and rate capability. The particular 3 D electrode as binder-free anode makes it a promising anode candidate for high-performance lithium-ion batteries.

Enhanced Thermoelectric Performance of Non-equilibrium Synthesized Fe0.4Co3.6Sb12-xGex Skutterudites via Randomly Distributed Multi-scaled Impurity Dots

The p-type Ge doped Fe_(0.4)Co_(3.6)Sb_(12-x)Ge_x skutterudites with multi-scaled impurity dots(500 nm-2 mm) were successfully prepared by using melt-quenching(MQ) and subsequent spark plasma sintering(SPS) technique. Compared with traditional method, the new technology significantly shortened the processing time from several days to less than 24 hours. The phase of impurity dots was demonstrated to be CoSb through analysis of X-ray diffraction(XRD) and energy-dispersive spectrum(EDS). Impurity dots were induced by Ge substitution of Sb in the non-equilibrium synthesized process. Due to the abandonment of the long reaction of annealing crystallization, a few of Ge atoms would fail to substitute Sb site of skutterudite in this non-equilibrium synthesized process, leading to that the multi-scaled impurity dots randomly distributed in the matrix of skutterudite Fe_(0.4)Co_(3.6)Sb_(12-x)Ge_x. The combination of multi-scaled impurity dots scattering long wavelength heat-carrying phonons and the point defect scattering short and middle wavelength heat-carrying phonons dramatically made the 22.2% reduction of lattice thermal conductivity. As a result, compared with unsubstituted sample of Fe_(0.4)Co_(3.6)Sb_(12), the maximum ZT value was increased by 30.5%. Thus, the two marked features of this new synthesis process, the shortened preparation time and the enhanced thermoelectric performance, would make a promising commercial application in the future.

不同熔化条件对Na_2O·4TeO_2玻璃性能的影响

探索了不同熔化条件对 Na2 O· 4Te O2 玻璃性能的影响 ,确定了 Na2 O- Te O2 系统玻璃的合理的熔化条件。通过热分析和红外分析等手段 ,对由不同原料在不同熔化条件下所得到的玻璃进行了分析 ,发现熔化条件不同时 ,由不同原料所得玻璃的性能也有很大差别。当熔化温度较低、熔化时间较短时 ,玻璃中存在未分解完全的来自原料的原子基团。由不同原料所得的玻璃的 DSC曲线和抗析晶能力差别很大。随着熔化温度的升高和熔化时间的延长 ,由不同原料熔化所得玻璃的性能趋于一致。在 80 0℃下熔化 1

PbO-B_2O_3玻璃在不同重力条件下相组成和成分均匀性的研究

以3.5PbO.96.5B2O3(m o l%)玻璃作为研究对象,着重研究其在不同重力条件下的分相现象。该部分讨论了2个落塔实验试样发生分相的重力条件,同时分析了试样的相组成和试样成分的不均匀性。结果发现,该成分玻璃发生分相后形成的富硼相和富铅相都是玻璃相。分相在高重力阶段发生的试样其成分均匀性最差,原因在于富硼相和富铅相间存在较大的密度差。

用差热分析测定玻璃析晶过程的核化速率曲线

本方法通过对玻璃试样 DTA 数据的处理,改进了玻璃晶化过程中成核速率随温度变化曲线的测定方法。此法比用光学显微镜,对试样中可见晶粒进行计数的传统方法,更快速而简便。本实验确认,Li_2O·2SiO_2玻璃的成核速率曲线(I-T)和晶体生长速度曲线(U-T)不重叠。该系统的 DTA 曲线中,晶体放热峰的高度δT可看成是试样中晶核数量的大小。实验还证明,在确定成核温度范围和成核速率达最大值的最佳温度方面,峰高δT随温度变化的曲线可以代替成核速率 I 随温度变化的曲线。由固体相变理论推出的结论,证明了本实验方法的可行性。

Na_2O-TeO_2系统玻璃形成液体脆性的研究

通过测量Na2 O -TeO2 系统玻璃转化区的热容曲线 ,对该系统不同成分玻璃形成液体的热力学和动力学脆性进行研究。结果表明 :该系统玻璃形成液体从热力学和动力学综合看脆性程度介于强弱之间 ,为中性偏脆性。随着氧化钠含量的升高 ,玻璃形成液体的脆性增强。用Kissinger方程和Ritland -Bartanev方程 ,得到的在玻璃转变区的结构松弛激活能十分接近。

不同重力环境下硼铅玻璃的二次分相现象研究

以不同落塔实验所得的硼铅玻璃试样为研究对象,通过微观形貌观察和相分析等手段,研究了硼铅玻璃的二次分相现象。结果发现,所有试样在一次分相形成富硼相和富铅相后,富硼相和富铅相都继续发生了分相,即二次分相现象。不同试样发生二次分相后的微观形貌有很大不同,这主要是由于所发生的二次分相没有遵循现有相图中的不混溶区,而是按照另外一种不混溶区进行的。在PbO-B_2O_3系统中除了已知的不混溶区以外,至少还存在有另外两个不混溶区,这两个不混溶区目前还不能准确定位,本文对这两个不混溶区在相图中的位置进行了大概的估计,而且发现不同重力条件下这些不混溶区在相同中的位置也有很大不同。

不同重力条件对PbO-B_2O_3玻璃分相的影响

研究了PbO—B2O3在不同重力条件下的分相现象,并分析了不同实验条件下试样的成分均匀性以及试样不同部位的显微结构．结果发现,玻璃发生分相后形成连续的富硼相和分散的富铅相．对于分相在高重力阶段发生的试样,顶部富铅相的尺寸远远小于试样的底部,试样顶部的含铅量远远低于试样的底部,因此该试样的成分均匀性最差,其次是在正常重力下发生分相的试样．

Na_2O·8TeO_2晶相的转变分解机理探索

以Na_2O-TeO_2玻璃系统中发现的一个新晶相Na_2O·8TeO_2(NT_8)为研究对象,通过热分析和X-射线衍射等分析手段,着重探讨了该晶相的形成条件和分解条件,分析了该晶相发生转变的过程和机理。结果发现该晶相在330℃下能够稳定存在,而在330～340℃之间则会分解成Na_2O·4TeO_2(NT_4)和TeO_2两种晶体。在由NT_8向NT_4和TeO_2的转变过程中出现了两个热效应,先是一个吸热反应,然后是一个放热反应,这说明在NT_8向NT_4和TeO_2的转变过程中,出现了一个中间相,该中间相为一种非晶相。作者认为,NT_8向NT_4和TeO_2的转变分为两个步骤,第一步是由NT_8向中间非晶相的转变,第二步是中间非晶相向NT_4和TeO_2的转变,而且由NT_8向中间相转变的过程与由中间相向NT_4和TeO_2转变的过程是同时进行的。

电极材料在铁磷酸盐玻璃熔体内腐蚀现象的研究

选用合金Inconel690和693作为研究对象,着重研究了它们在铁磷酸盐玻璃熔体中的腐蚀行为。分别计算了不同电极材料的尺寸损失和质量损失,以及相应的损失速率,采用SEM,EDS和XRD等手段对材料表面的腐蚀层进行了分析,确定了腐蚀层的成分,主要相组成及其晶粒形态,讨论了材料腐蚀发生的可能机理。结果表明,在玻璃熔体内,合金Inconel693比Inconel690更耐腐蚀。随着腐蚀时间的延长,合金的腐蚀速率都逐渐降低。合金试样表面的腐蚀层主要由固熔体(Fe,Cr)2O3组成。

焊接方法对Ti-6Al-4V合金接头微观组织及拉伸和冲击性能的影响(英文)

钛合金由于具有高比强度、优越的耐腐蚀性和出色的耐热性等优良特性,已成功应用于航空航天、造船和化学工业。尽管钛合金具有合适的可焊性特点,但焊接方法极大地影响焊接接头性能。焊接过程中热循环将会影响焊接金属凝固、相转变和微观组织。采用钨电极惰性气体保护焊接(GTAW)、激光束焊接(LBW)和电子束焊接(EBW)方法制备Ti-6Al-4V合金的焊接接头。EBW焊接接头的强度高于GTAW和LBW接头的强度,但GTAW接头较其它两种接头具有较高的断裂韧性。焊接接头的拉伸和冲击性能与焊接金属的微观组织有关。

Effect of Layered Double Hydroxides on Ultraviolet Aging Resistance of SBS Modified Bitumen Membrane

Layered double hydroxides(LDHs)/styrene-butadiene-styrene(SBS) copolymer modified bitumen was prepared by melt blending. The effect of LDHs on the ultraviolet(UV) aging behavior of SBS modifi ed bitumen was investigated. The changes of chemical structures of modifi ed bitumen before and after UV aging were characterized by Fourier transform infrared spectroscopy(FTIR). The results show that LDHs obviously reduce the variation of softening point and low temperature fl exibility of SBS modifi ed bitumen under different UV radiation intensities, which indicates that the UV aging resistance performance of SBS modifi ed bitumen is improved effectively by LDHs. Compared with SBS modifi ed bitumen, the changes of carbonyl, sulfoxide and butadienyl of LDHs/SBS modified bitumen decrease significantly after UV aging according to FTIR analysis, demonstrating that the oxidation and degradation reactions of SBS modifi ed bitumen were restrained effectively by adding LDHs.

Preparation of High-Density Nanocrystalline Bulk Selenium by Rapid Compressing of Melt

melt 元素的硒的团结行为被一系列实验包括分别地的在 20ms 以内的到 2.8 和 3.5 GPa 的快速的压缩调查，为 20 min 并且在周围的压力的自然冷却的慢压缩到 2.8 GPa。基于X光衍射，扫描恢复样品的电子显微镜和传播电子显微镜结果，同质的 nanostructures 仅仅由快速的压缩过程被形成，这清楚地被显示出，并且平均水晶尺寸是在样品的大约 18.7 和 19.0 nm ，这分别地从 2.8 和 3.5 GPa 恢复了。nanocrystalline 体积的相对密度到达 98.17% 理论价值。快速的压缩能导致弥漫的成核并且在团结期间制止谷物生长，这被建议，它与快 supercooling， melt 的更高的粘性和在高压力下面的原子的更低的扩散性有关。

A Study of Chromium Adsorption on Natural Goethite Biomineralized with Iron Bacteria

针铁矿，特别源於生物的针铁矿，包括金属离子为许多沾染物的吸附有高比面积区域和大能力，器官的 cnelates.Chromium 是一条消遣哈鱼是存在的活跃地有毒的金属离子Cr^( III )或在自然的Cr^( VI )，并且作为这，理解它自然针铁矿上的吸附的行为由铁化菌使矿物化，，必要在水团的 Gallionella 和 Leptothrix 。Cr^(3+)andCr^(VI ) 在上的吸附自然地，简历使矿物化针铁矿在这篇论文被学习。结果显示出等温的模型是的那 bothLangmuir 和 Freundlich 吸附能精确地描述这二个离子的吸附。 SEM/EDS 的调查， TEM/EDS 显示二个离子由于针铁矿的不同微观结构在针铁矿上不 adsorbhomogeneously 做，并且那个 themicrospherical 针铁矿比简历的表面上的铬的氧化还原反应使矿物化的螺旋状的 one.XPS 数据表演为铬离子有一个更大的吸附能力针铁矿发生在Cr^(3+)和Cr^( VI )的吸附。在 bio-goethite 上吸附的 Cr^(VI ) 容易得多在 bio-goethite 上比 Cr^(III ) 的氧化转变成 Cr^(III ) 。

Second-harmonic Generation in UV-pulsed Laser Poled Amorphous 80GeS_2-15Ga_2 S_3-5CdS Chalcogenide Film

With the pulsed laser deposition(PLD) method, amorphous 80GeS 2-15Ga 2 S 3-5CdS chalcogenide film was deposited on glassy substrate. Obvious second harmonic generation(SHG) was observed in the ultraviolet(UV)-polarized film and the SHG intensity increased with the increase in single pulse energy and irradiation time. Through Raman spectra and transmission spectra, the mechanism of SHG was studied. The experimental results demonstrated that effective electron traps and hole traps were generated in the UV- polarized film. The energy of electrons and holes was using up due to the collision with other particles and crystal fields during their movement and finally they were captured by the traps and fixed, which made the electric charge distribution nonuniform in the film and destroyed the spatial isotropy. In the meantime, the center of positive and negative charges separated and a built-in electric field was formed which generated the optical second-order nonlinearity of the film.

Magnetic Properties and Nanostructures of FePtCu：C Thin Films with FePt Underlayers

FePtCu 的磁性和 nanostructures : 有 FePtunderlayers (UL ) 的 C 薄电影被学习。薄电影的取向和磁性上的 FePt UL 的效果被以 14 nm 从 2 nm 调整 FePt UL 厚度调查。X-raydiffraction (XRD ) 扫描表明榆树的取向依赖于 FePt UL 厚度。为 5-nm FePtCu : C nanocomposite 有 2-nm FePt UL 的薄榆树， coercivity 是 6.5KOe ，关联长度是 59nm ，需要的 lace-centred-tetragonal ( fct )订了结构[ L1 ( 0 )阶段]被形成并且 c 轴正常到榆树飞机[( 001 )质地]被获得。这些结果显示这些电影的更好的取向和磁性能被减少调节 FePt UL 的厚度。

Preparation of Intercalated Clay/Phenolic Resin Nanocomposites under High Pressure

High pressure method was used for the first time to produce rectorite clay (REC) /phenolic resin (PF) and organic rectorite clay (OREC) /phenolic resin and montmorillonite(MMT)/phenolic resin (PF) nanocomposites. The structure of the material phase was studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), and atomic force microscopy (AFM). The experimental results show that intercalated clay/resin nanocomposites could form under normal temperature and high pressure conditions by the intercalation of polymeric molecules rather than interlayer polymerization.