基于中子活化瞬发伽马能谱确定地层元素含量的方法

中子技术能够利用中子与物质的相互作用确定其组成等性质,广泛应用于医学、环境科学、核反应堆建设、金属矿产勘查及石油工业中。在石油天然气领域,中子探测技术主要被用于确定井孔中的孔隙度、密度和流体饱和度等参数。随着测井技术的不断发展,基于瞬发伽马射线的中子活化分析技术也已应用于井下确定地层元素含量,并成为复杂岩性和非常规油气储层获得矿物含量的唯一手段。本文阐述了地层元素伽马能谱测井的方法,利用蒙特卡罗方法模拟了不同地层条件下的伽马能谱,构建了地层元素的标准谱库,研究了奇异值分解和极大似然估计能谱数据处理方法,并利用得到的元素产额及氧闭合模型实现地层元素含量的确定。利用蒙特卡罗方法构建已知地层的伽马能谱,采用上述数据处理方法得到元素含量与地层真实元素含量误差均在4%之内,Si元素误差最大为2.8%,Ca元素最大误差为3.3%,研究结果为井下确定地层元素成分及含量提供了有效的技术支持。     

化学溶液沉积法制备自取向BiFeO3多铁薄膜

通过化学溶液沉积法在氧化铟锡(ITO)/导电玻璃上生长了BiFeO₃多晶薄膜.利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱分析仪(XPS)、磁性测量系统(MPMS)和铁电测试仪对样品的结构、形貌、元素价态、铁磁性和铁电性进行研究.结果表明, 薄膜为自取向生长, 具有良好的[101] 生长取向和平整的表面.室温下, 样品呈铁磁性, 沿样品取向方向为易磁化轴方向.铁电测试结果表明, 其饱和电极化强度达到51.3 μC/cm².     

纳米氧化锰表面功能化木材的制备及性质

采用水热反应法制备了纳米氧化锰负载木材.通过扫描电子显微镜和能谱分析对样本进行了微观形貌和元素含量检测,并探讨了在不同处理条件下得到的纳米氧化锰负载木材在耐腐性和抗菌性方面的表现.数据分析显示,氧化锰负载木材的耐腐性和抗菌性均优于未处理的木材,水热反应中采用十二烷基硫酸钠作为表面活性剂时木材表面的氧化锰物相最纯净,且木材样本的性能优于其它条件下制备的样本.     

InGaAs薄膜电共沉积研究

本文应用优化工艺条件的电共沉积方法 ,制备发射光近于 1.3～ 1.5μm波长的InGaAs薄膜 .用能谱分析仪进行薄膜成分分析 ;分光光度计和单色仪测量薄膜的透射率 ,同时也测量了薄膜的V I特性、导电类型及其表面形貌 .     

PEG包覆涂层对含碳纤维导电剂的锂硫正极材料的影响

通过球磨混合及聚乙二醇（PEG）包覆处理制备含有高模量碳纤维（HMCF）的硫基复合材料.采用X射线衍射(XRD)和扫描电子显微镜(SEM)测定材料的结构和形貌,采用X-光电子扫描能谱（XPS）验证了PEG包覆在材料的表面,较系统地研究了PEG含量对含有高模量碳纤维的硫正极比容量、循环稳定性和倍率性能等性能的影响.结果表明：和常用的导电剂乙炔黑(AB)相比,HMCF导电剂具有结晶度高,接触角小,吸液性能好等优点.当PEG涂层量为1.09%时,硫正极初始放电容量为1312.5 mAh·g^-1,在电流密度为200 mA·g^-1充放电时,50次循环以后可逆容量保持为650 mAh·g^-1,和没有PEG涂层相比,循环稳定性提高了39.9%.     

热电池铁粉加热药燃烧产物特性

SEM(scanning electron microscope)、TEM(transmission electron microscope)形貌观察及XRD(x-raydiffraction)物相、EDX(energy dispersive X-ray detector)能谱分析表明,热电池用铁粉加热药经燃烧后其物相主要成分为Fe、FeO和KCl,并形成一层200 nm厚FeO壳层,该壳层包覆着未反应的Fe核.经导电类型鉴别确定室温下该材料具有以空穴导电为主的P型半导体导电特性.电导率103S.cm-1,比800 K时Fe的电导率低5个数量级.该材料虽具半导体导电特性,但并不增加热电池内阻.     

聚吡咯/多壁碳纳米管及其聚氨酯导电复合材料的制备和性能

以羧基化多壁碳纳米管(MWCNTs)做模版剂,采用化学氧化法将吡咯(Py)在羧基化MWCNTs表面聚合制备PPy/MWCNTs导电材料,将其添加到溶剂型聚氨酯(PU)溶液中制备了PPy/MWCNTs/PU导电复合材料,研究了Py用量对PPy/MWCNTs及其PU复合材料性能的影响.研究表明,随Py用量的增加,PPy/MWCNTs的长度不变,管径增大,sp~2和sp~3杂化C含量先提高后减少,N的掺杂梯度降低,PPy/MWCNTs的导电率高于羧基化MWCNTs和PPy.当Py用量为羧基化MWCNTs的20%时,其导电率最大.PPy/MWCNTs中N元素的掺杂程度及其管径变化是引起PPy/MWCNTs/PU复合材料的性能不同的主要原因.增加Py用量,MWCNTs中亲水的羧基因对PPy掺杂而消耗,相同导电材料用量时纳米导电粒子数目相对减少,PPy/MWCNTs/PU复合材料的耐水性能提高,定向应力、储能模量和玻璃化温度降低,导电率先增加后减小.当Py用量为羧基化MWCNTs的15%时,导电率最大.     

iPP/HDPE/CB三元导电复合材料的导电与流变行为

利用界面能原理使CB选择性分布于HDPE中成为复合导电相,固定CB在HDPE中的质量分数(20 wt％),控制CB/HDPE导电相在iPP中的含量,制备出一系列三元(iPP/HDPE/CB)导电复合材料,并研究其导电逾渗和流变逾渗行为.结果表明,在复合导电相含量为20 wt％时复合材料内即形成导电网络,在复合导电相含量30 wt％时出现流变网络.只有当复合导电相在材料中形成连续相时(60 wt％),损耗因子在频率扫描中才出现峰值.     

还原氧化石墨烯负载零价铁的合成及对TNT废水处理

选取比表面积大且导电性能优良的还原氧化石墨烯(rGO)作为支撑材料,负载还原性强但极易团聚的纳米零价铁(nZVI),制得还原氧化石墨烯负载零价铁(nZVI/rGO)复合材料.通过X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、扫描电子显微镜(SEM)与X射线光电子能谱(XPS)等测试手段对零价铁的负载情况、材料表面微观形貌与反应前后nZVI/rGO材料表面铁元素的含量与组成进行表征.考察了溶液初始pH值、材料投加量和理论零价铁负载量等因素对nZVI/rGO去除2,4,6-三硝基甲苯(TNT)的影响,研究了nZVI/rGO材料去除TNT的反应机理.通过正交实验可知, nZVI/rGO对含TNT废水的处理在较宽的反应条件范围内都可达到处理要求,在理论零价铁的负载量为3.0 g/g rGO,溶液初始pH为6,材料投加量为40 g/L时效果最佳,可将废水中TNT处理到检出限0.1 mg/L以下.     

含金属锡铟的导电银厚膜的抗氧化机理研究

通过在导电银电子浆料中添加适量的金属锡铟粉末,得到一种新的抗氧化银浆,并采用丝网印刷技术制备银厚膜.探讨了厚膜在自然时效氧化和硫化氢气氛中硫化氧化的过程及机理,采用扫描电子显微镜(SEM)、能谱(EDS)和X射线衍射(XRD)对银厚膜表面的微观形貌和元素成分进行分析.结果表明,含金属锡铟的银厚膜比纯银厚膜具有更好的抗氧化性.热力学分析表明,添加的金属锡铟与氧气、硫化氢反应的Gibbs自由能比纯银的小,更易在厚膜的晶界/孔洞缺陷处发生氧化反应,延缓银的氧化,从而提高银厚膜抗氧化能力.     

Soft lithography microfabrication of functionalized thermoplastics by solvent casting

A soft lithographic method is described for casting functional thermoplastic devices with microscale features without the need for specialized tools or equipment. In the thermoplastic soft lithography process, termed solvent casting, low temperature supersaturated solutions of thermoplastic are poured over solvent permeable PDMS molds which allow omnidirectional solvent removal as they template functional microstructures into the thermoplastic layers. Rapid gelation of supersaturated solutions enables the deposition of multiple patterned layers of varying composition, with self‐adhesion of the solvent‐laden thermoplastic ensuring intimate bonding between adjacent layers. This latter feature is further used in this work to realize sealed thermoplastic microfluidic devices with high fidelity replication of microchannel features with negligible channel deformation. The incorporation of functional dopants into patterned thermoplastic layers allows the fabrication of thermoplastic devices with embedded fluorescent sensors and integrated conductive elements. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1315–1323     

One-step process to make electrically conductive thermoplastic vulcanizates filled with MWCNTs

Electrically conductive thermoplastic vulcanizates(TPVs) filled by multi-walled carbon nanotubes(MWCNTs) are prepared by a simple one-step melt mixing process,based on linear low density polyethylene(LLDPE) and ultrafme full-vulcanized rubber particles(UFRP).An ideal morphology with controlled localization of MWCNTs in continuous LLDPE matrix and appropriate size of finely-dispersed UFRP can be achieved at the same time.The controlled localization of MWCNTs in the continuous phase facilitates the formation of conductive pathway,and thus the volume resistivity of the as-prepared LLDPE/UFRP/MWCNTs thermoplastic vulcanizates is significantly decreased.The results show that both the blend ratio of LLDPE/UFRP and the loading of MWCNTs have remarkable effect on the volume resistivity.Significantly, the electrically conductive TPVs exhibit good mechanical properties duo to the fine dispersion of UFRP in LLDPE.The added MWCNTs are capable of imparting reinforcement effects to thermoplastic vulcanizates with just a slight loss of stretchability and elasticity.     

Ag作催化剂制备的GaN的形貌及其性能

用化学气相沉积法(CVD)在Si(100)衬底上以Ag纳米颗粒为催化剂制备了微纳米结构的GaN,原料是熔融态的金属Ga和气态的NH3。采用X射线衍射仪(XRD)、透射电镜(TEM)、X-ray能谱仪(EDS)、场发射扫描电子显微镜(SEM)、光致发光能谱(PL)和霍尔效应测试对样品进行了结构、成分、形貌和发光、电学性能分析。结果表明:生成的自组装GaN为六方纤锌矿的类似小梯子的微纳米单晶结构,且在不同的温度下,GaN的发光性能和电学性能也有所不同,相对于强的紫外发光峰,其它杂质发光峰很微弱,且均呈p型导电。对本实验所得到的GaN微纳米结构的可能形成机理进行了探讨。     

Screening for Antimicrobials in Mouthwashes Using HPTLC-Bioluminescence Detection

One of the tasks of food law enforcement authorities is to supervise the composition of cosmetics. In the case of mouthwashes, they are likely to contain (labeled or unlabeled) antimicrobial compounds. Conventional analyses, such as high-performance liquid chromatography (HPLC) and gas chromatography (GC) only shed light on a compound’s structure, but not on its biological function. In this study, we demonstrate that the task of detecting antimicrobials in mouthwashes can be streamlined using the luminescent bacterium Vibrio fischeri as a biodetector coupled with high-performance thin-layer chromatography (HPTLC) as a pre-separation method. The employment of subsequent conventional techniques could then be restricted to fractions with proven V. fischeri toxicity. Samples were separated in parallel on silica gel and amino layer HPTLC plates, developed with a solvent system containing tertiary butyl methyl ether and n-hexane and dried on a plate heater. After applying V. fischeri onto the HPTLC plate, zones of interest were extracted from a parallel plate and identified by HPLC–UV or GC-mass spectrometry. The reaction of V. fischeri to more than 40 standard substances which might be present in mouthwashes was determined. Based on this information, six commercially available mouthwashes were analyzed. The workflow proved to be viable for an effect-directed screening for antimicrobial compounds. The analysis of mouthwashes revealed that not only declared preservatives are used (sodium benzoate, cetylpyridinium chloride) but also other compounds, especially constituents of essential oils. Because their main purpose is flavoring of the mouthwash, they are summarized as “aroma” (anethole, carvone, menthol, thymol) which is in compliance with legal restrictions.     

Kinetics of copper slag oxidation under nonisothermal conditions

The kinetics of air copper slag oxidation under nonisothermal conditions is studied using simultaneous TG–DTA at a varying heating rate of slag and flow rate of the oxidizing gas flux. The values of the kinetic parameters, activation energy and pre-exponential factor, have been determined based on: data from DTA by the methods of Kissinger and Ozawa; data from TG using an isoconversion method and the computation procedures of Ozawa–Flynn–Wall and Kissinger–Akahira–Sunose. No relationship between the kinetic parameters and the oxidation gas flow rate has been established. The changes of the phase composition with temperature are investigated by X-ray powder diffraction analysis on the basis of data obtained for the products formed at the different stages of the oxidation process. The morphology of the oxidized slag as well as the elements distribution is studied by electron microscopy and EDS analysis.     

Thermoset modified with polyethersulfone: Characterization and control of the morphology

Thermoset (TS) epoxy resins can be toughened with a thermoplastic (TP) for high-performance applications. The final structure morphology has to be controlled to achieve high mechanical properties and high impact resistance. Four polyethersulfone-modified epoxy resins are considered. They consist of different epoxy monomer structure (TGAP, triglycidyl-p-aminophenol and TGDDM, tetraglycidyl diaminodiphenylmethane) and a fixed amount of thermoplastic, and they are cured with two different amounts of curing agent. A reaction-induced phase separation occurs for all formulations generating morphologies, different in shapes and scales. The aim is to control the final morphology and in particular its dominant length scale. This morphology depends on the phase separation process, from the initiation to its final stage. The initiation relies on the relative miscibility of the components and on the stoichiometry between epoxy and curing agent. The kinetics depends on the viscosity of the systems. The different morphologies are characterized by electron microscopy or neutron scattering. Dynamic mechanical analysis allows confirming the presence of a phase separation even when it is not observable by electron microscopy. Vermicular morphologies with few hundreds nanometer width are obtained for the systems containing the TGAP as epoxy monomer. Systems formulated with TGDDM presents morphologies on much smaller scale of order a few tens of nanometers. We interpret the different sizes of the morphologies as a consequence of a larger viscosity for the TGDDM systems as compared to the TGAP ones rather than by a latter initiation of phase separation.     

Evaluation of phenyldimethylethoxysilane treated high-performance thin-layer chromatographic plates. Application to analysis of flavonoids inScutellariae radix

Summary The retention and selectivity of flavonoids (baicalin, baicalein, wogonin, oroxylin A) inScutellariae radix have been studies by high-performance thin-layer chromatography on phenyldimethylethoxysilane-treated silica plates. The silica plates treated with phenyl groups were used for physical and chemical analysis. From elemental carbon analysis, the maximum number of bonded phenyl surface groups per gram was calculated to be 0.467×10²¹ (Oginal silica plate: Merck Art. 15109, Silica gel 100 F₂₅₄). With methanol-1/15 M phosphate buffer (pH 6.2) mixtures as mobile phase, baicalin, baicalein, wogonin, and oroxylin A inScutellariae radix were separated. It has been shown that phenyl-treated plates are more suitable for selective separation of baicalin, baicalein, wogonin, and oroxylin A than octadecyl-treated plates.     

Surface properties and corrosion resistance of SF6 plasma‐treated polyester‐based thermoplastic elastomer

Copolyester thermoplastic elastomers (COPE) have interesting mechanical properties but low chemical resistance in aggressive environments. Developing a treatment that would increase their chemical resistance while preserving their convenient bulk characteristics would be an advance. Radiofrequency plasma treatments in sulfur hexafluoride were undertaken. Surface properties and corrosion resistance of untreated and treated samples were investigated. Surface chemical composition was altered, resulting in a loss of organic elements and the incorporation of fluorine. Surface morphology and topography were changed by the removal of species during the treatment. Treatment tends to increase hydrophobicity; for the longer treatment times, hydrophobicity tends to be retained even after aging under atmospheric conditions. Resistance to chlorine attack was substantially increased upon fluorination, while resistance to oxygen attack was improved in some cases. The improvement in the corrosion resistance, which suggests an increase in lifetime under practical conditions, depends on fluorine incorporation and its effect on the physical stability of the structure.     

First Preparations and Characterization of Conductive Polymer Crystalline Nanoneedles

Single crystalline nanoneedles of three families of the most studied conductive organic polymers - polythiophene, polyaniline and polypyrrole - were synthesized for the first time using an interfacial polymerization process that takes place with simultaneous crystallization. As the crystal growth is concurrent with polymerization, more ordered crystal packing can be expected. Most of the bulk conducting-polymer systems studied contains regions that are inhomogeneous. Single nanocrystals of conducting polymers have not been reported, although needle-shaped bulk crystals of the quarterphenyl cation radical salt have previously been studied. The investigation of processes in a nanodomain of a single crystal is critical in ascertaining the inherent electronic properties of polymer nanoelements. The organic conductive nanoneedles were characterized using TEM, HRTEM, electron diffraction, EDS, and EPR to establish their crystal structure and composition. Scanning tunneling microscopy/spectroscopy (STM/STS) investigation were conducted to examine their electronic behaviors, leading to the discovery of a field-induced conductance switching with response times on the millisecond level. The switch voltages are in the range of 3 to 4 volts in STM experiments, consistent with the trend of the band gap of the three polymers. The organic conductive nanoneedles with nano-tip having high density of mobile electron may serve as interesting elements for nanoscale electronics.     

Standardless X-ray analysis of bulk specimens

The paper gives an overview of the problems of Standardless analysis of bulk specimens by energy dispersive spectrometry (EDS) in scanning electron microscopes (SEM). The interest is concentrated on the present (and future) developments. The influence of the fluorescence excited by the continuum is discussed. Some improvements are proposed for the ionization cross-section. The difficulties due to the Coster-Kronig radiationless transitions are mentioned for the L lines. Emphasis is put on the necessity of an accurate modelling of the detector window, in order to be able to calculate reliably the efficiency of detection, mainly for the ultra-light elements. It is shown that some hypotheses such as the continuity of the fluorescence yield with the atomic number, which are currently accepted for heavier elements, could be wrong in the field of ultra-light elements. The capability of Standardless analysis in special situations is discussed: analysis at oblique electron beam incidence, analysis of specimens with a thin conductive coating, analysis of stratified specimens.