纳米粘土增强环氧树脂复合材料抗原子氧性能的研究（英文）

本文采用激光爆破法高能原于氧束源研究了纳米粘土增强坏氧树脂复合材料的抗原子氧性能.研究了四种样品:纯环氧树脂,纳米粘土含量为1 wt%,2 wt%和4 wt%的纳米粘土增强环氧树脂复合材料,结果表明腐蚀深度随着纳米粘土含量的增加而降低,当掺杂纳米粘土含量为4 wt%时,腐蚀深度为纯环氧树脂腐蚀深度的28%～37%;X射线光电子能谱(XPS)分析表明原子氧轰击后,材料表面C-C/C-H键比例减少,C-O键、酮类比例增加,表面氧化程度增加,掺杂纳米粘土的材料表面生成了新的碳酸盐,掺杂4 wt%纳米粘土的复合材料表面氧化程度增加最小;扫描电子显微镜(SEM)结果显示含有纳米粘土的复合材料表面被原子氧轰击后在纳米粘土团簇处形成了"块状"物质,掺杂4 wt%纳米粘土的复合材料,"块状"物质尺寸和分布密度最大;综合腐蚀深度,XPS,以及SEM结果表明,虽然所有表面都一定程度地被原子氧腐蚀和氧化,但掺杂纳米粘土的复合材料表面由于生成了"块状"物质,阻挡了原子氧进一步腐蚀其下的材料,提高了抗原子氧性能.     

包覆镍铁氧体纳米粒子的空心玻璃微珠复合材料的制备与电磁性能研究

"用高分子凝胶法制备了包覆镍铁氧体纳米粒子的空心玻璃微珠复合材料．玻璃微珠含量为25%、50%和75%的复合粉的结构、表面形貌和电磁性能分别用X射线衍射仪、扫描电镜、能谱仪、红外光谱和HP8510网络分析仪来表征．结果表明,复合粉由镍铁氧体、石英和莫来石相组成．随着微珠含量的增加,镍铁氧体衍射峰强度迅速降低,莫来石衍射峰强度迅速增强．当温度达到800 ℃时,纯尖晶石结构的镍铁氧体在玻璃微珠表面生成．当玻璃微珠含量为50%时可获得均一、连续的镍铁氧体涂层．大部分镍铁氧体粒子的尺寸小于80 nm．玻璃微珠含量     

纳米粘土增强环氧树脂复合材料抗原子氧性能的研究

本文采用激光爆破法高能原子氧束源研究了纳米粘土增强环氧树脂复合材料的抗原子氧性能. 研究了四种样品：纯环氧树脂,纳米粘土含量为1 wt%,2 wt%和4 wt%的纳米粘土增强环氧树脂复合材料,结果表明腐蚀深度随着纳米粘土含量的增加而降低,当掺杂纳米粘土含量为4 wt%时,腐蚀深度为纯环氧树脂腐蚀深度的28%∽37%;X射线光电子能谱(XPS)分析表明原子氧轰击后,材料表面C-C/C-H键比例减少,C-O键、酮类比例增加,表面氧化程度增加,掺杂纳米粘土的材料表面生成了新的碳酸盐,掺杂4 wt%纳米粘土的复合材料表面氧化程度增加最小;扫描电子显微镜(SEM)结果显示含有纳米粘土的复合材料表面被原子氧轰击后在纳米粘土团簇处形成了“块状”物质,掺杂4 wt%纳米粘土的复合材料,“块状”物质尺寸和分布密度最大;综合腐蚀深度,XPS,以及SEM结果表明,虽然所有表面都一定程度地被原子氧腐蚀和氧化,但掺杂纳米粘土的复合材料表面由于生成了“块状”物质,阻挡了原子氧进一步腐蚀其下的材料,提高了抗原子氧性能.     

工业纯钛微弧氧化膜的结构及拉曼光谱分析

采用微弧氧化技术,用处理电压为300, 350, 400, 450, 500 V在工业纯钛表面制备了5块氧化膜试样,利用扫描电镜和拉曼光谱研究了处理电压对氧化膜结构的影响。结果表明：氧化膜表面布满了微孔,其尺寸随处理电压的升高而增加,而微孔密度则呈相反的变化趋势。氧化膜主要由锐钛矿和金红石相组成,其相含量与处理电压的大小密切相关。当处理电压较低时,氧化膜主要由锐钛矿相组成; 随着处理电压的升高,氧化膜中金红石相的相对含量增加; 当处理电压在400～450 V时,金红石相含量增加迅速,并成为主晶相。     

细胞色素c甲硫氨酸氧化机制的NMR研究

细胞在呼吸作用中产生活性氧，活性氧含量处于低水平时有利于信号传导，累积过量时会引发蛋白质氧化修饰．细胞色素c是位于线粒体内的多功能金属蛋白，其发生氧化修饰特别是甲硫氨酸Met80的亚砜化修饰可能影响蛋白构象变化，但其机制仍不清楚．本研究通过13C选择性标记细胞色素c上甲硫氨酸的末端甲基，利用液体核磁共振技术，追踪了细胞色素c在氧化环境中的氧化修饰变化．发现在氧化环境中，该蛋白质先由还原态转化为氧化态，当活性氧达到一定量时，再发生甲硫氨酸Met80的亚砜化修饰，但在活性氧作用初期未导致明显的蛋白结构变化．这表明细胞色素c具有一定抵御活性氧的作用．     

紫外光下毛竹的自由基与光电子能谱分析

分析了紫外光照射下毛竹自由基的变化规律和表面化学组成及结构的变化.利用电子自旋共振波谱和X射线光电子能谱技术,分别测量紫外光辐照后毛竹颗粒的自由基波谱和X射线光电子能谱.结果表明:毛竹自由基的光谱分裂因子g=2.003 3,自由基的强度随着辐照时间按Y=1-e-b,Pt规律增加;紫外光照60 min后毛竹表面O/C原子比稍有增加,C-C和C-H含量增加,C-O和C=O含量减少,-O-C=O含量增加为原来的3倍左右,说明毛竹表面生成了一些含氧官能团或碳的氧化态增高.     

基于Raman与FTIR对掺甲烷乙烯/氢气扩散火焰碳烟有序度和官能团的研究

以甲烷、乙烯、氢气混合扩散火焰碳烟为研究对象,采用激光共聚焦拉曼光谱（Raman）和傅里叶红外光谱（FTIR）研究了不同掺甲烷比例下乙烯、氢气混合火焰碳烟有序度及官能团的分布特性,分析了碳烟石墨化和官能团分布,揭示了掺甲烷对乙烯/氢气（氢气比例30%）层流扩散火焰的碳烟生成影响规律。Raman研究表明在甲烷掺混比为3%和7%时,在火焰高度低于4cm位置生成的碳烟有序程度显著降低,表明在此区域存在明显的碳烟生成协同效应;甲烷掺混比增大超过10%时,协同效应基本消失,碳烟有序度上升。FTIR研究表明掺混甲烷对碳烟官能团组成影响明显。掺混甲烷后脂肪族官能团相对含量整体提高。随着甲烷掺杂比的增大,CH₂相对含量增大到一峰值后减小。碳烟中芳香族官能团含量随着火焰高度的上升含量下降明显。掺混3%和7%甲烷,芳香族官能团在2和3 cm火焰高度时,芳香族官能团的含量明显上升。掺混甲烷比高于10%时,芳香族官能团的含量则有所降低。表明少量甲烷掺混使得CH₃和C₃H₃生成有了新的途径,CH₃和C₃H₃增加,而C₂H₄和C₂H₂减少不明显,从而促进了多环芳香烃(PAHs)的生成。继续增加甲烷因为稀释作用会抑制C₂H₂生成从而减少PAHs的生成,芳香族相对含量降低,因而降低了碳烟的生成。研究揭示了甲烷对乙烯/氢气层流扩散火焰中碳烟形成的相互作用：在低甲烷掺混比时存在协同效应促进碳烟生成,而在高甲烷掺混比时协同效应消失。     

紫外光下毛竹的自由基与光电子能谱分析

分析了紫外光照射下毛竹自由基的变化规律和表面化学组成及结构的变化.利用电子自旋共振波谱和X射线光电子能谱技术,分别测量紫外光辐照后毛竹颗粒的自由基波谱和X射线光电子能谱.结果表明:毛竹自由基的光谱分裂因子g=2.003 3,自由基的强度随着辐照时间按Y=1-e^-b_iPt规律增加;紫外光照60 min后毛竹表面O/C原子比稍有增加,C-C和C-H含量增加,C-O和C=O含量减少,-O-C=O含量增加为原来的3倍左右,说明毛竹表面生成了一些含氧官能团或碳的氧化态增高.     

少量氧气对大气压氩氧混合气体放电特性的影响

基于一维流体模型,采用数值模拟的方法研究了大气压氩氧混合气体放电中少量氧气含量对放电特性的影响。根据模型方程进行了数值模拟分析,计算结果表明：随着氧气含量由0.1%增加到0.6%,电子密度减小,O^-离子密度增加,总的负粒子密度增加,鞘层区电子温度增加。随着放电时间的增加,O^-离子密度增加,电子密度的变化分为三个阶段：电子密度快速增长阶段、电子密度下降阶段和电子密度稳定阶段。当氧气含量小于1%时,电子密度随着氧气含量的增加迅速减小,氧原子密度快速增加;氧气含量大于1%小于4%时,电子密度随氧气含量的增加而缓慢减少,氧原子密度缓慢增加直至不变。     

Enhancement in Magnetorheological Effect of Magnetorheological Elastomers by Surface Modification of Iron Particles

为了研制具有高磁流变效应的磁流变弹性体,从新的化学修饰的角度制备了各向异性的橡胶基磁流变弹性体. 阴离子表面活性剂、非离子表面活性剂和复合表面活性剂等三种不同类型的表面活性剂分别用于修饰铁颗粒. 使用力磁耦合动态测试仪测量磁流变弹性体的动态剪切模量,并计算材料的磁流变效应. 测试结果表明,当Span 80的含量为15%时,材料的相对磁流变效应可达到188%,除了表面活性外,Span 80的增塑效应也有利于相对磁流变效应的增加. 当使用具有强表面活性的复合表面活性剂修饰铁颗粒时,用量只需0.4%,便可使相对     

铜导线短路熔痕的XPS研究

利用氩离子溅射对熔痕样品进行了深度刻蚀,同时利用Cu的俄歇谱线和计算的俄歇参数值,对不同环境形成的铜导线短路痕迹的物相及元素分布规律进行了分析。根据刻蚀时间可将一次短路熔痕表面膜层分为三部分,即C含量迅速减少的近表面层;O含量变化不大,C含量逐渐消失且有Cu₂O相的中间层;无Cu₂O相,O含量显著减少的过渡层。而将二次短路熔痕表面膜层分为两部分：C含量迅速减少的近表面层;无Cu₂O相,C和O量逐渐减少层。由此可见,一次短路熔痕的表面膜层与基体分界明显,有显著的过渡层,而二次短路熔痕的表面膜层与基体分界不明显,无过渡层。综上所述,可以根据两种短路熔痕是否含有Cu₂O相以及定量分析结果来区分两种熔痕,为判断火灾原因提供新的技术依据。     

原位DRIFTS研究CH4部分氧化和CO2重整的耦合

8%Ru-5?/γ-Al2O3催化剂对于甲烷的低温活化具有较好的催化活性,在500℃下甲烷、二氧化碳和氧气的耦合反应中,吸热反应二氧化碳重整和放热反应甲烷部分氧化进行耦合强化,使得耦合反应中的甲烷转化率为38.8%。用原位漫反射傅里叶红外光谱法对钌系催化剂耦合甲烷部分氧化和二氧化碳重整反应体系机理进行研究。CO在8%Ru-5?/γ-Al2O3上吸附,表明CO在催化剂表面上波数为2 167 cm-1(2 118 cm-1)和2031 cm-1(2 034 cm-1)处形成孪生态Ru(CO)2和Ce(CO)2吸附物种,而且高温下CO吸附物种很容易从催化剂表面脱附出来。原位漫反射红外实验结果表明甲烷部分氧化反应时催化剂表面上有吸附物种碳酸根、甲酰基(甲酸盐)和一氧化碳的形成,其中表面的甲酰基和甲酸盐物种是甲烷部分氧化反应的主要活性中间物,这些中间活性中间体由甲烷吸附态CHx和催化剂表面的氧吸附态结合而形成的,随后这种中间物种再分解为CO产物;甲烷和二氧化碳重整反应时没有新的吸附物种产生,由此提出重整反应的机理是吸附态的甲烷和二氧化碳在催化剂活性中心上进行活化解离而生成合成气;甲烷、二氧化碳和氧气耦合反应过程中出现新的羟基物种(桥式羟基Ru-(OH)2),耦合反应机理复杂可能是由部分氧化和重整两类反应机理的复合,其中桥式羟基Ru-(OH)2参与了反应的进行。     

基于SEM与XPS对焦炉上升管内壁结焦炭层织构的研究

以焦炉上升管内壁结焦炭层为研究对象,采用扫描电子显微镜（SEM）和X射线光电子能谱仪（XPS）研究各结焦炭层的微观形貌、元素组成及键合状态,分析结焦炭层织构形成及演化规律。SEM研究表明,焦炉上升管内壁各结焦炭层形貌呈现较大的差异性,1#结焦炭层呈现0.1～1.0 μm颗粒化炭颗粒松散堆叠的多孔结构, 2#和3#结焦炭层呈现粒径为 1.0～3.0 μm 的炭颗粒堆积形貌且致密性有所提高,4#结焦炭层呈现大量花纹状致密结构。以上现象可说明结焦炭层的形成过程为：首先由荒煤气中多环芳烃形成0.1～1.0 μm的颗粒状初级炭层,颗粒状初级炭层在荒煤气粉尘中金属元素（如Fe）的催化作用下相互反应,形成更为致密的1.0～3.0 μm的中级炭层结构,中级炭层在高温条件下进一步形成致密的终级炭层结构。XPS分析表明,1#-4#结焦炭层含C量分别为91.78%,91.95%,92.74%和94.01%,含O量分别为5.58%,5.42%,4.39%和2.86%,C/O比分别为16.45,16.96,21.12和32.87,说明在炭层结构变化的同时,炭层中含氧基团在高温及粉尘中金属元素（如Fe）作用下发生脱除反应,使得炭层中宏观C/O比逐渐升高。在此基础上,通过对C元素键合状态分峰发现,1#-4#结焦炭层中C-C/C-H结构含量分别为80.42%,78.00%,75.50%和81.29%,C-O/C-N结构含量分别为10.22%,11.93%,13.54%和9.35%,C═O/C═N结构含量分别为9.36%,10.07%,10.96%和9.36%。O元素键合状态分峰发现,1#-4#结焦炭层中═O结构含量分别为20.40%,22.21%,19.93%,18.36%,-O-结构含量分别为24.60%,27.80%,31.35%,37.82%,O₂/H₂O结构含量分别为55.00%,49.99%,48.72%和43.82%。以上现象说明结焦炭层上发生如下化学变化：初级炭层中多孔结构会吸附荒煤气中的氧气（O₂）和水分子（H₂O）在高温条件下对炭层进行氧化。脱除反应和氧化反应使得炭层中O元素在微观键合状态发生明显改变,最终使得炭层中O₂/H₂O和═O结构含量降低,-O-结构含量升高。以上研究揭示了荒煤气上升管结焦炭层织构形成及演化机制,为解决焦炉荒煤气上升管内壁结焦问题,提高换热器效能,降低焦化企业能耗提供了实验基础和理论依据。     

XPS investigation on Upilex-S polyimide ablated by pulse TEA CO2 laser

Laser ablation of Upilex-S polyimide films 80 μm thick was performed in air using a pulse TEA CO₂ laser with wavelength 9.3 μm. A halo surrounding the hole was observed, which is covered with sub-micro particles. Pieces of ablation products protrude from the ablated surface, leading to considerable roughness of the ablated area. Chemical and structural changes of Upilex-S polyimide film surface irradiated by the pulse TEA CO₂ laser in air were analyzed by X-ray photoelectron spectroscopy (XPS). Relative C content in the ablated area was found to be higher, whilst both O and N contents were lower than in the untreated area. This means that TEA CO₂ laser ablation released both the O and N atoms. Also, the peak areas corresponding with carbonyl group (C=O) in the imide system were reduced much more and a new component at 287.0 eV assigned to the amide structure (N---C=O) was detected after laser ablation. These suggest that the pyrolysis of the Upilex-S polyimide was the decomposition of the imide ring between the nitrogen/aromatic carbon atom and carbonyl carbon atom. In addition, another new component arising from >C=O groups was also detected for higher fluence (7.83 J/cm²), and its peak areas is very small. This result indicates that the slight oxidation may take place with higher fluence during laser ablation in air. Based on above-mentioned experimental results, a possible thermally-induced decomposition path of Upilex-S polyimide ablated by TEA CO₂ laser is presented.     

Surface state of TiO2 treated with low ion energy plasma

The effect of low pressure radio frequency (rf) plasma treatment on TiO₂ surface states has been studied using X-ray photoelectron spectroscopy. Three different oxidation states of oxygen in untreated TiO₂ powder were observed, which suggests the existence of adsorbed water and carbon on the surface. The ratio of oxygen to titanium (O/Ti) was decreased for the low ion dose plasma treated samples due to desorption of water from the surface. In the case of Ti 2p about 20% of surface states were converted to Ti³⁺ 2p_3/2 state after plasma treatment with a very good stability, whereas untreated TiO₂ remained mostly as Ti⁴⁺ state. A rapid decrease in the ratio of carbon to titanium (C/Ti) at TiO₂ surface was also observed after plasma treatment and more than 90% of carbon atoms were removed from the surface. Therefore, the plasma treatment of TiO₂ has advantages to surface carbon cleaning, increasing O⁻ and Ti³⁺ surface states, hence improving the activity of TiO₂ for different environmental, energy and biological applications.     

SiC/SiO2 coating for improving the oxidation resistive property of carbon nanofiber

The SiC/SiO₂ deposition was performed to improve the oxidation resistive properties of carbon nanofiber (CNF) from electrospinning at elevated temperatures through sol-gel process. The stabilized polyacrylonitrile (PAN) fibers were coated with SiO₂ followed by heat treatment up to 1000 and 1400 °C in an inert argon atmosphere. The chemical compositions of the CNFs surface heat-treated were characterized as C, Si and O existing as SiC and SiO₂ compounds on the surface. The uniform and continuous coating improved the oxidation resistance of the carbon nanofibers. The residual weight of the composite was 70-80% and mixture of SiC, SiO₂ and some residual carbon after exposure to air at 1000 °C.     

Enhancement of saccharin removal from aqueous solution by activated carbon adsorption with ultrasonic treatment

This study investigates the use of ultrasonication as a pretreatment process and its effect on the adsorption characteristics of saccharin onto activated carbon (AC). Ultrasonic decomposition of saccharin was performed at a frequency of 500 kHz under argon and O2/N2 (20/80 vol%) atmospheres. Adsorption was carried out using a commercial activated carbon. The behavior of total organic carbon (TOC) during ultrasonication was investigated. Saccharin removal after 180 min of ultrasonication under Ar and O2/N2 atmospheres are 38% and 26%, respectively, while the amount of saccharin removed by activated carbon adsorption without US pretreatment is 40% after 16 h. After 16 h of AC adsorption with 180 min of ultrasonic pretreatment under Ar and O2/N2 atmospheres, both removal ratios increased to 75%. These results indicated that the pretreatment of sonication under O2/N2 leads to the increase in the amount of saccharin adsorbed on AC. On the other hand, the TOC removal by decomposition by ultrasound is not more than 5% in both Ar and O2/N2 atmospheres after 180 min ultrasonication. However, the TOC removal increased to 54% and 69% after 16 h of adsorption of saccharin pretreated by ultrasonication for 180 min under Ar and O2/N2 atmospheres, respectively. About 13% and 16% TOC removal in Ar and in O2/N2, respectively, were achieved due to adsorption of the by-products. It is considered that the improvement in TOC removal is also brought about by the formation of the by-products that were adsorbed onto AC.     

陕北侏罗纪富镜煤和富惰煤分子结构的FTIR，XPS和13C NMR表征

侏罗纪优质煤炭资源为煤制油、制气等清洁高效利用提供了丰富的物质基础,其显微组分以富集惰质组为特征,而镜质组与惰质组大分子结构在很大程度上决定了煤的物理化学性质和工艺性能,进而决定了煤炭资源的综合利用效率及附加值。采集并制备了陕北侏罗纪煤田小保当煤矿和柠条塔煤矿的原煤(XR)、富镜质组煤(XV、NV)和富惰质组煤(XI、NI)样品,利用傅里叶变换红外光谱(FTIR)、X射线光电子能谱(XPS)、固体13C核磁共振谱(13C NMR)等手段,结合煤质分析结果,定量表征了不同显微组分富集物分子结构的差异。研究结果表明：XI和NI煤中芳烃结构芳环取代程度低,主要以3个相邻、4~5个相邻的氢原子形式存在,苯环上氢原子较少被其他官能团取代,同时其结构中芳烃C═C骨架振动明显,脂肪结构中亚甲基伸缩振动强度较低,并且甲基含量略高于富镜煤,C═O基团相对含量略高,表明富惰煤有较多含氧桥键相连的芳香结构,其结构中脂族链、脂环基团脱落、断裂以及芳烃富集,支链相对较少且长度较短,芳碳率、芳香度、芳环缩合程度及成熟度较高。XV和NV煤中表面结构中碳的赋存形态“C—C,C—H”,“C—O”的相对含量高于富惰煤,反映其结构中应含较多的芳环取代的脂肪族侧链,XI和NI煤表面结构中氧的赋存形态以“C—O”为主,“C═O”和“COO—”明显高于富镜煤。XV和XI煤的芳碳率分别为57.91%和66.02%,脂甲基碳分别为10.02%和7.84%,质子化芳碳为非质子化芳碳的两倍,XV煤的羰基和羧基碳相对含量较高,两者桥碳和周碳之比分别为0.25和0.40,芳香核结构平均缩合环数分别为2.68和3.03,平均尺寸分别为0.448和0.676 nm,XI煤结构中芳香核以萘和蒽为主,支链化度L_γ分别为0.22和0.19,表明XV比XI存在较多脂肪侧链、饱和环结构,生烃(油)潜力大。     

Surface cleaning and preparation in AlGaN/GaN-based HEMT processing as assessed by X-ray photoelectron spectroscopy

The chemical composition of the AlGaN/GaN surface during typical process steps in transistor fabrication was studied using X-ray photoelectron spectroscopy (XPS). The steps studied included organic solvent cleaning, 1:1 HCl:H₂O dip, buffered oxide etch dip, oxygen plasma descum and rapid thermal annealing (RTA). The surface composition was calculated after correction for the interference of the Ga Auger lines in the N 1s portion of the spectra. The buffered oxide etched (BOE) surface showed a greater tendency for Al (compared to Ga) to be oxidized in the surface, under a layer of adventitious carbon. Three different treatments were found to yield a combination of low C and O levels in the surface. Both plasma cleaning and RTA were highly effective at reducing the carbon contamination of the surface, but did increase the oxygen levels. The RTA treated surface was found to have low levels of oxygen incorporation to a depth of 2-6 nm.     

Determination of adsorbate coverages by leed and XPS

Layers of carbon, oxygen, sulfur and potassium adsorbed on an Fe(100) surface were studied by LEED, AES and XPS. When examined quantitatively by XPS, saturated c(2 × 2)CO(β), c(2 × 2)C and p(1 × 1)O surface structures yielded the C/O ratios expected from surface coverages of 0.25, 0.5 and 1.0 monolayer, respectively. When these results were normalized to the equivalent coverages of 1.0 monolayer, the relative XPS cross-sections obtained for S, O, C and K were found to agree closely with the results of theoretical calculations. The results illustrate the use of these techniques for the quantitative determination of surface coverages.