碱溶ICP-AES法同时测定AlSi/SiC复合材料中的高含量硅和低含量镁、钛、铁

本文采用碱溶ICP-AES法对AlSi/SiC复合材料中的高含量硅和低含量镁、钛、铁的测定进行研究,着重进行基体元素铝及待测定元素硅、镁、钛、铁之间的干扰试验,进行了碱度试验和酸度试验,测定了AlSi/SiC复合材料中的硅、镁、钛、铁含量,得到了较好的精密度和准确度.方法简便可靠,可获得满意的分析结果.     

ICP-AES法测定铝合金中的Sc

本文采用ICP－AES法测定铝合金中的Sc，并讨论了基体元素及共存元素对Sc的干扰，进行了酸度试验，采用盐酸和硝酸溶解试样，回收率为96．0％－101．0％，RSD为0．31％－0．59％，方法简便，可靠，可获得满意的分析结果。     

碱溶ICP—AES法同时测定AISi／SiC复合材料中的高含量硅和低含量？…

本文采用碱溶ＩＣＰ－ＡＥＳ法对ＡＩＳｉ／ＳｉＣ复合材料中的高含量硅和低含量镁、钛、铁的测定进行研究,着重进行基体元素铝及特测定元素硅、镁、钛、铁之间的干扰试验,进行了碱度试验和酸度试验,测定和ＡＩＳｉ／ＳｉＣ复合材料中的硅、镁、钛、铁含量,得到了较好的精密度和准确度。方法简便可靠,可获得满意的分析结果。     

ICP-AES测定钛基复合材料中镍、钕和铁的研究

采用ICP－AES法对钛基复合材料中的合金元素镍、钕、铁的测定进行了研究，着重进行了基体元素及待测元素镍、钕、铁之间干扰试验及各元素在测定浓度范围内的线性相关性试验，进行了酸度试验，测定了钛基复合材料中3种元素的含量，得到了较好的精密度和准确度。方法简便、可靠，获得满意的分析结果。     

铸造锌合金中铝、铜、镁、铁、硅、镉的 ICP-AES法测定

采用ICP-AES法测定了铸造锌合金的铝、铜、镁、铁、硅、镉6种元素。并研究了基体对6种被测元素以及被测元素间的干扰。进行了酸度与内标用量试验,以及精密度、准确度、回收率试验,获得了满意的结果。     

石墨炉原子吸收法测定岩石和土样中的锑

本文用石墨炉原子吸收法对岩石土样中Ｓｂ的测定方法进行了研究。对工作条件、测定酸度、涂层管，共存离子的干扰与消除、回收及精密度等进行了实验。采用Ｎｉ作为基体改进剂可以消除干扰元素对Ｓｂ的影响。此方法的回收率和精密度比较满意。     

火焰原子吸收法连续测定氧化锑中铅、铜、铁含量

确立了火焰原子吸收测定氧化锑中铅、铜、铁含量的方法,探讨了样品的前处理、酸度、及共存元素的干扰情况,确定了各元素测定的最佳条件,回收率在95.4％-112.1％之间,精密度RSD%不大于5.9％,该方法能满足氧化锑中铅、铜、铁元素的测定。     

原子吸收光谱法测定高纯稀土氧化铽中钙的干扰效应和分析条件的优选

本文用正交试验设计对高纯稀土氧化铽中钙测定时，对基体和酸度的干扰进行了试验。结果表明，基体和酸度的干扰表现为与分析元素无关。此外，仪器工作条件的改变．可产生不同程度的干扰。     

ICP-AES测定电解镍中的杂质元素

采用电感耦合等离子体发射原子发射光谱法(ICP-AES)测定了电解镍中锰、磷、钴、铁、铜、镁、铝、锌、镉、硅和锡等11种元素的含量,对仪器各项参数进行优化,采用基体匹配办法克服基体干扰,通过选择合适的分析谱线和背景校正消除共存元素间干扰。方法应用于实际样品分析,11种元素的回收率为92.0%—107.0%,相对标准偏差0.3%—5.1%,测定结果与标准方法的测定值相符。     

石墨炉原子吸收光谱法测定钛铁矿中钪

本文研究了石墨炉原子吸收光谱法测定钪时石墨管类型及共存元素的影响;并对干扰的消除方法进行了研究。以镧作为基体改进剂消除了大量铝、钛、铁、钙、镁的干扰。建立了测定钛铁矿中微量钪的分析方法,方法特征量为6.8×10~(-3)纳克,线性浓度范围为0-100纳克/毫升Sc_2O_3。该法简便、快速,准确度及精密度好。     

六氟硅酸铵后处理对H-ZSM-5分子筛酸性影响的固体NMR研究

本文利用固体核磁共振（NMR）实验对六氟硅酸铵（AHFS）溶液洗涤前后H-ZSM-5分子筛上铝物种变化引起的酸性改变进行了研究.结果显示经AHFS洗涤处理后，分子筛上构成Brøsted酸的骨架四配位铝物种会部分减少；具有Lewis酸性的骨架三配位铝量在经AHFS脱铝处理后少量降低；同时AHFS温和脱铝的方式主要会引起分子筛上另一类具有Lewis酸性且含Al-OH的铝物种大量减少，从而导致处理后分子筛整体酸性的显著改变.     

NMR研究超稳Y分子筛水热老化过程中结构与酸性的变化

利用固体核磁共振（NMR）结合探针分子技术,探讨了超稳Y分子筛在水热老化过程中酸中心结构和酸性的变化规律.结果表明,水热老化初期,大量的骨架铝脱出最终形成了非骨架五配位铝,使得丙酮探测到的Brønsted酸（B酸）酸量随着老化时间的增加而减少.而非骨架五配位铝会向表面迁移并形成多聚铝,使得分子筛中Lewis酸（L酸）酸量也随老化时间的增加而减少.在老化过程的前3 h内,酸量的变化幅度较大.整体硅/铝原子比相等的分子筛,其B酸酸量的变化幅度与新鲜剂的晶胞大小呈正比;随着老化时间的继续增加,不同配位的铝物种的含量趋于稳定,B酸和L酸的酸量变化幅度很小.在整个水热老化过程中,超稳Y分子筛中B酸和L酸的协同效应一直存在,由协同效应产生的一种酸性增强的B酸位的稳定性最好.     

Crystallinity and magnetic properties of electrodeposited Co nanowires in porous alumina

Crystalline Co nanowires were pulse electrodeposited into nanoporous aluminum oxide template having an ultra-thinned barrier layer. The effects of off-time between pulses and electrolyte acidity on the microstructure and magnetic properties of the nanowires were investigated. Increasing the off time between pulses increased the crystallinity and the alignment of easy axis with the wire axis. The rate of these increments was seen to depend on the electrolyte acidity and reached its maximum at pH=5.25 electrolyte acidity. Optimizing the crystallinity and crystal orientation, a coercivity value of 3320 Oe and a squareness of>90% were obtained for pure Co nanowires. A 10% increase in coercivity was found after annealing the samples.     

Assessment of surface acidity in mesoporous materials containing aluminum and titanium

The surface acidity of mesoporous molecular sieves of aluminum and titanium was evaluated using four different techniques: n-butylamine volumetry, cyclohexylamine thermodesorption, temperature-programmed desorption of ammonia and adsorption of pyridine. The nature, strength and concentration of the acid sites were determined and correlated to the results of a probe reaction of anthracene oxidation to 9,10-anthraquinone (in liquid phase). In general, the surface acidity was highly influenced by the nature, location and coordination of the metal species (Al and Ti) in the mesoporous samples. Moderate to strong Brönsted acid sites were identified for the Al-MCM-41 sample in a large temperature range. For mesoporous materials containing Ti, the acidity was represented by a combination of weak to moderate Brönsted and Lewis acid sites. The Ti-HMS sample exhibits a higher acidity of moderate strength together with a well-balanced concentration of Brönsted and Lewis acid sites, which enhanced both conversion and selectivity in the oxidation reaction of anthracene.     

Key factor affecting the structural and textural properties of ZSM-5/MCM-41 composite

ZSM-5/MCM-41 micro/mesoporous composite materials were synthesized by the hydrothermal technique with alkali-treated ZSM-5 zeolite as source of silica and aluminum and characterized by various physico-chemical techniques such as X-ray diffraction (XRD), nitrogen sorption at 77 K, transmission electronic microscopy (TEM), FTIR spectroscopy and NH₃ temperature programmed desorption (TPD) techniques. The effect of concentration of CTAB in the synthesis of these solids has been investigated, the mesopore volume, surface area and surface acidity decrease with increasing the concentration of CTAB. Increasing the CTAB concentration causes the recrystallization of zeolite ZSM-5 and it disadvantage the formation of mesoporous materials MCM-41. The catalytic activity of ZSM-5/MCM-41 materials has been evaluated in the Friedel–Crafts acylation of anisole with benzoyl chloride as alkylating agent. The results revealed the reaction to be influenced by surface area, pore volume and surface acidity.     

分子筛酸中心与NMR

通过沸石分子筛的固体高分辨核磁共振观测,可以确定骨架硅、铝比,分析硅、铝在骨架上的统计分布特征。基于化学位移或核电四极作用的表征,可识别、分辨铝在沸石中不同结构状态或配位状态;这些微观信息,有助于认识沸石酸性机理,以及对有关其合成、改性的种种研究提供重要依据。     

ICP-AES在锌合金分析中的应用

研究了ICP-AES同时测定锌合金中Al、Pb、Fe、Cd、Cu、Sn的分析方法.考察了基体及酸度对以上6种元素分析线强度的影响,并采用基体匹配、背景扣除及内标法等进行校正.     

Surface properties of mesoporous catalytic supports

The influence of the processing parameters on the properties of zirconia, alumina and silica MCM-41 has been investigated. Digestion of the precursors leads to zirconia, alumina and silica MCM-41 with higher surface area and better thermal stability. The effects of digestion are attributed to increased dehydroxylation, strengthening of the network between primary particles, and to a decrease in the number of surface defects. In the case of zirconia and alumina, digestion also increased the surface acidity. This may be due to the smaller crystallites which expose low-coordinated sites at the surface. Al-MCM-41 prepared by post-synthesis grafting of aluminum is compared with MCM-41 prepared by direct incorporation of aluminum during synthesis. The surface Si/Al ratio was determined using XPS and correlated to the catalytic activity of the Al-MCM-41 for the synthesis of jasminaldehyde.     

序贯试验法激光诱导击穿光谱实验条件优化

采用波长为1064 nm的Nd:YAG脉冲激光作为光源聚焦于铝合金表面产生激光诱导等离子体,使用三光栅光谱仪和门宽控制的ICCD检测光谱信号。实验分析了实验参数对Al Ⅰ 394.40 nm和Al Ⅰ 396.15 nm两条特征谱线强度和信背比的影响。研究表明,ICCD探测延时、ICCD门宽和激光脉冲能量对光谱信号和信背比有较大的影响,其中ICCD门宽变化会引起光谱信号信背比起伏变化。通过优化这些实验参数,确定了最佳实验条件,在低激光脉冲能量下获得了高光谱强度和信背比的信号,为定性和定量分析铝合金成分提供了有利条件。