EXAFS STUDY OF THE LOCAL STRUCTURE NANOCRYSTALLINE FeZrB(Cu) SOFT MAGNETIC ALLOYS

The changes of local structures around Fe and Zr atoms in the nanocrystalline films of Fe₈₅Zr₉B₆ and Fe₈₄Zr₉B₆ Cu₁ alloys during annealing process were investigated by extended X-ray absorption fine structure (EXAFS) technique. It is confirmed that Zr atoms always exist in amorphous phase and do not dissolve in the bcc α-Fe crystalline phase. The addition of 1 at% Cu lowers the crystallization temperature.     

SOLID-STATE VARIABLE-TEMPERATURE NMR STUDY ON THE PHASE SEPARATION OF POLYETHER POLYURETHANE ZWITTERIONOMERS

Polyether-polyurethane zwitterionomers based on 4, 4'-diphenylmethane diisocyanate(MDI), methyl diethanolamine (MDEA), and polytetramethylene oxide glycol (PTMO) werestudied with variable-temperature wide-line ~1H NMR. It is found that upon ionization, degree ofphase separation in the polymer system decreased at first due to the loss of hard segmentregularity, while further ionization increased the degree of phase separation through increasinghard phase cohesion and difference of polarity between hard and soft segments.     

直接进样X射线荧光光谱法测定汽油中痕量锰和铁

将样品直接注入液体杯,用X射线荧光光谱法测定汽油中痕量锰和铁含量,锰、铁的检出限为0.2mg·L-1。采用康普顿散射线作内标,部分地校正了样品间的基体差异。     

数学模型的建立及其应用于聚丙烯树脂的近红外漫反射光谱分析

采用偏最小二乘(PLS)回归法,分别建立了近红外漫反射光谱法测定聚丙烯的正己烷提取物及熔体流动速率的数学模型,并选择了最佳光谱预处理方法、谱区范围及主因子数。正己烷提取物及熔体流动速率数学模型的决定系数(R2)分别为98.03%及96.65%、交叉验证均方差分别为0.0495及0.94。结果表明,预测值与标准法测定值较为接近,方法适用于大批量聚丙烯品质分析。     

A SOLID NMR STUDY OF POLYETHERESTER-UREAS

The morphology of some polyetherester-ureas were studied by ~(13)C CP/MAS and ~1H wide-line NMR spectroscopy. It was found that the HDI and MDI based polymers have well crystallized hard segments, whereas the TDI and HMDI based ones have not. For HDI/MDI based polymers, the presented results suggest that the distribution of two kinds of hard segment units is mainly in a block form. The influences of the different hard segment and chain length on the mobility of the soft segment were also studied.     

X射线荧光光谱法直接测定燃料油中铝、硅、硫、钒

提出了应用波长色散X射线荧光光谱法直接测定燃料油中铝、硅、硫及钒含量的方法,用理论α影响系数及内标法校正基体效应,试样预先在60℃及59 kHz超声水浴中搅拌45 min,达到有效地使样品均匀化.测得铝、硅、钒及硫4元素的检出限依次为1.0,0.9,0.7,0.6 mg·kg-1,对两个已知样品中4元素分别按所提出的方法测定7次,从而计算得方法的相对标准偏差在0.5%～12.6%范围内.对4个燃料油样品分别用此方法及标准方法作了分析,所测得4元素的含量互相吻合.     

气相色谱法测定用于食品包装的PVC保鲜膜中作为增塑剂加入的二-（2-乙基己基）己二酸酯

聚氯乙烯(PVC)保鲜膜与作为增塑荆加入的二-(2-乙基乙基)己二酸酯(DEHA)一起用环己酮溶解后于溶液中加入无水乙醇使PVC生成沉淀而与DEHA分离,将滤液用无水乙醇定容为100 mL供气相色谱测定.用HP-5毛细管柱(15 m×0.32 mm,0.25um)作为色谱柱,按预定程序从140℃升温至270℃(气化温度),并记录输出色谱信号.用色谱峰的保留时间进行定性分析,用标准曲线进行定量分析.方法的检出限(3S/N)为0.9 mg·L-1,测得方法的回收率在96.8%-101.4%之间,测得结果的相对标准偏差(n=5)为1.1%.     

氧弹燃烧-离子色谱法测定原油中氯和溴

采用氧弹燃烧法对原油样品进行燃烧,然后用碳酸钠-碳酸氢钠溶液作为吸收液进行吸收,并提出了离子色谱法分离测定原油中氯和溴的含量的方法。以Dionex IonPac AS23型分离柱为离子交换柱,以4.8mmol·L-1碳酸钠-1.0mmol·L-1碳酸氢钠溶液为淋洗液等度洗脱。氯和溴的质量浓度均在0.01～1mg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)分别为0.3mg·kg-1与0.7 mg·kg-1。方法用于原油样品分析,测定值的相对标准偏差(n=6)在3.5%～4.2%之间,回收率在91.8%～109%之间。     

超声萃取/气相色谱-质谱联用法对PVC制品中三(2-氯乙基)磷酸酯的快速测定

建立了PVC制品中三(2-氯乙基)磷酸酯(TCEP)的超声萃取/气相色谱-质谱联用快速测定分析方法.考察了萃取溶剂、萃取时间和水浴温度等因素对测定的影响.优化的超声萃取条件为以乙酸乙酯为萃取溶剂,萃取时间为60 min,水浴温度为40 ℃.在优化实验条件下,TCEP的质量浓度在0.1 ～10 mg/L范围内与峰面积呈良好的线性关系,相关系数为0.999 6,方法的定量下限(S/N=10)为0.1 mg/L,回收率为101% ～104%,相对标准偏差为0.76% ～3.5%.该方法具有线性范围宽、重复性好、准确度高、速度快等特点,可用于PVC制品中TCEP含量的测定.     

Bias phase and light power dependence of the random walk coefficient of fiber optic gyroscope

Taking account of shot noise, thermal noise, dark current noise, and intensity noise that come from broad band light source, the dependence of the random walk coefficient of fiber optic gyroscope (FOG) on bias phase and light power is studied theoretically and experimentally. It is shown that with different optical and electronic parameters, the optimal bias phase is different and should be adjusted accordingly to improve the FOG precision. By choosing appropriate bias phase, the random walk coefficient of the aim FOG is reduced from 0.0026 to 0.0019 deg./h~(1/2).