非金属矿二级标样配制及其粉末样品的XRF分析方法

针对X射线荧光光谱法(XRF)压片法分析中非金属矿标样不能满足实际工作需要的情况,以四川峨边五渡钾长石矿为例,研究了如何根据非金属矿一级标样配制系列二级标样,以及如何根据二级标样对非金属矿粉末样品进行XRF压片法分析的方法。在采用X射线衍射分析(XRD)和化学分析法研究钾长石矿和一级标样矿物岩石学特征基础上,根据二级标样与待测样品的矿物岩石学特征相同相似原理,确定了非金属矿二级标样配制的基本方法和要求,即二者的矿物种类相同、矿物含量和化学成分相似,并适应待测样品成分的波动及矿物加工的需要,有利于XRF标准工作曲线的绘制;采用实验确定的非金属矿XRF压片法制样条件以及根据二级标样绘制的标准工作曲线,对钾长石矿的SiO2,Al2O3,Fe2O3,TiO2,MgO,CaO,K2O,Na2O等化学成分进行了XRF测试分析,其结果与化学分析法一致,说明本方法准确度较好,能够基本消除矿物效应的影响。     

X荧光光谱法分析硅质-半硅质耐火材料的主次元素含量

介绍了玻璃熔片XRF测定硅质-半硅质耐火材料中SiO2、Al2O3、Fe2O3、TiO2、CaO、MgO、K2O、Na2O等常见组分的定量分析。确定了该分析方法所适用的测定范围,并对标样的制备、试验条件的选择和分析结果做出了详细描述。     

XRF玻璃熔片法测定石英砂主次痕量组分

在硅砂、硅石标样中引入分析纯Fe2O3、TiO2、Cr2O3熔融制备标准样片,应用X射线荧光光谱法同时测定石英砂中SiO2、Al2O3、CaO、MgO、Na2O、K2O、Fe2O3、TiO2及Cr2O3,建立了石英砂成分校准曲线,解决了石英砂中痕量元素分析标准样品不足的问题.采用理论α系数和经验系数校正法克服了谱线重叠干扰和基体效应影响.用标准样品及未知矿物样品验证了方法的精密度和准确度,其结果与化学法的分析结果相符合.     

X射线荧光光谱法测定钒铁冶炼炉渣中的主要成分

利用X射线荧光光谱仪测定钒铁冶炼炉渣中的TV、Al2O3、CaO、MgO、Fe2O3、SiO2等主要化学成分的含量。采用自制标样绘制校准曲线,利用光谱干扰校正系数和基体效应校正系数消除光谱干扰和基体效应。试验结果表明:该方法简便快速、有良好的精密度和准确度,所得结果与湿法化学结果一致,能及时指导钒铁冶炼生产。     

波长色散X射线荧光光谱法测定长石主次量组分

采用高温熔融制样,X射线荧光光谱法同时测定长石中的SiO2、Al2O3、CaO、MgO、Na2O、K2O、Fe2O3、TiO2、Cr2O3等主次量元素.通过选用长石、叶腊石、高岭土及土壤等标准样品,并在标样中引入分析纯TiO2、Cr2O3,解决了长石成分分析标准样品不足的问题.采用理论α系数和经验系数校正法克服了谱线重叠干扰和基体效应影响.测定长石各组分的相对标准偏差(RSD,n=10)均小于5％,方法检出限为1.21-97.33μg/g,测定值与化学分析法结果吻合.     

ICP—AES法测定U3O8标样中Al、Cr、Fe、Mg、P、Pb、Ti、V、W

用7402季铵－Kel-F粉萃取色层使铀和待测杂质元素分离，接着用975型ICP光量计测定U3O8标样中Al、Cr、Fe、Mg、P、Pb、Ti、V、W，回收率为95－110％，相对标准偏差≤5％。     

粉末压片-X射线荧光光谱法测定钒渣中的化学成分

采用试样粉末直接压片,基体效应用仪器软件方法校正,谱线重叠干扰以本文提出的"干扰增量法"测量与计算出重叠校正系数K,输入仪器自动校正.用X射线荧光光谱法测定了钒渣中V2O5,SiO2,Al2O3,CaO,MgO,MnO,TiO2,Cr2O3,S,P含量.该方法测定钒渣标样的结果与认可值符合良好,试样9次压片测定各成分的相对标准偏差在0.09%-0.64%范围内.     

XRF聚酯薄膜-薄纸法测定铀铌合金的铌量

选用U3O8(纯度99．9％)和Nb(纯度99．96％)做基准物质，HF HCl溶解基准物质，配制七个铌含量为1％～8％的U-Nb标准溶液(每个样品中U Nb,总量15～20mg)，将其加热、浓缩至约0．5mL，分别滴加于粘贴在聚脂薄膜上的餐巾薄纸(φ20)上，置于红外灯下缓慢烘干，待测。将制备完毕的聚脂薄膜-薄纸标样平整地放于能量色散X射线荧光分析仪的样品盘上，测得各聚脂薄膜-薄纸标样中ULα和NbKα能峰的净强度。采用最小二乘法对标样中铌、铀的含量比与相应的特征X射线强度比进行线性拟合，     

傅里叶变换近红外光谱信息资源共享的基础研究

为了实现农产品傅里叶变换近红外光谱库信息资源的共享 ,使光谱库的信息资源达到充分利用 ,首先研究了仪器间光谱信息的准确表达 ,即仪器到仪器光谱信息间的映射 ;并以映射光谱研究了用于不同仪器上进行定量分析的无标样建模方法。对于 2 2个小麦样品蛋白质含量 ,无标样建模模型预测值与凯氏定氮结果的相关系数r =0 94 1,平均相对误差为 3 2 8% ;为了考察无标样建模模型定量分析的使用性 ,同时亦对 2 2个小麦样品的蛋白质含量采用有标样建模定量分析 ,模型预测值与凯氏定氮结果的相关系数r =0 96 3,平均相对误差为 2 4 %。有标样建模与无标样建模的模型分析结果的比较 ,为不同仪器间光谱信息的可共享性提供了依据。由此根据不同仪器建立的光谱信息库的库信息即可转化为另一仪器的映射光谱信息 ,保证了光谱库信息资源在不同仪器上的共享利用     

加氢催化剂中稀土及钼、钴含量的X-射线荧光光谱测定方法的研究

使用X 射线荧光光谱仪 ,采用人工合成标样 ,粉末直接压片和经验系数校正基体效应的方法 ,建立了加氢催化剂中稀土氧化物及氧化钼、氧化钴含量的测定方法。研究了制样方法、光谱条件 ,讨论了元素间的相互影响。测定范围MoO3:7%～ 13% ,CoO :2 %～ 7% ,RE2 O3:3%～ 6 %。该方法不仅快速、简便 ,而且准确度和精密度较好 ,在上述范围内 ,测定各元素的RSD均小于 2 %。此方法已用于大量样品的分析 ,测定结果与其他方法相符。     

交换纤维柱分离ICP-AES测定高纯氧化镱中La、Nd、Eu和Gd

以强酸型离子交换纤维柱分离富集高纯Yb₂O₃中La,Nd,Eu和Gd等痕量杂质元素,并用Optima 5300 DV ICP-AES测定分离富集后的这4种元素。供试纤维对Yb的动态吸附容量为134 mg·g-1,4.0 g纤维柱的分离条件为：pH 3.00的试液以1.0 mL·min-1流速上柱后,分离柱先以流速为1.5 mL·min-1的pH 3.00 HNO₃溶液80 mL预淋洗,再以同样流速pH 5.00的0.01 mol·L-1 EDTA铵溶液淋洗。结果表明：10 mg Yb与各为0.100 μg的La,Nd,Eu和Gd能达到基线分离;分离含100 mg Yb的试液后,在杂质富集液中Yb的残留浓度仅为0.017 1 μg·mL-1。 研究显示,当待测试液中Yb₂O₃的浓度小于100 μg·mL-1(如Yb 87.8 μg·mL-1)时,它对测定La,Nd,Eu和Gd等杂质元素的基体干扰可以忽略不计。富集倍数分别为La₂O₃ 3.68×105,Nd₂O₃ 4.20×105,Eu₂O₃ 3.82×105,Gd₂O₃ 4.01×105。方法检出限分别为La₂O₃ 0.005 0 pg·mL-1,Nd₂O₃ 0.014 pg·mL-1,Eu₂O₃ 0.001 8 pg·mL-1,Gd₂O₃ 0.008 2 pg·mL-1。本方法已用于99.99% Yb₂O₃样品中4种稀土杂质的测定,标准加入的平均回收率分别为La₂O₃ 94.2%,Nd₂O₃ 107%,Eu₂O₃ 97.8%,Gd₂O₃ 102%,RSD (%, n=5)分别为La₂O₃ 6.2,Nd₂O₃ 5.9,Eu₂O₃ 7.3,Gd₂O₃ 2.5,校正曲线不需进行Yb的基体匹配,分析周期为4 h。     

氧化物纳米材料Y2O3:(Yb3+,Er3+)上转换发光性质的研究

以Y2O3,Yb2O3,Er2O3为原料,利用燃烧法分别制备了Y2O3:Er3 和Y2O3:(Yb3 ,Er3 )两种纳米材料和相应的体材料Y2O3:(Yb3 ,Er3 ).用发射波长为978 nm的半导体激光器和日立F-4500荧光分析仪测量了它们的上转换发光,得到纳米材料Y2O3:Er3 的上转换发光主要为绿色上转换发射而纳米材料Y2O3:(Yb3 ,Er3 )主要为红色上转换发射,而后者与激活离子掺杂浓度相同的体材料Y2O3:(Yb3 ,Er3 )的上转换发射相比较,体材料以绿色上转换发射为主、红色上转换发射很弱.     

C_(60)O_n(n=2,3)异构体的合成和理论计算研究

本文通过臭氧氧化C60得到C60On的混合物,反相高压液相色谱图表明有两种C60O2异构体和两种C60O3异构体,分别标记为C60O2(I)、C60O2(II)和C60O3(I)、C60O3(II),同时得到了它们的UV-vis谱图。为了确定它们的最可能结构,我们对四种最可能的C60O2异构体和九种最可能的C60O3异构体进行了理论计算,从能量、偶极矩、电子光谱方面进行了系统研究,提出了实验得到的C60On(n=2,3)的稳定结构。计算结果与实验吻合良好。     

Influences of different oxidants on characteristics of La_2O_3/Al_2O_3 nanolaminates deposited by atomic layer deposition

A comparative study of two kinds of oxidants(H_2O and O_3) with the combination of two metal precursors(TMA and La(~iPrCp)_3) for atomic layer deposition(ALD) La_2O_3/Al_2O_3 nanolaminates is carried out. The effects of different oxidants on the physical properties and electrical characteristics of La_2O_3/Al_2O_3 nanolaminates are studied. Initial testing results indicate that La_2O_3/Al_2O_3 nanolaminates could avoid moisture absorption in the air after thermal annealing. However, moisture absorption occurs in H_2O-based La_2O_3/Al_2O_3 nanolaminates due to the residue hydroxyl/hydrogen groups during annealing. As a result, roughness enhancement, band offset variation, low dielectric constant and poor electrical characteristics are measured because the properties of H_2O-based La_2O_3/Al_2O_3 nanolaminates are deteriorated. Addition thermal annealing effects on the properties of O_3-based La_2O_3/Al_2O_3 nanolaminates indicate that O_3 is a more appropriate oxidant to deposit La_2O_3/Al_2O_3 nanolaminates for electron devices application.     

Synthesis of free-standing Ga_2O_3 films for flexible devices by water etching of Sr_3Al_2O_6 sacrificial layers

Flexible electronic devices have attracted much attention due to their practical and commercial value. Integration of thin films with soft substrate is an effective way to fabricate flexible electronic devices. Ga_2O_3 thin films deposited directly on soft substrates would be amorphous mostly. However, the thickness of the thin film obtained by mechanical exfoliation method is difficult to control and the edge of the film is fragile and easy to be damaged. In this work, we fabricated free-standing Ga_2O_3 thin films using the water-soluble perovskite Sr_3Al_2O_6 as a sacrificial buffer layer. The obtained Ga_2O_3 thin films were polycrystalline. The thickness and dimension of the films were controllable. A flexible Ga_2O_3solar-blind UV photodetector was fabricated by transferring the free-standing Ga_2O_3 film on a flexible polyethylene terephthalate substrate. The results displayed that the photoelectric performances of the flexible Ga_2O_3 photodetector were not sensitive to bending of the device. The free-standing Ga_2O_3 thin films synthesized through the method described here can be transferred to any substrates or integrated with other thin films to fabricate electronic devices.     

γ-Al_2O_3高温相变的激光Raman光谱研究

通过不同波长的Raman激发光对γ-Al2O3的高温相变过程进行了研究。发现用632.8 nm激发光测得的位于1175、1241cm-1和1370、1400cm-1,对应于514.5 nm激发光时位于4808、4875cm-1和5003、5033cm-1的谱峰均是Al2O3中杂质的荧光光谱。较低波数的二个谱峰与θ-Al2O3有关,而较高波数的二个谱峰与α-Al2O3有关。随着焙烧温度升高,从800℃开始γ-Al2O3逐渐向θ-Al2O3和α-Al2O3转变,θ-Al2O3的谱峰强度在1100~1200℃焙烧时最大,当温度继续升高到1250℃全部转变成α-Al2O3,并且Al2O3的相变是从表层开始的。     

B_2O_3—Al_2O_3—PbO玻璃组成和物化性质的研究

本文研究了在B_2O_3—Al_2O_3—PbO玻璃中引入SiO_2、Sb_2O_3、Ga_2O_3后,TF光学玻璃化学稳定性及相对部分色散P_(g·F)。论证了B_2O_3—Al_2O_3—PbO光学玻璃光学性质、化学组成和结构关系。TF光学玻璃在3.51铂坩埚熔制。     

Magnetic field aligned orderly arrangement of Fe_3O_4 nanoparticles in CS/PVA/Fe_3O_4 membranes

The CS/PVA/Fe_3O_4 nanocomposite membranes with chainlike arrangement of Fe_3O_4 nanoparticles are prepared by a magnetic-field-assisted solution casting method. The aim of this work is to investigate the relationship between the microstructure of the magnetic anisotropic CS/PVA/Fe_3O_4 membrane and the evolved macroscopic physicochemical property. With the same doping content, the relative crystallinity of CS/PVA/Fe_3O_4-M is lower than that of CS/PVA/Fe_3O_4.The Fourier transform infrared spectroscopy(FT-TR) measurements indicate that there is no chemical bonding between polymer molecule and Fe_3O_4 nanoparticle. The Fe_3O_4 nanoparticles in CS/PVA/Fe_3O_4 and CS/PVA/Fe_3O_4-M are wrapped by the chains of CS/PVA, which is also confirmed by scanning electron microscopy(SEM) and x-ray diffraction(XRD)analysis. The saturation magnetization value of CS/PVA/Fe_3O_4-M obviously increases compared with that of non-magnetic aligned membrane, meanwhile the transmittance decreases in the UV-visible region. The o-Ps lifetime distribution provides information about the free-volume nanoholes present in the amorphous region. It is suggested that the microstructure of CS/PVA/Fe_3O_4 membrane can be modified in its curing process under a magnetic field, which could affect the magnetic properties and the transmittance of nanocomposite membrane. In brief, a full understanding of the relationship between the microstructure and the macroscopic property of CS/PVA/Fe_3O_4 nanocomposite plays a vital role in exploring and designing the novel multifunctional materials.     

高压高温下B2O3与Mg和Li3N的反应

 通过B₂O₃与Mg和Li₃N分别在不同温度压力条件下的反应，用X射线方法研究了生成物的物相。当采用Mg与B₂O₃为原料时，其产物是Mg₃B₂O₆；用Li₃N与B₂O₃反应时，产物中除了Li₃BO₃，还有立方氮化硼（cBN）生成。这表明，当原料中含有相同数量B₂O₃时，用Mg和Li₃N分别作触媒合成立方氮化硼，将得到不同的结果。     

A simulation study of field plate termination in Ga_2O_3 Schottky barrier diodes

In this work, the field plate termination is studied for Ga_2O_3 Schottky barrier diodes(SBDs) by simulation. The influence of field plate overlap, dielectric material and thickness on the termination electric field distribution are demonstrated.It is found that the optimal thickness increases with reverse bias increasing for all the three dielectrics of SiO_2, Al_2 O_3, and HfO_2. As the thickness increases, the maximum electric field intensity decreases in SiO_2 and Al_2O_3, but increases in HfO_2.Furthermore, it is found that SiO_2 and HfO_2 are suitable for the 600 V rate Ga_2O_3 SBD, and Al_2O_3 is suitable for both600 V and 1200 V rate Ga_2O_3 SBD. In addition, the comparison of Ga_2O_3 SBDs between the SiC and GaN counterpart reveals that for Ga_2O_3, the breakdown voltage bottleneck is the dielectric. While, for SiC and GaN, the bottleneck is mainly the semiconductor itself.