ICP-AES法测定钛基合金中Cu、Ni和Zr的含量

建立了ICP-AES法测定钛基合金中高含量Cu、Ni和Zr的方法.通过优化试验,确定了仪器的最佳测量条件.研究了样品溶解方法,酸度,内标元素及其用量,基体及共存元素对测定的影响.该方法快速、准确,相对标准偏差RSD<2%,回收率为99%～101%,可以满足钛基合金的测定要求.     

离子选择性电极测定球形氢氧化镍中的硝酸根

合适浓度的氢氧化钠溶液浸取,使试样中的硝酸根与基体镍分离,以磷酸二氢钠为离子强度调节剂,离子选择性电极测定球状氢氧化镍中的硝酸根,浸出液中微量元素对测定无干扰.本法测定回收率96.5％～102.0％,标准偏差不大于0.0005％,相对标准偏差不大于7.27％.     

密闭消解电感耦合等离子体质谱法测定铝土矿中锂、锶、镓、铌、钽、锆和铪

采用电感耦合等离子体质谱,硝酸-氢氟酸增压密闭消解样品,实现了铝土矿中锂、锶、镓、铌、钽、锆和铪的同时测定。实验中探讨了最佳的消解程序,选择适当的同位素,并用铑、铼做内标元素,有效地抑制了分析信号的漂移。各元素的检出限在0.02～1.00μg.g-1,相对标准偏差在0.63%～1.63%,Nb,Ta,Hf的回收率在99.2%～99.6%;该方法经国家标准物质（GBW07177,GBW07182,GBW07180）验证,各元素测试结果与真值很接近。     

离子流强度累计法测定锂同位素丰度

本文介绍了离子流强度累计测定同位素比的方法。用热表面离子源测定了锂同位素丰度,在样品全耗尽过程中累计离子流强度。用该方法,同位素分馏效应对丰度比测量结果几乎没有影响。文中比较了累计法与常规法测量锂同位素丰度时分馏效应的差异。     

ICP-AES法测定锂离子电极材料钛酸锂中常量和微量元素

提出电感耦合等离子发射光谱法(ICP-AES)测定钛酸锂中Li,Ti,Al,Ba,Co,Fe,Mg,Zn等多种常量和微量组分的分析方法。研究试样处理方法,样品采用盐酸和氢氟酸室温处理后,再用硼酸络合过量的氟离子。采用优化的仪器工作条件,选择各元素合适的分析线,采用内标法消除干扰,选择钇作为内标元素,方法回收率为90.0%-106.2%,相对标准偏差为0.62%-3.49%,方法操作简便、快速、准确。     

铝锂合金预腐蚀疲劳退化研究

铝锂合金是一种新型的航空用铝合金。本文基于电化学原则建立了某地的腐蚀加速环境谱,并基于加速环境谱,研究了铝锂合金预腐蚀疲劳性能。研究结果表明,低腐蚀损伤对其疲劳寿命影响不大,而高腐蚀损伤会明显缩短试件的疲劳寿命。     

高分辨等离子体质谱法测定锂同位素丰度的方法研究

在核燃料中,锂同位素丰度是重要的检测对象。近十多年来,快速发展起来的ICP-MS技术具有分析速度快,成本低,灵敏度高等优点,已应用核材料中铀、铅等同位素测定。本文研究了高分辨等离子体质谱(HR-ICP-MS)测定锂同位素丰度的技术方法,测定了纯锂化合物中锂同位素丰度。     

电感耦合等离子体原子发射光谱法测定高温合金中贵金属元素

介绍了采用电感耦合等离子体原子发射光谱法( ICP- AES)测定高温合金中贵金属元素Pt、Pd、Ir、Ru、Rh和Au的方法,试样采用盐酸、硝酸溶解,进行了仪器工作参数和待测元素分析线的选择试验,确定了仪器最佳工作条件,考察了合金基体和共存元素对待测元素的影响,确定的各待测元素分析线分别为Pt 265.945nm、Pd 340.458 nm、Ir 224.268 nm、Ru 240.272 nm、Rh 343.489nm、Au 242.795 nm.通过基体匹配消除基体的影响,实现了用电感耦合等离子体原子发射光谱法测定高温合金中贵金属元素Pt、Pd、Ir、Ru、Rh和Au的含量.进行了加入回收试验,回收率在84～112％之间,方法的检出限是0.003～0.01μg/mL,相对标准偏差小于8％.     

脉冲增压毛细管分离富集ID-ICP-MS测定地质样品中微量锂的方法研究

采用一种脉冲增压毛细管柱 ,用于锂的分离富集。其原理类似于高效液相色谱 ,但使用钢瓶气为动力脉冲驱动液相在固定相中流动。使用粒度很细的固定相材料 ,惰性气体和液相脉冲交替通过固定相 ,使固定相的死体积减小到最低程度 ,从而获得很高的分离富集系数。试验了一种无机固定相材料和树脂材料用于锂的分离富集。结果表明 :无机材料能高效富集锂 ,但选择性较差、本底杂质较多 ;阳离子交换树脂分离效果好、本底低 ,能从镁、钙等大多数离子中很好地将锂分离 ,几乎没有拖尾现象 ,回收率达到 97% ,分离纯度高。分离后 ,用 ICP-MS测定锂同位素的比值 ,具有较高的测量精密度。用同位素稀释电感耦合等离子体质谱( ID-ICP-MS)测定地质样品中微量锂 ,结果相对标准偏差 sr<3%。方法检出限低 ,精密度高 ,分析速度快 ,是测定锂的较理想方法。     

火焰原子吸收法测定氧化铝中的杂质

本文采用压力溶样方法进行样品溶解,用火焰原子吸收法进行氧化铝中的Fe,Cu,Zn,Mn,Mg和K6种杂质元素的测定。对基体及共存离子的干扰及消除情况进行了研究,用标准加入回收法验证了方法的准确性,回收率为95％～104％;用精密度实验验证了方法的可靠性,相对标准偏差为:1.47％～2.98％。     

Rheological properties of lithium,lithium complex,and sodium greases

The rheological properties of two lithium, two lithium complex, and two sodium greases, all with the most common NLGI grade two, have been investigated. The greases are based on a mineral and a synthetic oil. The apparatus used was a cone-and-plate rheometer and an impacting-ball apparatus. The impacting-ball apparatus used a steel ball, which impacted a lubricated sintered carbide plate, to measure the shear stress-pressure coefficient, γ, of the lubricant. At pressures found in elastohydrodynamic contacts this coefficient determined the limiting shear stress. The γ-value thus affects the coefficient of friction and consequently, lower γ-value means less friction. The results from the impacting-ball apparatus showed that the γ-value was lower for the greases with a synthetic base oil and that the lithium greases gave a lower γ-value than the corresponding base oils. Results from the cone-and-plate rheometer showed the characteristic shear thinning behaviour of the greases and the influence of shear history and temperature. The results from the cone-and-plate rheometer have also been fitted to a four parameter rheological model.     

Measuring the lithium layer thickness

An epithermal neutron source based on a compact tandem accelerator is being built at the Budker Institute of Nuclear Physics for use in neutron capture therapy at a cancer clinic. It is expected that a lithium neutron-generating target will act as a neutron source. An original technique for determining the thickness of the lithium layer is proposed, and the measured radial distribution of the evaporated lithium layer thickness is presented.     

Strengthened lithium for x-ray blast windows

Lithium's high x-ray transparency makes it an attractive material for windows intended to protect soft x-ray diagnostics in high energy density experiments. Pure lithium is soft and weak, but lithium mixed with lithium hydride powder becomes harder and stronger, in principle without any additional x-ray absorption. A comparison with the standard material for x-ray windows, beryllium, suggests that lithium or lithium strengthened by lithium hydride may well be an excellent option for such windows.     

Thermorheological behaviour of a lithium lubricating grease

Thermal-induced changes in the viscous and viscoelastic responses of lubricating greases have been investigated through different rheological techniques in a temperature range of 0–175 °C. Small-amplitude oscillatory shear and viscous flow measurements were carried out on a model conventional lithium lubricating grease prepared by inducing the in situ saponification reaction between 12-hydroxystearic acid and hydrated lithium hydroxide. The linear viscoelasticity functions dramatically decrease above 110 °C, but not below this critical temperature, which determines the maximum recommended operating temperature in relation to its durability and resistance under working conditions. Two different regions, below and above this critical temperature, in the plateau modulus versus temperature plot have been detected. From this thermal dependence, a much larger thermal susceptibility of the lubricating grease at temperatures above 110 °C is apparent. The thermo-mechanical reversibility of this material has been studied by applying different combined stress–temperature protocols. Regarding the viscous flow, a minimum in the shear stress versus shear rate plots appeared at temperatures above 60 °C, more pronounced as temperature increases, resulting from material instabilities. The experimental results obtained have been explained on the basis of the thermo-mechanical degradation of the lubricating grease microstructure.     

High-resolution electron microscopy of disordered lithium ferrites

The disordered phase of lithium ferrite (α-LiFeO₂) shows characteristic circular short-range order (SRO) diffuse scattering around the 110 and the equivalent reciprocal lattice points in the diffraction pattern with the [001] incidence. The origin of the diffuse scattering has been explained by the SRO arrangement of lithium and iron ions inside an octahedron as the unit of the sodium chloride derivative structure (cluster model). In the present study, the local structure of the specimen is directly observed by high-resolution electron microscopy and microdiffraction to clarify the origin of the SRO diffuse scattering. The results obtained from the micrographs show that the SRO state of the specimen consists of regular arrangements of iron-rich regions with total size of 1.5 to 2.0 nm in the [001] and [0$\text{1}$1] projections. It is confirmed from the optical diffraction patterns of the micrographs and the microdiffraction patterns that the arrangements, as the results by the projections, explain the loci in the 001 and 0$\text{1}$1 sections of the characteristic SRO diffuse scattering. These results show that a part of the origin of the SRO diffuse scattering arises from ordering in the regions larger than the octahedral unit.     

A rheological model for lithium lubricating grease

The rheological properties of a lithium lubricating grease were examined under various settings of shear rate, time and temperature with an emphasis on the thixotropy of grease. A HAAKE RV 20 rheometer was employed in the experiments, utilizing a cone and plate configuration. Precautions were taken when scheming and carrying out the test in order to eliminate the effects of slip at the wall, fracture and other forms of disturbance. Flow curves and thixotropic hysteresis loops were obtained. Based on the measurement results, a new rheological model involving a structural parameter has been proposed. The characteristics of the proposed model and its implication for lubrication analysis were discussed.     

Upgrade of the lithium beam diagnostic at JET

A 60 kV neutral Li beam is injected into the edge plasma of JET to measure the electron density. The beam observation system has been improved by replacing a Czerny-Turner spectrometer with a high-resolution transmission-grating spectrometer and a fast back-illuminated frame-transfer camera. The larger throughput of the spectrometer, the increased sensitivity, and the faster readout of the new camera allow inter-ELM (edge localized mode) measurements (frame rate of 100 Hz). The calibration of the setup, as well as an improved spectral fitting technique in the presence of carbon background radiation, is discussed in detail. The density calculation is based on a statistical analysis method. Results are presented for different plasma scenarios.     

电动汽车动力锂电池模型参数辨识

针对纯电动汽车上动力锂电池等效模型参数辨识的问题,以某纯电动汽车的由87个单体串联的84 Ah的镍钴锰三元锂电池组为研究对象,基于市区行驶的电池数据,选用了二阶RC电池等效模型,辨识了等效模型的参数。基于整体电池数据,选取出了8段在连续的12个(及12个以上)采样周期内相邻两个采样点的电流变化绝对值超过0.2 C的电池数据段,分别对初始开路电压最大和最小的单体进行了参数辨识。以最小二乘法对电流连续变化最长的一段电池数据段作为参数辨识的结果,并结合整体电池数据对辨识得的结果进行了参数的验证。研究结果表明,初始开路电压最大单体的绝对误差平均值为3.62%,初始开路电压最小单体的绝对误差平均值为3.24%,满足工程要求,可运用于工程实践中。     

Preparation of lithium specimens for transmission electron microscopy

A method of preparing undeformed thin lithium specimens for TEM is described. A solution of dehydrated methanol and toluene is used both for initial dishing of the foil by chemical polishing and also for final thinning. Under electron beam irradiation in the TEM, new pure Li crystals can grow out of the existing Li specimen. These in situ crystals can be used for the study of the microstructure and electronic structure of Li using TEM and electron energy loss spectrometry.