具有非惯量负载转矩补偿功能的伺服永磁同步电机控制方法

通过电机运动学方程建立以负载惯量、黏性阻尼系数、负载重力力矩和负载初始位置角度为需辨识参数的拟合模型函数式,通过基于该模型函数的非线性回归方法拟合得到这四个参数,从而得到非惯量的负载转矩,使其前馈补偿经典电机PI控制方法中的电流环,实现对时变负载转矩的补偿。仿真结果验证了该方法能使速度响应较快跟踪输入的速度命令,避免较大速度误差的出现。     

基于3D打印技术的眼科OCT设备计量校准装置研制

为了评估眼科光学相干断层成像（OCT）设备的分辨率、视场角、图像匹配度、深度测量准确性等多个关键参数,确保设备输出量值的准确性与有效性,设计并研制了一种模拟真实人眼结构且参数可溯源的模拟眼,包含角膜和晶状体等人眼主要屈光结构。设计并依托3D打印技术加工了用于横向与轴向分辨率检测的三维分辨率板;设计加工了用于视场角检测的阶梯状同心圆环结构;同时设计加工了用于图像匹配度检测的交叉光纤组件和用于深度测量准确性参数检测的平行玻璃板组件,可适配于模拟眼眼底凹槽内。使用共焦拉曼显微镜对三维分辨率板尺寸溯源,横向和轴向最小可检测分辨率分别为9.7 μm和5.7 μm;使用尼康投影仪对同心圆环尺寸及光纤直径溯源,最大可检测视场角109.03°以及最小62.5 μm的图像匹配度检测;使用尼康高度计对平行玻璃板中心厚度溯源,其测量不确定度小于5 μm。经过对商用眼科OCT设备测试表明,结合微纳3D打印技术的计量校准用模拟眼具有精度高、集成度高、适用范围广、稳定性强等优点,适用于眼科OCT设备的计量校准。     

Validation of the sensitive and accurate quantitation of the fatty acid distribution in bovine milk

A method for the precise analysis of the complex mixture of fatty acids in milk has been developed and validated. The triacylglycerol of nonanoic acid was applied as the internal standard (ISTD) for absolute quantification. Milk lipids were extracted by miniaturised ultrasonication and methylated with trimethylsulfonium hydroxide. Resulting fatty acid methyl esters were determined by gas chromatography with flame ionisation detection giving excellent resolution, including separation of several 18:1 isomers. The low quantitation limit (0.01 mg mL⁻¹ milk) indicates that the sensitivity of the method is sufficient to quantify up to 50 fatty acids, from 4:0 to 23:0. Measurements of precision provided excellent results for different bovine milk samples of different fat content (coefficient of variance: 1.9% and 9.8% for intra- and interday precision, respectively). Recovery averaged 108 ± 3.5%. Evaluation of methods for determining the total fat content showed that gravimetry is no longer needed when using the ISTD.     

Thermal expansion behavior,microhardness and electrochemical corrosion resistance properties of Au52Cu27Ag17–x(NiZn0.5)x alloys

The thermal expansion behavior, microhardness and electrochemical corrosion resistance of Au₅₂Cu₂₇Ag_17–x(NiZn_0.5)_x (x=0, 6 and 12) alloys were investigated by dilatometer (DIL), microhardness tester, electrochemical workstation, X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). With increasing x, the relative length expansion and DIL maximum temperature T_{l m} (i.e., thermal stability) of the alloys increase in thermal expansion measurements, which can be explained by the change of the atomic binding energy, mismatch entropy together with phase transformation. With the increase of x, the microhardness can be improved, but the corrosion resistance decreases; in addition, the anodic peak current densities of polarization curves decrease, which are related closely with the solid solution degree and dissolution of Ag, Ni and Zn alloying elements in Cl⁻-containing solution.     

The effect of surface roughness on the vibration behavior of AFM piezoelectric MC in the vicinity of sample surface in air environment based on MCS theory

Recent developments in the field of piezoelectric materials have led to the increasing use of piezoelectric materials in a variety of Atomic Force Microscopy (AFM). Utilizing piezoelectric layer as a sensor and actuator not only reduces the size of microscope but also enhances the quality of surface topography in Micro and Nano scales. In the current study, the effect of surface roughnesson the vibration behavior of AFM piezoelectric micro cantilever (MC) has been investigated in Micro and Nano scales according to the types of the surface roughness. Furthermore, the micro cantilever modelling has been schemed based on the Modified Couple Stress (MCS) theoryin order to model the vibration amplitude of AFM piezoelectric MC that precisely indicates the measured surface roughness. Besides, according to the various modelling of surface roughness, the effect of roughness radius on the minimum and maximum amplitude of Piezoelectric MC has been studied based on the geometry of roughness in air environment. In this environment, the effect of environmental forces including van der Waals, Capillary and contact forces on the vibration amplitude of MC forms the basis of surface topography which has, also, been studied in this article. Moreover, the present study intends to investigate the effect of surface roughness on the vibrating amplitude of MC in both the Tapping and Non-Contact Modes.     

金基体多元素标准溶液的稳定性检验

为消除金溶液中基体的影响,配制了金基体多元素标准溶液,采用ICP-AES法对此标准溶液中Ag、Cd、Cr、Cu、Fe、Ni、Pb、Zn元素浓度进行稳定性测试,并利用线性拟合法进行数据分析。结果表明,金基体多元素标准溶液在12个月内浓度无显著性变化,证明溶液在避光和15~30℃环境下可以稳定贮存。     

三相电能表检定装置的扩展应用

近来来以16位单片为中央处理器的电参数测试仪的应用越来越广泛，其特点是数字化、测试功能多、量程范围宽、具有和计算机通讯的功能。但是计量部门原有的电三表检定装置不能满足其测试要求，我们在资金较为紧张的情况下，在三相电能表检定装置的基础上开发了一套控制程序，在它的控制下，用三相电能表检定装置来对电参数测试仪进行测试，较好地解决了这个问题。     

沉淀方式对纯银中As和Hg测定回收率的影响

采用不同沉淀剂(HCl和KSCN)分离银基体,研究沉淀方式对纯银中有害元素As和Hg的电感耦合等离子体发射光谱(ICP-AES)测定回收率的影响。结果表明,两种沉淀方式均不吸附As,但对Hg均有吸附,其原因是Hg与沉淀发生共沉淀;采用沉淀剂滴加-搅拌的方式,AgCl沉淀仍然吸附Hg,但可避免AgSCN对Hg的吸附;Hg测定加标回收率大于95%,相对标准偏差(RSD)小于5%,可满足杂质元素Hg测定要求。对吸附机理的探讨认为,由于AgCl沉淀密度较大、致密度高,与HgCl2可能形成共晶,因而难以通过慢沉淀-搅拌的方式消除对Hg的共沉淀吸附。     

电动汽车充电桩/机校验仪国内技术现状及溯源研究

电动汽车交流充电桩校验仪、电动汽车直流充电机校验仪是电动汽车充电桩/机的计量标准器,其准确可靠可为强检计量器具电动汽车充电桩/机的量值提供保证。通过对国内电动汽车充电桩/机校验仪的长期全面测试和理论研究,较全面掌握了电动汽车充电桩/机校验仪的生产水平和质量状态,在大量实际数据的支撑下,对最小电流、温度系数、失真度、纹波等进行了溯源研究,掌握了关键参数值和检测方法,为相关国家规程的编写打下坚实基础。     

全球定位系统（GPS）技术的发展现状及未来发展趋势

文章对当前GPS技术的发展现状和未来发展趋势进行了研究和探讨,首先指出了当前GPS技术发展的三个特点,然后对GPS技术的发展趋势进行了大胆的预测和展望,提出未来GPS技术发展的四大特点。