标准转速装置测量结果的不确定度评定

根据计量技术规范JJF1069-1999《测量不确定度评定与表示》的要求，对标准转速装王的测量结果进行不确定度评定。     

电能表的测量结果不确定度评定

应用《测量不确定度的评定与表示》(JJF 1059—1999)的测量不确定度评定的方法,结合电能表误差测量的具体特点,说明了对电能表的测量结果的不确定度的评定方法,特别对较难评定的B类评定进行了合理简化,从标准电能表引起的标准不确定度分量、由导线压降引起的标准不确定度分量、由修约估算的不确定度分量3个方面对B类影响进行了评定。     

0.01级三相电能表标准装置检定或校准结果的测量不确定度评定与验证

测量不确定度评定是误差理论的发展,完整的测量结果应包含测量不确定度.本文建立的0.01级三相电能表标准装置,做为省级电力系统最高等级的计量标准,对其检定或校准结果的测量不确定度进行合理评定,并通过两种方法进行了验证,从而充分反映了该计量标准的测量能力,以此体现实验室的整体水平.     

电能表标准装置测量结果不确定度评定

测量不确定度是表征合理地赋予被测量之值的分散性,与测量结果相联系的参数.为了指导在不同应用情况下,对电能表标准装置测量结果不确定度的评定,本文提出电能表标准装置申请建立计量标准时,从对装置解剖的角度评定测量结果的不确定度;对已通过计量标准考核的装置,将装置的等级作为与装置相关的属性进行不确定度评定.最后文中给出应用举例.     

继电器检验测量不确定度的研究

测量不确定度评定是实验室的一项很重要的工作.它是判断检验结果准确性、检验水平高低以及检测质量的一个重要依据.测量不确定度的评估程序应包括:A类标准不确定度uA、B类标准不确定度uB、合成不确定度uC和扩展不确定度U等量的评定.开展测量不确定度的评定,要对测量体系进行分析,找出各种影响测量结果的不确定度的来源,根据其影响因素确定上述各种参数的大小,最后完成测量不确定度的评估.继电器检验测量不确定度在国内还没有正式开展,通过对继电器检验测量不确定度研究,找出影响继电器检验质量的各种因素,提高检验水平,保证检验结果的准确性.     

转矩示值误差测量结果的不确定度评定

对转矩转速测量仪转矩示值测量结果的不确定度进行了评定,建立了不确定度评定的数学模型,分析了测量过程中的不确定度来源,并量化不确定度分量,从而求出合成不确定度和扩展不确定度。通过比较各分量的相对不确定度可以看出,由静校台力臂误差引入的不确定度分量较大,可以通过优化静校台力臂参数等途径来减小。     

锂离子电池材料中锌含量测定的不确定度分析

通过对火焰原子吸收光谱法测定锂离子电池材料中锌含量的不确定度的系统分析,阐述了测量结果不确定度组要来源于称量不确定度、体积不确定度、标准曲线拟合不确定度及测量重复性引入的不确定度,并对这些量进行了量化计算,最后评定了锌含量的合成标准不确定度和扩展不确定度.经过计算,得出影响锌含量测定不确定度的主要因素是标准曲线拟合引起的不确定度.     

电测量变送器测量结果的不确定度评定

根据变送器检定规程和测量不确定度评定技术规范的要求,对变送器测量结果的不确定度进行了详细的分析与评定,以功率变送器为例,阐述了变送器不确定度评定的方法和步骤,为计量检定机构建立变送器计量标准,全面而准确地进行测量结果的不确定度评定．提供有益的借鉴。     

离子色谱法测量发电厂水汽系统蒸汽钠离子的不确定度评定

为确保检测数据的准确性和可靠性,有必要对测定方法进行不确定度评定。根据测量不确定度评定方法,分析了离子色谱仪测量电厂水汽系统蒸汽钠离子的主要不确定度来源,明确了各不确定度分量的大小。评定结果表明：离子色谱仪测量电厂水汽系统蒸汽钠离子不确定度的主要来源由标准工作曲线拟合产生,而测量重复性、加标回收率及标准工作溶液的配制也是引入不确定度的因素。     

三相电能计量标准测量结果的不确定度评定与验证

文中运用数理统计和实验方法对三相电能计量标准测量结果的不确定度进行分析和计算,并以实例给出三相电能计量标准测量结果不确定度评定与验证的方法和步骤,评定结论给出了测量结果的可靠程度。测量不确定度能够全面说明电能计量标准测量能力的优劣,成为考核电能计量标准综合性能的重要依据。     

Y2O3/La2O3/Al2O3/Cu复合材料的制备与性能

采用含氧氮气(N2/O2)雾化喷射沉积技术制备Y-La-Al-Cu系多元系合金,通过化学反应原位生成(内氧化法)Y2O3/La2O3/Al2O3/Cu多相氧化物颗粒增强铜基复合材料,并对材料的显微组织、力学物理性能和电学性能进行研究。结果表明,通过喷射沉积技术并结合内氧化工艺,可制得具有较好微观组织、形成的增强相弥散分布于基体、组织致密的Y2O3/La2O3/Al2O3/Cu多相氧化颗粒增强铜基复合材料;随着冷加工变形量的增加,Y2O3/La2O3/Al2O3/Cu多相氧化颗粒增强铜基复合材料的抗拉强度和硬度提高,而材料的延伸率与导电率逐渐降低。     

High dielectric permittivity of SrBi2Nb2O9(SBN) added Bi2O3 and La2O3

In this paper, the structural and dielectric properties of SrBi₂Nb₂O₉ (SBN) as a function of Bi₂O₃ or La₂O₃ addition level in the radio (RF) and microwave frequencies were investigated. The SBN, were prepared by using a new procedure in the solid-state reaction method with the addition of 3; 5; 10 and 15 wt.% of Bi₂O₃ or La₂O_3. A single orthorhombic phase was formed after calcination at 900 °C for 2 h. The analysis by x-ray diffraction (XRD) using the Rietveld refinement confirmed the formation of single-phase compound with a crystal structure (a?=?5.5129 Å, b?=?5.5183 Å and c?=?25.0819 Å; α?=?β?=?γ?=?90°). Scanning Electron Microscope (SEM) micrograph of the material shows globular morphologies (nearly spherical) of grains throughout the surface of the samples. The Curie temperature found for the undoped sample was about 400 °C, with additions of Bi³⁺, the temperature decreases and with additions of La³⁺ the Curie temperature increased significantly above 450 °C. In the measurements of the dielectric properties of SBN at room temperature, one observe that at 10 MHz the highest values of permittivity was observed for SBN5LaP (5%La₂O₃) with values of 116,71 and the lower loss (0.0057) was obtained for SBN15LaP (15%La₂O₃). In the microwave frequency region, Bi₂O₃ added samples have shown higher dielectric permittivity than La₂O₃ added samples, we highlight the SBN15BiG (15 % Bi₂O₃) with the highest dielectric permittivity of 70.32 (3.4 GHz). The dielectric permittivity values are in the range of 28–71 and dielectric losses are of the order of 10^?2. The samples were investigated for possible applications in RF and microwave components.     

V2O5含量对Bi2O3-V2O5复合添加NiCuZn铁氧体性能的影响

用传统陶瓷工艺制配了(Ni0.16Cu0.2Zn0.64O)1.02(Fe2O3)0.98铁氧体材料,研究了Bi2O3-V2O5复合添加对材料烧结特性和磁性能的影响.结果表明,复合添加bi2O3-V2O5能促进样品致密化、提高起始磁导率和品质因数.当添加0.3wt%Bi2O3、0.15wt%V2O5时,930℃烧结起始磁导率μi＞800、品质因数(94)、密度(5.12 g/cm3)都达到较大值,比同样配方只掺杂Bi2O3的NiCuZn材料明显提高.     

CuO/g-Al2O3和CuO-CeO2-Na2O/g-Al2O3催化吸附剂的脱硝性能

利用改进的溶胶凝胶法制备纳米孔径的CuO/γ-Al2O3和CuO-CeO2-Na2O/γ-Al2O3催化吸附剂颗粒,在固定床上测试其催化脱硝活性。两类催化吸附剂250～400℃范围内脱硝效率稳定在70％以上。在350℃时效率稳定在最高值。利用程序升温方法研究了两类催化剂对NH3和NO的氧化性能,发现NH3在高于400℃下急剧氧化,是脱硝效率下降的主要原因。CuO/γ-Al2O3催化剂能将NO氧化生成NO2,NO2生成有利于脱硝反应的进行。NO在催化剂上的吸附对脱硝过程有重要作用。改进的CuO-CeO2-Na2O/γ-Al2O3催化剂能使NH3在高温400℃下不被氧化,也促进了NO在催化剂表面的吸附,从而提高催化剂了脱硝效率。催化剂反应的机理为NO吸附在催化剂表面,氧化生成吸附态的NO2,其再与吸附催化剂上的NH3反应。     

球形四氧化三锰合成锰酸锂的性能

分别以湿法沉淀的球形四氧化三锰(Mn3O4)和商业电解二氧化锰(EMD)为锰源合成锰酸锂(Li Mn2O4)。通过杂质含量分析、XRD、SEM和充放电测试等,研究锰源对产物性能的影响。以粒度为10μm的球形Mn3O4为原料合成的Li Mn2O4保留了锰源的物化特征,以1.0 C在3.00~4.35 V充放电,首次放电比容量为117.2 m Ah/g,常温、55℃高温循环100次的容量保持率分别为94.6%和91.0%,高于以EMD为原料合成的Li Mn2O4(分别为87.9%和72.9%)。循环性能的提高,与球形Li Mn2O4的粒度分布集中、比表面积小及杂质含量低有关。     

Effect of CoFe2O4 content on the dielectric and magnetoelectric properties in Pb(ZrTi)O3/CoFe2O4 composite

Ferroelectric Pb(Zr_0.53Zr_0.47)O₃ (PZT) and ferromagnetic CoFe₂O₄ (CFO) composite ceramics, [(1???x)PZT???xCFO for x?=?10, 20, 30, 40 and 50 wt.%], were prepared by a conventional solid-state reaction method. X-ray diffraction studies revealed that only PZT and CFO phases were present in the composite samples and no other phase was detected. The 0.9PZT-0.1CFO composite ceramic displayed better piezoelectric properties. The piezoelectric resonance frequency increased with the CFO content, but the resonance peak attenuated rapidly and disappeared when the CFO content equaled to 0.5. The permittivity peak temperature was the same as that of pure PZT ceramics. 0.9PZT-0.1CFO composite also had the highest magnetoelectric (ME) coupling coefficient among the studied PZT-CFO composite ceramics. The ME coefficient linearly increased with ac frequency up to 100 kHz.     

掺杂Bi2O3、Mn3O4、CO2O3、LiCO3对NiCuZn铁氧体材料性能的影响

为了提升叠层片式抗EMI滤波器用低温共烧NiCuZn铁氧体材料的性能,研究了Bi2O3、Mn3O4、Co2O3、LiCO3掺杂对NiCuZn铁氧体材料微观结构及电磁性能的影响。采用传统的氧化物法制备NiCuZn材料,对材料的主配方、助烧剂、掺杂进行适当的选择,采用适当制备工艺可达到良好效果,制备出优异性能的抗EMI滤波器用低温共烧NiCuZn铁氧体材料。     

Cr_2O_3修饰Li_4Ti_5O_(12)的制备及电化学性能

采用湿法球磨工艺和热处理制备三氧化二铬(Cr2O3)修饰钛酸锂(Li4Ti5O12)材料。Cr2O3修饰后,Li4Ti5O12的XRD图中没有出现杂质峰。Cr2O3修饰可提高Li4Ti5O12在高倍率下的容量保持率和循环性能。Li4Ti5O12-1.5%Cr2O3材料的倍率性能和循环性能最好,以5.0 C在1.0~2.5 V充放电,第500次循环的放电比容量为122.8 m Ah/g,容量保持率为96.2%;纯相Li4Ti5O12分别为48.3 m Ah/g、81.1%。Cr2O3修饰降低了Li4Ti5O12的电荷转移阻抗,提高了材料的电化学活性。     

杂相Mn2O3对尖晶石LiMn2O4容降的影响

用扫描电镜、X-射线衍射、等离子体原子发射光谱、热重分析、循环伏安、恒电流充放电、交流阻抗法研究作了比较.熔盐法制备的样品的了溶胶-凝胶法合成的尖晶石锂锰氧化物的物理化学性能,并与熔盐法合成样品颗粒为不规则块状,初始容量低（99.6 mAh/g）,而溶胶-凝胶法制备样品的颗粒细小、均匀,初始容量较高（112.5 mAh/g）.但是熔盐法制备的样品经30次循环后容降为15%,而溶胶-凝胶的却高达40%.熔盐法制备的样品中实际Li/Mn为0.506,与原料中Li/Mn摩尔比相近,而溶胶-凝胶法只有0.473,比原料中的小.熔盐法制备的样品为纯尖晶石结构,而溶胶-凝胶法制备的有杂相Mn2O3生成.热处理过程中部分Li的挥发损失和非电化学活性Mn2O3的生成导致锂锰氧化物容量快速下降.     

Crystallization kinetics and the dielectric properties of SrO-BaO-Nb2O5-B2O3 glass-ceramics

Glass-ceramics materials of SrO-BaO-Nb₂O₅-B₂O₃ system have been prepared by conventional melt-casting followed by controlled crystallization. The crystallization kinetics, phase evolution, microstructure, breakdown strength and dielectric properties have been explored by differential scanning calorimetry (DSC), X-ray diffractometer (XRD), scanning electron microscope (SEM), and multifunction LCR meter. The results reveal that crystallization mechanism of this glass is believed to be three-dimensional interfacial growth. It was observed that predominant crystalline phase is Ba_0.39Sr_0.61Nb₂O₆ in these glass-ceramics crystallized at 750 °C, and the grain size increases with increase in crystallization time. The uniform microstructure can be seen clearly in glass-ceramics crystallized at 750 °C for 3 h, and the obtained glass-ceramics was found to possess optimal properties. Moreover, glass-ceramic with a dielectric constant of 58, the dielectric loss of 0.007 and breakdown strength of 1010 kV/cm could be achieved. In addition, energy storage density of glass-ceramics reached a maximal value of 2.62 J/cm³. To our knowledge, studies on SrO-BaO-Nb₂O₅-B₂O₃ glass-ceramics without SiO₂ as a glass network former are few, and the melting temperature of the B₂O₃-based glass is lower than that of SiO₂-based glass, which is conducive to the purpose of energy saving. These findings indicate that this glass may be a candidate for high energy-storage capacitors.