用热水示踪技术测量蒸馏塔板上液体返混的微机温度测量装置

对测量塔板上液体返混的温度测量仪进行了调试研究,仪器的测量精度为1.5级,时间常数为4.0～4.8s,相对滞后时间为0.05～0.3s。仪器有良好的重复性和分辨能力,采用激励一响应技术用热水做示踪．通过对涡流扩散系数测试值和计算值的比较,仪器的测量结果准确可靠。     

Na2GdMg2V3O12:Sm3+ phosphors for three-mode optical temperature sensing

Multi-mode optical thermometry is emerging as a promising technique for accurate temperature measurement. Here, a series of Na₂GdMg₂V₃O₁₂:Sm³⁺ (NGMVO:xSm³⁺) phosphors with dual-emission centers were successfully elaborated. Irradiated by 349 nm light, NGMVO:Sm³⁺ can generate emissions from VO₄³⁻ and Sm³⁺ simultaneously due to energy transfer between them. Benefitting from difference of thermal quenching performance of two luminescent centers, fluorescence intensity (FI), fluorescence intensity ratio (FIR), and Commission Internationale de L'Eclairage coordinate modes of NGMVO:Sm³⁺ thermometer were designed. Maximum relative sensitivities (S_R) are found to be as high as 2.21 %K⁻¹, 2.12 %K⁻¹, and 0.244 %K⁻¹, respectively. Besides, with temperature increasing, S_R values of FI and FIR modes decrease slowly. Their minimal S_R values between 303 and 513 K maintain above 1.36 %K⁻¹ and 1.08 %K⁻¹, respectively. Our findings reveal that NGMVO:Sm³⁺ phosphors have promising applications for multimode temperature senor.     

利用热电器件实现发射率及温度的实时测量系统

介绍了一种采用钽酸锂热释电探测器作为光接收元件、以 80 31单片机为核心实现的中、高温物体发射率及温度实时测量系统。介绍了其工作原理与结构 ,分析了其中的技术难点及相应的解决方法 ,讨论了系统的灵敏度、发射率及温度的测量精度。结果表明 ,对 42 7℃抛光的钢铸件而言 ,系统的最小可鉴别温差为 0 .32 K,发射率的测量精度 σελ=1 .72× 1 0 -2 ,|σελ/ελ| 2 .6% ;温度的测量精度σT=1 .8k,|σT/T| 0 .2 575%。     

变压器用测温装置的校准方法研究

研究了变压器用测温装置远方与就地示值偏差的产生机理,提出了以油温计示值为参照点,对具有多点调零功能的温度转换模块进行现场校准的消缺方法.     

Abnormal upconversion luminescence induced by defects and Er3+–Yb3+ distance change in Cs3GdGe3O9:Er3+/Yb3+ phosphors

A series of Er³⁺/Yb³⁺ co-doped Cs₃GdGe₃O₉ (CGG) phosphors were prepared by solid-phase sintering method, and the microstructure and upconversion luminescence (UCL) properties were tested by variable-temperature X-ray diffractometry and variable-temperature spectrometer. Abnormal UCL phenomena were found, which include UCL intensity continuously increasing under 980 nm laser continuous irradiation and UCL thermal enhancement. After 10 min of continuous irradiation by 980 nm laser at 513 K, the UCL intensity increased 2.91 times compared with the initial UCL intensity. The phenomenon is due to the electron releasing of host defects. The green UCL intensity of CGG:0.1Er³⁺/0.2Yb³⁺ decreases at 303–423 K and increases at 423–723 K, which reaches 13.23 times compared with that at 423 K. The phenomenon is due to Er³⁺–Yb³⁺ distance change by temperature and phonon-assisted transitions. In addition, the absolute temperature sensitivities of samples are calculated by luminescence intensity ratio technology, the maximum absolute sensitivity of CGG:0.1Er³⁺/0.4Yb³⁺ is 0.00691 K⁻¹ at 546 K, and the maximum relative sensitivity of CGG:0.1Er³⁺/0.1Yb³⁺ is 0.01224 K⁻¹ at 303 K. These results indicate that CGG:Er³⁺/Yb³⁺ phosphors can be used as a high-temperature optical thermometer.     

Improved optical thermometric sensitivity of Eu3+-doped calcium niobate phosphor via nonstoichiometric control

Eu³⁺-doped calcium niobate CaNb_xO₆ phosphors were successfully prepared by a solid-state reaction, and the crystal structure, morphology, energy transfer process, and temperature-dependent behaviors were systematically investigated. The CaNb_xO₆ host matrix presents the self-activated characteristic emission at 470 nm due to the charge transfer transition of Nb⁵⁺–O²⁺, and the corresponding photoluminescence intensity reaches the maximum intensity when the nonstoichiometric ratio of Ca²⁺/Nb⁵⁺ ions is 1:1.9. Moreover, the energy transfer process from the host (470 nm) to Eu³⁺ (612 nm) ions in the CaNb_1.9O₆:Eu³⁺ phosphor is demonstrated, and the corresponding energy transfer efficiency is significantly enhanced compared with that of stoichiometric sample. Furthermore, it is observed that nonstoichiometric ratio of Nb⁵⁺ ions deteriorates the thermal quenching of the matrix while guaranteeing the thermal stability of the activators, resulting in the relative sensitivity (S_r) of CaNb_1.9O₆:Eu³⁺ being greatly improved from 2.235% to 3.673% K⁻¹. Herein, these results provide an effective strategy for manipulating the sensitivity of optical thermometers of phosphors based on the induced modulation of the temperature-response performance via nonstoichiometric control.