排序方式: 共有71条查询结果,搜索用时 281 毫秒
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用LM35D集成温度传感器制作数字温度计 总被引:2,自引:0,他引:2
介绍LM35D集成温度传感器的性能测试和制作数字温度计的方法。 相似文献
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Most established NMR thermometers rely on temperature-dependent chemical shift differences measured from samples that are either neat or concentrated solutions (e.g. ethylene glycol, methanol). These are unsuitable for modern cryoprobes on account of strong radiation damping resulting from the high Q of the probe. Using perdeuterated methanol, we established a relationship between the chemical shift difference and temperature, and we show that this relationship is well fitted by a quadratic equation. The actual temperature within a sample tube in the probe was verified using a Pt-100 resistor. 相似文献
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Real-time imaging of the spatial distribution of rf-heating in NMR samples during broadband decoupling 总被引:1,自引:0,他引:1
Continuous radio-frequency (rf) irradiation during decoupling and spin-lock periods in NMR pulse sequences may lead to undesired sample heating. Heat-sensitive samples can suffer damage from the sudden temperature rise which cannot be adequately compensated by the temperature control system. Moreover, as the heating is spatially inhomogeneous, higher temperature increases can arise locally than are indicated by the average increase detected by the temperature controller. In this work we present a technique that allows measurement of a real-time 2D-image of the temperature distribution inside an NMR sample during an experiment involving rf-heating. NMR imaging methods have previously been used to project the temperature distribution inside an NMR sample onto a single spatial axis or to acquire steady-state 2D- temperature distributions. The real-time 2D-temperature profiles obtained with our procedure provide much more detailed data. Our results show, that not only inhomogeneous heating but also inhomogeneous sample cooling contribute to the build-up of temperature gradients across the sample. The technique can be used to visualize rf-heating in order to protect sensitive samples and to experimentally test new coil geometries or to guide probehead design. 相似文献
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D Cauzzi R Pattacini M Delferro F Dini C Di Natale R Paolesse S Bonacchi M Montalti N Zaccheroni M Calvaresi F Zerbetto L Prodi 《Angewandte Chemie (International ed. in English)》2012,51(38):9662-9665
The heat is on: A Cu(5) metal cluster presents distinctive photophysical properties that result in a temperature-dependent fluorescent quantum yield and excited-state lifetime between -45 and +80?°C, both in solution and as a solid. Unprecedented accuracy in temperature determination by fluorescence measurements was achieved with this complex, thus making it suitable for applications in, for example, biology and (nano)materials research. 相似文献
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以Pt电阻温度传感器(Pt-111)为研究对象,研究了其在0~16T磁场下、4.2~300K温区内的磁致电阻效应.结果表明:Pt-111在0~16T场强、4.2~77K温区内,磁效应随场强的增加和温度的降低而明显升高,77~300K温区内温度计受磁场的影响较小,其中在16T下,4.2K和300K处的磁效应分别为48.2%和1.07%;在4.2-77K温区,Pt-111由磁阻引起的测量误差场强的升高和温度的降低而明显升高,在16T、4.2K处和16T、77K处的温度测量误差分别为18.3K和1.69K.Pt-111不推荐应用在77K以下的磁场环境. 相似文献
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13C‐TmDOTA as versatile thermometer compound for solid‐state NMR of hydrated lipid bilayer membranes
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Yuichi Umegawa Yuya Tanaka Matsumori Nobuaki Michio Murata 《Magnetic resonance in chemistry : MRC》2016,54(3):227-233
Recent advances in solid‐state nuclear magnetic resonance (NMR) techniques, such as magic angle spinning and high‐power decoupling, have dramatically increased the sensitivity and resolution of NMR. However, these NMR techniques generate extra heat, causing a temperature difference between the sample in the rotor and the variable temperature gas. This extra heating is a particularly crucial problem for hydrated lipid membrane samples. Thus, to develop an NMR thermometer that is suitable for hydrated lipid samples, thulium‐1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetate (TmDOTA) was synthesized and labeled with 13C (i.e., 13C‐TmDOTA) to increase the NMR sensitivity. The complex was mixed with a hydrated lipid membrane, and the system was subjected to solid‐state NMR and differential scanning calorimetric analyses. The physical properties of the lipid bilayer and the quality of the NMR spectra of the membrane were negligibly affected by the presence of 13C‐TmDOTA, and the 13C chemical shift of the complex exhibited a large‐temperature dependence. The results demonstrated that 13C‐TmDOTA could be successfully used as a thermometer to accurately monitor temperature changes induced by 1H decoupling pulses and/or by magic angle spinning and the temperature distribution of the sample inside the rotor. Thus, 13C‐TmDOTA was shown to be a versatile thermometer for hydrated lipid assemblies. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Helmut Quast Markus Heubes Anita Dunger Hans-Heinrich Limbach 《Journal of magnetic resonance (San Diego, Calif. : 1997)》1998,134(2):236-244
The first carbon-13 shift thermometer for the temperature range of 100–300 K is based on the very rapid equilibration of a pair of semibullvalene valence tautomers. The temperature dependence of the equilibrium constant is reflected in strongly temperature-dependent shift differences Δδ between averaged signals, e.g.,d(Δδ)/dT= 0.051 ppm K−1at 300, 0.087 ppm K−1at 200, and 0.175 ppm K−1at 110 K for the quaternary carbon atoms C2 and C6. At 37 temperaturesT, which were measured with calibrated platinum resistance thermometers, shift differences Δδ were taken from nondecoupled carbon-13 spectra recorded from solutions of 1 in mixtures of chlorodifluoromethane and deuterated dimethyl ether without spinning. The least-squares fit of these Δδ vsTdata to a polynomial equation of the fourth degree (Eq. [5],r2= 0.9999) allows the calculation of temperatures from measured shift differences with a standard deviation of 0.46 K and an estimated error of about 1 K. The heating effects of WALTZ-16 decoupling and the influence of solvents on Δδ are investigated. A comparison with existing NMR thermometers demonstrates the superior performance of the new carbon-13 shift thermometer with respect to precision and the accessible temperature range. 相似文献
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Dr. Yuichi Kitagawa Marina Kumagai Pedro Paulo Ferreira da Rosa Prof. Dr. Koji Fushimi Prof. Dr. Yasuchika Hasegawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(1):264-269
A design for an effective molecular luminescent thermometer based on long-range electronic coupling in lanthanide coordination polymers is proposed. The coordination polymers are composed of lanthanide ions EuIII and GdIII, three anionic ligands (hexafluoroacetylacetonate), and a chrysene-based phosphine oxide bridges (6,12-bis(diphenylphosphoryl)chrysene). The zig-zag orientation of the single polymer chains induces the formation of packed coordination structures containing multiple sites for CH-F intermolecular interactions, resulting in thermal stability above 350 °C. The electronic coupling is controlled by changing the concentration of the GdIII ion in the EuIII-GdIII polymer. The emission quantum yield and the maximum relative temperature sensitivity (Sm) of emission lifetimes for the EuIII-GdIII polymer (Eu:Gd=1:1, Φtot=52 %, Sm=3.73 % K−1) were higher than those for the pure EuIII coordination polymer (Φtot=36 %, Sm=2.70 % K−1), respectively. Enhanced temperature sensing properties are caused by control of long-range electronic coupling based on phosphine oxide with chrysene framework. 相似文献