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介绍了DM A Q800动态机械热分析仪的维护,对常见问题进行了探讨。维护主要涉及低温冷却附件(GCA)、空压机(ACA)以及Q800本身,常见问题主要是如何通过合理的制样以及装载样品来获得更准确的测试结果,掌握维护及如何制样装载样品既能得到准确的测试结果,同时也能延长仪器使用的寿命和降低仪器使用不当对操作者造成的伤害。 相似文献
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核磁共振成像是一种先进的影像检查方式,其广泛用于医学检查和化学检查领域。核磁共振系统主要由磁体部分、磁共振波谱仪部分及数据处理部分组成,而磁体部分主要是通过主磁体提供磁场进行工作。本文对核磁共振成像超导磁体设计方法进行了分析研究。 相似文献
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仪器管理是保证环境监测实验室出具数据有效性的重要环节,针对仪器配置、验收、使用、维护、量值溯源、档案管理和报废过程中常见问题,结合日常仪器管理工作,提出实践方法和建议。 相似文献
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文章介绍了一种新型太阳辐射模拟器的整体构造和技术指标;详细阐述了其性能测试方法,包括光源的光谱分布、辐照度范围、均匀性和稳定性等性能;同时对测试仪器、测试方法、测试结果以及常见问题的解决方法进行了分析和总结。 相似文献
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针对流动注射仪重复性差的问题,经过一系列标准液分析、仪器处理、实验测试,找出原因。强调标准操作以及仪器日常维护的重要性,希望可供相关从业者参考借鉴。 相似文献
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风电齿轮箱作为风机的重要组成部分,是机组的核心部件之一,故加强对其的维护和保养十分必要。但是,由于风机工作环境恶劣,在运转的过程中常常会受到多种因素的影响,造成运转问题出现。考虑到齿轮箱的维护和更换成本,在事故发生之前对问题进行解决十分必要。而通过噪声监测来达到“以噪带震”检测齿轮箱的方法是一种可选的途径。本文针对风电机组的齿轮箱噪声测试系统设计问题进行简要分析,探究噪声检测构成以及设计原理,以此提升相关工作效能。 相似文献
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为了获得有效的超导磁体运行的低温环境,文中介绍了低温超导磁体杜瓦装置的结构设计和传热分析,研制了一套采用真空多层绝热、铜辐射冷屏、蛇形排气管结构形式的绝热系统.通过传热理论计算表明,液氦的损耗量小于技术要求的0.9L/h指标,能够保证超导磁体系统能够在一定的低温环境下长日时间的运行. 相似文献
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圆简件是电站锅炉广泛应用的一种部件,其焊接质量关系到产品的安全运行.对其焊接质量的内部检测主要依赖于无损检测技术.分析了圆简件超声波检测的困难,提出了解决这些困难的方法,制订了有针对性的检测工艺,较好地满足了检测要求. 相似文献
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针对钢丝绳应用及检测过程中安全性能、利用率、检测精度等问题,综合分析了现阶段钢丝绳无损检测国内外相关研究成果,总结并提出了今后的研究方向。首先,介绍了无损检测技术当前在实际工程中的应用,具体对比分析了两种主流探伤仪技术特点,以及在桥梁建筑等行业中的应用;接着,介绍了现在无损检测技术发展状况,着重论述了钢丝绳磁检测技术和非磁检测技术研究和应用现状,其中磁检测技术主要包括电磁法和永磁法,非磁检测主要包括电流法、声发射法和声-超声检测法;最后,在对比当前无损检测研究方法的基础上提出了集中钢丝绳无损检测的可行方法,指出了发展声-超声检测技术的研究趋势。 相似文献
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Tinschert K Lang R Mäder J Rossbach J Spädtke P Komorowski P Meyer-Reumers M Krischel D Fischer B Ciavola G Gammino S Celona L 《The Review of scientific instruments》2012,83(2):02A319
The production of intense beams of heavy ions with electron cyclotron resonance ion sources (ECRIS) is an important request at many accelerators. According to the ECR condition and considering semi-empirical scaling laws, it is essential to increase the microwave frequency together with the magnetic flux density of the ECRIS magnet system. A useful frequency of 28 GHz, therefore, requires magnetic flux densities above 2.2 T implying the use of superconducting magnets. A cooperation of European institutions initiated a project to build a multipurpose superconducting ECRIS (MS-ECRIS) in order to achieve an increase of the performances in the order of a factor of ten. After a first design of the superconducting magnet system for the MS-ECRIS, the respective cold testing of the built magnet system reveals a lack of mechanical performance due to the strong interaction of the magnetic field of the three solenoids with the sextupole field and the magnetization of the magnetic iron collar. Comprehensive structural analysis, magnetic field calculations, and calculations of the force pattern confirm thereafter these strong interactions, especially of the iron collar with the solenoidal fields. The investigations on the structural analysis as well as suggestions for a possible mechanical design solution are given. 相似文献
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Construction and calibration of a 12 T pulsed magnet integrated with a 4 K closed-cycle refrigerator
A low cost 12 T pulsed magnet system has been integrated with a closed-cycle helium refrigerator for performing magnetotransport measurements. Minimal delay between pulses and ac current excitation with software lock-in to reduce noise enables quick but accurate measurements to be performed at temperatures of 4-300 K up to 12 T. An additional pulsed magnet operating with a liquid nitrogen cryostat extends the range up to 19 T. The instrument has been calibrated against a commercial superconducting magnet by comparing quantum Hall effect data in a p-channel SiGe/Si heterostructure, and common issues arising out of pulsed magnet usage have been addressed. The versatility of the system is demonstrated through magnetotransport measurements in a variety of samples such as heterostructures, narrow gap semiconductors, and those exhibiting giant magnetoresistance. 相似文献
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Maria Victoria Silva Elipe Neil Donovan Robert Krull Donald Pooke Kimberly L. Colson 《仪器科学与技术》2019,47(2):195-212
Nuclear magnetic resonance (NMR) is a powerful technique for the structure elucidation of organic molecules and significantly important in the pharmaceutical industry supporting the discovery and development of drug substances or active pharmaceutical ingredients (APIs). Following an initial study and assessment of a prototype NMR instrument with a high-temperature superconducting (HTS) power-driven magnet of 9.4?T (400?MHz for 1H observation) operating with standard commercial electronics and probes, we tested the instrument with three compounds representing typical pharmaceutical drugs. We compared results from two probes and shimstacks with different geometries (broadband fluorine observe (BBFO) with Bruker orthogonal shim system-3 (BOSS3) and Bruker quattro nucleus probe (QNP) with BOSS1 shims) testing standard one-dimensional (1D) NMR experiments including selective excitation experiments, and two-dimensional (2D) homonuclear and heteronuclear experiments for the purposes of evaluating the equipment for structure elucidation capabilities. In our initial study on cinacalcet HCl, only the 1D 1H experiment showed a loss of resolution when using the longer coiled BBFO probe with the BOSS3 shims compared to the shorter coiled QNP probe with BOSS1 shims. The selective excitation experiments using the cinacalcet HCl were successful. Our characterization of 1D (1H, 13C, 19F) and 2D (1H-1H and 1H-13C) NMR experiments for compounds I and II with the two probes and shimstacks indicated no significance differences. Overall, these results are satisfactory with the HTS magnet at the field of 9.4?T for the structural elucidation work of standard pharmaceutical compounds. This new technology has the advantage of being able to locate the HTS NMR magnet system in any chemistry or analytical laboratory where the samples are produced, facilitating rapid analysis with minor needs from the facilities and without cryogenic liquids. 相似文献
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M. I. Surin V. E. Keilin S. M. Miklyaev S. A. Shevchenko 《Instruments and Experimental Techniques》2008,51(4):634-637
Within the framework of the “International Thermonuclear Experimental Reactor” (ITER) program, a prototype of a superconducting magnet for a 170-GHz gyrotron has been developed, manufactured, and tested. The operating induction value (7.1 T at the center of a 219-mm-diameter cold hole and 8.1 T on the winding) is reached at a current of 185.2 A. In the final version of the magnet, the required induction value was reached without aging. Special requirements are imposed on the distribution of the magnetic field along the axis, including an abrupt field decrease on both sides of the magnet. Axial forces are additionally taken by a special device. The magnet’s sections are wound with multifiber conductors based on niobium-tin and niobium-titanium alloys. Seventeen resistive shunts are provided for protecting sections during their transition to the normal state. The magnet is equipped with a device for removing a part of energy from the sections. Mechanical stresses in the magnet’s sections and the structure’s power elements have been measured during tests. 相似文献
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Ploumbidis D 《The Review of scientific instruments》1979,50(9):1133-1135
In the course of constructing an apparatus suitable for studies of nuclear magnetic resonance at high temperatures and high fields we developed a furnace with a new heating element which has been applied for the first time to NMR studies. The furnace can work in a 8-T field of a superconducting magnet system at temperatures up to 2200 K. Because of its geometrical form the heating element does not cause any measurable disturbing magnetic fields resulting from the heating current, and has many advantages compared to conventional heating elements. The temperature at which, up to this moment, we could observe NMR in external fields of 8 T amounts to 1200 K. The specifically adapted NMR probe works at radio frequencies up to 50 MHz. With this apparatus we carried out measurements of the magnitude, sign, and temperature dependence of the Knight shift of Mo in molybdenum metal. 相似文献