International comparison of quantum AC voltage standards for frequencies up to 100 kHz

This paper presents results of an international comparison of two quantum AC voltage standards based on pulse-driven Josephson arrays. The two systems differ in several hardware and software characteristics as well as in the level of automation, features which can influence the accuracy of transferring the quantum-standard voltage value to a calibrated instrument. The comparison was performed at 100 mV, 20 mV and 12 mV, at frequencies between 2.5 kHz and 100 kHz. An electronically-aided thermal transfer standard was used as a travelling standard. At the most accurate voltage and frequency point, 100 mV at 2.5 kHz, both laboratories agreed to better than 1 part in 10⁶.     

The 250 kN primary shock force calibration device at PTB

A new facility for primary shock force calibrations up to a force amplitude of 250 kN is presented. Shock forces are generated by the impact of two airborne cylindrical mass bodies. Two laser-Doppler interferometers simultaneously measure the bodies’ dynamic motions on their common axis of motion. Traceability of force is realised by the determination of mass and acceleration. This paper is an extended version of the original contribution to the IMEKO 2010 conference in Pattaya, Thailand.     

Simple apparatus to measure Seebeck coefficient up to 900 K

An apparatus for measuring Seebeck coefficient (S) has been designed that allows measurement of S from room temperature to 900 K. It is constructed from readily available equipment and instrumentation with parts that can be easily fabricated. The details of instrument fabrication, sources of errors, method of calibration, typical measurement in test sample are described. We report the Seebeck coefficient measurement of Ca-cobaltite (Ca₃Co₄O₉) a p-type thermoelectric material. The obtained results from the fabricated setup are well matched with the reported and standard instrument data with standard deviation of ±3%.     

Frictional force microscopic detection of anisotropy at NaCl (1 0 0), (1 1 0) and (1 1 1) surfaces

Frictional coefficients were measured at atom-flat NaCl (1 0 0), (1 1 0) and (1 1 1) surfaces with frictional force microscopy. At the electrically neutral (1 0 0) and (1 1 0) surfaces in 15% relative humidity, lower friction was detected along 1 1 0 direction where the same kind of ions are aligned, than along 1 0 0 direction where different ions alternate. Low and isotropic friction was observed at the polar (1 1 1) surface. The results were explained by the gradients of electrostatic interaction potentials between a dipole at the tip and the ions at the surface. Toward higher relative humidity up to 60%, frictions at the (1 0 0) surface decreased indicating lubrication effect by water. The changes observed for the (1 1 0) surface suggested presence of adsorbed water in stripe pattern along the 1 1 0 direction. In the higher humidity range, frictional force increased at all the surfaces, probably due to larger normal force caused by the meniscus force.     

Evaluation of newly developed 50 N dead-weight type force standard machine using tuning-fork type force transducer

A 50 N dead-weight type force standard machine (DWM) was developed by the National Metrology Institute of Japan to expand the lower end of calibration force from 10 N to 1 N. The weights of the DWM consisted of a loading frame and a linkage-weight stack. The loading frame applied a gravitational force of 1 N to a force transducer under calibration. The calibration and measurement capability of the 50 N DWM was verified to be 2 × 10⁻⁵ relative using a tuning-fork type force transducer in accordance with ISO 376. The equivalence between the 50 N and 500 N DWMs was confirmed by performing an intralaboratory comparison using the tuning-fork type force transducer. Moreover, the competence of the transducer for the evaluation of DWMs was demonstrated.     

谈企业产品标准编制说明的编写

根据《标准化法》第二章第六条的规定“企业的产品标准须报当地政府标准化行政主管部门和有关行政主管部门备案”。按照《企业标准化管理办法》第三章第十六条的规定“报送企业产品标准备案的材料有：备案申报文、标准文本和编制说明等”。但对     

A novel automatic mass comparator with a resolution of 10 ng for calibration of masses below 2 mg

This paper presents a novel mass comparator designed for the purpose of measuring small weights of 2 mg and lower, with readability of 10 ng. The mass comparator was developed using new types of coil and actuator. The added protective ring decreased the average sorption-induced mass variation for the coil by 84%. The accuracy of the novel comparator was verified in terms of stability, Type An uncertainty, and repeatability. Compared to the device of the best available accuracy, the standard uncertainties of the novel-design comparator were approximately 70% narrower.     

Measurement of thermoelectric power of solids up to 10 GPa

A method of measuring thermoelectric power of solids as a function of pressure up to nearly 10 GPa is described. A tungsten carbide opposed anvil setup is used to generate the pressure.     

Uncertainty evaluation of a 10N·m dead weight torque standard machine and comparison with a 1kN·m dead weight torque standard machine

A 10N·m dead weight torque standard machine (10-N·m-DWTSM) has been developed and evaluated since 2006 at the National Metrology Institute of Japan (NMIJ), a part of the National Institute of Advanced Industrial Science and Technology (AIST). Previously, the lengths of a moment arm, made of a low-thermal-expansion alloy (Super Invar), and the sensitivity limit of the fulcrum were evaluated. However, it is known that mechanical parts made of Super Invar vary in size with time. Therefore, the sensitivity limit of the fulcrum should be investigated under real calibration conditions. In this study, the moment arm lengths and the sensitivity limit of the fulcrum were re-evaluated. The moment arm lengths were found to have increased by an average of 6.3 μm in five years. The relative combined standard uncertainty of the moment arm length, w_arm, was re-evaluated in consideration of the uncertainty of the secular length change and was found to be 1.8 × 10⁻⁵. The sensitivity limit of the fulcrum was investigated by using a highly accurate, small-rated-capacity torque measuring device. The relative combined standard uncertainty due to the sensitivity limit of the fulcrum was 2.5 × 10⁻⁵ in the 0.1–10N·m torque range. The uncertainty budget table of the 10-N·m-DWTSM was completed. The relative expanded uncertainty of torque realized by the 10-N·m-DWTSM, W_tsm, was evaluated in the 0.1–10N·m torque range and was found to be 6.6 × 10⁻⁵, with a coverage factor, k, being equal to 2. In addition, the 10-N·m-DWTSM was compared with the existing 1-kN·m-DWTSM at NMIJ by using small-rated-capacity torque measuring devices at 5N·m and 10N·m torque steps. Two loading conditions were adopted in this comparison. The comparison results showed good agreement within the uncertainties in all cases. Thus, the torque realized by the 10-N·m-DWTSM was shown to be equivalent to that achieved by the 1-kN·m-DWTSM.     

大力开展“四达标”活动向设备管理要效益

中国长城铝业公司开展设备操作维护达标、设备检修达标、设备及环境卫生达标和设备台时产能达标的设备管理"四达标"活动,实行激励和约束机制,取得了非常显著的经济效益和社会效益.     

Practical limitations of superresolution imaging due to conventional sample preparation revealed by a direct comparison of CLSM,SIM and dSTORM

We evaluate the suitability of conventional sample preparation and labelling methods for two superresolution techniques, structured illumination microscopy and direct stochastic optical reconstruction microscopy, by a comparison to established confocal laser scanning microscopy. We show that SIM is compatible with standard fixation procedures and immunofluorescence labelling protocols and improves resolution by a factor of two compared to confocal laser scanning microscopy. With direct stochastic optical reconstruction microscopy, fluorophores can theoretically be localized with much higher precision. However, in practice, with indirect immunofluorescence labelling density can be insufficient due to the bulky probes to reveal biological structures with high resolution. Fine structures like single actin fibres are in fact resolved with direct stochastic optical reconstruction microscopy when using small affinity probes, but require proper adjustment of the fixation protocol. Finally, by a direct comparison of immunofluorescent and genetic labelling with fluorescent proteins, we show that target morphology in direct stochastic optical reconstruction microscopy data sets can differ significantly depending on the labelling method and the molecular environment of the target.     

Application and uncertainty analysis of a balance weighing system used in natural gas primary standard up to 60 bar

A new 3-ton balance weighing system was designed and built up for a high level mass-time primary standard of natural gas up to 60 bar in CVB. The system is composed of a 3-ton electromagnetic balance, two tanks with thermal isolation, two platforms, two roller guide rails and two big weights which are used for special test. To achieve a lower uncertainty and the security application in natural gas measurement, several special methods were used in the system. Firstly, the tanks and platforms can be moved together steadily on the roller guide rail to be connected with pipeline system or to be weighted by the balance which also reduces the pipeline length between tanks and pipeline system. Secondly, the substitute weighing method is used for high accurate weighing. Finally, the whole system is located in a thermal isolated room with temperature and humidity controlling. Technical details, performance tests, uncertainty analysis and the future improvement ideas of the balance system are presented in the paper. The uncertainty analysis shows that the mass measurement uncertainty of gas can achieve less than 1.0g and the maximum relative standard uncertainty of natural gas mass measurement would be no more than 0.022%.     

Vibration and stability of an Euler–Bernoulli beam with up to three-step changes in cross-section and in axial force

The paper treats the vibration of beams with up to three-step changes in cross-section and in which the axial force in each portion is constant but different. The system parameters are the step positions, the flexural rigidity, the mass per unit length and the axial force in the beam portions—all of which were normalized. The frequency equation for 16 combinations of classical boundary conditions are expressed as fourth-order determinants equated to zero. The first three frequency parameters are tabulated for sets of system parameters (arbitrarily chosen and which includes a stepped beams under tensile or compressive axial end force). Critical compressive end force which causes a stepped beam to buckle are tabulated. Buckling under a system of axial forces, one of which is critical is discussed and several critical combinations of the system parameters are tabulated. Beams of constant depth and step change in breadth, of constant breadth and step change in depth and shafts with step change in diameter are considered. It is shown that stepped shafts are inferior machine elements if dynamic properties are the prime consideration.     

Differential pressure comparison from 5 Pa to 500 Pa with a liquid column manometer between CENAM (Mexico) and INTI – Fisica y Metrologia (Argentina)

A differential pressure comparison was performed between CENAM (Mexico) and INTI (Argentina) by means of a liquid column manometer. The measuring range was 5–500 Pa. CENAM calibrated the transfer standard at the beginning and at the end of the comparison. The transfer standard used was a Dwyer liquid column manometer model Microtector with an accuracy class of 0.013% of the reading. The compared pressure points were (5, 75, 125, 200, 250, 300, 350, 400, 450, 500) Pa. The uncertainty sources to be evaluated included at least the following: (a) Uncertainty due to the standard used by the laboratory; (b) Uncertainty due to repeatability; (c) Uncertainty due to resolution; (d) Uncertainty due to hysteresis; (e) Uncertainty due to zero drift. The criteria used to compare the results obtained were the normalized error equation (E_n). The results obtained by the laboratories were compatible according to the criteria |E_n| ? 1.     

Bilateral comparisons of measurement capabilities for the calibration of low nominal capacity torque measuring devices between NMIJ and PTB in the range from 0.1 N m to 10 N m using different procedures

Bilateral comparisons of the calibration of low nominal capacity torque measuring devices (TMDs) were conducted between NMIJ and PTB for the first time. A 10 N m deadweight torque standard machine (TSM) newly developed at NMIJ was compared with PTB’s two TSMs with nominal capacities of 1 N m and 1 kN m, in the range from 0.1 N m to 10 N m. The transfer measurement devices used had nominal capacities of 1 N m and 10 N m. The comparisons were made using two calibration procedures: one based on the CCM.T-K2 Key Comparison procedure and the other according to the daily calibration procedure adopted at each institute. As a result, the torque realized by the TSM at NMIJ was shown to be equivalent to that realized by the two TSMs at PTB. In addition, it was confirmed that the daily calibration procedures of both institutes yielded consistent results in the calibration of low nominal capacity TMDs.     

Electrical feedthrough for gas pressures up to 10 000 bar and low temperatures

An electrical gas-tight feedthrough is described which is suitable for use at pressures up to 10 000 bar and temperatures down to -180 degrees C. The capacitance of the feedthrough is about 20 pF.     

Proposal for the direct comparison of the standards of,capacitance and inductance to ac QHR

The representation of the ohm by the quantum Hall effect permits the reproduction of the farad unit by tracing capacitance to dc resistance. Many R–C bridge’s types are used in these determinations. In effect a chain of some bridges must be used.     

Development of an x-ray diffraction camera used in magnetic fields up to 10 T

A high-field x-ray diffraction (HF-XRD) camera was developed to observe structural changes of magnetic materials in magnetic fields up to 10 T. The instrument mainly consists of a Debye-Scherrer-type camera with a diameter of 80.1 mm, a 10-T cryocooled superconducting magnet with a 100-mm room-temperature bore, an x-ray source, a power supply, and a chiller for the x-ray source. An x-ray detector (image plate) in the HF-XRD camera can be taken out and inserted into the magnet without changing the sample position. The performance of the instrument was tested by measuring the HF-XRD for silicon and ferromagnetic MnBi powders. A change of x-ray diffraction pattern was observed due to the magnetic orientation of MnBi, showing that the instrument is useful for studying field-induced orientation processes and structural properties of field-controlled materials.