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Main text This is the final report of CCT-K7.2021 key comparison of water-triple-point (TPW) cells. The primary objective of CCT-K7.2021 was a comparison of the participant national realizations of the TPW temperature. Each participant laboratory selected one of its TPW cells for use as a transfer cell, directly compared it against its national reference and delivered it to the pilot (NRC). The pilot then compared all transfer cells against two NRC reference cells and, finally, each participant laboratory retrieved its transfer cell and directly re-compared it against its TPW national reference. The initial measurements at the participant laboratories were started in April 2021. The final measurements at the participants' laboratories were completed in September 2022. The final report was approved by the CCT WG-KC in April 2023. The adaptive weighted average procedure was adopted to compute the Key Comparison Reference Value (KCRV) and the degrees of equivalence (DoEs) were reported for the participant laboratories. The maximum difference between two transfer cells was 92 μK with a standard deviation of 26 µK (almost a factor of two improvement compared to CCT-K7 results (2002-2004). The maximum difference between two TPW national realizations was 111 µK, with a standard deviation of 28 µK (improvement similar to the one reported for the transfer cells). While the pooled distribution of CCT-K7 results was bimodal, indicating the presence of two different sub-populations (the population of laboratories that referred to ocean water definition and the population of laboratories that did not consider it), the pooled distribution of CCT-K7.2021 results was no longer bimodal, but slightly asymmetrical, indicating a more harmonized approach to water isotopic corrections. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

The action of the Minamata Convention requests in the near term to develop alternative fixed points to replace the mercury triple point (Hg TP) from the set of the defining points of the International Temperature Scale (ITS) of 1990. Carbon dioxide (CO2) TP is a candidate that exhibits the advantages of high chemical and physical stability and low health risk, and the disadvantage of relatively high pressure at room temperature. We report our study on the realization of the CO2 TP using long-stem standard platinum resistance thermometers (SPRTs). We present a novel design for a CO2 TP cell with thermometer immersion depth extending from 110 –200 mm with no increase in sample gas pressure. The outer dimension of the new cell is suitable for a drop-in compatible replacement of a normal cell for the Hg TP. We realized 14 plateaus of the CO2 TP using two long-stem SPRTs over a span of 12 months. The mean temperature at the CO2 TP is 216.591 30 (36) K at the melt fraction F = 0.5 and 216.591 36 (37) K at F = 1.0. Within the given uncertainties, the uncertainty arising from the transformation to ITS-90 contributes a major part of 0.29 –0.30 mK. The uncertainty formed by the pressure-head effect and the axial heat leak through the thermometer well of the new cell, the impurities of the sample gas and the inaccuracy of the electronic instruments contribute a smaller part of 0.21 –0.22 mK. The plateaus consistently exhibit small slopes of heights of less than 0.21 mK and time spans from 147 –347 h between F = 0.3 and F = 0.75. The small slopes of the plateaus demonstrate the repeatability of 0.056 and 0.059 mK, respectively, for the melt fraction F = 0.5 and 1.0, and the long-term stability of 0.031 mK.

The triple points of carbon dioxide (CO2 TP) and sulfur hexafluoride (SF6 TP) are candidate substitutes for the triple point of mercury from the set of defining points of the international temperature scale of 1990. For the replacement to be successful, the measurement performances of CO2 TP and SF6 TP need to be improved. Compounds of CO2 and SF6 contain different isotopes of carbon, oxygen and sulfur. They fractionate in the solid and liquid phase of the compounds and shift the phase transition temperatures. Thus, the isotopic effect is a probable cause for inconsistency of measurements of CO2 TP and SF6 TP, which has motivated us to investigate it. According to the reported fractionation factors and abundances of isotopes, we predict the temperature corrections to vary from − 0.023 mK to 0.051 mK for measurements of the CO2 TP. This narrow variation implies that the refining process causes only an insignificant change compared with the natural abundances of the minority isotopes 13C and 18O in the source gas. Consequently, the small change will probably cause a minor inconsistency for measurements of the CO2 TP. By contrast, for measurements of the SF6 TP the predicted temperature corrections range from − 0.022 mK to 1.223 mK. Our predictions suggest that further investigations of the isotopic effect on measurements of the TP of CO2 and the TP of SF6 are desirable, particularly for the latter molecule.

Two-photon absorption spectra are difficult to observe using direct absorption spectroscopy especially in the near-infrared region. Cavity ring-down spectroscopy is a promising absorption spectroscopy technique which has been widely applied to linear and saturated single-photon absorption spectra. In the present study, we report the observation of a possible two-photon absorption in the near-infrared using cavity ring-down spectroscopy, namely a two-photon resonance of methane. Using an optical frequency comb, the single-photon wavenumber of the double-quantum transition has been determined to be 182 207 682.645 MHz with a standard deviation of 75 kHz.

18 pags., 15 figs., 16 tabs., We report new developments in instrumentation and techniques for both acoustic (speed of sound) and radiometric primary thermometry methods. These include both new cylindrical resonators for extending acoustic gas thermometry to higher temperatures and absolute radiation thermometers incorporating InGaAs detectors to extend primary radiometry to lower temperatures than can be achieved using Si-detector based instruments. These new approaches have been established in order to determine the difference between thermodynamic temperature, T, and the International Temperature Scale of 1990 (the ITS-90), T90, over the temperature range from 430 K to 1358 K as part of the three-year EMPIR project `Implementing the new kelvin 2¿ (InK2). This paper describes the facilities and measurement methodologies for measuring T¿T90 at each of the different institutes, along with an assessment of the target uncertainties. The work is ongoing, but we anticipate that the results of these measurements will ultimately be pooled to provide consensus values of T¿T90 with associated estimated uncertainties. These consensus values will initially feed into the technical annex of the mise en pratique for the definition of the kelvin (MeP-K-19) and, if required, will be used to help to provide a foundation for any future temperature scale., This work has received funding from the EMPIR programme co-financed by the Participating States and from the European Union’s Horizon 2020 R&I programme through the InK2 project. NIM’s research was supported by the National Key R&D Program of China (number 2016YFF0200101)

The performances of a multi-spectral fit for the spectra of pressure-broadened overlapping lines (R9F1, R9F2) of 12CH4 in binary mixtures with N2 were studied by applying different lineshape models, from the simplest Voigt profile (VP) to the Harmann-Tran profile (HTP). Line-mixing was approximated in the first order in the spectral fits. Data were acquired using a high-resolution cavity ring-down spectrometer of minimum detectable absorption coefficient of 2.8 × 10−12 cm−1. The lines were observed with a signal-to-noise ratio of 19 365 for pressures from 5 to 40 kPa. The study reveals that the multi-spectral fits using the HTP and the speed-dependent Nelkin–Ghatak profile (SDNGP) yield the best among all tested. The two models gave the maximum relative residuals of less than 0.065 %. All things considered, the HTP and the SDNGP appear to be the most reliable models for treating the present case of multi-spectral fitting of unresolved dual-component spectra.

CCUS technology has the potential to reduce emissions substantially from the whole lifecycle of traditional energy-intensive industry on a large-scale basis. A summary of the current status of CCUS in China is viewed as a necessary background and a starting point for the content of the following paper. Next, the positioning and analysis of China’s future CCUS development are presented by answering the following questions “Why does China need CO2 utilization?” and “How much of the CO2 emission reductions which result from CCUS technology does China need to be responsible for?”. Then, the important influential factors of China's CCUS development are summarized into three aspects (technology maturity, technology sustainability, and external impact factors). Finally, based on these findings, some important comments and suggestions are proposed for the future RD&D of CCUS technology in China.

A spectral line list for methane in the 6075.3–6078 cm−1 region with the intensity cutoff of 1 × 10−26 cm/molecule at 296 K is presented. We have accurately measured 96 line positions by using cavity ring-down spectroscopy with temperature-controlled cavity. The accuracy of most line positions exceeds that of previous studies. The improvement is due mainly to the accurate line positions obtained from recording high-resolution saturated absorption (Lamb-dip) spectra.

We present the first results for resolving methane (CH_{4}) line transition frequencies down to the kilohertz level for overlapping lines using comb-linked cavity ring-down spectroscopy, while most available laboratory measurements, having resolution at the megahertz level, cannot separate merged lines. To demonstrate the technique, Lamb-dip spectra and linear-absorption spectra were used to identify overlapped lines of vibration-rotation spectra in the R9 multiplet of the 2v_{3} band. Three new weak lines were found for the first time. The experimental methods are extensible to other important bands of CH_{4} and many other gas-phase molecules, and should provide a more detailed understanding of molecular structure and line parameters for future high-precision studies.

We report a new determination of the Boltzmann constant kB using a cylindrical acoustic gas thermometer. We determined the length of the copper cavity from measurements of its microwave resonance frequencies. This contrasts with our previous work (Zhang et al 2011 Int. J. Thermophys. 32 1297, Lin et al 2013 Metrologia 50 417, Feng et al 2015 Metrologia 52 S343) that determined the length of a different cavity using two-color optical interferometry. In this new study, the half-widths of the acoustic resonances are closer to their theoretical values than in our previous work. Despite significant changes in resonator design and the way in which the cylinder length is determined, the value of kB is substantially unchanged. We combined this result with our four previous results to calculate a global weighted mean of our kB determinations. The calculation follows CODATA’s method (Mohr and Taylor 2000 Rev. Mod. Phys. 72 351) for obtaining the weighted mean value of kB that accounts for the correlations among the measured quantities in this work and in our four previous determinations of kB. The weighted mean k̂B is 1.380 6484(28) × 10−23 J K−1 with the relative standard uncertainty of 2.0 × 10−6. The corresponding value of the universal gas constant is 8.314 459(17) J K−1 mol−1 with the relative standard uncertainty of 2.0 × 10−6.

International audience; The International Committee for Weights and Measures (CIPM), at its meeting in October 2017, followed the recommendation of the Consultative Committee for Units (CCU) on the redefinition of the kilogram, ampere, kelvin and mole. For the redefinition of the kelvin, the Boltzmann constant will be fixed with the numerical value 1.380 649 × 10−23 J K−1. The relative standard uncertainty to be transferred to the thermodynamic temperature value of the triple point of water will be 3.7 × 10−7, corresponding to an uncertainty in temperature of 0.10 mK, sufficiently low for all practical purposes. With the redefinition of the kelvin, the broad research activities of the temperature community on the determination of the Boltzmann constant have been very successfully completed. In the following, a review of the determinations of the Boltzmann constant k, important for the new definition of the kelvin and performed in the last decade, is given.

We determined accurate values of ratios among the average molar masses MAr of 9 argon samples using two completely-independent techniques: (1) mass spectrometry and (2) measured ratios of acoustic resonance frequencies. The two techniques yielded mutually consistent ratios (RMS deviation of 0.16 × 10−6 MAr from the expected correlation) for the 9 samples of highly-purified, commercially-purchased argon with values of MAr spanning a range of 2 × 10−6 MAr. Among the 9 argon samples, two were traceable to recent, accurate, argon-based measurements of the Boltzmann constant kB using primary acoustic gas thermometers (AGT). Additionally we determined our absolute values of MAr traceable to two, completely-independent, isotopic-reference standards; one standard was prepared gravimetrically at KRISS in 2006; the other standard was isotopically-enriched 40Ar that was used during NIST's 1988 measurement of kB and was sent to NIM for this research. The absolute values of MAr determined using the KRISS standard have the relative standard uncertainty ur(MAr) = 0.70 × 10−6 (Uncertainties here are one standard uncertainty.); they agree with values of MAr determined at NIM using an AGT within the uncertainty of the comparison ur(MAr) = 0.93 × 10−6. If our measurements of MAr are accepted, the difference between two, recent, argon-based, AGT measurements of kB decreases from (2.77 ± 1.43) × 10−6 kB to (0.16 ± 1.28) × 10−6 kB. This decrease enables the calculation of a meaningful, weighted average value of kB with a uncertainty ur(kB) ≈ 0.6 × 10−6.

We report progress toward determining the Boltzmann constant kB using the concept of a virtual acoustic resonator, a hypothetical resonator that is mathematically equivalent to a cylindrical cavity with periodic boundary conditions. We derived the virtual resonator by combining the measured frequencies of the longitudinal acoustic modes of two argon-filled, cylindrical cavity resonators in such a way to minimize the effects of the cavities' ends, including transducers and ducts attached to the ends. The cavities had lengths of 80 mm and 160 mm and were operated in their longitudinal (l,0,0) modes. We explored virtual resonators that combine modes of the two resonators that have nearly the same frequencies. The virtual resonator formed from the (2,0,0) mode of the 80 mm resonator combined with the (4,0,0) mode of the 160 mm resonator yielded a value for kB that is, fractionally, only (0.2 ± 1.5) × 10−6 larger than the 2010 CODATA-recommended value of kB. (The estimated uncertainty is one standard uncertainty corresponding to a 68% confidence level.) The same virtual resonator yielded values of the pressure derivatives of the speed of sound c in argon, (∂c2/∂p)T and (∂c2/∂p2)T, that differed from literature values by 1% and 2%, respectively. By comparison, when each cavity was considered separately, the values of kB, (∂c2/∂p)T, and (∂c2/∂p2)T differed from literature values by up to 7 ppm, 10%, and 5%, respectively. However, combining the results from the (3,0,0) or (4,0,0) modes of shorter resonator with the results from the (6,0,0) or (8,0,0) modes of the longer resonator yielded incorrect values of kB that varied from run-to-run. We speculate that these puzzling results originated in an unmodeled coupling, either between the two cavities (that resonated at nearly identical resonance frequencies in the same pressure vessel) or between the cavities and modes of the pressure vessel.

Abomasal cannulation, an important research tool in experimental procedures, provides a method for the placement of an abomasal cannula in sheep. The aim of this study was to describe a technique for laparoscopic abomasal cannulation in sheep. It was performed in six anaesthetised sheep positioned in dorsal recumbency using three portals in the abdomen. The first absorbable traction suture was placed 1 cm cranial to the determined abomasal cannula site. A stab incision was made with a laparoscopic monopolar hook electrode in the middle of a purse-string suture placed around the abomasal cannula site. The T-shaped cannula was inserted into the abomasum lumen through the stab incision, and the second traction suture was then placed 1 cm caudal to the abomasal cannula site. The T-shaped abomasal cannula was pulled out of the abdominal cavity through the exit wound located 3–5 cm lateral and 10–12 cm cranial to the right side of the umbilicus. The two traction sutures were tied. The T-shaped cannula was secured to the skin with a finger-trap suture. Repeat laparoscopy was performed 1 month later. Firm adhesion between the abomasum and abdominal wall was observed in all sheep, with no evidence of leakage or peritonitis. No major intraoperative or postoperative complications were encountered. The median surgical time was 49 min, with a range from 42 to 58 min. The abomasal contents were collected easily. In conclusion, laparoscopic abomasal cannulation is safe and easy to perform. Its low complication rates and the “ideal” placement of the tube into the abomasum make it an especially attractive alternative to traditional surgical abomasal cannulation in veterinary practice.

This article describes the accurate determination of the molar mass M of a sample of argon gas used for the determination of the Boltzmann constant. The method of one of the authors (Moldover et al 1988 J. Res. Natl. Bur. Stand. 93 85–144) uses the ratio of the square speed of sound in the gas under analysis and in a reference sample of known molar mass. A sample of argon that was isotopically-enriched in 40Ar was used as the reference, whose unreactive impurities had been independently measured. The results for three gas samples are in good agreement with determinations by gravimetric mass spectrometry; (〈M acoustic/M mass-spec〉 − 1) = (−0.31 ± 0.69) × 10−6, where the indicated uncertainty is one standard deviation that does not account for the uncertainties from the acoustic and mass-spectroscopy references.

We report Raman sideband cooling of a single sodium atom to its three-dimensional motional ground state in an optical tweezer. Despite a large Lamb-Dicke parameter, high initial temperature, and large differential light shifts between the excited state and the ground state, we achieve a ground state population of $93.5(7)$% after $53$ ms of cooling. Our technique includes addressing high-order sidebands, where several motional quanta are removed by a single laser pulse, and fast modulation of the optical tweezer intensity. We demonstrate that Raman sideband cooling to the 3D motional ground state is possible, even without tight confinement and low initial temperature., Comment: 5 pages, 4 figures

In this paper, a two-dimensional discrete element model (DEM) was adopted to predict the creep behaviour of polymer matrix particle reinforced composite PI/SiO2. The polymer matrix was simulated by regularly and closely compacted disks which were bonded together with viscoelastic Burger’s model. The parameters of the Burger’s bond model were derived based on their macroscale material properties. The elastic filler particles with different contents randomly distributed in the models and bonded with the neighbouring matrix disks. Tensile tests of the PI/SiO2 composite with different SiO2 contents under constant loading were performed based on the developed DEM models. The creep strain curves were presented and compared with finite element method (FEM) results. The favourable agreement between the DEM results and the FEM results indicate that the viscoelastic DEM model developed in this study is very capable of simulating constitutive behaviour of PI/SiO2 composites.

Effects of environmental factors on the spatial distribution of five Bupleurum genera were investigated. Eighty seven samples in total in four mountains were collected; 158, 116, 130 and 128 plant species were recorded in Guandi, Wutai, Xiao Wutai and Dongling mountains, respectively. This study has been focused on five particular species (Bupleurum bicaule Helm, Bupleurum scorzonerifolium Willdenow, Bupleurum sibiricum Vest, Bupleurum smithii H.Wolff and Bupleurum chinense DC) not only because of their medicinal properties, but also because of the threat they are subject to. Relations between environmental variables and their influence on these species distribution were analyzed using CANOCO software correlation statistical analysis. The distribution of these five species was found to be differently influenced by environmental variables. However altitude and vegetation type appeared to be the variables which influenced the most Bupleurum distribution in the four surveyed mountains. Preservation of these areas from human disturbance or nevertheless activity controlled by the establishment and strengthening of protected areas could be a solution for a sustainable management. Key words: Bupleurum bicaule, Bupleurum scorzonerifolium, Bupleurum sibiricum, Bupleurum smithii, Bupleurum chinense, environmental variable, canonical correspondence analysis (CCA) multiple species response curves.

In order to measure the distance between our vehicle and the target vehicle by monocular vision and eliminate the estimation error bring by changing of vehicle pose, we propose the distance estimation method based on the vehicle pose information, which can be used to eliminate the error of distance estimation effectively cause by the change of the pitch angle and roll angle of unmanned vehicle. In addition, the pose information could also help us estimate whether the vehicle is in a slope, thus engage in distance estimation for the vehicles. Several groups of data was collected for the experiments. And the result prove the validity of the algorithm in distance estimation.

An enzootic disease characterized by granulomas in internal organs occurred in cage-farmed large yellow croaker, Larimichthys crocea (Richardson), in April and November 2010, in Ningbo, Zhejiang Province. One bacterial strain, named XSDHY-P, was isolated from the diseased fish and identified by biochemical characterization, fatty acid methyl ester (FAME) analysis and multilocus sequence analysis (MLSA). According to the results obtained from the biochemical tests, FAME analysis and phylogenetic analysis derived from 16S ribosomal RNA, gyrB, oprF, oprI, oprL and rpoD gene sequencing, the bacterial isolate, XSDHY-P, was identified as Pseudomonas plecoglossicida. Moreover, lethal dose, 50% trials were carried out to demonstrate the virulence of XSDHY-P in large yellow croaker when administered at 2.13 9 105 colony-forming units per fish. Visceral granulomas were found in the experimentally infected fish as well as in the naturally infected fish, indicating that P. plecoglossicida is another bacterial pathogen that causes granulomatosis in L. crocea.

We report improvements to our previous (Zhang et al 2011 Int. J. Thermophys. 32 1297) determination of the Boltzmann constant kB using a single 80 mm long cylindrical cavity. In this work, the shape of the gas-filled resonant cavity is closer to that of a perfect cylinder and the thermometry has been improved. We used two different grades of argon, each with measured relative isotopic abundances, and we used two different methods of supporting the resonator. The measurements with each gas and with each configuration were repeated several times for a total of 14 runs. We improved the analysis of the acoustic data by accounting for certain second-order perturbations to the frequencies from the thermo-viscous boundary layer. The weighted average of the data yielded kB = 1.380 6476 × 10−23 J K−1 with a relative standard uncertainty ur(kB) = 3.7 × 10−6. This result differs, fractionally, by (−0.9 ± 3.7) × 10−6 from the value recommended by CODATA in 2010. In this work, the largest component of the relative uncertainty resulted from inconsistent values of kB determined with the various acoustic modes; it is 2.9 × 10−6. In our previous work, this component was 7.6 × 10−6.

Resume Les myocardites aigues et subaigues sont une entite anatomopathologique precise mais leur reconnaissance est souvent difficile car leur expression clinique est multiforme et leur diagnostic de certitude repose sur la preuve histologique d’une inflammation myocardique associee a des lesions de degenerescence et/ou de necrose (Kuhl et al., 1998 [3] ). Souvent, la symptomatologie est celle d’une pericardite aigue dominee par la douleur thoracique constrictive qui simule l’infarctus du myocarde et oblige a recourir a la coronarographie pour redresser le diagnostic, surtout lorsque des facteurs de risque arteriels sont presents (Artigou et al., 1984 [6] , Narula et al., 1993 [7] ). Nous rapportons le cas d’un patient de 61 ans, sans antecedent cardiaque ni facteur de risque cardiovasculaire, qui consulte pour une douleur thoracique atypique prolongee et spontanement resolutive, avec un examen clinique et un ECG normaux. La scintigraphie myocardique d’effort a montre une hypofixation non reversible faisant discuter une sequelle de necrose non transmurale ou un artefact. Devant la decouverte d’une zone d’hypokinesie inferolaterale ventriculaire gauche sur l’echocardiographie, une coronarographie diagnostique a ete realisee et s’est averee normale. L’IRM a permis de diagnostiquer des sequelles anciennes de myocardite.

Impurities represent the most significant source of uncertainty in most metal fixed points used for the realization of the International Temperature Scale of 1990 (ITS-90). There are a number of different methods for quantifying the effect of impurities on the freezing temperature of ITS-90 fixed points, many of which rely on an accurate knowledge of the liquidus slope in the limit of low concentration. A key method of determining the liquidus slope is to measure the freezing temperature of a fixed-point material as it is progressively doped with a known amount of impurity. Recently, a series of measurements of the freezing and melting temperature of ‘slim’ Zn fixed-point cells doped with Ag, Fe, Ni, and Pb were presented. Here, additional measurements of the Zn–X system are presented using Ga as a dopant, and the data (Zn–Ag, Zn–Fe, Zn–Ni, Zn–Pb, and Zn–Ga) have been re-analyzed to demonstrate the use of a fitting method based on Scheil solidification which is applied to both melting and freezing curves. In addition, the utility of the Sum of Individual Estimates method is explored with these systems in the context of a recently enhanced database of liquidus slopes of impurities in Zn in the limit of low concentration.

Relative primary acoustic gas thermometry (AGT) determines the ratios of thermodynamic temperatures from measured ratios of acoustic and microwave resonance frequencies in a gas-filled metal cavity on isotherms of interest. When measured in a cavity with known dimensions, the frequencies of acoustic resonances in a gas determine the speed of sound, which is a known function of the thermodynamic temperature T . Changes in the dimensions of the cavity are measured using the frequencies of the cavity's microwave resonances. We explored techniques and materials for AGT at high temperatures using a cylindrical cavity with remote acoustic transducers. We used gas-filled ducts as acoustic waveguides to transmit sound between the cavity at high temperatures and the acoustic transducers at room temperature. We measured non-degenerate acoustic modes in a cylindrical cavity in the range 295 K< T −6 at 295 K to 5×10 −6 at 797 K. In addition, we measured the frequencies of several transverse magnetic (TM) microwave resonances up to 1000 K in order to track changes in the cavity's length L and radius R . The fractional standard deviation of the values of L deduced from three TM modes increased from 3×10 −6 for T −6 at 1000 K. We observed similar inconsistencies in a previous study.

Hair is a protective appendage on the body that is considered accessory structure of the integument. Hair follicle development takes place during fetal skin development and relies on tightly regulated ectodermal-mesodermal interactions. The morphological changes of the hair cycle have been very clear that hair morphogenesis and epidermal development are orchestrated by an array of growth factors. In this review, we summarize the major growth factors involved in promoting growth of hair follicles.

The length is one of the key parameters for a cylindrical acoustic resonator used for measurement of the Boltzmann constant. A research project has been conducted in the National Institute of Metrology (NIM), China, for the re-determination of the Boltzmann constant with a fixed-path cylindrical acoustic resonator. This paper describes the procedure for the length determination. The excess fraction method was applied to accurately obtain the length of the resonator. This method is performed in a two-step procedure. First, the length is coarsely determined as L1 with an uncertainty of 1.5 μm in the length division of NIM. Second, the result of the coarse measurement is further interpolated by the dual wavelength laser interferometer with a resolution of 1 nm, which is composed of a 633 nm He–Ne laser and a 657 nm semiconductor laser. A Michelson wavemeter has been constructed for calibration of the wavelength of the semiconductor laser. The length variation of the resonator has to be measured from room temperature to the triple point of water (TPW). As a result, the laser interferometer can be also used as a precise dilatometer. The result and the measurement uncertainty of the length measurement are given in this paper.

A single, fixed-path-length cylindrical-cavity resonator was used to measure c0 = (307.825 2 ± 0.001 2) m · s−1, the zero-density limit of the speed of sound in pure argon at the temperature of the triple point of water. Three even and three odd longitudinal modes were used in this measurement. Based on the ratio M/γ0 = (23.968 644 ± 0.000 033) g · mol−1, determined from an impurity and isotopic analysis of the argon used in this measurement and the measured c0, the value kB = 1.380 650 6 × 10−23J · K−1 was obtained for the Boltzmann constant. This value of kB has a relative uncertainty ur(kB) = 7.9 × 10−6 and is fractionally, (0.12 ± 8.1) × 10−6 larger than the value recommended by CODATA in 2006. (The uncertainty is one standard uncertainty.) Several, comparatively large imperfections of our prototype cavity affect the even longitudinal modes more than the odd modes. The models for these imperfections are approximate, but they suggest that an improved cavity will significantly reduce the uncertainty of c0.

This study investigated the effects of a combination of tiletamine-zolazepam and xylazine plus tramadol (TZXT) and compared the efficacy of this combination with that of tiletaminezolazepam and xylazine (TZX) for providing anaesthesia in Chinese experimental miniature pigs. Fourteen healthy, eight-month-old miniature pigs of both sexes were immobilised with TZXT or TZX on two different occasions. The pigs' immobilisation and analgesia scores and baseline physiological parameters (heart rate, respiratory rate, non-invasive systolic, diastolic and mean arterial blood pressures, arterial haemoglobin oxygen saturation and rectal temperature) were determined before and five, 10, 30, 45, 60, 80 and 100 minutes after the administration of TZXT or TZX. Pigs in both groups became laterally recumbent within three minutes. Some physiological parameters were changed after administration of the drug combinations, but they remained within biologically acceptable limits and were not significantly different between the two treatments. The use of TZXT resulted in better induction time and quality of recovery compared with TZX, with higher scores for sedation, analgesia, muscle relaxation, posture and auditory response. The animals were much calmer during recovery after TZXT immobilisation.