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The composition, operating principle, and metrological characteristics of GET 130-2019, the State Primary Special Standard of the unit of length in the field of measurements of deviations from straightness and flatness, are described. Results of investigations of the metrological characteristics of the interference measurement system incorporated into GET 130-2019 by means of which reproduction of the unit is realized on the basis of the fundamental physical constants and the properties of matter (interference) are presented, thus eliminating any additional instrumental sources of errors (uncertainty). Transmission of the unit of length in the region of measurements of deviations from straightness and flatness in the range 0–50 μm with length of the measured surface up to 30 m is achieved with the highest accuracy attainable in Russia. Comparisons that were carried out demonstrate that the metrological characteristics of GET 130-2019 correspond to the level of precision of foreign standards in measurements of deviations from straightness on a length up to 30 m and to the measurement capabilities presented in the database of the International Bureau of Weights and Measures.

Precision interference measurement of parameters of form optical surfaces are one of the most important type of the measurement in the field of the geometrical values. In countries-participants of this comparisons the special primary standards in this field of measurements take part in reproduction and transmission the unit of length in this field of measurements ensuring high measuring and calibrating capabilities countries in this type of measurement. In this article presents the result of supplementary comparisons COOMET 570/UA-a/12. The result of comparisons allowed to declare to Belarus and Russia, and to confirm to Ukraine their measuring and calibrating capability in database CIPM MRA.

Here the debated issue of units of length in building construction practice in ancient Aegean architecture is focused through the case study of the Mycaenean tholos tomb, the Treasury of Atreus. Recent architectural analysis of the monument highlights a geometric mesh underlying its architectural form, which reveals the coexistence of more than one unit of length and the geometric relations among them. These units are consistent with the modular units reported in the literature. Starting from such details, the present study explores the usefulness of the identified mesh for measuring lengths and areas in situ and controlling the construction process. The integrated analysis of length measurement systems and the associated geometric pattern shed light on their strict correlation. The contextualization of the units of length in their systems in multiples and sub-multiples and the aim to compute lengths explain and clarify the co-existence of diverse modular units in Aegean architecture.

GET 183–2019, the State Primary Special Standard of the unit of length in the area of measurements of the parameters of deviations from flatness of optical surfaces, is presented. The standard supports the reproduction, storage, and transmission of the unit of length in the range 0.002–2.000 μm for optical surfaces measuring 50–280 mm in dimension. An interference apparatus incorporated into GET 183–2019 in which a new method of treatment and interpretation of interference patterns is described, the method of phase steps, is implemented. Studies conducted as part of an effort at improving the standard, including theoretical and experimental investigations of the interference apparatus, are described. The selection of the new method is evaluated and a comparative analysis of the calibration and measurement capabilities of foreign metrological devices is performed. The metrological characteristics of GET 183–2019 are presented.

We developed an automated system for navigating photonic chips through layout for automatic testing as well as assisted troubleshooting. The system was built to allow, in addition to standard grating-coupling measurements, top-scattering measurement along the waveguide structures for characterization of the devices/materials for each platform layout and estimate the optical loss per unit of length, making it to improve the next generation of devices. Micrometer resolution mapping along the digitized path of the waveguide was achieved, enabling video monitoring of scattering events and changes in the intensity map.

The residual vibration of steel rail is rich in the mechanical properties, which include the constraint, that was, the degree of tightness of the fastener. The aim of this research is to characterize the tightness of rail fastener. A fractal analysis procedure based on 1-D curve length calculation is proposed, which applies a length unit to cover fastening the behavior of fasteners. Using the rail vibration data under periodic pulse excitation measured by a track fastener inspection vehicle, this method can derive the fractal dimension of fastener tightness directly (D∈ [1, 2)). Furthermore, 1-D curve length method is also introduced into multi-fractal spectrum analysis for investigating fine scale information. The statistical analysis demonstrates that, fractal dimension Dl, Dr, and multi-fractal parameters αfmax, ∆α can reflect the change process of the tightness of rail fasteners effectively. Therefore, it shows potential to use the fractal parameters of the rail vibration signal to characterize the tightness of the fastener.

The tolerances for the alignment of the magnets on the girders of the proposed particle accelerator of the Brazilian Synchrotron Light Laboratory (LNLS), Sirius, are as small as 40 μm for translations and 0.3 mrad for rotations. The functional axis of the magnets is measured by the vibrating wire technique, which employs conductive wires of diameters of approx. 0.1 mm. Since the alignment has to be performed targeting these magnetic axes, rather than their geometric centrelines, non-contact measuring sensors mounted on a coordinate measuring machine have been chosen to measure the relative deviations between magnets. To better the measurement accuracy for that specific measuring task, to allow interim checks on multiple coordinate measuring systems, and to provide effective traceability to the SI unit of length, a multipurpose geometrical artefact has been devised. The reasoning behind this development and the first measurement results are described in this paper.

Achieving a uniform welding seam with minimum overheating is crucial to obtain high quality joints in laser welding. The classical formula of the overlapping factor for laser pulsed welding was modified by the introduction of empirical corrections from the application of static pulses involving constant energy combinations of laser power and pulse duration. The energy re-allocation in the case of dynamic pulses was studied as a function of the laser displacement speed. Energy optimization criteria aiming the minimization of the energy per length unit or surface unit were introduced. An optimized uniform welding seam with minimum thermal affectation was obtained by means of dynamic pulses.

The use of the thermal imaging method for active nondestructive evaluation of subsurface defects of articles is examined. The scale factors for converting the values of defect size from pixels to length units are estimated. The effect of size and depth of a defect on the distribution of heat along the surface is analyzed.

Suppose that a destroyed network needs to be restored by a number of servers (construction crews) that are initially located at some nodes of the network (depots). Each server can restore one unit of length of the network per unit of time. When several servers are simultaneously working at the same point, their restoration speeds combine additively. The servers can travel within the already restored part of the network with infinite speed, which means that travel times are negligible with respect to construction times. It is required to minimize the time when each node becomes connected to at least one of the depots. We show that the problem is strongly NP-hard on general networks, and present fast polynomial algorithms for trees and cactus networks which are connected networks where each node and each edge belong to at most one cycle. © 2017 Wiley Periodicals, Inc. NETWORKS, Vol. 70(1), 60–68 2017

The certified reference material BAM-L200, a nanoscale stripe pattern for length calibration and specification of lateral resolution, is described. BAM-L200 is prepared from a cross-sectioned epitaxially grown layer stack of AlxGa1-xAs and InxGa1 xAs on a GaAs substrate. The surface of BAM-L200 provides a flat pattern with stripe widths ranging down to 1 nm. Calibration distances, grating periods and stripe widths have been certified by TEM with traceability to the length unit. The combination of gratings, isolated narrow stripes and sharp edges of wide stripes offers a plenty of options for the determination of lateral resolution, sharpness and calibration of length scale at selected settings of imaging surface analytical instruments. The feasibility of the reference material for an analysis of the lateral resolution is demonstrated in detail by evaluation of ToF-SIMS, AES and EDX images. Other applications developed in the community are summarized, too. BAM-L200 fully supports the implementation of the revised International Standard ISO 18516 (in preparation) which is based on knowledge outlined in the Technical Report ISO/TR 19319:2013.

The article presents the results of an experimental study of coaxial and orthogonal methods for comparing laser measuring interferometric systems using a standard measuring complex of length from the State Primary Special Standard of a Unit of Length in the range from 2 to 60 m. transmission errors of the unit of length up to 0.5 microns.

Background: The redefinition of a unit of length - a meter - through a unit of time and a fundamental constant - the speed of light in vacuum - has opened up the fundamental possibility of a significant reduction in the uncertainty of its reproduction. Now progress in areas such as absolute ballistic gravimetry, control of large-sized aspherical optics, laser interferometry, and the production of electronic components in the semiconductor industry have made this feature extremely relevant. It is known that the measuring scale of laser interferometers used for precision distance measurement is non-linear, since the common-mode surfaces of any real radiation beam are located irregularly in space. To compensate for the effect of this irregularity on the measurement result, it is necessary to know the precision phase structure of real laser beams. Objectives of the work is comparing existing methods for studying the phase structure of optical radiation beams and estimating the distribution of the topological phase shift of a relatively uniform plane wave. Materials and methods:. The well-known theoretical methods for calculating the topological phase shift of in-phase surfaces of an optical beam are considered and compared - the Lommel-Debye method based on the Fresnel-Kirchhoff integral, the modified method based on the Rayleigh-Sommerfeld integral and the Gaussian beam method based on a parabolic equation. Results: Each method performed calculations of the accumulated phase lag of the focused radiation beam when moving the observation plane relative to the focal point. The distribution of the relative change in the distance between the in-phase surfaces in the range of displacements from λ to 106•λ was also calculated. The most adequate physical picture of the phenomenon was obtained by the Gaussian beam method based on a parabolic equation. Conclusion: The results will be used to reduce the systematic error of laser interferometers.

The report is about investigations of metrological characteristics of iodine-stabilize He-Ne laser by The State Primary Standard.

Summary Selection of a suitable robotic manipulator, out of the available conventional configurations, is one way to employ a robot. However, with the increasing applications of robotic assistance, the concept of task-oriented customised design for prescribed working locations in a given environment, has got attention of several researchers. One of the challenges in this direction is the realisation of specific designs, involving unconventional values of robotic parameters. This paper discusses the D–H parameters based adaptive modules, which can be adjusted according to the given values of robotic parameters. The modules are available in three types with similar architecture. The details of this basic length unit, adaptive twist unit and extended length unit are discussed. Focus of the work is to validate the adaptability of the proposed architecture through the modelling, simulation and development of standard configuration.

The metrological characteristics of modern high-precision laser measurement systems and instruments for the measurement of the level of petroleum and petroleum products used in commercial accounting are presented. Results of studies of the components of the nonexcluded systematic and random errors, the standard deviation, and confidence limits of the total error of the transmission of the unit of length by a 30-m laser interference comparator incorporated into the structure of the state primary standard of the unit of length, the meter, are presented.

This paper investigates the mechanical response of a modular head-neck interface of hip joint implants under realistic loads of level walking. The realistic loads of the walking activity consist of three dimensional gait forces and the associated frictional moments. These forces and moments were extracted for a 32mm metal-on-metal bearing couple. A previously reported geometry of a modular CoCr/CoCr head-neck interface with a proximal contact was used for this investigation. An explicit finite element analysis was performed to investigate the interface mechanical responses. To study the level of contribution and also the effect of superposition of the load components, three different scenarios of loading were studied: gait forces only, frictional moments only, and combined gait forces and frictional moments. Stress field, micro-motions, shear stresses and fretting work at the contacting nodes of the interface were analysed. Gait forces only were found to significantly influence the mechanical environment of the head-neck interface by temporarily extending the contacting area (8.43% of initially non-contacting surface nodes temporarily came into contact), and therefore changing the stress field and resultant micro-motions during the gait cycle. The frictional moments only did not cause considerable changes in the mechanical response of the interface (only 0.27% of the non-contacting surface nodes temporarily came into contact). However, when superposed with the gait forces, the mechanical response of the interface, particularly micro-motions and fretting work, changed compared to the forces only case. The normal contact stresses and micro-motions obtained from this realistic load-controlled study were typically in the range of 0-275MPa and 0-38µm, respectively. These ranges were found comparable to previous experimental displacement-controlled pin/cylinder-on-disk fretting corrosion studies.

The appearance of the frequency comb technology, awarded the Nobel Prize in Physics 2005, has enormously revolutionized the metrology of optical frequencies, eliminating the need for complicated frequency chains. By direct linking to the unit of time, the second, through frequency standards (Cs , Rb ), by using femtosecond mode-locked lasers and frequency comb technology, the Spanish Centre of Metrology (CEM) has established a new way of practical realisation of the National Standard of Length, the metre. By stabilising and characterising two free parameters – the repetition frequency fr and the offset frequency f 0 , the frequency comb generator thereby was successfully put into operation. After such realization, the accuracy of the length unit will be increased in two orders of magnitude, that is 2 × 10−13 instead of 2.1 × 10−11 . In this paper we present the results of applying comb generator to the absolute measurement of the three Zeeman stabilized He–Ne lasers operating at 633 nm with a nominal frequency of 473.612 THz. A comparison of these results with those obtained by the current system based on standard iodine stabilized lasers is in good compatibility. A treatment for the evaluation of measurement uncertainty of laser frequency in calibration using a comb in accordance with Guide of Uncertainty Measurement ISO/BIPM is also presented.

All measurements performed in science and industry are based on the International System of Units, the SI. It has been proposed to revise the SI following an approach which was implemented for the redefinition of the unit of length, the metre, namely to define the SI units by fixing the numerical values of so-called defining constants, including c, h, e, k and N(A). We will discuss the reasoning behind the revision, which will likely be put into force in 2018. Precision engineering was crucial to achieve the required small measurement uncertainties and agreement of measurement results for the defining constants.

The word “Nano” in a part of the title of the present book is an abbreviation of nanometer (nm), which is the unit of length with a prefix in the International Standard of Unit (SI).

The absolute measurement of g is currently realized through the laser interferometric measurement of a free falling retro-reflector. The Micro-g LaCoste FG5X is a free-fall gravimeter with a laser interferometer in Mach-Zehnder configuration which uses simultaneous time and distance measurements to calculate the absolute value of g. Because the instrument itself contains the necessary working standards for precise time and length measurements, it is considered independent of external references. The timing is kept with a 10 MHz rubidium oscillator with a stability of 5×10e−10 . The length unit is realized by the laser interferometer. The frequency calibrated and iodine stabilized helium-neon laser has a wavelength of 633 nm and an accuracy of 2.5×10e−11. In 2012 the FG5-220 of the Institut für Erdmessung (IfE) was upgraded to the FG5X-220. The upgrade included a new dropping chamber with a longer free fall and new electronics including a new rubidium oscillator. The metrological traceability to measurement units of the Système International d’unités (SI unit) is ensured by two complementary and successive approaches: the comparison of frequencies with standards of higher order and the comparison of the measured g to a reference measured by absolute gravimeters defined as primary standards within the SI. A number of experiments to test the rubidium oscillator were performed. The oscillator showed a linear drift of 0.2×10e−3 Hz per month (=0.3 nm/s² per month) in the first 18 months of use. A jump in the frequency of 0.01 Hz (=20 nm/s² ) was revealed recently and the drift rate changed to −0.5×10e−3 Hz /month.

A prototype standard sample GSO 10030-2011 for the stepped parameters of thin layers of single crystal silicon is developed and certified. It is intended for calibration of transmission electron microscopes at magnifications of 1000–1,500,000×. The certified parameters are the step size of the stepped structure and the distance between the (111) planes of the single crystal silicon in this material. Both parameters are independently traceable to the unit of length, the meter.

The unit of length from the primary standard to the nanometer range is not transmitted yet. Good measuring device stability for precision measurements in this area is needed. None of the lasers can be compared with the gas discharge one in characteristics of stability and coherence. There is gain on shape dependence in the active element of such lasers. This article describes the calculation methods and ways of gain increasing, which help to reduce the device size and improve the passive stability.

Humans have remarkable statistical learning abilities for verbal speech-like materials and for nonverbal music-like materials. Statistical learning has been shown with artificial languages (AL) that consist of the concatenation of nonsense word-like units into a continuous stream. These ALs contain no cues to unit boundaries other than the transitional probabilities between events, which are high within a unit and low between units. Most AL studies have used units of regular lengths. In the present study, the ALs were based on the same statistical structures but differed in unit length regularity (i.e., whether they were made out of units of regular vs. irregular lengths) and in materials (i.e., syllables vs. musical timbres), to allow us to investigate the influence of unit length regularity on domain-general statistical learning. In addition to better performance for verbal than for nonverbal materials, the findings revealed an effect of unit length regularity, with better performance for languages with regular- (vs. irregular-) length units. This unit length regularity effect suggests the influence of dynamic attentional processes (as proposed by the dynamic attending theory; Large & Jones (Psychological Review 106: 119–159, 1999)) on domain-general statistical learning.

A brief review of the measurement capabilities of the leading national metrological institutes of the world in the field of measurements of ruled length gauges (tape measures) is given. A comparative analysis of the construction of comparators is carried out. The thirty-meter laser interference comparator, which forms part of the State Primary Standard of the unit of length (the GET 2-2010 meter), is described. Ways of further improvement and new areas of application, e.g. checking scanners, trackers, level meters, optical range finders and other measuring instruments, are indicated.

Registration, also known as pose estimation and position registration, is an essential part of the accurate quantitative analysis of velocity data obtained with a scanning laser Doppler vibrometer (SLDV). This paper presents a hybrid method of registration using a general linear laser model. The general linear laser model uses sets of slopes and intercepts rather than nonlinear functions of mirror angles to describe the spatial path of the laser beam. This simplifies registration mathematics and also allows the hybrid registration algorithm to be applied to any type of SLDV using any length unit system. The hybrid registration algorithm is comparable in accuracy to existing methods, but eliminates the need for laser rangefinders and the generation of high quality starting points in optimization. This is accomplished by using a very stable optimization based on distance between point pairs to generate a large number of potential solutions from random starting guesses, and then selecting the correct solution by means of a secondary error descriptor. Simulated and experimental validation is presented to support the effectiveness of this algorithm.

Calculation methods of spur and helical gear drives for preliminary designs or standardization purposes available in technical literature, use the Hertz equation to evaluate the contact stress, assuming the load to be uniformly distributed along the line of contact. However, this model presents some discrepancies with experimental results because the changing rigidity of the pair of teeth along the path of contact produces a non-uniform load distribution, which implies that some load distribution factors are required to compute the contact stress. In this paper, a non-uniform model of load distribution along the line of contact, recently developed, obtained from the minimum elastic potential criterion, has been used. This model combined with the Hertz equation yields more accurate values of the contact stress. As the load per unit of length at any point of the line of contact and any position of the meshing cycle has been described by a very simple analytic equation, a complete study of the location and value of the critical contact stress has been carried out. From this study, a recommendation for the calculation of the pitting load capacity of spur and helical gears is proposed.

In this paper we report the recent progresses on the time and frequency primary standards at the National Institute of Metrology (NIM) China: stabilized lasers for practical realization of the length unit (meter) of the International System of Units (SI); the cesium fountain clocks to realize the SI time unit (second) with an uncertainty of 2×10-15; the femto-second optical frequency combs, establishing the coherent connection between microwave frequency and optical frequency, to calibrate the optical wavelengths traceably to the microwave standard frequency with uncertainty better than 4×10-14; and the construction of a Sr lattice optical clock as a candidate of possible future redefinition of the second. We also describe: (1) fs optical combs are serve-locking systems and the specification to characterize their performance should be their tracking precision; (2) the estimated uncertainty limitations of sample cell - atom beam - cold atom fountain - trapped atom/ion frequency reference techniques.

Line-start incremental centrifugal liquid sedimentation (disc-CLS) is a powerful technique to determine particle size based on the principles of Stokes&rsquo, law. As most input quantities of the Stokes equation cannot be easily determined for typical instruments used for this method, an alternative method which depends on calibrating the sedimentation time scale with reference particles has become common practice. Unfortunately, most of these calibration materials (calibrants) come with limited information regarding their metrological reliability (e.g., lack of measurement uncertainties and traceability statements, incomplete measurand definitions). As a consequence, routine particle size results obtained by disc-CLS are mostly only traceable to the calibrant used, and effective comparisons can only be made for those results originating from measurements performed with the same types of calibrants. In this study, we discuss the concept of metrological traceability and demonstrate that particle size results obtained by disc-CLS can be traceable to the ultimate metrological reference, i.e., the unit of length in the International System of Units (SI), the meter. Using the example of two colloidal silica certified reference materials, we describe how laboratories can realize metrological traceability to the SI by simplifying complex traceability networks.

The paper gives a survey of the upcoming use of X-ray computed tomography (CT) for dimensional quality control purposes: i.e. for traceable measurement of dimensions of technical (mechanical) components and for tolerance verification of such components. It describes the basic principles of CT metrology, putting emphasis on issues as accuracy, traceability to the unit of length (the meter) and measurement uncertainty. It provides a state of the art (anno 2011) and application examples, showing the aptitude of CT metrology to: (i) check internal dimensions that cannot be measured using traditional coordinate measuring machines and (ii) combine dimensional quality control with material quality control in one single quality inspection run.

At the IX Session of the Commission of Length in September 1997, the values of the frequency and wavelength of He?Ne laser emission, stabilized by a saturated absorption line in molecular iodine, ? = 473?612?214?705 kHz, ? = 632.991?398?22 nm, were recommended. The emission of such lasers is used all over the world as a material bearer of a length unit. In Russia, reproduction and transmission of its size is realized with the help of a reference interferometric device, an atomic force microscope of original design, where displacement along the X, Y and Z axes is controlled by a laser interferometric nanodisplacement measuring device. By this means, scanning in all three coordinates is measured in fractions of laser emission wavelength, which in its turn serves as a material unit length bearer. In practice, linear measurements in the nanometre range are carried out with scanning electron (SEM) and scanning probe (SPM) microscopes. A standard of the width of the line and of the pitch, called 'MShPS-2.0K', is used in Russia. This standard enables us to determine the SEM magnification, as well as the effective diameter of its electron probe. Moreover, one can determine the SPM scale factor for the three scanning axes, the Z-scanner nonorthogonality and the effective radius of the SPM cantilever tip by means of the standard MShPS-2.0K (Russian abbreviation). The authors describe in the present paper the methods for the linear measurements in the nanometre range with the use of the SEM and SPM. These methods were proposed by Russian specialists, and have been employed at Russian research institutes as well as at Russian manufacturing enterprises.

A new kind of high resolution, high accuracy comparator for dimensional measurements and its application for the measurement of the thickness of gauge blocks is presented. This comparator consists of two scanning tunnelling microscopes (STMs) whose tips probe the opposite sides of a sample. The STM tips are fixed on two high quality mirrors that are moved by piezoelectric actuators. The positions of the mirrors are measured by a high resolution laser interferometer, thereby coupling the length measurements to the unit of length. The detection of the sample's surface is performed by the STM probes and utilizes the high dependence of the tunnelling current on the tip-to-sample distance, which follows an exponential function and reaches about 1 nA at a tip-to-sample distance of less than 1 nm. This technique allows one to determine the position of the surface with a higher degree of accuracy than is possible using mechanical or optical probes. The determination of a distance consists of two consecutive displacement measurements by laser interferometer without and with the sample between the two tunnelling tips. The difference of these measurements corresponds to the object's length once environmental conditions such as temperature and refractivity are taken into account. In this paper we describe the construction and alignment of the instrument, the optimization of various components and experimental investigations of some parts of the measuring process, show first experimental results of the complete comparator obtained on thin gauge blocks and discuss the uncertainty budget.

GLONASS could hardly reach the positioning performance of GPS, especially for fast and real-time precise positioning. One of the reasons is the phase inter-frequency bias (IFB) at the receiver end prevents its integer ambiguity resolution. A number of studies were carried out to achieve the integer ambiguity resolution for GLONASS. Based on some of the revealed IFB characteristics, for instance IFB is a linear function of the received carrier frequency and L1 and L2 have the same IFB in unit of length, most of recent methods recommend estimating the IFB rate together with ambiguities. However, since the two sets of parameters are highly correlated, as demonstrated in previous studies, observations over several hours up to 1 day are needed even with simultaneous GPS observations to obtain a reasonable solution. Obviously, these approaches cannot be applied for real-time positioning. Actually, it can be demonstrated that GLONASS ambiguity resolution should also be available even for a single epoch if the IFB rate is precisely known. In addition, the closer the IFB rate value is to its true value, the larger the fixing RATIO will be. Based on this fact, in this paper, a new approach is developed to estimate the IFB rate by means of particle filtering with the likelihood function derived from RATIO. This approach is evaluated with several sets of experimental data. For both static and kinematic cases, the results show that IFB rates could be estimated precisely just with GLONASS data of a few epochs depending on the baseline length. The time cost with a normal PC can be controlled around 1 s and can be further reduced. With the estimated IFB rate, integer ambiguity resolution is available immediately and as a consequence, the positioning accuracy is improved significantly to the level of GPS fixed solution. Thus the new approach enables real-time precise applications of GLONASS.

This paper describes the characteristics of a two-color method based on the adjacent pulse repetition interval length (APRIL), which functions as a length unit for femtosecond optical frequency combs (FOFCs), and compares the results to the wavelength-based two-color method. The wavelength-based two-color method can eliminate the inhomogeneous disturbance of effects caused by the phase refractive index; therefore, the APRIL-based two-color method can eliminate the air turbulence of errors induced by the group refractive index. Our numerical analysis of the APRIL-based two-color method will contribute to the pulse-laser-based two-color method, which secures traceability to the definition of the meter via APRIL.

The certified reference material BAM-L200, a nanoscale stripe pattern for length calibration and specification of lateral resolution, is described. BAM-L200 is prepared from a cross-sectioned epitaxially grown layer stack of AlxGa1−xAs and InxGa1−xAs on a GaAs substrate. The surface of BAM-L200 provides a flat pattern with stripe widths ranging down to 1 nm. Calibration distances, grating periods and stripe widths have been certified by TEM with traceability to the length unit. The combination of gratings, isolated narrow stripes and sharp edges of wide stripes offers plenty of options for the determination of lateral resolution, sharpness and calibration of length scale at selected settings of imaging surface-analytical instruments. The feasibility of the reference material for an analysis of the lateral resolution is demonstrated in detail by evaluation of ToF-SIMS, AES and EDX images. Other applications developed in the community are summarized, too. BAM-L200 fully supports the implementation of the revised International Standard ISO 18516 (in preparation) which is based on knowledge outlined in the Technical Report ISO/TR 19319:2013.

Line and screw systems, used in robotics and machinery analysis, become singular at particular geometric configurations. When not singular, measures are required that describe how far they are from being so. A new system of measures is proposed whose outcome is strictly invariant with respect to coordinate frame, origin and unit of length. Examples of the application of the new measures to sixfold systems of lines and screws in the context of work-holding systems and robotic manipulators are given.

Metrological Problems during Hardness Measurements of thin layers. The essential calibration problem at indentation measurements in the micro and nano range, the determination of the tip geometry of the indenter, can be solved with a modified SFM which allows coordinate measurements with traceability to the length unit. A comparison of the area functions which were determined with an SFM and a reference material showed a sufficiently good agreement. For the remaining quantities of the indentation test influencing the uncertainty of measurement practicable calibration methods are existing. New challenges to the development of calibration methods for indentation testers puts the nano range which for the assessment of mechanical properties of layers with a thickness in the nanometer range gains increasing importance.

X-ray interferometry is a crystallographic diffraction technique utilizing a moire effect generated by the lattice. If almost perfect silicon single crystals are employed, scanning of the periodic moire can be used for the calibration of translation or rotation on a nanometric scale since the lattice parameter is well known in terms of the SI unit of length. A monolithic x-ray angle interferometer consisting of two crystal blocks and a connecting flexure spring allowing relative rotation was manufactured. Each block supports two x-ray optical lamellae. Their optimum thickness for good visibility of the angular moire fringes during rotation was calculated using the dynamical theory of x-ray diffraction. The main block serves as the base of the interferometer and also incorporates the piezoelectric drive. This arrangement of three bimorph actuator blades allows angular scanning through the zero degree position in order to use the full Bragg reflection width. Pre-tensioning of the flexure spring, balancing of the rotating part and angular scanning are possible simultaneously. Different operating modes, free-running and locked to the fringe slope, were tested. This very compact device can be used as a stand-alone instrument or as a fine scale in a large angle measuring calibrating facility.

Earthquakes can irreversibly damage nuclear power plants especially in the core. Engineers need special tools to insure that the core will resist the worst conditions. Most of the models developed for industrial purpose account for the damping and added mass induced by the axial flow, and need to identify the related coefficients. Therefore, experiments on full scale fuel assemblies need to be performed. The LHC (Laboratory of Core and Circuit Hydrodynamics) has facilities to perform dynamical tests under axial flow of a fuel assembly. The displacement of one grid of the fuel assembly is imposed by a hydraulic jack with a force sensor, and the displacements of the other grids are measured. LDV measurements are also performed to give a description of the flow distribution in the fuel assembly. An identification based on a Proper Orthogonal Decomposition is proposed. Co-efficients obtained are given by unit of length, which means that they are directly available for models.Copyright © 2013 by ASME

Measurements carried out on a laser multiplication chain at the All-Russia Scientific-Research Institute of Physicotechnical and Radio Engineering Measurements made it possible to improve the precision of determination of the frequencies of laser standards recommended for reproducing the unit of length. This investigation showed that the long-term drift of the dimensionless combination of the atomic constants g1α2(me/mp)1/2 did not exceed 10-12 per year (g1 is the gyromagnetic ratio of the proton, α is the fine-structure constant, and me and mp are the masses of an electron and a proton).

State-of-the-art interconnect design is very challenging. Designers are facing ever more stringent design specifications expressed in terms of bandwidth, speed, crosstalk, signal attenuation, etc. that dictate the need for powerful modeling tools. It is of a paramount importance that these tools are able to very accurately incorporate all substrate loss mechanisms and the finite conductivity and shape of the metallic interconnects. From this perspective, macromodels describing all high-frequency behavior are extremely useful to analyze the signal integrity (SI) behavior of the interconnects. Often, interconnect structures are characterized by using their cross-sectional geometry in a two-dimensional (2-D) electromagnetic (EM) simulation, leading up to a corresponding transmission line model [1]. An accurate description of the interconnects is then provided in terms of their per unit of length (p.u.1.) resistance (R), inductance (L), conductance (G) and capacitance (C) parameters, yielding so-called RLGC(f) models. Here, f denotes the frequency, as such indicating the frequency-dependent character of the p.u.l. parameters. For a comprehensive overview of such modeling methods, the reader is encouraged to consult [1] and the references therein. For on-chip lines that are electrically very short, sometimes, the p.u.l. resistance R and capacitance C are dominant (RC regime). In the present paper, however, all four p.u.l. parameters are considered, making the approach more general and also valid at very high frequencies. Thereto, a very accurate 2-D EM modeling procedure, making use of a Dirichlet-to-Neumann (DtN) boundary operator, is used as a starting point [2]. This method

This paper deals with the major factors affecting the resolving power of imaging devices employing pyroelectric radiation detector arrays. These include thermal and electrical crosstalk between discrete elements of the array. The role and effect of the number of sensitive elements per unit of length and dimension of spacing between them on array resolution magnitude have been analysed.

The Optical Metrology Division (Diopt) of Inmetro is responsible for maintaining the national reference of the length unit according to International System of Units (SI) definitions. The length unit is realized by interferometric techniques and is disseminated to the dimensional community through calibrations of gauge blocks. Calibration of large gauge blocks from 100 mm to 1000 mm has been performed by Diopt with a Koesters interferometer with reference to spectral lines of a krypton discharge lamp. Replacement of this lamp by frequency stabilized lasers, traceable now to the time and frequency scale, is described and the first results are reported.

The acquisition of a femtosecond laser comb by the Optical Metrology Division of Inmetro now allows for carrying out high precision calibrations of optical frequencies for lasers which are used as standards of the length unit with gauge block interferometers. The frequency comb is operated as an optical frequency synthesizer and is presently linked to the time unit by a 10 MHz oscillator which is disciplined by GPS. Laser frequencies are determined with accuracy in the range of few parts in 1012. This measurement method now links the length unit, meter, to the SI-second attending the recommendation by the BIPM.

Fractal analysis previously developed for surface characterization is generalized and an intrinsic length unit a in this analysis has been taken as lateral resolution of the measuring instrument η. This generalized analysis allows the surface characterization in terms of two fractal parameters-fractal dimension D and amplitude coefficient C , which, in theory, are instrument independent and unique for each surface . A powerful technique is developed for the simulation of fractal surface profiles. Based on the generation of random surfaces of various D and C values, we note that D primarily relates to relative power of the frequency contents and C to the amplitude of all frequencies. A number of engineering surfaces-particulate magnetic tapes, thin-film rigid disks, steel disks, plastic disks and diamond films, all of varying roughnesses were measured to validate the generalized fractal analysis. We have obtained D and C parameters for each engineering surface from the measurements made using two instruments with significantly different resolutions. The variation in C within each surface is attributed to the simplified assumption of lateral resolution as the intrinsic length unit. We found that for a given surface with varying roughnesses, D essentially remains constant and to a first order C varies monotonically with variance of surface heights ( σ 2 ) for a given instrument. Simulated σ shows similar trends to the measured σ for small scan lengths. Coefficient of friction of all surfaces has reasonable correspondence with C . Based on this study, the fractal parameter C may better represent the variance for tribological surfaces.

Analysis of the results indicates that: a) all the optimal trajectories may be divided into two sections: the phased section, corresponding to motion over a trajectory close to the initial one with a small change in initial energy (amounting to around two-thirds of the total journey time); and the orbital transfer, with considerable change in orbital energy, as a result of active control of the solar-sail orientation (around one-third of the total journey time). In the second section, the spacecraft first moves closer to the Sun and then makes the transfer to Mars orbit; b) the duration of orbital transfer is 581 dyas according to the optimal plan, which includes sections of deceleration and movement from the initial orbit over a distance of 0.2 dimensional length units toward the Sun; with the constraint ϑ