Nanometer Accuracy Research Articles

Force servo nano-precision diamond cutting of freeform surfaces on a micro-precision machine

This paper presents force servo single point diamond cutting of freeform surfaces with nano-precision on a micro-precision machine. For nanometric machining accuracy, traditional diamond cutting based on position servo, requires accurate machine axial motions by ultra-precision machine with high cost, or utilizes a fast tool servo to compensate for machine slide vibration and motion error of common machines that is a complicated procedure. In this paper, nanometric machining accuracy was achieved on a micro-precision machine by force servo diamond cutting, in which the tool can be driven to trace the workpiece surface to compensate for the machine slide vibration, machine motion errors and workpiece incline errors accurately and automatically. For highly sensitive and stable force controlling, force servo nanocutting mechanism (FSNM) based on flexible structures was designed with force sensing resolution down to submillinewton level, and a damping controller was developed to suppress the resonant vibration of the FSNM. For extending application of force servo cutting from fabrication of only discontinuous microstructures to continuous freeform surfaces, referring force maps were developed by considering the real material removal volume of each cutting point. Force servo cutting was then validated by fabricating freeform surfaces with surface form errors of less than 10 nm on silicon spherical surfaces based on the micro-precision machine. The works discussed in this paper provide an effective technique for the fabrication of complex and continuous microstructured and freeform surfaces with nano-precision by common machines only with micron even tens of microns precision.

MODERN PRACTICE OF USING NON-DESTRUCTIVE TESTING METHODS IN TIRE PRODUCTION

Improving the competitiveness of Russian tires requires improving the organization of the quality control system in production. The purpose of the article is to analyze the current state of the application of tire quality control methods in production. A common way to diagnose tires in the Russian industry is random control by road tests and bench tests, leading to the destruction of the product. At the same time, non-destructive testing is widely used in the global tire industry. Tire structural strength, material homogeneity, stiffness and geometric characteristics of tires are checked on test benches, which are the result of defects that can be diagnosed in a “non-invasive” way, i.e. non-destructive testing methods. Visual-optical, eddy current, ultrasonic and radiation methods of non-destructive testing are the most optimal for diagnosing continuity and obtaining the physical and mechanical characteristics of rubber and cord. Continuous flaw detection control of tires allows for the lowest cost diagnostics of hidden defects and timely improvement of the technological process. The interferometric method of non-destructive testing can be considered as an intelligent predictive diagnostics of hidden defects, bubbles, delamination, foreign inclusions in tires with nanometer accuracy. Patents and practical developments of Russian inventors in the field of interferometry testify to the high potential of mass production of domestic flaw detectors for their use in tire factories.

Unravelling DNA Organization with Single-Molecule Force Spectroscopy Using Magnetic Tweezers.

Genomes carry the genetic blueprint of all living organisms. Their organization requires strong condensation as well as carefully regulated accessibility to specific genes for proper functioning of their hosts. The study of the structure and dynamics of the proteins that organize the genome has benefited tremendously from the development of single-molecule force spectroscopy techniques that allow for real-time, nanometer accuracy measurements of the compaction of DNA and manipulation with pico-Newton scale forces. Magnetic tweezers, in particular, have the unique ability to complement such force spectroscopy with the control over the linking number of the DNA molecule, which plays an important role when DNA-organizing proteins form or release wraps, loops, and bends in DNA. Here, we describe all the necessary steps to prepare DNA substrates for magnetic tweezers experiments, assemble flow cells, tether DNA to a magnetic bead inside a flow cell, and manipulate and record the extension of such DNA tethers. Furthermore, we explain how mechanical parameters of nucleoprotein filaments can be extracted from the data.

Spatiotemporal mapping of nanotopography and thickness transitions of ultrathin foam films.

Freshly formed soap films, soap bubbles, or foam films display iridescent colors due to thin film interference that changes as squeeze flow drives drainage and a progressive decrease in film thickness. Ultrathin (thickness <100 nm) freestanding films of soft matter containing micelles, particles, polyelectrolyte-surfactant complexes, or other supramolecular structures or liquid crystalline phases display drainage via stratification. A fascinating array of thickness variations and transitions, including stepwise thinning and coexistence of thick-thin flat regions, arise in micellar foam films that undergo drainage via stratification. In this tutorial, we describe the IDIOM (interferometry digital imaging optical microscopy) protocols that combine the conventional interferometry principle with digital filtration and image analysis to obtain nanometer accuracy for thickness determination while having high spatial and temporal resolution. We provide fully executable image analysis codes and algorithms for the analysis of nanotopography and summarize some of the unique insights obtained for stratified micellar foam films.

Two-dimensional grating interferometer with nanometer accuracy

A two-dimensional grating interferometer with the nanometer accuracy is proposed, which employs a transmissive two-dimensional diffraction grating and a corner cube prism in its optical configuration. The distinctive features of this optical path configuration are as follows: (i) Fourfold optical subdivision is achieved based on the principle of secondary diffraction, enhancing optical subdivision capability. (ii) The utilization of a corner cube prism configuration enables parallel retroreflection of diffracted light, facilitating ease of optical alignment. Utilizing a two-dimensional transmissive grating with a period of 4 µm (resulting in an optical signal period of 1 µm after fourfold optical subdivision), the two-dimensional grating interferometer achieves measurement resolutions better than 8 nm along the x and y directions. Within a 100 µm range, the grating displacement errors are superior to ±38 and ±36 nm. The repeatability (standard deviation of error) during a reciprocating motion with a 4 µm stroke is superior to 14 nm. The proposed two-dimensional grating interferometer enables nanoscale resolution measurements, showcasing notable linear measurement capabilities and repeatability. It finds potential applications in ultra-accuracy positioning and machining equipment. The utilization of gratings with smaller periods holds the promise of realizing picometer-level measurement potential.

Method for a deflection-type refractometer measuring the fringe shift by using linear Fresnelzone plates.

This study describes the design and performance of a deflection-type refractometer based on measuring the fringe shift from the Fresnel diffraction pattern to solve some major limitations of conventional differential refractometers, such as measurement range, resolution, zero balancing, and monitoring analysis. The refractometer apparatus comprises a coherent light source, linear Fresnel zone plate, measuring cell, and image capture device mounted on a movable platform. The distance measurement unit is configured to detect fringe deflection due to the difference in refractive index between the sample and the reference. To achieve this, distance measurements with an accuracy of a few nanometers by using the local frequency method and fringe shift measurement method are quite feasible. The uncertainty in this technique is determined by the smallest change in the longitudinal displacement of the image for which the CCD camera can detect a change in pixel position. The refractive index is obtained with a highly extended measurement range of at least ±0.4R I U and precision of the order of 2×10-4 R I U. A numerical comparison between computer simulation of the diffraction patterns that occur when the linear Fresnel zone plate is illuminated by a plane light traveling parallel to the z axis.

Nanometer flat blazed x-ray gratings using ion beam figure correction.

With the development of nanometer accuracy stitching interferometry, ion beam figuring (IBF) of x-ray mirrors can now be achieved with unprecedented performance. However, the process of producing x-ray diffraction gratings on these surfaces may degrade the figure quality due to process errors introduced during the ruling of the grating grooves. To address this challenge, we have investigated the post-production correction of gratings using IBF, where stitching interferometry is used to provide in-process feedback. A concern with ion beam correction in this case is that ions will induce enough surface mobility of atoms to cause smoothing of the grating structure and degradation of diffraction efficiency. In this study we found however that it is possible to achieve a nanometer-level planarity of the global grating surface with IBF, while preserving the grating structure. The preservation was so good, that we could not detect a change in the diffraction efficiency after ion beam correction. This is of major importance in achieving ultra-high spectral resolution, and the preservation of brightness for coherent x-ray beams.

Low-Field Actuating Magnetic Elastomer Membranes Characterized using Fibre-Optic Interferometry.

Smart robotic devices remotely powered by magnetic field have emerged as versatile tools for wide biomedical applications. Soft magnetic elastomer (ME) composite membranes with high flexibility and responsiveness are frequently incorporated to enable local actuation for wireless sensing or cargo delivery. However, the fabrication of thin ME membranes with good control in geometry and uniformity remains challenging, as well as the optimization of their actuating performances under low fields (milli-Tesla). In this work, the development of ME membranes comprising of low-cost magnetic powder and highly soft elastomer through a simple template-assisted doctor blading approach, is reported. The fabricated ME membranes are controllable in size (up to centimetre-scale), thickness (tens of microns) and high particle loading (up to 70 wt.%). Conflicting trade-off effects of particle concentration upon magnetic responsiveness and mechanical stiffness are investigated and found to be balanced off as it exceeds 60 wt.%. A highly sensitive fibre-optic interferometric sensing system and a customized fibre-ferrule-membrane probe are first proposed to enable dynamic actuation and real-time displacement characterization. Free-standing ME membranes are magnetically excited under low field down to 2 mT, and optically monitored with nanometer accuracy. The fast and consistent responses of ME membranes showcase their promising biomedical applications in nanoscale actuation andsensing.

Amplitude-Resolved Single Particle Spectrophotometry: A Robust Tool for High-Throughput Size Characterization of Plasmonic Nanoparticles.

Plasmonic nanoparticles have a wide range of applications in science and industry. Despite the numerous synthesis methods reported in the literature over the last decades, achieving precise control over the size and shape of large nanoparticle populations remains a challenge. Since variations in size and shape significantly affect the plasmonic properties of nanoparticles, accurate metrological techniques to characterize their morphological features are essential. Here, we present a novel spectrophotometric method, called Amplitude-Resolved Single Particle Spectrophotometry, that can measure the individual sizes of thousands of particles with nanometric accuracy in just a few minutes. This new method, based on the measurement of the scattering amplitude of each nanoparticle, overcomes some of the limitations observed in previous works and theoretically allows the characterization of nanoparticles of any size with a simple extra calibration step. As proof of concept, we characterized thousands of spherical nanoparticles of different sizes. This new method shows excellent accuracy, with less than a 3% discrepancy in direct comparison with transmission electron microscopy. Although the effectiveness of this method has been demonstrated with spherical nanoparticles, its real strength lies in its adaptability to more complex geometries by using an alternative analytical method to the one described here.

Correcting retrace and system imaging errors to achieve nanometer accuracy in full aperture, single-shot Fizeau interferometry.

X-ray mirrors with single-digit nanometer height errors are required to preserve the quality of ultra-intense photon beams produced at synchrotron or free electron laser sources. To fabricate suitable X-ray mirrors, accurate metrology data is needed for deterministic polishing machines. Fizeau phase-shifting interferometers are optimized to achieve accurate results under nulled conditions. However, for curved or aspheric mirrors, a limited choice of reference optic often necessitates measurement under non-nulled conditions, which can introduce retrace error. Using experimental measurements of a multi-tilted calibration mirror, we have developed an empirical model of Fizeau retrace error, based on Zernike polynomial fitting. We demonstrate that the model is in good agreement with measurements of ultra-high quality, weakly-curved X-ray mirrors with sags of only a few tens of microns. Removing the predicted retrace error improves the measurement accuracy for full aperture, single shot, Fizeau interferometry to < 2 nm RMS.

Towards in-line real-time characterization of roll-to-roll produced ZTO/Ag/ITO thin films by hyperspectral imaging

Large area manufacturing processes of thin films such as large-area vacuum roll-to-roll coating of dielectric and gas permeation barrier layers in industry require a precise control of e.g. film thickness, homogeneity, chemical compositions, crystallinity and surface roughness. In order to determine these properties in real time, hyperspectral imaging is a novel, cost-efficient, and fast tool as in-line technology for large-area quality control. We demonstrate the application of hyperspectral imaging to characterize the thickness of thin films of the multilayer system ZTO/Ag/ITO produced by roll-to-roll magnetron sputtering on 220 mm wide polyethylene terephthalate substrate. X-ray reflectivity measurements are used to determine the thickness gradients of roll-to-roll produced foils with sub nanometer accuracy that serve as ground truth data to train a machine learning model for the interpretation of the hyperspectral imaging spectra. Based on the model, the sub-layer thicknesses on the complete substrate foil area were predicted which demonstrates the capabilities of this approach for large-scale in-line real-time quality control for industrial applications.

Time-Resolved Formation and Operation Maps of Pd Catalysts Suggest a Key Role of Single Atom Centers in Cross-Coupling.

An approach to the spatially localized characterization of supported catalysts over a reaction course is proposed. It consists of a combination of scanning, transmission, and high-resolution scanning transmission electron microscopy to determine metal particles from arrays of surface nanoparticles to individual nanoparticles and individual atoms. The study of the evolution of specific metal catalyst particles at different scale levels over time, particularly before and after the cross-coupling catalytic reaction, made it possible to approach the concept of 4D catalysis-tracking the positions of catalytic centers in space (3D) over time (+1D). The dynamic behavior of individual palladium atoms and nanoparticles in cross-coupling reactions was recorded with nanometer accuracy via the precise localization of catalytic centers. Single atoms of palladium leach out into solution from the support under the action of the catalytic system, where they exhibit extremely high catalytic activity compared to surface metal nanoparticles. Monoatomic centers, which make up only approximately 1% of palladium in the Pd/C system, provide more than 99% of the catalytic activity. The remaining palladium nanoparticles changed their shape and could move over the surface of the support, which was recorded by processing images of the array of nanoparticles with a neural network and aligning them using automatically detected keypoints. The study reveals a novel opportunity for single-atom catalysis─easier detachment (capture) from (on) the carbon support surface is the origin of superior catalytic activity, rather than the operation of single atomic catalytic centers on the surface of the support, as is typically assumed.

Surface Lattice Modulation through Chemical Delithiation toward a Stable Nickel-Rich Layered Oxide Cathode

Nickel-rich layered oxides (NLOs) are considered as one of the most promising cathode materials for next-generation high-energy lithium-ion batteries (LIBs), yet their practical applications are currently challenged by the unsatisfactory cyclability and reliability owing to their inherent interfacial and structural instability. Herein, we demonstrate an approach to reverse the unstable nature of NLOs through surface solid reaction, by which the reconstructed surface lattice turns stable and robust against both side reactions and chemophysical breakdown, resulting in improved cycling performance. Specifically, conformal La(OH)3 nanoshells are built with their thicknesses controlled at nanometer accuracy, which act as a Li+ capturer and induce controlled reaction with the NLO surface lattices, thereby transforming the particle crust into an epitaxial layer with localized Ni/Li disordering, where lithium deficiency and nickel stabilization are both achieved by transforming oxidative Ni3+ into stable Ni2+. An optimized balance between surface stabilization and charge transfer is demonstrated by a representative NLO material, namely, LiNi0.83Co0.07Mn0.1O2, whose surface engineering leads to a highly improved capacity retention and excellent rate capability with a strong capability to inhibit the crack of NLO particles. Our study highlights the importance of surface chemistry in determining chemical and structural behaviors and paves a research avenue in controlling the surface lattice for the stabilization of NLOs toward reliable high-energy LIBs.

A Compact Electromagnetic Dual Actuation Positioning System with a 10 mm Range and Nanometer Resolution

In this manuscript, a compact electromagnetic dual actuation positioning system (CEDAPS) based on the Lorentz force principle that features a 10 mm range and nanometer-scale resolution with flexure guides is presented. Firstly, the stiffness of the flexure mechanism is modelled. Secondly, based on it, the primary coil is designed, and from its performance, a suitable secondary coil is made to compensate for the deficiency of the primary actuation subsystem. The characteristics of the forces generated by these coils are also evaluated by an electromagnetic FEA simulation. Thirdly, a control scheme is presented that combines the performances of these two actuators, and finally, a prototype is fabricated to evaluate the performance. The results show a 10 nm resolution for a 10 mm (±5 mm) stroke with low sub-micron sinusoidal tracking errors and nanometer accuracy for step tracking under the proposed control scheme. The thermal properties of the system are also presented.

A pre-time-zero spatiotemporal microscopy technique for the ultrasensitive determination of the thermal diffusivity of thin films.

Diffusion is one of the most ubiquitous transport phenomena in nature. Experimentally, it can be tracked by following point spreading in space and time. Here, we introduce a spatiotemporal pump-probe microscopy technique that exploits the residual spatial temperature profile obtained through the transient reflectivity when probe pulses arrive before pump pulses. This corresponds to an effective pump-probe time delay of 13ns, determined by the repetition rate of our laser system (76MHz). This pre-time-zero technique enables probing the diffusion of long-lived excitations created by previous pump pulses with nanometer accuracy and is particularly powerful for following in-plane heat diffusion in thin films. The particular advantage of this technique is that it enables quantifying thermal transport without requiring any material input parameters or strong heating. We demonstrate the direct determination of the thermal diffusivities of films with a thickness of around 15nm, consisting of the layered materials MoSe2 (0.18 cm2/s), WSe2 (0.20 cm2/s), MoS2 (0.35 cm2/s), and WS2 (0.59 cm2/s). This technique paves the way for observing nanoscale thermal transport phenomena and tracking diffusion of a broad range of species.

Monolayer heterojunction interactive hydrogels for high-freedom 4D shape reconfiguration by two-photon polymerization.

Mimicking natural botanical/zoological systems has revolutionarily inspired four-dimensional (4D) hydrogel robotics, interactive actuators/machines, automatic biomedical devices, and self-adaptive photonics. The controllable high-freedom shape reconfiguration holds the key to satisfying the ever-increasing demands. However, miniaturized biocompatible 4D hydrogels remain rigorously stifled due to current approach/material limits. In this research, we spatiotemporally program micro/nano (μ/n) hydrogels through a heterojunction geometric strategy in femtosecond laser direct writing (fsLDW). Polyethylene incorporated N-isopropylacrylamide as programmable interactive materials here. Dynamic chiral torsion, site-specific mutation, anisotropic deformation, selective structural coloration of hydrogel nanowire, and spontaneous self-repairing as reusable μ/n robotics were identified. Hydrogel-materialized monolayer nanowires operate as the most fundamental block at nanometric accuracy to promise high freedom reconfiguration and high force-to-weight ratio/bending curvature under tight topological control. Taking use of this biomimetic fsLDW, we spatiotemporally constructed several in/out-plane self-driven hydrogel grippers, diverse 2D-to-3D transforming from the same monolayer shape, responsive photonic crystal, and self-clenched fists at μ/n scale. Predictably, the geometry-modulable hydrogels would open new access to massively-reproducible robotics, actuators/sensors for microenvironments, or lab-on-chip devices.

Cell shape and tension alter focal adhesion structure

Cells are not only anchored to the extracellular matrix via the focal adhesion complex, the focal adhesion complex also serves as a sensor for force transduction. How tension influences the structure of focal adhesions is not well understood. Here, we analyse the effect of tension on the location of key focal adhesion proteins, namely vinculin, paxillin and actin. We use micropatterning on gold surfaces to manipulate the cell shape, to create focal adhesions at specific cell areas, and to perform metal-induced energy transfer (MIET) measurements on the patterned cells. MIET resolves the different protein locations with respect to the gold surface with nanometer accuracy. Further, we use drugs influencing the cellular motor protein myosin or mechanosensitive ion channels to get deeper insight into focal adhesions at different tension states. We show here that in particular actin is affected by the rationally tuned force balance. Blocking mechanosensitive ion channels has a particularly high influence on the actin and focal adhesion architecture, resulting in larger focal adhesions with elevated paxillin and vinculin and strongly lowered actin stress fibres. Our results can be explained by a balance of adhesion tension with cellular tension together with ion channel-controlled focal adhesion homeostasis, where high cellular tension leads to an elevation of vinculin and actin, while high adhesion tension lowers these proteins.

Review of the State and Prospects of Development and Application of Domestic Multilayer Piezoactuator for Rocket and Space Technology and Ground space Infrastructure

The article gives an overview of the state of development and applications of actuators in the world. A method and technology for manufacturing domestic multilayer piezoelectric elements by the method of slip casting from the piezomaterial of the PZT system and multilayer piezoelectric actuators based on them is described. It is noted that in terms of their technical level, multilayer domestic piezo products correspond to the best foreign samples. Preliminary studies of multilayer piezoelectric products in Russia and abroad have confirmed their unique capabilities when they work in space instrumentation and ground structures for monitoring and controlling space objects. The results of studies on the use of multilayer piezo products of JSC "NII "Elpa" and their foreign analogues in systems are given. The results of the study of various design options for piezoelectric platforms of angular and linear displacements with nanometric accuracy are presented. The optimal design options are selected based on the use of special multilayer piezoactuator APM-1 and APM-2 for their use in rocket and space technology instruments and ground-based space infrastructure. The technology developed at JSC Research Institute Elpa makes it possible to create promising multilayer piezo products of various classes and purposes for rocket and space equipment and ground-based space infrastructure.

Radial Error Motion Measurement and Its Uncertainty Estimation of Ultra Precision Axes of Rotation with Nanometer Level Precision.

The radial error is the key performance indicator of ultra-precision axis. In order to measure and evaluate the radial error of ultra-precision axis with nanometer accuracy, a measurement system with an accuracy of nanometer based on capacitive displacement probes and standard spheres is developed. The nonlinearity error of capacitive displacement probes, misalignment error of the probes, eccentric error of standard spheres, error caused by environment temperature change, environment vibration and error separation methods are analyzed and the effects of the above factors are obtained; Multiple measurement examples carried out with the measurement system this paaper constructed indicate the repeatability of the measurement system reaches 10.5 nm and the roundness error of artifact separated is less than 4.03 nm. In order to evaluate the measurement dispersion of the ultra-precision axis radial error, the major uncertainty components and the complete process of the comprehensive evaluation of the measurement uncertainty are proposed. The combined uncertainty of radial error motion measurement of the ultra-precision axis with Donaldson reversal is 31.64 nm (k = 2).

A Novel Monopolar Cross-Scale Nanopositioning Stage Based on Dual Piezoelectric Stick-Slip Driving Principle.

The precise characterization and measurement of new nanomaterials and nano devices require in situ SEM nanorobotic instrumentation systems, which put forward further technical requirements on nanopositioning techniques of compact structure, cross-scale, nanometer accuracy, high vacuum and non-magnetic environment compatibility, etc. In this work, a novel cross-scale nanopositioning stage was proposed, which combined the advantages of piezoelectric stick-slip positioner and piezoelectric scanner techniques and adopted the idea of macro/micro positioning. A new structure design of a single flexible hinge shared by a small and large PZT was proposed to effectively reduce the size of the positioning stage and achieve millimeter stroke and nanometer motion positioning accuracy. Then, the cross-scale motion generation mechanism of the dual piezoelectric stick-slip drive was studied, the system-level dynamics model of the proposed positioning stages was constructed, and the mechanism design was optimized. Further, a prototype was manufactured and a series of experiments were carried out to test the performance of the stage. The results show that the proposed positioning stage has a maximum motion range of 20 mm and minimum step length of 70 nm under the small piezoceramic ceramic macro-motion stepping mode, and a maximum scanning range of 4.9 μm and motion resolution of 16 nm under the large piezoceramic ceramic micro-motion scanning mode. Moreover, the proposed stage has a compact structure size of 30 × 17 × 8 mm3, with a maximum motion speed of 10 mm/s and maximum load of 2 kg. The experimental results confirm the feasibility of the proposed stage, and nanometer positioning resolution, high accuracy, high speed, and a large travel range were achieved, which demonstrates that the proposed stage has significant performance and potential for many in situ SEM nanorobotic instrument systems.