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• We analyze the problem areas and distorted signals that can arise when measuring CSMU using basic white-light interferometry. We specifically focus on addressing the structural areas that are prone to errors, ensuring reliable processing results and improving efficiency. • In the signal processing of the problem areas, we employ characteristic analysis of the distorted signal. By filtering out the disturbed part of the signal and extracting the desired portion containing accurate height information, we are able to reconstruct the 3D topography. • This algorithm can be applied to any traditional optical system utilizing white-light interferometry. It is a simple and accurate approach that only requires a standard experimental setup, making it highly practical. Micro-nanostructures refer to technologies that operate at the nanoscale and provide materials and devices with unique mechanical, physical, and chemical properties. These structures have diverse applications in fields such as microelectronics, biotechnology, aerospace, and metamaterials. As precision machining technology advances, the demand for smaller sizes and higher accuracy of structural units has increased, leading to more compact integration. Consequently, the lossless and high-precision 3D measurement of highly integrated micro-nanostructure components has become increasingly challenging. In this study, we analyzed measurement errors in compactly spaced microstructural units using white-light scanning interferometry and proposed an algorithm to optimize this technology. By combining coherent peak-histogram processing with signal correlation analysis, we were able to improve the measurement accuracy by approximately ten times compared to current mainstream algorithms. To validate our algorithm, we performed experiments using metasurfaces with structural unit spacing at the order of sub-micrometer. The results obtained demonstrated the effectiveness of our algorithm in achieving accurate measurements. [ABSTRACT FROM AUTHOR]

The absolute testing technique has been widely employed in sub-nanometer optical surface metrology, we have presented a generalized shift-rotation absolute measurement method for high-numerical-aperture spherical surfaces (Yang et al., 2017). In this paper, a simple and effective three-step shift-rotation absolute testing technique for optical surface figure with irregular shaped aperture is presented. The test surface is tested in an original, a rotational and a shift position. Based on the orthonormal polynomials over irregular shaped aperture, the absolute figure of the test surface is separated from the reference surface errors by the two measurement difference data. Simulation results presented in the paper indicated the validity of the three-step shift-rotation absolute measurement method. The measurement results show a good agreement with the results measured by commercial profiler. The novel three-step shift-rotation absolute testing technique is a promising method to measurement the optical flat and spherical with the irregular shaped aperture. [ABSTRACT FROM AUTHOR]

We demonstrate a lensless phase-shifting point diffraction interferometer with a tiny pinhole to measure spherical mirror surface figures. The interferograms used to reconstruct the surface figure are formed without imaging optics. Fresnel diffraction calculations with a coordinate transformation are studied as a means of reconstruction method for wavefront amplitude and phase. The Radon transform is used to determine the distance from the tiny pinhole to the CCD target, which guarantees the accuracy of the diffraction calculations. Our lensless phase-shifting point diffraction interferometer not only retains the higher measurement precision by the ideal reference wavefront, but also overcome the fabrication and mounting limitation of the imaging optics. The simulations and experiments have validated the accuracy and feasibility of the spherical mirror measurement by proposed lensless phase-shifting point diffraction interferometer. [ABSTRACT FROM AUTHOR]

Non-null interferometry could use to measure the radius of curvature (ROC), we have presented a virtual quadratic Newton rings phase-shifting moiré-fringes measurement method for large ROC measurement (Yang et al., 2016). In this paper, we propose a large ROC measurement method based on the evaluation of the interferogram-quality metric by the non-null interferometer. With the multi-configuration model of the non-null interferometric system in ZEMAX, the retrace errors and the phase introduced by the test surface are reconstructed. The interferogram-quality metric is obtained by the normalized phase-shifted testing Newton rings with the spherical surface model in the non-null interferometric system. The radius curvature of the test spherical surface can be obtained until the minimum of the interferogram-quality metric is found. Simulations and experimental results are verified the feasibility of our proposed method. For a spherical mirror with a ROC of 41,400 mm, the measurement accuracy is better than 0.13%. [ABSTRACT FROM AUTHOR]

We propose a high-order shift-rotation absolute ultra-precision measurement method to calibrate the misalignment aberration and reference surface deviation in high-numerical-aperture spherical surface testing. Based on high-order approximation, the high-order misalignment aberrations are deduced. Both the computer simulation and experimental results confirm the feasibility of the proposed absolute ultra-precision measurement method. The high-order misalignment aberrations and reference surface deviation can be removed from the measured results by our absolute measurement method. The high-order shift-rotation absolute measurement method can get the accuracy of nanometer level in high-numerical-aperture spherical surface testing. [ABSTRACT FROM AUTHOR]

Misalignment aberrations in Fizeau interferometric testing system can significantly influence the measurement results in the case of high-numerical-aperture test spherical surfaces, and it is hard to separate the high-order misalignment aberrations from the measured data. The traditional calibration method, which is based on linear-approximation, is applicable in calibrating only the linear misalignment aberration in measurement of high-numerical-aperture spherical surfaces. Based on modified power term for interferometry and 4-overlapping averaging 9-frame algorithm, sub-nanometer accuracy high-order calibration method is proposed to calibrate the linear misalignment aberrations as well as high-order misalignment aberrations. Both the computer simulation and experimental results confirm the feasibility and accuracy of the proposed calibration technique, and sub-nanometer misalignment aberrations can be calibrated. The proposed method can also used in spherical surface ultra-precision measurement by other interferometric setups without foreknowledge of numerical aperture of the test surface. [ABSTRACT FROM AUTHOR]

Abstract: A method for measuring the radius of curvature with a pinhole point diffraction interferometer (PDI) is proposed. Using the wavefront difference method and the Gaussian imaging equation, the longitudinal displacement of the converging rays passing through a standard plane-parallel-plate sample in PDI interference cavity is determined. Based on this longitudinal displacement, a precise formula for radius of curvature calculation is deduced. An experimental system for radius of curvature measurements is set up to verify the principle. With this testing system, the radius of curvature of spherical mirrors and the surface figure can be measured in a higher precision simultaneously. Some sources of uncertainty in measurement are discussed based on detailed error analysis. The experimental results indicate that the measurement accuracy is in the order of 10−4. [Copyright &y& Elsevier]

We proposed a new method for the radius of curvature (ROC) of spherical wave measurement based on vortex beam interference and Fermat's spiral fitting, which can not only provide a large measurement range but also have high precision. Theoretical analysis showed that the maximum distribution of the interference light intensity is in accordance with the Fermat's spiral, and the spiral coefficient is proportional to the ROC of spherical wave. For a concave spherical mirror with a ROC of 899.89mm and a convex spherical lens with a ROC of 59.99mm, the average measurement error of five measurements are 0.080% and 0.083%, respectively. Controlled experiments showed that, our proposed method has a higher measurement accuracy and a larger measurement range than Newton's rings method, it has almost equal measurement accuracy for large and small ROC. This research provides a theoretical basis for the development of a ROC measurement system with large measurement range and high precision. [ABSTRACT FROM AUTHOR]

In this report, a method is proposed to demodulate a single-shot interferogram based on deep learning using a convolutional neural network (CNN). The time required to demodulate a single interferogram is on the order of milliseconds. The root mean square (RMS) of the residual wavefront between the original wavefront and the estimated wavefront reached the order of 10−2 λ. Moreover, the cost was lower than using commercial dynamic and phase-shifting interferometers. This method yielded superior real-time performance and high precision. The results indicated that this approach based on deep learning is robust and feasible for demodulating single-shot interferograms. • A method based on deep learning is proposed to demodulate a single shot interferogram. • The single shot interferogram is used as the input of the convolutional neural network, and the Zernike polynomials coefficient is output. • Compared with other methods of demodulating a single shot interferogram, the method is faster, and the speed of demodulating an image is in the order of microseconds. The RMS (Root-Mean-Square) of the residual wavefront between the original wavefront and the estimated wavefront approached 10 − 2 λ. • The cost of the method is lower than commercial dynamic and phase-shifting interferometers. In addition, we compare the speed and accuracy of the method with the Zygo interferometer, and find that the method leads to better or comparable results yet is orders of magnitudes faster.it will be great helpful for the dynamic fringe demodulation or other real-time applications. • The process of demodulation of the convolutional neural network is robust. [ABSTRACT FROM AUTHOR]

We propose a numerical robust phase aberration compensation method in digital holographic microscopy, which is based on self-extension of holograms. We remove the fringes of the sample area in the hologram, then expand the fringe to fill the removed area of hologram by self-extension. The sample-free reference hologram is obtained which contain the total aberration of the system. The quantitative phase imaging of samples is separated from measurement phase data by the difference phase map of captured and reference hologram. Numerical simulation and experimental results demonstrate the availability of the proposed aberration compensation method in digital holographic microscopy. [ABSTRACT FROM AUTHOR]

In ptychography, the precise axial distance between the sample and the detector is of vital importance to retrieve the tested object with high quality, but the axial distance error cannot be entirely eliminated in the practical experiments. An autofocusing strategy based on dichotomy is proposed to rapidly correct the axial distance error. In this strategy, the total variation function that is valid for both amplitude- and phase-modulating specimens is applied to determine whether the current distance is smaller or larger than the true distance. Further, the dichotomy is used to exponentially shrink the step-size of the correction by iterative computations, which means that for the early iterations large modified step-size is used and for later iterations only small step-size is considered. Therefore, the dichotomy is beneficial to quickly confirm the accurate axial distance with few computations. Simulations and experiments are conducted to demonstrate that our proposed strategy, based on the extended ptychographic iterative engine (ePIE), is capable of calibrating the sample–detector distance with high accuracy and efficiency. [ABSTRACT FROM AUTHOR]

• In this research, we proposed a novel optical surface shapes measurement method based on conformal mapping-angular phase-shifting interferometry. It paves the way for the application of vortex beams in the field of optical surface shape measurement. It is of great significance to the miniaturization design of high-precision interferometers, and can significantly reduce the experimental cost. • We use a Q-plate in the reference optical path to introduce a 90-degree phase shift, and conformal mapping is used to demodulate the surface shape. • This method not only ensures the accuracy of surface shape measurement; but also avoids the use of expensive precision translation stages; and has specific anti-vibration performance. • The measuring device is simple, compact, easy to operate and low cost. We proposed a novel optical surface shapes measurement method based on conformal mapping-angular phase-shifting interferometry (APSI). This method rotates a Q-plate in the reference light path to introduce a 90-degree phase shift. The mathematical tool of conformal mapping is used for surface shape demodulation. After removing the helical phase in the compound phase, high-precision surface shape measurement results are obtained, and the measurement surface shape deviations are 3.33 nm (PV) and 0.26 nm (RMS). This work paves the way for surface shape measurement and compound phase demodulation using vortex beams. [ABSTRACT FROM AUTHOR]

• A simple and effective strategy is proposed to measure the focal lengths. • It enables non-contact measurement and no need to measure the distance between optics components. • The entire measurement system occupies a small space that is easy to set up and operates. This paper proposes a new method to measure the focal lengths of both convex and concave lenses based on vortex beam interference. Theoretical analysis illustrates that the maximum intensity distribution of the interferogram is in accordance with the Fermat's spiral, and the spiral coefficient is proportional to the difference between the focal length of the test lens and the distance from the test lens to the camera. In order to calculate the precise focal length, we separately block the light paths to obtain the reference and test beam spots, and get the ratio of these two spot sizes. Then, the ratio and the spiral coefficient are used to determine the focal length. For a biconvex lens with a focal length of 200 mm and a biconcave lens with a focal length of −100 mm, the relative measurement errors are 0.0892 % and 0.0800 %, respectively. This research provides a novel and convenient method for measuring the focal length, and no-sophisticated displacement devices and moving the lens to be measured are required in the measurement. [ABSTRACT FROM AUTHOR]

Digital holographic microscopy is a high-precision, high-resolution quantitative detection method, however, aberration compensation significantly increases the data processing time. We herein propose a method based on sequential shift and a differential–integral algorithm to compensate for fast phase aberrations. The proposed method obtains the phase derivative of the real sample phase information through holograms at different positions and then reconstructs the aberration-free phase result through integration. The compensation avoids complex phase polynomial fitting calculations or optimization iterations, achieves extremely fast aberration compensation, and can theoretically eliminate various low and high-order aberrations, including extremely complex aberrations. We experimentally validate the effectiveness and high speed of the proposed method by imaging paramecium samples. • Avoid complex calculations or iterations to achieve fast aberration compensation. • Can be applied to any traditional digital holographic microscope optical system. • Various low-order and high-order aberrations can be eliminated theoretically. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of intraocular pressure (IOP)-reducing treatment on the development of disc hemorrhages in patients with glaucoma. Design: Prospective cohort study of patients in the Early Manifest Glaucoma Trial, followed up to 11 years (median = 8 years). Participants: Patients with newly detected glaucoma randomized to argon laser trabeculoplasty plus betaxolol (n = 129) or no initial treatment (n = 126), followed with tonometry, perimetry, and ophthalmoscopy every 3 months, and fundus photography every 6 months. Methods: Logistic regression expressed as odds ratios (OR) and 95% confidence intervals (CIs), analysis of variance, and Cox time-dependent models, expressed as hazard ratios (HRs) and CIs. Main Outcome Measures: Presence (yes/no) and frequency of disc hemorrhages. Results: Disc hemorrhages were identified in approximately 55% of all patients, whether by ophthalmoscopy or review of photographs. In analyses including data up to the time of progression, disc hemorrhages were equally common among treated and control patients: 51.2% versus 45.2%, respectively (P = 0.34), based on ophthalmoscopy, and 50.4% versus 44.4%, respectively (P = 0.34), based on photographs. Gender was the only factor related to the presence of disc hemorrhages detected by both ophthalmoscopy (OR = 0.48; CI, 0.26–0.88; P = 0.022) and photographs (OR = 0.64; CI, 0.38–1.09; P = 0.099) for male patients. The frequency of disc hemorrhages over time did not differ between treated and control patients: 8.4% versus 8.5%, respectively (P = 0.93), based on ophthalmoscopy, and 12.4% versus 11.2%, respectively (P = 0.36), based on photographs. Disc hemorrhages were significantly associated with time to progression (HR = 1.02; CI, 1.01–1.04), and there was no evidence of interaction between treatment group and disc hemorrhages. Conclusions: IOP-reducing treatment was unrelated to the presence or frequency of disc hemorrhages. The results may suggest that disc hemorrhages cannot be considered an indication of insufficient IOP-lowering treatment, and that glaucoma progression in eyes with disc hemorrhages cannot be totally halted by IOP reduction. The results also suggest that disc hemorrhages do not occur in all patients with glaucoma. Financial Disclosure(s): The authors have no proprietary or commercial interest in any materials discussed in this article. [Copyright &y& Elsevier]

White-light scanning interferometry is an effective and widely used technology for measuring the microscopic three-dimensional morphology of an object. Its vertical resolution can reach the sub-nanometer level, and its lateral resolution reaches submicron level. However, for the samples containing complex structure or high-density periodic distribution structural units, the measurement results are strongly restricted by magnification and numerical aperture (NA) of the microscopic objective. In this paper, we proposed a three-dimensional reconstruction algorithm for white-light interferograms after super resolution processing, using fast super-resolution convolutional neural networks (FSRCNN) to improve the detailed information of the interferograms, and then we used centroid method combined with the five-step phase-shift method to extract the zero optical path difference (ZOPD) position of the interference signal after super resolution processing. After processed by the proposed method, the interferograms collected by the 10X microscope objective (NA=0.3) recovered the 3D surface is the same as that measured by the 100X microscope objective (NA=0.7), which is proved by the experiment results. [ABSTRACT FROM AUTHOR]

• STP method can retrieve the synthetic-wavelength phase from moiré fringe patterns in simultaneous dual-wavelength interferometry. • In STP method, by the additive-to-multiplicative moiré fringe transition, the measured synthetic-wavelength interferometry information exists directly and is demodulated conveniently. • STP method is implemented with π/(2k) phase shift at the synthetic wavelength to be retrieved by the conventional phase-shift algorithm. • STP method releases the restriction of spatial carrier for spectrum separation and the requirement of quadratic polar coordinate transform for the circle carrier. • The separation distance of the phase lobes in spectrum for STP method is longer than 9.56 times of the distance for traditional temporal FT method. Simultaneous dual-wavelength interferometry (SDWI) could extend the measured range of each single-wavelength interferometry, and has higher efficiency when the two single wavelengths work simultaneously. However, the directly measured phase demodulation at the long synthetic wavelength (λ S) from the generated moiré fringe patterns in SDWI is rather arduous. To reduce the difficulty of the processing for the moiré fringe patterns, a synthetic wavelength temporal phase retrieval method (STP) with the π/(2k) phase shift at λ S was proposed in this paper. By the additive-to-multiplicative moiré fringe transition, the synthetic-wavelength interferometry information exists in the form of the superposition with other wavelength information. And then for the longer separation distance of the phase lobes in spectrum, the synthetic-wavelength spectrum in STP method could be filter out more easily than traditional temporal Fourier transform (FT) method. After a low-pass filtering in the spectrum of the multiplicative moiré fringe intensity and adopting the π/(2k) phase shift at λ S , the synthetic-wavelength phase is retrieved by the conventional phase-shift algorithm from the obtained synthetic-wavelength phase-shift interferograms with the interval of π/2 phase shift. Compared with the spatial FT method with the introduction of spatial carrier, STP method releases the restriction of spatial carrier for spectrum separation and the requirement of quadratic polar coordinate transform for the circle carrier. Finally, the feasibility and applicability of the STP method are verified using simulation and experimental results. [ABSTRACT FROM AUTHOR]

Abstract A single shot ptychographic iterative engine based on chromatic aberrations is proposed to retrieve the object with fast data acquisition and convergence. In the imaging system, the specimen is irradiated by a RGB illumination source, and the RGB light transmitted through the specimen is recorded by a color sensor. There are three different sizes of the spots on the object surface generated by the lens with chromatic aberrations and the aperture stop, which can produce partially overlapping between adjacent wavelength illumination areas that will lock the object's phase information and ensure retrieve the object successfully. In the reconstruction algorithm, an initial object guess is established by spectrum synthesis method to accelerate convergence and suppress noise. The data acquisition time is dramatically reduced by our proposed single shot method. Highlights • This method overcomes the time-consuming data acquisition and positioning error of PIE. • The initial object spectrum synthesis can accelerate convergence and suppress noise. • Single shot method makes it possible to observe images of the moving object and live cell. [ABSTRACT FROM AUTHOR]

Dual-wavelength interferometry (DWI) could extend the measured range of each single-wavelength interferometry. The synchronization of the two working wavelengths in DWI is of high efficient, and the generated moiré fringe indirectly represents the information of the measured long synthetic-wavelength ( λ S ) phase. However, the extraction of the measured synthetic-wavelength phase is rather arduous from the moiré fringe. To retrieve the synthetic-wavelength phase from the moiré fringe patterns, we present a carrier squeezing dual-wavelength interferometry method (CSDI) in simultaneous DWI (SDWI). After the mathematical square of the moiré fringe patterns, the multiplicative moiré phase-shift fringe patterns with π/2 phase shift at λ S are combined into a single spatial-temporal fringe (STF). By converting the temporal phase shift into spatial carrier and the introduction of the carrier, the measured synthetic wavelength phase is retrieved by the filter and inverse Fourier transform of the STF spectrum. Compared with other methods, CSDI method could suppress the influence of the phase-shift error and only requires 4 frame phase-shift interferograms. Numerical simulations are executed to demonstrate the performance of the CSDI method in SDWI with the peak-to-valley (PV) value of 1.46 nm and the root mean square (RMS) values of 0.23 nm for the demodulated error. And the precision is better than PV of 20 nm (0.0059 λ s ) and RMS of 6 nm (0.0017 λ s ) even when the distribution range of the phase-shift error is as high as ± 10% relative to the π/2 phase shift step at λ S . Finally, our experimental results indicate that the measurement accuracy is better than 1.3% for a step with the height of 7.8 µm, and 0.5% for the step height of 6.233 µm for a Fresnel lens. [ABSTRACT FROM AUTHOR]

We propose a novel micro-displacement measurement system that employs a modified reversal shearing interference structure based on vortex beam interference. The micro-displacement in the measurement path caused a change in the light path and resulted in an optical path difference (OPD) between the reference and measurement paths. This OPD led to the rotation of the petal-like pattern obtained by the interference between two paths. The rotation angle of the petal-like pattern was proportional to the OPD caused by micro-displacement. We used the virtual phase-shifting method to extract the helical phase front, and the Radon transform to measure the angle of the helical phase front. We achieved a high-accuracy micro-displacement measurement with a measurement error of less than 0.067 nm when using a vortex beam with a topological charge of six. This system has an extremely simple structure and is easy to adjust. It is of great significance to the miniaturized design of high-precision displacement sensors. • Avoid complex optical path and adjustments to achieve accurate displacement measurements. • Radon transform was used to solve the rotation angle of the dislocation line in the phase front. • Slight swing of the retroreflector will not change the direction of the measurement beam, this structure is more stable for displacement measurement based on conjugated vortex beam interference. [ABSTRACT FROM AUTHOR]

• Only a single interferogram is needed to complete the high-precision measurement of large ROC, which avoids the time-consuming process of acquiring interferograms. • This method uses a large step size to find a rough solution in a wide search range, and then constructs a shrunken range with a small step size based on the rough solution to quickly determine the high-precision measurement results. • Simulation and experimental results show that our method has high measurement accuracy in different interference models but also measurement efficiency is significantly improved. The method, based on searching the maximum or minimum of the metric function in the defined range that can be used to confirm the expected value, has been applied for measuring the large radius of curvature (ROC). The small step size is always needed in the searching range to ensure the measurement accuracy. But in the wide searching range, it will consume much time for finding the expected value. In order to improve the measurement efficiency, this paper proposes a fast measurement strategy for large ROC. This method uses a large step size to find a rough solution in a wide search range, and then constructs a shrunken range with a small step size based on the rough solution to quickly determine the high-precision measurement results. Simulation and experimental results show that the proposed method can be flexibly applied to different interference systems and greatly improve their measurement efficiency. For the tested spherical mirrors with ROC of 41400 mm and 1000 mm, high precision ROC can be obtained in just a few seconds. [ABSTRACT FROM AUTHOR]

• The CCFC method could extract the synthetic-wavelength interferogram from moiré fringe patterns in simultaneous dual-wavelength interferometry without the introduction of other wavelength interferometric information. • Coupled by the multiplication for the conjugate complex functions, only the lower beat-frequency synthetic-wavelength interferometric fringe pattern is derived directly. • The half-band filter in used in CCFC method is appropriate for the different spectral width or carrier spatial frequency. • The necessary introduced linear carrier in CCFC method is merely about 0.0947 times of the carrier in the traditional spatial domain fourier transform demodulation theory numerically. • The introduced carrier is only used to pursue the separation between the ±1 order phase lobes instead of the separation between the different wavelength phase lobes in CCFC method. Simultaneous dual-wavelength interferometry (SDWI) supplies a better solution to extend the measurement range of traditional single-wavelength interferometry with higher efficiency. To decompose the needed longer beat-frequency synthetic-wavelength (λ S) information from the generated moiré fringe pattern in SDWI, a conjugate complex function coupling strategy (CCFC) of interferometric field is proposed in this study. By the Fourier transform and the half-band filter in one side of the spectrum, the positive half spectrum is obtained. The inverse Fourier transform and conjugate operation are performed on the half spectrums to obtain the two conjugate complex functions of the interferometric field. Coupled by the multiplication for the conjugate complex functions, the lower beat-frequency synthetic-wavelength interferometric fringe pattern is derived directly. And if the SDWI is implemented with the π/2 phase shift at λ S , the obtained phase-shift interferogram for λ S could be demodulated by the conventional phase-shift algorithm. Compared with other spatial-domain Fourier transform demodulation theory, the half-band filter used in CCFC method is appropriate for the different spectral width and carrier spatial frequency. The necessary introduced linear carrier is merely about 0.0947 times of the carrier in the former numerically. And it is only used to pursue the separation between the ±1 order phase lobes instead of the separation between the different wavelength phase lobes. The feasibility and applicability of the CCFC method are verified using simulation and experimental results. [ABSTRACT FROM AUTHOR]

Sparsely and randomly distributed internal defects in the optical component can cause an inferior signal quality and serious measurement errors. A modified three-dimensional extend ptychographic iterative engine (modified-3PIE), which splits a sample into axial sections with known positions, is proposed to evaluate and reconstruct internal defects. The axial positions of internal defects are calculated to reduce the number of axial sections. There are only several axial sections with defects that are located at the calculated positions, and other sections are free-propagation parts. The complex amplitude transmittances of internal defects at different axial section positions are simultaneously retrieved. Simulation and experiments are conducted to verify the performance of the proposed method. Our proposed method does not require a reference beam and imaging system, and it can be applied to reconstruct a large area of the sample. [ABSTRACT FROM AUTHOR]

• This strategy only uses a single interferogram, which will reduce data acquisition requirements and improve measurement efficiency. • Based on the theoretical analysis of the optical propagation path in the experimental system, a simple method is derived to correct the retrace error and established a matching model. • Simulation and experimental results show that our method not only has high-accuracy of measuring small ROC, but also performs well in the measurement of large ROC. We proposed an iterative correlation coefficient matching strategy for the high-precision measurement of the radius of curvature (ROC), which only needs a single-frame interferogram. This strategy includes two parts: one is to obtain an initial ROC by using the relationship between the ROC and the diameter of the dark ring; other is to further solve a high-precision value by an iterative method. In the iterative part, we simulated a series of interference patterns with each ROC in the setting range, and calculated the correlation coefficient between the each simulated interferogram and the measured interferogram, and searched the maximum of the correlation coefficient that would be used to confirm a new ROC in the next iteration. When the calculated ROCs in the adjacent iterations meet the termination condition, the high-accuracy ROC can be solved. The feasibility of our proposed method has been verified by simulations and experiments. The errors of the test mirrors with the ROC of 101.6 mm and 1000 mm are 0.013% and 0.024% in experiments, respectively. This research provides a simple and feasible method for realizing the high-precision ROC measurement. [ABSTRACT FROM AUTHOR]

In this work, graphene and titanium dioxide nanoparticles nanocomposite modified glass carbon electrode (GR–TiO 2 /GCE) was developed to serve as a sensor for simultaneous determination of catechol (CC) and hydroquinone (HQ). The GR–TiO 2 nanocomposite was characterized by using scanning electron microscopy and electrochemical impedance microscopy. The application of GR–TiO 2 nanocomposite in simultaneous determination of CC and HQ was investigated by cyclic voltammetry and differential pulse voltammetry. The GR–TiO 2 nanocomposites modified electrode displays excellent electrochemical catalytic activities toward CC and HQ, which could be attributed to high electrical conductivity and larger surface area of GR–TiO 2 nanocomposites. The oxidation peak currents of CC and HQ were linear over the range of 0.5–100 μM with the detection limits of 0.087 μM for CC and 0.082 μM for HQ, respectively. In addition, the modified sensor shows excellent anti-interference from resorcinol, phenol and nitrobenzol due to their different oxidation peak potentials. The proposed sensor was successfully applied in the simultaneous determination of CC and HQ in tap and lake water samples with satisfied results. [ABSTRACT FROM AUTHOR]

Abstract: Flow behavior of gas and particles in a CFB riser is simulated by a Euler–Lagrangian approach. Collisional interaction of particles is modeled by a direct simulation Monte Carlo (DSMC) method. The coefficient of restitution depends on the relative velocity between two particles by taking into account both the viscoelastic and plastic deformations of particles. The Newtonian equations of motion are solved for each simulated particle in the system. The interaction between gas phase and simulated particles is determined by means of Newtonian third law. A criterion proposed by Soong et al. [C.H. Soong, K. Tuzla, J.C. Chen, Experimental determination of clusters size and velocity in circulating fluidized beds, in: J.F. Large, C. Laguerie Eds., Fluidization VIII Engineering Foundation, New York, 1995, pp. 219–227.] is used to obtain information of clusters. A model for the determination of the number of particles inside a cluster is proposed from kinetic theory of granular flow. The flow behavior of clusters and dispersed particles in the riser is numerically predicted. Distributions of granular temperature of clusters and dispersed particles are computed from velocity distributions. The upward moving clusters give a high granular temperature in comparison to the downward moving clusters. The granular temperature of the dispersed particles is an order of magnitude larger than that of the clusters. The computed collision frequencies of dispersed particles and clusters from DSMC are lower than those from kinetic theory of granular flow. [Copyright &y& Elsevier]

Abstract: In current network-on-chip (NOC) studies and in practical applications, the mesh structure is the most widely used and deeply researched structure. However, the hypercube structure is more symmetrical and regular than the mesh or torus structures. This paper compares the network characteristics of these three direct topologies and proposes a method to compress the hypercube into a plane structure. This structure, which has the multidimensional property based on the hypercube, is called the multidimensional plane (MDP) NOC. The compression process is divided into two steps: the transformation of router denotations and the connection of channels. Then, SystemC is used to implement the MDP NOC and it is compared with the mesh and torus NOCs in terms of four aspects of performance, including average latency time, normalization throughput, energy consumption and area cost. [Copyright &y& Elsevier]

cGVHD exhibits both autoimmune and fibrotic features across multiple organ systems. KD025 is an orally available Rho-associated coiled-coil kinase 2 (ROCK2) selective inhibitor. KD025-208 enrolled 3 cohorts (C1: 200 mg QD, C2: 200 mg BID, and C3: 400 mg QD) of cGVHD patients (pts) after 1-3 prior lines of therapy. Treatment was until progression or toxicity. Primary endpoint is overall response rate (ORR) per 2014 NIH response criteria. Additional endpoints include Duration of Response (DOR), corticosteroid (CS) dose reductions, Failure Free Survival (FFS) and Lee Symptom Scale (LSS) score. 17, 16, and 21 pts enrolled in C1, C2, and C3. As of 8Mar19, median duration of follow up was 112, 97 and 64 weeks (wks) respectively. Median age was 52 yrs, median time from cGVHD diagnosis was 20 mos, and median prior lines of therapy was 2. Median duration of treatment was 37, 33, and 39 wks, respectively. 14 pts remained on KD025. Reasons for discontinuation: cGVHD progression (18), voluntary withdrawal (7), relapse of underlying disease (5), investigator decision (5), AE (3), and death (2). ORR [95% CI] was 65% [38, 85] in C1, 69% [41, 89] in C2, and 62% [38, 82] in C3, 65% [51, 77] across all 3 cohorts. Responses were achieved across key subgroups with ORRs of 62% (24/39) in pts with ≥2 prior lines of therapy, 70% (19/27) in pts with ≥4 organs involved and 60% (25/42) in pts with severe cGVHD, and 65% (22/34) in pts refractory to their previous line. CRs were observed in all affected organs except lung; PRs were observed in lung. Median Time to Response was 8.14 wks (IQR 8-12); 4/35 responses occurred after 24 wks. Responses were durable with a Kaplan-Meier median DOR of 34 wks across all cohorts. 57% of responders sustained a response for ≥20 wks. FFS at 6, 12 and 24 mos was 76%, 47% and 33% respectively. Overall survival was 94%, 91% and 83%. Baseline median CS dose was 0.21 mg/kg/day (prednisone eq). During treatment, median CS dose was reduced by 50%. 20% pts discontinued CS. 52% of pts reported a ≥7-point reduction in LSS with median time to improvement 9 wks. AEs were consistent with those expected in cGVHD pts receiving CS. Common AEs were URI 35%, diarrhea 31%, nausea 31%, fatigue 30%, dyspnea 28%, increased LFTs 24%, and peripheral edema 22%. 63% had a Grade ≥3 AE, the most common was dyspnea, 13%. <10% pts experienced Grade 3 anemia, neutropenia, or thrombocytopenia. SAEs, reported in 43%, were not related to KD025. SAEs in >2% were dyspnea (7%), lung infection (6%), hypoxia (4%) and flu-like illness (4%). Three pts discontinued KD025 due to possibly related AEs (C1: diarrhea, headache; C3: fatigue). 3 pts died on study (C3: relapse of leukemia; lung infection; cardiac arrest), all considered unrelated to KD025. Durable and clinically meaningful responses have been seen across all 3 cohorts. KD025 was well tolerated, with sustained responses and encouraging FFS in patients with advanced cGVHD. [ABSTRACT FROM AUTHOR]

A novel white-light interference signal leakage sampling points (LSPs) correction method based on Morlet wavelet transform and phase seven-step phase shift algorithm (PSA) is presented in this paper. During the correction process, the method can eliminate the LSPs error accurately without changing traditional optical system. Meanwhile, it can effectively de-noise the interference signals and calculate a relatively smooth recovery shape. • The main advantage of the LSPs correction method is that we use wavelet transform to find LSPs in white-light interference signals innovatively for its characteristic of the wavelet coefficient at the distortion points position are different from the general positions, which is different from the traditional method of using wavelet transform for noise reduction and ZOPD extraction. • Furthermore, the algorithm can be applied for any traditional optical system of white-light interferometry. It is simple, accurate and easy to optimize other algorithms. White-light scanning interferometry has become a well-established tool for measuring the microscopic three-dimensional morphology of objects. However, it is sensitive to external disturbances and suffers from leakage sampling, which compromises the accuracy of the measurements. To avoid the error, a robust correction method is proposed, based on wavelet transform, to find leakage sampling point (LSP), and the cubic spline interpolation method is used to complete the interference signal to achieve the signal correction. Further, phase evaluation at each pixel provides a high vertical resolution to characterize the microstructure. In addition, the proposed method exhibits a good denoising performance. Simulations and comparison experiments demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]