Ring Bands Research Articles

Ultra-pixel precision correction method for maskless lithography projection distortion.

Distortion is a common issue in projection lens imaging, leading to image distortion and edge deformation, which significantly affects the quality of the projected pattern. Conventional methods for distortion correction are typically constrained by the precision of the projection pixel size. In this work, we propose an ultra-pixel precision correction method for projection distortion in projection lithography systems. By fitting the position error between the projected pattern and the calibration pattern, and combining the overlapping lithography method with the digital correction method to reduce quantization error, we have overcome the limitation of pixel size on correction precision, thereby achieving ultra-pixel precision calibration of the projected pattern. The resulting position error of the final exposed pattern can be reduced to approximately 1µm (with a projection pixel side length of 5.4µm). The zone plate fabricated using this method exhibits extremely high ring band position accuracy, and the diffraction test patterns are highly consistent with the simulation results. Our ultra-pixel precision correction method, based on a calibration substrate, is characterized by its simplicity of operation, cost-effectiveness, and wide adaptability. It plays a pivotal role in enhancing the quality of lithographic patterns within lithography systems.

Ring only repair of bileaflet mitral valve prolapse with mitral regurgitation: Insights from computational modeling

This study evaluates the efficacy of annuloplasty repair as a standalone procedure for treating bileaflet mitral valve prolapse with mitral regurgitation (MR). Various flexible ring bands for MR of different severities were compared to assess their biomechanical impact and treatment outcomes. Computational beating heart models, based on the Living Heart Human Model, were utilized to simulate annuloplasty repairs. Repairs using bands of varying lengths were modeled on moderate and severe MR cases, considering bileaflet mitral valve prolapse. Key parameters, including regurgitant orifice area (ROA), prolapse severity, coaptation length, leaflet position, and deformation, were computed to compare conditions before and after implantation. Annuloplasty repairs effectively reduced the ROA in both moderate and severe MR cases, achieving complete sealing in selective instances. Additionally, annuloplasty repair corrected bileaflet prolapse, with prolapse severity decreasing as the annular size increased. Successful coaptation was indicated by the expansion of each leaflet’s contact area distribution and percentage in contact with the opposing leaflet. The risk of systolic anterior motion, that may obstruct the left ventricular outflow tract, was minimized, as the anterior leaflet was directed towards the posterior position. In conclusion, annuloplasty repair alone can effectively treat MR when an appropriate band length is selected. It facilitates a significant reduction in ROA, correction of bileaflet prolapse, and improvement in leaflet coaptation. These findings have important clinical implications, potentially offering a less complex surgical treatment avenue and reducing complications in the management of MR.

Durability of annuloplasty in patients with atrial functional mitral regurgitation associated with atrial fibrillation

ObjectiveTo determine the durability of mitral valve repair (MVr) with complete ring or flexible band annuloplasty in patients with atrial functional mitral regurgitation (AFMR) due to atrial fibrillation (AF) and identify risk factors associated with postoperative recurrence of mitral regurgitation. MethodsBetween January 1, 2000, and January 1, 2023, 194 adults with a history of AF underwent MVr with annuloplasty alone for moderate/severe AFMR. Exclusion criteria were prior cardiac surgery, additional repair techniques, ejection fraction <45%, ischemic heart disease, aortic valve disease, mitral annular calcification, and concomitant procedures other than surgical ablation or tricuspid repair/replacement. The durability of annuloplasty was assessed using longitudinal analysis of postoperative echocardiographic data. ResultsComplete ring annuloplasty was performed in 126 of 194 patients (65%); partial ring (posterior band) in the other 68 (35%). Concomitantly, 124 of the 194 patients underwent tricuspid valve surgery, and 173 (89%) had a procedure for AF, including biatrial Cox-Maze III/IV lesion set in 152 (88%) and pulmonary vein isolation in 21 (12%). All patients were discharged with no/trace MR. Freedom from moderate/severe MR after repair with annuloplasty alone was 89% at 10 years, and no significant differences were noted between complete and partial ring annuloplasty (early, P = .41; late, P = .92). Forty-eight percent of patients developed AF at 3 months or longer after surgery, and the presence of postoperative AF was not associated with a greater likelihood of recurrence of MR (P = .15). Freedom from mitral reintervention was 96% at 10 years. ConclusionsIn appropriate patients with AFMR, the long-term durability of annuloplasty is excellent with complete ring and posterior band annuloplasty techniques.

Quantum Cascade Laser Infrared Spectroscopy for Glycan Analysis of Glycoprotein Solutions.

Glycans are oligosaccharides attached to proteins or lipids and affect their functions, such as drug efficacy, structural contribution, metabolism, immunogenicity, and molecular recognition. Conventional glycosylation analysis has relied on destructive, slow, system-sensitive methods, including enzymatic reactions, chromatography, fluorescence labeling, and mass spectrometry. Herein, we propose quantum cascade laser (QCL) infrared (IR) spectroscopy as a rapid, nondestructive method to quantify glycans and their monosaccharide composition. Previously, we demonstrated high-sensitivity IR spectroscopy of protein solution using solvent absorption compensation (SAC) and double-beam modulation (DBM) techniques. However, the SAC-DBM approach suffered a limited frequency scanning range (<400 cm-1) due to the light dispersion by acousto-optic modulators (AOMs). Here, we implemented a mirror-based double-pass AOM in the SAC-DBM scheme and successfully extended the frequency range to (970 to 1840 cm-1), which encompasses the vibrational fingerprint of biomolecules. The extended frequency range allowed the simultaneous observation of monosaccharide ring bands (1000 to 1200 cm-1) and protein amide bands (1500 to 1700 cm-1). We compared the IR spectra of six glycoproteins and two nonglycosylated proteins with the results from intact mass spectrometry. The IR absorbance ratios of the ring band to the amide band of glycoproteins in solutions showed a linear correlation with the ratios of glycan to protein backbone masses. Furthermore, a multivariate analysis produced monosaccharide compositions consistent with the reported database for the glycoproteins, and the monosaccharide compositions were used to improve the predictability of the glycan-protein mass ratio from the IR-absorbance ratio. This nondestructive, high-sensitivity QCL-IR spectroscopy could be used as a standard method to monitor batch-to-batch comparability during drug manufacturing and quantify the glycosylation and monosaccharide composition of new glycoproteins and other glycosylated biosystems.

Rigid ring vs. flexible band for tricuspid valve repair in patients with tricuspid valve regurgitation: A systematic review and meta-analysis

Background & objectivesRigid ring and Flexible band are techniques used to repair tricuspid valve regurgitation. The comparison between both techniques' effectiveness is controversial in the literature. We conducted this systematic review and meta-analysis to compare the safety and efficacy of rigid ring versus flexible band for tricuspid valve repair in patients with tricuspid valve regurgitation. MethodsWe conducted a PRISMA-compliant systematic review and meta-analysis. A systematic search was performed in major databases, including PubMed, Scopus, Web of Science, and Cochrane CENTRAL to identify relevant published studies. Data were extracted and analyzed using Stata (version 17 for Mac) and Revman (version 5.4 for Windows). ResultsTwelve studies were included in this meta-analysis. Total number of patients was 4259. The rigid ring wasn't superior to the flexible band in terms of postoperative tricuspid regurgitation RR 0.74, 95 % CI (0.43–1.27) (P = 0.29). However, the results were not homogeneous. After employing sensitivity analysis, the significance of the pooled effect estimate didn't change, showing no significant difference between the two annuloplasty RR 0.72, 95%CI (0.45–1.15). On the other hand, the rigid ring was associated with a higher bypass time than the flexible band (RR 4.85, P = 0.00). There were no differences between the two groups in terms of hospital stay, ICU stays, prolonged ventilation, mechanical ventilation time, annuloplasty size, stroke, concomitant mitral valve surgery, concomitant aortic valve surgery, atrial fibrillation, pacemaker implantation, low cardiac output, in-hospital death, or late death (all P > 0.05). ConclusionOur study findings suggested no difference between rigid ring compared to flexible band regarding the rates of postoperative tricuspid regurgitation; however, rigid ring may encompass a higher bypass time. Therefore, further research is required to ensure our findings.

The effect of scalar hair on the charged black hole with the images from accretions disk

In this paper, we investigate the optical properties of a charged black hole with scalar hair (CSH) within the context of four-dimensional Einstein–Maxwell–Dilaton gravity. To achieve this, we consider three distinct toy models of thin accretion disks. The presence of dilaton coupling allows us to express both the solutions of CSH and the Reissner–Nordström (RN) black hole in terms of their mass (M) and charge (Q). Our findings reveal differences in the effective potentials Veff\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$V_{eff}$$\\end{document}, photon sphere radii rph\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$r_{ph}$$\\end{document}, and innermost stable circular orbit risco\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$r_{isco}$$\\end{document} between the CSH and RN black hole cases, which become increasingly pronounced as the charge parameter Q increases. However, no noticeable distinctions are observed concerning the critical impact parameter bph\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$b_{ph}$$\\end{document}. When the ratio of the photon ring band and the lensed ring band exceeds 0.1, it may suggest the presence of a charged black hole with scalar hair. Furthermore, our results underscore the significant influence of the charge parameter Q on the brightness distributions of the direct, lensed ring, and photon ring for three standard emission functions. These findings emphasize the potential for distinguishing between CSH and RN black holes through an analysis of direct intensity and peak brightness in specific accretion disk models.

Design and analysis of unequal aperture off-axis optical integrator for solar simulators.

The unequal aperture off-axis optical integrator design method is proposed to improve the irradiation uniformity of solar simulators and solve the problem of limited uniformity of optical integrator due to aberrations and uneven distribution of incident radiation. Firstly, the unequal aperture off-axis optical integrator structure is designed based on the scalar diffraction theory to analyze the factors affecting the optical homogenization ability of the optical integrator. Then, the relationship between sub-eye lens aperture and arrangement is explored in combination with Lagrange invariance principle and semi-definite programming theory. Finally, the optimum off-axis amount of sub-eye lens with different ring band is determined from the perspective of geometric optics by using the aberration theory and following the principle of edge light, so as to improve the evenness of optical integrator. The design results are verified by the simulation analysis. The simulation results show that: In the picture plane of optical integrator, the irradiation non-uniformity in the ф 26 mm irradiation plane is 14.87%, which is better than 26.02% in the traditional optical integrator. At the same time, at the effective irradiated surface, the irradiation non-uniformity of 0.53% within the ф 300 mm reaches the irradiation standard of the class A + solar simulator, and the irradiance only decreases by 16.5% compared with the traditional optical integrator, which still meets the index requirement of a solar constant. The goal of improving the evenness of optical integrator is realized without greatly affecting irradiance and without introducing aspherical design.

Структура та зміст програми корекційно-профілактичних заходів для офісних працівників із різним станом біомеханіки опорно-рухового апарату

Topicality. The harmful effect of the hypodynamic factor on a human body as a result of urbanization also consists in the strengthening of the spine morpho-functional deviations the significant number of children, adolescents and adults, progressing over the years and having adversely affects the reduction of work capacity, the possibility of full-time physical activities and sports. Among the various factors that cause diseases of the musculoskeletal system, in addition to physiological wear-and-tear, its functional overstrain, which is the cause of pathological changes, is of great importance. Pathological phenomena arising from tissue overloading of the musculoskeletal system are manifested in the form of hypoxia and hypoxemia, muscle hypertonicity, microcirculation disorders, and other abnormalities. The Research Purpose is to develop the structure and content of a corrective and preventive measures program for office workers with different biomechanics of musculoskeletal system. The Research Methods. Theoretical analysis of special scientific and methodical literature methods, pedagogical experiment have been used. The Research Results. For implementation the corrective and preventive measures and improving the office workers` musculoskeletal system, it is advisable to use a variety of exercises. While developing physical exercises program, the resarch has been focused on the generally accepted patterns of mature age men`s body development, the peculiarities of musculoskeletal functional disorders at this age and the development of physical qualities and physical exercises effect. A complex of exercises with equipment, in particular with an isotonic ring, short and long resistance bands, dumbbells, chips, as well as a roller for myofascial release has been suggested. Findings. The corrective and preventive measures aimed at increasing the level of functional capabilities of the musculoskeletal system and increasing the level of mature age men`s physical preparedness have been developed.

Melting Behaviors of Bio-Based Poly(propylene 2,5-furan dicarboxylate)-b-poly(ethylene glycol) Co Polymers Related to Their Crystal Morphology.

In this experiment, a series of poly(propylene 2,5-furan dicarboxylate)-b-poly(ethylene glycol) (PPFEG) copolymers with different ratios were synthesized using melt polycondensation of dimethylfuran-2,5-dicarboxylate (DMFD), 1,3-propanediol (PDO) and poly(ethylene glycol) (PEG). The effect of PEG content on the crystallization behavior of the poly(propylene 2,5-furan dicarboxylate) (PPF) copolymers was investigated. For PPF, the nucleation density of the β-crystals was higher than that of α-crystals. As Tc increases, the β crystals are suppressed more, but at Tc = 140 °C, the bulk of PPF has already been converted to α crystals, which crystallize faster at higher nucleation densities, resulting in a difference in polymer properties. For this case, we chose to add a soft segment material, PEG, which led to an early multi-melt crystallization behavior of the PPF. The addition of PEG led to a decrease in the crystallization temperature of PPF, as well as a decrease in the cold crystallization peak of PPF. From the crystalline morphology, it can be seen that the addition of PEG caused the transformation of the PPF crystalline form to occur earlier. From the crystalline morphology of PPF at 155 °C, it can be observed that the ring-banded spherical crystals of the PPF appear slowly with increasing time. With the addition of PEG, spherical crystals of the ring band appeared earlier, and even appeared first, and then disappeared slowly.

Kraft lignin from Jackfruit waste as an adsorbent for the selective recovery of biobutanol from the Acetone-Butanol-Ethanol fermentation broth

Lignin, a naturally occurring aromatic heteropolymer can be used for the selective recovery of biobutanol from fermented broth due to the presence of functional groups such as hydroxyl and carbonyl. In the present work, kraft lignin was extracted from Jackfruit (Artocarpus heterophyllus Lam) waste (JFW), characterized and tested for the selective recovery of butanol from model solutions and Acetone-Butanol-Ethanol (ABE) fermented broth by adsorption-desorption. Fourier Transform Infra-Red (FTIR) spectra of the extracted kraft lignin displayed characteristic bands of the aromatic rings and monomeric functional groups. X-ray diffraction (XRD) analysis demonstrated lignin diffraction peaks at 25° and 32°. Jackfruit waste kraft lignin recorded a high thermal decomposition temperature (Td) and glass transition temperature (Tg) of 180 °C and 145 °C denoting high thermal stability. Isotherm and kinetics experiments disclosed a maximum butanol adsorption capacity (Qmax) and equilibrium time of 214.59 mg/g and 55 min of Jackfruit waste kraft lignin. Ex-situ recovery of biobutanol from the Acetone-Butanol-Ethanol fermented broth using Jackfruit waste kraft lignin recorded a 25% increase in butanol titre compared with the initial solvent concentration in the broth. The present results confirm the selective adsorption of butanol by the isolated Jackfruit waste kraft lignin from the Acetone-Butanol-Ethanol fermented broth. Using lignin as an adsorbent to selectively recover biobutanol will solve the long-standing bottleneck of Acetone-Butanol-Ethanol fermentation.

Корекційно-профілактичні заходи для офісних працівників із функціональними порушеннями опорно-рухового апарату

Topicality. At the current stage of the society development, the number of men who work in the office at their computers is increasing significantly, which negatively affects their physical condition, in particular, the state of the biomechanics of the musculoskeletal system. The Objective of the Study is to develop measures aimed at prevention and correction of functional disorders of the musculoskeletal system of office workers. The following Methods were used to solve the tasks: theoretical analysis of special scientific and methodical literature, systematic synthesis. Results of the study. The Results of the theoretical analysis of modern research on this problem attest to the effectiveness of increasing the motor activity of people of mature age by means of physical education and sports. In the process of research, it was determined that for office workers with functional disorders of the biomechanics of posture, it is advisable to use fitness equipment. The results of the survey of office workers confirmed their desire to engage in health-improving fitness using modern trends. We suggest that for implementation of corrective and preventive measures in order to improve the condition of the musculoskeletal system of office workers, it is advisable to use a variety of exercises. We also suggest using exercises with equipment, in particular with an isotonic ring, short and long fitness rubber bands, dumbbells, chips, as well as a roller for myofascial release. To implement these means , we suggest using seven main types of patterns: Squat, Lanch, Hinge, Step, Twist, Push nf Pull. To implement the program, it is advisable to use circular training according to the 16-14-12-10-8-6 program and the Tabata protocol. Conclusions. The use of outlined health fitness means for the correction and prevention of functional disorders of the musculoskeletal system of office workers will contribute to the improvement of their physical development and working capacity.

Probing the Nano-Assembly Leading to Periodic Gratings in Poly(p-dioxanone).

This study used scanning electron microscopy via 3D dissection coupled with synchrotron radiation with microfocal beams of both small-angle X-ray scattering and wide-angle X-ray diffraction to analyze the periodic crystal aggregates of unusual poly(p-dioxanone) (PPDO) dendritic cactus-arm-like ring bands upon crystallization with a diluent poly(vinyl alcohol) (PVA) that is capable of hydrogen bonding interactions with PPDO. Three-dimensional microscopy interior dissection clearly expounds that the banded periodic architectures are packed by alternately normal-oriented flat-on crystals underneath the valley, periodically interfaced/branched with horizontal-oriented edge-on fibrils underneath the ridge. The oblique angles between the valley's flat-on crystals with the branches are ca. 25-45° (depending on gradient inclines and bending), which is also proved by the azimuthal angle in microbeam X-ray diffraction. The grating-like strut-rib assembly in the PPDO cactus-arm-like ring bands is further proved by novel iridescence tests.

Effect of carbon dioxide on lamellar arrangement in poly(lactic acid) ring band spherulites

AbstractIn this research, the formation of ring band spherulite of poly(lactic acid) (PLA) under carbon dioxide (CO2) was in‐situ studied and the internal lamellar arrangement of ring band spherulite formed under CO2 was revealed for the first time. The spherulites by PLA crystallized under air and different CO2 pressures have been studied, and the surface and internal lamellar arrangement of the ring band spherulites have also been analyzed in detail. It was found that PLA would form ring band spherulite under air and 6 MPa CO2, while the internal structures of the two types of ring band spherulites were different. The surface height difference of ring band spherulites formed under air was small, at 278.9 nm, and the twisting angle of the lamellae was also small. However, the difference in the surface height of the ring band spherulite formed under 6 MPa CO2 was big, reaching 778.3 nm. Through analysis on the internal lamellar arrangement of the ring band spherulite, it was found that the valley for the ring band spherulites formed under 6 MPa CO2 was composed of flat‐on lamellae, the ridge was composed of edge‐on lamellae and the sudden twist occurred between the flat‐on lamellae and edge‐on lamellae.

Evaluation of the Effect of Pb Pollution on Avian Influenza Virus-Specific Antibody Production in Black-Headed Gulls (Chroicocephalus ridibundus).

Lead (Pb), an environmental pollutant, has been widely reported to have contaminated mammals, including humans and birds. This study focuses on the effects of Pb pollution on avian influenza virus (AIV) antibody production. A total of 170 black-headed gulls (Chroicocephalus ridibundus) were captured in Tokyo Bay (TBP) from January 2019 to April 2020 and in Mikawa Bay (MBP) from November 2019 to April 2021. The gulls were weighed, subjected to blood sampling, and released with a ring band on their tarsus. The samples were used to measure blood Pb levels (BLL) and AIV-specific antibodies. The BLL were compared using the Wilcoxon two-sample test between the period when black-headed gulls arrived and the wintering period, defined by the number of gulls counted in each area. A significant increase was found in the TBP. A decrease in BLL significantly increased antibody titer during wintering in TBP and MBP. Pb pollution had a negative effect on the production of AIV antibodies. These findings suggest that wild birds that were contaminated by Pb in the environment may facilitate the spread of zoonotic diseases, further increasing the possibility that environmental pollutants may threaten human health.

Comparative study of tricuspid valve repair using ring vs. synthetic band in severe functional tricuspid valve regurgitation

Background: Functional tricuspid valve regurgitation secondary to left-sided valve disease remains a common problem. There are different surgical techniques for tricuspid valve repair; however, the superiority of one approach over the other has not been proven. Our objective was to compare the short-term results of ring versus synthetic band annuloplasty to repair functional severe tricuspid regurgitation in patients with left-sided valve lesions.&#x0D; Methods: This retrospective study includes 60 patients who underwent left-sided valve replacement with concomitant tricuspid valve repair for severe tricuspid regurgitation. Patients were divided into group A (n= 30), patients with rigid rings, and group B (n= 30), patients with synthetic bands.&#x0D; Results: The preoperative demographic and clinical data were non-significant between both groups. In the preoperative data, the tricuspid annular plane systolic excursion (TAPSE) was significantly higher in the ring group (2.84 ± 0.53 vs. 2.3 ± 0.4, P&lt; 0.001). Hospital stay was more prolonged in group B (10.05 ± 1.57 vs. 11.7 ± 2.76 days, P=0.006). There were no differences in other operative and postoperative data between groups. After a six-month follow-up, both groups had no significant difference regarding the clinical data or the degree of tricuspid valve regurgitation.&#x0D; Conclusion: Tricuspid valve annuloplasty with a rigid ring or synthetic band for tricuspid regurgitation could have a good short-term outcome.

Local super-resolution imaging of foveated areas in super-oscillating optical fields.

Herein, we propose a super-oscillation optical field foveated local super-resolution imaging method. Firstly, the post-diffraction integral equation of the foveated modulation device is constructed, the objective function and constraints are established, and the structural parameters of the amplitude modulation device are optimally solved by using genetic algorithm. Secondly, the solved data have been input into the software for point diffusion function analysis. We have studied the super-resolution performance of different ring band amplitude types, and find the 8-ring 0-1 amplitude type has the best super-resolution performance. Finally, the principle experimental device is built according to the simulation parameters, and the super-oscillatory device parameters is loaded onto the amplitude type spatial light modulator for the principle experiments, in which the super-oscillation foveated local super-resolution imaging system is able to perform high image contrast imaging in the whole field of view and super-resolution imaging in the foveated field of view area. As a result, this method achieves the 1.25 times super-resolution magnification in the foveated field of view area, which realizes the super-resolutio n imaging of local field while keeping the resolution of other fields unchanged. Experiments verify the feasibility and effectiveness of our system.

Laser Radar Data Registration Algorithm Based on DBSCAN Clustering

At present, the core of lidar data registration algorithms depends on search correspondence, which has become the core factor limiting the performance of this kind of algorithm. For point-based algorithms, the data coincidence rate is too low, and for line-based algorithms, the method of searching the correspondence is too complex and unstable. In this paper, a laser radar data registration algorithm based on DBSCAN (Density-Based Spatial Clustering of Applications with Noise) clustering is proposed, which avoids the search and establishment of the corresponding relationship. Firstly, a ring band filter is designed to process the outliers with noise in a point cloud. Then, the adaptive threshold is used to extract the line segment features in the laser radar point cloud. For the point cloud to be registered, a DBSCAN density clustering algorithm is used to obtain the key clusters of the rotation angle and translation matrix. In order to evaluate the similarity of the two frames of the point cloud in the key clusters after data registration, a kernel density estimation method is proposed to describe the registered point cloud, and K-L divergence is used to find the optimal value in the key clusters. The experimental results show that the proposed algorithm avoids the direct search of the correspondence between points or lines in complex scenes with many outliers in laser point clouds, which can effectively improve the robustness of the algorithm and suppress the influence of outliers on the algorithm. The relative error between the registration result and the actual value is within 10%, and the accuracy is better than the ICP algorithm.

Light Source Optimization of 3D Inner Contour Measurement System Based on Ring Beam Method

Ring beam method is a simple and efficient method for measuring three-dimensional internal contour. The whole three-dimensional inner contour is stitched from the contour lines of cross-sectional images collected during scanning. The contour image with uniform and moderate light intensity and fine ring band is beneficial to the calculation of contour line extraction algorithm. In practice, due to the quality of the ring beam and the modulation effect of the sample surface microstructure, the light band of the contour image has local widening, overexposure and speckle phenomena, which directly affect the contour extraction effect. The ring beam generation system is optimized here, which makes the whole system have better size adaptability and convenient adjustment. In addition, experiments results show that the measurement repeatability of the cross-sectional profile obtained after the light source optimization has been effectively improved.

Microscopic and Small-/Wide-Angle Microbeam X-ray Analyses on Dendritic Crystals in Poly(butylene succinate)

A unique composite dendritic spherulite is detected in a specific crystallization temperature range (Tc = 60–78 °C), whose assembly is probed using microscopy techniques and powerful synchrotron X-ray microbeam analyses. Composite dendritic spherulites composed of feather-like and fern-like branches in poly(butylene succinate) (PBSu) crystallized with poly(ethylene oxide) diluent are analyzed on top surface morphologies correlating with interior-dissected assembly, concurrently through polarized-light optical microscopy, scanning electron microscopy, and synchrotron-radiation X-ray microbeam analysis. The feather-like branch is composed of fully edge-on crystal plates, while the fern-like branch is composed of flat-on crystal plates. These branches originate from a common nucleus with different growth rates. For the first time, the dendritic PBSu spherulite serves as a convenient model for understanding the mechanisms how edge-on and flat-on crystal orientations can alternate not only in a serial mode to form ring bands but also in a parallel mode to form straight dendrites. Morphology evidence and detailed microbeam techniques collectively prove that these discontinuous lamellar plates discretely and gradually tilt and bend to transform from a vertical to a horizontal crystal plate with a corresponding alteration in birefringence.

Crystal-by-Crystal Assembly in Two Types of Periodically Banded Aggregates of Poly(p-Dioxanone).

The exterior and interior lamellar assemblies of poly(p-dioxanone) (PPDO) crystallized at 76 °C yield the most regular ones to interpret the 3D assembly mechanisms and potential for structural coloration iridescence, which are investigated using atomic-force microscopy (AFM), and scanning electron microscopy (SEM). PPDO displays two types of ring-banded spherulites within a range of Tc with dual-type birefringent spherulites (positive and negative-type) only within a narrow range of Tcs = 70−78 °C. At Tc > 80 °C, the inter-band spacing decreases from a maximum and the crystal assembly becomes irregularly corrupted and loses the capacity for light interference. Periodic grating assemblies are probed by in-depth 3D dissection into periodically banded crystal aggregates of poly(p-dioxanone) (PPDO) to disclose such layered gratings possessing iridescence features similar to nature’s structural coloration. This work amply demonstrates that grating assembly by orderly stacked crystal layers is feasible not only for accounting for the periodic birefringent ring bands with polarized light but also the distinct iridescence by interfering with white light.