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oe1(光电查) - 科学论文

62 条数据
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  • High-speed Fizeau interferometry for film topography measurement during spray film interaction

    摘要： This work presents a novel high-speed interferometric thickness measurement system for thin films (1 μm-23 μm). The system is based on a Fizeau-interferometer and combines a high-speed camera for 2-D topographic fringe images with a spectrally resolved white light interferometer. The aim of this combination is to overcome the ambiguities of the phase demodulation process during fringe pattern analysis. The system is able to measure spatially and temporally resolved film thickness distributions during fast processes. The measurement error of the system is around 5% compared to a commercial 0-D interferometer. First, the results during a diesel spray impingement onto a predefined diesel film are shown, and at the impingement point, an increase in a fluid volume of 24.3% can be seen.

    关键词： interferometric thickness measurement,High-speed Fizeau interferometry,thin films,spray film interaction,film topography measurement

    更新于2025-09-10 09:29:36

  • Does Dry Eye Affect Repeatability of Corneal Topography Measurements?

    摘要： Objectives: The purpose of this study was to assess the repeatability of corneal topography measurements in dry eye patients and healthy controls. Materials and Methods: Participants underwent consecutive corneal topography measurements (Sirius; Costruzione Strumenti Oftalmici, Florence, Italy). Two images with acquisition quality higher than 90% were accepted. The following parameters were evaluated: minimum and central corneal thickness, aqueous depth, apex curvature, anterior chamber volume, horizontal anterior chamber diameter, iridocorneal angle, cornea volume, and average simulated keratometry. Repeatability was assessed by calculating intra-class correlation coefficient. Results: Thirty-three patients with dry eye syndrome and 40 healthy controls were enrolled to the study. The groups were similar in terms of age (39 [18-65] vs. 30.5 [18-65] years, p=0.198) and gender (M/F: 4/29 vs. 8/32, p=0.366). Intra-class correlation coefficients among all topography parameters within both groups showed excellent repeatability (>0.90). Conclusion: The anterior segment measurements provided by the Sirius corneal topography system were highly repeatable for dry eye patients and are sufficiently reliable for clinical practice and research.

    关键词： repeatability,Dry eye,corneal topography

    更新于2025-09-09 09:28:46

  • [IEEE 2018 IEEE International Interconnect Technology Conference (IITC) - Santa Clara, CA, USA (2018.6.4-2018.6.7)] 2018 IEEE International Interconnect Technology Conference (IITC) - Modulation of Within-Wafer and Within-die Topography for Damascene Copper in Advanced Technology

    摘要： A novel copper electroplating and CMP process was developed to effectively modulate the within-wafer and within-die nanoscale topography. The feasibility of this new metallization is demonstrated on a 64nm pitch product with an equivalent defect in resistance and trench height. It’s believed to be extendable to other advanced nodes for a sizable reduction in copper overburden which saves CMP polish cycle time from the plan-of-record time. lower and tighter distribution level, uniformity improvement as well as substantial overburden thickness reduction as will be described in this paper.

    关键词： within-die non-uniformity,topography,Cu CMP,Copper damascene plating

    更新于2025-09-09 09:28:46

  • Caveats to Obtaining Retinal Topography With Optical Coherence Tomography

    摘要： We read with great interest the article by Oh et al.1 on the assessment of retinal topography in myopic eyes using spectral domain optical coherence tomography (SD-OCT). In their article, the investigators described different characteristics of retinal topography to indicate variations in ocular shape in myopia (such as a retina sloped nasally versus temporally). Like similar prior studies using magnetic resonance imaging (MRI) to measure posterior eye shape in myopia, we agree this work in retinal topography provides important insight into classifying and risk stratifying myopic eyes. However, we would like to highlight a misconception regarding the use of posterior segment SD-OCT images for absolute retinal topography measurements. In the Discussion section, it is stated that 'The rainbow pseudo-colors in the topographic (RPE) layer image represent height from the coronal plane of the eye, with blue indicating low height and red indicating high height.' In OCT, the reference plane is not the coronal plane or any plane within the eye. Instead, the reference plane is a reference delay path length in the OCT device itself.2 Axial distance (height) within an OCT image represents sample distances relative to that reference delay in optical path length. Therefore, because the reference is in the OCT device and not in the eye itself, how the eye is positioned relative to the OCT device affects the eye’s appearance in the OCT image. For example, all three distinct subtypes of retinal sloping described in the article (nasal, middle, and temporal) can be produced from the same eye simply by moving the OCT scan beam position in the pupil slightly relative to the pupil center (see Figure). The same effect also would occur if, conversely, the subject’s eye moved relative to the OCT device. Further, OCT images of the posterior eye are distorted by scan geometry and optical artifacts as our group and others have described previously.3–5 The cumulative effect is that an OCT image of the posterior eye is not an exact spatial replica or digital 'cast' of the eye itself. Hence, when using OCT to measure the absolute topography of the posterior eye, these imaging effects must be considered to separate them from actual topographic differences present in these myopic eyes.

    关键词： retinal topography,posterior eye shape,myopia,optical coherence tomography,imaging artifacts

    更新于2025-09-09 09:28:46

  • High-resolution imaging of distinct human corpus callosum microstructure and topography of structural connectivity to cortices at high field

    摘要： Characterization of the microstructural properties and topography of the human corpus callosum (CC) is key to understanding interhemispheric neural communication and brain function. In this work, we tested the hypothesis that high-resolution T1 relaxometry at high field has adequate sensitivity and specificity for characterizing microstructural properties of the human CC, and elucidating the structural connectivity of the callosal fibers to the cortices of origin. The high-resolution parametric T1 images acquired from healthy subjects (N = 16) at 7 T clearly showed a consistent T1 distribution among individuals with substantial variation along the human CC axis, which is highly similar to the spatial patterns of myelin density and myelinated axon size based on the histology study. Compared to the anterior part of the CC, the posterior midbody and splenium had significantly higher T1 values. In conjunction with T1-based classification method, the splenial T1 values were decoded more reliably compared to a conventional partitioning method, showing a much higher T1 value in the inferior splenium than in the middle/superior splenium. Moreover, the T1 profile of the callosal subdivision represented the topology of the fiber connectivity to the projected cortical regions: the fibers in the posterior midbody and inferior splenium with a higher T1 (inferring a larger axon size) were mainly connected to motor–sensory and visual cortical areas, respectively; in contrast, the fibers in the anterior/posterior CC with a lower T1 (inferring a smaller axon size) were primarily connected to the frontal/parietal–temporal areas. These findings indicate that high-resolution T1 relaxometry imaging could provide a complementary and robust neuroimaging tool, useful for exploring the complex tissue properties and topographic organization of the human corpus callosum.

    关键词： Myelin density,Structural connectivity,Topography,Parametric T1 MRI,Corpus callosum,Axon size

    更新于2025-09-09 09:28:46

  • Effects of N2 and NH3 plasma exposure on the surface topography of p-GaN under quasi-atmospheric pressure

    摘要： We used atomic force microscopy to characterize the surface topography of p-GaN exposed to N2 and NH3 plasma under quasi-atmospheric pressure using a microwave-excited plasma source with a microstrip line structure. The exposure time was varied from 2 to 20 min at a substrate temperature of 700 °C. Under both N2 and NH3 plasma exposure for 2 min, the ridge-shaped features on the surface of as-grown p-GaN dulled immediately and the surface roughness decreased remarkably, whereas the atomic step structure of the surface was maintained. The step crossing and bunching of the surface disappeared with increasing exposure time to both types of plasma. However, increasing the NH3 plasma exposure time to 20 min led to the formation of pits and appearance of particles along the step edges, resulting in drastic roughening of the surface. Thus, GaN surfaces can be smoothed without the destruction of their step structures via moderate plasma exposure under quasi-atmospheric pressure, and these plasma sources could prospectively be used in metal-organic chemical vapor deposition systems for nitride semiconductor growth.

    关键词： microwave-assisted plasma,surface topography,N2 and NH3 plasma,atomic force microscopy,metal organic chemical vapor deposition,GaN

    更新于2025-09-09 09:28:46

  • Optic disc topography in Malay patients with normal-tension glaucoma and primary open-angle glaucoma

    摘要： Background: There are limited data concerning the optic disc topography in normal-tension glaucoma (NTG) and primary open-angle glaucoma (POAG) patients living in Southeast Asian countries. This study aims to compare optic disc parameters in patients with NTG and POAG in Malaysia and to discuss the results in comparison with studies of NTG and POAG in other Asian countries. Methods: This prospective cross-sectional study was performed in two hospitals with glaucoma service in Malaysia from 2010 to 2012. Seventy-seven patients of Malay ethnicity were enrolled in this study, including 32 NTG patients and 45 POAG patients. Using the Heidelberg Retinal Tomograph III, we measured optic disc area, cup area, rim area, cup volume, rim volume, cup-to-disc area ratio, mean cup depth, maximum cup depth, cup shape measure, height variation contour, mean retinal nerve fiber layer thickness, and retinal nerve fiber layer cross-sectional area. Results: The eyes for NTG patients had significantly larger optic disc areas (2.65 [standard deviation, 0.41] vs 2.40 [standard deviation, 0.36] mm2, respectively; P=0.006) and cup areas (1.54 [standard deviation, 0.43] vs 1.32 [standard deviation, 0.40] mm2, respectively; P=0.027) compared with the eyes of POAG patients. Comparison of the other parameters between the two groups revealed no significant difference (P0.050). The moderate and severe NTG patients showed significantly deeper cups and larger disc and cup areas when compared with the moderate and severe POAG patients (P0.050). Conclusion: The NTG patients in this study have notably larger optic disc and cup areas than the POAG patients. Our observations are consistent with those reported in studies of NTG and POAG patients in Korea. The deeper cups and larger disc and cup areas may serve as indicators of severity when comparing NTG with POAG. However, these findings require verification with IOP and visual field results.

    关键词： optic disc topography,primary open-angle glaucoma,Heidelberg Retina Topography III,Malay ethnicity,normal-tension glaucoma

    更新于2025-09-04 15:30:14

  • Photoluminescence Imaging for Buried Defects Detection in Silicon: Assessment and Use-cases

    摘要： In this work, the innovative photoluminescence imaging technique is described for applications to buried defect detection in silicon devices. The validity of this emerging technique is first assessed in comparison with well-established characterization techniques (defect selective etching of silicon, X-Ray diffraction topography, cross-sectional transmission electron microscopy imaging and photoluminescence spectroscopy). The paper then describes specific applications illustrating the use of the photoluminescence imaging technique for common processes of the CMOS semiconductor industry. The benefit of this fast, high resolution and non-destructive technique is demonstrated: this includes industrial use of the technique for in-line production control on product wafers.

    关键词： photoluminescence imaging,dislocations,non-visual defects,X-Ray diffraction topography,photoluminescence spectroscopy,buried defects

    更新于2025-09-04 15:30:14

  • [IEEE 2018 IEEE International Conference on Semiconductor Electronics (ICSE) - Kuala Lumpur (2018.8.15-2018.8.17)] 2018 IEEE International Conference on Semiconductor Electronics (ICSE) - A Study on the Atomic Topography of Nanostructured TiO<inf>2</inf>Thin Films: Effect of Annealing

    摘要： Titanium dioxide (TiO2) is one of the most investigated metal oxides due to the wide range of applications such as photocatalysts. Photocatalytic activity will increased when the surface area is higher. Hence, this research focus on the surface topography and roughness of nanostructured TiO2 films characterized by atomic force microscopy (AFM) in order to obtain thin films with the optimum roughness for photocatalytic activity. TiO2 thin films were prepared by spin coating method at room temperature. The TiO2 solutions of 0.1 - 0.2 M were synthesized from titanium butoxide in ethanol. TiO2 films were deposited on the silicon substrates and annealed at 450°C. The results shown when the film was annealed, the grain were clearly observed. The grain size and the roughness increased when the film were annealed at high temperature. 0.2 M of TiO2 thin film exhibit the higher roughness with Ra and RMS values were 51.29 and 78.90 nm, respectively.

    关键词： Molarity,Roughness,TiO2,Topography,AFM

    更新于2025-09-04 15:30:14

  • Dynamically evolving surface patterns through light-triggered wrinkling erasure

    摘要： For many applications, it is an imperative that changes in polymer surface topography, especially periodic patterns, can be triggered on command by a well-defined remote signal. In this contribution, we report a light-induced cascade of changes in wrinkling wavelengths on thin polymer layers supported by an elastomeric substrate under tensile stress. Through the applied supramolecular design, the effect of varying the ratio of light active and light passive components can be easily assessed, and it is shown that both the cascade type as well as the rate of the progress of the dynamic light-induced changes can be tuned by this ratio, as well as by the light intensity. Furthermore, for the reported phenomena to occur, nominally only every 20th polymer repeat unit needs to be occupied by a chromophore, which makes the conversion of the sub-nm photoisomerization reaction into 10 μm - scale changes of periodic surface patterns extremely efficient.

    关键词： light-triggered wrinkling erasure,polymer surface topography,photoisomerization,supramolecular design,elastomeric substrate

    更新于2025-09-04 15:30:14