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Effects of source/drain-electrode material, thickness and fabrication method on the electrical performance of pentacene thin-film transistor
摘要： The e?ects of source/drain (S/D) electrode material (Ni, Pt and Pd) and deposition method (electron-beam evaporation and sputtering) on the performance of pentacene organic thin-?lm transistor (OTFT) are studied. Experimental results show that the OTFT with Pd S/D electrodes deposited by sputtering exhibits the best electrical performance. This should be due to the small charge-injection barrier at the pentacene/electrode interface and small thermal load generated during the metal deposition. Besides, through varying the Pd S/D electrode thickness, it is found that increasing the electrode thickness results in performance degradation due to degraded pentacene/electrode interface, which is caused by higher thermal stress developed during longer deposition time.
关键词： Organic thin-?lm transistor,Contact metal,Electrode thickness,Fabrication method
更新于2025-09-10 09:29:36
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A comparison of NCT, Goldman application tonometry values with and without fluorescein
摘要： Purpose: The aim of the study was to statistically compare intraocular pressure (IOP) values measured using noncontact tonometer (NCT), Goldmann applanation tonometry (GAT) with fluorescein (fGAT), and GAT without fluorescein (nGAT). The study was also performed to test whether the values obtained using each technique change in accordance with the central corneal thickness (CCT) and refractive and keratometric values. Study design: This study was a prospective study of 188 eyes of 94 healthy volunteers. Methods: IOP was measured using fGAT, nGAT and NCT. CCT, refractive values, and keratometric values were measured, and the correlations and differences in the IOP for each tonometer were investigated. Results: The mean IOP values obtained with the NCT, nGAT, and fGAT were 17.5±3.7, 12.3±2.7, and 12.5±2 mmHg. The mean CCT was 538.2±34.4 μm, the mean refractive value was 0.9±1.2 D, and the mean keratometric value was 43.5±1.5 D. NCT was positively correlated with fGAT and GAT values and was significantly higher than both the values. There were no differences between fGAT and GAT values. No correlation was observed between the CCT and keratometric and refractive values and the difference between NCT and nGAT or fGAT. Conclusion: Differences in the measurements obtained using nGAT and fGAT were insignificant (P.0.05). Both values were positively correlated with NCT measurements (r =0.354, P,0.05) and were independent of CCT, keratometry, and refraction values. nGAT appears to be suitable for use in routine clinic practice.
关键词： central corneal thickness,Goldmann applanation tonometry,intraocular pressure,refractive value,noncontact tonometry,fluorescein
更新于2025-09-09 09:28:46
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In Vivo Quantification of Retinal Changes Associated With Drusen in Age-Related Macular Degeneration
摘要： PURPOSE. Drusen alters retinal architecture in early age-related macular degeneration (AMD). However, abnormalities also may exist in drusen-free areas of the AMD retina. This study examines retinal thickness above drusen relative to drusen-free areas in the same patient and a normal population. METHODS. Patients with early to intermediate AMD (n ? 122) or no disease (n ? 30) were examined at the Center for Eye Health. Spectral domain optical coherence tomography (SD-OCT) scans through single, isolated druse (n ? 125) or con?uent drusen (n ? 54) were obtained. The thickness of individual retinal layers was measured above the druse and in a drusen-free area, 150 lm from the drusen edge. RESULTS. Intraeye comparisons found total retinal thickness above drusen was 16 6 0.6% less than drusen-free areas. Thinning was mostly in the retinal pigment epithelium/photoreceptor layer (32 6 1% reduction) and the outer nuclear layer (22 6 1% reduction). Con?uent drusen showed similar thinning of the outer retina as well as inner retina loss (5%). Thinning was strongly correlated with drusen height, but only modestly correlated with drusen width. When compared to the normal population, retinal thickness above drusen and drusen-free areas were signi?cantly reduced. CONCLUSIONS. We con?rm outer retina thinning above drusen in early/intermediate AMD compared to drusen-free areas in the same retina or a normal population. Interestingly, drusen-free areas in AMD patients were not the same as control patients suggesting ‘‘normal’’ areas of the AMD retina are abnormal. The strong correlation between retinal thinning and drusen height, rather than width, suggests current grading systems for AMD may need re?nement.
关键词： drusen,age-related macular degeneration,optical coherence tomography,retinal thickness
更新于2025-09-09 09:28:46
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Parameters of ocular fundus on spectral-domain optical coherence tomography for glaucoma diagnosis
摘要： In this review, we summarize the progression of several parameters assessed by spectral-domain optical coherence tomography (SD-OCT) in recent years for the detection of glaucoma. Monitoring the progression of defects in the retinal nerve fiber layer (RNFL) thickness is essential. Imaging and analysis of retinal ganglion cells (RGCs) and inner plexiform layer (IPL), respectively, have been of great importance. Optic nerve head (ONH) topography obtained from 3D SD-OCT images is another crucial step. Other important assessments involve locating the Bruch’s membrane opening (BMO), estimating the optic disc size and rim area, and measuring the lamina cribrosa displacement. Still other parameters found in the past three years for glaucoma diagnosis comprise central retinal artery resistive index, optic disc perfusion in optical coherence tomography angiography (OCTA) study, peripapillary choroidal thickness, and choroidal area in SD-OCT. Recently, several more ocular fundus parameters have been found, and compared with the earlier parameters to judge the accuracy of diagnosis. While a few of these parameters have been widely used in clinical practice, a fair number are still in the experimental stage.
关键词： optic nerve head,retinal nerve fiber layer,lamina cribrosa,optical coherence tomography,macular thickness,ganglion cells,glaucoma progression
更新于2025-09-09 09:28:46
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Comparison of keratometric and pachymetric parameters with Scheimpflug imaging in normal and keratoconic Asian eyes
摘要： Purpose: To evaluate the keratometric and pachymetric parameters of keratoconic corneas of Asian eyes with the Scheimpflug imaging camera. Patients and methods: This is a cross-sectional study of 22 eyes with Amsler-Krumeich stage 1 keratoconus and 48 eyes from normal subjects conducted in a tertiary eye hospital. A rotating Scheimpflug imaging system, the Pentacam, was used to evaluate all eyes for tomographic parameters, as well as pachymetric progression indices (PPI) and Ambrósio relational thickness (ART). Results: All PPI and ART parameter values were significantly different between study and control groups. Cornea minimum radius of curvature, absolute distance from corneal apex to thinnest location, as well as the distance from corneal apex to thinnest location in Y-axis also demonstrated statistically significant differences. The mean ART values for keratoconus eyes were 241 μm (ART-maximum) and 352 μm (ART-average), falling within previously reported best cutoff values for detecting keratoconus. On receiver operating characteristics curve analysis, the area under the curve values were highest for PPI and ART parameters. Conclusion: There are significant differences in tomographic parameters between stage 1 keratoconic and normal Asian eyes. Pachymetric indices such as the PPI and the ART index can serve as additional tools in differentiating keratoconic from normal eyes. The findings validate the usefulness of the ART in identifying keratoconic eyes in Asians.
关键词： corneal tomography,keratoconus,pentacam,Ambrósio relational thickness
更新于2025-09-09 09:28:46
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Resonator-Inspired Metamaterial Sensor: Design and Experimental Validation for Measuring Thickness of Multi-Layered Structures
摘要： A digit 8-shaped resonator inspired metamaterial is proposed herein for sensor applications. The resonator is surrounded by a ground frame and excited by a microstrip feedline. The measurement of the sensor can be performed using common laboratory facilities in lieu of using the waveguide, as the resonator, ground frame, and feedline are all on the same microstrip. To achieve metamaterial properties, more than one unit cell is usually utilized, whereas, in this work, a single cell was used to achieve the metamaterial characteristics. The properties of the metamaterial were investigated to find the relationship between the simulation and measurements. The proposed metamaterial sensor shows considerable sensitivity in sensor application. For the sensor application, FR4 and Rogers RO4350 materials were used as the over-layer. The sensor can measure dielectric thickness with a sensitivity of 625 MHz/mm, 468 MHz/mm, and 354 MHz/mm for the single over-layer, double over-layers, and multiple over-layers, respectively. The proposed prototype can be utilized in several applications where metamaterial characteristics are required.
关键词： metamaterial sensor,sensitivity,resonator,thickness
更新于2025-09-09 09:28:46
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Comparison of Anterior Segment Measurements between Scheimpflug Camera and New Module of Optical Coherence Tomography
摘要： Purpose: We compared the anterior segment measurements using a Scheimpflug camera (Pentacam? [Oculus Inc., Wetzlar, Germany]) and a new anterior segment module of optical coherence tomography (Cirrus HD-OCT 5000? [Carl Zeiss Meditec, Dublin, CA, USA]). Methods: Anterior segment measurements were evaluated in 47 eyes of 26 patients who visited for the purpose of cataract surgery. Measurements of the central corneal thickness (CCT), anterior chamber depth (ACD), anterior chamber angle (ACA; nasal and temporal side), and angle to angle distance (ATA) were compared between the Pentacam? and the new anterior segment module of the Cirrus HD-OCT 5000?. Results: The mean CCTs measured by the Pentacam? and the new anterior segment module of the Cirrus HD-OCT 5000? were 561.68 ± 31.35 μm and 559.04 ± 36.43 μm, respectively. There was no statistically significant difference (p = 0.387) and high correlations in the results using the two methods (r = 0.824, p < 0.001). The mean ACD measurements using the Pentacam? and Cirrus HD-OCT 5000? were 2.70 ± 0.44 mm and 2.68 ± 0.42 mm, respectively. The measurements were strongly correlated (r = 0.981, p < 0.001) without a statistically significant difference (p = 0.091). The measurements of ACA (nasal and temporal side) and ATA did not differ significantly different between the two methods (p = 0.109, p = 0.153, p = 0.322, respectively). High correlations were observed between the two methods (r = 0.944, r = 0.951, r = 0.955, respectively; p < 0.001 in all groups). Conclusions: There was no significant difference between the CCT, ACD, ACA, and ATA measured by the Pentacam? and the new anterior segment module of the Cirrus HD-OCT 5000? in adult patients. However, there was a low degree of agreement for the CCT. The measurements of ACD, ACA, and ATA can therefore be considered interchangeable when used clinically.
关键词： Pentacam?,Anterior chamber depth,Cirrus HD-OCT?,Anterior chamber angle,Central corneal thickness
更新于2025-09-09 09:28:46
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The effects of ranibizumab injections on fluorescein angiographic findings and visual acuity recovery in age-related macular degeneration
摘要： The objective of the study reported here was to evaluate the effect of ranibizumab on retinal circulation times and vessel caliber and to analyze the correlation of these factors with visual acuity (VA) prognosis in patients with age-related macular degeneration (AMD).
关键词： central macular thickness,prognosis,retinal arteriole diameter,vessel caliber,retinal vein diameter
更新于2025-09-09 09:28:46
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A METHOD FOR ICE-THICKNESS DETECTING AND ICE-SECTION IMAGING BY USING FMCW-SAR ALGORITHM
摘要： Sea ice plays an important role in global climate. Many researches focus on the measurement of the sea ice thickness. In this paper, we present a method for the ice-detecting combining frequency-modulated continuous-wave (FMCW) technology and synthetic aperture radar (SAR) technology. It can provide a good resolution both in the range dimension and the azimuth one. Then a simulation is conducted to verify the accuracy and the feasibility of this algorithm. The physical properties of the sea ice, such as re?ection and scatter properties of the ice surface and the transmission characteristic when the electromagnetic wave travels through the ice, are considered in the simulation. The results of the simulation demonstrate that this algorithm has a good performance in ice penetrating.
关键词： FMCW-SAR,simulation,ice thickness detection,sea ice
更新于2025-09-09 09:28:46
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Effect of the Active Channel Thickness Variation in Amorphous In–Zn–Sn–O Thin Film Transistor
摘要： Ternary oxide thin films in the In2O3–ZnO–SnO2 system were studied for potential applications in oxide semiconductor thin film transistors (TFTs). An amorphous In–Zn–Sn–O (a-IZTO) active channel layer was deposited by RF magnetron sputtering at room temperature on an n++ Si substrate. Films from a sintered ceramic target with a nominal chemical composition of In:Zn:Sn = 40:50:10 at.% were prepared with thicknesses ranging from 15 nm to 150 nm, which was followed by annealing at 350 °C for 30 minutes in air. Subsequently, a bilayer Cu/Ti metal contact was deposited as the source/drain electrodes on the top surface through a shadow mask using an e-beam evaporator. The thickness of the active channel layer greatly influenced the characteristics of the oxide thin film transistors. The best transistor characteristics were observed from the test device with a channel thickness of 30 nm and a high on/off current ratio of approximately 108, high field effect mobility of 25 cm2/Vs, low threshold voltage of ?0.1 V, and very small subthreshold swing of 0.14 V/dec.
关键词： Thin Film Transistor,In–Zn–Sn–O,Amorphous Oxide,RF Magnetron Sputtering,IZTO,Channel Thickness
更新于2025-09-09 09:28:46