scholarly journals Highly Stable All-Fiber-Ring Short-Cavity Continuously Tuned Swept Source

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 328
Author(s):  
Zhiwei Yang ◽  
Xu Wu ◽  
Deqin Ouyang ◽  
Huibin Sun ◽  
Shuangchen Ruan
Keyword(s):  
Numerical Simulation ◽  
Optical Coherence Tomography ◽  
Spectral Width ◽  
Output Spectrum ◽  
Fiber Ring ◽  
Swept Source ◽  
Central Wavelength ◽  
Simulation Results ◽  
Oct Imaging ◽  
The Stability

In this study, we present a swept source that can intelligently control its sweeping speed while satisfying the commercial stability and miniaturization standards. The source’s central wavelength of the output spectrum is 1300 nm and spectral width is greater than 100 nm. Meanwhile, the scan frequency can be adjusted to range from 20 to 100 kHz, and the stability degree of the optical capacity is less than 0.34%. Additionally, this study establishes a numerical model for the swept-source optical coherence tomography (SS–OCT) system and introduces a numerical simulation of the signal produced during the OCT imaging process. The simulation results are helpful to guide the design and construction of the future OCT systems.

Feasibility and Clinical Utility of Ultra-Widefield–Navigated Swept-Source Optical Coherence Tomography Imaging

2021 ◽  
pp. 247412642199733
Author(s):  
Kyle D. Kovacs ◽  
M. Abdallah Mahrous ◽  
Luis Gonzalez ◽  
Benjamin E. Botsford ◽  
Tamara L. Lenis ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Clinical Utility ◽  
Clinical Decision Making ◽  
Imaging System ◽  
Imaging Modality ◽  
Case Series ◽  
Subretinal Fluid ◽  
Optical Coherence ◽  
Swept Source ◽  
Oct Imaging

Purpose: This work aims to evaluate the clinical utility and feasibility of a novel scanning laser ophthalmoscope-based navigated ultra-widefield swept-source optical coherence tomography (UWF SS-OCT) imaging system. Methods: A retrospective, single-center, consecutive case series evaluated patients between September 2019 and October 2020 with UWF SS-OCT (modified Optos P200TxE, Optos PLC) as part of routine retinal care. The logistics of image acquisition, interpretability of images captured, nature of the peripheral abnormality, and clinical utility in management decisions were recorded. Results: Eighty-two eyes from 72 patients were included. Patients were aged 59.4 ± 17.1 years (range, 8-87 years). During imaging, 4.4 series of images were obtained in 4.1 minutes, with 86.4% of the image series deemed to be diagnostic of the peripheral pathology on blinded image review. The most common pathologic findings were chorioretinal scars (18 eyes). In 31 (38%) eyes, these images were meaningful in supporting clinical decision-making with definitive findings. Diagnoses imaged included retinal detachment combined with retinoschisis, retinal hole with overlying vitreous traction and subretinal fluid, vitreous inflammation overlying a peripheral scar, Coats disease, and peripheral retinal traction in sickle cell retinopathy. Conclusions: Navigated UWF SS-OCT imaging was clinically practical and provided high-quality characterization of peripheral retinal lesions for all eyes. Images directly contributed to management plans, including laser, injection or surgical treatment, for a clinically meaningful set of patients (38%). Future studies are needed to further assess the value of this imaging modality and its role in diagnosing, monitoring, and treating peripheral lesions.

scholarly journals Slit Wall Effect on the Stability of Wavy Vortex Flow

2014 ◽  
Vol 6 ◽  
pp. 853069 ◽  
Author(s):  
Dong Liu ◽  
Ying-ze Wang ◽  
Hyoung-Bum Kim ◽  
Fang-neng Zhu ◽  
Chun-lin Wang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Radial Velocity ◽  
Flow Regime ◽  
Experimental Measurement ◽  
Vortex Flow ◽  
Wall Effect ◽  
Taylor Vortices ◽  
Simulation Results ◽  
The Stability

The wavy vortex flow in the plain model was studied by experimental measurement; the preliminary feature of wavy vortex flow was obtained. This flow field in the plain model was also studied by numerical simulation. The reliability of numerical simulation was verified by comparing with the experimental and numerical simulation results. To study the slit wall effect on the wavy vortex flow regime, another two models with different slit number were considered; the slit number was 6 and 12. By comparing the wavy vortex flow field in different models, the axial fluctuation of Taylor vortices was found to be different, which was increased with the increasing of slit number. The maximum radial velocity from the inner cylinder to the outer one in the 6-slit number was increased by 12.7% compared to that of plain model. From the results of different circumferential position in the same slit model, it can be found that the maximum radial velocity in slit plane is significantly greater than that in other planes. The size of Taylor vortices in different models was also calculated, which was found to be increased in the 6-slit model but was not changed as the slit number increased further.

scholarly journals Swept-Source Optical Coherence Tomography Detecting Intraoperative Acute Descemet's Fold Formation

2016 ◽  
Vol 7 (2) ◽  
pp. 354-358
Author(s):  
Yu Ichioka ◽  
Akihito Uji ◽  
Nagahisa Yoshimura
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Coherence ◽  
Swept Source ◽  
En Face Oct ◽  
En Face ◽  
Descemet's Membrane ◽  
Descemet’S Membrane ◽  
Oct Imaging ◽  
Fold Formation ◽  
B Scan Images

Background: To present an intraoperative acute Descemet’s fold formation using swept-source optical coherence tomography (SS-OCT) imaging. Case Report: A 67-year-old man complaining of reduced visual acuity in the left eye. A 25-gauge pars plana vitrectomy combined with phacoemulsification cataract surgery was performed to remove the vitreomacular traction. When hydro-sealing was performed, striae rapidly spread in the cornea. SS-OCT B-scan images performed on postoperative day 1 revealed a wavy Descemet’s membrane that might correspond to Descemet’s folds. Pairs of hypo- and hyperreflective narrow lesions running from the wavy Descemet’s membrane to almost half of the thickness of the whole cornea were observed. En face OCT imaging clearly showed the stromal fold, which continuously spread from the Descemet’s fold. Conclusion: The stromal fold might be due to the focal bulge of the stroma posteriorly caused by the rapid volume increase of the stroma which could push Descemet’s membrane posteriorly, thereby forming a wavy Descemet’s membrane layer.

scholarly journals Hopf Bifurcation and Chaos of a Delayed Finance System

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Xuebing Zhang ◽  
Honglan Zhu
Keyword(s):  
Numerical Simulation ◽  
Hopf Bifurcation ◽  
Center Manifold ◽  
Chaotic State ◽  
Bifurcation And Chaos ◽  
Finance System ◽  
Center Manifold Theorem ◽  
Normal Form Method ◽  
Simulation Results ◽  
The Stability

In this paper, a finance system with delay is considered. By analyzing the corresponding characteristic equations, the local stability of equilibrium is established. The existence of Hopf bifurcations at the equilibrium is also discussed. Furthermore, formulas for determining the direction of Hopf bifurcation and the stability of the bifurcating periodic solutions are derived by applying the normal form method and center manifold theorem. Finally, numerical simulation results are presented to validate the theoretical analysis. Numerical simulation results show that delay can lead a stable system into a chaotic state.

Dual core ytterbium doped fiber ring laser in Fourier domain mode locked operation for swept-source optical coherence tomography

2010 ◽  
Author(s):  
Mark K. Harduar ◽  
Adrian Mariampillai ◽  
Barry Vuong ◽  
Kyle H. Y. Cheng ◽  
Lawrence R. Chen ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Ring Laser ◽  
Fourier Domain ◽  
Optical Coherence ◽  
Fiber Ring Laser ◽  
Fiber Ring ◽  
Swept Source ◽  
Dual Core

scholarly journals Theoretical Analytical Solution of Deformation and Stress Distribution of Underground Gas Storage Cavern in Bedded Salt Rock

2018 ◽  
Vol 64 (4) ◽  
pp. 37-53
Author(s):  
P. Xie ◽  
H.J. Wen ◽  
G.J. Wang ◽  
J. Hu
Keyword(s):  
Numerical Simulation ◽  
General Solution ◽  
Gas Storage ◽  
Displacement Function ◽  
Inverse Laplace Transform ◽  
Salt Rock ◽  
Underground Gas Storage ◽  
Simulation Results ◽  
Stress And Deformation ◽  
The Stability

Abstract The main purpose of the study is to investigate the mechanical properties around an underground gas storage cavern in bedded salt rock. Firstly, considering the characteristics of the salt rock formation in China, the mechanical model was simplified into a hollow cylinder, which containing non-salt interlayer. In terms of elastic theory, Love displacement function was developed, and the elastic general solution of stress and deformation components were obtained after determining the undetermined coefficients. Under the same condition, numerical simulation was carried out. The validity of the elastic general solution is verified by comparing to numerical simulation results. Furthermore, Based on the feasible general elastic solution, viscoelastic solution was obtained through Laplace transformation and inverse Laplace transform, which could provide reference for the study on the stability and tightness of underground gas storage carven during operation to some extent.

scholarly journals Experimental and simulated milling stability tests

Mechanik ◽  
2017 ◽  
Vol 90 (11) ◽  
pp. 965-967
Author(s):  
Piotr Andrzej Bąk ◽  
Krzysztof Jemielniak
Keyword(s):  
Numerical Simulation ◽  
Stability Analysis ◽  
Time Domain ◽  
Cutting Parameters ◽  
Milling Machine ◽  
Machined Surface ◽  
Simulation Results ◽  
The Stability ◽  
The Time Domain

Self-excited vibrations significantly reduce the milling productivity, deteriorate the quality of machined surface and tool life. One of the ways to avoid these vibrations is to modify the cutting parameters based on the stability analysis results. A method of numerical simulation of self-excited vibrations in the time domain can be used for this purpose. A comparison of numerical simulation results with those from experiments conducted using a milling machine is presented. The results confirm the correctness of applied modeling.

Fuzzy Parameter Based Mathematical Model on Forest Biomass

2018 ◽  
Vol 13 (04) ◽  
pp. 179-193 ◽  
Author(s):  
Prabir Panja
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Time Delay ◽  
Human Population ◽  
Equilibrium Points ◽  
Forest Biomass ◽  
Simulation Results ◽  
The Stability ◽  
Fuzzy Parameter

In this paper, a fuzzy mathematical model has been developed by considering forest biomass, human population and technological effort for the conservation of forest biomass as separate compartments. We have assumed that the forest biomass and human population grows logistically. We have considered that forest biomass decreases due to industrialization, food, shelter, etc., for humans. For the conservation of forest biomass, some modern technological efforts have been used in this model. Also, time delay of use of modern technological effort for the conservation of forest biomass has been considered on forest biomass. According to the assumptions, a fuzzy mathematical model on forest biomass is formulated. Next we have determined different possible equilibrium points. Also, the stability of our proposed system around these equilibrium points has been discussed. Finally, some numerical simulation results have been presented for better understanding of our proposed mathematical model.

scholarly journals WAVELENGTH PROBING OPTICAL COHERENCE TOMOGRAPHY

2011 ◽  
Vol 04 (01) ◽  
pp. 79-88
Author(s):  
SHOUDE CHANG ◽  
YOUXIN MAO
Keyword(s):  
Optical Coherence Tomography ◽  
Fourier Series ◽  
Internal Structure ◽  
Narrow Band ◽  
Spectral Feature ◽  
Time Sequence ◽  
Optical Coherence ◽  
Swept Source ◽  
Testing Sample ◽  
Oct Imaging

In swept-source optical coherence tomography (SSOCT), the swept-source stimulates system by a series of wavelengths in time sequence; a photo detector then collects all reflected/backscattered light from testing sample as the components of Fourier series. Due to the nature of the SSOCT, the processing in spectral domain can merge multiple swept-sources with different central wavelengths, which greatly increases the resolution of the OCT imaging. In the wavelength probing OCT, a standard broadband SSOCT system is used to extract the internal structure of the sample, and another narrow band light can be used to probe the spectral feature of the sample at the probing wavelength.

scholarly journals Stability of Intraocular Lens With Different Haptic Design: A Swept-Source Optical Coherence Tomography Study

2021 ◽  
Vol 8 ◽  
Author(s):  
Zixuan Xiao ◽  
Geng Wang ◽  
Miaoru Zhen ◽  
Zifeng Zhao
Keyword(s):  
Optical Coherence Tomography ◽  
Intraocular Lens ◽  
Anterior Segment ◽  
Loop Group ◽  
Optical Coherence ◽  
Swept Source ◽  
Loop Design ◽  
Plate Group ◽  
The Stability

Purpose: To investigate the stability of intraocular lens (IOLs) with different haptics by swept-source anterior-segment optical coherence tomography (AS-OCT).Methods: Sixty-eight eyes from 55 patients received the implantation of Rayner 920H (Closed C-loop Group), Zeiss 509M (Plate Group) or Lenstec SOFTEC HD (C-loop Group) IOLs. The tilt and decentration of IOLs were evaluated using AS-OCT at least 1 month postoperatively.Results: Mean decentration and tilt of IOLs were 0.18 ± 0.12 mm (range 0.02 to 0.59 mm) and 5.63 ± 1.65° (range 2.2 to 9.6°) respectively. Decentration was significantly smaller in the plate haptic group (0.12 ± 0.06 mm) as compared to the C-loop group (0.22 ± 0.13 mm, P = 0.02). The tilt of IOL was also significantly smaller in the plate haptic group (4.96 ± 0.89°) as compared to the C-loop group (6.28 ± 1.83°, P = 0.01). There was marginal difference between the Closed C-loop group (5.52 ± 1.74°) and C-loop group (6.28 ± 1.83°, P = 0.07).Conclusions: The Plate-haptic IOLs should have better stability for the decentration and tilt than the C-loop design IOLs.

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