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[IEEE 2017 IEEE Workshop on Recent Advances in Photonics (WRAP) - Hyderabad (2017.12.18-2017.12.19)] 2017 IEEE Workshop on Recent Advances in Photonics (WRAP) - Differential Pressure Sensor Using Integrated Optical MEMS and Double Ring Resonator
摘要： In this work, we designed and simulated a differential pressure sensor using a double ring resonator with radius 5μm and 4μm placed on the fixed of a cantilever beam with dimensions 100μm x 30μm x 5μm. The stress induced on the cantilever changes the refractive index in the waveguide which results in the shift of the resonant wavelength. A sensitivity of 15.544pm/kPa is achieved. The sensor is operated at wavelength equal to 1.55μm and can be used for aircraft, medicine and automobile.
关键词： Cantilever beam,Opto-mechanical effect,Differential pressure sensor,Double ring resonator
更新于2025-09-23 15:22:29
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[IEEE 2018 14th IEEE International Conference on Solid-State and Integrated Circuit Technology (ICSICT) - Qingdao, China (2018.10.31-2018.11.3)] 2018 14th IEEE International Conference on Solid-State and Integrated Circuit Technology (ICSICT) - Design of a flexible MEMS pressure sensor array in dog’s artificial knee joint
摘要： This paper proposed a novel design of flexible sensor array which can be applied to measure the pressure distribution in the dog’s artificial knee joint after the Total Knee Arthroplasty(TKA). Using MEMS technology, the flexible sensor array mainly consists of 100 sensing points which are fabricated based on SOI, and spin-coated polyimide(PI) films. It is strongly attached to the surface of polyethylene insert in the dog’s artificial knee joint. The flexible MEMS sensor array is biocompatible for vivo animal experiment and expected to play an important role in the research of improving the surgery effect of TKA.
关键词： flexible pressure sensor,MEMS,artificial knee joint
更新于2025-09-23 15:22:29
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Donor Impurity States in Semiconductor Zincblende Nitride Quantum Systems as a Source of Nonlinear Optical Response
摘要： The optical absorption and the optical rectification coefficients associated to hydrogenic impurity interstate transitions in zincblende GaN-based nanostructures of the quantum wire type are investigated. The system is assumed to have cylindrical shape and the influence of external tuning probes such as hydrostatic pressure and static electric fields is particularly taken into account. The electron states are obtained within the effective mass approximation, via the exact diagonalization of the donor-impurity Hamiltonian with parabolic confinement. The nonlinear optical coefficients are calculated using a nonperturbative solution of the density-matrix Bloch equation. Our results show that the resonance-related features of the optical response become shifted in the frequency range of the incident radiation due to the effect of the hydrostatic pressure, the strength of the applied field and the change in the impurity center position.
关键词： Quantum Wire,Nonlinear Optics,Hydrostatic Pressure,Zincblende GaN
更新于2025-09-23 15:22:29
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Comparative Study of Optical Coherence Tomography Angiography and Phase-Resolved Doppler Optical Coherence Tomography for Measurement of Retinal Blood Vessels Caliber
摘要： Purpose: To compare the accuracy of Doppler optical coherence tomography (DOCT) and OCT angiography (OCTA) for measuring retinal blood vessel caliber at different flow rates. Methods: A research-grade 1060-nm OCT system with 3.5-lm axial resolution in retinal tissue and 92,000 A scan/s image acquisition rate was used in this study. DOCT and OCTA measurements were acquired both from a flow phantom and in vivo from retinal blood vessels in six male Brown Norway rats. The total retinal blood flow (TRBF) was modified from baseline to 70% and 20% of baseline by reducing the ocular perfusion pressure (OPP). The retinal blood vessel caliber (RBVC) was measured from OCTA and DOCT images. The caliber measurements were conducted by two separate graders using a custom MATLAB-based image processing algorithm. Results: The RBVC measured with OCTA and DOCT for normal blood flow rates were not significantly different (56.69 6 12.17 and 57.17 6 9.46 lm, P ? 0.27, respectively). However, significant differences were detected when TRBF was reduced to 70% (55.69 6 11.56 vs. 50.62 6 8.85 lm, P , 0.01) and 20% (50.29 6 9.29 vs. 44.88 6 7.13 lm, P , 0.01) of baseline. Conclusions: Reduced TRBF resulted in inaccuracy of the RBVC measurements with DOCT in both the phantom and animal study. This result suggests that OCTA is a more accurate tool for RBVC evaluation when applied to retinal diseases associated with reduced TRBF, such as glaucoma and diabetic retinopathy. Translational Relevance: Results from this study are directly applicable to clinical studies of retinal blood flow measured with OCTA and DOCT.
关键词： optical coherence tomography angiography,ocular perfusion pressure,retinal imaging,doppler optical coherence tomography
更新于2025-09-23 15:22:29
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Flap double twist technique for prevention of LASIK flap striae
摘要： A novel flap double twist technique was applied to reduce the incidence of post-laser-assisted in situ keratomileusis (LASIK) flap striae. The flap is floated and stroked in the same way as is done for management of first postoperative day striae, where the method is to float and irrigate the flap into position, followed by applying gentle pressure on the flap with a wet Merocel microsponge and moving the flap away from the hinge position. The sponge is then manually squeezed to become drier, and the flap is continuously stroked in a direction opposite to the hinge. Next, the flap is carefully twisted obliquely and sequentially in two opposite directions while applying gentle pressure on the flap in order to completely dehydrate the flap and stromal bed. Finally, the flap is repositioned while applying gentle horizontal pressure in two opposite directions. This novel flap double twist technique shows great success in post-LASIK striae prevention.
关键词： laser-assisted in situ keratomileusis,microsponge,pressure,wrinkles
更新于2025-09-23 15:22:29
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A Comparative Study of Pressure Cooker, Ultra-Violet and RO Methods of Water Purification
摘要： In this work, the performances of the pressure cooker method, the ultra-violet method and RO method of water purification is studied. The performance of any method studied here relates to the production of potable water which meets the World Health Organization (WHO) standards. This comparative study is based on underground water obtained from a depth greater than 300 feet. The results showed that all these three methods yield same level of purity.
关键词： potable water,pressure cooker method,Water purification,reverse osmosis method,ultra-violet method
更新于2025-09-23 15:22:29
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Hypertension Assessment Using Photoplethysmography: A Risk Stratification Approach
摘要： Hypertension is a common chronic cardiovascular disease (CVD). Early screening and diagnosis of hypertension plays a major role in its prevention and in the control of CVDs. Our study discusses the early screening of hypertension while using the morphological features of photoplethysmography (PPG). Numerous morphological features of PPG and its derivative waves were defined and extracted. Six types of feature selection methods were chosen to screen and evaluate these PPG morphological features. The optimal features were comprehensively analyzed in relation to the physiological processes of the cardiovascular circulatory system. Particularly, the intrinsic relation and physiological significance between the formation process of systolic blood pressure (SBP) and PPG morphology features were analyzed in depth. A variety of linear and nonlinear classification models were established for the comparison trials. The F1 scores for the normotension versus prehypertension, normotension and prehypertension versus hypertension, and normotension versus hypertension trials were 72.97%, 81.82%, and 92.31%, respectively. In summary, this study established a PPG characteristic analysis model and established the intrinsic relationship between SBP and PPG characteristics. Finally, the risk stratification of hypertension at different stages was examined and compared based on the optimal feature subset.
关键词： Hypertension,photoplethysmograph,feature selection,systolic blood pressure,risk classification
更新于2025-09-23 15:22:29
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Red-Free Light for Measurement of Intraocular Pressure Using Goldmann Applanation Tonometer without Fluorescein
摘要： Purpose: To evaluate the use of red-free light for the measurement of intraocular pressure (IOP) using a Goldmann applanation tonometer without fluorescein. Methods: This cross-sectional study was carried out on 500 eyes in 250 patients attending the Ophthalmology Outpatient Clinic at Suez Canal University Hospital. The IOP was measured using a Goldmann applanation tonometer mounted on a Haag-Streit slit-lamp. The measurements were performed first using red-free light without fluorescein. Then the measurements were repeated with cobalt blue light and topical fluorescein on the same eyes. Results: The mean IOP was 15.23 ± 3.3 (SD) mm Hg using the red-free light without fluorescein, whereas it was 15.78 ± 3.7 (SD) mm Hg when measured using cobalt blue light after the application of fluorescein to the conjunctival sac. This difference was not statistically significant. Conclusions: Measurement of IOP with a Goldmann applanation tonometer with red-free light and without the use of fluorescein is simple, saves time, and gives an accurate IOP measurement relative to the traditional measurement technique with cobalt blue light and topical fluorescein.
关键词： Red-free light,Intraocular pressure,Goldmann applanation tonometer
更新于2025-09-23 15:22:29
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Dynamic changes in optic disc morphology, choroidal thickness, anterior chamber parameters, and intraocular pressure during Valsalva maneuver
摘要： Purpose: To investigate the effects of the Valsalva maneuver (VM) on optic disc morphology, choroidal thickness, and anterior chamber parameters. Methods: This prospective observational study included 60 eyes of 60 healthy subjects. The anterior chamber parameters, including central corneal thickness (CCT), anterior chamber depth (ACD), anterior chamber angle (ACA), anterior chamber volume (ACV), pupil diameter (PD), axial length (AL), subfoveal and peripapillary choroidal thickness, optic disc parameters, and intraocular pressure (IOP), were measured at rest and during VM. Results: VM did not have any significant influence on AL, subfoveal and peripapillary choroidal thickness, optic disc area, rim area, cup area, cup-to-disc area ratio, vertical cup-to-disc ratio, rim volume, cup volume, and nerve head volume measurements (for all; p>0.05). IOP and PD significantly increased during VM (for both; p<0.001). VM significantly decreased CCT, ACD, ACA, and ACV values (for all; p<0.001). Moreover, the optic nerve cup volume decreased and the horizontal cup-to-disc ratio significantly increased during VM (for both; p<0.05). Conclusions: VM may cause transient changes in IOP, optic disc morphology, and anterior chamber parameters.
关键词： Anterior chamber,Optic disc/anatomy & histology,Valsalva maneuver,Intraocular pressure,Choroid/anatomy & histology
更新于2025-09-23 15:22:29
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Pressure-induced phase transitions, electronic, elastic and vibrational properties of zinc oxide under high pressure
摘要： In this work, the crystal structure of the ZnO was studied under high hydrostatic pressure using ab initio calculations. Pressure–volume relationships and structural transitions in ZnO were investigated using Siesta method. A first-order transition from the hexagonal wurtzite (B4) structure with space group P63mc to the cubic NaCl (B1) structure with space group Fm(cid:2)3m was successfully observed. A transition was also observed from Fm(cid:2)3m to another cubic CsCl (B2) structure with space group Pm(cid:2)3m for ZnO. These phase transitions which occur around 9 and 119.5 GPa were also analyzed from the total energy and enthalpy calculations. In addition, electronic, elastic and vibrational properties of ZnO were analyzed based on the high pressure.
关键词： Bulk crystals,Electronic structure calculations,Pressure,Phase transitions
更新于2025-09-23 15:22:29