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[IEEE 2019 SBFoton International Optics and Photonics Conference (SBFoton IOPC) - Sao Paulo, Brazil (2019.10.7-2019.10.9)] 2019 SBFoton International Optics and Photonics Conference (SBFoton IOPC) - High-Performance and Small Form-Factor Tunable Lasers for High-Capacity Telecom Systems
摘要： In this work, an overview of requirements for compact optical modules and devices is presented, focusing on optical laser sources. Regarding coherent applications, the laser must have narrow linewidth, while, at the same time, be compact and present low power consumption, targeting C-form factor pluggable (CFP) modules. Latest results obtained by our group on laser development are presented, showing that the External-Cavity Laser (ECL) can fulfill the requirements for this application.
关键词： C-form factor modules,coherent optical communication,external cavity laser,micro-ITLA,narrow-linewidth laser
更新于2025-09-16 10:30:52
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Microfluidic synthesis of PLGA/carbon quantum dot microspheres for vascular endothelial growth factor delivery
摘要： In this study, vascular endothelial growth factor (VEGF) loaded poly(D,L-lactide-co-glycolide) (PLGA) – carbon quantum dot microspheres were produced using micro?uidic platforms. The microcapsules were fabricated in ?ow-focusing geometry with a biphasic ?ow to generate solid/oil/water (s–o–w) droplets. To avoid any damage to protein functional and structural stability during the encapsulation process, the VEGF was PEGylated. The produced microspheres were intact and highly monodisperse in size (CV < 5%). Furthermore, microspheres in a size range of 16–36 mm were achieved by adjusting the ?ow ratio parameter. The encapsulation e?ciency, release pro?le, and bioactivity of the produced microparticles were also studied. The loading e?ciency of PEGylated VEGF in the microparticles was varied from 51–69% and more than 90% of PEGylated VEGF was released within 28 days. Furthermore, the release of VEGF was indirectly monitored by carbon quantum dots. The present monodisperse and controllable VEGF loaded microspheres with reproducible manner could be widely used in tissue engineering and therapeutic applications.
关键词： PLGA,vascular endothelial growth factor,carbon quantum dot,drug delivery,Micro?uidic synthesis
更新于2025-09-16 10:30:52
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Scanning a Silicon Photomultiplier with a Laser Beam
摘要： The Silicon Photomultiplier (SiPM) is a novel semiconducting photodetector which can detect single photons. It consists of many microcells (pixels) operating in the so-called Geiger mode. At present, there are two principal designs among such devices: surface pixel and deeply buried pixel (microwell) structures. The cellular structure decreases the device’s effective photosensitive area, expressed in terms of the geometrical fill factor. It is very important to take it into account when developing new constructions with high pixel densities that are necessary for increasing the dynamic range. It is believed that the fill factor of deep microwell SiPMs is close to unity. In this work, the technique and results of studying the zonal response of different SiPMs by scanning (moving) with micron laser spot are presented. It is shown that the geometrical fill factor of the deep microwell SiPM is less than 100% when detecting the red light (λ = 632 nm).
关键词： Silicon Photomultiplier,Geiger mode,geometrical fill factor,laser scanning,deep microwell SiPM,SiPM
更新于2025-09-16 10:30:52
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Crack closure mechanisms in residual stress fields generated by laser shock peening: A combined experimental-numerical approach
摘要： Laser shock peening (LSP) is successfully applied to retard fatigue cracks in metallic lightweight structures by introducing specific, in particular compressive, residual stress fields. In this work, experiments and a multi-step simulation strategy are used to explain the fatigue crack retarding and accelerating mechanisms within these LSP-induced residual stress fields. Crack face contact is identified as main mechanism to retard the fatigue crack as the stress distribution changes and the stress intensity factor range decreases. Crack face contact is experimentally detected by load vs. crack opening displacement (COD) curves and scanning electron microscopy (SEM) of the crack faces, as well as during numerical simulations. The convincing agreement between experiment and simulation, especially regarding the specific crack face contact areas, allowed the proper evaluation of the stress intensity factors depending on the crack length. It is found that crack closure is indeed one of the main reasons for the efficient application of LSP for fatigue crack retardation. Furthermore, the occurrence of crack closure does not indicate a zero value stress intensity factor in complex residual stress fields, as the areas of crack face contact depend strongly on the LSP-induced compressive residual stresses.
关键词： Stress intensity factor,Laser shock peening,Residual stress,Fatigue crack growth,Crack closure
更新于2025-09-16 10:30:52
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Effect of backscattering on nonlinear distortions of the scale factor of a laser gyro with a rectangular bias
摘要： We report the results of measurements of nonlinear scale factor corrections, resulting from the backscattering effect in a laser gyro with a rectangular bias. It is shown that taking conservative and dissipative backscattering components into account allows one to obtain analytical relationships that adequately describe the frequency response of a laser gyroscope over the entire working range of angular velocities. Using these relationships to correct the frequency response of a laser gyroscope makes it possible to reduce the value of nonlinear corrections to 1 – 2 ppm.
关键词： backscattering,scale factor,ring laser,frequency bias,laser gyroscope
更新于2025-09-16 10:30:52
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Theoretical Analysis and Determination of the Correction Factor for a Waveguide Microcalorimeter
摘要： This paper proposes a new method for determining the correction factor of a newly developed waveguide primary power measurement system (i.e., microcalorimeter), based on the electromagnetic field theory analysis for waveguide thermal isolation section (TIS) in foil short measurement mode. The new method determines the contribution of the power dissipated within the TIS into the correction factor, in term of the physical dimensions of the TIS. Performance comparison and analysis show that the newly proposed method can significantly reduce the measurement uncertainty when evaluating the correction factor of waveguide microcalorimeters.
关键词： primary standards,microcalorimeter,correction factor,electromagnetic field theory
更新于2025-09-16 10:30:52
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[IEEE 2019 10th International Conference on Computing, Communication and Networking Technologies (ICCCNT) - Kanpur, India (2019.7.6-2019.7.8)] 2019 10th International Conference on Computing, Communication and Networking Technologies (ICCCNT) - An organic-inorganic solar cell with graphene as an electron transport layer: an approach to increase the carrier collection efficiency
摘要： Methyl-Ammonium lead halide based solar cell has shown a tremendous approach to fulfill the energy crisis on the earth for its high efficiency and low manufacturing cost. While there are some other materials which influence the execution of Perovskite sunlight based cell, these materials are nothing but the electron as well as hole transport materials. In this article the behavior and performances of electron transport materials are mostly focused which generally increase the proficiency of Perovskite solar cell by simultaneously increasing the open circuit voltage and short circuit current. The role of graphene as an electron transport material is mainly discussed and also compared with some other metal oxide electron transport material as well as organic-based electron transport material. As keeping graphene as an electron transport material the predicted results of Perovskite solar cell are as follows: - maximum power conversion efficiency (PCE) = 23.42%, short-circuit-current-densit=3.25A/m2,open-circuit-voltage=0.86v,fill factor=0.83au. So graphene-based electron transport material can be the entry for the improvement of Perovskite solar cell.
关键词： electron transport materials,fill factor,efficiency,open circuit voltage,graphene,Perovskite solar cell,short-circuit current density
更新于2025-09-16 10:30:52
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[IEEE 2019 10th International Conference on Computing, Communication and Networking Technologies (ICCCNT) - Kanpur, India (2019.7.6-2019.7.8)] 2019 10th International Conference on Computing, Communication and Networking Technologies (ICCCNT) - Performance Analysis of Free Space Optical Communication Systems for High-Speed Trains
摘要： Free space optics(FSO) can be used as an alternative the currently used wireless Radio communication systems to meet the increasing demands for the uninterrupted internet connection in High-Speed Trains(HSTs). FSO is less prone to interference, license-free and more secure as compared to Radio Frequency (RF) technology. The performance of the FSO system can be measured in terms of the average bit error rate(BER) and quality factor (Q-factor). In this paper, we have compared the NRZ and RZ modulation formats using a dual wavelength model at a bit rate of 10 Gbps to see which modulation format gives better Q-factor. The RZ modulation format is studied for a duty cycle of 33% and 67% and the comparison is made in terms of Q-factor. The system is also studied under different weather conditions in terms of Q-factor.
关键词： HSTs(high speed trains),Q-factor,RZ,FSO,BER,NRZ
更新于2025-09-16 10:30:52
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Investigate quality factor of single tuned passive filter to reduce harmonic of LED lamp
摘要： The use of LED energy-saving lamps is proliferating in the world and ranging from homes, offices to government buildings. The main reason for this is because LED lights have relatively small electrical power consumption. Behind the advantage of saving energy, it turns out that LED lights have a high level of harmonic. Passive filter is recommended to eliminate harmonic. The Quality factor (Q) of a filter will determine its performance. If the Q value is significant, the value of R will be smaller, and the quality of the filter will also be getting better because the energy used by the filter is lowering. It indicates that the heat losses of the filter are small. This work has tested four single tuned passive filter designs on X brand LED lamps with nominal power values of 3W, 4W, and 7W. The inductor values (L) tested were 65mH, 78mH, 91mH, and 115mH, respectively. The test results show that the total harmonic distortion (THD) of voltage on the X brand LED lights does not exceed the IEEE 519-2014 standard limit which is a maximum of 5%, because the highest harmonic voltage is 2.7%. While the highest total harmonic distortion (THD) of current in the LED lamps tested was 154%. The results of installing the first filter (L = 65mH) can reduce THD current up to 90.91%, the second filter (L = 78mH) reduces THD current up to 89.81%, the third filter (L = 91mH) reduces THD current up to 89.57%, while the fourth filter (L = 115mH) reduces THD current up to 86.86%.
关键词： quality factor,LED lamp,total harmonic distortion,passive filter,harmonic
更新于2025-09-16 10:30:52
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Reconfigurable resonator in decoupled empty SIW technology using liquid crystal material
摘要： This Letter presents a novel continuously tunable microwave resonator based on liquid crystal (LC) material. The recon?gurable device is implemented in Decoupled Empty Substrate Integrated Waveguide (DESIW) technology. DESIW technology allows both magnetic and electric DC (or low frequency) biasing of the LC. The resonator is continuously tunable in a range of 600 MHz, resulting in a measured tunability range of 8.5% around a centre frequency of 7 GHz. Moreover, the measured insertion loss of the recon?gurable device is between 4.3 and 6.8 dB, thus obtaining a Q-factor of 190-172.
关键词： Q-factor,tunable,liquid crystal,microwave resonator,DESIW technology
更新于2025-09-16 10:30:52