- 标题
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- 实验方案
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Application of Capillary Zone Electrophoresis Coupled with a Diode Array Detector (CZE-DAD) for Simultaneous Analysis of Ibuprofen and Phenylephrine
摘要： Background: A validated method based on capillary zone electrophoresis coupled with a diode array detector (CZE-DAD) was investigated for analyzing binary mixture of ibuprofen (IBU) and phenylephrine (PHE) in their bulk and combined dosage form. Objective: This binary mixture is a challenging one as IBU is acidic and PHE is alkaline, which may affect their simultaneous analysis using CZE. The literature lacks any CZE report for IBU and PHE simultaneous analysis. Methods: Fused silica capillary (85 cm × 75 μm id) was used, and the electrolyte was a 50 mM borate buffer adjusted to pH 11 with 0.5 M NaOH. Results: The concentration ranges were 5–200 and 5–100 μg/mL for IBU and PHE, respectively, using CZE. High efficiency was achieved (N > 92990). Reasonable migration time (tm) was attained (tm< 8.5 min). Conclusions: Although the results obtained by the proposed CZE method and reported HPLC method were statistically comparable, the proposed method showed lower linearity ranges, higher efficiency, and a more reasonable run time. Highlights: CZE-DAD was used for the analysis of IBU and PHE in bulk and tablets, as no report was found for their determination using CZE. Binary mixture is challenging due to differences in chemical and physical properties. A detailed discussion of electrophoretic parameters optimization is included. Confirmation of peak purity was attained using DAD.
关键词： Capillary zone electrophoresis,phenylephrine,diode array detector,simultaneous analysis,ibuprofen
更新于2025-09-23 15:21:01
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[IEEE 2020 International Conference on COMmunication Systems & NETworkS (COMSNETS) - Bengaluru, India (2020.1.7-2020.1.11)] 2020 International Conference on COMmunication Systems & NETworkS (COMSNETS) - Demonstration of High Data-rate Multimedia Streaming in a Laser-based Indoor Visible Light Communication System
摘要： We report the demonstration of real-time high-quality multimedia data streaming over a laser-based indoor visible light communication (VLC) link consisting of blue laser diode excited remote phosphor as transmitter, an amplified ac-coupled silicon photodetector as the receiver and USRP platforms for data modulation/ demodulation. The VLC link has been separately characterized and supports bandwidth > 800 MHz. Streaming of 1280 x 720 HD video is successfully demonstrated over this VLC link with an ethernet link data rate of 200Mbps and RF carrier frequency at the radio front-end at 245 MHz. When compared to previous multimedia streaming demonstrations in LED based VLC links, the high link data rates, and RF carrier frequency as reported here are achievable due to the large inherent bandwidth supported by laser sources. The potential applications of this demonstration are in next-generation heterogeneous wireless networks in which Wi-Fi and VLC links link as co-exist. The high-bandwidth optical wireless link demonstrated here is suitable for low-latency, data-intensive, dedicated communication, for example in robotic telepresence, tactile tasks, etc.
关键词： Multimedia Streaming,Laser Diode,Visible Light Communication,USRP
更新于2025-09-23 15:21:01
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Temperature Dependence Model of the Laser Diode Bar Current-Voltage Characteristic
摘要： Based on an analysis of di?erences between the experimentally measured temperature dependence of the current-voltage characteristic (I–V curve) of a laser diode bar (LDB) with AlGaAs/GaAs heterostructure and the dependence obtained in accordance with the well-known model of light-emitting diodes, assumptions were made about the sources of these di?erences. The agreement between the experimental and modeled dependences is signi?cantly improved by taking into consideration the change in the resistance of LDB layers caused by temperature change. It is shown that when the injection current is known, the measured voltage drop across the LDB can be used to estimate the temperature of the diode active region in order to implement thermal stabilization for solid-state laser pumping systems based on high-power laser diodes.
关键词： temperature,electrical potential di?erence,laser diode bar,current-voltage characteristic
更新于2025-09-23 15:21:01
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Conditioned media from blue light-emitting diodea??exposed fibroblasts have an anti-inflammatory effect in vitro
摘要： We have previously reported the protective effects of blue light-emitting diode (BLED)–stimulated cell metabolites on cell injury. To further examine the effect of conditioned media (CM) derived from BLED (5 J/cm2)-exposed human normal fibroblasts (CMBL5) for clinical application, we have used the choline chloride and phenol red–free media and then concentrated CMBL5 using a centrifugal filter unit. The collected CMBL5-lower part (CMBL5-LO) has evaluated the inflammatory protein expression profile in LPS-stimulated RAW264.7 cells. Comprehensive metabolomic profiling of CMBL5-LO was carried out using hybrid tandem mass spectrometry. Treatment with CMBL5-LO showed the cytoprotective effect on apoptotic cell death, but rather increased apoptotic cells after treatment with CMBL5-upper part (CMBL5-UP). In addition, CMBL5-LO inhibited several chemo-attractants, including interleukin (IL)-6, macrophage inflammatory protein (MIP)-2, chemokine (C-C motif) ligand 5 (CCL5), granulocyte colony-stimulating factor (GCSF), and monocyte chemoattractant protein-1 (MCP-1) expression. Pro-inflammatory nitric oxide was decreased after CMBL5-LO treatment, but not by CMBL5-UP treatment. Interestingly, treatment with CMBL5-LO stimulated expression of heme oxygenase-1, indicating its anti-inflammatory property. Most endoplasmic reticulum (ER) stress proteins except for transcription factor C/EBP homologous protein (CHOP) were highly expressed after irradiation with BLED in cells. Further studies are needed to examine the precise mechanism by CMBL5-LO in cells.
关键词： Inflammation,CMBL5-LO,Light-emitting diode,ER stress
更新于2025-09-23 15:21:01
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CsPbBr3 nanowire polarized light-emitting diodes through mechanical rubbing
摘要： Anisotropic films composed of aligned CsPbBr3 nanowires (NWs) have been successfully fabricated using a mechanical rubbing method. The films with dense and uniform morphology show polarization photoluminescence (PL) behavior. Combining with an optimal device structure, a polarized light-emitting diode (LED) with a turn-on voltage as low as 6.5 V was achieved.
关键词： CsPbBr3 nanowires,anisotropic films,mechanical rubbing,polarized light-emitting diode,photoluminescence
更新于2025-09-23 15:21:01
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The Chicago Water Isotope Spectrometer (ChiWIS-lab): A tunable diode laser spectrometer for chamber-based measurements of water vapor isotopic evolution during cirrus formation
摘要： We describe a new tunable diode laser (TDL) absorption instrument, the Chicago Water Isotope Spectrometer, designed for measurements of vapor-phase water isotopologues in conditions characteristic of the upper troposphere [190–235 K temperature and 2–500 parts per million volume (ppmv) water vapor]. The instrument is primarily targeted for measuring the evolving ratio of HDO/H2O during experiments in the “Aerosol Interaction and Dynamics in the Atmosphere” (AIDA) cloud chamber. The spectrometer scans absorption lines of both H2O and HDO near the 2.64 μm wavelength in a single current sweep, increasing the accuracy of isotopic ratio measurements. At AIDA, the instrument is configured with a 256-m path length White cell for in situ measurements, and effective sensitivity can be augmented by enhancing the HDO content of chamber water vapor by an order of magnitude. The instrument has participated to date in the 2012–2013 IsoCloud campaigns studying isotopic partitioning during the formation of cirrus clouds and in the AquaVIT-II instrument intercomparison campaign. Realized precisions for 1-s measurements during these campaigns were 22 ppbv for H2O and 16 ppbv for HDO, equivalent to relative precisions of less than 0.5% for each species at 8 ppmv water vapor. The 1-s precision of the [HDO]/[H2O] ratio measurement ranged from 1.6‰ to 5.6‰ over the range of experimental conditions. H2O measurements showed agreement with calculated saturation vapor pressure to within 1% in conditions of sublimating ice and agreement with other AIDA instruments (the AIDA SP-APicT reference TDL instrument and an MBW 373LX chilled mirror hygrometer) to within 2.5% and 3.8%, respectively, over conditions suitable for all instruments (temperatures from 204 K to 234 K and H2O content equivalent to 15–700 ppmv at 200 hPa).
关键词： upper troposphere,isotopic ratio measurements,water isotopologues,AIDA cloud chamber,tunable diode laser
更新于2025-09-23 15:21:01
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A simple extended-cavity diode laser using a precision mirror mount
摘要： We have developed an extended-cavity diode laser (ECDL) with a simple design by using a commercial precision mirror mount with minor modifications. Our design allows tuning of the external cavity configuration by tweaking the volume holographic grating without troublesome changes in the beam path of the laser output. The mode-hop-free tuning range of the presented ECDL is about 8 GHz with a linewidth of 475 kHz.
关键词： volume holographic grating,mode-hop-free tuning range,linewidth,extended-cavity diode laser,precision mirror mount
更新于2025-09-23 15:21:01
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Reconfigurable 2D/0D pa??n Graphene/HgTe Nanocrystal Heterostructure for Infrared Detection
摘要： Nanocrystals are promising building blocks for the development of low-cost infrared optoelectronics. Gating a nanocrystal film in a phototransistor geometry is commonly proposed as a strategy to tune the signal-to-noise ratio by carefully controlling the carrier density within the semiconductor. However, the performance improvement has so far been quite marginal. With metallic electrodes, the gate dependence of the photocurrent follows the gate-induced change of the dark current. Graphene presents key advantages: (i) infrared transparency that allows back-side illumination, (ii) vertical electric field transparency, and (iii) carrier selectivity under gate bias. Here, we investigate a configuration of 2D/0D infrared photodetectors taking advantage of a high capacitance ionic glass gate, large-scale graphene electrodes, and a HgTe nanocrystals layer of high carrier mobility. The introduction of graphene electrodes combined with ionic glass enables one to reconfigure selectively the HgTe nanocrystals and the graphene electrodes between electron-doped (n) and hole-doped (p) states. We unveil that this functionality enables the design a 2D/0D p?n junction that expands throughout the device, with a built-in electric field that assists charge dissociation. We demonstrate that, in this specific configuration, the signal-to-noise ratio for infrared photodetection can be enhanced by 2 orders of magnitude, and that photovoltaic operation can be achieved. The detectivity now reaches 109 Jones, whereas the device only absorbs 8% of the incident light. Additionally, the time response of the device is fast (<10 μs), which strongly contrasts with the slow response commonly observed for 2D/0D mixed-dimensional heterostructures, where larger photoconduction gains come at the cost of slower response.
关键词： gate-induced diode,infrared detection,narrow band gap nanocrystals,HgTe,graphene
更新于2025-09-23 15:21:01
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Development and Study of the pa??ia??n GaAs/AlGaAs Tunnel Diodes for Multijunction Converters of High-Power Laser Radiation
摘要： The creation of connecting tunnel diodes with a peak tunneling-current density higher than the density of the short-circuit current of photoactive p–n junctions is an important task in the development of multijunction photoconverters (III–V) of high-power optical radiation. Basing on numerical simulation of the J–U characteristics of tunnel diodes, a method is proposed for increasing the peak tunneling-current density by including a thin undoped i-type layer with a thickness of several nanometers between degenerate layers of the tunnel diode. The p–i–n-GaAs/Al0.2Ga0.8As structures of the connecting tunnel diodes with a peak tunneling-current density of up to 200 A/cm2 are grown by molecular-beam epitaxy.
关键词： quantum tunneling,molecular-beam epitaxy,tunnel diode,multijunction photoconverter,current–voltage characteristic
更新于2025-09-23 15:21:01
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High Speed Directly Modulated Fabry-Perot Lasers with an Ultra-Short Cavity Length
摘要： In this study, Fabry-Perot quantum well lasers with shortened cavity designs (25 and 50 μm) were fabricated. The devices had dry-etched and cleaved facets that exhibited an output power of up to 2.36 mW for a cavity length of 25 μm; good spectral performance was achieved. Single-optical-mode operation with better than 25dB of side mode suppression ratio can be achieved for the fabricated devices with 25- and 50-μm cavities. The short-cavity devices also exhibited high-speed modulation at elevated temperatures. Moreover, 25 Gb/s eye diagrams could be obtained at 65oC for the 25 μm device and 55oC for the 50 μm device. Due to their small area, ultra-short-cavity Fabry-Perot laser can be suitably used in next-generation light sources for optical communication.
关键词： Optical device fabrication,Semiconductor lasers,Laser cavity resonators,Amplitude modulation,Diode lasers,Quantum well lasers,Laser modes
更新于2025-09-23 15:21:01