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Comparison between Ferromagnetic and Ferroelectric Optical Switch Devices in Terms of the Response to the Electric Field
摘要： In this work we have studied the electro-optical effect of two types of ferronematic nanoparticles. The first sample doped with magnetic material Fe3O4 and the second sample doped with a ferroelectric material SbSI. The difference in the two types of material that has been vaccinated led to different values of electro-optic properties because of the different susceptibility of materials. We have noticed that the material SbSI was more responsive to the applied electric field due to the nature of the constituent material (electric material) than the Fe3O4 ferromagnetic. The response time for the material SbSI is less than the response time of the ferromagnetic Fe3O4, that led to make the material SbSI best in the optical switch applications.
关键词： Electro-Optic Properties,Response Time,Fall Time,Rise Time,Ferronematic (FN),Threshold Voltage
更新于2025-09-23 15:22:29
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A rhodamine-deoxylactam based fluorescent probe for fast and selective detection of nitric oxide in living cells
摘要： Nitric oxide (NO) plays vital roles in many physiological process and is closely related to many diseases. So far, a number of fluorescent probes have been constructed for the detection of NO successfully. However, the probes still suffer from long-time reaction and limited selectivity. Herein, a fluorescent probe named dRB-OPD is synthesized and used to recognize NO. The probe contains a deoxy-rhodamine B as fluorophore and o-phenylenediamino as reaction site. dRB-OPD shows fast response to NO within 40 seconds with 170-fold fluorescence enhancement. Moreover, the probe shows high selectivity towards NO over dehydroascorbic acid (DHA), ascorbic acid (AA), and methylglyoxal (MGO). Particularly, the probe can avoid the serious interference from cysteine (Cys) found in the rhodamine lactam-based fluorescent NO probes (RB-OPD). In addition, the probe is applied for the detection of exogenous and endogenous NO in the HepG2 and RAW 264.7 cells with satisfactory results.
关键词： Cell imaging,Fluorescent probe,Nitric oxide,High selectivity,Fast response
更新于2025-09-23 15:22:29
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Modeling and multiresponse optimization of cutting parameters in SPDT of a rigid contact lens polymer using RSM and desirability function
摘要： Amidst different conventional contact lens manufacturing techniques, single-point diamond turning (SPDT) is one of the recently developed ultra-high precision machining techniques employed in the fabrication of advanced contact lenses due to its capability of producing high optical surfaces of complex shapes and nanometric accuracy. SPDT is regarded as an effective process for the generation of high-quality functional surfaces in optical industries. However, despite advances in the ultra-high precision machining, it is not always easy to achieve a high-quality surface finish with maximum productivity. Machining parameters, namely cutting speed, feed rate, and depth of cut, play the lead role in determining the machine economics and quality of machining. The present study focuses on the determination of the optimum cutting conditions leading to minimum surface roughness as well as electrostatic charge and maximum productivity, in SPDT of the polymethyl methacrylate (PMMA) contact lens polymer using monocrystalline diamond cutting tool. The optimization is based on the response surface methodology (RSM) together with the desirability function approach. In addition, a mathematical model is developed for surface roughness (Ra), electrostatic charge (ESC), and material removal rate (MRR) using RSM regression analysis for a rigid contact lens polymer by the Design-Expert software. RSM allowed the optimization of the cutting conditions for minimal surface roughness, electrostatic charge, and maximal material removal rate which provides an effective knowledge base for process parameters, to make its enhancement of process performance in SPDT of contact lens polymer.
关键词： Electrostatic charge,Response surface methodology,Material removal rate,Surface roughness and optimization,PMMA contact lens polymer,Single-point diamond turning
更新于2025-09-23 15:22:29
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Prediction of Second-Order Nonlinear Optical Properties of D–π–A Compounds Containing Novel Fluorene Derivatives: A Promising Route to Giant Hyperpolarizabilities
摘要： Herein, ?rst attempt has been made to utilize ?uorene-based dye-sensitized solar cell (DSSCs) dye JK-201 as potential nonlinear optical (NLO) material and for the theoretical designing of novel NLO chromophores JK-D1–JK-D12. DFT/TDDFT calculations were performed to compute the effect of p-linkers and acceptors-steered modulation on electronic, photophysical and NLO properties of JK-201 and JK-D1–JK-D12. Results illustrate that computed kmax (484.74 nm) and experimentally calculated kmax (481 nm) of JK-201 was found in good agreement. Maximum red shifted absorption spectrum was observed in JK-D12 with 599.38 nm. JK-D1–JK-D12 showed narrow energy gap and broader absorption spectrum as compared to JK-201. NBO analysis con?rmed the formation of charge separation state due to robust range of electrons/charge transfer from donor to acceptor via p-bridge. Giant NLO response was observed in all compounds. Particularly, JK-D12 displayed surprisingly large hai and btot computed 1376.74 (a.u.) and 405,731.84 (a.u.) respectively. Although literature is ?ooded with D–p–A compounds investigated for their DSSCs properties, but research reports on their NLO properties and utilization as NLO materials are completely deserted. Our research will open new horizons to explore DSSCs materials for NLO applications. This theoretical framework also exposed that ?uorene-substituted chromophores are excellent NLO candidates for modern hi-tech applications.
关键词： D–p–A organic chromophores,Acceptor units,Molecular modeling,Density functional theory,NLO response properties,p-Conjugated linkers
更新于2025-09-23 15:22:29
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Humidity effect on adsorption kinetics of ammonia onto electrospun SnO <sub/>2</sub> nanofibers
摘要： Tin dioxide nanofibers were successfully synthesized by electrospinning homogeneous solution of SnCl4·5H2O in polyvinyl alcohol (PVA) and the potential of SnO2 nanofibers as ammonia sensing element at room temperature were also investigated. A logarithmic dependence of sensitivity on ammonia concentration was observed. We further investigate the effect of relative humidity between 0% and 70% on ammonia sensing performance of SnO2 nanofibers based conductometric sensor for the first time. Sensing experiments showed that both the baseline sensor current and the response-recovery characteristics of the SnO2 based sensor modified by pre humidification of sensing layer' surface. To study the adsorption kinetics pseudo first order and Elovich models was used and the first order kinetic model best describes the ammonia adsorption onto the SnO2 nanofibers for low concentrations (≤80 ppm) of ammonia, irrespective of humidity level. On the other hand, the results describe the best representation of Elovich model, as evidenced by the high correlation coefficients, for high concentrations of ammonia gas.
关键词： adsorption kinetics,humidity effect,ammonia sensing,electrospinning,response time
更新于2025-09-23 15:22:29
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Optical Response of Lumped-Element Kinetic-Inductance Detector Arrays
摘要： We present an analysis of the optical response of lumped-element kinetic-inductance detector arrays, based on the NIKA2 1 mm array. This array has a dual-polarization sensitive Hilbert inductor for directly absorbing incident photons. We present the optical response calculated from a transmission line model, simulated with HFSS and measured using a Fourier transform spectrometer. We have estimated the energy absorbed by individual component of a pixel, such as the inductor. The difference between the absorption efficiencies is expected to be 20% from the simulations. The Fourier-transform spectroscopy measurement, performed on the actual NIKA2 arrays, validates our simulations. We discuss several possible ways to increase the absorption efficiency. This analysis can be used for optimization of the focal plane layout and can be extended to other kinetic inductance detector array designs in millimeter, submillimeter, and terahertz frequency bands.
关键词： superconducting microresonator,optical response,millimeter astronomy,Kinetic inductance detector
更新于2025-09-23 15:22:29
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Discovery and Characterization of a Naturally Occurring, Turn-On Yellow Fluorescent Protein Sensor for Chloride
摘要： Fluorescent proteins have been extensively engineered and applied as optical indicators for chloride in a variety of biological contexts. Surprisingly, given the biodiversity of ?uorescent proteins, a naturally occurring chloride sensor has not been reported to date. Here, we present the identi?cation and spectroscopic characterization of the yellow ?uorescent protein from the jelly?sh Phialidium sp. (phiYFP), a rare example of a naturally occurring, excitation ratiometric, and turn-on ?uorescent protein sensor for chloride. Our results show that chloride binding tunes the pKa of the chromophore Y66 and shifts the equilibrium from the ?uorescent phenolate form to the weakly ?uorescent phenol form. The latter likely undergoes excited-state proton transfer to generate a turn-on ?uorescence response that is pH-dependent. Moreover, anion selectivity and mutagenesis in the chloride binding pocket provide additional evidence for the proposed chloride sensing mechanism. Given these properties, we anticipate that phiYFP, with further engineering, could be a new tool for imaging cellular chloride dynamics.
关键词： phiYFP,mutagenesis,chloride sensor,anion selectivity,turn-on fluorescence,pH-dependent,excitation ratiometric,fluorescent proteins
更新于2025-09-23 15:21:21
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High Performance Fluorescent Turn-On Probe for Amitriptyline Based on Hybrid Nanoassembly of Organic–Inorganic Nanoparticles
摘要： Fluorescence methods have gained enormous attention due to their ease in use, simplicity, selectivity and sensitivity. Fluorescent chemosensors respond instantly by converting molecular recognition to fluorescent signals. The consumption of pharmaceutical products by living beings is on great increase. The disposal of such compounds in the environment is a matter of great concern as these compounds enter aquatic environment and are showing accumulation in tissues of aquatic organisms. In the present study, we have utilized naphthalimide based receptors to fabricate organic nanoparticles. These ONPs were used for the development of hybrid nanoassemblies and the developed nanoassemblies were characterized with the help of TEM and DLS studies. The photophysical studies were performed and the hybrid assembly developed using receptor 2 demonstrated a turn-on fluorescence emission behaviour on binding with Amitriptyline. The present sensing system acted as promising candidate for determination of Amitriptyline among other contending drug molecules. The established system can recognize amitriptyline up to a detection limit of 48 nM in aqueous medium. Electrochemical recognition studies show binding of hybrid nanoassembly of receptor 2 with Amitriptyline with limit of detection of 21 nM.
关键词： Turn-On Probe,Fluorescent Organic Nanoparticles,Amitriptyline,Nanomolar Detection,Hybrid Nanoassembly
更新于2025-09-23 15:21:21
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A critical review on visible-light-response CeO2-based photocatalysts with enhanced photooxidation of organic pollutants
摘要： Organic pollutants’ treatment in wastewater has attracted extensive attention due to its degradation-resistance and potentially hazardous to human health. Some organic matters such as persistent organic pollutants (POPs) could exist in environment and resist to decomposition, which may cause chronic intoxication or even cancers. Because photocatalytic technique is efficient, nontoxic, and cost-effective to degrade organic pollutants, some semiconductors including TiO2 and ZnO as photocatalysts have aroused wide public concern. CeO2 has been reported as an efficient photocatalyst in contrast to TiO2 owing to its high oxygen storage, eco-friendly properties and photostability. But inefficient utilization of solar energy due to its intrinsic wide bandgap restrains its further application in real environmental pollutant treatment. In order to improve photocatalytic performances of CeO2, some modifications have been developed such as doping ions, coupling with semiconductor and construction of CeO2-based solid-solution. The purpose of this review is to introduce these techniques, reveals its fundamental mechanisms and the recent researches about photodegradation of organic pollutants in wastewater over CeO2-based photocatalysts. Besides, this review will evaluate the photocatalytic performance for organic pollutants and outlook the challenges and prospects in the future.
关键词： Modification,CeO2,Visible-light-response,Photodegradation,Organic pollutants
更新于2025-09-23 15:21:21
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Design of Microstrip Bandpass Filters Based on Stair-Step Patch Resonator
摘要： In this research article, single pole bandpass filter using stair-step patch topology based on symmetrical and asymmetrical step impedance resonators has been designed for industrial, scientific and medical (ISM) band application. This filter has been modeled by Microwave Office simulator using RT/Duroid substrate constant of 10.8, the substrate thickness of 1.27mm, loss tangent of 0.0023 and copper metallization thickness of 0.035 mm. To enhance the stopband levels of filter response, two microstrip bandpass filters have been designed as two-pole configurations based on edge, and cross-coupled stair-step patch resonators using the same simulator tool and substrate specifications. The proposed filters have compact sizes of (0.311λ(cid:2917)(cid:2925) x 0.233λ(cid:2917)(cid:2925)) for single pole filter, (0.578λ(cid:2917)(cid:2925) x 0.24λ(cid:2917)(cid:2925) )for two-pole edge coupled filter and (0.566λ(cid:2917)(cid:2925) x 0.234λ(cid:2917)(cid:2925))for two-pole cross-coupled filter designed at center frequencies of 2.4, 2.46 and 2.41 GHz respectively. These filters have interesting insertion loss and return loss magnitudes, narrow band frequency responses, second harmonic suppression and good stopband levels. Apart from ISM band applications, the proposed filters can be adopted in WLAN systems and Bluetooth applications for short range devices. The experimental results for designed filters are of good consistency with the simulations.
关键词： ISM band applications,stair-step patch resonator,filter compactness,narrow band frequency response,Microstrip bandpass filters,second harmonic frequency blocking
更新于2025-09-23 15:21:21