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Facial synthesis of a novel Ag <sub/>4</sub> V <sub/>2</sub> O <sub/>7</sub> /g‐C <sub/>3</sub> N <sub/>4</sub> heterostructure with highly efficient photoactivity
摘要： A novel Ag4V2O7/g-C3N4 heterostructure was synthesized by a facial etching method in ammonia solution using Ag2VO2PO4/g-C3N4 as a self-sacrifice precursor. With the concentration of ammonia solution increasing from 0.05 to 0.2 M, phase transformation took place, described as: Ag2VO2PO4/g-C3N4 → Ag2VO2PO4/Ag4V2O7/g-C3N4 → Ag4V2O7/g-C3N4. Compared with pristine Ag2VO2PO4/g-C3N4, the etched samples of Ag4V2O7/g-C3N4 and Ag2VO2PO4/Ag4V2O7/g-C3N4 exhibited dramatically improved activity for the degradation of methylene blue (MB), methyl orange (MO) and imidacloprid under visible light irradiation. When etched with 0.15 M ammonia solution, an Ag4V2O7/g-C3N4 heterostructure was obtained that exhibited the highest photoactivity. This photocatalyst was nearly 9.1, 3.0, and 24.3 times more efficient than pristine Ag2VO2PO4/g-C3N4 for degradation of MB, MO and imidacloprid, respectively. The excellent photocatalytic performance can be ascribed to the as-obtained well-defined Ag4V2O7/g-C3N4 heterojunction, which improves the separation and transfer efficiency and prolongs the lifetime of photoinduced charges. In addition, the stability and dominant radicals were investigated.
关键词： photocatalyst,heterostructure,Ag4V2O7/g-C3N4,visible light
更新于2025-09-04 15:30:14
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Low-Cost Integrated Zinc Oxide Nanorods Based Humidity Sensors for Arduino Platform
摘要： Realization of a simple integrated and low-cost intensity modulation/direct detection (IM/DD) based humidity and vapor detection system utilizing zinc oxide (ZnO) nanorods as the active material is demonstrated. The sensing device comprises of ZnO nanorods optimally grown on a glass substrate and mounted on 3D printed platform for the alignment with a green light-emitting diode (LED) set-up for edge excitation. An Arduino platform was used for signal processing of the detection of the transmitted light. Both forward and backward scattering are affected due to light leakage while propagating through the glass substrate that are further attenuated in the presence of humidity. In this work, backward scattering was found to be dominant and thus with increasing humidity a reduction in the transmitted light was monitored. When the sensor was tested in a humidity controlled environment, it was found that the output voltage drops by approximately 750 mV upon changing the relative humidity (RH) level from 35% to 90% in a non-linear fashion. The average sensitivity of the sensor was observed to be -12 mV/% throughout the tested RH levels. Sensitivity was found to be higher at -24.6 mV/% for RH’s beyond 70%. An average response time of 3.8 s was obtained for RH levels of 85% with respect to the standard ambient humidity conditions (RH 50%), which showed a quicker recovery time of 2.2 s. The proposed sensor device provides numerous advantages including low cost production, simplicity in design, ease of use and stability during handling.
关键词： light scattering,humidity sensor,nanorods,fast sensing,zinc oxide,arduino
更新于2025-09-04 15:30:14
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Improved Smartphone-based Indoor Pedestrian Dead Reckoning Assisted by Visible Light Positioning
摘要： Aiming at the problem of heavy preparation work and high cost of indoor positioning technology, this paper proposes (VLP)-assisted smartphone-based pedestrian dead reckoning (PDR) indoor positioning technology. This technology combines the advantages of both PDR and VLP algorithms for indoor positioning. During the pedestrian position calculation, the method of using the averaging of mode to process the heading angle data is creatively used, which improves the positioning accuracy and increases reliable operation time. At the same time, the two-level verification method consisting of cyclic redundancy check and range constraint is implemented for VLP, which uses a LED carrying a modulation code as a beacon for absolute position and the camera of smartphone to capture/decode the LED image to obtain the absolute position and periodically correct the position of the PDR positioning, thereby avoiding the accumulation of PDR positioning technology errors. The scope and reliability of PDR are demonstrated. Experiments show that this method is a kind of low-cost, high-robust, high-precision indoor positioning technology.
关键词： Visible light positioning,Pedestrian dead reckoning,Indoor location
更新于2025-09-04 15:30:14
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Mitochondrial Fission Is Required for Blue Light-Induced Apoptosis and Mitophagy in Retinal Neuronal R28 Cells
摘要： Light emitting diodes (LEDs) are widely used to provide illumination due to their low energy requirements and high brightness. However, the LED spectrum contains an intense blue light component which is phototoxic to the retina. Recently, it has been reported that blue light may directly impinge on mitochondrial function in retinal ganglion cells (RGCs). Mitochondria are high dynamic organelles that undergo frequent fission and fusion events. The aim of our study was to elucidate the role of mitochondrial dynamics in blue light-induced damage in retinal neuronal R28 cells. We found that exposure to blue light (450 nm, 1000 lx) for up to 12 h significantly up-regulated the expression of mitochondrial fission protein Drp1, while down-regulating the expression of mitochondrial fusion protein Mfn2 in cells. Mitochondrial fission was simultaneously stimulated by blue light irradiation. In addition, exposure to blue light increased the production of reactive oxygen species (ROS), disrupted mitochondrial membrane potential (MMP), and induced apoptosis in R28 cells. Notably, Drp1 inhibitor Mdivi-1 and Drp1 RNAi not only attenuated blue light-induced mitochondrial fission, but also alleviated blue light-induced ROS production, MMP disruption and apoptosis in cells. Compared with Mdivi-1 and Drp1 RNAi, the antioxidant N-acetyl-L-cysteine (NAC) only slightly inhibited mitochondrial fission, while significantly alleviating apoptosis after blue light exposure. Moreover, we examined markers for mitophagy, which is responsible for the clearance of dysfunctional mitochondria. It was found that blue light stimulated the conversion of LC3B-I to LC3B-II as well as the expression of PINK1 in R28 cells. Mdivi-1 or Drp1 RNAi efficiently inhibited the blue light-induced expression of PINK1 and co-localization of LC3 with mitochondria. Thus, our data suggest that mitochondrial fission is required for blue light-induced mitochondrial dysfunction and apoptosis in RGCs.
关键词： mitophagy,apoptosis,mitochondrial fission,blue light,retinal neuronal cells
更新于2025-09-04 15:30:14
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[IEEE 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Atlanta, GA, USA (2017.10.21-2017.10.28)] 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Characterization of Stilbene Scintillation Detectors with Light Guide Coupling and Silicon Photomultiplier Readout
摘要： We experimentally investigated the low energy pulse shape discrimination (PSD) capabilities of four cubic stilbene crystals with 6 mm, 10 mm, 15 mm, and 20 mm sides. We used a 6 × 6 mm2 silicon photomultiplier (SiPM) for readout, and coupled the crystals both with and without light guides, optimizing light guide wrapping for PSD. We compared the crystals’s figure of merit (FOM) dependence on light output. For the smaller three crystals, direct coupling provided better PSD (roughly 116% FOM of the guided at 100 ? 150 keVee). For the 10 mm sided crystal the trend was reversed and the light guide became advantageous (105% FOM of the direct at 100 ? 150 keVee).
关键词： organic scintillator,stilbene,Pulse shape discrimination,light guide
更新于2025-09-04 15:30:14
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Photodetachable Adhesion
摘要： Peeling from strong adhesion is hard, and sometimes painful. Herein, an approach is described to achieve both strong adhesion and easy detachment. The latter is triggered, on-demand, through an exposure to light of a certain frequency range. The principle of photodetachable adhesion is first demonstrated using two hydrogels as adherends. Each hydrogel has a covalent polymer network, but does not have functional groups for bonding, so that the two hydrogels by themselves adhere poorly. The two hydrogels, however, adhere strongly when an aqueous solution of polymer chains is spread on the surfaces of the hydrogels and is triggered to form a stitching polymer network in situ, in topological entanglement with the pre-existing polymer networks of the two hydrogels. The two hydrogels detach easily when the stitching polymer network is so functionalized that it undergoes a gel–sol transition in response to a UV light. For example, two pieces of alginate–polyacrylamide hydrogels achieve adhesion energies about 1400 and 10 J m?2, respectively, before and after the UV radiation. Experiments are conducted to study the physics and chemistry of this strong and photodetachable adhesion, and to adhere and detach various materials, including hydrogels, elastomers, and inorganic solids.
关键词： hydrogels,light-triggered,photodetachable adhesion,topological
更新于2025-09-04 15:30:14
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Self‐Regulating Capabilities in Photonic Robotics
摘要： Traditional robots are machines programmed to accomplish tasks, thanks to a complex ensemble of sensors connected to a computer “brain” which elaborate signals to drive specific actions. This complex network suffers from limitations—the need for a central computer, for instance, poses a limit to device miniaturization and requires a large amount of energy. A promising development, made possible by recent advances in material science, endeavors a new generation of soft robots that are multifunctional, compliant, and autonomous in ways that are similar to biological organisms. In particular, photoresponsive polymers are demonstrated to be valid candidates to substitute the computer-based intelligence with an “intrinsic” material cleverness. First demonstrations of self-sustained motions as oscillations or autonomous walking are described. In these cases, light also provides a solution to a second, very important, issue in microrobotics, which is the availability of a source of energy. Light actuation together with smart polymers can be combined into self-controlled robots capable of simple decision-making processes, for example with robotic grippers that are able to distinguish particles with different colors. In addition, the most recent examples about the integration of a form of robotic “intelligence” into a single material with a minimal level of consciousness are reported.
关键词： smart soft robotics,self-sustained motions,light responsive polymers,autonomous decisions,photonic robotics
更新于2025-09-04 15:30:14
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Experimental Evidence for “Hot Exciton” Thermally Activated Delayed Fluorescence Emitters
摘要： Contradiction between no effective photophysical experiments and high device results causes the “hot exciton” thermally activated delayed fluorescence (TADF) mechanism to be still a controversial question. Here, the steady and transient photophysical characterization combined with theoretical calculation based on 4,7-bis(9,9-dimethyl-9H-fluoren-2-yl)-5,6-difluorobenzo[c][1,2,5]thiadiazole (2F-BTH-DMF), 4,7-bis(9,9-dimethyl-9H-fluoren-2-yl)benzo[c][1,2,5]thiadiazole (BTH-DMF), and 5,6-bis(9,9-dimethyl-9H-fluoren-2-yl)benzo[c][1,2,5] thiadiazole (o-BTH-DMF) demonstrate that all the emitters exhibit TADF via reverse intersystem crossing (RISC) from “hot exciton” triplet excited state. The fast RISC process “hot exciton” mechanism affords a very short delayed lifetime (1 μs). Organic light-emitting diodes (OLEDs) based on these emitters exhibit high exciton utilization over 25% and the best device shows a maximum current efficiency of 31.02 cd A?1, maximum power efficiency of 27.85 lm W?1, and external quantum efficiency of 9.13%, which are the highest performances for reported OLEDs with “hot exciton” mechanism. The experimental evidence for fast RISC process via “hot exciton” triplet state and short delayed lifetime highlights the TADF emitters with “hot exciton” mechanism for high-performance OLEDs with very low efficiency roll-off.
关键词： hot excitons,reverse intersystem crossing,thermally activated delayed fluorescence,organic light-emitting devices
更新于2025-09-04 15:30:14
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Recording Raman Spectra Using a Dynamic Fourier Transform Spectrometer
摘要： We have developed a dynamic Fourier transform spectrometer for recording Raman spectra in the near-IR range (800–1100 nm). Stability and reliability of operation of the spectrometer is achieved by using corner re? ectors in the design as mirrors in the main channel. In order to record a weak Raman signal, we set up a white light channel in the spectrometer which enables locking into the zero optical path difference when summing the interferograms over several scans. A reference channel with sampling frequency λ/4 lets us improve the sampling accuracy and the signal-to-noise ratio of the emission spectra. Using our spectrometer, we recorded the Raman spectra of test substances with known positions of the emission lines: 1,4-bis(5-phenyl-2-oxazolyl)benzene (POPOP, C24H16N2O2), stilbene (C14H12), acetylsalicylic acid (C9H8O4). Comparison of the POPOP Raman spectra obtained on the dynamic Fourier transform spectrometer and a diffraction spectrometer for the same experimental conditions showed that they qualitatively matched, and the time required to record the spectrum on the dynamic Fourier transform spectrometer was 4 times shorter.
关键词： Raman spectroscopy,dynamic Fourier transform spectrometer,white-light channel,Fourier transform spectrometer in the visible and near-IR ranges,corner re? ector
更新于2025-09-04 15:30:14
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A Perspective on the Mechanism of the Light-Rise of the Electrooculogram
摘要： The light-rise of the electrooculogram is believed to originate from a substance released from the rods after dark adaptation. The identity of this "elusive" light-rise substance has not been demonstrated, and therefore a new perspective on the light-rise is presented. The light-rise is caused by the depolarization of the basolateral membrane of the retinal pigment epithelium (RPE) has become clearer in the last decade with the identification of calcium as the intracellular secondary messenger and the role of bestrophin as a regulator of intracellular stores of calcium and controlling the cytosolic calcium levels through L-type calcium channels. The light-rise depends upon a change from darkness to light, which triggers the intracellular cascade resulting in the depolarization of the basolateral membrane. The same intracellular signaling molecules, notably calcium and inositol triphosphate (IP3), are strongly implicated in this cascade. Recent studies have now led to a clearer understanding of the roles and functions of the ion channels and their contribution to the light-rise with IP3 regulating the release of calcium for intracellular stores. Given that calcium and IP3 are also regulators of phagocytosis, and that the initiation of rod outer segment phagocytosis is initiated with light-onset, it may be that the light-rise is generated in response to this physiological event. Therefore, the putative light-rise substance may not be released by the rods, but follow directly from IP3 release from the RPE’s phospholipid membrane following the onset of light and the initiation of phagocytosis. The light rise substance, could be considered to be light itself.
关键词： inositol triphosphate,light-rise,electrooculogram
更新于2025-09-04 15:30:14