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Experimental Application of Piezoelectric Actuator-Driven Pulsed Water Jets in Retinal Vascular Surgery
摘要： To report on the effectiveness and safety of an ophthalmic piezoelectric actuator-driven pulsed water jet (ADPJ) system adapted for intraocular use. Methods: First, we determined the highest ADPJ flow rate that did not cause an unsafe rise in intraoperative intraocular pressure (IOP) in rabbits (n ? 4). Next, we determined the most effective ADPJ frequency (in hertz) at that flow rate. Finally, we visualized the ADPJ stream, measured its pressure, and determined the minimum voltage and distance between the ADPJ needle and retinal veins to induce intravenous displacement of the blood column (DBC) through massage of the outer retinal vessels (n ? 3) while not causing retinal tearing or hemorrhage. Results: We found that a 0.05 mL/min ADPJ flow rate caused IOP to rise above 40 mm Hg after 1 minute, but that at 0.025 mL/min, IOP stayed below 40 mm Hg even after 3 minutes. Moreover, we found that a 0.025 mL/min ADPJ stream was stable at a pulse frequency of 10 Hz and that at this flow rate/frequency the ADPJ pressure was closely correlated with the applied voltage (P , 0.001, r2 ? 0.9991). The minimum voltage and distance to achieve intravenous DBC without causing retinal tearing or hemorrhage were 40 V and 0.5 mm, respectively. Conclusions: With an appropriate flow rate and surgical time, ADPJ successfully induced massage of the retinal vessels and intravenous DBC while maintaining safe IOP and not causing retinal complications. Translational Relevance: The ADPJ system has promise as a safe and minimally invasive instrument for the intraocular surgical treatment of human retinal vascular diseases.
关键词： intraocular pressure,retinal complication,retinal vascular surgery,piezoelectric actuator-driven pulsed water jet,retinal vein occlusion
更新于2025-09-04 15:30:14
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Leaf Water Status from Lab Estimates of VIS-NIR Reflectance and Transmittance
摘要： Remotely sensing the water status of plant canopies remains a long term goal of remote sensing research. Established approaches involve measurements in the thermal infrared and the 900-2000nm reflective infrared. Less popular UV-visible-NIR techniques presumably deserve research attention, because photochemical changes linked to plant water status manifest spectral light scattering and absorption changes. Here we estimated the visible and NIR light reflected from the leaf interior and the leaf transmittance of corn (Zea mays L.) leaves having a range of relative water contents. Our results highlight the importance of both scattering effects and effects due to absorption by leaf pigments.
关键词： leaf reflectance,leaf relative water content,RWC,leaf transmittance
更新于2025-09-04 15:30:14
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Remote Sensing Inversion of Water Quality Parameters in Longquan Lake Based on PSO-SVR Algorithm
摘要： The paper uses the PSO-SVR algorithm to inverse the water quality parameters based on GF-1 remote sensing image in Longquan lake where is located in Chengdu, Sichuan Province. Longquan Lake is a key drinking water source in Chengdu, so its water quality is very critical. Particle swarm optimization (PSO) optimizes the parameters of the support vector regression (SVR) inversion model to establish the new PSO-SVR inversion model, and PSO can effectively improve the efficiency and the accuracy of the SVR inversion model. At the same, the empirical inversion model was established by using the measured hyperspectral data and concentration of water quality parameters. Comparing with SVR inversion model, PSO-SVR inversion model achieves a better result in the application of suspended solids and Chlorophyll concentration inversion.
关键词： GA-SVM,Support vector machine,Water quality inversion,Genetic algorithm,Suspended solids
更新于2025-09-04 15:30:14
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Solvothermal Synthesis and Characterization of Flower-Like b-In2S3 Microparticles
摘要： Flower-like β-In2S3 particles have been successfully synthesized via solvothermal process by using acetylacetone-water solvent mixture. The products were characterized by X-ray diffraction, scanning electron microscopy, reflectance spectra. X-ray diffraction analysis confirms the formation of cubic β-In2S3. Microstructural investigation with SEM indicated that the particle size increases with increasing reaction time. The optical band gap determined from reflectance spectra was found to have values within the range of 2.34-2.49 eV.
关键词： Microstructure,Solvothermal synthesis,Optical properties,β-Indium sulphide,Acetylacetone-water solvent system
更新于2025-09-04 15:30:14
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Hyperspectral Retrieval of Canopy Water Content Through Inversion of the Beer-Lambert Law
摘要： The retrieval of quantitative equivalent water thickness on canopy level (EWTc) is an agriculturally important task for hyperspectral remote sensing. In this study the Beer-Lambert law is applied to inversely determine water content from measured winter wheat spectra collected in 2015 and 2017. The spectral model is calibrated using a look-up-table (LUT) of 50.000 PROSPECT spectra. Validation was performed using two leaf optical properties datasets (LOPEX93 and ANGERS) and in-situ data acquired in Southern Germany. After considering destructive in-situ water content measurements separately for leaves, stems, and fruits, results indicate optically active plant water by plant component in the 930 to 1060 nm range of canopy reflectance. Results for spectrally derived EWTc were most promising for leaves and ears reaching coefficients of determination up to 0.75 and a normalized RMSE (nRMSE) of 24% between measured and estimated canopy water content.
关键词： EnMAP,hyperspectral,agriculture,canopy water content,spectroscopy
更新于2025-09-04 15:30:14
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Improvement of the Degradation of Methyl Orange Using a TiO2/BDD Composite Electrode to Promote Electrochemical and Photoelectro-Oxidation Processes
摘要： Electrophoretic deposit of titanium dioxide (TiO2) was carried out over a boron doped diamond plate of 2 cm2, annealing at 350 °C to produce binary TiO2/BDD composite electrode. The composite was characterized by scanning electron microscopy (SEM) and linear sweep voltammetry (LSV) response. N,N-dimethyl-p-nitrosoaniline (RNO) was used as a probe molecule for the detection of free radicals (?OH) during the oxidation of water in phosphate buffer (pH 4) solution; at the TiO2/BDD/hv composite, an apparent first-rate kinetic constant of kobs = 0.1314 min-1 was observed. Afterwards, the composite electrode was applied to degrade 40 and 100 mg L-1 of a typical azo dye methyl orange (MO) via electrochemical process, such as: electro-oxidation (EO) and photoelectro-oxidation (PEO) under 25, 75 and 125 mA cm-2 current density (j); the PEO tests were performed using a UVA lamp at 365 nm. Results showed that the discoloration in the PEO process was larger than in the EO process, 96 and 100 %, respectively. Chemical Oxygen Demand (COD) was tested to evaluate the degradation. Hydroxylated derivatives were identified by means of mass spectroscopy during the PEO of MO in a TiO2/BDD/hv composite electrode.
关键词： TiO2/BDD composite,electrochemical process,hydroxyl radical formation,azo dye,water treatment
更新于2025-09-04 15:30:14
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Electrodeposition and characterization of SnS-electrochemically reduced graphene oxide heterojunction
摘要： This work shows the formation of a heterojunction between tin (II) sulfide (SnS) and electrochemically reduced graphene oxide (ERGO) carried out through two electrochemical steps. In the first step, graphene oxide (GO) was electrochemically reduced on a fluorine-doped tin oxide (FTO) electrode. In the second step, the ERGO/FTO substrate was used as an electrode for the electrodeposition of SnS. In this study, each material electrodeposited (ERGO, SnS and SnS/ERGO heterojunction) was analyzed and characterized using different techniques, which confirmed the SnS/ERGO heterojunction formation. By employing electrochemical impedance spectroscopy (EIS) and linear sweep photovoltammetry measurements, it was confirmed that SnS deposited in both, bare FTO and ERGO, is a p-type semiconductor. Furthermore, an improvement of the photocatalytic properties of the SnS/ERGO photocathode in comparison with the SnS film was observed. This effect is related to the ERGO interlayer between the SnS film and the FTO electrode, and the structural and morphology modification of the SnS film onto ERGO.
关键词： semiconductors,electrodeposition,water splitting,graphene oxide,thin films
更新于2025-09-04 15:30:14
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[IEEE 2018 15th European Radar Conference (EuRAD) - Madrid, Spain (2018.9.26-2018.9.28)] 2018 15th European Radar Conference (EuRAD) - A Real-Time Non-Destructive Water Status Monitoring System at Terahertz Band
摘要： A novel water content monitoring system of a grapevine based on the reflectivity measurement on the plant trunk at the terahertz band is presented. In order to simulate different outdoor conditions, mainly temperature and lighting, the whole setup, which includes the grapevine and the measurement system, has been settled inside a growth chamber. Fluctuations of lighting conditions, temperature and irrigation have been correlated with variations of the signal power reflected on the trunk using both time domain broadband measurements and, frequency domain narrowband magnitude and phase measurements. The innovative setup enables the achievement of more reliable and accurate results when external conditions vary. Finally, the results have been contrasted, with high level of correlation, with long-established techniques using a dendrometer and a humidity probe.
关键词： xylem water content,reflectometry,dielectric constant,terahertz radiation
更新于2025-09-04 15:30:14
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Investigation of the Combined Efficiency of a Solar/Gas Hybrid Water Heating System
摘要： In climate regions with large seasonal variations in solar radiation, such as the Pacific Northwest of the United States, a solar thermal energy collector might not economically satisfy year-round domestic water heating demands, requiring an auxiliary unit, such as a natural gas-fired water heater. Previous studies have shown that the burner efficiency of a gas-fired water heater varies depending on the log-mean temperature difference between the cold fluid (water) and the hot fluid (combustion gases). In a solar/gas hybrid water heating system where solar collectors are used in conjunction with a gas-fired heater, the partial heating of water provided by solar input reduces the log-mean temperature difference value for the gas heater, reducing the efficiency of the gas burner. Since this efficiency reduction varies depending on the amount of pre-heating provided by solar energy input, it is difficult to accurately predict the actual cost and energy savings offered by solar/gas hybrid water heaters in different climate scenarios. Hence, to predict the actual energy and cost savings under various design conditions, the performance of solar/gas hybrid systems must be better understood. The purpose of this work is to experimentally determine the thermal performance of a solar/gas water hybrid water heating system with a 6.44 m2 flat plate solar collector array and a 22.3 kW natural gas burner in Corvallis, Oregon. Under different temperature lifts and solar insolation values, the system was operated at three different modes of heating: solar, gas, and combined solar/gas mode. The overall system thermal efficiency value for each mode is calculated. The efficiency of the solar collector heating system was found to be 41.97%, 39.82%, and 35.05% at initial water temperature of 20, 30, and 51.5 °C, respectively. For initial water temperatures of 20, 30, and 51.5 °C, the efficiency of the gas burner was found to be 69.2%, 66.4%, and 65.5% at the HHV, and 76.7%, 73.6%, and 72.6% at the LHV of natural gas, respectively. In the combined solar/gas heating mode, the efficiency of the gas burner decreased with increasing solar fraction. For solar fractions of 4.93%, 9.40%, 11.39%, and 14.27%, the efficiency of the gas burner in terms of the HHV of natural gas was found to be of 69.08%, 66.80%, 66.17%, and 65.18%, respectively. Based on the experimental results, a configuration that would provide higher overall system efficiency for combined solar/gas heating is suggested.
关键词： water heating,Solar thermal,natural gas
更新于2025-09-04 15:30:14
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Carbon nanosheet facilitated charge separation and transfer between molybdenum carbide and graphitic carbon nitride toward efficient photocatalytic H2 production
摘要： Interfacial manipulation of nanostructured heterojunction photocatalysts to enhance charge separation and transfer is highly desirable to achieve a high photocatalytic activity. In this work, a well-designed non-noble-metal Mo2C@C/g-C3N4 heterostructure is constructed, in which the intercalated carbon nanosheets serve as a binder to form an excellent interfacial contact between Mo2C and g-C3N4. In addition, large quantities of carbon quantum dotsare found to be homogeneously embedded in the carbon nanosheets. The as-obtained Mo2C@C/g-C3N4 hybrid exhibits a remarkably improved photocatalytic H2 evolution rate of 52.1 μmol h?1 under visible-light irradiation (λ ≥ 420 nm) without co-catalyst, which is up to nearly 260 times higher than that of pristine g-C3N4 (0.2 μmol h?1) under the same conditions. The significant increase in photocatalytic activity mainly results from the fast charge migration and separation between Mo2C and g-C3N4 facilitated by the conducting carbon nanosheets as an efficient electron mediator. Moreover, the carbon quantum dots embedded in the carbon support also promotes solar energy utilization. This work highlights a feasible strategy to explore highly efficient photocatalysts via interfacial engineering on heterojunction composites.
关键词： H2 evolution,Photocatalysis,Water splitting,Carbon nitride,Heterojunction
更新于2025-09-04 15:30:14