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Dewetting Metal Nanofilms—Effect of Substrate on Refractive Index Sensitivity of Nanoplasmonic Gold
摘要： The localized surface plasmon resonance (LSPR) sensitivity of metal nanostructures is strongly dependent on the interaction between the supporting substrate and the metal nanostructure, which may cause a change in the local refractive index of the metal nanostructure. Among various techniques used for the development of LSPR chip preparation, solid-state dewetting of nano?lms offers fast and cost effective methods to fabricate large areas of nanostructures on a given substrate. Most of the previous studies have focused on the effect of the size, shape, and inter-particle distance of the metal nanostructures on the LSPR sensitivity. In this work, we reveal that the silicon-based supporting substrate in?uences the LSPR associated refractive index sensitivity of gold (Au) nanostructures designed for sensing applications. Speci?cally, we develop Au nanostructures on four different silicon-based ceramic substrates (Si, SiO2, Si3N4, SiC) by thermal dewetting process and demonstrate that the dielectric properties of these ceramic substrates play a key role in the LSPR-based refractive index (RI) sensitivity of the Au nanostructures. Among these Si-supported Au plasmonic refractive index (RI) sensors, the Au nanostructures on the SiC substrates display the highest average RI sensitivity of 247.80 nm/RIU, for hemispherical Au nanostructures of similar shapes and sizes. Apart from the signi?cance of this work towards RI sensing applications, our results can be advantageous for a wide range of applications where sensitive plasmonic substrates need to be incorporated in silicon based optoelectronic devices.
关键词： refractive index sensitivity,metal nano?lm,localized surface plasmonic resonance,dewetting
更新于2025-09-11 14:15:04
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Comparison between 940 nm Laser Diode and Topical 5 % Potassium Nitrate for Tooth Desensitization. Randomized Controlled Clinical trial
摘要： Purpose: To compare the effectiveness of two dental desensitization therapies, 940nm laser diode and potassium nitrate, in patients with dental hypersensitivity (DH) symptoms. Methods: This randomized clinical trial included 30 patients who initially underwent basic periodontal therapy and presented gingival recessions Class I and II (Miller 1985) with symptoms of DH. Subjects were randomly assigned into two groups. The first group (n = 15) received laser 940 nm application for 90 seconds on the surface of the recession and were given a tube of glycerin to be applied daily in order to avoid generating bias. Patients in the second group (n = 15) were exposed to inactive laser simulating the actual application of the laser, and they were given a desensitizing gel containing 0.5 g of potassium nitrate to be applied twice daily during 14 days. Controls were carried out at 15 minutes, 8 days, 15 days, and 4 weeks. Data obtained were filled out in an Excel table. For comparison between groups the Mann Whitney U and t student tests were used (p=0.05). Results: All patients involve in the study experienced reduction in DH (p<0.01) and differences between the two interventions performed. Conclusions: Laser and nitrate therapies were effective to manage DH after basic periodontal therapy. However, a statistically significant higher sensitivity reduction was observed in laser therapy group.
关键词： diode laser,dentinal sensitivity,periodontal disease,gingival recession,potassium nitrate
更新于2025-09-11 14:15:04
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Chemo-treated 4T1 breast cancer cells radiation response measured by single and multiple cell ionization using infrared laser trap
摘要： We present a study that uses a laser trapping technique for measurement of radiation sensitivity of untreated and chemo-treated cancer cells. We used a human mammary tumor cell line (4T1) treated by an antitumor compound, 2-Dodecyl-6-methoxycyclohexa-2, 5-diene-1,4-dione (DMDD), which was extracted from the root of Averrhoa carambola L. The untreated control group, and both 2-hour and 24-hour treated groups of 4T1 cells were used in this study. The absorbed threshold ionization energy (TIE) and the threshold radiation dose (TRD) were determined using a high-power infrared laser (at 1064 nm) trap by single and multiple cells trapping and ionization. The results were analyzed using descriptive and t-statistics. The relation of the TIE and TRD to the mass of the individual cells were also analyzed for different hours of treatment in comparison with the control group. Both TIE and TRD decrease with increasing treatment periods. However, the TRD decreases with mass regardless of the treatment. Analyses of the TRD for single vs multiple cells ionizations within each group have also consistently showed this same behavior regardless of the treatment. The underlying factors for these observed relations are explained in terms of radiation, hyperthermia, and chemo effects.
关键词： threshold ionization energy,chemo-treated cancer cells,threshold radiation dose,4T1 breast cancer cells,laser trapping technique,DMDD,radiation sensitivity
更新于2025-09-11 14:15:04
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Role of Spectral Line Profile in Laser IR Analysis of Multicomponent Gas Mixtures
摘要： Topical issues of the quantitative analysis of multicomponent gas mixtures with use of laser absorption infrared technologies are addressed. It is shown that a number of questions exist regarding the detection of pollutants using these technologies, and these concern not only the position of the center of the analytical line of the detected substance but also the shape of its profile, especially in case of strong intermolecular interactions under conditions of open atmosphere. A number of examples show various aspects of the influence of the error of the spectroscopic model embedded in the solution of the inverse problem (the width and shape of the laser spectral line and gas absorption lines) on the determination of gas concentrations. The parameters of the sensitivity and selectivity of laser gas analysis that support making the optimal choice of laser radiation frequencies for studying specific gas mixtures are discussed. The importance of the high monochromaticity of laser lines, the smooth tuning of the radiation frequency over a wide spectral range, and the adequate simulation of the IR spectra of multicomponent gas mixtures are demonstrated.
关键词： multicomponent gas mixture,absorption line shape,intensity,quantitative laser analysis,sensitivity,model IR spectra,simulation parameters,selectivity
更新于2025-09-11 14:15:04
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Solar Photovoltaic Panels Combined with Energy Storage in a Residential Building: An Economic Analysis
摘要： Renewable energy is a wide topic in environmental engineering and management science. Photovoltaic (PV) power has had great interest and growth in recent years. The energy produced by the PV system is intermittent and it depends on the weather conditions, presenting lower levels of production than other renewable resources (RESs). The economic feasibility of PV systems is linked typically to the share of self-consumption in a developed market and consequently, energy storage system (ESS) can be a solution to increase this share. This paper proposes an economic feasibility of residential lead-acid ESS combined with PV panels and the assumptions at which these systems become economically viable. The profitability analysis is conducted on the base of the Discounted Cash Flow (DCF) method and the index used is Net Present Value (NPV). The analysis evaluates several scenarios concerning a 3-kW plant located in a residential building in a PV developed market (Italy). It is determined by combinations of the following critical variables: levels of insolation, electricity purchase prices, electricity sales prices, investment costs of PV systems, specific tax deduction of PV systems, size of batteries, investment costs of ESS, lifetime of a battery, increases of self-consumption following the adoption of an ESS, and subsidies of ESS. Results show that the increase of the share of self-consumption is the main critical variable and consequently, the break-even point (BEP) analysis defines the case-studies in which the profitability is verified.
关键词： sensitivity analysis,photovoltaic,self-consumption,storage,economic analysis
更新于2025-09-11 14:15:04
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Detection of IL-8 in human serum using surface-enhanced Raman scattering coupled with highly-branched gold nanoparticles and gold nanocages
摘要： Mesoporous materials are ideal carriers for guest molecules and they have been widely used in analytical science. The unique mesoporous structure provides special properties including large specific surface area, tunable pore size, and excellent pore connectivity. The structural properties of mesoporous materials have been largely made use of to improve the performance of analytical methods. For instance, the large specific surface area of mesoporous materials can provide abundant active sites and increase the probability of contact between analytes and active sites to produce stronger signals, thus leading to the improvement of detection sensitivity. The connections between analytical performances and the structural properties of mesoporous materials have not been discussed previously. Understanding the "structure–performance relationship" is highly important for the development of analytical methods with excellent performance based on mesoporous materials. In this review, we discuss the structural properties of mesoporous materials that can be optimized to improve the analytical performance. The discussion is divided into five sections according to the analytical performances: (i) selectivity-related structural properties, (ii) sensitivity-related structural properties, (iii) response time-related structural properties, (iv) stability-related structural properties, and (v) recovery time-related structural properties.
关键词： analytical science,stability,recovery time,response time,structure–performance relationships,selectivity,sensitivity,mesoporous materials
更新于2025-09-11 14:15:04
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Multiwalled carbon nanotube based aromatic volatile organic compound sensor: sensitivity enhancement through 1-hexadecanethiol functionalisation
摘要： Aromatic volatile organic compound (VOC) sensors are attracting growing interest as a response to the pressing market need for sensitive, fast response, low power consumption and stable sensors. Benzene and toluene detection is subject to several potential applications such as air monitoring in chemical industries or even biosensing of human breath. In this work, we report the fabrication of a room temperature toluene and benzene sensor based on multiwall carbon nanotubes (MWCNTs) decorated with gold nanoparticles and functionalised with a long-chain thiol self-assembled monolayer, 1-hexadecanethiol (HDT). High-resolution transmission electron microscopy (HRTEM) and Fourier transform infrared spectroscopy (FTIR) were performed to characterize the gold nanoparticle decoration and to examine the thiol monolayer bonding to the MWCNTs. The detection of aromatic vapours using Au-MWCNT and HDT/Au-MWCNT sensors down to the ppm range shows that the presence of the self-assembled layer increases the sensitivity (up to 17 times), selectivity and improves the response dynamics of the sensors.
关键词： multiwall carbon nanotubes (MWCNTs),vapour sensor,sensitivity,gold-decorated MWCNTs,self-assembled monolayers (SAMs),selectivity
更新于2025-09-11 14:15:04
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[IEEE 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Waikoloa Village, HI (2018.6.10-2018.6.15)] 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Cathodoluminescence Characterization of Semiconductor Doping at the Nanoscale
摘要： PVDF pyroelectric sensor was widely used in many fields. At present, the PVDF pyroelectric sensor has been applied for acoustic measurement. However, the effect of backing on the sensitivity of sensor was not particularly studied until now. In this paper, a Physical model was established in the finite element software. According to this model, the waveform of pyroelectric signal was predicted. By changing the parameters of the backing material, the influence of the backing on the sensitivity of the sensor was analyzed. It is confirmed that the Physical model is effective and the constant pressure heat capacity, attenuation coefficient and acoustic impedance of backing material directly affect the sensitivity of the sensor.
关键词： PVDF pyroelectric sensor,backing material,ultrasonic power,sensitivity
更新于2025-09-11 14:15:04
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Non-Hermitian ring?laser gyroscopes with enhanced Sagnac sensitivity
摘要： Gyroscopes are essential to many diverse applications associated with navigation, positioning and inertial sensing1. In general, most optical gyroscopes rely on the Sagnac effect—a relativistically induced phase shift that scales linearly with the rotational velocity2,3. In ring laser gyroscopes (RLGs), this shift manifests as a resonance splitting in the emission spectrum, which can be detected as a beat frequency4. The need for ever more precise RLGs has fuelled research activities aimed at boosting the sensitivity of RLGs beyond the limits dictated by geometrical constraints, including attempts to use either dispersive or nonlinear effects5–8. Here we establish and experimentally demonstrate a method using non-Hermitian singularities, or exceptional points, to enhance the Sagnac scale factor9–13. By exploiting the increased rotational sensitivity of RLGs in the vicinity of an exceptional point, we enhance the resonance splitting by up to a factor of 20. Our results pave the way towards the next generation of ultrasensitive and compact RLGs and provide a practical approach for the development of other classes of integrated sensor.
关键词： Sagnac sensitivity,Non-Hermitian,ultrasensitive sensors,ring laser gyroscopes,exceptional points
更新于2025-09-11 14:15:04
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Ruthenium decorated tungsten disulfide quantum dots for CO2 gas sensor
摘要： In this work, a selective chemi-resistive gas sensor for carbon dioxide gas detection at room temperature (~ 25 °C) was successfully fabricated, where ruthenium decorated tungsten disulfide (Ru@WS2) quantum dots (QDs) have been used as the sensing material. A mixed solvent of lithium hydroxide (LiOH·H2O) and N-Methyl-2-pyrrolidone (NMP) were used to obtain the Ru decorated WS2 QD from the exfoliated WS2 nanoflakes. Then the prepared WS2 QD and Ru@WS2 QD were confirmed using different material characterisation techniques. The gas sensors were then exposed to various concentration of CO2 gas in dry air condition. Also, the effect of humidity of both the sensors in 5000 ppm CO2 gas has been studied. The Ru@WS2 QDs based sensor showed superior sensitivity and good selectivity to CO2 gas in comparison with isopropanol, acetone, ethanol, methanol and benzene at room temperature than WS2 QD. The sensor showed an increase in resistance when exposed to CO2 gas ranging from 500 to 5000 ppm, indicating p-type characteristics. Ru@WS2 QD shows less effect at different humid condition compares to WS2 QD as a CO2 gas sensor.
关键词： Ruthenium decorated tungsten disulfide (Ru@WS2),Transition metal dichalcogenides (TMDC),Quantum Dot (QD),Sensitivity,Selectivity,Gas sensor
更新于2025-09-11 14:15:04