Deposition of hexagonal boron nitride thin films on silver nanoparticle substrates and surface enhanced infrared absorption

Silver nanoparticle thin films with different average particle diameters are grown on silicon substrates. Boron nitride thin films are then deposited on the silver nanoparticle interlayers by radio frequency （RF） magnetron sputtering. The boron nitride thin films are characterized by Fourier transform infrared spectra. The average particle diameters of silver nanoparticle thin films are 126.6, 78.4, and 178.8 nm. The results show that the sizes of the silver nanoparticles have effects on the intensities of infrared spectra of boron nitride thin films. An enhanced infrared absorption is detected for boron nitride thin film grown on silver nanoparticle thin film. This result is helpful to study the growth mechanism of boron nitride thin film.

Absorption Range and Energy Shift of Surface Plasmon in Au Monomer and Dimer

The resonance behaviors of local surface plasmon resonance in Au monomer and dimer are characterized sys- temically by electron energy loss spectroscopy in a scanning transmission electron microscope. The measured absorption range is about 20nm larger than the physical size of the Au nanoparticles and the resonance peak energy shows a red shift when the electron beam passes off the nanoparticles. The Au dimer displays similar behaviors. Numerical simulation also reproduces those experimental results.

Design and fabrication of structural color by local surface plasmonic meta-molecules

In this paper, we propose a new form of nanostructures with Al film deposited on a patterned dielectric material for generating structural color, which is induced by local surface plasmonic resonant(LSPR) absorption in sub-wavelengthindented hole/ring arrays. Unlike other reported results obtained by using focus ion beam(FIB) to create metallic nanostructures, the nano-sized hole/ring arrays in Al film in this work are replicated by high resolution electron beam lithography(EBL) combined with self-aligned metallization. Clear structural color is observed and systematically studied by numerical simulations as well as optical characterizations. The central color is strongly related to the geometric size, which provides us with good opportunities to dye the colorless Al surface by controlling the hole/ring dimensions(both diameter and radius), and to open up broad applications in display, jewelry decoration, green production of packing papers, security code,and counterfeits prevention.

A Complete Analysis of Clarity(C50)Using I-SIMPA to Maintain Ideal Conditions in an Acoustic Chamber

In any closed environment considered,it can be seen that the acoustic parameters are inherently not constant over the entire area considered.In a closed environment,it is ideally preferred to maintain the acoustic parameters as constant so that there exists better quality of sound leading to better auditory perception with respect to the audience.Practically,some of the acoustic parameters like reverberation time and clarity do not strictly pertain to the pattern obtained theoretically.In this paper,simulations are carried out using I-SIMPA under different values of Sound Transmission Class(STC),source position,distribution and the chamber dimensions and provides an insight into the behaviour of these acoustic parameters and the appropriate values that have to be infused into the system to build the chamber.The acoustic environment is modelled keeping an actual closed room in mind and testing is done with respect to different values of surface absorption coefficients(practically indicated using Sound Transmission Class)and dimensions to determine ideal conditions.

Synthesis of Au nanorods in a low pH solution via seed-media method

The gold （Au） nanorods with various aspect ratios are obtained by a seed-media method in low pH growth solution. Transmission electron microscopy （TEM） and UV-visible spectrophotometry are utilized to characterize the Au nanorods, and the longitudinal absorption peak positions of Au nanorods show different shifting trends of the growth evolutions in various low pH （1~3） solutions. Other influential factors on the shape of Au nanorod are also systematically studied under low pH reaction condition. The positions of longitudinal peak shift between 600 nm and 900 nm, with the aspect ratios of Au nanorods varying from 2 to 5 both in the simulation and experimental results. The simulation results are in agreement with experimental ones.

Experimental observation of surface phonon absorption in Zn fine particles coated with ZnO

FINE particles have attracted much attention in the past few years due to their unique physical and chemical properties. For gas-evaporated fine metallic particles, a thin oxide layer is usually formed on their surface. According to Ruppin’s prediction, a dielectric coating on metallic particles should have a series of surface modes between ωTO and ωLO, the long-wavelength transverse and longitudinal optical phonon frequencies of the dielectric. The frequency of

Unraveling the interfacial effect of PdBi bimetallic catalysts on promoting CO_(2)electroreduction to formate

Through interface engineering and content control strategy,a PdBi bimetallic interface structure was constructed for the first time to selectively convert CO_(2)to formate with a remarkably high Faraday efficiency(FEformate)of 94%and a partial current density(jformate)of 34 mA·cm^(−2)at−0.8 V vs.reversible hydrogen electrode(RHE)in an H-cell.Moreover,the PdBi interface electrocatalyst even exhibited a high current density of 180 mA·cm^(−2)with formate selectivity up to 92%in a flow cell and could steadily operate for at least 20 h.Electrochemical in-situ attenuated total reflection surface enhanced infrared absorption spectroscopy(ATR-SEIRAS)confirmed that the PdBi interface could greatly weaken the adsorption of*CO intermediates due to electronic and geometric effects.Density functional theory(DFT)calculations also established that the PdBi interface regulated the CO_(2)-to-formate pathway by reducing the energy barrier toward HCOOH and largely weakening the adsorption of*CO intermediates on the catalyst surface.This study reveals that the unique PdBi bimetallic interface can provide a novel platform to study the reaction mechanism through combining in-situ ATR-SEIRAS and DFT calculations.

Illumination-dependent free carrier screening effect on the performance evolution of ZnO piezotronic strain sensor

Performance modulation of ZnO optoelectronic devices in the presence of proper piezoelectric polarization charges has been widely reported, whereas relatively less work has been performed about the influence of photoexcitation on piezotronics. In this stud~ we experimentally investigated the performance evolution of ZnO piezotronic strain sensor under various 365 nm UV irradiation densities. The device demonstrated a response ratio of -200 under no illumination and under -0.53% compressive strain, and the response time is approximately 0.3 s. However, tremendous performance degradation was observed with the increase in the illumination densi~, which is attributed to the W-modulated change in the free electron concentration and Schottky barrier height. It was observed that increased carrier density intensifies the screening effect and thus, the modulation ability of piezo-polarization charges weakens. Meanwhile, the deterioration of rectifying behavior at the interface under UV illumination also jeopardizes the device performance.

Characteristics and application of road absorbing solar energy

If the heat of road surface can be stored in summer, the road surface temperature will be decreased to prevent permanent deformation of pavement. Besides, if the heat stored is released, it can supply heat for buildings or raise the road surface temperature for snow melting in winter. A road-solar energy system was built in this study, and the heat transfer mechanism and effect of the system were analyzed according to the monitored solar radiant heat, the solar energy absorbed by road and the heat stored by soil. The results showed that the road surface temperature was mainly affected by solar radiation, but the effect is hysteretic in nature. The temperature of the solar road surface was 3~C-6~C lower than that of the ordinary road surface. The temperature of the solar road along the vertical direction was 2~C-5~C lower than that of the ordinary road. The temperature difference increased as the distance to the heat transfer tubes decreased. The average solar collector efficiency of the system was 14.4%, and the average solar absorptivity of road surface was 36%.

Novel advances in metal-based solar absorber for photothermal vapor generation

Access to safe drinking water has become an extremely urgent research topic wo rldwide.In recent years,the technology of solar vapor generation has been extensively explored as a potential and effective strategy of transforming elements content in seawater.In this review,the basic concepts and theories of metal-based photothermal vapor generation device(PVGD) with excellent optical and thermal regulatory are introduced.In the view of optical regulation,how to achieve high-efficiency localized evaporation in different evaporation system(i.e.,volumetric solar heating and interface solar heating) is discussed;from the aspect of thermal regulation,the importance of selective absorption surface for interfacial PVGD is analyzed.Based on the above discussion and analysis,we summarize the challenges of metal-based desalination device.

Source and Control of Nitrogen for X70 Pipeline Steel

The effects of some key factors on nitrogen absorption during the smelting process of X70 pipeline steel were studied,and the source of nitrogen pick-up was analyzed to find the bottleneck for nitrogen control.A series of measures were put forward to decrease the nitrogen pick-up.The results indicated that an exponential relationship existed between the nitrogen absorption index and the free oxygen in molten steel.Nitrogen absorption index could decrease below 0.3when free oxygen in molten steel was above 100×10^（-6） after tapping.For low sulfur killed steel,the nitrogen absorption ratio and sulfur content satisfied a linear relationship with a slope of-0.007.Low free-oxygen and sulfur were beneficial to the deep desulfurization during vacuum treatment.The contradiction of high desulfurization ratio and low nitrogen pick-up during LF process could be resolved by skimming oxidizing slag after tapping and making new high basicity top slag.After optimization,the average content of nitrogen in final product decreased from 46×10（-6）to 35×10（-6）.