Relationship Between Thermal Stability and Optical Bandgap of Fluorinated Amorphous Carbon Films

Fluorinated amorphous carbon films were deposited using microwave electron cyclotron resonance chemical vapor deposition (ECR-CVD) reactor with CF4 and C8H6 as source gas and were annealed in nitrogen ambience for the investigating of their thermal stability .The relative concentration of C=C bond and optical bandgap were obtained by Fourier Transform Infrared (FTIR) spectroscopy and Ultraviolet-Visible (UV-VIS ) spectrum, respectively. It has been demonstrated that there is a close relationship between relative concentration of C=C bond and optical bandgap, and the films deposited at a higher microwave power have a lower optical bandgap and a better thermal stability.

Control of gain and thermal carrier loss profiles for mode optimization in 980-nm broad-area vertical-cavity surface-emitting lasers

Optical gain and thermal carrier loss distributions regarding current diffusion and various electric contact areas are investigated to improve the near-field modes from the ring-shape to a Gaussian-like configuration for extra-broad-area and oxide-confined vertical-cavity surface-emitting lasers. In this work an equivalent circuit network model is used. The resistance of the continuously-graded distributed Bragg reflectors （DBRs）, the current diffusion and the temperature effect due to different electric-contact areas are calculated and analyzed at first, as these parameters affect one another and are the key factors in determining the gain and thermal carrier loss. Finally, the gain and thermal carrier loss distributions are calculated and discussed.

Oversample Reconstruction Based on a Strong Inter-Diagonal Matrix for an Optical Microscanning Thermal Microscope Imaging System

Based on a strong inter-diagonal matrix and Taylor series expansions,an oversample reconstruction method was proposed to calibrate the optical micro-scanning error. The technique can obtain regular 2 ×2 microscanning undersampling images from the real irregular undersampling images,and can then obtain a high spatial oversample resolution image. Simulations and experiments show that the proposed technique can reduce optical micro-scanning error and improve the system＇s spatial resolution. The algorithm is simple,fast and has low computational complexity. It can also be applied to other electro-optical imaging systems to improve their spatial resolution and has a widespread application prospect.

Full potential study of HoMg

In this paper,HoMg is studied in two different phases i.e.B1 and B2.The calculated lattice constants in B1 and B2 phases are 6.39°A and 3.78°A and corresponding energies are−25,648.49 Ry and−25,648.56 Ry,respectively.It is more stable in B2 phase(Pm-3m configuration with no.221).The analysis of the obtained band structure and density of states shows metallic character of HoMg.Detailed information about the elastic properties is also presented in this paper.The calculated values of Cauchy pressure,G/B and Poisson ratio are−10.72,0.58 and 0.26,respectively which indicates that HoMg have brittle character.Calculations for the optical spectra such as the components of dielectric function,refractive index and other parameters of the optical properties are performed in the energy range of 0-20 eV.For HoMg,the main peak of absorption spectra and energy loss function is located at 7.44 eV and 11.76 eV,respectively.Thermal parameters such as Gruneisen parameter,Debye temperature,Specific heat etc.have been reported as a function of pressure and temperature.©2018 Published by Elsevier B.V.on behalf of Chongqing University.

Ab-initio investigation of AGeO_3(A=Ca, Sr) compounds via Tran Blaha-modified Becke Johnson exchange potential

We employ ab-initio calculations to analyze the mechanical, electronic, optical and also thermoelectric properties associated with AGeO3（A = Ca, Sr） compounds. The full-potential linearized augmented plane wave（FP-LAPW） technique in the generalized gradient approximation（GGA-PBEsol） and the lately designed Tran-Blaha-modified Becke-Johnson exchange potential are utilized to examine the mechanical and optoelectronic properties respectively. To explore the thermoelectric quality, we use the semi-classical Boltzmann transport theory. The particular structural stabilities regarding AGeO3（A = Ca, Sr） materials are validated simply by computations from the elastic constants. The energy band structural framework and the density of states are displayed to indicate indirect bandgap under ambient conditions. The particular computed optical attributes that reveal prospective optoelectronic applications are usually elucidated simply by studying ε1（0） and also Eg, which can be connected by means of Penn＇s design. The optical details uncover the actual suitability to power ranging products. Finally, the Boltz Tra P code is executed to analyze the actual thermoelectric properties, which usually presents that the increase of internal temperatures can enhance the electric conductivity, thermal conductivity and also the power factor, whilst Seebeck coefficient decreases. Therefore, the studied materials will also be ideal for thermoelectric products to understand helpful option for alternative energy resources.

Characteristics of carbonaceous aerosols analyzed using a multiwavelength thermal/optical carbon analyzer: A case study in Lanzhou City

Characteristics of atmospheric carbonaceous aerosols in Lanzhou City from December 2014 to November 2015 are analyzed using a multiwavelength thermal/optical carbon analyzer. Results reveal that average concentrations of black carbon (BC) and organic carbon in atmospheric aerosols at Lanzhou are 6.7 and 25.4 μg m^(-3), respectively, showing obvious seasonality (higher in winter and lower in summer). This is consistent with findings in cities of northern China. Primary organic aerosols and secondary organic aerosols respectively account for approximately 60% and 17% of carbonaceous aerosols. No significant seasonality is found for secondary organic carbon, indicating that its potential sources do not vary significantly throughout the study period. The mass absorption cross-section (MAC_(632nm)) of BC is 7.1 m^2g^(-1), slightly higher than that of immediately emitted BC. MAC values of BC at different wavelengths vary drastically; they are higher for ultraviolet and visible light (8.5–10.2 m^2g^(-1)) than for near-infrared light (4.9–5.7 m^2g^(-1)). The aerosol absorption optical depth generally declines from the near-infrared to the near-ultraviolet region. The values are higher in winter than in summer, thus showing there are different contributions of BC deposition in different seasons. Brown carbon (BrC) has an ?ngstr?m absorption exponent (AAE) value of approximately 2.75, which is similar to the AAE value of BrC generated by diesel combustion (2.3). The contribution of BrC to light absorption is as much as 34% at a wavelength of 635 nm. This study demonstrates that the multiwavelength thermal/optical carbon analyzer can quantify absorption properties of BrC in atmospheric aerosols. This can enhance understanding of carbonaceous aerosols and provide key parameters for simulations of climate models.

Synthesis,structural study,thermal,optical properties and characterization of the new compound[C6H7N2O2]3TeCl5·2Cl

The new organic-inorganic compound, [C_6H_7N_2O_2]_3TeCl_5·2Cl was synthesized and its structure was determined at room temperature in the triclinic system （P^-1） with the following parameters： a = 10.5330（11） ？, b = 10.6663（11） ？, c = 15.9751（16）？, α = 82.090（2）°, β = 71.193（2）°, γ = 68.284（2）°and Z = 2. The final cycle of refinement led to R = 0.057 and Rw = 0.149. The crystal structure was stabilized by an extensive network of N--H···Cl and non-classical C--H···Cl hydrogen bonds between the cation and the anionic group. Several thermal analysis techniques such as thermogravimetric analysis, differential scanning calorimetric analysis and evolved gas analysis were used. We used isoconversional kinetics methods to determine the kinetics parameters. We observe that the decomposition of [C_6H_7N_2O_2]_3TeCl_5·2Cl entails the formation hydrochloric acid of nitroaniline as volatiles. The infrared spectra were recorded in the4000–400 cm^（-1）frequency region. The Raman spectra were recorded in the external region of the anionic sublattice vibration 50–1500 cm^（-1）. The optical band gap was calculated from the UV-Vis absorbance spectra using classical Tauc relation which was found to be 3.12 and 3.67 eV.

Longwave infrared multispectral image sensor system using aluminum-germanium plasmonic filter arrays Noor E

A multispectral camera records image data in various wavelengths across the electromagnetic spectrum to acquire additional information that a conventional camera fails to capture.With the advent of high-resolution image sensors and color filter technologies,multispectral imagers in the visible wavelengths have become popular with increasing commercial viability in the last decade.However,multispectral imaging in longwave infrared(LWIR,8-14μm)is still an emerging area due to the limited availability of optical materials,filter technologies,and high-resolution sensors.Images from LWIR multispectral cameras can capture emission spectra of objects to extract additional information that a human eye fails to capture and thus have important applications in precision agriculture,forestry,medicine,and object identification.In this work,we experimentally demonstrate an LWIR multispectral image sensor with three wavelength bands using optical elements made of an aluminum(Al)-based plasmonic filter array sandwiched in germanium(Ge).To realize the multispectral sensor,the filter arrays are then integrated into a three-dimensional(3D)printed wheel stacked on a low-resolution monochrome thermal sensor.Our prototype device is calibrated using a blackbody and its thermal output has been enhanced with computer vision methods.By applying a state-of-theart deep learning method,we have also reconstructed multispectral images to a better spatial resolution.Scientifically,our work demonstrates a versatile spectral thermography technique for detecting target signatures in the LWIR range and other advanced spectral analyses.

Modeling and Performance Simulation of an Innovative Concept of Linear Fresnel Reflector based CSP System

Concentrating solar power technology is one of the most promising alternative energy technologies.In recent past,Linear Fresnel Reflector systems have received great attention and novel designs have been proposed keeping in view the objective to enhance its functionality and performance.For achieving the same objective,this study presents a novel concept where a conventional LFR is enclosed in a greenhouse called greenhouse-LFR.It was expected that such an enclosure can:(1)increase the incoming solar radiation,(2)further improve the overall efficiency due to simplified cleaning process and(3)reduce the capital cost for the construction of LFR support system.A complete thermal and optical analysis was presented for modeling and performance evaluation of the solar field of both conventional-LFR and novel greenhouse-LFR.Sets of non-linear equations for each system were solved using Newton-Raphson method.More detailed optical analysis was further performed for conventional-LFR considering the seasonal variations.The results concluded that the greenhouse-LFR is better than the conventional-LFR as it had higher efficiency and useful heat with lesser heat losses.For greenhouse-LFR,the maximum thermal efficiency was 73.2%whereas for conventional-LFR it was 37.2%.Also,there was an average increase of useful heat by 3 times in the month of February and 4.7 times in the month of September.SolTrace^(TM) analysis indicated significant spillage loss when a conventional-LFR was used without a secondary reflector or slight curvature of the mirrors.

Study on the impact of window shades’physical characteristics and opening modes on air conditioning energy consumption in China

This paper focused on the impact of window shades’physical characteristics and opening modes on annual air conditioning energy consumption of residential buildings in China.Three building models with different window layouts were proposed initially,and then validated by the dimensionless indicator annual energy performance(AEP)to determine the final building model adopted in this study.Harbin,Beijing,Guangzhou,Changsha and Kunming were selected to represent five different climate zones in China.The shading model has taken six physical characteristics of window shades,viz.outer emissivity,inner emissivity,solar transmittance,solar reflectance,thermal infrared transmittance,conductivity and two opening modes,viz.up&down mode as well as left&right mode,into consideration.Besides,the window shades operation schedule was summarized through 949 valid questionnaires.The annual air conditioning energy consumption was calculated via EnergyPlus software,and then the impact of the above different opening modes and parameters on energy use were investigated.The analysis results indicated that the top&bottom opening mode is better than the left&right mode when used in Harbin,and the effect of two different modes in air conditioning energy consumption in Kunming is similar.But in the other three cities,the left and right mode is preferred.Besides,the analysis results of the impact of different physical characteristics on air conditioning energy use in different climate zones could help improve the energy performance of window shades.