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Skeletal tailoring of two-dimensional π-conjugated polymer (g-C3N4) through sodium salt for solar-light driven photocatalysis
摘要： Structural modi?cation of graphitic carbon nitride (g-C3N4) by addition of sodium salt has been investigated for solar light-driven photocatalysis. The results from optical study indicates that the incorporation of sodium ions decreases band gap energy along with upward shifts of conduction and valence band. However, no substantial increment in surface area was observed, but morphological and optical studies con?rm that the structural deformation of g-C3N4 through sodium salt activates the ?n π * electronic transition, which can extend the absorption range to the red region attributing towards a reduced charge recombination, narrow band gap, and high conduction band edge. Furthermore, the photocatalytic activity of sodium doped g-C3N4 (0.6Na-g-C3N4) was examined under solar light for di?erent operational conditions in terms of phenol degradation of real tannery e?uent, and it was found that under optimum experimental conditions, i.e., 5 h solar irradiance, pH 5, H2O2 concentration 800 mg/L with a ?ow rate of 4 L/h, 0.6 Na- g-C3N4 exhibits 84.22% reduction in phenol while for g-C3N4 only 63.53% was observed.
关键词： Graphitic carbon nitride,Photocatalytic activity,Charge recombination,Solar irradiance,Band gap,Sodium salt
更新于2025-09-23 15:23:52
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Synthesis, characterization and optical property study of BCNO and BCN related nanopowder
摘要： Boron carbon oxynitride (BCNO) and BCN nanocompounds are successfully synthesized by a solid state sintering method using boric acid, urea and dextrose as the sources of B, N and C respectively under inert atmosphere. X-ray diffraction (XRD) and infrared spectroscopy (FTIR) analysis show that nanomaterials are synthesized at the high temperature range of 1350 oC. Sufficient amount of oxygen impurities are present in the sample, which is manifested in their photoluminescence spectra. Increase in temperature to 1350 oC under N2 atmosphere causes elimination of significant amount of O-species from the system. The presence of ample amount of carbon in the system results in the formation of high amount of polycrystalline h-BCN with minor amount of h-BN. However, some residual oxygen in the sample, which is detected in the FTIR study, leads to the formation of BCNO compound. These semiconductor BCNO compounds act as the potential luminescence centers for the blue-green emissions of the particles. Thus, these materials may find potential application as a phosphor material in various opto-electronic devices.
关键词： optical properties,carbon,boron carbon nitride,Boron carbon oxynitride,impurities
更新于2025-09-23 15:22:29
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Raman Spectroscopy || Graphene Nanocomposites Studied by Raman Spectroscopy
摘要： The goal of this chapter is to provide a general introduction about graphene nanocomposites studied by Raman spectroscopy. The chapter will therefore begin with a brief description of the major Raman bands of carbon allotropes. In the following chapter a concise comparison between single walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), fullerenes and graphene is exposed. The characteristic features in Raman spectra of carbon allotropes, namely the intense signals D and G are investigated. In particular, the chapter will outline the Raman spectrum of graphene and different types of graphene oxide. The last part of the chapter is devoted to graphene nanocomposites.
关键词： carbon nanotubes,graphene Raman bands,graphene oxide,polymeric nanocomposites,carbon allotropes
更新于2025-09-23 15:22:29
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Bio-inspired carbon doped graphitic carbon nitride with booming photocatalytic hydrogen evolution
摘要： In this work, kapok fiber (KF), known as a versatile biomass, has been mixed with melamine to produce carbon modified graphitic carbon nitride (CCN) by one-step pyrolysis. The bio-char ribbon edges formed after the decomposition of KF act as the substrate for the epitaxial growth of CCN. The photocatalytic activity in hydrogen (H2) generation from water splitting has been investigated. Nash Equilibrium from Game Theory has been firstly applied in the analysis of the H2 generation rates among catalysts. The bio-char ribbon edges at the thin CN layers after carbon doping from KF decomposition improve the charge separation and transfer for the surface H2 generation reaction. The CCN exhibits superior visible-light-driven photocatalytic activity and the H2 evolution rate (18.89 μmol/h) is 67.5 times higher than that of the pristine CN (0.28 μmol/h). The apparent quantum yields are calculated to be 4.1%, 1.4%, 0.66% for monochromatic light λ= 420, λ= 470 and λ= 550 nm, respectively.
关键词： kapok fiber,carbon doping,carbon nitride,Photocatalysis
更新于2025-09-23 15:22:29
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Sequential activation of methane by Ir+: An IRMPD and theoretical investigation
摘要： The sequential activation of up to 4 CH4 molecules by Ir+ is investigated through a gas-phase infrared multiple photon dissociation (IRMPD) experiment and theoretical calculations. A molecular beam apparatus was used to generate Ir+ by laser ablation and expose it to controlled amounts of CH4. Product ions were irradiated with IR light from a free electron laser over the 500–1800 cm?1 spectral range and photodissociation was monitored using a time-of-flight mass spectrometer. Experimental spectra were obtained for five distinct species: [Ir,3C,8 H]+, [Ir,3C,10 H]+, [Ir,4C,10 H]+, [Ir,4C,12 H]+, and [Ir,O,3C,12 H]+. To identify these species, B3LYP/def2-TZVPPD geometry optimizations were performed on a variety of possible structures, with computed IR spectra compared to the experimental IRMPD spectra. This has led to the following assignments: [Ir,3C,8 H]+ = IrCH2(CH3)2+, [Ir,3C,10 H]+ = HIr(CH3)3+, [Ir,4C,10 H]+ = Ir(CH3)2(C2H4)+, [Ir,4C,12 H]+ = a mixture of HIr(CH3)(C2H4)+(CH4), HIr(CH3)2(C2H5)+, Ir(CH3)4+, and (H2)Ir(CH3)2(C2H4)+, and [Ir,O,3C,12 H]+ = (H2O)HIr(CH3)3+. Notably, evidence for C C coupling is observed upon reaction with a fourth methane. Mechanisms for the formation of the observed products were also explored computationally by examining the reaction coordinate pathways for the reactions of methane with HIrCH+, IrCH2+, Ir(CH3)2+, HIrCH2(CH3)+, HIr(CH3)3+, and IrCH2(CH3)2+.
关键词： Iridium,Carbon-carbon coupling,Methane activation,Dehydrogenation,Infrared multiple photon dissociation,Reaction coordinate pathway
更新于2025-09-23 15:22:29
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Quantifying soil carbon stocks and humification through spectroscopic methods: A scoping assessment in EMBU-Kenya
摘要： A soil carbon assessment was performed comparing agricultural cropping systems with natural vegetation along a sampling transect spanning different agro-ecologies on the eastern foot slopes of Mount Kenya in Embu county, 125 km from Nairobi, Kenya. The aim was to determine differences in soil carbon stocks and carbon recalcitrance and relate these to soil textural class, altitude, climatic parameters and land use. Soils from main agricultural systems as tea, coffee and maize-based intercropping, as well as from natural vegetation cover were sampled in triplicates, in five layers from 0 to 30 cm in depth and processed for total carbon analysis. The whole soil samples were also analysed using Laser-Induced Fluorescence Spectroscopy (LIFS) to assess carbon humification. Prototype portable equipment intended for future in situ analysis was used in the lab to ascertain the structure of the most recalcitrant and stable carbon present in different agro-ecosystems. In addition, Near Infrared Spectroscopy (NIRS) was tested for the quantitative analysis of soil carbon, showing that it is a reproducible and low-cost method that provided satisfactory results under the processing conditions of the samples. Results showed wide variation in the level and quality of carbon stored in the soils, depending on soil texture, land use, elevation, climate, agricultural practices and land use history. Considering the heterogeneous nature of sampled soils and the performance of NIRS and LIFS, these results can be used as a basis for the development of fully portable systems able to provide rapid, clean and potentially cost-effective relevant information for soil management.
关键词： Agricultural cropping systems,Nitisols,Soil carbon stocks,Carbon humification,Mount Kenya,Andosols,Spectroscopy
更新于2025-09-23 15:22:29
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Physical and electrical properties of nitrogen-doped hydrogenated amorphous carbon films
摘要： Nitrogen-doped hydrogenated amorphous carbon films (a-C:H:N) have been prepared by a plasma-activated chemical vapor deposition technique (PACVD) by using a plasma beam source (PBS). The properties of the a-C:H:N films were changed by varying the total pressure, the substrate temperature (100 °C, 300 °C) and nitrogen partial pressure p(N2) by adding nitrogen to the precursor acetylene (C2H2). For the investigations, a-C:H:N films have been deposited onto glass slides and doped silicon wafers. The deposition rate decreased with increasing nitrogen content in the N2/C2H2 gas mixture and with decreasing total pressure. The elemental composition of two sample series (300 °C) has been analyzed with Elastic Recoil Detection Analysis (ERDA). The highest N content and N/C ratio was estimated to be 16 at.% and 0.25 at the highest p(N2), respectively. Microhardness measurements showed that the hardness decreased with increasing p(N2). Electrical resistance of the a-C:H:N films was measured by 4-point probe. Electrically conductive coatings have been obtained by nitrogen-doped a-C:H films at higher substrate temperature (300 °C). The electrical resistance of the a-C:H:N films also decreases with decreasing total pressure, with the lowest value being about 1 Ohm cm. The film density was determined by means of X-ray reflectometry (XRR).
关键词： PACVD,carbon nitride films,electrical conductivity,DLC,carbon films,XRR
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Intelligent and Innovative Computing Applications (ICONIC) - Mon Tresor, Plaine Magnien, Mauritius (2018.12.6-2018.12.7)] 2018 International Conference on Intelligent and Innovative Computing Applications (ICONIC) - OTA-C Filters for Biomedical Signal Processing Applications using Hybrid CMOS-CNFET Technology
摘要： Analog filters for biomedical signal processing applications deals with very slow or low frequency electrical activities of the physiological signals. This paper proposes first order, second order, fifth order elliptic low pass, second order notch and high pass OTA-C filters using hybrid CMOS-CNFET technology. Carbon Nanotube Field Effect Transistors (CNFETs) and CMOS devises can be heterogeneously integrated on a single 3-D chip to realize important signal processing building blocks such as OTA-C filters. Proposed circuits use Operational Transconductance Amplifier (OTA) as a building block for OTA-C filters. Realized filter circuits satisfy ultra-low power consumption requirement of wearable and implantable biomedical devices. The transistors used in the circuit operate in weak inversion to achieve ultra-low power consumption.
关键词： Noise Filtering,OTA-C Filters,Biomedical Signal Processing,Carbon Nanotube Field Effect Transistors
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Applied Engineering (ICAE) - Batam, Indonesia (2018.10.3-2018.10.4)] 2018 International Conference on Applied Engineering (ICAE) - An Integrated Comparative Approach to Estimating Forest Aboveground Carbon Stock Using Advanced Remote Sensing Technologies
摘要： Greenhouse gases in the atmosphere play a very important role in maintaining the temperature of the earth. Plants absorb carbon in the atmosphere in the form of CO2 which is beneficial for photosynthesis which will produce O2 into the atmosphere. By utilizing remote sensing technology and field data integration, this research aims to estimating aboveground carbon reserves in the research area. The results of this research indicate that the above ground carbon stock resulting from estimation calculations using remote sensing data and field calculations using brown allometric are 103,397 TonC / Ha with an error rate of 1,8354. This error level indicates the size of the error in the estimated value of each pixel.
关键词： Carbon Stock,Batam Island,Temperature,Remote Sensing Data,Greenhouse Gases
更新于2025-09-23 15:22:29
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Cathodoluminescent lamp for general lighting using carbon fiber field emission cathode
摘要： The prototype of cathodoluminescent bulb for general lighting with field emission cathode on the basis of carbon fiber is manufactured. The bulb comprises a high-voltage built-in AC-DC converter of the electric line voltage and a standard E27 cap. A high frequency converter is used to obtain high voltage. The anode voltage relative to the modulator is up to +20 kV; the cathode voltage is up to –4 kV; the current value is of the order of 1 mA. The voltage converter is located in the bulb cap and around the neck of the glass envelope.
关键词： cathode-ray-tube phosphor,carbon fiber,light sources,field emission cathodes,cathodoluminescence
更新于2025-09-23 15:22:29