Emission Transmission Research Articles

A Calculation Model of Carbon Emissions Based on Multi-Scenario Simulation Analysis of Electricity Consumption

In order to reach the peak of carbon emission in China by 2030 and to meet the low-carbon conversion of energy and the growing demand for electricity, this study aims to propose a more accurate and scientific method to calculate the carbon emissions of the entire power industry chain. This paper analyzes the historical actual operation data of the energy and power industry from 2000 to 2020, and originally proposes a carbon emission calculation model based on a multi-scenario simulation analysis of electricity consumption. This paper is an original study from the perspective of the whole industry chain of electricity production, transmission, and consumption. Firstly, a carbon emission model of the power system is established based on the carbon emission composition and transmission mechanism of the whole power industrial chain, which consists of calculation models for carbon emissions from overall electricity demand and carbon emissions from electricity network losses. Secondly, the concept of carbon emission coefficient is proposed, and the key parameters of the carbon emission coefficient of the power system are obtained through the econometric model. On this basis, the carbon emission coefficient is obtained by regression fitting of multiple key parameters according to historical data. Finally, electricity consumption per unit output value (ECPUOV) and per capita electricity consumption (PCEC) are used to predict electricity consumption in the next 15 years. This paper also makes a quantitative analysis of the relationship between CO2 emissions from the power system and electricity consumption. This paper takes G province, which ranks first in total energy consumption and economic aggregate in China, as an example and calculates its CO2 emissions and achievement of peak CO2 emissions by multi-scenario analysis. The case study results show that the low carbon scenario(LC) is the best route for G province to peak CO2 emissions from energy consumption. The method proposed in this paper can set an achievable goal of 2030 carbon peaking for the government and industry policymakers, and find a feasible implementation path.

Curing Kinetics Modeling of Epoxy Modified by Fully Vulcanized Elastomer Nanoparticles Using Rheometry Method

In this study, the curing kinetics of epoxy nanocomposites containing ultra-fine full-vulcanized acrylonitrile butadiene rubber nanoparticles (UFNBRP) at different concentrations of 0, 0.5, 1 and 1.5 wt.% was investigated. In addition, the effect of curing temperatures was studied based on the rheological method under isothermal conditions. The epoxy resin/UFNBRP nanocomposites were characterized via Fourier transform infrared spectroscopy (FTIR). FTIR analysis exhibited the successful preparation of epoxy resin/UFNBRP, due to the existence of the UFNBRP characteristic peaks in the final product spectrum. The morphological structure of the epoxy resin/UFNBRP nanocomposites was investigated by both field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) studies. The FESEM and TEM studies showed UFNBRP had a spherical structure and was well dispersed in epoxy resin. The chemorheological analysis showed that due to the interactions between UFNBRP and epoxy resin, by increasing UFNBRP concentration at a constant temperature (65, 70 and 75 °C), the curing rate decreases at the gel point. Furthermore, both the curing kinetics modeling and chemorheological analysis demonstrated that the incorporation of 0.5% UFNBRP in epoxy resin matrix reduces the activation energy. The curing kinetic of epoxy resin/UFNBRP nanocomposite was best fitted with the Sestak–Berggren autocatalytic model.

Dechlorination of persistent organic pollutants in petrochemical wastewater sludge through a planetary ball mill using synthesized nanocomposite

ABSTRACT Numerous tons of hazardous wastes containing persistent organic pollutants (POPs) are stored in an unsafe manner in the petrochemical industries. The planetary ball mill causes the formation of mineral Cl compounds during the degradation of polychlorinated compounds in the presence of various reagents. In addition, the planetary ball mill has been applied for the synthesis of diverse organic-inorganic hybrid nanomaterials. In the present study, Fe-metal organic framework was prepared using a planetary ball mill, and then Fe@C nanocomposite with core/shell structure was synthesised by carbonisation. X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) were utilised to study the synthesised materials. The nanocomposite was used as a reagent to degrade persistent organic pollutants in the sludge of a petrochemical wastewater treatment plant by a planetary ball mill. CaO was also used to compare the effect of nanocomposites on system performance. Ion chromatography (IC) analysis was carried out to determine chlorine mineralisation. Furthermore, Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy were applied to determine chemical bonds. The results illustrated a zero-valent iron nanoparticle in the core protected by carbon shell in a synthesised nanocomposite with a core/shell structure. Hence, nanocomposite was the most efficient additive, with 97% dechlorination efficiency in the first hour while the efficiency of the planetary ball mill in the presence of CaO was only 76% after 12 hours of milling. Furthermore, major changes occurred in the organic phases, carbon and chlorine bonds. Simultaneously, graphite and amorphous carbon were produced in the final products after milling. This indicates that aromatic structures and C-Cl bonds were broken down into inorganic compounds. Thus, this study presented a practical method of producing materials while degrading hazardous pollutants in petrochemical wastewater sludge through a planetary ball mill.

Physical and Electrochemical Properties of Graphene Decorated with ZnO Hollow Spheres for Supercapacitor Applications

Single-layer graphene-ZnO hollow sphere (SLG-ZnO(HS)) composites were successfully prepared through facile one-step solvothermal synthesis route. The morphological structures of the samples were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Hollow spheres consisting of ZnO nanoparticles with a diameter of approximately 30 nm are decorated to both sides of the SLG sheets. The electrochemical performances were tested by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance (EIS). The SLG-ZnO(HS) composite electrode synthesized at a concentration of 0.25 mM Zn precursor exhibited an enhanced specific capacitance of 34.7 F/g at a scan rate of 1 mV/s with energy and power densities of 5.39 W h/kg and 1.73 kW/kg, respectively.

A solid-state approach for the low temperature synthesis of Cr3Si hollow particles

Abstract In this paper, pure cubic chromium silicide (Cr3Si) hollow particles have been successfully synthesized through the solid-state reaction of chromium sesquioxide, silicon powder and metallic lithium in an autoclave at 600 °C for 10 h. The as-prepared samples were characterized by means of X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy, which showed that the as-prepared samples were cubic phase Cr3Si hollow particles. Furthermore, the oxidation resistance of the obtained Cr3Si sample was also investigated.

A Type of MOF-Derived Porous Carbon with Low Cost as an Efficient Catalyst for Phenol Hydroxylation

Using MOF-5 as a template, the porous carbon (MDPC-600) possessing high specific surface area was obtained after carbonization and acid washing. After MDPC-600 was loaded with Cu ions, the catalyst Cu/MDPC-600 was acquired by heat treatment under nitrogen atmosphere. The catalyst was characterized by X-ray powder diffraction (XRD), N2 physical adsorption (BET), field emission electron microscope (SEM), energy spectrum, and transmission electron microscope (TEM). The results show that the Cu/MDPC-600 catalyst prepared by using MOF-5 as the template has a very high specific surface area, and Cu is uniformly supported on the carrier. The catalytic hydrogen peroxide oxidation reaction of phenol hydroxylation was investigated and exhibits better catalytic activity and stability in the phenol hydroxylation reaction. The catalytic effect was best when the reaction temperature was 80°C, the reaction time was 2 h, and the amount of catalyst was 0.05 g. The conversion rate of phenol was 47.6%; the yield and selectivity of catechol were 37.8% and 79.4%, respectively. The activity of the catalyst changes little after three cycles of use.

Preparation of nano-crystalline tungsten powders from gaseous WO2(OH)2

The industrial production of tungsten powder is carried out by the reduction of tungsten oxide powder via hydrogen. In this process, the size of the W particles is limited to particle sizes larger than 100 nm. To get below this limit, alternative processes are needed. In the current work, the possibility of preparing W powder below 100 nm via a vapour phase reduction of volatile WO2(OH)2 by hydrogen was investigated. The process consists of two stages. In the first stag,e WO2(OH)2 is formed by reacting WO3 with water vapour at temperatures of 1000–1100 °C. In the second stage, WO2(OH)2 is reduced by hydrogen at about 1000 °C to form metallic tungsten. The influence of process parameters such as furnace temperature, humidity and gas flow on the WO2(OH)2 evaporation and formation of tungsten powder was investigated. The characterization of the resulting powders was performed by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). By optimization of the reaction conditions, powder with a metallic tungsten content of about 70 at% besides tungsten oxides was produced with metal particle sizes down to 5 nm. Further optimization should lead to a high tungsten content and a high product yield. Due to the small particle size, applications in catalysis might be possible, although an industrial realization of the process seems unrealistic at moment.

Estimation of otoacoustic emission and excitation force of bone conduction actuator by combined lumped parameter model

In sound presentation system using actuators which excite the surface of the pinna or head, both otoacoustic emission and vibration transmission inside the body contribute to the perception of the sound. The contribution of these pathways is affected by both the location of the excitation and mechanical characteristic of the actuator, leaving the optimal output level of the actuator to mask environmental sound or to present information yet to be estimated. This study, therefore, proposes a simplified model which combines an acoustic equivalent circuit of ear canal and a mechanical equivalent circuit of the tissues of the head. The model enables to estimate both otoacoustic emission component directly corresponding with the loudness for air conducted sound and the component of the transmission inside the head which requires the measurement of the loudness level individually by each excitation location. As the preliminary investigation preceding the establishment of the proposed model towards the human, these two components were calculated using the known parameter values for artificial ear and artificial mastoid. The results indicate that the stiffness of the excited soft tissue and the type of the actuator strongly affect the cutoff frequencies, resonances, and anti-resonances observed within the audible range.

A Magnetic Nanocomposite Modifier for Improved Ultrasensitive Detection of Hexavalent Chromium in Water Samples

In this work, different electrodes were employed for the determination of Cr(VI) by the cathodic square-wave voltammetry (SWV) technique and the square-wave adsorptive stripping voltammetry (SWAdSV) technique in combination with diethylenetriaminepentaacetic acid. Using SWV, a comparison of the analytical performance of the bare glassy carbon electrode (GCE), ex situ electrodes (antimony-film—SbFE, copper-film—CuFE, and bismuth-film—BiFE), and the GCE modified with a new magnetic nanocomposite (MNC) material was performed. First, the MNC material was synthesized, i.e., MNPs@SiO2@Lys, where MNPs stands for magnetic maghemite nanoparticles, coated with a thin amorphous silica (SiO2) layer, which was additionally functionalized with derived lysine (Lys). The crystal structure of the prepared MNCs was confirmed by X-ray powder diffraction (XRD), while the morphology and nano-size of the MNCs were investigated by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM), where TEM was additionally used to observe the MNP core and silica layer thickness. The presence of functional groups of the MNCs was investigated by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and surface analysis was performed by X-ray photoelectron spectroscopy (XPS). The hydrophilicity of the modified electrodes was also tested by static contact angle measurements. Then, MNPs@SiO2@Lys was applied onto the electrodes and used with the SWV and SWAdSV techniques. All electrodes tested with the SWV technique were effective for Cr(VI) trace determination. On the other hand, the SWAdSV technique was required for ultra-trace determination of Cr(VI). Using the SWAdSV technique, it was shown that a combination of ex situ BiFE with the deposited MNPs@SiO2@Lys resulted in excellent analytical performance (LOQ = 0.1 µg/L, a linear concentration range of 0.2–2.0 µg/L, significantly higher sensitivity compared to the SWV technique, an RSD representing reproducibility of 9.0%, and an average recovery of 98.5%). The applicability of the latter system was also demonstrated for the analysis of a real sample.

TCA (Ag doped TiO2-CuO) mesoporous composite nanoparticles: optical, XPS and morphological characterization

Due to the increasing importance of photocatalysts in the treatment of industrial effluents, in this study, Ag doped TiO2-CuO (TCA) composite nanoparticles were synthesized by sol–gel method. Tetra butylorthotitanate (TBT), copper (II) nitrate trihydrateas, silver nitrate was used as a precursor to titanium dioxide, copper oxide, and silver respectively. Ethanol was used as a solvent. X-ray diffraction (XRD), UV–Vis spectroscopy, nitrogen adsorption–desorption isotherm (BET-BJH), field emission scanning electron microscope (FESEM) and transmission electron microscopy (TEM) were used to characterize the nanoparticles. The synthesized photocatalytic nanoparticles have been used to degrade the methylene blue dye solution as a model of organic pollutant under UV and Visible light irradiation. The particle size of TCA-550 sample (highest percentage of photocatalytic degradation under visible light = 43.95%) was about 21–35 nm and the particle size of TCA-650 sample (highest percentage of photocatalytic degradation under UV light = 59.64%) was 39–60 nm. According to the XPS study, the element Ti was predominantly chemically present as Ti4+. Ag was found to be a cation with a capacity of one (Ag+).

Ultrasound assisted synthesis of pyrano[3,2-b]pyran and 7-tosyl-4,7-dihydropyrano[2,3-e]indole scaffolds using barium titanate nanoparticles

Barium titanate nanoparticles (BaTiO3 NPs) were synthesized under sonochemical conditions. The synthesized BaTiO3 NPs was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetry analysis (TGA), Brunauer–Emmett–Teller (BET), Field emission scanning electron microscopy (FE-SEM) and Transmission electron microscopy (TEM). Morphological study reveals that BaTiO3 NPs have spherical shape with particle size ranging between of 60 and 80 nm. BaTiO3 NPs were further utilized as an efficient and reusable heterogeneous catalyst for ultrasound assisted synthesis of pyrano[3,2-b]pyran. In addition, novel 7-tosyl-4,7-dihydropyrano[2,3-e]indole derivatives were also synthesized using ultrasonication. This new catalytic method displays several notable features such as simplicity, short reaction time, easy work up, easy purification, increased yield and green reaction conditions. The nanocatalyst was reusable up to five runs with marginal loss in its catalytic activity.

A Novel Ceramic Sensing Material for Acetone Detection from Asphalt

A novel ceramic sensing material, orthorhombic molybdenum trioxide (a-MoO3) nanobelts, was successfully prepared through a simple hydrothermal strategy. And its crystalline phase and microstructures were characterized via X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). The results indicate that the size of the a-MoO3 nanobeltsis 180-250 nm in width and several microns in length. Gas sensing performances of the as-synthesized a-MoO3 nanobelts towards acetone vapor which was a representative VOCs in asphalt were investigated. The a-MoO3 nanobelts based gas sensor exhibits superior response at the optimum operating temperature of 300 °C for 200 ppm acetone vapor and excellent stability. The gas sensing mechanism for the a-MoO3 nanobelts to acetone vapor was also discussed.

Studying the Regional Transmission and Inferring the Local/External Contribution of Fine Particulate Matter Based on Multi-Source Observation: A Case Study in the East of North China Plain

The regional transmission characteristics as well as the local emission and external transmission contribution of fine particulate matter in the eastern North China Plain were investigated using multisource data. Himawari-8 aerosol optical depth can represent the whole layer of air pollution situation; hourly aerosol optical depth were used to reconstruct the route of fine particulate matter horizontal transmission, and the transmission speed was calculated and compared with the near-surface wind speed. A case study conducted on 22 September 2019 showed the pollutant was mainly transmitted from Tangshan to Dezhou, and the transmission speed was greater than the near-surface wind speed. We also found that pollution air mass had 2–3 h of diffusion delay in the near-surface pollutant monitoring results. In addition, the vertical diffusion of pollution mainly occurred at low altitude below 1.8 km. The contribution of local emission and external transmission was inferred in this study with the help of the WRF-Chem model, the pollution in the northeastern portion of the study area mainly derived from local emissions, while the southwestern portion of the study area was mainly affected by external transport. Among them, the local emission accounted for 79.15% of the pollution in Tangshan, while the external transmission contributed 60.28% of the fine particulate matter concentration in Dezhou.

Quantitative analysis of phosphorus and sulfur in vegetation samples at minor and trace levels by EDXRF technique

In this paper, a rapid, simple and reliable quantitative analysis method for Phosphorus and Sulfur in milligram quantities of plant samples by EDXRF has been described. The method uses a thin film sample preparation procedure which includes drying, suspension samples, filtration and pressing of the thin film samples. By measuring four random points of the same thin film sample, the homogenization of thin layer samples was evaluated to ensure the stability of the quantitative analysis results. The calibration curves of P, S, Ca and Fe was established by changing the weight of certified reference materials (CRMs) deposited on the filter. Then, the emission-transmission (E-T) method was used for correcting the matrix absorption effects of phosphorus and sulfur in the thin layer samples. After the correction, the correlation coefficients (R2) of the calibration curves of P and S were higher than 0.99. To evaluate the accuracy of quantitative analysis method, three vegetation verification samples were synthesized by adding the analytical pure powder to CRMs. The quantitative analytical results of EDXRF and ICP-OES were compared to the synthesized value. For P and S elements, the relative error of EDXRF and ICP-OES were 1.2%–6.4% and 4.2 %to 11.4%, respectively.

Highly efficient sers performance from the silver nanoparticles/graphene nanoribbons/ cellulose paper

Introduction: Metal/graphene heterojunction structure has been one of the most crucial tools in the growth of high-performance Surface-enhanced Raman spectroscopy (SERS) platform, which is appropriate for sensing applications. In this research, we developed a SERS platform, graphene nanoribbons (GNRs) decorated silver nanoparticles (AgNPs) on cellulose paper substrate, in which GNRs was synthesized by wet chemical based on unzipping process of Multi-walled carbon nanotubes (MWCNTs), then GNRs hybridized with AgNPs through magnetron sputtering method.
 Methods: The morphology of graphene nanoribbons coated-Ag (AgNPs@GNRs) was analyzed by field emission scanning electronic microscopy (FESEM) and transmission electron microscopy (TEM). The quality and thermal stability of GNRs were characterized using thermogravimetric analysis. Besides, its structure and quality were also characterized by Raman spectroscope.
 Results: The results show that the unzipping process of MWCNTs to form GNRs was strongly affected by dispersing time and stirring temperature. The suitable condition creating the Graphene Nanoribbons using MWCNTs was the dispersing time of 10 mins in an acid environment, stirring in 30 mins at room temperature and in 45 min at 100°C. Moreover, SERS platform of AgNPs@GNRs exhibit the outstanding SERS signal enhancement with rhodamine 6G (R6G) low concentration of 10-5 M compared with pristine graphene and silver thin film. This could be attributed to the synergistic effect between AgNPs, GNRs and analyze molecules based on the enhancement of electromagnetic mechanism (EM) and chemical mechanism (CM), which plays a vital role in promoting the improvement SERS behavior.
 Conclusion: Ag NPs assembled onto graphene nanoribbons/ cellulose paper substrate could also serve as SERS active substrates for practical applications in various fields at trace levels.

Bimetallic Mo–Fe Co-Catalyst-Based Nano-Carbon Impregnated on PAC for Optimum Super-Hydrophobicity

The application of super-hydrophobic nanomaterials for synthesizing membranes with unique physiochemical properties has gained a lot of interest among researchers. The presence of super-hydrophobic materials inside the membrane matrix can play a vital role not only in the separation of toxins, but also to achieve higher water flux with lower fouling tendencies required for an efficient membrane distillation process. In this research, super-hydrophobic carbon nanomaterials (CNMs) were synthesized using powder activated carbon (PAC) as a precursor, whereby the growth was initiated using a bimetallic catalyst of iron (Fe) and molybdenum (Mo). Until recently, no research has been conducted for synthesis and to observe the catalytic influence of bimetallic catalysts on the physiochemical characteristics of the derived CNMs. The synthesis process was carried out using the chemical vapor deposition (CVD) process. The CVD process was optimized using Box–Behnken factorial design (BBD), whereby 15 experiments were carried out under different conditions. Three input variables, which were percentage composition of catalysts (percentage of Fe and Mo) and reaction time (tr), were optimized with respect to their impact on the desired percentage output of yield (CY) and contact angle (CA). Analysis of variance (ANOVA) testing was carried out. It was observed that the developed model was statistically significant. The highest CY (320%) and CA (172°) were obtained at the optimal loading of 5% Fe and 2% Mo, with a reaction time of 40 min. Surface morphological features were observed using field emission scanning electron microscopic (FESEM) and transmission electron microscopic (TEM) analysis. The images obtained from FESEM and TEM revealed the presence of two types of CNMs, including carbon nanofibers (CNFs) and multiwall carbon nanotubes (CNTs). Thermogravimetric analysis was carried out to observe the temperature degradation profile of the synthesized sample. Raman spectroscopic analysis was also used in order to have a better understanding regarding the proportion of ordered and disordered carbon content inside the synthesized sample.

Silver nanoparticles-assembled graphene oxide sheets on TiO2 nanotubes: synthesis, characterization, and photocatalytic investigation

In this study, graphene oxide (GO) sheets were assembled with silver nanoparticles (AgNPs) and then combined with TiO2 nanotubes (TNTs) by γ-ray irradiation at different doses (5, 10, 15, 20, and 25 kGy), to form GO–AgNPs–TNTs nanocomposites. Their physical and chemical properties were investigated using Fourier-transformed infrared, ultraviolet–visible (UV–Vis) adsorption, Raman and X-ray diffraction (XRD) spectroscopies. Field emission scanning electron and transmission electron (TEM) microscopies were applied for their morphology and structure observation. The obtained results indicated successful assemblage of silver nanoparticles on both GO sheets and TNTs, as well as significant effects of irradiation dose on nanocomposites’ characteristics. Photocatalytic activity of the material was determined by the photodegradation efficiency on rhodamine B dye solution. All nanocomposite samples were revealed to possess good photocatalytic activity, with the highest obtained decoloration efficiency value of 81.21%. Noticeably, the photocatalytic activity of all nanocomposite samples was higher than that of their sole components. With all obtained results, γ-ray irradiation was demonstrated to be a good technique for the synthesis of nanocomposite materials and GO–AgNPs–TNTs nanocomposite proclaimed high potential for pollutants removal and wastewater purification.

Materials Characterization of Cobalt Antimonide Nanostructures as Thermoelectric Material

Cobalt antimonide (CoSb3) nanoparticles, a binary skutterudite structure, are synthesized by following solvothermal method using water as solvent. The solvothermally processed powders are annealed to remove the excess Sb to achieve single phase CoSb3 nanoparticles, and are examined by X-ray diffraction (XRD) indicating the formation of cubic phase of CoSb3. The structural analysis by selected area electron diffraction (SAED) and the elemental composition of 1:3 for Co and Sb using energy dispersive X-ray spectrophotometer (EDX) predicts formation of high purity crystalline CoSb3 nanoparticles. Morphology of the annealed CoSb3 powders observed using field emission scanning electron microscope (FESEM) and transmission electron microscopy (TEM) indicates particle size of 50-100 nm. The ultraviolet–visible (UV-Vis) absorption spectroscopy estimates an energy gap of 3 eV. The nanosized CoSb3 skutterudites are potential intermediate-temperature thermoelectric materials with further application in developing efficient thermoelectric modules.

Preparation of thermal infrared and microwave absorber using WO3/MnFe3O4/polyaniline nanocomposites

ABSTRACT In this study tungsten trioxide has been synthesised as a thermal infrared (TIR) absorbent by sol–gel method and characterised by X-ray diffraction (XRD), field emission scanning electron microscopes (FESEM) and transmission electron microscopy (TEM). XRD analysis shows that the single phase and hexagonal tungstate was prepared. The crystallite size measured by Scherer formula is in good accordance with the crystallite nano size measured by TEM. The polyaniline (PANI) was coated on WO3/MnFe2O3 nanoparticles (NPs, 50/50 wt%) via in situ polymerisation by core-shell structure WO3/MnFe2O3/PANI nanocomposite (50% wt as core). Structural and morphological characteristics of the produced nanocomposite were studied via X-ray diffraction, Fourier transformation infrared spectroscopy and scanning electron microscopy. The electric property was also performed by four probe method. The results showed that the WO3/MnFe2O3/PANI nanocomposites have good electric property. The TIR absorption of nanocomposite was investigated at 10–40 µm frequencies. The TIR images testing showed that the ability of infrared thermal imaging was increased by increasing WO3/MnFe2O3 as core and independent to increasing PANI as final shell. The test microwave absorption properties of the nanoparticles powder dispersing in PANI and thickness of 1.5 mm were investigated by using a vector network analysers in the frequency range of 8–12 GHz. A minimum reflection loss of the nanocomposite reaches -12 dB were observed at 8.8 and 11.6 GHz, respectively.

One-Step Route to Grow ZnO Hexangular Tube Structures

We present a systematic study of hexangular ZnO nanotube growth using zinc nitrate and NaOH as starting materials by varying solution concentration. ZnO nanotubes were characterized by field emission scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and growth mechanism was discussed. Supersaturation near ZnO surface is higher and leads to the [Formula: see text]-axis preferential growth. Low-magnification and high-resolution TEM micrographs revealed that best growth conditions for ZnO nanotube arrays were at 5[Formula: see text]mM zinc nitrate and 1[Formula: see text]mL of 1[Formula: see text]M NaOH. The growth morphology is largely determined by varying the NaOH concentration.