Intensity Of Main Peak Research Articles

Research on Jamming to RF Screening Radar Based on Signal Reconstruction

Aiming at the problem that the jamming effect to RF screening radar by active jammer is not satisfactory, this paper provides one jamming method based on signal reconstruction. That jamming method conducts signal reconstruction based on estimation to radar signal parameters, which can achieve effective jamming to RF screening radar. The method at first, establishes jamming theory model based on signal reconstruction, and conducts simulation research accordingly. This paper makes simulation to that method. The results indicate that the relative intensity of main peak after pulse compression decreases with increase of frequency deviation or relative FM slope deviation, the decrease distribution caused by positive/negative deviation is symmetric, if frequency or FM slope of reconstructed jamming signal is closer to radar signal, the gain is higher after pulse compression. So overall consideration should be conducted during jamming design to select proper frequency deviation and FM slope according to jamming power. The method provided in this paper has important reference value for engineering research.

Structural, optical and photocatalytic properties of pure and Pd-doped CdS thin films

Pure and palladium (Pd)-doped cadmium sulfide (CdS) thin films were deposited on glass substrate by successive ionic layer adsorption and reaction (SILAR) process with different doping concentrations. X-ray diffraction results confirmed the crystalline and hexagonal phase structure of prepared samples. The increase in the main diffraction peak (002) intensity with increasing Pd concentration revealed the substitution of Pd+2 with Cd+2 in the lattice. The crystallite size increased from 58.32 to 89.71 nm with Pd concentration. Morphology of the thin films shown that the average grain size increases by the agglomeration of nano-grains which become cluster of particles after Pd+2 incorporation. The energy bandgap of the CdS thin films is decreased from 2.44 to 2.37 eV with increasing Pd percentage. Photoluminescence (PL) spectra described that the pure and Pd-doped thin films show a broad PL emission peak associated to the transition of sulfur ion vacancy transfers to the valence band. Moreover, the Pd doping improved the film photostability as well as the photocatalytic degradation of methylene blue (MB).

Structural, morphological, optical analyses of Ni-doped CdS thin films and their photovoltaic performance in hybrid solar cells

This work reports influences of variation in Ni-doping on structural, morphological, and optical properties of CdS thin films and in their hybrid solar cell applications. X-ray diffraction data showed that increase of Ni-doping in CdS structure caused not only a broadening in CdS peak but also a decrease in the intensity of main cubic CdS peak. Morphological studies illustrated that lower amount of Ni-doping treatment firstly reduced the grain size of CdS thin films, whereas higher concentration of Ni-doping led to bigger grains. The best transparent CdS sample was achieved for 1 at% Ni-doping as 95% at 675 nm. Compared with CdS thin films (2.98 eV), bandwidths of Ni-doped CdS samples gradually increased and reached to 3.39 eV, which is due to the existence of strong quantum confinement effect. Photoluminescence (PL) data of the device demonstrated that the most efficient electron transfer was accomplished at CdS/P3HT interface for 1 at% Ni-doping because this device demonstrated the lowest PL peak intensity. Current density–voltage (J–V) characteristics of CdS-based device exhibited a power conversion efficiency (PCE) of 0.296% and it enhanced to 0.663% for device including 1 at% Ni atoms, which is most probably due to achievement of most efficient exciton dissociation between CdS and P3HT layers as approved by PL results. However, with increasing Ni-doping amount up to 3 at% and 5 at%, PCE values were in turn obtained as 0.131% and 0.208%, indicating a deterioration in PCE value of cells, which might be due to the less efficient exciton dissociation at the interface. Further increase of Ni-doping to 7 at% led to an efficiency value of 0.417%, which is still lower than that of 1 at% Ni-doped CdS-based device.

Crystal polymorphism of polylactide and its composites by X-ray diffraction study

Polylactide (PLA) exhibits various types of crystal modifications depending on the preparation conditions, including the components. To solve the open question, a reliable calculation method for crystallinity, crystal forms, and composition in neat PLA and PLA composites was developed on the basis of temperature-dependent synchrotron wide-angle X-ray diffraction results. The relative composition of amorphous, α-form, and α’-form phases of PLA and its composites filled with halloysite nanotubes during heating was successfully obtained. It was found that only 47–56% of α’-form crystals transform into α-form crystals during a 2 °C/min heating process for PLA with a molecular weight of 54,300 g/mol. The loading of halloysite nanotubes decreases the cold crystallization and starting transition (α’ crystals transform into α-form crystals) temperatures of PLA. The crystallinity and the main diffraction peak intensity as a function of temperature were also analyzed. These results suggest that the α’-to-α form transition is a solid-solid phase transition. Polylactide (PLA) exhibits various types of crystal modifications depending on the preparation conditions, including the components. To solve the open question, a reliable calculation method for crystallinity, crystal forms and composition in neat PLA and PLA composites was developed on the basis of temperature-dependent synchrotron wide-angle X-ray diffraction results. The relative composition of amorphous, α-form, and α’-form phases of PLA and its composites filled with halloysite nanotubes during heating was successfully obtained.

Performance Evaluation of Single-Junction Indoor Photovoltaic Devices for Different Absorber Bandgaps Under Spectrally Varying White Light-Emitting Diodes

In this article, we present a detailed theoretical study to predict performance characteristics of single-junction indoor photovoltaic (PV) devices operated under white light emitting diodes (LEDs) having different spectral characteristics. Efficiency limits of both ideal and practical PV converters have been evaluated considering illumination by commercially available white LEDs. The obtained results have been generalized for white LED sources having a wide range of correlated color temperatures (CCTs) and fraction of blue in their corresponding spectrum. Depending on bandgap of the absorber material, both positive and negative correlations are observed between photon conversion efficiency of PV devices and CCT values of the white LED sources. For material bandgaps of ∼1.5 eV or lower, higher photon conversion efficiencies are obtained for warm glow white LEDs. On the contrary, white LEDs characterized to emit cool light are found to be more conducive for PV devices having absorber layer bandgaps of ∼2 eV or higher. The observed characteristics have been explained in terms of linewidth of the main emission peak and relative intensity of blue emission peak of the irradiating white LED spectrum. Based on the analysis of photon yield, three distinct bandgap ranges of the PV absorber material have also been identified, each of which represents different dependence of PV device performances on the white LED spectral characteristics. These results in effect provide the necessary guidelines for designing homojunction, heterojunction, or tandem PV devices suitable for operation under different practical white LED sources.

Study the influence of Solvothermal Conditions Changing On UiO-66

Metal Organic framework UiO-66 considered to have significant physicochemical characteristics with great potential for various applications. Nevertheless obtaining high porous prosperities by optimization the synthesizing method remained challenge. In this study, a solvothermal method has been used to synthesis the UiO-66 with different synthesis time (12, 24, 48, 72 and 96 hours) and different heated (80, 100, 120, and 140 °C). By changing the temperature up to 140 and synthesis time 24 h the main peak intensity increased. The XRD and SEM analysis showed that by increasing the synthesis temperature the degree of crystallinity increased and cubic shape crystals was obtained. The XRD characterization analysis for UiO-66 showed the white powdered obtained at 12 h reaction time and 140 °C synthesis temperatures was the highest XRD intensity at 7.3°, 8.4°, 25.6° and 30.6° 2Theta. When changing the synthesis time for 48 h or longer, XRD diffractograms revealed phase change and that the intensity at 7.3° 2Theta was lower than the intensity at 8.5° 2Theta, with new peaks appeared. SEM analysis confirmed the phase change after synthesis time 48h, by changing the crystals square clusters shape to the needle-like shape.

Study of pre-formulation and development of solid lipid nanoparticles containing perillyl alcohol

The aim of this work was to study the physicochemical characterization of lipid matrices composed of cetyl palmitate (CP)/perillyl alcohol (PA) and develop preliminary studies of SLN for potential application in cancer treatment. The pre-formulation was submitted to recrystallization process (heating–cooling) in a concentration of CP/AP (F1 1:0; F2 1:9; F3 1:3; and F4 1:1). The characterization showed TG presents a single stage of thermal decomposition for AP, F1, F2 and F3 and two stages for F4. DSC decrease of the onset temperature of CP before and after thermal decomposition in all samples indicates a reduction in crystallinity, and WAXD data confirmed DSC results, showing a reduction in the intensity of main diffraction peaks of the lipid mixtures and a presence of the amorphous portion in 2θ angles of 21.51° and 23.62°. Results showed the binary mixtures presented a amorphous portion facilitates AP incorporation in SLN satisfactory size, polydispersity index, zeta potential and morphology was obtained.

Impact of Differently Prepared Paper Production Waste Sludge (PSw) on Cement Hydration and Physical-Mechanical Properties

After analysis of calorimetric tests results of the cement mixtures with PSw prepared at different temperatures and SEM, XRD, physical-mechanical properties results of cement stone hardened for 7 and 28 days, it is determined that PSw can be utilized/used for the preparation of cement mixtures by adding up to 5%. Depending on the environmental working conditions, the preparation of PSw can be selected. To slow down cement hydration processes, it is useful to use only dried PSw, which slows down the hydration of the cement due to the high content of cellulose contained in PSw. To accelerate cement hydration, it is expedient to use PSw which is burned at 700°C. Dried PSw performs an extended induction hydration period and significantly delays the second heat release time. After the addition of 5% dried PSw, the phase III effect time compared to the control sample is 1.8 h, and after 10% addition, it is extended to 4.4 h. After the addition of 5% burnt PSw, the phase III effect time compared to the control sample is hastened to 1.9 h, after inserting 10% – to 2.4 h. The use of PSw saves the environment, reduces the amount of cement in the mixture and improves the properties of cement materials. Using 5% PSw burned at 700°C instead of cement increases the compressive strength of the specimens, and the density as well as ultrasound pulse velocity values are slightly changed compared to the control sample. It is determined that burnt PSw significantly changes mineral composition and structure. It is found that the microstructure of samples without PSw and samples with dried 5% PSw is similar, crystals formed are visible. With a higher (10%) amount of dried PSw, the microstructure of the cement stone differs significantly from the control samples. Larger voids with plenty of etringite are also visible, as well as higher levels of calcite. The microstructure of specimens with burnt PSw is significantly denser. XRD studies show that with a higher amount of PSw burned at 75°C, the main peak intensities of crystallohydrates ettringite and portlandite are lower, while the peak intensities of calcite are higher compared to samples without PSw. By increasing the amount of dried PSw in mixtures and reducing the amount of cement, the peak intensities corresponding to CSH and CASH are lower compared to those of the control samples. Using burnt PSw also reduces the peak intensities of ettringite, portlandite, CSH and belite, but significantly increases peak intensities of calcite and CASH.

Investigation of the structural, magnetic and electrical properties of the Au doped YBCO superconductors

In this study, a systematic investigation of Au-added YBa2Cu3O7−x (YBCO) samples has been undertaken mainly to understand their structural, magnetic as well as electrical behavior. In order to get high quality of superconducting bulk samples, optimum preparation conditions have been provided. The bulk samples were produced by conventional solid state reaction method at 930 °C under the low oxygen atmosphere. The bulk samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), electron dispersive X-ray, dc electrical resistivity (ρ-T), critical current density and ac magnetic susceptibility measurements. The samples were carried out by means of powder X-ray diffraction for phase analyses, and lattice parameters, SEM for microstructure examinations. From XRD and SEM results, an increase in the intensity of main peaks and average grain size but a increase in the lattice parameter c with addition of Au in comparison with the unadded sample. In addition to this, onset-offset critical transition temperature ( $${T}_{c}^{on}, {T}_{c}^{off}$$ ) was determined from dc electrical resistivity ( $$\rho -T$$ ) as a function of temperature measurements. Moreover, the transition temperature (Tc) and the critical current density (Jc) are enhanced upon Au addition when compared with unadded YBCO superconductor sample. The increment of Au content decreased the transition temperature and the critical current density values. From the AC susceptibility measurements, inter-grain, intra-grain peak temperature and superconducting transition temperature were determined. The possible reasons for the observed improvements in structural, magnetic and electrical properties due to the Au addition in the YBCO samples were discussed by comparison with other studies about addition of transition metals in high temperature superconductors.

Thermal dehydrogenation of n-alkane on Au(111) and Pt(111) surface

Thermal dehydrogenation of long n-alkane on Au(111) and Pt(111) surfaces is investigated by near the carbon K-edge X-ray absorption fine structure spectroscopy (C K-NEXAFS) and scanning tunneling microscopy (STM) under ultrahigh vacuum (UHV). On Au(111), dehydrogenation and formation of unsaturated bonds start at temperatures above 480 K, ending at 650 K. This is confirmed by the decrease in the 1 s → σ*CH/R resonance (σ*CH/R resonance) and the evolution of the π*CC resonance in the C K-NEXAFS spectra. The aliphatic or non-aromatic unsaturated bonds are generated at the early stage of the dehydrogenation on the Au(111), which is examined by the reaction with bromine. The dual peaks of the π*CC resonance at 284–286 eV suggest the formation of polycyclic aromatic hydrocarbons (PAHs). These PAHs exhibit a ribbon or rosary and planer shape by heating at 800 K, which is observed by the STM. In contrast, dehydrogenation begins at RT on Pt(111), and is almost completed at 480 K. π*CC resonance exhibits a main peak at 286 eV, which corresponds to a graphene skeleton, with a sub peak or a shoulder at 284.6 eV, which is attributed to a carbon atom at an edge or defect. The main peak intensity increases as the temperature is raised up to 820 K. STM images obtained after heating at 820 K show nanodots having a diameter of ca. 2–3 nm. The final products upon heating to 1000 K on Pt(111) are graphene nanoflakes with a size of tens of nanometers. The difference between the products is related to the difference between the reaction pathways on Au(111) and Pt(111) surfaces.

Fluorescence spectrum photo-bleaching analysis for distinguishing microorganisms (bacteria and fungi) from other particles in air.

A new device with a 405 nm blue laser diode is developed for collecting samples in air and detecting their spectra variation. The multi-sample particles which are pure microorganisms can be distinguished from interferents in the air by photo-bleaching phenomenon. Six types of microorganisms and twelve types of interferents from the air, which exhibit laser-induced fluorescence, are used to evaluate the performance of the analysis approach, and their fluorescence emission spectra are presented. The results show that when microorganisms are illuminated by the laser, the fluorescence spectra will change significantly within several minutes, including both the wavelength of the main peak and fluorescence intensity. Our work provides a potential approach to distinguish microorganisms from other particles by the changes.

The Draconid Meteoroid Stream 2018: Prospects for Satellite Impact Detection

Abstract Predictions of the 2018 Draconid activity at the Earth and the Sun–Earth L1 and L2 Lagrange points are presented. Numerical simulations of the meteoroids’ ejection and evolution from comet 21P/Giacobini–Zinner are performed with a careful implementation of the results analysis and weighting. Model meteoroid fluxes at Earth are derived using as calibration the main peak date, intensity, and shower profiles of previous Draconid outbursts. Good agreement between the model and measurements is found for the 1933, 1946, 1998, and 2011 showers for a meteoroid size distribution index at ejection of about 2.6. A less accurate estimate of the peak time for the 1985, 2005, and 2012 predominantly radio-observed outbursts was found by considering the contribution of individual ejection epochs, while the model peak flux estimate was found to agree with observations to within a factor of 3. Despite the promising geometrical configuration in 2018, our simulations predict low Draconid activity is expected on Earth, with a maximum of less than a few tens of meteors per hour around midnight of 2018 October 9, confirming previous models. At the L1 and L2 Lagrange points, however, the flux estimates suggest a “meteoroid storm.” The Gaia spacecraft at the L2 region might be able to detect small (≈μg) Draconid meteoroid impacts centered in a two-hour window around 18h30m UT on the 2018 October 8.

Sr substitution effects on atomic and local electronic structure of Ca2AlMnO5+δ

We performed the first‐principle calculations based on spin‐polarized density functional theory to investigate the Sr substitution effects on the atomic and local electronic structure of Ca2AlMnO5+δ. The ionic radius of Sr2+ is larger than that of Ca2+; thus, the lattice expansion occurs with Sr substitution. From the total energy calculations, we found that Sr substitution makes the oxygen‐absorbed phase unstable and realizes the lower operation temperature. From the point of atomic structure, Sr substitution lengthens the bond length between Mn and O atoms connecting Mn and Al atoms in Al tetrahedral (OMn‐Alt) in oxygen‐absorbed phase, because the large Sr2+ prevents the release of the Jahn‐Teller distortion. We also found that the covalent bonding between Mn and OMn‐Alt atoms weaken with Sr substitution by the local electronic structure analysis, which results in the unstable oxygen‐absorbed phase and weak prepeak and main peak intensity near the onset of O‐K edge ELNES of OMn‐Alt atoms.

Determination of crystallization threshold temperature for sol-gel spin coated Cu2ZnSnS4 thin films

The effects of annealing temperature and time on sol-gel Cu2ZnSnS4 thin film spin coated on soda lime glass substrate were investigated in terms of crystallinity, morphology, composition, optical and electrical properties. The annealing process was achieved in a tube furnace under N2 gas flow and S vapor. The importance of this work is the detailed investigation of annealing temperature and its effect on the Cu2ZnSnS4 thin films that were prepared by the sol-gel spin coating method. The threshold temperature where the film begins to crystallize has been determined to be 465 °C. A temperature increase of 15 °C from 450 to 465 °C boosted the crystallite size and main peak intensities and optimized energy gap from 1.38 to 1.46 eV. In summary, the effect of the annealing temperature on the crystallinity of the films was studied in detail and the threshold temperature value which improved the crystallinity was determined.

Synthesis and enhancement of photoluminescent properties in spherical shaped Sm3+/Eu3+ co-doped NaCaPO4 phosphor particles for w-LEDs

A series of Sm3+ doped and Sm3+/Eu3+ co-doped NaCaPO4 phosphors have been successfully synthesized via molten salt method. The structural, morphological, optical, photoluminescence and decay properties of the synthesized phosphors were investigated. Sm3+ doped phosphor exhibits excellent emission properties in the orangish-red region under n-UV excitation (403 nm), and the optimized doping concentration of Sm3+ was found to be 1.0 mol%. The excitation spectrum confirms that Sm3+/Eu3+ co-doped NaCaPO4 phosphors can be efficiently excited by both n-UV and blue LED chips. In the co-doped NaCaPO4:Sm3+/Eu3+ phosphors, the intensity of main characteristic emission peaks of Sm3+ decreased and Eu3+ increased with increasing Eu3+ ion concentration. The energy transfer (ET) from Sm3+ to Eu3+ was demonstrated to be quadrupole-quadrupole in nature by applying Dexter's ET formula and Reisfeld's approximation. Commission Internationale de l′Eclairage (CIE) chromaticity coordinates for co-doped samples lie in the red region. The decay time for the 4G5/2 level of Sm3+ decreases with increasing Eu3+ concentration, which also indicate the energy transfer from Sm3+ to Eu3+. These results indicate that Sm3+/ Eu3+ co-doped NaCaPO4 multifunctional phosphor is a promising and an attractive potential candidate for n-UV and blue excitation based w-LEDs.

Electronic Structure of Boron Doped HOPG: Selective Observation of Carbon and Trace Dope Boron by Means of X-ray Emission and Absorption Spectroscopy

We have measured the soft X-ray absorption and emission spectra of near B-K and C-K absorption edges of highly oriented pyrolytic graphite (HOPG) doped with a small amount (0.32 at.%) of boron (B), including incident/takeoff angle dependence.The main peak intensities at the B-K edge around 182 eV were almost independent on the change of takeoff angle. On the other hand, the satellite peak around 185 eV becomes larger as the takeoff angle becomes smaller. Based on this result, unlike the previous assignment of the main peak predicted from the quantum chemical calculation (π orbitals), it is reasonable to attribute the main peak to the σ orbitals. The takeoff angle dependence of the B-K emission is similar to the angle dependency of the C-K emission of undoped HOPG. Based on this and the theoretical consideration, it is presumable that the doped B atom does not intercalate between the layers of HOPG; it replaces the C atom of the hexagonal network structure and has a wave function similar to that of C atoms (sp2 type hybridized orbital). (Less)

In situ SR-XRD study of FeCO3 precipitation kinetics onto carbon steel in CO2-containing environments: The influence of brine pH

The growth of iron carbonate (FeCO3) on the internal walls of carbon steel pipelines used for oil and gas transportation can reduce internal corrosion significantly. Solution pH can be considered as one of the most influential factors with regards to the kinetics, morphology and protection afforded by FeCO3 films. This paper presents results from a recently developed in situ Synchrotron Radiation-X-ray Diffraction (SR-XRD) flow cell integrated with electrochemistry for corrosion measurements. The cell was used to follow the nucleation and growth kinetics of corrosion products on X65 carbon steel surfaces in a carbon dioxide (CO2)-saturated 3.5wt.% NaCl brine at 80°C and a flow rate of 0.1m/s over a range of solution pH values (6.3, 6.8 and 7). In all conditions, FeCO3 was identified as the only crystalline phase to form. Electrochemical results coupled with post-test surface analysis indicate that at higher pH, larger portions of the surface become covered faster with thinner, more protective films consisting of smaller, denser and more compact crystals. The comparison between XRD main peak area intensities and FeCO3 surface coverage, mass and volume indicates a qualitative relationship between these parameters at each pH, providing valuable information on the kinetics of film growth.

Defect formation in MeV H+ implanted GaN and 4H-SiC investigated by cross-sectional Raman spectroscopy

Cross-sectional Raman spectroscopy is used to characterize the defect formation and the defect recovery in MeV H+ implanted bulk GaN and 4H-SiC in the high energy MeV ion-cut process. The Raman intensity decreases but the forbidden modes are activated at the damage region, and the intensity decrease is proportional to the damage level. The Raman spectrum is quite sensitive to detect the damage recovery after annealing. The main peak intensity increases and the forbidden mode disappears in both annealed GaN and 4H-SiC samples. The Raman spectra of GaN samples annealed at different temperatures suggest that higher annealing temperature is more efficient for damage recovery. While, the Raman spectra of SiC indicate that higher implantation temperature results in heavier lattice damage and other polytype clusters might be generated by high annealing temperature in the annealed SiC samples. The cross-sectional Raman spectroscopy is a straightforward method to characterize lattice damage and damage recovery in high energy ion-cut process. It can serve as a fast supplementary measurement technique to Rutherford backscattering spectrometry (RBS), nuclear reaction analysis (NRA) and transmission electron microscope (TEM) for the defect characterizations.

SiC Conversion Coating Prepared from Silica-Graphite Reaction

The β-SiC conversion coatings were successfully synthesized by the SiO(v)-graphite(s) reaction between silica powder and graphite specimen. This paper is to describe the effects on the characteristics of the SiC conversion coatings, fabricated according to two different reaction conditions. FE-SEM, FE-TEM microstructural morphologies, XRD patterns, pore size distribution, and oxidation behavior of the SiC-coated graphite were investigated. In the XRD pattern and SAD pattern, the coating layers showed cubic SiC peak as well as hexagonal SiC peak. The SiC coatings showed somewhat different characteristics with the reaction conditions according to the position arrangement of the graphite samples. The SiC coating on graphite, prepared in reaction zone (2), shows higher intensity of beta-SiC main peak (111) in XRD pattern as well as rather lower porosity and smaller main pore size peak under 1 μm.

Properties of Manganese(III) Ferrocenyl-β-Diketonato Complexes Revealed by Charge Transfer and Multiplet Splitting in the Mn 2p and Fe 2p X-Ray Photoelectron Envelopes.

A series of ferrocenyl-functionalized β-diketonato manganese(III) complexes, [Mn(FcCOCHCOR)3] with R = CF3, CH3, Ph (phenyl) and Fc (ferrocenyl) was subjected to a systematic XPS study of the Mn 2p3/2 and Fe 2p3/2 core-level photoelectron lines and their satellite structures. A charge-transfer process from the β-diketonato ligand to the Mn(III) metal center is responsible for the prominent shake-up satellite peaks of the Mn 2p photoelectron lines and the shake-down satellite peaks of the Fe 2p photoelectron lines. Multiplet splitting simulations of the photoelectron lines of the Mn(III) center of [Mn(FcCOCHCOR)3] resemble the calculated Mn 2p3/2 envelope of Mn3+ ions well, indicating the Mn(III) centers are in the high spin state. XPS spectra of complexes with unsymmetrical β-diketonato ligands (i.e., R not Fc) were described with two sets of multiplet splitting peaks representing fac and the more stable mer isomers respectively. Stronger electron-donating ligands stabilize fac more than mer isomers. The sum of group electronegativities, ΣχR, of the β-diketonato pendant side groups influences the binding energies of the multiplet splitting and charge transfer peaks in both Mn and Fe 2p3/2 photoelectron lines, the ratio of satellite to main peak intensities, and the degree of covalence of the Mn–O bond.