Influence Of Preparation Process Research Articles

Influence of preparation processes with or without long-time homogenization heat treatment on performance of Nd–Fe–B HDDR products

We investigated the influence of hydrogenation-disproportionation-desorption-recombination (HDDR) preparation processes, with or without long-time homogenization heat treatment, on the microstructure and hard magnetic properties of Nd12.7B6.5Co2.1Cr0.1Al0.5Nb0.3Ga0.5Fe77.3 powders/bonded magnets. Hard magnetic properties such as remanence (Br = 1.01 T), coercivity (Hcj = 949.39 kA/m), and maximum magnetic energy product (BH)max = 181.54 kJ/m3 were achieved for HDDR bonded magnets with homogenization heat treatment. In contrast, magnets prepared without homogenization heat treatment exhibited Br = 0.65 T, Hcj = 854.69 kA/m, and (BH)max = 66.98 kJ/m3. The notable decrease in remanence for magnets prepared without homogenization treatment is attributed to the presence of α–Fe in the parent alloy, which inhibits the hydrogenation-disproportionation process and consequently affects the orientation of the crystallographic texture. Furthermore, we fabricated bonded quadrupole magnetic rings using HDDR powder prepared with homogenization heat treatment. The study also explored the relationship between disproportionation temperature and surface magnetic field intensity for these quadrupole magnetic rings.

Influence of preparation processes on the droplets size characteristics and storage stability of emulsified asphalt

Influence of preparation processes on the droplets size characteristics and storage stability of emulsified asphalt

Influence of Preparation Processes on the Resistivity of Porous Ti Based ATO

Influence of Preparation Processes on the Resistivity of Porous Ti Based ATO

Novel low-frequency microwave absorber of Sn-Fe-O multiphase compounds combined with Salvia miltiorrhiza Bunge-derived biochar

Superfluous low-frequency microwave radiation becomes a serious problem gradually at current age, herein, the Sn-Fe-O multiphase compounds were combined with novel biochar by using Salvia miltiorrhiza Bunge's leaves as carbon source, which can realize the recycling of this useless Chinese medicinal waste for economy. Also, the influence of preparation process on the final components, structures and properties in composites have been evaluated, the P2 composite possesses the optimal electromagnetic absorbing property i.e. the maximum reflection loss achieves −45.09 dB at 0.48 GHz with efficient absorbing bandwidth of 0.14–1.16 GHz at the matching thickness of 2 mm, moreover, a broad efficient absorbing bandwidth of 0.86–3 GHz can obtained for only 0.71 mm as well. The outstanding absorption of this sample can be ascribed to the synergistic effect of multiple low-frequency absorption mechanisms such as nature resonance, eddy current, conduction and electron hopping, multi-ply interfacial polarization etc., suggesting its superiority for being applied as a new-type low frequency electromagnetic wave absorber for practical use.

Optical properties and surface dynamics analyses of homojunction and hetrojunction Q/ITO/ZnO/NZO and Q/ITO/ZnO/NiO thin films

The aim of the present study is to verify how alternations of annealing temperatures modify optical and micromorphological properties of n-ZnO/p-NZO and n-ZnO/p-NiO multilayers. As can be seen, the optical analysis of homojunctions and hetrojunction thin films shows a red shift by increasing annealing temperature which means that annealing can shift absorption edge coefficient to the lower values of energies. Also, the effective parameters on optical properties of homo- and hetrojunction thin films such as optical band gap, Urbach energy, steepness parameter, and skin depth have been studied by their transmittance spectra. Moreover, the micromorphology of n/p ZnO homo- and heterojunctions transparent diodes have been studied by atomic force microscopy in combination with modern image processing techniques. The nano scaled stereometric analysis provides significant insights into the influence of preparation process on surface texture geometry. According to the results extracted from AFM micrographs by MountainsMap® software, it is observed that Q/ITO/ZnO/NZO sample with 300 °C annealing temperature has the normal distribution of peaks with the highest percentage of isotropy. In addition, it is observed that Q/ITO/ZnO/NiO with 500 °C annealing temperature has the most regular topography.

Influence of Preparation Process of Z-N Catalyst on Catalyst Performance and Optimization Measures

Influence of Preparation Process of Z-N Catalyst on Catalyst Performance and Optimization Measures

Influence of preparation process on the transparency of CsI microcolumns in the structured CsI scintillation screen based on oxidized silicon micropore array template

The structured CsI scintillation screens based on oxidized silicon micropore array templates can maintain high spatial resolution in X-ray imaging while increasing their thickness. However, the detection efficiency of the screens is not only related to their thickness, but also related to the transparency of the CsI scintillation microcolumns in the screens, because it affects the output of the scintillation light. In this work, the hexagonal array arranged structured CsI scintillation screens based on oxidized silicon micropore templates with pore pitch about 4.3μm and diameter about 3.0μm were fabricated by vacuum melting and pressure injection method. In order to improve the transparency of the CsI microcolumns, the effects of filling temperature and pressure on the morphology, crystallinity, X-ray excited optical luminescence (XEOL) and transparency of the CsI scintillation microcolumns were studied after a preliminary research on TG-DSC, melt viscosity and bulk preparation of CsI material. The results show that with the increase of filling temperature, the cracks and microbubbles in the filled CsI microcolumns become less or even disappear under the filling pressure of 6 MPa, and the crystallinity of the microcolumns becomes better. Meanwhile, the intensity of the XEOL becomes stronger. The light attenuation coefficients of the CsI scintillation microcolumns prepared at different filling temperature were derived by Geant4 Monte Carlo simulation toolkit according to the results of XEOL. The light attenuation coefficient decreases significantly as the filling temperature increases. When the filling temperature reaches 660 °C, the light attenuation coefficient of the CsI microcolumns has dropped below 0.002μm−1. Such a low light attenuation coefficient is completely suitable for X-ray imaging of the structured high-resolution CsI scintillation screens based on oxidized silicon micropore array templates that have been developed.

Preparation, characterization and investigation of molecular films coated on diamond-like carbon substrate

For the successful application of boundary lubrication, detailed investigations about the influence of preparation process on molecular films are needed. In this paper, a specially designed device was used for the film preparation. The scanning electron microscope (SEM) combined with atomic force microscope (AFM) was employed to characterize the surface morphology and nanotribological behavior of molecular films. After the liquid phase deposition, molecular films are randomly and densely distributed over Ti-doped diamond-like carbon (Ti-DLC) substrates. Through rigorous surface treatments, island-like molecular films were finally achieved on substrate surfaces. The surface friction of molecular films is obviously lower than that of Ti-DLC surfaces. Then, pin-on-disk tribotests were performed to study the macrofriction behavior of molecular films under different preparation parameters. Based on the orthogonal experiment, the effect of five preparation parameters (solution weight percent, smearing force and processing time of three smearing steps) on initial friction coefficient of molecular films was investigated. The results indicated that the order of significance levels is as follows: processing time of the second smearing step > solution weight percent > processing time of step 1 > processing time of step 3 > smearing force. For the purpose of friction reduction, the appropriate level ranges are 0.75% (Solution), 2.5 N–15 N (Force), 1 min–10 min (Step 1), 1 min–2 min (Step 2) and 1 min, 2 min, 5 min and 15 min (Step 3). The initial friction coefficient under the optimized conditions is around 0.112, and the equilibrium friction coefficient is around 0.162, which is lower than that of unlubricated Ti-DLC substrates.

Use of CdTe Quantum Dots as Heat Resistant Temperature Sensor for Bearing Rotating Elements Monitoring

The thermal characteristics of bearing rotating elements are essential for the service evaluation of bearing. However, the existing monitoring methods are limited by bearing internal complex structure and extreme operating environment. Hence, based on the monitoring technology of CdTe quantum dots (QDs) sensor, an improved QDs sensor was fabricated by process optimization and polymers coating, which enables bearing rotating elements thermal monitoring for extreme working condition. First, the principle of the measurement was introduced and the existing problems were analyzed. Then, the influence of preparation process on temperature-dependent photoluminescence (PL) spectra of CdTe QDs was investigated. The performance improvement methods of the QDs sensor, both organic coating and inorganic coating, were investigated. The fabricated sensor named CdTe@PVA presents remarkable improved performance in fluorescence intensity, highest tolerable temperature and stability. In the end, a rolling bearing experimental rig was set up and the temperature of the bearing cage at different rotation speeds were captured by using the proposed CdTe@PVA sensor.

Influence of preparation processes on thermophysical properties of molten salt

Molten salt has been widely studied as a heat storage material, but some properties of molten salt reported in different literature studies are not completely consistent. In order to make data comparison more convenient and improve the effectiveness of scientific research communication, reasons for the data discrepancy were studied. In this work, the relationship between the preparation of NaNO3–KNO3 binary molten salt and thermophysical properties was studied. Six preparation methods including static melting method, dissolution method, stirring evaporation method, boiling evaporation method, tap water dissolution method, and grinding method were adopted. The thermophysical properties studied include melting range, latent heat, and decomposition temperature. The experimental results show that all the above methods can be used to prepare NaNO3–KNO3 molten salt with good thermophysical properties except for the dissolution method, which would lead to uneven distribution of compositions. For the grinding method, it is found that the properties of molten salt are stable when the particle size is less than 96 µm. Samples prepared by these feasible methods have a melting point range of 220–240 °C. Their latent heat is more than 100 J/g and the decomposition temperature up to ∼580 °C. Thermal properties are affected to some extent by the preparing process, such as impurities in the solvent or the drying process.

Biowaste-based porous carbon for supercapacitor: The influence of preparation processes on structure and performance

Here, a series of porous carbon based supercapacitor electrode materials have been synthesized by means of pyrolysis and hydrothermal methods combining with KOH activation using the biomass wastes mung bean husks as resources. The influence of synthesis process on the morphology, structure and supercapacitor performance of mung bean husks derived porous carbons has been investigated systematically. Especially, it is found that these oxygen-containing groups on the biochar play a crucial role in fabricating the three-dimensional (3D) hierarchical porous structure carbon. The original bio-structured porous carbon (PC3-600), the 3D architecture porous carbon (HPC2-700) and the porous carbon block (HPPC2-700) have a high specific surface area, and the former mainly contains micropores and the latter two possess multistage pores. The specific capacitance of PC3-600, HPC2-700 and HPPC2-700 is respectively up to 390 F g−1, 353 F g−1, 304 F g−1 at 1 A g−1, and still maintains as high as 287 F g−1, 270 F g−1 and 235 F g−1 with corresponding retention ratio of 73.5%, 76.48%, 77.3% even at a high current density of 50 A g−1. HPC2-700//HPC2-700 symmetric supercapacitor achieves a high energy density of 20.4 Wh kg−1 at 872 W kg−1 in 1 M Na2SO4 electrolyte.

Influence of Preparation Process on Briquette and Form Coke Compressive Strength

This paper investigated preparation process of briquette by using starch and bentonite as composite binder. It also studied the impact of pulverized coal particle size, coking particle size, compacting pressures, moisture content on the strength of briquette and form coke. The result showed that coking coal particle size was the main influence factor. And the optimum conditions of molding process were as follows: low rank pulverized coal particle size was less than 0.63mm, coking coal particle size was less than 0.28mm, compacting pressure was 60 kN, molding moisture content was 12%. Under the optimal conditions, compressive strength of briquette and form coke was 3470 N/ball and 2910 N/ball, respectively.

Reconstructing historical recipes of linseed oil/colophony varnishes: Influence of preparation processes on application properties

Abstract Mixtures of siccative oil with Pinaceae resin are among the most widespread natural formulations used for varnishing before the introduction of synthetic varnishes in the 1900s. In this work, varnishes containing linseed oil and colophony in different proportions were recreated. Heat treatment is necessary to mix the two components; time and temperature of heating have to be carefully chosen, in accordance with proportions, in order to obtain homogeneous and translucent mixtures. The effects of heat treatment on the mixtures’ properties were evaluated for five temperatures and three durations fitting these requirements, and various proportions were prepared. The application properties of the various reconstitutions, including a varnish prepared by a violin-maker, were studied through rheological measurements. These data were used to discuss the varnishes’ brushing, leveling and sagging properties, by comparing them to industrial criterions. Intensifying the heat treatment by increasing its temperature and length was shown to exponentially increase the mixtures’ viscosity. Size exclusion chromatography was used to evidence the polymerization reactions responsible for this behavior. The effect of colophony proportions was also investigated: colophony acts as a thickener increasing the mixtures’ viscosity. All the varnishes exhibited thixotropic behavior. The higher the colophony proportion, the lowest is the shear rate at which shear-thinning behavior occurs, and the longer it takes to regain the initial viscosity. The easiest mixtures to apply as a coating were the ones with intermediate colophony proportions (33 to 58 wt%). Also, varnishes containing lower colophony proportions (20 wt%) could conveniently be coated if they were prepared using a strong heat treatment (long time and/or a high temperature). In the same way, higher colophony proportions (66 wt%) could be used if the mixture was heated at a lower temperature. These selected mixtures have a low viscosity at high shear rates, allowing brushing them easily. The time for viscosity recovering is long enough to allow good leveling and they have a quite high zero-shear rate viscosity, acting against sagging.

Influence of Preparation Process on the Performance of Strain Hardening Cementitious Composite

The modification of matrix is an important method to improve the mechanical properties of strain hardening cementitious composite (SHCC). The influence of the properties of the matrix water binder ratio (W/B) and fresh state rheology on SHCC tensile behaviors are useful for the SHCC design. The W/B influences only on tensile strength, but not the stain capacity, if the fresh state workability remains uniform. On the other hand, the workability has a significant influence on SHCC strain capacity through its influence on the fiber distribution. Consequently, it is important to cast SHCC carefully and make sure the even fiber distribution to insure the bridging function and mechanical properties of SHCC.

Systematic Investigation of the Influence of Preparation Process and Target Composition on Structure and Magnetic Properties of Nd–Fe–B Thin Films

Anisotropic Nd–Fe–B films with high performance have been prepared by dc magnetron sputtering on heated Si(100) substrates. The influences of sputtering power, target composition, deposition temperature, and annealing condition on the magnetic properties of Nd–Fe–B films were investigated systematically. The X-ray diffraction patterns showed that the Nd–Fe–B grains are aligned with their c-axes pointing normal to the film plane. It was found that the magnetic properties are sensitive to the target composition, deposition temperature, and sputtering power. The maximum energy product achieved (378 kJ/m3) is comparable with that of high-quality Nd–Fe–B sintered magnets.

Preparation and Performance of SiC Foam Ceramic/Fe Matrix Co-continuous Phase Composites

SiC foam ceramic/Fe based co-continuous phase composites were prepared by squeeze casting method using oxidized SiC foam ceramic.Then the prepared composites were annealed.The influence of preparation process and SiC volume fraction on microstructures and mechanical properties of the composites were investigated.Results show that a SiO2 barrier film of 1 mm in thickness on the surfaces of SiC foam can form after oxidizing at 1250°C for 48 h,which then can efficiently prevent the formation of a brittle intermetallic compound Fe3 Si at the interface of Fe matrix and SiC during the preparation of composites.As a result,the flexural strength of composites was increased by 100% and compressive strength by 18%.The thickness of SiO2 film was increased after oxidizing at 1250°C for 72 h,and a thicker SiO2 film may induce mismatch of thermal expansion coefficient between SiO2,Fe and SiC,which thereby resulted in the increase of residual stress.Therefore,the mechanical properties of composites were decreased slightly.The residual stress could be relieved after annealing of composites at 600°C for4 h,which improved the mechanical properties of composites.The function of bridging and deflecting crack of metal matrix is big for the composite with small SiC volume fraction,which is in turn beneficial to the enhancement of the flexural strength and flexural strain.For the composite with the higher SiC volume fraction,the size of SiC skeleton became bigger and the load- carrying capacity was strengthened,thereby its compressive strength was increased.

Influence of Preparation Process on Morphology and Conductivity of Carbon Black-Based Electrospun Nanofibers

In this work, three different methods of preparation of polyacrylonitrille (PAN) with carbon black (CB) solutions further used in electrospinning for producing conductive fiber mats are discussed. CB is used as conductive filler. Content of CB in polymer matrix is varied, CB/PAN = 1/2, 1/1, and 3/2. The solution properties and obtained fiber morphology are analyzed. The effect of preparation on fiber morphology and conductivity is analyzed, as well as the effect of sonication on solution properties, morphology, and conductivity of PAN+CB samples.

Influence of preparation process on electrocatalytic activity of Ti/IrO2+MnO2 anodes for oxygen evolution in 0·5M Na2SO4 solution

The Ti/IrO2(x)+MnO2(1−x) anodes have been prepared by thermal decomposition of an H2IrCl6 and Mn(NO3)2 hydrosolvent. A four-factor and three-level orthogonal experiment is designed to optimise the preparation process of Ti/IrO2+MnO2 anodes for oxygen evolution in 0·5M Na2SO4 solution. Surface characteristics and electrocatalytic activity of Ti/IrO2+MnO2 anodes are investigated by a field emission scanning electron microscope and cyclic voltammetry. The orthogonal analysis indicates the order from the main to minor factor is thermal decomposition temperature, matrix etching time, Ir4+/Mn2+ mole ratio and total metal concentration of the precursor. Further optimisation experiments are also performed for the two main factors (thermal decomposition temperature and matrix etching time) based on the orthogonal experimental result. As a result, an optimal technological combination of 400°C×45 min×6∶4×0·3 mol L−1 is obtained. Moreover, a brief morphological verification is carried out.

The Process Optimization and Structural Analysis of Gasochromic Thin Films Derived by Peroxopolytungstic Acid

The sol-gel method with a combination of dip-coating process was employed to prepare peroxopolytungstic acid gasochromic thin films. The influence of preparation process on the structural and gasochromic durability was then discussed. We found that hydrogen peroxide content shown a significant impact on the structure of tungsten oxide thin films, which directly determined the gasochromic durability

Understanding the Effect of the Preparation Process on the Electrochemical Properties of 0.25Li<sub>2</sub>MnO<sub>3</sub>∙0.75LiNi<sub>1/2</sub>Mn<sub>1/2</sub>O<sub>2</sub> by Rietveld Refinement Method

0.25Li2MnO3•0.75LiNi1/2Mn1/2O2solid solution was prepared via a two-step calcination technique. No appreciable difference between the end products can be detected from the X-ray diffraction patterns including the superstructure reflections. However, the material prepared from preheating the precursor at 450°C for 4h in N2 delivers a high first charge capacity of 287mAhg-1between 2.5and 4.8V at 0.5C, while the samples obtained from preheating the precursor for 10h in air exhibit a low capacity of 199 mAhg-1and an undetectable plateau around 4.5V in the initial charge curve. With an aim to identify the influence of preparation process on the structural and electrochemical properties, Rietveld refinement method was performed on the detailed structure testing with the model integrating R m layered rock salts and Fd m cubic ones. The end products prepared from precalcining the precursor in N2 shows low proportion of Fd m domain about 8.0% and larger Li-O slab space in dominating R m rock salts. By contrast, the samples obtained from prolonging the process-prheating time to 10h in air consists of 12.7% Fd m cubic rock salts and 87.3% R m layered ones. The observations indicate that the samples obtained from different precursor-preheating process appear a variation in the local environment of Li+ insertion/extraction, which give an evidence on their electrochemical lithiation/delithiation process shown in the CV curves.