Emission Environment Scanning Electron Microscope Research Articles

UV laser-produced copper micro-mesh with superhydrophobic-oleophilic surface for oil-water separation

We report a method to fabricate micro-pore arrays on a copper sheet by a 355 nm UV nanosecond pulse laser, and investigate the effects of surface microstructures and micro-pore spacing on the wettability of the formed copper micro-mesh. We found that the surface was initially hydrophilic, but changed to superhydrophobic-oleophilic with water contact angle 151° and oil contact angle about 10° after exposed to ambient environment for 14 days. We analysed the surface morphologies of the processed samples with a three-dimensional profilometer, measured the water and oil contact angles, and characterized the surface by a field emission environmental scanning electron microscope (FESEM) and energy dispersive X-ray spectrometer (EDS). The surface chemistry changes were confirmed by X-ray photographic spectroscopy (XPS). Effective oil-water separation performance of the fabricated copper mesh was demonstrated. Learning from the natural change, we designed a coating material containing C8 long C–C (H) chain and coated onto the freshly prepared copper mesh to convert the surface property into a preferred superhydrophobic-oleophilic nature. This study provides a controllable methodology consisting laser processing and surface modification for making micro-pore copper mesh as a simple and effective method for oil-water separation.

Piston Rod Coating Material Study of Reciprocating Sealing Experiment Based on Sterling Seal

Sterling seal is a commonly used reciprocating seal, in which the PTFE ring of the seal and the surface material of the piston rod play an important role in the reciprocating sealing process. In this paper, a reciprocating sealing test bench was built, four sets of carbon fiber PTFE sealing rings were used to perform reciprocating sealing bench experiments with Cr-coated piston rods and DLC-coated piston rods. After the experiment, the used four sets of seals were taken as experimental samples, and a new, unused carbon fiber PTFE seal was taken as a reference sample. The surface topography, surface wear, and wear surface elements of the test specimens were measured by three-dimensional white light interference surface topography instrument, field emission environment scanning electron microscope, and field emission scanning electron microscope. Through experimental determination, it is found that the coating material is detached to form abrasive grains, which causes the surface of the sealing ring to wear. This paper also proposes optimization suggestions for the processing method of the sealing ring and the selection of the material of the piston rod coating.

Enhanced thermal conductivity interface by covalently bridging on cu-zn alloy with functionalized graphene through pulse electrodeposition

Special thermal conductivity bridging is conducted between metal matrix and graphene oxide (GO) with covalent bond (Cu-O-Si-O-C) from γ-glycidylether propyl trimethylsilane (GPTS) to decrease thermal resistance and weaken phonon scattering through interface. The implementation of this bridging process involves a pulsed electrophoretic deposition, in which the GPTS modified GO as thermal conductivity reinforcing material was deposited onto the Cu-Zn alloy. The composite morphology and interfacial structure by field emission environment scanning electron microscope shows that the GPTS-GO is uniformly deposited on the substrate surface, and there is no interlayer of the GPTS-GO/Cu differing from the GO/Cu without GPTS. Raman spectrum reveals the bonding of Cu-O-Si and Si-O-C to prove the bridging role of GPTS by structural defects of the graphene and the changes of relative characteristic peaks before and after modification, as well as the Fourier transform infrared spectrum results confirming the Cu-O-Si-O-C covalent bonds. Compared to the thermal stability and thermal conductivity by thermogravimetric analyzer from room temperature to a higher temperature of 150 °C for the GO/Cu sample without GPTS, the GPTS-GO/Cu exhibits significantly improved performances. The thermal conductivity achieves 415.2 and 361.9 W/mK at 50 °C to 150 °C, which is 5.01% and 6.00% higher than that of the GO/Cu, The thermal diffusion coefficient achieves 1.236 and 1.087 cm2/s at 50 °C to 150 °C, respectively.

The characteristics of nano-pore of the 3rd member shale from Dongying Formation of Paleogene in Liaozhong Sag

The reservoirs structure and pore characteristics of shale have greatly influenced the reservoir, adsorption and migration of oil and gas, and have become one of the important contents of reservoir physical characteristics evaluation. The organic-rich shales in the 3rd member shale of the Dongying Formation in Paleogene, Liaozhong sag, Bohai bay basin were studied in this paper. Firstly, the surface of shale sample was etched by argon ion polishing technology, and then the microscopic pore morphology was observed by field emission environment scanning electron microscope. The results show that: 1) the pores of shale reservoir in 3rd member shale of the Dongying Formation from Liaozhong sag are divided into inorganic pores (including intergranular pores, intragranular pores, interstratal pores and intercrystalline pores), organic pores and microfractures; 2) the intergranular pores are largely developed, intragranular pores and interlaminar pores are relatively developed, micro-cracks are less developed, and intergranular pores and organic pores are rarely developed.

Origin and geochemical implication of relatively high abundance of 17α (H)-diahopane in Yabulai basin, northwest China

Abstract Relatively high abundance of 17α (H)-diahopane has been detected in source rock extracts in the Yabulai Basin, a lacustrine basin in northwest China. Gas chromatography-mass spectrometry (GC-MS), X-ray diffraction (XRD) and Field emission environment scanning electron microscope imaging (FE-ESEM) were used in combination with conventional geochemical parameters to unravel the enrichment mechanisms. Significant variations of 17α (H)-diahopane concentrations detected in the Xinhe Formation with similar maturity inferred that thermal evolution is not the unique factor inducing the compound generating. The sedimentation of samples rich in 17α (H)-diahopane usually occur under suboxic conditions. Results of mineralogy analysis suggested that samples with high content of 17α (H)-diahopane are rich in carbonate minerals (about 20 wt %), which might deposit in brackish-saline water depositional environment. Relatively high content of gammacerane is also consistent with the experimental results of XRD. Based on the viewpoint of Moldowan et al. (1991), the regular hopanes may be the precursor of the rearranged hopanes, with the Wagner-Meerwein rearrangement as the mechanism. In this reaction, the critical factor of methyl migration is the production of carbocation starting with dehydroxylation. We suggested a general scheme for the generation of 17α (H)-diahopane in this study. In lacustrine sediments, suboxic and brackish environment could catalyze the methyl migration accompanied by carbonate deposit. Its geochemical implication can be used to reconstruct lacustrine paleoenvironment and contribute to a better understanding on oil-oil correlation, oil-source rock correlation and petroleum system study.

Evaluation of chemical treatments to tensile properties of cellulosic bamboo fibers

Acidified sodium chlorite (NaClO2) and sodium hydroxide (NaOH) solutions were successfully used to eliminate lignin and hemicellulose, respectively, from isolated bamboo fibers to investigate their microstructures, composition and micro-tensile properties in individual cellulose fibers. The results demonstrated that isolated fibers and chemically treated fibers clearly displayed different wrinkles, pores and microfibril aggregations on the cell wall surface. Field emission environmental scanning electron microscope images together with confocal scanning laser microscope measurements revealed that chemical treatments have a reduction effect on micro-tensile strength and modulus. Two methods of freeze-drying and air-drying produced varying interfaces and pores in microfibril aggregations and resulted in different tensile behavior. Notably, the reductions of Young’s modulus and tensile strength in freeze-drying (52.99 and 13.32%) fibers are larger than that (18.21 and 10.93%) in air-drying samples. These results suggest that most fractures occur in the weak interspaces or pores that are caused by the loss of matrix materials during chemical treatments.

Using ESEM to analyze the microscopic property of basalt fiber reinforced asphalt concrete

The basalt fiber staggered distribution in the asphalt concrete matrix and the bonding situation between asphalt are analyzed by images collected using field emission environmental scanning electron microscope (ESEM) test equipment. The results show that bonding of the fiber and the asphalt binder is very good and there is a strong binding force of chemical bonding connections between the two; the lipophilicity of basalt fiber is very good, the wrapped cover ability of asphalt for fiber is very strong; basalt fiber forms the local space network structure in the asphalt concrete matrix, effectively overcome the relative slip between the particles, connect the damaged parts into a whole; basalt fiber across internal micropores, and the internal defects in material can be remedied. At the same time, crack resistance mechanism of the fiber to internal micro cracks is qualitatively explained according to the magnitude of the stress intensity factor Kf.

Changes in bamboo fiber subjected to different chemical treatments and freeze-drying as measured by nanoindentation

The effects of chemical treatments (H2O2 + CH3COOH, acidified NaClO2, and NaOH) and freeze-drying on bamboo fibers were studied at a submicron level, to characterize chemical and mechanical changes to the secondary cell wall. Specifically, a field emission environmental scanning electron microscope (FE-ESEM) and imaging fourier transform infrared spectroscopy (FTIR) were used to demonstrate degradation in morphology and molecular structure, and nanoindentation was used to track changes in micromechanical properties. The results showed that cellular structures after chemical treatments clearly displayed wrinkles, pores, and microfibrils. The decreased bands at 1508 cm-1 and 1426 cm−1 showed that lignin was degraded on treatment of H2O2 + CH3COOH and acidified NaClO2, which directly resulted in a decrease in hardness (H) in the secondary cell wall for treated fibers. In addition, a diminishing peak at 1733 cm−1 caused by NaOH solution indicated that hemicellulose was seriously degraded. It resulted in a decreased modulus (E r) by 13.71 % in bamboo fibers, while no obvious reduction was observed in the first two steps.

Preparation and characterization of solid lipid microparticles with liquid crystal structure

ABSTRACTThe aim of this study was the preparation and characterization of solid lipid microparticles (SLMs) with liquid crystal structure. In order to observe the morphology of SLMs, environmental emission scanning electron microscopy was employed. And the structure of particles measured by polarized light optical microscopy and X-ray diffraction. Differential scanning calorimetry (DSC) was used to measure the crystallinity. Karl Fischer Titration were used to measure the micro amount of water content. The optimal formation was prepared. The influence of homogenization rate, emulsification temperature, concentration of NaCl, co-emulsifier type and concentration on particle size was discussed.

Effect of Additive on Surface Properties of Solution Coated PZT Ferroelectric Film

In order to meet the requirements of large-scale industrial production, a hybrid sol-gel route which was used to fabricate PZT thick film attract a lot due to its low price [1]. However, surface imperfections, such as crack, pore and thickness nonuniform must be controlled. In this work, in order to get perfect film additive such as formylamine, acetic acid, polyvinylpyrrolidone (PVP) were studied. The surface morphologies were characterized by the Dimension 3100 atomic force microscope (AFM) and the Quanta 400 FEG Field emission environmental scanning electron microscope (SEM) respectively. The effect of additives on film thickness was studied by the JA.Woollam MD2000D Elliptic polarization spectrometer. The results show us that the additive can improve the the defects such as crack, porous and thickness nonuniform of PZT films effectively. We got crack-free, nonporous and compact PZT piezoelectric films when the PZT sol was acetic acid 20%, formylamine 15% and PVP 1% inside.

Preparation Assisted via Thermal Stress and Electrochemical Performance of Graphene Nano-Sheets as Anode Materials for Lithium-Ion Batteries

Via a simple thermal stress assist process, the high-quality graphene was successfully obtained. The microstructure, morphology and the electrochemical performance of the as-prepared products were characterized by x-ray diffraction (XRD), field emission environment scanning electron microscope (SEM), Micro-Raman Spectroscopy System, element analysis system and LAND battery program-control test system respectively. The results show that the as-prepared products are uniform graphene nano-sheets (GNs) with large and smooth surface, and that the GNs, as an anode material for lithium-ion cell, exhibit good cyclic performance, which imply that the lithium ions and GNs have formed a relative stable structure to large degree. A possible form mechanism of the high-quality GNs is proposed.

Effect of alkali metal Oxides on viscosity and crystallization of the MgO–Al2O3–SiO2 glasses

MgO–Al2O3–SiO2 glasses were prepared by using TiO2 and ZrO2 as nucleation agents, and 2% (wt%, the same as below) content of alkali metal oxide was added. The viscosity of MAS glass melt was investigated by the rotating crucible viscometer, and the melting temperature and activation energy for viscous flow of the melt were derived by the Arrhenius equation. After melting and casting, the glass samples were crystallized in the temperature range from 880 to 1145°C. The prepared glass-ceramics presented transparent to opaque with the increasing of crystallization temperature, which had been investigated by X-ray diffraction and field emission–environment scanning electron microscope. The results showed that the melting temperature of glass containing 2% Na2O was about 1585°C. The MgAl2O4, ZrTiO4 and the sapphirine crystalline phases precipitated from matrix glass successively as the crystallization temperature raising. When 1% Na2O was replaced by Li2O, the melting temperature of the glasses decreased to 1508°C, meanwhile, the main crystal phase changed from MgAl2O4 to high-/low—quartz solid solution, therefore, the crystallization behavior was uncontrollable and the transparent glass ceramic cannot be obtained. As 1% K2O substituted for Na2O, the melting temperature decreased to 1573°C. The adding of K2O could broaden the crystallization temperature range of preparing transparent glass-ceramics. After crystallized at the range from 900°C to 1000°C, the fine spinel (MgAl2O4) crystals which had average size about 25nm precipitated from matrix glasses, and the specimens kept transparent.

Preparation and Growth Mechanism of Chrysanthemum-Like ZnO Nanowire Clusters

With sodium hydroxide (NaOH), ammonia water (NH3 x H2O) and hexamethylenetetramine (HMT, C6H12N4) respectively as alkaline source material, a simple hydrothermal process was employed to prepare chrysanthemum-like ZnO nanowire clusters. The morphologies and crystalline structures of the as-prepared products were investigated by X-ray diffractometer (XRD), field emission environment scanning electron microscope (SEM), and high-resolution transmission electron microscopy (TEM). The experimental results indicate that the as-prepared products all have three-dimensional chrysanthemum-like structure in which the petal-like nanowires are ZnO single crystalline with hexagonal wurtzite structure, that the flower bud saturation degree F(d) is slightly different under different alkaline source materials, and that the proposed growth mechanism of chrysanthemum-like ZnO nanowire clusters is reasonable.

Polymeric blend nanocomposite membranes for ethanol dehydration—effect of morphology and membrane–solvent interactions

Nanocomposite membranes (NCMs) of sodium alginate/poly(vinyl pyrrolidone) blend polymers incorporated with varying concentrations of phosphotungstic acid (H3PW12O40) (PWA) nanoparticles have been prepared and used in ethanol dehydration by the pervaporation (PV) technique. Effects of filler concentration, temperature and feed water composition have been investigated to understand the PV performance of the membranes in terms of separation factor and flux. Surface morphology/energy, free volume, collective and complex range of interactions between the permeants and membranes as well as membrane swelling were studied. Arrhenius activation parameters for diffusion and permeation have been estimated. Membranes were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), and environmental emission scanning electron microscopy (ESEM). Size of the PWA nanoparticles was determined by a particle size analyzer. Surface free energies calculated from contact angles as well as free volume and fractional free volume parameters obtained from positron annihilation lifetime spectroscopy (PALS) have been used to understand the membrane transport phenomenon in terms of membrane–permeate interactions.

Effect of Sb-doping on the morphology and dielectric properties of chrysanthemum-like ZnO nanowire clusters

Chrysanthemum-like ZnO nanowire clusters with different Sb-doping concentrations were prepared using a hydrothermal process. The microstructures, morphologies, and dielectric properties of the as-prepared products were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), field emission environment scanning electron microscope (FEESEM), and microwave vector network analyzer respectively. The results indicate that the as-prepared products are Sb-doped ZnO single crystallines with a hexagonal wurtzite structure, the flower bud saturation degree Fd is obviously different from that of the pure ZnO nanowire clusters, the good dielectric loss property is found in Sb-doped ZnO products with low density, and the dielectric loss tangent tanδe increases with the increase of the Sb-doping concentration in a certain concentration range.

Dispersibility and chemical bonds between multi-walled carbon nanotubes and poly(ether ether ketone) in nanocomposite fibers

A series of multi-walled carbon nanotubes (MWNTs)/poly(ether ether ketone)(PEEK) nanocomposite fibers were fabricated by mixing, melt extruding PEEK with different loadings and species of MWNTs, and melt-spun the blended chips. Nanocomposite fibers were heat-stretched and heat-treated. The morphology and dispersibility of MWNTs in nanocomposite fibers were observed using a field emission environmental scanning electron microscope (FESEM) and a transmission electron microscope (TEM). The thermal and crystallization behavior of nanocomposite fibers were characterized using differential scanning calorimetry (DSC) and an X-ray diffractometer (XRD). Mechanical properties were tested using a tensile strength tester. MWNTs tend to aggregate when the loading exceeds 0.8 wt%. Functional groups on MWNTs improve the hydrophobicity and the dispersibility of MWNTs in PEEK matrix. The enhancement of mechanical properties depends on the loading and species of functional groups. The most effectively reinforced effect is in the sequence, carboxylic MWNTs (MWNT–COOH) > hydroxyl MWNTs (MWNT–OH) > MWNTs, which can be explained by the strong hydrogen bonding and the affinity between MWNT–COOH and PEEK, MWNT–OH and PEEK, and possible formation of a chemical bond between MWNT–COOH and PEEK. A nanocomposite fiber with excellent mechanical property was fabricated using 0.8 wt% MWNT–COOH as filler. The Young's modulus is 1.7 GPa; and the stress is 648 MPa.

Fabrication and optical properties of needle-like ZnO array by a simple hydrothermal process

A simple low temperature hydrothermal process was employed to fabricate the needle-like ZnO array in the diluted butyl amine. The microstructure, morphology and the photoluminescence property of the as-prepared products were characterized by x-ray diffraction (XRD), transmission electron microscope (TEM), field emission environment scanning electron microscope (SEM) and photoluminescence spectrum (PL). The results show that the needle-like ZnO crystals are hexagonal wurtzite monocrystal with slender figure and smooth surface. A possible growth mechanism of the needle-like ZnO array related to the diluted butyl amine is proposed. The PL spectrum of the needle-like ZnO array shows a strong blue light emission at 437 nm and a relatively low ultraviolet emission at 377 nm.

Heterogeneous reaction of formaldehyde on the surface of γ-Al2O3 particles

Abstract Formaldehyde is one of the most important carbonyl organic compounds. Heterogeneous reactions of formaldehyde on the surface of oxides of crustal elements could be an important sink for formaldehyde in the atmosphere. In this study, the kinetics of the heterogeneous reaction of formaldehyde on the surface of γ-Al 2 O 3 was investigated in situ by diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) combined with ion chromatography (IC), X-ray diffraction (XRD), and field emission environmental scanning electron microscope (ESEM). The adsorbed species, formate, dioxymethylene, polyoxymethylene, and formaldehyde, on γ-Al 2 O 3 particles, were identified by infrared spectroscopy. On the surface of γ-Al 2 O 3 particles, formaldehyde is first oxidized to dioxymethylene, which is further oxidized to formate. The reaction order was determined as 0.74 ± 0.05, and the initial reactive uptake coefficients at room temperature were calculated with the geometric and Brunauer–Emmett–Teller specific surface areas as (3.6 ± 0.8) × 10 −4 and (1.4 ± 0.31) × 10 −8 , respectively. The influences of oxygen concentration, humidity, and temperature on the reaction products and reactive uptake coefficients were studied. The results indicated the reaction is independent of the O 2 concentration within the range used in this experiment, and humidity is negatively correlated with the uptake of formaldehyde by the particles. Temperature not only plays a role on the heterogeneous reaction products but also is positively correlated with the uptake rate of formaldehyde by γ-Al 2 O 3 particles in the troposphere. The apparent activation energy of the reaction was determined.

Effect of Mn-doping on the growth mechanism and electromagnetic properties of chrysanthemum-like ZnO nanowire clusters

Chrysanthemum-like ZnO nanowire clusters with different Mn-doping concentrations are prepared by a hydrothermal process. The microstructure, morphology and electromagnetic properties are characterized by x-ray diffractometer high-resolution transmission electron microscopy (HRTEM), a field emission environment scanning electron microscope (FEESEM) and a microwave vector network analyser respectively. The experimental results indicate that the as-prepared products are Mn-doped ZnO single crystalline with a hexagonal wurtzite structure, that the growth habit changes due to Mn-doping and that a good magnetic loss property is found in the Mn-doped ZnO products, and the average magnetic loss tangent tanδm is up to 0.170099 for 3% Mn-doping, while the dielectric loss tangent tanδe is weakened, owing to the fact that ions Mn2+ enter the crystal lattice of ZnO.

Effect of polyacrylamide on morphology and electromagnetic properties of chrysanthemum-like ZnO particles

Through hydrothermal process, the chrysanthemum-like ZnO particles are prepared with zinc acetate dihydrate (Zn(CH3COO)2·2H2O) and sodium hydroxide (NaOH) used as main resources under the different concentrations of surfactant polyacrylamide (PAM). The microstructure, morphology and the electromagnetic properties of the as-prepared products are characterized by high-resolution transmissïon electron microscopy (HRTEM), field emission environment scanning electron microscope (FEESEM) and microwave vector network analyzer, respectively. The experimental results indicate that the as-prepared products are ZnO single crystalline with hexagona wurtzite structure, that the values of slenderness ratio Ld are different in different PAM concentrations, and that the good magnetic loss property is found in the ZnO products, and the average magnetic loss tangent tan δu increases with PAM concentration increasing, while the dielectric loss tangent tan δe decreases.