S-4800 Scanning Electron Microscope Research Articles

BiO 2-x Nanosheets with Surface Electron Localizations for Efficient Electrocatalytic CO 2 Reduction to Formate

BiO _2-x Nanosheets with Surface Electron Localizations for Efficient Electrocatalytic CO ₂ Reduction to Formate

Overcharge to Remove Cathode Passivation Layer for Reviving Failed Li–O 2 Batteries

Overcharge to Remove Cathode Passivation Layer for Reviving Failed Li–O ₂ Batteries

Ultrastructure of androconia and surrounding scales of nine species of Hesperiidae (Lepidoptera).

The ultrastructure of androconia and their surrounding scales of nine species in nine genera across four subfamilies of Hesperiidae is studied. This provides a basis for the classification and identification of some genera and species. The wing surface of the scent glands patches was cut with scissors, observed and photographed under an S-4800 scanning electron microscope (at 10.0 kV accelerated pressure). There were significant differences in the types of scent glands patches across subfamilies. The scent glands patches of Pyrginae and Dudaminae are mainly in the costal fold of the forewing, while those of Coeliadinae and Hesperiinae are mainly in the line or circular stigma on the wing surface. The length, breadth and aperture of the androconia were further measured and the data are analysed by variance and multiple comparisons. There are significant differences amongst the subfamilies, except for Dudaminae and Pyrginae. In Hesperiinae, Telicotacolon (Fabricius, 1775) and Ampittiavirgata (Leech, 1890) have no significant difference in the aperture of the androconia, but are significantly different from Thymelicusleoninus (Butler, 1878). There are significant differences in the aperture between Pyrgusalveus’s (Hübner, 1803) androconium and the second androconium of Loboclabifasciata (Bremer & Grey, 1853), but not with the first androconium of Loboclabifasciata. The morphology of androconia in the scent glands patches is very similar in Hesperiinae; all are rod-shaped and paddle-like. The scale types around the scent glands patches are different, but there are one or two similar types. To a certain extent, the aperture of the androconia reflects the genetic relationships between subfamilies and species. The differences in scale type and structure of scent glands patches can be used as a reference for the classification of subfamilies and genera in Hesperiidae.

Gas-Induced Phase Transition of Dipeptide Supramolecular Assembly

Gas-Induced Phase Transition of Dipeptide Supramolecular Assembly

Characteristics and Implications of Nanocoatings on Gouges in a Seismically Active Fault Zone.

Using a ZEISS Axio Scope A1 ordinary polarizing microscope, a ZEISS Sigma 300 scanning electron microscope and a HITACHI S4800 scanning electron microscope, we observe micro/nanocharacteristics of slip planes in gouges sampled from the Tanlu fault zone, the Haiyuan fault zone and several other Late Pleistocene active faults, such as the Haiyang fault, the Shuangshan-Lijiazhuang fault and the Xintai-Mengyin fault, in Shandong Province. Based on microscopic observation of gouges, a straight slip zone is a sign of seismic stick slipping. According to scanning electron microscopy results, the surface of gouges is commonly covered by nanocoatings. Such coatings feature nanoparticles, aggregations, scratches, grooves, cracks and "silver lines." According to the characteristics of nanomaterials, we believe that nanocoatings on gouges could help rapidly unload tectonic stress in the process of energy accumulation and weaken the strength of the active fault, which is beneficial to creep slipping and has a weakening effect on seismogenesis.

CONDENSER STRUCTURES BASED ON BARIUM TITANATE FILMS FORMED BY SOL-GEL METHOD

The objective of the work is investigation the dielectric permittivity and dielectric loss tangent of BaTiO3 films in a capacitor structure formed by sol – gel method on a Si/TiOx/Pt substrate. The basis of this capacitor is a four-layer film of barium titanate xerogel with a thickness of about 200 nm. The film was synthesized by sol-gel method at a final annealing temperature 750 °C. The problems related to the development of method of forming multilayer capacitor structures, the analysis of the morphology and phase composition of BaTiO3 film, and also the measurement of the capacitance-voltage characteristics in the frequency range 10 kHz – 2 MHz have been solved. Morphology of the films was analyzed using a Hitachi S-4800 scanning electron microscope. X-ray diffraction spectra was recorded using a DRON-3 automated diffractometer, using monochromatic CuKα radiation. Capacitance-voltage characteristics were obtained using a B1500A semiconductor analyzer. Dielectric constant and dielectric loss tangent, calculated for capacitance measurements, are changed as follows: for a bias voltage of U = 0 V, the change in ε is 232–214, and tanδ 0.022–0.16, and for a bias voltage of U = 10 V, ε occurs in the range 135–124 and tanδ from 0.02 to 0.1. The obtained frequency dependences of the dielectric constant of BaTiO3 films show a decrease in the dielectric constant in the range of 10 kHz – 2 MHz. It was found that, with a BaTiO3 film thickness of less than 100 nm, a thin-film capacitor with a lower platinum electrode is not always formed, which is probably caused by shunting of the structure.

The binary complex of poly(PEGMA-co-MAA) hydrogel and PLGA nanoparticles as a novel oral drug delivery system for ibuprofen delivery

To improve the bioavailability of ibuprofen (IBU), we developed a novel binary complex of poly(PEGMA-co-MAA) hydrogel and IBU-loaded PLGA nanoparticles (IBU-PLGA NPs@hydrogels) as an oral intestinal targeting drug delivery system (OIDDS). The IBU-loaded PLGA NPs and pH-sensitive hydrogels were obtained via the solvent evaporation method and radical polymerization, respectively. The final OIDDS was obtained by immersing the hydrogel chips in the IBU-loaded PLGA NPs solutions (pH 7.4) for 3 d. The size distribution and morphology of cargo-free NPs were studied by laser granularity analyzer and transmission electron microscope (TEM). The inner structures of the pH-sensitive hydrogel chips were observed with an S-4800 scanning electron microscope (SEM). The distribution states of IBU in the OIDDS were also studied with X-ray diffraction (XRD) and differential scanning calorimetry (DSC). TEM photographs illustrated that the PLGA NPs had a round shape with an average diameter about 100 nm. Fourier transform infrared spectrum (FTIR) confirmed the synthesis of poly(PEGMA-co-MAA) hydrogel. The SEM picture showed that the final hydrogel had 3D net-work structures. Moreover, the poly(PEGMA-co-MAA) hydrogel showed an excellent pH-sensitivity. The XRD and DSC curves suggested that IBU distributed in the OIDDS with an amorphous state. The cumulated release profiles indicated that the final OIDDS could release IBU in alkaline environment (e.g. intestinal tract) at a sustained manner. Therefore, the novel OIDDS could improve the oral bioavailability of IBU, and had a potential application in drug delivery.

Calibration of a scanning electron microscope from two coordinates

Methods for the calibration of a scanning electron microscope (SEM) operating in the secondary slow electron collection mode from two coordinates, using a single certified size, are described. Calibration is performed with a new test object made of silicon with pitch structures consisting of grooves and cross-shaped protrusions. All relief elements have trapezoidal profiles with large inclination angles of the side walls. The planes of the side walls coincide with the crystallographic planes {111} of silicon, and the planes of the top of the protrusions and bottom of the grooves coincide with the crystallographic planes {100}. The certified parameter is the pitch of the pitch structure, equal to 2000 nm. Two methods of SEM calibration are described. The first one employs for calibration the end parts of the pitch structures. It enables one to determine the pixel size from two coordinates; the electron-beam size (effective diameter), from two coordinates; and the nonorthogonality of the beam to the test object plane, from one coordinate. The second method employs for calibration a cross-shaped protrusion. It enables one to determine the pixel size from two coordinates; the electron beam size, from two coordinates; and the nonorthogonality of the beam to the test object plane, from two coordinates. The methods of SEM calibration are tested using an S4800 SEM. The asymmetry (1.5%) of the image, caused by the difference in the pixel sizes in two coordinates, and the asymmetry of the SEM electron beam (about 30%), caused by beam defocusing, are found. The nonorthogonality of the electron beam is less than 1° in both coordinates.

Development and evaluation of a novel polymeric hydrogel of sucrose acrylate-co-polymethylacrylic acid for oral curcumin delivery

A monomer of sucrose acrylate (AC-sucrose) was synthesized by conjugating starting compound sucrose with methyl acrylate (MA). The obtained AC-sucrose was characterized by mass spectrometry (MS) and Fourier transform infrared (FTIR) spectroscopy. AC-sucrose was selected as a monomer to fabricate a novel pH sensitive hydrogel via free radical polymerization. The inner morphology of the final hydrogel was observed with an S-4800 scanning electron microscope (SEM). The swelling and de-swelling behaviors of the hydrogel chips were also studied. Curcumin (CUR) was selected as a model drug and loaded into the final hydrogel. The release profiles of CUR were performed via dialysis method in pH 1.2, 6.8 and 7.4 buffers, respectively. Mass and FTIR spectra confirmed the synthesis of AC-sucrose. SEM photographs showed that poly(AC-sucrose-co-MAA) hydrogels had many 3D meshes. In pH 1.2 buffer, the hydrogel chips showed the biggest swelling ratio (SR) of 34.4 ± 1.9%. However, in pH 7.4 buffer, the SRs of the hydrogel chips reached to 368.7 ± 28.0%, which suggested that the hydrogel had an excellent pH sensibility. The releasing profiles showed that only 4.6 ± 0.4% of CUR was released in pH 1.2 buffer but 93.7 ± 4.7% of CUR was diffused into pH 7.4 buffer. These data suggested that the CUR-loaded poly (AC-sucrose-co-MAA) hydrogel could direct CUR to release in basic environments.

Experimental Research on High Speed Grinding of Silicon Nitride Ceramic Spindle

Grinding is a main method of silicon nitride ceramic in finish machining stage. The technical parameters had an important influence on the surface quality of silicon nitride ceramic. The silicon nitride ceramic spindle was ground by the high-speed cylindrical grinder MGKS1432-H. The relations between different speed parameters and surface roughness were researched. The cylindrical and internal high speed grinding experiments of silicon nitride ceramics spindle were carried out. The S-4800 scanning electron microscope was used to explore the roughness change rule of the grinded surface under the condition of only changed grinding wheel’s velocity. In the process of cylindrical and internal grinding on silicon nitride ceramic spindle, the roughness tended to decrease with the linear velocity increasing, and increased with the radial feed speed increasing and decreased with the wheel shaft’s oscillation speed increasing. The result indicated that the linear velocity of grinding wheel influenced the sample’s roughness most. The effect of radial feed speed on the roughness is next only to the effect from linear velocity. The effect of shaft’s oscillation speed on the roughness is the lowest of the three factors. In the process of internal grinding, with the linear velocity increasing, the ceramic material transformed from brittle rupture to plastic deformation and the roughness appeared one peak. These results were very helpful to optimize the grinding parameters and improve grinding efficiency.

Preparation and characterization of a novel pH-sensitive hydrogel obtained from UV light-induced polymerization

The main aim of this study was to develop a novel pH-sensitive hydrogel prepared via an UV light-induced polymerization. Single-factor experiments were performed to acquire the optimum formula of final poly(MAA-co-PEGMA) hydrogel. Fourier transform infrared spectroscopy (FTIR) spectra were employed to confirm the successful preparation of the designed copolymers. Inner morphologies of the polymeric hydrogels were observed via an S-4800 scanning electron microscope (SEM). Swelling and reversible swelling–shrinking studies were carried out in different phosphate buffer solution (PBS) with various pH values. Drug-loading tests were performed with bovine serum albumin (BSA) as a model drug. The in vitro release profile was also investigated in PBS with the pH values of 1.2 and 7.4. FTIR spectra confirmed the preparation of the poly(MAA-co-PEGMA) copolymers without any residual monomers. The typical space grid structures were observed from the SEM photographs of hydrogels. The obtained hydrogel showed an excellent pH-sensibility and reversible swelling–shrinking property. The maximum drug-loading (40.9 %) was gained from the BSA concentration of 50.0 mg/mL. During the releasing process, only 5.8 ± 0.9 % of BSA was released at pH 1.2, but 82.1 ± 6.2 % was diffused at pH 7.4. These data suggested that such medicated hydrogel could deliver BSA to alkaline conditions (e.g., intestinal environments) site-specifically, which protected BSA from destroying by gastric acid or pepsase. Therefore, such hydrogel had a significant meaning in theoretical research and practical application.

Research and Application of S-4800 Scanning Electron Microscope in Modern Testing and Analysis Technology

Mechanism and functions of S-4800 Scanning Electron Microscope are introduced in this paper. The image-forming mechanism and structure of SEM are studied, and the signal transformation of secondary electron and backscattered electron is presented. The main application fields of SEM are researched.

Electrochemical behaviour in process of electrodeposition Ni–P alloy coating

An Ni–P alloy coating was obtained by electrodeposition on a 45 carbon steel substrate. The surface appearance of the coating was characterised by Hitachi S-4800 scanning electron microscope. The electrodeposition behaviour was investigated using electrochemical methods. The results showed that the Ni–P alloy coating was dense and smooth. The electrodeposition of the Ni–P alloy followed the mechanism of three-dimensional nucleation and subsequent grain growth. The main deposition process changed from heterogeneous nucleation/growth of Ni onto the 45 carbon steel substrate to heterogeneous nucleation/growth of Ni–P onto Ni film. There was low frequency scatter on electrochemical impedance spectroscopy plots, which can be attributed to the production of gas. With increasing negative bias voltage, the low frequency scatter became more obvious, and the charge transfer resistances Rct and Rp increased.

Distortion of the Profile of Surface Relief Elements of Single-Crystal Silicon Caused by Contamination in a Low-Voltage Scanning Electron Microscope

This is a study of the influence of contamination in an S-4800 scanning electron microscope at electron energies of 1 keV on the profile of the surface relief elements of an MShPS-2.0K standard gauge. The observed width of the upper base of the relief elements is found to increase with electron irradiation dose in different irradiation modes.

Pulse Discharge Strengthening of 16Mn Welded Joint and Mechanical Performance

The way of pulse discharge strengthening is introduced, and the electromagnetic heat pulse discharge method can increase the strength and toughness of welded joints. 16Mn low alloy steel welded joints are used in the ZL-2 super pulse current generator, and the test of pulse discharge strengthening is carried out. And the mechanical performance comparison test of welded joint is finished. On the universal tensile machine, tensile strength test before and after strengthening has been done. On the S-4800 scanning electron microscope, micro-fracture morphology is analyzed. The results show that electromagnetic heat strengthening test is carried out based on the appropriate discharge parameters. In the junction of weld and base metal near the heat affected zone of the fracture, there is a white layer organization. It appears to improve the mechanical performance of welded joint, and enhance strength and toughness of welded joints.

Defect of Hepatocyte Growth Factor Activator Inhibitor Type 1/Serine Protease Inhibitor, Kunitz Type 1 (Hai-1/Spint1) Leads to Ichthyosis-Like Condition and Abnormal Hair Development in Mice

Hepatocyte growth factor activator inhibitor type 1 (HAI-1)/serine protease inhibitor, Kunitz type 1 (SPINT1) is a membrane-bound, serine proteinase inhibitor initially identified as an inhibitor of hepatocyte growth factor activator. It also inhibits matriptase and prostasin, both of which are membrane-bound serine proteinases that have critical roles in epidermal differentiation and function. In this study, skin and hair phenotypes of mice lacking the Hai-1/Spint1 gene were characterized. Previously, we reported that the homozygous deletion of Hai-1/Spint1 in mice resulted in embryonic lethality attributable to impaired placental development. To test the role of Hai-1/Spint1 in mice, the placental function of Hai-1/Spint1-mutant mice was rescued. Injection of Hai-1/Spint1(+/+) blastocysts with Hai-1/Spint1(-/-) embryonic stem cells successfully generated high-chimeric Hai-1/Spint1(-/-) embryos (B6Hai-1(-/-High)) with normal placentas. These embryos were delivered without apparent developmental abnormalities, confirming that embryonic lethality of Hai-1/Spint1(-/-) mice was caused by placental dysfunction. However, newborn B6Hai-1(-/-High) mice showed growth retardation and died by 16 days. These mice developed scaly skin because of hyperkeratinization, reminiscent of ichthyosis, and abnormal hair shafts that showed loss of regular cuticular septation. The interfollicular epidermis showed acanthosis with enhanced Akt phosphorylation. Immunoblot analysis revealed altered proteolytic processing of profilaggrin in Hai-1/Spint1-deleted skin with impaired generation of filaggrin monomers. These findings indicate that Hai-1/Spint1 has critical roles in the regulated keratinization of the epidermis and hair development.