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The properties of two-dimensional (2D) materials are highly dependent on their phase and thickness. Various phases exist in tin disulfide (SnS2), resulting in promising electronic and optical properties. Hence, accurately identifying the phase and thickness of SnS2 nanosheets is prior to their optoelectronic applications. Herein, layered 2H-SnS2 and 4H-SnS2 crystals were grown by chemical vapor transportation and the crystalline phase of SnS2 was characterized by X-ray diffraction, ultralow frequency (ULF) Raman spectroscopy and high-resolution transmission electron microscope. As-grown crystals were mechanically exfoliated to single- and few-layer nanosheets, which were investigated by optical microscopy, atomic force microscopy and ULF Raman spectroscopy. Although the 2H-SnS2 and 4H-SnS2 nanosheets have similar optical contrast on SiO2/Si substrates, their ULF Raman spectra obviously show different shear and breathing modes, which are highly dependent on their phases and thicknesses. Interestingly, the SnS2 nanosheets have shown phase-dependent electrical properties. The 4H-SnS2 nanosheet shows a current on/off ratio of 2.58 × 105 and excellent photosensitivity, which are much higher than those of the 2H-SnS2 nanosheet. Our work not only offers an accurate method for identifying single- and few-layer SnS2 nanosheets with different phases, but also paves the way for the application of SnS2 nanosheets in high-performance optoelectronic devices.

Intentional electromagnetic interference is a serious threat to the safety of electronic devices. Multiple electromagnetic pulses will be coupled and transmitted to electronic devices through the cables. Accumulative effects are generated, which make it easier for damage to occur in the electronic devices. In this article, the working principle of micro-silicon acceleration sensors is introduced. The accumulative effects of multiple pulses on acceleration sensors is studied by a large number of injection experiments. The accumulation trends of multiple pulses with different pulse numbers and intervals are analyzed. The damaged structures inside abnormal sensor amplifiers were observed via optical microscopy and scanning electron microscopy. The experimental results show that the accumulative effect is strengthened with increased pulse number or decreased pulse interval, and the threshold voltage for multiple pulses on the acceleration sensor decreases. The threshold voltage for a single pulse is 321.57 V. When the pulse interval is 1 μs and the pulse number is 5, the threshold voltage for multiple pulses is 163.42 V, which is reduced by 49.12% compared with a single pulse. These results provide a reference for the damage design of electromagnetic pulse weapons.

Artists engaging with the nanoscale have a particular problem of representation: Humans are unable to directly perceive nanoscale phenomena. Even without sensory or temporal experience of these phenomena, nanoartists are exploring technological, interactive and audiovisual mediation techniques. The author discusses this “problematic perception,” describes a key piece of nanoscientific instrumentation and finds diverse nanoart practices that exhibit a common concern for multisensoriality and embodied experience. This reflects our human desire to use our bodies to explore the world. Finally the author explores the question: How might nanoscientific and cinematic imaging systems work together with the perceiving body to further facilitate this multisensoriality?

Confocal microscopy1 remains a major workhorse in biomedical optical microscopy owing to its reliability and flexibility in imaging various samples, but suffers from substantial point spread function anisotropy, diffraction-limited resolution, depth-dependent degradation in scattering samples and volumetric bleaching2. Here we address these problems, enhancing confocal microscopy performance from the sub-micrometre to millimetre spatial scale and the millisecond to hour temporal scale, improving both lateral and axial resolution more than twofold while simultaneously reducing phototoxicity. We achieve these gains using an integrated, four-pronged approach: (1) developing compact line scanners that enable sensitive, rapid, diffraction-limited imaging over large areas; (2) combining line-scanning with multiview imaging, developing reconstruction algorithms that improve resolution isotropy and recover signal otherwise lost to scattering; (3) adapting techniques from structured illumination microscopy, achieving super-resolution imaging in densely labelled, thick samples; (4) synergizing deep learning with these advances, further improving imaging speed, resolution and duration. We demonstrate these capabilities on more than 20 distinct fixed and live samples, including protein distributions in single cells; nuclei and developing neurons in Caenorhabditis elegans embryos, larvae and adults; myoblasts in imaginal disks of Drosophila wings; and mouse renal, oesophageal, cardiac and brain tissues. A combination of multiview imaging, structured illumination, reconstruction algorithms and deep-learning predictions realizes spatial- and temporal-resolution improvements in fluorescence microscopy to produce super-resolution images from diffraction-limited input images.

Different types of SPD techniques are applicable and have been studied by various researchers. All of them have several advantages and disadvantages. Equal Channel Angular Pressing (ECAP) is one of the most popular SPD techniques and is still being developed. The aim of this paper is to improve the efficiency of ECAP process by putting forward a novel design (Twisted Variable Channel Angular Pressing (TV-CAP)) and also to achieve higher mechanical properties when compared to conventional ECAP processes. For this purpose, a new TV-CAP die was designed by combining three different methods: ECAP, Twist Extrusion, and Direct Extrusion. The new design was able to integrate the advantages of each method to the workpiece material. In this context, the design parameters of the TV-CAP die were first identified by finite element analysis (FEA) in Deform-3D. The TV-CAP die was produced according to the determined parameters and AA5083 alloy was pressed with this novel die. Hardness and tensile tests were carried out to compare mechanical properties. In addition, Optical Microscope, SEM, TEM images were taken, and XRD and EBSD analyses were carried out to examine the changes in grain structure. As a result of this experimental study, an increase of 197.3% was observed in the hardness value and an increase of 144.7% was achieved in the tensile strength value by using the novel TV-CAP die. These results also agreed with the effective strain values obtained from the FEA.

Image-based qualitative and quantitative structural analyses using high-resolution light microscopy are integral parts of the materialographic work on materials and components. Vibrations or defocusing often result in blurred image areas, especially in large-scale micrographs and at high magnifications. As the robustness of the image-processing analysis methods is highly dependent on the image grade, the image quality directly affects the quantitative structural analysis. We present a deep learning model which, when using appropriate training data, is capable of increasing the image sharpness of light microscope images. We show that a sharpness correction for blurred images can successfully be performed using deep learning, taking the examples of steels with a bainitic microstructure, non-metallic inclusions in the context of steel purity degree analyses, aluminumsilicon cast alloys, sintered magnets, and lithium-ion batteries. We furthermore examine whether geometric accuracy is ensured in the artificially resharpened images.

The Laser-Powder Bed Fusion (L-PBF) based AlSi7Mg parts are adopted for the aerospace industries, especially for making antenna, RF components, gyroscopes, and waveguides. The primary use of additive manufacturing in the aerospace industry is because it enables producing very lightweight components with complex designs. However, the mechanical properties of manufactured L-PBF components are not yet fully validated because numerous challenges posed by the process itself and defects that occur on the manufactured materials by L-PBF. In this research, to further elucidate the printing mechanism of AlSi7Mg lightweight alloy a detailed investigation was carried out to analyze the influence of print orientation on the physical, morphological, and mechanical behavior of L-PBF based AlSi7Mg parts. AlSi7Mg parts were manufactured with various print orientations from vertical, inclined and horizontal. The fabricated parts were analyzed for microstructural behavior using an optical microscope (OM), and scanning electron microscope (SEM) with energy dispersive X-ray analysis (EDAX) proving the elemental composition of the AlSi7Mg parts were studied. Mechanical testing such as tensile, hardness, wear, fracture toughness, and shear tests was carried out for various orientations manufactured in order to evaluate their properties. The vertically-oriented AlSi7Mg parts shows 13.8 %, 58.4 % and 7.9 % higher tensile, toughness and shear strength when compared with the horizontally-oriented parts. But the maximum wear resistance was observed in the horizontal parts and it was 52.9 % higher wear resistance than the vertical parts. The results can be used as a guide in the aerospace industry in order to design components with high structural integrity.

3D printing is a process of creating a three-dimensional solid object of virtually any shape from a digital CAD model which is fast growing from research to production technology. The present study is aimed to develop the fuel injector component using 3D printing technology for missile applications. The primary objective is to demonstrate the potential advantages of 3D printing like reduction in part assembly, elimination expensive EBW for joining, CNC machining and also EDM processes without any compromise in functional performance of the component. The re-design of fuel injector was carried out by adopting a novel design concept by modifying the features of internal chamber, thereby completely avoiding the necessity for support structures in 3D printing. Different design configurations were developed with flow optimisation and topology optimisation for weight reduction, for 3D printing of the component. Initially, a proof of concept model was successfully built in IN718 alloy powder material using PBF-based 3D printing facility at AERDC, HAL. The 3D-printed fuel injector in as-deposited condition was evaluated using X-ray 3D tomography which has revealed well-formed internal features and uniform material density without any macro pores or cracks. XRF confirmed the chemical homogeneity at different locations on 3D-printed component. Microstructural characterisation was carried out using optical microscopy (OM), SEM and EBSD analysis. The OM evaluation indicated presence of micro-porosity (

The article presents studies of the additive manufacturing printing parameters influence onthe impact strength of PLA samples obtained by the fused filament fabrication (FFF) method. Two processvariables were taken into account in the research program: the height of the printed layer andthe printing temperature. An optical microscope was used to analyze the cross-section image (breakthrough)of the samples. The impact strength was determined at −40°C and 23°C. Selected geometricfeatures of the macrostructure (uniformity and thickness of individual layers, voids) determined on thebasis of the sample cross-section image analysis, enhanced the possibility of assessing the PLA impactstrength, depending on the adopted process variables and the temperature at which the experiment wascarried out.

In the present work, we investigated the thin film properties, stability, and surface defects of various compositions of indium gallium zinc oxide (IGZO) and indium zinc oxide (IZO) thin films. The thin films of IGZO and IZO were obtained through the solution processing route and deposited using the spin coating technique. All films were found to be amorphous with roughness below 2.0 nm. Further, it was established that the introduction of gallium helps in controlling the electrical resistivity and stabilizing the amorphous phase of IGZO films. The time-dependent study of IGZO and IZO thin films reveals that the films remain structurally stable for one month. However, a slight change in the morphology can be seen after 13 days. The films which seem to be uniform and smooth under an optical microscope also contain few dark spots as well. These dark spots upon close investigation using atomic force microscopy (AFM) and electron probe microscope analyzer (EPMA) reveal that they are the part of films themselves, stand in a vertical position, and the composition on these spots is high in indium content. Simultaneously, the measured composition of the spot-free surface is always less in indium content in comparison to the expected composition. In this study, our findings predict that in the case of solution-processed IGZO and IZO thin films there is a possibility of movement of indium ions to form a surface defect, which in turn can lead to the poor performance of IGZO and IZO based devices.

We present a new sensing technique, termed photoacoustic radiometry (PAR), for mapping the optical attenuation properties of a sample. In PAR, laser pulses attenuated via transmission through the sample impinge on the ultrasound transducer and generate a photoacoustic (PA) signal within it. Spatial variation of the optical attenuation properties of the sample influences the amplitude of the PAR signal, providing image contrast. Performed simultaneously with pulse-echo ultrasound and PA imaging, this triplex imaging technique enables rapid characterization of samples with micrometer-resolution in a single scan. In this work, we demonstrate that the PAR technique can be easily integrated into existing PA microscopy systems, with applications in imaging biological samples and non-destructive evaluation of optically opaque materials such as silicon wafers.

Perfluorocarbon droplets containing nanoparticles (NPs) have recently been investigated as theranostic and dual-mode contrast agents. These droplets can be vaporized via laser irradiation or used as photoacoustic contrast agents below the vaporization threshold. This study investigates the photoacoustic mechanism of NP-loaded droplets using photoacoustic frequencies between 100 and 1000 MHz, where distinct spectral features are observed that are related to the droplet composition. The measured photoacoustic spectrum from NP-loaded perfluorocarbon droplets was compared to a theoretical model that assumes a homogenous liquid. Good agreement in the location of the spectral features was observed, which suggests the NPs act primarily as optical absorbers to induce thermal expansion of the droplet as a single homogenous object. The NP size and composition do not affect the photoacoustic spectrum; therefore, the photoacoustic signal can be maximized by optimizing the NP optical absorbing properties. To confirm the theoretical parameters in the model, photoacoustic, ultrasonic, and optical methods were used to estimate the droplet diameter. Photoacoustic and ultrasonic methods agreed to within 1.4%, while the optical measurement was 8.5% higher; this difference decreased with increasing droplet size. The small discrepancy may be attributed to the difficulty in observing the small droplets through the partially translucent phantom.

In recent years, the interest in additive manufacturing technologies has increased significantly, most of them using powders as feedstock material. It is therefore essential to check the quality of the powder before processing in order to ensure the same quality of the printed components at all times. This kind of quality assurance of a powder should be carried out independently of the additive manufacturing technology used. Since there is a lack of standards in this field, various powder analysis methods are available, with which, in principle, the same characteristics can often be measured, at least nominally. To verify the validity of these methods, three different nickel-based powders used for additive manufacturing were examined in the present study using standard methods (apparent density, tap density, Hall flow rate, optical microscopy, scanning electron microscopy) and advanced characterization methods (dynamic image analysis, x-ray microcomputed tomography, adsorption measurement by Brunauer–Emmett–Teller method). A special focus has been given on particle size distribution, particle shape, specific surface area, and internal porosity. The results of these measurements were statistically compared. This study therefore provides an insight into the advantages and disadvantages of various optical characterization techniques.

Optically transparent materials are being found in an ever-increasing array of technological applications within industries, such as automotive and communications. These industries are beginning to realize the importance of implementing surface engineering techniques to enhance the surface properties of materials. On account of the importance of surface engineering, this paper details the use of a relatively inexpensive diode-pumped solid state (DPSS) Nd:YVO4 laser to modify the surfaces of fused silica glass, diamond, and sapphire on a micrometre scale. Using threshold fluence analysis, it was identified that, for this particular laser system, the threshold fluence for diamond and sapphire ranged between 10 Jcm−2 and 35 Jcm−2 for a laser wavelength of 355 nm, dependent on the cumulative effects arising from the number of incident pulses. Through optical microscopy and scanning electron microscopy, it was found that the quality of processing resulting from the Nd:YVO4 laser varied with each of the materials. For fused silica glass, considerable cracking and deformation occurred. For sapphire, good quality features were produced, albeit with the formation of debris, indicating the requirement for post-processing to remove the observed debris. The diamond material gave rise to the best quality results, with extremely well defined micrometre features and minimal debris formation, comparative to alternative techniques such as femtosecond laser surface engineering.

The effects of initial oxygen concentration on the reverse leakage current of PIN rectifier diodes were studied. We fabricated the PIN rectifier diodes with different initial oxygen concentrations, and analyzed the electrical properties, anisotropic preferred etching by means of optical microscopy, Fourier transform infrared spectroscopy and transmission electron microscopy. It is pointed out that the reverse leakage current increases exponentially with the increasing initial oxygen concentration. Furtherly, we researched and analyzed the mechanism of the effects of initial oxygen concentration on the reverse leakage current of PIN rectifier diode. It is shown that the oxygen precipitations present in an “S” curve with increasing initial oxygen concentration after high temperature diffusion. The main reason is that the nucleation and growth of oxygen precipitation at high temperature induce bulk oxidation-induced defects (B-OSF), which are mainly dislocations, and a small amount of rod stacking faults. The density of B-OSF increases with the increasing initial oxygen concentration. The existence of B-OSF has great effects on the reverse leakage current of PIN rectifier diode.

A low-cost, lateral off-axis non-IR imaging system is proposed to inspect the melt-pool in the Laser Powder Bed Fusion (L-PBF) processing of IN718 powder and stainless steel 316 L powder. In the proposed system, a perspective transformation method is applied to transform the captured side-view image into a top-view image and the melt-pool boundary is then determined based on an inspection of the gray-level intensity profile of the captured image and its first derivative. For the IN718 L-PBF process, the measurement results obtained for the melt-pool width and melt-pool length vary by no more than 13% and 3%, respectively, from the experimental results reported in the literature. For the SS316L, the measured melt-pool width is within 6% of the ex-situ measurements obtained by optical microscopy, while the melt-pool length differs by no more than 9% from the numerical predictions. Overall, the results show that the proposed system provides a viable means of detecting potential build failures during the L-PBF process and improving the yield of the fabrication process as a result.

In this work, effect of Mo content on the microstructure, thermal conductivity, and corrosion resistance of the die steels was investigated by optical microscopy, scanning electron microscopy, x-ray diffraction, laser thermal conductivity meter, electrochemical experiments, and pitting tests. The microstructure of the die steels is mainly composed of lath-shaped tempered martensite. At all the tested temperatures, the thermal conductivity of the die steels is decreased with the increase in Mo content from 1.2 to 5.0 wt.%. However, electrochemical experiments indicate that increase in Mo content in the die steels can reduce the corrosion current density and increase the charge transfer resistance in 0.5 mol·L−1 HCl solution. Furthermore, it was found that Mo in the die steels is beneficial to decrease weight loss and pitting corrosion rate, which improves the pitting corrosion resistance of the die steels.

In this paper, we demonstrate the fabrication of S-shaped micron-sized constrictions on steel (Fe3CII) surface using the femtosecond laser ablation technique. The femtosecond laser used has a wavelength of 775 nm, a power range of 0–1000 mW, a pulse duration of 130 fs, and a pulse repetition rate of 1–2 kHz. The ultra-low-pulse duration of 130 fs enables ablation of material surfaces without excessive thermal heating of the material around the zone of ablation. This becomes useful when ablating materials that are thermally sensitive such as superconducting thin films. This practice run of ablating S-shaped micron-sized constrictions on steel surfaces shown in this paper will enable one to use the same technique in ablating micron- and nano-sized structures on superconducting thin films without thermally altering the superconductive film. In this paper, S-shaped micron-sized constrictions on steel were fabricated with a constriction width of 37.1 and 47.3 μm whose images were created using an optical microscope (OM) and S-shaped micron-sized constrictions with a constriction width of 30.8 and 35.2 μm whose images were created using an atomic force microscope (AFM). The reduction in the constriction widths was achieved by reducing the laser ablation width or laser ablation spot size and then bringing the laser ablation spots closer together in G-code program. The reduction of the laser ablation width is achieved by reducing the laser fluence applied closer to the ablation threshold of steel and by using laser beam shaping techniques such as beam collimation and beam focusing.

The development of appropriate methods to correlate the structure and optical properties of colloidal photonic structures is still a challenge. Structural information is mostly obtained by electron, X-ray, or optical microscopy methods and X-ray diffraction, while bulk spectroscopic methods and low resolution bright-field microscopy are used for optical characterization. Here, we describe the use of reflectance confocal microscopy as a simple and intuitive technique to provide a direct correlation between the ordered/disordered structural morphology of colloidal crystals and glasses, and their corresponding optical properties.

Multimodal optical microscopy combines different optical and physiological principles working together to obtain rich perspectives from a single biological event. In this paper, the recent advances in multimodal microscopy systems based on off-axis digital holography and transport-of-intensity equation are reviewed. Both methods used the common-path configuration, and realized simultaneous quantitative phase and fluorescence imaging in 3D space. Feasibility checks with fluorescent micro-beads and live plant cells are presented. The results show that both methods are capable of fast acquisition of the quantitative phase and fluorescence information with digital refocusing ability.

An image distortion elimination method based on optimized windowed Fourier transform processing is proposed in this paper. Simulation testing was performed beforehand to find the optimal window size and grating pitch (in pixels), which are crucial for the distortion calibration accuracy. With the optimized parameters, gratings with different frequencies were fabricated by photolithography as standard plates to calibrate the aberration of the optical microscope. The influence induced by the misalignment of the grating lines and the viewing field axis on the distortion calibration was addressed and eliminated by the proposed method in this paper. With the proposed method, the image distortion of the optical microscope under various magnifications was calibrated successfully.

The paper presents two methods for identifying microstructural heterogeneities on the surface of OFAM-K and OPMN-P nanofiltration membranes. Optical microscopy in combination with the AutoCad 2016 computer-aided design system and standard Microsoft Excel 2010 tools allows one to investigate microstructural heterogeneities of initial samples of OPMN-P and OFAM-K nanofiltration membranes. A method that enables the automated calculation of the average diameter of the fouling of semi-permeable membranes and the fouling coefficient of porous bodies is also developed. Using the capabilities of the Matlab 2017 software package, the application of modern tools to accomplish the set goal of the work is shown. Practical implementation of the method is exemplified by the nanofiltration process with semi-permeable polymer membranes of OFAM-K and OPMN-P types. The automated method combining optical microscopy studies, Otsu image processing, and software implementation in Matlab 2017 and optical microscopy in combination with the AutoCad 2016 computer-aided design system and standard Microsoft Excel 2010 tools, which more accurately reveals the structural heterogeneities of OFAM-K and OPMN-P nanofiltration membranes, are compared.

The focused ion beam treatment of substrates with transparent electrodes coated with rubbed polymer layers is a key step in creating liquid crystal metasurfaces. This treatment provides local control over the liquid crystal alignment near the substrate surface. The structure, composition, and optical properties of the FIB-treated substrate surface were studied by the scanning electron microscopy, transmission electron microscopy (TEM), atomic force microscopy, optical microscopy, and Auger electron spectroscopy. The effects of rubbing and ion-beam irradiation are analyzed to elucidate the microscopic features and the reasons for changes in aligning properties.

The growth of wide-bandgap materials on patterned substrates has revolutionized the means with which we can improve the light output power of gallium nitride (GaN) light-emitting diodes (LEDs). Conventional patterned structure inspection usually relies on an expensive vacuum-system-required scanning electron microscope (SEM) or optical microscope (OM) with bulky objectives. On the other hand, ultra-thin metasurfaces have been widely used in widespread applications, especially for converging lenses. In this study, we propose newly developed, highly efficient hexagon-resonated elements (HREs) combined with gingerly selected subwavelength periods of the elements for the construction of polarization-insensitive metalenses of high performance. Also, the well-developed fabrication techniques have been employed to realize the high-aspect-ratio metalenses working at three distinct wavelengths of 405, 532, and 633 nm with respective diffraction-limited focusing efficiencies of 93%, 86%, and 92%. The 1951 United States Air Force (USAF) test chart has been chosen to characterize the imaging capability. All of the images formed by the 405-nm-designed metalens show exceptional clear line features, and the smallest resolvable features are lines with widths of 870 nm. To perform the inspection capacity for patterned substrates, for the proof of concept, a commercially available patterned sapphire substrate (PSS) for the growth of the GaN LEDs has been opted and carefully examined by the high-resolution SEM system. With the appropriately chosen metalenses at the desired wavelength, the summits of structures in the PSS can be clearly observed in the images. The PSS imaging qualities taken by the ultra-thin and light-weight metalenses with a numerical aperture (NA) of 0.3 are comparable to those seen by an objective with the NA of 0.4. This work can pioneer semiconductor manufacturing to choose the polarization-insensitive GaN metalenses to inspect the patterned structures instead of using the SEM or the bulky and heavy conventional objectives.

We report on the synthesis and characterization of an amorphous zirconium oxide (a-ZrOx) thin film as an anti-reflective coating (ARC) for a silicon solar cell. In this work, a low-temperature non-vacuum sol–gel spin-coating method was used to synthesize a-ZrOx at room temperature by dispersing zirconium(IV) acetylacetonate in washing grade ethanol as a solvent. The formation of a-ZrOx complex by UV exposure was intended for potential PV applications. The optical and electronic properties of the synthesized a-ZrOx were characterized by EDAX, FESEM, optical microscopy, FTIR, spectroscopic ellipsometry, UV–visible spectroscopy, AFM, TEM, photoluminescence, I–V measurement, quantum efficiency measurement system, etc. The impact of increased UV exposure on the synthesized film revealed the suitability of amorphous structure for photovoltaic applications. The variation in photovoltaic properties, refractive index (1.4–1.76) at wavelength of 632 nm and roughness ~ (296 pm–720 pm) is attributed to the disparity in structural properties of the film. The use of a-ZrOx as an ARC resulted in improved short-circuit current density (Jsc), open-circuit voltage (Voc) and fill factor (FF) which led to the enhanced efficiency from 7.30% to 9.56%. The quantum efficiency measurements showed the pinholes both in the device fabrication and the spin-coated zirconium oxide.

Various methods could be employed to synthesize nanomaterials. In this work laser induced forward technology was used to synthesize silver nanoparticles. Silver nanomaterials were tested using different measuring instruments such as UV–vis diffuse (DRS), Atomic Force Microscopy (AFM), and optical Microscope to characterize features such as the optical and morphological properties of these nanoparticles. AFM results show that when the laser energy of the pulsed Nd: YAG laser increases, the diameter and roughness of produced AgNPs will be decreased for the same number of pulses and the air cavity between donner and acceptor. Also, results show that when laser energy is (300,400) mJ, the AgNPs diameters are (95.76,88.44) nm and the roughness are (7,6) nm respectively. While, results show that as laser pulses increase, structure to be rougher for different laser pulses and constant laser energy at 300 mJ the same behavior will be found when the laser energy becomes 400mJ.Finally, results show that the reflectance peaks of Ag NPs increase by decreasing the number of pulses to a maximum value of 467 at 2 pulses.

Nowadays, to enhance structural efficiency, ultrasonic vibrations are combined with other manufacturing processes such as welding. It gives considerable advantages in terms of improved mechanical properties, adequate surface strength, improved material flow and uniform grain growth, etc. Welding of 6061-T6 alloy with 6082-T6 aluminium alloys is carried out with dissimilar thickness. Ultrasonic-assisted cold metal transfer (U-CMT) welding is performed to fabricate the joints and improvements in mechanical properties and microstructural modifications are studied. The microstructural analysis is done with the assistance of an optical microscope (OM) and field emission scanning electron microscope (FESEM). The non-destructive technique (NDT) such as the radiography technique (RT) is used to test weld consistency. Results revealed that the weld bead dimensions are increased with the aid of ultrasonic vibrations for the same welding parameters. The tensile strength and microhardness are enhanced. Samples with ultrasonic vibration experience grain refining as compared to those without vibration samples. As compared with CMT, U-CMT is rich in Al-Si eutectic structure which is in globular form, reduces the porosity level.

Growing demands for comprehending complicated nano-scale phenomena in atomic resolution has attracted in-situ transmission electron microscopy (TEM) techniques for understanding their dynamics. However, simple to safe TEM sample preparation for in-situ observation has been limited. Here, we suggested the optical microscopy based micro-manipulating system for transferring TEM samples. By adopting our manipulator system, several types of samples from nano-wires to plate-like thin samples were transferred on micro-electro mechanical systems (MEMS) chip in a single step. Furthermore, the control of electrostatic force between the sample and the probe tip is found to be a key role in transferring process.

High-energy diffraction microscopy (HEDM) in-situ mechanical testing experiments offer unique insight into the evolving deformation state within polycrystalline materials. These experiments rely on a sophisticated analysis of the diffraction data to instantiate a 3D reconstruction of grains and other microstructural features associated with the test volume. For microstructures of engineering alloys that are highly twinned and contain numerous features around the estimated spatial resolution of HEDM reconstructions, the accuracy of the reconstructed microstructure is not known. In this study, we address this uncertainty by characterizing the same HEDM sample volume using destructive serial sectioning (SS) that has higher spatial resolution. The SS experiment was performed on an Inconel 625 alloy sample that had undergone HEDM in-situ mechanical testing to a small amount of plastic strain (~ 0.7%), which was part of the Air Force Research Laboratory Additive Manufacturing (AM) Modeling Series. A custom-built automated multi-modal SS system was used to characterize the entire test volume, with a spatial resolution of approximately 1 µm. Epi-illumination optical microscopy images, backscattered electron images, and electron backscattered diffraction maps were collected on every section. All three data modes were utilized and custom data fusion protocols were developed for 3D reconstruction of the test volume. The grain data were homogenized and downsampled to 2 µm as input for Challenge 4 of the AM Modeling Series, which is available at the Materials Data Facility repository.

In this work, the polarized beams tightly focused through a cylindrical refractive-indices discontinuous dielectric interface was numerically investigated. The corresponding focal pattern calculation formula was deduced base on vectoral diffraction integration theory for the first time. The patterns through the cylindrical dielectric interface with different radii were revealed by numerical calculating and discussed in detail. In addition, the aberration factor of the integration formula was found out, and the phase compensation maps were successfully carried out for focal patterns correcting. The findings will be helpful to improve the spatial resolution of advanced optical microscope in probing samples encapsulated by micro pipes.

Based on previous reports on the optical microscopy contrast of mechanically exfoliated few layer CrCl 3 transferred on 285 nm and 270 nm SiO 2 on Si(100), we focus on the experimental determination of an effective mean complex refractive index via a fitting analysis based on the Fresnel equations formalism. Accordingly, the layer and wavelength-dependent absorbance and reflectance are calculated. Layer and wavelength-dependent optical contrast curves are then evaluated demonstrating that the contrast is significantly high only around well-defined wavelength bands. This is validated a posteriori, by experimental UV-Vis absorbance data. The present study aims to show the way towards the most reliable determination of thickness of the 2D material flakes during exfoliation.

BACKGROUND Semen analysis is an integral part of work up for infertility in men, with sperm morphology being an important qualitative parameter. Qualitative defects can affect any part of the sperm and are classified as defects in the head, middle piece, and tail, based on morphology. The focus of the study was to assess qualitative defects in sperms by light microscopy, in semen with normal sperm counts. METHODS This study is hospital based, descriptive, retrospective study. Of the semen samples received in the clinical laboratory, fifty with normal sperm counts were included in the study and processed according to standard protocol. For evaluation of qualitative defects by sperm morphology, smears were fixed in ethanol, stained with Papanicolaou stain [PAP], and assessed under light microscope. RESULTS The 50 semen samples included in the study had sperm counts ranging from 15 to 80 million / ml. Thirty samples had less than 10 % abnormal forms, fourteen samples had 11 - 20 % abnormal forms, five samples had 21 - 30 % abnormal forms and one sample had 40 % abnormal sperms. Qualitative defects were classified as morphological abnormalities in head, neck, and tail. Of the fifty cases, most defects were found in the head, followed by those in the neck and tail. Common defects noted were double head (44 %), abnormal sized heads, and bent neck (48 %). Coiling was a common defect noted in the tail (10 %). Most sperms showed a combination of defects. CONCLUSIONS Qualitative defects in sperm morphology are often seen in samples with normal sperm counts. Assessment of microscopic characteristics of human spermatozoa is as important as count and motility in the complete evaluation and work-up of semen samples in cases of infertility. KEY WORDS Semen, Sperm, Quality, Microscopy, Morphology

Far-field super-resolution optical microscopies have achieved incredible success in life science for visualization of vital nanostructures organized in single cells. However, such resolution power has been much less extended to material science for inspection of human-made ultrafine nanostructures, simply because the current super-resolution optical microscopies modalities are rarely applicable to nonfluorescent samples or unlabeled systems. Here, we report an antiphase demodulation pump-probe (DPP) super-resolution microscope for direct optical inspection of integrated circuits (ICs) with a lateral resolution down to 60 nm. Because of the strong pump-probe (PP) signal from copper, we performed label-free super-resolution imaging of multilayered copper interconnects on a small central processing unit (CPU) chip. The label-free super-resolution DPP optical microscopy opens possibilities for easy, fast, and large-scale electronic inspection in the whole pipeline chain for designing and manufacturing ICs.

The effect of La on inclusions and fracture toughness of 40CrNi2Si2MoVA steel was investigated via the optical microscope, scanning electron microscope, image software and electronic universal testing machine. The results reveal that the inclusions in steel without La are mainly MnS and Al2O3–MnS, while the inclusions in steels with La primarily contain La–O–S, La–S and other rare earth complex inclusions contain P and As. La–O–S and La–S are formed under the steelmaking temperature and act as the nucleation core of rare earth complex inclusions containing P and As. According to the segregation model, La–O–S–P–As and La–S–P–As are formed through chemical reactions during the solidification stage. As La content in steels increases from 0 to 0.032 mass%, the average spacing of inclusions is gradually increased from 5.28 to 15.91 μm. The volume fraction of inclusions in steels containing less than 0.018 mass% La approaches 0.006%; however, it is significantly improved to 0.058% when La content is increased to 0.032 mass%. With the increase in La content, the fracture toughness is firstly improved from 63.1 to 80.0 MPa m1/2 due to the increase in average spacing of inclusions and then decreases to 69.6 MPa m1/2 owing to the excessive increase in volume fraction of inclusions. The optimal fracture toughness is found in 40CrNi2Si2MoVA steel with 0.018 mass% La.

This study proposed deep learning-based ultrasonic nondestructive testing for porosity evaluation of additively manufactured components. First, porosity mechanisms according to additive manufacturing (AM) processing conditions were studied using traditional scanning acoustic microscopy and optical microscopy. Second, correlations between ultrasonic properties and porosity content were analyzed. The correlation results showed that the increased porosity content resulted in a decreased ultrasonic velocity and increased ultrasonic attenuation coefficient. Third, various levels of porosities were evaluated using a deep learning model based on a fully connected deep neural network that was trained on raw ultrasonic signals measured in the AM samples. After training, the testing performance of the trained model was evaluated. Additionally, the generalization performance of the pre-trained model was assessed using newly fabricated AM samples that were not used for training. The results showed that the porosity content evaluated by the pre-trained model matched well with that measured via traditional scanning acoustic microscopy, thus demonstrating the feasibility of deep learning-based ultrasonic nondestructive testing for porosity evaluation of additively manufactured components.

Six-inch AlInP/GaAs epitaxial wafers grown by organometallic vapor-phase epitaxy (OMVPE) are being developed for light-emitting diodes (LEDs). The surface morphology of the epilayer changes under different growth conditions, where hazy features arise under high growth pressure, preventing their use in device fabricatiion. Applying optical microscopy, atomic force microscopy (AFM), and synchrotron x-ray topography, it is observed that the hazy region is rougher than the clear region and additional lattice distortion exists in the hazy region. The tilt and strain are quantitatively analyzed using 004 reciprocal-space mapping (RSM), where the hazy regions are associated with weakened and broadened peaks surrounding the sharp peak from the clear regions of the epilayer. More importantly, by employing 002 RSM to lower the x-ray penetration depth, it is revealed that the hazy features are formed when a certain thickness is exceeded, indicating that the epilayers do not suffer from lattice distortion at the beginning of the epitaxial growth. The characterization results suggest that changes in the growth conditions at the epilayer–substrate interface may not help to avoid the formation of the hazy features, but that other growth parameters at the bulk epilayer are worth investigation.

In this paper, we report the direct visualization of heat trapping in the pores of a three-dimensional bi-continuous nanoporous graphene film and its application to a self-standing, bendable broadband terahertz (THz) and infrared (IR) detector. Utilizing a scattering-type scanning near-field optical microscope in the mid-IR region, we directly visualized that IR-induced heat is localized in the vicinities of the material nanopores. Nanoscale images of the IR amplitudes also revealed that this heat localization effect became stronger with decreasing pore diameter, and this behavior is consistent with the pore-size dependence of the global thermal conductivity and light reflection. We also found that this material exhibits a high THz and IR absorption rate (>99%), while retaining the Dirac properties of single-layer graphene; on the other hand, conventional graphene loses such properties with increasing number of layers. These unique features enabled us to develop a highly sensitive, bendable THz and IR detector with low thermal conductivity due to heat localization in the vicinities of the nanopores, bendability, and high thermopower using a p-n junction. Thus, through controlled heat conduction by the appropriate design of pore structures, this nanoporous graphene could be applied in wearable thermal devices of broadband energy harvesters and detectors.

Structured illumination microscopy (SIM) is one of the most powerful and versatile super-resolution methods due to its live-cell imaging ability of subcellular structures with high speed. In this paper, we propose an alternative SIM assisted by Bloch surface wave (BSW). Through replacing the conventional laser interference fringes with sub-diffraction BSW counterparts with higher spatial frequency, the imaging resolution of SIM could be enhanced greatly and the super-resolution imaging capability down to 80 nm could be achieved. Compared with traditional wide-field fluorescence microscopy, this BSW SIM demonstrates 2.78 times enhancement in imaging resolution, which surpasses general SIM with only 2 times improvement. Moreover, the structured illumination intensity could be boosted drastically, which is beneficial to nonlinear super-resolution imaging techniques, such as saturated SIM. This BSW SIM would provide a super-resolution, wide field of view approach for surface super-resolution fluorescent imaging while maintaining high imaging speed and good bio-compatibility.

Understanding the mechanical behaviors of granite after thermal treatment under loading and unloading conditions is of utmost relevance to deep geothermal energy recovery. In the present study, a series of loading and unloading triaxial compression tests (20, 40 and 60 MPa) on granite specimens after exposure to different temperatures (20, 200, 300, 400, 500 and 600 °C) was carried out to quantify the combined effects of thermal treatment and loading/unloading stress conditions on granite strength and deformation. Changes in the microstructure of granite exposed to high temperatures were revealed by optical microscopy. The experimental results indicate that both, thermal treatment and loading/unloading stress conditions, degrade the mechanical behaviors and further decrease the carrying capacity of granite. The gradual degradation of the mechanical characteristics of granite after thermal treatment is mainly associated with the evolution of thermal micro-cracks based on optical microscopy observations. The unloading stress state induces the extension of tension cracks parallel to the axial direction, and thus, the mechanical properties are degraded. Temperatures above 400 °C have a more significant influence on the mechanical characteristics of granite than the unloading treatment, whereby 400 °C can be treated as a threshold temperature for the delineation of significant deterioration. This study is expected to support feasibility and risk assessments by means of providing data for analytical calculations and numerical simulations on granite exposed to high temperatures during geothermal energy extraction.

In this study, the (FeMnCrNiCo + 20%TiC) laser cladding layer was re-treated through multiple-pass in-situ laser remelting. Optical microscopy, scanning electron microscopy, and X-ray diffraction w...

The CytoViva Enhanced Darkfield (EDF) Illuminator enables direct optical observation of nano-scale entities in a wide range of transparent and translucent sample environments, without requiring the use of labels or other markers. The improved performance is a result of a uniquely designed light path, which focuses maximum photon density on the sample, thus enabling superior signal-to-noise imaging performance. This high-performance capability not only provides users with previously unobtainable images, but it also allows established techniques such as hyperspectral and Raman microscopy to be used in new and exciting ways.

Optical microscopes are typically designed as versatile tools that are capable of imaging at various modalities with different resolutions in respective visual fields. A large extend of versatility causes increased complexity, size, and the cost. Imaging of tissue sections is a routine procedure in clinics and research laboratories. Tissue staining consumables, required time for staining along with the cost of the imaging systems are the limiting factors for widespread use. A multimode imaging system with enhanced resolution performance and automation is generally superfluous for the coarse resolution imaging of tissue sections. A dedicated system for label free tissue section imaging is presented. Label free imaging with high contrast is provided in form of quantitative phase. Earlier demonstrations of quantitative phase imaging of tissue sections utilized modified microscopes with different modalities for correlated imaging and motorized stages for field enlargement. Here, the system follows an off axis digital holographic imaging configuration for the acquisition of quantitative phase at single shot. The system compromises from the resolution and magnification of a traditional microscope for the size of visual field, ease of use, and relative cost due to the exclusion of sample stages. A software level stitching further enlarges the effective field of view.

The present work deals with the concept of application of ECAP onto commercial Cu-30Zn brass alloy in order to develop the microstructure, mechanical and wear properties. In this regard, specific die for ECAP process with constant parameters has been developed to severely deform brass alloy at room temperature using three passes with route C and lubricating conditions. The microstructure of as-received and ECAP-deformed brass alloy samples were characterized using optical microscope. Micro-hardness and tensile tests were carried out to estimate the mechanical properties of as-received and ECAP processed brass alloy sample. Furthermore, the wear characteristics of investigated brass alloy samples were analyzed using dry sliding wear test at room temperature. The results showed that a significant grain refinement in the microstructure of ECAP deformed brass samples was achieved compared to initial brass alloy. The micro-hardness and mechanical tensile strength were also increased markedly after ECAP process compared to initial brass alloy. Moreover, the wear resistance of ECAP processed brass sample increased significantly after three passes of ECAP compared to initial brass alloy.

This paper shows a non-destructive visualization of the absorption of microwave filed by a graphite periodic structure. The visualization system was a thermo-elastic optical indicator microscope. The article presents the interaction of the electromagnetic field with graphite cylindrical cells of periodicity and shows the distribution of the electromagnetic field over the graphite cells. Depending on the distance between the periodic structure of graphite and the microwave source, the electromagnetic field distribution and absorption rate were different. The visualization was performed using a microwave signal with a frequency of $11~GHz$ and a maximum power of $35~dBm$.

Documenting an object seen in a light microscope is a challenge, especially in limited setting area, for an example when doing field trip for environmental sampling. Taking photographs directly using smartphone, or so called microscopic photography, is not easy. Here we proposed a simple, fast and reliable method of taking photograph with small sized cello tape assisted smartphone on light microscope. We named this procedure “the Urip Susiantoro approach”, methods can be practiced in limited resources setting.