Effects of Pretreatment Processes on Grain Size and Wear Resistance of Laser-Induction Hybrid Phase Transformation Hardened Layer of 42CrMo Steel.

To address the issue of surface grain coarsening in laser-induction hybrid phase transformation of 42CrMo steel, this study investigated the effects of four pretreatment processes (quenching-tempering (QT), laser-induction quenching (LIQ), laser-induction normalizing (LIN), and laser-induction annealing (LIA)) on the austenite grain size and wear resistance after laser-induction hybrid phase transformation. The results showed that QT resulted in a tempered sorbite structure, resulting in coarse austenite grains (139.8 μm) due to sparse nucleation sites.

Chemical-Resistant, Highly-Impermeable Integration of Large Differential Semiconductor and Oxide by Spatial-Confined Plasma Assisted Ultrafast Laser Microwelding for Optofluidic Microsystem.

Large-differential semiconductor and oxide interconnect are widely used in high-performance multi-function integrated microsystems. In this work, spatial-confined plasma-assisted ultrafast laser microwelding has been developed to activate the inert surface and improve mass transportation for robust semiconductor-oxide integration. The inherent stress concentration within the weld of semiconductor (Si) and oxide (Sapphire) can be compensated by inserting hundreds-of-nanometer-thick intermediate oxide layer (SiO).

Strain-Controlled Silicon Patterning on Sapphire Wafer by Ultrafast Laser-Induced Backward Transfer.

Strain engineering of patterned silicon on a sapphire wafer is achieved by modulating the spatial confined plasma during ultrafast laser-induced backward transfer. High-energy laser-ablated silicon plasma can be generated within the confined space, where a transitional SiO layer is formed in the silicon-sapphire interface. Heat transfer to sapphire can thus be hindered, which is beneficial for thermal accumulation in silicon and crystallinity improvement.

Femtosecond Laser Opening Hierarchical Lamination: Micro-Nano Hybrid Scissoring of Three-Dimensional Nitrogen-Doped Graphene for Solar Steam Generation.

Three-dimensional (3D) nanoporous nitrogen-doped graphene is an ideal candidate for solar steam generation. However, the outermost dense layer formed during high-temperature thermal chemical vapor deposition (CVD) severely blocks water transport and steam escape. In this work, a technique of femtosecond laser opening hierarchical lamination (FLOHL) enabling hierarchical micro-nano hybrid scissoring of graphene is presented for its structural and performance upgrades.

Ultrafast Laser-Induced Thickness-Limited Sintering of Metal Nanoparticle Film for Ultrathin Flexible Microelectronic Devices.

Laser sintering of metal nanoparticles (NPs) has been widely used in flexible microelectronic device fabrication, wherein the sintered layer thickness is a key factor affecting the mechanical stability and conductivity. In this work, ultrathin flexible electronic circuits on flexible substrates with robust bonds and excellent conductivity have been fabricated through ultrafast laser-induced thickness-limited sintering of the metal NP film. When the laser fluence is below the damage threshold of the metal NP film, sintered layer thickness can be controlled by the laser parameters.

Thermally Stable Oxide-Capsulated Metal Nanoparticles Structure for Strong Metal-Support Interaction via Ultrafast Laser Plasmonic Nanowelding.

Strong metal-support interaction (SMSI) has drawn much attention in heterogeneous catalysts due to its stable and excellent catalytic efficiency. However, construction of high-performance oxide-capsulated metal nanostructures meets great challenge in materials thermodynamic compatibility. In this work, dynamically controlled formation of oxide-capsulated metal nanoparticles (NPs) structures is demonstrated by ultrafast laser plasmonic nanowelding.

Compositions and Microstructures of Carbonated Geopolymers with Different Precursors.

It is thought that geopolymers are easy to carbonate, especially when they are cured in ambient temperatures. Matrix gel's composition and microstructure, and new products of geopolymers (GPs) after carbonation were investigated in this study on the basis of XRD and SEM-EDS measurements and ternary diagram analysis, which were prepared from low-lime fly ash (FA) and ground granulated blast-furnace slag (GGBS) alone or a blend, as a precursor. The specimens were hardened in a 20 °C environment with alkali activator solution (S/N = 1.

Metal Nanoparticles Assisted Ultrafast Laser Plasmonic Microwelding of Oxide-Semiconductor Interconnects.

Integration of wafer-scale oxide and semiconductor materials meets the difficulties of residual stress and materials incompatibility. In this work, Ag NPs thin film is contributed as an energy confinement layer between oxide (Sapphire) and semiconductor (Si) wafers to localize the materials interaction during ultrafast laser irradiation. Due to the plasmonic effects generated within constructed dielectric-metal-dielectric structures (i.

Influencing Factors of Sulfuric Acid Resistance of Ca-Rich Alkali-Activated Materials.

In this paper, we distinguished the degradation of alkali-activated material (AAM) exposed to sulfuric acid as physical (scaling, spalling, cracking, breaking, etc.) and chemical degradation (neutralization), because the mechanisms of these two types of degradation are different. Then, the effects of curing method, raw materials, and their mixing proportions on the two kinds of degradation of AAMs containing GGBFS were investigated in detail, including liquid-filler ratio, component of alkali activator, chemical admixture, inactive filler alternative to fly ash (FA), addition of municipal waste incineration bottom ash (BA), etc.

Recognitions of colored fabrics/laser-patterned metals based on photothermoelectric effects.

Color is the mapping of electromagnetic waves of different wavelengths in human vision. The electronic color recognition system currently in use is mainly based on the photoelectric effect. Here, we demonstrate a color materials' recognition system based on photothermoelectric effects.

Hierarchical WO Ultrabroadband Absorbers and Photothermal Converters Grown from Femtosecond Laser-Induced Periodic Surface Structures.

Oxygen-vacancy-rich WO absorbers are gaining increasing attention because of their extensive absorbance-based applications in near-infrared shielding, photocatalysis, sterilization, interfacial evaporator and electrochromic, photochromic, and photothermal fields. Thermal treatment in an oxygen-deficient atmosphere enables us to prepare WO but lacks the capacity for finely manipulating the grown structures. In this work, we present that laser-induced periodic surface structure (LIPSS) obtained by femtosecond laser ablation is a good template to grow various hierarchical WO ultrabroadband absorbers and photothermal converters by thermal oxidation annealing in air.

The Effects of Micro-Segregation on Isothermal Transformed Nano Bainitic Microstructure and Mechanical Properties in Laser Cladded Coatings.

The design of metastable retained austenite is the key issue to obtain nano bainitic steel with high strength and toughness. In this study, nanostructured Fe-based bainitic coatings were fabricated using laser cladding and following isothermal heat treatment. The microstructures and mechanical properties of the laser cladded coating were investigated.

Treatment Technology of Hazardous Water Contaminated with Radioisotopes with Paper Sludge Ash-Based Geopolymer-Stabilization of Immobilization of Strontium and Cesium by Mixing Seawater.

Long-term immobilization ratios of strontium (Sr) and cesium (Cs⁺) in paper sludge ash-based geopolymer (PS-GP) were investigated in one year. PS-GP paste specimens were prepared in the conditions of 20 °C and 100% R.H.

Development of Paper Sludge Ash-Based Geopolymer and Application to Treatment of Hazardous Water Contaminated with Radioisotopes.

Ambient temperature geopolymerization of paper sludge ashes (PS-ashes) discharged from paper mills was studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), induction coupled plasma atomic emission spectrometry (ICP-AES), and X-ray absorption near edge structure (XANES). Two varieties of alkaline liquors were used in the PS-ash based geopolymers, corresponding to aqueous Na-metasilicate and Na-disilicate compositions. PS-ashes were found to be semi-crystalline and to have porous structures that make it possible to absorb much liquor.

Effect of Isothermal Temperature on Growth Behavior of Nanostructured Bainite in Laser Cladded Coatings.

The growth and propagation behavior of austenite-to-bainite isothermal transformation in laser-cladded, Si-rich, and Fe-based coatings is investigated. The crystallographic features, orientation relationship at different isothermal temperatures, and the morphology of the nanostructured bainite are determined. The Nishiyama-Wassermann type orientation relationship is observed at a high temperature and at a low temperature, and mixed Nishiyama-Wassermann and Kurdjumov-Sach mechanisms are seen.

Microstructural evolution and mechanical property of Ti-6Al-4V wall deposited by continuous plasma arc additive manufacturing without post heat treatment.

Plasma arc additive manufacturing (PAM) is a novel additive manufacturing (AM) technology due to its big potential in improving efficiency, convenience and being cost-savings compared to other AM processes of high energy bea\m. In this research, several Ti-6Al-4V thin walls were deposited by optimized weld wire-feed continuous PAM process (CPAM), in which the heat input was gradually decreased layer by layer. The deposited thin wall consisted of various morphologies, which includes epitaxial growth of prior β grains, horizontal layer bands, martensite and basket weave microstructure, that depends on the heat input, multiple thermal cycles and gradual cooling rate in the deposition process.

[A primary study on simulation of fracture strength based on BP neural networks].

Objective: To model the relationship between stimulating stress and fracture strength using BP neural networks, and to provide a theoretical basis for accurate prediction of the rate of fracture healing.

Methods: The bilateral tibiae in New Zealand rabbits were osteotomized and fixed by stress-relaxation plate(SRP) and rigid plate(RP), respectively. The stress shielding rate and bending strength of the healing fractures were measured at 2 to 48 weeks postoperatively.

A first order system model of fracture healing.

A first order system model is proposed for simulating the influence of stress stimulation on fracture strength during fracture healing. To validate the model, the diaphyses of bilateral tibiae in 70 New Zealand rabbits were osteotomized and fixed with rigid plates and stress-relaxation plates, respectively. Stress shielding rate and ultimate bending strength of the healing bone were measured at 2 to 48 weeks postoperatively.

[Unequal interval jump grey modeling and its application to the spectral analysis of lubricating oil].

Unequal interval jump grey model was built for raw data series with unequal interval and jump trend in this paper. Levenberg-Marquardt arithmetic that belongs to non-linear least-square. estimation was used to recognize the parameters.

Organ distribution of severe acute respiratory syndrome (SARS) associated coronavirus (SARS-CoV) in SARS patients: implications for pathogenesis and virus transmission pathways.

We previously identified the major pathological changes in the respiratory and immune systems of patients who died of severe acute respiratory syndrome (SARS) but gained little information on the organ distribution of SARS-associated coronavirus (SARS-CoV). In the present study, we used a murine monoclonal antibody specific for SARS-CoV nucleoprotein, and probes specific for a SARS-CoV RNA polymerase gene fragment, for immunohistochemistry and in situ hybridization, respectively, to detect SARS-CoV systematically in tissues from patients who died of SARS. SARS-CoV was found in lung, trachea/bronchus, stomach, small intestine, distal convoluted renal tubule, sweat gland, parathyroid, pituitary, pancreas, adrenal gland, liver and cerebrum, but was not detected in oesophagus, spleen, lymph node, bone marrow, heart, aorta, cerebellum, thyroid, testis, ovary, uterus or muscle.

[Expression of the monoclonal antibody against nucleocapsid antigen of SARS-associated coronavirus in autopsy tissues from SARS patients].

Objective: To investigate the presence and distribution of severe acute respiratory syndrome (SARS)-associated coronavirus (SARS-CoV) in autopsy tissues obtained from patients died of SARS.

Methods: Immunohistochemical technique was applied in 4 fatal SARS cases to examine the autopsy tissues including the lungs, spleen, lymph nodes, brain, pituitary, heart, liver, kidney, pancreas, trachea, esophagus, gastrointestinal tract, adrenal glands, parathyroids, skin and bone marrow.

Results: Immunohistochemistry identified positive monoclonal antibody against SARS-CoV nuceeocapsid (N) protein in the alveolar epithelium and the infiltrating monocytes or macrophages in the lung, spleen and lymph nodes; the presence of the antibody was also detected in the serous gland epithelium of the trachea/bronchus, squamous epithelium of the esophagus, the gastric parietal cells, the epithelium of the intestinal tract, acidophilic cells in the parathyroids and pituitary, acinus cells in the pancreas, adrenal cortical cells, sweat gland cells, small vessel endothelium, bone marrow promyelocytes, epithelial cells of the distal convoluted tubule of the kidney, brain neurons, and the hepatocytes near the central vein.

The clinical pathology of severe acute respiratory syndrome (SARS): a report from China.

In order to investigate the clinical pathology of severe acute respiratory syndrome (SARS), the autopsies of three patients who died from SARS in Nan Fang Hospital Guangdong, China were studied retrospectively. Routine haematoxylin and eosin (H&E) staining was used to study all of the tissues from the three cases. The lung tissue specimens were studied further with Macchiavello staining, viral inclusion body staining, reticulin staining, PAS staining, immunohistochemistry, ultrathin sectioning and staining, light microscopy, and transmission electron microscopy.