Influences of preparation techniques on glass-forming ability of Fe-P-B-Si-C amorphous alloys

It has been widely accepted that the ultrafast cooling rate is required for the glass formation of amorphous alloys. Here, the larger glass-forming ability （GFA） of Fe76P5（B0.5Si0.3C0.2）19 amorphous alloy was achieved by water quenching at lower cooling rate under argon atmosphere. Cylindrical rods with diameters of 1-2 mm were prepared by water quenching without flux treatment, Cu-mold injection casting, and Cu-mold suction casting, respectively. The influences of the preparation techniques with different cooling rates on GFA, thermal property, and nucleation/growth behavior were examined. The critical diameter of the Fe76P5（B0.5Si0.3C0.2）19 amorphous alloys is 1.7 mm for water quenching while smaller than 1.0 mm for injection casting. Microstructure analysis indicates that the crystallization and solidification processes are quite different between the water-quenched and the injection-cast rods. These findings could deepen fun-damental understanding on the relationship between the cooling rate, techniques, and GFA of Fe-based amorphous alloys.

A supercritical CO_2 fluid technique for the preparation and evaluation of rhBMP-2-loaded PLLA microspheres

Introduction The use of supercritical fluids such as supercritical CO2（scCO2） has provided a ’clean’ and effective alternative to traditional methods of protein delivery systems.Here。

High Thermoelectric Figure of Merit of Ag8SnS6 Component Prepared by Electrodeposition Technique

A new thermoelectric material Ag8SnS6, with ultra-low thermal conductivity in thin film shape, is prepared on indium tin oxide coated g/ass （ITO） substrates using a chemical process via the electrodeposition technique. The structural, thermal and electrical properties are studied and presented in detail, which demonstrate that the material is of semiconductor type, orthorhombic structure, with a band gap in the order of 1.56eV and a free carrier concentration of 1.46 × 10^17 cm-3. The thermal conductivity, thermal diffusivity, thermal conduction mode, Seebeck coefficient and electrical conductivity are determined using the photo-thermal deflection technique combined with the Boltzmann transport theory and Cahill＇s model, showing that the AgsSnS6 material has a low thermal conductivity of 3.8 Wm - 1K- 1, high electrical conductivity of 2.4 × 10^5 Sm- 1, Seebeck coefficient of -180μVK-1 and a power factor of 6.9mWK-2m-1, implying that it is more efficient than those obtained in recently experimental investigations for thermoelectric devices.

A Comparison of Techniques for Preparing Somatic Chromosomes in Ribes Species

Ribes plants,like most of other fruit trees,are characterized by their large number but small size of somatic chromosomes.In the light of these special characteristics,we have examined several factorial combinations of material, pretreatment,slide preparing method and stain to identify the most promising techique for studying the chromosomes and further analyzing the karyotypes and chromosome banding of Ribes plants. The resuts indicated that the combination of root tip with pretreatment of 2 m molL-1 8-hydroxyquinoline plus 0.05% colchicine or 0.3% balm for 3～5 hours at 14℃,pre-hypotonic trcarment of 0.07mol L-1 KCl for 30 min, fixation in Carnoy's fluid,hydrolysis in 5% cellulase and 5% pectinase mixture for 4～5 hours at 25℃, post-hypotonic treatment in distilled water for half an hour and staining in Giemsa could make the chromosome prepa ration superior to other treatment combinations.

Sprayed separation membranes: A systematic review and prospective opportunities

Membrane separation technology has been taken up for use in diverse applications such as water treatment,pharmaceutical,petroleum,and energy-related industries.Compared with the design of membrane materials,the innovation of membrane preparation technique is more urgent for the development of membrane separation technology,because it not only affects physicochemical properties and separation performance of the fabricated membranes,but also determines their potential in industrialized application.Among the various membrane preparation methods,spray technique has recently gained increasing attention because of its low cost,rapidity,scalability,minimum of environmental burden,and viability for nearly unlimited range of materials.In this Review article,we summarized and discussed the recent developments in separation membranes using the spray technique,including the fundamentals,important features and applications.The present challenges and future considerations have been touched to provide inspired insights for developing the sprayed separation membranes.

Fabrication of 2×2 Thermo-Optic Switches with Organic-Inorganic Hybrid Materials Prepared by Sol-Gel Technique

2×2 Mach-Zehnder interferometric thermo-optic switch was fabricated with organic/inorganic hybrid materials by sol-gel technique and direct UV patterning. The switching time of device was measured to be 4.2 ms and switching power 9.3 mW.

Improvement of thickness uniformity and elements distribution homogeneity for multicomponent films prepared by coaxial scanning pulsed laser deposition technique

In conventional pulsed laser deposition （PLD） technique, plume deflection and composition distribution change with the laser incident direction and pulse energy, then causing uneven film thickness and composition distribution for a multicomponent film and eventually leading to low device quality and low rate of final products. We present a novel method based on PLD for depositing large CIGS films with uni- form thickness and stoichiometry. By oscillating a mirror placed coaxially with the incident laser beam, the laser＇s focus is scanned across the rotating target surface. This arrangement maintains a constant re- flectance and optical distance, ensuring that a consistent energy density is delivered to the target surface by each laser pulse. Scanning the laser spot across the target suppresses the formation of micro-columns, and thus the plume deflection effect that reduces film uniformity in conventional PLD technique is eliminated. This coaxial scanning PLD method is used to deposit a CIGS film, 500 nm thick, with thickness uniformity exceeding ±3% within a 5 cm diameter, and exhibiting a highly homogeneous elemental distribution.

Research progress in Mg-based hydrogen storage alloys

Magnesium and magnesium-based alloy hydrides remain attractive hydrogen storage materials owing to high hydrogen capacity and rich reserves in the earth＇s crust. A high stability of hydride and sluggish hydriding/dehydriding kinetics at practical temperatures for the materials drove researchers into alloying with other elements, using different preparation techniques, using catalyst and thin film hydride to improve the hydrogen absorption/desorption properties. In this review, the development of these approaches and their effects on the thermodynamic and kinetics properties of magnesium and magnesium-based alloy hydrides were descript in details.

Promising high-thermal-conductivity substrate material for high-power electronic device:silicon nitride ceramics

High-thermal-conductivity silicon nitride ceramic substrates are indispensable components for nextgeneration high-power electronic devices because of their excellent mechanical properties and high thermal conductivities, which make them suitable for applications in complex and extreme environments. Here, we present an overview of the recent developments in the preparation of high-thermal-conductivity silicon nitride ceramics. First,the factors affecting the thermal conductivity of silicon nitride ceramics are described. These include lattice oxygen and grain boundary phases, as well the oxygen content of the crystal lattice, which is the main influencing factor.Then, the methods to prepare high-thermal-conductivity silicon nitride ceramics are presented. Recent work on the preparation of high-thermal-conductivity silicon nitride is described in detail, including the raw materials used and the forming and sintering processes. Although great progress has been made, the development of a high-quality,low-cost fabrication process remains a challenge. Nevertheless, we believe that high-thermal-conductivity silicon nitride substrates are promising for massive practical applications in the next generation of high-power electronic devices.

Monodispersed Co@C nanoparticles anchored on reclaimed carbon black toward high-performance electromagnetic wave absorption

Recently,developing carbon-based hybrid materials loaded with magnetic components has been generally regarded as a promising and practically feasible strategy when it comes to constructing lightweight electromagnetic wave absorbers.In the current work,reclaimed carbon black(CB)nanopowder was firstly produced by simple burning of wheat straw,which was then employed as sustainable carbon-based host materials(carrier)and successfully decorated Co@C nanoparticles via a simple thermal reduction process.Remarkably,both the as-fabricated nanocomposites and corresponding electromagnetic wave absorption performances could be effectively tuned by tailoring the dosage of the Co@C nanoparticles.The minimum reflection loss(RLmin)of–53.989 d B was achieved for CB/Co@C-2#at 2.28 mm thickness,meanwhile,CB/Co@C-3#was featured by a wide effective absorption band(EAB)of 6 GHz(6.72–12.72 GHz)at a 2.73 mm matching thickness,which covered the entire X band,suggesting that the CB/Co@C nanocomposites were an attractive candidate for electromagnetic wave absorber.According to the synergistic influence of dielectric loss and magnetic loss from CB and Co@C,respectively,as well as the properly matched impedance,a reasonable electromagnetic wave attenuation mechanism was illustrated.It is noteworthy that the preparation process of CB is a facile,recycled,and low-cost strategy for achieving nanoscale carbon-based absorbing materials,moreover,the CB/Co@C nanocomposites provide a reference for constructing lightweight dielectric-magnetic products with superb electromagnetic wave absorption performances.

Two-dimensional molecular crystalline semiconductors towards advanced organic optoelectronics

The compelling demand for higher performance and lower cost in the optoelectronics industry has driven the development of organic semiconductors.Molecular crystalline semiconductors(MCSs),especially two-dimensional MCSs(2D-MCSs),possess intrinsic ordered structure,quantum confinement effect,high mobility,unique optical and electrical properties,and more ecological and cheaper production,which make great promises in high-performance optoelectronic applications.Here we provide a review of design principles and synthetic strategies for 2D-MCS materials,exploiting their potential as a revolution option in associated optoelectronic devices.The merits and limitations of each strategy are presented,and these molecular crystals are considered as a competitive choice for emerging semiconducting materials in information science.Finally,the current challenges and future perspectives in this field are also elaborated.

Magnetostrictive alloys:Promising materials for biomedical applications

Magnetostrictive alloys have attracted increasing attention in biomedical applications because of the ability to generate reversible deformation in the presence of external magnetic fields.This review focuses on the advances in magnetostrictive alloys and their biomedical applications.The theories of magnetostriction are systematically summarized.The different types of magnetostrictive alloys and their preparation methods are also reviewed in detail.The magnetostrictive strains and phase compositions of typical magnetostrictive alloys,including iron based,rare-earth based and ferrite materials,are presented.Besides,a variety of approaches to preparing rods,blocks and films of magnetostriction materials,as well as the corresponding methods and setups for magnetostriction measurement,are summarized and discussed.Moreover,the interactions between magnetostrictive alloys and cells are analyzed and emphasis is placed on the transduction and transformation process of mechanochemical signals induced by magnetostriction.The latest applications of magnetostrictive alloys in remote microactuators,magnetic field sensors,wireless implantable devices and biodegradable implants are also reviewed.Furthermore,future research directions of magnetostrictive alloys are prospected with focus on their potential applications in remote cell actuation and bone repair.