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Recycled concrete powder (RCP) recycling can reduce the consumption of natural resources, which has been highlighted as an ecofriendly and sustainable approach. The alkali-activated slag (AAS) offers notable prospects for replacing conventional Portland cement binders. In this study, we partially replaced granulated blast furnace slag (GBFS) with RCP to prepare the AAS mortars. We evaluated the effect of RCP replacement levels and fineness levels on compressive strength, early hydration process, and pore structure pertaining to AAS mortars with RCP (RCP-AAS mortars). According to the experimental results, using 10–30% RCP inside AAS mortars enhanced the compressive strength at 1 day, and the improvement was obvious with increasing RCP fineness. The RCP delayed the early-age hydration of the GBFS, decreased the content of hydration products and increased the total porosity. Therefore, it exhibited a negative effect on 28-day compressive strength. These drawbacks of RCP however, could be modified by increasing its fineness.

Non-noble metal electrocatalysts have attracted great attention on account of low cost, good stability, and excellent hydrogen evolution performance. One of the most efficient approaches to increas...

Field-programmable photonic array-based chips will be key components in realizing high-performance THz communication in the future. However, the optical diffraction limit prohibits their integration in chip-level sizes. Although plasmonic waveguides combined with graphene are able to possess mode transmission at THz wavelengths, their operational problems such as complex device structures or high transmission losses still cannot be addressed effectively. In this paper, by relying on a mechanism of THz surface plasmon mode of graphene and an energy distribution mechanism of the refractive index difference region, a novel hybrid graphene plasmonic waveguide is proposed, whose core design part is a simple gap-slot region. This waveguide's transmission distance is one order of magnitude longer than that of the conventional waveguide while retaining the benefit high energy confinement, under appropriate parameters. Hence the proposed waveguide can be an efficient candidate component of field-programmable photonic arrays for THz communication.

Polypropylene fibre (PPF) is a kind of polymer material with light weight, high strength, and corrosion resistance. The crack resistance of concrete can be improved by adding PPFs. PPF can optimize the pore size distribution of concrete. As a result, the durability of concrete is significantly enhanced since PPF can block the penetration of water or harmful ions in concrete. This paper summarizes the influence of polypropylene fibre on the durability of concrete, including drying shrinkage, creep, water absorption, permeability resistance, chloride ion penetration resistance, sulfate corrosion resistance, freeze-thaw cycle resistance, carbonation resistance, and fire resistance. The authors analysed the effects of fibre content, fibre diameter, and fibre hybrid ratio on these durability indexes. The durability property of concrete can be further improved by combining PPFs and steel fibres. The drawbacks of PPF in application in concrete are the imperfect dispersion in concrete and weak bonding with cement matrix. The methods to overcome these drawbacks are to use fibre modified with nanoactive powder or chemical treatment. At last, the authors give the future research prospects of concrete made with PPFs.

Surface texturing is an effective approach to improve the tribological properties of mechanical components. An indentation method is presented to fabricate dimple textures on bronze specimen surfaces. Graphite was selected as the mating balls in ball-on-disc wear tests. The worn surfaces and the indented dimples heaped with the thin ribbon debris were observed by microscope. The morphology and evolution of wear debris were employed to explain the influence of indented dimple textures. The experimental results indicate that the generation of thin ribbon debris is due to the edge hardening of indented dimple. The thin ribbon debris and the indented conical dimple are conducive to the debris heaping on slopes of dimples, which can facilitate the formation of the graphite-rich transfer layers on indented dimple surface. Compared with nontextured surface, indented dimple surface has lower coefficients of friction and slighter wear. The tribological properties of indented dimple surface are improved because of the edge hardening, the debris heaping and the formation of transfer layers.

The synthesis of highly active, stable and cost-effective electrocatalysts for overall water splitting is critical but challenging. Herein, we synthesized nickel-doped pyrrhotite iron sulfide (Fe0.95−xNixS1.05) nanosheets via a one-pot synthetic route. When tested for oxygen evolution reaction (OER) performance in alkaline solutions, the as-prepared Fe0.8Ni0.15S1.05 catalyst exhibited superior electrocatalytic performance to commercial IrO2 with a current density of 10 mA cm−2 at an overpotential of 228 mV, and a Tafel slope of 53 mV dec−1. The hydrogen evolution reaction (HER) activity was achieved on Fe0.8Ni0.15S1.05 with a Tafel slope of 103 mV per decade, and a current density of 10 mA cm−2 at an overpotential of 263 mV. With nickel doping, the as-prepared pyrrhotite iron sulfide nanosheets can expose more active sites, and hence act as a highly efficient catalyst for overall water splitting.

Fe3O4-intercalated reduced graphene oxide (Fe3O4-rGO) nanocomposites were synthesized by an in situ reduction process. The results of XRD and XPS analyses suggested the successful formation of a Fe3O4 crystal phase within the rGO sheets. The SEM and TEM images demonstrated that Fe3O4 was flaky and was inserted stably within the rGO layers to form a typical sandwich-like structure. The hysteresis loops revealed the superparamagnetic behavior of the Fe3O4-rGO nanocomposites at room temperature. The electromagnetic parameters revealed that Fe3O4-rGO nanocomposites exhibited multiple dielectric relaxation and magnetic resonance. The reflection loss revealed that the maximum loss was −49.53 dB at 6.32 GHz for a thickness of 3.4 mm while the highest effective absorption bandwidth was 2.96 GHz.

High-strength concrete (HSC) is widely used in practice, which is due to its potential benefits, such as good workability, long durability, low permeability. However, higher autogenous shrinkage occurs owing to the low water-to-cement (w/c) ratio of HSC, which would reduce the cracking resistance. Therefore, Dramix 3D steel fibers are applied to strengthen the early-age properties of HSC to increase the cracking resistance. Although investigations on the effect of steel fiber on the properties of HSC have been conducted, investigations on the effect of Dramix 3D steel fiber on the autogenous shrinkage, temperature history, restrained stress, mechanical properties, and cracking resistance of HSC remain lacking. In present study, Temperature Stress Test Machine (TSTM) was utilized to investigate the properties of HSC reinforced with Dramix 3D steel fiber at early age. The test results and corresponding analysis indicated that: (1) the absolute value of autogenous shrinkage of HSC decreased with the increase of the amount of Dramix 3D steel fiber, and a model for autogenous shrinkage was proposed; (2) the temperature or temperature drop at cracking time of HSC decreased or increased with the increase of the amount of Dramix 3D steel fiber; (3) the stress at room temperature, cracking stress, ratio of cracking stress to tensile strength, and stress reserve of HSC increased with the increase of the amount of Dramix 3D steel fiber; (4) the addition of Dramix 3D steel fiber improved the cracking resistance of HSC.

A batteryless DC-DC boost converter with low startup voltage for thermoelectric energy harvesting applications is implemented in a TSMC 0.18µm CMOS process. A LC oscillator enables the converter to operate from a 200-m V input voltage. A high duty cycle controls the switching frequency of the pulse frequency modulation (PFM) boost converter to lower its switching loss, with output voltage regulated at 1.1V and peak efficiency of 63%.

Millions of tons of hazardous iron oxide residues are produced during the iron purification process of sulphate leaching solutions in nonferrous metals hydrometallurgy industry per year. The generated iron oxide residues, which mainly contain goethite and gypsum precipitates adsorbing the hazardous elements of arsenic, sulfur, zinc, and germanium, pose a great threat to the local ecological environment and human health. A novel method for the treatment and recovery of goethite and gypsum by synthetic magnetic nanoparticles (MNPs) such as α-Fe3O4 and γ-Fe2O3 are proposed to treat the residues efficiently and cost-effectively. MNPs serve as the magnetic crystal nuclei of the goethite precipitates during the iron purification process, and the goethite and gypsum precipitates formed under this condition can be separated in magnetic field. Subsequently, the magnetic crystal nuclei were treated using a rod milling and magnetic collecting to obtain goethite precipitates in order to minimize costs. Both precipitates can be digested as raw materials of iron making and building materials, respectively. Additionally, we found that the separation efficiency of the goethite and gypsum precipitates was much higher when γ-Fe2O3 was used as the crystal nuclei, indicating that the surface of γ-Fe2O3 was more favorable for the formation of goethite particles than α-Fe3O4.

An integrated technological route for comprehensive utilization of red mud through the extraction of valuable components and reuse of the magnetic residue is proposed. In this study, inductively coupled plasma atomic emission spectroscopy, X-ray fluorescence, X-ray powder diffraction, and vibrating sample magnetometer were used to characterize the process. The process includes sintering, alkaline leaching to recover Na and Al, and removal of lead ions from wastewater by magnetic residue containing magnesium ferrite. The effects of various parameters were systematically investigated, and the optimal conditions were determined as: sintering temperature of 1150 °C and duration of 60 min, the mole ratio of CaO/SiO2 of 3, Na2O/Al2O3 of 1.2, and MgO/Fe2O3 of 1 in the raw material. Under the conditions, the results showed that approximately 74% Al and 95% Na were recovered from red mud by this route. The leach residue exhibits magnetic and adsorption properties, its adsorption capacity reaching about 70 mg/g at the initial Pb2+ concentration of 80 mg/L. Therefore, it may be a promising candidate in wastewater treatment and other fields.

In recent years, great attention has been devoted to transition metal-based dichalcogenides (TMDs), in particular to the 1 T-phase enriched TMDs, which possess much higher hydrogen evolution reaction (HER) activity than the 2H-phase. Currently, how to prepare the stable metallic phase TMDs nanomaterials to achieve an endurable HER is one of the main challenges for practical applications. In this study, we present a reliable and tunable 1 T-phase TMDs-based synthetic strategy to atomically engineer non-metal doping sites onto metallic 1 T-WS2. Benefiting from engineering phosphorus atoms, the optimized electrocatalyst shows great enhancement in the HER. We reveal that P doped WS2 will produce 1 T-phase enriched WS2|P catalyst, which is beneficial to expose more active sites and improve the conductivity of the material. More interestingly, the HER activities of 1 T-WS2|P-5 electrocatalyst outperforms 2H-WS2, demonstrating a low overpotential (ηHER = 125 mV @ 10 mA cm−2), a small Tafel slope (HER = 73.73 mV dec−1), and significant durability under acidic conditions. Simultaneously, the 1 T-WS2|P-5 catalyst also presents an overpotential of 190 mV at 10 mA cm−2 and a low Tafel slope of 92.11 mV dec−1 under alkaline conditions. Moreover, the catalyst has excellent catalytic stability under acidic and alkaline conditions. We introduce the first example of 1 T phase enrichment P doped WS2 as a HER electrochemical catalyst, and this work is expected to open a new door for the discovery of other 1 T-phase TMDs as effective catalysts for renewable energy.

Metal-organic frameworks (MOFs), as 3D porous precursors, have demonstrated great potential as electrode materials for lithium storage on account of high specific area and tunable structure. To enhance the intrinsic performance and endow MOFs with versatility, constructing distinctive morphology of MOFs while maintaining their porous structure to satisfy various application is highly desirable. Herein, we successfully developed a facile strategy for rationally designing and synthesizing the morphology of MOFs from circular plate shape to truncated octahedron gem shape via regulating the ratio of Pluronic F127 to terephthalic acid. In addition, the as-prepared Pluronic F127-regulated Ti-based MOFs (F-MIL-125-Ti) sacrifice as precursor to derive 3D mesoporous titanium dioxide (TiO2) and as template for in situ growth of molybdenum disulfide (MoS2) nanosheets to prepare a truncated octahedron TiO2@C@MoS2 hierarchical composite. As expected, the distinctive 3D hierarchical TiO2@C@MoS2 electrode exhibits superb rate capability (775 mAh g−1 at 5 C) and outstanding cycling stability (822 mAh g−1 after 1000 cycles at 1 C), which is benefiting from the 3D mesoporous TiO2 and synergies between TiO2 and MoS2 nanosheets. This work develops new insight to design novel and controllable morphology MOFs-derived materials for application of energy storage devices.

To obtain a low-density material that is capable of absorbing electromagnetic waves over a wide bandwidth, an activated carbon fiber/Fe3O4 composite material (ACF/Fe3O4) was prepared using an in situ reduction method. Scanning electron microscopy images show that Fe3O4 nanoparticles, approximately 10–40 nm in size, were spread uniformly over the surface of the ACF. The resulting composite exhibited superparamagnetic behavior at room temperature. The ability of the ACF and ACF/Fe3O4 composite to absorb electromagnetic waves over a frequency range of 8.2–18 GHz was measured using the arch method. The results showed that the maximum reflectivity of an ACF felt was −12.9 dB at 18 GHz, and the effective microwave-absorbing bandwidth (R < −10 dB) was 1.9 GHz (16.10–18 GHz). The absorption performance of the ACF was greatly enhanced by being loaded with Fe3O4 nanoparticles; the maximum reflectivity of the 2 mm layer of the ACF/Fe3O4 composite was −30.07 dB at 16.45 GHz, and the effective bandwidth (R < −10 dB) increased to 8.62 GHz (9.38–18 GHz). Coating with nano-Fe3O4 magnetic particles can effectively improve the absorption of electromagnetic waves by the ACF, and this technique therefore has great potential for application to the field of electromagnetic shielding.

To analysis the electrostatic risk in the mixing process of typical propellants, the distribution of the electrostatic field inside the cylinders was investigated. The maximum charge quantity (−1.895 μC kg−1) and relative dielectric constant (1.88) of 11/7 propellant were obtained through experiments. Based on Ansoft Maxwell electrostatic field numerical analysis, the electrostatic field intensity and potential distribution inside the cylinder were obtained. The maximum electrostatic field intensity and potential of 11/7 propellant increased with the propellant height. When the propellant height increased to 290 mm with a diameter of 300 mm, the maximum field intensity at the bottom was 15.1 MV/m.

Fabrication of miniaturized titanium thin-walled products directly using sheet metals is proven to be a promising approach with high productivity. In this process, however, there are many unknowns in terms of size effect and its affected fracture behavior. This study is thus aimed at investigating the effect of grain size on the fracture behavior of commercially pure titanium (CP–Ti) sheets with a thickness of 0.1 mm. Tensile tests combined with a digital image correlation (DIC) measurement system were conducted to determine the critical fracture stress of the specimens with different grain sizes. The fracture morphologies of the stretched specimens were further characterized by a scanning electron microscope (SEM). According to the experimental observation, an evident transition from ductile to brittle fracture as the grain size increases from 33.1 to 107.7 μm is revealed. Macroscopically, the elongation and critical fracture stress decrease with the increase of grain size. While according to the microscopic observations, the number of dimples decreases with the increase of grain size. Meanwhile the cleavage planes and river patterns gradually appear in the coarse grain fracture surface. To explore the fracture mechanism, transmission electron microscope (TEM) observations were made utilizing the specimens with fine and coarse grains. Significant dislocation emission from crack-tips was revealed at different grain sizes. Moreover, evident dislocation pile-up at grain boundaries was observed in the specimen with a grain size of 33.1 μm. Those intense dislocations reduce the effective stress at the crack tip resulting in higher crack propagation resistance. Nevertheless, the dislocation density at crack-tip decreases strongly with the increase of grain size leading to high crack-tip effective stress and less crack plasticity. Thus cleavage fracture was dominated in coarse grain CP-Ti sheets. A dislocation shielding model was developed to capture the dislocation observation in various grain sizes. The critical stress onset of CP-Ti sheets fracture during the tensile test was also predicted for validation.

Fe-based electrocatalysts have attracted significant attention on account of the possibility for the realization of low-cost, high efficiency, and stable oxygen evolution reaction (OER) in alkaline solution. In this study, we present a new type of Fe(SexS1−x)2 nanorod bundles, which were successfully synthesized via a simple one-step hydrothermal method. We further demonstrate the applicability of these structures as electrocatalysts for OER application. We reveal that the incorporation of S into FeSe2 cause lattice strain and lattice defect, which is beneficial to expose more active sites and optimize the electronic structure, and hence the Fe(SexS1−x)2 composites display favorable catalytic for OER. More interestingly, the as-prepared Fe(Se0.5S0.5)2 catalyst exhibits the best OER performance with an overpotential at 10 mA·cm−2 of 247 mV, a low tafel slope of 54 mV/dec, and excellent catalytic stability. This work is expected to open a new door to discover other Fe-based materials as efficient catalysts for renewable energy.

Expensive diamond grains remaining within waste diamond grinding wheels and wheel substrate need to be recycled. Electroplated diamond grinding wheel was taken as an example. An idea of “substrate structure-induced cracks (SSIC)” was proposed to solve the disassembly problem of waste electroplated diamond wheels. An assembled substrate for electroplated diamond grinding wheel was designed. Fabrication and disassembly experiments of electroplated diamond wheel with assembled substrate were carried out. Also, finite element analysis was used to investigate the mechanism of disassembly processes. Recycling experiments of electroplated diamond wheels were carried out in three ways, namely acid corrosion method, electrolysis method and SSIC method. The experimental results show that cracks generate in the diamond abrasive layer of the assembled wheel. The simulated maximum principal stress occurs on diamond abrasive layer near the mating surface between cylindrical pins and substrate, which is consistent with the location where the crack is created. The abrasive layer can be easily peeled off from substrate after the cracks occur on abrasive layer. Compared with electrolysis and acid corrosion methods, the SSIC method has the shortest disassembly time and the lowest disassembly costs. The assembled substrate provides possibility to exert cracking forces from substrate to diamond abrasive layer. With assembled substrate, the nondestructive disassembly of electroplated diamond wheel can be fulfilled. Assembled substrate can meet the need of DFD for electroplated diamond grinding wheel.

In this paper, a research work on the influence of metal particles on lightning impulse discharge characteristics of transformer insulating oil is carried out. The main research contents are as follows: The lightning impulse discharge test platform for insulating oil was established. The influence of the development characteristics and breakdown characteristics of the streamer in the insulating oil with different metal particle concentration under pre-breakdown voltage was studied. The discharge characteristics of pure insulating oil and particle-containing granular insulating oil were compared and analyzed. The breakdown characteristics of insulating oil with different metal particle concentration under different oil gaps were measured, and the influence of metal particles on the lightning breakdown characteristics of insulating oil was obtained. The results show that the metal particles promote the initiation and development of the streamer in the oil. The stop length and development speed of the streamer are positively correlated with the particle concentration, while the initial voltage of the insulating oil is negatively correlated with the breakdown voltage and the particle concentration.

Experiments were performed to examine the friction and wear of laser dimple textured surfaces of medium carbon steel under three conditions: normal, degaussing, and an additional magnetic field. The coefficients of friction and wear volume of the laser dimple textured surfaces were measured, and the hardness of the dimple edge were measured. The worn surfaces of the specimens were examined, and the elemental contents of the wear debris were analysed. The wear debris within the laser dimples was examined at regular intervals to analyse the trapping processes. The experimental results indicated that the coefficients of friction and wear volume mass were reduced by the laser dimple textured surface. Compared with the normal condition, the abrasive wear of the laser dimple textured surface was reduced under both the degaussing and additional magnetic conditions, and the coefficients of friction and wear were reduced. Under the additional magnetic condition, uniform debris attachment to the inner walls of the laser dimples occurred. The distributions of the magnetic domains within the specimens affected the trapping process of wear debris during the wear experiments, and the wear-debris trapping capacity of the laser dimples was improved under the additional magnetic condition. The following phenomena occurred under the additional magnetic condition: hardness improvement of the dimple edge, oxidation of the wear debris, and coverage of the worn surfaces by wear debris. The results indicate that the tribological performance of the laser dimple textured surface of medium carbon steel can be improved under degaussing and additional magnetic conditions.

Anand constitutive model of SnAgCuFe solder joints was studied, and 9 parameters were determined based on tensile testing. And the model was incorporated in finite element code for analyzing the stress-strain response of SnAgCuFe solder joints in WLCSP30 device. The results indicate that the maximum stress concentrates on the top surface of corner solder joints, and the stress-strain of SnAgCuFe solder joints is lower than that of SnAgCu solder joints. Based on the fatigue life model, the addition of Fe can enhance the fatigue life of SnAgCu solder joints. Therefore, the SnAgCuFe solders can replace the traditional SnPb to be used in electronic packaging

This paper reports the Raman spectra and electrical analysis of Se-deficient Cu(In,Ga)Se2 (CIGS) films with various Cu contents. These films were deposited by low-cost two-step process consisting of sputtering of metallic precursor and subsequent selenization. Raman spectra exhibit the formation of chalcopyrite phase while signs of secondary phases like CuxSe and ordered vacancy compound are also observed. Electrical measurements show the change of main carrier source as well as the transformation of conduction type with varying Cu content. Comprehensive analysis of Raman spectra and electrical measurements qualitatively explains the relationship between electrical properties and Cu contents. Based on this relationship, the optimal range of Cu/(Ga + In) for Se-deficient CIGS solar cells is identified as 0.875–0.925, which is smaller than that for Se-sufficient CIGS solar cells due to the presence of Se vacancies. The efficiency data of CIGS solar cells fabricated with same absorber deposition process are in good agreement with this optimal range. The results of this paper could be used to estimate device performance at early process stages.

Fe3O4-intercalated reduced graphene oxide (Fe3O4-rGO) nanocomposites were prepared by an in-situ reduction method. We studied the effect of preparation conditions, including GO:Fe3+ molar ratio and reduction temperature, on the structure and electromagnetic wave absorption properties of the nanocomposites. The Fe3O4-rGO nanocomposites have a typical sandwich structure at a 1:1 M ratio. Increasing the reduction temperature above 500 °C yielded a relatively pure Fe3O4 crystalline phase. Furthermore, changes in the microstructure effectively influence the matching performance of the material. A reasonable molar ratio and reduction temperature yields a composite with improved impedance matching and thickness matching characteristics. At a ratio of 1:1 and reduction temperature of 600 °C, the actual matching thickness of the material conforms to the quarter-wavelength theory, and the input impedance of the material matches the air impedance. As a result, electromagnetic waves enter the interior of the composite unhindered, where they can be effectively attenuated, thereby further improving the wave absorption properties of the material. When the thickness is 3 mm, the maximum reflectance at 8.6 GHz reaches −49.6 dB with an effective bandwidth of 2.72 GHz.

To obtain better chip breaking effect for most cutting parameters, a chip breaker which position on rake face of tool can be adjusted is designed and analyzed. According to the structure and installation features of the PCD insert, structure of adjustable chip breaker is designed. Through finite element simulation and cutting experiments, the influences of chip breaker parameters on the radius of chip curl curvature were analyzed to determine the parameters of chip breaker. Forces on chips and the chip breaking processes of PCD tool with chip breaker were analyzed. The geometric relationships between chip breaker and chip were established. According to the geometric relationship and the chip breaking criterion, the formulas of three chip breaker parameters were deduced. A design method for chip breaker parameters of PCD tool was proposed. The research results show that the radius of chip curl curvature decreases as the inclination angle increases and decreases as the position parameter decreases. There is a threshold for both inclination angle and the position parameter of the chip breaker, and if the threshold is exceeded, severe noise and chip build-up will occur. If the contact point between the chip and the chip breaker is located in the selected segment of chip, the extrusion force between the chip and the chip breaker will increase as the chip grows, which can cause the chip to crack and break easily. The influence mechanisms of inclination angle and the position parameter of chip breaker on chip curling are obtained. A simple set of equations are derived for designing chip breaker parameters, including inclination angle, position parameter and height. A design method for chip breaker parameters of PCD tool is presented. The application of the chip breaker can expand the chip breaking range of cutting parameters for PCD tools.

The gantry CNC machine tool has unique structure and characteristic. It does not always form a symmetrical structure and symmetrical force during the machining process. The inconsistency will cause a non-synchronised error in the biaxial synchronous system. The no-synchronised error will affect the machining accuracy, cause the beam to be pulled and the gantry frame or drive element to be damaged. Therefore, the biaxial synchronisation error of the CNC machine tool is one of its most important specifications, and it should be solved firstly when compensating. This paper presents a new method called single laser synchronisation method, and puts forward the measurement method and compensation method of positioning error. This new method includes a special optical path layout, a characteristic way of measurement and compensation. This method has some advantages such as high precision, low-cost, efficiency, etc.

Pb&ndash, BHA complexes have been shown to be selective for the separation of tungsten and cassiterite minerals from calcium minerals. These minerals could be enriched synchronously to some extent using Pb&ndash, BHA complexes flotation. However, it is difficult to further improve the quality and recovery of the scheelite, wolframite, and cassiterite concentrate due to their different behavior in flotation, such as flotation rate and sensitivities to depressants. Moreover, the super fine particles create some challenges for the cleaning flotation process. In this study, advanced gravity separators for super fine particles were introduced for the cleaning process based on the slight difference in the specific gravity of scheelite, wolframite, and cassiterite. The new process featured pre-enrichment using Pb&ndash, BHA flotation, and upgrading using gravity separation, taking into account both the similarities and differences in floatability and density of the different minerals. The grades of WO3 and Sn in the concentrate of the new process reached to 61% and 2.89%, respectively, and the recovery of Sn was significantly improved. In addition, gravity separation is highly efficient, cost effective, and chemical-free, which is environmentally friendly. This study has proven that physical separation can be used for the purification of flotation products and provide some solutions for separation problems of complex refractory ores, which has, up until now, been rarely reported in the literature and/or applied in mineral processing.

Non-Newtonian fluid is a kind of fluid that its shear stress is not always keeps a linear relationship with the shear strain rate. An overview of its applications was made here. Based on the special rheological properties, non-Newtonian fluids are divided into different types and used as additives, mediums and protective materials in many fields. The paper focuses on its applications in fluid rheological properties improving, damping devices, individual protection equipments and mechanical processing. The main achievements in application of the non-Newtonian fluid were introduced and a further prospect was also summarized.

Water-soluble surface modified silver nanoparticles were synthesized by liquid phase reduction with tannic acid as the reductant and polyvinyl pyrrolidone (PVP) as the surface modification agent.The structure and morphology of the as-synthesized powders were investigated by X-ray powder diffraction (XRD),transmission electron microscopy (TEM),ultraviolet-visible (UV-Vis) absorption spectroscopy,and Fourier-transform infrared (FTIR) spectrometry.The antibacterial activity of the water-soluble Ag nanoparticles against Escherichia coli (E.coli) and Staphylococcus aureus (S.aureus) was investigated by broth dilution.The stable dispersion duration of the as-synthesized Ag nanoparticles in water was also determined.A mechanism for PVP modified Ag nanoparticle formation is proposed.The results show that the as-synthesized PVP modified Ag nanoparticles have a face-centered cubic crystalline structure.The average diameter of the Ag nanoparticles ranges from 15 to 17 nm.The assynthesized powders have good solubility in water over a long period of time.PVP modified Ag nanoparticles exhibit good antibacterial properties against E.coli and S.aureus.This simple and mild preparation method can be easily increased to an industrial scale process and,therefore,PVP modified Ag nanoparticles are potentially a new type of antibacterial.

To examine the biodegradability and bone healing effect of a novel biodegradable coralline hydroxyapatite after implanting into the proximal tibia of rabbit. Seventy New Zealand white rabbits were enrolled, bone defects about 10 × 5 × 3 mm3 of bilateral proximal tibias were prepared by drilling, then coralline hydroxyapatite and iliac crest bone were grafted into bilateral bone defects, respectively. Each time five rabbits were sacrificed at 1, 2, 3, 4, 6, 8, 10, 12, 20, 24, 32, 36, 40, and 60 weeks after surgery. Then a series of examination were carried out, including eye view, roentgenographically, and nondecalcification histological examination. Eye view and roentgenographical examination indicate that all the defects grafted with coralline hydroxyapatite exhibited bone fusion, similar to the iliac crest autograft. The bone density of the graft site decreases with time on the X-ray film. Nondecalcification histological examination results are as followed: In the early time on the sections, the coralline hydroxyapatite looks like interlinked trabecula. Few lymphocytes infiltrate around the trabecula. With time extending, coralline hydroxyapatite looks like thin line or thin circle remnant. The degradation sites are filled with renascence bone. Medulla cavity can be seen in the degradation sites. After grafted in body, coralline hydroxyapatite exhibits little local and general abnormal reaction. It conducts good bone fusion of fracture. Coralline hydroxyapatite can be degraded after grafted into body, which is good for remodeling of bone healing. Hence coralline hydroxyapatite is an ideal bone graft substitute of autograft. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009

This paper mainly analysis the control surfaces installed on a spin-stabilized projectile with the purpose of range extension. In order to illustrate the effectiveness of the control surfaces, a full six degree-of-free nonlinear model was built to predict the dynamic behavior of the controlled projectile in atmospheric flight. Compared with the conventional ballistic, the calculation results show that the range extension of a spin-stabilized projectile with control surfaces can be obtained effectively. Parametric analysis about control deflection angle is carried out through deploying the control surfaces at different stages in the atmospheric flight, and another analysis is presented to show the influence to the projectile angle of attack with different ways to deploy the control surfaces. The control surfaces are found to be highly capable for range extension, and the maximum range can be gained during the control surfaces deflection angle deploying at the summit point of the flight trajectory.

TiN metal hard mask (MHM) scheme has become necessary in Cu interconnects when ultra-low k (ULK) materials is introduced. As scale down, the biggest challenge of MHM scheme is how to control the residual stress of TiN layer as the poor mechanical strength of ULK. The deformation (even collapse) of trench structure is found because of the high residual compressive stress in TiN film and Cu voids occur due to the further shrinkage of the feature sizes. In order to solve this issue, a TiN layer with ultra-low compressive stress or even tensile stress is necessary in 20nm and beyond. In this paper, a tensile stress TiN is applied to improve the trench deformation. The results show that MHM scheme using TiN film with tensile stress is a promising technology for 20nm node Cu interconnects and beyond.

This paper reports the Raman scattering analysis of Cu(In,Ga)Se2(CIGS) thin films with Cu/(Ga+In) ratio ranging from 0.748 to 0.982. CIGS thin films were prepared by magnetron sputtering and subsequent selenization process. Frequencies of CIGS Raman peaks do not shift obviously as Cu/(Ga+In) varying around 0.9. Otherwise, the full width at half maximum (FWHM) of the A1 peak reaches its minimum at Cu/(Ga+In) near 0.9 due to better crystallinity and less disorder. Similar phenomena of Raman peaks at 64 cm−1and 72 cm−1were also observed. Since the Cu/(Ga+In) ratio of most high efficiency CIGS solar cells is around 0.9[1,2], the FWHM-Cu/(Ga+In) relationship derived from Raman spectra can be used for non-destructive composition measurement and crystallinity assessment. Furthermore, Cu-poor film shows a broad shoulder at around 150 cm-1 as a result of ordered vacancy compounds (OVC)[3], and Cu-rich film exhibits a peak at around 260 cm-1 corresponding to Cu2Se phase[4].

Using Monte Carlo simulations, we have investigated the classical XY model on triangular lattices of ultra-thin film structures with middle ferromagnetic layers sandwiched between two antiferromagnetic layers. The internal energy, the specific heat, the chirality and the chiral susceptibility are calculated in order to clarify phase transitions and critical phenomena. From the finite-size scaling analyses, the values of critical exponents are determined. In a range of interaction parameters, we find that the chirality steeply goes up as temperature increases in a temperature range; correspondingly the value of a critical exponent for this change is estimated.

A new polishing method shear thickening polishing (STP) was proposed to improve the polishing efficiency in the process to obtain extremely smooth curved surfaces. A non-Newtonian fluid with shear thickening property was utilised as the base fluid of the polishing slurry, in which the abrasives were dispersed. In this study, the influence of polishing speed, abrasive concentration and abrasive size on the surface roughness and material removal rate were investigated by experiments. The experimental results revealed that the polishing speed has the greatest influence on the polishing effect. With the increase of the polishing speed, the material removal rate increases rapidly and smoother surfaces with better roughness can be obtained. Abrasive concentration affects the polishing results in a manner that is similar to polishing speed. Abrasive size seems to have no effect on the surface roughness, but material removal rate increases as the abrasive size decreases. Finally, surface roughness of bearing steel work-piece (O35 mm) was reduced rapidly from Ra = 105.95 nm to Ra = 6.99 nm after one hours' processing under the appropriate conditions.

A polarization controlled switchable multiwavelength erbium-doped fibre laser with overlapping cavities is proposed. The wavelengths are specified by two Bragg gratings in polarization-maintaining PANDA fibre. The proposed laser can be designed to be operated in stable four-wavelength or wavelength switching modes only by simple adjustment of two polarization controllers. For wavelength switching, four single-wavelength, six dual-wavelength, and four three-wavelength operations have been obtained. The minimum wavelength spacing is only about 0.4 nm.

A simple actively mode-locked fibre ring laser is proposed and successfully demonstrated to generate switchable dual-wavelength picosecond pulses using a Bragg grating in a polarization-maintaining fibre. The wavelength spacing specified by the grating is only 0.52 nm. The proposed laser can be made to operate in stable dual-wavelength or switch between wavelengths at room temperature, by simple adjustment of a polarization controller.

The performance of the n-channel Schottky barrier MOSFET with asymmetric barrier height at source/drain (A-SBFET) was numerically simulated. The impact factors on the performance are studied. The results suggest the on-state characteristics of the devices are mainly determined by the source-side barrier height (SBH). Increasing SBH or decreasing body thickness can optimize the sub-threshold slope, and decreasing SBH can enhance the on-state current.

Microporous materials, which refers to the porous materials with pores of less than 2 nm, have been widely used for heterogeneous catalysis, adsorption, separation, gas storage and other numbers of advanced applications. their high-profile application is mainly focused in the field of energy and environment research, such as the storage and separation of hydrogen, carbon dioxide and methane. according to the compositions and structures, common microporous materials include molecular sieves, porous carbon materials, metal-organic framework compounds (mop) and microporous organic polymer (mop). due to the diversity of element components and structure characteristics, the number of the microporous materials, which can be synthesized in principle, is considerably large. it is impossible to study these materials only by means of experimental methods. with the rapid development of computing power and numerical methods, the theoretical methods used in the studies of microporous materials not only provide the material properties at the molecular level, but also reveal the micro-scale experimental mechanism. therefore, it is beneficial for establishing the corresponding relationship between the material structures and their properties, leading to promoting the design and development of novel microporous materials. currently, the accurate theoretical simulations firstly calculate the intermolecular interactions between the key moiety originated from the microporous material and the target molecule through the computational method of quantum chemistry, thereby acquired the potential energy curve of the system. then the van der waals interaction parameters of the force field were fitted. based on the force field, the processes of gas adsorption in the porous materials were simulated by grand-canonical monte-carlo (gcmc) method. good agreements between gcmc simulation results and experimental data for adsorption isotherms and heats of adsorption have been observed in many studies. this paper reviews the theoretical methods recently used in the study of the various microporous materials and the latest theoretical research findings. moreover, the main problems, development prospects and the direction for future research in the study of microporous materials are pointed out.

To prevent gas wells from load-up, it is necessary to study the cause of load-up and condition for liquids to accumulate in wellbore. The paper adopts the view that the liquids droplets entrained in gas wells tend to be flat shape and deduce new formulae for continuous removal liquid from gas wells. The results calculated from the formulae are smaller than that of conventional Turner's. However, the predicted results accord with practical situation of gas wells in China gas fields. In addition, for the easier application purpose, the paper put forward simple formulae from the deduced formulae under analyzing different factors affecting removal liquids from gas wells. The model explains why many gas wells produce without load-up when the producing rate is by far smaller than that of Turner's minimum producing rate. In order to help engineer working in gas fields judge load-up effluence on gas well production, the paper analyzes the production performance of load-up and near load-up as well as unloading gas wells through wellhead producing performance figures.

CdS/CdTe Thin film solar cells are grown in a homemade close-space sublimation system where the cell fabrication of p-n junction is carried out in a continuous, in-line process. The best efficiency achieved is about 11% (AM1.5). Another cell is prepared with the same procedure except for the n-CdS layer coated by sputtering(SP), achieving an efficiency of about 10% (AM1.5). Current density-voltage and external quantum efficiency measurements are analyzed and the solar cell performances are characterized. By the comparison between the practical fitted data and theoretical calculations, the method of improving CdS/CdTe solar cell efficiency, i.e., increasing the open-circuit voltage (Voc), short circuit current (Jsc), and fill factor (FF), is proposed.