Search

As the coal mining depth increases year by year, the deformation and failure of deep roadway become more serious. Therefore, new support equipment with high supporting force and yieldable character is quite necessary for mining safety. In this research, a new mechanical yielding steel prop (MYSP) with high stable load capacity was introduced, which features sustaining large deformation in the field. The test shows that the load capacity provided by doublelayer steel balls is greater than that of single-layer steel balls, and that provided by high-hardness steel balls is higher than that of low-hardness steel balls. When double-layer high-hardness steel balls are adopted, the load capacity firstly increases and then remains stable with the increase of displacement, while it firstly increases and then decreases and finally remains stable with the increase of displacement when double-layer low-hardness steel balls are adopted. The load capacity decreases with the increase of inclined angle of the outer tube, but the influence of the inclined angle of the outer tube on load capacity provided by high-hardness steel balls is small. The load capacity increases gradually with the yielding strength of the prop. Therefore, the MYSP with different load capacities can be designed by changing the yielding strength of the outer tube and inner tube. The field application shows that the MYSP has good characteristics of yielding and high constant resistance. It is very effective for controlling the deformation of surrounding rock mass using the MYSP for roadway pre-support, which also reduces the supporting cost significantly.

Hydraulic conductivity measurement through a fixed wall permeameter is a common practice to obtain the fluid transmissibility characteristics of soil matrix; however, sidewall leakage due to rigid wall effect may significantly influence the observed values for coarse-grained soils. In this study, the boundary flow error was identified through characterizing the geometrical properties of voids adjacent to the sidewall, and a parameter known as the boundary void ratio (eb) was proposed to account for this effect. The findings suggest that a fixed wall cell containing coarse soils would unavoidably generate extra voids at the interface between soil grains and inner rigid wall, contributing to a larger eb at the wall than void ratio within the soil bed; the measured hydraulic conductivity is increased primarily due to the apparatus-induced error. A two-dimensional geometric model was then established to estimate the eb value for uniformly sized coarse soils confined by a rigid permeameter wall, based on which a method was obtained for eliminating the boundary flow error from a fixed wall cell. The mathematical method was finally validated against experimental data from existing literature. It can be concluded that the boundary condition at sidewall featuring unwanted gaps lead to overestimation of the coefficient of permeability; however, the proposed correction method could adequately eliminate the boundary flow error for uniformly sized coarse-grained soils tested within a rigid wall cell.

Hydrogels as typical hydrophilic materials are promising candidates for designing novel functional materials for anti-fouling, oil/water separation, wearable devices, tissue scaffolds, etc. However, it still remains a challenge to design stable and tough hydrogels for applications in complex environments of high stress, temperature, salt, and pH. Herein, we fabricate a novel seawater-enhanced Agar/Poly(N-isopropylacrylamide)/clay hydrogel (APNC gel) through a facile photo-initiated polymerization process. The APNC gel consists of fully interpenetrating double networks with negatively-charged clay serving as physical cross-linkers. The resulting gel exhibits tough mechanical strength (tensile strength of 0.85 MPa and compression strength of 1.68 MPa) and excellent stabilities for high temperature (100 °C) and high salt levels (20 wt% NaCl). Especially, the strength of the APNC gel is greatly enhanced (up to 5.04 MPa) by seawater, which contains numerous inorganic ions (Mg2+, Na+, K+, etc.). Meanwhile, the APNC gel presents excellent anti-adhesion performance due to the negatively-charged clay. Thus, a hydrogel-coated mesh with underwater superoleophobicity has been designed for oil/seawater separation. The resulting mesh can selectively remove oil from seawater with high separation efficiency (up to 99%). These characteristics demonstrate that the tough APNC gel will be an ideal material candidate for developing functional materials applied in a complex environment.

The solid-liquid phase equilibria in the process of producing lithium hydroxide from lithium sulfate at 283.15, 298.15 and 323.15 K were studied via the isothermal solubility equilibrium method, and the solid species, phase diagrams, solution densities and pH were determined. The results show that four solid species of Na2SO4·10H2O, Na2SO4·2.5H2O, Na2SO4 and LiOH·H2O occurred in the system, among them, Na2SO4·2.5H2O was a new solid species not reported in the open literature, which was determined via chemical analysis, Karl Fischer water titration, X-ray diffraction(XRD), thermogravimetic analysis(TG) and differential scanning calorimetry(DSC) testing. Based on the SLE data, one systemic process to produce LiOH·H2O from Li2SO4·H2O was proposed including two crystallization steps at lower and higher temperatures.

In order to develop an iron-based catalyst with high attrition resistance and stability for Fischer–Tropsch synthesis (FTS), a series of experiments were carried out to investigate the effects of SiO2 and its hydroxyl content and a boron promoter on the attrition resistance and catalytic behavior of spray-dried precipitated Fe/Cu/K/SiO2 catalysts. The catalysts were characterized by means of N2 physisorption, nuclear magnetic resonance (NMR), X-ray diffraction (XRD), Raman spectrum, X-ray photoelectron spectroscopy (XPS), H2-thermogravimetric analysis (H2-TGA), temperature-programmed reduction and hydrogenation (TPR and TPH), and scanning and transmission electron microscopy (SEM and TEM). The FTS performance of the catalysts was tested in a slurry-phase continuously stirred tank reactor (CSTR), while the attrition resistance study included a physical test with the standard method and a chemical attrition test under simulated reaction conditions. The results indicated that the increase in SiO2 content enhances catalysts’ attrition resistance and FTS stability, but decreases activity due to the suppression of further reduction of the catalysts. Moreover, the attrition resistance of the catalysts with the same silica content was greatly improved with an increase in hydroxyl number within silica sources, as well as the FTS activity and stability to some degree. Furthermore, the boron element was found to show remarkable promotion of FTS stability, and the promotion mechanism was discussed with regard to probable interactions between Fe and B, K and B, and SiO2 and B, etc. An optimized catalyst based on the results of this study was finalized, scaled up, and successfully applied in a megaton industrial slurry bubble FTS unit, exhibiting excellent FTS performance.

Higher magnetic fields are always favoured in the magnetoplasmadynamic thruster (MPDT) due to its superior control of the plasma profile and acceleration process. This paper introduces the world's first integrated study on the 150 kW level AF-MPDT equipped with a superconductive coil. A completely new way of using superconducting magnet technology to confine plasma with high energy and extremely high temperatures is proposed. Using the PIC method of microscopic particle simulation, the plasma magnetic nozzle effect and performance of the MPDT under different magnetic-field conditions were studied. The integrated experiment used demonstrated that, in conjunction with the superconducting coil, greater homogeneity and a stronger magnetic field not only caused more even cathode ablation and improved its lifespan but also improved the performance of the MPDT (maximum thrust was 4 N at 150 kW, 0.56 T). Maximum thrust efficiency reached 76.6% and the specific impulse reached 5714 s.

Here, we constructed a dual-fluorescence method for the detection of pyrophosphatase (PPase) using pyrophosphate-cerium coordination polymeric nanoparticles (PPi-Ce CPNs) and cadmium telluride quantum dots (CdTe QDs) as signal molecules. The dual fluorescence was achieved by a selective recognition reaction and a coordination polymerization reaction. On the one hand, QDs can selectively recognize Cu2+ and PPi-Cu2+-PPi complexes, which were formed by Cu2+ combining with PPi. On the other hand, Ce3+ can form PPi-Ce luminescent nanoparticles with PPi. Combined with the fact the PPase can hydrolyze PPi to Pi, it is expected to quantitatively analyze PPase, screen inhibitors of this enzyme, and be a clinical marker for hyperthyroidism diagnosis. The strategies with PPi-Ce CPNs and QDs as signal molecules both showed high sensitivity and good anti-interference, and the detection limits (LODs) were 0.15 and 0.8 U L-1, respectively. Analysis of 53 cases of clinical serum samples verified the accuracy and clinical applicability of the method, which showed consistent results in clinical diagnosis (thyroid stimulating hormone, free triiodothyronine 3, and free triiodothyronine 4). In addition, the visual analysis of PPase in 9 samples was successfully realized under UV light using QDs as the signal molecule, and it is easy to distinguish between normal people and hyperthyroid patients. After monitoring and comparing the content of PPase in clinical samples, we recommended 500 U L-1 of PPase as the threshold for diagnosis of hyperthyroidism. Therefore, the dual-fluorescence and visual homogeneous PPase analysis strategy can provide more options for clinical diagnosis of hyperthyroidism, which is expected to achieve point-of-care testing (POCT) for this disease in the future. This journal is

UHVDC wall bushing is one of the key equipments of UHV DC power transmission. The ±800kV SF 6 gas-insulated DC wall bushing has been applied in many China's UHVDC projects. However, ±800kV SF 6 gas-insulated DC wall bushings exposed some problems during operation. In some bushings, flashover discharges occur on the legs of the three-support insulators used to support the conductive rods, and there is evidence of overheating in the butt joint part. Besides, a large amount of aluminum fluoride powder is accumulated on the surface of the conductive rods. In this paper, multiphysics simulation calculations are performed for two typical design structures of ±800kV SF 6 gas insulated wall bushings. The comparison of the electric field strength under four working conditions and stress distribution under the conditions of self weight, wind load, and icing load is given. The results show that the point of maximum electric field strength occurs at the maximum curvature of the shield of the epoxy insulator. The maximum field strength point of the shield cover surface at the flange appears at the R angle. When the structure is changed from three-support to double-support, the maximum field strength of the insulator shield is increased, the maximum surface field strength of the inserts is reduced. The maximum stress of the bushing occurs at the joint between the through-wall cylinder and the hollow composite insulator, and the maximum displacement occurs at the small shield ring at the outdoor end. This paper provides guidance for the structural optimization and operation and maintenance strategies of bushing.

Herein, we rationally designed a dual-functional electroactive filter system for simultaneous detoxification and sequestration of Sb(III). Binder-free and nanoscale TiO2-modified carbon nanotube (CNT) filters were fabricated. Upon application of an external electrical field, in situ transformation of Sb(III) to less toxic Sb(V) can be achieved, which is further sequestered by TiO2. Sb(III) removal kinetics and capacity increase with applied voltage and flow rate. This can be explained by the synergistic effects of the filter's flow-through design, electrochemical reactivity, small pore size, and increased number of exposed sorption sites. STEM characterization confirms that Sb were mainly sequestered by TiO2. XPS, AFS, and XAFS results verify that the Sb(III) conversion process was accelerated by the electrical field. The proposed electroactive filter technology works effectively across a wide pH range. The presence of sulfate, chloride, and carbonate ions negligibly inhibited Sb(III) removal. Exhausted TiO2-CNT filters can be effectively regenerated using NaOH solution. At 2 V, 100 μg/L Sb(III)-spiked tap water generated ∼1600 bed volumes of effluent with >90% efficiency. Density functional theory calculations suggest that the adsorption energy of Sb(III) onto TiO2 increases (from -3.81 eV to -4.18 eV) and Sb(III) becomes more positively charged upon application of an electrical field.

The tungsten–copper composites are widely used in heat sink materials for high power circuits, electrical contact materials, and electrode materials because of their excellent thermal and mechanical properties. We elaborate the Cu-network structured of the W–Cu composites by sintering the intermittently electroplated core-shell powder. After hot-pressing sintering, the W particles dispersed uniformly within the continuous Cu phase. Thus, the bulk of the dense W–Cu composites demonstrated the desired Cu-network structure with high thermal conductivity. No distinct voids were found in the connection between W and Cu. Thermal conductivity increased with the increase of Cu content, and the maximum value was 274.23 W/(m·K). The high sintering density, the Cu-network structure, and the good interface of W and Cu are the main factors ensuring the excellent thermal performance of composites. The maximum values of bending strength (995 MPa) and hardness (240 HV) were achieved with the 20 wt % Cu sample. The deposition process of Cu coating during intermittent electroplating was also discussed.

This work aims to solve the difficulty of V2O5 nanomaterials to exhibit both high specific capacitance and long cycling life as supercapacitor electrodes. Novel 3D V2O5 nanocorals with continuous size-gradient mesopore channels have been constructed by clustering and focusing of V2O5 nanobelt bundles. The 3D V2O5 nanocorals exhibit a specific capacitance as high as 414 F/g at 0.3 A/g. Even after 3000 cycles, the 3D V2O5 nanocorals maintain 70% of initial specific capacitance, which surpasses the cycling lifes of common V2O5 materials. Construction of continuous size-gradient mesopore channels is proven to be effective strategy to simultaneously enhance the specific capacitance and cycling life of V2O5 materials. This work has provided new insights into the design and preparation of soluble transition-metal based nanomaterials for high performance supercapacitors.

Microscale crosslinked polymeric hydrogels, termed microgels, have attracted considerable attention as enhancing oil recovery (EOR) agents due to their favorable in-depth fluid diversion effect. However, the oil/water interfacial behavior of microgels remains unclear, limiting the comprehensive understanding of the EOR mechanism. In this study, the oil/water interfacial behavior of microgel powder (MP) and microgel emulsion (ME) was studied through emulsification tests and interfacial tension (IFT) measurements. Despite the similar properties of the microgel particles, such as morphology, size distribution and zeta potential, ME exhibited better emulsification performance than MP in deionized (DI) water due to the presence of additional surfactants in ME. However, since the competitive adsorption between the microgel particles and surfactants on the oil/water interface changed with salinity, ME exhibited a higher emulsion volume but lower emulsion stability than MP in brine. Moreover, W/O and O/W emulsions were formed in DI water, but only an O/W emulsion was formed in brine for ME. Furthermore, MP exhibited better IFT reduction performance in brine due to the weaker steric hindrance and tighter adsorption layer on the oil/water interface. In contrast, ME showed better IFT reduction performance in DI water owing to the interaction between the microgel particles and the surfactants. Considering that MP is usually used in the laboratory while commercial microgels are provided in the form of ME, the different oil/water interfacial behaviors of MP and ME may result in an inconsistent understanding of the EOR mechanism in laboratory study and field application.

Hydrocarbons transportation on the sea bed using pipelines are prone to clogging due to gas hydrates formation. The formation happens in the high pressure and low temperature condition. Currently, operators are using thermodynamic hydrate inhibitors which are costly due to the large volumes consumed and not environmental friendly. Researchers are now extensively studying on the Kinetic Hydrate Inhibitors (KHI) from different sources that is more cost effective due to small volume consumed and more environmental friendly. In this paper, it focuses on natural polymers derived from fruit peels, table sugar and stevia as possible KHI. The objectives are to find the optimum concentration of natural polymers in delaying the nucleation of natural gas hydrates by measuring the induction time using high pressure micro-differential scanning calorimeter. The results show sugar has a great potential as KHI as the induction time for methane hydrates is delayed to 82 and 77 minutes at 50 and 70 bars respectively.

In order to explore the hydration conditions of quartz powders at room temperature, pastes containing quartz/lime at a ratio of 4:1 were prepared at a water/cement ratio of 0·4. The effect of mechanical grinding on the hydration activity of quartz was investigated based on determination of the compressive strength, the mineral phase composition, calcium hydroxide consumption and the quartz reaction degree of hardened samples of quartz/lime pastes under standard curing conditions (temperature of 20 ± 1°C and mass of 95%). The results revealed that grinding had an observable impact on the hydration activity of quartz. The compressive strength of the quartz/lime pastes increased from 0·34 MPa to 1·59 MPa after a curing period of 140 d, and the specific surface area increased from 227·2 m2/kg to 729·1 m2/kg. Moreover, a small amount of CSH gel was detected in the test pastes. This indicates that quartz has the capacity to react with calcium hydroxide and shows some pozzolanic activity at room temperature under mechanical activation and after a long curing period.

In this paper, a discrete and continuous body coupling algorithm is used to study the dynamic contact characteristics between ballasts and between ballasts and track structures. Firstly, the three-dimensional fine modeling of ballast particles is realized based on the three-dimensional laser scanning method, and then through the discrete and continuum coupling algorithm from the micro-macro point of view, a multiscale and unified particle-track structure coupling model is established. Based on the coupling model, the macro- and microdynamic characteristics of the ballast bed and the mechanical characteristics of the track structure under the dynamic load of high-speed trains with different driving speeds are studied. It is shown that the cumulative settlement of the ballast bed is directly proportional to the contact force and rotation speed of the ballast, and the faster the driving speed is, the greater the cumulative deposition speed and cumulative settlement of the ballast are. The contact force between the ballast and sleeper mainly comes from the bottom of the sleeper, and its contact force and contact strength increase with the increase of driving speed.

A modified 1/ $f$ noise model has been proposed for MOSFETs with an ultra-thin gate oxide layer. It is revealed that as the gate length $L$ deceases, the normalized drain current noise spectra density also decreases, which does not coincide with the regular 1/ $f$ noise theory. It is found that the trap-assisted gate leakage affects the drain current 1/ $f$ noise, and for the first time, it is demonstrated that the equivalent oxide trap density, the free carrier density, as well as $L$ determine the 1/ $f$ noise. A modified quantitative model is then proposed, which can well predict the 1/ $f$ noise.

Novel hydrangea-like VS4 nanomaterials as high-performance electrode materials of supercapacitors were successfully synthesized by hydrothermal method using Na3VO4 · 12H2O2, citric acid and TAA (thioacetamide). The prepared samples were characterized by XRD, SEM and BET, CV (cyclic voltammetry) and GCD (galvanostatic charge and discharge). The results revealed that VS4 are hollow microspheres with a diameter of ~5 μm and made of nanosheets, the microspheres formed from diffusion growth of solid microspheres. These materials exhibited a tremendous specific capacitance of 533 F/g, at 0.1 A/g in the potential range of −0.9 to 0 V when used as supercapacitor electrodes in a solution of 1 M Na2SO3. The energy density is as high as 60 Wh/kg, which is much higher than those of many other symmetrical supercapacitors. In addition, the capacity retention of 80% was achieved even after 500 cycles, demonstrating the high performance of vanadium oxide nanomaterials used in supercapacitors.

Glass seal is an important process in diode package technology. In order to reach a relatively high temperature, graphite is widely used as its excellent performance in electrical conductivity, thermal conductivity and easy forming. In this paper, the boat could be divided into working zone and tuning zone. The structure of tuning zone is researched through the method of thermal-electric couple. Thermal gradient and dispersion were different in different structural design. By compared the temperature data of fifteen points in working zone under computer simulations and testified by glass seal experiments, the temperature optimism abilities of three types of tuning structures of are discussed. A better structure of glass seal graphite boat is designed.

An effective method for ingot quality control in directional solidification by using artificially designed quartz coating as seed is demonstrated in this paper. Quartz powders sprayed at the bottom of the crucible provided numerous nucleation points for the silicon grain growth. The quartz seeded growth ingot showed a large number of small and uniform silicon grains at the bottom, although the grain size increased with crystal growth. Comparatively less dislocation agglomerates and multiplication rate through bottom to top were observed through photoluminescence (PL) analysis. Crystals produced by quartz seeded method showed a higher and more uniform minority carrier lifetime distribution compared to that produced from normal method without seed, and shorter low lifetime area length at the bottom compared to that produced from mc-Si seed-assisted growth method, indicating larger production yield under the same feedstock charging weight. An enhanced average solar cell conversion efficiency of as high as 0.52% in absolute value was obtained compared to that made from seedless method under the same cell manufacture process line, very close to that made from mc-Si seed-assisted growth method.

Scale effects are studied on the buckling behavior of bilayer composite plates under non-uniform uniaxial compression via the nonlocal theory. Each isotropic plate is composed of a material that is different from others, and the adhesive between the plates is modeled as the Winkler elastic medium. According to the symmetry, effects of the Winkler non-dimensional parameter, the thickness ratio, the ratio of Young’s moduli, and the aspect ratio are also considered on the buckling problem of bilayer plates, where only the top plate is under the uniaxial compression. Numerical examples show that the Winkler elastic coefficient, the thickness ratio, and the ratio of Young’s moduli play decisive roles in the buckling behavior. Nonlocal effect is significant when the high-order buckling mode occurs or the aspect ratio is small.

With the rapid development of integrated photonics, expensive and bulky commercial spectrometers force people to make more efforts to investigate high-performance, integrated and low-cost spectrometers. Spectrometers benefiting from the complementary metal-oxide semiconductor (CMOS) technology have greatly enriched the applications of spectrum detection while devices based on optical fibers still have potential development room. Owing to the strong dependence of multimode interference on wavelength generated in a multimode fiber, probe signals of arbitrary spectra could be detected by a detector array integrated on the top and reconstructed by using a compressive sensing (CS) algorithm. The CS algorithm has been widely used in signal processing, which saves more computing storage and time but maintains the same precision. With the interference pattern system, our spectrometer based on a fiber taper achieves a spectral resolution of 20 pm (one order of magnitude better than commercial spectrometers) and a detection bandwidth of more than 200 nm on a device length of 1 mm. After optimizing the energy function, the spectral reconstruction results show excellent detection capability and metamerism effect superior to RGB cameras or human eyes, providing a significant role for portable multi-functional on-chip systems in future.

boron carbide–cerium boride porous composites are prepared by hot pressed sintering, and mechanical properties and microstructure of boron carbide–cerium boride porous composites were tested. The results show that Flexibility strength of B4C-CeB6 porous composites is greatly improved compared with that of monolithic porous boron carbide. B4C react with CeO2 to completely form CeB6 in porous composites. CeB6 particles in B4C grain boundary are produced by in-situ reaction. The presence of CeB6 reinforcing particles could also suppress growth of B4C grains which normally leads to improved strength.

B4C-CeB6 porous composites are prepared by hot pressed sintering between 1900°C and 2000°C, and mechanical properties and phase composition of B4C-CeB6 porous composites were tested. The results show that the porous rate of B4C-CeB6 porous composites ranges between 30%-48% at sintering temperate 1900°C-2000°C. Porous rate of B4C-CeB6 porous composites is decreased with temperature be increased. Flexibility strength of B4C-CeB6 porous composites is greatly improved compared with that of monolithic porous boron carbide. B4C react with CeO2 to completely form CeB6 in porous composites.

Firstly, this paper introduces the development of amorphous alloy transformer. According to the technical characteristics of amorphous alloy transformer and the application of Jiangsu power, the comprehensive evaluation about amorphous alloy transformer from the safety performance, the economic performance and the environmental impact are studied comparing with S11 type, S13 type and S15 type transformer. In the safety performance, overload capacity and over-excitation ability of amorphous alloy transformer is insufficient; in the economic performance, low no-load loss, high efficiency, energy saving effect of amorphous alloy transformer is obvious; in terms of environmental impact, the audible noise level of amorphous alloy transformer is higher than that of conventional transformer, and manufacturers need to study to reduce the noise level. Finally, the application recommends of amorphous alloy transformer is presented based on comprehensive evaluation.

The collagen fiber/CaCO3 hybrid materials were successfully prepared via in situ organic-inorganic hybrid technique. The surface morphology, hybrid mechanism, thermal and hydrothermal stability of these materials were investigated, respectively. Scanning electron microscopy (SEM) analysis showed that the size scale and distribution of CaCO3 particles in collagen fiber relied on the concentration of CaCl2. When the CaCl2 was at low concentration, for example 6 wt%, the in-situ produced CaCO3 particles were distributed evenly around the collagen fiber, the particle size could be controlled in the range of 2–4 µm and no apparent coagulation of CaCO3 particles was found. Fourier transform infrared spectroscopy (FTIR) study revealed the interactions between the collagen fiber and CaCO3 particles. The water solubility test and TGA analysis indicated that the solubility of collagen fiber in hot water decreased significantly after hybridization with CaCO3 particles, whereas, the decomposition temperature was improved with increasing of the production of CaCO3 particles. Moreover, the hybrid materials were used in conjunction with polyurethane and CaCO3 powder to fabricate a novel synthetic paper. The result showed that the synthetic paper had good writing and printing.

The TiSi x /n-Si(100) Schottky power diode is fabricated by Ti silicidation, and the Schottky barrier height (SBH) is found to be $\sim 0.69$ eV. For the first time, it is demonstrated that an 80 meV SBH reduction can be achieved by a TiN capping layer, which can lower $\sim 15$ % self power consumption of the diode at a forward current of 20 A. It is revealed that the nitrogen atoms’ diffusion into the TiSi x results in the SBH lowering, which is discovered by X-ray diffraction measurement, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy.

Liquidus temperature, electrical conductivity and phase composition of Al2O3-CaO-SiO2-CaF2-MgO slag system were studied. The results showed that the liquidus temperature of the slag decreased with increasing MgO content, and its electrical conductivity increased with increasing MgO content and temperature. When the content of MgO is 5 %, the main phase compositions of the slag are composed of MgAl2O4, Ca2SiO2F2, CaAl4O7 and Ca5Al6O14. When the content of MgO is 7 %, the main phase compositions of Al2O3-CaO-SiO2-CaF2-MgO are composed of MgAl2O4, Ca4Si2O7F2, CaAl4O7 and Ca5Al6O14.And the content of MgAl2O4 and Mg2SiO4 increased with increasing MgO.

The properties of CeO2-LaB6/B4C composite material prepared by hot pressed sintering method was tested, CeO2as a sintering aid for boron carbide is investigated in this paper. The study shows: the hardness of CeO2-LaB6/B4C composite increases with the content of CeO2. The density, hardness, flexibility strength and the fracture toughness of LaB6/B4C composites is greatly improved compared by CeO2additive. When the content of the CeO2is 1wt%, LaB6/B4C composite has its the best mechanical properties. The density reaches its supreme value of 2.676 g/cm3, the hardness reaches its supreme value of 39.19 GPa, the flexibility strength reaches its supreme value of 354.15 MPa and the fracture toughness reaches its supreme value of 5.15 MPa.m1/2. In conclusion, the density, hardness and flexibility strength of LaB6/B4C composite is improved by CeO2additive. However,it gives little effect on fracture toughness of LaB6/B4C composite. The main fracture way of CeO2-LaB6/B4C composite material is intercrystalline rupture, while the transcrystalline rupture is minor.

Alumincoating was prepared on a Ni-Cr-W-Al nickel-base superalloy by pack cementation, the effects of Al content and aluminizing temperature on coating formation were investigated. Coating microstructures were investigated using optical and scanning electron microscopes, EDS and X-ray diffraction (XRD) techniques. The results showed that the coatings prepared at 800°C in the powders with 15%, 30% and 99% Al were different. NiAl3 coating was obtained in the conditions of aluminizing temperature of 700°C, 750°C, 850°C and of Al content of 99%.

PurposeThe purpose of this paper is to provide a new entry board for drilling holes on the PCBs, superior in heat removal effect, lubricating effect and hole locating effect in forming holes, resulting in an excellent process of forming holes with a high quality.Design/methodology/approachWith the mixture of PEG, PEO and adhesive used as endothermic and lubricant resins and aluminium foils used as baseplates, a series of coated and aluminous entry boards (CABs) for PCB drilling were successfully prepared. Scanning electron microscopy (SEM) was employed to observe the surface appearance of the entry boards. The endothermic and lubricant effect of the resin applied on the CABs was characterized by differential scanning calorimetry (DSC) and polarizing microscope (POM). Moreover, the CABs' good drilling properties were tested when they were used for PCB drilling.FindingsFrom the result of SEM analysis, it was found that compared to the common aluminium foil, the surfaces of the CABs were smoother and flatter, which could improve the hole location accuracy and reduce the drill breakage. By means of the DSC and POM, the endothermic and lubricant effect of the CABs was proved. The crystalline substances (PEG and PEO) in coated resin could absorb the heat of the drill bit from heat generation and lubricate it through the phase transition of they own when a hole was being made, which could give high‐quality holes with good production efficiency. The drilling tests showed that due to the endothermic and lubricant resins, the CABs were superior to the common aluminium foil, not only in hole location accuracy, but also in hole wall quality and protection of a drill bit.Originality/valueThis paper has a remarkably high industrial practicality in the PCB manufacture process.

The effects of different pure Al compositon in the pack powder on aluminide coating formation of a new kind of Ni-Cr-W-Al nickel-base superalloy by pack cementation aluminizing was investigated. The content of pure Al powder is 15% and 30% in the aluminizing agent. The microstructure and phase composition of diffusion coating was studied.

Fluorescent core/shell CdTe@SiO2particles were prepared via reverse microemulsion method. When all the other parameters were kept constant, a simple linear relation was deduced to describe the connection between SiO2shell thickness and volume of tetraethyl orthosilicate(TEOS). The results indicated that linearity and morphology of CdTe@SiO2were better when the volume of TEOS ranged from 5μl to 200μl. Nevertheless, further decreasing the volume of TEOS to 2 μl led to a poor spherical regularity and if the volume of TEOS was larger than 200μl, size changes of CdTe@SiO2were no more clear because of restrained size of water pool

The mechanical properties of B4C-CeB6 composite prepared by hot pressed sintering method were tested. The study shows: the hardness of B4C-CeB6 composite increases with the content of cerium boride. When the content of the cerium boride is 4wt%, the hardness reaches its supreme value of 31.98Gpa，its hardness is improved nearly 21.09% compared to monolithic boron carbide. The content of the cerium boride does not affect greatly on flexibility strength. However，it gives much effect on fracture toughness. When the content of the cerium boride is 4wt%, the fracture toughness reaches its supreme value of 5.06MPa.m1/2, which is improved nearly 37.5% compared to monolithic boron carbide materials. The main fracture way of B4C-CeB6 composite is intercrystalline rupture, while the transcrystalline rupture is minor. It appears that this change of fracture mode gives rise to the improvement of the fracture toughness.

B4C-CeB6/Al composite was fabricated by pressureless infiltration technology. It is composed of the phases of Al, B4C, AlB2, Al3BC and CeB6, and Al4C3 is not found because of the existence of CeB6. It could identify that AlB2, CeB6, and Al3BC were formed as interfacial reaction products. Al3BC is formed on the interface of B4C and Al; therefore it connects the aluminum with the ceramic toughly. AlB2 as strip crystal is formed between B4C and Al, which has higher fracture toughness.CeB6 particles in B4C grain boundary are discovered by TEM, which caused intercrystalline rupture. Grain toughening and reinforcing, crack deflection, crack bridging is the main toughening and reinforcing mechanisms of B4C-CeB6/Al composites.

Liquidus temperature, electrical conductivity and phase composition of Al2O3-CaO-Na2CO3 slag were studied in the paper. The results showed that the minimum value of liquidus temperature was 1429°C when the content of Na2CO3 was 11%. The Al2O3-CaO-Na2CO3 slag of lower liquidus temperature had higher electrical conductivity, and the electrical conductivity of Al2O3-CaO-Na2CO3 slag increased with the increase of temperature. The main phases of Al2O3-CaO-Na2CO3 slag are composed of CaAl2O4, Ca3Al10O18, NaAlO2 and Na2CO3. The addition of Na2CO3 is to be more effective for decreasing liquidus temperature and increasing electrical conductivity in the Al2O3-CaO-Na2CO3 slag system.

Liquidus temperature, electrical conductivity and phase composition of Al2O3－CaO－SiO2－CaF2 System were studied. The results showed that the liquidus temperature of the slag decreased with increasing CaF2 content, and its electrical conductivity increased with increasing CaF2 content and temperature. When the content of CaF2 is 20%, the liquidus temperature is 1469°C. When the contents of CaF2 is 10%，its main phase compositions are composed of Ca5Al6O14、Al2Ca3(SiO4)3、Al2(SiF6)3 and Ca3Al10O18. Ca2AlF7、Ca2Al3O6F becomes more and more with increasing the content CaF2 because of F1- replacing O2- in molten slag.

A series of Al2O3@FDU-14 composites with different alumina loadings were prepared using a solid state grinding method. The 4% Pt catalysts supported on Al2O3@FDU-14 were prepared by impregnation using H2PtCl6. X-ray diffraction, transmission electron microscopy, and nitrogen adsorption characterization of the Pt/Al2O3@FDU-14 catalysts indicated that the mesoporous features of the FDU-14 mesopolymer were retained. The Pt/Al2O3@FDU-14 catalysts were used in the asymmetric hydrogenation of ethyl pyruvate after they were chirally modified with cinchonidine. For Al2O3 loading from 5% to 15%, Al2O3 was uniformly dispersed inside the mesoporous channels of FDU-14 host. Ethyl pyruvate conversion and their ee values increased with increasing alumina loading, with a highest ee value of 80%. It was suggested that the alumina coating inside the mesoporous channels of FDU-14 decreased the surface electronic density of the FDU-14 mesopolymer so that cinchonidine can be easily adsorbed on the surface of Pt/Al2O3@FDU-14 catalysts. As compared with chirally modified Pt/FDU-14 catalysts, chirally modified Pt/Al2O3@FDU-14 catalysts gave higher ee values.

Liquidus temperature, electrical conductivity and phase composition of Al2O3 -CaO-CaF2 slag system were studied. The results showed that the liquidus temperature of the slag decreased with increasing CaF2 content, and its electrical conductivity increased with increasing CaF2 content and temperature. The liquidus temperature is 1468°C when the content of CaF2 is 20%. Its phase composition are composed of CaAl2O4、Ca2Al3O6F、Ca2AlF7 andAlF3. When the content of CaF2 is 10%, there are lots of CaAl2O4. The content of CaAl2O4 decreased with increasing CaF2, but the content of Ca2Al3O6F and Ca2AlF7 increased.

Based on the deformation features in the rolling process of shaped wires, this paper focuses on the metal flow rules and distribution characteristics of stress and strain through simulating the shaping process by DEFORM-3D. The equivalent stress and equivalent strain is in the same distribution: smallest on the base and gradually increasing along the broadening direction and highest on the tooth. A satisfactory concordance between the scattering of the hardness values measured over the wire sections and that of the equivalent strain is found, thus verifying the accuracy and the reasonableness of the simulation process.

Heating energy consumption of rural buildings in China was analyzed in this paper. Thermal insulations were compared between some kinds of biomass and fossil materials. Application forms of biomass materials were discussed for heat insulation in rural buildings, and the potential was analyzed for energy-saving and CO2-emission-reducing. As a big agricultural country, the benefit and potential of biomass materials may be remarkable in heat insulation in rural buildings in the light of local conditions.

Hydrophobic polyhydroxyalkanoate (PHA) scaffolds made of a copolyester of 3-hydroxybutyrate-co-hydroxyhexanoate (PHBHHx) were coated with a fusion protein PHA granule binding protein PhaP fused with RGD peptide (PhaP-RGD). Human bone marrow mesenchymal stem cells (hBMSCs) were inoculated on/in the scaffolds for formation of articular cartilages derived from chondrogenic differentiation of hBMSCs for cartilage tissue engineering. PhaP-RGD coating led to more homogeneous spread of cells, better cell adhesion, proliferation and chondrogenic differentiation in the scaffolds compared with those of PhaP coated or uncoated scaffolds immerging in serum minus chondrogenic induction medium. In addition, more extracellular matrices were produced by the differentiated cells over a period of 14 days on/in the PhaP-RGD coated scaffolds evidenced by scanning electron microscopy imaging, enhanced expression of chondrocyte specific genes including SOX-9, aggrecan and type II collagen, suggesting the positive effect of RGD on extracellular matrix production. Furthermore, cartilage-specific extracellular substances sulphated glycosaminoglycans (sGAG) and total collagen content found on/in the PhaP-RGD coated scaffolds were significantly more compared with that produced by the control and PhaP only coated scaffolds. Homogeneously distributed chondrocytes-like cells forming cartilage-like matrices were observed on/in the PhaP-RGD coated scaffolds after 3 weeks. The results suggested that PhaP-RGD coated PHBHHx scaffold promoted chondrogenic differentiation of hBMSCs and could support cartilage tissue engineering.