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Exploring the hydrophobicity of robust conductors is significant for electronic devices to simultaneously be used in a wet environment and extreme conditions. However, a combination of conductivity, strong mechanical properties, and hydrophobicity in one material is hindered by the inherent features of the materials. A new kind of robust hydrophobic conductor is designed in transition-metal diborides (TMdBs: TiB2, ZrB2, and HfB2) to break through this challenge. The results calculated by density functional theory indicate that high hardness comes from high shear and bulk modulus, which is consistent with experimental results (TiB2, 25.0 GPa; ZrB2, 17.5 GPa; HfB2, 21.5 GPa). The theoretical calculated results reveal that edge sides have a lower surface energy than basal plane (001) in TMdBs. Hence, the edge sides are exposed with a needle-like morphology in TMdBs. Moreover, needle-like surfaces exhibiting hydrophobicity have water contact angles of 132.0° (TiB2), 116.8° (ZrB2), and 114.0° (HfB2). The hydrophobicity arises from a lower surface free energy of edge sides in TMdBs and a rough surface that reduces the contact area of water and a solid. This work develops a new kind of robust functional material in TMdBs.

Hot compression behaviors of CrCoNi medium entropy alloy are were performed on the Gleeble-3800 thermal simulator in the strain rate range from 0.01 to 10 s−1 and the temperature range from 800 to 1100 °C. According to the true stress-true strain curves, the true stress decreases with the decreasing of strain rate and the increasing of deformation temperature. The experimental parameters were fitted, and a modified model based on Arrhenius hyperbolic sine was established. Among them, material constants such as, n, A, and Q are functions of strain. Meanwhile, the processing map of CrCoNi medium entropy alloy under different strain conditions are established. Importantly, the optimal domain of apparent flow stability can be determined as the deformation temperature from 900 to 1100 °C and the strain rate from 0.01 to 10 s−1. The results indicate that the stability domain of the CrCoN medium entropy alloy has a wider range, and the strain has little effect on its processing performance.

In this article, an autotransformer coil for domestic IH adopting single-ended resonant inverter (SE-IH) is proposed. The proposed SE-IH can simultaneously meet the impedance requirements of ZVS and high induction efficiency at a higher frequency, resulting in a higher efficiency, increased output power and improved compatibility with nonferromagnetic vessels. Based on the proposed accurate wide-frequency impedance model of the coil-vessel system, the induction efficiency of the proposed SE-IH is analyzed, as well as the impedance condition for ZVS. The selection of the operating frequency and the design of the proposed coil for induction efficiency optimization are then given. Finally, a prototype of the proposed domestic SE-IH is fabricated, achieving 2269-W output power with 99.26% induction efficiency for GB45 steel vessel and 932-W output power with 90.46% induction efficiency for aluminum vessel.

Maize grain have a high moisture content in the harvest period, and a model to calculate the JKR surface energy between high-humidity maize grains was developed. A system was designed and used to measure the contact angle. The effects of different factors on the JKR surface energy were investigated. The results showed that the JKR surface energy of maize grains increased with increasing moisture content and temperature. The content of crude starch in grains is the main factor that affects the JKR surface energy. The JKR model and no slip model of EDEM were used to simulate the collision of high-humidity maize grains, and the results were compared with the physical tests. The data obtained by the JKR model are compared with those obtained by Young model and OWRK model. The results provide a reference for the calculation of the JKR surface energy of other particles with high moisture content.

Ti doped DLC coating was deposited on ductile iron disk commonly used material in small Wankel rotary engine. The friction coefficient under the working condition of apex seal was investigated. The results show that the Ti doped DLC coating is of low friction coefficient. In addition, the surface hardness and the morphology were improved by Ti doped DLC coating. After that, the Ti doped DLC coating was deposited on the housing. A performance testing platform for small Wankel rotary engine was built. The effect of Ti doped DLC coating under motored and working conditions were measured. The results show that when the operation speed varies from 7 000 to 17 000 r/min, the friction loss between apex seal and Ti doped DLC coating ranges 15~38 W under motored condition. It is only 68% of the friction loss between apex seal and ductile iron. Under working condition, the coating increases 23~78 W of the engine output power, which can improve the output power of small Wankel rotary engine by 24%~43%.

The experiment results of double dielectric barrier discharge reactor (DDBD) and pulsed corona discharge reactor (PCD) show that the optimal operating frequency of DDBD is 10kHz, the operating power is 0.5~2.1kW, but the optimal operating frequency of PCD is 1600Hz, operating power is 1~4.8kW. PCD reactor is more suitable for deodorization device because of wider operating power and operating voltage, it’s easy to control electric field intensity in appropriate value, better adapt to the working environment. The activated carbon adsorption device was set at the tail of PCD and applied in sewage pumping station, and better deodorization effect is obtained. Ozone escape is controlled in the prescribed range while filtering granular pollutants to avoid the formation of secondary pollution. Pulsed corona discharge plasma deodorization technology has the advantages of good deodorization effect, controllable ozone escape and flexible operation. With the development of power supply technology, the process cost is gradually reduced, so it has good market application value.

Phase change heat transfer in nanoporous shape-stabilised phase change materials (ss-PCMs) is of great importance for the efficient utilization of novel energy storage materials. However, the lack of thermodynamic properties hinders the study on phase change heat transfer. In this paper, we selected the binary chloride salts (NaCl–KCl), the promising high-temperature energy storage materials for concentrating solar power, and computed their melting point using the molecular dynamics method. This study not only provides the most fundamental thermal information for the study on phase change heat transfer but reveals the mechanism of the size dependence of melting point from the aspect of the atoms. It is found that the ions in small nanoclusters vibrate more intensely and the crystal structure is easier to be destroyed, leading to lower melting point. The ion self-diffusion coefficient is also computed and analysed from the local microstructure; and it is found that the coefficient is not affected remarkably by the component and the size of nanoclusters.

Due to the low temperature and complex composition of the flue gas of the cremators, there is no effective denitration process for cremators flue gas in the industry, combining the advantages of high voltage narrow pulse discharge technology, plasma generation technology and spray absorption technology, the experiments were carried out on a cremator. The results show that the corona discharge plasma technology can purify the flue gas of the cremator very well. Under the conditions of 26KW injection power, 0.1% NaOH and 7L/m3 spray gas ratio, the desulfurization rate is over 85% and the denitration rate is above 60%. With the gradual improvement of environmental emission standards, the process can be optimized by adding reductants or accelerators, and the ultra-low emission of cremator can be gradually realized.

Mg-11Gd-2Y-0.5Zr(wt.%, the same below) alloy was prepared by vacuum induction furnace. The creep behavior of the alloy at 200–270 °C/110-150 MPa was studied. Constitutive equation of steady state creep rate was constructed. The evolution of precipitated phases in α-Mg matrix and grain boundary before and after creep was analyzed by high resolution transmission electron microscopy (HRTEM). The results show that Mg-11Gd-2Y-0.5Zr alloy has excellent creep resistance. The steady state creep rate increases with the increase of stress and temperature. The steady state creep rate is only 7.75 × 10 −9 s −1 at 270 °C/130 MPa. The average stress exponent and creep activation energy are 3.62 and 40.3420607 kJ/mol, respectively, at 200–270 °C/110-150 MPa. The creep mechanism is mainly dislocation slip and grain boundary slip. The fine β′ phase in the α-Mg matrix coarsens gradually and becomes elliptical, triangular distribution and interconnection. The β′ at grain boundary evolves into the equilibrium phase β. There is precipitation free zone (PFZ) on the side of grain boundary due to the sliding of grain boundary.

To solve the failure of hub bearings, a Semi-simplified finite element method (FEM) is proposed to study the sealing performance based on the rigid-flexible combined seal groove. The impact of compression ratio, seal groove geometry, O-ring material hardness and O-ring inner-diameter on Von Mises stress and contact pressure is studied with the FEM. The results indicate that the designed sealing mechanism with the optimized parameters can meet the sealing requirement. The Semi-simplified FEM is effective to study the rigid-flexible combined seal groove. Compression ratio and O-ring material hardness have a vital influence on the sealing performance. The relationship between the maximum operation pressure and the compression ratio is validated with the dynamic oil injection test.

Novel Ti-Cu-O nanotubes with the diameter of approximately 22 nm, the length of about 360 nm and the wall thickness of approximately 6 nm, were in-situ fabricated by one-step anodic oxidation of Ti60Cu40 amorphous alloy in the ethylene glycol containing F-. The Ti-Cu-O nanotubes exhibited superior electrocatalytic performance for glucose oxidation with an ultrahigh sensitivity of 403.9 μA cm-2 mM-1 in a linear range covering from 10 μM to 0.2 mM and low detection limit of 1.40 μM (at signal/noise ratio (S/N) = 3) at the potential of 0.6 V (vs. SCE). Moreover, the Ti-Cu-O nanotubes demonstrated a long-term stability and a good selectivity to uric acid and ascorbic acid. The superior catalytic performance of Ti-Cu-O nanotubes is attributed to the synergistic effect of Cu species existence in different valences and the tubular microstructure with large specific area. All results suggest that the Ti-Cu-O nanotubes could be potential materials for non-enzymatic glucose sensor.

The aim of this paper is to study effect of DLC coating on the friction power loss caused by apex seal in small Wankel rotary engine. A numerical model which is capable of evaluating the lubrication state under mixed lubrication is built. The involved parameters of DLC coating are obtained through experiment. Then, the effect of DLC coating is numerically investigated and validated by experimental result. Results show that the friction power loss for DLC coated surface is about 55% of that for uncoated surface. It is partly attributed to the low friction coefficient of DLC coating. Besides, the normal force of asperity is decreased by DLC coating. It is also conducive to the reduction of the power loss.

A detailed nondestructive analytical method for quantitative food analysis was established by using a self-fabricated NIR-LED light source combined with Mg3Ga2GeO8 (MGGO) phosphor and a blue LED ch...

Mg–11Gd–2Y–xSm–0.6Al (x = 0, 1, 3, 5) alloys were prepared in electromagnetic induction furnace by gas protection. The crystal structure, microstructure and mechanical properties of as-cast Mg–11Gd–2Y–xSm–0.6Al alloys were studied by X-ray diffraction, metallographic microscope, scanning electron microscopy and tensile testing. The results show that the main phases of Mg–11Gd–2Y–xSm–0.6Al alloys are α-Mg matrix, Mg5Gd, Mg24Y5 and Mg41Sm5. The addition of Sm refines the microstructure and increases the number of second phase in the grain boundary. The diffraction peaks of the cylindrical plane (100)α-Mg, base plane (002)α-Mg and conical plane (101)α-Mg are shifted to a low angle. The offset of diffraction peak and the lattice constant of α-Mg increase with the increase in Sm content. The crystal axis ratio decreases with the increase in Sm content. When the addition of Sm is 3%, the ultimate tensile strength reaches to 240 MPa, which increases by 17.07%. The improvement in mechanical properties is mainly attributed to the grain refinement and the decrease in the crystal axis ratio of α-Mg.

We conducted experimental measurements to examine the upward oil-water flow patterns in a vertical pipe (0.02 m I.D.) under high temperatures up to 130 °C and high pressures up to 20.51 MPa. The viscosity of the oil sample was 85.113 mPa·s at 40 °C. All the experiments were conducted with an in-house-built high pressure/temperature flow apparatus. This apparatus is equipped with a view window that allows us to visually observe the upward flow patterns of oil-water two-phase flow in a 0.02 m I.D. stainless steel pipe. The effects of pressure, temperature, input water fraction (IWF) and mixture flow rate on the flow patterns and friction pressure gradients were systematically investigated. We plot the observed flow patterns on a flow pattern map in which input water fraction was used as the y-axis and the mixture flow velocity was used as the x-axis. Based on the measurement results, we observed nine flow patterns including four water-in-oil flow, transition flow and four oil-in-water flow patterns. With an increase in temperature at a given input water fraction, slug flow, plug flow with large water drops tended to transform into bubbly flow and dispersed flow with smaller water drops, water-in-oil very dense bubbly flow (VDB W/O) was observed at high temperature due to the significantly increasing of in-situ water holdups. The transition flow and the boundaries in the flow pattern maps tend to occur at lower input water fraction values. The effect of pressure on the flow patterns was found to be opposite to that of temperature. The possible causes leading to the changes in the flow patterns subjected to pressure/temperature variations were provided in terms of changes in density ratio, interfacial tension, and viscosity ratio between oil and water. The phase inversion points at different temperatures and pressures reflected from friction pressure gradients were found to be in agreement with the results of flow patterns. This work contributes to a better understanding of oil-water two-phase flow behavior under high temperature/pressure.

In this work, an airtight solid-state strategy was developed for the synthesis of K2TiF6:Mn4+ phosphor without the usage of high concentration HF solution. By heating K2TiF6, K2MnF6 and KHF2 in a sealed container at 474 K for hours and then washing the as-synthesized samples several times, K2TiF6:Mn4+ phosphor was obtained. The microstructure, luminescent properties of the phosphor were investigated systemically. The reaction mechanism were investigated and discussed in detail. KHF2 is the key role to obtain the red phosphor, which provides additional pressure and HF gas atmosphere, works as reaction intermediate and contributes to Mn4+ doping into K2TiF6 host. By using as-prepared K2TiF6:Mn4+ phosphor as a red componet for warm W-LEDs, the high color rendering index (Ra = 84) and low color temperature (CCT = 3621 K) device performance proved that this environmental friendly synthesis method would be an efficient way to produce red fluoride phosphor for W-LEDs.

Experimental measurements were conducted to investigate the upward oil-water flow patterns in a small diameter vertical pipe (0.01 m I.D.) under high temperatures up to 130 °C and high pressures up to 20 MPa. The viscosity of the oil sample was 584.24 mPa s and the density was 1.899 g/cm3 at 30 °C. The effects of pressure, temperature, input water fraction (IWF) and mixture velocity on the flow patterns were systematically investigated. The observed flow patterns were plotted on a flow pattern map in which input water fraction was used as the y-axis and the mixture velocity was used as the x-axis. Based on the measurement results, the following flow patterns were observed: water-in-oil dispersed flow (D w/o), water-in-oil bubbly flow (B w/o), water-in-oil slug flow (S w/o), water-in-oil creep flow (CE w/o), churn flow (Churn) and core annual flow (AF). Phase inversion was not observed in this work. With an increase in temperature at a given input water fraction, S w/o, CE w/o and Churn flow with large water drops tended to transform into B w/o and D w/o with smaller water drops, the CE w/o disappears gradually, and the boundaries in the flow pattern maps tend to occur at lower input water fraction values. The effect of pressure on the flow patterns was found to be opposite to that of temperature. The possible causes leading to the changes in the flow patterns subjected to pressure/temperature variations were provided in terms of changes in density ratio, interfacial tension, and viscosity ratio of oil and water.

In recent years, current-carrying faults caused by overheating of GIS conductors have frequently occurred, posing a serious threat to the safe and stable operation of the power grid. When the GIS conductor has overheating defects, a local overheating area will be formed on the shell surface through the heat transfer of SF 6 . The overheating defects can effectively be found using the infrared thermometer to detect the temperature of the shell surface. Firstly, 3-D multi-physics coupled model was established to analyze the electromagnetic field, temperature field and gas flow field of 252 kV three-phase sub-aspect bus in GIS. Then, the overheating temperature rise characteristics in GIS and the influence of load current and ambient temperature were analyzed. The results show that the temperature rise distribution of the conductor and the shell shows an exponential decline. Under the convective diffusion of SF 6 , the shell generates overheating characteristics directly above the overheating defect. The larger the current, the greater the heating power loss, the faster the SF 6 convection diffusion rate, and the higher the temperature rise in conductor and shell surface. Ambient temperature has little effect on the temperature rise characteristics of GIS. However, the temperature of the conductor and the shell decreases due to increased heat dissipation as the ambient temperature decreases. And the overheating defects is difficult to find because of the weakness of overheating characteristic spectrum. The research results of this paper are helpful for accurate analysis of the infrared temperature measurement results on site, and have important engineering application value.

Oil seal wear is the main cause of early failure in airframe rod end-bearing. In this study, the thermal-stress-wear coupled finite element model of oil seal, the coupled dynamic differential equations of airframe rod end-bearing and oil seal were established. The influences of bearing dynamic characteristics and oil seal parameters on the oil seal wear characteristics were studied. The results are as follows: the evolution of the oil seal wear, the effects of the bearing dynamic characteristics and the oil seal parameters on the oil seal wear are developed. The oil seal parameters are optimized and the seal test shows that the average grease retention rate of the optimized oil seal increased by 17.3%.

DSA-type Ti/Ir x Sn 1-x O 2 electrodes were prepared by thermal decomposition method. The first-principles calculations were employed to study the effects of the doping element and its content to the main oxides on the relationship between the electronic structures and the photoelectrocatalytic(PEC) activity of Ti/Ir x Sn 1-x O 2 electrodes. The performance of the coatings was characterized using XRD, XPS, LSV and EIS. The results showed that: the band gap decreased with the increase of Ir content. An impurity level appeared in the forbidden band, which was conducive to the separation of photogenerated electrons and holes, improving the conductivity and photocatalytic activity of the electrodes. However, the excessive content of Ir would promote the recombination of electrons and holes and reduce the band gap. When the Ir content was above 25%, the forbidden band of the oxide coating could disappeare. The conductivity of the coating further improved, it sacrificed the photogenerated carriers and thus reduced photocatalytic activity of the electrode. Besides, reducing band gap would weaken the redox ability of photo generated electron-hole pair. Therefore, The PEC activity of the Ti/Ir x Sn 1-x O 2 electrodes was mainly depened on the effects of Ir content on the electronic structures of the Ir x Sn 1-x O 2 coatings. In our experiments, the Ti/Ir 0.0625 Sn 0.9375 O 2 electrode exhibited better PEC properties.

In order to further improve the precision forming efficiency of a sand mold digital patternless casting and reduce the amount of sand mold cutting, a method for near-net forming of the sand mold with digital flexible extrusion technology was put forward. The theory, optimization algorithm and technology for sand mold near-net forming were studied. Experimental results show that the sand mold forming efficiency can be increased by 34%, and the molding sand can be reduced by 44%. The method for near-net forming of a sand mold with digital flexible extrusion technology can effectively promote the application of digital patternless casting technology in the mass production of castings and thus greatly improves the efficiency and automation of sand mold manufacturing.

Advanced reduced graphene oxide/ZnS (RGO/ZnS) hybrids were synthesized via a facile and effective hydrothermal method to enhance the tribological properties of epoxy coatings. Physical characterization of the hybrids indicated that the as-prepared products had the high chemical purity and that the ZnS nanoparticles combined well with RGO nanosheets. Meanwhile, ZnS nanoparticles were uniformly dispersed on RGO nanosheets with the diameters of several decade nanometers. The tribological properties of ZnS, RGO, and RGO/ZnS with epoxy coating were systematically investigated. By comparing the result of tribological study, it was found that RGO/ZnS hybrids had better lubricating properties with lower coefficient of friction and higher wear resistance than those of ZnS or RGO. In addition, the test results indicated that RGO/ZnS hybrids showed good stability with increased in applied load. These excellent tribological properties of RGO/ZnS hybrids were attributed to the excellent synergistic effects between ZnS nanoparticles and RGO nanosheets and to the transfer film that formed on the steel ball. This work paved a way to expand the potential applications of nanoparticles in the tribological field.

This article takes the reducer with the involute helical gear as the research object, the diagnostic method of the broken tooth fault and the deterioration trend is researched by vibration spectrum graph, demodulation waveform graph, time domain waveform graph, demodulation spectrum graph. The research results show that vibration spectrum graph has the worst guidance for the broken tooth fault of the involute helical gear reducer, demodulation waveform graph has the poor guidance in the initial stage of the broken tooth fault, with the deepening of the severity of the fault, the fault characteristics of the waveform gradually become obvious, time domain waveform graph and demodulation spectrum graph are the effective means to discover the initial fault and monitor the fault changes.

A mechanochemical reactor providing strong shear-force has been developed in order to graft the polar groups onto the polymers. The extent of polymers' chain scission is a key factor in grafting process. In order to evaluate the scission extent, the shearing experiments were carried out for GPPS152P, which were produced by SECCO Petrochemical Company, Shanghai, China, at different revolving speeds, and temperatures. The decrease in molecular weight of GPPS152P was evaluated through gel permeation chromatography method and was estimated to be 13.8%. Additionally, the molecular weight distribution (MWD) of this sample became narrower. The chain scission theory and the shear rate, simulated through POLYFLOW software, were simultaneously employed to conduct quantitative analysis of molten PS' chain scission process. According to this method, the decrease in molecular weight was estimated to be 12.88%. Therefore, this method can be taken as a guideline for estimating molecular weight and MWD of products in manufacturing industry. POLYM. ENG. SCI., 2017. © 2017 Society of Plastics Engineers

DSA-type Ti/RuxSn1-xO2 electrodes were prepared by thermal decomposition method as photoelectrocatalysts (PECs) and extensively characterized by various sophisticated techniques. First-principles calculations was employed to study the effects of Ru content on the electronic structures of the RuxSn1-xO2 coatings. The photoelectric-synergistic catalytic activity of the Ti/RuxSn1-xO2 electrodes was evaluated for the degradation of methyl orange (MO) in aqueous solution. The results show that the RuO2-SnO2 solid solution could be formed. The band gaps of the RuxSn1-xO2 coatings gradually decreased and eventually turned into metallic conductivity with the increase of ruthenium content. As a PEC electrode, reducing band gap is helpful to improve electronic conductivity and the electrocatalytic activity, but not always advantageous to increase the photocatalytic activity. Because too narrow band gap will sacrifice the photogenerated charge carriers and thus reduce photocatalytic activity of the electrode. In our experiments, the rate constant of Ti/Ru0.05Sn0.95O2 electrode increased with increasing Ru content and exhibited the maximum rate for 5% Ru loading. The stability test showed the photoelectrocatalytic activity of the Ti/Ru0.05Sn0.95O2 electrode almost had no attenuation after 100h photoelectrolysis, revealing that this electrode has good long-term stability.

A much simpler and broadly applicable dip-coating method using silica nanoparticles and a silane coupler for preparing hydrophobic paper is presented. Both producing surface hydrophobization without additional surface treatment and increasing the adhesive force between the paper and the coated material can be realized by an almost one-step procedure. The modified filter paper could not only selectively permeate oil from a mixture, but also exhibits superior recyclability, indicating its great potential application in the oil–water separation area.

A novel ternary-alkaline red emitting fluoride phosphor K2NaGaF6:Mn4+ was successfully synthesized through co-precipitation method. The crystal structure, morphology, electronic band structure and luminescence properties of K2NaGaF6:Mn4+ phosphors were investigated in details by using Rietveld refinement of X-ray diffraction data, scanning electron microscopy (SEM), density functional theory (DFT) calculation and different reaction parameters. The K2NaGaF6 host has a cubic unit cell with the space group Fmm and lattice parameters of a = 8.2577 (4) A, Z = 4, Vcell = 563.08 (8) A3. Under blue light excitation, Mn4+ activated K2NaGaF6 exhibits a bright narrow-band red emission. The PL properties of the K2NaGaF6:Mn4+ red phosphors were optimized with different Mn4+ concentrations and aging times. A warm-white LED device was fabricated using a blue LED chip combined with commercial yellow YAG:Ce3+ phosphor and synthesized K2NaGaF6:Mn4+ red phosphor. The color rendering index (CRI, Ra = 81.6) and corresponding color temperature (CCT = 3643 K) easily reached the commercial warm white light LED standards (Ra > 80 and CCT < 4000 K). All these results indicate that K2NaGaF6:Mn4+ phosphor would be a suitable red phosphor candidate for warm-white LED applications.

As a potentially attractive candidate of LTCC material, Bi1.5Zn1.0Nb1.5O7 ceramics with substituted Zn2+ were synthesized by a conventional mixed oxide route. For the first time, the effect of the chemical ionic substitution of Sr, Ca and Mn cations on the microstructure, bond energy and dielectric properties of bismuth-based pyrochlores was discussed systematically for Bi1.5Zn1.0Nb1.5O7. Rietveld refinement was carried to analyze the structure variation of the sintered specimens. The solid solubility limits of in the Bi1.5Zn1.0Nb1.5O7 system with Sr, Ca and Mn incorportion were discussed. The samples presented single cubic phase that were used to study the dielectric properties of Bi1.5Zn1.0Nb1.5O7 based on the crystallization and microstructure. The dielectric constant er was mainly related to relative density not the ionic polarizability. The relative density and the dielectric constant er showed the same decreased trend as a function of different ionic dopant. And the change of the grain size and grain boundaries had a significant influence on the loss tangent tanδ in this system. The A-site cation bond energy of (Bi1.5Zn0.4M0.1)(Nb1.5Zn0.5)O7 (M = Sr, Ca, Mn, Zn) ceramics was performed to explain the relationship between the temperature coefficient of the dielectric constant τe and the crystal microstructure in a new way. With the decrease of |τe| values as a function of the substitution, the Zn–O bond energy of A-site became strong. This indicated that the (Bi1.5Zn0.4M0.1)(Nb1.5Zn0.5)O7 system tended to be stable.

Induction cooker i.e. IC, has huge market for high efficiency, reduced heating time and safety. IC technology develops towards higher induction efficiency and compatible to vessels with different material. These require an equivalent impedance model of IC, which is suitable for varying winding turns, frequency and vessel material. There were several impedance models of IC based on transformer model, however, without computational impedance characteristic. Hence, this paper proposed an impedance model based on mutual inductance. By analysis of eddy current field, the mutual inductance and equivalent impedance are derived. Based on that, the induction efficiency is analyzed, and effectively improved with optimal higher frequency and winding turns. Prototype with varying frequency, winding turns and material of vessel is built up, verifying the accuracy of this proposed impedance model. Furthermore, the induction efficiency is improved by 2.12% for GB45 vessel, and by 20.76% for Al vessel.

Sleeve-base structure interference fits are widely applied as a prominent role in mechanical products. The sleeve parts are very vulnerable, so they are disassembled and repaired frequently. Unfortunately, the existing disassembly methods have great damage to those parts. How to achieve nondestructive disassembly for those components is a difficult problem in the field of remanufacturing. This research puts forward a dismantling method of interference fit of sleeve-base structure in the case of cooling excitation. Using liquid nitrogen to cool the contained part, cooling deformation is occurred and the interference fit is weakened, so that nondestructive disassembly is implemented. Taking the sleeve-base model as research objects, the transient heat transfer differential equations under liquid nitrogen cooling excitation are established, and transient temperature field is solved by Laplace transformation and numerical inversion; based on thermoelasticity, disassembly force equation is derived, and theoretical model of cooling excitation disassembly method is developed. A finite element simulation is done with the brass sleeve and 45# steel base model, and a comparison between it and the theoretical analysis is carried out. The results show that: (1) The simulation result of the temperature field has a good inosculation with the calculation of analytical model, and the error of disassembly force between finite element model and theoretical model is only 3.9%. (2) The curves function with disassembly force and cooling time of different interference connection models is obtained by the simulation analysis, which shows that interference fit is obviously weakened and the disassemble force is greatly reduced.

Uniaxial compressive stress-strain curves of several groups of basalt fiber crumb rubber mortars (BF-CRM) with different contents are tested. By comparing with the GZH model, the improved values of the parameters of the BF-CRM constitutive model based on the GZH model are obtained. Then, taking the supporting scheme of main substation of the mine as the background, using FLAC3D to simulate the roadway support, using BF-CRM to replace the ordinary mortars in the original support, and combining with the triaxial compression test of different confining pressure, the application effect of BF-CRM in roadways support is studied and analyzed.

The large aperture deuterated potassium dihydrogen phosphate (DKDP) is an important frequency conversion crystal in a large power laser device. There are many defects inside the DKDP bulk material, including the varying element impurities and electronic defects. Comparing with the defect-free material, these bulk defects can easily absorb incident laser energy and pose the risks of initiating damage sites when exposed to high-energy lasers. Beside bulk defects, there are surface defects originating from the DKDP machining process, including cracks, scratches and protuberances. These surface defects affect the damage performance of DKDP crystal by increasing light absorption and weakening local mechanical strength. Due to the defects from both bulk and surface, the actual damage threshold of DKDP crystal is much lower than the expected theoretical value. The lack of its laser damage resistance seriously restricts the laser output power. In this study, the off-line sub-nanosecond laser conditioning technology is proposed to effectively improve the laser damage performance of large aperture DKDP crystal. Its principle is to irradiate DKDP with a mild laser fluence in advance. Although the laser pretreatment cannot directly eliminate the impurities, dislocations, grain boundaries or other macro structural defects in crystals, it indeed changes the distribution and density of intrinsic point defects on a micro-scale. It suggests that the complicated reactions of electron-hole, atom-vacancy and the intrinsic point defect annihilation caused by the microstructural transformation of crystal materials under laser conditioning are the possible reasons for reducing absorption and improving the damage resistance. In this experiment, the result of the damage to high-power laser device shows that the mean surface damage density of DKDP crystal at 9 J/cm2 decreases from 5.02 pp/cm2 to 0.55 pp/cm2 after sub-nanosecond laser conditioning. The laser conditioning can remove the protuberance defects on the surface, thus reducing the surface damage density. In addition, the damage size probably decreases after laser conditioning. There is a leftward shift in the damage size curve after laser conditioning, and its peak decreases from 25 μm to 18 μm–20 μm. In addition, due to the removal effect of laser conditioning on defects, the spatial distribution of damage points after sub-nanosecond laser irradiation turns more uniform. This study provides a foundation for the applications of off-line sub-nanosecond laser conditioning technology in high-power laser facility.

A series of efficient red phosphors, K2SiF6:Mn4+ (KSFM) particles with highly regular, uniform and anisotropic shapes, were successfully prepared by a two-step chemical co-precipitation method at room temperature without using surfactant and template. A morphological map for KSFM particles with five distinctive shapes was depicted by adjusting KF-HF precipitator dropping speed. Moreover, the photoluminescence, decay curves and Raman spectral dependence of the KSFM phosphors with different morphologies were investigated. Luminescence intensity of the KSFM phosphors is highly correlated with the morphology of KSFM particles, which gradually increased as the particle shapes changed from cube to octahedron. Whereas, Raman spectra and flame atomic absorption spectrophotometer results indicated that Mn4+ concentration in a series of KSFM particles decreased gradually. Growth mechanism of particle is discussed base on reticular density and surface energy. White LED devices made of a blue GaN chip merged with yellow phosphor (YAG: Ce3+) and the obtained KSFM red phosphor could produce warm white light. Drive current testing of the fabricated w-LEDs proved the KSFM phosphor in octahedron shape is more stable than that of the KSFM in cubic shape.

As a promising candidate for thermostable Low-temperature co-fired ceramic material with NP0 characteristic, (Bi1.8Zn0.2)(Zn0.6Nb1.4−2xSn x W x )O7 (x = 0.00, 0.02, 0.05, 0.10) dielectric ceramics with improved dielectric properties were prepared by conventional mixed oxide route. The effect of the chemical substitution of Sn4+ and W6+ cations on the structure and dielectric properties in this system had been investigated systematically. The Sn4+ and W6+ co-substitution was tentatively introduced in cubic-monoclinic pyrochlores co-existing ceramics and the results showed regular influence on the structure, dielectric properties with the amount of substitution. With the structure evaluation and electrical properties measurement results, the Sn4+ and W6+ substituted Nb5+ in B site showed an effective way to depress the grain growth and the ceramic with fine grains in 1–3 μm that can be obtained at a low sintering temperature of 950 °C. Based on these results, small amount of Sn4+ and W6+ substitution was successfully applied to a base ceramic with the electrical properties, which can be a promising candidate for LTCC and multilayer components applications in high frequency and microwave range.

We have performed unbiased searches for the global minimum structures of (FeS) n + (n=1–5) clusters using the CALYPSO method combined with density functional theory geometric optimisation. A large number of low-lying isomers are optimised at the B3PW91/6-311+G* theory level. Accurate ab initio calculations and harmonic vibrational analyses are undertaken to ensure that the optimised geometries are true minimum. They show that the most stable structures begin to exhibit three-dimensional (3D) configurations at n=3. The relative stabilities of (FeS) n + clusters for the ground-state structures are analysed on the basis of binding energies and HOMO-LUMO gaps. The theoretical results indicate that the binding energies of (FeS) n + tend to increase with cluster size. The maxima of HOMO-LUMO gaps (3.88 eV) for the most stable configurations appear at (FeS)+. Moreover, we have found that the (FeS)2 + cluster possesses the lowest local magnetic moments compared to the other species. The origin of this magnetic phenomenon is also analysed in detail.

A single-layer frequency selective surface (FSS) with wide stop band is proposed and applied in reducing the radar cross section (RCS) of the spiral antenna in this article. The element of the FSS consists of toothed spindle-shaped cross and rings. With the spindle-shaped cross and the toothed edges, the operating band of the FSS is enhanced and extended to the high frequency range. The metal rings are laid between the arms to decrease the coupling. The results show that the stop band of the FSS is 3.4–5.8 GHz under the condition of |S21

The phenomena and mechanism of electrospray modes in nanoscale are investigated from experiments and molecular dynamics simulations. It is found that the ionic concentration plays a crucial role in determining the dripping or the jetting modes in a nanoscale electrospray system. Molecular dynamics simulations uncover that the two modes are caused by the competition between the electric field stress and surface tension, which is similar to the mechanism in a macroscale electrospray system. However, in a nanoscale electrospray system, the two competing forces of the electric field stress and surface tension are more sensitive to the ion distributions than that in a macroscale electrospray system, in which the applied voltage and pressure dominate. With the decrease of the nozzle diameter to nanoscale, the ions not only affect the local electric field stress, but also destroy the hydrogen bonds among water molecules, which lead to that the ion concentration becomes a dominant factor in determining the electrospray modes in nanoscale. The discovery provides a novel method to control nanoscale electrospray modes, which may find potential applications for mass spectrometry, film deposition, and electrohydrodynamic printing.

Interstitial free (IF) steel disks were subjected to various degrees of revolution during application of the high-pressure torsion (HPT) process, and the resulting distributions of hardness and microstructure during the early torsion stage of high-pressure torsion (HPT) were investigated using experimental and simulation approaches. The results indicated that the deformation in the HPT-processed IF steel disk was inhomogeneous, producing low hardness in the center and high hardness in the edge region. The experimental results, including the hardness and microstructure distributions, indicated that the severe deformation zone proceeds gradually from the center to the edge of the HPT disks in the early torsion stage, and also confirmed verify that the deformation on the upper surface of the disks lags behind that on the bottom surface. Simulation results from a finite element method analysis strongly supported the experimental conclusions. (Received December 30, 2016; Accepted July 2, 2017)