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Reliable transient thermal analysis plays a very important role in the engine safety analysis. Transient conjugate heat transfer simulation is an important way of temperature analysis. But there exists a great disparity in the time scales between solid conduction and fluid convection. The calculation cost of transient conjugate heat transfer analysis is very huge because of the tiny time step of computational fluid dynamics. The Bi-Fo time scaling method is proposed to improve the computational efficiency of transient conjugate heat transfer. On the one hand, this method carries out a similar transformation on solid heat conduction, scaling the calculation time with the product of density and specific heat capacity to maintain the consistency of Fourier number. On the other hand, it takes very short time for the fluid domain to recover stability after a boundary disturbance. Based on the above characteristic, the flow time is directly compressed to the same as that of the solid domain. It is verified by Mark Ⅱ vane that increasing the solid thermal diffusivity can reduce the time scale of heat conduction. In the situation of rapidly stable flow field, scaling flow time does not affect the solid thermal boundary under corresponding dimensionless time. Within the application scope, the Bi-Fo time scaling method can greatly reduce the time cost of transient conjugate heat transfer simulation while maintaining the accuracy of transient temperature analysis.

Photocatalytic degradation of pollutants has attracted much attention because it can effectively solve the problem of environmental pollution. SiO2@Eu(TTA)3phen@TiO2 core-shell structures were successfully synthesized for the first time by a solvothermal method involving ultrasound assistance which can optimize the rare earth complex dispersibility and achieve strong emission intensity. SiO2@Eu3+@TiO2 core-shell structures were also successfully synthesized by a similar method. Photocatalytic activity analysis showed that the photocatalytic activity factor not only depended on the rare earth ion content, but also related to the structure and size of the TiO2 nanoparticles. Photocatalytic activity increased first and then decreased with the quantity of rare earth ions. Photocatalytic activity was also superior for hollow structures compared to solid structure. Photocatalytic activity of SiO2@TiO2 particles increased with the particle size, until the size increased to 450 nm. Rare earth ions content as well as particle structures and sizes affected efficiency for the photocatalytic degradation of methyl orange. Outstanding photocatalytic activity provides the composite particles with improved potential to purify aquatic contaminants and to meet the demands of future environmental remediation applications.

The Li7La3Zr2O12-based garnet (LLZO-BG) electrolyte has the advantage of strong thermal stability and can, therefore, avoid the flammability problem of organic electrolyte solutions. However, the solid-state lithium battery with LLZO-BG electrolyte has a much larger electrochemical resistance and poorer performance than the battery with an organic electrolyte solution, which is mainly related to the electrolyte/electrode interface. From the perspective of the LLZO-BG/Li interface, this review explores several interrelated interfacial issues, including the air instability of LLZO-BG, poor LLZO-BG/Li interfacial contact, easily generated lithium dendrite and the instability of LLZO-BG with the Li anode. We elaborate on the forming mechanisms, affecting factors and measures for improving these issues, and prospects for the future research directions of the LLZO-BG/Li interface. This review can provide new ideas for producing a solid-state lithium battery with high safety and high energy density.

Succinonitrile (SN)-based electrolytes are attractive due to their considerable ionic conductivity and high oxidative stability. However, the spontaneous chemical side-reactions between SN and Li-metal restrict the extensive applications of such electrolytes in next-generation advanced Li-metal batteries. Herein, we report a novel SN-based electrolyte SN–DLi–FEC which combines the dual-salt (lithium bis(trifluoromethane sulfonimide) (LiTFSI) and lithium difluoro(oxalato)borate (LiODFB)) and the fluoroethylene carbonate (FEC) additive. Compared with other SN-based electrolytes such as SN–SLi–FEC (single salt combined with FEC), SN–DLi–FEC can form a more stable and durable organic–inorganic composite SEI film rich in the B–F bond and LiF on the surface of the Li-metal anode. As a result, interfacial compatibility of the SN-based electrolytes and the Li-metal anode can be significantly enhanced. Moreover, SN–DLi–FEC shows high oxidation resistance, high ionic conductivity and good thermal stability. The LiCoO2 (LCO)/Li battery equipped with SN–DLi–FEC exhibits excellent electrochemical performances at room temperature (RT) and high temperature, and high thermal safety. The novel SN-based electrolyte prepared in this work could be a promising candidate providing better reliability and safety for the development of Li-metal batteries.

To design thermal fit parameters such as heating temperature and insertion force, it is generally necessary to conduct structural and thermal analyses, respectively. This study aims to build an int...

Dynamic surfaces play a critical role in templating highly ordered complex structures in living systems but are rarely employed for directing assembly of synthetic functional materials. We design ion gel templates with widely tunable dynamics ( Tg) to template solution-coated conjugated polymers. We hypothesize that the ion gel expedites polymer nucleation by reconfiguring its surface to facilitate cooperative multivalent interactions with the conjugated polymer, validated using both experimental and computational approaches. Varying ion gel dynamics enables large modulation of alignment, molecular orientation, and crystallinity in templated polymer thin films. At the optimal conditions, ion-gel-templated films exhibit 55 times higher dichroic ratio (grazing incidence X-ray diffraction) and 49% increase in the relative degree of crystallinity compared to those templated by the neat polymer matrix. As a result, the maximum hole mobilities increase by factors of 4 and 11 along the π-π stacking and the backbone directions. Intriguingly, we observe a synergistic effect between the gel matrix and the ionic liquid that produces markedly enhanced templating effect than either component alone. Molecular dynamics simulations suggest that complementary multivalent interactions facilitated by template reconfigurability underlie the observed synergy. We further demonstrate field-effect transistors both templated and gated by ion gels with average mobility exceeding 7 cm2 V-1 s-1.

In this article, we start with the spatial dispersion difficulty encountered in the solution of physical phenomena controlled by partial differential equations. The one-dimensional diffusio...

Traditional methods fail to predict the pumping pressure loss of high-performance concrete properly in super high-rise pumping situations due to complex changes of concrete properties. Therefore, it is imperative to propose a relative accurate method for pumping pressure estimation in super high-rise buildings. This paper builds the simplified pressure calculation method “pressure induced by the gravity plus pressure along the pipe line.” The later one is gained by establishing topology optimized model based on computational fluid dynamics and considering the lubrication layer formation. The effect of rheological properties and flow rate is analyzed based on this model in detail. Furthermore, the developed calculation method is verified by the measured pumping pressure during the super high-rise building construction of the Shanghai Tower (the tallest building in China recently). The relative differences between the calculation results and the measured data in situ are less than 6%, indicating the applicability of this method for predicting the pressure loss of the super high-rise pumping.

Lithium (Li) metal has been proposed as the most promising anode for secondary lithium batteries with high energy density due to its considerable theoretical capacity (3860 mAh g−1) and lowest electrochemical potential (-3.04 V vs standard hydrogen electrode). However, the uncontrollable dendrite Li issues over repeated plating/stripping process results in huge volume change, low Coulombic efficiencies (CEs), and poor cycling performance. Here, a solid electrolyte interphase (SEI) layer mainly consisting of biphasic hybrid Li3Sb and LiF has been successfully in situ constructed on Li surface by spontaneous chemical reaction between Li and SbF3. The modified SEI can induce Li ions depositing on the linked-particle layer resulting from the relative low lithium diffusion coefficient of SEI layer component. The Li/Li symmetric cells with SbF3-modified Li (SF-Li) anodes show stable cycling over 400 h at 3.0 mA cm−2 for 3.0 mAh cm−2. The Li-S batteries with SF-Li anodes and ether-based electrolyte can achieve steady long-term cycling performance and high CEs. Particularly, the high voltage LiCoO2 (LCO)/Li batteries with SF-Li anodes and carbonate-based electrolyte also deliver excellent electrochemical properties even at harsh conditions. This work offers a new strategy to regulate Li ion deposition and benefits for the further development of safe Li metal batteries (LMBs).

Recently, rechargeable lithium metal polymer battery (LMPB) attracts increasing attention because of its high safety and energy density properties. However, the high contact interfacial resistance of solid-state electrode and electrolyte is still an obstacle to satisfy the demand of high current density and long cycle stability, especially at room and lower temperature. Here, we develop a simple and efficient heat treatment method, to improve the interfacial compatibility between electrode and electrolyte in all-solid-state LMPB, successfully realizing workable LMPB at a reduced temperature (30 °C). The LMPB shows excellent cycling performance and rate capability in the voltage range of 2.5–4.2 V. The behavior of Li+ plating/stripping on the surface of lithium metal anode is greatly enhanced. Meanwhile, the interfacial resistance of the LMPB decrease significantly after the heat treatment process.

Satisfactory electrochemical stability of extrinsic-interfaces between electrodes and electrolyte is the prerequisite for the safe and durable applications of all-solid-state Lithium batteries (ALBs). Unfortunately, the oxidative decomposition of anions from Li-salt at the extrinsic-interfaces of cathode side leads to the electrochemical instability during charge process. Here, a novel composite polymer electrolyte (CPE) containing flyash-treated (FA) submicro/micron particles and poly(ethylene oxide) (PEO) matrix is reported. After the addition of FA filler, Li+ transference number increases from 0.21 to 0.37 and electrochemical stability window reaches 5.2 V. FA as filler can efficiently immobilize (trifluoromethanesulfonyl) imide (TFSI–) anions and mitigate their irreversible oxidative decomposition at the extrinsic-interface of cathode||CPE due to the internal binding interaction between TFSI– anions and FA particles. ALBs using CPE with FA can not only provide stable extrinsic-interfaces for uniform Li deposition, but also tolerate strong electrochemical polarization with excellent cycling performance.

Lipase was immobilized with Cu3(PO4)2⋅3H2O to synthesize lipase-Cu3(PO4)2⋅3H2O hybrid microflowers (Lip-MFs). Surfactants (Tween 80, Triton X-100 and CTAB) were added to study their effect on the morphology and activity of Lip-MFs. SEM images revealed that surfactants can increase the size of Lip-MFs and make the hierarchical structure more compact. Further, compared with other surfactants, the activity of CTAB-Lip-MFs was 1.45 times of that of free lipase, demonstrating CTAB is conducive to improve the activity of lipase.

As one of the most promising next generation energy storage systems, lithium sulfur (Li-S) batteries with high specific energy density have received extensive attention due to the advantages of resource abundance, low toxicity and super high specific energy density (>2500 Wh kg−1). However, the unfavorable shuttle effect caused by dissolved polysulfides during charging/discharging processes results in low Coulombic efficiency (CE), poor interfacial stability, uncontrolled lithium dendrite growth and rapid capacity degradation, hindering the practical application of Li-S batteries. Herein, a highly stable armor-like artificial solid electrolyte interphase (SEI) layer for Li metal anode was formed based on the spontaneous interaction between Li metal and 4-chlorophenylboronic acid (CPB). First, this artificial SEI layer can avoid the direct contact between Li anode and electrolyte, therefore eliminating the corrosion reaction between Li metal anode and polysulfides in electrolyte. Second, the artificial SEI layer with high durability can effectively suppress lithium dendrite growth and stabilize Li anode/electrolyte interface. As consequence, the Li/Li symmetric cells show the lengthened cycling life over 500 h with steady and low polarization voltage under the condition of 1.0 mA cm−2 for 1.0 mAh cm−2. Furthermore, the Li-S cells with modified Li metal anode deliver superior cycling performance and higher CE at various sulfur loadings and rate conditions than those of the cells with pristine Li. This work highlights the key role of artificial SEI layer on stabilizing the Li anode, providing a new pathway for Li metal protection in Li-S batteries development.

Alkaline pectinase was one of the most effective enzymes to treat cotton as alternative agent to replace the conventional alkaline method. Removal of pectin and cutin was considered the explanation for improvement of wettability as well as water adsorption on cotton fiber. However, degradation kinetics of pectin is unclear, and the influence of fiber shape on property changes after enzymatic treatment was ignored. The main objective of this work was to reveal interactions between pectinase and cotton fiber for mechanism study. A heterogeneous catalysis kinetic equation, which is associated with Langmuir adsorption model and enzyme deactivation, was used to describe the heterogeneous catalysis. The enzymatic process conditions were optimized. Raw cotton fibers, pectinase-treated and alkali-treated fibers were characterized by impurities content determination, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). Mechanism of water adsorption enhancement on treated fibers was discussed. In addition to elimination of the outer impurities, flat fibers with less twist and shape changes of lumen were also obtained to ensure better accessibility and water adsorption after enzymatic treatment.

Due to poor operational stability and hard recovery of enzymes in industrial applications, enzyme immobilization techniques have gained considerable development. However, there are still big obstacles to apply immobilized enzymes for practical applications. Recently, a novel hybrid nanomaterial, i.e., enzyme-inorganic hybrid nanoflowers (HNFs), has presented a series of superior performances. Herein, the classification, synthesis, functionalization and potential applications of enzyme-inorganic HNFs are reviewed. First, an optimized classification of enzyme-inorganic HNFs is proposed. Enzyme-inorganic HNFs are first categorized into single-enzyme and multi-enzyme HNFs, which are subdivided based on metal phosphates and application fields, respectively. Second, synthesis conditions are discussed to optimize the fabrication of enzyme-inorganic HNFs. Third, the highlight part of this review is that supported, magnetic, chemically modified and antibody-modified enzyme-inorganic HNFs are summarized to better recycle enzyme-inorganic HNFs and satisfy the requirements of specific applications. Fourth, the latest applications of enzyme-inorganic HNFs are concluded including biosensors, biocatalysis, dye decolorization, protein digestion, enzyme purification, biofuel cell, beer brewing and detergent industry. Last but not least, current problems and prospects are proposed to suggest further study of enzyme-inorganic HNFs.

Solid-state electrolytes with high room temperature ionic conductivity, broad electrochemical window, and favorable thermal stability are crucial for the practical application of all-solid-state lithium-metal batteries. Here, a novel succinonitrile (SN)-based composite solid-state electrolyte (SN-CSSE) is fabricated directly inside the glass-fiber (GF) membrane via in-situ thermal-crosslinking ethoxylate trimethylolpropane triacrylate (ETPTA) monomer, coupled with the liquid SN-based electrolyte. The ionic conductivity, oxidation potential and lithium-ion transference number (TLi+) of SN-CSSE are 0.78 mS/cm, 5.20 V (vs. Li/Li+) and 0.68 at ambient temperature, respectively. The coin full cells equipped with high-voltage LiCoO2 (LCO) and modified Li metal anode deliver excellent interfacial stability, cycling reversibility, and rate capability. Moreover, the LCO/SN-CSSE/Li pouch cell exhibits more superior thermal stability than that of cell with commercial carbonate-based electrolyte during thermal shock test.

Grafting different kinds of nanomaterials on the surface of carbon fibers has been a feasible strategy for fabricating novel advanced materials. However, the bond strength between the nanomaterials and carbon fibers is a major challenge that limits the final properties of the materials. In this study, ZnO nanorods (NRs) were synthesized in an aqueous solution over ZnO films, which were deposited using a radio frequency magnetron sputtering technique. The experimental conditions for the magnetron sputtering process were designed based on an orthogonal test, and the ZnO islands exhibited different shapes and sizes under different deposition conditions. ZnO NRs, which were synthesized on all ZnO films, present the same hexagonal prism shape. In addition, TEM images show that ZnO NRs, ZnO films, and graphite structure of carbon fiber present a lattice matching that makes it possible to achieve an ultra-high bond strength of ZnO NRs. The results obtained for interfacial shear strength show that the bond strength of ZnO NRs is strongest when deposition time, substrate temperature, pressure ratio of Ar and O2, and power are 60 min, 200 °C, 0.15, and 200 W, respectively. We demonstrate that the higher crystallinity and uniformity of ZnO films result in a better bond strength of ZnO NRs.

Nanogenerators (NGs) based on the piezoelectric property of ZnO nanowires (NWs) have become an important component to harvest mechanical energy from the environment. In one category of ZnO NGs, the high-work function noble metal electrode is applied to deflect ZnO NWs, and electricity is generated due to the Schottky barrier formed between ZnO NWs and the noble metal. Herein, an insulating layer was used to replace the expensive noble metal to accumulate net charge, and a novel NG was composed by carbon fibers (CFs) and ZnO NWs. Because of a relative slip among CFs, ZnO NWs would generate inner potential by bending each other. Due to the combination of an enormous number of ZnO NWs, an electric output of 2 mV and 0.2 nA was generated. Current–voltage curves indicated the entire ohmic contact of the designed NG, while electrochemical impedance spectroscopy demonstrated the existence of an interface barrier. Since a noble metal electrode was avoided in the ZnO NG, the manufacturing cost was reduced and the fabrication process was simplified. This study proposes a novel strategy for designing feasible ZnO NG in extensive applications.

An unsophisticated preparation of silica@Eu spheres has been investigated. Many experimental tests, such as transmission electron microscopy and energy dispersive spectrometer mapping, were carried out to confirm that the rare earth complex coats the surface of silica spheres and also confirming the formation of silica@Eu. The combination of silica and a rare earth complex is realized by a simple binding force of nitrogen and fluorine in the ligand and the hydrogen bond on the surface of silica from an x-ray photoelectron spectroscopy test. The synthetic composite fluorescent microsphere greatly improves the thermal stability, as compared with a pure complex. The relationship between emission intensity and diameters of silica is also investigated. The results of the study found that as the size of silica increases, the fluorescence intensity enhances. Furthermore, the increase in size also extends the fluorescence lifetime to some extent. With the embedded structure, the europium complex has better dispersion and other properties, which means that it has broader application prospects, such as bioimaging, fluorescent markers, and optoelectronic devices.

Owing to high safety and considerable energy density, rechargeable all-solid-state lithium-metal polymer batteries (ASSLPBs) with organic-inorganic composite solid-state electrolytes (CSSEs) have been recognized as one of the most promising battery systems. However, 4 V or above-class ASSLPBs still suffer serious capacity degradation arising from the complex interface issues between the electrode and electrolyte. Herein, for the first time, we find the oxidation decomposition of TFSI- anion and further interaction with PEO polymer matrix in the LiNi0.8Co0.1Mn0.1LiO2 (NCM811)/CSSEs (PEO-LiTFSI-LAGP)/Li cell, which cause continuous damage to the interfacial stability and persistent capacity degradation. Increasing the ratio of LAGP filler in CSSEs membrane and employing PEO-LiBOB electrolyte in composite cathode were demonstrated effective. As a consequence, the ASSLPBs show high reversibility, and high capacity retention up to 88% (3.0–4.2 V) and 78% (3.0–4.3 V) after 100 cycles with the charge/discharge current density of 30 mA g−1 (35 °C). The understanding on capacity degradation mechanism, along with the positive improvement strategies validly boosts the development and promising application of 4 V-class ASSLPBs.

The internal air system, as one of the important subsystems of the aeroengine, is used to cooling and sealing, and plays a vital role in the safe operation of the engine. Especially in rapid transients, the complex dynamic response in air system may impose hazardous transition state loads on engine. Cavity is a component with pretty evident characteristics of transient in the air system due to the storage and release effects on the air. The flow and heat transfer characteristics of cavity should be made clear to precisely quantify the performance of the air system. The traditional study on cavity is based on the adiabatic assumption. However, the assumption is applicable to the transient of millisecond time scales physical phenomena in the air system, which is not usually common. Generally, the actual transition process is not instantaneous. Great discrepancies exist in the process of transition predicted by the adiabatic hypothesis compared with the practical process. The objective of this work is to propose a feasible method to solve the heat transfer issue throughout the transient process, which has not been settled by a proper method before, and develop a model for simulating the transient responses of the cavity with consideration of the heat transfer effect on the basis of the method. The model can predict transient responses under different thermal boundary conditions. Experiments have been developed for investigation of the charging process of the cavity. The thermal boundary can be controlled in the experiment, and the pressure and temperature responses of the cavity under different thermal boundary conditions have been analyzed. The non-dimensional numbers related to heat transfer characteristics were deduced by dimensional analysis, and the empirical formula of characteristics was proposed based on the experimental results. The non-adiabatic low-dimensional transient model of the cavity was established based on the heat transfer characteristics correlation. Results of transient responses calculated by non-adiabatic model were compared with the experimental data. It is found that both the transient responses of pressure and temperature agree well, with the maximum relative errors less than 2%. By comparison, the relative errors of pressure and temperature calculated by adiabatic model are about 8% and 12%, respectively. Meanwhile, the tendency of temperature response deviates from the actual process. Thus, the modeling method proposed is feasible and high-precision. The present work provides a technical method for establishing a low-dimensional model to describe the transient responses of the cavity with high accuracy, and supports the component-level modeling of the transient air system.

The Mg–Zn–Y–Zr alloys, which exhibit high strength and high elongation, have great potential for applications in many fields, such as automotive, aircraft, and aerospace industries. However, plastic deformation behavior under hot compression is still not fully understood. Hot compression tests of extruded Mg–Zn–Y–Zr alloy were performed at temperatures from 250 °C to 450 °C and strain rates from 0.001 s−1 to 1 s−1. A constitutive equation and processing map were developed to describe the flow characteristics. In addition, isothermal forging tests were conducted to verify the optimal deformation parameters. The results show that the strain rate and deformation temperature exert remarkable influences on the flow stress. The average activation energy and the stress exponent of deformation were determined as 137.400 kJ/mol and 3.707, respectively. The efficiency of power dissipation was high for all deformation conditions compared to the cast Mg–Zn–Y–Zr alloy, and the processing map exhibited four domains with high efficiency of power dissipation. The optimal deformation temperatures and strain rates for extruded Mg–Zn–Y–Zr alloy were 350–400 °C and 0.001–0.1 s−1, respectively. Components were prepared successfully according to the optimal deformation temperature and strain rate, which exhibited good surface quality and no deformation defect. The component after aging treatment exhibited an ultimate tensile strength of 396 MPa, a yield strength of 356 MPa and an elongation of 5.2%.

Solution processable semiconducting polymers have been under intense investigations due to their diverse applications from printed electronics to biomedical devices. However, controlling the macromolecular assembly across length scales during solution coating remains a key challenge, largely due to the disparity in timescales of polymer assembly and high-throughput printing/coating. Herein we propose the concept of dynamic templating to expedite polymer nucleation and the ensuing assembly process, inspired by biomineralization templates capable of surface reconfiguration. Molecular dynamic simulations reveal that surface reconfigurability is key to promoting template–polymer interactions, thereby lowering polymer nucleation barrier. Employing ionic-liquid-based dynamic template during meniscus-guided coating results in highly aligned, highly crystalline donor–acceptor polymer thin films over large area (>1 cm2) and promoted charge transport along both the polymer backbone and the π–π stacking direction in field-effect transistors. We further demonstrate that the charge transport anisotropy can be reversed by tuning the degree of polymer backbone alignment., Controlling macromolecular assembly across length scales during solution coating of semiconducting polymers is still a challenge. Here the authors show a biomineralization inspired dynamic templating method that expedites polymer nucleation and assembly which allows for surface reconfiguration.

The hot deformation characteristics of as-extruded Mg–Gd–Y–Zn–Zr alloy have been investigated by isothermal compression tests in the temperature range of 300–500 °C and strain rate range of 0.001–1 s −1 . Several modeling approaches, including flow stress–strain curves, a constitutive Arrhenius type equation model and processing map were used to characterize the deformation behavior of as-extruded Mg–Gd–Y–Zn–Zr alloy in this study. In addition, isothermal precision forging of the component with complex shape was carried out to evaluate the optimum parameters for hot working of the alloy at elevated temperatures. The results show that the deformation activation energy of the experimental alloy was estimated to be 240.477 kJ/mol, and the stress exponent was 3.899. The optimum parameters for hot working of the as-extruded Mg–Gd–Y–Zn–Zr alloy were deformation temperatures of 380–450 °C and strain rates of 0.003–0.02 s −1 . According to the determined hot deformation parameters, three components were successfully prepared, and its possessed excellent surface quality, the ultimate tensile strength, yield strength and elongation of the component were 378 MPa, 283 MPa and 11.5%, respectively.

The fatigue crack propagation behavior and corresponding AE characteristics of extruded AZ31 magnesium (Mg) alloy were investigated in this study. The effects of specimen orientation and loading frequency were considered. By combining the AE parameter and waveform analysis with the micro-structural and fractograph observations, the findings of the study showed that crack extension and twinning at the crack tip were two major AE source mechanisms during fatigue crack propagation in the Mg alloy. More twinning events were observed in the transverse direction (TD) specimens than in the extruded direction specimens, which contributed to more cyclic deformation irreversibility and cumulative fatigue damage, leading to worse fatigue performance and higher AE counts in the TD specimens. The results also indicated that increasing the loading frequency could slightly increase the fatigue life, and significantly decrease the AE counts in TD specimens due to the frequency or strain rate dependence of twinning activity. These results suggest that twinning plays an important role in the fatigue process in this Mg alloy, and that the AE technique is capable of detecting crack propagation and twinning events during fatigue.

In the present study, the ground-state properties of Ni3X intermetallic compounds were analyzed by means of the first-principles pseudo-potential method using the Cambridge serial total energy package code. The calculated lattice parameters of Ni3X intermetallic compounds are in good agreement with the experimental and other theoretical data. The single-crystal elastic constants were calculated; the hardness, ductile, and plasticity of materials were analyzed. The calculated enthalpies of formation showed that all of intermetallic compounds were thermodynamically stable; Debye temperature and heat capacity are calculated and discussed. Moreover, the chemical bonding in these intermetallic compounds was interpreted by calculating the density of states, electron density difference distribution, and Mulliken analysis; magnetism properties were briefly analyzed.

Calcite with laminate structure was successfully prepared by culturing Synechocystis sp. PCC6803 with different concentrations of calcium chloride (CaCl₂) in BG11 media. S. PCC6803 was examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), laser confocal scanning microscope (LCSM) and energy dispersive spectroscopy (EDS). The effects of Ca²⁺ concentrations and pH values on calcification were investigated and the micro morphs of the CaCO₃ crystals were observed by means of SEM. These results showed that CaCO₃ crystals could be more easily formed with increasing the concentration of CaCl₂ in S. PCC6803 culture solution. S. PCC6803 could largely bind calcium ions, most of which were present in extracellular polymeric substances and on the cell wall. Inside the cells there were a lot of circular areas rich in calcium ions without the crystallization of calcium. Some cells produced a thicker gelatinous sheath outside of the translucent organic thin layer. And the cells inside also produced major changes that the original chloroplasts were almost transformed into starch grains whose sizes were from 0.5 to 1 μm with relatively uniform in sizes. At the same time the cell sizes significantly reduced to only about 8-9 μm almost changing to half of its original diameters. The calcite crystals with a highly preferred orientation induced by S. PCC6803 were observed with X-ray diffraction (XRD). A critical implication was that S. PCC6803 could induce bio-calcification and then mediate the further growth of CaCO₃ crystals in the biological system.

A pseudo-three-layer electrostatic repulsive out-of-plane actuator is proposed. It combines the advantages of two-layer and three-layer repulsive actuators, i.e., fabrication requirements and fill factor. A theoretical model for the proposed actuator is developed and solved through the numerical calculation of Schwarz-Christoffel mapping. Theoretical and simulated results show that the pseudo-three-layer actuator offers higher performance than the two-layer and three-layer actuators with regard to the two most important characteristics of actuators, namely, driving force and theoretical stroke. Given that the pseudo-three-layer actuator structure is compatible with both the parallel-plate actuators and these two types of repulsive actuators, a 19-element two-layer repulsive actuated deformable mirror is operated in pseudo-three-layer electrical connection mode. Theoretical and experimental results demonstrate that the pseudo-three-layer mode produces a larger displacement of 0–4.5 μm for a dc driving voltage of 0–100 V, when compared with that in two-layer mode.

As-cast Mg–Zn–Y–Zr magnesium alloy is subjected to forward extrusion in different conditions. The results show that mechanical properties of Mg–Zn–Y–Zr alloy remarkably deteriorate when extrusion temperature increases from 400 °C to 450 °C because of grain coarsening. Significant improvement in mechanical properties of the alloy can be obtained with increasing extrusion ratio from 0 to 25. However, when the extrusion ratio increases from 25 to 100, the mechanical properties of the alloy almost remain the same. The retardation of recrystallisation in the alloy is dominated by the presence of Mg–Zn–Y particles. Solution treatment at 510 °C (T4) causes complete recrystallisation and decrease of mechanical properties. Aging at 160 °C (T5) causes increase in both strengths and ductility of extruded alloy. In isothermal backward extrusion, the as-cast Mg–Zn–Y–Zr alloy exhibits an excellent workability at temperatures from 250 °C to 400 °C with a extrusion rate of 10 mm/s. Temperatures higher than 400 °C are not suitable for forming of the alloy because of heavy oxidation.

Thixoforging requires feedstock having a non-dendritic, equiaxed microstructure, which in some cases can be obtained by the recrystallization and partial (RAP) melting route. Based on the RAP route, squeeze casting–solid extrusion followed by partial melting is proposed to obtain the semi-solid feedstock for thixoforging. After squeeze casting–solid extrusion, unrecrystallized grains were elongated along the extrusion direction. As the temperature rises into the semi-solid regime, there is a sudden increase in the appearance of spheroidal grains. The occurrence of recrystallized grains is closely associated with the location of the first liquid to form above the solidus. Grain coarsening in the semi-solid state can be described by classical LSW equation in Ostwald ripening. The coarsening rate does decrease with increasing solid fraction, f s , for f s less than approximately 0.70, and then increases again with further increasing f s . With prolonged holding time, the grains coarsen and mechanical properties of thixoforged components decrease. Moreover, the AZ91D-RE thixoforged from starting materials produced by squeeze casting–solid extrusion followed by reheating at 570 °C for 5 min have extremely fine and uniform microstructure. The tensile mechanical properties of squeeze casting–solid extrusion formed AZ91D-RE are better than those of AZ91D-RE thixoforged from starting materials produced by squeeze casting–solid extrusion followed by partial melting.

Thixoextrusion involves processing alloys with a spheroidal microstructure in the semi-solid state. Before thixoextrusion, repetitive upsetting-extrusion (RUE) is introduced into the strain induced metal activation (SIMA) process to predeform AZ80 magnesium alloy. Microstructure evolution of RUE formed AZ80 magnesium alloy during partial remelting is studied at temperatures for times. Tensile mechanical properties of thixoextruded components are determined and compared with those of AZ80 magnesium alloy thixoextruded from starting material produced by casting. The results show that with increasing number of RUE passes solid grain size decreases and the rate of liquation is improved. Prolonged holding time results in grain coarsening and the improvement of degree of spheroidization. The variation of the solid grains with holding time obeys the Lifshitz, Slyozov and Wagner law. Increasing the heating temperature is favorable for the formation of spheroidal solid grains. The tensile properties for AZ80 magnesium alloy thixoextruded from starting material produced by RUE are better than those of AZ80 magnesium alloy thixoextruded from starting material produced by casting.

An as-cast Mg–Al–Y–Zn alloy was successfully processed by equal channel angular extrusion (ECAE) in the temperature range of 225–400 °C, and the influences of processing temperature on the microstructure and mechanical properties were investigated. The use of back pressure during one-pass ECAE of Mg–Al–Y–Zn alloy was favorable for eliminating the undeformed area in the billet. At the processing temperature below 250 °C, the microstructures were characterized by unrecrystallised structure and the precipitated phase Mg 17 Al 12 was elongated along the extrusion direction. With increasing processing temperature to 350 °C, a large number of recrystallised grains were obtained. Increasing processing temperature promoted workability but led to decrease in the strength of Mg–Al–Y–Zn alloy. Then billets of as-cast Mg–Al–Y–Zn alloy were extruded at different numbers of ECAE passes. It was found that the microstructure was effectively refined by ECAE and mechanical properties were improved with numbers of ECAE passes increasing from one-pass to four passes. However, strengths decreased slightly after five passes though the grain size decreased considerably.

High quality InAlN/GaN heterostructures are successfully grown on the (0 0 0 1) sapphire substrate by pulsed metal organic chemical vapor deposition. The InAlN barrier layer with an indium composition of 17% is observed to be nearly lattice matched to GaN layer, and a smooth surface morphology can be obtained with root mean square roughness of 0.3 nm and without indium droplets and phase separation. The 50 mm InAlN/GaN heterostructure wafer exhibits a mobility of 1402 cm 2 /V s with a sheet carrier density of 2.01 � 10 13 cm � 2 ,a nd a low average sheet resistance of 234 O/cm 2 with a sheet resistance nonuniformity of 1.22%. Compared with the conventional continual growth method, PMOCVD reduces the growth temperature of the InAlN layer and the Al related prereaction in the gas phase, and consequently enhances the surface migration, and improves the crystallization quality. Furthermore, indium concentration of InAlN layer can be controlled by adjusting the pulse time ratio of TMIn to TMAl in a unit cycle, the growth temperature and pressure, as well as the InAlN layer thickness by the number of unit cycle repeats.

Cyclic closed-die forging (CCDF) was introduced into the strain induced melt activation (SIMA) route to replace conventional upset or extrusion. The microstructure evolution of CCDF formed AM60B magnesium alloy heated into the semi-solid state has been investigated. Tensile mechanical properties for AM60B magnesium alloy thixoformed from starting material produced by the SIMA route were determined. The results show that the SIMA route (four-pass CCDF and partial remelting) produced ideal, fine semi-solid microstructure, in which completely spheroidal primary solid grains had a little amount of entrapped liquid. With increasing the equivalent strain, the solid grain size decreased and the degree of spheroidization tended to be improved. Furthermore, the rate of liquation was also slightly increased. Increasing the reheating temperature was favorable for obtaining spheroidal semi-solid microstructure and decreasing the probability of coalescence among solid grains. However, prolonging holding time resulted in grain coarsening. The tensile mechanical properties of the thixoformed components were influenced by the amount of equivalent strain during CCDF. Good elongation to fracture (15%) was obtained for thixoformed AM60B magnesium alloy component, with a yield strength of 199.2 MPa and a tensile strength of 306.7 MPa.

A structured lens with a large numerical aperture for high diffraction efficiency is proposed. This structured lens is formed by varying high-refractive-index-dielectric (HRID) square holes in a metallic film. Compared with previous structured lenses formed by varying air square holes, the modulated wavefront at the exit pupil of the structured lens is smoother and the diffraction efficiency is greatly improved. A dielectric film was introduced as a buffer layer to reduce the energy loss at the interface caused by the great impedance mismatching between air and the high refractive index dielectric. A lens with an aperture of 100 µm and a focal length of 50 µm was designed; its diffraction efficiency has been raised from 22.8% to 47.2% by the finite difference and time domain (FDTD) algorithm. This structured lens has the advantages of not only light weight and high compactness, but also large numerical aperture, high diffraction efficiency, and good imaging quality.

The aim of this work is to study the microstructure and mechanical properties of an as-cast AZ91D+Y magnesium alloy processed via two different severe plastic deformation techniques, equal channel angular extrusion (ECAE) and multi-axial forging (MAF). The grains were significantly refined after only one pass for both ECAE and MAF processed billets. However, the homogeneity of the SPD-processed microstructure increased with increasing number of passes. Micro-hardness and tensile tests showed that billets processed by ECAE and MAF techniques followed a same behaviour. With the increase of the number of processing passes (accumulated strain), the values of micro-hardness, yield strength, ultimate tensile strength and elongation were observed to increase. Grain refinement caused by dynamic recrystallization was introduced to explain the effects of the number of processing passes (accumulated strain) on the microstructure and mechanical properties of AZ91D+Y magnesium alloys processed by ECAE and MAF techniques.

Under solid oxide fuel cells (SOFCs) operating atmosphere, volatile Cr species are generated over the chromia scale of chromia-forming alloy interconnects, poisoning the cathodes and causing the rapid degradation of the fuel cell performance. In this study, the influence of the cathode composition and A-site deficiency of Perovskite ABO3 cathodes on their tolerance to Cr poisoning was investigated in detail through the electrochemical polarization and electrochemical impedance spectroscopy (EIS) analysis. Results showed that 5 mol% La-site deficient cathodes, La0.75Sr0.2BO3−δ (B = Mn, Fe), presented a good performance in resistance to Cr poisoning and electrocatalytic activity to oxygen reduction reaction in the presence of alloy interconnects under a constant current density of 0.2 A cm−2 in oxygen at 1073 K. B-site atom of Perovskite ABO3 cathodes has a strong influence on the mechanism of Cr deposition and cathodes performance, while proper A-site deficiency can greatly improve the cathodes electrochemical performance and slow down Cr deposition.

A new route, near-liquidus forging plus partial remelting, has been developed for obtaining globular microstructures. Firstly, a material is formed by near-liquidus forging for obtaining a fine dendritic microstructure. Globular microstructure can be produced by reheating the material into the semi-solid temperature range for a period of time. In this paper, an AZ91D alloy with the addition of yttrium was prepared by near-liquidus forging. Microstructure evolution during partial remelting was studied at temperatures and for times. Tensile mechanical properties of thixoforged components were also determined. It is shown that the fine dendritic structure firstly evolves into a blocky structure during partial remelting. With prolonged holding time, the blocky structure disintegrates into polygonal solid particles. Prolonging time and increasing temperature promote a faster spheroidization. Good mechanical properties are obtained for the thixoforged AZ91D alloy with the addition of yttrium prepared by near-liquidus forging, with a yield strength of 160.9 MPa and a ultimate tensile strength of 301.7 MPa and a elongation to fracture of 9.734%.

Massive ferrous sulfate with excess sulfuric acid is produced in titanium dioxide industry each year, ending up stockpiled or in landfills as solid waste, which is hazardous to environment and in urgent demand to be recycled. In this study, waste ferrous sulfate was used as a second raw material to synthesize nano α-Fe2O3 red pigment powders with a bacteria-assisted oxidation process by Acidithiobacillus ferrooxidans. The synthesis route, mainly consisting of bio-oxidation, precipitation and calcination, was investigated by means of titration, thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray fluorescence (XRF) to obtain optimum conditions. Under the optimum conditions, nano α-Fe2O3 red pigment powders contained 98.24wt.% of Fe2O3 were successfully prepared, with a morphology of spheroidal and particle size ranged from 22nm to 86nm and averaged at 45nm. Moreover, the resulting product fulfilled ISO 1248-2006, the standards of iron oxide pigments.

Aiming at the problem of the resolution reduction in a miniaturized grating spectrometer, we presented a method to improve its spectral resolution by inserting a tunable Fabry-Perot filter into its optical path before the grating. The Fabry-Perot filter was designed to filter out a partial spectrogram and separate the original undistinguishable spectral lines so as to make their actual wavelengths can be detected. The different cavity length of the Fabry-Perot filter is corresponding to the different separated partial spectrogram. Combining all the separated partial spectrograms, an entire spectrogram with improved resolution can be achieved. Experimentally, the spectral resolution of a grating dispersive system was improved from 2 nm to 1.2nm in a broad spectral range by insetting a homemade tunable Fabry-Perot filter, which demonstrated the feasibility of this scheme. The tunable Fabry-Perot filter is fit for miniaturization by using MEMS technology and is able to work as an independent module. The method proposed provides a potential way to improve the spectral resolution without reducing the spectral range of the existing miniaturized grating spectrometers.

The structure aberrations of color separating grating (CSG), which is caused by the fabrication process, generate great modulations to the laser beam when CSG is used in the final optical system of a high power laser system. The beam modulations may lead to severe optical damages to CSG itself and the system. In this paper, a comprehensive fabrication error model for CSG is developed to study the beam modulation characteristics in the near field. Through theoretical calculations and simulations, the near field diffraction pattern of CSG is obtained, and the relationship between beam modulations and CSG structural aberrations is presented. The results show that beam modulations are mainly caused by the stair depth error and the slope error. This study provides a convenient way to estimate the possibility of optical damages induced by CSG.