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With the development of high energy density battery technology, layered transition metal oxide cathode materials, particularly Ni-rich layered cathodes of Li-ion batteries are urgently required due to its high energy density. However, Li/Ni intermixing inevitably occurs in Ni-rich cathode materials and affects the materials in terms of structure and performance. This review comprehensively summarizes the causes of Li/Ni intermixing and analyzes its inevitability due to ionic radius, Ni migration, magnetic interactions, and thermal stability. In addition, the effect of Li/Ni intermixing on materials is summarized, particularly its benefits, which have not yet been comprehensively examined. Finally, the methods for regulating Li/Ni intermixing that corresponds to its causes are presented in detail. This review can help researchers fully understand Li/Ni intermixing and propose solutions for the current shortcomings of Li/Ni intermixing research and directions for future studies.

Despite their high theoretical energy density, the application of lithium-sulfur batteries is seriously hindered by the polysulfide shuttle and sluggish kinetics, especially with high sulfur loading and under low electrolyte usage. Herein, to facilitate the conversion of lithium polysulfides, nickel-boron (Ni-B) alloy nanoparticles, dispersed uniformly on carbon nanotube microspheres (CNTMs), are used as sulfur hosts for lithium-sulfur batteries. It is demonstrated that Ni-B alloy nanoparticles can not only anchor polysulfides through Ni-S and B-S interactions but also exhibit high electrocatalytic capability toward the conversion of intermediate polysulfide species. In addition, the intertwined CNT microspheres provide an additional conductive scaffold in response to the fast electrochemical redox. The enhanced redox kinetics is beneficial to improve the specific capacity and cycling stability of the sulfur cathode, based on the fast conversion of lithium polysulfides and effective deposition of the final sulfide products. Conclusively, the S/Ni-B/CNTM composite delivers a high specific capacity (1112.7 mAh gs-1) along with good cycle performance under both high sulfur loading (8.3 mg cm-2) and a lean electrolyte (3 μL mgs-1). Consequently, this study opens up a path to design new sulfur hosts toward lithium-sulfur batteries.

Effective hosts of sulfur are essential for the application of lithium-sulfur batteries. However, various refined nanomaterials or carbon-based hosts possess low density, high surface area, and large porosity, leading to undesirable reduction on both gravimetric and volumetric energy densities. Herein, spherical metal oxides with high tap density are introduced as carbon-free hosts of sulfur for the first time. The ternary oxides show a superior synergistic effect of adsorption and electrocatalytic conversion of soluble intermediate polysulfides. Besides, oxide microspheres can build stable conductive frameworks and open channels in porous electrodes for fast transport of electrons and active diffusion of electrolyte. Such a synergistic effect and unique structural feature of porous electrodes are favorable for achieving good utilization and stable cycle performance of the sulfur cathode. Typically, the S/LiNi0.8Co0.1Mn0.1O2 composite exhibits good cycle stability with a low capacity decay rate (0.057% per cycle) during 500 cycles at 0.1 C. Importantly, due to the high tap density (1.81 g cm-3), the S/LiNi0.8Co0.1Mn0.1O2 composite delivers a larger volumetric capacity (1601.9 mAh cm-3-composite), almost 2.3 times of S/carbon composite (689.4 mAh cm-3-composite). Therefore, this work provides a feasible strategy to reach long life and high volumetric capacity of cathode based on metal oxides as sulfur hosts.

We report the fabrication of KCu7S₄/CuxO/Au devices with interfacial CuxO layers of different thicknesses through the spontaneous oxidation of Cu film during deposition. Deposition was conducted with an electron-beam evaporation system under the deposition rate and the chamber pressure of 0.1 A s-1 and 9.8×10-3 Pa, respectively. X-ray diffraction and X-ray photoelectron spectroscopy characterizations reveal that the interfacial CuxO layers mostly comprise Cu₂O and CuO. Electrical characterization reveals that the devices exhibit remarkably thickness-dependent resistive switching behavior. After undergoing an electroforming process under a high compliant current of 1000 μA, the KCu7S₄/16 nm CuxO/Au device exhibits stable bipolar resistive switching behavior with the set voltage of 0.58 V and reset voltage of -0.21 V, whereas the KCu7S₄/32 nm CuxO/Au device only shows a hysteresis loop in the forward voltage regime. These findings are ascribed to the existence of high-insulation CuO, which is difficult to be softly broken down. Therefore, the depositional condition of Cu film and the thickness of the interfacial layer should be appropriately controlled for the effective performance of devices with Cu electrodes. The results may also provide guidance for the improvement of the performance and stability of Cu-based nonvolatile memory devices.

Periprosthetic joint infection (PJI) was the leading cause of artificial joint replacement failure. The aim was to determine antibacterial activity of a novel titanium–copper (Ti–Cu) sintered alloy in vivo. S. aureus suspension was used to construct rabbit models with PJI. The inflammation and infection condition was evaluated by animal survey, bacteria number radiographic examination and histological examination. The levels of white blood cell (WBC), interleukin 6 (IL-6) and C-reactive protein (CRP) were measured to evaluate inflammation. After implantation, serious inflammation with purulent exudate was found in Group II (Ti/Ba), and mild infection was found in Group I (Ci–Ti/Ba). The WBC, IL-6 and CRP levels in Group I were significant higher compared with Group II after implantation. Bacterial incubation results showed that the amounts of S. aureus in Group I were lower compared with Group II after implantation. Radiographic and histological examination also showed that obvious bone destruction was observed in Group II, while not in Group I. Overall, this novel Ti–Cu sintered alloy presented strong antibacterial activity than traditional Ti-based orthopedic materials, suggesting that it has potential to become an ideal antibacterial material for orthopaedic implantation to reduce PJI or implant-related inflammation.

Standards GB 150.3-2011 and JB4732-1995 (Confirmed in 2005) provide design methods for the cylindrical pressure vessels with spherically dished head under internal pressure. It is available for the ratio of the internal pressure p to the allowable stress Sm, p/Sm≥0.002. Engineers desire the design curves for p/Sm

Giant liposome is an important lipid structure widely used in biological and medical fields. In its main preparation method, electroformation, many influencing factors must be optimized for good effect. How to collect the desired giant liposomes is another major issue. In this work, a microchip with a reactor chamber array was used to study the influences of multiple parameters, and a suitable condition could be achieved rapidly and efficiently. A tailor-made collection chamber was also integrated on the chip. Based on the multifactor and multilevel orthogonal experiment, optimal conditions of the lipid solution, buffer solution, and electric signal were achieved with high efficiency. More than one thousand giant liposomes could be formed in each microscale reactor chamber, and most of them were unilamellar. The on-chip collection ratio of giant liposome carriers could also approximate to 40%.

Biosurfactants exhibit outstanding interfacial properties and unique biological activities that fairly related to their self-assembly in solutions and at interfaces. Computational simulations provide structural details of biosurfactant aggregates at the molecular level relevant to thermodynamic properties, but the understanding of kinetics of self-assembly remains limited due to lower simulation efficiency. In this work, a coarse-grained model has been developed for microbial lipopeptide surfactin, and surfactin monolayer at the octane/water interface and micelle in aqueous solution were studied using molecular dynamics simulations. Interaction parameters were optimized and validated by comparing with results obtained from experiments and atomistic molecular dynamics simulations. In particular, self-assembly of surfactin in aqueous solution was studied using the optimized parameters. Results showed that coarse-grained simulations well reproduced structural properties of surfactin monolayer and micelle and the molecular behavior such as surfactin orientation and conformation. Self-assembly features of surfactin in different stages have been captured, and the aggregation numbers of dominant clusters were in accordance with experimental data. This report suggested that the present coarse-grained model and interaction parameters allowed surfactin simulations over longer timescales and larger systems, which provide insights into characterizing both the kinetics of surfactin self-assembly and the adsorption of surfactin onto varying interfaces.

Biocompatible nanoscale probes for sensitive detection of paramagnetic species and molecules associated with their (bio)chemical transformations would provide a desirable tool for a better understanding of cellular redox processes. Here, we describe an analytical tool based on quantum sensing techniques. We magnetically coupled negatively charged nitrogen-vacancy (NV) centers in nanodiamonds (NDs) with nitroxide radicals present in a bioinert polymer coating of the NDs. We demonstrated that the T1 spin relaxation time of NV centers is very sensitive to the number of nitroxide radicals, with a resolution down to ~10 spins per ND (detection of approximately $ 10^-23 $ mol in a localized volume). The detection is based on T1 shortening upon the radical attachment and we propose a theoretical model describing this phenomenon. We further show this colloidally stable, water-soluble system can be used dynamically for spatiotemporal readout of a redox chemical process (oxidation of ascorbic acid) occurring near the ND surface in an aqueous environment under ambient conditions., Comment: 26 pages (plus 18 pages of supporting information), 3 figures (plus 8 figures in supporting information)

The mushroom growth of portable intelligent devices and electric vehicles put forward higher requirements for the energy density and safety of rechargeable secondary batteries. Lithium-ion batteries using solid-state electrolytes are considered to be the most promising direction to achieve these goals. This review summarizes the foremost challenges in line with the type of solid electrolyte, provides a comprehensive overview of the advance developments in optimizing the performance of solid electrolytes, and indicates the direction for the future research direction of solid-state batteries and advancing industrialization.

Corn stalk fibre reinforced nonasbestos environment-friendly friction composite materials have been fabricated, and their physical, mechanical, and tribological properties are characterized. The tribological properties of the friction composites were evaluated following GB5763-2008 norms on a constant-speed-type friction tester. The experimental outcome reveals that the content of corn stalk fibre has a noteworthy impact on the tribological, mechanical, and physical properties of the friction composites. Specifically, the friction composite with a content of 7% exhibited excellent friction and wear properties. The worn surface morphology of friction composites was further investigated using a scanning electron microscope. It was found that the corn stalk fibre content greatly affected the tribological properties of the friction composites.

Lithium metal is recognized as the “Holy Grail” of anode materials for high-energy-density batteries. However, the application of the lithium anode is seriously hindered due to its instability especially during the large-capacity lithium stripping/plating process. In this study, a dimensionally stable Li composite electrode is fabricated by electrodepositing lithium on Ag-modified Cu foam. The Li-Ag alloy formed during the initial plating shows micro-structural affinity to lithium and promotes the subsequent uniform Li stripping/plating on the Cu skeleton. The symmetric cell with Li/Ag-modified Cu composite electrode shows much-improved stability as compared to both the Li/3D Cu composite and Li plate electrodes. By investigating the electrochemical performance of the full cells with Li4Ti5O12 cathode, we find the interface stability of the Li composite electrode is deteriorated because of the increase of specific surface area. This work indicates that both dimensional and interface stabilities of lithium anodes are important for fabricating practical secondary lithium batteries.

A continuum-discrete coupled modelling approach is developed in LS-DYNA to simulate complicated fragmentation phenomena of concrete under high strain-rate impact, using realistic mesoscale finite element models converted from micro X-ray computed tomography (XCT) images. In this approach, the Johnson Holmquist concrete (JHC) constitutive law based on continuum damage plasticity is used to simulate plasticity and crushing of elements, while a node-split method with contact is used to simulate discrete fracture between elements. This avoids using the popular element erosion technique, which suffers from unreal losses in mass and energy, especially under dynamic loadings with high strain rates. After the new approach is validated, extensive Monte Carlo simulations (MCS) of 93 2D FE models and one 3D model from XCT images of a 37.2mm concrete cube, consisting of aggregates, mortar, interfaces, and pores, are conducted under compressive impact with strain rates ranging from 0-1000/s and different end friction conditions. It is demonstrated that the developed modelling approach can simulate realistic failure mechanisms such as discrete fracture propagation under strain rates of 0-200/s and immediate crushing, fragmentation and prilling under higher strain rates of 500-1000/s. The predicted compressive dynamic increase factor of strength (CDIF)–strain rate curve is found well within the range of experimental data and very close to other empirical curves. Quantitative statistical calculations show that the meso-structure is the main contributor to the dynamic strength increase or reduction when the strain rate is lower than 10/s, but the inertial effect becomes dominant when the strain rate is higher than 100/s. The end friction confinement makes only 3-5% difference.

Since the gradation of cement-slag has significant influence on its properties, the optimal gradation of cement-slag was studied by imitating with limestone powder. From experimental results of the porosity and fluidity of limestone power and on the base of the RRB equation, the optimal gradation area was got and its rationality was confirmed by experimental results of cement-slag.

The 3D configuration of graphene materials has been intensively investigated due to their novel properties in biomedical, electrical and optical applications. But few reports have been intentionally carried out to understand the biological influence of 3D graphene materials so far. Herein, we presented an evaluation of the in vitro cytotoxicity of 3D graphene sheets fabricated by carbonization of polydopamine (PDA) films on a template of aligned nanopore arrays (NPAs) on a stainless steel surface. The prepared 3D graphene sheets with a thickness of ∼20 nm displayed a nanoporous architecture that can be readily tuned by the NPA template to control the morphology of the 3D configuration. The in vitro toxicity of the nanoporous 3D graphene sheets with pore sizes of ∼50 nm and ∼240 nm was evaluated using NIH-3T3 fibroblasts as the representative mammal fibroblast cell type. The NPA structure exhibits enhanced properties in cell attachment, spreading, proliferation, and the assembly of focal adhesions and actin filament associated proteins. Morphology-dependent cytotoxicity aroused by the 3D graphene configuration should be attributed to the engulfment of the carbon nanospheres embedded in the 3D configuration and the lack of both focal adhesions and actin filament associated proteins assembling at the nanoscale.

Realizing high energy density is the desirable target of the research and development for lithium−sulfur battery. However, the demands of high sulfur content in composite, high sulfur loading in electrode, and low electrolyte usage are likely excessive for reaching both high gravimetric and volumetric capacities of sulfur cathode with conventional inactive hosts of sulfur. Herein, in order to effectively drive the conversion of sulfur, niobium tungsten oxide (Nb18W16O93) microspheres are adopted as electroactive host in the similiar electrochemical window to sulfur. As expected, Nb18W16O93 shows good electrochemical activity for lithium storage, and strong adsorption toward polysulfides. In particular, the in-situ electrochemically lithiated oxide in the discharge process can serve as good electrocatalyst and lithium-transfer bridge, facilitating the conversion of both the solid sulfur and soluble polysulfides. Correspondingly, the new lithium-transfer mechanism on Nb18W16O93 endows the sulfur cathode a high areal capacity (19.19 mAh cm−2) under both high sulfur loading (16.94 mg cm−2) and low electrolyte/sulfur ratio (4.5 μL mg−1). In addition, the sulfur-based composite with high tap density (1.56 g cm−3) shows a desired volumetric capacity (1605.3 mAh cm−3-composite), almost 1.9 times of that for the conventional S/carbon composite. This work provides a new perspective for understanding the electroactive hosts in lithium−sulfur battery.

Lithium–sulfur battery is recognized as one of the most promising next-generation energy storage devices. However, the low specific capacity and inferior cycling stability of cathode are real bottlenecks in practical lithium–sulfur battery, owing to the low sulfur content and tap density of cathode with light-weight and nonpolar carbon host materials. In this study, conductive RuO2 stacking microspheres are designed and demonstrated as sulfur immobilizer for lithium–sulfur battery. The stacked RuO2 microspheres exhibit not only good conductive framework for both the transport of electrons and diffusion of electrolyte, but outstanding electrocatalytic activity for the conversion of lithium polysulfides. Moreover, the polarity of RuO2 is helpful to trap and confine soluble polysulfides during cycling. With a high tap density of 1.4 g cm−3 and high sulfur content of 81.8 wt%, the S/RuO2 composite delivers a high gravimetric and volumetric capacity of 985 mAh g−1-composite and 1360 mAh cm−3-composite at 0.2 C rate, respectively. Resulting from the fast redox kinetics, an excellent rate capability of 479 mAh g−1-composite can be also obtained at 5 C rate. Overall, this work unfolds a potential strategy to realize the combination of high energy density and improved cycling stability of lithium–sulfur battery.

TiO 2 /WO 3 nanocomposite film was deposited on anodized stainless steel by one step hydrothermal reaction. Polished stainless steel foil was anodized to form nanopore arrays on the surface that is favorable for the immobilization of photocatalyst. The TiO 2 /WO 3 nanocomposite film prepared in 0.01 mol/L (NH 4 ) 2 TiF 6 and 0.0066 mol/L Na 2 WO 4 solution at 120 °C for 3 h exhibits the maximum photocatalytic activity, which is five times higher than that of pure TiO 2 film and eight times higher than that of pure WO 3 film. As compared with the pure TiO 2 film, the main absorption edge of the WO 3 /TiO 2 nanocomposite film shifts toward visible region and the absorption intensity is obviously improved. The nanocomposite film has a preferable crystallinity of anatase TiO 2 and the monoclinic WO 3 , as revealed by X-ray diffraction and X-ray photoelectron spectroscopy. Scanning electron microscopy images show that the nanocomposite film is homogenous in size distribution and uniform in morphology. The high resolution transmission electron microscopy images further demonstrate the formation of mixed crystal between WO 3 and TiO 2 nanoparticles. The excellent photocatalytic activity of the nanocomposite film should be attributed to the formation of heterojunction between TiO 2 and WO 3 nanoparticles that can facilitate the separation of photo-generated electron–hole pairs.

In this paper, the contrast test has been done on the brake linings that have been made by water granulating technology. As a result, by contrast with the brake linings that have been done at the same material and producing technology, it was preliminary demonstrated that the apparent porosity of the brake linings that have been made by the granulating technology could be enhanced greatly, so on the hot-pressing process, products exhausting has been easy, the die cavity volume could be decreased, the hot-pressing time could been shorten, the production efficiency could be enhanced, the natural frequency of the braking lining could be reduced, the possibility of the braking noise could be decreased.

In order to provide a new technique for macrophytes use, this study evaluated the effect of biomass content on properties of biomass briquetting. Take lime as the binder, the best addition of biomass was 45%. In such case the drop strength of giant reed and reed briquetting reached maximum 55% and 74% respectively, and water impermeability reached minimum 15% and 7% respectively. Calorific value of biomass briquetting was between 11.1 MJ/kg and 14.9 MJ/kg and ash content was between 38.6% and 45.5%. Take giant reed briquetting as the example, 25% of money could be saved if briquetting replaced coal and people in Nansi Lake would get $159,333,333 a year. Also biomass briquetting could bring some environmental benefit including purifying water, slowing the greenhouse problems and acid rain. This study could provide a support for wetland restoration of the ecosystem, water quality, and the improvement of the economic benefits.

Trimaran, as a high performance ship, its special ship form is different from regular monohull ship. The particular characteristics of longitudinal and transverse wave loads are concerned greatly by ship structure designers. Theoretical methods for forecasting the wave loads of trimaran are under developing. And the relative comprehensive model test study of trimaran’s wave loads is rare in the publication. In this paper, the trimaran model test had been carried out in the tank. According to similarity theory and simulation of stiffness, a scale model of trimaran with measurement system had been manufactured. Then the segmented model had navigated in regular waves of different sea conditions. Through analysis of the experimental data, the wave loads characteristics of this trimaran are presented. A comparison of test results and theoretical values is also made to show the similarities and differences. This study can provide some useful information for further design of high-speed trimaran in the point of wave loads, which maybe a reference for research of trimaran.

The machine of friction material on mixing and granulation was prepared. In this text, it is showed the working principle、structure parameter and composing parts and means of the machine. It has the character of the inexpensiveness、compactness、sensitivity、safety and convenience、adjustable angle、mixing uniformity and efficiently. With the application of the friction material for disposing, the research will be done from the material to structure.

AZ91D magnesium alloy chips, which were directly collected on the spot of machining process, were recycled to prepare billet via hot pressing for semi-solid processing. The semi-solid microstructure evolution of the billet during reheating was investigated. The results indicate that there are three stages during reheating to semi-solid state: the dissolution of Mg17Al12 and diffusion of Al into α-Mg matrix, the melting of the region with high content of solute and formation of isolated solid particles, and spheroidization and growth of solid particles. Meanwhile, a number of entrapped liquid droplets form within solid particles. In addition, the number and size of entrapped liquid droplets rely on the holding time in the semi-solid temperature range. With increasing isothermal holding time, the solid fraction remains unchanged when the solid-liquid system reaches the dynamic equilibrium at last, while the solid particles become more globular and the average size of solid particles increases owing to the decreasing of interfacial energy and the effect of interfacial tension.

In this paper, chip recycling technology combined with SIMA method which is called CR-SIMA method was adopted to prepare semi-solid billets. AZ91D magnesium alloy was refined by Er and its microstructural evolution was investigated during semi-solid isothermal treatment. The results show that Er can improve the feature of cast structure and decrease the grain size. Moreover, the γ-Mg17Al12 phase is well refined and disperses in the α-Mg matrix. A semisolid microstructure with small and spheroidal primary particles can be obtained after partially remelting. With increasing heating temperature, the dissolution of eutectic Mg17Al12 phase first took place, resulting in the primary dendritic grains coarsening into interconnected non-dendritic grains. With heating continuously, the residual interdendritic γ-Mg17Al12 at the edges of the primary grains melted in succession and the primary grains separated into small polygon grains. During the semi-solid isothermal treatment, the amount of liquid increased until the solid-liquid system reached its equilibrium state. At the same time, owing to the decreasing of interfacial energy, the grains gradually spheroidized and began to grow with a further increasing of the holding time.

The strain-induced melt activation (SIMA) process is one form of the thixoforming for aluminum alloy. However, the non-uniform stress distribution restricts its application. In order to avoid this problem, a chip recycling strain-induced melt activation (CR-SIMA) process has been developed to prepare semi-solid billet. Microstructures of semi-solid ADC14 aluminum alloy billets heated to different temperatures and held for various times were investigated. The typical semi-solid microstructure with globular solid particles distributed in the liquid matrix is obtained in the temperature range of 560 and 565oC. The spheroidizing mechanism of ADC14 alloy prepared by the CR-SIMA process was studied. It was found that the severe deformation not only influences the solidification of spherical α-Al particles, but also affects the morphology of primary Si. The primary Si phases become tiny particles and distribute around the α-Al particles.

In this paper, Co–Al–CO 3 layered double-metal hydroxides (CAC-LDHs) were prepared by co-precipitation method and characterized by XRD, FT-IR, TG-DSC, SEM. In addition, their frictional features were evaluated by four-ball friction tester, gear tester and air compressor. The results showed that optimized synthetic conditions of CAC-LDHs were water–ethanol solution media with Co/Al mol ratio of 3:1, crystallization temperature of 120 °C and crystallization time of 5 h. The LDHs have perfect crystals with hexagonal lamella structures. Most crystallites have disk diameter of 150 – 200 nm and thickness of 20 nm. The d -spcing and gallery height of CAC-LDHs were 0.77nm and 0.29nm, respectively. Total specific surface area of the sample is 97 m 2 /g and pore volume is 0.14 cm 3 /g. As a lubricant, CAC-LDHs can significantly reduce friction coefficient (49.1%) and wear of friction pairs. They can also reduce temperature of lubrication oil (7.4–7.7%) and energy consumption of driving motor (4.8–7.0%). Accordingly, CAC-LDHs may broadly be used as lubrication and anti-frictional materials.

Based on the classical polarization theory, we studied and specified the physical mechanism of the electric-field-induced (EFI) Pockels effect and optical rectification in the space charge region of a near-intrinsic silicon sample with the planar capacitor structure. Especially, the effect of the applied DC bias on these EFI effects was investigated. The results show that the electro-optic signal from Pockels effect in silicon linearly increases with the applied DC voltage and the modulating voltage, and the signal of optical rectification is linearly enhanced by the DC bias as well, but the polarization characteristic of optical rectification does not vary. The enhancement of these EFI effects is mainly owed to the strengthening of the built-in field and the extension of the space charge region in the silicon sample. The Kerr effect of silicon was also detected and contrasted against the EFI Pockels effect, and it is verified that the EFI Pockels effect is much stronger than the Kerr effect in the silicon sample. These EFI effects are significant for the development of silicon photonics or silicon optoelectronics.

The experiments were conducted in a horizontal multiphase flow test loop (50mm inner diameter, 40m long) and the cross-correlation technology was used for the study of the characteristics of the interfacial wave velocity about two types of annular flow regimes (AN║DO/W and AN║DW/O) for gas-oil-water three-phase flow. The results show that the interfacial wave velocity on the liquid film of AN║DO/W flow pattern and AN║DW/O flow pattern all increases with the increase of gas superficial velocity and liquid superficial velocity on the condition of fixed ratio of oil and water flow rates, but the difference is that the increase is a linear monotonic increase for AN║DO/W flow pattern and a non-linear increase for AN║DW/O flow pattern, and the liquid superficial velocity makes a larger contribution than the gas superficial velocity. The interfacial wave velocity also increases with the increase of input water cut in liquid at different gas superficial velocities under the conditions of liquid superficial velocity fixed.

Semi-solid metal processing is a new developing technology. This processing has a more advanced technology than traditional ones such as forming and casting. The quasi-spherical grain has been formed by recrystallization of the dendrites during reheating in semi-solid state. The strain-induced melt activation is simple and does not need expensive equipment for preparing semi-solid billets. In this paper a modified method was proposed based on the strain-induced melt activation process. The microstructure and mechanical properties of ADC12 aluminum alloys prepared by the modified strain-induced melt activation process were studied. Different levels of heating temperatures and holding times were used in this investigation. The results of heating experiment revealed that the optimum heating temperature, isothermal holding time and average size of particles were 828 K, 1800 s and 70 μm, respectively. The results of isothermal treatment showed that the size of spherical particles increased linearly with extending the holding time at the 828 K. In the meantime the quantity of particles showed the parabola descent. These phenomena are in accordance with the Lifshitz–Slyozov–Wagner theory and Ostwald ripening.

A finite element method was developed to reveal the thermal characteristics of concrete with a cooling pipe, and the influence of cooling pipe on thermal field was calculated by the coupled fluid flow and solid heat transfer method. Temperature distribution along the pipeline was calculated and the mean Nusselt numbers on each section in the cooling pipe also were obtained. Numerical results show that the flow field and the temperature distribution were very complexly and the heat transfer was severely attenuated in the bend position, the outboard temperature of pipe was higher than the inboard temperature. In addition, in order to study the effect of the cooling pipe on thermal distribution, the temperature of different positions at the hydration time were compared with the no cooling results. The present results could be helpful to predict the temperature cracks in structure engineering.

AZ91D magnesium alloy chips were adopted to prepare semi-solid billets. The chips were subjected to a series of isothermal treatments for various holding times at 783-843 K after being compressed into billet at 523 K. The semi-solid microstructure of AZ91D magnesium alloy containing spherical solid particles was studied. The effects of reheating temperature and holding time on microstructures were investigated. And the semi-solid forming mechanism was discussed. The result shows that semi-solid billets with highly spheroidal and homogeneous grains can be prepared from chips by strain induced melt activation(SIMA) method. Meanwhile, it is found that increasing the heating temperature can accelerate the spheroidizing process and reduce the solid volume fraction. With the increase of the holding time, the solid particles become more globular, the grains grow slowly and the solid volume fraction slightly changes. At the same time, owing to the decrease of interfacial energy, the intragranular liquid phases form by the diffusion of solute atoms, the grain boundaries melt and grains separate from each other during the isothermal treatment. The grains gradually spheroidize and begin to merge with a further increase of the holding time. It is considered that the semi-solid forming process includes three stages: the recrystallization and the growth of grain stage, the semi-solid microstructure forming stage controlled by the diffusion of solute, and the spheroidization of solid particle stage controlled by the liquid-solid interface tension.

Silica aerogels were synthesized from the industrial fly ash by ambient pressure drying method. The process consists of two stages, preparation of sodium silicate solution from fly ash by hydrothermal reaction with sodium hydroxide, and synthesis of porous silica aerogels from the obtained sodium silicate solution. Silica wet gels were formed by vitriol-catalysis or resin-exchange-alkali-catalysis of the obtained sodium silicate solution. The trimethylchlorosilane(TMCS)/ethanol(EtOH)/hexane mixed solution was used for solvent exchange/surface modification of the wet gel so as to obtain porous silica aerogels via ambient pressure drying. The results indicated that the synthesized silica aerogels were lightweight and hydrophobic. The BET specific surface area, pore volume and average pore diameter were 362.2–907.9 m 2 g − 1 , 0.738–4.875 cm 3 g − 1 , and 7.69–24.09 nm respectively. Particularly, the synthesized silica aerogels by resin-exchange-alkali-catalysis method showed uniform mesoporous structure, and had much higher specific surface area (907.9 m 2 g − 1 ) and pore volume (4.875 cm 3 g − 1 ) than that of by vitriol-catalysis process.

A semi-solid microstructure of ADC12 aluminum alloy containing spherical solid particles was studied. A new strain-induced melt activation (SIMA) process was proposed. In the treatment, chips were cut from ADC12 ingot by lathe machining and the plastic deformation was produced through cutting. The chips were put into a metal mold and compressed into a billet at 473 K. The microstructures of chip and billet were studied. The effect of the isothermal treatment on the semi-solid microstructure evolution of ADC12 aluminum alloy prepared by the new method was analyzed. A series of heating treatments were carried out from 823 to 838 K. The effects of heating temperature on microstructures were studied. The experimental results show the ADC12 aluminum alloy prepared by the new method can reap homogeneous and spherical grains at 828 K. The average grain size is about 82 μm. Also, the grain microstructure obtained by the present process is better than the traditional one. These results prove that the ADC12 aluminum alloy can be applied to semi-solid processing with the new SIMA method.

By direct quenching or post-annealing followed by quenching, we have successfully obtained a series of KxFe2-ySe2 samples with different properties. It is found that the samples directly quenched in the cooling process of growth show superconductivity and the one cooled with furnace is insulating even though their stoichiometries are similar. The sample cooled with furnace can be tuned from insulating to superconducting by post-annealing and then quenching. Based on the two points mentioned above, we conclude that the superconducting state in KxFe2-ySe2 is metastable, and quenching is the key point to achieve the superconducting state. The similar stoichiometries of all the non-superconducting and superconducting samples indicate that the iron valence doesn't play a decisive role in determining whether a KxFe2-ySe2 sample is superconducting. Combining with the result got in the KxFe2-ySe2 thin films prepared by molecular beam epitaxy (MBE), we argue that our superconducting sample partly corresponds to the phase without iron vacancies as evidenced by scanning tunnelling microscopy (STM) and the insulating sample mainly corresponds to the phase with the $\sqrt{5}\times\sqrt{5}$ vacancy order. Quenching may play a role of freezing the phase without iron vacancies., 9 pages, 7figures, this article is a new version of arXiv:1103.1347 with new data added

The electro-optic effects in silicon include Kerr effect, plasma dispersion effect, and Franz-Keldysh effect etc.. Silicon does not have the linear electro-optic effect in the bulk because of the inversion symmetry, which restricts the development of the silicon-based optoelectronics and silicon photonics. However, the electric field can destroy the inversion symmetry of silicon, and produce so-called electric-field-induced linear electro-optic effect. In intrinsic or near-intrinsic silicon, these electro-optic effects exist simultaneously. In this paper, a transverse electro-optic modulation system was designed to detect these electro-optic effects. The electric-field-induced linear electro-optic effect was demonstrated in the space charge region of silicon sample and distinguished from Kerr effect based on the different frequency response. The relationship between the linear electro-optic signal and the azimuth angle of the analyzer was measured too, which was used for distinguishing the electric-field-induced linear electro-optic effect from the plasma dispersion effect. The results showed that the electric-field-induced linear electro-optic effect was stronger than Kerr effect and the plasma dispersion effect in the near-intrinsic silicon samples.