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Multiferroic devices have attracted renewed attention in applications of photovoltaic devices for their efficient carrier separation driven by internal polarization, magnetization, and above-bandgap generated photovoltages. In this work, Zn2SnO4-based multiferroic Bi6Fe1.6Co0.2Ni0.2Ti3O18/Bi2FeCrO6 (BFCNT/BFCO) heterojunction photoelectrodes were fabricated. Structural and optical analyses showed that the bandgap of the spinel Zn2SnO4 is ∼3.1 eV while those of Aurivillius-type BFCNT and double-perovskite BFCO are 1.62 and 1.74 eV, respectively. Under the simulated AM 1.5G illumination, the as-prepared photoelectrodes delivered a photoconversion efficiency (η) of 3.40% with a short-circuit current density (Jsc), open-circuit voltage (Voc), and fill factor (FF) of 10.3 mA·cm-2, 0.66 V, and 50.4%, respectively. Analyses of adjustment of an applied electric and magnetic field on photovoltaic properties indicated that both magnetization and polarization of multiferroics can effectively tune the built-in electric field and the transport of charge carriers, providing a new idea for the design of future high-performance multiferroic oxide photovoltaic devices.

The ability to mutually regulate polarization and magnetization, highly desirable for future multifunctional devices, remains elusive despite extensive investigations. In this work, a concept of mutual regulation of ferroelectric and ferromagnetic orders via stress analysis of dipoles was proposed and the idea was demonstrated in a 2-2 type multiferroic Bi6Fe1.6Co0.2Ni0.2Ti3O18/Bi2FeCrO6 heterostructure fabricated by a sol-gel technique followed with a rapid thermal proces. Both ferroelectricity, ferromagnetism and magnetoelectric coupling of the composite thin film were studied by macro- and microscale measurements. It demonstrated that a reversible change in domain structure does occur while exerting a stress on dipoles by different applied fields, wherein the (inverse)-piezoelectric effect, magnetostriction, Lorentz force, and Hall effect play an important role in deflection of dipoles and evolution of domains, and thus the regulation of polarization and magnetization, making it attractive for novel memories.

Here, we report facile fabrication of two-dimensional (2D) Pd nanosheet (NS)-supported zero-dimensional (0D) Au nanoparticles via galvanic replacement. In the synthesis, the surface-clean Pd NSs premade not only acted as a sacrifice template for replacing Pd atoms by Au3+ ions, but served as a support substrate to support Au nanoparticles. The morphology, structure, and composition of products relied on the Au/Pd feed atomic ratio. Interestingly, the as-obtained 0D/2D AuxPd100-x (x = 4.5, 9.8, and 21) nanocomposites showed remarkably enhanced peroxidase-mimic catalysis in the model oxidation reaction, which followed the typical Michaelis-Menten theory. Compared to Pd NSs, the enhanced catalysis of AuxPd100-x was closely related to both the increased specific surface area and the modified electronic structure of Pd NSs, which resulted in a change in the catalytic pathway, that is, from hydroxyl radical generation to rapid electron transfer. The work provides a simple yet efficient avenue to build highly efficient heterogeneous catalysts based on metallic NSs, as exemplified by the superior nanozyme activity of 0D/2D bimetallic nanostructures for glucose detection.

Multiferroics are being studied increasingly in applications of photovoltaic devices for the carrier separation driven by polarization and magnetization. In this work, textured black silicon photovoltaic devices are fabricated with Bi6Fe1.6Co0.2Ni0.2Ti3O18/Bi2FeCrO6 (BFCNT/BFCO) multiferroic heterojunction as an absorber and graphene as an anode. The structural and optical analyses showed that the bandgap of Aurivillius-typed BFCNT and double perovskite BFCO are 1.62 ± 0.04 eV and 1.74 ± 0.04 eV respectively, meeting the requirements for the active layer in solar cells. Under the simulated AM 1.5 G illumination, the black silicon photovoltaic devices delivered a photoconversion efficiency (η) of 3.9% with open-circuit voltage (Voc), short-circuit current density (Jsc), and fill factor (FF) of 0.75 V, 10.8 mA cm−2, and 48.3%, respectively. Analyses of modulation of an applied electric and magnetic field on the photovoltaic properties revealed that both polarization and magnetization of multiferroics play an important role in tuning the built-in electric field and the transport mechanisms of charge carriers, thus providing a new idea for the design of future high-performance multiferroic oxide photovoltaic devices., Regulation of photovoltaic response in multiferroic oxide BFCNT/BFCO heterojunction black silicon photovoltaic devices by polarization and magnetization.

During the planar lightwave circuit (PLC) splitter manufacturing process, high precision is essential. Controlling machining precision is extremely difficult during the high-speed-and-precision dicing process, which is empirically related to the rotational speed, static diameter and elastic modulus of diamond dicing blades and other factors. However, the effect of changes in the outer diameter of blades on machining precision has been disregarded in the PLC manufacturing process. In this research, we proposed a dynamic diameter (Dd) for describing changes in a blade’s outer diameter during the high-speed machining process. Dd is positively correlated with machining precision. Here, we derived a formula for calculating Dd that is related to the rotational speed, static diameter, elastic modulus, Poisson’s ratio, density, cutting length and radial wear rate of diamond dicing blades. Furthermore, a series of experimental Dd values was obtained by changing the rotational speed, static diameter and elastic modulus of diamond dicing blades. These values are highly consistent with the calculated results. Our findings not only provide clues to compensate for diameter during high-speed-and-precision dicing process, but also offer guidelines for a new design route of diamond tools.

A tetradentate 8-hydroxyquinoline-based acyl hydrazone ligand (HL1 = 8-hydroxyquinoline-2-carboxaldehyde-(aminourea)hydrochloride) was elaborately used to construct a mononuclear dysprosium complex DyCl3HL1·CH3OH (1) with a nearly ideal pentagonal bipyramid coordination geometry (D5h) surrounding the Dy(iii) ion to achieve the significant performance of single-molecule magnets (SMMs). Meanwhile, the isolated high local symmetry center was successfully kept intact and further bridged to a series of double bipyramid systems by two phenolic oxygen atoms of the acyl hydrazone ligands (HL1 and HL2 = 8-hydroxyquinoline-2-carboxaldehyde-(benzoyl)hydrazine), with the formulae [Dy2Cl4(L1)2(CH3OH)2]·4C5H5N (2) and [Dy2Cl4(L2)2]·2CH3CN (3). In addition, the monodentate co-ligand anion was replaced by a larger sterically hindered ligand and a bidentate monovalent β-diketonate anion to generate [Dy2(tfo)4(L2)2(EtOH)2] (4), [Dy2(tta)4(L2)2(EtOH)2]·2(EtOH) (5) and [Dy2(dbm)4(L2)2(EtOH)2] (6) (tfo = trifluoromethanesulfonic acid, dbm = dibenzoylmethane, tta = 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione) with eight-coordinate geometry. Strikingly, the dynamic magnetic measurements revealed that complexes 1-3 did not display the expected significant SMM performance albeit they had high local symmetry. In combination with ab initio calculation, the alignment of the coordination symmetric axis and the magnetic easy axis dominates the molecular magnetic anisotropy, and the magnetic easy axis could be modulated by the distribution of coordination atoms with different electrostatic properties.

In this paper, the fiber optic extrinsic Fabry-Perot interferometer (EFPI) sensor with a beam-supported membrane structure was designed and developed to detect acoustic emission (AE) signals of partial discharge (PD). Based on the MEMS processing technology, the silicon-On-Insulator (SOI) was used to fabricate the diaphragm structure of the supporting beam and control the Fabry-Perot (FP) cavity length accurately by design of the hole shoulder. Processed diaphragm and its measurement results of size parameters are given, while measurement of FP cavity length by surface profilometer is also shown. At last, experimental results in laboratory show that the developed EFPI sensor with a beam-supported membrane structure is feasible and practical used for PD AE detection.

To improve the electrochemical performance of traditional poly(vinylidene fluoride- co -hexafluoropropylene) [P(VdF-HFP)] based gel polymer electrolyte (GPE), maleic anhydride-grated-polyvinylidene fluoride (MA-PVdF) was introduced to form polypropylene (PP) supported MA-PVdF/P(VdF-HFP) based GPE. Nano-Al 2 O 3 was also incorporated into MA-PVdF/P(VdF-HFP) blend in order to further enhance the comprehensive performance of GPE. The corresponding membranes and GPEs were characterized by porosity, electrolyte uptake, scanning electron microscopy, X-ray diffraction, electrochemical impedance spectroscopy, mechanical test, thermogravimetric analyzer, charge/discharge test and nail penetrates experiment. It is found that the performances of GPEs are significantly improved when the mass ratio of MA-PVdF to P(VdF-HFP) is 1:6. Doping 10 wt% nano-Al 2 O 3 further influences the characterization of selected membranes and GPE, in which the electrolyte uptake is enhanced from 128 to 192%, the ionic conductivity of corresponding GPE is improved from 2.39×10 −3 S cm −1 to 3.84×10 −3 S cm −1 , the mechanical strength increases from 6.34 to 6.98 N, the thermal decomposition temperature from 260 °C to 420 °C. Thus, the full battery LiCoO 2 | GPE | Artificial graphite exhibits good rate and cycling performances. After 100 cycles, the discharge capacity of the cell retains 97.2% of original one for the Al 2 O 3 doped GPE, while 95.6% for the GPE without nano-Al 2 O 3 and 93.2% for P(VdF-HFP) based GPE. Additionally, the safety performance of full charged battery is enhanced, in which the highest temperature is rapidly declined from 250 °C for the polypropylene (PP) membrane to 104 °C for PP supported MA-PVdF/P(VdF-HFP)/Al 2 O 3 membrane in the nail penetrates experiment.

Soft magnetic material FeCoV is sensitive to magnetic field and its cost is lower than giant magnetostriction materials (Terfenol-D et al.). In the present investigation Pb (Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) with different thickness and FeCoV laminate with 0.8mm thickness were assembled into layer structure to study the effect of the PMN-PT volume fraction on the magnetoelectric coefficient of PMN-PT/FeCoV laminate composites. The ME coefficients and voltages have been characterized in the longitudinally magnetized and transversely polarized mode. The measurement was conducted under a static magnetic field superimposed with an alternating magnetic field. The influences of the static and the alternating field strength were discussed. The peak ME coefficient was obtained at 430 Oe. With the volume fraction of PMN-PT increased, the ME coefficient decreased within the experiment fraction. It can be explained by the module of M.I.Bichurin. A linear relationship was observed between the magnetoelectric voltage and the alternating field strength under a static field of 400 Oe. The ME voltage decreased when the PMN-PT volume fraction increased in the experiment fraction.

Interfacial properties and energy-band alignment of annealed AlN dielectric films on Si-face 4° off-axis 4H–SiC substrates were characterized and demonstrated by x-ray photoelectron spectroscopy (XPS) and current-electric field (I–E) measurements. The XPS results reveal that the Al–O bonds and the silicon suboxides can convert into more stable Al–N bonds and Al–O–Si bonds at the AlN/4H–SiC interface under 1000 °C annealing. The variations in both oxygen-rich composition and the crystallinity in AlN make annealing-dependent conduction band offsets of as-deposited and annealed AlN/4H–SiC to be 1.36 eV and 1.20 eV, respectively. Meanwhile, I–E measurements separately yield the occurrence of the Fowler–Nordheim (FN) tunneling and space-charge-limited conduction in as-deposited and annealed metal-insulator-semiconductor capacitors, corresponding to lower barrier heights of 0.92 eV and 0.54 eV, respectively. The reason for the energy-band shift between I–E derivations and the XPS results was analyzed and demonstrated together. These results can provide considerable insight into the energy-band alignment of AlN as gate dielectric or passivation layers on 4H–SiC based devices.

The microstructure was fabricated on LED surface with a picosecond laser. The measurement of far field light distribution from processed LED agrees with the simulation. Such fabrication may have potential application for LED light distribution.

The energy transfer dynamics by femtosecond time-resolved fluorescence spectroscopy in C-phycocyanin hexamer was studied. The energy transfer pathways in the hexamer were identified by deconvoluting the fluorescence decay curve at different detection wavelengths.

The effect of artificial aging on the corrosion resistance of 2024 Al alloy was investigated by field emission scanning electron microscope (FE-SEM) and accelerated corrosion test. For comparison, the solution treatment followed by air-cooled and water-quenched samples were also researched. Accelerated corrosion test revealed that the corrosion resistance of the alloy strongly depended on artificial aging times, and the weight gain of the aged alloy increased first and then decreased with increasing the aging times, and a maximum value was found at peak aged condition. The air-cooled sample had the highest weight gain while the water-quenched one had the lowest weight gain among all the samples. The corrosion morphologies showed that pitting and localized intergranular corrosion were the main corrosion forms for the air-cooled and aged 2024 Al alloys. However, only pitting corrosion took place on the water-quenched samples. The pitting and intergranular corrosion resulted from galvanic corrosion between secondary particles and matrix Al, and between grain boundary precipitates and matrix Al, respectively.

The effect of artificial aging on the corrosion properties of 6063 Al alloy was investigated by optical microscope, field emission scanning electron microscope (FE-SEM) and accelerated corrosion test. Accelerated corrosion test revealed that the corrosion resistance of the alloy strongly depended on artificial aging times, and the corrosion weight gain curve of the aged alloy was greatly in agreement with that of hardness vs. aging times, showing that the lowest corrosion resistance was exhibited at peak aged condition. It is found that pitting is the main corrosion form for the 6063 aluminum alloy aged with different times at 210°C, and slight intergranular corrosion is also found at peak hardness. It is believed that pitting results from galvanic corrosion between Al9Fe2Si2 particles and matrix Al while intergranular corrosion results from galvanic corrosion between Mg2Si and matrix Al.

The structural properties, mechanical behaviors and electronic structures of FeB 4 and FeB 2 have been studied systematically by first-principles calculations considering the strong correlation effect. Our results show that FeB 4 is incompressible and hard, but the recently reported superhard feature [Phys. Rev. Lett. 111 (2013) 157002] is not supported by the present calculations. Interestingly, we find that FeB 2 rivals FeB 4 in hardness. By analyzing their crystal geometries, band structures and density of states, we elucidate the underlying origins of the related physical properties.

The effect of volume fraction of SiC nanoparticles on the corrosion resistance of the SiCp/Al metal matrix composites (MMCs) in 3.5 wt.% NaCl aqueous solution were investigated by potentiodynamic polarization and electrochemical impedance spectroscopy. The results show that pitting susceptibility is about the same for the nanocomposites and the correspondingly unreinforced matrix metal Al, and the corrosion potentials of the MMCs are about 50 mV-60 mV more positive than that of the unreinforced Al, and is independent of the volume fraction of SiC nanoparticles. The corrosion resistance for the nanocomposite slightly decreases when the volume fraction increases due to both SiC nanoparticle agglomeration and promoting galvanic corrosion between SiC and Al.

A systematic examination of structural phase transitions and mechanical properties for TiO2 under high pressure has been performed by using first-principles calculations. First, we show that the orthorhombic Pca21 structure becomes stabilize at certain pressure and temperature, whereas the cubic fluorite and pyrite structures are not energetically viable in the whole pressure range of 0–200 GPa. These findings support that the experimentally assumed cubic TiO2 should be the Pca21-type TiO2. Secondly, our calculated equations of state for various TiO2 polymorphs are consistent with previous experimental and theoretical results. The only exception is the baddeleyite phase for which we find a significantly lower bulk modulus of 149 GPa than the measured value 290–304 GPa. Finally, our calculations reveal that the recently synthesized Fe2P-type TiO2 exhibits semiconducting features and has the potential to be a superhard material under ultrahigh pressure. It is shown that the high pressure could open a valid avenue for new hard or superhard materials.

Antireflection of silicon surface is one key technology for manufacture of efficient solar cells. The noble metal assisted chemical etching Si wafer can quickly produce a black Si surface with a high porosity in HF-H2O2-H2O solution at room temperature. The pores formed are straight and vertical to the surface of Si. The porous Si surface exhibits a reflectivity of 2 % in the range of 200-1000 nm, which shows that this process is beneficial to improve the conversion efficiency and to decrease the cost of Si solar cells.

We have prepared core/shell structured carbon-encapsulated magnetic nanoparticles (CMNPs) with a simple method by using inorganic iron salt and glucose solution as precursor substance. The synthetic procedure does not require the use of organic solvents. We have utilized X-ray photoelectron spectroscopy, infrared spectroscopy, X-ray diffraction, and Raman analysis to examine the surface properties of CMNPs prepared at different temperature. The specific surface areas, magnetization and contents of graphitized carbon on carbon shell of CMNPs increase with heat treatment temperature. The obtained CMNPs are used to adsorb or preconcentrate bisphenol A (BPA), 4-n-nonylphenol (4-NP), 4-tert-octylphenol (4-OP), diethyl phthalate (DEP), dipropyl phthalate (DPP), dibutyl phthalate (DBP) dicyclohexyl phthalate (DCHP), dioctyl phthalate (DOP), sulfonamide, tetracyclines, and quinolones antibiotics organic compounds from water samples. The adsorption of analytes is mainly based on π-π stacking interaction, hydrophobic interaction and hydrogen bonds between analytes and graphitic carbon. As a result, the adsorption or extraction behaviors of CMNPs to analytes are controlled by the content of oxygen-containing species and graphitized carbon on carbon shell of CMNPs. CMNPs prepared at 200 °C have ample oxygen-containing species (80%) on surface and favor the adsorption and extraction of quinolones antibiotics. CMNPs heated at 300-500 °C with the graphitization efficiency of carbon shell lower than 50% exhibit great preconcentration performance to BPA, 4-NP, 4-OP, DBP, DCHP, DOP, tetracyclines, and quinolones antibiotics. CMNPs prepared at 850 °C are highly graphitized (80%) and have strong adsorption affinity to all model analytes; however, they can quantitatively extract only highly polar sulfonamide antibiotics and moderately polar DEP, DPP because of hard desorption of other model analytes. We suggest that the appropriate adsorbent to certain organic contaminants can be obtained with this technique just by tuning the heat temperature without any post-treatment.

TiO2-coated SnO2 (TCS) hollow spheres, which are new anode materials for lithium ion (Li-ion) batteries, were prepared and characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), cyclic voltammetry (CV), and galvanostatic charge/discharge tests. The results obtained from XRD, SEM, and TEM show that TiO2 can be uniformly coated on the surface of SnO2 hollow spheres with the assistance of anionic surfactant. The cyclic voltammograms indicate that both TiO2 and SnO2 exhibit the activity for Li-ion storage. The charge/discharge tests show that the prepared TCS hollow spheres have a higher reversible coulomb efficiency and a better cycling stability than the uncoated SnO2 hollow spheres.

According to the reservoir condition of the Lamadian block for polymer flooding in Daqing oilfield, the optimized flocculating agent was studied in order to fully use residual polymer in formation and improve oil recovery after polymer flooding. The experimental results showed that stabilized sodium clay is the best flocculating agent and can react with residual polymer to form a floc unit for improved oil recovery (IOR). Using atomic force microscopy, we can see that the flocculating agent can react with residual polymer to form a floc unit and one clay particle usually reacts with four to seven polymer molecules. This residual reutilization technology was applied in six injection wells of Lamadian in Daqing oilfield; the six injection wells had 13 connected production wells with an average water cut of 95.5% and produced polymer concentration of 459 mg/L. About 30,971 m3 flocculating fluid with 842 tons of flocculating agent was injected into the six injection wells. After treatment, the inject...

We demonstrate an inkjet-based microfluidic technique as droplet vaporization deposition (DVD) that can be applied in the incorporation of hydrophobic substrates with microcavities to generate individual polymeric structures. Using soft-lithography method, the SU-8 and polydimethysiloxane were patterned to form various polygon-shaped cavities (side length ~200-700 μm and depth ~ 25-110 μm) which acted as micromolds (templates) for forming the shapes of the droplets deposited. With aqueous polyurethane droplets generated (single volume ~381 pL), the novel various microstructures in polygonal (tri- to hexagonal) forms were created through the deposition and evaporation processes and characterized with exotic performances in optics such as those of microlenses and micromirrors. Experimental and analytical results illustrated that the curved-surface (sinusoidal) topographies of the structures self-formed and detached from the underlying substrates were dominated by capillary action of fluid during evaporation. The merits over the existing techniques such as photolithography includes the one-step, low-temperature (ambient condition, ~1 atm at 25°C), and cost-effective (no waste materials) processes of solid formations. The successful formation of these structures suggests a new mechanism for self-releasing/detaching from the molds. As a reliable technique for the fabrication of such microstructures, the present DVD method presents an alternative method for various applications particularly including optical microelectromechanical system devices and parts used for assembly.

In this work, a new laser Chemical Vapor Pyrolysis (LaCVP) reactor is presented. The concepts behind the new reactor’s design aim to improve and scale up the production of powders compared to conventional used laser CVP systems. For these purposes, the reaction zone has been studied in relation to the nozzle and the laser beam geometry. As a result, a new reaction zone comprising a rectangular nozzle and rectangular laser beam has been developed. The new reactor, including the new reaction zone, has great flexibility towards different type of materials that can be produced. Moreover, the advanced design of the reactor allows flexibility towards the use of various types of equipment, such as, nozzles, hoods, sampling equipment, etc.First encouraging results of silicon synthesis using the new reactor are presented. The silicon nanoparticles were synthesized from silane (SiH4) precursor in a N2 atmosphere. The products have been characterized with TEM, XRD, TGA and FTIR analyses and compared with a commercial available one (Aldrich). The synthesized products show a narrow size distribution and small particle size, in comparison with the commercial material. Future work will include the further development of the system and investigation of the role of the experimental parameters on the product characteristics.

This paper proposed a method of microfabrication for the formation of hemispherical refractive microlenses by depositing a colloid evaporative droplet onto hydrophobic surfaces. The microdroplets made of polyurethane (PU) were self-driven by surface tension to evolve their three-dimensional (3D) shapes on the surface-treated substrate. The substrates were coated with low surface energy material (Teflon) to de-pin the fluids obeying classic Young–Laplace equation until drying. Array and size-variation experiments, corresponding to different placement and droplet volume, were performed for the shaping process in which the polymers of the drops were self-assembled to be hemispherical utilizing general principle of minimal surface energy. Using the hydrophobic surfaces, plano-convex shapes with spherical curvature were fabricated with micrometer dimensions (base radius between 70 and 1016 μm). The formed structures were observed to form themselves hemispherically by the de-wetting (de-pinning) process during most of evaporation. Moreover, the gravity flatting effect was further found for the larger drop (radius = 1016 μm) when compared to that of smaller one (radius = 118 μm). In the cases, both the modeling calculations and experimental results were performed and compared to illustrate the similar geometries with the contact angle (∼70°) using dimensionless analysis. In addition, one interesting and significant finding, based on close morphological inspection of the SEM picture, showed that the resulting elongational polymer chains (width ∼200 nm) stretched (extension ∼5 μm) on the surface nearby the corner of the contact area, indicating a shear stress occurrence. Compared to those previous methods operated on (soft-) photolithographic techniques, this present one could rapidly predict and microfabricate the hemispherical formation in terms of the radius, height, and contact angle. It is also potentially appropriate for smaller and complex placement by using drop-on-demand (DOD) nozzle arrays for mass-production process.

By using the super-resolution near-field structure (super-RENS) method, the super-resolution recording marks are obtained practically by an organic photochromic diarylethene mask layer, under much lower recording laser power of 0.45 mW. The size of recording marks is decreased by 60% (from 1.6 μm to 0.7 μm) for a diarylethene (photo-mode) recording layer by the optical detection method (limited by optical diffraction), or decreased by 97% (from 1600 nm to 50 nm) for a heptaoxyl copper phthalocyanine (thermo-optical) recording layer, the latter is much smaller than the limitation of optical diffraction. In order to obtain a desirable result, a proper extent of photochemistry reaction in the mask layer is needed. Thus, the super-resolution recording marks can be obtained by adjusting the concentration of diarylethene in the mask layer, the recording laser power, and the moving speed of the sample disc.

The fluorescent decays and spectra of pump power density dependent emission demonstrated that the excitation power density was enhanced in Rh640 dye solution containing scattering nanoparticles. Lasing in disordered scattering medium with low threshold, narrow bandwidth, and short duration was observed. The mechanism of this enhancement, together with the lasing properties of low threshold and narrow bandwidth, was discussed.

In the process of light solidification, the solidified distortion of photopolymer resin is a vital control factor for affecting the accuracy of the shape and dimension of parts. This article studies the rule between the distortion and the technology parameters including illumination power, distance and time via experiment. A series of reasonable parameters is determined with the hybrid optimization method of orthogonal experiment, Neural Network and Genetic Algorithm, which can make the solidified distortion of photopolymer resin least and further perfect the traditional solidification experimental model.

Based on analysis on the physical nature of dust precipitation using optimal electric spark rate and some problems relating to dust removing effects, high consumption of electric power and steel material, this article brings forward the query on its sustainable development. Finally this article points out that dust precipitation using direct current supply with extra wide polar distance is the solution to these problems.

In this article, an intelligent optimization analysis method of residual strain for photosensitive resin is put forward based on the finite element analysis. With the methods of orthogonal experiment and radial basis Neural Network, the relationship of the residual strain and solidification technology parameters, such as circumstance temperature, illumination distance and illumination time, is established. A group of reasonable technology parameters is determined by Genetic Algorithm optimization, which can make the residual strain reach its minimum value.

The sound field in the melt processed by 20 kHz ultrasonic to fabricate CNT-AZ91D is investigated by numerical simulation. Firstly, the distribution of sound pressure in the AZ91D melt is calculated by the finite element method after the model of the sound filed of the ultrasonic processing has been built. The simulation results show that a radial sound field forms under the ultrasonic probe, which means that the sound pressure decreases with increasing distance from the sound source. After the sound field is revealed, we study the ultrasonic cavitation in the AZ91D melt with a single-bubbly-change model and examine the bubble change rule under different sound pressures by solving the Rayleigh-Plesset equation. The relationship between sound pressure amplitude and the ultrasonic cavitation in the melt is also discovered. The higher the sound pressure amplitude, the smaller the threshold radius for the bubble collapse is, and thus the ultrasonic cavitation in AZ91 melt happens more easily. Secondly, the sound fields of the melt with different immersed depths of the ultrasonic probe are calculated. The results show the optimal immersed depth is about 30 mm for the same crucible size used in the present study. Furthermore, the corresponding optimal immersed depth can be calculated for different crucible sizes or different melts by the present numerical method, which is important for the practical ultrasonic processing. After analyzing the calculated results for sound field and the cavitation rule of in the AZ91D synthetically, we find that the volume of the effective cavitation zone rapidly increases with the smaller ultrasonic power and then rises almost linearly with the ultrasonic power larger than 500 W. Finally, to verify the simulation method of the sound field, the contrast study between the simulation and experiment of ultrasonic processing using glycerol-water solution is performed. The simulation result of the sound field in glycerol-water solution is similar to that in AZ91D melt. The highest sound pressure occurs near the end face of ultrasonic probe, while the experimental observation shows that the strongest cavitation also happens near the end face of ultrasonic probe, which indicates that the highest sound pressure occurs in the zone.

We report a novel magnetic tweezers for manipulation of a single DNA molecule. The micromachined DNA manipulator can stretch and rotate a single DNA molecule using arrayed microcoils. Key platform technologies including localized DNA immobilization, microcoil fabrication and microfluidics, have been integrated to form the magnetic DNA tweezers. A single DNA molecule is specifically attached onto a magnetic bead and a gold surface and manipulated under a magnetic field generated by built-in hexagonally-aligned microcoils. A highly effective method for the construction of DNA two sticky ends is developed, which is compatible with MEMS technologies. We have successfully demonstrated the rotation of the tethered-bead DNA molecule linked to the gold pattern by circular permutation of the currents applied to the microcoils.

Molybdenum borides are currently raising great expectations for superhard materials, but their crystal structures and mechanical behaviors are still under discussion. Here, we report an unexpected reduction of stability and hardness from porous hP16-MoB3 and hR18-MoB2 to dense hP20-MoB4 and hR21-Mo2B5, respectively. Furthermore, we demonstrate that this anomalous variation has its electronic origin. These findings not only manifest that the long-recognized hP20-MoB4 (hP3-MoB2) and hR21-Mo2B5 should be hP16-MoB3 and hR18-MoB2, respectively, but also challenge the general design principle for ultrahard materials only pursuing the dense transition-metal borides with high boron content.

We report a drastic reduction of hardness of about 61% from WB3 to WB4. The three-dimensional covalent network consisting of boron honeycomb planes interconnected with strong zigzag W-B bonds underlies the high hardness of WB3. Despite the strong intralayer and interstitial B-B bonds, the interlayer B-B nonbonding and the considerably weak zigzag W-B bonding allow the layers of WB4 to cleave readily, which results in the anomalous softening of WB4. The results provide robust evidence that the highest boride of tungsten, which is characterized experimentally by an inexpensive superhard material, should be stoichiometric WB3, not WB4.

The small -angle X-ray scattering method was used to study the properties of nanocrystals produced from annealing the newly developed high-strength, high-toughness amorphous alloy Al88Ce2Ni9Fe1. The distribution of the nanocrystal size and the changes in specific internal surface were studied in a series of experiments. Information on the gyration radius , Porod radius, integration invariance, distribution of nanocrystal size, crystallity and the changes in specific internal surface are obtained.

A new methodbackground correction of SAXS intensities scattered by theaged metallic glass is proposed.The inte nsities scattered by the as-quenched samplewere taken as the bacground scattering.This motliod was applied to the backgroundcorrection of the SAXS intensities scattered by Cu￣(73)Sn_6Ni_6P_(15) metallic glass aged at473 K for 4hs. Porod constant K′_p=4.6 × 10￣(-2)(nm￣(-3))￣Ω_s=1.63(nm￣(-2)),specificinner surface S_p=84m￣2/cm￣3, and Porod's radius of the crystalline particle R_p=4.4nm were obtained by using this method of backgroud correction.

This article proposes a new type of electrode for micro-electro-discharge machining (micro-EDM), which can produce ultra fine micro components from various kinds of materials including those that cannot be processed by the silicon or the Lithographie Galvanoformung Abformung (LIGA) processings. This electrode is made by way of the electrodeposition process on the basis of the difference between the discharging performance of the electrodeposited coating and that of the matrix to ensure uniform wear of electrode bottom faces. With this electrode, micro-holes on ANK80 steel can be successfully manufactured in a short period of time. Compared to the traditional electrodes, Cu-ZrB 2 composite coating electrodes display better wear resistance on the same experimental conditions. The results disclose the prospects for this electrode to be used in producing micro components of high-aspect-ratio and 3D micro-cavities.

In this paper, the crystallization of the amorphous Ni83Cr7Fe3Si4B3 alloy was investigated and its "T-T-T" diagrams under 1 bar and 100 kbar were obtained. The results indicate that the crystallization temperature decreases and the metastable II phase does not form if the amorphous state is subjected to high pressure annealing. In addition, the activation energy of crystallization under 1 bar and 100 kbar was calculated respectively.