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The structural characteristics of litchi shell-derived carbon are conducive to regulation and modification. Using biomass waste litchi shells as carbon source and nano-silicon particles to prepare silicon-carbon composite materials to relieve the volume effect of silicon in the charge and discharge process, litchi shell-derived activated carbon (LAC) with high specific surface area (1011.115 m2 g−1) and high porosity was obtained from litchi shell as silicon buffer matrix by simple high-temperature calcination and activation of ZnCl2. A silicon-carbon composite material (3D LAC@Si) with an embedded cladding structure was prepared with a high-energy ball milling process. In the electrochemical performance test, 3D LAC@Si as the negative electrode of a lithium-ion battery showed a high lithium storage capacity of 834.4 mAh g−1 and a high coulombic efficiency of 98.34% after cycling 100 cycles at a current density of 0.2A g−1.

Microwave-synthesized SiO2-reinforced B-N-co-doped reduced graphene oxide (SiO2-B-N-GO) nanocomposites were characterized by X-ray photon spectroscopy (XPS), X-ray diffraction (XRD), infrared (IR) spectroscopy, and transmission electron microscopy/energy dispersive X-ray (TEM/EDX) analysis. The tribological properties of the SiO2-B-N-GO prepared as anti-wear additives for enhanced lubrication were studied using a four-ball tester. The experiment results indicated that SiO2-B-N-GO exhibits excellent load-carrying, anti-wear, and anti-friction properties in a base oil, especially at the optimal concentration of additives at 0.15 wt%. The wear scar diameter decreased from 0.70 to 0.37 mm and the coefficient of friction was reduced from 0.092 to 0.070, which reductions are attributed to the formation of B-N and graphene layer tribofilms of several tens of nanometers in thickness that prevented direct contact between metals.

Toxicity and environmental issues have elicited research attention regarding the need to prepare a green flame retardant with high flame retardancy. Here, a supermolecular self-assembly technology was used to prepare nickel phytate as shell materials aggregated on aminated silica nanotemplates through electrostatic interactions as a green novel flame retardant (Ni@SiO2-PA). After incorporating the obtained core–shell structured Ni@SiO2-PA into epoxy resin (EP), the supermolecular shell effectively enhanced the adhesive property between the nanoparticles and the EP matrix. The thermal stability was improved, and the peak heat release rate decreased significantly after introducing the well-characterized Ni@SiO2-PA. The absorbance intensity of the toxic aromatic compounds also decreased. Moreover, the char yield of the EP composites was improved because of the synergetic coupled effects between the nickel phytate supermolecules and SiO2 nanotemplates. The possible fire-retardancy mechanism was hypothesized as follows. The crosslinking structure of the silica initially enabled the formation of a polymer network to prevent further decomposition. The N–P synergistic flame-retardancy system then generated a gas barrier and P-rich intumescent char. Besides, char-residue generation was catalyzed by introducing Ni2+, which isolated the heat and the exchange between oxygen and the matrix. Overall, this study proposes a novel green flame retardant that may enable significant improvements in preparing environmentally friendly organic–inorganic materials with applications in the fields of flame-retardant composites.

Adsorption behavior of thiadiazole derivatives, 2,5-bis(ethyldisulfanyl)-1,3,4-thiadiazole (DTA), dimercapto-1,3,4-thiadiazole (DMDT) as anticorrosion additives at copper oxide surface were studied by first-principles calculations, weight loss, electrochemical and surface characterization techniques. The adsorption energies calculated by density functional theory (DFT) were less than 0.3 eV, DTA and DMDT physically adsorbed on the copper surface and cannot replace the oxygen atom at the top site of the Cu O slab models. The predicted physically interaction of the corrosion inhibitor on the copper surface, which was basically consistent with the results of XPS analysis and surface microtopography. It was shown that in the presence of DTA and DMDT adsorbed on copper surface depress the reaction rate of anodic dissolution and cathodic hydrogen evolution and obey Langmuir isotherm. Surface findings indicated the inhibitor film formed at copper surface can block corrosion and improve hydrophobicity.

For the development of national industry green environmental protection, the use of zinc dialkyl dithiophosphate (ZDDP) should be reduced in the process of mechanical lubrication, two novel borate ...

In this paper, a silicon optical waveguide with high light coupling efficiency and large misalignment tolerance between the silicon waveguide and the laser diode is presented. The silicon optical passive device is designed as a multi-branch structure based upon the silicon on insulator (SOI) platform, which is like a power splitter used in turn. The laser diode is mounted at the end of the multi-branch SOI waveguide structure by flip-chip bonding process. Theoretically, by optimizing the silicon waveguide structure, more than 52% light power of the semiconductor laser diode is coupled into the multi-branch waveguide and a mismatch of 20 μ m in a specific direction only leads to a decrease of 5% in the coupling efficiency. Experimentally, a 37.5% coupling efficiency is obtained from an integrated unit consisting of a single mode laser and the multi-branch waveguide by using a normal precision flip-chip bonder. The special multi-branch waveguide structure is reported for the first time.

Damage identification based on the change of dynamic properties is an issue worthy of attention in structure safety assessment, nevertheless, only a small number of discontinuous members in existing structure are damaged under service condition, and the most remaining members are in good condition. According to this feather, we developed an effective damage location and situation assessment algorithm based on residual mode vector with the first mode information of targeted structure, which utilized the quantitative relationship between first natural modes of global structure with the change of the element stiffness. Firstly, the element damage location is determined with exploitation of the sparseness of element stiffness matrices based on the discontinuity of damaged members. Then, according to the distribution characteristics of the corresponding residual mode vector, the nodal equilibrium equation about the damage parameter is established based on the residual mode vector, and the damage coefficients of structural elements are evaluated with the proposed equations. Two numerical examples are given to verify the proposed algorithm. The results showed that the proposed damage identification method is consistent with the preset damage. It can even accurately identify large-degree damages. The proposed algorithm only required the first-order modal information of the target structures and held few requirements of analysis resource; hence when compared with existing methods, it has obvious advantages for structural damage identification.

We demonstrate an optimized structure design and analyze the optical mode characteristics of 1.55 µm Si-based III-V square microcavity laser with InAs/InGaAs quantum-dot active region and directional midpoint output waveguide. © 2020 The Author(s)

A liquid-liquid extraction of nitrobenzene (NB) in impinging stream-rotating packed bed (IS-RPB) was proposed using cyclohexane as an extractant, presented for its improvement of micromixing and mass transfer performance. The effects of pH, phase ratio (the flow rate of organic phase/aqueous phase) and rotating speed of IS-RPB on removal efficiency and extraction stage efficiency of NB were investigated experimentally in IS-RPB. The experimental result showed that the removal rate of NB reached 94.93%, and extraction stage efficiency was 99.99% in IS-RPB, respectively, under the following experimental conditions including: a pH of 6.4, a temperature of 25 °C, a phase ratio of 1:1, a liquid flow rate of 50 L/h, a rotating speed for IS-RPB of 400 r/min, and an initial impinging velocity of 7.88 m/s. Besides, IS, RPB and IS-RPB were compared based on the removal rate of NB and extraction stage efficiency in the same experimental conditions. Compared with other mixing devices, IS-RPB has better extraction stage efficiency and shorter extraction time than other extraction devices, proving that high gravity technology can be utilized to effectively improve the extraction stage efficiency and has a good application prospect.

The metal-organic frameworks (MOFs) MIL-100(Fe) and graphene oxide (GO) composites were prepared by hydrothermal method and characterized by X-ray diffraction (XRD), nitrogen adsorption/desorption, thermal-gravimetric (TG) analysis, the Fourier Transform Infrared Spectroscopy (FTIR), and scanning electron microscopy (SEM). The composites were used for the adsorption of methylene blue (MB) and methyl orange (MO) in aqueous solution. The results indicated that MIL-100(Fe) and GO formed a sandwich-like structure, and the crystal structure of MIL-100(Fe) was reserved in the composites. The attachment of GO layers to the MIL-100(Fe) decreased the surface area from 1690 to 1602 m2/g, and pore volume from 0.996 to 0.770 cm3/g when 5% (w/w) GO was added, due to the coating of MIL-100(Fe) by GO sheets. The addition of 5% (w/w) GO increased the adsorption capacity for MB (from 1019 to 1231 mg/g) and MO (from 667 to 1189 mg/g). The composites showed a better thermal stability than MIL-100(Fe); the decomposition temperature increased from 280 to 350 °C. The addition of GO improved the properties of MIL-100(Fe) as an adsorbent for MO/MB from aqueous solution.

The emulsified behaviors in the process of preparing methanol-diesel emulsified fuel are investigated by the application of an impinging stream-rotating packed bed (IS-RPB). The emulsified processes are composed of the combinations of initial emulsification of impinging stream process, intensified emulsification of IS-RPB and perfect emulsification of back-splashing and atomization to complete the entire emulsified process through the analysis of force posed on all fluid particles in IS-RPB. The existence of the three emulsified processes is proved using the computational fluid dynamics (CFD) simulations. The turbulent kinetic energy and velocity vector of the three emulsified processes using the CFD simulations were analyzed logically, which proved the existence of the three emulsified processes. Based on the analysis and CFD simulations, the properties of stabilization, dispersion, micro-mixing and power consumption performance were compared under the IS-RPB and high speed stirrer, which further prove the practicability and advancement of this technology for methanol-diesel emulsified fuel.

The threading dislocations (TDs) in GaAs/Si epitaxial layers due to the lattice mismatch seriously degrade the performance of the lasers grown on silicon. The insertion of InAs quantum dots (QDs) acting as dislocation filters is a pretty good alternative to solving this problem. In this paper, a finite element method (FEM) is proposed to calculate the critical condition for InAs/GaAs QDs bending TDs into interfacial misfit dislocations (MDs). Making a comparison of elastic strain energy between the two isolated systems, a reasonable result is obtained. The effect of the cap layer thickness and the base width of QDs on TD bending are studied, and the results show that the bending area ratio of single QD (the bending area divided by the area of the QD base) is evidently affected by the two factors. Moreover, we present a method to evaluate the bending capability of single-layer QDs and multi-layer QDs. For the QD with 24-nm base width and 5-nm cap layer thickness, taking the QD density of 1011 cm−2 into account, the bending area ratio of single-layer QDs (the area of bending TD divided by the area of QD layer) is about 38.71%. With inserting five-layer InAs QDs, the TD density decreases by 91.35%. The results offer the guidelines for designing the QD dislocation filters and provide an important step towards realizing the photonic integration circuits on silicon.

Natural organic acids can reduce Cr(VI) to Cr(III) in soil and aquatic environments, but that reductive reaction is too slow for practical application in a Cr(VI) removal process. In this study, we prepared ceramsite particles (CPs) and used them in a citric acid-based Cr(VI) reduction process to analyze their catalytic functions and find their optimal reduction conditions under increasing pH and with and without light. CPs increased the apparent reduction rate constants from 16.35 at pH = 2.6 to 44.85 mg L−1 d−1, and increasing pH decreased the CPs’ catalytic effect. Light positively influenced the reduction rate, which more than doubled under illumination compared to the rate in the dark. We identified soluble Fe(III), that had dissolved from CPs in the reaction solution, as the catalyst for Cr(VI) reduction by citric acid. Under light, soluble Fe(III) complexed with citric acid, and those initiated complexes yielded Fe(II)-citrate and reductive organic radicals that promote Cr(VI) reduction. In the dark, Fe(III)-citrate combined with Cr(VI) to form ring complexes that were responsible for rapid Cr(VI) reduction. Our results reveal how CPs containing soluble Fe(III) can efficiently promote Cr(VI) reduction by organic matter in an aqueous solution.

A novel process based on an impinging stream-rotating packed bed (IS-RPB) was proposed for preparing nanoscale zero-valent iron (NZVI) and degrading nitrobenzene (NB) simultaneously. The obtained NZVI particles were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy experiments (HRTEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The experimental results showed that the NB removal efficiency increased with the augment of liquid flow rate and initial reactant concentrations. The NZVI prepared with Fe2+ as an iron source had high reactive activity and its removal efficiency of NB could be maintained at a high level in acidic or a weakly basic condition (pH

Electrode material is a key component in microbial fuel cells (MFCs), and exploring cost-effective electrode materials will greatly help with MFC development, especially the scaling up. In this study, a commercially available material – nickel-coated carbon fiber (Ni-CF) has been investigated as an alternative cathode electrode material to carbon cloth (CC). Both three-electrode cell and MFC tests are carried to examine electrochemical performance and actual electricity generation of the prepared cathode electrodes. It is found that Ni-CF exhibited higher current generation in linear sweep voltammetry (LSV) and lower resistance in electrochemical impedance spectroscopy (EIS) tests than those of CC and CF. When being coated with AC, Ni-CF has the highest actual loading amount among the tested materials. As a result, AC/Ni-CF leads to lower charge transfer resistance (95.1 Ω) and higher current density (8.07 mA m−2) than AC/CC (115.3 Ω and 3.40 mA m−2). In the MFC test, the cathode using AC/Ni-CF results in the maximum power density of 6.50 W m−3, higher than AC/CC at 4.29 W m−3. This high power output gives cost efficiency of AC/Ni-CF at 299.0 mW $−1, nearly twice that of AC/CC (151.7 mW $−1). The initial AC coating amount of 4 g is found to be the optimal amount to achieve optimally actual AC loading amount on the cathode electrode with balanced catalytic ability and (possible) oxygen transfer. Those results encourage further investigation of Ni-CF for MFC applications towards improved performance and cost efficiency.

Bioelectrochemical system (BES) is promising technology to simultaneously treat wastewater and recover energy, and electrode material is important for the system performance. Microbial fuel cell (MFC) is one of typical BES to be applied in wastewater treatment. How to improve the electrode material is significant to improve wastewater treatment, energy recovery and cost effectiveness. In this study, 3D-weaved carbon electrode entity, assembled by multiple pieces of carbon mesh (CM), was proposed to combine all electrode components as entity to facilitate electron conduction and ionic migration, compared with carbon brush (CB) and granular activated carbon (GAC). The result showed that current density and internal resistance of MFC using 3D-weaved CM as horizontally extended inside anode (CM(T)) were 30.9 A m-3 and 4.5 Ω, respectively, with higher output than traditional GAC (22.6 A m-3 and 6.2 Ω). Though GAC had greater electrode filling and surface area for biomass growth, the electron transfer efficiency per unit electrode biomass was only at 0.0019 ± 0.0002 mol g-1 d-1, much lower than CM(T) at 0.0077 ± 0.0009 mol g-1 day-1. Higher ionic migration rate of CM(T) suggested the assisting effect of composite electrode to enhance ionic transportation towards the cathode. Microbial analysis further indicated that 3D-CM electrode network could simultaneously enhance Geobacter abundance and methanogen activity, suggesting the importance of electrode network on electricigens. Furthermore, CM(T) could obtain 10 times higher energy output efficiency than traditional GAC when applied inside anode chamber. This study proved that network construction of anode electrode could promote the electrode performance and cost effectiveness, suggesting the future development of reactor design of bioelectrochemical system.

A new family of hybridized local and charge-transfer (HLCT) emitters bearing a pyrene structural unit has been developed. Deep-blue OLEDs based on them achieved high brightness over 10 000 cd m−2, high maximum external quantum efficiency over 10.5%, and high maximum exciton utilization efficiency approaching 100%, with CIE coordinates of (0.152, 0.065).

We optimize the structure of a silicon-based InAs/InGaAs quantum dot square microcavity laser with an output waveguide structure. By designing a new laser structure, the emission wavelength is extended to 1550 nm. We investigate the structure parameters that affect the quality factor and optical mode of the square microcavity, including the side length of the microcavity, the width of the output waveguide, the cladding layer thickness and the etching depth. By connecting the output waveguide at the edge-midpoint of the square microcavity, both the unidirectional emission and mode selectivity can be obtained, which avoids mode competition. The 1550 nm wavelength single-mode laser is beneficial and has reat significance for the development of silicon-based optoelectronic integration.

Efficient oil–water separation plays a vital role in treating large amounts of industrial wastewater. However, current traditional separation methods are entwined with problems such as low efficiency and poor operability. Herein, we reported a nanofiber based on electrospinning and electrospray technology and spraying microspheres on the surface of a fiber mat for efficient oil–water separation. Owing to the electrostatic repulsion among the microspheres, the surface of the developed membrane had a honeycomb-like through-hole structure and super-high oil–water separation efficiency and oil flux. After 10 cycles, the membrane showed good separation efficiency and flux. This innovative work may provide a new idea and method for the design of biomimetic biopolymers, with broad application prospects in the field of oil–water separation.

We investigate the thermal stresses for GaAs layers grown on V-groove patterned Si substrates by the finite-element method. The results show that the thermal stress distribution near the interface in a patterned substrate is nonuniform, which is far different from that in a planar substrate. Comparing with the planar substrate, the thermal stress is significantly reduced for the GaAs layer on the patterned substrate. The effects of the width of the V-groove, the thickness, and the width of the SiO2 mask on the thermal stress are studied. It is found that the SiO2 mask and V-groove play a crucial role in the stress of the GaAs layer on Si substrate. The results indicate that when the width of V-groove is 50 nm, the width and the thickness of the SiO2 mask are both 100 nm, the GaAs layer is subjected to the minimum stress. Furthermore, Comparing with the planar substrate, the average stress of the GaAs epitaxial layer in the growth window region of the patterned substrate is reduced by 90%. These findings are useful in the optimal designing of growing high-quality GaAs films on patterned Si substrates.

Fabrication and characteristics of 2004-nm wavelength InP-based ridge-waveguide distributed feedback lasers with InGaAs multi-quantum wells are described. By means of a relatively simple fabrication process, the device can operate stably in a single mode without any mode hopping. A high side-mode suppression ratio of 49 dB is achieved. The emission wavelength can be finely controlled from 2000 to 2008 nm with a current-tuning rate of 0.0047 nm/mA and a temperature-tuning rate of 0.127 nm/K. In addition, the influence of facet coating conditions on the single-mode property of these distributed feedback lasers was investigated.

We report on ultra-short pulse single-section mode-locked lasers emitting at 1.55 μm, based on self-assembled InAs/InGaAsP/InP quantum dot active regions grown by metal-organic vapor phase epitaxy (MOVPE). For a 1.5-mm-long Fabry-Perot laser, mode-locking at a repetition rate of 29.8 GHz with pulse duration of 855 fs is obtained without any external pulse compression techniques. The mode-beating exhibits a narrow RF linewidth less than 30 kHz, and a wide frequency tuning range up to 73 MHz can be achieved by simply changing the injection current. Moreover, a higher repetition rate of 55.6 GHz and the transform limited Gaussian-pulse with the 707 fs pulse duration are achieved from a device with a shorter cavity length of 0.8 mm.

We demonstrate an ultrashort pulse and high power single-section mode-locked laser using chirped multiple InAs/InP quantum dot (QD) layers as the active region of the laser. The chirped QD active region consists of seven layers of InAs QDs of different heights, which is beneficial in broadening the material gain spectrum. A transform-limited Gaussian pulse with a pulse duration of 322 fs is obtained from a device of 1 mm in length. Moreover, the femtosecond pulse with highest peak power of 6.8 W is achieved for the 45.5-GHz mode-locked laser. These results show the potential of the mode-locked laser for femtosecond pulse generation with high peak power and high repetition rate in the 1.55- $\mu \text{m}$ wavelength band.

InAs/InAsSb superlattices were grown on (0 0 1) GaSb substrates by metal organic chemical vapor deposition for potential applications as mid-infrared optoelectronic devices. X-ray diffraction, transmission electron microscopy, photoluminescence emission and spectral photoconductivity were used to characterize the grown structures. Generally, photoluminescence emission measurements of InAs/InAsSb superlattices were performed over the temperature range from 11 K to 300 K. The Varshni and Bose–Einstein parameters were determined. Low-temperature photoluminescence measurements showed peaks at 3–5 μm, while photoconductance results showed strong spectral response up to room temperature, when the photoresponse onset was extended to 5.5 μm. The photoluminescence emission band covers the CO 2 absorption peak making it suitable for application in CO 2 detection.

Boron doping brings remarkable features and modified properties to graphene. In this study, we used molecular dynamics simulations to investigate the influence of vacancies on the graphene boron doping process. The existence of vacancies increases the boron content of doped graphene sheet. The physical mechanisms behind this phenomenon are discussed. The vacancy concentration of graphene affects the formation energy of boron-vacancy pair, the collision frequency between boron atoms and graphene sheet and also affects the boron atom capture cross section of graphene. We have also investigated the boron doping process for bicrystalline graphene. The results reveal that boron atoms tend to be adsorbed on the grain boundary region. The mechanical properties of the boron doped bicrystalline graphene are enhanced compared with the undoped graphene.

InAs/InAsSb superlattices were grown on (001) GaSb substrates by metal organic chemical vapor deposition for potential applications as mid-infrared optoelectronic devices. Atomic force microscopy, X-ray diffraction, transmission electron microscopy and photoluminescence emission were used to characterize the grown structures. The photoluminescence emissions from InAs/InAsSb superlattices were performed over the temperature range from 11 K to 300 K. The Varshni and Bose-Einstein parameters determined for energy gap were extracted from the photoluminescence spectra by the fitting procedures. The mid-infrared InAs/InAsSb superlattices showed a temperature change of 0.32 meV/K. The value is smaller than that of HgCdTe and InSb, making them more desirable for high operating temperature infrared devices.

We describe the controlled growth of planar InAsSb nanowires (NWs) on differently oriented Si substrates without any foreign catalysts. Interestingly, the planar InAsSb NWs grew along four criss-crossed ⟨110⟩ directions on an [100]-oriented substrate, two ⟨100⟩ directions plus four ⟨111⟩ directions on an [110]-oriented substrate, and six equivalent ⟨112⟩ directions on an [111]-oriented substrate, which correspond to the projections of ⟨111⟩ family crystal directions on the substrate planes. High-resolution transmission electron microscopy (HRTEM) reveals that the NWs experienced a transition from out-of-plane to in-plane growth at the early growth stage but still occurred on the {111} plane, which has the lowest surface energy among all the surfaces. Furthermore, the NWs exhibit a pure zinc-blende crystal structure without any defects. A growth model is presented to explain growth of the NWs. In addition, conductive atomic force microscopy shows that electrically rectifying p-n junctions form naturally between the planar InAsSb NWs and the p-type Si substrates. The results presented here could open up a new route way to fabricate highly integrated III-V nanodevices.

In this work, a new type of emitting direction tunable slotted laser array for Lidar applications is proposed. By designing the structure of periodic slots, the laser array can achieve tunable emitting direction in a wide range with low vertical divergence angle. The laser array can be directly used as Lidar emitting chip without complex beam reshaping, coupling or mechanically moving parts, which makes it has the advantages of good stability, system simplification and low cost compared with other Lidars. Experimentally, an 11-channel laser array of C band with periodic slots at the output end is fabricated based on AlGaInAs/InP material system. As the slot period changes from 8 μ m to 18 μ m , the inclined angles of emission from 66.6° to 20.25° with all the vertical divergence angles less than 3.5° are obtained, and the minimum vertical divergence angle is even 1.3°. Typical optical power is 13.5 mW under 600 mA continuous injection.

This study introduced a novel dual-anode assembled microbial desalination cell to enhance the performance of domestic wastewater treatment. Two parallel units were fabricated with two anodes and one cathode, which is separated by two ion exchange membrane stacks. A hollow fiber membrane module was inserted in the cathode to intercept suspended solids and microbes. Based on preliminary experiments where synthetic wastewater was utilized, anode hydraulic retention time of 10 h and cathode aeration rate of 0.16 m3/h were chosen as the operating conditions. By innovatively connecting four membrane stacks in cascades, which multiplied flow rate without adding extra circulation pumps, the desalination rate of the system was improved 214.8% compared with single membrane stack mode. When modified domestic wastewater was applied, the average removal efficiencies of chemical oxygen demand, ammonia nitrogen, total nitrogen and total phosphorous reached 96.9%, 99.0%, 98.0% and 98.3%, respectively.

We present a study of Au-free InAsSb nanowire (NW) growth on Si (111) substrate under different growth parameters including V/III ratio, group Sb flow rate fraction (Sb-FRF, TMSb/(TMSb+AsH3)), and temperature. It was found that two different kinds of growth mechanisms for the Au-free InAsSb NW growth may be dominant depending on the growth parameters. At low V/III ratio and relatively high Sb-FRF, the NWs grow via vapor–liquid–solid (VLS) mode, while at high V/III ratio and relatively low Sb-FRF, they grow via vapor–solid (VS) mode. The NWs obtained by the two growth modes show clear differences in morphology, growth direction, and crystal quality. Under VS mode, the NWs exhibit unified growth direction and a uniform composition distribution, which are beneficial to integration devices of multiple NWs. On the other hand, under VLS mode, the NWs are first reported with pure crystal phase, which will be useful for the development of single NW devices.

Three red-emissive D–π–A-structured fluorophores with an aromatic amine as the donor, ethene-1,2-diyl as the π-bridge, and 1,8-naphthalimide as the acceptor subunit, namely, (E)-6-(4-(dimethylamino)styryl)-2-hexyl-1H-benzo[de]isoquinoline-1,3(2H)-dione (Nap1), (E)-2-(2,6-di(isopropyl)phenyl)-6-(4-(dimethylamino)styryl)-1H-benzo[de]isoquinoline-1,3(2H)-dione (Nap2) and (E)-2-(2,6-di(isopropyl)phenyl)-6-(2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-9-yl)vinyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione (Nap3), were designed and synthesized. In-depth investigations on the correlations between their molecular structures and photophysical characteristics revealed that the presence of an electron-rich 4-dimethylaminophenyl donor moiety in compound Nap1 could endow it with a red emission (e.g., λPLmax = 641 nm in the host–guest blend film with a 14 wt% guest composition); moreover, the replacement of the n-hexyl group of Nap1 bonding to the imide nitrogen atom for a more bulky 2,6-di(isopropyl)phenyl one would result in compound Nap2 with more alleviated concentration quenching. Alteration of the 4-(dimethylamino)phenyl donor subunit of Nap2 into a more electron-donating 1,1,7,7-tetramethyljulolidin-9-yl substituent would render compound Nap3 with more improved chromaticity (e.g., λPLmax = 663 nm in a 14 wt% guest-doped film). Consequently, Nap3 could not only emit standard-red fluorescence with satisfactory chromaticity, but it also showed suppressed intermolecular interactions. Using Nap3 as the dopant, a heavily doped standard-red organic light-emitting diode (OLED) with the device configuration of ITO/MoO3 (1 nm)/TcTa (40 nm)/CzPhONI:Nap3 (14 wt%) (20 nm)/TPBI (45 nm)/LiF (1 nm)/Al (80 nm) was fabricated, and the Commission Internationale de L’Eclairage coordinates, maximum external quantum efficiency and maximum current efficiency of this OLED were (0.67,0.32), 1.8% and 0.7 cd A−1, respectively. All these preliminary results indicated that 1,8-naphthalimide derivatives could act as quite promising standard-red light-emitting materials for OLED applications.

We have determined the band overlap in type II InAs/GaSb superlattice (SL) structure based on the temperature dependent photoluminescence (PL) results of a short wavelength SL sample. The band overlap value is treated as a temperature variable and is simulated by fitting the PL peak position using the 8K·P method. It is found that the band overlap monotonically decreases from 0.325 to 0.225 eV when temperature is increased from 12 to 90 K. The calculated e1–hh1 transition using the obtained band overlap data shows an agreement with the PL results of another SL sample.

We demonstrate electrically pumped continuous-wave (CW) lasing near 1.5 pm at room temperature in microcylinder lasers with InAs quantum dot active regions. The microcylinder radius can reduce to 4μm at room temperature and contentious-wave lasing.

Nanoscale zero-valent iron (nZVI) was continuously prepared by high-gravity reaction precipitation through a novel impinging stream-rotating packed bed (IS-RPB). Reactant solutions of FeSO4 and NaBH4 were conducted into the IS-RPB with flow rates of 60 L/h and rotating speed of 1000 r/min for the preparation of nZVI. As-prepared nZVI obtained by IS-RPB were quasi-spherical morphology and almost uniformly distributed with a particle size of 10–20 nm. The reactivity of nZVI was estimated by the degradation of 100 ml nitrobenzene (NB) with initial concentration of 250 mg/L. The optimum dosage of nZVI obtained by IS-RPB was 4.0 g/L as the NB could be completely removed within 10 min, which reduced 20% compared with nZVI obtained by stirred tank reactor (STR). The reduction of NB and production of aniline (AN) followed pseudo-first-order kinetics, and the pseudo-first-order rate constants were 0.0147 and 0.0034 s−1, respectively. Furthermore, the as-prepared nZVI using IS-RPB reactor in this work can be used within a relatively wide range pH of 1–9.

We present a study on the growth of InAs1−xSbx alloy nanowires directly on Si (111) substrates via a self-seeded mechanism for the first time. Through varying group V flow rate ratios, InAs1−xSbx nanowires with x=from 0 to 0.43 are obtained. It is found that Sb content has a significant effect on the morphology and crystal quality of the formed InAs1−xSbx nanowires. Furthermore, the axial and radial growth rates of the nanowires change in opposite trends with increasing group V flow rate ratio. This indicates that the growth rate of InAs1−xSbx nanowires is ultimately determined by Sb compositions of the nanowires. In addition, the scanning electron microscopy and transmission electron microscopy measurements reveal that the dimensional uniformity and crystal quality of InAsSb nanowires with a small amount of Sb compositions are greatly improved compared to the reference InAs nanowires. The effect mechanism of Sb on the growth of InAs1−xSbx nanowires is clarified, which will be a guide for making high-quality InAs1−xSbx nanowires and relevant heterostructure devices in the future.

The thickness influence of thermal oxide layers on Si(111) substrates on the formation of self-catalyzed InAs nanowires (NWs) grown by metal-organic chemical vapor deposition (MOCVD) has been investigated. It is found that the thickness of the thermal oxide layer has a strong effect on the morphological characteristics of InAs NWs formed on the Si substrates. In particular, within a suitable thickness range, it is possible to achieve vertical InAs NWs with a uniform distribution of their positions, lengths and diameters. In addition, growth on the thermal oxide layer both improves the morphology of the NWs, and suppresses the frequently observed parasitic islands compared to growth on bare Si. A growth model, which is based on the diffusion length of adatoms, the growth temperature, the thickness of thermal oxide layer, the size and the density of thermal oxide holes, has been developed to explain the formation of the self-catalyzed InAs NWs on the Si substrate with a thermal oxide layer.

Analysis of the dynamic strain aging (DSA) effect was carried out for a reactor pressure vessel (RPV) steel, the A508-class3. The aging process includes the application of various plastic strain values of 1%, 2%, 4%, 6% and 8% with different strain rates at certain tempering temperatures. The microstructure of the specimens was analyzed in detail using optical microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate that serrated stress–strain curves occurred at the DSA process, and the new hardening phase of M23C6 type carbide is precipitated to pin the mobile dislocations. The hardening effect increases with the increase of the strain value within the uniform plastic strain region, even though the softening effect caused by dynamic recovery is obvious. After analyzing the correlations between aging parameters, hardening, ductile-brittle transition temperature and irradiation effect, it is found that the degeneration of mechanical properties caused by DSA is similar to the irradiation effect.

Detailed investigation was carried out on the tool joint failure of the internal & external upset (IEU) GSS105 drill pipes. Stresses were analyzed using 2D finite element method (FEM) for the threaded tool joint of the drill pipe under the combined loading conditions containing preload, tensile and bending loads. The stress concentration factors in the pin and box were calculated. Results showed that the maximum stress concentration occurred at the roots of the first tooth from the pin tool joint shoulder of the drill pipe. Fractographic observation revealed that the tool joint failure of the drill pipe was caused by fatigue crack nucleated at the tooth root and propagated through the wall of the tool joint. The deterioration of the fatigue resistance of the tool joint is related to dogleg region where severe cyclic bending load exists due to the local deviation of the drill pipe from the vertical line.

The correction ability of deformable mirrors (DMs) with different fatigued degrees has been studied by quantitatively analyzing the fitting wavefront, the times-diffraction-limit factor β, and the wavefront power spectral density (PSD). The results indicate that the fatigue of DMs can be ignored when the DM continually works below 105 cycles, while the performance of the DM degrades gradually if the loading cycles of the DMs exceed 105. Consequently, the peak-valley (PV) value of the fitting wavefront of the DM decreases with the increase of the fatigue degree of the DM, resulting in the increase of the PV value of the corresponding residual wavefront. Meanwhile, the larger PV value of the distorted wavefront or the higher proportion of the high-spatial-frequency components gives rise to the larger residual wavefront after the existence of the fatigue of the PZT actuators, the worse corrected beam quality, and the lower correction ability of the DM. The correction ability of the DM composed of different piezoelectric ceramics has also been evaluated by the β factor of the corrected laser beam, which indicates that for the given loading cycle, the fatigue degree and the correcting ability of the DM composed of different piezoelectric ceramics are different.

The impact of a double-cap procedure using two growth temperatures on the optical characteristics of InAs/InGaAsP/InP quantum dots (QDs) grown by metal-organic chemical vapor deposition has been investigated. With a combination of optimized thickness of the first cap layer and elevated growth temperature for the second cap layer, it is found that the photoluminescence (PL) linewidth of QDs can be significantly reduced from 124 meV to 87 meV at room temperature (RT). This reduction in PL linewidth is likely to be due to the enhanced As/P exchange reaction and indium migration at high growth temperature, which lead to a more uniform QD height distribution. Moreover, the uniformity of the PL peak intensity and peak energy on the wafer surface is evidently improved due to the higher material quality achieved when an elevated temperature is used for the SCL growth.

We demonstrate an ultrashort pulse and high power single-section mode-locked laser using chirped multiple InAs /InP quantum dot (QD) layers as the active region of the laser. The chirped QD active region consists of seven layers of InAs QDs of different heights, which is beneficial in broadening the material gain spectrum. A transform-limited Gaussian pulse with pulse duration of 322 fs is obtained from a device of 1 mm in length. Moreover, the femtosecond pulses with peak power of as high as 6.8 W are achieved for the 45.5 GHz mode-locked laser. These results show the potential of the mode-locked laser for femtosecond pulse generation with high peak power and high repetition rate in the 1.55 µm wavelength band.

We report the growth of InAs/GaSb core-shell heterostructure nanowires with smooth sidewalls on Si substrates using metal-organic chemical vapor deposition with no assistance from foreign catalysts. Sb adatoms were observed to strongly influence the morphology of the GaSb shell. In particular, Ga droplets form on the nanowire tips when a relatively low TMSb flow rate is used, whereas the droplets are missing and the radial growth of the GaSb is enhanced due to a reduction in the diffusion length of the Ga adatoms when the TMSb flow rate is increased. Moreover, transmission electron microscopy measurements revealed that the GaSb shell coherently grew on the InAs core. The results obtained here show that the InAs/GaSb core-shell nanowires grown using the Si platform have strong potential in the fabrication of future nanometer-scale devices and in the study of fundamental quantum physics.

Most glass composites products in engineering are manufactured by a pultrusion process. Because the pultrusion process is affected by many factors, it is not easy to control the performance of products. In order to obtain good performance and meet the requirements of glass composites products in specific parameters, artificial neural network technology was adopted to optimize and design the pultrusion process. The results showed that the curing degree of products increased gradually with the preheated mould temperature. During the reverse design of glass composites products, it was found that when the spread is 0.3, the measured temperature values of every stage based on curing degree were in good agreement with the forecasting values, which proved the correctness of the reverse design. The research method in this paper provides important theoretical basis and technical support for similar products.

The effect of growth temperature on the surface morphology and crystalline structure of InAs/GaSb type-II superlattices (SLs) grown on (100) GaSb substrates by metalorganic chemical vapor deposition (MOCVD) was investigated by in-situ reflectance measurement, atomic force microscopy, high-resolution x-ray diffraction and Raman scattering spectroscopy. All the data show that the structural properties of the SL samples are very sensitive to the growth temperatures. The optimal SL growth temperature in our MOCVD is 520 °C. Only 20 °C lower of the temperature resulted in rough surfaces from the beginning of SL epitaxy and 20 °C higher resulted in the composition of the mixing interfaces far from expected and consequently deteriorated structure. Room temperature absorption from 2 to 8 μm has been realized by our samples.

The graphite particles and Al2O3 short fibers reinforced AZ91D-0.8%Ce composites were fabricated by squeeze-infiltration technique. The researches about the effects of different graphite particle sizes on the microstructure and wear property of the composites were performed under the condition of constant contents of graphite particles and Al2O3 short fibers. The results reveal that the grain size of the composites changes less when the graphite particle size descends. Moreover, Ce enriches around the graphite particle and Al2O3 short fibers and forms A13Ce phase with Al element. The graphite that works as lubricant decreases the wear loss. The wear resistance of the composites increases as the graphite particle size increases. At low load the composites have similar wear loss; at high load the composite with the largest graphite particle size has the best wear resistance. The wear mechanism of all the composites at low load is abrasive wear and oxidation wear; at high load, except the composites with the particle size of 240μm whose wear mechanism is still abrasive wear and oxidation wear, the wear mechanism of others changes to delamination wear.

In this paper, the sulfate resistance properties of concrete under loading action are studied. The concrete specimens with different water/cement ratio are prepared and correlative corrosive experiments are carried out under single damage factor (SDF) and multiple damage factors (MDF), which is relative with drying and wetting cycles. Dynamic elastic modulus is taken to characteristic the sulfate resistance properties of concrete under the action of loading, drying and wetting cycles and sulfate corrosion. Results show the corrosion mechanisms of sulfate attack due to single damage factor and multiple damage factors were not all the same, and multiple damage factors could indicate the concrete structure due to sulfate attack more exactly.

InAs/InP quantum dot (QD) microcylinder lasers with an output waveguide are fabricated. Single-mode lasing wavelength of 1441 nm with side-mode suppression ratio around 24 dB is achieved from QD excited states emission.