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With the continuous increase of global population and consumption of resources, the dire need for an efficient and reliable energy system is becoming progressively prominent. The current energy system is still heavily dependent on fossil fuel, which is limited and harmful to the environment. In recent years, many countries have taken the initiative to transition into a phase where renewable and clean energy sources are gradually replacing fossil fuels and applied in various scenarios from residential buildings to power grids. However, renewable energies has their intrinsic drawbacks because of their intermittent and fluctuating nature. Consequently, it is crucial for the energy storage system to be highly capable in terms of storage capacity, instant supply, and durability. Among various energy storage systems, lithium-ion batteries have emerged as a preferable choice because of its high capacity, chemical and thermal stability, and gradually decreasing cost. In this dissertation, we developed a series of composite electrode materials for lithium-ion batteries of high performance and low cost. Carbonaceous materials have been reported to improve the battery performance to a certain extent. However, the lack of focus in the designing of the architecture of the carbon materials could limit the effect that they might bring. We thus developed an intercalation method that allows FeCl3 to be directly embedded into the graphite matrix to synthesize LFP/Graphite as a cathode material. This method significantly increased electronic and ionic conductivity through a robust and highly conductive graphite matrix, tremendously improving the performance of commercial LFP to a reversible capacity of 160 mA h g-1, a rate performance of 107 mA h g-1 at 60 C, and an outstanding cycling ability of > 95% reversible capacity retention over 2000 cycles.The intercalation method is then combined with Fe2O3 to improve the performance of graphite, which is the most prevalent material of the anode market. Graphite scaffold made via the intercalation process was able to provide a stable supporting structure to prevent structural failure due to large volumetric expansion and a highly electroconductive network. We synthesized a high-performance anode material with a specific capacity of 391 mAh/g after 350 cycles of charging/ discharging @ 500 mA/g, which improved the capacity of graphite by 50%.With rapidly growing world population and economy growth, the need for high-energy batteries with fast-charging capability is surging. Thus, it is essential to strategically combine materials so that while maintaining a high capacity and energy density, they could also exhibit an ability to accept fast charging. Graphene has been numerously studied and applied in composite materials in recent years, but its performance in terms of fast-charging has always been less than satisfactory because of both the poor quality of graphene, and the irreversible stacking of 2D structure within graphene. With this beard in mind, we designed synthesis processes for a hierarchical flower-like nitrogen-doped graphene-based LiFePO4 composite material for cathodes, and high-quality mesoporous graphene particles for high-energy and fast-charging anodes.In a hierarchical flower-like nitrogen-doped graphene-based LiFePO4 composite, we used a template-based process to obtain a CVD-grown nitrogen-doped graphene; the structure was able to withstand acid etching and subsequent charging/discharging processes, remaining at a ~100% coulombic efficiency at a high rate of 20C. In high-quality mesoporous graphene particles, we strategically combined a robust yet flexible graphene network with LFP nanoparticles that are closely packed. Followed by a microwaving process to largely increase the quality of the graphene to better provide an excellent electronic and ionic conducting network. The HNMG electrode provides a reversible capacity of 448 mA h g-1 even at a high charge-discharge rate of 60 C, 3 times the capacity of the NMG electrode (163 mA h g-1) and 70 times the capacity of the graphite electrode (6 mA h g-1). HNMG electrode also shows an excellent reversibility. Besides, due to the high tap density (0.63 g cm-3) of HNMG particles, the volumetric capacity of 334 mA h mL-1 at a high rate of 60C. These methods provided potential solutions to the current issues of electrode materials of LIBs by synthesizing a series of carbon-based composite materials with unique designs targeting the conductivity issue of high-performance materials.

In the past few years, the all-solid lithium battery has attracted worldwide attentions, the ionic conductivity of some all-solid lithium-ion batteries has reached 10−3–10−2 S/cm, indicating that the transport of lithium ions in solid electrolytes is no longer a major problem. However, some interface issues become research hotspots. Examples of these interfacial issues include the electrochemical decomposition reaction at the electrode-electrolyte interface; the low effective contact area between the solid electrolyte and the electrode etc. In order to solve the issues, researchers have pursued many different approaches. The addition of a buffer layer between the electrode and the solid electrolyte has been at the center of this endeavor. In this review paper, we provide a systematic summarization of the problems on the electrode-solid electrolyte interface and detailed reflection on the latest works of buffer-based therapies, and the review will end with a personal perspective on the improvement of buffer-based therapies.

Even though high-strength steel has been widely used across the world, the global buckling behaviour of high-strength steel beams has yet to be systematically investigated through experimental tests and numerical simulations. This paper describes an experimental and numerical study of the lateral-torsional buckling resistance of welded Q690 steel beams. Eight beams with doubly-symmetric cross-sections and different height-to-width ratios were tested under a concentrated point load. To allow free lateral deflections, a special loading system was designed and erected at the mid-span of steel beams. The applied load remained in the vertical direction during the whole loading process, despite significant rotations and lateral deflections of the beam. The critical bending moment of steel beams was quantified in the experimental tests. Besides, numerical models were established by using ABAQUS and initial imperfections were properly defined in the model. Direct comparisons were made among numerical results of steel beams of different steel grades and design curves in different standards. Based on experimental and numerical results, recommendations were provided for the lateral-torsional buckling design of Q690 steel beams. It was suggested that GB50017-2003 and GB50017-201X can predict the buckling resistance of Q690 steel beams with slightly conservative results, Eurocode 3 yields rather conservative estimations, but ANSI/AISC360-10 significantly overestimates the buckling resistance.

The wear and corrosion resistance of Ni-based niobium carbide (NbC) coatings were investigated via scanning electron microscopy, energy dispersive spectrometry, particle size analysis, X-ray diffraction, electrochemical polarization, electrochemicl impedance spectroscopy, digital microhardness testing and wear testing. The results showed that the substrate was mainly composed of a γ-Cr (Fe) solid solution, and the composite coating was composed of FeNi, NbC, and Ni. In addition, the hardness of the coating increased gradually with increasing NbC content. The optimal corrosion resistance and wear resistance of the coating were realized at an NbC content of 20%.

An axisymmetric model scramjet assisted with cavity flameholder is numerically investigated. Three-dimensional Reynolds-averaged Navier-Stokes simulation is carried out to reveal the fuel mixing and combustion characteristics. The simulation results show reasonable agreements with experimental data. The analysis indicates that the axisymmetric and rectangular scramjet has some similarities to the cavity shear layer in the nonreacting flow field. The configuration of the cavity shear layer changes hugely due to the significant chemical reaction and heat release in the reacting flow field. Typically, two more configurations with different cavity aft wall angles are compared with the experimental configuration to optimize the configuration of the cavity. When the cavity aft wall angle is small, the cavity shear layer bends to the cavity floor and more fuel enters into and stays in the cavity, which results in poor fuel mixing performance. With the increase of the aft wall angle, the fuel distributes more uniformly and the fuel mixing efficiency improves. In the reacting flow field, the volume of the cavity full of hot products and free radicals increases while the interaction between the cavity and main flow decreases with the increase of the aft wall angle. The improved combustion efficiency shows that larger cavity volume weighs more than reduced interaction between the cavity and main flow. The combustion is more violent in the case with a larger aft wall angle. Therefore, a proper increase of the aft wall angle is beneficial to the performance of cavity-assisted axisymmetric scramjet when designing the cavity flameholder.

In the current work, cost-effective, high efficiency, eco-friendly and biodegradable absorption adsorbents were prepared by loading rhodamine onto the surface of poly (butylene succinate) (PBS) electrostatic spinning film for the water purification. The adsorbability to heavy metal ions (such as: Hg(II) and Ag(I)) and dyes (such as: Congo red(CR), Crystal violet(CV)) were investigated. After the coating, it was found that PBS fibrous membranes exhibited better adsorption capacity toward these metal ions and dyes. Based on surface complex and electrostatic interaction mechanisms, the maximum adsorption capacity of Hg(II), Ag(I) CR and CV were 122.3, 91.2 138.5 and 109.4 mg/g respectively. Then the dynamic adsorption was tested of CR and CV by the suction filter, and the adsorption capacity of CR and CV were 111.2 and 83.0 mg/g within 10 s. What’s more, studies on adsorption kinetics and adsorption isotherms showed that the adsorption behavior of the modified PBS fibrous membrane could be well described by the pseudo second-order model, which means the adsorption process transform from physical adsorption (pure PBS) to chemisorptions (rhodamine/PBS). This study provides the eco-friendly method to fabricate polymer adsorbent to remove heavy metal ions and organic dyes from wastewater.

A chitosan/deoxyribonucleic acid (CHI/DNA)5 coating was constructed by layer-by-layer (LbL) assembly dip coating method with Mg(OH)2 coating as an inner protective layer on AZ31 alloy. X-ray diffractometry, X-ray photoelectron spectrometry, Fourier transform infrared spectroscopy and field-emission scanning electron microscopy were utilized to represent the chemical compositions and surface morphologies of the coatings. Electrochemical tests and hydrogen evolution measurements were implemented to confirm the good corrosion resistance of the composite coating in artificial body fluid. Antimicrobial activity of the composite coatings was tested via the plate-counting method, and the cytotoxicity of the samples was appraised by MTT assay and Live/dead staining. A double action was put into effect for the composite coating, which the inner Mg(OH)2 coating plays the part of physical barrier, and the outer (CHI/DNA)5 coating is employed as an inducer to fabricate a biocompatible Ca-P corrosion product coating during immersion, making up for its thin thickness. Otherwise, the composite coating is also beneficial for the growth of bone, resulting from the biomineralization effect of the outer polyelectrolyte multilayer. The good antibacterial property of the (CHI/DNA)5/Mg(OH)2 coating is ascribed to the contact-killing strength of CHI. Thus, the obtained (CHI/DNA)5/Mg(OH)2 coating has a wide application prospect in the field of Mg-based bone implantation.

High-temperature tensile tests at 25, 150, 250, and 350°C were carried out on 30CrMo, 42CrMo, 1Cr13, and 304 steels. The changes in tensile strength, yield strength, elongation, and area reduction ratio with temperature were determined. By analyzing the fracture morphology and the relationship between strength and hardness, the influence of high-temperature mechanical properties on crack sensitivity and the mechanism of crack formation is discussed. Experimental results indicated that both the tensile and yield strengths of the four steels gradually decrease with the increase in temperature. The yield ratios of 30CrMo, 42CrMo, 1Cr13, and 304 steels are, respectively, 0.71–0.77, 0.79–0.86, 0.84–0.88, and 0.33–0.40 which shows that among the four steels, 304 has the best ductility, while 1Cr13 has the worst ductility. As for the four steels, the values of reduction ratio of area are greater than 60%, except for 42CrMo which is slightly lower than 60% at 150 and 250°C, indicating that the four steels have low crack sensitivity within the test temperature range. Ductile fracture is the main fracture mechanism for 30CrMo, 42CrMo, and 304 steel, whereas brittle fracture is predominant for 1Cr13. There is a linear regression relationship between the strength and hardness at different temperatures. The obtained linear regression relationship can be used to predict and estimate the strength of 30CrMo, 42CrMo, 1Cr13, and 304 steels at different temperatures according to the hardness results.

Lapping ceramic balls with variable-radius groove plate (VRGP) has obvious advantages in achieving good consistency of batch manufacturing of ceramic balls. The material removal model of a single ball was established based on Hertz contact theory. Then, combining the previous research works based on kinematic analysis and the material removal model, the forming process of single ball was simulated and evaluated by the deviation from spherical form (∆Sph). After lapping period of 10 h, the experimental deviation ∆Sph decreased from about 0.233 to 0.0324 μm, and its maximum error between experimental and simulation values is 17.7%, indicating that the simulation results of variation of ∆Sph with time were mostly consistent with the experimental results. The validity of material removal model of lapping ceramic balls was verified experimentally.

Solar steam generation has attracted interest in recent years as a clean source for power generation and water treatment. To achieve a high rate of steam generation, it is important for the solar e...

Lithium sulfur battery (LSB) is widely considered as a next-generation battery system due to its high theoretical energy density of 2567 Wh kg−1. However, several inherent issues obstruct the business application of LSB. To address these issues, we assemble core–shell structure Fe3O4@C nanodots with 5 nm diameter as a valid sulfur host via a convenient organic pyrolysis treatment followed by calcination. The nanosized Fe3O4 particles could expose more chemisorption sites and inhibit the polysulfides shuttle. Moreover, the carbon layer could not only increase the conductivity but also ensure structural integrity during cyclic process. Furthermore, the mesoporous channels around Fe3O4@C could supply sufficient space to load sulfur and physically restrict the shuttle of polysulfides. Thus, the resultant S/Fe3O4@C cathode shows a highly initial capacity of 1089 mAh g−1 at 0.2 C, even retains 655 mAh g−1 over 200 cycles at 1 C.

An l -cysteine-bioinspired calcium phosphate (Ca-P) coating is prepared upon magnesium alloy AZ31 in a water bath at 60 °C. FE–SEM, FTIR, XRD, electrochemical characterization, hydrogen evolution tests and XPS were used to evaluate the microstructure, chemistry and corrosion performance of the samples. Results indicate that l -cysteine promotes the nucleation process of the coating and significantly increases its thickness. This can be attributed to the complexation of the carboxyl group and mercapto group of l -cysteine with calcium ions. Indeed, the obtained Ca-P coating possesses higher corrosion resistance than that prepared in l -cysteine-free bath.

Basically, Mg–Al layered double hydroxide (LDH) coatings are prepared on the surface of micro-arc oxidation (MAO) coated magnesium (Mg) alloys at a high temperature or a low pH value. This scenario leads to the growth rate of LDH coating inferior to the dissolution rate of the MAO coating. This in turn results in limited corrosion resistance of the composite coating. In this study, a Mg–Al LDH coating on MAO-coated Mg alloy AZ31 is prepared through a water bath with a higher pH (13.76) at a lower temperature (60 °C). FE-SEM, EDS, XRD, XPS, and FT-IR are applied to analyze the surface morphology, chemical compositions, and growth process. Electrochemical polarization, electrochemical impedance spectroscopy (EIS) and hydrogen evolution tests are employed to evaluate the corrosion resistance of the samples. The results disclose that the MAO coating is completely covered by the nanosheet-structured LDH coating with a thickness of approximately 3.8 μm. The corrosion current density of the MAO-LDH composite coating is decreased four orders of magnitude in comparison to its substrate; the presence of a wide passivation region in anodic polarization branch demonstrates its strong self-healing ability, indicating the hybrid coating possesses excellent corrosion resistance. The formation mechanism of the LDH coating on the MAO-coated Mg alloy is proposed. Furthermore, the cytocompatibility is assessed via an indirect extraction test for MC3T3-E1 pre-osteoblasts, which indicates an acceptable cytocompatibility of osteoblasts for the composite coating., Graphical abstract Image 1, Highlights • High pH and low temperature balance MAO dissolution rate and LDH growth rate. • EDTA-2Na accelerates the growth of LDH. • MAO-LDH coating shows a wider passivation zone and a seal-healing ability. • MAO-LDH coating has an acceptable biocompatibility for MC3T3-E1 osteoblasts. • The growth mechanism of MAO-LDH coating is proposed.

Drug-drug self-delivery systems serving as both carriers and cargos have been explored as advanced combination chemotherapy strategies to overcome the limitations of the traditional single-drug chemotherapy. However, most known drug-drug self-delivery systems may cause a rapid increase in drug concentration when the single covalent bond is broken, thus leading to high toxicity to organs and low therapeutic efficiency against tumors. To address the above problem, in this study, a novel supramolecular drug-drug complex (SDDC) simultaneously containing both covalent and noncovalent bonds was proposed to realize the sequential release of two drugs in tumor cells for enhanced combination therapy. The SDDC could self-assemble into uniform bilayer supramolecular vesicles (SVs) with a remarkable drug loading capacity and stable drug transport. Notably, the SVs with controlled sequential release ability in tumor cells exhibited a superior synergistic effect and significantly improved therapeutic efficiency with reduced toxicity in

The present study envisaged the WC-reinforced nickel composite coatings prepared on the surface of 4145H steel using the plasma transferred arc (PTA) method. The effects of different content of Y2O3 on the microscopic morphology, phase composition, micro-hardness and wear behavior were investigated by scanning electron microscopy (SEM) with an energy-dispersive spectrometer (EDS), X-ray diffraction (XRD), micro-hardness test and wear experiments. The deposited coatings consisted of WC-reinforced Ni59 composite coatings with the addition of 0 wt%, 0.5 wt% and 1 wt% Y2O3. Microstructural observation showed that the addition of 0.5 wt% Y2O3 had a better improvement on the coarse dendrites and the grain refinement. The main phase composition of the composite coatings was γ-Ni, FeNi3 solid solution, γ(Fe, Ni) eutectic phase, and the hard phase of WC, W2C. The cladding layer added with 0.5 wt% Y2 O3 was preferable over the Y2O3-free coating, as the microhardness was improved from 500 HV to 800 HV with a slight fluctuation of values. The coating with 0.5 wt% Y2O3 offered an excellent wear resistance to the extrusion and cracks for the uniformity of organizational structure compared with the substrate and the other two coatings. Furthermore, the results of weightlessness and coefficient of friction proved the positive effect of the rare earth Y2O3 on the wear resistance.

Nickel-based composite coatings reinforced by spherical tungsten carbide were deposited on 42CrMo alloy steel using plasma transfer arc welding (PTAW) process. Their electrochemical corrosion properties in NaCl solution under atmospheric and high pressure were studied by polarization curve, electrochemical impedance spectroscopy. The corrosion and erosion resistance of the coatings were also investigated by salt spray corrosion and erosion corrosion tests. The results show that the self-corrosion potential of the composite coatings increased with the increase of tungsten carbide content, and the Cr element in Ni60 sample formed a stable and compact passivation film. Compared with corrosion at atmospheric pressure, the adsorption and penetration of Cl- on the coating surface enhanced due to the increase of Cl- activity under pressure, thereby to weaken the corrosion resistance. The Samples that passivated in salt spray environment, cannot completely hinder the corrosion of the coating, just only to slow down the corrosion. This study can provide theoretical basis for deep-sea oil drilling and production engineering equipment.

Enhancing the circular dichroism signals of chiral plasmonic nanostructures is vital for realizing miniaturized functional chiroptical devices, such as ultrathin wave plates and high-performance chiral biosensors. Rationally assembling individual plasmonic metamolecules into coupled nanoclusters or periodic arrays provides an extra degree of freedom to effectively manipulate and leverage the intrinsic circular dichroism of the constituent structures. Here, we show that sophisticated manipulation over the geometric parameters of a plasmonic stereo-metamolecule array enables selective excitation of its surface lattice resonance mode either by left- or right-handed circularly polarized incidence through diffraction coupling, which can significantly amplify the differential absorption and hence the intrinsic circular dichroism. In particular, since the diffraction coupling requires no index-matching condition and its handedness can be switched by manipulating the refractive index of either the superstrate or the substrate, it is therefore possible to achieve dynamic tuning and active control of the intrinsic circular dichroism response without the need of modifying structure parameters. Our proposed system provides a versatile platform for ultrasensitive chiral plasmonics biosensing and light field manipulation.

Two kinds of Co-based coatings were obtained through the laser cladding (LC) and plasma transfer arc (PTA) process. The phase composition and microstructure of the coatings were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The corrosion behaviour of the different Co-based alloy coatings in 3.5wt% NaCl solution were compared by means of open-circuit potential (OCP), polarization curve and electrochemical impedance spectroscopy (EIS). XRD and SEM measurements demonstrated that the microstructures of the two different Co-based coatings were composed of primary solid solution γ-Co and eutectic structure Cr23C6, whereas, fish-bone typed (CoCrW)6C was also detected in the coating produced by PTA. The polarization curves and EIS results showed that in 3.5wt% NaCl solution, the passivation zones of the two coatings occurred obviously, the self-corrosion potential of the two coatings shifted to the right, and the self-corrosion current density was much smaller than that of the substrate. In addition, the Co-based coating made by LC showed lower corrosion current density and larger diameter of a capacitive arc than that of Co-based coating produced by PTA, indicating the LC coating had the best corrosion resistance in the three samples.

Fe-based coatings reinforced by spherical tungsten carbide were deposited on 304 stainless steel using plasma transferred arc (PTA) technology. The composition and phase microstructure of the coatings were evaluated using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The corrosion behaviors of the coatings in 0.5 mol/L HCl solution were studied using polarization curve and electrochemical impedance spectroscopy (EIS) measurements. The experimental results shows that the tungsten carbide improves the corrosion resistance of the Fe-based alloy coating, but increase in the mass fraction of tungsten carbide leads to increasing amount of defects of holes and cracks, which results in an adverse effect on the corrosion resistance. The defects are mainly present on the tungsten carbide but also extend to the Fe-based matrix. The tungsten carbide, acting as a cathode, and binding material of Fe-based alloy, acting as an anode, create a galvanic corrosion cell. The binding material is preferentially corroded and causes the degradation of the coating.

Black TiO₂-graphene oxide (GO) nanocomposites are synthesized via the pulsed laser ablating TiO₂ powders and GO in deionized water. The simple process enables the preparation of black TiO₂ nanoparticles and anchors them onto the GO sheet in one step. The TiO₂-GO nanocomposites exhibit greatly enhancement for photocatalytic degradation of Rhodamine B (RB) dye in comparison with the pristine and the ablated black TiO₂. The heterojunction structure plays an important role in efficient charge separation, which reduces the recombination of photogenerated electrons and holes. The unique two-dimensional structure of GO enables the composite to have a large specific surface area, and prevents the agglomeration of TiO₂ nanoparticles, which are beneficial to the photocatalytic performance of the composite.

TiO2/sericite (Ser) was prepared by depositing a nano-TiO2 film onto a carrier composed of sericite, an inorganic and nonmetallic mineral. Ultraviolet-resistant and antibacterial layers were then separately loaded onto the nano-TiO2 film, forming a multifunctional composite. The obtained functional TiO2/Ser composite was used as a filler and introduced into a rubber composite. It was indicated that the functional TiO2/Ser composite was straightforward, cost-effective, and easy to prepare under a low temperature. The nano-TiO2 layer exhibited a high loading capacity and was firmly loaded onto the inorganic and nonmetallic mineral carrier. The morphology and structure of the filler were observed using transmission electron microscopy. Moreover, the air permeability, antibacterial, aging-protection, and mechanical properties were measured and analyzed using the functional TiO2/Ser as a filler for SBR/TRR blend rubber. Compared with silica, the TiO2/Ser filler could reduce the material cost and improve the density, antibacterial, aging-protection, and mechanical properties of the SBR/TRR blend rubber.

Polyaniline (PANI) is a conductive polymer that allows cellulose aerogels to achieve high electrical conductivity. However, aerogels containing PANI alone display a low mechanical stability. Graphene nanosheets (GNS) display high conductivity and mechanical strength but are prone to agglomeration, hindering their electroactive sites. To avoid shortcomings of the individual components, a composite aerogel was prepared via addition of graphene nanosheets (GNS) and PANI to a suspension of cellulose nanofibril (CNF). Transmission electron microscopy and scanning electron microscopy were used to analyze the structural morphology of the CNF/GNS/PANI aerogel. The electrochemical properties were analyzed using a four-probe conductivity meter, cyclic voltammetry, galvanostatic charge-discharge tests, and electrochemical impedance spectroscopy. A 2:2:1 ratio of CNF/GNS/PANI provided optimal structural and electrochemical results. Incorporation of PANI through in-situ polymerization for 6 h resulted in uniform mixing of the three components. The CNF/GNS/PANI composite aerogel displayed a high electrical conductivity with a specific capacitance of 375 Fg-1 at a current density of 0.2 Ag-1. As a base binder and dispersant, CNF made use of PANI as a conductive medium and of GNS as a conductive reinforcing medium to form a flexible nanocellulose composite conductive material with increased stability and improved performance.

Alginate dressings can be used as a new type of lithium-ion battery separator with high thermal stability, excellent electrolyte adsorption/retention ability, and environmental friendliness, showing a broad application prospect in high safety lithium ion batteries.

With the increasing application of polyvinyl alcohol (PVA) films in the field of food packaging, it is important to improve its mechanical and antibacterial properties. This paper focuses on the preparation of PVA nanocomposite films and how their properties are affected by a silver-loaded nanocellulose solution. Cellulose nanocrystals (CNCs) were used as both the carrier and the dispersant of silver nanoparticles (AgNPs) prepared using glucose as the reducing agent. Ag+ was stabilized by the many hydroxyl groups located in the CNCs, and then the Ag+ was reduced to AgNPs in situ. After addition of silver-loaded nanocellulose, the tensile strength of the CNC-PVA-AgNP films increased from 47 MPa to 73 MPa, and the nanocomposite films displayed reduced moisture absorption and good antibacterial properties.

Photonic generation of a low-phase-noise microwave signal based on period-one (P1) dynamics of an optically injected semiconductor laser (OISL) subject to subharmonic modulation from an optoelectronic oscillator (OEO) is firstly proposed and experimentally demonstrated. Under suitable injection parameters, an OISL can be driven into period-one (P1) dynamics, which can be regarded as a photonic microwave with a relatively large linewidth. By further introducing an OEO with a frequency of 1/2 P1 frequency to directly modulate the OISL, a low-phase-noise photonic microwave with P1 frequency can be obtained. For an OISL operating at P1 oscillation with a frequency of 16.96 GHz, after imposing a 1/2 subharmonic modulation of 8.48 GHz on the OISL by an OEO, the photonic microwave linewidth is reduced from 5.23 MHz to less than 1 kHz, and the single sideband (SSB) phase noise of the final photonic microwave is -102.5 dBc/Hz@10 kHz, which is close to the SSB phase noise of the OEO signal (-104.3 dBc/Hz@10 kHz).

This study developed a model involving the energy balance and decomposition at the ablated interface due to the heat transport, optical decomposition and activation energy in Acrylonitrile Butadiene Styrene/PolyVinyl Chloride (ABS/PVC). The prediction for ablation depth obtained from this study is compared with the available experimental data. The predicted results agree with the measured data. The effects of laser processing parameters, optical and thermal properties of ABS/PVC on the variation of the laser-ablated depth with the laser fluences are also discussed. The results validate that the pulsed-laser ablation rate at the initial short period is dominated by optical penetration absorption for laser and is linearly proportional to the logarithm of the laser fluence by a ratio factor “optical absorption length” (i.e., the ablation rate follows Beer’s law at the initial short period).

Soil–rock mixtures is a special engineering geological material and often used as a roadbed filler. Based on the orthogonal experimental method, a series of large-scale triaxial tests of soil–rock ...

Based on a current modulated semiconductor laser (SL) subject to optical injection, tunable and broadband microwave frequency comb (MFC) generation is theoretically investigated. For a SL under only current modulation, a seed MFC with relatively narrow bandwidth can be generated. Then, an optical injection is introduced to improve the quality of seed MFC. Furthermore, the influences of operation parameters on the performance of MFC are also discussed. The numerical results show that after introducing optical injection with injection coefficient k = 1.8×10-4 and detuning frequency Δf = 6.0 GHz, the MFC bandwidth can be further increased by 15.6 GHz and the signal-to-noise ratio can be improved by more than 20 dB.

Frequency-modulated continuous-wave (FMCW) can be acquired by using a distributed feedback semiconductor laser (DFB-SL) operating at period-one (P1) oscillation under an optical injection modulated by a Mach–Zehnder modulator (MZM). In this work, through introducing another MZM to establish cascade-modulated optical injection, an improved photonic scheme for generating high-quality FMCW is proposed and experimentally demonstrated. The experimental results indicate that, under appropriate injection parameters, the central frequency of the generated FMCW is widely tunable, and the bandwidth is larger than that obtained under a single MZM modulation. Further introducing optical feedback for suppressing the phase noise, the frequency comb contrast of the generated FMCW can be improved obviously.

Stimuli-responsive nanomachines are attractive tools for biosensing, imaging, and drug delivery. Herein, we demonstrate that the orientation of macromolecules and subsequent dynamic interactions at the biomolecule-nanoparticle (bio-nano) interfaces can be rationally controlled to engineer stimuli-responsive DNA nanomachines. The success of this design principle was demonstrated by engineering a series of antibody-responsive DNA walkers capable of moving persistently on a three-dimensional track made of DNA functionalized gold nanoparticles. We show that drastically different responses to antibodies could be achieved using DNA walkers of identical sequences but with varying number or sites of modifications. We also show that multiple interfacial factors could be combined to engineer stimuli-responsive DNA nanomachines with high sensitivity and modularity. The potential of our strategy for practical uses was finally demonstrated for the amplified detection of antibodies and small molecules in both buffer and human serum samples. Unlike many DNA-based nanomachines, the performance of which could be significantly hindered by the matrix of serum, our system shows a matrix-enhanced sensitivity as a result of the engineering approach at the bio-nano interface.

The basis for pulling a passive nanostructured material using laser light by establishing a transverse surface plasmon resonance on the back of a membrane is presented and supported with both theory and numerical simulations. The total force magnitude and direction can be regulated by electromagnetic resonant modes interacting with materials that can be adjusted using the material and geometry variables, and with plane-wave illumination under sinusoidal steady-state conditions. In the situations treated, the structured material is fixed in position and the force density and hence total force are determined numerically. Simulations indicate that a silicon nitride film coated with gold and patterned to produce a unit cell having a slot passing through both materials allows satisfactory surface wave control to facilitate a pulling force with visible wavelengths. When the plasmon surface wave on the back dominates, pulling occurs, and when the mode on the front has more energy, the result is pushing. It is also shown that pushing or pulling, regulated by varying the wavelength of the incident light, is possible, and an example is presented. This work motivates an experimental effort to investigate pulling with nanostructured media and offers a different paradigm in optomechanics.

In the presence/absence of N-donor ancillary ligands, through utilizing two well-designed chiral 4,4′-oxybisbenzoyl alanine/proline derivatives, two new Cu(II)-bearing coordination polymers whose chemical formulae are [Cu(ODBALa)H2O]·H2O (1, H2ODBALa = 4,4′-oxybisbenzoyl-bis(L-alanine)) and [Cu(ODBPRo)(dpy)]·7H2O (2, H2ODBPRo = 4,4′-oxybisbenzoyl-bis(L-proline), dpy = (E)-1,2-di(pyridin-4-yl)diazene) have been fabricated via a solvothermal preparation method. The magnetic researches demonstrate that compounds 1 and 2 have antiferromagnetic catena among the neighboring metal ions. Their application values on the mixed vaginitis were assessed and the mechanism involved was also discussed. Firstly, after prescribed treatment, an ELISA (enzyme linked immunosorbent assay) detection was used to evaluated the inflammatory levels in the body. Apart from this, the real-time RT-PCR (reverse transcription-polymerase chain reaction) was performed and the Lactobacillus abundance was measured. Compound 1 was better than compound 2 on the vaginitis treatment.

To investigate how nodule size, nodule density, scan dose, slice thickness and reconstruction methods affect the performance of a deep learning (DL) model for detection of pulmonary nodules in phantom CT scans. Spherical lung nodule phantoms of two different densities (− 630 HU and + 100 HU) and five different sizes (3, 5, 8, 10, and 12 mm) were inserted into an anthropomorphic chest phantom. CT data were scanned and reconstructed using three different tube current (10, 50, 200 mAs), two different slice thickness of 1 and 2 mm, four reconstruction methods (FBP-standard (FBP-STD), FBP-Y sharp kernel (FBP-YA), iDose4-standard kernel (iDose4-STD) and iDose4-Y sharp kernel (iDose4-YA). Evaluation of deep learning model focused on detection sensitivity and precision. According to the statistical results from the study, we found that the sensitivity and precision performance depends on the nodule sizes, nodule type, tube current, reconstruction methods and image thickness. Comparing the solid (100 HU) and ground-glass (GGO, − 630 HU) nodule phantoms, solid nodule phantom predictions are rarely affected by tube current, reconstruction methods and nodule sizes. Both sensitivity and precision are close to 100% in all solid nodule phantom prediction cases. While the sensitivity and precision metrics of GGO nodule phantoms change in a wide range from 42.9 to 100%. Larger nodule size and higher tube current gives a better sensitivity and precision for GGO nodule phantoms in most cases. We also analyze the relationships between the image thickness and the reconstruction methods. For 1-mm thickness images, iDose4-STD and FBP-STD shows a better result in both sensitivity and precision metrics. As for 2-mm thickness images, iDose-YA and FBP-YA gain a better performance. The results of this phantom study demonstrated that high stability and flexibility of deep learning model can be used in daily clinical and screening practice.

Novel red-emitting phosphors LiGd9(SiO4)6O2:Eu3+ (LGSO:Eu3+) and NaGd9(SiO4)6O2:Eu3+ (NGSO:Eu3+) were successfully synthesized via a high-temperature solid-state reaction. The phase formation of LGSO:Eu3+ and NGSO:Eu3+ phosphors were characterized by X-ray powder diffraction (XRD). The phosphor could be evidently excited by the near ultraviolet (NUV) light and blue light and then exhibited red light emission, which confirmed by the photoluminescence excitation (PLE) and emission (PL) spectra. According to the photoluminescence spectra, the emission peaks of LGSO:Eu3+ and NGSO:Eu3+ are mainly locate at 595 nm and 615 nm, which attribute to the 5D0 → 7F1 and 5D0 → 7F2 transitions of Eu3+. A comparative study of the optical properties of Eu3+ in the AGd9(SiO4)6O2 (A = Li, Na) red phosphor shows that the optimum concentration of LGSO:Eu3+ phosphors x = 0.20 is less than that of NGSO:Eu3+, x = 0.50, and the emission intensity of the latter is always higher than the former at the same concentration. The ultraviolet–visible spectra indicated that both of hosts tend to absorb energy in the spectral range 200–350 nm, and the band gap of host and phosphor are calculated(LGSO = 3.80 eV, NGSO = 3.99 eV), and the doping of Eu3+ helps to reduce the band gap. The internal quantum efficiency (IQE) of LGSO:0.2Eu3+ and NGSO:0.5Eu3+ were 69.6% and 77.3%, respectively. The chromaticity coordinates of LGSO:0.2Eu3+ and NGSO:0.5Eu3+ were (0.638, 0.360) and (0.643, 0.356), which exhibited high color purity. On this basis, we come to a conclusion that the prepared phosphors enjoy tremendous potentials serve as red emitting phosphor for near ultraviolet white light emitting diodes (NUV WLEDs).

Structure and defect control are widely accepted effective strategies to manipulate the activity and stability of catalysts. On a freestanding hierarchically porous carbon microstructure, the tuning of oxygen vacancy in the embedded hollow cobaltosic oxide (Co3 O4 ) nanoparticles is demonstrated through the regulation of nanoscale Kirkendall effect. Starting with the embedded cobalt nanoparticles, the concentration of oxygen-vacancy defect can vary with the degree of Kirkendall oxidation, thus regulating the number of active sites and the catalytic performances. The optimized freestanding catalyst shows among the smallest reversible oxygen overpotential of 0.74 V for catalyzing oxygen reduction/evolution reactions in 0.1 m KOH. Moreover, the catalyst shows promise for substitution of noble metals to boost cathodic oxygen reactions in portable zinc-air batteries. This work provides a strategy to explore catalysts with controllable vacancy defects and desired nano-/microstructures.

With the rapid development of plug-in hybrid electric vehicles and electric vehicles, high-energy layered lithium nickel-rich oxides have received much attention, but there are still many challenges due to the inherent properties of materials. The poor cycling performance and initial capacity loss of the nickel-rich layered oxide are associated with the structural stability of the material and Li+/Ni2+ cation disorder. Moreover, the synergistic effect of the vacancy of Li and Ni in the delithiation process aggravates the instability of oxygen, eventually resulting in the release of oxygen. It can cause damage to the stability of the structure and even cause safety issues. In this work, we report that Ce0.8Dy0.2O1.9 solid electrolyte inhibits the release of oxygen and improves the structural stability and safety of the Ni-rich cathode material, which is rich in oxygen vacancies. Besides, Ni2+ could be oxidized to Ni3+ along with the strong oxidation of Ce4+ doping into the bulk structure, which suppresses the Li+/Ni2+ cation disorder and improves the initial Coulomb efficiency of the material. This study successfully designed a novel cathode material structure to provide a basis for the future development of layered lithium nickel-rich oxides, which can be used to improve the initial Coulomb efficiency and cycle life.

One of the major obstacles for the clinical use of biodegradable magnesium (Mg)-based materials is their high corrosion rate. Micro-arc oxidation (MAO) coatings on Mg alloys provide mild corrosion protection owing to their porous structure. Hence, in this study a dense Mg(OH)2 film was fabricated on MAO-coated Mg alloy AZ31 in an alkaline electrolyte containing ethylenediamine tetraacetic acid disodium (EDTA-2Na) to reinforce the protection. Surface morphology, chemical composition and growth process of the MAO/Mg(OH)2 hybrid coating were examined using field-emission scanning electron microscopy, energy dispersive X-ray spectrometer, X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared spectrophotometer. Corrosion resistance of the coatings was evaluated via potentiodynamic polarization curves and hydrogen evolution tests. Results manifested that the Mg(OH)2 coating possesses a porous nano-sized structure and completely seals the micro-pores and micro-cracks of the MAO coating. The intermetallic compound of AlMn phase in the substrate plays a key role in the growth of Mg(OH)2 film. The current density of Mg(OH)2-MAO composite coating decreases three orders of magnitude in comparison with that of bare substrate, indicating excellent corrosion resistance. The Mg(OH)2-MAO composite coating is beneficial to the formation of calcium phosphate corrosion products on the surface of Mg alloy AZ31, demonstrating a great promise for orthopaedic applications.

In this work, silicon carbide nanocrystals (SiC NCs) were prepared via ultrasonic vibration treatment on the electrochemical etched SiC target. TiO2/SnO2 powders were pulsed-laser ablated in deionized water with different duration. Then, the SiC NCs were coupled with the laser modified powders, forming the SiC-TiO2/SnO2 nanocomposites. As-prepared nanocomposites exhibit extended light absorption to the visible range. The abilities for photocatalytic degradation of the heterostructured catalysts were greatly enhanced in comparison with the pristine and the ablated TiO2/SnO2 powders. It was ascribed to the heterojunction structure between SiC NCs and TiO2/SnO2, which reduces the recombination of photogenerated electrons and holes.

The electronic structures, magnetic properties and half-metallicity of Heusler alloys CsYO2 (Y = V, Cr, Mn, Fe, Co, Ni) have been studied by first principles calculations. The results show that the six compounds are more stable in AlCu2Mn-type compared to in CuHg2Ti-type, and also more stable in the ferromagnetic (FM) state than in the non-magnetic (NM) state. Therefore, the electronic structures, magnetic properties and half-metallic stability of the six compounds were calculated and analyzed in the AlCu2Mn-type in the ferromagnetic ground state. It has been found out that the six compounds exhibited half-metallicity. Meanwhile, Y atom is the region of half-metallicity and magnetic moments of CsYO2 (Y = V, Cr, Mn, Fe, Co, Ni). The magnetic moments of all the six compounds were integers and satisfy the Slater-Pauling rule. In the process of changing the lattice constants of the six compounds and tetragonal deformation, the half-metallic properties kept stable within wide ranges.

Fe-based coatings reinforced by spherical WC particles were produced on the 304 stainless steel by plasma transferred arc (PTA) to enhance the surface wear properties. Three different Fe/WC composite powder mixtures containing 0wt%, 30wt%, and 60wt% of WC were investigated. The microstructure and phase composition of the Fe/WC composite PTA coatings were evaluated systemically by using scanning electron microscope (SEM) and X-ray diffraction (XRD). The wear properties of the three fabricated PTA coatings were investigated on a BRUKER UMT TriboLab. The morphologies of the worn tracks and wear debris were characterized by using SEM and 3D non-contract profiler. The experimental results reveal that the microhardness on the cross-section and the wear resistance of the fabricated coatings increase dramatically with the increasing adding WC contents. The coating containing 60wt% of WC possesses excellent wear resistance validated by the lower coefficients of friction (COF), narrower and shallower wear tracks and smaller wear rate. In the pure Fe-based coating, the main wear mechanism is the combination of adhesion and oxidative wear. Adhesive and two-body abrasive wear are predominated in the coating containing 30wt% of WC, whereas threebody abrasion wear mechanism is predominated in the coating containing 60wt% of WC.

We propose and theoretically study a silica double-toroid microcavity to confine the whispering-gallery mode (WGM) in an ultra-small space, which consists of two toroid-to-toroid coupled cavities separated by a nanoscale gap region with low refractive index, such as the air gap. Benefitting from the strong field localization of the “slot” effect, power enhancement of symmetric WGMs in the gap results in the ultra-small mode volume of 4. 8 μ m which is quite smaller than the conventional toroidal microcavity with mode volume of about hundreds of cubic micrometers. The confined modes hold the potential advantages over conventional photonic devices, especially in the applications of the sensing and optical trapping. In the application of refractometer, a high refractive index sensitivity of up to 468 nm per refractive index unit (nm/RIU) can be obtained in the 1000 nm wavelength band. In the optical trapping application, the double-toroid microcavity enables a significant field enhancement in the confined WGM, and the gradient force could reach as high as 22 pN/W for a single nanoparticle with the radius of 5 nm. As the potential advantages, this study of silica double-toroid microcavity provides a good reference for realizing the high-efficient photonic applications such as optical sensing and trapping.

A hexagonal nanosheet Mg(OH)2 coating was prepared through a one-step hydrothermal method using LiOH solution as mineralizer and then modified by ethylenediaminetetraacetic acid (EDTA) to minimize the rapid corrosion of AZ31 Mg alloy. The performance of the coating was evaluated using electrochemical technique, hydrogen evolution measurements, nanoscratch test, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) patterns and field-emission scanning electron microscopy (FESEM). The results suggested that the corrosion rate of bare AZ31 Mg alloys was significantly reduced by one and two orders of magnitude through the protection from Mg(OH)2 coating and modification with EDTA (i.e., EDTA-Mg(OH)2 coating), respectively. FESEM micrographs indicated that the modification in EDTA elicits to the formation of an EDTA-Mg(OH)2 composite with a thickness as twice as that of as-prepared Mg(OH)2 coating. Nanoscratch tests revealed strong adhesion between the composite or Mg(OH)2 coating and the substrate. The study of formation and corrosion mechanisms of the coatings manifested that Mg(OH)2 was first formed near the intermetallic compound AlMn particles and gradually covered the entire surface, wherein the AlMn particles played an important role in the coating growth process. And it also proved that EDTA accelerated the formation of Mg(OH)2.

A Ni-based alloy coating with 30 wt.% spherical tungsten carbide particles was prepared through plasma transferred arc welding on 42CrMo steel. The composition and microstructure of the coating were examined through X-ray diffraction and scanning electron microscopy with energy-dispersive spectrometry. The corrosion behaviors of the coating compared to the Ni coating without tungsten carbide particles and to the bare substrate in a 0.5 mol/L HCl solution were presented through polarization curves, electrochemical impedance spectroscopy (EIS) measurements and long-term immersion tests. The results demonstrated that the composite coating microstructure comprised Ni matrix, Ni-rich phase, tungsten carbide particles, W-rich phase and Cr-rich phase. The polarization curves and EIS measurements presented that a passivation film, which mainly included Ni, Cr, Fe and W oxides, was formed in the composite coating that protected the substrate from corrosion by HCl solution. In the immersion tests, a micro-galvanic reaction at the new-formed phases and Ni matrix interface caused severe pit corrosion and Ni matrix consumption. The debonding of Ni-rich and W-rich phases could be observed with the immersion time extension. The tungsten carbide particles and Cr-rich phase were still attached on the surface for up to 30 days.

A hybrid slot–groove casing treatment (CT) composed of front axial slots and rear circumferential grooves is experimentally studied in a low-speed axial compressor in consideration of stability and efficiency. Results show that the hybrid slot–groove CT can improve the stall margin by 19.79% with an efficiency penalty of 1.5%. Compared to full-groove and full-slot CTs, the hybrid slot–groove CT's stall margin improvement and minimization of efficiency loss are excellent. Detailed measurements indicate that, unlike smooth casing (SC), the hybrid slot–groove CT can unload the blade tip, weaken the tip leakage vortex, and improve the disturbance observed downstream to postpone stall. Given the influence of serious passage blockage derived from the hub region after improving tip flow capability under the hybrid slot–groove CT, the stall route and inception captured in the casing wall and different downstream radial positions demonstrate that, unlike the SC with a typical spike-type inception (short length-scale with 2–3 blade passages), the hybrid slot–groove CT creates a long length-scale stall inception (6–8 blade passages). In addition, a new type of instability inception with a different frequency band from the stall cell is found in the hub region under the hybrid slot–groove CT. This inception appears more than hundreds of revolutions before the fast trigger of spike-type inception and can be used as an early stall warning signal under high hub loading.

Nanofilms are of great interest as a kind of separation membranes for seawater desalination and wastewater treatment. Their fabrication, however, always needs a time-consuming process and shows low atom economy. Herein, we report pyrogallol/polyethyleneimine (PG/PEI) nanofilms spontaneously formed at the gas/liquid interface within ten minutes and composited on microporous substrates. Both the film thickness and the surface charge are facilely adjusted by the reaction time and the mass ratio of PG/PEI in aqueous solution. The solution is repeatedly used to fabricate the nanofilm composite membranes and thus this method is with high atom economy of raw materials. The as-prepared nanofilm composite membranes can be directly applied in aqueous nanofiltration, showing a relatively high water permeation flux (17.5 L m−2 h−1 bar−1) and salt rejection (>94% for MgCl2) during a long-term operation. The nanofilms are also demonstrated potentials in organic solvent nanofiltration after moderate cross-linking by glutaraldehyde.

Polyacetylacetonatozirconium was used as the precursor to synthesize ZrO2 aerogel (PAZ-ZrO2). The physical properties of the aerogel were compared with those generated from zirconyl chloride (ZOC-ZrO2) and zirconyl nitrate (ZON-ZrO2). PAZ-ZrO2 aerogel has higher compressive strength (0.12–0.23 MPa) with lower density (0.12 ± 0.005 g/cm3) as compared to ZOC-ZrO2 and ZON-ZrO2 aerogel, of which the mechanical strengths are in the range of 0.02–0.15 MPa and the density of 0.13–0.17 g/cm3. After being treated at 1000 °C, the surface area (pore volume) of ZOC-ZrO2, ZON-ZrO2 and PAZ-ZrO2 aerogel are 210 m2/g (1.299 cm3/g), 223 m2/g (0.444 cm3/g) and 236 m2/g (1.568 cm3/g) respectively.

In this work, a novel optoelectronic oscillator (OEO) structure is proposed for generating widely tunable photonic microwave. In this structure, an optical injection semiconductor laser (OISL) functions as an active tunable microwave photonic filter (MPF). Through controlling the injection power and frequency detuning, the OISL is driven into period-one dynamics whose oscillation frequency can be widely tuned from 10.43 to 65.82 GHz. As a result, the OISL can be regarded as a widely tunable active MPF. By introducing an optical feedback loop, the filtered bandwidth of the widely tunable active MPF can be further reduced. Taking the OISL under optical feedback as a widely tunable narrow-bandwidth MPF and a seeding laser source to establish an OEO structure, widely tunable narrow-linewidth photonic microwave can be generated. The experimental results demonstrate that widely tunable photonic microwaves ranging from 10.43 to 39.10 GHz with linewidths below 0.1 MHz and phase variances below 10-2 (rad2) can be achieved.