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Unconventional folded shielded coplanar waveguide (FS-CPW) has yet to be fully investigated for tunable dielectrics-based applications. This work formulates designs of FS-CPW based on liquid crystals (LC) for electrically controlled 0-360˚ phase shifters, featuring a minimally redundant approach for reducing the LC volume and hence the costs for mass production. The design exhibits a few conceptual features that make it stand apart from others, noteworthy, the dual-strip structure with a simplified enclosure engraved that enables LC volume sharing between adjacent core lines. Insertion loss reduction by 0.77 dB and LC volume reduction by 1.62% per device are reported at 77 GHz, as compared with those of the conventional single-strip configuration. Based on the proof-of-concept results obtained for the novel dual-strip FS-CPW proposed, this work provides a springboard for follow-up investible propositions that will underpin the development of a phased array demonstrator.

In order to clarify the suction characteristics of unsaturated clay under different conditions of water and salt, taking soil in western Jilin province, China as the research object, the suctions (matrix suction and osmotic suction) of samples with different water content, salt type, and salt content were determined by filter paper method. The results indicate that salt type and content have insignificant influence on the matrix suction. With the increase of water content, the matrix suction decreases at different rates in different suction regimes. When water content is constant, the osmotic suction increases with the increase of salt content, and under the condition of a constant salt content, the osmotic suction first increases and then decreases with the increase of ion concentration of the pore water, and can reach tens of MPa. The concept of suction equilibrium water content is proposed. When water content of sample is higher than this value, the magnitude of osmotic suction will always be greater than that of matrix suction. This indicates the necessity to consider osmotic suction in the presence or change of salt in soil. The applicability of the traditional models of matrix suction and osmotic suction in the full suction range of clay is discussed, and it is found that the traditional models cannot make a full explanation to the variation in suction. Based on the experimental data, an improved van Genuchten matrix suction model and an osmotic suction model, transformed by the Planck blackbody radiation formula, are proposed.

The demand for reconfigurable millimetre-wave (mm-Wave) components based on highly anisotropic liquid crystals (LC) is higher than ever before for the UK and worldwide. In this work, 60 GHz investigation on a bespoke shielded coplanar waveguide (SCPW) phase shifter structure filled with 16 types of microwave-enabled nematic LCs respectively indicates that the patterns of the device’s figure-of-merit (FoM, defined as the ratio of maximum differential phase shift to maximum insertion loss) reshuffle from those of the characterised LC materials’ FoM (defined as the ratio of tunability to maximum dissipation factor). To be more specific, GT7-29001- and MDA-03-2838-based phase shifters exhibit the highest FoM for devices, outperforming phase shifters based on GT5-28004 and TUD-566 with the highest FoM for materials. Such a mismatch between the device’s FoM and LC’s FoM implies a nonlinearly perturbed wave-occupied volume ratio effect. Furthermore, the relationship between insertion loss and the effective delay line length is nonlinear, as evidenced by measurement results of two phase shifters (0–π and 0–2π, respectively). Such nonlinearities complicate the established FoM metrics and potentially lead to a renewed interest in the selection and material synthesis of LCs to optimise reconfigurable mmWave devices, and promote their technological exploitation in phased array systems targeting demanding applications such as inter-satellite links and satellite internet.

Wear is one of the most common failure modes for metals, and therefore the development of low-cost coatings with enhanced wear resistance is of great importance. In the present work, M2 high-speed steel (HSS) coatings, constituted by martensite, carbides, and retained austenite, were prepared by laser cladding on 1045 carbon steel. The microstructure evolution, wear resistance, and wear mechanism of the M2 HSS coatings were systematically investigated. A possible microstructural evolution of the coating during the laser-cladding process is proposed. The prepared M2 HSS coatings exhibit enhanced hardness and wear resistance compared with the 1045 carbon steel substrate. It was found that the wear of the M2 HSS coating is dominated by abrasive wear, adhesive wear, and oxidation wear, while that of the 1045 carbon steel substrate is mainly dominated by oxidation wear. This work provides insight into the morphology evolution and the wear mechanism of the HSS coating prepared by laser cladding.

In this study, a blue-green pigment has been prepared by partially replace Co2+ and Cr3+ in CoCr2O4 spinel structure with Mg2+ and Al3+ using a gel casting method The gel precursor was calcined at various temperatures (900–1400 °C) to obtain Mg0.5Co0.5CrAlO4 spinel pigment. Combining the Rietveld refinement method of XRD and peak fitting of XPS high-resolution spectra, the relationships between the cation distributions (Co2+, Mg2+, Al3+, and Cr3+) in the tetrahedron and octahedron of the spinel structure and the calcination temperature were examined. In the octahedron, the contents of Co2+ and Al3+ decreased with increasing calcination temperature, and the Mg2+ and Cr3+ contents exhibited the opposite trend. The bond lengths of A-O and B–O change with increasing calcination temperature, thereby leading to a change in the unit cell. The optical performance of the pigments was investigated via UV–vis and CIE L*a*b* spectrophotometry, and the study shows that the blue-green hue of the pigment powder is caused by the absorption at υ3～υ8 (370 nm–640 nm) in the visible light region. The varied contents of Co2+ and Cr3+ in the spinel structure among calcination temperatures cause the absorption spectrum intensity change, thereby resulting in various blue-green tones. This study lays the foundations for subsequent investigations of colour modification in MgxCo1-xAlyCr2-yO4 spinel.

The damping properties of fluorinated polyacrylate (FPA) composites with expanded graphite (EG) partially substituted for mica as fillers have been studied. EG was prepared by a rapid expansion method by microwave (MW) irradiation. The effects of the EG and natural graphite (NG) as partial substitutions for mica and the blending of epoxy (EP) resin with the polyacrylate emulsion on the damping performance of the composites was investigated with dynamic mechanical analysis (DMA). The results showed that adding EG as a partial substitute for the mica improved the intensity of the loss peak of the DMA tanδ and broadened the corresponding high loss factor (tanδ > 0.3) temperature range of the PA/EP composites. In comparison with NG or the mica, EG was more efficient in improving the damping properties of the composites. When the weight content of EP was 4% and EG was 6%, tanδ reached the maximum value of 2.16, and the corresponding temperature range with tanδ > 0.3 was about 80 °C.

Hierarchical nanoparticles are of great interest because they possess unique physicochemical properties and multiple functionalities, providing a wealth of possibilities for various applications. In this work, we have developed a well-designed method to prepare hierarchical magnetic nanoparticles Fe3O4@mSiO2@CS by integrating a solvothermal method for synthesizing the Fe3O4 core, a dualtemplating micelle system for preparing a layer of mesoporous silica (mSiO2) shell, and a silane coupling method via γ-glycidoxypropyltrimethoxysilane for binding a chitosan (CS) layer on the silica surface. The porous hierarchical nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic light scattering nanoparticle size analyzer, and specific surface area and pore size analyzer. The loading capacity and the release behavior of the as-prepared nanoparticles for doxorubicin hydrochloride were studied, and it was found that the drug release rate was faster at pH 6.0 than at pH 7.4, revealing the pH-responsive property of the nanoparticles.

V-5Cr-5Ti alloys have been fabricated using a laser melting deposition (LMD) additive manufacturing process, showing precipitates aggregated near the grain/dendrite boundaries. Since the mechanical properties of vanadium alloys considerably depend on the precipitates, solution and aging treatments have been applied to eliminating the aggregations of the precipitates. The results show that as the solution temperature increases from 800 to 1560 °C, the densities and the lengths of the precipitates are reduced, while the widths of the precipitates are increased. When the solution temperature reaches 1560 °C, most impurity elements diffuse into the matrix and form into a nearly uniform supersaturated solid solution. Aging treatments have been applied to the 1560 °C solution treated samples. It shows that as the aging temperature increases from 800 to 1200 °C, the precipitate length increases, and the shapes of precipitates change from near-spherical to lath-like. Compared to 800 and 1200 °C, aging at 1000 °C results in the highest precipitate density. Compared to the LMD and solution-treated samples, the aged samples have the highest micro-hardness, due to the precipitation strengthening.

Biomass transformation is being considered as a green and sustainable strategy for carbon-based functional materials in many fields. To produce porous structure favorable for microwave absorption, we demonstrate herein the successful synthesis of macroporous carbon materials with cornstalk as a biomass precursor. It is found that two kinds of typical biological structures in cornstalk, linear vascular bundles and parenchyma cells, can be well preserved during high-temperature pyrolysis. Mercury intrusion porosimetry and N2 adsorption indicate that these cornstalk-derived carbon materials have very high porosity, which is mainly from desirable macroporous structure rather than conventional micro/mesopores. Electromagnetic (EM) analysis reveals that dielectric loss is the only pathway for the consumption of EM energy, and high pyrolysis temperature favors strong dielectric loss through conductive loss and interfacial polarization loss. Meanwhile, pyrolysis temperature also affects the matching degree of characteristic impedance. When the pyrolysis temperature reaches 750 °C, good dielectric loss and impedance matching endow the sample (CSC-750) with excellent microwave absorption performance, including strong reflection loss, broad response bandwidth, and relatively thin absorber thickness. The advantages of macroporous structure are further highlighted in impedance matching and multiple reflection by comparing with a macropore-free counterpart.

Organic light-emitting transistors (OLETs) integrate the functions of light-emitting diodes and field-effect transistors into a unique device, opening a new door for optoelectronics. However, there is still a challenge due to the absence of high quality organic semiconductors for OLETs. Herein, we reported a novel molecule 2,6-di(anthracen-2-yl)naphthalene (2,6-DAN), which exhibited mobility of up to 19 cm2·V−1·s−1 and an absolute fluorescence quantum yield of 37.09%, which are good values for organic semiconductors. Moreover, OLETs based on 2,6-DAN single crystals showed bright yellowish-green emission and well-balanced ambipolar charge transport. The excellent ratio of hole to electron mobility can reach up to 0.86, which is superior to most single-component OLETs in typical device configurations reported so far.

High entropy alloys exhibit a composition design route that different from conventional alloys. However, whether the high configurational entropy is the key factor that stabilizes the room temperature single phase solid solution is still under debate. Here we use a perturbation model to evaluate their phase stabilities. According to the calculation results of 7085 alloys, it clearly indicates that a stable single phase is rare when constituent elements increase. The effect of increased entropy cannot balance the fast-increased driving force for the formation of intermetallics. Although it is not favored by thermodynamics, the frequently observed room temperature single-phase solid solutions can still form due to dynamic effect, which from the other side, provides a method to tune the microstructure and therefore the mechanical properties.

In light of current environmental pressures (referring to its destruction) and the consumption of petrochemical resources, the substitution of chemicals products with renewable natural substances has attracted extensive interest. In this paper, a synergistically constructed lignin polypropylene matrix composite with long-chain branched characteristics was prepared by a pre-irradiation and melt blending method. The effects of lignin on the crystallization, rheological behavior, foaming and aging properties of polypropylene were studied. Differential scanning calorimetry and polarized light microscopy results show that lignin undergoes heterophasic nucleation in a polypropylene matrix; rheological studies show that lignin promotes the formation of a heterogeneous polypropylene network, and thus polypropylene exhibits long-chain branching features; nucleation and a network structure endow the polypropylene-based composites with uniform cell size, thin cell walls, and a foaming ratio of 5-44 times; at the same time, a large number of hindered phenols in lignin can capture free radicals to improve the aging properties of the polypropylene. This research will help to convert industrial waste into functional composite materials.

Polypropylene blends with both polybutadiene rubber (PB) and polycarboxylbuturonile rubber (xNBR) and the required amount of acrylamide (AM) was prepared by blending with water, and the crystallinity, rheological behaviour and thermal performance were analysed and compared. The results of DSC and XRD characterization showed an obvious enhancement in the crystallization of the PP matrix in PP/xNBR/AM blends compared to PP/PB/AM blends, due to the strong incompatibility between xNBR nanoparticles and the PP polymer matrix leading to the inhibition of segmental mobility and induced formation of heterogeneous nuclei. Rheological analysis showed that the dynamical mobility of polymer chains was retarded while the AM monomer was incorporated, due to strengthening interfacial interactions by grafts through hydrogen bonding. The foaming performance was clearly improved, as reflected in the uniform cell morphology and higher cell density, and the expansion ratio achieved was 13-fold. In addition, the decomposition temperature increased from 403 °C to 465 °C by nearly 62 °C as compared with neat PP, which is ascribed to the inhibition of segmental mobility due to the cyclization reaction of nitriles. The increase in the surface energy was about 2.2-fold, which resulted in a decrease of the water contact angle from 105.3° to 83.7°, attributed due to AM addition to the composition.

Much attention has been paid to the fabrication of two-dimensional (2D) nanomaterials as therapeutics for nanomedicine in recent years owing to their special physicochemical characteristics. These fascinating physicochemical properties alongside their diverse biomedical applications drive us to give a review of the present endeavors of interest in these 2D nanomaterials. In this review, the up-to-date research advances of the preparation, biocompatibility and biodegradation behaviors of 2D nanomaterials including transition-metal dichalcogenides (TMDs), transition metal oxides (TMOs), black phosphorus (BP) nanosheets, metal-organic frameworks (MOFs), 2D boron (B), boron nitride (BN), layered double hydroxides (LDHs), 2D nanoscale metals, and other kinds of 2D nanomaterials are introduced. The in vitro and in vivo bio-compatibility, including their degradation assessments from the aspects of a redox reaction, enzymes, pH, and the cell environment, etc., of the above categories of 2D nanomaterials are discussed in detail. Finally, the prospects and challenges of the development of 2D nanomaterials aiming for biomedical applications are summarized.

A novel electromagnetic functionalized Ni@PPy composite was synthesized with a cleaning method. XRD and FTIR analyses showed that the Ni@PPy composite was successfully prepared. SEM, TEM, and HRTEM results proved that Ni nanoparticles, produced by the γ-irradiation-induced reduction method, were wrapped with polypyrrole (PPy) shell to form core–shell structure. There existed many Ni cores in a PPy shell, which could induce more interfacial and dipolar polarization than the structure with one core in a shell. With an increase in Ni content, the dielectric loss was obviously decreased and the magnetic loss had little change. Attenuation constant decreased gradually, which was influenced jointly by conductivity loss and dipolar and interfacial polarization loss. When nPy/nNi/nAPS was 1.75:1:1.75, the as-prepared Ni@PPy composite exhibited the highest microwave absorption (RLmax of − 48 dB at 7 GHz and EAB of 3.8 GHz) owing to suitable impedance matching as well as attenuation ability. Therefore, such core–shell structured Ni@PPy composite would be a promising microwave absorber.

Photo-induced cancer therapies, mainly including photothermal therapy (PTT) and photodynamic therapy (PDT), have attracted numerous attentions owing to the high selectivity, convenience, and few side effects. However, single PTT usually requires high laser power density, and single PDT usually needs a high photosensitizer dosage. Herein, a kind of composite nanocarrier based on clay (laponite)-polypyrrole (LP) nanodisks was synthesized via the in situ polymerization of pyrrole in the interlayer space of laponite. LP composite nanodisks were then coated with polyvinylpyrrolidone (PVP) to form the LP-PVP (LPP) composite nanodisks which show an excellent colloidal stability and in vitro and in vivo biocompatibility. The interlayer space of LPP can be further used for the loading of Chlorin e6 (Ce6), with an ultrahigh loading capacity of about 89.2%. Furthermore, the LPP nanocarrier can enhance the PDT effect of Ce6 under the irradiation of a 660 nm laser, through enhancing its solubility and cellular uptake amount. Besides, it was found that LPP nanodisks exhibit a more outstanding photothermal performance under a 980 nm near-infrared laser (NIR) than a 808 nm NIR laser, with the photothermal conversion efficiency of 45.7 and 27.7%, respectively. The in vitro and in vivo tumor therapy results evidently confirm that the Ce6-loaded LPP nanodisks have a combined tumor PTT and PDT effect, which can significantly suppress the tumor malignant proliferation.

Laser melting deposition with WC addition has been developed to fabricate high-strength CrMnFeCoNi-based high-entropy alloys-based composites. By this technique, a microstructure of compact refined equiaxed grains can be achieved, and the tensile strength can be remarkably improved. The sample with 5 wt% WC addition shows a promising mechanical performance with a tensile strength of 800 MPa and an elongation of 37%. The improvement in mechanical property may be attributed to the formation of Cr23C6 reinforcement precipitates, which could promote the heterogeneous nucleation of grains and hinder the propagation of slip bands.

Calcined ginger nut (CGN) has been applied in grouting mortars for anchoring unstable earthen sites, but the lack of scientific research limits its application. In this study, CGN-based grouts admixed with fly ash (F), quartz sand (S), or both are evaluated. To explore the optimal mixture ratios, three types of mixing groups (five proportion gradients in each group) are established. All the grout specimens are buried and maintained outdoors, and their physical (shrinkage rate, density, elastic wave velocity, and permeability) and mechanical properties are continuously examined over 180 days. The solidification processes at different ages are simultaneously observed by means of scanning electron microscopy (SEM) images. The results indicate that the physical properties of grouts are influenced significantly by initial moisture content but then remain steady for approximately 15 days. Quartz sand can effectively reduce the shrinkage rate of grouts as well as adjust their density and permeability, and might be considered as an ideal mixing material for CGN. In the solidification process, grouts are rapidly solidified after the initial hydration reaction, and the carbonation reaction in the later stage constantly improves their mechanical strength, with physical properties kept relatively stable. SEM images show fly ash and quartz sand particles are cemented by CaCO3 crystals. Through comprehensive comparison, the grouts with the mass ratio of CGN and S at 1:1 are found to better satisfy requirements that grouts should be compatible with earthen sites.

We applied 3D-printed microwire-array (MWA) structure to boost the energy conversion efficiency of laser proton acceleration. The advanced nano-printing technique allows precise control on the spacing and geometrical size of 3D structures at 100-500 nm resolution. Under irradiation of high contrast laser pulse (15J, 35fs), the MWA target generates over 1.2×1012 protons (> 1MeV) with cut-off energies extending to 25MeV, corresponding to top-end of 8.7% energy conversion efficiency from femtosecond lasers. When comparing to flat foils the efficiency is enhanced by three times, while the cut-off energy is increased by 30-70% depending on their thicknesses. By precisely controlling the array period via 3D nano-printing, we found the dependence of proton energy/conversion-efficiency on the spacing of the MWA. The experimental trend is well reproduced by hydrodynamic and Particle-In-Cell simulations, which reveal for the first time the modulation of pre-plasma profile induced by laser diffraction within the fine structures. Optimal geometry for laser-proton acceleration is therefore strongly modified. Our work validates the use of 3D-printed micro-structures to produce high efficiency laser-driven particle sources and pointed out the new effect in optimizing the experimental conditions.

We demonstrate the temporal pedestal suppression in a Ti:sapphire chirped-pulse amplification laser system. The far-field spectral phase noise can be avoided by using a stretcher based on two concave mirrors in the system, reducing the intensity and the time range of the amplified pulse’s pedestal. At the amplified energy of 1.7 J, the contrast measurement showed that the pedestal intensity was at a level of about 1 0 − 10 within a 10 ps time window near the main pulse. In the proton acceleration experiment, a 10 nm thickness CH target was irradiated by the high-contrast pulse with the focused intensity of ∼ 1.4 × 1 0 20 W / c m 2 , which generated a proton beam with a cutoff energy of 16 MeV.

A series of Tantalum Nitride (TaN) films under a reactive direct current magnetron sputtering method with a controlled total gas flow rate were prepared on aluminum oxide substrates. To find the nitrogen flow rate, which produced the minimum sheet resistance, TaN films deposited under a nitrogen gas flow ratio of 2.5%, 5%, 10%, 15%, 20%, 25% were characterized in terms of their structural and electrical properties. The optimum total gas flow rate was 60 sccm, revealing the lowest deviation of sheet resistance. Next, the durability and reliability at high temperatures, after heating and cooling cycles and exposure to the induced current, were tested. When the nitrogen flow ratio reaches 2.5%, it gets the maximum for the adhesion force, roughness, and deposition rate of the TaN film, and maximum values are 75.4 N, 1.1 nm, and 3.67 nm/min, respectively, and the sheet resistance of the TaN film reaches a minimum of 20.32 Ω/sq. The degradation behaviors and failure of TaN films were investigated by measuring the sheet resistance variation. To further explain the degradation of TaN films, additional analysis of their crystallinity was conducted. The results showed that TaN-based thin film resistors have high durability and reliability, and are suitable for embedded passive resistors.

This work conducts computational analysis into a liquid crystal (LC) based enclosed coplanar waveguide (ECPW) phase shifter, comparing among 16 types of LC respectively at 60 GHz. Results reveal a mismatch between the patterns of the device’s figure-of-merit (FoM, the ratio of maximum differential phase shift to maximum insertion loss) and those of the LC materials’ intrinsic FoM (the ratio of tunability to dissipation factor). Noteworthy, phase shifters with GT7-29001 and MDA-03-2838 obtain the highest FoM for devices, outperforming those filled with GT5-28004 and TUD-566 claimed with the highest FoM for materials.

As bifunctional materials, phenanthrene derivatives 2,7-diphenylphenanthrene and 2,7-di(styryl)phenanthrene ( DPPa and DSPa ) were designed and studied. Both materials show charge transport properties and strong solid-state emission. The hole mobility was measured to be 1.6 and 0.4 cm2 V−1 s−1 for DPPa and DSPa , respectively. While the photoluminescence quantum yield of DPPa and DSPa was as high as 37.13% and 62.36%, respectively.

Nanoporous Au (NPG) films possess excellent and stable surface enhanced Raman scattering (SERS) activity. Sputtering followed by dealloying is one of the most used techniques to prepare NPG films. The morphology of the NPG can be controlled by changing the dealloying time, therefore tuning the SERS performance of the NPG. In the present work, Au-Ag alloy film was prepared on the Si wafer with a Cr transition layer by sputtering from a Au40Ag60 target. NPG films with tailorable average pore diameter ranging from 13 nm to 52 nm were successfully prepared by changing the dealloying time. The effect of the morphology evolution on the SERS performance of the NPG film was investigated. The dealloyed NPG film exhibits good SERS activity with a high EF of 2.4 × 105. This work provides important insights into the understanding of the correlation between the dealloying time controlled morphology and the SERS performance of the NPG films.

An asymmetric anthracene derivative (4-HDPA) was designed and synthesized. With the optimization of proper scenario of fabrication process, top-contact thin film devices based on 4-HDPA exhibit mobility as high as 3.59 cm2 V–1 s–1, while its single-crystal devices exhibit mobility as high as 5.12 cm2 V–1 s–1, which is higher than the symmetrical counterpart of 4-HDPA in both single-crystal and thin film devices.

In this paper, a laser metal deposition (LMD) process has been applied to the fabrications of CrMnFeCoNi high entropy alloys. The microstructures and mechanical properties of the CrMnFeCoNi alloys prepared using casting technique and LMD technique have been investigated. It has been found that the CrMnFeCoNi samples prepared using casting show a coarse dendritic structure. The microstructures of LMD samples contain both columnar grains and/or equiaxed grains, and the proportion of columnar grains and equiaxed grains can be adjusted by changing the laser power. Besides, the mechanical properties of LMD samples can be adjusted by changing laser power, due to columnar to equiaxed transitions (CET) that are effected by solidification mode and the heat flux direction of LMD process. It is worth to mention that the mechanical properties of the 1400 W samples produced using LMD are better than those produced by casting, which is rarely observed. Furthermore, CrMnFeCoNi alloys prepared using LMD show excellent mechanical properties at cryogenic temperatures.

In this paper, a laser melting deposition (LMD) technique has been applied to fabricate CrMnFeCoNi high entropy alloys (HEAs). The microstructures and tensile properties of CrMnFeCoNi HEAs prepared under different laser power and scanning strategies have been investigated. It has been observed that the laser power and scanning strategy have significant effects on the columnar to equiaxed transitions (CET) of the microstructure of LMD CrMnFeCoNi HEAs because of their effects on heat flux direction and the temperature gradient. Due to small molten size and rapid cooling rate in LMD process which results in a significant solute-trapping effect and thus avoids component segregation, the elements distribution of LMD samples are more homogeneous than as-cast samples. Besides, tensile properties of the LMD samples can be adjusted by changing laser power and scanning strategy, which be corresponding to the changes of microstructure.

Tungsten alloys have wide applications due to their high melting point and high density. Traditional fabrication techniques of tungsten alloys, such as liquid phase sintering, usually cause distortion and a large material waste. Laser melting deposition (LMD) additive manufacturing has been considered as a promising new technique to realize the near net forming of tungsten alloys with little heat influence. In this study, thin wall 80W-20Fe alloy samples have been prepared by using LMD. Full dense samples can be obtained when the input volume energy density is larger than 150 J/mm3. As to the microstructure, besides tungsten and iron phases, Fe7W6 intermetallics can also be observed in the prepared samples, as a result of peritectic reaction during non-equilibrium solidification. The intermetallics are distributed as Fe7W6 shells surrounding tungsten phases, or Fe7W6 fragments scattered in the iron matrix. Tungsten phases exist in two forms: the tungsten particles and the tungsten dendrites. The former are un-melted or partially melted raw tungsten powders, while the latter originate from the precipitation of supersaturated tungsten in the liquid iron. With the increasing of input energy density, more tungsten will dissolves in liquid iron, thus leading to an increased proportion of tungsten dendrites after solidification. The formations of Fe7W6 intermetallics and tungsten dendrites significantly increase the hardness and brittleness of prepared tungsten alloys.

The optoelectronic proliferation of liquid crystals based passive microwave and millimetre-wave reconfigurable technology relies not only upon low-cost micro-fabrication techniques, but also on high-fidelity yet efficient device design and simulation methodologies based on an in-depth understanding of the complex coupling between waveguiding geometries and multi-material systems through multi-physics models. While closed-form analytical solutions are not possible for multi-volume complex geometries, numerically attempting the problem is of research and development interest, in particular for gaining fundamental insights on the coupling between liquid crystals optoelectronic response and millimetre-wave interactions, hence producing guidelines for in-house code development of specific optoelectronic device prototypes without resorting to commercial off the shelf software. To this end and by way of illustration, this work proposes a novel mixed-signal dielectric-partitioning model for local polarisation and tunability analysis into a liquid crystals based shielded coplanar waveguide tunable delay line targeting applications in the 57-66 GHz band. Due to the transverse electromagnetic nature of the fully enclosed coplanar waveguide structure, the traditional two-step approach (liquid crystals’ quasi-electrostatic simulation in microscopic scale progressing to millimetre-wave simulation in macroscopic scale) could be rearranged into one single stage in terms of the molecular directors with respect to the identical electric vector field distributions. The proposed standalone and quasi-analytical model is verified by experimental measurements implemented on a 0–π tunable true-time-delay phase shifter, with a 7.94% improvement in the predicting accuracy of the effective line length required, and a huge reduction in computational costs as compared with the traditional two-step method. The proposed efficient model is envisioned to inform the development of highly efficient in silico tools with high fidelity for liquid crystals based reconfigurable applications beyond displays.

This paper presents the design, optimisation and experimental verification of a wideband impedance adapting network for a liquid crystal (LC) based electronically-tuned phase shifter device including connectors operating up to 67GHz. In contrast with conventional frequency-domain methods based on cross-sectional study assuming an infinitely long transmission line, a time-domain reflectometry (TDR) method is proposed in this work to quantify the transient impedance, and optimise the electrically-short PCB transition part between 1.85mm coaxial connectors and the tunable LC part packaged in an enclosed coplanar waveguide. The fabricated device exhibits a return loss lower than -15dB from 20MHz up to 67GHz, and a maximum insertion loss less than -5.6dB for a differential phase shift of 180°, which delivers a wideband low-loss solution for states-of-the-arts in LC-based phase shifter devices with connectors.

The negative effects of thermal cycles in the process of additive manufacture present a challenge for the control of microstructure so as to fabricate the products with improved properties compared to cast. In this work, AlCoCrFeNi2.1 eutectic high entropy alloy (EHEA) was prepared by laser metal deposition (LMD). Comparison with the cast samples, the LMD-fabricated EHEA showed significantly enhanced tensile strength (by 19.7%) and increased tensile ductility (by 56.4%). Such enhancement in mechanical properties owing to the refinement of the uniformly distributed eutectic-structure, which was composed of a ductile FCC(L12) phase and a strong BCC(B2) phase embedded with a high density of nano-precipitates. These nano-precipitates effectively pinned the dislocations, resulting strain hardening/dislocation accumulation capability. The present work provides a new strategy to utilize both the high cooling rates of LMD and the eutectic-structure characteristics for achieving homogeneous structures and superior mechanical properties to those prepared by traditional processing techniques.

Coplanar waveguide architectures combined with liquid crystals (LC) technology have been demonstrated with superior performance (i.e. less lossy than inverted microstrips and more compact than waveguides) for millimetre-wave phase-shifting applications, as evidenced by our two generations of proof-of-concept demos. In this paper, we contribute an in-depth evaluation from multiple perspectives of fabrications that aim to push the device’s performance limits beyond 60 GHz.

We designed, fabricated, and characterised novel all-optically driven passive phase shifters ($0-\pi$) at X band based on nematic liquid crystals (GT3) admixed with mesogenic azo dye (CPND7). Thanks to the functional mixture, the developed all-optical phase tuning device enables the removal of voltage-driven networks required by conventional tunable solutions. The embedded light intensity-dependent impedance matching mechanism allows the insertion loss equalisation inherently between phase delaying states, hence removing bulky amplifiers or attenuators for amplitude compensations. The highly scalable planar standalone technology is envisaged to complement the existing electronically steered phased array antenna systems targeting continuous broadband connectivity for SATCOM on the move, and holistically address the future communications demand from various sectors of the economy.

Because some asthma patients have different types of inflammatory cells in their bodies, they cannot get relief with traditional drugs. However, the nano drug delivery system can realize efficient drug delivery, inflammatory cells and intracellular targeting, and the apoptosis of inflammatory cells. This article aims to comprehensively evaluate the effects of montelukast sodium combined with graphene oxide nanomaterials on improving the clinical symptoms and airway inflammation of children with bronchial asthma, with a view to further improving the clinical treatment of children with bronchial asthma. The results show that montelukast sodium can improve lung function in patients with asthma, and also has important effects such as anti-inflammatory and regulating immune function. After exposure to graphene oxide, the level of oxidative stress in mice increased with brightness and humidity, demonstrating the role of T oxidative stress in the development of asthma. In addition, nanocarriers assist co-loaded drugs to deepen and enrich the pulmonary inflammation site, further achieving effective mitochondrial targeted drug delivery, thereby enhancing the inhibitory effect of anti-apoptotic proteins, leading to inflammatory cell apoptosis.

A laser metal deposition (LMD) process has been applied to the fabrications of the (CrMnFeCoNi)1-xFex (x = 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6) Multi-principal elements alloys (MPEAs). It is found that the LMD-fabricated (CrMnFeCoNi)50Fe50 alloy keeps a single-phase solid solution microstructure. Compared with the CrMnFeCoNi MPEA, the (CrMnFeCoNi)50Fe50 alloy obtains remarkably improved plasticity from 45% to 77%, while maintaining tensile strength (415 MPa to 470 MPa), due to the strain-induced FCC to BCC phase transformation. Furthermore, the (CrMnFeCoNi)50Fe50 alloy shows excellent mechanical properties at cryogenic temperatures. This alloy has lower cost and better mechanical property than the well-known CrMnFeCoNi MPEA by the addition of inexpensive Fe elements. The present work provides important pathways in the development of low-cost LMD-fabricated MPEA for cryogenic engineering applications.

Millimetre-wave beam-steering distortions are due mainly to unbalanced feeding amplitudes among the delay lines network. To compensate for this, active amplifiers or attenuators are employed, increasing the circuit complexity and costs, whilst compromising the passive array advantage. This work presents a passive millimetre-wave distortion-free beam steering solution with analog resolution in liquid crystal planar delay line technology. Enclosed coplanar waveguide (ECPW) tunable delay lines with 0-180˚ and 0-360˚ phase-shifting ranges are prototyped respectively. A novel impedance matching and mismatching approach for amplitude compensation is proposed and verified, as evidenced by the 67 GHz measured maximum insertion loss of –4.37 dB (variation up to 5%) for the 0-180˚ delay line, and –8.28 dB (variation up to 8%) for the 0-360˚ device. Based on a smart combination of the 0-180˚ and 0-360˚ ECPW, an optimised delay lines deployment scheme is proposed for two-dimensional beam steering with a fault tolerance capability and a minimised systematic insertion loss in total on the feeding network.

Moderator temperature coefficient (MTC) and fuel Doppler temperature coefficient (DTC) are both the key reactivity coefficients for the safety assessment of a nuclear fission reactor core. Conventional unidirectional perturbing computation exhibits a limited scope in understanding the full-core physics. To better assist the energy policy decision making, this work contributes two different perturbation approaches to characterise the temperature coefficients of reactivity, i.e. by perturbing the moderator (or fuel) temperature while keeping the core power, or by perturbing the power while keeping the moderator (or fuel) temperature. Multi-physics computational codes suite (WIMS-PANTHER-Serpent) is employed to simulate and benchmark the startup core behavior of a nuclear new build currently occurring in the UK. Reasonably good agreements with the nuclear reactor physics are demonstrated computationally for both perturbation methods.

A novel nickel-free gold-plated enclosed coplanar waveguide is experimentally demonstrated for a liquid crystal tunable delay line phase shifter at 60 GHz. By numerical investigations, we find that conventional surface impedance model (without meshing inside metals) fails to accurately characterise the effect of gold-plating thickness on conductor loss, especially when the plating thickness is smaller than 4 times of the gold's skin depth. To address this, adaptive meshing inside metals is performed for accurate modelling of the device. The gold-plating thickness is then experimentally optimised and tailored for the liquid crystal-based device-making procedures, i.e. taking into account the accelerated copper migration into gold problem during the alignment agent baking process at 200°C. Measurement results of assembled phase shifters at 60 GHz verify that a direct gold plating of 2μm on Cu can reduce the insertion loss by 1.79 dB and 2.85 dB as compared with that with a thinner plating of 50 nm, and no plating, respectively. The maximum insertion loss of -2.996 dB demonstrated at 60 GHz for the 0-π phase shifter delivers a figure-of-merit of 60°/dB, an improvement of 42°/dB as compared with up-to-date literature.

Microwave phase shifters based on tunable dielectrics such as nematic liquid crystals (NLC) have attracted considerable research attention in the last two decades. To electronically drive the permittivity variations based on the NLC’s molecular anisotropy, conventional device configuration is based on externally wiring three-port bias tees as diplexers for frequency-domain multiplexing, i.e. isolating the RF port from the low-frequency high-amplitude bias field. The multi-stage bulky solution significantly impedes its applicability for phased array feeds. To the best of the author’s knowledge, limited research has attempted the integration of compact bias tees into the phase shifter. To this end, this work demonstrates a bias-tees-embedded standalone phase shifter integrated on a double-sided RO4003 substrate using advanced fabrication and assembly techniques (photolithography, surface mounting, reflow soldering). The measured differential phase shift reports 391.75° at 10 GHz with the insertion loss up to -5.66 dB (including bias tees) for an optimised design. A figure-of-merit of 69°/dB is achieved, which even outperforms recent advances in NLC-based planar phase shifters without bias tees.

Precisely modelling burnup behavior of Gadolinia burnable poison pins in a nuclear reactor is tricky, as it is a very strong absorber of thermal neutrons. The highly self-shielded burnable poison depletes largely from outermost zones inwards, presenting strong flux gradients around the pin. Classic modelling methods are based on equivalence theory, tracking pin-averaged cross sections, and collapsing all radial rings down. However, the subdivision of the whole pin into multiple radial zones is ineffective, as each zone is still represented by the same cross sections in 172 groups. To capture the self-shielding effect, a subgroup method is employed in this work to accurately account for the ring effect in Gadolinia-bearing pins. Deterministic code (WIMS) is used for producing homogenised cross sections for Gadolinia-zoning assemblies, obtaining lattice power distributions, the results of which are benchmarked against a Monte Carlo code (Serpent) for model verifications.

Understanding the role of TiO2 in glass structure is the key to the development of new functional glass materials. In this work, the changes in the structural units of SiO2-TiO2-ZrO2-RO-Al2O3 (R=Ca, Sr, Ba) multicomponent glass were characterized by X-ray photoelectron spectroscopy, magic angular spinning nuclear magnetic resonance and Raman spectra. It is determined that with increasing TiO2/SiO2 molar ratio, the amount of [TiO4] and [TiO6] increase at the expense of [TiO5] and the coordination of Al3+ changes little. Si4+is mainly linked in the Q3 and its proportion is related to the change of TiO2 content, which infers that the nonbridging oxygen number, the proportion of Si-O-Ti, Ti-O-Ti and Si-O-Si also varies accordingly. The changes in structure also affect the performance of the glass. The results indicate that the substitution of TiO2 increases the density and dielectric constant of the glass, makes the glass thermal stability decrease slightly. This work provides a basis for the performance tailoring of high dielectric glass fiber.

The negative effects of thermal cycles in the process of additive manufacture present a challenge for the control of microstructure so as to fabricate the products with improved properties compared with conventional casting technique. In this work, AlCoCrFeNi2.1 eutectic high-entropy alloy (EHEA) was prepared by laser metal deposition (LMD). Compared with conventionally cast EHEA samples, the LMD-fabricated EHEA samples showed significantly enhanced tensile strength (by 19.7%) and increased tensile ductility (by 56.4%). Such enhancement in tensile properties was attributed to the refinement of the uniformly distributed eutectic-structure, which improved the strain hardening/dislocation accumulation capability of the EHEA. The present work provides a new strategy to utilize both the high cooling rates of LMD and the eutectic-structure characteristics for forming refined homogeneous structures and thus achieving superior mechanical properties to those prepared by traditional processing techniques.

We present a comprehensive study of the electrochemical capacitance between a one-dimensional electronic material and an electrolyte. In contrast to a conventional, planar electrode, the nanoscale dimension of the electrode (with diameter smaller than the Debye length and approaching the size of the ions in solution) qualitatively changes the capacitance, which we measure and model herein. Furthermore, the finite density of states in these low dimensional electronic systems results in a quantum capacitance, which is comparable to the electrochemical capacitance. Using electrochemical impedance spectroscopy (EIS), we measure the ensemble average, complex, frequency dependent impedance (from 0.1 Hz to 1 MHz) between a purified (99.9%) semiconducting nanotube network and an aqueous electrolyte (KCl) at different concentrations between 10 mM and 1 M. The potential dependence of the capacitance is convoluted with the potential dependence of the in-plane conductance of the nanotube network, which we model using a transmission-line model to account for the frequency dependent in-plane impedance as well as the total interfacial impedance between the network and the electrolyte. The ionic strength dependence of the capacitance is expected to have a root cause from the double layer capacitance, which we model using a modified Poisson-Boltzmann equation. The relative contributions from those two capacitances can be quantitatively decoupled. We find a total capacitance per tube of 0.67-1.13 fF/μm according to liquid gate potential varying from -0.5 to -0.7 V.

Metallic ordered porous structures have attracted increasing attention due to their wide range of applications, but their preparation is usually accompanied with the employing of consumable templates. The development of template-free method to prepare metallic ordered porous structure can significantly reduce the cost as well as streamline the procedures. In the present work, a new template-free method of additive manufacturing combined with etching was proposed to prepare ordered porous structures. (Cu, Ni) honeycomb structure with pore size of ~11 μm and wall thickness of ~200 nm was successfully prepared from the Fe-Cu-Ni precursor alloy. The morphology evolution and the potential formation mechanism of the (Cu, Ni) honeycomb structure were studied. This work provides important insights into the preparation of ordered metallic porous structure without template.

A laser melting deposition (LMD) technique has been applied to fabricate thin wall V-5Cr-5Ti samples. By applying a scanning speed of 400 mm/min, laser powers of 1200W, 1400W, 1600W, and 1800W, and scanning strategies of single directional scanning and dual directional scanning, full dense thin wall samples have been successfully prepared. Microstructures at the bottom region of walls mainly consist of coarse columnar grains, showing a 〈100〉 fiber texture. Microstructures in the middle and at the top regions of walls mainly consist of fine columnar grains or equiaxed grains, showing random textures. Columnar dendritic growth takes place for columnar grains. The columnar dendrites grow epitaxially from parent grains, following one [100] axis closest to the heat flux direction. However, the integral growth directions of columnar grains are opposite to the heat flux direction. Including a small deviation of one [100] axis from heat flux direction, the growth space of columnar dendrites also counts for the success in competitive growth for columnar grains. Deposition height, laser power, and scanning strategy show significant effects on the grain structure evolutions of thin wall samples, due to their effects on the temperature gradient. As the deposition height increases, columnar to equiaxed transitions (CETs) have been observed for all samples. The CETs happen faster for higher laser power, and for dual directional scanning compared to single directional scanning. Due to the differences in local composition caused by microsegregation, clusters containing lath-like precipitates are observed to delineate the dendrites. The effects of processing parameters on microstructures can be represented by a metric of volumetric energy density. A decrease of energy density will lead to CETs.

In this work, we synthesized a series of microcrystalline MnxN100−x-MOF-74 (N = Fe, Co and Ni) materials by a one-pot reaction. Powder X-ray diffraction (PXRD) patterns of MnxN100−x-MOF-74 matched well with those of single-metal MOF-74, and the scanning electron microscopy (SEM) images exhibited homogeneous nanocrystallites aggregated together. The amounts and dispersion of metals were analyzed by using inductively coupled plasma (ICP) and energy-dispersive X-ray spectroscopy (EDS), separately. MnxN100−x-MOF-74 could remain crystalline and efficiently catalyze the epoxidation of alkenes in DMF with NaHCO3 and 30% H2O2. In particular, Mn29.39Fe70.61-MOF-74 can achieve almost 100% conversion for styrene with 95.0% selectivity towards styrene oxide and be reused at least five times without loss of activity.

Two new anthracene derivatives were designed and synthesized. Ant-Th-Ph and Ant-ThPh show high single crystal mobilities of 1.1 cm2 V−1 s−1 and 4.7 cm2 V−1 s−1. Moreover, strong solid state emission was determined to be 36.52% and 33.32% for Ant-Th-Ph and Ant-ThPh respectively.