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Summary Although advances in coating technologies have allowed us to match—or even exceed—the lubricity of Nature’s low-friction surfaces, the performance of synthetic materials inevitably diminishes over time as the surfaces are worn and damaged by irreversible breakage of covalent bonds. Synthetic systems lack the bespoke repair mechanisms that replenish hydration lubrication surfaces in Nature. Here, we demonstrate dynamic repair of low-friction surfaces prepared through a surface-selective self-assembly strategy. Monolayers of lubricating polymers associate with functionalized surfaces through strong and specific host–guest interactions, leading to hydration lubrication surfaces with low coefficients of friction (0.024–0.028). Following friction-induced dissociation of the polymers, the polymer-to-surface interaction is restored by the reformation of host–guest complexes, thus repairing the monolayer, renewing the lubricity, and reducing the effects of wear. Such dynamically restored low-friction materials will be an essential tool in decreasing global energy use—a fifth of which is expended overcoming friction.

III-nitride quantum dot (QD) lasers have potential applications in visible light regime, yet one of its most important dynamic parameters, the linewidth enhancement factor (LEF), has been rarely studied. We studied the LEF of InGaN QD lasers with a comprehensive theory model and found that the LEF values of InGaN QD lasers can be smaller and more robust against inhomogeneous broadening than those of InGaAs QD lasers. In addition, the LEF improvement from quantum well to QD in III-nitride semiconductors is much larger than that in III-arsenide. It is believed that the large confinement energy in III-nitrides and atomic-like density of states of QDs contribute to these advantages of III-nitride QD lasers. Our results not only reveal the advantages of using III-nitride QD for high spectral purity, low-chirp laser applications, but also provide a general guideline for designing QD lasers with lower LEF values in various semiconductor materials.

We present a vertically aligned multiwall carbon nanotube (VA-MWCNT) based humidity sensor with low cost and simple fabrication method compatible with mass production. The VA-MWCNT is well aligned and possesses an interconnect topography. Initially, the VA-MWCNT showed superhydrophobic characteristics, which are not suitable for humidity sensing. Therefore, to protect the topography of the material and make the surface more hydrophilic, a low cost and easy handling treatment method was adopted with O2 plasma surface functionalization. The fabricated device showed good linearity at the range of 40% RH–90% RH, low hysteresis ( H = 1.5%RH), fast response (3.3 s), high stability ( Cv Rr _max 0.6% ), demonstrating excellent performance in both static and dynamic measurements. The high performance and low-cost fabrication methods make the VA-MWCNT-based sensor a promising candidate for the application of humidity sensing. Moreover, benefiting from the simple fabrication process, it can be easily extended to resistive sensing fusion with the integration of the temperature sensor and flow sensor for more complex applications.

Water-based fracturing fluids are widely used in hydraulic fracturing to stimulate reservoirs. However, a novel fracturing fluid system needs to be developed for use in complex and challenging envi...

The superlubrication property of articular cartilage is attributed to the hydration lubrication mechanism. This involves the complexation of biomacromolecules with phosphatidylcholine lipids to form a lubricating boundary layer on the surface. Based on this mechanism, a branched polyelectrolyte polymer – PEI-PMPC was synthesised in this study to enhance lubrication via tert-butyl hydroperoxide-initiated grafting polymerisation of 2-methacryloyloxyethyl phosphorylcholine (MPC) onto polyethyleneimine (PEI) with various molecular weights. Following the characterisation of the polymer using nuclear magnetic resonance, a series of tribological tests were performed under different normal loads and different scan rates. The results showed that the PEI-PMPC polyelectrolyte polymer in aqueous solution could effectively reduce the friction coefficient and wear generation between the polyethylene ball and the silica wafer. Additionally, an improvement in the lubrication performance was detected for the PEI-PMPC polyelectrolyte polymer when high molecular weight PEI was used during the reaction, which was attributed to the formation of the hydration shells surrounding the zwitterionic charges of PMPC and the viscosity of the polymer. In conclusion, the PEI-PMPC polyelectrolyte polymer developed herein was characterised by enhanced lubrication, and may be potentially used for biomedical applications such as intra-articular injection to restore joint lubrication.

The optimal soaking time and nanosilica concentration were chosen by the physical properties of the nanosilica-modified recycled aggregate. Recycled aggregate concrete (RAC) and nanosilica recycled aggregate concrete (SRAC) were fabricated by using ordinary recycled aggregate and nanosilica-modified recycled aggregate. Based on the comparative experimental study of basic mechanical properties, the effects of nanosilica recycled aggregate(SRA) modification and recycled aggregate(RA) replacement percentage on the basic mechanical properties of recycled concrete were analyzed. Finally, the split-Hopkinson pressure bar (SHPB) was used to conduct comparative experimental research on the impact resistance of recycled aggregate concrete and nanosilica-modified recycled aggregate concrete. The effects of nanosilica recycled aggregate modification and aggregate replacement percentage on failure morphology, dynamic peak stress, dynamic increase factor (DIF), dynamic peak strain were analyzed.

Monolayer (ML)-scale GaN/AlN multiple quantum well (MQW) structures for electron-beam-pumped ultraviolet (UV) emitters are grown on c-sapphire substrates by using plasma-assisted molecular beam epitaxy under controllable metal-rich conditions, which provides the spiral growth of densely packed atomically smooth hillocks without metal droplets. These structures have ML-stepped terrace-like surface topology in the entire QW thickness range from 0.75–7 ML and absence of stress at the well thickness below 2 ML. Satisfactory quantum confinement and mitigating the quantum-confined Stark effect in the stress-free MQW structures enable one to achieve the relatively bright UV cathodoluminescence with a narrow-line (~15 nm) in the sub-250-nm spectral range. The structures with many QWs (up to 400) exhibit the output optical power of ~1 W at 240 nm, when pumped by a standard thermionic-cathode (LaB6) electron gun at an electron energy of 20 keV and a current of 65 mA. This power is increased up to 11.8 W at an average excitation energy of 5 µJ per pulse, generated by the electron gun with a ferroelectric plasma cathode at an electron-beam energy of 12.5 keV and a current of 450 mA.

Present study aims to investigate the effect of nanoparticles (zein nanoparticles, nanocellulose, nano-TiO2, nano-SiO2) incorporation on rheological properties of film-forming solutions and physicochemical properties of konjac glucomannan (KGM) based films, and to evaluate the effect of KGM/nanoparticles blend film on cherry tomatoes preservation. The results showed that the blend film-forming solutions exhibited shear-thinning behavior, and KGM/zein nanoparticle film-forming solution showed the lowest crossover frequency value of storage (G′) and loss (G") moduli due to enhanced molecular interaction and entanglement. The nanoparticles were dispersed homogeneously in the KGM continuous matrix and had good compatibility with KGM, thereby improving physicochemical properties of KGM based films. KGM/zein nanoparticle blend film (KNZ) showed the best properties, such as smoother surface and denser cross-section, the highest glass transition temperature and elongation at break, as well as the best moisture and oxygen barrier. In comparison with the control and polyethylene film packaging, cherry tomatoes in KNZ film packaging showed lower weight loss and firmness reduction, and had relatively stable content of total soluble solids, vitamin C content and pH value during storage up to 10 days at 26 °C. The results suggested the high potential of KNZ film for application in cherry tomatoes preservation.

Bacteria are one of the main groups of organisms, which dynamically and closely participate in human health and disease development. With the integration of chemical biotechnology, bacteria have been utilized as an emerging delivery system for various biomedical applications. Given the unique features of bacteria such as their intrinsic biocompatibility and motility, bacteria-based delivery systems have drawn wide interest in the diagnosis and treatment of various diseases, including cancer, infectious diseases, kidney failure, and hyperammonemia. Notably, at the interface of chemical biotechnology and bacteria, many research opportunities have been initiated, opening a promising frontier in biomedical application. Herein, the current synergy of chemical biotechnology and bacteria, the design principles for bacteria-based delivery systems, the microbial modulation, and the clinical translation are reviewed, with a special focus on the emerging advances in diagnosis and therapy.

Given that many people suffer from extensive skin damage, wound repair has drawn tremendous attention in research. Among the various assistant dressing materials that promote healing, a porcine acellular dermal matrix (PADM), as a skin substitute, can efficiently accelerate healing by promoting cell migration and proliferation. However, a simple, low-cost preparation process remains a challenge facing PADM development, particularly because of the inferior elasticity. To overcome these drawbacks, a CaCl2-ethanol-H2O solution (ternary solution) combined with an additional enzyme treatment was used to obtain a transparent, porous, and elastic PADM that retained the major extracellular matrix composition of the dermis. Our results indicated that alterations in the fiber organization and secondary structural changes in the collagen occurred after treatment. Furthermore, the in vivo wound healing and histological analyses clearly revealed an extremely expedited wound repair process following the application of the biocompatible PADM. In conclusion, this study provides new insights into the development of a transparent PADM with a porous structure and good elasticity that can be used as a skin substitute to accelerate the wound healing process. Moreover, this effective technique could potentially be used to extrapolate other decellularized materials in the future.

In this paper, a magnetic core–shell composite with MgNi2FeO4.5 nanotubes as core and carbon nanotubes (CNTs) as shell was synthesized by in situ growth of CNTs on the surface of MgNi2FeO4.5 nanotubes via a catalytic chemical vapor deposition method. The MgNi2FeO4.5 nanotubes were prepared using a mixed aqueous solution of Mg(NO3)2, Ni(NO3)2 and Fe(NO3)3 (molar ratio of 1:2:1) and anodic aluminum oxide as template. Both the growth temperature and time of CNTs brought about effect on the structure and magnetic property of the composite were investigated. X-ray diffraction, transmission electron microscope, field emission scanning electron microscope, Raman spectroscopy and vibrating sample magnetometer were used to characterize the as-prepared samples. The MgNi2FeO4.5 nanotubes are parallel arranged, and the exterior surface of which is wrapped by CNTs when the growth temperature exceeding 480 °C. Magnetic measurement demonstrates the composite with higher growth temperature and shorter growth time possesses more excellent magnetic property.

In this study, we performed a 3D organotypic culture of human lung fibroblast (HLF) in a microfluidic device. This 3D HLF model could partly simulate the biological responses of human lung....

A rational solvothermal method is proposed to achieve the conversion from a Zn contented metal organic framework to ZnO mesoporous single-crystal-like spheres. The as-prepared ZnO sphere is composed of oriented assembled primary crystals, which exhibits single crystal nature with narrow pore size distribution and high surface area. In addition, time depending trails indicate the metal organic framework functions as reservoir to control the release of Zn species and the organic molecules also serve as directing regent to facilitate the oriented assembling of the ZnO primary units. Thanks to this structure coherence, the ZnO sphere delivers high electron mobility, which enables reduced carrier recombination and improved collection efficiency of the photoelectrons when used as photoanode in CdS/CdSe sensitized solar cell. The device achieves a high power conversion efficiency of ∼6.20%, which is substantially improved from that of regular ZnO nanoparticles (∼5.02%). Moreover, when evaluated as anode for lithium ion battery, the ZnO sphere based electrode demonstrates high reversible capacity of 1016.7 mA h g−1 at 100 mA g−1 after 100 cycles, and excellent high rate stability which shows impressive reversible capacity of 698.4 mA h g−1 at 1000 mA g−1 after 300 cycles.

Fiber Bragg Grating (FBG) sensors need to be mounted at the outer surface of any metallic test piece to monitor its structural integrity through measuring physical quantities, such as strain, pressure, vibration, and temperature. High-temperature epoxies or ceramic epoxies are used to mount the said sensors to operate under high-temperature environment conditions. The unsteadiness of the outer surface of the metallic piece and non-uniformity of the applied epoxy over the sensing head, affect its operation and measurement accuracy in the long run. Here, in the first part of a twopart article, we have investigated the reliable functioning and spectrum evolution of the FBG sensors, mounted on a carbonsteel tube, for temperature up to 500° C. Polyimide coated femtosecond laser written FBG sensors are surface mounted on the said tube using a high-temperature adhesive. There is no peak splitting, and chirp phenomenon experienced by the sensors at the end of two thermal cycles. The second part of the two-part article focuses on the mounting and operation of gold-coated FBG sensors in the high-temperature operating environment.

Core-shell structural capsules can encapsulate various food ingredients (e.g., nutrients), thus being highly potential for the design of many food products. This work reports how the gum (xanthan, locust bean or gellan) inclusion tailors the practical features of agar/konjac glucomannan (KGM) system for fabricating the core-shell structural capsules. The rheological and textural analyses revealed that xanthan gum inclusion could simultaneously increase the sol-gel transition point and gel strength (ca. 1.6 times higher) of agar/KGM system. The composite gels were dehydrated to generate shell materials. The materials including xanthan or locust bean gum showed stronger chain interactions than did that including gellan gum, accompanied by weakened crystalline features for the different shell materials. Again, compared to the agar/KGM counterpart, the shell materials including xanthan gum could display a similar tensile strength (close to 50 MPa) but an evidently increased elongation at break (ca. 2.5 times higher). Then, these agar/KGM based systems were used to prepare core-shell structural capsules. The capsules based on agar/KGM/xanthan gum materials exhibited the highest roundness and breaking stress. Regarding this, the increased sol-gel point reduced the time required for droplet hardening (to generate core-shell gel balls); such fact, together with the higher gel strength, weakened the deformation of gel balls and thus increased the roundness and breaking stress of capsules (resulting from drying of gel balls).

In this study, 3-aminopropyltriethoxysilane (APTES) and octyltriethoxysilane (OTES) reacted with nano-silica (NS), and the hydrophobicity, wettability and oil displacement performance of the modified nanoparticles (OAS) were changed by adjusting the amount of OTES. The synthesized amphiphilic silica was characterized by elemental analysis, flourier transform infrared spectrometer (FT-IR), thermogravimetric analysis (TG) and transmission electron microscopy (TEM). The results showed that the modification of silica was successful and showed different changes with the increase of the amount of modifier OTES. Besides, zeta potential, particle size measurement and transmission electron microscopy results show that OAS particles can maintain good stability. OAS-3 particles can change the core wettability from oil wet to neutral wet, and can significantly reduce the interfacial tension, which reduce the interfacial tension from 14.9 mN/m to 10.4 mN/m. In addition, the OAS particles also have a good emulsification effect, which can keep the emulsion stable for a long time. In the core flooding experiment, the modified amphiphilic silica particles can improve oil recovery. Compared with NS, OAS-3 particles have the best oil displacement effect, and the oil recovery can be increased by 10.3%. which has a certain potential in the application of enhanced oil recovery.

The ExoMol database aims to provide comprehensive molecular line lists for exoplanetary and other hot atmospheres. The data are expanded by inclusion of empirically derived line lists taken from the literature for a series of diatomic molecules, namely CH, NH, OH, AlCl, AlF, OH + , CaF, MgF, KF, NaF, LiCl, LiF, MgH, TiH, CrH, FeH, C 2 , CP, CN, CaH, and triplet N 2 . Generally, these line lists are constructed from measured spectra using a combination of effective rotational Hamiltonian models for the line positions and ab initio (transition) dipole moments to provide intensities. This work results in the inclusion of 22 new molecules (36 new isotopologues) in the ExoMol database.

Molybdenum sulfide/reduced graphene oxide (MoS2/RGO) porous film was in-situ deposited on fluorine-doped tin oxide (FTO) substrates via a one-pot hydrothermal method. Due to the oxygen-containing groups distributing on graphene oxide (GO) surface, the MoS2 sheets could nucleate and grow taking GO as substrates and the MoS2/RGO film can be strongly linked to the FTO. Based on the electrochemical investigations, the enhanced cell performance could be ascribed to the improved electrical conductivity, catalytic active sites and electrolyte diffusion rate, which finally contribute to the high catalytic performance on the reduction of I−/I3− couples in the electrolyte. Therefore, the cell adopting as-prepared MoS2/RGO as counter electrode demonstrated high power conversion efficiencies (PCE) of 7.63%, which indicates ∼14% enhancement compared with the MoS2-based (6.68%) device.

DNA has become an attractive medium for long-term data archiving due to its extremely high storage density and longevity. Short single-stranded DNAs, called oligonucleotides (oligos), have been designed and synthesized to store digital data. Previous works designed the oligos with a pair of primer binding sites (PBSs) (each with a length of around 200) attached at the two ends of each basic readable data block. The addition of PBSs decreases the data density significantly because in the current DNA synthesis, the maximum length of a synthesized oligo in good quality is around 200. Furthermore, the maximum homopolymer run allowed by the existing experiments has been reported to be three nucleotides. In this work, to increase the data density, we have devised and tested an oligo design for DNA-based storage with the basic readable data block appended by a single PBS at one end only, while allowing the maximum homopolymer run to be increased to 4. We also present an oligo assembly algorithm that can reconstruct oligos with a single PBS from the error-prone raw readouts obtained from the sequencing process. We have conducted a wet lab experiment to validate the proposed design, where we tested with 398KB of data stored into 10,750 oligos. The experimental results show that it is possible to recover over 99 percent of the oligo sequences without error, which proves that one PBS is sufficient for implementing a DNA-based data storage system with maximum homopolymer run relaxed to 4. The use of single PBS leads to a significant data density gain from 14.3 to 140.2 percent over the existing short-strand DNA data storage schemes by reserving more nucleotides for storing information bits.

Effect of indium (In) droplets on InGaN thin films grown by molecular beam epitaxy (MBE) has been investigated. The surface of InGaN covered by In droplets shows a smoother topography than that without droplets, indicating that the presence of In droplets is beneficial to the two dimensional growth. Beneath the In droplets, many ring-like structures are observed. The arrangement of these “ring” shows the movement of the In droplets during the InGaN growth. A qualitative growth model is proposed to explain the evolution of the InGaN surface morphology in In-droplet-induced-epitaxy process, giving an explanation that a local vapor-liquid-solid (VLS) system is preferentially formed at the edge of the droplets, leading to a high growth rate. Furthermore, the energy dispersive X-ray spectroscopy results reveal that the relatively higher In/Ga flux ratio in the region covered by the In droplet results in a locally higher In content.

An in situ hydrothermal method is employed to vertically grow Few-layer MoS2 (3–5 layers) sheets on three dimensional graphene. Oxygen atoms are spontaneously incorporated into the MoS2 layers due to the inert Mo O bonds from the precursor and the abundant oxygen-content groups distributed on the graphene oxide sheets, which reduces the bandgap and improves the conductivity and catalyzing activity of the MoS2. In addition, the three dimensional composite exhibits good mechanical strength, interconnected electron transfer network, high surface area of 117.9 cm2 g−1, and multi-level porous structures from micro- to macro- scale, which enhances the charge and mass transport when used as counter electrode for quantum dot sensitized solar cells. Therefore, an optimized power conversion efficiency of 4.13% is demonstrated, indicating ∼63% and ∼34% enhancement compared with Pt and pure MoS2 counter electrodes.

Diblock copolymer nano-assemblies of poly(2-hydroxypropyl methacrylate-b-benzyl methacrylate) (PHPMA-b-PBzMA) were synthesized by initiators for continuous activator regeneration atom transfer radical polymerization (ICAR ATRP) using the CuIIBr2/tris(pyridin-2-ylmethyl)-amine (TPMA) complex as a catalyst under dispersion conditions and were compared with those obtained by RAFT dispersion polymerization. It is found that these two kinds of polymerizations afford good control, as indicated by the linearly increasing molecular weight with monomer conversion and the narrow molecular weight distribution, whereas the ICAR ATRP runs a little faster than RAFT. In the two cases of dispersion polymerization, the morphologies of the PHPMA-b-PBzMA nano-assemblies are similar to each other and change from spheres to wormlike aggregates with block extension, whereas the size of the nano-assemblies by ICAR ATRP is usually larger than those obtained by RAFT. The degree of polymerization (DP) of the poly(2-hydroxypropyl methacrylate) and poly(benzyl methacrylate) blocks affecting the size and/or morphology of the PHPMA-b-PBzMA nano-assemblies is investigated, and the reason for the larger size of the PHPMA-b-PBzMA nano-assemblies by ICAR ATRP is discussed.

The konjac glucomannan (KGM)-based aerogel as an air filtration material was fabricated through sol-gel and freeze-drying methods. Results showed that gelatin and starch addition could increase the filtration efficiency and compressive strength of aerogel significantly, due to the appearance of more microporous structure and the formation of dense structure in aerogel. The addition of wheat straw could decrease the filtration resistance and increase the breathability of KGM-based aerogel, which was attributed to the multi-cavities of wheat straw. The aerogel with wheat straw had a filtration efficiency of 93.54% for particle matters ≥ 0.3 μm, a filtration resistance 29 Pa, and an air permeability 271.42 L/s·m2. Okara addition could increase the hydrophobicity of KGM-based aerogel by increasing the water contact angle and decreasing the equilibrium water content. The water contact angle of the aerogel containing okara reached 105.4°, and the equilibrium water content was decreased by 17.03%–81.10% compared with that without okara, with relative humidity 0%–80%. The results demonstrated that the KGM-based aerogel had good performance on filtration, mechanical and hydrophobic properties, indicating high potential application as an air filtration material.

This study presents the preparation and property characterization of a konjac glucomannan (KGM)/starch based aerogel as a thermal insulation material. Wheat straw powders (a kind of agricultural waste) and starch are used to enhance aerogel physical properties such as mechanical strength and pore size distribution. Aerogel samples were made using environmentally friendly sol–gel and freeze drying methods. Results show that starch addition could strengthen the mechanical strength of aerogel significantly, and wheat straw addition could decrease aerogel pore size due to its special micron-cavity structure, with appropriate gelatin addition as the stabilizer. The aerogel formula was optimized to achieve lowest thermal conductivity and good thermal stability. Within the experimental range, aerogel with the optimized formula had a thermal conductivity 0.04641 Wm−1 K−1, a compression modulus 67.5 kPa and an elasticity 0.27. The results demonstrate the high potential of KGM/starch based aerogels enhanced with wheat straw for application in thermal insulation.

AlGaN-based ultraviolet (UV) light sources have recently attracted much research interest due to their potential candidate to replace excimer and mercury lamps. However, their output power is limited by the inefficient p-type doping at high Al composition AlGaN. In this talk, we will report on the electron-beam-pumped UV light sources, where multiple ultrathinGaN wells are used to enhance the internal quantum efficiency and to reach deep UV range such as 230 nm. And UV light source with wavelength varing from 285-232 nm with corresponded output power of 23-160 mW have been achieved under pulse mode.

Conventional thermosets consisting of polymer networks with robust and irreversible chemical linkages are incapable of reshaping or reprocessing once formed. In contrast, reversible non-covalent crosslinks can impart structurally flexible and reconfigurable feature to the networks, but at the expense of certain mechanical strength. The integration of fixed covalent bonds and noncovalent bonds into these materials can usually attain enhanced mechanical properties and meanwhile provide dynamic and adaptable functions, such as responsive and healing ability to external stimuli. Here a double-cross-linked frustrated Lewis pair network (FLPN) is developed through a specific three-component reaction among triarylborane, triarylphosphine, and CO2 , which is composed of permanent chemical crosslinks and dynamic CO2 gas-bridged connections. The amount of CO2 added can regulate the density of supramolecular node in such FLPN, so as to control the strength and toughness of the gel material. Moreover, the broken gel can be rapidly healed by CO2 stimulus through the reconstruction of dynamic covalent network. This study will inspire a new way to create gas-based smart materials by incorporating frustrated Lewis pair chemistry into traditional gel system.

Although various inorganic particles have been confirmed as effective trappers to restrict the shuttle effect of lithium polysulfides (LiPSs) in lithium-sulfur batteries (LSB), the further reduction of LiPSs is impeded due to their low conductivity. This process results in sluggish redox kinetics at the interface of cathode/electrolyte and escaped LiPSs to electrolytes during long-term cycling. Herein, by advantageous functional integration of immobilization and conversion capability for LiPSs, a 3D aerogel with the composition of Co@CoO@N-doped carbon@graphene (Co@CoO@N-C/rGO) is designed and prepared. The dual-shells of N-C and polar CoO enable the strong chemical adsorption towards LiPSs through pyridinic – N-Li-bond and Co···S coordination, respectively. And the conductive Co core acts as a “scissor”, which catalyzes the transformation of adsorbed LiPSs into low-order ones, thus accelerating the kinetics of the liquid–solid nucleation and growth of Li2S. Moreover, the matrix of rGO serves as electrical networks, significantly promoting the transfer of electrons to the redox-active sites. Based on these synergetic effects, the LSB using Co@CoO@N-C/rGO modified separators exhibits outstanding electrochemical performance. For example, even at a rate of 1C, the cell still delivers a stable capacity of 555.4 mAh g−1 after 500 cycles for a pure sulfur electrode. Moreover, the relevant kinetic mechanisms including in situ Raman test are expounded in detail.

The world‐wide spreading of coronavirus disease (COVID‐19) has greatly shaken human society, thus effective and fast‐speed methods of non‐daily‐life‐disturbance sterilization have become extremely significant. In this work, by fully benefitting from high‐quality AlN template (with threading dislocation density as low as ≈6×108 cm−2) as well as outstanding deep ultraviolet (UVC‐less than 280 nm) light‐emitting diodes (LEDs) structure design and epitaxy optimization, high power UVC LEDs and ultra‐high‐power sterilization irradiation source are achieved. Moreover, for the first time, a result in which a fast and complete elimination of SARS‐CoV‐2 (the virus causes COVID‐19) within only 1 s is achieved by the nearly whole industry‐chain‐covered product. These results advance the promising potential in UVC‐LED disinfection particularly in the shadow of COVID‐19., The complete elimination of SARS‐CoV‐2 within 1 s by a high‐power UVC light source is demonstrated. Such an effective sterilization benefits from the well‐crystallized AlN on NPSS and the high‐power UV light source with a typical output power of 2 W at an emission wavelength of 275 nm.

We demonstrate the growth of full-composition-graded InxGa1−xN (0 ≤ x ≤ 1) on a GaN/sapphire template using plasma-assisted molecular beam epitaxy. Composition of indium in InxGa1−xN films is controlled by growth temperature and gallium flux. It was found that In composition increases gradually from x = 0 (GaN) to x = 1 (InN) along the growth direction accompanied by a gradual strain relaxation. At the initial stage of growth, multiple quantum wells like structures with low and high In composition InxGa1−xN layers are spontaneously formed, effectively relaxing the in-plane strain. Finally, the graded InxGa1−xN film exhibits a broadband absorption covering the full solar spectrum, which provides a promising path for the design and production of graded InxGa1−xN based photovoltaic devices.

Polyaniline/Perylene diimide organic heterojunction photocatalyst with three-dimensional structure (3D PANI/PDI) has been successfully prepared via an in-situ growth process. 3D PANI/PDI exhibited efficient performance in the degradation of tetracycline (TC) under visible light irradiation. The degradation rate of TC by 3D 20%-PANI/PDI is 15.3 times and 17.0 times that of pure PDI and PANI in static system, respectively. Moreover, 3D PDI/PANI showed outstanding stability and could continuously degrade TC for up to 75 h in a dynamic system. The enhanced photocatalytic performance and stability of 3D PANI/PDI mainly comes from the following three aspects: (i) The introduction of PANI polymer backbone reinforced the strength of the PDI hydrogel, thereby improved the catalytic stability of the system; (ii) The three-dimensional network structure provided more reactive sites and medium transport channels; (iii) Larger delocalized π-electron conjugated system and energy-matched heterojunction structure were established through π-π interactions between PANI and PDI, which improved the efficiency of the migration and separation of photo-generated carriers. Finally, the mechanism and mineralization pathways of TC were systematically studied. Superoxide radical ( O2−), hydrogen peroxide (H2O2) and hole (h+) were the main reactive species (RSs) for the degradation of TC. Under the attack of RSs, the TC under hydroxylation, dealkylation, aromatization, and ring-opening processes, eventually leading to complete mineralization. This work provides a new promising approach for improving the photocatalytic performance of organic catalysts and indicates that 3D PANI/PDI organic heterojunction photocatalyst can be efficiently applied for the water environmental remediation.

Uncontrolled bleeding, such as deep, narrow or irregular wound hemorrhage, has been a major cause of death in peacetime and wartime. Besides, traditional hemostatic agents are lack of antibacterial properties, which could not provide effective protection on open wound. In this paper, a novel antibacterial hemostatic agent composed of mesostructured cellular silica foams (MCF) decorated with silver ions (MCF-Ag) was synthesized by hydrothermal method. Hemorrhage wound infected with Escherichia coli was applied to evaluate its antibacterial and hemostatic performance both in vitro and in vivo. Both MCF and MCF-Ag showed excellent hemostasis in vitro and in vivo. The MCF-Ag demonstrated significant antibacterial effect. By contrast, no obvious antibacterial effect was observed from the MCF. The above results demonstrate that the MCF-Ag is an excellent antibacterial hemostatic agent with splendid water absorption and antibacterial capacity.

The light guidance characteristics of the fully and partially ethanol-filled photonic bandgap fibers (PBFs) are investigated and their applications as modal interferometers (MIs) for temperature sensing are demonstrated. Different from the ethanol-filled solid core photonic crystal fibers (PCFs), the ethanol-filled PBFs are much easier to excite more high order cladding modes, and the effective refractive index difference between the interference modes can reach 26.6 times bigger than that of the ethanol-filled solid core PCF. Without using special splicing techniques, just splicing a short section of the fully or partially ethanol-filled PBF between the single mode fibers, a PBG-based MI can be constructed with a high thermal sensitivity. Moreover, the thermal sensitivity can be adjusted within a large range by selectively filling the air core and/or air claddings of the PBF with ethanol. Experimental results show that the fully ethanol-filled PBF-based MI has the thermal sensitivity up to –292 pm/°C while that of the partially ethanol-filled PBF-based MI is changed to –120 pm/°C. They are 43.8 and 18 times bigger than that of the unfilled PBF-based MI.

We propose and demonstrate a novel plasmonic nanopore platform based on a bowtie-nanopore structure, for single-molecule sensing. In this nano-structure, nano-bowties are integrated with solid-state nanopores to provide localized surface plasmon resonances for signal enhancement. We design and optimize the nano-structure by tuning both the bowtie gap and the bowtie angle, and investigate their influences on field enhancement, thereby achieving single-molecule sensitivity. In addition, we study the field enhancement by introducing an engineered photonic nano-cavity. This further strengthens the electric enhancement. An overall Raman enhancement factor of 2×108 is achieved in our simulation. This is believed to be sufficient for single-molecule sensing. The proposed bowtie-nanopore structure can be multiplexed on a single substrate for simultaneous multi-channel detection, paving the way for demanding applications such as DNA sequencing.

We propose a novel scheme for simultaneous strain and temperature measurement by mode division multiplexing (MDM) in a dual cladding modes fiber up-taper interferometer. The fiber interferometer, with a strong cladding mode and a weak cladding mode, can be constructed by fabricating two optimized adjacent fiber up-tapers along a single-mode fiber. With the MDM method, the temperature and strain measurement resolutions reach ±0.05 °C and $\pm 3.14~\mu \varepsilon $ , respectively, which are much higher than those of the other proposed dual-parameters (temperature and strain) measurement solutions.

We propose a novel fiber micro-displacement sensor based on an embedded fiber dual cladding modes interferometer. This type of interferometer has a very high extinction ratio (ER) of 27.7 dB, with only one very deep resonance dip within C and L bands, enabling it to be used as an intensity-modulated sensor. With it embedded in a cured carbon fiber composites based beam, it shows a high sensitivity response to micro-displacement in ER variation. Experimental results show that there is a quasi-linear relationship between the micro-displacement and its ER variation, with the measurement resolution of 4.67 μm, and the dynamic measurement range of 0∼200 Hz.

The presence of PSS in solution processed high conducting polymer PEDOT:PSS (PH1000) limits the reliability and lifetime of organic photovoltaic devices due to its acidic and hygroscopic nature. We have developed an alternative PSS-free transparent electrode, based on vapor-phase polymerized (VPP) PEDOT in combination with a current collecting silver grid. The hybrid electrode exhibits a low sheet resistance of 1.6 Omega/square with an excellent bending proof performance. The power conversion efficiency (PCE) is 2.63% in a 1.21 cm(2) area device with a stacking structure of PET/Ag-grid/VPP-PEDOT/ZnO/poly[(9,9-bis(3-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)](PFN)/poly(3-hexylthiophene):[6,6]-phenyl-C61 butyric acid methyl ester (P3HT:PC61BM)/MoO3/Al. This efficiency is lower than, but comparable to the PCE (3.36%) of a control device with similar structure PET/Ag-grid/PH1000/ZnO/PFN/P3HT:PC61BM/MoO3/Al. A striking advantage using VPP-PEDOT to replace PH1000 is the high ambient stability of the device. The PCE of un-encapsulated devices after 120 h continuous exposure to ambient oxygen and moisture is retained at a 75% level of its initial value. These results suggest that the Ag grid/VPP-PEDOT is a promising alternative to ITO or high conducting PEDOT:PSS for realization of high efficiency, low cost and stable organic solar cells (OSCs). (C) 2015 Elsevier B.V. All rights reserved.

We demonstrate an arc discharge fabrication method for a high extinction-ratio (ER) single mode fiber (SMF) based dual thin-taper modal interferometer (MI) and investigate the performance of the MI as thermal and refractive index (RI) sensors. With the optimized discharge parameters of a commercial fusion splicer and a simple mechanical taper setup, the MI with about 24 dB ER could be achieved if fabricating two thin-tapers with 20-µm waist diameter on the common SMF. It can be used as a highly sensitive thermal sensor with a thermal sensitivity of −72.8 pm/°C. However, for the high ER MI, the propagation position of the cladding mode is more close to that of core mode in the MI. Hence, its sensitivity to ambient RI variation is not very high, about 10.299 nm/RIU. If using it for dual parameter measurement, its thermal and RI measurement resolutions are ±1.1 °C and ±0.009, respectively, and are 6.6 and 2.4 times bigger than those of the other fiber sensors.

We propose a novel dual cladding modes fiber up-taper interferometer-based surface-mounted acoustic sensor. It consists of two optimized fiber fusion up-tapers along a single-mode fiber that enable it to excite dual cladding modes, which leads to its interference pattern with an extinction ratio of more than 20 dB, guaranteeing it to be used as an intensity-modulated fiber acoustic sensor (FAS) with an ultrahigh sensitivity. Under an acoustic pressure, its simultaneous responses in wavelength shift and intermodal power coupling change contribute to its ultrahigh sensitivity. The sensitivity of the proposed FAS reaches 2.65 V/ $\mu $ Pa and is 33.5 times bigger than that of the piezoelectric acoustic sensor.

A peanut-like hierarchical nano/micro architecture LiNi0.5Co0.2Mn0.3O2 cathode material has been successfully prepared by a simple hydrothermal method combined with a high-temperature calcination process. The characterization results show that the H-NCM has high crystallinity, smaller particle size, uniform particle size distribution, higher specific surface area, lower charge transfer resistance and higher lithium ion diffusion coefficient, which are can facilitate its electrochemical properties. The electrochemical test results reveal that the H-NCM material with peanut-like morphology displayed a higher discharge capacity of 176.5 mA h g−1 and 159.9 mA h g−1 at 0.2C and 10C rates, respectively. And exhibited better cycling stability with capacity retention of 90.0% even at 10C rate after 100 cycles. Meanwhile, the H-NCM cathodes exhibited good practical application performances in commercial with exhibit initial discharge capacity of 2084.2 mA h at 1C rate and capacity retention of 92.17% after 500 cycles.

As a hardware carrier for informatization development, data centers will generate huge heat flux density during operation. Liquid cooling technology is considered as a thermal management method to solve this problem. The development of heat transfer fluids is of paramount importance. In this experiment, TiO2 nanoparticles were successfully modified by supramolecular β-CD, and the corresponding nanofluids were prepared by using the modified nanoparticles. The experimental results show that the nanofluids can be stabilized for more than 50 days, and the average particle diameter of the nanoparticles can be maintained at 38.9 nm after 50 days. At 60 °C, the thermal conductivity of the 0.1 vol% nanofluids is increased by 36.01% compared with the base fluid, and the thermal diffusivity is increased by 58.28%. At a heating rate of 10 °C/min, the average specific heat capacity of the nanofluids is 3.15 times of the air. These results indicate that the heat transfer fluid has tremendous heat transfer potential in data center cooling system applications.

The functionalized TiO2 nanoparticles(β-CD-TiO2-Ag) were manufactured and their characteristics were studied. The thermal storage characteristics of β-CD-TiO2-Ag cooling medium-based nanofluids as an innovative kind of phase change material for eco-friendly cold thermal energy systems were investigated. Dispersion stability is an important research focus for the cooling medium with nanoparticles and this research demonstrated that cooling medium-based nanofluids had good stability. The thermal conductivity of cooling medium-based nanofluids was measured, which was an evident method to improve cold thermal energy storage characteristics. The supercooling behavior of cooling medium-based nanofluids containing β-CD-TiO2-Ag, TiO2 and pure cooling medium was investigated. The experimental results showed that β-CD-TiO2-Ag nanofluids had an observably lower supercooling degree than both of the pure cooling medium and TiO2 nanofluids with the same volume fraction. Moreover, the total freezing time of β-CD-TiO2-Ag nanofluids was less than that of pure cooling medium with volume fraction increased. Supercooling degree could decrease by 63% from 14.6 °C to 5.4 °C with the addition of 0.1 vol% β-CD-TiO2-Ag nanoparticles. These promising results indicated that this research has huge potential in improving the performance of eco-friendly cold thermal energy storage systems and saving resources protecting environment.

We report on a GaN/AlN quantum cascade detector operating in an extended spectral range going from the mid-infrared to visible wavelengths. This broadband detection is achieved thanks to the design of active quantum wells supporting five bound-to-bound intersubband transitions. The photodetector exhibits a broad signal between 4.1 μm and 550 nm. The photocurrent persists up to room temperature. The calibrated responsivity at 77 K under irradiation through a 45° angle polished facet amounts to 7 μA/W at a wavelength of 633 nm and is peaked at 14 μA/W at a wavelength of 720 nm.

High-strength steel (HSS) is gaining increasing use in modern building construction for several reasons, the most notable being that its increased strength can lead to a reduction in self-weight and correspondingly reduced emissions and waste during its manufacture. However, there is little guidance available in design standards when the steel grade exceeds 690 MPa. Such guidance is needed, because the use of thinner plate elements than would normally be encountered in mild steel members leads to an increased importance in local plate buckling participating in the strength limit state, and its interaction with yielding and residual stresses that are germane to HSS members. This paper investigates the buckling strength of welded HSS I-beams numerically, and based on the results of the study it proposes a corresponding strength design criterion that incorporates local buckling and lateral-torsional buckling and their interaction at the ultimate limit state. The finite element model used for the analysis is based on ABAQUS software, and it incorporates the interaction of elastic buckling, yielding, residual stresses induced by welding and geometric imperfections. The numerical formulation is validated against test results reported by several investigators, and it is then used to produce a substantive set of data to investigate the buckling strength of welded HSS beams. It is shown that the buckling strength depends primarily on two parameters: the generalised (or member) slenderness and the section slenderness. It is also demonstrated that coupled modes of failure are possible for slender sections that incorporate the interaction of local and lateral-torsional modes, which traditionally are treated simplistically in current steel design standards by using effective section properties. To overcome the limitations on guidance for the strength design of HSS beams, a set of new strength design equations are proposed from the numerical data, based on the generalised and section slendernesses.

Investigating closely stacked GaN/AlN multiple quantum wells (MQWs) by means of cathodoluminescence spectroscopy directly performed in a scanning transmission electron microscope, we have reached an ultimate spatial resolution of σ CL = 1.8 nm . The pseudomorphically grown MQWs with high interface quality emit in the deep ultraviolet spectral range. Demonstrating the capability of resolving the 10.8 nm separated, ultra-thin quantum wells, a cathodoluminescence profile was taken across individual ones. Applying a diffusion model of excitons generated by a Gaussian-broadened electron probe, the spatial resolution of cathodoluminescence down to the free exciton Bohr radius scale has been determined.

A facile hydrothermal method was adopted to synthesize 3D Mg-Al layered double hydroxide (LDH) microspheres. After being calcined at 500 °C, the obtained Mg-Al layered double oxide (LDO) preserving the morphology of LDH precursor was applied to remove methyl orange (MO) from aqueous solutions. The results show that these LDO microspheres possessing an ultra high adsorption capacity of 3056.8 mg g−1, and the kinetics and isotherms can be fitted well with the pseudo-second-order and Langmuir models. The adsorption process is spontaneous and exothermic, and the mechanism is mainly attributed to the structure reconstruction of LDH with MO incorporated into the interlayer.

A versatile method for synthesis of block copolymer nanoassemblies via initiators for continuous activator regeneration (ICAR) atom transfer radical polymerization (ATRP) dispersion polymerization in a low molecular weight poly(ethylene glycol) (PEG) is discussed. This ICAR ATRP dispersion polymerization uses a low concentration of CuBr2 catalyst, which is stable under atmospheric conditions and is soluble in most polar solvents and employs a polymerization medium of viscous and nonvolatile PEG. Through this ICAR ATRP dispersion polymerization, various block copolymer nanoassemblies, including poly(ethylene glycol)-block-polystyrene, poly(ethylene glycol)-block-poly(methyl methacrylate), and poly(2-hydroxypropyl methacrylate)-block-poly(methyl methacrylate), have been synthesized. The parameters affecting the size and morphology of the block copolymer nanoassemblies are briefly discussed.