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The effect of Ti and Sb elements addition on the microstructures and corrosion resistance of hot-dip galvanized Zn-11Al-3Mg alloy was investigated by scanning electron microscopy (SEM) equipped with energy dispersive spectrometry (EDS), X-ray diffraction (XRD) and Electrochemical workstation, respectively. Results showed that the grain size of the alloy was obviously refined with the addition of Ti and Sb elements, due to Al3Ti phase as the nucleation substrate resulted in the transformation of Al-rich phase from dendrite to petal-like. In addition, the pitting corrosion resistance of the alloy has been significantly enhanced.

Thermoelectric coolers (TECs) are widely used in state-of-the-art thermal management systems. Recently, there is a big trend to power TECs using thermoelectric generators (TEGs). Mainstream research efforts focus on attaining a higher figure of merit ( ZT ) of thermoelectric material, which now faces a great challenge. Alternatively, this article proposes a different approach to improve the performance of TEC, that is, integration of a TEG with a TEC. The TEG converts the collected heat energy into electric current, which reduces the power consumption and enhances the cooling capacity of the TEC. Using different methods of connecting the TEC and TEG, two thermoelectric collaborative cooling systems are proposed. Accurate SPICE models of the two cooling systems are established. The experimental results demonstrate that the discrepancy between the currents flowing through the TEC in the experiments and in the SPICE models is less than 4.8% on average. Based on the verified SPICE models, the proposed TEC-TEG collaborative cooling systems are assessed in terms of power consumption, cooling capacity, coefficient of performance, and cooling efficiency. Compared with a typical Peltier cooling system, the two collaborative cooling systems achieve significant performance improvements.

For evaluating the crack state on solid bridge joint on site, the relationship between gas permeability and crack width of joint concrete is studied both on material and structural levels in this article. In laboratory tests, gas permeability tests on concrete samples with macrocrack are performed, the relationship between the relative gas permeability rate k/k0 and the relative variation of crack width ac is established combining with regression analysis, the fitting curve equation is . when ac increases by 1.125×10-2 mm, the gas permeability increases about 10 times compared with the initial state. In field tests, “pulse tests” are performed on bridge joint based on 3 embedded pulse probes to measure the evolution of gas permeability during bridge operation. The results show, firstly, the gas permeability of joint concrete are in the order of 10-16~10-19 m2, which indicates a good compaction performance; Secondly, an order of magnitude increase of gas permeability of one probe in different ages, or the fact that the gas permeability at one position in solid joint is obviously larger than the other positions, these phenomena indicate the existence of original defects, or the possibility of macrocrack appearance from microcracks, and the crack width increases by about 0.01 mm.

Improving the charge transfer of quantum dots and the electron transport layer can greatly improve the efficiency of quantum dot sensitized solar cells (QDSSC). In this work, we used the ligand exchange method to improve the electron transfer efficiency between CdSe QDs and electron transport layer. The short chain-ligand containing disulfide bond and benzene ring conjugated structure was selected as the surface ligand of CdSe QDs. Because of its unique disulfide bond and conjugated structure, the stability and electron transfer efficiency of QDs in TiO2 layer can be effectively improved. The surface ligand has good stability and the ability to promote charge transfer, which can effectively improve the efficiency of QDSSC. By characterizing of fluorescence performance and the analysis of fluorescence lifetime, the surface of this ligand behaves fluorescence quenching phenomenon and life decay phenomenon after modification. Furthermore, photovoltaic devices constructed by the as-prepared dithiocarbamate functionalization of CdSe@TiO2 have also been assembled with the highest PCE of 5.22%.

With the development of high-power light-emitting diodes (LEDs), the heat flux density of devices has continued to increase, which, in turn, requires the development of increasingly effective methods of heat dissipation to control the working temperature of LEDs. Due to their impressive performance in solid refrigeration and energy harvesting, thermoelectric devices such as thermoelectric coolers (TECs) and thermoelectric generators (TEGs) have been used to develop the methods of heat dissipation, which have been applied to power components and electronic devices. This article proposes a delayed electrothermal collaborative cooling system based on a TEC–TEG system that uses an auxiliary charging technique for energy harvesting. In the designed delay circuit, two power source rails containing a TEG and a charged capacitor are switched automatically to supply energy to a TEC according to the charge on the capacitor and the discharge time of the delay circuit used for energy transmission. The results of experiments show that using the proposed scheme, the electromotive force can be increased by 21.6%, from 0.37 to 0.45 V, in the TEG module compared with the collaborative electrothermal cooling system without auto-delayed power rail switching. The switching time cost of the proposed system was only 0.8 s, and it could continuously supply enough electromotive force to drive the TEC and the overall cooling system. The proposed electrothermal collaborative cooling system with delayed power rail switching and auxiliary charging can improve energy utilization and reduce device cost, which helps to efficiently manage heat dissipation in high-power LEDs.

Magnesium alloys have been widely applied in many fields, because of their high strength-to-weight ratio. However, magnesium alloys have high chemical activity and are easily corroded. The poor corrosion resistance of magnesium alloys greatly limits its further application. In this paper, the zinc phosphate conversion coatings were prepared on the surface of AZ91D magnesium alloys. Nano-zinc oxide was the source of zinc and the zinc phosphate conversion coatings were prepared by the given process: 1.25 g/L NaNO3, 3 g/L C6H8O7 H2O, 2.5 g/L NaF, 5.5 g/L ZnO, 12.5 mL/L H3PO4, reaction temperature 50°C, reaction for 30 minutes. The full immersion uniform corrosion test was conducted for the fabricated coatings. The morphology and composition of corrosion in different corrosion stages were characterized by XRD, SEM and other microscopies. The results showed that: (1) the corrosion process of the conversion coatings could be divided into three stages: the dissolution of the conversion coatings, the corrosion of the matrix and the deposition of insoluble matter; (2) XRD analysis and other methods found that the pine-needle magnesium oxychloride compounds were formed in the process of immersion firstly, and it was dissolved into Mg(OH)2 over time; (3) With the extension of immersion time, Mg(OH)2 increased continuously and played a major role in corrosion prevention. The deposited Mg(OH)2 was divided into two layers. In the initial deposition stage, it was mainly evenly dispersed on the surface of the alloy to form a tightly arranged inner layer. Afterwards, the crystals of Mg(OH)2 agglomerated and formed a sphere, becoming the outer layers.

Nanoelectronics of two-dimensional (2D) materials and related applications are hindered with critical contact issues with the semiconducting monolayers. To solve these issues, a fundamental challenge is selective and controllable fabrication of p-type or ambipolar transistors with a low Schottky barrier. Most p-type transistors are demonstrated with tungsten selenides (WSe2) but a high growth temperature is required. Here, we utilize seeding promoter and low pressure CVD process to enhance sequential WSe2 growth with a reduced growth temperature of 800 °C for reduced compositional fluctuations and high hetero-interface quality. Growth behavior of the sequential WSe2 growth at the edge of patterned graphene is discussed. With optimized growth conditions, high-quality interface of the laterally stitched WSe2-graphene is achieved and characterized with transmission electron microscopy (TEM). Device fabrication and electronic performances of the laterally stitched WSe2-graphene are presented.

Inspired by the structure of puzzles, bombyx mori silk-derived carbon dots (CDs) with abundant negative groups, as jigsaw pieces, were combined with nano-CoP to create a highly effective electrocatalytic interface. The hollow cavity and thin wall of the bamboo-like CDs/CoP nanoarray is beneficial to produce more H˙ radicals and accelerate water decomposition.

In this work, novel porous Co9S8 nanosheet arrays are prepared on Co foam through a simple and scalable chemical liquid-phase processing strategy, which involves the uniform growth of cobalt hydrox...

In this article, a comprehensive and efficient thermal management system is proposed to harvest and reuse the thermal waste of high-power light-emitting diodes (HP-LEDs) for the first time. Besides a conventional cooling system, including a thermoelectric (TE) cooler (TEC), a heatsink, and a fan, the proposed thermal management system also employs a TE generator (TEG), a temperature sensor, a voltage boost converter, and a microcontroller for thermal waste recycling. In this system, some of the thermal waste released by the HP-LED is harvested by the TEG and converted into electrical energy. With the help of a voltage boost converter, the harvested electrical power is used to power a temperature sensor for monitoring the surface temperature of the HP-LED. The entire system is regulated by the microcontroller. The system is elaborately established, tested, and the results are discussed. The experimental results show that the proposed system has an output electrical power of approximately $696.5~\mu \text{W}$ , which is used to power a temperature sensor as a demonstration. The sensor works well, and the discrepancy of the surface temperature of the HP-LED measured by the sensor and by a thermometer is less than 5.38%, which validates the proposed thermal management system.

Bacterial infection is a major threat to human health. However, many antibacterial agents currently used are severely limited due to drug-resistance, and the development of side effects. Herein, we have developed a non-antibiotic nanocomposite consisting of chitosan (ChS) coated silver nanoparticles (AgNPs) and graphene nanoribbon (GNR)-based nanowires for light-triggered eradication of bacteria. The presence of AgNP/ChS significantly enhanced the interactions of the GNR nanowires with Pseudomonas aeruginosa, a clinically common Gram-negative bacterium. Which enables the highly effective photothermal eradication of bacteria by GNR upon near-infrared light irradiation. The nanocomposite was shown to be applicable for the light-triggered eradication of bacterial biofilms and the inhibition of bacterial growth on medical patches used for abdominal-wall hernia surgery.

In the case of assuming that the debonding interface layer was a thin fluid layer and taking the structural boundary conditions into consideration, we derived the expressions of ultrasonic reflection/transmission coefficients in a thick adhesive layer composite structure with debonding and slip defects under water immersion conditions based on the global matrix method. In addition, the finite element method was used to calculate the ultrasonic reflection/transmission coefficients when the bonding interface is debonded and slipped in the bonding structure. The theoretical calculation and simulation results are in complete agreement. The influences of the position of the interface defects (upper or lower interface of the adhesive layer) and defect types (slippage, debonding) on the ultrasonic reflection characteristics were also studied. The results show that if the incident angle and frequency of the sound wave are set appropriately, the perfected bonding, slippage and debonding interfaces can be distinguished.

Freshwater shortage has remained an emerging issue due to increasing potable water demand of global population and ongoing industrial developments. Great efforts have been given to increase the freshwater supply either by exploring new water resources or by recycling of wastewater through various water treatment technologies. Membrane based technology is especially prominent due to the obvious superiorities, including high stability, high permeate flux, high pollutant retention ability, high process intensity, less chemicals utilization, automated process control (easy to process) and operational robustness. Particularly, membrane distillation (MD), which is driven by the vapor pressure gradient, has attracted unprecedented attention because of its eminent advantages, such as energy-saving, high permeate quality, ability to treat feeds with high salinity. Yet, practical applications of classical MD membranes are hindered by the low permeate flux and fouling problem. Thus, it is of great necessity to either overhaul classical MD membranes or fabricate novel MD membranes to promote the practicability. Interestingly, electrospun nanofibrous membranes (ENMs) have attracted tremendous attention in MD. Various features including suitable pore sizes, narrower pore size distributions, high porosities, high surface-to-volume ratios, controllable fiber diameters, and easy functionalities endow ENMs with great potential in MD which has been evidenced by various studies. In this paper, we critically reviewed and commented the research developments on MD application of ENMs. We distinctively emphasized on the design of ENM structures and the relationship between the structure and MD performances. We believe that this review could provide important insight and fundamental understanding with some novel perspective of ENMs in more advanced MD applications.

In this work, the unique glass-ceramics containing thermoelectric AgSbSe 2 crystals were successfully prepared from glass matrices in the (Ge 5 Sb 25 Se 70 ) 1-x Ag x system (x = 0, 2.5, 5, 7.5, 10,15 mol %). Structure and crystallization behaviors of samples were investigated to have a fundamental understanding of the effect of silver doping on the glass matrices. Critical Ag content for precipitation of the pure TE AgSbSe 2 crystals in the present system are at least higher than 5 mol %. Raman spectra explained by the chemical bond approach imply that the continuous depolymerization of glass network with the increased Ag eventually induces the precipitation of AgSbSe 2 crystals from the glass matrix, which, in turn, plays the predominant role in increasing σ RM of glass by around two orders of magnitude.

In this work, series of glass samples in the Ag30As28 (SexTe100-x)42 (x = 15, 30, 50, 70, 85) system are prepared. Effects of the Se/Te ratio on density (ρ), glass transition temperature (Tg), room-temperature conductivity (σ298k) and crystallization behaviors of glasses are investigated, and their associations with the structure of glasses are discussed. Results show that with the increased substitution of Se for Te, the molar volume (Mv) decreases and Tg increases, indicating the increased space packing efficiency and the enhanced structure connectivity. The strengthened structure leads to an abnormal increase of ρ when x is lower than 30 mol%. Further increase of the Se/Te ratio results in the reduction of ρ due to the dominant effect of smaller molar weight (Mw). The σ298k of glasses decreases with Se increasing from 15 to 50 mol%, and then interestingly increases up to the level even higher than that of the sample with the lowest Se content (15 mol%). Raman spectra shows the transformation of main glass structure units from Te-based pyramids to Se-based complexes as the Se/Te ratio increases. According to XRD patterns of samples thermally treated at either lower (215 °C) or higher (265 °C) temperature, with the Se/Te ratio increasing, the dominant precipitated crystals suffer an evolution from AsTe to Ag2Te and finally to the AgAsSe2 semiconductor phase, consistent with the variation trend of Raman spectra. In terms of the structural similarity principle, we thus suppose that the formation of structural units similar to AgAsSe2 semiconductor crystals inversely increases the conductivity of glasses, realizing the mutual benefits of the improved thermal stability and increased conductivity of chalcogenide glasses.

The electrocatalytic conversion of nitrogen gas at ambient conditions represents a novel approach for ammonia synthesis to the sustainable society. It is critical to understand the detailed pathways and mechanisms of this promising process to develop a highly efficient catalyst. Herein, the N, P co-doping carbon (NP-C-MOF-5) catalyst was prepared for electrocatalytic N2 reduction in acid electrolytes under ambient temperatures and pressures. Experimental results showed that there are two products including NH3 and N2H4·H2O on the NP-C-MOF-5 cathode at -0.1 V versus RHE with the yield of 1.08 and 5.77 × 10-4 μg h-1 mgcat.-1, respectively. Moreover, an electrocatalytic pathway on NP-C-MOF-5 was investigated by the electrochemical in situ Fourier transform infrared technique. The results confirmed the formation of N2H y (1 ≤ y ≤ 4) intermediates on NP-C-MOF-5 cathode surfaces, suggesting an associative pathway for the N2 reduction reaction.

Carbon fiber (CF) is a promising material as carbon-based electrode and support for flexible supercapacitors. However, it still suffers from narrow voltage in the aqueous electrolyte due to the water decomposition (1.23 V). Herein, an aerobic pyrolysis is developed to recover aligned carbon fibers from carbon fiber reinforced polymers. More importantly, during this oxygen existence condition, the surface of reclaimed carbon fibers (RCFs) is etched into groove-shaped structure and modified by introducing abundant oxygen-containing functional groups, which significantly expands the negative potential window of RCFs-based electrode to −1.4 V (vs standard calomel electrode) and the working voltage of RCFs-based symmetric supercapacitor to 2.4 V in an aqueous electrolyte of 1.0 M Na2SO4, with capacitance retention of 90% and 93.6% after 10 000 cycles, respectively. This work well matches the aerobic pyrolysis of recovery of CFs from CFRPs and electrochemical performances of RCFs, supplying a new strategy to de...

Desalination provides an effective method to meet the worldwide freshwater crisis. Reverse osmosis (RO) based on polyamide (PA) thin-film composite (TFC) membranes have dominated desalination area with the enhancing desalting properties and decreasing energy consumption. However, it is still an urgent affair for the researchers all over the world to explore more advanced RO desalination materials and procedures to further enhance the popularization of desalination, among which development of superior membranes with as far as possible high water flux and satisfied salt rejections are particularly important. Two-dimensional (2D) nanoporous membranes with sub-nanopores, typically represented by graphene and its derivatives accompanied with some analogues such as molybdenum disulfide (MoS2), have displayed great potential and attracted vast interest in designing such kinds of desalination membranes. Actually, 2D nanoporous membranes might have opened a new era in desalination membranes fabrication and demonstrated brilliant future. Given this, in this review paper we reviewed and discussed the development of 2D nanoporous membranes with sub-nanopores on desalination with emphasis in simulations coupled with experimental studies. Besides, the feasibility and future directions of 2D nanoporous membranes are prospected. We sincerely hope that this paper could provide clues and insights for the future exploration of novel desalination membranes, and further contribute to the advance of desalination membranes synthesis and large-scale production.

Membrane distillation (MD) displays superior characteristics to other technologies to alleviate the ever-increasing freshwater crisis through seawater desalination and/or wastewater recycling. However, the critical challenge in MD is fabricating high-performance membranes. In this study, we fabricated a high-performance hierarchical fibrous composite (HFC) membrane to acquire a high water flux while maintaining a high salt rejection for MD. This HFC membrane comprises of a thin active dense layer with small poly (vinylidene fluoride-co-hexafluoropropylene) (PH) nanofibers to allow maximum mass transfer and a thick support layer with large poly(ethylene terephthalate) (PET) microfibers to give minimum heat transfer. By tailoring the structures of both the active and support layers to reduce the trade-off between the mass transfer and heat transfer during the MD process, the optimized HFC membrane, having a 3 μm thick PH active layer and 70 μm thick PET support layer, achieved the highest reported water flux of 79.21 ± 4.17 L m−2 h−1 and the salt rejection was higher than 99.9% using 3.5 wt% NaCl as the feed under a temperature difference of 40 °C in direct contact membrane distillation (DCMD). Our study describes a novel HFC membrane which demonstrates great achievements in elevating the MD performance.

Single-layer graphene (SLG) sheets can exhibit thermoelectric properties under the control of gate voltage. The controlled factors and regulation mechanism of SLG thermoelectric properties have become research hotspots. In this paper, a SLG thermoelectric parameter model considering carrier concentration and mobility with temperature and gate voltage is proposed. Based on the proposed model, the square resistance ( $R_{\mathrm {s}}$ ) and Seebeck coefficient ( $S$ ) of the SLG are calculated. The results show that the maximum value of $R_{\mathrm {s}}$ decreases from 5.8 $\text{K}\Omega $ to 3.2 $\text{K}\Omega $ at the Dirac voltage when the temperature increases from 100 K to 500 K. A large and stable $S$ can be obtained at high voltages and temperatures. The maximum value of $S$ can reach $161.3~\mu \text{V}$ /K at $T = 500$ K, exhibiting a more obvious thermoelectric characteristic. Simultaneously, the saturation law of the power factor ( $Q$ ) with the change of gate voltage and the amplitude regulation of $Q$ by temperature are obtained. This work can provide a theoretical basis for analyzing the thermoelectric characteristics of SLG.

The novel Tm3+/Sb3+ co-doped phosphate glasses are studied in response to an improvement of blue light emitting source. The analysis of J-O intensity parameters suggests that the present strontium phosphate glass is an appropriate matrix for Tm3+ doping to obtain an enhanced blue emission. The 5 s2-type Sb3+ ion serves as a sensitizer to transfer its strong allowed excitation in the deep UV region to Tm3+ effectively. PL and PLE spectra show that by Sb3+ co-doping, the blue emission of the Tm3+ doped strontium phosphate glass is enhanced greatly, while the excitation band of Tm3+ extends largely to the deep UV region. The emission decay curves of Sb3+ demonstrate the existence of the energy transfer (ET) process from Sb3+ to Tm3+ with the maximum efficiency and probability of ET as 20.43% and 9.20%, respectively. The emission color of these glasses can be adjusted from warm to cold blue via modulating excitation wavelengths. The present work suggests that Sb3+/Tm3+co-doped strontium phosphate glasses are promising for applications in blue emitters and plasma display panels.

The preparation and capacitance performances of Mn (OH)2@ secondary porous Ni nano-architecture foam (Mn (OH)2@SPNiNF) hybrids are systematically studied. The SPNiNF structure is simply obtained via a NiC2O4·2H2O in situ growing process on Ni foam surface, combined with a thermally treated process under Ar gas. Then, a layer of Mn (OH)2 film was electrodeposited onto the above SPNiNF sheet by applying a galvanostatical technique. It is shown that the SPNiNF sheet is composed of interconnected nanoparticles with a diameter range of 100–200 nm. The fabricated Mn (OH)2@SPNiNF electrode exhibited a high specific capacitance of 532.7 F g−1 and an areal capacitance of 906 m F cm−2 at a current density of 0.5 A g−1. The Mn (OH)2@SPNiNF electrode also exhibited a low ions diffusion resistance and a good cycling performance along with 85.7% specific capacitance retained after 5000 cycles. An asymmetric Mn (OH)2@SPNiNF //AC super capacitor exhibited an energy density of 69.1 Wh kg−1 at a power density of 0.6 kW kg−1. These results demonstrated that the Mn (OH)2@SPNiNF was a promising electrode material for supercapacitors.

Due to the excellent physicochemical and biomedical properties, silk fibroin (SF) is a good source for the development of biomedical materials, where size selection of SF during biological application heavily affects the related biomedical behaviors. In this research, silk fibroin was step-wisely filtered and classified by syringe filter into four particle sizes ranges (< 200 nm, 200-450 nm, 450-800 nm and > 800 nm), and was then labeled with iodine-125 (125I-SF) for nuclear imaging. Super early (0-40 minutes) and primary (1-72 hours) biodistribution of 125I-SF were evaluated in Wistar rats. SEM-proved spherical or irregular silk fibroin powder with mixed size was not reuniting with each other in aqueous solution. For early in vivo distribution, four SF mostly gathered in the gastrointestinal tract (120-140 times to the background (accumulation in upper limb of left hind leg)), and a small amount (20-40 times) in bladder after injection within 40 min. For SF (< 200 nm, 200-450 nm and 450-800 nm) during the first 72 h, although there was decreasing trend over time, the gastrointestinal accumulation still accounted for the majority. Meanwhile, most of the SF in the bladder was expelled within 1 h and SF could be rarely seen in liver. Notably, SF (> 800 nm) almost gathered in the liver instead of the gastrointestinal tract after 10 h and got the peak value (280 times to the background) at around 48 h. The particle size directly determined the passive distribution of SF in vivo, which can not be ignored during drug design. Above all, these preliminary results may be referable for further biomedical application on silk fibroin.

Intercellular glycoligand-receptor interactions are implicated in a number of disease-related processes. Effective tools that target these receptors may facilitate disease theranostics. However, owing to their low binding affinity, multivalent presentation of glycoligands is needed to increase the avidity with transmembrane receptors. While previous strategies focus on the covalent coupling of glycoligands to a synthetic backbone, we show here that the use of graphene oxide (GO) greatly enhances the cellular and tissue imaging ability of a small-molecule fluorescence glycoprobe. We determine that GO with an optimum size may serve as a clustering platform to reinforce the interaction of the glycoprobe with its selective receptor on a cancer cell. This phenomenon has been consistently observed with the xenograft tissue of a tumor-bearing mouse. Using this principle we have further constructed a supramolecular glycocomposite by co-assembling the glycoprobe and an anticancer drug onto a single GO surface. In addition to imaging ability, this material displays improved toxicity for liver cancer cells that over express the glycoprotein receptor, when compared to the control cells.

Supramolecular assembly between conjugated polymers and fluorescent dyes produces a unique class of fluorogenic “nanogrenades”. These nanomaterials have shown the ability to image as well as irreversibly destruct amyloid β fibril plaques by simple light irradiation.

When light passes through the interface of two materials with different Seebeck coefficients (S), a temperature gradient will be occurred at the interface, causing photo-thermoelectric effect, which in turn produces photocurrent. Since photocurrent is positively correlated with the difference of Seebeck coefficient of the material and negatively correlated with the resistance of the material, a method for calculating the thermoelectric parameters of graphene with double-gate structure is proposed in this paper. Taking the back gate voltage as a global variable and the top gate voltage as a local variable, the resistance of graphene sheets in different regions is regulated. By solving the resistance of graphene sheets in two regions with top gate and without top gate, their Seebeck coefficients can be obtained. The results show that under the control of the global back gate voltage, a small range of fine adjustment of the top gate voltage can accurately achieve precise control of the resistance and Seebeck coefficient of different regions of the graphene sheet. This paper provides a theoretical basis for the subsequent study on the photoelectric characteristics of graphene.

A corn-like CeO2/C coaxial cable textured by a cerium oxide shell and a carbon core was designed to sense NO. The carbon core possesses high electrical conductivity, and the CeO2 surface delivers excellent electrocatalytic activity. The sensor, typically operated at 0.8 V (vs. Ag/AgCl), exhibits a detection limit of 1.7 nM, which is 4-times lower than that of CeO2 nanotubes based one (at S/N = 3). It also displays wide linear response (up to 83 μM), a sensitivity of 0.81 μA μM−1 cm−2, and fast response (2 s). These values are highly competitive to that of a CeO2 tube (0.92 μA μM−1 cm−2 and 2 s). The sensor was used to quantify NO that is released by Aspergillus flavus.

In this article, transparent oxyfluoride glass ceramics containing β -NaYF4 nanocrystals were successfully prepared via Gd3+ doping. Compared to conventional non-doped glasses, the thermal treatment temperature required for the precipitation of β -NaYF4 nanocrystals can be lowered with the doping of Gd3+. Furthermore, under the same thermal treatment condition, more β -NaYF4 nanocrystals were precipitated in Gd3+ doped ones, which greatly improves the luminescence efficiency of rare earth doped glass ceramics. Possible mechanism for the Gd3+ doping induced enhanced upconversion luminescence phenomenon was proposed, based on thorough structural and optical characterizations. The results revealed that the doping of Gd3+ ions could decrease the crystallization activation energy and promote the formation of Y-F-Na bonding, which helps the precipitation of β -NaYF4 nanocrystals. Consequently, a large enhancement in upconversion luminescence was achieved. Moreover, the strategy can be successfully applied to the development of other glass ceramic systems for various optoelectronic applications.

Herein, high flux nanofiltration (NF) membranes were fabricated by combined procedures of electrospinning, layer-by-layer (LBL) assembly, and phase inversion. The membranes displayed three-dual structure constituted polyether sulfone (PES) coating layer, LBL assembly modified electrospun polyester (PET) nanofibrous mats, and non-woven supports. High flux NF membranes thus prepared are characterized by ultrathin phase inversion layer (∼10 μm) while that of conventional membranes are 100–150 μm, implying that very high flux could be expected. Various factors including electrospinning conditions, chitosan (CHI)/alginate (ALG) concentration, PES concentration, exposed time, coagulating temperature, thermal treatment, and sulfonated poly ether ketone (SPEEK) content were systematically investigated. Structures of the membranes were characterized by field emission scanning electron microscopy (FESEM), mechanical properties test, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and static contact angle measurements. The separation experiments indicated that thus prepared membranes exhibited high flux of as high as ∼75 L m−2 h−1 with Mg SO4 rejection of ∼80%.

In the present work, Tm3+-doped strontium phosphate glasses modified by Sn2+ are investigated. Sn2+ and Tm3+ can be co-excited with the deep UV light to emit the tunable blue light. The reinforced and purified blue emission is obtained at the excitation bands toward the deep-UV part of the spectrum. Photoluminescence emission and excitation spectra, and emission decay curves indicate consistently that the improved Tm3+ emission is in association with the presence of Sn2+ in the host glass where energy transfer from Sn2+ to Tm3+ occurs. Relevant mechanism is discussed.

Er 3+ singly doped and Er 3+ /Yb 3+ co-doped bulk La 2 O 2 CN 2 phosphors were prepared by a classical solid-state reaction of Li 2 CO 3 , Er 2 O 3 , Yb 2 O 3 and LaF 3 under NH 3 gas flow in the presence of graphite at low firing temperature. The crystal structures of La 2 O 2 CN 2 : Er 3+ and La 2 O 2 CN 2 : Er 3+ /Yb 3+ were confirmed by X-ray diffraction (XRD), and all the samples crystallize in a tetragonal structure with space group I4/mmm. FE-SEM was applied to investigate the particle sizes and morphologies. Upconversion luminescence characteristics have been studied in detail by varying Er 3+ and Yb 3+ contents. Under 980 nm light excitation, Er 3+ doped La 2 O 2 CN 2 samples exhibited weak blue and strong green emission peaks which are corresponding to the 4 F 7/2→ 4 I 15/2 and 2 H 11/2 → 4 I 15/2 transitions of Er 3+ . While, Er 3+ /Yb 3+ doped La 2 O 2 CN 2 samples exhibited blue, green and red emission peaks which are respectively corresponding to the 4 F 7/2→ 4 I 15/2 , 2 H 11/2 → 4 I 15/2 , 4 S 3/2 → 4 I 15/2 and 4 F 9/2 → 4 I 15/2 transitions of Er 3+ and also the emission intensity are enhanced due to the energy transfer from Yb 3+ to Er 3+ .

In this work, glass samples of compositions of As 40-0.4x (Se 15 Te 85 ) 60-0.6x Ag x (x = 0, 10, 16.7, 20, 25 at%) are prepared. The structural transformations of glasses are deduced from the variations of glass densities and Raman spectra with the addition of Ag. Differential scanning calorimetry is applied to determine the characteristic temperatures, evaluate the thermal stabilities against crystallization, and investigate the crystallization kinetics under non-isothermal conditions. Thermal treatment of the as-prepared glass samples is carried out at both low (190 °C) and high (260 °C) crystallization temperatures. X-ray diffraction patterns demonstrate that crystals precipitated from glass matrices are pure As-Te(Se) phases free of Ag. The results are consistent with the Raman spectra. The relevant mechanism can be understood based on the dual chemical role of the Ag addition on the variations of glass network.

Highly oriented Co-MOF nanoneedle arrays arein situconstructed on Co foam (Co-MOF@Co) by using a one-pot solvothermal strategy. As-prepared Co-MOF@Co can be directly served as a binder-free electrode for supercapacitor, which exhibits wonderful electrochemical performances, i.e. high specific capacitance (12783.0 mF cm-2or 1164.2 F g-1), exceptional cycling stability (90.5% retention over 10 000 cycles at 250 mA cm-2) with a loading of 10.98 mg cm-2. Meanwhile, an asymmetric supercapacitor of AC//Co-MOF@Co delivers a high ratability (87% retention upon ten-fold current density) and high energy density of 43.4 W h kg-1at the power density of 145.1 W kg-1.

The commonly used commercial hydrophobic membranes are facing great challenges in wetting and low permeation when used in membrane distillation (MD) because of the limited materials and structures. To address these problems, we herein fabricated a kind of carbon nanotubes (CNTs) enhanced membrane with high flux and stable performance in membrane distillation, where a porous hydrophobic network of multi-walled carbon nanotubes (MWCNTs) was spray-coated onto the commercial flat-sheet hydrophobic membrane surface. Then, we systematically investigated the impact of the CNTs loading on the substrate surface properties, membrane structures and MD performance (flux and rejection), and experimentally illustrated the role of CNTs towards improving MD performance. Results illustrate that there is an optimal match of the CNTs spray amount with the substrate pore size and the substrate materials to achieve the maximum specific surface area of membrane, and thus the maximum flux and salt rejection of the resultant CNTs-enhanced membrane, which is governed by the interfacial energy of the CNTs and the substrate, and thus the CNTs packing density. Results find that the CNTs packing density decreases with the decrease of the substrate free surface energy, and the loosest CNTs packing is formed on the polytetrafluoroethylene (PTFE) membrane with the lowest free surface energy. Under the optimized conditions, the CNTs enhanced PTFE membrane exhibited salt rejection of >99.9% and water flux of 33.2 LMH in MD, which was three times as high as that of the pristine PTFE membrane under the temperature difference of 40 °C between hot and cold streams when operated in direct contact membrane distillation. Our research here provides an efficient method to enhance the permeation and stability of commercial membranes by spray-coating CNTs and also supplies some insights on the design of next-generation MD membranes.

Polyamide thin film composite (PA-TFC) membranes are finding more and more popularity in desalination via both reverse osmosis (RO) and forward osmosis (FO) process, which can effectively alleviate worldwide freshwater crisis through translating seawater into potable water. Despite of huge progresses, great challenges still exist in trade-off between water flux and salt rejections, surface fouling, chlorination, and concentration polarization. This has encouraged tremendous research in tailoring structures and properties of virgin PA-TFC membranes. Nevertheless, it seems that major research has focused on the surface polyamide layer. It should be noticed that sublayer also significantly affect the PA-TFC membranes. Fortunately, researchers have realized this fact in recent years and have done some important and meaningful work. From this point of view, this paper reviews and discusses the state-of-the-art developments on achievements of sublayers adjustment for tailoring PA-TFC membranes used in RO and FO desalination. Traditional sublayers adjustment and novel electrospun nanofibrous membranes (ENMs) sublayers are highlighted. It also provides an insight for future research directions combined with comments and perspectives. It is sincerely expected that this review paper can provide some clues for further in-depth evaluation and research in exploring more advanced PA-TFC membranes by adjusting sublayers.

The crystallization behaviors of As-Se-Bi chalcogenide glasses were investigated by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Three models were used to study the glass transition behavior and the activation energy. Results showed thermal stability of glass against crystallization decreased with Bi addition in As-Se-Bi system. The mechanism of crystal growth in glasses was also studied by the Avrami exponent n. For B0, B2.5 and B5, n values are 3.12, 1.59, and 2.21 (low temperature) and 4.61 (high temperature), respectively. The thermal stability of glass is in good agreement with glass network structure. It was found that glass network structures closely associated with the Bi content and As/Se ratio were studied by X-ray diffraction and Raman spectroscopy. And the different ratios lead to the change of Bi2Se3 crystalline orientation. This article is protected by copyright. All rights reserved.

The seasonal outbreak of influenza causes significant morbidity and mortality worldwide because a number of influenza virus (IV) strains have been shown to infect and circulate in humans. Development of effective means to timely monitor as well as block IVs is still a challenging task. Whereas conventional fluorescence probes rely on a fluorimetric change upon recognizing IVs, here we developed simple "Supra-dots" that are formed through the aqueous supramolecular assembly between a blue-emitting polymer dot and red-emitting sialylglycan probes for the ratiometric detection of IVs. Tuning the Förster resonance energy transfer from polymer dots to glycan probes by selective sialylglycan-virus recognition enables the fluorescence ratiometric determination of IVs, whereas the presence of unselective, control viruses quenched the fluorescence of the Supra-dots. Meanwhile, we show that the Supra-dots can effectively inhibit the invasion of a human-infecting IV toward a human cell line, thereby making possible a unique bifunctional, supramolecular probe for influenza theranostics.

In this work Er3+ doped chalcogenide glasses structurally modified by indium (In-ChG) was prepared. The mid-infrared spectroscopic properties and solubility of Er3+ in In-ChG was investigated and compared with those of gallium modified glasses (Ga-ChG). Thermal stability, mid-infrared (MIR) photoluminescence (PL), absorption spectra of both Ga-ChG and In-ChG were characterized and compared in parallel. Both the obtained MIR absorption and emission cross sections of In-ChG are higher than those of Ga-ChG. The theoretical branching ratio and decay lifetimes of 4I11/2-4I13/2 transition calculated from Judd-Ofelt theory were compared with those obtained from experiments. The tested and calculated lifetime is similar and it indicates high radiative quantum efficiency. Raman spectra reveal the fact that In-ChG possess lower phonon energy than that of Ga-ChG, which might possibly give rise to the improved MIR emission. Er3+ doped In-ChG chalcogenide glass is a potential material for MIR fiber laser application.

The short range order structure of Bi13Ge20Se67-xTex glasses (x = 0, 5, 10, 15, 20 at.%) is explored by using high-resolution X-ray photoelectron spectroscopy. Results show that the incorporated oxygen from surface containment of specimens and Te substitution for Se exert important impacts on the network structure of glasses. Oxygen breaks the Ge Ge homopolar bonds in the Ge Se Bi glass, leading to a significant reduction of the over-constrained Ge Ge (Se)3 ethane-like units. Te addtion promotes the formation of mixed BiSe(Te)3/2 nanolayers as crystal precursors, thus initiating crystallinzation in competition to a topological self-organization process. The present work will be helpful to deepen the understanding of ChG glasses for applications in fields of optoelectronics and photonics.

The thermal oxidation behaviour of Ti-6Al–4V alloy as well as pure titanium under external bending strains was investigated through experimental and modelling approaches. Dislocation accumulation due to creep deformation was responsible for the acceleration of oxidation at initial stage. However, the promoted formation of alumina would retard the subsequent scale growth. Moreover, the bending strain had a multi-fold influence on the formation of oxygen diffusion zone. An analytical model was developed to predict the variation of growth stress within the oxide layer along with time. The prediction results agreed well with experimental data.

In the present work, samples in composition of (100-x)/2As 2 S 3 -(100-x)/2Ag 2 S-xAgCl (x = 40, 45, 50, 55mol%) were prepared. X-ray diffraction and differential scanning calorimetry under non-isothermal conditions were recorded from which crystalline phases, characteristic thermal temperature, criteria for thermal stability against crystallization and crystallization kinetic parameters are obtained for evaluation of their glass formation and crystallization behaviors. Raman spectroscopy was used in following the structural changes with variation of AgCl content. Thermal treatments were made on amorphous samples under different conditions, and the nonlinear dependence of crystallization behaviors on AgCl content is discussed. Results of the present work obtain the optimal silver chloride based chalcogenide glass composition as the stable membrane material for application in ion-selective electrodes for dual Ag + /Cl − ions determination.

The Ce/Cr coating was homogenously deposited onto the reticulated open-cell Ni–Cr–Fe alloy foam by the pack cementation process. The mechanical properties of the Ce/Cr coated alloy foams were investigated by the quasi-static compression test. Simultaneously, the deformation and failure mechanisms of Ce/Cr coated alloy foams were discussed. The results show that the adding amount of CeO2 powders influences the mechanical properties of the Ce/Cr coated alloy foams. Despite an increase in density as compared to the uncoated foams, the Ce/Cr coated foams exhibit improvement in both yield strength and energy-absorption performance. Especially, the energy-absorption performance of 2% Ce/Cr (mass fraction) coated alloy foam is averagely 1.9 times as high as that of the bare Ni–Cr–Fe alloy foam. In addition, the mechanical properties of the Ce/Cr coated alloy foams increase with the increase of strain rate. The distortion and cracking are mainly the deformation behavior of the Ce/Cr coated alloy foam, confirmed by SEM images.

Tb 3+ doped SiO 2 -ZnO-BaO glasses are prepared by melting quenching method and their unique photoluminescent properties for the UV excitation are studied by using emission/excitation spectra and decay curves. Glasses in the composition (mol%) of 60SiO 2 -xZnO-(40-x)BaO-0.2Tb 3+ (x=30, 20, 10) show the strongest emission peaking at 436 nm which is different from majority of other reported work. Lower content of the free OH groups mainly contribute to this phenomenon due to the decreased probability of the multi-phonon aided non-radiative relaxation process from 5 D 3 to 5 D 4 energy levels of Tb 3+ ions. The Tb 3+ concentration also affects the 5 D 3 / 5 D 4 emissions as a result of the cross-relaxation effect on two nearby Tb 3+ ions ( 5 D 3 - 5 D 4 ⇒ 7 F 6 - 7 F 0 ). Moreover, by adjusting Tb 3+ concentration and/or ZnO/BaO concentration ratio of the host glass we obtained the adjustable emission with the required CIE chromaticity from blue to green, suggesting that the present Tb 3+ -doped SiO 2 -ZnO-BaO glasses are potential as blue/green dual-color luminescent materials for different applications.

Thermal boron diffusion, which forms highly doped and shallow p-emitters on phosphor-doped silicon wafers, is one of the primary processes in commercial-scale production of n-type cells. Here, we report on the use of nontoxic and nonvolatile borosiloxane sols as the spin-on boron source. In comparison to the tribromide (BBr3) boron diffusion that is applied in the production of most commercial n-type cells, borosiloxane boron diffusion may have potential advantages in terms of cost, safety, operability, etc. The borosiloxane sols studied here were formed from a cross-linking reaction between boron acid and a mixture of two types of silicon alkoxides, methyltriethoxysilane (MTEOS) and dimethyldiethoxysilane (DMDEOS). The MTEOS/DMDEOS ratio was found to be the key factor determining the synthetic period, net structure, thermal transformation property, and coating behavior of the borosiloxane sols. In combination with the spin-coating method, the performance of borosiloxane boron diffusion into phosphor-doped silicon wafers (1–3 Ω·cm) was systematically investigated by varying the borosiloxane composition (boron/silicon or MTEOS/DMDEOS ratio) and the diffusion process parameters (temperature, ambience, and period of individual sub-steps), and by relating them to the resulting sheet resistance and boron doping profile. The results show that under the diffusion conditions in conventional cell production lines, the formed p-emitters can have variable sheet resistance in the range of 35–582 Ω/□ and boron doping depth of 100–300 nm.

To exploit high-quality separators for lithium ion batteries, current research activities are mainly focused on the modification of microporous polyolefin membranes by coating them with inorganic particles to achieve comprehensive improvements in their thermal stability, electrochemical compatibility, and overcharge protection. Here, we report a separator made by coating boehmite (AlOOH) particles on microporous polyethylene (PE) membranes. Compared to the commercially applied coating materials, e.g., aluminum oxide (Al2O3), AlOOH allows for a substantial reduction in the coating thickness, while ensuring excellent thermal stability of the modified PE membrane. Our study shows that this is due to the formation of an interlocking interface structure that interconnects the PE membrane and AlOOH coating layer as soon as PE melts at about 140 °C, preventing the modified PE membrane from shrinking at subsequently elevated temperatures. The modified PE membrane exhibits suitable electrolyte wettability to facilitate ion transport through it. Thus, the lithium ion batteries employing it as a separator could attain substantially improved electrochemical performance. Furthermore, the AlOOH-coated PE separator was also found to provide an excellent overcharge protection.

Samples with compositions of Ge 20 Se 67−x Te x Bi 13 (x=0, 5, 10, 15 and 20 mol%) were prepared and characterized by XRD, Raman spectroscopy and DSC. XRD patterns and Raman spectra present consistent evidences of glass transition and crystallization in association with the variation of the structure network due to the substitution of Te for Se. Precipitation of thermoelectric (TE) crystals experiences an evolution from Bi 2 Se 2 Te (BST) to Bi 2 SeTe 2 (BTS) phases with the increasing Te content. Based on DSC data performed at five heating rates, crystallization kinetics is analyzed by using Kissinger's relation, Ozawa model and Augis-Bennett approximation. Different methods show the identical evaluations of characteristic activation energies ( E c ), while additional parameters of frequency factor ( K 0 ) and Avrami exponent ( n ) are available with AB method. In particular, calculated E c and K 0 demonstrate that with the substitution of Se by Te the crystallization process of the target TE BST crystal phase is much enhanced while that of the undesired GeSe 2 phase is slightly hindered.