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This paper investigates the method to improve the property that can decrease the impact response of composite plate. Embedding the super-elastic shape memory alloy wires into composite plates has increased the attention of material researchers. Super-elastic shape memory alloy has the properties of absorbing mechanical energy, large recoverable deformation and so on. In this study, experiments were conducted to analyze the impact properties of composite plates with Ni-Ti SMA wires. Composite plates with Ni-Ti SMA wires and without Ni-Ti SMA wires were subjected to two impacts respectively. This study measured the responses of two impacts. The results showed that the composite plate with Ni-Ti SMA wires were subjected to a second impact with a peak deflection of 5.47 mm, which was only 0.22 mm larger than the first impact. The relevant data of the composite plate without Ni-Ti SMA wires were 9.02 mm, 1.22 mm, and serious damage occurred. It was verified that the Ni-Ti SMA wires improved the impact resistance of the composite plate. After studying the impact tests of variable diameters of SMA wires embedded at the low layer of composite plate, it was shown that as the diameter of SMA wires increased, the impact resistance of composite plates was improved.

CrFeCoNi and CrMnFeCoNi coatings were prepared using laser remelting technology. The microstructure and phase composition of coatings were investigated. X-ray diffraction (XRD) results indicated that CrFeCoNi and CrMnFeCoNi coatings presented face-centered cubic structure. Electrochemical measurements were used to reveal the corrosion behavior of coatings. Results showed that CrFeCoNi coating exhibited lower corrosion current density, lower passive current density and higher charge transfer resistance than CrMnFeCoNi coating in H2SO4 solution (0.5 mol/L). This indicated that CrFeCoNi coating possessed higher corrosion resistance. Mott-Schottky analysis revealed that the passive film formed in CrFeCoNi coating possessed lower donor density value in contrast with that of CrMnFeCoNi coating, suggesting that CrFeCoNi coating formed a more protective passive film. The corrosion mechanisms of coatings were also revealed.

The occurrence of membrane fouling has resulted in limited wastewater treatment applications. The development of superhydrophilic-underwater superoleophobic materials has received significant attention owing to their good anti-fouling properties. However, to fabricate such materials need costly regents and tedious steps. Thus, developing a one-step process to prepare a low-cost material for oil/water separation is still desired. In this study, bio-inspired from an arachnid, inorganic carbon nanotube stainless steel meshes (CNT@SSMs) having superhydrophilic-underwater superoleophobic and excellent anti-fouling properties and a unique fiber structure were fabricated via a one-step thermal chemical vapor deposition method. The CNT@SSMs had a small pore size enabling a high water flux of 10,639 L m−2h−1 and the separation of oily wastewater, including various emulsions, at a high rejection ratio of >98.89%. As a result of its excellent chemical stability under high temperatures, a broad pH range, and saline environments, the CNT@SSM has the potential to be used in extreme conditions. In summary, these CNT@SSMs are easy to fabricate and are low-cost as a result of inexpensive reagents involved. Moreover, these novel superwetting membranes are promising candidates for treatment of hazardous oily wastewater.

The ability to control the potential landscape in a medium of interacting particles could lead to intriguing collective behavior and innovative functionalities. Here, we utilize spatially reconfigurable magnetic potentials of a pinwheel artificial spin ice structure to tailor the motion of superconducting vortices. The reconstituted chain structures of the magnetic charges in the artificial pinwheel spin ice and the strong interaction between magnetic charges and superconducting vortices allow significant modification of the transport properties of the underlying superconducting thin film, resulting in a reprogrammable resistance state that enables a reversible and switchable vortex Hall effect. Our results highlight an effective and simple method of using artificial spin ice as an in-situ reconfigurable nanoscale energy landscape to design reprogrammable superconducting electronics, which could also be applied to the in-situ control of properties and functionalities in other magnetic particle systems, such as magnetic skyrmions., Comment: To appear in Nano Letters

Chiral transcription and enantioselective separation have garnered significant research interests and showed potential for a broad range of practical applications. Here, we present a novel and facile strategy for chiral templating and enantiomers resolution by coating metal-ion-mediated l -phenylalanine derivatives (LPF/M) with graphene oxide (GO) via simply mixing. The LPF/M hydrogels precipitate from the liquid by encapsulation of GO through coordination interactions and hydrogen bonds, making heterogeneous transfer and separation possible. The chirality inversion of the internal LPF/M nanostructure could be triggered by different addition of metal ions, which further provides means for controlled chiral transfer of guest molecules on the outer GO surfaces as demonstrated in the transcription of thioflavin T (ThT) and 3-aminopyridine (AP) at the supramolecular level. Changing the metal ions also provides control over enantiomer selectivity with outstanding efficiency and reproducibility, as revealed by the separation of racemic mixtures of phenylanine (>98%), lysine (>96%), and histidine (>97%). In addition, the resultant hybrid materials exhibit excellent environmental stability and reusability (more than 20 times) with significant separation efficiency. More importantly, the GO-coated LPF/M could determine the enantiomeric composition of various chiral substrates. The proposed strategy opens up a promising avenue for practical chiral separation application.

Clay often has severe detrimental impacts on cement-based materials. Therefore, it is necessary to investigate the mechanism causing the deterioration to improve the service life of cement-based materials. Based on accurate dimensional analysis, a mechanism that influences clay is proposed: the intercalation of the side chains of superplasticizer molecules in the interlayer space of the clay. To lessen this harmful effect, a new clay-resistant admixture (CRA) possessing cationic groups of small molecular size was synthesized through a novel dimensional design. The length and width of the side chains of this superplasticizer molecule were 9.50–17.50 and 0.25–0.40 nm, respectively, with a radius of ~3.74 nm in solvent, which is larger than the interlayer spacing of montmorillonite (i.e. 1.09–2.14 nm). The longitudinal and latitudinal lengths of the CRA molecule were 0.468 and 9.456 nm, respectively, ensuring intercalation in the interlayer of montmorillonite. The increase in interlayer spacing of the clay was 0.364 nm following addition of polycarboxylate superplasticizer (PCE) plus CRA and 0.632 nm following addition of PCE, which suggests that the CRA plays the role of a ‘sacrificial agent’ that is preferentially intercalated into the interlayer space of clay to further prevent the side chains of the superplasticizer molecules from entering the interlayer. The aim of this study was to propose a suitable means of synthesizing a new CRA to address the impact of clay through dimensional design and mechanism analysis, which contributes to the theoretical study and technological improvement of cement-based materials.

Chiral nanomaterials with circularly polarized luminescence (CPL) have attracted increasing attention as they show improved luminous efficiency and high contrast images in optical displays. Herein, nanotwisted fibers with bright full-color CPL are developed through the co-assembly of chiral phenylalanine derived gelators and achiral aromatic molecules. The synergic effect of π-π stacking and hydrogen bonding interactions between the chiral and achiral building blocks results in long-range ordered self-assembly, enabling the chirality of the gelators to be better transmitted to the achiral aromatic molecules. Highly ordered co-assemblies lead to the formation of supramolecular gels with high glum values which range up to 10-3. Moreover, nanoassemblies with white CPL are obtained by tuning the ratio of colorful achiral aromatic molecules in the gels. These nanotwisted gels show diverse colors or even white circularly polarized light when coated on UV chips, which enable their future application in the construction of low-cost and flexible light-emitting devices such as circularly polarized organic light-emitting diodes (CPOLEDs).

Herein, we report a bifunctional electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) by pyrolysis of zeolitic imidazolate framework-67 (ZIF-67), melamine, and PVP composites solid gel. During the pyrolysis, ZIF-67 formed N and Co co-doped carbon nanotubes on the surface (Co@CNT/NC), melamine and PVP have been converted into N-doped carbon (NC) substrate. Our Co@CNT/NC composites display the overpotential of HER and OER at current density of 10 mA cm−2 only need 136 mV and 280 mV, respectively. The synergistic effect of catalytic active sites such as metallic Co, Co–N bond, and N-doped carbon, and the large specific surface area caused by special morphology of the materials, enabled the catalysts to exhibit superior catalytic performance of HER and OER. The work provides a new idea to construct highly efficient HER and OER dual-functional electrocatalysts.

To broaden the application of oxime ester and obtain a photoinitiating system with high performance in visible light photopolymerization, we prepared the two arylaminocarbazole oxime ester (CZ–OXE), OXE1 and OXE2, with visible absorption. The multicomponent initiation systems of OXE as one of the components were evaluated in visible photopolymerization. Synergism between OXEs and diaryliodonium salt (ION), N-vinylcarbazole (NVK), ethyl 4-dimethylamino benzoate (EDB), and triphenylphosphine (TPP) were experimentally studied via steady state photolysis and fluorescence quenching. The thermodynamic feasibility for electron transfer reaction in photoinitiating systems was confirmed by cyclic voltammetry experiments. Electron spin resonance techniques proved the production of active species in the systems. Polymerization experiments under a 405 nm light source showed that the two-component initiation system OXEs/ION was more efficient than the one-component initiator OXEs. Similarly, three-component OXEs/ION/co-initiator photoinitiating systems are more efficient than OXEs/ION systems.

Although numerous fluorescent probes are designed to detect the pH value in the past decades, developing fluorescent probes for extreme alkalinity (pH > 14) detection in aqueous solution is still a great challenge. In this work, we utilized 1H-imidazo[4,5-f][1, 10] phenanthroline (IP) group as the recognition group of hydroxyl ion and introduced two triethylene glycol monomethyl ether groups to improve its solubility. This IP derivative, BMIP, possessed good solubility (25 mg/mL) in water. It displayed high selectivity toward extreme alkalinity (pH > 14) over other ions and pH (from extreme acidity to pH = 14). From 3 to 6 mol/L OHˉ, the exact concentration of OHˉ could be revealed by BMIP and the whole detection process just needed a short time (≤ 10 s). Meanwhile, it exhibited good anti-interference ability and repeatability during the detection process. Through optical spectra and NMR analysis, its detection mechanism was proved to be deprotonation by hydroxyl ion and then aggregation-induced enhanced emission. Our study presents a new basic group based on which researchers can develop new fluorescent probes that can detect extreme alkalinity (pH > 14) in aqueous solution.

Due to the great similarity to the natural extracellular matrix and minimally invasive surgeries, injectable hydrogels are appealing biomaterials in cartilage and bone tissue engineering. Nevertheless, undesirable mechanical properties and bioactivity greatly hamper their availability in clinic applications. Here, we developed an injectable nanocomposite hydrogel by in situ growth of CaP nanoparticles (ICPNs) during the free-radical polymerization of dimethylaminoethyl methacrylate (DMAEMA) and 2-hydroxyethyl methacrylate (HEMA) matrix (PDH) for bone regeneration. The ICPNs are self-assembled by incorporation of poly-l-glutamic acid (PGA) with abundant carboxyl functional groups during the formation of carboxyl–Ca2+ coordination and further CaP precipitation. Furthermore, the carboxyl groups of PGA could interact with the tertiary amines of DMAEMA fragments and thus improve the mechanical strength of hydrogels. Upon mixing solutions of DMAEMA and HEMA bearing PGA, Ca2+, and PO43–, this effective and dynam...

Rocking Brownian motors achieve directional motion in highly diffusive environments by combining an inherently asymmetric static potential energy landscape and an oscillating “rocking” force [1, 2]. Our nanofluidic imple- mentation [3] features a confining wall with a ratchet-type nano-topography and AC electric fields as driving force. The potential energy landscape is due to electrostatic interactions between the charged particles and wall surfaces in close proximity. Based on this scheme, we have developed a nanoparticle size-separation device [4]. Along the particle transport direction, one of the confining walls features a sawtooth-like topography with a superimposed slope. In turn, we obtain a ratchet-shaped potential with increasing potential energy barrier heights caused by the decreasing nanofluidic gap. A sharp drop in particle current occurs as the potential barriers increase. The drop happens the later, the smaller the particle size. This allows for a sequential separation of the particle suspension into multiple sub-populations. The device was modeled by solving the Fokker-Planck equation. We show that the physics of the separation mechanism is governed by the energy landscape under forward tilt of the ratchet. The separation resolution is thus only dependent on the applied force. Experimentally, we demonstrate the separation of spherical gold particles of nominal 80 and 100 nm diameters with an applied voltage of 3.5 V and a sorting time of 20 s. We achieve a resolution of 2 nm, in accordance with our simulation results.

High-power and high-quality pulsed fiber lasers with low repetition frequency are widely applied to various fields ranging from basic science to industrial applications. Coherent beam combining (CBC) is a significant method to obtain that beam, but few methods used for large-scale CBC of pulsed fiber lasers with low repetition frequency were presented. To realize it, a new method based on a continuous carrier was designed, where the continuous wave worked as the beacon signal, and the stochastic parallel gradient descent algorithm was employed for phase locking and tilt correction. The beam combining experiment revealed that the combining efficiency of two lasers with a repetition frequency of 15 kHz and a pulse width of 100 ns was 95%, and the fringe contrast in the center of the far-field spot was improved about three times. This method promises to be furtherly applied to combine the pulsed lasers with lower repetition frequency and narrower pulse width. These results pave the way for large-scale CBC of high-power and high-quality pulsed fiber lasers.

In recent decades, metasurfaces have emerged as an exotic and appealing group of nanophotonic devices for versatile wave regulation with deep subwavelength thickness facilitating compact integration. However, the ability to dynamically control the wave–matter interaction with external stimulus is highly desirable especially in such scenarios as integrated photonics and optoelectronics, since their performance in amplitude and phase control settle down once manufactured. Currently, available routes to construct active photonic devices include micro-electromechanical system (MEMS), semiconductors, liquid crystal, and phase change materials (PCMs)-integrated hybrid devices, etc. For the sake of compact integration and good compatibility with the mainstream complementary metal oxide semiconductor (CMOS) process for nanofabrication and device integration, the PCMs-based scheme stands out as a viable and promising candidate. Therefore, this review focuses on recent progresses on phase change metasurfaces with dynamic wave control (amplitude and phase or wavefront), and especially outlines those with continuous or quasi-continuous atoms in favor of optoelectronic integration.

Bovine serum albumin (BSA) microspheres were prepared through a facile and low-cost route including a high-speed dispersion of BSA in cross-linking solution followed by spray drying. Interestingly the as-prepared BSA microspheres possess unique blue-green, green, green-yellow, and red fluorescence when excited by specific wavelengths of laser or LED light. The studies of UV-visible reflectance spectra and fluorescence emission spectra indicated that four classes of fluorescent compounds are presumably formed during the fabrication processes. The formation and the potential contributors for the unique green and red autofluorescence were also discussed and proposed though the exact structures of the fluorophores formed remain elusive due to the complexity of the protein system. The effect of spray-drying conditions on the morphology of spray-dried samples was investigated and optimized. FTIR was further employed to characterize the formation of the functional groups in the as-prepared autofluorescent microspheres. Good in vitro and in vivo biocompatibility was demonstrated by the cytotoxicity test on the A549 cancer cells and tissue histological analysis, respectively. The autofluorescent BSA microspheres themselves were then applied as a novel tracer for convenient tracking/modeling of the biodegradation of autofluorescent BSA microspheres injected into mouse model based on noninvasive, time-dependent fluorescence images of the mice, in which experimental data are in good agreement with the proposed mathematical model. All these studies indicate that the as-developed protein microspheres exhibiting good biocompatibility, biodegradability, and unique autofluorescence, can significantly broaden biomedical applications of fluorescent protein particles.

An innovative electrochemical sensor was developed based on the modification of a glassy carbon electrode (GCE) surface with graphene oxide aerogel (GA) wrapped copper centered metal-organic framework (Cu-MOF) and was applied to the detection of trace catechol (CT). The morphology, structure of GA/Cu-MOF and electrochemical properties of GA/Cu-MOF/GCE were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemical techniques, respectively. GA/Cu-MOF/GCE has a wide linear range of 12.5–900 μmol∙L−1 (R2 = 0.997) and a low limit detection of 1.65 μmol∙L−1. Compared with the unmodified GCE, GA/Cu-MOF/GCE shows better stability, greater sensitivity and higher repeatability. Importantly, this new modified material was successfully prepared and used for the detection of trace amounts of catechol, providing a new idea for electrochemical detection.

High-efficiency optoelectronic devices require materials with suitable band gap, excellent carrier mobility, strong light-matter interaction, and high thermal- and photostability. Herein, we report two layered materials of group VI, namely, $\mathrm{Se}{\mathrm{S}}_{2}$ and $\mathrm{Te}{\mathrm{S}}_{2}$, which meet all those desired criteria. Both materials are stable with 1T-$\mathrm{Mo}{\mathrm{S}}_{2}$-like structure, and exhibit in-direct gap semiconducting feature and possess extraordinary electronic transport properties with isotropic carrier mobilities outperforming their $\mathrm{Mo}{\mathrm{S}}_{2}$ analog. Using the $GW$ approach for determining the quasiparticle electronic structure and Bethe-Salpeter equation accounting for the many-body excitonic effects, the optical properties of both materials have been identified. We find that exciton effects are significant in both materials that is characterized by the large binding energy of 0.66 and 0.84 eV for monolayer $\mathrm{Se}{\mathrm{S}}_{2}$ and $\mathrm{Te}{\mathrm{S}}_{2}$, respectively. The absorption edges lie in the optimal energy window of $1.0\text{--}1.5\phantom{\rule{0.28em}{0ex}}\mathrm{eV}$, which enables strong photoabsorption covering the whole visible-light region. Finally and importantly, we demonstrate that the in-direct nature of those materials can be violated by capping them with 2H-$\mathrm{Mo}{\mathrm{S}}_{2}$ to form a van der Waals heterostructure, while keeping the gap in the energy favorable region. Those physical and optical characteristics make few-layer $\mathrm{Se}{\mathrm{S}}_{2}$ and $\mathrm{Te}{\mathrm{S}}_{2}$ highly appealing for room-temperature light-emitting devices and, particularly, solar harvesting devices.

We present a nanoparticle size-separation device based on a nanofluidic rocking Brownian motor. It features a ratchet-shaped electrostatic particle potential with increasing barrier heights along the particle transport direction. The sharp drop of the particle current with barrier height is exploited to separate a particle suspension into multiple sub-populations. By solving the Fokker--Planck equation, we show that the physics of the separation mechanism is governed by the energy landscape under forward tilt of the ratchet. For a given device geometry and sorting duration, the applied force is thus the only tunable parameter to increase the separation resolution. For the experimental conditions of 3.5 V applied voltage and 20 s sorting, we predict a separation resolution of $\sim 2$ nm, supported by experimental data for separating spherical gold particles of nominal 80 and 100 nm diameters., 5 pages, 4 figures plus supplemental material

A novel layer by layer (LbL) assembled structure with phosphorylcholine groups was fabricated to improve the hemocompatibility of paclitaxel/chitosan (PTX/CS) nanofibers (NF) coatings The random copolymers with phosphorylcholine groups poly (2‑methacryloyloxy-ethylphosphorylcholine‑co‑methacrylicacid) (PMAs) were synthesized through free radical polymerization and then first PMA layer formed on PTX/CS NF coatings via electrostatic interactions. After that CS polycation and PMA polyanion thin films LbL formed on PTX/CS NF coatings. The LbL structure was confirmed by X-ray photoelectron spectroscopy (XPS) and water contact angle. The drug release in vitro indicated that the PMA modified PTX/CS NF coatings (PTX/CS-PMA NF coatings) showed a sustained slower release of PTX drug. The LbL coatings containing phosphorylcholine groups could significantly reduce proteins adsorption, platelets adhesion and cell adhesion. They showed a lower platelet (about 6%) and protein (30–40%) (bovine serum albumin, BSA; bovine plasma fibrinogen, Fg) adhesion. Meanwhile, the adhesion of human umbilical vein endothelial cells (HUVECs) was also found reduced. These results demonstrate that the preparation of PMA modified coatings is a simple strategy to improve the hemocompatibility of PTX/CS NF coatings, has good potential for application in blood-contacting materials and devices. Statement of significance We develop a simple method to improve the hemocompatibility of paclitaxel/chitosan (PTX/CS) nanofibers (NF) coatings, which can significantly reduce the protein adsorption, and the adhesion of cells and platelets. Using layer by layer (LbL) assembly with PMA polyanion and CS polycation, multilayered PMA/CS films formed on the PTX/CS NF coatings. The X-ray photoelectron spectroscopy (XPS) and water contact angle characterization demonstrated that a cell outer membrane mimetic structure was formed on the PTX/CS NF coatings. The hemocompatibility of modified surface was significantly improved as shown by 94% adhesion suppression for platelets and 60–70% adsorption suppression for bovine plasma fibrinogen (Fg) and bovine serum albumin (BSA). The drug release in vitro indicated that the PMA modified PTX/CS NF (PTX/CS-PMA) coatings had a sustained drug release. Thus this paper provides a facile method for fabricating cell outer membrane mimetic structure which can improve hemocompatibility of blood-contacting material surfaces.

Tungsten-based coatings without TiC addition (TiC-free) and with 1.5 wt% TiC addition (TiC-doped) were fabricated by supersonic atmospheric plasma spraying (SAPS) technique, respectively. The as-sprayed coatings were then irradiated by laser. The results showed that the as-sprayed coatings were mainly composed of lamellar structure. TiC phase located mainly at lamellar gaps of the as-sprayed TiC-doped coating with a morphology of strip filled the gaps. The as-sprayed TiC-doped coating exhibited dense structure, lower porosity, reduced oxygen content and higher thermal conductivity as compared with the as-sprayed TiC-free coating. The as-irradiated coatings could be divided into remelted zone, un-remelted zone and/or mixing zone. Cracks were more easily formed in the as-irradiated TiC-free coating than in the as-irradiated TiC-doped coating. The stripped TiC phase in the as-sprayed TiC-doped coating changed into quasi-spherical/spherical ones in the remelted zone of the irradiated coating and distributed along the tungsten grain boundaries. The averaged tungsten grain size in the remelted zone of the as-irradiated TiC-doped coating was about 5.4 μm and that of the as-irradiated TiC-free coating was about 14.8 μm. There were about 96 wt% α(W) and about 4 wt% γ(W) existed in the remelted zone near the surface of the as-irradiated TiC-free coating. Only α(W) could be received in the remelted zone far from the surface of the as-irradiated TiC-free coating and the remelted zone of the as-irradiated TiC-doped coating. There were no obvious diffraction peaks for γ(W) could be indexed from the XRD patterns for the as-irradiated TiC-doped coating. The ability of the as-sprayed TiC-doped coating to resist laser irradiation was greater than the as-sprayed TiC-free coating, mainly attributing to the higher thermal conductivity of the as-sprayed TiC-doped coating and the refinement effect of TiC particles in the as-irradiated TiC-doped coating.

We propose an explicit surface-potential-based direct current (dc) model for fully depleted polysilicon (poly-Si) thin-film transistors (TFTs). Being analytical and explicit, the proposed model is a solid base for compact models of these devices. The essential for our model is the explicit calculation of the surface potential, using the Lambert W function. Subsequently, using the surface potential, we also develop the expressions for charge and current, employing well established approaches, which include integration of carrier’s charge for drain current. Furthermore, the solutions of surface potential and drain current were validated by numerical results and experimental data, respectively. Finally, we discussed in detail about the effects on the surface potential and dc properties from the full depleted poly-Si TFT parameters. As a result, such a model is suitable to be implemented into computer-aided simulations of both device and circuit designs, due to its high computational accuracy and efficiency.

High concentration p-type AlInP material is an important layer to achieve low resistant and large carrier confinement in short-wavelength red-light laser diodes (LDs). To investigate the Mg doping behavior and other characteristics in the red-light LDs with tensile GaInP well structure, two LDs wafers with different Mg-doped AlInP cladding layers were grown by the metalorganic chemical vapor deposition (MOCVD) method. Incorporation and activation behavior of Mg atoms in heavily-doped AlInP were analyzed by the comparisons between hole concentration and atom concentration. We demonstrate that it is possible to achieve hole concentration above 1018 cm−3 using Mg dopant in AlInP layers just by an in-situ annealing. Furthermore, a hole concentration as high as 2.92 × 1018 cm−3 was achieved after post rapid thermal annealing in the N2 atmosphere, which is the highest hole doping concentrations reported to-date for the p-AlInP material.

A series of functional CeBiO x nanofibers (NFs) with different Ce:Bi molar ratios were successfully prepared by a facile two-step synthetic procedure including electrospinning and calcination. After systematic characterization of their morphology and structure/composition using various advanced techniques, the as-synthesized CeBiO x NFs were employed to modify screen-printed electrodes (SPEs) for the determination of fever reliever/pain reducer drug acetaminophen (AP) via both cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The results showed that the electrocatalytic activity of CeBiO x NFs was heavily dependent on Ce:Bi molar ratio and the Ce 0.75 Bi 0.25 O x NFs resulted in the highest electro-oxidation signal for AP among all Ce:Bi molar ratios tested in this study. Moreover, the Ce 0.75 Bi 0.25 O x NFs modified SPE showed a sensitivity of 360 μA mM −1 cm −2 , a low detection limit of 0.2 μM (signal to noise ratio of 3), a wide linear range up to 130 μM for DPV-based AP detection, and good intra- and inter-electrode reproducibility. Both the selectivity against uric acid, glucose, dopamine, ascorbic acid and the accuracy of the developed sensor for real sample analysis were also investigated using commercial paracetamol tablets and AP-spiked human serum samples.

The reaction mechanism of selective catalytic reduction of NO with ammonia (SCR) on MnOx/TiO2 catalysts was investigated through experiments and density functional theory (DFT) calculation. Firstly, the catalytic performance of catalyst with different molar ratios of MnOx/TiO2 was investigated and then was analyzed by NH3 temperature programmed desorption (NH3-TPD). The crystalline structure and the valence state of the MnOx/TiO2 catalyst were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). According to the results, the model of MnOx/TiO2 was established. Secondly, the different active sites of catalyst surface and adsorption characteristics of reacting gases during the SCR reaction based on in-situ DRIFT was investigated. Finally, the energy of different elemental reaction and isomerization of intermediate was calculated by MS Dmol3. It was found that the main active substance of catalyst was Mn4+ species which distributed dispersedly on the catalyst surface. The introduction of MnOx dopant can promote the adsorption of gas and reduce the formation energy of oxygen vacancy. The complete catalytic cycle goes in three steps: (a) Lewis acid site reaction follows Eley-Rideal mechanism; (b) Bronsted acid site reaction follows Langmuir-Hinshelwood mechanism; (c) Regeneration of catalyst.

Bi2X3 (X = S, Se, and Te) binary compounds have been widely studied as thermoelectric materials and reference topological insulators. Replacing one of the X atoms with a different atom Y of the same group has resulted in a new family of ternary compounds Bi2X2Y (X, Y = O, S, Se, and Te), which have attracted increasing attention very recently. By means of first-principles calculations within density functional theory, we have systematically studied the geometric structures and electronic properties of the whole family of these ternary compounds. We find that these compounds can be divided into two major groups. The first is traditional semiconductors, which include (i) Bi2O2Y, (ii) Bi2S2Y, and (iii) Bi2OY2. The other is topological insulators, which are (i) Bi2Se2Y and (ii) Bi2Te2Y. The optimized lattice parameters, band gaps as well as effective masses are in excellent agreement with recently available experimental measurements. In particular, we have found a new semiconductor material Bi2S2Te, which possesses an orthorhombic structure in space group pnma with a moderate direct gap of 0.5 eV at the HSE06 level and a small hole effective mass (∼0.22m0), which should favour fast hole transport and deserves further experimental studies. This work provides a road map for the exploration of the fundamental properties of the ternary compounds in this family as well as for their practical applications at the device level.

A physics-based drain current compact model for amorphous InGaZnO (a-InGaZnO) thin-film transistors (TFTs) is proposed. As a key feature, the surface potential model accounts for both exponential tail and deep trap densities of states, which are essential to describe a-InGaZnO TFT electrical characteristics. The surface potential is solved explicitly without the process of amendment and suitable for circuit simulations. Furthermore, based on the surface potential, an explicit closed-form expression of the drain current is developed. For the cases of the different operational voltages, surface potential and drain current are verified by numerical results and experimental data, respectively. As a result, our model can predict DC characteristics of a-InGaZnO TFTs.

A physics-based compact model for double-gate polysilicon thin-film transistors (TFTs) with a doped channel is proposed in this paper. Through the effective charge density approach, the electrostatic potential is solved explicitly from the Poisson’s equation without using the conventional regional approach. The resulting single-piece electrostatic potential equation, which does not consist of the intermediate parameter, offers clear physics meaning and good accuracy, particular when the TFT operates in the transition region. The TFT’s drain current model is then developed by integrating the electrostatic potential equation analytically with the Pao-Sah equation. Finally, the model is verified by numerical and experimental data. Such a compact model is highly suitable for circuit simulations.

Nanomicelles, by virtue of their prominent biocompatibility, degradability, and ability to solubilize hydrophobic drugs, have been widely used as the most effective delivery platform for anticancer drugs. However, undesirable drug-loading capacity, unfeasible modification, poor in vivo stability, and intratumoral penetration remain to be addressed. Herein, we introduce a novel core/shell PEGylated poly(glycerol sebacate) (PEGS)/hydroxyapatite (HA) hybrid nanomicelle based on a unique triblock PEGS substrate with functional carboxyls in terminals and free hydroxyls as pendant groups. The hydrophobic doxorubicin (DOX) can be controllably encapsulated in the core of nanomicelles via hydrogen bonding, and ensuing in situ mineralization of HA occurs as a shell layer with the electrostatic effect between the carboxylate radical (COO-) and calcium ion (Ca2+). Through optimizing the coordination of PEGS nanomicelles and HA mineralization, 20-30 nm spherical nanoparticles can be formed with considerable drug loading (0.38 mg DOX/1 mg nanoparticles) and a sensitive pH-responsive release (about 50% release amount at pH 5.6 while

InP quantum dots (QDs) are considered as one of the most promising candidates of Cd- or Pb-based QDs in the applications of display and lighting. However, the performances of blue InP QDs and the corresponding light emitting devices (LEDs) are far inferior to those of their red and green counterparts, which strongly limits the development of InP QD based LEDs (QLEDs) technology. Here, high quantum yield (∼81%) and large size (∼7.0 ± 0.9 nm) InP/GaP/ZnS//ZnS QDs with a thick shell have been successfully synthesized by a shell engineering approach, and the corresponding QLEDs exhibit a record brightness and external quantum efficiency of 3120 cd·m-2 and 1.01%, respectively. Large-scale density functional theory calculations on thousands-of-atoms QDs indicate that thicker-shell ones favor a more balanced carrier injection in the QD film and simultaneously suppress the FRET between closely packed QDs, which collectively contribute to the improved blue device performances.

Nitrogen oxide (NOx) emissions have attracted much attention for increasing concern on the quality of the atmospheric environment. In view of NO decomposition in the cement production process, the preparation of Cu-Al/SiO2 porous material and its effect on NO decomposition were studied, and the denitrification mechanism was proposed in this paper. The NO decomposition performance of the Cu-Al/SiO2 porous material was tested via the experimental setup and infrared spectrometer and micro gas chromatography (GC). The result shows that the Cu-Al/SiO2 porous material with the template of cetyltrimethylammonium bromide (CTAB) had a better NO decomposition rate than materials with other templates when the temperature was above 500 &deg, C, and NO decomposition rate could approach 100% at high temperatures above 750 &deg, C. Structure analysis indicates that the prepared Cu-Al/SiO2 material structure was a mesoporous structure. The X-Ray Diffraction (XRD) and Ultraviolet&ndash, visible spectrophotometry (UV&ndash, Vis) results of the denitrification product show that the Cu-Al/SiO2 material mainly decomposed to Cu2O and Si2O, and the CuO decomposed to Cu2O and O2 at high temperature. The Cu(I)O was considered as the active phase. The redox process between Cu(II)O and Cu(I)O was thought to be the denitrification mechanism of the Cu-Al/SiO2 porous material.

Colloidal quantum dots (QDs) of group III-V are considered as promising candidates for next-generation environmentally friendly light emitting devices, yet there appears to be only limited understanding of the underlying electronic and excitonic properties. Using large-scale density functional theory with the hybrid B3LYP functional solving the single-particle states and time-dependent density functional theory accounting for the many-body excitonic effects, we have identified the structural, electronic, and excitonic optical properties of InP, GaP, and GaInP QDs containing up to a thousand atoms or more. The calculated optical gap of InP QD appears in excellent agreement with available experiments, and it scales nearly linearly with the inverse diameter. The radiative exciton decay lifetime is found to increase surprisingly linearly with increasing the dot size. For GaP QDs we predict an unusual electronic state crossover at a diameter of around 1.5 nm, whereby the nature of the lowest unoccupied molecular orbital (LUMO) state switches its symmetry from ${\mathrm{\ensuremath{\Gamma}}}_{5}$-like at a larger diameter to ${\mathrm{\ensuremath{\Gamma}}}_{1}$-like at a smaller diameter. After the crossover, the absorption intensity of the band-edge exciton states is significantly enhanced. Finally, we find that Vegard's law holds very well for GaInP random alloyed quantum dots down to ultrasmall sizes with less than a hundred atoms. The obtained energy gap bowing parameter of this common-cation compound in QD regime appears positive, size-dependent, and much smaller than its bulk parentage. The volume deformation, dominating over the charge exchange and structure relaxation effects, is mainly responsible for the QD energy gap bowing. The impact of excitonic effects on the optical bowing is found to be marginal. The present work provides a road map for a variety of electronic and optical properties of colloidal QDs in group III-V that can guide spectroscopic studies.

The biocompatibility and anticancer effect of hydroxyapatite nanoparticles (HAPNs) are compelling and promising in cancer nanomedicine. However, the essential role of fetal bovine serum (FBS) in a biological environment possibly determining the state of agglomeration and intracellular fate of HAPNs (length: ~ 60 nm; width: ~ 20 nm) has never been studied. Here, we investigated the importance of FBS in agglomeration and cell response of HAPNs in human osteosarcoma MG-63 cells. Protein adsorption on the surface of HAPNs after mixing with different concentrations of FBS was confirmed using transmission electron microscope (TEM), attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, quartz crystal microbalance with dissipation (QCM-D), and thermogravimetric analysis (TG). The adsorption of serum protein improved dispersed state and stabilization of HAPNs, which was evidenced by dynamic light scattering (DLS), inverted microscope, and scanning electron microscope (SEM). More specifically, the agglomerate size of HAPNs in cell culture medium without FBS was above 1400 nm, while the agglomerate size of HAPNs with 10% FBS was decreased to about 200 nm and maintained for at least five days. Meanwhile, serum protein adsorption on HAPN surface enhanced cellular uptake and anticancer efficacy of HAPNs in MG-63 cells.

Massive bleeding control and anti-infection are the major challenges for urgent trauma with deep and noncompressible hemorrhage in both clinic and battlefield. Inspired by the coordinated primarily blood clot formation and secondly coagulation cascade activation in natural hemostasis process, an injectable, quaternized hydroxyethyl cellulose/mesocellular silica foam (MCF) hydrogel sponge (QHM) for both hemorrhage control and antibacterial activities were prepared via one-pot radical graft copolymerization. The as-prepared QHMs exhibited instant water-triggered expansion and superabsorbent capacity and thereby effectively facilitated blood components concentration. Moreover, the QHM1 with appropriate amount of MCF (9.82 w/w %) could further activate the coagulation factors. Synergistically, the QHM1 could reduce the plasma clotting time to 59 ± 4% in vitro and showed less blood loss than commercially available hemostatics in vivo noncompressible hemorrhage models of lethal rabbit-liver defect. Furthermore, the QHM with a quaternary ammonium groups density of 2.732 mmol/g exhibited remarkable antibacterial activities and excellent cytocompatibility. With the efficient hemostasis efficacy and excellent antibacterial behavior, QHM dramatically facilitated the wound healing in a full-thickness skin defect model in vivo. Thus, this QHM represents a promising hemostatic in more widespread clinical application.

Photocatalytic reduction of Cr(Ⅵ) is a safe, economical and clean method. In this study, a series of photocatalysts based on N-I co-doped TiO2 supported on activated carbon (denoted as x/yNIT@AC-z, N-I/Ti = x/y, calcination temperature = z °C) were synthesized, characterized and utilized for Cr(Ⅵ) photocatalytic reduction. Results of characterization revealed that all the prepared TiO2 existed in the form of monocrystalline tetragonal anatase phase with the particle size of 20 nm. Among them, 1/2NIT@AC-350 exhibited the highest photocatalytic performance. 1/2NIT@AC-350 showed a narrow band gap of 2.77 eV, which was chiefly because of the role of defect levels caused by pentavalent iodine, interstitial and substitutional nitrogen. 1/2NIT@AC-350/UV light/citric acid system exhibited the complete removal of 50 mg/L Cr(Ⅵ), over four successive reuse cycles without any obvious decrease in its photocatalytic reduction capability. In addition, the activated carbon in 1/2NIT@AC-350 provided a high concentration reaction environment for TiO2 via electrostatic attraction, which makes the photocatalyst possess a strong photocatalytic reaction driving force even at low concentration. Cr(Ⅵ) was also successfully removed in an actual water matrix (Yangtze river). This study provides a promising demonstration for the treatment of environmental pollutants, especially for Cr(Ⅵ) in wastewater effluents.

Adopting a facile two-step hydrothermal method to fabricate an efficient hierarchical transition metal selenide MoSe2/CoSe2 nano-flakes (NFs) anchored on carbon fiber paper (CFP) as a high-efficiency electrocatalyst for hydrogen evolution reaction (HER). The morphology shows that the surface of CFP is uniformly covered by the abundant nanosheets. Benefitting from the hydrophilic, the nano-catalysts on the MoSe2/CoSe2@CFP can fully contact with water molecules and accelerate the electron transfer, therefore promoting the water splitting. The electrochemical measurement suggests that on condition that current density of 10 ​mA ​cm−2, this nanometer electrocatalytic material has only an overpotential of 137 ​mV (vs. the RHE), which is lower as compared to CoSe2 (398 ​mV), MoSe2 (461 ​mV) and CFP (595 ​mV). The Tafel slope of the nanocomposite is 55.9 ​mV dec−1, which is lower than CoSe2 (138.1 ​mV dec−1) and MoSe2 (175.9 ​mV dec−1). Furthermore, the self-supporting nanocomposite exhibits outstanding stability in alkaline solution.

The self-supporting electrocatalysts have been demonstrated more advantages than powder catalysts. Both metal-support interaction and support effect further exhibit that the substrate material has significant impact on the electrochemical performance of the catalysts. Herein, we introduce a nickel nanowires film (Ni-NNF), synthesized via hydrazine reduction under a magnetic field, as a conductive substrate. By comparing with common substrates (Ni foam, carbon cloth and carbon fiber paper), the as-fabricated Ni-NNF exhibits higher conductivity and provides more active sites, resulting in better hydrogen evolution reaction (HER) activities and excellent durability. Thus, employing this type of metal nanowires as substrate is expected to synthesize better electrocatalyst.

The increasing requirement for highly sensitive sensors has promoted the development of new functional nanomaterials and various signal amplification strategies. Due to 2 dimensional (2D) materials’ excellent features of large surface areas, structural diversity, and abundant exposed accessible active sites, 2D MOF nanosheets exhibit potential applications in biosensing. Here, an ultrathin micron-sized MOF sheets with good dispersibility and high stability were prepared. Furthermore, a novel label-free aptasensor for ochratoxin A (OTA) detection had been developed based on 2D MOF nanosheets. This sensing signal was amplified by signal amplification strategies containing DNA walker machine, enrichment of Mb signal and nanomaterials of 2D MOF nanosheets and Ag NPs. With the help of these signal amplification strategies, the detection of OTA was reached with a low detection limit (0.08 fg mL−1) and a wide linear rage (0.10 fg mL−1 – 1 μg mL−1). Additionally, the aptasensor exhibits excellent OTA sensing performances, for example, good stability, outstanding selectivity, excellent repeatability, and regenerability.

Herein, In-situ conversional mycelium-like metal phosphides-encapsulated N, P co-doped carbon nanotubes (CNTs) coating on the stainless steel mesh (PSD-SM) as self-supporting electrocatalyst was fabricated via solid-diffusion (SD) and phosphorization process, which was the first time to fabricated the “chainmail for catalysts” use stainless steel mesh worked as self-reaction template and electrode-base materilas. The in-situ transformational mycelium-like CNTs array structure greatly enhanced the specific surface area of steel mesh and the graphitized carbon layer coating with high capacitance increases the electrochemical active sites. And the subsequent phosphorization treatment further improved the intrinsic catalytic activity of the material. PSD-SM exhibits the low overpotential of 231 mV at 10 mA·cm−2 with a Tafel slope of 88 mV·dec−1 for OER and 172 mV at 10 mA·cm−2 with a Tafel slope of 125 mV·dec−1 for HER. Further more, there are only 1.77 V deliver potential for water electrolysis of PSD-SM at 10 mA·cm−2 and the kinetic mechanism of as-fabricated samples for HER and OER was analyzed by Tafel slope and other measurement. This report provides an promising method to prepare efficient and robust electrocatalytic materials based on steel mesh for practical application.

Three tensile GaInP quantum well laser diode wafers were grown in the same run by low-pressure metalorganic vapor phase epitaxy on GaAs substrates misoriented by 10°, 15°, and 22° toward (1 1 1)A respectively. The photoluminescence peak wavelength and intensity of the active region, the strain mismatch and the doping carrier concentration of the epitaxial layers, the whole thickness and the surface morphology of the wafers were all found to be strongly dependent on the misorientation of the substrates. Considering the comprehensive effects of material, electrical, and optical properties, the 15° substrate was superior to the 10° substrate for the growth of shorter wavelength red-light laser diode wafer, while substrate with too large misorientation of 22° was not a good choice for the epitaxy of red-light laser diode wafer.

The gate-leakage behavior in GaN-based high electron mobility transistors (HEMTs) is studied as a function of applied bias and temperature. A model to calculate this current is given, which shows that trap-assisted tunneling, trap-assisted Frenkel-Poole (FP) emission, and direct Fowler-Nordheim (FN) tunneling have their main contributions at different electric field regions. In addition, the proposed model clearly illustrates the effect of traps and their assistance to the gate leakage. We have demonstrated the validity of the model by comparisons between model simulation results and measured experimental data of HEMTs, and a good agreement is obtained.

Spherical nanosized hydroxyapatite (HA) was successfully synthesized via a water-in-oil microemulsion route at room temperature in short time. The effect of water-to-oil and water-to-surfactant ratios on the stability of microemulsion system was investigated to establish a stable reaction system, with span-80, cyclohexane and Ca(NO 3 ) 2 ·4H 2 O((NH 4 ) 2 HPO 4 ) solution as surfactant, oil phase, and water phase, respectively. Size and morphology change of obtained HA under optimal microemulsion system were further studied under various reaction time and temperature, and a possible growth mechanism was proposed. A moderate reaction temperature of 25 °C and reaction time of 5 h facilitated the formation of spherical HA particles in the dimension of 70 nm with good uniformity and regularity, which served as a great candidate in biomedical applications.

ZnO nanofibers (ZnO NFs) were fabricated by electrospinning a dimethylformamide solution of zinc acetate containing polyvinylpyrrolidone and polymethylmethacrylate binary polymer matrix, followed by calcination. The obtained ZnO NFs are composed of close-packed ZnO nanoparticles of ca.20 nm in diameter. With Nafion acting as adhesive, the ZnO NF coated glassy carbon electrode (ZnO NF/GCE) has been prepared and applied as a new sensing platform for heavy metal determination with square wave stripping voltammetry. The high surface area and the strong affinity to cadmium (Cd) render the ZnO NF/GCE sensitive to Cd ion measurement. The experiment parameters were optimized by the design of orthogonal experiment. Under the optimal conditions, the current response exhibits a good linear relationship with the concentration of Cd(II) ranging from 4.8 × 10 −9 to 1.3 × 10 −6 mol L −1 ,with the detection limit of 1.8 × 10 −9 mol L −1 (S/N > 3). The developed sensor has been successfully applied for the determination of Cd(II) in water sample. The simultaneous analysis of Cd(II), Pb(II), Cu(II) and Hg(II) has been demonstrated to be feasible.

Lung cancer is the leading cause of cancer-related mortality worldwide. Most patients have metastases at the time of diagnosis, thus demanding development of more effective and specific agents. In this study, the specific anticancer effect of hydroxyapatite nanoparticles (HAPNs) to human lung cancer cells (A549) and the underlying mechanisms were investigated, using normal bronchial epithelial cells (16HBE) as the control. Rod-shaped HAPNs (∼10 nm in width and 50 nm in length) were prepared by aqueous precipitation method. Without any further functionalization and drug loading, HAPNs selectively inhibited cancer-cell proliferation. Their efficient mitochondrial targeting correlated strongly with decreased mitochondrial membrane potential and induction of mitochondria-dependent apoptosis in A549 cells. Caveolae-mediated endocytosis via lysosome trafficking was observed to be a prominent internalization pathway for HAPNs in both A549 and 16HBE cells. However, more nanoparticles were taken up into A549 cells. HAPNs triggered a sustained elevation of intracellular calcium concentration ([Ca2+]i) in cancer cells but only a transitory increase in normal control cells. In a nude mouse lung cancer model with xenotransplanted A549 cells, HAPN treatment demonstrated nearly 40% tumor growth inhibition without apparent side effect. These results demonstrated that the enhanced cellular uptake and mitochondrial targeting of HAPNs, together with the prolonged elevation of [Ca2+]i in A549 cells, could result in the cancer-specific cytotoxicity of HAPNs. Thus, HAPNs might be a promising agent or mitochondria-targeted delivery system for effective lung cancer therapy.

Precipitate phases in a reduced activation ferritic/martensitic steel CLAM (HEAT-0912) were observed and analyzed using transmission electron microscopy and energy dispersive spectroscopy. The steel samples were normalized at 980 °C for 30 min and then tempered at 760 °C for 90 min followed by an air cooling. Through the selected-area electron diffraction pattern analyses and energy dispersive X-ray data, eight kinds of precipitate phases were identified to be Ta-rich MX carbonitride with a f.c.c. crystal structure, Ta-rich M3X2 carbonitride with a base-centered monoclinic crystal structure, Ta-rich MSi2 phase with a hexagonal structure, V-rich MX carbonitride with a f.c.c. crystal structure, V-rich M2C carbide with an orthorhombic-simple crystal structure, Cr-rich M23C6 carbide with a f.c.c. structure, Cr-Ta-rich M7C3 carbide with an orthorhombic-simple crystal structure, Cr-rich M6C carbide with a f.c.c. structure, respectively. There appear to have no previous reports of the Ta-rich MSi2, Ta-rich M3X2, V-rich M2C and Cr-rich M6C phases identified in reduced activation ferritic/martensitic steels.

To explore high-efficiency, 1ow-cost and durable non-precious metal electrocatalysts for hydrogen evolution reaction (HER) in alkaline media, the binder free molybdenum carbide@ nickel foam (Mo2C@NF-x, x represents the calcination temperature) electrodes were synthesized by the hydrothermal and calcination process. Using glucose as the carbon source for the fabrication of Mo2C is not only environmental friendly but also promotes the formation of nanospheres and improves the dispersibility of the catalysts. The carbon shell formed by calcination also can improve the electron transfer between Ni foam substrate and nanospheres. Furthermore, the carbon shell can act as “armour for catalyst”, protecting the Mo2C from the harsh conditions (e.g., strong acidity or alkalinity) and improving the stability of the catalysts during electrocatalysis. The optimal electrocatalyst is Mo2C@NF-850, which only needs overpotential of 42 ​mV for hydrogen evolution reaction to reach 10 ​mA ​cm−2, a small Tafel slope of 76 ​mV·dec−1, as well as satisfactory durability in 1.0 ​M KOH electrolyte for HER.

We report a linear-cavity mode-locked Yb-doped fiber laser using self-made semiconductor saturable absorber mirrors (SESAMs). The SESAMs are grown by means of metalorganic chemical vapor deposition, with a design of high modulation depth using strain-compensated multiple quantum wells. We choose two kinds of self-made SESAMs with different periods of top reflector in the linear cavity, and they can both be applied to stable mode-locking operation without damage. The output characteristics of the mode-locked oscillator indicate that SESAMs with high modulation depth are beneficial for mode-locked fiber lasers and the modulation depth can limit the pulse width of the output pulses.

We report on the design and fabrication of high power density vertical-cavity surface-emitting laser (VCSEL) with ring close packing structure (RCP) emitting at 808 nm. The RCP-VCSELs with a broad area of 100 μm in diameter contains seven-small-mesas sharing the same super-cavity, and the oxide-aperture diameters of each small mesa was 20 μm. A detailed theoretical analysis is conducted with the help of a thermoelectric model and far-field model. The current density distribution and temperature characteristics were improved. The RCP-VCSELs with maximum power density of 3.73 kW/cm2, slope efficiency of 1.1 W/A, and overall wall-plug efficiency (WPE) of 35% have been realized from the broad area of 100 μm in diameter. An improved transverse-mode emission performance featuring a low beam divergence of FWHM (3.3°) and a stable temperature tolerance of the studied device shows the potential of our approach. It is anticipated that this work will provide an effective strategy for the fabrication of high performance large-area VCSELs with good beam quality under ambient and harsh conditions.