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The slippery liquid infused porous surface has developed into a potential technology to solve the problem of poor durability in corrosion resistance. Herein, a kind of slippery liquid infused porous surface is created on 7075 aluminum alloy by wire electrical discharge machining for corrosion resistant applications. The hardness of the constructed porous microstructure is similar to the aluminum alloy substrate material, which ensures the stability of the slippery liquid infused porous surface. The modification of low surface energy substance fluorosilane avoids the direct contact between corrosive liquid and porous surface, and improves the lyophobic performance of the porous microstructure surface. The corrosion resistance of the porous microstructure surface is enhanced by the injection of perfluorinated lubricating oil. The experimental results show that the created slippery liquid infused porous surface can display super-slippery properties and durable corrosion resistance. The average sliding velocity of a water droplet is 0.48 ± 0.05 mm s−1 at a sliding angle of 5°. The corrosion current density of the surface is 3.116 × 10−6 A cm−2, which is 2 orders of magnitude lower than that of the polished surface. And the impedance radius reaches 90 kΩ cm2, which is about 20 times that of the polished surface.

A new strategy to achieve long-lived room temperature phosphorescence performance has been developed via the formation of a donor–acceptor structure in a coordination polymer, which features a lifetime (40.22 ms) three orders of magnitude higher than that of pristine phosphor. It also shows remarkable angle-dependent polarized emission.

We designed an efficient self-quenching fluorescence probe and constructed this probe-mediated exponential isothermal amplification system for miRNA detection. Owing to the significant improvement in the detective signal-to-background ratio, a wide dynamic range of 9 orders of magnitude and a limit of detection as low as 0.08 aM can be easily achieved in a single step. Furthermore, benefiting from the additional advantages of high specificity and biocompatibility, the proposed method has been demonstrated to be capable of accurately quantifying miRNA biomarkers in serum, which will provide promising perspectives for clinical diagnosis.

The results of experimental and computational studies to identify the reasons for the increase in the vibration transmission through compensators of pipelines with liquid by several orders of magnitude with increasing frequency are considered. The descriptions of the found physical and computational models of this phenomenon are given. The results of experimental studies carried out on a special stand to study the possibility of reducing this transmission in a wide range of oscillation frequencies from 10 to 300 Hz by an order of magnitude or more by means of passive and active vibration damping methods are given. It has been shown experimentally that in the case of active spatial damping of dynamic forces behind the compensator, the mutual influence of the damping channels can significantly change the efficiency of the system.

Microfluidic paper-based analytical devices (μPADs) are foundational devices for point-of-care testing, yet suffer from limitations in regards to their sensitivity and capability in handling complex assays. Here, we demonstrate an airflow-based, evaporative method that is capable of manipulating fluid flows within paper membranes to offer new functionalities for multistep delivery of reagents and improve the sensitivity of μPADs by 100-1000 times. This method applies an air-jet to a pre-wetted membrane, generating an evaporative gradient such that any solutes become enriched underneath the air-jet spot. By controlling the lateral position of this spot, the solutes in the paper strip are enriched and follow the air jet trajectory, driving the reactions and enhancing visualization for colorimetric readout in multistep assays. The technique has been successfully applied to drive the sequential delivery in multistep immunoassays as well as improve sensitivity for colorimetric detection assays for nucleic acids and proteins via loop-mediated isothermal amplification (LAMP) and ELISA. For colorimetric LAMP detection of the COVID-19 genome, enrichment of the solution on paper could enhance the contrast of the dye in order to more clearly distinguish between the positive and negative results to achieve a sensitivity of 3 copies of SARS-Cov-2 RNAs. For ELISA, enrichment of the oxidized TMB substrate yielded a sensitivity increase of two-to-three orders of magnitude when compared to non-enriched samples - having a limit of detection of around 200 fM for IgG. Therefore, this enrichment method represents a simple process that can be easily integrated into existing detection assays for controlling fluid flows and improving detection of biomarkers on paper.

Control of conductance through a single molecule via alternating anchoring points provides a unique perspective to design single-molecule electronic devices. A high conductance difference among different states is essential for a single-molecule electronic device, which is challenging due to restriction of the structural changes in single-molecule junctions. Here, tetraphenylethylene derivatives with multiple anchoring sites are designed and synthesized to investigate single-molecule conductance using the scanning tunneling microscope break junction (STM-BJ) technique. In the break-junction cycle process, connection conformations with different anchor sites have been achieved reversibly to switch single-molecule conductance using the STM-BJ technique. Through mechanical control, these multi-anchored single-molecule junctions can achieve up to three conductance switching cycles, and the variation in conductance reaches up to four orders of magnitude. Theoretical calculations reveal that the conductance change originates from the different connecting sites and the different anchored configurations of single-molecule junctions provide a significantly different transmission. Our findings provide a reliable strategy to manipulate the mechanical switching and shed light on investigating the intrinsic charge transport of multi-anchored molecules.

Hybrid quantum optomechanical systems offer an interface between a single two-level system and a macroscopical mechanical degree of freedom. In this work, we build a hybrid system made of a vibrating microwire coupled to a single semiconductor quantum dot (QD) via material strain. It was shown a few years ago, that the QD excitonic transition energy can thus be modulated by the microwire motion. We demonstrate here the reverse effect, whereby the wire is set in motion by the resonant drive of a single QD exciton with a laser modulated at the mechanical frequency. The resulting driving force is found to be almost 3 orders of magnitude larger than radiation pressure. From a fundamental aspect, this state dependent force offers a convenient strategy to map the QD quantum state onto a mechanical degree of freedom., Comment: 16 pages, 12 figures

Optical immunoassays require measurement systems capable of distinguishing the light from the laser source, used to illuminate the assay, from the light generated by the particles contained within the assay itself (fluorescence). The main challenge is that the light used to excite the sample is several orders of magnitude more intense than that generated by fluorescence. Usually, single junction photodiodes and optical filters are used. The sensitivity of these schemes is limited by the filter performance. In this work, the design of a CMOS integrated circuit including buried double junction photodiodes (BDJ) is presented. This approach allows the measurement of both light sources simultaneously. From simulations, it is shown that this integrated circuit with BDJ would achieve a better detection limit than the scheme based on single-junction photodiodes of equivalent silicon area. Furthermore, integrating the photodetectors and the reading circuit on the same chip would make the system suitable to be used in biomedical applications such as Point-of-Care (POC) devices., Los inmunoensayos ópticos requieren de sistemas de medición capaces de distinguir la luz de la fuente láser, utilizada para iluminar el ensayo, de aquella generada por las partículas contenidas en el mismo (fluorescencia). El principal desafío es que la luz usada para excitar la muestra es varios órdenes de magnitud más intensa que la generada por fluorescencia. Usualmente, se utilizan filtros ópticos y fotodiodos de juntura simple. La sensibilidad de estos esquemas se encuentra limitada por el desempeño del filtro. En este trabajo se presenta el diseño de un circuito integrado de lectura que incorpora fotodiodos de doble juntura, lo que permite la medición de ambas fuentes de luz en simultáneo. A partir de simulaciones, se demuestra que este enfoque lograría un mejor límite de detección que el esquema basado en fotodiodos de juntura simple de igual área. Además, la integración del circuito de lectura y los fotoreceptores en un mismo chip, favorecería la miniaturización y portabilidad del sistema para aplicaciones biomédicas como en dispositivos Point-of-Care (POC).

Transition-metal dichalcogenide heterostructures are an emergent platform for novel many-body states from exciton condensates to nanolasers. However, their exciton dynamics are difficult to disentangle due to multiple competing processes with time scales varying over many orders of magnitude. Using a configurable nano-optical cavity based on a plasmonic scanning probe tip, the radiative (rad) and nonradiative (nrad) relaxation of intra- and interlayer excitons is controlled. Tuning their relative rates in a WSe2/MoSe2 heterobilayer over 6 orders of magnitude in tip-enhanced photoluminescence spectroscopy reveals a cavity-induced crossover from nonradiative quenching to Purcell-enhanced radiation. Rate equation modeling with the interlayer charge transfer time as a reference clock allows for a comprehensive determination from the long interlayer exciton (IX) radiative lifetime τIXrad = (94 ± 27) ns to the 5 orders of magnitude faster competing nonradiative lifetime τIXnrad = (0.6 ± 0.2) ps. This approach of nanocavity clock spectroscopy is generally applicable to a wide range of excitonic systems with competing decay pathways.

A concept of the optimal design of a silicon waveguide based on optically coupled Mie-resonant nanoantennas for efficient inputting of light from point emitters associated with excitons localized at defects in a thin InSe film is proposed. Numerical calculations demonstrate that the efficiency of coupling between a dipole emitter and a resonant silicon waveguide is four orders of magnitude greater than that for a conventional ridge waveguide.

Experimental results of measuring the threshold power density of stimulated emission in coumarin-30 dye solutions with ZnO nanoparticles upon irradiation with femtosecond laser pulses are presented. It is shown that the stimulated emission thresholds of coumarin-30 dye solutions with incorporated ZnO nanoparticles upon irradiation with femtosecond laser pulses are approximately by 3 orders of magnitude higher than the stimulated emission thresholds of coumarin-30 dye solutions with incorporated ZnO nanoparticles irradiated with nanosecond laser pulses.

Nanocrystalline BiFeO3-based powder materials with an average crystallite size near 40 nm have been prepared by solution combustion synthesis from bismuth and iron nitrates using sucrose and tartaric acid as fuel. The materials have been characterized by X-ray diffraction, helium pycnometry, scanning electron microscopy, energy dispersive X-ray microanalysis, and Mossbauer spectroscopy. Magnetometry results demonstrate that the magnetic response of the materials varies over several orders of magnitude, depending on the synthesis procedure.

The development of high-performance glucose sensors is an urgent need, especially for diabetes mellitus diagnosis. However, the glucose monitoring is conventionally operated in an invasive finger-prick manner and their noninvasive alternatives largely suffered from the relatively poor sensitivity, selectivity, and stability, resulted from the lack of robust and efficient catalysts. In this paper, we design a concave shaped nitrogen-doped carbon framework embellished with single Co site catalyst (Co SSC) by selectively controlling the etching rate on different facet of carbon substrate, which is beneficial to the diffusion and contact of analyte. The Co SSC prompts a significant improvement in the sensitivity of the solution-gated graphene transistor (SGGT) devices, with three orders of magnitude better than those of SGGT devices without catalysts. Our findings expand the field of single site catalyst in the application of biosensors, diabetes diagnostics and personalized health-care monitoring.

The efficiency of the laser-induced desorption method as a detector of hydrogen isotopes under pulsed laser irradiation (wavelength 1064 nm, 100 mJ, duration 10 ns) for different power densities of incident radiation on deuterium-saturated thin titanium films was investigated. When the power flow density increases by 16 times, the intensity of the thermal desorption peak increases by more than 2 orders of magnitude. Long-term repeated irradiation of the surface does not lead to significant depletion of the content of hydrogen isotopes in the studied layers, allowing their further ex-situ analysis.

Ion-exchange membranes are critical components of hydrogen fuel cells, where these ionomers can be confined to nanoscale thicknesses, altering the physical properties of these films from that of bulk membranes. Therefore, it is important to develop methods capable of measuring and elucidating the transport mechanisms under thin film confinement compared to bulk Nafion. In this study, water sorption and diffusion in a Nafion thin film were measured using time-resolved in situ polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS). Interfacial mass transport limitations were confirmed to be minimal, while restricted water diffusion was observed, where the effective diffusion coefficient of water in the thin Nafion film was many orders of magnitude lower (between 4 and 5 orders of magnitude) than those reported for bulk membranes and was dependent on the initial hydration state of the Nafion. Furthermore, the response of the hydrophobic domains (Teflon backbone) to the swelling of the hydrophilic domains (ionic clusters) was shown to be orders of magnitude slower than that of bulk Nafion.

Lisää oa-julkaisu, kun saatavilla. A sensitive photoacoustic detection approach employing a silicon cantilever is investigated for power measurement of electromagnetic radiation. The technique which is actuated by pressure waves generated through radiation-induced heat depicts high sensitivity for a considerably large spectral range from 325 nm to 1523 nm. The implemented method shows linear response in the measurement of radiation power from 15 nW to 6 mW demonstrating a dynamic range of almost six orders of magnitude. A numerical model has been developed to analyze and optimize the measurement sensitivity. The model allows studying different dimensions of the cantilever which is one of the key components of the radiation detection process. The numerical results are in good agreement with experimental results. The electromagnetic power detection technique shows future potential for industrial applications and scientific studies.

The canine olfactory system is a highly efficient and intricate tool often exploited by humans for detection for its many attributes, including impressive sensitivity to trace analyte vapors. Canine detectors are often touted as having lower limits of detection, or olfactory detection threshold (ODT), than other field-relevant detection technologies; however, previous attempts to quantify canine ODTs have resulted in reported estimates spanning multiple orders of magnitude, even for the same analyte. A major contributor to these discrepancies is the vapor delivery method used for testing, where losses due to adsorption and dilution are often unaccounted for, and the presence of unattended compounds in the vapor stream due to carryover may go unnoticed. In this research, a trace vapor generator (TV-Gen) was used to deliver quantitatively accurate amounts of vapor reproducibly over time for canine testing. Analyte losses due to adsorption to surfaces in the flow path, dilution in the sniff port at the outlet, and analyte carryover were considered. Computational fluid dynamic (CFD) modeling was used to visualize analyte vapor spread throughout the port. CFD simulations revealed the need for a diffuser to encourage the diffusion of the analyte throughout the port. As a result, the modified vapor generator provides analyte air as a diffuse flow that is evenly distributed through the custom sampling orifice, as opposed to a narrow stream of air at the chosen concentration which exits directly into the environment. Laboratory validations were carried out for three analytes, amyl acetate, 2,4-dinitrotoluene (DNT), and methyl benzoate. A linear response across more than two orders of magnitude vapor concentration range was achieved for all analytes. These efforts will be applied in further research utilizing this TV-Gen vapor delivery system for canine ODT testing, eliminating many quantitative changes seen previously. Graphical abstract.

Scaling information bits to ever smaller dimensions is a dominant drive for information technology (IT). Nanostructured phase change material emerges as a key player in the current green-IT endeavor with low power consumption, functional modularity, and promising scalability. In this work, we present the demonstration of microwave AC voltage induced phase change phenomenon at ∼3 GHz in single Sb2Te3 nanowires. The resistance change by a total of 6-7 orders of magnitude is evidenced by a transition from the crystalline metallic to the amorphous semiconducting phase, which is cross-examined by temperature dependent transport measurement and high-resolution electron microscopy analysis. This discovery could potentially tailor multistate information bit encoding and electrical addressability along a single nanowire, rendering technology advancement for neuro-inspired computing devices.

Experimental results showed that the effective thermal conductivity of silicon nanowire is smaller than the bulk thermal conductivity, while that of carbon nanotube (CNT) is usually much larger than its bulk counterpart. In order to resolve this paradox, a nonlocal heat conduction model for one-dimensional materials is proposed. This nonlocal model indicates that the different heat conduction boundary conditions of silicon nanowire and CNT lead to the different behaviour of their thermal conductivities in comparison with their bulk counterparts. Furthermore, the nonlocal effect of heat flux on the surfaces of the CNT makes the thermal conductivity of the single-wall CNT more than seven orders of magnitude higher than its bulk thermal conductivity. The thermal conductivities of the single-wall and multi-wall CNTs obtained by using the nonlocal model show an agreement with the experimental ones.

Atomic force microscopy is employed in the experimental study of specific features of the field emission of electrons from a single silicon needle-type cathode to quasi-vacuum (air). Noncontact regime of the atomic force microscopy is used to measure the I–V characteristics of a single cathode with nanometer-scale tip radius at distances of 10 and 20 nm between the cathode tip and the measurement probe. Electric field distributions are simulated for both surface of the tip of a single cathode and tip surfaces of single cathodes in an array, and the results are used to theoretically estimate electric field enhancement versus cathode–probe distance. It is shown that the enhancement factor calculated from the experimental I–V characteristics in the Fowler–Nordheim coordinates is greater than the result of theoretical calculations by several orders of magnitude. This circumstance indicates that additional quantum dimensional effects that play an important role in the generation of the electron emission current in the nanoscale gap must be taken into account.

Last decade has seen tremendous progress in the development of nanoparticle dispersion based volumetrically absorbing solar thermal systems. However, for these systems to compete with their surface absorption counterparts, it is imperative to reach an optimum receiver design. Optimization in turn necessitates accurate modeling of highly coupled transport phenomena involved in these systems. The present work represents a significant step ahead in this direction, wherein, a comprehensive and mechanistic theoretical framework is developed which is robust enough to account for coupled transport phenomena and orders of magnitude of operating parameters for a host of receiver design configurations. Moreover, equivalent surface absorption based systems are also modeled to provide a comparison between volumetric and surface absorption processes under similar operating conditions. Finally, the present work serves to define optimal performance domains of these solar thermal systems, particularly in the laminar flow regime (100

Graphene foam (GF)—a three-dimensional network of hollow graphene branches—is a highly attractive material for diverse applications. However, to date, the heat dissipation characteristics of GFs have not been characterized. To fill this gap, we synthesized GF devices, subjected them to high temperatures, and investigated their thermal behavior by using infrared microthermography. We find that while the convective area of GF devices is comparable to that of bulk materials (such as metals), the coefficient of convection of these devices is several orders of magnitude higher than that of metals. In addition, the GF devices showed a reproducible thermal behavior, which we attribute to negligible temperature-induced morphological changes (as confirmed by Raman analysis). Taken together, our findings suggest GF as a promising candidate material for advanced cooling applications where efficient heat dissipation is needed, e.g., in electrical circuits.

The rate-determining step of the photoelectrochemical (PEC) water splitting is the water oxidation reaction at the photoanode, which is 4 orders of magnitude slower than the water reduction reactio...

A broadband photodetector with high performance is highly desirable for the optoelectric and sensing application. Herein, we report a "photo-thermo-electric" (PTE) detector based on an ultrathin SnTe film. The (001)-oriented SnTe films with the wafer size scale are epitaxially grown on the surface of sodium chloride crystals by a scalable sputtering method. Due to the giant PTE effect under laser spot excitation on the asymmetric position between two terminals, a built-in electrical field is produced to drive bulk carriers for a self-powered photodetector, leading to a broad spectral response in the wavelength range from 404 nm to 10.6 μm far beyond the limitation of the energy band gap. Significantly, the photodetector displays a high on/off photoswitching ratio of over 105 with a suppressed dark current, which is 4-5 orders of magnitude higher than that of other reported SnTe-based detectors. Under zero external bias, the device yields the highest detectivity of ∼1.3 × 1010 cm Hz1/2 W-1 with a corresponding responsivity of ∼3.9 mA W-1 and short rising/falling times of ∼78/84 ms. Furthermore, the photodetector transferred onto the flexible template exhibits excellent mechanical flexibility over 300 bending cycles. These findings offer feasible strategies toward designing and developing low-power-consumption wearable optoelectronics with competitive performance.

Summary Experiments are often used to produce emulators of deterministic computer code. This article introduces composite grid experimental designs and a sequential method for building the designs for accurate emulation. Computational methods are developed that enable fast and exact Gaussian process inference even with large sample sizes. We demonstrate that the proposed approach can produce emulators that are orders of magnitude more accurate than current approximations at a comparable computational cost.

In this paper, three dimensional spherical magnetic field coils are proposed and optimized for atomic sensors that require highly uniform magnetic field coils within a limited volume. The design objective of the uniform coil is transformed into a nonlinear optimization model with constraints, which is solved by combining with the particle swarm optimization algorithm. Compared with the traditional cylindrical tri-axial magnetic field coil system whose volume is limited by the aspect ratio of the coil structure, the three dimensional spherical coils not only effectively reduce the volume but also provide consistent magnetic field performance in the three coordinate axis directions. It is of great significance to the miniaturization of atomic sensors. The theoretical calculation shows that the uniformity of spherical coil is improved by about 2 to 3 orders of magnitude compared with the Lee-Whiting coil and the saddle coil. The measurements show that the magnetic field uniformity of our design reached $1.5\times 10^{-4}$ along the ${z}$ -axis within a range of $\pm 0.25{R}$ . The actual magnetic field distribution is basically consistent with the theory. However, due to the limited processing and experimental conditions, the actual magnetic field uniformity is 1 to 2 orders of magnitude lower than the theory.

In recent years, current-sensing dc-SQUIDs have enabled the application of noise thermometry at ultralow temperatures. A major advantage of noise thermometry is the fact that no driving current is needed to operate the device and thus the heat dissipation within the thermometer can be reduced to a minimum. Such devices can be used either in primary or relative primary mode and cover typically several orders of magnitude in temperature extending into the low microkelvin regime. Here we will review recent advances of noise thermometry for ultralow temperatures.

Freestanding polystyrene thin films were found to reach elongations 2 orders of magnitude larger than what is found in bulk tests. We performed planar tensile testing at multiple strain rates using...

The detection of harmful volatile organic compounds is of great significance to environmental quality and human health. However, it still remains a challenge to achieve high detection sensitivity at a relatively low temperature. Herein, an ultrasensitive catalytic sensor for the detection of triethylamine (TEA) based on ZnO/PtO/Pt nanoarray thin films was realized. Sensor measurements reveal that the PtO/Pt sensitizer dramatically reduces the working temperature from 195 °C of a pristine ZnO sensor to 125 °C of ZnO/PtO/Pt sensors. The ZnO/PtO/Pt sensors exhibit an extremely high response of 3513 to 50 ppm TEA, which is three orders of magnitude higher than that of pristine ZnO. Meanwhile, an ultralow limit of detection of 8.3 ppb is achieved. The outstanding performances are superior to those in most previous reports on TEA detection. Mechanistic investigations reveal that the outstanding performances are ascribed to the strong electronic interaction between PtO and ZnO and the catalytic spillover effect of Pt.

Metal–insulator transition materials such as VO2 have garnered much attention in the field of neuromorphic devices because of their nonlinear behavior and orders of magnitude scale property changes...

Overcoming the sub-5 nm gate length limit and decreasing the power dissipation are two main objects in the electronics research field. Besides advanced engineering techniques, considering new material systems may be helpful. Here, we demonstrate two-dimensional (2D) subthermionic field-effect transistors (FETs) with sub-5 nm gate lengths based on ferroelectric (FE) van der Waals heterostructures (vdWHs). The FE vdWHs are composed of graphene, MoS2, and CuInP2S6 acting as 2D contacts, channels, and ferroelectric dielectric layers, respectively. We first show that the as-fabricated long-channel device exhibits nearly hysteresis-free subthermionic switching over three orders of magnitude of drain current at room temperature. Further, we fabricate short-channel subthermionic FETs using metallic carbon nanotubes as effective gate terminals. A typical device shows subthermionic switching over five-to-six orders of magnitude of drain current with a minimum subthreshold swing of 6.1 mV/dec at room temperature. Our results indicate that 2D materials system is promising for advanced highly-integrated energy-efficient electronic devices.

The volumetric concentration of hydrogen in two Brazilian diamonds is determined using secondary ion mass spectrometry and implantation of hydrogen into an external standard sample (with a dose of 1 × 16 at/cm2 and energy of 120 KeV). The diamonds studied differ noticeably in their intensities of IR-active hydrogen from 0 to 1.5 cm–1 according to the analyses of their IR spectra. The results demonstrate that for both samples studied, the volumetric concentration of hydrogen does not exceed the reached detectable level of (1–2) × 1018 at/cm3 or 1.7–3.3 at. ppm; i.e., it is lower by an order of magnitude than in the early chemical analysis and by 2–3 orders of magnitude lower than the results of the ion-beam spectrochemical, nuclear-physical, and ERDA analyses. Only a part of the hydrogen forms optically active impurities in diamond crystals and can be determined by spectral methods.

Ce and W co-doped CaBi2Nb2O9 ceramics with chemical formula Ca0.96Ce0.04Bi2Nb2-xWxO9 (CCBN-W100x, x = 0–0.07) are fabricated via conventional solid state sintering method, to investigate the effect of W addition on the structure, electrical resistivity, dielectric and piezoelectric properties. A piezoelectric constant d33 of 13.4 pC/N is obtained in CCBN-W2 ceramics, >100% higher than that of pure CaBi2Nb2O9 (d33 = 5.8–6.4 pC/N). Of particular significance is that the electrical resistivity of CCBN-W2 ceramics (ρ = 3.7 × 109 Ω cm at 500 °C) is three orders of magnitude higher than pure CaBi2Nb2O9 (ρ = 2.9 × 106 Ω cm at same temperature). All these properties, together with its low dielectric loss (tanδ = 0.13%) and excellent d33 thermal stability up to 800 °C, merit the CCBN-W2 ceramics for high temperature piezoelectric sensing applications.

Terahertz (THz) electromagnetic waves strongly interact with complex molecules, making THz spectroscopy a promising tool for high-sensitivity molecular detection, especially for biomedical applications. Metamaterials are typically used for enhancing THz-molecule interactions to achieve higher sensitivities. However, a primary challenge in THz molecular sensing based on metallic metamaterials is the limited tunability of optical constants of metals. Here, we present an ultrahigh-sensitivity molecular sensor based on carbon nanotube (CNT) THz metamaterials. The sensor, consisting of a CNT cut-wire array on a Si substrate prepared by a novel two-step method, exhibits a reflectance resonance whose frequency strongly varies with the substrate composition, geometries of periodic arrays, and analyte composition. We used this sensor to detect glucose, lactose, and chlorpyrifos-methyl molecules, achieving limit-of-detection values of 30, 40, and 10 ng/mL (S/N = 3), respectively, higher than that of metallic metamaterials by 2 orders of magnitude. We attribute this ultrahigh sensitivity to the high conductivity of CNTs and the efficient adsorption of the target analyte by CNTs through van der Waals forces and π-π stacking. These easy-to-fabricate CNT-based THz metamaterials pave the way for versatile and reliable ultrahigh-sensitivity THz molecular detection.

Memristor devices that can operate at high speed with high density and nonvolatile capabilities have great potential for the development of high data storage and robust wearable devices. However, in real-time, the performance of memristors is challenged by their instability toward harsh working conditions such as high temperature, extreme humidity, photo irradiation, and mechanical bending. Herein, we introduce a TaOx/AlN-based flexible and transparent memristor device having stable endurance under extreme 2 mm bending (for more than 107 cycles) with an ON/OFF ratio of more than 2 orders of magnitude at 25 ns rapid switching. This device exhibits excellent flexibility under extreme bending conditions (bending radius of 2 mm) even with intense ultraviolet (UV) radiation. A thin AlN insertion layer having low dielectric and high thermal conductivity plays a crucial role in improving the switching stability and device flexibility. In particular, the devices exhibit excellent minimum switching fluctuations under UV irradiation, >106 s nonvolatility retention at high temperature (135 °C), various gas ambient, and damp heat test (humidity 95.5%, 83 °C) because of the indium metal drift during the switching process and high bonding energy of Ta–O. Most importantly, direct observation of indium metal strongly anchored in the TaOx switching layer during the switching process is reported for the first time via transmission electron microscopy, which provides clear insights into the switching phenomenon. Furthermore, the results of electrical and material analyses explain that our facile device design has excellent potential for wearable and aerospace applications.

Additive manufacturing permits innovative soft device architectures with micron resolution. The processing requirements, however, restrict the available materials, and joining chemically dissimilar components remains a challenge. Here we report silicone double networks (SilDNs) that participate in orthogonal crosslinking mechanisms—photocurable thiol-ene reactions and condensation reactions—to exercise independent control over both the shape forming process (3D printing) and final mechanical properties. SilDNs simultaneously possess low elastic modulus (E100%, Additive manufacturing processing requirements pose restrictions on materials and joining chemically dissimilar components. Here the authors use silicone double networks that participate in orthogonal crosslinking mechanisms for independent control of the shape forming process and final mechanical properties.

In the nonrelativistic approximation of fluctuation electrodynamics, using the specular reflection model and the nonlocal dielectric permittivity of a metal, simple analytical expressions are obtained for the friction forces in the particle-plate and plate-plate configurations at relative motion of bodies with constant velocity. It has been shown that at distances of about 1–10 nm, for an Au nanoparticle (or a gold plate) moving near another similar plate at rest, the dissipative forces are 2–4 orders of magnitude higher than when using the Drude local dielectric function.

Oxidation behavior of boron-containing HfC/SiC nanocomposites (SHBC) at temperatures up to 1500 °C and with exposure time up to 100 h was investigated. Two strategies to improve the oxidation resistance of the HfC/SiC ceramics are proposed. First concept involves the incorporation of a small amount of boron (ca. 0.6 wt.%) into the nanocomposite via a single-source-precursor approach, which contributes significantly to the enhancement of its oxidation resistance. Parabolic oxidation rate constants of 10−3 to 10-4 mg2/(cm4 h) at 1300−1500 °C were measured for SHBC and were several orders of magnitude lower than those recorded for boron-free HfC/SiC. The second improvement concept is realized via passivation of the samples upon short-term oxidation at 1400 °C, providing an excellent oxidation resistance over a wide temperature range. This is a crucial step especially when considering the poor oxidation behavior of HfC and the sluggish formation of protective silica scale at moderate temperatures.

We report an ambipolar phototransistor using the organic–inorganic hybrid perovskite, CH3NH3PbI3 [methylammonium lead iodide (MAPbI3)]. The high iconicity of MAPbI3 leads to intrinsic p-type and n-type self-doping, which enables simultaneous or selective hole and/or electron transport in a single device, depending on the bias conditions. Under white light illumination, both hole and electron current increase by four orders of magnitude and the dark characteristics recover completely and immediately after turning off the light source. In addition, the photosensitivity can be controlled by compositional ratio (MAI:PbI2) and the thickness of the MAPbI3 film. Moreover, the hole current shows higher responsivity and shorter response time (0.62 A/W and 100 ms) compared with electron current (0.20 A/W and 200 ms), resulting in respective photodetectivity values of $6.87\times 10^{15}$ and $1.33\times 10^{15}$ Jones. These photodetectivities are among the highest reported, making the phototransistors reported herein suitable for simple and cost-effective optoelectronics.

Liquids typically form droplets when exiting a nozzle. Jets––cylindrical streams of fluid—can form transiently at higher fluid velocities, yet interfacial tension rapidly drives jet breakup into droplets via the Rayleigh–Plateau instability. Liquid metal is an unlikely candidate to form stable jets since it has enormous interfacial tension and low viscosity. We report that electrochemical anodization significantly lowers the effective tension of a stream of metal, transitioning it from droplets to long (long lifetime and length) wires with 100- [Formula: see text] m diameters without the need for high velocities. Whereas surface minimization drives Rayleigh–Plateau instabilities, these streams of metal increase in surface area when laid flat upon a surface due to the low tension. The ability to tune interfacial tension over at least three orders of magnitude using modest potential (

This is the first report on the enhanced thermoelectric (TE) properties of novel reaction-temperature (TRe) and duration-induced Bi2S3-Bi nanocomposites synthesized using a facile one-step polyol method. They are well characterized as nanorod composites of orthorhombic Bi2S3 and rhombohedral Bi phases in which the latter coats the former forming Bi2S3-Bi core-shell-like structures along with independent Bi nanoparticles. A very significant observation is the systematic reduction in electrical resistivity ρ with a whopping 7 orders of magnitude (∼107) with just reaction temperature and duration increase, revealing a promising approach for the reduction of ρ of this highly resistive chalcogenide and hence resolving the earlier obstacles for its thermoelectric application potentials in the past few decades. Most astonishingly, a TE power factor at 300 K of the highest Bi content nanocomposite pellet, made at 27 °C using ∼900 MPa pressure, is 3 orders of magnitude greater than that of hot-pressed Bi2S3. Its highest ZT at 325 K of 0.006 is over twice of that of similarly prepared CuS or Ag2S-based nanocomposites. A significantly improved TE performance potential near 300 K is demonstrated for these toxic-free and rare-earth element-free TE nanocomposites, making the present synthesis method as a pioneering approach for developing enhanced thermoelectric properties of Bi2S3-based materials without extra sintering steps.

This paper describes hydrothermally synthesized ZnSe nanoparticles for resistive-type relative humidity sensors. The structural, optical and morphological characterization of synthesized ZnSe nanoparticles was analyzed by means of x-ray diffraction, UV–vis spectroscopy, Fourier transform infrared spectroscopy, photoluminescence and transmission electron microscopy. Also, the details of the fabrication process and humidity sensing mechanism are described. The considerable sensitivity, response and recovery time is achieved due to enhanced electron transfer capability of ZnSe nanoparticles. The film resistance changes with relative humidity (RH) for approximately three orders of magnitude (109–106) over the range of 20–100% RH shows reasonably good sensitivity. This indicates the promising applications of ZnSe nanoparticles for room temperature environmental monitoring. Further, the response and recovery time, repeatability and reproducibility of the humidity sensors are also measured.

Nanocrystalline cobalt oxide Co3O4 and composite ZnO/Co3O4 are obtained by chemical deposition from solutions followed by thermal annealing. It is shown that the presence of zinc oxide particles during synthesis radically changes the mechanism of the cobalt carbonates growth, which leads to a change in the phase composition, morphology, and properties of the material. The resistivity of the conducting layers formed from composite ZnO/Co3O4 is three orders of magnitude lower than the resistivity of Co3O4 layers, and composite ZnO/Co3O4 gas sensors demonstrate much higher gas sensitivity than that of control cobalt oxide sensors.

A combination of conventional calorimetry, ultra-fast scanning calorimetry and resistive heating gives access to heating rates exceeding 6 orders of magnitude allowing to probe crystallization kinetics and mechanisms in a Cu-Zr-Al metallic glass. Continuous-heating-transformation and double-peak time-temperature-transformation diagrams are constructed and related to the formation of glass–crystal composites with enhanced ductility. The metastable B2-CuZr phase becomes dominantly formed at a heating rate of ~102 K s−1 and higher. A critical heating rate to bypass crystallization is ~10,000 K s−1. For isothermal annealing at >850 K, only one crystallization event is detected; for lower temperatures, a complex two-step transformation occurs.

The performance of a micro-acousto-fluidic device designed for microparticle trapping is simulated using a three-dimensional (3D) numerical model. It is demonstrated by numerical simulations that geometrically asymmetric architecture and actuation can increase the acoustic radiation forces in a liquid-filled cavity by almost 2 orders of magnitude when setting up a standing pressure half wave in a microfluidic chamber. Similarly, experiments with silicon-glass devices show a noticeable improvement in acoustophoresis of 20-μm silica beads in water when asymmetric devices are used. Microparticle acoustophoresis has an extensive array of applications in applied science fields ranging from life sciences to 3D printing. A more efficient and powerful particle manipulation system can boost the overall effectiveness of an acoustofluidic device. The numerical simulations are developed in the COMSOL Multiphysics® software package (COMSOL AB, Stockholm, Sweden). By monitoring the modes and magnitudes of simulated acoustophoretic fields in a relatively wide range of ultrasonic frequencies, a map of device performance is obtained. 3D resonant acoustophoretic fields are identified to quantify the improved performance of the chips with an asymmetric layout. Four different device designs are analyzed experimentally, and particle tracking experimental data qualitatively supports the numerical results.

It is shown that the free path of plasmon polaritons propagating along the interface between a metal and a crystal may be greatly increased (up to several orders of magnitude) by the choice of a certain crystal orientation that provides complete delocalization of the polaritons. As an example, a theory is developed for the interface between a metal and a uniaxial crystal with its optical axis parallel to the interface, both considered as semi-infinite media.

Luminescence lifetime imaging (LLIM) holds great promise in biomedical research owing to its excellent sensitivity and remarkable temporal–spatial resolution, but the development of effective long-lived luminescent probes for LLIM remains an unmet need. Herein, we designed two water-dispersible europium-doped nanoparticles (Eu-D1 and Eu-D2 NPs) for cellular LLIM, showing intense red luminescence emission and an increased lifetime of 4 orders of magnitude (∼56 000 times) than undoped NPs, which could be attributed to the multiple manipulations of their aggregation states, including efficient Forster resonance energy transfer (FRET), suppressed self-quenching, and restrained solvent effects. With good bioavailability, the as-developed NPs were demonstrated as reliable candidates for long-lifetime imaging agents. Such a simple and versatile strategy could be extended to develop various luminescent nanoprobes for advanced high-precision bioimaging.

Electron-beam irradiation (EBI) is an effective approach to engineer defects for two-dimensional (2D) materials. However, a detailed understanding of the effects of EBI on charge transport of 2D materials is still lacking. Herein, the value of source-drain current of monolayer MoS2 transistors can be largely improved by about 3 orders of magnitude under EBI, from 5 nA to 24.6 μA at 2 V bias voltage. In addition, a room-temperature mobility (μ) as high as ~ 83 cm2 V−1 s−1 was achieved when the device was irradiated for 80 s with a 10 kV accelerating voltage (~ 5.5% sulphur vacancies), far exceeding (about 80 times) that of the untreated device. The improvements of electrical properties after EBI are mainly attributed to the introduction of electrons and the enhanced charge transport channels. The charge transport behaviour under EBI exhibits variable range hopping associated with temperature. Our findings provide an avenue for building high performance electronics based on 2D materials.

Application of conducting ferroelectric domain walls (DW) as functional elements may facilitate development of conceptually new resistive switching devices. In a conventional approach, several orders of magnitude change in resistance can be achieved by controlling the DWs density using super-coercive voltage. However, a deleterious characteristic of this approach is high-energy cost of polarization reversal due to high leakage current. Here, we demonstrate a new approach based on tuning the conductivity of DWs themselves rather than on domain rearrangement. Using LiNbO3 capacitors with graphene, we show that resistance of a device set to a polydomain state can be continuously tuned by application of sub-coercive voltage. The tuning mechanism is based on the reversible transition between the conducting and insulating states of DWs. The developed approach allows an energy-efficient control of resistance without the need for domain structure modification. The developed memristive devices are promising for multi-level memories and neuromorphic computing applications.

Nicotine-containing electronic cigarette liquid (e-liquid) is prohibited in many countries, creating requirements for rapid detection approaches for on-site inspection or screening for large amounts of samples. Here, we demonstrate a simple way to identify nicotine using surface-enhanced Raman scattering (SERS) with substrates made of silver nanoparticle arrays imbedded in anodic aluminum oxide nanochannels (Ag/AAO). Compared with the reported colloidal nanoparticle-based SERS, that required serial dilutions to enable colloid aggregation in the viscous e-liquid, a small amount of undiluted e-liquid sample can be directly added onto our solid-phase Ag/AAO substrate without any pre-treatment. The sensitivity of our SERS measurements is 2-3 orders of magnitude higher than that required for identification of nicotine in e-liquid, which is typically around 1000-18,000 ppm. Using such nanoparticle array-based SERS, we have tested 22 commercially available e-liquid products, using the corresponding gas chromatography-mass spectrometry (GC-MS) reports as the reference. The SERS measurements were done within one hour and successfully identified 20 samples. Only 2 samples showed SERS interference from ingredients that were not suitable for SERS analysis.