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The present study proposes a segmented cooling-stream injection structure based on a certain coolant mass flow rate, and numerically investigates the effect of segmented cooling-stream injection on supersonic film cooling. The results indicate that without shock-wave impingement and with helium as the coolant, segmented cooling-stream injection can reduce the mixing between the mainstream and the cooling stream to produce better cooling performance than single injection, especially at larger coolant Mach numbers. However, with nitrogen as the coolant, the cooling effect of the segmented-injection system is very close to that of the single-injection system. Mixing at the impinging region is enhanced significantly when there is an incident shock wave. When the shock wave impinges between the two coolant inlets, segmented cooling-stream injection improves film cooling effectiveness in the midstream and downstream regions more than single injection because only part of the cooling stream undergoes the enhanced mixing effect of the shock wave. The advantage of segmented injection is reduced when the impinging region is behind the second coolant inlet. The further downstream the impinging region, the smaller the associated advantage.

In the broad application of tunable devices, the temperature stability of the dielectric tunable performance of ceramics should be considered. In this work, (1-x)Ba(Zr0.36Ti0.64)O3–x(Ba0.82Ca0.18)TiO3 (BZ0.36T–xBC0.18T) ceramics, where x = 0.3–0.7, were prepared by the solid-state high-temperature method. The combined effects of Ca2+ and Zr4+ ions on the microstructure of BZ0.36T–xBC0.18T ceramics were observed. The crystal structure was analyzed through X-ray diffraction, showing a pure perovskite ABO3-type structure, indicating the formation of a BCZT solid solution. High dielectric tunability (nr > 85% at

Due to the scarcity of indium (In) in the earth and its potential harm to individuals, the development of In-free transparent conductive film is considered crucial. In this work, In-free SnO2:Sb/Au/SnO2:Sb (ATO/Au/ATO, SAS) tri-layer films with high transparency and conductivity were successfully prepared on polycarbonate (PC) substrates by RF and DC magnetron sputtering at room temperature. The influence of the Au layer thickness on microstructure, electrical and optical performances was systematically studied after fixing the ATO thickness to 50 nm. It was indicated by X-ray diffraction patterns that ATO is amorphous and Au is oriented along (111). The trend of increasing and then decreasing light transmission with Au layer thickness was observed in both experimental and simulation results. The improved figure of merit (FoM, 1.89 × 10−2 Ω−1) was achieved in SAS tri-layer film, the resistivity and average transmittance of which was lowered to 7.50 × 10−5 Ω cm and 81.4%, respectively, when Au layer thickness is 11 nm. Moreover, the mechanism of the variation of optical and electrical properties at different Au layer thickness was proposed. Particularly, the SAS tri-layer films also exhibit superior flexibility, durability and adhesion. These results demonstrate SAS tri-layer films are promising alternative to ITO in flexible electronics applications.

Strain and stress play an important role in functional materials, but they are often neglected in electroceramics. Here we report the stress effect on microwave dielectric loss in rutile-related (Ti0.6Zr0.4)0.8(Zn1/3Nb2/3)0.2O2 solid solutions. The macroscopic, microscopic and nano-scale residual stresses have been systematically investigated, including their relationships. The average Raman spectra have demonstrated considerable macro-residual stresses, especially for the heavily cracked sample. The high-resolution Raman images reveal the inhomogeneity of residual stress distribution at the grain-level, which is reflected by the shifts of Raman-active modes. The high-resolution transmission electron microscope (HRTEM) images and geometric phase analysis (GPA) analysis show the aggregation of dislocations and resulting distortion of crystal. It can be found that the dielectric loss depends strongly on residual stresses, that samples with greater residual stress exhibit much higher dielectric loss because the residual stress increases the vibration anharmonicity of the lattice.

Precise determination of atomic structures in ferroelectric thin films and their evolution with temperature is crucial for fundamental study and design of functional materials. However, this has been impeded by the lack of techniques applicable to a thin-film geometry. Here we use cryogenic scanning transmission electron microscopy (STEM) to observe the atomic structure of a BaTiO3 film on a (111)-SrTiO3 substrate under varying temperatures. Our study explicitly proves a structure transition from a complex polymorphic nanodomain configuration at room temperature transitioning to a homogeneous ground-state rhombohedral structure of BaTiO3 below ∼250 K, which was predicted by phase-field simulation. More importantly, another unexpected transition is revealed, a transition to complex nanodomains below ∼105 K caused by an altered mechanical boundary condition due to the antiferrodistortive phase transition of the SrTiO3 substrate. This study demonstrates the power of cryogenic STEM in elucidating structure-property relationships in numerous functional materials at low temperatures.

Zn-air batteries are promising energy storage and conversion systems to replace the conventional lithium-based ones. However, their applications have been greatly hindered by the formation of Zn dendrites and ZnO passivation layer on the Zn anodes. Herein, we report the fabrication of an artificial protective layer comprised of N-doped threedi-mensional hollow porous multi-nanochannel carbon fiber with well-dispersed TiO2 nanoparticles (HMCNF). The incorporated TiO2 nanoparticles and N dopants improve the ion flux distribution and promote the surface adsorption, facilitating the interfacial pseudocapacitive behaviors during Zn deposition. The hierarchical architecture also induces homogenous electric field distribution at the anode/electrolyte interface. Accordingly, the deposition behavior of Zn is regulated, giving rise to enhanced utilization and rechargeability of Zn. When integrated in alkaline Zn-air batteries, the HMCNF-coated Zn anodes exhibit improved electrochemical performances relative to those with the bare Zn anodes, demonstrating a versatile strategy to boost energy storage of metal anodes through optimizing surface adsorption properties.

Based on the relationship of dipole formation and charge compensation, we prepared BaTiO3-based (x%MnO2-0.05%Nb2O5–BaTiO3, x%Mn–Nb-BT) ceramics using a solid-phase reaction in air and a reducing atmosphere. The influences of MnO2 doping and sintering atmospheres on crystal structure, charge compensation and dielectric properties were comprehensively studied. The ion substitution mechanism, solid solubility, and crystallinity of x%Mn–Nb-BT ceramics in different atmospheres were resolved by X-ray diffraction (XRD) and electron paramagnetic resonance (EPR) spectroscopy. X-ray photoelectron spectroscopy (XPS) showed that the percentages of oxygen vacancy and Ti3+ in this system were both affected by MnO2 doping and the atmosphere due to the reducibility of Mn4+ and the reducing atmosphere. Thus, the influence of doped MnO2 and the atmosphere on dipole formation and charge compensation was deeply discussed. These results provide further insight into the important role of MnO2 in improving the anti-reduction performance of BT-based ceramics.

Advanced sensors provide new opportunities to improve the understanding of soil properties and processes. One such sensor is the thermo-TDR sensor, which combines the functions of heat pulse probes and time domain reflectometry probes. Recent advancements in fine-scale measurements of soil thermal, hydraulic, and electrical properties with the thermo-TDR sensor enable measuring soil state variables (temperature, water content, and ice content), thermal and electrical properties (thermal diffusivity, heat capacity, thermal conductivity, and bulk electrical conductivity), structural parameters (bulk density and air-filled porosity) and fluxes (heat, water, and vapor) simultaneously. This chapter describes the theory, methodology, and potential applications of the thermo-TDR technique.

A silicon cantilever-based fiber-optic acoustic sensor (FOAS) is presented in this work. A rectangular cantilever is fabricated upon a silicon-on-insulator (SOI) wafer using a micro-electro-mechanical system (MEMS). The length, width and thickness of the silicon cantilever are $530~\mu \text{m}$ , $200~\mu \text{m}$ and $3~\mu \text{m}$ , respectively. The resonant frequency of the silicon cantilever is 14820 Hz with a sensitivity of 950 nm/Pa. An ultra-high speed absolute cavity length demodulation method is adopted using a complementary metal oxide semiconductor (CMOS) spectrometer and an 850 nm superluminescent light emitting diode (SLED). A modified Buneman frequency estimation and total phase demodulation algorithm is adopted. The frequency response curve shows a relatively flat trend from 20 Hz to 13 kHz. The sensor exhibits good linearities at different frequencies while the applied acoustic pressure is increased from 0 Pa to 2.5 Pa. Experimental results indicate that the minimum detectable pressure (MDP) of the proposed FOAS is calculated to be $25.68~\mu $ Pa/Hz1/2 at the frequency of 13 kHz. The silicon cantilever-based FOAS achieves broad operating bandwidth, high sensitivity, small size, and good stability.

Dielectric tunable properties in ferroelectric ceramics have been optimized by a variety of approaches, e.g., isovalent/aliovalent substitution, system composite et al., while the study of non-stoichiometric regulation on the performance of BCZT ceramics was rarely concerned. Herein, a series of novel non-stoichiometric (Ba0·91Ca0.09)x (Zr0·18Ti0.82)O3 (BCZTx) ceramic specimens were successfully prepared via solid-state reaction. The microstructures of BCZTx ceramics are simultaneously investigated through XRD and SEM. The diffuse phase transition (DPT) behaviour of BCZTx ceramics are studied by the Lorentz-type empirical formula. The significant enhancement of DPT behaviour is observed at x = 1.03, which probably due to the coaction of the generation of partial Schottky defects and prominent reduction of grain size. Furthermore, a high tunability (k) 87.80%, low dielectric loss (tan δ) 0.141%, and a remarkably enhanced FOM of 623 are achieved in x = 0.99 at a low DC bias electric fields (BEFs) of 7.28 kV/cm and room temperature (RT), which is superior to that of the stoichiometric BCZT ceramics and other available reported BT-based ceramics systems in term of the dielectric tunable properties. Meanwhile, it shows that the temperature dependent CQF value of x = 0.99 remained advantageous around the RT. These findings suggested that non-stoichiometric BCZTx ceramics with x = 0.99 are significantly competitive in the applications of dielectric tunable devices at RT. The non-stoichiometric regulation is an effective approach in improving the dielectric tunability properties of BCZT ceramics.

The top-performing perovskite solar cells (efficiency > 20%) generally rely on the use of a nanocrystal TiO2 electron transport layer (ETL). However, the efficacies and stability of the current stereotypically prepared TiO2 ETLs employing commercially available TiO2 nanocrystal paste are far from their maximum values. As revealed herein, the long-hidden reason for this discrepancy is that acidic protons (∼0.11 wt %) always remain in TiO2 ETLs after high-temperature sintering due to the decomposition of the organic proton solvent (mostly alcohol). These protons readily lead to the formation of Ti–H species upon light irradiation, which act to block the electron transfer at the perovskite/TiO2 interface. Affront this challenge, we introduced a simple deprotonation protocol by adding a small amount of strong proton acceptors (sodium ethoxide or NaOH) into the common TiO2 nanocrystal paste precursor and replicated the high-temperature sintering process, which wiped out nearly all protons in TiO2 ETLs during the sintering process. The use of deprotonated TiO2 ETLs not only promotes the PCE of both MAPbI3-based and FA0.85MA0.15PbI2.55Br0.45-based devices over 20% but also significantly improves the long-term photostability of the target devices upon 1000 h of continuous operation.

We have developed a 6-kA/cm² superconducting integrated circuit fabrication process toward large-scale single flux quantum digital circuits. To evaluate the process reliability and controllability, a set of process control monitors (PCMs) for monitoring fabrication and design parameters was designed and tested. Fabrication parameters, for example, film thicknesses and etched depths of the layers, were measured by testing specific patterns during fabrication. Design parameters such as the critical current density J c, normal-state resistance R n and actual sizes of Josephson junctions, the sheet resistance of Mo resistor R sh, and the penetration depth of Nb films were evaluated by electrically characterizing PCM circuits after fabrication. We also monitored superconducting critical currents for vias and Nb lines, and insulation properties between the metal layers systematically.

(Ba0.91Ca0.09)(Zr0.2Ti0.8)O3-2 mol% CuO + x mol% Li2CO3 ceramics are obtained at low sintering temperature (1100 °C) by solid-state reaction method to study the effect of Li2CO3 sintering additive on the structure, dielectric and tunable performance of (Ba0.91Ca0.09)(Zr0.2Ti0.8)O3-CuO ceramics. The XRD results suggest that Li+ occupies A site firstly (for x = 1 and 2) and then occupies B site (for x = 3 and 4). It brings to the variation of lattice structure, which results in the non-monotonic shift of Tm. The SEM shows that appropriate Li2CO3 sintering additive can promote the grain growth. The maximum average grain size obtained at x = 2 makes it possess a higher permittivity (8336) at room temperature and a larger tunability (48.03%) at a low bias electric field value of 7 kV/cm. Accompanied with its low tan δ (0.00286), a high FOM value of 167.95 is achieved. These results suggest that the prepared ceramics are more attractive to be used as tunable devices due to its low sintering temperature and high FOM at a low bias electric field.

We have developed a fabrication technology for superconducting integrated circuits with Nb-based Josephson junctions. The standard fabrication process with 10 mask levels includes 3 Nb superconducting layers and a Mo resistor layer. The influence of deposition parameters on film stress, electrical properties, and surface roughness were studied systematically. High quality Nb, Al, Mo, and SiO2 films were successfully deposited for the subsequent fabrication of circuits. The circuit fabrication started with the fabrication of Mo resistors with a target sheet resistance R sh of 2 Ω, followed by the deposition of Nb/Al-AlO x /Nb trilayer Josephson-junction. The target critical current density J c was set at 6 kA/cm2. Small-scale circuits such as our standard library cells have been successfully fabricated and tested, confirming the capability of our fabrication technology for superconducting integrated circuits.

The gold deposits in the Jiaodong Peninsula constitute the largest gold mineralized province in China. The mineralization shows common characteristics in their tectonic setting, ore-forming fluid and metallogenic system. Sulfidation and fluid immiscibility are two important mechanisms controlling gold precipitation, both of which consume sulfur in the ore-forming fluids. The escape of H2S from the main ore-forming fluids and the decrease of total sulfur concentration not only lead to the efficient precipitation of gold, but also result in the crystallization of reducing minerals such as pyrrhotite and oxidizing minerals such as magnetite. Quartz solubility shows strong dependence on temperature, pressure, and CO2 content. The dependence of quartz solubility on pressure is weak at low temperatures, and progressively stronger at higher temperatures. Similarly, the temperature dependence of quartz solubility is relatively low at low pressures, but becomes gradually stronger at high pressures. The results of solubility modeling can constrain the dissolution and reprecipitation behavior of quartz in the ore-forming veins and the formation mechanism of different types of quartz veins. The multi-stage mineralization fluid activity resulted in the complex dissolution structure of quartz in the Jiaodong gold veins. Pyrite in the main metallogenic period in the Jiaodong gold deposits shows complex microstructure characteristics at single crystal scale. The trace elements (mainly the coupling of As- and Au-rich belt) and sulfur isotope composition also display a certain regularity. The As-rich fluids might have formed by the initial pulse of ore-forming fluids through As-rich metasedimentary strata, while the As-Au oscillation zone at the margin of pyrite grains is related to the pressure fluctuation caused by fault activity and the local phase separation of fluids. There is a temporal and spatial evolution of gold fineness in the Jiaodong gold deposits. Water/rock reaction (sulfidation) was the main ore-forming mechanism of early gold mineralization, forming relatively high fineness gold, while significant pressure drop in the shallow part accompanied by fluid phase separation promoted the late gold mineralization, forming low fineness gold. Under cratonic destruction setting, dehydration of the amphibolite and granulite facies metamorphic lower-crust resulted in the formation of Au-CO2-rich ore-forming fluids, which rose along the deep fault and secondary structure, and formed the largescale fault-controlled gold deposits in Jiaodong.

Dielectric tunable devices with improved overall tunability properties are in urgent demand for tunable applications. Hence, a series of Pb-free dielectric tunable ceramics based on (Ba1−xCax) (Zr0·18Ti0.82)O3 (abbreviated as BCZTx, x = 0.05–0.21, corresponding to BCZT05 to BCZT21) were carefully prepared using the traditional solid-state route in this work. The crystal structure, surface morphology, dielectric properties, and tunable performance of different BCZTx ceramics at room temperature (RT) were systematically studied. The temperature-dependent dielectric tunable performance was further investigated. The phase evolutions were co-confirmed by XRD and d e r d T -T curves. Interesting, high tunability (86.09%), together with a relatively low dielectric loss (~0.19% @7.42 kV/cm) were obtained in BCZT09 ceramics at 1 kHz, resulting in a giant figure-of-merit (FOM) of 448, which implied these ceramics are promising matrix for dielectric tunable applications that operated at RT. From the Tunability−T and FOM−T curves, it can be found that Ca2+ incorporation can improve the temperature stability of dielectric tunable performance to a certain extent. In addition, the FOM−T curve of BCZT09 showed advantages over other compositions in the temperature range of −20 °C–85 °C, and its maximum FOM (~886) was reached at 40 °C. These observations suggest the BCZT09 ceramic as a promising matrix for application in dielectric tunable devices operating at RT. This work may guide the design of novel high-performance tunable ceramic materials.

In this article, a tilted fiber Bragg grating (TFBG) plasmonic sensor based on thymine (T) - Hg - thymine (T) (T-Hg-T) base asymmetric pairing and Au nanoparticles (AuNPs), which can be used for highly sensitive and selective ultra-low-concentration Hg2+ detection, has been demonstrated. As is known, TFBG can provide an effective mean to easily excite the surface plasmon resonance (SPR) phenomenon while the fiber is coated with metal layer. By measuring the evolution of spectra, the SPR properties hence the surface perturbation could be detected accurately. To achieve highly sensitive and selective Hg2+ detection, the two specially designed single-strand probe DNAs (ssDNAs) with rich T base that can specifically forming stable T-Hg-T asymmetric pairing are served as a binding element for AuNPs labelled-target DNA conjugates. In the present of Hg2+, these two ssDNAs that modified respectively on the surface of the sensor and the AuNPs will create a double helix T-Hg-T structure between the two DNA oligonucleotides and result in the surface refractive index perturbation amplified by the AuNPs. To overcome the low reusability of the AuNPs based DNA biosensor, by using iodide ions that can form more stable compounds with mercury ions over the T-Hg2+-T structure, a regenerable DNA biosensor that can repeatedly detect mercury ions is developed. The experimental results demonstrate that this sensor shows an excellent ultra-low-concentration and selectivity detection capability for Hg2+ with the limit of detection (LOD) of 3.073 × 10−12 M (3.073 pM) as well as a large dynamic range of 8 order of magnitude from 1.0 × 10−11 M to 1.0 × 10−3 M simultaneously. Thus, the experimental results in various actual sample from ultrapure/tap water to even clinical human serum, also reveal that it has potential application for Hg2+ detection in environmental samples and in clinic biological samples.

Fiber-optic (FO) surface plasmon resonance (SPR) sensors can be used as label-free and highly sensitive tools for biosensing. They have been widely applied in fields of environmental monitoring, food safety, and clinical diagnosis. In this article, the development and advancement of FO-SPR sensor were reviewed. And the principle and performance of multiple SPR techniques based on optical fiber for sensing purposes were briefly summarized. Different prototypes of FO-SPR biosensors were meticulously outlined, followed by detailed discussion on novel structures and techniques. Finally, we presented an overview of most representative progresses in biochemical sensing applications using FO-SPR sensors and their future development.

In order to simultaneously detect high-frequency dynamic parameters and low-frequency quasi-static parameters through spectrum acquisition, a novel frequency-scanned parallel phase-shifting interferometry is proposed in this work. A Michelson interferometer (MI) composed of a 3 × 3 coupler is used for high-frequency vibration measurement. Different from conventional 3 × 3 fiber coupler based demodulation methods, a frequency swept laser source with flat intensity output is used. The time-varying vibrations will be encoded on the phase shifted spectra measured at two return ports of the coupler. Using a modified phase shifting algorithm, the optical path difference (OPD) changes along optical frequency can be retrieved, thereby significantly improving the sampling rate of the dynamic MI. Thanks to the full-spectrum scanning, the asymmetric parameters of non-ideal 3 × 3 couplers can be directly measured. Moreover, it provides the possibility of spectral demodulation of multiple quasi-static parameters. Another sensing channel containing multiple fiber Bragg grating (FBG) sensors is used to achieve quasi-distributed temperature measurement. Experimental results demonstrate its effectiveness in dynamic/static multi-parameter measurement.

A sandwich type titled fiber Bragg grating (TFBG) plasmonic sensor based on self-assembled p-mercaptophenylboronic acid (PMBA) monolayer and Au nanoparticles (AuNPs), has been demonstrated and successfully applied for sensitive and stable low-concentration glucose detection. The sensor was immobilized with PMBA monolayer acting as the highly sensitive and stable glucose recognition molecule instead of a traditional unstable enzyme. In the experiments, the high sensitivity for glucose detection is achieved, establishing a competitive limit of detection (LOD) of 295 pM and large dynamic measurement range from 1 nM to 10 mM simultaneously. Moreover, due to the unique two-set diol configurations of glucose, the combination of TFBG-SPR with AuNPs and PMBA exhibit a good selectivity over fructose and galactose, which both possess only one set of diol configurations. Non-invasive saliva glucose detection, as a better alternative to blood, has emerged and attracted many researchers’ attention. Therefore, the practicality of this method was successfully validated by detecting glucose in a simulated human saliva sample. We believe that this method represents an appealing solution for flexible, temperature-insensitive, high-sensitivity, and high-stability detection of ultra-low concentration glucose in modern non-invasive point-of-care testing as well as tumor micro-environment (TME) related cancer research.

When the cavity changes during spectrum acquisition process, Doppler phenomena will occur and cause conventional scanning white-light interferometry (WLI) to fail. To absolutely demodulate the cavity length of the dynamic low-finesse Fabry–Perot sensor, a novel laser frequency modulated phase-shifting WLI (PS-WLI) is proposed. Two phase-shifted spectra can be obtained by introducing a fixed phase-shift after each scanning frequency. The phase results containing modulations of frequency scanning and dynamic signals are retrieved based on quadrature demodulation. Although the full-spectrum acquisition frequency of the proposed PS-WLI is only 50 Hz, 0.5∼20 kHz vibration signals can be demodulated. It combines the advantages of frequency-switched two-step phase shifting interferometry (PSI) and scanning WLI to achieve absolute measurement with high sampling rate. Numerical simulations and experiments verify its effectiveness.

Optical fiber hot-wire anemometer is an emerging technique for wind speed measurement. In many practical applications, both the magnitude and the direction of the flow need to be obtained. However, most of previously reported fiber optic anemometers show omnidirectional response, rendering difficulty in recognizing the flow direction. Here, we propose a simple and effective fiber-optic flow sensor with directional response based on an asymmetric coating of single-wall carbon nanotubes (SWCNTs) on the surface of tilted fiber Bragg grating (TFBG), paving the way for the vector analysis of wind flow field. FLUENT software was employed to analyze the wind speed field, temperature distribution field, and vortex street. The temperature field shows asymmetrical distribution directly related to the wind directions, causing directional response of the sensor to the wind flow. In the experiments, with optimized 12˚ TFBG with 1.3 μm thick asymmetric SWCNTs coating, three wind directions at different angle (0˚, 180˚, 270˚) were clearly distinguished. Moreover, high sensitivity and efficiency were also achieved by investigating and optimizing the system parameters like pumping power, coating thickness. In addition to directional response, the proposed sensor exhibits many advantages such as simple structure, low power consumption, small size, and high sensitivity, which has good potential application for infield static wind field and slowly varying wind (SVW) measurement.

Herein, we report the simultaneously application of surface plasmon resonance (SPR) spectroscopy and electrochemistry (EC) technology for the real-time quantitative investigation of heavy metal ions, with high selectivity and sensitivity. A surface of optical fiber coated over with nanometric gold film and then modified with a dithiol self-assembled monolayer of 1,6-hexanedithiol (HDT) was developed as the dual mode electrochemical-surface plasmon resonance (EC-SPR) optical fiber sensor. The limit of detection of the proposed sensor exposed in Hg2+ ions solution without and with the multiple cyclic voltammetry (CV) scans to activate the HDT monolayer can be improved from 0.47 μM to 0.22 μM. More importantly, the CV scans can activate the redox reaction of Hg2+ ions, and then easily strip the Hg2+ ions from the HDT monolayer to restore the active sites, and endow the designed sensor the characteristics of repeated use. Under simultaneous SPR monitoring, the differential pulse voltammetry (DPV) currents of HDT-functionalized optical fiber can also act as a microelectrode to develop electrochemical sensor platform for monitoring Cu2+, with a limit of detection of 94 nM and a dynamic range up to 90 μM. As a comparison, the EC-SPR sensor still has good analysis performance for both Hg2+ and Cu2+ ions in presence of Ni2+, Fe2+, Co2+, Pb2+, K+, among others. We therefore demonstrated that the proposed fiber-based EC-SPR sensor has the advantages of real-time, miniaturized, and cost-effective sensing, paving the way for environmental monitoring applications for on site inspection.

In order to screen novel high energetic density compounds with high power and specific impulse, eight compounds containing an aza-cage or fused ring structure were designed. The B3PW91/6–31G(d,p) theoretical method was used to optimize their structures. Their power, specific impulse, impact sensitivity and the other detonation performance were predicted, and compared with that of HMX and CL-20. The results showed that the explosive powers and the specific impulses of all eight compounds were over 150 and 2.60 N s g−1, respectively, and higher than that of HMX and CL-20. Especially, the compd-1 and compd-4 compounds have excellent comprehensive performance.

The characteristics of how graphite particles adhere to the walls of high-temperature gas-cooled reactors are very important for analyzing reactor source terms. In the present study, atomic force microscopy (AFM) is used to measure the particle adhesion force and the wall morphology, then Lennard-Jones potential theory and the finite element method (FEM) are coupled to calculate the adhesion force between different particles and rough walls. The obvious deviations between the AFM measurements and the theoretical models are due to the contact hypothesis of a sphere with a smooth flat plane in the latter. The FEM results reveal the formation of maximum adhesion at the pull-off point of the particle and the corresponding stress distribution. For aspherical particles, the local curvature of the particle contact interface is the main factor affecting the adhesion force. In addition, for rough walls, different contact regimes correspond to different adhesion trends. When discrete wall roughness with hemispheres and truncated cones is used, the FEM predictions are closer to the AFM measurements, indicating that roughness dominates the adhesion weakening.

The isolation and detection of rare circulating tumor cells (CTCs) from patient peripheral blood can help early diagnosis of cancer and evaluation of therapeutic outcomes. At present, most of the available strategies for enriching CTCs face serious problems with purity due to the nonspecific interactions between the capture medium and leukocytes. Inspired by the immune evasion ability of homologous red blood cells (RBCs), we modified the tumor-targeting molecule folic acid (FA) on the surface of RBCs by hydrophobic interactions. Under the treatment of polybrene, the charges on the surface of RBCs are neutralized, which reduces the mutual repulsion force. Furthermore, RBCs treated with polyethylene also have excellent deformability, thereby enabling engineered RBCs to form a dense bionic layer on the adhesive glass slide, which can greatly inhibit the nonspecific adhesion of leukocytes. The bionic layer can achieve high-purity enrichment of tumor cells in phosphate-buffered saline (PBS), and we can achieve high-activity release in plasma. The cell count showed over 80% capture efficiency and over 70% release rate, and the purity of CTCs obtained in the artificial blood sample after release was higher than 90%. The RBC bionic surface coating is notably cost-effective and highly applicable for CTC isolation in clinic practice, and thus provides new prospects for designing cell-material interfaces for advanced cell-based biomedical studies in the future.

The strength of backfill plays an important role in the stability and safe mining of goaf. Considering the influence of underground acid environment, the physical characteristics and corrosion mechanism of cemented tailings backfill (CTB) are studied. Based on the accelerated test method of the acid environment, the mass change fraction, longitudinal wave velocity, porosity, volume and appearance change in sulfuric acid solution of the CTB in different corrosion periods were measured and analyzed. In addition, the concentration of H+ in solution was monitored, and the surface material of the corroded backfill was analyzed by X-ray diffraction and scanning electron microscopy. The results show that acidic corrosion increases the porosity, longitudinal wave velocity, and volume of the CTB after soaked 60 days. Acidic corrosion also increases the quality of the CTB in the early stage of corrosion. The quality of the CTB deceased with day of corrosion in long term. Corrosion causes the surface of the CTB to bulge and fall off. The corrosion mechanism of the CTB was found to be generated by two kinds of destructive factors: the dissolution reaction of H+ ion and S042− ion resulted in the swelling material.

In extreme heat transfer environments, functionally graded materials (FGMs) have aroused great concern due to the excellent thermal shock resistance. With the development of micro-scale devices, the size-dependent effect has become an important issue. However, the classical continuum mechanical model fails on the micro-scale due to the influence of the size-dependent effect. Meanwhile, for thermoelastic behaviors limited to small-scale problems, Fourier’s heat conduction law cannot explain the thermal wave effect. In order to capture the size-dependent effect and the thermal wave effect, the nonlocal generalized thermoelastic theory for the formulation of an FGM microbeam is adopted in the present work. For numerical validation, the transient responses for a simply supported FGM microbeam heated by the ramp-type heating are considered. The governing equations are formulated and solved by employing the Laplace transform techniques. In the numerical results, the effects of the ramp-heating time parameter, the nonlocal parameter, and the power-law index on the considered physical quantities are presented and discussed in detail.

Oxygen vacancy in oxide ferroelectrics can be strongly coupled to the polar order via local strain and electric fields, thus holding the capability of producing and stabilizing exotic polarization patterns. However, despite intense theoretical studies, an explicit microscopic picture to correlate the polarization pattern and the distribution of oxygen vacancies remains absent in experiments. Here we show that in a high-quality, uniaxial ferroelectric system, i.e., compressively strained BaTiO3 ultrathin films (below 10 nm), nanoscale polarization structures can be created by intentionally introducing oxygen vacancies in the film while maintaining structure integrity (namely no extended lattice defects). Using scanning transmission electron microscopy, we reveal that the nanodomain is composed of swirling electric dipoles in the vicinity of clustered oxygen vacancies. This finding opens a new path toward the creation and understanding of the long-sought topological polar objects such as vortices and skyrmions.

Shock waves can significantly affect the film cooling for supersonic flow and shock waves may have different influence when impinging in different regions. The present study numerically compared the results of shock wave impinging in three different regions and analyzed the effect of impinging region. The shock wave generators were located at x/s = 5, 25, 45 with 4°, 7° and 10° shock wave incidence. The mainstream Mach number was 3.2 and the coolant Mach number was 1.2 or 1.5. The numerical results illustrated that the shock wave impinged in the further upstream region led to a larger high-pressure region and a larger vortex in the boundary layer. Moreover, placing the shock wave generator upstream resulted in the lower mass fraction of coolant in the downstream region. The velocity in the upstream part of the cooling layer was lower than the midstream and downstream part, which resulted in the less ability to resist the shock wave impingement. Therefore, the upstream impingement deteriorated the cooling performance to a greater extent. The study also manifested that the stronger shock wave had a larger effect on supersonic film cooling. Increasing the coolant inlet Mach number can increase the blowing ratio and reduce the mixing, which was of benefit to improve cooling effect.

A series of copolymers of thiazoloisoindigo (TzII) with different chalcogenophene trimers were synthesized to systematically investigate the chalcogen effect on their charge transport properties. When only the middle thiophene ring of terthiphene (T-T-T) is replaced by heavier chalcogenophenes, a preference (expressed by the ratio of μe/μh) towards electron transport was observed descending from T-T-T to T-Se-T then to T-Te-T (Se and Te stand for selenophene and tellurophene, respectively). On the other hand, with the increased number of heavier chalcogenophenes, a preference toward hole transport was observed descending from Se-T-Se to Se-Se-Se then to Se-Te-Se. This phenomenon is well-explained by the balance between the aromatic resonance energy of the chalcogenophenes and the electronegativity of the chalcogens. Specifically, P(TzII-T-Se-T) displayed relatively balanced ambipolar property (μhmax and μemax of 3.77 and 1.59 cm2·V−1·s−1 with a μe/μh of 0.42), while P(Tzll-Se-Te-Se) exhibited the best preference to hole transfer with a μe/μh of 0.09. P(Tzll-T-Te-T) exhibited the best preference to electron transfer with a μe/μh, of 16 and the μemax of 0.64 cm2·V−1·s−1 which is the highest electron mobility among the known conjugated polymers containing tellurophenes.

Ceramics' micromorphology plays a pivotal role on their dielectric and tunable properties. Thus, many methods are used to modify the micromorphology of ceramics to improve the dielectric and tunable properties. However, the mechanisms about the influence of raw materials' particle diameters on the dielectric and tunable properties have seldom been investigated. In this study, the (Ba0.91Ca0.09)(Zr0.2Ti0.8)O3 ceramics were synthesized using the nanoscale BaTiO3 (BT) powders as Ti sources to study the effect of the BT particle diameters on the structure, micromorphology, dielectric properties, and tunable performance. When the BT particle diameters decreased from 500 nm (BT05) to 400 nm (BT04), the grain size sharply increased and then slightly decreased as the particle diameter further decreased to 100 nm (BT01) due to the influence of oxygen vacancies. The generated oxygen vacancies, which were verified by the XPS results, introduced compressive stress, resulting in the reduction of the cell volume and Curie temperature. A large e value (~17,500) was achieved at room temperature when the particle diameters were 100 nm. The large e contributed to the high tunability (~70%), which was greater than that of the BT05 ceramic (~49%). Due to the high tunability, the BT01 ceramic's figure of merit was more than twice as that of the BT05 ceramic. This study demonstrated that the dielectric and tunable properties of (Ba0.91Ca0.09)(Zr0.2Ti0.8)O3 ceramics can also be controlled by the raw materials' particle diameters.

The silicon-controlled rectifier (SCR) has been reported to protect CMOS integrated circuits (ICs), due to high ESD robustness within a small silicon area. However, the holding voltage ( ${V}_{h}{)}$ of the SCR device was too low to suffer the latch-up issue. Thus, the ${V}_{h}$ value of the SCR device must be improved to be greater than the circuit operating voltage for safe applications. In this work, the Schottky-embedded modified lateral SCR (SMLSCR) with high holding voltage for ESD protection was proposed and verified in a 0.18- $\boldsymbol \mu \text{m}$ 1.8-V/3.3-V CMOS process. By using the Schottky barrier junction, the ${V}_{h}$ value of the SCR device can be improved by the reverse-bias Schottky barrier diode (SBD) that is embedded into the SCR device structure. Among those experimental results on the SMLSCR devices with split layout parameters in the silicon test chip, the SMLSCR device without $\text{P}^{+}$ guard ring has the best second breakdown current ( ${I}_{{t{2}}}{)}$ of 3.1 A and a high ${V}_{h}$ value of 9.7 V.

Spin-orbit torques (SOTs) from transition metal dichalcogenides systems (TMDs) in conjunction with ferromagnetic materials are recently attractive in spintronics for their versatile features. However, most of the previously studied crystalline TMDs are prepared by mechanical exfoliation, which limits their potentials for industrial applications. Here we show that amorphous WTe2 heterostructures deposited by magnetron sputtering possess a sizable damping-like SOT efficiency {\xi}_DL^WTe2 ~ 0.20 and low damping constant {\alpha} = 0.009/pm0.001. Only an extremely low critical switching current density J_c ~ 7.05\times10^9 A/m^2 is required to achieve SOT-driven magnetization switching. The SOT efficiency is further proved to depend on the W and Te relative compositions in the co-sputtered W_100-xTe_x samples, from which a sign change of {\xi}_DL^WTe2 is observed. Besides, the electronic transport in amorphous WTe2 is found to be semiconducting and is governed by a hopping mechanism. With the above advantages and rich tunability, amorphous and semiconducting WTe2 serves as a unique SOT source for future spintronics applications.

The development of efficient and stable catalysts for the oxygen reduction reaction (ORR) at low cost is crucial for realizing the large-scale application of metal-air batteries. Herein, we report an efficient ORR catalyst of bimetallic copper and cobalt fluoride heterojunctions, which are uniformly dispersed in nitrogen-fluorine-oxygen triply doped porous carbon nanofibers (PCNFs) that contain hierarchical macro-meso-micro pores. The composite catalyst materials are fabricated with a facile and green method of electrospinning with water as the solvent. By using poly(tetrafluoroethylene) as the pore inducer to anchor electropositive copper and cobalt salts in the electrospun hybrid nanofibers, bimetallic fluoride heterojunctions can be directly formed in PCNFs after calcination. The hierachical porous structures provide an effective way to transport matter, while the bimetallic fluorides expose abundant electroactive sites, both of which result in stable ORR activities with a high half-wave potential of 0.84 V. The study proposes a feasible strategy for the fabrication of nonprecious catalysts.

In this study, we investigated the dielectric tunable performance of (BaxCa1-x)(Zr0.2Ti0.8)O3 ceramics (x = 0.95, 0.91 and 0.87) using Landau-Devonshire theory. According to the dielectric constant-temperature (e-T) curves, the Curie temperature is found to be 15.0 °C, 5.0 °C and 2.5 °C for x = 0.95, 0.91 and 0.87, respectively. It indicates that all the prepared ceramics possess a low loss tangent ( tan δ ) at room temperature, which is in favor of achieving a high figure of merit (FOM) and commutation quality factor (CQF). For a better understanding of the dielectric tunable performance, the Landau-Devonshire theory is used. The associated Landau coefficients have been derived based on the e-T and tunability-electric field (k-E) curves. According to the calculated free energy-electric field and polarization-electric field curves, the prepared ceramics are in the paraelectric phase at room temperature, which is in accord with the e-T curves. Meanwhile, the calculated results indicate that a high dielectric constant is obtained in the (Ba0.91Ca0.09)(Zr0.2Ti0.8)O3 ceramic at room temperature. Owing to the high e and low tan δ , a high value of FOM and CQF are obtained in the (Ba0.91Ca0.09)(Zr0.2Ti0.8)O3 ceramic at ~740 kV/m. The high value of FOM (197.7) and CQF (43130) indicates that the (Ba0.91Ca0.09)(Zr0.2Ti0.8)O3 ceramic has a potential application in tunable devices.

In this article we demonstrated a novel interference behavior excited by visible light in the capillary waveguide (CWG). We investigated the sensing principle of CWG with filling liquid and optical characteristics of interference systematically. This CWG-based sensing element is theoretically verified to possess continuously tunable thermal sensitivity by changing the thermo-optic coefficient of the filling liquid. As expected, experimental results show that the proposed sensor possesses sharp interference fringes and the tunable sensitivity of temperature. Unlike most optical fiber interferometers, the optical path difference of our sensing element is generated in the wall of CWG instead of air cavity. Besides, interference occurs in the visible light band, which greatly improves dynamic range and reduces the cost of system setup. The novel optical behavior we investigated offers a way to the utility of the waveguide as an optical interferometer.

A new family of isostructural 3d-4f polymetallic complexes, formulated as [Cu(6)Ln(5)(mu(3)-OH)(9) (C4H8O2N)(6)(C5H4ON)(6)(H2O)(9)].(ClO4)(6).(H2O)(22) (Ln = Pr, 1; Nd, 2; Sm, 3; Eu, 4; Gd, 5), was successfully isolated through the simple hydrolysis reaction of 2-aminoisobutyric acid, 2-hydroxypyridine, Cu(CH3COO)(2).H2O, and Ln(ClO4)(3).6H(2)O. Notably, the [Cu(6)Ln(5)] clusters with high molecular symmetry of D3h are rare examples of 2-aminoisobutyric acid-based 3d-4f clusters. The successful theoretical modeling of 5 yielded that the Gd-Gd exchange is of order 0.2 K, whereas the Gd-Cu exchange is an order of magnitude larger. Magnetization data collected for complex 5 yield a magnetic entropy change (-Delta S-m) of 19.6 J kg(-1) K-1 at 3 K and 7 T, which may be attributed to the weak magnetic interactions between the component metal ions. (C) 2020 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.

Relaxor ferroelectrics are attracting an increasing interest in the application of pulse power systems due to their excellent energy storage performance. In this paper, the (1-x)(Ba0·85Ca0.15)(Zr0·1Ti0.9)O3-xBi(Mg0·5Ti0.5)O3 ((1-x)BCZT-xBMT, x ≤ 0.2) relaxor ceramics are prepared by the solid state method. The influence of BMT on the microstructure, dielectric and energy storage properties of the prepared ceramics is investigated. The XRD results show that the peak intensity of impurities (Bi2O3, TiO2 and Ba2Bi4Ti5O18) is gradually stronger than that of BCZT phase with x increasing. Meanwhile, the grain size of (1-x)BCZT-xBMT ceramics gradually increases on account of the appearance of impurities Bi2O3. Influenced by the impurities and BMT, the dielectric constant of prepared ceramics gradually decreases with x increasing. A large Wrec value of 0.65 J/cm3 with an ultrahigh η value of 97.89% is achieved at x = 0.15 due to the high breakdown strength and slim P-E hysteresis loop. Meanwhile, the η is insensitive to the electric field. The ultrahigh η leads to lesser energy loss during the charge and discharge process. It makes the 0.85BCZT-0.15BMT ceramic more attractive in the application of pulse power systems.

Drift of Quadrature operating point (Q-point) due to variations in ambient temperature restricts the demodulation accuracy of fiber-optic extrinsic Fabry-Perot interferometer (EFPI) sensors. To overcome this challenge, in this paper, we propose and demonstrate a self-stabilizing Q-point system based on Vernier-tuned distributed Bragg reflectors (VT-DBR) laser, the laser wavelength is locked to a point with the maximum slope on the interference spectrum of fiber-optic EFPI sensor. Taking advantage of large-tuning range (40nm) and fast wavelength switching capability (

In this paper, we propose and demonstrate a high-performance mercury ion sensor with sub-nM detection limit, high selectivity, and strong practicability based on the small molecule of the 4-mercaptopyridine (4-MPY) modified tilted fiber Bragg grating surface plasmon resonance (TFBG-SPR) sensing platform. The TFBG-SPR sensor has a rich mode field distribution and a narrow bandwidth, which can detect the microscopic physical and chemical reactions on the sensor surface with high sensitivity without being disturbed by the external temperature. For the environmental compatibility and highly efficient capture of the toxic mercury ion, 4-MPY is modified on the sensor surface forming a stable (4-MPY)-Hg-(4-MPY) structure due to the specific combination between the nitrogen of the pyridine moiety and the Hg2+ via multidentate N-bonding. Moreover, gold nanoparticles (AuNPs) are connected to the sensor surface through the (4-MPY)-Hg-(4-MPY) structure, which could play an important role for signal amplification. Under the optimized conditions, the limit of detection of the sensor for mercury ions detection in the solution is as low as 1.643×10−10 M (0.1643nM), and the detection range is 1×10−9 M − 1×10−5 M. At the same time, the mercury ion spiked detection with tap water shows that the sensor has the good selectivity and reliability in actual water samples. We develop a valuable sensing technology for on-time environmental Hg2+ detection and in-vivo point of care testing in clinic applications.

Strong electromagnetic coupling among plasmonic nanostructures paves a new route toward efficient manipulation of photons. Particularly, plasmon-waveguide systems exhibit remarkable optical properties by simply tailoring the interaction among elementary elements. In this paper, we propose and demonstrate a freestanding bilayer plasmonic-waveguide structure exhibiting an extremely narrow transmission peak with efficiency up to 92%, the linewidth of only 0.14 nm and an excellent out of band rejection. The unexpected optical behavior considering metal loss is consistent with that of electromagnetic induced transparency, arising from the destructive interference of super-radiative nanowire dipolar mode and transversal magnetic waveguide mode. Furthermore, for slow light application, the designed plasmonic-waveguide structure has a high group index of approximately 1.2 × 105 at the maximum of the transmission band. In sensing application, its lowest sensing figure of merit is achieved up to 8500 due to the ultra-narrow linewidth of the transmission band. This work provides a valuable photonics design for developing high performance nano-photonic devices.

The electrochemical reduction of CO2 to an ethanol product is regarded as a highly promising route for CO2 utilization. However, the poor selectivity is still a critical challenge for increasing the yield of the specific ethanol. As a CO2 reduction catalyst, the hierarchically nanoporous copper integrated with vanadium oxide can achieve a 30.1% faradaic efficiency for CO2-to-ethanol production and an ethanol partial current density of −16 mA cm−2 at −0.62 V vs. RHE, corresponding to a 4-fold increase in activity compared to bare nanoporous Cu. It even delivers an ethanol partial current density that exceeds −39 mA cm−2 at −0.8 V vs. RHE in a flow-cell reactor. The hierarchically nanoporous Cu skeleton not only facilitates both electron and electrolyte transport but also provides a large specific surface area for high active site density. Density functional theory reveals that the vanadium oxide decorated Cu surface can facilitate water dissociation and optimize the hydrogen adsorption energy on Cu, lowering the energy barrier for the protonation of carbon dioxide and C–C coupling. Meanwhile, it can increase hydrogen proton coverage on the catalyst surface and inhibit dehydration, which are beneficial for breaking the CC bond of the *HCCOH intermediate, thus enhancing the faradaic efficiency of ethanol significantly. The highly efficient conversion of CO2 to ethanol demonstrates that the hybrid electrocatalyst is considered as a promising candidate for practical electrocatalytic CO2RR applications.

By using a photosensitizer [Ru(bpy)3]2+ as a template, a rare example of a three-dimensional Sn–Se type anionic framework, formulated as {Ru(bpy)3@[Sn4Se9]}n1 (bpy = 2,2′-bipyridine), has been synthesized, and shows evident photocurrent response in the visible light region and related semiconducting behavior.

Interferometric fiber-optic microphones (FOMs) with outstanding sensitivity are ideal method to detect weak acoustic signals. In this work, we demonstrated an ultrasensitive fiber-optic Michelson microphone with dual enhancement by using a diaphragm-free acoustic transducer and a high-resolution optical path difference (OPD) demodulation device. A cylindrical polyvinyl chloride (PVC) tube wrapped around by the optical fiber was employed as a transducer to enhance the responsivity to weak acoustic wave. A high-resolution spectrum demodulation-based white-light interferometer (WLI) was utilized to measure the variations of OPD. In theory, the FOM owns features to overcome defects of the conventional diaphragm-based or intensity demodulation method-based FOMs, such as quadrated point ( ${Q}$ -point) drifting and being sensitive to environmental interference. Experimental results showed that this FOM had an ultrahigh sensitivity of ~6800 nm/Pa at the resonance frequency of 1455 Hz. The sensitivity and the noise-limited minimum detectable sound pressure level (MDSPL) at 1000 Hz were calculated to be 315.3 nm/Pa and − 20.4 dB/Hz1/2 ( $1.9~\mu $ Pa/Hz1/2), respectively.