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Despite the continuously increased requirement on automated synthesis of medicines for distributed manufacturing and personal care, it remains a challenge to realize automated synthesis which requires solid-liquid phase reactions. In this work, we demonstrated an automated solid-liquid synthesis for gadopentetate dimeglumine, the most widely used magnetic resonance imaging (MRI) contrast agent. The high-efficiency reaction was performed in a 3D microfluidic chip which was fabricated by femtosecond laser micromachining. The structure of the chip realized 3D shear flow which was essential for highly efficient mixing and movement of the solid-liquid mixtures. Ultraviolet visible (UV–vis) spectrometer was employed for in-line analysis to help automation of this system. Comparing with the round-bottom flask system, this synthetic system showed significantly higher reaction rate, indicating the advantage of the 3D microfluidic technology in micro chemical engineering.

The application of frequency diverse array and multiple-input multiple-output (FDA-MIMO) radar to achieve the joint estimation of target's range and angle is receiving more and more attention. However, its performance is generally affected by the periodicity and time-varying of its beam pattern. Therefore, this paper implements a joint estimation algorithm of target's range and angle based on a new waveform synthesis model of time modulation and range compensation FDA-MIMO (TMRC-FDA-MIMO) radar. At the same time, the multiple signal classification (MUSIC) algorithm is mainly used in FDA-MIMO radar. The huge amount of calculation also brings difficulties to the implementation of the system. Therefore, this paper proposes an improved estimating signal parameters via rotation invariance technique algorithm to solve the problem of large amount of calculation on the basis of ensuring system performance. In addition, the closed form expressions of the Cramer–Rao lower bound and root-mean-squared error of range and angle estimation are derived. Theoretical analysis and simulation verify the effectiveness of the proposed method and demonstrate the excellent performance of the proposed radar system and algorithm.

In today's automotive ICs, online safety checking is often required in order to achieve a high Automotive Safety Integrity Level (ASIL). For a Delay-Locked Loop (DLL), the most important safety (or health) indicator is the “phase error between the input clock signal and the output clock signal”. In this paper, we present a phase error monitoring scheme for DLLs, using circuits made of only standard cells. The proposed scheme can monitor the phase error continuously to record its worst-case values during a designated monitoring session. As a result, hazardous phase error glitches can be exposed and an alarm can be raised. We have implemented this monitoring scheme for a Delay Lock Loop in a 90 nm CMOS process and post-layout simulation is conducted to verify its effectiveness. Experimental results show that it can help expose hazards induced by dynamic power glitches that occurs within 1ns.

A hybrid electrocatalyst composed of NiCoP and MoxC has been prepared via the two-step calcination method. Microscopic analysis demonstrates that the heterojunctions formed by the NiCoP and MoxC are disordered and stacked irregularly. The NiCoP/MoxC heterojunctions are produced during the second calcination treatment. The synergistic effects promote water adsorption and dissociation, and H2 desorption. More active sites are provided by the irregular structure, the NiCoP/MoxC-X catalyst are imparted excellent electrocatalytic activity toward hydrogen evolution reaction (HER) activity. To sustain a current density of 10.0 mA/cm2, the overpotentials of NiCoP/MoxC-15 are 79.0 and 116.0 mV while the Tafel slopes are 52.3 and 57.4 mV/dec for the electrocatalyst operated in 1.0 M KOH and 0.50 M H2SO4, respectively. When operating in alkaline medium for 10.0 h at an overpotential of 123.0 mV, the retaining catalytic activity of this material reaches 93.0%.

We investigate the effects of gas-liquid ratio (GLR) on the spray and atomization process of a liquid-centered swirl coaxial injector using the coupled level-set and volume of fluid (CLSVOF) method. The flow field, gas-liquid interaction, and breakup of liquid film during adaptive mesh refinement are evaluated and analyzed. The results show that, with the increase of GLR, the atomization process becomes dominated successively by the instability of the liquid film, strong gas-liquid interaction and spray self-pulsation. Moreover, more droplets are found near the center of the spray cone while the spray angle decreases. The inclined surface waves on the liquid film may be formed owing to Rayleigh-Taylor instability. When GLR is relatively large, holes are produced and break up on the liquid film due to the high velocity of the gas. Then, the gas-liquid interaction pushes small droplets towards the center of the spray cone, while large droplets and ligaments distribute on the periphery of the spray. With even larger GLRs, self-pulsation occurs, which is found to determine the flow structures inside the spray cone and to generate, shed and dissipate vortices periodically. Furthermore, when self-pulsation occurs, the near-field pressure and mass flow rate fluctuations increase rapidly.

It has been widely accepted that the viscosity of alloy melts increases monotonically with temperature decreasing after exceeding the liquidus temperature. However, a distinct viscosity-drop has been observed in several alloy melts in our previous works. To further understand this dynamic anomaly, we investigated the viscosity of CuZrAl and CuZrTiNi melts by gradually changing the compositions of alloy systems. The results suggest that when the amounts of doping elements (Al, Ti, Ni) become large enough, this abnormal viscosity-drop disappears. For CuZr binary alloys, the anomaly exists when the composition of Zr ranges between 27.3–66.7%, which nearly corresponds to the available content of Zr in CuZr bulk metallic glasses. By conducting molecular dynamics simulation, the mechanism that four icosahedron-like clusters with high fragility evolves with temperature in Cu62Zr38 melts has been recognized. In contrast to general aggregation or growth of clusters during cooling process, an unexpected tendency that more segregations are formed among these clusters and the clusters become further dispersed in liquids has been discovered around 1400 K; meanwhile, the viscosity-drop in our experiments begins simultaneously at this temperature. Below 1300 K, these icosahedron-like clusters aggregate abruptly again. Experimental results from differential scanning calorimeter (DSC) and high-resolution transmission electron microscope (HRTEM) further approve the influence of these fragile icosahedron-like clusters on crystallization processes. This finding uncovers the same structural origin that underlies both the formation of bulk metallic glasses and the dynamic anomaly in melts, and demonstrates the dominant role of fragile icosahedron-like clusters in the feature of liquid dynamics.

NiZrAl layered double hydroxides (LDH) precursors were synthesized by co-precipitation and homogeneous precipitation processes. The introduction of hydrothermal treatment into crystallization showed its significant influences on structure of LDH as well as mixed-metal oxides after thermal decomposition. The characterization results showed that the catalysts prepared by hydrothermal synthesis involved bigger pore diameter of ca. 13.5 nm and wider pore size distribution of 2–60 nm, and hydrothermal treatment was helpful to enhance the reduction of NiO species weakly interacted with support and to enhance the interaction among the metal oxides. Although the Ni dispersion, the surface area as well as the ability of anti-sintering were evidently improved, the ability of coke resistance decreased by 2 times for samples prepared by co-precipitation and by nearly 10 times for the ones prepared by homogeneous precipitation due to the enlarged pores. The maximum value of conversion to gaseous products (96.5%) and minimum deposited coke (36 mgc/gcat.) were achieved on NiZrAl-u sample.

Lithium-rich layered oxides have the advantages of high specific capacity (> 250 mAh g−1) and high energy density, which make them highly competitive in the lithium-ion cathode material market. However, low efficiency, poor cycle stability, and poor rate performance severely constrained their development. In this paper, the spherical lithium-rich Li1.2Mn0.54Ni0.13Co0.13O2 compound was rapidly synthesized by microwave hydrothermal method, and the microwave hydrothermal time was optimized. The samples were characterized and analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy (Raman), and X-ray photoelectron spectroscopy (XPS). The prepared lithium-rich compound is porous spherical secondary particles, of which the size distributed between 2.5 and 3.5 μm, which makes materials have larger specific surface area and active potential and promotes the improvement of electrochemical kinetics. The results of 100 charge-discharge cycles show that the microwave hydrothermal 40-min cathode has good stability, and the capacity retention rate can reach 91.4%. Furthermore, it can still provide a discharge capacity of 160.5 mAh g−1 at a current density of 5 C.

A series of mesoporous CoxM3-xAlOy (M Ni, Mn) catalysts have been obtained by calcination of layered double hydroxide (LDH) precursors prepared by the microwave method, the catalysts exhibited high activity for methane catalytic combustion. By changing the preparation method and type of metal salt introduced (Ni and Mn), it is effective for controlling the structure properties and reducibility of catalyst as well as the catalytic performance for the methane catalytic combustion. The Co2Ni1AlOy catalyst exhibited higher catalytic performance and the temperature required to achieve a methane conversion of 90% (T90) was about 473 °C, this temperature was 40 °C lower than that on the NiO-IWI/Co3AlOy sample. The enhanced catalytic activity was correlated with higher surface area, better redox property, higher ratio of surface Co3+/Co2+ species and surface absorbed oxygen and lattice oxygen (Oads/Olatt) derived from the synergistic effect over Co2Ni1AlOy catalyst. Therefore, the microwave method provided an effective path to develop the efficient combustion catalyst for higher performance.

Interfacial electron transfer within the electrode is crucial for various electrocatalytic reactions. Herein, we demonstrated that in-situ grown Cu2O on Cu foam as a scaffold to load active ingredients could lower the interfacial contact resistance and promote the electron transfer in oxygen evolution reaction. Meanwhile, the Cu2O/Cu (CCF) facilitates to load active components due to higher surface area resulting from its irregular scattered structure. As a demonstration, Ni–Fe doubles layered hydroxide (NiFe-LDH) coated carbon nanotube spheroidal particles (CNS@NiFe) was anchored by a drop-casting route to assemble CNS@NiFe/CCF hybrid electrodes with the CCF as scaffolds. The CNS@NiFe/CCF electrode afforded an ultralow overpotential of 248 mV at 10 mA cm−2 and a small Tafel slope of 32.9 mV dec−1 with an excellent stability. Schematic illustration of CNS@NiFe/CCF architecture.

A series of CuCo2O4 composite spinels with an interconnected meso-macroporous nanosheet morphology were synthesized using the hydrothermal method and subsequent calcination treatment to activate peroxymonosulfate (PMS) for benzophenone-4 (BP-4) degradation. As-prepared CuCo2O4 composite spinels, especially CuCo-H3 prepared by adding cetyltrimethylammonium bromide, showed superior reactivity for PMS activation. In a typical reaction, BP-4 (10.0 mg/L) was almost completely degraded in 15 min by the activation of PMS (200.0 mg/L) using CuCo-H3 (100.0 mg/L), with only 9.2 μg/L cobalt leaching detected. Even after being used six times, the performance was not influenced by the lower leaching of ions and surface-absorbed intermediates. The possible interface mechanism of PMS activation by CuCo-H3 was proposed, wherein a unique interconnected meso-macroporous nanosheet structure, strong interactions between copper and cobalt, and cycling of Co(II)/Co(III) and Cu(I)/Cu(II) effectively facilitated PMS activation to generate SO4•- and •OH, which contributed to BP-4 degradation. Furthermore, combined with intermediates detected by liquid chromatography quadrupole time-of-flight mass spectrometry and density functional theory calculation results, the degradation pathway of BP-4 involving hydroxylation and C-C bond cleavage was proposed.

Photon capturing is an essential step for the operation of a solar cell. In this article, we develop a bifacial solar cell with characteristics of double-side photon collection, transparent appearance, mechanical flexibility, and facile processing. The whole device was fully fabricated by a spin-coating technique. A power conversion efficiency (PCE) as high as 2.46% has been achieved using the most prominent photoactive material, poly(3-hexylthiophene):(6, 6)-phenyl C61 butyric acid methyl ester (P3HT:PCBM). The bifacial solar cell can retain 92% of its original PCE after 350 cyclic bending cycles at bending radii of 7.4 mm. In addition to the mechanical instability of the device, photochemical degradation is partially involved in the device operation. We believe that our device with its promising mechanical, physical, and processing features can serve as an essential power element to be integrated with other technologies for the next-generation self-powered technology.

There is a lack of understanding of the spray characteristics of gas-centered swirl coaxial (GCSC) injectors during self-pulsation occurs. Therefore, the self-pulsation of a GCSC injector was investigated experimentally in this study. Experiments were conducted at atmospheric pressure with filtered water and dried air supplied through a propellant feed system. A back-lighting high-speed photography technique was used to capture unsteady spray features. A laser-based particle size analyzer (LPSA) was used to measure the size of the droplets in the spray. The effects of recess and gas-liquid ratio on spray self-pulsation were analyzed. It was found that the recess of the injector strongly determines the spray pattern. When spray self-pulsation occurs without recess, both the center and periphery of the spray oscillate. With an increase in the mass flow rate of the gas, the boundary between the center and the periphery of the spray becomes more noticeable. Meanwhile, small droplets in the spray center oscillate, with the periphery of the spray being characterized by a periodic “shoulder.” Under the same operating conditions but with a small recess (2 mm), the spray adheres to the injector faceplate. With a larger recess (7 mm), when spray self-pulsation occurs, the spray periodically forms “shoulder” and “neck,” similar to the behavior of self-pulsation in a liquid-centered coaxial injector. Therefore, it can be concluded that spray self-pulsation enhances atomization at the center of the spray to a certain extent. However, atomization becomes worse in the periphery with an oscillating spray.

In recent years, the primary greenhouse gas (carbon dioxide) has caused a series of severe issues, such as global warming, climate change, etc. Therefore, CCU, CCS and CCUS technologies have been employed to reduce CO₂ emissions. Through our developed "chemical vapor deposition integrated process (CVD-IP)" using carbon dioxide as the carbon source, CO₂ could be catalytically activated and converted to high-value carbon nanotubes. In this work, methane and carbon dioxide has been applied to synthesize CNTs respectively to compare the difference between conventional CH4 CVD and CO₂ CVD-IP technology using Ni-Mo bimetallic catalysts. In the conventional CH4 CVD technology, the carbon productivity and the thermal stability of CNTs could be improved by changing the Mo content of the catalyst, the better catalytic performance 4% Mo catalyst is selected as model catalyst to apply to CO₂ CVD-IP technology. Moreover, when the weak oxidant CO₂ is the only carbon source in the CVD-IP technology, the carbon yield is 22% and the carbon productivity is 1.98 g/gcat. TG curves and Raman spectroscopy display that the CNTs with better thermal stability and higher degree of graphitization are achieved. TEM confirms that the fewer wall numbers and defects of CNTs are obtained. These characterizations suggest that the high quality CNTs could be achieved by CO₂ CVD-IP technology.

A DFT investigation was performed to evaluate the structure, electronic properties of the doped graphene, and the adsorption behavior of C₂H₂ and H₂ on the graphene sheet. Two kinds of doping scenarios are considered, namely dopants into pristine graphene and vacancy graphene. It is observed that the doping energy is negative for dopant (N, P, S) into vacancy graphene at pyridinictype site, yet it is positive at graphitic-type site for pristine graphene. It could be inferred that the introducing process is exothermic reaction for defective graphene. Meanwhile, for the adsorption of C₂H₂ on the surface of defective graphene, we notice that C₂H₂ would prefer to be adsorbed at the top site of the doping atom and the adsorption energy increases with the introducing of dopants, indicating that the dopant would enhance the interaction between C₂H₂ and graphene. Regarding hydrogen molecule, the dopant has less promotion effect on the adsorption. Moreover, the graphene plays a role of electron donor while the gas molecule (C₂H₂/H₂) is the electron acceptor when it is adsorbed. For the co-adsorption, the C₂H₂ is privileged to interact with the graphene and the pre-adsorbed C₂H₂ on doped graphene would weaken the opportunity of the uptake of H₂ molecule. We anticipate that our results would provide information to design the optimized catalysts.

In this article, a novel technique is applied to achieve time-invariant spatial focusing performance for static and moving target by applying an irregular frequency modulation method to a frequency diverse array (FDA) waveform transmission system. The FDA radar can improve the anti-noise ability of the system by the means of concentrating the waveform energy on the required range or angle sector. However, the synthesized waveform has high sidelobes and is time-varying during the transmission waveform. In view of the above problems, a new waveform synthesis model of rang compensation frequency diverse array (TMRC-FDA) is established and the effect of parameter $$\varsigma$$ on the waveform synthesis is analyzed. A new accelerated particle swarm optimization algorithm is used to optimize the distribution of parameter $$\varsigma$$. The numerical simulation results show that the proposed TMRC-FDA waveform synthesis method achieves the goal of time invariance and reduces the waveform sidelobes. At the same time, it has better performance in terms of waveform focus compared to log-frequency offset FDA based on time-modulated and fixed parameters $$\varsigma$$.

The environmentally friendly technology of high-frequency ultrasonic processes with the mostly concerned frequencies of 200 kHz and 400 kHz were applied and investigated systematically for BPA degradation in both pure water and river water mediated conditions. Investigations were carried out examining the effects of crucial parameters determining the system efficiency and BPA degradation mechanisms. Results proved that BPA was efficiently degraded via the oxidation by •OH. The 400 kHz ultrasonic process demonstrated much stronger capability in generating •OH and corresponding higher efficiency in BPA degradation based on electron spin resonance analysis. Increasing solution volume could increase the radical yields, and the temperature increase rate (dT/dt) showed linear relationship with kobs. In addition, the degradation of BPA with different concentrations was for the first time found controlled by different limiting factors, in which the degradation only with higher concentrations (≥0.02 mM) conformed to the Langmuir–Hinshelwood mechanism. More acidic condition and the bulk temperature of about 40 °C favored BPA degradation. The presence of NO3−, SO42−, and Cl− demonstrated minor influence while CO32−, HCO3− and NO2− showed significant inhibition, and the effects of different anions also depended on their concentrations. The degradation rate decreased 23% when river water was used as the matrix. Furthermore, both hydroxylation of the benzene ring and attack on the connecting carbon were found to be the reaction pathways, and the latter was proposed to be more dominant.

Nickel based catalysts were prepared by incipient wetness impregnation method using CeO2 with morphologies of nanorods and nanoparticles as supports. Nickel nitrate in catalyst precursors was decomposed either by thermal calcination or glow discharge plasma treatment. The effects of plasma treatment and CeO2 morphologies on the catalytic performance of glycerol steam reforming were investigated. Characterization and catalytic results showed that Ni/rCeO2-P catalyst, supporting on CeO2 nanorods and treated by glow discharge plasma, had higher nickel dispersion, higher nickel reducibility, more acid sites as well as more amounts of surface oxygen vacancies and Ce3+. These features were beneficial for the formation of more active Ni0 sites, the stabilization of nickel particles from sintering, and hindering the coke deposition during reaction. This catalyst thus showed the best catalytic performance in glycerol steam reforming reaction, including high activity, high selectivity to hydrogen, and good stability in 8 h of reaction.

Hybrid lead halide perovskites continue to attract interest for use in optoelectronic devices such as solar cells and light-emitting diodes. Although challenging, the replacement of toxic lead in these systems is an active field of research. Recently, the use of trivalent metal cations (Bi3+ and Sb3+) that form defect perovskites A3B2X9 has received great attention for the development of solar cells, but their light-emissive properties have not previously been studied. Herein, an all-inorganic antimony-based two-dimensional perovskite, Cs3Sb2I9, was synthesized using the solution process. Vapor-anion-exchange method was employed to change the structural composition from Cs3Sb2I9 to Cs3Sb2Br9 or Cs3Sb2Cl9 by treating CsI/SbI3 spin-coated films with SbBr3 or SbCl3, respectively. This novel method facilitates the fabrication of Cs3Sb2Br9 or Cs3Sb2Cl9 through solution processing without the need of using poorly soluble precursors (e.g., CsCl and CsBr). We go on to demonstrate electroluminescence from a device employing Cs3Sb2I9 emitter sandwiched between ITO/PEDOT:PSS and TPBi/LiF/Al as the hole and electron injection electrodes, respectively. A visible-infrared radiance of 0.012 W·Sr-1·m-2 was measured at 6 V when Cs3Sb2I9 was the active emitter layer. These proof-of-principle devices suggest a viable path toward low-dimensional, lead-free A3B2X9 perovskite optoelectronics.

CeO2 nanorods supported nickel catalysts were prepared by wetness impregnation method, using nickel nitrate and nickel chloride as nickel sources. The dried catalyst precursors were decomposed either by thermal calcination or glow discharge plasma technique. The effects of precursor decomposition methods and nickel sources on the catalytic performance of glycerol steam reforming were then investigated. Characterization and catalytic results showed that glow discharge plasma treatment instead of thermal calcination enhanced the nickel dispersion, improved the Ni-Ce interaction and led to the formation of Ni-O-Ce composite, which could both enhance the H2 selectivity and restrain the coke deposition during reaction. Thus, no deactivation was observed on the two plasma treated catalysts throughout the tests. Nickel source may influence both rate of particle sintering and carbonaceous deposition during reaction; fast nickel sintering but slower coke deposition was found on the catalysts prepared from nickel chloride, and coke deposition was more detrimental to active sites decrease than nickel sintering.

This study aims to assess and determine the oral-administration of probiotic, Lactobacillus pentosus BD6 on growth performance, immunity and disease resistance of white shrimp, Litopenaeus vannamei. Lac. pentosus BD6 effectively inhibited the growth of aquatic pathogens, which was used in the test. Shrimp were fed with the control diet (without probiotic supplement) for 60 days and the probiotic-containing diets at 107, 108, 109, and 1010 cfu kg−1, respectively. Shrimp fed with the diet containing probiotic at the doses of 109−10 cfu kg−1 showed significant increase in growth performance as well as feed efficiency than that of the control. After a challenge test with Vibrio alginolyticus, shrimp fed with a probiotic diet at a dose of 1010 cfu kg−1 showed a significantly lower mortality as compared to the control and that of shrimp fed the diet containing probiotic at the levels up to 107−8 cfu kg−1. In addition, a therapeutic potential of Lac. pentosus BD6 was discovered because the cumulative mortalities of shrimp fed with probiotic and pathogen V. parahaemolyticus simultaneously were significantly lower when compared to control shrimp. Probiotic in diet at a dose of 109−10 cfu kg−1 significantly increased PO activity of shrimp, while shrimp receiving probiotic at the doses of 108−10 cfu kg−1 showed significant increase in lysozyme activity and phagocytic activity. Shrimp fed with the diet containing probiotic at the level of 1010 cfu kg−1 also indicated higher gene expression of prophenoloxidase (proPO) I, but not proPO II, lipopolysaccharide and β-1,3-glucan-binding protein and penaeidin 4. Analysis of the bacterial microbiota of the shrimp intestine revealed that oral administration of probiotic increased the relative abundance of beneficial bacteria and reduced the abundance of harmful pathogenic bacteria in the gut flora of shrimp. Despite no statistically significant difference, an analysis of microbial diversity recorded higher species richness, Shannon–Weaver diversity index and evenness in the probiotic group, compared to the control group. It was concluded that Lac. pentosus BD6 has great antibacterial ability against a wide range of pathogens and has therapeutic potential to reduce the mortality of shrimp infected with V. parahaemolyticus. Additionally, dietary Lac. pentosus BD6 at the level of 1010 cfu kg−1 was recommended to improve growth performance, immunity and disease resistance of shrimp against V. alginolyticus.

The mechanical properties of nucleic acids underlie biological processes ranging from genome packaging to gene expression, but tracing their molecular origin has been difficult due to the structural and chemical complexity. We posit that concepts from machine learning can help to tackle this long-standing challenge. Here, we demonstrate the feasibility and advantage of this strategy through developing a structure-mechanics statistical learning scheme to elucidate how local rigidity in double-stranded (ds)DNA and dsRNA may lead to their global flexibility in bend, stretch, and twist. Specifically, the mechanical parameters in a heavy-atom elastic network model are computed from the trajectory data of all-atom molecular dynamics simulation. The results show that the inter-atomic springs for backbone and ribose puckering in dsRNA are stronger than those in dsDNA, but are similar in strengths for base-stacking and base-pairing. Our analysis shows that the experimental observation of dsDNA being easier to bend but harder to stretch than dsRNA comes mostly from the respective B- and A-form topologies. The computationally resolved composition of local rigidity indicates that the flexibility of both nucleic acids is mostly due to base-stacking. But for properties like twist-stretch coupling, backbone springs are shown to play a major role instead. The quantitative connection between local rigidity and global flexibility sets foundation for understanding how local binding and chemical modification of genetic materials effectuate longer-ranged regulatory signals., The mechanical properties of nucleic acids underlie biological processes ranging from genome packaging to gene expression. We devise structural mechanics statistical learning method to reveal their molecular origin in terms of chemical interactions.

Here we achieved record-high >500 volumes/second two-photon imaging by improving lateral and axial scanning speed via 32-channel multifocal excitation/detection, and a tunable acoustic gradient-index lens, respectively. We developed a deconvolution process to reduce scattering-induced crosstalk in multifocal detection scheme, thus enabling whole brain imaging of Drosophila with millisecond and micrometer spatiotemporal resolution. Potential applications toward brain science include studying millisecond dynamics in a neuronal network, and resolving 3D microfluidics in blood vessels.

We demonstrate the hybrid integration of a lithium niobate microring resonator with a silicon nitride waveguide in the vertical configuration to achieve efficient light coupling. The microring resonator is fabricated on a lithium niobate on insulator (LNOI) substrate using photolithography assisted chemo-mechanical etching (PLACE). A fused silica cladding layer is deposited on the LNOI ring resonator. The silicon nitride waveguide is further produced on the fused silica cladding layer by first fabricating a trench in the fused silica while using focused ion beam (FIB) etching for facilitating the evanescent coupling, followed by the formation of the silicon nitride waveguide on the bottom of the trench. The FIB etching ensures the required high positioning accuracy between the waveguide and ring resonator. We achieve Q-factors as high as 1.4 × 107 with the vertically integrated device.

The understanding of nonlinear light–matter interactions at the nanoscale has fueled worldwide interest in upconversion emission for imaging, lasing, and sensing. Upconversion lasers with anti-Stokes-type emission with various designs have been reported. However, reducing the volume and lasing threshold of such lasers to the nanoscale level is a fundamental photonics challenge. Here, we demonstrate that the upconversion efficiency can be improved by exploiting single-mode upconversion lasing from a single organo-lead halide perovskite nanocrystal in a resonance-adjustable plasmonic nanocavity. This upconversion plasmonic nanolaser has a very low lasing threshold (10 μJ cm⁻²) and a calculated ultrasmall mode volume (∼0.06 λ³) at 6 K. To provide the unique feature for lasing action, a temporal coherence signature of the upconversion plasmonic nanolasing was determined by measuring the second-order correlation function. The localized-electromagnetic-field confinement can be tailored in titanium nitride resonance-adjustable nanocavities, enhancing the pump-photon absorption and upconverted photon emission rate to achieve lasing. The proof-of-concept results significantly expand the performance of upconversion nanolasers, which are useful in applications such as on-chip, coherent, nonlinear optics, information processing, data storage, and sensing.

We demonstrate monolithic integration of an electro-optically (EO) tunable microring laser on lithium niobate on insulator (LNOI) platform. The device is fabricated by photolithography assisted chemo-mechanical etching (PLACE), and the pump laser is evanescently coupled into the erbium (Er3+) doped LN microring laser using an undoped LN waveguide mounted above the microring. The quality factor of the LN microring resonator is measured as high as 1.54x10^5 at the wavelength of 1542 nm. Lasing action can be observed at a pump power threshold below 3.5 mW using a 980 nm continuous-wave pump laser. Finally, tuning of the laser wavelength is achieved by varying the electric voltage on the microelectrodes fabricated in the vicinity of microring waveguide, showing an EO coefficient of 0.33 pm/V., Comment: 4 pages, 4 figures

The voltage controlled oscillator (VCO) of the frequency modulation continuous wave (FMCW)radar is usually non-linear, which causes the radar range resolution to decrease. The non-linearity of frequency sweep is one of the main problems that limit the range resolution of chirp continuous wave radar. Although the traditional method based on polynomial model can correct most of the nonlinear distortion in the system, it is difficult to suppress the paired echoes caused by periodic nonlinearity, and there is still a large space for improving the quality of range compression. We propose a novel method to measure the systematic phase errors which are required as input to the compensation algorithm. Simulation results show that the proposed algorithm can effectively eliminate the periodic phase error and significantly improve the quality of range compression.

We design a compact three-dimensional (3D) micromixer based on the Baker’s transformation concept and fabricate it in fused silica by ultrafast laser direct writing. One of the issues in the micromixer is the unbalanced mixing efficiencies between the center and boundary areas of the microfluidic channel. We overcome this problem by periodically exchanging the microstreams in the center and near the boundary which gives rise to improved mixing efficiency and uniformity. The performance of the fabricated micromixer is examined by mixing a blue and a yellow ink solution, showing efficient mixing with a high throughput.

Studying neural connections and activities in vivo is fundamental to understanding brain functions. Given the cm-size brain and three-dimensional neural circuit dynamics, deep-tissue, high-speed volumetric imaging is highly desirable for brain study. With sub-micrometer spatial resolution, intrinsic optical sectioning, and deep-tissue penetration capability, two-photon microscopy (2PM) has found a niche in neuroscience. However, current 2PM typically relies on slow axial scan for volumetric imaging, and the maximal penetration depth is only about 1 mm. Here, we demonstrate that by integrating two gradient-index (GRIN) lenses into 2PM, both penetration depth and volume-imaging rate can be significantly improved. Specifically, an 8-mm long GRIN lens allows imaging relay through a whole mouse brain, while a tunable acoustic gradient-index (TAG) lens provides sub-second volume rate via 100 kHz ∼ 1 MHz axial scan. This technique enables the study of calcium dynamics in cm-deep brain regions with sub-cellular and sub-second spatiotemporal resolution, paving the way for interrogating deep-brain functional connectome.

The electrode, as one of the key components in supercapacitors, has a pivotal effect on the overall performances. In this work, a series of composite electrode materials are proposed via the combination of nickel aluminum layered double hydroxides (NiAl-LDHs) and carbon nanotubes (CNTs). To begin with, materials with different ratios of the two compositions are fabricated with a coprecipitation method. After that, various characterization methods indicate that the NiAl-LDH/CNT composites exhibit an irregular thin platelet structure with a well-constructed conductive network inside. Furthermore, the effect of the CNT ratio on the electrochemical property is subsequently investigated, which proves that the conductive network of CNTs is beneficial for the transport of the electrons and strengthens the platelet structure. The results show that when the amount of CNTs reaches 1.5 wt %, it can yield a high specific capacitance of 2447 F g-1 at 2 A g-1, with a good cycling stability of 90.1% after 2500 cycles, indicating high application potential in positive electrodes of pseudocapacitors. The synergistic effects of NiAl-LDHs and CNTs are thought to be the main reasons for the good properties of NiAl-LDHs/CNTs composites.

In this study, we examined DNA sequences of bacteria isolated from goldfish intestine and identified the species in collaboration with the Food Industry Research & Development Institute of Taiwan. One bacterial species, Enterococcus avium, was selected for evaluation of its antimicrobial effects and probiotic function. The antimicrobial effects of feed containing E. avium were investigated in tilapia challenged with Streptococcus agalactiae. We found that E. avium inhibits a variety of pathogens, including gram-positive and gram-negative bacteria, with the strongest inhibition observed for Pseudomonas aeruginosa. Moreover, E. avium cells disrupted by sonication retained their antibacterial effects. By treating the sonicated cells at different temperatures or pH, we discovered that heating the cells above 75 °C resulted in the loss of their inhibitory effects. Moreover, E. avium pellets resuspended at pH 3.0 exhibited strong bacteriostatic activity, whereas E. avium pellets resuspended in solutions of pH > 10 had diminished antimicrobial activity. Tilapia fed once or twice a day with high concentrations (1 × 1010, 1 × 109, or 1 × 108 cfu/g) of sonicated or viable bacteria exhibited higher growth rates than both the control group and the experimental group fed 1 × 107 cfu/g. In addition, tilapia fed high concentrations of sonicated bacteria twice a day exhibited a higher survival rate than fish fed viable bacteria after a challenge with S. agalactiae.

Metal halide perovskites having three-dimensional crystal structures are being applied successfully in various optoelectronic applications. To address their most challenging issues—instability and toxicity—without losing efficiency, lower-dimensional perovskites appear to be promising alternatives. Recently, two-dimensional (2D) perovskite solar cells have been developed exhibiting excellent photostability and moisture-stability, together with moderate device efficiency. This review summarizes the photophysical properties and operating mechanisms of 2D perovskites as well as recent advances in their applications in solar cell devices. Also presented is an agenda for the next-stage development of stable perovskite materials for solar cell applications, highlighting the issues of stability and toxicity that require further study to ensure commercialization.

We report on a comparative study of strong-field ionization of alkaline-earth-metal atoms by intense femtosecond laser pulses from near-infrared to midinfrared wavelengths. By collecting the ionization signals only produced within the central portion of the laser focus, the focus volume effect is largely reduced and the saturation intensities for different alkaline-earth-metal atoms are reliably determined, which permits us to directly test the strong-field-ionization theories. We demonstrate that the Perelomov-Popov-Terent'ev model accurately predicts the experimental ionization yields and saturation intensities in general for arbitrary values of the Keldysh parameter, while the Ammosov-Delone-Krainov simulations agree with the experiments for the tunneling-ionization regime and also for the regime when the Keldysh parameter is around 1. Our work presents benchmark data for strong-field ionization of alkaline-earth metals over a broad range of laser parameters and confirms the validity of Keldysh's picture for such atoms.

Dissolution of lithium polysulfide (LiPS) into the electrolyte during discharging, causing shuttling of LiPS from the cathode to the lithium (Li) metal, is mainly responsible for the capacity decay and short battery life of lithium-sulfur batteries (LSBs). Herein, we designed a separator comprising polypropylene (PP) coated with MoO3 nanobelts (MNBs), prepared through facile grinding of commercial MoO3 powder. The formation of Li2Sn-MoO3 during discharging inhibited the polysulfide shuttling; during charging, Li passivated LixMoO3 facilitated ionic transfer during the redox reaction by decreasing the charge transfer resistance. This dual-interaction mechanism of LiPS-with both Mo and the formation of LixMoO3-resulted in a substantially high initial discharge capacity at a very high current density of 5C, with 29.4% of the capacity retained after 5000 cycles. The simple fabrication approach and extraordinary cycle life observed when using this MNB-coated separator suggest a scalable solution for future commercialization of LSBs.

The paper reports a microwave assisted rapid synthesis of NiCo2O4@CNTs composite for the first time. Ultrafine NiCo2O4 nanoparticles approximately 6–10 nm in size dispersed uniformly along the CNTs walls are obtained. Interestingly, nanosheets structure is formed in the absence of CNTs. The distinctive morphology difference is attributed to the different nucleating and growing mechanisms. Due to the small NiCo2O4 nanoparticle size derived from microwave enabled fast synthesis and the unique 1D nanostructure, the NiCo2O4@CNTs composites materials exhibit more excellent lithium storage performance than that of counterparts.

Femtosecond laser-induced chemical etching (FLICE) has proved itself a powerful approach when attempting to fabricate three-dimensional (3D) microstructures in glass, whereas maintaining a high spatial resolution in fabricating samples of great heights/thicknesses is challenging due to the diffraction nature of light waves. Here, we demonstrate the fabrication of macro-scale 3D glass objects of large heights up to ~3.8 cm with a well-balanced lateral and longitudinal resolution of ~20 μm using the FLICE. Moreover, a freeform hand printed with embedded blood vessel system has been produced. The remarkable accomplishments are achieved by revealing an unexplored regime in the interaction of ultrafast laser pulses with fused silica, which gives rise to depth-insensitive focusing of the laser pulses and polarization-independent selective etching inside fused silica. We examine the difference in the plasma dynamics between interactions of picosecond and femtosecond laser pulses with fused silica glass.

Metal-organic frameworks (MOFs) derived metal@porous carbon showed good performance in peroxymonosulfate (PMS) activation for refractory organic chemical degradation from aqueous. However, the effect of structure and physical-chemical properties of metal@porous carbon on PMS activation and its involved reaction mechanism were still unclear. Herein, Fe@porous carbon derived from MOF MIL-53(Fe) was used as target, to discuss the role of NH2-group incorporation on the development of structure and physical-chemical properties of obtained Fe@porous carbon, and reaction mechanism for PMS activation. The incorporation of NH2-group significantly decreased the synthesis temperature of Fe@porous carbon and increased the encapsulation of Fe0 in the porous carbon. Furthermore, the addition of nitrogen in porous carbon and rigid encapsulation structure reduced the defects of the Fe@porous carbon. These improvements of the structure and chemical properties were favored for enhancement of the catalytic activity and stability of the obtained Fe@porous carbon in the activation of PMS. Electron paramagnetic resonance (EPR) experiments indicated that SO4 −, OH and 1O2 were involved. The radical pathway involving SO4 − and OH was the prevailing pathway while the nonradical pathway involving 1O2 was the recessive pathway. Based on intermediate identification, the degradation pathway of acyclovir (ACV) was proposed as SO4 − and OH derived process, and eight of intermediates were first reported. It was interesting to note that iron species, carbon structure, and nitrogen element in the catalysts derived from MIL-53(Fe) or NH2-MIL-53(Fe) clearly showed different role and reaction pathway. This work not only provided an efficient Fe@N-doped porous carbon for activation PMS to degrade refractory organic chemicals for water purification, but also suggested a valuable insight for the design of metal@porous carbon derived from MOF.

Sulfate radical-based photo-Fenton (SR-photo-Fenton) reaction, assisted by visible light irradiation, was achieved by CuBi2O4 and its composites with α-Bi2O3 for refractory chemical degradation in aqueous solution. Herein, this catalyst was fabricated by a sol-gel method and the fabrication conditions, including calcination temperature and molar ratio of Cu/Bi, were optimized according to the crystal phase composition, catalytic activity and toxic copper ion leaching. The optimal calcination temperature was 500 °C and molar ratio of Bi to Cu was 2.0. The catalyst containing CuBi2O4 and α-Bi2O3 showed a higher density of surface OH which might be the key surface active site than pure CuBi2O4. The influence of initial solution pH, PMS concentration, catalyst dosage and catalyst reuse on rhodamine B (RhB) degradation was investigated. Importantly, calcination at 500 °C reverted the catalytic activity of catalyst. Results of electron paramagnetic resonance, competitive radical experiments and surface chemical property characterization demonstrated that the reaction mechanism of this novel SR-photo-Fenton reaction is a combination of interface and solution reactions. In the interface reaction, the transfer of photogenerated electron/hole pairs drives the decomposition of PMS to produce SO4 − and OH. Furthermore, the cycling of Cu(I)/Cu(II) facilitated effective PMS activation to generate free radical that was responsible for the degradation of RhB. The second order reaction rate constant between RhB and SO4 − was determined to be 0.595–6.436 × 1010 M−1 S−1 based on the chemical reaction kinetics of radical, which was a first and important report for SO4 − chemistry.

Different amounts of nickel were loaded on carbon nanotubes (CNTs) by an impregnation method and characterized by N2 adsorption/desorption isotherms, X-ray diffraction, X-ray photoelectron spectros...

Wavy carbon nanotubes (CNTs) are ubiquitously present in high-aspect-ratio CNT arrays used in advanced device applications. This paper investigates the effective modulus and natural frequency of wavy CNTs that have random, sinusoidal, or helical structures. Parameters such as loading deviation angle, boundary condition, and low shear modulus are considered. It was found that loading deviation could cause 3–4 orders modulus reduction for sinusoidal and helical CNTs at small waviness ratio. In contrast, there is slight modulus enhancement by a small loading deviation for randomly wavy CNTs. By applying pined or fixed boundary condition at the loading end, the moduli of wavy CNTs may be enhanced by up to 4 orders in magnitude. As another critical parameter, low shear modulus (∼50 MPa) may cause significant modulus reduction only for helical CNTs, about 2 orders of magnitude due to large shear and torsional deformation. The natural frequencies of wavy CNTs were also computed, showing that helical CNTs generally have lower frequency than other wavy CNTs. Furthermore, very low shear modulus could result in significant frequency reduction for helical CNTs, but has limited effect on random or sinusoidal CNTs. With the high sensitivity to shear modulus, helical CNTs are thus more desirable in the electric-field-induced resonance testing used for CNT property characterization. The findings on the properties of wavy CNTs can provide fundamental guidelines for the design of CNT arrays or CNT-based composites.

Chirality is a fundamental property of biochemical molecules and often dictates their functionality. Conventionally, molecular chirality is studied by linear optical activity effects. However, poor contrast and artifacts due to anisotropy limit such studies to purified molecules not in their original microenvironments, potentially modifying their conformations. Here, we demonstrate that resonant second-harmonic-generation circular dichroism (SHG-CD) microscopy provides not only tissue imaging with improved chiral contrast, but also molecular chirality information of collagen, the most abundant protein in mammals, at its native state. Gradual protein denaturation shows that the resonant SHG-CD is dominated by the microscopic chirality related to collagen structures smaller than the spatial resolution of the microscope, i.e. to the protein conformation and microfibril organization, while the effects due to fiber orientation/anisotropy are mostly responsible of the non-resonant part. This result agrees well with a simple and intuitive model we propose to explain the resonant behavior and the consequent numerical SHG-CD simulations. Our results demonstrate the possibility to study molecular chirality in intact bio-tissues with nearly-unity contrast and sub-micrometer resolution, which will be useful in a broad range of biological and biochemical applications acceptedVersion

A superparamagnetic graphene oxide (GO)/Fe3O4 nanocomposite (MGO) was prepared by a facile in situ co-precipitation strategy, resulting in a prospective material for the application of graphene oxide in wastewater treatment. MGO was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The prepared adsorbent showed a high adsorption efficiency relevant to the purification of dye-contaminated wastewater and could be readily magnetically separated. The maximum adsorption capacity was ca. 546.45 mg g−1 for the common cationic dye methylene blue (MB) and ca. 628.93 mg g−1 for the anionic dye Congo red (CR). The adsorption processes fit the pseudo-second-order kinetic model well, which revealed that these processes may involve the chemical interaction between adsorbate and adsorbent. The thermodynamic parameters indicated that the adsorption reaction was an endothermic and spontaneous process. Furthermore, the prepared magnetic adsorbent had a wide effective pH range from 5 to 11 and showed good stability after five reuse cycles. The synthetic MGO showed great potential as a promising adsorbent for organic contaminant removal in wastewater treatment.

The rapid development of perovskite solar cells (PSCs) has triggered a quest for lead (Pb)-free alternatives to improve their commercial viability. One such non-lead material, the methylammonium antimony iodide zero-dimensional dimer (CH3NH3)3Sb2I9, was reported recently, but with a low photo conversion efficiency (PCE) resulting from its poor surface morphology (many pinholes; amorphous nature). In this study, we employed anti-solvent treatment to improve the surface morphology of the Sb-based dimer by speeding up heterogeneous nucleation. We also incorporated an interlayer that acted as a favorable hydrophobic scaffold for the growth of large-grain (CH3NH3)3Sb2I9 crystals, thereby decreasing the number of the voids and increasing the film quality. We achieved a champion efficiency of 2.77%—a large improvement over the efficiencies reported previously. Using the techniques employed herein to prepare new perovskite-like materials, Sb-based photoabsorbers might become promising replacements for Pb-based perovskites.

A hybrid catalyst system consisted of MWCNT and Co-TiO2 through simple physical mixing was applied for peroxymonosulfate activation for antipyrine degradation. With 2 mM peroxymonosulfate, the removal rate of antipyrine is significantly increased from 53.24% and 86.23% to 100% in the presence of same weight of 0.2 g/L MWCNTs, Co-TiO2, and MWCNTs/Co-TiO2 (half/half) mixture, respectively in 12 min. The influence of various parameters, including the ratio of Co-TiO2/MWCNT, catalyst dose, peroxymonosulfate dose, antipyrine concentration, and initial pH, were further investigated in detail. The underlying catalytic mechanism of the synergistic effect was unraveled by quenching tests and EPR analysis. It was attributed to the electrons tranferration between Co-TiO2 and MWCNT, and the acceleration of Co3+/Co2+ by generated superoxide. This work not only provides a novel and efficient method of pharmaceutical wastewater treatment, but also reveals a new perspective to use the catalyst more efficiently.

Charge-selective contacts can play a critical role in enhancing the efficiency of perovskite solar cells (PSCs). In this study, we employed fluorine-functionalized graphene (FGr) layers having finely tunable energy levels as hole transport layers (HTLs) to improve the power conversion efficiency (PCE) and stability of inverted PSCs. The non-wetting surface of the FGr enhanced the crystallinity of organic–inorganic perovskites films with large aspect ratios, relative to that of poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS). Combining the high work function of the HTL interface with the enhanced crystallinity and limited grain boundary area dramatically decreased the charge recombination losses in organic–inorganic trihalide perovskite (OTP) films. Thus, when incorporating FGr HTLs in inverted PSCs, the best PCE reached 19.34%—the highest efficiency reported to date for any PSC featuring a functionalized graphene HTL. Furthermore, we used this HTL to prepare flexible PSCs and obtained a highest efficiency of 17.50%. Therefore, this highly applicable and facile interface strategy using functionalized graphene HTLs provides stable PSCs displaying high PCEs.

A photocatalyst composed of Zn–TiO2 and Cu–TiO2 through simple physical mixing was used to activate persulfate(PS) for Bisphenol S (BPS) degradation. Zn–TiO2 and Cu–TiO2 were prepared with a sol gel method and were characterized by X-ray diffraction (XRD), Raman, Transmission electron microscope (TEM), Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The two catalysts have shown an obvious synergistic effect in the photocatalytic degradation process. When 5 mM persulfate and 0.3 g/L catalyst were used, the removal rate of mixed catalyst (0.2 g/L Zn–TiO2 and 0.1 g/L Cu–TiO2) is 100 % in 18 min, which is significantly better than that of 0.3 g/L Zn–TiO2(58 %) and 0.3 g/L Cu–TiO2(90 %). Typically, the effects of various operation parameters, including the ratio of Cu–TiO2/Zn–TiO2, catalyst dosage, persulfate dosage, initial concentration of BPS, and initial solution pH, were examined. Reactive oxygen species (ROS) in the UV/mixed catalyst/PS process was identified by scavenger and electron paramagnetic resonance (EPR) tests. The superoxide radicals generated by both Zn–TiO2 and the hydrolysis of persulfate in the system could accelerate the Cu (II)/Cu(I) redox cycles and results in the synergistic effect. This study proposed a new and effective way to improve the reaction by simply combining two catalysts, and unraveled the mechanism behind the synergistic effect, which could provide new ideas to use the catalyst more effectively for wastewater treatment or other areas.

A novel n-n type WC/BiOCl binary photocatalyst was synthesized, and applied to sulfamethoxazole (SMX) degradation. The physical and photoelectric properties of the WC/BiOCl were characterized by various experimental and calculational methods. An intimate interfacial contact between WC and BiOCl was identified, which help to reduce the aggregation of BiOCl and more importantly, build an internal electrical field between WC and BiOCl. It is interesting to find that the WC layer(s) can help to reduce the interfacial charge transfer resistance and act as electron transfer and storage sites. Subsequently, the holes are engaged in the oxidation of SMX by WC/BiOCl. Additionally, WC/BiOCl photocatalyst has more reactive sites and absorbs more incident photons compared with pure BiOCl. Quenching and electron spin resonance (ESR) experiments indicate that O2·- is the main active species, holes and OH• are also involved. The degradation pathway of SMX and the enhancing mechanism for the photodegradation through the combination of WC and BiOCl were explored. This work provides a novel binary photocatalyst for SMX degradation.

Microheaters as tiny in-situ heating elements are of great importance for developing many thermal-sensitive microdevice applications. A facile technique for the fabrication of embedded metallic microheaters, microheater arrays, and microthermal sensors based on the combination of femtosecond laser-assisted chemical etching, electroless plating, and mechanical polishing has been proposed. With the proposed technique, uniform and controllable temperature distributions in the central area of fabricated microheaters have been achieved. Moreover, flexible manipulation of localized temperature in a microheater array as well as precise calibration of microheaters based on a simultaneously integrated microthermal sensor has been demonstrated. Furthermore, precise control of temperature in glass channels and acceleration of a chemical reaction in microfluidics using monolithically integrated microheaters have been realized, showing great potential for developing laser manufacturing of multifunctional thermal-control microfluidic devices.