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The fast and high response detection of neurotoxic H2S is of great importance for the environment. In this paper, directly electrospinning technology on the ceramic tube is developed to improve the response of H2S detector based on superlong SnO2 fibers. The submillimeter continuous fibers are deposited directly on ceramic tubes by in-situ electrospinning method and can keep morphology of fibers during calcination. By employing this technology, CuO-doped SnO2 fiber H2S detectors are fabricated, and 10% atom CuO-doped SnO2 H2S detector shows the highest response of 40 toward 1 ​ppm ​H2S at 150 ​°C while the response is only 3.6 for the H2S detector prepared in traditional route. In addition, the in-situ electrospinning H2S detectors show faster response and recovery compared to the H2S detectors fabricated by the conventional way. The high and fast response of H2S detectors based on in-situ electrospinning can be ascribed to the continuous fiber structure and CuO modification. The present in-situ electrospinning technology may provide a new strategy for the development of other gas-detectors and bio-detectors with fast and high response.

Micro-Electro-Mechanical Systems (MEMS) micro-mirrors have shown great potential in consumer applications, such as Light Detection and Ranging (LiDAR) devices and portable laser projectors. The LiDAR based on electromagnetic MEMS micro-mirror is usually exposed to vibration loads for autonomous vehicles, which results in the necessity for the destructive reliability assessment of micromirrors under vibration environment, but such studies are rarely reported. This paper explores the destructive reliability of electromagnetic MEMS micromirror under vibration environment according to the JESD22-B103B standard. The reliability evaluation is conducted by experimental tests, finite element stress analysis and theoretical dynamic response analysis. Micromirrors are tested under sweep excitation, and they are failed with the vibration level of around 33 g. The failure and stress analysis demonstrate that the crack fracture is located at the root of the slow axis. The nonlinear relationship between the peak displacement of the balance frame and acceleration levels is investigated through theoretical analysis. The nonlinearity of stiffness hardening is induced by the axial tensile strain of the beam, which contributes to the displacement-reduction of the gimbal. This work provides some valuable suggestions for the optimization design of MEMS micromirrors to improve the acceleration tolerance level in vibration environment.

In daily operations, there are lots of blade disk structures operating in water, e.g., hydraulic turbines and pumps, whose dynamic behavior may be severely affected by the added mass effect. Their mode shape change problem from vacuum to water due to the added mass effect has been studied in this paper. The added mass effect of simplified blade disk structures submerged in still water has been studied numerically first in this paper. Acoustic fluid–structure interaction technology has been used to simulate the fluid and structure coupling effect. Through comparing the strain energy percentage of the disk part in water with those in air under different disk material densities, it showed that different parts of the submerged blade disk structures can suffer from different average added mass factors, which makes the modal shapes of some modes with strong blade disk interactions change a lot from vacuum to water, thus produces a large influence on the optimal design of submerged blade disk structures. Based on the conclusions of the simplified model, the situation of a Francis turbine runner model was investigated, and the results fit the conclusions on the simplified model very well.

A simple and effective method for constructing highly efficient oxygen reduction catalysts with trace amount of isolated cobalt was firstly developed by the pyrolysis of Co-centered polyoxometalate@metal-organic framework (Co-POM@MOF). The Co-centered polyoxometalate ([CoW12O40]6−) was confined in the well-defined void space of ZIF-8 to achieve homogeneous dispersion of polyoxoanions, where the isolated Co centers were well surrounded by the W-O shell and ZIF-8 framework. The Co-POM@MOF-derived N-doping porous carbon (Co-W-NC) with trace cobalt content was facilely prepared by the pyrolysis of the Co-POM@MOF under Ar atmosphere. The single dispersion of polyoxoanions in the metal-organic framework with complete separation of Co center surrounding by W-O shell and ZIF-8 framework ensures the uniform dispersion of Co atoms, confirmed by the Fourier transform extended X-ray absorption fine structure measurement. The Co-W-NC composite catalysts exhibit high performance for oxygen reduction reactions with a half-wave potential of 0.835 V in 0.1 mol/L KOH solution with excellent durability, which is much superior to that of the control samples derived from the [PW12O40]@ZIF-8, and the commercial Pt/C. This work highlights a new insight for constructing highly efficient catalysts via the introduction of metal-centered polyoxometalate into metal-organic framework following the high temperature treatment process.

Stable organic luminescent radicals are a special class of compounds integrating optical, electrical, and magnetic properties. Luminescent radicals not only have potential applications in the field...

Compared with a copper wire electrode, molybdenum wire with a poor conductor is usually used as the electrode in high speed wire-cut electrical discharge machining (HSWEDM), so the resistance of an ultra-fine wire cannot be ignored. To study the differences of discharge characteristics between the ultra-fine wire and the conventional diameter wire, the continuous discharge waveform of two kinds of wire electrodes was compared. It was found that there was a multi-channel discharge phenomenon in the discharge waveform cutting by ultra-fine wire. Through the establishment of a discharge equivalent circuit model and the simulation analysis of the electrostatic field, it was found that the reason why ultra-fine wire is easy to form multi-channel discharge phenomenon is that the potential difference between the wire and the workpiece increased linearly along the axis of the wire. Besides, etching products like metal particles will distort the electric field between the electrodes. Both of them make it easy to form a multi-channel discharge in machining. The results show that the distributions of the equivalent resistance and the peak current are affected by the multi-channel discharge position. Multi-channel discharge can disperse energy and increase effective discharge frequency. Compared with the 0 mm spacing, at a spacing of 100 mm, the machining efficiency increases by 8.7%, the surface roughness decreases by 37.7%, and the average recast layer thickness decreases by 46.6% under the condition of ultra-fine wire-EDM.

Thermally activated delayed fluorescent (TADF) materials capable of efficient solution-processed non-doped organic light-emitting diodes (OLEDs) are of important and practical significance for further development of OLEDs. In this work, a new electron-donating segment, 2,7-di(9H-carbazol-9-yl)-9,9-dimethyl-9,10-dihydroacridine (2Cz-DMAC), was designed to develop solution-processable non-doped TADF emitters. 2Cz-DMAC can not only simultaneously increase the solubility of compounds and suppress harmful aggregation-caused quenching, but also efficiently broaden the delocalization of the highest occupied molecular orbital and promote the reverse intersystem crossing process. Three new TADF emitters, 2-(2,7-di(9H-carbazol-9-yl)-9,9-dimethylacridin-10(9H)-yl)dibenzo[b,d]thiophene 5,5-dioxide (2Cz-DMAC-BTB), 2-(2,7-di(9H-carbazol-9-yl)-9,9-dimethylacridin-10(9H)-yl)-9H-thioxanthen-9-one (2Cz-DMAC-TXO), 2-(2,7-di(9H-carbazol-9-yl)-9,9-dimethylacridin-10(9H)-yl)thianthrene 5,5,10,10-tetraoxide (2Cz-DMAC-TTR), were developed by using 2Cz-DMAC segment as the electron-donor. As anticipated, the solution-processed non-doped OLEDs employing 2Cz-DMAC-BTB, 2Cz-DMAC-TXO and 2Cz-DMAC-TTR as the emitters respectively exhibited green, orange and red emissions with maximum external quantum efficiencies of 14.0%, 6.6% and 2.9%. These results successfully demonstrate the feasibility and convenience of developing efficient solution-processable non-doped TADF emitters based on 2Cz-DMAC segment.

Covalent organic frameworks (COFs) have been recognized as a new type of promising visible-light-driven photocatalysts for H2 evolution, while it still is a key point to facilitate the separation and transfer of photoinduced charges for further enhancing their activities. In this work, we fabricated a new type of ternary Pt/rGO/COF photocatalysts with Pt cocatalyst precisely anchored on rGO serving as electron collector for largely enhanced H2 evolution. A series of ternary hybrid materials were obtained via one-pot photoreduction of Pt4+ and GO under visible-light irradiation in a solution the same as photocatalytic H2 evolution reaction and simultaneous self-assembling of rGO/COF heterostructure. No need isolation, the synthetic system could be further used for photocatalytic H2 evolution reaction and the results show the H2 evolution rate of Pt/rGO(20%)/TpPa-1-COF hybrid material is 19.59 mmol·g−1·h−1, 6.51 times higher than that of Pt/TpPa-1-COF. The essential role of the exclusively distributed Pt nanoparticles on rGO to the high H2 evolution activity was confirmed by various comparisons of activity for the samples with diverse Pt distribution.

Incorporation of nanoparticles into polymer blend to obtain finely dispersed morphology has been considered as an effective strategy to prepare nanocomposites. Owing to the renewable and degradable characters, cellulose nanocrystals (CNCs) have been proposed to tailor the phase morphology of poly (L-lactic acid) blend for producing high-performance fused deposition modeling (FDM) consumables. However, the main challenge associated with the ternary systems is the dispersion of the highly hydrophilic CNCs in nonpolar PLLA blend by industrial melt blending without involving solution. Herein, with polyvinyl acetate (PVAc) modified CNCs powder (a mixture of PVAc grafted from CNCs and PVAc homopolymer latex), the selective dispersion of CNCs in PLLA has been achieved by simple melt processing of PLLA/TPU (polyether polyurethane)/CNCs blend. This results in the ultra-fine TPU droplets at nanoscale in PLLA and improves the melt processibility of composites in FDM due to the decreased viscosity ratio of the dispersed/matrix and the enhanced melt elasticity of PLLA. Combined with the intensive shear and continuous stretch effect during FDM, aligned TPU nanofibers (TNFs) were in-situ formed along the elongational flow direction during deposition, which in turn contributed to the improvement of PLLA/TPU/CNCs with 5 wt% filler loading in tensile ductility by 418%, inter-layer adhesion strength and notched impact toughness by 261% and 210%, respectively, as well as achieved good dimensional accuracy and very fine surface quality.

Developing environmentally friendly methods to produce hydrogen peroxide (H2O2) has received increasing attention. Photocatalysis has been proved to be a sustainable technology for H2O2 production. Herein, the novel non-metal elements (B, P, and S) doped g-C3N4 tubes (B-CNT, P-CNT, and S-CNT) photocatalysts were obtained via a hydrothermal synthesis followed by thermal polymerization. By adjusting the precursor, the yield of g-C3N4 tubes (CNT) materials has been greatly improved. The as-prepared B-CNT, P-CNT, and S-CNT photocatalysts show an enhanced photocatalytic H2O2 production with the formation rate constants values of 42.31 μM min−1, 24.95 μM min−1, and 24.22 μM min−1, respectively, which is higher than that of bulk CN (16.40 μM min−1). The doped B, P, S elements significantly enhanced the photocatalytic activity by adjusting their electronic structures and promoting the separation of electron-hole carriers. The results have shown great potential for the practical application of CNT photocatalysts.

By polymerization of gadolinium methacrylate (Gd (MAA)3), lead methacrylate (Pb(MAA)2) and methyl methacrylate (MMA), Gd and Pb were chemically bonded into polymers. The X-ray shielding performance was evaluated by Monte Carlo simulation method, and the results showed that the more metal functional organic monomer, the better the shielding performance of terpolymers. When the X-ray energy is 65 keV, Gd (MAA)3-containing polymers have better shielding performance than Pb(MAA)2-containing polymers. Gd could compensate for the weak absorption region of Pb. Therefore, polymers containing both Gd and Pb enhanced shielding efficiency against X-ray in various low-energy ranges. For obtaining terpolymers with uniform monomer compositions, the relationship between the monomer composition of the terpolymers and the conversion level was optimized by calculating the reactivity ratios. The value of reactivity ratios of r (Gd (MAA)3/Pb(MAA)2), r (Pb(MAA)2/Gd (MAA)3), r (Gd (MAA)3/MMA), r (MMA/Gd (MAA)3), r (Pb(MAA)2/MMA) and r (MMA/Pb(MAA)2) was 0.483, 0.004, 0.338, 2.508, 0.255, 0.029. The terpolymers with uniform monomer composition could be obtained by controlling the monomer compositions or conversion levels. The results can provide new radiation protection materials and contribute to the improvement in nuclear safety.

The cutting process of titanium alloy Ti-6Al-4 V is a complex thermomechanical coupling process with high temperature and high strain rate. In this paper, the modified Johnson–Cook (JCM) constitutive model considering strain-temperature coupling and high temperature dynamic crystallization is established, and the modified JC constitutive model is compiled based on the user subroutine VUMAT of ABAQUS. The 3D milling finite element simulation model of titanium alloy frame thin-walled parts is established, and the stress field, temperature field, milling force, and workpiece deformation are simulated and analyzed. The results show that the modified JC constitutive model improves the simulation accuracy by 4.3% and can more accurately describe the mechanical behavior of Ti-6Al-4 V alloy thin-walled parts in the cutting process.

The early detection of volatile organic compounds (VOCs) is crucial for sustainable development. Improving the binding properties of crystalline materials for special VOC guests is a tough challeng...

Electrochemical nitrogen reduction reaction (NRR) under ambient conditions is highly desirable to achieve sustainable ammonia (NH3) production via an alternative carbon free strategy. Single-atom catalysts (SACs) with super high atomic utilization and catalytic efficiency exhibit great potential for NRR. Herein, a high-performance NRR SAC is facilely prepared via a simple deposition method to anchor Au single atoms onto porous β-FeOOH nanotubes. The resulting Au-SA/FeOOH can efficiently drive NRR under ambient conditions, and the NH3 yield reaches as high as 2,860 µg·h−1·mgAu−1 at −0.4 V vs. reversible hydrogen electrode (RHE) with 14.2% faradaic efficiency, much superior to those of all the reported Au-based electrocatalysts. Systematic investigations demonstrate that the synergy of much enhanced N2 adsorption, directional electron export, and mass transfer ability in Au-SA/FeOOH greatly contributes to the superior NRR activity. This work highlights a new insight into the design of high efficient NRR electrocatalysts by combination of porous metal oxide matrix and highly active single-atom sites.

The built-up edge (BUE) usually occurs near the cutting edge with a negative rake angle at a low cutting speed. It serves as the cutting edge and imposes a great influence on the cutting process. However, the studies of BUE remain a challenge due to the difficulties in the BUE quantification, i.e., the experimental kinematics analysis as well as the numerical simulation of its thermo-mechanical characteristics. In this study, we propose an in situ imaging based thermo-mechanical analysis of the influences of BUE on the metal cutting process. The morphologies of the BUE and chip are identified through high-speed filming. With the captured images, the digital imaging correlation technique is implemented to derive the kinematic field during the cutting process. An incremental cutting process with a small cutting length is numerically simulated with the identified BUE and chip morphologies as inputs, in which the predicted cutting forces are validated successfully against the experimental measurements. With the experimental determination of the BUE and kinematic field, the formation of the BUE and its influences on the cutting process can be analyzed. It is experimentally observed that a cutting speed of 120 m/min leads to a minimum influence on the cutting process, for instance, smallest BUE with least occurrence rate as well as the least changes to the uncut chip thickness. In addition, the cutting temperature and stress fields in deformation zones exhibit remarkable BUE sharpening effects for different cutting speeds.

The unusual properties of quasicrystals (QCs) have attracted tremendous attention from researchers. In this paper, a semi-analytical solution is presented for the static response of a functionally graded (FG) multilayered two-dimensional (2D) decagonal QC rectangular plate with mixed boundary conditions. Based on the elastic theory of FG 2D QCs, the state-space method is used to derive the state equations composed of partial differential along the thickness direction. Besides, the Fourier series expansion and the differential quadrature technique are utilized to simulate the simply supported boundary conditions and the mixed boundary conditions, respectively. Then, the propagator matrix which connects the field variables at the upper interface to those at the lower interface of any homogeneous layer can be derived based on the state equations. Combined with the interface continuity condition, the static response can be obtained by imposing the sinusoidal load on the top surfaces of laminates. Finally, the numerical examples are presented to verify the effectiveness of this method, and the results are very useful for the design and understanding of the characterization of FG QC materials in their applications to multilayered systems.

Metal halide perovskites based on MX6 (M is metal and X is halogen) octahedra have developed into significant materials, extensively used in many fields, such as solid-state lighting, semiconductor, and nonlinear optics. However, the MX5 square pyramid-based hybrid metal halides beyond zero-dimensional (0D) polyhedrons and clusters are rarely reported. Herein, we reported two new isostructural hybrid antimony halides, namely (2cepyH)SbCl4 (1-Cl) and (2cepyH)SbBr4 (2-Br) (2cepy = 1-(2-chloroethyl)pyrrolidine), characterized by 1D polar polyanionic chains formed by corner-sharing SbX5 tetragonal pyramid units. Upon photoexcitation at 340 nm, 1-Cl shows broad, yellow phosphorescence emissions stemming from triplet self-trapped excitons, as proved by its long lifetime (6.85 μs) and the temperature dependences of broadband emission. To our knowledge, this should be the first observation on the broadband emissive properties in the 1D hybrid metal halide constructed by MX5 tetragonal pyramid units. Moreover, second harmonic generation measurements show that the nonlinear optical properties of 2-Br (∼3.2 × KDP) are superior to that of 1-Cl (∼1.8 × KDP). Experimental and calculated data indicate that the bandgap of 1-Cl is larger than that of 2-Br and that the polar inorganic moieties determine their band structures. Our work opens up a new way for constructing broadband emission materials with novel polar frameworks.

BACKGROUND: A rolling bearing bush alloy of a feed water pump that is part of a waste heat boiler of an oil refinery has failed. OBJECTIVE: We try to analyze the reasons that caused the working surface of the bearing bush of the water pump to fall off and then give some suggestions to this failure. METHODS: The composition, microstructure, pit, and crack morphology of the bearing bush alloy were analyzed by the X-ray fluorescent analysis, the energy spectrum analysis, the optical microscope and the scanning electron microscope, respectively. RESULTS: The content of Pb in the bearing bush alloy was high, and the Cu content was low. The primary crystal Cu6Sn5 was low, and the crystal of SnSb with low density moved upward and segregated. The above phenomenon reduced the fatigue resistance of the babbitt alloy. The bearing bush was subjected to alternating loads in service, and several small cracks were generated on the bearing bush alloy working surface. The cracks continued to expand and connected with each other. Fatigue pitting occurred on the bearing bush working surface, a large number of pits were formed, and several large alloy blocks fell off. CONCLUSIONS: The Pb content in the failed bearing bush alloy was too high and did not meet the requirements of the Sn-based babbitt alloys in the national standard. At the same time, the primary crystal Cu6Sn5 formed by Cu and Sn was low due to the low Cu content, and the crystal SnSb with a small density moved upward and segregated. The composition of the babbitt alloy, especially the Cu content, should be strictly controlled to ensure the safe and reliable operation of the bearing.

Fluid inhomogeneous distribution affects heat transfer efficiency in the plate-fin heat exchanger (PFHE). In order to improve fluid uniform distribution in the exchanger, the irregular-shaped hole leading flow structure (IHLFS) was proposed for solving fluid inhomogeneous distribution among different layers of PFHE. The inlet distributor with irregular-shaped holes was designed according to different inlet flow velocities aiming at improving fluid uniform distribution. The results on fluid flow and heat transfer characteristics were carried out by the methods of CFD and experimental analysis, and finally, the fluid flow characteristics in inlet section of PFHE with IHLFS were achieved. Comparing with round hole leading flow structure (RHLFS), it can be observed that fluid distribution in PFHE with IHLFS is more uniform than that with round hole, however, the dynamic pressure increases accordingly and finally, increases the ratio of heat transfer and dynamic pressure. The comparison results also demonstrate that the IHLFS can improve fluid distribution, decrease fluid impact in inlet section of PFHE and finally, improve heat transfer enhancement.

Rock dynamic constitutive model plays an important role in understanding dynamic response and addressing rock dynamic problems. Based on elastoplastic mechanics and damage mechanics, a dynamic constitutive model of rock coupled with elastoplastic damage is established. In this model, unified strength theory is taken as the yield criterion; to reflect the different damage evolution law of rocks under tension and pressure conditions, the effective plastic strain and volumetric plastic strain are used to represent the compressive damage variable and the equivalent plastic strain is used to represent the tensile damage variable; the plastic hardening behavior and strain rate effect of rocks are characterized by piecewise function and dynamic increase factor function, respectively; Fortran language and LS-DYNA User-Defined Interface (Umat) are used to numerically implement the constitutive model; the constitutive model is verified by three classical examples of rock uniaxial and triaxial compression tests, rock uniaxial tensile test, and rock ballistic test. The results show that the constitutive model can describe the dynamic and static mechanical behavior of rock comprehensively.

Chamfered inserts have found broader applications in metal cutting process especially in high-performance machining of hard-to-cut materials for their excellent edge resistance and cutting toughness. However, excessive heat generation and resulting high cutting temperature eventually cause severe tool wear and poor surface integrity, which simultaneously limits the optimal selection of machining parameters. In the present study, an analytical thermal–mechanical model is proposed for the prediction of the three-dimensional (3-D) temperature field in cylindrical turning with chamfered round insert based on a modified slip-line field approach. First, an innovative discretization method is introduced in a general 3-D coordinate system to provide a comprehensive demonstration of the irregular cutting geometry and heat generation zones. Then, a plasticity-theory-based slip-line field model is developed and employed to determine the intensities and geometries of every elementary heat sources in Primary Deformation Zones (PDZ), Secondary Deformation Zones (SDZ) and Dead Metal Zones (DMZ). At last, a 3-D analytical model is suggested to calculate the temperature increases caused by the entire heat sources and associated images. The maximum cutting temperature region predicted is found existing upon the chip-tool contact area rather than the tool edge. Moreover, the rationalities of cutting parameters employed are analyzed along with theoretical material removal rates and ensuing maximum cutting temperatures. The results indicate that the cutting conditions with large depth of cut and high cutting speed are more desirable than those with high feed rates. The proposed models are respectively verified through a series of 3-D Finite Element (FE) simulations and dry cutting experiments of Inconel 718 with chamfered round insert. Satisfactory agreement has been reached between the predictions and simulations as well as the measurements, which confirms the correctness and effectiveness of the presented analytical model.

It is desirable to develop highly efficient and sustainable catalytic systems for CO2 photoreduction using efficient heterogeneous photosensitizers (PSs); however, this remains a great challenge. In this study, we doped [Ru(bpy)3]2+ into UiO-metal-organic frameworks (MOFs) to facilitate the separation and reuse of noble metal PS. By simply adjusting the loading amount, a series of heterogeneous photoactive MOFs, namely, UiO-Ru-1, UiO-Ru-2, and UiO-Ru-3, were constructed to act as heterogeneous PSs to drive the efficient CO2 photoreduction under visible-light irradiation. Remarkably, UiO-Ru-2 exhibited the best photosensitizing ability among the prepared MOFs in sensitizing the iron quarterpyridine catalyst (C-1), and the CO yield reached as high as 171 mmol/g with ca. 100% selectivity, which is a record value among all the MOF-based photocatalysts. This photoactive MOF can be recycled and reused three times without any obvious activity loss, signifying its good photochemical stability. Experimental investigations confirmed that the strong visible absorption, long-lived excited state, appropriate redox potential, good photocatalytic stability, and excellent collaboration with C-1 were attributable to the superior catalytic activity. This work highlights an avenue for constructing heterogeneous PSs with excellent recyclability using MOF as the platform for efficient CO2 reduction.

It is of great significance to develop a highly active, durable and inexpensive bifunctional electrocatalyst for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, we report a tungsten-doped nickel phosphide nanosheets based on carbon cloth (W–Ni2P NS/CC) as an efficient bifunctional catalyst through simple hydrothermal and phosphorization for overall water splitting in 1 M KOH. The W–Ni2P NS/CC exhibits excellent electrochemical performance with low overpotentials for HER (η10 = 71 mV, η50 = 160 mV) and OER (η20 = 307 mV, η50 = 382 mV) in 1 M KOH, as well as superior long-term stability. Moreover, W–Ni2P NS/CC as a bifunctional catalyst reveals remarkable activity with a low voltage of 1.55 V to reach a current density of 20 mA cm−2. This work provides a viable bifunctional catalyst for the overall water splitting.

Traditional combination therapy of photodynamic therapy (PDT) and photothermal therapy (PTT) is limited in the field of clinical cancer therapy due to activation by light with separate wavelengths, insufficient O2 supply, antioxidant ability of glutathione (GSH) in tumor cell, and low penetration depth of light. Here, a multifunctional nanoplatform composed of MoO3-x nanosheets, Ag nanocubes, and MnO2 nanoparticles was developed to overcome these drawbacks. For this nanoplatform, hyperthermia and reactive oxygen species (ROS) were simultaneously generated under single 808 nm near-infrared (NIR) light irradiation. Once this nanoplatform accumulated in the tumor region, GSH was depleted by MnO2 and intracellular H2O2 was catalyzed by MnO2 to produce O2 to relieve hypoxia. Ultrasound (US) imaging confirmed in-situ O2 generation. Magnetic resonance (MR) imaging, photoacoustic (PA) imaging, and fluorescence imaging were used to monitor in vivo biodistribution of nanomaterials. This provides a paradigm to rationally design a single NIR laser induced multimodal imaging-guided efficient PDT/PTT cancer strategy.

Hard carbons (HC) derived from biomass material are most promising anodes for lithium-ion batteries (LIBs) because of their cost effectiveness and environmental friendliness. However, the low initial Coulombic efficiency (ICE) of HC anodes reduces the energy density of full cells, which seriously impedes their practical applications. Herein, we demonstrate that the ICE of HC anodes can be significantly improved by modulating the work function of a model HC derived from cotton and deliberately treated to form C-Cl bonds on its surface. By X-ray absorption near-edge structure and density functional theory (DFT) calculation studies, it is verified that the introduction of the C-Cl bond leads to the electron transfer from C to Cl and enhances the work function of the system. In addition, this Cl-doped HC anode can inhibit the reduction of solvent molecules in the electrolyte and reduce the formation of a solid electrolyte interface (SEI) film. Consequently, the ICE is improved from 64.8 to 78.1%. This study provides an effective route to reduce the formation of the SEI film and improve the ICE of hard carbon anodes for LIBs.

In this paper, based on experimental results from sensors implemented in two SOI (Silicon On Insulator) processes offered by MEMSCAP ( $10~\mu \text{m}$ and $25~\mu \text{m}$ ), a comparative study of the implementation of a Pirani-based multifunction sensor has been conducted. The purpose of this study is to choose the most adequate process for the design and implementation of Pirani-based multifunction sensor for both temperature and pressure measurement. Particularly unlike the conventional use of Pirani Vacuum sensor, the Pirani-based sensor is exploited for near and even above atmospheric pressure measurement. The comparison is made in terms of sensor implementation robustness against technological dispersions, its impact on temperature measurement and on pressure measurement under atmospheric condition (1Bar). The optimized design of the multifunction sensor is also investigated through the choice of sensor resistance by way of power consumption, electro-thermal conversion as well as measurement resolution. A design guideline is provided. The experimental results have put into evidence that a better performance is achieved with the $25~\mu \text{m}$ process.

Chronic wound healing, impeded by bacterial infections and drug resistance, poses a threat to global human health. Antibacterial phototherapy is an effective way to fight microbial infection without causing drug resistance. Covalent organic frameworks (COFs) are a class of highly crystalline functional porous carbon-based materials composed of light atoms (e.g., carbon, nitrogen, oxygen, and borane), showing potential applications in the biomedical field. Herein, we constructed porphyrin-based COF nanosheets (TP-Por CON) for synergizing photodynamic and photothermal therapy under red light irradiation (e.g., 635 nm). Moreover, a nitric oxide (NO) donor molecule, BNN6, was encapsulated into the pore volume of the crystalline porous framework structure to moderately release NO triggered by red light irradiation for realizing gaseous therapy. Therefore, we successfully synthesized a novel TP-Por CON@BNN6-integrated heterojunction for thoroughly killing Gram-negative bacteria Escherichia coli and Gram-positive bacteria Staphylococcus aureusin vitro. Our research identified that TP-Por CON@BNN6 has favorable biocompatibility and biodegradability, low phototoxicity, anti-inflammatory properties, and excellent mice wound healing ability in vivo. This study indicates that the TP-Por CON@BNN6-integrated heterojunction with multifunctional properties provides a potential strategy for COF-based gaseous therapy and microorganism-infected chronic wound healing.

Surface machined by high-speed wire electrical discharge machining (HS-WEDM) at super-high thickness (more than 1000 mm) cutting suffers from uneven surface, a major problem that has been investigated in this paper. According to the analysis, as wire frame span increases, the rigidity of the wire electrode decreases, and under the action of discharge explosive force, wire electrode vibration intensifies. As a result, the machining stability inevitably decreases. However, the core problem is whether there is enough working fluid in the slit to dampen and absorb the vibration of the wire electrode so as to ensure the positional stability of the wire electrode. To verify the above point of view: first, the wire guide and gravity take-up with bidirectional tension in the wire feeding system were installed to improve the positional accuracy of the wire electrode; second, to improve the flow of the working fluid into the slit, the slit width was increased by improving the working fluid and a medium carrier with a higher melting point and vaporization point can reduce the vaporization of the working fluid in the slit as much as possible. The experiment showed that the outlet flow of the improved working fluid is 56.72% higher than that of the original working fluid when cutting a 750 mm thick workpiece, which increases the damping and vibration absorption effect of the working fluid on the wire electrode in the long and narrow gap. After the above measures were implemented, super-high thickness cutting can be carried out continuously and steadily, the surface evenness was significantly improved, and the workpiece with a thickness of 2000 mm was cut successfully.

To study the internal mechanism of the metal-electric explosion process, it is necessary to obtain internal information regarding the flow field by performing transmission imaging of the electric explosion plasma. In this study, a laser plasma X-ray source is used as the transient X-ray source. Flyer dynamic X-ray imaging technology of laser plasma X-ray sources is realized by designing and developing flyer-driving devices, laser plasma X-ray devices, and timing synchronization modules. This technology has the advantages of producing images having high-brightness and high temporal and spatial resolutions, and it can adapt to the transmission imaging of high-speed micro flyers and their accompanying plasma. The experimental results show that a clear image of a high-speed flyer and the internal state information of the plasma can be obtained by using this technology. The spatial resolution is 8 μm/pixel, and the temporal resolution is 1 ns. This study presents an experimental method for further studies on the evolution process of plasma and flyers.

By connecting tercarbazole (3Cz) and triphenyltriazine (TRz) units with a diphenyl ether group, we designed and synthesized a new donor-spacer-acceptor structure molecule 9′-(4-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenoxy) phenyl)-9′H-9,3′:6′,9″-tercarbazole (3Cz-o-TRz) as the multifunctional component of exciplex emitters. As expected, the intermolecular charge-transfer transition is dominant for 3Cz-o-TRz because of the space-enough and conjugation-forbidden linkage of the diphenyl ether group, increasing the intrinsic characteristics of the 3Cz and TRz moieties in its single-molecule state. Accordingly, three common electron acceptors (4,6-bis(3,5-di(pyridin-3-yl)phenyl)-2-methylpyrimidine (B3PyMPm), 4,6-bis(3,5-di(pyridin-4-yl)phenyl)-2-methylpyrimidine (B4PyMPm), and (1,3,5-triazine-2,4,6-triyl) tris(benzene-3,1-diyl)tris(diphenylphosphineoxide) (POT2T)) and three common electron donors (4,4′-(cyclohexane-1,1-diyl)bis(N, N-di-p-tolylaniline) (TAPC), tris(4-(10H-phenoxazin-10-yl)phenyl)amine (TPA-PXZ), and N1-phenyl-N4, N4-bis(4-(phenyl(m-tolyl)amino)phenyl)-N1-(m-tolyl)benzene-1,4-diamine (m-MTDATA)) were chosen to construct six exciplex emitters with 3Cz-o-TRz. In the organic light-emitting diodes (OLEDs), the emission spectra of these exciplex emitters could be gradually modulated from 510 to 590 nm. In addition, TAPC:3Cz-o-TRz- and 3Cz-o-TRz:PO-T2T-based OLEDs achieved desirable performance with maximum external quantum efficiencies (EQEs) around 12%. Moreover, a simple tandem OLED containing TAPC:3Cz-o-TRz and 3Cz-o-TRz:PO-T2T emitters realized optimal performance with an ultralow turn-on voltage of 2.4 V and a maximum EQE of 14.1%. These results indicate the great potential of the donor-spacer-acceptor structure compounds in developing exciplex emitters.

The discovery of narrow-band luminescent materials remains an immense challenge to optimize the performance of white light-emitting diodes (LEDs). So far, the zero-dimensional (0D) Mn2+-based halid...

This study focuses on mechanism on thermal residual stress formation in fibre reinforced polymer (FRP) composites. It proposed that the threshold temperature for thermal residual stress formation during the curing process of FRP composites is the gel temperature (Tgel) of resin matrix. An equation is used to characterise the relationship between thermal deformation and temperature. A model of the basic principle for the micro-scale thermal residual stress of FRP composite is established and the calculation formula is derived. The mechanism is verified by testing on carbon fibre reinforced polymer (CFRP) composites via RTM process and finite element analysis (FEA), which calculates cure shrinkage deformation of FRP specimen theoretically. The shrinkage deformation results from RTM specimens coincide with those from the FEA simulation.

In this paper, we used cyclic voltammetry method to prepare manganese dioxide with different scanning rates of voltage on a three-dimensional porous nickel foam substrate. We systematically studied the influence of the scanning rate of electrodeposition on the morphology, structure, and electrochemical performance of the sample. According to the electrochemical performance, we found the optimal electrodeposition parameters, and the electrode prepared under this condition has a high specific capacitance (458 F g−1 and 286 F g−1 at the current density of 1 A g−1 and 10 A g−1) and low impedance.

Proton-conductive materials have attracted increasing attention because of their broad explorations in chemical sensors, water electrolysis, fuel cells, and biological systems. Especially, metal-organic frameworks (MOFs) have been demonstrated to be extremely promising candidates as proton-exchange membrane (PEM) fuel cells. Compared with other configurations, MOFs with one-dimensional (1D) channels have the characteristics of enhancing the host-guest interaction and promoting the anisotropic motion of proton carriers in restricted volume, which are beneficial for acquiring rich proton sources and forming successive hydrogen bonds to improve proton conductivity. We are endeavored to screen and find a helical three-dimensional (3D) framework InOF-1, namely, [In2(OH)2(BPTC)]·6H2O (BPTC4- = 3,3',5,5'-biphenyl tetracarboxylate), as a typical 1D-channel MOF, which is pristinely grafted with spirally distributed -OH groups on the channel surface. Accompanied by an aliovalent substitution Ni(II) for In(III), isostructural NiOF-1 ([Ni2(BPTC)(HCOOH)2]·3H2O) is successfully prepared and massive formic acids are anchored at interior walls, which are interacted with adsorbed water molecules via the formation of stronger O-H···O bonds. This interaction between host-guest molecules and dynamics of lattice water has already led to a remarkable conductivity of InOF-1 (σ = 7.86 × 10-3 S/cm at 328 K under 95% RH). The synergistic effect of the acidic-modified nanowall, contracted volume, and enhanced adsorption of water molecules in the NiOF-1 channel contributes to a high conductivity value of 3.41 × 10-2 S/cm (at 328 K under 95% RH). Moreover, the proton conduction mechanism is further visually presented by molecular dynamic (MD) simulation. In contrast to InOF-1, aliovalent-substituted and acidic-modified NiOF-1 has a stronger host-guest interaction and more abundant hydrogen-bond networks, resulting in shorter proton migration distances and more frequent proton hopping, in agreement with the experimental results.

Graphene oxide (GO) is a novel nano-carbon material with excellent mechanical properties. It can be used in cement-based materials to induce cement hydration and enhance the strength and the toughn...

The introduction of chirality into organic-inorganic hybrid perovskites (OIHPs) is expected to achieve excellent photoelectric and nonlinear materials related to circular dichroism. Owing to the existence of asymmetric center and intrinsic chirality in the chiral OIHPs, the different efficiencies of second harmonic generation (SHG) signal occurs when the circularly polarized light (CPL) with different phases passes through the chiral crystal, which is defined as second harmonic generation circular dichroism (SHG-CD). Here, the SHG-CD effect is developed in bulk single crystals of chiral one-dimensional (1D) [(R/S)-3-aminopiperidine]PbI4 . It is the first time that CPL is distinguished using chirality-dependent SHG-CD effect in OIHPs bulk single crystals. Such SHG-CD technology extends the detection range to near infrared region (NIR). In this way, the anisotropy factor (gSHG-CD ) through SHG-CD signal is as high as 0.21.

The ground pressure distributes significant variation in underground mining near fault. Fault reactivation is an important factor to induce the rock burst. Therefore, characterizing geological settings in mining areas by the geological information can improve the accuracy of simulation. To investigate the characteristic of mining stress evolution and reactivation of the F16 reverse fault during the retreat Mining-Induced s in Yima coalfield, a three-dimensional digital elevation model based on GIS platform was applied. The 3D geological model includes three working faces, and F16 fault was constructed by AutoCAD software. Then, the 3D geological model was imported into the FLAC3D code to simulate the potential of mining-induced fault reactivation. The simulation results illustrate that the footwall of F16 fault is a high stress concentration area. Affected by F16 fault and the huge thick gravel rock in the roof, the coal seam near the fault accumulates a large amount of elastic strain energy, which increases the potential of rock burst hazards in the process of mining.

The torsional vibration is a technical problem during the rolling process, which seriously affects rolling stability and production efficiency. In order to study the influence of axis deviation of the rolling mill transmission system on torsional vibration, a reasonable dynamic model can be established to explore its dynamic characteristics. In this paper, considering the periodic excitation caused by the axis deviations and the torsional torque change under the torsional vibration, the nonlinear dynamic model of the transmission system was established. The simulation results show the energy input to the main transmission system approximately periodically through obtaining the drive energy of the rolling mill motor by the equivalent eccentric mass. The dynamic change of tension and friction moment of the strip is caused by the torsional vibration of the transmission system, which leads to an unstable energy conversion process in the rolling interface. Through the monitoring experiment data by taking the 7-stand tandem hot rolling mill of Chengde Steel Co. for example, the theory reliability was further verified. All these research results are significant to solving the torsional vibration problem of rolling mill drive system with axis deviations and provide references for the operation in the strip production process.

The Curie temperature of electron-doped Sr2FeMoO6 can be optimized significantly due to the band-filling effect, but accompanying an almost absent low-field magnetoresistance (LFMR), which is unfavorable to applications in the magnetoresistive devices operated at room-temperature. Our previous works confirmed that, a remarkable enhanced LFMR was observed in Sr2FeMoO6 by modifying the grain boundary with insulating organic small molecules (glycerin, CH2OHCHOHCH2OH). However, in this work, modifying the grain boundary strength of the La0.5Sr1.5FeMoO6 with the insulating organic macromolecules (oleic acid, CH3(CH2)7CH=CH(CH2)7COOH) or small molecules (glycerin), both of them have negligible functions on the magnetoresistance behavior in La0.5Sr1.5FeMoO6. Contrary to the glycerin-modified Sr2FeMoO6, Sr2FeMoO6/oleic acid composites don’t exhibit an obviously increased magnetoresistance property. Based on the above experimental results and the related works, it is proposed that, maintaining high spin polarization of the carriers at the Fermi level and improving the tunneling process across the grain boundary by using the suitable organic materials are decisive factors for optimizing the magnetoresistance behavior in the similar electron-doped double perovskites.