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A novel method for bamboo scrimber strengthening timber beams with anchorage structures was proposed. Bamboo scrimber was adhered to the bottom of the timber beam and anchored with carbon fiber-reinforced polymers (CFRPs) or wooden pins. Through the bending tests of eight reinforced beams and two control beams, the effects of different forms of anchorage and thicknesses of bamboo scrimber on the strengthening effect of timber beams were studied. The failure characteristics of the timber beams were observed, and the ultimate load, stiffness and ductility were analyzed. The results show that the failure modes of timber beams can be divided into bending failure and bending-shear failure and that the timber beams exhibit obvious signs of ductile deformation before failure. The ultimate bearing capacity of the reinforced beams increased by approximately 20%–70%, and the cross-sectional stiffness at the serviceability limit state increased by approximately 40%–160%. The test results confirm that CFRPs and wooden pins can firmly adhere to the timber beam and bamboo scrimber, so the bamboo scrimber strengthening timber beams with anchorage structures can substantially increase the ultimate bearing capacity and stiffness and improve the ductility of the member.

Silicon (Si) material, with high specific capacity (4200 mAh/g) and low discharge voltage, is considered as one of the most ideal, promising, and alternative anode materials in next-generation lithium-ion battery (LIBs). In order to resolve the internal drawbacks of Si and reduce the process cost, the Si recycled from the kerf waste of photovoltaic industry was used as raw material. A silane-coupling agent 3–2 (2-sminoethylamino) propyltrimethoxysilane (DAMO) and a binder (PAA) was used to prepare Si@DAMO composite material with cross-linked net structure. Then, the polyvinyl pyrrolidone (PVP) containing N element was coated on the Si@DAMO. After carbonization, the C/Si@DAMO composite material with cross-linked net structure was obtained. The as-prepared C/Si@DAMO anode delivered an initial capacity of around 2841.6 mAh/g, and it remained a reversible capacity of 2066.7 mAh/g after 200 cycles at the current density of 0.1 C. At the rate testing from 0.1 to 1 C, the discharge capacities were 2593.39 mAh/g, 2362.95 mAh/g, 2082.08 mAh/g, 1882.44 mAh/g, 1704.57 mAh/g, and 1545.32 mAh/g, respectively. It retained 2084.88 mAh/g when back to 0.1 C charge rate after 60 cycles. Therefore, it suggests that the as-prepared C/Si@DAMO is a potential anode material for LIBs.

In this review, the present status of nanosilver sintering is adapted in detail. This review shows the current scholarly exploration and achievements in this field through the two aspects of manufacturing and reliability. The preparation of nanosilver particles, organic coating and sintering methods, microstructure and failure modules of sintered nanosilver layers are described in detail. Finally, prospects and dilemmas of nanosilver sintering technology as a connection material for semiconductor devices and the directions of future extensions are discussed.

Silicon is widely used as anode for lithium-ion batteries (LIBs). However, its application is limited due to some problems such as large volume expansion. In this work, silicon waste from wafer slicing via diamond wire saw technology in photovoltaic industry is used as raw materials. A submicron core-shell structure Si@C intertwined with CNWs and graphene nanosheet, is prepared as anode for LIBs by hydrothermal process. The anode retains a specific capacity of 2514.8 mAh g−1 with capacity retention of 75.8% after 360 cycles under a current of 0.1 C and 1548.9 mAh g−1 after 1000 cycles under 0.2 C. In addition, it maintains 1596.9 mAh g−1 (1.0 C), 925.3 mAh g−1 (2.0 C) after several rate testing of 0.1 C to 2.0 C. A COMSOL Multiphysics and MD simulation are performed to examine the lithiation-induced volume expansion of silicon. The results demonstrate that, the lamellar micron silicon can achieve a stable lithium intercalating capacity larger than 2100 mAh g−1, which agrees well with our experimental results. It is demonstrated that the submicron Si from the kerf waste in the photovoltaic slicing process via diamond wire saw technology are available as direct raw materials for high performance anode of LIBs.

Utilizing granulated blast furnace slag (GBFS), coal fly ash (FA), and furfural residue incineration ash (FRIA) as pozzolanic materials, then activated with calcium carbide residue (CCR) respectively to prepare all-solid-waste alkali activated binders (ASW binders). The laboratory tests were performed to research the effects of pozzolanic materials with different reactivity on the macro- and micro- characteristics of solidified marine soft soil. Results show that the mechanical properties and alkali-activation process of ASW binders solidified soil was determined mainly by the reactivity of pozzolanic materials, the higher reactivity of the pozzolanic materials in ASW binders couldn’t change the main hydration products, however, it would accelerate the hydrate reaction. The degree of hydrate reaction increased, the microstructure became denser with the increase of the reactivity of the pozzolanic materials in ASW binders solidified soil, on the macro- side, the strength and deformation modulus of the solidified soil increased, meanwhile, the brittleness of the solidified soil will be more obvious during the deformation resistance process. ASW binders (CCR:GBFS=1:1) solidified soil could reach the strength of cemented soil under the same conditions.

The embedding of steel bars is proposed to enhance the load-bearing performance of bamboo beams. Based on laboratory tests, the bending behavior of bamboo beams reinforced with steel bars or prestressed steel bars was analyzed using finite element software. Comparing the finite element simulation results with those measured in tests, it can be found that the load–displacement curves coincide with each other, and the strain development processes in the mid-span are basically the same. The prediction by the finite element simulation has good accuracy. The embedding of steel bars and prestressed steel bars can effectively improve the ultimate bearing capacity (up to 27.0%), bending stiffness at the serviceability limit state (up to 42.61%), ductility (up to 22.9%), and material utilization efficiency (up to 34.1%) for the bamboo beams. The embedding of steel bars makes the bamboo in the compression zone of the beams develop with higher efficiency, and applying the prestress for steel bars can produce reverse bending deformation and reduce the actual deflection for the reinforced bamboo beam under service load. Under the same reinforcement ratio, the prestress level has a relatively small influence on the ultimate bearing capacity (up to 4.5%) and stiffness (up to 4.5%) of the reinforced beam.

A novel bamboo-concrete composite structure with threaded reinforcement connections is presented. Experimental investigations on the shear behavior of the connectors and the flexural performance of the bamboo-concrete composite beams were carried out. The results indicate that the load-slip behavior of the shear connection with threaded reinforcement exhibits good ductility and that its failure mode is ductile failure. The threaded reinforcement provides an efficient connection before the initial shear failure. The load-displacement curves of the bamboo-concrete composite beams are close to those of the full composite structure, and the midspan displacement is greatly reduced under the same load compared with that of the contrast bamboo beams. The loads PL/250and PL/300, corresponding to the midspan deflections of L/250 and L/300 ( L is the span of the beams) of the composite beams, increase by averages of 3.36 times and 3.71 times, respectively, compared to those of the contrast bamboo beams. The load-bearing performance of the beams in the service state is greatly improved. Based on the equivalent cross-sectional stiffness calculated using the γ-method with a reduction of 0.80, the calculated results of the displacement are in good agreement with the test results.

Supported metal nanoclusters consisting of several dozen atoms are highly attractive for heterogeneous catalysis with unique catalytic properties. However, the metal nanocluster catalysts face the challenges of thermal sintering and consequent deactivation owing to the loss of metal surface areas particularly in the applications of high-temperature reactions. Here, we report that sulfur—a documented poison reagent for metal catalysts—when doped in a carbon matrix can stabilize ~1 nanometer metal nanoclusters (Pt, Ru, Rh, Os, and Ir) at high temperatures up to 700 °C. We find that the enhanced adhesion strength between metal nanoclusters and the sulfur-doped carbon support, which arises from the interfacial metal-sulfur bonding, greatly retards both metal atom diffusion and nanocluster migration. In catalyzing propane dehydrogenation at 550 °C, the sulfur-doped carbon supported Pt nanocluster catalyst with interfacial electronic effects exhibits higher selectivity to propene as well as more stable durability than sulfur-free carbon supported catalysts., The sulfur is a documented poison reagent for metal catalysts. Here the authors show when doped in a carbon matrix, sulfur can enhance the adhesion strength and eventually suppress the metal sintering, which improve the performance of propane dehydrogenation by strong chemical/electronic interactions.

Random trapping and detrapping of charged carriers in the vicinity of gate oxide/Si interface has for long been considered as the dominant noise source in Si nanowire (SiNW) FET-based biochemical sensors. Here we extend our previous work presenting a Schottky junction tri-gate SiNWFETs (SJGFET) fabricated on a bonded silicon-on-insulator (SOI) substrate, aiming for ultra-low device noise generation. The SJGFET exhibits near-ideal gate coupling efficiency with a subthreshold swing of ~66 mV/dec. Its gate-referred voltage noise, $S_{\text {vg}}$ , are ${1.2}\times {10}^{-{10}}$ and ${1.1}\times {10}^{-{11}}\,\,\text {V}^{{2}}\,\,\mu \text{m}^{{2}}$ /Hz at 1 and 10 Hz, respectively. These $S_{\text {vg}}$ values are significantly lower than that of previously reported FET-based sensors. More importantly, $S_{\text {vg}}$ of the SJGFET are below the reported voltage noise generated by the oxide/electrolyte sensing interface. Using our SJGFET as the signal transducer can greatly relieve the concern of the adverse effect from the intrinsic device noise in biochemical sensing applications.

Analyzing the assembly patterns of multicomponent gelators is important for understanding their assembly rules and precisely manipulating their molecular structure to form a tailored multifunctional supramolecular gel. But the fast in situ recognition technology to infer whether the assembly pattern is a self-sorting or co-assembled system is lacking. For developing a widely applicable stable and sensitive fluorescent probe to infer assembly patterns, we design and synthesize the multiple peripheral functional group tetraphenylethene (TPE) modified well-defined cubic core polyhedral oligomeric silsesquioxane (POSS) three-dimensional (3D) dendrimer. POSS-TPE can form a thermally stable self-assembly structure after being incubated in a wide temperature range, and the resultant special thermally stable photoluminescence (PL) intensity provides a novel possibility of fluorescent probe. Then, POSS-TPE sensitively catches the mechanical stress changes of the confined space provided by the gel networks and infers the assembly patterns by comparing the mechanical stress change laws of a self-sorting or co-assembled system. So, the application of fluorescent probe in assembly fields is enlarged in this research. In the future, this widely applicable fluorescent probe will be helpful to develop supramolecular assembly materials consisting of multicomponent gels.

In this review, present status of laser welding/brazing (LWB) of aluminum alloy to steel is adopted in detail. This review shows the current scholarly exploration and achievements in this field through the three aspects of the process, microstructure of intermetallic reaction layer, and mechanical properties. From the selection of laser source, temperature control, and filler metal selection, the technological factors of laser welding applied to Fe/Al dissimilar metal bonding are discussed. We presented the relationship between the microstructure and mechanical properties of the intermetallic reaction layer in the Fe/Al joint by laser welding. To sum up, laser welding/brazing has a broad application prospect in Fe/Al dissimilar metal bonding.

As the problem of electromagnetic wave pollution is becoming more and more serious in our daily life, it is urgent to develop a kind of electromagnetic interference (EMI) shielding materials with high-strength and high absorptivity to meet the demand of industrial application. In this study, a facile method is developed to prepare EMI shielding composites with both powerful absorbing and robust mechanical properties by impregnating the suspensions of graphite nanoplatelets (GNP) and polyacrylate expandable foam particles (PEFP) into the porous glass fiber mat reinforced thermoplastics (GMT), and then hot forming and pressing, the thickness of GMT/PEFP/GNP composites is 2 mm. GNP not only acted as an efficient conductive pathway in the GMT/PEFP/GNP composites matrix, but also formed a conductive cell structure with the foamed PEFP, which increased the electromagnetic waves absorption. The total shielding efficiency (SET) of the GMT/PEFP/GNP-4.0 wt% composite is up to 33.8 dB at 11 GHz, and the power coefficient of reflectivity is 0.71, which is lower 17% than that of GMT/GNP composites without the cell structure constructed by PEFP in the matrix. Furthermore, the melting of polypropylene (PP) in the mats act as the interface adhesive for glass fiber (GF) and GNP, so the tensile strength is enhanced up to 22.8 MPa for the GMT/PEFP/GNP-4.0 wt% composites with lightweight, due to the formation of cell structure constructed by the PEFP. Therefore, this paper provides a simple method to prepare lightweight and high-strength GMT/PEFP/GNP composites for EMI shielding, which is of great significance for industrial application.

Recently, mainstream silicon (Si)-based materials and complementary metal oxide semiconductor (CMOS) technology have been used in developing extremely tiny sized (of a few nanometers) devices. However, with the reduction of transistor characteristic dimensions, many new challenges such as the short channel effect and high heat dissipation problems have emerged. Two-dimensional transition metal dichalcogenides (2D TMDs) are deemed the most promising semiconductor materials to conquer the challenge of the short channel effect owing to their excellent properties, including high mobility and atomic thickness. Nevertheless, Fermi-level pinning (FLP) occurs when TMDs are in direct contact with metal electrodes, which causes an uncontrollable Schottky barrier and a high contact resistance, limiting the device performance. In this review, we summarize the recent progress on how to circumvent FLP between 2D TMDs semiconductors and metals. Firstly, the related concepts, aiming to get an in-depth understanding of FLP are introduced. Secondly, we discuss the factors contributing to FLP in detail and the strategies of Fermi-level depinning according to these factors. Finally, we present a summary and outlook, which will provide a guideline for suppressing FLP in the process of fabricating high-performance 2D TMD devices.

In this work, the influence of the acceptor-type trap on the threshold voltage and short-channel effect is analyzed and modeled for the short-channel GaN MOS-HEMT. Particularly, the analysis and modeling are carried out with the dependences of the traps’ ionization condition on the gate voltage and drain voltage considered. From the calculated results based on the proposed threshold voltage model, it is found that both the interface acceptor-type trap and buffer acceptor-type trap play a vital role in the threshold voltage reduction for the short-channel AlGaN/GaN MOS-HEMT, due to the acceptor-type trap’s detrapping effect induced by the drain voltage. The calculated results are well supported by the numerical simulation, which verified the correctness and accuracy of the presented model.

Through silicon via (TSV) has become one of the key emerging trends of three-dimensional (3D) packages, as it can realize vertically interconnect between stacked-dies. Due to large mismatch in thermal expansion coefficients (CTE) between the copper via and the silicon, significant mechanical stresses are induced at the interfaces when TSV structure is subjected to thermal stresses, which would greatly affect the reliability and electrical performance of TSV 3D device. In this paper, the relationship between the state of stresses and failure of TSV had been explored by combining finite element model simulation (FEM) and failure physical analysis. The position of the maximum stress of the TSV structure was obtained by FEM analysis. The relationship of stress and displacement change with temperature was also studied. And a thermal cycling experiment was conducted to validate the simulation results. Physical failure analysis after thermal cycling experiment was used to verify the degradation mechanism predicted by thermo-mechanical simulation.

Heterointerfaces coupling complex oxides exhibit coexisting functional properties such as magnetism, superconductivity, and ferroelectricity, often absent in their individual constituent. SrTiO3 (STO), a canonical band insulator, is an active constituent of such heterointerfaces. Temperature-, strain-, or mechanical stress-induced ferroelastic transition leads to the formation of narrow domains and domain walls in STO. Such ferroelastic domain walls have been studied using imaging or transport techniques and, often, the findings are influenced by the choice and interaction of the electrodes with STO. In this work, we use graphene as a unique platform to unveil the movement of oxygen vacancies and ferroelastic domain walls near the STO surface by studying the temperature and gate bias dependence of charge transport in graphene. By sweeping the back gate voltage, we observe antihysteresis in graphene typically observed in conventional ferroelectric oxides. Interestingly, we find features in antihysteresis that are related to the movement of domain walls and of oxygen vacancies in STO. We ascertain this by analyzing the time dependence of the graphene square resistance at different temperatures and gate bias. Density functional calculations estimate the surface polarization and formation energies of layer-dependent oxygen vacancies in STO. This corroborates quantitatively with the activation energies determined from the temperature dependence of the graphene square resistance. Introduction of a hexagonal boron nitride (hBN) layer, of varying thicknesses, between graphene and STO leads to a gradual disappearance of the observed features, implying the influence of the domain walls onto the potential landscape in graphene.

With the rapid development of the machinery industry, bearing materials with better tribological properties are demanded. Al alloys containing Erbium (Er) and Zirconium (Zr) have better comprehensive performance, whose tribological properties have hardly been reported before. In this work, dry sliding wear tests were performed on the Al–Sn and Al–Sn–Er–Zr alloys in two different annealing states to study the effect of trace Er, Zr on the tribological properties of the Al–Sn alloys. The Al–Sn–Er–Zr alloys showed better wear resistance than the Al–Sn alloys, which was mainly due to the higher hardness and strength of the Al–Sn–Er–Zr alloys. The wear losses of the alloys annealed at 375 °C for 100 h at the load of 70 N were significantly lower than those of the alloys annealed at 300 °C for 4 h. The wear coefficient K of the alloys annealed at 375 °C for 100 h decreased with the increasing load. The Al–Sn–Er–Zr alloys showed smoother worn surfaces than the Al–Sn alloys. With the load increasing, the wear mechanism changed from abrasive wear, mild adhesive wear and slight delamination wear to severe adhesive wear and delamination wear. The wear scars of different samples under the same load were similar, indicating that the addition of trace Er, Zr and annealing process did not change the wear mechanism. All samples experienced cracks and voids in the tribolayers. And oxygen accumulated in these defects. Most wear debris were lamellar, which was related to the adhesive wear and consist with the delamination theory.

The multi-modal imaging contrast agent has been attracted an increased interest to the tumor detecting and diagnosis in these recent years since the multi-modal imaging technology combines the adva...

In this study, iron–copper–nitrogen macrocyclic complexes prepared with Vulcan XC-72 carbon (Fe–Cu–N4/C) were used as trifunctional electrocatalysts to promote the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) of Zn–air batteries and overall water splitting. The electrocatalytic activities of Fe–Cu–N4 with different calcination temperatures and Fe and Cu contact ratios were carefully studied. Among the macrocyclic complexes, Fe–Cu–N4 prepared with a Fe:Cu mole ratio of 1:1 at 900 °C calcination temperature and mixed with carbon (Fe–Cu–N4 900/C) exhibited good electrochemical characteristics. As an air cathode of a self-assembled rechargeable Zn–air battery, Fe–Cu–N4 900/C showed good performance characteristics, such as a maximum power density of 84.75 mW cm−2, a specific capacity of 619.6 mAh g−1, and a specific energy density of 734.0 Wh kg−1 at a current density of 10 mA cm−2. Furthermore, Fe–Cu–N4 900/C electrocatalysts were constructed as a catalytic cathode and anode couple to explore the practical overall water splitting competency.

Lanthanum-cerium-tantalum-oxide (LCT) thermal barrier coatings (TBCs) were prepared by air plasma spraying at three different spray powers. Then, the effects of spray power on the microstructure, composition, thermophysical properties, mechanical performances, and thermal cycling behaviors of the coatings were investigated in detail. The results indicated that when the spray power was increased from 30 kW to 42 kW in 6 kW steps, the coating became denser, the La/(Ce + Ta) ratio of the as-sprayed coating first increased slowly and then sharply, and the thermal conductivity and thermal expansion coefficient of the coating gradually increased and decreased, respectively. In addition, the Vickers hardness, Young's modulus, and fracture toughness of the coating first increased and then decreased. The spray power had a significant impact on the thermal cycling performance of LCT coating. The LCT coating prepared at low power showed better thermal shock resistance. The thermal expansion mismatch stress and the low fracture toughness of a ceramic top coat are the main reasons for the premature failure of the TBCs.

Safely and highly selective acetylene (C2H2) capture is a great challenge, because of its highly explosive nature, as well as its nearly similar molecule size and boiling point toward the main impurity of carbon dioxide (CO2). Adsorption separation has shown a promising future. Herein, a new nanoporous coordination polymer (PCP) adsorbent with fixed and free Cu ions (termed NTU-66-Cu) was prepared through post-synthetic approach via cation exchanging from the pristine NTU-66, an anionic framework with new 3, 4, 6-c topology and two kinds of cages. The NTU-66-Cu shows significantly improved C2H2/CO2 selectivity from 6 to 32 (v/v: 1/1) or 4 to 42 (v/v: 1/4) at low pressure under 298 K, along with enhanced C2H2 capacity (from 89.22 to 111.53 cm3·g−1). More importantly, this observation was further validated by density functional theory (DFT) calculations and breakthrough experiments under continuous and dynamic conditions. Further, the excellent chemical stability enables this adsorbent to achieve recycle C2H2/CO2 separation without loss of C2H2 capacity.

Layer-structured black phosphorus (BP) demonstrating high specific capacity has been viewed as a very promising anode material for future high-energy-density Li-ion batteries (LIBs). However, its practical application is hindered by large volume change of BP and poor mechanical stability of BP anodes by traditional slurry casting technology. Here, a free-standing flexible anode composed of BP nanosheets and nanocellulose (NC) nanowires is fabricated via a facile vacuum-assisted filtration approach. The constructed free-standing BP@NC composite anode offers three-dimensional (3D) mixed-conducting network for Li+/e- transports. The substrate of NC film has a certain flexibility up to 10.2% elongation that can restrain the volume change of BP and electrode during operation. In addition, molecular dynamic (MD) simulation and density function theory (DFT) show the greatly enhanced Li+ diffusion in BP@NC composite where the Li ions receive less repulsive force at the interface of BP interlayer and nanocellulose. Benefiting from above multifunction of nanocellulose, the BP@NC composite exhibits high capacities of 1020.1 mAh g-1 at 0.1 A g-1 after 230 cycles and 994.4 mAh g-1 at 0.2 A g-1 after 400 cycles, corresponding to high capacity retentions of 87.1% and 84.9%, respectively. Our results provide a low-cost and effective strategy to develop advanced electrodes for next-generation rechargeable batteries.

Conventional homojunction bipolar junction transistors (BJTs) are not suitable for cryogenic operation due to heavy doping-induced emitter band-gap narrowing and strong degradation in current gain ( $\beta $ ) at low temperature. In this letter, we show that, on lateral version of the BJTs (LBJTs) fabricated on silicon-on-insulator (SOI) substrate, such $\beta $ degradation can be mitigated by applying a substrate bias ( ${V}_{sub}$ ), and a $\beta $ over unity is achieved in a base current ( ${I}_{B}$ ) range over 5 orders of magnitudes at 4.2 K, with a peak $\beta \sim 100$ demonstrated. The $\beta $ improvement is explained by the enhanced electron tunneling through base region as a result of base barrier lowering and thinning by a positive ${V}_{sub}$ , which leads to dramatic increase of collector current ( ${I}_{C}$ ) while ${I}_{B}$ is negligibly affected.

The swelling and drying behavior of a gelatin-glycerol-water hydrogel are examined experimentally for different compositions and different environmental conditions. Significant asymmetry in the swelling and drying kinetics is observed from these measurements. The early time measurements are interpreted first within the context of a linear poroelastic theory, but a fully nonlinear Flory-Rehner theory is required in order to capture the long time behavior. Comparison of the experimental measurements with simulations based on both the linear and nonlinear constitutive models yields a consistent calibration of the material parameters of the models.

Objectives Zirconia with 3 mol% yttria (3Y‐TZP) has been used for dental crowns and bridges due to its excellent mechanical behavior. Performing fracture toughness testing on this nanograin material, however, can be a challenge. For reliable results, fracture toughness testing requires an extremely sharp notch in the test specimen that closely approximates a very sharp crack. This study was to investigate an alternative method to produce nanometer‐sized notches, which are less than the average grain size of 3Y‐TZP, during the preparation of single‐edge V‐notched beam specimens and report the resulting fracture toughness value. Methods We present a method using focused ion beam (FIB) milling to fabricate nanometer‐sized notches in 3Y‐TZP. The notch tip is

In this work, the authors demonstrate the control of quality factor (Q‐factor) is laterally coupled vertical cavities. A 3 μm‐side‐length square cavity directly connected to a 1.5 μm‐width, 10 μm‐length Fabry–Perot (FP) cavity has been fabricated and measured. Dynamic tuning of the Q‐factor has been successfully observed by bringing the square cavity and FP cavity into resonance. The vertical‐cavity‐based Q‐factor control scheme provides a new choice for the modulation of light and holds potentials for applications associated with optical information processing.

Background Shear wave elastography is a promising method to diagnose early musculoskeletal lesions. We aimed to explore the feasible depth and acceptable precompression applied by probe and couplant for soft tissues in the present system. Methods Ex-vivo muscles were evaluated at depths of 0.5-6 cm by 3 operators, using 1-5 mm couplant thickness and 0-3.0 kPa probe pressure. We compared the shear wave speed (SWS) and used intraclass correlation coefficients to assess reproducibility. In vivo skin and subcutaneous superficial fascia from volunteers were tested at depths ranging from 0.1-0.5 cm with 1-20 mm couplant thickness. Results The SWS of ex-vivo muscles varied and increased with depth, and could not be acquired at 6 cm because the shear wave failed to be detected. Furthermore, while the SWS of ex-vivo muscles were not affected by the couplant thickness, it was affected by probe pressure. Most cases demonstrated a satisfactory agreement degree of the intraoperator reproducibility (ICC, 0.81-0.95) and a substantial interoperator reproducibility (ICC >0.60). Inter- and intra-operator reproducibility was better at a depth of 0.5-4 cm than at 5 cm. In the in vivo study, when tissues within a 0.2 cm depth were evaluated, the SWS that was acquired using a couplant thickness of >10 mm was different from that acquired using other thicknesses. Conclusions The SWS acquired at a depth of ≤3 cm with a suitable amount of couplant is recommended.

The conversion of carbon dioxide into valuable organic compounds is a highly promising approach to address the energy issues and environmental problems (e.g., global warming). Herein, we presents a facile and efficient method to prepare highly dense and well-dispersed SnO2 nanocrystals on 1D N-doped carbon nanowires as advanced catalysts for the efficient electroreduction of CO2 to formate. The ultrasmall SnO2 coated on the N-doped carbon nanowires (SnO2@N-CNW) has been synthesized via the simple hydrothermal treatment coupled with a pyrolysis process. The unique structure enables to expose the active tin oxide and also provides the facile pathways for rapid transfer of electron and electrolyte along with the highly porous carbon foam composed with interconnected carbon nanowires. Therefore, SnO2@N-CNW electrocatalyst exhibits good durability and high selectivity for formate formation with a Faradaic efficiency of ca. 90%. This work demonstrates a simple method to rationally design high-dense tin oxide nanocrystals on the conductive carbon support as advanced catalysts for CO2 electroreduction.

Exploration of cost-effective and highly durable carbon-based multifunctional electrocatalysts for energy conversion and storage devices (e.g., metal-air batteries) is of critical significance. Herein, we present a unique worm-like structure of hierarchically porous nitrogen-doped graphene (N-rGO) embedded with cobalt nitride (Co5.47N) nanoparticles (named as Co5.47N@N-rGO) by tannic acid assisted nitridation method for Zn-air batteries and overall water splitting. Benefiting from the unique worm-like structure to expose more active sites and the synergy advantages of a close contact between Co5.47N nanoparticles and the N-rGO sheets, the Co5.47N@N-rGO exhibits efficient bifunctional catalytic activities toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Notably, Zn-air batteries assembled with Co5.47N@N-rGO-750 show a power density of 120.7 mWcm−2 and excellent cycling stabilities for 330 h in an aqueous electrolyte. More interestingly, when assembled into a flexible solid-state rechargeable Zn-air battery, the Co5.47N@N-rGO-750 displays a specific capacity of 610 mAh gzn−1 and good cycling stability over 40 h. Moreover, the integrated device for water splitting powered by Zn-air batteries is also fabricated by using the Co5.47N@N-rGO-750 electrocatalyst, exhibiting a good gas generation rate. This work offers a new strategy to design and synthesize efficient multifunctional carbon-based electrocatalysts applied in electrochemical devices.

Different from the traditional uniaxial stretchable displays, biaxial stretchable devices are herein reported based on a dynamic supramolecular liquid crystal gel network that showed good innovation in a new dimension of the original stretch to obtain the “true stretchable display”. Such biaxial stretchable displays can depict information and images clearly under biaxial forces, which are investigated for breaking the dimensional limitation of traditional uniaxial stretch displays and provide a new perspective for stretchable displays. Unlike the commonly used polymer-based display layer, which was not able to achieve equal and uniform bearing of external forces in perpendicular directions, this unique supramolecular network topography favours the dissipation of tensile forces in two-dimensions through the network structure based on the unique non-oriented assembly. This unique biaxial stretchable optical display paves the way for future stretchable devices.

Exploring cheap and efficient bifunctional electrocatalysts is highly desirable but challenging for sustainable production of hydrogen via electrocatalytic water splitting. Herein, a versatile strategy was demonstrated to controllably synthesize a family of metal ion-chelated tannic acid coatings on diverse metal hydroxide nanoarchitectures via the interfacial coordination assembly process. Typically, the interfacial coordination of tannic acid with a range of metal ions (e.g., Fe3+, Co2+, and Ni2+) enables the in situ formation of metal–ligand networks on nickel hydroxide nanowalls and other hierarchical substrates. Importantly, the obtained hierarchical coordination complex showed that its bifunctional electrocatalytic activity toward the oxygen evolution reaction and hydrogen evolution reaction is highly dependent on the chelated metal ions. The coordination coating of tannic acid with iron ions on nickel hydroxide nanowalls significantly enhanced the bifunctional electrocatalytic activity and achieved maximal activity toward overall water splitting with good long-term durability. This interfacial coordination assembly coating strategy is facile yet efficient, opening a new avenue for rational modulation of the surface properties of metal (hydro)oxides for promising applications.

To explore an efficient photocatalyst for NO pollution, a direct Z-scheme photocatalytic system is successfully fabricated by coupling Bi2WO6 with NH2-UiO-66 via a simple hydrothermal synthesis technique. The Z-scheme system promotes the NO photocatalytic oxidation activity with an optimum NO removal rate of 79%, which is 2.7 and 1.2 times that obtained by using only pristine Bi2WO6 and NH2-UiO-66, respectively. Simultaneously, superior selectivity for converting NO to NO3−/NO2− is observed. The enhanced photocatalytic performance of the Bi2WO6/NH2-UiO-66 hybrids is attributed to the following two aspects: (i) large specific area of NH2-UiO-66, which exposes more active sites and is beneficial to the adsorption and activation of NO; (ii) outstanding Z-scheme structure constructed between BiWO6 and NH2-UiO-66, which can improve the efficiency of the separation of electron–hole pairs and preserves the strong oxidation ability of hybrids. ESR analysis shows that ·O2− and ·OH contribute to NO removal. A possible photocatalytic mechanism of NO oxidation on the direct Z-scheme photocatalyst (BWO/2NU) under visible light irradiation is proposed. This work displays the BWO/2NU hybrid's potential for treating low-concentration air pollutants, and the proposed Z-scheme photocatalyst design and promotion mechanism may inspire more rational synthesis of highly efficient photocatalysts for NO removal.

This letter presents a systematic study of how the substrate bias ( ${V}_{\text {sub}}$ ) modulation affects the current-voltage ( ${I}$ - ${V}$ ) characteristics and low-frequency noise (LFN) of lateral bipolar junction transistors (LBJTs) fabricated on a silicon-on-insulator (SOI) substrate. The current gain ( $\beta$ ) of npn LBJTs at low base voltage can be greatly improved by a positive ${V}_{\text {sub}}$ as a result of enhanced electron injection into the base near the buried oxide (BOX)/silicon interface. However, an excessive positive ${V}_{\text {sub}}$ may also adversely affect the LFN performance by amplifying the noise generated as a result of carrier trapping and detrapping at that interface. Our results provide a practical guideline for improving both $\beta $ and the overall noise performance when using our LBJT as a local signal amplifier.

Laser–plasma accelerators (LPAs) have great potential to realize a compact X-ray free-electron laser (FEL), which is limited by the beam properties currently. Two-color high-intensity X-ray FEL provides a powerful tool for probing ultrafast dynamic systems. In this paper, we present a simple and feasible method to generate a two-color X-ray FEL pulse based on an LPA beam. In this scheme, time-dependent mismatch along the bunch is generated and manipulated by the designed lattice system, enabling FEL lasing at different wavelength within two undulator sections. The time separation between the two pulses can be precisely adjusted by varying the time-delay chicane. Numerical simulations show that two-color soft X-ray FELs with gigawatt-level peak power and femtosecond duration can be generated, which confirm the validity and feasibility of the scheme.

Both myocardial infarction (MI) and the follow-up reperfusion will lead to an inevitable injury to myocardial tissues, such as cardiac dysfunctions, fibrosis, and reduction of intercellular cell-to-cell interactions. Recently, exosomes (Exo) derived from stem cells have demonstrated a robust capability to promote angiogenesis and tissue repair. However, the short half-life of Exo and rapid clearance lead to insufficient therapeutic doses in the lesion area. Herein, an injectable conductive hydrogel is constructed to bind Exo derived from human umbilical cord mesenchymal stem cells to treat myocardial injuries after myocardial infarction-ischemia/reperfusion (MI-I/R). To this end, a hyperbranched epoxy macromer (EHBPE) grafted by an aniline tetramer (AT) was synthesized to cross-link thiolated hyaluronic acid (HA-SH) and thiolated Exo anchoring a CP05 peptide via an epoxy/thiol "click" reaction. The resulting Gel@Exo composite system possesses multiple features, such as controllable gelation kinetics, shear-thinning injectability, conductivity matching the native myocardium, soft and dynamic stability adapting to heartbeats, and excellent cytocompatibility. After being injected into injured hearts of rats, the hydrogel effectively prolongs the retention of Exo in the ischemic myocardium. The cardiac functions have been considerably improved by Gel@Exo administration, as indicated by the enhancing ejection fraction and fractional shortening, and reducing fibrosis area. Immunofluorescence staining and reverse transcription-polymerase chain reaction (RT-PCR) results demonstrate that the expression of cardiac-related proteins (Cx43, Ki67, CD31, and α-SMA) and genes (VEGF-A, VEGF-B, vWF, TGF-β1, MMP-9, and Serca2a) are remarkably upregulated. The conductive Gel@Exo system can significantly improve cell-to-cell interactions, promote cell proliferation and angiogenesis, and result in a prominent therapeutic effect on MI-I/R, providing a promising therapeutic method for injured myocardial tissues.

A boron nitride nanosheet (BNNS)-assisted matrix solid-phase dispersion method was established to microextract alkaloids from medicinal plants. The target compounds were identified by high-performance liquid chromatography coupled with ultraviolet detection and ion mobility quadrupole time-of-flight mass spectrometry. During the experimental process, several important parameters, including the type of dispersant, the amount of dispersant, the grinding time, and the type of elution solvent, were optimized. Finally, the BNNSs were chosen as the best dispersant, and their microcosmic morphologies were identified by scanning electron microscopy and transmission electron microscopy. Because of the special property of BNNSs, the cost of this experiment was greatly reduced, especially in elution volume, sample amount (50 mg), and extraction time (2 min). Under the best conditions, 50 mg of sample powder was dispersed with 50 mg of BNNSs, the grinding time was 120 s, the mixed powder was eluted with 200 μL of methanol, and good linearity (r2 > 0.9993) and satisfactory recoveries (80-100%) were obtained. The inter- and intraday precisions were acceptable, with RSDs lower than 2.01 and 4.84%, respectively. The limits of detection ranged from 2.54 to 15.00 ng/mL, and the limits of quantitation were 8.47 to 50.00 ng/mL. The proposed method was successfully applied for the determination of liensinine, isoliensinine, and neferine in lotus plumule.

Capacitively Coupled Plasma (CCP) is widely used in thin film deposition, dielectric etching and dusty plasma experiments. Plasma generation is important equipment for CCP. It needs to output an adjustable radio frequency voltage within a wide load range. However, the current plasma generation is commonly composed of radio frequency power amplifier and matching network, which leads to either low power density or low frequency stability. In this paper, an inverter topology is proposed. It can realize zero voltage switching (ZVS) operation within a wide load range, thus generating CCP directly. The voltage gain and the ZVS operation condition are analyzed in detail. A step-by-step parameter design method is given. A 13.56-MHz 25-W prototype inverter which can realize ZVS within 0-1.2k$\Omega$0-130pF is tested in CCP discharges with argon, and the experimental results demonstrate the feasibility of the inverter and the effectiveness of the parameter design.

Bio-based polyimide (PI)/halloysite nanotube (HNT) nanocomposites based on 2,5-furandicarboxylic acid were prepared by in situ polymerization. The pristine HNTs were modified by tetraethoxysilane (TEOS) and 4,4′-oxybisbenzenamine (ODA). The bio-based PI/HNT nanocomposite film exhibited lower moisture absorption than pure bio-based polyimide, showing that the water resistance of the bio-based polyimide film was improved. The thermal stability and glass transition temperature (Tg) of PI/HNTs nanocomposites were improved with the addition of modified HNTs. Both the tensile strength and Young’s modulus of bio-based PI/HNTs nanocomposite films were enhanced. A 37.7% increase in tensile strength and a 75.1% increase in Young’s modulus of bio-based PI/HNTs nanocomposite films, with 1 wt% of the modified HNTs, were achieved. The result confirmed that 2,5-furandicarboxylic acid could replace the oil-based material effectively, thus reducing pollution and protecting the environment. Finally, a preparation mechanism to prepare bio-based PI/HNTs nanocomposite is proposed.

The defect localization is a key link and bottleneck for the failure analysis of 3D interconnects. This paper proposes a combined-cylindrical-shape defect model for the nondestructive defects testing and fault localization of TSV channels in 3D stacked dies. The TSV equivalent circuits and defective fault equivalent circuit are established to explain the fault principle. A simple scheme of GSG TSV channels is made, and their simulated results are shown with the frequency from lOOMHz to 20GHz. By fitting the S-parameters of defect TSV chain, the open-circuit defect size and the defect module localization are estimated based on signal integration. The scalable defect localization method is used for multiple stacked dies scheme based on silicon substate.

In this paper, two TDDB test structures of TSV, including Single-TSV and Dual-TSV, have been designed. In order to compare the availability between these two test structures, the electric field simulation and TDDB failure analysis have been carried out. The simulation results show that the Single- TSV is more prone to abnormal breakdown for its higher electric field between surface pads during TDDB test. On the contrary, the Dual- Tsvhas a greater probability of breakdown in the dielectric liner of TSV, because the maximum of electric field is located at the dielectric liner. The conclusion of TDDB failure analysis support the point of simulation. The Dual- Tsvhas better availability than the Single- TSV for the TDDB test of TSV. Furthermore, we discussed the guidelines for the design of TSV TDDB test structures.

This paper aims to investigate the atomic migration voids formation and time-to-failure mechanism of Ball Grid Array (BGA) device. In order to analyze the parameter changes of BGA device, the actual model and corresponding equivalent model are established by using ANSYS Workbench software. In this study, the effect of various migration forces on atomic migration is determined, while the migration divergence calculated by migration force predicts the failure time of solder joints. Conclusions are made that the solder joints at the corners failed faster than those in the center, and migration caused by current crowding is the major reason for atomic migration, stress migration accelerates the process and thermal migration has little effect.

Microstructures and grain structure evolution of solder joints under extreme temperature changes considerably affects its thermomechanical response and lifetime. Thermal shock tests were conducted to study the thermomechanical responses in Sn-3.0Ag-0.5Cu BGA solder bumps. In this work, the in-situ observation was carried out by EBSD and SEM to examine the microstructure and grain structure evolution during thermal shock tests, which provides the accuracy and continuity of the observation. For the Sn-based solder joint containing limited grains, early failure always occurs in certain solder joints where orientation of grain in contact with substrates exhibited relatively high CTE values parallel to the substrates. Elaborated examination of different stages of recrystallization in the same bump identified localized recrystallization occurred at the place with high CTE mismatch. Moreover, the grain structure had changed from cyclic twin to small random oriented grains, which provides additional degradation mechanism. The grain orientation was critical to reliability and lifetime. Inherent anisotropic properties of s-Sn grain play a vital effect on thermomechanical responses, leading to a change in the initiation propagation path of crack and corresponding reliability problems.

With the advantages of high frequency and high power performance capabilities, AlGaN/GaN high-electron-mobility transistors (HEMTs) have attracted more and more attention. However, the reliability under stress conditions limits the application of GaN HEMTs in microwave power markets. In this paper, the effect of temperature and voltage on GaN HEMTs reliability were studied. A temperature cycling test with the temperature range from -55°C to 175°C, a high temperature storage test of 175°C and a steady-state operation life test with the channel temperature of 175°C have been conducted on GaN HEMTs. The variation of key parameters such as drain current (I DS ), threshold voltage (V GS(th) ), gate-to-source leakage current (I Gss ) have been analyzed before and after the test.