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The machining of titanium alloy has attracted much research attention due to its wide application demand and, however, the low material machinability. The mechanochemical effect and ultrasonic tool vibration are regarded as efficient approaches to improving the machining performance of titanium alloy. This study proposes to combine the above two approaches to obtain synergetic benefits in titanium alloy grinding: use the mechanochemical effect to enlarge the brittleness of the chip and simultaneously use the ultrasonic tool vibration to promote crack propagation on the chip. Finite element analysis (FEA) of cutting is first carried out to demonstrate the process principle. Scratching experiments using a single-edge tool are conducted to explore the synergetic process effects by observing the micro/nano morphology of the chip. Fractured chips are generated due to the synergy of mechanochemical effects and ultrasonic tool vibration. Finally, ultrasonic face and side grinding experiments of titanium alloy are performed, respectively. The results show that the mechanochemical effects can further reduce the surface roughness and cutting force in ultrasonic face grinding. The reduction rate of cutting force increases with the increasing ultrasonic amplitude, and the proportion of cutting force reduction has increased from 18 % to 25 %, indicating the existence of a strong synergetic process effect. However, this synergetic process effect is not found in ultrasonic side grinding. Moreover, it has been proved that the benefits of surface active medium (SAM) in ultrasonic face grinding are not caused by lubrication effects.

Creating structural defects in a controlled manner within metal–organic frameworks (MOFs) poses a significant challenge for synthesis, and concurrently, identifying the types and distributions of these defects is also a formidable task for characterization. In this study, we demonstrate that by employing 2-sulfonylterephthalic acid as the ligand for synthesizing Zr (or Hf)-based MOFs, a crystal phase transformation from the common fcutopology to the rare jmttopology can be easily facilitated using a straightforward mixed-solvent strategy. The jmtphase, characterized by an extensively open framework, can be considered a derivative of the fcuphase, generated through the introduction of missing-cluster defects. We have explicitly identified both MOF phases, their intermediate states, and the novel core–shell structures they form using ultralow-dose high-resolution transmission electron microscopy. In addition to facilitating phase engineering, the incorporation of sulfonic groups in MOFs imparts ionic selectivity, making them applicable for osmotic energy harvesting through mixed matrix membrane fabrication. The membrane containing the jmt-phase MOF exhibits an exceptionally high peak power density of 10.08 W m–2under a 50-fold salinity gradient (NaCl: 0.5 M|0.01 M), which surpasses the threshold of 5 W m–2for commercial applications and can be attributed to the combination of large pore size, extensive porosity, and abundant sulfonic groups in this novel MOF material.

Carbon materials with hierarchical porous structures hold great potential for redox electrolyte-enhanced supercapacitors. However, restricted by the intrinsic inert and nonpolar characteristics of carbon, the energy barrier of anchoring redox electrolytes on the pore walls is relatively high. As such, the redox process at the interface less occurs, and the rate of mass transfer is impaired, further leading to a poor electrochemical performance. Here, a ferricyanide anion-philic interface made of in situ inserted boron species into carbon rings is constructed for enhanced charge storage in supercapacitors. Profiting from the unique component-driven effects, the polar anchoring sites on the pore wall can be built to grasp the charged redox ferricyanide anion from the bulk electrolyte and promote the redox process; the dynamics process is fastened correspondingly. Especially, the boron atoms in BC2O and BCO2units with higher positive natural bond orbital values in the carbon skeleton are pinpointed as intrinsic active sites to bind the negatively charged nitrogen atoms in the ferricyanide anion via electrostatic interaction, confirmed by density functional theoretical calculations. This will suppress the shuttle and diffusion effects of the ferricyanide anion from the surface of the electrode to the bulk electrolyte. Finally, the well-designed PC-3 with high content of BC2O and BCO2units can reach 1099 F g–1at 2 mV s–1, which is a more than 2-fold increase over boron-free units of carbon (428 F g–1). The work offers a novel version for designing high-performance carbon materials with unique yet reaction species-philic effects.

Distributed temperature/strain measurement utilizing Brillouin optical fiber sensors in the Internet of Things (IoT) has attracted more attention to achieve state monitoring of large-scale structures. However, the huge amount of measurement data increases the hardware burden and limits the measurement speed. To address this problem, distributed measurement based on sparse spectra of Brillouin optical fiber sensors in IoT is proposed in this article. Nonlocally centralized sparse representation (NCSR) and fast iterative shrinkage thresholding (FIST) algorithms are adopted to sparsely represent and reconstruct the measured Brillouin scattering spectra (BSS), respectively. Compared with other sparse representation and reconstruction algorithms, the performance of NCSR and FIST for signal-to-noise ratio (SNR) enhancement and successful recovery is the best. Only 25% of samples are needed to reconstruct BSS for further extraction of Brillouin frequency shift (BFS) and temperature. The consistency of BFSs obtained from original and reconstructed BSS both in simulation and experimental results indicates that the extracted BFSs and temperatures are reliable and accurate by applying sparse BSS obtained by NCSR and FIST. Different frequency scanning intervals and heating temperatures in the experiment are also considered for analysis and discussion. The proposed method has been demonstrated to be effective in decreasing the quantity of data for acquisition, storage, and further analysis, which is conducive to reducing the system cost and improving the SNR to achieve distributed measurement in IoT.

Augmented reality (AR) has been widely employed in assembly guidance and maintenance as an excellent visualization tool. On this basis, AR technology combined with visual inspection has become a research topic to realize rapid and intuitive quality inspection while reducing operators' workload. This article proposes a novel multitarget, AR-based, assembly result inspection method, in which detected information is matched with prior knowledge via high-precision registration. First, a multimarker-based global registration method is designed to significantly improve the average registration accuracy in large scenes based on the mutual calibration of a few markers. Second, based on the correlation between the inspection target and its AR twin, an image containing multiple mechanical components is segmented according to the locations, and the local images are matched with the prior knowledge for evaluation. Finally, the inspection method is deployed to AR-based assembly inspection system, and its validity is verified on a rocket cabin imitation platform. Experiments show that the proposed inspection method can accurately segment the multitarget image into several images containing a single target according to the prior locations and can verify the assembly results of the targets, running at 15.1 fps.

In this research a 3D FE rotary ultrasonic cutting simulation model of NHCs core material was developed based on Hashin failure criterion and novel ultrasonic circular saw blade cutter system. Further, 3D FE cutting simulation model was validated by performing RUM experiments on ultrasonic machine tool and explored. Cutting force exhibits inverse relation with vibration amplitude and spindle speed of ultrasonic circular saw blade tool, whereas it shows direct relation with feed rate. Finally, an optimised set of processing parameters was obtained by performing series of cutting simulations and verified by experimental work with a novel ultrasonic circular saw blade cutting tool at resonant frequency of 22,050 Hz, spindle speed 3,000 rpm, feed rate 500 mm/min, cutting width 8 mm, cutting depth 2 mm, and vibration amplitude 25 µm. Moreover, this study provides systematic guideline for RUM process optimisation and improvements of surface quality.

As a nano porous thermal insulation material, the precision and low damage machining of silica aerogel composite is very challenging due to its mechanical properties of low strength, poor toughness, and easy cracking. This study proposes an ultrasonic cutting method of ultra-low-density silica aerogel composites by using a bionic micro-serrated tool. First, the ultrasonic cutting mechanism of micro-serrated straight tool is expounded. A novel bionic micro-serrated blade is designed and fabricated, inspired by the serrated mouthparts of the leaf-cutting ant. Then, a theoretical cutting force model of ultrasonic cutting of silica aerogel composites using a micro-serrated blade is proposed. The ultrasonic vibration improves the slice/push ratio of the tool, while the micro-serrated blade reinforces the stress concentration. Moreover, the experimental scheme and surface quality evaluation method are provided. The ultrasonic cutting performance in terms of cutting force and surface quality of silica aerogel composite is analyzed by using a micro-serrated blade. Quantitative parameters such as defect ratio and fractal dimension are utilized to evaluate the machined surface quality of silica aerogel composite. Experimental results demonstrate that ultrasonic cutting using a micro-serrated blade has the lowest cutting force and best surface quality among conventional cutting, ultrasonic cutting, micro-serrated blade, or non-micro-serrated blade. Among several micro-serrated blade with micro-serration spacing of 0, 20, 100, 200, and 400 μm, the lowest cutting force and best surface quality is obtained when the micro-serration spacing is 100 μm, and it indicates that there is an optimal micro-serration spacing to minimize the cutting force due to the adverse effects of micro-serration spacing on the number of stress concentration and the tool chip space. The results of cutting experiments show that a higher ultrasonic amplitude (10 μm) and a lower feed rate (50 mm/min), depth of cut (3 mm), and inclination angle (30°) can improve the processing quality.

Non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), have emerged as important regulators of the immune system and are involved in the control of immune cell biology, disease pathogenesis, as well as vaccineresponses. A repository of ncRNA–immune associations will facilitate our understanding of ncRNA-dependent mechanisms in the immune system and advance the development of therapeutics and prevention for immune disorders. Here, we describe a comprehensive database, RNA2Immune, which aims to provide a high-quality resource of experimentally supported database linking ncRNA regulatory mechanisms to immune cell function, immune disease, cancer immunology, and vaccines. The current version of RNA2Immune documents 50,433 immune–ncRNA associations in 42 host species, including (1) 6690 ncRNA associations with immune functions involving 31 immune cell types; (2) 38,672 ncRNA associations with 348 immune diseases; (3) 4833 ncRNA associations with cancer immunology; and (4) 238 ncRNA associations with vaccine responses involving 26 vaccine types targeting 22 diseases. RNA2Immune provides a user-friendly interface for browsing, searching, and downloading ncRNA–immune system associations. Collectively, RNA2Immune provides important information about how ncRNAs influence immune cell function, how dysregulation of these ncRNAs leads to pathological consequences (immune diseases and cancers), and how ncRNAs affect immune responses to vaccines. RNA2Immune is available at http://bio-bigdata.hrbmu.edu.cn/rna2immune/home.jsp.

BACKGROUND:: Intra-articular injection is a classic strategy for the treatment of early osteoarthritis (OA). However, the local delivery of traditional therapeutic agents has limited benefits for alleviating OA. Exosomes, an important type of extracellular nanovesicle, show great potential for suppressing cartilage destruction in OA to replace drugs and stem cell-based administration. METHODS:: In this study, we developed a thermosensitive, injectable hydrogel by in situ crosslinking of Pluronic F-127 and hyaluronic acid, which can be used as a slow-release carrier to durably retain primary chondrocyte-derived exosomes at damaged cartilage sites to effectively magnify their reparative effect. RESULTS:: It was found that the hydrogel can sustainedly release exosomes, positively regulate chondrocytes on the proliferation, migration and differentiation, as well as efficiently induce polarization of M1 to M2 macrophages. Intra-articular injection of this exosomes-incorporated hydrogel significantly prevented cartilage destruction by promoting cartilage matrix formation. This strategy also displayed a regenerative immune phenotype characterized by a higher infiltration of CD163+regenerative M2 macrophages over CD86+M1 macrophages in synovial and chondral tissue, with a concomitant reduction in pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) and increase in anti-inflammatory cytokine (IL-10) in synovial fluid. CONCLUSION:: Our results demonstrated that local sustained-release primary chondrocyte-derived exosomes may relieve OA by promoting the phenotypic transformation of macrophages from M1 to M2, which suggesting a great potential for the application in OA.

Freshwater purification from wasted water and seawater is crucial in addressing the global problem of water scarcity. Porous fiber felt with a micro/nanostructure emerges as an efficient approach for water purification; however, its production usually relies on chemical postprocessing to create micro/nano structures on the fiber surface, which might pollute the environment. This study proposed an ecofriendly method to produce micro/nanostructured copper fiber felt without chemical treatment. First, a new transverse-feeding vibration cutting is proposed to fabricate micro/nanostructured fibers with controllable structure characteristics. Through the sintering of the structured fibers without postprocessing, the fiber felt can be produced in an ecofriendly way and exhibit special wettability and excellent photothermal properties. Felt-based freshwater purification, including oil–water separation and solar-driven seawater desalination, can be realized effectively. Results show an oil–water separation efficiency of > 90% and a high evaporation rate of water of > 1.08 kg m−2h−1at 73 mW cm−2are achieved, demonstrating the application prospect of the produced fiber felt.

Silica aerogel composite with ultralow density is a kind of highly porous solid with excellent property of thermal conductivity. It is widely used for thermal insulation in aerospace, national defense and military industries. However, silica aerogel composites are difficult to process, due to the poor mechanical properties, low strength and high brittleness. Therefore, it is necessary to investigate the processing characteristics and material removal mechanism of silica aerogel composites. In this article, a cutting model of silica aerogel composites is established firstly and the fracture mechanism of fiber was analyzed. Then the ultrasonic milling and conventional milling experiments were performed respectively to obtain the features of machined surface. Macro morphology and surface roughness of machined surfaces in different process conditions are compared to investigate the influence of different process conditions on the processing quality. Scanning electron microscope (SEM) was used to obtain the micro morphology of processed surfaces. By comparing and analyzing the micro morphology of processed surfaces, the influence of process conditions on removal mechanism was investigated. The theoretical cutting force and experiment cutting force is compared to verify the cutting model. The results show that the burrs and pits decrease with the ultrasonic vibration amplitude, and increase with the tool diameter. Processing quality of up-milling is better than down-milling. It is indicated that shearing and pulling off are the main removal mechanism of silica aerogel composites. When the silica aerogel composites are processed by rotary ultrasonic milling and up milling, the fibers will be mainly removed by shearing mechanism and the proportion of fibers removed by shearing facture mechanism will be improved with the increase of ultrasonic amplitude.

High-aspect-ratio metallic surface microstructures are increasingly demanded in breakthrough applications, such as high-performance heat transfer enhancement and surface plasmon devices. However, the fast and cost-effective fabrication of high-aspect-ratio microstructures on metallic surfaces remains challenging for existing techniques. This study proposes a novel cutting-based process, namely elliptical vibration chiseling (EV-chiseling), for the high-efficiency texturing of surface microstructures with an ultrahigh aspect ratio. Unlike conventional cutting, EV-chiseling superimposes a microscale EV on a backward-moving tool. The tool chisels into the material in each vibration cycle to generate an upright chip with a high aspect ratio through material deformation. Thanks to the tool’s backward movement, the chip is left on the material surface to form a microstructure rather than falling off. Since one microstructure is generated in one vibration cycle, the process can be highly efficient using ultrafast (>1 kHz) tool vibration. A finite element analysis model is established to explore the process mechanics of EV-chiseling. Next, a mechanistic model of the microstructured surface generation is developed to describe the microstructures’ aspect ratio dependency on the process parameters. Then, surface texturing tests are performed on copper to verify the efficacy of EV-chiseling. Uniformed micro ribs with a spacing of 1–10 μm and an aspect ratio of 2–5 have been successfully textured on copper. Compared with the conventional EV-cutting that uses a forward-moving tool, EV-chiseling can improve the aspect ratio of textured microstructure by up to 40 times. The experimental results also verify the accuracy of the developed surface generation model of microstructures. Finally,the effects of elliptical trajectory, depth of cut, tool shape, and tool edge radius on the surface generation of micro ribs have been discussed.

The technique of manufacturing surface micro-/nano- structures to colorize metal surfaces by using elliptical vibrating cutting has been continuously developed and has good industrial potential. However, the image rendering is based on a raster scan path and constant variation of cutting velocity. The process efficiency and stability are significantly restricted. In this study, a new approach is proposed to implement the elliptical vibration texturing in a face turning setup, where the image rendering is achieved by an equidistant spiral tool path and modulation of the tool vibration frequency. The basic principle is that, while moving at a constant surface velocity, the tool follows a variable frequency elliptical vibration to machine gratings with different spacings on the workpiece surface. In order to ensure the uniformity in the radial direction and the consistency of the color under the same frequency excitation, a smoothly accelerated equidistant spiral tool path is designed. In addition, since the running speed of the machine tool is not completely synchronized with the signal of the tool vibration, a compensation method through the pre-experimental calibration test is proposed. The machining test on the ultra-precision lathe is performed. It is found that on the compensated machined image, cumulative errors caused by the asynchronous operation of the lathe and vibration tool are eliminated, which validates the feasibility and effectiveness of the method.

Oxide-/hydroxide-derived copper electrodes exhibit excellent selectivity toward C2+products during the electrocatalytic CO2reduction reaction (CO2RR). However, the origin of such enhanced selectivity remains controversial. Here, we prepared two Cu-based electrodes with mixed oxidation states, namely, HQ-Cu (containing Cu, Cu2O, CuO) and AN-Cu (containing Cu, Cu(OH)2). We extracted an ultrathin specimen from the electrodes using a focused ion beam to investigate the distribution and evolution of various Cu species by electron microscopy and electron energy loss spectroscopy. We found that at the steady stage of the CO2RR, the electrodes have all been reduced to Cu0, regardless of the initial states, suggesting that the high C2+selectivities are not associated with specific oxidation states of Cu. We verified this conclusion by control experiments in which HQ-Cu and AN-Cu were pretreated to fully reduce oxides/hydroxides to Cu0, and the pretreated electrodes showed even higher C2+selectivity compared with their unpretreated counterparts. We observed that the oxide/hydroxide crystals in HQ-Cu and AN-Cu were fragmented into nanosized irregular Cu grains under the applied negative potentials. Such a fragmentation process, which is the consequence of an oxidation–reduction cycle and does not occur in electropolished Cu, not only built an intricate network of grain boundaries but also exposed a variety of high-index facets. These two features greatly facilitated the C–C coupling, thus accounting for the enhanced C2+selectivity. Our work demonstrates that the use of advanced characterization techniques enables investigating the structural and chemical states of electrodes in unprecedented detail to gain new insights into a widely studied system.

The abundance of oxygen vacancies in Ru-WOx-MgOycatalyst facilitates the chemoselective cleavage of C-C bonds in fructose to generate active intermediates and ultimately enhances the production of 1,2-propanediol.

To explore the effect of pore precipitation freezing in different saturated states on mechanical performance for drainage asphalt pavement, the study revealed the freezing behavior characteristics of pore precipitation in different saturated states by combining CT scanning, FEM simulation and mechanical tests. Firstly, the real spatial structure of drainage asphalt mixture was obtained through the CT scanning, and the corresponding FEM simulation model was established. Secondly, the process of pore precipitation freezing in different saturated states was simulated and analyzed, and its influence on the spatial structure of drainage asphalt mixture was obtained. Finally, the effect of pore precipitation freezing in different saturated states on drainage asphalt mixture was proved through mechanical tests. It is found that the effect of pore precipitation freezing on mechanical performance of drainage asphalt mixture is different under different saturated states. With the increase of saturation state, the influence of pore precipitation freezing becomes more obvious, and the difference of stress-strain distribution in spatial structure for drainage asphalt mixture is more prominent. The study explains how pore precipitation freezing in different saturated states affects the mechanical performance for drainage asphalt pavement, providing a theoretical basis for enhancing its durability.

Metal–organic frameworks (MOFs) are often synthesized using various additives to modulate the crystallization. Here, we report the direct imaging of the crystal surface of MOF MIL-101 synthesized with different additives, using low-dose high-resolution transmission electron microscopy (HRTEM), and identify three distinct surface structures, at subunit cell resolution. We find that the mesoporous cages at the outermost surface of MIL-101 can be opened up by vacuum heating treatment at different temperatures, depending on the MIL-101 samples. We monitor the structural evolution of MIL-101 upon vacuum heating, using in situ X-ray diffraction, and find the results to be in good agreement with HRTEM observations, which leads us to speculate that additives have an influence not only on the surface structure but also on the stability of framework. In addition, we observe solid–solid phase transformation from MIL-101 to MIL-53 taking place in the sample synthesized with hydrofluoric acid.

Defect engineering of metal–organic frameworks (MOFs) offers promising opportunities for tailoring their properties to specific functions and applications. However, determining the structures of defects in MOFs—either point defects or extended ones—has proved challenging owing to the difficulty of directly probing local structures in these typically fragile crystals. Here we report the real-space observation, with sub-unit-cell resolution, of structural defects in the catalytic MOF UiO-66 using a combination of low-dose transmission electron microscopy and electron crystallography. Ordered ‘missing linker’ and ‘missing cluster’ defects were found to coexist. The missing-linker defects, reconstructed three-dimensionally with high precision, were attributed to terminating formate groups. The crystallization of the MOF was found to undergo an Ostwald ripening process, during which the defects also evolve: on prolonged crystallization, only the missing-linker defects remained. These observations were rationalized through density functional theory calculations. Finally, the missing-cluster defects were shown to be more catalytically active than their missing-linker counterparts for the isomerization of glucose to fructose. Structural defects are known to exist in metal–organic frameworks (MOFs), and to affect the materials’ properties, but their exact structures have remained difficult to determine. Now, missing-linker and missing-cluster defects have been observed in a MOF using low-dose transmission electron microscopy, enabling their distributions, evolutions during crystallization and effects on the material’s catalytic activity to be explored.

Microstructured surfaces can reduce friction force between two contact pairs in relative motion under hydrodynamic contact. In this study, we evaluate the friction reduction performance of microdimpled surfaces with different cross-sectional profiles generated by nonresonant modulation cutting. Computational fluid dynamics simulation was conducted to simulate the friction reduction effect between surfaces with lubricants. An elliptical modulation texturing method is introduced based on a two-dimensional nonresonant vibration tool, which could generate adjustable high-frequency elliptical tool trajectories. Different dimpled surfaces were generated using three types of tool trajectories. Their influence on the friction reduction and load-carrying capacity were experimentally studied and evaluated by comparing the simulation and experimental results.

Plenty of efforts have been made to reduce the use of low-value care (the care that is not expected to provide net benefits for patients) across the world, but measures of low-value care have not been developed in China. This study aims to develop hospital discharge records-based measures of low-value surgical procedures, evaluate their annual use and associated expenditure, and analyze the practice patterns by characterizing its temporal trends and correlations across rates of different low-value procedures within hospitals.

Encapsulating catalytically active components into zeolites is a way to prepare multifunctional catalysts with unique selectivity and enhanced stability. Previously reported methods for encapsulation were only suitable for encapsulating specific species with a limited loading capacity. Here, we report a general strategy for encapsulating various metal oxides in zeolites. Our strategy is based on the use of directly synthesized hierarchical zeolites with abundant intracrystalline mesopores. Metal oxides that are preloaded in the mesopores by impregnation become encapsulated during a secondary growth process that converts the original hierarchical structure into a bulk structure of zeolite. This method enables the encapsulation of ultrafine particles (2–4 nm) of various metal oxides (CeO2, TiO2, and MnOx) in zeolites with loading as high as >10 wt %. Furthermore, we modify this method to achieve the encapsulation and high dispersion of noble metals (Au and Pt), which would otherwise agglomerate into large particles on the zeolite surfaces, by taking advantage of their strong interactions with metal oxides. The encapsulated metal oxides and metal oxide-supported noble metals demonstrate reactant selectivity, product selectivity, and excellent thermal stability during catalytic oxidation and hydrogenation reactions.

The machining induced edge chipping of hole manufacturing restricts the productivity and design capability of products made from brittle materials. Rotary ultrasonic machining (RUM) has been sufficiently proved as a suitable approach for hole drilling in brittle materials with reduced cutting force and improved hole edge quality. However, apparent edge chipping is still an important restriction of RUM application. In this study, a compound step-taper tool for RUM was designed to further reduce the edge chipping defects via tool design. RUM tests on quartz glass were conducted to evaluate the effectiveness of the compound step-taper tool. The experimental results demonstrated that the compound tool could reduce the edge chipping size at the hole exit and entrance by 60%–80% and 35%–50%, respectively. The mechanism of edge chipping reduction at the hole exit is that cutting force decreased as the undrilled thickness decreased. This is due to the wedge-type contact structure between the tool’s taper face and the workpiece material. Furthermore, the edge chipping reduction at the hole entrance occurs because of the shielding effect of residual cracks. Residual cracks produced by the second outermost abrasives of the tool’s taper face suppressed the initiation and propagation of lateral cracks that were produced by the outermost abrasives of the tool’s taper face. Theoretical analysis indicated that the compound tool step is beneficial for guaranteeing the effectiveness of tool’s taper face.

Vibration-assisted cutting that utilizes a time-varying cutting trajectory has showed superior performance in ductile-mode cutting of various brittle materials, such as glass and cemented carbide. The knowledge regarding the ductile-to-brittle transition condition is a fundamental issue to regulate and ensure high surface integrity in ductile-mode cutting of brittle materials. Specifically, in vibration cutting of brittle materials, the vibration trajectory has a critical influence on the ductile-to-brittle transition. Due to the anisotropy of material property with respect to the cutting direction, the ductile-to-brittle transition of single crystal silicon in vibration cutting is rather complicated. This study focuses on the study of the ductile-to-brittle transition in single crystal silicon considering the effects of the design of tool vibration trajectories. A non-resonant vibration tool thus has been developed to generate various kinds of two-dimensional tool trajectories, such as elliptical and trapezoidal shapes. The effects of trajectory shape on the nominal depth-of-cut are analyzed experimentally in this preliminary study.

This study aims to investigate the environmental and individual factors contributing to male nurses' psychological well-being and to explore the psychological mechanisms that may explain the links between nurses' practice environment and work engagement, thereby presenting the implications for nurse managers.

With concerns of diminishing fossil fuel reserves and environmental deterioration, great efforts have been made to explore novel approaches of efficiently utilizing bio-renewable feedstocks to produce chemicals and fuels. 5-Hydroxymethylfurfural (HMF), generated from dehydration of six-carbon ketose, is regarded as a primary and versatile renewable building block to realize the goal of production of these high valued products from renewable biomass resources transformation. In this review, we summarize the recent advances via green routes in the heterogeneous reaction system for the catalytic production of HMF from glucose conversion, and emphasize reaction pathways of these reaction approaches based on the fundamental mechanistic chemistry as well as highlight the challenges (such as separation and purification of products, reusing and regeneration of catalyst, recycling solvent) in this field.

The edge chipping of holes, which is induced by mechanical machining, restricts the applications of brittle materials. Rotary ultrasonic machining is considered a suitable approach to machine holes in brittle materials with a smaller edge-chipping size. However, obvious edge chipping at the hole exit in rotary ultrasonic machining remains observable. In this study, conical diamond core drills with various characteristic angles (θ) were designed to further reduce the edge-chipping size for rotary ultrasonic machining. Machining tests on quartz glass were conducted to evaluate the effectiveness of this new type of drill. Experimental results show that the conical drill can obviously reduce the edge-chipping size only when certain conditions are satisfied. The mechanism of edge-chipping reduction using a conical drill was revealed by the theoretical analysis and detailed observation of the thrust force and obtained cylinder. To guarantee the feasibility of the conical drill, its characteristic angle should exceed a critical value at a certain feed rate. A higher feed rate requires a higher critical characteristic angle. The other advantage of the conical drill is its ability to suppress the bad effects of increasing the feed rate on the stability of ultrasonic vibration.

Traditional solar–thermal receivers suffer from high surface temperatures, which increase heat losses to the surroundings. To improve performance, volumetric receivers based on nanoparticles suspended in liquid (nanofluids) have been studied as an approach to reduce surface losses by localizing high temperatures to the interior of the receiver. Here, we report measured vapor generation efficiencies of 69% at solar concentrations of 10sun using graphitized carbon black, carbon black, and graphene suspended in water, representing a significant improvement in both transient and steady-state performance over previously reported results. To elucidate the vapor generation mechanism and validate our experimental results, we develop numerical and analytical heat transfer models that suggest that nanofluid heating and vapor generation occur due to classical global heating of the suspension fluid. This work demonstrates high nanofluid-assisted vapor generation efficiencies with potential applications in power generation, distillation, and sterilization.

Wi-Fi fingerprint indoor localisation method is widely used owing to its low cost and relatively high accuracy. However, a primary problem for fingerprinting is that different devices receive different signal strength even at the same time and in the same place, thus affecting the localisation accuracy extremely. We propose a new method which makes use of RSS histogram generated by radio map and real-time RSS sequence respectively to form a linear relationship between reference devices and users’ devices. Therefore, once an observed RSS is received, it is transformed to a new fingerprint to fit the radio map. Our experiments use two different devices to verify the RSS-calibration method’s performance compared with that of no calibration and manual calibration. And it indicates that the localisation accuracy is improved by about 2 m.

By using cetyltrimethylammonium bromide (CTAB) as the template, a series of mesoporous niobium phosphates were synthesized at different pH values in an aqueous solution. Techniques such as small-angle X-ray diffraction, transmission electron microscopy (TEM) and N2sorption technique were employed to characterize the mesoporous structures of thus-synthesized materials, EDAX to detect the composition, FTIR and solid state 31P MAS NMR to investigate the framework information, while their acidic properties were analyzed using NH3-TPD and pyridine-FTIR. Samples prepared at neutral to acidic conditions exhibited high surface area (213–297 m2g−1), narrow pore size distribution (3–4 nm) and a great number of strong Lewis and Brönsted acid sites. These materials exhibited excellent activity in the dehydration of fructose to 5-hydroxymethylfurfural (HMF) in water. The maximum HMF yield reached 45% under 130 °C with a reaction time of 0.5 h and the yield slightly decreased to 32% after five cycles and the five-cycled catalyst can be almost regenerated by calcination at 500 °C with the yield of 40%. The excellent catalytic activity obtained in the aqueous phase can be attributed to its high acid site density and the tolerance to water.

With the development of ultralow-dose (scanning) transmission electron microscopy ((S)TEM) techniques, atomic-resolution imaging of highly sensitive nanomaterials has recently become possible. However, applying these techniques to the study of sensitive bulk materials remains challenging due to the lack of suitable specimen preparation methods. We report that cryogenic focused ion beam (cryo-FIB) can provide a solution to this challenge. We successfully extracted thin specimens from metal–organic framework (MOF) crystals and a hybrid halide perovskite single-crystal film solar cell using cryo-FIB without damaging the inherent structures. The high quality of the specimens enabled the subsequent (S)TEM and electron diffraction studies to reveal complex unknown local structures at an atomic resolution. The obtained structural information allowed us to resolve planar defects in MOF HKUST-1, three-dimensionally reconstruct a concomitant phase in MOF UiO-66, and discover a new CH3NH3PbI3structure and locate its distribution in a single-crystal film perovskite solar cell. This proof-of-concept study demonstrates that cryo-FIB has a unique ability to handle highly sensitive materials, which can substantially expand the range of applications for electron microscopy.

Non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), have emerged as important regulators of the immune system and are involved in the control of immune cell biology, disease pathogenesis, as well as vaccineresponses. A repository of ncRNA–immune associations will facilitate our understanding of ncRNA-dependent mechanisms in the immune system and advance the development of therapeutics and prevention for immune disorders. Here, we describe a comprehensive database, RNA2Immune, which aims to provide a high-quality resource of experimentally supported database linking ncRNA regulatory mechanisms to immune cell function, immune disease, cancer immunology, and vaccines. The current version of RNA2Immune documents 50,433 immune–ncRNA associations in 42 host species, including: (1) 6690 ncRNA associations with immune functions involving 31 immune cell types; (2) 38,672 ncRNA associations with 348 immune diseases; (3) 4833 ncRNA associations with cancer immunology; and (4) 238 ncRNA associations with vaccine responses involving 26 vaccine types targeting 22 diseases. RNA2Immune provides a user-friendly interface for browsing, searching, and downloading ncRNA–immune system associations. Collectively, RNA2Immune provides important information about how ncRNAs influence immune cell function, how dysregulation of these ncRNAs leads to pathological consequences (immune diseases and cancers), and how ncRNAs affect immune responses to vaccines. RNA2Immune is available at http://bio-bigdata.hrbmu.edu.cn/rna2immune/home.jsp.

Carbonaceous catalysts with sulfonic acid (-SO3H) groups are showing promising performances in the conversion of mono- and poly-saccharides, however, their applications in the hydrodeoxygenation (HDO) of oxygen-rich lignin derivatives are rarely reported. Herein, we report a facile synthetic approach for one-step preparation of porous carbonaceous solid acids with –SO3H groups (OHCA) where monosaccharide, polysaccharide, and raw biomass can be used as carbon precursors. These porous carbonaceous solid acids supported ultrafine palladium nanoparticles (Pd/OHCA) exhibited excellent performances in the HDO of vanillin (VAN) in water. We found that Pd nanoparticles (Pd NPs) were responsible for the hydrogenation of VAN to vanillyl alcohol (VAL) and acidic groups were crucial for the hydrogenolysis of generated VAL to 2-methoxy-4-methylphenol (MMP). Importantly, VAL once generated can be immediately converted to MMP via synergistic catalysis between acidic groups and Pd NPs, avoiding the formation of by-products. Pd/OHCA catalyst also exhibited excellent stability in the HDO of VAN and retained its activities in the six consecutive runs. The findings of this work provide a new thought for the HDO of biomass derivatives over biomass-based carbon catalysts.

The study investigates different ways of preservation and popularization of Chinese traditional music using the Internet. The study collected data by analyzing various methods of presenting traditional Chinese music in online platforms YouTube, TikTok, and Likee. Common groups for YouTube are instrumental music (46.8%) and vocal music (23.9%), whereas, for TikTok and Likee, it is dancing performances (68.6% and 71.8%) and instrumental music (21.6% and 22.3%). The samples containing information about the content on the online platforms YouTube and TikTok are continuously growing in August, October, and December, while the Likee platform has seen a decline in all indicators. For the online platform YouTube, the largest increases were seen for vocal music theory and instrumental music for August, October, and December, while for the TikTok platform, the corresponding indicators were for Chinese music theory and educational dance performances in August and October. For online platform Likee for the aforementioned months, vocal music has seen the biggest decline over time. The obtained data can be useful for a better understanding of the audience’s requests, which makes it possible to popularize music content more productively. The authors see such study as necessary for the implementation of new business projects in the operation of online music platforms, changes in approaches to licensing over the Internet, and reform of the music industry. The development of the Internet popularizes Chinese musical culture on a global scale, opens up new opportunities for the Chinese population (professionals and amateurs, adults and children) to study the musical heritage of other countries, promotes musical diversity, and can bring substantial financial benefits not only to individuals or companies, but also to the state as a whole.