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Rheumatoid arthritis (RA) is a chronic disease characterized by immune cell infiltration and cartilage damage. The local lesion of RA shows severe oxidative stress and proinflammatory cytokine secretion. For drug therapy, the efficacy of agents, such as methotrexate (MTX), may be greatly limited, resulting from the low bioavailability, immune clearance, and toxic side effects. A nanocarrier (TA-PBA NPs) was developed with anti-inflammatory and antioxidant activities, combined with MTX to prepare nanomedicine (MTX NPs) for synergistic treatment of RA. Moreover, inspired by the biological functions homing to inflammation lesion of macrophages, the biomimetic nanomedicine camouflaged with macrophage membrane (MM@MTX NPs) was constructed. TA-PBA NPs could timely promote MTX release in response to the overaccumulated ROS to exhibit high anti-inflammatory and antioxidant activities for alleviating RA progression. The experimental results confirmed that MM@MTX NPs could significantly reduce the secretion of proinflammatory cytokines (TNF-α) while significantly increasing the typical anti-inflammatory cytokines (IL-10), promote the phenotype transformation of macrophages from M1 to M2, and up-regulate the Nrf2-keap1 pathway-related proteins (HO-1 and NRF2) to positively regulate the local inflammation for effectively inhibiting RA development. Thus, MM@MTX NPs represent a possible candidate as a safe and efficient nanotherapy platform for RA management.

A cautious projection BFGS method is proposed for solving nonconvex unconstrained optimization problems. The global convergence of this method as well as a stronger general convergence result can be proven without a gradient Lipschitz continuity assumption, which is more in line with the actual problems than the existing modified BFGS methods and the traditional BFGS method. Under some additional conditions, the method presented has a superlinear convergence rate, which can be regarded as an extension and supplement of BFGS-type methods with the projection technique. Finally, the effectiveness and application prospects of the proposed method are verified by numerical experiments.

The uniformity and monodispersity of the chitosan microsphere are essential requirements for its related applications, and the appearance of undesired satellite droplets needs to be avoided. However, preparing monodispersed, uniform, and size-controllable chitosan microspheres is still a significant challenge. In this paper, a droplet-based microfluidic strategy is developed for the chitosan and fluorescent chitosan microsphere synthesis with controllable size and monodispersity. A water-in-oil droplet microfluidic reaction system is formed, and the monodispersed viscous droplet generation one by one in a step T-junction microchannel and solidified microspheres is observed via a chemical cross-reaction. A side microchannel is designed to separate satellite droplets successfully and improve the quality of the product. The effects of flow rates of two phases, phase ratio, and reaction time are investigated experimentally. The stable operating range for viscous droplets is given. The size of the chitosan could be tuned from 50 to 200 μm, and the production rate could reach up to 1.2 mL·h–1. This work not only provides valuable guidance for polymer microsphere synthesis but also helps to understand the microdispersion mechanism of the non-Newton viscous fluid in depth.

Microfluidic paper-based analytical devices (μPADs) feature an economic and sensitive nature, while acoustofluidics displays contactless and versatile virtue, and both of them gained tremendous interest in the past decades. Integrating μPADs with acoustofluidic techniques provides great potential to overcome the inherent shortcomings and make appealing achievements. Here, we present acoustofluidics-assisted multifunctional paper-based analytical devices that leverage bulk acoustic waves to realize multiple applications on paper substrates, including uniform colorimetric detection, microparticle/cell enrichment, fluorescence amplification, homogeneous mixing, and nanomaterial synthesis. The glucose detection in the range of 5–15 mM was conducted to perform uniform colorimetric detection. Various types (brass powder, copper powder, diamond powder, and yeast cells) and sizes (5–200 μm) of solid particles and biological cells can be enriched on paper in a few seconds or minutes; thus, fluorescence amplification by 3 times was realized with the enrichment. The high-throughput and homogeneous mixing of two fluids can be achieved, and based on the mixing, nanomaterials (ZnO nanosheets) were synthesized on paper. We analyzed the underlying mechanisms of these applications in the devices, which are attributed to Faraday waves and Chladni patterns. With their simple fabrication and prominent effectiveness, the devices open up new possibilities for paper-based microfluidic devices.

A new 3T1R parallel manipulator (PM) 2PPaRR-2PPaRU with rotational pitch motion is proposed in this paper. In such a mechanism, there are four limbs connected to the moving platform (MP) through several revolute joints and universal joints, and all actuated joints are prismatic joints with an axis along a vertical direction. Mobility and motion characteristics are verified by constraint screw theory. The inverse kinematic solutions and the singularity configurations are derived through kinematic analysis. Next, the workspace analysis and the connection between ϕand the volume of the reachable workspace are performed. The local motion/force transmission index is selected to evaluate the local transmission performance of 2PPaRR-2PPaRU PM. Finally, the global motion/force transmission index and the volume of reachable workspace are considered simultaneously to optimize the structural parameters. The 2PPaRR-2PPaRU PM with improved local transmission performance and reachable workspace has been achieved after optimization.

Assembly interfaces, the joint surfaces between the vertical tail and rear fuselage of a large aircraft, are thin-wall components. Their machining quality are seriously restricted by the machining vibration. To address this problem, an in-process adaptive milling method is proposed for the large-scale assembly interface driven by real-time machining vibration data. Within this context, the milling operation is first divided into several process steps, and the machining vibration data in each process step is separated into some data segments. Second, based on the real-time machining vibration data in each data segment, a finite-element-unit-force approach and an optimized space–time domain method are adopted to estimate the time-varying in-operation frequency response functions of the assembly interface. These FRFs are in turn employed to calculate stability lobe diagrams. Thus, the three-dimensional stability lobe diagram considering material removal is acquired via interpolation of all stability lobe diagrams. Third, to restrain milling chatter and resonance, the cutting parameters for next process step, e.g., spindle speed and axial cutting depth, are optimized by genetic algorithm. Finally, the proposed method is validated by a milling test of the assembly interface on a vertical tail, and the experimental results demonstrate that the proposed method can improve the machining quality and efficiency of the assembly interface, i.e., the surface roughness reduced from 3.2 μm to 1.6 μm and the machining efficiency improved by 33%.

To construct a unified model of complex adaptive milling system for thin-walled parts, this paper proposed a continuous-discrete hybrid adaptive milling system driven by in-process data. Firstly, in-process data are collected to construct the information model of machining system, which is used for process parameters adaptive optimization. Then, the machining chatter and error are taken as continuous variables. Typical operations are packed as services, and the random states are defined as discrete events. Finally, finite state automata is employed for modelling the service-oriented hybrid adaptive milling system. Based on the proposed unified model, a prototype system of adaptive milling contained hardware and software is developed to verify the proposed methodology and system. The unified finite state automata model of service-oriented continuous-discrete hybrid adaptive milling can provide theoretical fundamentals for the control and management of complex adaptive milling system for thin-walled parts.

A foot-driven rehabilitation mechanism is suitable for home healthcare due to its advantages of simplicity, effectiveness, small size, and low price. However, most of the existing studies on lower limb rehabilitation movement only consider the trajectory of the ankle joint and ignore the influence of its posture angle, which makes it difficult to ensure the rotation requirements of the ankle joint and achieve a better rehabilitation effect. Aiming at the shortcomings of the current research, this paper proposes a new single degree-of-freedom (DOF) configuration that uses a noncircular gear train to constrain the three revolute joints (3R) open-chain linkage and expounds its dimensional synthesis method. Then, a parameter optimization model of the mechanism is established, and the genetic algorithm is used to optimize the mechanism parameters. According to the eight groups of key poses and position points of the ankle joint and the toe, the different configurations of the rehabilitation mechanism are synthesized and compared, and it is concluded that the newly proposed 3R open-chain noncircular gear-linkage mechanism exhibits better performance. Finally, combined with the requirements of rehabilitation training, a lower limb rehabilitation training device is designed based on this new configuration, and a prototype is developed and tested. The test results show that the device can meet the requirements of the key position points and posture angles of the ankle joint and the toe and verify the correctness of the proposed dimensional synthesis and optimization methods.

Ultra-high-purity silicon tetrachloride (SiCl4) is demanded as an electronic-grade chemical to meet the stringent requirements of the rapidly developing semiconductor industry. The high requirement for ultra-high-purity SiCl4has created the need for a high-efficient process for reducing energy consumption as well as satisfying product quality. In this paper, a mass of production technology of ultra-high-purity SiCl4was successfully developed through chlorination reaction in the ultraviolet (UV)-based photo microreactor coupled with the distillation process. The influences of key operational parameters, including temperature, pressure, UV wavelength and light intensity on the product quality, especially for hydrogen-containing impurities, were quantified by the infrared transmittance of Fourier transform infrared spectroscopy (FT-IR) at 2185 cm−1and 2160 cm−1indicating that characteristic vibrational modes of SiH bonds, as well as the operating conditions of distillation were also investigated as key factors for metal impurities removing. The advanced intensification of SiCl4manufactured by the integration of photo microreactor and distillation achieves the products with superior specifications higher than the standard commercial products.

The elements of Green function matrix are the nonlinear functions of fault parameters estimation, the randomness of fault parameters estimation causes that the slip distribution inversion turns to be the parameter estimation problem of total least squares. Second-order approaching function method, scaled unscented transformation (SUT) method and adaptive Monte Carlo method are designed for biases of displacements in rectangular dislocation model. They are used to analyze effects of the length, width, depth and dip of fault with different variances on the corresponding displacements of unit strike slip dislocation fault, unit dip slip dislocation fault and unit tensile dislocation fault. Results of the simulated fault show that compared with second-order approaching function method and adaptive Monte Carlo method, SUT method has better computational efficiency. The second-order term has dominant effects on nonlinear relationship between displacements and the fault parameter in the rectangular dislocation model. The main biases of displacements are near to fault. The corresponding displacements of unit tensile dislocation are mostly susceptible to fault parameters estimation, followed by the unit dip slip dislocation and unit strike slip dislocation. In addition, the vertical displacement is more sensitive to fault parameters estimation than horizontal displacements.

Stem cell therapy represents the potential alternative effective strategy for some diseases that lack effective treatment currently. Correspondingly, it is crucial to establish high-sensitive and reliable quantification assay for tracing exogenous cell migration. In the present study, we first used both bioluminescence imaging (BLI) indirect labeling (human norepinephrine transporter-luciferase reporter system) and 89zirconium (89Zr)-hNSCs direct labeling combined with positron emission tomography/computer tomography (PET/CT) system for tracking human neural stem cells (hNSCs) migration into the brain via nasal administration in preclinical study. But the above two methods failed to give the biodistribution profile due to their low sensitivity. Considering its superior sensitivity and absolute quantitation capability, we developed and validated the droplet digital PCR (ddPCR) targeting species-specific gene in frozen and paraffin sections, slices, and whole blood with the sensitivity of 100–200 hNSCs. Accurate and high throughput quantification could be performed using ddPCR with the coefficient of variation (CVs) of lower quality control (LQC) below 30%. In combination with immunohistochemistry and ddPCR, we confirmed the migration of hNSCs into the brain via nasal administration, which supported the efficacy of hNSCs in MPTP-treated mice, an animal model of Parkinson’s disease. In conclusion, the present study is the first to report the application of ddPCR in the pharmacokinetics profile description of tracking of hNSCs in preclinical studies.

Multi-robots collaborative milling system (MRCMS) can significantly enhance the machining efficiency of multi-feature parts that widely served in aerospace manufacturing; however, the machining quality is seriously restrict by the chatter. To cope with this problem, a chatter stability prediction method for MRCMS is proposed in the paper. Firstly, the chatter stability model of single-robot milling system is constructed while considering both the regenerative effect and modal coupling effect. Then, based on the model, the coupling of the two cutting forces in double-robots collaborative milling system (DRCMS) is expressed as the relationship between frequency response function (FRF) and its delay term, which is used for chatter stability model construction of DRCMS. Finally, the coupling of multi cutting forces is considered to construct the chatter stability model for MRCMS. The zero-order approximate (ZOA) method is adopted to solve above models to obtain the stability lobe diagram (SLD), which is used for chatter stability prediction and cutting parameters optimization of MRCMS.

Harmful machining vibration including milling chatter and resonance are easily generated during robotic milling process, and it seriously restrict the machining ability of the robot. To address this problem, a harmful machining vibration-controlled method based on the combined optimization of milling posture and spindle speed is proposed for robotic milling system in this paper. With this context, firstly, the robot stiffness model is established based on the theory of the multi-body with small-deformation, and the stiffness ellipsoid at the tool cutting point is used to optimize the milling posture, so that the structure stiffness of the robot can be enhanced; Then, the robot chatter stability model is constructed considering the modal coupling effect, and the spindle speed is optimized to restrain the milling chatter and resonance. Finally, with the optimized milling posture and spindle speed, the milling process is planned and performed with a Staubli TX-200 robot, and two experiments for workpiece with steel and aluminum are implemented to verify the proposed method. The experiment results demonstrate that the comprehensive optimization of milling posture and spindle speed can efficiently control the harmful machining vibration for the robotic milling system, thus, the machining quality of the workpiece can be improved.

Atherosclerotic plaques exhibit high cholesterol deposition and oxidative stress resulting from high reactive oxygen species (ROS). These are the major components in plaques and the main pro-inflammatory factor. Therefore, it is crucial to develop an effective therapeutic strategy that can simultaneously address the multiple pro-inflammatory factors viaremoving cholesterol and inhibiting the overaccumulated ROS. In this study, we constructed macrophage membrane-encapsulated biomimetic nanoparticles (MM@DA-pCD@MTX), which not only alleviate cholesterol deposition at the plaque lesion viareverse cholesterol transport but also scavenge the overaccumulated ROS. β-Cyclodextrin (β-CD) and the loaded methotrexate (MTX) act synergistically to induce cholesterol efflux for inhibiting the formation of foam cells. Among them, MTX up-regulated the expression of ABCA1, CYP27A1, and SR-B1. β-CD increased the solubility of cholesterol crystals. In addition, the ROS scavenging property of dopamine (DA) was perfectly preserved in MM@DA-pCD@MTX, which could scavenge the overaccumulated ROS to alleviate the oxidative stress at the plaque lesion. Last but not least, MM-functionalized “homing” targeting of atherosclerotic plaques not only enables the targeted drug delivery but also prolongs in vivocirculation time and drug half-life. In summary, MM@DA-pCD@MTX emerges as a potent, multifunctional therapeutic platform for AS treatment, offering a high degree of biosafety and efficacy in addressing the complex pathophysiology of atherosclerosis.

Hydrogel microspheres are biocompatible materials widely used in biological and medical fields. Emulsification and stirring are the commonly used methods to prepare hydrogels. However, the size distribution is considerably wide, the monodispersity and the mechanical intensity are poor, and the stable operation conditions are comparatively narrow to meet some sophisticated applications. In this paper, a T-shaped stepwise microchannel combined with a simple side microchannel structure is developed to explore the liquid–liquid dispersion mechanism, interfacial evolution behavior, satellite droplet formation mechanism and separation, and the eventual successful synthesis of dextran hydrogel microspheres. The effect of the operation parameters on droplet and microsphere size is comprehensively studied. The flow pattern and the stable operation condition range are given, and mathematical prediction models are developed under three different flow regimes for droplet size prediction. Based on the stable operating conditions, a microdroplet-based method combined with UV light curing is developed to synthesize the dextran hydrogel microsphere. The highly uniform and monodispersed dextran microspheres with good mechanical intensity are synthesized in the developed microfluidic platform. The size of the microsphere could be tuned from 50 to 300 μm with a capillary number in the range of 0.006–0.742. This work not only provides a facile method for functional polymeric microsphere preparation but also offers important design guidelines for the development of a robust microreactor.

When the load changes frequently during the operation of a tree transplanting machine, the load power of the hydraulic pump fluctuates greatly, causing the engine to frequently work in a high fuel consumption mode and suffer serious power loss. To enable the working device of a tree transplanting machine to save energy when operating under a variable load, power matching between the engine and the hydraulic pump is required. In this article, a power matching control system is designed based on the working device and hydraulic system of a tree transplanting machine and is modelled and simulated by AMESim software. A power matching control test system is also built and tested. The modelling, simulation and testing results show that the power matching control system can stabilize the engine speed near the target speed and achieve an obvious energy-saving effect, reducing fuel consumption by 9.79% compared to that of the traditional hydraulic system.

In order to improve the anticorrosion ability of a Mg-5Zn-1.5Ca alloy used as a bone replacement material, this study prepared the MnCaP conversion coating, which was formed from a phosphating solution mixed with a MnCl2 solution of 0.05 molarity, on a magnesium (Mg) alloy. After forming a MnCaP conversion coating on a Mg alloy, micro-arc oxidation (MAO) proceeded for improving the anticorrosion ability of the sample. As a result, when the 0.05MnCaP coating on a Mg alloy was immersed in the simulated body fluid (SBF), the corrosion current, pH value change, and hydrogen evolution volume of the SBF solution are lower than a uncoated Mg alloy. From the SEM and EDS analyses for a corroded 0.05MnCaP coating on a Mg alloy, the manganese (Mn) phosphate in a lumpy-rock form and the calcium (Ca) phosphate in a flake form alternate to each other densely, so that the coating can effectively prevent a Mg alloy from corrosion.

Poly(methyl methacrylate) (PMMA), the most common bone cement, has been used as a graft substitute in orthopedic surgeries such as vertebroplasty. However, an undesirable minor crack in the bone–cement interface provoked by shrinkage during polymerization and high elastic modulus of conventional PMMA bone cement dramatically increases the risk of vertebral body refracture postsurgery. Thus, herein, a hydrophilous expandable bone cement was synthesized based on a PMMA commercial cement (Mendec Spine Resin), acrylic acid (AA), and styrene (St). The two synthesized cements (PMMA-PAA, PMMA-PAA-PSt) showed excellent volumetric swelling in vitro and cohesive bone–cement contact in rabbit femur cavity defect. The elastic modulus and compressive strength of the new cements were lower than PMMA. Furthermore, the in vitro analysis indicated that the new cements had lower cytotoxicity than PMMA, including superior proliferation and lower apoptotic rates of Sprague–Dawly rat-derived osteoblasts. Western blotting for protein expression and RT-PCR analysis of osteogenesis-specific genes were conducted on SD rat-derived osteoblasts from both PMMA and new cements films; the results showed that new cements enhanced the expression of osteogenesis-specific genes. Scanning electron microscopy demonstrated improved morphology and attachment of osteoblast on new cement discs compared to the PMMA discs. Additionally, the histological morphologies of the bone–cement interface from the rabbit medial femoral condyle cavity defect model revealed direct and cohesive contact with the bone in the new cement groups in contrast to a minor crack in the PMMA cement group. The sign of a new bone growing into the cement has been found in the new cements after 12 weeks, thereby indicating the osteogenic capacity in vivo. In conclusion, the synthesized hydrophilous expandable bone cements based on PMMA and poly(acrylic acid) (PAA) are promising candidates for vertebroplasty.

With the increasing proportion of installed renewable energy power generation capacity and the introduction of quantitative energy storage policies for new energy power generation. In view of the influence of intermittent and volatility of distributed generation on the safe of power grid, it’s particularly important in the future to equip reasonable energy storage to ensure the flexibility of power system. In this paper, a load frequency control (LFC) strategy of hybrid energy storage based on fractional order proportion integral derivative (FOPID) is proposed to solve the frequency modulation problem of battery energy storage system (BESS) and pumped storage station (PSS) participating in the interconnection network. Firstly, the LFC model is established under the nonlinear factors such as regulator dead zone and generation rate constraint on a two-area reheat steam turbine. Secondly, a FOPID controller is designed. Furthermore, the combined LFC simulation is carried out by adding BESS under the two working operations of PSS generating and pumping. Finally, the influence of demand response is considered in the hybrid energy storage control.

When estimating a coseismic slip distribution with multiple observation types, the relative weight ratios (the contribution ratios of all kinds of actual observations in the joint inversion, which should be positive by default) and regularization parameter critically impact the inversion accuracy. In this paper, we propose a new method for determining the relative weights of multiple observations of jointing inversion slip distributions. This method regards the observations and the relative weight ratios as the training data sets and training parameters, respectively; in addition, the constructed Loss$Loss$function was optimized by the gradient descent method and the exponential decay learning rate method under the TensorFlow platform (GDED). We compared the GDED method with the Helmert variance component estimation method (HVCE) and Akaike's Bayesian information criterion method (ABIC) by designing eight simulation experiments. These simulations included changing the errors and resolutions of the observations, the grid size, the strike angle and the dip angle of the fault, the moment magnitudes of earthquakes, the number of observation types, and the complexity of subduction‐zone earthquakes. We analyzed and discussed the characteristics of the above three methods in determining the relative weight ratios during the joint inversion process. The results of these simulation experiments showed that the GDED method and the ABIC method perform much better than the HVCE method when negative variance occurs in the HVCE method, while the accuracies of the slip distributions produced by the three methods were similar when no negative variance occurred; the GDED method can be used to prevent the occurrence of negative variance compared to the HVCE method and is more time efficient than the ABIC method. Furthermore, we applied these methods to invert the source parameters of the 2015 Mw 8.3 Illapel earthquake (in Chile), and the inversion results showed that the slip of the Illapel earthquake was mainly distributed at depths of approximately 10–50 km. The maximum slip of the Illapel earthquake was approximately 7.9 m, distributed 50–70 km northwest of the epicenter at depths of approximately 10–20 km. Different geodetic observations have distinct characteristics due to their unique observation technologies; for example, global positioning system data have a high temporal resolution but a low spatial resolution, while InSAR data have a high spatial resolution but a low temporal resolution. The spatial and temporal resolutions of the inversion results can be guaranteed by combining these two observations to invert the coseismic slip distribution. The joint estimation of the coseismic slip distribution is a research hotspot in the field of seismic source parameter inversions. However, different combinations of relative weight ratios between these two observations may lead to great differences when jointing estimation of the slip distribution. Determining the relative weight ratios of all kinds of observations (actual observations and virtual observations) during the joint inversion process is a key issue. The previous methods used to solve this problem have shortcomings such as subjectivity, low computational efficiency, and unstable effects. Herein, we developed the GDED method and compared it with the HVCE method and ABIC method through system simulation experiments and actual earthquake experiments. We proposed the GDED method to determine the relative weight ratios of multiple types observations for coseismic slip distribution inversionThe GDED method was more applicable than Helmert variance component estimation method (HVCE) method and Akaike’s Bayesian information criterion method (ABIC) method through the eight simulation experimentsWe applied the GDED method, the HVCE method and the ABIC method to invert the source parameters of the 2015 Mw 8.3 Illapel earthquake We proposed the GDED method to determine the relative weight ratios of multiple types observations for coseismic slip distribution inversion The GDED method was more applicable than Helmert variance component estimation method (HVCE) method and Akaike’s Bayesian information criterion method (ABIC) method through the eight simulation experiments We applied the GDED method, the HVCE method and the ABIC method to invert the source parameters of the 2015 Mw 8.3 Illapel earthquake

We report a facile synthesis of Ag@Au concave cuboctahedra by titrating aqueous HAuCl4into a suspension of Ag cuboctahedra in the presence of ascorbic acid (AA), NaOH, and poly(vinylpyrrolidone) (PVP) at room temperature. Initially, the Au atoms derived from the reduction of Au3+by AA are conformally deposited on the entire surface of a Ag cuboctahedron. Upon the formation of a complete Au shell, however, the subsequently formed Au atoms are preferentially deposited onto the Au{100} facets, resulting in the formation of a Ag@Au cuboctahedron with concave structures at the sites of {111} facets. The concave cuboctahedra embrace excellent SERS activity that is more than 70-fold stronger than that of the original Ag cuboctahedra at an excitation wavelength of 785 nm. The concave cuboctahedra also exhibit remarkable stability in the presence of an oxidant such as H2O2because of the protection by a complete Au shell. These two unique attributes enable in situSERS monitoring of the reduction of 4-nitrothiophenol (4-NTP) to 4-aminothiophenol (4-ATP) by NaBH4through a 4,4′-dimercaptoazobenzene (trans-DMAB) intermediate and the subsequent oxidation of 4-ATP back to trans-DMAB upon the introduction of H2O2.

This article proposes a new noncircular gear transmission mechanism with an involute–cycloid composite tooth profile to obtain the twice unequal amplitude transmission of noncircular gears. That is, the instantaneous transmission ratio has twice obvious fluctuations with unequal amplitude in a complete rotation cycle of gear transmission. The twice unequal amplitude transmission ratio curve was designed based on Fourier and polynomial functions, the change law of the Fourier coefficient on the instantaneous transmission ratio was analyzed, and the pressure angle and contact ratio of the involute–cycloid composite tooth profile was calculated. The involute–cycloid composite tooth profile noncircular gear was machined by wire cut electrical discharge machining technology, while its meshing experiment was performed using high-speed camera technology. The results demonstrate that the instantaneous transmission ratio curve value obtained via the high-speed camera experiment was consistent with the simulation value of virtual software. Furthermore, the involute–cycloid composite tooth profile was applied in the seedling pickup mechanism of noncircular gear planetary gear train. The possibility of the application of the involute–cycloid composite tooth profile in the seedling pickup mechanism was verified by comparing the consistency of the theoretical and simulated seedling picking trajectory.

This paper mainly describes the preparation of carbon nanotubes (CNTs) reinforced BMI/DBA composites, as well as the effects of CNTs contents on mechanical properties of BMI/DBA/CNTs nanocomposites. The results indicated that with the level of hydroxy-modified carbon nanotubes increased, the mechanical properties of the BMI/DBA/CNTs nanocomposites first increase then decrease. When the content of hydroxyl-modified carbon nanotubes was added to 0.75wt%, the mechanical properties of obtained nanocomposites reached the maximum. In addition, the hydroxyl-modified carbon nanotubes were found to be compatible with the polymer matrix effectively.

A novel total cervical prosthesis (TCP) for single-level cervical subtotal corpectomy was assessed in a caprine animal model.

Colloidal cadmium chalcogenide nanosheets with atomically precise thickness of a few atomic layers and size of 10–100 nm are two-dimensional (2D) quantum well materials with strong and precise quantum confinement in the thickness direction. Despite their many advantageous properties, excitons in these and other 2D metal chalcogenide materials are short-lived due to large radiative and nonradiative recombination rates, hindering their applications as light harvesting and charge separation/transport materials for solar energy conversion. We showed that these problems could be overcome in type-II CdSe/CdTe core/crown heteronanosheets (with CdTe crown laterally extending on the CdSe nanosheet core). Photoluminesence excitation measurement revealed that nearly all excitons generated in the CdSe and CdTe domains localized to the CdSe/CdTe interface to form long-lived charge transfer excitons (with electrons in the CdSe domain and hole in the CdTe domain). By ultrafast transient absorption spectroscopy, we showed that the efficient exciton localization efficiency could be attributed to ultrafast exciton localization (0.64 ± 0.07 ps), which was facilitated by large in-plane exciton mobility in these 2D materials and competed effectively with exiton trapping at the CdSe or CdTe domains. The spatial separation of electrons and holes across the CdSe/CdTe heterojunction effectively suppressed radiative and nonradiative recombination processes, leading to a long-lived charge transfer exciton state with a half-life of ∼41.7 ± 2.5 ns, ∼30 times longer than core-only CdSe nanosheets.

Aging is a primary risk factor for neurodegenerative diseases, such as Alzheimer’s disease (AD). SIRT2, an NAD+(nicotinamide adenine dinucleotide)-dependent deacetylase, accumulates in the aging brain. Here, we report that, in the amyloid precursor protein (APP)/PS1 transgenic mouse model of AD, genetic deletion of SIRT2or pharmacological inhibition of SIRT2 ameliorates cognitive impairment. We find that suppression of SIRT2 enhances acetylation of APP, which promotes non-amyloidogenic processing of APP at the cell surface, leading to increased soluble APP-α (sAPPα). We discover that lysines 132 and 134 of the major pathogenic protein β-amyloid (Aβ) precursor are acetylated and that these residues are deacetylated by SIRT2. Strikingly, exogenous expression of wild-type or an acetylation-mimic APP mutant protects cultured primary neurons from Aβ42 challenge. Our study identifies SIRT2-mediated deacetylation of APP on K132 and K134 as a regulated post-translational modification (PTM) and suggests inhibition of SIRT2 as a potential therapeutic strategy for AD.

Digital band-pass filters play a very important role in instrument design. For some special applications, such as corrosion inspection of buried oil or gas pipeline, more than one band-pass filter with different center frequencies are needed to process different frequency signals. FPGA (Field-Programmable Gate Array) are widely used in these applications because of its high compute velocity and flexibility. For low cost and high reliability purposes, it is expected that one digital filter with a fixed configuration parameters can serve as multi different center frequency digital filter. In this paper a design method is proposed to realize two different center frequency band-pass filters which have the same filtering effect. Through analysis of design process for FIR band-pass filter, it’s easy to find that if the ratios (filter’ sample rate of input data to its cut-off frequency) of two filters keep equal, the normalized frequency will also equal. Thus according to this, two band-pass filters can have the same coefficients only if they have the same ratio of sample rate to cut-off frequency. This relationship is discussed here and MATLAB experiment is used to prove its effectiveness. This method is already used to design filters in pipeline current mapper instrument to inspect pipeline corrosion.

The fixed level and dynamic denoising method was studied based on indoor-to-outdoor measured channel impulse responses (IRs) at 5.25 GHz with radio frequency (RF) 100 MHz bandwidth. It is found that the dynamic ranges, peak powers and noise floors of the IRs are with close correlations. The comparisons with different denoising methods are given by deriving the power delay profiles (PDPs), root mean square (RMS) delay spread (RMS DS), number of paths (NOPs) and Ricean K-factors. It is concluded that the traditional fixed level noise cut is under estimate of DS and NOPs. The Ricean K-factors are of little sensitive to noise cut irrespective of what kind of methods applied. The PDPs are not very sensitive to the fixed level noise cut, however, obvious changes can be found by dynamic noise cut. The dynamic noise cut is preferred when clear noise floors is observed and decided from the measured IRs, it's of importance in data post processing for wideband radio channel measurements as well as the relevant modeling work.

We investigated the effect of the donor-doped content on the positive temperature coefficient of resistivity (PTCR) of (Ba1-xSmx)TiO3 (BST) Based Ceramics that were sintered at 1300 °C for 30 min in a reducing atmosphere and re-oxidized at 850 °C for 1 h. The results indicated that the resistance jump first increased and then decreased with an increase of the donor-doped concentration. Moreover, the specimens achieved a low room temperature resistivity of 383.1 Ω·cm at a donor-doped content and exhibited a pronounced PTCR characteristics with a resistance jump of 3.1 orders of magnitude. Furthermore, the RT reisistivity of the samples reduced and increased with the increasing of the donor-dopant content in the range of 0.1−0.5 mol% Sm3+. In addition, the effect of the Sm3+-doped concentration on the grain size of the ceramics was investigated in our paper.

A novel β-diketone 4-[4-(Dibenzylamino) phenyl]-2,4-dioxobutanoic (DPD) and its corresponding Eu3+ complex with 1,10-phenanthroline were synthesized. The structure, thermal behaviour and fluorescence property of the complex was characterized by Fourier Transform Infrared (FT-IR), thermal gravimetric analysis (TGA) and fluorescence spectrophotometer. The fluorescence characterization shown that the addition of β-diketone and 1,10-phenanthroline enhance the fluorescence intensity of the complex. Eu3+ complex was considered to be a valuable organic light-emitting material with bright red fluorescence because of its strong emission band. Furthermore, the thermal stability characterizarion shows that the obtained rare earth β-diketone complexes have good thermostability.

This paper mainly describes the changes of properties of low density polyethylene and polypropylene after multiple processing. Melt flow index (MFI) analysis, thermal gravimetric analysis (TGA) ,differential scanning calorimeter (DSC) and mechanical properties measurements were used to characterize the thermal stabilities, processability, mechanical properties of virgin and recycled PE and PP. The results indicated that MFI of PE decreased with increasing the number of processing cycles whereas the opposite trend applies to PP. The thermal degradation temperature of the 6th extrudates decreased slightly in comparison with virgin ones. An amorphous region of recycled PE was observed by DSC. The mechanical properties of extruded materials were also affected due to the thermal mechanical degradation.

The technique of plasma polymerization was used in the preparation of the poly (cyanate ester) thin films using 4-methoxyphenol cyanate ester (MPCE), 4-Cumylphenol cyanate ester (CPCE) and 4-phenylphenol cyanate ester (PPCE) as precursors. Different from the conventional thermal polymerization of cyanate ester monomers, the plasma polymerization of three monomers proceeds mainly via the opening of π-bonds of the cyanate ester functional groups which are further formed into a large π-conjugated system. The dielectric properties of the resulting plasma thin films were evaluated and results show that the dielectric constant of the three polycyanurate thin films decreased with increasing frequency, while in contrast, the dielectric loss factor increased with the increasing frequency. The obtained poly (cyanate ester) thin films might be the potential new candidates to be used as intermetallic dielectrics in microelectronics.

AbstractImportant data sets of crystallographic van der Waals radii covering major portions of the Periodic Table are reviewed, including those originally published in Pauling’s pioneering work in the late 1930s, together with other more recent data sets. The van der Waals radii for rare gases are determined next from short contact distances in crystallographic data, as an illustration of the value of crystal structure databases for the direct determination of van der Waals radii for non-metallic elements. Then, van der Waals radii for the other non-metallic and metallic elements, as presented in the literature and having been determined using various approaches, are compared systematically. Finally, certain outstanding problems related to the derivation and application of van der Waals radii are discussed, and further investigations of crystallographic van der Waals radii are suggested.

The PTCR characteristics of (Ba1-xSmx)TiO3 (BSMT) with different donor-doped concentration (x) sintered in a reducing atmosphere and reoxidized in air are investigated. The results reveal that the room temperature resistivity (ρRT) of the semiconducting BSMT ceramics first decreases and then increases with increasing of the x values, especially when x is 0.004, the semiconducting BSMT ceramics reoxidized at 850oC for 1 h after sintering at 1300 °C for 30 min in a reducing atmosphere achieve a lower room temperature resisitivity of 82.6 Ωcm. in addition, the doped 0.1 mol% Sm3+ BSMT samples fired at 1300 °C for 30 min in air exhibit remarkable PTCR effect with a resistance jumping ratio of 3.4 orders magnitude; moreover, a lower ρRT of the BSMT specimens sintered in a reducing atmosphere is obtained.

According to the vulnerable erosion ability of the ordinary hydraulic concrete, we adopt the method which adding both with superfine slag and super plasticizer to form the high performance concrete.The experiment about concrete erosion was carried out between the high performance concrete and the ordinary hydraulic concrete, the corrosion mechanism was studied respectively from the macro perspective and the micro perspective.From the experiment results we can conclude that the high performance concrete can resistance the sulfate attack which with the SO42- concentration almost reached 20250 mg/L,it has better erosion resistance than the ordinary hydraulic concrete.

Positive temperature coefficient of resistivity (PTCR) effect and electrical properties of (Ban-xSmx)TiO3 (BSMT ) samples with different Ba-site/Ti-site ratio (n) and various concentration of the donor-doped Sm3+ (x) sintered in a reducing atmosphere and reoxidized in air are investigated. The results show that the room temperature resistivity (ρRT) of the semiconducting BSMT ceramics first decreases and then increases with increasing of concentration of the donor-doped Sm3+, especially when x is 0.005 mol, the ρRT of the BSMT ceramics is the lowest. Moreover, the ρRT of the Ba-excess BSMT (n = 1.01) specimens reoxidized at 800 oC for 1 h after sintering at 1270 °C for 30 min in a reducing atmosphere is lower than the Ti-excess ones (n = 0.99), in addition, the ρRT of the BSMT specimens increases with an increase of both sintering temperature and reoxidized time.

TiO2 nanotube arrays (TNAs) modified by CuO (CuO-TNAs) catalysts were prepared by an impregnating-calcinating method using the electrochemically prepared TNAs and Cu (NO3)2 as precursors and were characterized by scanning electron microscope, transmission electron microscopy, X-ray diffraction spectroscopy and UV-visible spectroscopy. The electrocatalytic properties of the CuO-TNAs samples for hydrogen evolution reaction (HER) were investigated by linear sweep curves, electrochemical impedance spectrum and current-time curves. The results showed that the electrocatalytic activity of TNAs for hydrogen evolution reaction (HER) was significantly enhanced by CuO modification, and the electrocatalytic activity of CuO-TNAs catalysts could be further promoted by visible-light illumination. The combination of visible-light irradiation with applying a controlled potential may provide new insight into enhancing the performances of the cathode for hydrogen evolution reaction.

Six kinds of materials, including two types of nanoclays, were added into drilling fluids for being substitutes of common bentonite. Swelling properties and yield of these clays were determined. Rheology, filtration property and properties at high temperature of drilling fluids prepared by the six kinds of clays respectly were also evaluated in laboratory. The results indicate that the nanobentonite modified by intercalated polymerization can improve various properties of drilling fluids. Besides, sepiolites in Xiangtan, Hunan province and in Nanyang, Henan province are also excellent materials for preparing drilling fluids.

This paper reports a finite element analysis of the axial compressive behaviour of concrete-filled steel tubular slender columns with elliptical section. A set of test data were used to verify the FE modeling. Typical curves of axial load (N) versus deflection at mid-height (um), as well as stress distributions of steel tube and concrete of the composite columns were compared and discussed. The results clearly show that the FE model is available for predicting the load-bearing capacities and the failure modes of the specimens.

A non-circular planetary gears train beating-up mechanism was proposed, the ideal kinematic curve of beating-up rockshaft was constructed and the reverse model of the pitch curve of non-circular gears was established based on the ideal kinematic curve. When the first-level non-circular gears were set as elliptical gears, the maximum swinging angle of the sley and the influence of the elliptical gears' eccentricity on the concavo-convex characteristic of the second-level non-circular gears were analyzed. Provided with a set of parameters, the pitch curves and tooth profiles of the second-level non-circular gears were determined by reverse method. The result has shown that non-circular planetary gears train beating-up mechanism can meet the requirements of beating-up process.

By employing high resolution in-situ STM, the adsorption of alkylimidazolium-based cations of EMI+, PMI+, BMI+and OMI+on Au(111) and Au(100) surfaces are investigated systematically. The cation adsorption on both Au(111) and Au(100) are composed of double rows arising from counter-facing imidazolium-based cation pairs. On Au(100), the double rows associated with the four cations show micelle-like appearance along the two √ 2 directions of the Au(100) surface lattice units. The width of the double rows varies depending on the side chain length of the cations, but is constrained by the periodicity along the √ 2 directions. Anions of BF4-, PF6-, CF3SO3-and Tf2N-do not influence the micelle-like adsorption structure. On Au(111), the double rows are formed only when the terraces are etched to several atoms wide. Most likely, the underneath Au surface experiences restructuring to accommodate the double row structure, and the worm-like orientation of the double rows is the consequence of strain release. Both the micelle-like and worm-like adsorption structures would be lifted upon cathodic potential excursions when the surfaces are driven to undergo ordinary Au(100)-hex and Au(111)-(√ 3 × 22) reconstructions. These results reveal that the ordered micelle-like structure on Au(100) and the irregular worm-like structure on Au(111) are of the same nature.

Methods of manufacturing Niobium oxide electrolytic capacitor were studied in this work. Some phenomena were found and the reasons or mechanisms were studied by using SEM(scanning electron microscope), EDS. In experiment, comparing with the type 6.3V/47μF tantalum capacitor, NbO powder were pressed to pellet as the capacitor anode, then the NbO capacitor was manufactured through the following processes: sintering, welding, anode oxidation, MnO2 decomposition and cathode coating. Its capacitance, leakage current, ESR(equivalent series resistance) and tgδ were measured and compared with that of the simily type of tantalum capacitor, and the suitable technical parameters were chosen

Lots of complexity and uncertainties are existed in drilling process. Further more, one of the possible ways to solve on-site drilling safety accidents is the early-warning through real-time monitoring. Based on the analysis of main hazards during drilling process, considering that most of the hazards are observable and controllable, by using multi agent group (MAG) technology of distributed artificial intelligence (DAI), this paper puts forward a functional schematic model with drilling hazards monitoring multi agent group, which includes real-time monitoring agent, feature extraction agent warning analysis agent, communication agent and user interaction agent. Considering the features of drilling engineering hazard monitoring, a distributed drilling safety monitoring system including the two levels, site-level and base-level, is built.

In order to express the pitch curve of non-circular gear conveniently in a uniform way, which would lessen the complexity of calculating the tooth profile of non-circular gear, the authors propose a curve fitting method of NURBS curve with the least data points based on the fitting of NURBS curve. This method is used to express the pitch curve of non-circular gear, and the specific solution model and detailed calculation procedure are presented. In addition, a method to select data points inhomogeneously and appropriately using non-uniform factor of selecting points is proposed. Two design examples are introduced to testify the validity of this expression method.

Gold deposits on Ni/TNAs and Ni/Ti were successfully prepared by displacement- reaction method. The result shows that the activity of all the catalysts for ethanol electrooxidation is improved by visible-light illumination and AuNi-40 min/TNAs exhibits the best long-time catalytic ability. The enhanced activity of the anodes catalyzing ethanol electrooxidation under illumination can be attributed to the plasmonic photocatalytic mechanism based on the excitation of Au, the assistant catalytic effects of TiO2 and/or Ni and the improving conductivity of the substrate.

In order to realize the parametric design of the conjugate cam beating-up mechanism, on the basis of the technological parameters of beating-up mechanism, ideal kinematical curves of the beating-up mechanism are builded, and the mathematical model of reverse solution for this mechanism is established. The parameters of this beating-up mechanism are obtained by reverse solution according to the kinematic requirements and the constructed ideal kinematic curves. The secondary development of UG is conducted based on VB.NET, the parametric design platform which is integrated with the functions of parametric reverse solution, motion simulation, three-dimensional modeling and virtual assembly is built. After entering the technological parameters of beating-up and essential structural parameters by users, the three-dimensional drawing of main parts such as the conjugate cam and shaft, can be obtained by this platform, also the processing data of the cam can be calculated. This platform provides a rapid approach for the parametric design of beating-up mechanism.