Search

Purpose: In this study, animal experiments and finite element simulation was used to study pronation-supination and the mechanical environment of the elbow at different stages of joint capsule healing after injury to reveal the mechanism of mechanical factors affecting the development of the elbow contracture. Methods: The injured limbs were immobilized for 2 weeks, 4 weeks, 6 weeks and 8 weeks in animal experiments. The total ROM and joint stiffness of the limbs were tested at each time point to define the differences between different groups. The internal soft tissue stress during joint capsule healing was obtained by finite element simulation. Results: In the animal experiments, compared with the no injury group, the total ROM of the injury group was decreased and the joint stiffness of the injury group was increased. The joint capsule thickness and shear modulus increased gradually in different stages of joint capsule healing. In the simulation, the internal soft tissue stress increased at different stages of joint capsule healing. The peak stress of the capsule was 8.32 MPa, 10.5 MPa, 11.4 MPa, 11.1 MPa and 12.2 MPa, respectively. The peak stress of humerus cartilage at different stages of joint capsule healing was greater than that of ulna cartilage and 1.2 times that of ulna cartilage. Conclusion: This study revealed the evolution of stress distribution in the surrounding tissue in the process of joint capsule healing and provided a theoretical basis for the rehabilitation of the elbow contracture and the design of rehabilitation aids.

For the reconstruction of the streamwise velocity field in the high‐Reynolds‐number (Reτ≈ Ο(106)) near‐neutral atmospheric surface layer (ASL), a predictive model was proposed in our work. In our model, the streamwise velocity time series at each height are predicted by the superposition of mean velocity, small‐scale turbulent signals, and large‐scale turbulent signals. All the parameters used by our model have clear physical meaning. In addition, the parameters can be directly determined by the experiment that is easy to be achieved in the ASL. The model can predict the streamwise velocity between 0.9 and 30 m in the near‐neutral ASL based only on single‐point‐measured large‐scale streamwise velocity signal. For example, mean velocity, turbulence intensity, and power spectrum of streamwise velocity can be predicted by the new model. Furthermore, the streamwise velocity time series predicted by the new model have a good correlation with the directly measured results, especially for large‐scale structures. It indicates that our model can be used to reconstruct the streamwise velocity field in the logarithmic region of the near‐neutral ASL, and our model is an important complement to the Marusic‐Mathis‐Hutchins model. A predictive model for the reconstruction of the streamwise velocity field in the near‐neutral atmospheric surface layer is proposedThe new model can predict the streamwise velocity between 0.9 and 30 m in the near‐neutral atmospheric surface layerThe model provides a potential contribution to the research of atmospheric surface layer and is an important complement to the MMH model

In this protocol, we present a modified gradient coating strategy for zinc anodes. We describe steps for synthesizing electrodes, measuring electrochemistry, and assembling and testing batteries. The protocol can be applied for broadening design ideas of functional interface coating.

Portable breath acetone sensor has great potential in diabetes diagnosis for acetone is a selective breath maker for diabetes. In this paper, we propose a multilayer semiconductor sensor for acetone gas sensing. Device is designed with stress adjustment layer, support layer, metal layer, insulator and sensing film. Simulation is performed, electrothermal and thermomechanical analyses demonstrate that this device has good performance in power consumption and thermomechanical reliability.

Cement hydration products carbonation is not only blamed for the carbonation-induced hardened cement paste or concrete cracking, also attributed to the pore water PH-value decrease, which causes the reinforcement corrosion under the existence of water and oxygen due to removal of oxide film passivating rebar surface, in hardened cement paste and concrete. Based on chemical thermodynamics, this paper presents the susceptibility of different cement hydration products to carbonation through calculating their Standard Gibbs Free Energy respectively, Gibbs free energy under temperature variation and the minimum equilibrium pressure of carbon dioxide triggering the carbonation process. The calculated results show that, under standard state (25oC, 100kpa), the minimum equilibrium pressure of carbon dioxide triggering carbonation process is significantly variable for different types of cement hydration products. For example, mono-sulfate sulfoferrite hydrates (3CaOFe2O3CaSO412H2O) is the most susceptible to carbonation, followed by mono-sulfate aluminate hydrates (3CaOAl2O3CaSO412H2O), while multi-sulfate sulfoaluminate hydrates (3CaOAl2O33CaSO432H2O) is the least vulnerable to carbonation, followed by silicate hydrates (5CaO6SiO25.5H2O). The findings in this paper are significant in understanding thermodynamic mechanism of cement hydrates carbonation and seeking the solution to prevent cement hydrates from carbonation-induced deterioration.

Trust investigation in Business-To-Customer (B2C) E-commerce is usually based on analyzing relative compositions of B2C E-commerce, and mainly focuses on direct perceived trust of consumers. But in real B2C E-commerce, recommended trust of mature consumer is an important channel to enhance trust for a new consumer. A recommended trust evaluation method in B2C E-commerce is proposed based on fuzzy analytic hierarchy process. Firstly, compositions that affect online trust in B2C electronic-commerce are analyzed comprehensively. An individual trust evaluation system is established. Furthermore, for a new consumer, using trust evaluations of multiple mature consumers that he/she is familiar with, the study adopts fuzzy analytic hierarchy process to build composite recommended trust evaluation method. Finally, the proposed recommended trust evaluation method is applied to evaluate recommended trust of real B2C online shopping. It simulates the process of trust evaluating of a new consumer and illustrates the validity of proposed recommended trust evaluation method.

A new method to fabricate metal/conducting polymer composite nanowires is presented by taking silver/polypyrrole composite nanowires as an example. A silver (I)-coordinated organogel as template was prepared firstly, and redox-polymerization of pyrrole took place on the gel fiber, giving product of silver/polypyrrole nanowires. The silver/polypyrrole nanowires were characterized by multiple techniques. This strategy could be carried out in one-step procedure at room temperature, and it proves the utility of coordinated organogels in template synthesis of polymer nanostructures.

A simple and general strategy is described for preparing network supported catalyst through a one-pot synthetic procedure using supramolecular gel as template. This procedure directly attaches ligand to support during fabricating the support. Using this strategy, supported CuBr/di-(2-picolyl)amine catalyst with U-shaped fibrillar network was prepared and used in atom transfer radical polymerization of methyl methacrylate. XPS and SEM characterization of the catalyst revealed homogeneous distribution of ligand, sufficient reactive sites, adequate mechanical strength and macroporosity. The polymerization results demonstrated high activity and reusability of such catalyst. This strategy might be extended to other supported catalysts used in column reactors.

With the development of computer operation technology and algorithms, the lumped dynamic model is more practical, and the development and application are more comprehensive. Among them, the direct coal liquefaction residual oil pyrolysis and coking technology, as a coal-to-liquid process, can increase the oil yield of the coal liquefaction process and reduce environmental pollution. The purpose of this paper is to study the experiment and algorithm of coal direct liquefaction residual oil pyrolysis and coking technology based on lumped kinetic engineering. Starting from the lumped kinetic engineering, this paper takes the direct coal liquefaction residual oil pyrolysis and coking technology as the research object. Based on the experiment of small- and medium-sized equipment, the residual oil pyrolysis and coking experiment is carried out. This paper further analyzes the components of the experimental products and explores the factors that affect the yield of residual pyrolysis oil based on the five lumped kinetic model of coking. Experimental data shows that when the pyrolysis temperature is 450°C, the content of liquefied heavy oil HS in the pyrolysis oil is 47.87%, the content of asphaltene A is 44.28%, and the content of preasphaltene PA is 7.85%; the pyrolysis temperature is 500 °C. At this time, the content of liquefied heavy oil HS in the pyrolysis oil is 54.97%, the content of asphaltene A is 40.23%, and the content of preasphaltene PA is 4.8%. It can be seen that, with the increase of pyrolysis temperature, the content of liquefied heavy oil HS increases, and the content of asphaltene A and preasphaltene PA decreases.

In this article, we study the Lax pairs of -dimensional equation: the modified generalized dispersive long wave (MGDLW) equation. Based on the well-known binary Darboux transformation, we dig out the recursion formulas of the first part of the Lax pairs. Then by further discussion and doing some revisional work, we make the recursion formulas fit for the second part of Lax pairs. At last, some solutions to the MGDLW equation are worked out by using the recursion formula.

We deal with the (2+1)-extension of classical Boussinesq system, which can reduce to several meaningful (1+1)-dimensional systems. By studying its Lax pair, we put forward invariances of Lax pair at first, then a recursion formula depending on an arbitrary function is derived. At last, some solutions of the (2+1)-extension of classical Boussinesq system are digged out by using the formula.

The brightness and height of the sodium laser guide star of adaptive optics could vary significantly due to the temporal dynamics of sodium column density and the mean height of the sodium layer. To measure these dynamics, an independent sodium Lidar is a necessity. Without such an instrument, it is almost impossible to discern the cause of the brightness variation of the laser guide star from the sodium layer's dynamics or other factors from the laser itself. For applications such as characterizing the performance of sodium laser for sodium laser guide star generation, minutes scale short term statistics of the sodium layers' abundance and height is extremely helpful for estimating the contribution of sodium layer's variation to the variation of laser guide star's brightness. In this paper, we analyzed our previous measurement of sodium layer dynamics that has been gathered in two winters, and presented the temporal variation statistics of sodium column density and mean height within a minute timescale based on our measurements.

Rechargeable aqueous Zn-ion batteries (ZIBs) are regarded as one of the most promising energy storage devices due to their intrinsic safety and the extensive stockpile of Zn. It is still challenging to prepare ultrafast flexible devices with high energy/power density and satisfactory stability. Herein, two-dimensional ultrathin vanadium pentoxide (V2O5) nanosheets grown directly on titanium (Ti) substrate (V2O5–Ti) are prepared as a novel flexible cathode with high energy density for ultrafast aqueous and flexible ZIBs. Benefiting from the merits of exposed active sites and increased electrical conductivity, our optimized V2O5–Ti cathode exhibits a remarkable discharge capacity of 503.1 mAh g−1at 100 mA g−1and long-term stability with 86% retention after over 700 cycles at 500 mA g−1in the aqueous coin cell. The charge storage mechanism of this V2O5–Ti cathode is investigated by in-situ Raman spectroscopy, ex-situ X-ray diffraction, and X-ray photoelectron spectroscopy. Remarkably, based on this flexible cathode, we designed an ultrafast and flexible quasi-solid-state zinc ion battery (f-V2O5–Ti//Zn), which can achieve the capacity of 377.5 mAh g−1and energy density of 622 Wh kg−1when charged at 4 A g−1for less than 6 min. It also exhibits the power density of 6.4 kW kg−1at an ultrahigh current density of 20 A g−1, which outperforms most previously reported aqueous/flexible ZIBs. As a result of superior performance, our ultrafast flexible quasi-solid-state ZIB is believed to be a promising candidate for flexible and wearable energy storage systems.

We first derive a Darboux transformation for a (2+1)-extension of Burgers equation. Then we consider the Lie symmetries, symmetry algebra, and symmetry reductions of the equation, and use symmetry reductions to obtain group-invariant solutions to the equation.

Porous low-dielectric constant (low-k) materials are needed for advanced technologies to improve signal propagation. Plasma treatments in interconnection fabrication have been considered to be critical steps to impact the low-kfilms’ properties. This study investigates the degradation of the porous low-kfilms by plasma exposure using several kinds of treatment conditions. Experimental results indicate that the increase in the dielectric constant and the degradation in the reliability for the plasma-treated low-kfilms were related to the decreased amount of Si-CH3bonds and the absorbed amount of H2O or OH groups within the film. Plasma treatment with pure H2gas extracts more CH3groups from the porous low-kfilm and forms a larger amount of H2O or OH groups. Although the plasma-treated low-kfilms using N2gas can suppress H2O or OH group formation, the increase in the dielectric constant is higher due to the formation of Si-N or C-N bonds. Plasma treatment using a mixture of H2/N2 gas can obtain a balance result in the dielectric constant increase and absorbed moisture uptake. Furthermore, increasing bias-voltage on the sample electrode during H2/N2 Plasma treatment can effectively suppress the degradation of the porous low-kdielectrics.

The radio frequency (RF) power effect of post-deposition O2plasma treatment on the physical, electrical, and reliability characteristics of high-kHfO2dielectric films were comprehensively investigated in this study. The experimental results indicated that increasing the RF power of post-deposition O2plasma treatment resulted in a stoichiometric HfO2film, but led to a thinner interfacial layer and the formation of new Hf-Si bonds. Additionally, the electrical performance and reliability of HfO2dielectric films were significantly impacted by the RF power of the post-deposition O2plasma treatment. As RF power is less than 30 W, the leakage current density and time-to-breakdown of the O2plasma-treated HfO2films were improved in comparison with those of the as-deposited samples. However, further increasing RF power to exceed 50 W would cause the continuous degradation in the electrical performance and reliability due to the plasma damage induced by oxygen active spices in a plasma environment. Therefore, performing a post-deposition O2plasma treatment process on the as-deposited HfO2dielectric films can effectively improve the dielectric's properties. However, the applied RF power is an essential controlling parameter, avoiding serious plasma damage occurrence.

This study compares the physical, electrical, and reliability characteristics of the high-kHfO2film that was fabricated by a single-step and a multiple-step deposition-annealed method. After annealing at 750oC, the single-step annealed HfO2has transformed into the polycrystalline phase, whereas the multi-step annealed HfO2 is found to remain in a nanocrystalline phase, revealing that a multi-step deposition-annealing method could greatly improve the thermal stability of the HfO2film with respect to the grain formation process. Additionally, the density and composition of the HfO2film are enhanced by multi-step deposition-annealing process. These changes lead to an improvement in the electrical characteristics, breakdown voltage, and reliability for the multi-step deposition-annealed HfO2film, revealing that the multi-step deposition-annealing method is a promising means for improving the thermal stability and reliability of HfO2gate stacks.