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Guided bone/tissue regeneration (GBR/GTR) is commonly used in dental treatment. The desired bone/tissue regeneration is achieved by placing a barrier membrane over the defect to avoid the downward growth of faster-growing connective and epithelial tissue into the defect. This review aimed to evaluate osteogenic properties, degradation characteristics, and postoperative complications of eight biodegradable membranes in animal experiments, including non-crosslinked collagen membrane (NCCM), crosslinked collagen membrane (CCM), silk membrane (SM), polylactic-co-glycolic acid, polylactic acid, polyethylene glycol hydrogel, polycaprolactone (PCL), and magnesium alloys. Seven electronic databases (PubMed, Embase, Web of Science, Cochrane Library, Science Direct, Wiley, Scopus and Google Scholar) were screened. Study selection, data extraction and quality assessment were made in duplicate. The SYRCLE assessment tool, CERQual (Confidence in the Evidence from Reviews of Qualitative Research) tool and GRADE tool were used to grade the risk of bias and level of evidence. A total of 2512 articles were found in the electronic database. Finally, 94 articles were selected, of which 53 were meta-analyzed. Surface under the cumulative ranking curve showed the best results for new bone formation in the magnesium barrier membrane group, followed by SM, PCL, NCCM, and CCM. Qualitative analysis showed good biocompatibility for natural polymer membranes and a longer degradation time for synthetic polymer membranes. In addition, 34 studies all showed high bias risks, while other studies had unclear bias risks. Natural polymer membranes were more effective for bone regeneration and magnesium alloys were proved to be promising barrier materials that warrant future research.

Double crystal monochromator is the core device of the synchrotron light source beamline, for the application of double crystal monochromator trimmer mechanism not only needs a high angular adjustment resolution, but also needs a high inherent frequency to ensure its stability. In this paper, we have analyzed the inherent frequency of an angle-trimming mechanism applied to a biocrystal monochromator by the energy method, established the relationship equation between its inherent frequency and each parameter of the mechanism, and analyzed the influence of each parameter on its inherent frequency. And we establish the simulation model according to the actual installation situation to carry out finite element analysis. The results prove that the mechanism has excellent stability performance and meets the requirements of light source use.

To solve the problem of Angle fine-tuning in the vertical direction of optical devices, we propose an Angle fine-tuning mechanism based on Bridge-type Mechanism. In this paper, we use the method of compliance matrix to establish the statics model of the mechanism and calculate the influence of each parameter on the magnification of the model, then verify it by finite element simulation. Meanwhile, we deduce the calculation formula of compensation value by simulation value and theoretical value to establish Theoretical equations of motion for this mechanism. The results indicate that the simulation results agree well with the theoretical calculation results, after introducing the compensation value, the error caused by the amplification loss of the mechanism can be compensated well to ensure the accuracy of the derived formula.

We present a class of two-dimensional memristive maps with a cosine memristor. The memristive maps do not have any fixed points, so they belong to the category of nonlinear maps with hidden attractors. The rich dynamical behaviors of these maps are studied and investigated using different numerical tools, including phase portrait, basins of attraction, bifurcation diagram, and Lyapunov exponents. The two-parameter bifurcation analysis of the memristive map is carried out to reveal the bifurcation mechanism of its dynamical behaviors. Based on our extensive simulation studies, the proposed memristive maps can produce hidden periodic, chaotic, and hyper-chaotic attractors, exhibiting extremely hidden multi-stability, namely the coexistence of infinite hidden attractors, which was rarely observed in memristive maps. Potentially, this work can be used for some real applications in secure communication, such as data and image encryptions.

This paper studies a new class of two-dimensional rational maps exhibiting self-excited and hidden attractors. The mathematical model of these maps is firstly formulated by introducing a rational term. The analysis of existence and stability of the fixed points in these maps suggests that there are four types of fixed points, i.e., no fixed point, one single fixed point, two fixed points and a line of fixed points. To investigate the complex dynamics of these rational maps with different types of fixed points, numerical analysis tools, such as time histories, phase portraits, basins of attraction, Lyapunov exponent spectrum, Lyapunov (Kaplan–Yorke) dimension and bifurcation diagrams, are employed. Our extensive numerical simulations identify both self-excited and hidden attractors, which were rarely reported in the literature. Therefore, the multi-stability of these maps, especially the hidden one, is further explored in the present work.

The ocean energy resources are abundant in China. The technical potential in Chinese coastal area is more than 70 GW. Thus, the utilization of ocean energy resources is very important for the energy saving and the mitigation of climate change. The Renewable Energy Law implemented since 2010 and the special fund program for ocean energy established in 2011 has advanced great progress of ocean energy technology research, development and demonstration in recent years in China. The ocean energy technologies in China have achieved rapid development under the support of the Ministry of Finance, the Ministry of Natural Resources, the Ministry of Science and Technology and so on. The accumulated capacity of ocean energy is in the international advanced level, but the ocean energy industry is still in early stage. The carbon emissions peak and carbon neutrality strategy put forward in China requires the transition to green energy and electricity, which also provides crucial opportunity for the development of the utilization of ocean energy resources in China. The paper introduces the status of ocean energy technology and industry in China firstly. Then the problems in the development of ocean energy are analysed. The potential of utilization of ocean energy is estimated to support the carbon emission reduction. Finally, the vision and main tasks are given.

The discharge characteristics of capacitively coupled argon plasmas driven by very high frequency discharge are studied. The mean electron temperature and electron density are calculated by using the Ar spectral lines at different values of power (20 W–70 W) and four different frequencies (13.56 MHz, 40.68 MHz, 94.92 MHz, and 100 MHz). The mean electron temperature decreases with the increase of power at a fixed frequency. The mean electron temperature varies non-linearly with frequency increasing at constant power. At 40.68 MHz, the mean electron temperature is the largest. The electron density increases with the increase of power at a fixed frequency. In the cases of driving frequencies of 94.92 MHz and 100 MHz, the obtained electron temperatures are almost the same, so are the electron densities. Particle-in-cell/Monte-Carlo collision (PIC/MCC) method developed within the Vsim 8.0 simulation package is used to simulate the electron density, the potential distribution, and the electron energy probability function (EEPF) under the experimental condition. The sheath width increases with the power increasing. The EEPF of 13.56 MHz and 40.68 MHz are both bi-Maxwellian with a large population of low-energy electrons. The EEPF of 94.92 MHz and 100 MHz are almost the same and both are nearly Maxwellian.

With the gradual use of VR technology on a global scale, it has gradually begun to be used in data multimedia teaching, involving more areas. This technology is conducive to improving teaching quality and teaching efficiency. In order to further improve the recommendation effect of digital digital media, this paper uses the design in the LDA model for digital multimedia synthesis and scheduling and decision-making. According to the data information of the feature mapping, combined with the LED model used, the user characteristic behavior of the digital media recommendation is carried out for data. Cluster analysis is used to obtain comprehensive data information of digital media user behavior, and digital media recommendation optimization is performed according to the obtained entropy weight.

Small object detection is a challenging research direction in the field of computer vision, due to the low resolution and restricted information of small objects. At present, the general detectors only use appearance features to classify and locate objects, but they are prone to failure under the interference of background noise. On the other hand, the detector based on deep neural network has excellent performance on large scale, but it is difficult to extract enough information of small objects. This paper proposes a feature enhancement network (FENet), which contains two modules. The Residual feature enhancement (RFE) module combines residual learning and sub-pixel convolution to improve the resolution of input small objects and remove image noise. The Attention Feature Pyramid (AFP) module integrates the feature pyramid and attention mechanism, which can extract context information and filter redundant context information. At the same time, considering the imbalance of the contribution of large and small objects to the loss function during the training process, a feedback-driven function is introduced to solve the problem of uneven loss under multiple scales. Experimental results show that compared with the existing small object detection methods, our method has better performance.

Based on the strong adsorption capacity of colloidal precipitate formed by hydrolysis of iron salts (FHCP), a kind of composite material of FHCP/Fe3O4 was prepared and used in the decoloration of dye wastewater. The results showed that FHCP/Fe3O4 had high decolorization efficiency for anionic dyes. FHCP/Fe3O4 was more suitable for the decolorization of anionic dyes in acidic environment. The impact order of foreign ions on the decolorization performance of FHCP/Fe3O4 was as follows, that is HCO3 - >SO4 2- >Cl-. The fitting of adsorption kinetic of anionic dyes on FHCP/Fe3O4 matched with the pseudo-second-order kinetic equation.

Silicate cement hydration product is a promising phosphorus adsorption material. In view of the strong alkali characteristics of early hardening cement paste, this study adopted acid leaching method to modify and then investigated its phosphorus recovery performance. The results showed that acid modification could weaken the strong alkali property, nevertheless, it also lowered phosphorus removal efficiency. The decline of phosphorus recovery was closely related to the depletion of calcium source. By the fit calculation, it can be determined that the adsorption kinetics of modified material on phosphorus met the pseudo-second-order model. This was consistent with the behavior of unmodified material. Additionally, XRD analysis demonstrated that the phosphorus species enriched on the surface of modified material mainly consisted of hydroxyapatite and variscite, which was different from the brushite of unmodified material. Acid modification would provide much more aluminum sites on the adsorption of phosphorous.

This study mainly explored the coordination relationship between Cu2+ and functional groups of acid black 10B, including sulfonic group, azo group, amino group, hydroxyl group and nitro group. By means of UV-vis spectrum scanning, FTIR and XPS techniques, the complex reaction process of cooper ion with dye molecule and their precipitate formed during alkali titration were analyzed. The results showed that copper ion had coordination with all the above groups, and its coordination with azo group and sulfonic group can be able to form a closed ring structure similar to chelate. The spectra characteristics of precipitate revealed that copper ions could play bridging role between amino and hydroxyl and its coordination process would be affected by the pH value of the solution.

In recent years, new preparation technologies of ultra-hydrophilic TiO2 films have emerged in an endless stream, such as spray pyrolysis, electrostatic spinning, spray printing, micro-arc oxidation, pulsed laser deposition, atomic force deposition, ion beam deposition, etc. These new preparation technologies are able to control the surface chemical composition and surface structure of the thin film more precisely and to prepare the ideal superhydrophilic TiO2 coating. Among them, the rf sputtering method has important research significance for the repair and maintenance of TiO2/SiO2 composite coating. Nano TiO2 has excellent photocatalytic activity and superhydrophilicity, making it an important material for the preparation of high self-cleaning superhydrophilic coatings. However, the application of TiO2 photocatalysis requires UV light, and there is less than 5% UV light in sunlight, so the application of TiO2 photocatalytic performance is greatly limited. In addition, the surface hydrophilicity of TiO2 under light also has great problems. Therefore, improving the surface hydrophilic durability of TiO2 has become a key research point.

In recent years, China’s electric power industry has made great progress, especially the achievements of ultra high voltage and ultra high voltage power transmission and transformation technology have attracted worldwide attention. At present, China has put into operation power transmission projects such as ±660kV yin-East DC extra-high voltage, ±800kV upward, Yunnan-Guangzhou DC extra-high voltage and 1000kV Dongnan Jindong-Jingmen AC extra-high voltage. These long-distance and large-capacity power transmission projects provide strong technical support for the realization of the national strategic goal of “west power transmission to the east and North power transmission to the south”.With the rapid industrialization and environmental deterioration, various industrial and natural pollutions deposited on the insulators of high-voltage transmission lines are becoming increasingly serious. In severe weather, such as fog, dew, drizzle and snowmelt, the external insulation strength will be greatly reduced. Therefore, it is very important and necessary to thoroughly study the pollution flasking of uHV and UHV insulators and comprehensively consider the influence of China’s complex geographical environment on their external insulation characteristics, which is one of the key issues related to the safe and stable operation of power grid.

The core of environmental pollution detection is quartz crystal microbalance and data acquisition circuit. Under certain conditions, when the quartz crystal vibration surface adsorbs other substances, the natural frequency of quartz crystal vibration changes with the size of adsorption mass, and the frequency is converted into identifiable micro-mass data through the data acquisition circuit. This project USES quartz crystal to detect environmental pollution.

A variety of excitation modes and signal readout modes of the microcantilever beam are all derived from the deformation characteristics of the cantilever beam, while in the detection of environmental pollutants, deformation of non-quality factors such as environmental vibration, wind, rain and snow will inevitably occur. If we only start from the deformation quantity, the consistency between the obtained results and the actual fouling micro-mass value is more prominent. Therefore, the structure, size, working mode and material properties of the microcantilever beam should be fully considered in simulation and design. The resonant frequency of the microcantilever beam must be large enough to prevent external vibration interference measurement and improve the SNR.

In this paper, the effect of SiO2 particles on electrical properties of superhydrophobic antiflash coatings was studied, which electrical properties include, the volume resistivity (ρv), the electrical strength (UB), relative permittivity (er), and the dielectric dissipation factor (tanδ). This kind of superhydrophobic coating uses modified SiO2 and TiO2 particles to construct micro-nano composite structures on the surface of FEVE fluorocarbon resin, and its surface has superhydrophobic characteristics. The results show that, with the addition of 5um SiO2 content, ρv of the coating showed a trend of first increasing and then decreasing. The amount of 20 nm SiO2 particles added has little effect on ρv. The content of 5um and 20 nm SiO2 has little influence on the UB of the coating. With the increase of 5um and 20 nm SiO2, er and the tangent of tanδ show an increasing trend. Compared with 5um SiO2, 20nm SiO2 has less influence on tanδ. The addition of 80nm SiO2 has obvious significantly adverse effects on the four electrical properties of the coating.

According to the detailed process of the development of the aircraft assembly tooling, a multi-level analysis of the user needs of the tooling is carried out through the concept decomposition and classification of the requirements. Firstly the specification system of the tooling requirements is established, so a clear link is constructed between the user requirements of the tooling and the system requirements. Secondly the demand transformation method based on QFD is proposed in order to the mapping model of demand transformation is constructed. Finally the description method of requirement model is established based on SysML.

Al–Cu, being a high-strength aluminium alloy, is used to prepared castings which are widely used in the automotive and aerospace industries as lightweight parts. However, corrosion is an issue. The Al–Cu alloys show improved properties when other elements are added to them. One such alloy is Al–4.5Cu–3.5Zn–0.5Mg. In order to improve the corrosion resistance and strength of this Al–4.5Cu–3.5Zn–0.5Mg cast alloy, a novel non-isothermal ageing (NIA) treatment was developed that comprised a heating stage up to 250 °C, followed by a cooling stage down to room temperature at the rate of 60 °C·h−1. Specimens were removed throughout the process and immediately quenched for morphological, mechanical, and electrochemical testing. The hardness continuously increased up to 124 HV with ageing time. The alloy exhibited optimal properties after ageing for ~340 min (with the aging temperature reaching 130 °C during the cooling stage of the NIA treatment), with a tensile strength and maximum corrosion depth of 395 MPa and 165 μm, respectively. Fine precipitates discontinuously appeared at the grain boundaries during the cooling stage. Some new fine Ω phases were precipitated in the grains, thereby narrowing the precipitation-free zone. Thus, high strength and good corrosion resistance of the alloy can be obtained via the NIA treatment. Notably, NIA treatments are less time-consuming than isothermal ageing treatments, thereby expanding the applications of high-strength cast aluminium alloys in the manufacturing industry.

In this paper, based on the key problems of super-bispecient insulation materials, a new nano-SiO2/Phenolic resin-based super-bispecient material was studied through blending process. The combination fastness between microcosmic rough structures and substrates and between microcosmic rough structures in existing technologies is not enough, and the rough structures are easy to be destroyed, which makes the prepared superamphiphobic surface not durable. Therefore, the study of superamphiphobic surfaces with wear resistance and repairability is a powerful guarantee to solve this problem.

In the early stage of this study, it was found that Polyurethane was only two ways to construct the super-hydrophobic surface. The second is to construct micro-nano structure with low surface energy materials. Specific preparation methods of superhydrophobic surfaces include heterogeneous nucleation method, plasma treatment method, etching method, sol-gel method, vapor deposition method, electrochemical method, alternating deposition method, template method, self-assembly method, solve-non-solvent method, direct film formation method, etc., and many successful examples have been achieved. The research work in this field is relatively few, and the materials involved are scattered. The research objectives are all focused on the construction of micro-nano multistage surface structures with low surface energy. At present, most of these works only test the corresponding electrical properties of superhydrophobic surfaces. In order to verify the application prospect of superhydrophobic surface in antifouling flashover, it is necessary to carry out in-depth research on its hydrophobic, fouling and discharge aspects.

The corrosion behavior of pure copper with sodium chloride deposition and without sodium chloride deposition in atmospheric environment was studied by 500h environmental corrosion test and linear polarization test in laboratory, as well as characterization of corrosion products by SEM and XRD. The results showed that pure copper displayed good corrosion resistance in inland atmospheric environment without pollution. After depositing NaCl salt to the surface of pure copper, the corrosion current density increases sharply and plenty of corrosion products is formed on the surface of the sample, consisting of CuO, Cu2O and CuSO4·H2O.

According to the testing methods, filthy degree measurement can be divided into direct detection and indirect detection. This paper reviewed the development history of impurity detection and the current status quo at home and abroad. On the basis of existing research, impurity detection technology application situation, analysis their respective advantages and disadvantages, summarized power system layout is structured and disadvantages. Impurity detection to seek new breakthroughs to integrated a variety of integrated pollution direct detection methods, build a real-time monitoring system, realize the insulator filth adherent state of timely, accurate, in order to reduce the pollution flashover accident and provide support for power grid external insulation protection.

We propose a feasible and flexible scheme to realize all-optical photon switching, router and amplifier by using a passive-active optomechanical system consisting of a passive cavity, an active cavity and a common movable membrane oscillator. Due to the cooperation between the gain effect of the active cavity and the interference effect between the probe fields, some novel phenomena arise, such as the frequency-independent perfect reflection first proposed in this paper, controllable photon routing, tunable fast and slow lights and so on. Based on the results, a photon switching of absorption-amplification and fast-slow-light transitions, and a photon router with controllable direction and intensity can be realized by adjusting relevant parameters such as the strengths of control fields and the relative phase between probe fields. Such a scheme may provide a promising platform for controllable photon transport and photonic device fabrication.

Chinese government pays more attentions to renewable energies (RE) in the context of increasing energy demand and climate change problems. As a promising RE, the utilization of marine renewable energy (MRE) is engaging in the world, including the wave energy and tidal current energy mainly. At the same time, the tidal current energy resources in China are abundant. Thus, the utilization of tidal current energy becomes an inevitable choice for China to meet the challenge of global climate change. The Renewable Energy Law (amendment) and "Twelfth Five-Year" Plan of Renewable Energy Development (2011-2015) were released in recent years in China, the tidal current energy are successfully implemented in China, including the R&D and pilot projects. After the summary of the status of tidal current energy converters in recent years in China, especially the devices being in the open sea test. The environmental impact study in China is also introduced in order to offer reference for the environmental impact assessment of tidal current power generation.

Disks originating from supernova fallback have been suggested to surround young neutron stars. Interaction between the disk and the magnetic field of the neutron star may considerably influence the evolution of the star through the so called propeller effect. There are many controversies about the efficiency of the propeller mechanism proposed in the literature. We investigate the fallback disk-involved spin-down of young pulsars. By comparing the simulated and measured results of pulsar evolution, we present some possible constraints on the propeller torques exerted by the disks on neutron stars.

Purpose. To build a correction factor dataset to improve accuracy of dose calculations for spot-scanning proton therapy with a range shifter employed. Material and method. Our synchrotron-based spot scanning proton therapy system has an energy range of 72.5–221.8 MeV. The Bragg peak chamber was used to perform the integral depth dose measurements in a water phantom with different air-gap sizes between the range shifter and the water phantom. Three typical energies of 151.0, 181.1 and 219.3 MeV and three air-gap sizes of 10, 20 and 30 cm were selected to perform the measurements. The measured data were used as the standard metrics for evaluating the accuracy of Monte Carlo simulations. The Monte Carlo platform TOPAS was used to simulate the transport of protons in the nozzle with a range shifter and the water phantom. The Monte Carlo generated dose data were used to build the dataset of dose correction factors for air gap effect. A treatment field from a multi-field treatment plan of a brain cancer case was selected to demonstrate the clinical significance of applying the dose correction factors. Result. The beam parameters in Monte Carlo simulations were finely tuned to make the simulated dose distributions match the measurements with the mean difference in the magnitude of 1.0%. The Monte Carlo generated correction factors for different beam energies and different depths in the water phantom show that for each specific beam energy the dose correction factor increases with the increase of air gap and decreases with the increase of depth in water, and larger correction factors are needed for higher beam energies. The gamma pass rate for the selected brain treatment field was improved from 80.4% to 97.8% after applying the dose correction factors. Conclusion. Applying the dose correction factor dataset for different air gaps between the range shifter and the target is a practical, low-cost solution to improve the accuracy of dose calculations for SSPT treatment plans.

By qualitative analysis method, a sufficient condition for the existence of peaked periodic wave solutions to the Broer–Kaup equation is given. Some exact explicit expressions of peaked periodic wave solutions are also presented.

A finite element method is applied to solve the two-dimensional turbulent channel flows. Based on the fractional step techniques, the momentum and the k- equations are split into convection and diffusion equations. The convection equations are solved by the second-order Taylor-Galerkin finite element method, which can overcome the spurious oscillations with minimal artificial diffusion, and the diffusion equations are solved by the fully explicit Galerkin method. Since the same order interpolation is used for the velocity, pressure and turbulent quantities, the present method is computationally efficient. The sudden expansion flow and the obstructed turbulent channel flow are studied. The results are in good agreement with experimental observations.

In this paper we report on laser diode end-pumped single longitudinal mode and optical bistability Tm,Ho:YLF lasers at room temperature. The maximal output power of single longitudinal mode can reach 106 mW by using only a 250 μm thick solid etalon. The single longitudinal mode laser can be used as a seed laser for laser lidar systems. Furthermore, for the first time, the phenomenon of low threshold optical bistability of Tm,Ho:YLF laser at room temperature is observed.

A SiGe/Si epilayer with a linear-step-graded buffer was grown by ultrahigh vacuum chemical vapor deposition technique at a relatively high growth temperature (780° C) and a relatively high growth rate. Almost linear Ge content variation was realized in the buffer layer due to the Ge segregation to the growing surface during epitaxial growth. Double crystal x-ray diffraction and Raman spectroscopy show that the upper layer is fully relaxed. However, the measured results show that the density of dislocation in the composition graded structure is much lower than that in single-step epilayer structures.

Lower hybrid current drive (LHCD) experiments have been done on the superconducting Tokamak HT-7 by using a new developed long pulse megawatt lower hybrid wave system. An LHCD efficiency of 0.5 × 1019 Am-2/W in a pulse length of several hundreds of milliseconds has been achieved. After boronization of the tokamak vacuum vessel, considerable improvements of plasma energy confinement and particle confinement during LHCD phase have been achieved by adjusting wave spectra. An energy transfer from the lower hybrid wave to plasma bulk electrons has been demonstrated experimentally. A computer simulation of the LHCD experiments by using a ray tracing code combined with a two dimensional Fokker-Planck code is in good accordance with experimental measurements and suggests an important role of plasma current profile.

Hyperglycemia, hyperlipidemia and inflammation are key risk factors for atherosclerosis and can lead to overproduction of reactive oxygen species (ROS), which plays a critical role in vascular endothelial dysfunction and subsequent progress of atherosclerosis. However, there is currently a lack of effective drugs that deal with ROS. Platinum nanoparticles (Pt-NPs) have proven to be promising antioxidant drugs in vitro and in vivo. To optimize the efficacy of Pt-NP based drugs, we synthesized and characterized the ROS scavenging properties of three kinds of small molecules that capped Pt-NPs (Pt-AMP-NPs, Pt-ATT-NPs, Pt-MI-NPs) on a blood vessel-mimicking microfluidic chip. The Pt-NPs showed superior superoxide dismutase (SOD)-like functions and can scavenge ROS and recover compromised cell-cell junctions under hyperglycemic, hyperlipidemic and proinflammatory conditions. Amongst these NPs, Pt-AMP-NPs showed the most superior antioxidant properties, suggesting its potency to serve as a novel drug to treat vascular diseases such as atherosclerosis. Our microfluidic chip, providing physiological hemodynamic conditions for the experiments, is potentially a promising tool for a wide range of biological research on the vascular system.