摘要：How to control the quality of the coatings has become a major problem during the plasma spraying. Because nozzle contour has a great influence on the characteristic of the plasma jet, two kinds of plasma torches equipped with a standard cylindrical nozzle and a converging-diverging nozzle are designed for low pressure plasma spraying（LPPS） and very low pressure plasma spraying（VLPPS）. Yttria stabilized zirconia（YSZ） coatings are obtained in the reducing pressure environment. The properties of the plasma jet without or with powder injection are analyzed by optical emission spectroscopy, and the electron temperature is calculated based on the ratio of the relative intensity of two Arlspectral lines. The results show that some of the YSZ powder can be vaporized in the low pressure enlarged plasma jet, and the long anode nozzle may improve the characteristics of the plasma jet. The coatings deposited by LPPS are mainly composed of the equiaxed grains and while the unmelted powder particles and large scalar pores appear in the coatings made by VLPPS. The long anode nozzle could improve the melting of the powders and deposition efficiency, and enhance the coatings＇ hardness. At the same time, the long anode nozzle could lead to a decrease in the overspray phenomenon. Through the comparison of the two different size＇s nozzle, the long anode is much more suitable for making the YSZ coatings.

摘要：Vehicular ad hoc networks(VANets) experiment system is ***,characteristics and research fields of VANets are introduced *** to the characteristics of VANets,key modules that multi-vehicle ad hoc experiment system needs are designed,and each module's function and practice requirement is *** reliability of experiment system is tested primarily using three experiment scenes of multi-vehicle ad hoc network,car following and wireless *** experiment result shows that multi-vehicle ad hoc experiment system has the capability of the correlated experiment of VANets.

摘要：Recently,tissue engineering (TE)is one of the fast growing research fields due the accessibility of extra-molecular matrix (ECM)at cellular and molecular level with valuable potential prospective of *** enhancement in the production of hydrogel-based cellular scaffolds with the structural composition of ECM has been accelerated with involvement of rapid prototyping ***,the recreation of ECM has been derived from naturally existed or synthetic hydrogelbased *** rapid utilization of hydrogels in TE puts forward the scope of bioprinfing for the fabrication of the functional biological tissues,cartilage,skin and artificial *** main focus of the researchers is on biofabrication of the biomaterials with maintaining the biocompatibility,biodegradability and increasing growth *** this review, biological development in the structure and cross-linking connections of natural or synthetic hydrogels are *** methods and design criteria that influence the chemical and mechanical properties and interaction of seeding cells before and after the implantations are also *** methodology of bioprinting techniques along with recent development has also been *** the end,some capabilities and shortcomings are pointed out for further development of hydrogels-based scaffolds and selection of bioprinting technology depending on their application.

摘要：An experimental study is conducted to investigate the influences of blade tip winglet on the flow field of a compressor cascade. The tests are performed in a low speed linear cascade with stationary endwall, with three blade tip configurations, including the baseline tip, the suction-side winglet tip and the pressure-side winglet tip. The fiowfield downstream of the cascade is measured using five-hole probe, from which the three-dimensional velocity field, vorticity field and pressure field are obtained. Static pressure measurements are made on the endwall above the blade row using pressure taps embedded in the plywood endwall. All measurements are made at both design and off-design conditions for tip clearance level of about 2 percent of the blade chord. The results revealed the incidence variation significantly affects the secondary flow and the associated loss field downstream of the cascade, where the tip leakage vortex and passage vortex exist as the major contributors on the field. The winglet geometry arrangements can change the trajectory of the tip leakage vortex. The suction-side winglet tip blade provides a lower overall total pressure loss coefficient when compared to the baseline tip blade and pressure-side winglet tip blade at all incidence angles.

摘要：This paper describes the design and control of a portable and lightweight knee exoskeleton for people with knee *** knee exoskeleton is designed based on our custom quasi-direct drive actuation composed of a DC motor unit and a transmission mechanism encompassing three *** online gait generation method based on gait step calculation and direct measurement using Inertial Measurement Unit(IMU)sensors is proposed to provide continuous assistance during *** on the generated gait trajectory online,Active Disturbance Rejection Control(ADRC)incorporating the feedforward compensation approach is proposed to help the human leg move in consideration of external *** developed knee exoskeleton has been employed successfully to assist impaired users with knee dysfunction to walk in a health recovery *** experimental results indicate that the online gait generation method and the proposed control method are suitable for the knee *** maximum value of the target knee angular position is approximately 50°and the mean of the control torque for the knee joint is located in the interval of[−2 Nm,4 Nm].The developed knee exoskeleton has the potential to regain normal gait to improve strength and endurance during walking in their activities of daily life.

摘要：Polyl(lactide),PLA,suffers from bitleness and low heat deflection temperature(HDT),which limits its application as an engineering *** this work,poly(L-lactide)/poly(D-lactide)/ethylene-vinyl acetate glycidyl methacrylate random copolymer(PLLA/PDL A/EVM-GMA=1/1/x)composites were prepared by melt blending,and the in situ formed EVM-g PLA copolymers improved the compatibility between PLA and ***,the blends were subjected to a two-step annealing process during compression molding,*** annealing at 120℃ to rapidly form a certain amount of stereocomplex(sc)crystallites as nucleation sites,and then annealing at 200℃ to guide the formation of new *** differential scanning calorimetry(DSC)and wide angle X-ray dffrction(WAXD)measurements confirmed the formation of highly stereocomplexed PLA *** results showed that the PLLA/PDLA blend with 20 wt%of EVM-GMA had a notched impact strength up to 65 kJ/m2 and an elongation at break of 48%,while maintaining a tensile strength of 40 ***,dynamic mechanical analysis(DMA)and heat deflection tests showed that the PLA composite had an HDT up to 142℃ which is 90℃ higher than that of normal PLA *** electron microscopy(SEM)confirmed the fine dispersion of EVM-GMA particles,which facilitated to understand the toughening ***,the highly stereocomplexed PLA composites simultaneously exhibited excellent chemical and hydrolysis ***,these fascinating properties may extend the application range of sc PLA material as an engineering bioplastic.

摘要：The low temperature,high salt content,and bacterial composition of a seawater environment can induce severe infections in open wounds,thus impeding wound *** date,numerous wound dressings have been developed for injuries and various antibacterial ***,ordinary antibacterial strategies could not provide long-term resistance to infections and could not promote wound ***,we proposed a strategy for enhancing resistance to seawater immersion wound infection by killing bacteria and delivering bacterial antigens in ***,MXene-embedded tannin-Eu^(3+)(M@TA-Eu)particles were constructed to effectively alleviate injuries infected through seawater immersion and persistently fight infection by forming in situ bacterial vaccines and immune *** the particle,the platform composed of TA and Eu3+exhibited provascularization and antigen presentation *** with near-infrared photothermal effect were introduced to kill the bacteria,promote the recruitment of antigen presentation cells,and ultimately enhance vaccination *** results showed that the particles not only effectively accelerated the healing of injuries by relieving wound inflammation and inhibiting bacteria but also produced a potent vaccination by forming in situ bacterial ***,the M@TA-Eu particles are novel materials for high-grade anti-infection dressing.

摘要：Novel applications of nanotechnology may lead to the release of engineered nanoparticles（ENPs）, which result in concerns over their potential environmental hazardous impact. It is essential for the research workers to be able to quantitatively characterise ENPs in the environment and subsequently to assist the risk assessment of the ENPs. This study hence explored the application of nanoparticle tracking system（NTA） to quantitatively describe the behaviour of the ENPs in natural sediment-water systems. The NTA allows the measurement of both particle number concentration（PNC） and particle size distribution（PSD） of the ENPs. The developed NTA method was applied to a range of gold and magnetite ENPs with a selection of surface properties. The results showed that the positively-charged ENPs interacted more strongly with the sediment than neutral and negatively-charged ENPs. It was also found that the citrate coated Au ENPs had a higher distribution percentage（53%） than 11-mercaptoundecanoic acid coated Au ENPs（20%） and citrate coated magnetite ENPs（21%）. The principles of the electrostatic interactions between hard（and soft） acids and bases（HSAB） are used to explain such behaviours; the hard base coating（i.e. citrate ions） will interact more strongly with hard acid（i.e. magnetite） than soft acid（i.e. gold）.The results indicate that NTA is a complementary method to existing approaches to characterise the fate and behaviour of ENPs in natural sediment.

摘要：The range of memory impairments associated with Alzheimer's disease(AD) has been a focus for psychological and clinical researchers for many *** addition to investigations of AD patients' veridical memory using traditional recognition memory tasks,a number of recent studies have focused on false memories to reveal the underlying causes of memory impairment in *** comparing illusory memories between AD patients and healthy older people have revealed various differences in memory deficits between the development of AD and the typical aging ***,we review 3 types of memory illusions tested in AD patients:associative memory illusions,fluency-based false memories and source memory *** comparing AD patients with healthy older adults,we sought to analyze the mechanisms underlying AD-related memory impairments at different stages of memory processing,including encoding,retrieval and *** comparison revealed that AD patients exhibit an impaired ability to establish and utilize gist representations at the encoding stage and impairments in processing on the basis of familiarity and recollection at the retrieval ***,patients with AD have access to less information when making memory *** a result,they become more susceptible to the effects of item fluency,which can be manipulated during the retrieval ***,with impaired source memory monitoring abilities,the capacity of AD patients to suppress memory illusions is *** on these findings,we propose that the study of false memories constitute a critical tool for elucidating the memory impairments involved in *** explorations of these memory impairments will have practical significance for the diagnosis and treatment of AD in the future.

摘要：A method of designing an E-plane power combiner composed of two quarter-arc bent rectangular waveguides is proposed for sub-THz and THz waves. The quarter-arc bent-waveguide power combiner has a simple geometry which is easy to design and fabricate. By HFSS codes, the physical mechanism and performance of the power combiner are analyzed, and the relationship between the output characteristics and the structure/operating parameters is given. Simulation results show that our power combiner is suitable for the combining of two equalpower and reversed-phase signals, the bandwidth of the combiner is wide and can be adjusted by the radius of the quarter-arc, and the isolation performance of the combiner can be improved by adding thin film resistive septa at the junction of two quarter-arc bent waveguides. Meanwhile, an approximate method based on the analytic geometrical analysis is given to design this power combiner for different frequency bands.