摘要：In many circumstances,dissimilar metals have to be bonded together and the resulting joint interfaces must typically sustain mechanical and/or electrical forces without failure,which is not possible by fusion welding *** melting points of magnesium(Mg)and copper(Cu)have a significant difference(nearly 400℃)and this may lead to a large difference in the microstructure and joint performance of Mg-Cu ***,diffusion bonding can be used to join these alloys without much *** work analyses the effect of parameters on diffusion layer thickness,hardness and strength of magnesium-copper dissimilar *** experiments were conducted using three-factor,five-level,central composite rotatable design *** relationships were developed to predict diffusion layer thickness,hardness and strength using response surface *** is found that bonding temperature has predominant effect on bond *** fabricated at a bonding temperature of 450℃, bonding pressure of 12 MPa and bonding time of 30 min exhibited maximum shear strength and bonding strength of 66 and 81 MPa, respectively.

摘要：磨擦搅动(FSW ) 焊接是一种创新稳固的州的加入技术并且在太空，栏杆，为加入铝的汽车、海洋的工业，镁，锌和铜被采用了合金。FSW 过程参数象工具那样旋转速度，焊接速度，轴的力量，在决定焊接质量起一个主要作用。二个方法，反应表面方法论和人工的神经网络被用来预言磨擦的张力的强度搅动焊接 AA7039 铝合金。实验基于三个因素被进行，三水平、中央的合成的脸与完整的复制技术集中了设计，并且数学模型被开发。敏感分析被执行识别批评参数。通过反应表面方法论获得的结果与通过人工的神经网络的那些相比。

摘要：This paper presents the first application of the bees algorithm to the optimisation of parameters of a two-dimensional （2D） recursive digital filter. The algorithm employs a search technique inspired by the foraging behaviour of honey bees. The results obtained show clear improvement compared to those produced by the widely adopted genetic algorithm （GA）.

摘要：A novel method was proposed to design the structure of a bone tissue engineering scafold based on triply periodic minimal *** this method,reverse engineering software was used to reconstruct the surface from point cloud *** method overcomes the limitations of commercially available software packages that prevent them from generating models with complex surfaces used for bone tissue engineering ***,the fluid feld of the scafolds was simulated through a numerical method based on fnite volume and the cell proliferation performance was evaluated via an in vitro *** cell proliferation and the mass flow evaluated in a bioreactor further verifed the flow feld simulated using computational fluid *** result of this study illustrates that the pressure value drops rapidly from 0.103 Pa to 0.011 Pa in the y-axis direction and the mass flow is unevenly distributed in the *** mass flow in the side outlets is observed to be approximately 24.3 times higher thanthe ***,although the mean value of wall shear stress is signifcantly more than 0.05 Pa,there is stil a large area with a suitable shear stress below 0.05 Pa where most cells can proliferate *** result shows that th inlet velocity 0.0075 m/s is suitable for cell proliferation in the *** study provides an insight into the design analysis,and in vitro experiment of a bone tissue engineering scafold.

摘要：The dynamic parameters of a roller rig vary as the adhesion level *** change in dynamics parameters needs to be analysed to estimate the adhesion *** of these parameters is noise emanating from wheel–rail *** previous wheel–rail noise analysis has been conducted to mitigate those ***,in this paper,the noise is analysed to estimate the adhesion condition at the wheel–rail contact interface in combination with the other methodologies applied for this *** adhesion level changes with changes in operational and environmental *** accurately estimate the adhesion level,the influence of those factors is included in this *** testing and verification of the methodology required an accurate test prototype of the roller *** general,such testing and verification involve complex experimental works required by the intricate nature of the adhesion process and the integration of the different subsystems(***,traction,braking).To this end,a new reduced-scale roller rig is developed to study the adhesion between wheel and rail roller *** various stages involved in the development of such a complex mechatronics system are described in this ***,the proposed brake control system was validated using the test rig under various adhesion *** results indicate that the proposed brake controller has achieved a shorter stopping distance as compared to the conventional brake controller,and the brake control algorithm was able to maintain the operational condition even at the abrupt changes in adhesion condition.

摘要：Introduction 3D bioprinting offers a unique biofabrication platform that allows the generation of functional tissue constructs in a spatially/geometrically controlled and automated manner using a 3 D printer and *** serves as the carrier medium that provides the ideal physico-mechanical characteristics for printability,shape fidelity,and support;and a biological microenvironment for the living cells prior to,during.

摘要：Three-dimensional printing technologies exhibit tremendous potential in the advancing fields of tissue engineering and regenerative medicine due to the precise spatial control over depositing the *** their widespread utilization and numerous advantages,the development of suitable novel biomaterials for extrusion-based 3D printing of scaffolds that support cell attachment,proliferation,and vascularization remains a ***-material composite hydrogels present incredible potential in this ***,in this work,a multi-material composite hydrogel with a promising formulation of chitosan/gelatin functionalized with egg white was developed,which provides good printability and shape *** addition,a series of comparative analyses of different crosslinking agents and processes based on tripolyphosphate(TPP),genipin(GP),and glutaraldehyde(GTA)were investigated and compared to select the ideal crosslinking strategy to enhance the physicochemical and biological properties of the fabricated *** of the results indicate that the composite hydrogel and the resulting scaffolds utilizing TPP crosslinking have great potential in tissue engineering,especially for supporting neo-vessel growth into the scaffold and promoting angiogenesis within engineered tissues.

摘要：Thixoforming is a processing method that deforms metal in a semisolid *** advantages of this process include the production of parts with good surface finish,fine microstructures and superior mechanical ***,the process mostly produces parts from aluminium cast grades,thereby not fully utilising the true potential of this ***,thermodynamic modelling can be used to formulate alloy compositions that favour this processing ***,the effects of reducing copper content and increasing silicon and magnesium contents on the thixoformability of aluminium alloy 2014 were *** work consists of both the modelling and experimental *** showed that by increasing Si and decreasing Cu content in the alloy,the solidification interval temperature was decreased and the temperature working window between the stipulated liquid fractions was widened,two of the characteristics favouring the process.A high solid-solution temperature employed resulted in the dissolution of unfavourable Mg2Si *** increase in Mg content used also resulted in the formation of the compactπ-Al8FeMg3Si6 phase and the decrease in the amount of the sharp and plate-like structure of theβ-Al5FeSi phase,improving the strength of the modified *** T6 heat treatment successfully further increased the strength of the modified alloy.

摘要：以需求受价格和广告投入影响的报童问题为研究对象,需求函数采用混合形式,研究了一类随机需求下易逝品最优定价、订货量和广告投入联合确定的报童问题。建立了需求受价格和广告投入影响的报童问题的数学模型,求解得出最优定价、广告投入和订货量。并与需求仅受价格影响的报童问题做了比较,最后给出算例说明了所得的结论。

摘要：Among the different bioprinting techniques,the drop-on-demand(DOD)jetting-based bioprinting approach facilitates contactless deposition of pico/nanoliter droplets ofmaterials and cells for optimal cell–matrix and cell–cell *** bioinks play a critical role in the bioprinting process,there is a poor understanding of the influence of bioink properties on printing performance(such as filament elongation,formation of satellite droplets,and droplet splashing)and cell health(cell viability and proliferation)during the DOD jetting-based bioprinting *** inert polyvinylpyrrolidone(PVP360,molecular weight=360 kDa)polymerwas used in this study to manipulate the physical properties of the bioinks and investigate the influence of bioink properties on printing performance and cell *** experimental results showed that a higher bioink viscoelasticity helps to stabilize droplet filaments before rupturing from the nozzle *** highly stretched droplet filament resulted in the formation of highly aligned“satellite droplets,”which minimized the displacement of the satellite droplets away from the predefined ***,a significant increase in the bioink viscosity facilitated droplet deposition on the wetted substrate surface in the absence of splashing and significantly improved the accuracy of the deposited main *** analysis showed that cell-laden bioinks with higher viscosity exhibited higher measured average cell viability(%),as the presence of polymer within the printed droplets provides an additional cushioning effect(higher energy dissipation)for the encapsulated cells during droplet impact on the substrate surface,improves the measured average cell viability even at higher droplet impact velocity and retains the proliferation capability of the printed *** the influence of bioink properties(e.g.,bioink viscoelasticity and viscosity)on printing performance and cell proliferation is important for the formulation