摘要：To investigate the characteristics of optimal fail-safe structures subjected to single and multi-member damage scenarios,we con-sider a pin-jointed cantilever truss with all members directly connected from the load point to the *** problem formu-lations are considered—minimizing the compliance with a volume constraint and minimizing the volume with stress *** these formulations produce equivalent structures for traditional truss design problems,we find that this is not always the case in the fail-safe *** solutions are developed for a three-bar truss under both problem *** is modelled as the complete removal of any one member,and a minmax problem is constructed to minimize the compliance or volume of the structure for the worst-case damage *** new analytical solutions provide much needed benchmarks for numerical fail-safe *** problems are extended to n-bar systems with damage to multiple *** show that as the structural complexity(the number of members in a system)increases,the optimum fail-safe structure tends towards a variation of the nominal two-bar design with overlapping *** these observations,we then approach the idea of full redundancy through the introduction of parallel substructures into a more complex truss *** compare our fully redundant truss design with a benchmark fail-safe solution and show that the fully redundant design has significantly better performance and with fewer ***,this suggests that fully redundant structural designs are highly efficient and have the additional benefit of only requiring the computation of the nominal solution.

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：To improve the understanding of local and regional effects of climate change,the UK government supported the development of new climate *** Met Office Hadley centre produced a sophisticated set of probabilistic projections for future *** paper discusses the design and implementation of an interactive website to deliver those projections to a broad user *** interface presents complex data sets,generates on-the-fly products and schedules jobs to an offline weather generator capable of outputting gigabytes of data in response to a single request.A robust and scalable physical architecture was delivered through significant use of open source technologies and open standards.

摘要：Electromagnetic forming is one of the high-rate forming methods that can be extensively used to form and join axisymmetric metal sheet and tube. Tendency of homogeneous radial deformation during electromagnetic compression of aluminium tube was investigated through the design optimization method based on sequential coupling numerical simulation and experiments. The results show that the tendency depends on the length ratio of tube to coil (R), which has a critical value (Rc) corresponding to the relatively homogeneous radial deformation along axial direction. The tube length relative to Rc is insensitive to the discharge voltage. When R is greater than Rc, the deformed tube presents horn shape and the shorter coil makes for local deformation. If R is less than Rc, the deformed tube presents drum shape and the longer coil contributes to larger deformation at tube end. Rc increases with coli length and could approach to 1; inversely, it could approach to 0. These results indicate the design optimization method based on the sequential coupling numerical simulation is feasible, which can be used to realize the controllable and precise deformation of metal tube.

摘要：目的确定临床医生对入住重症监护病房（ICU）的COPD急性加重期患者预后的预测与实际结果是否一致。设计前瞻性队列研究。地点英国92个ICU及3个呼吸机依赖病房。参与者832例COPD或哮喘急性加重或COPD合并哮喘患者，表现气促、呼吸衰竭或精神状态改变，年龄在45岁及以上。结局评估指标由临床医生预测的结果以及实际观察的180天存活率。结果517例患者（62％）存活到180天。临床医生预测的180天存活率却是悲观的，平均只有49％。依照临床医生的预测，1／5预后最差的存活率仅为10％，而实际存活率却是40％。来自于覆盖英国74％的ICU数据库的信息提示，参与研究和未参与研究的ICU并没有实质性差别。在同一个ICU中入选患者与未入选患者的病情相似。结论因为决定COPD或哮喘患者是否需要气管插管，入住ICU取决于临床医生对其预后的预测．因此，一些本也许会生存下来的患者却由于那些没有根据的对其预后的悲观预测，而很可能被拒绝收入ICU。

摘要：Interest in hydrogen-powered rail vehicles has gradually increased worldwide over recent decades due to the global pressure on reduction in greenhouse gas emissions,technology availability,and multiple options of power *** the past,research and development have been primarily focusing on light rail and regional trains,but the interest in hydrogen-powered freight and heavy haul trains is also *** review shows that some technical feasibility has been demonstrated from the research and experiments on proof-of-concept *** rail vehicles powered by hydrogen either are currently operating or are the subject of experimental *** paper identifies that fuel cell technology is well developed and has obvious application in providing electrical traction power,while hydrogen combustion in traditional IC engines and gas turbines is not yet well *** need for on-board energy storage is discussed along with the benefits of energy management and control systems.

摘要：A growing number of three-dimensional(3D)-print- ing processes have been applied to tissue engineering. This paper presents a state-of-the-art study of 3D-printing technologies for tissue-engineering applications, with particular focus on the development of a computer-aided scaffold design system; the direct 3D printing of functionally graded scaffolds; the modeling of selective laser sintering(SLS) and fused deposition modeling(FDM) processes; the indirect additive manufacturing of scaffolds, with both micro and macro features; the development of a bioreactor; and 3D/4D bioprinting. Technological limitations will be discussed so as to highlight the possibility of future improvements for new 3D-printing methodologies for tissue engineering.

摘要：The increasingly complex battlefield environment requests much closer connection in a team having both manned and unmanned aerial vehicles(MAVs and UAVs). This special heterogeneous team structure causes demands for effective organizational structure design solutions. Implementing adjustable autonomy in the organizational structure, the expected evaluation function is established based on the physical resource, intelligent resource, network efficiency, network vulnerability and task execution reliability. According to the above constraints, together with interaction latency, decision-making information processing capacity, and decision-making latency, we aim to find a preferential organizational structure. The proposed organizational structure includes cooperative relationships, supervisory control relationships, and decision-making authorization relationships. In addition,by considering the influence on the intelligent support capabilities and the task execution reliability created by adjustable autonomy, it helps to build the proposed organizational structure designed with certain degree of flexibility to deal with the potential changes in the unpredictable battlefield environment. Simulation is conducted to confirm our design to be valid. And the method is still valid under different battlefield environments and interventions.

摘要：Extrusion-based cell deposition has become a prominent technique for expanding bioprinting ***,the associated print resolution in the order of nanolitre or above has been a limiting *** demand for improving print resolution towards the scale of a single cell has driven the development of precision nozzle extrusion,although the benefits gained remain ***,aided by in situ imaging,we investigated the dynamics of cell organisation through an extrusion-based microcapillary tip with picolitre precision through in-air or immersion *** microcapillary extrusion setup,termed‘Picodis’,was demonstrated by generating droplets of colouring inks immersed in an immiscible ***,using 3T3 fibroblast cells as an experimental model,we demonstrated the deposition of cell suspension,and pre-aggregated cell ***,the dynamic organisation of cells within the microcapillary tip was described,along with cell ejection and deposition upon exiting the tip *** vision-assisted approach revealed that when dispersed in a culture medium,the movements of cells were distinctive based on the flow profiles and were purely driven by laminar fluid flow within a narrow *** primary process limitations were cell sedimentation,aggregation and compaction,along with trapped air *** use of picolitre-level resolution microcapillary extrusion,although it provides some level of control for a small number of cells,does not necessarily offer a reliable method when a specified number of cells are *** study provides insights into the process limitations of high-resolution cell ink extrusion,which may be useful for optimising biofabrication processes of cell-laden constructs for biomedical research.

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。