飞机钣金特征的智能三维标注技术

采用CAA对CATIA进行二次开发,建立了钣金零件的检验规划系统.通过钣金零件的检验规划系统得到特征的检验方法,并将所有特征对应的检验方法通过智能三维标注技术,标注到三维模型上.智能三维标注,即通过人机智能交互的方式,将所有的检验信息全部表示在三维图上,简单,直观,明了.     

Energy‐efficient masonry buildings

In line with the general trend to improved energy‐related properties of buildings in massive construction, many massive buildings have been designed and built in recent years, which have proactively observed and also helped to determine the specification of future building standards in Europe. According to [1], the first low‐energy house was built in Kassel in 1986 with an area‐related energy demand for hot water and heating of only 60 kWh/(m²a). The use of massive building materials with low thermal conductivity played a similarly important role in this case to the increasing use of thermal insulation materials and new building services technology using renewable energy sources. Keeping the constructional details simple to build by tradesmen in order to avoid thermal bridging and useless building mistakes was and is still an important practical requirement. With the help of examples, the article demonstrates that monolithic construction is suitable for compliance with current energy‐related requirements and how this is carried out.     

Beanspruchungsgerechte Formgebung von Umformwerkzeugen durch formgebendes Plasma‐Pulver‐Auftragschweißen

Load adjusted shaping of forming tools using build‐up PTA welding For the improvement of the mechanical‐technological properties of the forming tools (in particular medium sized component‐geometries) the build‐up plasma deposition‐welding was established as a manufacturing process. It could be proven that the thermo‐mechanical characteristics of these tools are improved by using of cobalt and nickel basis alloys. With the embedding of carbides in the cobalt basis matrix the most endangered surface regions of the tools may to be better protected and the life times significantly increase compared with the up to now with conventional materials manufactured components. With manufactured and tested segments of a transverse‐rolling tool it was possible to validate whether the won knowledge is transferable into the practice.     

Nonaqueous Sodium‐Ion Full Cells: Status,Strategies, and Prospects

With ever‐increasing efforts focused on basic research of sodium‐ion batteries (SIBs) and growing energy demand, sodium‐ion full cells (SIFCs), as unique bridging technology between sodium‐ion half‐cells (SIHCs) and commercial batteries, have attracted more and more interest and attention. To promote the development of SIFCs in a better way, it is essential to gain a systematic and profound insight into their key issues and research status. This Review mainly focuses on the interface issues, major challenges, and recent progresses in SIFCs based on diversified electrolytes (i.e., nonaqueous liquid electrolytes, quasi‐solid‐state electrolytes, and all‐solid‐state electrolytes) and summarizes the modification strategies to improve their electrochemical performance, including interface modification, cathode/anode matching, capacity ratio, electrolyte optimization, and sodium compensation. Outlooks and perspectives on the future research directions to build better SIFCs are also provided.     

Developing and Assessing Students' Entrepreneurial Skills and Mind‐Set*

A primary goal of The Pennsylvania State University's new Engineering Entrepreneurship (E‐SHIP) Minor is to build students' life skills so they can succeed within innovative, product‐focused, cross‐disciplinary teams. The E‐SHIP Minor is designed for undergraduate students majoring in engineering, business, or IST (Information Sciences and Technology) who aspire to be innovation leaders for new technology‐based products and companies. This paper outlines five E‐SHIP program components to meet this mission: the core courses for the minor, E‐SHIP competitions in which students exhibit their products and ideas, the E‐SHIP Event Series, student organizations to support out‐of‐classroom entrepreneurial interest, and team projects for local industry and Penn State researchers. Penn State's engineering entrepreneurship program is reviewed, summarizing both quantitative and qualitative assessment data to date, previewing future assessment plans, and providing a summary of lessons learned during the development and implementation of this program.     

Enhancing ductility and fatigue strength of additively manufactured metallic materials by preheating the build platform

The effect of preheating the build platform (process) on the microstructure/defect structure (structure) as well as the tensile and fatigue behaviour (property) of the laser beam powder bed fused (LB‐PBF) 316L stainless steel (SS) is investigated. Preheating the build platform to 150°C (P150) affects the thermal gradient and cooling rate resulting in the reduction of the volumetric defects (i.e., gas‐entrapped pores and lack of fusion (LoF)) as compared with the condition where the build platform is non‐preheated (NP). The ductility of P150 LB‐PBF 316L SS is improved as compared with the NP counterpart, resulting from the less volumetric defects as well as the change in the crystallographic orientation of the grains in P150 condition. In addition, preheating the build platform is found to enhance the fatigue resistance of LB‐PBF 316L SS specimens. This is associated with fewer and smaller volumetric defects in P150 specimens as compared with the NP ones.     

Nanogap Electrodes towards Solid State Single‐Molecule Transistors

With the establishment of complementary metal‐oxide‐semiconductor (CMOS)‐based integrated circuit technology, it has become more difficult to follow Moore's law to further downscale the size of electronic components. Devices based on various nanostructures were constructed to continue the trend in the minimization of electronics, and molecular devices are among the most promising candidates. Compared with other candidates, molecular devices show unique superiorities, and intensive studies on molecular devices have been carried out both experimentally and theoretically at the present time. Compared to two‐terminal molecular devices, three‐terminal devices, namely single‐molecule transistors, show unique advantages both in fundamental research and application and are considered to be an essential part of integrated circuits based on molecular devices. However, it is very difficult to construct them using the traditional microfabrication techniques directly, thus new fabrication strategies are developed. This review aims to provide an exclusive way of manufacturing solid state gated nanogap electrodes, the foundation of constructing transistors of single or a few molecules. Such single‐molecule transistors have the potential to be used to build integrated circuits.     

Rolling up MoSe2 Nanomembranes as a Sensitive Tubular Photodetector

Transition metal dichalcogenides, as a kind of 2D material, are suitable for near‐infrared to visible photodetection owing to the bandgaps ranging from 1.0 to 2.0 eV. However, limited light absorption restricts photoresponsivity due to the ultrathin thickness of 2D materials. 3D tubular structures offer a solution to solve the problem because of the light trapping effect which can enhance optical absorption. In this work, thanks to mechanical flexibility of 2D materials, self‐rolled‐up technology is applied to build up a 3D tubular structure and a tubular photodetector is realized based on the rolled‐up molybdenum diselenide microtube. The tubular device is shown to present one order higher photosensitivity compared with planar counterparts. Enhanced optical absorption arising from the multiple reflections inside the tube is the main reason for the increased photocurrent. This tubular device offers a new design for increasing the efficiency of transition metal dichalcogenide–based photodetection and could hold great potential in the field of 3D optoelectronics.     

The effect of compression of enclosed air on the cushioning properties of corrugated fibreboard

This work showed that the shock‐absorbing properties of corrugated fibreboard are dependent on the size of the cushion even when the static loading of the impacting product on the cushion is kept a constant. At least part of this phenomenon was found to be due to the effect of the air enclosed within the flutes of fibreboard cushions. During the dynamic compression of fibreboard pads there is a build‐up of air pressure within the cushion, which improves its cushioning performance. The greater ease with which air can escape smaller fibreboard cushions, leads to differences in their shock‐absorbing behaviour compared with larger cushions. Suggestions are made on how the design of fibreboard pads can be modified to increase the build‐up of air pressure within the flutes and improve the efficiency of the cushion. For comparison, expanded polyethylene foam was also examined and its shock absorbing properties were found to be largely independent of cushion size for constant static‐loading impacts. Copyright © 1999 John Wiley & Sons, Ltd.     

Advances in Hydrogels in Organoids and Organs‐on‐a‐Chip

Significant advances in materials, microscale technology, and stem cell biology have enabled the construction of 3D tissues and organs, which will ultimately lead to more effective diagnostics and therapy. Organoids and organs‐on‐a‐chip (OOC), evolved from developmental biology and bioengineering principles, have emerged as major technological breakthrough and distinct model systems to revolutionize biomedical research and drug discovery by recapitulating the key structural and functional complexity of human organs in vitro. There is growing interest in the development of functional biomaterials, especially hydrogels, for utilization in these promising systems to build more physiologically relevant 3D tissues with defined properties. The remarkable properties of defined hydrogels as proper extracellular matrix that can instruct cellular behaviors are presented. The recent trend where functional hydrogels are integrated into organoids and OOC systems for the construction of 3D tissue models is highlighted. Future opportunities and perspectives in the development of advanced hydrogels toward accelerating organoids and OOC research in biomedical applications are also discussed.     

A Learning Community of University Freshman Design,Freshman Graphics,and High School Technology Students: Description,Projects, and Assessment

A learning community was developed to enhance the teamwork and communication components of a freshman design course. The learning community was comprised of students from a freshman design course, a freshman graphics course, and a high school technology course. Design teams were formed by combining three to four students from each of these courses. These teams were required to research, design, build, and test a specified product. The high school and university students communicated only using e‐mails and Internet conferencing. This paper outlines how the learning community is implemented, describes three design projects, and presents the assessment methods. Assessment reveals that university students who participate in the learning community have a better understanding and confidence in the technical aspects of the design project than the students who do not participate in the learning community. It also reveals that high school participants display notable interest in the engineering design process.     

Combined Replenishment of miR‐34a and let‐7b by Targeted Nanoparticles Inhibits Tumor Growth in Neuroblastoma Preclinical Models

Neuroblastoma (NB) tumor substantially contributes to childhood cancer mortality. The design of novel drugs targeted to specific molecular alterations becomes mandatory, especially for high‐risk patients burdened by chemoresistant relapse. The dysregulated expression of MYCN, ALK, and LIN28B and the diminished levels of miR‐34a and let‐7b are oncogenic in NB. Due to the ability of miRNA‐mimics to recover the tumor suppression functions of miRNAs underexpressed into cancer cells, safe and efficient nanocarriers selectively targeted to NB cells and tested in clinically relevant mouse models are developed. The technology exploits the nucleic acids negative charges to build coated‐cationic liposomes, then functionalized with antibodies against GD₂ receptor. The replenishment of miR‐34a and let‐7b by NB‐targeted nanoparticles, individually and more powerfully in combination, significantly reduces cell division, proliferation, neoangiogenesis, tumor growth and burden, and induces apoptosis in orthotopic xenografts and improves mice survival in pseudometastatic models. These functional effects highlight a cooperative down‐modulation of MYCN and its down‐stream targets, ALK and LIN28B, exerted by miR‐34a and let‐7b that reactivate regulatory networks leading to a favorable therapeutic response. These findings demonstrate a promising therapeutic efficacy of miR‐34a and let‐7b combined replacement and support its clinical application as adjuvant therapy for high‐risk NB patients.     

基于逆向工程的产品交互式虚拟展示研究

在分析了逆向工程技术和虚拟现实技术的基础上,特别研究了实现产品交互式虚拟展示的方法。提出了通过逆向工程软件Geomagic处理扫描得到的产品点云,迅速建立数学模型,将模型导入3DMAX中进行渲染建立附属结构模型,用Cult3D实现产品的交互展示设计,最后在Director MX进行按钮连接并发布的虚拟展示方法。最后给出了实例,证明了此方法的合理性。     

Effect of build direction on the fracture toughness and fatigue crack growth in selective laser melted Ti‐6Al‐4 V

Experimental investigation was conducted to evaluate the fracture toughness and fatigue crack growth characteristics in selective laser‐melted titanium 6Al‐4 V materials as a follow‐on to a previous study on high cycle fatigue. For both the fracture toughness and crack growth evaluation, the compact tension specimen geometry was used. It was found that the fracture toughness was lower than what would be expected from wrought or cast product forms in the same alloy. This was attributed to the rapidly cooled, martensitic microstructure, developed in the parts. At low stress ratios, the crack growth rates were faster than in wrought titanium but became comparable at higher ratios. The fracture toughness appears to be higher when the crack is oriented perpendicular to the build layers. The difference in the average threshold and critical stress intensity values for the crack growth results for the three orientations was within the scatter of the data, so there was essentially no difference. The same was true for the empirically derived Paris Law constants. Residual stresses were likely to have overshadowed any variation in crack growth because of microstructural directionalities associated with build orientation.     

A 3D‐Structured Sustainable Solar‐Driven Steam Generator Using Super‐Black Nylon Flocking Materials

Solar‐driven evaporation is a promising way of using abundant solar energy for desalinating polluted water or seawater, which addresses the challenge of global fresh water scarcity. Cost‐effectiveness and durability are key factors for practical solar‐driven evaporation technology. The present cutting‐edge techniques mostly rely on costly and complex fabricated nanomaterials, such as metallic nanoparticles, nanotubes, nanoporous hydrogels, graphene, and graphene derivatives. Herein, a black nylon fiber (BNF) flocking board with a vertically aligned array prepared via a convenient electrostatic flocking technique is reported, presenting an extremely high solar absorbance (99.6%), a water self‐supply capability, and a unique salt self‐dissolution capability for seawater desalination. Through a carefully designed 3D structure, a plug‐in‐type BNF flocking board steam generator realizes a high evaporation rate of 2.09 kg m^?2 h^?1 under 1 kW m^?2 solar illumination, well beyond its corresponding upper limit of 1.50 kg m^?2 h^?1 (assuming 100% solar energy is being used for evaporation latent heat). With the advantages of high‐efficiency fabrication, cost‐effectiveness, high evaporation rate, and high endurance in seawater desalination, this 3D design provides a new strategy to build up an economic, sustainable, and rapid solar‐driven steam generation system.     

农产品加工业技术创新体系建设刍议

发展农产品加工业是新时期我国产业结构调整的一项重要任务，是农业可持续发展的关键措施，是增加农民收入的主要渠道。农产品加工业依赖于制造业的发展，依赖于加工技术的发展，依赖于食品科学与技术的发展，也依赖于现代农业的发展。为了实现全面建设小康社会的奋斗目标，发展农产品加工业，必须首先建设农产品加工技术创新体系。文章讨论了我国当前发展农产品加工业的必要性，农产品加工业发展存在的主要问题，提出了加快农产品加工技术创新体系建设的具体建议。     

Fracture toughness and fatigue crack growth rate properties in wire + arc additive manufactured Ti‐6Al‐4V

This paper presents an experimental investigation of the fracture and fatigue crack growth properties of Ti‐6Al‐4V produced by the Wire + Arc Additive Manufacture (WAAM®) process. First, fracture toughness was measured for two different orientations with respect to the build direction; the effect of wire oxygen content and build strategy were also evaluated in the light of microstructure examination. Second, fatigue crack growth rates were measured for fully additive manufactured samples, as well as for samples containing an interface between WAAM® and wrought materials. The latter category covers five different scenarios of crack location and orientation with respect to the interface. Fatigue crack growth rates are compared with that of the wrought or WAAM® alone conditions. Crack growth trajectory of these tests is discussed in relation to the microstructure characteristics.     

产品信息模型及其管理工具的研究与开发

以产品信息模型为出发点,基于STEP／AP建模技术,对支持产品全生命周期信息共享的产品数据集成技术进行研究,提出集成产品数据模型创建及其管理框架。其思想对于CIMS技术继续发展和产品数据技术的普及均有重要意义。     

Gmsh: A 3‐D finite element mesh generator with built‐in pre‐ and post‐processing facilities

Gmsh is an open‐source 3‐D finite element grid generator with a build‐in CAD engine and post‐processor. Its design goal is to provide a fast, light and user‐friendly meshing tool with parametric input and advanced visualization capabilities. This paper presents the overall philosophy, the main design choices and some of the original algorithms implemented in Gmsh. Copyright © 2009 John Wiley & Sons, Ltd.     

Intelligence and Internationalism: The Cold War Career of Anton Bruun

The Danish marine biologist Anton Frederik Bruun (1901–1961) is chiefly remembered as an explorer of the deep‐sea fauna and a key figure in international scientific organizations during the 1950s. As the Cold War increasingly permeated the marine sciences and it became too expensive for small states to operate deep‐sea research vessels, he became an asset to the USA's oceanographic establishment as it sought to first assess Soviet strength (in terms of research, technology and logistical capacity) and then to build up American oceanography in response. Bruun's contacts with the USSR – including a visit in 1957 – strengthened his contacts to the American military as well as American oceanographers. His enthusiasm for raising interest in the marine sciences in developing countries could also be matched to American geopolitical goals. Bruun's participation in the Scripps Institution of Oceanography's Naga expedition to the South China Sea and Gulf of Thailand captured the mutually beneficial nature of his American connections. Bruun was able to use the USA to reach distant oceans, while the USA in turn gained from Bruun's prestige as it forged connections with friendly states through science, an increasingly important arena for Cold War competition.