铝合金激光双光点焊接工艺特性

对铝合金薄板激光单光点和双光点焊接(包括不填丝和填丝)的焊缝成形、对接间隙和准直度容许裕度以及气孔状况进行了比较,并分析了双光点能量分布的激光对铝合金焊接的影响.结果表明,与激光单光点焊接相比,激光双光点焊接铝合金所得焊缝表面质量更好,焊缝熔宽更大,对接间隙和准直度容许裕度明显放宽.激光双光点焊接铝合金可以显著减少焊缝中大气孔的数量,但对焊缝中小气孔数量的影响不明显.此外,填加焊丝可以进一步改善焊缝表面质量并放宽对接间隙和准直度容许裕度,但将增大焊缝产生大气孔的倾向,采用激光双光点焊接仍可使焊缝中大气孔的数量明显减少.     

FROZEN STORAGE QUALITY CHANGES IN WHOLE JONAH CRABS

The Jonah crab is an underutilized species in the mid-Atlantic region, and use of the whole, frozen crab would broaden marketing options for this seafood product. We monitored quality changes in whole cooked crabs held in a blast freezer for up to 50 weeks. A sensory evaluation panel determined the point at which detectable differences appeared in the product. Microbiological testing was conducted at selected intervals to assess bacterial content. In a triangle test, frozen experimental samples of leg meat were first differentiated from frozen controls at approximately 24 weeks. No significant difference was defected in body meat for up to 33 weeks’ storage. Microbial quality was acceptable throughout the experiment.     

Automatic analysis of multiparty meetings

This paper is about the recognition and interpretation of multiparty meetings captured as audio, video and other signals. This is a challenging task since the meetings consist of spontaneous and conversational interactions between a number of participants: it is a multimodal, multiparty, multistream problem. We discuss the capture and annotation of the Augmented Multiparty Interaction (AMI) meeting corpus, the development of a meeting speech recognition system, and systems for the automatic segmentation, summarization and social processing of meetings, together with some example applications based on these systems.     

Composition and synthesis of raphide crystals and druse crystals in berries of Vitis vinifera L. cv. Cabernet Sauvignon: Ascorbic acid as precursor for both oxalic and tartaric acids as revealed by radiolabelling studies

Biomineralisation in the fleshy pericarp of berries of Vitis vinifera L. gives rise to crystals of two distinct forms, viz. raphides and druses, which are found in exocarp and endocarp cells respectively. Druses have generally been considered as crystalline aggregates of calcium oxalate. However, the organic moiety of raphide crystals has been commonly accepted as tartrate, although we have found no analytical data to support that assumption. We now present TEM and X-ray powder diffraction analysis data showing that raphide crystals of V. vinifera berries are composed of calcium oxalate monohydrate. This work also established ascorbic acid as the biosynthetic precursor of both oxalic and tartaric acids. When ascorbic acid labelled with ¹⁴C at position 1 was introduced into berries via the rachis, 21% and 52% of the added radiolabel was recovered as oxalic and tartaric acids respectively. Purified crystals from the radiolabelled grape berries contained approximately 20% of the original radioactivity, further confirming the role of ascorbic acid in oxalic acid biosynthesis. To our knowledge, this is the first evidence to be published on the formation of oxalic and tartaric acids from ascorbic acid via two distinct pathways operating within the same physiological entity (organ).     

HISTAMINE PRODUCTION BY FOOD-BORNE BACTERIAL SPECIES12

A total of 112 bacterial strains representing 38 species were tested for their potential to elicit food poisoning outbreaks via histamine formation in foods. Proteus morganii and Enterobacter aerogenes displayed a quantitative superiority in terms of histamine production on a trypticase-soy broth-histidine (TSBH) medium and a tuna fish infusion broth (TFIB). When bacteria were incubated under standardized conditions in TSBH medium, histamine accumulated to levels exceeding 50 nmoles/ml of media with a total of 23 strains, including 13 of 15 P. morganii strains, 3 of 3 E. aerogenes strains, 3 of 12 Hafnia alvei strains, 1 of 4 Providencia alcalifaciens strains, 1 of 5 Enterobacter cloacae strains, 1 of 1 Proteus rettgeri strains, and 1 of 1 Citrobacter diversus strains. However, only 8 of the 15 P. morganii strains and the 3 E. aerogenes strains were capable of generating histamine in excess of 200 nmoles/ml in the TSBH medium. Of the 23 strains capable of appreciable histamine production in TSBH medium, P. morganii and E. aerogenes were, by far, the most prolific histamine producers in TFIB. Of the organisms tested, only P. morganii and E. aerogenes would appear to have the capability of forming sufficient histamine in scombroid fish products to elicit food poisoning outbreaks.     

上海房产展的空间游戏

空间的形式是人定义的。正因为是人定义的，所以形式就有可能因为创造者或使用者的想法不同而改变。可是事实通常并非如此，我们今天所看见的所有空间形式差不多都被制式化了。所以，所谓的有理想的空间创造者穷其一生都在努力想要改变既有的形式事实，但是，事实却很困难。因此，大多数设计师过了四十不惑的年纪，碍于残酷现实的考量，不是转行或变成管理者，就是任它去了，业主想要什么就给什么了。我认识的设计师实在是没几个人像我这过了半百的老设计师，还这么自以为是地坚守自己设计的信仰侦操。我自以为自己是少数的特例，从创造来说，我应该才起步吧。     

工业数字孪生系统的概念、系统结构与运行模式

数字孪生的理念与技术最初在制造业形成,随着建模仿真与控制技术的进步,以及新一代信息技术的发展,数字孪生在城市、农业、建筑等10余领域、50多个方向快速推广,这一理念目前已成为这些领域的前沿与热点方向.在对比不同类别的数字孪生系统的关键问题、主要应用场景、关键技术和数据来源等基础上,提出了工业数字孪生系统(iDTS)的概念,总结了iDTS的典型特点,包括以人为中心、"人-机-环境"相互融合、系统高保真度和孪生模型复杂性;iD T S通过由物理层、感知层、孪生层、应用层和控制层组成的系统结构来支撑系统的运行;在此基础上,提出了一个四阶段的iDTS成熟度模型,并分别定义了以仿真为主和以控制为主的iDTS.最后,结合具体工业应用场景,分析了本地化配置的运行模式、基于"云-端"的运行模式、基于"云-边-端"的运行模式和基于分布式计算的运行模式4种iDTS的运行模式,并通过典型案例描述了不同iDTS的运行模式.