轻质外保温墙体温度与荷载作用的耦合效应试验研究

由不同物理力学性能材料组成的复合轻质外保温墙体,在多因素的作用下引起整体粉刷墙面的开裂、脱落等破坏现象。试验按照实际工程构造尺寸制作了两组六个试件,通过冷热箱、密封试件真空负压组合试验装置,按1：1相似比模拟温度、重力、风力等作用,对不同因素组合工况测试各构造层在温度与荷载共同作用下的耦合效应,给出了不同工况下保温层及饰面层各测点的温度场分布规律,整理出了耦合效应的应力变化特征相关曲线。试验成果可为研究解决外保温墙面破坏问题提供借鉴。     

农村多水源供水系统运行状态监测与诊断

为掌握农村多水源供水系统运行状态,诊断运行中存在的问题,以便及时改进,测定了宿迁市南蔡乡供水系统水量、水压和能耗,分析存在问题,提出改进意见。采用在线水位计、累积式水表、电接点压力表连续测定水源水位、供水流量和出厂水压,计算各水源供水能耗,提出并实施了降低能耗的措施;分析管网用水规律和漏水量。采用U盘式数字压力表连续监测管网运行压力,分析管网水压的区域分布和时间变化规律,提出保障供水水压、降低过高供水压力的建议。     

菊花食用价值研究

菊花不仅具有一定的观赏价值,还具有一定的保健功能和食用价值,已成为人们生活中不可缺少的一部分。就菊花的营养价值、药用价值、在烹饪中的应用等进行分析,同时提出存在的问题,并对今后的发展进行展望。     

动力学光度法测定痕量甲醛

在稀硫酸溶液中,甲醛对KClO3氧化罗丹明B褪色反应有催化作用,研究了其动力学条件,建立了测定痕量甲醛的动力学光度分析法,线性范围为0.45～4.55μg/mL,检出限为1.5×10-3g/mL,相关系数,r为0.9995.     

Fostering continuous innovation in design with an integrated knowledge management approach

In the global competition, companies are propelled by an immense pressure to innovate. The trend to produce more new knowledge-intensive products or services and the rapid progress of information technologies arouse huge interest on knowledge management for innovation. However the strategy of knowledge management is not widely adopted for innovation in industries due to a lack of an effective approach of their integration. This study aims to help the designers to innovate more efficiently based on an integrated approach of knowledge management. Based on this integrated approach, a prototype of distributed knowledge management system for innovation is developed. An industrial application is presented and its initial results indicate the applicability of the approach and the prototype in practice.     

15CrMo钢的高温时效性能的变化规律及计算模型

根据现有标准DL/T 787-2001提供的数据分析了随温度和球化等级的改变,15CrMo钢的碳化物相中钼元素含量、抗拉强度、屈服强度、伸长率、断面收缩率以及硬度的变化规律,同时建立了相关计算模型,并且预测出球化等级为1.5,2.5,3.5和4.5级所对应的性能参数值.此外还分别给出了依据常温抗拉强度、屈服强度、布氏硬...     

基于模型的构件软件修改影响分析

基于构件的软件构建方法目前被广泛使用在软件开发中,用于减少软件开发的工程成本和加快软件开发进度.面向构件的系统主要由第三方提供的可重用构件或者内建的可重用构件组成,因此,系统的质量好坏和维护的难易程度依赖于构件的品质.一个软件修改会给其他构件甚至整个系统带来影响,而修改影响分析是控制和消除这类影响的有效手段.然而,现有的研究很少涉及构件软件的修改影响分析,尤其缺少对系统层面的修改影响分析研究.提出了一种基于模型的系统化修改影响分析方法,该方法的基本思路是:首先提出构件及系统层面的修改影响分析模型,然后根据分析模型分别从构件和系统两个层面对构件软件修改前后的版本进行修改识别,并且利用“防火墙”方法进行影响分析.理论分析和实验结果表明,该方法是可行的,也是有效的.     

ZnO hierarchical structures synthesized via hydrothermal method and their photoluminescence properties

The controlled synthesis of ZnO hierarchical structures has been successfully realized in a large scale via a simple hydrothermal method. It was demonstrated that the morphology of the final products was simply tuned by adding different amounts of soluble salt. ZnO microparticles were prepared when no soluble salt was added, whereas microspheres and nanoflowers were selectively prepared in the presence of different amounts of NaF. ZnO nanosheets were obtained when adding appropriate amount of NaCl, Na₂SO₄, or K₂SO₄. ZnO nanobelts were obtained in the presence of appropriate amount of sodium citrate (C₆H₅Na₃O₇). The photoluminescence (PL) properties of those products were researched, and the origin of the PL was discussed.     

Occurrence and characteristics of Vibrio vulnificus in retail marine shrimp in China

Vibrio vulnificus is a gram-negative bacterium that naturally occurs in estuarine waters and marine environment. Consumption of seafood contaminated with V. vulnificus or exposure to the contaminated water causes septicemia, gastroenteritis or wound infections in humans. This study aimed at identifying the prevalence of V. vulnificus in shrimps in Chinese seafood market. From June to September 2009, 239 samples encompassing six shrimp species were collected from ten cities in China. To quantify the prevalence and the levels of V. vulnificus in shrimps, the most probable number (MPN) method was used combining with the polymerase chain reaction (PCR) which was used to classify the isolates by detecting V. vulnificus hemolysin gene (vvhA). One hundred and forty out of 239 samples were positive for V. vulnificus, with the geometric mean level at 153.3 MPN/g. The prevalence and levels of V. vulnificus in shrimps varied in different geographic areas, with the values for the samples in the South cities (179.6 MPN/g) remarkably higher than that in the North cities (7.6 MPN/g). In addition, we found that 61.7% (79/128) of the V. vulnificus positive samples contained C-type (Clinical) strains and 8 contained E-type (Environmental) strains. The antimicrobial susceptibility of the isolates to 12 antibiotics was tested as well. Most of the 169 isolates remained susceptible to the majority of antimicrobials tested, whereas some strains tend to be less sensitive to amikacin, ampicillin, tetracycline and gentamicin. In conclusion, V. vulnificus is commonly found in retail marine shrimp in Chinese seafood market, and most of the shrimp samples contained C-type strains, which may pose a potential threat to human health.     

Effects of sustained axial load and cooling phase on post-fire behaviour of reinforced concrete stub columns

In this paper is presented an experimental investigation of the effects of preload and cooling phase on the residual strength, stiffness and ductility of reinforced concrete stub columns which were heated and cooled down to room temperature under sustained axial load. Reinforced concrete stub columns were axially loaded and heated to designed temperatures in a specially built electrical furnace. After the specimens cooled down to ambient temperature with the axial loads kept constant, the stub columns were loaded to failure. The sustained preload led to significant residual deformations of reinforced concrete stub columns during the cooling phase. The test results showed that the mechanical behaviour of the fire-damaged reinforced concrete stub columns with preload was remarkably different from those without preload. The sustained axial loads resulted in obviously increased strength and stiffness during the loading phase, but reduced stiffness and deteriorated ductility in the unloading phase. Based on the test results, it is recommended that the effects of sustained axial loads during the fire and cooling phase should be taken into consideration in assessing the fire-damaged reinforced concrete columns.