世茂深坑酒店钢结构设计

系统介绍了世茂深坑酒店的钢结构设计,着重阐述了该结构的关键节点设计,对酒店钢结构框架进行了施工过程分析.结果表明:结构上端有很强的约束,刚度较大,宜选取延性较好的钢框架-支撑结构；楼板刚度对结构构件受力有显著影响,构件设计时须取不同楼板刚度计算模型下的包络结果；采用带肋钢铺板组合楼板可有效解决混凝土板受拉问题.     

Comparison of antimicrobial resistance patterns and phage types of Salmonella Typhimurium isolated from pigs,pork and humans in Belgium between 2001 and 2006

Infections with non-typhoid Salmonella represent a major problem in industrialized countries.The emergence and spread of antimicrobial-resistant pathogens, among them Salmonella, has become a serious health hazard worldwide. One of the most commonly isolated non-typhoid Salmonella serovars in pigs, pork and humans is Salmonella Typhimurium. In this study the comparison of the incidences of resistance to nine antimicrobials, resistance patterns and phage types between S. Typhimurium isolated from pigs (n = 581), pork (n = 255) and humans (n = 1870) in Belgium in the period 2001 to 2006 was performed.Resistance to the antimicrobials ampicillin, chloramphenicol, streptomycin, sulfonamides and tetracycline was frequently observed and varied between 23.5% and 83.1%. Resistance ranged from 15.6% to 20.7% for the combination trimethoprim–sulfonamides and from 3.4% to 5.8% for nalidixic acid. Resistance to the critical important antimicrobials cephalosporins and fluoroquinolones was found sporadically (≤ 1.2%). Resistance to the different antimicrobials was observed to be similar in S. Typhimurium isolates from the various origins. Twenty-seven antimicrobial resistance patterns representing in total 75.2%, 89.0% and 89.6% of the isolates from pigs, pork and humans respectively were found to be common among the three groups and 73 combinations antimicrobial resistance pattern/phage type were found to be common among pork and human isolates, representing 70.1% of the pork isolates and 51.0% of the human isolates. The high percentage of isolates that have a common resistance pattern, and in a less pronounced way a common combination phage type/resistance pattern, are in agreement with the hypothesis of transfer of antimicrobial resistant Salmonella from pigs via the consumption of pork to humans as one of the possible pathways. The most prevalent combination in Belgium within both the pork isolates (7.4%) and the human isolates (13.2%) was S. Typhimurium DT104 resistant to ampicillin, chloramphenicol, streptomycine, sulfonamides and tetracycline.     

北方寒冷地区桥面防水层施工工艺研究

结合内蒙古通辽-下洼高速公路教来河大桥桥面铺装实体工程,简要介绍了桥面防水层的施工概况,总结了涂膜类防水材料的施工工艺,为北方寒冷地区公路桥面防水层施工提供一定的参考依据。     

从美军舰队作战试验看特定辐射源识别

特定辐射源识别是提升电子侦察系统性能的关键技术之一。美军经过四十多年的研究,已建立了相关的标准体系,并通过2002年的舰队作战试验对该技术进行了针对性验证。通过分析这次试验的过程和结论,对特定辐射源识别技术的发展进行了展望。     

Comparison of different nano- and micro-focus X-ray computed tomography set-ups for the visualization of the soil microstructure and soil organic matter

This study explores the potential of different X-ray computed tomography (X-ray CT) set-ups for the discrimination of soil mineral matter, soil organic matter (OM) and the pore phase. Different X-ray sources, detectors and filtering methods were investigated. Use of a low-energy detector as well as a Cu-filter decreased the potential for phase segmentation in X-ray CT images of an artificial sand–OM mixture. A mid-range X-ray detector showed to hold more potential. Results obtained for an artificial sand–OM sample showed that an attenuation coefficient (AC) grey-value histogram-based single threshold was unsuitable for automated phase segmentation. A dual thresholding approach enabled a better separation of the different phases. Secondly, the minimal measurable pore size class in a clay loam soil aggregate was compared using micro-focus and state-of-the-art nano-focus X-ray CT. The resolution of the scanned images depends on the spot size of the X-ray source, the resolution of the detector and the magnification used. Reliable discrimination of pore and solid phases was expected to be limited by the X-ray tube's focal spot size to 2.5 μm, in contrast to the voxel size of 0.84 μm actually obtained using nano-focus CT. Although this study was limited in its extent, indications were found that more fine porosity is visible at higher resolutions and that large connected pore spaces may be observed. This fine porosity seems to be very locally autocorrelated. Further fundamental research into AC grey-value automated segmentation of OM from the mineral and pore phases, as well as the truly achievable minimal pore size class using artificial calibration samples, is necessary.     

固相萃取-流动注射化学发光法测定猪肉中盐酸克伦特罗

在碱性条件下,鲁米诺与铁氰化钾产生化学发光,盐酸克伦特罗能抑制该发光强度,猪肉样品中的盐酸克伦特罗用乙酸乙酯提取,用固相萃取柱预分离和净化,结合流动注射技术和化学发光检测,建立固相萃取-流动注射化学发光法测定猪肉中盐酸克伦特罗的检测方法。结果表明:采用所建立的方法测定盐酸克伦特罗快速、灵敏;方法检出限为0.026μg/mL,线性范围为0.05～1.0μg/mL,相对标准偏差为1.16%(n=8),用于测定肉样品中的盐酸克伦特罗,平均回收率为91.96%,测定结果与气质联用和高效液相色谱法测定结果相当。     

Assessment of human exposure to 3rd generation cephalosporin resistant E. coli (CREC) through consumption of broiler meat in Belgium

Acquired resistance of Escherichia coli to 3rd generation cephalosporin antimicrobials is a relevant issue in intensive broiler farming. In Belgium, about 35% of the E. coli strains isolated from live broilers are resistant to 3rd generation cephalosporins while over 60% of the broilers are found to be carrier of these 3rd generation cephalosporin resistant E. coli (CREC) after selective isolation. A model aimed at estimating the exposure of the consumer to CREC by consumption of broiler meat was elaborated. This model consists of different modules that simulate the farm to fork chain starting from primary production, over slaughter, processing and distribution to storage, preparation and consumption of broiler meat. Input data were obtained from the Belgian Food Safety agencies' annual monitoring plan and results from dedicated research programs or surveys. The outcome of the model using the available baseline data estimates that the probability of exposure to 1000 colony forming units (cfu) of CREC or more during consumption of a meal containing chicken meat is ca. 1.5%, the majority of exposure being caused by cross contamination in the kitchen. The proportion of CREC (within the total number of E. coli) at primary production and the overall contamination of broiler carcasses or broiler parts with E. coli are dominant factors in the consumer exposure to CREC. The risk of this exposure for human health cannot be estimated at this stage given a lack of understanding of the factors influencing the transfer of cephalosporin antimicrobial resistance genes from these E. coli to the human intestinal bacteria and data on the further consequences of the presence of CREC on human health.     

Evaluation of the ISO 10273:2003 method for the isolation of human pathogenic Yersinia enterocolitica from pig carcasses and minced meat

Pig carcass swabs (n = 254) and minced meat samples (n = 82) were examined for pathogenic Yersinia enterocolitica using different routinely used enrichment protocols. All samples were obtained in the context of the official Yersinia monitoring program in Belgium. In total, 28 carcasses (11.0%) were contaminated with Y. enterocolitica bioserotype 4/O:3 and one (0.4%) with bioserotype 2/O:9. Four minced meat samples (4.9%) tested positive for Y. enterocolitica bioserotype 4/O:3. Using the ISO 10273:2003 method, eight out of the 29 Yersinia-positive carcasses (27.6%) and none of the contaminated minced meat samples (0.0%) were detected. Reducing the enrichment time in PSB from 5 to 2 days increased the number of positive samples. Overall, enrichment in PSB at 25 °C recovered more positive carcasses and minced meat samples than selective enrichment and cold enrichment. As the exclusive use of the ISO 10273:2003 method results in a strong underestimation of Y. enterocolitica positive carcasses and minced meats, efforts are needed to optimize the current version of the ISO method. In addition, isolation of pathogenic Y. enterocolitica requires experience and the use of a stereomicroscope to avoid false negative results.