基于智舌的水产品中创伤弧菌快速检测体系的构建

以创伤弧菌为研究对象,探讨智舌在致病性弧菌快速检测中的可行性。首先用基于脉冲伏安法的智舌监测创伤弧菌的生长趋势,并以常规的浊度法验证其可行性;再用智舌鉴别11种致病性弧菌的液体培养物,以确定智舌结合主成分分析法能否将致病性弧菌区分开及其所需的最短时间;最后用智舌结合SIMCA法构建创伤弧菌的模式识别单元。结果显示,可用智舌监测液体培养基中创伤弧菌的生长情况;当在特异性培养基中培养弧菌8h后,智舌能很好地区分11种致病性弧菌;7种电极与其频率段组合下的PCA模型,对所有样本的判别准确率达到100%,说明所建模型可用于创伤弧菌的快速筛检。智舌快速检测创伤弧菌的方法切实可行。     

一种水溶性酚醛树脂在浸渍滤纸中的应用研究

本文介绍了一种水溶性酚醛树脂在滤纸增强中的应用,并对固化工艺对浸渍滤纸力学性能的影响及浸渍滤纸耐油性能进行了研究。测试结果表明,该树脂游离醛含量约为1%,对环境污染小,储存稳定性较好。滤纸经酚醛树脂处理后,力学性能较处理前有明显改善,上胶量为20%的滤纸耐破度最高可达到514kPa,抗张强度可达到8.03kN/m,断裂伸长率可达7.56%,柔韧性能良好。且浸渍滤纸表现出优异的耐油性能,浸渍滤纸浸泡汽油和柴油后耐破度保持率分别为86.2%和79.5%,应用前景将十分广阔。     

Atmospheric polycyclic aromatic hydrocarbons in north China: a winter-time study

The contamination and outflow of atmospheric polycyclic aromatic hydrocarbons (PAHs) in the Chinese Northern Plain, a region with a total area of 300 000 km2 and a high PAH emission density, were investigated. Polyurethane foam (PUF) and PM10 samples were collected at 46 sites located in urban, rural (towns or villages), and control (remote mountain) areas in the winter from November 2005 to February 2006. The observed concentrations of atmospheric PAHs were generally higher than those reported for developed countries and southern Chinese cities. It was found that there was no significant difference in air PAH concentrations between the urban and the rural areas (514 +/- 563 ng/m3 and 610 +/- 645 ng/ m3, respectively), while the PAH concentrations at the control sites (57.1 +/- 12.6 ng/m3) were 1 order of magnitude lower than those at the other sites. The primary reason for the similarity in PAH concentrations between urban and rural areas was the fact that the predominant sources of biomass and domestic coal combustion were widely spread over the study area. The partition constants (K(PM10)) of PAHs were significantly correlated to the corresponding values of subcooled liquid-vapor pressure (pL0). However, the regression slopes of log K(PM10) versus log pL0 were much steeper than -1, indicating adsorption dominated over absorption. Three distinct patterns of outflow from the study area were identified by forward trajectory and cluster analysis.     

12Cr1MoVG钢管表面折叠形成原因分析及改进

12Cr1MoVG热轧圆钢制造的钢管表面出现折叠缺陷.利用金相显微镜、扫描电镜等手段通过对钢管表面缺陷形成的原因进行分析,发现折叠缝隙内存在灰色氧化物,在折叠缝隙附近存在高温氧化质点,折叠缝隙边缘组织存在明显脱碳,并追溯热轧圆钢表面质量及铸坯表面质量.结果 表明,钢管表面存在的折叠状缺陷是热轧圆钢表面裂纹缺陷经穿管所致...     

麦草浆甲醇强化氧气漂白的研究

进行ＡＳ－ＡＱ麦草浆甲醇强化的氧气漂白研究，结果表明：漂前的硫酸预处理是提高氧漂浆质量的重要措施；在实验条件下，甲醇用量和氧气初压是决定漂浆白度的最主要因素；温度对漂浆得率的影响较大；温度太高，将对漂浆白度不利；漂白时间对漂浆白度、得率的作用较小。在选定的６％甲醇、９０℃、８０分钟、０．７ＭＰａ氧气初压的条件下，氧漂浆白度为７３．４％ＳＢＤ；再经１．５％Ｈ２Ｏ２漂白，浆白度达８２％ＳＢＤ，裂断长为     

英国线材制品工业研究

研究英国线材制品在钢铁工业中的地位,线材及其一次制品、二次制品的生产、消费、进出口现状及发展规律。研究表明:英国线材消费较低,只有钢铁总消费的7%,线材消费量只有线材产量的70%;线材出口比例较大,占产量的50%以上;线材加工比例较高,并呈上升趋势,2003年线材深加工比例达到77%;钢丝制品的表观消费大于生产量,2003年产量比表观消费低11.5%。     

Phosphorus feeding levels and critical control points on dairy farms

A viable and cost-effective approach to managing P on dairy farms is to minimize excess P in diets, which in turn leads to less excretion of P in manure without impairing animal performance. A questionnaire survey was conducted, coupled with on-site feed and fecal sample collection and analysis on dairy farms in New York, Pennsylvania, Delaware, Maryland, and Virginia. The purpose was to assess dietary P levels and to identify critical control points pertaining to P feeding management. Survey responses, 612 out of 2500 randomly selected farms, revealed a wide range of dietary P concentrations for lactating cows, from 3.6 to 7.0 g/kg of feed DM. The mean was 4.4 g/kg, which was 34% above the level recommended by the NRC for 27.9 kg milk/d, the mean milk yield in the survey. Higher P concentrations in diets were not associated with higher milk yields (n = 98, R2 = 0.057 for the survey farms; n = 92, R2 = 0.043 for farms selected for on-site sampling). However, higher dietary P led to higher P excretion in feces (n = 75, R2 = 0.429), with much of the increased fecal P being water soluble. Phosphorus concentrations in diet samples matched closely with P concentrations in formulated rations, with 67% of the feed samples deviating <10% from the formulations. On 84% of the survey farms, ration formulation was provided by professionals rather than producers themselves. Most producers were feeding more P than cows needed because it was recommended in the rations by these consultants. In conclusion, P fed to lactating cows averaged 34% above NRC recommendations; to reduce excess dietary P, ration formulation is the critical control point.     

自进式旋转射流钻头破岩效果

利用有限的排量实现高效的破岩效率并尽可能增大径向水平井眼的延伸能力是实施新型径向水平井技术的关键,射流钻头的性能是该关键技术要解决的首要问题。在多孔射流钻头的基础上,设计研制了自进式旋转射流钻头,分析了其工作原理,并通过试验对自进式单孔旋转射流钻头、自进式单孔直旋混合射流钻头、自进式多孔旋转射流钻头以及自进式多孔直旋混合射流钻头随时间、射流压力和喷距的破岩钻孔规律进行了研究。研究结果表明:当喷距范围为9~12 mm、射流压力为20~35 MPa时,在相同的射流压力和喷距条件下,自进式多孔直旋混合射流钻头的破岩效果优于自进式多孔旋转射流钻头,其中1+4孔的多孔直旋混合射流钻头的破岩效果最好。设计得到的新型射流钻头可以提高径向水平井的钻进速度。     

ZLD自动连续顶推系统在波形钢腹板PC组合梁桥施工中应用

以国内郑州市陇海路快速通道工程常庄水库段波形钢腹板PC组合梁桥首次采用顶推施工法为背景,介绍了ZLD自动连续顶推系统应用于波形钢腹板PC组合梁桥顶推的施工方案设计、相关施工工艺和关键要点,工程实践表明其同步控制、自动化程度高、施工灵活的优越性,能多点实时同步地根据墩顶水平反力、变形调整顶推力,提高了顶推工程施工的效率和安全可靠性,有着广泛的应用前景。