脊髓灰质炎病毒Ⅲ型Sabin株C抗原和D抗原的分离及特性分析

目的分离脊髓灰质炎病毒Ⅲ型Sabin株(sPVⅢ)C抗原和D抗原,并分析其部分特性。方法采用CsCl密度梯度离心法分离sPVⅢ的C抗原和D抗原,电镜观察病毒形态;SDS-PAGE检测病毒结构蛋白组成;微量BCA法检测蛋白浓度,计算每种抗原所占比例;细胞病变法检测病毒滴度。同时检测上样浓度及超离次数对C抗原纯度的影响。结果sPVⅢC抗原和D抗原在透射电镜下均呈球形,C抗原病毒颗粒密度较小,外壳大多较为松散,D抗原病毒颗粒密度较大,结构更稳固;C抗原由VP0、VP1、VP3蛋白组成,D抗原由VP1、VP2、VP3和VP4蛋白组成;C抗原和D抗原分别约占总蛋白含量的10%和90%,部分C抗原在分离前及分离过程中易产生聚集;D抗原的病毒滴度高于C抗原。降低上样浓度及进行二次超离可提高C抗原纯度。结论采用CsCl密度梯度离心法成功分离了sPVⅢ的C抗原和D抗原,C抗原滴度远低于D抗原,且部分易产生聚集,较难达到较高纯度。     

基于DSP的智能电源控制单元设计与实现

本文利用TI公司TMS320F28335芯片高效的浮点运算能力,结合片上丰富的外设,设计并实现了一种具有高可靠性的智能电源控制单元。该控制单元周期性地对各片上外设进行自检维护,完成多路负载通道控制、电压、电流的实时监控,并对故障进行指示、处理和上报,同时提供人机交互界面更新状态信息。经过验证,该控制单元工作稳定,具备良好的工程应用价值。     

屋盖结构柱顶隔震技术的研究

根据屋盖结构的特点,提出柱顶隔震技术;随之,建立串联弹簧模型理论用于初步确定隔震垫参数,再使用非线性动力时程分析法进行详细设计。算例表明,屋盖隔震技术不仅大大降低了屋盖本身的反应,也有效保护了柱和基础等下部结构,而且屋盖侧移和隔震垫变形正常,因此柱顶隔震技术应用于屋盖结构是可行的。     

Presence of Enterococcus faecalis in broiler litter and wild bird feces for bacterial source tracking

When Enterococcus faecalis is isolated from fresh feces, its host range appears to be limited to humans and birds. Although E. faecalis is found in human sewage, the extent to which the bacterium is found in broiler litter and in the feces of wild birds is unclear. These results have implications for bacterial source tracking. We determined if media designed for the isolation of fecal enterococci affected this host range, and if E. faecalis was routinely found in broiler litter and in the feces of wild birds. Of five different isolation media, none affected the isolation of E. faecalis. Enterococcus faecalis was routinely found in fresh broiler feces (522 of 1092 isolates; 48%), but rarely in broiler litter (12 of 1452 isolates; <2%). Therefore, broiler litter selects against this bacterium, and broiler litter is an unlikely environmental source of this bacterium. The presence of E. faecalis in eight wild bird species was highly variable. Unless the fecal loading rate from migratory or resident wild birds is high, water samples collected during baseflow conditions with high numbers of E. faecalis may indicate human fecal contamination.     

酸性尾矿废弃地生态修复技术进展

酸性尾矿废弃地废石含有硫化物，在雨水的淋溶作用下会产出硫酸，加剧废弃地的酸化，增加企业环保成本，而生态修复工作就是从源头上控制废弃地的酸化。根据尾矿废弃地酸化机理，结合国内外最新研究进展，分析了生态修复技术现状；概述了隔离覆盖、改良剂改良、植物修复、微生物法等多种处理方法在实践中的适应性及优缺点，并分别介绍了隔离覆盖-植物修复技术、原位改良-植物修复技术在Reden煤矿、永平铜矿的成功应用案例。针对酸性尾矿废弃地的特点，单一处理方法具有较大的局限性，需要采用联合工艺进行治理，隔离覆盖-植物修复技术、原位改良-植物修复技术因见效快、效果好、操作简单，势必成为将来研究的主要方向。     

Dynamic centrifuge tests on isolation mechanism of tunnels subjected to seismic shaking

Isolation layer is one of the countermeasures to enhance seismic safety of tunnels. Its behavior under earthquake is affected by many factors such as shape of the tunnel, stiffness of the isolation layer and the characteristics of the input motion. However, current knowledge on the effects of these parameters on the seismic behavior of isolation layer is limited to lack of experimental data. This paper focuses on the mechanism of isolation layer, especially the efficacy of input motion frequencies on the seismic behavior of a square tunnel with isolation layer around its outer surface. Dynamic centrifuge tests were carried out on model tunnels which took isolation layer as seismic countermeasure using input motion of sinusoidal waves of different frequencies. Actual records of ground motions, magnified to approximate 15 g peak acceleration, formed the basis of the excitations to verify the actual efficacy. Due to the difference between model material (aluminum alloy) and prototype material (concrete), the similar flexural deformation law and the similar axial deformation law could not be satisfied simultaneously. Given the fact that cross-sectional moments were one of the main factors that influenced the safety of tunnels under dynamic loadings, the similar flexural deformation law was accepted in model preparation. The results show that the bending strains of tunnel with isolation layer around its outer surface are lower than those of tunnel without isolation layer, which indicates that isolation layer has positive effect on moment reduction, especially at corners. Increasing of the input motion frequency decreases the dynamic cross-sectional bending moments. In addition, isolation layer has little influence on frequency contents of acceleration response of tunnel. This study has clarified the mechanism of isolation layer on shock absorption, which is proved to be an effective method to improve the safety of tunnel against earthquake.     

某教学楼底层柱顶隔震设计及地震响应分析

对某底层为架空层的教学楼进行了底层柱顶隔震设计和动力响应分析。时程分析表明:在7度(0.15g)中震下,减震系数为0.36,减震效果明显,上部结构可以降低半度设计;底层的柱子按8度(0.20g)罕遇地震作用下受到的内力进行强度设计,分析表明底层柱子具有足够的刚度和强度。     

用于整星隔振效果评价的隔振器影响系数指标研究

对整星隔振系统的隔振效果评价指标（振动传递率、隔振器振级落差、功率流等）进行分析,通过实例证明采用隔振器底端到顶端的传递率来评价隔振效果是不充分的,而采用隔振器振级落差、功率流等指标也在实际应用中存在各自的局限性。在分析隔振器影响系数的基础上,提出一种改进的隔振器影响系数指标,并采用位移导纳表达改进的隔振器影响系数。以自行设计的新型整星隔振平台为例,采用改进的隔振器影响系数指标进行隔振效果预测,结果表明：改进的隔振器影响系数指标可以更加简单直观地表现出整星隔振平台的隔振性能。     

Analysis and Design of Vibration Isolation System Using Open Trenches

Field vibration tests were carried out at a proposed site for the vibration testing room, and 2D numerical analysis using finite difference tool FLAC 5.0 was performed to suggest effective vibration isolation systems. In the analysis, the numerical model is first calibrated with respect to material properties, damping value, and boundary conditions to obtain the output comparable to the field test results. The calibrated model was further used to perform a parametric study by (1)?providing vibrating input motions from vibrating machines to be operated; (2)?using two depths of cutoff trench; and (3)?providing gravel bed, gravel bed with rubber pad, and gravel bed with rubber pad and cutoff trench to study the isolation effects. Comparing the results from the parametric studies with the human perception level of vibration, a decision on the isolation system was determined.     

5000m3大型常压低温液氨储罐检修工艺处理方法

作者以5 000m3大型低温常压液氨储罐现场实际工艺处理过程为依据,论述了大型液氨储罐检修前的工艺处理方法,并指出了各个处理步骤的注意事项或安全防护措施,为其它合成氨厂检修处理此类大型液氨储罐提供参考.