The Feasibility of Immobilization of Bioflocculant-producing Bacteria Using Mycelial Pellets as Biomass Carriers

Bioflocculant-producing bacteria Agrobacterium tumefaciens F2 and Bacillus sphaeicus F6 were immobilized onto mycelial pellets to investigate the bioflocculant-producing potential of this combined organism and the corresponding flocculating efficiency. The atomic force microscope (AFM) images of mycelial surface indicate that the mycelia pellet can immobilize bioflocculant-producing bacteria F2 and F6 as a biomass carrier. The flocculating efficiency of bioflocculant produced by this combined organism was studied under the optimum flocculating conditions obtained by Response Surface Methodology (RSM). The fermentation yield of the combined mycelial pellet is about 2.6 g/L, which is higher than that of the free bacteria (only 2.2 g/L). Flocculating efficiency of the combined mycelial pellet was comparable with that of bioflocculant generated by the free bacteria. The bioflocculant yield is enhanced and the flocculating efficiency of the co-culture is uninfluenced after immobilized with mycelial pellet as a carrier. In conclusion, the mycelial pellet is feasible as a biomass carrier for the immobilization of bioflocculant-producing bacteria.     

Research on Comparison and Evaluation Studies of Several Smoothing Denoising Method Based on γ-ray Spectrum Detector

The extraction of spectral parameters is very difficult because of the limited energy resolution for NaI(TI)[JP] gamma-ray detectors. For statistical fluctuation of radioactivity under complex environment, some smoothing filtering methods are proposed to solve the problem. These methods include adopting method of arithmetic moving average, center of gravity, least squares of polynomial, slide converter of discrete funcion convolution etc. The process of spectrum data is realized, and the results are assessed in H/FWHM(Peak High/Full Width at Half Maximum) and peak area based on the Matlab programming. The results indicate that different methods smoothed spectrum have respective superiority in different ergoregion, but the Gaussian function theory in discrete function convolution slide method is used to filter the complex γ-spectrum on Embedded system platform, and the statistical fluctuation of γ-spectrum is filtered well.     

美国大学生创业的影响因素、特点与启示

我国大学生创业受到了社会的广泛关注,但由于起步较晚,仍处在探索之中,而美国开展大学生创业已有相当长的历史,积累了丰富的创业经验,学习和借鉴美国大学生创业的成熟模式和成功经验,对于我国大学生创业支持体系的构建,具有一定的现实意义。本文对美国大学生创业的影响因素和主要特点进行分析,以期对我国促进大学生创业和解决大学生创业中现存问题有所启示。     

基于主从分布式串行多机通信的电机控制系统的设计与实现

基于单片机的串行通信原理,设计了一种RS485通信接口的主从分布式串行多机通信系统.搭建了在PC机控制下的多个步进电机运转的硬件电路,设计了VC++的人机交互界面和主从机通信软件.系统具有性能稳定、运行可靠、扩展性强的特点,可用于远距离通信,适用于工业控制系统.     

泊松过程在用户上下线模型中的应用

提出了基于非齐次泊松过程的宽带拨号上网(ADSL)用户上下线模型.对用户上下线行为进行建模,并基于现网真实数据,使用模型计算用户24 h内的每时刻退出登录的平均概率,将模型的预测值与现网实测数据进行对比,分析了不同用户组退出登录概率一天内的变化和持续在线平均概率的变化.分析结果表明,提出的ADSL宽带用户上下线模型可以有效、量化地描述用户上下线行为,在ADSL宽带用户上下线行为的异常检测和舆情分析等领域具有较好的工程应用价值.     

少数民族流动人口研究综述——以2008年以来CNKI数据库分析为例

近年来关于少数民族流动人口研究颇多,侧重点集中在少数民族流动人口现状、特点的总体分析、城市适应问题、子女教育问题、民族差异引发的社会问题、社会保障与权益保护问题、对城市民族关系的影响等方面。总结、归纳、分析、概括以上多方面的研究成果,对研究存在的问题及空白点加以剖析,以求从全局的角度关注此研究。     

如何加强和改进离退休人员的思想政治工作

中国已经进入了老龄化社会,退休人员成为建设和谐社会的一支重要力量,离退休人员的思想状况如何已引起社会高度重视。本文结合工作实际情况,认真探讨分析离退休人员的思想现状,建议当前应从以下几方面切实加强和改进离退休人员的思想政治工作：一是加强退休党支部建设,为加强离退休人员思想政治工作提供组织保障;二是进一步改善退休工作部门的服务管理工作,为做好离退休人员思想政治工作提供职能保障;三是掌控离退休人员思想动态,加强和改进思想政治工作的方法;四是注重落实并提高退休人员的生活待遇,为加强离退休人员思想政治教育打下良好工作基础;五是积极开展健康有益的文体活动,为加强思想政治工作提供有效载体。     

MD simulation of nanometric cutting of copper with and without water lubrication

Three-dimensional molecular dynamics(MD)simulation was carried out to understand the mechanism of water lubrication in nanometric cutting.The water-lubricated cutting was compared with the dry cutting process in terms of lattice deformation,cutting force,heat and pressure distribution,and machined surface integrity.It was found that water molecules effectively reduce the friction between the tool and workpiece,the heat in the cutting zone and the pressure being generated on the tool surface,thus leading to prolonged tool life.Water molecules also enlarged the pressure-affected area,which decreased the roughness of the machined surface.     

上海地区冬季住宅室内外颗粒物浓度的相关性

对上海市某住宅建筑室内外PM10、PM2.5、PM1的浓度进行了测量,研究了最小通风量（外门窗关闭）条件下3种天气时颗粒浓度随时间变化的规律以及相关性,分析了颗粒物浓度与环境温湿度参数之间的关系.研究结果显示,测试期间,室内外空气中细颗粒（PM 2.5）占可吸入颗粒（PM 10）浓度比例分别达65％和87％以上;无明显室内源时,I/O比值小于1且随粒径减小而减小;室内外颗粒浓度相关性与粒径大小有关系,PM1、PM2.5的浓度相关性大于PM10.研究还表明,颗粒物浓度的关联性与天气状况有关系,多云、雨天和阴天时浓度关联性有显著差别;颗粒物的浓度受到室内外温湿度的影响,且受天气状况影响而呈现复杂性.     

秸秆灰为添加剂的粉煤灰免烧陶粒的试制

为克服粉煤灰免烧陶粒堆积密度高、应用性差的弊端,以秸秆灰为添加剂制备免烧陶粒.对粉煤灰活性激发机理、原料添加作用和陶粒物相组成(XRD)进行研究,得出制备陶粒的最佳过程参数为:5%的NaOH溶液预处理粉煤灰,成分配比(质量分数)为粉煤灰58.11%、氧化钙4.84%、水泥29.05%、秸秆灰8%.产品的主要性能指标为堆积密度785 kg/m3,比表面积11.1 m2/g,破碎率2.3%.对制得陶粒的浸出毒性和基本性能进行检测,结果表明,以秸秆灰为添加剂在一定条件下可制备出用于污水处理领域性能优良的功能陶粒,达到经济节能、变废为宝的目的.