FeO的制备及其室温下稳定性研究

采用草酸亚铁在高纯Ar气条件下加热分解制备FeO,借助于XRD图谱探讨保护气氛对FeO制备的影响以及FeO在常温下存放的稳定性。结果表明,Ar气保护流量低于400mL/min时,产物相除FeO相外,还分别含有Fe3O4、Fe相,甚至有Fe2O3相杂质;较佳的Ar气保护流量为400mL/min,此时制备的FeO纯度高,其他杂质较少。新制备的FeO样品在干燥、潮湿和室内自然环境中保存,90d内未发生明显相的变化。     

基于蚁群优化算法的云计算资源负载均衡研究

针对云数据中心虚拟机分配物理机时存在负载不均衡的问题,提出了一种基于蚁群优化算法的资源调度算法.对问题场景进行了分析,提出了数据中心负载不均衡度以及物理机与虚拟机之间不匹配度的概念,并给出了问题的形式化描述.在蚁群算法选择概率规则中参考了用户对虚拟机资源的需求,尽量避免对相同类型虚拟机部署在一台物理机上,同时对信息素的初始化、信息素的更新进行了改进.通过CloudSim模拟平台进行仿真实验,并与其他的分配算法进行了比较,实验结果表明:该调度算法能够快速地完成虚拟机的放置,并且使云数据中心的物理机具有较低负载不均衡度,提高了资源的利用率.     

基于后缀数组改进的全文索引结构研究

为在网络数据中搜索到所需相关数据, 通过对基于后缀数组的全文索引结构的改进研究, 设计和实现一种降低空间占用率并有效提高索引速度的全文索引结构加权有向词图。通过实验证明, 加权有向词图在相同问题规模下能降低存储空间, 同时不影响检索的效率, 是一种更为高效的全文索引结构。     

含自适应阈值的ARMA网络流量异常检测算法

传统的网络管理方法已不能适应网络复杂性的要求,不能准确刻画网络异常行为,从而影响检测精度.针对这个问题,提出含自适应阈值的ARMA网络流量异常检测算法,利用滑动平均模型预测网络流量,利用中心极限定理确定动态的阈值区间,通过判断网络流量误差是否落在阈值区间作为检测点是否异常的准则.仿真结果表明,该模型能准确地描述网络的运行状况,具有很高的可用性.     

磷石膏脱色增白工艺条件的研究

文章采用煅烧与酸浸相结合的方法开展磷石膏脱色增白工艺条件的研究。以磷石膏白度为主要考察指标,通过单因素条件实验和正交实验,分别考察了煅烧温度、煅烧时间、酸浸时间、酸浸温度、硫酸质量分数和液固比等因素的变化对磷石膏白度的影响,所确定的较佳脱色增白工艺条件为:煅烧温度600℃、煅烧时间70min、酸浸时间3.5h、酸浸温度90℃、硫酸质量分数35%、液固比4∶1。此条件下的重复实验结果表明,磷石膏的白度可由33.0%提高到89.8%。     

基于需求分析视角的科技人才创新创业激励机制研究

在对覆盖浙江全省11个市(地)共2 323名科技人才激发其创新创业机制现状调查的基础上,从当前存在的主要困难、制约因素及对政府改进工作期许等方面,分析了科技人才创新创业需求。基于难于争取到项目和经费不足的主要困难,科研激励机制不完善、项目等科技资源分配不合理的主要制约因素,以及最希望政府优先建立完善公平合理的科技立项程序与审批制度、科技成果的评价和奖励制度的重点需求,针对性提出了关于激励科技人才创新创业机制的政策建议。     

Construction of Streptomyces lydicus A01 transformant with the chit33 gene from Trichoderma harzianum CECT2413 and its biocontrol effect on Fusaria

Streptomyces lydicus A01 resists many plant pathogens (including Fusarium spp.) by producing the antifungal agent natamycin, which binds to the ergosterol of fungal cell membranes and inhibits the growth of pathogens. Trichoderma harzianum CECT2413 is a widely-distributed soil fungus that antagonizes several plant fungal pathogens (including Fusarium spp.) by producing chi-tinase and degrading chitin, a major component of the fungal cell wall. This study attempted to enhance the biocontrol effect of S. lydicus A01 on Fusarium spp. by transforming the chitinase gene of Trichoderma. Chitinase and natamycin could act synergisti-cally on both the cell walls and cell membranes of pathogens. The 33-kD chitinase-encoding gene (chit33) was cloned and conju-gal-transformed from T. harzianum CECT2413 to S. lydicus A01, and then confirmed via polymerase chain reaction (PCR) assays. Subsequent analyses using the 3,5-dinitrosalicylic acid (DNS) method and ultraviolet spectrophotometry showed that compared with its wild type strain (WT), the S. lydicus A01 conjugal transformant (CT) with chit33 gene exhibited substantially higher chi-tinase activity and natamycin production. The resistance of S. lydicus A01-chit33 CT and WT to four Fusaria in crops and vegetables was tested via the cup-plate method. Compared with the WT, the conjugal transformant of S. lydicus A01 with chit33 gene from T. harzianum CECT2413 showed greatly increased biocontrol effect on fusarium disease. This study would be beneficial to the development of high-quality antifungal bio-agents for agricultural applications via the synergy between the previously non-existent and pre-existing functions achieved through heterogeneous gene transformation.     

Generalized multiparticle Mie modeling of light scattering by cells

The development of nanobiology requires a fundamental understanding of the interaction features between light and cells as well as cells containing nanoparticles. In this study, the generalized multiparticle Mie (GMM) theory was employed to calculate the scattering properties of cells under refractive index matching conditions. The angular distribution of scattered light is statistically averaged to obtain a good fit for the experimental results. Based on a simplified cell model, the variabilities between the scattered light pattern of normal cells and that of cancerous cells were examined. The results indicate that the small angle scattering is sensitive to the organelle distribution, which could be applied in the diagnostics of cancerous cells. Finally, the effects of cellular uptake of nanoparticles on the scattering pattern was also investigated.     

宁夏地区水泥强度富余系数R_c研究

结合宁夏地区实际特点,选取不同来源不同等级水泥测试其实际强度,在保证可靠性基础上计算水泥强度富余系数范围.所得结果可为宁夏地区混凝土生产过程中减少水泥用量、降低成本和提高性能提供理论依据.     

碱土金属氧化物掺杂CeO2催化1,4-丁二醇选择性脱水合成3-丁烯-1-醇

采用浸渍法制备了碱土金属氧化物MO(MgO、CaO、SrO和BaO)掺杂的MO-CeO2催化剂,通过X-射线粉末衍射、H2程序升温还原和CO2程序升温脱附等手段表征了催化剂的结构和表面性质,并考察其对1,4-丁二醇选择性脱水合成3-丁烯-1-醇反应的催化性能.结果表明,碱土金属氧化物掺杂未改变CeO2的萤石型结构,但可增加MO-CeO2催化剂的氧缺陷位和表面碱性位点,进而提高其催化1,4-丁二醇选择性脱水的活性和3-丁烯-1-醇的选择性.其中,CaO-CeO2催化剂表现出最优的催化性能,3-丁烯-1-醇收率达52.44%.