具有砷(Ⅴ)还原能力的硫酸盐还原菌筛选及生长特性研究

采用亨盖特(Hungate)厌氧滚管技术从锦州湾受砷污染的底泥中分离纯化出3株具有砷(V)还原活性的硫酸盐还原菌,分别编号为S2、S3-11和S13.16S r RNA基因序列分析显示这3株菌分别与梭菌属(Clostridium)内的不同"种"之间亲缘关系最近.在As(V)初始浓度为1.0 mmol·L-1时,菌株S3-11可在10 h内还原23.4%的As(V),但当As(V)初始浓度增加到3.0或5.0 mmol·L-1时,菌株S2和S13则相对于S3-11展现出更强的砷还原能力,菌株S2甚至可以在7.0 mmol·L-1的砷环境中生长并在24 h内将14.2%的As(V)还原.菌株S2为严格厌氧菌,为直杆状革兰氏阳性菌,产芽孢,其细胞大小约为2.0μm×0.6μm,16S r RNA基因序列与梭菌属中Clostridium sporogenes strain JCM 7849同源性为99%.菌株S2可利用蔗糖、葡萄糖、甲酸钠、乳酸钠和乙酸钠为唯一碳源生长,生长适宜温度为30℃.     

过热度和高压压力对跨临界CO2汽车空调系统的影响

为对跨临界CO2空调系统进行优化设计,考虑压缩机绝热效率随压比的变化,分析了过热度、气体冷却器出口温度以及高压压力等对系统性能系数(COP)的影响,并与不考虑压缩机绝热效率随压比变化的情况进行了对比。结果表明:系统存在最佳高压和最佳过热度;最佳过热度随着气体冷却器出口温度的提高而增大;气体冷却器和压缩机效率是影响系统性能的主要因素;在较大高压压力下,与气体冷却器和压缩机效率相比,过热度的影响可以忽略不计。     

油气井筒出砂理论技术新进展

油气井筒出砂问题不仅仅出现在石油和天然气的生产过程中,海域天然气水合物(以下简称水合物)的开采和枯竭油气藏型储气库的运行同样伴随出砂导致的各种不利因素的影响。主要针对国内油气井筒出砂的研究现状进行三个层面介绍,分别为出砂的理论研究(宏观研究和微观研究)、出砂预测方法和出砂防治措施(机械挡砂、化学固沙、携砂管理和综合防砂)。通过研究分析业界专家的出砂理论和实验结果,结合具体的案例对油气井筒出砂研究存在的问题进行了归纳和总结。认为目前油气井筒出砂亟需解决的技术重点在枯竭油气藏型储气库注采井方面,同时要推动出砂技术与智能技术的结合,针对异常地层和复杂井况形成成熟的应对措施,提升单井产量和开采效率。通过本文的介绍可为井筒出砂的发展趋势和研究提供理论基础。     

混合动力汽车补偿模糊神经网络能量管理策略

以上海大众汽车公司某型号混合动力电动汽车(HEV)的设计要求为基础,提出了一种基于补偿模糊神经网络的能量控制策略,并采用动态调整步长的梯度下降法加快算法的收敛速度.分析了样本数据选取、输入、输出模糊分割和模糊规则提取对控制器性能的影响.利用ADVISOR2002仿真平台进行二次开发,完成了基于补偿模糊神经网络的控制策略、并联电力辅助控制策略和模糊控制策略的仿真比较.仿真结果表明,基于补偿模糊神经网络的控制器具有较强的自适应能力,可以较好提高混合动力汽车的燃油经济性和排放性.     

Cooperative interactions between odorant-binding proteins of Anopheles gambiae

To understand olfactory discrimination in Anopheles gambiae, we made six purified recombinant OBPs and investigated their ligand-binding properties. All OBPs were expressed in bacteria with additional production of OBP47 in the yeast Kluveromyces lactis. Ligand-binding experiments, performed with a diverse set of organic compounds, revealed marked differences between the OBPs. Using the fluorescent probe N-phenyl-1-naphthylamine, we also measured the binding curves for binary mixtures of OBPs and obtained, in some cases, unexpected behaviour, which could only be explained by the OBPs forming heterodimers with binding characteristics different from those of the component proteins. This shows that OBPs in mosquitoes can form complexes with novel ligand specificities, thus amplifying the repertoire of OBPs and the number of semiochemicals that can be discriminated. Confirmation of the likely role of heterodimers was demonstrated by in situ hybridisation, suggesting that OBP1 and OBP4 are co-expressed in some antennal sensilla of A. gambiae.     

Multivariate Time Series Model with Hierarchical Structure for Over‐Dispersed Discrete Outcomes

In this paper, we propose a multivariate time series model for over‐dispersed discrete data to explore the market structure based on sales count dynamics. We first discuss the microstructure to show that over‐dispersion is inherent in the modeling of market structure based on sales count data. The model is built on the likelihood function induced by decomposing sales count response variables according to products' competitiveness and conditioning on their sum of variables, and it augments them to higher levels by using the Poisson–multinomial relationship in a hierarchical way, represented as a tree structure for the market definition. State space priors are applied to the structured likelihood to develop dynamic generalized linear models for discrete outcomes. For the over‐dispersion problem, gamma compound Poisson variables for product sales counts and Dirichlet compound multinomial variables for their shares are connected in a hierarchical fashion. Instead of the density function of compound distributions, we propose a data augmentation approach for more efficient posterior computations in terms of the generated augmented variables, particularly for generating forecasts and predictive density. We present the empirical application using weekly product sales time series in a store to compare the proposed models accommodating over‐dispersion with alternative no over‐dispersed models by several model selection criteria, including in‐sample fit, out‐of‐sample forecasting errors and information criterion. The empirical results show that the proposed modeling works well for the over‐dispersed models based on compound Poisson variables and they provide improved results compared with models with no consideration of over‐dispersion. Copyright © 2014 John Wiley & Sons, Ltd.     

煤系高岭土及其深加工

介绍了我国煤系高岭土的储量、分布、性质、用途、发展现状和目前煤系高岭土的深加工产品,并指出目前我国开发利用高岭土中的问题及与先进国家的差距。     

球面共形天线阵列的稀布优化方法

为了抑制球面阵列峰值旁瓣电平,提出了一种基于改进遗传算法的阵元球面稀布优化算法(ESSA).首先采用遗传算法染色体对阵元位置信息进行特征提取,并利用染色体的的交叉、变异对位置信息进行优化重组,然后将重组前后的阵元位置信息合并成新的种群,最后在迭代过程中根据遗传算法适应度函数对阵元分布进行优化选择,从而建立最优阵元分布模型.与阵元球面均匀分布方法相比,EESA具有更大的阵元分布空间.仿真实验表明,经过遗传算法优化后所得最优阵元分布模型的峰值旁瓣电平较优化前约降低2.6dB,实验结果证明了ESSA可完全实现阵元可分布空间的随机寻优.     

互联网和社会网络中的信息交互传播模型

WS或BA等复杂网络模型可描述各类真实系统的拓扑规律和复杂性。而Petri网在处理系统内部通信和控制方面则具有特殊的优越性．本文结合广义随机Petri网和BA模型构造了一个可描述信息在互联网和社会系统中交互传播的复杂网络模型．     

宽带逆合成孔径雷达欺骗干扰技术研究

根据逆合成孔径雷达(ISAR)发射信号特点,该文基于模糊函数理论研究了宽带线性调频信号模糊函数及其分辨特性。用数字方法合成雷达假目标图像,实现对ISAR的欺骗性干扰。分析了数字图像合成器的工作原理和硬件实现,提出了调制器结构方案,该方案降低了资源消耗,提高了系统运行速度。理论分析和实例仿真表明,该方法可以逼真地产生假目标图像,达到了对逆合成孔径雷达欺骗干扰的预期效果。