Isolation and characterization of H7N9 viruses from live poultry markets--Implication of the source of current H7N9 infection in humans

On March 31, 2013, the National Health and Family Planning Commission announced that human infections with a previously undescribed influenza A (H7N9) virus had occurred in Shanghai and Anhui Province, China. To investigate the possible origins of the H7N9 viruses causing these human infections, we collected 970 samples, including drinking water, soil, and cloacal and tracheal swabs of poultry from live poultry markets and poultry farms in Shanghai and Anhui Province. Twenty samples were positive for the H7N9 influenza virus. Notably, all 20 viruses were isolated from samples collected from live poultry markets in Shanghai. Phylogenetic analyses showed that the six internal genes of these novel human H7N9 viruses were derived from avian H9N2 viruses, but the ancestor of their HA and NA genes is uncertain. When we examined the phylogenetic relationship between the H7N9 isolates from live poultry markets and the viruses that caused the human infections, we found that they shared high homology across all eight gene segments. We thus identified the direct avian origin of the H7N9 influenza viruses that caused the human infections. Importantly, we observed that the H7N9 viruses isolated from humans had acquired critical mutations that made them more "human-like". It is therefore imperative to take strong measures to control the spread of H7N9 viruses in birds and humans to prevent further threats to human health.     

互联网技术领域科研合作网络分析

首先,对中国知网收录的互联网技术领域中的所有论文作者进行统计,建立了科研合作网络,运用统计学方法对其网络基本特征进行了初步的分析.然后,应用复杂理论方法进行实证分析,发现该复杂网络具有无标度特征.最后,计算了5个较大的内部连通子网络的聚集系数、直径等网络参数,发现它们呈现小世界特征.研究结果对于获取科技信息、凝聚创新思想、共享研究资源有一定的参考价值.     

拓展训练引入高等职业院校体育教学中的价值研究

本文通过分析高等职业院校体育教学目标的设置与教学内容的选择,指出了高等职业院校开设拓展训练教学的价值。开设拓展训练教学对构建高等职业院校特色体育课程、深化教学改革、完善体育课程评价体系、提升高职院校学生的整体素质具有重要意义。     

关于丢番图方程x^3-1=13py^2的整数解

设素数p≡1（mod12）,（p/13）=-1.关于丢番图方程x^3-1=13py^2的初等解法至今仍未解决.主要利用递归序列、同余式、平方剩余、Pell方程的解的性质,证明了丢番图方程x^3-1=13py^2仅有整数解（x,y）=（1,0）.     

互联系统结构保留的频率慢动态仿真分析

大规模互联电力系统(LIPS)在长期动态中由于频率和电压的慢动态可能引发生存性危机,最终造成一些大停电事故.为此,作为LIPS慢动态频率控制器设计的第一步,文中对LIPS结构保留的频率慢动态进行了建模和仿真.在以区域惯量中心频率为区域均一频率的假设下,建立了LIPS结构保留的频率慢动态模型,并提出了时域仿真计算方法.将该方法应用于双区域4机系统和IEEE 30节点3区域系统,并在4机系统上与暂态稳定程序作比较,结果均表明相应模型和方法是可行和有效的.     

顶空固相微萃取-气相色谱-质谱法分析新鲜山黄皮叶及果皮挥发性成分

 采用顶空固相微萃取-气相色谱-质谱法分析了新鲜山黄皮叶及果皮挥发性成分。山黄皮果皮挥发性主要成分及其含量为：肉豆蔻醚[BF]（61.02%）、β-月桂烯（23.46%）、异松油烯（6.29%）、β 细辛脑（1.49%）、（E,E,E）-3,7,11,15-四甲基-1,3,6,10,14-十六五烯（1.43%）、β-红没药烯（1.27%）、3-蒈烯（0.75%）、顺-桃金娘烷醇（0.59%）。山黄皮叶挥发性主要成分及其含量为：肉豆蔻（47.52%）、异松油烯（23.83%）、3 蒈烯（5.95%）、β 红没药烯（4.74%）、（+）-4-蒈烯（3.12%）、β-月桂烯（2.72%）、对薄荷-8-烯（1.47%）、D-柠檬烯（1.45%）、水芹烯（1.22%）和β-细辛脑（1.04%）。     

基于最小速率保证的IEEE 80216e公平调度算法

针对IEEE 80216e协议的特点,提出了一种基于最小速率保证的IEEE 80216e 公平 调度（MTRFS）算法。算法支持多种业务流类型并可保障业务流的最小预约速率。该算法中 引入了补偿模式,以保障处在恶劣信道条件下的业务流的最小速率。同时,该算法对高级别 业务流和信道条件好的业务流提供尽可能多的带宽,以保障其QoS性能和系统吞吐量的最大 化。仿真表明,该算法能够保证业务流的最小预约速率,区别对待不同优先级的业务流;无 论是其公平性能还是吞吐量性能都优于传统的PF算法。该算法与IE     

水电站计算机监控系统单神经元自适应PID功率调节的研究

水力发电机组是一个复杂的非线性控制对象,为保证水电站发电机组功率调节具有快速、稳定的控制特性及良好的鲁棒性,本文提出在水电站计算机监控系统有功功率调节中采用单神经元自适应PID功率调节方式.PID控制的关键问题是PID参数的整定,单神经元自适应PID控制器由于其权值可以在线调整,具有较强的自学习和自适应能力,仿真结果表明改进的单神经元PID控制器比传统的控制器拥有更好的稳定性、动态性能和鲁棒性.     

Rational doping for zinc oxide and its influences on morphology and optical properties

Zinc oxide(ZnO) nanopowders doped with different metal ions(Me, Me = Sn4+, In3+, Mn2+, and Co2+) are prepared by a simple sol–gel method. Influences of the ion doping on morphology and optical properties of the resulting ZnxMeyO are investigated by scanning electron microscopy, X-ray diffraction, UV-vis absorption spectrum, and photoluminescence. The morphology of ZnO can be tailored by ion doping, which is closely related not only to the ionic radii and electronegativities of the doped ions, but also to their oxidation states and electron configurations. The optical band gap and photoluminescence of ZnO can also be modulated by ion doping, which results from a combination of different effects, Burstein–Moss, band tail, charge compensation, sp–d exchange, non-radiative recombination, and blocking barrier. This may offer us a viable approach to tuning the(optical) properties of ZnO-based materials via rational ion doping.