科创中国

针对存在相干信源时,传统的DOA估计算法失效问题,提出一种基于实值特征子空间的虚拟阵列解相干算法.该算法根据虚拟阵列变换的思想,利用阵列接收数据构造虚拟子阵,实现对信号的解相干处理,并将协方差矩阵从复数域变换为实数域,获得一个实值信号子空间,最后利用实数域ESPRIT (Unitary ESPRIT)估计信号波达方向.该方法避免了阵列孔径损失,保持了阵列的空间分辨率,估计精度高,利用个阵元可估计个信源,且引入实数域处理和无需空间谱搜索,运算量小.计算机仿真验证了该方法的有效性和优越性.

为了检测受噪声污染图像的边缘,提出了一种基于变差函数和方向小波的多尺度边缘检测新方法.首先,在我们前期研究成果的基础上,基于变差函数理论,提出了图像中45度和135度方向边缘的判别准则.然后根据图像中边缘的方向性,选择合适的方向小波旋转参数,再利用方向小波对各个子区域进行不同尺度小波变换.仿真实验表明,对于受高斯白噪声污染的图像,所提出的边缘检测方法无论在边缘定位的准确性还是在去除伪边缘点方面,均优于传统的小波边缘检测方法.

以大庆萨尔图万达广场为例,从万达城市综合体的创作思路、选址模式、功能组织、建筑形态等几方面阐述了万达城市综合体在寒冷地区城市中的创作体会.

目的:观察肌肉注射咪达唑仑治疗儿童急性惊厥的疗效及安全性.方法:选取我院儿科就诊的急性惊厥患儿100例,随机分为治疗组与对照组各50例,治疗组肌肉注射咪达唑仑0.2~0.3 mg/kg,对照组静脉注射地西泮0.3~0.5 mg/kg.结果:治疗组有效率92.0%,对照组有效率96.0%,两组比较差异无统计学意义(P>0.05);治疗组患儿惊厥平均控制时间为(3.37±1.51)min,对照组惊厥平均控制时间为(2.96±1.85)min,两组惊厥控制有效患儿平均控制时间比较差异无统计学意义(P>0.05).结论:肌肉注射咪达唑仑治疗儿童急性惊厥起效快、疗效可靠,安全性高.

Lesser kestrels Falco naumanni are migratory central-place foragers that breed in dynamic arable landscapes. After arriving from migration, kestrels have no knowledge of the distribution of crops, and consequently prey, around their colony. The energy demand of pairs increases as breeding season progresses, but at the same time prey abundance, and their knowledge on prey distribution, also increases. Wind can have a strong influence on flight cost and kestrels should try to reduce energy expendi- ture when possible. When prey abundance is low, kestrels have little knowledge of prey distribution, and pairs have no chicks, they could reduce foraging flight cost by leaving the colony with tailwinds. When prey is abundant, knowledge on prey distribu- tion has increased, and chick demand is high, kestrels should fly to the most favorable foraging patches. We analyzed foraging trips directions in a lesser kestrel colony along the breeding season and in relation to wind speed and direction. We recorded 664 foraging trips from 19 individuals using GPS-dataloggers. We found that outward flights direction changed from uniform to a concentrated distribution along the season, as prey abundance and individual experience increased. We also found a temporal trend in the angular difference between outward flights and wind directions, with low values early in the season and then increa- sing as expected, but again low values at the end, contrary to expectation. Results suggest changes in kestrels foraging strategy along the season in relation to wind. Kestrels depart more with tailwinds in exploratory flights early in the season, while there is a spurious coincidence in direction to preferred foraging patches and dominant wind direction at the end [Current Zoology 60 (5): 604-615, 2014].

进入21世纪,大学英语教师职业的发展面临着严峻的挑战和诸多的发展机遇.各行各业对国际型、复合型人才的迫切需求对高等学校的人才培养目标提出了更新和更高的要求.ESP(专门用途英语)教学将逐渐成为大学英语教学的主流,大学英语教师未来职业发展的方向必然要转型为ESP教学.

Revised September 2013 by K.A. Olive (University of Minnesota) and J.A. Peacock (University of Edinburgh).

伽达默尔的教化解释学就是一种实践哲学,而且是一种新亚里士多德主义的解释学实践哲学,它强调通过后天的日常交往、练习和习惯来分享共同的信念、价值与习俗,实践共同的善;强调过一种政治的生活或共同体的生活需要共同体中每位成员的互相友爱或友善.

研究一类具有时滞和非线性发生率的生态流行病模型.以滞量为参数,通过分析特征方程,得到了正平衡点局部稳定和Hopf分支存在的条件.同时,应用中心流形定理和规范型理论,得到了分支方向和分支周期解的稳定性计算公式.最后对所得理论结果进行了数值模拟.

以转型陷阱和自组织理论为视角,对我国竞技体育体制改革出现的问题进行研究,研究认为:在渐进式改革的进程中,使转型过程停滞并定型化的机会很多;中国竞技体育在29届奥运会后最现实的问题是改革的停滞,要打破转型陷阱,需要正确理解改革、发展、稳定三者之间的内在联系,界定好政府改革中的角色定位,正视转型陷阱格局,把加快扭转转型陷阱紧迫感同科学求实的精神结合起来,形成解决社会矛盾和冲突的制度化方式,激活涨落因子,推进我国竞技体育体制进一步完善和发展.