BBM—likeB（2，2）方程的圈波及周期圈波解

应用微分方程动力系统理论研究BBM—likeB（2，2）方程的圈波及周期圈波解。在某些参数条件下给出该方程平面系统的相图，根据相图找到圈波及周期圈波解的存在条件，并求出了这两种解的参数形式表达式。通过软件Mathematica模拟了这两种解的平面波形图。     

辐射诱变愈伤组织选育耐寒型蕨菜

用γ射线对具有100%分化率的蕨菜愈伤组织进行辐射处理,将未致死的愈伤组织于1~2℃无光条件下处理20 d,再把未冻死的愈伤组织所分化的试管苗进行低温处理.将低温处理后的试管苗叶片、叶柄诱导的愈伤组织和分化的试管苗再进行低温选择,获得了耐寒蕨菜试管苗,由这种试管苗所形成的孢子苗仍然具有耐寒性.结果证明用剂量为5.16×10-1C.kg-1的γ射线对蕨菜的愈伤组织进行辐射处理,可选育出耐寒型蕨菜.     

含有氨基酸基团的聚(ε-己内酯)合成与表征

采用氨基酸钠游离的氨基引发ε-己内酯单体开环得到酯肽齐聚物,并以六亚甲基二异氰酸酯为扩链剂,将这些齐聚物扩链合成4种聚酯酰胺.将4种天然氨基酸(L-丙氨酸、L-亮氨酸、L-谷氨酸、L-赖氨酸)引入到聚(ε-己内酯)(poly(ε-caprolactone),PCL)中,合成和表征了4种含有氨基酸残基的聚合物.通过1H-NMR、FT-IR、水接触角、水吸收率和降解实验对该聚酯酰胺进行了表征.实验结果表明:经氨基酸改性PCL的亲水性和降解性得到了改善,其中含有L-赖氨酸残基的聚酯酰胺因亲水性最高,降解速率最快.     

Temporal and spatial distribution of tropospheric CO<Subscript>2</Subscript> over China based on satellite observations

Mid-troposphere CO₂ data retrieved by the AIRS (atmospheric infrared sounder) were validated with five ground-based stations and aircraft measurements in the Northern Hemisphere. AIRS CO₂ products show good agreement with ground and aircraft observations. The data had a monthly average accuracy better than 3 ppmv. In this study, the spatial and temporal distribution of mid-troposphere CO₂ from January 2003 to December 2008 was analyzed based on this satellite product. The average concentration of atmospheric CO₂ was higher in the Northern Hemisphere than in the Southern Hemisphere. The yearly average results show a gradual increase from 2003 to 2008. In China, the annual growth rate was about 2 ppmv/a, similar to the United States, Europe, Australia and India, but was slightly lower than Canada and Russia. Mid-troposphere CO₂ concentrations were higher over northern China than over southern areas, due to differences in natural conditions and industrial layout. There were four centers of high CO₂ concentration between 35° and 45°N over China, with low concentrations over Yunnan Province. There was a significant seasonal CO₂ variation with peak concentration in spring and the lowest concentration in autumn.     

Global vegetation change analysis based on MODIS data in recent twelve years①

Vegetation cover change is critical for understanding impacts and responses of vegetation to climate change. A study found that vegetation in the regions between 45°N-70°N was increasing using normalized difference vegetation index( NDVI) from 1981 to 1991 ten years ago. The global vegetation growth has changed because of climate change in recent twelve years( 2001- 2012). After thorough analysis based on satellite data,it is found that it is evident that the global vegetation changed( NDVI) little,and it is increasing slightly in Northern hemisphere while it is decreasing slightly in Southern Hemisphere. For different latitudes,vegetation is increasing 0.17% every year from 60°N to 70 °N( R~2= 0.47,P 0.013),while the vegetation is decreasing 0.11% every year from 10°N to 10° S( R~2= 0.54,P 0.004). For different continents,the vegetation in South America is decreasing 0.16% every year( R~2= 0.78,P 0.0001) and it is increasing 0.05% every year in Asia( R~2= 0.28,P 0.072) and 0.25% every year in Oceania( R~2= 0.24,P 0.1). The analysis of global vegetation in different seasons indicates that spatial distribution of global temperature and water vapor will affect the spatial distribution of vegetation,in turn,the spatial distribution of vegetation will also regulate the global temperature and water vapor spatial distribution at large scale. The growth and distribution of vegetation are mainly caused by the orbit of the celestial bodies,and a big data model based on gravitational-magmatic change with the solar or the galactic system as its center is proposed to be built for analyzing how the earth's orbit position in the solar and galaxy system affects spatial-temporal variations of global vegetation and temperature at large scale. These findings promise a holistic understanding of the global climate change and potential underlying mechanisms.     

Angular glint calculation and analysis of radar targets via adaptive cross approximation algorithm

Angular glint is a significant electromagnetic （EM） scattering signature of extended radar targets. Based on the adaptive cross approximation （ACA） algorithm accelerated method of moments （MoM） and the plane incident wave assumption, the narrowband, wideband and newly developed high-resolution range profile （HRRP） based angular glint calculation formulations are derived and applied to arbitrarily shaped three-dimensional （3D） perfectly electrical y conducting （PEC） objects. In addition, the near-field angular glint is emphasized, which is of great importance for radarseeker applications. Furthermore, with the HRRP based angular glint, an approach to rigorously determine range resolution cel s which own relatively smal er angular glint is provided. Numerical results are presented with new findings to demonstrate the usefulness of the developed formulations.     

纳米Ag（Ⅰ，Ⅲ）O粉体化学沉淀法制备条件的正交试验及其光学热分解性能研究

本文首先利用正交试验确定了液相沉淀法合成纳米AgO粉体的最佳制备条件。接着研究了最佳条件下制备的纳米AgO粉体的性能。UV—vis DRS分析结果表明，反射率随着AgO含量的增加而降低，高纯度AgO在400nm-1100nm波长范围内具有较强的吸收能力。TG—DTG分析结果表明，在N2气氛下，AgO热分解为Ag2O。的温度范围为100℃—200℃，Ag2O热分解为Ag的温度范围为400℃-450℃。     

说“音曰”

＂音曰＂这一训诂术语最早出现在东汉高诱的《吕氏春秋注》中,但历代注疏典籍用例甚少,古今辞书及训诂学著作均未提及。我们根据现有语料对＂音曰＂进行分析,认为它具有注音、释义、破通假、探同源、明连语等作用。通过对这一术语的分析,以期对训诂学研究和辞书编撰工作有所裨益。     

关于非线性离散随机系统的稳定性

通过极限方程理论,利用极限解的性质,给出了非线性时变离散时间随机系统上的一致全局渐近均方稳定的性质,它是在弱零状态检测和有界输出函数的假设条件基础上推出的.