长江口附近海域台风浪特征分析

为了解长江口附近海域台风浪特征,于1999年台风季节利用SBE－26型浪潮仪在长江口外皮礁测点对9904、9906和9912号三次台风过程进行波浪观测,并对H1／3＞1．2m波高春对应周期进行统计分析,对测到的全部90组波面记录进行功率分析,得到了一系列有用的结论。     

无感电阻电网络分流器性能实验

对新研制的无感电阻网络分流器进行了测量重复性,线性度试验和阶跃波响应试验,试验证明所研制的无感电阻网络分流器可用于kV级脉冲大电流的测量和雷电浪涌（冲击）模拟器短路电的波形校准。     

The compositions, sources, and size distribution of the dust storm from China in spring of 2000 and its impact on the global environment

The average mass concentration of the aerosols in Beijing during the dust storm in the spring of 2000 was ~6000 mg·m^-3, ~30 times as high as that in the non-dust storm days. The enrichment factors of the pollution elements As, Sb and Se were higher than those in the non-dust storm days. This indicated that As, Sb and Se resulted from the pollution sources of those areas, through which the dust storm passed during their long-range transport, in addition to the local pollution sources in Beijing. The enrichment factors of the Pb, Zn, Cd and Cu were much less than those in the non-dust storm days, suggesting that the local pollution sources in Beijing area contributed to them mostly. The enrichment factors of elements Al, Fe, Sc, Mn, Na, Ni, Cr, V and Co were close to 1, showing that these elements originated from crust. The concentration of S in the dust storm was ~10 mg·m^-3, 4 times as high as that in non-dust storm. S in the aerosols resulted from the adsorption of gaseous SO₂ and the consequent transformation on it. The aerosols of the dust storm contained 16.1% and 76.9% of fine particles with the sizes less than 2.1 and 9.0 mm, respectively, while it had a large number of coarse particles. It was noted that a considerable portion of Fe(Ⅱ) was detected from the dust storm. Fe(Ⅱ) could easily dissolve in seawater to be nutrient for phytoplankton and would lead to the increase of the emission of dimethylsulfide (DMS) from the ocean. The feedbacks of Fe coupled with S in atmosphere might be the important mechanism that would affect the primary productivity in Pacific and/or the global climate change.     

TRMM卫星LIS闪电资料在数值模式中的应用

利用热带降雨测量卫星（TRMM）上闪电成像仪（LIS）和测雨雷达（PR）资料,得到了LIS闪电发生率与PR对流降水之间的统计关系。将由LIS闪电数据反演的对流降水等资料,连续同化加入到改进的区域预报模式（ARPS）的初始场中,对江淮流域暴雨进行模拟,结果显示暴雨的中心位置和强度预报都得到了明显的改善。     

GCM模式中斜压波包的动力学特征

利用时间滞后相关和波包的复分解方法,分析了GCM模式资料300hpa的经向风扰动。计算了波包的波长、波数、相速和群速等物理量,揭示了波包的基本动力学特征。斜压波包的波长为数千公里,相速为10m/s左右。波包包络的传播速度为相速的2～3倍,下游发展仍是斜压波包的主要特征。同时,斜压波包在传播过程中显示出较好的相干性,即波包的包络能较长时间内维持其形状不变。详细分析了波包性质的季节变化和南北半球的差异,并将模式资料的结果与实测资料做了比较。     

Storm-time ionospheric disturbances monitored by GPS beacon measurements

The Total Electron Content (TEC) during three great storms, from April to August 2000, was collected by means of a GPS receiver located in Jingzhou (30.4° N, 112.2° E). The time-latitude-dependent features of ionospheric storms are identified using TEC difference images based on the deviations of TEC during storm relative to quiet time. The responses of ionospheric TEC to magnetic storms were analyzed. The results show that: 1) In middle and low latitude, ionospheric storms effects are more apparent in local day time than at night: 2) Ionospheric storm effects are more dominant near the hump of the equatorial anomaly region than in other regions of TEC measurements; 3) The positive effects during the main phase of ionospheric storm may be caused by electric fields in low latitude; 4) During the recovery period of ionospheric storm, the negative phase of storm may be due to the perturbation of the neutral gas composition. Foundation item: Supported by the National Natural Science Foundation of China (49984001) Biography: Pei Xiao-hong (1977-), male, Master candidate, research direction: studying ionosphere on GPS beacons.     

辐射沙洲西洋水道激流特征及成因分析

利用1980年和2001年的激流资料和2008年新测的激流水沙资料,对辐射沙洲西洋水道激流特征及成因进行了分析.结果表明:(1)激流具有流速特别大、流向变化小及各层水体含沙量与流速响应良好的特征;(2)一方面,西洋水道喇叭口状的特殊地形易产生涌潮现象,但激流时刻未出现异常潮位变化;另一方面,激流各层流速和含沙量均同时突增,其中底层流速最大为3.71 m/s,最大含沙量为14.94 kg/m3,而风应力不可能使近10 m深的底层海流产生如此大的流速并获得掀起大量底层泥沙的巨大能量,且相邻测站未同时测得激流,故假潮和风应力均不是激流的必要成因,今后应从潮流的辐合和特殊的地形条件两方面进一步探讨激流现象的形成机制.     

离心式压气机喘振主动控制硬件在环仿真

为了减少压气机喘振控制系统的开发时间和费用,基于dSPACE实时仿真平台,应用Matlab/Simulink系统建模方法,搭建了压气机喘振主动控制系统的硬件在环仿真平台,建立了离心式压气机喘振仿真模型,利用LabVIEW软件实现了压气机喘振模糊控制算法,详细阐述和分析了关键信号的处理方法和仿真结果。结果表明,该算法能够满足实时性要求,具有良好的控制效果。     

Statistic characteristics of severe convective storm during Warm-Season in the Beijing-Tianjin region and its vicinity

This study analyzed the climatological characteristics of severe convective storms in the Beijing and Tianjin region and its vicinity based on the Doppler radar data of Tanggu during May-August of 2003-2007. The climatological characteristics, e.g. storm area, volume, top height, max reflectivity, life time and motion, are analyzed. The results include： 75% of all storms in the Beijing-Tianjin region last no more than 30 minutes, and most storms have a volume less than 400 kin3; most storms move from southwest to northeast while the speed is between 10-30 km/h; the mean storm top height is about 6 km, but some strong convective storms can have a top height larger than 15 kin; finally, storm area and volume have a similar geographical distribution character showing increasing trends from west to east. Compared with the statistic results based on the conventional surface meteorological observations, the results based on the radar data can present not only 3D spatial statistic results of convective storms （e.g., volume and top height）, but also the quantitative climatological characteristics, such as the lifetime and speed distributions. These statistical results are useful for studying the climatic characteristics of convective storms in the Beijing-Tianjin region and its vicinity.     

The planimetric unfold method of fullerene cage structure

Two kinds of planimetric diagrams, which consist of the boat form F₆ and F₅, the storm petrel form F₆ and F₅, respectively, were proposed to express the geometric structure of fullerene cage in this study. There are two chief advantages using the diagrams: (ⅰ) the spatial symmetrical characteristic of fullerene cage is not destroyed; (ⅱ) the coordination forms of F₅ and F₆in the structure can be clearly expressed. This work has laid the foundation for studying the structural geometry of fullerene cage and its quantum chemistry and property.