Seven-frequency VLBI Observations of the GHz-Peaked-Spectrum Source OQ 208

We present quasi-simultaneous VLBI images of the GHz-Peaked-Spectrum radio source OQ 208 obtained with the Very Long Baseline Array at 1.4,1.7,2.3,5.0,8.4,15.4GHz and the European VLBI Network at 6.7 GHz.The low frequency(1.4,1.7 and 2.3GHz)ob- servations reveal a weak and extended steep-spectrum component at about 30mas away at position angle-110°,which may be a remnant emission.The radio structure of OQ 208 con- sists of two mini-lobes at 5.0,6.7,8.4 and 15.4 GHz.Our spectral analysis further confirms that the southwest lobe undergoes free-free absorption and finds that the free-free absorption is stronger in the inner region.By fitting the 8.4 GHz images from 1994 to 2005,we obtain a separation speed of 0.031±0.006 mas yr~(-1)between the two mini-lobes.This indicates a jet proper motion of 0.105±0.020 c and a kinematic age of 219±42 yr for the radio source.     

Shapes and Pole Orientations of Asteroids (360) Carlova and (209) Dido

Several light-curves of asteroid (360) Carlova and (209) Dido in different epochs were analyzed to determine shapes and pole orientations by means of AM-method and least squares method. New values of a/b, b/c, λ _p and β _p for asteroid (360) Carlova were obtained, which are 1.52°, 1.5°, 120 ± 6° and 66 ± 7°, respectively. We report a first determination of the parameters of (209) Dido which are 1.3°, 1.1°, 221 ± 6° and 37 ± 3°, respectively.     

New Methods of Fitting the Membership Function of Oceanic Water Masses

1　Introduction　Watermassanalysisisanimportantsubjectinphys icaloceanographystudies (PickardandEmery ,1 990 ;YeandLi,1 992 ) .Helland Hansenplottedin 1 91 6theT Scurve ,whichisafterwardsknownasoneoftheT Sdiagrams ,andsuggestedthatawatermasscanbedefinedby…     

NGC4151的光变周期分析(英)

本文利用地面光学望远镜对NGC4151进行国际联测所得的结果，通过周期日方法和逐步回归方法得到了该目标的一些较为明显的光变周期．结果表明，NGC4151存在两个主要光变周期．一个是所有光学波段存在约14天的周期，另一个是连续谱存在约30天周期，而对于Hα和Hβ则分别为24和38天的周期．     

The effect of strength anisotropy on the bearing capacity of spudcan foundations

The vertical bearing capacity of spudcan foundations in strength anisotropic soils is investigated numerically using the MIT-S1 model implemented in the AFENA finite element package. The model in AFENA is validated against existing laboratory test data of normally consolidated soil. The bearing capacities of spudcans in soils with isotropic and anisotropic strengths are compared. Soil with isotropic strength is simulated using an elasto-plastic model. It is found that the bearing capacity of a spudcan in an anisotropic soil is reduced by about 9% for a rough spudcan and 3% for a smooth spudcan on average. There is a combined effect of soil anisotropy and spudcan roughness on the spudcan bearing capacity. Moreover, the effect of the pressuremeter strength of an anisotropic soil on foundation capacity can’t be ignored.     

Vertical amplitude reduction of Rayleigh waves by a row of piles in a poroelastic half‐space

A row of rigid piles is addressed as the countermeasures for isolating Rayleigh waves in a poroelastic half‐space. The complex characteristic equations for Rayleigh waves are derived via Biot's theory and their existence conditions are given. The piles are modeled as Euler–Bernoulli beams with longitudinal displacements and the diffracted field by each pile is constructed only with Rayleigh waves. Six infinite linear systems of algebraic equations are obtained in terms of the equilibrium of forces and continuity of displacements at the pile–soil interfaces. The systems are subsequently solved in the complex least‐squares sense. The influence of certain pile and soil characteristics such as the permeability of poroelastic soil, spacing between the piles and length of the piles on the isolating performance of a pile barrier is investigated. Computed results show that the permeability of poroelastic soil displays a significant effect on the vertical amplitude reduction of Rayleigh waves. Copyright © 2009 John Wiley & Sons, Ltd.     

Experimental study of extreme shear stress for shallow flow under simulated rainfall

The raindrop impact and overland flow are two major factors causing soil detachment and particle transportation. In this study, the turbulent characteristics of the shallow rain‐impacted water flow were investigated using a 2‐D fibre‐optic laser Doppler velocimetry (FLDV) and an artificial rainfall simulator. The fluctuating turbulent shear stress was computed using digital data processing techniques. The experimental data showed that the Reynolds shear stress follows a probability distribution with heavy tails. The tail probability increases with an increase of rainfall intensity or raindrop diameter, and it decreases with an increase of Reynolds number. A modified empirical equation was derived using both the raindrop diameter and rainfall intensity as independent variables to provide a better prediction of the Darcy‐Weisbach friction coefficient f under rainfall conditions. Copyright © 2009 John Wiley & Sons, Ltd.     

微带发夹型滤波器的设计

微带发夹型滤波器具有结构紧凑,尺寸小、重量轻和成本低等优点.根据微波电路设计的基本理论,利用微波电路ADS软件,设计了一个微带发夹型滤波器,其中心频率为2.3GHz时,通带带宽为200MHz,通带内插损小于1.7dB.仿真结果表明所设计的滤波器不仅尺寸小,而且性能优越,具有很高的实用价值.     

Survey of cyanomyovirus abundance in Shantou coastal waters by g20

To understand the genetic diversity and population changes in cyanophages in the coastal waters of Shantou,northeast South China Sea,we used the capsid assembly protein gene g 20 as a marker of the abundance and phylogeny of natural cyanomyovirus communities. The abundance of total viruses,heterotrophic bacteria,and picophytoplankton in the coastal waters was monitored with flow cytometry. Hydrological parameters(NO ˉ 3,NO ˉ 2,NH 3,soluble reactive phosphorus,total dissolved nitrogen,total dissolved phosphorus,dissolved oxygen,chemical oxygen demand,temperature,salinity,and chlorophyll a concentration) and microbial abundance(total viruses,total bacteria,P rochlorococcus,Synechococcus,and eukaryotes) were measured in the upper and lower layers at four sampling sites in the research area. In the direct viral counts,cyanomyoviruses accounted for 1.92% to 10% of the total viral community. A phylogenetic analysis showed that the g 20 sequences in the Shantou coastal waters were very diverse,distributed in eight distinct operational taxonomic units,including the newly formed Cluster W. The g 20 gene copies inferred from real time PCR assay indicated that cyanomyoviruses were correlated significantly with the heterotrophic bacteria numbers and the nitrate and chlorophyll a concentrations. These results suggest that cyanomyoviruses are ubiquitous and are an abundant component of the virioplankton in Shantou coastal waters.