Sub-arcsec 10 μm imaging of β pictoris and other star disk candidates

We have used the ESO 10 q224v14h2828p456/xxlarge956.gif" alt="mgr" align="MIDDLE" BORDER="0">m camera, TIMMI, to image with a very high angular resolution (PFoV: 0.3q224v14h2828p456/xxlarge8243.gif" alt="Prime" align="MIDDLE" BORDER="0">; FWHM:0.9q224v14h2828p456/xxlarge8243.gif" alt="Prime" align="MIDDLE" BORDER="0">) several main-sequence star disk candidates. Information on the q224v14h2828p456/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-Pictoris dust disk has been obtained in a region largely inaccessible to previous observations: 0–80 AU, with a resolution of about 5 AU after deconvolution. Another promising target for 10 q224v14h2828p456/xxlarge956.gif" alt="mgr" align="MIDDLE" BORDER="0">m imaging, 51 Ophiuchi, appears point-like.based on data collected at the European Southern Observatory (ESO), La Silla, Chile     

Channel overflows of the Pōhue Bay flow,Mauna Loa,Hawai'i: examples of the contrast between surface and interior lava

A number of overflows from a large lava channel and tube system on the southwest rift zone of Mauna Loa were studied. Initial overflows were very low viscosity gas-rich pq6h925880rx28128/xxlarge257.gif" alt="amacr" align="BASELINE" BORDER="0">hoehoe evidenced by flow-unit aspect ratios and vesicle sizes and contents. Calculated volumetric flow-rates in the channel range between 80 and 890 m³/s, and those of the overflows between 35 and 110 m³/s. After traveling tens to hundreds of meters the tops of these sheet-like overflows were disrupted into a surface composed of clinker and pq6h925880rx28128/xxlarge257.gif" alt="amacr" align="BASELINE" BORDER="0">hoehoe fragments. After these 'a'q6h925880rx28128/xxlarge257.gif" alt="amacr" align="BASELINE" BORDER="0"> overflows came to rest, lava from the interiors was able to break out on to the surface as pq6h925880rx28128/xxlarge257.gif" alt="amacr" align="BASELINE" BORDER="0">hoehoe. The surface structure of a lava flow records the interaction between the differential shear rate (usually correlated with the volumetric flow-rate) and viscosity-induced resistance to flow. However, the interior of a flow, being better insulated, may react differently or record a later set of emplacement conditions. Clefts of toothpaste lava occurring within fields of clinker on proximal-type 'a'q6h925880rx28128/xxlarge257.gif" alt="amacr" align="BASELINE" BORDER="0"> flows also record different shear rates during different times of flow emplacement. The interplay between viscosity and shear rate determines the final morphological lava type, and although no specific portion of lava ever makes a transition from 'a'q6h925880rx28128/xxlarge257.gif" alt="amacr" align="BASELINE" BORDER="0"> back to pq6h925880rx28128/xxlarge257.gif" alt="amacr" align="BASELINE" BORDER="0">hoehoe, parts of a flow can appear to do so.     

流速仪信号采集系统设计

介绍了流速仪检定系统的工作原理,分析流速仪信号特点和采集难点,针对流速仪信号受外界干扰信号波形复杂问题,设计信号采集硬件调理电路。针对流速仪信号周期多样性问题,对测频法和测周法进行误差分析和比较,确定在不同速度区间使用不同软件滤波的方法。通过硬件调理电路及软件滤波仿真验证,证明设计的可行性,可有效提高流速仪信号采集的精度,并在单片机平台上完成了硬件设计。     

When are relative variograms useful in geostatistics?

The relative variogram has been employed as a tool for correcting a simple kind of nonstationarity, namely that in which local variance is proportional to local mean squared. In the past, this has been linked in a vague way to the lognormal distribution, although if {Z_t; t q647h31/xxlarge8712.gif" alt="isin" align="MIDDLE" BORDER="0"> D}is strongly stationary and normal over a domain D,then clearly {exp (Z_t); t q647h31/xxlarge8712.gif" alt="isin" align="MIDDLE" BORDER="0"> D}will stillbe stationary, but lognormal. The appropriate link is made in this article through a universal transformation principle. More general situations are considered, leading to the use of a q647h31/xxlarge8220.gif" alt="ldquo" align="MIDDLE" BORDER="0">scaled variogram.q647h31/xxlarge8221.gif" alt="rdquo" align="MIDDLE" BORDER="0">     

序半群的（∈,∈∨q）-模糊理想刻画

从一个新的角度研究了序半群上的（∈,∈∨q）-模糊左理想、（∈,∈∨q）-模糊右理想和（∈,∈∨q）-模糊双理想,并利用这些理想给出了正则序半群的若干刻画定理。     

The change in Sq(H) amplitude on Abnormal Quiet Days

Summary. Analysis of geomagnetic data has shown that the superposed northward magnetic field, which reduces the S _q( H ) amplitude at northern mid-latitude stations on Abnormal Quiet Days, and increases the amplitude at stations on the equatorward side of the S _q focus, builds up in amplitude over four to five days before the AQD occurs, and subsides over a similar period after the AQD. It is inferred indirectly that the azimuthal component B_y of the interplanetary magnetic field varies similarly. Data for the opposite meridian show that the imposed field reverses to a southward direction at lower latitudes. The inferred currents to account for these fields are believed to flow in the ionosphere, but to arise from magnetospheric electric fields induced by the solar wind-transported IMF.     

LDPC码及其研究进展

对低密度奇偶校验码(LDPC)的结构、编译码原理进行了介绍，并与turbo码进行了简单的比较，最后对目前LDPC码的几个研究方向及其进展作了较详细的论述，指出LDPC码具有很大的发展前景。     

Modeling Atmospheric Chemistry: Interactions between Gas-Phase Species and Liquid Cloud/Aerosol Particles

For detailed modeling of atmospheric chemistry it is necessary to consider aqueous-phase reactions in cloud droplets and deliquesced aerosol particles. Often, the gas-phase concentration is in equilibrium with the aqueous phase. Then Henryq63334v15748422m/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">s law can be used to describe the distribution between the phases provided that the Henryq63334v15748422m/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">s law coefficient is known. In some cases, thermodynamic equilibrium will not be reached and it is necessary to use kinetic expressions of the rates involved. These rates depend on diffusion constants, accommodation coefficients, Henryq63334v15748422m/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">s law coefficients, particle size distributions, and several other parameters. This review describes how these processes can be treated in computer modeling and how the necessary data can be obtained. Even though it is written primarily for use in modeling atmospheric chemistry, some parts will also be useful for waste water and pesticide control and in other areas where the distribution of chemicals between the aqueous and the gas phase is important.     

Sedimentary Characteristics of Flood-Overlake in Large Depression Basin——Taking the 4th Member, Quantou Formation, Lower Cretaceous,in Southern Songliao Basin as an Example

本文建立了一种干旱背景下坳陷湖盆全新的沉积充填模式,即“洪水—河漫湖”沉积模式.在干旱背景下,物源区的河流主要表现为季节性的洪水,大多数河流都消失在荒漠中,河水主要以地表蒸发、植被生态消耗、地下渗流、河流终端湖以及河漫湖等形式排泄,坳陷湖盆内并未形成统—大面积的汇水中心和湖相沉积.这种背景条件下,湖盆的沉积充填特征明显不同于经典的坳陷湖盆和浅水湖盆沉积.下白垩统泉头组四段沉积时期,松辽盆地具有气候干旱、地势平坦、生物单调贫乏等特征,盆地南部存在5大沉积体系及7条主要的水系.除在盆地西部古龙凹陷地区河流汇水形成小范围浅水湖泊外,在盆地南部主要为“洪水—河漫湖”的河流相沉积.坳陷湖盆“洪水—河漫湖”沉积具有以下特点:①全盆地没有统一的汇水中心,因而缺乏大面积分布的湖相和三角洲沉积;②河流表现为季节性的洪水,部分河流由于地形变缓,并未进入汇水中心,而是消失在荒漠中,河流相为盆地沉积充填的主要类型;③湖盆具有多物源、多漫湖、满盆含砂的沉积特点;④河漫湖与河流在空间分布上存在3种关系,即河流终止于河漫湖、河流穿过河漫湖、河流绕过河漫湖等.坳陷湖盆“洪水—河漫湖”是—种中—新生代陆相坳陷湖盆沉积充填的新模式,具有重要的理论和实践意义.