项目风险的一种模糊分析方法

由于影响项目的不确定因素繁多,专家们在评估一个项目的风险时,通常不得不使用一些模糊性语言.为了定量地评估项目的不确定性,提出了一种分析项目风险的新方法:用模糊集理论将这种模糊性语言定量化,即用一种简单的模糊数--三角模糊数来有效地表示项目的风险,通过比较这种三角模糊数的大小来判断风险的大小,从而评估出项目的优劣.最后,本文还认为如何准确地量化项目的不确定性仍是有待于进一步深入研究的课题.     

Characterization of a novel gravitropic mutant of morning glory, weeping2

In higher plants, gravity is a major environmental cue that governs growth orientation, a phenomenon termed gravitropism. It has been suggested that gravity also affects other aspects of morphogenesis, such as circumnutation and winding movements. Previously, we showed that these aspects of plant growth morphology require amyloplast sedimentation inside gravisensing endodermal cells. However, the molecular mechanism of the graviresponse and its relationship to circumnutation and winding remains obscure. Here, we have characterized a novel shoot gravitropic mutant of morning glory, weeping2 (we2). In the we2 mutant, the gravitropic response of the stem was absent, and hypocotyls exhibited a severely reduced gravitropic response, whereas roots showed normal gravitropism. In agreement with our previous studies, we found that we2 mutant has defects in shoot circumnutation and winding. Histological analysis showed that we2 mutant forms abnormal endodermal cells. We identified a mutation in the morning glory homolog of SHORT-ROOT (PnSHR1) that was genetically linked to the agravitropic phenotype of we2 mutant, and which may underlie the abnormal differentiation of endodermal cells in this plant. These results suggest that the phenotype of we2 mutant is due to a mutation of PnSHR1, and that PnSHR1 regulates gravimorphogenesis, including circumnutation and winding movements, in morning glory.     

Progress of super-pressure balloon development: A new “tawara” concept with improved stability

The super-pressure balloon (SPB) has been expected to be a flight vehicle that can provide a long flight duration to science. Since 1997, we have developed the SPB. Now we are at the phase of developing an SPB of a practical size. In 2009, we carried out a test flight of a pumpkin-shaped SPB with a 60,000 m³ volume. The undesirable result of this flight aroused us to resolve the deployment instability of the pumpkin-shaped SPB, which has been known as one of the most challenging issues confronting SPB development. To explore this deployment issue, in 2010, we carried out a series of ground tests. From results of these tests, we found that an SPB design modified from pumpkin, named “tawara”, can be a good candidate to greatly improve the deployment stability of the lobed SPB.     

一种新型铷汽室频标电路方案

铷汽室频标是各种原子钟中发展最为活跃的 ,由于其独特的外在及内在特点 ,在商用通信、军用车、舰、弹、机载、空间星载导航等领域得以最为广泛的应用。本文首先分析了铷汽室频标对电路部分的要求 ,其次总结了各种铷汽室频标电路方案的特点及发展趋向 ,之后提出了一种新型的电路方案 ,该方案充分利用相关技术的发展 ,克服了传统方案的缺陷 ,是实现高性能铷汽室频标—较佳选择。     

X-ray source populations in nearby star-forming galaxies

We present results on the X-ray source populations of nearby star-forming galaxies based on Chandra observations. First we discuss the monitoring campaigns on the Antennae and M82 galaxies. In both cases we find that the majority of the X-ray sources exhibit intensity and/or spectral variability. However, despite of this variability, we do not find any statistically significant variations of their X-ray luminosity functions (XLFs). We also find that the majority of the X-ray sources are associated with star-forming regions, although we do not always identify optical counterparts to the X-ray sources. Especially in the case of M82 we find that the most luminous sources are clustered in the central region of the galaxy. Finally, we present the first results from a study of a sample of nearby star-forming galaxies which form a starburst age sequence: although their XLFs to first order are represented by power-laws with consistent slopes, there is an indication for small variations, suggesting a change of their X-ray binary populations.     

宽带梳状谱发生器校准技术研究

本文介绍了利用取样示波器86100C校准带宽为50GHz的梳状谱发生器U9391F的方法。该方法用70GHz取样头测量梳状谱发生器输出端时域信号,对测量到的信号进行分析,修正取样示波器测量引入的时基误差和梳状谱发生器与取样头之间的阻抗失配,修正后得到梳状谱发生器的幅度谱和相位谱,实现了梳状谱发生器的校准,并给出幅度谱与相位谱校准结果的不确定度,分别为0.5dB和0.9°。     

基于光电脉冲的取样示波器上升时间校准实验研究

介绍了基于光电脉冲的取样示波器上升时间校准方法,设计组建了实验系统,对带宽为30GHz、50GHz取样示波器的上升时间分别进行了校准,并根据该方法建立了校准装置。对实验结果进行比较分析后,显示高斯型光电脉冲适用于具有高斯响应的取样示波器上升时间的校准。     

A statistical study of post-flare-associated CME events

We present a statistical study of post-flare-associated CMEs (PFA-CMEs) during the period from 1996 to 2010. By investigating all CMEs and X-ray flares, respectively, in the LASCO and GOES archives, we found 15875 CMEs of which masses are well measured and 25112 X-ray flares of which positions are determined from their optical counterparts. Under certain temporal and spatial criteria of these CMEs and solar flare events, 291PFA-CMEs events have been selected. Linking the flare fluxes with CME speeds of these paired events, we found that there is a reasonable positive linear relation between the CME linear speed and associated flare flux. The results show also the CME width increases as the flux of its associated solar flare increases. Besides we found that there is a fine positive linear relation between the CME mass and its width. Matching the flare fluxes with CME masses of these paired events, we find the CME mass increases as the flux of its associated solar flare increases. Finally we find the PFA-CME events are in regular more decelerated than the other CMEs.     

利用栅网控制空间等离子体环境效应模拟中的等离子体参数

通常采用ECR等离子体源产生的等离子体的温度和密度都比较大，通过附加适当目数的栅网，并在栅网上加一定的偏置电位来对等离子体参数，尤其是温度，密度进行调整，满足空间等离子体环境模拟要求，本文利用14目，25目的栅网，对已有的地面实验室空间等离子体环境进行了改进，得到了更加接近空间等离子体参数的一个地面模拟环境。     

MHD simulations and astrophysical applications

Magnetohydrodynamics is an adequate theoretical framework to study a large variety of astrophysical flows. The generation of magnetic fields by dynamo mechanisms, the development of turbulent flows or the topological change of magnetic fields by reconnection, are just a few examples. First, we describe the basic features of the MHD framework. Second, we make a brief introduction to the physical processes listed above, namely: dynamo action, MHD turbulence, and magnetic reconnection. Finally, we show the results arising from numerical simulations of these processes, for a number of configurations of astrophysical interest.     

A statistical study of solar radio Type III bursts and space weather implication

Solar radio bursts (SRBs) are the signatures of various phenomenon that happen in the solar corona and interplanetary medium (IPM). In this article, we have studied occurrence of Type III bursts and their association with the Sunspot number. This study confirms that occurrence of Type III bursts correlate well with Sunspot number. Further, using the data obtained using e-CALLISTO network, we have investigated drift rates of isolated Type III bursts and duration of the group of Type III bursts. Since Type II, Type III and Type IV bursts are signatures of solar flares and/or CMEs, we can use the radio observations to predict space weather hazards. In this article, we have discussed two events that have caused near Earth radio blackouts. Since e-CALLISTO comprises more than 152 stations at different longitudes, we can use it to monitor the radio emissions from the solar corona 24 h a day. Such observations play a crucial role in monitoring and predicting space weather hazards within few minutes to hours of time.     

Strategies for remote detection of life--DARWIN-IRSI and TPF missions.

Having selected a general definition of a living system, we wonder whether a remote detection of such systems can be made, at least in some cases. Quite fortunately, we find that this seems possible. We describe the present status of missions with this goal.     

Model calculations of middle atmospheric wind and temperature fields

The zonally-averaged circulation of the middle atmosphere between 10 and 110 km is calculated from a two-dimensional grid point model for steady solstice conditions. Using the temperatures of CIRA 72 in a diagnostic study of the vertical-meridional circulation we have investigated the influence of a latitude dependent static stability and the consequences of meridional temperature advection. In the summer mesopause region we found an area of subsidence which is located near the equatorward boundary of the noctilucent cloud region. In a self-consistent dynamical study we have assumed an empirical momentum source in the lower summer thermosphere in addition to the well-known Rayleigh friction to obtain an eastward zonal flow in this region.     

测试与校准实验室保密监督检查实践

根据新版保密资格标准中的保密检查要求,基于风险管理思想提出以风险分析为基础,以风险控制为核心的保密监督检查体系,形成基于主要风险的保密监督检查金字塔模型和各类保密检查的设计方法,指导测试与校准实验室保密监督检查工作的开展。     

一种新的飞航导弹飞行高度测量处理方法

针对飞航导弹掠海飞行试验测量和数据处理提出的高精度要求,通过对影响精度的各个环节的分析,在现有测量条件基础上,提出了航区等高参照物误差折算的飞航导弹海面高计算方法,设计了具体的测量和数据处理方案,建立了相应的精度评估模型,工程应用结果表明,由此得到的目标海面高更接近真实值,为掠海型飞航导弹海面高精确测量提供了一种新的方法。     

Study of the solar Slow Sonic,Alfvén and Fast Magnetosonic transition surfaces

In this paper we study the shape, extend and time variations of the solar wind transition surfaces using the Lima and Priest (1993) hydrodynamic model adequately adapted for the case of the solar wind flow. The transition surfaces, namely the Slow (Sonic), the Alfvén, and the Fast Magnetosonic surface, are important boundaries around the Sun and play a crucial role in the development of the solar wind and the structure of the inner heliosphere. We determine the shape and dimension of these surfaces as a function of heliographic latitude using measurements from Ulysses spacecraft, and we also study their temporal variation using data from spacecrafts at 1 AU (OMNI database). Furthermore, we establish their dependence with the solar activity, demonstrating their shape and location for the last two solar cycles. From this we noticed that the temporal variation of all transition surfaces follows the 11-year solar cycle. Finally, from the OMNI database, we have studied the temporal variation over the past 40 years of the plasma β parameter, the kinetic to magnetic and the kinetic to thermal energy ratios, at a distance of 1 AU from the Sun.     

Orbit perturbation: Evolution of a keplerian disk

The dynamical evolution of a keplerian disk of matter around a star or around a planet is a crucial point for the understanding of the formation of solar systems or for the formation of planetary rings. In this paper we will adopt a general point of view : we describe the disk by a distribution function in phase space and follow its evolution in presence of a stochastic force or binary collisions.     

采用BP算法的模糊自适应控制

在对不熟悉的过程进行模糊控制时,由于对过程的不了解,很难得到合适的控制规则.基于模糊控制器的一种解析结构,提出了将模糊控制器与神经网络相结合的方法.由神经网络对系统进行辨识,并为学习系统提供必要的信息,将控制对象视为神经网络的输出部分,采用BP算法根据神经网络提供的信息对经验规则进行修改,从而改善模糊控制系统动态响应.仿真结果表明该控制器对模型参数变化具有较好的适应能力,能够较快地修改系统的原控制规则,使对象输出较快地跟踪系统的输入.     

自由漂浮机械臂抓取翻滚目标的自适应控制策略

提出了一种自由漂浮机械臂抓取翻滚目标的自适应控制策略.抓取翻滚目标要求自由漂浮机械臂具有很强的轨迹跟踪能力,但是自由漂浮机械臂本身以及目标所存在的运动学和动力学参数不确定性使基于模型的控制器性能急剧下降,甚至变得不稳定.通过对参数的自适应逐步改善基于模型的控制器的性能,并且提出了一种新的自由漂浮机械臂关节空间自适应控制器.最后通过数值仿真对所提出的自适应控制策略进行了验证.     

Hydrodynamical evolution of AGN driven by radiation from circumnuclear starbursts

We explore the hydrodynamical evolution of dusty gas around active galactic nuclei (AGN) driven by the radiation from circumnuclear starbursts. For this purpose, we calculate the temporal equilibrium states between the radiation force by starburst regions and the gravity in galactic nuclei. As a result, we find that the equilibrium patterns between the radiation force and the gravity are roughly characterized by three types. The first is the situation where the starburst luminosity is larger than the Eddington luminosity. In this case, the dusty gas is blown out like a wind. We may detect intense infrared (IR) radiation from the starburst regions screened by blown-out dusty gas. The second is the situation when the radiation force is comparable to the gravity. In this case, the equilibrium surface surrounds the nuclear regions as well as starburst regions. Since the dusty gas absorbs UV or soft X-rays from the center and re-emits IR radiation, we may recognize it as a Seyfert 2 galaxy. The last is the situation where the starburst luminosity is small. In this case, the dusty wall of equilibrium would be built up only in the vicinity of starburst regions. The radiation from central regions is rarely obscured, because the dusty regions have only small angular extension. So, it would look like a Seyfert 1 galaxy which is characterized by intense soft X-rays. When we consider the stellar evolution in starburst regions, the starburst luminosity decreases with time. Therefore, we can recognize the above three types as time evolution; a starburst galaxy (first stage), a Seyfert 2 galaxy (second stage), and a Seyfert 1 galaxy (third stage). Note that we present here an alternative scenario for explaining the relation between Sy 1's and Sy 2's to the standard “Unified Scheme”.