Structure of the Large-Scale Vortex Motions in the Ionosphere E Region

It is shown that the dissipative-centrifugal instability (DCI) revealed earlier for large-scale two-dimension vortex motions of the neutral gas in a fast-rotating atmosphere is also possible for similar motions of a weakly ionized gas in the magnetic field when one takes into account electrodynamics forces (the induction deceleration and gyroscopic force caused by the Hall current) in the absence of dissipation. In the case of a conductive atmosphere, strictly anticyclone motion at a DCI of the neutral atmosphere could be impossible or (depending on the Hall conductivity value) it could even change to a cyclone motion. Experimental results that can be considered as a confirmation of the theoretical conclusions are presented.     

Formation of a Polarization Jet during the Expansion Phase of a Substorm: Results of Ground-Based Measurements

The ground-based polarization jet measurements at the Yakutsk ionosphere station (L= 3.0) for the years 1989–1991 (110 events) are compared with variations of the AE-index and with parameters of the local magnetic activity. It is shown that polarization jet development in the near midnight sector can occur during a period of no longer than 10 min on the expansion phase of a substorm. The formation of the polarization jet is accompanied by a specific magnetic field variation corresponding in shape to a fast passage of the Harang Discontinuity above the station. Statistical data are given on ground level observations of the polarization jet, which are close to those measured from satellites. The mean delay (averaged over the full data bank) between the onset of a substorm with AE 500 nT and the moment of the polarization jet appearance at L= 3.0 is equal to 0.5 h near midnight and to 1.0 – 1.5 h in the evening sector. Estimations show that the duration of the polarization jet formation when energetic ions are injected into the Harang Discontinuity region above the ground station can last for about 10 min, and during this time the Harang Discontinuity can be shifted to the west. This is in qualitative agreement with the described observations.     

关于北方地区住宅阳台空间的分析

从新疆地区的住宅阳台近十多年的设计和使用状况分析,根据有关空间设计的原理,提出阳台设计和改造的思路.     

关于北方地区住宅阳台空间的分析

从新疆地区的住宅阳台近十多年的设计和使用状况分析，根据有关空间设计的原理，提出阳台设计和改造的思路。     

亚太地区的战区导弹防御系统

近年来，美国加快广其“战区导弹防御系统”叮MD附划的发展步伐，并于1997年修改了1972年美苏签订的《反弹道导弹条约》（ABM），以为自己发展先进的反弹道导弹系统扫清障碍。1999年5月美同政府批准实施该计划，为此克林顿政府将在1999－2005年恢算中拨款105亿美元加快该计划的实施。从TMD系统本身来说，无论是对付射程在3500公里以内的战区弹道导弹，还是射程在8000公里以卜的远程洲际弹道导弹；无论是陆基、海么还是空基，美国都全方位加快厂反导武器的研制步伐，摆出了名为“防御”、实为威胁的逼人态势。llJ一见，美国政府正在＿L恢…     

AIDC在中南地区的应用

一、AIDC概述AIDC(ATS INTER-FACILITY GROUND/GROUND DATA COMMUNIC-ATIONS)是ICAO为亚太地区相邻的飞行管制服务区间制定的数据通信和管制移交的标准协议。在两个     

某锅炉钢结构角钢对扣箱型结构的焊接

某锅炉钢结构项目电梯井立柱采用了角钢对扣的箱型结构,此种箱形结构截面小,焊缝布置不对称,且焊缝长度较大,坡口切割变形、焊接变形难以控制,我们通过自制工装改进制作工艺解决了此类问题,满足该项目的验收要求。     

伽利略系统的频率结构和信号设计的研究

分析了伽利略系统的频率结构和信号设计、性能及干扰,阐明了伽利略系统的频率和信号设计比GPS更具优势。伽利略系统在ESa／L5和E2-L1-E1载波上,使用与GPS相同的中央频率,可提高GNSS接收机用户的互用性,因此具有更广阔的发展前景。     

蜂窝夹层结构复合材料特性及破坏模式分析

文章介绍了蜂窝夹层结构复合材料的特性,结合研制实践破坏模式做了分析,同时还叙述了损伤破坏模式类型和损伤修补要求等内容。     

蜂窝夹层结构复合材料特性及破坏模式分析

文章介绍了蜂窝夹层结构复合材料的特性，结合研制实践破坏模式做了分析，同时还叙述了损伤破坏模式类型和损伤修补要求等内容。     

The Structure of Ion Spectra in Outer Regions of the Ring Current: The November 13, 1995 Event

We present the results on variations of ion spectra in the energy range from 1 keV to 3 MeV. The spectra measured onboard the INTERBALL Tail Probe satellite on November 13, 1995, during the satellite's passage from the dipole field lines to the lines stretched into the magnetotail are analyzed. The data of the CORALL, DOK-2, and SKA-2 instruments are used to reconstruct the ion spectra. It is shown that, when the ion spectrum along the satellite trajectory is averaged over 2-min intervals, it is smooth up to geocentric distances of 6R _E. With decreasing distances, the form of the particle spectra in the region under consideration remained virtually unchanged (region from L = 11R _E down to L= 6R _E) and only insignificant variations of the energy of the spectral maxima are observed. Possible reasons for the observed regularities are discussed.     

利用外资优化廊坊地区产业结构的现状及建议

"十一五"规划指出我们要抓住国际产业转移机遇,积极有效利用外资,把利用外资同提升国内产业结构、技术水平结合起来,促进产业结构调整,加快推进工业结构优化升级.本文探讨了外商投资对廊坊地区产业结构的影响.     

利用外资优化廊坊地区产业结构的现状及建议

“十一五”规划指出我们要抓住国际产业转移机遇,积极有效利用外资,把利用外资同提升国内产业结构、技术水平结合起来,促进产业结构调整,加快推进工业结构优化升级。本文探讨了外商投资对廊坊地区产业结构的影响。     

Nonlinear Disturbances in the Ionospheric E Region under the Action of Internal Gravity Waves

We consider the influence of harmonics generated by an internal gravity wave (IGW) on the formation of nonlinear disturbances in the ionospheric E region. It is shown that the response of the lower ionosphere to the IGW propagation should be less efficient than the action of the IGW on the ionospheric F region. Nevertheless, if there are some thin layers (e.g., sporadic E layers) in the lower ionosphere, the response can be amplified; its amplitude is determined by the sharpness of the density gradient as compared with the characteristic scale of the atmosphere.     

航天器蜂窝夹层结构复合材料热变形分析

蜂窝夹层结构复合材料在航空、航天结构中已得到了广泛的应用。文章从热变形分析角度出发，对蜂窝夹层结构复合材料的热变形分析问题提出了几点看法。     

Structure of the Disturbed Magnetosphere

The quasitrapping region (QTR) at the night side of a disturbed magnetosphere in the majority of models is either absent completely or merges with the plasma sheet of the magnetosphere tail. At the same time these two regions are different both in the topology of the magnetic field and in the character of motion of charged particles. Moreover, it is the region of quasitrapping that is conjugate to the zone of auroral active forms; i.e., it can be called the auroral magnetosphere. Models of the magnetosphere in which the tail structures of the magnetic field are directly adjacent to the boundary of stable trapping (in particular, the isotropic boundary model) are based on erroneous assumptions. Our understanding of the processes of magnetosphere substorms and magnetic storms depends on a correct understanding of the magnetosphere structure.     

航天器蜂窝夹层结构复合材料热变形分析

蜂窝夹层结构复合材料在航空、航天结构中已得到了广泛的应用。文章从热变形分析角度出发,对蜂窝夹层结构复合材料的热变形分析问题提出了几点看法。     

The Fine Structure of the AKR Electromagnetic Field as Measured by the Interball-2 Satellite

The fine structure of the Auroral Kilometric Radiation (AKR) is studied using multicomponent measurements of the electric component of the electromagnetic field in the frequency band 4 kHz–1 MHz (the POLRAD experiment onboard the INTERBALL-2 satellite). Special attention is paid to the measurements near the source of the AKR: under conditions when the lower boundary of the emission range descended sufficiently low, down to the local gyrofrequency of electrons. From the analysis of the electric field structure the conclusion is drawn that the bulk of the AKR power is carried by the signal component fast variable in time and frequency (flickering component). The power of a constant component (continuum) is lower by at least an order of magnitude. During strong bursts of the AKR, the relative contribution of the flickering component increases. The spatial structure of the zone of generation has at least three characteristic scales along and across the magnetic field.     

大型挠性空间结构的分散PD控制

利用分散控制理论研究了传感器和执行机构同等配置挠性空间结构的镇定问题。文中构造了针对这种结构的分散PD控制器 ,并且给出了该PD控制器镇定空间结构的充分条件 ,最后给出了仿真验证。     

京津冀地区运河遗产游憩开发模式研究

第38届世界遗产大会上中国大运河被列入世界遗产名录。大运河的申遗成功,为推进京津冀一体化进程带来了新的契机。本文以游憩行为作为切入点,在挖掘运河的文化修养价值、地方认同价值、休闲娱乐价值、科学教育价值的基础上,探讨京津冀区域内的运河遗产保护与开发的途径。