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21.
New observations of systematic red shifts of transition region and coronal lines obtained with SUMER (Solar Ultraviolet Measurements
of Emitted Radiation) on SOHO (the Solar and Heliospheric Observatory) are presented. With the extensive wavelength coverage
of SUMER it is possible to extend the measurements of the red shifts to much higher temperatures compared to previous instruments.
We find lines formed in the upper transition region (e.g. Ov, Sv, and Svi) to be red-shifted similar to lower temperature
lines (T ≤ 1.8 x 10-5 K). Even hotter lines such as Ovi, Neviii and Mgx show systematic red shifts on the order of 5 km s-1 in the quiet Sun. This is a new and significant result since previous measurements of the red shifts were less well constrained.
The behavior of the red shifts above T = 10-5 K has been somewhat controversial. In some earlier investigations the magnitude of the red shift has been found to increase
with temperature, reaching a maximum at T = 10-5 K and then to decrease toward higher temperatures. Thus, our results will put new constraints on theoretical models. The
measured shifts are compared to recent observations of red-shifted emission in stellar spectra obtained with the Hubble Space
Telescope. 相似文献
22.
Wilhelm K. Lemaire P. Curdt W. Schühle U. Marsch E. Poland A. I. Jordan S. D. Thomas R. J. Hassler D. M. Huber M. C. E. Vial J.-C. Kühne M. Siegmund O. H. W. Gabriel A. Timothy J. G. Grewing M. Feldman U. Hollandt J. Brekke P. 《Solar physics》1997,170(1):75-104
SUMER – the Solar Ultraviolet Measurements of the Emitted Radiation instrument on the Solar and Heliospheric Observatory (SOHO) – observed its first light on January 24, 1996, and subsequently obtained a detailed spectrum with detector B in the wavelength range from 660 to 1490 Å (in first order) inside and above the limb in the north polar coronal hole. Using detector A of the instrument, this range was later extended to 1610 Å. The second-order spectra of detectors A and B cover 330 to 805 Å and are superimposed on the first-order spectra. Many more features and areas of the Sun and their spectra have been observed since, including coronal holes, polar plumes and active regions. The atoms and ions emitting this radiation exist at temperatures below 2 × 106 K and are thus ideally suited to investigate the solar transition region where the temperature increases from chromospheric to coronal values. SUMER can also be operated in a manner such that it makes images or spectroheliograms of different sizes in selected spectral lines. A detailed line profile with spectral resolution elements between 22 and 45 mÅ is produced for each line at each spatial location along the slit. From the line width, intensity and wavelength position we are able to deduce temperature, density, and velocity of the emitting atoms and ions for each emission line and spatial element in the spectroheliogram. Because of the high spectral resolution and low noise of SUMER, we have been able to detect faint lines not previously observed and, in addition, to determine their spectral profiles. SUMER has already recorded over 2000 extreme ultraviolet emission lines and many identifications have been made on the disk and in the corona. 相似文献
23.
Markus Hassler 《Singapore journal of tropical geography》2012,33(1):124-136
Cross‐border automobile production and trade is still subject to regulations and restrictions in developed as well as developing political economic spaces. Although global production networks are within this industrial sector are significantly underpinned by political economies at national scales, macro‐scale regulation increasingly influences how and where lead firms operate within the global economy. Within this changing context, this paper outlines the recent regulatory changes in the regional political economy of Southeast Asia with the introduction of the ASEAN Free Trade Area (AFTA). Drawing on empirical evidence from the Thai industry, and how macroregional automobile production networks are established, the paper focuses on the changes of this free trade policy for component as well as vehicle trade. 相似文献
24.
Markus Hassler 《The Professional geographer》2005,57(4):530-538
This article aims to explore the role of home‐based production networks within the industrialization process of rural areas in developing countries and its impact on the labor involved. Based on the structures of the Balinese clothing industry, the article explores the organization of production, provision of production and working capital, and composition and origin of labor. This article shows that home‐based batik and embroidery clothing production in Bali is one of very few sources of income beyond agricultural work for immobile, rural labor. However, these production networks within the Balinese clothing industry are defined by weak labor relations vis‐à‐vis the clothing firm's exceptionally strong position. 相似文献
25.
The production of organic food has been regarded for a long time as being synonymous with ecological regional production systems. However, the increased production of organic food products has led to an ongoing industrialisation and also to a global spread of network structures within this segment of agriculture. This paper provides a case study of the integration of organic pepper farmers from an indigenous tribe in Kerala, India, into global agro-food networks, linking them to a German producer of organic meat products. The results of this study show that the importance of the territorial embeddedness and the abandonment of the exercise of power can be crucial for the success of global organic agro-food networks. 相似文献
26.
Lemaire P. Wilhelm K. Curdt W. SchÜle U. Marsch E. Poland A. I. Jordan S. D. Thomas R. J. Hassler D. M. Vial J. C. KÜhne M. Huber M. C. E. Siegmund O. H. W. Gabriel A. Timothy J. G. Grewing M. 《Solar physics》1997,170(1):105-122
SUMER – Solar Ultraviolet Measurements of Emitted Radiation – is not only an extreme ultraviolet (EUV) spectrometer capable of obtaining detailed spectra in the range from 500 to 1610 Å, but, using the telescope mechanisms, it also provides monochromatic images over the full solar disk and beyond, into the corona, with high spatial resolution. We report on some aspects of the observation programmes that have already led us to a new view of many aspects of the Sun, including quiet Sun, chromospheric and transition region network, coronal hole, polar plume, prominence and active region studies. After an introduction, where we compare the SUMER imaging capabilities to previous experiments in our wavelength range, we describe the results of tests performed in order to characterize and optimize the telescope under operational conditions. We find the spatial resolution to be 1.2 arc sec across the slit and 2 arc sec (2 detector pixels) along the slit. Resolution and sensitivity are adequate to provide details on the structure, physical properties, and evolution of several solar features which we then present. Finally some information is given on the data availability and the data management system. 相似文献
27.
K. Wilhelm W. Curdt E. Marsch U. Schühle P. Lemaire A. Gabriel J. -C. Vial M. Grewing M. C. E. Huber S. D. Jordan A. I. Poland R. J. Thomas M. Kühne J. G. Timothy D. M. Hassler O. H. W. Siegmund 《Solar physics》1995,162(1-2):189-231
The instrument SUMER - Solar Ultraviolet Measurements of Emitted Radiation is designed to investigate structures and associated dynamical processes occurring in the solar atmosphere, from the chromosphere through the transition region to the inner corona, over a temperature range from 104 to 2 × 106
K and above. These observations will permit detailed spectroscopic diagnostics of plasma densities and temperatures in many solar features, and will support penetrating studies of underlying physical processes, including plasma flows, turbulence and wave motions, diffusion transport processes, events associated with solar magnetic activity, atmospheric heating, and solar wind acceleration in the inner corona. Specifically, SUMER will measure profiles and intensities of EUV lines; determine Doppler shifts and line broadenings with high accuracy; provide stigmatic images of the Sun in the EUV with high spatial, spectral, and temporal resolution; and obtain monochromatic maps of the full Sun and the inner corona or selected areas thereof. SUMER will be flown on the Solar and Heliospheric Observatory (SOHO), scheduled for launch in November, 1995. This paper has been written to familiarize solar physicists with SUMER and to demonstrate some command procedures for achieving certain scientific observations. 相似文献
28.
Application of New Theories and Technology for Grouting of Dams and Foundations on Rock 总被引：4，自引：1，他引：3
Permeation grouting is used to improve rock conditions under dams and foundations. During recent decades, there has been a substantial increase of understanding of the mechanism behind grout spread in fractured rock. It is the penetrability of the grout mix and the spread in the joints which will be the governing factors for the quality of the grout curtain. The flow properties and the pressure will give the required time to achieve the quality. The empirical based refusal and completion criteria of today can be replaced by a more engineering based grouting process. An active control method has been developed in order to govern the grout spread during the grouting operation based on the new theory of spreading of grout. The concept is called the ??real time grouting control method??. The concept and the latest finding of the mechanism of spreading of the grout in the fractures of the rock mass are presented in the paper. The application of the method on two dam projects is also presented. 相似文献