Suchergebnisse

Xiuyan Jade, produced in Xiuyan County, Liaoning Province, China is one of the four famous jade in China. King Jade, which is deemed the largest jade body of the world, was broken out from a hill. The local government planned to build a tourism site based on the jade culture there. The purpose of the investigation was to evaluate the stability of subsurface foundation, and the possible positions of mined-out zones to prevent the further rolling of the jade body. Cross-hole radar tomography is the key technique in the investigation. Conventional travel time and attenuation tomography based on ray tracing theory cannot provide high-resolution images because only a fraction of the measured information is used in the inversion. Full-waveform inversion (FWI) can provide high-resolution permittivity and conductivity images because it utilizes all the information provided by the radar signals. We deduce the gradient expression of the time-domain FWI with respect to the permittivity and conductivity using a method that is different from that of the previous work and realize the FWI algorithm that can simultaneously update the permittivity and conductivity by using the conjugate gradient method. Inverted results from synthetic data show that time-domain FWI can significantly improve the resolution compared with the ray-based tomogram methods. FWI can distinguish targets that are as small as one-half to one-third wavelength and the inverted physical values are closer to the real ones than those provided by the ray tracing method. We use the FWI algorithm to the field data measured at Xiuyan jade mine. Both the inverted permittivity and conductivity can comparably delineate four mined-out zones, which exhibit low-permittivity and low-conductivity characteristics. Furthermore, the locations of the interpreted mined-out zones are in good agreement with the existing mining channels recorded by geological data.

Cover -- Title Page -- Copyright Page -- Foreword -- Preface -- Acknowledgements -- Table of Contents -- List of Contributors -- Part 1: Methodologies for the Study and Utilization of Sand Dunes -- 1. A Synoptic View of Northern Hemisphere Deserts and Sand Dunes: Perceptions, Misconceptions and Distinctions -- 2. Advances in Measurement Techniques for Estimating Sand Dune Movements -- 3. A Review of the Development in the Remote Sensing of Sand Dunes -- 4. Applications of ICESat-2 Laser Altimeter Data for Sand Dunes: Morphology and Dynamics Studies -- 5. New Perspectives on the Occurrence and Characteristics of the Coastal Sand Dunes, North of Nile Delta, Egypt -- 6. Algerian Sahara Sand Dune (Western Erg) Characterization: An Experimental Study -- 7. Economic Heavy Minerals in the Coastal Area Between Burg EL-Burullus and Baltim, North of Nile Delta, Egypt -- Part 2: Dune Landscapes of China-Origins and Evolution -- 8. Formation of Dune Field Landscape in North and North-West China during Plio-Pleistocene Transition (4-2 Ma) and the Long-term Evolution -- 9. Formation, Evolution and Forcing Mechanism of Feathered Sand Dunes in the Kumtag Desert, China -- 10. Mega-Dune-Lake System in the Badain Jaran Sand Sea -- 11. Morphology, Distribution and Formation of the Nebkhas on Gobi and Desert in China -- 12. Type, Distribution, Formation and Evolution of Coastal Aeolian Dunes -- 13. High-Altitude Aeolian Desertification and Sand Dunes on the Tibetan Plateau, China -- 14. Characteristics, Dynamics, and Provenance of Sand Dunes in the Hexi Corridor, China -- Part 3: Morphology and Distribution of Dune Landscapes on the Indian Subcontinent -- 15. Dune Accumulation Chronologies from the Thar Desert, India: A Review.

"This book in two Volumes and with a FOREWORD by the renowned Professor M.A.J. Williams draws on evidence from coastal and inland regions, including desert dunes, wind-blown dust, river and lake sediments, glacial moraines, plant and animal fossils, isotope geochemistry, soils and prehistoric archaeology to better understand the genesis and development of dunes systems in selected northern hemisphere sand dunes from Asia, Africa and the Middle East regions. The collection of research papers and case studies that are presented in this book provide the reader with a wealth of information about the distribution and types of sand dunes and an insight into the complexity of sand dune formation, migration and management. Research in many countries across the northern hemisphere on Dunes, whether coastal or inland are under pressure around the world. Much of the pressure comes from human activities, and the anthropogenic disturbance, when coupled with global warming and alterations to the amount, frequency and temporal distribution of precipitation could lead to more serious management challenges in the future. There is much that we still need to find out about the origin, genesis and development of sand dunes so that they can be managed better. The difficult and complex questions being repeatedly raised can be answered only by interdisciplinary endeavours. Geomorphologists, geologists, palaeontologists, climatologists, ecologists, and others, can work together on research projects that better define the origin, evolution and development of dunes, both inland and along the coasts"--

Fritillaria hupehensis (Hubeibeimu) widely grows in the mid-western zones of China. In the present work, we investigated the physicochemical compositions, antioxidant abilities, and thermal properties of the bulbs of F. hupehensis dehydrated by heat-pump drying (HD), vacuum drying (VD), natural drying (ND), freeze drying (FD), and microwave drying (MD). Total contents of nucleosides and nucleobases in F. hupehensis flours ranged from 727.64 to 1,654.25 μg/g, and total free amino acids ranged from 88.03 to 128.21 mg/g. FD flour had high contents of total nucleosides and nucleobases, and free amino acids. MD flour had low contents of total starch, amylose, protein, nucleosides and nucleobases, and VB1 and VB2, and high levels of total phenolic content (TPC) and antioxidant abilities. Furthermore, MD flour facilitated gelatinisation, while FD flour displayed opposite trend. HD flour had high total starch content, while ND flour weakened the bitter taste due to the percentage of sweet and bitter taste of amino acids.