This study constructs a preliminary inventory of landslides triggered by the M_(S) 6.8 Luding earthquake based on field investigation and human-computer interaction visual interpretation on optical satellite images.Th...This study constructs a preliminary inventory of landslides triggered by the M_(S) 6.8 Luding earthquake based on field investigation and human-computer interaction visual interpretation on optical satellite images.The results show that this earthquake triggered at least 5007 landslides,with a total landslide area of 17.36 km^(2),of which the smallest landslide area is 65 m^(2)and the largest landslide area reaches 120747 m^(2),with an average landslide area of about 3500 m^(2).The obtained landslides are concentrated in the IX intensity zone and the northeast side of the seismogenic fault,and the area density and point density of landslides are 13.8%,and 35.73 km^(-2) peaks with 2 km as the search radius.It should be noted that the number of landslides obtained in this paper will be lower than the actual situation because some areas are covered by clouds and there are no available post-earthquake remote sensing images.Based on the available post-earthquake remote sensing images,the number of landslides triggered by this earthquake is roughly estimated to be up to 10000.This study can be used to support further research on the distribution pattern and risk evaluation of the coseismic landslides in the region,and the prevention and control of landslide hazards in the seismic area.展开更多
Augmented reality(AR)displays are attracting significant attention and efforts.In this paper,we review the adopted device configurations of see-through displays,summarize the current development status and highlight f...Augmented reality(AR)displays are attracting significant attention and efforts.In this paper,we review the adopted device configurations of see-through displays,summarize the current development status and highlight future challenges in micro-displays.A brief introduction to optical gratings is presented to help understand the challenging design of grating-based waveguide for AR displays.Finally,we discuss the most recent progress in diffraction grating and its implications.展开更多
The Liupan Mountains,one of the important mountain ranges in western China,are located on the boundary between the northeastern Tibetan Plateau and the Ordos Block.The uplift history of the Liupan Mountains remains co...The Liupan Mountains,one of the important mountain ranges in western China,are located on the boundary between the northeastern Tibetan Plateau and the Ordos Block.The uplift history of the Liupan Mountains remains controversial.Loess deposits are good tracers of regional tectonic and geomorphic changes,because loess is sensitive to erosion and the formation and preservation of loess requires relatively flat highlands and relatively stable tectonic environments.We investigated the distribution of Neogene loess deposits on the western piedmont of the Liupan Mountains and examined a near-continuous loess section(Nanping section)on the piedmont alluvial highlands.Correlation of magnetic susceptibility stratigraphy with the QA-ⅠMiocene loess sequence dates this 56-m section covering the interval from~8.1 to 6.2 Ma.The lower boundary age of this section,together with previously reported Zhuanglang red clay(sand-gravel layers with intercalated loess during~9–8 Ma and near-continuous loess during~8–4.8 Ma)and Chaona red clay(~8.1–2.58 Ma),indicates that the Liupan Mountains were uplifted in the late Miocene(~9–8 Ma)and basically formed by~8 Ma,attesting to no intense mountain building since that time.In addition,based on the information from the Zhuanglang core and the QA-Ⅰsection,we infer that sizable parts of the Liupan Mountains were uplifted during the late Oligocene–early Miocene and did not experience intense uplift during~22–9 Ma.展开更多
With rapid advances in high-speed communication and computation,augmented reality(AR)and virtual reality(VR)are emerging as next-generation display platforms for deeper human-digital interactions.Nonetheless,to simult...With rapid advances in high-speed communication and computation,augmented reality(AR)and virtual reality(VR)are emerging as next-generation display platforms for deeper human-digital interactions.Nonetheless,to simultaneously match the exceptional performance of human vision and keep the near-eye display module compact and lightweight imposes unprecedented challenges on optical engineering.Fortunately,recent progress in holographic optical elements(HOEs)and lithography-enabled devices provide innovative ways to tackle these obstacles in AR and VR that are otherwise difficult with traditional optics.In this review,we begin with introducing the basic structures of AR and VR headsets,and then describing the operation principles of various HOEs and lithography-enabled devices.Their properties are analyzed in detail,including strong selectivity on wavelength and incident angle,and multiplexing ability of volume HOEs,polarization dependency and active switching of liquid crystal HOEs,device fabrication,and properties of micro-LEDs(light-emitting diodes),and large design freedoms of metasurfaces.Afterwards,we discuss how these devices help enhance the AR and VR performance,with detailed description and analysis of some state-of-the-art architectures.Finally,we cast a perspective on potential developments and research directions of these photonic devices for future AR and VR displays.展开更多
The fuzzy method is introduced to the calculation of thermal performance of refrigeration compressors. A compound model combining classical thermodynamic theory and fuzzy theory is presented and compared with a simple...The fuzzy method is introduced to the calculation of thermal performance of refrigeration compressors. A compound model combining classical thermodynamic theory and fuzzy theory is presented and compared with a simple fuzzy model without classical thermodynamic fundamentals. Case study of refrigeration compressors shows that the compound fuzzy model and the simple fuzzy model are both more efficient than the classical thermodynamic method. However, the compound fuzzy model is of better precision and adaptability.展开更多
As one of the most complete archaic human fossils,the Harbin cranium provides critical evidence for studying the diversification of the Homo genus and the origin of Homo sapiens.However,the unsystematic recovery of th...As one of the most complete archaic human fossils,the Harbin cranium provides critical evidence for studying the diversification of the Homo genus and the origin of Homo sapiens.However,the unsystematic recovery of this cranium and a long and confused history since the discovery impede its accurate dating.Here,we carried out a series of geochemical analyses,including non-destructive X-ray fluorescence(XRF),rare earth elements(REE),and the Sr isotopes,to test the reported provenance of the Harbin cranium and get better stratigraphic constraints.The results show that the Harbin cranium has very similar XRF element distribution patterns,REE concentration patterns,and Sr isotopic compositions to those of the Middle Pleistocene-Holocene mammalian and human fossils recently recovered from the Harbin area.The sediments adhered in the nasal cavity of the Harbin cranium have a 87Sr/86Sr ratio of 0.711898,falling in the variation range measured in a core drilled near the Dongjiang Bridge,where the cranium was discovered during its reconstruction.The regional stratigraphic correlations indicate that the Harbin cranium was probably from the upper part of the Upper Huangshan Formation of the Harbin area,which has an optically stimulated luminescence dating constraint between 138 and 309 ka.U-series disequilibrium dating(n=10)directly on the cranium suggests that the cranium is older than 146 ka.The multiple lines of evidence from our experiments consistently support the theory that the Harbin cranium is from the late Middle Pleistocene of the Harbin area.Our study also shows that geochemical approaches can provide reliable evidence for locating and dating unsystematically recovered human fossils,and potentially can be applied to other human fossils without clear provenance and stratigraphy records.展开更多
INTRODUCTION Glaucoma is a chronic progressive neurodegenerative disease and exhibits heterogeneity, polygenic inheritance, and incomplete penetrance. Primary open-angle glaucoma （POAG） is the most common form of gl...INTRODUCTION Glaucoma is a chronic progressive neurodegenerative disease and exhibits heterogeneity, polygenic inheritance, and incomplete penetrance. Primary open-angle glaucoma （POAG） is the most common form of glaucoma. Although the underlying etiology of POAG is unknown, there is evidence that genetic mutations are closely associated with this disease, Among myocilin （MYOC） mutations, Pro370Leu （P370L） is responsible for one of the most severe glaucoma phenotypes, However, the function of MYOC protein is still not well understood.展开更多
基金the National Natural Science Foundation of China(42077259).
文摘This study constructs a preliminary inventory of landslides triggered by the M_(S) 6.8 Luding earthquake based on field investigation and human-computer interaction visual interpretation on optical satellite images.The results show that this earthquake triggered at least 5007 landslides,with a total landslide area of 17.36 km^(2),of which the smallest landslide area is 65 m^(2)and the largest landslide area reaches 120747 m^(2),with an average landslide area of about 3500 m^(2).The obtained landslides are concentrated in the IX intensity zone and the northeast side of the seismogenic fault,and the area density and point density of landslides are 13.8%,and 35.73 km^(-2) peaks with 2 km as the search radius.It should be noted that the number of landslides obtained in this paper will be lower than the actual situation because some areas are covered by clouds and there are no available post-earthquake remote sensing images.Based on the available post-earthquake remote sensing images,the number of landslides triggered by this earthquake is roughly estimated to be up to 10000.This study can be used to support further research on the distribution pattern and risk evaluation of the coseismic landslides in the region,and the prevention and control of landslide hazards in the seismic area.
基金Air Force Office of Scientific Research(FA9550-14-1-0279)Goertek Electronics.
文摘Augmented reality(AR)displays are attracting significant attention and efforts.In this paper,we review the adopted device configurations of see-through displays,summarize the current development status and highlight future challenges in micro-displays.A brief introduction to optical gratings is presented to help understand the challenging design of grating-based waveguide for AR displays.Finally,we discuss the most recent progress in diffraction grating and its implications.
基金supported by the National Natural Science Foundation of China(Grant No.42488201)the Strategy Priority Research Program(Category B)of Chinese Academy of Sciences(Grant No.XDB0710000)。
文摘The Liupan Mountains,one of the important mountain ranges in western China,are located on the boundary between the northeastern Tibetan Plateau and the Ordos Block.The uplift history of the Liupan Mountains remains controversial.Loess deposits are good tracers of regional tectonic and geomorphic changes,because loess is sensitive to erosion and the formation and preservation of loess requires relatively flat highlands and relatively stable tectonic environments.We investigated the distribution of Neogene loess deposits on the western piedmont of the Liupan Mountains and examined a near-continuous loess section(Nanping section)on the piedmont alluvial highlands.Correlation of magnetic susceptibility stratigraphy with the QA-ⅠMiocene loess sequence dates this 56-m section covering the interval from~8.1 to 6.2 Ma.The lower boundary age of this section,together with previously reported Zhuanglang red clay(sand-gravel layers with intercalated loess during~9–8 Ma and near-continuous loess during~8–4.8 Ma)and Chaona red clay(~8.1–2.58 Ma),indicates that the Liupan Mountains were uplifted in the late Miocene(~9–8 Ma)and basically formed by~8 Ma,attesting to no intense mountain building since that time.In addition,based on the information from the Zhuanglang core and the QA-Ⅰsection,we infer that sizable parts of the Liupan Mountains were uplifted during the late Oligocene–early Miocene and did not experience intense uplift during~22–9 Ma.
基金The authors are indebted to Goertek Electronics for the financial support and Guanjun Tan for helpful discussions.
文摘With rapid advances in high-speed communication and computation,augmented reality(AR)and virtual reality(VR)are emerging as next-generation display platforms for deeper human-digital interactions.Nonetheless,to simultaneously match the exceptional performance of human vision and keep the near-eye display module compact and lightweight imposes unprecedented challenges on optical engineering.Fortunately,recent progress in holographic optical elements(HOEs)and lithography-enabled devices provide innovative ways to tackle these obstacles in AR and VR that are otherwise difficult with traditional optics.In this review,we begin with introducing the basic structures of AR and VR headsets,and then describing the operation principles of various HOEs and lithography-enabled devices.Their properties are analyzed in detail,including strong selectivity on wavelength and incident angle,and multiplexing ability of volume HOEs,polarization dependency and active switching of liquid crystal HOEs,device fabrication,and properties of micro-LEDs(light-emitting diodes),and large design freedoms of metasurfaces.Afterwards,we discuss how these devices help enhance the AR and VR performance,with detailed description and analysis of some state-of-the-art architectures.Finally,we cast a perspective on potential developments and research directions of these photonic devices for future AR and VR displays.
文摘The fuzzy method is introduced to the calculation of thermal performance of refrigeration compressors. A compound model combining classical thermodynamic theory and fuzzy theory is presented and compared with a simple fuzzy model without classical thermodynamic fundamentals. Case study of refrigeration compressors shows that the compound fuzzy model and the simple fuzzy model are both more efficient than the classical thermodynamic method. However, the compound fuzzy model is of better precision and adaptability.
基金This project has been supported by the National Natural Science Foundation of China(41977380,41877430,41842039,41625005,41888101,41988101)the Strategic Priority Research Program of Chinese Academy of Sciences(CAS XDB26030400,XDB26030300,XDA20070203,XDA19050100)+3 种基金the People’s Government of Hebei Province(Z20177187)the China Geological Survey(DD20190601)the Science Foundation of Hebei GEO University(TS2017-001)the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0705)。
文摘As one of the most complete archaic human fossils,the Harbin cranium provides critical evidence for studying the diversification of the Homo genus and the origin of Homo sapiens.However,the unsystematic recovery of this cranium and a long and confused history since the discovery impede its accurate dating.Here,we carried out a series of geochemical analyses,including non-destructive X-ray fluorescence(XRF),rare earth elements(REE),and the Sr isotopes,to test the reported provenance of the Harbin cranium and get better stratigraphic constraints.The results show that the Harbin cranium has very similar XRF element distribution patterns,REE concentration patterns,and Sr isotopic compositions to those of the Middle Pleistocene-Holocene mammalian and human fossils recently recovered from the Harbin area.The sediments adhered in the nasal cavity of the Harbin cranium have a 87Sr/86Sr ratio of 0.711898,falling in the variation range measured in a core drilled near the Dongjiang Bridge,where the cranium was discovered during its reconstruction.The regional stratigraphic correlations indicate that the Harbin cranium was probably from the upper part of the Upper Huangshan Formation of the Harbin area,which has an optically stimulated luminescence dating constraint between 138 and 309 ka.U-series disequilibrium dating(n=10)directly on the cranium suggests that the cranium is older than 146 ka.The multiple lines of evidence from our experiments consistently support the theory that the Harbin cranium is from the late Middle Pleistocene of the Harbin area.Our study also shows that geochemical approaches can provide reliable evidence for locating and dating unsystematically recovered human fossils,and potentially can be applied to other human fossils without clear provenance and stratigraphy records.
基金The work was supported by a grant from Project of Science Foundation of Mudanjiang （No. G2012s0028）.
文摘INTRODUCTION Glaucoma is a chronic progressive neurodegenerative disease and exhibits heterogeneity, polygenic inheritance, and incomplete penetrance. Primary open-angle glaucoma （POAG） is the most common form of glaucoma. Although the underlying etiology of POAG is unknown, there is evidence that genetic mutations are closely associated with this disease, Among myocilin （MYOC） mutations, Pro370Leu （P370L） is responsible for one of the most severe glaucoma phenotypes, However, the function of MYOC protein is still not well understood.
