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Spatial-temporal differentiation and influencing factors of rural settlements in mountainous areas: an example of Liangshan Yi Autonomous Prefecture, Southwestern China

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Journal of mountain Science 2024年第1期21卷 218-235页

作者： wang Yumeng DENG Qingchun YANG Haiqing LIU Hui YANG Feng zhao Yakai School of Geographical sciences China West Normal UniversityNanchong 637009China Sichuan Provincial Engineering Laboratory of Monitoring and Control for Soil Erosion in Dry Valleys China West Normal UniversityNanchong 637009China Liangshan Soil Erosion and Ecological Restoration in Dry Valleys Observation and Research Station Xide 616753China

Rural settlement is the basic spatial unit for compact communities in rural area. Scientific exploration of spatial-temporal differentiation and its influencing factors is the premise of spatial layout rationalization. Based on land use data of Liangshan Yi Autonomous Prefecture(hereinafter referred to as Liangshan Prefecture) in Sichuan Province, China from 1980 to 2.2., compactness index, fractal dimension, imbalance index, location entropy and the optimal parameters-based geographical detector(OPGD) model are used to analyze the spatial-temporal evolution of the morphological characteristics of rural settlements, and to explore the influence of natural geographical factors, socioeconomic factors, and policy factors on the spatial differentiation of rural settlements. The results show that:(1) From 1980 to 2.2., the rural settlements area in Liangshan Prefecture increased by 15.96 km^(2.. In space, the rural settlements are generally distributed in a local aggregation, dense in the middle and sparse around the periphery. In 2.15, the spatial density and expansion index of rural settlements reached the peak.(2. From 1980 to 2.2., the compactness index decreased from 0.7636 to 0.7496, the fractal dimension increased from 1.02.3 to 1.0314, and the fragmentation index decreased from 0.1183 to 0.1047. The spatial morphological structure of rural settlements tended to be loose, the shape contour tended to be complex, the degree of fragmentation decreased, and the spatial distribution was significantly imbalanced.(3) The results of OPGD detection in 2.15 show that the influence of each factor is slope(0.2.71) > traffic accessibility(0.2.98) > population(0.1403) > regional GDP(0.132.) > elevation(0.0987) > poverty alleviation(0). The results of OPGD detection in 2.2. show that the influence of each factor is slope(0.2.39) > traffic accessibility(0.2.98) > population(0.1432. > regional GDP(0.12.9) > poverty alleviation(0.0992. > elevation(0.093). Natural geographical facto

关键词： Rural settlements Location entropy Geographical detector Spatiotemporal differentiation Influencing factors

Rapidly growing primordial black holes as seeds of the massive high-redshift JWST Galaxies

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Science China(Physics,Mechanics & Astronomy) 2024年第10期67卷 139-146页

作者： Guan-Wen Yuan Lei Lei Yuan-Zhu wang Bo wang Yi-Ying wang Chao Chen zhao-Qiang Shen Yi-Fu Cai Yi-Zhong Fan Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Deep Space Exploration Laboratory/Department of Astronomy School of Physical SciencesUniversity of Science and Technology of ChinaHefei 230026China Jockey Club Institute for Advanced Study The Hong Kong University of Science and TechnologyHong KongChina

A group of massive galaxies at redshifts of z■7 have been recently detected by the James Webb Space Telescope(JWST),which were unexpected to form at such an early time within the standard Big Bang *** this work,we propose that this puzzle can be explained by the presence of some primordial black holes(PBHs)with a mass of~1000M_(⊙).These PBHs act as seeds for early galaxy formation with masses of~10^(8)-10^(10)M_(⊙)at high redshift,hence accounting for the JWST *** use a hierarchical Bayesian inference framework to constrain the PBH mass distribution models,and find that the Lognormal model with the M_(c)~750M_(⊙)is preferred over other *** rapidly growing BHs are expected to have strong radiation and may appear as high-redshift compact objects,similar to those recently discovered by *** we focused on PBHs in this work,the bound on the initial mass of the seed black holes remains robust even if they were formed through astrophysical channels.

关键词： primordial black hole dark matter halo black hole accretion primordial galaxies

Simultaneous detection of flare-associated kink oscillations and extreme-ultraviolet waves

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Science China(Technological sciences) 2024年第5期67卷 1592-1601页

作者： LI Dong HOU ZhenYong BAI XianYong LI Chuan FANG Matthew zhao HaiSheng wang JinCheng NING ZongJun Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing210023China Yunnan Key Laboratory of the Solar Physics and Space Science Kunming650216China School of Earth and Space sciences Peking UniversityBeijing100871China National Astronomical Observatories Chinese Academy of SciencesBeijing100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing100049China School of Astronomy and Space Science Nanjing UniversityNanjing210023China Key Laboratory of Modern Astronomy and Astrophysics Ministry of EducationNanjing UniversityNanjing210023China Columbus academy GahannaOhio43230USA Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing100049China Yunnan Observatories Chinese Academy of SciencesKunming650216China

Kink oscillations,which are frequently observed in coronal loops and prominences,are often accompanied by extreme-ultraviolet(EUV)***,much more needs to be explored regarding the causal relationships between kink oscillations and EUV *** this article,we report the simultaneous detection of kink oscillations and EUV waves that are both associated with an X2.1 flare on 2.2. March 03(SOL2.2.-03-03T17:39).The kink oscillations,which are almost perpendicular to the axes of loop-like structures,are observed in three coronal loops and one *** short loop shows in-phase oscillation within the same period of 5.2.min at three *** oscillation could be triggered by the pushing of an expanding loop and interpreted as the standing kink *** lags are found between the kink oscillations of the short loop and two long loops,suggesting that the kink wave travels in different *** kink oscillations of one long loop and the prominence are possibly driven by the disturbance of the coronal mass ejection(CME),and that of another long loop might be attributed to the interaction of the EUV *** onset time of the kink oscillation of the short loop is nearly same as the beginning of an EUV *** fact demonstrates that they are almost *** EUV wave is most likely excited by the expanding loop structure and shows two *** leading component is a fast coronal wave,and the trailing one could be due to the stretching magnetic field lines.

关键词： coronal loops solar flares solar prominence solar oscillations extreme-ultraviolet wave magnetohydrodynamic

The total column densities and fractional abundances of CH3CN, CH3OH, HCOOCH3 and 13CS in W51 cores

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Science China(Physics,Mechanics & Astronomy) 2005年第2期 32-41页

作者： PEI Chunchuan, MA Hongjun, ZENG Qin & LI Bo purple mountain {2., chinese academy of sciences, nanjing 2.0008, China

We present interferometric observations of the W51 region at 2.7 mm and 3.3 mm with the Berkeley-Illinois-Maryland Association Array. The lines of CH3CN (J = 6 – 5, K = 0,1,2.3,4), CH3OH (15-2.?151 E), HCOOCH3-A (71,6 – 61,5), HCOOCH3 -E (71,6 – 61,5) and 13CS (2.1) as well as the 2.7 mm continuum toward W51 have been observed. The derived total beam-averaged column densities NT and fractional abundances of CH3CN, CH3OH, HCOOCH3 and 13CS in W51 cores have been obtained.

关键词： massive star formation interstellar molecular lines column density fractional abundance.

AR5395: THE FLARE TRIGGER AND THE EVOLUTION OF MAGNETIC FIELDS

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天文研究与技术 1990年第4期 48-50,332页

作者： Chen Xiezhenpurple mountain {2., chinese academy of sciences, nanjing, 2.0008, China

1. A Brief Description of the Observation and Data Using a slit-jaw system attached to the multiple wavelength solar spectrograph atpurple mountain {2., four sets of high resolution data of Hαmonochrometic images about Boulder AR No.5395 were obtained during 9-16 March,1989. Comparing with the longitudinal magnetograms provided by Huairou Solar Ob-

关键词： longitudinal Solar Observation attached filaments unrelated indirectly bright posed purple

Protective benefits of HDPE board sand fences in an environment with variable wind directions on Gobi surfaces:wind tunnel study

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Journal of mountain Science 2024年第10期21卷 3353-3367页

作者： ZHANG Kai TIAN Jianjin LIU Benli zhao Yanhua ZHANG Hailong wang Zhenghui DENG Yuhui College of Civil Engineering Lanzhou Jiaotong UniversityLanzhou 730000China Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China

The Golmud-Korla Railway in the Gobi area faces operational challenges due to sand hazards,caused by strong and variable *** study addresses these challenges by conducting wind tunnel tests to evaluate the protective benefits of High Density Polyethylene(HDPE)board sand fences,focusing on their orientation relative to various wind directions(referred to as'wind angle').This study found that the size of the low-velocity zone on the leeward side of the sand fences(LSF)expanded with an increase in the wind angle(WA).At 1H(the height of the sand fence)and 2. positions on the LSF,the wind speed profiles(WSP)exhibited a segmented logarithmic growth,constrained by Z=H at varying *** efficacy of the sand fence in obstructing airflow escalated as WA *** size of the WA has a significant impact on the protective efficiency of HDPE board sand ***,compared to typical sandy surfaces,the rate of sand transport across the Gobi surface diminishes more slowly with height,attributed to the gravel's rebound *** phenomenon allows some sand particles to bypass the fences,rendering them less effective at blocking wind and trapping sand than in sandy *** paper offers scientific evidence supporting the practical use and enhancement of HDPE board sand fences in varied wind conditions.

关键词： Variable wind directions Blown sand control Wind tunnel tests HDPE board sand fences

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地外生命搜索和太阳系外的行星的发现

天文学报 2001年第3期42卷 225-239页

作者：吴光节陈道汉中国科学院云南天文台中国科学院国家天文台北京100012 中国科学院紫金山天文台

阐述地外生命搜索的意义、手段和现状 ,地外生命搜索的SETI计划及其发展 .并着重介绍太阳系外的行星系统的发现 ,它的目的、方法、成果以及未来 .太阳系外的行星系统的发现是当代天文学最时髦的、也将是未来 2.1世纪成果最丰富的研究领... 详细信息

阐述地外生命搜索的意义、手段和现状 ,地外生命搜索的SETI计划及其发展 .并着重介绍太阳系外的行星系统的发现 ,它的目的、方法、成果以及未来 .太阳系外的行星系统的发现是当代天文学最时髦的、也将是未来 2.1世纪成果最丰富的研究领域之一 .从 1 992.第一个确认了脉冲星PSR 1 2.5 7+1 2.行星系统以来 ,1 995年确认主序星 5 1Peg有一颗行星 ,至 2.0 0 1年 5月 ,已经发现了 6 0个太阳系外的行星系统 .太阳系外的行星系统的发现与地外生命搜索研究是密不可分的 .新的发现也提出了很多新的谜 .这项研究近 1 0年来发展很快 .它的研究也促进了航天学、宇宙化学、天文生物学乃至哲学等其他学科的发展 .

关键词：地外生命太阳系行星探测方法

RAMAN SPECTRA OF SEVEN INTERPLANETARY DUST PARTICLES

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空间科学学报 1992年第1期 57-62页

作者： Xu Yin-lin Yu Min(purple mountain {2., nanjing)Chang-Yun Fan(University of Arizona, USA)

The Raman Shift Spectra of seven interplanetary dust particles,U2.34 (F10),U2.34(F8),U2.2.(B1),W7074 18,W7074 C15,W7074 C3 and W7074 A7,were measured with a Spex-1403 Raman *** exciting radiations were the 488 nm and 514 nm line of a 5W argon ion *** seven spectra exhibit the 1350 and 1600 Acm-1 arbon bands,implying that the IDPS were coated with hydrocarbon and incompletely crystallized carbon,the part of which may be the residue of hydro-carbon contents in the particles after water loss by the heating during their entry into the earth’s atmosphere.A weak band structure in the 52.-610 cm-1 range could be caused by cyclosilicates,and a weak band at 2.00 cm-1 is tentatively identified as due to hydrocarbon molicules.

关键词： Interplanetary Dust Particles Raman Spectra Carbon

Two types of coumarins-specific enzymes complete the last missing steps in pyran- and furanocoumarins biosynthesis

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Acta Pharmaceutica Sinica B 2024年第2期14卷 869-880页

作者： Yucheng zhao Yuedong He Liangliang Han Libo Zhang Yuanzheng Xia Fucheng Yin Xiaobing wang Deqing zhao Sheng Xu Fei Qiao Yibei Xiao Lingyi Kong Department of Resources Science of Traditional chinese Medicines School of Traditional Chinese Pharmacyand State Key Laboratory of Natural MedicinesChina Pharmaceutical UniversityNanjing 210009China College of Bioscience and Biotechnology Hunan Agricultural UniversityChangsha 410128China Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines Department of Natural Medicinal ChemistryChina Pharmaceutical UniversityNanjing 210009China Key Laboratory of Crop Gene Resources and Germplasm Enhancement in Southern China Ministry of AgricultureTropical Crops Genetic Resources InstituteChinese Academy of Tropical Agricultural SciencesHaikou 517317China Institute of Botany Jiangsu Province and Chinese Academy of SciencesNanjing 210014China Department of Pharmacology School of Pharmacyand State Key Laboratory of Natural MedicinesChina Pharmaceutical UniversityNanjing 210009China

Pyran-and furanocoumarins are key representatives of tetrahydropyrans and tetrahydrofurans,respectively,exhibiting diverse physiological and medical ***,the biosynthetic mechanisms for their core structures remain poorly *** we combined multiomics analyses of biosynthetic enzymes in Peucedanum praeruptorum and in vitro functional verification and identified two types of key enzymes critical for pyran and furan ring biosynthesis in *** included three distinct *** prenyltransferases(PpPT1e3)responsible for the prenylation of the simple coumarin skeleton 7 into linear or angular precursors,and two novel CYP450 cyclases(PpDC and PpOC)crucial for the cyclization of the linear/angular precursors into either tetrahydropyran or tetrahydrofuran *** analyses of cyclases indicated that acid/base-assisted epoxide ring opening contributed to the enzyme-catalyzed tetrahydropyran and tetrahydrofuran ring *** possible acid/base-assisted catalytic mechanisms of the identified cyclases were theoretically investigated and assessed using site-specific *** identified two possible acidic amino acids Glu303 in PpDC and Asp301 in PpOC as vital in the catalytic *** study provides new enzymatic tools in the epoxide formation/epoxide-opening mediated cascade reaction and exemplifies how plants become chemically diverse in terms of enzyme function and catalytic process.

关键词： Tetrahydropyrans Tetrahydrofurans Baldwin rules Coumarins CYP450cyclase