检索结果-南通市图书馆

The FAST all sky HI survey(FASHI):The first release of catalog

Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 112-133页

作者： Chuan-Peng Zhang Ming Zhu Peng Jiang Cheng Cheng jing Wang Jie Wang jin-long xu Xiao-Lan Liu Nai-Ping Yu Lei Qian Haiyang Yu Mei Ai Yingjie jing Chen xu Ziming Liu Xin Guan Chun Sun Qingliang Yang Menglin Huang Qiaoli Hao FAST Collaboration Guizhou Radio Astronomical Observatory Guizhou UniversityGuiyang 550000China National Astronomical Observatories Chinese Academy of Sciences(CAS)Beijing 100101China Chinese Academy of Sciences South America Center for Astronomy National Astronomical ObservatoriesCASBeijing 100101China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China

The FAST All Sky HI survey(FASHI)was designed to cover the entire sky observable by the Five-hundred-meter Aperture Spherical radio Telescope(FAST),spanning approximately 22000 square degrees of declination between-14°and+66°,and in the frequency range of 1050-1450 MHz,with the expectation of eventually detecting more than 100000 HI *** August 2020 and June 2023,FASHI had covered more than 7600 square degrees,which is approximately 35%of the total sky observable by *** has a median detection sensitivity of around 0.76 m Jy beam-1and a spectral line velocity resolution of~6.4 km s-1at a frequency of~1.4 *** of now,a total of 41741 extragalactic HI sources have been detected in the frequency range 1305.5-1419.5 MHz,corresponding to a redshift limit of z■*** cross-matching FASHI sources with the Siena Galaxy Atlas(SGA)and the Sloan Digital Sky Survey(SDSS)catalogs,we found that 16972(40.7%)sources have spectroscopic redshifts and 10975(26.3%)sources have only photometric *** of the remaining 13794(33.0%)HI sources are located in the direction of the Galactic plane,making their optical counterparts difficult to identify due to high extinction or high contamination of Galactic stellar *** on current survey results,the FASHI survey is an unprecedented blind extragalactic H I *** has higher spectral and spatial resolution and broader coverage than the Arecibo Legacy Fast ALFA Survey(ALFALFA).When completed,FASHI will provide the largest extragalactic HI catalog and an objective view of HI content and large-scale structure in the local universe.

关键词： surveys redshifts galaxies telescope radio lines HI line

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

New HⅠ Observations Toward the NGC 5055 Galaxy Group with FAST

引用

Research in Astronomy and Astrophysics 2024年第7期 252-259页

作者： Xiao-Lan Liu Ming Zhu jin-long xu Peng Jiang Chuan-Peng Zhang Nai-Ping Yu Jun-Jie Wang Yan-Bin Yang National Astronomical Observatories Chinese Academy of Sciences Guizhou Radio Astronomical Observatory Guizhou University CAS Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of Sciences GEPI Observatoire de ParisUniversite PSLCNRS

We report a new high-sensitivity HⅠ mapping observation of the NGC 5055 galaxy group over an area of 1°.5×0°.75 with the Five-hundred-meter Aperture Spherical radio Telescope （FAST）.Our observation reveals that the warped HⅠ disk of NGC 5055 is more extended than what was previously observed by WSRT,out to23 9 （61.7 kpc）.The total HⅠ mass of NGC 5055 is determined to be～1.1×1010MΘ.We identified three HⅠ clouds with HⅠ masses of the order of～10～7MΘat the southeastern edge of the HⅠ disk,as well as a candidate high-velocity cloud with an HⅠ mass of （1.2±0.5）×10～6MΘto the north of NGC *** HⅠ content of UGCA337 is robustly detected for the first time by the FAST *** has a narrow HⅠ linewidth of W50=17.4±3.8 km s-1with a total HⅠ mass of （3.5±0.3）×10～6MΘ.Comparing the gas content and g-r color of UGCA 337 with typical low-mass dwarf galaxies,UGCA 337 appears relatively gas-poor despite its blue *** suggests that UGCA 337 may have undergone gas stripping in the *** also analyzed the possible origin of the diffuse HⅠ clouds located at the outskirts of NGC 5055,and speculate that they might be the remnant features of a merger event in the past.

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Radio Frequency Interference Mitigation and Statistics in the Spectral Observations of FAST

引用

Research in Astronomy and Astrophysics 2022年第2期22卷 173-182页

作者： Chuan-Peng Zhang jin-long xu Jie Wang Yingjie jing Ziming Liu Ming Zhu Peng Jiang National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China CAS Key Laboratory of FAST NAOCChinese Academy of SciencesBeijing 100101China College of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China

In radio astronomy,radio frequency interference(RFI)becomes more and more serious for radio observational *** RFI always influences the search and study of the interesting astronomical *** the RFI becomes an essential procedure in any survey data *** Five-hundred-meter Aperture Spherical radio Telescope(FAST)is an extremely sensitive radio *** is necessary to find out an effective and precise RFI mitigation method for FAST data *** this work,we introduce a method to mitigate the RFI in FAST spectral observation and make a statistic for the RFI using~300 h FAST *** details are as ***,according to the characteristics of FAST spectra,we propose to use the Asymmetrically Reweighted Penalized Least Squares algorithm for baseline *** test results show that it has a good ***,we flag the RFI with four strategies,which are to flag extremely strong RFI,flag long-lasting RFI,flag polarized RFI,and flag beam-combined RFI,*** test results show that all the RFI above a preset threshold could be ***,we make a statistic for the probabilities of polarized XX and YY RFI in FAST *** statistical results could tell us which frequencies are relatively *** such statistical data,we are able to avoid using such frequencies in our spectral ***,based on the~300 h FAST data,we obtained an RFI table,which is the most complete database currently for FAST.

关键词： telescopes methods:statistical site testing

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Submillimeter/millimeter observations of the high-mass star forming region IRAS 22506+5944

引用

Research in Astronomy and Astrophysics 2010年第2期10卷 151-158页

作者： jin-long xu Jun-Jie Wang National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China NAOC-TU Joint Center for Astrophysics Lhasa 850000 China

The mapping observations of CO J -- 2-1, CO J = 3- 2, 13CO J = 2-1 and 13CO J -- 3 - 2 lines in the direction of IRAS 22506＋5944 have been made. The results show that the cores in the J = 2 - i transition lines have a similar morphology to those in the J -- 3 - 2 transition lines. Bipolar molecular outflows are verified. The prior IRAS 22506＋5944 observations indicated that two IRAS sources and three H20 masers were located close to the peak position of the core. One of the IRAS sources may be the driving source of the outflows. In addition, the H20 masers may occur in relatively warm environments. The parameters of the dense core and outflow, obtained by the LTE method, indicate that IRAS 22506＋5944 is a high-mass star formation region.

关键词： ISM: jets and outflows -- ISM: kinematics and dynamics -- ISM molecules -- stars: formation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

^(12)CO J=2-1 and^(12)CO J=3-2 observations toward the high-mass protostellar candidate IRAS 20188+3928

引用

Research in Astronomy and Astrophysics 2013年第1期13卷 39-46页

作者： jin-long xu Jun-Jie Wang National Astronomical Observatories Chinese Academy of Sciences NAOC-TU Joint Center for Astrophysics

We have carried out observations of 12CO J=2-1 and 12CO J=3-2 to- ward the high-mass protostellar candidate IRAS 20188＋3928. Compared with previ- ous observations, the 12CO J=2-1 and 12CO J=3-2 lines both have asymmetric pro- files with an absorption dip. The velocity of the absorption dip is ~ 1.0 km s-1. The spectral shape may be caused by rotation. The velocity-integrated intensity map and position-velocity diagram of the 12CO J=2-1 line present an obvious bipolar com- ponent, further verifying that this region has an outflow motion. This region is also associated with an HII region, an IRAS source, and an H20 maser. The H20 maser has the velocity of 1.1 km s-1. Compared with the components of the outflow, we find that the H20 maser is not associated with the outflow. Using the large velocity gradi- ent model, we concluded that possible averaged gas densities of the blueshifted lobe and redshifted lobe are 1.0x 105 cm-3 and 2.0x 104 cm-a, while kinetic temperatures are 26.9 K and 52.9 K, respectively. Additionally, the outflow has a higher integrated intensity ratio （Ico J=3 - 2/Ico J=2 - 1）.

关键词： ISM: individual (IRAS 20188+3928) -- ISM: kinematics and dynamics-- ISM: molecules -- stars: formation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Laboratory evaluation of high-friction thin overlays for pavement preservation

引用

Frontiers of Structural and Civil Engineering 2024年第6期18卷 936-948页

作者： Ouming xu Rentao xu Lintong jin School of Highway Chang’an UniversityXi’an 710064China School of Materials Science and Engineering Chang’an UniversityXi’an 710061China

Traditional asphalt concrete(AC)and stone matrix asphalt(SMA),which are used as thin asphalt overlays,are common maintenance strategies to enhancing ride quality,skid resistance,and ***,several studies have used a novel asphalt mixture known as a high-friction thin overlay(HFTO)to improve surface ***,it remains uncertain whether the laboratory properties of HFTO differ significantly from those of conventional *** study aims to evaluate the laboratory properties of HFTO mixtures and compare them with those of AC and *** mixtures with nominal maximum size of 9.5 mm were produced in the laboratory,and performance tests were conducted,including wheel tracking test,low temperature flexural creep test,moisture susceptibility test,Cantabro Abrasion Test,Marshall Test,sand patch test,British pendulum test,and indoor tire-rollingdown *** results showed that the HFTO exhibited a lower tire/pavement noise than the AC and ***,HFTO had superior high-temperature stability,larger macro texture,and higher skid resistance in comparison to those of AC,but lower than those of ***,HFTO mixtures may be considered a suitable replacement for traditional AC mixtures in regions where skid resistance and noise reduction are concerns.

关键词： road engineering pavement maintenance high friction thin overlay performance skid resistance tire/pavement noise

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rapid and chemoselective imidation of sulfides in aqueous buffer enabled by a novel guanidine-derived N-O reagent

引用

Science China Chemistry 2024年第6期67卷 1929-1934页

作者： Hanzheng Li long xu Jiajia Dong Key Laboratory of Organofluorine Chemistry Center for Excellence in Molecular SynthesisShanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai200032China Institute of Translational Medicine National Facility for Translational Medicine(Shanghai)Shanghai Jiao Tong UniversityShanghai200240China School of Chemistry and Chemical Engineering Zhangjiang Institute for Advanced StudyShanghai Jiao Tong UniversityShanghai200240China Shanghai Artificial Intelligence Laboratory Shanghai200232China

Herein we report the facile synthesis of a series of novel N-O reagents and identify N′-di-Boc-N′′-[(mesitylsulfonyl)oxy]-guanidine as an efficient imidating *** reagent is synthetically scalable and bench-stable,yet it shows unprecedented reactivity and chemoselectivity towards S(II)in buffer/hexafluoroisopropanol(HFIP)system,to generate a new class of Nguanyl *** transformation of N-guanyl sulfilimines to N-guanyl sulfoximines provides us a chance to investigate these rarely reached compounds,which are shown to be versatile precursors to a variety of N-heterocyclic and *** work provides an addition to the tool box of both sulfur imidation and guanidine synthesis,especially for the need of rapid and selective modifications of sulfur(II)center under biocompatible conditions.

关键词： sulfur imidation N-O reagent

来源：

维普期刊数据库

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Essential oils improve nursery pigs'performance and appetite via modulation of intestinal health and microbiota

引用

Animal Nutrition 2024年第1期16卷 174-188页

作者： Bi-Chen Zhao Tian-Hao Wang Jian Chen Bai-Hao Qiu Ya-Ru xu jin-long Li College of Veterinary Medicine Northeast Agricultural UniversityHarbin150030China Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine Northeast Agricultural UniversityHarbin150030China Key Laboratory of the Provincial Education Department of Heilongjiang for Common Animal Disease Prevention and Treatment Northeast Agricultural UniversityHarbin150030China

Optimal intestinal health and functionality are essential for animal health and performance,and simultaneously intestinal nutrient transporters and intestinal peptides are also involved in appetite and feed intake control *** the potential of essential oil(EO)in improving animal performance and improving feed palatability,we hypothesized that dietary supplementation of cinnamaldehyde and carvacrol could improve performance and appetite of nursery pigs by modulating intestinal health and ***(100 mg/kg),carvacrol(100 mg/kg),and their mixtures(including 50 mg/kg cinnamaldehyde and 50 mg/kg carvacrol)were supplemented into the diets of 240 nursery pigs for 42 d,and data related to performance were ***,the influence of EO on intestinal health,appetite and gut microbiota and their correlations were *** supplementation increased(P<0.05)the body weight,average daily gain(ADG)and average daily feed intake(ADFI)of piglets,and reduced(P<0.05)diarrhea rates in nursery ***,EO increased(P<0.05)the intestinal absorption area and the abundance of tight junction proteins,and decreased(P<0.05)intestinal permeability and local *** terms of intestinal development and the mucus barrier,EO promoted intestinal development and increased(P<0.05)the number of goblet ***,we found that piglets in the EO-supplemented group had upregulated(P<0.05)levels of transporters and digestive enzymes in the intestine,which were significantly associated with daily gain and feed *** addition,EO supplementation somewhat improved appetite in nursery pigs,increased the diversity of the gut microbiome and the abundance of beneficial bacteria,and there was a correlation between altered bacterial structure and appetite-related *** findings indicate that EO is effective in promoting growth performance and nutrient absorption as well as in regulating appetite by improving intestinal health and ba

关键词： Nursery pig Essential oil Intestinal health Appetite Microbiota

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Modeling and Validation of Diamagnetic Rotor Levitated by Permanent Magnetics

引用

Chinese Journal of Mechanical Engineering 2024年第3期37卷 224-235页

作者： Yuanping xu Yue Zhang jin Zhou Chaowu jin College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

As an innovative,low-power consuming,and low-stiffness suspension approach,the diamagnetic levitation technique has attracted considerable interest because of its potential applicability in miniaturized mechanical *** foundation of a diamagnetic levitation system is mathematical modeling,which is essential for operating performance optimization and stability ***,few studies on systematic mathematical modeling have been *** this study,a systematic mathematical model for a disc-shaped diamagnetically levitated rotor on a permanent magnet array is *** on the proposed model,the magnetic field distribution characteristics,diamagnetic levitation force characteristics(i.e.,levitation height and stiffness),and optimized theoretical conditions for realizing stable levitation are *** are conducted to verify the feasibility of the proposed mathematical *** predictions and experimental results indicate that increasing the levitation height enlarges the stable ***,with a further increase in the rotor radius,the stable regions of the rotor gradually diminish and even ***,when the levitation height is fixed,a moderate rotor radius permits stable *** study proposes a mathematical modeling method for a diamagnetic levitation system that has potential applications in miniaturized mechanical systems.

关键词： Diamagnetic levitation Magnetic levitation Rotor Modeling Validation Stability

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Superior compound coatings prepared by low-temperature vanadium-nitrocarburizing duplex treatment

引用

Rare Metals 2024年第4期43卷 1828-1835页

作者： Gen jin Fang-Fang xu xun-xun Hu Yue xu School of Chemistry Beihang UniversityBeijing100191China Guobiao(Beijing)Testing and Certification Co. LtdBeijing100088China School of Materials Science and Engineering Beihang UniversityBeijing100191China

Superior compound coatings were prepared on CK45 steel surface by vanadium-nitrocarburizing duplex treatment in low-temperature salt *** this study,the microhardness,the phase constitution and the compositional distribution in the coatings prepared under different conditions were systematically *** results indicated that the reactions among activated vanadium,carbon and nitrogen atoms occurred on the steel surface,leading to the formation of compound coatings composed of outermost and compound *** mechanism for the formation of compound layer as well as the growth kinetics of the layer was also *** the duplex treatment,the wear and corrosion resistances of steel surface were significantly *** was found that the growth kinetics of compound layer obeyed the parabolic law,with the activation energy of 122.82 kJ·moL^(-1).

关键词： Vanadium-nitrocarburizing duplex treatment Compound coatings Microstructure Formation mechanism Growth kinetics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：