期刊文献+
共找到23篇文章
< 1 2 >
每页显示 20 50 100
VIRGO星系团的视向速度成员研究 被引量:1
1
作者 赵君亮 潘容士 +1 位作者 黄松年 何燕萍 《天体物理学报》 CSCD 1990年第4期315-322,共8页
本文利用Virgo星系团天区572个星系的视向速度观测资料,按最大似然原理确定了434个成员星系。平均日心速度1247±37公里每秒,视向速度弥散度752±27公里·每秒。分析表明,尽管室女团是一个有次团结构的近距星系团,仍然可以... 本文利用Virgo星系团天区572个星系的视向速度观测资料,按最大似然原理确定了434个成员星系。平均日心速度1247±37公里每秒,视向速度弥散度752±27公里·每秒。分析表明,尽管室女团是一个有次团结构的近距星系团,仍然可以合理地用正态分布来作为成员星系观测视向速度分布的一级近似。另外,团内不同类型的星系看来有着不同的分布,而晚型星系可能仍然处于内落阶段。 展开更多
关键词 星系团 视向 速度 virgo
下载PDF
Virgo星系团内次结构的特征尺度
2
作者 邵正义 赵君亮 《天体物理学报》 CSCD 1999年第1期1-7,共7页
在小波分析的基础上,用峰值计数法考察了Virgo团天区的结构与次结构.在Virgo团典型的双峰结构下面,发现还有180’和120’两个明显的次结构的特征尺度.该结果有力地支持了等级式的成团模式.与之对应的波长下的小波... 在小波分析的基础上,用峰值计数法考察了Virgo团天区的结构与次结构.在Virgo团典型的双峰结构下面,发现还有180’和120’两个明显的次结构的特征尺度.该结果有力地支持了等级式的成团模式.与之对应的波长下的小波强度分布清楚地显示了Virgo团丰富的次结构及其分布情况,从中还发现了两个新的较小的次结构。 展开更多
关键词 星系团 小波分析 次结构 virgo星团 尺度
下载PDF
On Gravitational Waves: Did We Simply Detect the Gravitational Effect of the Sun on the Photons Moving in the Cavity of Interferometers LIGO and VIRGO? 被引量:1
3
作者 Alexandre Chaloum Elbeze 《Journal of Modern Physics》 2018年第6期1281-1290,共10页
On September 14, 2015 09:50:45 UTC, the two laser interferometers of the LIGO program simultaneously observed a first gravitational wave signal called GW150914. With the commissioning of the VIRGO interferometer in 20... On September 14, 2015 09:50:45 UTC, the two laser interferometers of the LIGO program simultaneously observed a first gravitational wave signal called GW150914. With the commissioning of the VIRGO interferometer in 2017, two other detections, GW170814 and GW170817, were observed and their positions given accurately by LIGO and VIRGO. In this article, I argue that the photons circulating in the cavities of the three interferometers of LIGO and VIRGO were sensitive to the field of attraction of the planets of our Solar System and more particularly to that of the Sun, and would not be due to a coalescence of black hole or neutron stars. The shape of the signals obtained by my interaction model (called GEAR) between the photons in the interferometer cavity and the gravitational field of the Sun is very similar to that of a compact binary coalescence, identical to those obtained by general relativity. Solving the equations of GEAR also gives the exact positions and pseudo-date of the coalescences of all the LIGO and VIRGO detections detected so far, and probably those that will come at the end of 2018 and beyond. 展开更多
关键词 GRAVITATIONAL Energy Absorber Reactor GEAR INTERFEROMETER LIGO INTERFEROMETER virgo Law of Gravitation GRAVITATIONAL Waves Expanding Universe Localization of BLACK-HOLE GEAR Model
下载PDF
Virgo星系团的Virial质量和运动学分析
4
作者 赵君亮 潘容士 何燕萍 《天体物理学报》 CSCD 1992年第2期107-113,共7页
本文利用由Binggeli、Sandage和Tammann提供的Virgo团天区星系视向速度所确定的6°核区域的352个成员星系,得出团的Virial质量为μv=2.7×10^(14)μ。总光度L_B=2.0×10^(12)L,质光比μv/L_B=136,以及光度质量μ_L=4.1×... 本文利用由Binggeli、Sandage和Tammann提供的Virgo团天区星系视向速度所确定的6°核区域的352个成员星系,得出团的Virial质量为μv=2.7×10^(14)μ。总光度L_B=2.0×10^(12)L,质光比μv/L_B=136,以及光度质量μ_L=4.1×10^(13)μ,Virgo团有着和Coma团类似的速度弥散度轮廓,近团中心部分的星系速度弥散度有减小的趋势。团星系呈现明显的形态分层,早型星系较之晚型星系明显向团中心聚集,速度弥散度较小(615:827公里·秒^(-1))。分析表明,Virgo团所经历的动力学演化过程很短,质量分层效应很不显著,是一个年轻的不规则星系团。 展开更多
关键词 室女星系团 Virial质量 运动学
下载PDF
The Distances of Subclusters in the Virgo Area
5
作者 Shao Z. Y. (Shanghai Astronomical Observatory, The Chinese Academy of Sciences, 80 Nandan RD. Shanghai 200030, China) (E-mail: zyshao center. shao. ac. cn) 《天文研究与技术》 CSCD 1999年第S1期260-263,共4页
By using the Mixture Model and radial velocity data from CfA redshift catalogue, we resolve the substructures of the Virgo cluster. Distances of three main subclusters are determined by the Tully-Fisher galaxies, they... By using the Mixture Model and radial velocity data from CfA redshift catalogue, we resolve the substructures of the Virgo cluster. Distances of three main subclusters are determined by the Tully-Fisher galaxies, they are 18.0±1.3Mpc, 25.0±2 3Mpc and 30.9±3.1Mpc respectively, which implicate that they are independent clusters, and the Virgo area has a significant depth in the line-of -sight direction. 展开更多
关键词 CLUSTER of GALAXIES virgo SUBSTRUCTURE DISTANCE
下载PDF
Virgo Cluster Membership Based on <i>K</i>-Means Algorithm
6
作者 Ibrahim Mohamed Selim Passent Elkafrawy +1 位作者 Walid Dabour Mohamed Eassa 《International Journal of Astronomy and Astrophysics》 2020年第1期1-10,共10页
The Virgo cluster of galaxies is of great importance to study the development of the universe due to its close distance from the earth as well as being the center of the local super cluster. The problem that faces Vir... The Virgo cluster of galaxies is of great importance to study the development of the universe due to its close distance from the earth as well as being the center of the local super cluster. The problem that faces Virgo cluster studies is that it shares the same right ascension (RA) and Declination (DEC) ranges with large number of background as well as foreground galaxies. This study aims to geometrically and statistically estimate Virgo cluster membership. The study employs Virgo cluster data, prepared by Harvard University. The radial velocity (RV) data of the Virgo cluster were treated and employed in exchange of missing galaxies’ third dimension, taking advantage of their proportionality. The data were treated by K-means algorithm, using Matlab 2014, and visual and logical exclusion of extremity galaxies to determine the rational center of the Virgo galaxies cluster. Results were presented, compared and discussed. Finally distances of galaxies from the Virgo cluster center were employed along with normal probability distribution characteristics to identify the most probable Virgo cluster members from the range of Virgo cluster of galaxies. The results showed that out of 17,466 objects surveyed in Virgo galaxy range, only few of galaxies were estimated to be genuine Virgo members. 展开更多
关键词 virgo CLUSTER K-MEANS NORMAL Distribution
下载PDF
Virgo星系团天区星系的成员概率
7
作者 赵君亮 潘容士 何燕萍 《中国科学院上海天文台年刊》 1991年第12期40-52,共13页
本文给出了利用视向速度、按最大似然原理对Virgo星系团天区572个星系所作的成员判别的具体结果,并对有关问题作了简要的讨论。
关键词 virgo星系团 成员概率 分布参数 视向速度 最大似然原理
下载PDF
安徽省鸟类分布新纪录——红喉潜鸟(Gavia stellata)和蓑羽鹤(Grus virgo) 被引量:1
8
作者 张财文 马号号 +4 位作者 朱志 夏家振 虞磊 李春林 张保卫 《安徽大学学报(自然科学版)》 CAS 北大核心 2021年第2期99-101,共3页
2019年12月安徽省岳西县来榜镇森林公安在其辖区(116°11′46.94″E,30°55′21.99″N,海拔416 m)救助到一只红喉潜鸟(Gavia stellata);2020年12月笔者在合肥市牛角大圩(117°16′2.42″E,31°40′1.15″N,海拔10 m)发... 2019年12月安徽省岳西县来榜镇森林公安在其辖区(116°11′46.94″E,30°55′21.99″N,海拔416 m)救助到一只红喉潜鸟(Gavia stellata);2020年12月笔者在合肥市牛角大圩(117°16′2.42″E,31°40′1.15″N,海拔10 m)发现一只蓑羽鹤(Grus virgo)并拍摄了照片.通过相关专著和文献鉴定核实,确定这2种鸟类均为安徽省鸟类分布新纪录. 展开更多
关键词 安徽省 分布新纪录 红喉潜鸟 蓑羽鹤
下载PDF
Mar.Quis Virgo Series多声道音箱
9
《家庭影院技术》 2002年第10期7-7,共1页
关键词 virgo SERIES 多声道音箱 Mar.Quis公司
原文传递
引力波的世纪追寻(三):后续发现、历史和未来 被引量:1
10
作者 施郁 《科学》 2018年第5期26-31,共6页
以通俗易懂但力求准确的方式,介绍了引力波首次直接探测之后的其他引力波发现,特别是VIRGO与LIGO首次共同探测到的引力波事件,以及中子星并合导致的引力波,还讨论了LIGO的发展历史和其他引力波探测计划。最后作者对引力波探测的成功发... 以通俗易懂但力求准确的方式,介绍了引力波首次直接探测之后的其他引力波发现,特别是VIRGO与LIGO首次共同探测到的引力波事件,以及中子星并合导致的引力波,还讨论了LIGO的发展历史和其他引力波探测计划。最后作者对引力波探测的成功发表了个人评论。继首次探测到引力波GW150914,LIGO又探测到几次引力波事件^([1])。 展开更多
关键词 引力波 相对论 LIGO virgo 黑洞 中子星
下载PDF
笼养蓑羽鹤繁殖期的行为时间分配 被引量:8
11
作者 周宏力 田秀华 粟海军 《东北林业大学学报》 CAS CSCD 北大核心 2004年第4期70-72,共3页
通过对两组笼养蓑羽鹤 (Anthropoidesvirgo)繁殖期行为时间分配的初步观察表明 :笼养蓑羽鹤繁殖期行为呈日节律变化 ,各种行为所占比例依次为休息行为 31.7%、取食 2 4 .0 %、理羽 17.4 %、游走 12 .5 %、警戒 9.4 %、繁殖5 .0 %。繁殖... 通过对两组笼养蓑羽鹤 (Anthropoidesvirgo)繁殖期行为时间分配的初步观察表明 :笼养蓑羽鹤繁殖期行为呈日节律变化 ,各种行为所占比例依次为休息行为 31.7%、取食 2 4 .0 %、理羽 17.4 %、游走 12 .5 %、警戒 9.4 %、繁殖5 .0 %。繁殖各期行为时间分配存在显著差异 ,繁殖后期行为时间分配受中期繁殖活动影响 ;繁殖期行为时间分配的性别差异总体不显著 ,温度和天气因素对笼养蓑羽鹤繁殖期的时间分配具显著影响。笼养蓑羽鹤繁殖期的行为时间分配与野生鹤类有较大差别 ,呈现出蓑羽鹤对笼养条件下适应环境因子变化的综合表现。 展开更多
关键词 笼养 蓑羽鹤 繁殖期 行为 时间分配
下载PDF
Barbara Longhi of Ravenna:A Devotional Self-Portrait 被引量:1
12
作者 Liana De Girolami Cheney 《Journal of Literature and Art Studies》 2022年第1期17-37,共21页
From the variety of types of portraiture,there evolved the imaging of a self-portrait as we see in Saint Catherine of Alexandria by Barbara Longhi of Ravenna(1552-1638).The self-portrait is a unique work of art,an int... From the variety of types of portraiture,there evolved the imaging of a self-portrait as we see in Saint Catherine of Alexandria by Barbara Longhi of Ravenna(1552-1638).The self-portrait is a unique work of art,an intimate record of a sitter’s personality.It is an acknowledgment of worth,an exercise in technique,and a designator of era,style,and likeness.The self-portrait can be a study in expression,an impersonation of a virtue,or a document in a history of aging.As William Shakespeare noted in Hamlet,“[The self-portrait is]to show virtue her own feature,scorn her own image,and the very age and body of the time his form and pressure.”In the sixteenth-century in Italy,artists often included themselves or their self-portraits in religious and secular scenes as a type of signature,as seen in the paintings of the Longhi family.In their many depictions of Saint Catherine of Alexandria,the Longhis composed two types of such images:a single-solo-image of the saint;and also her presence in a group with saints-a theme known as holy conversation.In her paintings,Barbara Longhi preferred to depict the solo image of Saint Catherine of Alexandria,using herself as a model for the figure of the saint or as a muse impersonating or personifying the saint’s virgo virtue.This essay is composed of two parts:(1)a brief explanation of the meaning of self-portraits in sixteenth-century Italy;and(2)a study of Barbara Longhi’s self-portraits as Saint Catherine of Alexandria. 展开更多
关键词 Barbara Longhi Ravenna Saint Catherine of Alexandria SELF-PORTRAIT PERSONIFICATION mirror virgo Christian symbolism MANNERISM Tridentine Reform
下载PDF
Barbara Longhi’s Saint Agnes of Rome:Iconic Images of Purity and Virtue 被引量:1
13
作者 Liana De Girolami Cheney 《Cultural and Religious Studies》 2022年第3期115-136,共22页
Barbara Longhi of Ravenna(1552-1638)enjoyed creating small devotional paintings depicting holy saints,in particular Saint Agnes(c.291-304).This saint’s life and martyrdom was recorded by the Bishop of Milan,Saint Amb... Barbara Longhi of Ravenna(1552-1638)enjoyed creating small devotional paintings depicting holy saints,in particular Saint Agnes(c.291-304).This saint’s life and martyrdom was recorded by the Bishop of Milan,Saint Ambrose(339-397),a Doctor of the Church and theologian,in his book Concerning Virgins(374)and by Jacobus de Voragine,the Archbishop of Genoa,in his Golden Legend(Legenda Aurea,1275).The saint’s story continues to be imaged and recounted to the present day because she is an icon of a pure and virtuous adolescent female.Barbara Longhi,along with her father,Luca Longhi(1507-1580),painted several versions of Saint Agnes.In their many depictions they composed two types of images:a single-solo-image of the saint;and her presence in a group of saints-a theme known as holy conversation.In her paintings of Saint Agnes,however,Barbara Longhi preferred to depict the solo image of the saint as virgo,a young maiden of virtue.This essay is composed of two parts:(1)an account of the life and martyrdom of Saint Agnes;and(2)an iconographical interpretation of Barbara Longhi’s Saint Agnes of Rome. 展开更多
关键词 Barbara and Luca Longhi Saint Agnes virgo Christian symbolism MANNERISM Counter-Reformation Movement Pre-Raphaelite Movement
下载PDF
内蒙古科尔沁草原山区绵羊胰脏吸虫和双腔吸虫的病原生物学研究
14
作者 唐崇惕 崔贵文 顾嘉寿 《武夷科学》 1992年第1期173-180,共8页
关于内蒙古科尔沁草原大草甸型草场上牛羊的胰脏吸虫病及双腔吸虫病的病原生物学及流行病学,作者经10多年的研究考察均已阐明(唐崇惕、崔贵文等,1979、1980、1983_a、1983_b、1985等)。本文报道对科尔沁草原山区环境中绵羊此二类吸虫病... 关于内蒙古科尔沁草原大草甸型草场上牛羊的胰脏吸虫病及双腔吸虫病的病原生物学及流行病学,作者经10多年的研究考察均已阐明(唐崇惕、崔贵文等,1979、1980、1983_a、1983_b、1985等)。本文报道对科尔沁草原山区环境中绵羊此二类吸虫病的病原生物学问题考察的结果。胰脏吸虫是胰阔盘吸虫虫种,双腔吸虫是中华双腔吸虫。它们的中间宿主种类及二吸虫的各幼虫期亦经观察。 展开更多
关键词 胰阔盘吸虫 中华双腔吸虫 枝小丽螺 中华草螽 内蒙古
下载PDF
The Nonvelocity Cosmological Spectral Shift
15
作者 Paul A. LaViolette 《International Journal of Astronomy and Astrophysics》 2021年第2期232-251,共20页
Beginning from the premise that the universe is static, and that the cosmological redshift is due to a nonconservative tired light effect, the following examines evidence supporting the prediction that photons will pr... Beginning from the premise that the universe is static, and that the cosmological redshift is due to a nonconservative tired light effect, the following examines evidence supporting the prediction that photons will progressively blueshift when transiting through the gravity wells of galaxies, galaxy clusters, and superclusters. The presence of such a nonvelocity blueshift effect is seen to make a substantial contribution to Virgo cluster galaxy spectra, sufficient to dramatically decrease the cluster’s velocity dispersion and assessed virial mass and eliminate the need to assume the presence of large quantities of dark matter. The effect is also shown to account for the Fingers-of-God effect and Kaiser pancaking effect seen when the spectra of cluster galaxies are plotted in redshift space. The opposite effect, excessive redshifting of photons passing through cosmic voids is able to explain void elongation in redshift space, and also the subnormal luminosity of void galaxies. The proposed cosmological blueshifting phenomenon also explains the downturn of the slope of the Hubble Flow in the vicinity of the Local Group which projects a negative apparent velocity for photons propagating near the Milky Way. It also offers an explanation for the blueshift of the Andromeda galaxy spectra and for Arp’s findings that the spectra of primary galaxies in a cluster tend to be blueshifted relative to their companion galaxies. These photon energy phenomena are anticipated by the physics of subquantum kinetics which predicts that photons traversing long distances through intergalactic space should undergo nonconservative tired-light redshifting, and that photons passing through gravity potential wells should undergo progressive blueshifting. The latter effect may be visualized as a negative nonvelocity Hubble constant. 展开更多
关键词 Fingers-of-God Effect Kaiser Effect virgo Cluster Dark Matter Cosmic Voids Hubble Flow Local Group Hubble Constant Nonvelocity Spectral Shifts Cosmological Redshift Subquantum Kinetics
下载PDF
巴基斯坦北方南部地区狩猎活动对鹤类的影响(英文)
16
作者 Farzana PERVEEN Hafeez Ullah KHAN 《Chinese Birds》 2010年第4期244-250,共7页
我们研究了巴基斯坦北方南部两个地区的狩猎活动对蓑羽鹤(Anthropoides virgo)和灰鹤(Grus grus)的影响。数据主要来自于野外调查、访谈及问卷调查。于2008年秋季和2009年春季分别调查了165个和85个狩猎营地。这些营地的大部分狩猎者持... 我们研究了巴基斯坦北方南部两个地区的狩猎活动对蓑羽鹤(Anthropoides virgo)和灰鹤(Grus grus)的影响。数据主要来自于野外调查、访谈及问卷调查。于2008年秋季和2009年春季分别调查了165个和85个狩猎营地。这些营地的大部分狩猎者持有野生动物狩猎许可证且狩猎活动是以休闲为目的。根据我们的调查,由于受到过度狩猎、自然栖息地的破坏、人类活动及地理因素的影响,这两种鹤在该地区的种群数量正逐渐下降。为此,我们提出了应对策略以保护这两种鹤。 展开更多
关键词 蓑羽鹤(Anthropoides virgo) 灰鹤(Grus grus) 狩猎 保护 巴基斯坦北方
下载PDF
室女团盘星系自转向量的分布Ⅰ.室女天区310个盘星系的表
17
作者 胡佛兴 吴国祥 苏洪钧 《紫金山天文台台刊》 北大核心 1993年第2期65-94,共30页
为进一步研究室女星系团盘星系自转向量的分布,本文编制了该天区有UGC发表的方位角或直径数据的310个盘星系的表(81个S0系,229个S+Irr系),其中有UGC发表的方位角的星系为245个(67个S0系,178个S+Irr系)。对能证认身份的所有星系的星系云... 为进一步研究室女星系团盘星系自转向量的分布,本文编制了该天区有UGC发表的方位角或直径数据的310个盘星系的表(81个S0系,229个S+Irr系),其中有UGC发表的方位角的星系为245个(67个S0系,178个S+Irr系)。对能证认身份的所有星系的星系云,群归属均已在表中注明。本文还讨论了表列星系的一些基本统计特征,为室女团盘系自转向量分布的研究提供了迄今为止可能是最大的,3组完整的代表性样品。 展开更多
关键词 星系团 室女团 星系自转向量
下载PDF
暖肝煎治疗急证
18
作者 赖炳琴 《实用中医内科杂志》 2013年第1期119-119,共1页
暖肝煎出自《景岳全书》,由当归、枸杞子、小茴香、肉桂、乌药、沉香、茯苓及生姜组成,方中当归、枸杞子温补肝肾,肉桂、小茴香温肾散寒,乌药、沉香行气止痛,茯苓渗湿健脾,生姜和胃散寒。笔者运用暖肝煎化裁治疗输尿管结石、室女痛经,... 暖肝煎出自《景岳全书》,由当归、枸杞子、小茴香、肉桂、乌药、沉香、茯苓及生姜组成,方中当归、枸杞子温补肝肾,肉桂、小茴香温肾散寒,乌药、沉香行气止痛,茯苓渗湿健脾,生姜和胃散寒。笔者运用暖肝煎化裁治疗输尿管结石、室女痛经,疗效满意。 展开更多
关键词 输尿管结石 室女痛经 暖肝煎 中医药治疗
下载PDF
Applying deep neural networks to the detection and space parameter estimation of compact binary coalescence with a network of gravitational wave detectors 被引量:1
19
作者 XiLong Fan Jin Li +2 位作者 Xin Li YuanHong Zhong JunWei Cao 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2019年第6期122-129,共8页
In this paper, we study an application of deep learning to the advanced laser interferometer gravitational wave observatory(LIGO)and advanced Virgo coincident detection of gravitational waves(GWs) from compact binary ... In this paper, we study an application of deep learning to the advanced laser interferometer gravitational wave observatory(LIGO)and advanced Virgo coincident detection of gravitational waves(GWs) from compact binary star mergers. This deep learning method is an extension of the Deep Filtering method used by George and Huerta(2017) for multi-inputs of network detectors.Simulated coincident time series data sets in advanced LIGO and advanced Virgo detectors are analyzed for estimating source luminosity distance and sky location. As a classifier, our deep neural network(DNN) can effectively recognize the presence of GW signals when the optimal signal-to-noise ratio(SNR) of network detectors ≥ 9. As a predictor, it can also effectively estimate the corresponding source space parameters, including the luminosity distance D, right ascension α, and declination δ of the compact binary star mergers. When the SNR of the network detectors is greater than 8, their relative errors are all less than 23%.Our results demonstrate that Deep Filtering can process coincident GW time series inputs and perform effective classification and multiple space parameter estimation. Furthermore, we compare the results obtained from one, two, and three network detectors;these results reveal that a larger number of network detectors results in a better source location. 展开更多
关键词 deep neural networks ADVANCED LIGO and ADVANCED virgo coincident DETECTION of GRAVITATIONAL waves multiple SPACE parameter estimation
原文传递
内蒙古苏里格南区块天然气开发生态影响预测研究
20
作者 秦卫华 王会 +2 位作者 刘坤 李道进 田红 《干旱区资源与环境》 CSSCI CSCD 北大核心 2010年第6期16-20,共5页
苏里格南区块气田位于鄂尔多斯高原东南部的毛乌素沙地腹地,自然生态环境十分脆弱,具有极其重要的生态保护价值。通过工程分析,天然气开发必然会对区内生态环境造成巨大的影响,主要体现在对自然植被的破坏和对野生动物的干扰两个方面。... 苏里格南区块气田位于鄂尔多斯高原东南部的毛乌素沙地腹地,自然生态环境十分脆弱,具有极其重要的生态保护价值。通过工程分析,天然气开发必然会对区内生态环境造成巨大的影响,主要体现在对自然植被的破坏和对野生动物的干扰两个方面。为科学预测其生态影响,先后对项目区进行了自然植被和鸟类实地专项调查,查明了自然植被的种类、类型和分布,并首次在项目区发现了国家Ⅱ级重点保护鸟类蓑羽鹤(Anthropoides virgo)的繁殖种群及其主要分布区域,结合工程资料,预测了生态影响,并提出了具体的减缓影响的生态保护措施和建议。 展开更多
关键词 苏里格南区块 天然气 植被 蓑羽鹤 生态影响
原文传递
上一页 1 2 下一页 到第
使用帮助 返回顶部