从前陆盆地充填地层分析盆山耦合关系   总被引：26，自引：0，他引：26  

汪泽成  周海民等 《地球科学》2001,26(1):33-39

根据前陆盆地充填地层分析盆地和造山带的耦合关系，研究区域包括四川中生代前陆盆地和鄂尔多斯中生代前陆盆地。研究表明，前陆盆地和造山带具有较好的耦合关系。前陆盆地充填沉积物特征是造山带形成演化和盆地沉降的响应。向上变粗的沉积序列以及地层不整合盆地方向的迁移反映了造山带向前陆不断隆升的演化过程，前陆盆地沉积物的岩石学特征反映了双物源供给和造山带的剥蚀。层序地层的体系域构成和地层堆积方式主要受控于前陆盆地沉降速度的变化。  相似文献   

Automatic Solar Flare Tracking Using Image-Processing Techniques   总被引：1，自引：0，他引：1  

Ming Qu  Frank Shih  Ju Jing  Haimin Wang 《Solar physics》2004,222(1):137-149

Measurement of the evolution properties of solar flares through their complete cyclic development is crucial in the studies of Solar Physics. From the analysis of solar H images, we used Support Vector Machines (SVMs) to automatically detect flares and applied image segmentation techniques to compute their properties. We also present a solution for automatically tracking the apparent separation motion of two-ribbon flares and measuring their moving direction and speed in the magnetic fields. From these measurements, with certain assumptions, we inferred the reconnection of the electric field as a measure of the rate of the magnetic reconnection in the corona. The automatic procedure is a valuable tool for real-time monitoring of flare evolution.  相似文献   

沉积盆地物质来源综合研究——以南堡老第三纪亚断陷盆地为例   总被引：3，自引：1，他引：2       下载免费PDF全文

焦养泉  李珍  周海民 《沉积与特提斯地质》1998,18(5):16-20

重矿物分析对于判断沉积盆地的物源方向和物源区的母岩性质是有效的,但具有局限性：①对无重矿物或者仅能提供极少量重矿物的母岩判别力较差;②它不能准确判断物源区沉积物的主要运移通道。因此,进行盆地物源分析还需要重视综合研究,即①通过重矿物的矿物学、重矿物组合研究,判断物源区的母岩类型,推测母岩岩性演化;②通过沉积岩矿物成分与结构研究,判别物源区是否存在重矿物无法辨认的母岩类型和沉积物的搬运距离;③通过沉积体系分析,尤其是砂分散体系的编图,能有效地判断物源区的方位和圈定各物源的具体影响范围;④利用古构造图判别物源区的主要沉积物运移通道及其方位;⑤编制沉积盆地－物源区古环境图,以此来弥补重矿物分析物源所带来的缺陷。  相似文献   

Comparison of Prominences in Hα and He  II 304 Å     

Haimin Wang  Jongchul Chae  Joseph B. Gurman  Therese A. Kucera 《Solar physics》1998,183(1):91-96

In this letter, we bring attention to prominences which show different morphology in H and Heii 304 Å, as observed simultaneously by BBSO and EIT on board SOHO. Those two lines have been thought to represent similar chromospheric structures although they are formed at significantly different temperatures. We give two examples representing two kinds of anomaly: (1) prominences showing strong H emissions in the lower part and strong Heii emissions in the upper part, and (2) erupting prominences showing extensive Heii emission, but nothing in H. Our results indicate that a part or the whole of a prominence may be too hot to emit H radiation, possibly due to heating or thermal instability. Please note that these are not just two isolated cases, many other prominences show the similar differences in H and Heii 304 Å.  相似文献   

Lifetime of Intranetwork Magnetic Elements     

Zhang  Jun  Lin  Ganghua  Wang  Jingxiu  Wang  Haimin  Zirin  Harold 《Solar physics》1998,178(2):245-250

Using a 10-hour time sequence of very deep magnetograms of Big Bear Solar Observatory, we have studied the lifetime of Intranetwork Magnetic Elements for the first time. The analysis reveals the following results:(1) The lifetime of intranetwork elements ranges from 0.2 hr to 7.5 hr with the mean of 2.1 hr. There appears to be a quasi-linear dependence of the lifetime on the total flux of elements. (2) Most intranetwork elements appear as a cluster of mixed polarities from an emergence center somewhere within the network boundary and are destroyed by three mechanisms: merging with intranetwork or network elements of the same polarity, cancellation of opposite polarity elements, or separation and disappearance at the position where they appear. (3) We estimate that the total energy released from the recycling of IN elements isinebreak1.6 × 10²⁸ ergs s^-1, which seems to be comparable to the energy required to heat the corona.  相似文献   

Strong transverse fields in δ-spots     

Harold Zirin  Haimin Wang 《Solar physics》1993,144(1):37-43

Spectroscopic measurements of the strength and direction of transverse magnetic fields in six -spots are presented. The field direction is determined by the relative strength of the - and -components at different polarizer orientations, and is, with one exception, parallel to the neutral line and as strong as the umbral field. Field strengths determined by line splitting are as high as 3980 G.  相似文献   

The roots of coronal structure in the Sun's surface     

Leon Golub  Harold Zirin  Haimin Wang 《Solar physics》1994,153(1-2):179-198

We have compared the structures seen on X-ray images obtained by a flight of the NIXT sounding rocket payload on July 11, 1991 with near-simultaneous photospheric and chromospheric structures and magnetic fields observed at Big Bear. The X-ray images reflect emission of both Mgx and Fexvi, formed at 1 × 10⁶ K and 3 × 10⁶ K, respectively. The brightest H sources correspond to a dying sub-flare and other active region components, all of which reveal coronal enhancements situated spatially well above the H emission. The largest set of X-ray arches connected plages of opposite polarity in a large bipolar active region. The arches appear to lie in a small range of angle in the meridian plane connecting their footpoints. Sunspots are dark on the surface and in the corona. For the first time we see an emerging flux region in X-rays and find the emission extends twice as high as the H arches. Many features which we believe to correspond to X-ray bright points (XBPs) were observed. Whether by resolution or spectral band, the number detected greatly exceeds that from previous work. All of the brighter XBPs correspond to bipolar H features, while unipolar H bright points are the base of more diffuse comet-like coronal arches, generally vertical. These diverge from individual features by less than 30°, and give a good measure of what the canopies must do. The H data shows that all the H features were present the entire day, so they are not clearly disappearing or reappearing. We find a new class of XBPs which we call satellite points, elements of opposite polarity linked to nearby umbrae by invisible field lines. The satellite points change rapidly in X-ray brightness during the flight. An M1.9 flare occurred four hours after the flight; examination of the pre-flare structures reveals nothing unusual.  相似文献   

西昆仑库地伟晶辉长岩和玄武岩锆石SHRIMP年龄：库地蛇绿岩的解体   总被引：13，自引：0，他引：13  

张传林  于海锋  沈家林  董永观  叶海敏  郭坤一 《地质论评》2004,50(6):639-643

西昆仑“库地蛇绿岩“是中国西部地区研究程度较高的蛇绿岩之一。对这条蛇绿岩带的时代、构造背景至今存在很大分歧。笔者等在库地超镁铁岩体中 ,获得侵入于橄榄岩中的伟晶辉长岩锆石 SHRIMP年龄为5 2 5± 2 .9Ma,在库地一些克沟获得块状玄武岩锆石 SHRIMP年龄为 4 2 8± 19Ma,这表明库地超镁铁岩和库地一些克沟玄武岩不属于同一时代 ,因此它们可能形成的构造背景也存在差异 ,库地蛇绿岩应解体。本文提供的年代资料为研究这一地区的早古生代构造演化提供了新的资料  相似文献   

Polar fields during the rising phase of cycle 22     

Frances Tang  Haimin Wang 《Solar physics》1991,132(2):247-256

High-resolution magnetograph observations of the polar magnetic fields have been obtained at intervals of time since the end of 1986 at Big Bear Solar Observatory. The Big Bear data differ from the low-resolution, full-disk magnetograph observations in that the 2 arc sec resolution makes it possible to resolve concentrated field upward of 100 G. The purpose of this ongoing observation is to examine the evolution of polar fields during the expected polarity reversal as cycle 22 passes its maximum phase, and secondly, to study the polar magnetic field: its true field strength, distribution, and how it compares to other parts of the quiet Sun.We find that the >70° net polar flux of both poles has not reversed as of the end of 1989. However, in the lower latitudes of both poles, 50° to 70°, there are signs reminiscent of those preceding the reversals in cycles 19 and 20. These include: decreasing field intensity in the old polarity fluctuations in net flux between the old and new polarities.We find that the net average longitudinal polar fields (above 50°) are 1–2 G, in agreement with results found in cycles 19 and 20. For individual elements, however, the strongest observed field strength poleward of 70° is over 100 G.We compare the polar fields with the equatorial limb as a function of latitute and longitude, respectively, and find the polar fields are comparable to (or stronger than) the quiet equatorial limb. When the observed mean flux density of the polar field as a function of latitude is corrected for limb-darkening and projection effects (assuming the field is radial), the result is nearly constant. These results suggest that despite the high latitudes, the polar fields have field strength and distribution similar to other parts of the quiet Sun.  相似文献   

High-Spatial-Resolution Imaging Combining High-Order Adaptive Optics,Frame Selection,and Speckle Masking Reconstruction     

Carsten?DenkerEmail author  Dulce?Mascarinas  Yan?Xu  Wenda?Cao  Guo?Yang  Haimin?Wang  Philip?R.?Goode  Thomas?Rimmele 《Solar physics》2005,227(2):217-230

We present, for the first time, high-spatial-resolution observations combining high-order adaptive optics (AO), frame selection, and post-facto image correction via speckle masking. The data analysis is based on observations of solar active region NOAA 10486 taken with the Dunn Solar Telescope (DST) at the Sacramento Peak Observatory (SPO) of the National Solar Observatory (NSO) on 29 October 2003. The high Strehl ratio encountered in AO corrected short-exposure images provides highly improved signal-to-noise ratios leading to a superior recovery of the object’s Fourier phases. This allows reliable detection of small-scale solar features near the diffraction limit of the telescope. Speckle masking imaging provides access to high-order wavefront aberrations, which predominantly originate at high atmospheric layers and are only partially corrected by the AO system. In addition, the observations provided qualitative measures of the image correction away from the lock point of the AO system. We further present a brief inspection of the underlying imaging theory discussing the limitations and prospects of this multi-faceted image reconstruction approach in terms of the recovery of spatial information, photometric accuracy, and spectroscopic applications.The editors apologize to the authors: due to a misunderstanding during the editorial process, the publication of this paper has been delayed.  相似文献