吉林-黑龙江高压变质带的初步厘定:证据和意义   总被引：14，自引：11，他引：3  

周建波  韩杰  Simon A WILDE  郭晓丹  曾维顺  曹嘉麟 《岩石学报》2013,29(2):386-398

本文定义的吉林-黑龙江高压变质带是指我国东北地区佳木斯-兴凯地块西缘和南缘共同发育的呈弧形展布的高压变质带,具体包括佳木斯-兴凯地块西缘增生杂岩带(黑龙江蓝片岩带和张广才-小兴安岭增生杂岩带)和佳木斯-兴凯地块南缘的长春-延吉增生杂岩带.其中佳木斯-兴凯地块西缘增生杂岩带形成于晚三叠-早侏罗世(180 ～ 210Ma),为佳木斯-兴凯地块向西冲增生而形成的高压变质带;而长春-延吉增生杂岩带由一系列特征性俯冲-增生杂岩组成,包括石头口门-烟筒山红帘石片岩带、呼兰群变质杂岩、色洛河群变质杂岩、青龙村群变质杂岩和开山屯变质杂岩等,形成时代为187～230Ma,峰期为220～230Ma.长春-延吉增生杂岩带曾被认为是西拉木伦河断裂带的东延部分,但是区域构造分析表明,它们形成的动力学背景与佳木斯-兴凯地块西缘增生杂岩带相同,均为太平洋板块三叠纪-早侏罗世的西向俯冲导致佳木斯-兴凯地块自东向西的“剪刀式”闭合过程.我们将佳木斯-兴凯地块西缘和南缘发育的三叠纪-早侏罗世增生杂岩带作为统一的构造单元来考虑,结合该区发育有典型的高压变质带,因此命名为“吉林-黑龙江高压变质带,简称吉黑高压带”.吉黑高压带形成于太平洋板块三叠纪-早侏罗世的西向俯冲导致佳木斯-兴凯地块自东向西的“剪刀式”闭合的过程,同时该带记录了古亚洲构造域的结束和太平洋俯冲开始的关键时期,为两大构造域叠加与转换的关键性地质证据.  相似文献   

光管式与螺纹管式泥浆制冷换热器的对比分析研究     

刘卫卫  孙友宏  郭威  李冰  李卓明 《探矿工程》2013,40(2):7-11

介绍了泥浆制冷系统及同轴套管式换热器的结构与工作原理,采用传热计算和传热数值模拟分析方法,对光管式换热器与螺纹管式换热器从传热系数和换热面积进行对比分析研究。对比分析结果表明,在满足水合物钻探取样的条件下,螺纹管式换热器可增大换热面积,从而使螺纹管式换热器的体积和质量较光管式换热器可减少50%～60%,在相同规格条件下,螺纹管式换热器的换热效率大约是光管式换热器的2～3倍。  相似文献   

The theory and application of the structure light engineering surveying based on a laser theodolite with three freedoms of rotation     

Feng Wenhao  Li Xin 《地球空间信息科学学报》2013,16(1):28-36

The concepts of “confining structure” and structure light are illuminated in this paper. A laser theodolite with three freedoms of rotation, which is aimed at “confining structure”, is developed. Various scanning modes and their mathematical models based on laser theodolite with three freedoms of rotation are discussed. According to the features of a huge object the structure light engineering surveying based on laser theodolite with three freedoms of rotation is determined as the main method in an actual application. The observation of four sound concrete posts and forced centering plates. Subsequently, it is transformed into the huge object coordinate system. The scanning mode with plumb plane is selected as the main mode in the whole work. And other assistant methods, such as close range photogrammetry and the method of using reflection sheet, are applied to the work of “scanning dead angle”. At last, a surveying accuracy estimation of this method is done and a surveying accuracy test is finished. It can be concluded that the structure light engineering surveying based on laser theodolite with three freedoms of rotation is considered to be an effective and applied method, and has many superiority to some other surveying methods in the work of surveying “confining structure”.  相似文献   

地下水位对胡杨(Populus euphratica)和灰胡杨(Populus pruinosa)叶绿素荧光光响应与光合色素含量的影响   总被引：1，自引：0，他引：1  

王海珍  陈加利  韩路  徐雅丽  贾文锁 《中国沙漠》2013,33(4)

在塔里木河上游利用便携式调制叶绿素荧光仪研究了地下水位对胡杨(Populus pruinosa)和灰胡杨(Populus pruinosa)光合色素和叶绿素荧光光响应的影响.结果表明:不同地下水位环境下,2树种表观光合电子传递速率(ETR)、非光化学猝灭系数(NPQ)、PSⅡ激发能压力(1-qP)、天线色素热耗散能量(D)、非光化学反应耗散能量(E)、光合功能相对限制值(PED)和光系统间激发能分配不平衡偏离系数(β/α-1)随光合有效辐射(PAR)增加而升高,PSⅡ实际光化学效率(ΦPSⅡ)、光化学猝灭系数(qP)和光化学反应能量(P)则随PAR增加而降低;相同光强下,地下水位下降导致胡杨和灰胡杨叶片含水量、最大电子传递速率(ETRmx)、光化学反应启动速率(θ)、ETR、ΦPSⅡ、qP、P与叶绿素(Chla、Chlb、Chl(a+b))和类胡萝卜素(Car)含量降低,而使Chla/b、NPQ、D、E、PED、1-qP、β/α-1明显升高;地下水位下降显著影响2树种叶绿素荧光光响应参数,引起光能吸收、传递与分配改变,致使光合效率降低;地下水位下降对灰胡杨光合生理过程的影响程度明显高于胡杨,表明胡杨对荒漠逆境的适应性强于灰胡杨.逆境下胡杨通过维持相对较高的ETR、ETRmax、θ、ΦPSⅡ、qP、P值,并通过增强非辐射性热耗散来调节自身能量代谢,以此来保护光合机构正常运转,这是胡杨长期适应干旱荒漠逆境而形成的一种自我调节机制.  相似文献   

Effects of blue light on gametophyte development of Laminaria japonica （Laminariales, Phaeophyta）     

史翠娟  KATAOKA Hironao  段德麟 《中国海洋湖沼学报》2005,23(3):323-329

1 INTRODUCTION Light acts as an important ambient factor to regulate plant growth. Several critical points in life history for many marine algae are controlled by light. Photobiology of algae has been a discipline of particular interest for a long time (Dring, 1988). Many light effects on algae are photoperi- odic-regulated, such as sporangia formation in red algae Porphyra tenera (Rentschler, 1967) and As- paragopsis armata (Oza, 1976), and erect thalli de- velopment in brown algae Scy…  相似文献   

Analysis of Extra-Solar Planetary Transits Using Tools from Eclipsing Binaries     

Àlvaro Giménez 《Astrophysics and Space Science》2006,304(1-4):21-24

Analytical formulae for the computation of the photometric elements of extra-solar planetary transits are presented. They were initially derived for the study of well-detached eclipsing binaries and are valid for any degree of limb darkening and type of transit as well as for eccentric orbits. The only assumption is that the projections of the star and the planet on the plane of the sky are well represented by circular discs. The procedure to get valid ranges for the involved parameters, as well as to make precise estimations of initial parameters, using the analytical nature of the equations is given together with some discussion on their practical application. Examples are shown for OGLE-TR-113, representative of a light curve obtained with ground-based telescopes, and HD 209458 with a precise light curve obtained with the Hubble Space Telescope.  相似文献   

Physical properties of asteroid dust bands and their sources     

David Nesvorný  David Vokrouhlický  Mark Sykes 《Icarus》2006,181(1):107-144

Disruptive collisions in the main belt can liberate fragments from parent bodies ranging in size from several micrometers to tens of kilometers in diameter. These debris bodies group at initially similar orbital locations. Most asteroid-sized fragments remain at these locations and are presently observed as asteroid families. Small debris particles are quickly removed by Poynting-Robertson drag or comminution but their populations are replenished in the source locations by collisional cascade. Observations from the Infrared Astronomical Satellite (IRAS) showed that particles from particular families have thermal radiation signatures that appear as band pairs of infrared emission at roughly constant latitudes both above and below the Solar System plane. Here we apply a new physical model capable of linking the IRAS dust bands to families with characteristic inclinations. We use our results to constrain the physical properties of IRAS dust bands and their source families. Our results indicate that two prominent IRAS bands at inclinations ≈2.1° and ≈9.3° are byproducts of recent asteroid disruption events. The former is associated with a disruption of a ≈30-km asteroid occurring 5.8 Myr ago; this event gave birth to the Karin family. The latter came from the breakup of a large >100-km-diameter asteroid 8.3 Myr ago that produced the Veritas family. Using an N-body code, we tracked the dynamical evolution of ≈10⁶ particles, 1 μm to 1 cm in diameter, from both families. We then used these results in a Monte Carlo code to determine how small particles from each population undergo collisional evolution. By computing the thermal emission of particles, we were able to compare our results with IRAS observations. Our best-fit model results suggest the Karin and Veritas family particles contribute by 5-9% in 10-60-μm wavelengths to the zodiacal cloud's brightness within 50° latitudes around the ecliptic, and by 9-15% within 10° latitudes. The high brightness of the zodiacal cloud at large latitudes suggests that it is mainly produced by particles with higher inclinations than what would be expected for asteroidal particles produced by sources in the main belt. From these results, we infer that asteroidal dust represents a smaller fraction of the zodiacal cloud than previously thought. We estimate that the total mass accreted by the Earth in Karin and Veritas particles with diameters 20-400 μm is ≈15,000-20,000 tons per year (assuming 2 g cm⁻³ particles density). This is ≈30-50% of the terrestrial accretion rate of cosmic material measured by the Long Duration Exposure Facility. We hypothesize that up to ≈50% of our collected interplanetary dust particles and micrometeorites may be made up of particle species from the Veritas and Karin families. The Karin family IDPs should be about as abundant as Veritas family IDPs though this ratio may change if the contribution of third, near-ecliptic source is significant. Other sources of dust and/or large impact speeds must be invoked to explain the remaining ≈50-70%. The disproportional contribution of Karin/Veritas particles to the zodiacal cloud (only 5-9%) and to the terrestrial accretion rate (30-50%) suggests that the effects of gravitational focusing by the Earth enhance the accretion rate of Karin/Veritas particles relative to those in the background zodiacal cloud. From this result and from the latitudinal brightness of the zodiacal cloud, we infer that the zodiacal cloud emission may be dominated by high-speed cometary particles, while the terrestrial impactor flux contains a major contribution from asteroidal sources. Collisions and Poynting-Robertson drift produce the size-frequency distribution (SFD) of Karin and Veritas particles that becomes increasingly steeper closer to the Sun. At 1 AU, the SFD is relatively shallow for small particle diameters D (differential slope exponent of particles with D?100 μm is ≈2.2-2.5) and steep for D?100 μm. Most of the mass at 1 AU, as well as most of the cross-sectional area, is contributed by particles with D≈100-200 μm. Similar result has been found previously for the SFD of the zodiacal cloud particles at 1 AU. The fact that the SFD of Karin/Veritas particles is similar to that of the zodiacal cloud suggests that similar processes shaped these particle populations. We estimate that there are ≈5×¹⁰²⁴ Karin and ≈10²⁵ Veritas family particles with D>30 μm in the Solar System today. The IRAS observation of the dust bands may be satisfactorily modeled using ‘averaged’ SFDs that are constant with semimajor axis. These SFDs are best described by a broken power-law function with differential power index α≈2.1-2.4 for D?100 μm and by α?3.5 for 100 μm?D?1 cm. The total cross-sectional surface area of Veritas particles is a factor of ≈2 larger than the surface area of the particles producing the inner dust bands. The total volumes in Karin and Veritas family particles with 1 μm<D<1 cm correspond to D=11 km and D=14 km asteroids with equivalent masses ≈1.5×¹⁰¹⁸ g and ≈3.0×¹⁰¹⁸ g, respectively (assuming 2 g cm⁻³ bulk density). If the size-frequency and radial distribution of particles in the zodiacal cloud were similar to those in the asteroid dust bands, we estimate that the zodiacal cloud represents ∼3×¹⁰¹⁹ g of material (in particles with 1 μm<D<1 cm) at ±10° around the ecliptic and perhaps as much as ∼¹⁰²⁰ g in total. The later number corresponds to about a 23-km-radius sphere with 2 g cm⁻³ density.  相似文献   

Modelling artificial night-sky brightness with a polarized multiple scattering radiative transfer computer code     

Dana Xavier Kerola † 《Monthly notices of the Royal Astronomical Society》2006,365(4):1295-1299

As part of an ongoing investigation of radiative effects produced by hazy atmospheres, computational procedures have been developed for use in determining the brightening of the night sky as a result of urban illumination. The downwardly and upwardly directed radiances of multiply scattered light from an offending metropolitan source are computed by a straightforward Gauss–Seidel (G–S) iterative technique applied directly to the integrated form of Chandrasekhar's vectorized radiative transfer equation. Initial benchmark night-sky brightness tests of the present G–S model using fully consistent optical emission and extinction input parameters yield very encouraging results when compared with the double scattering treatment of Garstang, the only full-fledged previously available model.  相似文献   

银河系疏散星团中的蓝离散星(英文)     

新宇 《紫金山天文台台刊》2003,(2)

作为目前研究复杂恒星系统的有力工具 ,星族合成方法是建立在单星演化理论基础之上的 ,因此 ,必然有其不完善性存在 ,尤其当系统中的双星成分不容忽视时。作为演化星族合成方法的基本单元 ,简单恒星星族模型的构成即排除了双星贡献。本文中 ,我们以银河系疏散星团为简单恒星星族模板 ,构造出一系列简单恒星星族积分光谱。从中我们可以看到 :蓝离散星这类理论上主要来源于双星系统的恒星 ,对星团积分光谱的紫外及蓝端有很大影响 ,从而造成简单恒星星族积分光谱能量分布的改变。这种改变势必影响对星团年龄及其它一些物理参量的判定 ,并最终影响星族合成的结果。同时 ,若以 (B -V )色指数进行度量 ,蓝离散星对简单恒星星族积分颜色的影响可达到 30 %。工作中 ,我们选取了 2 6个年龄在1x10 1 0 ～ 6x10 1 0 年之间的疏散星团为样本进行统计研究。  相似文献   

二阶后牛顿光线方程   总被引：1，自引：0，他引：1  

宫衍香  须重明 《天文学报》2003,44(4):382-389

近来相继提出一系列的空间天体测量计划，要求考虑在多参考系中二阶后牛顿部分对光线传播的贡献，也就是说，必须讨论在最近完成的扩展的DSX体系下的二阶后牛顿(2PN)光线方程．DSX体系是在20世纪90年代初建立的，用来讨论对N个任意形状和组成、自转可变形物体的一套完整的一阶后牛顿(1PN)天体力学理论．在此建议采用迭代的方法来推导2PN光线方程．从度规和Christoffel记号出发推导太阳系中的2PN光线方程．当忽略掉更高阶的项时，2PN光线方程将回到在很多教科书中广泛出现的1PN光线方程．利用这套方程就可以计算太阳系的光线传播．  相似文献