关于水稻雄性不育“质核互作诱导”的一点浅见     

张明初 《气象与减灾研究》1998,(1)

通过对水稻雄性不育的遗传分析,提出了雄性不育“质、核互作诱导’的遗传假说。并据此还提出采用“质、核双杂交”的方法来克服亚种间杂交不亲和性的设想,供探讨。  相似文献   

大别山超高压变质带p-T-t轨迹数值模拟   总被引：3，自引：0，他引：3  

金维浚  石耀霖 《地学前缘》1998,(Z1)

模拟设计了拆沉底辟模型、叠瓦俯冲纯剪切伸展模型二组共９种模型。拆沉底辟模型,第一阶段ｐ Ｔ ｔ轨迹在地幔热影响下都为降压增温过程,第二阶段ｐ Ｔ ｔ轨迹明显不同,快速折返速率下为近等温降压,从深部抬升到岩石圈底为显著的降压升温、近等温降压过程,从岩石圈底部经过地壳出露地表为降温降压过程。慢速抬升速率下,为降温降压。模拟比较了底辟上升俯冲板片形态不变与板片形态改变模型,陆壳与陆壳俯冲碰撞和陆壳与洋壳俯冲碰撞,在岩石圈深度范围内ｐ Ｔ ｔ轨迹形态基本相似,首先是等温降压然后降温降压。叠瓦俯冲纯剪切伸展模型,快速伸展速率下ｐ Ｔ ｔ轨迹表现出３个不同的阶段：从降温降压到近等温降压,然后再降温降压。慢速伸展速率下ｐ Ｔ ｔ轨迹为开阔弧形形态,首先为降压增温,然后为降压降温。  相似文献   

四川石棉草科穹状变形变质体研究     

郭建强  喻安光  游再平  杨军 《四川地质学报》1998,(4)

位于扬子陆块西缘的石棉草科穹状变形变质体,经历了三次变形变质时期：早期为收缩滑脱变形的区域动力变质、中期热隆伸展动热变质和后期岩浆热接触变质。对主期变质进行了划分,利用变质反应、矿物地质温压计及相关的同位素年龄资料,建立了草科穹状变形变质体演化的ＰＴｔＤ轨迹。  相似文献   

哈密地区东部一次低涡天气分析     

阿依夏木 《沙漠与绿洲气象(新疆气象)》2004,27(6):9-10

通过对2004年6月4日哈密地区东部大降水天气过程的分析表明，大降水是在北支低槽不断得到北方冷空气的补充，在哈密地区东部加深并切成低涡，低涡中心不连续西退，再加上特殊地形的共同作用的结果。并指出T’。，物理量预报产品对哈密地区大降水预报有很好的参考价值。  相似文献   

水体同位素组成及氘过量参数在地热勘探中的示踪作用--以四川绵竹三箭水温泉开发为例   总被引：2，自引：0，他引：2  

杨波  尹观 《矿物岩石地球化学通报》2004,23(2):129-133

本文研究了四川绵竹三箭水及其邻区水体的同位素组成特征,以氚过量参数(d=δD-8δ^18O)在地热勘探中的示踪作用，再通过对研究区地下水氚过量参数和水笨氰含量(T)的相关性分析，综合运用于查明区内温泉地下水的成因，包括地下热储层内地下水的来源、补给源区、运移途径等等；确定水体均来源于大气降水，山前盆地深部地下水的补给源区在西、西北部高山区,径流方向由西北向东南，径流途径和在地下滞留时间都很长，并由此圈定了几个地热勘查的重点靶区。  相似文献   

Variation in Metamorphic Style along the Northern Margin of the Damara Orogen, Namibia   总被引：2，自引：0，他引：2  

GOSCOMBE  BEN; GRAY  DAVID; HAND  MARTIN 《Journal of Petrology》2004,45(6):1261-1295

The northern margin of the Inland Branch of the Pan-AfricanDamara Orogen in Namibia shows dramatic along-strike variationin metamorphic character during convergence between the Congoand Kalahari Cratons (M₃ metamorphic cycle). Low-P contact metamorphismwith anticlockwise P–T paths dominates in the westerndomains (Ugab Zone and western Northern Zone), and high-P Barrovianmetamorphism with a clockwise P–T path is documented fromthe easternmost domain (eastern Northern Zone). The sequenceof M₃ mineral growth in contact aureoles shows early growthof cordierite porphyroblasts that were pseudomorphed to biotite–chlorite–muscoviteat the same time as an andalusite–biotite–muscovitetransposed foliation was developed in the matrix. The peak-Tmetamorphic assemblages and fabrics were overprinted by crenulationsand retrograde chlorite–muscovite. The KFMASH P–Tpseudosection for metapelites in the Ugab Zone and western NorthernZone contact aureoles indicates tight anticlockwise P–Tloops through peak metamorphic conditions of 540–570°Cand 2·5–3·2 kbar. These semi-quantitativeP–T loops are consistent with average P–T calculationsusing THERMOCALC, which give a pooled mean of 556 ± 26°Cand 3·2 ± 0·6 kbar, indicating a high averagethermal gradient of 50°C/km. In contrast, the eastern NorthernZone experienced deep burial, high-P/moderate-T Barrovian M₃metamorphism with an average thermal gradient of 21°C/kmand peak metamorphic conditions of c. 635°C and 8·7kbar. The calculated P–T pseudosection and garnet compositionalisopleths in KFMASH, appropriate for the metapelite sample fromthis region, document a clockwise P–T path. Early plagioclase–kyanite–biotiteparageneses evolved by plagioclase consumption and the growthof garnet to increasing X_Fe, X_Mg and X_Ca and decreasing X_Mncompositions, indicating steep burial with heating. The developedkyanite–garnet–biotite peak metamorphic parageneseswere followed by the resorption of garnet and formation of plagioclasemoats, indicating decompression, which was followed by retrogressivecooling and chlorite–muscovite growth. The clockwise P–Tloop is consistent with the foreland vergent fold–thrustbelt geometry in this part of the northern margin. Earlier formed(580–570 Ma) pervasive matrix foliations (M₂) were overprintedby contact metamorphic parageneses (M₃) in the aureoles of 530± 3 Ma granites in the Ugab Zone and 553–514 Magranites in the western Northern Zone. Available geochronologicaldata suggest that convergence between the Congo and KalahariCratons was essentially coeval in all parts of the northernmargin, with similar ages of 535–530 Ma for the main phaseof deformation in the eastern Northern Zone and Northern Platformand 538–505 Ma high-grade metamorphism of the CentralZone immediately to the south. Consequently, NNE–SSW-directedconvergent deformation and associated M₃ metamorphism of contrastingstyles are interpreted to be broadly contemporaneous along thelength of the northern margin of the Inland Branch. In the westheat transfer was dominated by conduction and externally drivenby granites, whereas in the east heat transfer was dominatedby advection and internally driven radiogenic heat production.The ultimate cause was along-orogen variation in crustal architecture,including thickness of the passive margin lithosphere and thicknessof the overlying sedimentary succession. KEY WORDS: Pan-African Orogeny; P–T paths; pseudosections; low-P metamorphism; contact metamorphism; Barrovian metamorphism  相似文献   

一次大降水天气过程的特征分析     

屈梅 《沙漠与绿洲气象(新疆气象)》2002,25(4):6-8

对巴州地区一次大范围的强降水、冰雹天气作了分析，重点从环流形势、不稳定条件、卫星云图等方面阐明了形成大范围降水的有利条件。指出卫星云图可以提供对中小尺度天气系统的识别和监测，直观反映出大降水，尤其是冰雹的落区，最后，通过对比分析，证明T106产品在预报中的准确性较高，有一定的参考价值。  相似文献   

中坝须二气藏工艺排水规模的论证     

匡建超  王玉兰  何春蕾  詹廷选  杨正文 《矿物岩石》2002,22(3):72-75

应用双重介质气水二维二相模型，借助排水采气的单井处理技术，针对中坝须二气藏目，前排水采气中存在的问题，成功地对该气藏排水规模进行了论证，推荐了科学合理的排水规模（方案），对该气藏的排水采气具有指导意义，可为气藏排水采气的方案论证借鉴。  相似文献   

Reconstruction of summer temperature (June-August) at Mt. Helan, China, from tree-ring stable carbon isotope values since AD 1890   总被引：3，自引：0，他引：3  

刘禹  马利民  蔡秋芳  安芷生  刘卫国  高玲瑜 《中国科学D辑(英文版)》2002,45(12)

From stable carbon isotope analysis of tree-rings of Chinese pine (Pinus tabulaeformis) from Mt. Helan, China, we found that high-δ13C values were related to high mean temperatures from June to August (T68), and low-δ 13C values corresponded to low T68. From these data, a transfer function has been used to reconstruct summer temperatures (T68) for the Mt. Helan region. The explained variance of reconstruction is 34.9% (F=15.01, p<0.001). The time period containing the highest summer temperatures in northern China (late 1920-1930s) was confirmed by our reconstruction. The data indicate that there is a tele-connection between summer temperatures in Mt. Helan area and sea-surface-temperatures in the tropical Pacific. The extreme low temperature periods around the years of 1920 and 1947 for Mt. Helan region correspond well to the cold climate in the tropical Pacific. Along with other analyses, this suggests that climate variations in the Mt. Helan region are driven not only by local events, but also by the global climate. Significant periodicities appearing in the reconstruction are 2.56 and 2.63 years.  相似文献   

核磁共振测井技术在桩海地区及其它油田中的应用     

史秋贤  冯斌 《地球物理学进展》2002,17(4):690-696

阐明核磁共振测井（NMR）在储层评价中的作用。利用NMR测井资料对桩海地区长堤油田的储层特性及产能、复杂岩性储层的孔隙度作出评价，并在电阻率测井资料显示不好的复杂储层条件下进行油气水层识别，以及指导完井和钻井方案的实施等。不阐明了核磁共振测井技术具有常规测井技术所不具备的特点，特别是定量的评价孔隙流体流动特性、准确划分产层、直接识别油气水等优点，从而有利于解复杂的地质问题。  相似文献