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考虑“筒中筒”耦合作用的深水隔水管柱与钻柱碰摩运动规律
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作者 狄勤丰 骆大坤 +2 位作者 秦垦 王文昌 陈锋 《石油钻采工艺》 CAS 北大核心 2024年第1期25-32,共8页
深水钻井时,旋转钻柱与海洋环境力作用下发生振动的隔水管柱易发生接触,造成钻柱与隔水管柱的碰撞或者摩擦。为了解隔水管柱与钻柱间的运动状态,减轻两者间碰摩,保证作业安全性,提出了一种模拟深水隔水管柱-钻柱组成的“筒中筒”耦合系... 深水钻井时,旋转钻柱与海洋环境力作用下发生振动的隔水管柱易发生接触,造成钻柱与隔水管柱的碰撞或者摩擦。为了解隔水管柱与钻柱间的运动状态,减轻两者间碰摩,保证作业安全性,提出了一种模拟深水隔水管柱-钻柱组成的“筒中筒”耦合系统模型,通过分析二者间的位移与接触力,实现海洋深水钻井作业时隔水管柱与钻柱的耦合动力学模拟的建立。模拟结果表明,考虑隔水管柱与钻柱接触的情况下,海流作用和涡激作用对钻柱的动力学特征具有较大影响;海流速度增加,隔水管柱弯曲程度变大,隔水管柱的振动特征会限制钻柱运动;井口转速增加对钻柱的涡动特征影响小,但会增大钻柱与隔水管柱内壁的接触力,增大钻柱与隔水管柱的失效风险。该理论为海洋深水钻井摩阻分析提供了新的借鉴。 展开更多
关键词 深水钻井 钻柱动力学 “筒中筒”耦合结构 隔水管柱-钻柱耦合振动 接触碰撞
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Synthesis of ZrO2—Al2O3 Ultrafines Composites and Their Sintering Behavior
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作者 CHENZhiqiang qinfeng 《China's Refractories》 CAS 1997年第1期34-39,共6页
Four kinds of ultrafies were manufac-tured by different methods,Sintering behavior,mechanical properties,thermal shock resis-tance and microstructure were studied,ZrO2 grains and Al2O3 grains can inhibit each other... Four kinds of ultrafies were manufac-tured by different methods,Sintering behavior,mechanical properties,thermal shock resis-tance and microstructure were studied,ZrO2 grains and Al2O3 grains can inhibit each other's growth during sintering process,ZrO2-Al2O3 comosites have higher sintering temperatures than single Y-ZrO2 or Al2O3 materials,Proper ZrO2 addition can reinforce and densify Al2O3 ultrafines material as well as improve thermal shock resistance,20wt% Al2O3 doped to 3Y-ZrO3 material is beneficial to stability of ZrO2 materials,the bend strength can reach 817.8 MPa. 展开更多
关键词 氧化锆 三氧化二铝 ZRO2 AL2O3 超细合成物 烧结性
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A study of specific interaction of the transcription factor and the DNA element by atomic force microscopy 被引量:4
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作者 qinfeng JIANGYaxin +4 位作者 MAXinyong CHENFeng FANGXiaohong BAIChunli LIYiqin 《Chinese Science Bulletin》 SCIE EI CAS 2004年第13期1376-1380,共5页
Atomic force microscopy (AFM) was employed to quantitatively detect the interaction between a transcription factor, ZmDREBIA, and its target DNA sequence (DRE).The specificity of the interaction was revealed by compar... Atomic force microscopy (AFM) was employed to quantitatively detect the interaction between a transcription factor, ZmDREBIA, and its target DNA sequence (DRE).The specificity of the interaction was revealed by comparing the binding probability of ZmDREBIA to DRE element with core sequence ACCGAC and to the ERE element with core sequence AGCCGCC. Moreover, the single-molecular unbinding force between ZmDREBIA and DRE element was determined using Poisson statistical method to be 99±9 pN.The results indicated that AFM could serve as a sensitive and reliable technique to probe the interaction properties of the transcription factor and DNA element at single-molecular level, thus indicating that AFM is advantageous over the traditional methods, such as the electrophoretic mobility shift assay, regarding to the functional analysis of transcription factors. 展开更多
关键词 转录因子 DNA 原子增强显微镜方法 AFM ZmDREBIA 转基因作物 玉米
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