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1.
本文数值模拟研究了中性束注入等离子体产生的快离子空间分布,讨论了快离子空间分布随中性束在等离子体中平均自由程变化情况.采用HL_2A装置参数模拟了线束和扩散束两种情况下快离子的空间分布,结果表明束粒子在等离子体中的平均自由程对束的沉积剖面影响较大,当平均自由程与小半径相当时快离子密度分布在在磁轴处有一个较大的峰值.  相似文献   

2.
分析了HT-7托卡马克壁处理前后欧姆放电时的自举电流占总等离子体电流比例的变化情况.壁处理以后,等离子体的密度分布变宽,等离子体压力梯度在边界较大,边界的电子温度比壁处理前高,从而碰撞频率降低,使得自举电流成份比例从壁处理前的小于5%增大到百分之十几.这一变化解释了壁处理后稳态放电时,等离子体电流可以轻松放大且等离子体电流分布变宽的现象.  相似文献   

3.
利用静电探针对弱磁场中直流辉光放电等离子体参数进行了诊断,测量了等离子体的密度和温度.结果表明,离子密度随放电电流的增加而增加,随气压的升高而升高;电子温度随放电电流的增加而增加,随气压的升高而降低;在磁场中,离子密度随磁场的增强而增大,电子温度随磁场的增加而减小.实验结果与理论计算结果基本趋势相一致.  相似文献   

4.
EAST托卡马克拉长位形演化的数值模拟   总被引:1,自引:1,他引:0  
文章利用TSC对先进实验超导托卡马克(EAST)拉长偏滤器位形的放电进行了数值模拟,放电全过程中等离子体电流、等离子体大半径、小半径、拉长比随时间演化的模拟结果与实验结果及与EFIT反演结果吻合很好,为相关实验和开展更深入的EAST放电模拟研究提供了理论依据。  相似文献   

5.
利用硬X射线诊断系统,对比分析了提高等离子体密度对欧姆放电和低杂波电流驱动放电下逃逸电子行为的影响.实验结果表明:在欧姆放电平顶阶段提高等离子体密度能有效抑制强逃逸分布,然而在低杂波关断时提高等离子体密度并没有抑制电子逃逸,反而出现逃逸电子雪崩增长.根据不同逃逸产生机制对该现象进行了对比分析.  相似文献   

6.
磁控溅射驱动方式是影响其等离子体特征的重要因素之一,而等离子体行为最终影响所沉积薄膜结构和性能。磁控溅射过程中基体上产生的浮动电势与等离子体中电子能量分布有关,基体饱和电流则与等离子体的离子密度有关,可综合反映辉光放电系统等离子体状态。本实验分别采用射频、直流和脉冲直流电源溅射Mo粉末靶,改变靶基距,测量基体浮动电势及饱和电流,探讨溅射驱动方式对等离子体行为的影响。研究表明:靶功率增加,靶电压、电流均随靶功率增大,基体浮动电势基本保持不变,基体饱和电流增加,但电压增加率极小,而电流增加率较大。基体浮动电势绝对值随靶基距的增加而降低,即电子的能量分布随靶基距增加而降低。射频溅射产生的浮动电势明显小于直流和脉冲直流溅射的。直流溅射等离子体能量最高,射频溅射等离子体密度最大。  相似文献   

7.
平面电磁波在等离子体中的吸收衰减   总被引:7,自引:0,他引:7  
研究等离子体在隐身技术中的应用.采用垂直入射线极化平面电磁波斜入射到具有金属衬底的等离子体层的模型,利用W.K.B解,推导出电磁波能量衰减与电磁波频率和等离子体密度的关系式.在此基础上,对不同入射角的电磁波在等离子体密度为均匀分布、线性分布和指数分布情况下传播的能量衰减进行了数值计算.结果表明,电磁波衰减随等离子体密度以及电磁波入射角增加而增加;在3种分布情况下电磁波能量衰减规律是相似的.  相似文献   

8.
等离子体平衡是托卡马克等离子体放电和控制的基础,文章利用Corsica程序,结合实验给出EAST放电过程中等离子体平衡位形的建立和等离子体电流、密度及温度剖面分布信息;同时在平衡位形建立的基础上开展了放电模拟研究,脉冲过程中等离子体电流稳定演化、等离子体大半径和小半径等重要参数的模拟结果与实验吻合较好.  相似文献   

9.
水下等离子体放电时,两电极间会形成高导电性的放电通道.放电通道的电阻随时间变化,从放电初期的几欧姆到中期的几毫欧姆,在放电后期又会迅速升高.水下等离子体放电有多种形式的能量产生,本文在较全面考虑主要能量形式的基础上,对气泡内能、气泡脉动能、冲击波能等不同能量进行系统的分析计算,结合实验测定的放电电流和冲击波压力,提出利用能量守恒定律对水下等离子体放电通道的电阻进行计算的方法,并与其它计算放电通道电阻的方法进行了比较,对比得出该方法的简便性和可靠性,并简要给出了能量转换控制的建议.  相似文献   

10.
在固定脉冲频率及占空比的情况下,研究脉冲电压对大气压脉冲放电等离子体射流长度的影响。分析脉冲放电的电流电压波形、等离子体射流的光发射强度的时空演化过程以及等离子体子弹速度的变化。结果表明:等离子体子弹随脉冲电压的增大由单子弹变为双子弹再变为单子弹;射流长度相应地先增长然后趋于稳定,射流长度由增长转变为稳定的转变电压正好处于形成双子弹的脉冲电压附近。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

16.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

17.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

18.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

19.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

20.
赵英华 《科技信息》2008,(12):219-220
0.Preface China has long been boasting of its colorful and immense culture which comprises of Taoism,Confucianism and Buddhism.The interwoven influence among the religions on Chinese way of thinking,on the nation's behavior in their social life throughout the long history is beyond list.  相似文献   

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