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1.
介质阻挡放电系统中首次在具有D_(2h)对称性放电气隙中获得斑图.该放电气隙是由4个条型结构组成,每个条型都是由圆形和矩形交替排列属于D_(2h)点群,在圆形与矩形的放电气隙双重调制下获得斑图的演化是从D_(4h)向D_(2h)的转变,并实现一种可调控的等离子体光子晶体.本实验对圆形区域内的放电行为进行研究.采用高速照相机对其时空结构进行测量,结果表明,斑图Ⅱ是由中心点、边框点、晕三套子结构相互嵌套而成,晕的形状呈环状.用高速录像机对环状的晕进行拍摄,可以观察到晕是由随机放电丝组成.采用光谱仪分别对不同子结构的等离子体参量进行测量.最后用壁电荷理论解释分析了斑图形成的机制以及环状晕形成的原因.  相似文献   

2.
本实验首次在双水电极介质阻挡放电装置中获得暗环白眼超四边形斑图.该斑图的每个四边形晶胞内都包含一个由黑色圆环围绕的中心亮点.这种黑色圆环围绕中心亮点的结构类似于白眼晶胞,称为暗环白眼.利用高速照相机研究暗环白眼超四边形斑图的时空结构.结果发现,暗环白眼超四边形斑图由4套不同的子结构相互嵌套而成,在每半个外加电压周期内,子结构的放电顺序依次为:中心亮点-亮点晕-顶点四边形-顶点连线.其中,暗环白眼是由中心亮点和周围的环形不放电区域组成的.利用壁电荷理论解释了暗环白眼超四边形斑图的形成机制和暗环的形成原因.  相似文献   

3.
在介质阻挡放电系统中首次发现了带线六边形斑图.利用高速照相机和光电倍增管对斑图的时空结构和时间相关性进行测量,发现该斑图是由带线六边形内的中心点、带线六边形上的点及线和带线六边形内晕3套子结构组成,分别将其记作C(center),V(vertex)+L(line),H(halo),放电全部发生在电压上升沿.利用2个光电倍增管同时对V、L处进行测量,发现二者都在第2个电流脉冲放电且放电顺序随机.利用高速录像机拍摄曝光时间为50 μs放电照片,发现L是由随机放电丝组成.利用壁电荷理论解释带线六边形斑图的时空结构及形成机制.  相似文献   

4.
在介质阻挡放电系统中,首次观察到一个由六边形点阵和四边形点阵嵌套而成的D_(2h)超点阵斑图.采用高速照相机(ICCD)研究了D_(2h)超点阵斑图的时空动力学结构,分析可知:D_(2h)超点阵斑图是由六边形子点阵、晕和四边形子点阵相互嵌套而成,且在每个外加电压半周期内子点阵的放电顺序依次为:六边形子点阵、晕、四边形子点阵.通过分析演化过程中出现的一系列斑图,发现对称性的演化顺序为:D_(4h)-D_(4h)和D_(6h)的混合态-D_(2h)-D_(2h),演化过程中斑图的对称性逐渐降低.通过分析子结构的对称性发现六边形子点阵、晕和四边形子点阵均属于D_(2h)点群.利用发射光谱法采集了氮分子(N_2)第二正带系(C~3∏_u→B~3∏_g)的发射谱线和氩原子696.57 nm (2P_2→1S_5)处的发射谱线,并计算得到了D_(2h)超点阵斑图中不同子结构的分子振动温度和电子密度.结果显示3套不同子结构的分子振动温度和电子密度相近,由此表明3套不同子结构的等离子体状态基本相同.最后,用壁电荷理论对斑图的形成进行分析.  相似文献   

5.
在高氩气含量的混合气体放电中,首次观察到大小点不完全插空的新型超四边形斑图.采用高速相机(ICCD)和光电倍增管(PMT),对此斑图的时空动力学进行了研究.结果表明,斑图由三套不同的子结构相互嵌套构成,每半个电压周期内子结构的放电顺序为:小点-大点晕-大点中心点.并且在每半个电压周期的下降沿,中心点的放电对应着两个明显的电流脉冲,放电时刻具有选择性.经分析可知:由于中心点在下降沿放电的时刻具有选择性,中和掉大点晕的壁电荷量不同,导致不同的中心点周围电场强度不均,因此每个小点不在4个大点结构的中心"插空放电".  相似文献   

6.
利用双水电极介质阻挡放电装置,在高pd值流光放电模式下,分别获得了四边形斑图和超四边形斑图.观察到了2种斑图之间的相互转化和时空对称性破缺.此外,对超四边形斑图中的大点进行了时空分辨测量.结果表明:在每半个电压周期内,大点的中心和边缘均是放电2次,具有相同的时空行为,由此证明了第2次放电应为壁电荷引起,而不是由于存在第2个放电丝.  相似文献   

7.
采用特殊的双水电极的介质阻挡放电装置,得到了特殊的超六边形斑图,其有2个独立的波模qs,Khc,遵循三波共振原理qs1+qs2=Kch.并对其时空动力学进行了研究,此种斑图由2套次结构交替放电形成,所有小点同时放电,大点同时放电.  相似文献   

8.
在介质阻挡放电中首次发现了由沿面放电相互排斥而形成的超四边形斑图,该斑图是由亮点、暗点、亮线组成的.用普通相机对该斑图进行短曝光拍摄,发现暗点是由四个小点组成的.用高速录像机对斑图进行曝光时间为20μs的拍摄,发现暗点是由沿面放电的相互排斥形成的,亮点是体放电.用逐渐增加高速录相机曝光时间的方法对斑图进行拍摄,结果发现,亮线是沿面放电在长时间下叠加而成的.对斑图的亮暗点的光强作了对比,发现亮点和暗点的光强之比约为10.用光电倍增管对斑图进行光信号的测量发现亮点在每半周期内进行多次放电,其中仅有一次在电压的下降沿,也反映出暗点和亮线的放电模式与亮点不一样.最后通过光谱的测量表明:亮点与亮线和暗点有不同的等离子体参数,证实亮点和暗点是不同的放电模式.最后采用壁电荷理论对斑图的形成进行了解释.  相似文献   

9.
超点阵斑图形成前放电丝时空特征   总被引:1,自引:1,他引:0  
为了更清楚地了解超点阵版图形成的规律,实验研究了介质阻挡放电中超点阵形成前放电丝的时空特征.结果发现,如果单个放电丝边界呈锯齿状,放电丝没有固定的运动方向,并且单个放电丝的放电时间间隔没有明显的长短交替行为,那么升高外加电压后斑图不会演化成超点阵斑图.如果单个放电丝的边界平滑、相互之间存在粘连并且运动方向总朝着几个固定的方向,单个放电丝的放电时间间隔有明显长短交替行为,那么升高外加电压将出现超点阵斑图.  相似文献   

10.
在纯空气或者空气-氩气混合气体介质阻挡放电装置中,观察到由中心点、顶点和连线组成的亮暗点蜂窝斑图.3套结构呈现出了不同的亮暗状态,表明它们的等离子状态和参数可能不同.本工作利用发射光谱法,研究了其分子振动温度和转动温度随氩气体积分数的变化情况.结果表明:在同一条件下,分子振动温度由低到高依次为中心点、顶点、连线,而转动温度则几乎相同.随着氩气体积分数的增加,3套结构的分子振动温度都呈下降趋势,转动温度则变化不大.  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.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

15.
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   

16.
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   

17.
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   

18.
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   

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.
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   

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