大气压氩气周期性突起的放电特性及其产生机制研究

大气压等离子体射流可以在空气环境中产生等离子体羽.与通常产生的锥状等离子体羽不同,利用低频偏置正弦电压激励大气压氩气等离子体射流,等离子体羽呈现周期性突起.利用电学、光学及光谱学手段对突起状等离子体羽的放电特性及其形成机制进行了研究.结果表明,等离子体羽长度随着气体流量增大而增大.放电的波形表明每一个电压周期存在一次放电,且它出现在电压的负半周期.通过高速影像发现,突起状等离子体羽对应沿着气流传播的负流光.射流喷口附近存在周期性的强放电,它为下游提供了空间规律性分布的活性粒子.该活性粒子能增强流光的传播,表现为等离子体子弹的直径增大,因此形成空间周期性的突起.利用光学发射谱,测量了电子激发温度的空间分布及平均电子激发温度随着气体流量的变化关系,并对这种变化趋势进行了定性解释.     

光谱法研究大气压氩气等离子体射流的气体温度

采用针-板介质阻挡放电结构的射流装置,在大气压空气环境下产生了氩气等离子体羽.通过采集外加电压、电流及发光信号发现,在电压正、负半周期各有一个电流脉冲.就电流峰值而言,正脉冲大于负脉冲.等离子体羽的发射光谱包含氩4p→4s跃迁谱线、氮分子第二正带系(C~3Π_u→B~3Π_g)、带头位于308.0 nm的OH转动谱线(A~2Σ~+→X~2Π)和777.4 nm的氧原子发射谱线.通过拟合N_2(C~3Π_u→B~3Π_g)和OH的转动光谱,可以获得等离子体羽的气体温度.研究发现,拟合N_2第二正带系得到的气体温度要高于拟合OH转动光谱得到的气体温度.分析表明,氩的亚稳态Ar(4s)能够将能量转移给基态N_2,使其跃迁到高转动能级的激发态(C~3Π_u).因此,这种传能导致具有高转动能级氮分子布居数的增加,进而导致利用其计算得到的气体温度相对较高.利用OH的转动谱带拟合计算了气体温度,并研究了气体温度随实验参数的变化.结果表明,增大峰值电压及气体流量导致气体温度升高,但增加驱动频率气体温度降低.     

电场与流场夹角对大气压等离子体羽动力学的影响

通过设计新型的交流激励氩气等离子体射流,在棒电极的下游产生了大气压等离子体羽.该射流与平行场射流和交叉场射流不同,它的电场与流场夹角可以在一定范围内改变.结果表明,在同一外加电压时,下游羽长度随着夹角的增大而减小.对于不同的夹角,外加电压的正、负半周期各对应着一个放电脉冲,并且放电脉冲强度随着夹角的增大而减小.利用高速影像,研究了夹角对等离子体羽动力学的影响.发现一个放电脉冲对应着一个子弹的传播过程,子弹的传播速度先增大后减小,并且其最大传播速度随着夹角的增大而减小.基于碰撞辐射模型,利用谱线强度比的方法研究了电子激发温度的空间分布,它反映出了净电场的空间分布.结果表明它与子弹传播速度的空间分布一致.     

电极尺寸对射流等离子体放电的影响及其在涤纶亲水研究中的应用

大气压脉冲介质阻挡放电射流等离子体中,羟基活性粒子的生成和调控对于等离子体在材料表面改性方面的应用具有重要意义,而羟基活性粒子的形成和调控又与放电结构密切相关。研究了接地电极宽度对大气压脉冲放电射流等离子体的影响：通过改变接地电极宽度,探究其对射流长度、放电强度的影响;通过增强型电荷耦合器件(ICCD)对放电时空演化进行分析;通过发射光谱分析放电产生的特征谱线。结果表明：当接地电极的宽度为1.5 cm时,射流长度最长;在射流3 mm处,有较强的羟基活性粒子浓度。利用大气压脉冲射流等离子体处理涤纶织物表面,验证了气相等离子体中羟基含氧基团与涤纶表面亲水处理效果的正相关性,为等离子体中活性粒子的控制和开发工业用等离子体源提供了参考。     

光谱法研究盐溶液浓度对辉光放电活化液体的影响

大气压辉光放电具有低气压辉光放电的均匀性和较高的化学活性,且摆脱了真空装置的限制.液面上的大气压辉光放电除了具有以上优点外,还具有活性粒子浓度高等优势,因此在材料改性、生物医疗等领域具有非常广泛的应用前景.本文采用针-液体电极直流放电装置,在液体电极上方产生了大气压辉光放电,并用于活化不同浓度的NaCl溶液.发射光谱表明,不同浓度液体电极放电均包含N₂的第二正带系、N⁺₂的第一负带系、OH自由基和O I.基于发射光谱,测量了液面附近的氧原子谱线强度、谱线强度比I_391.4/I_337.1和振动温度.利用吸收光谱测量了O₃浓度.发现它们均随着放电电流的增大而增大,且在一定电流下,随盐溶液浓度减小而增大.经过相同活化时间,溶液的H₂O₂浓度随着放电电流的增大而增大.在一定放电电流下,H₂O₂浓度随盐溶液浓度增大而减小.     

空气暖等离子体射流发生器降温系统设计

为了更好满足等离子体射流发生器便携、易操控、应用环境多样性等要求，针对传统水冷笨重、难以移动等缺点，在发生器电极、冷却结构等方面设计了以空气为工作气体并且兼具冷却功能的气体回路便携式暖等离子体射流发生器，研究了工作气体流量、放电频率、放电电压对等离子体射流温度的影响规律.研究发现，冷却气体的引入明显降低了射流温度，在5.5 kV电压、22 kHz频率和7 L/min流量条件下，冷却气体的引入使得射流温度降低了302℃.射流温度随着气体流量和放电频率的增加而减小、随放电电压的增加而增加.相对于放电频率或放电电压，射流温度的降低对气体流量依赖性更强.     

轴对称等离子体射流的实验研究

等离子体射流具有广泛的应用前景。建立了轴对称等离子体射流的模型,得出层流状态下等离子体射流的长度与流量成正比。采用Ne、He、Ar在大气压下用介质阻挡放电的手段得到了等离子体射流,发现层流状态下等离子体射流长度与模型结论一致,但是随着激励电压的升高和气体流量的增大,等离子体射流会发生从辉光放电到丝状放电、从层流到湍流的转捩,射流长度会先增大后减小;工作气体的不同对等离子体射流的性质也有重要影响。     

介质阻挡放电中等离子体子弹的速度

利用针板介质阻挡放电装置,采用光学方法对大气压长间隙空气放电的等离子体羽特性和等离子体子弹速度进行了研究.结果表明:改变外加电压等离子体羽长度会发生变化.利用光电倍增管采集光信号对等离子体子弹速度进行了研究,发现等离子体子弹的速度与针板间距、外加电压以及针尖直径有关.利用光谱仪采集放电的发射光谱,发现放电等离子体中存在OH自由基、氧原子等多种活性粒子,表明该放电在生物医疗领域具有重要的应用价值.     

外加电压参数对大气压等离子体射流形貌的影响

大气压等离子体射流可以在开放的空气环境中产生富含多种活性粒子的低温等离子体羽,在材料合成、表面改性、生物医疗、环境保护等多种领域具有广泛的应用前景. 等离子体羽的形貌与活性粒子的时空分布有关,研究其形貌对等离子体射流的应用具有重要意义.针对目前等离子体形貌还不够丰富的问题,本文利用氩气等离子体射流,通过改变外加电压参数(电压峰值、驱动频率和偏置值)产生了几种形貌的等离子体羽(弥散圆锥状、丝加晕形、念珠串状和空心锥状),从而进一步丰富了等离子体羽的形貌.通过对比放电的电压和发光信号波形,发现除丝加晕形等离子体羽外,其他3种等离子体羽在每个外加电压周期均放电1次.不同的是,弥散圆锥状和念珠串状等离子体羽的放电出现在电压负半周期,为负放电.而空心锥状等离子体羽的放电出现在外加电压正半周期,为正放电.丝加晕形等离子体羽每个电压周期存在1个负放电和1个正放电.此外,还利用高速成像设备对这几种形貌等离子体羽的时空演化进行了研究.相关结果表明,负放电对应负流光的传播过程,而正放电对应正流光的过程.视觉上不同形貌的等离子体羽是正流光、负流光及其组合时间叠加的结果.本文的结果对大气压等离子体射流中等离子体羽形貌的深入研究及流光动力学的进一步发展均具有重要价值.     

乙醇掺氮放电大气压等离子体射流的光谱特征研究

对乙醇放电的大气压等离子体射流进行了研究.用发射光谱(OES)法观察了等离子体光谱中的C,CN,CH和C_2基团.在Ar与乙醇混合物等离子体的光谱中,分别在473.7,516.4和563.5nm处出现了3个明显的C_2分子谱线;在388.3nm出现了CN自由基分子谱线.掺入氮气后在422nm处出现了新的CN谱线,C_2谱线则只出现在516.4nm处,473.7和563.5nm处的C_2谱线明显消失.当乙醇含量不变时,随着氮气流量的增加,可以显著地提高CN基团的谱线强度,同时有效地抑制C_2基团的谱线强度.     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-