双球面声学透镜优化设计

对双球面声学透镜在不同曲面形状参数条件下的声场进行数值计算，分析了透镜面形参数与声场分布特征的关系；根据在声场中尽可能长的范围内获得声束宽度较小、旁瓣水平适中的聚焦声束的要求，给出了双球面声透镜的优化面形参数。     

一种空心光束的简易实现方法

利用玻璃毛细管作为空心波导,研究聚焦光束在其中的传输特性.实验结果表明:当聚焦光束以正射方式入射到空心玻璃毛细管波导时,经玻璃毛细管传输后的聚焦光束由原先的高斯光束变成零阶贝塞耳光束;而当聚焦光束非正射入射时,即聚焦光束以其光轴与毛细管中心细孔的中心轴成某一角度入射时,经传输后的聚焦光束由原先的高斯光强分布变为空心光强...     

球面压电式ESWL聚焦的实际焦点的数值分析

为了计算球面压电陶瓷型ESWL(extracorporeal shock wave lithotripsy)发射的球面冲击波在球心附近的实际动力学焦点,利用CCW(chisnell-chester-whitham)射线方法的一种离散格式,计算了对于不同张角球面压电陶瓷型ESWL冲击波聚焦问题的一些数值解.数值结果指出了球面压电陶瓷型ESWL几何中心即球心附近的冲击波聚焦特性,实际的动力学焦点不在球心而有所偏移.随着张角的增大,聚焦能量增加,轴线上的压力比也随之增加.     

向井外地层中扫描辐射声场的数值模拟

应用实轴积分方法研究了实现由充液井孔中的相控线阵声波辐射器向井外地层中扫描辐射声场的方法. 研究表明, 通过改变井孔中的相控线阵声波辐射器的阵元个数、相邻阵元间激励信号的延迟时间等参数可以控制辐射声束的角宽和入射于井壁的入射角. 当辐射器产生的声束以小于第一临界角的偏转角入射到井壁上后, 在井外地层中产生的纵波的偏转角近似满足平面波入射于平面界面时的折射定律. 当井孔中的相控线阵的辐射声束角宽较小, 且声束偏转角小于第一临界角时, 可以假设将相控线阵置于无井孔的均匀固体中, 利用固体中相控线阵的指向性函数直接计算井外声场的空间分布. 向井外地层中扫描辐射声场技术可以用于提高反射声波测井和井间声波勘探的空间分辨率和信噪比.     

复合静电聚焦—偏转系统的渐近象差

本文提出并讨论了复合聚焦——偏转系统的渐进象差概念,并推导了复合静电聚焦——偏转系统的一级渐进色差和三级渐近几何象差的公式.这些渐进象差系数均可表为物距X_0或放大率的倒数m 的多项式的形式,便于研究计算任意物象位置时的象差和设计计算带有多个聚焦——偏转器的静电电子和离子束探针系统.     

两种色散特异材料双层结构中的法诺共振机制

单负特异材料双层结构中,由于分离式的反射共振和宽带的强反射之间发生的法诺型干涉,在反射谱中出现了非对称法诺谱。当光斜入射到单负特异材料异质结时,分离式的反射共振发生在单负特异材料色散磁导率接近于零的频率点。通过解析和数值分析得到,法诺型反射的非对称因子与入射角是密切相关的。     

亚波长光栅的零级反射特性研究

从严格耦合波衍射理论出发,在不同入射角、方位角和光栅参数下的情况,计算了矩形亚波长光栅零级反射效率随入射光波长的变化.通过计算结果,找出相对合理的光栅参数,使得当入射光的入射角或方位角发生变化时,光栅反射出不同波段的光,即反射出不同颜色的光.这些研究可应用于防伪技术,为设计和制作防伪光栅提供了设计依据.     

激光在弯曲液面的反射效应及应用

基于激光在润湿效应形成的凹形弯曲液面上边界反射,研究了凹形弯曲液面的特性.结果表明,当平行激光束入射到由圆柱形玻璃管壁润湿效应形成的凹形弯曲液面上时,边界反射可产生特殊的反射图样,且图样半径随入射光束半径的增大迅速变大.通过测量反射图样的半径和入射光束的半径,可实时描绘弯曲液面的性质.利用弯曲液面的边界反射可测得弯曲液面的斜率曲线、弯曲液面上升的最大高度和接触角.     

复杂工件内部缺陷超声柔性探头检测数值仿真

根据相控超声波一维阵列柔性探头聚焦原理,针对复杂表面不锈钢工件的内部缺陷检测,基于CIVA无损检测仿真软件,建立了上表面为半径150 mm的圆弧曲面、下表面含有三角形槽和圆形槽的复杂工件模型,分别以10 mm×10 mm分层缺陷及直径2 mm贯穿孔缺陷检测为例,定性及定量地比较了声束偏转及单点聚焦2种聚焦模式在缺陷检测上的区别.结果表明单点聚焦模式可以较好地获得缺陷在定位、定量及定性方面的信息,声束偏转聚焦模式仅能获得缺陷在定性方面的信息,采用2种聚焦模式结合的检测方法,可以获得较好的缺陷检测效果.     

维恩滤质分析器的聚焦和象差理论

本文对维恩滤质分析器(Wien filter analyzer)即交叉场分析器的电场和磁场分布特点,粒子轨迹、聚焦成象性质和象差进行了系统的理论研究;推导了分析器的二级几何象差与一级色差的一般公式,并特别研究了具有类似圆透镜聚焦性能的双向聚焦维恩滤质分析器的情形;给出了横向场具有矩形分布时一级色差系数和二级孔阑象差系数的解析公式.     

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

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.     

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.     

Design and analysis of generic LBS application developing platform

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.     

橡胶颗粒沥青混合料低温抗裂性试验研究

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.     

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。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

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.     

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.