关于半波损失问题

从洛埃镜实验和维纳驻波实验中发生“半波损失”现象出发，利用菲涅耳公式，分析了当平面单色电磁波从光疏媒质入射到光密媒质时，在媒质的分界面处反射波电矢量Ｅ和入射波电关量Ｅ方向相反，这相当于附加λ／２光程差，习惯上称为“半波损失”。并以薄膜干涉中附加光程差加以说明．     

再论光波的半波损失

半波损失是大学物理中的重点和难点问题。根据半波损失定义明确了其产生条件,重申了半波损失和附加光程差的区别与联系,并结合薄膜干涉实例对附加光程差表达式作了针对性的分析,即附加光程差项可以取正号,也可以取负号,只是为了满足干涉级序数从零开始取值。     

半波损失和附加光程差

在许多大学物理教材中,对"半波损失"和"附加光程差"的问题都没有详细说明,给教学造成了一定的困难。本文根据半波损失产生的原因,总结了附加光程差是否存在的规律,希望对学生的学习有一定的帮助。     

附加光程差在薄膜干涉中的具体形式

利用半波损失原理，重新分析附加光程差在薄膜干涉中的形式，从而消除一般教材中对附加光程差描述的混乱，使读者对此问题认识得更彻底。     

小议薄膜干涉中的额外光程差

本文对薄膜干涉中两反射光之间的额外光程差的出现归结为“半波损失”提出了看法,并对额外光程差在什么条件下才等于λ/2进行了讨论。     

关于薄膜干涉中额外光程差的讨论

就薄膜干涉中两反射光间的额外光程差问题展开论述。首先给出半波损失的概念,强调入射光在掠入射或正入射两种情况下,反射光才可产生半波损失。其次讨论薄膜干涉中各种情况下反射光间的额外光程差。第1种情况是折射率为n2的薄膜处于折射率为n1的介质中,可分为n1〉n2和n1n2〉n3,n1n2n34种情况。分别讨论了反射光间是否存在额外光程差,并且对入射角的范围作了说明,同时更正了部分文献的错误。与某些教科书给出的结论不同,当媒质的折射率逐次变化时,也会存在一个额外光程差,但不是λ/2;而当薄膜上下表面物理性质相反时,也有额外光程差不为λ/2的特例。     

对菲涅耳公式应用的研究和探讨

利用菲涅耳公式阐述了反射时出现的半波损失，薄膜干涉时出现的额外光程差问题，解释了布儒斯特定律、全反射现象．     

光波场在2种介质界面反射时的半波损失

在波动光学中常常会遇到光波场在2种介质分界面上反射时的半波损失问题,而大多数教科书并未能从理论上阐明半波损失产生的条件和原因.从电磁场的基本理论出发,分析和讨论了光波场在两种界面上反射时的半波损失问题,从本质上全面,合理地解释了在实验中产生半波损失的实验结果.     

光波场在2种介质界面反射时的半波损失

在波动光学中常常会遇到光波场在2种介质分界面上反射时的半波损失问题，而大多数教科书并未能从理论上阐明半波损失产生的条件和原因。从电磁场的基本理论出发，分析和讨论了光波场在两种界面上反射时的半波损失问题，从本质上全面、合理地解释了在实验中产生半波损失的实验结果。     

关于周相突变和附加固相差

关于光波在两种不同媒质界面上反射时周相突变问题,一般光学教材写道:“光波从折射率小的光疏介质向折射率大的光密介质表面入射时,反射过程中反射光的位相变化π,它相当于多走了半波长,因而称这种现象为半波损失。”另外一些具有代表性的教材,结论基本上与此相同。这段话实际上还包含这样的含意:光在光密媒质中传播,遇到光疏媒质而被反射时,没有周相突变。这层含意在以上教材中推导薄膜干涉光程差公     

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.     

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.     

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.     

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。     

A computer generator for randomly layered structures

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

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.