基于平行光束的后向散射光电感烟探测器的研究

简要介绍了光源辐射功率和波长、粒子浓度、粒径、散射角、散射体积和光敏元件的受光面积等对散射光电感烟探测器的影响，散射光强度与散射角度和粒径的关系，并说明了利用后向散射来设计出对黑烟和白烟都敏感的光电感烟探测器成为可能．     

基于Monte Carlo模拟设计MicroSPECT针孔准直器

为使小动物成像专用的MicroSPECT(micro single photon emission computed tomography)达到预期的分辨率和灵敏度指标,基于Monte Carlo方法对针孔准直器和成像系统参数进行设计并确定了两套设计方案。方案A保证灵敏度不低于9.19×10-6s-1.Bq-1,且视野中心位置的分辨率不差于1.0 mm;方案B在保证分辨率好于1.2 mm的前提下,可达到5.86×10-5s-1.Bq-1的灵敏度。进一步采用Monte Carlo方法估计了γ光子的准直器孔壁穿透效应和Compton散射效应对投影数据的影响。结果表明:穿透效应在方案A和B中对投影数据的贡献分别为28.6%和40.4%,而散射光子的贡献分别为12.4%和12.9%。     

二次康普顿散射和产生双光子的康普顿散射

从康普顿散射的基本原理出发,基于能量、动量守恒定律和相对论效应,首先讨论了康普顿散射中的二次散射,得出波长的改变量不仅与散射角有关,还与入射光子的波长(频率)有关;其次讨论了产生双光子的康普顿散射,由于这种散射的复杂性,只选取了两种特殊情形来讨论,得出散射光子的频率不仅与两个散射光子的散射角有关,还与入射光子频率有关,单一频率的入射光子发生双光子散射后,散射光子波长的改变还可能是连续变化的;康普顿散射实验说明二次散射和双光子散射的发生是可能的。     

N光子集团的Compton散射截面

采用量子化辐射场与相对论电子作用的模型,从微扰论得出的跃迁概率表达式出发,导出了n光子集团与电子发生Compton散射的跃迁概率表达式.进而研究了 n光子集团Compton散射的光子散射截面性质,得出了双光子Compton散射的光子散射截面的具体表达式,结果表明n光子Gompton散射的光子微分散射截面不仅与散射角(光子入射方向与散射方向的夹角)有关,还与入射光场的光子数密度以及初始电子的能量有关.     

极端相对论电子对横等离子体波的散射

计算了极端相对论电子对横等离子体波的Compton散射与非线性散射,给出了极端相对论电子对横等离子体波的散射概率及散射谱,该谱与真空中极端相对论电子对单色入射光的逆Compton散射谱有着明显的不同,且出射波极大频率与入射波频率之比也与真空中逆Compton散射不相同。     

纤维蛋白原与白蛋白的光散射特性

利用激光散射法对健康人血中的纤维蛋白原及生物制品白蛋白的光散射特性进行了研究，测量了不同浓度下这两种大分子的散射光强和透射光强，并给出了相应的微观散射系统，对研究血中成分的微观特性和基于光散射方法设计医疗检测仪器提供了理论依据。     

水下距离选通成像系统后向散射光的计算

为了实现在室内测试距离选通成像系统的分辨力，建立了后向散射光模型．分析并给出了典型的脉冲激光照明的水下距离选通成像系统的光学几何结构和相关参数．采用辐射传输理论建立了水下距离选通成像系统的后向散射光模型．编制了相应的计算机程序，根据典型系统参数计算并绘制了系统的重叠系数和后向散射光随时间的变化曲线．结果表明，到达探测器的后向散射通量随时间快速上升，达到最大值后又快速下降，5ns激光脉冲的后向散射辐射通量集中分布在20ns时间间隔内。     

三维任意几何光子成像系统的散射修正及图像重建方法

在客体材料密度重建过程中考虑散射光子的影响,研究了在重建过程中通过迭代扣除散射贡献进行散射修正的重建方法.针对三维任意几何结构问题,利用AutoCAD的二次开发功能实现几何前处理,开发了用于散射量计算的快速光子输运计算程序及基于三维任意几何结构的迭代法图像重建程序(IPOR).通过与蒙特卡罗程序MCNP进行数值比较,可知文中采用的散射修正方法在达到与蒙特卡罗方法相当精度的同时,其计算效率可提高2个数量级.重建计算结果表明,IPOR的重建精度远高于未进行散射修正的直接求解法的重建精度.     

偏振光在散射介质中的传播与成像

偏振光在散射介质中传播的过程中其时间、空间、方向、相干性和偏振等物理指标的变化规律，是强散射介质光学成像研究的基本问题，对发展生物医学光学新技术和新应用具有重要意义．从偏振光散射与传播基本过程出发，利用Monte Carlo方法，模拟偏振光子在强散射介质中传播的统计规律，并结合仿体和生物组织样品的实验，分析介质中散射粒子的形状、空间取向、组成和空间分布等因素对偏振光子传播和成像的影响；比较了在光路中采用角度、空间和偏振等门控技术之后对散射光子的抑止作用，以及对成像质量的改善。     

Compton散射下激光等离子体与自生磁场对电子的加速

应用电子与多光子集团非线性Compton散射模型,对多光子非线性Compton散射下激光等离子体和自生磁场对电子的加速进行了理论分析和数值模拟.结果表明,不仅由Compton散射光与入射光形成的耦合光以及耦合光与等离子体相互作用形成的自生磁场所构成的混合场能使做回旋共振运动的电子在较短的长度内加速到很高的能量,而且注入电子的初始参数及耦合光的参数对电子加速亦有较大影响.     

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。     

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.     

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.