起偏器参量对磁场传感器光偏振态的影响

为了研究磁场传感器中出射光偏振态,用Poincaré球法分析了磁场传感器起偏角对光偏振态的影响.结果表明:Faraday材料中线双折射率的存在,使线偏振光演进为椭圆偏振光.无论外加磁场及Faraday材料线双折射率如何变化,当起偏角为45°时,出射偏振光始终为左旋椭圆偏振光;当起偏角为135°时,出射偏振光始终为右旋椭圆偏振光.其结果对偏振型磁场传感器的信号检测设计有一定的参考价值.     

高灵敏度离子分子的吸收光谱

介绍了光外差-磁旋转-速度调制吸收光谱技术对离子分子的研究,该技术综合了光外差光谱技术、磁旋转光谱技术和速度调制光谱技术三者的特点,形成可以对离子分子高灵敏度测量的光谱技术.该技术不仅保留了速度调制光谱技术对离子分子选择性探测的特点,避免了来自中性分子光谱线的干扰,同时利用光外差光谱技术降低来自光源的幅度涨落噪声,消除放电过程的干扰,再结合磁旋转光谱技术可以对顺磁性分子进行选择性测量以及进一步提高测量信噪比.介绍了光外差-磁旋转-速度调制光谱技术的基本原理、实验方案以及对N2+,CO+,H2O+等离子分子的测量研究结果.     

瞬态分子速度/ 浓度调制磁旋转光谱技术的选择特性

介绍了速度/浓度调制光谱技术和磁旋转光谱技术对瞬态分子的选择性探测．速度/浓度调制光谱技术可以实现对离子分子和瞬态中性分子的选择性探测；磁旋转光谱技术可以实现对顺磁性分子以及顺磁性态的选择性探测，并且可以明确指认转动谱带中的P支和R支谱线，有助于对复杂分子光谱线的分析．文中借助对N₂，O⁺₂，CN等瞬态分子的研究，阐述了速度/浓度调制光谱技术和磁旋转光谱技术的选择性探测原理．     

调制反射光谱在晶体研究中的应用

本文报导了用磁场调制反射光谱对磁光晶体进行的光学测量。实验结果表明,磁场调制反射光谱可有效地用于磁光晶体电子态结构的研究,从而提出了一种研究磁光材料光学特性的新的测试手段。     

频率调制对雷达线性调频脉冲压缩性能的影响

分析了频率调制对线性调频脉冲压缩雷达输出信号幅度和宽度的影响,包括匹配滤波器和加权滤波器两种情况.对利用正弦调相产生多个输出信号的方法进行了分析.推导了有关计算公式,给出了计算机仿真结果.结果表明,频率调制对雷达脉压输出信号幅度和脉宽的影响直接由频率调制失配因子χ(频率调制相对变化量与脉压比的乘积)决定.当χ足够大时,信号幅度减小倍数近似为0.54χ,信号脉宽增加倍数近似为χ/k(k>1时)或χ(k<1时).     

电场调制WS2单层分子薄膜光致发光行为

二维材料已经在多个领域得到应用,其中过渡金属硫化物(Transition metal dichalcogenides,TMDCs)因存在带隙而有望用于光电领域.将机械剥离法制备的WS2单层分子薄膜通过干法转移至两种微周期电极结构上,实验发现其光致发光信号受到外加偏压的调制.研究了常温和低温环境下外加偏压对WS2薄膜荧光...     

基于FPGA的多功能函数发生器

以C8051F040高性能单片机、AD9850和Altera Cyclone EPIC3T144 FPGA为核心,由控制模块、信号产生模块、放大模块、调制模块、键盘及LCD显示等模块组成的系统.实现了频率范围为20 Hz-20 MHz、步进为10 Hz.电压峰～峰值为6 yopp的正弦波信号输出;用FPGA产生的1 kHz的调制信号控制AD603放大器增益实现模拟幅度调制(AM)信号输出;根据调制信号幅度改变AD9850频率控制字实现模拟频率调制(FM)信号输出;用FPGA实现了2ASK和2PSK数字调制信号输出.     

AM信号到DSB信号的连续过渡与同步检波

现今模拟调制AM(Amplitude Modulation)信号到DSB(Double sideband)信号不能连续过渡的限制,是出于长期以来在许多文献中一直沿用的调幅信号调幅系数ma不能大于1的结论.采用四象限模拟乘法器和同步检波相结合的方法,从原理与技术上跨越了模拟调制AM调幅信号的调幅系数ma不能大于l的片面结论,给出了AM信号到DSB信号连续过渡进行调制和解调的原理电路.论证结果表明,调幅系数ma大于1的已调信号在调制端是可实现的,在接收端也是可以解调的.从而实现了AM信号到DSB信号的连续过渡与解调,因此也否定了一些对AM信号所作分析的历史结论.     

低频调制磁场对脑电节律的影响机理

神经细胞Ca2 内流及脑内5 HT、NE、DA等神经递质的变化影响了神经细胞放电速率,从而影响脑电节律.为揭示低频调制磁场对脑电节律产生影响的微观作用机理,检测了Wistar大鼠脑内神经递质的释放,电镜下观察了其神经突触形态的变化.实验结果显示,低频调制磁场作用引起大鼠脑内去甲肾上腺素(NE)、多巴胺(DA)、5 羟色胺(5 HT)释放显著增加(P<0.05),并观察到大鼠神经细胞内钙颗粒及释放神经递质的突触小泡数明显增加,提示低频调制磁场对人脑电节律的影响机理是其改变了Ca2 内流及脑内神经递质的释放量.     

植物细胞NO,Ca~(2+)和蛋白激酶的信号交叉

一氧化氮(NO)是植物体内重要的信号分子,生物和非生物的刺激都能使NO与胞内第2信使Ca2+和蛋白激酶产生相互作用.以动物细胞NO - Ca2+信号途径为基础,列举了植物NO信号途径中Ca2+和多种蛋白激酶的可能作用,论述了植物细胞中NO,Ca2+和蛋白激酶的信号交叉.     

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.     

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.     

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.     

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.     

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.     

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that