IR Properties of Randomly Sea Surfaces

Sea surfaces should be considered as randomly rough surfaces at the infrared(IR) and optical bands. The geometric model of sea surfaces has been obtained by using image processing. Based on the electromagnetic scattering theory, the Laser Radar Cross Section(LRCS) for the sea surfaces is analyzed at IR band and the scattering properties of the sea surfaces have been gotten.     

瘦长红珊瑚的振动光谱研究

瘦长红珊瑚是台湾贵珊瑚中最主要的品种,其颜色分布独具特色。以瘦长红珊瑚为研究对象,采用电子探针、X射线粉晶衍射、红外光谱和拉曼光谱对其进行测试分析。结果显示样品的矿物成分为高镁方解石,次要成分的含量稳定,样品中的生物成因方解石存在晶格畸变。实验探测到的代表有机质成分的1 517/1 128cm-1和1 296/1 016cm-1成套谱峰表明样品的红色与该有机成分有关。     

Absolutely continuous spectrum for random Schrödinger operators on the Bethe strip

The Bethe strip of width m is the cartesian product $\mathbb {B}\times \lbrace 1,\ldots ,m\rbrace$, where $\mathbb {B}$ is the Bethe lattice (Cayley tree). We prove that Anderson models on the Bethe strip have “extended states” for small disorder. More precisely, we consider Anderson‐like Hamiltonians $H_\lambda =\frac{1}{2} \Delta \otimes 1 + 1 \otimes A\,+\,\lambda \mathcal {V}$ on a Bethe strip with connectivity K ≥ 2, where A is an m × m symmetric matrix, $\mathcal {V}$ is a random matrix potential, and λ is the disorder parameter. Given any closed interval $I\subset \big (\!-\!\sqrt{K}+a_{{\rm max}},\sqrt{K}+a_{\rm {min}}\big )$, where a_min and a_max are the smallest and largest eigenvalues of the matrix A, we prove that for λ small the random Schrödinger operator H_λ has purely absolutely continuous spectrum in I with probability one and its integrated density of states is continuously differentiable on the interval I.     

Marked length rigidity of rank one symmetric spaces and their product

In this paper we show that if two Zariski dense representations, from a group G into Iso(X) where X is rank one symmetric space, have the proportional marked length spectrum, then they are conjugate. As a generalization we show that a Zariski dense representation into the isometry group of the product of rank one symmetric spaces is determined by the marked cross ratio.     

On Transfer Operators for Continued Fractions with Restricted Digits

For any non-empty subset I of the natural numbers, let _I denotethose numbers in the unit interval whose continued fractiondigits all lie in I. Define the corresponding transfer operator for , where Re (rß) = _I is the abscissa of convergence of the series . When acting on a certain Hilbert space H_I, rß, weshow that the operator L_I, rß is conjugate to an integraloperator K_I, rß. If furthermore rß is real,then K_I, rß is selfadjoint, so that L_I, rß: H_I, rß H_I, rß has purely real spectrum.It is proved that L_I, rß also has purely real spectrumwhen acting on various Hilbert or Banach spaces of holomorphicfunctions, on the nuclear space C [0, 1], and on the Fréchetspace C [0, 1]. The analytic properties of the map rß L_I, rßare investigated. For certain alphabets I of an arithmetic nature(for example, I = primes, I = squares, I an arithmetic progression,I the set of sums of two squares it is shown that rß L_I, rß admits an analytic continuation beyond thehalf-plane Re rß > _I. 2000 Mathematics SubjectClassification 37D35, 37D20, 30B70.     

太赫兹目标RCS缩比测量技术

论述了国外基于微波上倍频、激光下变频、THz时域光谱三种典型太赫兹波目标雷达散射截面(RCS)缩比测试系统的构成、技术特点和应用范围。采用固态器件、基于微波上倍频技术集成研制了宽带太赫兹低频端目标RCS测量系统,采用基于扫频的时域法RCS测量技术和小角度旋转目标雷达合成孔径（ISAR）成像方法对小目标进行了电磁散射特性测量,获取了目标RCS和二维散射成像信息。     

双路输出超宽谱高功率微波驱动源Tesla变压器

为实现25 GW级双路输出超宽谱高功率微波驱动源的小型化,选择研制了一种与双筒脉冲形成线(Blumlein线)相配一体化的带有开路磁芯的Tesla变压器,作为初级脉冲功率源。进行了Tesla变压器的理论分析,利用简化的磁路模型研究了Tesla变压器初次级线圈电感等电参数的估算方法,给出了Tesla变压器磁芯截面的估算和磁芯制作方法。该Tesla变压器最大输出电压880 kV,充电时间约20 s,耦合系数约0.95,实验结果与理论设计相符。     

4-乙酰基吡啶红外和拉曼光谱的密度泛函理论研究

4-乙酰基吡啶是一种重要的添加剂和医药中间体。在室温条件下使用液膜法测定了4-乙酰基吡啶的红外光谱和拉曼光谱,结合密度泛函理论在高水平基组条件下计算得到的稳定构型、振动频率和各谱带的势能分布,对观测到的谱带做出了全面指认和详细分析,为该类化合物的实验鉴别提供了理论依据。     

Optical observation of ion displacement in pyroelectric BaMnF4

Two anomalous behaviors are observed in the Raman spectra of BaMnF₄ at room temperature. One is that the number of Raman lines is smaller than that expected for the orthorhombic crystal structure with C _2ν ¹² symmetry, the other is that, of the b(aa)c, a(bb)c, and b(cc)a scattering geometries giving the same A₁-symmetry spectrum, the number of Raman lines in the b(aa)c spectrum is considerably smaller than those in the other two spectra. It is suggested that rotation of MnF₆ octahedra about c-axis occurring in the orthorhombic phase is responsible for the former behavior, and Ba²⁺-ion displacement along a-axis for the latter one.