核磁共振氢谱方法对红外光谱碳氟键伸缩振动变化的研究

采用傅里叶转换红外光谱方法测定了三种1,2-二-[β-(α-甲基-α'对位取代基苯基)噻吩]六氟环戊烯化合物Ⅰ、Ⅱ、Ⅲ的红外光谱.在确认主要红外吸收峰归属并对图谱进行解析的基础上观测到环戊烯环上的碳氟键吸收频率依化合物Ⅰ,Ⅱ,Ⅲ次序逐一相应增高,发生规律性变化.化合物Ⅰ:vas C-F=1 332.21cm-1,vs C-F=1 231.91 cm-1,δ C-F=1 159.99 cm-1;化合物Ⅱ:vas C-F=1 338.18 cm1,vs C-F=1 254.31cm-1,δ C-F=1 179.22 cm-1;化合物Ⅲ:vas C-F=1 360.99 cm-1,vs C-F=1 263.29 cm-1,δ C-F=1 194.00cm-1.对此不仅从红外光谱吸收原理进行了定性讨论,而且采用核磁共振谱测定化合物氢谱的方法给出了定量描述:化合物Ⅰ,Ⅱ,Ⅲ的H-1,H-2化学位移δ值,均为Ⅰ＞Ⅱ＞Ⅲ,反映出取代基引起苯环质子周围的电子云密度增加.因此可确认红外吸收的诱导效应与共轭效应共同作用是导致化合物环戊烯环上的碳氟键伸缩振动频率发生规律性变化的原因.这说明核磁共振氢谱是红外光谱解析的有力工具.     

Influence of interface structures on Sn thin film growth on Si(1 1 1) surface

Using coaxial impact collision ion scattering spectroscopy, we have investigated Sn thin film growth on Si(1 1 1)√3×√3-Sn and hydrogen-terminated Si(1 1 1) surfaces at room temperature. Sn formed crystalline film with β-Sn structure on Si(1 1 1)√3×√3-Sn surface, but on the hydrogen-terminated Si(1 1 1) surface, the epitaxial growth of Sn thin film was disrupted, and Sn grew as a polycrystalline film. The growth orientational relationship of the Sn film grown on Si(1 1 1)√3×√3-Sn surface was found to be

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. In the works, we found that interface structure plays a decisive role for the growth mode, crystallinity, and growth orientation of the growth of thin film.     

Gamma-ray transitions in Bi following the decay of Po

The decay of 5.7 h ²⁰⁷Po to levels in ²⁰⁷Bi has been studied using a Ge(Li) detector. Combining the relative gamma-ray intensities with previously established conversion electron intensities, K-conversion coefficients are determined. The multipolarities of 29 transitions are deduced from a comparison with theoretical conversion coefficients, thus establishing the following spins and parities for the excited levels:

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. A comparison with a recent shell-model calculation shows good agreement for all negative parity levels.     

Surface phonons of GaP(1 1 0) and InAs(1 1 0)

The dispersions of low energy surface phonon modes of GaP(1 1 0) and InAs(1 1 0) measured with inelastic He-atom scattering along the and 0 0 1 directions are presented. Aside from the Rayleigh mode, additional distinct acoustic modes are observed as well as indications of optical modes. Contrary to results for GaAs(1 1 0), a rocking mode was not observed. The experimentally determined phonon dispersions are in excellent agreement with recent ab initio calculations by C. Eckl, et al. [1].     

: Hadronic molecules in effective field theory

We consider the implications from the possibility that the recently observed state X(3872) is a meson–antimeson molecule. We write an effective Lagrangian consistent with the heavy-quark and chiral symmetries needed to describe X(3872). We explore the consequences of the assumption that X(3872) is a molecular bound state of D^*0 and mesons for the existence of bound states in the and channels.     

超导电性二流体模型的适用性

给出了由 2 B t=1α B t导出 2 B=1αB和由 js t=nse2m E导出 js=ensυs的证明 ,从而解决了 L ondon方程的理论缺陷 ,并讨论了 2 B t=1α B t与 2 B=1αB及 js t=nse2m E与 js=ensυs的适用性问题     

Kaon condensation and lambda–nucleon loop in the relativistic mean-field approach

The possibility of kaon condensation in high-density symmetric nuclear matter is investigated including both s- and p-wave kaon–baryon interactions within the relativistic mean-field (RMF) theory. Above a certain density, we have a collective state carrying the same quantum numbers as the antikaon. The appearance of the state is caused by the time component of the axial-vector interaction between kaons and baryons. It is shown that the system becomes unstable with respect to condensation of K– pairs. We consider how the effective baryon masses affect the kaon self-energy coming from the time component of the axial-vector interaction. Also, the role of the spatial component of the axial-vector interaction on the possible existence of the collective kaonic states is discussed in connection with Λ-mixing effects in the ground state of high-density matter. Implications of condensation for high-energy heavy-ion collisions are briefly mentioned.     

N-(2,3-二甲氧基苯基亚甲基)-4-硝基苯胺的合成及晶体结构

室温下由2,3-二甲氧基苯甲醛、4-硝基苯胺缩合反应制成了N-(2,3-二甲氧基苯基亚甲基)-4-硝基苯胺(1)。X射线单晶衍射仪测定了(1)的晶体结构,属于单斜晶系,P2(1)/c空间群,晶胞参数为:a=1.41919(14)nm,b=1.39745(12)nm,c=0.69710(7)nm,α=90°,β=102.365(1)°,γ=90°,V=1.3505(2)nm3,F(000)=600,Mr=286.28,Dc=1.408 g/cm3,μ=0.104 mm-1,R1=0.1138,ωR2=0.2621。     

Evolution of coupled classical fields

We study the evolution of the coupled scalar and fermion fields within the classical field theory. We examine the case of N coupled fields in (1+3)-dimensional space. The general expressions for the fields distributions are obtained. The particular case of two fields in (1+1)-dimensional space is carefully studied. We obtain the expressions for the averaged fields intensities and show that in the relativistic limit they are similar to the usual transition probabilities formulae of neutrino oscillations.     

Vertex ring-indexed Lie algebras

Infinite-dimensional Lie algebras are introduced, which are only partially graded, and are specified by indices lying on cyclotomic rings. They may be thought of as generalizations of the Onsager algebra, but unlike it, or its sl(n) generalizations, they are not subalgebras of the loop algebras associated with sl(n). In a particular interesting case associated with sl(3), their indices lie on the Eisenstein integer triangular lattice, and these algebras are expected to underlie vertex operator combinations in CFT, brane physics, and graphite monolayers.     

Surface structure of low-coveraged Cs on Si(0 0 1)-() system

Alkali metals (AM) on semiconductors have been investigated as a simple model system for the metal-semiconductor interfaces due to their simple electronic structures. Especially, cesium (Cs) on Si(0 0 1) surface has been studied with various experimental techniques. In this study, we investigated the atomic structure of initial Cs adsorption on Si(0 0 1)-(2×1) surface using coaxial impact collision ion scattering spectroscopy. When Cs atoms are adsorbed on Si(0 0 1)-(2×1) up to 0.2 ML at room temperature, the initial adsorption site is on-top T3 site with poor periodicity and the length of Si dimer is reserved as in the clean Si(0 0 1) surface. It is also found that Cs atoms adsorbed on Si(0 0 1) surface with a height of 2.83±0.05 Å from the second layer of Si(0 0 1) surface.     

Materials with a desired refraction coefficient can be made by embedding small particles

A method is proposed to create materials with a desired refraction coefficient, possibly negative one. The method consists of embedding into a given material small particles. Given n₀(x), the refraction coefficient of the original material in a bounded domain , and a desired refraction coefficient n(x), one calculates the number N(x) of small particles, to be embedded in D around a point xD per unit volume of D, in order that the resulting new material has refraction coefficient n(x).     

Dose distribution of carbon ions in air assessed using imaging plates and ionization chamber

A system to expose biological specimens to medium-energy (2.6–6.0  MeV/u) irradiation has been developed at the NIRS-HIMAC. In order to determine the beam energy or LET at the irradiation position in air, the dose distribution for 6.0  MeV/u carbon beam has been obtained using a secondary electron monitor and a flat-type ionization chamber by using air as the energy absorber. Imaging plates were applied to assess the beam profile distribution. The intensity of photo-stimulated luminescence (PSL) was found to be almost proportional to the energy deposited within the sensitive layer of the imaging plate. It has been confirmed that a uniform irradiation field can be produced (about ±5% within 20 mm in diameter) at low-intensity exposure from 10¹ to . Long-term beam stability in the low-intensity condition has also been demonstrated. As a consequence, the methodology for uniform, stable and low-intensity beam exposure has been established, and the continuously variable linear energy transfer (LET) values have also been obtained by changing the distance from the endcap of beamport, for biological studies.     

Chiral dynamics and antikaon-nuclear quasibound states

Recent developments are summarised concerning low-energy interactions as they relate to the possible existence of antikaon-nuclear quasibound states. An exploratory study of antikaons bound to finite nuclei is performed, with emphasis on the evolution of such states from light to heavy nuclei (A = 16–208). The energy dependent, driving attractive interactions are constructed using the s-wave coupled-channel amplitudes involving the Λ(1405) and resulting from chiral SU(3) dynamics, plus p-wave amplitudes dominated by the Σ(1385). Effects of Pauli and short-range correlations are discussed. The decay width induced by K⁻NN two-body absorption is estimated and found to be substantial. It is concluded that -nuclear quasibound states can possibly exist with binding energies ranging from 60 to 100 MeV, but with short life times corresponding to decay widths of similar magnitudes.     

Peakon, compacton and loop excitations with periodic behavior in KdV type models related to Schrödinger system

In this Letter, the linear variable separation approach is successfully extended to (1+1)-dimensional Korteweg–de Vries (KdV) type models related to Schrödinger system. Some significant types of solitons such as compacton, peakon and loop solutions with periodic behavior are simultaneously derived from the (1+1)-dimensional soliton system by entrancing appropriate piecewise smooth functions and multivalued functions.     

Flux and energy distribution of axial protons emitted from the hydrogen plasma focus

Experimental results and theoretical studies show that protons from the hydrogen plasma focus are emitted predominantly in the axial direction. In this work the results of the flux and energy distribution measurements of the axial protons using CR-39 detector are presented. The main purpose of the experiment is to test the suitability of a plasma focus device as a source for (p,) nuclear reactions, especially and .     

Measurement of indoor radon levels in Erbil capital by using solid state nuclear track detectors

Radon alpha activity concentration has been measured in 28 homes in the Erbil Capital-Iraqi Kurdistan region during the autumn season by using time-integrated passive radon dosimeters containing CR-39 solid state nuclear track detectors “SSNTDs”. The radon activity concentrations in these homes range from (10.33–90.34) with an average of . The average absorption effective dose equivalent for a person living in homes for which the investigation were done was found to be , obtained by using an equilibrium factor of 0.5 and an occupancy factor of 0.8. The average lung cancer cases per year per 10⁶ person was found to be 23±12.     

Mössbauer effect studies of the 74.5 keV level of Dy

Recoilless absorption measurements of the 74.5 keV γ-rays of ¹⁶¹Dy were carried out using

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absorbers. The analysis of the absorption spectrum obtained with the nitrate absorber yielded a value of 1.38 ± 0.02 for the ratio of the g-factor of the 74.5 keV and the ground levels of ¹⁶¹Dy and a value of 0.58 ± 0.04 for the corresponding ratio of the quadrupole moments. Relying on previous measurements of the ground level moments, the values derived for the magnetic and quadrupole moments of the 74.5 level are −0.377 ± 0.012 n.m. and 1.5 ± 0.2 b, respectively. These values are compared with the values predicted by nuclear theory. The isomeric shift between DyNi₂ and absorbers was found to be 0.9 ± 0.2 mm/sec.     

An analytical approach to the design of electrodes in high-power, fast-transverse-flow lasers

Usually, the design of the electrodes of fast-transverse-flow CO₂ lasers relies more on experimental data than on theoretical analysis. Traditional systems sustain a stable, high-power discharge but the current distribution generates a peaked, non-uniform small-signal-gain pattern. We present a theoretical model suitable for the design of electrodes that achieves a quasi uniform gain distribution. The analysis, based on a two-temperature model and the gas-transport equations, computes the electron density that supports a flat gain pattern. Combining the desired electron density with the electron-balance equations, the model determines the required electric field. The results were used to design a new set of electrodes for a home-made fast transverse flow CO₂ laser. A stable, large volume discharge () with very good uniformity was obtained. The resulting gain distribution was registered in a bi-dimensional map. The peak gain rose from , attained with the old electrode set, to with the new one and the gain showed a homogeneous profile.     

Density functional theory analysis of the Ni(1 1 0)c(2 × 2)-CN surface phase

Density functional theory slab calculations have been used to investigate the structure of the Ni(1 1 0)c(2 × 2)-CN adsorption phase. The results show excellent agreement with experimental quantitative determinations of this structure by photoelectron diffraction and low energy electron diffraction. In particular, they show that a lying-down orientation with the C–N axis along [0 0 1] perpendicular to the close-packed Ni rows on the surface is strongly favoured over end-on adsorption (with the C–N axis perpendicular to the surface). This geometry is also favoured over a lying-down geometry with the C–N axis aligned along the azimuth, as originally proposed for this system and supported by cluster calculations.