The dependence of muon intensity on the geomagnetic latitude

The vertical momentum spectrum of cosmic-ray muons has been determined by a counter controlled neon-hodoscope in the spectral region (0.2–3) Bev/c at geomagnetic latitude 12 °N. The observed spectrum agrees satisfactorily with the calculated spectrum of Olbert for muon momentum above 1.8 Bev/c. Below about 1.8 Bev/c, the measured spectrum exceeds slightly the theoretical spectrum of Olbert, calculated for the same geomagnetic latitude. The measured spectrum agrees with the experimental spectrum of Allkofer at 9 °N, but is somewhat below the spectrum obtained by Hayman in the low momentum region at 57.5 °N. This shows that there exists a latitude dependence of the low momentum muon spectrum. The estimated integral intensity of muon of momentum ≧320 Mev/c is found to be 7.3×10^?3 cm^?2 sec^?1 str^?1 which agrees with the value of other investigators^1–9.     

Far ultra-violet absorption bands of osmium (IV), iridium (IV), platinum (IV) hexahalides

The gas phase electron resonance spectrum of SeO in its ³Σ and ¹Δ states has been studied. Values of the rotational constant B ₀ and ‘spin-spin’ splitting parameter λ in the ³Σ state, previously determined from the ultraviolet spectrum, are shown to be consistent with the electron resonance results, and we are also able to estimate the spin-rotation interaction constant. In addition, the ³Σ spectrum shows ⁷⁷Se hyperfine structure. The ¹Δ spectrum yields values for the rotational constant (and hence bond length) and rotational g factor.     

Possible origin and spectrum of ultrahigh-energy cosmic rays

The complicated form of the cosmic-ray spectrum recorded in the energy range 10¹⁷–10²⁰ eV by giant detector arrays is analyzed. It is shown that the spectrum in the region 10¹⁸–10¹⁹ eV is apparently identical to the injection spectrum with power-law exponent approximately equal to 3.2–3.3. The flat component in the region (3.2–5)×10¹⁹ eV is due to the braking of extragalactic protons by relict photons. The spectrum apparently has no blackbody cutoff at energies above 3.2×10¹⁹ eV. Pis’ma Zh. éksp. Teor. Fiz. 65, No. 10, 729–733 (25 May 1997)     

Measurement of the beta spectrum of the 0− (120 keV) state of16N

We have measured the beta spectrum of the 0^?(120 keV,t _1/2=5.25 μs) state of¹⁶N. The response function of our detector has been measured, parameterized and then fitted to known spectral shapes taken under conditions close to those in the actual experiment. Using this response function and subtracting a 56 μs half-life background due to neutron capture in the detector, the measured 0^? spectrum compares well with the allowed shape for the 0^?→0⁺ spectrum plus a small contribution from the allowed 0^?→1^? transition.     

Luminescence quantum efficiency of Mn2+ states in ZnS as studied by photoacoustic spectroscopy

Photoacoustic spectroscopy is employed to determine the luminescence quantum efficiency of Mn²⁺ in ZnS. Three spectra, photoacoustic spectrum, luminescence excitation spectrum and absorption spectrum, are compared. It is observed that the photoacoustic spectrum and the excitation spectrum behave complementarily. Radiative quantum efficiencies of the five excited states for Mn²⁺ have been determined.     

Energy spectrum of primary cosmic rays at energies of 2 × 10<Superscript>13</Superscript> to 5 × 10<Superscript>17</Superscript> eV,according to Tien Shan data

The primary cosmic ray energy spectrum at energies of 10¹⁵ to 5 × 10¹⁷ eV is presented using the results from observations by the Tien Shan HADRON array. The spectrum was obtained from the spectrum of showers according to the number of electrons using a new way of determining the parameter of spatial distribution function S of electrons. The energy spectrum can be extended to low energies up to 2 × 10¹³ eV using data from separate experiments at the former Tien Shan array. Conclusions are drawn regarding changes in the form of the spectrum and its chemical composition at energies over 10¹⁶ eV. The spectrum is compared to the results from the TUNKA installation.     

Quest for the 10He nucleus

The spectrum of ¹⁰He was studied by means of the ³H(⁸He, p)¹⁰He reaction at a laboratory energy of 25 MeV/A and small center-of-mass angles. Missing mass spectrum of ¹⁰He was derived from the obtained p-⁸He coincidence. A resolution of 0.7 MeV was achieved in this spectrum for the measured ¹⁰He energy. Most likely, a well isolated group of 10 events detected between 2 and 5 MeV and showing a maximum at about 3 MeV in the spectrum of the present work exhibits the ¹⁰He g.s. resonance.     

Derivation of muon spectrum at high energies from the recent JACEE primary cosmic-ray spectrum using Fermilab data on meson production

Summary The energy spectrum of sea level muons in the range (10²÷10⁴) GeV has been calculated from the latest directly measured JACEE primary spectrum using Fermilab results on pp→π^± X and pp→K^± X inclusive reactions. The conventional pion atmospheric diffusion equation after Bugaevet al. has been used in this analysis to account the flux of muons emerged from the multiple generation of mesons in air. The derived muon spectrum has been compared with the earlier magnetic spectrograph data of Durham and Kiel groups. The latest BAKSAN scintillator telescope data is well in agreement with the calculated integral spectrum originated from the meson decays in the range (1÷10⁴) GeV.     

NMR Studies of Hindered Rotation. The Diels-Alder Adduct of Phencyclone with p-Benzoquinone: Restricted Motion of Bridgehead Phenyls

The Diels-Alder adduct of phencyclone with p-benzoquinone has been examined by ¹H NMR at 300 MHz in CDCl₃ at ambient temperatures for evidence of hindered rotation of the unsubstituted bridgehead phenyl groups. The nearly first-order spectrum exhibits four approximate doublets and five approximate triplets in the aromatic region, of roughly equal intensity (ca. 2H). This is consistent with a slow-exchange limit (SEL) spectrum of the hindered phenyls. For rapidly rotating phenyls, the predicted fast-exchange limit (FEL) spectrum would have shown two 2H doublets and one 4H doublet, in addition to three 2H triplets and one 4H triplet, in the aryl region. Full ¹H assignments have been made, based on the two-dimensional ¹H-¹H homonuclear chemical shift correlation spectrum (COSY) and expected magnetic anisotropy effects.     

<Superscript>209</Superscript>Bi NMR spectrum of BiFeO<Subscript>3</Subscript> in the presence of spatial modulation of hyperfine fields

A complicated spin-echo spectrum was observed for ²⁰⁹Bi nuclei in a ferroelectric antiferromagnet BiFeO₃ in zero external field. This spectrum is the first example of nuclear quadrupole resonance of a system of diamagnetic atoms in a hyperfine magnetic field produced by the spatially modulated Fe³⁺ spin system and varying in orientation and magnitude. An attempt is undertaken to theoretically simulate the spectrum.     

CF3CDCl2分子红外多光子光热吸收谱

本文报道用铂丝光热吸收池作为探测器得到了CF₃CDCI₂的红外多光子吸收谱。并发现在线性吸收谱中944cm^-1处的吸收峰在多光子吸收谱中分裂为947cm^-1和927cm^-1两个吸收峰。这一现象与科里奥利力和非谐性引起的简正振动的耦合作用有关。这样,在用CF₃CDCI₂/CF₃CHCI₂体系分离氘同位素时,可以根据这一新结果选择更合适的激发波长。实验还发现在线性吸收谱中986cm^-1处的吸收峰在多光子吸收谱中出现约6cm^-2的红移。这种红移现象起源于分子振动能级的非谐性。 关键词：     

Raman spectrum of metallic layered compound NbSe2

Raman spectrum of layer-type compound NbSe₂ has been obtained at liquid nitrogen temperature. The frequencies of the Raman active modes E²_2g, A_1g and E¹_2g are measured to be 29.6 cm^?1, 230.9 cm^?1 and 238.3 cm^?1 respectively. The observed second order Raman spectrum of NbSe₂ is very different from the corresponding spectrum of MoS₂. These results show that the force constants of NbSe₂ are less anisotropic than those of MoS₂.     

Luminescence properties of Ce3+ doped gadolinium-calcium-silicaborate glass scintillator

In this work, the Ce³⁺ doped gadolinium-calcium-silicaborate glass scintillators of the composition ratio 25Gd₂O₃:10CaO:10SiO₂:(55−x)B₂O₃:xCeF₃, have been fabricated by using the melt-quenching technique. The doping concentration of the Ce³⁺ was varied from 0.05 mol% to 2.5 mol%. The 4f-5d transition of the Ce³⁺ allowed scintillation with a fast decay time. The absorption spectrum, X-ray induced emission spectrum, photo luminescence spectrum, laser luminescence spectrum and decay time of the scintillators were measured for studying the luminescence properties. From the X-ray induced emission spectrum result, we checked the trend between doping concentration and light yield. The laser induced luminescence spectrum was measured while changing the temperature from 300 K to 10 K. We also measured the decay time by using the laser excitation of the 0.15 mol% Ce³⁺ doped glass scintillator.     

Mössbauer spectra of gadolinite and aeschynite

The Mössbauer spectra of the Natural gadolinite and aeschynite at 297K and 81K were measured. The Mössbauer spectrum of the gadolinite consists of one Fe³⁺ doublet and two Fe²⁺ doublets, and the multiple Fe²⁺ doublets in the spectrum of the gadolinite were relating to the next nearest neighbour effect. The Mössbauer spectrum of the aeschynite is composed of one Fe³⁺ doublet and one Fe²⁺ doublet, and this result is in agreement with crystal structure determination.     

Sea Level Muon Spectrum Derived from the All Particle Primary Spectrum of GRIGOROV et al.

The all particle primary spectrum of GRIGOROV et al. surveyed by HILLAS has been fitted by a power law fit of the form I_{all particle}(>E) = 1.3 E^?1.65 (cm² s sr)^?1 where E is the energy in GeV/nucleus. Using our recently determined conversion factor for protonnuclei flux ratio of equal energies the primary proton spectrum has been calculated and the result agrees with the Goddard Space Flight Centre primary proton spectrum data satisfactorily. The primary nucleon spectrum has also been calculated and follows the form N_nucleons(E) dE = 2.664 E^?2.75 dE (cm² s sr GeV/nucleon)^?1. Using this primary nucleon spectrum as the source of hadrons and accelerator data for various inclusive reactions viz. used for the estimation of hadronic energy moments in the frame work of FEYNMAN- Scaling, the differential meson spectra have been estimated. The meson atmospheric diffusion equation after Bugaev et al. has been considered for the derivation of sea level muon spectrum. The magnetic spectrograph data of Allkofer et al., Ayre et al., Green et al., and MUTRON group are in accord with the calculated muon spectrum.     

Spectral properties of cones of approximately representable reduced density matrices

We introduce a definition of the approximate spectrum of an operator which is useful in reduced density matrix theory. With precise knowledge of $\text{D}$² (the cone of representable reduced 2-densities) our approximate spectrum of any Hermitian, symmetric, one-body operator, A, agrees with the usual spectrum of operators on Fock space. The virtue of our definition is that with only approximate knowledge of $\text{D}$² we can compute the approximate spectrum for A. The approximate spectrum turns out to be a sensitive tool in assessing the quality of cones of approximately representable reduced 2-densities. Using this notion, we are able to point out a dramatic failure of one cone of approximately representable reduced 2-densities often referred to in the literature. In addition we show how reduced density matrices for excited states of systems with two-body interactions can be computed, given $\text{D}$⁴ the cone of reduced 4-densities.     

Optical properties of BiTeI semiconductor with a strong Rashba spin-orbit interaction

We have modeled the 4f ¹-5d ¹ absorption spectrum of a LiYF₄:Ce³⁺ crystal at zero temperature using a microscopic model of the electron-phonon interaction and the real spectrum of LiYF₄ lattice vibrations. Effects caused by mixing of the wave functions of different states of the 5d ¹ excited configuration of the Ce³⁺ ion, which is induced by the electron-phonon interaction, are considered based on the calculations of the second-, third-, and fourth-order exact moments of curvature of the spectrum envelope. We have shown that the large value of the splitting between the maxima of the bands in the absorption spectrum that correspond to transitions to the third and fourth 5d ¹ levels is a result of the nonadiabatic interaction of 5d electrons with lattice vibrations.     

Cosmic ray energy spectrum from measurements of air showers

This review focuses on high-energy cosmic rays in the PeV energy range and above. Of particular interest is the knee of the spectrum around 3 PeV and the transition from cosmic rays of Galactic origin to particles from extra-galactic sources. Our goal is to establish a baseline spectrum from 1014 to 10^20 eV by combining the results of many measurements at different energies. In combination with measurements of the nuclear composition of the primaries, the shape of the energy spectrum places constraints on the number and spectra of sources that may contribute to the observed spectrum.     

Emission of Spectrum of BIF Molecule

The BiF molecule has a very extensive spectrum, from 5065 Å in the visible to 2250 Å in ultraviolet region. It was studied by Howell and Rochester¹ in emission and by Morgan² in absorption. A year later, Rochester³ again studied its emission spectrum, and recorded three new band systems.     

基于LabVIEW的252Cf中子源频谱分析

 从²⁵²Cf中子源频谱测量系统的基本原理出发,针对中子脉冲序列本身“0,1”数据结构的特点,设计了自、互相关快速算法。采用LabVIEW多核处理器、多线程编程技术构建了基于LabVIEW的²⁵²Cf中子源频谱分析系统,不仅获得了自、互相关的快速计算结果,而且获得了自、互功率谱及谱密度比。研究结果表明：基于LabVIEW分析工具,既提升了自、互相关算法代码25%~35%的执行效率,又验证了LabVIEW用于进行频谱系统分析的可行性。