Effect of dielectronic recombination excitation in the solar x-ray lines of calcium-ions

The effect of dielectronic recombination as an excitation process in the intensity of solar x-ray lines of calcium ions is investigated. It is found that x-ray line intensities are enhanced by 15% to 88% with the inclusion of dielectronic recombination as an excitation mechanism.     

High-resolution spectroscopic imaging of the Sun with a universal birefringent filter and a Fabry-Perot Interferometer

Summary We describe an optical device consisting of a Universal Birefringent Filter and a Fabry-Perot interferometer used in tandem to obtain monochromatic images of the Sun in the visible spectrum (between 4200 and 7000 ?). The spectral resolving power is about 300000 and the wavelength stability might reach 0.02 m? at 5000 ? (≈1.2 m/s) with an integration time of 1 s. The image is recorded by a CCD camera based on a Thomson THX31159 device with 512×512 square pixels 19 μm in size. A prototype of this instrument was tested at the G. B. Donati Solar Tower of the Arcetri Astrophysical Observatory by obtaining, at fixed time intervals, several series of full disk monochromatic images of the Sun at different wavelengths inside the Fe I 5905.7 ? photospheric line. In this paper we describe the instrument and its characteristics and we give an cccount of the preliminary results obtained by measuring the global velocity field on the solar photosphere. These results show that the instrument is well suited for global oscillation measurements. Paper presented at the V Cosmic Physics National Conference, S. Miniato, November 27–30, 1990.     

Improvement of amorphous silicon n-i-p solar cells by incorporating double-layer hydrogenated nanocrystalline silicon structure

We develop a double-layer p-type hydrogenated nanocrystalline silicon (p-nc-Si:H) structure consisting of a low hydrogen diluted i/p buffer layer and a high hydrogen diluted p-layer to improve the hydrogenated amorphous silicon (a-Si:H) n-i-p solar cells. The electrical, optical and structural properties of p-nc-Si:H films with different hydrogen dilution ratio (R_H) are investigated. High conductivity, low activation energy and wide band gap are achieved for the thin films. Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM) analyses indicate that the thin films contain nanocrystallites with grain size around 3-5 nm embedded in the amorphous silicon matrix. By inserting a p-nc-Si:H buffer layer at the i/p interface, the overall performance of the solar cell is improved significantly compared to the bufferless cell. The improvement is correlated with the reduction of the density of defect states at the i/p interface.     

具有整体代对称性的左右对称模型中的中微子质量

本文基于具有整体U(1)代对称性的SU(2)_L×SU(2)_R×U(1)模型推导了轻子的味混合矩阵,对中微子的质量问题进行了研究.在本文的模型中,产生轻子Dirac质量的汤川耦合拉格朗日密度具有整体U(1)代对称性,所以,模型中的带电轻子质量矩阵和中微子Dirac质量矩阵是Fritzsch形式的.但是,中微子除了具有Dirac质量,一般还具有Majorana质量,在这种一般情况下, 关键词： 中微子质量 轻子味混合矩阵 左右对称模型 代对称性     

利用地磁场综合模型CM4分析中国大陆地区地磁场变化

第四代地磁场综合模型CM4是迄今为止将地磁场的内源场和外源场分离得最为彻底的数学模型.利用该模型结合Taylor多项式模型,基于1960—2000年期间中国大陆地区的实测数据,计算并分析了以10a为间隔的内源场和外源场的变化情况,通过将1960—1990年的所有磁异常点归算至2000年以分析地壳磁异常场的总体分布趋势.结果显示:地磁北向分量X的内源场强度总体呈逐年减弱的趋势,从1960年到2000年共下降了约750nT,外源场强度总体呈先增强后减弱的趋势,共下降了约32nT;地磁东向分量Y的内源场强度总体呈先减弱后增强的趋势,1960—2000年期间共上升了约40nT,外源场强度总体呈先减弱后增强再减弱的趋势,共上升了约3.8nT;地磁垂直分量Z的内源场变化趋势与Y分量类似,共上升了约600nT,外源场总体呈先减弱后增强的趋势,共上升了约4.6nT.对于地壳磁异常场,X分量、Z分量、地磁总强度F和地磁水平分量H在中国大陆地区都为负异常分布,X分量和H分量的负异常强度随经度增加而减弱,Z分量和F分量则相反;Y分量和磁偏角D的分布较为类似,在中国的中西部大部分地区为正异常,强度随经度增加而减弱,磁倾角I主要以负异常为主,负异常强度随经度增加而增强.     

Bremsstrahlung neutrino energy loss for ~(24)Mg, ~(28)Si, ~(32)S, ~(40)Ca, ~(56)Fe in strong electron screening

Based on WeinbergoSalam theory the bremsstrahlung neutrino energy loss for nuclei ~(24)Mg, ~(28)Si, ~(32)S, ~(40)Ca and ~(56)Fe are investigated in strong electron screening. Our results are compared with those of Dicus' and show that the latter are higher by 2 orders of magnitude in the density-temperature region of 10~8 g/cm~3 ≤ρ/μ_e≤10~(11) g/cm~3 and 2.5 ≤ T_9 ≤4.5. On the other hand, the factor C shows that the maximum differences are 99.16%, 99.13%, 99.12%, 99.055%, 99.040% corresponding to the nuclei ~(24)Mg, ~(28)Si, ~(32)S, ~(40)Ca and ~(56)Fe.     

Can a non-unitary effect be prominent In neutrino oscillation measurements?

Subject to neutrino experiments, the mixing matrix of ordinary neutrinos can still have small vi-olation from unitarity. We introduce a quasi-unitary matrix to interpret this violation and propose a natural scheme to parameterize it. A quasi-unitary factor △QF is defined to be measured in neutrino oscillation exper-iments and the numerical results show that the improvement in experimental precision may help us figure out the secret of neutrino mixing.     

Causality principle and nuclear dispersion anomaly in the elastic scattering for α+12C system

The optical model analysis of the alpha particle elastic scattering on a carbon target was performed on the basis of the dispersion relation between the real and imaginary parts of the calculated volume integrals. A nuclear dispersion anomaly in an α+12C system was observed and interpreted clearly.     

Parity anomaly in a \mathcal{P}\mathcal{T}-symmetric quartic Hamiltonian

In this paper, two independent methods are used to show that the non-Hermitian -symmetric wrong-sign quartic Hamiltonian H = (1/2m)p ² − gx ⁴ is exactly equivalent to the conventional Hermitian Hamiltonian . First, this equivalence is demonstrated by using elementary differential-equation techniques and second, it is demonstrated by using functional-integration methods. As the linear term in the Hermitian Hamiltonian is proportional to ℏ, this term is anomalous; that is, the linear term in the potential has no classical analog. The anomaly is a consequence of the broken parity symmetry of the original non-Hermitian -symmetric Hamiltonian. The anomaly term in remains unchanged if an x ² term is introduced into H. When such a quadratic term is present in H, this Hamiltonian possesses bound states. The corresponding bound states in are a direct physical measure of the anomaly. If there were no anomaly term, there would be no bound states.