中药中微量元素作用

中药中微量元素作用王长春，赵志国（江苏省射阳县皮肤病防治所，射阳２２４３００）近年来，由于生物地球化学、医学地理学等学科的进展，逐渐揭示了微量元素与人类生命和健康的关系。微量元素在防治心血管系统疾病、某些地方病、癌症及抗衰老等方面的实际应用价值，已经...     

Direct acceleration of electrons using two crossed Laguerre--Gaussian laser beams in vacuum

The basic physical characteristics of electrons accelerated by two linearly polarized and circularly symmetric crossed Laguerre--Gaussian (LG) laser beams with equal frequency and amplitude in vacuum are studied in detail. The condition, under which electrons can be accelerated effectively, and the energy gain are discussed.     

Vectorial Hermite--Laguerre--Gaussian beams beyond the paraxial approximation

Starting from the vectorial Rayleigh--Sommerfeld integrals, the free-space propagation expressions for vectorial Hermite--Laguerre--Gaussian (HLG) beams beyond the paraxial approximation are derived. The far-field expressions and the scalar paraxial results are given as special cases of our general expressions. The intensity distributions of vectorial nonparaxial HLG beams are studied and illustrated with numerical examples.     

Deterministically distinguishing a remote Bell state

It has been proven that, with a single copy provided, the four Bell states cannot be distinguished by local operations and classical communications (LOCC). Traditionally, a Bell basis projective measurement is needed to distinguish the four Bell states, which is usually carried out with a local interference between two particles. This paper presents an interesting protocol that allows two remote parties to distinguish four Bell states deterministically. We prove that our protocol of distinguishing remote Bell states is beyond LOCC.     

Electron acceleration by two crossed Bessel--Gaussian beams in vacuum

The direct acceleration of electrons by using two linearly polarized crossed Bessel--Gaussian (BG) beams with equal frequency and amplitude in vacuum is proposed and studied. It is shown that two linearly polarized BG beams of the same order (0 or 1) with a \textit{\pi }-rad phase difference have a resultant non-zero longitudinal electric field on the z-axis and can be used, in principle, to accelerate electrons.     

非傍轴双曲余弦-高斯脉冲电磁光束远场特性

利用矢量瑞利-索末菲衍射积分公式,推导出了非傍轴部分空间相干部分光谱相干双曲余弦-高斯(ChG)脉冲电磁光束在自由空间传输时交叉谱密度矩阵的远场解析公式,并用来表示脉冲电磁光束的光谱密度(光强)和偏振度。结果表明,对非傍轴远场部分空间相干部分光谱相干ChG脉冲电磁光束,其非傍轴性主要由参数f, f决定,而离心参数、脉冲宽度和时间相干长度影响其非傍轴行为。非傍轴部分空间相干部分光谱相干高斯-谢尔模型脉冲电磁光束的远场传输可作为特例处理。