分子铁磁体的表征

分子铁磁体的研究是自由界向化学家挑战的一个热点课题。文章主要介绍几种常用的分子基铁磁性的表征方法。     

电磁感应定律两种不同表述形式的相互比较

通过对电磁感应定律两种不同表述形式的比较,揭示出各自的特点和本质上的相互联系。     

Sr5s~(21)S_0-5s4d~1D_2单光子电四极矩E2跃迁及其缓冲气压对侧向荧光光谱影响的研究

用染料激光来激发Sr原子 ,首次在实验上发现较强的Sr 5s2 1 S0 — 5s4d1 D2 单光子电四极矩E2共振跃迁离化信号 ,并对缓冲气压对侧向荧光光谱的影响进行了判断与分析。     

磁刺激促进骨折愈合及对血液生化参数的影响(英文)

对１２０例新鲜骨折患者进行了磁刺激对骨折愈合和多种血液生化参数影响的试验研究,分析了磁刺激促进骨折愈合的作用机理．对比试验结果表明：磁刺激可促进钙盐沉着,加强人体的钙磷代谢,从而加速骨折的愈合过程．     

Transient analysis of steam generator in PWR nuclear power plant

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松下WE—6600型录音机的故障分析与处理

论述松下WE－6600型录音机常见的几种故障产生的原因以及排除故障的方法。     

必须重视核能发电的安全和环境风险

通常许多专家和学者把核电(核裂变发电)作为低碳发展的首选能源,其理由在于核能是清洁、安全、便宜的能源。文章认为,由于核废料处置的困难,核安全的不确定性,核能并不是想象中的清洁安全便宜的能源。我们必须从切尔诺贝利和日本福岛核事故中吸取教训,重新认识核能发电的安全和环境风险。由于我国的核电技术相对薄弱,铀资源相对不足,核电产业必须科学规划,坚持安全第一,充分考虑核事故对经济、社会和环境的影响。     

行波磁场净化液态金属时磁感应强度分布对净化效果的影响

The distribution of the magnetic flux density in the magnetic field generator which provided travelling magnetic field was determined. The experiments using liquid gallium and aluminum - silicon alloy to observe the turbulent flow or remove inclusions were performed to obtain the basic principles how the distribution of the magnetic flux density took effect on removing inclusions from molten metal by electromagnetic field. The suitable area in the field for purifying metal was suggested.     

Co13O8—metalloxocubes: a new class of perovskite-like neutral clusters with cubic aromaticity

Exploring stable clusters to understand structural evolution from atoms to macroscopic matter and to construct new materials is interesting yet challenging in chemistry. Utilizing our newly developed deep-ultraviolet laser ionization mass spectrometry technique, here we observe the reactions of neutral cobalt clusters with oxygen and find a very stable cluster species of Co₁₃O₈ that dominates the mass distribution in the presence of a large flow rate of oxygen gas. The results of global-minimum structural search reveal a unique cubic structure and distinctive stability of the neutral Co₁₃O₈ cluster that forms a new class of metal oxides that we named as ‘metalloxocubes’. Thermodynamics and kinetics calculations illustrate the structural evolution from icosahedral Co₁₃ to the metalloxocube Co₁₃O₈ with decreased energy, enhanced stability and aromaticity. This class of neutral oxygen-passivated metal clusters may be an ideal candidate for genetic materials because of the cubic nature of the building blocks and the stability due to cubic aromaticity.     

磁共振成像技术及其应用

磁共振成像技术依据原子核能级跃迁释放能量在物质不同结构环境中不同的衰减,通过外加梯度磁场检测所发射的电磁波,获得构成物体的原子核种类和位置,从而绘制出物体内部的结构图像．近年来,随着快速变化的梯度磁场的应用,核磁共振成像技术不仅在医学,而且在其他科研领域都得到了广泛的应用．