Uniform Lanthanide Orthoborates LnBO(3) (Ln = Gd, Nd, Sm, Eu, Tb, and Dy) Microplates: General Synthesis and Luminescence Properties

A variety of uniform lanthanide orthoborates LnBO(3) (Ln = Gd, Nd, Sm, Eu, Tb, and Dy) microplates have been successfully prepared by a general and facile conversion method. One-dimensional (ID) lanthanide hydroxides were first prepared through a simple hydrothermal process. Subsequently, uniform LnBO(3) microplates were synthesized at the expense of the ID precursors during a hydrothermal conversion process. The whole process in this method was carried out in aqueous condition without the use of any organic solvents, surfactant, or catalyst. The as-obtained rare earth ions doped GdBO3 and TbBO3 microplates show strong light emissions with different colors coming from different activator ions under ultraviolet excitation or low-voltage electron beam excitation, which might find potential applications in fields such as light phosphor powders and advanced flat panel display devices.

未来气候变化对黄土高原黑河流域水资源的影响

气候变化对黄土高原的水资源有重要影响,对其影响进行评估可以为区域发展提供重要的决策依据。基于分布式水文模型SWAT和4种全球环流模式的各3种排放情景,评估了2010～2039年黄土高塬沟壑区黑河流域水资源对气候变化的潜在响应。结果表明,黑河流域2010～2039年的年均降水变化-2.3%～7.8%,年均最高和最低温度分别升高0.7～2.2℃和1.2～2.8℃,年均径流量变化-19.8%～37.0%,1.2m剖面年均土壤水分含量变化-5.5%～17.2%,年均蒸散量普遍增长0.1%～5.9%;水文气象变量变化趋势复杂,但T检验表明年降水、径流、土壤水分和蒸散增长的概率较大。对于季节变化,降水可能在12～7月份和9月份增长,8月份和10～11月份减少;径流在4～7月份和9～10月份增加,11～3月份和8月份减少;土壤水分在各月都增长;蒸散11～6月份普遍增长,7～10月份减少的可能性较大。未来气候将发生显著变化并对水资源有重要影响,需采取必要的措施来减缓其不利影响。

General SU(2)(L) x SU(2)(R) x U(1)(EM) sigma model with external sources, dynamical breaking and spontaneous vacuum symmetry breaking

We give a general SU(2)(L) x SU(2)(R) x U(1)(EM) sigma model with external sources, dynamical breaking and spontaneous vacuum symmetry breaking, and present the general formulation of the model. It is found that sigma and pi(0) without electric charges have electromagnetic interaction effects coming front the internal structures. A general Lorentz transformation relative to external sources J(gauge) - (J(A mu) J(A mu)(kappa)) derived, using the general Lorentz transformation and the four-dimensional current of nuclear matter of the ground si ate with J(gauge) = 0, we give the four-dimensional general relations between the different currents of nuclear matter systems with J(gauge) not equal 0 and those with J(gauge) = 0. The relation of the density's coupling with external magnetic field is derived, which conforms well to dense nuclear matter in a strong magnetic field. We show different condensed effects in strong interaction about fermions and antifermions, and give the concrete scalar and pseudoscalar condensed expressions of sigma(0) and pi(0) bosons. About different dynamical breaking and spontaneous vacuum symmetry breaking, the concrete expressions of different mass spectra are obtained in field theory. This paper acquires the running spontaneous vacuum breaking value sigma'(0), and obtains the spontaneous vacuum breaking in tenus of the running sigma'(0), which make nucleon, sigma, and pi particles gain effective masses. We achieve both the effect of external sources and nonvanishing value of the condensed scalar and pseudoscalar paticles. It is deduced that the masses of nucleons, sigma and pi generally depend on different external sources.