硅的

Systematical variations of silica contents and silicon isotope compo- sitions are observed from their roots to stem to leaves, which provide us reliable evidences for studying the mechanisms of adsorption, transpor- tation and precipitation of silicon in plants, as well as the role of plants in silicon biogeochemical cycle.

由根往茎叶，硅的含量与同位素组成呈规律性变化。为研究植物中硅的吸收、搬运与沉淀机制，探讨植物在硅的生物地球化学循环中的作用提供依据。

In this thesis, on the basis of experimental and theoretical research, we study the factors that lead to low electroluminescence efficiency of PS and the stability of PL in PS.

在本论文中，我们通过理论和实验研究，对造成多孔硅电致发光效率低的原因以及多孔硅的发光稳定性问题进行了一些探索。

Combining ion exchange process and silicon hydrolyze process Silicon dioxide mother nuclide with a specific particle size was prepared from sodium silicate through the dropwise technique , then the large particle size , high concentration and stable silica sol was prepared . The stability of silica sol also can be improved by enwrap .

和"单质硅一步溶解法"相结合的方法，用离子交换法制备晶种，并采用滴加工艺制备一定粒径大小的二氧化硅作为母核，在催化剂和分散剂共同作用下水解单质硅的方法使二氧化硅母核颗粒进一步增长成大粒径的二氧化硅颗粒，并另外还采用水溶性高分子对纳米SiO_2粒子进行"原位表面包覆"提高其稳定性，制备了大粒径，高浓度，稳定的纳米硅溶胶。

The current theory and application of Al-Si alloy mainly focus on the study of hypoeutectic and eutectic, therefore we systematically analyzed the modification process of hypereutectic Al-Si alloy based on the methods and results of predecessors. Several factors including the modification temperature, the content of modifier, the available holding time, the times of repeat melting , the casting temperature and the speed for cooling have been studied in order to understand its effects to the composition, function and performances of primary silicon and eutectic silicon.

中文摘要本文针对目前Al-Si合金相关应用和理论的研究多集中于亚共晶和共晶合金的情况，在前人的研究成果和研究方法的基础上，对过共晶Al-Si合金变质处理进行了较为系统的分析，研究了变质剂的成分配比、变质温度、变质剂的加入量、变质后的静置时间、浇注温度及冷却速度等因素对过共晶铝硅合金中初晶硅和共晶硅的大小、形状、数量和分布的影响。

The current theory and application of Al-Si alloy mainly focus on the study of hypoeutectic and eutectic, therefore we systematically analyzed the modification process of hypereutectic Al-Si alloy based on the methods and results of predecessors. Several factors including the modification temperature, the content of modifier, the available holding time, the times of repeat melting , the casting temperature and the speed for cooling have been studied in order to understand its effects to the composition, function and performances of primary silicon and eutectic silicon.

本文针对目前Al-Si合金相关应用和理论的研究多集中于亚共晶和共晶合金的情况，在前人的研究成果和研究方法的基础上，对过共晶Al-Si合金变质处理进行了较为系统的分析，研究了变质剂的成分配比、变质温度、变质剂的加入量、变质后的静置时间、浇注温度及冷却速度等因素对过共晶铝硅合金中初晶硅和共晶硅的大小、形状、数量和分布的影响。

Based on above observations, it can be inferred that: a Monosilicic acid is the major silicon-bearing component taken up by roots of rice and bamboo; b Passive uptake of silicon is important for these plants; c Evapo-rate-transpiration may be the major mechanism for the transportation and precipitation of silicon in these plants.

研究得出：1水稻与竹子由外界吸收的含硅化合物主要为正硅酸；2被动吸收是其吸收硅的重要形式；3蒸发作用是硅在这些植物中迁移和沉淀的主要机制。

Silicofluoride acid radical of the mother liquor will be transformed into sodium silicofluoride if excess sodium chloride was added,and the mother liquor was refined.The refined hydrofluoric acid and various aluminum can compose the by-product-cryolite,which can improve the collection rate of fluorin,aluminum and silicon.

其关键技术为氯化钠脱硅：投入过量氯化钠，使母液中氟硅酸根转化成副产品氟硅酸钠，母液被精制；再加入精制氢氟酸与各形态铝合成冰晶石副产品，从而有效地提高了氟、铝和硅的收率。

Studies on combining optical absorption and PL from free-standing PS films with porosities in a range of 41% to 94% have been performed.

三、详细研究了在多种硅衬底上制备的多孔硅自支撑膜的光吸收和光致发光性质，并在很宽的多孔度范围内(58-94％)对多孔硅的光吸收和光致发光性质进行了对比。

The standard sample of high pure silicon tetrachloride with certified value of 99.99 % was analyzed. The obtained average determination result was 99.857% after normalization treatment. The relative standard deviation was 0.03%.

对认定值为99.99%高纯四氯化硅标准样品分析，归一化法定量，得到该样品中四氯化硅的测定平均值为99.857%，相对标准偏差为0.03%。

The luminescence mechanism was studied and we considered that photo-excitation occurs at inside of Si nanoparticles, and then the photo-generated carriers relax to the surface and radiatively recombine on the surface states.

我们对多孔硅的发光机理进行了分析研究，认为光激发发生在纳米硅颗粒中，光生载流子弛豫到颗粒表面，在表面氧化层中表面态上辐射复合而发光。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。