小扭口藓(Barbula indica)芽胞发育特征的实验研究

在光照培养箱中人工对照培养小扭口藓(Barbulaindica(Hook. )Spreng)的芽胞,显微镜下观察并记录其发育成配子体的全过程。结果表明:小扭口藓芽胞在3 ~4d即可萌发; 10d左右开始分化出绿丝体、轴丝体及假根; 18d,轴丝体上的侧枝顶端细胞以分生缢割的方式产生单细胞或多细胞芽胞; 40d,轴丝体上开始出现配子体原始细胞;之后,配子体原始细胞发育成桑椹状的幼小配子体。还对芽胞形态发育、生理生态及配子体发生过程的特点进行了分析和讨论。，CN 23-1480/

福建漳州龙海铁染高岭土磁选尾矿的矿物特征分析

对福建龙海红褐色铁染高岭土磁选尾矿进行了提纯,分离出强磁性含铁矿物,并对其进行了X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、穆斯堡尔谱和磁性测试等分析.研究结果表明:该尾矿所含的强磁性含铁氧化物并非文献报道的磁铁矿(Fe3O4),而是磁赤铁矿(γ-Fe2O3).穆斯堡尔谱分析未检测出样品中存在二价铁,结合XRD及磁性分析,表明磁选尾矿的磁性主要由磁赤铁矿引起.磁赤铁矿在福建省境内尚属首次发现.综合考虑该矿区其他伴生矿物的矿物成分、形貌等特征,及其所处的亚热带温暖潮湿性气候环境,确定该矿区具备形成磁赤铁矿的客观地质条件.通过对矿区的高岭土矿物形貌的大量分析,观察到罕见的高岭土形貌——卷曲型双壁或多壁微米管

对流扩散方程三角形有限元解的一致估计

利用三角形线性元的积分恒等式,给出了二维非定常对流扩散方程的半离散有限元解和真解的一致最优误差估计,即误差与ε无关,而仅与右端f和初值u_0有关

Redistribution of iron during directional solidification of metallurgical-grade silicon at low growth rate

研究冶金级硅低速定向凝固过程中杂质铁的再分布。采用ICP-MS检测铁的浓度,绘制铁在固相、液相、晶界和晶体生长方向上的浓度示意图。铁浓度在固、液相中具有明显差异。依据质量守恒定理,计算得出溶质边界层约为4 mm,铁的有效分凝系数约为2.98×10~(-4)。在低速凝固条件下,铁容易偏析聚集在晶界。在生长方向上,由于低速凝固,铁浓度在硅锭86%高度以下几乎恒定,不完全符合Scheil方程规律。讨论了对流对铁再分布的影响,对流"死区"对铁再分布具有重要影响。Redistribution of iron during directional solidification of metallurgical-grade silicon(MG-Si) was conducted at low growth rate. Concentrations of iron were examined by ICP-MS and figured in solid and liquid phases, at grain boundary and in growth direction. Concentrations are significantly different between solid and liquid phases. The thickness of the solute boundary layer is about 4 mm verified by mass balance law, and the effective distribution coefficient is 2.98×10~(-4). Iron element easily segregates at grain boundary at low growth rate. In growth direction, concentrations are almost constant until 86% ingot height, and they do not meet the Scheil equation completely, which is caused by the low growth rate. The effect of convection on the redistribution of iron was discussed in detail. Especially, the "dead zone" of convection plays an important role in the iron redistribution.Projects(51334004,51204143)supported by the National Natural Science Foundation of China;; Project(2006L2003)supported by the Scientific Technological Innovation Platform of Fujian Province,Chin