多媒体辅助教学在植物生物学中的应用

多媒体辅助教学作为现代化的教学手段对提高教学效果有积极的作用.文章从多媒体辅助教学的优势、多媒体课件的制作以及多媒体辅助教学的实施三方面论述了多媒体辅助教学在植物生物学中的应用。     

椭球等高准对角矩阵Beta、F分布

在左球准对角矩阵分布、球对称准对角矩阵分布的基础上研究了准对角矩阵Beta分布、准对角矩阵F分布,给出了分布的密度函数和矩,进一步得到了相应逆矩阵变量分布的密度函数和矩.     

Engineered polycaprolactone – magnesium hybrid biodegradable porous scaffold for bone tissue engineering

In this paper, we describe the fabrication of a new biodegradable porous scaffold composed of polycaprolactone(PCL) and magnesium(Mg)micro-particles. The compressive modulus of PCL porous scaffold was increased to at least 150% by incorporating 29% Mg particles with the porosity of 74% using Micro-CT analysis. Surprisingly, the compressive modulus of this scaffold was further increased to at least 236% when the silane-coupled Mg particles were added. In terms of cell viability, the scaffold modified with Mg particles significantly convinced the attachment and growth of osteoblasts as compared with the pure PCL scaffold. In addition, the hybrid scaffold was able to attract the formation of apatite layer over its surface after 7 days of immersion in normal culture medium, whereas it was not observed on the pure PCL scaffold. This in vitro result indicated the enhanced bioactivity of the modified scaffold. Moreover, enhanced bone forming ability was also observed in the rat model after 3 months of implantation. Though bony in-growth was found in all the implanted scaffolds. High volume of new bone formation could be found in the Mg/PCL hybrid scaffolds when compared to the pure PCL scaffold. Both pure PCL and Mg/PCL hybrid scaffolds were degraded after 3 months. However, no tissue inflammation was observed. In conclusion, these promising results suggested that the incorporation of Mg micro-particles into PCL porous scaffold could significantly enhance its mechanical and biological properties. This modified porous bio-scaffold may potentially apply in the surgical management of large bone defect fixation.     

航天器项目软件计划管理

软件产品同硬件产品一样是航天器研制过程中必不可少的一个配置项,因此软件计划管理是航天器项目管理中一个重要的组成部分,是确保航天项目中软件产品按计划交付所必须的管理过程,在型号研制过程中发挥着关键的作用。     

基于神经网络的变换域通信系统接收技术

提出了一种不须要估计本地基函数的变换域通信系统接收机接收方法.详细分析了接收机的接收原理,以相关解调信号能量最大化为目标构建了接收机最优化接收模型,通过对模型求解得到了接收数据自协方差矩阵的最大特征值向量,此向量可作为接收端基函数实现最佳接收,从而引入基于Hebbian学习训练的神经网络完成最大特征值向量的自适应估计与数据接收.仿真结果表明:当算法收敛时,作为基函数估计的网络连接强度矢量与发送端基函数基本一致,并且当发送端改变基函数时,算法依然能够实现准确跟踪.系统的接收性能与收发两端基函数一致条件下的接收性能基本一致,当算法迭代次数为300,误码率为1×10-4时,系统的信噪比损失可小于1dB.     

纯电动汽车制动能量回收评价与试验方法研究

为评价纯电动轿车制动能量回收效果,在分析纯电动汽车能量流的基础上,提出采用电机回收的能量与制动过程中的总能量的比值,即制动能量回收率作为纯电动汽车制动能量回收评价指标.分析已有试验方法,选取在转鼓试验台上进行NEDC(New European Driving Cycle)循环工况法为纯电动汽车制动能量回收试验方法.选择三款纯电动汽车,根据所述试验方法进行试验,得到了三种车型的制动能量回收率.试验表明:所提出的试验方法简单,评价指标合理,有利于纯电动汽车的制动能量回收的评价.     

MnF2吸收光谱的理论解释

通过对Ｍｎ＾２＋的实验值进行半经验的拟合,得到了它的３ｄ电子波函数,并利用晶体场理论中的点电荷模型,计算也ＭｎＦ２晶体的吸收光谱,计算结果与实验值吻合很好。     

超低碳冷轧薄板单向拉伸过程变形机理

通过对超低碳ＩＦ钢冷轧薄钢板拉伸过程中不同变形程度的测试与扫描电镜的观察,研究了其表面形貌及组织的变化规律．探讨了超低碳钢韧性断裂中内部孔洞形成机理,并指出超低碳钢中的微孔洞不是主要由夹杂物或第二相粒子产生,而是因为位错的滑移、集聚,在原有损伤处形成．     

染料脱色菌群的分离及对红色偶氮染料的脱色研究

从印染厂废水池的污泥中分离筛选到一组染料脱色菌群。研究了该脱色菌群在不同温度、pH 值、培养时间、需氧与否和是否含有机物的条件下对红色偶氮染料的脱色情况。试验结果表明,脱色菌群对外界条件无严格要求,适应范围广。但在pH 为9.0 ,温度为30 ℃,培养时间为72h,厌氧和含有机物的条件下对染料有较好的脱色效果