锂铁氧体纳米晶的磁性能研究

我们用ＰＥＧ凝胶法合成出的ＬｉＦｅ＿５Ｏ＿３纳米晶，用ＸＲＤ和ＴＥＭ观测其粒径和形貌。用振动样品磁强计考察其比饱和磁化强度σ＿ｓ，随粒径口变化，得到样品的σ＿ｓ随Ｄ的减小而下降。     

Acetylcholinesterase enhances neurite growth and synapse development through alternative contributions of its hydrolytic capacity, core protein, and variable C termini

Accumulated indirect evidence suggests nerve growth-promoting activities for acetylcholinesterase (AChE). To determine unequivocally whether such activities exist, whether they are related to the capacities of this enzyme to hydrolyze acetylcholine and enhance synapse development, and whether they are associated with alternative splicing variants of AChEmRNA, we used four recombinant human AChEDNA vectors. When Xenopus laevis embryos were injected with a vector expressing the synapse-characteristic human AChE-E6, which contains the exon 6-encoded C terminus, cultured spinal neurons expressing this enzyme grew threefold faster than co-cultured control neurons. Similar enhancement occurred in neurons expressing an insertion-inactivated human AChE-E6-IN protein, containing the same C terminus, and displaying indistinguishable immunochemical and electrophoretic migration properties from AChE-E6, but incapable of hydrolyzing acetylcholine. In contrast, the nonsynaptic secretory human AChE-I4, which contains the pseudointron 4-derived C terminus, did not affect neurite growth. Moreover, no growth promotion occurred in neurons expressing the catalytically active C-terminally truncated human AChE-E4, demonstrating a dominant role for the E6-derived C terminus in neurite extension. Also, AChE-E6 was the only active enzyme variant to be associated with Xenopus membranes. However, postsynaptic length measurements demonstrated that both AChE-E6 and AChE-E4 enhanced the development of neuromuscular junctions in vivo, unlike the catalytically inert AChE-E6-IN and the nonsynaptic AChE-I4. These findings demonstrate an evolutionarily conserved synaptogenic activity for AChE that depends on its hydrolytic capacity but not on its membrane association. Moreover, this synaptogenic effect differs from the growth-promoting activity of AChE, which is unrelated to its hydrolytic capacity yet depends on its exon 6-mediated membrane association.     

广东省伴生放射性矿资源利用过程辐射水平调查

为加强伴生放射性矿物资源开发利过程中放射性环境管理 ,防治放射性污染 ,对广东省几个大型伴生矿(包括稀土矿、钽铌矿和铅锌矿 )资源利用 (开采、冶炼、加工 )过程中天然放射性核素的污染现状进行了调查。调查结果表明 :稀土矿中独居石 ,天然放射性核素含量最高 ,2 3 8U、2 3 2 Th、2 2 6Ra的含量分别为 3.5 1× 1 0 4、1 .74× 1 0 5、4 .8×1 0 4Bq/kg,其冶炼废渣中核素的含量分别为 5 .1 0× 1 0 5、6 .38× 1 0 6、1 .5 2× 1 0 6Bq/kg。稀土选冶厂周围陆地环境 γ射线的空气吸收剂量率比一般地区的高。     

连续小波变换在多元函数空问中的应用

使用连续小波变换讨论了某些偏微分方程和相应的积分方程之间的关系．使用连续小波变换能够将这些偏微分方程变换成相应的积分方程，这些偏微分方程与相应的积分方程不仅在弱收敛意义下是等价的，而且在范数收敛意义下也是等价的．     

无线Internet接入技术及其发展现状

无线Internet接入是无线通信技术Internet结合的产物，本首先介绍了在线Internet接入的优势，然后详细列举了目前主要的无线Internet接入技术，并给出了应用特点。最后讨论了无线Internet接入的发展现状和存在的主要问题。     

On the interaction impedance of the coupled cavity structure

The formula and program for calculating the total and negative first harmonic interaction impedance from the data of “large perturbation measurement” are given. This program is a part of the programs for CCTWT design.     

基于一种特定混沌映射的跳频序列

使用一种简单的分段线性映射构造混沌跳频序列。用于跳频通信中取代传统的伪随机序列（PN序列），分析了此混沌序列的周期性。平衡性，汉明相关特性和线性间隔，最后给出了混沌序列的神经网络实现。仿真和实验结果表明，此序列具有较好的统计特性。应用于跳频多址通信中，可获得较好的抗干扰。抗截获能力。     

新型高温高密度W/O乳化钻井液的研制

研制了油包水乳化钻井液的基本配方，评价了其抑制性，热稳定性，以及抗水侵污能力，抗钻屑侵污能力，抗水泥侵污能力。现场应用表明，该体系具有较强的抑制作用，能很好地稳定井壁，保护油气层。     

地球物理与中国的可持续发展

在20世纪中国的发展历程中,地球物理在资源探查、环境保护和减轻自然灾害服务等诸多方面发挥了举足轻重的作用。21世纪,中国走可持续发展之路已成为必然选择。随着可持续发展思想及内涵的逐渐丰富,地球物理必将为中国的可持续发展起到更大作用。     

雷达检测技术在建设工程无损检测中的应用

简要介绍了雷达检测的原理 ,并通过工程实例 ,介绍了雷达检测技术在建设工程中的应用。