基于DDS技术的FM信号发生器的设计及其FPGA实现

以FPGA为主要硬件,采用直接数字频率合成技术结合嵌入式锁相环,开发出了一种具有数字调制功能的FM信号发生器,并在自行研制的ALTERA Cyclone实验板上得到实现.经调试,该信号发生器的频率分辨率为0.596 HZ,最高输出载波频率达到10 MHz,同时具有输出相位连续,抗干扰能力强等优点.     

福建省生态功能小区分类及特征说明

福建省是一个山地丘陵多，生态环境区域分异特征突出，景观十分破碎复杂的省份。福建省生态功能区划工作一直走在全国前列，在省级生态功能区划划分三级区划单元的基础上，又率先开展了县级生态功能区划工作，进一步细分出第四级区划单元生态功能小区。本文介绍了划分生态功能小区的意义及划分方法，根据生态环境要素的地域分异特征、生态环境敏感性和生态服务功能的空间分布规律将全省901个生态功能小区划分为9大类40种类型，并阐述了各类生态功能小区的生态环境特征和生态建设重点。     

音乐(Music)——音乐的分类和作为普遍意义上的音乐

本文是新格罗夫音乐词典中的music词条,文中论述了欧洲早期的音乐分类方法,以及其他不同地域、不同时期有关音乐的分类方法如印度等,涉及了自然音乐、人工音乐等几种形式,还对音乐的普遍意义特征作了深入地剖析。     

新立城水库大坝安全管理信息系统

大坝安全监测信息实时查询、实时分析对大坝管理十分重要，本文简要介绍了新立城水库大坝安全管理信息系统的功能及结构，其良好的稳定性和可靠性，提高了水库管理的自动化水平。     

书法教育的功能说

书法是中华民族文化的结晶和象征,荟萃了中华民族文化的精髓,有着博大精深的文化内涵和巨大的文化魅力,书法教育是促进素质教育的必然要求和重要手段,书法教育在提高学生文化素质、智能素质、审美素质以及强化人格力量诸方面具有其它学科无法替代的功能。     

新型二异羟肟酸配合物催化PNPP水解的动力学研究

以3种含中心功能基(-OCH3)的二异羟肟酸开链冠醚过渡金属铜(Ⅱ)、锌(Ⅱ)和钴(Ⅱ)配合物作为水解酶模型,催化羧酸酯(PNPP)水解;研究了水解反应的动力学和机理,提出了水解反应的动力学模型。结果表明:在室温25℃条件下,这类配合物催化PNPP水解速率随着缓冲溶液pH值的增大而提高,表现出高的催化活性。     

中老年人心血管功能对长期登山锻炼应答的实验研究

采用追踪实验法，对坚持登山锻炼的12名（45～66岁）中老年被试进行六年时间的追踪研究，观察心血管功能对登山锻炼的应答。结果表明：登山锻炼能够增大被试的肺活量，降低血压，减缓心率，促进血脂代谢的改善，提高心血管的适应力。同时发现：除LDL—C外，血脂代谢中的TG、TC和HDL—C水平的变化与个体状况有关，通用理论并不完全适用。     

Importance of NPA motifs in the expression and function of water channel aquaporin-1

The asparagine-proline-alanine sequences (NPA motifs) are highly conserved in aquaporin water channel family. Crystallographic studies of AQP1 structure demonstrated that the two NPA motifs are in the narrow central constriction of the channel, serving to bind water molecules for selective and effi-cient water passage. To investigate the importance of the two NPA motifs in the structure, function and biogenesis of aquaporin water channels, we generated AQP1 mutations with NPA1 deletion, NPA2 de-letion and NPA1,2 double deletion. The coding sequences of the three mutated cDNAs were subcloned into the mammalian expression vector pcDNA3.1 to form expression plasmids. We established stably transfected CHO cell lines expressing these AQP1 mutants. Immunofluorescence indicated that all the three mutated AQP1 proteins are expressed normally on the plasma membrane of stably transfected CHO cells, suggesting that deletion of NPA motifs does not influence the expression and intracellular processing of AQP1. Functional analysis demonstrated that NPA1 or NPA2 deletion reduced AQP1 water permeability by 49.6% and 46.7%, respectively, while NPA1,2 double deletion had little effect on AQP1 water permeability. These results provide evidence that NPA motifs are important for water per-meation but not essential for the expression, intracellular processing and the basic structure of AQP1 water channel.     

Bow-tie topological features of metabolic networks and the functional significance

Exploring the structural topology of genome-based large-scale metabolic network is essential for in- vestigating possible relations between structure and functionality.Visualization would be helpful for obtaining immediate information about structural organization.In this work,metabolic networks of 75 organisms were investigated from a topological point of view.A spread bow-tie model was proposed to give a clear visualization of the bow-tie structure for metabolic networks.The revealed topological pattern helps to design more efficient algorithm specifically for metabolic networks.This coarse- grained graph also visualizes the vulnerable connections in the network,and thus could have important implication for disease studies and drug target identifications.In addition,analysis on the reciprocal links and main cores in the GSC part of bow-tie also reveals that the bow-tie structure of metabolic networks has its own intrinsic and significant features which are significantly different from those of random networks.     

Investigation of adsorption of surfactant at the air-water interface with quantum chemistry method

Density functional theory （DFT） of quantum chemistry was used to optimize the configuration of the anionic surfactant complexes CH3（CH2）7OSO3^- （H2O）n （n=0-6） and calculate their molecular frequencies at the B3LYP/6-311＋G^＊ level. The interaction of CH3（CH2）7OSO3^- with 1 to 6 water molecules was investigated at the air-water interface with DFT. The results revealed that the hydration shell was formed in the form of H-bond between the hydrophilic group of CH3（CH2）7OSO3^- and 6 waters. The strength of H-bonds belongs to medium. Binding free energy revealed that the hydration shell was stable. The increase of the number of water molecules will cause increases of the total charge of hydrophilic group and S10-O9-C8 bond angle, but decreases of the alkyl chain length and the bond lengths of S10-O11, S10-O12 as well as S10-O13, respectively.