给水系统附生生物膜发育的生物量和种群结构

为了满足给水管网管水质的要求,考察了不同的给水管道水力条件下,聚乙烯管材上生物膜(生物量和种群结构)的发育情况。采用分子生物学与传统分离培养相结合的方法,以清华地下水为原水,在剪切力分别为0.95、0.18Pa两种条件下,生物膜生物量和种群结构的发育呈现了同一规律,即生物膜生物量在7d内即可发育成熟,在以后的发育中,生物膜生物量一直稳定在105CFU/cm2(CFU为菌落形成单位),但生物膜的种群结构却随着时间发生显著变化。实验中所设置两种水力条件对生物膜发育的影响差别不大;生物膜生物量的发育和种群结构的发育是两个相对独立的过程;易于分泌胞外粘液和菌体表面具有疏水性等性质可以帮助细菌更好地在生物膜中生存发展。     

冗余并联机床驱动力优化解析

驱动冗余可有效消除并联机构在作业空间中的奇异位形,但其导致驱动力分配不唯一。该文针对一台4自由度的冗余并联机床进行了驱动力解析。在运动学分析基础上,得到各支链的偏速度矩阵及偏角速度矩阵,解算各支链的合力/力矩,利用虚功原理建立了该机构的逆动力学方程,并将其变换为线性格式,然后针对驱动冗余的特点,对驱动力分别进行了力优化及能耗优化,其中,力优化计算简单,而能耗优化可降低最大驱动力。该模型适用于冗余并联机构的动力学参数辨识以及动力学控制。     

秦岭北麓大鲵亲体繁育实验研究

叙述了秦岭北麓大鲵繁育基地的自然环境与仿生态池的给养条件及亲鲵单池单养和同池隔网单养的培育方式.对大鲵3年连续催情32组,结果自然交配产卵雌鲵27尾,共获卵14 000粒,并连年孵化出苗.其中,产空卵带亲鲵5尾,催繁成功率为84.4%.论述了亲鲵耐受低温的能力,发现其早春低水温>4℃时开食,个性凶残,每年7月下旬至8月底性腺发育成熟,为最佳催情期.交配产卵池应彻底清池,严格控制给水流量与水深以及亲鲵繁殖与护卵行为等.展望了大鲵规模化养殖的前景.     

惠州市植物叶片和叶面降尘的重金属特征

用ICP-AES测定了惠州市不同功能区的典型绿化树种大叶榕和紫荆叶片及其叶面降尘的重金属含量。结果表明,不同功能区植物叶片和叶面降尘的重金属含量差异显著,植物叶片综合污染指数为:商业交通区>工业区>居民区>清洁区,而叶面降尘的综合污染指数则为:工业区>商业交通区>居民区>清洁区。大叶榕叶片的重金属含量略高于紫荆,但差异不显著。降尘重金属污染严重,尤其Cd含量达到了广东省土壤背景值的120倍以上,Pb则为12倍以上。降尘重金属含量是叶片的2～800倍,通过叶片气孔吸收的降尘重金属较少。植物叶片和降尘的重金属含量随交通流量的减少而降低。除Cr和Cd元素外,大叶榕与紫荆叶片的重金属与叶面降尘中重金属相关性不显著。     

Rough Sets and Nuclear Safety

It is well-known that rough set theory can be applied successfully to rough classification and knowledge discovery. Our work is concerned with finding methods for using rough sets to identify classes in datasets, finding dependencies in relations and discovering rules which are hidden in databases by means of decision tables and algorithm D. We use these methods to analyze and control aspects of nuclear energy generation.     

来自自然界的可再生能源-生物质乙醇重整制氢

在镧系金属氧化物载镍催化剂上通过催化重整乙醇和乙醇水溶液可以直接转化为H2，H2的选择性达到60％，乙醇的转化率达到100％。优化催化剂及降低重整反应的温度以使水汽转化反应同时发生来降低产物气中CO的含量。该过程对于生产小型燃料电池的低成本燃料H2，以及便携燃料电池系统需要液态燃料存储的应用具有巨大的潜在价值。     

利用量子纠缠降低通讯复杂性

从生物与物理结合处入手,主要介绍了运用逼近的方法来计算在纠缠状态下,传递更少的数据时,通讯双方通讯成功的概率,以此理论来降低通讯的复杂性.经过几个周期的计算,得到的数据逐渐接近,但没有超过前人计算的数值.由此可以用前人的结果来作为此通讯概率的上限.     

Promoted Cytocompatibility of Silk Fibroin Fiber Vascular Graft through Chemical Grafting with Bioactive Molecules

Natural silk from Bombyx mori has been used as medical sutures for several decades,and regenerated silk fibroin( RSF)based biomaterials have been increasingly studied in the past thirty years. However,vascular graft derived from silk fibroin fiber has been explored in recent several years with development of textile science and engineering. Moreover,endothelialization of vascular graft has been seen as an ideal strategy for preventing thrombosis and getting higher patency in a long term. Therefore,in the present work silk fibroin fiber vascular graft( SF) was chemically grafted with bioactive molecules such as heparin and RSF to improve the cytocompatibility. 3-aminopropyl-triethoxysilane(APTES),1-ethyl-3-(3-dimethylaminopropyl) carbodiie hydrochlide( EDC · HCl),and N-hydroxysuccinimide( NHS) have been employed as coupling agent and crosslinking agents,respectively. Microscopy and ATRFTIR were used to characterize the surface changes and the structure of the grafts after treatment,respectively. Cell culture in vitro and MTT assay were conducted to determine the improvement of cell affinity to the graft. Furthermore,mechanical properties of the grafts before and after treatment were compared. The results showed that the chemical grafting was an effective method for improving the cytocompatibility of SF without significant loss of mechanical properties.     

Electronic properties and stabilities of methoxy-substituted Lindqvist polyoxometalates [Nb2W4019CH3]3- by DFT

The electronic properties and stabilities of five [Nb2W4O18OCH3]3-isomers have been investigated using a density functional theory method.The results show that the isomer with the methoxy group occupying a bridging position between two tungsten atoms(two tungsten atoms in the plane that contains two niobium atoms) in the [Nb2W4O18OCH3]3-framework is the most stable isomer in acetonitrile.The stability of the one-electron-reduced isomers changes little.The most stable one-electron-reduced isomer has the methoxy group occupying a bridging position between niobium atoms in the [Nb2W4O18OCH3]4-framework.The M-Ob(M = Nb,W;b denotes bridging) bond lengths in anions in which the metal atoms are connected by a methoxy group are longer than those in [Nb2W4O19]4-.The highest occupied molecular orbitals(HOMO) in [Nb2W4O19]4-mainly delocalize over the bridging oxygen atoms of two niobium atoms and two tungsten atoms located in the equatorial plane,and the bridging oxygen atoms on the axial surface.The lowest unoccupied molecular orbitals(LUMO) of [Nb2W4O19]4-are mainly concentrated on the tungsten atoms and antibonding oxygen atoms.Methoxy substitution modifies the electronic properties of the [Nb2W4O18OCH3]3-isomers.The HOMOs in the five isomers formally delocalize over the bridging oxygen atoms,which are distant from the surface containing the methoxy group and four metal atoms.The LUMOs delocalize over the d-shells of the four metal atoms that are close to the methoxy group,and the p-orbitals of oxygen.One-electron reduction occurred at the tungsten atoms,not the niobium atoms.     

主题乐园游乐服务质量指标及满意度评价研究

我国相当数量的主题乐园生命周期短，对游客重游吸引力低，这与难以找准评估影响主题乐园游乐质量的主要因素，有针对性的改进，吸引顾客重游有很大关系。寻求影响游乐质量的主要因素并用一种合适的模式对其进行评价对主题乐园的理论发展和实际运营都有很好的价值。为此，我们借鉴国内外文献找到评价主题乐园服务质量的指标及评价模式，并以成都国色天乡乐园对国内的主题乐园进行了实证检验。并对实证结果进行了讨论，得出了一些有意义的结论。