一类求解抛物型方程侧边值问题的最优滤波方法

该文考虑一类特殊的抛物型方程侧边值问题,即一类含有对流项的非标准逆热传导问题. 给定在x=1处的温度测量值来确定区间(0,1)上的未知解u(x, t). 这是一类不适定问题,即问题的解(如果解存在)不连续依赖于数据.为了求解这一问题, 必须采用某些正则化技巧. 该文给出了一种最优滤波方法, 使得问题的真实解和近似解之间的误差估计达到了Hölder型最优. 同时还证明了问题的解在x=0处的收敛性.     

高师数学专业学生实验能力培养的理论研究与实践

数学实验活动是提高学生数学素养,提高学生应用能力和创造能力的有效途径.高师院校学生肩负着未来培养中小学生的数学探究能力和创造能力的重大使命.因此,高师院校数学实验的教学改革研究具有双重的意义.本文通过对高师院校数学实验课程体系改革的理论研究与教学实践,探讨了高师院校数学实验教学的一条新路,提供了适合高师院校学生数学实验能力培养的新教学模式和新途径.     

Capillary zone electrophoretic chiral discrimination using 6-O-(2-hydroxy-3-trimethylammoniopropyl)-beta-cyclodextrin as a chiral selector

A charged highly water-soluble CD derivative, 6-O-(2-hydroxy-3-trimethylammoniopropyl)-beta-CD (herein noted as 6-HPTMA-beta-CD) was synthesized and successfully used as a chiral selector for enantiomeric separation of some acidic compounds by CZE in an uncoated capillary. Substitution with 2-hydroxy-3-trimethylammoniopropyl groups at the primary hydroxyl group of the CD was aimed at influencing the magnitude and selectivity of analyte-CD interactions. The behavior of 6-HPTMA-beta-CD was compared with that of the commercially available quaternary ammonium-beta-CD (QA-beta-CD) under the same separating conditions. The experiments were carried out using a BGE consisting of 50 mM phosphate in the pH range of 4-6 by adding a relatively low concentration of chiral selector (less than 10 mM). The effects of the concentration of CD and the pH of the electrolyte on the resolution of these compounds were studied.     

A sheath-flow nanoelectrospray interface of microchip electrophoresis MS for glycoprotein and glycopeptide analysis

Microchip was coupled with MS through a stable, sensitive, and controllable sheath-flow nanoelectrospray (nES) interface for glycoprotein and glycopeptide analysis. The nano-ESI (nESI) was made with a delivery capillary, a commercial nES capillary, and a stainless steel (SS) tube which were connected together through a tee unit. High voltage for nES was applied on the SS tube and the commercial nES capillary was used as nES emitter. The delivery capillary was attached to the microchannel for delivering liquid from microchip to the nESI source. The flow rate of sheath liquid was optimized to be 100-200 nL/min which largely reduced the sample dilution. The detection limit of peptides on this microchip/MS platform was at femtomole level. Glycoprotein and glycopeptides were also successfully analyzed on the platform. All the glycoforms and glycopeptides of ribonuclease B (RNase B) were identified with this method. Some structures of the glycopeptides from RNase B were further characterized with MS/MS on the microchip, coupled with a quadrupole IT-MS.     

Proliferation, viability, and metabolism of human tumor and normal cells cultured in microcapsule

In this study, we investigated the effect of the microenvironment provided by alginate-poly-l-lysine-alginate (APA) microcapsule with liquefied or gelled core on the proliferation, viability, and metabolism of human cells, including anchorage-dependent MCF-7 breast cancer cells and primary fibroblasts, and anchorage-independent K-562 leukemia cells; cells in conventional culture were used as control. The growth pattern of cells in microcapsule was examined by phase-contrast micrography. The cell viability, proliferation, organization, and gene expression were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, hematoxylin and eosin staining, live/dead staining, 5-bromo-20-deoxyuridine labeling, and immunohistochemistry, respectively. Cell metabolism was determined by measuring glucose and lactate concentrations in medium. The results demonstrate that APA microcapsule with liquefied core provides a microenvironment for both anchorage-dependent and anchorage-independent cells to grow into a large cell aggregate and maintain cell viability at a constant level for a period of time. In conclusion, cells in APA microcapsule are alive and have proliferation potential with lower metabolism rate. APA microcapsule may be a useful tool for in vitro tumor cell modeling and anticancer drug screening as well as for cancer gene therapy. In addition, it lays a solid foundation for the use of microencapsulation in cell culture in vitro and cell implantation in vivo.     

高效液相色谱法同时检测牙膏中19种合成着色剂

建立了高效液相色谱法(HPLC)同时测定牙膏中19种合成着色剂的检测方法.样品经水分散后超声提取,以10000 r/min离心5min,经0.45μm微孔聚四氟乙烯(PTFE)过滤后取滤液测定.采用Agilent eclipse XDB-C18柱(4.6 mm×150 mm,5μm),以乙腈和20 mmol/L乙酸铵溶...     

Er掺杂SiNP电子结构和光学性质的第一性原理研究

当硅基发光材料得到广泛应用时,为了给硅基材料的设计及应用提供理论依据,利用基于密度泛函理论的第一性原理,对Er掺杂在Si纳米晶粒不同位置的结构稳定性、电子与光学性质进行了研究.结果表明:Er掺杂在Si纳米晶粒的中心位置时,结构最稳定;Er掺杂后的Si纳米晶粒引入了杂质能级,最终导致禁带宽度变窄;掺杂后的Si纳米晶粒在低能区出现了一个新的吸收峰,当Er原子向表面位置移动时,新的吸收峰峰值逐渐减小,甚至消失.     

混凝土静态力学性能的细观力学方法述评

混凝土力学特性是大坝、海洋平台等工程结构抗震设计及仿真分析的前提条件之一,也是目前研究的薄弱环节. 混凝土是一种典型的非均质材料,其宏观力学特性由细观组成来决定.本文总结了目前研究混凝土宏观力学特性的细观力学分析方法,细观有限元法及理论分析法; 阐述了界面过渡区(ITZ)对混凝土性能的影响,简单介绍了混凝土界面过渡区问题的研究现状;介绍了作者提出的混凝土宏观力学性能研究的细观单元等效化分析方法.最后对其未来发展的一些方向和有待进一步研究的问题作了总结.      

三维实体退化虚拟层合梁单元在梁极限承载力分析中的应用

提出采用三维实体退化虚拟层合梁单元计算梁极限承载力的方法。考虑结构的几何非线性和材料非线性,利用该单元编制了极限承载力计算程序,并将其应用于梁极限承载力的分析。计算实例表明,该单元收敛快,稳定性好,在单元数较少的情况下,具有较高的精度。由于能克服块体单元或梁段     

朱家尖潮间带底栖海藻分布特征

2008年5月至2009年2月对浙江舟山朱家尖情人岛潮间带的大型海藻进行了调查,初步查明该潮间带大型海藻的组成、分布和温度属性,并利用相似性指数（Sc）分析了调查海域潮间带大型海藻相似性值.结果表明：采集到的34种海藻隶属3门23属,其中绿藻门（Chlorophyta）7属8种,红藻门（Rhodophyta）14属20种,褐藻门（Phaeophyta）6属6种.春季主要优势种为铁钉菜（Ishige okamura）、孔石莼（Ulva pertusa）、小杉藻（Gigartina intermedia）;夏季为铁钉菜、羊栖菜（Sargassum fusiforme）、小石花菜（Gelidium divaricatum）等;秋、冬季节为铁钉菜.红藻门种类在调查海域的出现频率为58.8%,为优势门类;绿藻门种类在该海域的总体水平分布呈均匀状态.70.6%的调查种类分布在低潮带,其中包括一些中潮带延伸种类,中、低潮带的海藻组成相似性值为0.36,并且中、低潮带的生境趋同效果大于高、中潮带.朱家尖潮间带大型海藻具有明显的垂直分带现象,温水性种类占绝对优势,优势种多为暖温性种.