南极菲尔德斯半岛六种藻类和地衣植物的X荧光分析

为了研究南极的植物与环境间的关系,探讨植物在南极环境监测中的作用。在无标样条件下,利用微束X荧光分析法对南极菲尔德斯半岛的6种藻类和地衣植物进行了元素分析．其中藻类植物有孔石莼(Ulva pertusa)、海膜（Halymenia sp.)和大型鞘丝藻（Lyngbya maijor),地衣植物有筛石蕊(Cladonia borealis)、喇叭石蕊（C.fimbriata)和松萝(Usnea sp.)．研究结果发现,不同的藻类植物对各种元素的吸收能力不同,在XRF（X射线荧光)谱中,孔石莼比海膜含有更多的元素,象As、Br和Rb,Cu和Zn的含量也较高。在大型鞘丝藻中,K比Ca少,Zn的含量较高．在3种地衣植物中,其XRF谱中的元素种类组成非常相似,只是Mn、Fe、Cu和Zn等元素的相对含量有些差异。     

SIZE EFFECT AND GEOMETRICAL EFFECT OF SOLIDS IN MICRO—INDENTATION TEST

Micro-indentation tests at scales of the order of sub-micron show that the measured hardness increases strongly with decreasing indent depth or indent size,which is frequently referred to as the size effect.At the same time,at micron or sub-micron scale,another effect,which is referred to as the geometrical size effects such as crystal grain size effect,thin flim thickness effect,etc.,also influences the measured material hardness.However,the trends are at odds with the size-independence implied by the conventional elastic-plastic theory.In the present research,the strain gradient plasticity theory(Fleck and Hutchinson)is used to model the composition effects(size effect and geometrical effect) for polycrystal material and metal thin film/ceramic substrate systems when materials undergo micro-indenting.The phenomena of the “pile-up“ and “sink-in“ apeared in the indentation test for the polycrystal materials are also discussed.Meanwhile,the micro-indentation experiments for the polycrystal Al and for the Ti/Si3N4 thin film/substrate system are carried out.By comparing the theoretical predictions with experimental measuremtns.the values and the variation trends of the micro-scale parameter included in the strain gradient plasticity theory are predicted.     

化学高考结构效度初探

任何考试总是为了一定的测量目的而编制的,判断它是否有效（效度）,主要看它达到测验目标的程度。如果通过考试能测量出所要测量的特性,我们称这次考试是有效的。     

甲酸脱氢酶催化活性的定向进化及其高效表达

甲酸脱氢酶(formate dehydrogenase,FDH)属于D-2-羟基酸脱氢酶类,能催化甲酸氧化生成二氧化碳,同时能将氧化型辅酶 1(Oxdized form of nicotinamide adenine dinucleotide,NAD+)还原成还原型辅酶 I(Redued form of nicotin...     

一种基于欧氏干扰因子的微粒群优化算法的改进

针对基本微粒群优化(PSO,Particle Swarm Optimization)算法在应用于具有极多局部极值和维数被优化问题时易陷入局部最优和早熟收敛的不足,提出了一种新的改进算法称之为欧氏微粒群算法.此改进算法的主要思想是当算法陷入局部最优时,给微粒一个扰动因子,它的大小会因当前微粒与全局最优微粒的欧式距离的大小而自适应变化,促使微粒跳出局部最优.在实验中选取典型标准函数对算法进行测试,实验结果表明,本文算法优于标准微粒群算法(SPSO)和高斯微粒群算法(GPSO),而且随着问题复杂性的提高其性能优越性越明显.     

无花果醋饮料生产工艺的研究

以残次无花果干,落地无花果干为原料生产无花果醋饮料.通过实验研究确定了生产无花果醋饮料最佳工艺条件及操作参数.分析了影响无花果醋饮料风味的因素.通过实验研究确定了无花果醋饮料的最佳配方设计.     

K2NaAlF6:Ce3+和KAlF4:Ce3+磷光体的光谱特性

采用高温固相反应法,在Ar气氛中,合成了K2NaAlF6和KAlF4基质化合物.分别测定了它们的结构,并计算了晶胞参数.测定了K2NaAlF6:Ce3+和KAlF4:Ce3+磷光体的激发光谱和荧光光谱,根据Ce3+的光谱结构的特点,讨论了Ce3+的取代格位.     

CaAl3BO7：RE(RE=Ce,Gd,Tb)中稀土离子的光谱特性

采用固相反应法合成了CaAl₃BO₇RE(RE=Ce,Gd,Tb),研究了Ce³⁺,Gd³⁺和Tb³⁺的光谱特性。发现铈离子周围存在较强的晶场,使基态的4f能级劈裂较大,从而导致铈离子的特征发射峰重叠较大;Ce³⁺的5d能级明显低于Gd³⁺的⁶I、⁶P能级;Ce³⁺和Tb³⁺之间存在有效的能量传递。     

激光光热光谱痕量微化学分析方法研究

本文从理论和实验上对那些适合于小体积样品分析的激光光热光谱分析方法进行比较，探讨采用激光光热光谱法进行痕量微化学分析的可行性。     

Near-field manipulation of terahertz surface waves by metasurfaces [Invited]

Surface waves(SWs) are a special form of electromagnetic waves that travel along the boundary between a metal and a dielectric. The special optical properties of SWs render them very attractive in applications, such as subdiffractional lithography, novel biochemical sensors, and ultrafast integrated circuitries. Herein, we present a review of our recent progress in excitation and manipulation of terahertz SWs due to interference or coupling between a pair of slit resonators in metasurfaces, showing the ability to devise ultrathin and compact plasmonic components.