医药学院校物理实验课教学现状及教学改革设想

分析了华北地区本科医药类16所院校物理实验课教学现状，并与国外情况进行了比较，提出了教学改革设想．     

关于Katz指标的二级分裂迭代方法

本文研究复杂网络中计算Katz指标的迭代法,基于网络拓扑结构,在快速Katz指标算法的基础上,运用二级分裂迭代思想,提出了具有两个参数的二级分裂迭代法,并研究了该方法的收敛性.基于该方法的收缩因子的计算公式,讨论了迭代参数可能的选择,通过参数的选择能有效提高二级迭代法的收敛效率.最后通过数值实例验证了此方法的有效性.     

Ultrastructural changes to rat hippocampus in pentylenetetrazol- and kainic acid-induced status epilepticus: A study using electron microscopy

A pentylenetetrazol (PTZ)-induced status epilepticus model in rats was used in the study. The brains were studied one month after treatment. Ultrastructural observations using electron microscopy performed on the neurons, glial cells, and synapses, in the hippocampal CA1 region of epileptic brains, demonstrated the following major changes over normal control brain tissue. (i) There is ultrastructural alterations in some neurons, glial cells and synapses in the hippocampal CA1 region. (ii) The destruction of cellular organelles and peripheral, partial or even total chromatolysis in some pyramidal cells and in interneurons are observed. Several astrocytes are proliferated or activated. Presynaptic terminals with granular vesicles and degenerated presynaptic profiles are rarely observed. (iii) The alterations observed are found to be dependent on the frequency of seizure activities following the PTZ treatment. It was observed that if seizure episodes are frequent and severe, the ultrastructure of hippocampal area is significantly changed. Interestingly, the ultrastructure of CA1 area is found to be only moderately altered if seizure episodes following the status epilepticus are rare and more superficial; (iv) alterations in mitochondria and dendrites are among the most common ultrastructural changes seen, suggesting cell stress and changes to cellular metabolism. These morphological changes, observed in brain neurons in status epilepticus, are a reflection of epileptic pathophysiology. Further studies at the chemical and molecular level of neurotransmitter release, such as at the level of porosomes (secretory portals) at the presynaptic membrane, will further reveal molecular details of these changes.     

Classifying inputs and outputs in data envelopment analysis

In conventional data envelopment analysis it is assumed that the input versus output status of each of the chosen performance measures is known. In some situations, however, certain performance measures can play either input or output roles. We refer to these performance measures as flexible measures. This paper presents a modification of the standard constant returns to scale DEA model to accommodate such flexible measures. Both an individual DMU model and an aggregate model are suggested as methodologies for deriving the most appropriate designations for flexible measures. We illustrate the application of these models in two practical problem settings.     

Vitamin D analysis in plasma by high performance liquid chromatography (HPLC) with C(30) reversed phase column and UV detection--easy and acetonitrile-free

Two physiologically important forms of vitamin D exist: vitamin D₂ and vitamin D₃, which by liver based hydroxylase enzymes are converted to 25-hydroxyvitamin D₂ and 25-hydroxyvitamin D₃, respectively. These hydroxylated metabolites of vitamin D are measured in plasma to assess the vitamin D status of animals and humans. Therefore cheap and reliable analytical methods are very much in demand in nutritional and physiological research. After saponification and extraction of plasma or serum samples the current method uses reverse phase high performance liquid chromatography on a C₃₀ column and with UV detection at 265 nm for quantifying vitamin D₂, vitamin D₃, 25-hydroxyvitamin D₂, and 25-hydroxyvitamin D₃. The method proved versatile with respect to plasma lipid content, sample amount, and plasma concentration of the vitamin D metabolites as it was tested using plasma from six different species: cattle, pigs, poultry, mink, horses, and humans. In cattle plasma recoveries were between 86.6 and 101.0%, within day error between 0.9 and 5.9%, and between day error between 0.2 and 1.7%. However, depending on species and sample amount error percentages varied. When running the method on standard reference material^® 972 “Vitamin D in human serum” from the National Institute of Standards and Technology (NIST) (Gaithersburg, USA) the results for 25-hydroxyvitamin D₂ and 25-hydroxyvitamin D₃ concentrations were within the boundaries provided by NIST, reflected by Z-scores between 0.1 and 0.9.     

考虑地位效应时炫耀性虚拟商品的最优定价与普及版本化

考虑地位效应的影响,针对炫耀性虚拟商品,决策最优定价和普及版本化。建立了单标准版策略、双版本免费普及策略和双版本销售策略等三种模型,求解得到企业在对应策略下对单版本或双版本的炫耀性虚拟商品的最优定价,在此基础上分析得到地位效应对虚拟商品价格、企业利润和最优普及版本化策略的影响。研究发现地位效应是导致标准版炫耀性虚拟商品价格和企业利润提升的因素;当存在地位效应时,双版本销售策略是炫耀性虚拟商品的最优普及版本化策略;但双版本销售策略相比于单标准版策略的优势在一定条件下因网络外部性增强而削弱。     

多指标约束的斜拉索滑模非脆弱减振控制

为了提高斜拉索-磁流变阻尼器减振控制系统的稳定性, 提出了一种多指标约束的滑模非脆弱减振控制算法. 基于线性矩阵不等式(LMI), 利用H∞性能指标和保性能指标分别用来抑制外界扰动, 保证系统渐近稳定且具有一定上界指标, 并以区域极点配置表征减振控制稳定性与快速性, 方差表征小振幅和振动速度. 将非脆弱状态反馈控制与滑模控制相结合, 得到了多指标约束的滑模非脆弱减振控制算法设计形式及方法. 在强度为0.1002高斯白噪声随机扰动下, 对某跨海大桥C18、C13号斜拉索进行算例仿真. 结果表明, 该算法不仅使减振控制系统具有较优的保性能上界指标和较小的抗扰性能指标, 同时使拉索振动状态幅值降低91.11%~92.50%, 收敛时间缩短76.67%~84.00%.     

农民健康状况对农业生产效率影响的实证研究

利用2012年福建安溪随机抽样的335茶农的调查数据,探讨农民健康状况对农业生产效率的影响。通过建立随机前沿生产函数,对茶叶生产的效率损失值进行了测算;以健康损害为关键变量、农户家庭特征和其他变量为控制变量,对效率损失值进行Tobit回归。结果显示,农业生产效率不仅受到劳动、茶园面积、化学要素投入量等传统要素的影响,而且与农民的健康状况显著正相关,说明投资于健康对农民增产增收至关重要。     

化学教育究竟是怎样的一个研究领域

针对"化学教育"作为一个科学研究领域在我国认同度不高的现状,讨论了开展化学教育研究的必要性,化学教育研究的起源及其国际学术地位,化学教育研究与化学研究的相似性,化学教育研究的特殊性,化学教育研究应遵循的科学原理.     

基于TPACK研究手持技术在中学化学课堂教学的应用现状

为了解中学化学教师对手持技术的应用水平和影响因素。以整合技术的学科教学知识（TPACK）理论为依据,创新性地将境脉（Context）因素引入TPACK调查中进行问卷设计,并对来自于全国16个省直辖市的187位教师进行了网络问卷调查,同时采用SPSS软件对问卷进行信效度评价,采用SPSS AMOS对问卷进行探索性因子分析,并对调查结果进行分析。研究结果显示中学化学教师手持技术TPACK量表结构模型较好,能够用于评价中学化学教师的手持技术应用水平;中学化学教师手持技术应用情况良好,但是与性别、教龄、学校类别有显著关系。针对研究结果,提出提高中学化学教师手持技术应用水平的发展建议,以期提高中学化学教师手持技术在中学化学教学的应用水平。