一类具有脉冲效应的渔业模型的最优控制

提出了具有脉冲效应的渔业模型,利用最优脉冲控制原理,得出最优捕获时刻以及相应的最优捕获水平．最后,利用数值模拟验证结论的有效性．     

一对称矩阵方程组解的研究

给出了四元数体上一对称矩阵方程组有斜埃尔米特解的充分必要条件,并得到了此方程组的斜埃尔米特解的一般表达式。应用主要结果讨论了四元数矩阵A和B矩阵有共同的斜埃尔米特广义逆的充要条件及斜埃尔米特广义逆的表示。     

关于Mordell方程y^2=x^3＋k

设l,l1,l2,…,ls为任意整数,n为正整数,n1,n2,…,ns为任意非负整数．用初等数论方法证明了：如果k满足k=（4l＋2）^3-Пi=1^s（4li＋1）^2ni或k=（4l＋3）^3-2^2nПi=1^s（4li＋1）^2ni,则Mordell方程y^2=x^3＋k无整数解．     

植酸保鲜剂对月季切花O_2~-产生速率和还原糖含量的影响

本文研究了浓度分别为0.13%与0.013%的植酸保鲜液对一种名为＂Shasha 90#＂的红色月季的保鲜效果,同时以蒸馏水为对照,每批次处理重复三次。通过测定切花的瓶插寿命,超氧阴离子自由基（O2-）产生速率、还原糖含量等生理指标来判断植酸保鲜液对月季切花的影响。结果表明,0.13%与0.013%的植酸保鲜液均能够延长月季切花的瓶插寿命,降低超氧阴离子自由基（O2-）的产生速率,减少还原糖的损失。而浓度为0.13%的植酸保鲜液比0.013%的效果要好。     

Simplexmethod建模研讨

目的 Linear Programming的simplexmethod建模求最优解。方法应用simplexmethod.结果建立了LinearProgramming的数学模型并用simplexmethod求得了最优解.结论因为单纯形表反映了Linear Programming的所有信息,故用simplexmethod可简便地求得最优解.simplexmethod的基本思路是：先将Linear Programming用sim-plexmethod划为标准型,根据问题的标准型,进行初等行变换,将主元素列除主元素化为1外其余的元素均化为0,当基变量值全为非负时,问题就得到了最优解.     

金樱子提取物的流变性研究

测定不同条件下金樱子提取物溶液的粘度变化,对其流变性能进行研究.结果表明：金樱子提取物溶液为＂非牛顿流体＂,其粘度随着溶液浓度的增加而增加,当溶液浓度达到1.4 mg/ml时成凝胶状;该溶液在碱性条件下比较稳定,具有良好的耐盐稳定性和抗降解性能;冻融变化使该溶液的粘度有所增加,且冷冻处理后的效果更明显;苯甲酸钠、微波等...     

Anisotropic fluoride nanocrystals modulated by facet-specific passivation and their disordered surfaces

Rutile-type fluorides have been proven to be active components in the context of emerging antiferr-omagnetic devices. However, controlled synthesis of low-dimensional, in particular two-dimensional (2D), fluorides in a predictable and deterministic manner remains unrealized because of a lack of efficient anisotropic control, which impedes their further development in reduced dimensions. We report here that altered passivation of {110} growing facets can direct the synthesis of rutile-type fluoride nanocrystals into well-defined zero-dimensional (0D) particulates, one-dimensional (1D) rods and 2D sheets in a colloidal approach. The obtained nanocrystals show positive exchange bias and enhanced magnetic transition temperature from the coexistence of long-range antiferromagnetic order and disordered surface spins, making them strong alternatives for flexible magnetic devices and sensors.     

Large-scale multiferroic complex oxide epitaxy with magnetically switched polarization enabled by solution processing

Complex oxides with tunable structures have many fascinating properties, though high-quality complex oxide epitaxy with precisely controlled composition is still out of reach. Here we have successfully developed solution-based single-crystalline epitaxy for multiferroic (1-x)BiTi_(1-y)/2Fe_yMg_(1-y)/2O₃–(x)CaTiO₃ (BTFM–CTO) solid solution in large area, confirming its ferroelectricity at the atomic scale with strong spontaneous polarization. Careful compositional tuning leads to a bulk magnetization of 0.07 ± 0.035 μ_B/Fe at room temperature, enabling magnetically induced polarization switching exhibiting a large magnetoelectric coefficient of 2.7–3.0 × 10⁻⁷ s/m. This work demonstrates the great potential of solution processing in large-scale complex oxide epitaxy and establishes novel room-temperature magnetoelectric coupling in epitaxial BTFM–CTO film, making it possible to explore a much wider space of composition, phase, and structure that can be easily scaled up for industrial applications.     

论大学生的科研能力及培养途径

培养具有创新精神和实践能力的高级专门人才,发展科学技术文化,是高等教育的历史使命。在高校中大力推进“科教兴国”战略的实施和科学技术创新,努力培养广大青年学生的科学研究能力,使其具备一定的创新意识、创造能力和创业精神,造就一代适应未来挑战的高素质人才,已经成为当代教育发展的必然要求。     

高职英语听力教学的障碍与解决方法

听是英语应用能力的主要体现,对高职学生尤为重要。目前,高职英语听力教学中还存在很多障碍,尤以应试教育机制、教学设备、教材和学生心理因素等问题最为突出。如果采取合理的措施,这些问题是可以解决的。