TT''''-free图的最长圈

本文提出了两类新的禁用子图T和T＇.一个图G称为TT＇-free图,若G中不含同构于T或T＇的导出子图,它是比无爪图更广的一个图类.G的一个圈C称为控制圈（简记为D-圈）,若E（G-C）=φ.本文证明了：顶点数不小于3的连通、局部连通TT＇-free图G最长圈为D-圈,且G是局部泛圈的.     

Calcium carbonate pump during Quaternary glacial cycles in the South China Sea

The preservation and dissolution of calcium carbonate (namely calcium carbonate pump) controls the pH of seawater in global oceans by its buffer effect, and in turn plays a significant role in global changes in atmospheric CO2 concentration. The results from measured carbonate contents over the past 2 Ma at ODP Site 1143 in the South China Sea provide high-resolution records to explore the process of the calcium carbonate pump during Quaternary glacial cycles. The results indicate statistically that the highest carbonate accumulation rate leads the lightest δ^18O by about 3.6ka at transitions from glacials to interglacials, and that the strongest carbonate dissolution lags the lightest δ^18O by about 5.6 ka at transitions from interglacials to glacials. The calcium carbonate pump releases CO2 to the at mosphere atthe glacial-interglacial transitions, but transports atmospheric CO2 to deep sea at the interglacial-glacial transitions.The adjustable function of the calcium carbonate pump for the deep-sea CO3^2- concentration directly controls parts of global changes in atmospheric CO2, and contributes the global carbon cycle system during the Quaternary.     

Business Action Research in Practice—A Strategic Conversation About Conducting Action Research in Business Organizations

The objectiveof this paper is to provide practitioner researchers with insights into the initial findings around the challenges of conducting business action research in practice in commercial settings on the basis of experiences of a PhD cohort at Monash University in the first 18 months of candidature. In performing the role of a concluding paper, it sets out a generic framework for action research that the cohort has come to embrace. In doing so, it draws on emergent themes spread across the six diverse topics that are the subject of action research interventions of the cohort members. The paper then identifies and analyses the common patterns that have emerged and offers observations and conclusions for those involved in practitioner research.     

以三次曲线xy^2=ax^3＋cx＋d为解的三次系统

本文讨论了以三次曲线xy~2=ax~3+cx+d为解的三次系统,给出了这类系统的一般形式,我们证明了当xy~2=ax~3+cx+d没有闭分支时,以其为解的三次系统不存在极限环;当xy~2=ax~3+cx+d存在闭分支时,以其为解的三次系统可以以该闭分支为极限环,同时我们也给出了闭分支为唯一极限环和不存在极限环的充分条件。     

Suppression of annual plasma testosterone and thyroxine cycles in the edible dormouseGlis glis under constant photoperiod at 24°C

Summary Exposure of male ebible dormice all year round to an unwarying photoperiod and warm temperature disrupted their biological cycles; hibernation was almost completely suppressed, and short lived infradian cycles of body weight, and of plasma testosterone and thyroxine were measured instead of the normal annual patten.     

基于米兰柯维奇理论的地层划分新方法

提出了以米兰柯维奇理论为基础的地层划分新方法 ,该方法利用频谱中峰值频率的位置进行旋回识别。定义了岁差和斜率的旋回发育状况函数 ,利用该函数来反映地层中米兰柯维奇旋回的发育程度 ,并据此分析了地层的连续性、判断出沉积间断的位置及进行了地层划分。研究结果表明 ,利用地层中存在的米兰柯维奇旋回可以进行精细地层划分 ,划分结果可进行远距离对比。该方法在大港油田、胜利油田、塔河油田的实际应用中取得了较好的效果 ,具有准确性高、效率高、应用范围广的特点。     

一类五次系统的中心条件和极限环分支

本文利用计算机代数系统Mathematica，计算并化简了一类五次系统的焦点量，同时得出了该系统的三个不同奇点成为中心的条件与极限环分支的情况．     

新疆北山晚古生代克拉通裂谷火山作用特征

新疆北山构造带克拉通裂谷活动期火山活动频繁,火山作用较强烈.区内晚古生代火山岩分布广泛,集中发育于下石炭统上部、上石炭统和下二叠统,与正常沉积岩呈断续间互层状产出.据岩石地层研究、火山岩产状及接触关系,划分为4个火山旋回,共9个火山喷溢韵律.在对区内火山岩地质特征、岩石类型、岩石化学和稀土元素地球化学特征研究基础上,探讨了火山岩的演化特点和形成环境.     

一类非Liénard型三次系统的定性研究

对于平面系统的极限环问题,有大量关于Lienard型系统的结论,但对非Lienard型系统,例如x=-y+ ψ(x),y=x+ψ(y)型的系统,则很少有研究结果.本文对ψ(x)为x的三次式,ψ(y)为y的一次式所对应的系统给出了其全局轨线结构的完整分析,特别是证明了该系统的极限环的不存在性、存在性与唯一性的相应结论.     

中国黄土—古土壤序列与第四纪古气候旋回——研究现状、问题与前瞻

中国黄土—古土壤序列记录了过去2.4Ma地质和气候事件的演化历史,总结这方面研究的最新成就和存在的问题,提出了今后应重视的研究方向。