天然浮石粉对水泥土力学性能的影响

为充分利用当地自然资源,改善路基施工过程中的软弱地基现状,用浮石粉水泥土试件进行了不同水泥掺量、不同浮石粉掺量的水泥土三轴剪切试验,进一步分析了水泥土的力学性能,通过三轴剪切试验测得不同围压下水泥土的应力—应变曲线、峰值强度等力学指标.试验结果表明:随着水泥掺量的增加,浮石粉水泥土的抗剪强度增大,但水泥掺量达到16％以...     

流域水污染治理模式创新研究

我国严峻的流域水污染已成为可持续发展的严重威胁,而目前的流域水污染治理模式却难以有效地解决这一难题.针对流域水污染防治的管理体制、机制、政策体系所存在问题,提出了创新流域水污染治理模式的对策与方法.     

基于ANSYS的多尺度GO-CF/EP复合材料弯曲性能仿真及试验验证

石墨烯-碳纤维混杂增强树脂基(GO-CF/EP)复合材料以其低密度和优异的力学性能等引起了科学界越来越广泛的关注.本文采用DIGIMAT软件对真空浸渗热压成型试验系统工艺(VIHPS)制备的GO-CF/EP复合材料建立代表性体积单元(RVE),然后再利用ANSYS软件构建GO-CF/EP三点弯曲有限元RVE模型,并结合有限元仿真与试验结果来验证该模型的有效性,最后探究石墨烯(GO)含量对GO-CF/EP复合材料弯曲性能的影响.其中通过ANSYS仿真模拟得到的应力云图和弯曲强度数值,表明GO-CF/EP复合材料的微观组分比例会影响宏材料观力学性能,GO含量从0.00％增至0.50％,GO-CF/EP复合材料的弯曲强度提高了 54.26％.再结合试验结果进行对比,发现通过ANSYS软件对GO-CF/EP复合材料的弯曲强度进行模拟得到的值较为准确,其中试验结果与软件模拟结果误差小于10％.因此ANSYS仿真结果可以用来预测GO-CF/EP复合材料的弯曲性能;此外还可以通过增强CF/基体的界面性能、增强基体的强度并在基体内部形成网状结构来提高GO-CF/EP复合材料的整体结构性能.     

混凝土小型空心砌块墙抗震性能的试验研究

进行了１０榀混凝土小型空心砌块墙的反复荷载试验，分析了这类墙体的受剪承载力、刚度、变形性能和耗能能力，并提出了混凝土小型空心砌块墙的受剪承载力计算公式，该公式的计算值较好地符合试验结果     

农技高师图书馆藏书结构的改革与建设

详细总结与论证了作为河北农业技术师范学院办学支柱之一的图书馆的藏书结构１０余年的改革与建设过程；总结和论证了农技高师图书馆藏书建设工作所要掌握的五项基本原则及其执行过程；总结和论证了河北农业技术师范学院图书馆藏书形成的四级结构模式及其利用情况     

辽宁二道沟矿床成矿物理化学条件探讨

通过对流体包裹体的研究，证实了二道沟金矿床的成矿流体盐度为０．８～１０．０ｗｔ％ＮａＣｌ；成矿温度和压力分别为２３０～２９０℃和１×１０７～２×１０７Ｐａ；成矿热液为弱酸性到弱碱性，且具有从早到晚向酸性程度降低方向演化的趋势；ｆＯ２＝３．９９９×１０－４０～１．２０２×１０－２９，ｆＳ２＝１．７４４×１０－１１～３．２５×１０－９；矿化发生在近地表的开放性裂隙系统内，为典型的浅成低温热液矿床     

Subtypes of medulloblastoma have distinct developmental origins

Medulloblastoma encompasses a collection of clinically and molecularly diverse tumour subtypes that together comprise the most common malignant childhood brain tumour. These tumours are thought to arise within the cerebellum, with approximately 25% originating from granule neuron precursor cells (GNPCs) after aberrant activation of the Sonic Hedgehog pathway (hereafter, SHH subtype). The pathological processes that drive heterogeneity among the other medulloblastoma subtypes are not known, hindering the development of much needed new therapies. Here we provide evidence that a discrete subtype of medulloblastoma that contains activating mutations in the WNT pathway effector CTNNB1 (hereafter, WNT subtype) arises outside the cerebellum from cells of the dorsal brainstem. We found that genes marking human WNT-subtype medulloblastomas are more frequently expressed in the lower rhombic lip (LRL) and embryonic dorsal brainstem than in the upper rhombic lip (URL) and developing cerebellum. Magnetic resonance imaging (MRI) and intra-operative reports showed that human WNT-subtype tumours infiltrate the dorsal brainstem, whereas SHH-subtype tumours are located within the cerebellar hemispheres. Activating mutations in Ctnnb1 had little impact on progenitor cell populations in the cerebellum, but caused the abnormal accumulation of cells on the embryonic dorsal brainstem which included aberrantly proliferating Zic1(+) precursor cells. These lesions persisted in all mutant adult mice; moreover, in 15% of cases in which Tp53 was concurrently deleted, they progressed to form medulloblastomas that recapitulated the anatomy and gene expression profiles of human WNT-subtype medulloblastoma. We provide the first evidence, to our knowledge, that subtypes of medulloblastoma have distinct cellular origins. Our data provide an explanation for the marked molecular and clinical differences between SHH- and WNT-subtype medulloblastomas and have profound implications for future research and treatment of this important childhood cancer.     

临南洼陷油气藏分布特征与油气富集主控因素分析

临南洼陷具有良好的油气资源潜力,但随着油气勘探的逐渐深入,临南洼陷的勘探难度越来越大.为了更好的指导今后的油气勘探工作,在研究临南洼陷油气藏基本特征的基础上,从烃源岩、储集层、构造特征等多方面入手,总结油气藏分布特征和规律,分析油气富集成藏的主控因素,剖析各要素对油气富集的影响.结果表明,临南洼陷油气藏类型丰富,主要为断块油气藏及与断层有关的复合油气藏,油气藏主要分布在馆陶组、沙二段和沙三段.临南洼陷油气藏平面上主要分布在临商断裂、夏口断裂及其伴生构造带上,呈环状分布;浊积扇、冲积扇及河流沉积是油气藏分布的主要沉积类型;其富集主要受烃源岩、沉积相、断层等因素控制.油气藏受烃源岩控制围绕生油洼陷展布;有利沉积相带在平面上连续展布,纵向上叠置连片,具有良好的储集条件;断层作为油气的运移通道控制油气的运移,并与地层产状、构造等相配合形成圈闭,控制油气的聚集.