我国高速铁路夜间行车组织方法

为更好地满足旅客出行和企业运营管理的需求,针对我国高速铁路在网络化运营模式下具备夜间行车条件的实际情况,系统地分析了等线、转线、一线维修一线行车和基于客流规律的周期性夜间行车组织方法的技术条件、组织特征、适用条件和与综合维修天窗的协调方法.在夜间高速列车运行距离长、综合维修天窗时间短时优先采用等线行车组织方法,综合维修天窗时间较长时优先采用转线组织方法,基于客流规律周期性地组织夜间列车运行和设置综合维修天窗既能满足维修作业需求,又能在夜间客流需求较大时为夜间高速列车运行创造条件.

定向凝固Al-La合金组织性能的研究

采用Bridgman定向凝固方法,制备出不同抽拉速度下尺寸分别为Φ6mm×50mm和Φ3mm×50mm的试样棒。对试样组织形貌进行分析,发现了一种由α-Al(暗相)和Al11La3(亮相)两相交替出现的枝晶组织,沿枝晶主干方向成分呈周期性变化,称这种组织为周期性双相枝晶组织;而且这种枝晶组织主干方向与凝固方向一致,证明这种枝晶确实存在。通过分析认为,对流可能是产生这种组织的主要原因。经力学性能测试,试样的压缩性能较好,硬度较高。

具有可用性改善的P-Grid覆盖网络

原P-Grid覆盖网络通过大量冗余将低在线率的节点构建成高可用性的系统.考虑分布式环境下节点不一定具有低在线率而呈现周期性,提出一种基于P-Grid的具有可用性改善的节点周期性组织方式.分类节点为长期节点、周期节点和普通节点,将长期节点按原P-Grid方式形成周期性组织下的主体二叉树,设计适当的信息表结构建立节点间的关系,并给出相应的查找、节点加入和数据对象创建的算法.数值分析和模拟实验表明在相同的节点规模及树高度下,周期性组织方式可以达到更高的可用性,同时数值分析也表明不影响维护消耗.

超快激光在玻璃内部直写纳米晶及其应用

超快激光直写技术由于其灵活性、高效性和良好的方向性,可以三维选择性地在材料内部进行加工,被广泛应用于玻璃的微晶化及其器件的制备中,在光储存、波导激光器、光子电路和集成光子芯片等领域有着广泛的应用前景。本文简要概述了超快激光在玻璃内部诱导析晶的原理,晶态/非晶态自组织周期性结构的形成机制,以及超快激光在玻璃三维空间中诱导析晶的最新研究进展,总结了通过控制激光参数和玻璃成分等实现对结晶形态、结构及光学性质调控的相关研究,并对所直写的微纳结构在非线性器件、光储存、激光器等领域的应用和发展方向进行了概述与展望。

Effect of Zn addition on microstructure and mechanical properties of cast Mg-Gd-Y-Zr alloys

The effects of Zn addition on the microstructure and mechanical properties of Mg.10Gd.3Y.0.6Zr(wt.%)alloys in the as-cast,solution-treated,and peak-aged conditions were investigated.Experimental results reveal that the microstructure of the as-cast alloy without Zn consists ofα-Mg and Mg24(Gd,Y)5 phases,and the alloy with 0.5 wt.%Zn consists ofα-Mg,(Mg,Zn)3(Gd,Y)and Mg24(Gd,Y,Zn)5 phases.With the addition of Zn increasing to 1 wt.%,the Mg24(Gd,Y,Zn)5 phase disappears and some needle-like stacking faults distribute along the grain boundaries.Moreover,the 18R long-period stacking ordered(LPSO)phase is observed in the as-cast alloy with 2 wt.%Zn.After solution treatment,the Mg24(Gd,Y)5 and Mg24(Gd,Y,Zn)5 eutectic phases are completely dissolved,and the(Mg,Zn)3(Gd,Y)phase,needle-like stacking faults and 18R LPSO phase all transform into 14H LPSO phase.Both the suitable volume fraction of 14H LPSO phases and the fine ellipsoidal-shapedβ′phases make the peak-aged alloy with 0.5 wt.%Zn exhibit excellent comprehensive mechanical properties and the UTS,YS and elongation are 338 MPa,201 MPa and 6.8%,respectively.

Effect of long period stacking ordered phase on damping capacities of as-cast Mg-Zn-Y alloys

The microstructure and damping capacities of MgZnxYi.33x(x=l-4at.%)alloys were discussed and researched.The main phase composition of the alloys consists of a_Mg and long-period stacking ordered(LPSO)phase.Due to increasedLPSO phase,grain size was refined.LPSO phase was advantageous to the damping properties of the Mg-Zn-Y alloys.Mg-7%Zn-12.8%Y has the highest damping capacity up to0.04.Due to stacking fault probability,the LPSO phase in the Mg-Zn-Yalloys could be new damping source to dissipate energy so as to contribute to the improvement of damping capacities.

The significance of cyclin B1 expression in colorectal cancers

Objective: To study the relationship between the expression of human cyclin B1 in colorectal carcinomas and the pathological characters. Methods: The Expression of cyclin B1 in 66 cases of colorectal carcinomas were detected by flow cytometry and immunohistochemistry. Then the relationship between the expression of cyclin B1 in colorectal carcinomas and pathological characters was analyzed with statistics. Results: The expression of cyclin B1 in colorectal carcinomas had associa- tivity with the cancer cell differentiation (P<0.05); However, the expression of cyclin B1 in colorectal carcinomas had no obvious associativity with cancer cell infiltrate depth and lymph nodes metastasis (P>0.05). Conclusion: In the colorectal cancers with high expression of cyclin B1, the cancer cells would present high differentiation; with low expression of cyclin B1 the cancer cells would present low differentiation. Along with the expression of cyclin B1 from high to low, the cancer cells differentiation has the tendency from high to low too.

超声诊断乳腺增生误区及乳腺增生期超声表现

超声诊断(ultrasonic diagnosis)是将超声检测技术应用于人体,通过测量了解生理或组织结构的数据和形态,发现疾病,作出提示的一种诊断方法。超声诊断是一种无创、无痛、方便、直观的有效检查手段,尤其是B超,应用广泛,影响很大,与X射线、CT、磁共振成像并称为4大医学影像技术。在医学中病情诊断的准确与否关系着病情能否得到良好控制,在很大程度上关系到患者的生命安全、经济耗费。近年来超声医师诊断乳腺增生的病例颇多,而对于如何才算乳腺增生存在较大主观意愿,缺乏统一客观标准。增生病变组织形态学改变复杂多样,命名繁多,病理分型中的小叶增生超声诊断主观性最大。在月经周期中乳腺小叶有不同的变化,我们可以简单分成了增殖期和月经期。增殖期乳腺小叶逐渐扩大,腺泡增生肥大。月经期导管系统逐渐减少,周期第28天上皮细胞凋亡数达最多。乳腺增殖期超声图像和乳腺增生图像是否存在明显区别,是否我们存在把增殖期乳腺报成乳腺增生?了解到乳腺周期性组织学变化对我们是否诊断乳腺增生有重要意义。