沥青基碳/碳复合材料的组织特性

以 １Ｋ ＰＡＮ基碳纤维为增强体、以调制中温煤沥青为基体前躯体,分别在常压下和高压（４０ＭＰａ、８０ＭＰａ）下制备出了沥青基碳／碳复合材料。借助偏光显微镜对碳／碳复合材料试样进行的微观组织的观察发现,碳基体中既有域组织,也有镶嵌组织,而焦炭主要为细镶嵌组织．偏光试样经过酸液氧化腐蚀处理后,利用电子显微镜对其扫描观察,发现各向异性区域呈现出流线组织特征,流线纹路的疏密与沥青碳化时的压力有关．压力越高,纹路越密实,表明碳层面的取向性也就越好．     

微旋管状碳纤维的微细构造和表面特性

采用ＣＶＤ法合成了结构类似于ＤＮＡ的高功能微旋管状碳纤维。考察了其微观形态、微细构造、,并研究其表面特性。微旋管状碳纤维和ＶＧＣＦ的成长机理完全不同,因此微细结构也完全不同。组成旋管的纤维从表面到芯完全被碳粒所充满,且几乎是非晶质的,该纤维的表面活性比勘察碳纤维高得多。     

风力发电系统变浆距模糊自适应PID控制器仿真与研究

为解决普通PID对风力发电机输出功率控制不稳定的问题。针对整个风力发电系统的非线性特点提出了模糊自适应PID变桨距控制的方案。以输出功率值与额定功率值的偏差以及偏差的变化率作为模糊控制的输入,把模糊推理出的三个整定参数和初始PID参数进行叠加后控制变桨距,最后在Matlab/Simulink上搭建整体模型并仿真得到输出功率波形。结果表明:模糊自适应PID比普通PID能更好提高输出功率的稳定性。     

Tailor‐Made Designer Helical Peptides that Induce Mitochondrion‐Mediated Cell Death without Necrosis

Managing protein–protein interactions is essential for resolving unknown biological events at the molecular level and developing drugs. We have designed and synthesized a side‐chain‐crosslinked helical peptides based on the binding domain of a pro‐apoptotic protein (Bad) that induces programed cell death. The peptide showed high helical content and bound to its target, Bcl‐X_L, more strongly than its non‐crosslinked counterparts. When HeLa cells were incubated with the crosslinked peptide, the peptide entered the cytosol across the plasma membrane. The peptide formed a stable complex with Bcl‐X_L localized at the outer mitochondrial membrane, and this binding event caused the release of cytochrome c from the intermembrane space of mitochondria into the cytosol. This activated the caspase cascade: 70 % of HeLa cells died by the apoptosis pathway (without evidence of necrosis).     

Cubic helical splines with Frenet-frame continuity

We present a scheme of interpolating a sequence of points p₀,…,pn in R³ by a piecewise-cubic-helical spline with continuous Frenet frame. Each cubic helical segment rk(ξ) connecting pk−1 and pk is constructed such that its end tangents are symmetric with respect to the displacement vector Δpk=pk−pk−1. The existence condition of such a segment rk(ξ) is formulated in terms of the configuration involving Δpk and the Frenet frame of rk(ξ) at pk−1. A Frenet-frame-continuous spline is obtained by matching the Frenet frames of sequentially constructed segments at their juncture points.     

双耳差频声对纯音音高差别阈限的影响

分别选择Beta脑波和Theta脑波频域范围内的双耳差频声作为声音刺激.纯音音高差别阈限的测量选择恒定刺激法,标准刺激选取250 Hz,1 000 Hz,4 000 Hz,分别测量声音刺激前后被试的音高差别阈限,比较两种不同声音刺激对差别阈限的影响.实验结果表明,经6 Hz的双耳差频声刺激后,三个频点的音高差别阈限分别降低了32.31％,42.86％,15.25％.经16 Hz的双耳差频声刺激后,三个频点的音高差别阈限分别降低了17.91％,21.31％,12.07％.     

Study of oxidization of coal–pitch by O_3

For the purpose of obtaining small molecular and oxygen-containing aromatic compounds,taking a toluene-extracted coal pitch as the research object,the oxidation of coal–pitch by ozone(O_3) in formic acid was studied.The coal–pitch sample and the oxidized pitch residue were characterized by elementary analysis and Fourier transform infrared spectroscopy(FTIR),while the small molecular products were analyzed by a gas chromatography–mass spectrometer(GC–MS).The results show that the highest oxygen content of oxidized coal pitch had been acquired at a reaction temperature of 50 °C,an O_3 flow rate of6300 mg/h and a reaction time of 4 h.Quite a lot of hydroxyls and carbonyls were introduced into the structure of the oxidized coal–pitch,while the small molecules produced mainly involve nonpolar aromatic compounds,aromatic anhydride and quinone compounds.It is speculated that the mechanism is direct electrophilic oxidation in which the molecules of O_3 directly attack the aromatic ring at its carbon atoms with high electron density,and then generate hydroxyl or carbonyl until the aromatic ring cracks.This study shows that O_3 can make the fused aromatic ring of coal–pitch become oxidized and depolymerized,and hence the ozonization of coal–pitch can be a potential method for obtaining oxygencontaining aromatic compounds.     

油套管螺纹关键参数的三坐标测量方法

螺纹参数的精确测量对油套管接头的设计开发和加工制造有重要作用。为了对螺纹关键参数进行精确测量,研发了油套管螺纹中径和螺距的测量方法。建立了测量空间坐标系,在每个螺纹牙侧面进行两处采点测量,给出了测点的直线方程,结合直线间距离算法,得到了螺纹中径线与螺纹牙的交点,利用最小二乘法对交点数据进行拟合,建立了交点与螺纹中径线的几何关系及其数学模型,推导出了中径和螺距的计算公式。以油管螺纹接头为例进行了螺纹中径及螺距的测量试验和应用,并将测量值和实际值进行了对比。对比结果表明,各螺纹牙中径和螺距测量精度高,误差不超过1%。该三坐标测量方法的提出为未知理论螺距和牙型角的螺纹测量提供了新方法。     

带回油线唇形密封的反向泵送机制研究与实验验证

以某种带回油线的唇形密封作为研究对象,通过有限元软件建立油封的仿真计算模型。该模型耦合考虑唇封与轴之间的接触力学分析和润滑油膜的三维流场分析。在计算中,通过调整油膜厚度和唇口轮廓使流体压力与接触压力达到平衡从而实现流固耦合。通过仿真计算得到唇封的接触宽度、径向力和反向泵送率等参数。通过台架实验测得无压差条件下的泄漏量并与理论计算结果进行对比,验证了模型的准确性。基于该模型对无压差和有压差2种工况下的静态接触特性与动态流场进行分析,探讨带回油线唇形密封的工作机制。该理论模型计算效率高,且在较大转速范围内保证了良好的精度,可以应用到其他流体动压油封的开发设计上,具有很好的工程价值。     

插编钢缆吊索及制造设备

为解决φ250 mm以上钢丝绳缆的制作及将绳缆高效率制成高质量的插编钢缆吊索难题,研制一种φ400mm缆绳编织机和φ400 mm退捻插编机。介绍插编钢缆吊索制造存在的问题及φ400 mm缆绳编织机的工作原理、结构特点、旋转系统、行走系统和控制系统。给出退捻插编机原理及机构示意图。利用φ400 mm缆绳编织机和退捻插编机可生产出最大直径450 mm、质量60 t的插编钢缆吊索,生产效率大大提高。