PTC－BaTiO_3射频溅射用靶材的制备

研究了用于射频溅射ＰＴＣ－ＢａＴｉＯ_３薄膜的厚大靶材制备工艺，所制成的靶材的室温电阻率为８００Ω·ｃｍ，ＰＴＣ效应＞１０５，平均粒径为１～３μｍ，讨论了配方中ＴｉＯ_２品种的选择、施受主添加剂的搭配与掺量以及烧成中的升降温速率对于ＰＴＣ效应的影响     

TiO_2对ZrO_2－NiCr金属陶瓷烧结特性和相稳定性的影响

本文研究了ＴｉＯ２掺入对ＣａＯ稳定ＺｒＯ２（简称ＣａＳＺ－ＮｉＣｒ）金属陶瓷烧结特性的影响，测定了ＣａＳＺ－ＮｉＣｒ－ＴｉＯ２金属陶瓷烧结样品的密度和显微硬度，结果表明，ＴｉＯ２的掺入能提高ＣａＳＺ－ＮＩＣｒ金属陶瓷的烧结密度和显微硬度，对ＣａＳＺ－ＮｉＣｒ金属陶瓷有助烧结作用．金相观察表明，ＴｉＯ３的掺入改变了ＮｉＣｒ相在金属陶瓷中的形貌，说明了ＮｉＣｒ与ＣａＳＺ的浸润性有一定的改善．ＸＲＤ和ＥＰＭＡ分析结果显示，ＴｉＯ２偏聚在ＮｉＣｒ金属相中，不影响ＣａＳＺ的稳定性．     

抑制剂对纳米WC-10Co复合粉末烧结性能的影响

以液相复合-连续还原碳化方法制备的纳米WC-10Co(以质量计)复合粉末为原料,选择VC和Cr3C2作为超细WC-10Co硬质合金晶粒生长抑制剂,研究晶粒生长抑制剂加入量对超细WC-10Co硬质合金组织、晶粒和性能的影响。实验结果表明：超细WC-10Co硬质合金中WC晶粒度随着晶粒生长抑制剂加入量的增加而减小,纳米WC-10Co复合粉中加入0．4％VC和0．4％Cr3C2(以质量计)晶粒生长抑制剂,经1380℃真空烧结60min,1320℃低压处理30min后,可以得到平均晶粒度380nm、断裂强度3．55 GPa和Rockwell A硬度92．6综合性能较好的超细WC-10Co硬质合金。过多添加晶粒生长抑制剂反而降低了超细WC-10Co硬质合金的性能。     

颈动脉支架成形术后颅内出血临床分析

【摘要】 目的 探讨颈动脉支架成形术（CAS）后颅内出血的临床特点、发生机制及治疗。方法 回顾性分析2008年1月至2017年1月收治的颈动脉狭窄行CAS术患者,记录并分析术后出血患者临床及影像学资料。结果 513例患者中5例（0.97%）发生颅内出血,均经术后头颅CT/DSA证实。其中男3例,女2例,平均年龄（71.4±5.0）岁;颈动脉狭窄率为90%～99%,出血时间为术中即刻至术后10 d;1例DSA显示同侧基底节区烟雾血管,1例DSA发现穿支动脉出血。3例接受药物保守治疗,其中1例恢复良好,2例死亡;2例接受血肿穿刺引流,遗留偏瘫。结论 CAS术后颅内出血发生率较低,但致死、致残率较高。发病原因较多,术前充分评估、危险因素筛选可降低发生率。出血后积极控制血压,予以镇静、停用抗凝药、减少/停用抗血小板药以及手术干预,可提高患者生存率。
     

插值二分树描述的二值图象邻域寻找的搜索算法

通过分析插值二分树编码方法，归纳出了图象的插值二分码的若干性质，在此基础上提出了图象二分块相邻的充要条件，并给出了相应的寻找图象块邻域的算法。该算法仅对图象二分块的坐标进行简单运算及判别，便于计算机实现     

Research on rare earth and iron-rich diamond-enhanced tungsten carbide composite button

At the present time in china, the binder used in tungsten carbide composite button is mainly cobalt, which is very expensive. In order to solve the problems, a new type of rare earth and iron-rich diamond-enhanced tungsten carbide with high abrasive resistance and high toughness against impact, which realizes to substitute ferrum for cobalt, has been developed. The key problems in making the button are to improve the mechanical properties of matrix and increase the welding strength between the diamond and the matrix. All these problems have been solved effectively by low temperature activation hot-press sintering, doping rare earth lanthanum in matrix and high sintering pressure. The properties of the button have been determined under laboratory conditions. The test results show that its hardness is more than 90 HRA, its abrasive resistance is 39 times more than that of conventional cemented tungsten carbide, and its toughness against impact is more than 200 J. All these data show the button has very good mechanical properties.     

Ce掺杂SrMgF4超结构多晶体的吸收/光致发光光谱

稀土(RE)离子掺杂的钙钛矿型氟化物是可调谐光学材料的候选材料。本工作通过沉淀法合成了SrMgF₄: xCe (x = 0, 0.007, 0.013和0.035)粉末。X射线衍射(XRD)分析表明所获得的荧光粉具有单斜超结构, 价态分析证实存在Ce³⁺/Ce⁴⁺混合价, 在紫外光区通过不同波长的激发光观察到两个荧光带B和C。当Ce³⁺多面体的对称性从高对称变为低对称时, 源于单斜超结构的晶体场导致能级发生强烈的改变。     

一种基于目标边界的不变特征提取方法

提出了一种基于目标边界的不变特征提取方法。导出了用物体角点坐标表示的低阶边界矩的闭合形式,构造了基于边界矩的仿射变换不变量。该方法只需要对物体角点进行简单的代数运算,因此,该方法简单明了,计算量很小。实验结果证明了该方法的有效性。     

Synthesis of multi-walled carbon nanotube-tungsten carbide composites by the reduction and carbonization process

Multi-walled carbon nanotube-tungsten carbide composites were prepared by the reduction and carbonization process using multi-walled carbon nanotubes (MWCNTs) and WO₃ precursor by molecular level mixing and calcination. The pre-prepared MWCNT-tungsten carbide composites were characterized by scanning electron microscope and transmission electron microscope. Furthermore, the crystal phase was identified by X-ray diffraction. The results showed that the one-dimensional (1D) nanostructure of the MWCNTs was destroyed by the direct carbonization reaction between the MWCNTs and the WO₃ precursor without an additional carbon source. Moreover, pure MWCNT-tungsten carbide composites were difficult to obtain. With the additional carbon source CH₄, pure MWCNT-tungsten carbide composites were prepared, and the 1D nanostructure of the MWCNTs was retained.     

粉末冶金TiAl基合金及其力学性能的研究进展

综述了粉末冶金法制备TiAl基合金的几种方法，包括预合金粉末法、元素粉末法、自蔓延高温合成、放电等离子烧结等方法，介绍了采用粉末冶金方法制备TiAl基合金的力学性能的研究，指出当前粉末冶金TiAl基合金制备中存在的问题及研究重点。