二氧化钒薄膜的低温制备及其性能研究

针对VO₂薄膜在微测辐射热计上的应用，采用射频反应溅射法，在室温下制备氧化钒薄膜；研究了氧分压对薄膜沉积速率、电学性质及成分的影响.通过调节氧分压，先获得成分接近VO₂的非晶化薄膜，再在400℃空气中氧化退火，便可制得高电阻温度系数，低电阻率的VO₂薄膜，电阻温度系数约为-4%/℃，薄膜方块电阻为R_□为100—300kΩ；薄膜在室温下沉积，400℃下退火的制备方法与微机电加工(micro electromechanic 关键词： 二氧化钒 电阻温度系数 氧分压 射频反应溅射法     

氢离子对血红蛋白-氧亲和力影响的拉曼光谱研究

静脉采血,分离并制备血红蛋白溶液,用拉曼光谱方法观察不同pH时H+对血红蛋白-氧结合状态与能力的影响。结果显示:在514.5nm激光的激发下,当pH为7.4时,随着氧分压降低,血红蛋白在1 375,1 562,1 585和1 638cm-1峰强均逐渐减弱,其中以1 375和1 638cm-1峰渐变最明显且相关性显著。以氧分压为横坐标,拉曼峰强为纵坐标,对pH为5.7,7.4和8.0时的血红蛋白在1 375和1 638cm-1峰的强度及其氧分压进行线性拟合,结果显示2处的拟合效果均良好,拉曼峰强度/氧分压的斜率关系表现为K8.0>K7.4>K5.7,表明pH越低血红蛋白的氧亲和力越低,越有利于向组织释放氧气。研究表明,应用拉曼光谱技术可检测血红蛋白与氧的亲和力,通过对血红蛋白-氧亲和力的量化检测,可以观察pH对血氧结合状态的影响,为血氧分压的监测以及氢离子和二氧化碳等血氧亲和力调节因子调节能力的研究提供新的研究方法与理论基础。     

氧分压对固体氧化物电解池性能的影响

High-temperature (700–900 ℃) steam electrolysis based on solid oxide electrolysis cells (SOECs) is valuable as an efficient and clean path for large-scale hydrogen production with nearly zero carbon emissions, compared with the traditional paths of steam methane reforming or coal gasification. The operation parameters, in particular the feeding gas composition and pressure, significantly affect the performance of the electrolysis cell. In this study, a computational fluid dynamics model of an SOEC is built to predict the electrochemical performance of the cell with different sweep gases on the oxygen electrode. Sweep gases with different oxygen partial pressures between 1.01 × 10³ and 1.0 × 10⁵ Pa are fed to the oxygen electrode of the cell, and the influence of the oxygen partial pressure on the chemical equilibrium and kinetic reactions of the SOECs is analyzed. It is shown that the rate of increase of the reversible potential is inversely proportional to the oxygen partial pressure. Regarding the overpotentials caused by the ohmic, activation, and concentration polarization, the results vary with the reversible potential. The Ohmic overpotential is constant under different operating conditions. The activation and concentration overpotentials at the hydrogen electrode are also steady over the entire oxygen partial pressure range. The oxygen partial pressure has the largest effect on the activation and concentration overpotentials on the oxygen electrode side, both of which decrease sharply with increasing oxygen partial pressure. Owing to the combined effects of the reversible potential and polarization overpotentials, the total electrolysis voltage is nonlinear. At low current density, the electrolysis cell shows better performance at low oxygen partial pressure, whereas the performance improves with increasing oxygen partial pressure at high current density. Thus, at low current density, the best sweep gas should be an oxygen-deficient gas such as nitrogen, CO₂, or steam. Steam is the most promising because it is easy to separate the steam from the by-product oxygen in the tail gas, provided that the oxygen electrode is humidity-tolerant. However, at high current density, it is best to use pure oxygen as the sweep gas to reduce the electric energy consumption in the steam electrolysis process. The effects of the oxygen partial pressure on the power density and coefficient of performance of the SOEC are also discussed. At low current density, the electrical power demand is constant, and the efficiency decreases with growing oxygen partial pressure, whereas at high current density, the electrical power demand drops, and the efficiency increases.     

沉积速率和氧分压对HfO2薄膜残余应力的影响

采用ZYGO MarkIII-GPI数字波面干涉仪对以K9玻璃为基底的电子束蒸发方法制备的HfO₂薄膜中的残余应力进行了研究,讨论了沉积速率、氧分压这两种工艺参量对HfO₂薄膜残余应力的影响.实验结果表明：在所有的工艺条件下,薄膜的残余应力均为张应力;随着沉积速率的升高,氧分压的减小,薄膜的堆积密度逐渐增大,而残余应力呈减小趋势.同时用X射线衍射技术测量分析了不同工艺条件下HfO₂薄膜的晶体结构,探讨了HfO₂薄膜晶体 关键词： 残余应力 2薄膜')" href="#">HfO₂薄膜 沉积速率 氧分压     

氧分压对Ni/HfO_x/TiN阻变存储单元阻变特性的影响

采用射频磁控溅射的方法,基于不同氧分压制备的氧化铪构建了Ni/HfO_x/TiN结构阻变存储单元.研究发现,随着氧分压的增加,薄膜表面粗糙度略有降低;另一方面,阻变单元功耗降低,循环耐受性能可达10~3次,且转变电压分布的一致性得到改善.结合电流-电压曲线线性拟合结果及外加温度测试探究了器件的转变机理,得出在低阻态的传导机理为欧姆传导机理,在高阻态的传导机理为肖特基发射机理,并根据氧空位导电细丝理论,对高低阻态的阻变机理进行了详细的理论分析.     

新型快速显微多道分光光度技术对血红蛋白的光谱分析

用新型快速显微多道分光光度(MMSP)技术,在生理环境(pH、温度、氧分压和渗透压)改变下,对单个活态人血红细胞内血红蛋白分子的吸收光谱进行监测。发现生理环境的改变,引起血红蛋白吸收光谱曲线540,575 nm特征吸收峰的峰高、峰位和峰形发生了不同程度的变化。MMSP技术提示血红蛋白分子的结构、浓度和功能与上述生理环境密切相关。     

加压下煤的着火特性的研究 Ⅰ.着火特性的影响因素

采用带程序升温控制的、可在加压下测定煤着火特性的装置,在程序升温速度(7.5℃/min)和加压条件下,测定了影响煤和煤焦着火特性(着火温度与燃烧时间)的各种因素,这些因素包括煤的粒度、试样质量、空气流量、系统压力和氧分压等。试验表明,这些因素的影响与煤中挥发份有一定的关系,着火温度和燃烧时间随总压或氧分压增加而下降。     

高温热处理气氛对低氟MOD法制备YBCO超导薄膜的影响研究

金属有机物沉积法(MOD)制备YBa2Cu3O7-x(YBCO)涂层导体是最具有商业前景的方法之一.本文使用环烷酸铜代替三氟乙酸铜,降低了前驱液中大约50%的氟含量.然后在带有缓冲层(Y2O3/YSZ/CeO2)的Ni-5at.%W基带上采用MOD法制备了YBCO薄膜并系统研究了高温热处理过程中气体流速和氧分压对YBC...     

携氧/释氧分析仪氧分压和血氧饱和度计量校准方法

为实现半氧饱和度分压的计量溯源性,评价携氧/释氧分析仪的性能,分别建立氧分压和血氧饱和度的计量校准方法。根据国际临床化学和实验室医学联盟文件标准,以去离子水为样品,国家一级标准物质气体为气源建立氧分压参考测量方法。根据美国临床实验室标准协会C46-A2相关文件以及多功能血气分析仪中血氧饱和度示值的计量校准方法,以牛血红蛋白溶液为样品,使用高精度酶标仪建立血氧饱和度测量方法。氧分压相对示值误差分别为-2.82%和-1.35%,变异系数（CV）分别为0.31%和0.74%;血氧饱和度测量数据为（96.83±0.85）%,变异系数为0.88%,携氧/释氧分析仪测量结果为（96.68±0.67）%,变异系数为0.69%。该方法可分别实现氧分压和血氧饱和度的量值溯源,确保测得的P50值的计量溯源性。