细胞色素C551在ITO电极上的直接电化学

在不加任何电子转移促进剂的条件下,用循环伏安法(CV)和微分脉冲伏安法(DPV)观察到细胞色素C551在ITO导电玻璃上的直接电化学行为.结果显示电极反应过程为准可逆性质,计算得到细胞色素C551的扩散系数、式电位和异相电子转移标准速率常数,并对其在ITO导电玻璃电极上的电子转移机制进行了初步分析.     

尿样中克仑特罗免疫亲和色谱-气/质联用检测方法的研究

以单抗为配基制备克仑特罗免疫亲和柱,建立了简单、快速、特异的样品净化技术,柱容量达到100 ng。偶联抗体量与柱容量呈线性关系,线性方程为:y=236.36x 6.6214,R2=0.9461。测定尿样中的克仑特罗,不需前处理直接用亲和柱提纯后以气质联用(GC/MS)方法检测。空白猪尿添加浓度为205、01、00 ng时,回收率分别为85%±1.3,85.9%±1.3,81.5%±2.7。同时以NY/XQ421-2003标准中净化方法为对照,回收率分别为113%±5.6,94.5%±10,78.6%±1.7,偶联非特异抗体的对照组亲和柱对样品保留值为7.03%。数据显示:免疫亲和柱作为提纯方法,与传统固相萃取提纯方法相比平行性好,提纯后样本杂质少。因此免疫亲和柱是净化样品的一个有效方法。     

含参数不等式的一种解法

含有参数的不等式解法是高中数学教学中的一个难点,也是学生学习的一个难点,其困难之处在于分类讨论标准的化分.许多学生不知怎样化分,化分也不准确 ,不全面.本文结合教学实际介绍一种方法--找参数分界点确定分类标准解含有参数的不等式,以期对学生的学习有所帮助.     

TiO2颗粒表面无机包覆的研究进展

从表面处理的作用、过程、方法、种类、机理、影响因素等方面综述了二氧化钛颗粒无机包覆的研究进展,着重阐述了二氧化钛包硅、包铝的原理及工艺条件。     

基于5-氨基乙酰丙酸的SD大鼠结肠组织荧光光谱多变量统计分析方法研究

探讨用多变量统计分析方法对激光诱导的SD大鼠结肠组织5-ALA-PpⅨ荧光光谱进行分类,以诊断结肠早癌。对20只DMH诱导的SD大鼠,12只诱导鼠的第二代鼠,8只正常SD大鼠,按25 mg·kg-1体重剂量尾静脉注射5-ALA,150 min后进行活体激光检测,钛宝石激光器激发波长370 nm。将343条3类组织谱线分为训练组和预测组,经预处理,再采用主成分分析法提取4个主成分变量。利用训练组建立逐步多变量Logistic回归模型,并对预测组预测。3类组织病理类型两两结合,共构建3个回归方程。正常组织与早癌及进展期癌识别的特异性分别为100%, 98.4%,敏感性分别为96%, 100%,准确率分别为98%, 99.2%。在光敏剂5-ALA的辅助作用下,对370 nm激光诱导的结肠组织荧光光谱,采用主成分变量压缩与逐步多变量Logistic回归分析方法相结合,可以获得较高的正常组织对早癌及进展期癌组织识别特异性和敏感性,是一种较有潜力的结肠早癌无损诊断方法。     

A novel structure of a high current gain 4H-SiC BJT with a buried layer in base

In this paper, a new structure of a 4H-SiC bipolar junction transistor (BJT) with a buried layer (BL) in the base is presented. The current gain shows an approximately 100% increase compared with that of the conventional structure. This is attributed to the creation of a built-in electric field for the minority carriers to transport in the base which is explained based on 2D device simulations. The optimized design of the buried layer region is also considered by numeric simulations.     

轧带的润滑力学分析

本文耦合了流体动力润滑理论,经典轧制理论及弹性接触变形理论,并计入了润滑油的压粘效应和轧制材料的硬化效应等因素,运用有限元法和边界元法等计算方法,分别得到了刚性轧辊下的理论解、弹性轧辊下的Boussinesq解及边界元解,预示了轧带工作区的压力、剪应力以及膜厚的分布规律,确定了最小油膜厚度,并对计算结果与实验结果进行了比较。     

马尔可夫链在冗余系统可靠度求解中的应用

求解了单支光纤陀螺失效率取不同值时系统可靠度随时间的变化曲线,并分析了冗余系统可靠度曲线的意义,为光纤陀螺惯性测量冗余系统的可靠性研究提供了重要的信息,并为冗余系统的费效比计算提供了可信的依据。对组成系统的器件进行冗余是提高系统可靠性的一种常用方法,定量研究复杂冗余系统的冗余关系和求解系统的可靠度是极其困难的,马尔可夫模型是一种有效的方法。分析和确定了一个复杂的光纤陀螺惯性测量冗余系统的冗余关系,介绍了马尔可夫模型的基本原理,讨论了冗余系统应用马尔可夫模型的条件,应用马尔可夫模型建立了冗余系统的状态转移图和状态转移矩阵,最后给出了冗余系统可靠度的解析表达式,定量求解了冗余系统的可靠度。     

A novel high performance TFS SJ IGBT with a buried oxide layer

A novel high performance trench field stop(TFS) superjunction(SJ) insulated gate bipolar transistor(IGBT) with a buried oxide(BO) layer is proposed in this paper. The BO layer inserted between the P-base and the SJ drift region acts as a barrier layer for the hole-carrier in the drift region. Therefore, conduction modulation in the emitter side of the SJ drift region is enhanced significantly and the carrier distribution in the drift region is optimized for the proposed structure. As a result, compared with the conventional TFS SJ IGBT(Conv-SJ), the proposed BO-SJ IGBT structure possesses a drastically reduced on-state voltage drop(Vce(on)) and an improved tradeoff between Vce(on)and turn-off loss(Eoff), with no breakdown voltage(BV) degraded. The results show that with the spacing between the gate and the BO layer Wo = 0.2 μm, the thickness of the BO layer Lo = 0.2 μm, the thickness of the drift region Ld = 90 μm, the half width and doping concentration of the N- and P-pillars Wn = Wp = 2.5 μm and Nn = Np = 3 × 1015cm-3, the Vce(on)and Eoffof the proposed structure are 1.08 V and 2.81 mJ/cm2with the collector doping concentration Nc = 1×1018cm-3and 1.12 V and1.73 mJ/cm2with Nc = 5 × 1017cm-3, respectively. However, with the same device parameters, the Vce(on)and Eofffor the Conv-SJ are 1.81 V and 2.88 mJ/cm2with Nc = 1 × 1018cm-3and 1.98 V and 2.82 mJ/cm2with Nc = 5 × 1017cm-3,respectively. Meanwhile, the BV of the proposed structure and Conv-SJ are 1414 V and 1413 V, respectively.     

A low specific on-resistance SOI LDMOS with a novel junction field plate

A low specific on-resistance SO1 LDMOS with a novel junction field plate （JFP） is proposed and investigated theo- retically. The most significant feature of the JFP LDMOS is a PP-N junction field plate instead of a metal field plate. The unique structure not only yields charge compensation between the JFP and the drift region, but also modulates the surface electric field. In addition, a trench gate extends to the buffed oxide layer （BOX） and thus widens the vertical conduction area. As a result, the breakdown voltage （BV） is improved and the specific on-resistance （Ron,sp） is decreased significantly. It is demonstrated that the BV of 306 V and the Ron,sp of 7.43 mΩ.cm2 are obtained for the JFP LDMOS. Compared with those of the conventional LDMOS with the same dimensional parameters, the BV is improved by 34.8%, and the Ron,sp is decreased by 56.6% simultaneously. The proposed JFP LDMOS exhibits significant superiority in terms of the trade-off between BV and Ron,sp. The novel JFP technique offers an alternative technique to achieve high blocking voltage and large current capacity for power devices.