Investigation of current transport parameters of Ti/4H-SiC MPS diode with inhomogeneous barrier

The current transport parameters of 4H-SiC merged PiN Schottky(MPS) diode are investigated in a temperature range of 300-520 K.Evaluation of the experimental current-voltage(I-V) data reveals the decrease in Schottky barrier height Φ b but an increase in ideality factor n,with temperature decreasing,which suggests the presence of an inhomogeneous Schottky barrier.The current transport behaviours are analysed in detail using the Tung’s model and the effective area of the low barrier patches is extracted.It is found that small low barrier patches,making only 4.3% of the total contact,may significantly influence the device electrical characteristics due to the fact that a barrier height of 0.968 eV is much lower than the average barrier height 1.39 eV.This shows that ion implantation in the Schottky contact region of MPS structure may result in a poor Ti/4H-SiC interface quality.In addition,the temperature dependence of the specific on-resistance(R on sp),T 2.14,is determined between 300 K and 520 K,which is similar to that predicted by a reduction in electron mobility.     

血红蛋白与NO分子间相互作用的电化学表征

近年来 ,蛋白质的电化学研究引起了人们广泛兴趣[1～ 5] .利用自组装技术[4 ] 或将蛋白质分子固定于双层磷脂膜、水凝胶、表面活性剂膜及 Al2 O3膜上[6～ 9] 等可成为制备蛋白质膜的有效手段 .血红蛋白(Mr=6 50 0 0 )是生物体内一类重要的蛋白 ,由于对其结构已有较清楚的认识 [10 ] ,因而常被选作探讨生物大分子的电化学行为的模型分子 . NO是一种内皮细胞松弛因子、神经递质和免疫系统的媒介体 ,与生物体内的许多生理过程、疾病的产生与治疗有密切关系 [11～ 13] .因此研究蛋白与 NO之间的相互作用并寻求监测 NO的各种途径具有重要意义…     

Iterative algorithms for solving some tensor equations

We propose a class of iterative algorithms to solve some tensor equations via Einstein product. These algorithms use tensor computations with no matricizations involved. For any (special) initial tensor, a solution (the minimal Frobenius norm solution) of related problems can be obtained within finite iteration steps in the absence of roundoff errors. Numerical examples are provided to confirm the theoretical results, which demonstrate that this kind of iterative methods are effective and feasible for solving some tensor equations.     

5,6-Didehydroginsenosides from the roots of Panax notoginseng

Two minor novel dammarane-type saponins - 5,6-didehydroginsenoside Rd (1) and 5,6-didehydroginsenoside Rb1 (2) - were isolated from the dried roots of Panax notoginseng along with sixteen known saponins. The structures of the new compounds were elucidated on the basis of spectroscopic and chemical methods.     

Meloslines A and B,two novel indole alkaloids from Alstonia scholaris

An unprecedented indole alkaloid melosline A (1), with 6/5/6/6 tetracyclic ring skeleton, together with a new alkaloid melosline B (2) and one known compound (3) were isolated from the leaves and twigs of Alstonia scholaris. The new structures were elucidated by comprehensive spectroscopic analysis. The absolute configuration of compound 1 was confirmed by comparison of experimental data with calculated electronic circular dichroism (ECD). Compound 1 exhibited moderate cytotoxicity against MCF-7 cancer cell lines.     

基于萘酰亚胺的生物硫醇探针的合成及对含硫醇氨基酸的检测

合成了以4-羟基萘酰亚胺为荧光团,2,4-二硝基苯磺酰氧基为特异性识别基团的生物硫醇探针4-(2,4-二硝基苯磺酰氧基)-正丁基-1,8-萘酰亚胺(DNSBN).吸收光谱和荧光光谱结果表明, DNSBN对半胱氨酸(Cys)、同型半胱氨酸(Hcy)和谷胱甘肽(GSH)3种生物硫醇分子具有高效的检测识别能力,不受其它17种天然氨基酸的干扰.同时,通过荧光滴定实验证实了此探针是一种比率型探针,555 nm处的荧光强度与溶液中的生物硫醇分子浓度在0 ~ 20 μmol/L范围内呈良好的线性关系,对Cys、Hcy和GSH的检出限(3σ)分别为25.9、92.0和77.9 nmol/L.而吸收光谱、荧光光谱和质谱表征数据显示,生物硫醇与2,4-二硝基苯磺酸酯发生亲核取代反应并导致磺酸酯的分解.随着识别基团的解离,探针分子的d-PeT (donor-excited photoinduced electron transfer) 效应被解除,并出现非常明显的比色与荧光变化.HeLa细胞成像实验表明,探针DNSBN具有良好的生物相容性,能够对细胞外源性生物硫醇分子进行检测.     

L-structured quaternion matrices and quaternion linear matrix equations

This paper focuses on L-structured quaternion matrices. L-structured real matrices, conditions for the existence of solutions and the general solution of linear matrix equations were studied in the paper [Magnus JR. L-structured matrices and linear matrix equations, Linear Multilinear Algebra 1983;14:67–88]. In this paper, we present a theoretical study extending L-structured real matrices to L-structured quaternion matrices, and introduce some L-structured quaternion matrices. Based on them, we then discuss their applications in quaternion matrix equations.     

碱性溶液中酚酞褪色的动力学研究

酚酞是最常见的酸碱指示剂之一,在pH12.0时,酚酞会慢慢褪色,直至呈无色.利用酚酞在碱性溶液中慢慢褪色的过程,通过测定溶液吸光度的变化,测定酚酞在碱性溶液中反应的速率常数和反应级数,使学生进一步理解化学反应动力学的基本概念.     

Uncertainty Relation on Generalized Skew Information with aMonotone Pair

In this paper, we first define a generalized (f,g)-skew information \(\left |I_{ \rho }^{(f, g)}\right |(A)\) and two related quantity \(\left |J_{ \rho }^{(f, g)}\right |(A)\) and \(\left |U_{ \rho }^{(f, g)}\right |(A)\) for any non-Hermitian Hilbert-Schmidt operator A and a density operator ρ on a Hilbert space H and discuss some properties of them. And then, we obtain the following uncertainty relation in terms of \(\left |U_{ \rho }^{(f, g)}\right |(A)\):

$$\begin{array}{@{}rcl@{}} \left|U_{ \rho}^{(f, g)}\right|(A)\left|U_{ \rho}^{(f, g)}\right|(B)\geq \beta_{(f, g)}\left|Tr\left( f(\rho)g(\rho)[A, B]^{0}\right)\right|^{2}, \end{array} $$

which is a generalization of a known uncertainty relation in Ko and Yoo (J. Math. Anal. Appl. 383, 208–214, 11).