k路覆盖图的新充分条件

设G是一个n阶简单连通图。如果其顶点集V(G)能被k条或更少的点不交的路覆盖,则图G是k-路覆盖的。分别用距离谱半径、距离无符号拉普拉斯谱半径、Wiener指数和Harary指数得到了图G是k-路覆盖的新的充分条件。     

Impurity characteristics of group V and VII element-doped two-dimensional ZrSe2 monolayer

Through first-principles calculations, we investigate the electronic structures, formation energy and transition level of the selected group V and VII impurities in the two-dimensional ZrSe₂ monolayer. Our results indicate that group V and VII atoms substituting Se atom can be easier under Zr-rich experiment conditions. Moreover, group V element substituting doping can induce p-type carrier due to their negative formation energy and shallow transition level, while group VII doping can not be effective to induce the n-type impurities. In particular, N substituting Se exhibits the lowest formation energy and shallowest transition level, which indicates that N impurities can offer effective p-type carriers in the ZrSe₂ monolayer.     

高温超导薄膜衬底材料-SrTiO_3双晶的研究

SrTiO3双晶基片是高温超导电子学研究中外延YBCO薄膜所需要的基础材料;是制作高温超导量子干涉器件(SQUID)的核心。由于其特殊的制造工艺,加之研究因素所附加的高昂成本,至今只有少数国家涉足这一领域。文中展示作者在钛酸锶双晶研究方面所取得的阶段性进展。     

Near-zero thermal expansion of In_(2(1-x))(HfMg)_xMo_3O_(12) with tailored phase transition

Solid solutions of In_(2(1-x)(HfMg)_xMo_3O_(12) are synthesized by solid state reaction with the aim to reduce the phase transition temperature of In_2Mo_3O_(12) and improve its thermal expansion property.The effects of(HfMg)~(6+) incorporation on the phase transition and thermal expansion are investigated.It is shown that the monoclinic-to-orthorhombic phase transition temperature obviously decreases and the coefficient of thermal expansion(CTE) of the orthorhombic becomes less negative and approaches to zero with increasing the content of(HfMg)~(6+).A near zero thermal expansion covering the case at room temperature(RT) is achieved for the solid solutions with x ≥ 0.85,implying potential applications of this material in many fields.     

新型四阳离子型1,2,3-三唑鎓环蕃的合成

以间苯二酚为原料,经5步反应制得中间体4,4′-［4,6-双(己氧基)-1,3亚苯基］双{1-［4-(叠氮甲基)苯基］-1H-1,2,3-三氮唑}(6); 6与1,5-二乙炔基-1,4-二(己氧基)苯在高度稀释的条件下经Click反应环合制得1,2,3-三唑环蕃(7); 7与三甲基氧鎓四氟硼酸盐反应合成了全甲基化的新型1,2,3-三唑鎓环蕃,其结构经¹H NMR, ¹³C NMR和HR-ESI-MS表征。     

金属杂质粒子诱导薄膜的损伤机理研究

薄膜内的杂质粒子极易诱导薄膜损伤,研究了金属粒子诱导HfO₂薄膜损伤的特征,并基于金属粒子的热力学过程进行了分析。金属粒子对激光的强烈吸收将引起薄膜的熔化、气化以及电离,从而引起薄膜的剥离和脱落,形成圆状坑点;金属粒子对激光的吸收、热扩散以及热膨胀效应与其尺寸等密切相关;从温升规律分析,在相同激光能量辐照下,粒子大小引起的温升不同,从而形成大小不一的点坑状破坏点,且存在一个温升效应最强的粒径,最易引起薄膜的损伤;从金属粒子激光等离子体的辐射效应分析,金属粒子的辐射谱主要集中在紫外部分,辐射光子能量比入射激光光子能量强,具有更强的电离能力,从而加剧了薄膜的去除。     

基于递归型神经网络动力学求解时变凸二次规划

为了在线求解时变凸二次规划问题,实现误差精度更高、求解时间更短和收敛速度更快的目标。本文采用了求解问题更快的时变网络设计参数,选择了有限时间可以收敛的Sign-bi-power激活函数,构造了一种改进的归零神经网络动力学模型。其后,分析了模型的稳定性和收敛性,得到其解能够在有限时间内收敛。最后,在仿真算例中,与传统的梯度神经网络和归零神经网络模型相比,所提模型具有更高的误差精度、更短的求解时间和更快的收敛速度,优于前两种网络模型。     

彩色多普勒超声在浅表软组织肿块诊断中的应用分析

本研究探讨彩色多普勒超声在浅表软组织肿块诊断中的应用价值。选取浅表组织肿块患者210例,其中良性病变患者172例,恶性病变患者38例,给予彩色多普勒超声检查。结果显示,恶性病变形态不规则、内部不均匀低回声、边界模糊、内部血流丰富比例明显高于良性病变(P<0.05);恶性病变病灶收缩期峰值流速(Vmax)和阻力指数(RI)明显高于良性病变(P<0.05),病灶最大长径/最大短径(L/S)明显低于良性病变(P<0.05);年龄、形态、内部回声、边界、内部血流、Vmax和RI建立Logistic回归方程,其诊断恶性病变的ROC曲线下面积为0.910(P<0.05),灵敏性和特异性达到84.00%和96.00%。可见彩色多普勒超声在浅表软组织肿块良恶性诊断中有较好的应用价值。     

CBL结合学科思维导图在生物化学检验教学中的应用

为了培养高职高专检验专业学生在临床思维、问题探究及知识系统性掌握运用等方面的综合能力,在生物化学检验教学中探索了CBL与学科思维导图相结合的教学方法,多年的教学实践证明,这是一种可以用于提高学习者综合能力的良好的教学方法。     

A note on two-agent scheduling on an unbounded parallel-batching machine with makespan and maximum lateness objectives

This paper studies the two-agent scheduling on an unbounded parallel-batching machine. In the problem, there are two agents A and B with each having their own job sets. The jobs of a common agent can be processed in a common batch. Moreover, each agent has an objective function to be minimized. The objective function of agent A is the makespan of his jobs and the objective function of agent B is maximum lateness of his jobs. Yazdani Sabouni and Jolai [M.T. Yazdani Sabouni, F. Jolai, Optimal methods for batch processing problem with makespan and maximum lateness objectives, Appl. Math. Model. 34 (2010) 314–324] presented a polynomial-time algorithm for the problem to minimize a positive combination of the two agents’ objective functions. Unfortunately, their algorithm is incorrect. We then dwell on the problem and present a polynomial-time algorithm for finding all Pareto optimal solutions of this two-agent parallel-batching scheduling problem.