同步电机步进运动性能分析

针对常用的步进电机在结构上保留组合电磁铁的特征,导致电动机的容量小,输出功率小,效率低,不能满足人们对大功率步进电动机的需求。为此提出将步进电动机的设计思想从组合电磁铁提高为旋转磁场,并通过对同步电动机采用步进控制,模拟仿真该动态下电机各种参数对性能的影响,同时提出如何选取初值和确定合适的参数。     

光学成像无源定位及误差分析

分析了一种基于光学成像的目标无源定位方法,成像相机获取目标的图像与计算机相联,进行数字图像处理并计算出目标的方位角与俯仰角,达到对目标定位的目的。利用此方法可进行太阳的精确定位,并对此方法的误差进行了分析。     

高温超导衬底材料SrLaAlO4晶体的生长及特性

用提拉法生长了不开裂的高温超导衬底材料SrLaAlO4晶体,晶体尺寸为(25～30)mm×(50～60)mm.该晶体具有K2NiF4型结构,晶格常数为a=0.375nm,c=1.263nm.生长的晶体颜色随着生长时炉膛内氧气氛的含量的增加而逐渐加深.测量了晶体的室温下的介电常数及介电损耗分别为20及8×10-4.     

雨课堂背景下巧用案例法提高现代分析测试技术教学效果*

现代分析测试技术是工程类相关专业硕士研究生的必选课程,该课程传统的教学模式往往以教师讲授为主,学生实际操作的机会少,造成了学生学习积极性不高。和传统的教学模式相比,雨课堂增加了教师和学生间的沟通互动和课堂趣味性,有利于提高学生的课堂积极性。基于雨课堂,将教师的科研作为案例融入课堂教学,同时采用“打卡通关”式的案例教学模式,通过案例模拟实际测试,提供真实情境教学,激发学生学习兴趣,提高学生的课堂参与度,明显提高了该课程的学习效果。     

A DFT Investigation on the Electronic Structures and Au Adatom Assisted Hydrogenation of Graphene Nanoflake Array

Graphene nanoribbons with zigzag edges(ZGNRs) have attracted much attention for their spin-polarized edge states predicted more than 15 years ago. Since the ZGNRs are fabricated on metal substrates using molecular precursors, due to their strong coupling with metal substrates, experimental detection of the spin-polarized edge states is still difficult. Here, we design a partially hydrogenated graphene(PHGr), in which periodic hexagonal graphene nanoflakes(GNFs) with zigzag boundaries are embedded in a hydrogenated graphene layer. Using density functional theory(DFT) based first-principles calculations, we find that the hexagonal GNFs exhibit spin-polarized boundary states at their opposite zigzag boundaries, which is similar with the bow-tie-shaped GNFs and ZGNRs. DFT calculations demonstrate that the PHGr is a semiconductor with an antiferromagnetic ground state. Moreover, the antiferromagnetic boundary states and semiconduc-ting properties keep unchanged when the size of GNF varies from 1.4 nm to 2.3 nm. The robustness of the spin-polarized boundary states enables this PHGr as a robust material for detecting spin-polarized boundary states coming from zigzag boundaries. In addition, we find that single Au atoms selectively adsorbed on boundaries catalyze H₂ dissociation and therefore lower the barrier of graphene hydrogenation. Therefore, the PHGr can be used not only in carbon-based spintronic devices but also as a platform for single atom catalyst.     

自卤仿产生二卤卡宾的单电子转移过程

研究了从卤仿和氢氧化钠生成二卤卡宾的反应,根据化学和物理研究证明,是一单电子转移(SET)的反应机理.在类卡宾、三卤碳阴离子和二卤卡宾间设有平衡存在,卤素交换是单电子转移过程中形成的三卤甲基和二卤甲基游离基所引起的,它优先于卡宾对C=C的加成而发生,反应的初始电子给予体是CX3主要电子接受体是过量存在的卤仿.     

STUDY ON INDUCTION OF DIFFERENTIATION OF A HUMAN MEGAKARYOBLASTIC LEUKEMIA CELL LINE (HIMeg) BY 1,25-DIHYDROXYVITAMIN D_3

It is reported that 1,25-dihydroxyvitamin D_3(1,25(OH)_2D_3), a physiological factor, has aninductive effect on the differentiation of a novel human megakaryoblastic leukemia cell line(HIMeg) in vitro. At the concentrations ranging from 10~(-9) to 10~(-6) mol/L, 1,25(OH)_2D_3 showedinhibition of proliferation on HIMeg cells which was demonstrated by count of survivalcells and cloning efficiency. Meanwhile, using light/electron microscopy, stain of cytochem-istry (including immunoenzymatic technique) and flow cytometry, we found that HIMeg cellscould be further induced into more mature cells in megakaryocytic lineage confirmed by aseries of evidence, including the changes of cell morphology/structure and cytochemistry,increased expression of differentiation antigens on the cell surface, and polyploidization.So, it is possible for 1,25(OH)_2D_3 to promote the differentiation of the cells in megakaryo-cytic lineage in vivo and to be used to treat acute megakaryoblastic leukemia and other di-seases with mal     

简易电沉积法制备CoFe-P催化剂用于高效析氧反应

开发低成本、高活性且稳定的非贵金属催化剂是实现大规模电解水制氢的关键所在。在此,我们通过简便、合理的电沉积法在泡沫镍(NF)上构建了一种具备超薄二维纳米片形貌的高度非晶相Co1Fe1-P薄膜用于高效催化析氧反应（OER）。在1.0mol·L^-1 KOH溶液中,所制备的Co1Fe1-P/NF催化剂在电流密度为10和100 mA·cm^-2处的过电位分别为274.4和329.5 mV,Tafel斜率仅为45.3 mV·dec^-1,可以媲美商业RuO₂催化剂。此外,Co1Fe1-P/NF催化剂在10 mA·cm^-2的100 h计时电压法测试和1 000次循环伏安法测试中均表现出卓越的催化稳定性。Co1Fe1-P/NF催化剂优秀的催化活性归因于其独特的形貌、高度非晶相结构提供的低能垒、优化的电子结构以及钴磷化物和铁磷化物的强协同效应。     

含硫正离子聚类肽水凝胶的合成与性能

通过伯胺引发肌氨酸-N-硫代羧酸酐(Sar-NTA)和N-烯丙基甘氨酸-N-硫代羧酸酐(NGA-NTA)的开环聚合制备了一种三嵌段聚类肽, 即聚(N-烯丙基甘氨酸)-b-聚肌氨酸-b-聚(N-烯丙基甘氨酸)(PNAG-b-PSar-b-PNAG, 简称PASA); 然后通过PASA侧链上的烯丙基与3,6-二氧杂-1,8-辛烷二硫醇之间的巯-烯“点击”化学反应合成了不同肌氨酸(Sar)摩尔分数的聚类肽水凝胶(HG). 巯-烯“点击”反应生成的大量硫醚基团可进一步与环氧化合物反应, 在水凝胶的网络骨架中生成硫正离子, 从而获得具有固有抗菌能力的含硫正离子聚类肽水凝胶(S⁺HG). S⁺HG具有优异的吸水能力, 能够在1 min内达到吸水平衡, 饱和溶胀率高达2024%. S⁺HG内部由大量规则的连续海绵孔状结构组成, 能够承受一定的剪切、 摩擦及挤压等外界应力. S⁺HG具有强效的广谱抗菌能力, 对革兰氏阴性的大肠杆菌(E. coli)和革兰氏阳性的金黄色葡萄球菌(S. aureus)的抗菌率都在99.99%以上.     

能源化学课程思政教学探索*

课程思政建设是落实立德树人根本任务的关键环节,是新时代教育改革背景下提出的创新教育理念。通过充分挖掘蕴含在能源化学专业知识中的思政资源,实现课程教学与思政教育的完美结合,培养学生的爱国奋斗精神、工匠精神、创新意识、人文精神及文化自信精神等,推动专业教学由知识导向型向能力和素质导向型转变。