67 research outputs found
CCCCC pentadentate chelates with planar Möbius aromaticity and unique properties
本课题充分发挥了厦门大学多学科协同研究优势,通讯作者为夏海平教授(合成、表征)、刘刚教授(生物医学应用)和吕鑫教授(理论计算)。合成实验和结构表征由朱从青(第一作者,目前在麻省理工学院、2005年诺贝尔化学奖得主Richard Schrock教授课题组从事博士后研究)完成;生物医学应用由杨彩霞(共同第一作者)、林凎、杨宇惠、王晓勇合作完成;理论计算由朱军、王永恒、朱从青完成。美国NIH的陈小元教授参与了生物医学应用的讨论。该研究工作得到国家自然科学基金委、科技部项目的支持。The coordinating atoms in polydentate chelates are primarily heteroatoms. We present the first examples of pentadentate chelates with all binding atoms of the chelating agent being carbon atoms, denoted as CCCCC chelates. Having up to five metal-carbon bonds in the equatorial plane has not been previously observed in transition metal chemistry. Density functional theory calculations showed that the planar metallacycle has extended Craig-Möbius aromaticity arising from 12-center–12-electron dπ-pπ π-conjugation. These planar chelates have broad absorption in the ultraviolet-visible–near-infrared region and, thus, notable photothermal performance upon irradiation by an 808-nm laser, indicating that these chelates have potential applications in photothermal therapy. The combination of facile synthesis, high stability, and broad absorption of these complexes could make the polydentate carbon chain a novel building block in coordination chemistry.the National Basic Research Program of China (nos. 2012CB821600 and 2014CB744503) , the National Science Foundation of China (nos. 21332002, 81422023, 51273165, 21490573, and 21573179)
长臀属鱼类多变量形态分析及物种有效性研究
采用形态度量学方法对分布于我国珠江水系、元江水系及海南岛诸水系的长臀属3种鱼类,共66尾个体的 43个测量性状进行了主成分分析。研究结果表明长臀属鱼类不能在形态上进行区别。作者认为长臀属鱼类 只存在一个有效种
Parallel type light-duty robot joint variable-stiffness actuator
本发明属于机器人关节技术领域,特别涉及一种并联式轻型机器人关节变刚度执行器。包括动力输入部、动力输出部、刚度调节部及刚度变化执行部,其中动力输入部和动力输出部转动连接,刚度调节部设置于动力输入部上、且通过刚度变化执行部与动力输出部连接;当动力输出部受到不同载荷,动力输出部相对于动力输入部产生相对转动,使刚度变化执行部产生不同的工作状态,实现刚度的非线性变化;当动力输出部受到载荷一定时,通过刚度调节部调节刚度变化执行部的工作状态,使动力输入部和动力输出部的转动角度发生变化,实现刚度的主动调节。本发明体积更小,质量更轻,同时缩短了刚度调节时间
Single-driven self-adaptive mechanical finger
本发明涉及机器人关节技术领域,具体地说是一种单驱动形状自适应机械手指,包括手掌连接部、指节传动组件、指节动力汲取组件和多个指节,所述多个指节依次通过铰接轴铰接,且第一指节通过铰接轴与手掌连接部铰接,在手掌连接部上设有驱动第一指节摆动的驱动轴,各个铰接轴之间均通过指节传动组件相连,各个铰接轴上均设有指节动力汲取组件,所述指节动力汲取组件包括第一摩擦盘、第二摩擦盘和弹簧,第一摩擦盘和第二摩擦盘紧贴,且第一摩擦盘空套于对应的铰接轴上并与相邻的指节传动组件相连,第二摩擦盘设有一个随铰接轴转动的盘套,弹簧套装在所述盘套上。本发明采用一个驱动源驱动整个手指,且每个指节的输出扭矩可控,形状自适应能力强
一种电池级纳米草酸亚铁的制备方法
本发明涉及一种电池级纳米草酸亚铁及其制备方法以及应用,其中草酸亚铁的粒径在三维空间中至少有一维处于纳米尺度范围(500纳米以下)或由它们作为基本单元构成的材料;制备方法包括下述两个特征步骤:一、硫酸亚铁纯化,通过加入铁粉、凝絮剂和杂质金属离子沉淀剂有效地降低了硫酸亚铁溶液的杂质金属离子的含量,提高了反应产物草酸亚铁溶液的纯度;二、利用在反应过程中引入增稠剂、沉淀剂获得了纳米级草酸亚铁。本发明方法具有原料充足、工艺流程简单、产品质量好且稳定、成本低等特点,利用本发明的电池级纳米草酸亚铁制备的磷酸铁锂正极材料性能优异,为磷酸铁锂的大规模制备提供了优质的铁源,同时也为硫酸亚铁废弃物的回收利用提供了一条新的途径
一种电池级草酸亚铁的制备方法
本发明提供了一种电池级草酸亚铁的方法,其特征在于向制备草酸亚铁的前躯体中加入高分子量的水溶性高分子,与前躯体形成络合物结构或其它结构,进而通过与沉淀剂反应制备电池级草酸亚铁。其中前躯体硫酸亚铁的制备方法为将钛白粉的副产物硫酸亚铁经溶解、加入还原铁粉、过滤所得。本发明利用在反应过程中引入高分子量的水溶性高分子有效地抑制了草酸亚铁的粒径,获得了粒径均匀的超细草酸亚铁。另外,本发明具有原料充足、工艺流程简单、产品质量好且稳定、成本低等特点,同时为硫酸亚铁废弃物的回收利用提供了一条新的途径
Design and analysis of spring parallel variable stiffness actuator based on antagonistic principle
Human-machine collaboration is an inevitable development trend of robots, and the variable stiffness joints of robots has been increasingly investigated by researchers. The variable stiffness joint based on the antagonism principle has received extensive attention, where its variable stiffness actuator mainly including nonlinear elastic components and antagonistic force pairs are the research hotspots. In this paper, a spring parallel variable stiffness actuator (SPVSA) based on a novel variable stiffness principle is proposed, in which the linear spring is arranged in parallel with the antagonistic force, so that the elastic components are no longer involved in the antagonism. The variable stiffness actuator effectively eliminates the antagonistic effect of the elastic components and improves the shock absorption and energy storage capacity. And based on the passive and active stiffness adjustment modes, the variable stiffness speed can be effectively improved. Meanwhile, the use of extremely ultralight springs and wire ropes simplifies the structure of the actuator and reduces the quality and size of the joints. In this paper the model design, related theoretical analysis and simulation analysis of SPVSA are carried out. And the effectiveness and advancement of SPVSA are verified by experiments
(n)nc-Si:H/(p)c-Si异质结中载流子输运性质的研究
采用常规等离子体增强化学气相沉积工艺,以高H_2稀释的SiH_4作为反应气体源和PH_3作为磷原子的参杂剂,在p型(100)单晶硅C(p)c-Si)衬底上,成功地生长了施主掺杂型纳米硅膜C(n)nc-Si:H),进而制备了(n)nc-Si;H/(p)c-Si异质结,并在230-420K温度范围内实验研究了该异质结的I-V特性。结果表明,(n)nc-Si:H/(p)c-Si异质结为一典型的突变异质结构,具有良好的温度稳定性和整流特性。正向偏压下,该异质结的电流输运机理为复合-隧穿模型。当正向偏压V_F1.0V时由隧穿机理决定。反向偏压下,该异质结具有良好的反向击穿持性
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