化学模拟生物固氮——Ⅸ 铁钼辅基模型化合物的合成和性能表征

本文曾在全国化学摸拟生物固氮协作组领导小组扩大会议(昆明,1980,8)上宣读。[中文文摘]采用乙二醇基阴离子作为活插头(可通过水解除去的双配位螯形配位体),对前文提出的合成方法作了重要改进,以期所合成的铁钼辅基模型化合物中Mo~(Ⅳ(Ⅲ))第一配位界内两个不稳定的配位体处于相邻的位置,如厦门模型Ⅲ(或厦门模型Ⅱ)所要求。合成和重组活性评价结果,重组活性比使用乙腈等为活插头的提高2个数量级,化学催化活性和选择性接近于天然FeMo-co水平。[英文文摘]A significant improvement has been made to the method previously proposed[3] for synthesizing FeMo-co modeling compounds. With the use of ethylene glycolate anion as labilizable blocking agent (hydrolyzable bidentatc chelating ligand)to protect two neighboring coordination sites in the first coordination sphere of MoIV(III) of the synthesized FeMo-co modeling compound, an increase in reconstituted-nitrogenase activity of 2 orders of magnitude of the sample synthesized (as compared with the use of acetoni-trile or other monodentare ligands as bloeking agents)has been obtained.Catalytic activity and selectivity assays as well as preliminary characterization by EPR method have also been made

HiPIMS室温溅射晶态氧化铝薄膜的粒子能量调控

晶态氧化铝薄膜与非晶态相比，具有更加优良的力学性能和宽波段光学透过性能。基于等离子体发射光谱（OES）反馈控制方法（PEM），引入高能脉冲磁控溅射（HiPIMS）技术，实现了室温条件下晶态γ-Al_(2)O_(3)薄膜的快速制备。采用高压探针、电流探针传感器和数字示波器监测HiPIMS的放电特性，采用等离子体发射监测器进行时间平均的OES研究，采用X射线衍射仪和扫描电镜分析了薄膜的晶相结构、晶粒尺寸及断面形貌，采用纳米压痕仪测试了薄膜的纳米硬度和模量。结果表明，HiPIMS条件下的成膜环境出现了大量的离子态，主要包括AlⅡ、ArⅡ甚至高价态粒子OⅣ参与反应。随着溅射电压由650 V增加至800 V，晶粒逐渐细化，由18 nm减小到8 nm，同时沉积速率从27 nm/min增加到55 nm/min。基体偏压对薄膜的沉积速率，微结构以及力学性能等方面均有显著的影响。随着基体偏压的增加，γ-Al_(2)O_(3)的择优取向由(422)转变为(311)，薄膜在偏压Us= -100 V条件下获得了最高硬度19.3 GPa。通过对成膜粒子能量的设计与调控，进一步优化了薄膜的结构和性能，为功能薄膜氧化铝的大规模产业化奠定了良好的应用基础

Effect of bias voltage on the growth of super-hard (AlCrTiVZr)N high-entropy alloy nitride films synthesized by high power impulse magnetron sputtering

The purpose of this paper is to explore the effect of bias voltage on plasma discharge characteristics, element concentration, microstructure, morphology, and mechanical properties of super-hard (AlCrTiVZr)N high-entropy alloy nitride (HEAN) films synthesized by high power impulse magnetron sputtering (HiPIMS). Results show that all HiPIMS-deposited (AlCrTiVZr)N films and the DCMS reference sample present a single NaCl-type FCC structure. Compared with DCMS, HiPIMS can produce a higher ionization fraction of the HEA target elements, thereby improving the structure and mechanical properties, while reducing the deposition rate. With increasing bias voltage in HiPIMS, the ion bombardment is continuously enhanced due to the increasing flux and energy of ionized particles reaching the films. The altered plasma environment splits the growth of (AlCrTiVZr)N films into two regions: The bias voltages of 0 V to -150 V offer a moderate ion bombardment effect, while further increasing bias voltage up to -200 V makes the ion bombardment effect excessive. It is observed that the (AlCrTiVZr)N films deposited at -150 V have a compact and featureless structure with preferred orientation of (111), the smallest grain size of 11.3 nm, a high residual compressive stress of -1.67GPa, thereby exhibiting the highest hardness of 48.3 GPa which attains the super-hard grade

白鲢三倍体及其核型的研究

白鲢卵授精后3分钟冷休克处理40分钟,其出苗率为0.28％,二龄鱼检查三倍体出现频率占被检查鱼的8.5％,镶嵌体占8.5％。 白鲢染色体2n=48,3n=72。 白鲢的核型2n有10对中着丝点染色体,12对近中着丝点染色体,2对近端着丝点染色体。3n有10套中着丝点染色体,12套近中着丝点染色体,2套近端着丝点染色体。 在自然界存在某些天然三倍体种群,并以雌核发育的方式来繁殖后代,如银鲫Carassius auratus gibelio Bloch(Cherfas 1966)。 自从Fankhauser