三项式xn-x-a的二次不可约因式

设n是正整数,f(x)=xn-x-a,其中a是非零整数. 证明了当n>5时,如果f(x)有首项系数为1的二次整系数不可约因式g(x),则必有n≡2(mod6),a=-1,g(x)=x2-x+1或者n=7,a=±280,g(x)=x2t(±)x+5.     

二羰基环戊二烯基（三环己基锡基）铁的晶体结构

关于（三烃基锡基）二数基环戊二烯基铁类配合物的合成反应已进行了许多研究D'，并发现某些这类配合物具有一定的催化聚合作用或抗肿瘤活性［'·'j．这类配合物中已见报道晶体结构的只有烃基为三苯基作配体时的配合物CP（CO）。FesnPh。D'，为了便于比较及研究结构和性能的关系，我们以三环已基为锡的配体，以与文献［'j中近似的方法合成了配合物CP（CO）。Fesfl（C6HI人，并进行了IR、NMR的测定．X光四圆衍射仪对所得单晶的结构测定结果表明，该配合物具有与CP（CO）。F。SnPh。相近的晶体结构．1标题配合物的制备与谱学表征1…     

动脉中非平稳流动壁面剪切力及其Hilbert-Huang变换

本文通过数值方法求解均匀动脉中的非平稳脉动流,给出了通过测量非平稳脉动血流量确定壁面切应力的方法.作为算例,采用实测的大鼠颈总动脉流量信号,求出了均匀动脉壁面切应力波形.进一步对求得的切应力波形进行经验模态分解(EMD),得到了切应力波形的各内在模态(IMF),以及Hilbert幅值谱.从切应力波形经Hilbert-Huang变换得到的IMF和Hilbert谱图可以明显地看出切应力各频率成分的物理意义.所得结果为进一步深入研究非平稳脉动切应力与血管重建的关系提供了一种方法学基础.     

Suzuki Reaction of Aryl Bromides Using a Phosphine-Free Magnetic Nanoparticle-Supported Palladium Catalyst

A palladium catalyst immobilized on superparaganetic nanoparticles was prepared with a palladium loading of 0.30 mmol/g. The catalyst was characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, thermogravimetric analysis, Fourier transform infrared, atomic absorption spectrophotometry, and nitrogen adsorption. The immobilized palladium catalyst was an efficient catalyst without added phosphine ligands for the Suzuki cross-coupling reaction of several aryl bromides with phenylboronic acid. The recovery of catalyst was simply by magnetic decantation in the presence of a magnet. The immobilized palladium catalyst can be reused many times without significant degradation in catalytic activity. No leaching of active palladium species into the reaction solution was detected.     

三元TBZ/HPB-铜(Ⅱ)-L-蛋氨酸配合物的合成、表征、抑菌活性及与DNA的作用

本文合成了2个新的三元铜(Ⅱ)配合物:[Cu(TBZ)(L-Met)(H2O)]ClO4.H2O(1)和[Cu(HPB)(L-Met)]ClO4(2)[TBZ=2-(4′-噻唑基)苯并咪唑,HPB=2-(2-吡啶)苯并咪唑,L-Met=L-蛋氨酸]。通过元素分析、摩尔电导率、IR、UV-Vis及电喷雾质谱对这些配合物进行了表征。用二倍稀释法研究了配合物的抗菌活性,发现配合物对金黄色葡萄球菌(Staphylococcus aureus,G+),枯草杆菌(Bacillussubtilis,G+),沙门氏杆菌(Salmonella,G-)和大肠杆菌(Escherichia coil,G-)具有良好的抑制作用。采用电子吸收光谱、荧光光谱、粘度测定及琼脂凝胶电泳方法研究了配合物与DNA的相互作用,结果表明,配合物以插入方式与DNA作用,在维生素C存在下通过羟自由基.OH,单线态氧1O2或者1O2类似物如Cu-O2,切割pBR322 DNA双螺旋结构。     

互补对偶结构的三值ECL锁存器设计

在分析发射极耦合逻辑(ECL)电路的互补对偶特性基础上,指出了差分对的两个开关变量的不独立性及互补对偶特性,并设计了互补对偶结构的ECL三值D型锁存器.这种新型的D型锁存器电路比传统电路具有更简单的电路结构.它的输出是互补的双轨三值输出系统.应用这种新型锁存器设计的D触发器及时序电路将具有更简单的电路结构.     

Gamma-ray spectroscopy of87Y

The level structure of⁸⁷Y has been studied using in-beam γ-ray spectroscopic methods. Many previously unknown states have been observed. Members of theπ(g _9/2 )ν(g _9/2)^?2 multiplet are identified. The results are discussed in terms of the weak-coupling model.     

The sorption of polymetaphosphate on anion exchange resins

From a solution of sodium polymetaphosphate, strongly basic anion exchange resins can retain a greater amount of polymetaphosphate than that corresponding to the exchange capacity. Sodium ions are held by the polymetaphosphate form of the resin and these sodium ions can be exchanged for other ions.