抗生素S—921菌株的特性研究

通过对抗苹果树皮腐烂病抗生素S—921菌株特性的研究,发现其特性基本属于不吸水链霉菌类群但与不吸水链霉菌又不完全相同,因此,我们认为它是一个新的变种。     

3—硝基—4—苯乙酰氨基茴香醚的合成方法之改进

本文报导以对茴香胺为原料合成标题化合物(NIPAA)。由于该化合物水解前后溶液的摩尔消光系数相差可达96倍,由黄绿色转变为深红色,因而有可能作为某些酰胺酶活性测定用试剂。     

新型的过渡金属聚吡咯配合物的合成与催化作用性能的研究 Ⅲ——二氯η-二聚吡咯合铂配合物

1 引言近年来,报导了许多阴离子掺杂的聚吡咯,但是,阳离子掺杂的聚吡咯还不多见报导。我们发现并合成出了二价铂离子和二聚吡咯形成的新型的二氯η—二聚吡咯合铂配合物,该配合物是黑色固体粉末,不溶于水和有机溶剂电对空气、酸和碱稳定,不导电,对H_2O_2有可观的催化活性,在文献中未见报导。 2 实验 2.1 药品和仪器铂氯酸钾,分析纯,沈阳试剂三厂吡咯,重新蒸馏提纯,收集131±1℃馏分     

Mn1.3Fe0.7PxSi1-x化合物的磁热效应

用球磨和烧结法制备了Mn1.3Fe0.7PxSi1-x系列化合物.磁性测量结果表明,随着P含量的增加,居里温度由x=0.45时的320K降到x=0.55时的209K;外加磁场变化为1.5T时,在居里温度209K附近,Mn1.3Fe0.7P0.55Si0.45的最大磁熵变为11.3 J/(kg·K).该化合物的热滞为10.4K.良好的磁热效应性能和低廉的原料价格使得该系列化合物有望成为室温区磁制冷工质.     

模块组合型多电平变换器的控制策略

对模块组合型多电平变换器(MMC)的脉冲调制策略和电压控制策略进行了理论分析和实验研究,建立了MMC系统的数学模型,在此基础上提出一种适用于MMC特点的载波移相SPWM控制策略和电压控制策略,无需额外的硬件电路,即可实现对MMC功率单元直流电容电压良好的稳压和均衡控制效果.通过一台三电平MMC实验样机的实验结果,分析了其稳态和静态工作特性,验证了控制策略的有效性.     

Hidden magnetism and quantum criticality in the heavy fermion superconductor CeRhIn5

With only a few exceptions that are well understood, conventional superconductivity does not coexist with long-range magnetic order (for example, ref. 1). Unconventional superconductivity, on the other hand, develops near a phase boundary separating magnetically ordered and magnetically disordered phases. A maximum in the superconducting transition temperature T(c) develops where this boundary extrapolates to zero Kelvin, suggesting that fluctuations associated with this magnetic quantum-critical point are essential for unconventional superconductivity. Invariably, though, unconventional superconductivity masks the magnetic phase boundary when T < T(c), preventing proof of a magnetic quantum-critical point. Here we report specific-heat measurements of the pressure-tuned unconventional superconductor CeRhIn5 in which we find a line of quantum-phase transitions induced inside the superconducting state by an applied magnetic field. This quantum-critical line separates a phase of coexisting antiferromagnetism and superconductivity from a purely unconventional superconducting phase, and terminates at a quantum tetracritical point where the magnetic field completely suppresses superconductivity. The T --> 0 K magnetic field-pressure phase diagram of CeRhIn5 is well described with a theoretical model developed to explain field-induced magnetism in the high-T(c) copper oxides, but in which a clear delineation of quantum-phase boundaries has not been possible. These experiments establish a common relationship among hidden magnetism, quantum criticality and unconventional superconductivity in copper oxides and heavy-electron systems such as CeRhIn5.     

Defective acidification of intracellular organelles in cystic fibrosis.

The phenotype of cystic fibrosis (CF) includes abnormalities in transepithelial transport of Cl- (refs 1-5), decreased sialylation and increased sulphation and fucosylation of glycoproteins, and lung colonization with Pseudomonas. It is not apparent how these abnormalities are interrelated, nor how they result from loss of function of the CF gene-encoded transmembrane regulator (CFTR). We have previously shown that that the pH of a secretory granule is regulated by the vesicular conductance for Cl- (ref. 11). Here we find defective acidification in CF cells of the trans-Golgi/trans-Golgi network, of prelysosomes and of endosomes as a result of diminished Cl- conductance. Sialytation of proteins and lipids is reduced and ligand traffic altered. These abnormalities can result from defective acidification because vacuolar pH regulates glycoprotein processing and ligand transport. The CF phenotype is similar to that of alkalinized cells and acidification-defective mutatants.