The word “clusters” in scientific terminology as aggregated molecules or atoms appeared in chemistry relatively recently. The terms clusters have been used intensively since the discovery of fullerenes. The term clu...The word “clusters” in scientific terminology as aggregated molecules or atoms appeared in chemistry relatively recently. The terms clusters have been used intensively since the discovery of fullerenes. The term cluster is not a new one for other branches of science such as astrophysics-star cluster, globular cluster, galaxy cluster, in biology and medicine-cancer cluster, genetic cluster, or in computing-data cluster. Adducts in chemistry were known significantly earlier. Both clusters and adducts are assemblies of atoms or molecules that are held together by weak van der Waals or London dispersion forces. Clusters are homogeneous and usually consist of one sort of atom or molecule. Clusters can also be a host for other types of atoms or molecules. Adducts usually consist of two different types of molecules, one of which is the host molecule. Both clusters and adducts are well defined by IUPAC. The present short review describes some important phenomena of these intriguing associations, which have interest for chemical extraction, separation, analysis, and for nature in general.展开更多
Similar element substitution has been applied for improving glass forming ability （GFA） in AI86NigLa5 amor- phous alloy. The effects of La-Ce and Ni-Co pairs on the GFA, magnetic properties and hardness of Al-Ni-La ...Similar element substitution has been applied for improving glass forming ability （GFA） in AI86NigLa5 amor- phous alloy. The effects of La-Ce and Ni-Co pairs on the GFA, magnetic properties and hardness of Al-Ni-La alloy were investigated by using X-ray diffraction （XRD）, transmission electron microscopy （TEM）, differential scanning calorimetry （DSC）, magnetometer and hardness-tester. The results show the GFA of the samples in the order of Al86（Ni0.5Co0.5）9（La0.5Ce0.5）5〈 A186Ni9Las〈A186Ni9（La0.5Ce0.5）5, implying that similar element substitution has a limited enhancing effect on the GFA of the present Al-Ni-La alloy. In addition, the measured samples display a diamagnetic behavior at room temperature. The variations of diamagnetic behavior as well as the microhardness of the samples are strongly dependent on the microstructure, i.e., the amounts of the icosahedral structure and precipitates, after the similar element substitution in the Al-Ni-La alloy.展开更多
文摘The word “clusters” in scientific terminology as aggregated molecules or atoms appeared in chemistry relatively recently. The terms clusters have been used intensively since the discovery of fullerenes. The term cluster is not a new one for other branches of science such as astrophysics-star cluster, globular cluster, galaxy cluster, in biology and medicine-cancer cluster, genetic cluster, or in computing-data cluster. Adducts in chemistry were known significantly earlier. Both clusters and adducts are assemblies of atoms or molecules that are held together by weak van der Waals or London dispersion forces. Clusters are homogeneous and usually consist of one sort of atom or molecule. Clusters can also be a host for other types of atoms or molecules. Adducts usually consist of two different types of molecules, one of which is the host molecule. Both clusters and adducts are well defined by IUPAC. The present short review describes some important phenomena of these intriguing associations, which have interest for chemical extraction, separation, analysis, and for nature in general.
基金the National Natural Science Foundation of China (Nos. 50871061, 50871062, 50831003and 50631010)the Excellent Youth Science and Technology Award of Shandong Province (No. 2008BS04020)+1 种基金the project NCET-06-584the National Basic Research Program of China ("973 Program", No. 2007CB613901)for financial supports
文摘Similar element substitution has been applied for improving glass forming ability （GFA） in AI86NigLa5 amor- phous alloy. The effects of La-Ce and Ni-Co pairs on the GFA, magnetic properties and hardness of Al-Ni-La alloy were investigated by using X-ray diffraction （XRD）, transmission electron microscopy （TEM）, differential scanning calorimetry （DSC）, magnetometer and hardness-tester. The results show the GFA of the samples in the order of Al86（Ni0.5Co0.5）9（La0.5Ce0.5）5〈 A186Ni9Las〈A186Ni9（La0.5Ce0.5）5, implying that similar element substitution has a limited enhancing effect on the GFA of the present Al-Ni-La alloy. In addition, the measured samples display a diamagnetic behavior at room temperature. The variations of diamagnetic behavior as well as the microhardness of the samples are strongly dependent on the microstructure, i.e., the amounts of the icosahedral structure and precipitates, after the similar element substitution in the Al-Ni-La alloy.
