We studied the local structure and properties of six-fold coordinated silicon(Si[6]) in BaOSiO2-P2O5 glasses. Nuclear magnetic resonance(NMR) and Raman spectroscopy revealed the existence of sixfold coordinated silico...We studied the local structure and properties of six-fold coordinated silicon(Si[6]) in BaOSiO2-P2O5 glasses. Nuclear magnetic resonance(NMR) and Raman spectroscopy revealed the existence of sixfold coordinated silicon species and network former units(NFUs) in the BaO-SiO2-P2O5 glasses. The glass transition temperature(Tg), which was measured by differential scanning calorimetry, increased rapidly along with the increase of SiO2 from 0 to 10 mol%, then declined and finally increased again, which showed a "Z" trend along with the increase of SiO2 while the density of the glasses showed the opposite trend. When the addition of SiO2 is 16 mol%, Tg decreased to an extremely low value(807.9 K). Besides, the Vickers indentation hardness(Hv) had been significantly enhanced from 4.66 to 6.63 GPa by adding 16 mol% SiO2. Furthermore, the liquid fragility index(m) of the glasses declined slowly firstly and then increased rapidly when the amount of SiO2 is greater than 13 mol%.展开更多
稀土元素是一种重要的不可再生资源,目前全球对稀土的需求依然在迅速增加。日本学者Kato等(2011)通过对太平洋沉积物大规模的采样发现,太平洋洋底含有大量的富稀土沉积物分布,并可能成为多金属结核、富钴结壳及多金属硫化物以外的又一...稀土元素是一种重要的不可再生资源,目前全球对稀土的需求依然在迅速增加。日本学者Kato等(2011)通过对太平洋沉积物大规模的采样发现,太平洋洋底含有大量的富稀土沉积物分布,并可能成为多金属结核、富钴结壳及多金属硫化物以外的又一大潜在的矿产资源。当前普遍认为深海沉积物中稀土元素的主要载体为生物磷酸盐(Yasukawa et al.,2014;Zhang et al.,2017),沉积物中的钙质和磷质组分均与稀土元素关系密切(邱忠荣等,2019)。本文对洋底沉积物中CaO/P2O5与REY关系进行系统性分析,为深海沉积物中CaO/P2O5可能作为指示REY含量的潜在指标提供一定的科学依据。展开更多
A practical system of metals-(2,4-pentanedionate) (M(acac)n (M= Fe, Zn, Co and V)) and P2O5 in the pres- ence of HNO3 catalyzes regioselective nitration of ar-himachalene 1 to mono-nitro-ar-himachalene 2 in mod- erate...A practical system of metals-(2,4-pentanedionate) (M(acac)n (M= Fe, Zn, Co and V)) and P2O5 in the pres- ence of HNO3 catalyzes regioselective nitration of ar-himachalene 1 to mono-nitro-ar-himachalene 2 in mod- erate to high yields. Under mild conditions, the selectivity of nitration of 1 to 2 is excellent compared to the classical method using the nitro-sulphuric mixture HNO3/H2SO4, both mono- and di-nitro-ar-himachalene 2 and 3 are obtained. The reaction offers a very good method for the preparation of nitro-aromatic compounds and provides a useful entry to new functionalized terpenic products.展开更多
基金Funded by National Natural Science Foundation of China(Nos.51772223,51372180)
文摘We studied the local structure and properties of six-fold coordinated silicon(Si[6]) in BaOSiO2-P2O5 glasses. Nuclear magnetic resonance(NMR) and Raman spectroscopy revealed the existence of sixfold coordinated silicon species and network former units(NFUs) in the BaO-SiO2-P2O5 glasses. The glass transition temperature(Tg), which was measured by differential scanning calorimetry, increased rapidly along with the increase of SiO2 from 0 to 10 mol%, then declined and finally increased again, which showed a "Z" trend along with the increase of SiO2 while the density of the glasses showed the opposite trend. When the addition of SiO2 is 16 mol%, Tg decreased to an extremely low value(807.9 K). Besides, the Vickers indentation hardness(Hv) had been significantly enhanced from 4.66 to 6.63 GPa by adding 16 mol% SiO2. Furthermore, the liquid fragility index(m) of the glasses declined slowly firstly and then increased rapidly when the amount of SiO2 is greater than 13 mol%.
文摘稀土元素是一种重要的不可再生资源,目前全球对稀土的需求依然在迅速增加。日本学者Kato等(2011)通过对太平洋沉积物大规模的采样发现,太平洋洋底含有大量的富稀土沉积物分布,并可能成为多金属结核、富钴结壳及多金属硫化物以外的又一大潜在的矿产资源。当前普遍认为深海沉积物中稀土元素的主要载体为生物磷酸盐(Yasukawa et al.,2014;Zhang et al.,2017),沉积物中的钙质和磷质组分均与稀土元素关系密切(邱忠荣等,2019)。本文对洋底沉积物中CaO/P2O5与REY关系进行系统性分析,为深海沉积物中CaO/P2O5可能作为指示REY含量的潜在指标提供一定的科学依据。
文摘A practical system of metals-(2,4-pentanedionate) (M(acac)n (M= Fe, Zn, Co and V)) and P2O5 in the pres- ence of HNO3 catalyzes regioselective nitration of ar-himachalene 1 to mono-nitro-ar-himachalene 2 in mod- erate to high yields. Under mild conditions, the selectivity of nitration of 1 to 2 is excellent compared to the classical method using the nitro-sulphuric mixture HNO3/H2SO4, both mono- and di-nitro-ar-himachalene 2 and 3 are obtained. The reaction offers a very good method for the preparation of nitro-aromatic compounds and provides a useful entry to new functionalized terpenic products.
