The mechanical properties of formamidinium halide perovskites FABX_3(FA=CH(NH_2)_2; B=Pb, Sn; X=Br, I)are systematically investigated using first-principles calculations. Our results reveal that FABX_3 perovskites pos...The mechanical properties of formamidinium halide perovskites FABX_3(FA=CH(NH_2)_2; B=Pb, Sn; X=Br, I)are systematically investigated using first-principles calculations. Our results reveal that FABX_3 perovskites possess excellent mechanical flexibility, ductility and strong anisotropy. We shows that the planar organic cation FA+ has an important effect on the mechanical properties of FABX3 perovskites. In addition, our results indicate that (i) the moduli(bulk modulus B, Young's modulus E, and shear modulus G) of FABBr_3 are larger than those of FABI_3 for the same B atom, and (ii) the moduli of FAPbX_3 are larger than those of FASnX_3 for the same halide atom. The reason for the two trends is demonstrated by carefully analyzing the bond strength between B and X atoms based on the projected crystal orbital Hamilton population method.展开更多
We and others have firmly established that surface IgM receptor (sIgM-R) crosslinking with antibodies to the i heavy chain (anti-i) leads to growth arrest and apoptosis in a series of well characterized B-cell lymphom...We and others have firmly established that surface IgM receptor (sIgM-R) crosslinking with antibodies to the i heavy chain (anti-i) leads to growth arrest and apoptosis in a series of well characterized B-cell lymphomas. This requires ablation of c-Myc protein expression and the concomitant induction of the cyclin-dependent-kinase inhibitor, p27Kip1. The signaling mechanisms regulating c-Myc and p27Kip1 protein expression are poorly understood. However, we recently established that sIgM-R mediated down-modulation of the PI-3K pathway directly affected c-Myc and p27Kip1 expression and accurately predicted growth展开更多
The reaction mechanisms of Ti（~3F） ＋ CH2C12→CH2=TiCl2 and Ti（~3F） ＋ CHC13→HC÷TiCl3 were investigated with Gaussian 03 program package at the B3PW91/6-311＋＋G（d,p）level.The computational results reveale...The reaction mechanisms of Ti（~3F） ＋ CH2C12→CH2=TiCl2 and Ti（~3F） ＋ CHC13→HC÷TiCl3 were investigated with Gaussian 03 program package at the B3PW91/6-311＋＋G（d,p）level.The computational results revealed that：1） Both reaction systems are initiated by Ti（~3F） atom attacking the C atom of CH2C12 and CHCl3 to activate a C-Cl bond;2） Both reaction systems were carried out via triplet reaction channels;3） CH2=TiCl2 has singlet and triplet isomers,and the singlet one is more stable;4） The HOMO of CH2=TiCl2（S） illustrates a π-bonding interaction between C and Ti;5） Only singlet HC÷TiCl3 was located,and the Mulliken atomic spin densities show that the two single electrons are mostly on the C atom.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 11572040the Thousand Young Talents Program of Chinathe Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund(second phase)under Grant No U1501501
文摘The mechanical properties of formamidinium halide perovskites FABX_3(FA=CH(NH_2)_2; B=Pb, Sn; X=Br, I)are systematically investigated using first-principles calculations. Our results reveal that FABX_3 perovskites possess excellent mechanical flexibility, ductility and strong anisotropy. We shows that the planar organic cation FA+ has an important effect on the mechanical properties of FABX3 perovskites. In addition, our results indicate that (i) the moduli(bulk modulus B, Young's modulus E, and shear modulus G) of FABBr_3 are larger than those of FABI_3 for the same B atom, and (ii) the moduli of FAPbX_3 are larger than those of FASnX_3 for the same halide atom. The reason for the two trends is demonstrated by carefully analyzing the bond strength between B and X atoms based on the projected crystal orbital Hamilton population method.
文摘We and others have firmly established that surface IgM receptor (sIgM-R) crosslinking with antibodies to the i heavy chain (anti-i) leads to growth arrest and apoptosis in a series of well characterized B-cell lymphomas. This requires ablation of c-Myc protein expression and the concomitant induction of the cyclin-dependent-kinase inhibitor, p27Kip1. The signaling mechanisms regulating c-Myc and p27Kip1 protein expression are poorly understood. However, we recently established that sIgM-R mediated down-modulation of the PI-3K pathway directly affected c-Myc and p27Kip1 expression and accurately predicted growth
基金financially supported by the National Natural Science Foundation of China(11174215)Natural Science Foundation of Shandong Province(ZR2012BL10)the University Science and Technology Project of Shandong Province(No.J13LD05)
文摘The reaction mechanisms of Ti（~3F） ＋ CH2C12→CH2=TiCl2 and Ti（~3F） ＋ CHC13→HC÷TiCl3 were investigated with Gaussian 03 program package at the B3PW91/6-311＋＋G（d,p）level.The computational results revealed that：1） Both reaction systems are initiated by Ti（~3F） atom attacking the C atom of CH2C12 and CHCl3 to activate a C-Cl bond;2） Both reaction systems were carried out via triplet reaction channels;3） CH2=TiCl2 has singlet and triplet isomers,and the singlet one is more stable;4） The HOMO of CH2=TiCl2（S） illustrates a π-bonding interaction between C and Ti;5） Only singlet HC÷TiCl3 was located,and the Mulliken atomic spin densities show that the two single electrons are mostly on the C atom.
