We report the structural,mechanical and electromagnetic properties of the intermetallic compound Mn_(23)C_(6).The bulk Mn_(23)C_(6)sample was synthesized using high temperature high pressure quenching method(HTHPQM),a...We report the structural,mechanical and electromagnetic properties of the intermetallic compound Mn_(23)C_(6).The bulk Mn_(23)C_(6)sample was synthesized using high temperature high pressure quenching method(HTHPQM),and investigated in detail by x-ray diffraction,electron microscope,magnetization and electrical resistivity measurements,etc.First-principles calculation based on density functional theory ab intio simulation was carried out to calculate the bonding and electromagnetic properties of Mn_(23)C_(6).Based on our experimental and simulated results,the Mn_(23)C_(6)in this work is single phase of a faced-centered cubic structure with space group Fm-3m(No.225).Determined by SEM and TEM,the bulk sample consists of monocrystal Mn_(23)C_(6)crystals with 2-15μm grain sizes,it is the quick quenching method in the synthesizing process that brings such small crystal grain size.Archimedes method gives its density of 7.14 g/cm^(3),95.74%of its theoretically calculated density 7.458 g/cm^(3).Owing to the abundant Mn 3d electrons and a framework of strongly linked Mn atoms in Mn_(23)C_(6),the electrical conductivity is up to 8.47×10^(-4)Ω·m,which shows that Mn_(23)C_(6)is a good conductor.Our magnetic susceptibility analyses reveal a magnetization peak in the M-T curve at 104 K,combined with the M-H curve and Curie-Weiss law,this peak usually means the transformation between paramagnetic and antiferromagnetic orders.To gain an insight into the mechanism of the magnetic phase transition,we calculated the magnetic properties,and the results show that different from normal antiferromagnetic order,the magnetic orders in Mn_(23)C_(6)consist of three parts,the direct ferromagnetic and antiferromagnetic exchange coupling interactions between Mn atoms,and the indirect antiferromagnetic super-exchange interaction between Mn and C atoms.Therefore,we reveal that the Mn_(23)C_(6)is a complex magnetic competition system including different magnetic orders and interactions,instead of the normal long-range antiferromagnetic order.展开更多
Cervical lesions have been regarded as the common and frequently occurring diseases in China.Recently,the morbidity and youth tendency of cervical cancer have gradually increased.Cervical cancer,related with human pap...Cervical lesions have been regarded as the common and frequently occurring diseases in China.Recently,the morbidity and youth tendency of cervical cancer have gradually increased.Cervical cancer,related with human papilloma virus(HPV)infection,has been one of the severest diseases threatening health and life of women,and is an infectious disease.The universality of HPV infection in the reproductive tract should not be ignored.The well-known risk factors of HPV infection in cervical lesions consist of high-risk sexual behaviors,immunosuppression,age,contraceptive methods,the concurrent infection of other sexually transmitted diseases,etc.The variation of cervical lesions induced by HPV infection is involved in the continuous pathological process,including the subclinical,latent,and persistent infection of high risk(HR)-HPV,chronic cervicitis with abnormal results of cytological examination,cervical intraepithelial neoplasia(CIN),and cervical cancer.The outcome of patients with HPV infection is influenced by many factors,such as HPV subtype dominance,persistent HPV infection,HPV loading dose,and multiple HPV infection.Controlling HR-HPV persistent infection should be an important strategy for reducing cervical lesions.展开更多
文摘We report the structural,mechanical and electromagnetic properties of the intermetallic compound Mn_(23)C_(6).The bulk Mn_(23)C_(6)sample was synthesized using high temperature high pressure quenching method(HTHPQM),and investigated in detail by x-ray diffraction,electron microscope,magnetization and electrical resistivity measurements,etc.First-principles calculation based on density functional theory ab intio simulation was carried out to calculate the bonding and electromagnetic properties of Mn_(23)C_(6).Based on our experimental and simulated results,the Mn_(23)C_(6)in this work is single phase of a faced-centered cubic structure with space group Fm-3m(No.225).Determined by SEM and TEM,the bulk sample consists of monocrystal Mn_(23)C_(6)crystals with 2-15μm grain sizes,it is the quick quenching method in the synthesizing process that brings such small crystal grain size.Archimedes method gives its density of 7.14 g/cm^(3),95.74%of its theoretically calculated density 7.458 g/cm^(3).Owing to the abundant Mn 3d electrons and a framework of strongly linked Mn atoms in Mn_(23)C_(6),the electrical conductivity is up to 8.47×10^(-4)Ω·m,which shows that Mn_(23)C_(6)is a good conductor.Our magnetic susceptibility analyses reveal a magnetization peak in the M-T curve at 104 K,combined with the M-H curve and Curie-Weiss law,this peak usually means the transformation between paramagnetic and antiferromagnetic orders.To gain an insight into the mechanism of the magnetic phase transition,we calculated the magnetic properties,and the results show that different from normal antiferromagnetic order,the magnetic orders in Mn_(23)C_(6)consist of three parts,the direct ferromagnetic and antiferromagnetic exchange coupling interactions between Mn atoms,and the indirect antiferromagnetic super-exchange interaction between Mn and C atoms.Therefore,we reveal that the Mn_(23)C_(6)is a complex magnetic competition system including different magnetic orders and interactions,instead of the normal long-range antiferromagnetic order.
基金supported by the Special Funds for State Key Development Program for Basic Research of China(973 Program)(No.2009CB521800)the National Natural Science Foundation of China(Grant Nos.30672227,30770913,30628029,30500596 and 30600667).
文摘Cervical lesions have been regarded as the common and frequently occurring diseases in China.Recently,the morbidity and youth tendency of cervical cancer have gradually increased.Cervical cancer,related with human papilloma virus(HPV)infection,has been one of the severest diseases threatening health and life of women,and is an infectious disease.The universality of HPV infection in the reproductive tract should not be ignored.The well-known risk factors of HPV infection in cervical lesions consist of high-risk sexual behaviors,immunosuppression,age,contraceptive methods,the concurrent infection of other sexually transmitted diseases,etc.The variation of cervical lesions induced by HPV infection is involved in the continuous pathological process,including the subclinical,latent,and persistent infection of high risk(HR)-HPV,chronic cervicitis with abnormal results of cytological examination,cervical intraepithelial neoplasia(CIN),and cervical cancer.The outcome of patients with HPV infection is influenced by many factors,such as HPV subtype dominance,persistent HPV infection,HPV loading dose,and multiple HPV infection.Controlling HR-HPV persistent infection should be an important strategy for reducing cervical lesions.
