The H2Ge=Ge：, as well as and its derivatives （X2Ge=Ge：, X=H, Me, F, C1, Br, Ph, At, ...） is a kind of new species. Its cycloaddition reactions is a new area for the study of germylene chemistry. The mechanism of t...The H2Ge=Ge：, as well as and its derivatives （X2Ge=Ge：, X=H, Me, F, C1, Br, Ph, At, ...） is a kind of new species. Its cycloaddition reactions is a new area for the study of germylene chemistry. The mechanism of the cycloaddition reaction between singlet Me2Ge=Ge： and acetaldehyde was investigated with the B3LYP/6-31G＊ method in this work. From the potential energy profile, it could be predicted that the reaction has one dominant reaction pathway. The reaction rule is that the two reactants firstly form a four-membered Ge-heterocyclic ring germylene through the [2＋2] cycloaddition reaction. Because of the 4p unoccupied orbital of Ge： atom in the four-membered Ge-heterocyclic ring germylene and the ~ orbital of acetaldehyde forming a r^--~p donor-acceptor bond, the four-membered Ge-heterocyclic ring germylene further combines with acetaldehyde to form an intermedi- ate. Because the Ge atom in intermediate happens sp3 hybridization after transition state, then, intermediate isomerizes to a spiro-Ge-heterocyclic ring compound via a transition state. The research result indicates the laws of cycloaddition reaction between Me2Ge=Ge： and ac- etaldehyde, and lays the theory foundation of the cycloaddition reaction between H2Ge=Ge： and its derivatives （X2Ge=Ge：, X=H, Me, F, C1, Br, Ph, At, ...） and asymmetric ^-bonded compounds, which are significant for the synthesis of small-ring and spiro-Ge-heterocyclic ring compounds.展开更多
H2Ge=Si： and its derivatives （X2Ge=Si：, X=H, Me, F, C1, Br, Ph, Ar, ...） are new species. Its cycloaddition reactions are new area for the study of silylene chemistry. The cycloaddition reaction mechanism of singl...H2Ge=Si： and its derivatives （X2Ge=Si：, X=H, Me, F, C1, Br, Ph, Ar, ...） are new species. Its cycloaddition reactions are new area for the study of silylene chemistry. The cycloaddition reaction mechanism of singlet H2Ge=Si： and formaldehyde has been investigated with the MP2/aug-cc-pVDZ method. From the potential energy profile, it could be predicted that the reaction has one dominant reaction pathway. The reaction rule is that two reactants firstly form a four-membered Ge-heterocyclic ring silylene through the [2＋2] cycloaddition reaction. Because of the 3p unoccupied orbital of Si： atom in the four-membered Ge-heterocyclic ring silylene and the π orbital of formaldehyde forming a π--p donor-acceptor bond, the four-membered Ge-heterocyclic ring silylene further combines with formaldehyde to form an intermediate. Because the Si： atom in the intermediate undergoes sp3 hybridization after transition state, then the intermediate isomerizes to a spiro-Si-heterocyclic ring compound involving Ge via a transition state. The result indicates the laws of cycloaddition reaction between H2Ge=Si： or its derivatives （X2Ge=Si：, X=H, Me, F, Cl, Br, Ph, Ar, ...） and asymmetric π-bonded compounds are significant for the synthesis of small-ring involving Si and Ge and spiro-Si-heterocyclic ring compounds involving Ge.展开更多
The simultaneous diagonalization by congruence of pairs of Hermitian quaternion matrices is discussed. The problem is reduced to a parallel one on complex matrices by using the complex adjoint matrix related to each q...The simultaneous diagonalization by congruence of pairs of Hermitian quaternion matrices is discussed. The problem is reduced to a parallel one on complex matrices by using the complex adjoint matrix related to each quaternion matrix. It is proved that any two semi-positive definite Hermitian quaternion matrices can be simultaneously diagonalized by congruence.展开更多
Sm/TiCl4 system could well integrate the high reactivity of samarium（Ⅱ） and high deoxygenation capacity of low valent titanium within one system. In this paper, the intermolecular and intramolecular reductive coupl...Sm/TiCl4 system could well integrate the high reactivity of samarium（Ⅱ） and high deoxygenation capacity of low valent titanium within one system. In this paper, the intermolecular and intramolecular reductive coupling reactions of ketones with esters mediated by metallic samarium （Sm） and a catalytic amount of titanium tetrachloride （TiCl4） were successfully developed. A series of substituted ketones and cyclic β-keto-esters were prepared in moderate to good yields under reflux and neutral conditions.展开更多
AIM： To study the protective effects and mechanisms of Se-enriched lactobacillus on liver injury caused by carbon tetrachloride （CCl4） in mice. METHODS： Seventy-two ICR mice were randomly divided into four groups...AIM： To study the protective effects and mechanisms of Se-enriched lactobacillus on liver injury caused by carbon tetrachloride （CCl4） in mice. METHODS： Seventy-two ICR mice were randomly divided into four groups： normal group, CCl4-induced model group, low Se-enriched lactobacillus treatment group （L-Se group）, and high Se-enriched lactobacillus treatment group （H-Se group）. During a 3-wk experimental period, the common complete diet was orally provided daily for normal group and model group, and the mice in L-Se and H-Se groups were given a diet with 2 and 4 mg of organoselenium from Se-enriched lactobacillus per kg feed, respectively. From the 2nd wk of experiment, the model group, L-Se group, and H-Se group received abdominal cavity injection of olive oil solution containing 500 mL/L CCl4 （0.07 mL/100 g body mass） to induce liver injury, and the normal group was given olive oil on every other day for over 2 wk. In the first 2 wk post injection with CCl4, mice in each group were killed. The specimens of blood, liver tissue, and macrophages in abdominal cavity fluid were taken. Then the activities of the following liver tissue injury-associated enzymes including glutathione peroxidase （GSH-Px）, superoxide dismutase （SOD）, alanine aminotransferase （ALT） and aspartate aminotransferase （AST） as well as malondialdehyde （MDA） content were assayed. Changes of phagocytic rate and phagocytic index in macrophages were observed with Wright-Giemsa stain. Plasma TNF-α level was measured by radioimmunoassay. The level of intracellular free Ca^2＋ （[Ca^2＋]i） in hepatocytes was detected under a laser scanning confocal microscope. RESULTS： During the entire experimental period, the AST and ALT activities in liver were greatly enhanced by CCl4 and completely blunted by both low and high doses of Se-enriched lactobacillus. The Se-enriched lactobacillus- protected liver homogenate GSH-Px and SOD activities were higher or significantly higher than those in model group and were close to those in normal group. CCl4 significantly increased MDA content in liver homogenates, while administration of Se-enriched lactobacillus prevented MDA elevation. Phagocytic rate and phagocytic index of macrophages decreased after CCl4 treatment compared to those in normal control, but they were dramatically rescued by Se-enriched lactobacillus, showing a greatly higher phagocytic function compared to model group. CCl4 could significantly elevate plasma TNF-α and hepatocyte [Ca^2＋]i level, which were also obviously prevented by Se-enriched lactobacillus. CONCLUSION： Se-enriched lactobacillus can intervene in CCl4-induced liver injury in mice by enhancing macrophage function activity to keep normal and beneficial effects, elevating antioxidant-enzyme activities and reducing lipid peroxidation reaction, inhibiting excessive release of TNF-α, preventing the dramatic elevation of [Ca^2＋]i in hepatocytes.展开更多
The optical parameters for three samples of intrinsic, doped Si and doped Mg (Al x Ga 1- x ) y In 1- y P prepared by the MOCVD on GaAs substrate were measured by using ellipsometry and were calc...The optical parameters for three samples of intrinsic, doped Si and doped Mg (Al x Ga 1- x ) y In 1- y P prepared by the MOCVD on GaAs substrate were measured by using ellipsometry and were calculated by the two-layer absorption film model. The results obtained were discussed. The grown rates and thickness of oxidic layer on the intrinsic (Al x Ga 1- x ) y In 1- y P surface exposed in the atmosphere were studied. A linear dependence of oxidic layer thickness on the time was obtained.展开更多
In recent years,with the extensive applications of high performance computer and the rapid development of the attitude control of the spacecraft,quaternion theory has been widely used.Compared with Euler angles,quater...In recent years,with the extensive applications of high performance computer and the rapid development of the attitude control of the spacecraft,quaternion theory has been widely used.Compared with Euler angles,quaternion not only is simple calculation,but also can avoid the singularity problem of Euler angles,therefore it is widely used in the attitude control of spacecraft.In this paper,Simulink simulation technology is used to establish a rigid attitude simulation model with quaternion method and virtual reality scene by virtual reality modeling language(V RM L)is used to achieve attitude motion visualizationThe simulation results show that the Simulink simulation model can accurately reflect the attitude motion of the rigid body,which is valuable for the research of the attitude control of the spacecraft.展开更多
The organic-inorganic hybrid [(C14H18N2)(Pb2I6)]n ([C14H18N2]2+ = N,N?-1,4-buthy- lenedipyridinium (BDP)) with one-dimensional structure was self-assembling synthesized by the organic quaternary ammonium template. It ...The organic-inorganic hybrid [(C14H18N2)(Pb2I6)]n ([C14H18N2]2+ = N,N?-1,4-buthy- lenedipyridinium (BDP)) with one-dimensional structure was self-assembling synthesized by the organic quaternary ammonium template. It crystallizes in monoclinic, space group P21/n with a = 8.2596(9), b = 15.1363(19), c = 11.1603(13) , b = 97.915(5)o, C14H18N2Pb2I6, Mr = 1390.10, V = 1382.0(3) 3, Z = 2, Dc = 3.341 g/cm3, m(MoKa) = 18.870 mm-1, F(000) = 1196, the final R = 0.0420 and wR = 0.0921 for 2156 observed reflections with I > 2s(I). The title compound consists of cations ([C14H18N2]2+ ) and anion chain ([Pb2I62]n) which are combined by static attractive forces in the crystal.展开更多
A novel coordinated polymer [(C22H50N2)(Ag2I4)]n([C22H50N2]2+ = N,N?-1,2- ethylence-bis(N,N?-dimethyl octane ammonium) (EDO)) was synthesized by the reaction of AgI and EDO at room temperature with pH = 6.8, and struc...A novel coordinated polymer [(C22H50N2)(Ag2I4)]n([C22H50N2]2+ = N,N?-1,2- ethylence-bis(N,N?-dimethyl octane ammonium) (EDO)) was synthesized by the reaction of AgI and EDO at room temperature with pH = 6.8, and structurally characterized by means of X-ray single- crystal diffraction. It crystallizes in triclinic, space group P1 with a = 9.6080(1), b = 12.7643(2), c = 7.2157(8) ? a = 100.835(8), ?= 91.030(3), ? = 91.297(9)o, (C21.50H48.50Ag2I4N2), Mr = 1058.46, V = 868.71(19) 3, Z = 1, Dc = 2.023g/cm3, F(000) = 497.5, ?MoKa) = 4.692 mm-1, the final R = 0.0623 and wR = 0.1949 for 2641 observed reflections with I > 2s(I). The title compound consists of cations ([C22H50N2]2+) and anion chain (Ag2I42-)∞ which are combined by static attracting forces in the crystal to form the so-called organic-inorganic hybrid material.展开更多
A theoretical study is carried out on Gaunt＇s palladium-catalyzed selective C（sp3）-H activation of unprotected aliphatic amines. In this reaction, the methyl group is proposed to be activated through a four-membere...A theoretical study is carried out on Gaunt＇s palladium-catalyzed selective C（sp3）-H activation of unprotected aliphatic amines. In this reaction, the methyl group is proposed to be activated through a four-membered cyclometallation pathway even though an ethyl group is present in the substrate. Our calculation shows that the methyl and ethyl activation processes proceed in nitrogen-atom-directed pathway rather than carbonyl-directed one. More important, methyl activation is more favorable than ethyl activation with nitrogen atom as the directing group. Further studies on the structural parameters show that the lactone structure in cyclic substrate is the origin of the selective methyl activation. When the lactone moiety is changed to ketone, ether or alkyl, the selectivity could be reversed so that the ethyl activation becomes more favorable. This result validates the pro- oosal that lactone structure is key to selective methyl activation.展开更多
A series of Ti-Zr-Be-Fe bulk metallic glasses(BMGs)with good glass-forming ability(GFA)and high specific strength have been developed.With different alloying routes and content of Fe,it is found that these alloys exhi...A series of Ti-Zr-Be-Fe bulk metallic glasses(BMGs)with good glass-forming ability(GFA)and high specific strength have been developed.With different alloying routes and content of Fe,it is found that these alloys exhibit different GFA and mechanical properties.The effects of Fe addition on the GFA and mechanical properties of Ti-Zr-Be alloy are systemically investigated.The possible mechanisms for the improvement or damage to the GFA by addition of Fe can be interpreted in view of the mixing enthalpy,atomic size differences and electronegativity differences of the alloys,while the mechanical properties strongly depend on the Poisson’s ratio and free volume concentration.The experimental results also show that alloying technology is an effective method to improve the GFA and mechanical properties of Ti-Zr-Be glassy alloy.展开更多
文摘The H2Ge=Ge：, as well as and its derivatives （X2Ge=Ge：, X=H, Me, F, C1, Br, Ph, At, ...） is a kind of new species. Its cycloaddition reactions is a new area for the study of germylene chemistry. The mechanism of the cycloaddition reaction between singlet Me2Ge=Ge： and acetaldehyde was investigated with the B3LYP/6-31G＊ method in this work. From the potential energy profile, it could be predicted that the reaction has one dominant reaction pathway. The reaction rule is that the two reactants firstly form a four-membered Ge-heterocyclic ring germylene through the [2＋2] cycloaddition reaction. Because of the 4p unoccupied orbital of Ge： atom in the four-membered Ge-heterocyclic ring germylene and the ~ orbital of acetaldehyde forming a r^--~p donor-acceptor bond, the four-membered Ge-heterocyclic ring germylene further combines with acetaldehyde to form an intermedi- ate. Because the Ge atom in intermediate happens sp3 hybridization after transition state, then, intermediate isomerizes to a spiro-Ge-heterocyclic ring compound via a transition state. The research result indicates the laws of cycloaddition reaction between Me2Ge=Ge： and ac- etaldehyde, and lays the theory foundation of the cycloaddition reaction between H2Ge=Ge： and its derivatives （X2Ge=Ge：, X=H, Me, F, C1, Br, Ph, At, ...） and asymmetric ^-bonded compounds, which are significant for the synthesis of small-ring and spiro-Ge-heterocyclic ring compounds.
文摘H2Ge=Si： and its derivatives （X2Ge=Si：, X=H, Me, F, C1, Br, Ph, Ar, ...） are new species. Its cycloaddition reactions are new area for the study of silylene chemistry. The cycloaddition reaction mechanism of singlet H2Ge=Si： and formaldehyde has been investigated with the MP2/aug-cc-pVDZ method. From the potential energy profile, it could be predicted that the reaction has one dominant reaction pathway. The reaction rule is that two reactants firstly form a four-membered Ge-heterocyclic ring silylene through the [2＋2] cycloaddition reaction. Because of the 3p unoccupied orbital of Si： atom in the four-membered Ge-heterocyclic ring silylene and the π orbital of formaldehyde forming a π--p donor-acceptor bond, the four-membered Ge-heterocyclic ring silylene further combines with formaldehyde to form an intermediate. Because the Si： atom in the intermediate undergoes sp3 hybridization after transition state, then the intermediate isomerizes to a spiro-Si-heterocyclic ring compound involving Ge via a transition state. The result indicates the laws of cycloaddition reaction between H2Ge=Si： or its derivatives （X2Ge=Si：, X=H, Me, F, Cl, Br, Ph, Ar, ...） and asymmetric π-bonded compounds are significant for the synthesis of small-ring involving Si and Ge and spiro-Si-heterocyclic ring compounds involving Ge.
文摘The simultaneous diagonalization by congruence of pairs of Hermitian quaternion matrices is discussed. The problem is reduced to a parallel one on complex matrices by using the complex adjoint matrix related to each quaternion matrix. It is proved that any two semi-positive definite Hermitian quaternion matrices can be simultaneously diagonalized by congruence.
基金Project (No. 2004C21032) supported by the Key Technologies R &D Program of Zhejiang Province, China
文摘Sm/TiCl4 system could well integrate the high reactivity of samarium（Ⅱ） and high deoxygenation capacity of low valent titanium within one system. In this paper, the intermolecular and intramolecular reductive coupling reactions of ketones with esters mediated by metallic samarium （Sm） and a catalytic amount of titanium tetrachloride （TiCl4） were successfully developed. A series of substituted ketones and cyclic β-keto-esters were prepared in moderate to good yields under reflux and neutral conditions.
基金Supported by the Special Programs of State Science and Technology Ministry of China During the 10~(th) 5-Year Plan Period, No. 2002BA518 A12, and Open Foundation from Key Laboratory of Resource Biotechnology of Jiangsu Province, China, No. KJS00033
文摘AIM： To study the protective effects and mechanisms of Se-enriched lactobacillus on liver injury caused by carbon tetrachloride （CCl4） in mice. METHODS： Seventy-two ICR mice were randomly divided into four groups： normal group, CCl4-induced model group, low Se-enriched lactobacillus treatment group （L-Se group）, and high Se-enriched lactobacillus treatment group （H-Se group）. During a 3-wk experimental period, the common complete diet was orally provided daily for normal group and model group, and the mice in L-Se and H-Se groups were given a diet with 2 and 4 mg of organoselenium from Se-enriched lactobacillus per kg feed, respectively. From the 2nd wk of experiment, the model group, L-Se group, and H-Se group received abdominal cavity injection of olive oil solution containing 500 mL/L CCl4 （0.07 mL/100 g body mass） to induce liver injury, and the normal group was given olive oil on every other day for over 2 wk. In the first 2 wk post injection with CCl4, mice in each group were killed. The specimens of blood, liver tissue, and macrophages in abdominal cavity fluid were taken. Then the activities of the following liver tissue injury-associated enzymes including glutathione peroxidase （GSH-Px）, superoxide dismutase （SOD）, alanine aminotransferase （ALT） and aspartate aminotransferase （AST） as well as malondialdehyde （MDA） content were assayed. Changes of phagocytic rate and phagocytic index in macrophages were observed with Wright-Giemsa stain. Plasma TNF-α level was measured by radioimmunoassay. The level of intracellular free Ca^2＋ （[Ca^2＋]i） in hepatocytes was detected under a laser scanning confocal microscope. RESULTS： During the entire experimental period, the AST and ALT activities in liver were greatly enhanced by CCl4 and completely blunted by both low and high doses of Se-enriched lactobacillus. The Se-enriched lactobacillus- protected liver homogenate GSH-Px and SOD activities were higher or significantly higher than those in model group and were close to those in normal group. CCl4 significantly increased MDA content in liver homogenates, while administration of Se-enriched lactobacillus prevented MDA elevation. Phagocytic rate and phagocytic index of macrophages decreased after CCl4 treatment compared to those in normal control, but they were dramatically rescued by Se-enriched lactobacillus, showing a greatly higher phagocytic function compared to model group. CCl4 could significantly elevate plasma TNF-α and hepatocyte [Ca^2＋]i level, which were also obviously prevented by Se-enriched lactobacillus. CONCLUSION： Se-enriched lactobacillus can intervene in CCl4-induced liver injury in mice by enhancing macrophage function activity to keep normal and beneficial effects, elevating antioxidant-enzyme activities and reducing lipid peroxidation reaction, inhibiting excessive release of TNF-α, preventing the dramatic elevation of [Ca^2＋]i in hepatocytes.
文摘The optical parameters for three samples of intrinsic, doped Si and doped Mg (Al x Ga 1- x ) y In 1- y P prepared by the MOCVD on GaAs substrate were measured by using ellipsometry and were calculated by the two-layer absorption film model. The results obtained were discussed. The grown rates and thickness of oxidic layer on the intrinsic (Al x Ga 1- x ) y In 1- y P surface exposed in the atmosphere were studied. A linear dependence of oxidic layer thickness on the time was obtained.
基金Natural Science Foundation of Shanxi Province(No.201601D102002)
文摘In recent years,with the extensive applications of high performance computer and the rapid development of the attitude control of the spacecraft,quaternion theory has been widely used.Compared with Euler angles,quaternion not only is simple calculation,but also can avoid the singularity problem of Euler angles,therefore it is widely used in the attitude control of spacecraft.In this paper,Simulink simulation technology is used to establish a rigid attitude simulation model with quaternion method and virtual reality scene by virtual reality modeling language(V RM L)is used to achieve attitude motion visualizationThe simulation results show that the Simulink simulation model can accurately reflect the attitude motion of the rigid body,which is valuable for the research of the attitude control of the spacecraft.
基金This work was supported by the Foundation of Education Committee of Fujian Province (JB01020)
文摘The organic-inorganic hybrid [(C14H18N2)(Pb2I6)]n ([C14H18N2]2+ = N,N?-1,4-buthy- lenedipyridinium (BDP)) with one-dimensional structure was self-assembling synthesized by the organic quaternary ammonium template. It crystallizes in monoclinic, space group P21/n with a = 8.2596(9), b = 15.1363(19), c = 11.1603(13) , b = 97.915(5)o, C14H18N2Pb2I6, Mr = 1390.10, V = 1382.0(3) 3, Z = 2, Dc = 3.341 g/cm3, m(MoKa) = 18.870 mm-1, F(000) = 1196, the final R = 0.0420 and wR = 0.0921 for 2156 observed reflections with I > 2s(I). The title compound consists of cations ([C14H18N2]2+ ) and anion chain ([Pb2I62]n) which are combined by static attractive forces in the crystal.
基金This work was supported by the Foundation of Education Committee of Fujian Province (JB01020)
文摘A novel coordinated polymer [(C22H50N2)(Ag2I4)]n([C22H50N2]2+ = N,N?-1,2- ethylence-bis(N,N?-dimethyl octane ammonium) (EDO)) was synthesized by the reaction of AgI and EDO at room temperature with pH = 6.8, and structurally characterized by means of X-ray single- crystal diffraction. It crystallizes in triclinic, space group P1 with a = 9.6080(1), b = 12.7643(2), c = 7.2157(8) ? a = 100.835(8), ?= 91.030(3), ? = 91.297(9)o, (C21.50H48.50Ag2I4N2), Mr = 1058.46, V = 868.71(19) 3, Z = 1, Dc = 2.023g/cm3, F(000) = 497.5, ?MoKa) = 4.692 mm-1, the final R = 0.0623 and wR = 0.1949 for 2641 observed reflections with I > 2s(I). The title compound consists of cations ([C22H50N2]2+) and anion chain (Ag2I42-)∞ which are combined by static attracting forces in the crystal to form the so-called organic-inorganic hybrid material.
基金supported by the National Natural Science Foundation of China(21325208,21172209,21361140372,21202006)the National Basic Research Program of China(2012CB215306)+2 种基金Financial Resources Federal Credit Union(WK2060190025,WK2060190040,FRF-TP-14-015A2)Chinese Academy of Sciences(KJCX2-EW-J02)Program for Changjiang Scholars and Innovative Research Team and the supercomputer center of Shanghai and USTC
文摘A theoretical study is carried out on Gaunt＇s palladium-catalyzed selective C（sp3）-H activation of unprotected aliphatic amines. In this reaction, the methyl group is proposed to be activated through a four-membered cyclometallation pathway even though an ethyl group is present in the substrate. Our calculation shows that the methyl and ethyl activation processes proceed in nitrogen-atom-directed pathway rather than carbonyl-directed one. More important, methyl activation is more favorable than ethyl activation with nitrogen atom as the directing group. Further studies on the structural parameters show that the lactone structure in cyclic substrate is the origin of the selective methyl activation. When the lactone moiety is changed to ketone, ether or alkyl, the selectivity could be reversed so that the ethyl activation becomes more favorable. This result validates the pro- oosal that lactone structure is key to selective methyl activation.
基金supported by the National Basic Research Program of China(Grant No.2007CB613905)the National Natural Science Foundation of China(Grant Nos.51271095,51101090 and 50971073)
文摘A series of Ti-Zr-Be-Fe bulk metallic glasses(BMGs)with good glass-forming ability(GFA)and high specific strength have been developed.With different alloying routes and content of Fe,it is found that these alloys exhibit different GFA and mechanical properties.The effects of Fe addition on the GFA and mechanical properties of Ti-Zr-Be alloy are systemically investigated.The possible mechanisms for the improvement or damage to the GFA by addition of Fe can be interpreted in view of the mixing enthalpy,atomic size differences and electronegativity differences of the alloys,while the mechanical properties strongly depend on the Poisson’s ratio and free volume concentration.The experimental results also show that alloying technology is an effective method to improve the GFA and mechanical properties of Ti-Zr-Be glassy alloy.
