Increasing the population and infrastructure in both emerging and developed countries requires a considerable amount of cement, which significantly affects the environment. The primary materials of concrete (‘cement...Increasing the population and infrastructure in both emerging and developed countries requires a considerable amount of cement, which significantly affects the environment. The primary materials of concrete (‘cement’) production emit a large quantity of CO<sub>2</sub> into the environment. Also, the cost of conventional building materials like cement gives motivation to find geopolymer waste materials for concrete. To reduce harmful effects on the environment and cost of traditional concrete substance, alternative waste materials like rice husk ash (RHA), ground granulated blast-furnace (GGBS), fly ash (FA), and metakaolin (MK) can be used due to their pozzolanic behavior. RHA waste material with a high silica concentration obtained from burning rice husks can possibly be used as a supplementary cementitious material (SCM) in the manufacturing of concrete, and its strong pozzolanic properties can contribute to the strength and impermeability of concrete. This review paper highlights a summary of the positive effect of using RHA as a partial substitute for cement in building construction, as well as its optimal inclusion of enhanced mechanical properties like compressive strength, flexural strength, and split tensile strength of mortar and concrete.展开更多
Two new 2D coordination polymers, [Zn（HL）（Hbpp）]n （1） mid [Cd（HL）（Hbpp）（H2O）]n （2） （H4L = 1,3-di（2,4-dicarboxyphenyl） benzene, bpp = 1,3-di（4-pyridyl）propane）, have been hydrothermally synthesized ...Two new 2D coordination polymers, [Zn（HL）（Hbpp）]n （1） mid [Cd（HL）（Hbpp）（H2O）]n （2） （H4L = 1,3-di（2,4-dicarboxyphenyl） benzene, bpp = 1,3-di（4-pyridyl）propane）, have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, elemental analysis, TGA and 1R spectroscopy. Complex 1 crystallizes in monoclinic, space group P21/n, with a = 13.1031（6）, b = 14.7315（7）, c = 15.0041（7） A, β = 91.202（1）°, V= 2895.6（2） A3, Dc = 1.532 g/cm3, Mr = 667.97, F（000） = 1376.0, μ = 0.909 mm-1, Z = 4, the final R = 0.0481 and wR = 0.1304 for 7027 observed reflections with 1 〉 2a（/）. Complex 2 also belongs to the monoclinic space group P2Jn, with a = 13.6326（4）, b = 14.6432（4）, c = 14.9395（5）A, β = 93.132（1）°, V= 2977.84（16） A3, D, = 1.613 g/cm3, ）14,. = 1445.98, F（000） = 733.0,/1 = 0.794 mm-1, Z = 2, the final R = 0.0283 and wR = 0.0784 for 7230 observed reflections with I 〉 2σ（I）. Both complexes 1 and 2 form 2D net structures, which are further linked to form 3D supramolecular net structures via intermolecular hydrogen bonds and aromatic π-π stacking interactions.展开更多
The title complex [Cd（IPA）L（H2O）]n（1,H2IPA = isophthalic acid,L = 1,4-bis（pyra-zole-1-ylmethyl）benzene） has been hydrothermally synthesized,and characterized by elemental analyses,IR spectroscopy,TGA and X-ray...The title complex [Cd（IPA）L（H2O）]n（1,H2IPA = isophthalic acid,L = 1,4-bis（pyra-zole-1-ylmethyl）benzene） has been hydrothermally synthesized,and characterized by elemental analyses,IR spectroscopy,TGA and X-ray single-crystal diffraction.It crystallizes in the triclinic system,space group P1 with a = 9.3060（6）,b = 10.2374（7）,c = 11.9706（8） ？,α = 73.804（6）,β = 77.883（5）,γ = 85.942（5）°,V = 1070.7（1） ？3,Z = 2,C22H20CdN4O5,Mr = 532.82,Dc = 1.653 g/cm3,μ = 1.062 mm-1,λ（MoKα） = 0.71073 ？,F（000） = 536,R = 0.0392 and wR = 0.0640 for 3751 observed reflections with I 2σ（I）.Crystal structure analysis showed that complex 1 has a 1D double chain structure,which is assembled together through strong O-H...O hydrogen bonding interactions between coordinated water molecules and carboxylate groups of isophthalate to form a 2D supramolecular network.In addition,the solid-state fluorescent spectrum of 1 exhibits strong emission at 364 nm.展开更多
Two Co（Ⅱ） coordination polymers, namely [Co（L）Cl]n（1） and [Co（L）（CH3 COO）]n（2）, {HL = 3,5-di（4 H-1,2,4-triazole-4-yl）benzoic acid}, were synthesized under hydrothermal conditions. Compound 1 crystallize...Two Co（Ⅱ） coordination polymers, namely [Co（L）Cl]n（1） and [Co（L）（CH3 COO）]n（2）, {HL = 3,5-di（4 H-1,2,4-triazole-4-yl）benzoic acid}, were synthesized under hydrothermal conditions. Compound 1 crystallizes in orthorhombic system, space group Pmma with a = 7.032（5）, b = 11.555（8）, c = 8.185（5） A, V = 665.1（7） А3, Z = 2, Dc = 1.746 g/cm3, F（000） = 350, Mr = 349.61, μ = 1.504 mm（-1）, the final R = 0.0568 and w R = 0.1739 for 2312 observed reflections with I 2σ（I）. Compound 2 crystallizes in orthorhombic system, space group Pmma with a = 7.7505（17）, b = 11.391（3）, c = 8.0298（18） A, V = 708.9（3） A3, Z = 2, Dc = 1.748 g/cm3, F（000） = 378, Mr = 373.20, μ = 1.245 mm-1, the final R = 0.0350 and w R = 0.0873 for 5239 observed reflections with I 2σ（I）. Single-crystal X-ray analyses revealed that complexes 1 and 2 exhibit similar 2 D layer structures with uncoordinated carboxyl as dangling arms. The neighboring layers are further connected by these arms, leading to interest 2 D → 3 D polythreading frameworks. Moreover, the magnetic susceptibility study indicates compound 1 exhibits antiferromagnetic behavior.展开更多
The perylene （C20H12） layer effect on the electrical and dielectric properties of Al/p-Si （MS） and Al/perylene/p-Si （MPS） diodes have been investigated and compared in the frequency range of 0.7 kHz-2 MHz. Exper...The perylene （C20H12） layer effect on the electrical and dielectric properties of Al/p-Si （MS） and Al/perylene/p-Si （MPS） diodes have been investigated and compared in the frequency range of 0.7 kHz-2 MHz. Experimental results show that C-V characteristics give an anomalous peak for two structures at low frequencies due to interface states （Nss） and series resistance （Rs）. The increases in C and G/o3 at low frequencies confirm that the charges at interface can easily follow an ac signal and yield excess capacitance and conductance. The frequency-dependent dielectric constant （er） and dielectric loss （e＇） are subtracted using C and G/co data at 1.5 V. The eI and e＂ values are found to be strongly dependent on frequency and voltage, and their large values at low frequencies can be attributed to the excess polarization coming from charges at traps. Plots of ln（o＇ac）-ln（w） for two structures have two linear regions, with slopes of 0.369 and 1.166 for MS, and of 0.077 and 1.061 for MPS, respectively. From the C 2-V characteristics, the doping acceptor atom concentration （NA） and barrier height （,~） for Schottky barrier diodes （SBDs） 1.303 ~ 1015 cm-3, and 1.10 and I. 13 eV, respectively. of MS and MPS types are also obtained to be 1.484 ~ 1015展开更多
The theoretical linear solvation energy relationship(TLSER) approach was adopted to predict the aqueous solubility and n -octanol/water partition coefficient of three groups of environmentally important chemicals-poly...The theoretical linear solvation energy relationship(TLSER) approach was adopted to predict the aqueous solubility and n -octanol/water partition coefficient of three groups of environmentally important chemicals-polychlorinated biphenyls(PCBs), polychlorinated dibenzodioxins and dibenzofurans(PCDDs and PCDFs). For each compound, five quantum parameters were calculated using AM1 semiempirical molecular orbital methods and used as structure descriptors: average molecular polarizability(α), energy of the lowest unoccupied molecular orbit( E _ LUMO ), energy of the highest occupied molecular orbit( E _ HOMO ), the most positive charge on a hydrogen atom( q _+), and the most negative atomic partial charge( q _-) in the solute molecule. Then standard independent variables in TLSER equation was extracted and two series of quantitative equations between these quantum parameters and aqueous solubility and n -octanol/water partition coefficient were obtained by stepwise multiple linear regression(MLR) method. The developed equations have both quite high accuracy and explicit meanings. And the cross-validation test illustrated the good predictive power and stability of the established models. The results showed that TLSER could be used as a promising approach in the estimation of partition and solubility properties of macromolecular chemicals, such as persistent organic pollutants.展开更多
Zinc oxide is recently being used as a magnetic semiconductor with the introduction of mag-netic elements.In this work,we report phase pure synthesis of Mg and Ni co-substituted ZnO to explore its structure,optical,ma...Zinc oxide is recently being used as a magnetic semiconductor with the introduction of mag-netic elements.In this work,we report phase pure synthesis of Mg and Ni co-substituted ZnO to explore its structure,optical,magnetic and photo-catalytic properties.X-ray di raction analysis reveals the hexagonal wurtzite type structure having P63mc space group without any impurity phase.UV-Vis spectrophotometry demonstrates the variation in bandgap with the addition of Mg and Ni content in ZnO matrix.Magnetic measurements exhibit a clear boosted magnetization in Ni and Mg co-doped compositions with its stable value of bandgap corroborating the structural stability and magnetic tuning for its advanced applications in modern-day spintronic devices.Photo-catalytic measurements performed using methyl green degradation demonstrate an enhanced trend of activity in Mg and Ni co-doped compositions.展开更多
The relationship between some smoothness and weak asymptotic-norming properties of dual Banach space X is studied. The main results are the following. Suppose that X is weakly sequential complete Banach space, then X...The relationship between some smoothness and weak asymptotic-norming properties of dual Banach space X is studied. The main results are the following. Suppose that X is weakly sequential complete Banach space, then X is Frechet differentiable if and only if X has B （X）- ANP -I, X is quasi-Frechet differentiable if and only if X has B（X）- ANP -H and X is very smooth if and only if X has B（X）- ANP -Ⅱ. A new local asymptotic-norming property is also introduced, and the relationship among this one and other local asymptotic-norming properties and some topological properties is discussed. In addition, this paper gives a negative answer to the open question raised by Hu and Lin in Bull. Austral. Math. Soc,45,1992.展开更多
The surface heterogeneity of two samples of montmorillonite clays from Katiola (C?te d’Ivoire), referenced K1 and K2, has been explored by low-pressure of argon and nitrogen adsorption at 77 K. The adsorption isother...The surface heterogeneity of two samples of montmorillonite clays from Katiola (C?te d’Ivoire), referenced K1 and K2, has been explored by low-pressure of argon and nitrogen adsorption at 77 K. The adsorption isotherms of the studied samples have been modelled by the Derivative Isotherms Summation method (DIS method) in a satisfactory manner, with the help of local isotherms to argon and nitrogen. The use of the DIS method allowed us to quantify the basal and lateral surfaces, then to determine the total surface of studied materials. Beyond the quantitative aspect, the DIS method permitted us to determine the lamellarity index of the clay grains and to describe the two studied samples of a family of high energy site (–14 kT to nitrogen), that shows a strong affinity for the polar adsorbates.展开更多
The suitable test equipment for wire-drawing was designed. Wire-drawing tests were carried on with this equipment for TiC/Al2O3 ceramic wire-drawing die. Effect of lubrication medium and drawing velocity on the drawin...The suitable test equipment for wire-drawing was designed. Wire-drawing tests were carried on with this equipment for TiC/Al2O3 ceramic wire-drawing die. Effect of lubrication medium and drawing velocity on the drawing force was investigated. The wear mechanisms of the ceramic drawing dies were investigated. Worn bore surfaces of the ceramic drawing dies were examined by scanning electron microscopy. The results show that lubricant media have great influence on the drawing force. The drawing force is the smallest when a grease lubricant is used. But alteration of drawing velocity has scarcely any influence on the drawing force. Detailed observations and analyses of the die wear surface reveal that the most common failure of the ceramic drawing die is the wear in the invariable zone and bearing zone owing to the greater press stresses. Abrasive and adhesive wear are found to be the predominant wear mechanisms for ceramic drawing die.展开更多
文摘Increasing the population and infrastructure in both emerging and developed countries requires a considerable amount of cement, which significantly affects the environment. The primary materials of concrete (‘cement’) production emit a large quantity of CO<sub>2</sub> into the environment. Also, the cost of conventional building materials like cement gives motivation to find geopolymer waste materials for concrete. To reduce harmful effects on the environment and cost of traditional concrete substance, alternative waste materials like rice husk ash (RHA), ground granulated blast-furnace (GGBS), fly ash (FA), and metakaolin (MK) can be used due to their pozzolanic behavior. RHA waste material with a high silica concentration obtained from burning rice husks can possibly be used as a supplementary cementitious material (SCM) in the manufacturing of concrete, and its strong pozzolanic properties can contribute to the strength and impermeability of concrete. This review paper highlights a summary of the positive effect of using RHA as a partial substitute for cement in building construction, as well as its optimal inclusion of enhanced mechanical properties like compressive strength, flexural strength, and split tensile strength of mortar and concrete.
基金Supported by the National Natural Science Foundation of China(No.21373178)the Open Foundation of Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education(338080043)the Natural Scientific Research Foundation of Shaanxi Provincial Education Office of China(No.13JS124)
文摘Two new 2D coordination polymers, [Zn（HL）（Hbpp）]n （1） mid [Cd（HL）（Hbpp）（H2O）]n （2） （H4L = 1,3-di（2,4-dicarboxyphenyl） benzene, bpp = 1,3-di（4-pyridyl）propane）, have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, elemental analysis, TGA and 1R spectroscopy. Complex 1 crystallizes in monoclinic, space group P21/n, with a = 13.1031（6）, b = 14.7315（7）, c = 15.0041（7） A, β = 91.202（1）°, V= 2895.6（2） A3, Dc = 1.532 g/cm3, Mr = 667.97, F（000） = 1376.0, μ = 0.909 mm-1, Z = 4, the final R = 0.0481 and wR = 0.1304 for 7027 observed reflections with 1 〉 2a（/）. Complex 2 also belongs to the monoclinic space group P2Jn, with a = 13.6326（4）, b = 14.6432（4）, c = 14.9395（5）A, β = 93.132（1）°, V= 2977.84（16） A3, D, = 1.613 g/cm3, ）14,. = 1445.98, F（000） = 733.0,/1 = 0.794 mm-1, Z = 2, the final R = 0.0283 and wR = 0.0784 for 7230 observed reflections with I 〉 2σ（I）. Both complexes 1 and 2 form 2D net structures, which are further linked to form 3D supramolecular net structures via intermolecular hydrogen bonds and aromatic π-π stacking interactions.
文摘The title complex [Cd（IPA）L（H2O）]n（1,H2IPA = isophthalic acid,L = 1,4-bis（pyra-zole-1-ylmethyl）benzene） has been hydrothermally synthesized,and characterized by elemental analyses,IR spectroscopy,TGA and X-ray single-crystal diffraction.It crystallizes in the triclinic system,space group P1 with a = 9.3060（6）,b = 10.2374（7）,c = 11.9706（8） ？,α = 73.804（6）,β = 77.883（5）,γ = 85.942（5）°,V = 1070.7（1） ？3,Z = 2,C22H20CdN4O5,Mr = 532.82,Dc = 1.653 g/cm3,μ = 1.062 mm-1,λ（MoKα） = 0.71073 ？,F（000） = 536,R = 0.0392 and wR = 0.0640 for 3751 observed reflections with I 2σ（I）.Crystal structure analysis showed that complex 1 has a 1D double chain structure,which is assembled together through strong O-H...O hydrogen bonding interactions between coordinated water molecules and carboxylate groups of isophthalate to form a 2D supramolecular network.In addition,the solid-state fluorescent spectrum of 1 exhibits strong emission at 364 nm.
基金supported by the National Natural Science Foundation of China(21372112)
文摘Two Co（Ⅱ） coordination polymers, namely [Co（L）Cl]n（1） and [Co（L）（CH3 COO）]n（2）, {HL = 3,5-di（4 H-1,2,4-triazole-4-yl）benzoic acid}, were synthesized under hydrothermal conditions. Compound 1 crystallizes in orthorhombic system, space group Pmma with a = 7.032（5）, b = 11.555（8）, c = 8.185（5） A, V = 665.1（7） А3, Z = 2, Dc = 1.746 g/cm3, F（000） = 350, Mr = 349.61, μ = 1.504 mm（-1）, the final R = 0.0568 and w R = 0.1739 for 2312 observed reflections with I 2σ（I）. Compound 2 crystallizes in orthorhombic system, space group Pmma with a = 7.7505（17）, b = 11.391（3）, c = 8.0298（18） A, V = 708.9（3） A3, Z = 2, Dc = 1.748 g/cm3, F（000） = 378, Mr = 373.20, μ = 1.245 mm-1, the final R = 0.0350 and w R = 0.0873 for 5239 observed reflections with I 2σ（I）. Single-crystal X-ray analyses revealed that complexes 1 and 2 exhibit similar 2 D layer structures with uncoordinated carboxyl as dangling arms. The neighboring layers are further connected by these arms, leading to interest 2 D → 3 D polythreading frameworks. Moreover, the magnetic susceptibility study indicates compound 1 exhibits antiferromagnetic behavior.
文摘The perylene （C20H12） layer effect on the electrical and dielectric properties of Al/p-Si （MS） and Al/perylene/p-Si （MPS） diodes have been investigated and compared in the frequency range of 0.7 kHz-2 MHz. Experimental results show that C-V characteristics give an anomalous peak for two structures at low frequencies due to interface states （Nss） and series resistance （Rs）. The increases in C and G/o3 at low frequencies confirm that the charges at interface can easily follow an ac signal and yield excess capacitance and conductance. The frequency-dependent dielectric constant （er） and dielectric loss （e＇） are subtracted using C and G/co data at 1.5 V. The eI and e＂ values are found to be strongly dependent on frequency and voltage, and their large values at low frequencies can be attributed to the excess polarization coming from charges at traps. Plots of ln（o＇ac）-ln（w） for two structures have two linear regions, with slopes of 0.369 and 1.166 for MS, and of 0.077 and 1.061 for MPS, respectively. From the C 2-V characteristics, the doping acceptor atom concentration （NA） and barrier height （,~） for Schottky barrier diodes （SBDs） 1.303 ~ 1015 cm-3, and 1.10 and I. 13 eV, respectively. of MS and MPS types are also obtained to be 1.484 ~ 1015
基金TheNationalKeyBasicResearchFoundationofChina (No .G1 9990 4 571 1 )
文摘The theoretical linear solvation energy relationship(TLSER) approach was adopted to predict the aqueous solubility and n -octanol/water partition coefficient of three groups of environmentally important chemicals-polychlorinated biphenyls(PCBs), polychlorinated dibenzodioxins and dibenzofurans(PCDDs and PCDFs). For each compound, five quantum parameters were calculated using AM1 semiempirical molecular orbital methods and used as structure descriptors: average molecular polarizability(α), energy of the lowest unoccupied molecular orbit( E _ LUMO ), energy of the highest occupied molecular orbit( E _ HOMO ), the most positive charge on a hydrogen atom( q _+), and the most negative atomic partial charge( q _-) in the solute molecule. Then standard independent variables in TLSER equation was extracted and two series of quantitative equations between these quantum parameters and aqueous solubility and n -octanol/water partition coefficient were obtained by stepwise multiple linear regression(MLR) method. The developed equations have both quite high accuracy and explicit meanings. And the cross-validation test illustrated the good predictive power and stability of the established models. The results showed that TLSER could be used as a promising approach in the estimation of partition and solubility properties of macromolecular chemicals, such as persistent organic pollutants.
基金supported by the Deanship of Scienti c Research at King Saud University for funding under Research Group(No.RG1440-021).
文摘Zinc oxide is recently being used as a magnetic semiconductor with the introduction of mag-netic elements.In this work,we report phase pure synthesis of Mg and Ni co-substituted ZnO to explore its structure,optical,magnetic and photo-catalytic properties.X-ray di raction analysis reveals the hexagonal wurtzite type structure having P63mc space group without any impurity phase.UV-Vis spectrophotometry demonstrates the variation in bandgap with the addition of Mg and Ni content in ZnO matrix.Magnetic measurements exhibit a clear boosted magnetization in Ni and Mg co-doped compositions with its stable value of bandgap corroborating the structural stability and magnetic tuning for its advanced applications in modern-day spintronic devices.Photo-catalytic measurements performed using methyl green degradation demonstrate an enhanced trend of activity in Mg and Ni co-doped compositions.
基金National Natural Science Foundation of China(10671118) the Natural Science Foundation of Shanghai Education Committee (06NZ016)
文摘The relationship between some smoothness and weak asymptotic-norming properties of dual Banach space X is studied. The main results are the following. Suppose that X is weakly sequential complete Banach space, then X is Frechet differentiable if and only if X has B （X）- ANP -I, X is quasi-Frechet differentiable if and only if X has B（X）- ANP -H and X is very smooth if and only if X has B（X）- ANP -Ⅱ. A new local asymptotic-norming property is also introduced, and the relationship among this one and other local asymptotic-norming properties and some topological properties is discussed. In addition, this paper gives a negative answer to the open question raised by Hu and Lin in Bull. Austral. Math. Soc,45,1992.
文摘The surface heterogeneity of two samples of montmorillonite clays from Katiola (C?te d’Ivoire), referenced K1 and K2, has been explored by low-pressure of argon and nitrogen adsorption at 77 K. The adsorption isotherms of the studied samples have been modelled by the Derivative Isotherms Summation method (DIS method) in a satisfactory manner, with the help of local isotherms to argon and nitrogen. The use of the DIS method allowed us to quantify the basal and lateral surfaces, then to determine the total surface of studied materials. Beyond the quantitative aspect, the DIS method permitted us to determine the lamellarity index of the clay grains and to describe the two studied samples of a family of high energy site (–14 kT to nitrogen), that shows a strong affinity for the polar adsorbates.
基金Project(B0614) supported by the Natural Science Foundation of University of Jinan, ChinaProject(20030422105) supported by the Specialized Research Fund for Doctoral Program of Higher Education, China+1 种基金Project(Y2004F08) supported by the Natural Science Foundation of Shandong Province, ChinaProject(NCET-04-0622) supported by the Program for New Century Excellent Talents in University, China.
文摘The suitable test equipment for wire-drawing was designed. Wire-drawing tests were carried on with this equipment for TiC/Al2O3 ceramic wire-drawing die. Effect of lubrication medium and drawing velocity on the drawing force was investigated. The wear mechanisms of the ceramic drawing dies were investigated. Worn bore surfaces of the ceramic drawing dies were examined by scanning electron microscopy. The results show that lubricant media have great influence on the drawing force. The drawing force is the smallest when a grease lubricant is used. But alteration of drawing velocity has scarcely any influence on the drawing force. Detailed observations and analyses of the die wear surface reveal that the most common failure of the ceramic drawing die is the wear in the invariable zone and bearing zone owing to the greater press stresses. Abrasive and adhesive wear are found to be the predominant wear mechanisms for ceramic drawing die.
