By pattern recognition chemical bond parameter method, the formability of NaZn<sub>13</sub> type and BaCd<sub>11</sub> type ternary compounds in RE-M Si （RE=La-Lu, M is any metallic element） ...By pattern recognition chemical bond parameter method, the formability of NaZn<sub>13</sub> type and BaCd<sub>11</sub> type ternary compounds in RE-M Si （RE=La-Lu, M is any metallic element） systems has been investigated. And the existence of unknown ternary compounds is predicted by the pattern recognition method.展开更多
A D-type photonic crystal fiber(PCF) sensor based on surface plasmon resonance(SPR) principle is designed.In order to excite the SPR effect,a gold film is plated on the open-loop channel of the sensor,the free electro...A D-type photonic crystal fiber(PCF) sensor based on surface plasmon resonance(SPR) principle is designed.In order to excite the SPR effect,a gold film is plated on the open-loop channel of the sensor,the free electrons in a metal are resonated with photons.The structural parameters are fine-tuned and the sensing performance of the sensor is studied.The results show that the maximum spectral sensitivity reaches 18 000 nm/RIU in the refractive index range of 1.24—1.32,and the maximum resolution is 5.56×10^(-6) RIU.The novel structure with high sensitivity and low refractive index provides a new perspective for fluid density detection.展开更多
We have used chemical bond parameters and pattern recognition method to investigatethe regularities of the crystal type of alloy phase,and achieved good results.Theparameters used,however,are semi-empirical paramters,...We have used chemical bond parameters and pattern recognition method to investigatethe regularities of the crystal type of alloy phase,and achieved good results.Theparameters used,however,are semi-empirical paramters,which are not very strict fromtheoretical viewpoint.In this letter,we use the numbers describing atomic structure(thenumbers of valence electrons Z<sub>1</sub>,Z<sub>2</sub>,the principal quantum numbers of valence electrons n<sub>1</sub>,展开更多
In this work, the mesophase properties were tuned via mixing two discotic molecules with structural complementarity. Compared with the liquid crystalline hexakis（n-hexyloxy）triphenylene（H6TP）materials（columnar he...In this work, the mesophase properties were tuned via mixing two discotic molecules with structural complementarity. Compared with the liquid crystalline hexakis（n-hexyloxy）triphenylene（H6TP）materials（columnar hexagonal phase from 53 ℃ to 91 ℃）, mesophase types as well as phase transition temperatures varied with the introduction of crystalline hexaazatriphenylene derivative（PBH）molecules. The introduction of less than 33% amount of PBH disrupted the columnar hexagonal phase formed by H6 TP remarkably, followed by the decreased clearing temperatures of liquid crystals. As the PBH amount was further increased, the destroyed columnar hexagonal phase was turned into the columnar rectangular phase, in which H6 TP and PBH molecules together formed the columnar mesophase. The formation of new mesophase contributed to the enlarged mesophase temperature（from44 ℃ to 144 ℃）. We speculated that the alkyl chains interaction induced by the PBH component competed with the strong p–p stacking between H6 TP molecules, thus altering the liquid crystalline properties including mesophase types and phase transition temperatures.展开更多
The positron lifetimes of some compounds with NaCl-type crystal structure are calculated with the method of atomic superposition approximation （ATSUP） based on the theories of local-density-approximation （LDA） and...The positron lifetimes of some compounds with NaCl-type crystal structure are calculated with the method of atomic superposition approximation （ATSUP） based on the theories of local-density-approximation （LDA） and general- gradient-approximation （GGA）. The systematical results are fitted to a curve as a function of lattice constants. The positron bulk lifetimes of some other compounds with NaCl-type crystal structure, which are deduced from the systematical results, are in agreement with the experimental results given in other literature.展开更多
The compound [Cd（L）2（NO3）]NO3·0.5H2O （L = N-benzyl-2-（quinolin-8-yloxy）aceta- mide） 1 has been synthesized and structurally determined by single-crystal X-ray diffraction, elemental analysis, IR and UV sp...The compound [Cd（L）2（NO3）]NO3·0.5H2O （L = N-benzyl-2-（quinolin-8-yloxy）aceta- mide） 1 has been synthesized and structurally determined by single-crystal X-ray diffraction, elemental analysis, IR and UV spectroscopy. The crystal belongs to the triclinic system, space group P1 with a = 11.7175（13）, b = 11.8873（13）, c = 14.0958（16） A, α = 74.889（2）, β= 78.228（2）, γ = 78.831（2）°, V= 1835.0（4） A3, Z= 1, Dc= 1.502 Mg/m3, Mr = 1660.17,μ = 0.662 mm-1, F（000） = 846, 2（MoKa） = 0.71073 A, the final R = 0.0585 and wR = 0.0577 for all observed reflections. The results show that the Cd（II） ion with a square antiprismatic geometry is coordinated by a N206 donor set, two NO2 sets from two ligands and two O atoms from a bidendate nitrate group. In the crystal, the O-H...O and N-H...O hydrogen bonds are helpful to consolidate the three- dimensional network.展开更多
A folding beam-type piezoelectric phononic crystal model is proposed to isolate vibration. Two piezoelectric bimorphs are joined by two masses as a folding structure to comprise each unit cell of the piezoelectric pho...A folding beam-type piezoelectric phononic crystal model is proposed to isolate vibration. Two piezoelectric bimorphs are joined by two masses as a folding structure to comprise each unit cell of the piezoelectric phononic crystal. Each bimorph is connected independently by a resistive-inductive resonant shunting circuit. The folding structure extends the propagation path of elastic waves, while its structure size remains quite small. Propagation of coupled extension-flexural elastic waves is studied by the classical laminated beam theory and transfer matrix method. The theoretical model is further verified with the finite element method(FEM). The effects of geometrical and circuit parameters on the band gaps are analyzed. With only 4 unit cells, the folding beam-type piezoelectric phononic crystal generates two Bragg band gaps of 369 Hz to1 687 Hz and 2 127 Hz to 4 000 Hz. In addition, between these two Bragg band gaps, a locally resonant band gap is induced by resonant shunting circuits. Appropriate circuit parameters are used to join these two Bragg band gaps by the locally resonant band gap.Thus, a low-frequency and broad band gap of 369 Hz to 4 000 Hz is obtained.展开更多
A new series of chiral shish-kebab type liquid crystal block copolymers that form the smectic C(Sc*) phase was synthesized by solution polycondensation. The copolymers were characterized by GPC, DSC, TG, POM, X-ray di...A new series of chiral shish-kebab type liquid crystal block copolymers that form the smectic C(Sc*) phase was synthesized by solution polycondensation. The copolymers were characterized by GPC, DSC, TG, POM, X-ray diffraction and polarimeter. The copolymers 7 entered into liquid crystal phase whin they were heated to their melting temperatures (T-m) and the copolymers 8 were in liquid crystal phase at room temperature with low viscosities. The smectic sanded texture or focal-conic texture were observed on POM. All the chiral block copolymers showed high optical activity. No racemization has happened. Temperature-variable X-ray diffraction study together with POM and polarimetric analysis realized that they are chiral smectic C(Sc*) phase. Thus we offer in this report the first example of shish-kebab type liquid crystal block copolymers that form a chiral smectic C(Sc*) phase. The variation of melting and isotropization temperatures with molecular structure was also discussed.展开更多
Reaction crystallization of struvite in water solutions containing 0.20 mass % of phosphate(V) ions by magnesium and ammonium ions addition was investigated experimentally. Process was carried out in DTM type crystall...Reaction crystallization of struvite in water solutions containing 0.20 mass % of phosphate(V) ions by magnesium and ammonium ions addition was investigated experimentally. Process was carried out in DTM type crystallizer with liquid jet pump device in 298 K assuming stoichiometric conditions. Struvite crystals of mean size Lm 5.2-23.0 μm were produced depending on pH (9-11) and mean residence time of suspension in a crystallizer τ (900-3600 s). Under these conditions linear growth rate of struvite crystals (SIG MSMPR kinetic model) decreased 2-time with the increase in pH and 3-time with the elongation of mean residence time of crystal suspension from 7.11×10-9 m/s (pH 9, τ900 s) to 1.65×10-9 m/s (pH 11, τ3600 s). Nucleation rate varied within the 7.9×108-1.8×1010 1/(sm3) limits. Struvite product of maximal linear size exceeded 100 μm with 10 vol. % of < 3 μm fraction corresponded to pH 9 and τ3600 s.展开更多
1 Introduction Calcium sulfate deposition is one of the most important and serious problems faced by heat transfer equipment during operation(Pavlos et al.,1999;Liu et al.,1996).The crystallization of calcium sulfate ...1 Introduction Calcium sulfate deposition is one of the most important and serious problems faced by heat transfer equipment during operation(Pavlos et al.,1999;Liu et al.,1996).The crystallization of calcium sulfate is known as a major展开更多
1 Introduction There exist calcium and sulfate ions outside sodium chloride in solution mining for calcium sulfate brine.The calcium and sulfate ions not only affect the purity of the vacuum salt products,but also inc...1 Introduction There exist calcium and sulfate ions outside sodium chloride in solution mining for calcium sulfate brine.The calcium and sulfate ions not only affect the purity of the vacuum salt products,but also increase the scaling of vacuum evaporation tanks and brine reusing pipes.Additives have certain impacts on the crystallization dynamics(Randolph et al.,1971).The crystallization展开更多
The crystal structure and magnetic properties of SmFeg_xCox （x = 0, 1, 3, 5） alloys were studied by X-ray powder diffraction （XRD） and magnetic measurements. The Th2Znl7-type structure of the as-cast state is chan...The crystal structure and magnetic properties of SmFeg_xCox （x = 0, 1, 3, 5） alloys were studied by X-ray powder diffraction （XRD） and magnetic measurements. The Th2Znl7-type structure of the as-cast state is changed to TbCu7-type structure after quenching to a rotating molybdenum roll under certain velocity （12, 20, and 32 m.s-l）. The （002） XRD peak appears and ^-Fe phase disappears when the Co is added up to x = 5. Saturation magnetization of SmFe9 under different temperature shows 9 % change （112-102 A.m2.g-1） when the temperature is higher than 200 K. The saturation magnetization is 115 A.m2.g-1 and coercivity is 0.304 T at 5 K for SmFe9 alloys. Increased saturation magnetization and decreased coercivity can be obtained for Co added up to x = 5 at 5 K.展开更多
A novel polyoxometalate {[Ag^I（4,4＇-bipy）]3[PW12O40]}·（4,4＇-bipy）·4H2O 1 has been synthesized hydrothermally and characterized by elemental analysis, IR and single-crystal X-ray diffraction. The crysta...A novel polyoxometalate {[Ag^I（4,4＇-bipy）]3[PW12O40]}·（4,4＇-bipy）·4H2O 1 has been synthesized hydrothermally and characterized by elemental analysis, IR and single-crystal X-ray diffraction. The crystal of 1 belongs to the triclinic system, space group P1 with a = 11.3710（17）, b = 12.0701（16）, c = 13.1061（12） A, α = 112.838（3）, β = 94.545（6）, γ = 99.526（4）°, V = 1614.4（4） A^3, Mr = 3825.40, Z = 1, Dc = 3.935, μ = 22.289mm^-1, F（000） = 1692, the final R = 0.0507 and wR = 0.1054. X-ray diffraction analysis reveals that the molecular structure of 1 consists of three coordinated cations [AgI（4,4＇-bipy）]＋, a polyanion unit [PW12O40]3-, and a discrete 4,4′-bipy molecule. Significantly, there exist two crystallographically independent silver（I） centers in 1 and all [AgI（4,4＇-bipy）]^＋ cations are linked with each other to form a one-dimensional Ag-4,4＇-bipy polymer chain. The neighboring polymer chains are further interconnected to form a 3D framework by the covalent effect of silver atoms and terminal oxygen atoms of the polyanion. The electrochemical behaviors of 1 have also been studied in detail by cyclic voltammograms.展开更多
A Keggin-type tungstohosphate compound [Cu^l（2,2＇-bipy）2]3[PW^Ⅵ12O40] 1 （bipy = bipyddine） was prepared by the hydrothermal method for the first time. Single-crystal X-ray diffraction revealed that 1 （C60H48Cu3...A Keggin-type tungstohosphate compound [Cu^l（2,2＇-bipy）2]3[PW^Ⅵ12O40] 1 （bipy = bipyddine） was prepared by the hydrothermal method for the first time. Single-crystal X-ray diffraction revealed that 1 （C60H48Cu3N12O40PW12） crystallizes in the monoclinic system, space group P21/c with a = 16.9837（10）, b = 17.9732（13） c = 27.8701（13）A°, β = 96.1039（10）°, V = 8459.2（9） A°^3, Mr = 4004.89, Z = 4, Dc = 3.145 g/cm^3, μ = 17.089 mm^-1, F（000） = 7208, S = 1.005, the final R = 0.0469 and wR = 0.0827 for 10807 observed reflections （I 〉 2σ（I））. Compound 1 consists of one discrete normal Keggin polyanion [PW^Ⅵ 12O40]^3- and three isolated coordinated cations [Cu^1（2,2＇-bipy）2]^＋. Significantly, there exist three crystallographically independent asymmetric reduced copper （I） centers in 1. Furthermore, the compound shows strong photoluminescence property in solid state at room temperature.展开更多
By means of pre-compressive creep treatment, the cubic γ′ phase in a nickel base single crystal superalloy is transformed into the P-type rafted structure. And the influence of the pre-compressive creep on the inter...By means of pre-compressive creep treatment, the cubic γ′ phase in a nickel base single crystal superalloy is transformed into the P-type rafted structure. And the influence of the pre-compressive creep on the internal friction stress and creep lifetimes of the superalloy are investigated by means of the measurement of the creep curves and microstructure observation. Results show that, compared to the P-type structure alloy, the full heat treated state alloy displays a bigger internal friction stress value of dislocation motion during steady state creep and a longer creep lifetimes. The creep activation energies of the full heat treated and P-type structures alloys are measured to be 462 kJ/mol and 412 kJ/mol, respectively. Thereinto, the P-type rafted γ′ phase in the alloy is transformed into the N-type structure during tensile creep. And the N-type γ′ phase transformed from the P-type structure displays a shorter size in length, this is a main reason of the P-type structure alloy possessing a shorter creep lifetimes due to creep dislocation moving easily over the rafted γ′ phase.展开更多
In this paper, we have reported an investigation on the evolution of nitrogen structures in diamond crystals which contain nitrogen donor atoms in the range of 1500 ppm-1600 ppm following an annealing treatment at a h...In this paper, we have reported an investigation on the evolution of nitrogen structures in diamond crystals which contain nitrogen donor atoms in the range of 1500 ppm-1600 ppm following an annealing treatment at a high pressure of about 6.5 GPa and high temperatures of 1920 K-2120 K. The annealing treatment was found to completely transform nitrogen atoms originally arranged in a single substitutional form （C-center）, into a pair form （A-center）, indicated from infrared （IR） spectra. The photoluminescence （PL） spectra revealed that a small fraction of nitrogen atoms remained in C-center form, while some nitrogen atoms in A-center form were further transformed into N3 and H3 center structures. In addition, PL spectra have revealed the existence of two newly observed nitrogen-related structures with zero phonon lines at 611 nm and 711 nm. All these findings above are very helpful in understanding the formation mechanism of natural diamond stones of the Ia-type, which contains nitrogen atoms in an aggregated form.展开更多
In this work, with the analysis on MO and electronic structure for a series of heteronuclear cluster with cubane type (Mo4S1 )xMn1(x=1.2. M = Cu, W, Ni, Sb, Mo, Sn, Cu2) we found that it is with the multiple center d-...In this work, with the analysis on MO and electronic structure for a series of heteronuclear cluster with cubane type (Mo4S1 )xMn1(x=1.2. M = Cu, W, Ni, Sb, Mo, Sn, Cu2) we found that it is with the multiple center d-pir orbitals that the ligand Mo3S44+ bonds to the M atom to form these class clusters. It is revealed that the charges transfer from the M atom to Mo atom of the ligand Mo3S44+ and its relationship with the MC (multiple center) d-pπ orbitals. Based on the charge transfer the electronic spectrum and the magnetic property of some cubane clusters have been discussed.展开更多
A novel Ni-capped complex H4{[Ni（H2O）3]2[CeMo12O42] }· 13.5H2O has been synthesized, which is the first Silverton-type anion capped with two Ni units via three terminal oxygen atoms. Crystallographic data for t...A novel Ni-capped complex H4{[Ni（H2O）3]2[CeMo12O42] }· 13.5H2O has been synthesized, which is the first Silverton-type anion capped with two Ni units via three terminal oxygen atoms. Crystallographic data for the title compound： Trigonal, space group R-3, a = 13.0950（19）, b = 13.0950（19）, c = 33.029（7） A, α = β= γ = 58.727（17）A °, V = 4905.1（14） A °^3, Z = 3, Mr= 2437.17, Dc = 2.475 g/cm^3, F（000） = 3462, T = 293（2） K, μ（MoKa） = 3.564 mm^-1, Rt = 0.0369, wR2 = 0.0905 and GOF= 1.079 for 151 parameters and 1963 reflections with I 〉 2σ（I） in the range of 1.85≤θ≤25.50°.展开更多
A transition metal substituted polyoxotungstate, [Cu（en）2（H2O）]2{PW11.5Cu0.5O40[Cu（en）2] }·2H2O1 based on Keggin frameworks, has bccn hydrothcrmally synthesized and characterized by IR, TGA and single-cryst...A transition metal substituted polyoxotungstate, [Cu（en）2（H2O）]2{PW11.5Cu0.5O40[Cu（en）2] }·2H2O1 based on Keggin frameworks, has bccn hydrothcrmally synthesized and characterized by IR, TGA and single-crystal X-ray structural analysis. It is interesting to find that the structure unit contains two different valence cations, narncly, one [Cu（1）（en）2（H2O）]^＋ and one [Cu（2）（en）2（H2O）]^2＋. Data for the crystal： orthorhombic system, space group Pbca, a = 21.585（2）, b = 20.695（2）, c = 26.137（3）A, V = 11675（2）A^3, Z = 8, Mr = 3428.23, Dc = 3.901 g/cm^3, F（000） = 12156,μ（MoKα） = 23.932 mm^-1, the final R = 0.0468 and wR = 0.0969 for 6927 observed reflections （I 〉 2σ（I））.展开更多
基金Financilly Supported by the National Natural Science Foundation of China
文摘By pattern recognition chemical bond parameter method, the formability of NaZn<sub>13</sub> type and BaCd<sub>11</sub> type ternary compounds in RE-M Si （RE=La-Lu, M is any metallic element） systems has been investigated. And the existence of unknown ternary compounds is predicted by the pattern recognition method.
基金supported by the Natural Science Foundation of Tianjin City (No.19JCYBJC17000)the National Natural Science Foundation of China (No.11905159)。
文摘A D-type photonic crystal fiber(PCF) sensor based on surface plasmon resonance(SPR) principle is designed.In order to excite the SPR effect,a gold film is plated on the open-loop channel of the sensor,the free electrons in a metal are resonated with photons.The structural parameters are fine-tuned and the sensing performance of the sensor is studied.The results show that the maximum spectral sensitivity reaches 18 000 nm/RIU in the refractive index range of 1.24—1.32,and the maximum resolution is 5.56×10^(-6) RIU.The novel structure with high sensitivity and low refractive index provides a new perspective for fluid density detection.
文摘We have used chemical bond parameters and pattern recognition method to investigatethe regularities of the crystal type of alloy phase,and achieved good results.Theparameters used,however,are semi-empirical paramters,which are not very strict fromtheoretical viewpoint.In this letter,we use the numbers describing atomic structure(thenumbers of valence electrons Z<sub>1</sub>,Z<sub>2</sub>,the principal quantum numbers of valence electrons n<sub>1</sub>,
基金supported by the National Natural Science Foundation of China(No.51303177)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB12020300)
文摘In this work, the mesophase properties were tuned via mixing two discotic molecules with structural complementarity. Compared with the liquid crystalline hexakis（n-hexyloxy）triphenylene（H6TP）materials（columnar hexagonal phase from 53 ℃ to 91 ℃）, mesophase types as well as phase transition temperatures varied with the introduction of crystalline hexaazatriphenylene derivative（PBH）molecules. The introduction of less than 33% amount of PBH disrupted the columnar hexagonal phase formed by H6 TP remarkably, followed by the decreased clearing temperatures of liquid crystals. As the PBH amount was further increased, the destroyed columnar hexagonal phase was turned into the columnar rectangular phase, in which H6 TP and PBH molecules together formed the columnar mesophase. The formation of new mesophase contributed to the enlarged mesophase temperature（from44 ℃ to 144 ℃）. We speculated that the alkyl chains interaction induced by the PBH component competed with the strong p–p stacking between H6 TP molecules, thus altering the liquid crystalline properties including mesophase types and phase transition temperatures.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10675114 and 10835006)the Important Direction Project of the Chinese Academy of Sciences
文摘The positron lifetimes of some compounds with NaCl-type crystal structure are calculated with the method of atomic superposition approximation （ATSUP） based on the theories of local-density-approximation （LDA） and general- gradient-approximation （GGA）. The systematical results are fitted to a curve as a function of lattice constants. The positron bulk lifetimes of some other compounds with NaCl-type crystal structure, which are deduced from the systematical results, are in agreement with the experimental results given in other literature.
基金supported by the National Natural Science Foundation of China(21001040)
文摘The compound [Cd（L）2（NO3）]NO3·0.5H2O （L = N-benzyl-2-（quinolin-8-yloxy）aceta- mide） 1 has been synthesized and structurally determined by single-crystal X-ray diffraction, elemental analysis, IR and UV spectroscopy. The crystal belongs to the triclinic system, space group P1 with a = 11.7175（13）, b = 11.8873（13）, c = 14.0958（16） A, α = 74.889（2）, β= 78.228（2）, γ = 78.831（2）°, V= 1835.0（4） A3, Z= 1, Dc= 1.502 Mg/m3, Mr = 1660.17,μ = 0.662 mm-1, F（000） = 846, 2（MoKa） = 0.71073 A, the final R = 0.0585 and wR = 0.0577 for all observed reflections. The results show that the Cd（II） ion with a square antiprismatic geometry is coordinated by a N206 donor set, two NO2 sets from two ligands and two O atoms from a bidendate nitrate group. In the crystal, the O-H...O and N-H...O hydrogen bonds are helpful to consolidate the three- dimensional network.
基金Project supported by the National Natural Science Foundation of China(Nos.11272126,51435006,and 51121002)the Fundamental Research Funds for the Central Universities(Nos.HUST:2016JCTD114 and HUST:2015TS121)
文摘A folding beam-type piezoelectric phononic crystal model is proposed to isolate vibration. Two piezoelectric bimorphs are joined by two masses as a folding structure to comprise each unit cell of the piezoelectric phononic crystal. Each bimorph is connected independently by a resistive-inductive resonant shunting circuit. The folding structure extends the propagation path of elastic waves, while its structure size remains quite small. Propagation of coupled extension-flexural elastic waves is studied by the classical laminated beam theory and transfer matrix method. The theoretical model is further verified with the finite element method(FEM). The effects of geometrical and circuit parameters on the band gaps are analyzed. With only 4 unit cells, the folding beam-type piezoelectric phononic crystal generates two Bragg band gaps of 369 Hz to1 687 Hz and 2 127 Hz to 4 000 Hz. In addition, between these two Bragg band gaps, a locally resonant band gap is induced by resonant shunting circuits. Appropriate circuit parameters are used to join these two Bragg band gaps by the locally resonant band gap.Thus, a low-frequency and broad band gap of 369 Hz to 4 000 Hz is obtained.
基金This work was supported by the National Natural Science Foundation of China (No. 29674025) and the Natural Science Foundation of Henan Province.
文摘A new series of chiral shish-kebab type liquid crystal block copolymers that form the smectic C(Sc*) phase was synthesized by solution polycondensation. The copolymers were characterized by GPC, DSC, TG, POM, X-ray diffraction and polarimeter. The copolymers 7 entered into liquid crystal phase whin they were heated to their melting temperatures (T-m) and the copolymers 8 were in liquid crystal phase at room temperature with low viscosities. The smectic sanded texture or focal-conic texture were observed on POM. All the chiral block copolymers showed high optical activity. No racemization has happened. Temperature-variable X-ray diffraction study together with POM and polarimetric analysis realized that they are chiral smectic C(Sc*) phase. Thus we offer in this report the first example of shish-kebab type liquid crystal block copolymers that form a chiral smectic C(Sc*) phase. The variation of melting and isotropization temperatures with molecular structure was also discussed.
文摘Reaction crystallization of struvite in water solutions containing 0.20 mass % of phosphate(V) ions by magnesium and ammonium ions addition was investigated experimentally. Process was carried out in DTM type crystallizer with liquid jet pump device in 298 K assuming stoichiometric conditions. Struvite crystals of mean size Lm 5.2-23.0 μm were produced depending on pH (9-11) and mean residence time of suspension in a crystallizer τ (900-3600 s). Under these conditions linear growth rate of struvite crystals (SIG MSMPR kinetic model) decreased 2-time with the increase in pH and 3-time with the elongation of mean residence time of crystal suspension from 7.11×10-9 m/s (pH 9, τ900 s) to 1.65×10-9 m/s (pH 11, τ3600 s). Nucleation rate varied within the 7.9×108-1.8×1010 1/(sm3) limits. Struvite product of maximal linear size exceeded 100 μm with 10 vol. % of < 3 μm fraction corresponded to pH 9 and τ3600 s.
基金financial support of National Nature Science Foundation (21376178)TIDA giant growth plan (2011-XJR13020)+3 种基金Tianjin Science and technology support program (12ZCDZSF06900)Tianjin University of Science and Technology fund for scientific research (20120119)Tianjin education commission program (20130509)Research fund for the doctoral program of higher education of China(20131208120001)
文摘1 Introduction Calcium sulfate deposition is one of the most important and serious problems faced by heat transfer equipment during operation(Pavlos et al.,1999;Liu et al.,1996).The crystallization of calcium sulfate is known as a major
基金financial support of National Nature Science Foundation (21376178)TIDA giant growth plan (2011-XJR13020)+3 种基金Tianjin Science and technology support program (12ZCDZSF06900)Tianjin University of Science and Technology fund for scientific research (20120119)Tianjin education commission program (20130509)Research fund for the doctoral program of higher education of China (20131208120001)
文摘1 Introduction There exist calcium and sulfate ions outside sodium chloride in solution mining for calcium sulfate brine.The calcium and sulfate ions not only affect the purity of the vacuum salt products,but also increase the scaling of vacuum evaporation tanks and brine reusing pipes.Additives have certain impacts on the crystallization dynamics(Randolph et al.,1971).The crystallization
基金financially supported by the National High Technology Research and Development Program of China(No.2011AA03A402)the International Scientific and Technological Cooperation Projects(No.2010DFB53520)
文摘The crystal structure and magnetic properties of SmFeg_xCox （x = 0, 1, 3, 5） alloys were studied by X-ray powder diffraction （XRD） and magnetic measurements. The Th2Znl7-type structure of the as-cast state is changed to TbCu7-type structure after quenching to a rotating molybdenum roll under certain velocity （12, 20, and 32 m.s-l）. The （002） XRD peak appears and ^-Fe phase disappears when the Co is added up to x = 5. Saturation magnetization of SmFe9 under different temperature shows 9 % change （112-102 A.m2.g-1） when the temperature is higher than 200 K. The saturation magnetization is 115 A.m2.g-1 and coercivity is 0.304 T at 5 K for SmFe9 alloys. Increased saturation magnetization and decreased coercivity can be obtained for Co added up to x = 5 at 5 K.
基金Supported by the Ministry of Education of China (No. 208066)the Education Department of Fujian Province (JA07029)+1 种基金the Natural Science Foundation of Fujian Province (2010J01026)the State Key Laboratory of Structural Chemistry (No. 20080053)
文摘A novel polyoxometalate {[Ag^I（4,4＇-bipy）]3[PW12O40]}·（4,4＇-bipy）·4H2O 1 has been synthesized hydrothermally and characterized by elemental analysis, IR and single-crystal X-ray diffraction. The crystal of 1 belongs to the triclinic system, space group P1 with a = 11.3710（17）, b = 12.0701（16）, c = 13.1061（12） A, α = 112.838（3）, β = 94.545（6）, γ = 99.526（4）°, V = 1614.4（4） A^3, Mr = 3825.40, Z = 1, Dc = 3.935, μ = 22.289mm^-1, F（000） = 1692, the final R = 0.0507 and wR = 0.1054. X-ray diffraction analysis reveals that the molecular structure of 1 consists of three coordinated cations [AgI（4,4＇-bipy）]＋, a polyanion unit [PW12O40]3-, and a discrete 4,4′-bipy molecule. Significantly, there exist two crystallographically independent silver（I） centers in 1 and all [AgI（4,4＇-bipy）]^＋ cations are linked with each other to form a one-dimensional Ag-4,4＇-bipy polymer chain. The neighboring polymer chains are further interconnected to form a 3D framework by the covalent effect of silver atoms and terminal oxygen atoms of the polyanion. The electrochemical behaviors of 1 have also been studied in detail by cyclic voltammograms.
基金Project supported by the Natural Science Foundation of Fujian Province (E0310016) and the Education Committee Foundation of Fujian Province (JB05309)
文摘A Keggin-type tungstohosphate compound [Cu^l（2,2＇-bipy）2]3[PW^Ⅵ12O40] 1 （bipy = bipyddine） was prepared by the hydrothermal method for the first time. Single-crystal X-ray diffraction revealed that 1 （C60H48Cu3N12O40PW12） crystallizes in the monoclinic system, space group P21/c with a = 16.9837（10）, b = 17.9732（13） c = 27.8701（13）A°, β = 96.1039（10）°, V = 8459.2（9） A°^3, Mr = 4004.89, Z = 4, Dc = 3.145 g/cm^3, μ = 17.089 mm^-1, F（000） = 7208, S = 1.005, the final R = 0.0469 and wR = 0.0827 for 10807 observed reflections （I 〉 2σ（I））. Compound 1 consists of one discrete normal Keggin polyanion [PW^Ⅵ 12O40]^3- and three isolated coordinated cations [Cu^1（2,2＇-bipy）2]^＋. Significantly, there exist three crystallographically independent asymmetric reduced copper （I） centers in 1. Furthermore, the compound shows strong photoluminescence property in solid state at room temperature.
基金Supported by the National Natural Science Foundation of China (No 50571070)
文摘By means of pre-compressive creep treatment, the cubic γ′ phase in a nickel base single crystal superalloy is transformed into the P-type rafted structure. And the influence of the pre-compressive creep on the internal friction stress and creep lifetimes of the superalloy are investigated by means of the measurement of the creep curves and microstructure observation. Results show that, compared to the P-type structure alloy, the full heat treated state alloy displays a bigger internal friction stress value of dislocation motion during steady state creep and a longer creep lifetimes. The creep activation energies of the full heat treated and P-type structures alloys are measured to be 462 kJ/mol and 412 kJ/mol, respectively. Thereinto, the P-type rafted γ′ phase in the alloy is transformed into the N-type structure during tensile creep. And the N-type γ′ phase transformed from the P-type structure displays a shorter size in length, this is a main reason of the P-type structure alloy possessing a shorter creep lifetimes due to creep dislocation moving easily over the rafted γ′ phase.
基金Project supported by the Natural Science Foundation of Heilongjiang Province,China(Grant No.E201341)the Open Research Program of Key Lab of Superhard Materials of Mudanjiang Normal College,China(Grant No.201302)
文摘In this paper, we have reported an investigation on the evolution of nitrogen structures in diamond crystals which contain nitrogen donor atoms in the range of 1500 ppm-1600 ppm following an annealing treatment at a high pressure of about 6.5 GPa and high temperatures of 1920 K-2120 K. The annealing treatment was found to completely transform nitrogen atoms originally arranged in a single substitutional form （C-center）, into a pair form （A-center）, indicated from infrared （IR） spectra. The photoluminescence （PL） spectra revealed that a small fraction of nitrogen atoms remained in C-center form, while some nitrogen atoms in A-center form were further transformed into N3 and H3 center structures. In addition, PL spectra have revealed the existence of two newly observed nitrogen-related structures with zero phonon lines at 611 nm and 711 nm. All these findings above are very helpful in understanding the formation mechanism of natural diamond stones of the Ia-type, which contains nitrogen atoms in an aggregated form.
文摘In this work, with the analysis on MO and electronic structure for a series of heteronuclear cluster with cubane type (Mo4S1 )xMn1(x=1.2. M = Cu, W, Ni, Sb, Mo, Sn, Cu2) we found that it is with the multiple center d-pir orbitals that the ligand Mo3S44+ bonds to the M atom to form these class clusters. It is revealed that the charges transfer from the M atom to Mo atom of the ligand Mo3S44+ and its relationship with the MC (multiple center) d-pπ orbitals. Based on the charge transfer the electronic spectrum and the magnetic property of some cubane clusters have been discussed.
基金The project was supported by the National Doctoral Research Foundation of China, Henan Innovation Project for University Prominent Research Talents, the Institute of Education of Henan Province and Natural Science Foundation of Henan Province
文摘A novel Ni-capped complex H4{[Ni（H2O）3]2[CeMo12O42] }· 13.5H2O has been synthesized, which is the first Silverton-type anion capped with two Ni units via three terminal oxygen atoms. Crystallographic data for the title compound： Trigonal, space group R-3, a = 13.0950（19）, b = 13.0950（19）, c = 33.029（7） A, α = β= γ = 58.727（17）A °, V = 4905.1（14） A °^3, Z = 3, Mr= 2437.17, Dc = 2.475 g/cm^3, F（000） = 3462, T = 293（2） K, μ（MoKa） = 3.564 mm^-1, Rt = 0.0369, wR2 = 0.0905 and GOF= 1.079 for 151 parameters and 1963 reflections with I 〉 2σ（I） in the range of 1.85≤θ≤25.50°.
基金the Program for New Century Excellent Talent in University of Henan ProvinceNatural Science Foundation of Henan Province
文摘A transition metal substituted polyoxotungstate, [Cu（en）2（H2O）]2{PW11.5Cu0.5O40[Cu（en）2] }·2H2O1 based on Keggin frameworks, has bccn hydrothcrmally synthesized and characterized by IR, TGA and single-crystal X-ray structural analysis. It is interesting to find that the structure unit contains two different valence cations, narncly, one [Cu（1）（en）2（H2O）]^＋ and one [Cu（2）（en）2（H2O）]^2＋. Data for the crystal： orthorhombic system, space group Pbca, a = 21.585（2）, b = 20.695（2）, c = 26.137（3）A, V = 11675（2）A^3, Z = 8, Mr = 3428.23, Dc = 3.901 g/cm^3, F（000） = 12156,μ（MoKα） = 23.932 mm^-1, the final R = 0.0468 and wR = 0.0969 for 6927 observed reflections （I 〉 2σ（I））.
