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1

The impact of changes in pore structure on the compressive strength of sulphoaluminate cement concrete at high temperature

Tchekwagep J. J. K., Zhao P., Wang S., Huang S., Cheng X.

Materials Science Poland

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2021

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Vol. 39, No. 1

75--85

EN

The internal pore structure of sulphoaluminate cement concrete (SACC) significantly affects its mechanical properties. The main purpose of this study was to establish the relationship between pore structure changes and compressive strength after exposure to elevated temperatures. SACC samples that had been cured for 12 months were dried to a constant weight and then exposed to different temperatures (100 °C, 200 °C and 300 °C), after which the compressive strength and pore structure were measured. The pore structure of SACC was quantitatively described by mercury intrusion porosimetry (MIP) and nitrogen adsorption results. The results showed that with increased temperature, the porosity of the SACC samples also increased and the pore structure was gradually destroyed. Moreover, the SACC’s compressive strength gradually decreased with increasing temperature. The relationship between compressive strength and porosity was in close agreement with the compressive strength–porosity equation proposed by Schiller. Therefore, after extensive exposure to elevated temperature, the changes in SACC’s compressive strength can be quantitatively described by the Schiller equation.

2

Technical application of petroleum logging instruments in marine logging

Gu G., Zhao P., Wang L., Guo H.

Polish Maritime Research

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2018

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S 3

22--28

EN

To solve the problem of offshore oilfield development, based on the newly introduced pulsed neutron oxygen activation logging instrument, the application research of test design and interpretation method was carried out and applied to actual production. The structure, technical indicators and logging principles of pulsed neutron oxygen activation logging tools were introduced. The test design under different well conditions was studied, including general positive and negative injection, oil sleeve injection, single oil pipe configuration and multitubing configuration. A large amount of field test data was collected and analysed technically. A set of effective interpretation models was proposed. The corresponding interpretation software was developed. A set of test design methods and operating specifications for different well conditions were developed. Based on the conventional interpretation method, the peak selection, the double-tuber peak identification and the carbon dioxide flooding interpretation method were added. The results show that the test design and interpretation methods were applied well through a large number of field tests and production applications. Therefore, pulsed neutron oxygen activated injection profile logging technology is successfully applied in offshore oil fields.

3

A 2-bit polymer waveguide delay device using right-angle X junctions

Yi Y, Wang Q., Zhao P., Wang F., Zhang D.

Optica Applicata

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2012

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Vol. 42, nr 1

111--120

EN

A 2-bit polymer waveguide delay device composed of right-angle junctions, Mach-Zehnder thermo-optic switches and bending polymer waveguides is demonstrated. The four path device and Mach-Zehnder thermo-optic switch are fabricated using direct ultraviolet photolithography process. The fabrication procedures are demonstrated. The loss of bending waveguides, right-angle X junctions and Mach-Zehnder thermo-optic switches is calculated and analyzed. The near-infrared field guided-mode patterns of the device are obtained. Time delays of the 2-bit device are measured to be 0, 121.1, 242.3, and 365.7 ps.

4

Performance of soil particle-size distribution models for describing deposited soils adjacent to constructed dams in the China Loess Plateau

Zhao P., Shao M., Horton R.

Acta Geophysica

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2011

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Vol. 59, no. 1

124-138

EN

Soil particle-size distributions (PSD) have been used to estimate soil hydraulic properties. Various parametric PSD models have been proposed to describe the soil PSD from sparse experimental data. It is important to determine which PSD model best represents specific soils. Fourteen PSD models were examined in order to determine the best model for representing the deposited soils adjacent to dams in the China Loess Plateau; these were: Skaggs (S-1, S-2, and S-3), fractal (FR), Jaky (J), Lima and Silva (LS), Morgan (M), Gompertz (G), logarithm (L), exponential (E), log-exponential (LE), Weibull (W), van Genuchten type (VG) as well as Fredlund (F) models. Four-hundred and eighty samples were obtained from soils deposited in the Liudaogou catchment. The coefficient of determination (R2), the Akaike’s information criterion (AIC), and the modified AIC (mAIC) were used. Based upon R2 and AIC, the three- and four-parameter models were both good at describing the PSDs of deposited soils, and the LE, FR, and E models were the poorest. However, the mAIC in conjunction with R2 and AIC results indicated that the W model was optimum for describing PSD of the deposited soils for emphasizing the effect of parameter number. This analysis was also helpful for finding out which model is the best one. Our results are applicable to the China Loess Plateau.

5

Practical stability in terms of two measures for hybrid dynamic systems

Sun S., Han Z., Akin-Bohner E., Zhao P.

Bulletin of the Polish Academy of Sciences. Mathematics

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2010

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Vol. 58, no 3

221-237

EN

We study hybrid dynamic systems on time scales. Using Lyapunov-like functions, we obtain sufficient conditions for practical stability and strict practical stability in terms of two measures for hybrid dynamic systems on time scales.

6

Quantum Chemistry Studies on Bis(p-aminobenzoato)–lead(II) Complex [Pb(C6H4NH2COO)2]

Zhao P., Xu J., Li R., Zhang W., Cai Z.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 1

85-93

EN

The title complex, bis(p-aminobenzoato)–lead(II) [Pb(C6H4NH2COO)2], has been optimized at B3LYP/LANL2DZ level of theory and the calculated results show that the lead(II) ion adopts a four-coordinate geometry. The analyses of NPA and Mulliken atomic charge distributions indicate that during the process of the formation of this compound, both aminobenzoato ligands transfer their negative charges to the lead(II) ion. The lead atom and oxygen atoms form covalent bonds by using their 6p and 2p orbitals, respectively. The calculations of electronic spectra of the title complex show that there exist four absorption bands and the electronic transitions are mainly derived from the contributions ofboth an intraligand* transition and ligand-to-metal charge transfer (LMCT) transitions. The thermodynamic properties of the studied compound at different temperatures have been calculated and the corresponding relations between the properties and temperatures have also been obtained. The calculation of the second order optical nonlinearity has been carried out, and the molecular hyperpolarizability of the title complex is 7.61379x10–30 esu.

7

Experimental and Theoretical Study on 3-Benzyl-4-phenyl-1,2,4-triazole-5-thione

Zhao P., Li R., Xu J., Zhang W.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 8

1495-1503

EN

The 3-benzyl-4-phenyl-1,2,4-triazole-5-thione was synthesized and examined by elementary analysis, IR and electronic spectra. Density functional theory calculations of the structure, natural bond orbitals and thermodynamic functions of the title compound were performed at B3LYP/6-311G** level of theory. Vibrational frequencies were predicted, assigned and compared with the experimental data, and they are supported by the experimental data. Electronic absorption spectrawere calculated by the time-dependent density functional theory (TD-DFT), which indicates that the two absorption bands are mainly derived from the contribution of bands *. The calculation of the second order optical nonlinearity was carried out, giving value of molecular hyperpolarizability equal to 4.025ź10–30 esu. These calculated results were also compared with results obtained for a similar molecule, 4-phenyl-3-[(1,2,4-triazol-1-yl)methyl]-triazole-5-thione, reported earlier by this group.

8

Experimental and Density Functional Studies on Two Substituted 1H-Benzimidazoles

Zhao P., Yu H., Jian F., Wang X.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 8

1511-1519

EN

Two substituted 1H-benzimidazoles, 2-(4-chlorophenyl)-1H-benzimidazole and 1-(2- chlorobenzyl)-2-(2-chlorophenyl)-1H-benzimidazole, have been synthesized and characterized by elemental analysis, IR and UV-Vis spectra. An extended MO calculations using density functional theory (DFT) at B3LYP/6-311G** level have been carried out on the two compounds. Comparison of the experiments with the calculated results suggests that the optimized geometries can well reproduce the molecular structures. Atomic charge distributions show that both of the title compounds are potential ligands to coordinate with metallic ions. Natural population analyses indicate that the electronic transitions corresponding to electronic spectra are mainly derived from the contribution of bands pi--pi*. Thermodynamic properties of the two title compounds at different temperatures have also been calculated on the basis of vibration analyses.

9

Experimental and Theoretical Study on4-Phenyl-3-[(1,2,4-triazol-1-yl)methyl]-triazole-5-thione

Jian F., Zhao P., Bai Z., Cai Z.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 2

325-333

EN

The title compound, 4-phenyl-3-[(1,2,4-triazol-1-yl)methyl]-triazole-5-thione, was synthesized and characterized by elemental analysis, IR and electronic spectra. Density functional theory calculations of the structure, natural bond orbital and thermodynamic functions of the title compound were performed at B3LYP/6-311G** level of theory. Vibrational frequencies were predicted, assigned, compared with the experimental values, and they are supported each other. Electronic absorption spectra were calculated by the time-dependent density functional theory (TD-DFT), which indicates that the two absorption bands aremainly derived from the contribution of bands pi--pi*. The calculation of the second order optical nonlinearity was carried out with PM3 semi-empirical method that resulted in the molecular hyperpolarizability equal to 4.397x10-30 esu.

10

Density Functional Calculations on a Double Hydrogen Bonded Dimer of (p-Methoxyphenyl)thiosemicarbazide

Zhao P., Li R., Zhang L., Jian F.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 12

2031-2039

EN

Density functional theory (DFT) calculations on a double hydrogen-bonded dimer of (p-methoxyphenyl)thiosemicarbazide were carried out at B3LYP/6-31G* level. The optimized geometry of the dimer closely resembles that in the crystal. The calculated results show that the total energy of the dimer is much lower than the sum of energies of the two monomers, and the average strength of the double hydrogen bond is about 21.92 kJ/mol. In order to probe the origin of the interactions in the dimer, natural bond orbital analyses have been performed. The thermodynamic properties of the title compound at different temperatures have also been calculated on the basis of vibrational analyses and the change of Gibbs free energy for dimerization of the twomonomers.GT = –18.40 kJ/mol at 298.15 K and 0.1MPa, which implies the spontaneous process of the dimer formation. The correlation graphs of Sm 0, Hm 0 and temperatures for the dimer are depicted.

11

Experimental Studies on Isonicotinato Zinc(II) Complex [Zn(C6H4NO2)2(H2O)4] and Density Functional Calculations

Zhao P., Jian F., Li C.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 6

1041-1046

EN

Isonicotinato zinc(II) complex [Zn(C6H4NO2)2(H2O)4] has been synthesized by hydrothermal method and characterized by elemental analysis, electronic-spectra and thermogravimetric analysis. Density functional theory (DFT) method calculations of the structure, atomic charges distribution, electronic spectra, natural population analysis and the thermodynamic properties at different temperatures have been performed. The calculated results show the electronic transitions are mainly derived from the contribution of pi--pi* bands and the decomposition of the title compound should firstly occur at the bond of Zn-O, then at the bond of Zn-N, which agrees very well with the experimental data.

12

Crystal Structure, Infrared Spectra and Density Functional Theory Study on 2,3-Diketo-benzopiperazine Dimer

Zhao P., Jian F. F., Xiao H., Sun P.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 10

1935-1944

EN

2,3-Diketo-benzopiperazine, which exists as dimeric form in its crystal structure has been synthesized. The calculated results on the dimer at B3LYP/6-31G* level show that the average strength of the double hydrogen bonds is of medium-grade. Natural bond orbital analyses have been performed. The predicted harmonic vibration frequencies support the experimental values. The thermodynamic properties of the dimer at different temperatures have been calculated and the change of Gibbs free energy for the aggregation from the monomer to the dimerDelta GT = -30.86 kJ/mol at 298.15 K, which implies the spontaneous process of the dimer formation.

13

Crystal Structure and Ab Initio Studies on (p-Methoxyphenyl)thiosemicarbazide

Zhao P., Jian F., Hou Y.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 10

1945-1951

EN

(p-Methoxyphenyl)thiosemicarbazide [CH3OC6H4NHNHCSNH2] has been prepared and characterized by elemental analysis, IR, electronic absorption spectra and X-ray single crystal diffraction. In the crystal lattice, there exist some intermolecular hydrogen bonds, _-_ stacking interactions and C-Hźźź_ supramolecule interactions, which stabilize the crystal structure. Ab initio calculations at HF/6-31G* level of the structure, charges distribution, electronic spectra, natural population analysis and thermodynamic properties at different temperatures have been performed. The calculated results show that the sulfur atom and nitrogen atoms have bigger negative charges, which result in they are the potential sites to react with the metallic ions. The electronic transitions associated with the electronic absorption spectra are mainly derived from the contribution of bands pi-pi*.