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130 results on '"Hu, Jiang-Tao"'

32. Preparation and properties of addition curable silicone resins with excellent dielectric properties and thermal resistance

Author

Zhang, Beijing, Zhuo, Dongxian, Gu, Aijuan, Liang, Guozheng, Hu, Jiang-Tao, and Yuan, Li

Subjects
Silicones -- Usage, Epoxy resins -- Chemical properties -- Composition -- Production processes -- Identification and classification -- Electric properties -- Thermal properties, Dielectrics -- Chemical properties -- Composition -- Production processes -- Identification and classification -- Thermal properties, Engineering and manufacturing industries, Science and technology
Abstract

A new addition curable silicone resin (ASiR) system with excellent dielectric and thermal properties was developed, which consists of only two components: poly (methylphenylvinylsiloxane) (PMPVSi) and an end-capped hydrogen-functionalized hyperbranched polysiloxane (EHFHPSi). PMPVSi is synthesized by a green and controllable process; EHFHPSi is first synthesized via [A.sub.2] + [B.sub.3] approach, and then end-capped by hexamethyldisiloxane (HMDS). Three formulations were designed to investigate the optimum stoichiometry. Results show that cured ASiR resins have greatly different dielectric and thermal properties because of the different chemical structure of cured networks resulting from the different stoichiometrics. The resin with a suitable stoichiometry has not only excellent dielectric properties including extremely low dielectric constant (2.96 at 1 Hz) and loss (0.0003 at 1 Hz) as well as good stability on frequency, but also outstanding thermal resistance, exhibiting great potential to be used as a new kind of high-performance resins for many cutting-edge industries, especially the microelectronic and insulation fields. POLYM. ENG, SCI., 52:259-267, 2012. © 2011 Society of Plastics Engineers, INTRODUCTION Addition curable silicone resins are known to be cross-linked semi-inorganic polymers with the Si-O-Si chains as backbones and some organic groups as side chains, which possess combined properties of [...]

Published
2012
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38. Thermal and Moisture Transport Inhibitions in a Moist Air Saturated Enclosure Attached with Protruding Partitions for Built Energy Conservations.

Author

Zhao, Fu-Yun, Li, Lin, Liu, Di, Hu, Jiang-Tao, and Wang, Han-Qing

Subjects
MOISTURE, HEAT transfer, THERMODYNAMICS, MASS transfer, RAYLEIGH number, TEMPERATURE
Abstract

Combined heat and moisture transportation in an enclosure has been numerically investigated, which could benefit the sustainable building energy conservations and electronic cooling designs. An adiabatic and impermeable partition of finite thickness is considered, placed in the enclosure following an ordered arrangement. Effects of length and location of the partition, buoyancy ratio and thermal Rayleigh number on convective heat and moisture transfer rates in the enclosure are discussed. Firstly, this situation of the partition placed in the horizontal wall is studied, where inhibition effect of partition is observed. It is seen that the location of partition put relatively weaker influences on the heat and mass transfer in the regime of thermal-driven flow, when its length exceeds the critical value. Additionally, inhibition effect is more pronounced as the partition is fixed in center of vertical wall. Furthermore, local heat and mass transfer rates could be suppressed when the buoyancy ratio becomes negative. Finally, thermal Rayleigh number greatly affects the transport structures of fluid, heat and moisture, whatever aiding flow or opposing flow situations. Heat and mass transfer potentials could be promoted with increasing thermal Rayleigh numbers. Present work could be adopted to optimize the enclosure flows simultaneously with heat and moisture transport. [ABSTRACT FROM AUTHOR]

Published
2018
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42. A density functional theory study on the interaction between UO22+and the carbamoylphosphoramidic acid ligand for uranium extraction from seawater

Author

Guo, Xiao-Jing, Li, Cheng, Hu, Jiang-Tao, Ma, Hong-Juan, and Qian, Hong-Liang

Abstract

Phosphorylurea molecules, which contain both phosphoryl and carbonyl groups, are considered efficient extractants for UO22+. This study aims to explain the complexation of UO22+with carbamoylphosphoramidic acid (CPO), a simple model for phosphorylurea, for ligand design for uranium recovery from seawater using density functional theory calculations, natural bond order analysis, and the quantum theory of atoms in molecules. The results showed that, when CPO acts as a monodentate ligand, the affinity of phosphoryl for UO22+is stronger than that of carbonyl, and CPO coordinates with UO22+through the phosphoryl oxygen atom. When CPO serves as a bidentate ligand, both the phosphoryl and carbonyl oxygen atoms connect to UO22+, and the U–O(carbonyl) bond plays a more important role than the U–O(phosphoryl) bond in the interaction between UO22+and CPO. This paradox may be caused by the significant charge transfer from the U–O(carbonyl) π bond orbital to the C–N σ antibond orbital of the bidentate CPO. The NH spacer between the phosphoryl and carbonyl groups could ensure the delocalization of the electron system of the molecule. The bidentate binding motif is favored by entropy and opposed by enthalpy, while the monodentate binding motif is favored by enthalpy and opposed by entropy. Ultimately, the bidentate binding motif is more favorable than the monodentate one. As expected, the interaction between UO22+and the deprotonated CPO is stronger than that between UO22+and the neutral CPO. Comparing the interaction between UO22+and CPO with that between UO22+and N-phenylcarbamoylphosphoramidic acid (PhCPO), formed by replacing one hydrogen atom from the terminal nitrogen atom of CPO with a phenyl group, the phenyl substituent at the terminal nitrogen atom of PhCPO shows a slightly negative effect on the interaction between UO22+and PhCPO.

Published
2018
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