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Hu Gang

Publications and source records attributed to Hu Gang.

5 recordsLinked to original sources
PubMed2006

Structural evolution of polymer-stabilized double emulsions.

Polymer-stabilized double emulsions are produced by a two-step process, high shear emulsification in the primary and membrane emulsification in the secondary. By repeated fractionation after each emulsification, we obtain monodisperse double emulsions with the size of the complex droplets ranging from submicrometer to a few micrometers. With osmotic pressure balance between the inner and outer phases, the polymer-stabilized double emulsions remain stable for a year at room temperature without structure deterioration. We generalize laser light scattering to probe the structure and internal dynamics of the complex system by including the effects of the amplitude fluctuations of the scattered fields. Both static light scattering (SLS) and dynamics light scattering (DLS) can resolve the inclusions inside the complex droplets. Water-soluble nonionic surfactants are used to induce destabilization of double emulsions. We find that a double emulsion turns into a simple emulsion within a minute at a surfactant concentration of less than 10(-)(3) mol/L. We demonstrate that DLS is a powerful technique to study the kinetics of destabilization of double emulsions. Coalescence between the internal droplets and the external continuous phase is identified as a major release pathway.

Journal Article↗
PubMed2005

Urban solid waste management in Chongqing: challenges and opportunities.

The dual influences of the resource supply and protection in ecological environments will pose a significant challenge to China's sustainable development. Solid waste management offers opportunities to improve profits by conserving resources and improving environmental performance. This paper examines municipal solid waste (MSW) management in urban Chongqing, the nation's fourth largest municipality after Beijing, Shanghai and Tianjin. In this paper, we will provide information on the quantity and composition of MSW, as well as give an overview of different methods for collection, transport, treatment and disposal of MSW. At present the daily amount of MSW generated per person is about 1.08 kg; food waste accounts for about 59% of total MSW. MSW in Chongqing has a higher moisture content (64.1%) and a lower LHV (3728 kJ/kg) than other cities in Asia, which is an obstruction for incineration. Landfills are the main method of disposal in Chongqing, but pollution caused by simple landfills and lack of backup MSW disposal capacity are becoming major problems in the main districts of Chongqing. In this paper, the challenges being faced and opportunities to MSW in Chongqing are analyzed and some suggestions are given for improving the MSW system in the future.

Cities↗
PubMed2004

Error function attack of chaos synchronization based encryption schemes.

Different chaos synchronization based encryption schemes are reviewed and compared from the practical point of view. As an efficient cryptanalysis tool for chaos encryption, a proposal based on the error function attack is presented systematically and used to evaluate system security. We define a quantitative measure (quality factor) of the effective applicability of a chaos encryption scheme, which takes into account the security, the encryption speed, and the robustness against channel noise. A comparison is made of several encryption schemes and it is found that a scheme based on one-way coupled chaotic map lattices performs outstandingly well, as judged from quality factor.

Algorithms↗
PubMed2003

Measure synchronization in coupled phi4 Hamiltonian systems.

Transitions to measure synchronization both in the quasiperiodic and chaotic cases are investigated based on numerical computation of two coupled phi(4) equations. Some relevant quantities such as the bare energies, the interaction energy, and the phase difference of the two oscillators are computed to clarify the characteristics of the transitions and the measure-synchronous states. A bifurcation with discontinuous bare energy and continuous interaction energy, which takes the maximum value at the critical point, is found for the transition from the desynchronous quasiperiodic state to the measure-synchronous quasiperiodic state, and the related power law scalings are deduced. Stick-slip and random-walk-like behavior of the phase difference is found for the chaotic measure-synchronous state, and this explains the monotonous increase of the interaction energy with an increase of coupling.

Journal Article↗