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Kinetics and mechanism of one-step reductive leaching of manganese oxide ores by EDTA/EDTA-2Na

Zhang C., Wang S., Cao Z., Zhong H.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 3

858--867

EN

In this research, the kinetics and mechanism of one-step reductive leaching of manganese oxide ores by ethylenediaminetetraacetic acid (EDTA) or its disodium salt (EDTA-2Na) in an aqueous medium have been investigated. The kinetic data of this reductive leaching process may be described by the Avrami model, and the apparent activation energy was determined to be 15.8 kJ·mol-1/7.9 kJ·mol-1 for leaching by EDTA/EDTA-2Na with a reaction order of -1.7/2.0. The EDTA/EDTA-2Na leach liquor characterized and analyzed by X-ray photoelectron spectra (XPS), Fourier transform infrared spectra (FTIR), and total organic carbon (TOC) determination denoted that the oxidation-reduction reaction happened between manganese(IV) and EDTA/EDTA-2Na, and a coordination complex, EDTA-manganese(II/III) formed. This new process can be easily used to leach manganese from manganese oxide ores in a moderate environment with the pH range of 5–8.

2

Proof of Multicopy via Proof of File Position in Cloud

Zhang H., Cao Z., Dong X., Shen J.

Fundamenta Informaticae

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2018

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Vol. 157, nr 1/2

141--151

EN

For disaster recovery, we store backups of a file in several positions far away from each other. If we delegate this task to an untrusted cloud service provider, a verification method is desired. In this paper, we construct a generic transformation from “proof of retrievability” to “proof of multicopy”. We present this work in two stages. In the first stage, we propose a generic protocol of “proof of file position” based on an arbitrary secure “proof of retrievability” protocol. In the second stage, we propose a “proof of multicopy” protocol based on our “proof of file position” protocol. Both of our protocols are provably secure.

3

Adaptive robust simultaneous stabilization controller with tuning parameters design for two dissipative Hamiltonian systems

Cao Z., Hou X., Zhao W.

Archives of Control Sciences

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2017

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Vol. 27, no. 4

505--525

EN

This paper investigates the problem of adaptive robust simultaneous stabilization (ARSS) of two dissipative Hamiltonian systems (DHSs), and proposes a number of results on the controller parameterization design. Firstly, an adaptive H∞ control design approach is presented by using the dissipative Hamiltonian structural for the case that there are both external disturbances and parametric uncertainties in two DHSs. Secondly, an algorithm for solving tuning parameters of the controller is proposed using symbolic computation. The proposed controller parameterization method avoids solving Hamilton-Jacobi-Issacs (HJI) equations and the obtained controller is easier as compared to some existing ones. Finally, an illustrative example is presented to show that the ARSS controller obtained in this paper works very well.

4

Effects of Pinus massonian plantations on soil macroarthropods in degraded ultisol, Subtropical China

Ding C., Hu F., Zhou J., Cao Z., Li H., Dai Z.

Archives of Environmental Protection

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2008

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Vol. 34, no. 3

17-20

EN

In the degraded red soil of subtropical China, restoration activities during the last century have mainly relied on extensive plantations of Pinus massonian. We analyze the changes in the soil macroarthropods in P. massonian plantations and the possible relationships between these changes and soil chemical parameters. The study revealed significant differences in the abundance of soil macroarthropods between the P. massonian plantations and the natural regenerated mesophilous herbosa (Nl). The sharply differentiated pattern of soil macroarthropods seems closely linked to soil chemistry. Significant correlations of the abundance of soil macroarthropods with soil parameters suggest that their populations could have been affected by P massonian. The total abundance, the abundance of Hymenoptera and Termite were less in the P. massonian plantations when compared to the natural regenerated mesophilous herbosa (Nl). This survey showed that P.massonian could adversely affect the decomposer community which could lower the nutrient cycling rate, thus P.massonian may not be an ideal plantation for restoration of eroded Ultisol, Subtropical China.

5

A New Practical Limited Identity-Based Encryption Scheme

Lu R., Cao Z., Dong X.

Fundamenta Informaticae

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2007

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Vol. 80, nr 4

461-474

EN

Identity based cryptography was introduced by Shamir in 1984, which avoids the trust problems encountered in the traditional Public Key Infrastructures. After Boneh and Franklin proposed the first full functional identity based encryption scheme from the bilinear pairings in 2001, many other identity based schemes using pairings have been proposed. However, how to design a practical identity based encryption scheme that avoids using the pairings is still an open problem today. In this paper, after studying and combining the advantages of the traditional public key system and identity based system, we formally define a new Limited identity based system and present a concrete Limited identity based encryption scheme on a different complexity assumption. The resulting scheme is not only provably secure against the chosen plaintext attack in the random oracle, but also especially suitable for some practical system, such as an email system.