Harbin Institute of Technology

About: Harbin Institute of Technology is a education organization based out in Harbin, China. It is known for research contribution in the topics: Microstructure & Control theory. The organization has 88259 authors who have published 109297 publications receiving 1603393 citations. The organization is also known as: HIT.

Constructing Uniform Core-Shell PPy@PANI Composites with Tunable Shell Thickness toward Enhancement in Microwave Absorption.

Abstract: Highly uniform core–shell composites, polypyrrole@polyaniline (PPy@PANI), have been successfully constructed by directing the polymerization of aniline on the surface of PPy microspheres. The thickness of PANI shells, from 30 to 120 nm, can be well controlled by modulating the weight ratio of aniline and PPy microspheres. PPy microspheres with abundant carbonyl groups have very strong affinity to the conjugated chains of PANI, which is responsible for the spontaneous formation of uniform core–shell microstructures. However, the strong affinity between PPy microspheres and PANI shells does not promote the diffusion or reassembly of two kinds of conjugated chains. Coating PPy microspheres with PANI shells increases the complex permittivity and creates the mechanism of interfacial polarization, where the latter plays an important role in increasing the dielectric loss of PPy@PANI composites. With a proper thickness of PANI shells, the moderate dielectric loss will produce well matched characteristic impedanc...

Delay-dependent output-feedback stabilisation of discrete-time systems with time-varying state delay

Abstract: The output-feedback stabilisation problem is solved for discrete-time systems with time-varying delay in the state. A stability condition is first proposed, which is dependent on the minimum and maximum delay bounds. Based on this easily verifiable stability condition, the problems of stabilisation by static and dynamic output-feedback controllers are solved within the linear matrix inequality (LMI) framework. Since the obtained conditions for the existence of admissible controllers are not expressed as strict LMI conditions, the cone complementary linearisation procedure is exploited to solve the nonconvex feasibility problem. In addition, the obtained results, including stability analysis, static output-feedback stabilisation and dynamic output-feedback stabilisation are further extended to discrete time-delay systems with norm-bounded uncertain parameters. Numerical examples are also presented to illustrate the applicability of the developed results.

Is Sulfate Radical Really Generated from Peroxydisulfate Activated by Iron(II) for Environmental Decontamination

Abstract: It is well documented that the traditional Fenton reagent (ie, the combination of Fe(II) and H2O2) produces hydroxyl radical (•OH) under acidic conditions, while at near-neutral pH the reactive intermediate converts to ferryl ion (Fe(IV)) that can oxidize sulfoxides to produce corresponding sulfones, markedly differing from their •OH-induced products However, it remains unclear whether Fe(IV) is generated in the Fe(II) activated peroxydisulfate (PDS) process, where sulfate radical (SO4•-) is long recognized as the dominant intermediate in literature Here we demonstrated that SO4•- oxidized methyl phenyl sulfoxide (PMSO, a model sulfoxide) to produce biphenyl compounds rather than methyl phenyl sulfone (PMSO2) Interestingly, the formation of PMSO2 was observed when PMSO was treated by the Fe(II)/PDS system over a wide pH range, and the yields of PMSO2 were quantified to be ∼100% at acidic pH 3-5 The identification of Fe(IV) in the Fe(II)/PDS system could also reasonably explain the literature results on alcohol scavenging effect and ESR spectra analysis Further, a Fe(IV)-based kinetic model was shown to accurately simulate the experimental data This work urges re-evaluation of the Fe(II)/PDS system for environmental decontamination, given that Fe(IV) would have different reactivity toward environmental contaminants compared with SO4•- and/or •OH

Dynamic Data Operations with Deduplication in Privacy-Preserving Public Auditing for Secure Cloud Storage

Abstract: Cloud storage service has been increasing in popularity as cloud computing plays an important role in the IT domain. Users can be relieved of the burden of storage and computation, by outsourcing the large data files to the cloud servers. However, from the cloud service providers' point of view, it is wise to utilize the data deduplication techniques to reduce the costs of running large storage system and energy consumption on cloud servers. Based on the dynamic nature of data in the cloud storage system, we not only need to assure the data integrity with an auditing protocol supporting dynamic data operations for users, but also consider resorting to data deduplication techniques in the dynamic data operations for cloud service providers to achieve the goal of reducing costs. Thus, in this paper, we propose a mechanism that combines data deduplication with dynamic data operations in the privacy preserving public auditing for secure cloud storage. The analysis of security and performance shows that the proposed mechanism is highly efficient and provably secure.