Harbin Engineering University

About: Harbin Engineering University is a education organization based out in Harbin, Heilongjiang, China. It is known for research contribution in the topics: Control theory & Microstructure. The organization has 31149 authors who have published 27940 publications receiving 276787 citations. The organization is also known as: HEU.

A Novel Adaptive Kalman Filter With Inaccurate Process and Measurement Noise Covariance Matrices

Abstract: In this paper, a novel variational Bayesian (VB)-based adaptive Kalman filter (VBAKF) for linear Gaussian state-space models with inaccurate process and measurement noise covariance matrices is proposed. By choosing inverse Wishart priors, the state together with the predicted error and measurement noise covariance matrices are inferred based on the VB approach. Simulation results for a target tracking example illustrate that the proposed VBAKF has better robustness to resist the uncertainties of process and measurement noise covariance matrices than existing state-of-the-art filters.

Template-assisted low temperature synthesis of functionalized graphene for ultrahigh volumetric performance supercapacitors.

Abstract: We demonstrated the fabrication of functionalized graphene nanosheets via low temperature (300 °C) treatment of graphite oxide with a slow heating rate using Mg(OH)2 nanosheets as template. Because of its dented sheet with high surface area, a certain amount of oxygen-containing groups, and low pore volume, the as-obtained graphene delivers both ultrahigh specific gravimetric and volumetric capacitances of 456 F g(-1) and 470 F cm(-3), almost 3.7 times and 3.3 times higher than hydrazine reduced graphene, respectively. Especially, the obtained volumetric capacitance is the highest value so far reported for carbon materials in aqueous electrolytes. More importantly, the assembled supercapacitor exhibits an ultrahigh volumetric energy density of 27.2 Wh L(-1), which is among the highest values for carbon materials in aqueous electrolytes, as well as excellent cycling stability with 134% of its initial capacitance after 10,000 cycles. Therefore, the present work holds a great promise for future design and large-scale production of high performance graphene electrodes for portable energy storage devices.

Structure control of polysaccharide derivatives for efficient separation of enantiomers by chromatography

Abstract: Chirality is a ubiquitous feature in living systems. Today, it is widely recognized that many biologically interesting compounds, such as drugs, agrochemicals, food additives, and fragrances, are chiral and their physiological properties usually rely on their chirality due to the extremely high chiral discrimination ability of enzymes and receptors.1-6 Particularly, the different pharmacological effects between enantiomers are ultimately an important concern in the pharmaceutical field in which only one enantiomer of a chiral drug often exhibits the desirable therapeutic activity, while the other shows an antagonistic function, side effects, or even toxic effects.7-14 During the late 1950s and early 1960s, a racemate of N-phthalylglutamic acid imide, which is a sedative and hypnotic drug known as thalidomide, was administrated to pregnant women and caused the birth of approximately 10 000 babies with malformations. Later, Blaschke pointed out that this teratogenic effect was attributed to the S-(-)isomer.15 Even though the administration of the pure R-(+)isomer could not halt the disaster because thalidomide is unstable in the body and easily undergoes racemization,16-18 this tragedy undoubtedly brought a profound movement in the drug administration and industries. In 1992, the U.S. Food and Drug Administration issued a specific guideline for the production of new chiral drugs,19 which demanded a systematic investigation of the biological behavior of their individual enantiomers and significantly encouraged the development of single enantiomer drugs.20-22 Today, most of the best-selling drugs around the world are administered as single enantiomers with the desired therapeutic activity,23 and the annual sales of single enantiomer drugs are expected to exceed 200 billion dollars in 2008. Furthermore, the preparation of single enantiomers has also become important in the fields of functional materials, such as ferroelectric liquid crystals and organic nonlinear optical molecules.24-26 Based on this historical background, substantial efforts have been undertaken to develop practical techniques for the preparation of enantiomers with a high enantiomeric excess (ee). In general, two approaches are utilized for this objective, asymmetric synthesis and chiral separation. Asymmetric synthesis using chiral sources, such as chiral pools, chiral auxiliaries, asymmetric catalysts, and enzymes, has significantly progressed over the last few decades.27-41 Although the large-scale preparation of enantiomers can be economically attained using this approach, the products do not always show a high ee, and therefore, a further purification step may be inevitable. Additionally, nature produces only one of the enantiomers as a chiral source in most cases. This means that if both enantiomers of the target compounds are required, at least two kinds of chiral sources are necessary for each enantiomer. However, it is sometimes difficult to obtain both of them. On the other hand, the chiral separation approach can easily provide both enantiomers with a high ee. Since Pasteur first isolated two enantiomers of sodium ammonium tartrate using a magnifying glass and a pair of tweezers in 1848,42,43 the innovation of chiral separation techniques has attracted great interest. Basically, chiral separations44 are carried out by (i) crystallization,45-47 (ii) enzymatic kinetic resolution,48-50 and (iii) chromatographic separation.51-53 Specifically, direct chiral separation using chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC) has significantly evolved during the past few decades and is recognized as the most popular and reliable tool for both the analysis of enantiomer compositions and the preparation of pure enantiomers.51-64 Chiral separations can * To whom correspondence should be addressed. Mailing address: EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 4648603, Japan. Phone: +81-52-789-4600. Fax: +81-52-789-3188. E-mail: okamoto@apchem.nagoya-u.ac.jp. † Nagoya University. ‡ Harbin Engineering University. Chem. Rev. 2009, 109, 6077–6101 6077

Fe3O4/TiO2 Core/Shell Nanotubes: Synthesis and Magnetic and Electromagnetic Wave Absorption Characteristics

Abstract: Fe3O4/TiO2 core/shell nanotubes are fabricated via a three-step process. α-Fe2O3 nanotubes are first obtained, and α-Fe2O3/TiO2 core/shell nanotubes are subsequently fabricated using Ti(SO4)2 as a Ti source by a wet chemical process. The thickness of the amorphous TiO2 shell is about 21 nm. After a H2 deoxidation process, the amorphous TiO2 layer changes into crystalline structures composed of TiO2 nanoparticles with an average diameter of 2.5 nm, and its thickness is decreased to about 18 nm. At the same time, α-Fe2O3 transforms into cubic Fe3O4. Consequently, crystalline Fe3O4/TiO2 core/shell nanotubes can be fabricated through the process above. The measurements of the magnetic properties demonstrate that the Fe3O4/TiO2 core/shell nanotubes exhibit ferromagnetic behavior at room temperature, and the Verwey temperature is about 120 K. The eddy current effect is largely reduced and the anisotropy energy is improved significantly for the core/shell nanotubes due to the presence of the TiO2 shells. The max...

Observer-Based Fault Detection for Nonlinear Systems With Sensor Fault and Limited Communication Capacity

Abstract: In this technical note, a new fault detection design scheme is proposed for interval type-2 (IT2) Takagi-Sugeno (T-S) fuzzy systems with sensor fault based on a novel fuzzy observer. The parameter uncertainties can be captured by the membership functions of the IT2 fuzzy model. The premise variables of the plant are perfectly shared by the fuzzy observer. A stochastic process between the plant and the observer is considered in the system. A fault sensitive performance is established, and then sufficient conditions are obtained for determining the fuzzy observer gains. Finally, simulation results are provided to verify the effectiveness of the presented scheme.