Stochastic Bounded Consensus Tracking of Second-Order Multi-Agent Systems with Measurement Noises based on Sampled-Data with Small Sampling Delay

Zhihai Wu,Li Peng,Linbo Xie,Jiwei Wen 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.1

This paper is devoted to the stochastic bounded consensus tracking problems of second-order multi-agent systems, where the control input of each agent can only use the information measured at the sampling instants from its neighbors or the virtual leader with a time-varying reference state, the measurements are corrupted by random noises, and the signal sampling process induces the small sampling delay. The augmented matrix method, the probability limit theory and some other techniques are employed to derive the necessary and sufficient conditions guaranteeing the mean square bounded consensus tracking. We show that the convergence of the proposed protocol simultaneously depends on the constant feedback gains, the network topology, the sampled period and the sampling delay, and that the static consensus tracking error depends on not only the above mentioned factors, but also the noise intensity and the upper bound of the velocity and the acceleration of the virtual leader. The obtained results cover no sampling delay as its one special case. Simulations are provided to demonstrate the effectiveness of the theoretical results.

Application of intelligent material in concrete for avoiding cracking

Zhihai Lin 한양대학교 세라믹연구소 2015 Journal of Ceramic Processing Research Vol.16 No.S1

Concrete cracking is usually attributed to thermal deformation, autogenous shrinkage, and drying shrinkages etc. Even though Expansive agent was adopted for a trial to compensate for the shrinkages, for a purpose of preventing the cracking, it was obvious that the expansive agent cannot always work well. In this study, the cracking sensitivity was evaluated by experiments of measuring full restraint stress, and free deformation were decomposed into thermal and non-thermal deformations. It was found that the expansive concrete adopting M type aggregate has a high performance on resisting cracking.

Copper nanoparticle incorporated plasmonic organic bulk-heterojunction solar cells

Liu, Zhihai,Lee, Seung Yong,Lee, Eun-Cheol American Institute of Physics 2014 APPLIED PHYSICS LETTERS Vol.105 No.22

Efficiency improvement in fullerene-layer-inserted organic bulk-heterojunction solar cells

Liu, Zhihai,Lee, Eun-Cheol American Institute of Physics 2012 JOURNAL OF APPLIED PHYSICS - Vol.111 No.2

Hapticity-Dependent Charge Transport through Carbodithioate-Terminated [5,15-Bis(phenylethynyl)porphinato]zinc(II) Complexes in Metal–Molecule–Metal Junctions

Li, Zhihai,Smeu, Manuel,Park, Tae-Hong,Rawson, Jeff,Xing, Yangjun,Therien, Michael J.,Ratner, Mark A.,Borguet, Eric American Chemical Society 2014 NANO LETTERS Vol.14 No.10

<P>Single molecule break junction experiments and nonequilibrium Green’s function calculations using density functional theory (NEGF-DFT) of carbodithioate- and thiol-terminated [5,15-bis(phenylethynyl)-10,20-diarylporphinato]zinc(II) complexes reveal the impact of the electrode-linker coordination mode on charge transport at the single-molecule level. Replacement of thiolate (−S<SUP>–</SUP>) by the carbodithioate (−CS<SUB>2</SUB><SUP>–</SUP>) anchoring motif leads to an order of magnitude increase of single molecule conductance. In contrast to thiolate-terminated structures, metal–molecule–metal junctions that exploit the carbodithioate linker manifest three distinct conductance values. We hypothesize that the magnitudes of these conductances depend upon carbodithoate linker hapticity with measured conductances across Au-[5,15-bis(4′-(dithiocarboxylate)phenylethynyl)-10,20-diarylporphinato]zinc(II)-Au junctions the greatest when both anchoring groups attach to the metal surface in a bidentate fashion. We support this hypothesis with NEGF-DFT calculations, which consider the electron transport properties for specific binding geometries. These results provide new insights into the origin of molecule-to-molecule conductance heterogeneity in molecular charge transport measurements and the factors that optimize electrode–molecule–electrode electronic coupling and maximize the conductance for charge transport.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2014/nalefd.2014.14.issue-10/nl502466a/production/images/medium/nl-2014-02466a_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl502466a'>ACS Electronic Supporting Info</A></P>

Changes of modal properties of simply-supported plane beams due to damages

Xiang, Zhihai,Zhang, Yao Techno-Press 2009 Interaction and multiscale mechanics Vol.2 No.2

Damage detection methods using structural dynamic responses have received much attention in the past decades. For bridge and offshore structures, these methods are usually based on beam models. To ensure the successful application of these methods, it is necessary to examine the sensitivity of modal properties to structural damages. To this end, an analytic solution is presented of the modal properties of simply-supported Euler-Bernoulli beams that contain a general damage with no additional assumptions. The damage can be a reduction in the bending stiffness or a loss of mass within a beam segment. This solution enables us to thoroughly discuss the sensitivities of different modal properties to various damages. It is observed that the lower natural frequencies and mode shapes do not change so much when a section of the beam is damaged, while the mode of rotation angle and curvature modes show abrupt change near the damaged region. Although similar observations have been reported previously, the analytical solution presented herein for clarifying the mechanism involved is considered a contribution to the literature. It is helpful for developing new damage detection methods for structures of the beam type.

The tap-scan method for damage detection of bridge structures

Xiang, Zhihai,Dai, Xiaowei,Zhang, Yao,Lu, Qiuhai Techno-Press 2010 Interaction and multiscale mechanics Vol.3 No.2

Damage detection plays a very important role to the maintenance of bridge structures. Traditional damage detection methods are usually based on structural dynamic properties, which are acquired from pre-installed sensors on the bridge. This is not only time-consuming and costly, but also suffers from poor sensitivity to damage if only natural frequencies and mode shapes are concerned in a noisy environment. Recently, the idea of using the dynamic responses of a passing vehicle shows a convenient and economical way for damage detection of bridge structures. Inspired by this new idea and the well-established tap test in the field of non-destructive testing, this paper proposes a new method for obtaining the damage information through the acceleration of a passing vehicle enhanced by a tapping device. Since no finger-print is required of the intact structure, this method can be easily implemented in practice. The logistics of this method is illustrated by a vehicle-bridge interaction model, along with the sensitivity analysis presented in detail. The validity of the method is proved by some numerical examples, and remarks are given concerning the potential implementation of the method as well as the directions for future research.

Effects of organic solvents for the phenyl-C61-butyric acid methyl ester layer on the performance of inverted perovskite solar cells

Liu, Zhihai,Xie, Xiaoyin,Lee, Eun-Cheol Elsevier Science B.V., Amsterdam. 2018 Organic electronics Vol.2018 No.56

High-performance metal-oxide-free perovskite solar cells based on organic electron transport layer and cathode

Liu, Zhihai,Xie, Xiaoyin,Liu, Guanchen,Lee, Eun-Cheol Elsevier 2019 Organic electronics Vol.64 No.-

<P><B>Abstract</B></P> <P>We introduced phenyl-C61-butyric acid methyl ester (PCBM) as an electron transport layer to improve the performance of metal-oxide-free perovskite solar cells (PSCs) using high-conductivity poly(3,4-ethylenedioxylenethiophene):poly(styrene sulfonate) (PEDOT:PSS) as the cathode. The work function of the PEDOT:PSS was tuned from −5.08 to −4.05 eV by using polyethylenimine, improving the electron collection. Using PCBM improved the electron transport and suppressed the charge recombination of the PSCs. The power-conversion efficiency (PCE) of the rigid PSCs (on glass substrates) was significantly improved from 12.5% to 13.9%, and the open-circuit voltage, short-circuit current density, and fill factor were improved simultaneously. The long-term stability of the PSCs was also improved: the PCE degradation of the PSCs without encapsulation decreased from 18.4% to 13.0% after 114 h. Using a 37-nm PCBM layer, the flexible PSCs on polyethylene naphthalate substrates exhibited a high PCE of 11.4% with good bendability. Our results indicate that using PCBM as an electron transport layer in metal-oxide-free PSCs is a feasible method for the large-scale roll-to-roll production of PSCs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> High-performance metal-oxide-free PSC produced with PCBM as electron transport layer. </LI> <LI> High PCE of 13.9% was achieved for rigid PSCs on a glass substrate. </LI> <LI> Long term stability of the PSCs was also improved upon using PCBM. </LI> <LI> Flexible PSCs on a PEN substrate exhibited a high PCE of 11.4% with good bendability. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

FA/Mel@ZnO nanoparticles as drug self-delivery systems for RPE protection against oxidative stress

Yi, Caixia,Yu, Zhihai,Sun, Xin,Zheng, Xi,Yang, Shuangya,Liu, Hengchuan,Song, Yi,Huang, Xiao Techno-Press 2022 Advances in nano research Vol.13 No.1

Drug self-delivery systems can easily realize combination drug therapy and avoid carrier-induced toxicity and immunogenicity because they do not need non-therapeutic carrier materials. So, designing appropriate drug self-delivery systems for specific diseases can settle most of the problems existing in traditional drug delivery systems. Retinal pigment epithelium is very important for the homeostasis of retina. However, it is vulnerable to oxidative damage and difficult to repair. Worse still, the antioxidants can hardly reach the retina by non-invasive administration routes due to the ocular barriers. Herein, the targeted group (folic acid) and antioxidant (melatonin) have been grafted on the surface of ZnO quantum dots to fabricate a new kind of drug self-delivery systems as a protectant via eyedrops. In this study, the negative nanoparticles with size ranging in 4~6 nm were successfully synthesized. They could easily and precisely deliver drugs to retinal pigment epithelium via eyedrops. And they realized acid degradation to controlled release of melatonin and zinc in retinal pigment epithelium cells. Consequently, the structure of retinal pigment epithelium cells were stabilized according to the expression of ZO-1 and β-catenin. Moreover, the antioxidant capacity of retinal pigment epithelium were enhanced both in health mice and photic injury mice. Therefore, such new drug self-delivery systems have great potential both in prevention and treatment of oxidative damage induced retinal diseases.