Effect of Tea Polysaccharides on Thermal and Pasting Properties of Wheat Starch

Haihua Zhang,Shikang Zhang,Chunyuan Zhang,Yuejin Zhu,Yunyun Huang 한국차학회 2015 한국차학회지 Vol.- No.S

The thermal and pasting properties of wheat starch (WS)/tea polysaccharides (TPS) composite system were investigated. Significant increases of transition temperatures (To, Tp, Tc) and the enthalpy of gelatinization (ΔH1) of WS/TPS (2 wet% and 4 wet%) were found as TPS content increased. The lower ΔH2 (endothermic enthalpy under reheating) and R2 (degree of retrogradation of WS) were also detected in WS/TPS in storage of 3,7,14 days when compared with those of WS. The agreements were shown by RVA with the lower total setback and by Texture Analyzer with lower gel firmness. The results of TPS affecting the thermal and pasting properties could be generally explained with Avrami equation of WS/TPS. The Avrami equation exposed that TPS affect the primary nucleation in early stage and the decreased nucleation rate announced by the constant k. The overall results demonstrated that the TPS has an inhibitory effect on the recrystallization of pasting WS in storage.

A New Result on the Stability and Convergence of Self-tuning Adaptive Control

Weicun Zhang,Yuejin Song,Jiwei Liu 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

Among various types of self-tuning control schemes, only one-step-ahead self-tuning control of deterministic plant and minimum variance self-tuning control of stochastic plant can guarantee the stability and convergence of closed-loop system without requiring the convergence of parameter estimation. This paper presents a new result that the convergence of parameter estimates is not necessary for the stability and convergence of a general self-tuning control system comprising of any admissible control strategy and any admissible parameter estimation algorithm. This breakthrough result is owing to the adoption of a new type of virtual equivalent system: slow switching control system, whose stability and tracking performance are guaranteed under mild conditions.

Study of the Permeability of Tomato Pericarp Etched by Low-energy Ion Beams Based on α-particles Irradiation

Lili Zhang,Lianyun Chen,Xue Xu,Qing Huang,Yuejin Wu 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.3

Low-energy ion beam bio-technology has been applied in the biological field and has gained remarkable success in crop and microbe breeding. However, to understand how low-energy ion beams interact with biological materials remains a challenge for researchers who work for the development of ion-beam bio-technology. In this work,tomato pericarp was used as the target sample to study the effect of ion beams on the permeability of biological objects. A series of experiments were conducted via irradiating tomato pericarp samples with low-energy (10 keV ~ 25 keV)ion beams followed by measuring the pericarp’s permeability using transmissive α particles. The transmissive spectra of α particles and the measurement of the tip number in CR39gave a quantitative evaluation of the sputtering effect caused by low-energy ions. Meanwhile, natural red dye was used to examine the permeability of irradiated tomato pericarp samples. It was found that the sputtering effect is not only proportional to the ion energy and dose, but dependent on the ion type as well. The damage caused by Ar ions due to sputtering was much more severe than that caused by N ions sputtering with the same dose. Therefore,this study not only demonstrates the permeability difference of biological membranes before and after ion irradiation,but also provides the information on how to optimize the experimental conditions for application of the low-energy ion beam in biology.

A Stability Criterion for Weighting Multiple Model Adaptive Control

Weicun Zhang,Xiaobo Wang,Yuejin Song 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

Based on virtual equivalent system concept and methodology, a criterion on the stability of weighting multiple model adaptive control (MMAC) of linear time-invariant discrete plant is presented. The obtained result indicates that the stability of weighting MMAC depends mainly on the convergence of posterior probability evaluator which represents an identification subsystem in a weighting multiple model adaptive control system. For that a general weighting MMAC with arbitrary controller design strategy and arbitrary algorithm of posterior probability evaluation is considered, we believe that virtual equivalent system concept and methodology could be a potential approach towards a general theory of weighting multiple model adaptive control.

Three-Dimensional Hierarchically Ternary Iron Tungsten Nitride Nanosheets with Slight Ratio of Nickel Modulation for Oxygen Evolution Reaction

Xuyang Zhang,Hangjia Shen,Babak Rezaei Moghadam,Siqi Liu,Yuejin Zhu,Jiacheng Wang,Minghui Yang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.7

Practical application of oxygen evolution reaction (OER) in energy conversion devices, such as water splitting and metal-air batteries, relies on the development of highly efficient and stable electrocatalysts and is still challengeable. Here, Nickel modulated ternary Iron tungsten nitride (Ni-FeWN2) nanosheets are synthesized through a facile hydrothermal growth method and subsequently nitriding process for boosting OER. A potential of 1.57V at the current density of 10 mA/cm2 and Tafel slope (40 mV/dec) are achieved on Ni-FeWN2, much lower than that on Ni-free FeWN2 and commercial IrO2. More importantly, Ni-FeWN2 nanosheets display high stability and electrocatalytic activity toward driving oxygen evolution efficiently in alkaline media.

Positive solutions for a three-point fractional boundary value problems for p-Laplacian with a parameter

Yitao Yang,Yuejin Zhang 한국전산응용수학회 2016 Journal of applied mathematics & informatics Vol.34 No.3

In this paper, we firstly use Krasnosel'skii fixed point theorem to investigate positive solutions for the following three-point boundary value problems for $p$-Laplacian with a parameter $$(\phi_{p}(D_{0^{+}}^{\alpha}u(t)))'+\lambda f(t,u(t))=0,\ \ \ 0<t<1,$$ $$D_{0^{+}}^{\alpha}u(0)=u(0)=u''(0)=0,\ \ \ u'(1)=\gamma u'(\eta),$$ where $\phi_{p}(s)=|s|^{p-2}s,\ p>1,\ D_{0^{+}}^{\alpha}$ is the Caputo's derivative, $\alpha\in (2,3],\ \eta,\gamma\in (0,1), \lambda>0$ is a parameter. Then we use Leggett-Williams fixed point theorem to study the existence of three positive solutions for the fractional boundary value problem$$(\phi_{p}(D_{0^{+}}^{\alpha}u(t)))'+f(t,u(t))=0,\ \ \ 0<t<1,$$ $$D_{0^{+}}^{\alpha}u(0)=u(0)=u''(0)=0,\ \ \ u'(1)=\gamma u'(\eta),$$ where $\phi_{p}(s)=|s|^{p-2}s,\ p>1,\ D_{0^{+}}^{\alpha}$ is the Caputo's derivative, $\alpha\in (2,3],\ \eta,\gamma\in (0,1).$

POSITIVE SOLUTIONS FOR A THREE-POINT FRACTIONAL BOUNDARY VALUE PROBLEMS FOR P-LAPLACIAN WITH A PARAMETER

YANG, YITAO,ZHANG, YUEJIN The Korean Society for Computational and Applied M 2016 Journal of applied mathematics & informatics Vol.34 No.3

In this paper, we firstly use Krasnosel'skii fixed point theorem to investigate positive solutions for the following three-point boundary value problems for p-Laplacian with a parameter $({\phi}_P(D^{\alpha}_{0}+u(t)))^{\prime}+{\lambda}f(t, u(t))=0$, 0<t<1, $D^{\alpha}_{0}+u(0)=u(0)=u{\prime}{\prime}(0)=0$, $u^{\prime}(1)={\gamma}u^{\prime}(\eta)$ where ϕ_p(s) = |s|^p⁻²s, p > 1, $D^{\alpha}_{0^+}$ is the Caputo's derivative, α ∈ (2, 3], η, γ ∈ (0, 1), λ > 0 is a parameter. Then we use Leggett-Williams fixed point theorem to study the existence of three positive solutions for the fractional boundary value problem $({\phi}_P(D^{\alpha}_{0}+u(t)))^{\prime}+f(t, u(t))=0$, 0<t<1, $D^{\alpha}_{0}+u(0)=u(0)=u{\prime}{\prime}(0)=0$, $u^{\prime}(1)={\gamma}u^{\prime}(\eta)$ where ϕ_p(s) = |s|^p⁻²s, p > 1, $D^{\alpha}_{0^+}$ is the Caputo's derivative, α ∈ (2, 3], η, γ ∈ (0, 1).

DELAY-DEPENDENT GLOBAL ASYMPTOTIC STABILITY ANALYSIS OF DELAYED CELLULAR NEURAL NETWORKS

Yitao Yang,Yuejin Zhang 한국전산응용수학회 2010 Journal of applied mathematics & informatics Vol.28 No.3

In this paper, the problem of delay-dependent stability analysis for cellular neural networks systems with time-varying delays was considered. By using a new Lyapunov-Krasovskii function,delay-dependant stability conditions of the delayed cellular neural networks systems are proposed in terms of linear matrix inequalities (LMIs). Examples are provided to demonstrate the reduced conservatism of the proposed stability results.

DELAY-DEPENDENT GLOBAL ASYMPTOTIC STABILITY ANALYSIS OF DELAYED CELLULAR NEURAL NETWORKS

Yang, Yitao,Zhang, Yuejin The Korean Society for Computational and Applied M 2010 Journal of applied mathematics & informatics Vol.28 No.3

In this paper, the problem of delay-dependent stability analysis for cellular neural networks systems with time-varying delays was considered. By using a new Lyapunov-Krasovskii function, delay-dependant stability conditions of the delayed cellular neural networks systems are proposed in terms of linear matrix inequalities (LMIs). Examples are provided to demonstrate the reduced conservatism of the proposed stability results.

Light scattering enhanced photoanodes for dye-sensitized solar cells prepared by carbon spheres/TiO_2 nanoparticle composites

Guangtao Yang,Jing Zhang,Peiqing Wang,Qiang Sun,Jun Zheng,Yuejin Zhu 한국물리학회 2011 Current Applied Physics Vol.11 No.3

Incorporating scattering centers in the nanocrystalline photoanode or additional scattering layers on the nanocrystalline photoanode is an effective way to enhance the light harvest efficiency (LHE) of the photoanode and the performance of dye-sensitized solar cells (DSSCs). In this work, mesoporous photoanodes were fabricated based on the composites of anatase TiO_2 nanoparticles and carbon spheres. The holes were left after calcination thus serving as the light scattering centers in the photoanode. The size and the amounts of the holes were adjusted by changing the size (250, 500 and 700 nm) and concentration (5, 10, 15 and 20 wt% of the TiO_2 nanocrystallines) of the carbon spheres in the slurry. The light scattering ability and the dye adsorption of the photoanodes with holes of varied size and contents were investigated. The holes left by calcinating the carbon spheres increased the light scattering of the photoanode. However, the increased light scattering ability offset the dye adsorption ability of the photoanode by high amounts of carbon spheres modification. The performances of the DSSCs are investigated under the simulated sunlight and the incident light (400―780 nm). The DSSC with photoanode made from the slurry with 500 nm and 15 wt% carbon spheres exhibited the opitimized performance (Jsc = 14.8 mA cm^-2, Voc = 0.657 V, FF = 0.703 and η = 7.2%), much better than the DSSCs with photoanode made by the pure TiO_2 nanocrystalline (Jsc = 11.7 mA cm^-2, Voc = 0.645V, FF = 0.699 and η = 5.55%) and other photoanodes, indicating it best balanced the controversy of the enhanced light scattering ability and the decreased dye adsorption. The incident-photo-to-electric conversion efficiency test indicated the highest LHE of the 500 nm and 15 wt% carbon spheres modified photoanode.