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Robust Stabilization of Switched Positive Linear Systems with Uncertainties
Junfeng Zhang,Zhengzhi Han 제어·로봇·시스템학회 2013 International Journal of Control, Automation, and Vol.11 No.1
This paper investigates the robust stabilization of a class of switched positive linear systems. The uncertainties of system models refer to the interval and polytopic uncertainty. By using the multiple linear copositive Lyapunov functions approach and linear programming approache, the robust sta-bilization of those systems in the autonomous form with uncertainties is studied. Further, the control synthesis of those systems in the non-autonomous form with uncertainties is addressed. Finally, a simulating example illustrates the validity of the design.
Liu, Tonghuan,Fang, Jian,Zhang, Yaping,Zeng, Zhengzhi The Polymer Society of Korea 2008 Macromolecular Research Vol.16 No.8
A series of pH and temperature-responsive (N,N-diethylacrylamide-co-methylacrylic acid) copolymers were synthesized by radical copolymerization and characterized by elemental analysis, Fourier-transform infrared (FT-IR), nuclear magnetic resonance (NMR) $^1H$, $^{13}C$ and LLS. The effects of salt and pH on the phase transition behaviors of the copolymers were investigated by uv. With increasing NaCl concentration, significant salt effects on their phase transition behaviors were observed. UV spectroscopic studies showed that the phase transition became faster with increasing NaCl concentration. In addition, the phase transition behaviors of copolymers were sensitive to pH. The pH and temperature sensitivity of these copolymers would make an interesting drug delivery system.
Cao, Yongkai,Sun, Ningning,Zhang, Jiumei,Liu, Zhiguo,Tang, Yi-zhe,Wu, Zhengzhi,Kim, Kyeong-Man,Cheon, Seung Hoon The Royal Society of Chemistry 2018 MedChemComm Vol.9 No.9
<P>The dopamine D3 receptor (D3R) is a proven therapeutic target for the treatment of neurological and neuropsychiatric disorders. In particular, D3R-selective ligands that can eliminate side effects associated with dopamine D2 receptor (D2R) therapeutics have been validated. However, the high homology in signaling pathways and the sequence similarity between D2R and D3R have rendered the development of D3R-selective ligands challenging. Herein, we designed and synthesized a series of piperazine-phthalimide bitopic ligands based on a fragment-based and molecular docking inspired design. Compound 9i was identified as the most selective D3R ligand among these bitopic ligands. Its selectivity was improved compared to reference compounds 1 and 2 by 9- and 2-fold, respectively, and it was 21-fold more potent than compound 2. Molecular docking demonstrated that the orientation of Leu<SUP>2.64</SUP> and Phe<SUP>7.39</SUP> and the packing at the junction of helices may affect the specificity for D3R over D2R. Functional evaluation revealed that D3R-selective ligand 9i displayed a subpicomolar agonist activity at D3R with a 199-fold increase in potency compared to quinpirole. These results may be useful for the fragment-based design of bitopic compounds as selective D3R ligands.</P>
Molecularly Imprinted Polymer Coating with Fluorescence on Magnetic Particle
Jing Huang,Haiqing Liu,Haifen Men,Yunyun Zhai,Qihui Xi,Zulei Zhang,Jian Zhang,Zhengzhi Yin,Lei Li 한국고분자학회 2013 Macromolecular Research Vol.21 No.9
In this research, molecular imprinting technology was employed to prepare magnetic, fluorescent molecularly imprinted polymer microspheres (fluorescent M-MIP) for recognition and separation of endocrine disrupting chemicals. The fluorescent M-MIP were prepared using Fe3O4@SiO2 magnetic nanoparticles combined with fluorescein (isothiocyanate) as fluorescent material with the surface molecularly imprinting method. The magnetic fluorescent molecularly imprinted polymers were characterized by fluorescence spectrophotometer, X-ray powder diffraction,vibration sample magnetic field meter, scanning and transmission electron microscopic methods. The results showed that the fluorescent M-MIP not only had excellent superparamagnetism and maintained the crystalline structure of the magnetic nanoparticles, but also stable fluorescence. The recognition selectivity of the magnetic fluorescence polymer was studied for template molecule and analogues. The results indicated that the fluorescent quenches of bisphenol A (the selective target) for fluorescent M-MIP were higher than that of the structural analogues, which illustrated the recognition selectivity for bisphenol A. Simultaneously, the fluorescent magnetic non-imprinted polymers (M-NIPs) had much higher fluorescent quenches than the fluorescent M-NIPs in the processes of rebinding. Therefore, the fluorescent M-MIP technology can be used for the recognition, magnetic separation and detection of bisphenol A by fluorescence spectrometry without any time-consuming elution.
Peng Wan,Huixiang Yu,Feng Li,Pengfei Gao,Lei Zhang,Zhengzhi Zhao 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.10
The hot deformation behavior of low-density high-strength Fe–Mn–Al–C alloy steel at T = 900-1150 °C and ̇ = 0.01-10 s−1was studied by the Gleeble-3500 thermo-mechanical simulator. The rheological stress curve characteristics of the steel wereanalyzed through experimental data, and a physical constitutive model considering strain coupling was established. At thesame time, the finite element software DEFORM was used to calculate the critical damage value of the steel, and the influenceof T and ̇ on the maximum damage value was considered. By introducing the dimensionless parameter Zener–Hollomon, thecritical damage model was established. Finally, the workability of the steel was evaluated by using the intuitive processingmap technology. The results indicated that Fe–Mn–Al–C alloy steel is a positive strain rate-sensitive and a negative temperature-sensitive material, and the constitutive model considering physical parameters can well predict the rheological stress ofthe steel during hot deformation (R = 0.997). The critical damage factor of Fe–Mn–Al–C alloy steel varies with the changeof T and ̇ , and the range is 0.359-0.535. At the same time, the critical damage factor is more sensitive to ̇ . At a constantT, the damage factor decreases with the increase of ̇ . Based on the Prasad instability criterion, the dynamic material modelprocessing map and the microstructure verification after thermal compression, the rheological instability characteristics ofthe steel are mainly mechanical instability and local plastic flow, and the stable deformation area is mainly characterized bydynamic recrystallization. The optimal hot working process window of the steel is 975-1050 °C/0.01-0.032 s−1.