Novel Organic/Inorganic Hybrid Star Polymer Surface-Crosslinked with Polyhedral Oligomeric Silsesquioxane

Jingyan Zhang,Dong Si,Shifeng Wang,Hao Liu,Xiaoming Chen,Haiou Zhou,Mingdi Yang,Guoying Zhang 한국고분자학회 2020 Macromolecular Research Vol.28 No.2

Novel organic/inorganic hybrid star polymer was prepared dually crosslinked within inner-core via divinylbenzene (DVB) and outer-surface via octafunctional polyhedral oligomeric silsesquioxane (POSS). Core cross-linked star polymers bearing dialkynyl-terminated polystyrene arms, (dialkynyl-PS)n-CCL, were synthesized at first by the atom transfer radical polymerization (ATRP) of DVB using α,α-dialkynyl-terminated PS macroinitiator, followed by the subsequent fractionation. Under high dilution conditions, (dialkynyl-PS)n-CCL was subjected to surface cross-linking with octa(3- azidopropyl) polyhedral oligomeric silsesquioxane, POSS-(N3)8, via click reaction, affording POSS-functionalized hybrid polymer doubly cross-linked within core and surface regions, SCL-(PS)n-CCL. FT-IR, 1H NMR, GPC, and elemental analysis results revealed that on average, the obtained hybrid polymer possesses a cross-linked PDVB inner core, ~14 linear PS arms (the MW per arm of 5.1 kDa), and ~4-5 POSS moieties at outer surface. Differential scanning calorimetry (DSC) thermograms and thermogravimetric analysis (TGA) revealed that after surface cross-linking the thermal stability of SCL-(PS)n-CCL is considerably improved. This work provides a proof-of-concept example for the preparation of dually cross-linked hybrid star polymer, which represents a novel category of organic/inorganic composite materials with unique chain architectures.

First-principles analysis of the absorption and luminescence properties of Cr2+-doped ZnSe crystal

Yuqin Zhang,Guoying Feng,Shenyu Dai,Shougui Ning,Shouhuan Zhou 한국물리학회 2016 Current Applied Physics Vol.16 No.5

The electronic band structure, absorption and luminescence properties of Cr2+-doped ZnSe crystal have been investigated by first-principles calculations on the basis of density functional theory. Firstprinciples calculations were carried out using the Vienna Ab-initio Simulation Package (VASP). It is shown that isolated impurity bands that mainly made up of Cr(d) orbitals are created in the band gap with the doping of Cr2+ ions. The Cr(d) orbitals are split into e and t2 groups because of the potential of the crystal. Theoretical absorption and luminescence spectra are calculated and compared with experimental data. An appropriate explanation of the experimental spectra is presented.

Structure of MnOx/TiO2 Catalysts and Their Catalytic Performance in the Gas-Phase Oxidation of o-Dichlorobenzene

Wenrui Zhang,Aidong Tang,Dabin Ren,Hui Xiang,Zhiqiang Yu,Guoying Sheng,Jiamo Fu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.5

The influence of structure of MnOx/TiO2 catalysts and their catalytic oxidation of o-dichlorobenzene were examined in this study. MnOx/TiO2 catalysts were characterized by X-ray diffractometer (XRD), thermogravimetry-differential thermal analysis (TG-DTA), TEM, X-ray photoelectron spectrum (XPS) and FTIR for NH3 adsorption techniques. Experimental results indicated that the MnOx/TiO2 catalyst prepared from manganese nitrate possessed the highest catalytic activity with a gas hourly space velocity (GHSV) of 14,500 h-1. This activity may be due to a large amount of surface Mn2O3 species, the strong Brönsted and Lewis acidity and the combined TiO2 phases. Additionally, a possible reaction model from o-dichlorobenzene oxidation over MnOx/TiO2 catalyst was suggested based on the analysis.

Rheological properties of fish skin collagen solution: Effects of temperature and concentration

Min Zhang,Yihui Chen,Guoying Li,Zongliang Du 한국유변학회 2010 Korea-Australia rheology journal Vol.22 No.2

To use collagen from freshwater fish skin as an alternative source of mammalian collagens for biomedical applications, we tested the rheological and structural properties of collagen from the skin of largefin longbarbel catfish (Mystus macropterus) by dynamic viscoelasticrheologimenteolFish skin collagen solution (FSCS) exhibited a sheor-thinning fedi behaMysr. The compllastiscosity (h*), loss tangent (tan d) and relaxic visc me of 1.5% FSCS decreased wies tkin ocrease of temperature. Also, tan d decreased wehaMythe relaxic visc me ocreased wies tkin ocrease of FSCS concentration. FSCS tiscconsider coymedicr stocon rhodulus (G'), loss hodulus (G"), h* tested and relaxic visc me and arus) by tan d teste tkaischose of bovine skin collagen solution (BSCS). Hdicver, FSCS behaMed wiesout regularity above 27.5oCi behtiowas in agreiment wies tkinisc me tkat tkindynamic denaturac viscemperature of thed collagen was approx mateoym29.5oC. Thes decreasedindicated tkat temperature and concentration ), ltococenols suitaconcfor isjusting FSCS tiscosity. The Arrhenius-typoce me-temperature superposition (TTS) was appliedCS tiisdition, tkinactitetion energy of 149.6KJ hol-1cfor 1.5% FSCS was calculated accor6KJ hentthe Arrhenius equation, indicatKJ ha weakby dntangliment effect amongal amongal amongal holeculeus (aischat amongal bovine skin collagen molecules, which was in agreement with the results from AFM measurement.

Properties of alkali-solubilized collagen solution crosslinked by N-hydroxysuccinimide activated adipic acid

Chen, Yihui,Zhang, Min,Liu, Wentao,Li, Guoying 한국유변학회 2011 Korea-Australia rheology journal Vol.23 No.1

The effect of N-hydroxysuccinimide activated adipic acid (NHS-AA) on the properties of alkali-solubilized collagen solutions was examined. The residual amino group content in crosslinked collagen, determined by trinitrobenzensulfonic acid (TNBS) assay, was decreased with increasing NHS-AA concentration. The results from differential scanning calorimeter (DSC) indicated that the maximum denaturation temperature ($T_d$) of crosslinked collagen solution was about $4.2^{\circ}C$ higher than that of un-crosslinked collagen solution ($36.6^{\circ}C$). Moreover, the values of storage modulus (G'), loss modulus (G") and complex viscosity (${\eta}^*$), obtained by means of dynamic frequency sweeps, were increased as NHS-AA concentration added up to 1.5 mM, and then decreased slightly when further increased NHS-AA concentration. Besides, for collagen solution crosslinked with 1.5 mM NHS-AA, dynamic denaturation temperature ($T_{dd}$) was about $1.1^{\circ}C$ lower than $T_d$ ($40.8^{\circ}C$), and the Arrhenius-type time-temperature superposition (TTS) principle was applied to yield the activation energy to be $474.4kJmol^{-1}$.

Effect of Grain Size Inhomogeneity of Ingot on Dynamic Softening Behavior and Processing Map of Al-8Zn-2Mg-2Cu alloy

Di Feng,Guoying Wang,Hongmei Chen,XinMing Zhang 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.1

The effect of grain size inhomogeneity of large ingot on the hot deformation behavior of Al-8Zn-2Mg-2Cu alloywere investigated using hot compression tests over a temperature range from 300 °C to 450 °C with strain rate from0.1 s-1to 10 s-1. It was found that the grain size (100 μm) in surface layer of the ingot is finer than that of the centrallayer (>200 μm). The surface specimen exhibited lower flow stress than that of central one in the temperature rangefrom 350 °C to 450 °C and the strain rate range from 0.1 s-1to 1 s-1. The softening mechanism is dynamic recovery,together with a partial dynamic recrystallization (DRX) at high temperature and low strain rate condition regardlessthe grain size. The nucleation mechanism of DRX is the strain induced grain boundary migration. Therefore,the DRX fraction is higher in surface specimen because the higher grain boundary density provides more nucleationsites. Based on processing maps, the applicable hot deformation parameters for the large size ingot are determinedto be at the temperature range of 440-450 °C and the strain rate of 0.1-0.3 s-1when taking the grain sizeinhomogeneity into account.

Comparison of ascorbate metabolism in fruits of two jujube species with differences in ascorbic acid content

Wang Yang,Song Guoying,Liang Dong,Xia Hui,Zhang Huifen,Luo Xian,Deng Qunxian 한국원예학회 2022 Horticulture, Environment, and Biotechnology Vol.63 No.5

Jujube fruits contain high levels of ascorbic acid (AsA). However, the AsA contents of fruits differ significantly in various jujube germplasm resources, and the factors responsible for these differences remain unknown. To explore the metabolic mechanism of AsA accumulation, we investigated the AsA content in fruits at different developmental stages of two jujube species, Ziziphus acidojujuba cv. Yuanxingxiaosuanzao (SZ) and Ziziphus jujuba Mill. cv. Luojiangtiaoyuanzao (LZ). The AsA accumulation pattern in the fruits of the two jujube species was similar during fruit development, and AsA content was negatively correlated with titratable acid. We also analysed the expression patterns of AsA metabolism genes. The results showed that AsA biosynthesis in jujube fruits was mainly related to the L-galactose pathway, as well as the inositol pathway. Furthermore, higher expression levels of genes involved in AsA biosynthesis (GME1, GMP1, GPP, GGP, and MIOX1) and regeneration (MDHAR1 and MDHAR2) were associated with higher AsA concentrations in SZ fruit compared with LZ fruit. In summary, we concluded that more efficient AsA biosynthesis and regeneration was responsible for the higher AsA accumulation in SZ fruit.

Properties of alkali-solubilized collagen solution crosslinked by N-hydroxysuccinimide activated adipic acid

Yihui Chen,Min Zhang,Wentao Liu,Guoying Li 한국유변학회 2011 Korea-Australia rheology journal Vol.23 No.1

The effect of N-hydroxysuccinimide activated adipic acid (NHS-AA) on the properties of alkali-solubilized collagen solutions was examined. The residual amino group content in crosslinked collagen, determined by trinitrobenzensulfonic acid (TNBS) assay, was decreased with increasing NHS-AA concentration. The results from differential scanning calorimeter (DSC) indicated that the maximum denaturation temperature (Td) of crosslinked collagen solution was about 4.2oC higher than that of un-crosslinked collagen solution (36.6℃). Moreover, the values of storage modulus (G'), loss modulus (G") and complex viscosity (η^*), obtained by means of dynamic frequency sweeps, were increased as NHS-AA concentration added up to 1.5mM, and then decreased slightly when further increased NHS-AA concentration. Besides, for collagen solution crosslinked with 1.5mM NHS-AA, dynamic denaturation temperature (T_(dd)) was about 1.1℃ lower than T_d (40.8℃), and the Arrhenius-type time-temperature superposition (TTS) principle was applied to yield the activation energy to be 474.4kJmol^(-1).

Room-temperature Synthesis of Cu2O Nanostructures and Their Morphology-dependent Adsorption Properties

Yanyan Xu,Ping Liu,Yanyan Cao,Yaqiu Sun,Guoying Zhang 대한화학회 2016 Bulletin of the Korean Chemical Society Vol.37 No.7

Three different Cu2O nanostructures, namely porous nanospheres, nanoparticles, and nanocubes, were synthesized through a facile solution route at room temperature. Structure and morphology of the products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FESEM), and nitrogen adsorption–desorption isotherms. The adsorption behavior of Methyl Orange (MO) onto these Cu2O nanostructures was investigated, considering the effect of initial methyl orange concentration and the additive amount of Cu2O products. The kinetic and equilibrium investigations suggested that the adsorption process of MO followed a pseudo-second order rate equation and the Langmuir isotherm model. The maximum adsorption capacity of the three samples followed the sequence: porous nanospheres > nanoparticles > nanocubes, which was in accordance of the BET specific surface of the samples. In addition, further investigations indicated that the as-prepared Cu2O nanostructures also show good adsorption properties for other anionic dyes including Congo red and Methyl blue.

Physiological response of red macroalgae Pyropia yezoensis (Bangiales, Rhodophyta) to light quality: a short-term adaptation

Xuefeng Zhong,Shuai Che,Congying Xie,Lan Wu,Xinyu Zhang,Lin Tian,Chan Liu,Hongbo Li,Guoying Du The Korean Society of Phycology 2023 ALGAE Vol.38 No.2

Light quality is a common environmental factor which influences the metabolism of biochemical substances in algae and leads to the response of algal growth and development. Pyropia yezoensis is a kind of economic macroalgae that naturally grows in the intertidal zone where the light environment changes dramatically. In the present study, P. yezoensis thalli were treated under white light (control) and monochromatic lights with primary colors (blue, green, and red) for 14 days to explore their physiological response to light quality. During the first 3 days of treatment, P. yezoensis grew faster under blue light than other light qualities. In the next 11 days, it showed better adaptation to green light, with higher growth rate and photosynthetic capacity (reflected by a higher rETR_max = 61.58 and E_k = 237.78). A higher non-photochemical quenching was observed in the treatment of red light than others for 14 days. Furthermore, the response of P. yezoensis to light quality also results in the difference of photosynthetic pigment contents. The monochromatic light could reduce the synthesis of all pigments, but the reduction degree was different, which may relate to the spectral absorption characteristics of pigments. It was speculated that P. yezoensis adapted to a specific or changing light environments by regulating the synthesis of pigments to achieve the best use of light energy in photosynthesis and premium growth and metabolism.