Preparation of Monodisperse Colloidal ZnO Nanoparticles and Their Optical Properties

Chong Yang,Limei Tang,Qingsong Li,Ailing Bai,Yanqiu Wang,Yingmin Yu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.5

Monodisperse colloidal zinc oxide (ZnO) nanospheres with a narrow size distribution were synthesized via a developed two-stage solution method. We controlled the size of the as-synthesized ZnO nanoparticles by varying the amount of ZnO/ethanol suspension added. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) revealed that the diameter of the as-synthesized ZnO nanoparticles was in the range of 60 – 140 nm with a polydispersity index less than 5%. On high-resolution TEM images, we clearly observed that the ZnO nanospheres were actually composed of tiny ZnO subunits, several nanometers in size. Powder X-ray diffraction and TEM-selected area electron diffraction analysis showed that the spheres consisted of polycrystalline nanoparticles. The size of the subunits, which was confirmed by ultraviolet (UV)-visible spectroscopy, increased as the amount of ZnO/ethanol suspension added was decreased. A UV emission at about 374 nm was observed, and this emission of ZnO nanoparticles is found to depend on particle size due to the confinement effect. A red emission at about 651 nm, which has been reported for undoped ZnO, appeared due to the excess oxygen on the particles from O – H or C=O groups. The intensity of the red emission increased as the relative oxygen content increased. The formation mechanism of such ZnO nanospheres was also considered.

Gear dynamic modelling based on the concept of dynamic mesh stiffness: theoretical study and experimental verification

Chongyang Xie,Wei Yu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.10

Gear mesh stiffness (GMS) is considered as one of the most important internal excitations affecting the dynamic response of the gear transmission system. In most gear dynamic model established by the lumped parameter method, the GMS is pre-calculated under static condition, and treated as a kind of known input of the gear dynamic model. However, the actual tooth contact state under dynamic operation condition is rather different from that under static condition, which means the variation of GMS should also be evaluated dynamically. In this paper, a new gear dynamic model is established based on the lumped parameter method, where the real-time GMS is used. To validate the proposed gear dynamic model, simulated result has been compared with the experiment result that reported in the literature, and it shows that the proposed gear dynamic model is more reasonable for gear dynamic response prediction.

The Shearing Behavior of Artificial Soil Extracted from Loess

( Chongyang Gao ),( Ling Xu ),( Dongdong Yan ),( Yili Wang ),( Borui Lv ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2

Loess, as a typical silty soil, covered an area of 440,000km2 in China and a lot of work has been done on the study of mechanics and microstructure of the Loess. For better understanding the behavior of Loess, artificial soils we're created by extracting from the Xi’an and Lanzhou loess using water sedimentary method and which were then divided into five groups according to the variation of gradation. A series of triaxial tests were conducted to identify the effect of particle gradation on the behavior of soil within the framework of critical state soil mechanics. The results show that the location of critical state line is first decrease and then increased with the content of the fine particles increasing. And the slope of the critical state lines also shows consistent trend. There exists a phase transformation gradation soil, called C soil, which is the closest to the natural soil on the gradation curve. For A and B soils with more clay content, there are relatively difficult to reach critical state even if their strain reaches 35%, compared to the other types of soil. As the content of coarse particles increases, the soil generally exhibits more pronounced dilatancy, and the properties are closer to fine sand. This paper is of great significance to provide a reference for better understanding of the behavior of loess in the geotechnique engineering application.

Dental Pulp Stem Cells derived Conditioned Medium Promotes Angiogenesis in Hindlimb Ischemia

ChongYang Shen,Lin Li,Ting Feng,JinRong LI,MeiXing Yu,Qiao Lu,Hong Li 한국조직공학과 재생의학회 2015 조직공학과 재생의학 Vol.12 No.1

Paracrine effects of mesenchymal stem cells (MSCs) have been suggested play an important role in thetreatment of ischemic diseases. Dental pulp Stem cells (DPSCs) share many properties with MSCs. However, thebeneficial effects of DPSCs on ischemic diseases remain to be elucidated. The present study, we found that DPSCssecreted higher levels angiogenic factors of VEGF, SDF-1, MCP-1 and PDGF-BB compared with AD-MSCs. Wethen investigated whether DP-CM can induce the migration of vascular smooth muscle cells (VSMCs) and humanumbilical venous endothelial cells (HUVECs) in vitro. Under hypoxia, the apoptosis of HUVECs was inhibitedwhile survival was improved by treatment of DP-CM. In a H2O2-induced cell death assay, DP-CM also significantlyreduced HUVECs oxidative stress compare to control group. The tube formation assay demonstrated that the DPCMgroup had a greater angiogenic potential than control medium. Results in the mouse model showed both thelaser Doppler perfusion index and the relative number of CD31 positive microvessels to be significantly higher inthe DP-CM group than in the control group [(77%±11%) vs. (45%±6%), and (6.2±1.1)/HPF vs. (2.3±0.3)/HPF]. Inthis way, the use of DP-CM may be a suitable means of treating ischemic diseases.

High-performance metal oxide-free inverted perovskite solar cells using poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine) as the hole transport layer

Xu, Chongyang,Liu, Zhihai,Lee, Eun-Cheol The Royal Society of Chemistry 2018 Journal of Materials Chemistry C Vol.6 No.26

<P>In this work, we used poly(3,4-ethylenedioxylenethiophene):poly(styrene sulfonate) (PEDOT:PSS, PH 1000) and poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine) (PTAA) as anode and hole transport materials, respectively, for fabricating metal oxide-free inverted perovskite solar cells (PSCs). The sheet resistance of the PEDOT:PSS (PH 1000) anode was reduced to 76 Ω sq<SUP>−1</SUP> after treatment with ethylene glycol and phosphoric acid, a level comparable to that of conventional indium tin oxide. The hydrophobicity of PTAA improved the perovskite crystallization, facilitating performance improvements in the PSCs. A high power conversion efficiency (PCE) of 14.23% was achieved for these structured rigid PSCs on a rigid glass substrate, with the short-circuit current density, open-circuit voltage, and fill factor of 19.88 mA cm<SUP>−2</SUP>, 1.02 V, and 70.2%, respectively. Flexible PSCs on a polyethylene terephthalate substrate exhibited a high PCE of 10.51% with excellent bendability. Our results indicate that using anodes of PEDOT:PSS (PH 1000) and hole transport layers of PTAA presents a promising fabrication method for high-performance rigid and flexible metal oxide-free PSCs, which suggests future large-scale and roll-to-roll production.</P>

Fabricated Ag/Ag2S/reduced graphene oxide composite photocatalysts for enhancing visible light photocatalytic and antibacterial activity

Pengwei Huo,Chongyang Liu,Dongyao Wu,Jingru Guan,Jinze Li,Huiqin Wang,Qi Tang,Xiuying Li,Yongsheng Yan,Shouqi Yuan 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.57 No.-

In this work, we reported one kind of photocatalytic and antibacterial materials, Ag/Ag2S/reducedgraphene oxide (rGO), which prepared by the hydrothermal and UV-light-assisted reduction methods. The Ag2S nanoparticals were well dispersed on the surface of rGO as revealed by series ofcharacterization. The obtained Ag/Ag2S/rGO photocatalyst showed excellent photocatalytic degradationefficiency of 87.6% for ciprofloxacin (CIP) under visible light irradiation and outstanding antibacterialactivity for Escherichia coli (E. coli) which reached to 97.76% in 24 h. The trapping of active species showedthat the hydroxyl radicals, holes and superoxide radicals played important roles in the photocatalyticdegradation of CIP processes.

Investigation of random fatigue life prediction based on artificial neural network

Jie Xu,Chongyang Liu,Xingzhi Huang,Yaolei Zhang,Haibo Zhou,Hehuan Lian 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.46 No.3

Time domain method and frequency domain method are commonly used in the current fatigue life calculation theory. The time domain method has complicated procedures and needs a large amount of calculation, while the frequency domain method has poor applicability to different materials and different spectrum, and improper selection of spectrum model will lead to large errors. Considering that artificial neural network has strong ability of nonlinear mapping and generalization, this paper applied this technique to random fatigue life prediction, and the effect of average stress was taken into account, thereby achieving more accurate prediction result of random fatigue life.

Decolorization and Biodegradation of the Azo Dye Congo Red by an Isolated Acinetobacter baumannii YNWH 226

Xun-an Ning,Chongyang Yang,Yujie Wang,Zuoyi Yang,Jingyu Wang,Ruijing Li 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.4

A strict aerobic Acinetobacter baumanniiYNWH 226, isolated from an activated sludge reactortreating textile wastewater, was able to grow on Congo redas the sole carbon source under aerobic conditions. Thedecolorization and TOC reduction efficiency were 99.1 and93.72%, respectively. The effects of the Congo redconcentration were studied. The environmental factors (i.e.,pH, temperature and agitation speed) on the biodegradationof Congo red in aqueous phase were studied and evaluatedusing response surface methodology. The results indicatedthat when the Congo red concentration was 100 mg/L, theoptimal decolorization conditions were as follows: 37°C,pH 7.0 and 180 rpm. The single A. baumannii YNWH 226was able to form aromatic amines by reductive breakage ofthe azo bond and then oxidize them into non-toxicmetabolites.

Effects of G-Rh2 on mast cell-mediated anaphylaxis via AKT-Nrf2/NF-κB and MAPK-Nrf2/NF-κB pathways

Chang Xu,Liangchang Li,Chongyang Wang,Jingzhi Jiang,Li Li,Lianhua Zhu,Shan Jin,Zhehu Jin,Jung Joon Lee,Guanhao Li,Guanghai Yan 고려인삼학회 2022 Journal of Ginseng Research Vol.46 No.4

Background: The effect of ginsenoside Rh2 (G-Rh2) on mast cell-mediated anaphylaxis remains unclear. Herein, we investigated the effects of G-Rh2 on OVA-induced asthmatic mice and on mast cell-mediatedanaphylaxis. Methods: Asthma model was established for evaluating airway changes and ear allergy. RPMCs and RBL-2H3 were used for in vitro experiments. Calcium uptake, histamine release and degranulation weredetected. ELISA and Western blot measured cytokine and protein levels, respectively. Results: G-Rh2 inhibited OVA-induced airway remodeling, the production of TNF-a, IL-4, IL-8, IL-1b andthe degranulation of mast cells of asthmatic mice. G-Rh2 inhibited the activation of Syk and Lyn in lungtissue of OVA-induced asthmatic mice. G-Rh2 inhibited serum IgE production in OVA induced asthmaticmice. Furthermore, G-Rh2 reduced the ear allergy in IgE-sensitized mice. G-Rh2 decreased the earthickness. In vitro experiments G-Rh2 significantly reduced calcium uptake and inhibited histaminerelease and degranulation in RPMCs. In addition, G-Rh2 reduced the production of IL-1b, TNF-a, IL-8, andIL-4 in IgE-sensitized RBL-2H3 cells. Interestingly, G-Rh2 was involved in the FcεRI pathway activation ofmast cells and the transduction of the Lyn/Syk signaling pathway. G-Rh2 inhibited PI3K activity in adose-dependent manner. By blocking the antigen-induced phosphorylation of Lyn, Syk, LAT, PLCg2, PI3KERK1/2 and Raf-1 expression, G-Rh2 inhibited the NF-kB, AKT-Nrf2, and p38MAPK-Nrf2 pathways. However, G-Rh2 up-regulated Keap-1 expression. Meanwhile, G-Rh2 reduced the levels of p-AKT,p38MAPK and Nrf2 in RBL-2H3 sensitized IgE cells and inhibited NF-kB signaling pathway activation byactivating the AKT-Nrf2 and p38MAPK-Nrf2 pathways. Conclusion: G-Rh2 inhibits mast cell-induced allergic inflammation, which might be mediated by theAKT-Nrf2/NF-kB and p38MAPK-Nrf2/NF-kB signaling pathways

Fabrication of Ag/In2O3/TiO2/HNTs hybrid-structured and plasma effect photocatalysts for enhanced charges transfer and photocatalytic activity

Huiqin Wang,Dongyao Wu,Chongyang Liu,Jingru Guan,Jinze Li,Pengwei Huo,XINLIN LIU,Qian Wang,Yongsheng Yan 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.67 No.-

The purpose of this work designed hybrid-structured and plasma effect photocatalyst of Ag/In2O3/TiO2/HNTs via sol–gel and photo-reduction methods. The structures, morphologies, optical and photoelectric performances of as-prepared photocatalysts were characterized via XRD, TEM, XPS, BET, UV–vis DRS, PL and photocurrents. The photocatalytic activity was evaluated by degradation of TC. The results showed that the hybrid-structure and plasma effect can effectively cause the multi-transfer of electrons and increase the separation rate of electron and hole pairs which obtained high photocatalytic activity. The photocatalytic degradation processes reveal that O2− and h+ are major active species.