A novel scheme to acquire enhanced up-conversion emissions of Ho3+ and Yb3+ co-doped Sc2O3

Chaoyi Zhang,Qian Jiang,Xinyu Wang,Jing Liu,Yantao Xiao,Chun Li,Hai Lin,Fanming Zeng,Zhongmin Su 한국물리학회 2020 Current Applied Physics Vol.20 No.1

A detailed investigation about the effect of Sc2O3: 1 mol%Ho3+/5 mol%Yb3+ co-doped with Ce4+ ions prepared by sol-gel methods was performed systematically. Under the excitation of 980 nm laser diode, both green emission (553 nm, 5F4/5S2→5I8) and red emission (672 nm, 5F5→5I8) were both observed in the emission spectra of the samples, which were found to be two-photon process and sensitized by Yb3+ ions. With the increasing of Ce4+ ions, the up-conversion green emission intensity are increased by 6.52, 8.69, 10.85, 13.92 and 16.66 fold, corresponding to the Ce4+ ions concentrations from 5 mol% to 13 mol%, respectively. The number of photons are necessary to populate the upper emitting state decreases to 2 and the infrared absorption coefficient is reduced, when the Ce4+ ions concentration increase to 13 mol%. Ce4+ ions play an important role in tailoring the local crystal field around Ho3+ ions, lowering the highest phonon cut-off energy of matrix and reducing the infrared absorption coefficient, thus hindering the non-radiative processes, which contribute to the increased emission intensity. The excellent enhancement makes it a promising multifunctional optical luminescence material.

A Simple Switched Capacitor Compensator to Minimize Zero-Crossing Distortion in Single-Phase PFC Converters

Yan Zhang,Jinjun Liu,Chaoyi Zhang 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

This paper explorers techniques for minimizing zero-crossing distortion in single-phase PFC converters from the angle of topologies. Zero-crossing distortions of typical single-phase PFC topologies are compared in theory to reveal that cusp distortion is predominant responsible for zero-crossing distortion. PWM rectifier with the capability of bi-directional current can minimum and eliminate zerocrossing distortion even though there is phase displacement in current loop at the cost of increasing switching loss and larger boost inductor. Then, a simple switched capacitor compensation scheme with low voltage rating switching devices and low switching frequency is presented to minimum zero-crossing distortion. Furthermore, the proposed switched capacitor circuit can be added to existing single-phase PFC converters without modification of original topologies and controllers, hence it is economically feasible. Numerical simulations are given to validate the theoretical analysis and effectiveness of the proposed scheme. With switched capacitor compensator, single-phase PFC converters demonstrate good input performance.

A framework for carrying out train safety evaluation and vibration analysis of a trussed-arch bridge subjected to vessel collision

He Xia,Chaoyi Xia,Nan Zhang,Qin Ma,Xuan Wu 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.59 No.4

Safety is the prime concern for a high-speed railway bridge, especially when it is subjected to a collision. In this paper, an analysis framework for the dynamic responses of train-bridge systems under collision load is established. A multi-body dynamics model is employed to represent the moving vehicle, the modal decomposition method is adopted to describe the bridge structure, and the time history of a collision load is used as the external load on the train-bridge system. A (180+216+180) m continuous steel trussedarch bridge is considered as an illustrative case study. With the vessel collision acting on the pier, the displacements and accelerations at the pier-top and the mid-span of the bridge are calculated when a CRH2 high-speed train running through the bridge, and the influence of bridge vibration on the running safety indices of the train, including derailment factors, offload factors and lateral wheel/rail forces, are analyzed. The results demonstrate that under the vessel collision load, the dynamic responses of the bridge are greatly enlarged, threatening the running safety of high-speed train on the bridge, which is affected by both the collision intensity and the train speed.

Fire Behaviors of Multilayer Latex Foam Coated by Thin Surface Fabric under Bottom Ventilation Conditions

Yiming Shen,Kai Zhang,Dongmei Huang,Chaoyi Wang,Chen Chen,De Li,Long Shi 한국고분자학회 2021 폴리머 Vol.45 No.1

The latex mattress is usually accompanied by fire risk due to its coating material and multi-layer structure. The fire behaviors of multi-layer (with a total thickness of 5 cm) latex foam coated with different fabric layer under bottom ventilation conditions were investigated experimentally. Experimental results showed that fabric coated on the surface of the multi-layer sample could significantly affect the fire behaviors. The combustion duration and peak mass loss rate of single layer sample were obtained 30% shorter and 25% larger than that of the coated samples, respectively. The effects of blending coated from the latex foam surface on the fire behaviors were found larger than those from the cotton coated sample. The total combustion duration and average fuel regression rate of cotton coated samples reduced by 34%, 43.2% when compared to those of the blending coated samples, respectively. With the increase of the number of latex foam layers, the fuel regression rate in the depth direction of the sample increases.

Hydrothermally synthesised NiCoP nanostructures and electrospun N-doped carbon nanofiber as multifunctional potential electrode for hybrid water electrolyser and supercapatteries

Surendran, Subramani,Shanmugapriya, Sathyanarayanan,Zhu, Pei,Yan, Chaoyi,Vignesh, Ramasamy Hari,Lee, Yun Sung,Zhang, Xiangwu,Selvan, Ramakrishnan Kalai Elsevier 2019 ELECTROCHIMICA ACTA Vol.296 No.-

<P><B>Abstract</B></P> <P>In this work, a facile single-step hydrothermal technique is used to prepare a spherically concomitant foamy NiCoP as positrode for supercapatteries. Similarly, the nitrogen-doped carbon nanofibers are prepared by simple electrospinning technique to use as negatrode. The prepared materials are raptly examined through primary studies for both energy conversion and storage applications. Fascinatingly, NiCoP electrode encourages oxygen evolution reaction, and the carbon nanofiber electrode emboldens hydrogen evolution reaction with the minimum overpotential of 257 mV and 160 mV, respectively. In addition, a supercapattery is designed and operated at a full voltage window of 1.6 V using the fusion of carbon nanofiber as the negatrode and the cutting-edge NiCoP as the positrode, which presents a superior energy (56 Wh kg<SUP>−1</SUP>) and an improved power density (5333 W kg<SUP>−1</SUP>) with a long cyclic stability (5000 cycles). Finally, the fabricated supercapattery device is used to power the constructed hybrid water electrolyser that requisites a low cell voltage of 1.71 V to afford a current density of 10 mA cm<SUP>−2</SUP>. Overall, the prepared electrodes reveal its superiority of handling the multifunctional challenges for both water electrolyzer and supercapatteries.</P>

Paridis Saponins Inhibiting Carcinoma Growth and Metastasis In Vitro and In Vivo

Shuli Man,Wenyuan Gao,Yanjun Zhang,Chaoyi Ma,Liu Yang,Yiwen Li 대한약학회 2011 Archives of Pharmacal Research Vol.34 No.1

Paris polyphylla Smith var. yunnanensis extracts, Rhizoma Paridis saponins (RPS) have been found to show strong antitumor activity. However, few studies have yet investigated pulmonary metastasis treatment with this herb. To detail the effective components in RPS and discuss the preliminary mechanism of antitumor effects in vivo and in vitro, a mixture isolated from RPS was investigated. The main constituents were identified as polyphyllin D, formosanin C, dioscin, Paris H, Paris VII and pennogennin 3-O-α-L-rhamnopyranosyl (1→4)-[β-L-rhamnopyranosyl (1→2)]-β-D-glucopyranoside. In our experiments, LA795 cells were exposed to the mixed compounds. Migration inhibition was evaluated by wound healing assay and migration assay in non-cytotoxic dose which was determined by MTT assay. The results demonstrated that the constituent in varying degrees inhibited the migration of the tumor cells in vitro. The mixture also showed antitumor effects on carcinoma in vivo. In conclusion, the mixture is a potent anticancer agent that elicits programmed cell death and inhibits the migration in murine lung adenocarcinoma, both in vitro and in vivo.

Isolation of Dibutyl Phthalate-Degrading Bacteria and Its Coculture with Citrobacter freundii CD-9 to Degrade Fenvalerate

( Min Wu Jie Tang ),( Xuerui Zhou ),( Dan Lei ),( Chaoyi Zeng ),( Hong Ye Ting Cai ),( Qing Zhang ) 한국미생물 · 생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.2

Continued fenvalerate use has caused serious environmental pollution and requires large-scale remediation. Dibutyl phthalate (DBP) was discovered in fenvalerate metabolites degraded by Citrobacter freundii CD-9. Coculturing is an effective method for bioremediation, but few studies have analyzed the degradation pathways and potential mechanisms of cocultures. Here, a DBPdegrading strain (BDBP 071) was isolated from soil contaminated with pyrethroid pesticides (PPs) and identified as Stenotrophomonas acidaminiphila. The optimum conditions for DBP degradation were determined by response surface methodology (RSM) analysis to be 30.9 mg/l DBP concentration, pH 7.5, at a culture temperature of 37.2℃. Under the optimized conditions, approximately 88% of DBP was degraded within 48 h and five metabolites were detected. Coculturing C. freundii CD-9 and S. acidaminiphila BDBP 071 promoted fenvalerate degradation. When CD-9 was cultured for 16 h before adding BDBP 071, the strain inoculation ratio was 5:5 (v/v), fenvalerate concentration was 75.0 mg/l, fenvalerate was degraded to 84.37 ± 1.25%, and DBP level was reduced by 5.21 mg/l. In addition, 12 fenvalerate metabolites were identified and a pathway for fenvalerate degradation by the cocultured strains was proposed. These results provide theoretical data for further exploration of the mechanisms used by this coculture system to degrade fenvalerate and DBP, and also offer a promising method for effective bioremediation of PPs and their related metabolites in polluted environments.