“I Didn’t Even Know if My Students Were in Class” : Challenges of Teaching English Speaking Online

Qi Qi,Linyu Liao,Cecilia Guanfang Zhao 아시아영어교육학회 2021 The Journal of Asia TEFL Vol.18 No.4

Load-Balanced One-hop Overlay Multipath Routing with Path Diversity

( Jianxin Liao ),( Shengwen Tian ),( Jingyu Wang ),( Tonghong Li ),( Qi Qi ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.2

Overlay routing has emerged as a promising approach to improve reliability and efficiency of the Internet. For one-hop overlay source routing, when a given primary path suffers from the link failure or performance degradation, the source can reroute the traffic to the destination via a strategically placed relay node. However, the over-heavy traffic passing through the same relay node may cause frequent package loss and delay jitter, which can degrade the throughput and utilization of the network. To overcome this problem, we propose a Load-Balanced One-hop Overlay Multipath Routing algorithm (LB-OOMR), in which the traffic is first split at the source edge nodes and then transmitted along multiple one-hop overlay paths. In order to determine an optimal split ratio for the traffic, we formulate the problem as a linear programming (LP) formulation, whose goal is to minimize the worse-case network congestion ratio. Since it is difficult to solve this LP problem in practical time, a heuristic algorithm is introduced to select the relay nodes for constructing the disjoint one-hop overlay paths, which greatly reduces the computational complexity of the LP algorithm. Simulations based on a real ISP network and a synthetic Internet topology show that our proposed algorithm can reduce the network congestion ratio dramatically, and achieve high-quality overlay routing service.

8-60hIPP5^m-Induced G2/M Cell Cycle Arrest Involves Activation of ATM/p53/p21^cip1/waf1 Pathways and Delayed Cyclin B1 Nuclear Translocation

Zeng, Qi-Yan,Zeng, Lin-Jie,Huang, Yu,Huang, Yong-Qi,Zhu, Qi-Fang,Liao, Zhi-Hong Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.9

Protein phosphatase 1 (PP1) is a major serine/threonine phosphatase that controls gene expression and cell cycle progression. The active mutant IPP5 ($8-60hIPP5^m$), the latest member of the inhibitory molecules for PP1, has been shown to inhibit the growth of human cervix carcinoma cells (HeLa). In order to elucidate the underlying mechanisms, the present study assessed overexpression of $8-60hIPP5^m$ in HeLa cells. Flow cytometric and biochemical analyses showed that overexpression of $8-60hIPP5^m$ induced G2/M-phase arrest, which was accompanied by the upregulation of cyclin B1 and phosphorylation of G2/M-phase proteins ATM, p53, $p21^{cip1/waf1}$ and Cdc2, suggesting that $8-60hIPP5^m$ induces G2/M arrest through activation of the ATM/p53/$p21^{cip1/waf1}$/Cdc2/cyclin B1 pathways. We further showed that overexpression of $8-60hIPP5^m$ led to delayed nuclear translocation of cyclin B1. $8-60hIPP5^m$ also could translocate to the nucleus in G2/M phase and interact with $pp1{\alpha}$ and Cdc2 as demonstrated by co-precipitation assay. Taken together, our data demonstrate a novel role for $8-60hIPP5^m$ in regulation of cell cycle in HeLa cells, possibly contributing to the development of new therapeutic strategies for cervix carcinoma.

Evaluate Dry Deposition Velocity of the Nitrogen Oxides Using Noah-MP Physics Ensemble Simulations for the Dinghushan Forest, Southern China

Qi Zhang,Ming Chang,Shengzhen Zhou,Weihua Chen,Xuemei Wang,Wenhui Liao,Jianing Dai,ZhiYong Wu 한국기상학회 2017 Asia-Pacific Journal of Atmospheric Sciences Vol.53 No.4

There has been a rapid growth of reactive nitrogen (Nr) deposition over the world in the past decades. The Pearl River Delta region is one of the areas with high loading of nitrogen deposition. But there are still large uncertainties in the study of dry deposition because of its complex processes of physical chemistry and vegetation physiology. At present, the forest canopy parameterization scheme used in WRF-Chem model is a single-layer “big leaf” model, and the simulation of radiation transmission and energy balance in forest canopy is not detailed and accurate. Noah-MP land surface model (Noah-MP) is based on the Noah land surface model (Noah LSM) and has multiple parametric options to simulate the energy, momentum, and material interactions of the vegetation-soil-atmosphere system. Therefore, to investigate the improvement of the simulation results of WRF-Chem on the nitrogen deposition in forest area after coupled with Noah-MP model and to reduce the influence of meteorological simulation biases on the dry deposition velocity simulation, a dry deposition single-point model coupled by Noah- MP and the WRF-Chem dry deposition module (WDDM) was used to simulate the deposition velocity (Vd). The model was driven by the micro-meteorological observation of the Dinghushan Forest Ecosystem Location Station. And a series of numerical experiments were carried out to identify the key processes influencing the calculation of dry deposition velocity, and the effects of various surface physical and plant physiological processes on dry deposition were discussed. The model captured the observed Vd well, but still underestimated the Vd. The self-defect of Wesely scheme applied by WDDM, and the inaccuracy of built-in parameters in WDDM and input data for Noah-MP (e.g. LAI) were the key factors that cause the underestimation of Vd. Therefore, future work is needed to improve model mechanisms and parameterization.

Study on three-dimensional numerical simulation of shell and tube heat exchanger of the surface ship under marine conditions

Liao Yi,Cai Qi,He Shaopeng,Wang Mingjun,Xiao Hongguang,Gong Zili,Wang Cong,Jia Zhen,Feng Tangtao,Qiu Suizheng 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.4

Shell-and-tube heat exchanger (STHX) is widely used by virtue of its simple structure and high reliability, especially in a space-constrained surface ship. For the STHX of the surface ship, roll, pitch and other motion of the ship will affect the heat transfer performance, resistance characteristics and structural strength of the heat exchanger. Therefore, it is urgent to carry out numerical simulation research on three-dimensional thermal hydraulic characteristics of surface ship STHX under the marine conditions. In this paper, the numerical simulation of marine shell and tube heat exchanger of surface ship was carried out using the porous media model. Firstly, the mathematical physical model and numerical method are validated based on the experimental data of a marine engine cooling water shell and tube heat exchanger. The simulation results are in good agreement with the experimental results. The prediction errors of pressure drop and heat transfer are less than 10% and 1% respectively. The effect of marine conditions on the heat transfer characteristics of the heat exchanger is investigated by introducing the additional force model of marine condition to evaluate the effect of different motion parameters on the heat transfer performance of the heat exchanger. This study could provide a reference for the optimization of marine heat exchanger design.

Experimental investigation of amplitude-dependent self-excited aerodynamic forces on a 5:1 rectangular cylinder

Qi Wang,Bo Wu,Haili Liao,Hanyu Mei 한국풍공학회 2022 Wind and Structures, An International Journal (WAS Vol.34 No.1

This paper presents a study on amplitude-dependent self-excited aerodynamic forces of a 5:1 rectangular cylinder through free vibration wind tunnel test. The sectional model was spring-supported in a single degree of freedom (SDOF) in torsion, and it is found that the amplitude of the free vibration cylinder model was not divergent in the post-flutter stage and was instead of various stable amplitudes varying with the wind speed. The amplitude-dependent aerodynamic damping is determined using Hilbert Transform of response time histories at different wind speeds in a smooth flow. An approach is proposed to extract aerodynamic derivatives as nonlinear functions of the amplitude of torsional motion at various reduced wind speeds. The results show that the magnitude of A2*, which is related to the negative aerodynamic damping, increases with increasing wind speed but decreases with vibration amplitude, and the magnitude of A3* also increases with increasing wind speed but keeps stable with the changing amplitude. The amplitude-dependent aerodynamic derivatives derived from the tests can also be used to estimate the post-flutter response of 5:1 rectangular cylinders with different dynamic parameters via traditional flutter analysis.

Laser direct patterning induced the tunable optical properties of indium tin oxide micro-hole arrays films

Liao Jing,Liu Qingyou,Hong Ruijin,Tao Chunxian,Wang Qi,Lin Hui,Han Zhaoxia,Zhang Dawei 한국물리학회 2022 Current Applied Physics Vol.36 No.-

Here we introduce a facile method to fabricate patterned indium tin oxide (ITO) thin films via selective laser ablation at ambient conditions. By scanning the ITO thin films with focused Nd: YAG pulsed laser, the ITO thin films were selective ablated and patterned without using any conventional chemical etching or photolithography steps. Then we investigated the effects of scanning rate for the structure, morphology and optical properties of patterned ITO thin film. These results indicate that the epsilon-near-zero (ENZ) wavelength of ITO thin films can be tuned from 1100 nm to 1340 nm by adjusting the period of the micro-hole array in microstructure. The nonlinear absorption response of patterned ITO films was about 2.85 time than of the as-deposited ITO thin film. Additionally, the results of the Finite-Difference Time-Domain (FDTD) simulation are in good agreement with those of the experiments.

Dissipative Particle Dynamics Simulation on the Formation Process of CeO₂ Nanoparticles in Alcohol Aqueous Solutions

Zhang, Qi,Zhong, Jing,Yang, Bao-Zhu,Huang, Wei-Qiu,Chen, Ruo-Yu,Liao, Jun-Min,Gu, Chi-Ruei,Chen, Cheng-Lung Korean Chemical Society 2012 대한화학회지 Vol.56 No.4

Dissipative particle dynamics (DPD) was carried out to study the nucleation and crystal growth process of $CeO_2$ nanoparticles in different alcohol aqueous solutions. The results showed that the nucleation and crystal growth process of $CeO_2$ can be classified into three stages: nuclei growth, crystal stabilization and crystal aggregation except the initial induction stage, which could be reproduced by collecting simulation results after different simulation time. Properly selecting the sizes of $CeO_2$ and water bead was crucial in the simulation system. The influence of alcohol type and content in solutions, and precipitation temperature on the particle dimension were investigated in detail and compared with the experimental results. The consistency between simulation results and experimental data verify that the simulation can reproduce the macroscopic particle aggregation process. The effect of solvent on the nucleation and crystal growth of $CeO_2$ nanoparticles are different at three stages and can not be simply described by Derjaguin-Landau-Verwey-Overbeek (DLVO) theory or nucleation thermodynamics theory. Our work demonstrated that DPD methods can be applied to study nanoparticle forming process.

Microwave hydrothermal synthesis and temperature sensing behavior of Lu2Ti2O7:Yb3þ/Er3þ nanophosphors

Jinsheng Liao,Qi Wang,Lifang Lan,Jiangfei Guo,Liling Nie,Suijun Liu,He-Rui Wen 한국물리학회 2017 Current Applied Physics Vol.17 No.3

Lu2Ti2O7:Yb3þ/Er3þ (LTO:Yb3þ/Er3þ) nanophosphors codoped with Yb3þ (8e20 at%) and Er3þ ions (0.5 e4 at%) were synthesized by a microwave hydrothermal process. Under the 980 nm excitation, the sample gives a set of upconversion light: very strong red emissions near 661 nm (4F9/2 / 4I15/2), weak green around 523 nm and 545 nm (2H11/2/4I15/2 and 4S3/2/4I15/2, respectively). The optimum doping concentrations of Er3þ and Yb3þ for the highest emission intensity were determined by photoluminescence (PL) analyses. Concentration dependent studies revealed that the optimal composition was realized for the 12 at% Yb3þ and 2.0 at% Er3þ-doping concentration with a strong emission. A possible UC mechanism for LTO:Yb3þ/Er3þ is discussed via the change of the pump power. The temperature dependence of the fluorescence intensity ratios (FIR) for the two green UC emission bands peaked at 523 and 545 nm was studied in the range of 298e573 K under excitation by a 980 nm diode laser and the maximum sensitivity was approximately 0.00313 K『1 at 536 K. This indicates that LTO:Yb3þ/Er3þ nanophosphors are potential candidates for optical temperature sensors with high sensitivity.

Energy efficiency characteristic analysis of tri‑coil PT symmetric MC‑WPT systems

Zhi-Juan Liao,Qi-Wei Zhu,Wen Ren,Chen-Yang Xia,Xu Liu 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.9

The parity-time (PT) symmetric magnetic coupling wireless power transfer (MC-WPT) system has received a great deal of attention since it was proposed. Its transmission efficiency has been greatly improved when compared with previous research. The operational amplifier (OA) is a typical construction method for PT symmetric MC-WPT systems. On this basis, to achieve a higher transmission efficiency and a longer effective power transmission distance at the same time, this paper constructs an OA-based tri-coil PT symmetric MC-WPT system. The analytical expressions of its singularity, PT symmetric state, and PT symmetric broken state are obtained. Then a complete set of parameter design criteria for the tri-coil PT symmetric system is derived. The transmission efficiency and resonant frequency of two-coil and tri-coil system are simulated on MATLAB software, and the simulation results are consistent with the theoretical analysis results. Finally, an experimental device is constructed to further verify the correctness of the theory. This paper demonstrates that the effective power transmission distance of the tri-coil PT symmetric MC-WPT system is more than twice that of the two-coil PT symmetric MC-WPT system, which can achieve a good balance between transmission efficiency and transmission distance.