Numerical Modelling of the Creep Subsidence of an Ocean Lighthouse Constructed on a Reclaimed Coral Reef Island

Dawei Yu,Jianhong Ye 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.4

This work is to investigate the creep subsidence of a large-scale ocean lighthouse constructed on a reclaimed calcareous coral sand foundation (abbreviated to RCCSF thereafter) in the South China Sea (SCS). Firstly, two modified Burgers creep models, referred to as modified HBM and KBM, respectively, are proposed and validated based on several triaxial creep test results, and then both are implanted into ABAQUS. Secondly, the model parameters of the modified Huang’s Burgers Creep Model (HBM) and Kong’s Burgers Creep Model (KBM) for the RCCSF are carefully calibrated for the subsequent numerical modelling according to the creep tests conducted by us. Thirdly, based on the modified HBM and KBM proposed in this study and the calibrated model parameters, the subsidence of an ocean lighthouse constructed on a reclaimed land in the South China Sea is numerically analyzed. The numerically predicted results illustrate that the creep subsidence of the ocean lighthouse in the future 50-year is 17.2 mm to 42.5 mm, meeting the mandatory requirement (<200 mm) stipulated by the China national design code. Finally, the sensitivity of the predicted creep subsidence to the model parameters is screened by performing parametric analysis.

Management Strategy Based on Genetic Algorithm Optimization for PHEV

Zhang Yu,Meng Dawei,Zhou Meilan,Lu Dengke 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.11

Aiming at the refitted HAFEI hybrid electric vehicle (HEV), fuzzy logic energy management strategy is constructed based on genetic algorithm optimization. The difference value D between the total require torque Tr of path and the target required torque Te of engine, the intelligence quotient value with Tr is selected as the first input variable of fuzzy controller, the SOC of battery as the second input variable; torque control coefficient C is selected as output variable, meanwhile two input variable membership function is improved on genetic algorithm. To further evaluate the control strategy, dynamic programming control strategy is used as standard; the simulation experiments show that every kind of gas emission is obviously reduced by 12% to 47% in fuzzy control strategy B based on genetic algorithm optimization compared to strategy A based on determinacy rules. Compared to dynamic programming, fuel economy in strategy A is only 45.09% of standard value which is not ideal, the utilization of fuel is low and the gas emission is serious, while in strategy B fuel economy is 78.89% of standard value and effect is improved obviously.

Research on Energy Flow Optimization of Compound Storage System in Pure Electric Vehicle with Longitudinal Dynamics

Meng Dawei,Zhang Yu,Zhou Meilan,Tian Xiaochen 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.12

Aiming at short endurance mileage for electric vehicle, effected vehicle life because of battery excessive charging and discharging, the control method is put forward making use of super-capacitor to recovery regenerative braking energy, Hafei-Saibao electric vehicle is as example,seven kinds of topology with composite energy-single load are researched on power consumption, and the force condition of front and rear wheels is analyzed for front driving vehicle,the required energy of front wheel is detected to develop control strategy. On the basis of experimental data, co-simulation is achieved in the vehicle special simulation software, the experimental results show endurance mileage of improved car has increased by 34%, endurance mileage after being charged is 243 kilometer, the per hundred kilometers consumption has been decreased to 7.5 kW.h from 12 kW.h, the electrical consumption has been decreased by 37.5%, and the full load characteristics is optimized.

Facile Self-Assembly of Fe3O4 Nanoparticles@WS2 Nanosheets: A Promising Candidate for Supercapacitor Electrode

Yu Dai,Xiao Wu,Dawei Sha,Ming Chen,Han Zou,Jie Ren,Jingjing Wang,Xuehua Yan 대한금속·재료학회 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.6

Graphene-like dichalcogenides with huge surface area and nanostructuredtransition metal oxides with extraordinarily high theoretical capacities could becomposited as promising electrode candidates for supercapacitors. In this work,monolayer and few-layers WS2 nanosheets were exfoliated by combination ofball-milling and sonication. A facile strategy for the hierarchical self-assembly ofFe3O4 nanoparticles (Fe3O4NPs) on WS2 nanosheets was developed to synthesizeFe3O4NPs@WS2 nanocomposites via hydrothermal method. Fe3O4NPs areuniformly dispersed on the WS2 nanosheets without aggregation. The particlesize of Fe3O4NPs is about 3 nm. The nanocomposite shows strong enhancementsof electrochemical behaviors. This self-assembly synthesis strategy may havegreat prospects for other 0D/2D nanocomposites in supercapacitors and otherenergy devices.

A New Way to Prepare MoO₃/C as Anode of Lithium ion Battery for Enhancing the Electrochemical Performance at Room Temperature

Yu, Zhian,Jiang, Hongying,Gu, Dawei,Li, Jishu,Wang, Lei,Shen, Linjiang The Korean Electrochemical Society 2016 Journal of electrochemical science and technology Vol.7 No.2

Composited molybdenum oxide and amorphous carbon (MoO₃/C) as anode material for lithium ion batteries has been successfully synthesized by calcining polyaniline (PANI) doped with ammonium heptamolybdate tetrahydrate (AMo). The as prepared electrode material was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and field emission scanning electron microscopy (FE-SEM). The electrochemical performance of the anode was investigated by galvanostatic charge/discharge, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The MoO₃/C shows higher specific capacity, better cyclic performance and rate performance than pristine MoO₃ at room temperature. The electrochemical of MoO₃/C properties at various temperatures were also investigated. At elevated temperature, MoO₃/C exhibited higher specific capacity but suffered rapidly declines. While at low temperature, the electrochemical performance was mainly limited by the low kinetics of lithium ion diffusion and the high charge transfer resistance.

A Novel Vertical Handoff Algorithm Based on Differential Pre-Decision and Improved Utility-Function Method

Chenghai Yu,Dawei Ma,Feng Wang,Xiaoan Bao 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.3

The paper proposes a vertical handoff algorithm based on differential pre-decision and improved utility-function method. This algorithm is relied on utility function to improve its two parameters, which are received signal strength and bandwidth, by using their normalized values to determine the target network. Then, it enters judgment stage of vertical handoff, where introduce differential prediction algorithm that has good accuracy to further constraint the switching decision through taking a prediction of the RSS into account. The purpose is to reduce the impact of ping-pong effect and to obtain accurate handoff. The paper applies MATLAB software to gain the simulated analysis based on this algorithm, And compares the performance of this switching algorithm with utility function algorithm to demonstrate its priority. Simulation results shows that the proposed algorithm can significantly reduce the impact of the ping-pong effect and improve the switching efficiency and the system performance as well in heterogeneous network environments.

Radiolabeled polyoxometalate clusters: Kidney dysfunction evaluation and tumor diagnosis by positron emission tomography imaging

Ni, Dalong,Jiang, Dawei,Im, Hyung-Jun,Valdovinos, Hector F.,Yu, Bo,Goel, Shreya,Barnhart, Todd E.,Huang, Peng,Cai, Weibo Elsevier 2018 Biomaterials Vol.171 No.-

<P><B>Abstract</B></P> <P>Radiolabeled nanoprobes for positron emission tomography (PET) imaging has received special attention over the past decade, allowing for sensitive, non-invasive, and quantitative detection of different diseases. The rapidly renal clearable nanomaterials normally suffer from a low accumulation in the tumor through the enhanced permeability and retention (EPR) effect due to the rapidly reduced concentration in the blood circulation after renal clearance. It is highly important to design radiolabeled nanomaterials which can meet the balance between the rapid renal clearance and strong EPR effect within a suitable timescale. Herein, renal clearable polyoxometalate (POM) clusters of ultra-small size (∼1 nm in diameter) were readily radiolabeled with the oxophilic <SUP>89</SUP>Zr to obtain <SUP>89</SUP>Zr-POM clusters, which may allow for efficient staging of kidney dysfunction in a murine model of unilateral ureteral obstruction (UUO). Furthermore, the as-synthesized clusters can accumulate in the tumor through EPR effect and self-assemble into larger nanostructures in the acidic tumor microenvironment for enhanced tumor accumulation, offering an excellent balance between renal clearance and EPR effect.</P> <P><B>Graphical abstract</B></P> <P>Herein, renal clearable polyoxometalate clusters (POM) were readily radiolabeled with the oxophilic <SUP>89</SUP>Zr to allow for efficient staging of kidney dysfunction in a murine model. Furthermore, the as-synthesized clusters can accumulate in the tumor through enhanced permeability and retention (EPR) effect and self-assemble into larger nanostructures in the acidic tumor microenvironment for enhanced tumor accumulation, offering an excellent balance between renal clearance and EPR effect.</P> <P>[DISPLAY OMISSION]</P>

Advice on Standardized Diagnosis and Treatment for Spinal Diseases during the Coronavirus Disease 2019 Pandemic

Jun Zou,Hao Yu,Dawei Song,Junjie Niu,Hui-Lin Yang 대한척추외과학회 2020 Asian Spine Journal Vol.14 No.2

Coronavirus disease 2019 (COVID-19) outbreak started in December 2019 that caused difficulties for clinical work. Practical work experience in our spinal outpatient and emergency department during the COVID-19 pandemic is summarized in this article, with combined evidence-based medical evidence to explore a standardized process of diagnosis and treatment for spinal diseases. Outpatient reservation, continuous screening, triage, and isolation, first consultation accountability system, pandemic reporting system, and online revisit were strictly followed. We hope that our experience in prevention and control of COVID-19 can help spine surgeons globally in stopping the spread of COVID-19. Spine surgeons should collaborate with infection control specialists to avoid cross-infection in hospitals and optimize treatment.

Favorable Impact Toughness of High Heat Input Coarse-Grained HAZ in an Ultra-Low Carbon High-Strength Microalloyed Steel

Fuhui Cui,Junjie Wang1,Xiangdong Gan,Dawei Yu,Ilya Vladimirovich Okulov,Qinghua Tian,Xueyi Guo 대한금속ᆞ재료학회 2023 METALS AND MATERIALS International Vol.29 No.2

Liquid Mg is capable of quickly eroding the refractory Ni-based superalloy and selectively dissolve Ni, which opens up anew avenue for the recycling of superalloy scraps for comprehensive metal reclamation. This study aims at investigating theunderlining mechanism and kinetics of the selective dissolution of Ni from Inconel 718 (one type of Ni-based superalloy)with liquid Mg, by experimenting at 750, 800, and 850 °C for various amounts of time in an inert atmosphere. This selectivedissolution process is also known as liquid metal dealloying. Results show that a permeable dealloyed layer was formedresulting from the preferential dissolution of Ni over other metallic elements (e.g., Fe, Cr, Nb, Mo, and Ti). At the dealloyingforefront, the grain boundaries of the matrix γ phase were preferentially eroded by liquid Mg. The opposite concentrationgradients of Ni (4–9 wt%) and Mg (12–18 wt%) cross the dealloyed layer suggested their counter diffusion. A higher heatingtemperature substantially increased the dealloying rate.

Dealloying Superalloy by Liquid Mg for the Selective Extraction of Ni

Fuhui Cui,Junjie Wang,Xiangdong Gan,Dawei Yu,Ilya Vladimirovich Okulov,Qinghua Tian,Xueyi Guo 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.3

Liquid Mg is capable of quickly eroding the refractory Ni-based superalloy and selectively dissolve Ni, which opens up anew avenue for the recycling of superalloy scraps for comprehensive metal reclamation. This study aims at investigating theunderlining mechanism and kinetics of the selective dissolution of Ni from Inconel 718 (one type of Ni-based superalloy)with liquid Mg, by experimenting at 750, 800, and 850 °C for various amounts of time in an inert atmosphere. This selectivedissolution process is also known as liquid metal dealloying. Results show that a permeable dealloyed layer was formedresulting from the preferential dissolution of Ni over other metallic elements (e.g., Fe, Cr, Nb, Mo, and Ti). At the dealloyingforefront, the grain boundaries of the matrix γ phase were preferentially eroded by liquid Mg. The opposite concentrationgradients of Ni (4–9 wt%) and Mg (12–18 wt%) cross the dealloyed layer suggested their counter diffusion. A higher heatingtemperature substantially increased the dealloying rate.