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Yongpeng Ma,Dongli Yuan,Xiaojing Zhang,Zan Qu,Wenjun Huang 대한환경공학회 2021 Environmental Engineering Research Vol.26 No.2
In this work, we investigated the absorption characteristics of SO₂ and the effect of inhibitors on the desulfurization performances of Na₂SO₃. The results showed that the NO₂ had a competitive effect with SO₂ on SO₃<SUP>2-</SUP> which resulted in a significant decrease in the absorption capacity of SO₂. O₂ in the flue gas could decrease the absorption capacity of SO₂ due to the oxidation of Na₂SO₃. Besides, Na₂S₂O₃ had more excellent inhibiting effect on the oxidation of SO₃<SUP>2-</SUP>; the inhibition mechanism is understood on the basis of the free radical chain reaction, whereby S₂O₃<SUP>2-</SUP> combined with the sulfite free radical to form an inert substance, thus, quenching the reaction of free radical with the dissolved oxygen and invariably inhibiting the oxidation of SO₃<SUP>2-</SUP>. Furthermore, the intrinsic and the apparent oxidation kinetics of Na₂SO₃ oxidation process with Na₂S₂O₃ were investigated to explain the relationships between consumption rates of SO₃<SUP>2-</SUP> and the absorption capacities of SO₂ under different components in flue gas and absorption solution.
Yongpeng Chen,Xin Liu,Xiao Yang,Yong Yang 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.5
High-speed dry hobbing is a desirable green machining process for cylindrical gears, and is further expected to be used for gear finishing so as to acquire higher productivity and lower cost. However, the generated gear tooth surface by hobbing is associated with a unique textured morphology which would affect its performance. Based on the principle of gearing, this paper proposes an accurate mathematical model for simulating the generated tooth surface morphology appropriated for both high-speed dry hobbing and conventional hobbing. The model is verified by comparing the simulation result with a high-speed dry gear hobbing experiment. With the proposed model, comparison between high-speed dry hobbing and conventional hobbing is put forward on the difference in generated tooth surface morphology resulted from the utilized process parameter and hob geometry. In addition, the influence of employed process parameter and geometry of hob on the tooth surface morphology in high-speed dry hobbing is investigated and discussed. The proposed model can be applied for process analysis and parameters selection of high-speed dry hobbing for finishing gears.
Yongpeng Shi,Junjie Zhang,Ya Gao,Yujie Xia 한국통신학회 2022 Journal of communications and networks Vol.24 No.3
Combining mobile edge computing (MEC), themulti-drone aided space-air-ground integrated Internet of things(SAG-IoT) networks can provide ground IoT devices (GIDs) highqualitywireless access and computing services. However, the diversetasks, moving drones, and limited network resources revealgreat challenges for the task offloading and resource allocationscheme exploitation. Especially, given the restricted computationresources, how to make full use of available applications deployedon MEC servers (MECSs) to compute various types of tasks, iseven an important issue. To the best of our knowledge, it is anentirely new problem since most existing works in this line assumethat all types of applications can be deployed on one MECS so asto process various offloaded tasks. Toward this end, we presentthis paper to investigate inter-server computation offloading, resourceallocation, and drone deployment to minimize the overallcomputation overhead of all GIDs. An iteratively optimizationalgorithm is proposed which alternately utilizes heuristic greedyand successive convex approximation methods. Simulation resultsverify that, for different GID numbers, optimization schemes, andcomputing models, our devised schemes can not only significantlyreduce the overall computation overhead but also achieve optimaldecisions of computation offloading, spectrum allocation, anddrone deployment.
( Yongpeng Shi ),( Yujie Xia ),( Ya Gao ),( Jianhua Cui ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.8
The tone reservation (TR) scheme is an attractive method to reduce peak-to-average power ratio (PAPR) in the filter bank multicarrier with offset quadrature amplitude modulation (FBMC-OQAM) systems. However, the high PAPR of FBMC signal will severely degrades system performance. To address this issue, a cyclic shift based TR (CS-TR) scheme with embedding side information (SI) is proposed to reduce the PAPR of FBMC signals. At the transmitter, four candidate signals are first generated based on cyclic shift of the output of inverse discrete Fourier transform (IDFT), and the SI of the selected signal with minimum peak power among the four candidate signals is embedded in sparse symbols with quadrature phase-shift keying constellation. Then, the TR weighted by optimal scaling factor is employed to further reduce PAPR of the selected signal. At the receiver, a reliable SI detector is presented by determining the phase rotation of SI embedding symbols, and the transmitted data blocks can be correctly demodulated according to the detected SI. Simulation results show that the proposed scheme significantly outperforms the existing TR schemes in both PAPR reduction and bit error rate (BER) performances. In addition, the proposed scheme with detected SI can achieve the same BER performance compared to the one with perfect SI.
Wang Yongpeng,Wang Heng,Zhang Qingwen,Zhang Yingyuan,Yan Pengtao,Liu Mengzhu,Zhang Haibo 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.8
Multi-walked carbon nanotube (MWCNT)/poly(aryl ether ketone) networks cross-linked by Diels-Alder cycloaddition possess outstanding mechanical and rheological properties. Poly(aryl ether ketone) containing pendant furan (PAEK-Fu) was synthesized, which had excellent thermal and mechanical properties, and a series of cross-linked materials with reversible covalent cross-linked crosslinking network were synthesized through a furan/MWCNTs Diels-Alder (D-A) reaction between PAEK-Fu and MWCNTs. Thermal and mechanical properties for MWCNT/PAEK-Fu composites were studied, and after crosslinking, MWCNT/PAEK-Fu composites exhibited good flexibility and resistance against organic solvents. After heating to 180 °C, the cross-linked MWCNT/PAEK-Fu composite membranes could be dissolved in NMP. This work demonstrates that the poly(aryl ether ketone)s can be made into recyclable thermoset materials using the concept of associative dynamic bonding. Given the dramatically increasing interest in environmentally sustainable materials, this MWCNT/poly(aryl ether ketone) interaction mode provides a robust approach to high performance engineering plastics with improved performance compared with the thermoplastic counterparts.
Energy Management Strategy for Hybrid Energy Storage System based on Model Predictive Control
Shen Yongpeng,Li Yuanfeng,Liu Dongqi,Wang Yanfeng,Sun Jianbin,Sun Songnan 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.4
Electric vehicle (EV) is developed because of its environmental friendliness, energy-saving and high efficiency. For improving the performance of the energy storage system of EV, this paper proposes an energy management strategy (EMS) based model predictive control (MPC) for the battery/supercapacitor hybrid energy storage system (HESS), which takes stabilizing the DC bus voltage and improving the efficiency of the system as two major optimization goals. In addition, an enumeration algorithm is presented to solve the optimization function. The experimental results show the performance of the proposed EMS which is able to enhance the overall instantaneous power and prevent the battery from overloading. Meanwhile, compared with the results of a single battery storage system, the maximum amplitude of the battery current in the HESS is reduced by 40.81% and whole system energy loss is reduced by 24.13% with the proposed power management strategy.
Dong, Yongpeng,Fan, Shengjun Korean Mathematical Society 2018 대한수학회논문집 Vol.33 No.3
This paper is devoted to the existence and uniqueness of $L^p$ (p > 1) solutions for general time interval multidimensional backward stochastic differential equations (BSDEs for short), where the generator g satisfies a ($p{\wedge}2$)-order weak monotonicity condition in y and a Lipschitz continuity condition in z, both non-uniformly in t. The corresponding stability theorem and comparison theorem are also proved.
Qi Shi,Yongpeng Lei,Yingde Wang,Huaping Wang,Lehua Jiang,Hongliang Yuan,Dong Fang,Bing Wang,Nan Wu,Yanzi Gou 한국물리학회 2015 Current Applied Physics Vol.15 No.12
B, N-codoped carbon nanofibers were massively prepared by heat treatment of electrospun carbon nanofibers with the mixture of boric acid/urea in N2 (BNCf-N) and subsequently activated in NH3 (BNCf- NA). The directly electrospun self-standing 3D non woven structure with void spaces between each fiber facilitates the mass transport of reactant and resulted molecules. Further NH3 activation gives BNCf-NA a high surface area of 306.3 m2 g-1 with micro/mesoporous structure, providing abundant passageway for proton transfer. Simultaneously, NH3 activation also realizes the optimization of surface functionalities, such as more BeNeC and pyridinic-N. These intriguing features render BNCf-NA excellent catalytic behavior with nearly four-electron oxygen reduction reaction (ORR) process in alkaline media, especially much better stability and methanol tolerance than the commercial Pt/C catalyst. Our work provides a large-scale preparation method for efficient metal-free catalysts toward ORR, thus further intensifying the commercial application of fuel cells.
Performance Optimization and Analysis on P2P Mobile Communication Systems Accelerated by MEC Servers
( Xuesong Liang ),( Yongpeng Wu ),( Yujin Huang ),( Derrick Wing Kwan Ng ),( Pei Li ),( Yingbiao Yao ) 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.1
As a promising technique to support tremendous numbers of Internet of Things devices and a variety of applications efficiently, mobile edge computing (MEC) has attracted extensive studies recently. In this paper, we consider a MEC-assisted peer-to-peer (P2P) mobile communication system where MEC servers are deployed at access points to accelerate the communication process between mobile terminals. To capture the tradeoff between the time delay and the energy consumption of the system, a cost function is introduced to facilitate the optimization of the computation and communication resources. The formulated optimization problem is non-convex and is tackled by an iterative block coordinate descent algorithm that decouples the original optimization problem into two subproblems and alternately optimizes the computation and communication resources. Moreover, the MEC-assisted P2P communication system is compared with the conventional P2P communication system, then a condition is provided in closed-form expression when the MEC-assisted P2P communication system performs better. Simulation results show that the advantage of this system is enhanced when the computing capability of the receiver increases whereas it is reduced when the computing capability of the transmitter increases. In addition, the performance of this system is significantly improved when the signal-to-noise ratio of hop-1 exceeds that of hop-2.