A Competition-based Algorithm for Routing Discovery and Repair in Large-scale VANET

( Cheng Wu ),( Lujie Wang ),( Yiming Wang ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.12

Vehicular Ad Hoc Networks (VANET) in the large-scale road section usually have typical characteristics of large number of vehicles and unevenly distribution over geographic spaces. These two inherent characteristics lead to the unsatisfactory performance of VANETs. This poor performance is mainly due to fragile communication link and low dissemination efficiency. We propose a novel routing mechanism to address the issue in the paper, which includes a competition-based routing discovery with priority metrics and a local routing repair strategy. In the routing discovery stage, the algorithm uses adaptive scheme to select a stable route by the priorities of routing metrics, which are the length of each hop, as well as the residual lifetime of each link. Comparisons of different ratios over link length and link stability further show outstanding improvements. In the routing repair process, upstream and downstream nodes also compete for the right to establish repair process and to remain as a member of the active route after repair. Our simulation results confirm the improved performance of the proposed algorithm.

Adsorption differences and mechanism of chitooligosaccharides with specific degree of polymerization on macroporous resins with different functional groups

Yanying Hou,Lujie Liu,Xingxing Zhang,Yuechao Zhu,Yongjun Qiu,Liming Zhao 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.115 No.-

Ion exchange resins are promising materials for separating chitooligosaccharides (COSs) with differentdegrees of polymerization (DP). The adsorbent functional groups significantly determine the interactionswith COSs and affect their adsorption and separation efficiency. This study investigated the adsorptionbehaviors of COSs on macroporous cation exchange resins with different functional groups to clarifythe functional group effect on the adsorption of COSs with different DP, which can also help to providea theoretical basis for the selection of separation medium and optimization of the separation technicsof COSs. The results showed that the adsorption of COSs on sulfonic-acid type resin DX-10 andcarboxylic-acid type resin DC-10 were favorable, and the adsorption isotherms were in accord withthe Sips model. Adsorption thermodynamics showed that temperature had opposite effects on the tworesins’ equilibrium adsorption capacity of COSs. The diffusion coefficient of COSs on DX-10 resin wasgreater, and the affinity gap between COSs on DX-10 resin was larger than that of DC-10 resin, whichis beneficial for improving the separation resolution of COSs. In contrast, the interaction energy betweenCOSs with high DP and DC-10 resin was weaker compared with DX-10, which made the elution of COSswith high DP easier.

Adsorptive removal of Cr(VI) from aqueous solutions by cross-linked chitosan/bentonite composite

Qian Liu,Bingchao Yang,Lujie Zhang,Ruihua Huang 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.7

Cross-linked chitosan/bentonite composite (CCB) was prepared, and characterized by Fourier transform infrared (FTIR) spectroscopy, BET surface area and pore diameter analyses, X-ray diffraction (XRD) patterns and thermal gravimetric analyses (TGA). The adsorption of hexavalent chromium Cr(VI) onto CCB as a function of adsorbent dosage, initial Cr(VI) concentration, solution pH, and contact time was investigated through batch experiments. The removal towards Cr(VI) decreased with increasing solution pH from 2 to 11 and initial Cr(VI) concentration, while it increased with increasing adsorbent dosage. The adsorption kinetic data of Cr(VI) on CCB were well described by the pseudo-second-order model. The equilibrium data were correlated by the Langmuir isotherm model. The maximum monolayer Cr(VI) adsorption capacity for CCB at pH 2 and 293 K was 89.13mg/g. The mechanisms for the adsorption of Cr(VI) on CCB at pH 2 may include electrostatic interaction and chemical interaction between CCB and Cr(VI) ions.

Half-Cycle-Waveform-Inversed Single-Carrier Seven-level Sinusoidal Modulation

Fengjiang Wu,Bo Sun,Lujie Zhang,Li Sun 전력전자학회 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.1

A half-cycle-waveform inversion based three reference modulations seven-level SPWM (TRM-SPWM) scheme with one carrier is proposed in this paper. To keep the same comparison logics for the modulations and carrier during the negative half cycle and the positive one for the modulations, in the negative half cycle of the modulations, the DC offsets related to the amplitude of the carrier are set on the three modulations, respectively. The seven-level SPWM waveform with dead time thereby is implemented with only one Digital Signal Processor (DSP) without any other attached logic circuit. The basis principle of the proposed TRM-SPWM is analyzed in detail, and the frequency spectrums of the conventional and the proposed schemes are derived and compared with each other through simulation. The DSP based implementation is presented and detailed experimental waveforms verify the accuracy and feasibility of the proposed TRM-SPWM scheme.

Simultaneous adsorption of phenol and Cu2+ from aqueous solution by activated carbon/chitosan composit

Qian Liu,Bingchao Yang,Lujie Zhang,Ruihua Huang 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.9

A multifunction adsorbent was synthesized by incorporating AC into CTS, and the ratio of AC to CTSwas 1/1. The resultant was called activated carbon (AC)/chitosan (CTS) composite. The simultaneous adsorption ofphenol and Cu2+from aqueous solution onto AC/CTS composite was investigated by a batch procedure. The adsorptionprocesses for both Cu2+and phenol obeyed the pseudo second-order kinetic model. Phenol was prone to be adsorbedmore quickly as compared with Cu2+when they coexisted in solution. The adsorption behavior of both phenol and Cu2+followed the Langmuir isotherm. The maximum adsorption capacities of phenol and Cu2+were 34.19 mg/g and 74.35mg/g at 293 K, respectively. No obvious competitive adsorption existed between phenol and Cu2+.

Half-Cycle-Waveform-Inversed Single-Carrier Seven-level Sinusoidal Modulation

Wu, Fengjiang,Sun, Bo,Zhang, Lujie,Sun, Li The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.1

A half-cycle-waveform inversion based three reference modulations seven-level SPWM (TRM-SPWM) scheme with one carrier is proposed in this paper. To keep the same comparison logics for the modulations and carrier during the negative half cycle and the positive one for the modulations, in the negative half cycle of the modulations, the DC offsets related to the amplitude of the carrier are set on the three modulations, respectively. The seven-level SPWM waveform with dead time thereby is implemented with only one Digital Signal Processor (DSP) without any other attached logic circuit. The basis principle of the proposed TRM-SPWM is analyzed in detail, and the frequency spectrums of the conventional and the proposed schemes are derived and compared with each other through simulation. The DSP based implementation is presented and detailed experimental waveforms verify the accuracy and feasibility of the proposed TRM-SPWM scheme.

Stochastic Optimization of Multipath TCP for Energy Minimization and Network Stability over Heterogeneous Wireless Network

( Zulfiqar A. Arain ),( Xuesong Qiu ),( Lujie Zhong ),( Mu Wang ),( Xingyan Chen ),( Yongping Xiong ),( Kiran Nahida ),( Changqiao Xu ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.1

Multipath Transport Control Protocol (MPTCP) is a transport layer protocol that enables multiple TCP connections across various paths. Due to path heterogeneity, it incurs more energy in a multipath wireless network. Recent work presents a set of approaches described in the literature to support systems for energy consumption in terms of their performance, objectives and address issues based on their design goals. The existing solutions mainly focused on the primary system model but did not discourse the overall system performance. Therefore, this paper capitalized a novel stochastically multipath scheduling scheme for data and path capacity variations. The scheduling problem formulated over MPTCP as a stochastic optimization, whose objective is to maximize the average throughput, avoid network congestion, and makes the system more stable with greater energy efficiency. To design an online algorithm that solves the formulated problem over the time slots by considering its min-drift-plus penalty form. The proposed solution was examined under extensive simulations to evaluate the anticipated stochastic optimized MPTCP (so-MPTCP) outcome and compared it with the base MPTCP and the energy-efficient MPTCP (eMPTCP) protocols. Simulation results justify the proposed algorithm's credibility by achieving remarkable improvements, higher throughput, reduced energy costs, and lower-end to end delay.

Enhanced Photoelectrochemical Water Splitting and Photocatalytic Water Oxidation of Cu2O Nanocube-Loaded BiVO4 Nanocrystal Heterostructures

Wenzhong Wang,Weiwei Zhang,Shan Meng,Lujie Jia,Miao Tan,Chenchun Hao,Yujie Liang,JUN WANG,Bin Zou 대한금속·재료학회 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.6

Reducing the fast recombination of photogenerated electron-hole pairsof semiconductor photocatalyst is very important to improve itsphotocatalysis. In this paper we fabricate Cu2O nanocube-decoratedBiVO4 nanocrystal (denoted as BiVO4@Cu2O nanocrystal@nanocube)heterostructure photocatalyst by coupling n-type BiVO4 with p-type Cu2O. The BiVO4@Cu2O nanocrystal@nanocube photocatalysts show superiorphotocatalytic activities in photoelectrochemical (PEC) activity andphotocatalytic water oxidation to BiVO4 photocatalysts under visible lightillumination. The BiVO4@Cu2O nanocrystal@nanocube heterostructureelectrode achieves the highest photocurrent density of ~ 10 μA cm−2 at 0 Vversus Ag/AgCl, 5 times higher than that of BiVO4 nanocrystal electrode (~ 2 μA cm−2). The light induced evolution rate of O2generation for BiVO4@Cu2O nanocrystal@nanocube heterostructures is as high as 150 μmol h−1100 mg cat−1, more than 3times higher than that (48 μmol h−1100 mg cat−1) of BiVO4 nanocrystals. The enhanced photocatalysis activities of theBiVO4@Cu2O nanocrystal@nanocube photocatalysts are attributed to the efficient separation of the photoexcited electron-holepairs caused by inner electronic field (IEF) of p-n junction. This study opens up new opportunities in designing photoactivematerials with highly enhanced performance for solar energy conversion.

High-mobility three-atom-thick semiconducting films with wafer-scale homogeneity

Kang, Kibum,Xie, Saien,Huang, Lujie,Han, Yimo,Huang, Pinshane Y.,Mak, Kin Fai,Kim, Cheol-Joo,Muller, David,Park, Jiwoong Nature Publishing Group, a division of Macmillan P 2015 Nature Vol.520 No.7549

The large-scale growth of semiconducting thin films forms the basis of modern electronics and optoelectronics. A decrease in film thickness to the ultimate limit of the atomic, sub-nanometre length scale, a difficult limit for traditional semiconductors (such as Si and GaAs), would bring wide benefits for applications in ultrathin and flexible electronics, photovoltaics and display technology. For this, transition-metal dichalcogenides (TMDs), which can form stable three-atom-thick monolayers, provide ideal semiconducting materials with high electrical carrier mobility, and their large-scale growth on insulating substrates would enable the batch fabrication of atomically thin high-performance transistors and photodetectors on a technologically relevant scale without film transfer. In addition, their unique electronic band structures provide novel ways of enhancing the functionalities of such devices, including the large excitonic effect, bandgap modulation, indirect-to-direct bandgap transition, piezoelectricity and valleytronics. However, the large-scale growth of monolayer TMD films with spatial homogeneity and high electrical performance remains an unsolved challenge. Here we report the preparation of high-mobility 4-inch wafer-scale films of monolayer molybdenum disulphide (MoS<SUB>2</SUB>) and tungsten disulphide, grown directly on insulating SiO<SUB>2</SUB> substrates, with excellent spatial homogeneity over the entire films. They are grown with a newly developed, metal–organic chemical vapour deposition technique, and show high electrical performance, including an electron mobility of 30 cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> at room temperature and 114 cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> at 90 K for MoS<SUB>2</SUB>, with little dependence on position or channel length. With the use of these films we successfully demonstrate the wafer-scale batch fabrication of high-performance monolayer MoS<SUB>2</SUB> field-effect transistors with a 99% device yield and the multi-level fabrication of vertically stacked transistor devices for three-dimensional circuitry. Our work is a step towards the realization of atomically thin integrated circuitry.

Enhanced metabolic flux of methylerythritol phosphate (MEP) pathway by overexpression of Ginkgo biloba 1‑Hydroxy‑2‑methyl‑2‑(E)‑butenyl 4‑diphosphate Reductase 1 (GbHDR1) gene in poplar

Kang Min-Kyoung,Kim Ji-Young,Choi Young-Im,Hu Lujie,Yang Chaodong,Jin Zhehao,Park Yun Ji,Kim Soo-Un,Kim Sang-Min 한국응용생명화학회 2022 Applied Biological Chemistry (Appl Biol Chem) Vol.65 No.4

Terpenoids are of great interests in a broad range of health-beneficial biological activities and various industrial applications. In plants, terpenoids are synthesized by two distinct pathways, methylerythritol phosphate (MEP) and mevalonate pathways in a separate location. MEP pathway supplies isoprene precursors isopentenyl diphosphate (IPP) and its isomer dimethylallyl diphosphate (DMAPP) of terpenoid biosynthesis in plant plastids. The MEP pathway has been an engineering target to increase the metabolic flux towards higher terpenoid production in plants. 1-Hydroxy-2-methyl-2-( E )-butenyl-4-diphosphate reductase (HDR) is the terminal step of the MEP pathway to regulate the terpenoid biosynthesis and is encoded by three paralogous genes in Ginkgo biloba. In this study, we assessed the effect of overexpression of GbHDR1 on terpenoid metabolism in poplar plants. Overexpression of GbHDR1 in poplar plants accelerated growth and delayed winter-bud formation. Transcript levels of gibberellin, chlorophylls, and carotenoid biosynthetic genes in GbHDR1- overexpressing ( GbHDR1 ox) poplars were up-regulated, suggesting metabolic flux enhancement. Moreover, enhanced contents of chlorophylls and carotenoids in the leaves of the GbHDR1 ox plants resulted in a higher photosynthetic rate as a consequence. Therefore, we expect the GbHDR1 overexpression will be a desirable engineering point of the MEP pathway for enhancing terpenoid metabolic flux and production in plants.