ULTIMATE BEHAVIOR OF PREDATOR-PREY SYSTEM WITH CONSTANT HARVESTING OF THE PREY IMPULSIVELY

Dong, Lingzhen,Chen, Lansun,Sun, Lihua,Jia, Jianwen 한국전산응용수학회 2006 Journal of applied mathematics & informatics Vol.22 No.1

In this paper, we consider the Lotka- Volterra predator-prey system, in which constant quantity of the prey is harvested in regular pulses. The ultimate behavior of the solutions starting from different regions is mainly studied. Further, some examples are given to illustrate our results.

Ultimate behavior of predator-prey system with constant harvesting of the prey impulsively

Lingzhen Dong,Lansun Chen,Lihua Sun,Jianwen Jia 한국전산응용수학회 2006 Journal of applied mathematics & informatics Vol.22 No.1-2

In this paper, we consider the Lotka-Volterra predator-prey system, in which constant quantity of the prey is harvested in regular pulses. The ultimate behavior of the solutions starting from different regions is mainly studied. Further, some examples are given to illustrate our results.

MPC-based Two-stage Rolling Power Dispatch Approach for Wind-integrated Power System

Zhai, Junyi,Zhou, Ming,Dong, Shengxiao,Li, Gengyin,Ren, Jianwen The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.2

Regarding the fact that wind power forecast accuracy is gradually improved as time is approaching, this paper proposes a two-stage rolling dispatch approach based on model predictive control (MPC), which contains an intra-day rolling optimal scheme and a real-time rolling base point tracing scheme. The scheduled output of the intra-day rolling scheme is set as the reference output, and the real-time rolling scheme is based on MPC which includes the leading rolling optimization and lagging feedback correction strategy. On the basis of the latest measured thermal unit output feedback, the closed-loop optimization is formed to correct the power deviation timely, making the unit output smoother, thus reducing the costs of power adjustment and promoting wind power accommodation. We adopt chance constraint to describe forecasts uncertainty. Then for reflecting the increasing prediction precision as well as the power dispatcher's rising expected satisfaction degree with reliable system operation, we set the confidence level of reserve constraints at different timescales as the incremental vector. The expectation of up/down reserve shortage is proposed to assess the adequacy of the upward/downward reserve. The studies executed on the modified IEEE RTS system demonstrate the effectiveness of the proposed approach.

MPC-based Two-stage Rolling Power Dispatch Approach for Wind-integrated Power System

Junyi Zhai,Ming Zhou,Shengxiao Dong,Gengyin Li,Jianwen Ren 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.2

Regarding the fact that wind power forecast accuracy is gradually improved as time is approaching, this paper proposes a two-stage rolling dispatch approach based on model predictive control (MPC), which contains an intra-day rolling optimal scheme and a real-time rolling base point tracing scheme. The scheduled output of the intra-day rolling scheme is set as the reference output, and the real-time rolling scheme is based on MPC which includes the leading rolling optimization and lagging feedback correction strategy. On the basis of the latest measured thermal unit output feedback, the closed-loop optimization is formed to correct the power deviation timely, making the unit output smoother, thus reducing the costs of power adjustment and promoting wind power accommodation. We adopt chance constraint to describe forecasts uncertainty. Then for reflecting the increasing prediction precision as well as the power dispatcher’s rising expected satisfaction degree with reliable system operation, we set the confidence level of reserve constraints at different timescales as the incremental vector. The expectation of up/down reserve shortage is proposed to assess the adequacy of the upward/downward reserve. The studies executed on the modified IEEE RTS system demonstrate the effectiveness of the proposed approach.

Back-channel-etched InGaZnO thin-film transistors with Au nanoparticles on the back channel surface

Peng Xiao,Wenfeng Wang,Yingyi Ye,Ting Dong,Shengjin Yuan,Jiaxing Deng,Li Zhang,Jianwen Chen,Jian Yuan 대한금속·재료학회 2020 ELECTRONIC MATERIALS LETTERS Vol.16 No.2

In this paper, Au nanoparticles (NPs) were introduced on the surface of oxide thin fi lm to enhance the etching resistance of thethin fi lm, and back-channel-etched (BCE) InGaZnO (IGZO) thin fi lm transistors (TFTs) with Au NPs on the back channel surfacewere successfully fabricated. Detailed studies showed that the etching resistance of IGZO thin fi lms was enhanced signifi cantly byintroducing Au NPs on IGZO thin fi lms, and the etching resistance was enhanced with the increase of Au NPs thickness. Furthermore,Au NPs deposited by vaccum evaporation were uniformly dispersed on the IGZO surface other than forming a continuousthin fi lm. By introducing the Au NPs on the IGZO surface, we successfully patterned the S/D electrodes on Au NPs/IGZO andfabricated BCE TFTs. The IGZO-TFTs with 5-nm-thick Au NPs on the back channel surface exhibited excellent electrical characteristicwith a μ sat of 9.9 cm 2 /V s, a SS of 0.26 V/decade, a V on of 0.23 V, an I on/off of 10 6 and an off -state current of 10 −11 A. Inaddition, the introduction of Au NPs did not lead to an increase in the off -state current, which was mainly ascribed to the Schottkybarrier between Au NPs and IGZO due to the high work function of Au. It is a universal method to fabricate BCE TFTs with highelectrical performance, because it was not limited to the types of oxide materials and had no special requirements for equipment.

Coagulation performance of a novel poly-ferric-acetate (PFC) coagulant in phosphate-kaolin synthetic water treatment

Yanxin Wei,Jinpeng Lu,Xiongzi Dong,Jianwen Hao,Chengli Yao 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.10

The process of coagulation-flocculation is increasingly applied in wastewater treatment. And the polymerized inorganic coagulants are widely used among these coagulation-flocculation processes. However, conventional coagulants using sulfates or chlorides as counter anion may give rise to corrosion. The purpose of this study was to synthesize PFC coagulants in which acetate is used as counter anion. The influences on the preparation of PFC were optimized. The synthesis was done at the optimum conditions, such as temperature of 60 oC, the Fe/CH3COOH molar ratio of 1 : 4.0 and reaction time of 6 h, respectively. The prepared PFC coagulants were characterized by Fourier transform infrared (FTIR) spectrophotometry and scanning electron microscopy (SEM). PFC was found to mainly form complexation polymeric species and present more cluster and lamellar structure. A series of jar tests were carried out to study the coagulation performance of PFC and PFS in phosphate-kaolin synthetic water treatment. Results showed that the coagulation performance of PFC was more efficient than PFS’s in terms of the phosphorus removal efficiency and the residual turbidity. Due to using acetate as counter anion to iron, PFC is less harmful to the processes of water treatment and equipment than that of the conventional coagulants applied chlorides or sulfates. Therefore, PFC is a promising coagulant in the process of corrosion sensitive applications and the process of wastewater containing phosphorus treatment.

Periostin (POSTN) Regulates Tumor Resistance to Antiangiogenic Therapy in Glioma Models

Park, Soon Young,Piao, Yuji,Jeong, Kang Jin,Dong, Jianwen,de Groot, John F. American Association for Cancer Research 2016 Molecular cancer therapeutics Vol.15 No.9

<P>Periostin (POSTN) interacts with multiple integrins to coordinate a variety of cellular processes, including epithelial-to-mesenchymal transition (EMT) and cell migration. In our previous study, anti-VEGF-A therapy was associated with resistance and EMT. This study sought to determine the role of POSTN in the resistance of glioma stem cells (GSC) to antiangiogenic therapy. In mouse xenograft models of human glioma, POSTN expression was associated with acquired resistance to anti-VEGF-A therapy and had a synergistic effect with bevacizumab in prolonging survival and decreasing tumor volume. Resistance to anti-VEGF-A therapy regulated by POSTN was associated with increased expression of TGFβ1 and hypoxia-inducible factor-1α (HIF1α) in GSCs. At the molecular level, POSTN regulated invasion and expression of EMT (caveolin-1) and angiogenesis-related genes (<I>HIF1α</I> and <I>VEGF</I>-<I>A</I>) through activation of STAT3. Moreover, recombinant POSTN increased GSC invasion. Collectively, our findings suggest that POSTN plays an important role in glioma invasion and resistance to antiangiogenic therapy. <I>Mol Cancer Ther; 15(9); 2187–97. ©2016 AACR</I>.</P>

Risk Factors for Poor Outcomes Following Minimally Invasive Discectomy: A Post Hoc Subgroup Analysis of 2-Year Follow-up Prospective Data

Zihao Chen,Lei He,Lijun Huang,Zhongyu Liu,Jianwen Dong,Bin Liu,Ruiqiang Chen,Liangming Zhang,Peigen Xie,Limin Rong 대한척추신경외과학회 2022 Neurospine Vol.19 No.1

Objective: A post hoc subgroup analysis of prospectively collected data from a randomized controlled trial was conducted to identify risk factors related to poor outcomes in patients who underwent minimally invasive discectomy. Methods: Patients were divided into satisfied and dissatisfied subgroups based on Oswestry Disability Index (ODI), visual analogue scale (VAS) back pain score (VAS-back) and leg pain score (VAS-leg) at short-term and midterm follow-up according to the patient acceptable symptom state threshold. Demographic characteristics, radiographic parameters, and clinical outcomes between the satisfied and dissatisfied subgroups were compared using univariate and multivariate analysis. Results: A total of 222 patients (92.1%) completed 2-year follow-up, and the postoperative ODI, VAS-back, and VAS-leg were significantly improved after surgery as compared to preoperatively. Multivariate analysis indicated older age (p = 0.026), lateral recess stenosis (p = 0.046), and lower baseline ODI (p = 0.027) were related to poor short-term functional improvement. Higher baseline VAS-back (p = 0.048) was associated with poor short-term relief of back pain, while absence of decreased sensation (p = 0.019) and far-lateral disc herniation (p = 0.004) were associated with poorer short-term relief of leg pain. Lumbar facet joint osteoarthritis was identified as a risk factor for poor functional improvement (p = 0.003) and relief of back pain (p = 0.031). Disc protrusion (p = 0.036) predicted poorer relief of back pain at midterm follow-up. Conclusion: In this study, several factors were identified to be predictive of poor surgical outcomes following minimally invasive discectomy. (ClinicalTrials.gov number: NCT01997086).