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Research on New Energy Power Grid-Integration on Grid Power Quality
Aijun Zhang,Xingfeng Xiao,Xuan Fu,Dan Wang 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.4
Distribution network is an important part of the power system which delivers the electric power to consumers. With the increasing attention to the new energy power generation, more and more distributed photovoltaic power systems are connected to the distribution network. In this paper, it researches on new energy power grid-integration on grid power quality. First, the technologies of wind and solar power are introduced. Second, the concepts of power quality and evaluation index are introduced. Finally, voltage deviations and harmonics are mainly elaborated.
Zhen Zhang,Hui Hua Huang,Xiang Ma,Guanghui Li,Yong Wang,Guo Sun,Yinglai Teng,Rian Yan,Ning Zhang,AiJun Li 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.53 No.-
A new and efficient technique is described for the production of diacylglycerols (DAGs) by the esterification of oleic acid with glycerol catalyzed by diatomite-loaded SO4 2/TiO2. DAGs show some potential health benefits compared to triacylglycerols, and also can be used to produce the novel industrial plasticizer epoxy fatty acid methyl ester in material science. Diatomite-loaded SO4 2/TiO2 catalyst was prepared and characterized, and the selected conditions for the synthesis of DAGs were determined to be: reaction time = 6.0 h, temperature = 210 C, catalyst loading = 0.1% of the oleic acid weight, and mass ratio of oleic acid to glycerol = 2:1. Under these conditions, DAGs yield reached 59.6% with a purity of 69.6% after a one-stage molecular distillation. Diatomite-loaded SO4 2/TiO2 as a solid catalyst could be recycled and reused with high catalytic efficiency. Under the same conditions, diatomite-loaded SO4 2/TiO2 showed a better catalytic performance than the commercial solid acid SO4 2/ZrO2-Al2O3. Based on this, a two-step reaction method for the production of DAGs was performed and provided a yield similar to the one-step method (58.3% vs. 59.6%), but with a shorter reaction time (4 h vs. 6 h). It is concluded that a two-step reaction method could be a better alternative to the one-step production of DAGs in the presence of diatomite-loaded SO4 2/TiO2.
Rong Jiang,Jianqing Zhu,김재원,Jihong Liu,Kazuyoshi Kato,김희승,Yuqin Zhang,Ping Zhang,Tao Zhu,Daisuke Aoki,Aijun Yu,Xiaojun Chen,Xipeng Wang,Ding Zhu,Wei Zhang,Huixun Jia,Ting-Yan Shi,Wen Gao,Sheng Yin,Yan 대한부인종양학회 2020 Journal of Gynecologic Oncology Vol.31 No.5
Background: Two randomized phase III trials (EORTC55971 and CHORUS) showed similarprogression-free and overall survival in primary or interval debulking surgery in ovariancancer, however both studies had limitations with lower rate of complete resection and lack ofsurgical qualifications for participating centers. There is no consensus on whether neoadjuvantchemotherapy followed by interval debulking surgery (NACT-IDS) could be a preferred approachin the management of advanced epithelial ovarian cancer (EOC) in the clinical practice. Methods: The Asian SUNNY study is an open-label, multicenter, randomized controlled,phase III trial to compare the effect of primary debulking surgery (PDS) to NACT-IDS instages IIIC and IV EOC, fallopian tube cancer (FTC) or primary peritoneal carcinoma (PPC). The hypothesis is that PDS enhances the survivorship when compared with NACT-IDS inadvanced ovarian cancer. The primary objective is to clarify the role of PDS and NACT-IDS inthe treatment of advanced ovarian cancer. Surgical quality assures include at least 50% of nogross residual (NGR) in PDS group in all centers and participating centers should be nationalcancer centers or designed ovarian cancer section or those with the experience participatingsurgical trials of ovarian cancer. Any participating center should be monitored evaluatingthe proportions of NGR by a training set. The aim of the surgery in both arms is maximalcytoreduction. Tumor burden of the disease is evaluated by diagnostic laparoscopy orpositron emission tomography/computed tomography scan. Patients assigned to PDS groupwill undergo upfront maximal cytoreductive surgery within 3 weeks after biopsy, followed by6 cycles of standard adjuvant chemotherapy. Patients assigned to NACT group will undergo 3cycles of NACT-IDS, and subsequently 3 cycles of adjuvant chemotherapy. The maximal timeinterval between IDS and the initiation of adjuvant chemotherapy is 8 weeks. Major inclusioncriteria are pathologic confirmed stage IIIC and IV EOC, FTC or PPC; ECOG performancestatus of 0 to 2; ASA score of 1 to 2. Major exclusion criteria are non-epithelial tumors as wellas borderline tumors; low-grade carcinoma; mucinous ovarian cancer. The sample size is 456subjects. Primary endpoint is overall survival. Trial Registration: ClinicalTrials.gov Identifier: NCT02859038
Zhang, Zhenguo,Yang, Aijun,Di, Congna 한국전산응용수학회 2007 Journal of applied mathematics & informatics Vol.25 No.1
In this paper, the existence of bounded positive solution of the second-order nonlinear neutral differential equations are studied. Some new sufficient conditions are given. Furthermore, examples given show that the results here are almost sharp.
A Secure MQAM Scheme Based on Signal Constellation Hopping
( Yingxian Zhang ),( Aijun Liu ),( Xiaofei Pan ),( Zhan Ye ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.7
In this paper, a secure multilevel quadrature amplitude modulation (MQAM) scheme is proposed for the physical layer security (PLS) of the wireless communications. In the proposed scheme, each transmitted symbol`s signal constellation (SC) is hopping with the control of two unique factors: amplitude distortion (AD) factor and phase hopping (PH) factor. With unknown the two factors, the eavesdropper cannot extract effective information from the received signal. We first introduce a security metric, referred to as secrecy gain, and drive a lower bound on the gain that the secrecy capacity can be improved. Then, we investigate the relationship among the secrecy gain, the signal to noise power ratios (SNRs) of the main and wiretap channels, and the secrecy capacity. Next, we analyze the security of the proposed scheme, and the results indicate that the secrecy capacity is improved by our scheme. Specifically, a positive secrecy capacity is always obtained, whether the quality of the main channel is better than that of the wiretap channel or not. Finally, the numerical results are provided to prove the analytical work, which further suggests the security of the proposed scheme..
OSCILLATION AND NONOSCILLATION OF HIGHER-ORDER DIFFERENCE EQUATIONS WITH NONLINEAR NEUTRAL TERMS
Zhenguo Zhang,Aijun Yang,Congna Di 한국수학교육학회 2007 純粹 및 應用數學 Vol.14 No.2
In this paper, the oscilation and existence of nonoscilatory solutions of odd order difference equations with nonlinear neutral terms are studied respec-tively. Some new criteria are established. Furthermore, some examples are given to illustrate the advance of our results.
Research on Operation and Control of Micro-Grid System
Cunxu Wang,Xingfeng Xiao,Aijun Zhang,Xiaoyu Sun 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.7
Micro-grid is the significant part of the distribution network in the future of smart grid, which has advanced and flexible operation and control pattern, and integrates distributed clean energy. It is a study of the direction of the grid in the future. In the paper, it gives an account of the operation and control of micro-grid. First, the concept of micro-grid, the structure and characteristics of the typical micro-grid and the significance of the development of micro-grid are analyzed. Second, it introduces typical control strategy which contains the integrated control strategy of Micro-grid and a typical control mode of Micro-power. At last, based on a comprehensive control strategy, it proposed the operation mode of Micro-grid.
Yanbin Li,Heng Jia,Aijun Zhang,Bing Xiao,Yongsheng Zhu,Tingting Wei 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.6
This paper presents a multi-objective robust optimization method for a drive system consisting of a permanent magnet transverse flux machine with soft magnetic composite cores and a field-oriented controller. Unlike existing research work, the torque ripple is considered an optimization objective. Several machine uncertainties caused by manufacturing tolerances are investigated in the robust optimization model under the framework of the design for six-sigma. Since this is a system-level optimization problem, two approximation models are employed to decrease the computational cost. First, a Kriging model is used to approximate the steady-state electromagnetic performances of the motor, such as the output power and efficiency. Second, a Taylor series approximation is employed to estimate the dynamic performances of the control system, such as the speed overshoot and settling time. Furthermore, a sampling selection method is proposed to reduce the computational cost of the Monte Carlo analysis in robust optimization. To show the eff ectiveness of the proposed method, both deterministic and robust Pareto solutions are presented and discussed. It can be seen that the system-level multi-objective design optimization based on robust approach can produce optimal Pareto solutions with a high manufacturing quality for the whole drive system. This is valuable for the batch production of electrical drive systems.