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정붕비(Zheng, Pengfei),태성호(Tae, Sungho),김현식(Kim, Hyunsik),왕역정(Wang, Yijing),조강희(Jo, Kanghee) 대한건축학회 2021 대한건축학회 학술발표대회 논문집 Vol.41 No.2
As the global sustainable development becomes more and more important, the international community pays more attention to the building life cycle assessment. In 2011, the Ministry of Housing and Urban-Rural Development of China presented the building life cycle assessment guidelines called 〈Standard for sustainability assessment of building project〉 as a national standard to guide building life cycle assessment. This paper aims to provide support for the improvement of building life cycle assessment, investigated and analyzed the methods of building life cycle assessment in Standard for sustainability assessment of building project of China. In the end, this paper obtained the process table of the building life cycle assessment guidelines of China.
Near-Five-Vector SVPWM Algorithm for Five-Phase Six-Leg Inverters under Unbalanced Load Conditions
Zheng, Ping,Wang, Pengfei,Sui, Yi,Tong, Chengde,Wu, Fan,Li, Tiecai The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.1
Multiphase machines are characterized by high power density, enhanced fault-tolerant capacity, and low torque pulsation. For a voltage source inverter supplied multiphase machine, the probability of load imbalances becomes greater and unwanted low-order stator voltage harmonics occur. This paper deals with the PWM control of multiphase inverters under unbalanced load conditions and it proposes a novel near-five-vector SVPWM algorithm based on the five-phase six-leg inverter. The proposed algorithm can output symmetrical phase voltages under unbalanced load conditions, which is not possible for the conventional SVPWM algorithms based on the five-phase five-leg inverters. The cause of extra harmonics in the phase voltages is analyzed, and an xy coordinate system orthogonal to the ${\alpha}{\beta}z$ coordinate system is introduced to eliminate low-order harmonics in the output phase voltages. Moreover, the digital implementation of the near-five-vector SVPWM algorithm is discussed, and the optimal approach with reduced complexity and low execution time is elaborated. A comparison of the proposed algorithm and other existing PWM algorithms is provided, and the pros and cons of the proposed algorithm are concluded. Simulation and experimental results are also given. It is shown that the proposed algorithm works well under unbalanced load conditions. However, its maximum modulation index is reduced by 5.15% in the linear modulation region, and its algorithm complexity and memory requirement increase. The basic principle in this paper can be easily extended to other inverters with different phase numbers.
Near-Five-Vector SVPWM Algorithm for Five-Phase Six-Leg Inverters under Unbalanced Load Conditions
Ping Zheng,Pengfei Wang,Yi Sui,Chengde Tong,Fan Wu,Tiecai Li 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.1
Multiphase machines are characterized by high power density, enhanced fault-tolerant capacity, and low torque pulsation. For a voltage source inverter supplied multiphase machine, the probability of load imbalances becomes greater and unwanted low-order stator voltage harmonics occur. This paper deals with the PWM control of multiphase inverters under unbalanced load conditions and it proposes a novel near-five-vector SVPWM algorithm based on the five-phase six-leg inverter. The proposed algorithm can output symmetrical phase voltages under unbalanced load conditions, which is not possible for the conventional SVPWM algorithms based on the five-phase five-leg inverters. The cause of extra harmonics in the phase voltages is analyzed, and an xy coordinate system orthogonal to the ab z coordinate system is introduced to eliminate low-order harmonics in the output phase voltages. Moreover, the digital implementation of the near-five-vector SVPWM algorithm is discussed, and the optimal approach with reduced complexity and low execution time is elaborated. A comparison of the proposed algorithm and other existing PWM algorithms is provided, and the pros and cons of the proposed algorithm are concluded. Simulation and experimental results are also given. It is shown that the proposed algorithm works well under unbalanced load conditions. However, its maximum modulation index is reduced by 5.15% in the linear modulation region, and its algorithm complexity and memory requirement increase. The basic principle in this paper can be easily extended to other inverters with different phase numbers.
Zhang Wentao,Zheng Zongtai,Wang Keyi,Mao Weipu,Li Xue,Wang Guangchun,Zhang Yuanyuan,Huang Jianhua,Zhang Ning,Wu Pengfei,Liu Ji,Zhang Haimin,Che Jianping,Peng Bo,Zheng Junhua,Li Wei,Yao Xudong 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-
Accumulating studies have confirmed that PIWI-interacting RNAs (piRNAs) are considered epigenetic effectors in cancer. We performed piRNA microarray expression analysis on renal cell carcinoma (RCC) tumor tissues and paired normal tissues and performed a series of in vivo and in vitro experiments to explore piRNAs associated with RCC progression and investigate their functional mechanisms. We found that piR-1742 was highly expressed in RCC tumors and that patients with high piR-1742 expression had a poor prognosis. Inhibition of piR-1742 significantly reduced tumor growth in RCC xenograft and organoid models. Mechanistically, piRNA-1742 regulates the stability of USP8 mRNA by binding directly to hnRNPU, which acts as a deubiquitinating enzyme that inhibits the ubiquitination of MUC12 and promotes the development of malignant RCC. Subsequently, nanotherapeutic systems loaded with piRNA-1742 inhibitors were found to effectively inhibit the metastasis and growth of RCC in vivo. Therefore, this study highlights the functional importance of piRNA-related ubiquitination in RCC and demonstrates the development of a related nanotherapeutic system, possibly contributing to the development of therapeutic approaches for RCC.
Le Li,Pengfei Zhu,Qiandong Li,Jianqin Suo,Longxi Zheng 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.4
In order to deeply understand the complex swirling flow characteristics of the typical staged and zoned combustor, particle image velocimetry measurement and large eddy simulation were used to study the steady and instantaneous flow field. The results show that an obviously central recirculation zone (CTRZ) cannot be formed by the single pilot stage swirler. When a main stage swirler with strong swirling flow is added, a large CTRZ appears in the concentric staged dual-swirl combustor. The CTRZ size in the co-rotating combustor is obviously larger than that in the counter-rotating combustor. The development process of the CTRZ is divided into three stages: P, P-M and M. The stages P and M are mainly dominated by the pilot stage and main stage swirling air, respectively. In addition, it can be seen from the instantaneous flow field that there is a single spiral precessing vortex core in the co-rotating and counter-rotating combustor.
A Prefabricated Underground Cylindrical Garage and a Corresponding Stiffness Analysis
Zhenbo Zhang,Pengfei Li,Zheng Li,Mingju Zhang,Haocheng Xiong 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.3
This paper presents a design of a prefabricated structure for an underground cylindrical garage. The performance of this structure and the node connections in terms of lateral stiff ness is investigated, which is critical to the safety of the excavation process. Analytical solutions of the lateral stiff ness of the prefabricated structure are derived considering compatible displacement. A 3D model of the prefabricated structure is developed and used in the numerical simulation to verify the theoretical model. As the key factor of the lateral stiff ness of the prefabricated structure, the lateral stiff ness of the node is also obtained via laboratory testing. Three connection nodes are fabricated according to the design and are tested in the laboratory. The infl uence of the cross-sectional area of the connection beam and the thickness of the column base on the lateral stiff ness of the connection node is also investigated in the laboratory test.
A Virtual RLC Active Damping Method for LCL-Type Grid-Connected Inverters
Yiwen Geng,Yawen Qi,Pengfei Zheng,Fei Guo,Xiang Gao 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.5
Proportional capacitor–current–feedback active damping (AD) is a common damping method for the resonance of LCL-type grid-connected inverters. Proportional capacitor–current–feedback AD behaves as a virtual resistor in parallel with the capacitor. However, the existence of delay in the actual control system causes impedance in the virtual resistor. Impedance is manifested as negative resistance when the resonance frequency exceeds one-sixth of the sampling frequency (fs/6). As a result, the damping effect disappears. To extend the system damping region, this study proposes a virtual resistor–inductor–capacitor (RLC) AD method. The method is implemented by feeding the filter capacitor current passing through a band-pass filter, which functions as a virtual RLC in parallel with the filter capacitor to achieve positive resistance in a wide resonance frequency range. A combination of Nyquist theory and system close-loop pole-zero diagrams is used for damping parameter design to obtain optimal damping parameters. An experiment is performed with a 10 kW grid-connected inverter. The effectiveness of the proposed AD method and the system’s robustness against grid impedance variation are demonstrated.
A Virtual RLC Active Damping Method for LCL-Type Grid-Connected Inverters
Geng, Yiwen,Qi, Yawen,Zheng, Pengfei,Guo, Fei,Gao, Xiang The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.5
Proportional capacitor-current-feedback active damping (AD) is a common damping method for the resonance of LCL-type grid-connected inverters. Proportional capacitor-current-feedback AD behaves as a virtual resistor in parallel with the capacitor. However, the existence of delay in the actual control system causes impedance in the virtual resistor. Impedance is manifested as negative resistance when the resonance frequency exceeds one-sixth of the sampling frequency ($f_s/6$). As a result, the damping effect disappears. To extend the system damping region, this study proposes a virtual resistor-inductor-capacitor (RLC) AD method. The method is implemented by feeding the filter capacitor current passing through a band-pass filter, which functions as a virtual RLC in parallel with the filter capacitor to achieve positive resistance in a wide resonance frequency range. A combination of Nyquist theory and system close-loop pole-zero diagrams is used for damping parameter design to obtain optimal damping parameters. An experiment is performed with a 10 kW grid-connected inverter. The effectiveness of the proposed AD method and the system's robustness against grid impedance variation are demonstrated.