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Nian Cheng,Weiwei Li,Menghan Zhang,Hangjuan Wu,Shujie Sun,Zhiqiang Zhao,Zhenyu Xiao,Zhuzhu Sun,Wei Zi,Liang Fang 한국물리학회 2019 Current Applied Physics Vol.19 No.1
Employing additive to regulate the morphology of perovskite film is an effective method to enhance both the power conversion efficiency and long term stability of organic-inorganic hybrid perovskite solar cells. Here, we demonstrate that guanidinium thiocyanate (GuSCN) is a suitable additive for methylammonium lead iodide (MAPbI3) perovskite materials. Addition of GuSCN into MAPbI3 can simultaneously enhance the crystallinity, enlarge the crystal size, and reduce the trap density of the perovskite films. As a result, the MAPbI3 perovskite with 10% GuSCN exhibits superior power conversion efficiency of 16.70% compared to the pristine MAPbI3 perovskite solar cell (15.57%). At the same time, the MAPbI3 perovskite solar cell with GuSCN additive shows better stability, power conversion efficiency retains ∼90% of its initial value compared to only ∼60% for pristine MAPbI3 perovskite solar cells after being stored for 15 days without encapsulation
Nian, Heng,Cheng, Chenwen,Song, Yipeng The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.3
This paper develops a coordinated control strategy of the doubly fed induction generator (DFIG) system based on repetitive control (RC) under generalized harmonic grid voltage conditions. The proposed RC strategy in the rotor side converter (RSC) is capable of ensuring smooth DFIG electromagnetic torque that will enable the possible safe functioning of the mechanical components, such as gear box and bearing. Moreover, the proposed RC strategy in the grid side converter (GSC) aims to achieve sinusoidal overall currents of the DFIG system injected into the network to guarantee satisfactory power quality. The dc-link voltage fluctuation under the proposed control target is theoretically analyzed. Influence of limited converter capacity on the controllable area has also been studied. A laboratory test platform has been constructed, and the experimental results validate the availability of the proposed RC strategy for the DFIG system under generalized harmonic grid voltage conditions.
Structure and bioactivity of triterpenoids from the stems of Schisandra sphenanthera
Cheng-Qin Liang,Rong-Hua Luo,Ju-Ming Yan,Yan Li,Xiao-Nian Li,Yi-Ming Shi,Shan-Zhai Shang,Zhong-Hua Gao,Liu-Meng Yang,Yong-Tang Zheng,Wei-Lie Xiao,Hong-Bin Zhang,Han Dong Sun 대한약학회 2014 Archives of Pharmacal Research Vol.37 No.2
Two new triterpenoids, schisphendilactoneA and B (1 and 2), together with three known triterpenoids,were isolated from the stems of Schisandra sphenanthera. Their structures were elucidated by spectroscopic methods,and the absolute configuration of 1 was determined bysingle-crystal X-ray diffraction. Compound 2 showedmoderate inhibitory activity against SW480 cancer cellline, and compound 5 exhibited promising anti-HIV-1activity with EC50 value of 0.52 lg ml-1 and therapeuticindex value of 117.12.
Nian Hong,Qin Cheng,Ashantha Goonetilleke,Erick R. Bandala,An Liu 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.89 No.-
This study investigated the role of surface hydrophobicity/hydrophilicity of biochar on its pollutantleaching potential (pollutants originally in biomass feedstock), including nutrients, organic matter andmetals, in water treatment applications. The study outcomes confirmed that biochar with greaterhydrophilic surface leached comparatively higher loads of nutrients and organic matter compared tobiochar with mostly hydrophobic surface, while biochar with greater hydrophilic surface leached lowermetal loads. This trend is attributed to the changes to the physical and chemical properties of biocharincluding specific surface area and surface functional groups, as well as being related to the binding forcesbetween the biochar surface and the different compounds. Further, the study results substantiated thesignificant influence of surface characteristics of biochar, and its preparation process on pollutantleaching potential. The study outcomes provide essential guidance on the appropriate use of biochar asan adsorbent in water treatment, including raw biomass selection and the production processes to beadopted.
Heng Nian,Chenwen Cheng,Yipeng Song 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.3
This paper develops a coordinated control strategy of the doubly fed induction generator (DFIG) system based on repetitive control (RC) under generalized harmonic grid voltage conditions. The proposed RC strategy in the rotor side converter (RSC) is capable of ensuring smooth DFIG electromagnetic torque that will enable the possible safe functioning of the mechanical components, such as gear box and bearing. Moreover, the proposed RC strategy in the grid side converter (GSC) aims to achieve sinusoidal overall currents of the DFIG system injected into the network to guarantee satisfactory power quality. The dc-link voltage fluctuation under the proposed control target is theoretically analyzed. Influence of limited converter capacity on the controllable area has also been studied. A laboratory test platform has been constructed, and the experimental results validate the availability of the proposed RC strategy for the DFIG system under generalized harmonic grid voltage conditions.
Lien-Cheng Kao,Yu-Wen Liu,Nian-Sheng Tzeng,Terry B. J. Kuo,San-Yuan Huang,Chuan-Chia Chang,Hsin-An Chang 대한신경정신의학회 2016 PSYCHIATRY INVESTIGATION Vol.13 No.4
ObjectiveaaAnxiety trait, anxiety and depression states have all been reported to increase risks for cardiovascular disease (CVD), possibly through altering cardiac autonomic regulation. Our aim was to investigate whether the relationship between harm avoidance (HA, an anxiety-related personality trait) and cardiac autonomic regulation is independent of anxiety and depression states in healthy adults. MethodsaaWe recruited 535 physically and mentally healthy volunteers. Participants completed the Beck Anxiety Inventory (BAI), Beck Depression Inventory (BDI) and Tri-dimensional Personality Questionnaire. Participants were divided into high or low HA groups as discriminated by the quartile value. Cardiac autonomic function was evaluated by measuring heart rate variability (HRV). We obtained the time and frequency-domain indices of HRV including variance (total HRV), the low-frequency power (LF; 0.05–0.15 Hz), which may reflect baroreflex function, the high-frequency power (HF; 0.15–0.40 Hz), which reflects cardiac parasympathetic activity, as well as the LF/HF ratio. ResultsaaThe BDI and HA scores showed associations with HRV parameters. After adjustment for the BDI scores and other control variables, HA is still associated with reduced variance, LF and HF power. Compared with the participants with low HA, those with high HA displayed significant reductions in variance, LF and HF power and a significant increase in their LF/HF ratio. ConclusionaaThis study highlights the independent role of HA in contributing to decreased autonomic cardiac regulation in healthy adults and provides a potential underlying mechanism for anxiety trait to confer increased risk for CVD.
Rui-cheng Feng,Yong-nian Qi,Zong-xiao Zhu,Wen-yuan Song,Hai-yan Li,Mao-mao Wang,Zhi-yuan Rui,Feng-shou Gu 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.4
Molecular dynamics, an eff ective method to gain an insight into nanometric behaviour of materials, was employed to studythe nano-cutting behaviour of single crystal Ni 3 Al in nanometric scale. In this paper, comparisons were made for compressive/tensile stress, subsurface damage and surface roughness with three rake angles of a diamond tool. Subsurface damage waspartitioned by region and studied with work hardening in detail. A model for precise characterization of surface roughnesswas established with consideration of local surface fl uctuation. Simulation results showed that the chip thickness increasedas rake angle changed from negative to positive, and the boundary formed between tensile and compressive stress was inconsistent with the glide direction of stacking fault. Subsurface damage decreased as the increase of rake angle, and regularglide planes of stacking faults were found in front of the cutting tool. Further, the pinned dissociated 1/2 < 110 > superpartialdislocation with anti-phase boundary was demonstrated. The model was tested and characterized by implanted pits onperfect surface. Results showed that surface roughness can be well characterized, and an evident discrepancy was observedamong three rake angles, especially for 30° rake angle, which showed an distinct smooth surface compared with the others.
Motor Model-based Optimal Robust Guaranteed Cost Control for Two-motor Web-winding System
Hongyun Xiong,Yipeng Lv,Bin Cheng,Xiaohong Nian,Xiaoyan Chu 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.11
In this paper, a novel comprehensive model for the two-motor web-winding system is proposed, which combines the classical web-winding system model with the driven-motor model. Based on the proposed model, the state feedback robust control (SFRC) strategy is designed to handle systematic uncertainty and time-varying parameters. And then in order to reduce the control cost of the web-winding system, an optimal robust guaranteed cost control (ORGCC) approach is studied. First, the reference control inputs and error dynamic model are derived based on the proposed comprehensive model. Then, the SFRC strategy and ORGCC approach are designed to calculate control compensation. By regarding some suitable parameters as interval variables, the proposed controllers have good robustness for parameter variations and environmental disturbance. Finally, the simulation results illustrate the effectiveness of the proposed model and control.
A dynamic asymmetrical crack model of bridging fiber pull-out in unidirectional composite materials
Xin-gang Li,Yun-hong Cheng,Nian-chun Lü,Guo-dong Hao,Jin Cheng 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.9
As a rule, when a crack happens in composite materials, the fibrous system will generate bridging fibers resulted in the asymmetrical extending of the crack. In this paper, a dynamic asymmetrical crack model of bridging fiber pull-out in unidirectional composite materials is built for analyzing the distributions stress and displacement with the internal asymmetrical crack under the loading conditions of an applied non- stress and the traction forces on crack faces yielded by the bridging fiber pull-out model. Thus the fiber failure is determined by the maximum tensile stress, the fiber ruptures, and hence the crack propagation should also occur in self-similar modality. The formulation involves the development of a Riemann-Hilbert problem. The analytical solution of an asymmetrical extension crack in unidirectional composite materials under the conditions of moving increasing loads Pt²/x² and Px²/t is concluded, respectively. Based on relative material properties, the variable law of dynamic stress intensity factors was depicted perfectly. After the conclusion of analytical solutions with the superposition theorem, the solutions of arbitrary complex problems could be acquired.