11 results on '"Zhifeng Nie"'
Search Results
2. Synthesis and Performance of Deep-Red Phosphorescent Iridium Complexes with Pyrone as an Auxiliary Ligand
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Wen Jiang, Wenming Hou, Caixian Yan, Zhifeng Nie, Qiaowen Chang, Xiangguang Li, and Weiping Liu
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pyrone ,deep red ,iridium complex ,phosphorescent organic light-emitting diode (PhOLED) ,Organic chemistry ,QD241-441 - Abstract
Two bis-cyclometalated heteroleptic iridium complexes incorporating 1-phenylisoquinoline (piq) as the main cyclometalating ligand and 3-hydroxy-2-methyl-4-pyrone (ma) or 2-ethyl-3-hydroxy-4H-pyran-4-one (ema) as the auxiliary ligand, namely Ir(piq)2(ma) (Ir-1) and Ir(piq)2(ema) (Ir-2), were developed and applied as deep-red phosphors in organic light-emitting diodes (OLEDs). The two auxiliary ligands had similar influences on the photophysical, electrochemical, and electroluminescent properties of the iridium complexes. Ir(piq)2(ma) (Ir-1) showed better luminescence performance in a simple phosphorescent OLED compared to the traditional red iridium complex Ir(piq)2(acac) and exhibited a current efficiency of 9.39 cd A−1 (EQE of 12.09%). In contrast, Ir(piq)2(ema) exhibited an efficiency of 8.6 cd A−1 (EQE of 10.19%).
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- 2024
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3. An N-Rich Polymer for the Selective Recovery of Gold from Wastewater
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Haonan Dong, Ge Shang, Yi Zhang, Enrui Dai, Mingdong Shao, Chunfeng Chen, Hongxing He, Zhifeng Nie, Mingyang Xiong, Deren Miao, and Sibiao Zhao
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gold resource recovery ,selective adsorption ,adsorption mechanism ,adsorptiological modeling ,DFT calculations ,Organic chemistry ,QD241-441 - Abstract
The recovery of valuable gold from wastewater is of great interest because of the widespread use of the precious metal in various fields and the pollution generated by gold-containing wastes in water. In this paper, a water-insoluble cross-linked adsorbent material (TE) based on cyanuric chloride (TCT) and ethylenediamine (EDA) was designed and used for the adsorption of Au(III) from wastewater. It was found that TE showed extremely high selectivity (D = 49,213.46) and adsorption capacity (256.19 mg/g) for Au(III) under acidic conditions. The adsorption rate remained above 90% eVen after five adsorption–desorption cycles. The adsorption process followed the pseudo-first-order kinetic model and the Freundlich isotherm model, suggesting that physical adsorption with a multilayer molecular overlay dominates. Meanwhile, the adsorption mechanism was obtained by DFT calculation and XPS analysis, and the adsorption mechanism was mainly the electrostatic interaction and electron transfer between the protonated N atoms in the adsorbent (TE) and AuCl4−, which resulted in the redox reaction. The whole adsorption process was the result of the simultaneous action of physical and chemical adsorption. In conclusion, the adsorbent material TE shows great potential for gold adsorption and recovery.
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- 2024
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4. Magnetic Ion-Imprinted Materials for Selective Adsorption of Cr(VI): Adsorption Behavior and Mechanism Study
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Shunfei Li, Siqing Ye, Weiye Zhang, Hongxing He, Yi Zhang, Mingyang Xiong, Yuhan Chen, Mingqiu Wang, and Zhifeng Nie
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ion-imprinted polymer ,Cr(VI) capture ,magnetic separation ,density functional theory (DFT) ,Organic chemistry ,QD241-441 - Abstract
With the increase of hexavalent Cr(VI) wastewater discharged from industrial production, it seriously pollutes water bodies and poses a risk to human health. Adsorption is used as an effective means to treat Cr(VI), but its effectiveness is affected by pH, and the adsorption performance decreases when acidity is strong. Furthermore, research on the mechanism of Cr(VI) adsorption using DFT calculations needs to be developed. This study focuses on the development of magnetically responsive core–shell nano-ion imprinted materials (Fe3O4@GO@IIP) through magnetic separation and surface imprinting techniques. Characterization techniques including FT-IR, XRD, and EDS confirmed the core–shell nanostructure of Fe3O4@GO@IIP. Batch adsorption experiments and model simulations demonstrated the exceptional adsorption capacity of Fe3O4@GO@IIP for Cr(VI) in strongly acidic solutions (pH = 1), reaching a maximum of 89.18 mg/g. The adsorption mechanism was elucidated through XPS and DFT calculations, revealing that Fe3O4@GO@IIP operates through electrostatic interactions and chemical adsorption, with charge transfer dynamics quantified during the process. This research provides new insights for addressing Cr(VI) treatment in highly acidic environments.
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- 2024
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5. A Triazine Membrane for Sustainable Acquisition of Au(III) from Wastewater
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Ge Shang, Haonan Dong, Yi Zhang, Conghuan Zhang, Ting Chen, Yunhua He, Hongxing He, Weili Li, Xiujun Deng, Zhifeng Nie, and Sibiao Zhao
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gold adsorption ,selectivity ,triazine membrane ,phase transition method ,DFT calculations ,Organic chemistry ,QD241-441 - Abstract
The recovery of Au(III) from solution using adsorbents in the form of granules or powders is challenging due to issues such as instability during the recovery process or mass loss caused by small particle size. This study introduces a PEI-TCT/PVDF composite membrane designed to intercept and capture Au(III) in wastewater. Experimental results demonstrated that the PEI-TCT/PVDF membrane exhibits a broad pH range (1–8) and a high retention efficiency for Au(III) of 97.8%, with a maximum adsorption capacity of 294.5 mg/g. The mechanism of Au(III) adsorption on the PEI-TCT/PVDF membrane was mainly through electrostatic adsorption, which caused AuCl4− to aggregate on the surface of the membrane and gradually reduced to Au0 and Au+. Furthermore, the membrane can be entirely regenerated within 20 min and maintains its performance in subsequent adsorption cycles. This study highlights the potential of PEI-TCT/PVDF membranes for the recovery of precious Au(III).
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- 2024
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6. PD-Based Iterative Learning Control for the Nonlinear Low-Speed-Jitter Vibration of a Wind Turbine in Yaw Motion
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Tingrui Liu and Zhifeng Nie
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low-speed jitter ,yaw system ,dynamic modeling ,PD control ,iterative learning control ,hardware-in-the-loop simulation ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Aiming at the nonlinear low-speed-jitter (LSJ) vibration suppression for a yaw system of a megawatt wind turbine, a kinematics mechanism of the yaw system is investigated from the perspective of tribology, and a kinematics model of the yaw system based on an equilibrium position is established. On the basis of the dynamic modeling of the yaw system, a nonlinear mathematical model of the LSJ system is deduced. Based on the two lead motors’ driving of the conventional yaw motion, an innovative design with a special installation of two auxiliary motors for yaw transmission is carried out, which is integrated with a matching centralized lubrication system (CLS). Based on open-loop proportional-derivative (PD) control and the iterative learning control methods of the time-varying continuous system, the stability control and jitter amplitude suppression of the yaw system are realized by using a combined driving torque provided by the lead and auxiliary gears. From the stability and convergence of the time-domain response and the convergence of the iterative error, the effectiveness of the iterative learning control method with the PD-based regulation is verified, and its advantages for engineering applications are shown based on the algorithm solver improvement. The feasibility of the physical realization and engineering application of the control methodology is verified by using controller-hardware-in-the-loop (C-HITL) simulation technology.
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- 2024
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7. The Adsorption Mechanisms of SF6-Decomposed Species on Tc- and Ru-Embedded Phthalocyanine Surfaces: A Density Functional Theory Study
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Rou Xue, Wen Jiang, Xing He, Huihui Xiong, Gang Xie, and Zhifeng Nie
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adsorption mechanism ,metal phthalocyanine monolayer ,SF6-decomposed species ,density functional theory ,Organic chemistry ,QD241-441 - Abstract
Designing high-performance materials for the detection or removal of toxic decomposition gases of sulfur hexafluoride is crucial for both environmental monitoring and human health preservation. Based on first-principles calculations, the adsorption performance and gas-sensing properties of unsubstituted phthalocyanine (H2Pc) and H2Pc doped with 4d transition metal atoms (TM = Tc and Ru) towards five characteristic decomposition components (HF, H2S, SO2, SOF2, and SO2F2) were simulated. The findings indicate that both the TcPc and RuPc monolayers are thermodynamically and dynamically stable. The analysis of the adsorption energy indicates that H2S, SO2, SOF2, and SO2F2 underwent chemisorption on the TcPc monolayer. Conversely, the HF molecules were physisorbed through interactions with H atoms. The chemical adsorption of H2S, SO2, and SOF2 occurred on the RuPc monolayer, while the physical adsorption of HF and SO2F2 molecules was observed. Moreover, the microcosmic mechanism of the gas–adsorbent interaction was elucidated by analyzing the charge density differences, electron density distributions, Hirshfeld charges, and density of states. The TcPc and RuPc monolayers exhibited excellent sensitivity towards H2S, SO2, and SOF2, as evidenced by the substantial alterations in the band gaps and work functions of the TcPc and RuPc nanosheets. Our calculations hold significant value for exploring the potential chemical sensing applications of TcPc and RuPc monolayers in gas sensing, with a specific focus on detecting sulfur hexafluoride.
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- 2023
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8. Novel Strategy for Organic Cocrystals of n‑Type and p‑Type Organic Semiconductors with Advanced Optoelectronic Properties
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Taoyu Zou, Jiawei Chang, Qiuyuan Chen, Zhifeng Nie, Liangfei Duan, Tingting Guo, Yumin Song, Wei Wu, and Hai Wang
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Chemistry ,QD1-999 - Published
- 2020
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9. Metal Embedded Phthalocyanine Monolayers as Promising Materials for Toxic Formaldehyde Gas Detection: Insights from DFT Calculations
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Rou Xue, Chen Wang, Yajun Wang, Qijun Guo, Enrui Dai, and Zhifeng Nie
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transition metal phthalocyanine ,formaldehyde ,DFT computations ,surface adsorption ,Mining engineering. Metallurgy ,TN1-997 - Abstract
The design of the good-performance materials for toxic formaldehyde (CH2O)-gas-detection is critical for environmental preservation and human health. In this work, density functional theory (DFT) calculations were employed to investigate the adsorption behavior and electronic properties of CH2O on transition metal (TM)-doped phthalocyanine monolayers. Our results prove that PdPc and RuPc monolayers are thermodynamically stable. Analysis of the adsorption energy showed that the CH2O gas molecule was chemisorbed on the RuPc monolayer, while it was physisorbed on the PdPc nanosheet. The microcosmic interaction mechanism within the gas-adsorbent system was revealed by analyzing the density of states, the charge-density difference, the electron-density distribution, and the Hirshfeld charge transfer. Additionally, the RuPc monolayer was highly sensitive to CH2O due to the obvious changes in electrical conductivity, and the recovery time of CH2O molecule was predicted to be 2427 s at room temperature. Therefore, the RuPc monolayer can be regarded as a promising gas-sensing material for CH2O detection.
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- 2022
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10. Economic burden and healthcare resource utilization of childhood atopic dermatitis in China.
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Zhifeng Nie, Ruowei Xiao, Jiafang Song, Sheng Han, Wei Li, He Zhu, and Luwen Shi
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ATOPIC dermatitis , *EMERGENCY room visits , *CHILD patients , *CONVENIENCE sampling (Statistics) , *CHINESE medicine , *PILOCARPINE , *COST estimates - Abstract
The primary objective of this study was to estimate the costs and healthcare resource utilization (HCRU) associated with atopic dermatitis (AD) in Chinese pediatric patients and to investigate the factors contributing to the costs of AD. This cross-sectional study employed a convenience sampling approach, with patient-level data obtained from a nationwide survey conducted across 31 provinces in China between February and March of 2022, utilizing an internet-based questionnaire. Caregivers of children under 18 years old with a physician-confirmed diagnosis of atopic dermatitis were recruited, and sociodemographic information, clinical characteristics, HCRU data, time spent on caregiving, and disease-related costs were collected from all eligible participants. A total of 599 eligible families were included in the study. Among them, 82.5% of families reported that their child had at least one outpatient or emergency room visit, while 5.8% of families reported that their child had been hospitalized in the past 12 months. The average annual cost across all cost categories amounted to 28 591.92 yuan per patient per year (PPPY), with 92.8% attributed to direct costs. Out-of-pocket expenses accounted for 90.7% of the cost of outpatient or emergency room visits and 43.4% of the cost of hospitalization. Factors associated with higher annual total costs included moderate (coefficient ± SE: 0.22 ± 0.09, P = 0.012) and severe AD patient groups (coefficient ± SE: 0.58 ± 0.15, P < 0.001), onset of AD on the head, neck, or hands (coefficient ± SE: 0.57 ± 0.14, P < 0.001), use of biological agents (coefficient ± SE: 0.64 ± 0.11, P < 0.001), and use of traditional Chinese medicine (TCM) (coefficient ± SE: 0.26 ± 0.09, P = 0.003), compared with their respective reference groups. This study highlighted a considerable economic burden of AD among pediatric patients in China across different disease severity groups, with significantly higher costs observed in patients with more severe disease. Additionally, factors such as disease severity, clinical characteristics, and treatment modalities might contribute to the higher costs encountered by pediatric patients with AD. [ABSTRACT FROM AUTHOR]
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- 2024
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11. Impact of the zero-markup drug policy on volume of medical service: based on 57 county hospitals of China.
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Zhifeng Nie, Chunxia Man, Xin Yi, Yi Liu, Zhigang Guo, Xiaodong Guan, and Luwen Shi
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DRUG control , *HEALTH policy , *FIXED effects model , *MEDICAL records , *ABORTIFACIENTS , *HOSPITALS , *LONG-term care facilities - Abstract
In the present study, we aimed to assess the long-term impact of zero-markup drug policy on volume of medical service in county hospitals of China. This study used 57 county hospitals' records of medical service from 2011 to 2015, and a fixed effect model was applied to examine the impact of the zero-markup drug policy on volume of medical service. The outcome indicators included the number of patient visits, the number of prescriptions, the number of discharged patients, the length of stay, the number of patients who had surgeries and the number of patients who had CT or MRI, monthly. The number of hospitals which implemented the zero-markup drug policy was increased continuously. By the end of 2015, 41 hospitals (71.9%) implemented this policy. The panel regression showed that most indicators were insignificantly decreased, including the number of patient visits (P<0.01), the length of stay (P<0.05), the number of patients who had surgeries (P<0.01) and the number of patients who had CT or MRI (P<0.01). However, the number of prescriptions and the number of discharged patients were not significantly changed. The implementation of the zero-markup drug policy might affect the reduction of the volume of medical service in county-level hospitals and the reason needs to be clarified in future studies. [ABSTRACT FROM AUTHOR]
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- 2020
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