16 results on '"Liu, Xingmin"'
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2. Mechanistic Investigation of Oxidative Methanol Carbonylation with Mixed Cu(I)/Cu(II)–N-Methylimidazole Catalysts
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Li, Guoxin, Wang, Shiwei, Liu, Xingmin, Wen, Zicheng, Huang, Shouying, Lv, Jing, and Ma, Xinbin
- Abstract
Copper complex catalysts exhibit excellent activity for the oxidative carbonylation of methanol to produce dimethyl carbonate (DMC). However, the reaction mechanism over Cu(I) or Cu(II) complex catalysts is not fully understood. In this study, homogeneous CuCl/CuCl2–NMI-m/n(N = N-methylimidazole; m/n= molar ratio of Cu(I) and Cu(II)) catalysts with organic ligand coordination are designed for oxidative carbonylation. The optimized CuCl/CuCl2–NMI-0.3/0.7 catalyst showed a TOF as high as 3.4 h–1and a DMC selectivity of 67.2% based on oxygen, which were superior to those of CuCl–NMI or CuCl2–NMI. Our experiments suggested that the high activity and selectivity were assigned to the synergistic effect between Cu(I) and Cu(II), in which Cu(I) and Cu(II) are mainly responsible for the rapid generation of copper carbonyl and copper methoxy intermediates, respectively. This synergistic effect not only enhances the reaction activity but also ensures high DMC selectivity.
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- 2024
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3. Strain Sensors Made of MXene, CNTs, and TPU/PSF Asymmetric Structure Films with Large Tensile Recovery and Applied in Human Health Monitoring.
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Cui, Xiaoyu, Miao, Chengjing, Lu, Shaowei, Liu, Xingmin, Yang, Yuxuan, and Sun, Jingchao
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- 2023
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4. Strain Sensors Made of MXene, CNTs, and TPU/PSF Asymmetric Structure Films with Large Tensile Recovery and Applied in Human Health Monitoring
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Cui, Xiaoyu, Miao, Chengjing, Lu, Shaowei, Liu, Xingmin, Yang, Yuxuan, and Sun, Jingchao
- Abstract
Designing flexible wearable sensors with a wide sensing range, high sensitivity, and high stability is a vulnerable research direction with a futuristic field to study. In this paper, Ti3C2TxMXene/carbon nanotube (CNT)/thermoplastic polyurethane (TPU)/polysulfone (PSF) composite films with excellent sensor performance were obtained by self-assembly of conductive fillers in TPU/PSF porous films with an asymmetric structure through vacuum filtration, and the porous films were prepared by the phase inversion method. The composite films consist of the upper part with finger-like “cavities” filled by MXene/CNTs, which reduces the microcracks in the conductive network during the tensile process, and the lower part has smaller apertures of a relatively dense resin cortex assisting the recovery process. The exclusive layer structure of the MXene/CNTs/TPU/PSF film sensor, with a thickness of 46.95 μm, contains 0.0339 mg/cm2single-walled carbon nanotubes (SWNTs) and 0.348 mg/cm2MXene only, providing functional range (0–80.7%), high sensitivity (up to 1265.18), and excellent stability and durability (stable sensing under 2300 fatigue tests, viable to the initial resistance), endurably cycled under large strains with serious damage to the conductive network. Finally, the MXene/CNTs/TPU/PSF film sensor is usable for monitoring pulse, swallow, tiptoe, and various joint bends in real time and distributing effective electrical signals. This paper implies that the MXene/CNTs/TPU/PSF film sensor has broad prospects in pragmatic applications.
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- 2023
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5. Ultrathin, flexible CNTs@MXene film fabricated with electrophoretic deposition method for high-performance electromagnetic interference shielding
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Tong, Jinling, Yang, Dongxu, Liu, Xingmin, Lu, Shaowei, Wang, Jijie, Zheng, Boxiong, Zhao, Zihan, and Song, Yutong
- Abstract
Graphical abstract:
- Published
- 2023
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6. Plasma induced dynamic coupling of microscopic factors to collaboratively promote EM losses coupling of transition metal dichalcogenide absorbers
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Wen, Jiaming, Chen, Geng, Hui, Shengchong, Li, Zijing, Yun, Jijun, Fan, Xiaomeng, Zhang, Limin, He, Qian, Liu, Xingmin, and Wu, Hongjing
- Abstract
Plasma as the fourth state of matter has attracted great attention for material surface modification, which could induce changes in material microscopic factors, such as defects, phase transitions, crystallinity, and so on. However, the interactions among those microscopic factors and regulation mechanism of macroscopic properties have rarely been investigated. Two-dimensional (2D) transition metal dichalcogenide with tunable structure and phase is one of the most promising electromagnetic wave (EMW) absorbers, which provides a favorable platform for systematically studying the dynamic coupling of its microscopic factors. Herein, we constructed a NaBH4solution-assisted Ar plasma method to modify the 2H-MoS2and 1T-WS2for exploring the regulation mechanism of microscopic factors. For MoS2and WS2, NaBH4solution-assisted Ar plasma treatment behaves with different effects on dielectric responses, realizing dynamic coupling of material microscopic factors to collaboratively promote EM losses coupling. Consequently, the MS-D3-0.5 (MoS2, 3 kV voltage, 0.5 mol L−1NaBH4solution) displays an optimum effective absorption bandwidth of 8.01 GHz, which is 319.4 % more than that of MS-raw sample. This study not only reveals the novel mechanism of plasma induced dynamic coupling of microscopic factors for EMW dissipation, but also presents a new method of plasma-dominated surface modification to optimize the EMW absorption performance.
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- 2024
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7. In situ growth of CoO on MXene sheets for modification of all‑vanadium redox flow battery electrodes
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Zhao, Zihan, Song, Yutong, Liu, Xingmin, Zhang, Liping, Lu, Shaowei, Nong, Zhisheng, Wang, Sai, Wang, Jijie, and Li, Hongmei
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In order to greatly improve the energy efficiency and electrolyte utilization efficiency of vanadium redox flow batteries (VRFBs) and to enable them to operate at high current densities, MXene/CoO composites were used for the first time in this research as electrocatalysts for the V3+/V2+reaction. The catalytic effect of the materials was characterized by cyclic voltammetry (CV) and electrochemical impedance spectra (EIS) tests. Then battery performance of MXene/CoO composite modified plasma-treated graphite felt (GF) negative electrodes (MXene/CoO/GF) were tested in a VRFB. The results show that MXene/CoO composites can improve the catalytic activity. There is a 22.93 % increase in energy efficiency and 124.94 % increase in electrolyte utilization efficiency when MXene/CoO/GF is applied as VRFB negative electrode at a current density of 200 mA cm−2compared to GF. At a current density of 250 mA cm−2, the energy efficiency of MXene/CoO/GF is maintained at 75.55 %. The excellent performance is attributed to the addition of MXene/CoO, which increases the active sites for redox reactions and thus improves the kinetics of the V3+/V2+reaction.
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- 2024
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8. Ultra-light, high flexible and efficient CNTs/Ti3C2-sodium alginate foam for electromagnetic absorption application.
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Liu, Xingmin, Chai, Nan, Yu, Zhaoju, Xu, Hailong, Li, Xinliang, Liu, Jiquan, Yin, Xiaowei, and Riedel, Ralf
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SODIUM alginate ,FOAM ,REFLECTANCE ,CARBON nanotubes ,ABSORPTION ,SCANNING electron microscopy - Abstract
Ultra-light carboxylic functionalized multi-walled carbon nanotubes (CNTs-COOH) and Ti 3 C 2 MXene hybrids modified sodium alginate (CNTs/Ti 3 C 2 -SA) based composite foams were prepared through ice-templated freeze-drying method. The microstructure of the synthesized CNTs/Ti 3 C 2 hybrids and CNTs/Ti 3 C 2 -SA foams is characterized by the presence of CNTs inserted between MXene layers which prevents their restacking. The resultant CNTs/Ti 3 C 2 hybrids exhibit a unique sandwich-like hierarchical structure. Scanning electron microscopy (SEM) images show that the CNTs/Ti 3 C 2 -SA foam exhibits a heterogeneous anisotropic microstructure and CNTs/Ti 3 C 2 hybrids are homogeneously dispersed in the skeleton of the porous foam. In case that the content of the hybrids amounts 40 mg/cm
3 , the CNTs/Ti 3 C 2 -SA foam possesses excellent electromagnetic (EM) absorption performance with a minimum reflection coefficient (RC min) as low as -40.0 dB. In case of a sample thickness of 3.95 mm, the RC min reaches -24.4 dB and the effective absorption bandwidth covers the whole X band from 8.2 to 12.4 GHz. A control test shows that, with the same absorbent content, the CNTs/Ti 3 C 2 -SA foam exhibits a far better EM performance than that of CNT-free Ti 3 C 2 -SA foam. [ABSTRACT FROM AUTHOR]- Published
- 2019
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9. Review of Critical Success Factors (CSFs) for green building projects.
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Li, Yuanyuan, Song, Huanbin, Sang, Peidong, Chen, Po-Han, and Liu, Xingmin
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CRITICAL success factor ,GREEN business ,KNOWLEDGE gap theory ,PROJECT managers - Abstract
In the past decade, many efforts have been devoted to exploring the Critical Success Factors (CSFs) for Green Building (GB) projects. However, there is absence of a systematic review exploring these studies. Therefore, the paper presents a comprehensive review of publications from 2005 to 2018 on CSFs for GB projects. The results indicate there is a growing interest in the exploration of CSFs for GB projects since 2010. The main contributing contributors, institutions, countries and areas, as well as research methods in this area are summarized. The mostly identified CSFs for GB projects are "communication and cooperation between project participants", "effective project planning and control", "owner's involvement and commitment", "clear goals and objectives" and "project manager's performance". The contractors and owners were found more related to these identified CSFs. Finally, knowledge gaps are discussed and future research directions including: (1) more studies on relationships between the CSFs; (2) extending studies to cover all building types; (3) more investigation on CSFs for different project objectives; (4) more emphasis on how to implement CSFs for GB projects are proposed. The results could offer a favorable reference for researchers to obtain a thorough picture of the current research woks and facilitate further study in this area. The discussion of GB CSFs could also broaden the understanding of the best ways for implementing GB projects to practitioners thereby reducing the setbacks towards its implementation. • Studies on Critical Success Factors (CSFs) for green building projects were systematically reviewed. • Our focus was to review papers published from 2005 to 2018. • Most adopted research methods in this field were presented. • CSFs of green building projects in previous researches and their related project stakeholders were identified and discussed. • Future research directions in green building projects were proposed. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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10. Quantitative monitoring of impact damage to composite structures using blade coated MXene sensors
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Wang, QingXuan, Ma, ChengKun, Yang, DongXu, Lu, ShaoWei, Liu, XingMin, Guo, YiLin, and Hu, XiaoFan
- Abstract
Low velocity impacts usually cause invisible damage of composite structure,which is hard to be found and will cause catastrophic failure. In this work, the blade-coated MXene sensor was used to monitor impact damage of composite laminates. For the purpose of impact monitoring, an experiment was designed where composite laminates were subjected to controlled energy impacts. A circular sensor with a diameter of 100 mm was arranged on the back of the laminate. And ultrasonic C-scan was used to examine delamination damage of laminates after each impact. The experimental results show that the sensor identifies the onset of impact and the generation of damage. And the relative resistance changes of the sensor have a directly linear proportional relationship to the delamination size. There is also a functional relationship between the electrical response of the sensor and the impact energy. The findings are of great significance for the application of composite structure, and can effectively avoid the safety hazards caused by invisible impact delamination damage.
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- 2023
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11. The intrinsic effects of oxygen vacancy and doped non-noble metal in TiO2(B) on photocatalytic oxidation VOCs by visible light driving.
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Liu, Xingmin, Zheng, Jianfeng, Peng, Kun, Qin, Guozhen, Yang, Yatao, and Huang, Zhanggen
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VISIBLE spectra ,PHOTOCATALYTIC oxidation ,TITANIUM dioxide ,FRONTIER orbitals ,METALS ,ELECTRON-hole recombination ,REACTIVE oxygen species - Abstract
Constructing effective photocatalysts with visible-light-driven for degrading VOCs including formaldehyde remains a challenge. The TiO 2 (B) photocatalyst with a two-dimensional lamellar structure was prepared and modified by surface engineering. The DFT calculation results showed new impurity levels appeared among the energy bands of the modified TiO 2 (B) materials. These photocatalysts exhibited different rates of HCHO degradation under visible light. A variety of characterizations demonstrated that the surface defects greatly reduced the bandgap and enhanced the absorption of visible light. And the recombination of photogenerated electron-hole (e
- -h+ ) pairs was suppressed to varying degrees in the modulated TiO 2 (B) catalysts revealed in the photoelectrochemical analysis. It is necessary to match the band structure of photocatalysts with the frontier orbital of HCHO for achieving effectual photocatalytic oxidation (PCO). Remarkably, the separation and transport of photogenerated carriers were inhibited when excessive metal Cu was doped. The results in this work provide a deeper understanding of the relationship between the surface engineering of TiO 2 (B)-based catalysts and catalytic performance. [Display omitted] • Cu was anchored on TiO 2 (B) nanosheets through in situ icing-assisted photocatalytic doping method. • TiO 2 (B)-based catalysts showed potential for photocatalytic oxidation HCHO under visible light. • Matching the electronic structure of photocatalysts with the frontline orbital of pollutant was crucial factor. • The transport and separation of photogenerated carriers was inhibited when excessive Cu was doped. [ABSTRACT FROM AUTHOR]- Published
- 2022
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12. Damage monitoring and locating of COPV under low velocity impact using MXene sensor array
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Zhang, Lu, Qu, Xiaoqiang, Lu, Shaowei, Liu, Xingmin, Ma, Chengkun, Jiang, Xiaowei, and Wang, Xiaoqiang
- Abstract
The composite overwrapped pressure vessel (COPV) is sensitive to impact, and even small impact damage may cause serious consequences. So the structural health monitoring of COPV is incredibly crucial, and a highly sensitive sensor is urgently needed to monitor dangerous areas. In this paper, the force-electric response characteristics of MXene sensor are investigated in low velocity impact experiments, and the impact behaviors of COVP are monitored by this sensor array. The experimental results show that the MXene sensor is very sensitive to low energy impact. Moreover, the response of the near-end sensor is opposite to that of the far-end sensor. According to the combined response of sensor array, the magnitude of impact energy and the position of the impact point can be determined. In addition, the sensor can respond to the strain load generated by resonance to ensure the safety factor of COPV. In a word, the impact force and damage degree of COPV can be monitored effectively using MXene sensor array in real-time.
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- 2022
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13. TrustGWAS: A full-process workflow for encrypted GWAS using multi-key homomorphic encryption and pseudorandom number perturbation
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Yang, Meng, Zhang, Chuwen, Wang, Xiaoji, Liu, Xingmin, Li, Shisen, Huang, Jianye, Feng, Zhimin, Sun, Xiaohui, Chen, Fang, Yang, Shuang, Ni, Ming, Li, Lin, Cao, Yanan, and Mu, Feng
- Abstract
The statistical power of genome-wide association studies (GWASs) is affected by the effective sample size. However, the privacy and security concerns associated with individual-level genotype data pose great challenges for cross-institutional cooperation. The full-process cryptographic solutions are in demand but have not been covered, especially the essential principal-component analysis (PCA). Here, we present TrustGWAS, a complete solution for secure, large-scale GWAS, recapitulating gold standard results against PLINK without compromising privacy and supporting basic PLINK steps including quality control, linkage disequilibrium pruning, PCA, chi-square test, Cochran-Armitage trend test, covariate-supported logistic regression and linear regression, and their sequential combinations. TrustGWAS leverages pseudorandom number perturbations for PCA and multiparty scheme of multi-key homomorphic encryption for all other modules. TrustGWAS can evaluate 100,000 individuals with 1 million variants and complete QC-LD-PCA-regression workflow within 50 h. We further successfully discover gene loci associated with fasting blood glucose, consistent with the findings of the ChinaMAP project.
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- 2022
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14. The intrinsic effects of oxygen vacancy and doped non-noble metal in TiO2(B) on photocatalytic oxidation VOCs by visible light driving
- Author
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Liu, Xingmin, Zheng, Jianfeng, Peng, Kun, Qin, Guozhen, Yang, Yatao, and Huang, Zhanggen
- Abstract
Constructing effective photocatalysts with visible-light-driven for degrading VOCs including formaldehyde remains a challenge. The TiO2(B) photocatalyst with a two-dimensional lamellar structure was prepared and modified by surface engineering. The DFT calculation results showed new impurity levels appeared among the energy bands of the modified TiO2(B) materials. These photocatalysts exhibited different rates of HCHO degradation under visible light. A variety of characterizations demonstrated that the surface defects greatly reduced the bandgap and enhanced the absorption of visible light. And the recombination of photogenerated electron-hole (e--h+) pairs was suppressed to varying degrees in the modulated TiO2(B) catalysts revealed in the photoelectrochemical analysis. It is necessary to match the band structure of photocatalysts with the frontier orbital of HCHO for achieving effectual photocatalytic oxidation (PCO). Remarkably, the separation and transport of photogenerated carriers were inhibited when excessive metal Cu was doped. The results in this work provide a deeper understanding of the relationship between the surface engineering of TiO2(B)-based catalysts and catalytic performance.
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- 2022
- Full Text
- View/download PDF
15. Highly Sensitive and Stretchable MXene/CNTs/TPU Composite Strain Sensor with Bilayer Conductive Structure for Human Motion Detection
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Dong, Hui, Sun, Jingchao, Liu, Xingmin, Jiang, Xiaodan, and Lu, Shaowei
- Abstract
The universal application of wearable strain sensors in various situations for human-activity monitoring is considerably limited by the contradiction between high sensitivity and broad working range. There still remains a huge challenge to design sensors featuring simultaneous broad working range and high sensitivity. Herein, a typical bilayer-conductive structure Ti3C2TxMXene/carbon nanotubes (CNTs)/thermoplastic polyurethane (TPU) composite film was developed by a simple and scalable vacuum filtration process utilizing a porous electrospun thermoplastic polyurethane (TPU) mat as a skeleton. The MXene/CNTs/TPU strain sensor is composed of two parts: a brittle densely stacked MXene upper lamella and a flexible MXene/CNT-decorated fibrous network lower layer. Benefiting from the synergetic effect of the two parts along with hydrogen-bonding interactions between the porous TPU fiber mat and MXene sheets, the MXene/CNTs/TPU strain sensor possesses both a broad working range (up to 330%) and high sensitivity (maximum gauge factor of 2911) as well as superb long-term durability (2600 cycles under the strain of 50%). Finally, the sensor can be successfully employed for human movement monitoring, from tiny facial expressions, respiration, and pulse beat to large-scale finger and elbow bending, demonstrating a promising and attractive application for wearable devices and human–machine interaction.
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- 2022
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16. Sorption Behavior of Dye Compounds onto Natural Sediment of Qinghe River
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Liu, Ruixia, Liu, Xingmin, Tang, Hongxiao, and Su, Yongbo
- Abstract
The objective of this study is to assess the adsorption behavior of C.I. Basic Yellow X-5GL, C.I. Basic Red 13, C.I. Direct Blue 86, C.I. Vat Yellow 2, and C.I. Mordant Black 11 on natural sediment and to identify sediment characteristics that play a predominant role in the adsorption of the dyes. The potentiometric titration experiment is used to investigate acid–base properties of the sediment surface with a constant capacitance surface complexation model. The parameters controlling the sorption such as solution pH and ion strength, as well as the influence of organic carbon and Ca2+ion on the adsorption, are evaluated. It is shown that the titration data can be successfully described by the surface protonation and deprotonation model with the least-squares FITEQL program 2.0. The sorption isotherm data are fitted to the Freundlich equation in a nonlinear form (1/n=0.3–0.9) for all tested dyes. With increasing pH value, the sorption of C.I. Mordant Black 11 and C.I. Direct Blue 86 on the sediment decreases, while for C.I. Basic Yellow X-5GL and C.I. Basic Red 13, the extent of sorption slightly increases. In addition, ion strength also exhibits a considerably different effect on the sorption behavior of these dye compounds. The addition of Ca2+can greatly reduce the sorption of C.I. Basic Red 13 on the sediment surface, while it enhances the sorption of C.I. Direct Blue 6. The removal of organic carbon decreases the sorption of C.I. Mordant Black 11 and C.I. Direct Blue 86. In contrast, the sorption of C.I. Basic Red 13 and C.I. Basic Yellow X-5GL is obviously enhanced after the removal of organic carbon. The differences in adsorption behavior are mainly attributed to the physicochemical properties of these dye compounds.
- Published
- 2001
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