36 results on '"Jing-Hua Guo"'
Search Results
2. Theoretical Study On The Detection of Hachimoji Nucleobases Based On Molecular Junction
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Jia-Nan Tang, Jing-hua Guo, Gang Chen, and Ting-Ting Cao
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- 2023
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3. Singlet Oxygen Triggered by Carbon Doped Boron Nitride Nanosheets for Enhanced Removal of Tetracycline by Peroxymonosulfate Activation
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Qiling Zheng, Jing-hua Guo, Xiaohua Ren, weijie zhang, Hongjie Qing, Penghui Zhang, Shouwei Zhang, and Xijin Xu
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- 2023
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4. Theoretical study of hydrogen storage by spillover on porous carbon materials
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Jing-Hua Guo, Yan Su, Gang Chen, and Shu-Juan Li
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Materials science ,Hydrogen ,Renewable Energy, Sustainability and the Environment ,Graphene ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Catalysis ,law.invention ,Hydrogen storage ,Fuel Technology ,Adsorption ,chemistry ,Spillover effect ,law ,Chemical physics ,Hydrogen spillover ,0210 nano-technology ,Carbon - Abstract
Hydrogen storage by spillover in porous carbon material (PCM) has achieved great success in experiments. During the past 20 years, a large number of theoretical works have been performed to explore the hydrogen spillover mechanism, look for high-performance hydrogen storage materials and high-efficiency catalysts. In this paper, we summarize and analyze the results of the past researches, and draw the following conclusions: (1) In PCM surface, the stability of chemisorbed H can be reached through phase nucleation process, which can be initiated in the vicinity of surface impurities or defects. (2) To achieve the 2020 U.S. Department of Energy (DOE) target, the PCM material used for hydrogen storage by spillover should have a sp2 carbon ratio greater than 0.43 and a surface area less than 3500 m2/g, which gives us an inspiration for exploring hydrogen spillover materials. (3) Due to a high barrier, the hydrogen spillover almost can not be initiated on pure PCM substrate at room temperature. By introducing the defects or impurities (e.g. holes, carbon bridges, oxygen functional groups, boron atoms and fluorine atoms), the spillover barriers can be reduced to a reasonable range. In addition, hydrogen atoms may also migrate in a gas phase. (4) According to our previous results of kinetic Monte Carlo simulations, there is a linear relationship between the reaction temperature and the migration barrier. The optimal barrier for the hydrogen spillover should be in the range of 0.60–0.88 eV. (5) Once the hydrogen atoms are chemically adsorbed on the carbon substrate, it is difficult to diffuse again due to the strong strength of C–H bond. Several theoretical diffusion mechanisms have been proposed. For example, the H atoms in physisorption state can diffuse freely on carbon surfaces with high mobility, using the shuttle gases (e.g. BH−4, H2O, HF and NH3) to make the migration thermodynamically possible and decrease the migration barrier, the H atoms diffuse inside the interlayer space of the bi- and tetralayer graphene, and introducing the impurities on the surface to facilitate the hydrogen diffusion. (6) The H desorption through the directly recombination or the reverse spillover is unlikely to occur at normal temperature. The Eley-Rideal reaction may be the only possible mechanism for desorption of the adsorbed H atoms in carbon substrate. Finally, we have made a prospect for further research works on hydrogen storage by spillover.
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- 2020
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5. Methylation Detection and DNA Sequencing Based on Adsorption of Nucleobases on Silicene Nanoribbon
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Yigeng Tian, Haiying Liu, Jing-Hua Guo, Qingxin Li, Gang Chen, and Jin Yong Lee
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Silicene ,Chemistry ,Graphene ,Nanotechnology ,02 engineering and technology ,Methylation ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,DNA sequencing ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,law.invention ,Nucleobase ,General Energy ,Adsorption ,law ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
Nanodevices based on two-dimensional materials hold great promise for DNA sequencing. Owing to some unique properties, silicene has become a potential alternative to the well-known graphene as a se...
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- 2020
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6. Combined Density Functional Theory and Kinetic Monte Carlo Study of Hydrogen Spillover on Fluorine-Decorating Covalent Organic Frameworks
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Xiao-Dong Li, Jing-Hua Guo, Shu-Juan Li, Haiying Liu, and Gang Chen
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Materials science ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Hydrogen storage ,General Energy ,chemistry ,Covalent bond ,Chemical physics ,Fluorine ,Density functional theory ,Kinetic Monte Carlo ,Physical and Theoretical Chemistry ,Hydrogen spillover ,0210 nano-technology - Abstract
How to reduce the H migration barrier in hydrogen spillover is one of the crucial points for hydrogen storage. In this study, we use COF-8 as a representative to study the effect of F decoration fo...
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- 2019
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7. Computer-aided prediction of structure and hydrogen storage properties of tetrakis(4-aminophenyl)silsesquioxane based covalent-organic frameworks
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Xiao-Dong Li, Shi-Qiang Yu, Jing-Hua Guo, Yan Zhang, and Da-Wei Du
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Materials science ,Renewable Energy, Sustainability and the Environment ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Silsesquioxane ,0104 chemical sciences ,Hydrogen storage ,chemistry.chemical_compound ,Fuel Technology ,Adsorption ,chemistry ,Volume (thermodynamics) ,Physical chemistry ,Molecule ,Gravimetric analysis ,Monte Carlo integration ,0210 nano-technology ,Helium - Abstract
With the aid of computer simulation, we have designed four covalent-organic frameworks based on tetrakis(4-aminophenyl)silsesquioxane (taps-COFs) and their hydrogen storage properties were predicted with grand canonical Monte Carlo (GCMC) simulation. The structural parameters and physical properties were investigated after the geometrical optimization. The accessible surface for H2 molecule (5564.68–6754.78 m2/g) were estimated using the numerical Monte Carlo integration and the pore volume (4.06–10.74 cm3/g) was evaluated by the amounts of the containable nonadsorbing helium molecules at low pressures and room temperature. GCMC simulation reveals that at 77 K, taps COF 1 has the highest gravimetric H2 adsorption capacity of 51.43 wt% and taps COF 3 possesses the highest volumetric H2 adsorption capacity of 58.51 g/L. Excitedly, at room temperature of 298 K, the gravimetric hydrogen adsorption capacities of taps COF 1 (8.58 wt%) and taps COF 2 (8.20 wt%) have exceeded the target (5.5 wt%) of onboard hydrogen storage system for 2025 set by the U.S Department of Energy.
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- 2019
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8. Room temperature ferromagnetism and fast ultraviolet photoresponse of inkjet-printed Mn-doped ZnO thin films
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Yan Wu, Rao, K.V., Voit, W., Tamaki, T., Jayakumar, O.D., Belova, L., Liu, Y.S., Glans, P.A., Chang, C.L., and Jing Hua Guo
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Ferromagnetism -- Analysis ,Ink-jet printers -- Usage ,Manganese -- Magnetic properties ,Manganese -- Electric properties ,Semiconductor doping -- Analysis ,Zinc oxide -- Magnetic properties ,Zinc oxide -- Electric properties ,Ink jet printer ,Business ,Electronics ,Electronics and electrical industries - Published
- 2010
9. Combined DFT and kinetic Monte Carlo study of a bridging-spillover mechanism on fluorine-decorated graphene
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Hongbo Wang, Gang Chen, Jinxiang Liu, Haiying Liu, and Jing-Hua Guo
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Materials science ,Hydrogen ,Graphene ,General Physics and Astronomy ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,Catalysis ,Adsorption ,chemistry ,law ,Chemical physics ,Fluorine ,Cluster (physics) ,Kinetic Monte Carlo ,Physical and Theoretical Chemistry ,0210 nano-technology ,Carbon - Abstract
In this work, combining first-principles calculations with kinetic Monte Carlo (KMC) simulations, we constructed an irregular carbon bridge on the graphene surface and explored the process of H migration from the Pt catalyst to carbon bridge, and further migration to the graphene surface. The calculated reaction diagrams show that the hydrogen atoms can easily migrate from the Pt cluster to the carbon bridge with a low barrier of 0.22-0.86 eV, and KMC simulations indicate that the migration reactions can take place at intermediate temperatures (91.9-329.5 K). Our research clarified the role of the carbon bridge: (1) the close combination of Pt clusters and carbon bridges reduces H2 adsorption enthalpy, which facilitates the spillover of H atoms from the Pt cluster to the carbon bridges and (2) the unsaturated carbon atoms on the carbon bridges have radical character and tend to bind radical H atoms. The subsequent study shows that the F atoms decorated on graphene can greatly reduce the migration barrier of H atoms from the carbon bridge to graphene. With F atoms decorated, the carbon atoms are in an electron-deficient state, which have a strong ability to bind the hydrogen atoms, and it promotes the migration of H atoms to the graphene surface. The migration barrier and reaction temperature are reduced to 0.72 eV and 279 K, respectively.
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- 2021
10. Novel joint catalytic properties of Fe and N co-doped graphene for CO oxidation
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Hongbo Wang, Xuedong Ou, Jinxiang Liu, Xike Wang, Gang Chen, and Jing-Hua Guo
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Materials science ,Graphene ,General Physics and Astronomy ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,Ion ,Bond length ,Crystallography ,law ,Vacancy defect ,Atom ,Molecule ,Density functional theory ,Physical and Theoretical Chemistry ,Bond energy ,0210 nano-technology - Abstract
Using density functional theory, we have performed detailed calculations of the joint catalytic activity of graphene co-doped with Fe and N atoms. The Fe atom can be located on single vacancy graphene and acts as the active site. Due to the strong attraction of the Fe ion, the O-O bond length of the O2 molecule is elongated, which decreases the bonding energy between the O atoms. The energy barrier of CO oxidization is 0.84 eV. When N atoms are doped into the graphene, the interactions between the Fe ions and O2 molecules are stronger, and the O-O bond lengths are elongated further, which makes the desorption of the quasi-CO2 molecule easier. The energy barriers are reduced to 0.62 eV, 0.49 eV, and 0.33 eV for graphene doped with one, two and three N atoms, respectively. The O atom remaining on the Fe ion can form a CO2 molecule with an additional CO molecule. The produced CO2 molecule can be released with a small or even zero energy barrier by adsorbing an O2 molecule. The adsorbed O2 molecule is then involved in the next reaction process, and the material can be used as a recycled catalyst.
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- 2020
11. Kaempferol Alleviates Oxidative Stress and Apoptosis Through Mitochondria-dependent Pathway During Lung Ischemia-Reperfusion Injury
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Rongsheng Wang, Zhaohui He, Jing-Hua Guo, Hongbo Li, Wenkai Yang, Chunli Yang, and Xiaogang Yang
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PGC-1α ,Mitochondrion ,medicine.disease_cause ,chemistry.chemical_compound ,SIRT1 ,medicine ,oxidative stress ,Pharmacology (medical) ,Viability assay ,lung ischemia-reperfusion injury ,Original Research ,Pharmacology ,kaempferol ,biology ,Cytochrome c ,lcsh:RM1-950 ,apoptosis ,medicine.disease ,Cell biology ,mitochondria ,lcsh:Therapeutics. Pharmacology ,chemistry ,Mitochondrial permeability transition pore ,Apoptosis ,biology.protein ,Kaempferol ,Reperfusion injury ,Oxidative stress - Abstract
In previous study, we reported that kaempferol ameliorates significantly lung ischemia-reperfusion injury (LIRI), and may be achieved by targeting the SIRT 1 pathway. This study further explored the anti-LIRI mechanism of kaempferol. In vitro, the rat alveolar epithelial cells L2 was cultured and subjected to anoxia/reoxygenation (A/R) insult. In vivo, SD rats were operated to establish LIRI model. The related indicators of oxidative stress and apoptosis in L2 cells and rats lung tissues were detected. Results showed that kaempferol pre-treatment significantly increased the cell viability, improved mitochondrial membrane potential, inhibited the opening of mitochondrial permeability transition pores, reduced the levels of oxidative stress and apoptosis, increased the expressions of Bcl-2 and mitochondrial cytochrome c, and decreased the expressions of Bax and cytoplasmic cytochrome c in L2 cells after A/R insult. In vivo, kaempferol improved the pathological injury, inhibited the levels of oxidative stress and apoptosis, increased the expressions of Bcl-2 and mitochondrial cytochrome c, and decreased the expressions of Bax and cytoplasmic cytochrome c in rats lung tissues after I/R. However, the aforementioned effects of kaempferol were significantly attenuated by the SIRT 1 inhibitor EX527 or the PGC-1α inhibitor SR-18292. What’s more, SR-18292 has not reversed the effect of kaempferol on increasing the protein activity of SIRT 1. Above results suggest that kaempferol ameliorates LIRI by improving mitochondrial function, reducing oxidative stress and inhibiting cell apoptosis. Its molecular mechanism of action includes the SIRT 1/PGC-1α/mitochondria signaling pathway.
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- 2020
12. Effects of glue-line thickness and manufacturing defects on the pull-out behavior of glued-in rods
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Abdelhamid Bouchaïr, Jing-Hua Guo, Bo-Han Xu, Institut Pascal (IP), and SIGMA Clermont (SIGMA Clermont)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)
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Materials science ,genetic structures ,Polymers and Plastics ,General Chemical Engineering ,Stiffness ,030206 dentistry ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Glue line ,Finite element method ,Rod ,Biomaterials ,03 medical and health sciences ,[SPI]Engineering Sciences [physics] ,[SPI.GCIV]Engineering Sciences [physics]/Civil Engineering ,0302 clinical medicine ,Brittleness ,Position (vector) ,medicine ,Adhesive ,medicine.symptom ,Composite material ,0210 nano-technology ,Control methods ,ComputingMilieux_MISCELLANEOUS - Abstract
Glued-in rods are offering to timber joints not only enhanced stiffness and high load capacity but also aesthetical appearance and good fire resistance. However, no consistent manufacturing process and quality control method is reported in the literature. It is necessary to estimate the effect of possible manufacturing defects on pull-out behavior of glued-in rods. This paper presents the experimental results on glued-in rods with two types of possible manufacturing defects on site: eccentric position of rod in hole and inclined setting of rod in hole. The effect of manufacturing defects was investigated on the samples with three different glue-line thicknesses. A finite element model considering the elastic behavior of materials with their measured elastic parameters and dimensions is proposed. It illustrates the evolution of the stress distribution in the connection zone and explains the observed brittle failure modes.
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- 2020
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13. The theoretical study of the bimetallic Ni/Pd, Ni/Pt and Pt/Pd catalysts for hydrogen spillover on penta-graphene
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Haiying Liu, Jing-Hua Guo, Shu-Juan Li, Xiao-Dong Li, Xinlu Cheng, and Gang Chen
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Materials science ,Renewable Energy, Sustainability and the Environment ,Energy Engineering and Power Technology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Bimetal ,Hydrogen storage ,Fuel Technology ,Adsorption ,Molecule ,Physical chemistry ,Hydrogen spillover ,0210 nano-technology ,Bimetallic strip ,HOMO/LUMO - Abstract
The catalytic property of the bimetallic Ni/Pd, Ni/Pt and Pt/Pd particles for hydrogen spillover on penta-graphene (PG) are studied by using the first-principles and kinetic Monte Carlo (KMC) calculations. The bimetallic Ni/Pd, Ni/Pt and Pt/Pd particles can be stably decorated on PG surface with binding energies in the range of 4.15–5.52 eV. The adsorption enthalpies of H2 molecules on bimetallic particles are in the range of −11.56–−15.35 kcal/mol. The H atom can migrate from the bimetallic particles to PG with the migration barriers range from 0.67 to 0.95 eV. The KMC simulations show that the hydrogen spillover reactions can occur at a suitable temperature (260–361 K), which meet DOE target for onboard hydrogen storage systems applied to light-duty vehicles. In the study, the highest occupied molecular orbital and electric field analysis shows that the bimetal mixing can reduce the hydrogen adsorption enthalpy, and thereby reduce the H migration barrier, which displays a synergistic effect for hydrogen spillover.
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- 2018
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14. Theoretical design of Li-doped ILCOF-1 for high H2 uptake at moderate temperature
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Jing-Hua Guo
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General Computer Science ,Hydrogen ,Chemistry ,Doping ,General Physics and Astronomy ,Thermodynamics ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Moderate temperature ,0104 chemical sciences ,Computational Mathematics ,Hydrogen storage ,Mechanics of Materials ,Computational chemistry ,Gravimetric analysis ,General Materials Science ,Density functional theory ,Kinetic Monte Carlo ,0210 nano-technology ,Covalent organic framework - Abstract
In this paper, we designed a good hydrogen storage material of Li-doped ILCOF-1 in theory. The first-principles studies show that the Li-doped ILCOF-1 has a high hydrogen storage capacity (the gravimetric and volumetric uptake are 7.26 wt% and 27.2 g/L, respectively). The 2020 U.S. Department of Energy (DOE) gravimetric target can be achieved. The kinetic Monte Carlo simulations are performed to predict the optimal condition for hydrogen storage and release. Based on the DOE limits, the optimal condition for hydrogen storage is at 250 K and 12 bar, and for hydrogen release is at 350 K and 0.5 bar.
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- 2018
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15. Pt4, Pd4, Ni4, and Ti4 catalyzed hydrogen spillover on penta-graphene for hydrogen storage: The first-principles and kinetic Monte Carlo study
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Jing-Hua Guo, Dan-Dan Liu, Xiao-Dong Li, Haiying Liu, and Gang Chen
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Materials science ,Renewable Energy, Sustainability and the Environment ,Penta-graphene ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Hydrogen storage ,Fuel Technology ,Adsorption ,Spillover effect ,chemistry ,Physical chemistry ,Kinetic Monte Carlo ,Hydrogen spillover ,0210 nano-technology ,Carbon - Abstract
Penta-graphene is a new 2D allotrope of carbon exclusively consists of pentagons in a planar sheet geometry. In this work, we explored that if it can be a substrate for hydrogen spillover. The density-functional theory (DFT) studies show that the H atom can stably adsorb on sp2 carbons. The saturation hydrogen storage density of penta-graphene is estimated to be 5.3 wt%. The Pt4, Pd4 Ni4, and Ti4 clusters are used as the catalyst for hydrogen spillover, and the migration barriers are 1.25, 1.07, 1.03 and 1.35 eV, respectively. The kinetic Monte Carlo simulations are performed to study the migration process for massive H atoms. The results show that the optimal reaction temperatures are 467, 405, 390, and 504 K for Pt4, Pd4, Ni4, and Ti4 catalyst, respectively. For Pd4 and Ni4 catalysts, the spillover reaction can occur at the appropriate temperature (355 and 340 K, respectively) for onboard hydrogen storage systems applied to light-duty vehicles.
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- 2018
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16. Theoretical Study of a Bridging-Spillover Mechanism in Covalent Organic Frameworks on Pt6 and Pt4 Cluster Models
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Xinlu Cheng, Jing-Hua Guo, Shu-Juan Li, and Gang Chen
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Bridging (networking) ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,General Energy ,chemistry ,Spillover effect ,Chemical physics ,Computational chemistry ,Mechanism (philosophy) ,Covalent bond ,Cluster (physics) ,Kinetic Monte Carlo ,Physical and Theoretical Chemistry ,Hydrogen spillover ,0210 nano-technology ,Carbon - Abstract
It is recognized that “the bridge-building technique remains an art”, due to unclear microscopic nature of the bridging-spillover mechanism. In this paper, a theoretical model of a carbon bridge is designed to reveal the bridging-spillover mechanism in covalent organic frameworks (COFs) by the first-principles calculations and kinetic Monte Carlo (KMC) simulations. It is found that the activation barrier of H migration from a Pt cluster to carbon bridge ranges from 0.23 to 1.05 eV, which is much lower than the direct migration from the Pt6 cluster to COF-8 (activation barrier of 2.1 eV). The bare carbon atoms on carbon bridges are mainly responsible for facilitating hydrogen spillover. KMC simulations display that H would not directly migrate from the Pt6 cluster to COF-8 unless elevating the temperature to 700 K, in contrast to that of lower temperature (88–360 K) for H migration from the Pt6 cluster to carbon bridges. In addition, the introduction of oxygen impurities can reduce the H migration barrier ...
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- 2016
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17. Quietness of circular RNA circ_0054633 alleviates the inflammation and proliferation in lipopolysaccharides-induced acute lung injury model through NF-κB signaling pathway
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Chunli Yang, Zhaohui He, Jing-Hua Guo, Hongbo Li, Xiaogang Yang, and Wenkai Yang
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Lipopolysaccharides ,Male ,0301 basic medicine ,Acute Lung Injury ,Apoptosis ,Inflammation ,Lung injury ,Biology ,Proinflammatory cytokine ,Rats, Sprague-Dawley ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Genetics ,medicine ,Animals ,Gene silencing ,Lung ,Cells, Cultured ,Cell Proliferation ,Tumor Necrosis Factor-alpha ,Interleukin-17 ,NF-kappa B ,Transcription Factor RelA ,Endothelial Cells ,RNA, Circular ,General Medicine ,Rats ,respiratory tract diseases ,030104 developmental biology ,Real-time polymerase chain reaction ,030220 oncology & carcinogenesis ,Cancer research ,Tumor necrosis factor alpha ,Signal transduction ,medicine.symptom - Abstract
Aim Acute lung injury (ALI) is the mild form of acute respiratory distress syndrome (ARDS) which is a common lung disease with a high incidence and mortality rate. Recent studies manifested that some circular RNAs were associated with ALI. In this study, we aimed to uncover the effect of circular RNA circ_0054633 on ALI initiation and progression and proposed a new mechanism related to ALI. Methods The lipopolysaccharides (LPS)-induced acute lung injury model were build both in vivo of rat and in vitro of primary murine pulmonary microvascular endothelial cells (MPVECs). Hematoxylin and eosin (H&E) was employed to observe the tissue morphology and estimate the degree of lung damage. We used real-time quantitative polymerase chain reaction (RT-qPCR) to measure the expression level of circ_0054633. The expression levels of inflammatory cytokines IL-17A and tumor necrosis factor-α (TNF-α) were detected by ELISA. The effects of circ_0054633 on MPVECs proliferation and apoptosis were detected with the help of CCK-8 and apoptosis assay, separately. The expression level of NF-κB p65 protein was measured by Western blot. Results circ_0054633, IL-17A, TNF-α and NF-κB p65 were all overexpressed in LPS-treated rat and MPVECs, and LPS enhanced the proliferation and apoptosis of MPVECs. While circ_0054633 silencing reversed the above promotion effects of LPS on IL-17A, TNF-α expression and MPVECs proliferation and apoptosis. Conclusions Quietness of circ_0054633 alleviated LPS-induced ALI via NF-κB signaling pathway, implicating circ_0054633 may be a potential biomarker for diagnose and therapy of ALI.
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- 2021
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18. Molecular insights into the kinetic hydrate inhibition performance of Poly(N-vinyl lactam) polymers
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Jing-Hua Guo, Jinxiang Liu, Jun Zhang, Youguo Yan, Hongbo Wang, Gang Chen, and Jie Zhong
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chemistry.chemical_classification ,Chemistry ,020209 energy ,technology, industry, and agriculture ,Caprolactam ,Energy Engineering and Power Technology ,macromolecular substances ,02 engineering and technology ,Polymer ,Geotechnical Engineering and Engineering Geology ,Kinetic energy ,Ring size ,chemistry.chemical_compound ,Fuel Technology ,Adsorption ,020401 chemical engineering ,Polymer chemistry ,0202 electrical engineering, electronic engineering, information engineering ,Lactam ,Reactivity (chemistry) ,0204 chemical engineering ,Hydrate - Abstract
The inhibition mechanism and the inhibition performance of four typical kinetic hydrate inhibitors (KHIs), poly(N-vinyl pyrrolidone) (PVP), poly(N-vinyl piperidone) (PVPip), poly(N-vinyl caprolactam) (PVCap) and poly(N-vinyl azacyclooctanone) (PVAco), have been studied using first-principle calculations and simulations. The results show that the inhibitors can disturb the local water structure, but also can adsorb onto the open hydrate cage, exhibiting the features of both the perturbation-inhibition and the adsorption-inhibition. By analyzing the molecular reactivity, KHI-water interactions, and adsorption ability of KHIs, it is found that the inhibition performance of the inhibitor increases with the increase of the lactam ring size, that is, PVP
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- 2020
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19. Combined pretreatment serum CA19-9 and neutrophil-to-lymphocyte ratio as a potential prognostic factor in metastatic pancreatic cancer patients
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Shi-Feng Lian, Jing-Hua Guo, Mingqiu Chen, Benhua Xu, and Jianyuan Song
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0301 basic medicine ,Male ,medicine.medical_specialty ,Multivariate analysis ,endocrine system diseases ,CA-19-9 Antigen ,Neutrophils ,Observational Study ,Kaplan-Meier Estimate ,Gastroenterology ,03 medical and health sciences ,Leukocyte Count ,0302 clinical medicine ,metastatic pancreatic cancer ,neutrophil-to-lymphocyte ratio ,Internal medicine ,Metastatic pancreatic cancer ,Biomarkers, Tumor ,Medicine ,Humans ,Lymphocyte Count ,Lymphocytes ,Neutrophil to lymphocyte ratio ,prognostic factor ,Aged ,Proportional Hazards Models ,Retrospective Studies ,Receiver operating characteristic ,business.industry ,Proportional hazards model ,fungi ,Area under the curve ,Retrospective cohort study ,General Medicine ,Middle Aged ,Prognosis ,CA19-9 ,digestive system diseases ,Pancreatic Neoplasms ,030104 developmental biology ,030220 oncology & carcinogenesis ,Area Under Curve ,Multivariate Analysis ,Regression Analysis ,Female ,business ,Research Article - Abstract
The aim of this study was to explore the role of combined pretreatment serum carbohydrate antigen 19-9 (CA19-9) and neutrophil-to-lymphocyte ratio (NLR) as potential prognostic factors in metastatic pancreatic cancer patients. We investigated pretreatment serum CA19-9 and NLR in 59 metastatic pancreatic cancer patients, determined the patients’ thresholds by receiver operating characteristic curve analysis, and assessed their prognostic values by Kaplan–Meier curve and Cox regression models. Results of multivariate analysis showed high CA19-9, high NLR, and high score (the scoring system of CA19-9 and NLR) were significantly correlated with overall survival. Area under the curve of the scoring system was higher than that of CA19-9 or NLR. Combined pretreatment serum CA19-9 and NLR is a better prognostic biomarker of metastatic pancreatic cancer patients than CA19-9 or NLR alone.
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- 2018
20. Spin transport of dibenzotetraaza[14]annulene complexes with first row transition metals
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Gang Chen, Peini Zhao, Qiu-Hua Wu, Yan Su, Li Shuna, and Jing-Hua Guo
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Condensed matter physics ,Chemistry ,General Chemical Engineering ,Non-equilibrium thermodynamics ,Anchoring ,Biasing ,General Chemistry ,Annulene ,symbols.namesake ,Transition metal ,Electrode ,symbols ,Condensed Matter::Strongly Correlated Electrons ,Density functional theory ,Hamiltonian (quantum mechanics) - Abstract
Based on spin-polarized first-principles density functional theory in conjunction with the nonequilibrium Green's function method, the spin transport properties of transition metal (TM)–dibenzotetraaza[14]annulene (DBTAA) complexes (TM = Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) sandwiched between two Au electrodes are investigated. The results show that Fe– and Co–DBTAA can display perfect spin filtering behavior in a wide bias voltage region. Moreover, it is found that the connected position of anchoring groups on the complexes affect significantly the spin filtering efficiency. The observed spin filtering behavior is explained by the spin-resolved transmission spectrum and molecular projected self-consistent Hamiltonian state analyses.
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- 2015
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21. Design of 3D 1,3,5,7-tetraphenyladamantane-based covalent organic frameworks as hydrogen storage materials
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Xinlu Cheng, Xiu-Ying Liu, Hong Zhang, Xiao-Dong Li, and Jing-Hua Guo
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Hydrogen ,Chemistry ,General Chemical Engineering ,chemistry.chemical_element ,General Chemistry ,Accessible surface area ,Hydrogen storage ,Adsorption ,Chemical engineering ,Gravimetric analysis ,Organic chemistry ,Porosity ,Covalent organic framework ,Bar (unit) - Abstract
A new type of 1,3,5,7-tetraphenyladamantane-based covalent organic framework (adm-COF) was designed under the ctn and bor net topology with the method of molecular mechanics. The computed results reveal that all four designed adm-COFs exhibit extremely high porosity (86–95%) and large H2 accessible surface area (5967–6709 m2 g−1). The grand canonical Monte Carlo method was employed to simulate the adsorption isotherms of H2 gas in these adm-COFs at 77 K and 298 K. The simulated results indicate that, at 77 K and 100 bar, adm-COF-4 has the highest gravimetric H2 adsorption capacity of 38.36 wt%, while adm-COF-1 has the highest volumetric H2 adsorption capacity of 60.71 g L−1. Impressively, the gravimetric H2 adsorption capacity of adm-COF-1 can reach up to 5.81 wt% under 100 bar at room temperature, which is very close to the criterion of 6 wt% for the practical application of hydrogen at room temperature set by the U.S. Department of Energy. In addition, possible schemes for synthesizing these adm-COFs have been proposed.
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- 2014
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22. Preparation and Stability Studies of a Desulfurizer Loaded on Porous Silica Gel
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Jing Hua Guo, Qi Su, Jin Xu, Wei Xu, Y.Y. Fang, and Meng Long Lai
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Flue gas ,chemistry.chemical_compound ,chemistry ,Silica gel ,Vapor pressure ,Ionic liquid ,Inorganic chemistry ,General Engineering ,Thermal stability ,Particle size ,Porosity ,Sulfur dioxide - Abstract
A novel ionic liquid 1,1,3,3-tetramethylguanidinium lactate (TMGL) has been prepared. And the stability of ionic liquid was determined at different temperatures and pressures, which shows extremely low vapor pressure and high thermal stability. TMGL was immobilized by adjusting the feed ratio (TMGL/SiO2) and particle size, the concentration of 0.90% sulfur dioxide gas passed into a certain amount of the loaded ionic liquid TMGL-SiO2, quickly reduced to less than 0.05%, the concentration was measured by a BRUKER Infra-red Spectrometer. This ionic liquid has potential applications in flue gas desulphuration (FGD).
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- 2014
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23. Ca2+- and Mg2+-doped covalent organic frameworks exhibiting high hydrogen and acetylene storage
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Hong Zhang, Jing-Hua Guo, Min Gong, and Xinlu Cheng
- Subjects
Hydrogen ,Chemistry ,Binding energy ,Inorganic chemistry ,chemistry.chemical_element ,Condensed Matter Physics ,chemistry.chemical_compound ,Hydrogen storage ,Adsorption ,Acetylene ,Covalent bond ,Computational chemistry ,Molecule ,Gravimetric analysis ,Physical and Theoretical Chemistry - Abstract
A multiscale theoretical investigation has been performed to study the hydrogen and acetylene storage in Ca2+- and Mg2+-doped COFs (COF-105 and COF-108). The first-principles calculations show that the Ca2+ and Mg2+ can be immobilized at the COFs surfaces, and the doped Ca and Mg cations can adsorb five H2 molecules and three C2H2 molecules with ideal binding energies. The Grand Canonical Monte Carlo (GCMC) simulations were carried out to obtain the hydrogen and acetylene uptakes of Ca2+- and Mg2+-doped COFs at room temperature in the different pressure ranges. Our results demonstrate that, at T = 298 K and p = 100 bar, the total gravimetric uptakes of H2 in Ca2+-doped COF-105 and COF-108 reach 6.78 and 6.54 wt%, respectively, and a higher uptakes of 7.14 and 7.27 wt% have been reached for Mg2+-doped COF-105 and COF-108, respectively. At T = 298 K and p = 1 bar, the acetylene uptakes of Ca2+-doped COF-105, Ca2+-doped COF-108, Mg2+-doped COF-105, and Mg2+-doped COF-108 are 406.42, 366.24, 308.07, and 319.88 cm3/g (corresponding to the excess uptakes of 358.37, 316.38, 236.7109, and 245.42 cm3/g), respectively. The Ca2+-doped COF-105 displays a highest acetylene storage capacity among all materials reported. The Ca2+- and Mg2+-doped COFs can be very practical hydrogen or acetylene storage medium in the future.
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- 2012
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24. Multiscale Study of Hydrogen Adsorption, Diffusion, and Desorption on Li-Doped Phthalocyanine Covalent Organic Frameworks
- Author
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Hong Zhang, Zhi-Pan Liu, Xinlu Cheng, and Jing-Hua Guo
- Subjects
Binding energy ,Inorganic chemistry ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,Hydrogen storage ,General Energy ,Adsorption ,chemistry ,Desorption ,Formula unit ,Phthalocyanine ,Molecule ,Physical chemistry ,Kinetic Monte Carlo ,Physical and Theoretical Chemistry - Abstract
In this paper, we performed a multiscale study on the hydrogen storage capacity of Li-doped phthalocyanine covalent organic frameworks (Li-doped Pc-PBBA COF). We combine the first-principles studies of hydrogen adsorption and migration energies with the kinetic Monte Carlo simulations of hydrogen adsorption, diffusion, and desorption processes in Li-doped Pc-PBBA COF. The first-principles calculations revealed that the Li atoms can be doped on the surface of the channel of Pc-PBBA COF with a binding energy of 1.08 eV. Each Li cation can bind three H2 molecules with an average adsorption energy of 0.11 eV. At most, 24 H2 molecules can be adsorbed in one formula unit, corresponding to a maximum of gravimetric density of 5.3 wt % and volumetric uptake of 45.2 g/L. The diffusion barriers of H2 between different Li-adsorption sites are in the range 0.027–0.053 eV. The KMC simulations have predicted that the optimum conditions of hydrogen storage for Li-doped Pc-PBBA COF are at T = 250 K and P = 100 bar, with a...
- Published
- 2012
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25. The effect of electric field on hydrogen storage for B/C/N sheets
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Hong Zhang and Jing-Hua Guo
- Subjects
Hydrogen storage ,Adsorption ,Chemistry ,Electric field ,Analytical chemistry ,Physical and Theoretical Chemistry ,Atomic physics ,Condensed Matter Physics ,Layer (electronics) ,Adsorption energy ,Intensity (heat transfer) - Abstract
Using first-principles calculations, we investigate the adsorption behaviors of H2 in B/C/N sheets (including BCN, BC2N, and BC3N) and discuss the effect of external electric fields on H2 adsorbed for BCN and BC2N sheets. For a single H2 adsorbed on BCN and BC2N sheets, the adsorption energy increases dramatically with the electric field intensity increasing, and the maximum adsorption energy can reach 0.55 eV in the electric field of F = 0.050 a.u. and one layer H2 can adsorb on BCN and BC2N sheets, corresponding to the maximum hydrogen storage capacity of 5.1 wt%. The average adsorption energy calculated larger than that of in the field-free case.
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- 2011
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26. The effect of ionization and CH3 ligand for hydrogen storage in Co- and Ni-based organometallic compounds
- Author
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Yoshiyuki Miyamoto, Xinlu Cheng, Jing-Hua Guo, and Hong Zhang
- Subjects
Chemistry ,Ligand ,Binding energy ,Condensed Matter Physics ,Ring (chemistry) ,Atomic and Molecular Physics, and Optics ,Crystallography ,Hydrogen storage ,Adsorption ,Transition metal ,Organic chemistry ,Molecule ,Physical and Theoretical Chemistry ,Group 2 organometallic chemistry - Abstract
Maximum capacities of the hydrogen storage in organometallic compounds consisting of Co and Ni atoms bound to CmHm ring (m = 4, 5; capped type) were, respectively, found as 3.48 and 3.49 wt % (Guo et al., Struct Chem, 2009, 20, 1107). Here, we extend this study to structures having a transition metal (TM) inserted in CmHm ring (inserted type), having TM located on either a C4H or a C5H molecule, and the CH3 ligand bound to the organometallic compounds. We find that for the CoC4H4 and NiC4H4 complexes, the capped types are 1.39 eV and 1.41 eV higher in energy than the inserted types, respectively, while the ground states for CoC5H5 and NiC5H5 complexes are found to be the capped type, which are lower than the inserted types, respectively, by 1.27 eV and 1.31 eV. The maximum capacity of hydrogen storage reached 5.13 wt % for both of CoC4H(H2)3 complex and the inserted-type CoC4H4(H2)3 complex with a reasonable binding energy (0.3–1.0 eV per H2). The positively charged C4H4 and C5H5 molecules do not only improve the capacity of hydrogen storage but also make all H2 adsorbing in molecular form and keep the adsorption energy in an ideal range. After adding the CH3 ligand to the compounds, the average adsorption energy of H2 decreased to an ideal range 0.61–0.94 eV per H2 and the stability of the compounds is also improved. Finally, we analyze the HOMO–LUMO gaps and display the kinetic stability when H2 was added to organometallic compounds. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
- Published
- 2010
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27. Hydrogen binding property of Co- and Ni-based organometallic compounds
- Author
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Hong Zhang, Jing-Hua Guo, and Wei-Dong Wu
- Subjects
Hydrogen ,Binding energy ,chemistry.chemical_element ,Isolobal principle ,Condensed Matter Physics ,Hydrogen storage ,Adsorption ,chemistry ,Computational chemistry ,Physical chemistry ,Molecular orbital ,Density functional theory ,Physical and Theoretical Chemistry ,Group 2 organometallic chemistry - Abstract
The binding property of hydrogen on organometallic compounds consisting of Co, and Ni transition metal atoms bound to C m H m rings (m = 4, 5) is studied through density functional theory calculation. CoC m H m and NiC m H m complexes can store up to 3.49 wt% hydrogen with an average binding energy of about 1.3 eV. The adsorption characteristics of hydrogen to organometallic compounds are investigated by analyzing vibrational spectra of CoC4H4(H2) n and NiC4H4(H2) n (n = 0, 1, 2). The kinetic stability of these hydrogen-covered organometallic complexes is assured by analyzing the energy gap between the highest occupied molecular orbitals and the lowest unoccupied molecular orbitals. It is also discussed the application of 18-electron rule in predicting maximum number of hydrogen molecules that could be adsorbed by these organometallic compounds.
- Published
- 2009
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28. Vascular Bundle Implantation into Bone for Aseptic Necrosis of the Lunate
- Author
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Jing-hua Guo
- Subjects
Adult ,Male ,Microsurgery ,medicine.medical_specialty ,Bone disease ,Wrist ,Veins ,Postoperative Complications ,Bone Density ,Humans ,Medicine ,Cyst ,Lunate Bone ,Vein ,Aseptic necrosis ,business.industry ,Osteonecrosis ,Lunate bone ,Arteries ,Anatomy ,medicine.disease ,Surgery ,Occupational Diseases ,Radiography ,Lunate ,medicine.anatomical_structure ,Female ,business ,Follow-Up Studies ,Artery - Abstract
Since April 1986, implantation of a vascular bundle containing the ramus carpeus dorsalis of the interosseal anterior artery and vein into the lunate has been undertaken for aseptic necrosis of the lunate bone. A series of 11 cases were performed in East-South Hospital with satisfactory results. The average follow-up period was 36 months. A series of follow-up roentgenograms reveal that necrosis of the lunate bone is being continuously repaired. Fourteen months postoperative, the following results are obtained: (1) the sclerosis of the lunate bone has completely disappeared on the roentgenograms, (2) the architecture and density of the lunate bone have returned to normal on the roentgenograms, (3) technically colorized X-ray films show that lunate bone density decreases after the operation (the decreasing range is 20 to 44 Gray scale [mean, 30.3 +/- 2.4 Gray scale]) and that the cyst formations on the lunate bone have completely disappeared postoperatively, and (4) pain in the affected wrists disappeared and patients have returned to their former work, including manual labor. The necrotized lunate bones are healed. Anatomic study shows that the presence of the ramus carpeus dorsalis of the interosseal anterior artery and vein on the wrist is 100%, and the structure as well as location of the ramus carpeus dorsalis has little anatomic variation and is long enough to be transplanted into the lunate bone.
- Published
- 1996
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29. [Optical parameters of Er3+ in Er3+ : YVO4]
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Ying, Chen, Xiao-bo, Chen, Luan, Chen, Da-he, Liu, Zeng-fu, Song, Yong-liang, Li, Song, Li, Yong-zhi, Zeng, Zheng-long, Wu, Chun-lin, Zhang, Ya-fei, Wang, and Jing-hua, Guo
- Abstract
In the present paper the authors firstly measured the absorption spectra of Er3+ in the sample Er3+ : YVO4 (0.5%), then calculated the intensity parameters are calculated by using the Judd-Ofelt theory. After that the authors dealed with some predicted spectroscopic parameters, such as the oscillator strength, spontaneous radiative transition rate, branching ratio and integrated emission cross section. And Er : YVO4 crystal application value has been analyzed with the optical parameters. Especially there are large oscillator strengths and large integrated emission cross sections in the transitions of 4 I1/2 --4 I15/2, 2 H11/2 --4I15/2, 4S3/2 --4 I15/2, and 4F9/2 --4 I15/2. So, they are more worth of attention. Moreover, by comparing the Er-doped yttrium vanadate crystal and other Er-doped crystal optical properties, the authors can see the advantages of YVO4 as laser crystal. Finally, the authors discussed the splitting of the energy levels of Er3+ in the crystal YVO4 based on the group theory.
- Published
- 2010
30. Combined pretreatment serum CA19-9 and neutrophil-to-lymphocyte ratio as a potential prognostic factor in metastatic pancreatic cancer patients.
- Author
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Jian-Yuan Song, Ming-Qiu Chen, Jing-Hua Guo, Shi-Feng Lian, and Ben-Hua Xu
- Published
- 2018
- Full Text
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31. [Effect of clozapine and risperidone on serum cytokine levels in patients with first-episode paranoid schizophrenia]
- Author
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Lu-xian, Lü, Su-qin, Guo, Wei, Chen, Qiang, Li, Jun, Cheng, and Jing-hua, Guo
- Subjects
Adult ,Male ,Schizophrenia, Paranoid ,Adolescent ,Interleukin-6 ,Tumor Necrosis Factor-alpha ,Interleukin-18 ,Risperidone ,Cytokines ,Humans ,Interleukin-2 ,Female ,Clozapine ,Antipsychotic Agents - Abstract
To study the effects of clozapine and risperidone on serum cytokine levels in patients with first-episode paranoid schizophrenia, and explore the role of the cytokines in the psychopathological basis of the illness.Fifty-eight patients with first-episode paranoid schizophrenia were treated with either clozapine or risperidone, and before and at the end of the 4th, 8th weeks and 6th months after the medication respectively, the serum levels of interleukin (IL)-6, 2, 18,and tumor necrosis factor (TNF)alpha were measured with enzyme-linked immunosorbent assay (ELISA). The Positive and Negative Syndrome Scale (PANSS) was used to evaluate the psychotic symptoms.In patients treated with risperidone, the levels of serum IL-6 and IL-2 after 4 weeks, TNFalpha after 8 weeks, and IL-18 after 6 months were all significantly lowered in comparison with the pretreatment levels (P0.01 or 0.05). In clozapine group, the levels of IL-2 after 4 weeks and IL-6 and IL-18 after 6 months were lowered significantly (P0.01 or 0.05). Before the medication, serum IL-6 level was positively correlated with Positive Syndrome scores (r=0.386, P0.01), IL-2 with the total score and Positive Syndrome scores (r=0.338, 0.305; P0.01, 0.05), and TNFalpha with the total score (r=0.283, P0.05). The changes of IL-2 and IL-6 after 8 weeks was positively correlated with the change of Positive Syndrome scores (r=0.268, 0.375; P0.05, 0.01). Six months after the medication, the change in IL-6 and TNFalpha levels was positively correlated with the change of total score (r=0.365, 0.362; P0.05). Before treatment, IL-6 was positively correlated with IL-2 levels (r=0.356, P0.01), and TNFalpha with IL-18 levels (r=0.291, P0.05). TNFalpha was positively correlated with IL-6 levels (r=0.332, P0.01) 8 weeks after the medication. The changes in IL-6 was positively correlated with the those in IL-2 levels 6 months after the medication (r=0.391, P0.05).Clozapine and risperidone have similar immunosuppression actions and may affect serum IL-6 levels in patients with paranoid schizophrenia, in the psychopathology of which the cytokines play their roles of various importance.
- Published
- 2004
32. Unraveling the Origin of Visible Light Capture by Core-Shell TiO2 Nanotubes.
- Author
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Jun Li, Chang-Hai Liu, Xia Li, Zhi-Qiang Wang, Yu-Cheng Shao, Sui-Dong Wang, Xue-Liang Sun, Way-Faung Pong, Jing-Hua Guo, and Tsun-Kong Sham
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- 2016
- Full Text
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33. Multiphoton near-infrared quantum cutting luminescence phenomena of Tm^3+ ion in (Y_1-xTm_x)_3Al_5O_12 powder phosphor
- Author
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Yongliang Li, Gregory J. Salamo, Yan Gao, Quanlin Liu, Guo-Jian Yang, Xiaobo Chen, Xian-Lin Ding, and Jing-hua Guo
- Subjects
Spectroscopy, Near-Infrared ,Materials science ,Photoluminescence ,business.industry ,Phosphor ,Fluorescence ,Atomic and Molecular Physics, and Optics ,Fluorescence spectroscopy ,Ion ,Microscopy, Fluorescence, Multiphoton ,Optics ,Thulium ,Luminescent Measurements ,Materials Testing ,X-ray crystallography ,Quantum Theory ,Emission spectrum ,Powders ,business ,Luminescence - Abstract
In the present study, the multiphoton near-infrared downconversion quantum cutting luminescence phenomena of Tm3+ ion in (Y(1-x)Tm(x))(3)Al(5)O(12) powder phosphor, which is currently a hot research topic throughout the world, is reported. The x-ray diffraction spectra, the visible to near-infrared excitation and emission spectra, and fluorescence lifetimes are measured. It is found that Tm:YAG powder phosphor has intense two-photon quantum cutting luminescence, and, for the first time, it is found that Tm:YAG powder phosphor has strong four-photon near-infrared quantum cutting luminescence of 1788 nm (3)F4 → (3)H6 fluorescence of Tm(3+) ion. It is also found that the theoretical up-limit of four-photon near-infrared quantum cutting efficiency is about 282.12%, which results from both the {(1)D2 → (3)F2, (3)H6 → (3)H4} and {(3)H4 → (3)F4, (3)H6 → (3)F4} cross-energy transfers.
- Published
- 2013
- Full Text
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34. New Li-doped fullerene-intercalated phthalocyanine covalent organic frameworks designed for hydrogen storage
- Author
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Jing-Hua Guo, Yoshiyuki Miyamoto, and Hong Zhang
- Subjects
Fullerene ,Hydrogen ,General Physics and Astronomy ,chemistry.chemical_element ,chemistry.chemical_compound ,Hydrogen storage ,Molecular dynamics ,chemistry ,Covalent bond ,Phthalocyanine ,Physical chemistry ,Organic chemistry ,Gravimetric analysis ,Density functional theory ,Physical and Theoretical Chemistry - Abstract
Applying density functional theory (DFT) calculations, we have designed fullerenes (C20, C24, C26, C28, C30, C36, C60 and C70) intercalated phthalocyanine covalent organic frameworks (Cn-Pc-PBBA COFs). First principles molecular dynamics (MD) simulations showed that the structures of Cn-Pc-PBBA COFs are stable at room temperature and even at higher temperature (500 K). The interlayer distance of Pc-PBBA COF has been expanded to 7.48-13.25 Å by the intercalated fullerenes, and the pore volume and surface area were enlarged by 2.3-3.1 and 2.0-2.6 times, respectively. The grand canonical Monte Carlo (GCMC) simulations show that our designed Cn-Pc-PBBA COFs exhibit a superior hydrogen storage capability: at 77 K and P = 100 bar, the hydrogen gravimetric and volumetric uptakes reach 9.4-12 wt% and 48.1-52.2 g L(-1), respectively. To meet the requirement for practical application in hydrogen storage, we use the Li-doping method to modify the hydrogen storage performance of Cn-Pc-PBBA COFs. Our results show that the Li atoms can stably locate on the surface of C30-, C36, C60 and C70-Pc-PBBA COFs. At T = 298 K and P = 100 bar, for these four Li-doped Cn-Pc-PBBA COFs, the gravimetric and volumetric uptakes of H2 reach 4.2 wt% and 18.2 g L(-1), respectively.
- Published
- 2013
- Full Text
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35. Hydrogen spillover mechanism on covalent organic frameworks as investigated by ab initio density functional calculation
- Author
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Yongjian Tang, Xinlu Cheng, Jing-Hua Guo, and Hong Zhang
- Subjects
Hydrogen ,Chemistry ,Ab initio ,General Physics and Astronomy ,chemistry.chemical_element ,Bond length ,Hydrogen storage ,Computational chemistry ,Chemisorption ,Physical chemistry ,Molecule ,Density functional theory ,Physical and Theoretical Chemistry ,Hydrogen spillover - Abstract
The hydrogen spillover mechanism, including the H chemisorption, diffusion, and H(2) associative desorption on the surface of COFs and H atoms migration from metal catalyst to COFs, have been studied via density functional theory (DFT) calculation. The results described herein show that each sp(2) C atom on COFs' surface can adsorb one H atom with the bond length d(C-H) between 1.11 and 1.14 Å, and the up-down arrangement of the adsorbed H atoms is the most stable configuration. By counting the chemisorption binding sites for these COFs, we can predict the saturation storage densities. High hydrogen storage densities show that the gravimetric uptakes of COFs are in the range of 5.13-6.06 wt%. The CI-NEB calculations reveal that one H atom diffusing along the C-C path on HHTP surface should overcome the 1.41-2.16 eV energy barrier. We chose tetrahedral Pt(4) cluster and HHTP as the representative catalyst and substrate, respectively, to study the H migration from metal cluster to COFs. At most, two H atoms can migrate from Pt(4) cluster to HHTP substrate. The migration reaction is an endothermic process, undergoing an activation barrier of 1.87 eV and 0.57 eV for the first and second H migration process, respectively. Three types of H(2) associative desorption from hydrogenated COFs were studied: (I) the two H adatoms recombining to one H(2) molecule with a recombination barrier of 4.28 eV, (II) the abstraction of adsorbed H atoms by gas-phase hydrogen atoms through ER type recombination reactions with a recombination barrier of 1.05 eV, (III) the H(2) desorption through the reverse spillover mechanism with an energy barrier of 2.90 eV.
- Published
- 2013
- Full Text
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36. Hydrogen binding property of Co- and Ni-based organometallic compounds.
- Author
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Jing-Hua Guo, Wei-Dong Wu, and Hong Zhang
- Subjects
HYDROGEN bonding ,ORGANOMETALLIC compounds ,VIBRATIONAL spectra ,CHEMICAL kinetics ,COBALT compounds ,NICKEL compounds ,DENSITY functionals ,BINDING energy - Abstract
Abstract The binding property of hydrogen on organometallic compounds consisting of Co, and Ni transition metal atoms bound to C m H m rings (m = 4, 5) is studied through density functional theory calculation. CoC m H m and NiC m H m complexes can store up to 3.49 wt% hydrogen with an average binding energy of about 1.3 eV. The adsorption characteristics of hydrogen to organometallic compounds are investigated by analyzing vibrational spectra of CoC4H4(H2) n and NiC4H4(H2) n (n = 0, 1, 2). The kinetic stability of these hydrogen-covered organometallic complexes is assured by analyzing the energy gap between the highest occupied molecular orbitals and the lowest unoccupied molecular orbitals. It is also discussed the application of 18-electron rule in predicting maximum number of hydrogen molecules that could be adsorbed by these organometallic compounds. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
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