15 results on '"Cao, Chi"'
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2. Zero-dimensional hybrid zinc halide scintillators with efficient blue light emission for X-ray imaging
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Cheng, Haiming, Hu, Xudong, Cao, Chi, Li, Xiaoming, Xie, Renguo, Wang, Dayang, Yang, Wensheng, and Zhang, Ying
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- 2023
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3. Improvement in the age-hardening response of Mg–7Sn alloy by compressive stress-assisted aging
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Jiang, Jing, Tong, Lin, Xu, Zuocheng, Bi, Guangli, Cao, Chi, Li, Yuandong, Chen, Tijun, Fu, Wei, and Fang, Daqing
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- 2023
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4. Fabrication of 0D/2D TiO2 Nanodots/g-C3N4 S-scheme heterojunction photocatalyst for efficient photocatalytic overall water splitting
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Jiang, Yabin, Sun, Zongzhao, Chen, Qianwen, Cao, Chi, Zhao, Yun, Yang, Wensheng, Zeng, Lei, and Huang, Limin
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- 2022
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5. A facile method to introduce a donor-acceptor system into polymeric carbon nitride for efficient photocatalytic overall water splitting.
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Jiang, Yabin, Cao, Chi, Tan, Yueyang, Chen, Qianwen, Zeng, Lei, Yang, Wensheng, Sun, Zongzhao, and Huang, Limin
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NITRIDES ,FRONTIER orbitals ,X-ray photoelectron spectroscopy ,SOLAR cells - Abstract
• A new D -A structured polymeric carbon nitride (COCNT) was prepared based on the C, O-containing segment as a donor and the heptazine part as an acceptor. • The D -A systems of COCNT optimize the optical absorption and bandgap structures. • The spatial separation of charge in D -A systems enhances the photogenerated carrier separation and transfer, improving photocatalytic hydrogen production. • COCNT also shows efficient photocatalytic overall water splitting. It is a prospective strategy to produce sustainable energy by photocatalytic overall water splitting (POWS). This work aims to develop a simple method for integrating a donor-acceptor system into polymeric carbon nitride (PCN) structure, which could accelerate the charge separation significantly. In the as-prepared photocatalyst (COCNT), carbon and oxygen were successfully incorporated into the framework of PCN, and the chemical environment of C and O was well probed by X-ray absorption near-edge structure (XANES) and X-ray photoelectron spectroscopy (XPS). It showed that the C-containing and O-containing segments of COCNT played the role of a donor, while the heptazine part played the role of an acceptor. In addition, Density-functional-theory (DFT) calculations confirmed the spatial split of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) for promoting charge separation. Impressively, COCNT could efficiently split pure water to generate hydrogen and oxygen. And, the photocatalytic hydrogen evolution rate over COCNT (1550.9 µmol g
–1 h–1 ) is about 17-fold higher than that of PCN. Finally, we proposed a possible photocatalytic mechanism to explain the above results. [ABSTRACT FROM AUTHOR]- Published
- 2023
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6. Accumulation of localized charge on the surface of polymeric carbon nitride boosts the photocatalytic activity.
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Jiang, Yabin, Zeng, Lei, Cao, Chi, Yang, Wensheng, and Huang, Limin
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CHARGE carriers ,PHOTOCATALYSTS ,NITRIDES ,SURFACE charges ,SURFACE charging ,CHARGE carrier mobility ,CHARGE transfer - Abstract
• The in-planar directional charge transfer of polymeric C 3 N 4 can be realized by surface modification with ethylenediamine. • The increased -NH 2 groups induced the generation of midgap states and accumulation of electrons. • The modified C 3 N 4 exhibits excellent photocatalytic activities for hydrogen evolution and MO degradation. The random mobility of charge carriers is a main factor causing the low photocatalytic efficiency of g-C 3 N 4. Thus, the controllable migration of charge carriers is a rational strategy to suppress the charge recombination and facilitate charge separation. Herein, an ethylenediamine modified g-C 3 N 4 displays improved photocatalytic activity. The excellent charge separation efficiency is confirmed to be a key factor for the enhancement. The TEM observation after photo-depositing Pt nanoparticles and DFT calculations verify the accumulation of electrons on some areas of g-C 3 N 4 surface. The increased -NH 2 groups significantly tune the electronic structure of g-C 3 N 4 after the modification. The generation of midgap states also affects the charge separation. Our reports provide a simple method to manage the migration of charge carriers and enable electrons directional transfer, which suppresses the recombination and improves the photocatalytic activity. [ABSTRACT FROM AUTHOR]
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- 2022
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7. Research on multi-scale failure mechanism of gradient nanostructured 316L steel under strain-controlled fatigue at 650 °C.
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Mao, Jianfeng, Cao, Chi, Yang, Jiadong, Hua, Mengda, Cai, Youquan, Wang, Weigang, and Zhong, Fengping
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STEEL fatigue , *MATERIAL fatigue , *FATIGUE limit , *STRAINS & stresses (Mechanics) , *FATIGUE cracks - Abstract
• GNS layer induced by SMRT enhanced the strength-ductility synergy of 316L steel. • Gradient microstructure effectively inhibits strain localization during deformation. • SMRT 316L displays phase transformation and cyclic softening under fatigue at 650 ℃. • Fatigue life is well predicted by CPFE model with plastic-slip-based indicator. • Multi-scale failure mechanism is studied for GNS 316L under strain fatigue at 650 ℃. Gradient nanostructured materials have excellent fatigue resistance. At present, there are few research on the fatigue properties of gradient nanostructured (GNS) materials at high temperature. Herein, the multi-scale failure mechanism of GNS 316L steel at 650 °C is studied, and the high temperature fatigue tests under different strain amplitudes are conducted. Then, post-test microstructure observations were carried out to reveal the damage mechanisms, and the fatigue behavior was numerically simulated by crystal plasticity model. The experimental results show that the strength of the GNS 316L steel is still higher than that of the coarse-grained (CG) 316L steel at 650 °C, and the fatigue life of the GNS 316L steel is also higher than that of the CG one under strain fatigue loadings. The fatigue fracture results show that the fatigue crack presents a mixed propagation mode, and the crack source of GNS 316L transfers from surface to subsurface under low strain amplitude. The numerical results directly reflect the influence of the GNS surface layer on the plastic slip behavior. The fatigue failure mechanism of GNS 316L steel under strain-controlled cyclic loading at 650 °C was explained from a multi-scale perspective. This study provides data and method support for the application of GNS 316L steel at high temperature. [ABSTRACT FROM AUTHOR]
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- 2023
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8. Failure analysis and structural fatigue resistance design of multistage centrifugal pump shaft.
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Hua, Mengda, Cao, Chi, Cai, Youquan, Ge, Jie, Zhong, Fengping, and Mao, Jianfeng
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FATIGUE limit , *CENTRIFUGAL pumps , *STRESS concentration , *FATIGUE life , *SERVICE life , *ANIMAL products - Abstract
• Fatigue failure mechanism was elucidated for multi-stage centrifugal pump shaft. • Specific technical measures to prevent pump shaft failure were proposed. • Fatigue resistance design is performed for pump shaft structure and coupling. • Feasibility of the new pump shaft system has been verified by experiment. In the operation of multistage centrifugal pump, the pump shaft of 304 stainless steel is subjected to a variety of alternating loads. It is one of the parts prone to failure. The fracture microscopic observation, chemical composition analysis and mechanical property measurement of the fractured pump shaft are carried out. Through the fracture analysis, it is found that the pump shaft failure is caused by fatigue mechanism with characteristic of multi-source crack initiation, and there are many cavities and inclusions at the fracture. From the numerical analysis, it is found that there is significant stress concentration at the fracture, which exceeds the fatigue limit of the material and eventually leads to the fatigue fracture. Besides, the appropriate fillet radius and elastic coupling are designed for the pump shaft, which can effectively reduce the stress concentration and improve the service life of the pump shaft. Finally, the fatigue life of the improved pump shaft was experimentally verified. [ABSTRACT FROM AUTHOR]
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- 2023
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9. Temporal and spatial patterns, efficiency losses and impact factors of energy mismatch in China under environmental constraints.
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Jiang, Tangyang, Cao, Chi, Lei, Leyuan, Hou, Jie, Yu, Yang, and Jahanger, Atif
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ENERGY consumption , *INDUSTRIAL productivity , *ENERGY shortages , *POWER resources , *ENVIRONMENTAL regulations , *SPATIOTEMPORAL processes , *PANEL analysis - Abstract
Given the evident spatial disparity in China's energy consumption and economic development, achieving Pareto optimization of regional energy allocation efficiency proves to be a formidable challenge. Based on this, this paper ingeniously proposed an extended "labor-capital-energy-environment" resource mismatch mode, using 2004–2018 provincial panel data to measure and analyze the spatiotemporal pattern of China's energy mismatch and efficiency loss, while further investigating influencing factor. The results show that: (1) Although the degree of resource misallocation has decreased, the reduction of the number of provinces with excessive energy allocation and the serious shortage of energy allocation are the only effects of the optimization of energy resource misallocation, which has not significantly improved the situation overall. (2) Energy resource misallocation has grown to be a significant factor in China's losses in green total factor productivity (GTFP) brought on by resource misallocation. In addition, the extent of energy mismatch's loss in GTFP demonstrates the spatial heterogeneity of the "eastern > central > northeast > west" region. (3) Environmental regulation can significantly reduce energy mismatch and it is more successful at addressing the issue of excess energy than inadequate energy allocation. Also, the "rebound effect" of technological progress is the main factor aggravating the shortage of energy allocation. • We innovatively proposed an expanded "labor-capital-energy-environment" HK model to construct a theoretical framework for the impact of factor price distortions on GTFP. • The optimization of energy resource misallocation is only reflected in the serious shortage of energy allocation and the reduction of the number of provinces with excessive energy allocation. • The degree of GTFP loss of energy mismatch shows the regional heterogeneity of "eastern > central > northeast > west" spatially. • Environmental regulation can significantly improve the problems of energy mismatch and surplus. [ABSTRACT FROM AUTHOR]
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- 2023
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10. Corrigendum to "Investigation of radiation induced static mode degradation in Yb-Ce co-doped pulsed fiber amplifiers" [Opt. Laser Technol. 154 (2022) 108345].
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Wang, Bo, Cao, Chi, Zhang, Zhilun, Liao, Shibiao, Zhang, Anjun, Zhang, Xu, Xing, Yingbin, Chen, Gui, Zhou, Jun, Dai, Nengli, Peng, Jinggang, Li, Haiqing, and Li, Jinyan
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RADIATION , *LASERS , *FIBERS , *FIBER lasers - Published
- 2022
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11. Investigation of radiation induced static mode degradation in Yb-Ce co-doped pulsed fiber amplifiers.
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Wang, Bo, Cao, Chi, Zhang, Zhilun, Liao, Shibiao, Zhang, Anjun, Zhang, Xu, Xing, Yingbin, Chen, Gui, Zhou, Jun, Dai, Nengli, Peng, Jinggang, Li, Haiqing, and Li, Jinyan
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YTTERBIUM , *ERBIUM , *GAMMA rays , *FIBERS , *RADIATION , *INVESTIGATION reports - Abstract
• The radiation induced static mode degradation (SMD) was discovered and studied. • The threshold of SMD could be related with the composition of active fiber and increases with the increase of Ce. • When the Ce concentration increased by 35.5%, SMD threshold rose by 16% at most. We report on an experimental investigation of radiation induced static mode degradation in Yb-Ce co-doped pulsed fiber amplifiers. For investigating the impact of irradiation on beam quality, radiation-darkened fibers were irradiated by gamma rays. The laser properties of three types of fibers were investigated. With the pump power increased, static mode degradation appeared: M2 factor raised significantly and the output beam profile transformed from LP 01 into LP 11 shape without high-frequency component. The threshold of static mode degradation decreased with irradiation dose, and related to Yb-Ce co-doped fiber compositions. The doping of Ce benefits to the improvement of the static mode degradation threshold: in the case of the Ce concentration increasing by 35.5%, SMD threshold rose by 16% at most. [ABSTRACT FROM AUTHOR]
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- 2022
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12. More effective organics removal by amorphous MnOx assisted by micro-current than peroxymonosulfate addition: Performance and mechanism.
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Shi, Xinxin, Cao, Chi, Guo, Pengfei, Wen, Gang, Lu, Zheng, Shi, Julian, Peng, Dangcong, and Huang, Tinglin
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PEROXYMONOSULFATE ,METHYLENE blue ,DENSITY functional theory ,CARBON paper - Abstract
Peroxymonosulfate (PMS) addition into a MnO x system is generally believed to be an effective way for expediting organics removal. Whereas in this work, we found single MnO x with a micro-current got an even better oxidation performance comparing that with PMS addition. The carbon paper electrodeposited by amorphous MnO x (AMO) was used as cathode, and the micro-current (55 µA/cm
2 ) increased the methylene blue (MB) degradation rate by 6.1 times through enhancing the AMO oxidative ability in acidic media. At the same pH, the MB degradation rate in AMO (AMO-MC) system was close to that in AMO system with PMS addition (AMO-MC-PMS). More importantly, the MB mineralization in AMO-MC was about 1.6 times higher than that in AMO-MC-PMS. Similar phenomena were also investigated when using tetracycline (TC) as organic pollutant. The mechanisms of AMO-MC and AMO-MC-PMS for MB removal were comprehensively studied and compared. It was found that the micro-current prompted the Mn valence converting from high to low. Conversely, the PMS addition hindered this converting and impeded the direct oxidation of AMO. The GC-MS analysis indicated that the presence of PMS induced the formation of sulfoxide-containing intermediates (SCIs) which were difficult to be further degraded and resulted in the suppression of MB mineralization. Density functional theory (DFT) calculation indicated that the intermediates from AMO-MC were more facile to be attacked in an electrophilic way and adsorbed on the cathode than the SCIs. It proposed that the AMO with micro-current had the potential to remove organics efficiently, and blind PMS addition should be avoided. [Display omitted] • Amorphous MnO x (AMO) system can remove MB efficiently with the aid of a cathodic micro-current. • The micro-current can improve the activity of AMO system better than peroxymonosulfate (PMS). • Single AMO system got mineralization of 30% higher than the AMO-MC-PMS system. • Refractory intermediates were generated in the AMO-MC-PMS system. • PMS may not always play a positive role and blind addition should be avoided. [ABSTRACT FROM AUTHOR]- Published
- 2022
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13. Experimental investigation on creep behaviors and life prediction across phase-transformation of thermal aged 16MND5 steel.
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Mao, Jianfeng, Cai, Youquan, Cao, Chi, Hua, Mengda, Xie, Limin, Chen, Mingya, and Wang, Dasheng
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CREEP (Materials) , *SCANNING transmission electron microscopy , *TENSILE strength , *STEEL , *NUCLEAR power plants , *YIELD stress - Abstract
Reactor pressure vessel (RPV) is one of the key equipment for nuclear power plant, and long-term exposure to high temperature is an important factor causing its performance deterioration. Under core meltdown conditions, RPV steel experiences high temperature creep due to the In-Vessel Retention (IVR) mitigation measures. This paper aims to investigate high-temperature mechanical properties, especially for the creep behaviors of 16MND5 steel after thermal aging at 650 °C for 2000 h. The results showed that the yield stress and ultimate tensile strength of the 16MND5 steel are decreased, and the creep rupture time is rapidly shortened after thermal aging. The microstructure was analyzed by scanning and transmission electron microscopy (SEM, TEM). 16MND5 steel showed a typical bainitic phase before thermal aging. After 2000 h of thermal aging, the micro-grains were coarsened, and finally changed into a ferritic microstructure. Based on Larson-Miller (LM), Orr-Sherby-Dorn (OSD) parameters methods and Kachanov-Rabotnov (K–R) model to predict uniaxial creep life after thermal aging, the prediction results are satisfactory, and all within the double tolerance band. This work reveals the creep damage mechanism of 16MND5 steel after thermal aging, and provides basic data for the implementation of IVR strategy in nuclear power plants after long-term service. • Characterization of creep behaviors are achieved for 16MND5 steel before and after thermal aging. • Creep failure mechanism of thermal aged 16MND5 steel is explained by microscopic observation. • Influence of thermal aging on macro- and micro-creep failure of 16MND5 steel is understood in depth. • Creep life is well predicted by Larson-Miller and Orr-Sherby-Dorn parameters methods, and validated by experiment. • The K–R model accurately characterizes the three creep stages of thermal aged 16MND5 steel. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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14. Activation of α7nAChR by PNU282987 improves cognitive impairment through inhibiting oxidative stress and neuroinflammation in D-galactose induced aging via regulating α7nAChR/Nrf2/HO-1 signaling pathway.
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Zhang, Yawen, Ma, Rui, Wang, Wencheng, Deng, Qian, Cao, Chi, Yu, Chunyang, Li, Shulin, Shi, Lei, and Tian, Jianying
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COGNITION disorders , *OXIDATIVE stress , *NEUROINFLAMMATION , *GALACTOSE , *COGNITION - Abstract
Aging is an important risk factor for neurodegenerative diseases. The activation of α7 nicotinic acetylcholine receptor (α7nAChR) is involved in inflammation and cognition, but the specific role it plays in aging remains unknown. This study aimed to investigate the anti-aging effect of the activation of α7nAChR on aging rats and BV2 cells induced by D-galactose, as well as its potential mechanism. D-galactose induced an increase in the SA-β-Gal positive cells, expression of p16 and p21 in vivo and in vitro. α7nAChR selective agonist PNU282987 decreased levels of pro-inflammatory factors, MDA, and Aβ, enhanced SOD activity and levels of anti-inflammatory factor (IL10) in vivo. PNU282987 enhanced the expression of Arg1, decreased the expression of iNOS, IL1β and TNFα in vitro. PNU282987 upregulated the levels of α7nAChR, Nrf2 and HO-1 in vivo and in vitro. The results of Morris water maze and novel object recognition tests showed that PNU282987 improved cognitive impairment in aging rats. Furthermore, α7nAChR selective inhibitor methyllycaconitine (MLA) results were opposite with PNU282987. PNU282987 improves cognitive impairment through inhibiting oxidative stress and neuroinflammation in D-galactose induced aging via regulating the α7nAChR/Nrf2/HO-1 signaling pathway. Therefore, targeting the α7nAChR may be a viable therapeutic approach for anti-inflammaging and neurodegenerative diseases. • D-galactose induces microglial senescence and brain aging. • α7nAChR is downregulated in brain aging and senescent BV2 cells. • The activation of α7nAChR by PNU282987 inhibits oxidative stress and neuroinflammation in vivo and in vitro. • PNU282987 inhibits oxidative stress and neuroinflammation by upregulating the α7nAChR /Nrf2/HO-1 signaling pathway, thereby alleviating cognitive impairment caused by aging. [ABSTRACT FROM AUTHOR]
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- 2023
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15. S-adenosylmethionine improves cognitive impairment in D-galactose-induced brain aging by inhibiting oxidative stress and neuroinflammation.
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Zhang, Yawen, Ma, Rui, Deng, Qian, Wang, Wencheng, Cao, Chi, Yu, Chunyang, Li, Shulin, Shi, Lei, and Tian, Jianying
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OXIDATIVE stress , *NICOTINIC receptors , *BRAIN-derived neurotrophic factor , *COGNITION disorders , *NICOTINIC acetylcholine receptors , *ADENOSYLMETHIONINE , *MICROGLIA - Abstract
Oxidative stress and neuroinflammation play crucial roles in aging. S-adenosylmethionine (SAM), a popular supplement, is a potential antioxidant and candidate therapy for depression. This study aimed to evaluate the neuroprotective effects of SAM on D -galactose-induced brain aging and explore its underlying mechanisms. Brain aging model was established with D -galactose (180 mg/kg/day) for 8 weeks. During the last 4 weeks, SAM (16 mg/kg) was co-administrated with D -galactose. Behavior tests were used to assess cognitive function and depression-like behaviors of rats. Results showed that cognitive impairment and depression-like behaviors were reversed by SAM. SAM reduced neuronal cell loss, increased brain-derived neurotrophic factor level in the hippocampus, inhibited amyloid-β level and microglia activation, as well as pro-inflammatory factors levels in the hippocampus and serum. Further, SAM enhanced antioxidant capacity and attenuated cholinergic damage by reducing malondialdehyde levels, increasing acetylcholine levels, expression levels of α7 nicotinic acetylcholine receptor (α7nAChR), nuclear factor erythrocyte 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) in the hippocampus. Above all, SAM has a potential neuroprotective effect on ameliorating cognitive impairment in brain aging, which is related to inhibition of oxidative stress and neuroinflammation, as well as α7nAChR signals. Data will be made available on request. • Chronic D -galactose exposure leads to cognitive decline and depression-like behavior. • SAM has a neuroprotective effect by inhibiting oxidative stress and neuroinflammation. • SAM improves cognitive impairment by upregulating α7nAChR, Nrf2 and HO-1 protein levels. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
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