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The process and driving forces of rural hollowing in China under rapid urbanization 被引量:103
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作者 LIU Yansui LIU Yu +1 位作者 CHEN Yangfen LONG Hualou 《Journal of Geographical Sciences》 SCIE CSCD 2010年第6期876-888,共13页
Rural hollowing is a recent geographic phenomenon that has received significant attention in China, which is experiencing rapid urbanization. It has led to the wasteful use of rural land resources, and imposed obstacl... Rural hollowing is a recent geographic phenomenon that has received significant attention in China, which is experiencing rapid urbanization. It has led to the wasteful use of rural land resources, and imposed obstacles on the optimization of land use and coordinated urban-rural development. Rural hollowing has various forms of manifestation, which refers to the neglect and vacancy of rural dwellings, both of which can lead to damage and ultimate abandonment of rural dwellings. Damaged dwellings have different degrees of destruction, ranging from slight, moderate to severe. The evolutive process of rural hollowing in general has five stages, i.e., emergence, growth, flourishing, stability, and decline. Based on the combination of both regional economic development level and its physiographic features, the types of rural hollowing can be categorised as urban fringe, plain agricultural region, hilly agricultural region, and agro-pastoral region. Especially, the plain agricultural region is the most typical one in rural hollowing, which shows the spatial evolution of rural hollowing as a "poached egg" pattern with a layered hollow core and solid shape. Furthermore, the driving forces behind rural hollowing are identified as the pull of cities and push of rural areas. In particular, this paper identifies contributors to rural hollowing that include rural depopulation in relation to rapid urbanisation and economic change, land ownership and land use policy, and institutional barriers. 展开更多
关键词 rural hollowing hollowing villages settlement evolution rural depopulation rural residential land use China
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N-doped graphene quantum dot-decorated N-TiO2/P-doped porous hollow g-C_(3)N_(4) nanotube composite photocatalysts for antibiotic photodegradation and H2 production 被引量:2
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作者 Jingshu Yuan Yao Zhang +2 位作者 Xiaoyan Zhang Junjie Zhang Shen’gen Zhang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CSCD 2024年第1期165-178,共14页
Exclusive responsiveness to ultraviolet light (~3.2 eV) and high photogenerated charge recombination rate are the two primary drawbacks of pure TiO_(2). We combined N-doped graphene quantum dots (N-GQDs), morphology r... Exclusive responsiveness to ultraviolet light (~3.2 eV) and high photogenerated charge recombination rate are the two primary drawbacks of pure TiO_(2). We combined N-doped graphene quantum dots (N-GQDs), morphology regulation, and heterojunction construction strategies to synthesize N-GQD/N-doped TiO_(2)/P-doped porous hollow g-C_(3)N_(4) nanotube (PCN) composite photocatalysts (denoted as G-TPCN). The optimal sample (G-TPCN doped with 0.1wt% N-GQD, denoted as 0.1% G-TPCN) exhibits significantly enhanced photoabsorption, which is attributed to the change in bandgap caused by elemental doping (P and N), the improved light-harvesting resulting from the tube structure, and the upconversion effect of N-GQDs. In addition, the internal charge separation and transfer capability of0.1% G-TPCN are dramatically boosted, and its carrier concentration is 3.7, 2.3, and 1.9 times that of N-TiO_(2), PCN, and N-TiO_(2)/PCN(TPCN-1), respectively. This phenomenon is attributed to the formation of Z-scheme heterojunction between N-TiO_(2) and PCNs, the excellent electron conduction ability of N-GQDs, and the short transfer distance caused by the porous nanotube structure. Compared with those of N-TiO_(2), PCNs, and TPCN-1, the H2 production activity of 0.1%G-TPCN under visible light is enhanced by 12.4, 2.3, and 1.4times, respectively, and its ciprofloxacin (CIP) degradation rate is increased by 7.9, 5.7, and 2.9 times, respectively. The optimized performance benefits from excellent photoresponsiveness and improved carrier separation and migration efficiencies. Finally, the photocatalytic mechanism of 0.1% G-TPCN and five possible degradation pathways of CIP are proposed. This study clarifies the mechanism of multiple modification strategies to synergistically improve the photocatalytic performance of 0.1% G-TPCN and provides a potential strategy for rationally designing novel photocatalysts for environmental remediation and solar energy conversion. 展开更多
关键词 N-doped TiO_(2) N-doped graphene quantum dots P-doped g-C_(3)N_(4) porous hollow nanotube heterojunction photocatalysis
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Compositional and Hollow Engineering of Silicon Carbide/Carbon Microspheres as High-Performance Microwave Absorbing Materials with Good Environmental Tolerance 被引量:1
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作者 Lixue Gai Yahui Wang +5 位作者 Pan Wan Shuping Yu Yongzheng Chen Xijiang Han Ping Xu Yunchen Du 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第9期128-146,共19页
Microwave absorbing materials(MAMs)characterized by high absorption efficiency and good environmental tolerance are highly desirable in practical applications.Both silicon carbide and carbon are considered as stable M... Microwave absorbing materials(MAMs)characterized by high absorption efficiency and good environmental tolerance are highly desirable in practical applications.Both silicon carbide and carbon are considered as stable MAMs under some rigorous conditions,while their composites still fail to produce satisfactory microwave absorption performance regardless of the improvements as compared with the individuals.Herein,we have successfully implemented compositional and structural engineering to fabricate hollow Si C/C microspheres with controllable composition.The simultaneous modulation on dielectric properties and impedance matching can be easily achieved as the change in the composition of these composites.The formation of hollow structure not only favors lightweight feature,but also generates considerable contribution to microwave attenuation capacity.With the synergistic effect of composition and structure,the optimized SiC/C composite exhibits excellent performance,whose the strongest reflection loss intensity and broadest effective absorption reach-60.8 dB and 5.1 GHz,respectively,and its microwave absorption properties are actually superior to those of most SiC/C composites in previous studies.In addition,the stability tests of microwave absorption capacity after exposure to harsh conditions and Radar Cross Section simulation data demonstrate that hollow SiC/C microspheres from compositional and structural optimization have a bright prospect in practical applications. 展开更多
关键词 SiC/C composites Compositional engineering Hollow engineering Microwave absorption Environmental tolerance
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Hollow Ni Mo-based nitride heterojunction with super-hydrophilic/aerophobic surface for efficient urea-assisted hydrogen production 被引量:1
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作者 Yuying Fan Ying Gu +3 位作者 Dongxu Wang Yanqing Jiao Aiping Wu Chungui Tian 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第8期428-439,I0009,共13页
Hydrogen evolution reaction(HER)and urea oxidation reaction(UOR)are key reactions of the watercycling associated catalytic process/device.The design of catalysts with a super-hydrophilic/aerophobic structure and optim... Hydrogen evolution reaction(HER)and urea oxidation reaction(UOR)are key reactions of the watercycling associated catalytic process/device.The design of catalysts with a super-hydrophilic/aerophobic structure and optimized electron distribution holds great promise.Here,we have designed a threedimensional(3D)hollow Ni/NiMoN hierarchical structure with arrayed-sheet surface based on a onepot hydrothermal route for efficient urea-assisted HER based on a simple hydrothermal process.The Ni/NiMoN catalyst exhibits super-hydrophilic/aerophobic properties with a small droplet contact angle of 6.07°and an underwater bubble contact angle of 155.7°,thus facilitating an escape of bubbles from the electrodes.Density functional theory calculations and X-ray photoelectron spectroscopy results indicate the optimized electronic structure at the interface of Ni and NiMoN,which can promote the adsorption/desorption of reactants and intermediates.The virtues combining with a large specific surface area endow Ni/NiMoN with efficient catalytic activity of low potentials of 25 mV for HER and 1.33 V for UOR at10 mA cm^(-2).The coupled HER and UOR system demonstrates a low cell voltage of 1.42 V at 10 mA cm^(-2),which is approximately 209 mV lower than water electrolysis. 展开更多
关键词 Hydrogen evolution Transition metal nitrides Hollow heterojunctions Urea electrooxidation Super hydrophilic/aerophobic
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Co/CoO heterojunction rich in oxygen vacancies introduced by O_(2) plasma embedded in mesoporous walls of carbon nanoboxes covered with carbon nanotubes for rechargeable zinc-air battery 被引量:1
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作者 Leijun Ye Weiheng Chen +1 位作者 Zhong-Jie Jiang Zhongqing Jiang 《Carbon Energy》 SCIE EI CAS CSCD 2024年第7期14-25,共12页
Herein,Co/CoO heterojunction nanoparticles(NPs)rich in oxygen vacancies embedded in mesoporous walls of nitrogen-doped hollow carbon nanoboxes coupled with nitrogen-doped carbon nanotubes(P-Co/CoOV@NHCNB@NCNT)are well... Herein,Co/CoO heterojunction nanoparticles(NPs)rich in oxygen vacancies embedded in mesoporous walls of nitrogen-doped hollow carbon nanoboxes coupled with nitrogen-doped carbon nanotubes(P-Co/CoOV@NHCNB@NCNT)are well designed through zeolite-imidazole framework(ZIF-67)carbonization,chemical vapor deposition,and O_(2) plasma treatment.As a result,the threedimensional NHCNBs coupled with NCNTs and unique heterojunction with rich oxygen vacancies reduce the charge transport resistance and accelerate the catalytic reaction rate of the P-Co/CoOV@NHCNB@NCNT,and they display exceedingly good electrocatalytic performance for oxygen reduction reaction(ORR,halfwave potential[EORR,1/2=0.855 V vs.reversible hydrogen electrode])and oxygen evolution reaction(OER,overpotential(η_(OER,10)=377mV@10mA cm^(−2)),which exceeds that of the commercial Pt/C+RuO_(2) and most of the formerly reported electrocatalysts.Impressively,both the aqueous and flexible foldable all-solid-state rechargeable zinc-air batteries(ZABs)assembled with the P-Co/CoOV@NHCNB@NCNT catalyst reveal a large maximum power density and outstanding long-term cycling stability.First-principles density functional theory calculations show that the formation of heterojunctions and oxygen vacancies enhances conductivity,reduces reaction energy barriers,and accelerates reaction kinetics rates.This work opens up a new avenue for the facile construction of highly active,structurally stable,and cost-effective bifunctional catalysts for ZABs. 展开更多
关键词 HETEROJUNCTION oxygen evolution/reduction reaction oxygen vacancies rechargeable zinc–air battery three‐dimensional nitrogen‐doped hollow carbon nanoboxes
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Research on thermal insulation materials properties under HTHP conditions for deep oil and gas reservoir rock ITP-Coring 被引量:1
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作者 Zhi-Qiang He He-Ping Xie +4 位作者 Ling Chen Jian-Ping Yang Bo Yu Zi-Jie Wei Ming-Zhong Gao 《Petroleum Science》 SCIE EI CAS CSCD 2024年第4期2625-2637,共13页
Deep oil and gas reservoirs are under high-temperature conditions,but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability... Deep oil and gas reservoirs are under high-temperature conditions,but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability,resulting in distorted resource assessments.The development of in situ temperaturepreserved coring(ITP-Coring)technology for deep reservoir rock is urgent,and thermal insulation materials are key.Therefore,hollow glass microsphere/epoxy resin thermal insulation materials(HGM/EP materials)were proposed as thermal insulation materials.The materials properties under coupled hightemperature and high-pressure(HTHP)conditions were tested.The results indicated that high pressures led to HGM destruction and that the materials water absorption significantly increased;additionally,increasing temperature accelerated the process.High temperatures directly caused the thermal conductivity of the materials to increase;additionally,the thermal conduction and convection of water caused by high pressures led to an exponential increase in the thermal conductivity.High temperatures weakened the matrix,and high pressures destroyed the HGM,which resulted in a decrease in the tensile mechanical properties of the materials.The materials entered the high elastic state at 150℃,and the mechanical properties were weakened more obviously,while the pressure led to a significant effect when the water absorption was above 10%.Meanwhile,the tensile strength/strain were 13.62 MPa/1.3%and 6.09 MPa/0.86%at 100℃ and 100 MPa,respectively,which meet the application requirements of the self-designed coring device.Finally,K46-f40 and K46-f50 HGM/EP materials were proven to be suitable for ITP-Coring under coupled conditions below 100℃ and 100 MPa.To further improve the materials properties,the interface layer and EP matrix should be optimized.The results can provide references for the optimization and engineering application of materials and thus technical support for deep oil and gas resource development. 展开更多
关键词 Deep oil and gas reservoir rock In situ temperature-preserved coring(ITPCoring) Hollow glass microsphere/epoxy resin thermal insulation materials(HGM/EP materials) High-temperature and high-pressure(HTHP) Physical and mechanical properties
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Hollowing out of the Real Economy: Evidence from China's Listed FirmsI 被引量:2
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作者 Xu Li Xiang Shao Zhigang Tao 《Frontiers of Economics in China-Selected Publications from Chinese Universities》 2016年第3期390-409,共20页
The paper studies an often-observed phenomenon of diversification of manufacturing firms into real estate development in East Asian economies. Utilizing a sudden change in China's accounting standards that requires f... The paper studies an often-observed phenomenon of diversification of manufacturing firms into real estate development in East Asian economies. Utilizing a sudden change in China's accounting standards that requires firms to disclose information about their real estate holdings for investment purpose (or investment property), we examine both the impact of such diversification on firms' investment in their original business and the stock market response to such diversification. Our results confirm there exists underinvestment in original business (or hollowing out of the real economy) for firms diversifying into real estate, and that there is a lack of investor response to such diversification, in both short-rim and long-run. Our study calls for further research on the role of real estate development in the long-run competitiveness of developing economies. 展开更多
关键词 China investment property hollowing out of real economy stockmarket returns
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Plasma density enhancement in radio-frequency hollow electrode discharge
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作者 贺柳良 何锋 欧阳吉庭 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第4期44-51,共8页
The plasma density enhancement outside hollow electrodes in capacitively coupled radio-frequency(RF) discharges is investigated by a two-dimensional(2D) particle-in-cell/Monte-Carlo collision(PIC/MCC) model. Results s... The plasma density enhancement outside hollow electrodes in capacitively coupled radio-frequency(RF) discharges is investigated by a two-dimensional(2D) particle-in-cell/Monte-Carlo collision(PIC/MCC) model. Results show that plasma exists inside the cavity when the sheath inside the hollow electrode hole is fully collapsed, which is an essential condition for the plasma density enhancement outside hollow electrodes. In addition, the existence of the electron density peak at the orifice is generated via the hollow cathode effect(HCE), which plays an important role in the density enhancement. It is also found that the radial width of bulk plasma at the orifice affects the magnitude of the density enhancement, and narrow radial plasma bulk width at the orifice is not beneficial to obtain high-density plasma outside hollow electrodes.Higher electron density at the orifice, combined with larger radial plasma bulk width at the orifice,causes higher electron density outside hollow electrodes. The results also imply that the HCE strength inside the cavity cannot be determined by the magnitude of the electron density outside hollow electrodes. 展开更多
关键词 RF capacitively coupled plasma sources plasma density enhancement hollow cathodeeffect hollow electrode
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Hollow cathode effect in radio frequency hollow electrode discharge in argon
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作者 贺柳良 何锋 欧阳吉庭 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第3期496-502,共7页
Radio frequency capacitively coupled plasma source(RF-CCP)with a hollow electrode can increase the electron density through the hollow cathode effect(HCE),which offers a method to modify the spatial profiles of the pl... Radio frequency capacitively coupled plasma source(RF-CCP)with a hollow electrode can increase the electron density through the hollow cathode effect(HCE),which offers a method to modify the spatial profiles of the plasma density.In this work,the variations of the HCE in one RF period are investigated by using a two-dimensional particle-in-cell/Monte-Carlo collision(PIC/MCC)model.The results show that the sheath electric field,the sheath potential drop,the sheath thickness,the radial plasma bulk width,the electron energy distribution function(EEDF),and the average electron energy in the cavity vary in one RF period.During the hollow electrode sheath's expansion phase,the secondary electron heating and sheath oscillation heating in the cavity are gradually enhanced,and the frequency of the electron pendular motion in the cavity gradually increases,hence the HCE is gradually enhanced.However,during the hollow electrode sheath's collapse phase,the secondary electron heating is gradually attenuated.In addition,when interacting with the gradually collapsed hollow electrode sheaths,high-energy plasma bulk electrons in the cavity will lose some energy.Furthermore,the frequency of the electron pendular motion in the cavity gradually decreases.Therefore,during the hollow electrode sheath's collapse phase,the HCE is gradually attenuated. 展开更多
关键词 hollow cathode effect radio frequency hollow electrode particle-in-cell/Monte-Carlo collision(PIC/MCC)model
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Research on casing deformation prevention technology based on cementing slurry system optimization
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作者 Yan Yan Meng Cai +3 位作者 Wen-Hai Ma Xiao-Chuan Zhang Li-Hong Han Yong-Hong Liu 《Petroleum Science》 SCIE EI CAS CSCD 2024年第2期1231-1240,共10页
The casing deformation prevention technology based on the optimization of cement slurry is proposed to reduce the casing deformation of shale oil and gas wells during hydraulic fracturing. In this paper, the fracture ... The casing deformation prevention technology based on the optimization of cement slurry is proposed to reduce the casing deformation of shale oil and gas wells during hydraulic fracturing. In this paper, the fracture mechanism of hollow particles in cement sheath was firstly analyzed by discrete element method, and the effect of hollow particles in cement on casing deformation was investigated by laboratory experiment method. Finally, field test was carried out to verify the improvement effect of the casing deformation based on cement slurry modification. The results show that the formation displacement can be absorbed effectively by hollow particles inside the cement transferring the excessive deformation away from casing. The particles in the uncemented state provide deformation space during formation slipping. The casing with diameter of 139.7 mm could be passed through by bridge plug with the diameter of 99 mm when the mass ratio of particle/cement reaches 1:4. According to the field test feedback, the method based on optimization of cement slurry can effectively reduce the risk of casing deformation, and the recommended range of hollow microbeads content in the cement slurry is between 15% and 25%. 展开更多
关键词 Cement slurry Hollow ceramsite Casing deformation Formation slip Field test
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Atomically Dispersed Ruthenium Catalysts with Open Hollow Structure for Lithium-Oxygen Batteries
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作者 Xin Chen Yu Zhang +5 位作者 Chang Chen Huinan Li Yuran Lin Ke Yu Caiyun Nan Chen Chen 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第2期154-164,共11页
Lithium–oxygen battery with ultrahigh theoretical energy density is considered a highly competitive next-generation energy storage device,but its practical application is severely hindered by issues such as difficult... Lithium–oxygen battery with ultrahigh theoretical energy density is considered a highly competitive next-generation energy storage device,but its practical application is severely hindered by issues such as difficult decomposition of discharge products at present.Here,we have developed N-doped carbon anchored atomically dispersed Ru sites cathode catalyst with open hollow structure(h-RuNC)for Lithium–oxygen battery.On one hand,the abundance of atomically dispersed Ru sites can effectively catalyze the formation and decomposition of discharge products,thereby greatly enhancing the redox kinetics.On the other hand,the open hollow structure not only enhances the mass activity of atomically dispersed Ru sites but also improves the diffusion efficiency of catalytic molecules.Therefore,the excellent activity from atomically dispersed Ru sites and the enhanced diffusion from open hollow structure respectively improve the redox kinetics and cycling stability,ultimately achieving a high-performance lithium–oxygen battery. 展开更多
关键词 Atomically dispersed Open hollow structure Discharge product LITHIUM Oxygen battery
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Hollow ZIF-67-derived Co@N-doped carbon nanotubes boosting the hydrogenation of phenolic compounds to alcohols
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作者 Zhihao Guo Jiuxuan Zhang +3 位作者 Lanlan Chen Chaoqun Fan Hong Jiang Rizhi Chen 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第2期157-166,共10页
The selective hydrogenation of highly toxic phenolic compounds to generate alcohols with thermal stability,environmental friendliness,and non-toxicity is of great importance.Herein,a series of Co-based catalysts,named... The selective hydrogenation of highly toxic phenolic compounds to generate alcohols with thermal stability,environmental friendliness,and non-toxicity is of great importance.Herein,a series of Co-based catalysts,named Co@NCNTs,were designed and constructed by direct pyrolysis of hollow ZIF-67(HZIF-67)under H_(2)/Ar atmosphere.The evolution of the catalyst surface from the shell layer assembled by ZIF-67-derived particles to the in situ-grown hollow nitrogen-doped carbon nanotubes(NCNTs)with certain length and density is achieved by adjusting the pyrolysis atmosphere and temperature.Due to the synergistic effects of in situ-formed hollow NCNTs,well-dispersed Co nanoparticles,and intact carbon matrix,the as-prepared Co@NCNTs-0.10-450 catalyst exhibits superior catalytic performance in the hydrogenation of phenolic compounds to alcohols.The turnover frequency value of Co@NCNTs-0.10-450is 3.52 h^(-1),5.9 times higher than that of Co@NCNTs-0.40-450 and 4.5 times higher than that of Co@NCNTs-0.10-550,exceeding most previously reported non-noble metal catalysts.Our findings provide new insights into the development of non-precious metal,efficient,and cost-effective metal-organic framework-derived catalysts for the hydrogenation of phenolic compounds to alcohols. 展开更多
关键词 Phenolic compounds Hollow ZIF-67 pyrolysis Nitrogen-doped carbon nanotubes Reduction Multiphase reaction Catalysis
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Gradient‑Layered MXene/Hollow Lignin Nanospheres Architecture Design for Flexible and Stretchable Supercapacitors
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作者 Haonan Zhang Cheng Hao +6 位作者 Tongtong Fu Dian Yu Jane Howe Kaiwen Chen Ning Yan Hao Ren Huamin Zhai 《Nano-Micro Letters》 SCIE EI CAS 2025年第2期447-462,共16页
With the rapid development of flexible wearable electronics,the demand for stretchable energy storage devices has surged.In this work,a novel gradient-layered architecture was design based on single-pore hollow lignin... With the rapid development of flexible wearable electronics,the demand for stretchable energy storage devices has surged.In this work,a novel gradient-layered architecture was design based on single-pore hollow lignin nanospheres(HLNPs)-intercalated two-dimensional transition metal carbide(Ti_(3)C_(2)T_(x) MXene)for fabricating highly stretchable and durable supercapacitors.By depositing and inserting HLNPs in the MXene layers with a bottom-up decreasing gradient,a multilayered porous MXene structure with smooth ion channels was constructed by reducing the overstacking of MXene lamella.Moreover,the micro-chamber architecture of thin-walled lignin nanospheres effectively extended the contact area between lignin and MXene to improve ion and electron accessibility,thus better utilizing the pseudocapacitive property of lignin.All these strategies effectively enhanced the capacitive performance of the electrodes.In addition,HLNPs,which acted as a protective phase for MXene layer,enhanced mechanical properties of the wrinkled stretchable electrodes by releasing stress through slip and deformation during the stretch-release cycling and greatly improved the structural integrity and capacitive stability of the electrodes.Flexible electrodes and symmetric flexible all-solid-state supercapacitors capable of enduring 600%uniaxial tensile strain were developed with high specific capacitances of 1273 mF cm^(−2)(241 F g^(−1))and 514 mF cm^(−2)(95 F g^(−1)),respectively.Moreover,their capacitances were well preserved after 1000 times of 600%stretch-release cycling.This study showcased new possibilities of incorporating biobased lignin nanospheres in energy storage devices to fabricate stretchable devices leveraging synergies among various two-dimensional nanomaterials. 展开更多
关键词 Hollow lignin nanospheres MXene Gradient-layered architecture Wrinkled electrodes Stretchable supercapacitors
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Influence of cyclic ignition and steady-state operation on a 1–2 A barium tungsten hollow cathode
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作者 Fufeng WANG Tianhang MENG +1 位作者 Zhongxi NING Ximing ZHU 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第12期121-131,共11页
Booming low-power electric propulsion systems require 1–2 A hollow cathodes.Such cathodes are expected to go through more frequent ignitions in the low orbit,but the impact of cyclic ignitions on such 1–2 A barium t... Booming low-power electric propulsion systems require 1–2 A hollow cathodes.Such cathodes are expected to go through more frequent ignitions in the low orbit,but the impact of cyclic ignitions on such 1–2 A barium tungsten hollow cathodes with a heater was not clear.In this study,a 12,638-cyclic ignition test and a 6,000-hour-long life test on two identical cathodes were carried out.The discharge voltage of the cathode and the erosion of the orifice after cyclic ignition were all larger than that of the cathode after stable operation.This indicated that the impact of cycle ignition on the discharge performance of a low current BaO-W cathode with a heater was higher than that of stable operation.The results of the ion energy distribution function measured during the ignition period indicated that the main reason for the orifice expansion was ion bombardment.Therefore,it was necessary to pay attention to the number of ignitions for the lifetime of this kind of cathode. 展开更多
关键词 hollow cathode cyclic ignition stable operation ORIFICE ion bombardment
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Recent advances in producing hollow carbon spheres for use in sodium−sulfur and potassium−sulfur batteries
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作者 QI Zi-xin LUO Sai-nan +4 位作者 RUAN Jia-feng YUAN Tao PANG Yue-peng YANG Jun-he ZHENG Shi-you 《新型炭材料(中英文)》 SCIE EI CAS CSCD 北大核心 2024年第5期824-843,共20页
Sodium-sulfur(Na-S)and potassium-sulfur(K-S)batteries for use at room temperature have received widespread attention because of the abundance and low cost of their raw materials and their high energy density.However,t... Sodium-sulfur(Na-S)and potassium-sulfur(K-S)batteries for use at room temperature have received widespread attention because of the abundance and low cost of their raw materials and their high energy density.However,their development is restricted by the shuttling of polysulfides,large volume expansion and poor conductivity.To overcome these obstacles,an effective approach is to use carbon-based materials with abundant space for the sulfur that has sulfiphilic sites to immobilize it,and a high electrical conductivity.Hollow carbon spheres(HCSs)with a controllable structure and composition are promising for this purpose.We consider recent progress in optimizing the electrochemical performance of Na-/K-S batteries by using these materials.First,the advantages of HCSs,their synthesis methods,and strategies for preparing HCSs/sulfur composite materials are reviewed.Second,the use of HCSs in Na-/K-S batteries,along with mechanisms underlying the resulting performance improvement,are discussed.Finally,prospects for the further development of HCSs for metal−S batteries are presented. 展开更多
关键词 Hollow carbon sphere Sodium-sulfur batteries Shuttle effect Potassium-sulfur batteries Electrochemical performance
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Hyperbranched polymer hollow-fiber-composite membranes for pervaporation separation of aromatic/aliphatic hydrocarbon mixtures
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作者 Tong Liu Hao Sun +5 位作者 Xiangqiong Wang Jie Li Zhanquan Zhang Pei Wu Naixin Wang Quanfu An 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第5期13-22,共10页
The separation of aromatic/aliphatic hydrocarbon mixtures is crucial in the petrochemical industry.Pervaporation is regarded as a promising approach for the separation of aromatic compounds from alkanes. Developing me... The separation of aromatic/aliphatic hydrocarbon mixtures is crucial in the petrochemical industry.Pervaporation is regarded as a promising approach for the separation of aromatic compounds from alkanes. Developing membrane materials with efficient separation performance is still the main task since the membrane should provide chemical stability, high permeation flux, and selectivity. In this study, the hyperbranched polymer(HBP) was deposited on the outer surface of a polyvinylidene fluoride(PVDF)hollow-fiber ultrafiltration membrane by a facile dip-coating method. The dip-coating rate, HBP concentration, and thermal cross-linking temperature were regulated to optimize the membrane structure.The obtained HBP/PVDF hollow-fiber-composite membrane had a good separation performance for aromatic/aliphatic hydrocarbon mixtures. For the 50%/50%(mass) toluene/n-heptane mixture, the permeation flux of optimized composite membranes could reach 1766 g·m^(-2)·h^(-1), with a separation factor of 4.1 at 60℃. Therefore, the HBP/PVDF hollow-fiber-composite membrane has great application prospects in the pervaporation separation of aromatic/aliphatic hydrocarbon mixtures. 展开更多
关键词 Aromatic/aliphatic hydrocarbons Hyperbranched polymer PERVAPORATION Hollow fiber membrane DIP-COATING
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Controllable fabrication of FeCoS_(4) nanoparticles/S-doped bowl-shaped hollow carbon as efficient lithium storage anode
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作者 Ming Zhou Mengrong Wu +8 位作者 Haiwei Yu Xiangjun Zheng Kuan Shen Xingmei Guo Yuanjun Liu Fu Cao Hongxing Gu Qinghong Kong Junhao Zhang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第3期78-88,共11页
To address the low conductivity and easy agglomeration of transition metal sulfide nanoparticles,FeCoS_(4) nanoparticles embedded in S-doped hollow carbon(FeCoS_(4)@S-HC)composites were successfully fabricated through... To address the low conductivity and easy agglomeration of transition metal sulfide nanoparticles,FeCoS_(4) nanoparticles embedded in S-doped hollow carbon(FeCoS_(4)@S-HC)composites were successfully fabricated through a combination of hydrothermal processes and sulfidation treatment.The unique bowlshaped FeCoS_(4)/S-HC composites exhibit excellent structural stability with a high specific surface area of 303.7 m^(2)·g^(-1) and a pore volume of 0.93 cm^(3)·g^(-1).When applied as anode material for lithium-ion batteries,the FeCoS_(4)@S-HC anode exhibits efficient lithium storage with high reversible specific capacity(970.2 mA·h·g^(-1) at 100 mA·g^(-1))and enhanced cycling stability(574 mA·h·g^(-1) at 0.2 A·g^(-1) after 350 cycles,a capacity retention of 84%).The excellent lithium storage is attributed to the fact that the bimetallic FeCoS_(4) nanoparticles with abundant active sites can accelerate the electrochemical reaction kinetics,and the bowl-shaped S-HC structure can provide a stable mechanical structure to suppress volume expansion. 展开更多
关键词 Bimetallic sulfides Bowl-shaped hollow carbon S doping Buffering volume expand Lithium-ion batteries
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Driving inward growth of lithium metal in hollow microcapsule hosts by heteroatom‐controlled nucleation
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作者 Siwon Kim Hong Rim Shin +2 位作者 Ki Jae Kim Min‐Sik Park Jong‐Won Lee 《Carbon Energy》 SCIE EI CAS CSCD 2024年第8期262-272,共11页
The application of Li metal anodes in rechargeable batteries is impeded by safety issues arising from the severe volume changes and formation of dendritic Li deposits.Three‐dimensional hollow carbon is receiving incr... The application of Li metal anodes in rechargeable batteries is impeded by safety issues arising from the severe volume changes and formation of dendritic Li deposits.Three‐dimensional hollow carbon is receiving increasing attention as a host material capable of accommodating Li metal inside its cavity;however,uncontrollable and nonuniform deposition of Li remains a challenge.In this study,we synthesize metal–organic framework‐derived carbon microcapsules with heteroatom clusters(Zn and Ag)on the capsule walls and it is demonstrated that Ag‐assisted nucleation of Li metal alters the outward‐to‐inward growth in the microcapsule host.Zn‐incorporated microcapsules are prepared via chemical etching of zeolitic imidazole framework‐8 polyhedra and are subsequently decorated with Ag by a galvanic displacement reaction between Ag^(+) and metallic Zn.Galvanically introduced Ag significantly reduces the energy barrier and increases the reaction rate for Li nucleation in the microcapsule host upon Li plating.Through combined electrochemical,microstructural,and computational studies,we verify the beneficial role of Ag‐assisted Li nucleation in facilitating inward growth inside the cavity of the microcapsule host and,in turn,enhancing electrochemical performance.This study provides new insights into the design of reversible host materials for practical Li metal batteries. 展开更多
关键词 hollow carbon hosts lithium metal batteries lithium plating metal-organic frameworks NUCLEATION
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Revealing interfacial charge redistribution of homologous Ru-RuS_(2) heterostructure toward robust hydrogen oxidation reaction
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作者 Yi Liu Lianrui Cheng +5 位作者 Shuqing Zhou Yuting Yang Chenggong Niu Tayirjan Taylor Isimjan Bao Wang Xiulin Yang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第7期332-339,共8页
Precisely tailoring the surface electronic structures of electrocatalysts for optimal hydrogen binding energy and hydroxide binding energy is vital to improve the sluggish kinetics of hydrogen oxidation reac-tion(HOR)... Precisely tailoring the surface electronic structures of electrocatalysts for optimal hydrogen binding energy and hydroxide binding energy is vital to improve the sluggish kinetics of hydrogen oxidation reac-tion(HOR).Herein,we employ a partial desulfurization strategy to construct a homologous Ru-RuS_(2) heterostructure anchored on hollow mesoporous carbon nanospheres(Ru-RuS_(2)@C).The disparate work functions of the heterostructure contribute to the spontaneous formation of a unique built-in electric field,accelerating charge transfer and boosting conductivity of electrocatalyst.Consequently,Ru-RuS_(2)@C exhibits robust HOR electrocatalytic activity,achieving an exchange current density and mass activity as high as 3.56 mA cm^(-2) and 2.13 mAμg_(Ru)^(-1),respectively.exceeding those of state-of-the-art Pt/C and most contemporary Ru-based HOR electrocatalysts.Surprisingly,Ru-RuS_(2)@C can tolerate 1000 ppm of cO that lacks in Pt/C.Comprehensive analysis reveals that the directional electron transfer across Ru-RuS_(2) heterointerface induces local charge redistribution in interfacial region,which optimizes and balances the adsorption energies of H and OH species,as well as lowers the energy barrier for water formation,thereby promoting theHoR performance. 展开更多
关键词 HETEROSTRUCTURE Hollow spherical structure Hydrogen oxidation reaction Charge redistribution Density functional calculation
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A novel Ag/ZnO core-shell structure for efficient sterilization synergizing antibiotics and subsequently removing residuals
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作者 Wenmei Han Wenli Wang +4 位作者 Jie Fan Runping Jia Xuchun Yang Tong Wu Qingsheng Wu 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第2期366-377,共12页
The massive use of antibiotics has led to the aggravation of bacterial resistance and also brought environmental pollution problems.This poses a great threat to human health.If the dosage of antibiotics is reduced by ... The massive use of antibiotics has led to the aggravation of bacterial resistance and also brought environmental pollution problems.This poses a great threat to human health.If the dosage of antibiotics is reduced by increasing its bactericidal performance,the emergence of drug resistance is certainly delayed,so that there's not enough time for developing drug resistance during treatment.Therefore,we selected typical representative materials of metal Ag and semiconductor ZnO nano-bactericides to design and synthesize Ag/ZnO hollow core-shell structures(AZ for short).Antibiotics are grafted on the surface of AZ through rational modification to form a composite sterilization system.The research results show that the antibacterial efficiency of the composite system is significantly increased,from the sum(34.7%+22.8%-57.5%)of the antibacterial efficiency of AZ and gentamicin to 80.2%,net synergizes 22.7%,which fully reflects the effect of 1+1>2.Therefore,the dosage of antibiotics can be drastically reduced in this way,which makes both the possibility of bacterial resistance and medical expenses remarkably decrease.Subsequently,residual antibiotics can be degraded under simple illumination using AZ-self as a photocatalyst,which cuts off the path of environmental pollution.In short,such an innovative route has guiding significance for drug resistance. 展开更多
关键词 Ag/ZnO hollow Core-shell structures ANTIBIOTICS GENTAMYCIN Synergistic sterilization PHOTODEGRADATION
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