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A multistimuli-responsive fluorescent hydrogel based on a fluorescence response to macromolecular segmental motion

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Nano Research 2023年第10期16卷 12098-12105页

作者： Botian Li Bo Yan Jian Wang Yichi Zhang Ziyan Qiu Jundang Liang Qiong Zhou College of New Energy and Materials China University of PetroleumBeijing 102249China

Fluorescent hydrogels with fast and reversible responses have attracted extensive attention, and it remains a challenge to designmultistimuli-responsive fluorescent hydrogel through a facile and versatile method. Meanwhile, the segmental motion inhydrogels is of significance for the various functions of hydrogels such as chemical reactivity, self-healing, and mechanicalstrength, etc., however, it is difficult and complicated to in situ investigate the segmental motion under different conditions. In thiswork, a multistimuli-responsive fluorescent hydrogel was designed and fabricated by introducing a tetraphenylethylene (TPE)derivative as a nonaggregated crosslinker in the gel network. Since the intermolecular rotation of TPE at the crosslinking pointwas directly integrated with the dynamic conformational transition of the macromolecular network, the mobility of macromolecularsegments can be monitored by the fluorescence intensity of the hydrogel. The prepared hydrogel has promising fluorescenceresponses to temperature, pH, metal ions, and hydrogen bonding agents, and characterization of the fluorescence and the chainsegmental motion showed that the weaker the mobility of the network macromolecular chain is, the stronger the fluorescenceintensity is. Furthermore, due to the multistimuli-responsive fluorescence of the hydrogel, such fluorescent hydrogels can bedesigned as reversible patterning displays and biomimetic color/shape adjustable actuators, with various potential applications.

关键词： multistimuli response fluorescent hydrogel aggregation-induced emission(AIE) segment motion biomimetic actuator

High flashover strength and superhydrophobic coatings by constructing porous surface structure

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High Voltage 2023年第4期8卷 728-738页

作者： Mengtao Li Tingxin Chen Xiaobo Guo Lei Dong Jiming Chen Mingxiao Zhu College of New Energy China University of Petroleum(East China)QingdaoChina

Flashover is prone to occur in composite insulation structures such as vacuum-solid and gas-solid,which are universally employed in high-voltage power equipment.In this study,a high flashover strength and superhydrophobic coating were proposed by constructing porous surface morphology.Octadecyl trichlorosilane(OTS)particles were prepared by hydrolysis condensation reaction,and thereafter sprayed onto the substrate surface to form a porous and rough surface structure with hundreds of nanometres of dispersed pores and pits.The coating endowed epoxy resin with maximum 44%flashover voltage increase and the superhydrophobic surface with water contact angle of 158.4°.Since the pore size in OTS coating is close to electron mean free path in atmospheric condition,the collisional ionisation can be effectively hindered,which suppresses the micro-discharge around the triple junction and improves the flashover strength.The present approach provides a new insight for simultaneously improving flashover strength and superhydrophobic properties of dielectric insulation.

关键词： coating strength flash

N,S-codoped porous carbon nanosheets decorated with Fe_(3)C nanoparticles as high-performance anode materials for lithium ion hybrid supercapacitors

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Rare Metals 2022年第7期41卷 2517-2526页

作者： Lin Gao Lu-Lu Zhang Xue-Lin Yang college of Electrical Engineering&new energy Hubei Collaborative Innovation Center for Microgrid of New EnergyThree Gorges UniversityYichang 443002China

The practical applications of carbon anode for lithium-ion batteries(LIBs)are largely obstructed by their moderate rate capability and cyclic stability.Herein,we report a N,S-codoped porous carbon nanosheet(NSC)decorated with Fe_(3)C nanoparticles(Fe_(3)C/NSC)by a one-pot pyrolysis process.The high surface area and abundant defects of NSC can not only promote electrons and ions transfer,but also induce high pseudocapacitive contribution.More importantly,the synergistic catalysis effect of Fe-Nx and Fe_(3)C can catalyze the reversible conversion of some solid electrolyte interface(SEI)components to offer excess capacity during cycling.As expected,the Fe_(3)C-NSC anode delivers a discharge capacity of750 mAh·g^(-1)under a current density of 0.5 A·g^(-1)through 500 cycles and retains a dis-charge capacity of 366 mAh·g^(-1)at 4 A·g^(-1)after 1600 cycles,respectively.Most importantly,the lithium-ion capacitors based on Fe_(3)C/NSC anode demonstrate a high energy density of 249.5 Wh·kg^(-1)at 560 W·kg^(-1).

关键词： Fe_(3)C/NSC Lithium-ion batteries Pseudocapacitive behavior Lithium-ion capacitors

Enhancement of Natural Convection for Cooling Active Antenna Unit Device in 5G Base Station

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Journal of Thermal Science 2022年第5期31卷 1551-1564页

作者： ZHANG Dexin DING Bin ZHU Chuanyong GONG Liang College of New Energy China University of Petroleum(East China)Qingdao266580China

The Active Antenna Unit(AAU)on the outdoor tower is the key equipment to support the mobile communication of 5G.To suppress the overheating of AAU in summer,effective cooling measures are essential.In the present study,a numerical model of an AAU device with two chips in the outdoor environment was established to explore the surface temperature distribution under a coupling heat transfer process with natural convection and solar radiation was obtained.Moreover,the effects of the fin number,the fin height and the heat flux were discussed on the cooling performance.The results proved that the fins with a number of 12 presented the best cooling performance in this paper.By contrast,increasing the height of fins was still an effective way to improve the cooling performance of fins in outdoor conditions and to resist the thermal shock of chips.Besides,punching through holes on the fins,adding graphite heat spreader and reducing surface emissivity are effective ways to improve the cooling performance.After the optimizations,the maximum temperature decreased by 3.5℃in total.In other words,the contribution of these optimizations to the cooling performance was equivalent to an increase of fin height in 9 mm.

关键词： natural convection heat transfer enhancement structural optimization 5G base station

Analysis of the Heat Transfer Efficiency of an Automobile Engine under Different Grille Opening and Closing Conditions

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Fluid Dynamics & Materials Processing 2022年第2期18卷 345-354页

作者： Jian Song College of New Energy Vehicles Jingzhou Institute of TechnologyJingzhou434020China

Computational Fluid Dynamics is used to assess the thermal(heat transfer)performances of an automobile engine considering different grille opening and closing degrees.For this purpose the entire vehicle is modelled and three fundamental aspects are examined,namely,the open area of the air intake grille,the position of the upper and lower grilles and their shape.The results show that the opening area and position of the grille have some influence also on the aerodynamic characteristics of the automobile.With an increase in the opening angle of the grille,the CD(Drag Coefficient)value of the whole vehicle becomes higher.When the air intake grille of the car is fully open or closed,the CD value is 0.35434 or 0.31777,respectively,that is,the flow resistance in the engine compartment accounts for 10.32%of the CD value for the whole automobile.

关键词： Air intake grille opening and closing degree automobile engine heat transfer function simulation and optimization

Dendrite-free and stable Zn metal anodes with ZnO protective layer

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Science China(Technological Sciences) 2022年第10期65卷 2361-2368页

作者： HOU ZhenHua TAO HuaChao WANG JiaXu ZHANG LuLu YANG XueLin Hubei Provincial Collaborative Innovation Center for new energy Microgrid College of Electrical Engineering&New EnergyChina Three Gorges UniversityYichang 443002China

Metallic Zn can be used as an anode for aqueous zinc-ion batteries due to its low redox potential,rich resources,and high theoretical capacity.However,its practical application is limited by dendrite growth and side reactions.Herein,a simple in-situ growth strategy was applied to fabricate a Zn anode with a ZnO protective layer(Zn/ZnO)to lengthen the cycle life and inhibit the dendrite growth and side reactions.At 1 mA h cm^(−2)capacity,Zn/ZnO exhibits long-time stability(2500 h)at 1 mA cm^(−2)and outstanding rate capability(1000 h at 10 mA cm^(−2))in symmetrical cells.Furthermore,the average coulombic efficiency of the Zn/ZnO//Ti cell is 99.4%,which is desirable at 5 mA cm^(−2).In addition,the Zn/ZnO//MnO_(2)cell can maintain a specific capacity of 167.2 mA h g^(−1)after 800 stable cycles.This work presents a simple fabrication method for Zn anode with excellent performance and suggests the huge possibilities of implementing practically rechargeable aqueous zinc-ion batteries.

关键词： aqueous zinc-ion batteries Zn anode ZnO protective layer dendrite-free

自支撑BiCu/碳杂化纳米纤维膜高效促进CO_(2)电还原生成甲酸

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Science China Materials 2024年第3期67卷 788-795页

作者：宋德文张世鹏宁汇费翔汪明旺王小珊吴文婷赵青山李永哲吴明铂 State Key Laboratory of Heavy Oil Processing College of Chemical EngineeringCollege of New EnergyInstitute of New EnergyChina University of Petroleum(East China)Qingdao 266580China Shandong Dongyue Future Hydrogen energy Material Co. LtdZibo 256412China

二氧化碳电还原有利于二氧化碳高价值利用和间歇性电能的存储,是一种极具应用前景的新技术.自支撑催化剂比粉末催化剂在构建电极方面具有明显优势,但缺乏有效的合成方法.本研究采用电纺丝-碳化法合成了一种自支撑的BiCu/碳杂化纳米纤维... 详细信息

二氧化碳电还原有利于二氧化碳高价值利用和间歇性电能的存储,是一种极具应用前景的新技术.自支撑催化剂比粉末催化剂在构建电极方面具有明显优势,但缺乏有效的合成方法.本研究采用电纺丝-碳化法合成了一种自支撑的BiCu/碳杂化纳米纤维膜(BiCu/CHNM),可直接用作工作电极在流动池中将二氧化碳还原为甲酸盐,其法拉第效率为87.67%,分电流密度为142.9 mA cm^(-2).稳定性测试中,甲酸盐的法拉第效率在高偏电流密度(>100 mA cm^(-2))下可在50小时内连续保持在80%以上.原位拉曼光谱和密度泛函理论计算证实,铜掺杂降低了Bi(012)平面上HCOO~-形成的能垒,同时提高了碳纳米纤维网络的导电性.由于同时具有高导电框架结构和高度分散的BiCu活性位点,这种杂化膜同时表现出高活性、高选择性和长时间稳定性.

关键词： carbon dioxide self-supporting catalyst composite catalyst electroreduction

Effects of the properties of FCCS on the removing of catalyst particles from FCCS under a DC electrostatic field

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Petroleum Science 2023年第3期20卷 1885-1894页

作者： Qiang Li Qing-Zhu Qiu Hao Cao Hui-Zhen Yang Wei-Wei Xu Zhao-Zeng Liu College of New Energy China University of Petroleum(East China)QingdaoShandong 266580China

Catalytic cracking is the main method to lighten heavy crude oil,this process can produce high quality oil products such as gasoline and diesel,but also produces a large amount of fluid catalytic cracking slurry(FCCS).The catalyst particles in FCCS seriously restrict the secondary processing of FCCS and need to be removed,and the properties of Fccs is an important factor that affects the removal efficiency of the catalyst particles.Based on the"effective contact point"model proposed by the research group,this study further proposed the"electrostatic separation efficiency calculation"model.In this model,since Fccs has a uniform distribution of catalyst particles,the ratio of the number of catalyst particles can be expressed as the ratio of area to achieve the calculation of separation efficiency.Then the catalyst removal efficiency under different viscosity was analyzed,thus verifying the feasibility of this model.The effects of temperature and mass ratio of four components on the viscosity of FccS were investigated respectively,then the effects of temperature and four components'mass ratio on the electrostatic sep-aration can be directly converted into the effect of viscosity on the electrostatic separation efficiency.All the results show the electrostatic separation efficiency decreases with increasing viscosity,and the best separationtemperatureis120℃.

关键词： Fluid catalytic cracking slurry(FCCS) Separation efficiency Viscosity Temperature Four components'mass ratio

High Step-up SEPIC Converters Based on a Family of Coat Circuit

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CSEE Journal of Power and energy Systems 2023年第5期9卷 1753-1764页

作者： Binxin Zhu Yu Huang Yao Zhang Guanghui Liu Shihuan Chen the college of Electrical Engineering and new energy China Three Gorges UniversityYichang 443002China

A family of coat circuits for SEPIC converters to improve their boost capability is presented.The present coat circuit does not contain any active switches,so the voltage conversion ratio of the presented converters can be enhanced without complicating its gate driver and control circuits.Meanwhile,because of the expansibility of the coat circuit,the number of its basic cells can be adjusted regarding the actual application requirements.Moreover,in comparison with a conventional SEPIC converter,voltage stress on power switch and diodes of the presented topology is lower at the same output voltage,and thus semiconductor components with low on-resistance are chosen to improve conversion efficiency of converter.The operational principle and steady state analysis of the SEPIC converter with one of the proposed coat circuits have been discussed in detail,and a 300W laboratory prototype is implemented to prove the theoretical analysis of presented converter.

关键词： Coat circuit high voltage gain low voltage stress SEPIC converter