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Guide and control of thermal conduction with isotropic thermodynamic parameters based on a rotary-concentrating device
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作者 刘帽 严泉 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第4期423-429,共7页
A rotary-concentrating device for thermal conduction is constructed to control and guide thermal energy transmitting in elastic plates.The designed device has the ability of concentrating for thermal conduction and co... A rotary-concentrating device for thermal conduction is constructed to control and guide thermal energy transmitting in elastic plates.The designed device has the ability of concentrating for thermal conduction and controlling the processes of thermal diffusion in a plate.The multilayered isotropic material properties of the rotary-concentrating device are derived based on the transformation and rotary medium method and a rotation parameter to control the thermal diffusion process is introduced.The efficiency of the rotary-concentrating device for thermal conduction is verified.Stability of temperature fields in a plate with the rotary-concentrating device is analyzed to study the performance of rotary-concentrating.Numerical examples show that the constructed rotary-concentrating device for thermal conduction can effectively rotate and focus on the thermal energy into the device for a wide range of diffusion temperatures,which can enhance the thermal conduction.Therefore,this study can provide a theoretical support for potential applications in fields of energy harvesting and thermal conduction control. 展开更多
关键词 rotary-concentrating thermal conduction isotropic thermodynamic parameters control of thermal conduction process
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Kinetic Process and Conductivity of Ag^+ Ion Exchange for Polycrystalline Na-β"-Al_2O_3
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作者 Jianhua YANG(Shanghai Institute of Ceramics, Chinese Academy of Scieoces, Shanghai 200050, China) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1996年第4期315-317,共3页
This paper reports the kinetic process of Ag ion exchange for the polycrystalline Na-β'-Al2O3.The interdiffusion coefficients in the process of Ag+ and Na+ ion exchange have been calculated with an 'one dimen... This paper reports the kinetic process of Ag ion exchange for the polycrystalline Na-β'-Al2O3.The interdiffusion coefficients in the process of Ag+ and Na+ ion exchange have been calculated with an 'one dimensional double side diffusion model'. Microstructures of the samples were observed and analysed by XRD, EMPA, SEM. The results of the conductivity measurements for samples with Na+, Ag+ and Na+-Ag+ mobile ions are presented and explained 展开更多
关键词 Kinetic process and Conductivity of Ag Ion Exchange for Polycrystalline Na AL2O3
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Influence of pH on the Property of Apatite-type Lanthanum Silicates Prepared by Sol-gel Process
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作者 施庆乐 张华 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2012年第5期841-846,共6页
The apatite-type lanthanum silicates with formula La9.33Si6O26 are prepared by sol-gel process. The homogeneity of the sol affected by pH value of the solution is investigated. The viscosity of the sols slightly incre... The apatite-type lanthanum silicates with formula La9.33Si6O26 are prepared by sol-gel process. The homogeneity of the sol affected by pH value of the solution is investigated. The viscosity of the sols slightly increases first and then increases abruptly because the predominant reaction mechanism changes from hydrolysis reaction to condensation reaction. In addition, the onset time of the increase for the viscosity shortens from pH 1 to pH 4. The gelation time decreases with increasing pH of the solution. Therefore, the pH of the sols should be less than 4 to form gel. The sol with initial pH 2 shows maximum value of zeta potential and maximum stability. For the sample with initial pH 2, pure apatite-type lanthanum silicates La9.33Si6O26 have been successfully prepared after the dried gel is calcined at 1 000 ℃. In addition, this sample sintered at 1 550 ℃ exhibits the highest ionic conductivity. The activation energies are all less than 0.90 eV. 展开更多
关键词 sol-gel process pH X-ray diffraction ionic conductivity
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Effect of Cu-Excess on the Electrical Properties of Cu_xAlO_2(1≤x≤1.06) 被引量:1
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作者 邓赞红 方晓东 +3 位作者 陶汝华 董伟伟 李达 朱雪斌 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2008年第6期1052-1056,共5页
Cu-excess CuxAlO2 ceramics with delafossite phases were synthesized using sol-gel. In the composition range of 1≤x〈1. 04,there are no detectable non-delafossite phases. Weak diffraction peaks of CuO are observed whe... Cu-excess CuxAlO2 ceramics with delafossite phases were synthesized using sol-gel. In the composition range of 1≤x〈1. 04,there are no detectable non-delafossite phases. Weak diffraction peaks of CuO are observed when x ≥1.04. The room temperature conductivity of the CU1.04AlO2 sample is improved by nearly an order of magnitude over that of the CuAlO2 sample. The major defect mechanism responsible for the conductivity enhancement is proposed to be substitution defects of CuAl (Cu^2 + ions substitute Al^3 + ions). The composition formula unit for Cu-excess Cux AlO2 may be expressed as Cu(All yCuy)O2. 展开更多
关键词 sol-gel processes p-type transparent conducting oxide CuAlO2
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Nanocomposite Membranes based on Perfl uorosulfonic Acid/Ceramic for Proton Exchange Membrane Fuel Cells 被引量:1
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作者 李琼 WANG Guangjin +1 位作者 YE Hong YAN Shilin 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2015年第6期1125-1129,共5页
Perfl uorosulfonic acid/ceramic nanocomposite membranes were investigated as electrolytes for polymer electrolyte membrane fuel cell applications under low relative humidity. Different nanosized ceramics(SiO2, ZrO2, ... Perfl uorosulfonic acid/ceramic nanocomposite membranes were investigated as electrolytes for polymer electrolyte membrane fuel cell applications under low relative humidity. Different nanosized ceramics(SiO2, ZrO2, TiO2) with diameters in the range of 2-6 nm were synthesized in situ in Nafion solution through a sol-gel process and the formed nanosized ceramics were well-dispersed in the solution.The nanocomposite membranes were formed through a casting process. The nanocomposite membrane showes enhanced water retention ability and improved proton conductivity compared to those of pure Nafi on membrane. The mechanical strength of the formed nanocomposite membranes is slightly less than that of pure Nafi on membrane. The experimental results demonstrate that the polymer ceramic nanocompsite membranes are potential electrolyte for fuel cells operating at elevated temperature. 展开更多
关键词 proton exchange membrane ceramic sol-gel process ionic conductivity
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Motor Imagery EEG Fuzzy Fusion of Multiple Classification
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作者 Lu-Qiang Xu Guang-Can Xiao 《Journal of Electronic Science and Technology》 CAS CSCD 2017年第1期58-63,共6页
Due to the volume conduction,electroencephalogram(EEG) gives a rather blurred image of brain activities. It is a challenge for generating satisfactory performance with EEG. This paper studies the multiple areas fusi... Due to the volume conduction,electroencephalogram(EEG) gives a rather blurred image of brain activities. It is a challenge for generating satisfactory performance with EEG. This paper studies the multiple areas fusion of EEG classifiers to improve the motor imagery EEG classification performance. Two feature extraction methods are employed to extract the feature from three different areas of EEG. One is power spectral density(PSD), and the other is common spatial patterns(CSP). Classifiers are designed based on the well-known linear discrimination analysis(LDA). The fusion of the individual classifiers is realized by means of the Choquet fuzzy integral. It is demonstrated that the proposed method comes with better performance compared with the individual classifier. 展开更多
关键词 classifier discrimination satisfactory imagery conduction generating challenge processed projection spatially
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A critical transition rule for broadening exponent of fluctuation and its effect on dissipation in chemical reaction-heat conduction coupling systems
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作者 LIN Feng ZHAO NanRong LUO JiuLi 《Science China Chemistry》 SCIE EI CAS 2011年第5期774-781,共8页
A stochastic model of chemical reaction-heat conduction-diffusion for a one-dimensional gaseous system under Dirichlet or zero-fluxes boundary conditions is proposed in this paper. Based on this model,we extend the th... A stochastic model of chemical reaction-heat conduction-diffusion for a one-dimensional gaseous system under Dirichlet or zero-fluxes boundary conditions is proposed in this paper. Based on this model,we extend the theory of the broadening exponent of critical fluctuations to cover the chemical reaction-heat conduction coupling systems as an asymptotic property of the corresponding Markovian master equation (ME),and establish a valid stochastic thermodynamics for such systems. As an illustration,the non-isothermal and inhomogeneous Schl-gl model is explicitly studied. Through an order analysis of the contributions from both the drift and diffusion to the evolution of the probability distribution in the corresponding Fokker-Planck equation(FPE) in the approach to bifurcation,we have identified the critical transition rule for the broadening exponent of the fluctuations due to the coupling between chemical reaction and heat conduction. It turns out that the dissipation induced by the critical fluctuations reaches a deterministic level,leading to a thermodynamic effect on the nonequilibrium physico-chemical processes. 展开更多
关键词 stochastic model of chemical reaction–heat conduction–diffusion systems stochastic thermodynamics of chemical reaction–heat conduction coupling processes broadening exponent of critical fluctuation entropy production of fluctuations fluctuation–dissipation effect
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Highly conductive,stretchable,durable,skin-conformal dry electrodes based on thermoplastic elastomer-embedded 3D porous graphene for multifunctional wearable bioelectronics 被引量:1
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作者 Shipeng Zhang MdSharifuzzamn +5 位作者 SM Sohel Rana MdAbu Zahed Sudeep Sharma Youngdo Shin Hyesoo Song Jae Yeong Park 《Nano Research》 SCIE EI CSCD 2023年第5期7627-7637,共11页
Long-term bioelectric potential recording requires highly reliable wearable dry electrodes.Laser-induced graphene(LIG)dry electrodes on polyimide(PI)films are difficult to conform to the skin due to the non-stretchabi... Long-term bioelectric potential recording requires highly reliable wearable dry electrodes.Laser-induced graphene(LIG)dry electrodes on polyimide(PI)films are difficult to conform to the skin due to the non-stretchability and low flexibility of PI films.As a result,high interface impedance and motion artifacts can occur during body movements.Transferring LIG to flexible substrates such as polydimethylsiloxane(PDMS)and Ecoflex allows for stretchability and flexibility.However,the transfer process produces a significant loss of conductivity destroying the structural function and electron conduction properties of the LIG.We found robust physical and chemical bonding effects between LIG and styrene-ethylene-butylene-styrene(SEBS)thermoplastic elastomer substrates and proposed a simple and robust low-conductivity loss transfer technique.Successfully embedded LIG onto SEBS to obtain high stretchability,high flexibility,low conductivity losses.Electrophoretic deposition(EPD)of poly(3,4-ethylenedioxythiophene):polystyrenesulfonic acid(PEDOT:PSS)on LIG forms an ultrathin polymer conductive coating.The deposition thickness of the conductive polymer is adjusted by controlling the EPD deposition time to achieve optimal conductivity and chemical stability.SEBS/LIG/PEDOT:PSS(SLPP)dry electrodes have high conductivity(114Ω/Sq),stretchability(300%)and reliability(30%stretch,15,000 cycles),low electrode-skin impedance(14.39 kΩ,10 Hz).The detected biopotential signal has a high signal-to-noise ratio(SNR)of 35.78 dB.Finally,the feasibility of SLPP dry electrodes for long-term biopotential monitoring and biopotential-based human-machine interface control of household appliances was verified. 展开更多
关键词 graphene-embedded elastomers low conductivity loss process highly flexible and stretchable electrophoretic deposition electroencephalography-electrocardiography-electromyography(EEG-ECG-EMG)monitoring
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