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Effect of Ba2+ in BNT ceramics on dielectric and conductivity properties

Natural Science 2010年第4期2卷 357-367页

作者： Konapala Sambasiva Rao kuan china varada rajulu Bollepalli Tilak Anem Swathi 不详

The polycrystalline (Na0.5Bi0.5)1-xBaxTiO3 (x = 0.026, 0.055 & 0.065) (BNBT) ceramics have been synthesized by conventional solid state sinter-ing technique. The tolerance (t) factor of the BNBT composition have been estimated and found to be 0.988, 0.990 and 0.991 for x = 0.026, 0.055 and 0.065 respectively, revealing system is stable perovskite type structure. The com-pound has a rhombohedral-tetragonal Morphtropic Phase Boun- dary (MPB) at x = 0.065. XRD re-sults indicated the crystalline structure of the investigated materials are of single phase with rhombohedral structure and the average parti-cle size of the calcined powder is found to lie between 45 nm - 60 nm. The effect of Ba2+ on dielectric and conductivity properties in Bis-muth Sodium Titanate (BNT) has been studied. The variation of dielectric constant with fre-quency (45 Hz-5 MHz) and temperature (35℃-590℃) has been performed. The value of Tm and Td are found to decrease with increase of concentration of Barium in BNT. The value of tan in the studied materials is found to be the order of 10-2 indicating low loss materials. The evaluated Curie constant in the composi-tion is found to be the order of 105 revealing the materials belong to oxygen octahedra ferro-electrics. The theoretical dielectric data of the studied composition have been fitted by us- ing Jonscher’s dielectric dispersion relation: . The pre-factor a(T), which indicates the strength of the po-larizability showed a maximum at transition temperature (Tm). The exponent n(T) which gives a large extent of interaction between the charge carriers and polarization is found to be minimum in the vicinity of Tm. The A.C. and d.c conductivity activation energies have been eva- luated;the difference in activation energies could be due to the grain boundary effect. The activation enthalpy energies, have been esti-mated and found to be Hm = 0.37 eV, 0.26 eV and 0.25 eV for BNBT-26, BNBT-55 and BNBT-65 re-spectively.

关键词： MPB Dielectric Perovskite Conductivity Tolerance Factor

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Modular assembly of Co4-thiacalix[4]arene units and Keggin-type SiW12O40 for visible-light photothermal conversion

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Tungsten 2025年第1期7卷 112-119页

作者： Jia-Hui Li Qing Zhao Dong-Ao Mao Kun Zhou Bao-kuan Chen Yan-Feng Bi School of Petrochemical Engineering Liaoning Petrochemical University

The construction of metal-organic coordination clusters（MCCs） using modular secondary building units is an important method for preparing functional *** this study,two new MCCs modularly assembled from Keggin-type {SiW12O40}H4TC4A=p-tert-Butylthiacalix[4]arene(SiW12) units and thiacalixarene-supported Co4-thiacalix[4]arene(Co4-TC4A polynuclear second-building units（PSBUs,H4TC4A=p-tert-Butylthiacalix[4]arene） are *** two MCCs,abbreviated as Co4-SiW12and Co8-SiW12,were structurally characterized by single-crystal X-ray *** Co4-SiW12is a supramolecular structure involving cation-anion interactions between Co4-TC4A PSBUs and ***8-SiW12features "barbell-like" shapes with two Co4-TC4A coordinatively linked to a Keggin-type SiW12unit on opposite via W-O_t-Co *** coordination of Co4-TC4A to SiW12in Co8-SiW12resulted in significantly improved photothermal conversion performances compared with Co4-SiW12and pure SiW12or ***-gap determination and photophysical analysis combined with density functional theory calculations indicated the binding mode between Co4-TC4A PSBUs and SiW12,which considerably influences the way of electron transport and the conversion ability of visible light to heat.

关键词： Modular construction Photothermal conversion Polyoxometalate Thiacalixarene

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Innovative dual-mode device integrating capacitive desalination and solar vapor generation for high-efficiency seawater desalination

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Journal of Energy Chemistry 2025年第1期100卷 171-179页

作者： Jiacheng Wang Zhaoyu Chen Ruduan Yuan Jiaxin Luo Ben Zhang Keju Ji Meng Li Juanxiu Xiao kuan Sun National Innovation Center for Industry-Education Integration of Energy Storage Technology MOE Key Laboratory of Low-grade Energy Utilization Technologies and SystemsCollege of Energy & Power Engineering Chongqing University Xuefeng Mountain Energy Equipment Safety National Observation and Research Station CQU-NUS Renewable Energy Materials & Devices Joint Laboratory Chongqing University Southwest Technology and Engineering Research Institute Jiangsu Provincial Key Laboratory of Bionic Functional Materials College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics State Key Laboratory of Marine Resources Utilization in South china Sea Collaborative Innovation Center of Marine Science and Technology School of Marine Science and Engineering Hainan University

Solar-driven interface evaporation with high solar-to-steam conversion efficiency has shown great potential in seawater ***,due to the influence of latent heat and condensation efficiency,the water yield from solar-driven interface evaporation remains insufficient,posing a significant challenge that requires *** this work,we designed a dual-mode high-flux seawater desalination device that combines solar-driven interface evaporation and capacitive *** utilizing coupled desalination materials exhibiting both photothermal conversion and capacitance activity,the device demonstrated photothermal evaporation rates of 1.41 and 0.97 kg m-2h-1for condensate water yield under one-sun ***,the device exhibited a salt adsorption capacity of up to48 mg g-1and a salt adsorption rate of 2.1 mg *** addition,the salt adsorption capacity increased by approximately 32% under one-sun ***,photo-enhanced capacitive desalination performance was explored through numerical simulations and theoretical *** calculations and characterizations confirmed that the defect energy levels formed by the introduction of sulfur vacancies can effectively widen the light absorption range,improve photothermal conversion performance,and stimulate more photoelectrons to participate in capacitive ***,the electron distribution state of molybdenum disulfide with sulfur vacancies and surface defect sites contributes to ion/electron transport at the solid-liquid *** work provides a novel pathway for integrating solar vapor generation with other low-energy desalination technologies.

关键词： Desalination

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Design of a terahertz slotted waveguide array antenna based on photonic crystal

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Optoelectronics Letters 2025年

作者： PAN Wu YE kuan ZHANG Zhen LI Renpu QIU Sen HUANG Lei College of Photoelectronic Engineering， Chongqing University of Posts and Telecommunications Chongqing Municipal Key Laboratory of Photoelectric Information Sensing and Transmission Technology， Chongqing University of Posts and Telecommunications Laboratory of Quantum Information Technology， Chongqing University of Posts and Telecommunications

In this paper， a terahertz slotted waveguide array antenna is designed based on photonic crystal， which can realize efficient radiation of terahertz waves. The electromagnetic wave is fed from the rectangular waveguide at the bottom of the antenna， coupled to photonic crystal waveguide through photonic crystal cavity， and radiated outward through slots at the top layer of antenna. The simulation results show that the antenna achieves a peak gain of 13.45dBi at 360 GHz， a half-power beamwidth of 10.9o， and a side lobe level of -13.9dB. The antenna based on photonic crystal has the advantages of low profile， low loss， and high radiation efficiency， which can be applied to terahertz wireless communication systems.

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Enhancement of Metastatic and Invasive Capacity of Gastric Cancer Cells by Transforming Growth Factor-β1

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Acta Biochimica et Biophysica Sinica 2006年第3期38卷 179-186页

作者： kuan-Song WANG Central South University Changsha 410013 china Department of Pathology Basic School of Medicine

Transforming growth factor-β (TGF-β),a multifunctional cytokine,exerts contradictory rolesin different kinds of cells.A number of studies have revealed its involvement in the progression of many typesof *** investigate the effect of TGF-β on gastric carcinoma,SGC7901,BGC823 and MKN28 (aTGF-β-resistant cell line) adenocarcinoma clones were *** pretreatment in serum-free medium withor without 10 ng/ml TGF-β1,their experimental metastatic potential,chemotaxis,and invasive and adhesiveability were ***,zymography for gelatinase was *** colonies were alsomeasured 4 weeks after inoculation of SGC7901,BGC823 and MKN28 in Balb/c nude mice,and an increasein the number of surface liver metastases was seen in SGC7901 (from 11.0±3.0 to 53.3±3.3) and BGC823(from 9.3±2.5 to 60.0±2.8) groups,whereas there was no difference between MKN28 groups (from 35.2±3.8 to 38.5±2.7).In vitro experiments showed that TGF-β1 increased the adhesion capacity of SGC7901and BGC823 cells to immobilized reconstituted basement membrane/fibronectin matrices and promoted theirpenetration through reconstituted basement membrane *** demonstrated that enhancedinvasive potential was partly due to the increased type Ⅳ collagenolytic (gelatinolytic) activity,but there wasno difference in type Ⅳ collagenolytic activity and other biological behaviors between MKN28 *** suggested that TGF-β1 might modulate the metastatic potential of gastric cancer cells by promotingtheir ability to break down and penetrate basement membrane barriers and their adhesive and motile *** speculated that TGF-β1 might act as a progression-enhancing factor in gastric *** blockageof TGF-β or TGF-β signaling might prevent gastric cancer cells from invading and metastasizing.

关键词： gastric cancer transforming growth factor-β invasion metastasis

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Studies on the Electrochemistry of Dopamine at a Pyrocatechol Sulfonephthalein Modified Glassy Carbon Electrode

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Chemical Research in Chinese Universities 2000年第1期16卷 42-48页

作者： CAI Chen-xin and XUE kuan-hong (Department of Chemistry, Nanjing Normal University, Nanjing 210097, P. R. china) 南京师范大学江苏南京 210097

The electrochemical response of dopamine(DA) at a pyrocatechol sulfonephthalein modified glassy carbon(PS/GC) electrode is reported. The electrode can be used as a detector for the determination of dopamine with a high stability and a good sensitivity. The cyclic voltammetric results indicated that there was a couple of well-defined redox peaks for dopamine at the PS/GC electrode with E_(pa)= 220 mV, E_(pc)=95 mV and the formal potential E^(o')= 157. 5 mV(vs. SCE) at 100 mV/s in the buffer solution of pH 7. 0. The PS/GC electrode can also be used to separate the electrochemical responses of ascorbic acid and DA by 54 mV with the differential pulse voltammetry. Under the selected conditions, the oxidation peak currents are linear with DA concetration in the range of 5. 0 × 10^(-6) to 5. 0 × 10^(-4) mol/L, and the detection limit is 1. 0 ×10^(-6) mol/L at S/N=3. Normalized with concentration, the relative sensitivity of dopamine to ascorbic acid reaches ca. 30. 8: 1.

关键词： Chemically modified electrode Neurotransmitter Dopamine Ascorbic acid Pyrocatechol sulfonephthalein

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Wavelet Energy Feature Extraction and Matching for Palmprint Recognition

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Journal of Computer Science & Technology 2005年第3期20卷 411-418页

作者： Xiang-QianWu kuan-QuanWang DavidZhang SchoolofComputerScienceandTechnology HarbinInstituteofTechnologyHarbin150001P.R.China BiometricsResearchCentre DepartmentofComputingHongKongPolytechnicUniversity

According to the fact that the basic features of a palmprint, includingprincipal lines, wrinkles and ridges, have different resolutions, in this paper we analyzepalmprints using a multi-resolution method and define a novel palmprint feature, which calledwavelet energy feature (WEF), based on the wavelet transform. WEF can reflect the wavelet energydistribution of the principal lines, wrinkles and ridges in different directions at differentresolutions (scales), thus it can efficiently characterize palmprints. This paper also analyses thediscriminabilities of each level WEF and, according to these discriminabilities, chooses a suitableweight for each level to compute the weighted city block distance for recognition. The experimentalresults show that the order of the discriminabilities of each level WEF, from strong to weak, is the4th, 3rd, 5th, 2nd and 1st level. It also shows that WEF is robust to some extent in rotation andtranslation of the images. Accuracies of 99.24% and 99.45% have been obtained in palmprintverification and palmprint identification, respectively. These results demonstrate the power of theproposed approach.

关键词： biometrics palmprint recognition wavelet energy feature weighted cityblock distance

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THE　LINEAR　SEPARATED　FLOW　MODEL　FOR　TWO－PHASI　FLOW　INSTABILITY　IN　BOILING　CHANNELS

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Journal of Hydrodynamics 1996年第2期8卷 9-16页

作者： Zhou Yun-long Shen Zeng-ming Shi Hui-xian(Northeast china Institute of Electric Power Engineering, Jilin 132012, P. R. china)Chen Ting-kuan Chen Xue-jun(Xi’an Jiaotong University, Xi’an 710049, P. R. china) Northeast china Inst of Electric Power Engineering Jilin China

This paper presents linear separated model describing two-phase now instability. By employing the method of separated model and system control theory, dynamic system characteristic equations of describing two-phase flow instability are *** can be decided system stability depending on the characteristic value of characteristic equations. The calculated results agree well with the experimental data.

关键词： evaporated tube vapor-liquid two-phase flow instability separated Model

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The Cellular Automata Model of Electroslag Remelting Ingot Structure

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Journal of Iron and Steel Research International 2011年第S2期18卷 159-165页

作者： LI Bao-kuan, WANG Fang, ZHANG He, CHEN Ming-qiu (College of Materials and Metallurgy, Northeastern University,Shenyang 110819, Liaoning, china) Northeastern Univ Coll Mat & Met Shenyang 110819 Liaoning Peoples R China

Electroslag remelting (ESR) is an advanced process for the production of high quality steels. The microstructure of remelted steel which affect the mechanical properties and the performance of the ingot was determined by the technological parameters. A two-dimensional axisymmetric geometry which was established in this paper was divided into macro-grid finite element in order to compute temperature field; then the grid was divided into more detailed and uniform cells, and at last the continuous nucleation model based on the Gaussian distribution and KGT growth model was established for nucleation and growth calculations using cellular automaton method (CA) on the solidification of molten steel. The results show that: a vertical columnar grain zone and a inverted V-shaped columnar crystal zone appeared in the ESR ingot. In addition, the temperature field with different electrode melting rate and slag pool temperature parameters and the microstructure with different average nucleation under cooling and maximum grain density were studied in this paper. The simulation results agree well with the experimental results, so it is proved that the model and calculation method is reliable. To produce ideal solidified ingot and achieve the purpose of optimizing the production process, the production process was adjusted according to the simulation results.

关键词： electroslag remelting numerical simulation microstructure cellular automata

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Chromo-chemodosimetric detection for Fe^(2+) by Fenton reagent-induced chromophore-decolorizing of halogenated phenolsulfonphthalein derivatives

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Science china Chemistry 2010年第6期53卷 1398-1405页

作者： ZHENG kuan,LAI ChengYue,HE LiPing & LI Fang Key Laboratory of Green Chemistry and Technology,Ministry of Education College of Chemistry,Sichuan University,Chengdu 610064,china Key Laboratory of Green Chemistry and Technology Ministry of Education College of Chemistry Sichuan University Chengdu China

A commercially-available sulfonphthalein derivative was demonstrated to be a chemodosimeter for Fe2+ and its sensing behavior was further investigated by UV-vis spectroscopy in aqueous media under the optimum *** the presence of chlorophenol red (CPR) and H2O2,the absorption maximum at 435 nm decreased upon addition of Fe2+,resulting in a significant color change of the CPR solution from yellow to *** chemosensor system did not show significant responses to a series of other metal ions including Al3+,Zn2+,Cd2+,Hg2+,Mn2+,Co2+,Fe3+,Ni2+,Cu2+,La3+,Ce4+,Th4+,Pd2+,Pb2+,Sb3+,Cr3+,Au3+,Ag+,Nd3+,Sm3+,alkali and alkaline earth metal cations,allowing for highly selective naked-eye detection of Fe2+.Quantitative analysis was carried out kinetically for practicable the Fe2+ assay when either fixed time method or the initial rate method was *** the detecting time was set,the decrease of absorbance signal was linear with Fe2+ concentration in the range of 0 to 7.50 × 10-5 mol L-1 and the regression equation was ΔA = 0.00759 + 0.00593CFe with a correlation coefficient r = *** chemodosimetric system has employed an irreversible Fenton reagent-promoted oxidation of the CPR free chromophore and the hydroxyl radicals were generated in the presence of both Fe2+ and hydrogen *** mechanistic interpretation of the signaling process was partially confirmed by the radical scavenging experiment and the FT-IR analysis of the intermediates formed at different reaction periods.

关键词： colorimetric chemosensor ferrous ion sulfonphthalein Fenton reagent

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