Physical Sciences and Mathematics Commons^™

The Effect Of Interlayer Interactions On The Ferroelectric–Paraelectric Phase Transition In Multilayered Thin Films Of Vinylidene Fluoride–Trifluoroethylene Copolymers, Jihee Kim, Hoydoo You, Stephen Ducharme, Shireen Adenwalla

Stephen Ducharme Publications

The interaction between ferroelectric polymer films with different transition temperatures is evident in the effect of layer thickness on the ferroelectric– paraelectric phase transition in multilayer films, as revealed by x-ray diffraction and dielectric measurements. The multilayer samples consisted of alternating Langmuir–Blodgett (LB) films of two different copolymers of vinylidene fluoride with trifluoroethylene, one with 80% vinylidene fluoride and a ferroelectric–paraelectric transition temperature on heating of 133 ± 4 °C and the other with 50% vinylidene fluoride and a transition temperature of 70 ± 4 °C. Samples with a repeat period of 20 LB layers (10 contiguous layers of each …

Education In The Environment: A Hands-On Student Research And Outdoor Learning Experience: Quarterly Progress Report: Period Ending February 28, 2007, Environmental Education Strategy For Nevada

Reports (PLI Education)

• Forever Earth was scheduled and operated for 21 days; it benefited 398 individuals.
• Newly developed grade 4 activities from the Forever Earth curriculum were field tested.
• Three Discover Mojave Outdoor World events were conducted. A partnership with Big Brothers Big Sisters of Southern Nevada is under development; when finalized, this partnership will markedly increase participation in the program. Similar partnership discussions are also being held with local leadership of the local Boy Scouts of America and Girl Scouts of the USA.
• A work plan has been established for Conservation, Education, and Interpretation Program Manager.
• Cultural Inclusiveness workshops were held in …

Electrochemical Oxidation Of The Phenol In The Chloride System, Yong Liu, Dan Liu, Shi-Lin Zhao, Jing-Jing Lai

Journal of Electrochemistry

The Ru-Ir /Ti electrode as cathode to electrolysis the synthetic phenolic wastewater was studied.The effect of the initial chloride concentration on the electrolytic treatment result has been discussed.Experiment result shows that the electrochemical oxidation of phenol suits to one kinetics equation in given electrolytic time.If the initial chloride concentration in wastewater increases,the time of the electrochemical oxidation of phenol can be shorten,in other words the apparent rate constant is greater.the middle matters of electrochemical oxidation of phenol in the chloride system detected out by HPLC and GC-MS is mainly 1-chloro-phenol,4-chloro-phenol,2,4-dichloro-phenol,2,6-dichloro-phenol,2,4,6-trichloro-phenol,all kinds of chlorohydrin,small aliphatic acid,and so on.The final production is …

Preparation And Lithium Storage Performance Of Nano-Structural Sno_2/Carbon Nanotubes Composite Electrodes, Hong-Bing Wei, Ling Huang, Xiao-Bin Wu, Fu-Sheng Ke, Jin-Shu Cai, Xiao-Yong Fan, Fang-Zu Yang, Shi-Gang Sun

Journal of Electrochemistry

The Nano-structural SnO2/Carbon Nanotubes Composites were prepared in a solution of SnCl2,ethylene glycol(EG),purified MWCNTs and sodium dodecyl sulfate(SDS) at 160 ℃.The phase structure and surface morphology of the composites were measured by XRD HRTEM and SEM.The results indicate that there are high dispersions and high loadings of SnO2 nanoparticles on MWCNTs.Electrochemical lithium storage performance was studied preliminarily on the obtained samples.MWCNTs modified with SnO2 nanoparicles were shown to have a higher electrochemical reversible capacity than that of MWCNTs during the charge and discharge process.MWCNTs can accommodate the larger structure strain of the active materials produced during Li-ion insertion and extraction,which …

Effects Of Direct Current Bias Potentials On Lipid Membranes Forming On A Glassy Carbon Electrode, Yu-Hui Li, Hong-Wei Zhang, Gui-Lan Song, Zhan-Jun Zhang, Sheng-Min Cai

Journal of Electrochemistry

The effects of direct current(DC) bias voltage on the structure of lipid membranes forming on a glassy carbon electrode(GCE) was investigated by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS).The experiment showed that the lipid membranes can be formed with either positive or negative bias potential exerted.When bias voltage was exerted,bilayer lipid membranes tended to form due to the electrostatic interaction between the superficial positive charges on the polarized electrode and the negative charged part of PC.When the positive bias voltage overrun the range,the lacunas on s-BLMs would increase,and the BLMs would be broken.A proper equivalent circuit was nonlinearly fitted,based on the …

Study On The Electrochemical Machining Of Titanium Alloys Tc4 With The Method Of Uniform Design, Mei-Li Zhang, Di Zhu, Zheng-Yang Xu

Journal of Electrochemistry

For the electrochemical machining of titanium alloys,a passivating film tends to form on the machining surface,which holdbacks the process of machining;and some corrosive pittings can appear on the non-machining surface,which leading to the poor surface quality.So how to improve the machining surface quality,this is a hot problem in aerospace industries.An experiment plan has been made with the method of uniform design and the variance analysis has been carried out using the result data of the previous experiments.The experimental results show that an excellent machining surface with Ra 0.38 μm would be obtained in the electrolyte of 10% NaCl solution,4% Na2S2O8 …

Study On The Electrochemical Enhanced Self-Assembled Cobalt-Porphyrin Monolayer, Bei Zhang, Rong Wang, Guo-Yang Zhu, Xiaowei Cao, Xia-Qin Wu, Zong-Rang Zhang, Takeo Ohsaka

Journal of Electrochemistry

According to the different coordination ability between Cobalt(II) porphyrin and Cobalt(Ⅲ) porphyrin,an electrochemical modulated self-assembling process was developed to prepare the CoTMPP/MP/Au(E) modified electrode.The O2 reduction catalytic activity and the Raman spectrum of the CoTMPP/MP/Au(E) modified electrode were found to be similar to those of the CoTMPP/MP/Au(I) modified electrode obtained by the immersion method,which was suggested that both modified electrodes have the similar well oriented structure and electrochemical behavior.Compared with CoTMPP/Au modified electrode,the modified electrodes with mercaptopyridine ligand were showed better electrocatalytic activity and stability.

Composite Electroplating And Characterizations Of Sn-Sba15 Anode For Lithium-Ion Batteries, Xiao-Yong Fan, Jin-Mei Xu, Quan-Chao Zhuang, Hong-Hong Jiang, Ling Huang, Yan-Xia Jiang, Quan-Feng Dong, Shi-Gang Sun

Journal of Electrochemistry

Sn-SBA15 anode was prepared by composite electroplating.The first discharge and charge capacity was 1075mAh/g and 630mAh/g respectively.After fifty charge/discharge cycles,the charge and discharge capacity of Sn-SBA15 were retained above 400mAh/g.XRD patterns indicated that the Sn-SBA15 has tetragonal crystal type.SEM images showed that the Sn-SBA15 had a honeycombed surface.EIS results indicated that there was SEI film formed on the surface of Sn-SBA15 electrode.

The Influence Of Electrolytic Conditions On Synthesis Of Feo_4~(2-), Yan Zhou, Wei-Hua Yang, Dong-Qin Bi, Ting-Ting Huang, Zhen Sun, Quan-Feng Guo

Journal of Electrochemistry

The FeO42-was synthesized using iron lattice as anode and the solid K2FeO4 was also prepared.Influence of electrolytic conditions,such as stir,ultrasonic,temperature and current density on the current efficiency were studied.The results showed that preferable ferrate(VI) current yield was obtained in a current density of 10 mA·cm-2,temperature 30℃ and 14 mol/L NaOH as electrolyte under at stirring effect.

Electrochemical Characteristics Of La_(0.7-X)Ce_Xmg_(0.3)Ni_(2.4)Co_(0.6)(X=0～0.4)Hydrogen Storage Alloys, Ling-Ling Xiao, Yi-Jing Wang, Yi Liu, Jian-Sheng Cao, Da-Wei Song, Li-Fang Jiao, Hua-Tang Yuan

Journal of Electrochemistry

The effect of partial substitution of Ce for La on the structure and the electrochemical properties of the La0.7-xCexMg0.3Ni2.4Co0.6(x=0～0.4)hydrogen storage alloys have been investigated systematically.The result of X-ray powder diffraction(XRD) show that the alloys are all consisted of the LaNi3 phase and the LaNi5 phase.The maximum discharge capacity is decreased gradually with increase of the Ce contents,but the cycling life is improved obviously.

Charge-Discharge Behaviors And Properties Of A Lab-Scale All-Vanadium Redox-Flow Single Cell, Ping Zhao, Hua-Min Zhang, Yue-Hua Wen, Bao-Lian Yi

Journal of Electrochemistry

An experimental setup with two external saturated calomel reference electrodes(SCE)and two flow cells was established for flow battery research application.By using this setup,the cell voltage,potentials and open circuit potentials of the positive and negative electrodes for a lab-scale flow battery single cell,could be determined simultaneously during charge-discharge(C-D) cycle test.Then,the ohmic internal resistance drop(iR drop),overpotentials at the negative and positive electrodes of the cell during C-D process,were calculated.The average iR drop accounts for about 74% of the total voltage losses during the C-D cycle at current density of 60 mA·cm-2,suggesting the voltage efficiency(VE) of vanadium redox-flow battery(VRB) single cell with graphite …

Studies On The Ion Conductive Performance Of Composite Polymer Electrolyte Containing Nano-Scale Sio_2, Lin Ye, Yu-Mei Zhao, Xiao-Wen Zhang, Zeng-Guo Feng, Ying Bai, Feng Wu

Journal of Electrochemistry

Nano-silicon oxide was doped into a novel comblike polyether,poly(3-(methoxy(triethylenoxy))methyl-3'-methyloxetane) to prepare a series of composite polymer electrolyte.The ion conductivity measurement revealed that the composite polymer electrolyte added with 5% weight fraction of SiO2 has the highest ion conductivity of 7.8×10-5 S/cm at 30℃ and 4.5×10-4 S/cm at 80℃,which is increased 30%~60% as compared to the polymer electrolyte without adding any SiO2.DSC results implied that the nano-silicon oxide inserts into the macromolecule chains to increase the free volume and decrease the glass transition temperature to enhance the ion conductivity.In addition,it seems that the crystallization occurred due to the hydrogen bonds between …

Ac Impedance Study On The Bcx Cells, Hong-Hua Ge, Jun Wang, Jing Liu, Guo-Ding Zhou, Yi-Ping Wu, Gang Wu

Journal of Electrochemistry

The electrodes in both Li/SOCl2 cells and BCX cells were studied by ac impedance spectroscopy.The results indicate that the resistance of the electrode passive layer increased with the storage time,then became stabilized in both kinds of cells.But the electrode resistance decreased a lot after adding BrCl into the cells.The resistance of the Li electrode decreased about a half to that without BrCl,and the value of the glassy carbon electrode decreased from about 100 kΩ to 2 kΩ.The huge resistance of the glassy carbon electrode indicates that it is the control electrode of the cell.

Electrochemical Performance Of 1-Ethyl-3-Methylimidazolium Trifluoroacetic To The Electrolyte Of Electrochemical Double Layer Capacitor, Guo-Hua Sun, Kai-Xi Li, Qiang Li, Hui Fan, Jian-Yu Gu

Journal of Electrochemistry

The electrochemical performance of an Electrochemical Double Layer Capacitor consisted of higher specific surface area activated carbon and ionic liquid \CF3COO was investigated by constant current charge/discharge and cyclic voltammegrams(CV) methods.The results indicated that the \CF3COO had High specific capacitance,excellent cyclic characteristics and high charge/discharge efficiency.Specific capacitance of the EDLC increased with electrochemical window increase at the range of steady electrochemical window.Energy density increased with current and voltage increase,power density deduced with current increase but increased with electrochemical window increase.These conclusions revealed that the \CF3COO was very suitable for the electrolyte of EDLC.

Diamond-Like-Carbon Film Prepared On Stainless Steel Substrates By Liquid Phase Electrochemical Deposition, Jing-Yong Du, Gui-Feng Zhang, Guo-Qing Li, Xiao-Duo Hou

Journal of Electrochemistry

Diamond-like carbon(DLC) films were deposited on stainless steel substrates at atmospheric pressure and low temperature(60 ℃) by electrolysis in a methanol solution with a pulseddirect current power supply.The morphology and microstructure of the resulting DLC films were analyzed using atomic force microscopy(AFM)、scanning electron microscopy(SEM)、Raman spectroscopy and Fourier transformation infrared spectrometry(FTIR).The experimental results show that the hydrogenated diamond-like carbon filmsare smooth and compact.Raman spectroscopy analysis confirmed the presence of a strongpeak at 1 332.51 cm-1,which is assigned to crystalline diamond.The deposition rate can be enhanced to 0.5 μm/h by adding hydrogenous organic solutions.

Comparison Of The Electrochemical Reactivity Of Electrodes Modified By Carbon Nanotubes With Different Sizes, Guo-Feng Yang, Neng-Qin Jia, Zhi-Yong Wang

Journal of Electrochemistry

The electrochemical activity of multi-walled carbon nanotubes(MWNTs) with different sizes,including four different MWNTs with the same length and different diameter,two different MWNTs with the same diameter and different length has been assessed and compared.The various MWNTs modified electrodes were prepared by immobilizing the suitable amount of MWNTs onto a glassy carbon electrode,and their voltammetric responses to ferricyanide,uric acid and dopamine were examined.The corresponding cyclic voltammetric data was showed that the electrochemical and electrocatalytic activities are depended on the nanotube length.The electrochemical reactivity of short MWNT(S-MWNT) is better than that of long MWNT(L-MWNT),which may be mainly attributed to the existence of …

Effect Of 2,2€²-Dipyridyl And K_4fe(Cn)_6 On Electroless Copper Plating Using Glyoxylic Acid As Reducing Agent, Dan-Dan Shen, Fang-Zu Yang, Hui-Huang Wu

Journal of Electrochemistry

The electroless copper plating was studied in a bath consisting of glyoxylic acid as reducing agent,Na2EDTA as complexing agent,both 2,2'-dipyridyl and K4Fe(CN)6 as additives,focused on the influence of the additives on the deposition rate,as well as on the composition,structures and surface morphology of the deposits.It was found that adding an optimum amount of 2,2'-dipyridyl and K4Fe(CN)6 to the bath will not only improve the stability of the bath,but also increase the deposition rate by 100 %.The simultaneous addition of both additives causes the deposits to bright appearance and the change in morphology.The deposits were proved to be polycrystalline copper,in which …

Mwnts Modified Gc Electrode For Hydrogen Peroxide Determination, Hong-Juan Wang, Chun-Mei Zhou, Hao Yu, Feng Peng, Jin-Kun Fang

Journal of Electrochemistry

A MWNTs modified GC electrode was constructed successfully to be used to detect hydrogen peroxide.Two methods of maximum anodic current of cyclic voltommogram and chronoamperometry were adopted to measure the concentration of hydrogen peroxide.The results show that the MWCNTs can enlarge the effective surface area of GC electrode and can enormously enhance the electron transfer.The sensitivity and correlation coefficient for hydrogen peroxide detection are 2.84 μA/mmol·L-1,0.997 and 1.5 μA/mmol·L-1,0.971 for cyclic voltammetry and chronoamperometry,respectively.The procedure of the two methods to detect hydrogen peroxide is simple,and the results obtained are satisfied.

Influence Of Electrolyte On The Preparation And Electrocatalytic Properties Of Pt/Gc Electrodes, Sheng-Pei Chen, Yan-Xin Chen, Tao Huang, Xiao-Wen Hou, Shi-Gang Sun

Journal of Electrochemistry

Influence of electrolyte on the electrocatalytic properties of Pt/GC electrodes for formic acid oxidation were studied by using cyclic voltammetry,SEM and electrochemical in situ FTIR spectroscopy.It has demonstrated that the surfaces of Pt/GC electrodes prepared in H2SO4 (Pt/GC1) or in HClO4(Pt/GC2) are all composed of platinum particles,but which crystals are some differences in size and shape.Diameters of platinum particles on the surface Pt/GC1 are of 100~200 nm,and with spheral shape in the majority.The sizes of platinum particles on the Pt/GC2 electrode are larger in general,part of particles is of cube shape and of diameter about 200 nm,and another part of …

Polarization Properties Of The Cu/Paa Composite Films, Li-Chun Zhang, Qing-Shan Li, Meng-Meng Zheng, Fu-Quan Wu

Journal of Electrochemistry

Porous alumina templates with different apertures were fabricated by the pore widening and increase of the anodic oxidation voltage,and then Cu nanowires were synthesized in porous alumina templates by alternating electro-deposition method.The transmission spectrum and polarization spectrum of Cu/PAA composite films were measured.Experiment have indicated that both the pore widening and increase the anodic oxidation voltage can make the transmittance drop,but the pore widening cannot enhance the polarization performance of the micropolarizer.The extinction ratio can be improved with increase of the template oxidation voltage or the Cu nanowires' diameter.

Investigations On Edlcs Using Pmma-Based Gel Polymer Electrolytes, Xiang-Li Meng, Jin-Ling Yin, Juan Ren, Bao-Hong Zhang

Journal of Electrochemistry

Polymethyl methacrylate(PMMA) based gel polymer electrolytes electrochemical double layer capacitors(GPE-EDLCs) were fabricated by an in situ polymerisatonal method with actived carbon electrodes,using propylene carbonate(PC) and ethylene carbonate(EC) as plasticizer,lithion perchlorate as surporting electrolytes.The ion conductivity values of GPEs were evaluated by AC impedance.The properties of PMMA-based GPEs capacitors were researched by impedance spectrum,cyclic voltammetry,galvanostatic charge-discharge.It showed that the ion conductivities of the PMMA-based gel polymer electrolytes reached to 3.7 mS·cm-1 at ambient tempreture.The working voltage of the capacitors reached to 3.0 V.The specific capacitance of the capacitor was obtained as high as 41.6 F·g-1(I=1 mA·cm-2).The equivalent serial resistance of the …

Variable Frequence Switching Power Supply Used To Aluminum Foil Corrosion, Xiang-Dong Zhuo, Lan Sun, Guo-Qing Qian, Chang-Jian Lin

Journal of Electrochemistry

A new variable frequence and multi-wave power supply used to aluminum foil corrosion is introduced.The switching supply power supply controlled by the microcontroller and Variable Frequence in low band and multi-wave、big power supply controlled by the electronic switch bridge for changing phase were designed.This power supply does not need bulky and cumbersome transformer,and the frequency at lower limit is not limited,even lower than 1Hz.

Fabrication And Performance Of Ni-Scsz Cermet Anode Modified By Coating With Gd_(0.2)Ce_(0.8)O_2 For A Sofc, Ren-Zhu Liu, Bo Huang, Xiao-Feng Ye, Shao-Rong Wang, Jia-Di Cao, Huai-Wen Nie, Ting-Lian Wen

Journal of Electrochemistry

A Ni-scandia-stabilized zirconia(Ni-ScSZ) cermet anode modified by coating with nano-sized gadolinium-doped ceria(GDC,Gd0.2Ce0.8O2) was prepared using a simple combustion process for the solid oxide fuel cell(SOFC) running on methane fuel.X-ray diffraction(XRD) and scanning electron microscopy(SEM) indicated that the surface of Ni-ScSZ was coated by nano-sized GDC particles(<100nm).Single cell testing showed that the 2.0%(by mass) GDC-coated Ni-ScSZ anode had better performance.The highest power densities of the cell with this anode were 825 and 848mW/cm2 at 850℃ in humidified hydrogen and methane,respectively,whereas the corresponding values were 584 and 586mW/cm2 for the cell with Ni-ScSZ anode.Electrochemical impedance spectra(EIS) illustrated that the cell with Ni-ScSZ anode exhibited far greater impedances than the cell with 2.0%(by mass) GDC-coated Ni-ScSZ anode.Then the short-term stability for the cells with the Ni-ScSZ and 2.0%(by mass) GDC-coated Ni-ScSZ anodes in 97%CH4/3%H2O at 700℃ was checked over a relative long period of operation.No significant degradation in performance has been observed after 84 h of cell testing when 2.0%(by mass) GDC-coated Ni-ScSZ anode was exposed to 97%CH4/3%H2O at 700 ℃.Very little carbon was detected on the anodes,suggesting that carbon deposition was limited during cell operation.

Trisodium Dicalcium Bismuth Hexaoxide, Irina V. Puzdrjakova, Rene B. Macquart, Mark D. Smith, Hans-Conrad Zur Loye

Faculty Publications

Single crystals of the title compound, Na₃Ca₂BiO₆, were grown from a high-temperature reactive flux solution of Na₂CO₃. Na₃Ca₂BiO₆ crystallizes as an ordered rock-salt structure (space group Fddd), in which the octahedral holes in the oxide array are filled by an ordered 3:2:1 arrangement of Na⁺, Ca²⁺ and Bi⁵⁺ cations. All atoms except for one O atom lie on special positions; site symmetries are as follows: Bi 222, Ca 2, Na 222 and 2, O 2.

Generation Of An On-Capillary Enzyme Reactor Coupled To Capillary Electrophoresis For The Selective Detection Of The Enzyme Substrate, Stephanie Hooper, Mark Anderson

Mark R. Anderson

No abstract is currently available.

Real-Time Divisible Load Scheduling With Different Processor Available Times, Xuan Lin, Steve Goddard, Ying Lu, Jitender Deogun

CSE Technical Reports

Providing QoS and performance guarantees to arbitrarily divisible loads has become a significant problem for many cluster-based research computing facilities. While progress is being made in scheduling arbitrarily divisible loads, some of proposed approaches may cause Inserted Idle Times (IITs) that are detrimental to system performance. In this paper we propose a new approach that utilizes IITs and thus enhances the system performance. The novelty of our approach is that, to simplify the analysis, a homogenous system with IITs is transformed to an equivalent heterogeneous system, and that our algorithms can schedule real-time divisible loads with different processor available times. …

Robert G. Fuller Curriculum Vitae

Robert G. Fuller Publications

Updated through October 2005. Includes Education; Professional Experience; Professional Society Memberships & Honors; Innovative Teaching Activities; External Funding; Refereed Journal Articles (45); Invited Papers (121); Books, Chapters, & Media (87); Abstracts & Proceedings (206).

The Effect Of Cluster Environment On Galaxy Evolution In The Pegasus I Cluster, Lorenza Levy, James A. Rose, Jacqueline H. Van Gorkom, Brian Chaboyer

Dartmouth Scholarship

We present neutral hydrogen observations of 54 galaxies in the Pegasus Cluster. The observations include single-dish H I measurements, obtained with the Arecibo telescope for all 54 galaxies in the sample, as well as H I images obtained with the Very Large Array (VLA) for 10 of these. The Arecibo profiles reveal an overall H I deficiency in the cluster, with similar to 40% of the galaxies in the core of the cluster showing modest deficiencies of typically a factor of 2-3. The HI morphology of so me galaxies shows that the HI disk is smaller than the optical disk …

A 2007 Model Curriculum For A Liberal Arts Degree In Computer Science, Liberal Arts Computer Science Consortium, Charles F. Kelemen

Computer Science Faculty Works

No abstract provided.

Quantized Magnetoresistance In Atomic-Size Contacts, Andrei Sokolov, Chunjuan Zhang, Evgeny Y. Tsymbal, Jody G. Redepenning, Bernard Doudin

Jody Redepenning Publications

When the dimensions of a metallic conductor are reduced so that they become comparable to the de Broglie wavelengths of the conduction electrons, the absence of scattering results in ballistic electron transport and the conductance becomes quantized. In ferromagnetic metals, the spin angular momentum of the electrons results in spin-dependent conductance quantization and various unusual magnetoresistive phenomena. Theorists have predicted a related phenomenon known as ballistic anisotropic magnetoresistance (BAMR). Here we report the first experimental evidence for BAMR by observing a stepwise variation in the ballistic conductance of cobalt nanocontacts as the direction of an applied magnetic field is varied. …