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Articles 26191 - 26220 of 36915

Full-Text Articles in Physical Sciences and Mathematics

Preparation And Electrochemical Capacitance Of Spherical-Like Polypyrrole Doped With Heparin Sodium, Hong-Yu Mi, Xiao-Gang Zhang, Su-Dong Yang, Xiang-Guo Ye May 2008

Preparation And Electrochemical Capacitance Of Spherical-Like Polypyrrole Doped With Heparin Sodium, Hong-Yu Mi, Xiao-Gang Zhang, Su-Dong Yang, Xiang-Guo Ye

Journal of Electrochemistry

Spherical-like polypyrrole with an average diameter of 100 nm as the electrode material for supercapacitor was prepared by a self-assembly process with heparin sodium salt as the dopant at-10 ℃.The morphology and electrochemical properties were characterized by transmission electron microscopy(TEM),cyclic voltammetry(CV),galvanostatic charge/discharge and electrochemical impedance spectroscopy(EIS) measurements.The results showed that the polypyrrole doped with heparin sodium salt exhibited good capacitive behavior.The specific capacitance of single electrode was up to 338 F/g at 3 mA/cm2.

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Inhibition Of Amino Acids Against Steel In Hydrochloric Acid Solution, Ming-Yan Cheng, Wei-Ming Wu, He-Ming Liu, Hai-Yan Du May 2008

Inhibition Of Amino Acids Against Steel In Hydrochloric Acid Solution, Ming-Yan Cheng, Wei-Ming Wu, He-Ming Liu, Hai-Yan Du

Journal of Electrochemistry

The inhibition effect of glutamic acid towards the corrosion of X65 steel in hydrochloric acid solution(10%) was investigated using polarization techniques、electrochemical impedance spectroscopy(EIS) and SEM.The corrosion rate,corrosion potential(Ecoor),polarization resistance(Rp) and inhibition efficiency(η) were determined.The results revealed that the inhibitor is a mixed type inhibitor.It has promising corrosion inhibition efficiency at low concentrations.The inhibition efficiency(η) increased with increasing the concentration.The maximum inhibition efficiency appeared at 0.3 g·L-1.

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Property Of Organic Electrolyte In V_2o_5/C Electrochemical Capacitor, Hong Wang, Zhi-Yuan Tang, Zhong-Yan Li, Xin-Guo Zhuang May 2008

Property Of Organic Electrolyte In V_2o_5/C Electrochemical Capacitor, Hong Wang, Zhi-Yuan Tang, Zhong-Yan Li, Xin-Guo Zhuang

Journal of Electrochemistry

In this work,the V2O5 cathode and graphite anode were assembled into non-symmetric electrochemical capacitors using 1.0 mol/L LiClO4 /(EC + DMC),1.0 mol/L LiPF6 /(EC + DEC + DMC),and 1.6mol/L Et4NBF4/AN as electrolyte,respectively.Charging and discharging tests,Cyclic Voltammetry and AC impedance methods were used to investigate the performance of the non-symmetric electrochemical capacitors.The results showed that the electrolyte 1.0 mol/L LiClO4/(EC+DMC)displayed better cycling performance and less resistance.At the current density of 500 mA/g,its specific energy reached 8.4 Wh/kg and the charge-discharge efficiency was 98%.

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Electrocatalytic Performance Of Pt/C And Pt/Wo_3/C Catalysts For Methanol Oxidation, Yuan-Yuan Chu, Bing Wu, Ya-Wen Tang, Tian-Hong Lu, Ying Gao May 2008

Electrocatalytic Performance Of Pt/C And Pt/Wo_3/C Catalysts For Methanol Oxidation, Yuan-Yuan Chu, Bing Wu, Ya-Wen Tang, Tian-Hong Lu, Ying Gao

Journal of Electrochemistry

The catalysts of Carbon supported Pt(Pt/C) and carbon supported Pt/WO3(Pt/WO3/C) were prepared with liquid phase reduction method.It was found that the catalytic activity and stability of the Pt/WO3/C catalysts were increased with the addition of WO3.When the atomic ratio of Pt and W was 1∶1,the best electrocatalytic performance of the Pt/WO3/C catalyst for the methanol oxidation was obtained.This is attributed to the larger electrochemical surface area of Pt/WO3/C and the weeker adsorption of CO towards the catalyst.

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Electrochemical Performances Of Copper/Activated Carbon Composites, Lan-Ting Li, Qiang Xie, Wen Yan, Yan-Yan Wang, Wen-Wen Xing May 2008

Electrochemical Performances Of Copper/Activated Carbon Composites, Lan-Ting Li, Qiang Xie, Wen Yan, Yan-Yan Wang, Wen-Wen Xing

Journal of Electrochemistry

The development and improvement of electrode materials can result in the enhancement of the performances of electrochemical capacitor.In this paper various copper/activated carbon composites were prepared in the presence of different amounts(from 0% to 40%) of copper nitrate from bituminous coal.Then different electrodes were prepared from copper oxide,activated carbon and copper/activated carbon composites,respectively,and were characterized by cyclic voltammetry,alternative current(AC) impedance,charge-discharge at constant current and maintenance of the self-potential.The results showed that the proper amount of copper in copper/activated carbon composites positively influenced the electrochemical performances of electrodes,and the capacitance of copper/activated carbon composites was larger than that of the total …

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Influence Of Assembly Force In A Pemfc Under A Lifetime Test, Fan Xu, Xuan Cheng, Ying Zhang, Qin-Bai Fan May 2008

Influence Of Assembly Force In A Pemfc Under A Lifetime Test, Fan Xu, Xuan Cheng, Ying Zhang, Qin-Bai Fan

Journal of Electrochemistry

The lifetime performance was investigated by assembling the single cell of PEMFC under a series of holding forces ranging from 0.45 to 11.3 MPa and reassembled under optimal holding force.The polarization and power density curves were obtained during different periods of operating time up to 2000 hours and the fuel cell catalyst activation regions in the polarization curves were analyzed to evaluate the electrochemical kinetic parameters.The results revealed that the holding forces affected not only the internal contact resistances,but also the kinetic parameters which might be caused by the change of the MEA microstructures.The apparent degradation observed at higher current …

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Preparation Of Zn-Ni Alloy Whisker By Electrochemical Method, Zhen-Hai Liang, Xi-Hua Xia May 2008

Preparation Of Zn-Ni Alloy Whisker By Electrochemical Method, Zhen-Hai Liang, Xi-Hua Xia

Journal of Electrochemistry

The Zn-Ni alloy whiskers were prepared by electrochemical method and were characterized by XRD、SEM and EDS methods.The results showed that Ni5Zn21 and Ni3Zn22 whiskers were obtained with the length of 2~4 μm and the diameter of 250 nm,thereby the rations of length/diameter fell between 8 and 16.The electrochemical behavior was investigated by cyclic voltammetry method simultaneously.A new method was provided on whisker preparation based on this work.

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Synthesis Of Agv_3o_8 As High-Capacity Of Cathode Materials For Lithium Secondary Batteries Via A Soft Chemistry Technique, Xiao-Yu Cao, Tao Li, Ling-Ling Xie, Xiang-Yang Yan, Chi-Wei Wang May 2008

Synthesis Of Agv_3o_8 As High-Capacity Of Cathode Materials For Lithium Secondary Batteries Via A Soft Chemistry Technique, Xiao-Yu Cao, Tao Li, Ling-Ling Xie, Xiang-Yang Yan, Chi-Wei Wang

Journal of Electrochemistry

The layered cathode material of AgV3O8 has been prepared for the lithium secondary batteries via the soft chemistry technique. The so-synthesized powders were characterized by XRD(powder X-ray diffraction),SEM(scanning electron microscope) and LPSA(laser particle size analysis).The electrochemical property was investigated by the galvanostatic discharge-charge technique.The results indicated that the particale sizes of AgV3O8 prepared were small in the distribution of narrow range,which leads to high discharge capacity.Among them,the material synthesized at 400 ℃ displayed the first discharge capacity of 760.5 mAh/g.

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The Effect Of Annealed Temperature On Properties Of Ru-Ir-Sn Oxide Anode Coatings, Lei Ji, Jun-Tao Wang, Li-Kun Xu, Wen-Bin Liu, Gui-Lin Xue May 2008

The Effect Of Annealed Temperature On Properties Of Ru-Ir-Sn Oxide Anode Coatings, Lei Ji, Jun-Tao Wang, Li-Kun Xu, Wen-Bin Liu, Gui-Lin Xue

Journal of Electrochemistry

The anode coatings of Ru-Ir-Sn oxide were prepared by sol-gel method with different annealed temperatures.The influences of annealed temperature in properties of anode coatings were characterized by scanning electron microscope(SEM),energy dispersive X-ray detector(EDX),X-ray diffraction(XRD),potential of chlorine evolution,accelerated life,cyclic voltammetry and electrochemical impedance spectroscopy(EIS) tests.The results showed that the annealed temperature affected the morphology of coatings,while the electric quantities of cyclic voltammetry and double layer capacitances of anode coatings had a tendency to fall down and the potential of chlorine evolution and accelerated life had a tendency to increase as the annealed temperature increased.

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Preparation And Photoelectrochemical Properties Of Fe-Doped Tio_2 Nanotube Arrays, Jing Li, Lan Sun, Hui-Fang Zhuang, Cheng-Lin Wang, Rong-Gui Du, Chang-Jian Lin May 2008

Preparation And Photoelectrochemical Properties Of Fe-Doped Tio_2 Nanotube Arrays, Jing Li, Lan Sun, Hui-Fang Zhuang, Cheng-Lin Wang, Rong-Gui Du, Chang-Jian Lin

Journal of Electrochemistry

The Fe-doped TiO2 nanotube arrays were fabricated in Fe(NO3)3-HF mixing solutions by electrochemical anodic oxidation method,and characterized by FESEM,Raman,XPS and DRS.The effect of Fe concentratiions on photoelectrochemical property of the arrays was also investigated.The diameters and lengths of Fe-doped TiO2 nanotube arrays were 50~90 nm and about 200 nm,respectively.Compared with the undoped TiO2 nanotube arrays,the absorption edge of Fe-doped TiO2 nanotube arrays appeared red shifting.The more Fe content,the larger red shifting,in addition,the photocurrent of Fe-doped TiO2 nanotube arrays increased obviously.

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Cyclic Voltammetry And In Situ Ftir Studies Of Cyanide Adsorption On Nanostructured Au Film Electrode In Alkaline Solutions, Chun-Hua Zhen, Chun-Jie Fan, Shi-Gang Sun May 2008

Cyclic Voltammetry And In Situ Ftir Studies Of Cyanide Adsorption On Nanostructured Au Film Electrode In Alkaline Solutions, Chun-Hua Zhen, Chun-Jie Fan, Shi-Gang Sun

Journal of Electrochemistry

The adsorption of cyanide(CN-) on electrodes of nanometer scale thin film of gold supported on glassy carbon(nm-Au/GC) in alkaline solutions were investigated using cyclic voltammetry and in situ FTIR spectroscopy.It has revealed that the electrodeposited nanostructured Au thin film exhibited AIREs(abnormal infrared effects) for CN-adsorption,which manifested 3 nonlinear IR spectral features: inversion of the direction of CN-band,enhancement of IR absorption of adsorbed CN-species(about 39.2 folds) and increase in the FWHM(full width at half maximum) of CN-band.

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Direct Electrochemistry Of God On Glassy Carbon Electrode Modified With Mesoporous Carbon, Kun-Qi Wang, Lin Zhu, Wei Xing May 2008

Direct Electrochemistry Of God On Glassy Carbon Electrode Modified With Mesoporous Carbon, Kun-Qi Wang, Lin Zhu, Wei Xing

Journal of Electrochemistry

Glucose oxidase(GOD) is immobilized on glassy carbon electrode mesoporous carbon by simple method.Cyclic voltammetric results indicated that on GOD of the modified electrode a quasi-reversible redox reaction took place(GCE) surface modified at a formal potential of-0.4294 V in 0.1 mol/L phosphate buffer solution(PBS)(pH 7.1).The electrochemical reaction consisted of a two-electron transfer coupled with a two-proton transfer.The GOD can completely catalyze oxidation of glucose via electron transfer intermedia of ferrocene monocarboxylic acid(FMCA) in saturated solutions with N2.The bioactivity of GOD on the modified electrode with mesoporous carbon was obviously unattacked.

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Electrochemical Performance Of C-Lifepo_4 By Polyaniline Doping, Wei Wang, Li-Fang Jiao, Hua-Tang Yuan May 2008

Electrochemical Performance Of C-Lifepo_4 By Polyaniline Doping, Wei Wang, Li-Fang Jiao, Hua-Tang Yuan

Journal of Electrochemistry

The olivine LiFePO4 cathode materials were synthesized using the solid state method in an inert atmosphere by doping polyaniline into the C-LiFePO4.It was found that the electrochemical performance of polyaniline-doped C-LiFePO4 slightly improved.At a low discharging rate(0.1C), the capability of(C-LiFePO4)0.9(PANI)0.1 reached 164 mAh·g-1.When the charge-discharge rate is increased to 0.5C and 1.0C,the showed capacities of 121.6 mAh·g-1 and 110.1 mAh·g-1 were obtained,respectively.

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Preparation And Catalytic Activity Of Nanostructured Pd And Au-Pd Thin Films, Cui-Cui Qiu, Jin-Tao Zhang, Fang Tian, Hou-Yi Ma May 2008

Preparation And Catalytic Activity Of Nanostructured Pd And Au-Pd Thin Films, Cui-Cui Qiu, Jin-Tao Zhang, Fang Tian, Hou-Yi Ma

Journal of Electrochemistry

The nanostructured Pd thin films were directly formed on the glassy carbon electrode(GCE) substrates by using potential cycling method.The as-prepared Pd thin films deposited onto the GCE were able to absorb enough amount of hydrogen in acidic solutions at the cathodic potentials more negative than the hydrogen evolution potential.Moreover,the absorbed hydrogen could be used as the reducing agent to reduce gold(III) ions to Au nanoclusters,thereby forming bimetallic Au-Pd thin films on the GCE substrate.SEM and cyclic voltammetry characterization demonstrated that the Au-Pd thin films display much higher catalytic activity towards the electro-oxidation of ethanol than the pure Pd thin films.

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Structure And Property Of Molecular Self-Assembled Membrane With Zirconium Ion, Tian-De Wang, Rong Wang, Xia-Qin Wu, Zhi-Gang Guo, Wei-Wei Ji May 2008

Structure And Property Of Molecular Self-Assembled Membrane With Zirconium Ion, Tian-De Wang, Rong Wang, Xia-Qin Wu, Zhi-Gang Guo, Wei-Wei Ji

Journal of Electrochemistry

According to the complex interaction between dodecyl phosphonate and stainless steel surface as well as the zirconium ion,the self-assembled monolayer and double-layer dodecyl phosphonate modified 304 type stainless steel electrode were prepared.The electrodes were characteristiced by static contact angles and electrochemical polarization methods.The results suggested that the double-layer modified stainless steel electrode had better corrosion inhibition effect than the monolayer modified electrode.

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Passivation Behaviors Of Mo,W Electrodes In Mgcl_2-Kcl-Nacl-Cacl_2 Molten Salt For Electrolysis Of Magnesium, Chen Ye, Ye Ke May 2008

Passivation Behaviors Of Mo,W Electrodes In Mgcl_2-Kcl-Nacl-Cacl_2 Molten Salt For Electrolysis Of Magnesium, Chen Ye, Ye Ke

Journal of Electrochemistry

The discharge process and passivation behaviors of Mg(Ⅱ) on cathode(Mo、W) in MgCl2-KCl-NaCl-CaCl2 molten salt system had been investigated by means of cyclic voltammetry and chronoamperometry.The composition of molten salt was MgCl(10%)+CaCl(20%)+NaCl(60%)+KCl(10%)(by mass) and the temperature of electrolysis was 725 ℃.The deposition potential of Mo was 37 mV more negative than that of W,while the peak current was sharper than Mo according to the voltammograms at 0.05 V/s,indicating that the passivation on Mo cathode is easier than W.The formation of MgO impurities during the electrolysis could cause the cathode passiration.However,the reversibility on the discharge reaction of W cathode was better than …

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Quick Tester With Usb Interface For The Corrosion Protection Properties Of Organic Coating, Xiang-Dong Zhuo, Chang-Jian Lin May 2008

Quick Tester With Usb Interface For The Corrosion Protection Properties Of Organic Coating, Xiang-Dong Zhuo, Chang-Jian Lin

Journal of Electrochemistry

According to the principle of multiple dynamic potential scaning polarization,a quick tester with USB interface for the fast study of corrosion resistance properties of organic coating/ metal system has been developed.This tester is portable,facile,practical,and has a strong function for data collection and data treatment.It is not only suitable for the accelerated test in laboratory,but also for the quick test and evaluation to the corrosion resistance of the organic coating/metal system in industrial spots.

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Synthesis And Electrochemical Characteristics Of Li[Li_(0.167)Mn_(0.583)Ni_(0.25)]O_2 Cathode Material, Ling-Yan Yu, Wei-Hua Qiu, Fang Lian, Jia-Yuan Huang, Xao-Li Kang, Wei Liu May 2008

Synthesis And Electrochemical Characteristics Of Li[Li_(0.167)Mn_(0.583)Ni_(0.25)]O_2 Cathode Material, Ling-Yan Yu, Wei-Hua Qiu, Fang Lian, Jia-Yuan Huang, Xao-Li Kang, Wei Liu

Journal of Electrochemistry

The cathode material of Li[Li0.167Mn0.583Ni0.25]O2 was synthesized by low-heat solid state reaction.The results of XRD and FESEM indicated that the powders of the material were well crystallized with the uniform diameters ranging from 60 nm to 100 nm and could be indexed as α-NaFeO2 structure(R3-m space).Galvanostatic charge-discharge tests showed that the electrode delivered the capacity of about 120 mAh/g with good cyclability when cycled in 2.5~4.4V at 0.5C.When the cut-off potential was set up to 4.6V,the cathode delivered much larger capacities with the maximum of 234 mAh/g.It was observed that the discharge capacity gradually increased with the increment of the …

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Effect Of Mn~(2+) Doping On The Electrochemical Performance Of Licopo_4, Huan-Huan Li, Xiao-Liang Yang, Jin-Ping Wei, Zhen Zhou, Jie Yan May 2008

Effect Of Mn~(2+) Doping On The Electrochemical Performance Of Licopo_4, Huan-Huan Li, Xiao-Liang Yang, Jin-Ping Wei, Zhen Zhou, Jie Yan

Journal of Electrochemistry

Undoped and Mn-doped LiCoPO4 cathode materials were synthesized via a novel sol-gel route.The effects of Mn doping on the structure,morphology and electrochemical performance of the LiCo1-xMnxPO4 cathode material were investigated.X-ray diffraction analysis indicated that the olivine structure of the LiCo1-xMnxPO4 composite was well maintained after the doping of a small quantity of Mn2+.The LiCo0.99Mn0.01PO4 cathode material exhibited optimal electrochemical performance with a discharge capacity of 130.6mAh/g at 0.1C rate.

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Electroless-Deposition Synthesis Of Highly Active Ptru/C And Ptrusn/C As Anode Catalysts For Defc, Jing Zhu, Yi Su, Hua Ma, Fang-Yi Cheng, Zhan-Liang Tao, Jing Liang, Jun Chen May 2008

Electroless-Deposition Synthesis Of Highly Active Ptru/C And Ptrusn/C As Anode Catalysts For Defc, Jing Zhu, Yi Su, Hua Ma, Fang-Yi Cheng, Zhan-Liang Tao, Jing Liang, Jun Chen

Journal of Electrochemistry

In this paper,the preparation,characterization,and ethanol electrocatalytic oxidation of Pt0.5Ru0.5/C and Pt0.5Ru0.15Sn0.35/C electrocatalysts were reported.The electroless-deposition with sensitization-activation pretreatment was applied to prepare Pt0.5Ru0.5/C and Pt0.5Ru0.15Sn0.35/C electrocatalysts. The XRD and TEM analyses showed that the as-prepared catalysts were composed of well-dispersed PtRu or PtRuSn nanoparticles with an average particle size of about 3 nm.The electrochemical measurements demonstrated that the as-prepared Pt0.5Ru0.5/C and Pt0.5Ru0.15Sn0.35/C catalysts exhibited much enhanced peak current density for ethanol electrooxidation as compared to that synthesized without pretreatment.This result revealed that the pretreatment is favorable to the dispersion,size distribution and alloy degree of the nanocatalysts on the carbon support.In …

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Foraminifer And Ostracod Faunas Of The Submarine Hill Harmantaşi Locality (Gulf Of Saros, Northern Aegean Sea) And The Impact Of The Underwater Springs On The Fauna, Engin Meri̇ç, Niyazi Avşar, Atike Nazi̇k, Cemal Tunoğlu, Baki Yokeş, İpek F. Barut, Fulya Yücesoy Eryilmaz, Beril Tuğrul, Muhittin Görmüş, M. Salim Öncel, Hacı Orak, Erol Kam, Feyza Di̇nçer May 2008

Foraminifer And Ostracod Faunas Of The Submarine Hill Harmantaşi Locality (Gulf Of Saros, Northern Aegean Sea) And The Impact Of The Underwater Springs On The Fauna, Engin Meri̇ç, Niyazi Avşar, Atike Nazi̇k, Cemal Tunoğlu, Baki Yokeş, İpek F. Barut, Fulya Yücesoy Eryilmaz, Beril Tuğrul, Muhittin Görmüş, M. Salim Öncel, Hacı Orak, Erol Kam, Feyza Di̇nçer

Bulletin of the Mineral Research and Exploration

No abstract provided.

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Trace Fosil Associations And Palaeoenvironmental Interpretation Of The Late Eocene Units (Sw-Thrace), Huriye Demi̇rcan May 2008

Trace Fosil Associations And Palaeoenvironmental Interpretation Of The Late Eocene Units (Sw-Thrace), Huriye Demi̇rcan

Bulletin of the Mineral Research and Exploration

No abstract provided.

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Presence Of Crassostrea Gryphoides (Schlotheim) From The Lowermiddle Miocene Sequence Of Kahramanmaraş Basin (Se Turkey); Its Taxonomy, Paleoecology And Paleogeography, İzzet Hoşgör May 2008

Presence Of Crassostrea Gryphoides (Schlotheim) From The Lowermiddle Miocene Sequence Of Kahramanmaraş Basin (Se Turkey); Its Taxonomy, Paleoecology And Paleogeography, İzzet Hoşgör

Bulletin of the Mineral Research and Exploration

No abstract provided.

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.Origin Of Magnesite Occurences In Süleymani̇ye, Mi̇halliçik, Eski̇şehi̇r, Türki̇ye, Asuman Yilmaz, Mustafa Kuşcu May 2008

.Origin Of Magnesite Occurences In Süleymani̇ye, Mi̇halliçik, Eski̇şehi̇r, Türki̇ye, Asuman Yilmaz, Mustafa Kuşcu

Bulletin of the Mineral Research and Exploration

No abstract provided.

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Mining Geology Of The Gold Occurrences Related To The Arsenopyrites Of İzmi̇r-Ödemi̇ş Region, Sinan Akiska, Taner Ünlü, İ. Sönmez Sayili May 2008

Mining Geology Of The Gold Occurrences Related To The Arsenopyrites Of İzmi̇r-Ödemi̇ş Region, Sinan Akiska, Taner Ünlü, İ. Sönmez Sayili

Bulletin of the Mineral Research and Exploration

No abstract provided.

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On Measuring The Relative Importance Of Explanatory Variables In A Logistic Regression , D. Roland Thomas, Pengcheng Zhu, Bruno D. Zumbo, Shantanu Dutta May 2008

On Measuring The Relative Importance Of Explanatory Variables In A Logistic Regression , D. Roland Thomas, Pengcheng Zhu, Bruno D. Zumbo, Shantanu Dutta

Journal of Modern Applied Statistical Methods

A search is described for valid methods of assessing the importance of explanatory variables in logistic regression, motivated by earlier work on the relationship between corporate governance variables and the issuance of restricted voting shares (RSF). The methods explored are adaptations of Pratt’s (1987) approach for measuring variable importance in simple linear regression, which is based on a special partition of R2. Pseudo-R2 measures for logistic regression are briefly reviewed, and two measures are selected which can be partitioned in a manner analogous to that used by Pratt. One of these is ultimately selected for the variable …

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Using Connectionist Models To Evaluate Examinees’ Response Patterns To Achievement Tests, Mark J. Gierl, Ying Cui, Steve Hunka May 2008

Using Connectionist Models To Evaluate Examinees’ Response Patterns To Achievement Tests, Mark J. Gierl, Ying Cui, Steve Hunka

Journal of Modern Applied Statistical Methods

The attribute hierarchy method (AHM) applied to assessment engineering is described. It is a psychometric method for classifying examinees’ test item responses into a set of attribute mastery patterns associated with different components in a cognitive model of task performance. Attribute probabilities, computed using a neural network, can be estimated for each examinee thereby providing specific information about the examinee’s attribute-mastery level. The pattern recognition approach described in this study relies on an explicit cognitive model to produce the expected response patterns. The expected response patterns serve as the input to the neural network. The model also yields the cognitive …

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Log-Linear Model To Assess Socioeconomic And Environmental Factors With Childhood Diarrhea Using Hospital Based Surveillance, Krishnan Rajendran, Thandavarayan Ramamurthy, Sujit Kumar Bhattacharya May 2008

Log-Linear Model To Assess Socioeconomic And Environmental Factors With Childhood Diarrhea Using Hospital Based Surveillance, Krishnan Rajendran, Thandavarayan Ramamurthy, Sujit Kumar Bhattacharya

Journal of Modern Applied Statistical Methods

Categorical outcomes with environment factors analyzed by log linear model are frequent in the environmental epidemiological literature. Epidemiological and socio-economical factors were obtained on 1,119 children below the age of 5 from Infectious Diseases Hospital (IDH) at the Kolkata, India. Significant associations of diarrhea were observed in the rural areas with family income, father’s occupation as a daily labor, literacy of parents, non-cemented floor and wall constructed of mud, and type of storage (wide mouthed earthen pot). The results of the study with specific Log linear model confirm environmental factors were important implications for childhood diarrhea in the rural community. …

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On A Test Of Independence Via Quantiles That Is Sensitive To Curvature, Rand R. Wilcox May 2008

On A Test Of Independence Via Quantiles That Is Sensitive To Curvature, Rand R. Wilcox

Journal of Modern Applied Statistical Methods

Let (Yi ,Xi ) , i =1,..., n , be a random sample from some p+1 variate distribution where Xi is a vector having length p. Many methods for testing the hypothesis that Y is independent of X are relatively insensitive to a broad class of departures from independence. Power improvements focus on the median of Y or some other quantile and test the hypothesis that the regression surface is a horizontal plane versus some unknown form. A wild bootstrap method (Stute et al. 1998) can be used based on quantiles, but with small or moderate sample …

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Selection Of Non-Regular Fractional Factorial Designs When Some Two-Factor Interactions Are Important, Weiming Ke, Rui Yao May 2008

Selection Of Non-Regular Fractional Factorial Designs When Some Two-Factor Interactions Are Important, Weiming Ke, Rui Yao

Journal of Modern Applied Statistical Methods

A new method is proposed for selecting the optimal non-regular fractional factorial designs in the situation when some two-factor interactions are potentially important. Searching for the best designs according to this method is discussed and some results for the Plackett-Burman design of 12 runs are presented.

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