In this paper, we wish to present an overview of the research carried out in our laboratories with low-cost transition metal oxides (manganese dioxide, iron oxide and vanadium oxide) as active electrode materials for aqueous electrochemical supercapacitors. More specifically, the paper focuses on the approaches that have been used to increase the capacitance of the metal oxides and the cell voltage of the supercapacitor. It is shown that the cell voltage of an electrochemical supercapacitor can be increased significantly with the use of hybrid systems. The most relevant associations are Fe3O4 or activated carbon as the negative electrode and MnO2 as the positive. The cell voltage of the Fe3O4/MnO2 device is 1.8 V and this value was increased to 2.2 V by using activated carbon instead of Fe3O4. These two systems have shown superior behavior compared to a symmetric MnO2/MnO2 device which only works within a 1 V potential window in aqueous K2SO4. Furthermore, the activated carbon/MnO2 hybrid device exhibits a real power density of 605 W/kg (maximum power density =19.0 kW/kg) with an energy density of 17.3 Wh/kg. These values compete well with those of standard electrochemical double layer capacitors working in organic electrolytes.

http://ma.ecsdl.org/content/MA2005-01/35/1348.full.pdf

Nanostructured Transition Metal Oxides for Aqueous Hybrid Electrochemical Supercapacitors

Solid-state electronics

Research Section Analysis of 200 food items for benzo[a]pyrene and estimation of its intake ίη an epidemiologic study* Ν. Kazerouni a,c,*, R. Sinha a, Che-Han Hsu b,l, Α. Greenberg b,2, Ν. Rothman a "Divi8ion οι CαncCl' Epiden1iology αnd Genetic8, ΝαΙίοnαl Cαncer In8titute, ΝαΙίοnαl Ιn8ιίΙιιΙα ο/' Heαlth, Eχeωtίve ΡΙαΖα South, RIl1 7033, 6120 Execι;tivc Blvd, Rockvillc, MD 20892, USA bDepαrtIl1ent οjΈnvίrοnΙl1entαl SciencC8, Cook c.Όllege, RLifger8 υnίνCI'8ίΙΥ, Nell' Bnln8\vicl(, NJ 08903, USA CDeΡαι'Ιn1ent οι ΡΓeνenιίve Medicine αnd BiOlneuiC8, Unij(JΓmed Scγvice8 υnίνcγ8ίΙγ οjΊlιe ΗeαΙιl1 S(:ienC'e8, 4301 Jone8 BI'i,!ge Roαd, BethC8dα, MD 20814-4799, USA Accepted 1 October 2000 Animal stιιdies have shown that dietary intake of benzo[α]pyrene (BaP), a polycyclic aromatic hydrocarbon (ΡΑΗ), canses increased levels of tumors at several sites, particιιlarly ίη the upper gastrointestinal tract. However, the role of dietary intake of BaP and cancer ίη humans is not clear. We CIeated a BaP database of selected food products that could be lίnl(ed to Food Frequency Qnestionnaires (FFQs) to estimate BaP intake. BaP levels were measnred for each food line-item (composite samples) which consisted of a variety of foods ίη a FFQ. Composite sample parts were derived from the Second National Health and Nutrition Examination Survey (NHANES Π) which represents the most common food items consumed by the general popιιlation. Meat samples were cooked by different techniqnes ίn controlled conditions, and by varions restanrants and fast-food chains. Non-meat products were purchased from the major national supermarket chains. The qnantities of BaP were measnred using a thin-Iayer chromatography (TLC)/spectrofluorometer technique and were highly coaelated with both BaP (radius = 0.99) and sum of carcinogenic ΡΑΗ (1'=0.98) measured by HPLC technique. We lίnl(ed ΟΙΙΓ database to the results from a FFQ and estimated the daily BaP intal<e of varions food items ίη 228 snbjects ίn the Washington, DC metropolitan area. The highest levels of BaP (ιιρ to abont 4 ng BaP/g of cooked meat) were found ίη grilled/barbecued very well done steaks and hamburgers and ίη grilled/barbecued well done chicken with skin. BaP concentrations were lower ίη meats that were grilled/barbecued to medium done and ίη all broiled ΟΓ pan-fried meat samples regardless of doneness level. The BaP levels ίn non-meat items were generally low. However, certain cereals and greens (e.g. I<ale, collard greens) had levels ιιρ to 0.5 ng/g. Ιη our population, the bread/cereal/grain, and grilled/barbecued meat, respectively, contributed 29 and 21 Ρeιτent to the mean daily intal(e of BaP. This database may be helpful ίη initial attempts to assess dietary BaP exposnres ίn stιιdies of cancer etiology. Pnblished by Elsevier Science Ltd. Κcγ\VΟΓds: Po!ycyc!ic aromatic hydrocarbons; Benzo[α]pyrene; Meat; Pork; Chicken; Seafood; Vegetab!es; Fruit; Grains; Fat; Sweets; Pan-fry; Oven-broi1; Gri11; Barbecue; Carcinogenic; Food frequency questionnaire; Cancer AbbI'eviαtion8: ΒαΡ, benzo[α]pyrene; FFQ, Food Frequency Questionnaire; HCA, heterocyc1ic amine(s); ΡΑΗ, p01ycyc1ic aromatic hydrocaΓbοn(s); HHHQ, Hca!th Habits and ΗίstΟΓΥ QιιcstίοnnaίΓC; ng, nanοgΓanι; NHANES ΙΙ, Sccond Nationa! Hca!th and NιιtΓίΙίon Examination Survey; TLC, thin !ayer chromatography; THEES, Tota! Ηηmαη Exposure to Environmenta! Substances. The opinions ΟΓ assertions contained herein are the private ones ο[ the author and are ηοΙ Ιο be constrned as officia! ΟΓ reflecting the views ο[ the United States Department of Defense ΟΓ the Uniforιned Services University of the Health Sciences. * COΓrcsponding aιιthΟΓ. Tcl.: + 1301-594-7296; fax: + 1301-496-1854. E-ιnαil α(/drc8s: kazeroun@exchange.nih.gov (Ν. Kazerouni). \ CLIncnt addΓCSS: DCΡaΓtmcnt ofHospita! and Hca!th CaΓC ΑdnιίnίstΓatίοn, Chnng-Tai Institιιtc ofHca!th Scicnccs and Tcchno!ogy, 11, Po-tzc Lane, Τα1ωn, Taichung, 40605, Taiwan, ROC. 2 Cnrrent address: Department ο[ Chemistry, University ο[ New Hampshire, Dnrham, ΝΗ 03824, USA. 0278-6915/01/$ scc front mattcJ' Pnblishcd by EIscvicJ' Scicncc Ltd. ΡΙΙ: S0278-6915(00)00158-7

/pdf/analysis-of-200-food-items-for-benzo-a-pyrene-andestimation-489ucs4d1d.pdf

Analysis of 200 food items for benzo[a]pyrene andestimation of its intake ίη an epidemiologic study

We have investigated the influences of aluminum and gallium dopants (0 to 2.0 mol%) on zinc oxide (ZnO) thin films regarding crystallization and electrical and optical properties for application in transparent conducting oxide devices. Al- and Ga-doped ZnO thin films were deposited on glass substrates (corning 1737) by sol–gel spin-coating process. As a starting material, AlCl3⋅6H2O, Ga(NO3)2, and Zn(CH3COO)2⋅2H2O were used. A lowest sheet resistance of 3.3 × 103 Ω/□ was obtained for the GZO thin film doped with 1.5 mol% of Ga after post-annealing at 650°C for 60 min in air. All the films showed more than 85% transparency in the visible region. We have studied the structural and microstructural properties as a function of Al and Ga concentrations through X-ray diffraction and scanning electron microscopy analysis. In addition, the optical bandgap and photoluminescence were estimated.

/pdf/comparative-studies-of-al-doped-zno-and-ga-doped-zno-1nn9gue2j7.pdf

Comparative studies of Al-doped ZnO and Ga-doped ZnO transparent conducting oxide thin films

Electrodeposition of Ni-Fe alloys, composites, and nano coatings–A review

Thickness dependence of structural, electrical and optical properties of sprayed ZnO:Cu films

ZnSe thin films have been deposited on high cleaned glass substrate by spray 
pyrolysis technique within the glass substrate temperature range (400 ○C 
to 450 ○C). The structural properties of ZnSe thin films have been 
investigated by (XRD) X-ray diffraction techniques. The X-ray diffraction 
spectra showed that ZnSe thin films are polycrystalline and have a cubic 
(zinc blende) structure. The most preferential orientation is along the 
(111) direction for all spray deposited ZnSe films together with 
orientations in the (220) and (311) planes also being abundant. The film 
thickness was determined by an interferometric method. The lattice 
parameter, grain size, microstrain and dislocation densities were calculated 
and correlated with the substrate temperature (TS). The optical 
properties of ZnSe thin films have been investigated by UV/VIS spectrometer 
and the direct band gap values were found to be in the region of 2.65 eV to 
2.70 eV. The electrical properties of ZnSe thin films have been investigated 
using the Van der Pauw method and the high quality ZnSe thin films were 
observed to develop at 430 ○C with a resistivity of 56,4×105 ohm cm, a conductivity of 1.77×10-7 (Ω cm)-1 and a hall 
mobility of 0.53 cm2/Vsec.

Investigations on structural, optical and electrical parameters of spray deposited ZnSe thin films with different substrate temperature

Zinc sulfide (ZnS) thin films were deposited on a glass substrate by the spray pyrolysis technique. The films were doped with copper using the direct method, consisting in addition of a copper salt (CuCl2) to the spray solution of ZnS. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermoluminescence (TL). XRD as well as SEM techniques have been employed to investigate the structure and surface morphology of as-deposited and doped films. Optical properties, such as transmission and the band gap have been analyzed. A drastic change in the resistivity has been observed due to the incorporation of Cu dopant and the results are discussed in detail. The effect of the spraying time on the electrical and optical properties of the films has been studied.

Metin Bedir

Papers

Thickness dependence of structural, electrical and optical properties of sprayed ZnO:Cu films

Investigations on structural, optical and electrical parameters of spray deposited ZnSe thin films with different substrate temperature

Characterization of copper-doped sprayed ZnS thin films

Effect of sample producing conditions on the thermoluminescence properties of ZnS thin films developed by spray pyrolysis method

The thermoluminescence properties of copper doped ZnS nanophosphor