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Sample records for anrs co3 aquitaine

  1. Incidence and Risk Factors for Severe Bacterial Infections in People Living with HIV. ANRS CO3 Aquitaine Cohort, 2000–2012

    Science.gov (United States)

    Collin, Amandine; Le Marec, Fabien; Vandenhende, Marie-Anne; Lazaro, Estibaliz; Duffau, Pierre; Cazanave, Charles; Gérard, Yann; Dabis, François; Bruyand, Mathias; Bonnet, Fabrice

    2016-01-01

    Severe non-AIDS bacterial infections (SBI) are the leading cause of hospital admissions among people living with HIV (PLHIV) in industrialized countries. We aimed to estimate the incidence of SBI and their risk factors in a large prospective cohort of PLHIV patients over a 13-year period in France. Patients followed up in the ANRS CO3 Aquitaine cohort between 2000 and 2012 were eligible; SBI was defined as a clinical diagnosis associated with hospitalization of ≥48 hours or death. Survival analysis was conducted to identify risk factors for SBI.Total follow-up duration was 39,256 person-years [PY] (31,370 PY on antiretroviral treatment [ART]). The incidence of SBI decreased from 26.7/1000 PY [95% CI: 22.9–30.5] over the period 2000–2002 to 11.9/1000 PY [10.1–13.8] in 2009–2012 (p 50 copies/mL (Hazard Ratio [HR] = 5.1, 95% Confidence Interval: 4.2–6.2), CD4 count <500 cells/mm3 and CD4/CD8 ratio <0.8 (with a dose-response relationship for both markers), history of cancer (HR = 1.4 [1.0–1.9]), AIDS stage (HR = 1.7 [1.3–2.1]) and HCV coinfection (HR = 1.4, [1.1–1.6]). HIV-positive patients with diabetes were more prone to SBI (HR = 1.6 [0.9–2.6]). Incidence of SBI decreased over a 13-year period due to the improvement in the virological and immune status of PLHIV on ART. Risk factors for SBI include low CD4 count and detectable HIV RNA, but also CD4/CD8 ratio, HCV coinfection, history of cancer and diabetes, comorbid conditions that have been frequent among PLHIV in recent years. PMID:27050752

  2. Severe morbidity according to sex in the era of combined antiretroviral therapy: the ANRS CO3 Aquitaine Cohort.

    Directory of Open Access Journals (Sweden)

    Mojgan Hessamfar

    Full Text Available To describe trends and determinants of severe morbidity in HIV-infected women and men.A French prospective cohort of HIV-infected patients of both sexes and all transmission categories.We used hospital admission data from January 2000 to December 2008. A severe morbid event (SME was defined as a clinical event requiring hospitalization for ≥48 h, several events could be reported during hospitalization. Yearly incidence rates of SME were estimated and compared using Generalized Estimating Equations.Among 4,987 patients (27% women, followed for a median of 8.7 years, 1,473 (30% were hospitalized (3,049 hospitalizations for 5,963 SME. The yearly incidence rate of hospitalization decreased in men, from 155 in 2000 to 80/1,000 person-years (PY in 2008 and in women, from 125 to 71/1,000 PY, (p50 years, HIV RNA >10,000 copies, CD4 <500/mm3, AIDS stage, hepatitis C co-infection and cardiovascular risk factors (diabetes, high blood pressure, and tobacco use were associated with SME.HIV-infected individuals in care in France require less and less frequently hospitalization. Women are now presenting with severe hepatic and cardio-vascular events. Disparities in SME between men and women are primarily explained by different exposure patterns to risk factors. Women should be targeted to benefit cardiovascular prevention policies as well as men.

  3. Role of traditional risk factors and antiretroviral drugs in the incidence of chronic kidney disease, ANRS CO3 Aquitaine cohort, France, 2004-2012.

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    Philippe Morlat

    Full Text Available OBJECTIVE: To examine the role of antiretroviral drugs (ART, HIV-related and traditional risk factors on the incidence of chronic kidney disease (CKD in HIV-infected patients. DESIGN: Prospective hospital-based cohort of HIV-infected patients from 2004 to 2012. METHODS: CKD was defined using MDRD equation as an estimated glomerular filtration rate (eGFR less than 60 ml/mn/1.73 m(2 at 2 consecutive measurements ≥3 months apart. Poisson regression models were used to study determinants of CKD either measured at baseline or updated. ART exposure was classified as ever or never. We additionally tested the role of tenofovir (TDF, whether or not prescribed concomitantly with a Protease Inhibitor (PI, taking into account the cumulative exposure to the drug. RESULTS: 4,350 patients (74% men with baseline eGFR>60 ml/mn/1.73 m(2 were followed for a median of 5.8 years. At the end of follow-up, 96% had received ART, one third of them (35% jointly received TDF and a PI. Average incidence rate of CKD was 0.95% person-years of follow-up. Incidence of CKD was higher among women (IRR = 2.2, older patients (>60 y vs 90 and IRR = 7.1 for 70500/mm(3 (IRR = 2.5, and exposure to TDF (IRR = 2.0. Exposure to TDF was even strongly associated with CKD when co-administered with PIs (IRR = 3.1 vs 1.3 when not, p12 months [IRR = 3.0 with joint PIs vs 1.3 without (p<0.001]. A vast majority of those developing CKD (76.6% had a baseline eGFR between 60 and 80 ml/mn/1.73 m(2. CONCLUSION: In patients with eGFR between 60 and 80 mL/min/1.73 m(2, a thorough control of CKD risk factors is warranted. The use of TDF, especially when co-administered with PIs, should be mentioned as a relative contraindication in presence of at least one of these risk factors.

  4. The Aquitaine basin

    Energy Technology Data Exchange (ETDEWEB)

    Biteau, J.-J.; Le Marrec, A.; Le Vot, M.; Masset, J.-M.

    2006-07-01

    The Aquitaine Basin is located in the southwest of France, between the Gironde Arch in the north and the Pyrenean Mountain Chain in the south. It is a triangular-shaped domain, extending over 35000km{sup 2}. From north to south, six main geological provinces can be identified: (1) the Medoc Platform located south of the Gironde Arch; (2) the Parentis sub-basin; (3) the Landes Saddle; (4) the North Aquitaine Platform; (5) the foreland of the Pyrenees (also known as the Adour, Arzacq and Comminges sub-basins); and (6) the Pyrenean fold-and-thrust belt. Only the Parentis sub-basin, the foreland of the Pyrenean Chain and a minor part of the fold-and-thrust belt itself are proven hydrocarbon provinces. The Aquitaine Basin, in turn, is subdivided into four sub-basins - the Parentis, Adour-Arzacq, Tarbes and Comminges areas. The lozenge shape of these depocentres is related to the Hercynian tectonic framework of the Palaeozoic basement, reactivated during Early Cretaceous rifting. This rift phase aborted at the end of the Albian (prior to the development of an oceanic crust) in response to the beginning of the subduction of the Iberian plate under the European plate. During the Upper Cretaceous, continued subduction led to the creation of northwards-migrating flexural basins. In the Eocene, a paroxysmal phase of compression was responsible for the uplift of the Pyrenean Mountain Chain and for the thin-skinned deformation of the foreland basin. The resulting structuration is limited to the south by the internal core of the chain and to the north by the leading edge of the fold-and-thrust belt, where the Lacq and Meillon gas fields are located. Four main petroleum provinces have been exploited since the Second World War: (1) the oil-prone Parentis sub-basin and (2) salt ridges surrounding the Arzacq and Tarbes sub-basins; and (3) the gas-prone southern Arzacq sub-basin (including the external Pyrenean fold-and-thrust belt and the proximal foreland sub-basin) and (4

  5. The renewable energies panorama in Aquitaine; Panorama des energies renouvelables en Aquitaine

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    The Information network on the Economic Development in Aquitaine (IDEA) aims to collect and spread the environmental information concerning the Aquitaine, in order to implement an observatory of the regional environment and of the sustainable development. This panorama takes stock on the renewable energies development in Aquitaine: photovoltaic, geothermal energy, thermal solar, hydroelectricity and cogeneration. (A.L.B.)

  6. Wastes in Aquitaine. A regional guide; Les dechets en Aquitaine. Guide regional

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-04-01

    In the framework of French environmental policy and municipal and industrial waste disposal programs, a guide is presented for the Aquitaine region, which gives a comprehensive information on waste disposal effects and waste processing. Waste types and associated regulations are presented, with emphasis on volumes and data for Aquitaine region, followed by information on the various environmental labels and waste collection procedures, processing and ultimate disposal systems, financial incentives and taxes, waste exchange systems... The various types of municipal, industrial, agricultural and food industry wastes are reviewed with information on their characteristics, volumes, legislation, collection, processing and upgrading, and disposal

  7. Liner «L’Aquitaine» (1899-1906

    Directory of Open Access Journals (Sweden)

    Jean Guiglini

    2016-09-01

    Full Text Available The paper gives a brief biography of the French liner «L'Aquitaine», before the Spanish auxiliary cruiser «Patriota». The article is illustrated with photographs from the collection of the author.

  8. [Intoxications specific to the Aquitaine region].

    Science.gov (United States)

    Bédry, R; Gromb, S

    2009-07-01

    Some intoxications are more specifically linked to the Aquitaine region than to other regions of France, due to environmental circumstances (fauna, flora, climate) or traditional activities (gastronomy). Three types of intoxications are particular in this area. Pine processionary caterpillar envenomations (Thaumetopoea pityocampa), a Southern Europe pinewood parasite, are frequently encountered in the Landes' forest. They are responsible of ocular and/or skin lesions with urticaria or contact dermatitis, seldom associated with immediate IgE hypersensitivity. According to the south Atlantic coastal region geology and the marine streams, venomous marine animals are mainly located in Charente-Maritime for jellyfish, in Gironde and in Landes for weeverfish and in Atlantic Pyrenees for sea anemone. Usually not dangerous, first-aid workers treat most cases of these envenomations. Some endemic mushrooms (Tricholoma auratum) which grow on the dunes of the Atlantic coastal region, are usually considered as very good comestibles, but were recently responsible for serious intoxications: T.auratum was responsible of several cases of rhabdomyolysis, without neurological involvement, nor renal or hepatic lesion. Three deaths were notified. Animal studies confirmed the responsibility of the mushrooms.

  9. Homotopy Characterization of ANR Function Spaces

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    Jaka Smrekar

    2013-01-01

    Full Text Available Let Y be an absolute neighbourhood retract (ANR for the class of metric spaces and let X be a topological space. Let YX denote the space of continuous maps from X to Y equipped with the compact open topology. We show that if X is a compactly generated Tychonoff space and Y is not discrete, then YX is an ANR for metric spaces if and only if X is hemicompact and YX has the homotopy type of a CW complex.

  10. Terroir and Cultural patrimony: reflections on regional cuisines in Aquitaine

    Directory of Open Access Journals (Sweden)

    Isabelle Techoueyres

    2001-10-01

    Full Text Available Today the South West of France is widely renown for its cuisine and gastronomy. This presentation aims at exploring the different ingredients which contribute to the making of the concept of Regional Cuisine. It is based on field work undertaken in Aquitaine: it involved visits to families including 2 and even 3 generations in different areas, with interviews of individuals, observation, discussions. And also interviews with producers of food-products a well as persons in charge of their prom...

  11. Faune-Aquitaine : portail collaboratif sur la biodiversité régionale

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    Jérémiah Liger

    2014-06-01

    Full Text Available Le site www.faune-aquitaine.org fait partie du projet national Visionature (www.ornitho.fr. Ce site est géré par la Ligue de Protection des Oiseaux en Aquitaine (LPO-Aquitaine, une association à but non-lucratif dédiée à la protection de la biodiversité et particulièrement des oiseaux dans la région Aquitaine. Elle est le représentant régional de la LPO nationale et de BirdLife International. Faune-Aquitaine est un site de collecte et de diffusion des observations d’oiseaux, de mammifères (...

  12. Technical meeting of OREAQ (Regional Observatory of Energy in Aquitaine): energy and greenhouse gases in Aquitaine, the system of the green certificates and the green electricity market; Rencontre technique de l'OREAQ (Observatoire Regional de l'Energie en Aquitaine): energie et gaz a effet de serre en Aquitaine, le systeme des certificats verts et le marche de l'electricite verte

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    The Information network on the Economic Development in Aquitaine (IDEA) aims to collect and spread the environmental information concerning the Aquitaine, in order to implement an observatory of the regional environment and of the sustainable development. This meeting is devoted to the greenhouse effect in Aquitaine. It discusses the carbon dioxide emissions bond to the energy, the green certificates and the green electricity market in France. (A.L.B.)

  13. 76 FR 56191 - Notice of Application; ANR Pipeline Company

    Science.gov (United States)

    2011-09-12

    ..., operate, and maintain its Marshfield Reduction Project (MRP), comprised of a new 6,300 horsepower... County, Wisconsin, north of Stevens Point, Wisconsin, the MRP will eliminate the need for certain... Wisconsin. ANR states that the MRP will increase the reliability and flexibility of service for...

  14. Prof. Zhu Zuoyan Met with Director General of ANR

    Institute of Scientific and Technical Information of China (English)

    Fan Yingjie; Lu Rongkai

    2007-01-01

    @@ On Feb. 2, 2007, Prof. Zhu Zuoyan, Vice President of NSFC met with Ms. Jacqueline Lecourtier, Director General of the French National Research Agency (Agence Nationale de la Recherche, ANR) and Mr.Bernard Belloc, the Science and Technology Counselor of the French Embassy in China.

  15. Normal Systems over ANR's, Rigid Embeddings and Nonseparable Absorbing Sets

    Institute of Scientific and Technical Information of China (English)

    Piotr NIEMIEC

    2012-01-01

    Most of results of Bestvina and Mogilski [Characterizing certain incomplete infinite-dimensional absolute retracts.Michigan Math.J.,33,291-313 (1986)] on strong Z-sets in ANR's and absorbing sets is generalized to nonseparable case.It is shown that if an ANR X is locally homotopy dense embeddable in infinite-dimensional Hilbert manifolds and w(U) = w(X) (where “w”is the topological weight) for each open nonempty subset U of X,then X itself is homotopy dense embeddable in a Hilbert manifold.It is also demonstrated that whenever X is an AR,its weak product W(X,*)={( Xn)∞n=1∈Xω∶xn=* for almost all n} is homeomorphic to a pre-Hilbert space E with E ≌∑E.An intrinsic characterization of manifolds modelled on such pre-Hilbert spaces is given.

  16. The effects of mutation of the anr gene on the aerobic respiratory chain of Pseudomonas aeruginosa.

    Science.gov (United States)

    Ray, A; Williams, H D

    1997-11-15

    The anr gene of Pseudomonas aeruginosa encodes a transcriptional regulator of anaerobic gene expression, homologous to the Fnr protein of Escherichia coli. We report here that Anr has a role in regulating the activity of the aerobic respiratory chain of P. aeruginosa. Strains with internal deletions in their anr gene had lowered levels of membrane bound cytochromes whilst the activity of the cytochrome c oxidase, cytochrome co (likely to be a cytochrome cbb3-type oxidase), and the cyanide-insensitive respiratory pathway was markedly higher than in the wild-type strains. These data, and the finding that provision of multiple copies of the anr gene led to severe repression of these respiratory activities, suggest that Anr is a repressor of aerobic respiratory pathways and possibly the terminal oxidases themselves. In contrast, Anr activated cytochrome c peroxidase, a respiratory chain linked enzyme induced under low oxygen conditions.

  17. 78 FR 59927 - ANR Pipeline Company; Notice of Request Under Blanket Authorization

    Science.gov (United States)

    2013-09-30

    ..., Jefferson, and Des Moines County, Iowa (Iowa Fertilizer Project). ANR states that the Iowa Fertilizer Project will deliver 81,000 dekatherms per day to a new nitrogen fertilizer manufacturing plant. ANR estimates the cost of the Iowa Fertilizer Project to be approximately $15 million, all as more fully...

  18. Natural Gas Seepage Along the Edge of the Aquitaine Shelf (France): Origin and Flux Measurements

    Science.gov (United States)

    Ruffine, L.; Donval, J. P.; Battani, A.; Bignon, L.; Croguennec, C.; Caprais, J. C.; Birot, D.; Bayon, G.; Lantéri, N.; Levaché, D.; Dupré, S.

    2014-12-01

    A newly discovered and highly active seepage area has been acoustically mapped at the western edge of the Aquitaine Shelf in the Bay of Biscay [Dupré et al., 2014]. Three selected seeping sites have been investigated with a Remotely Operated Vehicle. All sites were characterized by vigorous gas emissions, and the occurrence of massive carbonate crusts and bacterial mats at the seafloor. Nine seeps have been sampled with the PEGAZ sampler. The latter allowed gas-bubble sampling and preservation at in situpressure, together with gas-flux measurement through its graduated transparent cone. The C2+ fraction of the gas samples accounts for less than 0.06 %-mol of the total composition. Both the abundance of methane and dD and d13C isotopic analyses of the hydrocarbons indicate a biogenic source generated by microbial reduction of carbon dioxide [Whiticar et al., 1986]. The analyses of the associated noble gases also provide further support for a shallow-depth generation. While sharing the same origin, the collected samples are different in other respects, such as the measured d13C values for carbon dioxide and the hydrocarbons. This is the case in particular for methane, with displays values in between -66.1 and -72.7 ‰. We hypothesized that such variations are the result of multiple gas-transport processes along with the occurrence of hydrocarbon oxidation at different rates within the sedimentary column. The measured gas fluxes are extremely heterogeneous from one seep to another, ranging from 18 to 193 m3.yr-1. These values will be discussed in detail by comparing them with values obtained from different measurement techniques at other gas-seeping sites. The GAZCOGNE study is co-funded by TOTAL and IFREMER as part of the PAMELA (Passive Margin Exploration Laboratories) scientific project. References:Dupré, S., L. Berger, N. Le Bouffant, C. Scalabrin, and J. F. Bourillet (2014), Fluid emissions at the Aquitaine Shelf (Bay of Biscay, France): a biogenic origin or

  19. CaCO3 and SrCO3 bioprecipitation by fungi isolated from calcareous soil.

    Science.gov (United States)

    Li, Qianwei; Csetenyi, Laszlo; Paton, Graeme Iain; Gadd, Geoffrey Michael

    2015-08-01

    The urease-positive fungi Pestalotiopsis sp. and Myrothecium gramineum, isolated from calcareous soil, were examined for their properties of CaCO3 and SrCO3 biomineralization. After incubation in media amended with urea and CaCl2 and/or SrCl2 , calcite (CaCO3 ), strontianite (SrCO3 ), vaterite in different forms [CaCO3 , (Cax Sr1-x )CO3 ] and olekminskite [Sr(Sr,Ca)(CO3 )2 ] were precipitated, and fungal 'footprints' were observed on mineral surfaces. The amorphous precipitate mediated by Pestalotiopsis sp. grown with urea and equivalent concentrations of CaCl2 and SrCl2 was identified as hydrated Ca and Sr carbonates by Fourier transform infrared spectroscopy. Liquid media experiments showed M. gramineum possessed the highest Sr(2+) removal ability, and ∼ 49% of supplied Sr(2+) was removed from solution when grown in media amended with urea and 50 mM SrCl2 . Furthermore, this organism could also precipitate 56% of the available Ca(2+) and 28% of the Sr(2+) in the form of CaCO3 , SrCO3 and (Cax Sr1-x )CO3 when incubated in urea-amended media and equivalent CaCl2 and SrCl2 concentrations. This is the first report of biomineralization of olekminskite and coprecipitation of Sr into vaterite mediated by fungi. These findings suggest that urease-positive fungi could play an important role in the environmental fate, bioremediation or biorecovery of Sr or other metals and radionuclides that form insoluble carbonates.

  20. Paramètres statistiques de la houle au large de la côte sud-aquitaine

    Science.gov (United States)

    Abadie, Stéphane; Butel, Rémi; Dupuis, Hélène; Brière, Christophe

    2005-06-01

    Statistical parameters of waves on the south Aquitaine coast have been determined by comparison of two datasets: in situ local measurements on a short duration and numerical simulation outputs from the WAVEWATCH III model over a period of 6 years and 9 months. Data and simulation results are well correlated in the case of the significant wave height, whereas in the case of the peak periods (T) and directions (D), this correlation is lower. This is due respectively to the intrinsic unstable nature of T and the narrow distribution of D. An adjustment of simulation data on measurement is then used to give an evaluation of the wave statistics for the southern fraction of the French Atlantic coast. Eventually, the relationships between the three statistical variables (H,T,D) are analysed in order to determine representative sea states. The classification obtained shows the predominance of swell regimes, distributed on a very narrow angular sector over wind sea regimes. To cite this article: S. Abadie et al., C. R. Geoscience 337 (2005).

  1. Review and recommended thermodynamic properties of FeCO3

    DEFF Research Database (Denmark)

    Fosbøl, Philip Loldrup; Thomsen, Kaj; Stenby, Erling Halfdan

    2010-01-01

    An extensive review of entropy, enthalpy of formation and Gibbs energy of formation, heat capacity, aqueous solubility and solubility constant of FeCO3 is given. A consistent set of thermodynamic properties for FeCO3 and relevant aqeous species is selected and recommended for use. Speciation...... schemes for aqeous FeCO3 are reviewed and evaluated. Issues related to supersaturation of FeCO3 are discussed. Works on the thermal decomposition of FeCO3 are presented and an overview of measured solubility and synthesis of FeCO3 is given....

  2. L'origine des karsts sur la bordure Nord-Est du Bassin Aquitain : une histoire polyphasée et complexe.

    OpenAIRE

    Husson, Eglantine; Camus, H.; Lerouge, Catherine; Couëffé, Renaud; Cabaret, Olivier; Pedron, Nicolas

    2016-01-01

    International audience; Le Bassin sédimentaire aquitain correspond à une vaste dépression au sud-ouest de la France. Largement ouvert vers l'ouest et l'Océan atlantique, il est ceinturé par des reliefs que constituent le Massif Armoricain au nord, par le Massif Central et la Montagne Noire à l'est, et par la chaîne des Pyrénées au sud. La disposition des formations sédimentaires traduit le comblement du bassin sur le socle continental. Les affleurements des terrains jurassiques et crétacés en...

  3. Instabilities and deformation in the sedimentary cover on the upper slope of the southern Aquitaine continental margin, north of the Capbreton canyon (Bay of Biscay)

    OpenAIRE

    Gonthier, E; Cirac, P.; Faugeres, J; Gaudin, Mathieu; Cremer, M; Bourillet, Jean-francois

    2006-01-01

    Acoustic and core data have recently been collected on the shelf break and the upper part of the slope of the south Aquitaine continental margin. They reveal the major role played by mass-flow gravity processes in deposit erosion and redistribution, modelling of the sea-bed, and transfer of sediment toward the deep-sea. The study region is bounded in the south by the Capbreton canyon. The northern area, which shows a smooth morphology, is characterised by small-scale deformations due to sedim...

  4. Comparison of Aquitaine and Rioja Red Wines: Characterization of Their Phenolic Composition and Evolution from 2000 to 2013

    Directory of Open Access Journals (Sweden)

    Cindy Quaglieri

    2017-01-01

    Full Text Available Wine chemical analysis was carried out on 194 commercial blended red wines produced by two major wine-growing areas—the Aquitaine (France and Rioja (Spain regions—in order to compare the wines of both regions. Anthocyanins and derived pigments, tannins and derivatives were identified and quantified by HPLC-DAD-ESI-MS/MS (high pressure liquid chromatography coupled to diode array detector and mass spectrometry using the electrospray ionization interface. Mean degree of polymerization (mDP was determined. The influence of the wine-growing region and the predominance of the properties of some grape varieties used are confirmed by the significant differences observed between both regions. Rioja and Bordeaux “generic” (Bordeaux and Bordeaux-Supérieur appellations red wines showed the highest anthocyanic content and the highest mDP, as these wines are in a majority made from Merlot (Bordeaux “generic” and Tempranillo (Rioja. On the contrary, Bordeaux “specific” regions (Blayais, Médoc, Graves, and Libournais showed the red wines with the highest total phenolic content and tannin concentration, as the predominant grape variety used is Cabernet Sauvignon. A principal component analysis (PCA and a hierarchical ascendant classification (HAC suggesting patterns between the chemical parameters and the distribution of the red wines in three groups were proposed. The comparison of the two wine-growing areas also reveals some similarities between the various grape varieties used. A general effect of a progressive decrease in anthocyanins, anthocyanin-derived pigment and tannins is observed for older wines.

  5. Dietary behaviors as associated factors for overweight and obesity in a sample of adolescents from Aquitaine, France.

    Science.gov (United States)

    Carriere, Caroline; Langevin, Coralie; Lamireau, Thierry; Maurice, Sylvie; Thibault, Hélène

    2013-03-01

    This study aimed to identify dietary behaviors that might be considered as associated factors for overweight or obesity among French adolescents. Forty-nine of the 536 middle and high schools in Aquitaine (southwest of France) were invited to take part in the study. For each school, participating adolescents were selected using stratification by grade. A self-report questionnaire, including information about sex, age, dietary behaviors, physical and sedentary activities, and parental socioeconomic status (SES), was filled in by adolescents during class. Overweight and obesity were defined according to the age- and sex-specific body mass index cutoff points of the International Obesity Task Force. Multivariate analysis (logistic regression) was used to identify independent dietary factors associated with overweight including obesity and obesity alone (adjustment on sex, age, parental SES, and weight status and adolescents' sedentary activity). In addition to parental SES and weight status and adolescents' sedentary activity, some dietary behaviors are also independently and significantly associated with a higher prevalence of overweight including obesity: absence (OR 1.43, 0.91-2.23) or rare (OR 1.57, 1.23-2.01) breakfast intake (p < 0.01) and absence (OR 5.03, 3.19-7.92) or rare (OR 1.90, 1.46-2.47) light afternoon meal intake (p < 0.001). All variables were also significantly and independently associated with obesity alone. This study shows that socioeconomic factors and individual behaviors are associated with overweight or obesity. These results confirm the importance to carry out multifaceted educational actions among adolescents, by promoting physical activity and healthy food choices in order to prevent overweight and promote healthy lifestyle behaviors.

  6. Rencontre ANRS des sites Asie du Sud-Est (Cambodge et Vietnam)

    OpenAIRE

    Hancart Petitet, Pascale

    2010-01-01

    Ces trois journées scientifiques à Hô Chi Minh Ville rassemblaient environ 150 personnes dont de nombreuses personnalités de la riposte au sida autour de Françoise Barré Sinoussi, prix Nobel de Médecine 2008 et Lien Truong Xuan, coordinatrice du ANRS Vietnam, amies et porteuses de projets communs depuis 25 ans. La complicité de ces deux femmes, célébrée à plusieurs reprises, semblait vouloir porter un message fort en cette période de démantèlement institutionnel de la recherche : le monde des...

  7. Switch to Rilpivirine/Emtricitabine/Tenofovir Single-Tablet Regimen of Human Immunodeficiency Virus-1 RNA-Suppressed Patients, Agence Nationale de Recherches sur le SIDA et les Hépatites Virales CO3 Aquitaine Cohort, 2012-2014.

    Science.gov (United States)

    Cazanave, Charles; Reigadas, Sandrine; Mazubert, Cyril; Bellecave, Pantxika; Hessamfar, Mojgan; Le Marec, Fabien; Lazaro, Estibaliz; Peytavin, Gilles; Bruyand, Mathias; Fleury, Hervé; Dabis, François; Neau, Didier

    2015-01-01

    Background.  The purpose of this study was to assess the efficacy and tolerability of combined antiretroviral therapy (cART) in human immunodeficiency virus (HIV)-1 virologically suppressed patients who switched to rilpivirine (RPV)/tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC) as a single-tablet regimen (STR). Methods.  A retrospective multicenter cohort study was performed between September 2012 and February 2014 in Bordeaux University Hospital-affiliated clinics. Patients with a plasma HIV viral load (VL) lower than 50 copies/mL and switching to STR were evaluated at baseline, 3, 6, 9, and 12 months from switch time (M3, M6, M9, M12) for VL and other biological parameters. Change from baseline in CD4 cell counts was evaluated at M6 and M12. Virological failure (VF) was defined as 2 consecutive VL >50 copies/mL. Results.  Three hundred four patients were included in the analysis. Single-tablet regimen switch was proposed to 116 patients with adverse events, mostly efavirenz (EFV)-based (n = 59), and to 224 patients for cART simplification. Thirty of 196 patients with available genotype resistance test results displayed virus with ≥1 drug resistance mutation on reverse-transcriptase gene. After 12 months of follow-up, 93.4% (95.5% confidence interval, 89.9-96.2) of patients remained virologically suppressed. There was no significant change in CD4 cell count. During the study period, 5 patients experienced VF, one of them harboring RPV resistance mutation. Clinical cART tolerability improved in 79 patients overall (29.9%) at M6, especially neurological symptoms related to EFV. Fasting serum lipid profiles improved, but a significant estimated glomerular function rate decrease (-11 mL/min/1.73 m(2); P < 10(-4)) was observed. Conclusions.  Overall, virologic suppression was maintained in patients after switching to RPV/TDF/ FTC. This STR strategy was associated with improved tolerability.

  8. Double magnetic resonance in MnCO3

    Directory of Open Access Journals (Sweden)

    Yu.M. Bunkov, A.V. Klochkov, T.R. Safin, K.R. Safiullin, M.S. Tagirov

    2015-12-01

    Full Text Available Results of experiments on MnCO3 investigations by double magnetic resonance are presented. Additional mode of oscillation has been observed in a created Bose-Einstein condensation of magnons state in MnCO3. The properties of observed signals are similar to Goldstone modes.

  9. Requirement of PSD-95 for dopamine D1 receptor modulating glutamate NR1a/NR2B receptor function

    Institute of Scientific and Technical Information of China (English)

    Wei-hua GU; Shen YANG; Wei-xing SHI; Guo-zhang JIN; Xue-chu ZHEN

    2007-01-01

    Aim: To elucidate the role of scaffold protein postsynaptic density (PSD)-95 in the dopamine D1 receptor (D1R)-modulated NR 1a/NR2B receptor response.Methods: The human embryonic kidney 293 cells expressing D1R (tagged with the enhanced yellow fluorescent protein) and NR1a/NR2B with or without co-expres-sion of PSD-95 were used in the experiments. The Ca2+ influx measured by imaging technique was employed to monitor N-methyl-D-aspartic acid receptors (NMDAR) function.Results: The application of dopamine (DA, 100 μmol/L) did not alter glutamate/glycine (Glu/Gly)-induced NMDAR-mediated Ca2+ influx in cells only expressing the D1R/NR1a/NR2B receptor. However, DA increased Glu/Gly-induced Ca2+ influx in a concentration-dependent manner while the cells were co-expressed with PSD-95. D1.R-stimulated Ca2+ influx was inhibited by a selective DIR antagonist SCH23390. Moreover, pre-incubation with either the protein kinase A (PKA) inhibitor H89, or the protein kinase C (PKC) inhibitor chelerythrine attenuated D1R-enhanced Ca2+ influx induced by the N-methyl-D-aspartie acid (NMDA) agonist. The results clearly indicate that D1R-modulated NR1a/NR2B receptor function depends on PSD-95 and is subjected to the regulation of PKA and PKC.Conclusion: The present study provides the fast evidence that PSD-95 is essential in D iR-regulated NR1a/NR2B receptor function.

  10. Kinetics and Mechanism of the Hydrogenation of CpCr(CO)3•/[CpCr(CO)3]2 Equilibrium to CpCr(CO)3H

    Energy Technology Data Exchange (ETDEWEB)

    Norton, Jack R.; Spataru, Tudor; Camaioni, Donald M.; Lee, Suh-Jane; Li, Gang; Choi, Jongwook; Franz, James A.

    2014-05-26

    The kinetics of the hydrogenation of 2 CpCr(CO)3•/[CpCr(CO)3]2 to CpCr(CO)3H has been investigated. The reaction is second-order in Cr and first-order in H2, with a rate constant of 45 M 2s 1 at 25 °C in benzene. DFT calculations rule out an H2 complex as an intermediate, and suggest (a) end-on approach of H2 to one Cr of [CpCr(CO)3]2 as the Cr-Cr bond undergoes heterolytic cleavage, (b) heterolytic cleavage of the coordinated H2 between O and Cr, and (c) isomerization of the resulting O-protonated CpCr(CO)2(COH) to CpCr(CO)3H. The work at Pacific Northwest National Laboratory (PNNL) was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences; Battelle operates PNNL for DOE.

  11. [Disseminated Mycobacterium avium complex infections in AIDS. Apropos of 100 cases. Groupe d'Epidémiologie clinique du SIDA en Aquitaine].

    Science.gov (United States)

    Lasseur, C; Maugein, J; Pellegrin, J L; Dupon, M; Ragnaud, J M; Morlat, P; Pellegrin, I; Constans, J; Monlun, E; Chene, G

    1995-01-01

    The improvement of survival of AIDS patients allowed the emergence of disseminated Mycobacterium avium Complex infections (D.MAC). Here we report the experience of the group of "Epidémiologie clinique du sida en Aquitaine (GECSA)" about 100 patients. There were no differences according to sex, age and route of acquisition of HIV. Clinical and biological characteristics of the infections were not specific. The mean TCD4+ lymphocytes count was 18/mm3. The diagnostic was generally established by systematic blood culture on Septi-Chek in patients with TCD4+ lymphocytes count below 75/mm3. The recommendations on therapy for D.MAC are to use regimen containing azithromycin or clarithromycin, ethambutol and one of the following drugs, rifabutin, clofazimine, amikacin, or ciprofloxacin. Rifabutin is recommended for prophylaxis in patients with lymphocytes TCD4+ count below 100/mm3.

  12. Microstructural studies of K 2CO 3 and Rb 2CO 3 doped YBCO HTSC

    Science.gov (United States)

    Koblischka-Veneva, A.; Koblischka, M. R.

    2003-10-01

    The influence of Me 2CO 3 (Me=K or Rb) additions on the microstructural morphology of YBa 2Cu 3O x (YBCO) HTSC with nominal composition Y (1-0.2 x) Ba (2-0.2 x) M xCu 3O y ( x=0-2.0) were investigated by means of orientation imaging microscopy which provides a method for measuring a large number of individual grain orientations and relating them directly to the microstructural features by means of evaluating electron backscatter Kikuchi patterns in scanning electron microscopy. We investigated the influence of the alkali additions on the grain orientation distributions of YBCO. The samples are characterized by grain orientation maps, and pole and inverse pole figures. Finally, the grain orientation distribution functions are obtained from the measured data. Within a certain range of doping (up to 5 wt.% in the initial batch), the grain sizes are found to increase as compared to pure YBCO, accompanied by an improvement of the superconducting properties ( Tc). It is shown that the additions of alkali carbonates do not introduce any preferred grain orientations in YBCO HTSC in the entire doping range.

  13. Base documentaire sur les artisanats gallo-romains en Lyonnaise et dans les cités du nord et de l’est de l’Aquitaine : Corpus de données. Présentation Documentary base on the Gallo-Roman craft industries in the Lyonnaise region and the cities of North and East Aquitaine: Data base – presentation

    Directory of Open Access Journals (Sweden)

    Alain Ferdière

    2009-05-01

    Full Text Available Un important corpus de tout type d’artisanat pour la période romaine a été constitué et est ici accessible en lien : il concerne l’ensemble de la province romaine de Lyonnaise (du Finistère au Lyonnais, ainsi que les cités du nord et de l’est de la grande Aquitaine, des Pictons à l’ouest au Gabales au sud-est. Ce corpus examine, par type d’artisanat, essentiellement les contextes (types de sites, chronologie, et non les aspects techniques ou typologiques concernant ces artisanats.An important body of all types of craft industries has been built up for the Roman period and is accessible here in context: it concerns the whole of the Lyonnaise Roman province (from Finistère to Lyonnais as well as the cities of the north and of greater Aquitaine, from the Pictons to the west to the Gabales to the south-east. This body essentially examines for each type of craft industry the contexts (type of site, chronology and not the technical aspects or typologies concerning the craft industries.

  14. Magnetic behavior of biosynthesized Co3O4 nanoparticles

    Science.gov (United States)

    Diallo, A.; Doyle, T. B.; Mothudi, B. M.; Manikandan, E.; Rajendran, V.; Maaza, M.

    2017-02-01

    This contribution reports for the 1st time on the magnetic behavior of CO3O4 nanoparticles synthesized by a "green" process using an Aspalathus linearis' leaves natural extract. More accurately magnetic behavior of CO3O4 nanoparticles successfully biosynthesized was investigated using vibrating sample magnetometer. The magnetization behavior for the samples manifests a combination of size dependent antiferromagnetic and paramagnetic behaviors, respectively, for the core and shell of the nanoparticles.

  15. Methadone induction in primary care (ANRS-Methaville: a phase III randomized intervention trial

    Directory of Open Access Journals (Sweden)

    Roux Perrine

    2012-06-01

    Full Text Available Abstract Background In France, the rapid scale-up of buprenorphine, an opioid maintenance treatment (OMT, in primary care for drug users has led to an impressive reduction in HIV prevalence among injecting drug users (IDU but has had no major effect on Hepatitis C incidence. To date, patients willing to start methadone can only do so in a methadone clinic (a medical centre for drug and alcohol dependence (CSAPA or a hospital setting and are referred to primary care physicians after dose stabilization. This study aims to assess the effectiveness of methadone in patients who initiated treatment in primary care compared with those who initiated it in a CSAPA, by measuring abstinence from street opioid use after one year of treatment. Methods/Design The ANRS-Methaville study is a randomized multicenter non-inferiority control trial comparing methadone induction (lasting approximately 2 weeks in primary care and in CSAPA. The model of care chosen for methadone induction in primary care was based on study-specific pre-training of all physicians, exclusion criteria and daily supervision of methadone during the initiation phase. Between January 2009 and January 2011, 10 sites each having one CSAPA and several primary care physicians, were identified to recruit patients to be randomized into two groups, one starting methadone in primary care (n = 147, the other in CSAPA (n = 48. The primary outcome of the study is the proportion of participants abstinent from street opioids after 1 year of treatment i.e. non-inferiority of primary care model in terms of the proportion of patients not using street opioids compared with the proportion observed in those starting methadone in a CSAPA. Discussion The ANRS-Methaville study is the first in France to use an interventional trial to improve access to OMT for drug users. Once the non-inferiority results become available, the Ministry of Health and agency for the safety of health products may change the the

  16. Elaboration d'un outil de gestion prévisionnelle de la côte Aquitaine - PHASE 1 - Bilan des connaissances sur l'évolution des connaissances sur l'évolution du trait de cote

    OpenAIRE

    Manaud, Francois

    1998-01-01

    L'élaboration d'un outil d'aide à la gestion de la côte d'Aquitaine nécessite dans un premier temps de retracer l'historique des transformations qui ont façonné le tracé de la côte entre la Pointe de Grave et la Pointe St Martin (Biarritz).

  17. Rice-like hollow nano-CaCO3 synthesis

    Science.gov (United States)

    Ulkeryildiz, Eda; Kilic, Sevgi; Ozdemir, Ekrem

    2016-09-01

    We have shown that Ca(OH)2 solution is a natural stabilizer for CaCO3 particles. We designed a CO2 bubbling crystallization reactor to produce nano-CaCO3 particles in homogenous size distribution without aggregation. In the experimental set-up, the crystallization region was separated from the stabilization region. The produced nanoparticles were removed from the crystallization region into the stabilization region before aggregation or crystal growth. It was shown that rice-like hollow nano-CaCO3 particles in about 250 nm in size were produced with almost monodispersed size distribution. The particles started to dissolve through their edges as CO2 bubbles were injected, which opened-up the pores inside the particles. At the late stages of crystallization, the open pores were closed as a result of dissolution-recrystallization of the newly synthesized CaCO3 particles. These particles were stable in Ca(OH)2 solution and no aggregation was detected. The present methodology can be used in drug encapsulation into inorganic CaCO3 particles for cancer treatment with some modifications.

  18. On dimensions modulo a compact metric ANR and modulo a simplicial complex

    CERN Document Server

    Krzempek, Jerzy

    2012-01-01

    V. V. Fedorchuk has recently introduced dimension functions K-dim \\leq K-Ind and L-dim \\leq L-Ind, where K is a simplicial complex and L is a compact metric ANR. For each complex K with a non-contractible join |K| * |K| (we write |K| for the geometric realisation of K), he has constructed first countable, separable compact spaces with K-dim < K-Ind. In a recent paper we have combined an old construction by P. Vop\\v{e}nka with a new construction by V. A. Chatyrko, and have assigned a certain compact space Z (X, Y) to any pair of non-empty compact spaces X, Y. In this paper we investigate the behaviour of the four dimensions under the operation Z (X, Y). This enables us to construct more examples of compact Fr\\'echet spaces which have prescribed values K-dim < K-Ind, L-dim < L-Ind, or K-Ind < |K|-Ind, and (connected) components of which are metrisable.

  19. Mixing Corrosion of CaCO3 in Natural Waters

    Directory of Open Access Journals (Sweden)

    Qian Hui

    2011-01-01

    Full Text Available The methods of aqueous speciation calculation, pH calculation and the solubility (precipitability calculation of CaCO3 were used to study the mixing corrosion of CaCO3 in natural waters. Mixing processes were done between two unsaturated (with CaCO3 solutions, two oversaturated solutions and between an unsaturated solution and an oversaturated solution, respectively. Results show that the mixing corrosion can be divided into two different levels: mixing corrosion in strict sense and mixing corrosion in broad sense. When mixing corrosion occurs, the HCO3- concentration in one end member solution is usually higher than that in the other solution, and the Ca2+ concentration in the former solution is also usually higher than that in the latter one.

  20. VERTEX: Manganese transport with CaCO 3

    Science.gov (United States)

    Martin, John H.; Knauer, George A.

    1983-04-01

    Manganese transport was studied off central California in August and September 1981 as part of the VERTEX (Vertica l Transport and Exchange) research program. Refractory, leachable, and dissolved Mn fractions associated with particles caught in traps set at 11 depths (50 to 2000 m) were analyzed. Through intentional and unintentional CaCO 3 dissolution 'experiments', it was learned that the weakly leachable Mn was originally in association with the carbonate phase. Adsorption on surfaces rather than absorption in CaCO 3 matrices was indicated by the finding that Mn was not released in proportion to the CaCo 3 dissolved, instead it appeared to keep readsorbing to the dissolving surface. Ultimately, Mn went into solution when the particulate CaCO 3 was essentially depleted, suggesting that sufficient sites for adsorption were no longer available. Manganese fluxes with CaCO 3 were low near the surface (0.1 mg cm -2 ky -1), but increased rapidly in the 50 to 200-m depth interval, and then became more or less constant (1.3 mg cm -2 ky -1 for the remainder of the water column (300 to 2000 m). Rate-of-change estimates indicate that Mn is rapidly scavenged in near-surface waters (-130 ng 1 -1 y -1) and slowly regenerated at depth (2.7 ng 1 -1 y -1) in our near-shore study area. Residence times for dissolved Mn were estimated at 1.2 y for surface waters and 17 y at depth. The implications of Mn transport with CaCO 3 in relation to open-ocean sediment excess Mn are discussed.

  1. Satisfaction of life and late psycho-social outcome after severe brain injury: a nine-year follow-up study in Aquitaine.

    Science.gov (United States)

    Mazaux, J M; Croze, P; Quintard, B; Rouxel, L; Joseph, P A; Richer, E; Debelleix, X; Barat, M

    2002-01-01

    In view of assessing their late outcome and satisfaction of life, 79 out of 158 severe traumatic brain injury (STBI) patients who received inpatient rehabilitation in Aquitaine in 1993 were followed by phone interview. Results showed that 9 years on average after their injury, 65 to 85% of these patients were independent for daily living, whereas 35 to 55% only were independent in social life. Most of the patients were satisfied with their autonomy (67%), family life (66%) and financial status (41%), but they were dissatisfied with leisures (36%), vocational adjustment (28%) and sexual life (32%). Satisfaction of life was mostly related to age, gender, physical autonomy, need of help because of cognitive impairment and functional outcome as assessed by the Glasgow Outcome Scale. Severe traumatic brain injury (STBI) stands in industrialised countries as a major Public Health problem and a dreadful human drama for the patients, their families and the community [2]. A great number of STBI patients survive with severe disability, most of them being young adults. The most severely impaired may live only with their parents or in high-cost nursing homes. From a psychological point of view, STBI causes a total and sudden breakdown of the mental states, personality and conditions of life. Life plans and projects are definitively disrupted, satisfaction of life is deeply changed. Rehabilitation aims at improving functional outcome of persons with STBI, and at improving their overall quality of life. Planning for rehabilitation and re-entry into community of STBI patients need to be provided with precise data on their late outcome and disability level. Despite that the concepts of quality and satisfaction of life are difficult to define and moreover to assess, these are also major factors to take into account. The aims of the present study were to assess the late psycho-social outcome of patients hospitalized in Aquitaine for rehabilitation of a STBI 7 to 10 years after their

  2. NETWORK ENCAPSULATION OF NANOMETER CaCO3

    Institute of Scientific and Technical Information of China (English)

    Wen-fang Liu; Jian Yu; Zhao-xia Guo

    2004-01-01

    The encapsulation of stearic acid coated nanometer CaCO3 by a polystyrene (PS) network via emulsion polymerization is described, where γ-methacryloxypropyltrimethoxysilane (MPS) was used as an efficient crosslinker. The important factors such as the type and amount of surfactant and initiator and the content of CaCO3 are investigated as well as the role of MPS. It has been shown that little PS was extractable with only 0.6 wt% of MPS (relative to styrene). The cationic surfactant cetyl trimethylammonium bromide (CTAB) proved more effective than the anionic surfactant sodium dodecyl sulfonate (SDS). The yield rises, particles become smaller and size distribution broadens with increased amount of CTAB. It is also found that either 2,2′-azobis(isobutyronitrile) (AIBN) or ammonium persulfate (APS) is suitable for attaining high monomer conversion. With increased amount of CaCO3, the encapsulation ratio can be varied from 17.9 to 3.6, while monomer conversion and yield decrease slightly. FT-IR spectra of the products after extraction indicate tight encapsulation between PS and CaCO3, and TEM photographs of composite particles with well-defined core-shell structure give direct evidence of encapsulation.

  3. Validation of modelled imaging plates sensitivity to 1-100 keV x-rays and spatial resolution characterisation for diagnostics for the "PETawatt Aquitaine Laser".

    Science.gov (United States)

    Boutoux, G; Batani, D; Burgy, F; Ducret, J-E; Forestier-Colleoni, P; Hulin, S; Rabhi, N; Duval, A; Lecherbourg, L; Reverdin, C; Jakubowska, K; Szabo, C I; Bastiani-Ceccotti, S; Consoli, F; Curcio, A; De Angelis, R; Ingenito, F; Baggio, J; Raffestin, D

    2016-04-01

    Thanks to their high dynamic range and ability to withstand electromagnetic pulse, imaging plates (IPs) are commonly used as passive detectors in laser-plasma experiments. In the framework of the development of the diagnostics for the Petawatt Aquitaine Laser facility, we present an absolute calibration and spatial resolution study of five different available types of IP (namely, MS-SR-TR-MP-ND) performed by using laser-induced K-shell X-rays emitted by a solid silver target irradiated by the laser ECLIPSE at CEntre Lasers Intenses et Applications. In addition, IP sensitivity measurements were performed with a 160 kV X-ray generator at CEA DAM DIF, where the absolute response of IP SR and TR has been calibrated to X-rays in the energy range 8-75 keV with uncertainties of about 15%. Finally, the response functions have been modeled in Monte Carlo GEANT4 simulations in order to reproduce experimental data. Simulations enable extrapolation of the IP response functions to photon energies from 1 keV to 1 GeV, of interest, e.g., for laser-driven radiography.

  4. Study on Properties of PP/Nano-CaCO3 Composite%PP/Nano-CaCO3复合材料性能的研究

    Institute of Scientific and Technical Information of China (English)

    高岩磊; 陈慧; 郧海丽; 崔文广

    2012-01-01

    PP/nano-CaCO3 composite was prepared by melt blending PP with nano-CaCO3. The effect of the nano-CaCO3 content on mechanical property of the PP/nano-CaC03 composite was studied. The dispersion of the nano-CaCO3 in PP matrix was analyzed by SEM. The results show that: with the increase of content of nano-CaCO3, the impact strength and the tensile strength of the PP/nano-CaCO3 composite both increase firstly and then decrease, but the flexural modulus of the PP/nano-CaCO3 composite increase evidently. The dispersion of the nano-CaCO3 in PP matrix gradually becomes bad with the increase of the content of nano-CaCO3.%采用熔融共混法制备出了聚丙烯(PP)/纳米碳酸钙(nano-CaCO3)复合材料,研究了nano-CaCO3的加入量对复合材料力学性能的影响,利用扫描电镜(SEM)分析了nano-CaCO3在PP基体中的分散性.结果表明:随着nano-CaCO3用量的增加,PP/nano-CaCO3复合材料的冲击强度和拉伸强度均呈现出先增加后降低的趋势,而弯曲模量呈增加趋势;随着填加最的增加,nano-CaCO3在PP基体中的分散性逐渐变差.

  5. Apports alimentaires en acides linoléique et alpha-linolénique d’une population d’Aquitaine

    Directory of Open Access Journals (Sweden)

    Combe Nicole

    2001-03-01

    Full Text Available Les apports alimentaires quotidiens en acides linoléique (18:2 n-6 et alpha-linolénique (18:3 n-3 ont fait récemment l’objet de recommandations pour la population française (ANC 2001. Cependant, peu d’informations sont actuellement disponibles sur la situation réelle, en particulier vis-à-vis du 18:3 n-3. Cette étude montre que la consommation de 18:2 n-6, en Aquitaine (n = 140 femmes, représente en moyenne 4,4 % (± 1,8 de l’apport énergétique total (AET, valeur acceptable par rapport aux ANC (4 %. En revanche, l’apport en 18:3 n-3 est insuffisant (0,34 ± 0,1 % au lieu de 0,8 % recommandé. Dans cette population, le 18:3 n-3 est à 75 % d’origine animale. La contribution des huiles est faible (9 %. La teneur moyenne en 18:2 n-6 et 18:3 n-3 du tissu adipeux des sujets est respectivement égale à 14 % et 0,5 % des acides gras totaux. Dans le plasma, ce sont les esters de cholestérol (EC qui en véhiculent le plus (53 % de 18:2 n-6 et 0,42 % de 18:3 n-3. Cette étude met en évidence une corrélation positive entre les pourcentages de 18:2 n-6 dans les EC plasmatiques et ceux du tissu adipeux (r = 0,606 et p < 0,001, confirmant que cette fraction plasmatique est un « marqueur » non invasif des apports en acide linoléique.

  6. Study on Properties of HDPE/Nano-CaCO3 Composite%HDPE/nano-CaCO3复合材料性能研究

    Institute of Scientific and Technical Information of China (English)

    崔文广; 高岩磊; 刘会茹; 郧海丽

    2012-01-01

    HDPE/nano-CaCO3 composite was prepared by melt blending. The effect of the nano-CaCO3 content on mechanical property of the HDPE/nano-CaCO 3 composite was studied. The dispersion of the nano-CaCOj in HDPE matrix was analyzed by SEM. The results showed that the impact strength and tensile strength of the HDPE/namrCaCO3 composite both increased with the namrCaCO3 content, and then decreased with the nano-CaCOj content, but the flexural modulus of the HDPE/namrCaCO3 composite evidently increased with the nano-CaCO3 content. The dispersion of the nano-CaCO3 in HDPE matrix gradually became bad.%采用熔融共混法制备出了高密度聚乙烯( HDPE)/纳米碳酸钙(nano-CaCO3)复合材料.研究了nano-CaCO3的加入量对复合材料力学性能的影响,利用扫描电镜(SEM)分析了nano-CaCO3在HDPE基体中的分散性.结果表明,随着nano-CaCO3用量的增加,HDPE/nano-CaCO3复合材料的冲击强度和拉伸强度均呈现出先增加后降低的趋势,而弯曲模量呈增加趋势;随着用量的增加,nano-CaCO3在HDPE基体中的分散性逐渐变差.

  7. Photoluminescence Property of Co3O4 Nanowires

    Institute of Scientific and Technical Information of China (English)

    XUE De-Sheng; GONG Yu; LIU Wen-Jing; SI Ming-Su; LIU Zai-Wen

    2007-01-01

    Co3O4 nanowire arrays are fabricated by electrodeposition with following heat-treatment in atmosphere ambient. Photoluminescence is investigated at 295 K. In the experiment, when increasing the excitation light wavelength from 260 nm to 360 nm, two kinds of emissions corresponding to the increasing excitation light wavelength are observed. One of them alters the excited emission position, another keeps its emission position. The distinct behaviour of excited emissions related to the increasing excitation wavelength indicates that the mechanism of them must be different. According to the experimental comparison and first-principle calculation, the two kinds of emissions are discussed.

  8. 不同场景下ANR配置策略及实践%ANR Configuration Stratagem and Application in Different Scenarios

    Institute of Scientific and Technical Information of China (English)

    曹文俊; 郑成林; 钟期洪; 刘悦

    2016-01-01

    Self Organising Network is the very important key technology in LTE system. Automatic Neighbor Relation is a ma-ture technology in LTE SON. By ANR technology the neighbor relation can be realized Self-configuration、Self-optimization and Self-operation in LTE network. ANR technology was used wireless network optimizing in Chinese Telecom Operator’s. In this paper, using different ANR strategies under different scenarios, observe the ANR technology in the LTE network optimiza-tion, optimization for LTE neighbor cell to offer reference to the study and application.%自组织网络SON是4G网络非常重要的一个关键技术(3GPPTS32、3GPP TS36)。ANR是目前比较成熟的SON技术之一,通过ANR可以实现邻区的自配置(Self-configuration)、自优化(Self-optimization)和自操作(Self-operation)。在我国三大运营商的LTE网络中均已将ANR功能上线使用。文章通过在不同场景下使用不同的ANR策略,观察ANR在LTE网络自优化中产生的作用,为LTE邻区优化的学习和应用提供参考。

  9. Influences of polymer coating nano- CaCO3 on the dispersion of nano- CaCO3 in PVC%聚合物包覆对纳米CaCO3在PVC中分散的影响

    Institute of Scientific and Technical Information of China (English)

    包永忠; 史建明; 黄志明; 翁志学

    2005-01-01

    以偶联改性纳米CaCO3和甲基丙烯酸甲酯(MMA)为原料,原位乳液聚合制得PMMA接枝包覆纳米CaCO3,以其与PVC熔融共混制备复合材料,研究了纳米CaCO3在共混体中的分散和与PVC界面的结合.与未改性纳米CaCO3相比,纳米CaCO3接枝包覆PMMA后,在PVC中的分散性能得到明显改善,粒子被分散得更加细小、均匀.PMMA接枝包覆纳米CaCO3与PVC界面间相容性能最好,比小分子改性CaCO3与PVC间的黏结作用更强.采用PMMA包覆纳米CaCO3粒子改性PVC,比未改性纳米CaCO3改性PVC有更好的冲击性能及拉伸性能.

  10. Study on Properties of PP/Nano-CaCO3/EPDM Composite%PP/Nano-CaCO3/EPDM复合材料性能研究

    Institute of Scientific and Technical Information of China (English)

    崔文广; 高岩磊; 刘会茹; 郧海丽

    2013-01-01

    PP/nano-CaCO3/EPDM composite was prepared by melt blending. The effect of the nano-CaCO3 amount and EPDM amount on mechanical property of the PP/nano-CaCO3/EPDM composite were respectively studied. The results showed that the impact strength and tensile strength of the PP/ nano-CaCO3/EPDM composite both increased with the nano-CaCO3 content, and then decreased with the nano-CaCO3 content, and the flexural modulus of the composite increased with the nano-CaCO3 content. The impact strength of the PP/nano-CaCO3/EPDM composite increased with the EPDM content, and the tensile strength and flexural modulus of the PP/nano-CaCO3/EPDM composite both decreased with the EPDM content.%采用熔融共混法制备出了聚丙烯(PP)/纳米碳酸钙(nano-CaCO3)/三元乙丙橡胶(EPDM)复合材料.分别研究了nano-CaCO3和EPDM的加入量对复合材料力学性能的影响.结果表明:随着nano-CaCO3用量的增加,复合材料的冲击强度和拉伸强度均呈现出先增加后降低的趋势,弯曲模量呈增加趋势;随着EPDM用量的增加,复合材料的冲击强度呈增加趋势,拉伸强度和弯曲模量均呈下降趋势.

  11. Metastable Equilibrium in Quaternary System Li2SO4+K2SO4+Li2CO3+K2CO3+H2O at 288 K

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Metastable equilibrium solubilities and densities of the Li2SO4+K2SO4+Li2CO3+K2CO3+H2O system at 288 K were determined experimentally by using the isothermal evaporation method. According to the experimental data, the metastable equilibrium solubility phase diagram was constructed. In the phase diagram, there are three invariate( Li2CO3 ) has the smallest solubility in the quaternary system.

  12. Cobalt Borate Phosphate, Co 3[BPO 7], Synthesis and Characterization

    Science.gov (United States)

    Yilmaz, Aysen; Bu, Xianhui; Kizilyalli, Meral; Kniep, Rudiger; Stucky, Galen D.

    2001-02-01

    Single crystals of Co3[BPO7] were obtained by boron flux method and characterized by single-crystal diffraction data. The compound crystallizes in the monoclinic space group Cm with a=9.774(2), b=12.688(2), c=4.9057(8) Å, β=119.749(2)°; V=528.20(15) Å3; Z=4. The structure consists of Co in trigonal bipyramids, square pyramids, and distorted octahedra. Polyhedral Co centers, triangular B centers, and tetrahedral P centers are joined together to form a three-dimensional network. The temperature dependence of the magnetic susceptibility of the compound follows the Curie-Weiss law to 30 K. Below this temperature, the magnetic behavior displayed first antiferromagnetic ordering followed by ferrimagnetic coupling at 25 K.

  13. The system Na2CO3-CaCO3-MgCO3 at 6 GPa and 900-1250°C and its relation to the partial melting of carbonated mantle

    Science.gov (United States)

    Shatskiy, Anton; Litasov, Konstantin D.; Sharygin, Igor S.; Egonin, Ilya A.; Mironov, Aleksandr M.; Palyanov, Yuri N.; Ohtani, Eiji

    2016-01-01

    In order to constrain the Na2CO3-CaCO3-MgCO3 T-X diagram at 6 GPa in addition to the binary and pseudo-binary systems we conducted experiments along the Na2CO3-Ca0.5Mg0.5CO3 join. At 900-1000°C, melting does not occur and isothermal sections are presented by one-, two- and three-phase regions containing Ca-bearing magnesite, aragonite, Na2CO3 (Na2) and Na2(Ca1-0.9Mg0-0.1)3-4(CO3)4-5 (Na2Ca3-4), Na4(Ca1-0.6Mg0-0.4)(CO3)3 (Na4Ca), Na2(Ca0-0.08Mg1-0.92)(CO3)2 (Na2Mg) phases with intermediate compositions. The minimum melting point locates between 1000°C and 1100°C. This point would resemble that of three eutectics: Mgs-Na2Ca3-Na2Mg, Na2Mg-Na2Ca3-Na4Ca or Na2Mg-Na4Ca-Na2, in the compositional interval of [45Na2CO3.55(Ca0.6Mg0.4)CO3]-[60Na2CO3.40Ca0.6Mg0.4CO3]. The liquidus projection has seven primary solidification phase regions for Mgs, Dol, Arg, Na2Ca3, Na4Ca, Na2 and Na2Mg. The results suggest that extraction of Na and Ca from silicate to carbonate components has to decrease minimum melting temperature of carbonated mantle rocks to 1000-1100°C at 6 GPa and yields Na-rich dolomitic melt with a Na# (Na2O/(Na2O + CaO + MgO)) ≥ 28 mol%.

  14. Magnetic and structural results on (Mn,Co3(Si,P and (Fe,Co3(Si,P alloys

    Directory of Open Access Journals (Sweden)

    J.V. Leitão

    2014-01-01

    Previously reported value for transition temperatures and compositional limits have been found to be incorrect for the (Fe,Co3P system and a novel inverse magnetocaloric effect compound has been discovered as a consequence of the study performed in the (Mn,Co3(Si,P system.

  15. MgCaCO3 Versus CaCO3 in Peritoneal Dialysis Patients – A Cross-Over Pilot Trial

    Science.gov (United States)

    Evsanaa, Baigalmaa; Liu, Irene; Aliazardeh, Babak; Mahdavi, Sara; Bajwa, Gursarn; Gula, Jerry; Tam, Michelle; Sze, Elena; Roscoe, Janet M.; Tam, Paul Y.; Sikaneta, Tabo

    2015-01-01

    ♦ Background: Despite adverse effects such as constipation, vascular calcification, and hypercalcemia, calcium-based salts are relatively affordable and effective phosphate binders that remain in widespread use in the dialysis population. We conducted a pilot study examining whether the use of a combined magnesium/calcium-based binder was as effective as calcium carbonate at lowering serum phosphate levels in peritoneal dialysis (PD) patients. ♦ Methods: This was a cross-over, investigator-masked pilot study in which prevalent PD patients received calcium carbonate alone (200 mg calcium per tablet) or calcium magnesium carbonate (100 mg calcium, 85 mg magnesium per tablet). Primary outcome was serum phosphate level at 3 months. Analysis was as per protocol. ♦ Results: Twenty patients were recruited, 17 completed the study. Mean starting dose was 11.35 ± 7.04 pills per day of MgCaCO3 and 9.00 ± 4.97 pills per day of CaCO3. Mean phosphate levels fell from 2.13 mmol/L to 2.01 mmol/L (95% confidence interval (CI): 1.76 – 2.30, p = 0.361) in the MgCaCO3 group, and 1.81 mmol/L (95% CI: 1.56 – 2.0, p = 0.026) in the CaCO3 alone group. Six (35%) patients taking MgCaCO3 and 9 (54%) taking CaCO3 alone achieved Kidney Disease Outcomes Quality Initiative (KDOQI) serum phosphate targets at 3 months. Diarrhea developed in 9 patients taking MgCaCO3 and 3 taking CaCO3. Serum magnesium exceeded 1.4 mmol/L in 5 patients taking MgCaCO3 while serum calcium exceeded 2.65 mmol/L in 3 patients receiving CaCO3. When compared to the initial dose, the prescribed dose at 3 months was reduced by 44% (to 6.41 tablets/day) in the MgCaCO3 group and by 8% (to 8.24 pills per day) in the CaCO3 alone group. ♦ Conclusion: Compared with CaCO3 alone, the preparation and dose of MgCaCO3 used in this pilot study was no better at lowering serum phosphate levels in PD patients, and was associated with more dose-limiting side effects. PMID:24584605

  16. Characterization of ceramics materials mixed with Co3O4

    Science.gov (United States)

    Guzmán, A. F.; Landínez Téllez, D. A.; Roa-Rojas, J.; Fajardo, F.

    2014-04-01

    We have performed the preparation, structural, electrical and mechanical characterizations of ceramic materials composed of kaolinite Al2(Si2O5)(OH)4 and alumina (Al2O3) mixed with different concentrations of cobalt oxide (Co3O4). Ceramic samples were prepared from a base concentration of alumina 30% and kaolinite 70%, mixed with various concentrations of cobalt oxide in steps of 4% up to a value of 20%. The samples were sintered by the standard solid-state reaction method at a temperature of 1350 °C. In all samples with cobalt was found the presence of mullite. It was determined that alumina and cristobalite decreased when the cobalt concentration was increased due to the formation of the cobalt spinel. In order to determine the crystal structure of the samples, crystallographic analysis from X-ray diffraction experiments and also the semi-quantitative phase analysis were performed. Results were compared with theoretical parameters through the PowderCell 2.4 software. By increasing the concentration of cobalt oxide was found a significant increase in the resistance of materials to friction wear and a small decrease on the mean value of the dielectric constant. Through flexion measurements is observed the increases of the elasticity modulus by about 45% for the sample with 4% of cobalt oxide when compared with the samples without cobalt.

  17. The heat resistance of a polyurethane coating filled with modified nano-CaCO3

    Science.gov (United States)

    Li, Bin; Li, Song-Mei; Liu, Jian-Hua; Yu, Mei

    2014-10-01

    The modification of polyurethane coating by adding surface-modified CaCO3 nanoparticles (nano-CaCO3) was investigated in this paper. To improve interfacial interaction between the nano-CaCO3 and the polyurethane (PU) matrix, a silane coupling agent (KH560) was used to modify the nano-CaCO3. The grafting of KH560 on the nano-CaCO3 surfaces was characterized by the TEM, FTIR and TGA techniques. The modification of the nano-CaCO3 surfaces with KH560 was demonstrated to improve the dispersity of nano-CaCO3. FTIR, SEM and AFM were used to characterize the polyurethane coating. The FTIR spectrum indicated that the modification of nano-CaCO3 does not influence the chemical structure of the PU matrix. The roughness and gloss of the nanocomposite coatings containing various amount of nano-CaCO3 were evaluated using a roughness tester and a brightness meter. The heat resistance of the polyurethane coating containing various amounts of nano-CaCO3 was evaluated using the TGA technique. The results revealed that nano-CaCO3 treatment with KH560 improves the nanoparticle dispersion and heat-resistance of polyurethane coating.

  18. Co3O4 nanoparticles on the surface of halloysite nanotubes

    Science.gov (United States)

    Zhang, Yi; Yang, Huaming

    2012-11-01

    Co3O4 nanoparticles were successfully deposited on the surface of natural halloysite nanotubes (HNTs) to produce Co3O4/HNTs composites. The structure and morphology of the samples were characterized using X-ray diffraction, field-emission scanning electron microscope, transmission electron microscope and Fourier transform infrared. The results indicated that Co3O4 nanoparticles were uniformly attached on the surface of HNTs with narrow size distribution. Co3O4/HNTs exhibited an excellent photocatalytic efficiency for degradation of methyl blue under UV light, better than Co3O4 and HNTs mixture, HNTs and pure Co3O4. The mechanism of enhanced photocatalytic activity of Co3O4/HNTs was also proposed.

  19. Identification of anrF gene, a homology of admM of andrimid biosynthetic gene cluster related to the antagonistic activity of Enterobacter cloacae B8

    Institute of Scientific and Technical Information of China (English)

    Xu-Ping Yu; Jun-Li Zhu; Xue-Ping Yao; Shi-Cheng He; Hai-Ning Huang; Wei-Liang Chen; Yong-Hao Hu; De-Bao Li

    2005-01-01

    AIM: To identify the gene (s) related to the antagonistic activity of Enterobacter cloacae B8 and to elucidate its antagonistic mechanism.METHODS: Transposon-mediated mutagenesis and tagging method and cassette PCR-based chromosomal walking method were adopted to isolate the mutant strain(s) of B8 that lost the antagonistic activity and to clone DNA fragments around Tn5 insertion site. Sequence compiling and open reading frame (ORF) finding were done with DNAStar program and homologous sequence and conserved domain searches were performed with BlastN or BlastP programs at www. ncbi.nlm.nih.gov. To verify the gene involved in the antagonistic activity, complementation of a full-length clone of the anrFgene to the mutant B8F strain was used.RESULTS: A 3 321 bp contig around the Tn5 insertion site was obtained and an ORF of 2 634 bp in length designated as anrFgene encoding for a 877 aa polyketide synthase-like protein was identified. It had a homology of 83% at the nucleotide level and 79% ID/87% SIM at the protein level, to the admM gene of Pantoea agglornerans andrimid biosynthetic gene cluster (AY192157). The Tn5was inserted at 2 420 bp of the gene corresponding to the COG3319 (the thioesterase domain of type Ⅰ polyketide synthase) coding region on B8F. The antagonistic activity against Xanthomonas oryzae pv. oryzae was resumed with complementation of the full-length anrFgene to the mutant B8F.CONCLUSION: The anrFgene obtained is related to the antagonistic activity of B8, and the antagonistic substances produced by B8 are andrimid and/or its analogs.

  20. Complex magnetic couplings in Co3TeO6

    Science.gov (United States)

    Wang, Chin-Wei; Lee, Chi-Hung; Li, Chi-Yen; Wu, Chun-Ming; Li, Wen-Hsien; Chou, Chih-Chieh; Yang, Hung-Duen; Lynn, Jeffrey W.; Huang, Qingzhen; Harris, A. Brooks; Berger, Helmuth

    2013-11-01

    We report powder and single-crystal neutron diffraction measurements, combined with x-ray powder diffraction data, to unravel the complex magnetic phase diagram and exchange coupling in Co3TeO6. The magnetic structures of the various phases differ markedly from those proposed by Ivanov [Mater. Res. Bull.MRBUAC0025-540810.1016/j.materresbull.2011.10.003 47, 63 (2012)] on the basis of only powder diffraction data. The dominant exchange interactions are identified by considering the geometrical arrangement of severely distorted CoO6 octahedra and CoO4 tetrahedra, which naturally divide into two different types of layers, one of which consists of zigzag chains. These zigzag chains are the first to develop magnetic order at TM1 = 26 K, which is incommensurate in nature. The other separate layer of Co spins develops antiferromagnetic order of Γ4 symmetry at zero wave vector at TM2 = 19.5 K. Our results are consistent with the previous findings of a spontaneous polarization below TM3 = 18 K. Our neutron powder diffraction data indicate that the increase in the single-crystal (600) Bragg peak is due to a relief of extinction rather than to magnetic effects associated with the observed anomalous variation in the incommensurate wave vector at TM4 = 16 K. The commensurate order parameter is shown to have a small dependence on the applied electric field, whereas no such effect is found for the incommensurate ordering. Below TM3, the thermal expansion is negative, and it also exhibits anomalies at TM2 and TM4. A symmetry analysis and comprehensive phase diagram are given.

  1. Study of the Differences of Thermal Stability of Mg-Al-CO3 and Zn-Al-CO3 Hydrotalcite%Mg-Al-CO3与Zn-Al-CO3水滑石热稳定性差异的研究

    Institute of Scientific and Technical Information of China (English)

    李蕾; 张春英; 矫庆泽; 段雪

    2001-01-01

    The structures of Mg-Al-CO3 and Zn-Al-CO3 hydrotalcites have been studied by means of XRD, IR and TG-DTA. Although both have the same crystal structures, their thermal stabilities are quite different. During the thermal decomposition process, Mg-Al-CO3 hydrotalcite exhibits two stepsdesorption of interlayer water occurs at 200℃, followed by dehydroxylation of the brucite-like layers and loss of carbonate at 400℃, Zn-Al-CO3 hydrotalcite decomposes in one step-the desorption of interlayer water, structural water and carbon dioxide occurred at the same time at 200℃. The results of a theoretical study indicate that the bond strengths of OH-CO3-OH and OH-H2O-CO3-OH in Mg-Al-CO3 hydrotalcite are stronger than those in Zn-Al-CO3 hydrotalcite. It has been shown that the thermal stability of Mg-Al-CO3 hydrotalcite is higher than that of Zn-Al-CO3 hydrotalcite

  2. Predicting the flow in the floodplains with evolving land occupations during extreme flood events (FlowRes ANR project

    Directory of Open Access Journals (Sweden)

    Proust Sébastien

    2016-01-01

    Full Text Available Flood hazards (flow depth and velocity must be accurately assessed in high-risk areas during extreme flood events. However, the prediction of the very high flows is not an easy task due to the lack of field data and to the strong link between flow resistance and the land occupation of the floodplain. Confinement and inhomogeneity in lateral and longitudinal directions of hydraulic roughness strongly vary with return period T. The physical processes are complex, some still largely unexplored, and the assumptions linked to numerical modelling cannot be validated without field data. The FlowRes project (2015-2018, funded by the French National Research Agency (ANR, aims at improving the flood hazard assessment in floodplains in: 1 investigating in laboratory the hydrodynamic structure associated with extreme flood flows for various land occupations and flow discharge magnitudes; 2 assessing if the existing numerical modelling practices used for T ~ 100 years are still valid for extreme events with T > 1000 years, relying on the experimental data and on one field case. This paper reports some results obtained during the first year of the project.

  3. Carbon Dioxide Activation by Scandium Atoms and Scandium Monoxide Molecules: Formation and Spectroscopic Characterization of ScCO3 and OCScCO3 in Solid Neon.

    Science.gov (United States)

    Zhang, Qingnan; Qu, Hui; Chen, Mohua; Zhou, Mingfei

    2016-01-28

    The reactions of carbon dioxide with scandium monoxide molecules and scandium atoms are investigated using matrix isolation infrared spectroscopy in solid neon. The species formed are identified by the effects of isotopic substitution on their infrared spectra as well as density functional calculations. The results show that the ground state ScO molecule reacts with carbon dioxide to form the carbonate complex ScCO3 spontaneously on annealing. The ground state Sc atom reacts with two carbon dioxide molecules to give the carbonate carbonyl complex OCScCO3 via the previously reported OScCO insertion intermediate on annealing. The observation of these spontaneous reactions is consistent with theoretical predictions that both the Sc + 2CO2 → OCScCO3 and ScO + CO2 → ScCO3 reactions are thermodynamically exothermic and are kinetically facile, requiring little or no activation energy.

  4. NBR Modified PVC/nano-CaCO3 Composites%NBR改性PVC/nano-CaCO3复合材料的研究

    Institute of Scientific and Technical Information of China (English)

    邓月义; 代云水; 况波; 赵树高

    2007-01-01

    将NBR、PVC及纳米CaCO3熔融复合以增韧PVC/纳米CaCO3复合材料.研究了复合材料的力学性能、流变性能、热性能及微观形态.结果显示:NBR对PVC/纳米CaCO3具有增韧效果,材料的断裂伸长率明显增大,PVC/NBR/nano-CaCO3为100/12/8时冲击强度最大,达到了30kJ/m2,比对应的单独纳米CaCO3增韧的PVC提高了大约27%.NBR能降低PVC/CaCO3复合材料的熔体黏度,复合材料加工性能改善.同时NBR的加入使得复合材料的玻璃化转变温度降低,热稳定性变差.扫描电镜照片显示,PVC/NBR/nano-CaCO3为100/12/8时,NBR的加入提高了CaCO3的纳米级分散程度,冲击断面出现了纤维状形变,使得复合材料的冲击强度提高.

  5. The Effect of Ionic Liquids on the CaCO3 Crystal Growth

    Institute of Scientific and Technical Information of China (English)

    Zhi Guo HU; Shi Li SONG; Jian Ji WANG; Lin YANG

    2004-01-01

    In this paper, the effect of ionic liquids on the CaCO3 crystal growth has been studied for the first time. The obtained CaCO3 crystals were charactered by the X-ray diffraction and scanning electron micrographs. The results showed that the control ability of ionic liquids for CaCO3 crystals growth was dependent on the counter anion very much.

  6. Toughening PVC with VC-BA/nano-CaCO3 masterbatch%VC-BA/纳米CaCO3复合母粒增韧PVC

    Institute of Scientific and Technical Information of China (English)

    王士财; 李宝霞; 楼涛; 张晓东

    2007-01-01

    采用氯乙烯-丙烯酸丁酯共聚弹性体(VC-BA)和经表面处理的纳米碳酸钙(nano-CaCO3)制备VC-BA/nano-CaCO3复合母粒,再用该复合母粒与聚氯乙烯(PVC)共混,制备了VC-BA/nano-CaCO3复合母粒增韧的PVC复合材料.复合母粒中m(VC-BA)/m(nano-CaCO3)为2 : 3时,增韧效果最佳.nano-CaCO3与VC-BA有协同增韧作用,且nano-CaCO3能够补强.当PVC和复合母粒质量比为100:20时,材料的冲击强度达到49.5 kJ/m2,是纯PVC的10 倍,拉伸强度为51.0 MPa.

  7. Local structure and magnetism of Co3 + in wurtzite Co:ZnO

    Science.gov (United States)

    Henne, Bastian; Ney, Verena; Lumetzberger, Julia; Ollefs, Katharina; Wilhelm, Fabrice; Rogalev, Andrei; Ney, Andreas

    2017-02-01

    The structural and magnetic properties of 30% and 50% Co-doped ZnO have been investigated in order to determine the influence of the presence of Co3 + as a potential p -type dopant. For 30% doping, Co3 + could be stabilized in the wurtzite lattice of ZnO without phase separation by providing high oxygen partial pressures during growth. At 50% Co concentration, the crystal lattice destabilizes. X-ray absorption spectroscopy and simulations are used to substantiate the valence and local structure of Co3 +. Integral and element selective magnetometry reveals uncompensated antiferromagnetism of the Co atoms irrespective of being present as Co2 + or Co3 +.

  8. SURFACE MODIFICATION OF CaCO3 WITH DENDRITIC CARBOXYLIC ACIDS

    Institute of Scientific and Technical Information of China (English)

    Zhao-xia Guo; Jian Yu

    2002-01-01

    Nanometer calcium carbonate was modified with Frechet type polyether dendrons bearing a COOH group at the focal point by a wet-coating technique in dichloromethane at room temperature. The interaction between CaCO3 and the dendritic modifier was proven by IR and mass spectroscopy of the modified CaCO3 after thorough extraction with dichloromethane. The amount of tightly bonded organic modifier was estimated by TGA. It was shown that the amount of bonded molecules decreased with increasing generation number due to the larger number of branches. Compared to unmodified CaCO3, the modified CaCO3 possess different dispersibility in water and in organic solvents.

  9. Subsolidus and melting phase relations in the system CaCO3-MgCO3-FeCO3 at 35 kbar: from experiments to predictions based on a thermodynamic model

    Science.gov (United States)

    Franzolin, E.; Schmidt, M. W.; Poli, S.

    2009-12-01

    At convergent margins volatile components, most notably CO2 and H2O, stored in oceanic sediments and MORB are recycled into the mantle. Mafic protoliths become enriched in CO2 and H2O, stored in carbonates and hydrous phases, by hydrothermal alteration. As carbonates are more refractory than hydrous phases, CO2 is more likely to survive in the oceanic lithosphere beyond sub-arc depths [1,2]. Despite the main role of carbonates on cycling crustal and atmospheric CO2 into the mantle, experimental data within the system CaCO3-MgCO3-FeCO3 are scarce. To bridge this gap, piston-cylinder experiments have been performed at 35 kbar, 900-1100 °C to determine subsolidus relations, and up to 1300 °C to constrain melting relations. Pure synthetic calcite, natural magnesite and synthetic siderite have been mixed in different proportions in double Pt-C capsules, to avoid major siderite oxidation. Subsolidus experiments reveal the presence of two miscibility gaps at 900 °C: the solvus dolomite-calcite, which closes at XMgCO3 ~ 0.7, and the solvus dolomite-magnesite, which ranges to the Fe-side of the ternary. Increasing the temperature, the two miscibility gaps became narrower until complete solid solutions between CaCO3-Ca0.5Mg0.5CO3 at 1100 °C, and between CaCO3-FeCO3 at 1000 °C, are observed. The system is characterized by strong compositional asymmetry, thermodynamically described with a van Laar macroscopic formalism [3], and by R-3R-3c phase transitions due to cation disordering, treated by redefining the compositional space with an independent set of end-members that describe both composition and states of ordering. The result is a solid solution model able to reproduce both the phase relations experimentally observed at 35 kbar and those experimentally determined and naturally observed at lower pressure [4-5]. Our model can be reliable extended to pressures of the breakdown of dolomite, e.g. 5-6 GPa, 600-1000 °C. Melting experiments carried out at 1250 °C along the

  10. Preparation and Characterization of Battery Grade Co3O4%电池级Co3O4的制备与表征

    Institute of Scientific and Technical Information of China (English)

    丁春桃; 莫祥银; 王克宇; 沈健

    2008-01-01

    以CoCl2·6H2O和NH4HCO3为原料,采用沉淀焙烧法制备电池级Co3O4. 对合成过程的pH值、时间、温度、加料比以及对前躯体Co2(OH)2CO3的焙烧时间和温度进行了系统的研究,得出了最佳的制备条件:以n(CoCl2·6H2O): n(NH4HCO3)=1: 2.5,在温度80 ℃左右反应,pH值在8~9,搅拌反应20 min,生成前驱体Co2(OH)2CO3,100 ℃烘干,600~820 ℃焙烧8 h左右得纯相的Co3O4粉体. 用ICP-AES、XRD、SEM/EDS、FT-IR、LGA、TG/DSC等分析测试技术对Co3O4粉体进行了表征. 结果表明,Co3O4的粒径在4~10 μm,平均粒径为7.3 μm,比表面积为1.05 m 2/g,粒径分布均匀,呈多面体形、类球形颗粒,杂质元素含量低,满足了电池级Co3O4的要求.

  11. Insights into Reaction Mechanism of Na2CO3 in Foaming Process of Cullet Powder

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Smedskjær, Morten Mattrup;

    Soda (Na2CO3) is one of the major raw materials for producing most of the daily used glasses. It often acts as effective fluxing agent in glass melting and foaming agent for producing lightweight glass materials due to its release of CO2 at elevated temperatures. When Na2CO3 is added to a batch...

  12. Synthesis of Co/Co3O4 Nanocomposite Particles Relevant to Magnetic Field Processing

    DEFF Research Database (Denmark)

    Srivastava, A.K.; Madhavi, S.; Menon, Mohan

    2010-01-01

    Co/Co3O4 nanocomposite particles of various morphologies were synthesized by the reverse micelle technique. Equiaxed, rod and faceted crystals with rectangular, pentagonal and hexagonal cross sections were observed. Annealing resulted in the formation of a composite of cobalt oxide (Co3O4) and fcc...

  13. A Novel Biomass Supported Na2CO3 System for Flue Gas Desulfurization

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The breakthrough and stoichiometric SO2 adsorption efficiencies of a biomass supported Na2CO3 system (80 wt %Na2CO3/straw) have reached 48.9 % and 80.6 % respectively at a desulfurization temperature of 80(C.

  14. N-doped nanoporous Co3O4 nanosheets with oxygen vacancies as oxygen evolving electrocatalysts

    Science.gov (United States)

    Xu, Lei; Wang, Zhimin; Wang, Jialu; Xiao, Zhaohui; Huang, Xiaobing; Liu, Zhigang; Wang, Shuangyin

    2017-04-01

    Developing highly active electrocatalysts for the oxygen evolution reaction (OER) with a high surface area, high catalytic activity, low cost and high conductivity is a big challenge for various energy technologies. Herein, for the first time, we realized the simultaneous nitrogen doping and etching of Co3O4 nanosheets to produce N-doped nanoporous Co3O4 nanosheets with oxygen vacancies by N2 plasma. The increase in active sites in N-doped Co3O4 nanosheets and improved electronic conductivity with N doping and oxygen vacancies results in excellent electrocatalytic activity for the OER. Compared with pristine Co3O4 nanosheets, the N-doped Co3O4 nanosheets with oxygen vacancies have a much lower required potential of 1.54 V versus a reversible hydrogen electrode than the pristine Co3O4 nanosheets (1.79 V) to reach the current density of 10 mA cm‑2. The N-doped and etched Co3O4 nanosheets have a much lower Tafel slope of 59 mV dec‑1 than pristine Co3O4 nanosheets (234 mV dec‑1). The enhanced electrocatalytic activity for the OER is caused by the increased surface area, N doping and the produced oxygen vacancies.

  15. Room Temperature Ammonia Gas Sensing Characteristics of Co3O4

    Directory of Open Access Journals (Sweden)

    P.N. Shelke

    2011-01-01

    Full Text Available Room temperature ammonia gas-sensing characteristics of Co3O4 pellet sensor are reported in this paper. For this purpose, Co3O4 powder is prepared by a route of simple precipitation + heating at 800 °C/2 hr. The as-prepared powder is characterized by using X-ray diffraction and scanning electron microscopy. The ammonia gas-sensing properties of Co3O4 pellets made at various loads of 3, 5, 7 & 9 ton and at constant time = 4 min. are measured using home-built static gas sensing system. The characterization studies revealed that the cobalt oxide particles formed are cubic spinel Co3O4, highly pure and spherical in shape. The particle size distribution is found to be nearly uniform with average particle size ~ 1 µm. The ammonia gas sensing properties of Co3O4 pellet sensor are found to be good. The highest sensitivities – S.F. = 175 and 358 are found at ~ 25 ppm and 250 ppm concentrations of ammonia gas respectively for the Co3O4 pellet sensor made at the load = 3 ton. Further, an admirable repeatability and reversibility in the ammonia gas sensing characteristics are observed for all the Co3O4 pellet sensors. The average response time of 4.0 min. and recovery time of 3.0 min. are obtained for all the Co3O4 pellet sensors.

  16. Co3O4(100) films grown on Ag(100): Structure and chemical properties

    Science.gov (United States)

    Arman, Mohammad A.; Merte, Lindsay R.; Lundgren, Edvin; Knudsen, Jan

    2017-03-01

    Spinel type Co3O4(100) is successfully grown on Ag(100) at ultrahigh vacuum conditions and its structure, electronic and chemical properties are compared with those of Co3O4(111) grown on Ir(100). We find that the Co3O4(100) is unreconstructed. In contrast to the defect free Co3O4(111) surface the Co3O4(100) surface contains a high concentration of defects that we assign to subsurface cation vacancies analogous to those observed for Fe3O4(100). Our photoemission and absorption spectroscopy experiments reveal a very similar electronic structure of the Co3O4(111) and Co3O4(100) surfaces. The similar electronic structure of the two surfaces is reflected in the CO adsorption properties at low temperatures, as we observe adsorption of molecular CO as well as the formation of carbonate (CO3) species on both surfaces upon CO exposure at 85 K.

  17. A novel method to synthesize cobalt oxide (Co3O4) nanowires from cobalt (Co) nanobowls

    DEFF Research Database (Denmark)

    Srivastava, Akhilesh Kumar; Madhavi, S.; Ramanujan, R.V.

    2010-01-01

    A novel method suitable for the synthesis of the cobalt oxide (Co3O4) nanowires at targeted regions is presented in this report. Cobalt (Co) nanobowls synthesized by colloidal crystal directed assembly were transformed into Co3O4 nanowires by a simple heat treatment process. Co nanobowls exhibited...

  18. The Improvement of Recycled Newsprint Properties by In-situ CaCO3 Loading

    Directory of Open Access Journals (Sweden)

    Yung Bum Seo

    2014-08-01

    Full Text Available In-situ CaCO3 loading of old newspaper (ONP fiber furnish was studied as a method to improve the properties of recycled newsprint paper. The effects of in-situ loading on the morphological and physical properties of ONP furnish were examined comparatively with conventional loading methods (addition of ground or precipitated CaCO3, without and with pre-flocculation treatment. The effective residual ink content (ERIC and macro sticky content began to decrease as soon as the in-situ CaCO3 formation started by the injection of carbon dioxide to the reaction tank, where the ONP furnish and calcium oxide mixture was agitated in high shear. When the reaction finished at pH 7, there were no more decreases of ERIC value and sticky content. Improvement of first pass retention and brightness was significant for the in-situ CaCO3 loading method. The decrease in breaking length with the addition of CaCO3 in the in-situ formation method was equivalent to or slightly lower than that of the CaCO3 pre-flocculation method, which is a method well known to give higher strength properties. Optical images from the FlowCAM® dynamic imaging particle analyzer showed strongly attached organic (fines and inorganic (CaCO3 materials in the in-situ CaCO3 loading method.

  19. CD4 dynamics over a 15 year-period among HIV controllers enrolled in the ANRS French observatory.

    Directory of Open Access Journals (Sweden)

    Faroudy Boufassa

    Full Text Available BACKGROUND: There are few large published studies of HIV controllers with long-term undetectable viral load (VL. We describe the characteristics and outcomes of 81 French HIV controllers. METHODS AND RESULTS: HIV controllers were defined as asymptomatic, antiretroviral-naïve persons infected ≥10 years previously, with HIV-RNA 90% of plasma samples. All available CD4 and VL values were collected at enrolment. Mixed-effect linear models were used to analyze CD4 cell count slopes since diagnosis. HIV controllers represented 0.31% of all patients managed in French hospitals. Patients infected through intravenous drug use were overrepresented (31% and homosexual men were underrepresented (26% of men relative to the ANRS SEROCO cohort of subjects diagnosed during the same period. HIV controllers whose VL values were always below the detection limit of the assays were compared with those who had rare "blips" (50% of VL values above the detection limit. Estimated CD4 cell counts at HIV diagnosis were similar in the three groups. CD4 cell counts remained stable after HIV diagnosis in the "no blip" group, while they fell significantly in the two other groups (-0.26√CD4 and -0.28√CD4/mm(3/year in the rare and frequent blip groups, respectively. No clinical, immunological or virological progression was observed in the no blip group, while 3 immunological and/or virological events and 4 cancers were observed in the blip subgroups. CONCLUSIONS: Viral blips in HIV controllers are associated with a significant decline in CD4 T cells and may be associated with an increased risk of pathological events, possibly owing to chronic inflammation/immune activation.

  20. Sol-gel preparation and characterization of Co3O4 nanocrystals

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A new citrate acid-hydrazine sol-gel route for preparation of Co3O4 nanoparticles has been developed. Co3O4 nanoparticles with different particle-sizes and morphology were prepared at different heat-treatment temperatures and the pure cubic nanocrystals of Co3O4 were obtained at 600℃. The synthesis process was monitored by infrared spectroscopy (IR), thermal gravimetric and differential thermal analysis (TG-DTA). The structure and morphology of Co3O4 nanocrystals were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and X-ray-photoelectron spectroscopy (XPS). The infrared absorption bands blueshifted with particle size decreasing, which could be attributed to increasing surface effect. XPS results showed that predominant species at surface layers of Co3O4 nanocrystals are octahedral Co (Ⅲ).

  1. Preparation, characterization, viscosity and thermal conductivity of CaCO3 aqueous nanofluids

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    CaCO3 aqueous nanofluids were prepared by dispensing aqueous CaCO3 paste into distilled water under ultrasonic vibration. The actual microstructures of the CaCO3 nanofluids with different particle volume fractions were characterized by freeze etching replication transmission electron microscopy (FERTEM). Thermal conductivity and rheological behavior of the nanofluids were measured by standard analyzers. The results show that CaCO3 paste as raw material for nanofluids is advantageous to reducing aggregation of primary nanoparticles. The effective viscosities and effective thermal conductivities of the CaCO3 nanofluids are related to the aggregates of nanoparticles and can be well predicted by the modified Krieger & Dougherty formula and the modified Hamilton & Crosser model, respectively.

  2. Online fibre optic OSL in vivo dosimetry for quality assurance of external beam radiation therapy treatments: The ANR-TECSAN Codofer Project; Dosimetrie in vivo par OSL, en ligne par fibre optique, pour l'assurance qualite des traitements par radiotherapie externe: le projet ANR-TECSAN Codofer

    Energy Technology Data Exchange (ETDEWEB)

    Magne, S.; Ferdinand, P. [CEA Saclay, Laboratoire de mesures optiques, CEA LIST, 91191 Gif-sur-Yvette (France); De Carlan, L. [CEA Saclay, Laboratoire national Henri-Becquerel, CEA LIST, 91191 Gif-sur-Yvette (France); Bridier, A.; Isambert, A. [Service de physique, institut Gustave-Roussy, 39, rue Camille-Desmoulins, 94805 Villejuif (France); Hugon, R. [CEA Saclay, Departement capteur, signal et informations, CEA LIST, 91191 Gif-sur-Yvette (France); Guillon, J. [Societe Fimel, 18, rue Marie-et-Pierre-Curie, 92260 Fontenay-aux-Roses (France)

    2010-05-15

    The Codofer Project (2007-2009), led under the ANR-TECSAN Call, was coordinated by CEA LIST, in partnership with IGR and the Fimel company. The aim of the project was to design and test both metrologically and in clinical conditions OSL optical fiber sensors dedicated to in vivo dosimetry during external beam radiation therapy treatment with high-energy electrons. This study, combined with the results of clinical tests obtained within the European Project Maestro, has demonstrated the advantages of OSL/FO dosimetry for providing quality assurance of treatments. However, the French market for dosimetry has greatly changed as a result of the rules decreed by the French government in 2007. The OSL/FO product is now targeted for other treatment modalities lacking suitable dosimeters (ANR-INTRADOSE Project [2009-2011]). (authors)

  3. PP/POE/CaCO3复合材料的性能研究%Study on Property of PP/POE/CaCO3 Composites

    Institute of Scientific and Technical Information of China (English)

    杨旸; 邬素华

    2007-01-01

    采用熔融共混工艺制备了聚丙烯/聚烯烃弹性体/碳酸钙(PP/POE/CaCO3)复合材料,研究了POE及CaCO3用量对复合材料力学性能、流变性能及热性能的影响.结果表明:随着POE含量的增加,复合材料的冲击强度显著增大,当POE含量为12%寸,冲击强度较纯PP增加233%;同时拉伸强度随POE含量的增加缓慢下降.随着CaCO3含量增加,冲击强度先增加后缓慢下降.

  4. Enhanced biohydrogen production from sugarcane bagasse by Clostridium thermocellum supplemented with CaCO3.

    Science.gov (United States)

    Tian, Qing-Qing; Liang, Lei; Zhu, Ming-Jun

    2015-12-01

    Clostridium thermocellum ATCC 27405 was used to degrade sugarcane bagasse (SCB) directly for hydrogen production, which was significantly enhanced by supplementing medium with CaCO3. The effect of CaCO3 concentration on the hydrogen production was investigated. The hydrogen production was significantly enhanced with the CaCO3 concentration increased from 10mM to 20mM. However, with the CaCO3 concentration further increased from 20mM to 100mM, the hydrogen production didn't increase further. Under the optimal CaCO3 concentration of 20mM, the hydrogen production reached 97.83±5.19mmol/L from 2% sodium hydroxide-pretreated SCB, a 116.72% increase over the control (45.14±1.03mmol/L), and the yield of hydrogen production reached 4.89mmol H2/g SCBadded. Additionally, CaCO3 promoted the biodegradation of SCB and the growth of C. thermocellum. The stimulatory effects of CaCO3 on biohydrogen production are mainly attributed to the buffering capacity of carbonate. The study provides a novel strategy to enhance biohydrogen production from lignocellulose.

  5. Influence of a threonine residue in the S2 ligand binding domain in determining agonist potency and deactivation rate of recombinant NR1a/NR2D NMDA receptors.

    Science.gov (United States)

    Chen, Philip E; Johnston, Alexander R; Mok, M H Selina; Schoepfer, Ralf; Wyllie, David J A

    2004-07-01

    NR1/NR2D NMDA receptors display unusually slow deactivation kinetics which may be critical for their role as extrasynaptic receptors. A threonine to alanine point mutation has been inserted at amino acid position 692 of the NR2D subunit (T692A). Recombinant NR1a/NR2D(T692A) NMDA receptors have been expressed in Xenopus laevis oocytes and their pharmacological and single-channel properties examined using two-electrode voltage-clamp and patch-clamp recording techniques. Glutamate dose-response curves from NR1a/NR2D(T692A) receptor channels produced an approximately 1600-fold reduction in glutamate potency compared to wild-type NR1a/NR2D receptors. There was no change in Hill slopes or gross reduction in mean maximal currents recorded in oocytes expressing either wild-type or mutant receptors. The mutation did not affect the potency of the co-agonist glycine. The shifts in potency produced by NR2D(T692A) containing receptors when activated by other glutamate-site agonists such as aspartate or NMDA were 30- to 60-fold compared to wild-type. Single-channel conductance levels of NR1a/NR2D(T692A) mutant receptors were indistinguishable from wild-type NR2D-containing channels. Additionally NR1a/NR2D(T692A) receptors showed the transitional asymmetry that is characteristic of NR2D-containing NMDA receptors. Rapid applications of glutamate on outside-out patches containing NR1a/NR2D(T692A) receptors produced macroscopic current deactivations that were about 60-fold faster than wild-type NR1a/NR2D receptors. Our results suggest that this conserved threonine residue plays a crucial role in ligand binding to NMDA NR2 receptor subunits and supports the idea that the slow decay kinetics associated with NR1a/NR2D NMDA receptors can be explained by the slow dissociation of glutamate from this NMDA receptor subtype.

  6. Factors associated with negative direct sputum examination in Asian and African HIV-infected patients with tuberculosis (ANRS 1260.

    Directory of Open Access Journals (Sweden)

    Loïc Chartier

    Full Text Available OBJECTIVE: To identify factors associated with negative direct sputum examination among African and Cambodian patients co-infected by Mycobacterium tuberculosis and HIV. DESIGN: Prospective multicenter study (ANRS1260 conducted in Cambodia, Senegal and Central African Republic. METHODS: Univariate and multivariate analyses (logistic regression were used to identify clinical and radiological features associated with negative direct sputum examination in HIV-infected patients with positive M. tuberculosis culture on Lowenstein-Jensen medium. RESULTS: Between September 2002 and December 2005, 175 co-infected patients were hospitalized with at least one respiratory symptom and pulmonary radiographic anomaly. Acid-fast bacillus (AFB examination was positive in sputum samples from 110 subjects (63% and negative in 65 patients (37%. Most patients were at an advanced stage of HIV disease (92% at stage III or IV of the WHO classification with a median CD4 cell count of 36/mm³. In this context, we found that sputum AFB negativity was more frequent in co-infected subjects with associated respiratory tract infections (OR = 2.8 [95%CI:1.1-7.0], dyspnea (OR = 2.5 [95%CI:1.1-5.6], and localized interstitial opacities (OR = 3.1 [95%CI:1.3-7.6], but was less frequent with CD4 ≤ 50/mm³ (OR = 0.4 [95%CI:0.2-0.90, adenopathies (OR = 0.4 [95%CI:0.2-0.93] and cavitation (OR = 0.1 [95%CI:0.03-0.6]. CONCLUSIONS: One novel finding of this study is the association between concomitant respiratory tract infection and negative sputum AFB, particularly in Cambodia. This finding suggests that repeating AFB testing in AFB-negative patients should be conducted when broad spectrum antibiotic treatment does not lead to complete recovery from respiratory symptoms. In HIV-infected patients with a CD4 cell count below 50/mm3 without an identified cause of pneumonia, systematic AFB direct sputum examination is justified because of atypical clinical

  7. Increased NR2A:NR2B ratio compresses long-term depression range and constrains long-term memory.

    Science.gov (United States)

    Cui, Zhenzhong; Feng, Ruiben; Jacobs, Stephanie; Duan, Yanhong; Wang, Huimin; Cao, Xiaohua; Tsien, Joe Z

    2013-01-01

    The NR2A:NR2B subunit ratio of the NMDA receptors is widely known to increase in the brain from postnatal development to sexual maturity and to aging, yet its impact on memory function remains speculative. We have generated forebrain-specific NR2A overexpression transgenic mice and show that these mice had normal basic behaviors and short-term memory, but exhibited broad long-term memory deficits as revealed by several behavioral paradigms. Surprisingly, increased NR2A expression did not affect 1-Hz-induced long-term depression (LTD) or 100 Hz-induced long-term potentiation (LTP) in the CA1 region of the hippocampus, but selectively abolished LTD responses in the 3-5 Hz frequency range. Our results demonstrate that the increased NR2A:NR2B ratio is a critical genetic factor in constraining long-term memory in the adult brain. We postulate that LTD-like process underlies post-learning information sculpting, a novel and essential consolidation step in transforming new information into long-term memory.

  8. CeO2-Co3O4 Catalysts for CO Oxidation

    Institute of Scientific and Technical Information of China (English)

    Xu Xiuyan; Li Jinjun; Hao Zhengping

    2006-01-01

    CeO2-Co3O4 catalysts for low-temperature CO oxidation were prepared by a co-precipitation method.In combination with the characterization methods of N2 adsorption/desorption, XRD, temperature-programmed reduction (TPR), and FT-IR, the influence of the cerium content on the catalytic performance of CeO2-Co3O4 was investigated.The results indicate that the prepared CeO2-Co3O4 catalysts exhibit a better activity than that of pure CeO2 or pure Co3O4.The catalyst with the Ce/Co atomic ratio 1:16 exhibits the best activity, which converts 77% of CO at room temperature and completely oxidizes CO at 45 ℃.

  9. Foaming of CRT panel glass powder using Na2CO3

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Smedskjær, Morten Mattrup

    2014-01-01

    to its non-hazardous composition. Here we report on the foaming of CRT panel glass using Na2CO3 as the foaming agent. We explore how heat treatment temperature and concentration of Na2CO3 affect the density and porosity of the foam glasses, and whether Na2O is incorporated in the glass network......The recycling of glass from obsolete cathode ray tubes (CRT) has hitherto only occurred to a very limited extent, but the production of foam glass used as an insulation material component has recently been proposed as a promising recycling method. CRT panel glass has high recycling potential due......% Na2CO3 is added and the heat treatment temperature is 1023 K. Interestingly, the glass transition temperature (Tg) of the final foam glass decreases linearly with increasing [Na2CO3], indicating that the Na2O is incorporated into the glass network....

  10. Simulating oceanic CaCO3 export production in the greenhouse

    Science.gov (United States)

    Heinze, C.

    2004-08-01

    A model scenario for the change in global marine biogenic CaCO3 export production (CaCO3 = calcium carbonate) due to increasing atmospheric carbon dioxide partial pressure is carried out. Findings from laboratory experiments, which suggest a decrease of biocalcification at higher pCO2, are extrapolated to the world ocean by use of the biogeochemical ocean general circulation model HAMOCC. For an A1B IPCC emission scenario and constant emission rates after year 2100, the simulation predicts a global decrease of biological CaCO3 export production by about 50% in year 2250. The negative feedback due to this drop in CaCO3 export on the atmospheric CO2 concentration is small as compared to the anthropogenic CO2 emissions. This negative feedback will potentially be compensated by a shallower remineralization of organic carbon.

  11. Graphene-supported ultra-small Co3O4 nanoparticles for high-performance supercapacitors

    Institute of Scientific and Technical Information of China (English)

    LIU Zheng; LI Ji; WU Xiaoliang; WEI Tong; FAN Zhuangjun

    2016-01-01

    Ultra-small Co3O4 nanoparticles/graphene hybrid material had been synthesized by a facile hydrothermal route and consequent calcination process. The as-obtained ultra-small Co3O4 nanoparticles with their sizes of 5–8 nm are tightly anchored on the surface of graphene (GNS). Benefiting from the ultra-small size of Co3O4 nanoparticles, the high interconnectivity of hybrid material as well as the high conductive networks constructed by GNS, which can provide a fast and efficient transportation of electron and electrolyte ions for the overall electrode, the as-prepared hybrid material exhibits a high specific capacitance of 462 F·g-1 at 5 mV·s-1 compared with pure Co3O4 (193 F·g-1), and retained 88.2% of its initial capacitance after 2000 cycles, indicating a promising electrode material for supercapacitors.

  12. Non-enzymatic hydrogen peroxide sensor based on Co3O4 nanocubes

    Indian Academy of Sciences (India)

    Guang Sheng Cao; Lei Wang; Pengfei Yuan; Chao Gao; Xiaojuan Liu; Tong Li; Tianmin Li

    2014-10-01

    The Co3O4 nanocubes were prepared by using hydrogen peroxide (H2O2) as oxidant, Co(NO3)2. 6H2O as a cobalt source. The products were characterized in detail by multiform techniques: scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The prepared Co3O4 nanocubes were applied to study the electrocatalytic reduction of hydrogen peroxide (H2O2) in 0.01 M pH 7.0 phosphate buffer medium. The Co3O4 nanocubes exhibit remarkable electrocatalytic activity for H2O2 reduction. Furthermore, the obtained Co3O4 nanocubes have been employed as electrode materials for electrochemical sensing H2O2.

  13. Highly Crystalline FeCO3 Microparticle Synthesis by Hydrothermal Decomposition of Fe-EDTA Complex

    Science.gov (United States)

    Chirita, M.; Banica, R.; Ieta, A.; Bucur, A.; Sfiarloaga, P.; Ursu, D. H.; Grozescu, I.

    2010-08-01

    In this article, we present an experimental procedure to synthesize highly crystalline FeCO3 by hydrothermal decomposition of Fe(III)-EDTA complex, starting from Ferric Ammonium Sulfate and Na4EDTA main precursors in urea presence. The structure, morphology and composition of the powders were obtained using X-ray powder diffraction and scanning electron microscopy. The peaks were founded, indicate that the synthesized products autoclaved 22 h at 250 °C are pure FeCO3, which was well proved experimentally from EDAX further investigated. The size with appreciatively 100 μm was evaluated by SEM images. Magnetic characterization confirmed the magnetic characteristics of FeCO3. This procedure allowed the FeCO3 microparticles formation with good and stabile crystallographic characteristics.

  14. Authigenic carbonate mounds from active methane seeps on the southern Aquitaine Shelf (Bay of Biscay, France): Evidence for anaerobic oxidation of biogenic methane and submarine groundwater discharge during formation

    Science.gov (United States)

    Pierre, Catherine; Demange, Jérome; Blanc-Valleron, Marie-Madeleine; Dupré, Stéphanie

    2017-02-01

    The widespread methane emissions that were discovered in 2013 on the Aquitaine Shelf at water depth between 140 and 220 m are associated with authigenic carbonate crusts that cover meter-high subcircular reliefs of 10-100 m in diameter. These authigenic carbonates are primarily aragonite plus calcite and dolomite, which cement the fine- to medium-grained sandy sediment. The carbonate cement is often pierced by numerous circular cavities of 5-10 μm in diameter that are considered to be moulds of gas bubbles. Conversely, micron-sized cavities in the aragonite crystals are attributed to dissolution features, in relation to the production of CO2 during the aerobic oxidation of methane. The oxygen isotopic compositions of bulk carbonate (+1.7 to +3.7‰) and aragonite cements obtained from microsampling (-0.1 to +1.4‰) indicate that these carbonates were precipitated in mixtures of seawater and freshwater, i.e., in the context of submarine groundwater discharge at the seafloor. The carbon isotopic compositions of authigenic carbonates (-51.9 to -38.1‰) and of aragonite cements (-49.9 to -29.3‰) show that the dissolved inorganic carbon of pore fluids was mostly produced by the anaerobic oxidation of biogenic methane and also partly from the groundwater system.

  15. Low-temperature Growth of Single-crystal SrCO3 Nanoneedles

    Institute of Scientific and Technical Information of China (English)

    Guang Sheng GUO; Fu Bo GU; Zhi Hua WANG; Hong You GUO

    2005-01-01

    Single-crystal SrCO3 nanoneedles were synthesized in reverse micelles at low temperature. The products were characterized by X-ray diffraction, X-ray energy dispersive spectrometer, transmission electron microscopy and selected area electronic diffraction. The influences of experimental conditions on the morphologies of the products were discussed. The growth mechanism of SrCO3 nanoneedles in reverse micelles were proposed.

  16. Nano—CaCO3改性聚烯烃树脂研究进展%Research of Progress on Modifications of Nano-- CaCO3/polyolefin Composites

    Institute of Scientific and Technical Information of China (English)

    姜鹏; 韩亚魁; 程泰山; 冼以积; 曹新鑫

    2012-01-01

    介绍了nano—CaCO3改性聚丙烯、聚乙烯、聚氯乙烯、苯乙烯和ABS等树脂的力学性能、结晶行为和老化行为等性能的研究进展。并对nano—CaCO3的改性应用和研究方向做了展望。%The modifications of nano-- CaCO3/PP, nano-- CaCO3/PE, nano-- CaCO3 / PVC, nano--CaCO3/PS and nano--CaCO3/ABS as well as the nanocomposites" me- chanical properties, crystallization behavior and ageing behavior were reviewed in this paper. Furthermore, the modified application and research direction of nano--CaCO3 were also prospected.

  17. Enhancement of CO2 sorption uptake on hydrotalcite by impregnation with K2CO3.

    Science.gov (United States)

    Lee, Jung Moo; Min, Yoon Jae; Lee, Ki Bong; Jeon, Sang Goo; Na, Jeong Geol; Ryu, Ho Jung

    2010-12-21

    The awareness of symptoms of global warming and its seriousness urges the development of technologies to reduce greenhouse gas emissions. Carbon dioxide (CO(2)) is a representative greenhouse gas, and numerous methods to capture and storage CO(2) have been considered. Recently, the technology to remove high-temperature CO(2) by sorption has received lots of attention. In this study, hydrotalcite, which has been known to have CO(2) sorption capability at high temperature, was impregnated with K(2)CO(3) to enhance CO(2) sorption uptake, and the mechanism of CO(2) sorption enhancement on K(2)CO(3)-promoted hydrotalcite was investigated. Thermogravimetric analysis was used to measure equilibrium CO(2) sorption uptake and to estimate CO(2) sorption kinetics. The analyses based on N(2) gas physisorption, X-ray diffractometry, Fourier transform infrared spectrometry, Raman spectrometry, transmission electron microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy were carried out to elucidate the characteristics of sorbents and the mechanism of enhanced CO(2) sorption. The equilibrium CO(2) sorption uptake on hydrotalcite could be increased up to 10 times by impregnation with K(2)CO(3), and there was an optimal amount of K(2)CO(3) for a maximum equilibrium CO(2) sorption uptake. In the K(2)CO(3)-promoted hydrotalcite, K(2)CO(3) was incorporated without changing the structure of hydrotalcite and it was thermally stabilized, resulting in the enhanced equilibrium CO(2) sorption uptake and fast CO(2) sorption kinetics.

  18. Influence of Surfactant-polymer Complexes on Crystallization and Aggregation of CaCO3

    Institute of Scientific and Technical Information of China (English)

    PAN Yan; GUO Yu-peng; ZHAO Xu; WANG Zi-chen

    2012-01-01

    Hollow calcium carbonate(CaCO3) microspheres with different morphologies were synthesized via the precipitation reaction of calcium chloride with sodium carbonate in the presence of different surfactant-polymer complexes.The selected anionic surfactants were sodium dodecyl sulfonate(SDS) and sodium dodecyl benzenesulfonate(SDBS),respectively.The selected water-soluble polymers were polyacrylic acid(PAA) and polyvinyl pyrrolidone(PVP).In this work,SDS-PVP "pearl-necklace model" micellar complex was formed via hydrophobic effectiveness between SDS and PVP and it served as the spherical template to generate spherical CaCO3 aggregates with hollow microspheres composed of about 500 nm irregular shaped particles.SDS-PAA complexes and SDBS-PAA complexes formed "core-shell model" aggregates with calcium ions serving as the medium to link the anionic surfactant and the polymer.SDS-PAA "core-shell model" aggregates would act as templates for hollow CaCO3 microspheres consisting of 30-50 nm irregular shaped crystallites.SDBS-PAA "core-shell model" aggregates served as the spherical aggregate templates to generate spherical CaCO3 aggregates consisted of many small spherical particles which had grown together.All the obtained CaCO3 hollow microspheres are calcite particles.This research may provide new insight into the control of morphologies of hollow CaCO3 microspheres in the presence of surfactantpolymer complexes.

  19. Influence of CaCO3 Whisker Content on Mechanical and Tribological Properties of Polyetheretherketone Composites

    Institute of Scientific and Technical Information of China (English)

    Youxi LIN; Chenghui GAO; Ning LI

    2006-01-01

    The mechanical and tribological properties of polyetheretherketone(PEEK)composites filled with CaCO3 whisker in various content of 0~45%(wt pct)were investigated. The composite specimens were prepared by compression molding. Tribological testing of composites in dry wear mode against carbon steel ring was carried out on a MM200 block-on-ring apparatus. Data on neat PEEK were also included for comparison. It was observed that inclusion of CaCO3 whisker affected the most mechanical properties and the friction and wear in a beneficial way. With an increase in CaCO3 whisker content, friction coefficient continuously decreased but the trends in wear performance varied. The specific wear rate showed minima as 1.28×10-6 mm3/Nm for 15% CaCO3 whisker inclusion followed by a slow increase for further CaCO3 whisker addition. In terms of friction applications, when the tribological and mechanical properties are combined, the optimal content of CaCO3 whisker in the filled PEEK should be recommended as 15% to 20%. Fairly good correlations are observed in friction coefficient vs bending modulus and wear rate vs bending strength, confirming that the bending properties prove to be the most important tribology controlling parameters in the present work.

  20. Study of antibacterial activity of Ag and Ag2CO3 nanoparticles stabilized over montmorillonite.

    Science.gov (United States)

    Sohrabnezhad, Sh; Pourahmad, A; Mehdipour Moghaddam, M J; Sadeghi, A

    2015-02-05

    Silver carbonate and silver nanoparticles (NPs) over of stabilizer montmorillonite (MMT) have been synthesized in aqueous and polyol solvent, respectively. Dispersions of silver nanoparticles have been prepared by the reduction of silver nitrate over of MMT in presence and absence of Na2CO3 compound in ethylene glycol. It was observed that montmorillonite was capable of stabilizing formed Ag nanoparticles through the reduction of Ag(+) ions in ethylene glycol. Na2CO3 was used as carbonate source in synthesis of Ag2CO3 NPs in water solvent and also for controlling of Ag nanoparticles size in ethylene glycol medium. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and ultraviolet-visible diffuse reflectance spectroscopy (DRS). The TEM images showed that Ag NPs size in presence Na2CO3 salts was smaller than without that. The results indicated intercalation of Ag and Ag2CO3 nanoparticles into the montmorillonite clay layers. The diffuse reflectance spectra exhibited a strong surface plasmon resonance (SPR) adsorption peak in the visible region, resulting from Ag nanoparticles. The antibacterial testing results showed that the Ag2CO3-MMT nanocomposite exhibited an antibacterial activity higher than Ag-MMT sample against Escherichia coli.

  1. Fe2O3/ Co3O4 composite nanoparticle ethanol sensor

    CERN Document Server

    Mirzaei, Ali; Sun, Gun-Joo; Kheel, Hyejoon; Lee, Sangmin; lee, Chongmu

    2016-01-01

    In this study Fe2O3/Co3O4 nanocomposites were synthesized by using a simple hydrothermal route. The X-ray diffraction analysis results showed that synthesized powders were pure, and nanocrystalline in nature. Moreover, Scanning electron microscopy revealed that Fe2O3 nanoparticles had spherical shapes while Co3O4 particles had a rod-like morphology. Ethanol sensing properties of Fe2O3/Co3O4 nanocomposites were examined and compared with those of pristine Fe2O3 nanoparticles. It was shown that the gas sensing properties of Fe2O3/Co3O4 nanocomposites were superior to those of pristine Fe2O3 nanoparticles and for all concentrations of ethanol, the response of the nanocomposite sensor was higher than the pristine Fe2O3 nanoparticle sensor. In detail, the response of Fe2O3/Co3O4 nanocomposite sensor to 200 ppm of ethanol at 300{\\deg}C was about 3 times higher than pristine one. Also in general, the response and recovery times of Fe2O3/Co3O4 nanocomposite sensor were shorter than those of the pristine one. The impr...

  2. Structural, optical, and magnetic properties of Mn and Fe-doped Co3O4 nanoparticles

    Directory of Open Access Journals (Sweden)

    C. Stella

    2015-08-01

    Full Text Available Mn and Fe-doped Co3O4 nanoparticles were prepared by a simple precipitation method. The synthesized particles were characterized by X-ray diffraction (XRD, scanning electron microscope (SEM, transmission electron microscope (TEM, UV-Vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR, Raman spectroscopy, and vibrating sample magnetometer (VSM techniques. XRD analysis showed the cubic structure of Co3O4. SEM and TEM images confirmed the formation of interconnected nanoparticles. Mn and Fe-doped Co3O4 showed broad absorption in the visible region compared to undoped sample and the band gap values are red shifted. Five Raman active modes were observed from the Raman spectra. FTIR spectra confirmed the spinel structure of Co3O4 and the doping of Mn and Fe shifts the vibrational modes to lower wave number region. The magnetic measurements confirmed that Fe-doped Co3O4 shows a little ferromagnetic behavior compared to undoped and Mn-doped Co3O4, which could be related to the uncompensated surface spins and the finite size effects.

  3. Vacuum ultraviolet excited photoluminescence properties of Gd2O2CO3:Eu3+ phosphor

    Institute of Scientific and Technical Information of China (English)

    WANG Zhilong; WANG Yuhua; ZHANG Jiachi

    2008-01-01

    The Gd2O2CO3:Eu3+ with type-II structure phosphor was successfully synthesized via flux method at 400℃ and their photoluminescence properties in vacuum ultraviolet (VUV) region were examined. The broad and strong excitation bands in the range of 153-205 nm owing to the CO32- host absorption and charge transfer (CT) of Gd3+-O2- were observed for Gd2O2CO3:Eu3+. Under 172 nm excitation, Gd2O2CO3:Eu3+ exhibited strong red emission with good color purity, indicating Eu3+ ions located at low symmetry sites and the chromaticity coordination of luminescence for Gd2O2CO3:Eu3+ was (x=0.652, y=0.345). The photoluminescence quenching concentration of Eu3+ excited by 172 nm for Gd2O2CO3:Eu3+ was about 5%. Gd2O2CO3:Eu3+ would be a potential VUV-excited red phosphor applied in mercury-free fluorescent lamps.

  4. Poly(3-hydroxybutyrate and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate: Structure, Property, and Fiber

    Directory of Open Access Journals (Sweden)

    Qingsheng Liu

    2014-01-01

    Full Text Available Poly(3-hydroxybutyrate [P(3HB] and poly(3-hydroxybutyrate-co-3-hydroxyvalerate [P(3HB-co-3HV] are produced by various microorganisms as an intracellular carbon and energy reserve from agricultural feedstocks such as sugars and plant oils under unbalanced growth conditions. P(3HB and P(3HB-co-3HV have attracted the attention of academia and industry because of its biodegradability, biocompatibility, thermoplasticity, and plastic-like properties. This review first introduced the isodimorphism, spherulites, and molecular interaction of P(3HB and P(3HB-co-3HV. In addition, the effects of 3HV content on the melting temperature and crystallization rate were discussed. Then the drawbacks of P(3HB and P(3HB-co-3HV including brittleness, narrow melt processing window, low crystallization rate, slow biodegradation rate in body, and so on were summarized. At last, the preparation, structure, and properties of P(3HB and P(3HB-co-3HV fiber were introduced.

  5. Synthesis and Microwave Absorption Properties of Core-Shell Structured Co3O4-PANI Nanocomposites

    Directory of Open Access Journals (Sweden)

    Hongyan Xu

    2015-01-01

    Full Text Available The core-shell structured Co3O4-PANI nanocomposites have been successfully prepared using an in situ polymerization method, while the core Co3O4 nanoparticles were synthesized by carbon-assisted method using degreasing cotton as a template. The obtained samples were characterized by XRD, TEM, FTIR, and XPS. The results indicated that the amorphous PANI was well covered on the surface of the spinel Co3O4 and the Co3O4-PANI with core-shell structure was formed with particle size of about 100 nm. The interfacial interaction of the core-shell nanocomposite greatly enhances the microwave absorption properties. The maximum reflection loss of Co3O4-PANI is up to −45.8 dB at 11.7 GHz with a thickness of 2.5 mm and the adsorption bandwidth with the reflection loss below −10 dB reaches 14.1 GHz ranging from 3.9 to 18 GHz when the thickness is between 2 and 5.5 mm. Therefore, the facilely synthesized and low-cost Co3O4-PANI nanocomposite with superior microwave absorption properties can be a promising nanomaterial for high efficient microwave absorption.

  6. Melting relations in the system FeCO3-MgCO3 and thermodynamic modelling of Fe-Mg carbonate melts

    Science.gov (United States)

    Kang, Nathan; Schmidt, Max W.; Poli, Stefano; Connolly, James A. D.; Franzolin, Ettore

    2016-09-01

    To constrain the thermodynamics and melting relations of the siderite-magnesite (FeCO3-MgCO3) system, 27 piston cylinder experiments were conducted at 3.5 GPa and 1170-1575 °C. Fe-rich compositions were also investigated with 13 multi-anvil experiments at 10, 13.6 and 20 GPa, 1500-1890 °C. At 3.5 GPa, the solid solution siderite-magnesite coexists with melt over a compositional range of X Mg (=Mg/(Mg + Fetot)) = 0.38-1.0, while at ≥10 GPa solid solution appears to be complete. At 3.5 GPa, the system is pseudo-binary because of the limited stability of siderite or liquid FeCO3, Fe-rich carbonates decomposing at subsolidus conditions to magnetite-magnesioferrite solid solution, graphite and CO2. Similar reactions also occur with liquid FeCO3 resulting in melt species with ferric iron components, but the decomposition of the liquid decreases in importance with pressure. At 3.5 GPa, the metastable melting temperature of pure siderite is located at 1264 °C, whereas pure magnesite melts at 1629 °C. The melting loop is non-ideal on the Fe side where the dissociation reaction resulting in Fe3+ in the melt depresses melting temperatures and causes a minimum. Over the pressure range of 3.5-20 GPa, this minimum is 20-35 °C lower than the (metastable) siderite melting temperature. By merging all present and previous experimental data, standard state (298.15 K, 1 bar) thermodynamic properties of the magnesite melt (MgCO3L) end member are calculated and the properties of (Fe,Mg)CO3 melt fit by a regular solution model with an interaction parameter of -7600 J/mol. The solution model reproduces the asymmetric melting loop and predicts the thermal minimum at 1240 °C near the siderite side at X Mg = 0.2 (3.5 GPa). The solution model is applicable to pressures reaching to the bottom of the upper mantle and allows calculation of phase relations in the FeO-MgO-O2-C system.

  7. ANR Land Dataset (Unit)

    Data.gov (United States)

    Vermont Center for Geographic Information — The State of Vermont has a long history of acquiring properties for conservation and recreation purposes. Since the first official state forest (L.R. Jones State...

  8. ANR Land Dataset (Parcel)

    Data.gov (United States)

    Vermont Center for Geographic Information — The State of Vermont has a long history of acquiring properties for conservation and recreation purposes. Since the first official state forest (L.R. Jones State...

  9. Applications of Nano-CaCO3 and Mineral Fibres to PVC%纳米CaCO3与矿纤维在PVC中的应用

    Institute of Scientific and Technical Information of China (English)

    蔡梦军; 陈建定; 吴秋芳; 马新胜

    2008-01-01

    研究了纳米CaCO3和矿纤维对聚氯乙烯(PVC)复合材料力学性能的影响.结果表明.在硬质PVC复合材料中填充材料的形状对PVC复合材料的力学性能影响较大,纤维状的矿纤维比球状的纳米CaCO3作为填充材料对硬质PVC复合材料的力学性能明显要高;而在软质PVC复合材料中,填充材料的形状对拉伸性能的影响较小.

  10. Investigation on multiple-melting behavior of nano-CaCO3/polypropylene composites

    Institute of Scientific and Technical Information of China (English)

    LIN Zhidan; ZENG Chunlian; MAI Kancheng

    2007-01-01

    The multiple melting-peak behavior of polypropylene (PP) in nano-CaCO3/PP composites and modified nano-CaCO3/PP composites were investigated under the condition of isothermal crystallization and nonisothermal crystallization.The result indicated that the addition ofnano-CaCO3 markedly increased the crystallization temperatures of PP and induced the formation of the p-crystal of PP.The crystallization temperatures of nano-CaCO3/PP composites modified by reactive monomers were further increased,but the melting-peak intensity of the 13-crystal of PP was not greatly influenced.While in the presence of dicumyl peroxide,nanoCaCO3/PP composites modified by reactive monomers led to the significant increase in the melting-peak intensity of the β-crystal of PP.The double melting-peak of PP was observed,which was attributed to the formation of two kinds of different crystallization forms of or-crystal or β-crystal during the crystallization of PP.With the increase of crystallization temperatures,the double melting-peak moved toward the hightemperature side.The intensity of high-temperature melting peak was higher than that of low-temperature melting peak in nano-CaCO3/PP composites.While in modified nano-CaCO3/PP composites crystallized at higher temperature,the intensity of high-temperature melting peak was lower than that of low-temperature melting peak.The isothermal crystallization time had little effect on the melting temperatures.

  11. BaCO3 mediated modifications in structural and magnetic properties of natural nanoferrites

    Science.gov (United States)

    Widanarto, W.; Jandra, M.; Ghoshal, S. K.; Effendi, M.; Cahyanto, W. T.

    2015-04-01

    Preparing M-type barium hexaferrite and improving the magnetic response of natural ferrites by incorporating barium carbonate (BaCO3) is ever-demanding. Series of barium carbonate doped ferrites with composition (100-x)Fe3O4·xBaCO3 (x=0, 10, 20, 30 wt%) are prepared through solid state reaction method and sintered gradually at temperatures of 800 and 1000 °C. Nanoparticles of natural ferrite and commercial BaCO3 are used as raw materials. Impacts of BaCO3 on structural and magnetic properties of these synthesized ferrites are inspected. The obtained ferrites are characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) at room temperature. Uniform barium hexaferrite particles in terms of both morphology and size are not achieved. The average crystallite size of BaFe12O19 is observed to be within 30-600 nm. The sintering process results phase transformation from Fe3O4 (magnetite) to α-Fe2O3 (hematite) and the formation of hexagonal barium ferrite crystals. The occurrence of barium crystal is found to enhance with the increase of BaCO3 concentrations up to 20 wt% and suddenly drop at 30 wt%. Saturation and remanent magnetization of the doped ferrites are significantly augmented up to 16.37 and 8.92 emu g-1, respectively compared to their pure counterpart. Furthermore, the coercivity field is slightly decreased as BaCO3 concentrations are increased. BaCO3 mediated improvements in the magnetic response of natural ferrites are demonstrated.

  12. Nanoparticle Decorated Ultrathin Porous Nanosheets as Hierarchical Co3O4 Nanostructures for Lithium Ion Battery Anode Materials

    DEFF Research Database (Denmark)

    Mujtaba, Jawayria; Sun, Hongyu; Huang, Guoyong;

    2016-01-01

    We report a facile synthesis of a novel cobalt oxide (Co3O4) hierarchical nanostructure, in which crystalline core-amorphous shell Co3O4 nanoparticles with a bimodal size distribution are uniformly dispersed on ultrathin Co3O4 nanosheets. When tested as anode materials for lithium ion batteries...

  13. Role of baseline HIV-1 DNA level in highly-experienced patients receiving raltegravir, etravirine and darunavir/ritonavir regimen (ANRS139 TRIO trial.

    Directory of Open Access Journals (Sweden)

    Charlotte Charpentier

    Full Text Available OBJECTIVE: In the ANRS 139 TRIO trial, the use of 3 new active drugs (raltegravir, etravirine, and darunavir/ritonavir, resulted in a potent and sustained inhibition of viral replication in multidrug-resistant treatment-experienced patients. The aim of this virological sub-study of the ANRS 139 TRIO trial was to assess: (i the evolution of HIV-1 DNA over the first year; and (ii the association between baseline HIV-1 DNA and virological outcome. METHODS: Among the 103 HIV-1-infected patients included in the ANRS-139 TRIO trial, HIV-1 DNA specimens were available for 92, 84, 88, and 83 patients at Week (W0, W12, W24, and W48, respectively. Quantification of total HIV-1 DNA was performed by using the commercial kit "Generic HIV DNA Cell" (Biocentric, Bandol, France. RESULTS: Baseline median HIV-1 DNA of patients displaying virological success (n= 61, viral blip (n= 20, and virological failure (n = 11 were 2.34 log(10 copies/10(6 PBMC (IQR= 2.15-2.66, 2.42 (IQR = 2.12-2.48, and 2.68 (IQR= 2.46-2.83, respectively. Although not statistically significant, patients exhibiting virological success or viral blip had a tendency to display lower baseline HIV-1 DNA than patients experiencing virological failure (P = 0.06. Median decrease of HIV-1 DNA between baseline and W48 was -0.13 log(10 copies/10(6 PBMC (IQR = -0.34 to +0.10, mainly explained by the evolution from W0 to W4. No more changes were observed in the W4-W48 period. CONCLUSIONS: In highly-experienced multidrug-resistant patients, HIV-1 DNA slightly decreased during the first month and then remained stable during the first year of highly potent antiretroviral regimen. In this population, baseline HIV-1 DNA might help to better predict the virological response and to tailor clinical therapeutic management as more aggressive therapeutic choices in patients with higher baseline HIV-1 DNA.

  14. Effects of TiO2 and Co3O4 Nanoparticles on Circulating Angiogenic Cells

    Science.gov (United States)

    Spigoni, Valentina; Cito, Monia; Alinovi, Rossella; Pinelli, Silvana; Passeri, Giovanni; Zavaroni, Ivana; Goldoni, Matteo; Campanini, Marco; Aliatis, Irene; Mutti, Antonio

    2015-01-01

    Background and Aim Sparse evidence suggests a possible link between exposure to airborne nanoparticles (NPs) and cardiovascular (CV) risk, perhaps through mechanisms involving oxidative stress and inflammation. We assessed the effects of TiO2 and Co3O4 NPs in human circulating angiogenic cells (CACs), which take part in vascular endothelium repair/replacement. Methods CACs were isolated from healthy donors’ buffy coats after culturing lymphomonocytes on fibronectin-coated dishes in endothelial medium for 7 days. CACs were pre-incubated with increasing concentration of TiO2 and Co3O4 (from 1 to 100 μg/ml) to test the effects of NP – characterized by Transmission Electron Microscopy – on CAC viability, apoptosis (caspase 3/7 activation), function (fibronectin adhesion assay), oxidative stress and inflammatory cytokine gene expression. Results Neither oxidative stress nor cell death were associated with exposure to TiO2 NP (except at the highest concentration tested), which, however, induced a higher pro-inflammatory effect compared to Co3O4 NPs (p<0.01). Exposure to Co3O4 NPs significantly reduced cell viability (p<0.01) and increased caspase activity (p<0.01), lipid peroxidation end-products (p<0.05) and pro-inflammatory cytokine gene expression (p<0.05 or lower). Notably, CAC functional activity was impaired after exposure to both TiO2 (p<0.05 or lower) and Co3O4 (p<0.01) NPs. Conclusions In vitro exposure to TiO2 and Co3O4 NPs exerts detrimental effects on CAC viability and function, possibly mediated by accelerated apoptosis, increased oxidant stress (Co3O4 NPs only) and enhancement of inflammatory pathways (both TiO2 and Co3O4 NPs). Such adverse effects may be relevant for a potential role of exposure to TiO2 and Co3O4 NPs in enhancing CV risk in humans. PMID:25803285

  15. Investigation of miscibility of p(3hydroxybutyrate-co-3hydroxyhexanoate) and epoxidized natural rubber blends

    Energy Technology Data Exchange (ETDEWEB)

    Akram, Faridah; Chan, Chin Han; Natarajan, Valliyappan David [Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, 40450 Selangor Darul Ehsan (Malaysia)

    2015-08-28

    Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate [P(3HB-co-3HHx)] produced by C. necator PHB{sup −}4 harboring phaC{sub cs} from crude palm kernel oil with 21 mol% of 3-hydroxyhexanoate and epoxidized natural rubber with 25 mol% of epoxy content (ENR-25) were used to study the miscibility of the blends by attenuated total reflection-Fourier transform infrared (ATR-FTIR) and differential scanning calorimetry (DSC). The polymers used were purified and the blends were prepared by solution casting method. Nuclear magnetic resonance (NMR) spectra confirm the purity and molecular structures of P(3HB-co-3HHx) and ENR-25. FTIR spectra for different compositions of P(3HB-co-3HHx) and ENR-25 blends show absorbance change of the absorbance bands but with no significant shifting of the absorbance bands as the P(3HB-co-3HHx) content decreases, which shows that there is no intermolecular interaction between the parent polymer blends. On top of that, there are two T{sub g}s present for the blends and both remain constant for different compositions which corresponds to the T{sub g}s of the parent polymers. This indicates that the blends are immiscible.

  16. Investigation of miscibility of p(3hydroxybutyrate-co-3hydroxyhexanoate) and epoxidized natural rubber blends

    Science.gov (United States)

    Akram, Faridah; Chan, Chin Han; Natarajan, Valliyappan David

    2015-08-01

    Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate [P(3HB-co-3HHx)] produced by C. necator PHB-4 harboring phaCcs from crude palm kernel oil with 21 mol% of 3-hydroxyhexanoate and epoxidized natural rubber with 25 mol% of epoxy content (ENR-25) were used to study the miscibility of the blends by attenuated total reflection-Fourier transform infrared (ATR-FTIR) and differential scanning calorimetry (DSC). The polymers used were purified and the blends were prepared by solution casting method. Nuclear magnetic resonance (NMR) spectra confirm the purity and molecular structures of P(3HB-co-3HHx) and ENR-25. FTIR spectra for different compositions of P(3HB-co-3HHx) and ENR-25 blends show absorbance change of the absorbance bands but with no significant shifting of the absorbance bands as the P(3HB-co-3HHx) content decreases, which shows that there is no intermolecular interaction between the parent polymer blends. On top of that, there are two Tgs present for the blends and both remain constant for different compositions which corresponds to the Tgs of the parent polymers. This indicates that the blends are immiscible.

  17. Synthesis, characterization and ellipsometric study of ultrasonically sprayed Co3O4 films

    Science.gov (United States)

    Gençyılmaz, O.; Taşköprü, T.; Atay, F.; Akyüz, İ.

    2015-10-01

    In the present study, cobalt oxide (Co3O4) films were produced using ultrasonic spray pyrolysis technique onto the glass substrate at different temperatures (200-250-300-350 °C). The effect of substrate temperature on the structural, optical, surface and electrical properties of Co3O4 films was reported. Thickness, refractive index and extinction coefficient of the films were determined by spectroscopic ellipsometry, and X-ray diffraction analyses revealed that Co3O4 films were polycrystalline fcc structure and the substrate temperature significantly improved the crystal structure of Co3O4 films. The films deposited at 350 °C substrate temperature showed the best structural quality. Transmittance, absorbance and reflectance spectra were taken by means of UV-Vis spectrophotometer, and optical band gap values were calculated using optical method. Surface images and roughness values of the films were taken by atomic force microscopy to see the effect of deposition temperature on surface properties. The resistivity of the films slightly decreases with increase in the substrate temperature from 1.08 × 104 to 1.46 × 102 Ω cm. Finally, ultrasonic spray pyrolysis technique allowed production of Co3O4 films, which are alternative metal oxide film for technological applications, at low substrate temperature.

  18. Three-dimensional ordered mesoporous Co3O4 enhanced by Pd for oxygen evolution reaction

    Science.gov (United States)

    Qu, Qing; Zhang, Jian-Hua; Wang, Jing; Li, Qing-Yu; Xu, Chang-Wei; Lu, Xihong

    2017-01-01

    Considerable efforts have been devoted recently to design and fabrication of high performance and low cost electrocatalysts for oxygen evolution reaction (OER). However, catalytic activity of current electrocatalysts is usually restricted by high onset potential and limited active sites. Herein, we fabricated three-dimensional (3D) highly ordered mesoporous Pd-Co3O4 composite materials as excellent electrocatalysts for OER in alkaline solution with high activity and stability. Three-dimensional highly ordered mesoporous Co3O4 material was firstly synthesized using mesoporous silica KIT-6 as hard template. Then, Pd-Co3O4 nanomaterials were prepared by a simple reduction method. The as-prepared 3D mesoporous Pd-Co3O4 catalysts have ordered mesoporous structure with a high surface area of 81.0 m2 g‑1. Three-dimensional highly ordered mesoporous structure can facilitate diffusion and penetration of electrolyte and oxygen. Moreover, the catalysts can also keep catalyst particles in a well dispersed condition with more catalytic active sites. Electrochemical measurements reveal that the 3D mesoporous Pd-Co3O4 catalysts exhibit superior performance in alkaline solution with low onset potential (0.415 V vs. SCE) and excellent long-duration cycling stability.

  19. Charge ordering and exchange bias behaviors in Co3O4 porous nanoplatelets and nanorings

    Science.gov (United States)

    Debnath, J. C.; Wang, Jianli; Zeng, R.

    2017-01-01

    We present the synthesis of α-Co3O4 porous nanoplatelets and hexagonal nanorings using microwave-assisted hydrothermal and conventional chemical reaction methods. The x-ray diffraction (XRD) and refinement analyses indicate the α-Co3O4 crystal structure, and the x-ray photoelectron spectrum (XPS) indicates the high purity of the samples. The M-T (including 1/χ-T) curves indicate an antiferromagnetic transition at about 35 K in both kind of samples but the interesting finding was made that a charge-ordered (CO) state appears at 250 K for the nanoplatelets sample whereas it is inattentive for the nanorings. The antiferromagnetic transition temperature TN is lower than that of the bulk α-Co3O4 single crystal due to the nanosized structures. We observed quite significant exchange bias for nanorings. The exchange bias behavior of the α-Co3O4 hexagonal nanorings is consistent with an antiferromagnetic (AFM) Co3O4 core and spin-glass like shell.

  20. PVC/纳米CaCO3复合材料的制备与性能研究%Study on preparation and property of PVC/nano CaCO3 compound material

    Institute of Scientific and Technical Information of China (English)

    应建波; 钟明强; 徐立新

    2004-01-01

    根据非弹性体增韧改性理论,研究2种不同形态的纳米CaCO3粒子和1种普通碳酸钙粒子填充的PVC复合材料的性能.结果表明:加入一定量CaCO3可以提高PVC/CaCO3的力学性能,纳米级CaCO3填充的PVC复合材料性能优于普通轻质CaCO3体系;立方状纳米CaCO3填充的PVC复合材料的综合性能稍优于片状纳米CaCO3填充的PVC复合材料;随着CaCO3加入,PVC/CaCO3体系的塑化时间先增加后缩短,而且,纳米CaCO3填充的PVC复合材料的塑化时间比普通轻质CaCO3体系短.

  1. Formic Acid Modified Co3O4-CeO2 Catalysts for CO Oxidation

    Directory of Open Access Journals (Sweden)

    Ruishu Shang

    2016-03-01

    Full Text Available A formic acid modified catalyst, Co3O4-CeO2, was prepared via facile urea-hydrothermal method and applied in CO oxidation. The Co3O4-CeO2-0.5 catalyst, treated by formic acid at 0.5 mol/L, performed better in CO oxidation with T50 obtained at 69.5 °C and T100 obtained at 150 °C, respectively. The characterization results indicate that after treating with formic acid, there is a more porous structure within the Co3O4-CeO2 catalyst; meanwhile, despite of the slightly decreased content of Co, there are more adsorption sites exposed by acid treatment, as suggested by CO-TPD and H2-TPD, which explains the improvement of catalytic performance.

  2. Foaming of CRT panel glass powder with Na2CO3

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Smedskjær, Morten Mattrup

    composition in question. In this work, we foam panel glass cullet using sodium carbonate (Na2CO3) as a foaming agent, and study the foaming mechanism. When heat treating Na2CO3 powder with cullet powder, Na2CO3 reacts with the glass melt and is decomposed into Na2O and CO2. The released CO2 foams the glass......Recycling of cathode ray tube (CRT) glass remains a challenging task. The CRT glass consists of four glass types fused together: Funnel-, neck-, frit- and panel glass. The three former glasses contain toxic lead oxide, and therefore have a low recycling potential. The latter on the other hand...... is lead-free, but since barium and strontium oxide are present, panel glass is incompatible with most common recycling methods. However, foam glass production is a promising approach for the recycling of panel glass waste, since the process parameters can be changed according to the glass waste...

  3. Multidimensional Co3O4 nano sponge for the highly sensitive SERS applications

    Science.gov (United States)

    Zhao, Miao-miao; Liu, Wen-yao; Du, Jian-gong; Guo, Xu-dong; Wang, Lei; Xia, Mei-jing; Tang, Jun

    2017-01-01

    In this work, surface enhanced Raman spectroscopy (SERS) substrates with Ag nanoparticles (NPs) decorated Co3O4 nanowires (NWs) grafted on the three-dimensional (3D) network architecture of Ni foam (denoted as Ag-NP@Co3O4-NW/Ni-foam) arrays are manufactured. In the experiment, the hierarchical Ag-NP@Co3O4-NW/Ni-foam arrays exhibit strong SERS activity due to the higher density of the "hot spots" created from the large quantities of neighboring Ag NPs. Using this hierarchical 3D SERS substrates, the crystal violet (a banned drug of aquaculture) with concentration down to 10-14 mol/L can be detected, which shows potential application in SERS-based rapid trace-level detection of harmful food additives.

  4. AC Humidity Sensing Properties of Mesoporous K2CO3-SiO2 Composite Materials

    Directory of Open Access Journals (Sweden)

    Liang Guo

    2016-01-01

    Full Text Available The mesoporous silica SBA-15 and mesoporous K2CO3-SiO2 composite material were synthesized. Characterization of microstructure and morphology of materials indicated that the composite material had saved the porous framework of mesoporous silica SBA-15. Humidity sensing properties of different inverse proportion K2CO3-SiO2 composite material were studied and we found that the sample with 0.16 g/g K2CO3 exhibited excellent linearity in the wide humidity range. The complex impedance changed five orders of magnitude from 11% RH to 95% RH. The rapid response and recovery time were 10 s and 38 s, respectively. Finally a feasible ion transfer mechanism was brought forward to explain the sensing mechanism.

  5. Time-resolved laser fluorescence spectroscopy of UO2(CO3)3(4-).

    Science.gov (United States)

    Jung, E C; Cho, H-R; Baik, M H; Kim, H; Cha, W

    2015-11-21

    The objective of the present study is to examine the luminescence characteristics of UO2(CO3)3(4-) in detail using time-resolved laser fluorescence spectroscopy. The peak wavelengths and lifetime of UO2(CO3)3(4-) were determined at room temperature using the two excitation laser wavelengths of 266 and 448 nm. The peak wavelengths in the luminescence spectrum exhibited hypsochromic shifts compared with those of UO2(2+). The lifetime determined from several samples containing various uranium concentrations was 8.9 ± 0.8 ns. Explanations for the hindrance to the observation of the luminescence spectrum of UO2(CO3)3(4-) in previous investigations are discussed. The representative experimental parameters, which might interrupt the measurement of weak luminescence, are the insertion delay time of the detection device, the overlapped luminescence of the background materials and the primary inner filter effect in the sample solution.

  6. Photoelectron velocity-map imaging and theoretical studies of heteronuclear metal carbonyls MNi(CO)3- (M = Mg, Ca, Al)

    Science.gov (United States)

    Xie, Hua; Zou, Jinghan; Yuan, Qinqin; Fan, Hongjun; Tang, Zichao; Jiang, Ling

    2016-03-01

    The heteronuclear metal carbonyl anions MNi(CO)3- (M = Mg, Ca, Al) have been investigated using photoelectron velocity-map imaging spectroscopy. Electron affinities of neutral MNi(CO)3 (M = Mg, Ca, Al) are measured from the photoelectron spectra to be 1.064 ± 0.063, 1.050 ± 0.064, and 1.541 ± 0.040 eV, respectively. The C-O stretching mode in these three clusters is observed and the vibrational frequency is determined to be 2049, 2000, and 2041 cm-1 for MgNi(CO)3, CaNi(CO)3, and AlNi(CO)3, respectively. Density functional theory calculations are carried out to elucidate the geometric and electronic structures and to aid the experimental assignments. It has been found that three terminal carbonyls are preferentially bonded to the nickel atom in these heterobinuclear nickel carbonyls MNi(CO)3-1/0, resulting in the formation of the Ni(CO)3 motif. Ni remains the 18-electron configuration for MgNi(CO)3 and CaNi(CO)3 neutrals, but not for AlNi(CO)3. This is different from the homobinuclear nickel carbonyl Ni-Ni(CO)3 with the involvement of three bridging ligands. Present findings would be helpful for understanding CO adsorption on alloy surfaces.

  7. Electrodeposition of Mesoporous Co3O4 Nanosheets on Carbon Foam for High Performance Supercapacitors

    Directory of Open Access Journals (Sweden)

    Zhemi Xu

    2014-01-01

    Full Text Available Metal oxide nanosheets have promising potential applications in novel energy storage devices. In this work, Co3O4 nanosheets/carbon foam with excellent supercapacitor characteristics was successfully fabricated, without using metal substrates. The experimental results demonstrate that the electrochemical tests showed that the as-prepared Co3O4 nanosheets exhibited an ideal capacitive behavior with a maximum specific capacitance of 106 F/g in 1 M NaOH solution at a scan rate of 0.1 V s−1.

  8. Interdiffusion between Co3O4 coating and the oxide scale of Fe-22Cr alloy

    DEFF Research Database (Denmark)

    Hansson, Anette Nørgaard; Friehling, Peter B.; Linderoth, Søren;

    2002-01-01

    on Fe-Cr alloys. Coatings of Co3O4 were deposited on a Fe-22Cr alloy by plasma spraying and spray-painting. As-deposited samples were oxidised in air containing 1% H2O at 900C for various exposure time. During exposure the Fe-22Cr alloy forms an oxide scale, which reacts with the coating. The effects...... of inter-diffusion between the oxide scale and the Co3O4 coating were investigated with X-ray diffraction, scanning electron microscopy and energy-dispersive spectroscopy. The results obtained are discussed in relation to a calculated Cr-Co-oxide phase diagrams....

  9. Fabrication and properties of HDPE/CF/CaCO3/PE-g-MAH quaternary composites

    Science.gov (United States)

    Wang, X.-L.; Ming, H.; Yin, H.

    2015-07-01

    In this research, carbon fiber (CF) was taken as reinforcing filler, nano calcium carbonate (CaCO3) was taken as toughener, maleic anhydride grafted polyethylene (PE-g-MAH) was taken as compatibilizer for high density polyethylene (HDPE) modification. Through orthogonal test, the influence of different amount of ingredient CF, CaCO3 and PE-g-MAH on the mechanical properties of the HDPE composites was researched. The optimal composition of the quaternary composites with the good toughness and high strength was obtained.

  10. Facile synthesis of porous Co3O4 nanoplates for supercapacitor applications

    Indian Academy of Sciences (India)

    Tao Geng; Li Zhang; Hongyan Wang; Keying Zhang; Xia Zhou

    2015-09-01

    Porous tricobalt tetraoxide (Co3O4) nanoplates with large aspect ratio have been obtained by annealing Co(OH)2 precursor nanoplates synthesized by a facile reflux method without the need for any template or surfactant. After the heat treatment, the as-obtained phase-pure Co3O4 nanoplates with a wellretained structure were applied as the electrode material for supercapacitors, and the sample exhibits excellent performance with a high specific capacitance of 225 F g–1 after 2000 charge–discharge cycles at 2 A g–1, corresponding to a retention of 97% of the initial capacitance.

  11. 超细CaCO3的聚合物胶囊化研究%Study on encapsulation of ultrafine powders CaCO3 with polymer

    Institute of Scientific and Technical Information of China (English)

    丁建东; 罗付生; 杨光成; 付廷明; 宋洪昌

    2001-01-01

    先通过乳液聚合制备了粒径约为100nm带正电荷的聚苯乙烯PS纳球,再利用异相凝集,使正电性的PS吸附在带负电荷的超细碳酸钙(CaCO3)表面,后在高于PS玻璃化温度(Tg)下,进行热处理,形成胶囊化复合粒子.用Zeta电势、扫描电镜和粒径分布对复合前后的粒子进行了表征.

  12. Yb-doped Gd2O2CO3: Structure, microstructure, thermal and magnetic behaviour

    Science.gov (United States)

    Artini, Cristina; Locardi, Federico; Pani, Marcella; Nelli, Ilaria; Caglieris, Federico; Masini, Roberto; Plaisier, Jasper Rikkert; Costa, Giorgio Andrea

    2017-04-01

    Structural and microstructural features, as well as thermal and magnetic properties of Yb-doped Gd2O2CO3, were investigated with the aim to clarify the location and the oxidation state of Yb within the structure, and its role in driving the extent of the (Gd1-xYbx)2O2CO3 solid solution. Yb is found in the 3+ oxidation state and it enters the structure only at the rare earth atomic site; the solubility limit results to be located in the close vicinity of x=0.25, and thermal analyses reveal a linear decrease of the decomposition temperature with increasing the Yb amount, in agreement with literature data. The structural analysis allows to exclude long-range clusterization of Yb and Gd, since both rare earths randomly distribute over the 4f atomic position, but relying on the results of the microstructural analysis, the presence of compositional inhomogenities at the local scale cannot be excluded. Not all the structural forms are documented for the pure rare earth dioxycarbonates [1]; in particular, while form I exists for each lanthanide ion, form II is stable only for the largest ones (from La to Dy); moreover, even if II-Ho2O2CO3 (rHo3+ CN8=1.015 Å [6]) is not reported to be stable, the existence of II-Y2O2CO3 (rY3+ CN8=1.019 Å [6]) has been claimed [7]. Based on the described evidence, the stability of hexagonal Yb-doped Gd2O2CO3 is not expected along the whole compositional range. As a general remark, not all the rare earth mixed dioxycarbonates exist: (Ce, Gd)2O2CO3, for instance, could not be obtained at any composition [8]; moreover, all the structural forms can be observed only in some mixed systems, such as for example (Gd, Nd)2O2CO3, by varying temperature and tuning the composition [9]. Rare earth dioxycarbonates are studied mainly for their CO2 sensing properties [10,11], and for their emission when properly doped with a luminescent lanthanide ion [12-17]. Recently, a study of this research group [18] revealed in Gd2O2CO3:4% Yb a phenomenon of

  13. A novel approach in preparing polymer/nano-CaCO3 composites

    Institute of Scientific and Technical Information of China (English)

    Zhengying LIU; Runze YU; Mingbo YANG; Jianmin FENG; Wei YANG; Bo YIN

    2008-01-01

    An novel compounding process using nano-CaCO3 aqueous suspension for preparing polymer/ nano-CaCO3 composites with nanoparticles dispersed at the nanoscale is reported. The process is called the mild mixing method. In this method, the pre-dispersed nano-particle suspensions are blended with melting polymers in a weak shearing field using an extruder, followed by removing the water from the vent. The four typical poly-meric nanocomposites were prepared by mild mixing method. The dispersion of nano-CaCO3 in the matrix of the polymer at the nanoscale was confirmed by scanning electron microscopy (SEM). The molecular weights of polycarbonate (PC) and its nanocomposite showed that the degradation had not occurred during the mild mixing processing. The mechanical properties of the composite with 1.5 wt-% nano-CaCO3 improve slightly. It proved that this approach is suitable for the preparation of nano-composites based on both polar and non-polar polymers.

  14. Fabrication and Characterization of Nano-CaCO3/Polypropylene Foam Sheets

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    By applying the reinforcing and toughening effect of calcium carbonate (CaCO3) nanoparticles on polypropylene, foam sheets of good performance were successfully fabricated by extrusion. The equipment and conditions of the extrusion were explored. The mechanical properties of the produced foam sheets were tested. The effect of CaCO3 nano-particles on the mechanical properties and the cellular structure of the sheets was comprehensively studied. The experimental results show that the optimum content of CaCO3 nano-particles in the composite material was~4wt%. At this content, the nano-particles were well dispersed in the substrate, and the composite material had maximum tensile strength and impact strength. Surface treatment of the nano-particles only affected the impact strength of the composite material. CaCO3 micro-particles, on the other hand, showed little effect on the properties of the composite material when the micro-particles content was less than 5 wt%. At a content higher than 5wt%, the properties of the composite material significantly worsened.

  15. Preparation and electrochemical performance of nanosized Co3O4 via hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The hydrotalcite-type cobalt compounds were prepared through oxidation of Co(OH)2 gel using NH4OH as precipitating agent and H2O2 as oxidant. These hydrotalcite-type cobalt compounds were transformed into Co3O4 through hydrothermal decomposition with nanostructural deformation. The precursor and product were characterized by Fourier-transform infrared(FT-IR)spectrum, X-ray diffractometry(XRD) and transmission electron microscopy(TEM). The electrochemical performances of as-prepared nanosized Co3O4 as anode materials in lithium-ion batteries were tested by charge-discharge test in the voltage range of 0-3.0 V. The influence of morphology of Co3O4 particle on the capacity and cycling performance was studied. The results show that the shape and size of the final product can be controlled by altering cobalt sources. The irregular cubic Co3O4 with the average particle size of about 10 nm shows the best electrochemical performance. After 10 charge-discharge cycles, the specific charge capacity retains 555 mA·h/g.

  16. Exploring the Potential of (99m)Tc(CO)3-Labeled Triazolyl Peptides for Tumor Diagnosis.

    Science.gov (United States)

    Gaonkar, Raghuvir H; Ganguly, Soumya; Baishya, Rinku; Dewanjee, Saikat; Sinha, Samarendu; Gupta, Amit; Ganguly, Shantanu; Debnath, Mita C

    2016-04-01

    In recent years the authors have reported on (99m)Tc(CO)3-labeled peptides that serve as carriers for biomolecules or radiopharmaceuticals to the tumors. In continuation of that work they report the synthesis of a pentapeptide (Met-Phe-Phe-Gly-His; pep-1), a hexapeptide (Met-Phe-Phe-Asp-Gly-His; pep-2), and a tetrapeptide (Asp-Gly-Arg-His; pep-3) and the attachment of 3-amino-1,2,4-triazole to the β carboxylic function of the aspartic acid unit of pep-2 and pep-3. The pharmacophores were radiolabeled in high yields with [(99m)Tc(CO)3(H2O)3](+) metal aqua ion, characterized for their stability in serum and saline, as well as in His solution, and found to be substantially stable. B16F10 cell line binding studies showed favorable uptake and internalization. In vivo behavior of the radiolabeled triazolyl peptides was assessed in mice bearing induced tumor. The (99m)Tc(CO)3-triazolyl pep-3 demonstrated rapid urinary clearance and comparatively better tumor uptake. Imaging studies showed visualization of the tumor using (99m)Tc(CO)3-triazolyl pep-3, but due to high abdominal background, low delineation occurred. Based on the results further experiments will be carried out for targeting tumor with triazolyl peptides.

  17. Synthesis, characterization and self-assembly of Co3+ complexes appended with phenol and catechol groups

    Indian Academy of Sciences (India)

    Afsar Ali; Deepak Bansal; Rajeev Gupt

    2014-09-01

    This work presents the syntheses, characterization and hydrogen bonding based self-assembly of Co3+ complexes of pyridine-amide based bidentate ligands containing appended phenol and catechol groups. Placement of multiple hydrogen bond donors (phenolic OH and amidic NH groups) and acceptors (Oamide groups) in these molecules results in interesting self-assembled architectures.

  18. Electron-beam induced deposition and autocatalytic decomposition of Co(CO3NO

    Directory of Open Access Journals (Sweden)

    Florian Vollnhals

    2014-07-01

    Full Text Available The autocatalytic growth of arbitrarily shaped nanostructures fabricated by electron beam-induced deposition (EBID and electron beam-induced surface activation (EBISA is studied for two precursors: iron pentacarbonyl, Fe(CO5, and cobalt tricarbonyl nitrosyl, Co(CO3NO. Different deposits are prepared on silicon nitride membranes and silicon wafers under ultrahigh vacuum conditions, and are studied by scanning electron microscopy (SEM and scanning transmission X-ray microscopy (STXM, including near edge X-ray absorption fine structure (NEXAFS spectroscopy. It has previously been shown that Fe(CO5 decomposes autocatalytically on Fe seed layers (EBID and on certain electron beam-activated surfaces, yielding high purity, polycrystalline Fe nanostructures. In this contribution, we investigate the growth of structures from Co(CO3NO and compare it to results obtained from Fe(CO5. Co(CO3NO exhibits autocatalytic growth on Co-containing seed layers prepared by EBID using the same precursor. The growth yields granular, oxygen-, carbon- and nitrogen-containing deposits. In contrast to Fe(CO5 no decomposition on electron beam-activated surfaces is observed. In addition, we show that the autocatalytic growth of nanostructures from Co(CO3NO can also be initiated by an Fe seed layer, which presents a novel approach to the fabrication of layered nanostructures.

  19. Crystal structure and stability of Tl2CO3 at high pressures

    OpenAIRE

    Grzechnik, A.; Friese, K

    2010-01-01

    The crystal structure of dithallium carbonate, Tl2CO3 (C2/m, Z = 4), is stable to 5.82 GPa and does not undergo any phase transitions at lower pressures as reported previously. At higher pressures, the material undergoes a phase transition that destroys the single crystal.

  20. Co3O4–ZnO hierarchical nanostructures by electrospinning and hydrothermal methods

    DEFF Research Database (Denmark)

    Kanjwal, Muzafar Ahmed; Sheikh, Faheem A.; Barakat, Nasser A.M.

    2011-01-01

    A new hierarchical nanostructure that consists of cobalt oxide (Co3O4) and zinc oxide (ZnO) was produced by the electrospinning process followed by a hydrothermal technique. First, electrospinning of a colloidal solution that consisted of zinc nanoparticles, cobalt acetate tetrahydrate and poly...

  1. Preparation of Co3O4 Nanofibers via an Electrospinning Technique

    Institute of Scientific and Technical Information of China (English)

    Chang Lu SHAO; Hong Yu GUAN; Shang Bin WEN; Bin CHEN; Xing Hua YANG; Jian GONG; Yi Chun LIU

    2004-01-01

    Thin PVA/cobalt acetate composite fibers were prepared by using sol-gel processing and electrospinning technique.After calcination of the above precursor fibers, Co3O4 nanofibers with a diameter of 50-150 nm could be successfully obtained.The fibers were characterized by SEM, FT-IR,WAXD,respectively.

  2. Templated CaCO3 Crystallization by Submicrometer and Nanosized Fibers.

    Science.gov (United States)

    Neira-Carrillo, Andrónico; Gentsch, Rafael; Börner, Hans G; Acevedo, Diego Fernando; Barbero, Cesar Alfredo; Cölfen, Helmut

    2016-09-01

    Electrospun submicrometer-sized poly(ε-caprolactone) (PCL) meshes and nanosized multiwalled carbon nanotubes (MWCNTs) were used as a template for preparing porous and interconnected inorganic-organic hybrid materials composed of CaCO3. Herein, we describe the proportion and incorporation method of submicrometer-sized plasma-treated PCL meshes over areas >1 mm(2) with CaCO3 using three crystallization methods including the use of poly(acrylic acid) (PAA). We found that flexible and rigid acid-functionalized MWCNTs showed a clear capacity and effects to penetrate calcite particles. MWCNTs interacted differently with the individual growth planes of CaCO3, indicating that fibers can undergo changes depending on sulfonate or carboxylate groups, adopt different orientations in solution, and thereby elicit changes in CaCO3 morphology. In summary, the use of PCL and acidic MWCNT fibers as an additive for substrate templates and experimental crystallization provides a viable approach for studying various aspects of biomineralization, including the production of controlled particles, control of porosities, and defined morphologies at microscale and nanoscale levels.

  3. Benthic marine calcifiers coexist with CaCO3-undersaturated seawater worldwide

    Science.gov (United States)

    Lebrato, M.; Andersson, A. J.; Ries, J. B.; Aronson, R. B.; Lamare, M. D.; Koeve, W.; Oschlies, A.; Iglesias-Rodriguez, M. D.; Thatje, S.; Amsler, M.; Vos, S. C.; Jones, D. O. B.; Ruhl, H. A.; Gates, A. R.; McClintock, J. B.

    2016-07-01

    Ocean acidification and decreasing seawater saturation state with respect to calcium carbonate (CaCO3) minerals have raised concerns about the consequences to marine organisms that build CaCO3 structures. A large proportion of benthic marine calcifiers incorporate Mg2+ into their skeletons (Mg-calcite), which, in general, reduces mineral stability. The relative vulnerability of some marine calcifiers to ocean acidification appears linked to the relative solubility of their shell or skeletal mineralogy, although some organisms have sophisticated mechanisms for constructing and maintaining their CaCO3 structures causing deviation from this dependence. Nevertheless, few studies consider seawater saturation state with respect to the actual Mg-calcite mineralogy (ΩMg-x) of a species when evaluating the effect of ocean acidification on that species. Here, a global dataset of skeletal mole % MgCO3 of benthic calcifiers and in situ environmental conditions spanning a depth range of 0 m (subtidal/neritic) to 5600 m (abyssal) was assembled to calculate in situ ΩMg-x. This analysis shows that 24% of the studied benthic calcifiers currently experience seawater mineral undersaturation (ΩMg-x states when investigating the impact of CO2-induced ocean acidification on benthic marine calcification.

  4. Electron-beam induced deposition and autocatalytic decomposition of Co(CO)3NO

    Science.gov (United States)

    Vollnhals, Florian; Drost, Martin; Tu, Fan; Carrasco, Esther; Späth, Andreas; Fink, Rainer H; Steinrück, Hans-Peter

    2014-01-01

    Summary The autocatalytic growth of arbitrarily shaped nanostructures fabricated by electron beam-induced deposition (EBID) and electron beam-induced surface activation (EBISA) is studied for two precursors: iron pentacarbonyl, Fe(CO)5, and cobalt tricarbonyl nitrosyl, Co(CO)3NO. Different deposits are prepared on silicon nitride membranes and silicon wafers under ultrahigh vacuum conditions, and are studied by scanning electron microscopy (SEM) and scanning transmission X-ray microscopy (STXM), including near edge X-ray absorption fine structure (NEXAFS) spectroscopy. It has previously been shown that Fe(CO)5 decomposes autocatalytically on Fe seed layers (EBID) and on certain electron beam-activated surfaces, yielding high purity, polycrystalline Fe nanostructures. In this contribution, we investigate the growth of structures from Co(CO)3NO and compare it to results obtained from Fe(CO)5. Co(CO)3NO exhibits autocatalytic growth on Co-containing seed layers prepared by EBID using the same precursor. The growth yields granular, oxygen-, carbon- and nitrogen-containing deposits. In contrast to Fe(CO)5 no decomposition on electron beam-activated surfaces is observed. In addition, we show that the autocatalytic growth of nanostructures from Co(CO)3NO can also be initiated by an Fe seed layer, which presents a novel approach to the fabrication of layered nanostructures. PMID:25161851

  5. Electron-beam induced deposition and autocatalytic decomposition of Co(CO)3NO.

    Science.gov (United States)

    Vollnhals, Florian; Drost, Martin; Tu, Fan; Carrasco, Esther; Späth, Andreas; Fink, Rainer H; Steinrück, Hans-Peter; Marbach, Hubertus

    2014-01-01

    The autocatalytic growth of arbitrarily shaped nanostructures fabricated by electron beam-induced deposition (EBID) and electron beam-induced surface activation (EBISA) is studied for two precursors: iron pentacarbonyl, Fe(CO)5, and cobalt tricarbonyl nitrosyl, Co(CO)3NO. Different deposits are prepared on silicon nitride membranes and silicon wafers under ultrahigh vacuum conditions, and are studied by scanning electron microscopy (SEM) and scanning transmission X-ray microscopy (STXM), including near edge X-ray absorption fine structure (NEXAFS) spectroscopy. It has previously been shown that Fe(CO)5 decomposes autocatalytically on Fe seed layers (EBID) and on certain electron beam-activated surfaces, yielding high purity, polycrystalline Fe nanostructures. In this contribution, we investigate the growth of structures from Co(CO)3NO and compare it to results obtained from Fe(CO)5. Co(CO)3NO exhibits autocatalytic growth on Co-containing seed layers prepared by EBID using the same precursor. The growth yields granular, oxygen-, carbon- and nitrogen-containing deposits. In contrast to Fe(CO)5 no decomposition on electron beam-activated surfaces is observed. In addition, we show that the autocatalytic growth of nanostructures from Co(CO)3NO can also be initiated by an Fe seed layer, which presents a novel approach to the fabrication of layered nanostructures.

  6. Single crystalline Co3O4 nanocrystals exposed with different crystal planes for Li-O2 batteries.

    Science.gov (United States)

    Su, Dawei; Dou, Shixue; Wang, Guoxiu

    2014-08-29

    Single crystalline Co3O4 nanocrystals exposed with different crystal planes were synthesised, including cubic Co3O4 nanocrystals enclosed by {100} crystal planes, pseudo octahedral Co3O4 enclosed by {100} and {110} crystal planes, Co3O4 nanosheets exposed by {110} crystal planes, hexagonal Co3O4 nanoplatelets exposed with {111} crystal planes, and Co3O4 nanolaminar exposed with {112} crystal planes. Well single crystalline features of these Co3O4 nanocrystals were confirmed by FESEM and HRTEM analyses. The electrochemical performance for Li-O2 batteries shows that Co3O4 nanocrystals can significantly reduce the discharge-charge over-potential via the effect on the oxygen evolution reaction (OER). From the comparison on their catalytic performances, we found that the essential factor to promote the oxygen evolution reactions is the surface crystal planes of Co3O4 nanocrystals, namely, crystal planes-dependent process. The correlation between different Co3O4 crystal planes and their effect on reducing charge-discharge over-potential was established: {100} < {110} < {112} < {111}.

  7. Highly acid-durable carbon coated Co3O4 nanoarrays as efficient oxygen evolution electrocatalysts

    KAUST Repository

    Yang, Xiulin

    2016-04-21

    Most oxygen evolution reaction (OER) electrocatalysts are not stable in corrosive acids. Even the expensive RuO2 or IrO2, the most acid-resistant oxides, can be dissolved at an oxidative potential. Herein, we realize that the failures of OER catalysts are mostly caused by the weak interface between catalysts and the substrates. Hence, the study of the interface structure between catalysts and substrates is critical. In this work, we observe that the cheap OER catalysts Co3O4 can be more durable than the state-of-the-art RuO2 if the interface quality is good enough. The Co3O4 nanosheets deposited on carbon paper (Co3O4/CP) is prepared by electroplating of Co-species and followed by a two-step calcination process. The 1st step occurs in vacuum in order to maintain the surface integrity of the carbon paper and converts Co-species to Co(II)O. The 2nd step is a calcination in ambient conditions which enables the complete transformation of Co(II)O to Co3O4 without degrading the mechanical strength of the Co3O4-CP interface. Equally important, an in situ formation of a layer of amorphous carbon on top of Co3O4 further enhances the OER catalyst stability. Therefore, these key advances make the Co3O4 catalyst highly active toward the OER in 0.5 M H2SO4 with a small overpotential (370 mV), to reach 10 mA/cm2. The observed long lifetime for 86.8 h at a constant current density of 100 mA/cm2, is among the best of the reported in literature so far, even longer than the state-of-art RuO2 on CP. Overall, our study provides a new insight and methodology for the construction of a high-performance and high stability OER electrocatalysts in corrosive acidic environments.

  8. Study of Filling of PVC/CPE Composite by Nano-CaCO3%纳米级CaCO3填充PVC/CPE复合材料研究

    Institute of Scientific and Technical Information of China (English)

    胡圣飞; 严海标; 王燕舞; 林志云

    2000-01-01

    探讨了纳米级CaCO3粒子增韧增强PVC/CPE基理,研究了纳米级CaCO3与轻质CaCO3用量对PVC/CPE体系力学性能的影响.结果表明:纳米级CaCO3用量为5%~12%时体系拉伸强度,冲击强度都有明显提高,起到了增韧、增强的双重效果.轻质CaCO3填充PVC/CPE体系基本未见增韧效果,同时,随着轻质CaCO3用量的增加,体系的拉伸强度和断裂伸长率明显降低.

  9. Studies on Electrochemical Deposition and Characterization of Co3o4 Films

    Directory of Open Access Journals (Sweden)

    P.N. Shelke

    2011-01-01

    Full Text Available The Co3O4 films are prepared using two steps method. Initially, the films are electrochemically deposited on stainless steel and copper substrates from the solution containing CoSO4 and H3BO3 at various molar concentrations (0.05, 0.09, 0.13, 0.17, 0.21, 0.25 and 0.28 M of CoCl2 in deposition bath. These as-deposited films are transformed into Co3O4 phase by heating them at 350 °C / 2 hr. These as-heated films are characterized by using X-ray diffraction, X-ray photoelectron spectroscopy, UV-Visible spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. From the characterization studies, the as-heated films are found to be containing single cubic spinel Co3O4 phase with high purity. The variation in molar concentration of CoCl2 in electrochemical deposition bath showed the profound effect on optical properties of Co3O4 films. The better optical properties, (i absorptance (α = 0.945, emittance (ε = 0.071 and (ii absorptance (α = 0.950, emittance (ε = 0.070 are obtained for the Co3O4 films prepared on stainless steel and copper substrates respectively at 0.28 M concentration of CoCl2 as compared to the data reported in literature. The strength and adhesion of as-heated films on both the substrates are found to be good for the molar concentrations of CoCl2 < 0.28 M.

  10. CaCO3, its reaction and carbonate rocks: terahertz spectroscopy investigation

    Science.gov (United States)

    Zhan, Honglei; Wu, Shixiang; Zhao, Kun; Bao, Rima; Xiao, Lizhi

    2016-10-01

    Carbonate-rich rocks cover a primary part of the earth’s petroleum geology reservoir. The study of carbonate has special significance and more effective study methods are now needed. In order to improve the availability of carbonate rock detection, terahertz (THz) spectroscopy was employed to investigate relevant materials in Na2CO3  +  CaCl2  =  CaCO3  +  2NaCl, which is often used to generate CaCO3. By comparing the materials composited with different ions, it can be revealed that Ca2+, \\text{CO}32- , Na+ and Cl- have respective absorption features at different frequencies. Furthermore, by utilizing a conservation equation it can be observed that the average refractive indices of Na2CO3 as well as CaCl2 equal those of CaCO3 and NaCl in the entire range. Combining the absorption and refractive effect of the materials in the reaction can comprehensively characterize the different substances and reveal the inner interaction during the reaction. THz spectra can deduce the process of molecule rearrangement in the chemical reaction of long-term rock evolution. Besides, the absorption features of the real carbonate rock collected from the nearest town of Sinan county, Guizhou province in Yunnan-Guizhou plateau validate the peaks’ central frequencies of ions and the principal components of carbonates, which can be in agreement with the SEM-EDS analysis. This research will supply a spectral tool to identify the particles in the rock and deduce an evolution of petroleum carbonate reservoir.

  11. CaCO3 CYCLES IN SALAWUSU RIVER BASIN SINCE 150KA B. P.

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper, with Milanggouwan stratigraphic section as a typical section of the Salawusu River Basin,explores the relation between CaCO3 content distribution and climate change since 150 ka B.P. and concludes that: 1) The low-high changes of CaCO3 content in the section has a remarkable corresponding relation with the sedimentary cycles of ancient aeolian sand and overlying fluviolacustrine facies or palaeosols. 2) CaCO3 distribution in aeolian sand is relatively meagre, ranging from 0. 8% -7.18%, or on an average 2. 50% but relatively enriches in the fluviolacustrine faceis and palaeosols, ranging from 2. 20% - 14. 9%, or on an average 5.74%. This implies that they have different climatic backgrounds. The former was the product of erosion, transport and deposition by wind under arid and cold climatic conditions, whereas the latter was related to its special low-lying geomorphic position between the Ordos Plateau and Loess Plateau and warm-humid climatic environment. When the climatic became warm and humid, fluviola custrine and swamp facies developed, soil-forming action strengthened, and low-lying catchment condition was favor able to CaCO3 accumulation. 3) The basic cause responsible for the multicycie of CaCO3 migration and accumulation in the Milanggouwan section may be the multiple alterations of winter and summer monsoons over the Mu Us Desert under the influences of climatic fluctuation of glacial and interglacial periods in the Northern Hemisphere since 150ka B. P..

  12. Effect of Co3O4 and Co3O4/CeO2 infiltration on the catalytic and electro-catalytic activity of LSM15/CGO10 porous cells stacks for oxidation of propene

    DEFF Research Database (Denmark)

    Ippolito, Davide; Kammer Hansen, Kent

    2015-01-01

    The objective of this work was to study the effect of Co3O4 and Co3O4/CeO2 infiltration on the propene oxidation catalytic activity of a La0.85Sr0.15MnO3/Ce0.9Gd0.1O1.95 electrochemical porous cell stack (11 layers, 5 single cells in series). The effect of the infiltration of Co3O4 and Co3O4/CeO2...... on the electrochemical properties of the porous cell stack was also investigated by electrochemical impedance spectroscopy (EIS). Co3O4 and Co3O4/CeO2 exhibited high catalytic activity for propene oxidation. The increase of propene oxidation rate with +4 V (0.8 V/cell) polarization reached 10% for the Co3O4 infiltrated...... reactor and 48% of efficiency at 300 °C. The Co3O4/CeO2 co-infiltration decreased the reactor polarization resistance, while Co3O4 infiltration had negligible effect on reactor electrochemical performance. The beneficial effect of CeO2 on the electrode activity was attributed to the increased...

  13. Hierarchical porous microspheres of the Co3O4@graphene with enhanced electrocatalytic performance for electrochemical biosensors.

    Science.gov (United States)

    Yang, MinHo; Jeong, Jae-Min; Lee, Kyoung G; Kim, Do Hyun; Lee, Seok Jae; Choi, Bong Gill

    2017-03-15

    The integration of organic and inorganic building blocks into hierarchical porous architectures makes potentially desirable electrocatalytic materials in many electrochemical applications due to their combination of attractive qualities of dissimilar components and well-constructed charge transfer pathways. Herein, we demonstrate the preparation of the hierarchical porous Co3O4@graphene (Co3O4@G) microspheres by one-step hydrothermal method to achieve high electrocatalytic performance for enzyme-free biosensor applications. The obtained Co3O4@G microspheres are consisted of the interconnected networks of Co3O4 and graphene sheets, and thus provide large accessible active sites through porous structure, while graphene sheets offer continuous electron pathways for efficient electrocatalytic reaction of Co3O4. These structural merits with synergy effect of Co3O4 and graphene lead to a high performance of enzyme-free detection for glucose: high sensitivity, good selectivity, and remarkable stability.

  14. Changes in CaCO3 Burial Trump the Biological Pump

    Science.gov (United States)

    Toggweiler, J.; Dunne, J. P.

    2008-12-01

    The dramatic increases in atmospheric CO2 at the ends of ice ages are usually attributed to a one-two punch coming from the ocean. First, a weakened biological pump vents organically cycled CO2 from the deep ocean via changes in the ventilation of the deep ocean around Antarctica. The initial CO2 increase is then augmented by an enhancement of CaCO3 burial due to a process called CaCO3 compensation (after Broecker, W. S and T.-H. Peng, Global Biogeochem. Cycles, 1, 15-29, 1987). Here, we argue that the importance of the biological pump has been exaggerated. The main effect comes from circulation-induced changes in the burial of CaCO3. As shown in a recent paper by Andreas Schmittner and co-authors (Schmittner, A., E. Brook and J. Ahn, Impact of the ocean's overturning circulation on atmospheric CO2, in Ocean Circulation: Mechanisms and Impacts, Geophys. Monogr. 173, A. Schmittner, J. Chiang, and S. Hemming, eds., pp. 209-246, AGU, 2007) changes in the ventilation of the deep ocean around Antarctica gave rise to 20-30 ppm increases in atmospheric CO2 every 5,000-7,000 years during isotope stages 3 and 4 (30,000 to 70,000 years ago). None of these venting events gave rise to a compensation response. Meanwhile, Jaccard et al. (Science, 308, 1003-1006, 2005) show that all the big CO2 increases during terminations through stage 11 were accompanied by huge increases in CaCO3 burial. This suggests that the enhanced burial of CaCO3 is obligatory rather than compensatory with respect to the dramatic CO2 increases. Broecker and Peng's compensation idea is based on an assumption that the rain of CaCO3 to the sea floor is the same everywhere. More specifically, it assumes that there is no spatial correlation between the production of CaCO3 at the surface and the burial on the sea floor. We find instead that the production and burial of CaCO3 tend to be co-located in regional "hot spots" and that burial in the hot spots balances the input of Ca++ and HCO3- ions in rivers. The

  15. INTERFACIAL ADHESION AND MECHANICAL PROPERTIES OF PMMA-COATED CaCO3 NANOPARTICLE-REINFORCED PVC COMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Xuehua Chen; Chunzhong Li; Shoufang Xu; Ling Zhang; Wei Shao; H. L. Du

    2006-01-01

    Polymethyl methacrylate (PMMA)-coated nano-CaCO3 particles were prepared by in-situ emulsion polymerization. The mechanical properties of nano-CaCO3 particles-reinforced PVC were investigated using an AG-2000A universal testing machine and an XJU-2.75 izod impact tester; interfacial adhesion between CaCO3 nanoparticles and PVC matrix by SEM, and structure of PMMA coated on the surface of CaCO3 by FTIR and 1H-NMR. The results indicate that the PMMA coated on the nano CaCO3 particles consists mainly of syndiotactic structure, and their three tacticity contents were rr 52.8%, mm 7.3% and mr 39.9%, respectively. The interfacial adhesion between CaCO3 nanoparticles and PVC matrix was significantly improved when the CaCO3 nanoparticles were coated with PMMA, which led to increased Young's moduli and tensile strengths of the PMMA-coated CaCO3/PVC composites. The izod impact strengths of the composites were strongly affected by the PMMA coating thickness and increased significantly with increasing the volume fraction of CaCO3 filler in the composites.

  16. Synthesis and Crystal Structure of Borate Oxide Co3BO5

    Institute of Scientific and Technical Information of China (English)

    张浩; 程文旦; 黄子祥

    2001-01-01

    A mix-charge cation solid-state borate oxide Co3BO5 has beensynthesized and its structure has been determined by single-crystal X-ray methods. It crystallizes in the orthorhombic~space group Pbam with cell parameters a=9.2963(2), b=11.948(2), c=2.9737(6) Å, V=330.30(12)Å3, Z=4, Mr=267.60, F(000)=504, μ=14.733, Dcalcd=5.381g/cm3. The structure was determined from 853 unique reflections and refined to the final residuals R=0.0633 and wR=0.1457. It has two kinds of Co cations, Co2+ and Co3+. It is composed of highly distorted [CoO4] squares and triangular [BO3] groups that are connected to form infinite two-dimensional layers.

  17. Magnetic Properties of Nd8Fe83Co3B6 Nanocomposite Magnets

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The influence of quenching technology, annealing temperature and time on the structures and magnetic properties of Nd8Fe83Co3B6 nanocomposite magnets was investigated. The results show that the α-Fe/Nd2Fe14B nanocomposite magnet containing a small amount of B is difficult to form amorphous state. The magnetic properties of 26 m/s quenched Nd8Fe83Co3B6 powders annealed at 640℃×480 s reach iHc=513 kA/m, Br=1.05 T and (BH)max=92.0 kJ/m3. The grain size is Dα-Fe=21.5 nm and DNd2Fe14B=30.2 nm.

  18. Sonochemical fabrication of Ag2CO3 nanomaterial and influencing factors on photocatalytic properties

    Science.gov (United States)

    Zhou, Li; Liang, Liuying; Talifu, Dilinuer; Abulizi, Abulikemu

    2017-01-01

    Visible-light-active Ag2CO3 nanoparticles were synthesized by a simple sonochemical method (ambient temperature for only 1 h). The effects of ultrasound pulse mode, ultrasound time and pH value on the photodegradation properties of Ag2CO3 were investigated. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDS), UV-vis diffuse reflectance spectroscopy (DRS) and nitrogen adsorption–desorption techniques. The photocatalytic activity was evaluated by degrading methylene blue (MB) under visible light irradiation (λ>420nm). According to obtained results, it was found that MB degradation (about 99.4% after 20 min of irradiation) was higher compare to conventional stirring method, which might be due to the higher specific surface areas and active sites. The method described here can be used to improve the efficiency of visible-light sources and develop an ecologically friendly, practical wastewater treatment for pollutants.

  19. The magnetoelectirc effect on the novel multiferroic Co3TeO6

    Science.gov (United States)

    Chou, C. C.; Mukherjee, S.; Zhang, J. H.; Her, J. L.; Berger, H.; Yang, H. D.

    2012-02-01

    The magnetic, thermal, and dielectric measurements were performed on a single crystal sample Co3TeO6. Two anomalies are observed at T1 ˜ 26 K and T2 ˜ 18 K in magnetic susceptibility and specific heat measurements. Dielectric constant data show a step anomaly at 18 K, which does not display frequency-dependent behavior but a magnetoelectric effect. Furthermore, the values of the magnetoelectric coupling constantγ were calculated, which are 0.0268 and 0.0239 at 7 K and 13 K, respectively. The temperature-dependent X-ray diffraction suggests that the lattice parameters slightly deviate form linear trend as temperature down to 26 K, and then shows an anomalous variation around 18 K, where a structural distortion probably appears. All phenomena of our results indicate that Co3TeO6 is one member of multiferroic materials

  20. Preparation, Morphology Transformation and Magnetic Behavior of Co3O4 Nano-Leaves

    Institute of Scientific and Technical Information of China (English)

    MENG Ling-Rong; CHEN Wei-Meng; CHEN Chin-Ping; ZHOU He-Ping; PENG Qing

    2010-01-01

    @@ A series of cubic phase Co3O4 nano-leaves were prepared via a combined approach of solution reaction and calcination.According to x-ray diffraction and electron microscopy,we find that the Co3O4 grain size increases with calcination temperature.This can induce many gaps in the products.M-T and M-H magnetization measurements reveal the typical antiferromagnetic behavior of nano-leaves.The effective moments of the samples prepared at 300,400 and 500℃ are 5.6,5.8 and 5.7μB per formula unit(FU),respectively,larger than the bulk value of 4.14μB/FU.

  1. The structural, electronic, elastic and dynamic properties of Co3W in the L12 phase

    Science.gov (United States)

    Arikan, Nihat

    2017-02-01

    A theoretical study is presented for the structural, electronic, elastic and phonon properties of Co3W compounds in L12 phase in the framework of density functional theory. The calculations are carried out within the PBE-GGA for the exchange correlation potential. The electronic structure and particle density of states (DOS) show that Co3W compound is metallic with sturdy hybridization near the Fermi level. The phonon dispersion curves, and the projected density of states been investigated for the first time with an ab initio method using density functional perturbation theory (DFPT). Temperature variations of specific heat capacity in the range of 0-2000 K are obtained using the quasi-harmonic model.

  2. Intra-ring haptotropic rearrangements of Mn(CO3 in fluorenyl ligands

    Directory of Open Access Journals (Sweden)

    Souhila Laib

    2017-02-01

    Full Text Available Geometric parameters, and intra-ring haptotropic rearrangements π–π (intra-ring-HRs ŋ5⇌ŋ3 of the manganesetricarbonyl complexes (ŋ5-9-R-C13H8Mn(CO3, R = But and Ph in 18e zero-valence are carried out using density functional theory DFT at PBE/TZP level. The calculated activation barriers to ŋ5⇌ŋ3 intra-ring HR in (ŋ5-9-R-C13H8Mn(CO3, R = But and Ph are (28.5 and 69.5 kcal.mol−1 respectively. The compute of HOMA and FLU indexes indicates the reduction of aromaticity when going from free to coordinated complex. The energy decomposition analysis reveals the dominant ionic character in manganese–Cp bond in the presence of covalent contribution.

  3. Synthesis and characterization of cobalt oxide nanocomposite based on the Co3O4-zeolite Y

    Science.gov (United States)

    Davar, Fatemeh; Fereshteh, Zeinab; Shoja Razavi, Hadi; Razavi, Reza Shoja; Loghman-Estarki, Mohammad Reza

    2014-02-01

    The Co3O4 nanocomposite was synthesized by an ion-exchange of cobalt ions and Y zeolite in the presence of sodium hydroxide and calcination treatment. The products were characterized by X-ray diffraction (XRD), Raman analysis, scanning electron microscope (SEM), transmission electron microscope (TEM), BET, Energy-dispersive X-ray spectroscopy (EDX) and Fourier transform infrared (FTIR) spectroscopy. The sizes of the migrated Co3O4 particles out of Y zeolite super cage were in the range of 29 ± 5 nm. Finally, the magnetic property of as-obtained product was investigated in a vibrating sample magnetometer (VSM). This nanocomposite showed a paramagnetic behavior at room temperature.

  4. Electric Field-Controlled Crystallizing CaCO3 Nanostructures from Solution.

    Science.gov (United States)

    Qi, Jian Quan; Guo, Rui; Wang, Yu; Liu, Xuan Wen; Chan, Helen Lai Wah

    2016-12-01

    The role of electric field is investigated in determining the structure, morphology, and crystallographic characteristics of CaCO3 nanostructures crystallized from solution. It is found that the lattice structure and crystalline morphology of CaCO3 can be tailed by the electric field applied to the solution during its crystallization. The calcite structure with cubic-like morphology can be obtained generally without electric field, and the vaterite structure with the morphology of nanorod is formed under the high electric field. The vaterite nanorods can be piled up to the petaliform layers. Both the nanorod and the petaliform layer can have mesocrystal structures which are piled up by much fine units of the rods with the size of several nanometers. Beautiful rose-like nanoflowers can be self-arranged by the petaliform layers. These structures can have potential application as carrier for medicine to involve into metabolism of living cell.

  5. Preparation of nanocrystalline Co3O4 and its properties as supercapacitors

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Nanocrystallines Co3O4 with the particle diameter of 3 nm are prepared and tested as active electrode material for an electrochemical supercapacitor. The results of characterization indicate that the grain size of this material is very small; the specific surface area is very high (192 m2/g); the distributions of pore diameter are desirable and effective; furthermore, the agglomeration problem among small particles was solved to a certain extent. The electrochemical tests show that the electrode prepared with the Co3O4 exhibits distinct characteristic of capacitance and very high specific capacitance of 365-401 F/g. Additionally, the main attribute of capacitance, namely supercapacitance, was also testified.

  6. Foaming of waste cathode ray tube panel glass via CaCO3

    DEFF Research Database (Denmark)

    König, Jakob; Petersen, Rasmus Rosenlund; Yue, Yuanzheng

    of a TV. In general CRT consists of two types of glasses: barium/strontium containing glass (panel glass) and lead containing glass (funnel and panel glass). In this work we present the possibility to produce high quality foam glass from the recycled lead-free glass. We study the influence of foaming...... parameters on the characteristics of foam. CRT panel glass was crushed, milled and sieved below 63 m. CaCO3 was used as a foaming agent and was mixed with glass powders by means of a planetary ball mill. Preliminary results show that milling conditions and particle size have a major influence on the foaming...... process and resulting density of samples. We investigate the influence of foaming agent concentration on the foaming process, foam density, foam porosity and homogeneity. We demonstrate how milling and foaming conditions affect the foam properties for different amounts of CaCO3. A minimum in the density...

  7. Facet-dependent electrochemical properties of Co3O4 nanocrystals toward heavy metal ions

    Science.gov (United States)

    Yu, Xin-Yao; Meng, Qiang-Qiang; Luo, Tao; Jia, Yong; Sun, Bai; Li, Qun-Xiang; Liu, Jin-Huai; Huang, Xing-Jiu

    2013-01-01

    We revealed an interesting facet-dependent electrochemical behavior toward heavy metal ions (HMIs) based on their adsorption behaviors. The (111) facet of Co3O4 nanoplates has better electrochemical sensing performance than that of the (001) facet of Co3O4 nanocubes. Adsorption measurements and density-functional theory (DFT) calculations reveals that adsorption of HMIs is responsible for the difference of electrochemical properties. Our combined experimental and theoretical studies provide a solid hint to explain the mechanism of electrochemical detection of HMIs using nanoscale metal oxides. Furthermore, this study not only suggests a promising new strategy for designing high performance electrochemical sensing interface through the selective synthesis of nanoscale materials exposed with different well-defined facets, but also provides a deep understanding for a more sensitive and selective electroanalysis at nanomaterials modified electrodes. PMID:24097175

  8. SYNTHESIS, REACTIONS AND STRUCTURE OF CP'TC(CO)3 DERIVATIVES

    NARCIS (Netherlands)

    CASTRO, HHK; MEETSMA, A; TEUBEN, JH; VAALBURG, W; PANEK, K

    1991-01-01

    A novel procedure for a high yield synthesis of Tc2(CO)10 is reported. Cyclopentadienyl technetium carbonyl complexes of general formula Cp'Tc(CO)3, where Cp' = eta-5-C5H5, eta-5-C5Me5, or eta-5-C5(Me)4[(CH2)3NMe2], have been prepared by reaction of Tc(CO)5I with the appropriate lithium cyclopentadi

  9. Synthesis, reactions and structure of Cp´Tc(CO)3 derivatives

    NARCIS (Netherlands)

    Knight Castro, H.H.; Meetsma, A.; Teuben, J.H.; Vaalburg, W.; Panek, K.

    1991-01-01

    A novel procedure for a high yield synthesis of Tc2(CO)10 is reported. Cyclopentadienyl technetium carbonyl complexes of general formula Cp´Tc(CO)3, where Cp´ = η5-C5H5, η5-C5Me5, or η5-C5(Me)4[(CH2)3NMe2], have been prepared by reaction of Tc(CO)5I with the appropriate lithium cyclopentadienide in

  10. Poly (3-Hydroxybutyrate-co-3-Hydroxyhexanoate)/Collagen Hybrid Scaffolds for Tissue Engineering Applications

    OpenAIRE

    Lomas, Alex J.; Webb, William R.; Han, Jianfeng; Chen, Guo-Qiang; Sun, Xun,; Zhang, Zhirong; El Haj, Alicia J.; Nicholas R Forsyth

    2013-01-01

    The benefits associated with polyhydroxyalkanoates (PHA) in tissue engineering include high immunotolerance, low toxicity, and biodegradability. Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx), a molecule from the PHA family of biopolymers, shares these features. In this study, the applicability of human embryonic stem cells (hESCs), spontaneously differentiated hESCs (SDhESCs), and mesenchymal stem cells (hMSCs) in conjunction with PHBHHx and collagen as a biocompatible replacement st...

  11. Formation of Co3O4 Nanotubes and the Magnetic Behaviour at Low Temperature

    Institute of Scientific and Technical Information of China (English)

    LI Tao; YANG Shao-Guang; HUANG Li-Sheng; GU Ben-Xi; DU You-Wei

    2004-01-01

    @@ Tubular Co3O4 nanostructures were prepared from cobalt nanowires embedded in an anodic alumina template.The morphologies of nanowires / nanotubes were studied by transmission electron microscopy, and x-ray diffraction was used in the analysis of the nanostructures and phases. A possible formation mechanism of the process from nanowires to nanotubes is discussed. The vibrating sample magnetometer measurements show anomalous magnetic behaviour of the cobalt oxide nanotubes at low temperature.

  12. Influence of Modified Nanosized CaCO3 on the Properties of Pigment Coated Paper%改性纳米CaCO3对涂布纸性能的影响

    Institute of Scientific and Technical Information of China (English)

    唐艳军; 李友明; 薛国新

    2008-01-01

    研究了纳米CaCO3、偶联剂改性纳米CaCO3及脂肪酸改性纳米CaCO3对涂布纸物理性能的影响.结果表明,含纳米CaCO3的纸张涂层具有较高的印刷光泽度和表面强度.表面改性对纳米CaCO3在涂布纸巾的应用有重要影响.以偶联剂和脂肪酸改性纳米CaCO3替代普通CaCO3,涂布纸的平滑度、光泽度、及油墨吸收性都大大提高,尤其表面强度改善更为明显,表面抗水性增强,水滴接触角明显增大.随着改性纳米CaCO3用量在5%~20%范围内增加,涂布纸性能持续改善.

  13. CuO and Co3O4 Nanoparticles: Synthesis, Characterizations, and Raman Spectroscopy

    Directory of Open Access Journals (Sweden)

    M. Rashad

    2013-01-01

    Full Text Available Copper oxide and cobalt oxide (CuO, Co3O4 nanocrystals (NCs have been successfully prepared in a short time using microwave irradiation without any postannealing treatment. Both kinds of nanocrystals (NCs have been prepared using copper nitrate and cobalt nitrate as the starting materials and distilled water as the solvent. The resulted powders of nanocrystals (NCs were characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM, scanning electron microscopy (SEM, and atomic force microscopy (AFM measurements. The obtained results confirm the presence of the both of oxides nanopowders produced during chemical precipitation using microwave irradiation. A strong emission under UV excitation is obtained from the prepared CuO and Co3O4 nanoparticles. The results show that the nanoparticles have high dispersion and narrow size distribution. The line scans of atomic force microscopy (AFM images of the nanocrystals (NCs sprayed on GaAs substrates confirm the results of both X-ray diffraction and transmission electron microscopy. Furthermore, vibrational studies have been carried out using Raman spectroscopic technique. Specific Raman peaks have been observed in the CuO and Co3O4 nanostructures, and the full width at half maximum (FWHM of the peaks indicates a small particle size of the nanocrystals.

  14. Synthesis of nano-CaCO3 composite particles and their application

    Institute of Scientific and Technical Information of China (English)

    Wei Wu; Xueqin Zhang; Jianfeng Chen; Shuling Shen

    2008-01-01

    Nano-calcium carbonate composite particles were synthesized by the soapless emulsion polymerization technique of dou-ble monomers. The composite particles formation mechanism was investigated. The effects of composite particles on the mechanical properties of nano-CaCO3-ABS (acrylonitrile-butadiene-styrene copolymer) composite material were studied. It was validated that the composite particles are made up of the nano-calcium carbonate cores and the shells of alternating copolymers of butyl acrylate (BA) and styrene (St). The shells are chemically grafted and physically wrapped on the surface of nano-calcium carbonate particles.When the composite particles were filled in ABS matrix, the CaCO3 particles are homogeneously dispersed in the composite material as nanoscales. The impact strength of the composite material is obviously enhanced after idling appropriate amounts of composite particles. It can be concluded that the soapless emulsion polymerization of double monomers is an effective method for nano-CaCO3 surface treatment.

  15. Amine ligand-based hydrothermal synthesis of Co3O4 nanoparticles, characterization and magnetic study

    Science.gov (United States)

    Mansournia, Mohammadreza; Rakhshan, Narges

    2016-12-01

    Cobalt(II,III) oxid (Co3O4) nanostructures have been successfully synthesized using [Co(NH3)6]Cl3 and [Co(en)3]Cl3 (en: ethylenediamine) as the single precursors via hydrothermal method, and CoCl2·6H2O through a facile ammonia-assisted approach. Indeed, ammine and en ligands, as well as ammonia vapor, act as the sources of hydroxide ion in the preparation of Co3O4 nanoparticles. The structure of products was confirmed by X-ray diffraction (XRD) technique and Fourier-transform infrared (FT-IR) spectroscopy and their morphologies were examined by scanning electron microscopy (SEM). The optical study of the as-prepared Co3O4 nanostructures using UV-Vis diffused reflectance spectroscopy (DRS) exhibited their semiconducting property by revealing one optical band gap in 3.3 eV. Moreover, the vibrating sample magnetometry (VSM) measurements showed a weak ferromagnetic behavior that could be attributed to uncompensated surface spins and/or finite-size effects. Further, the effects of the nature of the precursor, its concentration, temperature and reaction time on the size and morphology of the samples were studied in detail.

  16. Production of CaCO3/hyperbranched polyglycidol hybrid films using spray-coating technique.

    Science.gov (United States)

    Malinova, Kalina; Gunesch, Manfred; Montero Pancera, Sabrina; Wengeler, Robert; Rieger, Bernhard; Volkmer, Dirk

    2012-05-15

    Biomineralizing organisms employ macromolecules and cellular processing strategies in order to produce highly complex composite materials such as nacre. Bionic approaches translating this knowledge into viable technical production schemes for a large-scale production of biomimetic hybrid materials have met with limited success so far. Investigations presented here thus focus on the production of CaCO(3)/polymer hybrid coatings that can be applied to huge surface areas via reactive spray-coating. Technical requirements for simplicity and cost efficiency include a straightforward one-pot synthesis of low molecular weight hyperbranched polyglycidols (polyethers of 2,3-epoxy-1-propanol) as a simple mimic of biological macromolecules. Polymers functionalized with phosphate monoester, sulfate or carboxylate groups provide a means of controlling CaCO(3) particle density and morphology in the final coatings. We employ reactive spray-coating techniques to generate CaCO(3)/hybrid coatings among which vaterite composites can be prepared in the presence of sulfate-containing hyperbranched polyglycidol. These coatings show high stability and remained unchanged for periods longer than 9 months. By employing carboxylate-based hyperbranched polyglycidol, it is possible to deposit vaterite-calcite composites, whereas phosphate-ester-based hyperbranched polyglycidol leads to calcite composites. Nanoindentation was used to study mechanical properties, showing that coatings thus obtained are slightly harder than pure calcite.

  17. Effect of SrCO3 addition on the dynamic compressive strength of ZTA

    Institute of Scientific and Technical Information of China (English)

    Ali Arab; Roslan Ahmad; Zainal Arifin Ahmad

    2016-01-01

    Ceramic parts usually experience dynamic load in armor applications. Therefore, studying the dynamic behaviors of ceramics is important. Limited data are available on the dynamic behaviors of ceramics;thus, it is helpful to predict the dynamic strength of ceramics on the basis of their mechanical properties. In this paper, the addition of SrCO3 into zirconia-toughened alumina (ZTA) was demonstrated to improve the fracture toughness of ZTA due to the formation of the SrAl12O19 (SA6) phase. The porosity of ZTA was found to be increased by the addition of SrCO3. These newly formed pores served as the nucleation sites of cracks under dynamic load;these cracks eventually coalesced to form damaged zones in the samples. Although the KIC values of the samples were improved, the dynamic strength was not en-hanced because of the increase in porosity;in fact, the dynamic strength of ZTA ceramics decreased with the addition of SrCO3.

  18. Microencapsulation with alginate/CaCO3: A strategy for improved phage therapy

    Science.gov (United States)

    Colom, Joan; Cano-Sarabia, Mary; Otero, Jennifer; Aríñez-Soriano, Javier; Cortés, Pilar; Maspoch, Daniel; Llagostera, Montserrat

    2017-01-01

    Bacteriophages are promising therapeutic agents that can be applied to different stages of the commercial food chain. In this sense, bacteriophages can be orally administered to farm animals to protect them against intestinal pathogens. However, the low pH of the stomach, the activities of bile and intestinal tract enzymes limit the efficacy of the phages. This study demonstrates the utility of an alginate/CaCO3 encapsulation method suitable for bacteriophages with different morphologies and to yield encapsulation efficacies of ~100%. For the first time, a cocktail of three alginate/CaCO3-encapsulated bacteriophages was administered as oral therapy to commercial broilers infected with Salmonella under farm-like conditions. Encapsulation protects the bacteriophages against their destruction by the gastric juice. Phage release from capsules incubated in simulated intestinal fluid was also demonstrated, whereas encapsulation ensured sufficient intestinal retention of the phages. Moreover, the small size of the capsules (125–150 μm) enables their use in oral therapy and other applications in phage therapy. This study evidenced that a cocktail of the three alginate/CaCO3-encapsulated bacteriophages had a greater and more durable efficacy than a cocktail of the corresponding non-encapsulated phages in as therapy in broilers against Salmonella, one of the most common foodborne pathogen. PMID:28120922

  19. Fabrication and Properties of Degradable PPC/ EVOH/ starch/ CaCO3 Composites

    Institute of Scientific and Technical Information of China (English)

    QIAO Junjuan; DU Fengguang; PANG Maizhi; XIAO Min; WANG Shuanjin; MENG Yuezhong

    2008-01-01

    Thermally stable and biodegradable composites from poly (propylene carbonate) (PPC), poly (ethylene-co-vinyl alcohol) (EVOH), starch and CaCO3, were fabricated by melt blending. Differential scanning calorimetry (DSC), differential thermal analysis/ thermal gravimetric analysis (DTA/TGA), tensile test and scanning electron microscope (SEM) were performed to investigate the miscibility, thermal behavior and tensile properties of the PPC/ EVOH/ Starch/ CaCO3 composites. DSC results indicate that the introduction of EVOH could improve the compatibility between PPC and starch to some extent because of the interfacial interaction between PPC and EVOH, leading to an increase in tensile strength. The tensile strength began to decrease when more starch was added due to the aggregation of starch particles. SEM examination showed the good interfacial bonding between the fillers and polymeric components. The incorporation of both EVOH and fillers can greatly increase the thermal stability of PPC matrix. The PPC/ EVOH/ Starch/ CaCO3 composites can be melt processed and can be used as a common biodegradable material for a wide application.

  20. Local Spin State Measurements in Critically Doped La0 . 83Sr0 . 17CO3

    Science.gov (United States)

    Gulec, Ahmet; Klie, Robert F.

    2014-03-01

    Strontium doped LaCO3 has fascinating magnetic phases which are believed to be directly related to Co spin states. Critically doped La0 . 83 Sr0 . 17 CO3 undergoes a simultaneous Insulator to Metal Transition (IMT) and ferromagnetic (FM) order transition. In this work, we will utilized atomic-resolution Z-contrast imaging, annular bright field (ABF) imaging and electron energy-loss spectroscopy in the aberration-corrected JEOL JEM-ARM200CF in combination with cooling experiments to examine the local magnetic and spin-state transitions in critically doped La0 . 83 Sr0 . 17 CO3 between 80 K and 300 K. Our energy-loss magnetic circular dichroism (EMCD) experiments confirm the non-localized increase in the dichromatic signal at low temperature, associated with a change in the co-ion spin state. On the other hand, by using he ABF imaging, a distortion of the CO6 octahedral and the changes in the Co-O bond lengths within the same unit cell are observed. NSF CAREER Award DMR-0846748

  1. Precipitation of ALn(CO3),xH2O and Dy2(CO3),xH2O compounds from aqueous solutions for A=Li,Na,K,Cs,NH4+ and =La,Nd,Eu,Dy

    Science.gov (United States)

    Philippini, Violaine; Vercouter, Thomas; Chaussé, Annie; Vitorge, Pierre

    2008-09-01

    Double carbonates of lanthanide ( Ln) and alkaline or ammonium ( A) ions, noted ALn(CO3)2,xH2O, were precipitated from concentrated A2CO3 aqueous solutions at room temperature and atmospheric pressure. Twelve hydrated compounds out of the twenty targeted ones have been obtained: Li(Nd or Eu)(CO3)2, NaLa(CO3)2, KNd(CO3)2,xH2O, Cs(La or Nd)(CO3)2, NH4(Nd, Eu or Dy)(CO3)2, Dy2(CO3)3 from concentrated A2CO3 solutions and Na(Nd, Eu or Dy)(CO3)2 from concentrated AHCO3 solutions. Although the trivalent lanthanide ions are often considered as analogs in solution, differences in their precipitation behaviour was observed, which is believed to have a kinetic origin in relation to the small differences in their ionic radii. The solid compounds were characterised by elemental analyses, thermogravimetry (TG), X-ray diffraction (XRD) and scanning electron microscope-energy dispersive spectroscopy (SEM-EDS). The powder diffraction patterns of nine solids were fitted using the tetragonal P4/mmm Laüe class: LiNd(CO3)2,xH2O: a=(12.16±0.02) A˚, c=(9.21±0.02) A˚, LiEu(CO3)2,3H2O: a=(12.201±0.007) A˚, c=(9.23±0.01) A˚, KNd(CO3)2,xH2O: a=(13.28±0.04) A˚, c=(10.00±0.04) A˚, CsLa(CO3)2,xH2O: a=(10.82±0.02) A˚, c=(8.18±0.02) A˚, CsNd(CO3)2,xH2O: a=(10.81±0.07) A˚, c=(8.16±0.07) A˚ for NaLn(CO3)2,xH2O: a=(11.10+1.75r) A˚ and c=(8.60+1.13r) A˚, where r is the ionic radius of for a coordination number of 8 ( r=1.16 A˚, r=1.12 A˚, r=1.07 A˚ and r=1.03 A˚). It is proposed that all the NaLn(CO3)2,xH2O compounds are of very similar structure, as evidenced by their XRD patterns and by the linear variations of the lattice parameters with r. The small differences in the lattice parameters can induce large modification of the precipitation pathways. Conversely, structural changes were evidenced within the A+ series for ANd(CO3)2,xH2O. Dy2(CO3)3,xH2O was also obtained as a by-product. Its lattice parameters are in good agreement with Eu2(CO3)3,3H2O ones.

  2. 改性纳米CaCO3/PVC复合材料的力学性能%Mechanical Properties of Modified Nano-CaCO3/PVC Composites

    Institute of Scientific and Technical Information of China (English)

    徐守芳

    2007-01-01

    采用钛酸酯偶联剂和PMMA 接枝方法改性纳米碳酸钙,并采用熔融共混法制备了改性纳米CaCO3增韧PVC( CaCO3/PVC)复合材料,研究了复合材料的力学性能.对比于未处理纳米CaCO3和钛酸酯偶联剂处理纳米CaCO3,PMMA接枝聚合改性纳米CaCO3与基体的相容性最好,增韧PVC复合材料的拉伸强度得到较大幅度提高.

  3. Structures and energetics of (MgCO3)n clusters (n ≤ 16).

    Science.gov (United States)

    Chen, Mingyang; Jackson, Virgil E; Felmy, Andrew R; Dixon, David A

    2015-04-09

    There is significant interest in the role of carbonate minerals for the storage of CO2 and the role of prenucleation clusters in their formation. Global minima for (MgCO3)n (n ≤ 16) structures were optimized using a tree growth-hybrid genetic algorithm in conjunction with MNDO/MNDO/d semiempirical molecular orbital calculations followed by density functional theory geometry optimizations with the B3LYP functional. The most stable isomers for (MgCO3)n (n < 5) are approximately 2-dimensional. Mg can be bonded to one or two O atoms of a CO3(2-), and the 1-O bonding scheme is more favored as the cluster becomes larger. The average C-Mg coordination number increases as the cluster size increases, and at n = 16, the average C-Mg coordination number was calculated to be 5.2. The normalized dissociation energy to form monomers increases as n increases. At n = 16, the normalized dissociation energy is calculated to be 116.2 kcal/mol, as compared to the bulk value of 153.9 kcal/mol. The adiabatic reaction energies for the recombination reactions of (MgO)n clusters and CO2 to form (MgCO3)n were calculated. The exothermicity of the normalized recombination energy ⟨RE⟩CO2 decreases as n increases and converged to the experimental bulk limit rapidly. The normalized recombination energy ⟨RE⟩CO2 was calculated to be -52.2 kcal/mol for the monomer and -30.7 kcal/mol for n = 16, as compared to the experimental value of -27.9 kcal/mol for the solid phase reaction. Infrared spectra for the lowest energy isomers were calculated, and absorption bands in the previous experimental infrared studies were assigned with our density functional theory predictions. The (13)C, (17)O, and (25) Mg NMR chemical shifts for the clusters were predicted. The results provide insights into the structural and energetic transitions from nanoclusters of (MgCO3)n to the bulk and the spectroscopic properties of clusters for their experimental identification.

  4. An alternative model for CaCO3 over-shooting during the PETM : Biological carbonate compensation

    NARCIS (Netherlands)

    Luo, Yiming; Boudreau, Bernard P.; Dickens, Gerald R.; Sluijs, Appy; Middelburg, Jack J.

    2016-01-01

    Decreased CaCO3 content of deep-sea sediments argues for rapid and massive acidification of the oceans during the Paleocene–Eocene Thermal Maximum (PETM, ∼56 Ma BP). In the course of the subsequent recovery from this acidification, sediment CaCO3 content came to exceed pre-PETM levels, known as over

  5. Exploring the intermediates of photochemical CO2 reduction: reaction of Re(dmb)(CO)3 COOH with CO2.

    Science.gov (United States)

    Agarwal, Jay; Sanders, Brian C; Fujita, Etsuko; Schaefer, Henry F; Harrop, Todd C; Muckerman, James T

    2012-07-11

    We have investigated the reaction of Re(dmb)(CO)(3)COOH with CO(2) using density functional theory, and propose a mechanism for the production of CO. This mechanism supports the role of Re(dmb)(CO)(3)COOH as a key intermediate in the formation of CO. Our new experimental work supports the proposed scheme.

  6. Effect of Na2CO3 as Foaming Agent on Dynamics and Structure of Foam Glass Melts

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Smedskjær, Morten Mattrup;

    2014-01-01

    We investigate the kinetics and dynamics of the reaction between Na2CO3 and the cathode ray tube panel glass powder at 923-1173 K. The reaction causes foaming of the glass melt. After the reaction, the Tg decreases with increasing Na2CO3 content and reaches a minimum value of Tg. However, this Tg...

  7. Microwave-assisted synthesis of spheroidal vaterite CaCO 3 in ethylene glycol-water mixed solvents without surfactants

    Science.gov (United States)

    Chen, Yinxia; Ji, Xianbing; Wang, Xiaobo

    2010-10-01

    Spheroidal vaterite CaCO 3 composed of irregular nanoparticals have been synthesized by a fast microwave-assisted method. The structures are fabricated by the reaction of Ca(CH 3COO) 2 with (NH 4) 2CO 3 at 90 °C in ethylene glycol-water mixed solvents without any surfactants. The diameters of the spheroidal vaterite CaCO 3 range from 1 to 2 μm, and the average size of the nanoparticals is about 70 nm. Bundle-shaped aragonite and rhombohedral calcite are also obtained by adjusting the experimental parameters. Our experiments show that the ratio of ethylene glycol to water, microwave power, reaction time, and two sources of ammonium ions and acetate anions are key parameters for the fabrication of spheroidal vaterite CaCO 3. A possible growth mechanism for the spheroidal structures has been proposed, which suggests that the spheroidal vaterite CaCO 3 is formed by an aggregation mechanism.

  8. Study on the Effect of CaCO 3 on Open-cell Foaming Performance of Polypropylene%成核剂CaCO3对聚丙烯开孔发泡性能影响的研究

    Institute of Scientific and Technical Information of China (English)

    曹贤武; 何丁; 伍巍; 黄益威; 周南桥

    2011-01-01

    将高熔体强度聚丙烯(HMSPP)、线型低密度聚乙烯(LLDPE)、成核剂CaCO3共混后在自制超临界CO2动态发泡模拟机上发泡制备了聚丙烯开孔泡沫材料,研究了CaCO3的粒径和含量对聚丙烯开扎发泡性能的影响.结果表明:2500目CaCO3在HMSPP/LLDPE共混体系中的分散效果比5 000目CaCO3的好.添加2 500目和5 000目CaCO3后,发泡样品的发泡倍率减小,泡孔密度增大,泡孔直径减小,泡孔形貌变得规则,泡孔直径分布变窄,泡孔均匀性增加.添加3%的2500目和5 000目CaCO3时发泡性能最好.在共混体系中添加成核剂CaCO3能够提高发泡样品的开孔性能.%PP open-cell foam was prepared from the blends of high,melt-strength polypropylene ( HM-SPP) , linear low-density polyethylene (LLDPE) and nucleating agent CaCO, on a self-designed dynamic foaming simulation device. The effect of particle size and content of CaCO 3 on PP open-cell foaming performance was investigated. The results showed that 2 500 mesh CaCO3 diffused better than 5 000 mesh CaCO3 in HMSPP/LLDPE blends. As CaCO3 was added, the expansion ratio decreased, cell density increased,' cell diameter decreased, cell shape became regular, distribution of cell diameter became narrow, cell became more uniform. The foaming performance of HMSPP/LLDPE blends with 3% 2 500 mesh or 5 000 mesh CaCO 3 was best. As CaCO3 was added, open-cell performance increased.

  9. Immunologic and Virologic Progression in HIV Controllers: The Role of Viral "Blips" and Immune Activation in the ANRS CO21 CODEX Study.

    Science.gov (United States)

    Noel, Nicolas; Lerolle, Nathalie; Lécuroux, Camille; Goujard, Cécile; Venet, Alain; Saez-Cirion, Asier; Avettand-Fenoël, Veronique; Meyer, Laurence; Boufassa, Faroudy; Lambotte, Olivier

    2015-01-01

    Some HIV controllers (HICs) experience CD4+T cell count loss and/or lose their ability to control HIV. In this study, we investigated the rate of immunologic and/or virologic progression (ImmP/VirP) and its determinants in the ANRS CO21/CODEX cohort. Immunologic progression was defined as a lasting fall in CD4+T cell count below 350/mm(3) or more than 200/mm(3) with a baseline count below 600/mm(3). Virologic progression was defined as a HIV viral load (VL) above 2000 copies/mL on two consecutive determinations. Clinical characteristics, immune activation, ultrasensitive HIV VL and total HIV DNA were analyzed. Disease progression was observed in 15 of the 217 patients followed up between 2009 and 2013 (ImmP, n = 10; VirP, n = 5). Progressors had higher ultrasensitive HIV RNA levels at inclusion (i.e. 1-2 years before progression) than non-progressors. ImmP had also lower CD4+T cell nadir and CD4+T cell count at inclusion, and VirP had higher HIV DNA levels in blood. T cell activation and IP10 levels at inclusion were significantly higher in ImmP than in non-progressors. In summary, the lasting loss of CD4+T cells, residual HIV replication and basal levels of immune activation appear to be major determinants of progression in HICs. These factors should be considered for adjusting their follow-up.

  10. Rheological Behavior of Nano-CaCO3 Paper Coatings%含有改性纳米CaCO3的纸张涂料的流变行为

    Institute of Scientific and Technical Information of China (English)

    唐艳军; 李友明; 宋晶; 刘明友; 陈亮

    2007-01-01

    以阳离子表面活性剂、偶联剂及脂肪酸为表面改性剂获得表面性能不同的3种纳米CaCO3改性产品.用透射电镜桨相关化学分析方法表征了改性纳米CaCO3的界面行为.将改性纳米CaCO3加入纸张涂料体系中,制得不同配方的纸张涂料,并对涂料的静态流动性能和动态黏弹性进行了研究.结果表明,与加入普通CaCO3的传统涂料相比,含纳米CaCO3的纸张涂料具有较高的表观黏度、动态弹性模量和黏性模量,相位角则较低.表面亲油疏水的纳米CaCO3能够很好地与胶乳、增稠剂等聚合物胶体结合,弹性模量较大;而表面亲水的纳米CaCO3所制得的纸张涂料动态黏弹性较小.

  11. 高流动性PP/POE/纳米CaCO3复合材料的研制%Development of High Flowability PP/POE/Nano-CaCO3 Composites

    Institute of Scientific and Technical Information of China (English)

    张芳; 夏茹; 王俊海; 张大余

    2003-01-01

    利用双螺杆挤出机,通过熔融共混工艺制备了聚丙烯(PP)/聚烯烃热塑性弹性体(POE)/纳米CaCO3复合材料.利用扫描电子显微镜(SEM)观察了不同体系的形态,结果显示:纳米CaCO3和POE在PP/POE/nano-CaCO3中互相促进分布及均化.冲击试验结果表明:PP/POE/nano-CaCO3体系的缺口冲击强度较PP/POE、PP/nano-CaCO3和纯PP分别提高了65%,107%和178%.熔体流动速率测试显示:纳米CaCO3在PP/POE/nano-CaCO3中具有提高体系流动性的作用.

  12. Synthesis and characterization of fac-Re(CO)3-aspartic-N-monoacetic acid, a structural analogue of a potential new renal tracer, fac-(99m)Tc(CO)3(ASMA).

    Science.gov (United States)

    Klenc, Jeffrey; Lipowska, Malgorzata; Taylor, Andrew T; Marzilli, Luigi G

    2012-09-01

    The reaction of an aminopolycarboxylate ligand, aspartic-N-monoacetic acid (ASMA), with [Re(CO)3(H2O)3](+) was examined. The tridentate coordination of ASMA to this Re(I) tricarbonyl precursor yielded fac-Re(CO)3(ASMA) as a mixture of diastereomers. The chemistry is analogous to that of the Tc(I) tricarbonyl complex, which yields fac-(99m)Tc(CO)3(ASMA) under similar conditions. The formation, structure, and isomerization of fac-Re(CO)3(ASMA) products were characterized by HPLC, (1)H NMR spectroscopy, and X-ray crystallography. The two major fac-Re(CO)3(ASMA) diastereomeric products each have a linear ONO coordination mode with two adjacent five-membered chelate rings, but they differ in the endo or exo orientation of the uncoordinated acetate group, in agreement with expectations based on previous studies. Conditions have been identified for the expedient isomerization of fac-Re(CO)3(ASMA) to a mixture consisting primarily of one major product. Because different isomeric species typically have different pharmacokinetic characteristics, these conditions may provide for the practical isolation of a single (99m)Tc(CO)3(ASMA) species, thus allowing the isolation of the isomer that has optimal imaging and pharmacokinetic characteristics. This information will aid in the design of future (99m)Tc radiopharmaceuticals.

  13. Structures and Properties of Nano-CaCO3 PVC Composites%纳米CaCO3粒子填充PVC复合材料的结构与性能的研究

    Institute of Scientific and Technical Information of China (English)

    耿涛; 张秀斌; 李峰

    2007-01-01

    研究纳米CaCO3/PVC复合材料的微观结构、力学性能及流变性能,SEM观察复合材料冲击缺口的断面微观形态和纳米CaCO3粒子在PVC中的分散情况.结果表明:在PVC共混体系中加入纳米CaCO3可明显提高材料的韧性.当CaCO3用量在10份左右时,纳米CaCO3/PVC复合材料的冲击强度达到最大值,是普通CaCO3/PVC复合材料冲击强度的2倍,且复合材料的拉伸强度也略有提高.在流变学研究方面,纳米CaCO3/PVC复合材料与普通CaCO3/PVC复合材料同是假塑性流体.

  14. PVC Toughened with PU/Nano-CaCO3 by Reaction Extrusion Technology%反应挤出PU/纳米CaCO3增强增韧PVC

    Institute of Scientific and Technical Information of China (English)

    王士财; 张晓东; 李志国

    2009-01-01

    在考察聚氯乙烯/聚氨酯/纳米碳酸钙(PVC/PU/nano-CaCO3)反应挤出工艺的基础上,结合PU的反应特点,将表面处理的nano-CaCO3利用超声辐照技术并经搅拌分散于L-MDI中,采用反应挤出一步法制备了PU/nano-CaCO3共同增强增韧的PVC复合材料,并时其力学性能进行了研究.结果表明:PU/nano-CaCO3的质量配比为4:1时,增韧效果最佳,PU和nano-CaCO3能协同增韧PVC,且nano-CaCO3具有增强作用,当PVC/PU/nano-CaCO3质量比为100:20:5时,材料的综合性能最优.冲击强度达到58.3 kJ/m3,拉伸强度为51.5 MPa,增强增韧PVC效果显著.

  15. Mechanical properties of polyurethane-nano-CaCO3/polyvinyl chloride composites%聚氨酯-纳米CaCO3/PVC复合材料力学性能

    Institute of Scientific and Technical Information of China (English)

    王仕财; 朱春凤

    2009-01-01

    在考察了聚氨酯-纳米碳酸钙/聚氯乙烯(PU-nano-CaCO3/PVC)反应挤出工艺的基础上,结合PU的反应特点,将经硬脂酸表面处理的nano-CaCO3利用超声辐照技术并经搅拌分散于液化4,4'-二苯基甲烷二异氰酸酯(L-MDI)中,采用反应挤出一步法工艺制备了PU-nano-CaCO3/PVC复合材料,并对其力学性能进行了研究.结果表明,PU与nano-CaCO3的质量配比为4:1时,对PVC的增韧效果最佳,PU与nano-CaCO3能协同增韧PVC,且nano-CaCO3具有补强作用.当PU/nano-CaCO3/PVC质量比为20:5:75时,材料的综合性能最优,冲击强度达到58.3 kJ/m2,拉伸强度为51.5 MPa.

  16. Study of Nano-CaCO3 Toughening and Reinforcing PVC%纳米 CaCO3增韧增强 PVC 的研究

    Institute of Scientific and Technical Information of China (English)

    李勇

    2015-01-01

    研究纳米CaCO3不同含量共混对PVC的增韧增强改性影响,结果表明纳米CaCO3用量为10%时PVC样品冲击强度和拉伸强度达到最大值,同时随着纳米CaCO3加入量的增加,断裂伸长率一直呈下降趋势。综合实验数据,加工性能良好的PVC中纳米CaCO3的加入量控制在5%~10%较为适宜。%The modification with different content nano-CaCO3 in order to toughen and reinforce PVC was studied.The results showed that when nano-CaCO3 concentration was 10%, the impact strength and tensile strength of PVC reached maximum value, but the breaking elongation decreased along.PVC with better processing property were producted when adding content of nano-CaCO3 was between 5%and 10%.

  17. Physical properties and electronic band structure of noncentrosymmetric Th7Co3 superconductor.

    Science.gov (United States)

    Sahakyan, M; Tran, V H

    2016-05-25

    The physical properties of the noncentrosymmetric superconductor Th7Co3 have been investigated by means of ac-magnetic susceptibility, magnetization, specific heat, electrical resistivity, magnetoresistance and Hall effect measurements. From these data it is established that Th7Co3 is a dirty type-II superconductor with [Formula: see text] K, [Formula: see text] and moderate electron-phonon coupling [Formula: see text]. Some evidences for anisotropic superconducting gap are found, including e.g. reduced specific heat jump ([Formula: see text]) at T c, diminished superconducting energy gap ([Formula: see text]) as compared to the BCS values, power law field dependence of the Sommerfeld coefficient at 0.4 K ([Formula: see text]), and a concave curvature of the [Formula: see text] line. The magnitudes of the thermodynamic critical field and the energy gap are consistent with mean-squared anisotropy parameter [Formula: see text]. The electronic specific heat in the superconducting state is reasonably fitted to an oblate spheroidal gap model. Calculations of scalar relativistic and fully relativistic electronic band structures reveal considerable differences in the degenerate structure, resulting from asymmetric spin-orbit coupling (ASOC). A large splitting energy of spin-up spin-down bands at the Fermi level E F, [Formula: see text] meV is observed and a sizeable ratio [Formula: see text] could classify the studied compound into the class of noncentrosymmetric superconductors with strong ASOC. The noncentrosymmetry of the crystal structure and the atomic relativistic effects are both responsible for an importance of ASOC in Th7Co3. The calculated results for the density of states show a Van Hove singularity just below E F and dominant role of the 6d electrons of Th to the superconductivity.

  18. Biomineralization of strontianite(SrCO3) by aerobic microorganisms enriched from rhodoliths

    Science.gov (United States)

    Kang, S.; Roh, Y.

    2012-12-01

    The transport and fate of trace metals and radionuclides in natural environments are controlled by physical, chemical, and microbiological processes. Especially, microbially induced precipitation of carbonates has drawn much attention in recent decades because of its numerous implications such as atmospheric CO2 fixation through mineral carbonation and solid phase capture of inorganic contaminants. The objectives of this study were to investigate the potential for microbially induced precipitation of strontianite (SrCO3) using microorganisms enriched from rhodoliths and to identify mineralogical characteristics of the precipitates of strontianite. Carbonate forming microorganisms were enriched from rhodoliths, which were sampled at Seogwang-ri coast in the western part of Wu Island, Jeju-do, Korea. Microorganisms enriched from rhodoliths were aerobically cultured at 25Ć in D-1 media containing 30 mM Sr-acetate, and the microorganisms were analyzed by 16S rRNA gene DGGE analysis to confirm microbial diversity. Mineralogical characteristics of the carbonate minerals precipitated by the enriched microorganisms were determined by XRD, TEM-EDS, and SEM-EDS analyses. A 16S rRNA sequence analysis showed the enriched microorganisms contained carbonate forming microorganisms such as Proteus mirailis. The enriched microorganisms precipitated carbonate minerals using D-1 media containing 30 mM Sr-acetate and mineralogy of the precipitate was strontianite (SrCO3). SEM/TEM-EDS analyses showed that the strontianite formed by the microorganisms had a spherical shape and consisted of mainly Sr, O and C. TEM-EDS analyses showed that the strontianite formed by the microorganisms had a rhombohedron shape and consisted of mainly Sr, O and C. These results indicate that the microorganisms induce precipitation of strontianite (SrCO3) on the cell walls and EPS via the accumulation of Sr ions on the cells. Therefore, microbial precipitation of carbonate minerals may play one of important

  19. Structure and energetics in dissociative electron attachment to HFeCo3(CO)12*

    Science.gov (United States)

    P, Ragesh Kumar T.; Barth, Sven; Bjornsson, Ragnar; Ingólfsson, Oddur

    2016-08-01

    Here we report structural parameters on the heteronuclear transition metal complex HFeCo3(CO)12 and its anion formed upon electron attachment, as well as the thermochemical thresholds for sequential CO loss and the loss of the apical group (as Fe(CO)-3 and Fe(CO)-4). Geometrical parameters from single crystal X-ray diffraction are compared with calculated values from density functional theory calculations, for the neutral and anionic ground state of this transition metal cluster. Further, experimental appearance energies for sequential CO loss and the formation of Fe(CO)-3 and Fe(CO)-4 are compared to the respective calculated threshold values. Geometry optimizations were performed at the BP86/def2-TZVP level of theory while the threshold energies were calculated at the PBE0/ma-def2-TZVP level of theory. The SOMO of the anion is found to have a clear Fe-Co anti-bonding character resulting in elongation of the Fe-Co bonds and the transformation of one of the terminal Co-CO groups to a bridging Co-CO-Fe group upon electron attachment. The thermochemical threshold PBE0 calculations are concordant with the observed appearance energies and structural parameters from single crystal X-ray diffraction for the neutral molecule are well reproduced at the BP86/def2-TZVP level of theory. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.Supplementary material in the form of one pdf file available from the Journal web page at http://dx.doi.org/10.1140/epjd/e2016-70164-y

  20. Co3O4纳米立方体的可控合成及其CO氧化反应性能%Morphology-Controlled Synthesis of Co3O4 Nanocubes and Their Catalytic Performance in CO Oxidation

    Institute of Scientific and Technical Information of China (English)

    吕永阁; 李勇; 塔娜; 申文杰

    2014-01-01

    Co3O4 nanocubes that were exclusively terminated with{100}facets of edge size 10 nm were solvothermal y fabricated in a mixed solution of ethanol and triethylamine. Analyses of the structural evolution of the intermediates at different intervals during the synthesis, together with an examination of the influences of the cobalt precursor and solvent on the product structure, showed that the formation of Co3O4 nanocubes fol owed a dissolution-recrystal ization mechanism. After calcination at 200 ° C, the as-synthesized Co3O4 material retained a cubic morphology with the same edge size, but calcination at 400 ° C resulted in the formation of spherical Co3O4 particles of diameter about 13 nm. The Co3O4 nanocubes exhibited inferior activity in room-temperature CO oxidation compared with Co3O4 nanoparticles ({111}facets), primarily as a result of the exposure of the less-reactive {100} facets, demonstrating the morphology effect of Co3O4 nanomaterials.%在乙醇和三乙胺的混合溶液中,采用溶剂热法制备了尺寸为10 nm的Co3O4立方体。考察了钴盐前驱体和溶解氧对Co3O4纳米立方体结构的影响规律,通过对合成过程中不同阶段产物的结构分析和表征,提出了Co3O4纳米立方体的形成机制是溶解再结晶的过程。将所制备的Co3O4纳米立方体在200°C焙烧处理后,尺寸和形貌均可保持稳定,但400°C焙烧后,变为球形纳米粒子。这种主要暴露{100}晶面的Co3O4纳米立方体催化CO氧化反应的活性低于纳米粒子({111}晶面),验证了四氧化三钴纳米材料在CO氧化反应中的晶面效应。

  1. Preparation and Characterization of Nano CaCO3 Modified with Silica Sol and Study of Its Property%改性纳米CaCO3复合粒子的制备、表征及性能

    Institute of Scientific and Technical Information of China (English)

    杨冬亚; 邱凤仙; 朱复红; 吴冬梅; 张勤勤

    2008-01-01

    采用含有纳米硅溶胶的纳米碳酸钙悬浮液在超声波处理及加热条件下,硅溶胶发生缩合反应从而沉积在纳米碳酸钙粒子表面的溶胶-凝胶沉淀法,制备出性能稳定的纳米碳酸钙/二氧化硅复合粒子.通过红外光谱(FTIR)、TEM分析、zeta电位测定以及TGA分析,表征了硅溶胶与纳米CaCO3粒子之间的杂化作用,研究了改性纳米CaCO3复合粒子水分散液的稳定性和粒径、两种纳米粒子之间的包覆作用、杂化作用以及改性后纳米CaCO3复合粒子的热稳定性.同时研究发现,改性后的无机纳米CaCO3复合粒子在聚氨酯脲水分散液中具有很好的分散性.%The stable nano silica sol modified llano CaCO3 aqueous dispersion was prepared by means of sol-gel method with the treatment of ultrasonic.The FTIR,TEM,Zeta potential and TGA were used to analyze the hybrid effect of nano silica sol and nano CaCO3.The stability and particle size of the modified nano CaCO3 aqueous dispersion were studied,the covering effect between the two nano particles and the heat resistance of the modified nano CaCO3 were measured.Meanwhile,the polyurethanurea(PUU)/modified nano CaCO3 hybrid aqueous dispersion with solid content of 30%was prepared by in-situ dispersing PUU with the modified nano CaCO3 aqueous dispersion.The result showed that the modified nano CaCO3 possessed good dispersity in the hybrid PUU dispersion and the mechanical properties of the PUU films were enhanced appreciably with the hybrid of the modified nano CaCO3.

  2. 纳米CaCO3在环保型聚氯乙烯管材中的应用%The application of nano-CaCO3 to the environment-friendly PVC pipes

    Institute of Scientific and Technical Information of China (English)

    张友新

    2006-01-01

    介绍了纳米CaCO3对PVC/ACR复合材料的增韧增强机理及在两种环保型材料(Ca/Zn稳定剂和食品级PVC树脂)配方体系中的加工应用情况.结果表明:与普通轻质CaCO3配方对比,添加纳米CaCO3配方体系生产的无毒PVC管材综合物理性能得到提高.

  3. Methane formation from CaCO3 reduction catalyzed by high pressure

    Institute of Scientific and Technical Information of China (English)

    Jin Yang Chen; Lu Jiang Jin; Jun Ping Dong; Hai Fei Zheng; Gui Yang Liu

    2008-01-01

    Under high pressures of several giga-pascals using hydrothermal diamond anvil cell,methane generated directly from CaCO3 reduction in gold-lined chamber is in situ measured by Raman spectroscopy at the temperature of 550 ℃.The reducing agents include FeO,SiO and natural fayalite (Fe2SiO4),and the resource of hydrogen are water and natural serpentine (Mg3Si2O5(OH)4).The study demonstrates the existence of abiogenic formation of methane under high pressures in the Earth's interior and that the application of high pressure to catalyze multicomponent reactions is a very promising method.

  4. Surface Properties of Bacterially-Influenced CaCO3 Mineralization

    Science.gov (United States)

    Cappuccio, J. A.; Pillar, V. D.; Ajo-Franklin, C. M.

    2010-12-01

    Geologic carbon dioxide sequestration, the underground storage of carbon dioxide (CO2), will be an essential component of climate change mitigation. Carbonate minerals are a promising form of stable CO2 storage, but their natural formation is slow. Many microbes can increase the rate of carbonate mineral formation; however the mechanisms of such mineralization are largely unknown. Hypothesized mechanisms include metabolic processes altering pH and supersaturation, as well as cell surface properties of EPS, cell membrane, and S-layers that may alter mineral nucleation. This work investigates these mechanisms by allowing calcium carbonate (CaCO3) to form in the presence or absence of various microbes that are expected to impact these mechanisms. Escherichia coli (E. coli) or Synechocystis sp. PCC 6803 (Syn. sp. 6803) were added to solutions of varying calcium ion concentrations, receiving ammonium carbonate, (NH4)2CO3, by diffusion. The resulting CaCO3 was imaged with an optical microscope in tandem with fluorescent imaging of the bacteria. Surprisingly, formation of calcite was accelerated by the presence of either E. coli or Syn. Sp. 6803 relative to abiotic solutions. This rate acceleration also occurred for metabolically inactive bacteria, indicating that metabolic change was not the operating mechanism. Rather since the calcite crystals increased in number as the cell density increased and both species had similar effects on formation of calcite, we suggest that both bacterial species could play a role in nucleation of calcite crystals. Fluorescent images show that both species of bacteria cluster on the edges and crevices of the crystals, further supporting this idea. Bacterial surface charge was assessed using zeta potential measurements and correlated to biomineralization experiments. From these results, we postulate that the charged bacterial surfaces attract Ca2+ ions, serving as nucleation sites for CaCO3, thereby accelerating crystal formation. These

  5. STUDY ON BIODEGRADABILITY OF POLY (3-HYDROXYBUTYRATE-co-3-HYDROXYVALERATE)/ORGANOPHILIC MONTMORILLONITE NANOCOMPOSITES

    Institute of Scientific and Technical Information of China (English)

    WANG Shufang; SONG Cunjiang; CHEN Guangxin; LIU Jing; YANG Chao; ZHANG Xihui; GUO Tianying; ZHANG Banghua

    2004-01-01

    Poly (3-hydroxybutyrate-co-3-hydroxyvalerate)/Organophilic montmorillonite (PHBV/OMMT) nanocomposites were prepared and the biodegradability of the PHBV/OMMT nanocomposites was studied by a cultivation degrading method in soil suspension. The relationship between structure and biodegradability of PHBV/OMMT nanocomposites was investigated. The results showed that the biodegradability of PHBV/OMMT nanocomposites decreased with increasing amount of OMMT and it was related to the number of PHBV degrading microorganisms in degradation environment, the anti-microbial property of OMMT and the degree of crystallinity of the nanocomposites.

  6. Environmental biodegradation of haloarchaea-produced poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in activated sludge

    DEFF Research Database (Denmark)

    Liu, Xiao-Bin; Wu, Linping; Hou, Jing

    2016-01-01

    Novel poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) copolymers produced by haloarchaea are excellent candidate biomaterials. However, there is no report hitherto focusing on the biodegradation of PHBHV synthesized by haloarchaea. In this study, an environmental biodegradation of haloarchaea......-order copolymer PHBHV-1 (O-PHBHV-1) possessing the highest surface roughness. The order of biodegradation rate was in the opposite trend to the degree of crystallizability of the films. Meanwhile, thermal degradation temperature of most films decreased after biodegradation. Additionally, the surface erosion...

  7. Ordered CoSn-type ternary phases in Co3Sn3-xGex

    DEFF Research Database (Denmark)

    Allred, Jared M.; Jia, Shuang; Bremholm, Martin;

    2012-01-01

    CoSn is the prototype compound of the B35 structure, which has long been of interest due to its rarity and unusually low packing density. We report the synthesis and properties of the solid solution Co3Sn3-xGex for 0 ⩽ x ⩽ 2, in order to clarify the conditions necessary to stabilize such a phase...... some ambiguities about the stabilizing forces in this crystal structure. All compounds are normal metals with room temperature conductivities ranging from 5 to 50 μΩ cm and are weakly paramagnetic....

  8. Synthesis of CaCO3 crystals using hydroxypropylmethyl cellulose hydrogel as template

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jin; LI YanJun; CHENG GuoXiang

    2007-01-01

    Calcium carbonate crystallization was performed in hydrogel of hydroxypropylmethyl cellulose (HPMC). Results showed that the polyhydroxy functionalities in HPMC gel network facilitated the nucleation of aragonite which was not found in experiment without HPMC hydrogel and in experiment using methylcellulose (MC) hydrogel as template. On the other hand,due to the unique assembly of the macromolecules in HPMC hydrogel network,which was different from other hydrogels used in some previous reports,particular crystal morphology,corncob-like CaCO3,was obtained for the first time.

  9. Co3O4 protective coatings prepared by Pulsed Injection Metal Organic Chemical Vapour Deposition

    DEFF Research Database (Denmark)

    Burriel, M.; Garcia, G.; Santiso, J.

    2005-01-01

    Cobalt oxide films were grown by Pulsed Injection Metal Organic Chemical Vapour Deposition (PI-MOCVD) using Co(acac)(3) (acac=acetylacetonate) precursor dissolved in toluene. The structure, morphology and growth rate of the layers deposited on silicon substrates were studied as a function...... of deposition temperature. Pure Co3O4 spinel structure was found for deposition temperatures ranging from 360 to 540 degreesC. The optimum experimental parameters to prepare dense layers with a high growth rate were determined and used to prepare corrosion protective coatings for Fe-22Cr metallic interconnects...

  10. Investigation on the stability of FeCO3 down to the core mantle boundary

    Science.gov (United States)

    Cerantola, Valerio; Bykova, Elena; McCammon, Catherine; Merlini, Marco; Dubrovinsky, Leonid

    2015-04-01

    In the last century, the high intensification of CO2 amount in the atmosphere together with the observed climate change have increasingly focused scientists' attention on the carbon cycle and its evolution at the Earth's surface. However, carbon is continuously transported from the surface into the deep Earth via subduction, mainly by means of carbonates. Fe-bearing carbonates (i.e. FeCO3) in particular are potential carbon carrier down to the deep lower mantle, indeed the presence of iron influences the stability of this phase at high pressures and high temperatures (HPHT), partly due to the spin-pairing of Fe-d electrons. In this study we perform HPHT experiments on FeCO3 in order to study its stability and eventually determine its decomposition products at the relative P and T conditions. Experiments were performed using synthetic FeCO3 crystals in a laser-heated diamond anvil cell (DAC) at 100 GPa an T > 1500 K in order to generate the conditions prevailing in the Earth's lower mantle. X-Ray Single Crystal Diffraction (XRSD) and Synchrotron Mössbauer Source (SMS) analyses were carried out at ESRF and APS synchrotron facilities. All samples were enriched in 57Fe to ensure a strong signal for Mössbauer spectroscopy. At 100 GPa we observed the complete transformation of FeCO3 into two new hp-carbonates, with Fe in different oxidation states depending on the heating temperatures and C in four-fold coordination with O. Laser heating at T > 2000 K generates a new phase with only Fe3+ in the structure: Fe4(CO4)3. Laser heating at 1600 K< T < 2000 K triggers a different redox reaction, where half of the Fe atoms are in 2+ and half in 3+ valence states: Fe(2)2+Fe(2)3+C4O13. Mössbauer spectra confirm the XRSD results by providing the exact amount of Fe-atoms in two different valence states. We assert Fe-rich carbonates can exist in regions down to the core mantle boundary, provided however the presence of an environment with relatively high fO2 e.g. in the proximity

  11. Optical properties of ZnO/BaCO3 nanocomposites in UV and visible regions

    OpenAIRE

    Zak, Ali Khorsand; Hashim, Abdul Manaf; Darroudi, Majid

    2014-01-01

    Pure zinc oxide and zinc oxide/barium carbonate nanoparticles (ZnO-NPs and ZB-NPs) were synthesized by the sol–gel method. The prepared powders were characterized by X-ray diffraction (XRD), ultraviolet–visible (UV–Vis), Auger spectroscopy, and transmission electron microscopy (TEM). The XRD result showed that the ZnO and BaCO3 nanocrystals grow independently. The Auger spectroscopy proved the existence of carbon in the composites besides the Zn, Ba, and O elements. The UV–Vis spectroscopy re...

  12. Three-dimensional macroporous carbon/hierarchical Co3O4 nanoclusters for nonenzymatic electrochemical glucose sensor

    Science.gov (United States)

    Wang, Li; Zhang, Yayun; Xie, Yingzhen; Yu, Jie; Yang, Han; Miao, Longfei; Song, Yonghai

    2017-04-01

    A novel supporting material named as three-dimensional kenaf stem-derived carbon (3D-KSCs) was used to load hierarchical Co3O4 nanoclusters for electrochemical sensing glucose. The 3D-KSCs/hierarchical Co3O4 nanoclusters were constructed by two steps. Los of acicular precursor nanoclusters firstly grew on the channels of 3D-KSCs densely by hydrothermal method and then the as-prepared 3D-KSCs/hierarchical Co3O4 nanoclusters was obtained by thermal pyrolysis of the 3D-KSCs/precursors nanocomposites at 400 °C. The 3D macroporous configuration of 3D-KSCs resulted in lots of hierarchical Co3O4 nanoclusters arrayed on the surface of 3D-KSCs owing to its large enough specific surface area, which effectively avoided their aggregations and improved the stability of nanocomposites. The obtained 3D-KSCs/hierarchical Co3O4 nanoclusters showed a large number of needle-shaped and layered Co3O4 nanoclusters uniformly grew on the macropore's walls of 3D-KSC. Due to its unique nanostructures, the 3D-KSCs/hierarchical Co3O4 nanoclusters integrated electrode showed superior performance for nonenzymatic electrochemical glucose sensing, showing wide linear range (0.088-7.0 mM) and low detection limit of 26 μM. It might be a new strategy to prepare nanostructures on 3D-KSC for future applications.

  13. Studies of Nano-sized Co3O4 as Anode Materials for Lithium-ion Batteries

    Institute of Scientific and Technical Information of China (English)

    HUANG, Fenga; ZHAN, Hui; ZHOU, Yun-Hong

    2003-01-01

    The structural evolution of the Co3O4 fine powders prepared by rheological phase reaction and pyrolysis method upon different temperature has been investigated using X-ray diffraction (XRD) topography. The electrochemical performance of Co3O4electrode materials for Li-ion batteries is studied in the form of Li/Co3O4 cells. The reversible capacity as high as 930 mAh/g for the Co3O4 sample heat-treated at 600 C is achieved and sustained over 30 times charge-discharge cycles at room temperature. The detailed information concerning the reaction mechanism of Co3O4 active material together with lithium ion is obtained through ex-situ XRD topography, X-ray photoelectron spectroscopy (XPS) analysis and cyclic voltammetry (CV) technique. And it is revealed that a "two-step" reaction is involved in the charge and discharge of the Li/Co3O4 cells, in which Co3O4 active material is reversibly reduced into xCo·(3 - x )CoO and then into metallic Co.

  14. Facile Synthesis of SrCO3-Sr(OH2/PPy Nanocomposite with Enhanced Photocatalytic Activity under Visible Light

    Directory of Open Access Journals (Sweden)

    Alfredo Márquez-Herrera

    2016-01-01

    Full Text Available Pyrrole monomer was chemically polymerized onto SrCO3-Sr(OH2 powders to obtain SrCO3-Sr(OH2/polypyrrole nanocomposite to be used as a candidate for photocatalytic degradation of methylene blue dye (MB. The material was characterized by Fourier transform infrared (FTIR spectroscopy, UV/Vis spectroscopy, and X-ray diffraction (XRD. It was observed from transmission electronic microscopy (TEM analysis that the reported synthesis route allows the production of SrCO3-Sr(OH2 nanoparticles with particle size below 100 nm which were embedded within a semiconducting polypyrrole matrix (PPy. The SrCO3-Sr(OH2 and SrCO3-Sr(OH2/PPy nanocomposites were tested in the photodegradation of MB dye under visible light irradiation. Also, the effects of MB dye initial concentration and the catalyst load on photodegradation efficiency were studied and discussed. Under the same conditions, the efficiency of photodegradation of MB employing the SrCO3-Sr(OH2/PPy nanocomposite increases as compared with that obtained employing the SrCO3-Sr(OH2 nanocomposite.

  15. Study of the strength and erosive behavior of CaCO3/glass fiber reinforced polyester composite

    Directory of Open Access Journals (Sweden)

    2008-12-01

    Full Text Available In this study, the strength and erosive characteristics of CaCO3 filled unsaturated polyester/glass fiber (UPR/GFR composite are evaluated. Samples of UPR with 40, 50 and 60 wt% content of CaCO3 and different CaCO3 particle sizes of 1, 2, 3, 5 and 10 micron were prepared and tested under tensile loading, indentation and erosion conditions. The tensile strength, hardness and erosion wear rate of unsaturated polyester/glass fiber (UPR composite/CaCO3 composite were obtained and evaluated. The results showed that the higher is the percentage of CaCO3 in the composite and the smaller is the CaCO3 particle size, the higher is the strength and the erosive resistance of the glass fiber reinforced/unsaturated polyester composite (UPR-GFR. Furthermore, the highest erosion wear rate is at 90° impingement angle. Finally the results show that the erosive wear of CaCO3 content UPR/GFR composite in a brittle manner.

  16. Polymer blends made of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) and epoxidized natural rubber: Thermal and mechanical response

    Science.gov (United States)

    Salim, Yoga Sugama; Han, Chan Chin; Kammer, Hans-Werner; Kumar, Sudesh; Neon, Gan Seng

    2015-08-01

    The ever-increasing demand of biodegradable over conventional polymers places microbial polyhydroxyalkanoates (PHA) as an ideal choice of research material for specific applications. In this study, polymer blends made of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx) and epoxidized natural rubber (ENR) were prepared using solution casting technique. The influence of ENR on thermal, morphological and mechanical properties of P(3HB-co-3HHx) was investigated. There are two glass transition (Tg) temperatures observed using differential scanning calorimeter. This indicates that P(3HB-co-3HHx) and ENR are immiscible at macroscopic level. Although the Tg of P(3HB-co-3HHx) is seen to shift toward ENR in the least manner, infrared analysis suggests that the crystal structure of P(3HB-co-3HHx) retains its conformational structure. In terms of morphology, ENR exists as droplets in P(3HB-co-3HHx)-rich phase, e.g. at ENR weight fraction (wENR) of 0.3. In dynamic mechanical analysis, all blend compositions exhibit solid-like behavior, with storage moduli larger than loss moduli, across the frequency sweep at room temperature.

  17. An alternative model for CaCO3 over-shooting during the PETM: Biological carbonate compensation

    Science.gov (United States)

    Luo, Yiming; Boudreau, Bernard P.; Dickens, Gerald R.; Sluijs, Appy; Middelburg, Jack J.

    2016-11-01

    Decreased CaCO3 content of deep-sea sediments argues for rapid and massive acidification of the oceans during the Paleocene-Eocene Thermal Maximum (PETM, ∼56 Ma BP). In the course of the subsequent recovery from this acidification, sediment CaCO3 content came to exceed pre-PETM levels, known as over-shooting. Past studies have largely attributed the latter to increased alkalinity input to the oceans via enhanced weathering, but this ignores potentially important biological factors. We successfully reproduce the CaCO3 records from Walvis Ridge in the Atlantic Ocean, including over-shooting, using a biogeochemical box model. Replication of the CaCO3 records required: 1) introduction of a maximum of ∼6500 GtC of CO2 directly into deep-ocean waters or ∼8000 GtC into the atmosphere, 2) limited deep-water exchange between the Indo-Atlantic and Pacific oceans, 3) the disappearance of sediment bioturbation during a portion of the PETM, and 4) most central to this study, a ∼50% reduction in net CaCO3 production, during acidification. In our simulations, over-shooting is an emergent property, generated at constant alkalinity input (no weathering feedback) as a consequence of attenuated CaCO3 productivity. This occurs because lower net CaCO3 production from surface waters allows alkalinity to build-up in the deep oceans (alkalinization), thus promoting deep-water super-saturation. Restoration of CaCO3 productivity later in the PETM, particularly in the Indo-Atlantic Ocean, leads to greater accumulation of CaCO3, ergo over-shooting, which returns the ocean to pre-PETM conditions over a time scale greater than 200 ka.

  18. 马来酸酐对PVC/CaCO3力学性能的影响

    Institute of Scientific and Technical Information of China (English)

    许家友; 郭少云

    2007-01-01

    在PVC加工过程中,通过共混,使马来酸酐(MAH)中的双键与PVC降解形成的共轭双键发生Diels—Alder加成反应,MAH接枝到PVC分子链上,改善了PVC与CaCO3的相容性,提高了PVC与CaCO3的粘接力,从而提高了PVC/CaCO3的力学强度。

  19. Improved electrochemical properties by lithium insertion into Co3O4 in aqueous LiOH solution

    Institute of Scientific and Technical Information of China (English)

    Yan Liu; Chengkang Chang; Dongyun Zhang; Ying Wu

    2013-01-01

    Co3O4 microspheres were synthesized by a simple hydrothermal treatment. The first-cycle charge-discharge tests were carried out between 0.6 and 0.6 V vs. SCE. The pristine, discharged and recharged specimens were characterized by X-ray power diffraction and scanning electron microscopy. Cyclic voltammetry (CV) curves of Co3O4 at various concentrations in LiOH solution were investigated. The appearance of the two pairs of redox peaks indicated that two sets of faradaic reactions were involved in the redox reactions of Co3O4 to LiCoO2 and LiHCoO2.

  20. Influence of Block Copolymer on Formation and Acid Resistant Properties of Hybrid CaCO3 Particles

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-dong; HU Qiao-ling; ZHAO Shi-fang; SHEN Jia-cong

    2009-01-01

    Block copolymer polystyrene-b-poly(acrylic acid)(PS-b-PAA) was used as structural template for the synthesis of CaCO3 microparticles. Through this procedure, acid resistant hybrid CaCO3 micro-spheres were obtained. Acid resistant properties of this type of hybrid CaCO3 were studied. Size mea-surement shows that the acid resistant properties of the hybrid particles are different in different solutions, such as HCI, EDTA, and H2SO4 solutions.

  1. Influence of electromagnetic field intensity on the metastable zone width of CaCO3 crystallization in circulating water

    Science.gov (United States)

    Wang, Jianguo; Liang, Yandong; Chen, Si

    2016-09-01

    In this study, changes in the metastable zone width of CaCO3 crystallization was determined through conductivity titration by altering electromagnetic field parameters applied to the circulating water system. The critical conductivity value and metastable zone curves of CaCO3 crystallization were determined under different solution concentrations and electromagnetic field intensities. Experimental results indicate that the effect of the electromagnetic field intensity on the critical conductivity value intensifies with the increase of solution concentration. Moreover, the metastable zone width of CaCO3 crystallization increases with the increase of electromagnetic field intensity within 200 Gs, thereby prolonging the induction period of nucleation.

  2. THE EFFECT OF MATRIX TOUGHNESS ON THE BRITTLE-DUCTILE TRANSITION OF HDPE/CaCO3 BLENDS

    Institute of Scientific and Technical Information of China (English)

    FU Qiang; ZHANG Yulin; WANG Guiheng

    1994-01-01

    The effects of HDPE matrix toughness on the brittle-ductile transition of HDPE/CaCO3 blends are investigated. Not all HDPE can be toughened by CaCO3 particles. The ability of the matrix to yield plays a fundamental role in determing whether HDPE can be toughened or not.There exists a critical matrix toughness (Isc≈45J/m) below which HDPE can not be toughened observably by CaCO3 particle at given average size, and above which the critical matrix ligament thickness (τc) is proportional to matrix impact strength.

  3. The growth of urchin-like Co3O4 directly on sensor substrate and its gas sensing properties

    Science.gov (United States)

    Shen, Shui Fa; Xu, Mei Li; Lin, Dong Bao; Pan, Hai Bo

    2017-02-01

    Urchin-like Co3O4 has successfully grown directly on ITO glass and sensor ceramic substrate through hydrothermal reaction followed by calcination. The combined characterizations of X-ray diffraction (XRD) patterns, nitrogen adsorption-desorption and scanning electron microscopy (SEM) indicate that the as-prepared product possesses good crystallinity, large specific surface area and urchin-like morphology which is greatly influenced by the reaction additives. The sensor with urchin-like Co3O4 growing directly on ceramic sensor tube exhibits higher response sensitivity than the sensors fabricated with other morphological Co3O4 or by traditional coating method.

  4. Studies on the mechanochemical reinforcing and toughening of nano-CaCO3 filled PVC composites%纳米CaCO3填充PVC复合材料的力化学增强增韧研究

    Institute of Scientific and Technical Information of China (English)

    田满红; 郭少云

    2003-01-01

    利用振动球磨机对纳米CaCO3进行表面改性,将改性的纳米CaCO3加入PVC中制备PVC/CaCO3复合材料,并对其力学性能进行了研究.结果表明:通过力化学改性CaCO3后,可使其在PVC基体中的分散性和界面相互作用增强,导致其冲击强度、断裂伸长率、拉伸模量大幅增加,而拉伸强度保持不变甚至略有增加.

  5. Biodiesel synthesis using K2CO3/Al–O–Si aerogel catalysts

    Directory of Open Access Journals (Sweden)

    IVANA LUKIĆ

    2010-06-01

    Full Text Available In this study, catalysts for fatty acid methyl esters (FAME or bio-diesel synthesis with K2CO3 as the active component on an alumina/silica support were synthesized using the sol–gel method, which was followed by drying the “dense” wet gels with supercritical carbon dioxide to obtain the aerogels. The prepared catalysts were characterized by XRD analysis, FTIR spectroscopy and N2 physisorption at 77 K, and tested in the methanolysis of sunflower oil. The effects of reaction variables, such as reaction time, temperature and methanol to oil molar ratio, on the yield of FAME were investigated. The aerogel catalysts with K2CO3 as the active component on an alumina/silica support exhibited good activity in the methanolysis of sunflower oil. The leaching of potassium when the catalyst was in contact with pure methanol under the working conditions of methanolysis was also tested in this study, indicating that it occurred only at higher temperatures, while at lower ones, it was negligible.

  6. Biodiesel preparation from Jatropha curcas oil catalyzed by hydrotalcite loaded with K2CO3.

    Science.gov (United States)

    Teng, Guangyuan; Gao, Lijing; Xiao, Guomin; Liu, Hu; Lv, Jianhua

    2010-11-01

    This paper discusses the synthesis of biodiesel catalyzed by solid base of K(2)CO(3)/HT using Jatropha curcas oil as feedstock. Mg-Al hydrotalcite was prepared using co-precipitation methods, in which the molar ratio of Mg to Al was 3:1. After calcined at 600 degrees C for 3 h, the Mg-Al hydrotalcite and K(2)CO(3) were ground and mixed according to certain mass ratios, in which some water was added. The mixture was dried at 65 degrees C, and after that it was calcined at 600 degrees C for 3 h. Then, this Mg-Al hydrotalcite loaded with potassium carbonate was obtained and used as catalyst in the experiments. Analyses of XRD and SEM characterizations for catalyst showed the metal oxides formed in the process of calcination brought about excellent catalysis effect. In order to achieve the optimal technical reaction condition, five impact factors were also investigated in the experiments, which were mass ratio, molar ratio, reaction temperature, catalyst amount and reaction time. Under the best condition, the biodiesel yield could reach up to 96%.

  7. Microstructure and Mechanical Properties of CaCO3 Whisker-reinforced Cement

    Institute of Scientific and Technical Information of China (English)

    CAO Mingli; WEI Jianqiang

    2011-01-01

    Composite Portland cement (PC) played an important role in various kinds of construction engineering owing to low hydration heat,low-cost,and application of solid industrial waste,but its brittleness and low strength limited its use in stress-bearing locations.The aim of this study is to improve the toughness and fracture resistance by incorporating CaCO3 whisker in cement matrix.Effect of different content of calcium carbonate whiskers on the mechanical properties of PC was investigated.The results showed that the flexural strength,impact strength and split tensile strength were increased by 39.7%,39.25% and 36.34% at maximum,respectively.Microstructure and elements of the whiskers in hardened cement were observed and analyzed by SEM/EDS.The mechanisms of the reinforcement of CaCO3 whisker on cement were also discussed,and the conclusion was that the improvement could be correlated to energy-dissipating processes owing to crack bridging,crack deflection,and whisker pull-out at the crack tips.

  8. The JCMT 12CO(3-2) Survey of the Cygnus X Region: I. A Pathfinder

    CERN Document Server

    Gottschalk, M; Matthews, H E; Landecker, T L; Dent, W R F

    2012-01-01

    Cygnus X is one of the most complex areas in the sky. This complicates interpretation, but also creates the opportunity to investigate accretion into molecular clouds and many subsequent stages of star formation, all within one small field of view. Understanding large complexes like Cygnus X is the key to understanding the dominant role that massive star complexes play in galaxies across the Universe. The main goal of this study is to establish feasibility of a high-resolution CO survey of the entire Cygnus X region by observing part of it as a Pathfinder, and to evaluate the survey as a tool for investigating the star-formation process. A 2x4 degree area of the Cygnus X region has been mapped in the 12CO(3-2) line at an angular resolution of 15" and a velocity resolution of ~0.4km/s using HARP-B and ACSIS on the James Clerk Maxwell Telescope. The star formation process is heavily connected to the life-cycle of the molecular material in the interstellar medium. The high critical density of the 12CO(3-2) trans...

  9. Magnetic phase transitions and structures of Co 3V 2O 8

    Science.gov (United States)

    Qureshi, N.; Fuess, H.; Ehrenberg, H.; Hansen, T. C.; Schwabe, D.

    2007-04-01

    Co 3V 2O 8 is a spin- 3/2 system on a Kagomé staircase and is known to undergo two magnetic phase transitions between 6 and 11 K. The H-T phase diagram of Co 3V 2O 8 derived by magnetization measurements on a single crystal is presented. Additionally both ordered magnetic structures were investigated by neutron powder diffraction experiments and solved using Bertaut's macroscopic theory. For the ferromagnetic phase the magnetic moments of the Co 2+ ions were found to be 1.5(3)μB and 2.7(1)μB at 3.5 K along the crystallographic a axis for the (4a) and (8e) sites, respectively. The antiferromagnetic phase exhibits a magnetic cell with a doubled b axis with respect to the nuclear one. The magnetic moments point along the a axis being 1.8(2)μB (4a) and 1.8(1)μB (8e) at 8 K.

  10. Effect of Na_2CO_3 Stress on Seed Germination of Radish%Na_2CO_3胁迫对萝卜种子萌发的影响

    Institute of Scientific and Technical Information of China (English)

    夏瑾华; 叶利民; 邱娟娟; 李亚娟

    2012-01-01

    Taking radish seed as material,the effect of Na2CO3 stress on seed germination of radish was studied.The results showed that 2 mmol·L-1 Na2CO3 promoted the germination rate,germination potention,germination index,vigor index,germ length,radicle length and fresh weight of radish embryo.The concentrate of Na2CO3 above 5 mmol·L-1 significantly inhibited radish seed germination.The concentrate of Na2CO3 above 5 mmol·L-1 significantly inhibited radicle length.The concentrate of Na2CO3 above 10 mmol·L-1 significantly inhibited germ length.%以萝卜(Raphanus sativus L.)种子为材料,采用纸上萌发法研究了不同浓度的Na2CO3对萝卜种子萌发的影响。结果表明:2mmol·L-1的Na2CO3处理对萝卜种子的发芽率、发芽势、发芽指数、活力指数、胚芽长、胚根长和胚鲜重等均有一定的促进作用。显著抑制萝卜种子萌发的Na2CO3浓度为5mmol·L-1,显著抑制胚根生长的浓度为5mmol·L-1,显著抑制胚芽生长的浓度为10mmol·L-1。

  11. Photocatalytic Oxidation of Reactive Dye Using Co3O4 Catalyst%用Co3O4催化剂光催化氧化活性染料

    Institute of Scientific and Technical Information of China (English)

    娄向东; 韩珺; 楚文飞; 王学锋; 成庆堂

    2007-01-01

    以沉淀-热解法制备了纳米级Co3O4催化剂,并用X射线衍射仪、红外光谱仪对Co3O4催化剂进行了表征.以300 W高压汞灯为光源,研究了Co3O4催化剂对不同活性染料的光催化氧化活性.实验结果表明:在活性染料质量浓度为20 mg/L、250 mL染料溶液中Co3O4催化剂加入量为150 mg、反应2 h 的条件下,Co3O4催化剂对B-GFF黑、B-RN蓝、K-NR艳蓝3种活性染料溶液的脱色率分别为95%,87%,77%;适当加入酸或碱有利于提高处理效率,反应后染料溶液的pH为7.12~8.37,染料溶液初始pH为10.00时的脱色率最高为100%; Co3O4催化剂具有一定的再利用价值.

  12. 纳米CaCO3/高分子复合材料的研究进展%Recent progress in research on nano-CaCO3/polymer composites

    Institute of Scientific and Technical Information of China (English)

    龙盛如; 黄锐; 杨杰

    2004-01-01

    简述了纳米CaCO3/高分子复合材料研究的进展,重点介绍了纳米CaCO3与不同类型高分子制得的复合材料的结构及性能.对纳米CaCO3进行适当分散处理,加强粒子与基体的相互作用,使纳米CaCO3能够在基体中均匀分散,从而可提高复合材料的综合性能,拓宽纳米CaCO3的使用范围.寻求最佳的工业化方法对纳米CaCO3进行表面改性,制得稳定的高性能复合材料,实现工业化是这一领域的研究方向.

  13. Preparation and Mechanical Properties of UPVC/nano-CaCO3 in Strong Interface Adhesion%强界面PVC-U/nano-CaCO3的制备与力学性能研究

    Institute of Scientific and Technical Information of China (English)

    王华; 刘晓明

    2005-01-01

    使用自主合成的端羧基聚酯和端叔胺基羧酸分别对水乳液中的nano-CaCO3进行表面处理,制备了可与PVC形成界面分子物理纠缠或热可逆交联的强界面结合能力的nano-CaCO3.研究了PVC-U/nano-CaCO3的力学性能与CaCO3的表面性质、填充量及表面处理剂分子量等因素的关系.研究结果表明,提高界面结合强度可改善CaCO3在基材中的分散状况并提高PVC-U/nano-CaCO3的屈服强度,却对于提高PVC的冲击能力无明显效果.

  14. HIV-1 infection and first line ART induced differential responses in mitochondria from blood lymphocytes and monocytes: the ANRS EP45 "Aging" study.

    Directory of Open Access Journals (Sweden)

    Sophie Perrin

    Full Text Available BACKGROUND: The ANRS EP45 "Aging" study investigates the cellular mechanisms involved in the accelerated aging of HIV-1 infected and treated patients. The data reported focus on mitochondria, organelles known to be involved in cell senescence. METHODS: 49 HIV-1 infected patients untreated with antiretroviral therapy, together with 49 seronegative age- and sex-matched control subjects and 81 HIV-1 infected and treated patients, were recruited by 3 AIDS centres (Marseille, Montpellier, Nice; France; http://clinicaltrials.gov/, NCT01038999. In more than 88% of treated patients, the viral load was 500/mm(3. ROS (reactive oxygen species production and ΔΨm (inner membrane potential were measured by flow cytometry in blood lymphocytes and monocytes (functional parameters. Three mitochondrial network quantitative morphological parameters were computed using confocal microscopy and image analysis. Three PBMC mitochondrial proteins (porin and subunits 2 and 4 of cytochrome C oxidase encoded by mtDNA or nuclear DNA, respectively were analysed by western blotting. RESULTS: Quantitative changes in PBMC mitochondrial proteins were not induced by either HIV-1 infection or ART. Discriminant analysis integrating functional (ROS production and ΔΨm or morphological (network volume density, fragmentation and branching parameters revealed HIV-1 infection and ART differential effects according to cell type. First line ART tended to rescue lymphocyte mitochondrial parameters altered by viral infection, but induced slight changes in monocytes. No statistical difference was found between the effects of three ART regimens on mitochondrial parameters. Correlations between functional parameters and viral load confirmed the damaging effects of HIV-1 in lymphocyte mitochondria. CONCLUSIONS: In patients considered to be clinically stable, mitochondria exhibited functional and morphological modifications in PBMCs resulting from either direct or indirect effects of HIV-1

  15. Influence of Alpha-1 Glycoprotein Acid Concentrations and Variants on Atazanavir Pharmacokinetics in HIV-Infected Patients Included in the ANRS 107 Trial▿

    Science.gov (United States)

    Barrail-Tran, A.; Mentré, F.; Cosson, C.; Piketty, C.; Chazallon, C.; Gérard, L.; Girard, P. M.; Taburet, A. M.

    2010-01-01

    Atazanavir is an HIV-1 protease inhibitor with high protein binding in human plasma. The objectives were first to determine the in vitro binding characteristics of atazanavir and second to evaluate whether plasma protein binding to albumin and alpha-1 glycoprotein acid (AAG) influences the pharmacokinetics of atazanavir in HIV-infected patients. For the in vitro study, atazanavir protein binding characteristics were determined in AAG- and albumin-containing purified solutions. Atazanavir was found to bind AAG on a high-affinity saturable site (association constant, 4.61 × 105 liters/mol) and albumin on a low-affinity nonsaturable site. For the in vivo study, blood samples from 51 patients included in trial ANRS 107—Puzzle 2 were drawn prior to drug intake at week 6. For 10 patients included in the pharmacokinetic substudy, five additional blood samples were collected during one dosing interval at week 6. Atazanavir concentrations were assayed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Albumin concentrations, AAG concentrations, and phenotypes were also measured in these patients. Concentrations of atazanavir were modeled using a population approach. A one-compartment model with first-order absorption and elimination best described atazanavir pharmacokinetics. Atazanavir pharmacokinetic parameters and their interindividual variabilities were as follows: absorption rate constant (ka), 0.73 h−1 (139.3%); apparent clearance (CL/F), 13.3 liters/h (26.7%); and apparent volume of distribution (V/F), 79.7 liters (27.0%). Atazanavir CL/F decreased significantly when alanine aminotransferase and/or AAG levels increased (P < 0.01). The ORM1*S phenotype also significantly increased atazanavir V/F (P < 0.05). These in vivo results indicate that atazanavir pharmacokinetics is moderately influenced by its protein binding, especially to AAG, without expected clinical consequences. PMID:19995932

  16. Influence of alpha-1 glycoprotein acid concentrations and variants on atazanavir pharmacokinetics in HIV-infected patients included in the ANRS 107 trial.

    Science.gov (United States)

    Barrail-Tran, A; Mentré, F; Cosson, C; Piketty, C; Chazallon, C; Gérard, L; Girard, P M; Taburet, A M

    2010-02-01

    Atazanavir is an HIV-1 protease inhibitor with high protein binding in human plasma. The objectives were first to determine the in vitro binding characteristics of atazanavir and second to evaluate whether plasma protein binding to albumin and alpha-1 glycoprotein acid (AAG) influences the pharmacokinetics of atazanavir in HIV-infected patients. For the in vitro study, atazanavir protein binding characteristics were determined in AAG- and albumin-containing purified solutions. Atazanavir was found to bind AAG on a high-affinity saturable site (association constant, 4.61x10(5) liters/mol) and albumin on a low-affinity nonsaturable site. For the in vivo study, blood samples from 51 patients included in trial ANRS 107--Puzzle 2 were drawn prior to drug intake at week 6. For 10 patients included in the pharmacokinetic substudy, five additional blood samples were collected during one dosing interval at week 6. Atazanavir concentrations were assayed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Albumin concentrations, AAG concentrations, and phenotypes were also measured in these patients. Concentrations of atazanavir were modeled using a population approach. A one-compartment model with first-order absorption and elimination best described atazanavir pharmacokinetics. Atazanavir pharmacokinetic parameters and their interindividual variabilities were as follows: absorption rate constant (ka), 0.73 h(-1) (139.3%); apparent clearance (CL/F), 13.3 liters/h (26.7%); and apparent volume of distribution (V/F), 79.7 liters (27.0%). Atazanavir CL/F decreased significantly when alanine aminotransferase and/or AAG levels increased (P<0.01). The ORM1*S phenotype also significantly increased atazanavir V/F (P<0.05). These in vivo results indicate that atazanavir pharmacokinetics is moderately influenced by its protein binding, especially to AAG, without expected clinical consequences.

  17. Unprecedented therapeutic potential with a combination of A2A/NR2B receptor antagonists as observed in the 6-OHDA lesioned rat model of Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Anne Michel

    Full Text Available In Parkinson's disease, the long-term use of dopamine replacing agents is associated with the development of motor complications; therefore, there is a need for non-dopaminergic drugs. This study evaluated the potential therapeutic impact of six different NR2B and A2A receptor antagonists given either alone or in combination in unilateral 6-OHDA-lesioned rats without (monotherapy or with (add-on therapy the co-administration of L-Dopa: Sch-58261+ Merck 22; Sch-58261+Co-101244; Preladenant + Merck 22; Preladenant + Radiprodil; Tozadenant + Radiprodil; Istradefylline + Co-101244. Animals given monotherapy were assessed on distance traveled and rearing, whereas those given add-on therapy were assessed on contralateral rotations. Three-way mixed ANOVA were conducted to assess the main effect of each drug separately and to determine whether any interaction between two drugs was additive or synergistic. Additional post hoc analyses were conducted to compare the effect of the combination with the effect of the drugs alone. Motor activity improved significantly and was sustained for longer when the drugs were given in combination than when administered separately at the same dose. Similarly, when tested as add-on treatment to L-Dopa, the combinations resulted in higher levels of contralateral rotation in comparison to the single drugs. Of special interest, the activity observed with some combinations could not be described by a simplistic additive effect and involved more subtle synergistic pharmacological interactions. The combined administration of A2A/NR2B-receptor antagonists improved motor behaviour in 6-OHDA rats. Given the proven translatability of this model such a combination may be expected to be effective in improving motor symptoms in patients.

  18. Is clinical practice concordant with the changes in guidelines for antiretroviral therapy initiation during primary and chronic HIV-1 infection? The ANRS PRIMO and COPANA cohorts.

    Directory of Open Access Journals (Sweden)

    Evguenia Krastinova

    Full Text Available Guidelines for initiating HIV treatment are regularly revised. We explored how physicians in France have applied these evolving guidelines for ART initiation over the last decade in two different situations: chronic (CHI and primary HIV-1 infection (PHI, since specific recommendations for PHI are also provided in France.Data came from the ANRS PRIMO (1267 patients enrolled during PHI in 1996-2010 and COPANA (800 subjects enrolled at HIV diagnosis in 2004-2008 cohorts. We defined as guidelines-inconsistent during PHI and CHI, patients meeting criteria for ART initiation and not treated in the following month and during the next 6 months, respectively.ART initiation during PHI dramatically decreased from 91% of patients in 1996-99 to 22% in 2007 and increased to 60% in 2010, following changes in recommendations. In 2007, however, after the CD4 count threshold was raised to 350 cells/mm(3 in 2006, only 55% of the patients with CD4≤350 were treated and 66% in 2008. During CHI, ART was more frequently initiated in patients who met the criteria at entry (96% than during follow-up: 83% when recommendation to treat was 200 and 73% when it was 350 cells/mm(3. Independent risk factors for not being treated during CHI despite meeting the criteria were lower viral load, lower educational level, and poorer living conditions.HIV ART initiation guidelines are largely followed by practitioners in France. What can still be improved, however, is time to treat when CD4 cell counts reach the threshold to treat. Risk factors for lack of timely treatment highlight the need to understand better how patients' living conditions and physicians' perceptions influence the decision to initiate treatment.

  19. Emtricitabine seminal plasma and blood plasma population pharmacokinetics in HIV-infected men in the EVARIST ANRS-EP 49 study.

    Science.gov (United States)

    Valade, Elodie; Tréluyer, Jean-Marc; Illamola, Silvia M; Bouazza, Naïm; Foissac, Frantz; De Sousa Mendes, Maïlys; Lui, Gabrielle; Chenevier-Gobeaux, Camille; Suzan-Monti, Marie; Rouzioux, Christine; Assoumou, Lambert; Viard, Jean-Paul; Hirt, Déborah; Urien, Saïk; Ghosn, Jade

    2015-11-01

    We aimed to describe blood plasma (BP) and seminal plasma (SP) pharmacokinetics of emtricitabine (FTC) in HIV-1-infected men, assess its penetration in the male genital tract, and evaluate its impact on seminal plasma HIV load (spVL) detection. Men from the EVARIST ANRS EP49 study receiving combined antiretroviral therapy with FTC and with suppressed BP viral load were included in the study. A total of 236 and 209 FTC BP and SP concentrations, respectively, were available. A population pharmacokinetic model was developed with Monolix 4.1.4. The impact of FTC seminal exposure on spVL detection was explored by receiver operating characteristic (ROC) curves and mixed-effects logistic regressions. FTC BP pharmacokinetics was described by a two-compartment model. The addition of an effect compartment with different input and output constants best described FTC SP pharmacokinetics. No covariates were found to explain the variability in SP. FTC exposures (area under the concentration-time curve from 0 to 24 h [AUC0-24]) were higher in SP than in BP (median AUC0-24, 38.04 and 12.95 mg · liter(-1) · h, respectively). The median (range) SP-to-BP AUC0-24 ratio was 2.91 (0.84 to 10.08). Less than 1% of FTC AUC0-24 ratios were lower than 1. The impact of FTC SP AUC0-24 or FTC SP-to-BP AUC0-24 ratio on spVL detection was not significant (P = 0.943 or 0.893, respectively). This is the first population model describing FTC pharmacokinetics simultaneously in both BP and SP. FTC distributes well in the male genital tract with higher FTC concentrations in SP than in BP. FTC seminal plasma exposures were considered efficient in the majority of men.

  20. Suicide risk in a representative sample of people receiving HIV care: Time to target most-at-risk populations (ANRS VESPA2 French national survey)

    Science.gov (United States)

    Fressard, Lisa; Préau, Marie; Sagaon-Teyssier, Luis; Suzan-Monti, Marie; Guagliardo, Valérie; Mora, Marion; Roux, Perrine; Dray-Spira, Rosemary; Spire, Bruno

    2017-01-01

    Background Suicide risk is high among people living with HIV (PLHIV). This study aimed to identify major correlates of suicide risk in a representative sample of PLHIV in France, in order to help target individuals who would benefit from suicide risk screening and psychiatric care. Methods The ANRS VESPA2 cross-sectional survey (April 2011-January 2012) collected socio-demographic, medical and behavioral data from 3,022 PLHIV recruited in 73 French HIV hospital departments. The study sample comprised the 2,973 participants with available self-reported data on suicide risk (defined as having either thought about and planned to commit suicide during the previous 12 months or attempted suicide during the same period of time) and medical data on comorbidities. Weighted Poisson models adjusted for HCV co-infection and significant clinical variables were used to estimate the relationship between suicide risk and HIV transmission groups, experience with HIV disease and other psychosocial factors. Results Suicide risk was reported by 6.3% of PLHIV in the study sample. After adjustment for HIV immunological status and HCV co-infection, women (IRR [95%CI]:1.93 [1.17; 3.19]) and men who have sex with men (MSM) (1.97 [1.22; 3.19]) had a higher suicide risk than the rest of the sample. Moreover, the number of discrimination-related social contexts reported (1.39 [1.19; 1.61]), homelessness (4.87 [1.82; 13.02]), and reporting a feeling of loneliness (4.62 [3.06; 6.97]) were major predictors of suicide risk. Conclusions Reducing the burden of precarious social conditions and discrimination is an important lever for preventing suicide risk among PLHIV in France. Comprehensive care models involving peer/community social interventions targeted at women and MSM need to be implemented to lower the risk of suicide in these specific subgroups of PLHIV. PMID:28192455

  1. In situ FT-IR study on CO oxidation over Co3O4/CeO2 catalyst%Co3O4/CeO2CO氧化的原位红外光谱研究

    Institute of Scientific and Technical Information of China (English)

    邵建军; 朱锡; 张永坤; 王明贵

    2012-01-01

    Co3O4/CeO2 catalyst was prepared by co-precipitation-oxidation method. Adsorption of carbon monoxide and the co-adsorption of CO/O2 over Co3O4/CeO2 sample were investigated. In situ FT-IR analysis of the mechanism in CO oxidation was interpreted over Co3O4/CeO2 sample. Effects of the reaction conditions on the catalytic performance over Co3O4/CeO2 catalyst for carbon monoxide oxidation was investigated at humid and dry conditions. Results indicated that the addition of cerium to the cobalt oxide was beneficial for CO oxidation over Co3O4 at humid condition. The formation of carbonate species with reaction on Co3O4/CeO2 composite oxide slightly deactivated the catalyst. When the temperature was as low as 453 K, the dynamic equilibrium of formation and decomposition of carbonate species existed in Co3O4/CeO2 composite oxide catalyst. The carbonate species disappeared above 493 K. The strong interaction between CeO2 and Co3O4 may contribute to the excellent water resistance for low-temperature CO oxidation over Co3O4/CeO2 catalyst at humid condition.%采用沉淀氧化法制备了Co3O4/CeO2催化剂.分别在干、湿条件下进行了一氧化碳氧化反应研究.运用FT-IR表征手段,在钴铈复合氧化物上进行了CO吸附及CO/O2共吸附研究.结果表明,与纯的Co3O4样品相比,Co3O4/CeO2具有明显的抗湿气能力.Co3O4/CeO2催化剂在进行CO氧化时,表面形成了类碳酸盐物种.当环境温度低于453K时,催化剂上类碳酸盐的生成与形成类碳酸盐物种后受热分解存在着动态平衡.当环境温度高于493K,催化剂上生成的类碳酸盐物全部受热分解.氧化铈的加入提高了催化剂的抗湿气性能.较小粒径的Co3O4与CeO2产生的强相互作用可使CeO2向Co3O4提供氧,因而间接提供了CO氧化需要的氧.

  2. Enhanced performance of a biomimetic membrane for Na2CO3 crystallization in the scenario of CO2 capture

    DEFF Research Database (Denmark)

    Ye, Wenyuan; Lin, Jiuyang; Tækker Madsen, Henrik

    2016-01-01

    Membrane assisted crystallization (MACr) offers an innovative platform for crystallizing Na2CO3, allowing its reuse after CO2 capture from flue gases by an alkaline solution (i.e., NaOH). In this study, the biomimetic aquaporin Inside™ membrane AIM60 was employed to enhance water removal, facilit......Membrane assisted crystallization (MACr) offers an innovative platform for crystallizing Na2CO3, allowing its reuse after CO2 capture from flue gases by an alkaline solution (i.e., NaOH). In this study, the biomimetic aquaporin Inside™ membrane AIM60 was employed to enhance water removal......, a proper control of the supersaturation level induces crystallization of Na2CO3·10H2O crystals with a purity of 99.94%. Hence, the aquaporin Inside™ FO membrane may be a promising alternative to existing methods for Na2CO3 crystallization for its application in a CO2 capture scenario....

  3. Structure, flame retarding and smoke suppressing properties of Zn-Mg-Al-CO3 layered double hydroxides

    Institute of Scientific and Technical Information of China (English)

    SHI Ling; LI Dianqing; LI Sufeng; WANG Jianrong; Evans D. G.; DUAN Xue

    2005-01-01

    Zn-Mg-Al-CO3 layered double hydroxides (LDHs) have been synthesized by a new method involving separate nucleation and aging steps. The Zn-Mg-Al-CO3 LDHs were characterized by XRD, FT-IR, ICP and TG-DTA. The limiting oxygen index and smoke density of composites of the LDHs with EVA-28 were determined. Incorporation of Zn2+ in the layers of the LDHs was found promoting material charring and smoke suppression. The mechanism of flame retardation and smoke suppression is discussed. The results show that Zn-Mg-Al-CO3 LDHs have better flame retarding and smoke suppressing effects than Mg-Al-CO3 LDHs.

  4. Physical properties and electronic band structure of noncentrosymmetric Th7Co3 superconductor

    Science.gov (United States)

    Sahakyan, M.; Tran, V. H.

    2016-05-01

    The physical properties of the noncentrosymmetric superconductor Th7Co3 have been investigated by means of ac-magnetic susceptibility, magnetization, specific heat, electrical resistivity, magnetoresistance and Hall effect measurements. From these data it is established that Th7Co3 is a dirty type-II superconductor with {{T}\\text{c}}=1.8+/- 0.02 K, Hc2\\text{orb}text{kOe}c2p and moderate electron-phonon coupling {λ\\text{el-\\text{ph}}}=0.56 . Some evidences for anisotropic superconducting gap are found, including e.g. reduced specific heat jump (Δ {{C}p}/γ {{T}\\text{c}}=1.01 ) at T c, diminished superconducting energy gap ({{Δ }0}/{{k}\\text{B}}{{T}\\text{c}}=2.17 ) as compared to the BCS values, power law field dependence of the Sommerfeld coefficient at 0.4 K ({{C}p}/T\\propto {{H}0.6} ), and a concave curvature of the {{H}c2}≤ft({{T}\\text{c}}\\right) line. The magnitudes of the thermodynamic critical field and the energy gap are consistent with mean-squared anisotropy parameter ˜ 0.23 . The electronic specific heat in the superconducting state is reasonably fitted to an oblate spheroidal gap model. Calculations of scalar relativistic and fully relativistic electronic band structures reveal considerable differences in the degenerate structure, resulting from asymmetric spin-orbit coupling (ASOC). A large splitting energy of spin-up spin-down bands at the Fermi level E F, Δ {{E}\\text{ASOC}}˜ 100 meV is observed and a sizeable ratio Δ {{E}\\text{ASOC}}/{{k}\\text{B}}{{T}\\text{c}}˜ 640 could classify the studied compound into the class of noncentrosymmetric superconductors with strong ASOC. The noncentrosymmetry of the crystal structure and the atomic relativistic effects are both responsible for an importance of ASOC in Th7Co3. The calculated results for the density of states show a Van Hove singularity just below E F and dominant role of the 6d electrons of Th to the superconductivity.

  5. THE ORIENTATION OF CaCO3 ARAGONITE CRYSTALS FROM SEVERAL ORGANISMS%几种生物CaCO3霰石结晶的取向性

    Institute of Scientific and Technical Information of China (English)

    蒋新农; 李敬之; 徐学红

    2001-01-01

    The CaCO3 crystals are widely distributed in organisms. Thecalcite, aragonite and vaterite are the main crystal polymorphisms of CaCO3. In this paper, CaCO3 crystals were obtained from the nacreous layers of Hyriopsis cumingii Lea and Pinctada martensii Dunker, the internal shell of a cuttlefish and the otolith of Pseudosciaena crocea. X-ray diffraction measurement was used to analyze the crystal orientation of CaCO3 crystals: The results showed that each kind of natural CaCO3 crystal has an orientation on specific plane. In detail, the crystal orientations of the nacreous layers are higher than the internal shell, and the orientation of the otolith is the lowest. Except the nacreous layers of Pinctada martensii, whose highest peak is on the crystal plane (312), all the other three natural samples have the highest peak on the crystal plane (012). As to ground CaCO3 crystals, the differences between their corresponding d values are very small, so each ground sample has the CaCO3 aragonite structure characterized by the JCPDS card (5-0453).%CaCO3结晶广泛分布于生物界,其主要结晶形式为方解石、霰石及球霰石。用X-射线衍射法对三角帆蚌及合浦珍珠母贝的珍珠层、墨鱼骨和大黄鱼耳石的CaCO3结晶进行测定,发现各样品均有一定取向性,以三角帆蚌和合浦珍珠母贝珍珠层的取向性为最强,墨鱼骨的取向性次之,大黄鱼耳石的取向性最小,以上材料粉末样的衍射分析表明,各样品对应d值间差异极小,均为X射线衍射卡(5-0453)所表征的CaCO3霰石结构。

  6. Influence of precipitated calcium carbonate (CaCO3) on shiitake (Lentinula edodes) yield and mushroom size.

    Science.gov (United States)

    Royse, Daniel J; Sanchez-Vazquez, Jose E

    2003-11-01

    Synthetic substrate consisting of oak sawdust (50%), white millet (28%), winter rye (11%) and soft red wheat bran (11%) was non-supplemented or supplemented with 0.2%, 0.4% or 0.6% (dry weight basis) precipitated calcium carbonate (CaCO(3)). Shiitake (Lentinula edodes) was grown in two crops to determine the effect of three CaCO(3) levels on mushroom yield and size. Yields and biological efficiencies (averages for two crops) from substrates non-supplemented with CaCO(3) were lower by 14.1%, 18.4% and 24.9% compared to treatments supplemented with 0.2%, 0.4% and 0.6% CaCO(3), respectively. Mushroom size (weight) was larger with non-supplemented substrate (16.8 g) compared to substrate supplemented with 0.6% CaCO(3) (15.1 g). However, mushroom production was more consistent from crop to crop when 0.6% CaCO(3) was added to substrate.

  7. Graphene-Embedded Co3O4 Rose-Spheres for Enhanced Performance in Lithium Ion Batteries.

    Science.gov (United States)

    Jing, Mingjun; Zhou, Minjie; Li, Gangyong; Chen, Zhengu; Xu, Wenyuan; Chen, Xiaobo; Hou, Zhaohui

    2017-03-22

    Co3O4 has been widely studied as a promising candidate as an anode material for lithium ion batteries. However, the huge volume change and structural strain associated with the Li(+) insertion and extraction process leads to the pulverization and deterioration of the electrode, resulting in a poor performance in lithium ion batteries. In this paper, Co3O4 rose-spheres obtained via hydrothermal technique are successfully embedded in graphene through an electrostatic self-assembly process. Graphene-embedded Co3O4 rose-spheres (G-Co3O4) show a high reversible capacity, a good cyclic performance, and an excellent rate capability, e.g., a stable capacity of 1110.8 mAh g(-1) at 90 mA g(-1) (0.1 C), and a reversible capacity of 462.3 mAh g(-1) at 1800 mA g(-1) (2 C), benefitted from the novel architecture of graphene-embedded Co3O4 rose-spheres. This work has demonstrated a feasible strategy to improve the performance of Co3O4 for lithium-ion battery application.

  8. Co3O4 Electrode Prepared by Using Metal-Organic Framework as a Host for Supercapacitors

    Directory of Open Access Journals (Sweden)

    Jiaqiang Jiang

    2015-01-01

    Full Text Available Co3O4 nanoparticles were prepared from cobalt nitrate that was accommodated in the pores of a metal-organic framework (MOF ZIF-8 (Zn(MeIM2, MeIM = 2-methylimidazole by using a simple liquid-phase method. Analysis by scanning electron microscopy (SEM and transmission electron microscopy (TEM showed that the obtained Co3O4 was composed of separate nanoparticles with a mean size of 30 nm. The obtained Co3O4 nanoparticles exhibited superior electrochemical property. Co3O4 electrode exhibited a maximum specific capacitance of 189.1 F g−1 at the specific current of 0.2 A g−1. Meanwhile, the Co3O4 electrode possessed the high specific capacitance retention ratio at the current density ranging from 0.2 to 1.0 A g−1, thereby indicating that Co3O4 electrode suited high-rate charge/discharge.

  9. Fabrication and characterization of a novel hydrophobic CaCO3 grafted by hydroxylated poly(vinyl chloride) chains

    Science.gov (United States)

    Bao, Lixia; Yang, Simei; Luo, Xin; Lei, Jingxin; Cao, Qiue; Wang, Jiliang

    2015-12-01

    The hydroxylated PVC (PVC-OH) was successfully synthesized by a suspension polymerization of vinyl chloride (VC), butyl acrylate (BA) and hydroxyethyl acrylate (HEA). Novel hydrophobic CaCO3 was then prepared by a urethane formation reaction between methylene diphenyl diisocyanate (MDI) and the sbnd OH groups both in the PVC-OH chains and on the surface of pristine CaCO3 particles. The effect of the PVC-OH content on the grafting ratio of treated CaCO3 particles was extensively investigated. Combining the result of Fourier transform infrared (FTIR) with that of water contact angle, it can be concluded that the hydrophobicity of CaCO3 had been efficiently improved by the PVC-OH segments grafted on the surface of CaCO3 particles. X-ray diffraction (XRD), thermal gravity analysis (TGA), scanning electron microscope (SEM) and transmission electron microscope (TEM) were also used to study crystalline behaviors, thermal stability and surface morphology of the modified CaCO3 particles, respectively. The change of specific surface area implying surface modification was investigated as well.

  10. The hybridization of Ag2CO3 rods with g-C3N4 sheets with improved photocatalytic activity

    Directory of Open Access Journals (Sweden)

    Konglin Wu

    2015-09-01

    Full Text Available A series of graphitic carbon nitride/silver carbonate (g-C3N4/Ag2CO3 rod-like composites with different weight contents of g-C3N4 have been prepared by a facile precipitation method. The g-C3N4/Ag2CO3 rod-like composites exhibited higher photocatalytic activity than pure Ag2CO3 toward degradation of rhodamine B (RhB and methylene blue (MB under visible-light irradiation. The photocatalytic reaction follows a pseudo-first-order reaction and the rate constants for the degradation of RhB and MB by 3.5% g-C3N4/Ag2CO3 are about 2 times and 1.7 times that of pure Ag2CO3, respectively. A possible photocatalytic mechanism was proposed based on the photoluminescence (PL spectra and a series of radical trapping experimental analyses. The remarkably improved photocatalytic performance should be ascribed to the heterostructure between Ag2CO3 and g-C3N4, which greatly promoted the photoinduced charge transfer and inhibited the recombination of electrons and holes.

  11. Synthesis of Co3O4/NiO nanofilms and their enhanced electrochemical performance for supercapacitor application

    Science.gov (United States)

    Zuo, Yong; Ni, Jing-Jing; Song, Ji-Ming; Niu, He-Lin; Mao, Chang-Jie; Zhang, Sheng-Yi; Shen, Yu-Hua

    2016-05-01

    Transition metallic oxides have attracted considerable attention for supercapacitor applications because of their superior electrochemical performance at relatively low cost. Co3O4/NiO nanofilms were successfully prepared by calcination of precursor α-Co(OH)2/α-Ni(OH)2. XRD, XPS, SEM and TEM techniques were used to characterize the composition and morphology of as-prepared samples. The results demonstrated that Co3O4/NiO nanofilms presented graphene-like morphology with shrinkage and wrinkles. The Brunauer-Emmett-Teller (BET) measurement showed that specific surface area of Co3O4/NiO was 176.5 m2/g. Electrochemical properties tests indicated that the Co3O4/NiO nanofilms had a higher specific capacitance and better rate capability than that of precursor α-Co(OH)2/α-Ni(OH)2 at high current density. As to the cycling performance, the specific capacitance of Co3O4/NiO electrode would first increase from 556 F/g to 710 F/g quickly at 2 A/g after 80 cycles and then remained stable. Therefore, compared with that of precursor α-Co(OH)2/α-Ni(OH)2, the capacitance performance of as-prepared Co3O4/NiO nanofilms was improved after calcination. The possible reason for the enhancement of capacitance performance was discussed.

  12. Effects of CaCO3 treatment on the morphology, crystallinity, rheology and hydrolysis of gelatinized maize starch dispersions.

    Science.gov (United States)

    Garcia-Diaz, S; Hernandez-Jaimes, C; Escalona-Buendia, H B; Bello-Perez, L A; Vernon-Carter, E J; Alvarez-Ramirez, J

    2016-09-15

    Using calcium salts instead of lime allows for an ecological nixtamalization of maize grains, where the negative contamination impact of the traditional lime nixtamalization is reduced. This work assessed the effects of calcium carbonate (0.0-2.0%w/w CaCO3) on the morphology, crystallinity, rheology and hydrolysis of gelatinized maize starch dispersions (GMSD). Microscopy analysis showed that CaCO3 changed the morphology of insoluble remnants (ghosts) and decreased the degree of syneresis. Analysis of particle size distribution showed a slight shift to smaller sizes as the CaCO3 was increased. Also, X-ray patterns indicated that crystallinity achieved a minimum value at CaCO3 concentration in the range of 1%w/w. GMSD with higher CaCO3 concentrations exhibited higher thixotropy area and complex viscoelastic behavior that was frequency dependent. A possible mechanism involved in the starch chain modification by CaCO3 is that starch may act as a weak acid ion exchanger capable of exchanging alcoholic group protons for cations (Ca(+2)).

  13. Enhanced Photoreduction Activity of Carbon Dioxide over Co3O4/CeO2 Catalysts under Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    Ying Huang

    2015-01-01

    Full Text Available A series of new two semiconductor catalysts, Co3O4/CeO2, were prepared by glycine-nitrate combustion method for photocatalytic reduction of carbon dioxide to produce methanol and ethanol under visible light (λ>400 nm irradiation. The catalysts were characterized by BET, UV-vis spectra, XRD, SEM, PL, and XPS and the results indicated that the catalyst with 5 wt.% of Co3O4 has the highest yield among all kinds of tests with the methanol yield of 1.52 μmol·g−1·h−1 and the ethanol yield of 4.75 μmol·g−1·h−1, which are about 2.34 and 1.71 times as large as those of CeO2. However, methanol and ethanol can hardly be detected for Co3O4 under the same condition because of its too narrow band gap. The improvement of the photoreduction activity of Co3O4 doped CeO2 was caused by the separation of electron-hole pairs of Co3O4/CeO2 and charge transfer between Co3O4 and CeO2, mimicking the Z-scheme in photosynthesis.

  14. Hydrogen Peroxide Sensor Based on Horseradish Peroxidase Combined with CaCO3 Microspheres and Gold Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    ZHENG Li; JIANG Feng-hua; MA Guang-ran; ZHUANG Qian-fen; LI Feng

    2011-01-01

    Direct electrochemistry and electrocatalysis of horseradish peroxidase(HRP) were achieved by entrapping the enzyme between CaCO3 microspheres and gold nanoparticles through forming sandwich configuration (CaCO3-HRP-AuNPs).Polyanion,poly(styrene sulfonate)(PSS),was hybrid with CaCO3 microspheres to increase the surface negative charges for binding with HRP through electrostatic interaction.After the bioconjugate CaCO3 PSS-HRP was entrapped in chitosan based sol-gel(CS-GPTMS) film,HRP was encapsulated by in situ formation of an outer layer of AuNPs through electrochemical reduction of HAuCl4.The composite film containing AuNPs,CaCO3-PSS-HRP bioconjugates and CS-GPTMS can provide favorable microenvironment for HRP to perform direct electron transfer at glassy carbon electrode(GCE).HRP retained its bioelectrocatalytic activity and lead to sensitive and fast amperometric response for the determination of H2O2.H2O2 could be detected in a very wide linear range from 5.0× 10-6 mol/L to 7.1× 10-2 mol/L.The sandwich configuration of CaCO3-biomolecules-AuNPs could serve as a versatile platform for enzyme immobilization and biosensing.

  15. Catalytic oxidation of benzene over nanostructured porous Co3O4-CeO2 composite catalysts

    Institute of Scientific and Technical Information of China (English)

    Chunyan Ma; Zhen Mu; Chi He; Peng Li; Jinjun Li; Zhengping Hao

    2011-01-01

    Mesostructured Co3O4-CeO2 composite was found to be an effective catalytic material for the complete oxidation of benzene.The Co3O4-CeO2 catalysts with different Co/Ce ratios (mol/mol) were prepared via the nanocasting method and the mesostructure was replicated from two-dimensional (2D) hexagonal SBA-15 and three-dimensional (3D) cubic KIT-6 silicas,respectively.All the obtained Co3O4-CeO2 catalysts exhibited the similar symmetry with the parent silicas and well ordered mesostructures.The Co3O4-CeO2 catalysts with 2D mesostructure showed lower catalytic activities than the corresponding 3D materials.The Co3O4-CeO2 catalyst nanocasted from KIT-6 and with the Co/Ce ratio of 16/1 possessed the best catalytic benzene oxidation activity due to larger quantities of surface hydroxyl groups and surface oxygenated species.The mesostructured Co3O4-CeO2 material thus shows great potential as a promising eco-environmental catalyst for benzene effective elimination.

  16. Photoluminescence study of Tb3+ doped CaCO3 synthesized by solid state metathesis

    Science.gov (United States)

    Muke, A. M.; Ugemuge, N. S.; Moharil, S. V.

    2016-05-01

    Conventional solid-state reaction or simple solution precipitation techniques suffer from several limitations, i.e. a high processing temperature, relatively high preparation cost and more time of preparation, highly complicated synthesis, in-stoichiometric compositions and poor crystallinity. Preparation of inorganic phosphors by microwave assisted Solid state metathesis is one of the superior methods of synthesis. Time duration required for synthesis by microwave assisted synthesis is relatively low. The required reaction temperature can be attempted using domestic microwave oven with consumption of relatively low energy. CaCO3 is one of the most abundant biological minerals in nature and has found many important applications in industry, such as pigments, paper makings, plastics, rubbers, and so on.

  17. Production of Poly(3-Hydroxybutyrate-co-3-Hydroxyhexanoate) by Aeromonas hydrophila and Recombinant Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    丘远征; 刘力平; 陈国强

    2003-01-01

    Aeromonas hydrophila (A.hydrophila) 4AK4 produced poly(3-hydroxybutyrate-co-3- hydroxyhexanoate) (PHBHHx) with an almost constant 3-hydroxyhexanoate (3HHx) content of 10%-15% from lauric acid and/or soybean oil.Both A.hydrophila 4AK4 and recombinant Escherichia coli (E.coli) JMU193 (pBH32) produced PHBHHx with controllable 3HHx content when fed lauric acid and another co-substrate.With glucose or gluconate as the co-substrate, the 3HHx content in the copolyester produced by A.hydrophila 4AK4 was reduced slightly from 12% to 9%.However, the 3HHx content in the copolyester produced by E.coli JMU193 (pBH32) was significantly reduced from 9% to 2% with fructose as the co-substrate.These results show that regulation of 3HHx content in PHBHHx can be achieved using genetically engineered E.coli.

  18. Magnetic phase diagram of the antiferromagnetic cobalt tellurate Co3TeO6

    Science.gov (United States)

    Her, J. L.; Chou, C. C.; Matsuda, Y. H.; Kindo, K.; Berger, H.; Tseng, K. F.; Wang, C. W.; Li, W. H.; Yang, H. D.

    2011-12-01

    In this study, we measured the temperature-dependent magnetic susceptibility [χ(T)], ac magnetic susceptibility [χac(T)], specific heat [Cp(T)], and high-field magnetization [M(H)] of a newly synthesized single-crystalline material, Co3TeO6. Two transitions were observed in χ(T) and Cp(T) curves at values of TN1 and TN2 of approximately 26 and 18 K (H = 0), respectively. The high-field M(H) curves exhibited strong magnetic anisotropy and several field-induced transitions, suggesting that the magnetic ground state was complicated. Large spin-lattice coupling was evident by the large hysteresis in the M(H) curves and through analysis of the specific heat data. We propose herein an H-T phase diagram that is consistent with our experimental findings.

  19. Crystal structure and magnetization of a Co3B2O6 single crystal

    Science.gov (United States)

    Kazak, N. V.; Platunov, M. S.; Ivanova, N. B.; Knyazev, Yu. V.; Bezmaternykh, L. N.; Eremin, E. V.; Vasil'ev, A. D.; Bayukov, O. A.; Ovchinnikov, S. G.; Velikanov, D. A.; Zubavichus, Ya. V.

    2013-07-01

    The crystal structure and magnetic properties of Co3B2O6 single crystals are studied. Orthorhombic symmetry with space group Pnnm is detected at room temperature. The measurements of static magnetization and dynamic magnetic susceptibility reveal two magnetic anomalies at T 1 = 33 K and T 2 = 10 K and an easy-axis magnetic anisotropy. The effective magnetic moment indicates a high-spin state of the Co2+ ion. A spin-flop transition is found at low temperatures and H sf = 23 kOe. EXAFS spectra of the K-edge absorption of Co are recorded at various temperatures, the temperature-induced changes in the parameters of the local environment of cobalt are analyzed, and the effective Co-Co and Co-O distances are determined. The magnetic interactions in the crystal are analyzed in terms of an indirect coupling model.

  20. Thermal depolymerization mechanisms of poly (3-hydroxybutyrate-co-3-hydroxyvalerate)

    Institute of Scientific and Technical Information of China (English)

    Hengxue Xiang; Xiaoshuang Wen; Xiaohui Miu; Yan Li; Zhe Zhou; Meifang Zhu

    2016-01-01

    Thermal degradation processes and decomposition mechanisms of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) were investigated by using thermal gravity analysis(TGA), Gel permeation chromatography (GPC), elemental analyzer, pyrolysis-gas chromatography-mass spectrometry (PyGC-MS) and 1H nuclear magnetic resonance (1H NMR). The degradation activation energy was calculated via the dependence of residual mass on isothermal temperature. 1H NMR and PyGC-MS were used to investigate the chemical structure and component proportion of volatile gases and degradation residues which were produced by thermal decomposition, and to infer the process of macromolecular chain scission. Besides, the influence of the factors, such as outfield atmosphere, residual metal ions, on the degradation behaviors of PHBV was also studied. Finally, the PHBV thermal decomposition mechanisms were speculated on the basis of the degradation behaviors of molecular and chemical structure.

  1. CIRCUMSTELLAR MAGNETITE FROM THE LAP 031117 CO3.0 CHONDRITE

    Energy Technology Data Exchange (ETDEWEB)

    Zega, Thomas J. [Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd, Tucson, AZ 85721-0092 (United States); Haenecour, Pierre; Floss, Christine [Laboratory for Space Sciences and Physics Department, Washington University, One Brookings Drive, Campus Box 1105, St. Louis, MO 63130 (United States); Stroud, Rhonda M., E-mail: tzega@lpl.arizona.edu [Materials Science and Technology Division, Code 6366, Naval Research Laboratory, 4555 Overlook Ave, SW Washington, DC 20375 (United States)

    2015-07-20

    We report the first microstructural confirmation of circumstellar magnetite, identified in a petrographic thin section of the LaPaz Icefield 031117 CO3.0 chondrite. The O-isotopic composition of the grain indicates an origin in a low-mass (∼2.2 M{sub ⊙}), approximately solar metallicity red/asymptotic giant branch (RGB/AGB) star undergoing first dredge-up. The magnetite is a single crystal measuring 750 × 670 nm, is free of defects, and is stoichiometric Fe{sub 3}O{sub 4}. We hypothesize that the magnetite formed via oxidation of previously condensed Fe dust within the circumstellar envelope of its progenitor star. Using an empirically derived rate constant for this reaction, we calculate that such oxidation could have occurred over timescales ranging from approximately ∼9000–500,000 years. This timescale is within the lifetime of estimates for dust condensation within RGB/AGB stars.

  2. Synthesis, characterization, scale-up and catalytic behaviour of Co3O4 nanoparticles

    Indian Academy of Sciences (India)

    Manpreet Singh; N K Ralhan; Sukhdeep Singh

    2015-04-01

    Highly uniform cobalt oxide (Co3O4) nanoparticles were synthesized via thermal decomposition of cobalt hydroxy carbonates with particle size around 16 ± 1 nm. The process gives reproducible results in batches of 1–5 kg. The particles show good catalytic activity for the oxidation of oxalic acid and benzaldehyde under mild temperature conditions. The characterization was performed by X-ray diffractometry (XRD), Transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR) spectrum and Nuclear magnetic resonance (NMR). The XRD measurements show cubic spinel phase and Debye–Scherrer relation was used to measure average particle size. The convenience of the production of catalyst can be exploited for its large-scale production and use in laboratories, R&Ds and industries.

  3. Thermal depolymerization mechanisms of poly(3-hydroxybutyrate-co-3-hydroxyvalerate

    Directory of Open Access Journals (Sweden)

    Hengxue Xiang

    2016-02-01

    Full Text Available Thermal degradation processes and decomposition mechanisms of poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV were investigated by using thermal gravity analysis(TGA, Gel permeation chromatography (GPC, elemental analyzer, pyrolysis-gas chromatography-mass spectrometry (PyGC-MS and 1H nuclear magnetic resonance (1H NMR. The degradation activation energy was calculated via the dependence of residual mass on isothermal temperature. 1H NMR and PyGC-MS were used to investigate the chemical structure and component proportion of volatile gases and degradation residues which were produced by thermal decomposition, and to infer the process of macromolecular chain scission. Besides, the influence of the factors, such as outfield atmosphere, residual metal ions, on the degradation behaviors of PHBV was also studied. Finally, the PHBV thermal decomposition mechanisms were speculated on the basis of the degradation behaviors of molecular and chemical structure.

  4. Magnetic Properties of the Dy1-xUxCo3 System

    Science.gov (United States)

    Lupşa, Ileana; Petrişor, T.; Balasz-Mureşan, I.

    The magnetic properties of Dy1-xUxCo3 system were investigated in the 4.3-1150 K temperature range and magnetic field up to 120 kOe. The crystalline structure is rhombohedral of PuNi3 type. For x≤0.8, the samples exhibit a ferrimagnetic behavior. The uranium substitution for dysprosium leads to the decreasing of the exchange field and the reducing of the magnetization and the transition temperatures. The Co mean moments (1.9μB/Co for x=0) opposite to the dysprosium ones and the mean effective Co moments (3.75μB/Co for x=0) are gradually decreasing as Dy is replaced by uranium.

  5. Thermal conductivity of the diamond-chain compound Cu3(CO3)2(OH)2

    Science.gov (United States)

    Wu, J. C.; Song, J. D.; Zhao, Z. Y.; Shi, J.; Xu, H. S.; Zhao, J. Y.; Liu, X. G.; Zhao, X.; Sun, X. F.

    2016-02-01

    Thermal conductivity (κ) of a distorted spin diamond-chain system, Cu3(CO3)2(OH)2, is studied at low temperatures down to 0.3 K and in magnetic fields up to 14 T. In zero field, the κ (T) curve with heat current along the chain direction has very small magnitudes and shows a pronounced three-peak structure. The magnetic fields along and perpendicular to the chains change the κ strongly in a way having good correspondence to the changes of magnetic specific heat in fields. The data analysis based on the Debye model for phononic thermal conductivity indicates that the heat transport is due to phonons and the three-peak structure is caused by two resonant scattering processes by the magnetic excitations. In particular, the spin excitations of the chain subsystem are strongly scattering phonons rather than transporting heat.

  6. Effect of precipitation procedure and detection technique on particle size distribution of CaCO 3

    Science.gov (United States)

    Martos, C.; Coto, B.; Peña, J. L.; Rodríguez, R.; Merino-Garcia, D.; Pastor, G.

    2010-09-01

    The deposition of inorganic salts ("scales") such as calcium carbonate is an important flow assurance problem during crude oil production. The knowledge of the features of the precipitated solids, mainly the particle size and morphology, is crucial to understand the nature of the solids and to avoid or reduce the effect of their deposition. For instance, the use of additives is one of the most usual procedures to mitigate this problem. Additives interact with scale-forming substances either by increasing the induction time, or by inhibiting crystal growth, changing the morphology of solids. In this work, CaCO 3 was precipitated by two different experimental methods: by mixing sodium carbonate and calcium chloride at 25 °C (method 1), and by changing the pH (method 2). Precipitated solids were analyzed by means of the following techniques: laser diffraction (LD), focused-beam reflectance measurement (FBRM), scanning electron microscopy (SEM), and X-ray diffraction (XRD), in order to select a method for the determination of particle size of solids similar to scales, in order to study these deposits at the beginning of their formation and to evaluate the effect of additives in the scales particle size. Results were compared to those of scale deposits extracted from crude oil pipelines. SEM and XRD characterization showed that both the precipitation methods lead to calcium carbonate as a mixture of calcite, aragonite and vaterite, with rhombohedral morphology for method 1 and spherical for method 2. The effects of temperature, kinetics and Mg 2+ presence in the morphology of CaCO 3 were evaluated. Thus, the solids obtained by static bottle test and real scales are mainly formed by long needle-shaped aragonite. The comparison of the several particle size characterization methods determinates that an LD is a fast and sensitive technique for spherical and non-spherical solids, and it is a convenient technique for the analysis of scales extracted from oil pipelines.

  7. LPG and NH3 sensing characteristics of DC electrochemically deposited Co3O4 films

    Science.gov (United States)

    Shelke, P. N.; Khollam, Y. B.; Gunjal, S. D.; Koinkar, P. M.; Jadkar, S. R.; Mohite, K. C.

    2015-03-01

    Present communication reports the LPG and NH3 sensing properties of Co3O4 films prepared on throughly cleaned stainless steel (SS) and copper (CU) substrates by using DC electrochemical deposition method followed by air annealing at 350°C/2 h. The resultant films are characterized by using X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). The LPG and NH3 gas sensing properties of these films are measured at room temperature (RT) by using static gas sensing system at different concentrations of test gas ranging from 25 ppm to 350 ppm. The XRD and Raman spectroscopy studies clearly indicated the formation of pure cubic spinel Co3O4 in all films. The LPG and NH3 gas sensing properties of films showed (i) the increase in sensitivity factor (S.F.) with gas concentrations and (ii) more sensibility to LPG as compared to NH3 gas. In case of NH3 gas (conc. 150 ppm) and LPG gas (conc. 60 ppm) sensing, the maximum S.F. = 270 and 258 are found for the films deposited on CU substrates, respectively. For all films, the response time (3-5 min.) is found to be much higher than the recovery time (30-50 sec). For all films, the response and recovery time are found to be higher for LPG as compared to NH3 gas. Further, repeatability-reproducibility in gas sensing properties is clearly noted by analysis of data for number of cycles recorded for all films from different set of depositions.

  8. The Influence of Vibration on CaCO3 Scale Formation in Piping System

    Directory of Open Access Journals (Sweden)

    Mangestiyono W.

    2016-01-01

    Full Text Available Carbonate scale is a common problem found in a piping system of industrial process. The presence of mechanical equipment such as turbine, compressor, blower, mixer and extruder produce a mechanical vibration on the piping system which is placed near these equipments. The influence of vibration on the CaCO3 scale formation in the piping system was experimentally investigated in the present study. The aim of the research was to understand the effect of vibration on the kinetics, deposition rates and the crystals formation in the synthetic solution. The solution was prepared using CaCl2 and Na2CO3 for concentration of calcium of 3.500 ppm, while the induction time, deposition rate, crystal growth were investigated at temperature of 25°C. In generating the vibration force, the mechanical equipment consisting of electrical motor, crankshaft, connecting rod and a vibration table were employed, including four coupons inside the pipe for investigating the scale formed. Frequency of the vibration was set at 0.00, 1.00 Hz and 2.00 Hz, respectively. A dosing pump with two inlets and two outlets was used to circulate the solutions at flowrate of 30 ml/min from each vessel to the coupons. After running for three hours, the induction time was recorded at 17; 10 and 8 minute with vibration frequency of 0.00; 1.00 and 2.00 Hz, respectively. The scale formed was then characterized using SEM/EDX for crystal morphology and elemental analysis. The results show that the deposition rates were 0.9457 and 3.3441 gram/h for the frequency of 1.00 and 2.00 Hz. The carbonate crystals found in coupon and filter were vaterite.

  9. Preparation of PVC/ (VC/BA)/nano-CaCO3 Composite and Its Mechanical Properties%PVC/(VC/BA)/纳米CaCO3复合材料的研制及其力学性能研究

    Institute of Scientific and Technical Information of China (English)

    王士财; 李宝霞; 楼涛; 张晓东

    2007-01-01

    通过对纳米碳酸钙(nano-CaCO3)表面处理及其对聚氯乙烯(PVC)、氯乙烯-丙烯酸丁酯共聚物(VC/BA)、nano-CaCO3三元复合体系加工工艺的考察,研制了PVC/(VC/BA)/nano-CaCO3复合材料,并对其力学性能进行了研究.结果表明:以nano-CaCO3与VC/BA共聚物先制成复合母粒,再与PVC进行共混的二次分散成型工艺,比传统的将三者直接进行共混的一次分散成型工艺更有利于纳米粒子在基体中的分散,所制材料的力学性能更优.当复合母粒中VC/BA与nano-CaCO3的比例为2∶3时,材料的力学性能最佳,nano-CaCO3和VC/BA能协同增韧PVC,并且nano-CaCO3对材料具有补强作用,使材料在强度保持基本不变的情况下冲击性能得到大幅度提高,当PVC和复合母粒质量比为100∶20时,材料的冲击强度达到49.5kJ/m,是纯PVC(PVC的冲击强度为4.9kJ/m)的10倍,拉伸强度仍高达51.0MPa.

  10. CaCO3 dissolution by holothurians (sea cucumber): a case study from One Tree Reef, Great Barrier Reef

    Science.gov (United States)

    Schneider, K.; Silverman, J.; Kravitz, B.; Woolsey, E.; Eriksson, H.; Schneider-Mor, A.; Barbosa, S.; Rivlin, T.; Byrne, M.; Caldeira, K.

    2012-12-01

    Holothurians (sea cucumbers) are among the largest and most important deposit feeder in coral reefs. They play a role in nutrient and CaCO3 cycling within the reef structure. As a result of their digestive process they secrete alkalinity due to CaCO3 dissolution and organic matter degradation forming CO2 and ammonium. In a survey at station DK13 on One Three Reef we found that the population density of holothurians was > 1 individual m-2. The dominant sea cucumber species Holothuria leucospilota was collected from DK13. The increase in alkalinity due to CaCO3 dissolution in aquaria incubations was measured to be 47±7 μmol kg-1 in average per individual. Combining this dissolution rate with the sea cucumbers concentrations at DK13 suggest that they may account for a dissolution rate of 34.9±17.8 mmol m-2 day-1, which is equivalent to about half of night time community dissolution measured in DK13. This indicates that in reefs where the sea cucumber population is healthy and protected from fishing they can be locally important in the CaCO3 cycle. Preliminary result suggests that the CaCO3 dissolution rates are not affected by the chemistry of the sea water they are incubated in. Measurements of the empty digestive track volume of two sea cucumbers H. atra and Stichopus herrmanni were 36 ± 4 ml and 151 ± 14 ml, respectively. Based on these measurements it is estimated that these species process 19 ± 2kg and 80 ± 7kg CaCO3 sand yr-1 per individual, respectively. The annual dissolution rates of H. atra and S. herrmanni are 6.5±1.9g and 9.6±1.4g, respectively, suggest that 0.05±0.02% and 0.1±0.02% of the CaCO3 processed through their gut annually is dissolved. During the incubations the CaCO3 dissolution was 0.07±0.01%, 0.04±0.01% and 0.21±0.05% of the fecal casts for H. atra, H. leucospilota and S. herrmanni, respectively. Our result that the primary parameter determining the CaCO3 dissolution by sea cucumber is the amount of carbonate send in their gut

  11. Co3O4电化学电容电极材料的制备及性能研究%Preparation and performance of Co3O4 as electrode material for electrochemical capacitor

    Institute of Scientific and Technical Information of China (English)

    王兴磊; 何晓燕; 欧阳艳

    2012-01-01

    The Co304 materials have been synthesized via hydrothermal method, using sucrose as cobal-tous nitrate [ Co ( N03 )3 ], hexamethylenetetramine ( C6H12 N4 ) and ammonium acid carbonate (NH4HCO3). The physical properties of CO3O4 powders were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM). The electrochemical properties of CO3O4 powders were characterized by cyclic voltammogram and galvanostatic charge/discharge measurements in 6mol ? L" KOH electrolyte with the potential range from 0.0 to 0.4V (vs. SCE). The results demonstrated that the CO3O4 by C6H,2C4 for the precipitation agent had a good stability performance. Its specific capacitance as single electrode was up to 239 F ? G"1, that is 1. 57 times of the CO3O4 specific capacitance by NH4HCO3 for the precipitation agent. It is indicated that the CO3O4 were prepared by C6Hl2N4 as precipitating agent has good electrochemical capacitance performance.%利用水热法,以硝酸钴为原料,分别以碳酸氢铵、六次甲基四胺为沉淀剂,制备了Co3O4.借助X射线衍射、扫描电子显微镜手段对样品进行表征.以六次甲基四胺为沉淀剂制得的Co3O4,在6 mol·L-1KOH水溶液中,电位窗口为0~0.4V内,通过循环伏安和恒流充放电测试,显示该材料制备的电极具有良好的电容行为.充放电流在为5mA时,单电极的比容量达到239 F·g-1,是以碳酸氢铵为沉淀剂制得的Co3O4电极的1.57倍,说明以六次甲基四胺为沉淀剂制备的Co3O4具有较好的电化学电容性能.

  12. Investigation of formaldehyde oxidation over Co3O4-Ce2 and Au/Co3O4-CeO2 catalysts at room temperature: effective removal and determination of reaction mechanism.

    Science.gov (United States)

    Ma, Chunyan; Wang, Donghui; Xue, Wenjuan; Dou, Baojuan; Wang, Hailin; Hao, Zhengping

    2011-04-15

    Formaldehyde is regarded as the major indoor pollutant emitted from widely used building and decorative materials in airtight buildings, which should be eliminated under indoor environmental conditions. We report here catalytic oxidation process of formaldehyde over mesoporous Co(3)O(4), Co(3)O(4)-CeO(2), Au/Co(3)O(4), and Au/Co(3)O(4)-CeO(2) catalysts and their excellent catalytic performances at room temperature. These catalysts were prepared by a "nanocasting" method with the mesostructure generated from SBA-15 silica with 2D structure. The adsorbed surface species in the formaldehyde oxidation process are analyzed, and some key steps in the oxidation pathway, active sites, and intermediate species are proposed. Among the detected species, some kinds of formate species formed on the catalysts were indentified as intermediates, which further transformed into bicarbonate or carbonate and which decomposed to carbon dioxide. The role of the mesoporous Co(3)O(4) and the gold nanoparticles in the mechanism are also revealed.

  13. Relationship between the Structure and Impact Property of Nano-CaCO3/PVC Composite%纳米CaCO3/PVC复合材料结构形态与冲击性能

    Institute of Scientific and Technical Information of China (English)

    曾晓飞; 陈建峰; 王国全

    2002-01-01

    对改性纳米CaCO3/PVC复合材料进行冲击强度的测试.结果表明,改性纳米CaCO3可提高PVC复合材料的裂缝引发能和裂缝增长能,其中裂缝增长能的提高尤为明显.复合材料的单缺口冲击强度达到81.1kJ( m(2.用透射电子显微镜及扫描电子显微镜观察了纳米CaCO3/PVC复合材料的微观结构及断面形态,发现表面改性后纳米CaCO3在PVC基体中达到了纳米级的分散,复合材料的断面产生了大量的网丝状结构.复合材料的微观结构进一步证实了纳米CaCO3对PVC基体的显著增韧作用.

  14. In situ Raman study of dissolved CaCO3 minerals under subduction zone conditions

    Science.gov (United States)

    Facq, S.; Daniel, I.; Sverjensky, D. A.

    2012-12-01

    The fate and the characteristics of the Earth's deep carbon reservoirs are still not well understood [1]. The connection between the surficial and the deep-Earth carbon cycles occurs at subduction zones where carbon is transported into the mantle and where hydrous silicates and carbonate minerals break down releasing H2O and C-species in fluids associated with mantle metasomatism and the generation of arc volcanism [2]. In order to obtain mass balance between recycling and burial in the deep mantle, the study of the dissolution of CaCO3 minerals in equilibrium with aqueous fluids under mantle conditions is crucial. We report a novel integrated experimental and theoretical study of the equilibration of CaCO3 minerals with aqueous solutions (pure water or NaCl solutions) at high pressures and temperatures (0.5 to 8 GPa and 250 to 500 °C). The fluid speciation was studied using in situ Raman spectroscopy coupled to an externally heated membrane type DAC equipped with 500 μm pure synthetic diamond anvils. In a typical experiment, the aqueous fluid and a calcite crystal [3] were loaded in a rhenium gasket. The pressure was determined from the calibrated shift of the carbonate υ1 symmetric stretching mode of aragonite and the temperature measured with a K-type thermocouple. Raman spectra were recorded using a Labram HR800 Raman spectrometer (Horiba Jobin-Yvon) coupled to a Spectra Physics Ar+ laser. At equilibrium with an aragonite crystal, the Raman data show that bicarbonate is the most abundant species in low-pressure fluids (below 4 GPa) whereas carbonate becomes progressively dominant at higher pressure. After correction from their Raman cross-sections [4], the relative amounts of dissolved carbonate and bicarbonate were estimated from the areas of the Raman bands of the carbonate and bicarbonate ions (υ1 and υ5 symmetric stretching modes, respectively). The presence of sodium chloride influences the speciation by extending the pressure field where the

  15. Analysis on Modification Effect of Ultra-Fine CaCO3 in Sulphoaluminate Cement%超细CaCO3对硫铝酸盐水泥的改性效应分析

    Institute of Scientific and Technical Information of China (English)

    周世华; 卢忠远; 黄佳木; 袁晓露

    2005-01-01

    探讨了超细CaCO3对硫铝酸盐水泥进行改性的研究.试验结果表明:超细CaCO3不仅改善了净浆浆体的流动性,而且明显地提高了水泥的物理力学性能,其硬化浆体的微观结构也更为致密、均匀;并且从颗粒级配,微观和亚微观念结构以及晶核形成角度分析了超细CaCO3在硫铝酸盐水泥中所产生的效应.

  16. PP/POE/PE/CaCO3/PP-g-MAH复合材料力学性能的研究%Study on the Mechanical Properties of PP/POE/PE/CaCO3/PP-g-MAH Composite

    Institute of Scientific and Technical Information of China (English)

    赵伟; 王丽

    2009-01-01

    采用熔融共混法制备聚丙烯,聚烯烃弹性体/聚乙烯/马来酸酐接枝聚丙烯(PP/POE/PE/CaCO3/PP-g-MAH)复合材料,并研究其力学性能.结果表明:PP-g-MAH可提高PP与CaCO3的相容性,使复合材料的韧性和拉伸性能得到提高,PE可提高PP与POE的相容性,并有效提高复合材料的韧性,经POE、PE、CaCO3和PP-g-MAH之间的相互协同改性作用可制得综合性能优良的PP复合材料.

  17. PVC/纳米CaCO3复合材料的制备及其性能研究%Prepration of PVC/Nano-CaCO3 Composite and Study of its Property

    Institute of Scientific and Technical Information of China (English)

    高志生; 马万珍; 薛炳刚

    2007-01-01

    采用硅烷偶联剂KH-570对纳米碳酸钙进行表面处理,然后通过熔融共混法制备聚氯乙烯/纳米碳酸钙(PVC/nano-CaCO3)复合材料,用透射电镜观察了nano-CaCO3粒子在PVC基体中的分散状况.随着nano-CaCO3用量的加大,复合材料的冲击强度和失重残余量都有所提高,热分解温度变化不大,玻璃化转变温度先下降然后又有所增加.

  18. Increased Uptake of HCV Testing through a Community-Based Educational Intervention in Difficult-to-Reach People Who Inject Drugs: Results from the ANRS-AERLI Study.

    Directory of Open Access Journals (Sweden)

    Perrine Roux

    Full Text Available The community-based AERLI intervention provided training and education to people who inject drugs (PWID about HIV and HCV transmission risk reduction, with a focus on drug injecting practices, other injection-related complications, and access to HIV and HCV testing and care. We hypothesized that in such a population where HCV prevalence is very high and where few know their HCV serostatus, AERLI would lead to increased HCV testing.The national multisite intervention study ANRS-AERLI consisted in assessing the impact of an injection-centered face-to-face educational session offered in volunteer harm reduction (HR centers ("with intervention" compared with standard HR centers ("without intervention". The study included 271 PWID interviewed on three occasions: enrolment, 6 and 12 months. Participants in the intervention group received at least one face-to-face educational session during the first 6 months.The primary outcome of this analysis was reporting to have been tested for HCV during the previous 6 months. Statistical analyses used a two-step Heckman approach to account for bias arising from the non-randomized clustering design. This approach identified factors associated with HCV testing during the previous 6 months.Of the 271 participants, 127 and 144 were enrolled in the control and intervention groups, respectively. Of the latter, 113 received at least one educational session. For the present analysis, we selected 114 and 88 participants eligible for HCV testing in the control and intervention groups, respectively. In the intervention group, 44% of participants reported having being tested for HCV during the previous 6 months at enrolment and 85% at 6 months or 12 months. In the control group, these percentages were 51% at enrolment and 78% at 12 months. Multivariable analyses showed that participants who received at least one educational session during follow-up were more likely to report HCV testing, compared with those who did not

  19. HIV protease inhibitors do not cause the accumulation of prelamin A in PBMCs from patients receiving first line therapy: the ANRS EP45 "aging" study.

    Directory of Open Access Journals (Sweden)

    Sophie Perrin

    Full Text Available BACKGROUND: The ANRS EP45 "Aging" study investigates the cellular mechanisms involved in the accelerated aging of HIV-1 infected and treated patients. The present report focuses on lamin A processing, a pathway known to be altered in systemic genetic progeroid syndromes. METHODS: 35 HIV-1 infected patients being treated with first line antiretroviral therapy (ART, mean duration at inclusion: 2.7±1.3 years containing boosted protease inhibitors (PI/r (comprising lopinavir/ritonavir in 65% of patients were recruited together with 49 seronegative age- and sex-matched control subjects (http://clinicaltrials.gov/, NCT01038999. In more than 88% of patients, the viral load was 500/mm³. Prelamin A processing in peripheral blood mononuclear cells (PBMCs from patients and controls was analysed by western blotting at inclusion. PBMCs from patients were also investigated at 12 and 24 months after enrolment in the study. PBMCs from healthy controls were also incubated with boosted lopinavir in culture medium containing various concentrations of proteins (4 to 80 g/L. RESULTS: Lamin A precursor was not observed in cohort patient PBMC regardless of the PI/r used, the dose and the plasma concentration. Prelamin A was detected in PBMC incubated in culture medium containing a low protein concentration (4 g/L but not in plasma (60-80 g/L or in medium supplemented with BSA (40 g/L, both of which contain a high protein concentration. CONCLUSIONS: Prelamin A processing abnormalities were not observed in PBMCs from patients under the PI/r first line regimen. Therefore, PI/r do not appear to contribute to lamin A-related aging in PBMCs. In cultured PBMCs from healthy donors, prelamin A processing abnormalities were only observed when the protein concentration in the culture medium was low, thus increasing the amount of PI available to enter cells. ClinicalTrials.gov NCT01038999 http://clinicaltrials.gov/ct2/show/NCT01038999.

  20. Access to HIV care in the context of universal test and treat: challenges within the ANRS 12249 TasP cluster-randomized trial in rural South Africa

    Directory of Open Access Journals (Sweden)

    Mélanie Plazy

    2016-06-01

    Full Text Available Introduction: We aimed to quantify and identify associated factors of linkage to HIV care following home-based HIV counselling and testing (HBHCT in the ongoing ANRS 12249 treatment-as-prevention (TasP cluster-randomized trial in rural KwaZulu-Natal, South Africa. Methods: Individuals ≥16 years were offered HBHCT; those who were identified HIV positive were referred to cluster-based TasP clinics and offered antiretroviral treatment (ART immediately (five clusters or according to national guidelines (five clusters. HIV care was also available in the local Department of Health (DoH clinics. Linkage to HIV care was defined as TasP or DoH clinic attendance within three months of referral among adults not in HIV care at referral. Associated factors were identified using multivariable logistic regression adjusted for trial arm. Results: Overall, 1323 HIV-positive adults (72.9% women not in HIV care at referral were included, of whom 36.9% (n=488 linked to care 42%, p<0.001. Linkage to care was lower in students (adjusted odds-ratio [aOR]=0.47; 95% confidence interval [CI] 0.24–0.92 than in employed adults, in adults who completed secondary school (aOR=0.68; CI 0.49–0.96 or at least some secondary school (aOR=0.59; CI 0.41–0.84 versus ≤ primary school, in those who lived at 1 to 2 km (aOR=0.58; CI 0.44–0.78 or 2–5 km from the nearest TasP clinic (aOR=0.57; CI 0.41–0.77 versus <1 km, and in those who were referred to clinic after ≥2 contacts (aOR=0.75; CI 0.58–0.97 versus those referred at the first contact. Linkage to care was higher in adults who reported knowing an HIV-positive family member (aOR=1.45; CI 1.12–1.86 versus not, and in those who said that they would take ART as soon as possible if they were diagnosed HIV positive (aOR=2.16; CI 1.13–4.10 versus not. Conclusions: Fewer than 40% of HIV-positive adults not in care at referral were linked to HIV care within three months of HBHCT in the TasP trial. Achieving universal

  1. Associations between 25-hydroxyvitamin D and immunologic, metabolic, inflammatory markers in treatment-naive HIV-infected persons: the ANRS CO9 «COPANA» cohort study.

    Directory of Open Access Journals (Sweden)

    Camille Legeai

    Full Text Available OBJECTIVES: Low 25(OHD has been associated with dyslipidemia, insulin resistance and inflammation in both general and HIV-infected (mostly treated populations. We investigated these associations in antiretroviral-naïve HIV-infected persons. DESIGN: We measured plasma 25(OHD, metabolic, immunologic and inflammatory markers in 355 persons (204 Whites, 151 Blacks at enrollment in the ANRS COPANA cohort. METHODS: 25(OHD levels were categorized <10 ng/mL (severe deficiency and <20 ng/mL (deficiency. Statistical analyses were adjusted for sampling season, ethnicity and the interaction between season and ethnicity. RESULTS: 25(OHD insufficiency (<30 ng/mL, deficiency (<20 ng/mL and severe deficiency (<10 ng/mL were highly prevalent (93%, 67% and 24% of patients, respectively. Blacks had significantly lower 25(OHD than Whites (median: 13 vs. 17 ng/mL, P<0.001, with markedly less pronounced seasonal variation. Smoking and drinking alcohol were associated with having a 25 OHD level<10 ng/mL. In patients with 25(OHD<10 ng/mL, the proportion of persons with a CD4 count<100/mm(3 was higher than in patients with 25(OHD≥10 ng/mL (18.8% vs. 10.7%, P = 0.04. Persons with 25 OHD<10 ng/mL had higher levels of hsCRP (1.60 mg/L [IQR: 0.59-5.76] vs. 1.27 mg/L [0.58-3,39], P = 0.03 and resistin (16.81 ng/L [IQR: 13.82-25.74] vs. 11.56 ng/L [IQR: 8.87-20.46], P = 0.02, and, among Blacks only, sTNFR2 (2.92 ng/mL [2.31-4.13] vs. 2.67 ng/mL, [1.90-3.23], P = 0.04. The strength and significance of the association between CD4<100/mm(3 and 25 OHD<10 ng/mL were reduced after adjustment on sTNFR1, sTNFR2, and hsCRP levels. In multivariate analysis, a CD4 count <100/mm(3, resistin concentration and smoking were independently associated with 25(OHD<10 ng/mL. CONCLUSIONS: Severe vitamin D deficiency was associated with low CD4 counts and increased markers of inflammation in ARV-naïve HIV-infected persons.

  2. Increased Uptake of HCV Testing through a Community-Based Educational Intervention in Difficult-to-Reach People Who Inject Drugs: Results from the ANRS-AERLI Study

    Science.gov (United States)

    Roux, Perrine; Rojas Castro, Daniela; Ndiaye, Khadim; Debrus, Marie; Protopopescu, Camélia; Le Gall, Jean-Marie; Haas, Aurélie; Mora, Marion; Spire, Bruno; Suzan-Monti, Marie; Carrieri, Patrizia

    2016-01-01

    Aims The community-based AERLI intervention provided training and education to people who inject drugs (PWID) about HIV and HCV transmission risk reduction, with a focus on drug injecting practices, other injection-related complications, and access to HIV and HCV testing and care. We hypothesized that in such a population where HCV prevalence is very high and where few know their HCV serostatus, AERLI would lead to increased HCV testing. Methods The national multisite intervention study ANRS-AERLI consisted in assessing the impact of an injection-centered face-to-face educational session offered in volunteer harm reduction (HR) centers (“with intervention”) compared with standard HR centers (“without intervention”). The study included 271 PWID interviewed on three occasions: enrolment, 6 and 12 months. Participants in the intervention group received at least one face-to-face educational session during the first 6 months. Measurements The primary outcome of this analysis was reporting to have been tested for HCV during the previous 6 months. Statistical analyses used a two-step Heckman approach to account for bias arising from the non-randomized clustering design. This approach identified factors associated with HCV testing during the previous 6 months. Findings Of the 271 participants, 127 and 144 were enrolled in the control and intervention groups, respectively. Of the latter, 113 received at least one educational session. For the present analysis, we selected 114 and 88 participants eligible for HCV testing in the control and intervention groups, respectively. In the intervention group, 44% of participants reported having being tested for HCV during the previous 6 months at enrolment and 85% at 6 months or 12 months. In the control group, these percentages were 51% at enrolment and 78% at 12 months. Multivariable analyses showed that participants who received at least one educational session during follow-up were more likely to report HCV testing

  3. Preparation of Co3O4 Nanostructures via a Hydrothermal- Assisted Thermal Treatment Method by Using of New Precursors

    Science.gov (United States)

    Gholamrezaei, Sousan; Salavati-Niasari, Masoud; Hadadzadeh, Hassan; Behnamfar, Mohammad Taghi

    2017-02-01

    Co3O4 nanostructures have been synthesized via a hydrothermal-assisted thermal treatment process. A new complex formulated as [Co(py)2(H2O)2(NO3)2] was synthesized, and then used to prepare Co3O4 nanostructures. Cubic phase of spinel Co3O4 nanostructures with particle size of about 39 nm could be produced after calcination of the Co(OH)2 materials prepared with hydrothermal method at 160 °C for 15 h. Using of inorganic precursors decreased the time and temperature of Co3O4 preparation. The effect of pH on the morphology of the product s synthesized by hydrothermal reactions was investigated. It was found that the best morphology was achieved on pH=8, where was not prepared any precipitation. In this method, we could decrease the reaction temperature in synthetic rout to fabricate Co3O4 nanostructures. Nanostructures were characterized by SEM, TEM, X-ray diffraction (XRD), UV-visible, Fourier transformed infrared (FT-IR) spectroscopy and Nuclear magnetic resonance (1H-NMR).

  4. Potential of porous Co3O4 nanorods as cathode catalyst for oxygen reduction reaction in microbial fuel cells.

    Science.gov (United States)

    Kumar, Ravinder; Singh, Lakhveer; Zularisam, A W; Hai, Faisal I

    2016-11-01

    This study aims to investigate the potential of porous Co3O4 nanorods as the cathode catalyst for oxygen reduction reaction (ORR) in aqueous air cathode microbial fuel cells (MFCs). The porous Co3O4 nanorods were synthesized by a facile and cost-effective hydrothermal method. Three different concentrations (0.5mg/cm(2), 1mg/cm(2), and 2mg/cm(2)) of Co3O4 nanorods coated on graphite electrodes were used to test its performance in MFCs. The results showed that the addition of porous Co3O4 nanorods enhanced the electrocatalytic activity and ORR kinetics significantly and the overall resistance of the system was greatly reduced. Moreover, the MFC with a higher concentration of the catalyst achieved a maximum power density of 503±16mW/m(2), which was approximately five times higher than the bare graphite electrode. The improved catalytic activity of the cathodes could be due to the porous properties of Co3O4 nanorods that provided the higher number of active sites for oxygen.

  5. [High-level production of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) by feb-batch culture of Alcaligenes eutrophus].

    Science.gov (United States)

    Cai, Y B; Liu, M Q; Yi, Z H; Chen, Q; Weng, W Q

    2001-09-01

    Fermentation strategies for production P (3HB-co-3HV) from glucose and propionic (or valeric) acid by Alcaligenes eutrophus were studied. During the culture, we controlled pH of the broth by feeding precusors of 3HV- propionic or valeric acid after Ammonia feeding stopped. When propionic acid were used as the precusor, for 50 hours, we obtained a cell dry weight, a P(3HB-co-3HV) concentration, a P(3HB-co-3HV) content and a 3HV fraction of 149.9 g/L, 124.9 g/L, 83.3% and 12.4 mol%, respectively, with a PHA productivity of 2.50 g h-1 L-1. When valeric acid were used as the precusor, for 45 hours, we obtained a cell dry weight, a P(3HB-co-3HV) concentration, a P(3HB-co-3HV) content and a 3HV fraction of 160.2 g/L, 119.0 g/L, 74.2% and 17.7 mol%, respectively, with a PHA productivity of 2.64 g h-1 L-1. Prior to this study, it hasn't been reported to obtain such high level productivity and 3HV fraction at the same time by Alcaligenes eutrophus.

  6. Net loss of CaCO3 from coral reef communities due to human induced seawater acidification

    Science.gov (United States)

    Andersson, A.J.; Kuffner, I.B.; MacKenzie, F.T.; Jokiel, P.L.; Rodgers, K.S.; Tan, A.

    2009-01-01

    Acidification of seawater owing to oceanic uptake of atmospheric CO2 originating from human activities such as burning of fossil fuels and land-use changes has raised serious concerns regarding its adverse effects on corals and calcifying communities. Here we demonstrate a net loss of calcium carbonate (CaCO3) material as a result of decreased calcification and increased carbonate dissolution from replicated subtropical coral reef communities (n=3) incubated in continuous-flow mesocosms subject to future seawater conditions. The calcifying community was dominated by the coral Montipora capitata. Daily average community calcification or Net Ecosystem Calcification (NEC=CaCO3 production – dissolution) was positive at 3.3 mmol CaCO3 m−2 h−1 under ambient seawater pCO2 conditions as opposed to negative at −0.04 mmol CaCO3 m−2h−1 under seawater conditions of double the ambient pCO2. These experimental results provide support for the conclusion that some net calcifying communities could become subject to net dissolution in response to anthropogenic ocean acidification within this century. Nevertheless, individual corals remained healthy, actively calcified (albeit slower than at present rates), and deposited significant amounts of CaCO3 under the prevailing experimental seawater conditions of elevated pCO2.

  7. Investigating the Relation between CO (3-2) and Far Infrared Luminosities for Nearby Merging Galaxies Using ASTE

    CERN Document Server

    Michiyama, Tomonari; Nakanishi, Kouichiro; Ueda, Junko; Saito, Toshiki; Ando, Misaki; Kaneko, Hiroyuki; Yamashita, Takuji; Matsuda, Yuichi; Hatsukade, Bunyo; Kikuchi, Kenichi; Komugi, Shinya; Muto, Takayuki

    2016-01-01

    We present the new single dish CO (3-2) emission data obtained toward 19 early stage and 7 late stage nearby merging galaxies using the Atacama Submillimeter Telescope Experiment (ASTE). Combining with the single dish and interferometric data of galaxies observed in previous studies, we investigate the relation between the CO (3-2) luminosity (L'CO(3-2)) and the far Infrared luminosity (LFIR) in a sample of 29 early stage and 31 late stage merging galaxies, and 28 nearby isolated spiral galaxies. We find that normal isolated spiral galaxies and merging galaxies have different slopes (alpha) in the log L'CO(3-2) - log LFIR plane (alpha ~ 0.79 for spirals and ~ 1.12 for mergers). The large slope (alpha > 1) for merging galaxies can be interpreted as an evidence for increasing Star Formation Efficiency (SFE=LFIR/L'CO(3-2)) as a function of LFIR. Comparing our results with sub-kpc scale local star formation and global star-burst activity in the high-z Universe, we find deviations from the linear relationship in t...

  8. Incommensurately modulated twin structure of nyerereite Na1.64K0.36Ca(CO3)2.

    Science.gov (United States)

    Bolotina, Nadezhda B; Gavryushkin, Pavel N; Korsakov, Andrey V; Rashchenko, Sergey V; Seryotkin, Yurii V; Golovin, Alexander V; Moine, Bertrand N; Zaitsev, Anatoly N; Litasov, Konstantin D

    2017-04-01

    The incommensurately modulated twin structure of nyerereite Na1.64K0.36Ca(CO3)2 has been first determined in the (3 + 1)-dimensional symmetry group Cmcm(α00)00s with modulation vector q = 0.383a*. Unit-cell values are a = 5.062 (1), b = 8.790 (1), c = 12.744 (1) Å. Three orthorhombic components are related by threefold rotation about [001]. Discontinuous crenel functions are used to describe the occupation modulation of Ca and some CO3 groups. The strong displacive modulation of the O atoms in vertexes of such CO3 groups is described using x-harmonics in crenel intervals. The Na, K atoms occupy mixed sites whose occupation modulation is described in two ways using either complementary harmonic functions or crenels. The nyerereite structure has been compared both with the commensurately modulated structure of K-free Na2Ca(CO3)2 and with the widely known incommensurately modulated structure of γ-Na2CO3.

  9. Decomposition of silver carbonate; the crystal structure of two high-temperature modifications of Ag(2)CO(3).

    Science.gov (United States)

    Norby, P; Dinnebier, R; Fitch, A N

    2002-07-15

    High-resolution powder diffraction was used to study the thermal transformation of silver carbonate. A sample of Ag(2)CO(3) was heated in a capillary under 4.5 atm CO(2) pressure. The decomposition temperature of silver carbonate to silver oxide is thereby increased, allowing high-resolution synchrotron X-ray powder diffraction patterns of the two high-temperature phases of Ag(2)CO(3) to be collected. The structure of the low-temperature (lt) phase was confirmed, and the structures of the two high-temperature phases were determined by direct methods and refined using the Rietveld method: lt-Ag(2)CO(3) (295 K) P2(1)/m, z = 2, a = 4.8521(2) A, b = 9.5489(4) A, c = 3.2536(1) A, beta = 91.9713(3) degrees; beta-Ag(2)CO(3) (453 K) P31c, z = 6, a = 9.1716(4) A, c = 6.5176(3) A; alpha-Ag(2)CO(3) (476 K) P6 macro 2m, z = 3, a = 9.0924(4) A, c = 3.3249(1) A. In addition, thermal expansion properties, anisotropic microstrain distributions, and thermal transformations of the three silver carbonate phases and silver oxide are described.

  10. Studies on ethylbenzene dehydrogenation with CO2 as soft oxidant over Co3O4/COK-12 catalysts

    Indian Academy of Sciences (India)

    Ramudu Pochamoni; Anand Narani; Mohan Varkolu; Murali Dhar Gudimella; S Sai Prasad Potharaju; David Raju Burri; Seetha Rama Rao Kamaraju

    2015-04-01

    Oxidative dehydrogenation of ethylbenzene to styrene has been studied over Co3O4 supported on mesoporous silica (COK-12) with CO2 as soft oxidant in a fixed bed reactor at atmospheric pressure in the temperature range of 723 to 923K. While COK-12 has been prepared by self-assembly method using long chain ionic surfactant i.e., P123 as template, cobalt oxide supported on COK-12 catalysts with variable Co content have been synthesised by simple wet impregnation technique. All the catalysts were characterized by N2 adsorption - desorption, XRD, FT-IR, TPR, UV-Vis and XPS techniques. XRD and pore size distribution studies indicate the intactness of mesoporous structure of SiO2 even after incorporation of Co3O4. Presence of Co3O4 crystallites were observed beyond 5 wt% Co loading. High ethylbenzene conversion and stable styrene yields have been observed over 3% Co3O4/COK-12 catalyst due to the presence of large number of active Co3O4 catalytic sites. Enhancement in the activity has been observed with CO2 as soft oxidant than with N2 as diluent. This is because of the fact that the liberated H2 reacts with CO2 in the form of reverse water gas shift reaction.

  11. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) co-polymer production from a local isolate, Brevibacillus invocatus MTCC 9039.

    Science.gov (United States)

    Sankhla, Indu Singh; Bhati, Ranjana; Singh, Akhilesh Kumar; Mallick, Nirupama

    2010-03-01

    Accumulation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] co-polymer by a local isolate, Brevibacillus invocatus MTCC 9039 under batch mode was investigated under glucose, acetate and propionate-supplemented conditions. Cells harvested at the stationary phase of growth depicted maximum accumulation of poly-3-hydroxybutyrate (PHB), i.e. 3% of dry cell weight (dcw) at pH 7.0 and temperature 30 degrees C at 48h of incubation. PHB accumulation reached up to 52% (dcw) under 3% glucose with 1% acetate supplementation. P(3HB-co-3HV) co-polymer synthesis was observed under propionate-supplemented condition, which reached up to 45% under 3% glucose with 1% propionate supplementation. Optimization of process parameters by response surface methodology (RSM) resulted into co-polymer accumulation up to 65% (dcw) at 2.08% glucose, 1.62% acetate, 0.75% propionate and 2.15 g l(-1) KH(2)PO(4) concentrations. This co-polymer exhibited comparable material properties with the commercial [P(3HB-co-3HV)] co-polymers, whereas the elasticity was tremendously high and could be comparable with polypropylene. Thus, B. invocatus MTCC 9039 is emerging as an interesting organism and could be exploited further for P(3HB-co-3HV) co-polymer production.

  12. Adsorption study of anionic reactive dye from aqueous solution to Mg-Fe-CO3 layered double hydroxide (LDH)

    Science.gov (United States)

    Ahmed, I. M.; Gasser, M. S.

    2012-10-01

    Mg-Fe-Cl Layered double hydroxides (LDHs) have been prepared using a method involving separate nucleation and aging steps with Mg/Fe = 3. The interlayer anions readily replaced by carbonate are characterized by X-ray diffraction (XRD) and FTIR. The effects of different parameters, such as pH, contact time, concentration of dye and temperature on the capacity and adsorption mechanism of Mg-Fe-CO3-LDH in removing an anionic dye (congo red, CR) from aqueous solution were separately investigated. The results show that Mg-Fe-CO3-LDH is particularly efficient in removing CR and the dye removal increases with decreasing pH. The adsorption of CR on Mg-Fe-CO3-LDH reached equilibrium after 15 min where 100 mg/L CR was removed. The equilibrium isotherm indicates that the adsorption of CR onto Mg-Fe-CO3-LDH fits to Langmuir and Freundlich equation as well. The adsorption data obtained from the Langmuir model gave good values of the determination coefficient and the saturated adsorption capacity of Mg-Fe-CO3-LDH for CR was found to be 104.6 mg/g. The regeneration study indicates that the prepared LDH could be used for several cycles. The thermodynamic parameters have been calculated, and the adsorption process was found to be spontaneous, endothermic in nature and follows a pseudo-second-order kinetic model.

  13. Seal glass compatibility with bare and (Mn,Co) 3O 4 coated Crofer 22 APU alloy in different atmospheres

    Science.gov (United States)

    Mahapatra, M. K.; Lu, K.

    To prevent gas mixing and leakage during solid oxide fuel/electrolyzer cell operation, the interconnect/seal glass interface should bond well and remain stable. A SrO-La 2O 3-Al 2O 3-SiO 2 (SABS-0) seal glass has been bonded to bare Crofer 22 APU alloy and (Mn,Co) 3O 4 coated Crofer 22 APU alloy. The stability of the interconnect/SABS-0 interface has been studied in air and H 2/H 2O atmospheres at 800 °C for 1000 h. The interconnect/seal glass interaction involves the oxidation of the bare and (Mn,Co) 3O 4 coated Crofer 22 APU alloy surfaces, inter-diffusion of elements, chemical reaction, and the devitrification of the SABS-0 glass. The study shows that the thermal treatment atmosphere greatly affects the interfacial stability of both bare Crofer 22 APU/SABS-0 and (Mn,Co) 3O 4 coated Crofer 22 APU/SABS-0 samples. The interfacial stability is better in the H 2/H 2O atmosphere for both samples. The instability of the (Mn,Co) 3O 4 coating under the thermal treatment conditions degrades the interfacial compatibility of the (Mn,Co) 3O 4 coated Crofer 22 APU/SABS-0 sample.

  14. Liquid-Liquid Equilibrium for 1-Butanol-Water-KF and 1-Butanol-Water-K2CO3 Systems

    Institute of Scientific and Technical Information of China (English)

    XU Wen-you; JI Min

    2005-01-01

    KF or K2CO3 was added into the 1-butanol-water system and two phases were formed: water-rich phase (water phase) and 1-butanol-rich phase (1-butanol phase). The liquid-liquid equilibrium (LLE) data for 1-butanol-water-KF and 1-butanol-water-K2 CO3 systems were measured at 25 C and showed that 1-butanol phase contained negligible salt and water phase contained negligible 1-butanol when the concentrations of KF and K2CO3 in the water phase were equal to or higher than 27. 11% and 31. 68%, respectively. Thus water could be separated efficiently from 1-butanol-water by adding KF or K2CO3 into the system. A theoretical calculation of LLE data was calculated by using the Pitzer theory to get water activity in the water phase, and by the models, such as the Wilson, NRTL or the UNIQUAC for the 1-butanol phase.For 1-butanol-water-KF system, the experimental data were found in good agreement with the calculated results by using Pitzer theory and Wilson equation, while for 1-butanol-water-K2CO3 system, the experimental data were found in good agreement with the calculated results by using Pitzer theory and UNIQUAC equation.

  15. Cauliflower-Like Co3O4/Three-Dimensional Graphene Composite for High Performance Supercapacitor Applications

    Directory of Open Access Journals (Sweden)

    Huili Liu

    2015-01-01

    Full Text Available Cauliflower-like Co3O4/three-dimensional (3D graphene nanocomposite material was synthesized by a facile two-step synthesis route (heat reduction of graphite oxide (GO and hydrothermal synthesis of Co3O4. The phase composition, morphology, and structure of the as-obtained products were characterized by scanning electron microscopy (SEM, transmission electron microscope (TEM, and X-ray diffraction (XRD. Electrochemical properties as supercapacitor electrode materials were systematically investigated by cyclic voltammetry (CV and constant current charge-discharge tests. It was found that the Co3O4/3D graphene composite showed a maximum specific capacitance of 863 F g−1, which was obtained by means of CVs at a scan rate of 1 mV s−1 in 6 M KOH aqueous solution. Moreover, the composite exhibited improved cycling stability after 1,000 cycles. The good supercapacitor performance is ascribed to the combination of 3D graphene and cauliflower-like Co3O4, which leads to a strong synergistic effect to remarkably boost the utilization ratio of Co3O4 and graphene for high capacitance.

  16. Intumescent flame retardants/CaCO3 synergistic flame retardant epoxy resin%膨胀阻燃剂/CaCO3协效阻燃环氧树脂

    Institute of Scientific and Technical Information of China (English)

    杨守生; 王学宝; 陈英辉

    2013-01-01

    The effects on the flame retardant and mechanical properties of epoxy resin by compounded flame retardant system consisting of DOPOMPC/APP and composite flame retardant system of nano-sized CaCO3 were studied. It was found that nano-sized CaCO3 and intumescent flame retardant system showed synergistic effect. Comparing with flame retarded epox-y resin without nano-sized CaCO3 , with 3 % of nano-sized Ca-CO3 , the LOI of flame retarded epoxy resin reached to 39. 4 and the pk-HRR decreased by 33. 6%. It was also observed that the flame retarded epoxy resin showed 187% improvement in tensile strength, 53. 3% improvement in flexural strength and 255% improvement in impact strength. The comprehensive performance of fire retardant resin is good.%研究了六(4一DOPO羟甲基苯氧基)环三磷腈/多聚磷酸铵(DOPOMPC/APP)膨胀阻燃体系与纳米碳酸钙构成的复合阻燃体系对环氧树脂阻燃性能和力学性能的影响.结果表明,纳米碳酸钙与膨胀阻燃体系有一定的阻燃协同作用,当添加3% CaCO3时,阻燃EP的LOI达到39.4,与未加纳米CaCO3比较,pk— HRR降低了33.6%,拉伸强度、弯曲强度、冲击强度分别提高了1.87倍、53.3%、2.55倍,呈现出良好的综合性能.

  17. Effect of Calcination Temperature on Surface Oxygen Vacancies and Catalytic Performance Towards CO Oxidation of Co3O4 Nanoparticles Supported on SiO2

    Institute of Scientific and Technical Information of China (English)

    Jin-bing Li; Zhi-quan Jiang; Kun Qian; Wei-xin Huang

    2012-01-01

    Co3O4/SiO2 catalysts for CO oxidation were prepared by conventional incipient wetness impregnation followed by calcination at various temperatures.Their structures were characterized with X-ray diffraction (XRD),laser Raman spectroscopy,X-ray photoelectron spectroscopy (XPS),temperature-programmed reduction (TPR) and X-ray absorption fine structure (XAFS) spectroscopy.Both XRD and Raman spectroscopy only detect the existence of Co3O4 crystallites in all catalysts.However,XPS results indicate that excess Co2+ ions are present on the surface of Co3O4 in Co3O4(200)/SiO2 as compared with bulk Co3O4.Meanwhile,TPR results suggest the presence of surface oxygen vacancies on Co3O4 in Co3O4(200)/SiO2,and XAFS results demonstrate that Co3O4 in Co3O4(200)/SiO2 contains excess Co2+.Increasing calcination temperature results in oxidation of excess Co2+and the decrease of the concentration of surface oxygen vacancies,consequently the formation of stoichiometric Co3O4 on supported catalysts.Among all Co3O4/SiO2 catalysts,Co3O4(200)/SiO2 exhibits the best catalytic performance towards CO oxidation,demonstrating that excess Co2+ and surface oxygen vacancies can enhance the catalytic activity of Co3O4 towards CO oxidation.These results nicely demonstrate the effect of calcination temperature on the structure and catalytic performance towards CO oxidation of silicasupported Co3O4 catalysts and highlight the important role of surface oxygen vacancies on Co3O4.

  18. Effect of Calcination Temperature on Surface Oxygen Vacancies and Catalytic Performance Towards CO Oxidation of Co3O4 Nanoparticles Supported on SiO2

    Science.gov (United States)

    Li, Jin-bing; Jiang, Zhi-quan; Qian, Kun; Huang, Wei-xin

    2012-02-01

    Co3O4/SiO2 catalysts for CO oxidation were prepared by conventional incipient wetness impregnation followed by calcination at various temperatures. Their structures were characterized with X-ray diffraction (XRD), laser Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR) and X-ray absorption fine structure (XAFS) spectroscopy. Both XRD and Raman spectroscopy only detect the existence of Co3O4 crystallites in all catalysts. However, XPS results indicate that excess Co2+ ions are present on the surface of Co3O4 in Co3O4(200)/SiO2 as compared with bulk Co3O4. Meanwhile, TPR results suggest the presence of surface oxygen vacancies on Co3O4 in Co3O4(200)/SiO2, and XAFS results demonstrate that Co3O4 in Co3O4(200)/SiO2 contains excess Co2+. Increasing calcination temperature results in oxidation of excess Co2+ and the decrease of the concentration of surface oxygen vacancies, consequently the formation of stoichiometric Co3O4 on supported catalysts. Among all Co3O4/SiO2 catalysts, Co3O4(200)/SiO2 exhibits the best catalytic performance towards CO oxidation, demonstrating that excess Co2+ and surface oxygen vacancies can enhance the catalytic activity of Co3O4 towards CO oxidation. These results nicely demonstrate the effect of calcination temperature on the structure and catalytic performance towards CO oxidation of silica-supported Co3O4 catalysts and highlight the important role of surface oxygen vacancies on Co3O4.

  19. LTR real-time PCR for HIV-1 DNA quantitation in blood cells for early diagnosis in infants born to seropositive mothers treated in HAART area (ANRS CO 01).

    Science.gov (United States)

    Avettand-Fènoël, Véronique; Chaix, Marie-Laure; Blanche, Stéphane; Burgard, Marianne; Floch, Corinne; Toure, Kadidia; Allemon, Marie-Christine; Warszawski, Josiane; Rouzioux, Christine

    2009-02-01

    HIV-1 diagnosis in babies born to seropositive mothers is one of the challenges of HIV epidemics in children. A simple, rapid protocol was developed for quantifying HIV-1 DNA in whole blood samples and was used in the ANRS French pediatric cohort in conditions of prevention of mother-to-child transmission. A quantitative HIV-1 DNA protocol (LTR real-time PCR) requiring small blood volumes was developed. First, analytical reproducibility was evaluated on 172 samples. Results obtained on blood cell pellets and Ficoll-Hypaque separated mononuclear cells were compared in 48 adult HIV-1 samples. Second, the protocol was applied to HIV-1 diagnosis in infants in parallel with plasma HIV-RNA quantitation. This prospective study was performed in children born between May 2005 and April 2007 included in the ANRS cohort. The assay showed good reproducibility. The 95% detection cut-off value was 6 copies/PCR, that is, 40 copies/10(6) leukocytes. HIV-DNA levels in whole blood were highly correlated with those obtained after Ficoll-Hypaque separation (r = 0.900, P mothers have received HAART.

  20. 反渗透系统中Zn2+对CaCO3结垢的阻滞%Inhibition of CaCO3 Scaling in Reverse Osmosis System by Zinc Ion

    Institute of Scientific and Technical Information of China (English)

    杨庆峰

    2006-01-01

    Scaling of reverse osmosis (RO) membrane surface is one of the main problems in desalination processes. To mitigate scales, organic anti-sealants are often used. If the dosages of anti-scalants are reduced, by using other much cheaper scale inhibitors, RO running cost will decrease greatly. The present paper investigated the inhibition of CaCO3 precipitation by zinc ions in RO system. The results show that the zinc ion concentration of 2mg. L-1 was able to exert a marked suppression effect on both bulk precipitation of CaCO3 and on membrane scaling on waters of moderate hardness.

  1. Co3O4/GO和Mn3O4/GO催化Oxone氧化NOx的比较研究%The comparative study on Co3O4/GO and Mn3O4/GO catalytic Oxoneoxidation NOx

    Institute of Scientific and Technical Information of China (English)

    万凤至; 朱少波

    2014-01-01

    文章比较了Co3O4/GO及Mn3O4/GO两种催化剂催化Oxone对NOx氧化效果的影响,考察了pH、Oxone投加量及温度等因素对催化Oxone氧化NOx效果的影响.研究结果表明:在相同的试验情况下,Co3O4/GO催化Oxone氧化NOx的效果要优于Mn3O4/GO.

  2. Study on Unsaturated Polyester Resins Strengthened and Toughened by CaCO3 Whisker%CaCO3晶须补强增韧不饱和聚酯树脂的研究

    Institute of Scientific and Technical Information of China (English)

    门晓刚; 刘飞; 曹建新

    2011-01-01

    The unsaturated polyester resins(UPR) was modified by using CaCO3 whiskers as strengthening agent for its low strength, brittleness and other defects, and the effects of content of CaCO3 whisker on the mechanical properties of resin composites were studied. The results showed that when the filling amount of CaC03 whisker is 5%, the tensile strength and maximum flexural strength of the UPR/CaCO3 whisker material are 39.2MPa and 52. 7MPa, which were increased respectively by 126% and 73% compared with the resin matrix; when CaCO3 whisker filler content increased from 2.5% to 5%, there was an obvious brittle - ductile transition and when the addition was 7.5%, the UPR/CaCO3 whisker impact strength of composites compared with the resin matrix was increased by 164%.%针对不饱和聚酯树脂(UPR)强度低、脆性大等缺陷,用添加碳酸钙晶须的方法对其进行改性,研究了碳酸钙晶须用量对树脂复合材料力学性能的影响。结果表明:当CaC03晶须的掺量为5%时,UPR/CaCO3晶须复合材料的拉伸强度、弯曲强度达到极大值39.2MPa、52.7MPa,比树脂基体分别提高了126%和73%;当CaCO3晶须的掺量由2.5%增加到5%时,出现了明显的脆韧转变,加入量为7.5%时,UPR/CaCO3晶须复合材料的冲击强度比树脂基体提高了164%。

  3. Investigation of CaCO3 fouling in plate heat exchangers

    Science.gov (United States)

    Li, Wei; Zhou, Kan; Manglik, Raj M.; Li, Guan-Qiu; Bergles, Arthur E.

    2016-11-01

    An experimental investigation, coupled with theoretical modeling of CaCO3 fouling in plate-and-frame type heat exchangers (PHEs) have been conducted. Four different plates, made of SS-304, are used in two different surface patterns (chevron and zig-zag) of varying corrugation severity (waviness depth and pitch) and area enhancement. They were further characterized in clean, non-fouled convection by their measured heat transfer coefficients and friction factors in the Reynolds number range of 600-6000. The flow-fouling experiments delineate the effects of temperature and plate-surface geometry on growth rates and stabilization of fouling resistance, along with the anti-fouling behavior of plates coated with a hydrophobic PTFE (Teflon) film. Moreover, the microscopic structure of fouling deposits is mapped in a scanning-electron microscope. Corrugated plates with the largest height-to-pitch ratio and hydraulic diameter are found to have the lowest fouling growth rate and resistance; Teflon-film coating of plate surface is also found to mitigate fouling relative to the performance of bare stainless steel plates. Finally, a semi-empirical fouling model, based on the Prandtl-Taylor analogy, has been devised to describe the experimental data and provide a predictive tool.

  4. Bioactive surface modification on amide-photografted poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

    Energy Technology Data Exchange (ETDEWEB)

    Ke Yu; Xue Wei [Institute of Life and Health Engineering, Jinan University, Guangzhou (China); Wang Yingjun; Ren Li; Wu Gang, E-mail: lisa6863@163.com [Biomaterial Research Institute, College of Material Science and Engineering, South China University of Technology, Guangzhou (China)

    2011-04-15

    Collagen was chemically immobilized on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) films via hydrophilic polyacrylamide spacers, aiming to establish the bioactive surface and the inner surface models. The inner surface modified films presented higher wettability than the surface modified films. Wide-angle x-ray diffraction results showed that the d-spacing values of the inner surface model increased compared with those of the surface model, but there was no significant difference between the amide- and collagen-modified PHBV films. The peak melting temperatures of PHBV and the special endotherm around 70 {sup 0}C were following the order: PHBV > amide-modified PHBV > collagen-modified PHBV. The weight loss of the collagen-modified PHBV (inner surface model) might involve hydrolyzation and mineralization during 360 days of incubation, with a maximum value of 18.24%, while PHBV films did not show significant weight loss. The pH value of the degradation fluids fluctuated in the range of 6.86-7.22, as the initial pH was recorded at 7.20. Based on the surface model, collagen-modified PHBV scaffolds were prepared, which enhanced chondrocyte adhesion and spread on the biomimetic surface. Two surface modification models might develop a protocol with a view to generating a biocompatible and biomechanical scaffold for use in meniscus regeneration.

  5. Fabrication of Porous Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate Monoliths via Thermally Induced Phase Separation

    Directory of Open Access Journals (Sweden)

    Takashi Tsujimoto

    2016-02-01

    Full Text Available This study deals with the fabrication of biodegradable porous materials from bacterial polyester, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate (P3HB3HHx, via thermally induced phase separation. P3HB3HHx monoliths with topological porous structure were prepared by dissolution of P3HB3HHx in dimethyl sulfoxide (DMSO at 85 °C and subsequent quenching. The microstructure of the resulting P3HB3HHx monoliths was changed by the P3HB3HHx concentration of the polymer solution. Differential scanning calorimetry and polarized optical microscope analysis revealed that the P3HB3HHx monoliths crystallized during phase separation and the subsequent aging. The mechanical properties, such as compression modulus and stress, of the monoliths depended on the 3-hydroxyhexanoate content of P3HB3HHx. Furthermore, the P3HB3HHx monolith absorbed linseed oil in preference to water in a plant oil–water mixture. In combination with the biodegradable character of P3HB3HHx, the present study is expected to contribute to the development of bio-based materials.

  6. Adsorption of Congo Red by Ni/Al-CO3: Equilibrium, Thermodynamic and Kinetic Studies

    Directory of Open Access Journals (Sweden)

    N. Ayawei

    2015-09-01

    Full Text Available Experimental investigations were carried out using Ni/Al-CO3 layered double hydroxide as adsorbent for removal of toxic anionic dye namely Congo red from aqueous solutions. The effect of contact time, initial dye concentration and temperature were experimentally studied in batch mode to evaluate the kinetic, equilibrium and thermodynamic parameters of the adsorption process. Experimental results revealed that the degradation of the dye is mostly dependent on temperature. The dye degradation process obeyed the zero-order kinetic model, first-order kinetic model, second-order kinetic model, pseudo second order kinetic and third order kinetic model with correlation coefficient values 1, 0.9998, 0.9999, 0.9999 and 0.9997 respectively. Langmuir, Freundlich, Temkin and Dubinin-Kaganer-Radushkevic isotherms were applied to the equilibrium data and was well described by all. Thermodynamic studies showed congo red adsorption on the layered double hydroxide was endothermic and spontaneous in nature. The results indicate that layered double hydroxide could be employed as alternative for removal of anionic dyes from industrial wastewater.

  7. Heat switch effect in an antiferromagnetic insulator Co3V2O8

    Science.gov (United States)

    Zhao, X.; Wu, J. C.; Zhao, Z. Y.; He, Z. Z.; Song, J. D.; Zhao, J. Y.; Liu, X. G.; Sun, X. F.; Li, X. G.

    2016-06-01

    We report a heat switch effect in single crystals of an antiferromagnet Co3V2O8, that is, the thermal conductivity (κ) can be changed with magnetic field in an extremely large scale. Due to successive magnetic phase transitions at 12-6 K, the zero-field κ(T ) displays a deep minimum at 6.7 K and rather small magnitude at low temperatures. Both the temperature and field dependencies of κ demonstrate that the phonons are strongly scattered at the regime of magnetic phase transitions. Magnetic field can suppress magnetic scattering effect and significantly recover the phonon thermal conductivity. In particular, a 14 T field along the a axis increases the κ at 7.5 K up to 100 times. For H ∥c , the magnitude of κ can be suppressed down to ˜8% at some field-induced transition and can be enhanced up to 20 times at 14 T. The present results demonstrate that it is possible to design a kind of heat switch in the family of magnetic materials.

  8. New insight into the stability of CaCO3 surfaces and nanoparticles via molecular simulation.

    Science.gov (United States)

    Bano, A Matthew; Rodger, P Mark; Quigley, David

    2014-07-01

    Using updated and improved atomistic models for the polymorphs of calcium carbonate and their constituent ions in solution, we revisit the question of surface energetics and nanoparticle stability. Using a simple lattice-based Monte Carlo scheme, we generate nanoparticle configurations in vacuum for all three biologically relevant polymorphs of calcium carbonate and establish that the bulk energetic ordering of polymorphs persists to the nanoscale. In aqueous environments, results based on surface enthalpy alone indicate that formation of mineral-water interfaces is marginally favorable in many cases. Including an estimate of lost entropy due to formation of structured water layers is sufficient to reverse this observation, implying a delicate balance of enthalpy and entropy at crystalline CaCO3. In contradiction to some previous studies, we find that small calcite nanoparticles with diameters in the range of 1.8-4.1 nm do not retain an ordered structure on nanosecond time scales. The consequences of these results for simulation studies of biomineralization are discussed.

  9. Study on soil solidification based on microbiological precipitation of CaCO3

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The soil solidifying technology started booming from the 1940s and formed an integrated cross-discipline.This paper aimed to study the effect and mechanism of soil solidification by microorganisms.Soil specimens treated by different methods were designed.Then the compressive strengths of these specimens on day 7 were tested and the situ bacteria culturing technique in soil was investigated.Finally the mechanism of soil solidification by microorganisms was explored according to the decomposition rate of substrate,pH value and the SEM and XRD analysis.Experimental results showed that the soil could be solidified by filling enhancement and precipitation of microorganisms.The compressive strength increased with bacteria A but decreased with substrate B,and soil specimen got a higher strength with bacteria situ cultured.The suitable pH value for bacteria A was 8–9,and the delay of lime addition could make substrate decomposition more completely,lower the influence by the existence of substrate,and improve the strength.In XRD and SEM images,precipitation of CaCO3 could be speculated.

  10. Direct Synthesis of Hyperbranched Poly(acrylic acid-co-3-hydroxypropionate

    Directory of Open Access Journals (Sweden)

    Efkan Çatıker

    2015-01-01

    Full Text Available Hyperbranched poly(acrylic acid-co-3-hydroxypropionate (PAcHP was synthesized by base-catalyzed hydrogen transfer polymerization of acrylic acid through one step. The copolymers obtained through solution and bulk polymerization were insoluble in water and all organic solvents tried. Structural and compositional characterizations of hyperbranched PAcHP were performed by using FTIR, solid 13C-NMR, TGA, and titrimetric analysis. Acrylate fraction of the hyperbranched PAcHP obtained via bulk polymerization was determined as 60–65% by comparing TGA curves of hyperbranched PAcHP and pure poly(3-hydroxy propionate (PHP. However, analytical titration of the same sample revealed that acrylic acid units were about 47.3%. The results obtained from TGA and analytical titration were used to evaluate the chemical structure of the copolymer. Hyperbranched PAcHP exhibited hydrogel properties. Swelling behavior of the copolymer was investigated at a wide pH range and ionic strength. The dynamic swelling profiles of hyperbranched PAcHP exhibited a fast swelling behavior in the first hour and achieved the equilibrium state within 12 h in PBS. Depending on the conditions, the copolymers exhibited swelling ratios up to 2100%. As the copolymer has easily biodegradable propionate and versatile functional acrylic acid units, it can be used as not only biodegradable material in medical applications but also raw material in personal care commodities.

  11. Poly(ɛ-caprolactone) composites reinforced by biodegradable poly(3-hydroxybutyrate-co-3-hydroxyvalerate) fiber.

    Science.gov (United States)

    Ju, Dandan; Han, Lijing; Li, Fan; Chen, Shan; Dong, Lisong

    2014-06-01

    Biodegradable and biosourced poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) fiber was used as a reinforcing agent, and environment friendly poly(ɛ-caprolactone) (PCL) composites were prepared by melt compounding. The mechanical properties, rheological properties, and enzymatic degradation of the PCL composites were investigated in detail. With the addition of PHBV fibers, the PCL composites showed increased tensile yielding strength and modulus. Especially, the storage modulus from the results of dynamic mechanical analysis was increased significantly, suggesting that PCL was obviously reinforced by adding PHBV fibers. With increasing the PHBV fiber content, the complex viscosity and modulus of PCL increased, especially at low frequencies, indicating that a network structure was formed in the composites. The network structure resulted in evident solid-like response due to the restriction of the chain mobility of PCL matrix, which was further confirmed by the Han and Cole-Cole plots. The morphology, evaluated by scanning electron microscopy, indicated PCL and PHBV fiber were not highly incompatible and the interfacial adhesion was good, which was beneficial to the reinforcement effect. The biodegradability of the PCL was significantly promoted after composites preparation. Such studies are of great interest in the development of environment friendly composites from biodegradable polymers.

  12. NO and NO2 Sensing Properties of WO3 and Co3O4 Based Gas Sensors

    Directory of Open Access Journals (Sweden)

    Woosuck Shin

    2013-09-01

    Full Text Available Semiconductor-based gas sensors that use n-type WO3 or p-type Co3O4 powder were fabricated and their gas sensing properties toward NO2 or NO (0.5–5 ppm in air were investigated at 100 °C or 200 °C. The resistance of the WO3-based sensor increased on exposure to NO2 and NO. On the other hand, the resistance of the Co3O4-based sensor varied depending on the operating temperature and the gas species. The chemical states of the surface of WO3 or those of the Co3O4 powder on exposure to 1 ppm NO2 and NO were investigated by diffuse reflectance infrared Fourier transform (DRIFT spectroscopy. No clear differences between the chemical states of the metal oxide surface exposed to NO2 or NO could be detected from the DRIFT spectra.

  13. Galvanic displacement assembly of ultrathin Co3O4 nanosheet arrays on nickel foam for a high-performance supercapacitor

    Science.gov (United States)

    You, Yuxiu; Zheng, Maojun; Ma, Liguo; Yuan, Xiaoliang; Zhang, Bin; Li, Qiang; Wang, Faze; Song, Jingnan; Jiang, Dongkai; Liu, Pengjie; Ma, Li; Shen, Wenzhong

    2017-03-01

    High-performance supercapacitors are very desirable for many portable electronic devices, electric vehicles and high-power electronic devices. Herein, a facile and binder-free synthesis method, galvanic displacement of the precursor followed by heat treatment, is used to fabricate ultrathin Co3O4 nanosheet arrays on nickel foam substrate. When used as a supercapacitor electrode the prepared Co3O4 on nickel foam exhibits a maximum specific capacitance of 1095 F g‑1 at a current density of 1 A g‑1 and good cycling stability of 71% retention after 2000 cycling tests. This excellent electrochemical performance can be ascribed to the high specific surface area of each Co3O4 nanosheet that comprises numerous nanoparticles.

  14. Self-assembled biomimetic superhydrophobic CaCO3 coating inspired from fouling mineralization in geothermal water.

    Science.gov (United States)

    Wang, Gong G; Zhu, Li Q; Liu, Hui C; Li, Wei P

    2011-10-18

    Inspired from fouling self-mineralization in geothermal water, a novel biomimetic cactuslike CaCO(3) coating with superhydrophobic features is reported in this letter. The structure, morphologies, and phases of the CaCO(3) coating were characterized by X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, and infrared spectrophotometry. After prenucleation treatment, a continuous cactuslike CaCO(3) coating with hierarchical nano- and microstructures was self-assembled on stainless steel surfaces after immersion in simulated geothermal water at 50 °C for 48 h. After being modified with a low-surface-energy monolayer of sodium stearate, the as-prepared coating exhibited superhydrophobic properties with a water contact angle of 158.9° and a sliding angle of 2°. Therefore, this work might open up a new application field of geothermal resources and provide insight into designing multidimensional structures with functional applications, including superhydrophobic surfaces.

  15. Synthesis of Hierarchical (BiO)2CO3 Nanosheets Microspheres toward Efficient Photocatalystic Reduction of CO2 into CO

    Science.gov (United States)

    Yang, Huohai; Bai, Yang; Chen, Ting; Shi, Xian; Zhu, Yu-chuan

    2016-04-01

    In this paper, hierarchical (BiO)2CO3 nanosheets microspheres were synthesized with dry ice as carbon source, and characterized by X-ray diffraction (XRD) patterns, X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), high-resolution transmission electron microscopy (HRTEM) and UV-vis diffuse reflectance spectra (DRS). The photocatalytic results showed that (BiO)2CO3 display much higher photocatalytic activity than BiOCl and TiO2 for photocatalystic reduction of CO2 under UV-visible light. The photocatalytic mechanism study revealled that (BiO)2CO3 display better separation efficiency of photoinduced charge carriers due to the large interlayer spacing (1.3675 nm).

  16. Effect of Y2(CO3)3 and Surfactants on Electrorheological Performance of SiO2 Particle Materials

    Institute of Scientific and Technical Information of China (English)

    许明远; 马淑珍; 李淑新; 李俊然; 张少华; 魏宸官; 高松

    2004-01-01

    The SiO2 particle material has weak electrorheological (ER) activity. The ER performance of the SiO2 particles can be ameliorated after adsorbing Y2(CO3)3. In this paper, the effect of Y2(CO3)3 and different surfactants on the ER performance of the SiO2 particle materials is investigated. The results show that anionic or cationic surfactants maybe enhance the ER activity of SiO2 material, and nonionic surfactants cannot when surfactants are added during the process of the SiO2 particle preparation, only the anionic surfactant, AES, can enhance markedly the ER performance of the material. The surface area, pore volume and pore diameter of the particles were measured. The effect of Y2(CO3)3 and the surfactants on the microstructure of SiO2 materials and the relationship between ER effect and the microstructure are described.

  17. Origin of Capacity Fading in Nano-Sized Co3O4Electrodes: Electrochemical Impedance Spectroscopy Study

    Science.gov (United States)

    2008-01-01

    Transition metal oxides have been suggested as innovative, high-energy electrode materials for lithium-ion batteries because their electrochemical conversion reactions can transfer two to six electrons. However, nano-sized transition metal oxides, especially Co3O4, exhibit drastic capacity decay during discharge/charge cycling, which hinders their practical use in lithium-ion batteries. Herein, we prepared nano-sized Co3O4with high crystallinity using a simple citrate-gel method and used electrochemical impedance spectroscopy method to examine the origin for the drastic capacity fading observed in the nano-sized Co3O4anode system. During cycling, AC impedance responses were collected at the first discharged state and at every subsequent tenth discharged state until the 100th cycle. By examining the separable relaxation time of each electrochemical reaction and the goodness-of-fit results, a direct relation between the charge transfer process and cycling performance was clearly observed.

  18. Investigating the relation between CO (3-2) and far-infrared luminosities for nearby merging galaxies using ASTE

    Science.gov (United States)

    Michiyama, Tomonari; Iono, Daisuke; Nakanishi, Kouichiro; Ueda, Junko; Saito, Toshiki; Ando, Misaki; Kaneko, Hiroyuki; Yamashita, Takuji; Matsuda, Yuichi; Hatsukade, Bunyo; Kikuchi, Kenichi; Komugi, Shinya; Muto, Takayuki

    2016-09-01

    We present the new single-dish CO (3-2) emission data obtained toward 19 early-stage and 7 late-stage nearby merging galaxies using the Atacama Submillimeter Telescope Experiment (ASTE). Combining with the single-dish and interferometric data of galaxies observed in previous studies, we investigate the relation between the CO (3-2) luminosity (L^' }_CO(3-2)) and the far-infrared luminosity (LFIR) in a sample of 29 early-stage and 31 late-stage merging galaxies, and 28 nearby isolated spiral galaxies. We find that normal isolated spiral galaxies and merging galaxies have different slopes (α) in the log L^' }_CO(3-2)-log LFIR plane (α ˜ 0.79 for spirals and ˜1.12 for mergers). The large slope (α > 1) for merging galaxies can be interpreted as evidence for increasing star formation efficiency (SFE = L_FIR/L^' }_CO(3-2)) as a function of LFIR. Comparing our results with sub-kpc-scale local star formation and global starburst activity in the high-z universe, we find deviations from the linear relationship in the log L^' }_CO(3-2)-log LFIR plane for the late-stage mergers and high-z star-forming galaxies. Finally, we find that the average SFE gradually increases from isolated galaxies to merging galaxies and to high-z submillimeter galaxies/quasi-stellar objects. By comparing our findings with results from numerical simulations, we suggest that: (1) inefficient starbursts triggered by disk-wide dense clumps occur in the early stage of interaction, and (2) efficient starbursts triggered by central concentration of gas occur in the final stage. A systematic high spatial resolution survey of diffuse- and dense-gas tracers is the key to confirming this scenario.

  19. The effects of Co3O4 on the structure and unusual magnetism of LaCoO3

    Science.gov (United States)

    Durand, A. M.; Hamil, T. J.; Belanger, D. P.; Chi, S.; Ye, F.; Fernandez-Baca, J. A.; Abdollahian, Y.; Booth, C. H.

    2015-04-01

    Bulk LawCoO3 particles with w = 1.1, 1.0, 0.9, 0.8, and 0.7 were synthesized using starting materials with varying molar ratios of La2O3 and Co3O4. The resulting particles are characterized as LaCoO3 crystals interfaced with a crystalline Co3O4 phase. X-ray and neutron scattering data show little effect on the average structure and lattice parameters of the LaCoO3 phase resulting from the Co3O4 content, but magnetization data indicate that the amount of Co3O4 strongly affects the ferromagnetic ordering at the interfaces below TC ≈ 89 K. In addition to ferromagnetic long-range order, LaCoO3 exhibits antiferromagnetic behavior with an unusual temperature dependence. The magnetization for fields 20 Oe ⩽ H ⩽ 5 kOe is fit to a combination of a power law ((T - TC)/TC)β behavior representing the ferromagnetic long-range order and sigmoid-convoluted Curie-Weiss-like behavior representing the antiferromagnetic behavior. The critical exponent β = 0.63 ± 0.02 is consistent with 2D (surface) ordering. Increased Co3O4 correlates well to increased ferromagnetism. The weakening of the antiferromagnetism below T ≈ 40 K is a consequence of the lattice reaching a critical rhombahedral distortion as T is decreased for core regions far from the Co3O4 interfaces. We introduce a model that describes the ferromagnetic behavior of the interface regions and the unusual antiferromagnetism of the core regions.

  20. ANTS-anchored Zn-Al-CO3-LDH particles as fluorescent probe for sensing of folic acid

    Science.gov (United States)

    Liu, Pengfei; Liu, Dan; Liu, Yanhuan; Li, Lei

    2016-09-01

    A novel fluorescent nanosensor for detecting folic acid (FA) in aqueous media has been developed based on 8-aminonaphthalene-1,3,6-trisulfonate (ANTS) anchored to the surface of Zn-Al-CO3-layered double hydroxides (LDH) particles. The nanosensor showed high fluorescence intensity and good photostability due to a strong coordination interaction between surface Zn2+ ions of Zn-Al-CO3-LDH and N atoms of ANTS, which were verified by result of X-ray photoelectron spectroscopy (XPS). ANTS-anchored on the surface of Zn-Al-CO3-LDH restricted the intra-molecular rotation leading to ANTS-anchored J-type aggregation emission enhancement. ANTS-anchored Zn-Al-CO3-LDH particles exhibited highly sensitive and selective response to FA over other common metal ions and saccharides present in biological fluids. The proposed mechanism was that oxygen atoms of -SO3 groups in ANTS-anchored on the surface of Zn-Al-CO3-LDH were easily collided by FA molecules to form potential hydrogen bonds between ANTS-anchored and FA molecules, which could effectively quench the ANTS-anchored fluorescence. Under the simulated physiological conditions (pH of 7.4), the fluorescence quenching was fitted to Stern-Volmer equation with a linear response in the concentration range of 1 μM to 200 μM with a limit of detection of 0.1 μM. The results indicate that ANTS-anchored Zn-Al-CO3-LDH particles can afford a very sensitive system for the sensing FA in aqueous solution.

  1. Temperature dependence of the spin state of a Co3+ Ion in RCoO3 ( R = La, Gd) cobaltites

    Science.gov (United States)

    Babkin, R. Yu.; Lamonova, K. V.; Orel, S. M.; Ovchinnikov, S. G.; Pashkevich, Yu. G.

    2014-06-01

    Changes in the spin state of Co3+ ions in LaCoO3 and GdCoO3 compounds are studied through the use of the temperature dependence of the magnetic susceptibility and the modified crystal field theory. It is shown that the spin subsystem of Co3+ ions in LaCoO3 and GdCoO3 undergoes the spin-crossover type transition between the high-spin ( S = 2) and low-spin ( S = 0) states without any contribution of the intermediate-spin state ( S = 1).

  2. Oxidation of Fe–22Cr Coated with Co3O4: Microstructure Evolution and the Effect of Growth Stresses

    DEFF Research Database (Denmark)

    Hansson, Anette Nørgaard; Burriel, Monica; Garcia, Gemma;

    2007-01-01

    diffraction, electron microscopy, and energy dispersive X-ray spectroscopy. Cr2O3 developed in between the Co3O4 coating and the alloy, while alloying elements of the substrate were incorporated into the coating. Particular attention was devoted to possible sources of growth stresses and the effect......The oxidation behavior of a commercially available Fe–22Cr alloy coated with a Co3O4 layer by metal organic—chemical vapor deposition was investigated in air with 1% H2O at 1,173 K and compared to the oxidation behavior of the non-coated alloy. The oxide morphology was examined with X-ray...

  3. Room-temperature ferromagnetism in the mixtures of the TiO2 and Co3O4 powders

    Science.gov (United States)

    Serrano, A.; Pinel, E. Fernandez; Quesada, A.; Lorite, I.; Plaza, M.; Pérez, L.; Jiménez-Villacorta, F.; de La Venta, J.; Martín-González, M. S.; Costa-Krämer, J. L.; Fernandez, J. F.; Llopis, J.; García, M. A.

    2009-04-01

    We report here the observation of ferromagnetism (FM) at 300 K in mixtures of TiO2 and Co3O4 powders despite the antiferromagnetic and diamagnetic characters of both oxides, respectively. The ferromagnetic behavior is found in the early stages of reaction and only for TiO2 in anatase structure; no FM is found for identical samples prepared with rutile- TiO2 . Optical spectroscopy and x-ray absorption spectra confirm a surface reduction of octahedral Co+3→Co+2 in the mixtures which is in the origin of the observed magnetism.

  4. Supercapacitor electrode with a homogeneously Co3O4-coated multiwalled carbon nanotube for a high capacitance.

    Science.gov (United States)

    Tao, Li; Shengjun, Li; Bowen, Zhang; Bei, Wang; Dayong, Nie; Zeng, Chen; Ying, Yan; Ning, Wan; Weifeng, Zhang

    2015-01-01

    Cobalt oxide (Co3O4) was homogeneously coated on multiwalled carbon nanotube through a simple chemical deposition method and employed in supercapacitor electrodes. SEM image indicated the uniform distribution of Co3O4 nanoparticles on the surface of the multiwalled carbon nanotube. A maximum specific capacitance of 273 Fg(-1) was obtained at the charge-discharge current density of 0.5 Ag(-1). After 500 cycles of continuous charge-discharge process, about 88% of the initial capacity could be retained.

  5. The synthesis and pH-dependent behaviour of Re(CO)3 conjugates with diimine phenolic ligands

    OpenAIRE

    Chanawanno, Kullapa; James T. Engle; Le, Kevin X.; Herrick, Richard S.; Ziegler, Christopher J.

    2013-01-01

    In this report we present a study of a series of Re(CO)3 pyridineimine complexes with pendant phenol groups. We investigated the effects of the position of the phenol hydroxyl group (para, meta or ortho to the imine) on the steric and electronic characteristics of a series of Re(CO)3X(pyca-C6H4OH) compounds, where X = Cl, Br and pyca = pyridine-2-carbaldehyde imine. These compounds can be generated either via ligand synthesis followed by metal chelation (compound 4) or via a one-pot method (c...

  6. Co3O4 mirobelts: Preparation with the electrospinning technique and its investigation in peroxidase-like activity

    Science.gov (United States)

    Sun, Haiyan; Zhu, Weiyue

    2017-03-01

    Co3O4 microbelts were prepared with cobalt nitrate and PVP as raw materials by an electrospinning technique combined with subsequent calcination. The belt-like Co3O4 was characterized by XRD, SEM, TEM, FT-IR and its N2 adsorption-desorption behavior was measured. In addition, its peroxidase-like activity was investigated with H2O2 and 3,3‧,5,5‧-tetramethylbenzidine as substrates, and the product with the highest specific area exhibits the best catalytic activity and stability.

  7. Penelitian pembuatan komponen PVC untuk bahan bangunan (enternit PVC dengan variasi filler serat batang pisang dan CaCO3

    Directory of Open Access Journals (Sweden)

    Siti Rochani

    1987-12-01

    Full Text Available This research is an experiment which use plastic material for making enternit. The plastic material is made of PVC resin 100 phr. by adding ingredients DOP 35 phr., EPO 5 phr., BaCdZn 3.5 phr., Stearic Acid 0.75 phr., CaCO3 varied 50-90 phr., and fibre of banana stem 20-40 phr. The experiment result proved that the PVC plastic material can made enternit sheet. The optimum value of physical properties is achiven by the PVC compound which using CaCO3 90 phr. and banana stem 40 phr.

  8. Preparation of core-shell structured Co3O4 by hydrothermal method and their electrochemical properties%核壳结构Co3O4水热法制备及其电化学性能

    Institute of Scientific and Technical Information of China (English)

    王兴磊; 何晓燕; 胡云霞; 欧阳艳

    2012-01-01

    以硝酸钴为原料,柠檬酸三钠为模板,六次甲基四胺为成沉淀剂水热制备了核壳结构Co3O4,X射线衍射(XRD)、扫描电镜(SEM)测试表明,柠檬酸三钠的加入使制备的Co3O4呈现核壳状结构,循环伏安等电化学研究表明该材料的电化学电容性能较好,单电极比电容达到333 F/g.%The core-shell structured Co3O4 was synthesized by hydrothermal method with cobaltous nitrate [Co(NO3)3] and hexamethylenetetramine (C6H12N4) as raw materials, and sodium citrate (C6H5Na2O7) as template. The XRD (X-ray diffraction) and SEM (scan electron microscope) results show that the prepared Co3O4 has the core-shell structure due to the addition of C6H5Na3O7. The electrochemical tests show that the material has a good capacitance, and the specific capacitance of single electrode is up to 333 F/g.

  9. Heterogeneous uptake of gaseous nitric acid on dolomite (CaMg(CO3)2) and calcite (CaCO3) particles: a Knudsen cell study using multiple, single, and fractional particle layers.

    Science.gov (United States)

    Johnson, Elizabeth R; Sciegienka, Joanna; Carlos-Cuellar, Sofia; Grassian, Vicki H

    2005-08-11

    In this study, the heterogeneous uptake of gaseous nitric acid on dolomite, CaMg(CO3)2, and calcite, CaCO3, particles under dry conditions at 296 K was investigated. A Knudsen cell reactor was used to measure heterogeneous uptake coefficients for these reactions. Several different experiments were performed including those on many, single, and fractional layers of particles. For experiments using multiple particle layers, the Knudsen cell data were modeled to take into account gas diffusion into the underlying layers of the sample. From this analysis, initial heterogeneous uptake coefficients, gamma(o,t), were determined to be (5 +/- 2) x 10(-4) and (2 +/- 1) x 10(-3), for dolomite and calcite, respectively, at a nitric acid concentration of 6.5 x 10(10) molecules cm(-3). For experiments that employed single or fractional particle layers, the initial heterogeneous uptake coefficient was analyzed using a recent method described in the literature. Values of the initial heterogeneous uptake coefficient using this analysis were in agreement with the above analysis and determined to be (7 +/- 4) x 10(-4) and (2 +/- 0.4) x 10(-3) for CaMg(CO3)2 and CaCO3, respectively. In addition, these results are compared to previous literature values.

  10. 复合水滑石热稳定剂对PVC热稳定性能的影响%Effect of MgAl-CO_3-LDH/ZnAl-CO_3-LDH composites on thermal stability of PVC

    Institute of Scientific and Technical Information of China (English)

    刘庆艳; 杨占红; 易师

    2010-01-01

    采用共沉淀法制备镁铝水滑石和锌铝水滑石,采用XRD、FT-IR对其进行表征,同时将其按不同比例进行复配应用到聚氯乙烯(PVC)中.利用静态热老化法研究复合水滑石稳定剂在聚氯乙烯中的热稳定性能.结果表明:合成的镁铝水滑石和锌铝水滑石结晶度高,结构规整;镁铝水滑石和锌铝水滑石复配物的热稳定性能优于单一镁铝水滑石、锌铝水滑石,其最佳复配摩尔比为x(MgAl-CO_3-LDH)-x(ZnAl-CO_3-LDH)=1-0.7.当该复配物与同样金属含量的ZnMgAl-CO_3-LDH(x(Zn)-x(Mg)-x(Al)=0.7-1-1.7)相比时,前者热稳定性能更好.另外,制备该复配物的工艺较制备ZnMgAl-CO_3-LDH的工艺更简单.

  11. Preparation of CoO and Co_3O_4 Thin Films Deposited by Reactive PLD%反应激光脉冲沉积法制备CoO和Co_3O_4薄膜

    Institute of Scientific and Technical Information of China (English)

    季振国; 吴家亮; 曹虹; 席俊华; 李红霞

    2011-01-01

    利用反应脉冲激光沉积法,以金属钴为靶材,通过改变衬底温度、反应气体氧气的流量等工艺参数,先后在玻璃衬底上成功制备了CoO薄膜以及Co3O4薄膜。通过X射线衍射(XRD)、X射线光电子能谱(XPS)、紫外-可见光吸收光谱(UV-Vis)研究了沉积工艺参数对沉积薄膜的晶体结构和光学特性的影响。结果表明,当氧气流量小于15sccm时,沉积的薄膜为岩盐矿结构的CoO,而当氧气流量大于15sccm时,沉积的薄膜为尖晶石矿结构的Co3O4。通过对紫外-可见吸收光谱的数据分析,证明CoO和Co3O4薄膜均为间接能带结构,禁带宽度分别为0.82eV和1.21eV。%CoO and Co3O4 thin films have been deposited on glass substrates at different temperatures and with various oxygen flow rates by reactive pulsed laser deposition(PLD) techniques.High purity metallic Co disk was used as the target material,and high purity oxygen was used as the reactive gas.X-ray diffractometry(XRD),X-ray photoelectron spectroscopy(XPS),and UV-visible spectrometry were applied to characterize the crystalline phases of the deposited films.Results show that when the oxygen flow rate is less than 15sccm,the deposited films are rock salt type CoO,while films deposited at an oxygen flow rate greater than 15sccm,the deposited films are spinel type Co3O4.The indirect band structures of both the CoO and Co3O4 phases are proved by UV-Vis absorbance spectra,with bandgaps of 0.82eV for CoO and 1.21eV for Co3O4,respectively.

  12. Preparation and magnetic property of WO3-Co3 O4 composite oxides%WO3-Co3O4复合氧化物的制备及磁学性质

    Institute of Scientific and Technical Information of China (English)

    隋春红; 龚剑

    2016-01-01

    Objective To study the relations between crystal and magnetism during the preparation of composite ox-ides by different inorganic compounds. Methods The PVA/α2-K8 P2 W17 CoO61 and PVA/KCl,( NH4 ) 6 H2 W12 O40 ,Co ( NO3 ) 2 were chosen as raw materials to prepare the composite oxides by using the electrospinning and calcinations technique. Results Scanning electron microscope ( SEM ) photographs and X-ray diffraction ( XRD ) indicated that nanoplates and hexagonal system tungsten oxide ( WO3 )-cobaltosic oxide ( Co3 O4 ) composite oxides were ob-tained. The magnetic properties appeared the ferromagnetic couples. While,chosing inorganic compounds as raw mate-rials,the nanofibers morphology and hexagonal and triclinic system WO3-Co3O4 were obtained. The magnetic properties appeared the antiferromagnetic couples. Conclusion Different crystal WO3 has significant effect on magnetism of Co3 O4 .%目的 采用不同的无机原料制备复合型氧化物,考察晶系与磁性的关系. 方法 选取 PVA/α2-K8 P2 W17 CoO61和PVA/KCl、( NH4 ) 6 H2 W12 O40、Co( NO3 ) 2 为原料经过高压静电纺丝和高温焙烧方法,制备WO3-Co3 O4 复合氧化物. 结果 从扫描电镜照片( SEM)可以看出,杂多酸盐为母体经过高温焙烧后得到了纳米片形貌的复合氧化物,X-射线粉末衍射( XRD)测试结果为六方晶相WO3-Co3 O4 的复合氧化物,磁学性质为铁磁性耦合;选取普通无机化合物为原料获得纤维形貌的复合氧化物,其晶态为六方和三斜晶相共混的WO3-Co3 O4的复合氧化物,表现为反铁磁性耦耦合. 结论 不同晶系的WO3 对Co3 O4 的磁性有显著的影响.

  13. Synthesis zeolite from Na2CO3 activated flyash for copper ions removal%Na2 CO3活化粉煤灰合成沸石及去除Cu2+性能

    Institute of Scientific and Technical Information of China (English)

    曹月坤; 陈文艺; 邓慧; 白云; 张志强

    2015-01-01

    Zeolites were synthesized through high temperature melting method,hydrothermal method and hydrothermal assisted pressure method based on fly ash as a matrix material with Na2 CO3 as alkaline acti-vating reagent,and their removal effect of copper ions were compared. Influence of hydrothermal tempera-ture,autogenous pressure,Na2 CO3 concentration,liquid to solid ratio,hydrothermal time and other factors on Na2 CO3 alkaline activation of fly ash were investigated. Results showed that the hydrothermal assisted pressure synthesis of zeolite adsorption of copper ions was the best,removal rate for 200 mg/L copper ion reached 92% when temperature was 90 ℃,self-generated pressure was 0. 038 MPa,Na2 CO3 was 2. 0 mol/L,liquid-solid ratio was 10∶1 and hydrothermal time was 2 h. XRD and SEM description sugges-ted that synthesic zeolite was NaP.%以粉煤灰为基质材料,Na2 CO3为碱性活化试剂,比较了高温熔融法、水热法和加压水热法合成沸石对铜离子的去除效果。研究了水热温度及压力、Na2 CO3浓度、液固比、水热时间等因素对Na2 CO3碱性活化粉煤灰的影响。结果表明,加压水热法合成的沸石对铜离子的吸附效果最好,温度90℃,自生压0.038 MPa,Na2 CO32.0 mol/L,液固比10∶1、水热时间2 h时合成的沸石对初始浓度200 mg/L的铜离子的去除率可达92%,XRD表征说明合成的沸石为NaP型。

  14. Texturization of monocrystalline silicon with Na2CO3/NaHCO3 solution%使用Na2CO3/NaHCO3体系进行单晶硅制绒

    Institute of Scientific and Technical Information of China (English)

    张启华; 汤俊琪; 满石清

    2013-01-01

    The conversion efficiency of solar cell could be improved by reducing the reflectivity of solar panel by texturing the panel surface. In this study, the surfaces of monocrystalline silicon chips, a common type of solar panel, were texturized with Na2CO3, NaHCO3 and Na2CO3/NaHCO3 solution. The morphology and reflectivity of the texturized surfaces were characterized with scanning electron microscope (SEM) and UV-Vis spectrophotometer, respectively, and the effects of solution concentration, solution composition and reaction time on the reflectivity of the texturized surfaces were studied. The results show that a texturized surface with a reflectivity of 15.22% can be prepared by immersing the silicon chip in the Na2CO3/NaHCO3 solution containing 12wt% Na2CO3 and 1.2wt% for 10 minutes at 85 ℃.%通过单晶硅表面制绒可以降低太阳能电池面板对光的反射率进而提高电池的转化效率.利用Na2CO3、NaHCO3和Na2CO3/NaHCO3溶液进行了单晶硅表面制线,并利用扫描电子显微镜和紫外/可见光光度计对所得绒面的形貌及反色率分别进行了分析.研究了溶液浓度、溶液组成及反应时间等因素对所制单晶硅绒面反射率的影响.结果表明:在Na2CO3∶NaHCO3质量比为10∶1,反应温度为85℃,反应时间为10 min时,可获得反射率为15.22%的绒面.

  15. Splice variants of perlucin from Haliotis laevigata modulate the crystallisation of CaCO3.

    Directory of Open Access Journals (Sweden)

    Tanja Dodenhof

    Full Text Available Perlucin is one of the proteins of the organic matrix of nacre (mother of pearl playing an important role in biomineralisation. This nacreous layer can be predominately found in the mollusc lineages and is most intensively studied as a compound of the shell of the marine Australian abalone Haliotis laevigata. A more detailed analysis of Perlucin will elucidate some of the still unknown processes in the complex interplay of the organic/inorganic compounds involved in the formation of nacre as a very interesting composite material not only from a life science-based point of view. Within this study we discovered three unknown Perlucin splice variants of the Australian abalone H. laevigata. The amplified cDNAs vary from 562 to 815 base pairs and the resulting translation products differ predominantly in the absence or presence of a varying number of a 10 mer peptide C-terminal repeat. The splice variants could further be confirmed by matrix-assisted laser desorption ionisation time of flight mass spectrometry (MALDI-ToF MS analysis as endogenous Perlucin, purified from decalcified abalone shell. Interestingly, we observed that the different variants expressed as maltose-binding protein (MBP fusion proteins in E. coli showed strong differences in their influence on precipitating CaCO3 and that these differences might be due to a splice variant-specific formation of large protein aggregates influenced by the number of the 10 mer peptide repeats. Our results are evidence for a more complex situation with respect to Perlucin functional regulation by demonstrating that Perlucin splice variants modulate the crystallisation of calcium carbonate. The identification of differentially behaving Perlucin variants may open a completely new perspective for the field of nacre biomineralisation.

  16. The influence of electron discharge and magnetic field on calcium carbonate (CaCO3) precipitation

    Science.gov (United States)

    Putro, Triswantoro; Endarko

    2016-04-01

    The influences of electron discharge and magnetic field on calcium carbonate (CaCO3) precipitation in water have been successfully investigated. The study used three pairs of magnetic field 0.1 T whilst the electron discharge was generated from television flyback transformer type BW00607 and stainless steel SUS 304 as an electrode. The water sample with an initial condition of 230 mg/L placed in the reactor with flow rate 375 mL/minutes, result showed that the electron discharge can be reduced contain of calcium carbonate the water sample around 17.39% within 2 hours. Meanwhile for the same long period of treatment and flow rate, around 56.69% from initial condition of 520 mg/L of calcium carbonate in the water sample can be achieved by three pairs of magnetic field 0.1 T. When the combination of three pairs of magnetic field 0.1 T and the electron discharge used for treatment, the result showed that the combination of electron discharge and magnetic field methods can be used to precipitate calcium carbonate in the water sample 300 mg/L around 76.66% for 2 hours of treatment. The study then investigated the influence of the polar position of the magnetic field on calcium carbonate precipitation. Two positions of magnetic field were tested namely the system with alternated polar magnetics and the system without inversion of the polar magnetics. The influence of the polar position showed that the percentage reduction in levels of calcium carbonate in the water sample (360 mg/L) is significant different. Result showed that the system without inversion of the polar magnetics is generally lower than the system with alternated polar magnetics, with reduction level at 30.55 and 57.69%, respectively.

  17. Sol-Gel Auto-Combustion Synthesis of Co3O4Nanoparticles%溶胶-凝胶自蔓延法制备纳米Co3O4的研究

    Institute of Scientific and Technical Information of China (English)

    赵清清; 王静; 杨金萍; 戚爱荣

    2015-01-01

    采用溶胶-凝胶自蔓延燃烧法制备锂离子电池纳米Co3O4负极材料,利用XRD、SEM和充放电测试等手段表征了不同的原料比和热处理温度对材料的结构、颗粒形貌和电化学性能的影响。实验表明:硝酸钴和柠檬酸摩尔比为1∶2,400℃空气气氛下热处理制备的Co3O4材料表现出良好的电化学性能。首次可逆容量为1121.4 mAhg-1,循环30次后可逆容量仍能高达865.3 mAhg-1,容量保持率约为77.2%。%The Co3O4anode material was synthesized via the sol-gel auto-combustion method. The effects of the molar ratio of raw materials and the heat-treatment temperature on the phase composition, the particle morphology, structure and the electrochemical performance of the prepared Co3O4 composites were investigated by SEM, XRD and charge-discharge tests. The result shows that the Co3O4 nanoparticles prepared at the cobalt nitrate/citric acid molar ratio of 1:2 by heat treatment at 400℃ in air exhibit excellent speciifc capacity. The reversible capacity is 1121.4 mAhg-1 after the ifrst cycle and remains 865.3 mAhg-1 after 30 cycles, about 77.2% of the initial reversible capacity.

  18. Effect of Oleic Acid-modified Nano-CaCO3 on the Crystallization Behavior and Mechanical Properties of Polypropylene%油酸修饰纳米CaCO3对PP结晶行为和力学性能的影响

    Institute of Scientific and Technical Information of China (English)

    申屠宝卿; 李继鹏; 翁志学

    2006-01-01

    Oleic acid (OA)-modified CaCO3 nanoparticles were prepared using surface modification method. Infrared spectroscopy (IR) was used to investigate the structure of the modified CaCO3 nanoparticles, and the result showed that OA attached to the surface of CaCO3 nanoparticles with the ionic bond. Effect of OA concentration on the dispersion stability of CaCO3 in heptane was also studied, and the result indicated that modified CaCO3 nanoparticles dispersed in heptane more stably than unmodified ones. The optimal proportion of OA to CaCO3 was established. The effect of modified CaCO3 nanoparticles on crystallization behavior of polypropylene (PP) was studied by means of DSC. It was found that CaCO3 significantly increased the crystallization temperature, crystallization degree and crystallization rate of PP, and the addition of modified CaCO3 nanoparticles can lead to the formation of β-crystal PP. Effect of the modified CaCO3 content on mechanical properties of PP/CaCO3 nanocomposites was also studied. The results showed that the modified CaCO3 can effectively improve the mechanical properties of PP. In comparison with PP, the impact strength of PP/CaCO3 nanocomposites increased by about 65% and the flexural strength increased by about 20%.

  19. Steam reforming of ethanol over Co3O4–Fe2O3 mixed oxides

    KAUST Repository

    Abdelkader, A.

    2013-05-03

    Co3O4, Fe2O3 and a mixture of the two oxides Co-Fe (molar ratio of Co3O4/Fe 2O3 = 0.67 and atomic ratio of Co/Fe = 1) were prepared by the calcination of cobalt oxalate and/or iron oxalate salts at 500 C for 2 h in static air using water as a solvent/dispersing agent. The catalysts were studied in the steam reforming of ethanol to investigate the effect of the partial substitution of Co3O4 with Fe2O 3 on the catalytic behaviour. The reforming activity over Fe 2O3, while initially high, underwent fast deactivation. In comparison, over the Co-Fe catalyst both the H2 yield and stability were higher than that found over the pure Co3O4 or Fe 2O3 catalysts. DRIFTS-MS studies under the reaction feed highlighted that the Co-Fe catalyst had increased amounts of adsorbed OH/water; similar to Fe2O3. Increasing the amount of reactive species (water/OH species) adsorbed on the Co-Fe catalyst surface is proposed to facilitate the steam reforming reaction rather than decomposition reactions reducing by-product formation and providing a higher H2 yield. © Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  20. Reinforcing and Toughening Effects of Bamboo Pulp Fiber on Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Fiber Composites.

    Science.gov (United States)

    Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/bamboo pulp fiber composites were melt-compounded and injection-molded. Tensile, impact and dynamic mechanical properties of the composites were studied. In contrast to many other short natural fiber reinforced biocomposites which demonstrate decre...

  1. Nanospheres of alginate prepared through w/o emulsification and internal gelation with nanoparticles of CaCO3

    NARCIS (Netherlands)

    Paques, J.P.; Sagis, L.M.C.; Rijn, van C.J.M.; Linden, van der E.

    2014-01-01

    Gelled nanospheres of alginate are prepared through a single step technique involving emulsification and gelation. CaCO3 nanoparticles, together with glucono delta-lactone (GDL), are dispersed in an alginate solution, which is subsequently dispersed in an oil phase and followed by gelation of the al

  2. Net loss of CaCO3 from coral reef communities due to human induced seawater acidification

    Directory of Open Access Journals (Sweden)

    K. S. Rodgers

    2009-02-01

    Full Text Available Acidification of seawater owing to oceanic uptake of atmospheric CO2 originating from human activities such as burning of fossil fuels and land-use changes has raised serious concerns for its adverse effects on corals, coral reefs and carbonate communities in general. Here we demonstrate a transition from net accumulation towards net loss of calcium carbonate (CaCO3 material owing to decreased calcification and increased carbonate dissolution from replicated subtropical coral reef communities (n=3 incubated in continuous-flow mesocosms subject to present and future seawater conditions. The calcifying community was dominated by the coral Montipora capitata. Daily average community calcification or Net Ecosystem Calcification (NEC = CaCO3 production – dissolution was positive at 4.5 mmol CaCO3 m−2 h−1 under ambient seawater pCO2 conditions as opposed to negative at −0.1 mmol CaCO3 m−2 h−1 under seawater conditions of double the ambient pCO2. These experimental results provide support for the conclusion that some net calcifying communities could become subject to net dissolution in response to anthropogenic ocean acidification within this century.

  3. Investigation of Co3O4 nanorods supported Pd anode catalyst for methanol oxidation in alkaline solution

    Institute of Scientific and Technical Information of China (English)

    Yanbiao Ren; Shichao Zhang∗; Hua Fang; Xin Wei; Puheng Yang

    2014-01-01

    A Co3 O4 nanorod supported Pd electro-catalyst for the methanol electro-oxidation (MEO) has been fabricated by the combination of hydrother-mal synthesis and microwave-assisted polyol reduction processes. The crystallographic property and microstructure have been characterized using XRD, SEM and TEM. The results demonstrate that Pd nanoparticles (PdNPs) with a narrow particle size distribution (3−5 nm) are uni-formly deposited onto the surface of Co3O4 nanorods. Electrochemical measurements show that this catalyst having a larger electrochemically active surface area and a more negative onset-potential exhibits enhanced catalytic activity of 504 mA/mg Pd for MEO comparing with the Pd/C catalyst (448 mA/mg Pd). The dependency of logI against logv reveals that MEO on Pd-Co3O4 electrode is under a diffusion control. Electrochemical impedance spectroscopy (EIS) measurement agrees well with the CV results. The minimum charge transfer resistance of MEO on Pd-Co3 O4 is observed at−0.05 V, which coincides with the potential of MEO peak.

  4. Promotion effect of palladium on Co3O4 incorporated within mesoporous MCM-41 silica for CO Oxidation

    Science.gov (United States)

    Hassan, Hassan M. A.; Betiha, Mohamed A.; Elshaarawy, Reda F. M.; Samy El-Shall, M.

    2017-04-01

    Co3O4 incorporated within mesoporous MCM-41 silica have been successfully synthesized and promoted with Pd nanoparticles through a microwave irradiation (MWI) approach. Powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), N2-physisorped, X-ray photoelectron spectroscopy (XPS), temperature program reduction of hydrogen (H2-TPR), temperature program desorption of oxygen (O2-TPD) and high resolution transmission electron microscopy (HRTEM) were adapted to characterize these prepared catalysts. Carbon monoxide oxidation as a model reaction was then used to assess the catalytic performance of these materials. In the light of H2-TPR and XPS results, revealed that the coexisting of Co3+ and Co2+ species as well as surface Co3+/Co2+ ratio within the hexagonal mesoporous of MCM-41, could create an ideal environment to accomplish most extreme catalytic activity. On the other hand, the enhanced CO oxidation by Pd nanoparticles deposition has been explained in the light of the enhancement of the redox ability and tuning the electronic structure of Co3O4, which improved the O2 activation and reduced the adsorption ability of CO simultaneously, which significantly boosted the catalytic performance of CO oxidation. This work provides insights into factors that could lead to improved low temperature CO oxidation performance in Pd-based catalysts.

  5. Fundamental insight in soot oxidation over a Ag/Co3O4 catalyst by means of Environmental TEM

    DEFF Research Database (Denmark)

    Gardini, Diego; Christiansen, J. M.; Jensen, Anker Degn;

    A novel Ag/Co3O4 catalyst for low-temperature soot oxidation has been studied by means of environmental TEM in order to get fundamental insight in the oxidation mechanism. Soot particles generated in diesel engines are responsible for respiratory diseases, lung cancer and affect the climate both...

  6. High-performance all-solid state asymmetric supercapacitor based on Co3O4 nanowires and carbon aerogel

    Science.gov (United States)

    Liu, Weiwei; Li, Xin; Zhu, Menghua; He, Xiong

    2015-05-01

    An all-solid state asymmetric supercapacitor has been fabricated using carbon aerogel (CA) microspheres as the negative electrode and Co3O4 nanowires on nickel foam (Co3O4-NF) as the positive electrode separated by PVA-KOH membrane as the electrolyte. For the desirable porous structure, high specific capacitance and rate capability of CA and Co3O4-NF, broader potential window of the two electrodes, no binder and conductive agent added, the asymmetric supercapacitor can be cycled reversibly in a wide potential window of 0-1.5 V with an energy density of 17.9 Wh kg-1 at a power density of 750 W kg-1. The energy density of the asymmetric supercapacitor is significantly improved in comparison with those of the symmetric supercapacitors based on CA (6.28 Wh kg-1) and Co3O4-NF (2.42 Wh kg-1). The asymmetric supercapacitor can also deliver a high energy density of 10.44 Wh kg-1, even at a high power density of 7.5 kW kg-1. In addition, the asymmetric device shows good stability with approximately 85% of its initial capacitance after 1000 cycles.

  7. Nanosheet-based hierarchical Ni(2)(CO(3))(OH)(2) microspheres with weak crystallinity for high-performance supercapacitor.

    Science.gov (United States)

    Zhu, Guoxing; Xi, Chunyan; Shen, Mengqi; Bao, Chunlin; Zhu, Jun

    2014-10-08

    Three-dimensionally hierarchical oxide/hydroxide materials have recently attracted increasing interest by virtue of their exciting potential in electrochemical energy conversion and storage. Herein, hierarchical Ni2(CO3)(OH)2 microspheres assembled from ultrathin nanosheets were successfully synthesized by a one-pot/one-step hydrothermal route. In this method, common nickel salts and urea were selected as raw materials. The influence of urea concentration on the final product was studied. The hierarchical Ni2(CO3)(OH)2 microspheres show weak crystallinity and contain crystalline water. It was found that they exhibit excellent rate capacity when used as supercapacitor electrode. Under current density of 0.5 and 10 A/g, the optimized Ni2(CO3)(OH)2 electrode with loading density of 5.3 mg/cm(2) exhibited specific capacitances of 1178 and 613 F/g with excellent cycling stability. The excellent electrochemical property is possibly attributed to the intrinsic nature of Ni2(CO3)(OH)2, the ultrathin thickness of nanosheet units, and the sufficient space available to interact with the electrolyte. This facile synthesis strategy and the good electrochemical properties indicate that hydroxycarbonates are promising materials for supercapacitor application. This study suggests a large library of materials for potential application in energy storage systems.

  8. The CaCO3-Fe interaction: Kinetic approach for carbonate subduction to the deep Earth's mantle

    Science.gov (United States)

    Martirosyan, N. S.; Yoshino, T.; Shatskiy, A.; Chanyshev, A. D.; Litasov, K. D.

    2016-10-01

    The CaCO3-Fe0 system, as a model for redox reactions between carbonates and reduced lithologies at the slab-mantle interface during subduction or at core-mantle boundary, was investigated systematically at temperatures from 650 to 1400 °C and pressures from 4 to 16 GPa using multianvil apparatus. CaCO3 reduction via reaction: 3 CaCO3 (aragonite) + 13 Fe0 (metal) = Fe7C3 (carbide) + 3 CaFe2O3 (Ca-wüstite) was observed. The thickness of the reaction-product layer (Δx) increases linearly with the square root of time in the time-series experiments (t), indicating diffusion-controlled process. The reaction rate constant (k = Δx2/2t) is log-linear relative to 1/T. Its temperature dependences was determined to be k [m2/s] = 2.1 × 10-7exp(-162[kJ/mol]/RT) at 4-6 GPa and k [m2/s] = 2.6 × 10-11exp(-65[kJ/mol]/RT) at 16 GPa. The sluggish kinetics of established CaCO3-Fe0 interaction suggests that significant amount of carbonates could survive during subduction from metal saturation boundary near 250 km depth down to the transition zone and presumably to the lower mantle if melting of carbonates is not involved.

  9. Influence of Mg2+ on Initial Stages of CaCO3 Scale Formed on Metal Surface

    Institute of Scientific and Technical Information of China (English)

    CHEN Tao; Anne Neville; YUAN Ming-dong

    2004-01-01

    Magnesium ions, which exist in formation water and injection water under downhole conditions in the oil and gas production industry, are a key determinant in the CaCO3 scale formation. Many studies have focused their attention on the effect of magnesium on the kinetics, the morphology and the content of Mg in the CaCOs scale. Little attention has been paid to the effect of Mg2+ on the initial stages of CaCO3 formation on a metal surface. In this study, an electrochemical technique was used to study the influence of Mg2+ on the initial stages of CaCO3 scale formed on a metal surface. With this electrochemical technique, the reduction of the dissolved oxygen in an analysis solution is considered on the surface of a rotating disk electrode (RDE) under potentiostatic control. The rate of oxygen reduction on the surface of the RDE enables the extent of surface coverage of scale to be assessed. With this electrochemical technique, a new insight into the effect of Mg2+ on CaCO3 scale formed on a metal surface is given.

  10. Room-temperature CO Thermoelectric Gas Sensor based on Au/Co3O4 Catalyst Tablet

    Science.gov (United States)

    Sun, L.; Luan, W. L.; Wang, T. C.; Su, W. X.; Zhang, L. X.

    2017-02-01

    A carbon monoxide (CO) thermoelectric (TE) gas sensor was fabricated by affixing a Au/Co3O4 catalyst tablet on a TE film layer. The Au/Co3O4 catalyst tablet was prepared by a co-precipitation and tablet compression method and its possible catalytic mechanism was discussed by means of x-ray diffraction, field emission scanning electron microscopy, high resolution transmission electron microscopy, x-ray photoelectron spectroscopy, temperature-programmed reduction of hydrogen, Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller analysis. The optimal catalyst, with a Au content of 10 wt%, was obtained at a calcination temperature between 200 and 300 °C. The small size of the Au nanoparticles, high specific surface, the existence of Co3+ and water-derived species contributed to high catalytic activity. Based on the optimal Au/Co3O4 catalyst tablet, the CO TE gas sensor worked at room temperature and showed a response voltage signal (ΔV) of 23 mV, high selectivity among hydrogen and methane, high stability, and a fast response time of 106 s for 30 000 ppm CO/air. In addition, a CO concentration in the range of 5000-30 000 ppm could obviously be detected and exhibited a linear relationship with ΔV. The CO TE gas sensor provides a promising option for the detection of CO gas at room temperature.

  11. Prevalence and behavioural risks for HIV and HCV infections in a population of drug users of Dakar, Senegal: the ANRS 12243 UDSEN study

    Directory of Open Access Journals (Sweden)

    Annie Leprêtre

    2015-05-01

    Full Text Available Objectives: Data on the extent of drug use and associated HIV, hepatitis C and hepatitis B infection in West Africa are lacking. The objectives of ANRS12244 UDSEN study were to estimate the size of the heroin and/or cocaine drug user (DU population living in the Dakar area (Senegal, and assess the prevalence and risk factors of HIV, hepatitis C virus (HCV and hepatitis B virus (HBV, including behavioural determinants in this population, in order to set up an integrated prevention and treatment programme for DUs. Design and methods: A capture-recapture method was applied for population size estimation, whereas the respondent-driven sampling (RDS method was used to recruit a sample of DUs living in the Dakar area and determine HIV, HBV and HCV prevalence. Behavioural data were gathered during face-to-face interviews, and blood samples were collected on dried blood spots for analysis in a central laboratory. Data analysis was performed using the RDS analysis tool, and risk factors were determined by logistic regression. Access to laboratory results was organized for the participants. Results: The size of the DU population in the Dakar area was estimated to reach 1324 (95% confidence interval (95% CI: 1281–1367. Based on the 506 DUs included in the study, the HIV, HCV and HBV prevalence were 5.2% (95% CI: 3.8–6.3, 23.3% (95% CI: 21.2–25.2 and 7.9% (95% CI: 5.2–11.1, respectively. In people who inject drugs (PWID, prevalence levels increased to 9.4% for HIV and 38.9% for HCV (p=0.001 when compared to those who never injected. Women were more at risk of being HIV infected (prevalence: 13.04% versus 2.97% in males, p=0.001. Being PWID was a risk factor for HCV and HIV infection (odds ratio, OR: 2.7, 95% CI: 1.7–4.3, and OR: 4.3, 95% CI: 1.7–10.7, respectively, whereas older age and female sex were additional risk factors for HIV infection (10% increase per year of age, p=0.03 and OR: 4.9, 95% CI: 1.6–156, respectively. No specific

  12. Kinetics and reaction mechanism of phenol hydroxylation catalyzed by La-Cu4FeAlCO3

    Institute of Scientific and Technical Information of China (English)

    CHEN Chunxia; XU Chenghua; FENG Liangrong; SUO Jishuan; QIU Fali

    2005-01-01

    The present work synthesizes La-Cu4FeAlCO3 catalyst under microwave irradiation and characterizes its structure using XRD and IR techniques. The results show that the obtained La-Cu4FeAlCO3 has a hydrotalcite structure. In the phenol hydroxylation with H2O2 catalyzed by La-Cu4FeAlCO3, the effects of reaction time and phenol/H2O2 molar ratio on the phenol hydroxylation, and relationships between the initial hydroxylation rate with concentration of the catalyst, phenol, H2O2 and reaction temperature are also investigated in details. It is shown the phenol conversion can reach 50.09% (mol percent) in the phenol hydroxylation catalyzed by La-Cu4FeAlCO3, under the reaction conditions of the molar ratio of phenol/H2O2 1/2, the amount ratio of phenol/catalyst 20, reaction temperature 343 K, reaction time 120 min, 10 mL distilled water as solvent. Moreover, a kinetic equation of and the activation energy of Ea=58.37 kJ/mol are obtained according to the kinetic studies. Due to the fact that the HO-Cu+-OH species are detected in La-Cu4FeAlCO3/H2O2 system by XPS, the new mechanism about the generation of hydroxyl free radicals in the phenol hydroxylation is proposed, which is supposed that HO-Cu+-OH species are transition state in this reaction.

  13. The effects of synthesis, Sr-doping, and Co3O 4 on the perovskite LaCoO3

    Science.gov (United States)

    Durand, Alice

    The effects of synthesis method, Sr-doping, and Co3O 4 on the rare-earth perovskite LaCoO3 were examined and quantified. Structural and magnetic measurements were taken using neutron diffraction, X-ray diffraction, transmission electron microscopy, X-ray fluorescence and SQUID magnetometry. An optimal method for synthesizing LaCoO3 nanoparticles is described, and the solid-state synthesis method for nominal LaCoO 3 is found to result in the formation of an extra Co3O 4 phase. Bulk LaCoO3 materials containing systematically varying amounts of the Co3O4 phase (denoted as La wCoO3, where w is the molar ratio La:Co) were also synthesized. As the amount of Co3O4 was increased, the ferromagnetic transition at Tc = 87 K was found to be sharper, the ferromagnetic moment larger, and the ferromagnetism more robust at high fields (H > 100 Oe). This is a similar effect to that from increased tensile strain in LaCoO3 thin films and from increased surface area in nanoparticles. We propose that tensile strain also exists in the LaCoO3-Co3O4 interfaces, which enhances the ferromagnetism. The lattice parameters for LawCoO 3 exhibited thermal expansion behavior that was best fit with a power law, indicating a second-order structural transition at To = 37 K. A mathematical model for the magnetization, M/H, of LawCoO3 was developed which successfully described the behavior at both low and high external fields. The model consists of three contributions to the magnetization: one ferromagnetic contribution and two paramagnetic contributions with different antiferromagnetic exchange interactions. The ferromagnetic contribution is found to have a critical exponent of beta = 0.65, consistent with magnetic ordering of the surface.

  14. STUDI PENGGUNAAN KATALIS ABU SABUT KELAPA, ABU TANDAN SAWIT DAN K2CO3 UNTUK KONVERSI MINYAK JARAK MENJADI BIODIESEL

    Directory of Open Access Journals (Sweden)

    Husni Husin

    2012-05-01

    Full Text Available A STUDY ON THE UTILIZATION OF OIL PALM FIBRE AND FRUIT BUNCH ASH AND K2CO3 FOR CATALYTIC CONVERSION OF JATHROPA OIL TO BIODIESEL. Study on the use of coconut fiber ash, palm bunch ash and K2CO3 as the catalysts for conversion of jatropha oil into biodiesel using methanol solvent has been done. The biodiesel is produced by converting unpurified jatropha oil over catalyst through transesterification reaction. The catalysts are burned at temperature of 500, 600, 800 and 900oC for 10 hours. Transesterification reaction is conducted in three-neck flask at constant temperature of 60oC for 3 hours. The results showed that the unburned and burned coconut fiber ashes at 800oC catalysts give the highest biodiesel yield (87.05 and 87.97% with low soap content (0.23-0.26%. The characteristic of biodiesel produced over those catalysts met the Indonesian and international quality standards, therefore those catalysts can be used as substitute for K2CO3 commercial catalyst.Abstrak   Studi penggunaan katalis abu sabut kelapa, abu tandan sawit dan K2CO3 untuk konversi minyak jarak menjadi biodiesel dengan pelarut metanol telah dilakukan. Biodiesel dibuat melalui konversi minyak jarak yang belum dimurnikan, menggunakan katalis, melalui reaksi transesterifikasi. Katalis-katalis tersebut dipijarkan pada temperatur 500, 600, 800 dan 900oC selama 10 jam. Reaksi dilangsungkan dalam labu leher tiga pada temperatur konstan 60oC selama 3 jam. Hasil penelitian menunjukkan penggunaan katalis abu sabut kelapa tanpa pemijaran dan dengan pemijaran pada 800oC memberikan perolehan biodiesel tertinggi (87,05 dan 87,97% dengan kadar sabun rendah (0,23-0,26%. Karakteristik biodiesel yang dihasilkan dari penggunaan katalis-katalis tersebut ini telah sesuai dengan syarat mutu yang ditetapkan oleh Standar Indonesia dan Internasional, sehingga katalis-katalis tersebut layak digunakan sebagai pengganti katalis K2CO3 komersial

  15. Recovery of Al and Na Values from Red Mud by BaO-Na2CO3 Sinter Process

    Directory of Open Access Journals (Sweden)

    S.N. Meher

    2011-01-01

    Full Text Available The red mud BaO-Na2CO3 sinter process can be used in combination with the Bayer process to recover sodium and aluminium from the red mud waste and direct it back to the process stream. This is facilitated by the high temperature reaction of BaO-Na2CO3 and De-silication product (Sodalite (DSP in the red mud to produce an insoluble di-barium silicate, barium titanate, barium ferrite and a soluble sodium aluminate. A variation of the red mud BaO-Na2CO3 sintering process using half the barium oxide of existing methods has been investigated. The barium to silicon ratio was reduced from 2 to 1 producing a sodium barium silicate (Na2BaSiO4 rather than the di-barium silicate (Ba2SiO4 insoluble phase produced in the existing BaO-Na2CO3 sinter method. Synthetic BaO-Na2CO3 sinter products were investigated to understand the phases produced during sintering at varying temperatures and the chemistry of extraction. The target phases and morphological behaviors of sinter products were seen in XRD and SEM and the highest extractions were produced from a sinter temperature of 1000 °C for 4 h. A two-stage (105 °C / 60 min, 105 °C / 240 min water or caustic leaching process was found to be most effective for extraction. Sodium and aluminium extractions were 99% and 99.5% respectively. The experimental method devised was then used to treat red mud and the target phases were produced. An extraction of sodium and aluminium of 94% and 87% respectively was achieved. Silicon extractions were below 2%. Production benefits include sodium hydroxide savings, liquor burning, increased aluminium extraction and reduced cost of waste handling.

  16. Development of an electrochemically integrated SR-GIXRD flow cell to study FeCO3 formation kinetics

    Science.gov (United States)

    Burkle, D.; De Motte, R.; Taleb, W.; Kleppe, A.; Comyn, T.; Vargas, S. M.; Neville, A.; Barker, R.

    2016-10-01

    An electrochemically integrated Synchrotron Radiation-Grazing Incidence X-Ray Diffraction (SR-GIXRD) flow cell for studying corrosion product formation on carbon steel in carbon dioxide (CO2)-containing brines typical of oil and gas production has been developed. The system is capable of generating flow velocities of up to 2 m/s at temperatures in excess of 80 °C during SR-GIXRD measurements of the steel surface, enabling flow to be maintained over the course of the experiment while diffraction patterns are being collected. The design of the flow cell is presented, along with electrochemical and diffraction pattern transients collected from an initial experiment which examined the precipitation of FeCO3 onto X65 carbon steel in a CO2-saturated 3.5 wt. % NaCl brine at 80 °C and 0.1 m/s. The flow cell is used to follow the nucleation and growth kinetics of FeCO3 using SR-GIXRD linked to the simultaneous electrochemical response of the steel surface which were collected in the form of linear polarisation resistance measurements to decipher in situ corrosion rates. The results show that FeCO3 nucleation could be detected consistently and well before its inhibitive effect on the general corrosion rate of the system. In situ measurements are compared with ex situ scanning electron microscopy (SEM) observations showing the development of an FeCO3 layer on the corroding steel surface over time confirming the in situ interpretations. The results presented demonstrate that under the specific conditions evaluated, FeCO3 was the only crystalline phase to form in the system, with no crystalline precursors being apparent. The numerous capabilities of the flow cell are highlighted and presented in this paper.

  17. PP/石墨/CaCO3导热复合材料制备及性能%Preparation and Property of PP/Graphite/CaCO3 Thermal Conductive Composites

    Institute of Scientific and Technical Information of China (English)

    成敏; 张云灿; 韦亚兵

    2013-01-01

    Polypropylene (PP )/graphite/CaCO3 thermal conductive composites were prepared by melt compounding method. The effects of toughening master batch of Ca-CO3, graphite content on thermal conductivity and mechanical property of the composites were studied respectively. The results show that 500A CaCO3 is the best effective to improve comprehensive property of the composites in all toughening master batch; by adding the toughening master batch and graphite, the toughness and the stiffness of the composites are improved simultaneously; with increasing the content of 500A and graphite, the thermal conductivity and thermal stability of the composites are increased, and the melting temperature is slightly decreased; with increasing of the a-mount of 500A, the crystallinity of PP of the composites decreases, but graphite is the opposite; when the mass ratio of PP/graphite/500A is 45/30/25, the thermal conductivity of the composites is two times more than that of pure PP, the impact strength is similar with pure PP, the notched tensile strength decreases, flexural strength and flexural modulus increase.%采用熔融共混法制备聚丙烯(PP)/石墨/CaCO3导热复合材料,分别研究了CaCO3增韧母料、石墨的添加量对复合材料导热性能及力学性能的影响.结果表明:500A的CaCO3增韧母料对改善复合材料的综合性能最为有效;将石墨和500A共混复合时,可以同时提高复合材料的刚性和韧性;随着500A及石墨用量的增加,复合材料的热导率及热稳定性相应提高,熔融温度略微下降;复合材料中PP的结晶度随500A用量的增加而下降,随石墨用量的增加而增加;PP/石墨/500A(质量比45/30/25)复合材料的热导率为纯PP的3倍,缺口冲击强度与纯PP相近,拉伸强度有所下降,弯曲强度和弯曲模量增加了28%.

  18. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)-cellulose nanowhiskers composites by solution casting

    Science.gov (United States)

    Ten, Elena

    In this research, renewable biobased nanocomposites based on poly(3-hydroxybutyrate- co-3-hydroxyvalerate) and cellulose nanowhiskers were prepared by solution casting. Nanocomposite structure and property investigations were characterized to understand the reinforcing mechanism of CNWs in PHBV and establish longstanding goal of predicting structure--property relationships for material design and optimization. The CNW concentration strongly influenced the extent of nanowhiskers dispersion and level of property enhancement, as determined by structural, mechanical, thermal, dielectric and rheological characterizations. CNW content of 2.3 wt% indicated significant property transitions for all the investigated properties except for rheological ones. The change was believed to be due to the transition from homogeneous CNW dispersion to agglomeration. High CNW content led to CNW agglomerations and reduced nanocomposite moduli, yield strengths and real permittivity. DSC and POM analyses showed that CNWs could alter the nucleation and growth under both non-isothermal and isothermal crystallization conditions. Although the effect of CNW on nucleation ability and degree of crystallinity of PHBV was significant and could contribute to the mechanical properties improvement, the results of this study confirmed that primarily CNW homogeneous distribution and interconnected 3-D structure governed E' enhancement. Oriented PHBV/CNW composites were fabricated in-situ under electric field. CNW were oriented along the direction of applied filed. Image analysis revealed that degree of order and orientation distribution was mainly influenced by CNW content. TEM, DMA and XRD analysis showed that low CNW concentrations resulted in higher degree of anisotropy. Furthermore, for CNW content above 5 wt% the electric field was not sufficient to align CNW given the increased viscosity of PHBV/CNW solutions, hence, restricted mobility of CNW. The superior properties observed in both randomly

  19. Theoretical study on the Co2+OH2/Co3+OH2 electron transfer reactivity

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper presents a contact distance dependence analysis scheme and an ab initio calculation application for the electron transfer (ET) reactivity of Co2+OH2/Co3+OH2 reacting pair. The applicability of these schemes and the corresponding models has been discussed. The contact distance (RCoCo) dependence of the relevant quantities has been analyzed. The results indicate that the activation energy from the accurate PES method agrees well with that from the anharmonic potential method, and they are obviously better than that from the harmonic potential method. The pair distribution function varies from 10-2 to 10-5 along with RCoCo changing from 1.20 to 0.35 nm. The coupling matrix element exponentially decays along with the increase of RCoCo, and the effec-tive electronic coupling requires RCoCo smaller than 0.75 nm. In the range from 0.50 to 0.75 nm for RCoCo, the corresponding electronic transmission coefficient falls within 1.0-10-6. The local ET rate also exponentially decays along with the increase of RCoCo due to the electronic factor. Since the contribution from the pair distribution function to the total ET rate is an inverse measure of that from the electronic factor, the variation of the spherically averaged local ET rate along with RCoCo exhibits a parabola with a maximum at 0.50 nm of RCoCo. This maximum is close to the overall ob-served ET rate value. For this mono-hydrated transition metal ionic system, the ET rate generally is about 106 L·mol-1·s-1 in gaseous process. Further, since it is impossible to experimentally deter-mine the structures and their PESs of these hydrated systems, especially for the unstable interme-diate species, ab initio calculations can play an effective auxiliary role in discussing the ET reactivi-ties of these kinds of reacting systems.

  20. Binder-free Co3O4@NiCoAl-layered double hydroxide core-shell hybrid architectural nanowire arrays with enhanced electrochemical performance

    Science.gov (United States)

    Li, Xuan; Yang, Zhengchun; Qi, Wen; Li, Yutao; Wu, Ying; Zhou, Shaoxiong; Huang, Shengming; Wei, Jun; Li, Huijun; Yao, Pei

    2016-02-01

    Herein, binder-free Co3O4@NiCoAl-layered double hydroxide (Co3O4@LDH) core-shell hybrid architectural nanowire arrays were prepared via a two-step hydrothermal synthesis route. LDH nanosheets possessing a large electroactive surface area uniformly dispersed on the surface of Co3O4 nanowires were successfully fabricated allowing for fast electron transport that enhances the electrochemical performance of LDH nanosheets. Co3O4@LDH nanowire arrays of 2 to 1.5 molar ratio (Co3O4:LDH) exhibit high specific capacitance (1104 F g-1 at 1 A g-1), adequate rate capability and cycling stability (87.3% after 5000 cycles), attributed to the synergistic effect between the robust Co3O4 nanowire arrays and LDH nanosheets.

  1. CeO2-Co3O4纳米晶粒对甲烷气敏性影响分析%Methane Gas-sensitive Property Analysis Influenced by CeO2-Co3O4 Nanocrystalline

    Institute of Scientific and Technical Information of China (English)

    曹小荣; 胡明江

    2016-01-01

    为了快速准确检测矿井中的甲烷气体浓度,以直接沉淀法制备了不同含量CeO2的CeO2-Co3 O4纳米晶粒。利用掩膜法将制备的CeO2-Co3 O4纳米晶粒镀膜于氧化硅绝缘层表面形成敏感薄膜,采用标准MEMS工艺制作了一种薄膜型甲烷传感器。采用 X 射线衍射仪表征了CeO2-Co3 O4纳米晶粒的相组成和微观形貌,利用全自动程序化学吸附仪分析了CeO2-Co3 O4纳米晶粒对甲烷的吸附机理。在气体传感器静态测试系统上,测试了甲烷传感器灵敏度、湿度、温度、动态响应、抗干扰和长期稳定性等特性。结果表明:以Ce30为敏感薄膜的甲烷传感器灵敏度为98.3%,动态响应时间为11 s,恢复时间为8 s。在矿井中连续使用12个月后,灵敏度衰减了8.5%。表明该甲烷传感器可实现矿井中甲烷气体在线检测。%In order to detect methane concentration in mine quickly and accurately,CeO2-Co3O4 nanocrystalline were pre-pared by direct precipitation method.CeO2-Co3O4 nanocrystalline was deposited onto the insulating layer of silicon oxide surface by mask method.A new film-type methane gas sensor was designed by micro electro mechanical system.The crystalline phase and microstructure of CeO2-Co3 O4 nanocrystalline were displayed using X-ray diffraction ( XRD) and field emission scanning electron microscope ( FE-SEM ) , methane adsorption mechanism of CeO2-Co3 O4 nanocrystalline were analyzed by automatic program chemisorption analyzer.These characteristic tests of methane gas sensors were carried out on the traits of sensitive performance, temperature,relative humidity,dynamic response,interference and long-term stability in gas sensor static test system.The conclu-sion demonstrates that the sensitivity of methane gas sensor based on Ce30 sensitive thin film was 98.3%,the dynamic response time and recover time of methane gas sensor were 11 s and 8 s respectively.The sensitivity of methane gas sensor was attenuated about 8

  2. 原位悬浮聚合PVC/纳米CaCO3的制备及其性能%Properties of PVC/nano-CaCO3 composite resin prepared by in-situ suspension polymerization

    Institute of Scientific and Technical Information of China (English)

    王士财

    2005-01-01

    利用原位悬浮聚合法制备了聚氯乙烯(PVC)/纳米CaCO3复合树脂,并对其性能进行了研究.结果表明,与PVC相比,PVC/纳米CaCO3复合树脂的热稳定性、增塑剂吸收量及表观密度等有所提高;冲击强度由4.9 kJ/m2增加到13.0 kJ/m2;拉伸强度由58.2 MPa增加到59.5 MPa;断裂伸长率由57.8%增加到75.6%,达到了增韧增强的效果.

  3. Sequestering uranium from UO2(CO3)3(4-) in seawater with amine ligands: density functional theory calculations.

    Science.gov (United States)

    Guo, Xiaojing; Huang, Liangliang; Li, Cheng; Hu, Jiangtao; Wu, Guozhong; Huai, Ping

    2015-06-14

    The polystyrene-supported primary amine -CH2NH2 has shown an at least 3-fold increase in uranyl capacity compared to a diamidoxime ligand on a polystyrene support. This study aims to understand the coordination of substitution complexes from UO2(CO3)3(4-) and amines using density functional theory calculations. Four kinds of amines (diethylamine (DEA), ethylenediamine (EDA), diethylenetriamine (DETA) and triethylenetetramine (TETA)) were selected because they belong to different classes and have different chain lengths. The geometrical structures, electronic structures and the thermodynamic stabilities of various substitution complexes, as well as the trends in their calculated properties were investigated at equilibrium. In these optimized complexes, DEA groups bind to uranyl as monodentate ligands; EDA groups serve as monodentate and bidentate ligands; DETA groups act as monodentate and tridentate ligands; while TETA groups serve as monodentate, bidentate and tridentate ligands. The thermodynamic analysis confirmed that the primary amines coordinate to uranyl more strongly than does the secondary amine. The stabilities of substitution complexes with primary amines were calculated to decrease with increasing chain length of the amine, except for UO2(L2)(2+). Of the complexes analyzed, only UO2L(CO3)2(2-) (L = EDA and DETA) and UO2L2CO3 (L = EDA) were predicted to form from the substitution reactions with UO2(CO3)3(4-) and protonated amines as reactants in aqueous solution. Amines were calculated to be comparable to, or sometimes weaker than, amidoximate in replacing CO3(2-) in UO2(CO3)3(4-) to coordinate to uranium. Therefore, the coordination mechanism, in which amines replace carbonates to bind to uranyl, is not primarily responsible for the experimentally observed 3-fold or greater increase in uranyl capacity of primary amines compared to a diamidoxime ligand. Based on the results of our calculations, we believe that the cation exchange mechanism, in which the

  4. Effects of Ce3+, Nd3+, Gd3+, Tb3+ and Lu3+ions on Formation of CaCO3

    Institute of Scientific and Technical Information of China (English)

    黄健; 许善锦; 卢景芬; 王夔

    2003-01-01

    The effects of lanthanides at various concentrations on CaCO3 crystal growth were studied by X-ray diffraction (XRD), infrared spectra (IR), X-ray photoelectric energy spectra (XPS) and inductively coupled plasma mass spectrometry (ICP-MS). It was found that the calcite, a stable form of CaCO3 in thermodynamics, is the predominant species. The research indicates that lanthanide ions (Ln3+) can partly substitute the Ca2+ in the lattice of CaCO3 crystals, and change the crystal characterization and direct the ordinal growth of CaCO3 crystals.

  5. Doping nano-Co3O4 surface with bigger nanosized Ag and its photocatalytic properties for visible light photodegradation of organic dyes

    Science.gov (United States)

    Chen, Guangliang; Si, Xiaolei; Yu, Jinsong; Bai, Huiyu; Zhang, Xianhui

    2015-03-01

    This paper reports the synthesis of nanosized Ag/Co3O4 composite catalysts using a silver-mirror reaction and the calibration of their catalytic activities towards methyl blue (MB) dye degradation with peroxymonosulfate (PMS) under visible light. The nanosized Ag/Co3O4 composites were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-vis spectroscopy. The experimental evidence indicated that the hydrothermal synthesis approach lead to the exposure of the {1 1 2} facets of the Co3O4 nanoflakes. Compared to Co3O4 nanoflakes, Co3O4 doped with Ag nanoparticle (average diameters of 10-15 nm) presented lower band gap energy and photoluminescent (PL) intensity. Meanwhile, the Ag/Co3O4 exhibited high stability and excellent dispersion property in dye solution. Experimental data suggested that 3.06 wt% Ag nanoparticle-doped Ag/Co3O4 nanocomposite catalyst possessed the highest catalytic activity towards MB degradation in aqueous solution at the tested concentration level of 15 mg/L, about 2.4 times higher than that of pure Co3O4. Complete decolorization of the 15 mg/L MB solution can be achieved by 3.06 wt% Ag-doped Ag/Co3O4 nanocomposite within 20 min of visible light irradiation.

  6. The luminescence properties of the heteroleptic [Re(CO)3(N∩N)Cl] and [Re(CO)3(N∩N)(CH3CN)](+) complexes in view of the combined Marcus-Jortner and Mulliken-Hush formalism.

    Science.gov (United States)

    Woźna, Agnieszka; Kapturkiewicz, Andrzej

    2015-11-11

    The luminescence properties of the heteroleptic fac-Re(CO)3(+) complexes with α-diimine N∩N ligands, neutral [Re(CO)3(N∩N)Cl] and cationic [Re(CO)3(N∩N)(CH3CN)](+) species, have been studied in acetonitrile solutions at room temperature. The investigated complexes exhibit the metal to ligand charge-transfer (MLCT) phosphorescence with the emission characteristics strongly affected by the nature of coordinated α-diimine N∩N ligands. The observed trends can be quantitatively described by invoking the electronic interactions between (3)*LC and (3)*MLCT states as well as the spin-orbit interactions between (3)*MLCT and (1)*MLCT states, respectively. All quantities necessary for the description can be straightforwardly accounted from analysis of the radiative (1)*MLCT ← S0 and (3)*MLCT → S0 charge transfer processes. It is also demonstrated that the radiative kr and non-radiative knr decay rate constants of the excited (3)*MLCT states can be interpreted within the same set of parameters. As expected from the Mulliken-Hush formalism the both processes are strictly related that allows prediction of the non-radiative knr rate constants using the parameters available from analysis of the radiative (1)*MLCT ← S0 and (3)*MLCT → S0 charge transfer processes.

  7. Electromagnetic Frequency Influence on CaCO3 Fouling Crystallization%电磁场频率对CaCO3型污垢结晶的影响

    Institute of Scientific and Technical Information of China (English)

    王建国; 刘高生; 孙伟

    2013-01-01

    Based on the self-made electromagnetic water treatment device with variable frequency, the influence of electromagnetic fields with different frequencies on CaCO3 fouling crystallization process was analyzed. Considering the relational characteristics of the solution conductivity and the plus magnetic, the multi-extreme value relation curves between the different frequency slope and frequency were simulated with the least squares method; the multi-extreme value relation curves between the calcium ion concentration-alkalinity and frequency to be obtained through the static titration can provide experimental basis for the CaCO3 fouling' s formation and the perfection of electromagnetic scale suppression method.%基于自制的变频电磁水处理装置,研究不同频率的电磁场对碳酸钙结晶过程的影响.针对溶液电导率与加磁时间的关系特性,采用最小二乘法拟合出不同频率下其斜率与频率之间的多极值关系曲线;采用静态滴定法获得了钙离子浓度和碱度与频率之间的多极值关系曲线.为CaCO3污垢形成机理与电磁抑垢方法的完善提供了实验依据.

  8. Preparation and electrochemical properties of NiO-Co3O4 composite as electrode materials for supercapacitors

    Science.gov (United States)

    Wang, X. W.; Zheng, D. L.; Yang, P. Z.; Wang, X. E.; Zhu, Q. Q.; Ma, P. F.; Sun, L. Y.

    2017-01-01

    The precursor of NiO-Co3O4 composites was synthesized via a simple hydrothermal process. After that, the precursor was calcined at 300 °C for 3 h to obtain the composite powders. The powders calcined at 300 °C showed amorphous, and the powders calcined at 400 °C and 500 °C for comparison showed the composite phase of NiO and Co3O4. The composite products showed a microstructure of micro-spheres. For the samples calcined at 300 °C for 3 h, the specific capacitance reached 801 F g-1 at a current density of 1 A g-1.

  9. Enhanced magnetocaloric effect in a Co-doped Heusler Mn50Ni37Co3In10 unidirectional crystal

    Science.gov (United States)

    Ren, Jian; Feng, Shutong; Fang, Yue; Zhai, Qijie; Luo, Zhiping; Zheng, Hongxing

    2016-11-01

    A high-pressure optical zone-melting technique was employed to grow a Mn-rich Heusler Mn50Ni37Co3In10 unidirectional crystal in the present study. It was found that the Co-doped Mn50Ni37Co3In10 unidirectional crystal showed a low magnetic hysteretic loss and a widened working temperature interval in the vicinity of the martensitic transformation. The inverse magnetic entropy change (∆SM) reached 7.84 Jkg-1K-1 around 237.5 K under a magnetic field change of 30 kOe, and the corresponding effective refrigeration capacity (RCeff) was about 127.2 Jkg-1. The experimental results demonstrated a high potential to develop high-performance Mn-rich Heusler Mn-Ni-In magnetocaloric materials by means of Co doping in combination with the high-pressure optical zone-melting fabrication technique.

  10. Topological characterization of nanocrystalline cellulose reinforced Poly (lactic acid) and Poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) bionanocomposites

    Science.gov (United States)

    Bhat, A. H.; Dasan, Y. K.; Khan, Ihsan Ullah; Ahmad, Faiz; Ayoub, Muhammad

    2016-11-01

    This study was conducted to evaluate the morphological and barrier properties of nanocrystalline cellulose reinforced Poly (lactic acid) and Poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) bionanocomposites. Nanocrystalline cellulose was isolated from waste oil palm empty fruit bunch fiber using Sulphuric acid hydrolysis. Chemical modifications of nanocrystalline cellulose was performed to allow good compatibilization between fiber and the polymer matrices and also to improve dispersion of fillers. Bionanocomposite materials were produced from these nanocrystalline cellulose reinforced Poly (lactic acid) and Poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) using solvent casting and evaporation techniques. The properties of extracted nanocrystalline cellulose were examined using FT-IR spectroscopy, X-ray diffractometer, TEM and AFM. Besides that, the properties of bionanocomposites were examined through FESEM and oxygen permeability properties analysis. Better barrier and morphological properties were obtained for nanocrystalline cellulose reinforced bionanocomposites than for neat polymer blend.

  11. The synthesis and pH-dependent behaviour of Re(CO)3 conjugates with diimine phenolic ligands.

    Science.gov (United States)

    Chanawanno, Kullapa; Engle, James T; Le, Kevin X; Herrick, Richard S; Ziegler, Christopher J

    2013-10-07

    In this report we present a study of a series of Re(CO)3 pyridine-imine complexes with pendant phenol groups. We investigated the effects of the position of the phenol hydroxyl group (para, meta or ortho to the imine) on the steric and electronic characteristics of a series of Re(CO)3X(pyca-C6H4OH) compounds, where X = Cl, Br and pyca = pyridine-2-carbaldehyde imine. These compounds can be generated either via ligand synthesis followed by metal chelation (compound 4) or via a one-pot method (compounds 2, 3, 5 and 6). All six compounds show striking differences in pH-dependent UV-visible absorption based on the position of the phenol hydroxyl group.

  12. Improving water tolerance of Co3O4 by SnO2 addition for CO oxidation

    Science.gov (United States)

    Xu, Xianglan; Sun, Xiongfei; Han, Hong; Peng, Honggen; Liu, Wenming; Peng, Xing; Wang, Xiang; Yang, Xiangjie

    2015-11-01

    A series of Sn-modified Co3O4 catalysts with different Co/Sn molar ratios were prepared via co-precipitation method and characterized by N2-BET, XRD, H2-TPR, XPS and FTIR techniques. The addition of a small amount of Sn into Co3O4 has a mild influence on its CO oxidation activity, but promotes its water resistance evidently. The major reason is attributed to the effective suppressing of water adsorption on the catalyst surface by Sn addition, as testified by FTIR results. Co0.90Sn0.10, a catalyst with a Co/Sn molar ratio of 0.90/0.10, shows the potential to be used in some real emission control processes for CO oxidation due to its reasonable activity and evidently improved reaction stability in the presence of water vapour.

  13. Preparation and Characterization of Anadara Granosa Shells and CaCO3 as Heterogeneous Catalyst for Biodiesel Production

    Directory of Open Access Journals (Sweden)

    Hadiyanto Hadiyanto

    2016-03-01

    Full Text Available Nowadays, the use of homogenous catalyst has been gradually reduced for its operational reason. The homogenous catalyst leads in difficulty of separation after the process completed and the life cycle is shorter. Therefore, most of researches are introducing heterogenous catalyst for its substitution. This research was aimed to evaluate the use of shell of Anadara granosa and CaCO3 as source of CaO based catalyst through impregnation method. The preparation of the catalyst was started by decomposition of shells and CaCO3 at temperature of 800 oC for 3 hours, followed by impregnation at 70 oC for 4 hours and then calcined at 800 oC for 2 hours. The CaCO3 based catalyst gained high yield of biodiesel (94% as compared to Anadara granoasa based catalyst (92%. The reusability study showed that these catalysts could be used until three times recycle with 40-60% yield of biodiesel. The CaO contents of catalyst decreased up to 90% after three times recycles. Copyright © 2016 BCREC GROUP. All rights reserved Received: 10th November 2015; Revised: 6th January 2016; Accepted: 6th January 2016 How to Cite: Hadiyanto, H., Lestari, S.P., Widayat, W. (2016. Preparation and Characterization of Anadara Granosa Shells and CaCO3 as Heterogeneous Catalyst for Biodiesel Production. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (1: 21-26. (doi:10.9767/bcrec.11.1.402.21-26 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.1.402.21-26

  14. Investigation of gas concentration cell based on LiSiPO electrolyte and Li2CO3, Au electrode

    Institute of Scientific and Technical Information of China (English)

    ZHU YongMing; CHU WingFong; WEPPNER Werner

    2009-01-01

    Solid lithium ion conducting electrochemical cells using LiSiPO as solid electrolyte and Li2CO3 mixed with Au as electrodes were prepared and employed as chemical sensors for the detection of CO2 gas.The EMF of the cell depends on the concentration of CO2 in air according to the partial pressure de-pendence of Nernst's law in the investigated range from 100 to 2000 ppm over the temperature range from 473 K to 673 K.

  15. Controlling the Vaterite CaCO3 Crystal Pores. Design of Tailor-Made Polymer Based Microcapsules by Hard Templating.

    Science.gov (United States)

    Feoktistova, Natalia; Rose, Juergen; Prokopović, Vladimir Z; Vikulina, Anna S; Skirtach, Andre; Volodkin, Dmitry

    2016-05-03

    The spherical vaterite CaCO3 microcrystals are nowadays widely used as sacrificial templates for fabrication of various microcarriers made of biopolymers (e.g., proteins, nucleic acids, enzymes) due to porous structure and mild template elimination conditions. Here, we demonstrated for the first time that polymer microcarriers with tuned internal nanoarchitecture can be designed by employing the CaCO3 crystals of controlled porosity. The layer-by-layer deposition has been utilized to assemble shell-like (hollow) and matrix-like (filled) polymer capsules due to restricted and free polymer diffusion through the crystal pores, respectively. The crystal pore size in the range of few tens of nanometers can be adjusted without any additives by variation of the crystal preparation temperature in the range 7-45 °C. The temperature-mediated growth mechanism is explained by the Ostwald ripening of nanocrystallites forming the crystal secondary structure. Various techniques including SEM, AFM, CLSM, Raman microscopy, nitrogen adsorption-desorption, and XRD have been employed for crystal and microcapsule analysis. A three-dimensional model is introduced to describe the crystal internal structure and predict the pore cutoff and available surface for the pore diffusing molecules. Inherent biocompatibility of CaCO3 and a possibility to scale the porosity in the size range of typical biomacromolecules make the CaCO3 crystals extremely attractive tools for template assisted designing tailor-made biopolymer-based architectures in 2D to 3D targeted at drug delivery and other bioapplications.

  16. Polar coralline algal CaCO3-production rates correspond to intensity and duration of the solar radiation

    Directory of Open Access Journals (Sweden)

    S. Teichert

    2013-08-01

    Full Text Available In this study we present a comparative quantification of CaCO3 production rates by rhodolith-forming coralline red algal communities situated in high polar latitudes and assess which environmental parameters control these productions rates. The present rhodoliths act as ecosystem engineers and their carbonate skeletons provide an important ecological niche to a variety of benthic organisms. The settings are distributed along the coasts of the Svalbard archipelago, being Floskjeret (78°18' N in Isfjorden, Krossfjorden (79°08' N at the eastern coast of Haakon VII Land, Mosselbukta (79°53' N at the eastern coast of Mosselhalvøya, and Nordkappbukta (80°31' N at the northern coast of Nordaustlandet. All sites feature Arctic climate and strong seasonality. The algal CaCO3 production rates were calculated from fuchsine stained annual growth increments exhibited by the rhodoliths and range from 100.9 g (CaCO3 m−2 yr−1 at Nordkappbukta to 200.3 g (CaCO3 m−2 yr−1 at Floskjeret. The rates correlate to various environmental parameters with geographical latitude being the most significant (negative correlation, R2 = 0.95, p R2 = 0.93, p R2 = 0.87, p = 0.07, and the annual mean temperature (positive correlation, R2 = 0.48, p < 0.05. This points out sufficient light incidence to be the main control of the growth of the examined coralline red algal rhodolith communities, while temperature is less important. Thus, the ongoing global change with its rising temperatures will most likely result in impaired conditions for the algal, because the concomitant increased global runoff will decrease water transparency and hence light incidence at the four offshore sites. Regarding the aforementioned role of the rhodoliths as ecosystem engineers, the impact on the associated organisms will presumably also be negative.

  17. Two different hydrogen bond donor ligands together: a selectivity improvement in organometallic {Re(CO)3} anion hosts.

    Science.gov (United States)

    Ion, Laura; Nieto, Sonia; Pérez, Julio; Riera, Lucía; Riera, Víctor; Díaz, Jesús; López, Ramón; Anderson, Kirsty M; Steed, Jonathan W

    2011-09-05

    Rhenium(I) compounds [Re(CO)(3)(Hdmpz)(2)(ampy)]BAr'(4) and [Re(CO)(3)(N-MeIm)(2)(ampy)]BAr'(4) (Hdmpz = 3,5-dimethylpyrazole, N-MeIm = N-methylimidazole, ampy = 2-aminopyridine or 3-aminopyridine) have been prepared stepwise as the sole reaction products in good yields. The cationic complexes feature two different types of hydrogen bond donor ligands, and their anion binding behavior has been studied both in solution and in the solid state. Compounds with 2-ampy ligands are labile in the presence of nearly all of the anions tested. The X-ray structure of the complex [Re(CO)(3)(Hdmpz)(2)(ampy)](+) (2) shows that the 2-ampy ligand is metal-coordinated through the amino group, a fact that can be responsible for its labile character. The 3-ampy derivatives (coordinated through the pyridinic nitrogen atom) are stable toward the addition of several anions and are more selective anion hosts than their tris(pyrazole) or tris(imidazole) counterparts. This selectivity is higher for compound [Re(CO)(3)(N-MeIm)(2)(MeNA)]BAr'(4) (5·BAr'(4), MeNA = N-methylnicotinamide) that features an amido moiety, which is a better hydrogen bond donor than the amino group. Some of the receptor-anion adducts have been characterized in the solid state by X-ray diffraction, showing that both types of hydrogen bond donor ligands of the cationic receptor participate in the interaction with the anion hosts. DFT calculations suggest that coordination of the ampy ligands is more favorable through the amino group only for the cationic complex 2, as a consequence of the existence of a strong intramolecular hydrogen bond. In all other cases, the pyridinic coordination is clearly favored.

  18. Influences of the [Co2+]/[Co3+] Ratio on the Process of Liquid-phase Oxidation of Toluene by Air%甲苯液相空气氧化过程中[Co2+]/[Co3+]的测定及其对反应的影响

    Institute of Scientific and Technical Information of China (English)

    唐盛伟; 沈伟; 梁斌

    2009-01-01

    Liquid phase oxidation of toluene is an environmental benign route for the production of benzoic acid. In aφ48 mm bubble column reactor, the commercial process of toluene liquid phase oxidation was conducted with Co(CH3COO)2.4H2o as catalyst. The Co2+ concentration [Co2+] was determined by extraction spectrophotometry and hereby the Co3+ concentration [Co3+] was obtained by mass balance. The results showed that [Co3+] reached the maximum at about 25-30 min. [Co3+] increased with increasing Co catalyst amount at total Co concentration <150 mg'L-1 of toluene. The conversion of toluene, yield and selectivity of benzoic acid increased with the increasing [Co3+/Co2+]max. A high [Co3+] and a high [Co3+]/[Co2+] ratio are beneficial to the reaction.

  19. Gyroscope-Like Complexes Based on Dibridgehead Diphosphine Cages That Are Accessed by Three-Fold Intramolecular Ring Closing Metatheses and Encase Fe(CO)3, Fe(CO)2(NO)(+), and Fe(CO)3(H)(+) Rotators.

    Science.gov (United States)

    Lang, Georgette M; Shima, Takanori; Wang, Leyong; Cluff, Kyle J; Skopek, Katrin; Hampel, Frank; Blümel, Janet; Gladysz, John A

    2016-06-22

    Reactions of trans-Fe(CO)3(P((CH2)mCH═CH2)3)2 (m = a/4; b/5, c/6, e/8) and Grubbs' catalyst (12-24 mol %, CH2Cl2, reflux) give the cage-like trienes trans- Fe(CO)3(P((CH2)mCH═CH(CH2)m)3 P) (3a-c,e, 60-81%). Hydrogenations (ClRh(PPh3)3, 60-80 °C) yield the title compounds trans- Fe(CO)3(P((CH2)n)3 P) (4a-c,e, 74-86%; n = 2m + 2), which have idealized D3h symmetry. A crystal structure of 4c suggests enough van der Waals clearance for the Fe(CO)3 moiety to rotate within the three P(CH2)14P linkages; structures of E,E,E-3a show rotation to be blocked by the shorter P(CH2)4CH═CH(CH2)4P linkages. Additions of NO(+)BF4(-) give the isoelectronic and isosteric cations [ Fe(CO)2(NO)(P((CH2)n)3 P)](+)BF4(-) (5a-c(+)BF4(-); 81-98%). Additions of [H(OEt2)2](+)BArf(-) (BArf = B(3,5-C6H3(CF3)2)4) afford the metal hydride complexes mer,trans-[ Fe(CO)3(H)(P((CH2)n)3 P)](+)BArf(-) (6a-c,e(+)BArf(-); 98-99%). The behavior of the rotators in the preceding complexes is probed by VT NMR. At ambient temperature in solution, 5a,b(+)BF4(-) and 6a(+)BArf(-) show two sets of P(CH2)n/2 (13)C NMR signals (2:1), whereas 5c(+)BF4(-) and 6b,c(+)BArf(-) show only one. At higher temperatures, the signals of 5b(+)BF4(-) coalesce; at lower temperatures, those of 5c(+)BF4(-) and 6b(+)BArf(-) decoalesce. These data give ΔH(⧧)/ΔS(⧧) values (kcal/mol and eu) of 8.3/-28.4 and 9.5/-6.5 for Fe(CO)2(NO)(+) rotation (5b,c(+)) and 6.1/-23.5 for Fe(CO)3(H)(+) rotation (6b(+)). (13)C CP/MAS NMR spectra show that the Fe(CO)3 moiety in polycrystalline 4c (but not 4a) undergoes rapid rotation between -60 and 95 °C. Approaches to minimizing these barriers and developing molecular gyroscopes are discussed.

  20. Thermal formation of mesoporous single-crystal Co3O4 nano-needles and their lithium storage properties

    KAUST Repository

    Lou, Xiong Wen

    2008-01-01

    In this work, we report the simple solid-state formation of mesoporous Co3O4 nano-needles with a 3D single-crystalline framework. The synthesis is based on controlled thermal oxidative decomposition and re-crystallization of precursor β-Co(OH)2 nano-needles. Importantly, after thermal treatment, the needle-like morphology can be completely preserved, despite the fact that there is a large volume contraction accompanying the process: β-Co(OH)2 → Co3O 4. Because of the intrinsic crystal contraction, a highly mesoporous structure with high specific surface area has been simultaneously created. The textual properties can be easily tailored by varying the annealing temperature between 200-400 °C. Interestingly, thermal re-crystallization at higher temperatures leads to the formation of a perfect 3D single-crystalline framework. Thus derived mesoporous Co3O4 nano-needles serve as a good model system for the study of lithium storage properties. The optimized sample manifests very low initial irreversible loss (21%), ultrahigh capacity, and excellent cycling performance. For example, a reversible capacity of 1079 mA h g-1 can be maintained after 50 cycles. The superior electrochemical performance and ease of synthesis may suggest their practical use in lithium-ion batteries. © The Royal Society of Chemistry 2008.

  1. Study on application of CeO2 and CaCO3 nanoparticles in lubricating oils

    Institute of Scientific and Technical Information of China (English)

    GU Caixiang; LI Qingzhu; GU Zhuoming; ZHU Guangyao

    2008-01-01

    The ceria (CeO2) nanoparticles and calcium carbonate (CaCO3) nanoparticles were chosen as additives of anti-wear and extreme pressure for lubricating oils, and the morphology and sizes of nanoparticles were examined using Transmission Electron Microscope (TEM). The tribological performance of lubricating oils containing combined nanoparticles were determined by four-ball friction and wear tester, and the chemical composition of steel ball with worn surface were analyzed by X-ray Photoelectron Spectrum(XPS). The results showed that the lubricating oils containing combined nanoparticles had good anti-wear and friction reducing effects, and the tribological properties were optimal when WCeO2+CaCO3=0.6%, WCeO2:WCaCO3=1:1. The extreme pressure value increased by 40.25%, the wear spot diameter reduced by 33.5%, and friction coefficient reduced by 32% compared with 40CD oil. The coordinated action of big and small particles made anti-wear and friction reducing effective. Tribological chemical reactions resulting from the friction surface formed metal calcium, metal cerium and oxides film, and they could fill up the concave surface and protect the worn surface.

  2. Tropical Cyclones Cause CaCO3 Undersaturation of Coral Reef Seawater in a High-CO2 World

    Science.gov (United States)

    Manzello, D.; Enochs, I.; Carlton, R.; Musielewicz, S.; Gledhill, D. K.

    2013-12-01

    Ocean acidification is the global decline in seawater pH and calcium carbonate (CaCO3) saturation state (Ω) due to the uptake of anthropogenic CO2 by the world's oceans. Acidification impairs CaCO3 shell and skeleton construction by marine organisms. Coral reefs are particularly vulnerable, as they are constructed by the CaCO3 skeletons of corals and other calcifiers. We understand relatively little about how coral reefs will respond to ocean acidification in combination with other disturbances, such as tropical cyclones. Seawater carbonate chemistry data collected from two reefs in the Florida Keys before, during, and after Tropical Storm Isaac provide the most thorough data to-date on how tropical cyclones affect the seawater CO2-system of coral reefs. Tropical Storm Isaac caused both an immediate and prolonged decline in seawater pH. Aragonite saturation state was depressed by 1.0 for a full week after the storm impact. Based on current 'business-as-usual' CO2 emissions scenarios, we show that tropical cyclones with high rainfall and runoff can cause periods of undersaturation (Ω strength, frequency, and rainfall of the most severe tropical cyclones with climate change in combination with ocean acidification will negatively impact the structural persistence of coral reefs over this century.

  3. A novel Bacillus sp. accumulating poly (3-hydroxybutyrate-co-3-hydroxyvalerate) from a single carbon substrate.

    Science.gov (United States)

    Reddy, S Vishnuvardhan; Thirumala, M; Mahmood, S K

    2009-06-01

    The objective of this paper was to report a bacterium designated as 88D, capable of producing poly (3-hydroxybutyrate-co-3-hydroxyvalerate) [P (3HB-co-3HV)] copolymer from a single carbon source, which was isolated from a municipal sewage treatment plant in Hyderabad, India. This microorganism, based on the phenotypical features and genotypic investigations, was identified as Bacillus sp. The optimal growth of Bacillus sp. 88D occurred between 28 and 30 degrees C and at pH 7. The strain yielded a maximum of 64.62% dry cell weight (DCW) polymer in the medium containing glucose as carbon source, which was followed by 60.46% DCW polymer in glycerol containing medium. Bacillus sp. 88D produced P (3HB-co-3HV) from glucose or glycerol, when they were used as a single carbon substrate. This bacterium produced polyhydrxybutyrate (PHB) when sodium acetate was used as sole carbon substrate. The viscosity average molecular mass (Mv) of the copolymers ranged from 523 to 627 kDa. The physical, chemical and mechanical properties of the biopolymers were characterized.

  4. Origin of Capacity Fading in Nano-Sized Co3O4Electrodes: Electrochemical Impedance Spectroscopy Study

    Directory of Open Access Journals (Sweden)

    Kang Jin-Gu

    2008-01-01

    Full Text Available Abstract Transition metal oxides have been suggested as innovative, high-energy electrode materials for lithium-ion batteries because their electrochemical conversion reactions can transfer two to six electrons. However, nano-sized transition metal oxides, especially Co3O4, exhibit drastic capacity decay during discharge/charge cycling, which hinders their practical use in lithium-ion batteries. Herein, we prepared nano-sized Co3O4with high crystallinity using a simple citrate-gel method and used electrochemical impedance spectroscopy method to examine the origin for the drastic capacity fading observed in the nano-sized Co3O4anode system. During cycling, AC impedance responses were collected at the first discharged state and at every subsequent tenth discharged state until the 100th cycle. By examining the separable relaxation time of each electrochemical reaction and the goodness-of-fit results, a direct relation between the charge transfer process and cycling performance was clearly observed.

  5. Sensing Properties of Pd-Loaded Co3O4 Film for a ppb-Level NO Gas Sensor

    Directory of Open Access Journals (Sweden)

    Takafumi Akamatsu

    2015-04-01

    Full Text Available We prepared 0.1 wt%–30 wt% Pd-loaded Co3O4 by a colloidal mixing method and investigated the sensing properties of a Pd-loaded Co3O4 sensor element, such as the sensor response, 90% response time, 90% recovery time, and signal-to-noise (S/N ratio, toward low nitric oxide (NO gas levels in the range from 50 to 200 parts per billion. The structural properties of the Pd-loaded Co3O4 powder were investigated using X-ray diffraction analysis and transmission electron microscopy. Pd in the powder existed as PdO. The sensor elements with 0.1 wt%–10 wt% Pd content have higher sensor properties than those without any Pd content. The response of the sensor element with a 30 wt% Pd content decreased markedly because of the aggregation and poor dispersibility of the PdO particles. High sensor response and S/N ratio toward the NO gas were achieved when a sensor element with 10 wt% Pd content was used.

  6. Influence of Na2 CO3 as Additive on Direct Reduction of Boron-bearing Magnetite Concentrate

    Institute of Scientific and Technical Information of China (English)

    Yong-li LI; Jing-kui QU; Guang-ye WEI; Tao QI

    2016-01-01

    Boron-bearing magnetite concentrate is typically characterized by low grade of iron and boron (wTFe=51%-54%,wB2 O3=6%-8%),as well as the close intergrowth of ascharite phase and magnetite phase.A promising technology was proposed to separate iron and boron by coupling the direct reduction of iron oxides and Na activation of boron minerals together.The influence of Na2 CO3 as additive on the direct reduction of boron-bearing magnetite was studied by chemical analysis,kinetic analysis,XRD analysis and SEM analysis.The results showed that the ad-dition of Na2 CO3 not only activated boron minerals,but also reduced the activation energy of the reaction and pro-moted the reduction of iron oxides.Besides,the addition of Na2 CO3 changed the composition and melting point of non-ferrous phase,and then promoted the growth and aggregation of iron grains,which was conducive to the subse-quent magnetic separation.Thus,the coupling of the two processes is advantageous.

  7. Biomimetic Nucleation and Morphology Control of CaCO_3 in PAAm Hydrogels Synthesized from Lyotropic Liquid Crystalline Templates

    Institute of Scientific and Technical Information of China (English)

    DU, Zhuwei; LU, Cuixiang; LI, Haoran; LI, Dingjie

    2009-01-01

    Hydrogels have been thought to be the material which can provide appealing replacements of biological organisms. Pores of hydrogeis synthesized from lyotropic liquid crystalline (LLC) templates were smaller in size and more uniform than those of traditional hydrogels. LLC poly-acrylamide (PAAm) hydrogels were used as the growth media of CaCO_3. After copolymerized with acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid (AMPS),LLC hydrogels were modified with COOH and SO_3H, respectively. The effect of functional groups on the biomitactic mineralization of CaCO_3 was studied. Most of crystals from traditional hydrogels are rhombohedral and could not form aggregates. Only a few could aggregate and have a particular morphology with irregular orientation of subcrystal. Compared with crystals separated from traditional hydrogels, crystals growing in the LLC hydrogels were much more regulated and could form aggregates with particular morphology and regular orientation, that is,face (104) of rhombohedral subcrystals parallel to the surface of the macrocrystals. Modification of COOH and SO_3H groups made CaCO_3 subcrystal align more tightly. COOH had minor influences on the crystal orientation and small modification to the aggregate morphology. SO_3H groups could change the crystal orientation and morphology effectively. The aggregates are pseudo-spherical and the face perpendicularity to the face (104) parallels to the surface of the aggregates.

  8. Effects of Pretreatment Conditions on Redox Property over Au/Co3O4/CeO2 Material

    Institute of Scientific and Technical Information of China (English)

    SHAO Jian-jun; MA Xiao-lei; ZHU Xi

    2009-01-01

    Au/Co3O4/CeO2 materials are prepared using conventional deposition-precipitation method. The effects of calcination temperatures and pretreatment conditions on the catalytic performance of Au/Co3O4/CeO2 for CO low-temperature oxidation in humid circumstance are investigated. The sample calcines at 443 K in flowing air exhibited good activity and stability for CO oxidation. 80% CO conversion rate can be achieved after 3 000 min with a feed gas contained 3.1%(φw) of water vapor. The physical and chemical properties of the Au/Co3O4/CeO2 samples are characterized by X-ray diffraction (XRD), temperature-programmed reduction (H2-TPR), and transmission electron microscopy (TEM) techniques. The characterized results show that the prepared material calcined at 443 K has a weak diffraction peak of gold species observed by XRD, the grain diameter of 3 nm by TEM and best redox property and the highest activity for CO oxidation by H2-TPR at prope calcined temperature.

  9. EFFECT OF PROCESSING METHOD ON THE IMPACT STRENGTH OF POM/TPU/CaCO3 TERNARY COMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Xiao-ling Gao; Cheng Qu; Qin Zhang; Rong-ni Du; Qiang Fu

    2005-01-01

    Polyoxymethylene (POM)/elastomer/filler ternary composites were prepared, in which thermoplastic polyurethane (TPU) and inorganic filler, namely, CaCO3, were used to achieve balanced mechanical properties of POM. The dispersion and phase morphology of POM/elastomer/filler composites were found to depend largely on processing method, CaCO3content in masterbatch and the filler size. Two processing methods were employed to prepare POM/elastomer/filler ternary composites. One is called the one-step method, in which elastomer and the filler directly melt blended with POM matrix. The other is called the two-step method, in which the elastomer and the filler were mixed to get masterbatch first, which was then melt blended with pure POM of different content. The effect of phase morphology and processing method on impact strength was investigated. It was found that the two-step method results in an increase in impact strength but not for the one-step method. Additionally, the impact strength of POM ternary composites decreases with the increase in the size of CaCO3particles.

  10. Bio-plastic (P-3HB-co-3HV) from Bacillus circulans (MTCC 8167) and its biodegradation.

    Science.gov (United States)

    Phukon, Pinkee; Saikia, Jyoti Prasad; Konwar, Bolin Kumar

    2012-04-01

    Polyhydroxyalkanoates (PHAs) are naturally occurring polyesters synthesized by bacteria for carbon and energy storage and it has commercial potential as bioplastic. The bacterial species Bacillus circulans MTCC 8167, isolated from crude oil contaminated soil, can efficiently produce medium chain length polyhydroxyalkanoates (P-3HB-co-3HV) from cheap carbon sources like dextrose. The molecular mass of P-3HB-co-3HV was reported as 5.1×10(4)Da with polydispersity index of 1.21 by gel permeation chromatography. In the present investigation different bacteria and fungi species were used for testing the biodegradability of the extracted polymer. The FTIR spectra of the biodegraded PHBV film showed a decrease in the peak from 1735 cm(-1) (untreated film) to 1675 cm(-1), and disappearance of a peak present in the control at 2922 cm(-1) indicating the breakdown of ester (>C=O) or O-R group and -C=H bond, respectively. From biodegradability testing, the tested microorganisms were found to have decisive contribution to the biodegradation of P-3HB-co-3HV polymer.

  11. Enhanced rate performance of mesoporous Co3O4 nanosheet supercapacitor electrodes by hydrous RuO2 nanoparticle decoration

    KAUST Repository

    Baby, Rakhi Raghavan

    2014-03-26

    Mesoporous cobalt oxide (Co3O4) nanosheet electrode arrays are directly grown over flexible carbon paper substrates using an economical and scalable two-step process for supercapacitor applications. The interconnected nanosheet arrays form a three-dimensional network with exceptional supercapacitor performance in standard two electrode configuration. Dramatic improvement in the rate capacity of the Co3O4 nanosheets is achieved by electrodeposition of nanocrystalline, hydrous RuO 2 nanoparticles dispersed on the Co3O4 nanosheets. An optimum RuO2 electrodeposition time is found to result in the best supercapacitor performance, where the controlled morphology of the electrode provides a balance between good conductivity and efficient electrolyte access to the RuO2 nanoparticles. An excellent specific capacitance of 905 F/g at 1 A/g is obtained, and a nearly constant rate performance of 78% is achieved at current density ranging from 1 to 40 A/g. The sample could retain more than 96% of its maximum capacitance even after 5000 continuous charge-discharge cycles at a constant high current density of 10 A/g. Thicker RuO2 coating, while maintaining good conductivity, results in agglomeration, decreasing electrolyte access to active material and hence the capacitive performance. © 2014 American Chemical Society.

  12. Super-high photocatalytic activity of Fe2O3 nanoparticles anchored on Bi2O2CO3 nanosheets with exposed {0 0 1} active facets

    Science.gov (United States)

    Hu, Dandan; Zhang, Kaiyou; Yang, Qi; Wang, Mingjun; Xi, Yi; Hu, Chenguo

    2014-10-01

    Structure engineering enables us to design novel photocatalysts with high efficiency and stability. Here visible light absorbing Fe2O3 semiconductor is chosen as sensitizer to modify wide band-gap Bi2O2CO3 semiconductor in order to enhance its photocatalytic properties by shifting the UV-driven catalytic activity to visible-light-driven catalytic activity. The Bi2O2CO3@Fe2O3 nanosheets with exposed active {0 0 1} facet were fabricated by a facile one-step modified hydrothermal method. The thermal stability, crystal structure, morphology and optical band gap were characterized. The photocatalytic activities of the Bi2O2CO3 and Bi2O2CO3@Fe2O3 with different molar ratio of Fe2O3 to Bi2O2CO3 were compared. It was found that the Bi2O2CO3@Fe2O3 catalyst can degrade rhodamine-B within 25 min under the simulated sunlight, displaying greatly enhanced photocatalytic activity with respect to the Bi2O2CO3 catalyst. The photocatalyst showed good photostability and recyclability. A mixture of multi-colored dyes including rhodamine-B, methylene blue and methyl orange can be completely degraded by the Bi2O2CO3@Fe2O3 catalyst (5 mol% Fe2O3) within 45 min under the simulated sunlight irradiation. The photocatalytic mechanism was discussed in detail.

  13. Interfacial effect of the nanostructured Ag2S/Co3O4 and its catalytic mechanism for the dye photodegradation under visible light

    Science.gov (United States)

    Qiu, X. P.; Yu, J. S.; Xu, H. M.; Chen, W. X.; Hu, W.; Bai, H. Y.; Chen, G. L.

    2016-01-01

    In this study, the synthesis of a highly hybrid, heterogeneously structured nanocomposite catalyst consisting of Ag2S nanoparticles dotted on a Co3O4 microrod array is reported. The average diameter and length of the Co3O4 microrods was optimized to be approximately 300 nm and 20 μm, respectively, and the average size of the Ag2S nanoparticles was approximately 10 nm. When the Ag2S nanoparticles were deposited on the Co3O4 microrods, the characteristic optical band gap energy of Co3O4 decreased from 1.26 eV to 1.23 eV, and the intensity of the absorbance peak at 650 nm increased significantly. The catalytic activity of nanosized Ag2S/Co3O4 for the photodegradation of organic contaminants with potassium hydrogen persulfate (PMS) or ozone (O3) was evaluated using basic green 1 dye (BG1) as a model pollutant. In the presence of the hybrid Ag2S/Co3O4 catalyst developed in this study, the complete photodegradation of the BG1 solution was achieved in 20 min and 6 min when PMS and O3 were used, respectively. In addition, the experimental results suggest that the catalytic photodegradation of BG1 using the Ag2S/Co3O4/PMS and Ag2S/Co3O4/O3 processes was dominated by the rad OH and rad O2- radicals, respectively.

  14. Co3O4-CeO2/C as a Highly Active Electrocatalyst for Oxygen Reduction Reaction in Al-Air Batteries.

    Science.gov (United States)

    Liu, Kun; Huang, Xiaobing; Wang, Haiyan; Li, Fuzhi; Tang, Yougen; Li, Jingsha; Shao, Minhua

    2016-12-21

    Developing high-performance and low-cost electrocatalysts for oxygen reduction reaction (ORR) is still a great challenge for Al-air batteries. Herein, CeO2, a unique ORR promoter, was incorporated into ketjenblack (KB) supported Co3O4 catalyst. We developed a facile two-step hydrothermal approach to fabricate Co3O4-CeO2/KB as a high-performance ORR catalyst for Al-air batteries. The ORR activity of Co3O4/KB was significantly increased by mixing with CeO2 nanoparticles. In addition, the Co3O4-CeO2/KB showed a better electrocatalytic performance and stability than 20 wt % Pt/C in alkaline electrolytes, making it a good candidate for highly active ORR catalysts. Co3O4-CeO2/KB favored a four-electron pathway in ORR due to the synergistic interactions between CeO2 and Co3O4. In full cell tests, the Co3O4-CeO2/KB exhibited a higher discharge voltage plateau than CeO2/KB and Co3O4/KB when used in cathode in Al-air batteries.

  15. Size Controlled Two-dimensional Co3O4 with Exposure of {111} Plane: Synthesis and Catalytic Properties for Photooxidation of Organics

    Science.gov (United States)

    The size controlled 2D hexagonal structured Co3O4 with exposure of the {111} plane was fabricated, and the catalytic properties for photooxidation of organics using as-prepared samples were investigated. 2D hexagonal structured Co3O4 with the size of 3 m displays higher photocat...

  16. Performance of lime-BHA solidified plating sludge in the presence of Na2SiO3 and Na2CO3.

    Science.gov (United States)

    Piyapanuwat, Rungroj; Asavapisit, Suwimol

    2011-09-01

    This research investigated the performance of lime-BHA (black rice husk ash) solidified plating sludge with 2 wt% NaO from Na(2)SiO(3) and Na(2)CO(3) at the level of 0, 30 and 50 wt%. The sludge was evaluated for strength development, leachability, solution chemistry and microstructure. The lime-BHA solidified plating sludge with Na(2)SiO(3) and Na(2)CO(3) had higher early strength when compared to the control. The addition of Na(2)SiO(3) and Na(2)CO(3) increased the OH(-) concentration and decreased the Ca(2+) and heavy metal ions in solution after the first minute. The XRD patterns showed that the addition of Na(2)SiO(3) resulted in the formation of calcium silicate hydrates, while the addition of Na(2)CO(3) resulted in CaCO(3). The heavy metals from the plating sludge, especially Zn, were immobilized in calcium zincate and calcium zinc silicate forms for the lime-BHA with and without Na(2)SiO(3) solidified wastes, while samples with Na(2)CO(3) contained Zn that was fixed in the form of CaZnCO(3). The cumulative leaching of Fe, Cr and Zn from the lime-BHA solidified plating sludge decreased significantly when activators were added, especially Na(2)CO(3).

  17. Influence of Functionalized Pyridine Ligands on the Radio/Chemical Behavior of [MI(CO)3]+ (M = Re and 99mTc) 2 + 1 Complexes

    Science.gov (United States)

    While a number of chelate strategies have been developed for the organometallic precursor fac-[M (OH2)3(CO)3]+ (M = Re, 99mTc), a unique challenge has been to improve the overall function and performance of these complexes for in vivo and in vitro applications. Since its synthesis, the fac-[M (CO)3]...

  18. The Effects of CaCO3 Coated Wood Free Paper Usage as Filler on Water Absorption, Mechanical and Thermal Properties of Cellulose-High Density Polyethylene Composites

    Directory of Open Access Journals (Sweden)

    Emrah PEŞMAN

    2016-11-01

    Full Text Available In this study some physical, mechanical and thermal characteristics of high density polyethylene (HDPE and CaCO3 coated/pigmented wood free paper fiber composites were investigated. The fillers used in this study were uncoated cellulose, 5.8 %, 11.5 %, 16.5 % and 23.1 % CaCO3 coated wood free paper fibers. Each filler type was mixed with HDPE at 40% by weight fiber loading. In this case, the ratio of CaCO3 in plastic composites were calculated as 0 %, 2.3 %, 4.6 %, 6.6 % and 9.2 % respectively. Increased CaCO3 ratio improved the moisture resistant, flexural and tensile strength of cellulose-HDPE composites. However, the density of the cellulose-HDPE composites increased with CaCO3 addition. Energy Dispersive Spectroscopy on Scanning Electron Microscope analysis demonstrated the uniform distribution of CaCO3 and cellulose fiber in plastic matrix. In addition, the thermal properties of fiber plastic composites were investigated. The results of Differential scanning calorimetry analysis revealed that the crystallinity of the samples decreased with increasing CaCO3 content. Consequently, this work showed that CaCO3 coated waste paper fibers could be used as reinforcing filler against water absorption in thermoplastic matrix.DOI: http://dx.doi.org/10.5755/j01.ms.22.4.14222

  19. Carbon and Binder-Free Air Electrodes Composed of Co3O 4 Nanofibers for Li-Air Batteries with Enhanced Cyclic Performance.

    Science.gov (United States)

    Lee, Chan Kyu; Park, Yong Joon

    2015-12-01

    In this study, to fabricate a carbon free (C-free) air electrode, Co3O4 nanofibers were grown directly on a Ni mesh to obtain Co3O4 with a high surface area and good contact with the current collector (the Ni mesh). In Li-air cells, any C present in the air electrode promotes unwanted side reactions. Therefore, the air electrode composed of only Co3O4 nanofibers (i.e., C-free) was expected to suppress these side reactions, such as the decomposition of the electrolyte and formation of Li2CO3, which would in turn enhance the cyclic performance of the cell. As predicted, the Co3O4-nanofiber electrode successfully reduced the accumulation of reaction products during cycling, which was achieved through the suppression of unwanted side reactions. In addition, the cyclic performance of the Li-air cell was superior to that of a standard electrode composed of carbonaceous material.

  20. 纳米碳酸钙在PVC型材中应用研究%Application of Nano-Calcium Carbonate (CaCO3) to PVC Profile

    Institute of Scientific and Technical Information of China (English)

    王道俊

    2007-01-01

    研究纳米碳酸钙(CaCO3)在PVC/CPE体系中的应用,讨论了改进前后纳米CaCO3对PVC体系流变行为的影响,并测试了纳米CaCO3对型材性能的影响.结果表明,改进后纳米CaCO3 P100流变性接近生产试样,可用于挤出生产;改进后的纳米CaCO3显著提高了型材的性能,可增韧增强PVC复合体系.

  1. Preparation of ultrafine Co3O4 powders by continuous and controllable combustion synthesis%连续和可控的燃烧法合成Co3O4超细粉

    Institute of Scientific and Technical Information of China (English)

    吴冲浒

    2011-01-01

    结合气固流态化和燃烧合成理论,提出连续动态可控燃烧合成概念.在自主设计、制作的气固流态床设备中,将CoC2O4·2H2O制备成Co3O4.反应物CoC2O4·2H2O粉体和空气分别以一定的速度被从沸腾床的上部加入和底部引入.CoC2O4·2H2O和空气在床层中相遇,并在给定的低温下被点燃并合成Co3O4.结果表明:燃烧波模式与传统燃烧合成燃烧波的不同,在连续动态可控燃烧合成中,燃烧波位置相对不动,悬浮在沸腾床中部的燃烧区域,而不是移动的自蔓延燃烧波;燃烧波温度可以通过改变载气流速、流量进行调节;产物Co3O4粉末(≤0.8 μm)呈球形或准球形,粒度分布均匀.本方法具有连续高效、节能环保的优点,已经应用于大规模生产.%The continuously dynamic-controlled combustion synthesis (CDCCS) was developed based on the continuous fluidization and combustion synthesis technologies. CoC2O4·2H2O powders were transformed to Co3O4 in a gas-solid fluid bed trnit designed and build independently,where the reactant of COC2O4·2H2O powders and the reactant of air were poured and introduced from the top and the bottom of the bed at a certain rates respectively. The reagents met in the bed and ignited at a given low temperature,resulting in formation of Co3O4. The results show a significant difference in combustion wave models. In the case of CDCCS,there was an immobile combustion wave,floating in the combustion zone located in the middle of the bed,instead of propagating of the combustion wave. The temperature of the combustion wave can be controlled by adjusting the flow rate of carrier gas. The resultant Co3O4 powders (diameter size ≤0.8 μm) have a narrow particle size distribution and spherical or quasi-spherical shape. This novel technique has many advantages,such as continuation,efficiency,energy conservation and environmental friendly and has been used in mass production.

  2. Interfacial effects of the Cu2O nano-dots decorated Co3O4 nanorods array and its photocatalytic activity for cleaving organic molecules

    Science.gov (United States)

    Qiu, X. P.; Yu, J. S.; Xu, H. M.; Chen, W. X.; Hu, W.; Chen, G. L.

    2016-09-01

    A heterogeneous nanocomposite catalyst constructed by the Co3O4 nanorods decorated with the Cu2O quantum dots (QDs) were successfully synthesized via a simple hydrothermal method followed by an oxidation-reduction processing. The fabricated Cu2O/Co3O4 nanocomposite was characterized by the SEM, TEM, XPS, XRD, UV-vis and PL, and the (2 2 0) and (3 1 1) facets of the Co3O4 were exposed. Compared with the original Co3O4 nanorods with an average diameter of 350 nm, a substantial decrease in the band gap was observed after doping the nanorods with the Cu2O QDs (average diameter of 5 nm). Such a dramatic decrease in the band gap indicated a significant enhancement of the photocatalytic activities under visible light. The methylene blue (MB) dye and the phenol were used as model organic pollutants, and the Cu2O/Co3O4 nanocomposite catalyst exhibited both high catalytic activity and good recycling stability. The catalytic activities of the Cu2O/Co3O4/potassium monopersulfate triple salt (PMS) system for cleaving the MB and the phenol were dependent on the dosages of the Cu2O QDs, and the calculated degradation rates achieved by 7.0 wt% Cu2O/Co3O4 nanocomposite catalyst were about 11.3 and 1.8 times than that of the pristine Co3O4 nanorod catalyst for the MB and the phenol, respectively. The reactive species of rad O2- and the holes were determined to be the main active species for the phenol photocatalytic degradation by the 7 wt% Cu2O/Co3O4/PMS system and the 7 wt% Cu2O/Co3O4/H2O2 system, respectively.

  3. PVC/CPE/nano-CaCO3复合材料的性能研究%Performance study on PVC/CPE/nano-CaCO3 composite material

    Institute of Scientific and Technical Information of China (English)

    王玉龙; 杨琳; 王勇; 陈勤; 丁武绿; 李振中

    2015-01-01

    通过熔融共混法制备了不同配方含量的PVC/CPE/nano-CaCO3复合材料,并对其力学性能、耐热性能和热性能进行了分析,研究了不同碳酸钙含量对复合材料的拉伸强度、冲击强度、维卡软化点温度和热分解温度的影响规律.

  4. Co3O4/Co-N-C modified ketjenblack carbon as an advanced electrocatalyst for Al-air batteries

    Science.gov (United States)

    Li, Jingsha; Zhou, Zhi; Liu, Kun; Li, Fuzhi; Peng, Zhiguang; Tang, Yougen; Wang, Haiyan

    2017-03-01

    Nitrogen-doped carbon materials containing non-precious metal (TM-N-C) and Co-based oxides have been extensively investigated as promising catalysts for oxygen reduction reaction (ORR). Herein, we report a novel Co3O4/Co-N-C modified ketjenblack carbon (KB) catalyst via a one-pot and scalable pyrolysis process using cheap melamine, cobalt acetate tetrahydrate and KB as raw materials. Owing to the high specific surface area and good electrical conductivity, this KB-based catalyst exhibits remarkable catalytic activity with a half-wave potential of 0.798 V (vs RHE) and a limiting current density of 5.10 mA cm-2 in alkaline solution, which are comparable with those of the commercial 20 wt% Pt/C. More importantly, it displays superior stability to Pt/C, which makes it one of the most promising non-noble-metal catalysts. Al-air batteries with this catalyst are also tested and generate a maximum power density of 161.1 mW cm-2, which is close to that with 20 wt% Pt/C catalyst (161.9 mW cm-2). After the discharge for 18 h at 50 mA cm-2, the voltage degradation of Al-air battery with Co3O4/Co-N-C modified KB is 7%, while that using Pt/C is increased to 12%. By virtues of its remarkable performance, low cost and simple fabrication method, Co3O4/Co-N-C modified KB here can be used as an efficient ORR cathode catalyst instead of the commercial Pt/C for practical Al-air batteries.

  5. Síntesis de MgAl2O4 a baja temperatura con adiciones de CaCO3

    OpenAIRE

    Aguilar Garib, Juan Antonio; Arato Tovar, Ana María.; Hinojosa Rivera, Moisés

    2004-01-01

    A partir de que la espinela MgAl2O4 fue propuesta como material sustituto de refractarios basados en cromo, los fabricantes han promovido la busqueda de alternativas para producirla. Los aditivos han sido empleados ampliamente como un método para reducir las temperaturas de procesamiento. Se estudiaron mezclas en una relaciÛn 1:1 molar de MgO y Al2O3 con diferentes concentraciones de CaCO3. Las pruebas fueron llevadas a cabo en un horno de resistencia eléctrica a 1400°C, y las fases formadas ...

  6. Ligand free copper(I)-catalyzed synthesis of diaryl ether with Cs2CO3 via a free radical path.

    Science.gov (United States)

    Chen, Hong-Jie; Tseng, Mei-Chun; Hsu, I-Jui; Chen, Wei-Ting; Han, Chien-Chung; Shyu, Shin-Guang

    2015-07-21

    Complexes [Cu(I)(2,4-dimethylphenoxy)2](-) (A) and [Cu(II)(2,4-dimethylphenoxy)2(p-tolyl)](-) (B) were observed by in situ electrospray ionization mass spectrometry (ESI-MS) analysis of the ligand free copper(I)-catalyzed C-O coupling reaction using Cs2CO3 under the catalytic reaction conditions indicating that they could be intermediates in the reaction. The radical scavenger cumene retarded the reaction. Catalytic cycles involving a free radical path are proposed based on these observations.

  7. Electrodeposition of BaCO3 coatings on stainless steel substrates: Oriented growth in the presence of complexing agents

    Indian Academy of Sciences (India)

    Sumy Joseph; Sarala Upadhya; P Vishnu Kamath

    2009-09-01

    Electrodeposition of BaCO3 from aminecarboxylate stabilized-Ba(HCO3)2 baths, results in oriented crystallization when the bath conditions promote the decomposition of the Ba complex. Crystal growth is predominant along the -crystallographic axis. The crystallites orient themselves with their -axis normal to the substrate. The crystallites exhibit three-fold twinning (trilling) consequent to the evolution of the {110} planes as planes of reflection. Pairs of trillings are seen to grow about a four-sided polygon formed by the {010} crystal faces whose centre is a point of inversion.

  8. Brief communication: ikaite (CaCO3*6H2O discovered in Arctic sea ice

    Directory of Open Access Journals (Sweden)

    M. A. Granskog

    2010-02-01

    Full Text Available We report for the first time on the discovery of calcium carbonate crystals as ikaite (CaCO3*6H2O in sea ice from the Arctic (Kongsfjorden, Svalbard. This finding demonstrates that the precipitation of calcium carbonate during the freezing of sea ice is not restricted to the Antarctic, where it was observed for the first time in 2008. This finding is an important step in the quest to quantify its impact on the sea ice driven carbon cycle and should in the future enable improvement parametrization sea ice carbon models.

  9. Polar coralline algal CaCO3-production rates correspond to intensity and duration of the solar radiation

    Science.gov (United States)

    Teichert, S.; Freiwald, A.

    2014-02-01

    In this study we present a comparative quantification of CaCO3 production rates by rhodolith-forming coralline red algal communities situated in high polar latitudes and assess which environmental parameters control these production rates. The present rhodoliths act as ecosystem engineers, and their carbonate skeletons provide an important ecological niche to a variety of benthic organisms. The settings are distributed along the coasts of the Svalbard archipelago, being Floskjeret (78°18' N) in Isfjorden, Krossfjorden (79°08' N) at the eastern coast of Haakon VII Land, Mosselbukta (79°53' N) at the eastern coast of Mosselhalvøya, and Nordkappbukta (80°31' N) at the northern coast of Nordaustlandet. All sites feature Arctic climate and strong seasonality. The algal CaCO3 production rates were calculated from fuchsine-stained, presumably annual growth increments exhibited by the rhodoliths and range from 100.9 g (CaCO3) m-2 yr-1 at Nordkappbukta to 200.3 g (CaCO3) m-2 yr-1 at Floskjeret. The rates correlate to various environmental parameters with geographical latitude being the most significant (negative correlation, R2 = 0.95, p = 0.0070), followed by the duration of the polar night (negative correlation, R2 = 0.93, p = 0.0220), the duration of the sea ice cover (negative correlation, R2 = 0.87, p = 0.0657), and the annual mean temperature (positive correlation, R2 = 0.48, p = 0.0301). This points out sufficient light incidence to be the main control of the growth of the examined coralline red algal rhodolith communities, while temperature is less important. Thus, the ongoing global change with its rising temperatures will most likely result in impaired conditions for the algae, because the concomitant increased global runoff will decrease water transparency and hence light incidence at the four offshore sites. Regarding the aforementioned role of the rhodoliths as ecosystem engineers, the impact on the associated organisms will presumably also be negative.

  10. Cobalt incorporation in calcite: thermochemistry of (Ca,Co)CO3 solid solutions from density functional theory simulations

    Science.gov (United States)

    González-López, Jorge; Ruiz-Hernández, Sergio E.; Fernández-González, Ángeles; Jiménez, Amalia; de Leeuw, Nora H.; Grau-Crespo, Ricardo

    2015-04-01

    The incorporation of cobalt in mixed metal carbonates is a possible route to the immobilization of this toxic element in the environment. However, the thermodynamics of (Ca,Co)CO3 solid solutions are still unclear due to conflicting data from experiment and from the observation of natural ocurrences. Atomistic computer simulations, which allow the evaluation of thermodynamic properties without the interference of unknown kinetic factors, have been increasingly used in recent years for the investigation of the thermodynamics of mixing and impurity incorporation in carbonate. We report here the results of a computer simulation study of the mixing of calcite (CaCO3) and spherocobaltite (CoCO3), using density functional theory calculations. Our simulations suggest that previously proposed thermodynamic models, based only on observed compositions, significantly overestimate the solubility between the two solids and therefore underestimate the extension of the miscibility gap under ambient conditions. The enthalpy of mixing of the disordered solid solution is strongly positive and moderately asymmetric: calcium incorporation in spherocobaltite is more endothermic than cobalt incorporation in calcite. Ordering of the impurities in (0001) layers is energetically favourable with respect to the disordered solid solution at low temperatures and intermediate compositions, but the ordered phase is still unstable to demixing. The solvus and spinodal lines in the phase diagram using a sub-regular solution model has been also calculated, and conclude that many Ca1-xCoxCO3 mineral solid solutions (with observed compositions of up to x=0.027, and above x=0.93) are metastable with respect to phase separation. The strong non-ideality of this solid solution has an important effect on the solid solution / aqueous solution thermodynamic partitioning: the equilibrium level of substitutional impurities in the endmember solids is always low, regardless of the composition of the aqueous

  11. Inter-diffusion between Co3O4 coatings and the oxide scale on Fe-22Cr

    DEFF Research Database (Denmark)

    Hansson, Anette Nørgaard; Linderoth, Søren; Mogensen, Mogens Bjerg

    2007-01-01

    The oxidation behaviour of a commercially available Fe-22Cr alloy coated with a Co3O4 layer by spray-painting or plasma-spraying was investigated at 1173K in air with 1% H2O and compared to the oxidation behaviour of the non-coated alloy. The oxide morphology was examined with X-ray diffraction, ...... plasma-sprayed and the non-coated samples. The difference in morphology is suggested to be an effect of SiO2 nucleation assisted by Kirkendall void formation....

  12. Electrical conductivity of single molecular junctions assembled from Co- and Co3C-encapsulating carbon nanocapsules.

    Science.gov (United States)

    Matsuura, Daisuke; Kizuka, Tokushi

    2014-03-01

    Single molecular junctions (SMJs) were assembled from cobalt (Co)- and Co carbide (Co3C)-encapsulating carbon nanocapsules (CNCs) and two gold electrodes inside a high-resolution transmission electron microscope equipped with a specimen-piezomanipulation system. The structure and electrical transport properties of the SMJs were investigated in situ. The current density depended on the perimeter of the contact area between CNCs and the electrodes, showing that the current flowed not through the encapsulated region but rather along the graphene layers of CNCs. It was demonstrated that the properties of graphene can be applied to nanodevices using CNCs irrespective of the encapsulating materials.

  13. High-temperature thermoelectric properties of p-type skutterudites Ba0.15Yb x Co3FeSb12 and Yb y Co3FeSb9As3

    KAUST Repository

    Dong, Yongkwan

    2014-08-28

    Two series of p-type polycrystalline skutterudites, Ba0.15YbxCo3FeSb12 and YbyCo3FeSb9As3 with varying Yb concentrations, were synthesized by solid-state reaction and then densified by hot pressing. The phase and stoichiometries of the resulting materials were characterized by powder X-ray diffraction and energy dispersive spectroscopy, while their high-temperature transport properties were investigated from 300 to 800 K. The Seebeck coefficients and electrical resistivities increased linearly with increasing temperature for the double-filled specimens. The Seebeck coefficients and electrical resistivities did not change very much for the As-substituted specimens. The thermal conductivity for all specimens decreased with increasing temperature up to 700 K, corresponding to the plateau in the Seebeck coefficient, and then increased again due to bipolar diffusion. We find that double filling is a more feasible approach to thermoelectric property optimization than single filling with As substitution. © 2014 Springer Science+Business Media New York.

  14. 不同光照条件下Co3O4纳米粉体的光催化性能%Photocatalytic Properties of Co3O4 Nano-Powder Under Different Illumination Conditions

    Institute of Scientific and Technical Information of China (English)

    王天喜; 刘双枝

    2012-01-01

    用沉淀-热解法制备Co3O4纳米粉体,并对其进行XRD和扫描电镜分析.分别使用300W高压汞灯及模拟可见光的氙灯为光源,使用该催化剂对B-GFF黑等3种不同模拟染料废水进行光催化降解,取得了较好的效果.实验结果表明,Co3O4催化剂在高压汞灯照射下有较好的光催化效果;在模拟可见光的氙灯条件下,也具有明显的光催化效果,具有一定的对可见光的利用能力,有很好的实际开发应用价值.

  15. 改性纳米CaCO3/PE-g-MAH/HDPE复合塑料拉伸性能研究%Tensile properties of nano-CaCO3/PE-g-MAH/HDPE composite plastic

    Institute of Scientific and Technical Information of China (English)

    戴欣; 尚庆坤; 李诗春; 修艳华; 冯雪娇; 傅高峰

    2007-01-01

    采用硬脂酸(SA)对纳米进行表面活化,考察了改性纳米CaCO3、马来酸酐接枝聚乙烯(PE-g-MAH)分别或共同添加到高密度聚乙烯(HDPE)中形成的复合塑料的拉伸性能.结果表明:用质量分数为7%硬脂酸改性的纳米CaCO3,能较好地促使无机粒子的分散和与HDPE的结合,提高复合塑料的拉伸性能.PE-g-MAH的进一步嫁接作用,可延长硬脂酸分子链,加强硬脂酸和基体树脂之间的缠结作用,从而显著提高了复合塑料的拉伸强度.

  16. Enhanced Visible Light Photocatalytic Degradation of Organic Pollutants over Flower-Like Bi2O2CO3 Dotted with Ag@AgBr

    Directory of Open Access Journals (Sweden)

    Shuanglong Lin

    2016-10-01

    Full Text Available A facile and feasible oil-in-water self-assembly approach was developed to synthesize flower-like Ag@AgBr/Bi2O2CO3 micro-composites. The photocatalytic activities of the samples were evaluated through methylene blue degradation under visible light irradiation. Compared to Bi2O2CO3, flower-like Ag@AgBr/Bi2O2CO3 micro-composites show enhanced photocatalytic activities. In addition, results indicate that both the physicochemical properties and associated photocatalytic activities of Ag@AgBr/Bi2O2CO3 composites are shown to be dependent on the loading quantity of Ag@AgBr. The highest photocatalytic performance was achieved at 7 wt % Ag@AgBr, degrading 95.18% methylene blue (MB after 20 min of irradiation, which is over 1.52 and 3.56 times more efficient than that of pure Ag@AgBr and pure Bi2O2CO3, respectively. Bisphenol A (BPA was also degraded to further demonstrate the degradation ability of Ag@AgBr/Bi2O2CO3. A photocatalytic mechanism for the degradation of organic compounds over Ag@AgBr/Bi2O2CO3 was proposed. Results from this study illustrate an entirely new approach to fabricate semiconductor composites containing Ag@AgX/bismuth (X = a halogen.

  17. Facile synthesis of surface N-doped Bi2O2CO3: Origin of visible light photocatalytic activity and in situ DRIFTS studies.

    Science.gov (United States)

    Zhou, Ying; Zhao, Ziyan; Wang, Fang; Cao, Kun; Doronkin, Dmitry E; Dong, Fan; Grunwaldt, Jan-Dierk

    2016-04-15

    Bi2O2CO3 nanosheets with exposed {001} facets were prepared by a facile room temperature chemical method. Due to the high oxygen atom density in {001} facets of Bi2O2CO3, the addition of cetyltrimethylammonium bromide (CTAB) does not only influence the growth of crystalline Bi2O2CO3, but also modifies the surface properties of Bi2O2CO3 through the interaction between CTAB and Bi2O2CO3. Nitrogen from CTAB as dopant interstitially incorporates in the Bi2O2CO3 surface evidenced by both experimental and theoretical investigations. Hence, the formation of localized states from NO bond improves the visible light absorption and charge separation efficiency, which leads to an enhancement of visible light photocatalytic activity toward to the degradation of Rhodamine B (RhB) and oxidation of NO. In addition, the photocatalytic NO oxidation over Bi2O2CO3 nanosheets was successfully monitored for the first time using in situ diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS). Both bidentate and monodentate nitrates were identified on the surface of catalysts during the photocatalytic reaction process. The application of this strategy to another relevant bismuth based photocatalyst, BiOCl, demonstrated that surface interstitial N doping could also be achieved in this case. Therefore, our current route seems to be a general option to modify the surface properties of bismuth based photocatalysts.

  18. Biogenic CaCO3 and Opal Depositions and Their Latitudinal Comparison During the Past 600 ka in the Central Equatorial Pacific

    Directory of Open Access Journals (Sweden)

    Boo-Keun Khim

    2015-01-01

    Full Text Available The orbital-scale variations in biogenic CaCO3 and opal abundance in two piston cores collected in the central equatorial Pacific (core PC5101 from a southern site at _ and core PC5103 from a northern site at _ were compared to assess latitudinal differences. The correlation between the oxygen isotope stratigraphy of planktonic foraminifera (Globigerinoides sacculifer of PC5103 with the LR04 stacks provides the age of PC5103 to be approximately 950 ka. The age of PC5103 was further refined by correlating the CaCO3 content with the well-dated core RC11-210. The age of PC5101 was also constrained by the same CaCO3 chronostratigraphic correlation with RC11-210, resulting in an age of approximately 650 ka. Distinct orbital-scale series of CaCO3 and opal variations appear to be parallel between the two cores during the past 600 ka, which are controlled mainly by eccentricity with an approximate periodicity of 100 ka. It is worth noting that the biogenic CaCO3 and opal deposition patterns in the two cores differ between interglacial and glacial periods. During interglacial periods the biogenic opal content is higher in the southern core than in the northern core, which corresponds with the present-day condition. In contrast the CaCO3 content is higher in the northern core, which is contradictory to the present-day northward decreasing CaCO3 deposition pattern from the Equator. The collection site of PC5101 is approximately 350 m deeper than that of PC5103, which significantly promotes CaCO3 dissolution and causes unexpectedly high CaCO3 content at the northern site in contrast to the biogenic opal content.

  19. 纳米碳酸钙改性PA6性能的研究%Study on Properties of Nano-CaCO3 Modiifed PA6

    Institute of Scientific and Technical Information of China (English)

    梁秀丽; 王建国; 茅燕燕; 吕辉; 郭红枫; 陈斌; 王强

    2016-01-01

    Nano-CaCO3 modified PA6 was prepared with nano-CaCO3 blending PA6. The influence of nano-CaCO3 content on properties of the modified PA6 were studied and it was characterized by FTIR. The results show that with the content of nano-CaCO3 increasing, the hardness, bending strength and thermal deformation temperature increase and the size stability improves, tensile and impact strength reduce, the difference in infrared spectrum is not obvious.%采用纳米CaCO3与尼龙(PA)6共混,制备纳米CaCO3改性PA6材料。研究纳米CaCO3含量对改性PA6性能的影响,并对其进行了傅立叶变换红外光谱(FTIR)表征。结果表明,随着纳米CaCO3含量的增加,改性PA6材料的硬度、弯曲强度、热变形温度有了提高,尺寸稳定性有所改善,拉伸和冲击性能有所下降,对于不同含量的纳米CaCO3改性PA6材料,表现在FTIR谱图上的差异并不明显。

  20. Natural polymorphisms of HIV-1 CRF01_AE integrase coding region in ARV-naïve individuals in Cambodia, Thailand and Vietnam: an ANRS AC12 working group study.

    Science.gov (United States)

    Nouhin, Janin; Donchai, Tawee; Hoang, Khanh Thu Huynh; Ken, Sreymom; Kamkorn, Jiraporn; Tran, Ton; Ayouba, Ahidjo; Peeters, Martine; Chaix, Marie-Laure; Lien, Truong Xuan; Nerrienet, Eric; Ngo-Giang-Huong, Nicole

    2011-01-01

    The HIV integrase enzyme is essential for the HIV life cycle as it mediates integration of HIV-1 proviral DNA into the infected cell's genome. Recently, the development of drugs capable of inhibiting integrase has provided major new options for HIV-infected, treatment-experienced patients with multidrug resistant virus, as well treatment-naïve patients. More than 40 amino acid substitutions within integrase have been described as associated mostly with resistance of HIV B-subtypes to currently available integrase inhibitors (INIs). We have analyzed the natural polymorphisms of the integrase coding region in 87 antiretroviral-naïve subjects (32 from Cambodia, 37 from Thailand and 18 from Vietnam) infected with CRF01_AE virus, the predominant HIV-1 strain circulating in Southeast Asia. The 864bp integrase coding region was sequenced using the ANRS consensus sequencing technique from plasma samples, and amino acid results were interpreted for drug resistance according to the ANRS (Updated July 2009, version 18) and Stanford algorithms (Version November 6, 2009). Alignment of the 87 amino acid sequences against the 2004 Los Alamos HIV-1 clade B consensus sequence showed that overall, 119 of 288 (41.3%) amino acid positions presented at least one polymorphism each. Substitutions found in >60% of study subjects occurred at: K14, A21, V31, S39, I72, T112, T124, T125, G134, I135, K136, D167, V201, L234 and S283. Also, new amino acid substitutions of as yet unknown significance were identified: E152K/H, S153F/L, N155I and E157G. None of the known integrase resistance mutations were observed, except E157Q found in one Cambodian subject (1.1%, CI 95% 0.02-6.3%). The clinical impact of this substitution on resistance of B and nonB-viruses to the licensed INI raltegravir is unclear. If this substitution is confirmed to compromise the virologic response to raltegravir, further studies will be needed to better assess the prevalence of this substitution among CRF01_AE virus.

  1. 纳米CaCO3/聚合物复合材料及其在建筑塑料中的应用研究%Nano CaCO3/polymer composite material and its application research in building plastics

    Institute of Scientific and Technical Information of China (English)

    王国全; 赵红英; 陈建峰; 曾晓飞

    2002-01-01

    研究了纳米CaCO3/PVC/CPE以及纳米CaCO3/PP/SBS复合材料的力学性能,结果表明:纳米CaCO3对PVC共混体系具有显著的增韧效果,对PP共混体系也有一定的增韧效果.并研究了纳米CaCO3/PVC/CPE复合材料在PVC门窗异型材中的应用.

  2. Multi-Phase Reactions and Crystal Types of Precipitated Calcium Carbonate%多相反应与沉淀CaCO3的晶型

    Institute of Scientific and Technical Information of China (English)

    方卫民

    2001-01-01

    讨论了在多相反应系统中反应温度、CO2浓度和搅拌速度等对沉淀CaCO3晶型和粒径的影响.测定了反应过程中碳化率和电导率的相关变化.实验表明,在30℃以下可获得立方体CaCO3沉淀,在30℃以上可获得纺锤型CaCO3沉淀.

  3. Effect of mixed rare earth oxides and CaCO3 modification on the microstructure of an in-situ Mg2Si/Al-Si composite

    Institute of Scientific and Technical Information of China (English)

    LIU Zheng; LIN Jixing; JING Qingxiu

    2009-01-01

    The effects of mixed rare earth oxides and CaCO3 on the microstructure of an in-situ Mg2Si/Al-Si hypereutectic alloy composite were investigated by optical microscope, scanning electron microscope, and energy dispersive spectrum analysis. The results showed that the morphology of the primary Mg2Si phase particles changed from irregular or crosses to polygonal shape, their sizes decreased from 75 μm to about 25 μm, and the compound of both the oxide and CaCO3 was better than either the single mixed rare earth oxides or CaCO3.

  4. Electrophoretic deposition of (Mn,Co)3O4 spinel coating for solid oxide fuel cell interconnects

    Science.gov (United States)

    Zhang, Hui; Zhan, Zhaolin; Liu, Xingbo

    2011-10-01

    We discuss here our attempt to develop (Mn,Co)3O4 spinel coatings on the surface of Cr-containing steel through electrophoretic deposition (EPD) followed by reduced-atmosphere sintering for solid oxide fuel cell (SOFC) interconnect application. The effects of EPD voltages and sintering atmospheres on the microstructure, electrical conductivity and long-term stability of the coated interconnects are examined by means of scanning electron microscopy (SEM), energy dispersion spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), and four-probe resistance techniques. For the spinel coatings generated using smaller voltage than 400 V, the interconnect surfaces exhibit good packing behavior and high conductivity. The reduced atmosphere during sintering has a beneficial impact on the minimizing chromia subscale formation and thus reducing the area specific resistance (ASR) of the coated interconnects. Moreover, it is interesting to note that a more stable long-term performance is achieved for the spinel coating sintered in H2/H2O atmosphere with thin chromia sub-scale and no Cr penetration. Based on the current results, EPD followed by reduced-atmosphere sintering is a fast and economic way to deposit (Mn,Co)3O4 coating for SOFC interconnect applications.

  5. Genome-engineered Sinorhizobium meliloti for the production of poly(lactic-co-3-hydroxybutyric) acid copolymer.

    Science.gov (United States)

    Tran, Tam T; Charles, Trevor C

    2016-02-01

    Economically competitive commercial production of biodegradable bioplastics with desirable properties is an important goal. In this study, we demonstrate the use of chromosome engineering of an alternative bacterial host, Sinorhizobium meliloti, for production of the copolymer, poly(lactate-co-3-hydroxybutyrate). Codon-optimized genes for 2 previously engineered enzymes, Clostridium propionicum propionate CoA transferase (Pct532Cp) and Pseudomonas sp. strain MBEL 6-19 polyhydroxyalkanoate (PHA) synthase 1 (PhaC1400Ps6-19), were introduced into S. meliloti Rm1021 by chromosome integration, replacing the native phbC gene. On the basis of phenotypic analysis and detection of polymer product by gas chromatography analysis, synthesis and accumulation of the copolymer was confirmed. The chromosome integrant strain, with the introduced genes under the control of the native phbC promoter, is able to produce over 15% cell dry mass of poly(lactate-co-3-hydroxybutyrate), containing 30 mol% lactate, from growth on mannitol. We were also able to purify the polymer from the culture and confirm the structure by NMR and GC-MS. To our knowledge, this is the first demonstration of production of this copolymer in the Alphaproteobacteria. Further optimization of this system may eventually yield strains that are able to produce economically viable commercial product.

  6. Surface Spins Pinning Effect on the Magnetic Properties in Co3O4 Nanocrystallites Covered with Polymer Decomposition Residues

    Institute of Scientific and Technical Information of China (English)

    李山东; 毕红; 方江邻; 钟伟; 都有为

    2004-01-01

    We prepare two kinds of Co3O4 antiferromagnetic nanocrystallite systems with different surface structures: one grain surface is covered by polymer decomposition residues (PDRs) (referred to as CS) and the other is naked (NS). It has been found that the magnetic properties of the CS sample deviate greatly from those of the NS sample. For example, the CS sample exhibits an open loop up to 8 T at 4.2K, while the two branches of the hysteresis loop for the NS sample superpose together when the field is in excess of 3 T. The average permanent magnetic moments per Co3O4 cell for the CS sample are about three times larger than that of the NS sample.The coercivity and loop shift for the CS sample are enhanced remarkably in comparison with the NS sample,i.e., from 73.8 and 11.0 kA/m for the NS sample to 116.5 and 25.5 kA/m for the CS sample, respectively. The anomalous magnetic properties and their enhancements for the CS sample are attributed to the surface spin pinning effect by PDRs.

  7. Synthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from unrelated carbon sources in engineered Rhodospirillum rubrum.

    Science.gov (United States)

    Heinrich, Daniel; Raberg, Matthias; Steinbüchel, Alexander

    2015-04-01

    Different genes encoding pyridine nucleotide transhydrogenases (pntAB, udhA) and acetoacetyl-CoA reductases (phaB) were heterologously overexpressed in Rhodospirillum rubrum S1. A recombinant strain, which harbored the gene encoding the membrane-bound transhydrogenase PntAB from Escherichia coli MG1655 and the phaB1 gene coding for an NADPH-dependent acetoacetyl-CoA reductase from Ralstonia eutropha H16, accumulated poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [Poly(3HB-co-3HV)] with a 3HV fraction of up to 13 mol% from fructose. This was a 13-fold increase of the 3HV content when compared to the wild-type strain. Higher contents of 3HV are known to reduce the brittleness of this polymer, which is advantageous for most applications. The engineered R. rubrum strain was also able to synthesize this industrially relevant copolymer from CO2 and CO from artificial synthesis gas (syngas) with a 3HV content of 56 mol%. The increased incorporation of 3HV was attributed to an excess of propionyl-CoA, which was generated from threonine and related amino acids to compensate for the intracellular redox imbalance resulting from the transhydrogenase reaction. Thereby, our study presents a novel, molecular approach to alter the composition of bacterial PHAs independently from external precursor supply. Moreover, this study also provides a promising production strain for syngas-derived second-generation biopolymers.

  8. Process for capturing CO2 arising from the calcination of the CaCO3 used in cement manufacture.

    Science.gov (United States)

    Rodríguez, N; Alonso, M; Grasa, G; Abanades, J Carlos

    2008-09-15

    This paper outlines a new CaCO3 calcination method for producing a stream of CO2 (suitable for permanent geological storage after purification and compression). The process is based on the use of very hot CaO particles (T >1000 degrees C) to transfer heat from a circulating fluidized bed combustor (CFBC) to a calciner (fluidized with CO2 and/or steam). Since the fluidized bed combustor and calciner have separate atmospheres, the CO2 resulting from the decomposition of CaCO3 can be captured, while the CO2 generated in the combustion of the fuel in air is emitted to the atmosphere. We demonstrate that with this system it is possible to reduce the CO2 emissions of a cement plant by around 60%. Furthermore, since the key pieces of equipment are similar to the commercial CFBCs used in power generation plants, it is possible to establish the additional investment required for the system and to estimate the cost per ton of CO2 avoided for this process to be about 19 $/tCO2 avoided.

  9. Kinetics of the Oxidative Dehydrogenation of Isobutane over Cr2O3/La2(CO3)3

    Institute of Scientific and Technical Information of China (English)

    Yanping Sun; Tracey A. Robson; Trevor C. Brown

    2002-01-01

    The oxidative dehydrogenation (ODH) of isobutane over Cr2O3/La2(CO3)3 has been investi-gated in a low-pressure Knudsen cell reactor, under conditions where the kinetics of the primary reactionsteps can be accurately determined. By heating the catalyst at a constant rate from 150-300 ℃, temper-ature fluctuations due to non-equilibrium adsorption are minimized. The evolved gas profiles show thatODH to isobutene and water is a primary reaction pathway, while carbon dioxide, which forms from thecatalyst during reaction, is the only other product. This CO2 evolution may enhance the activity of thecatalyst. Isobutene formation proceeds with the participation of lattice oxygen from the Cr2O3/La2(CO3)3catalyst. The intrinsic Arrhenius rate constant for the ODH of isobutane isk(s-1) = 1011.5±2.2exp{-((55 ± 5) - △Hads kJmol-1)/RT}The small pre-exponential factor is expected for a concerted mechanism and for such a catalyst with asmall surface area and limited porosity.

  10. Competitive removal of water-borne copper, zinc and cadmium by a CaCO3-dominated red mud.

    Science.gov (United States)

    Ma, Yingqun; Lin, Chuxia; Jiang, Yuehua; Lu, Wenzhou; Si, Chunhua; Liu, Yong

    2009-12-30

    Batch experiments were conducted to investigate the competitive removal of water-borne Cu, Zn and Cd by a CaCO(3)-dominated red mud. The results show that the water-borne Cu had a higher affinity to the red mud, as compared to the water-borne Zn and Cd. The major mechanism responsible for the preferential retention of Cu by red mud was the formation of atacamite. It is likely that, initially, atacamite was formed mainly through the reaction between CuCl(2) and NaOH. Reaction between CuCl(2) and CaCO(3) to form atacamite became more and more important with the gradual consumption of NaOH. Sequential extraction results show that the water-borne metals were preferentially associated with the NH(2)OH.HCl-extractable fractions at the early stage of the experiment. With increase in the saturation degree of binding sites on red mud particles by the metals, the proportion of HCH(3)COO-extractable Cu fraction increased accordingly. Water-borne Zn and Cd were also increasingly bound in the HCH(3)COO-extractable forms until the metal binding capacity of the red mud was nearly depleted. After the binding sites of red mud particles were saturated, part of the Zn and Cd previously retained by the red mud was displaced by water-borne Cu, resulting in the release of the previously immobilized Zn and Cd to the solution.

  11. Architecture of the organic matrix in the sternal CaCO3 deposits of Porcellio scaber (Crustacea, Isopoda).

    Science.gov (United States)

    Fabritius, Helge; Walther, Paul; Ziegler, Andreas

    2005-05-01

    Before the molt terrestrial isopods resorb calcium from the posterior cuticle and store it in large deposits within the first four anterior sternites. In Porcellio scaber the deposits consist of three structurally distinct layers consisting of amorphous CaCO3 (ACC) and an organic matrix that consists of concentric and radial elements. It is thought that the organic matrix plays a role in the structural organization of deposits and in the stabilization of ACC, which is unstable in vitro. In this paper, we present a thorough analysis of the ultrastructure of the organic matrix in the CaCO3 deposits using high-resolution field-emission scanning electron microscopy. The spherules and the homogeneous layer contain an elaborate organic matrix with similar structural organization consisting of concentric reticules and radial strands. The decalcification experiments reveal an inhomogeneous solubility of ACC within the spherules probably caused by variations in the stabilizing properties of matrix components. The transition between the three layers can be explained by changes in the number of spherule nucleation sites.

  12. High stenghth concrete with high cement substitution by adding fly ash, CaCO3, silica sand, and superplasticizer

    Science.gov (United States)

    Wicaksono, Muchammad Ridho Sigit; Qoly, Amelia; Hidayah, Annisaul; Pangestuti, Endah Kanti

    2017-03-01

    Concrete is a mixture of cement, fine aggregate, coarse aggregate and water with or without additives. Concrete can be made with substitution of cement with materials like Fly Ash, CaCO3 and silica sand that can increase the binding on pasta and also increase the compressive strength of concrete. The Superplasticizer on a mixture is used to reduce the high water content, improve concrete durability, low permeability concrete by making it more resilient, and improve the quality of concrete. The combination between Fly Ash (30% of cement required), CaCO3 (10% of cement required) and silica sand (5% of cement required) with added MasterGlenium ACE 8595 as much as 1,2% from total cement will produces compressive strength of up to 1080 kN/cm2 or 73,34 Mpa when the concrete is aged at 28 day. By using this technique and innovation, it proves that the cost reduction is calculated at 27%, which is much more efficient. While the strength of the concrete is increased at 5% compared with normal mixture.

  13. Reductive smelting of spent lead-acid battery colloid sludge in a molten Na2CO3 salt

    Institute of Scientific and Technical Information of China (English)

    Yu-jie Hu; Chao-bo Tang; Mo-tang Tang; Yong-ming Chen

    2015-01-01

    Lead extraction from spent lead–acid battery paste in a molten Na2CO3 salt containing ZnO as a sulfur-fixing agent was studied. Some influencing factors, including smelting temperature, reaction time, ZnO and salt dosages, were investigated in detail using single-factor experiments. The optimum conditions were determined as follows:T = 880°C;t = 60 min; Na2CO3/paste mass ratio = 2.8:1; and the ZnO dosage is equal to the stoichiometric requirement. Under the optimum conditions, the direct recovery rate of lead reached 98.14%. The re-sults suggested that increases in temperature and salt dosage improved the direct recovery rate of lead. XRD results and thermodynamic cal-culations indicated that the reaction approaches of lead and sulfur were PbSO4→Pb and PbSO4→ZnS, respectively. Sulfur was fixed in the form of ZnS, whereas the molten salt did not react with other components, serving only as a reaction medium.

  14. Density functional theory study on the magnetic properties of Co3O4 with normal spinel structure

    Science.gov (United States)

    Lima, A. F.

    2016-04-01

    The magnetic properties of Co3O4 with a normal spinel structure were investigated via the full potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT). The exchange and correlation effects between electrons were treated with a standard generalized gradient approximation (GGA) from Perdew-Burke-Ernzerhof (PBE), as a function of the on-site Coulomb U term, the GGA-PBE+U method, and a B3PW91 hybrid functional with different Hartree-Fock exchange admixtures. Were calculated all of these exchange-correlation (XC) functionals both with and without spin-orbit coupling (SOC). The objective for these calculations was to predict the ground-state magnetic structure of Co3O4 crystal using different XC functionals and to investigate the influence that SOC had on these results. All of our calculations confirmed that the collinear antiferromagnetic (AFM) order was energetically more favorable than the ferromagnetic (FM) one, which agrees with experimental findings. This conclusion was not influenced by the XC functional type employed or whether the spin-orbit effect was used. Thus, the present work does not confirm the recent DFT plane wave pseudopotential results that when including spin-orbit effects, the calculations determined that the collinear FM state had lower energy than the AFM one.

  15. Phototrophic Growth and Accumulation of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate by Purple Nonsulfur Bacterium Rhodopseudomonas palustris SP5212

    Directory of Open Access Journals (Sweden)

    M. Mukhopadhyay

    2013-01-01

    Full Text Available The ability of the phototrophic bacterium Rhodopseudomonas palustris SP5212 to produce polyhydroxyalkanoates (PHAs, poly(3-hydroxybutyrate-co-3-hydroxyvalerate [P(3HB-co-3HV] in particular was, assessed in acetate medium supplemented with hydroxybutyrate and valerate as cosubstrates. The isolate accumulated the polymer accounting for some 49.06% and 30% of cell dry weight when grown in hydroxybutyrate and valerate, respectively. PHA accumulation as well as 3HV monomer incorporation (30 mol% was maximum at 0.1% hydroxybutyrate, while valerate at 0.1% and 0.3% was suitable for total polymer accumulation and 3HV monomer incorporation, respectively. Cosupplementation of hydroxybutyrate and valerate in the ratio of 3 : 1 led to the accumulation of PHA accounting for 54% of cell dry weight, which contained more than 50 mol% of 3HV monomer. Moreover, the biphasic cultivation conditions with hydroxybutyrate as cosubstrate have improved the quality as well as quantity of the accumulated copolymer significantly.

  16. Co3+-modified Surface of LiMn2O4 Spinel for its Improvement of Electrochemical Properties

    Institute of Scientific and Technical Information of China (English)

    Zishan ZHENG; Zilong TANG; Zhongtai ZHANG; Junbiao LU; Wanci SHEN

    2003-01-01

    Cobalt was used to modify the surface of spinel LiMn2O4 by a solution technique to produce Co3+-modified surface material (COMSM). Cobalt was only doped into the surface of LiMn2O4 spinel. XPS(X-ray photoelectron spectroscopy) analysis confirms the valence state of Co3+. COMSM has stable spinel structure and can prevent active materials from the corrosion of electrolyte. The ICP(inductively coupled plasma) determination of the spinel dissolution in electrolyte showed the content of Mn dissolved from COMSM was smaller than that from the pure spinel. AC impedance patterns show that the charge-transfer resistance (Rct) for COMSM is smaller than that for pure spinel. The particles of COMSM are bigger in size than those of pure spinel according to the micrographs of SEM(scanning electron microscopy). The determinations of the electrochemical characterization show that COMSM has both good cycling performance and high initial capacity of 124.1 mA/h at an average capacity loss of 0.19 mAh/g per cycle.

  17. Physiological and Proteomic Analysis of NaCl and Na2CO3 Tolerance in Puccinellia tenuiflora

    Institute of Scientific and Technical Information of China (English)

    Shaojun Dai; Zepeng Yin; Jinwei Suo

    2012-01-01

    Soil salinity poses a serious threat to agriculture productivity throughout the world.Studying mechanisms of salinity tolerance in halophytic plants will provide valuable information for engineering plants for enhanced salt tolerance.Monocotyledonous Puccinellia tenuiflora is a halophytic species that widely distributed in the saline-alkali soil of the Songnen plain in northeastern China.Here we investigate the molecular mechanisms underlying moderate NaCl and Na2CO3 tolerance in leaves and root of P.tenuiflora using a combined physiological and proteomic approach.Our results implied some specific mechanisms in leaves of NaCI-stressed seedlings.They are (1) reduction of photosynthesis under salt treatment attributed to the decrease of the abundance of light-harvesting complex and Calvin cycle enzymes;(2) selective uptake of inorganic ions reflecting from high K+/Na+ ratio,Ca2+ concentration changes; (3) accumulation of osmoly-tes contributed to ion balance and osmotic adjustment in leaf cells; (4) diverse reactive oxygen species (ROS) scavenging mechanisms including enhancement of the photorespiration pathway and thermal dissipation,synthesis of the low-molecular-weight antioxidant tocopherol.The Na2CO3 responsive mechanism in P.tenuiflora chloroplast was reported using iTRAQ labeling proteomic approach.The results revealed that P.tenuiflora chloroplast may utilize various strategies to cope with Na2CO3 treatment,including (1) reduction of excessive light energy absorption by decreasing chlorophyll content and inhibiting chlorophyll a/b binding protein expression; (2) enhancement of the heat dissipation by increasing photochemical quenching and accelerating xanthophyll cycle,and thereby reduce the damage of photosynthetic apparatus caused by excessive light energy; (3) minimization of the oxidative injury by elevating the specific antioxidant system and enhancing the dissolution of xanthophyll synthetic substrates and intermediate products.In the roots under Na2CO3

  18. Synthesis and Characterization of Nano Co-Mn-Al-CO3 Layered Double Hydroxides%纳米Co-Mn-Al-CO3层状双金属氢氧化物的合成及表征

    Institute of Scientific and Technical Information of China (English)

    段标标; 隋铭皓; 盛力

    2012-01-01

    The nanoparticle Co-Mn-Al-CO3 layered double hydroxides (LDHs) were synthesized by coprecipita-tion method using manganese nitrate as manganese source, cobalt nitrate as cobalt source, alumina nitrate as alumina source, and sodium hydroxide and sodium carbonate alkaline medium. Three kinds of Co-Mn-Al LDHs with various Co : Mn : Al molar ratios(4 : 2 : 0, 4 : 1 : 1, and 4 : 0 : 2) were prepared X-ray diffraction (XRD), X-ray fluore-scence(XRF), N2 adsorption-desorption and transmission electron microscopy (TEM) were used to characterize the synthesized samples. It's observed that with the increase of Mn/Al molar ratio, the degree of crystallinity, ordered morphologies and average pore diameter decreased, while the specific surface area and the pore volume of Co-Mn-Al-CO3 increased.%以过渡金属盐Co(NO3)2、Mn(NC3)2为钴源、锰源,Al(NC3)3为铝源,NaOH和Na2CO3混合溶液为碱性介质,利用共沉淀法分别制备了n(Co)∶n(Mn)∶n(Al)=4∶0∶2、4∶1∶1、4∶2∶0的CO32-离子插层纳米层状双金属氢氧化物(LDHs).利用X射线衍射(XRD)、X射线荧光光谱分析(XRF)、N2吸附脱附、透射电镜(TEM)技术对样品进行了表征.结果表明,样品呈层状片状,随着LDHs样品中Mn、Al原子比的增加,结晶度变差,形貌变得无序,平均孔径减小,比表面积和孔道容量变大.

  19. Modification of calcium carbonate by polyether coupling and the properties of CaCO3/PP material%聚醚偶联剂改性碳酸钙及CaCO3/PP复合材料的性能

    Institute of Scientific and Technical Information of China (English)

    曲燕; 杨大伟; 李乾斌; 程如清; 魏鑫

    2013-01-01

    自制了偶联剂四氢呋喃均聚醚(PTHF),并用其对轻质碳酸钙表面进行处理,将处理后的碳酸钙填充到聚丙烯塑料中,探讨了新型改性剂对复合材料力学性能的影响.结果表明,四氢呋喃均聚醚能够使碳酸钙的吸油值降低到22%,接触角降低到68.6°.改性后的碳酸钙填充进聚丙烯,能在一定程度上缓解拉伸强度的下降趋势,使复合材料的断裂伸长率达到28.47%、冲击强度达到6.7 kJ/m2.SEM观察四氢呋喃均聚醚添加前后复合材料的断面形态,表明碳酸钙在聚丙烯中分散良好.%Homemade agent-tetrahydrofuran polyether (PTHF) was used to treat the surface of the precipitated calcium carbonate.The impacts of surface modified CaCO3 with coupling agent of PTHF on CaCO3/PP mechanical properties of composite material were studied.The result showed that tetrahydrofuran polyether was able to make the oil absorption of calcium carbonate reduced to 22% and the contact angle decreased to 68.6°.CaCO3 with PTHF filling in the polypropylene can also alleviate the downward trend of the tensile strength to a certain extent,making the elongation at break of composites reached 28.47% and the impact strength of the composites reached 6.7 kJ/m2.Calcium carbonate with PTHF dispersed better in polypropylene than calcium carbonate by scanning electron microscopy (SEM).

  20. Thermodynamic analysis of Bi2S3-ZnO-Na2CO3 and its application%Bi2S3-ZnO-Na2CO3体系热力学分析及应用

    Institute of Scientific and Technical Information of China (English)

    刘小文; 杨建广; 李静; 陈永明; 孙亚辉; 唐谟堂

    2012-01-01

    对Bi2S3-ZnO-Na2CO3低温熔盐体系进行热力学分析,计算了在700~1 500 K温度下体系中各反应的标准吉布斯自由能变化值(△GθT),并绘制了相应的△GθT-T图.热力学分析结果表明,在700~1100K温度范围内,Bi2S3中的Bi会被C还原成金属Bi进入金属相中,S将以ZnS形式进入固体物渣中.根据分析结果,在700~1100K温度下,以Na2CO3等钠盐为熔剂、ZnO为固硫剂、粉煤为还原剂,开展了验证试验.试验得到了直收率达98%的粗铋,S几乎100%以ZnS的形式固定在渣中,与热力学分析结果一致.%The thermodynamic analysis of Bi2S3-ZnO-Na2CO3 low temperature molten salt system was carried out. Based on calculating reactions entropy (△GΘT) of this low temperature molten salt system at 700-1 500 K, the relationship between △GΘT and reaction temperature (7) within this temperature range was obtained. The results of thermodynamic analysis show that bismuth in Bi2S3 can be reduced by carbon to metal Bi and then get into the metal phase, and sulfur can be fixed in ZnS and get in solid slag. By using soda and other sodium salt as flux, zinc oxide as sulfur additives, coal or coke powder as reducing agent, two verification experiments were carried out at 700-1 100 K. The verification test results show that crude bismuth can be obtained at this low temperature. Bismuth direct yield is greater than 98%, and all sulfur embraced in raw materials can be fixed as zinc sulfide. The verification test results are in accordance with the thermodynamic analysis results.

  1. AgBr/Ag2CO3异质结光催化剂的制备及其可见光响应活性%Preparation of AgBr/Ag2 CO3 Hybrids Photocatalyst and Its Visible-light-resonsive Photocatalytic Activity

    Institute of Scientific and Technical Information of China (English)

    戴杨叶; 张栌予; 尹玲玲; 陈健; 徐秀泉

    2016-01-01

    以硝酸银、碳酸钠为原料,通过共沉淀法获得Ag2 CO3纳米粒,并以该纳米粒为前体化合物,采用原位离子交换法合成系列AgBr/Ag2 CO3异质结可见光催化剂。采用XRD、 SEM测定了抑制结的组成和形貌。同时考察了该催化剂在可见光下(λ>420 nm)的光催化降解盐酸莫西沙星性能。结果表明AgBr与Ag2 CO3摩尔比为0.6时AgBr/Ag2 CO3有最高的光催化活性, AgBr/Ag2 CO3异质结光催化剂可有效提高Ag2 CO3光催化剂降解盐酸莫西沙星的活性和稳定性。%A series of AgBr/Ag2 CO3 hybrids with visible-light responsive using Ag 2 CO3 via in situ anion-exchange method were obtained.The composites were characterized by means of XRD and SEM .The hybridized composites displayed highest photocatalytic activity for the photodegradation of moxifloxacin hydrochloride pollutant under visible -light irradiation when the composites with the proportion 0.6 of AgBr to Ag2 CO3.AgBr/Ag2 CO3 hybrids can enhance the phtocatalytic activity and stability of Ag 2 CO3 for phtodegradation MX.

  2. Soft-template-synthesis of hollow CuO/Co3O4 composites for pseudo-capacitive electrode: A synergetic effect on electrochemical performance

    Science.gov (United States)

    Wang, Kuaibing; Lv, Bo; Wu, Hua; Luo, Xuefei; Xu, Jiangyan; Geng, Zhirong

    2016-12-01

    Hollow CuO/Co3O4 hybrids, which inherited from its coordination polymer precursor consisting of sheets layer and nanoparticles layer composites, were synthesized and characterized by SEM, EDX, XRD and XPS. To assess its electrochemical capacitive performances, cyclic voltammetry, galvanostatic charging-discharging measurements and A.C. impedance tests were performed successively. The CuO/Co3O4 hybrids had higher capacitance and lower charge transfer resistance than bare Co3O4 nanostructures, revealing that it provided a protection layer and produced a synergistic effect due to the existence of CuO layer. The distinct synergistic effect could be further confirmed by endurance cycling tests. The capacitance of the CuO/Co3O4 hybrids was 111% retained after 500 cycles at a charging rate of 1.0 A g-1 and remained an intense growth trend after 2000 cycles at scan rate of 200 mV s-1.

  3. The Research on Thermal Properties and Hydrophobility of the Native Starch/hydrolysis Starch Blends with Treated CaCO3 Powder

    Science.gov (United States)

    Liu, Chia-I.; Huang, Chi-Yuan

    2008-08-01

    In this research, hydrolysis starch was added into the starch blends to study the thermal properties. The enthalpy of blends had a significant decrease to 109J/g as content of treated CaCO3 increased to 5wt%. The modified starch was degraded slightly to produce glucose in the hydrolysis treatment. The amount of glucose in native starch and hydrolysis starch was 0.09 μmol and 0.14 μmol by the DNS measurement. Moreover, CaCO3 treated with titanium coupling agent was also added to improve miscibility and hydrophobility in the starch blends. The contact angle of the blends increased from 60° to 95° when 15wt% treated CaCO3 was added. Treated CaCO3 was confirmed to improve the hydrophobility of starch blends effectively.

  4. Molecular modeling of the octacoordinated tetracarbonato-Nd(Ⅲ),[Nd(CO3)4]5-,complex and its nonacoordinated fluoro- and aquo-adducts

    Institute of Scientific and Technical Information of China (English)

    S.P.Sinha; M.Simas; L.C.Moura

    2010-01-01

    Theoretical investigation on the structures of the octacoordinated[Nd(CO3)4]5- and the nonacoordinated[Nd(CO3)4·OH2]5- complexes,using the SPARKLE parameters of the lanthanides within MOPAC,revealed that they possessed dodecahedral and square antiprismatic structures respectively with an average Nd-O distance of 0.249 nm.These structures and the Nd-O distances agreed well with those experimentally found in the crystal structures.Replacing the water molecule with a fluoride ion or a mondentatecarbonato ligand resulted in a nonacoordimted distorted square antiprismatic structures where the trans-carbonato groups were twisted.The corresponding decacoordinated structures with two fluoride ions or a bidentatecarbonato group,[Nd(CO3)4·F2]7- and[Nd(CO3)5]7.were also investigated.In both cases considerable twisting of the transcarbonato groups was observed.

  5. 交叉缩放椭圆管CaCO3污垢特性的实验研究%Experimental Investigation on the CaCO3 Fouling Characteristics of the Alternating Elliptical Axis Tube

    Institute of Scientific and Technical Information of China (English)

    张仲彬; 李兴灿; 郭进生; 徐志明

    2011-01-01

    The characteristics of heat transfer and CaCO3 fouling were studied by the method of comparative experiments for the alternating elliptical axis tube and the copper tube in this paper, the flow field and wall shear stress in the alternating elliptical axis tube were numerically simulated and analyzed. The results show that the alternating elliptical axis tube has better heat transfer performance and anti-fouling ability than its corresponding copper tube, the periodic change of flow field and wall shear stress in the alternating elliptical axis tube may be the primary reason. In addition, the alternating elliptical axis tube has greater asymptotic value of fouling resistance at low speed. While the flow velocity increased to a certain value, there is not obvious effect on the asymptotic value of fouling resistance.%采用对比实验的方法对交叉缩放椭圆管与铜光管的传热和CaCO3污垢特性进行了研究,并用数值方法模拟了交叉缩放椭圆管的内部流场和壁面剪切力。实验结果表明:交叉缩放椭圆管的换热和抗垢性能均优于在对应状态下的铜光管,这主要是由于交叉缩放椭圆管的内部流场和壁面剪切力的周期性变化所引起的。交叉缩放椭圆管在低流速时污垢热阻渐近值较大,当流速增大到一定程度后,再提高流速对污垢热阻渐近值的影响不明显。

  6. Surface-Tuned Co3O4 Nanoparticles Dispersed on Nitrogen-Doped Graphene as an Efficient Cathode Electrocatalyst for Mechanical Rechargeable Zinc-Air Battery Application.

    Science.gov (United States)

    Singh, Santosh K; Dhavale, Vishal M; Kurungot, Sreekumar

    2015-09-30

    The most vital component of the fuel cells and metal-air batteries is the electrocatalyst, which can facilitate the oxygen reduction reaction (ORR) at a significantly reduced overpotential. The present work deals with the development of surface-tuned cobalt oxide (Co3O4) nanoparticles dispersed on nitrogen-doped graphene as a potential ORR electrocatalyst possessing some unique advantages. The thermally reduced nitrogen-doped graphene (NGr) was decorated with three different morphologies of Co3O4 nanoparticles, viz., cubic, blunt edged cubic, and spherical, by using a simple hydrothermal method. We found that the spherical Co3O4 nanoparticle supported NGr catalyst (Co3O4-SP/NGr-24h) has acquired a significant activity makeover to display the ORR activity closely matching with the state-of-the-art Pt supported carbon (PtC) catalyst in alkaline medium. Subsequently, the Co3O4-SP/NGr-24h catalyst has been utilized as the air electrode in a Zn-air battery, which was found to show comparable performance to the system derived from PtC. Co3O4-SP/NGr-24h catalyst has shown several hours of flat discharge profile at the discharge rates of 10, 20, and 50 mA/cm(2) with a specific capacity and energy density of ~590 mAh/g-Zn and ~840 Wh/kg-Zn, respectively, in the primary Zn-air battery system. In conjunction, Co3O4-SP/NGr-24h has outperformed as an air electrode in mechanical rechargeable Zn-air battery as well, which has shown consistent flat discharge profile with minimal voltage loss at a discharge rate of 50 mA/cm(2). The present results, thus demonstrate that the proper combination of the tuned morphology of Co3O4 with NGr will be a promising and inexpensive material for efficient and ecofriendly cathodes for Zn-air batteries.

  7. Comparison of CaCO3 from Natural Sources and Artificial Carbonates as Activators of Solid-Phase Carburizing of Low-Carbon Steel

    Science.gov (United States)

    González-Angeles, A.; López-Cuevas, J.; Pitalúa-Díaz, N.

    2013-11-01

    The process of solid-phase carburizing of steel with the use of carbonates of different origin including chemical reagents, limestone and oyster shells is studied. The highest microhardness is obtained in the case of SrCO3, wheres Na2CO3 is shown to be the cheapest and most economically expedient carbonate. A good carburized layer can be obtained using a mixture of limestone and oyster shells.

  8. Co3O4 nanoparticles anchored on nitrogen-doped reduced graphene oxide as a multifunctional catalyst for H2O2 reduction, oxygen reduction and evolution reaction

    Science.gov (United States)

    Zhang, Tingting; He, Chuansheng; Sun, Fengzhan; Ding, Yongqi; Wang, Manchao; Peng, Lin; Wang, Jiahui; Lin, Yuqing

    2017-01-01

    This study describes a facile and effective route to synthesize hybrid material consisting of Co3O4 nanoparticles anchored on nitrogen-doped reduced graphene oxide (Co3O4/N-rGO) as a high-performance tri-functional catalyst for oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and H2O2 sensing. Electrocatalytic activity of Co3O4/N-rGO to hydrogen peroxide reduction was tested by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometry. Under a reduction potential at −0.6 V to H2O2, this constructing H2O2 sensor exhibits a linear response ranging from 0.2 to 17.5 mM with a detection limit to be 0.1 mM. Although Co3O4/rGO or nitrogen-doped reduced graphene oxide (N-rGO) alone has little catalytic activity, the Co3O4/N-rGO exhibits high ORR activity. The Co3O4/N-rGO hybrid demonstrates satisfied catalytic activity with ORR peak potential to be −0.26 V (vs. Ag/AgCl) and the number of electron transfer number is 3.4, but superior stability to Pt/C in alkaline solutions. The same hybrid is also highly active for OER with the onset potential, current density and Tafel slope to be better than Pt/C. The unusual catalytic activity of Co3O4/N-rGO for hydrogen peroxide reduction, ORR and OER may be ascribed to synergetic chemical coupling effects between Co3O4, nitrogen and graphene. PMID:28272415

  9. Co3O4 nanoparticles anchored on nitrogen-doped reduced graphene oxide as a multifunctional catalyst for H2O2 reduction, oxygen reduction and evolution reaction

    Science.gov (United States)

    Zhang, Tingting; He, Chuansheng; Sun, Fengzhan; Ding, Yongqi; Wang, Manchao; Peng, Lin; Wang, Jiahui; Lin, Yuqing

    2017-03-01

    This study describes a facile and effective route to synthesize hybrid material consisting of Co3O4 nanoparticles anchored on nitrogen-doped reduced graphene oxide (Co3O4/N-rGO) as a high-performance tri-functional catalyst for oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and H2O2 sensing. Electrocatalytic activity of Co3O4/N-rGO to hydrogen peroxide reduction was tested by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometry. Under a reduction potential at ‑0.6 V to H2O2, this constructing H2O2 sensor exhibits a linear response ranging from 0.2 to 17.5 mM with a detection limit to be 0.1 mM. Although Co3O4/rGO or nitrogen-doped reduced graphene oxide (N-rGO) alone has little catalytic activity, the Co3O4/N-rGO exhibits high ORR activity. The Co3O4/N-rGO hybrid demonstrates satisfied catalytic activity with ORR peak potential to be ‑0.26 V (vs. Ag/AgCl) and the number of electron transfer number is 3.4, but superior stability to Pt/C in alkaline solutions. The same hybrid is also highly active for OER with the onset potential, current density and Tafel slope to be better than Pt/C. The unusual catalytic activity of Co3O4/N-rGO for hydrogen peroxide reduction, ORR and OER may be ascribed to synergetic chemical coupling effects between Co3O4, nitrogen and graphene.

  10. Stable solid and aqueous H2CO3 from CO2 and H2O at high pressure and high temperature

    Science.gov (United States)

    Wang, Hongbo; Zeuschner, Janek; Eremets, Mikhail; Troyan, Ivan; Willams, Jonathan

    2016-01-01

    Carbonic acid (H2CO3) forms in small amounts when CO2 dissolves in H2O, yet decomposes rapidly under ambient conditions of temperature and pressure. Despite its fleeting existence, H2CO3 plays an important role in the global carbon cycle and in biological carbonate-containing systems. The short lifetime in water and presumed low concentration under all terrestrial conditions has stifled study of this fundamental species. Here, we have examined CO2/H2O mixtures under conditions of high pressure and high temperature to explore the potential for reaction to H2CO3 inside celestial bodies. We present a novel method to prepare solid H2CO3 by heating CO2/H2O mixtures at high pressure with a CO2 laser. Furthermore, we found that, contrary to present understanding, neutral H2CO3 is a significant component in aqueous CO2 solutions above 2.4 GPa and 110 °C as identified by IR-absorption and Raman spectroscopy. This is highly significant for speciation of deep C-O-H fluids with potential consequences for fluid-carbonate-bearing rock interactions. As conditions inside subduction zones on Earth appear to be most favorable for production of aqueous H2CO3, a role in subduction related phenomena is inferred.

  11. Structural evaluation and nonlinear optical properties of Ni/NiO, Ni/NiCo2O4 and Co/Co3O4 nanocomposites

    Science.gov (United States)

    Rahulan, K. Mani; Padmanathan, N.; Philip, Reji; Balamurugan, S.; Kanakam, Charles C.

    2013-10-01

    Nanocomposites of Ni/NiO, Ni/NiCo2O4 and Co/Co3O4 have been synthesized by a chemical reduction technique. X-ray diffraction (XRD) and transmission electron microscopy (TEM) images confirm the mixed composite nature of the sample and uniform particle size of approximately 13 nm. Formation of Ni/NiCo3O4 solid solution or NiCo2O4 spinel phase in the mixed composite is confirmed by energy dispersive X-ray (EDX) spectrum. Magnetic hysteresis (M-H) curves of the nanocomposites show excellent ferromagnetic (FM) nature at room temperature. Nonlinear optical transmission of the nanocomposites is measured using the open aperture Z-scan technique employing 7 nanosecond laser pulses at 532 nm. Experimental results show that NiO/NiO-Co3O4/Co3O4 nanocomposites exhibit good optical limiting performance. From the measurements and numerical fitting of the data to theory, it is found that nonlinear absorption has contributions from excited state absorption and two-photon absorption. Optical limiting is enhanced in Co3O4 and Ni/NiCo2O4 in which the Co3O4 content has a larger volume ratio.

  12. Synthesis of gadolinium carbonate-conjugated-poly(ethylene)glycol (Gd2(CO3)3@PEG) particles via a modified solvothermal method

    Science.gov (United States)

    Nasution, Erika L. Y.; Ahab, Atika; Nuryadin, Bebeh W.; Haryanto, Freddy; Arif, Idam; Iskandar, Ferry

    2016-02-01

    PEGylated gadolinium carbonate ((Gd2(CO3)3)@PEG) powder was successfully synthesized by a modified solvothermal method. The synthesized products were characterized by means of X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDS). A systematic change in the chemical surface composition, crystallinity and size properties of the Gd2(CO3)3@PEG particles was observed by increasing the reaction time at 5 hours, 7 hours, and 8 hours. The corresponding XRD patterns showed that the Gd2(CO3)3 particles had hexagonal symmetry (JCPDS No. 37-0559) with a crystallite size of 3.5, 2.9, and 4.6 nm. FTIR spectra showed that the Gd2(CO3)3)@PEG particles were formed with the PEG as carbonyl and hydroxyl group attached to the surface. SEM analysis showed that the Gd2(CO3)3)@PEG particles had a flake-like morphology of homogeneous sized particles and agglomerates. EDS analysis confirmed the presence of constituent Gd2(CO3)3 elements.

  13. WO3 Nanoparticles or Nanorods Incorporating Cs2CO3/PCBM Buffer Bilayer as Carriers Transporting Materials for Perovskite Solar Cells

    Science.gov (United States)

    Chen, Chih-Ming; Lin, Zheng-Kun; Huang, Wei-Jie; Yang, Sheng-Hsiung

    2016-10-01

    In this work, we demonstrate a novel carrier transporting combination made of tungsten trioxide (WO3) nanomaterials and Cs2CO3/PCBM buffer bilayer for the fabrication of perovskite solar cells (PSCs). Two different types of WO3, including nanoparticles and nanorods, were prepared by sol-gel process and hydrothermal method, respectively. Cs2CO3/PCBM buffer bilayer was inserted between WO3 and perovskite layers to improve charge transfer efficiency and formation of pinhole-free perovskite layer. Besides, the leakage current of the devices containing Cs2CO3/PCBM buffer bilayer was significantly suppressed. The optimized device based on WO3 nanoparticles and Cs2CO3/PCBM bilayer showed an open-circuit voltage of 0.84 V, a short-circuit current density of 20.40 mA/cm2, a fill factor of 0.61, and a power conversion efficiency of 10.49 %, which were significantly higher than those of PSCs without Cs2CO3/PCBM buffer bilayer. The results revealed that the combination of WO3 nanomaterials and Cs2CO3/PCBM bilayer provides an effective solution for improving performances of PSCs.

  14. Co3O4 nanoparticle-modified MnO2 nanotube bifunctional oxygen cathode catalysts for rechargeable zinc-air batteries

    Science.gov (United States)

    Du, Guojun; Liu, Xiaogang; Zong, Yun; Hor, T. S. Andy; Yu, Aishui; Liu, Zhaolin

    2013-05-01

    We report the preparation of MnO2 nanotubes functionalized with Co3O4 nanoparticles and their use as bifunctional air cathode catalysts for oxygen reduction reaction and oxygen evolution reaction in rechargeable zinc-air batteries. These hybrid MnO2/Co3O4 nanomaterials exhibit enhanced catalytic reactivity toward oxygen evolution reaction under alkaline conditions compared with that in the presence of MnO2 nanotubes or Co3O4 nanoparticles alone.We report the preparation of MnO2 nanotubes functionalized with Co3O4 nanoparticles and their use as bifunctional air cathode catalysts for oxygen reduction reaction and oxygen evolution reaction in rechargeable zinc-air batteries. These hybrid MnO2/Co3O4 nanomaterials exhibit enhanced catalytic reactivity toward oxygen evolution reaction under alkaline conditions compared with that in the presence of MnO2 nanotubes or Co3O4 nanoparticles alone. Electronic supplementary information (ESI) available: Zinc-air cell device, XPS survey scan and power density of the cell. See DOI: 10.1039/c3nr00300k

  15. Ab Initio Thermodynamic Study of the CO2 Capture Properties of Potassium Carbonate Sesquihydrate, K2CO3·1.5H2O

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Yuhua; Luebkes,David R.; Pennline, Henry W; Li, Bingyun Li; Janik, Michael J.; Halley, Woods

    2012-01-01

    By combining density functional theory and lattice phonon dynamics, the thermodynamic properties of CO2 absorption/desorption reactions with dehydrated potassium carbonates through K2CO3·1.5H2O + CO2 = 2KHCO3 + 0.5H2O(g) are analyzed. The energy change and the chemical potential of this reaction have been calculated and used to evaluate its thermodynamic properties and phase transitions. The results indicate that the K2CO3·1.5H2O can only be applied for postcombustion CO2 capture technology at temperatures lower than its phase transition temperature, which depends on the CO2 pressure and the steam pressure with the best range being PH2O ≤ 1.0 bar. Above the phase transition temperature, the sorbent will be regenerated into anhydrous K2CO3. If the steam pressure PH2O is much greater than 1.0 bar, it is possible to use the K2CO3·1.5H2O sorbent for precombustion CO2 capture technology. Compared to anhydrous K2CO3, K2CO3·1.5H2O requires less energy for regeneration.

  16. S2- behaviors analysis in leaching SrS and precipitating high purity SrCO3 by reduction-decomposition process

    Institute of Scientific and Technical Information of China (English)

    彭晓东; 刘相果; 谢卫东; 刘江; 贾上远; 权燕燕

    2004-01-01

    A new preparation method (reduction-decomposition process) for high purity SrCO3 was investigated,which mainly includes four processes: reduction, leaching, purification and precipitation. The affecting factors about S2- behaviors in leaching process and the effects of variables on purity and particle sizes distribution of SrCO3 were analyzed theoretically and practically. It is concluded that with the increase of temperature or decrease of pH value in leaching process, the strontium recovery increases, but SrS decomposes and hydrogen sulphide (H2S) gasdischarges. The purity of SrCO3 is dependent on dissolution-recrystallization times, for example, the purity of SrCO3 is as high as 99.97% when it is recrystallized three times. Besides, the solution concentration of Sr(OH)2and flow rate of CO2 have important effects on particle size distribution of SrCO3 particles, especially, the particle sizes of SrCO3 meanly distribute in 0.1 - 1.0μm when the flow rate of CO2 is about 2 000 mL/min and other parameters are invariable.

  17. Synthesis of BaTiO3 nanoparticles from TiO2-coated BaCO3 particles derived using a wet-chemical method

    Directory of Open Access Journals (Sweden)

    Yuuki Mochizuki

    2014-03-01

    Full Text Available BaCO3 particles coated with amorphous TiO2 precursor are prepared by a wet chemical method to produce BaTiO3 nanoparticles at low temperatures. Subsequently, we investigate the formation behavior of BaTiO3 particles and the particle growth behavior when the precursor is subjected to heat treatment. The state of the amorphous TiO2 coating on the surface of BaCO3 particles depends on the concentration of NH4HCO3, and the optimum concentration is found to be in the range 0.5–1.0 M. Thermogravimetric curves of the BaCO3 particles coated with the TiO2 precursor, prepared from BaCO3 particles of various sizes, show BaTiO3 formation occurring mainly at 550–650 °C in the case of fine BaCO3 particles. However, as evidenced from the curves, the temperature of formation of BaTiO3 shifts to higher values with an increase in the size of the BaCO3 particles. The average particle size of single phase BaTiO3 at heat-treatment temperature of 650–900 °C is observed to be in the range 60–250 nm.

  18. Stable solid and aqueous H2CO3 from CO2 and H2O at high pressure and high temperature.

    Science.gov (United States)

    Wang, Hongbo; Zeuschner, Janek; Eremets, Mikhail; Troyan, Ivan; Willams, Jonathan

    2016-01-27

    Carbonic acid (H2CO3) forms in small amounts when CO2 dissolves in H2O, yet decomposes rapidly under ambient conditions of temperature and pressure. Despite its fleeting existence, H2CO3 plays an important role in the global carbon cycle and in biological carbonate-containing systems. The short lifetime in water and presumed low concentration under all terrestrial conditions has stifled study of this fundamental species. Here, we have examined CO2/H2O mixtures under conditions of high pressure and high temperature to explore the potential for reaction to H2CO3 inside celestial bodies. We present a novel method to prepare solid H2CO3 by heating CO2/H2O mixtures at high pressure with a CO2 laser. Furthermore, we found that, contrary to present understanding, neutral H2CO3 is a significant component in aqueous CO2 solutions above 2.4 GPa and 110 °C as identified by IR-absorption and Raman spectroscopy. This is highly significant for speciation of deep C-O-H fluids with potential consequences for fluid-carbonate-bearing rock interactions. As conditions inside subduction zones on Earth appear to be most favorable for production of aqueous H2CO3, a role in subduction related phenomena is inferred.

  19. The urchin-like sphere arrays Co3O4 as a bifunctional catalyst for hydrogen evolution reaction and oxygen evolution reaction

    Science.gov (United States)

    Li, Ruchun; Zhou, Dan; Luo, Jiaxian; Xu, Weiming; Li, Jingwei; Li, Shuoshuo; Cheng, Pengpeng; Yuan, Dingsheng

    2017-02-01

    Electrochemical water splitting has attracted great interest because of the growing demand for sustainable energy and increasing concerns for the environment. We present a facile strategy to design the three-dimensional (3D) urchin-like sphere arrays Co3O4 as an effective bifunctional catalyst for electrochemical water splitting. The 3D urchin-like Co3O4 was directly grown on Ni foam by a hydrothermal reaction and annealing treatment at a low temperature. This process offers several advantages including facile synthesis, binder-free, and low cost. The 3D urchin-like Co3O4 as a catalyst for hydrogen evolution reaction exhibits a low onset potential (-130 mV vs. RHE) and good cycling stability in an alkaline electrolyte. When urchin-like Co3O4 is used as a catalyst for oxygen evolution reaction, the onset potential is at 1.46 V (vs. RHE) with a low overpotential of only 230 mV. The good catalytic activity can be attributed to the unique urchin-like nanostructure, abundant mesopores, and low charge-transfer resistance (compared with Co3O4 NPs). In addition, H2 and O2 generation was performed using Co3O4 as both cathode and anode catalysts with a potential of 1.64 V to reach a current density of 10 mA cm-2.

  20. Biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and characterisation of its blend with oil palm empty fruit bunch fibers.

    Science.gov (United States)

    Salim, Yoga Sugama; Abdullah, Amirul Al-Ashraf; Nasri, Coswald Stephen Sipaut Mohd; Ibrahim, Mohamad Nasir Mohamad

    2011-02-01

    Poly(3-hydroxybutyrate-co-38 mol%-3-hydroxyvalerate) [P(3HB-co-38mol%-3HV)] was produced by Cupriavidus sp. USMAA2-4 in the presence of oleic acid and 1-pentanol. Due to enormous production of empty fruit bunch (EFB) in the oil palm plantation and high production cost of P(3HB-co-3HV), oil palm EFB fibers were used for biocomposites preparation. In this study, maleic anhydride (MA) and benzoyl peroxide (DBPO) were used to improve the miscibility between P(3HB-co-3HV) and EFB fibers. Introduction of MA into P(3HB-co-3HV) backbone reduced the molecular weight and improved the thermal stability of P(3HB-co-3HV). Thermal stability of P(3HB-co-3HV)/EFB composites was shown to be comparable to that of commercial packaging product. Composites with 35% EFB fibers content have the highest tensile strength compared to 30% and 40%. P(3HB-co-3HV)/EFB blends showed less chemicals leached compared to commercial packaging.

  1. Preferential Oxidation of Carbon Monoxide in Excess Hydrogen over Au/Co3O4- CeO2 Catalysts

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Au/Co3O4-CeO2 mixed-oxide catalysts were shown experimentally to be highly active and selective for the oxidation of CO in hydrogen-rich mixture. Activity was markedly influenced by the composition of the support, aging temperature and Au-loading temperature. It provided that single-step removal of CO from hydrogen-rich stream both in the absence and presence of CO2 and H2O to a PEMFC tolerant level. It was found that catalytic activity is greatly affected by adding CO2 in the mixture and increased by farther adding H2O. It meants H2O has the effect to rise catalytic activity. Moreover,it shows better stability with reaction time for the preferential CO oxidation.

  2. Quadratic susceptibility and first hyperpolarizability of the complex of Cr(CO)3 with [2.2]paracyclophane

    Science.gov (United States)

    Suponitsky, Kyrill Yu.; Antonov, Dmitrii; Puntus, Lada N.; Smol'yakov, Alexander F.; Kajzar, Francois; Rau, Ileana; Sahraoui, Bouchta; Lyssenko, Konstantin A.

    2013-11-01

    The peculiarities of chemical bonding and nonlinear optical properties of the complex of Cr(CO)3 with [2.2]paracyclophane (Cr-pCp) have been studied by a combined experimental-theoretical approach. The Cr-pCp complex exhibits second harmonic generation, the efficiency of which was measured by the powder technique at 1064.2 nm fundamental wavelength and estimated theoretically. The comparison of electronic structure of the Cr-pCp with benzene tricarbonyl chromium analogue has revealed an important role of intraligand charge transfer state in pCp moiety conditioned by a strong transannular interaction between aromatic rings which is responsible for the enhanced molecular hyperpolarizability of Cr-pCp.

  3. Preparation and characterization of activated carbon from sunflower seed oil residue via microwave assisted K2CO3 activation.

    Science.gov (United States)

    Foo, K Y; Hameed, B H

    2011-10-01

    Sunflower seed oil residue, a by-product of sunflower seed oil refining, was utilized as a feedstock for preparation of activated carbon (SSHAC) via microwave induced K(2)CO(3) chemical activation. SSHAC was characterized by Fourier transform infrared spectroscopy, nitrogen adsorption-desorption and elemental analysis. Surface acidity/basicity was examined with acid-base titration, while the adsorptive properties of SSHAC were quantified using methylene blue (MB) and acid blue 15 (AB). The monolayer adsorption capacities of MB and AB were 473.44 and 430.37 mg/g, while the Brunauer-Emmett-Teller surface area, Langmuir surface area and total pore volume were 1411.55 m(2)/g, 2137.72 m(2)/g and 0.836 cm(3)/g, respectively. The findings revealed the potential to prepare high surface area activated carbon from sunflower seed oil residue by microwave irradiation.

  4. Assesment of (Mn,Co)3O4 powders for possible coating material for SOFC/SOEC interconnects

    DEFF Research Database (Denmark)

    Szymczewska, D.; Molin, Sebastian; Venkatachalam, Vinothini

    2015-01-01

    In this work (Mn,Co)3O4 spinel powders with different Mn:Co ratio (1:1 and 1:2) and from different commercial suppliers are evaluated for possible powder for production of interconnect coatings. Sinterability of the powders is evaluated on pressed pellets sintered in oxidizing and in reducing....../oxidizing atmospheres. For selected powder, coatings are then prepared by the electrophoretic deposition method on Crofer 22 APU stainless steel coupons. Effects of dispersant/iodine content and deposition voltage and times are evaluated. Thickness as a function of deposition parameters is described. Results show...... that with appropriate powder it is possible to produce adherent protective coating with a well-controlled thickness....

  5. Magnetization switching behavior with competing anisotropies in epitaxial Co3FeN /MnN exchange-coupled bilayers

    Science.gov (United States)

    Hajiri, T.; Yoshida, T.; Jaiswal, S.; Filianina, M.; Borie, B.; Ando, H.; Asano, H.; Zabel, H.; Kläui, M.

    2016-11-01

    We report unusual magnetization switching processes and angular-dependent exchange bias effects in fully epitaxial Co3FeN /MnN bilayers, where magnetocrystalline anisotropy and exchange coupling compete, probed by longitudinal and transverse magneto-optic Kerr effect (MOKE) magnetometry. The MOKE loops show multistep jumps corresponding to the nucleation and propagation of 90∘ domain walls in as-grown bilayers. By inducing exchange coupling, we confirm changes of the magnetization switching process due to the unidirectional anisotropy field of the exchange coupling. Taking into account the experimentally obtained values of the fourfold magnetocrystalline anisotropy, the unidirectional anisotropy field, the exchange-coupling constant, and the uniaxial anisotropy including its direction, the calculated angular-dependent exchange bias reproduces the experimental results. These results demonstrate the essential role of the competition between magnetocrystalline anisotropy and exchange coupling for understanding and tailoring exchange-coupling phenomena usable for engineering switching in fully epitaxial bilayers made of tailored materials.

  6. Short range ferromagnetic, magneto-electric, and magneto-dielectric effect in ceramic Co3TeO6

    Science.gov (United States)

    Singh, Harishchandra; Ghosh, Haranath; Chandrasekhar Rao, T. V.; Sharma, G.; Saha, J.; Patnaik, S.

    2016-01-01

    We report observation of magneto-electric and magneto-dielectric couplings along with short range ferromagnetic order in ceramic Cobalt Tellurate (Co3TeO6, CTO) using magnetic, structural, dielectric, pyroelectric, and polarization studies. DC magnetization along with dielectric constant measurements indicate a coupling between magnetic order and electrical polarization. A strong anomaly in the dielectric constant at ˜17.4 K in zero magnetic field indicates spontaneous electric polarization, consistent with a recent neutron diffraction study. Observation of weak short range ferromagnetic order at lower temperatures is attributed to the Griffiths-like ferromagnetism. Furthermore, magnetic field dependence of the ferroelectric transition follows earlier theoretical predictions, applicable to single crystal CTO. Finally, combined dielectric, pyroelectric, and polarization measurements suggest that the ground state of CTO may possess spontaneous symmetry breaking in the absence of magnetic field.

  7. Cs2CO3-promoted polycondensation of CO2with diols and dihalides for the synthesis of miscellaneous polycarbonates

    KAUST Repository

    Chen, Zuliang

    2016-07-12

    A one-pot protocol for the direct synthesis of polycarbonates through polycondensation of diols, dihalides and CO2 in the presence of Cs2CO3 is described. The conditions were optimized by studying the polycondensation of CO2 with 1,4-phenylenedimethanol and 1,4-dibromobutane as model monomers. Then, diols and dihalides with different spacers between the reactive groups including aliphatic, aromatic and poly(ethylene glycol) were tested under optimal conditions. Miscellaneous polycarbonates exhibiting molar masses in the range of 43 000 g mol-1 (GPC) and conversion higher than 96% could be obtained. The proposed mechanism rules out the possibility of ether linkage formation during polycondensation and accounts for the creation of carbonate linkages in two different ways. The thermal properties of the synthesized polycarbonates were unveiled by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). © 2016 The Royal Society of Chemistry.

  8. [Development and preclinical studies of insulating membranes based on poly-3-hydroxybutyrate-co-3-hydroxyvalerate for guided bone regeneration].

    Science.gov (United States)

    Ivanov, S Yu; Bonartsev, A P; Gazhva, Yu V; Zharkova, I I; Mukhametshin, R F; Mahina, T K; Myshkina, V L; Bonartseva, G A; Voinova, V V; Andreeva, N V; Akulina, E A; Kharitonova, E S; Shaitan, K V; Muraev, A A

    2015-01-01

    Bone tissue damages are one of the dominant causes of temporary disability and developmental disability. Currently, there are some methods of guided bone regeneration employing different osteoplastic materials and insulation membranes used in surgery. In this study, we have developed a method of preparation of porous membranes from the biopolymer poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV), produced by a strain of Azotobacter chroococcum 7B. The biocompatibility of the porous membranes was investigated in vitro using mesenchymal stem cells (MSCs) and in vivo on laboratory animals. The cytotoxicity test showed the possibility of cell attachment on membrane and histological studies confirmed good insulating properties the material. The data obtained demonstrate the high biocompatibility and the potential application of insulating membranes based on PHBV in bone tissue engineering.

  9. Highly Dispersed Polyoxometalate-Doped Porous Co3 O4 Water Oxidation Photocatalysts Derived from POM@MOF Crystalline Materials.

    Science.gov (United States)

    Lan, Qing; Zhang, Zhi-Ming; Qin, Chao; Wang, Xin-Long; Li, Yang-Guang; Tan, Hua-Qiao; Wang, En-Bo

    2016-10-17

    Rational design of earth-abundant photocatalysts is an important issue for solar energy conversion and storage. Polyoxometalate (POM)@Co3 O4 composites doped with highly dispersive molecular metal-oxo clusters, synthesized by loading a single Keggin-type POM cluster into each confined space of a metal-organic framework (MOF), exhibit significantly improved photocatalytic activity in water oxidation compared to the pure MOF-derived nanostructure. The systematic synthesis of these composite nanocrystals allows the conditions to be tuned, and their respective water oxidation catalytic performance can be efficiently adjusted by varying the thermal treatment temperature and the feeding amount of the POM. This work not only provides a modular and tunable synthetic strategy for preparing molecular cluster@TM oxide (TM=transition metal) nanostructures, but also showcases a universal strategy that is applicable to design and construct multifunctional nanoporous metal oxide composite materials.

  10. Spectroscopic characterisation of the LDH mineral quintinite Mg4Al2(OH)12CO3·3H2O.

    Science.gov (United States)

    Theiss, Frederick; López, Andrés; Frost, Ray L; Scholz, Ricardo

    2015-11-05

    Raman and infrared spectroscopy coupled with scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) have been applied to study the natural hydrotalcite quintinite Mg4Al2(OH)12[CO3]·3H2O. SEM shows the mineral to be a homogenous phase. Quintinite is composed of Mg and Al as the major elements with minor amounts of Fe. Two Raman bands at 1046 and 1062 cm are assigned to the ν1 symmetric stretching modes of the carbonate anion. Thermal treatment shifts these bands to higher wavenumbers indicating a change in the carbonate bonding. Hydrogen bond distances are calculated using a Libowitzky-type empirical function and varied between 2.61 and 3.00 Å. Stronger hydrogen bonds were formed by water units as compared to the hydroxyl units.

  11. Solvent versus temperature control over the infrared band shape and position in Fe(CO)3(η(4)-ligand) complexes.

    Science.gov (United States)

    Giordano, Andrea N; Lear, Benjamin J

    2013-11-27

    The solute-solvent interactions between Fe(CO)3(η(4)-cyclooctatetraene) (FeCOT) and 27 solvents were examined by infrared (IR) spectroscopy. The observed change in band shape and position of the carbonyl bands as a function of solvent was found to be very similar to that previously observed in temperature-dependent IR experiments of Fe(CO)3(η(4)-norborndiene) (FeNBD). While for FeNBD the change in band shape results from dynamic exchange of carbonyl ligands, temperature-dependent IR experiments in ethyl acetate show that the observed changes are not a result of carbonyl ligand site exchange for FeCOT. We therefore concluded that the solvent dependence of the IR spectra must be a consequence of a static solute-solvent interaction. We find that the linear solvation energy model (J. Am. Chem. Soc. 1977, 99, 6027-6038; Chem. Soc. Rev. 1993, 22, 409-416) provides a satisfactory account for the spectral changes due to the solvent. From this model, we are able to conclude that the solute-solvent interactions of this system are influenced by the solvent's polarizability and hydrogen bonding acidity. We also observed interdependence between the change in fwhm and band positions for all three carbonyl bands, which brings us to the conclusion that the observed changes in the IR carbonyl band shape of FeCOT are a consequence of the solute-solvent interactions, rather than any solvent friction effects. This implies that care must be taken to separate the effects of chemical dynamics and solvatochromism when examining IR spectra of molecules suspected of exhibiting dynamically broadened vibrational spectra.

  12. Ultrafast Excited-State Decays in [Re(CO)3(N,N)(L)](n+): Nonadiabatic Quantum Dynamics.

    Science.gov (United States)

    Fumanal, Maria; Gindensperger, Etienne; Daniel, Chantal

    2017-03-14

    The ultrafast luminescent decay of [Re(CO)3(phen)(im)](+), representative of Re(I) carbonyl α-diimine photosensitizers, is investigated by means of wavepacket propagations based on the multiconfiguration time-dependent Hartree (MCTDH) method. On the basis of electronic structure data obtained at the time-dependent density functional theory (TD-DFT) level, the luminescence decay is simulated by solving a 14 electronic states multimode problem including both vibronic and spin-orbit coupling (SOC) up to 15 vibrational modes. A careful analysis of the results provides the key features of the mechanism of the intersystem crossing (ISC) in this complex. The intermediate state, detected by means of fs - ps time-resolved spectroscopies, is assigned to the T3 state corresponding to the triplet intraligand ((3)IL) transition localized on the phen ligand. By switching off/on SOC and vibronic coupling in the model it is shown that efficient population transfer occurs from the optically active metal-to-ligand-charge-transfer1,3MLCT states to T3 and to the lowest long-lived phosphorescent (3)MLCT (T1) state. The early ultrafast SOC-driven decay followed by a T3/T1 equilibration controlled by vibronic coupling underlies the photoluminescent properties of [Re(CO)3(phen)(im)](+). The impact of the axial and N,N ligands on the photophysics of this class of Re(I) complexes is further rationalized on the basis of their calculated optical properties. The relative position of the (3)IL and upper (3)MLCT states with respect to the optically active singlet state is influenced by the N,N ligand and affects the relaxation dynamics.

  13. Physiologic and metagenomic attributes of the rhodoliths forming the largest CaCO3 bed in the South Atlantic Ocean.

    Science.gov (United States)

    Cavalcanti, Giselle S; Gregoracci, Gustavo B; dos Santos, Eidy O; Silveira, Cynthia B; Meirelles, Pedro M; Longo, Leila; Gotoh, Kazuyoshi; Nakamura, Shota; Iida, Tetsuya; Sawabe, Tomoo; Rezende, Carlos E; Francini-Filho, Ronaldo B; Moura, Rodrigo L; Amado-Filho, Gilberto M; Thompson, Fabiano L

    2014-01-01

    Rhodoliths are free-living coralline algae (Rhodophyta, Corallinales) that are ecologically important for the functioning of marine environments. They form extensive beds distributed worldwide, providing a habitat and nursery for benthic organisms and space for fisheries, and are an important source of calcium carbonate. The Abrolhos Bank, off eastern Brazil, harbors the world's largest continuous rhodolith bed (of ∼21,000 km(2)) and has one of the largest marine CaCO3 deposits (producing 25 megatons of CaCO3 per year). Nevertheless, there is a lack of information about the microbial diversity, photosynthetic potential and ecological interactions within the rhodolith holobiont. Herein, we performed an ecophysiologic and metagenomic analysis of the Abrolhos rhodoliths to understand their microbial composition and functional components. Rhodoliths contained a specific microbiome that displayed a significant enrichment in aerobic ammonia-oxidizing betaproteobacteria and dissimilative sulfate-reducing deltaproteobacteria. We also observed a significant contribution of bacterial guilds (that is, photolithoautotrophs, anaerobic heterotrophs, sulfide oxidizers, anoxygenic phototrophs and methanogens) in the rhodolith metagenome, suggested to have important roles in biomineralization. The increased hits in aromatic compounds, fatty acid and secondary metabolism subsystems hint at an important chemically mediated interaction in which a functional job partition among eukaryal, archaeal and bacterial groups allows the rhodolith holobiont to thrive in the global ocean. High rates of photosynthesis were measured for Abrolhos rhodoliths (52.16 μmol carbon m(-2 )s(-1)), allowing the entire Abrolhos rhodolith bed to produce 5.65 × 10(5) tons C per day. This estimate illustrates the great importance of the Abrolhos rhodolith beds for dissolved carbon production in the South Atlantic Ocean.

  14. Study of Gel Growth Cobalt (II Oxalate Crystals as Precursor of Co3O4 Nano Particles

    Directory of Open Access Journals (Sweden)

    Yuniar Ponco Prananto

    2013-03-01

    Full Text Available Crystal growth of cobalt (II oxalate in silica gel at room temperature as precursor of Co3O4 nano particles has been studied. Specifically, this project is focusing on the use of two different reaction tube types toward crystallization of cobalt (II oxalate in gel. The gel was prepared at pH 5 by reacting sodium metasilicate solution with dilute nitric acid (for U-tube and oxalic acid (for straight tube, with gelling time of 4 days and crystal growth time of 8 (for straight tube and 12 (for U-tube weeks. Result shows that pink crystalline powder was directly formed using straight tube method. The use of different solvents in straight tube method affects crystallization and could delay direct precipitation of the product. In contrast, bigger and better shape of red block crystal was yielded from U-tube method; however, longer growth time was needed. FTIR studies suggest that both growth method produces identical compound of hydrated cobalt (II oxalate. © 2013 BCREC UNDIP. All rights reservedReceived: 25th October 2012; Revised: 30th November 2012; Accepted: 5th December 2012[How to Cite: Y.P. Prananto, M.M. Khunur, D.T. Wahyuni, R.A. Shobirin, Y.R. Nata, E. Riskah, (2013. Study of Gel Growth Cobalt (II Oxalate Crystals as Precursor of Co3O4 Nano Particles. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (3: 198-204. (doi:10.9767/bcrec.7.3.4066.198-204][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.7.3.4066.198-204 ] View in  |

  15. Rhodolith beds are major CaCO3 bio-factories in the tropical South West Atlantic.

    Science.gov (United States)

    Amado-Filho, Gilberto M; Moura, Rodrigo L; Bastos, Alex C; Salgado, Leonardo T; Sumida, Paulo Y; Guth, Arthur Z; Francini-Filho, Ronaldo B; Pereira-Filho, Guilherme H; Abrantes, Douglas P; Brasileiro, Poliana S; Bahia, Ricardo G; Leal, Rachel N; Kaufman, Les; Kleypas, Joanie A; Farina, Marcos; Thompson, Fabiano L

    2012-01-01

    Rhodoliths are nodules of non-geniculate coralline algae that occur in shallow waters (Rhodolith beds stand with kelp beds, seagrass meadows, and coralline algal reefs as one of the world's four largest macrophyte-dominated benthic communities. Geographic distribution of rhodolith beds is discontinuous, with large concentrations off Japan, Australia and the Gulf of California, as well as in the Mediterranean, North Atlantic, eastern Caribbean and Brazil. Although there are major gaps in terms of seabed habitat mapping, the largest rhodolith beds are purported to occur off Brazil, where these communities are recorded across a wide latitudinal range (2°N-27°S). To quantify their extent, we carried out an inter-reefal seabed habitat survey on the Abrolhos Shelf (16°50'-19°45'S) off eastern Brazil, and confirmed the most expansive and contiguous rhodolith bed in the world, covering about 20,900 km(2). Distribution, extent, composition and structure of this bed were assessed with side scan sonar, remotely operated vehicles, and SCUBA. The mean rate of CaCO(3) production was estimated from in situ growth assays at 1.07 kg m(-2) yr(-1), with a total production rate of 0.025 Gt yr(-1), comparable to those of the world's largest biogenic CaCO(3) deposits. These gigantic rhodolith beds, of areal extent equivalent to the Great Barrier Reef, Australia, are a critical, yet poorly understood component of the tropical South Atlantic Ocean. Based on the relatively high vulnerability of coralline algae to ocean acidification, these beds are likely to experience a profound restructuring in the coming decades.

  16. Physiologic and metagenomic attributes of the rhodoliths forming the largest CaCO3 bed in the South Atlantic Ocean

    Science.gov (United States)

    Cavalcanti, Giselle S; Gregoracci, Gustavo B; dos Santos, Eidy O; Silveira, Cynthia B; Meirelles, Pedro M; Longo, Leila; Gotoh, Kazuyoshi; Nakamura, Shota; Iida, Tetsuya; Sawabe, Tomoo; Rezende, Carlos E; Francini-Filho, Ronaldo B; Moura, Rodrigo L; Amado-Filho, Gilberto M; Thompson, Fabiano L

    2014-01-01

    Rhodoliths are free-living coralline algae (Rhodophyta, Corallinales) that are ecologically important for the functioning of marine environments. They form extensive beds distributed worldwide, providing a habitat and nursery for benthic organisms and space for fisheries, and are an important source of calcium carbonate. The Abrolhos Bank, off eastern Brazil, harbors the world's largest continuous rhodolith bed (of ∼21 000 km2) and has one of the largest marine CaCO3 deposits (producing 25 megatons of CaCO3 per year). Nevertheless, there is a lack of information about the microbial diversity, photosynthetic potential and ecological interactions within the rhodolith holobiont. Herein, we performed an ecophysiologic and metagenomic analysis of the Abrolhos rhodoliths to understand their microbial composition and functional components. Rhodoliths contained a specific microbiome that displayed a significant enrichment in aerobic ammonia-oxidizing betaproteobacteria and dissimilative sulfate-reducing deltaproteobacteria. We also observed a significant contribution of bacterial guilds (that is, photolithoautotrophs, anaerobic heterotrophs, sulfide oxidizers, anoxygenic phototrophs and methanogens) in the rhodolith metagenome, suggested to have important roles in biomineralization. The increased hits in aromatic compounds, fatty acid and secondary metabolism subsystems hint at an important chemically mediated interaction in which a functional job partition among eukaryal, archaeal and bacterial groups allows the rhodolith holobiont to thrive in the global ocean. High rates of photosynthesis were measured for Abrolhos rhodoliths (52.16 μmol carbon m−2 s−1), allowing the entire Abrolhos rhodolith bed to produce 5.65 × 105 tons C per day. This estimate illustrates the great importance of the Abrolhos rhodolith beds for dissolved carbon production in the South Atlantic Ocean. PMID:23985749

  17. Rhodolith beds are major CaCO3 bio-factories in the tropical South West Atlantic.

    Directory of Open Access Journals (Sweden)

    Gilberto M Amado-Filho

    Full Text Available Rhodoliths are nodules of non-geniculate coralline algae that occur in shallow waters (<150 m depth subjected to episodic disturbance. Rhodolith beds stand with kelp beds, seagrass meadows, and coralline algal reefs as one of the world's four largest macrophyte-dominated benthic communities. Geographic distribution of rhodolith beds is discontinuous, with large concentrations off Japan, Australia and the Gulf of California, as well as in the Mediterranean, North Atlantic, eastern Caribbean and Brazil. Although there are major gaps in terms of seabed habitat mapping, the largest rhodolith beds are purported to occur off Brazil, where these communities are recorded across a wide latitudinal range (2°N-27°S. To quantify their extent, we carried out an inter-reefal seabed habitat survey on the Abrolhos Shelf (16°50'-19°45'S off eastern Brazil, and confirmed the most expansive and contiguous rhodolith bed in the world, covering about 20,900 km(2. Distribution, extent, composition and structure of this bed were assessed with side scan sonar, remotely operated vehicles, and SCUBA. The mean rate of CaCO(3 production was estimated from in situ growth assays at 1.07 kg m(-2 yr(-1, with a total production rate of 0.025 Gt yr(-1, comparable to those of the world's largest biogenic CaCO(3 deposits. These gigantic rhodolith beds, of areal extent equivalent to the Great Barrier Reef, Australia, are a critical, yet poorly understood component of the tropical South Atlantic Ocean. Based on the relatively high vulnerability of coralline algae to ocean acidification, these beds are likely to experience a profound restructuring in the coming decades.

  18. 改性纳米CaCO3填充PVC复合材料力学性能和转矩流变性能研究%Mechanical Property and Torque Rheological Property of PVC Composite Filled by Modified Nano-CaCO3

    Institute of Scientific and Technical Information of China (English)

    王少会; 卢尚琨; 任凤梅; 徐卫兵

    2008-01-01

    通过熔融共混法制备了PVC/改性nano-CaCO3复合材料,并测试了复合材料的力学性能和转矩流变性能.结果表明:PVC/改性nano-CaCO3复合材料的力学性能比PVC/未改性nano-CaCO3均有所提高;PVC/改性nano-CaCO3复合材料在塑化过程中各阶段的扭矩及望化时间比PVC/未改性nano-CaCO3均有所下降,其中超分散剂的改性效果最好.

  19. Influencia de la adición del BaCO3 sobre la hidratación del cemento portland

    Directory of Open Access Journals (Sweden)

    Blanco-Varela, M. T.

    1999-06-01

    Full Text Available The effect of incorporation of BaCO3 in portland cement hydration has been studied. From this study it is inferred that presence of BaCO3 in cements makes them require a higher quantity of mixing water. However, mechanical resistances do not seem negatively affected, for a formation of carboaluminates by chemical reaction between the barium carbonate and the C3A of the clinker appears. The BaCO3 reveals a retardant effect on the setting time, in presence of gypsum as much as in its absence. The BaCO3 with gypsum reacts as BaSO4, a salt of a very high stability. The formation of this barium salt inhibits the formation of ettringite in pastes. Finally, the presence of BaCO3 in cements ensures that no expansive process will occur in sulphatic means either external or internal, for carbonate is going to react with these sulphates and form BaSO4, preventing thus the formation of expansive ettringite.Se ha estudiado el efecto de la incorporación de BaCO3 en la hidratación del cemento portland. Como resultado del estudio se ha concluido que la presencia de BaCO3 en los cementos hace que éstos requieran una mayor cantidad de agua de amasado. Sin embargo, las resistencias mecánicas no se ven negativamente afectadas, ya que se produce la formación de carboaluminatos por reacción química entre el carbonato de bario y el C3A del clinker. El BaCO3 manifiesta un efecto retardador en los tiempos de fraguado, tanto en presencia como en ausencia de yeso. El BaCO3 reacciona con el yeso formando BaSO4, sal de muy elevada estabilidad. La formación de esta sal de bario inhibe la formación de ettringita en las pastas. Finalmente, indicar que la presencia de BaCO3 en los cementos asegura que éstos no experimenten procesos expansivos cuando se encuentren en medios sulfáticos externos o internos, ya que el carbonato interaccionará con dichos sulfatos formando BaSO4 e impidiendo la formación de ettringita expansiva.

  20. AgBr and g-C3N4 co-modified Ag2CO3 photocatalyst: A novel multi-heterostructured photocatalyst with enhanced photocatalytic activity

    Science.gov (United States)

    Tang, Hua; Chang, Shufang; Tang, Guogang; Liang, Wei

    2017-01-01

    Novel and highly efficient visible-light-driven g-C3N4/Ag2CO3/AgBr multi-heterostructured photocatalysts are achieved from the surface modification of g-C3N4/Ag2CO3 with AgBr nanoparticles by a facile and efficient ion-exchange method. The as-prepared g-C3N4/Ag2CO3/AgBr photocatalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), scaning electron microscopy (SEM) and UV-vis diffuse reflectance spectrometry (DRS). Compared with g-C3N4/Ag2CO3, g-C3N4/Ag2CO3/AgBr hybrids exhibit enhanced the degradation activity for typical RhB, MB, and MO dyes under visible light excitation (>420 nm). Photoluminescence (PL), photo-induced current and electrochemical impedance spectroscopy (EIS) results demonstrate the g-C3N4/Ag2CO3/AgBr heterojunctions can effectively suppress the recombination of the generated electron-hole pairs. The higher photocatalytical performance of g-C3N4/Ag2CO3/AgBr can be ascribed to the efficient separation of photogenerated electron-hole pairs due to the formation of multi-heterojunctions, in which the Ag nanoparticles acted as the charge transmission bridge. In addition, the possible transferred and separated behavior of electron-hole pairs and photocatalytic mechanisms based on the experimental results are also proposed in detail.

  1. Spectroscopic investigations on the effect of humic acid on the formation and solubility of secondary solid phases of Ln2(CO3)3

    Institute of Scientific and Technical Information of China (English)

    Stella Antoniou; Ioannis Pashalidis; Andre Gessner; Michael U Kumke

    2011-01-01

    The formation of secondary Ln(Ⅲ) solid phases (e.g., Nd2(CO3)3 and Sm2(CO3)3) was studied as a function of the humic acid concentration in 0.1 mol/L NaClO4 aqueous solution in the neutral pH range (5-6.5). The solid phases under investigation were prepared by alkaline precipitation under 100% CO2 atmosphere and characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), time-resolved laser fluorescence spectroscopy (TRLFS), diffuse reflectance ultraviolet-visible (DR-UV-Vis), Raman spectroscopy, and solubility measurements. The spectroscopic data obtained indicated that Nd2(CO3)3 and Sm2(CO3)3 were stable and remained the solubility limiting solid phases even in the presence of increased humic acid concentration (0.5 g/L) in solution.Upon base addition in the Ln(Ⅲ)-HA system, decomplexation of the previously formed Ln(Ⅲ)-humate complexes and precipitation of two distinct phases occurred, the inorganic (Ln2(CO3)3) and the organic phase (HA), which was adsorbed on the particle surface of the former.Nevertheless, humic acid affected the particle size of the solid phases. Increasing humic acid concentration resulted in decreasing crystallite size of the Nd2(CO3)3 and increasing crystallite size of the Sm2(CO3)3 solid phase, and affected inversely the solubility of the solid phases.However, this impact on the solid phase properties was expected to be of minor relevance regarding the chemical behavior and migration of trivalent lanthanides and actinides in the geosphere.

  2. 基于NASICON和Co3O4敏感电极的丙酮传感器的研究%Research of acetone sensor based on the NASICON and Co3O4 sensitive electrode

    Institute of Scientific and Technical Information of China (English)

    金贵新; 王艳丽; 安申爽; 张小水; 梁喜双

    2014-01-01

    以溶胶-凝胶法制备的NASICON为基体导电层材料,以水热法制备的纳米片状Co3O4为敏感电极材料,制备了一种检测低浓度丙酮的管式结构固体电解质型气体传感器,利用静态配气法对传感器的气敏性能进行了测试,结果表明:当工作温度为300~375℃时,传感器对体积分数为0.5× 10-6~100× 10-6的丙酮表现出了较好的气敏性能,其检测下限能达到0.5×10-6(体积分数),传感器电动势变化值(△v功与丙酮浓度的对数呈线性关系,在温度为350℃时,传感器对丙酮的灵敏度达到最大值-24.5 mV/decade,另外,该传感器还具有较快的响应恢复速度和较好的选择性.

  3. Dexamethasone-loaded poly(3-hydroxybutyrate-co-3-hydroxyvalerate) microparticles for controlled release;Microparticulas de poli(3-hidroxibutirato-co-3-hidroxivalerato) para a liberacao modificada da dexametasona

    Energy Technology Data Exchange (ETDEWEB)

    Riekes, Manoela Klueppel; Paula, Josiane Padilha de; Farago, Paulo Vitor, E-mail: pvfarago@uepg.b [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil); Zawadzki, Sonia Faria [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Quimica

    2009-07-01

    Dexamethasone (DEX) has been widely used for the treatment of ulcerative colitis. The aim of the present study was to obtain DEX-loaded poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) microparticles prepared by simple emulsion/solvent evaporation method. The drug loading and the encapsulation efficiency were determined by a previously validated UV method at 233 nm. Morphological, spectroscopical and dissolution analyses were also performed. The microparticles (formulation F no. 0, F no. 1 and F no. 2) were successfully obtained as off-white powders. A drug loading of 92.27 mg.g {sup -1} and 218.54 mg.g{sup -1} and an encapsulation efficiency of 93.96 % and 87.43 % were respectively observed for F no. 1 and F no. 2. Particles showed spherical and rough aspect by SEM. X-ray diffraction analysis demonstrated that the encapsulation reduced the drug crystallinity. FTIR spectra showed that no chemical bonding occurred between PHBV and DEX. Drug-loaded microparticles revealed controlled release profiles compared to pure DEX. (author)

  4. In-Situ Hydrothermal Synthesis of Bi-Bi2O2CO3 Heterojunction Photocatalyst with Enhanced Visible Light Photocatalytic Activity

    Science.gov (United States)

    Kar, Prasenjit; Maji, Tuhin Kumar; Nandi, Ramesh; Lemmens, Peter; Pal, Samir Kumar

    2017-04-01

    Bismuth containing nanomaterials recently received increasing attention with respect to environmental applications because of their low cost, high stability and nontoxicity. In this work, Bi-Bi2O2CO3 heterojunctions were fabricated by in-situ decoration of Bi nanoparticles on Bi2O2CO3 nanosheets via a simple hydrothermal synthesis approach. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) were used to confirm the morphology of the nanosheet-like heterostructure of the Bi-Bi2O2CO3 composite. Detailed ultrafast electronic spectroscopy reveals that the in-situ decoration of Bi nanoparticles on Bi2O2CO3 nanosheets exhibit a dramatically enhanced electron-hole pair separation rate, which results in an extraordinarily high photocatalytic activity for the degradation of a model organic dye, methylene blue (MB) under visible light illumination. Cycling experiments revealed a good photochemical stability of the Bi-Bi2O2CO3 heterojunction under repeated irradiation. Photocurrent measurements further indicated that the heterojunction incredibly enhanced the charge generation and suppressed the charge recombination of photogenerated electron-hole pairs.

  5. Microwave synthesis and effect of CTAB on ferromagnetic properties of NiO, Co3O4 and NiCo2O4 nanostructures

    Science.gov (United States)

    Anandha Babu, G.; Ravi, G.; Hayakawa, Y.

    2015-04-01

    Cubic-structured NiO, Co3O4 and spinel-structured NiCo2O4 were synthesized via microwave route. The structural properties of NiO, Co3O4 and NiCo2O4 nanostructures were investigated by X-ray diffraction analysis, and it showed smaller crystallite size for NiO than Co3O4 and NiCo2O4 by using Williamson-Hall method. Flake-like and hexagonal plate-like morphologies were ascertained from HRSEM and TEM analyses. Optical properties of these materials were investigated by photoluminescence study, and it presents the band edge emission for all materials with supplementary emissions in visible region due to the presence of defects such as vacancy and interstitial. Raman and FTIR spectra provide the functional characteristics of NiO, Co3O4 and NiCo2O4 nanostructures. XPS measurement revealed the purity and composition of these nanostructures. Room temperature magnetic measurements were investigated using vibrating sample magnetometer. The low coercivity and remanent magnetization for NiO, Co3O4 and NiCo2O4 nanostructures confirmed that these nanoparticles exhibit a weak ferromagnetic behaviour.

  6. A Computational Study on the Mechanism for the K_2CO_3-catalyzed Reaction of Carbon Dioxide and 1-Chlo-2-propanol

    Institute of Scientific and Technical Information of China (English)

    张福兰; 万邦江; 黄辉胜

    2012-01-01

    The microcosmic reaction mechanism of K2CO3-catalyzed 1-chlo-2-propanol and carbon dioxide has been investigated by density functional theory(DFT) at the GGA/PW91/DNP level.We optimize the geometric configurations of reactants,intermediates,transition states,and products.The energy analysis calculation approves the authenticity of intermediates and transition states.According to our calculations,four feasible reaction pathways are found.The main pathway of the reaction is ReA → IMA1 → TSA1 → IMA2 → IMA5 → TSA5 → P.Besides,we also in-vestigate the reaction mechanism of 1-chlo-2-propanol and carbon dioxide without K2CO3-catalyzation by the same theory and level.The computational results indicate that the activation barrier with K2CO3-catalyzed is smaller than the activation barrier without K2CO3-catalyzed.That is to say,K2CO3 can promote the reaction to give the product in a high yield,which is in agreement with the experimental results.

  7. Preparation and catalytic effect of porous Co3O4 on the hydrogen storage properties of a Li-B-N-H system

    Directory of Open Access Journals (Sweden)

    You Li

    2017-02-01

    Full Text Available A porous Co3O4 with a particle size of 1–3 µm was successfully prepared by heating Co-based metal organic frameworks MOF-74(Co up to 500 °C in air atmospheric conditions. The as-prepared porous Co3O4 significantly reduced the dehydrogenation temperatures of the LiBH4-2LiNH2 system and improved the purity of the released hydrogen. The LiBH4-2LiNH2-0.05/3Co3O4 sample started to release hydrogen at 140 °C and released hydrogen levels of approximately 9.7 wt% at 225 °C. The end temperature for hydrogen release was lowered by 125 °C relative to that of the pristine sample. Structural analyses revealed that the as-prepared porous Co3O4 is in-situ reduced to metallic Co, which functions as an active catalyst, reducing the kinetic barriers and lowering the dehydrogenation temperatures of the LiBH4-2LiNH2 system. More importantly, the porous Co3O4-containing sample exhibited partially improved reversibility for hydrogen storage in the LiBH4-2LiNH2 system.

  8. Hydrothermal synthesis of K2CO3-promoted hydrotalcite from hydroxide-form precursors for novel high-temperature CO2 sorbent.

    Science.gov (United States)

    Jang, Hee Jin; Lee, Chan Hyun; Kim, Suji; Kim, Sung Hyun; Lee, Ki Bong

    2014-05-14

    In many materials for CO2 sorption, hydrotalcite is attracting substantial attention as a high temperature (200-500 °C) CO2 sorbent because of its fast sorption/desorption kinetics and easy regenerability. However, the CO2-sorption capacity of conventional hydrotalcite is relatively low for large-scale commercial use. To enhance CO2-sorption capacity, hydrotalcite is conventionally impregnated with alkali metals such as K2CO3. Although K2CO3-impregnated hydrotalcite has high CO2-sorption capacity, the preparation method takes long time and is inconvenient because hydrotalcite synthesis step and alkali metal impregnation step are separated. In this study, K2CO3-promoted hydrotalcite was newly synthesized from hydroxide-form percursors by a simple and eco-friendly method without a solvent-consuming washing step. Analysis based on X-ray diffraction indicated that the prepared samples had structures of well-defined hydrotalcite crystalline and un-reacted Mg(OH)2 precursor. Moreover, K2CO3 was successfully incorporated in hydrotalcite during the synthesis step. The prepared K2CO3-promoted hydrotalcite showed high CO2-sorption capacity and had potential for use as a high-temperature CO2 sorbent.

  9. Diamond formation in the deep lower mantle: a high-pressure reaction of MgCO3 and SiO2

    Science.gov (United States)

    Maeda, Fumiya; Ohtani, Eiji; Kamada, Seiji; Sakamaki, Tatsuya; Hirao, Naohisa; Ohishi, Yasuo

    2017-01-01

    Diamond is an evidence for carbon existing in the deep Earth. Some diamonds are considered to have originated at various depth ranges from the mantle transition zone to the lower mantle. These diamonds are expected to carry significant information about the deep Earth. Here, we determined the phase relations in the MgCO3-SiO2 system up to 152 GPa and 3,100 K using a double sided laser-heated diamond anvil cell combined with in situ synchrotron X-ray diffraction. MgCO3 transforms from magnesite to the high-pressure polymorph of MgCO3, phase II, above 80 GPa. A reaction between MgCO3 phase II and SiO2 (CaCl2-type SiO2 or seifertite) to form diamond and MgSiO3 (bridgmanite or post-perovsktite) was identified in the deep lower mantle conditions. These observations suggested that the reaction of the MgCO3 phase II with SiO2 causes formation of super-deep diamond in cold slabs descending into the deep lower mantle. PMID:28084421

  10. Microstructure and Magnetic Properties of Highly Ordered SBA-15 Nanocomposites Modified with Fe2O3 and Co3O4 Nanoparticles

    Directory of Open Access Journals (Sweden)

    P. F. Wang

    2012-01-01

    Full Text Available Owing to the unique order mesopores, mesoporous SBA-15 could be used as the carrier of the magnetic nanoparticles. The magnetic nanoparticles in the frame and the mesopores lead to the exchange-coupling interaction or other interactions, which could improve the magnetic properties of SBA-15 nanocomposites. Mesoporous Fe/SBA-15 had been prepared via in situ anchoring Fe2O3 into the frame and the micropores of SBA-15 using the sol-gel and hydrothermal processes. Co3O4 nanoparticles had been impregnated into the mesopores of Fe/SBA-15 to form mesoporous Fe/SBA-15-Co3O4 nanocomposites. XRD, HRTEM, VSM, and N2 physisorption isotherms were used to characterize the mesostructure and magnetic properties of the SBA-15 nanocomposites, and all results indicated that the Fe2O3 nanoparticles presented into the frame and micropores, while the Co3O4 nanoparticles existed inside the mesopores of Fe/SBA-15. Furthermore, the magnetic properties of SBA-15 could be conveniently adjusted by the Fe2O3 and Co3O4 magnetic nanoparticles. Fe/SBA-15 exhibited ferromagnetic properties, while the impregnation of Co3O4 nanoparticles greatly improved the coercivity with a value of 1424.6 Oe, which was much higher than that of Fe/SBA-15.

  11. Effect of Pr, Sm, and Tb Doping on the Morphology, Crystallite Size, and N2O Decomposition Activity of Co3O4 Nanorods

    Directory of Open Access Journals (Sweden)

    Bahaa M. Abu-Zied

    2015-01-01

    Full Text Available Cobalt(II,III oxide, Co3O4, is a promising catalyst for nitrous oxide direct decomposition. In this paper we report effect of doping with some rare earth (RE elements (Pr, Sm, and Tb on the morphology and crystallite size of Co3O4 nanorods. The various precursors (RE/Co oxalates were prepared via the microwave assisted method and subsequent calcination. The decomposition pathway of these precursors was followed using thermogravimetric analysis (TGA. Based on thermal analysis results, Pr-, Sm-, and Tb-doped Co3O4 samples were obtained via the calcination in static air at 500°C for their oxalate precursors. X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR, scanning electron microscopy (SEM, transmission electron microscopy (TEM, and hydrogen temperature programmed reduction (H2-TPR were used to characterize the RE-doped cobalt oxide catalysts. The activity of the prepared catalysts was investigated for N2O direct decomposition and compared with that of the undoped Co3O4 catalyst. It was shown that the promoted Co3O4 catalysts revealed higher activity compared to the unpromoted one. The dependence of the activity on both the catalysts particle size and the reduction behaviour was discussed.

  12. Net Loss of CaCO3 from a subtropical calcifying community due to seawater acidification: mesocosm-scale experimental evidence

    Directory of Open Access Journals (Sweden)

    K. S. Rodgers

    2009-08-01

    Full Text Available Acidification of seawater owing to oceanic uptake of atmospheric CO2 originating from human activities such as burning of fossil fuels and land-use changes has raised serious concerns regarding its adverse effects on corals and calcifying communities. Here we demonstrate a net loss of calcium carbonate (CaCO3 material as a result of decreased calcification and increased carbonate dissolution from replicated subtropical coral reef communities (n=3 incubated in continuous-flow mesocosms subject to future seawater conditions. The calcifying community was dominated by the coral Montipora capitata. Daily average community calcification or Net Ecosystem Calcification (NEC=CaCO3 production – dissolution was positive at 3.3 mmol CaCO3 m−2 h−1 under ambient seawater pCO2 conditions as opposed to negative at −0.04 mmol CaCO3 m−2 h−1 under seawater conditions of double the ambient pCO2. These experimental results provide support for the conclusion that some net calcifying communities could become subject to net dissolution in response to anthropogenic ocean acidification within this century. Nevertheless, individual corals remained healthy, actively calcified (albeit slower than at present rates, and deposited significant amounts of CaCO3 under the prevailing experimental seawater conditions of elevated pCO2.

  13. Net Loss of CaCO3 from a subtropical calcifying community due to seawater acidification: Mesocosm-scale experimental evidence

    Science.gov (United States)

    Andersson, A.J.; Kuffner, I.B.; MacKenzie, F.T.; Jokiel, P.L.; Rodgers, K.S.; Tan, A.

    2009-01-01

    Acidification of seawater owing to oceanic uptake of atmospheric CO 2 originating from human activities such as burning of fossil fuels and land-use changes has raised serious concerns regarding its adverse effects on corals and calcifying communities. Here we demonstrate a net loss of calcium carbonate (CaCO3) material as a result of decreased calcification and increased carbonate dissolution from replicated subtropical coral reef communities (N=3) incubated in continuous-flow mesocosms subject to future seawater conditions. The calcifying community was dominated by the coral Montipora capitata. Daily average community calcification or Net Ecosystem Calcification (NECC=CaCO3 production - dissolution) was positive at 3.3 mmol CaCO3 m-2 h-1 under ambient seawater pCO2 conditions as opposed to negative at -0.04 mmol CaCO3 m-2 h-1 under seawater conditions of double the ambient pCO2. These experimental results provide support for the conclusion that some net calcifying communities could become subject to net dissolution in response to anthropogenic ocean acidification within this century. Nevertheless, individual corals remained healthy, actively calcified (albeit slower than at present rates), and deposited significant amounts of CaCO3 under the prevailing experimental seawater conditions of elevated pCO2.

  14. Rational Design of 1-D Co3O4 Nanofibers@Low content Graphene Composite Anode for High Performance Li-Ion Batteries

    Science.gov (United States)

    Cho, Su-Ho; Jung, Ji-Won; Kim, Chanhoon; Kim, Il-Doo

    2017-01-01

    Cobalt oxide that has high energy density, is the next-generation candidate as the anode material for LIBs. However, the practical use of Co3O4 as anode material has been hindered by limitations, especially, low electrical conductivity and pulverization from large volume change upon cycling. These features lead to hindrance to its electrochemical properties for lithium-ion batteries. To improve electrochemical properties, we synthesized one-dimensional (1-D) Co3O4 nanofibers (NFs) overed with reduced graphene oxide (rGO) sheets by electrostatic self-assembly (Co3O4 NFs@rGO). The flexible graphene oxide sheets not only prevent volume changes of active materials upon cycling as a clamping layer but also provide efficient electrical pathways by three-dimensional (3-D) network architecture. When applied as an anode for LIBs, the Co3O4 NFs@rGO exhibits superior electrochemical performance: (i) high reversible capacity (615 mAh g−1 and 92% capacity retention after 400 cycles at 4.0 A g−1) and (ii) excellent rate capability. Herein, we highlighted that the enhanced conversion reaction of the Co3O4 NFs@rGO is attributed to effective combination of 1-D nanostructure and low content of rGO (~3.5 wt%) in hybrid composite. PMID:28345589

  15. Polyaniline-decorated {001} facets of Bi2O2CO3 nanosheets: in situ oxygen vacancy formation and enhanced visible light photocatalytic activity.

    Science.gov (United States)

    Zhao, Ziyan; Zhou, Ying; Wang, Fang; Zhang, Kunhao; Yu, Shan; Cao, Kun

    2015-01-14

    Polyaniline (PANI)-decorated {001} facets of Bi2O2CO3 nanosheets were synthesized by a low-temperature chemical method. We demonstrate that the strong interfacial interactions between Bi2O2CO3 {001} facets and PANI could promote in situ formation of oxygen vacancy at the interface confirmed by both density functional theory calculations and electron spin resonance experiments, which is due to the high oxygen density characteristic of Bi2O2CO3 {001} facets. In addition, such interfacial interaction also leads to a 0.38 eV positive shifting of the valence band of Bi2O2CO3. Importantly, the decorated PANI can stabilize these interfacial oxygen vacancies. Therefore, the migration and separation of photogenerated carriers have been improved significantly evidenced by electrochemical impedance spectroscopy, photoluminescence, and nanosecond time-resolved fluorescence-decay spectra, resulting in a 4.5 times higher activity toward photodegradation of Rhodamine B and a 6 times higher photocurrent density compared to their corresponding bare Bi2O2CO3. The finding of the in situ oxygen vacancy formation at the interface could provide some hints for the deep understanding of the interactions between PANI and crystal facets of semiconductors to develop highly efficient photocatalysts.

  16. [Co(salen)] derived Co/Co3O4 nanoparticle@carbon matrix as high-performance electrode for energy storage applications

    Science.gov (United States)

    Duraisamy, E.; Gurunathan, P.; Das, Himadri T.; Ramesha, K.; Elumalai, P.

    2017-03-01

    Cobalt/cobalt oxide nanoparticle-embedded in a carbon matrix was synthesized by one spot pyrolysis of cobalt salen complex [Co(salen)] at 800 °C in an argon atmosphere. The X-ray diffraction studies confirmed the presence of Co and Co3O4 in the carbon matrix. The SEM and TEM observations showed the homogeneous distribution of the Co/Co3O4 grains on the carbon matrix. Cyclic voltammograms and galvanostatic charge-discharge studies done on the CR2032 coin cell confirmed that the Co/Co3O4@carbon matrix was electrochemically active. A stable specific capacity as high as 1000 mA h g-1 has been observed over 50 charge-discharge cycles at C/5 rate. It is believed that the carbon matrix acted both as a spacer to accommodate volume changes during Li intercalation-deintercalation process and also as conductive network leading to the excellent electrochemical performance of the Co/Co3O4@carbon matrix. Further, supercapacitor studies revealed that a specific capacitance of 615 F g-1 at 1 A g-1 has been exhibited by the Co/Co3O4@carbon matrix electrode in 1 M KOH with high Coulombic efficiency (92%) as well as excellent cycling stability for 5000 cycles.

  17. Co@Co3 O4 @PPD Core@bishell Nanoparticle-Based Composite as an Efficient Electrocatalyst for Oxygen Reduction Reaction.

    Science.gov (United States)

    Wang, Zhijuan; Li, Bing; Ge, Xiaoming; Goh, F W Thomas; Zhang, Xiao; Du, Guojun; Wuu, Delvin; Liu, Zhaolin; Andy Hor, T S; Zhang, Hua; Zong, Yun

    2016-05-01

    Durable electrocatalysts with high catalytic activity toward oxygen reduction reaction (ORR) are crucial to high-performance primary zinc-air batteries (ZnABs) and direct methanol fuel cells (DMFCs). An efficient composite electrocatalyst, Co@Co3 O4 core@shell nanoparticles (NPs) embedded in pyrolyzed polydopamine (PPD) is reported, i.e., in Co@Co3 O4 @PPD core@bishell structure, obtained via a three-step sequential process involving hydrothermal synthesis, high temperature calcination under nitrogen atmosphere, and gentle heating in air. With Co@Co3 O4 NPs encapsulated by ultrathin highly graphitized N-doped carbon, the catalyst exhibits excellent stability in aqueous alkaline solution over extended period and good tolerance to methanol crossover effect. The integration of N-doped graphitic carbon outer shell and ultrathin nanocrystalline Co3 O4 inner shell enable high ORR activity of the core@bishell NPs, as evidenced by ZnABs using catalyst of Co@Co3 O4 @PPD in air-cathode which delivers a stable voltage profile over 40 h at a discharge current density of as high as 20 mA cm(-2) .

  18. Understanding Structure-Function Relationship in Hybrid Co3O4-Fe2O3/C Lithium-Ion Battery Electrodes.

    Science.gov (United States)

    Sultana, Irin; Rahman, Md Mokhlesur; Ramireddy, Thrinathreddy; Sharma, Neeraj; Poddar, Debasis; Khalid, Abbas; Zhang, Hongzhou; Chen, Ying; Glushenkov, Alexey M

    2015-09-23

    A range of high-capacity Li-ion anode materials (conversion reactions with lithium) suffer from poor cycling stability and limited high-rate performance. These issues can be addressed through hybridization of multiple nanostructured components in an electrode. Using a Co3O4-Fe2O3/C system as an example, we demonstrate that the cycling stability and rate performance are improved in a hybrid electrode. The hybrid Co3O4-Fe2O3/C electrode exhibits long-term cycling stability (300 cycles) at a moderate current rate with a retained capacity of approximately 700 mAh g(-1). The reversible capacity of the Co3O4-Fe2O3/C electrode is still about 400 mAh g(-1) (above the theoretical capacity of graphite) at a high current rate of ca. 3 A g(-1), whereas Co3O4-Fe2O3, Fe2O3/C, and Co3O4/C electrodes (used as controls) are unable to operate as effectively under identical testing conditions. To understand the structure-function relationship in the hybrid electrode and the reasons for the enhanced cycling stability, we employed a combination of ex situ and in situ techniques. Our results indicate that the improvements in the hybrid electrode originate from the combination of sequential electrochemical activity of the transition metal oxides with an enhanced electronic conductivity provided by percolating carbon chains.

  19. Photocatalytic oxidation removal of Hg0 using ternary Ag/AgI-Ag2CO3 hybrids in wet scrubbing process under fluorescent light

    Science.gov (United States)

    Zhang, Anchao; Zhang, Lixiang; Chen, Xiaozhuan; Zhu, Qifeng; Liu, Zhichao; Xiang, Jun

    2017-01-01

    A series of ternary Ag/AgI-Ag2CO3 photocatalysts synthesized using a facile coprecipitation method were employed to investigate their performances of Hg0 removal in a wet scrubbing reactor. The hybrids were characterized by N2 adsorption-desorption, XRD, SEM-EDS, HRTEM, XPS, DRS and ESR. The photocatalytic activities of Hg0 removal were evaluated under fluorescent light. The results showed that AgI content, fluorescent light irradiation, reaction temperature all showed significant influences on Hg0 removal. NO exhibited significant effect on Hg0 removal in comparison to SO2. Among these ternary Ag/AgI-Ag2CO3 hybrids, Ag/AgI(0.1)-Ag2CO3 showed the highest Hg0 removal efficiency, which could be ascribed to the effective separation of photogenerated electron-hole pairs between AgI and Ag2CO3 and the surface plasmon resonance (SPR) effect in the visible region by metallic silver nanoparticles (Ag0 NPs). The trapping studies of reactive radicals showed that the superoxide radicals (rad O2-) may play a key role in Hg0 removal under fluorescent light. According to the experimental and characterization results, a possible photocatalytic oxidation mechanism for enhanced Hg0 removal over Ag/AgI(0.1)-Ag2CO3 hybrid under fluorescent light was proposed.

  20. High-performance two-ply yarn supercapacitors based on carbon nanotube yarns dotted with Co3 O4 and NiO nanoparticles.

    Science.gov (United States)

    Su, Fenghua; Lv, Xiaoming; Miao, Menghe

    2015-02-18

    Yarn supercapacitors are promising power sources for flexible electronic applications that require conventional fabric-like durability and wearer comfort. Carbon nanotube (CNT) yarn is an attractive choice for constructing yarn supercapacitors used in wearable textiles because of its high strength and flexibility. However, low capacitance and energy density limits the use of pure CNT yarn in wearable high-energy density devices. Here, transitional metal oxide pseudocapacitive materials NiO and Co3 O4 are deposited on as-spun CNT yarn surface using a simple electrodeposition process. The Co3 O4 deposited on the CNT yarn surface forms a uniform hybridized CNT@Co3 O4 layer. The two-ply supercapacitors formed from the CNT@Co3 O4 composite yarns display excellent electrochemical properties with very high capacitance of 52.6 mF cm(-2) and energy density of 1.10 μWh cm(-2) . The high performance two-ply CNT@Co3 O4 yarn supercapacitors are mechanically and electrochemically robust to meet the high performance requirements of power sources for wearable electronics.