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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.

    Directory of Open Access Journals (Sweden)

    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. Homotopy Characterization of ANR Function Spaces

    Directory of Open Access Journals (Sweden)

    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.

  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. [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. PMID:19375827

  10. 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

    International Nuclear Information System (INIS)

    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.)

  11. 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...

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

    Directory of Open Access Journals (Sweden)

    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 (...

  13. 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.)

  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. 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...

  16. An integrated approach to demonstrating the ANR pathway of proanthocyanidin biosynthesis in plants.

    Science.gov (United States)

    Peng, Qing-Zhong; Zhu, Yue; Liu, Zhong; Du, Ci; Li, Ke-Gang; Xie, De-Yu

    2012-09-01

    Proanthocyanidins (PAs) are oligomers or polymers of plant flavan-3-ols and are important to plant adaptation in extreme environmental conditions. The characterization of anthocyanidin reductase (ANR) and leucoanthocyanidin reductase (LAR) has demonstrated the different biogenesis of four stereo-configurations of flavan-3-ols. It is important to understand whether ANR and the ANR pathway widely occur in the plant kingdom. Here, we report an integrated approach to demonstrate the ANR pathway in plants. This includes different methods to extract native ANR from different tissues of eight angiosperm plants (Lotus corniculatus, Desmodium uncinatum, Medicago sativa, Hordeum vulgare, Vitis vinifera, Vitis bellula, Parthenocissus heterophylla, and Cerasus serrulata) and one fern plant (Dryopteris pycnopteroides), a general enzymatic analysis approach to demonstrate the ANR activity, high-performance liquid chromatography-based fingerprinting to demonstrate (-)-epicatechin and other flavan-3-ol molecules, and phytochemical analysis of PAs. Results demonstrate that in addition to leaves of M. sativa, tissues of other eight plants contain an active ANR pathway. Particularly, the leaves, flowers and pods of D. uncinatum, which is a model plant to study LAR and the LAR pathways, are demonstrated to express an active ANR pathway. This finding suggests that the ANR pathway involves PA biosynthesis in D. uncinatum. In addition, a sequence BLAST analysis reveals that ANR homologs have been sequenced in plants from both gymnosperms and angiosperms. These data show that the ANR pathway to PA biosynthesis occurs in both seed and seedless vascular plants. PMID:22678031

  17. Introduction of apple ANR genes into tobacco inhibits expression of both CHI and DFR genes in flowers, leading to loss of anthocyanin

    OpenAIRE

    Han, Yuepeng; Vimolmangkang, Sornkanok; Soria-Guerra, Ruth Elena; Schuyler S Korban

    2012-01-01

    Three genes encoding anthocyanidin reductase (ANR) in apple (Malus×domestica Borkh.), designated MdANR1, MdANR2a, and MdANR2b, have been cloned and characterized. MdANR1 shows 91% identity in coding DNA sequences with MdANR2a and MdANR2b, while MdANR2a and MdANR2b are allelic and share 99% nucleotide sequence identity in the coding region. MdANR1 and MdANR2 genes are located on linkage groups 10 and 5, respectively. Expression levels of both MdANR1 and MdANR2 genes are generally higher in yel...

  18. Dualist heresy in Aquitaine and the Agenais, c.1000-c.1249

    OpenAIRE

    Taylor, Claire

    1999-01-01

    This thesis offers an account of dualist heresy in medieval Aquitaine. The first part asserts that the heresy referred to in early eleventh-century sources was dualist and originated in Balkan Bogomilism. It does this by combining two established methodologies. Through the first, reading the sources in their social context, it finds the poor experiencing increased poverty and oppression, and that some amongst the laity and clergy were observing signs prefiguring The End of historical time. No...

  19. Regional trajectories of innovation in Green Chemistry: Evidence from the Aquitaine region (In French)

    OpenAIRE

    Vanessa OLTRA (E3i-IFReDE-GRES); Maïder SAINT-JEAN (E3i, IFReDE-GRES)

    2012-01-01

    This article tries to apprehend the technological trajectories that develop in Aquitaine region in the field of green chemistry (GC). Breschi’s research works are used to stress that spatial patterns of innovation vary greatly amongst sectors according to the specific features of the underlying technology, as summarized by the concept of technological regime. In such a perspective, we take into account the role of industrial structures and technological regimes to apprehend regional trajector...

  20. 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...

  1. Modelling of Aquitaine II pipe whipping test with the EUROPLEXUS fast dynamics code

    International Nuclear Information System (INIS)

    This paper presents a numerical simulation with the EUROPLEXUS fast dynamics software of a pipe whipping phenomenon occurring in the thermal hydraulic conditions of a loss of coolant accident in a PWR primary circuit. Different physical phenomena take place simultaneously during the rupture and the whipping of the pipe such as plasticity, contact, large displacements, two-phase flow regime and fluid structure interaction. Two kinds of numerical models - a simplified pipeline model and a mixed 1D/3D model - are considered and compared throughout modelling and computation. Numerical results are compared with experimental data belonging to the Aquitaine II test campaign

  2. Le patrimoine naturel aquitain vu du Web : discours, valeurs, fonctions

    OpenAIRE

    Bouisset, Christine; Degrémont, Isabelle; Sevilla, Juan

    2016-01-01

    Si l’appropriation patrimoniale a longtemps été l’apanage d’acteurs scientifiques, érudits et largement institutionnels, les nouvelles technologies de communication permettent l’expression et la diffusion d’un discours patrimonial plus varié. À partir d’une étude de cas, l’Aquitaine et son traitement sur le Web, nous nous proposons donc de montrer la diversité tant dans les lieux choisis comme patrimoines que dans les acteurs au sens large qui participent au processus de patrimonialisation. L...

  3. Regional experience of evaluation of professional practice and quality assurance implementation in Aquitaine.

    Science.gov (United States)

    Michel, P; Capdenat, E; Raymond, J M; Maurette, P; Daubech, L; Salamon, R; Amouretti, M

    1997-06-01

    We report the establishment of a voluntary programme for developing the assessment of professional practice and quality assurance conducted since 1989 in the Aquitaine region of south-west France. This experience, in a region where there are 14,000 hospital beds in about a hundred institutions, has aimed at two objectives: (1) the adoption by the region's health professionals of medical guidelines for good practice and methods for measuring quality and outcomes obtained, by means of university training in evaluation and the conducting of several surveys of professional practice and clinical audits; (2) similar adoption by the regional political, administrative and medical directors of quality assurance procedures defined by an organizational audit concerning the prescription of preoperative tests in the university hospital and in the main public hospitals of the region. The critical impetus that this experience has created, together with other factors related to the political decision-makers and health managers of the region, has led to an operational regional structure for developing clinical evaluation and quality in Aquitaine. PMID:9209920

  4. [Morning snack offer in kindergarten: outlook and practices in Aquitaine, France, between 2004 and 2008].

    Science.gov (United States)

    Thibault, H; Carriere, C; Langevin, C; Atchoarena, S; Delmas, C; Baratchart, B-A; Ruello, M; Maurice-Tison, S

    2010-11-01

    The Nutrition, Prevention and Health for Children and Teenagers in Aquitaine program is a regional implementation of the French National Program of Nutrition and Health (PNNS). The first of two surveys of a representative sample of Aquitaine preschools was conducted in 2004-2005. This survey showed that more than 2/3 of teachers offered a morning snack to their pupils at around 10 o'clock in the morning, mainly composed of sweet cakes, cookies, or candies. Following this initial survey, actions were implemented starting in September 2005, aiming to stop systematic morning snacks or improve their composition. The same survey was repeated during 2007-2008 in order to analyze the changes in morning snack practices in preschools between 2004-2005 and 2007-2008. Data were collected from teachers of Aquitaine's preschools who filled out questionnaires. Schools were randomly chosen according to their size and whether or not they belonged to a priority education zone (ZEP). The results show that 57.9% of teachers organized a morning snack in 2007-2008, versus 68.7% in 2004-2005. In 2004-2005, 22% of teachers considered the morning snack as "unjustified" compared to 44% in 2007-2008. The composition of morning snacks improved: 17.7% of teachers offered fruit and/or milk in 2007-2008 versus 8.5% in 2004-2005. Morning snacks composed of other foods (such as sweets, chocolate pieces, cookies, pastries, bread, fruit juice) decreased from 60.2% in 2004-2005 to 40.2% in 2007-2008. In 2007-2008, 19% of the teachers reported that children had snacks in their schoolbag versus 34% in 2004-2005. The proportion of teachers reporting children having snacks in their schoolbag decreased from 34% in 2004-2005 to 19% in 2007-2008. Comparison between these two surveys is encouraging as it shows an improvement of the perception and practices of teachers regarding morning snacks. These results encourage the partners of this program to continue the fieldwork actions. PMID:20863673

  5. La résidence secondaire en Aquitaine : profils territoriaux

    OpenAIRE

    Meyer, Anne-Marie

    2016-01-01

    Le parc de la résidence secondaire s’est constitué progressivement, privilégiant, en fonction des périodes, certains espaces ou certaines formes de construction. Il en découle une forte hétérogénéité tant spatiale que morphologique, reflet de l’évolution de la société. Ce portrait spatio-temporel du parc de la résidence secondaire sera esquissé à l’aide de l’exemple aquitain. Il est fondé sur une analyse des données issues de la base FILOCOM mise à disposition par la direction générale des Im...

  6. Gouvernance territoriale durable via les PME : L’exemple de la région Aquitaine

    OpenAIRE

    Anne Musson

    2011-01-01

    A partir d’une enquête auprès de 18 PME aquitaines, nous analysons la représentation qu’elles se font du développement durable, de leurs territoires et de leurs relations avec les collectivités locales. Grâce à une analyse textuelle, nous montrons que l’hypothèse d’un développement durable local impulsé par les PME semble à ce jour réaliste. En maximisant le bien-être de la population, une politique volontariste de la part des collectivités locales constituerait alors le socle d’une attractiv...

  7. 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

  8. Melting Relations of Multicomponent Carbonate System MgCO3 - FeCO3- CaCO3- Na2CO3 at 12-23 GPa

    Science.gov (United States)

    Spivak, Anna; Solopova, Natalia; Litvin, Yuriy; Dubrovinsky, Leonid; Zakharchenko, Egor

    2014-05-01

    Considerable attention is focused on high-pressure high-temperature experimental study of melting phase relations of carbonates which were involved into a 'super-deep' diamond genesis. High-pressure stability of carbonate melts and their role in 'ultra-deep' diamonds genesis are most essential. Experimental study of melting relations of multicomponent carbonate system was carried out using multi-anvil press at the pressures 12 - 23 GPa and temperatures 800 to 1650 oC. Chemical compositions of starting carbonate system used for melting experiment were prepared by mixing: FeCO3 - 26,00; MgCO3- 26,00; CaCO3 - 25,00; Na2CO3 - 23,00 wt %. A region of partial melting for the system is experimentally determined. The partial melting field is arranged between low-temperature boundary of eutectics melting (solidus line) of the multicomponent carbonate and the boundary of complete melting (liquidus line) at higher temperature. From experimental observations, a Mg-Fe carbonate solid solution is the liquidus phase. At temperature lowering, the assemblage (Mg,Fe)CO3 + (Ca,Na2,Fe)CO3 + L (liquid) is formed. Then, the invariant eutectic assemblage (Mg,Fe)CO3 + (Ca,Na2,Fe)CO3 + Na2(Ca,Fe)(CO3)2+ L (liquid) which is determining for subsolidus assemblage (Mg,Fe)CO3 + (Ca,Na2,Fe)CO3 + Na2(Ca,Fe)(CO3)2 is formed. Next to liquidus line is one-phase field of completely miscible multicomponent carbonate melt. On the whole, the results demonstrate phase relations of solid carbonates and multicomponent carbonate liquid in the immediate vicinity to the low-temperature melting boundary. The early melting of the multicomponent carbonate system is compatible with the lower mantle geothermal conditions because the primary melting temperatures are noticeably below than the geothermal values. It is significant that multicomponent carbonate melts are stable and completely miscible under conditions as partial so complete melting. Thus, high-pressure high-temperature experimental data demonstrate

  9. Gouvernance territoriale et jeux de pouvoirs dans les espaces du vin en Aquitaine, Bordeaux - Bergerac - Jurançon

    OpenAIRE

    Boivin, Nicolas

    2008-01-01

    The spaces of wine in Aquitaine (Bordeaux, Bergerac, Jurançon, place of sud west of France) are in mutation. They have to face the reforms of the greats institutions, in particular INAO. The territorial division becomes the spaces stake. Furthermore, to can answer at the globalized request, the producers, the traders and the others actors of the world of wine establish a governance. She pass by an implementation to a new decisional level : the ponds of production. This mode of territorial man...

  10. Global regulator Anr represses PlcH phospholipase activity in Pseudomonas aeruginosa when oxygen is limiting

    OpenAIRE

    Jackson, Angelyca A.; Daniels, Emily F.; Hammond, John H.; Willger, Sven D.; Hogan, Deborah A.

    2014-01-01

    Haemolytic phospholipase C (PlcH) is a potent virulence and colonization factor that is expressed at high levels by Pseudomonas aeruginosa within the mammalian host. The phosphorylcholine liberated from phosphatidylcholine and sphingomyelin by PlcH is further catabolized into molecules that both support growth and further induce plcH expression. We have shown previously that the catabolism of PlcH-released choline leads to increased activity of Anr, a global transcriptional regulator that pro...

  11. 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. PMID:26119362

  12. 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.

  13. Synthesis of the 1. ANR Energy Assessment colloquium - Which research for tomorrow's energy?

    International Nuclear Information System (INIS)

    Proposed by representatives of the main involved companies, agencies and institutions, the contributions of this colloquium addressed the following issues: the role of new energy technologies in the French and World sustainable development; The programmes 'New energy technologies'; Research priorities for these new technologies; Industry Perspectives and challenges; SMEs and the ANR; Research perspectives and challenges (electrochemical storage of energy, solar photovoltaic energy, new materials for energy, integration of renewable energies in electric systems, technological innovations for new energy technologies)

  14. [Clinical and biological effectiveness of antiretroviral therapy in the ANRS 1215 cohort].

    Science.gov (United States)

    De Beaudrap, P; Diouf, A; Bousso Niang, K

    2014-10-01

    In 1998, the cohort ANRS 1215 was launched in Senegal with one of the first African antiretroviral treatment programs. Four hundred forty four HIV-infected adults started on ART were included between 1998 and 2004, and followed up to 2010. Mortality before 6 months was 15.6/100 person-year (PY) and associated to the initial disease severity. It decreased to 3.36/100 PY thereafter. The cumulative risks of virologic failure at 60 months and of drug resistance at 48 months were 25% and 16%, respectively. PMID:24619515

  15. μ +-SR studies of the weak ferromagnets CoCO 3 and NiCO 3

    Science.gov (United States)

    Lancaster, T.; Blundell, S. J.; Pratt, F. L.; Kurmoo, M.

    2003-02-01

    We present the results of zero-field μ +-SR measurements on CoCO 3 and NiCO 3. Both compounds are rhombohedral antiferromagnets which exhibit a spontaneous weak magnetisation below 22.2 and 17.2 K, respectively. This arises due to an anisotropic superexchange (Dzyaloshinsky-Moriya) interaction. We have studied the temperature dependence of the internal field in the ordered state and the magnetic fluctuations in the paramagnetic state. We describe the possible muon-site obtained from dipolar-field calculations.

  16. La construction d’une économie touristique sur la côte aquitaine sous la Ve république (1958-1988)

    OpenAIRE

    Noailles, Mikael

    2016-01-01

    Longtemps réservé à une élite, le tourisme connaît un développement spectaculaire en Aquitaine après la Seconde Guerre mondiale. Il faut donc étudier comment par la démocratisation et la massification, le tourisme est passé de la marge au cœur du système socio-économique et politique aquitain. Cette longue période de profonds changements se traduit par l’organisation du secteur touristique à travers un réseau d’acteurs diversifié, par des mutations dans les pratiques touristiques. Le tourisme...

  17. 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.

  18. ANR Corpus architecturae religiosae europeae [CARE]saec. IV-X

    Directory of Open Access Journals (Sweden)

    Christian Sapin

    2010-10-01

    Full Text Available Le projet ANR «Corpus des monuments religieux antérieurs à l’an Mil» [Corpus architecturae religiosae europeae/CARE – IV-X saec.] a débuté en janvier 2008. Il représente l’apport de la France à un programme international, initié en 2002 par l’IRCLAMA de Zagreb (Croatie . Ce corpus a pour objectif de recenser les édifices religieux d’Europe entre le IVe siècle et le tout début du XIe siècle. Il regroupe déjà l’Italie, l’Espagne, la Croatie, l’Europe centrale et demain, probablement, l’Irlande...

  19. Gravity anomalies, spatial variation of flexural rigidity, and role of inherited crustal structure in the Aquitaine Basin

    Science.gov (United States)

    Angrand, Paul; Ford, Mary; Watts, Anthony; Bell, Rebecca E.

    2016-04-01

    The Aquitaine foreland basin developed from Campanian to Miocene by flexure of the upper (European) plate during the Pyrenean orogeny. The foreland basin forms a syn-orogenic sedimentary wedge up to 6 km thick in the south, thinning rapidly north and has a maximum width of 200 km in the west. The flexural basin was superimposed on a lithosphere previously affected by Apto-Albian hyper-extension. What are the effects of an inherited extremely weak and narrow rifted zone on the behavior of a superimposed flexural foreland basin? Coupled with surface and subsurface data, Bouguer gravity anomalies were used to determine the crustal structure of the northern Pyrenean retrowedge and the flexure of the European plate. In the centre, the basin shows a regional Bouguer anomaly pattern typical of foreland basins with the maximum of syn-orogenic deposits corresponding to a low and the forebulge to a high. However, south of the North Pyrenean Frontal Thrust (NPFT) this regional field is overprinted by strong positive Bouguer anomalies, which correspond to high density bodies (mantle or lower crust) transported along the NPFT. Stratigraphy shows that the central basin evolved as a series of narrow, laterally variable depocentres that migrated north. Shortening is accommodated mainly by thick skinned deformation and local reactivation of salt structures. In the east, the Toulouse Fault separates the central and eastern foreland. The eastern foreland shows a broader zone of negative Bouguer values. This foreland is salt-free and stratigraphy records higher subsidence. The easternmost basin is completely overprinted by the opening of the Gulf of Lion. In the west, the foreland does not show a typical regional gravity anomaly pattern due to overprinting by the opening of the Bay of Biscay. Instead, a major gravity high is centered on the northern Landes High, with a second high centered on the Labourd massif south of the NPFT. Neither the Parentis rift basin nor the salt

  20. The system MgCO3-FeCO3-CaCO3-Na2CO3 at 12-23 GPa: Phase relations and significance for the genesis of ultradeep diamonds

    Science.gov (United States)

    Spivak, A. V.; Solopova, N. A.; Dubrovinsky, L. S.; Litvin, Yu. A.

    2015-09-01

    Physical-chemical experimental studies at 12-23 GPa of phase relationships within four-members carbonate system MgCO3-FeCO3-CaCO3-Na2CO3 and its marginal system MgCO3-FeCO3-Na2CO3 were carried out. The systems are quite representative for a set of carbonate phases from inclusions in diamonds within transitional zone and lower mantle. PT-phase diagrams of multicomponent carbonate systems are suggested. PT parameters of boundaries of their eutectic melting (solidus), complete melting (liquids) are established. These boundaries define area of partial melting. Carbonate melts are stable, completely mixable, and effective solvents of elemental carbon thus defining the possibility of ultra-deep diamonds generation.

  1. Drug use in prisons: strategies for harm reduction (ANRS-PRIDE Program

    Directory of Open Access Journals (Sweden)

    Laurent Michel

    2016-07-01

    Full Text Available Abstract The existence of risky practices related to drug use inside prisons is a reality everywhere and is a major issue for the community as a whole. The level of implementation of harm reduction (HR measures recommended by the World Health Organization (WHO and the United Nations Office on Drugs and Crime (UNODC is very often poor and reveals inadequate concern about public health issues in the prison environment, without any respect for the principle of equivalence for prevention and health assistance with the general community. In 2009, the French National Agency for Research on AIDS and Viral Hepatitis (ANRS developed a comprehensive research program focusing on the prevention of infectious risks in prison settings. Different steps were defined and scheduled, and included i an inventory of harm reduction (HR measures, ii a qualitative survey on the reality of risky practices, iii an assessment of the social acceptability of HR measures, and iv an intervention trial exploring the feasibility of upgrading existing HR strategies. A progressive implementation of this program has shown it is feasible, but in France, it requires tenacity, simple long-term objectives, support from a scientific authority, pedagogical interventions for all involved, as well as constant discussion with the authorities. The implementation of this program in other countries is equally simple to manage.

  2. 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.

  3. Drug use in prisons: strategies for harm reduction (ANRS-PRIDE Program).

    Science.gov (United States)

    Michel, Laurent

    2016-06-01

    The existence of risky practices related to drug use inside prisons is a reality everywhere and is a major issue for the community as a whole. The level of implementation of harm reduction (HR) measures recommended by the World Health Organization (WHO) and the United Nations Office on Drugs and Crime (UNODC) is very often poor and reveals inadequate concern about public health issues in the prison environment, without any respect for the principle of equivalence for prevention and health assistance with the general community. In 2009, the French National Agency for Research on AIDS and Viral Hepatitis (ANRS) developed a comprehensive research program focusing on the prevention of infectious risks in prison settings. Different steps were defined and scheduled, and included i) an inventory of harm reduction (HR) measures, ii) a qualitative survey on the reality of risky practices, iii) an assessment of the social acceptability of HR measures, and iv) an intervention trial exploring the feasibility of upgrading existing HR strategies. A progressive implementation of this program has shown it is feasible, but in France, it requires tenacity, simple long-term objectives, support from a scientific authority, pedagogical interventions for all involved, as well as constant discussion with the authorities. The implementation of this program in other countries is equally simple to manage. PMID:27383342

  4. 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 sche...

  5. Magnetic compressor studies for F.E.L. applications at the Centre D'Etudes Scientifiques et Techniques D'Aquitaine

    International Nuclear Information System (INIS)

    A F.E.L. (Free Electron Laser) program based on a linear induction accelerator (LINAC) is currently being developed at CESTA (Aquitaine Center of Scientific and Technical Research). This technology requires the development of high power electric pulse generators (150 kV - 2 Ω) able to work at high repetition rates (≥ 1 kHz). Limitations of conventional power components (solid-state circuit, high pressure gas blown switches, hor-ellipsis) have led the authors to design pulse generators using magnetic switches. A prototype has been built and different magnetic cores were tested in single-shot mode

  6. 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.

  7. Melting relations of multicomponent carbonate MgCO3-FeCO3-CaCO3-Na2CO3 system at 12-26 GPa: application to deeper mantle diamond formation

    Science.gov (United States)

    Spivak, Anna; Solopova, Natalia; Dubrovinsky, Leonid; Litvin, Yuriy

    2015-11-01

    Carbonatic components of parental melts of the deeper mantle diamonds are inferred from their primary inclusions of (Mg, Fe, Ca, Na)-carbonate minerals trapped at PT conditions of the Earth's transition zone and lower mantle. PT phase diagrams of MgCO3-FeCO3-CaCO3-Na2CO3 system and its ternary MgCO3-FeCO3-Na2CO3 boundary join were studied at pressures between 12 and 24 GPa and high temperatures. Experimental data point to eutectic solidus phase relations and indicate liquidus boundaries for completely miscible (Mg, Fe, Ca, Na)- and (Mg, Fe, Ca)-carbonate melts. PT fields for partial carbonate melts associated with (Mg, Fe)-, (Ca, Fe, Na)-, and (Na2Ca, Na2Fe)-carbonate solid solution phases are determined. Effective nucleation and mass crystallization of deeper mantle diamonds are realized in multicomponent (Mg, Fe, Ca, Na)-carbonatite-carbon melts at 18 and 26 GPa. The multicomponent carbonate systems were melted at temperatures that are lower than the geothermal ones. This gives an evidence for generation of diamond-parental carbonatite melts and formation of diamonds at the PT conditions of transition zone and lower mantle.

  8. 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.

  9. Patrimonialisation/The making of Heritage/Présentation Axe thématique projet ANR AQAPA

    OpenAIRE

    David, Béatrice

    2014-01-01

    Atelier de lancement projet ANR/AQAPA 28, 29, 30 avril 2014. Présentation des axes thématiques : Béatrice David (LAVUE-AUS, Université Paris-8) Patrimonialisation (« mise en patrimoine)/ The making of heritage/ Heritagization The study of Heritage making has become in the last 20 years a legitimate "object" in social sciences, notably in anthropology, then by geographic studies which have largely invested the field, particularly in exploring the intimate link between Territory and Heritage. T...

  10. 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.

  11. Alternative solution model for the ternary carbonate system CaCO3 - MgCO3 - FeCO3 - I. A ternary Bragg-Williams ordering model

    Science.gov (United States)

    McSwiggen, P.L.

    1993-01-01

    The minerals of the ternary carbonate system CaCO3 - MgCO3 - FeCO3 represent a complex series of solid solutions and ordering states. An understanding of those complexities requires a solution model that can both duplicate the subsolidus phase relationships and generate correct values for the activities. Such a solution model must account for the changes in the total energy of the system resulting from a change in the ordering state of the individual constituents. Various ordering models have been applied to binary carbonate systems, but no attempts have previously been made to model the ordering in the ternary system. This study derives a new set of equations that allow for the equilibrium degree of order to be calculated for a system involving three cations mixing on two sites, as in the case of the ternary carbonates. The method is based on the Bragg-Williams approach. From the degree of order, the mole fractions of the three cations in each of the two sites can be determined. Once the site occupancies have been established, a Margules-type mixing model can be used to determine the free energy of mixing in the solid solution and therefore the activities of the various components. ?? 1993 Springer-Verlag.

  12. Geothermics in Aquitaine

    International Nuclear Information System (INIS)

    The geothermal exploitation of the Aquitanian Basin (S W France) started 15 years ago and has extended today to 12 different places. Three main aquifers of different depth are exploited in Bordeaux region: the old alluvial deposits of Garonne river (20-30 m), the Middle Eocene aquifer (300-400 m), and the Cenomanian-Turonian aquifer (900-1100 m) which is the deepest and most exploited for geothermal purposes. The drinkable quality of the water and the use of single-well technique are important factors that reduce the operating costs. Geothermics remains competitive with other energy sources due to the long-term stability of geothermal energy costs. (J.S.). 2 figs., 1 tab., 5 photos

  13. [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.

  14. The decarbonation and heat capacity of ZnCO3

    Science.gov (United States)

    Haselton, H.T.; Goldsmith, J.R.

    1987-01-01

    The decarbonation curve for ZnCO3 has been determined in the pressure range 3-20 kbar by using a combination of cold-seal vessels and piston-cylinder apparatus with NaCl assemblies. Heat capacities for both synthetic and natural ZnCO3 samples were measured by differential scanning calorimetry at temperatures ranging from 340 to 497 K. The results of these experiments indicate that the enthalpy of formation for smithsonite, ??Hf(1,298.15), is approximately -817. kJ/mol. which is about 4 kJ more negative than most tabulated values. ?? 1987.

  15. The solubility of rhodochrosite (MnCO3) and siderite (FeCO3) in anaerobic aquatic environments

    DEFF Research Database (Denmark)

    Jensen, Dorthe Lærke; Boddum, J.K.; Tjell, Jens Christian;

    2002-01-01

    Natural groundwaters are often reported to be highly supersaturated with the carbonate minerals siderite (FeCO3) and rhodochrosite (MnCO3). The kinetics of precipitation and dissolution were determined in the light of new determinations of the solubility products of siderite and rhodochrosite....... Laboratory experiments showed that the precipitation kinetics of siderite and rhodochrosite were much slower than that of calcite, and also much slower than their dissolution kinetics. Experiments with supersaturated solutions failed to reach steady state within 474 days in the case of siderite, whereas...... steady state for rhodochrosite was reached after 140 days. Suspensions of siderite and rhodochrosite crystals reached steady state after 10 and 80 days, respectively. The solubility product of siderite (log KS0(FeCO3)) was 11.03 0.10 for dried crystals and 10.43 0.15 for wet crystals. For rhodochrosite...

  16. 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。

  17. 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.

  18. 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.

  19. Magnetic Co3O4 nanowires,preparation and properties

    Institute of Scientific and Technical Information of China (English)

    Mai Xia Ma; Wei Meng Chen; Lin Guo; Jing Hong Li; Chin Ping Chen; Shi He Yang

    2012-01-01

    The Co3O4 nanowires have been successfully synthesized via modified template method.The as-prepared products have been characterized by EDS,TEM and HRTEM analysis.The magnetic behavior of it is investigated by a magnetic property measurement system.The nanowires exhibit some novel magnetic properties,which are different from its bulk material.The temperature dependence curves of magnetization in zero-field-cooling and field-cooling exhibit two peaks of antiferromagnetic at blocking temperature of ~23 K and ~31 K,respectively.The field dependent M(H) curves of the Co3O4 nanowires at T =5 and 300 K both exhibit PM properties.Moreover,the diameter of nanowires is hence determined according to the finite size effect as approximately 7-11 nm,in consistent with the characterizations by HRTEM.

  20. Synthesis and photocatalytic property of multilayered Co3O4

    Science.gov (United States)

    Zhang, Dong En; Ren, Li Zheng; Hao, Xiao Yun; Pan, Bin Bin; Wang, Ming Yan; Ma, Juan Juan; Li, Feng; Li, Shu An; Tong, Zhi Wei

    2015-11-01

    Co3O4 multilayered structures were successfully synthesized by a facile poly (ethylene glycol 20000) (PEG-20000) assisted hydrothermal technique in combination with calcination method. The final Co3O4 multilayered structures inherited perfectly the morphology of the preliminarily hydrothermal products. Experimental results obtained from the different growth stages demonstrate that the as-prepared precursor exhibit an interesting time-dependent evolution of building blocks, from urchin to multilayer. The possible formation mechanism for the hierarchical structures with various architectures is presented on account of the self-assembled growth induced by Ostwald ripening. Because of the unique structured composed of slices, the photocatalytic activity of the products was examined by measuring the photodecolourisation of methyl violet solution with ultraviolet radiation. The result shows that our products have a good photocatalytic activity.

  1. 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.

  2. PP/CaCO3复合体系力学性能研究%Mechanical Properties of PP/CaCO3 Composite

    Institute of Scientific and Technical Information of China (English)

    高蕊; 王燕; 裴现勇

    2004-01-01

    改变CaCO3含量、CaCO3种类、偶联剂用量、CaCO3与滑石粉的配比等,对PP/CaCO3复合材料力学性能进行了研究与分析.结果表明:CaCO3用量、种类及滑石粉和偶联剂用量均对体系力学性能有影响.

  3. 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.

  4. 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

    OpenAIRE

    Mélanie Plazy; Kamal El Farouki; Collins Iwuji; Nonhlanhla Okesola; Joanna Orne-Gliemann; Joseph Larmarange; France Lert; Marie-Louise Newell; François Dabis; Rosemary Dray-Spira

    2016-01-01

    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 ...

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Community perceptions of repeat HIV-testing: experiences of the ANRS 12249 Treatment as Prevention trial in rural South Africa.

    Science.gov (United States)

    Orne-Gliemann, Joanna; Zuma, Thembelihle; Chikovore, Jeremiah; Gillespie, Natasha; Grant, Merridy; Iwuji, Collins; Larmarange, Joseph; McGrath, Nuala; Lert, France; Imrie, John

    2016-01-01

    In the context of the ANRS 12249 Treatment as Prevention (TasP) trial, we investigated perceptions of regular and repeat HIV-testing in rural KwaZulu-Natal (South Africa), an area of very high HIV prevalence and incidence. We conducted two qualitative studies, before (2010) and during the early implementation stages of the trial (2013-2014), to appreciate the evolution in community perceptions of repeat HIV-testing over this period of rapid changes in HIV-testing and treatment approaches. Repeated focus group discussions were organized with young adults, older adults and mixed groups. Repeat and regular HIV-testing was overall well perceived before, and well received during, trial implementation. Yet community members were not able to articulate reasons why people might want to test regularly or repeatedly, apart from individual sexual risk-taking. Repeat home-based HIV-testing was considered as feasible and convenient, and described as more acceptable than clinic-based HIV-testing, mostly because of privacy and confidentiality. However, socially regulated discourses around appropriate sexual behaviour and perceptions of stigma and prejudice regarding HIV and sexual risk-taking were consistently reported. This study suggests several avenues to improve HIV-testing acceptability, including implementing diverse and personalised approaches to HIV-testing and care, and providing opportunities for antiretroviral therapy initiation and care at home. PMID:27421048

  10. TOUGHENING AND STRENGTHENING OF PP WITH NANO-CaCO3%纳米CaCO3增韧增强PP研究

    Institute of Scientific and Technical Information of China (English)

    胡圣飞; 郦华兴; 严海彪

    2004-01-01

    研究了纳米及微米CaCO3对聚丙烯(PP)力学性能的影响,探讨了纳米CaCO3增韧增强PP的机理,并用扫描电子显微镜及差示扫描量热仪对改性PP进行观察与分析.结果表明,纳米CaCO3改性PP的力学性能优于微米CaCO3改性PP;纳米CaCO3用量为10~12份时,改性PP综合性能较好;纳米CaCO3改性PP力学性能的提高可用"开关模型"解释并与β晶的形成有关.

  11. CaCO3 Precipitation Potential and Its Application%CaCO3沉淀势指数及其应用

    Institute of Scientific and Technical Information of China (English)

    韩虹琳

    1998-01-01

    灰水系统结垢主要为CaCO3垢,对水中结CaCO3垢倾向的判断,方法很多,但准确性较差.根据实测CaCO3沉淀势指数判断结垢倾向、衡量结垢程度方便、准确、可靠、经济.

  12. 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.

  13. Electronic, optical and bonding properties of MgCO 3

    Science.gov (United States)

    Hossain, Faruque M.; Dlugogorski, B. Z.; Kennedy, E. M.; Belova, I. V.; Murch, Graeme E.

    2010-05-01

    The electronic, optical and bonding properties of MgCO 3 (magnesite, rhombohedral calcite-type structure) are calculated using a first-principles density-functional theory (DFT) method considering the exchange-correlation function within the local density approximation (LDA) and the generalized gradient approximation (GGA). The indirect band gap of magnesite is estimated to be 5.0 eV, which is underestimated by ˜1.0 eV. The fundamental absorption edge, which indicates the exact optical transitions from occupied valence bands to the unoccupied conduction band, is estimated by calculating the photon energy dependent imaginary part of the dielectric function using scissors approximations (rigid shift of unoccupied bands). The optical properties show consistent results with the experimental calcite-type structure and also show a considerable optical anisotropy of the magnesite structure. The density of states and Mulliken population analyses reveal the bonding nature between the atoms.

  14. 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.

  15. 纳米CaCO3表面有机化处理%Organic modification of nano-CaCO3 surface

    Institute of Scientific and Technical Information of China (English)

    张桂霞; 刘国军

    2006-01-01

    采用水性体系对纳米CaCO3进行表面处理.XPS、FT-IR、TGA分析表明,硅烷偶联剂KH-570能与纳米CaCO3生成SiOCa键,从而化学健接到CaCO3粒子表面.TEM分析表明,改性后的纳米CaCO3能有效地以初始粒子结构进行分散.

  16. Effect of Morphology of Co3O4 for Oxygen Evolution Reaction in Alkaline Water Electrolysis

    OpenAIRE

    Xu, Qi-Zhi; Su, Yu-Zhi; Wu, Hao; Cheng, Hui; Hui, Yun-Ping; Li, Nan; Liu, Zhao-Qing

    2014-01-01

    In this paper, three different morphological Co3O4 electrodes for oxygen evolution reaction (OER) have been synthesized. By comparing the three morphologies of Co3O4, the electrocatalytic properties show that the urchin-like spheres of Co3O4 electrode has relative low overpotential and good electrocatalysis stability, indicating that the structure of urchin-like Co3O4 spheres exhibit an easy OER for water splitting.

  17. 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%.

  18. 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...

  19. Etude préliminaire pour l’évaluation et le suivi du niveau de qualité des viandes bovines Label Rouge d’Aquitaine, par une méthode simplifiée alternative à celle du comité français d’accréditation (COFRAC)

    OpenAIRE

    Ellies-Oury, Marie-Pierre; Dauvergne, Arlette; Papillon, Sandrine; Jacob, Hervé; Picard, Brigitte; Micol, Didier

    2014-01-01

    Les Organismes de Défense et de Gestion (ODG) ont la possibilité d’utiliser une méthode alternative au programme 133 du COFRAC pour prouver la supériorité sensorielle des produits Label Rouge (LR). En Aquitaine, il existe 4 LR en viande bovine : Boeuf Blond d’Aquitain, Boeuf Excellence, Boeuf de Chalosse et Boeuf de nos Campagnes. Dans un premier temps, un jury de 16 personnes qualifiées représentant les différents maillons de chacune des filières (éleveurs, abatteurs, chevillards...

  20. CaCO3粉末表面光聚合处理的研究%Photo Polymerization of Acrylamide onto CaCO3 Particle Surfaces

    Institute of Scientific and Technical Information of China (English)

    雷景新; 何光健; 高峻

    2004-01-01

    采用表面光聚合技术处理CaCO3粉末,研究了反应温度、时间、单体浓度等对丙烯酰胺(AAM)在CaCO3粉末表面光聚合的影响,并采用X光电子能谱(ESCA)、粒度分析、扫描电子显微镜(SEM)和模型模拟分析等研究了表面光聚合处理碳酸钙(CaCO3)的结构.结果表明:紫外光能有效地引发AAM在CaCO3粒子表面聚合.经光聚合处理后,CaCO3粒子表面形成了聚丙烯酰胺(PAAM)包覆层,该包覆层与CaCO3粒子结合紧密,不能被溶剂洗涤清除.光聚合处理后CaCO3粒子表面较光滑,分散性可得到提高,CaCO3粒子粒径增大.

  1. STUDY ON DIFFERENT SHAPE NANO-CaCO3 MODIFYING PP%不同形态纳米级CaCO3改性PP研究

    Institute of Scientific and Technical Information of China (English)

    胡圣飞; 郦华兴; 严海彪

    2004-01-01

    研究了不同形态纳米级CaCO3改性PP复合材料的力学性能及其对PP球晶形态的影响.结果表明,纳米级CaCO3形态不同,复合材料力学性能不一样,立方形纳米级CaCO3有利于改善复合材料的冲击性能,而纤维状纳米级CaCO3则能明显改善材料的拉伸性能.纳米级CaCO3能使PP球晶明显的细化,并能促进β晶型的生成.

  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. Crystal structure and magnetic properties of the Ba3TeCo3P2O14, Pb3TeCo3P2O14, and Pb3TeCo3V2O14 langasites

    DEFF Research Database (Denmark)

    Krizan, J.W.; de la Cruz, C.; Andersen, Niels Hessel;

    2013-01-01

    We report the structural and magnetic characterizations of Ba3TeCo3P2O14, Pb3TeCo3P2O14, and Pb3TeCo3V2O14, compounds that are based on the mineral dugganite, which is isostructural to langasites. The magnetic part of the structure consists of layers of Co2+ triangles. Nuclear and magnetic...... of the three compounds studied along with the zinc analog Pb3TeZn3P2O14, also characterized here, suggests that the distortion is driven by Pb2+ lone pairs; as such, the Pb compounds crystallize in a pyroelectric space group, P2. Magnetic susceptibility, magnetization, and heat capacity measurements were...... performed to characterize the magnetic behavior. All three compounds become antiferromagnetic with Néel temperatures TN≈21K (Ba3TeCo3P2O14), ≈13K (Pb3TeCo3P2O14), and ≈8K (Pb3TeCo3V2O14), and they exhibit magnetic transitions at high applied magnetic fields, suggesting intrinsically complex magnetic...

  4. 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.

  5. THE CaCO3 IN LOESS AND ITS RELATION TO ENVIRONMENT%黄土中的CaCO3与环境

    Institute of Scientific and Technical Information of China (English)

    李秉成

    2002-01-01

    提出了黄土中CaCO3对环境的意义,重点阐述了黄土地层中CaCO3来源、含量等问题,对陕西西安刘家坡、兰州等地黄土进行了分析和研究,从而揭示了黄土中CaCO3含量与气候环境的密切关系.

  6. CaCO3对PE/CaCO3共混体系力学性能影响的研究

    Institute of Scientific and Technical Information of China (English)

    李春艳; 董金虎

    2009-01-01

    本文以PE/CaCO3共混体系为研究对象,探讨随CaCO3含量的逐步改变,共混体系弹性模量、断裂伸长率、冲击强度等力学性能的变化趋势,并分析了产生这些变化趋势的原因,获得了较为理想的PE/CaCO3组分配比.

  7. Hydrocalcite (CaCO3 * H2O) and Nesquehonite (MgCO3 * 3H2O) in Carbonate Scales.

    Science.gov (United States)

    Marschner, H

    1969-09-12

    Hydrocalcite (CaCO(3) * H(2)O) with exactly one molecule of hydrate water is the main component of carbonate scales deposited from cold water in contact with air. When the magnesium content of the water is high, the hydrocalcite occurs together with MgCO(3) * 3H(2)O (nesquehonite). From the conditions under which hydrocalcite is transformed into calcite and aragonite, it appears that in some cases aragonite in nature may be formed by way of an intermediary of CaCO(3) * H(2)O. PMID:17779803

  8. Crystallinity, magnetic and electrochemical studies of PVDF/Co3O4 polymer electrolyte

    International Nuclear Information System (INIS)

    Highlights: ► PVDF–Co3O4 nanocomposite films are prepared by spin coating method. ► Porosity and crystallinity of the films are discussed. ► Magnetic properties of the films are studied. ► Presence of Co3O4 in PVDF enhanced its conductivity. - Abstract: Organic–inorganic nanocomposites are gaining importance in the recent times as polymer electrolyte membranes. In the present work, composites were prepared by combining nano sized Co3O4 and poly(vinyledene fluoride) (PVDF), using spin coating technique. The surface of the PVDF/Co3O4 system characterized through field emission scanning electron microscopy (FESEM) revealed a porous structure of the films. The nanoparticles tend to aggregate on the surface and inside the pores, leading to a decrease in the porosity with an increase in Co3O4 content. Co3O4 nanoparticles prohibit crystallization of the polymer. Differential scanning calorimetry (DSC) studies revealed a decrease in crystallinity of PVDF/Co3O4 system with an increase in the oxide content. Magnetic property studies of the composite films revealed that with an increase in Co3O4 content, the saturation magnetization values of the nanocomposites increased linearly, showing successful incorporation of the nanoparticles in the polymer matrix. Further, ionic conductivity of the composite films was evaluated from electrochemical impedance spectroscopy. Addition of Co3O4 nanoparticles enhanced the conductivity of PVDF/Co3O4 system.

  9. 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

  10. Uptake of PrEP and condom and sexual risk behavior among MSM during the ANRS IPERGAY trial.

    Science.gov (United States)

    Sagaon-Teyssier, Luis; Suzan-Monti, Marie; Demoulin, Baptiste; Capitant, Catherine; Lorente, Nicolas; Préau, Marie; Mora, Marion; Rojas Castro, Daniela; Chidiac, Christian; Chas, Julie; Meyer, Laurence; Molina, Jean-Michel; Spire, Bruno

    2016-01-01

    The double-blind phase of the randomized ANRS IPERGAY trial, evaluating sexual activity-based oral HIV pre-exposure prophylaxis (PrEP), was conducted among high-risk men who have sex with men (MSM). Results showed an 86% (95% CI: 40-98) relative reduction in HIV incidence among participants with tenofovir disoproxil fumarate-emtricitabine vs. placebo. The present pooled analysis aimed to analyze (i) participants' adherence to the prescribed treatment and/or condom use during sexual intercourse and (ii) sexual behavior during the double-blind phase of the study. Four hundred MSM were enrolled in the trial. Every 2 months they completed online questionnaires collecting sexual behavior and PrEP adherence data regarding their most recent sexual intercourse. A total of 2232 questionnaires (M0-M24) were analyzed. Changes over time were evaluated using a mixed model accounting for multiple measures. Irrespective of sexual partner and practice type, on average, 42.6% (min: 32.1-max: 45.8%) reported PrEP use only during their most recent episode of sexual intercourse; 29% (22.9-35.6%) reported both PrEP and condom use; 11.7% (7.2-18.9%) reported condom-use only, and 16.7% (10.8-29.6%) reported no PrEP or condom use with no significant change during the study. Scheduled (i.e., correct) PrEP use was reported on average by 59.0% (47.2-68.5%) of those reporting PrEP use during their most recent sexual intercourse. Overall, 70.3% (65.3-79.4%) and 69.3% (58.3-75.4%) of participants reported, respectively, condomless anal and condomless receptive anal intercourse during their most recent sexual encounter without significant change during follow-up. Overall, on average 83.3% (min: 70.4-max: 89.2%) of participants protected themselves by PrEP intake or condom use or both during the trial, and no increase in at-risk sexual practices was observed. None of these indicators showed significant trend during the follow-up, although we found a tendency toward decrease (p = .19) of the

  11. In Situ Investigations into CaCO3 Nucleation

    Science.gov (United States)

    Nielsen, Michael Harold

    predictions of classical nucleation theory to this system. Low resolution microscopy techniques are further used to provide indirect evidence for the formation pathways of calcite on SAMs exhibiting different surface chemistries. The development of a platform for liquid phase transmission electron microscopy (TEM) utilizing a sealed liquid cell is described, and its utility in making novel observations of materials formation processes is demonstrated. Liquid phase TEM is further employed, using an open cell system which allows for mixing reagents, to directly observe formation pathways in the CaCO3 system.

  12. 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.

  13. 超微细CaCO3结晶的控制生长%Growth Control of Ultrafine CaCO3

    Institute of Scientific and Technical Information of China (English)

    林荣毅; 张家芸; 张培新

    2001-01-01

    通过SEM显微技术,从亚微观结构研究Na5P3O10对Ca(OH)2碳化反应中CaCO3结晶的控制生长过程.结果表明,CaCO3结晶的成核、生长在时间上是重叠的伴随过程.在CaCO3反应结晶的起始阶段,Na5P3O10的存在促进了CaCO3的大量成核.通过SEM可以观测到大量亚稳态CaCO3籽晶(R=23~26nm)的存在.这时,CaCO3晶体生长并不符合Zener-Ham理论的扩散生长规律.结晶生长由穿越晶体界面的短程扩散控制.在反应结晶末期,SEM已观测不到亚稳态CaCO3籽晶的存在.CaCO3结晶生长遵循长程扩散控制模型R(t)=λi(Dt)n,时间指数n=0.4874~0.4992(理论值n=0.5).随着碳化液中Na5P3O10浓度的增大,常数λiDn由16.69降低至11.36,从而有效地控制CaCO3的结晶生长.%The ultrafine CaCO3 crystal growth controlled by Na5P3O10 in the carbonation of Ca(OH)2 suspension,was investigated by using SEM. The results show that CaCO3 nucleates along with the nucleus growth. The presence of Na5P3O10 accelerates the CaCO3 nucleation. At the initial stage,a large number of CaCO3 nucleus engender,and metastable tiny crystallites (R=2326nm) can be observed in SEM imagine. The CaCO3 crystal growth controlled by short distance diffusion when mass pass through the crystal interface,does not correspond to Zener-Ham theory. At the next stage,the metastable tiny crystallites disappear in SEM imagine. The CaCO3 crystal growth abides by the long distance control model R(t)=λi(Dt)n,in which the time coefficient n is 0.4874~0.4992 (theory value n=0.5) and the constant λiDn decreases from 16.69 to 11.36. Consequently,Na5P3O10 can effectively inhabit the CaCO3 crystal growth.

  14. 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. PMID:26738558

  15. High-temperature heat capacity of Co3O4 spinel: thermally induced spin unpairing transition

    Science.gov (United States)

    Mocala, K.; Navrotsky, A.; Sherman, David M.

    1992-01-01

    A strong anomaly was found in the heat capacity of Co3O4 between 1000 K and the decomposition temperature. This anomaly is not related to the decomposition of Co3O4 to CoO. The measured entropy of transition, ??S=46??4 J mol-1 K-1 of Co3O4, supports the interpretation that this anomaly reflects a spin unpairing transition in octahedrally coordinated Co3+ cations. Experimental values of heat capacity, heat content and entropy of Co3O4 in the high temperature region are provided. The enthalpy of the spin unpairing transition is 53??4 kJ mol-1 of Co3O4. ?? 1992 Springer-Verlag.

  16. Nucleation kinetics of nesquehonite (MgCO 3·3H 2O) in the MgCl 2-Na 2CO 3 system

    Science.gov (United States)

    Cheng, Wenting; Li, Zhibao

    2010-04-01

    The nucleation of nesquehonite (MgCO 3·3H 2O) in MgCl 2-Na 2CO 3 system with and without the addition of NaCl was studied within a supersaturation range of 1.06-1.48 at 288.15-308.15 K. The supersaturation ( S) of MgCO 3·3H 2O was exactly calculated by aqueous (H + ion) model through OLI platform. The conductivity method was applied in this experiment to determine the induction period of MgCO 3·3H 2O. The effects of temperature, supersaturation, and presence of additive (NaCl) on the induction period of MgCO 3·3H 2O were studied experimentally. As expected from theory, it was found that the induction period decreases when either temperature or supersaturation increases. The induction period was prolonged by adding NaCl in solutions at a constant supersaturation. From the dependence of the induction period on temperature and supersaturation, it was possible to distinguish between the homogeneous and heterogeneous nucleation mechanisms. At last, the activation energy ( Eact) for MgCO 3·3H 2O crystallization and the interfacial tension between MgCO 3·3H 2O and aqueous solutions of homogeneous ( γS,hom) and heterogeneous ( γS,het) nucleation were calculated from measurements of the induction period for the MgCO 3·3H 2O nucleation with and without the addition of NaCl.

  17. Heat capacities and entropies of rhodochrosite (MnCO3) and siderite (FeCO3) between 5 and 600 K.

    Science.gov (United States)

    Robie, R.A.; Haselton, H.T., Jr.; Hemingway, B.S.

    1984-01-01

    The heat capacities of rhodochrosite, (Mn0.994Fe0.005Mg0.001)CO3, and siderite, 171(Fe0.956Mn0.042Mg0.002)CO3, were measured between 5 and 550 K by combined cryogenic-adiabatic and differential scanning calorimetry. These new data were used to reanalyse the thermodynamic properties of these phases.-J.A.Z.

  18. 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.

  19. Carbon nanotube/Co3O4 composite for air electrode of lithium-air battery

    OpenAIRE

    Yoon, Taek Han; Park, Yong Joon

    2012-01-01

    A carbon nanotube [CNT]/Co3O4 composite is introduced as a catalyst for the air electrode of lithium-air [Li/air] batteries. Co3O4 nanoparticles are successfully attached to the sidewall of the CNT by a hydrothermal method. A high discharge capacity and a low overvoltage indicate that the CNT/Co3O4 composite is a very promising catalyst for the air electrode of Li/air batteries.

  20. Uniaxial magnetic anisotropy of rhombohedral CoCO3 crystals at T = 0 K

    Science.gov (United States)

    Men'shikov, V. V.; Rudenko, V. V.; Tugarinov, V. I.; Vorotynov, A. M.; Ovchinnikov, S. G.

    2014-03-01

    A method for calculating the contribution of exchange interaction to uniaxial anisotropy with the use of g' factors has been worked out using CoCO3 crystals as an example. The calculated contribution of dipole-dipole interactions to the anisotropy of CoCO3 is 0.93 cm-1. The sum of the contributions to the anisotropy constant of CoCO3 with the inclusion of the dipole-dipole interactions is 36.1 cm-1.

  1. 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.

  2. Compound Method to Disperse CaCO3 Nanoparticles to Nano-Size in Water.

    Science.gov (United States)

    Gu, Sui; Cai, Jihua; Wang, Jijun; Yuan, Ye; Chang, Dewu; Chikhotkin, Viktor F

    2015-12-01

    The invalidation of CaCO3 nanoparticles (nCaCO3) is often caused by the fact of agglomeration and inhomogeneous dispersion which limits its application into water-based drilling muds for low permeability reservoirs such as coalbed methane reservoir and shale gas/oil reservoir. Effective methods to disperse nCaCO3 to nano-size (≤ 100 nm) in water have seldom been reported. Here we developed a compound method containing mechanical stirring, ultrasonic treatment, the use of surfactant and stabilizer to disperse nCaCO3 in water. It comprises the steps adding 2% nCaCO3, 1% sodium dodecyl sulfonate (SDS), 2% cetyltrimethyl ammonium bromide (CTAB), 2% OP-10, 3% to 4% biopolymer (XC) in water successively, stirring it at a shear rate of 6000 to 8000 r/min for 15 minutes and treating it with ultrasonic at a frequency of 28 KHz for 30 to 40 minutes. The dispersed nCaCO3 was characterized with scanning electron microscope (SEM), transmission electron microscope (TEM) and particle size distribution (PSD) tests. We found that nCaCO3 could be dispersed to below 100 nm in water and the medium value of nCaCO3 was below 50 nm. This method paved the way for the utilization of nCaCO3 in drilling fluid and completion fluid for low permeability reservoirs such as coal seams and shale gas/oil formations. PMID:26682370

  3. Chemical and biological characterization of new Re(CO)3/[99mTc](CO)3 bombesin analogues

    International Nuclear Information System (INIS)

    Introduction: Bombesin, a neuropeptide with potential for breast and prostate tumor targeting, is rapidly metabolized in vivo, and as a result, uptake in tumor xenografts in mice is poor. An improvement can be expected from the introduction of nonnatural amino acids and spacers. Leu13 was replaced by cyclohexylalanine and Met14 by norleucine. Two spacers, -βAla-βAla- and 3,6-dioxa-8-aminooctanoic acid, were inserted between the receptor-binding amino acid sequence (7-14) of bombesin (BBS) and the retroNα-carboxymethyl histidine chelator used for labeling with the [99mTc](CO)3 core and the rhenium (Re) congener. Methods: The biological characterization of the new compounds was performed both in vitro on prostate carcinoma PC-3 cells (binding affinity, internalization/externalization) and in vivo (biodistribution in nude mice with tumor xenografts). The stability was also investigated in human plasma. The Re analogues were prepared for chemical characterization. Results: The nonnatural amino acids led to markedly slower degradation in human plasma and PC-3 cell cultures. The receptor affinity of the new technetium 99m ([99mTc])-labeled BBS analogues was similar to the unmodified compound with K d<1 nM. Uptake in the pancreas and in PC-3 tumor xenografts in nude mice was blocked by unlabeled BBS. The best target-to-nontarget uptake ratio was clearly due to the presence of the more polar spacer, -βAla-βAla-. Conclusions: The different spacers did not have a significant effect on stability or receptor affinity but had a clear influence on the uptake in healthy organs and tumors. Uptake in the kidneys was lower than in the liver, which is likely to be due to the lipophilicity of the compounds. A specific, high uptake was also observed in the gastrin-releasing peptide receptor-rich pancreas. Thus, with the introduction of spacers the in vivo properties of the compounds can be improved while leaving the affinity unaffected

  4. Novel high-pressure structures of MgCO3, CaCO3 and CO2 and their role in Earth's lower mantle

    Science.gov (United States)

    Oganov, Artem R.; Ono, Shigeaki; Ma, Yanming; Glass, Colin W.; Garcia, Alberto

    2008-08-01

    Most of the oxidized carbon in the Earth's lower mantle is believed to be stored in the high-pressure forms of MgCO3 and/or CaCO3 or possibly even CO2. Recently, through ab initio evolutionary simulations and high-pressure experiments, a complete picture of phase transformations of CaCO3 at mantle pressures was obtained. Here, using the same approach, we investigate the high-pressure structures of MgCO3. Two new structure types were predicted to be stable in the relevant pressure range: one at 82-138 GPa and the other above 138 GPa. Both phases contain rings of corner-sharing CO4-tetrahedra. These predictions were largely confirmed by the experiments presented here. A number of structurally very different, but energetically competitive metastable polymorphs were found and reveal complex high-pressure chemistry of MgCO3, in contrast to CaCO3. For CO2, from 19 GPa to at least 150 GPa, we find β-cristobalite structure to be stable. Differences between high-pressure tetrahedral carbonates and low-pressure silicates are discussed in terms of rigidity of the T-O-T angles (flexible when T = Si and stiff when T = C). We show that through most of the P-T conditions of the mantle, MgCO3 is the major host of oxidized carbon in the Earth. We discuss the possibility of CO2 release at the very bottom of the mantle, which could enhance partial melting of rocks and explain the geodynamical differences between the Earth and Venus.

  5. 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...

  6. 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 p...

  7. Controlled precipitation of nesquehonite (MgCO 3·3H 2O) by the reaction of MgCl 2 with (NH 4) 2CO 3

    Science.gov (United States)

    Wang, Yong; Li, Zhibao; Demopoulos, George P.

    2008-03-01

    In this study, homogeneous (unseeded) precipitation of nesquehonite (MgCO 3·3H 2O) by the reaction of MgCl 2 with (NH 4) 2CO 3 in supersaturated solutions was investigated. Factors that influence the precipitation of MgCO 3·3H 2O, such as reaction temperature, initial concentration, stirring speed, titration speed, equilibration time, have been studied. SEM images and particle size distribution show that the temperature, initial concentration and titration speed have significant effect on nesquehonite's crystal morphology and particle size. In addition, stirring speed and equilibration time also have some influence on its properties. X-ray powder diffraction (XRD) results show that the obtained crystals compositions are greatly affected by the reaction temperature. With the morphological transformation, their corresponding composition also change from MgCO 3· xH 2O to Mg 5(CO 3) 4(OH) 2·4H 2O in the interval of 288-333 K. With the optimization of operating conditions, the crystals can grow up to a length of about 40 μm and a width of 5 μm, indicating good filtration properties. High-purity nesquehonite obtained in this study was calcined to produce highly pure MgO at 1073 K as shown by XRD results.

  8. 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.

  9. Effects of PSMA and experimental conditions on the morphologies of BaCO3 whiskers

    Institute of Scientific and Technical Information of China (English)

    CHENG Bei; YU Xiaoxiao; YU Jiaguo; ZHAO Xiujian

    2006-01-01

    BaCO3 whiskers exhibiting different morphologies were fabricated by a simple precipitation reaction of barium chloride with sodium carbonate in the absence and presence of poly-(styrene-alt-maleic acid) (PSMA) as a crystal growth modifier at room temperature. The as-prepared products were characterized by scanning electron microscopy (SEM),transmission electron microscopy (TEM), and X-ray diffraction (XRD). The influences of experimental parameters on the size and morphology of BaCO3 whiskers were investigated and discussed. It was found that the as-prepared BaCO3 whiskers are single crystals with diameter ranging from 100 to 300 nm, and grow along the crystallographic a-axis or [100] direction.BaCO3 whiskers with different morphologies, such as branching and dendritic structure, can be obtained depending on the experimental conditions. With increasing PSMA concentration, the diameter of BaCO3 whiskers decreases.

  10. 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.

  11. CaCO3的表面改性对PP/CaCO3复合材料性能的影响%Effect of Surface Modification of CaCO3 on Mechanical Properties of PP/CaCO3 Composite

    Institute of Scientific and Technical Information of China (English)

    永山; 聪士; 于建; 西 敏夫

    2008-01-01

    采用一步法制备了具有不同界面性质的聚丙烯/碳酸钙(PP/CaCO3)复合体系,考察了界面作用对复合材料性能的影响.结果表明,在只使用CaCO3的情况下,PP/CaCO3复合材料的弯曲强度和热变形温度会提高,但拉伸强度和冲击强度则会有较大程度降低,且CaCO3含量越高对样品的弯曲强度、热变形温度、拉伸强度和冲击强度影响越大;用弹性体包覆CaCO3粒子,不但可以防止PP/CaCO3复合材料的拉伸强度的进一步降低,而且可以提高其冲击强度;加入偶联剂和助偶联剂,有利于弹性体对CaCO3粒子的有效包覆,这种包覆是自发进行的,原子力显微镜结果验证了粒子的核壳结构.

  12. Surface modification of CaCO3 filler and its characterization using inverse gas chromatography (IGC)

    Institute of Scientific and Technical Information of China (English)

    Guangcheng ZHANG; Xuetao SHI; Yajuan XING; Ting CHEN

    2008-01-01

    A CaCO3 filler was treated by generally used coupling agents and a special one-ethylene-octene copolymer (POE)-g-maleic anhydride (MAH). Fourier transform infrared spectroscopy (FTIR) results show that the special coupling agent POE-g-MAH, in a chemical reaction with CaCO3, can produce an interfacial layer stronger than simple physical adhesion attained with usual coupling agents. Inverse gas chromatography (IGC) was used to investigate the surface free energy of CaCO3 after surface modification and to optimize the monolayer content of coupling agents. Based on the IGC results, it can be deduced that the monolayer cover is around 1.9% for CaCO3 treated with a titanate coupling agent. Scanning electron microscope (SEM) observation results show that the separated morphology existed in the ternary composites containing CaCO3 after surface treatment with coupling agents, whereas the core-shell morphology was obtained in the ternary composites with POE-g-MAH. The encapsulation of the CaCO3 filler treated with POE-g-MAH was caused by the strong chemical reaction between the elastomer and CaCO3 particles.

  13. Structural, morphological, optical and magnetic properties of Co3O4 nanoparticles prepared by conventional method

    Science.gov (United States)

    Gopinath, S.; Sivakumar, K.; Karthikeyen, B.; Ragupathi, C.; Sundaram, R.

    2016-07-01

    Cobalt oxide (Co3O4) is one of the favorable nanoparticles (NPs) that possesses many remarkable properties so that it can be used in medicine, chemistry, environment, energy, information, industry, and so on. In this study, the crystalline Co3O4 nanoparticles (NPs) were successfully prepared by an efficient conventional method technique from an using different fuels. In the present paper, pure phase and well-dispersed Co3O4 were synthesized via the starch and aqueous ammonia solution in the stoichiometric fuel compositions. The structure and morphology of by way of organized Co3O4 nanoparticles were characterized by the structural analysis, electron microscopy studies, and optical properties studies. Magnetic properties exposed that the Co3O4 nanoparticles had ferromagnetic performance at room temperature with saturation magnetization of 71.09 emu/g. The results revealed that the changing the precursor led to great effects on the crystal size, emission peaks, and the reaction time of preparing the Co3O4 NPs. The significant feature of this manuscript is that the effects of different precursors on the structural magnetic and optical properties of Co3O4 NPs were investigated for the first time. The average particle size of samples (A and B) 23.6 and 22.2 nm, respectively.

  14. In situ biosynthesis of bacterial nanocellulose-CaCO3 hybrid bionanocomposite: One-step process.

    Science.gov (United States)

    Mohammadkazemi, Faranak; Faria, Marisa; Cordeiro, Nereida

    2016-08-01

    In this work, a simple and green route to the synthesis of the bacterial nanocellulose-calcium carbonate (BNC/CaCO3) hybrid bionanocomposites using one-step in situ biosynthesis was studied. The CaCO3 was incorporated in the bacterial nanocellulose structure during the cellulose biosynthesis by Gluconacetobacter xylinus PTCC 1734 bacteria. Hestrin-Schramm (HS) and Zhou (Z) culture media were used to the hybrid bionanocomposites production and the effect of ethanol addition was investigated. Attenuated total reflection Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, inverse gas chromatography and thermogravimetric analysis were used to characterize the samples. The experimental results demonstrated that the ethanol and culture medium play an important role in the BNC/CaCO3 hybrid bionanocomposites production, structure and properties. The BNC/CaCO3 biosynthesized in Z culture medium revealed higher O/C ratio and amphoteric surface character, which justify the highest CaCO3 content incorporation. The CaCO3 was incorporated into the cellulosic matrix decreasing the bacterial nanocellulose crystallinity. This work reveals the high potential of in situ biosynthesis of BNC/CaCO3 hybrid bionanocomposites and opens a new way to the high value-added applications of bacterial nanocellulose. PMID:27157766

  15. 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.

  16. [Bmim][TfO] ionic liquid-assisted oriented growth of Co3O4 nanoworms

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted Highlights: ► First time, we have used [Bmim][TfO]IL for the synthesis of Co3O4 nanoworms. ► IL assists to form oriented growth of cubic Co3O4 nanoworms without intermediate. ► Cubic Co3O4 nanoworms are in the range of 20 nm width and 100–200 nm length. ► IL and oxidizing agent have not altered the Co3O4 structural characteristics. ► Co3O4 nanoworms exhibit crystalline domain dependent weak ferromagnetism. -- Abstract: Monodispersed worm-like structure of Co3O4 nanocrystals of 20 nm width and 100–200 nm length are prepared directly without any intermediate product by 1-n-butyl-3-methylimidazolium trifluoromethane sulfonate ionic liquid ([Bmim][TfO] IL) assisted precipitation method. The higher concentration of [Bmim][TfO] IL in the reaction medium leads to the formation of homogeneous nanoworms. The effect of synthesis temperature and the oxidizing agent (H2O2) on the Co3O4 particle's morphology and their magnetic properties are discussed. Thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) analysis were used to characterize the Co3O4 monodispersed nanoworms. The magnetic property of the spinel Co3O4 nanoworms is highly dependent on crystalline domains and exhibits weak ferromagnetic behavior with a narrow hysteresis loop opening.

  17. Grain refinement of AZ91D magnesium alloy by MgCO3

    OpenAIRE

    Ti Jun Chen; Xiang Dong Jiang; Ying Ma; Rui Quan Wang; Yuan Hao

    2011-01-01

    The grain refining technique of AZ91D magnesium alloy by MgCO3 has been investigated. The refining mechanism and tensile properties of the resulting alloy have also been discussed. The results indicate that MgCO3 can decrease its grain size from 311 to 53µm. Correspondingly, the tensile properties are obviously improved. The higher the cooling rate from addition temperature to pouring temperature or the higher the addition temperature, the finer the grains. The melt treated by MgCO3 should be...

  18. Electrical transport and thermochromic properties of polyaniline/chitosan/Co3O4 ternary nano composite

    Science.gov (United States)

    V, Mini; Kamath, Archana; S, Raghu; Chapi, Sharanappa; H, Devendrappa

    2015-06-01

    A new Polyaniline/ chitosan/ Co3O4 (CPAESCO) ternary nanocomposite is prepared by in situ oxidation polymerization of aniline in the presence of (NH4)2S2O8, chitosan and Co3O4. The Structural, Thermal, Optical and Electrical features of Polyaniline (PANI), Polyaniline/ chitosan (CPANI) and CPAESCO were analyzed using FT-IR, TGA, UV-vis analysis and Impedance spectroscopy by varying temperature. The results show that the introduction of the Co3O4 nanoparticles into CPANI matrix enhanced its properties. Mott's parameters show 3D -VRH Type conduction in it.

  19. Catalytic properties of Co3O4 nanoparticles for rechargeable Li/air batteries

    OpenAIRE

    Kim, Kwan Su; Park, Yong Joon

    2012-01-01

    Three types of Co3O4 nanoparticles are synthesized and characterized as a catalyst for the air electrode of a Li/air battery. The shape and size of the nanoparticles are observed using scanning electron microscopy and transmission electron microscopy analyses. The formation of the Co3O4 phase is confirmed by X-ray diffraction. The electrochemical property of the air electrodes containing Co3O4 nanoparticles is significantly associated with the shape and size of the nanoparticles. It appears t...

  20. First-principles calculations of structural, electronic, optical and elastic properties of magnesite MgCO 3 and calcite CaCO 3

    Science.gov (United States)

    Brik, M. G.

    2011-02-01

    Detailed ab initio calculations of the structural, electronic, optical and elastic properties of two crystals - magnesite (MgCO 3) and calcite (CaCO 3) - are reported in the present paper. Both compounds are important natural minerals, playing an important role in the carbon dioxide cycling. The optimized crystal structures, band gaps, density of states diagrams, elastic constants, optical absorption spectra and refractive indexes dependence on the wavelength all have been calculated and compared, when available, with literature data. Both crystals are indirect band compounds, with calculated band gaps of 5.08 eV for MgCO 3 and 5.023 eV for CaCO 3. Both values are underestimated by approximately 1.0 eV with respect to the experimental data. Although both crystals have the same structure, substitution of Mg by Ca ions leads to certain differences, which manifest themselves in noticeable change in the electronic bands profiles and widths, shape of the calculated absorption spectra, and values of the elastic constants. Response of both crystals to the applied hydrostatic pressure was analyzed in the pressure range of phase stability, variations of the lattice parameters and characteristic interionic distances were considered. The obtained dependencies of lattice constants and calculated band gap on pressure can be used for prediction of properties of these two hosts at elevated pressures that occur in the Earth's mantle.

  1. PP/纳米CaCO3分散体系的研究%Study of Dispersants for PP/nano-CaCO3 Blend

    Institute of Scientific and Technical Information of China (English)

    李远; 陈建国; 陈腊琼; 王正东

    2001-01-01

    本文研究了不同的分散剂对PP/纳米CaCO3体系的分散效果,以及加工工艺条件对该体系的影响。结果表明:超分散剂CH-1A对纳米CaCO3有显著的分散作用,使体系的冲击强度有了大幅度提高。在使PP完全塑化的前提下,超分散剂CH-1A使纳米CaCO3在PP中随转速的提高其分散效果也提高,使体系具有较好的加工性能。%Dispering effects of three different kinds of dispersants on PP/nano-CaCO3 system and influences of processing parameters on it were studied,the results showed that hyper-dispersant CH-1A had the most excellent dispering effect on nonao-calcium carbonate in PP and made the impact strength of the system markedly improved.The dispering effect of hyper-dispersant CH-1A became better with the increase of rolling speed if PP was wholly plasticized and made the system have a better processing properties.

  2. Mechano-activated preparation of CaCO3/RCOO- compound material and its characterization ( Ⅱ )-the action mechanism of RCOO- and CaCO3%CaCO3/RCOO-复合材料的制备与性能研究(Ⅱ)——RCOO-与CaCO3表面作用机理

    Institute of Scientific and Technical Information of China (English)

    丁浩

    2006-01-01

    采用红外光谱、X光电子能谱和吸附强度试验等手段,研究了机械力化学方法制备CaCO3/RCOO-复合材料过程中RCOO-与CaCO3表面的作用机理.结果表明,RCOO-以化学和物理作用两种方式在caCO3表面吸附,并以化学吸附为主,物理吸附为辅.还建立了RCOO-在CaCO3表面的化学吸附模型.

  3. 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 ℃.

  4. 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.

  5. Controllable synthesis of self-assembly Co3O4 nanoflake microspheres for electrochemical performance

    Science.gov (United States)

    Liu, Fangyan; Zhang, Binbin; Su, Hai; Zhang, Haitao; Zhang, Lei; Yang, Weiqing

    2016-09-01

    Tuning the ratios of ethanol to water, self-assembling microspheres composed of Co3O4 nanoflakes are synthesized by the hydrothermal method. The scanning electron microscopy (SEM) images of as-grown samples obviously show that the dispersive multilayered structures gradually change into micro/nanobelts and cubic blocks structures, and then into the desired self-assembled microspheres with increasing ratios of ethanol to water. Also, all the x-ray diffraction (XRD) patterns evidently demonstrate that all obtained Co3O4 has cubic crystal structure. The corresponding synthesis mechanism is discussed in detail. More importantly, the unique self-assembling Co3O4 nanoflake microspheres have excellent electrochemical performance with large specific capacitance, good rate capability and excellent cycling performance, evidently presenting a potential capability of Co3O4 nanoflake microspheres to act as electrode materials for supercapacitors in sustainable power sources.

  6. Preparation and electrochemical capacitance of cobalt oxide (Co3O4) nanotubes as supercapacitor material

    International Nuclear Information System (INIS)

    Cobalt oxide (Co3O4) nanotubes have been successfully synthesized by chemically depositing cobalt hydroxide in anodic aluminum oxide (AAO) templates and thermally annealing at 500 oC. The synthesized nanotubes have been characterized by scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). The electrochemical capacitance behavior of the Co3O4 nanotubes electrode was investigated by cyclic voltammetry, galvanostatic charge-discharge studies and electrochemical impedance spectroscopy in 6 mol L-1 KOH solution. The electrochemical data demonstrate that the Co3O4 nanotubes display good capacitive behavior with a specific capacitance of 574 F g-1 at a current density of 0.1 A g-1 and a good specific capacitance retention of ca. 95% after 1000 continuous charge-discharge cycles, indicating that the Co3O4 nanotubes can be promising electroactive materials for supercapacitor.

  7. 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 fc...... cobalt (Co). Removal of boron residues from the final product was established by surface characterization. Magnetic moment of these nanocomposite particles is relevant to magnetic field processing....

  8. Ultrasound-assisted green synthesis of nanocrystalline Co3O4 in the ionic liquid

    International Nuclear Information System (INIS)

    Cobalt oxide Co3O4 nanoparticles have been synthesized via sonochemical method in an ionic liquid, 1-Ethyl-3-methylimidazolium tetrafluoroborate [EMIM][BF4] for the first time. The crystal structure of Co3O4 nanoparticles has been characterized by using powder X-ray diffraction (XRD). Morphology has been characterized by transmission electron microscopy (TEM). The optical properties were studied by UV-VIS Spectrometer

  9. Co3O4 Nanocrystals on Graphene as a Synergistic Catalyst for Oxygen Reduction Reaction

    OpenAIRE

    Liang, Yongye; Li, Yanguang (Charles); Wang, Hailiang; Zhou, Jigang; Wang, Jian; Regier, Tom; Dai, Hongjie

    2011-01-01

    Catalysts for oxygen reduction and evolution reactions are at the heart of key renewable energy technologies including fuel cells and water splitting. Despite tremendous efforts, developing oxygen electrode catalysts with high activity at low costs remains a grand challenge. Here, we report a hybrid material of Co3O4 nanocrystals grown on reduced graphene oxide (GO) as a high-performance bi-functional catalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). While Co3O...

  10. PE/CaCO3-nanocomposites synthesized by in-situ polymerization

    Institute of Scientific and Technical Information of China (English)

    SCHARLACH Katrin; KAMINSKY Walter

    2007-01-01

    Polyethylene-nanocomposites with CaCO3-weight fractions from 0 to 15 wt.% were prepared by in-situ polymerization with Me2Si(Ind)2ZrCl2/MAO metallocene catalysts. A high activity especially in the presence of TIBA was observed. The morphology was investigated by using raster electron microscopy (REM) showing that the CaCO3-nanoparticles are uniformly distributed. The melting temperatures and the crystallization temperatures are not much influenced by increasing filler content.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Investigation of CO and formaldehyde oxidation over mesoporous Ag/Co3O4 catalysts

    Institute of Scientific and Technical Information of China (English)

    Fangli; Yu; Zhenping; Qu; Xiaodong; Zhang; Qiang; Fu; Yi; Wang

    2013-01-01

    CO and formaldehyde(HCHO)oxidation reactions were investigated over mesoporous Ag/Co3O4 catalysts prepared by one-pot(OP)and impregnation(IM)methods.It was found that the one-pot method was superior to the impregnation method for synthesizing Ag/Co3O4 catalysts with high activity for both reactions.It was also found that the catalytic behavior of mesoporous Co3O4 and Ag/Co3O4 catalysts for the both reactions was different.And the addition of silver on mesoporous Co3O4 did not always enhance the catalytic activity of final catalyst for CO oxidation at room temperature(20 C),but could significantly improve the catalytic activity of final catalyst for HCHO oxidation at low temperature(90 C).The high surface area,uniform pore structure and the pretty good dispersion degree of the silver particle should be responsible for the excellent low-temperature CO oxidation activity.However,for HCHO oxidation,the addition of silver played an important role in the activity enhancement.And the silver particle size and the reducibility of Co3O4 should be indispensable for the high activity of HCHO oxidation at low temperature.

  17. 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...

  18. 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.

  19. 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.

  20. 红掌ANR基因克隆及其表达与佛焰苞颜色的相关性分析%Cloning of ANR Gene from Anthurium and Relativity Analysis of Its Expression with the Spath Color

    Institute of Scientific and Technical Information of China (English)

    李雪; 李志英; 丛汉卿; 徐立

    2013-01-01

    Anthocyanidin is an important content for plant color appearence. Caltivars of A nthurium andraeanum display varies spathe colors have different concentrations of anthocyanidin. In anthocyanin biosynthetic pathway, Anthocyanidin Reductase (ANR) is a key enzyme to catalyze anthocyanidins to proanthocyanidin (PC). In order to verify the regulation of ANR in anthocyanin synthesis, we cloned the whole cDNA sequence of ANR by RACE technology according to the known ANR fragment from SSH library. BLAST results showed that A nA NR had high similarity, 72%~75%, with reported ANR gene from Populus trichocarpa, Camellia sinensis and V itis vinifera. RT-PCR results showed that in anthurium cultivars with different spathe colors, the expression level of A nA NR was negatively related with the accumulation of anthocyanidin.%花青素是植物颜色形成的重要成分之一。不同红掌品种中的花青素含量与佛焰苞颜色密切相关。花青素还原酶(ANR)是植物花青素调控代谢途径中催化产生原花青素的一个重要基因。为了探明ANR对花青素合成的作用,本研究根据从抑制差减文库中获得的基因片段,采用RACE技术克隆红掌ANR基因cDNA全长序列。BLAST结果显示,红掌ANR基因全长核苷酸序列与已报道的植物(葡萄,茶树,毛果杨等)同源性为72%~75%,氨基酸序列的同源性则达到78%~79%。RT-PCR结果表明ANR在不同颜色的红掌佛焰苞中表达有差异,其表达量与花青素含量成负相关。

  1. Activity-composition relations in the system CaCO 3-MgCO 3 predicted from static structure energy calculations and Monte Carlo simulations

    Science.gov (United States)

    Vinograd, Victor L.; Burton, Benjamin P.; Gale, Julian D.; Allan, Neil L.; Winkler, Björn

    2007-02-01

    Thermodynamic mixing properties and subsolidus phase relations of the rhombohedral carbonate system, (1 - x) · CaCO 3 - x · MgCO 3, were modelled in the temperature range of 623-2023 K with static structure energy calculations based on well-parameterised empirical interatomic potentials. Relaxed static structure energies of a large set of randomly varied structures in a 4 × 4 × 1 supercell of R3¯c calcite ( a = 19.952 Å, c = 17.061 Å) were calculated with the General Utility Lattice Program (GULP). These energies were cluster expanded in a basis set of 12 pair-wise effective interactions. Temperature-dependent enthalpies of mixing were calculated by the Monte Carlo method. Free energies of mixing were obtained by thermodynamic integration of the Monte Carlo results. The calculated phase diagram is in good agreement with experimental phase boundaries.

  2. Insight into the Li2CO3-K2CO3 eutectic mixture from classical molecular dynamics: Thermodynamics, structure, and dynamics

    Science.gov (United States)

    Corradini, Dario; Coudert, François-Xavier; Vuilleumier, Rodolphe

    2016-03-01

    We use molecular dynamics simulations to study the thermodynamics, structure, and dynamics of the Li2CO3-K2CO3 (62:38 mol. %) eutectic mixture. We present a new classical non-polarizable force field for this molten salt mixture, optimized using experimental and first principles molecular dynamics simulations data as reference. This simple force field allows efficient molecular simulations of phenomena at long time scales. We use this optimized force field to describe the behavior of the eutectic mixture in the 900-1100 K temperature range, at pressures between 0 and 5 GPa. After studying the equation of state in these thermodynamic conditions, we present molecular insight into the structure and dynamics of the melt. In particular, we present an analysis of the temperature and pressure dependence of the eutectic mixture's self-diffusion coefficients, viscosity, and ionic conductivity.

  3. Sensitivity of pelagic CaCO3 dissolution to ocean acidification in an ocean biogeochemical model

    Directory of Open Access Journals (Sweden)

    A. Regenberg

    2013-07-01

    Full Text Available In ocean biogeochemical models pelagic CaCO3 dissolution is usually calculated as R = k * Sn, where k is the dissolution rate constant transforming S, the degree of (under- saturation of seawater with respect to CaCO3, into a time dependent rate R, and n is the reaction rate order. Generally, there are two ways to define the saturation state of seawater with respect to CaCO3: (1 Δ[CO32−], which reflects the difference between the in-situ carbonate ion concentration and the saturation concentration, and (2 Ω, which is approximated by the ratio of in-situ carbonate ion concentration over the saturation concentration. Although describing the same phenomenon, the deviation from equilibrium, both expressions are not equally applicable for the calculation of CaCO3 dissolution in the ocean across pressure gradients, as they differ in their sensitivity to ocean acidification (change of [CO32−] over depth. In the present study we use a marine biogeochemical model to test the sensitivity of pelagic CaCO3 dissolution to ocean acidification (1–4 × CO2 + stabilization, exploring the possible parameter space for CaCO3 dissolution kinetics as given in the literature. We find that at the millennial time scale there is a wide range of CaCO3 particle flux attenuation into the ocean interior (e.g. a reduction of −55 to −85% at 1000 m depth, which means that there are significant differences in the impact on particle ballasting, depending on the kinetic expression applied.

  4. 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.

  5. Plasma-Engraved Co3 O4 Nanosheets with Oxygen Vacancies and High Surface Area for the Oxygen Evolution Reaction.

    Science.gov (United States)

    Xu, Lei; Jiang, Qianqian; Xiao, Zhaohui; Li, Xingyue; Huo, Jia; Wang, Shuangyin; Dai, Liming

    2016-04-18

    Co3 O4 , which is of mixed valences Co(2+) and Co(3+) , has been extensively investigated as an efficient electrocatalyst for the oxygen evolution reaction (OER). The proper control of Co(2+) /Co(3+) ratio in Co3 O4 could lead to modifications on its electronic and thus catalytic properties. Herein, we designed an efficient Co3 O4 -based OER electrocatalyst by a plasma-engraving strategy, which not only produced higher surface area, but also generated oxygen vacancies on Co3 O4 surface with more Co(2+) formed. The increased surface area ensures the Co3 O4 has more sites for OER, and generated oxygen vacancies on Co3 O4 surface improve the electronic conductivity and create more active defects for OER. Compared to pristine Co3 O4 , the engraved Co3 O4 exhibits a much higher current density and a lower onset potential. The specific activity of the plasma-engraved Co3 O4 nanosheets (0.055 mA cm(-2) BET at 1.6 V) is 10 times higher than that of pristine Co3 O4 , which is contributed by the surface oxygen vacancies. PMID:26990905

  6. Research and characterization of nano - CaCO3 dispersed in polystyrene%纳米CaCO3在PS中分散的表征和规律研究

    Institute of Scientific and Technical Information of China (English)

    王旭; 濮阳楠; 黄锐; 任志军; 陈海涛

    2001-01-01

    粒度分析结果表明,CaCO3在聚苯乙烯中的分散符合Rosin-Rammler分布.实验表明,随CaCO3中偶联剂用量、聚苯乙烯中CaCO3含量的增加以及体系在混炼过程中所受剪切程度的降低,体系中CaCO3的特征粒径逐渐增大.但上述三因素对CaCO3的分散指数影响不大.

  7. Research on the formula of PVC door & window profiles containing nano-CaCO3%添加纳米CaCO3的PVC门窗异型材的配方研究

    Institute of Scientific and Technical Information of China (English)

    杨秀岭; 苗乃芬; 韩正

    2008-01-01

    采用转矩流变仪对纳米CaCO3、普通CaCO3进行了对比研究,总结出了纳米CaCo3的性能特点,并结合实际生产经验,经过多次试验,确定了纳米CaCO3、普通CaCO3的最佳配比组合,研究出成本较低、质量较好的PVC门窗异型材生产配方.

  8. 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

  9. 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.

  10. Co3O4 based catalysts for NO oxidation and NOx reduction in fast SCR process

    International Nuclear Information System (INIS)

    Reaction activities of several developed catalysts for NO oxidation and NOx (NO + NO2) reduction have been determined in a fixed bed differential reactor. Among all the catalysts tested, Co3O4 based catalysts are the most active ones for both NO oxidation and NOx reduction reactions even at high space velocity (SV) and low temperature in the fast selective catalytic reduction (SCR) process. Over Co3O4 catalyst, the effects of calcination temperatures, SO2 concentration, optimum SV for 50% conversion of NO to NO2 were determined. Also, Co3O4 based catalysts (Co3O4-WO3) exhibit significantly higher conversion than all the developed DeNOx catalysts (supported/unsupported) having maximum conversion of NOx even at lower temperature and higher SV since the mixed oxide Co-W nanocomposite is formed. In case of the fast SCR, N2O formation over Co3O4-WO3 catalyst is far less than that over the other catalysts but the standard SCR produces high concentration of N2O over all the catalysts. The effect of SO2 concentration on NOx reduction is found to be almost negligible may be due to the presence of WO3 that resists SO2 oxidation. (author)

  11. Tuneable ultra high specific surface area Mg/Al-CO3 layered double hydroxides.

    Science.gov (United States)

    Chen, Chunping; Wangriya, Aunchana; Buffet, Jean-Charles; O'Hare, Dermot

    2015-10-01

    We report the synthesis of tuneable ultra high specific surface area Aqueous Miscible Organic solvent-Layered Double Hydroxides (AMO-LDHs). We have investigated the effects of different solvent dispersion volumes, dispersion times and the number of re-dispersion cycles specific surface area of AMO-LDHs. In particular, the effects of acetone dispersion on two different morphology AMO-LDHs (Mg3Al-CO3 AMO-LDH flowers and Mg3Al-CO3 AMO-LDH plates) was investigated. It was found that the amount of acetone used in the dispersion step process can significantly affect the specific surface area of Mg3Al-CO3 AMO-LDH flowers while the dispersion time in acetone is critical factor to obtain high specific surface area Mg3Al-CO3 AMO-LDH plates. Optimisation of the acetone washing steps enables Mg3Al-CO3 AMO-LDH to have high specific surface area up to 365 m(2) g(-1) for LDH flowers and 263 m(2) g(-1) for LDH plates. In addition, spray drying was found to be an effective and practical drying method to increase the specific surface area by a factor of 1.75. Our findings now form the basis of an effective general strategy to obtain ultrahigh specific surface area LDHs. PMID:26308729

  12. 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.

  13. 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.

  14. PUA/PSS multilayer coated CaCO3 microparticles as smart drug delivery vehicles.

    Science.gov (United States)

    Du, Chao; Shi, Jun; Shi, Jin; Zhang, Li; Cao, Shaokui

    2013-10-01

    Hybrid CaCO3 microparticles coated by sodium poly(styrene sulfonate) (PSS) and aliphatic poly(urethane-amine) (PUA) were developed as thermal-/pH-responsive drug delivery vehicles via LbL self-assembly technique. The DOX release from the CaCO3 microparticles was higher than 60% within 36 h, whereas the value of PUA/PSS-coated microparticles was only 20%. The results demonstrated that the PUA/PSS multilayer coating could reduce the drug release rate and significantly assuage the initial burst release of DOX. In addition, the drug release of the hybrid microparticles was found to be thermal-/pH-dual responsive. More interestingly, more than 90% of DOX was released in 36 h at pH2.1 and 55 °C owing to the combined action of the dissolution of the CaCO3 core and the shrinkage of aliphatic PUA. PMID:23910272

  15. Synthesis and Characterization of MWCNT/ CaCO3 Hybrid Compound

    International Nuclear Information System (INIS)

    Since their discovery, carbon nano tubes (CNT) have been actively researched and drawn a great interest for a wide variety of potential application. Several of synthesis method have been developed for the production of CNT. In this work, the chemical vapor deposition (CVD) technique was used to synthesis the multi walled carbon nano tubes/ calcium carbonate (MWCNT/ CaCO3) hybrid compound. A gas mixture of CH4/ N2 was used as the source of carbon and Ni/ CaCO3 compound was used as catalyst for the growth of the hybrid compound. The catalyst was prepared using nickel salt and CaCO3 mixture via coprecipitation method. The process was then followed by drying, calcination, reduction and growth the CNT in the tube furnace. The resulted compound was then analysed using XRD, SEM and HRTEM. (author)

  16. 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.

  17. DFT Study on the Co-Xe Bond in the HCo(CO3Xe Adduct

    Directory of Open Access Journals (Sweden)

    Tamás Kégl

    2014-01-01

    Full Text Available The metal-xenon interaction has been studied in hydrido-cobalt-carbonyl complexes by means of density functional methods. The method of choice has been selected after testing various functionals including dispersion correction on the bond dissociation enthalpy of Xe in the Cr(CO5Xe adduct. In general, the long range corrected versions of popular gradient-corrected functionals performed well. In particular, LC-mPWPW91 resulted in a perfect match with available experimental data; therefore this functional was selected for the computation of HCo(CO3Xe adducts. For HCo(CO3Xe two isomers have been located; the structure with CS symmetry has proved to be more stable by 5.3 kcal/mol than the C3V adduct in terms of free energy. The formation of HCo(CO3Xe is, however, endergonic by 3.5 kcal/mol for the CS isomer.

  18. Ultrathin mesoporous Co3O4 nanosheets on Ni foam for high-performance supercapacitors

    International Nuclear Information System (INIS)

    Ultrathin Co3O4 nanosheets with a mesoporous structure and a large surface area are hydrothermally grown on a three dimensional nickel foam. The ultrathin mesoporous Co3O4 nanosheets are grown on Ni foam with robust adhesion, which endows fast ion and electron transport, large electroactive surface area, and excellent structural stability. Such unique nanoarchitecture exhibits remarkable electrochemical performance with high capacitance and desirable cycle life. When evaluate as an electrode material for supercapacitors, the Co3O4 nanosheets electrode is able to deliver high specific capacitance of 2194 F g−1 at a current density of 1 A g−1 in 1 M KOH aqueous solution. The electrode also exhibits excellent cycling stability by retaining 93.1% of the maximum capacitance after 5000 charge-discharge cycles. The fabrication strategy presented here is facile, cost-effective, and can offer a way for energy storage device applications

  19. Co3O4@MWCNT nanocable as cathode with superior electrochemical performance for supercapacitors.

    Science.gov (United States)

    Wang, Xiaowei; Li, Minxia; Chang, Zheng; Yang, Yaqiong; Wu, Yuping; Liu, Xiang

    2015-02-01

    Using a simple hydrothermal procedure, cobalt oxide (Co3O4) with preferred orientation along (220) planes is in situ prepared and coated on MWCNT. The prepared Co3O4@MWCNT nanocable shows superior electrochemical performance as cathode material for aqueous supercapacitors in 0.5 M KOH solution. Its redox peaks retain the well-defined shapes even when the scan rate increases to 200 mV/s. Its specific capacitance is high, 590 F/g at 15 A/g and 510 F/g even at 100 A/g within the potential range from -0.2 to 0.58 V (vs SCE). There is no capacitance fading after 2000 full cycles. This excellent performance is superior to the pristine and the reported Co3O4, which is ascribed to the unique nanocable structure with orientation. PMID:25591171

  20. A high-pressure study of PbCO3 by XRD and Raman spectroscopy

    Science.gov (United States)

    Zhang, Yu-Feng; Liu, Jing; Qin, Zhen-Xing; Lin, Chuan-Long; Xiong, Lun; Li, Rui; Bai, Li-Gang

    2013-03-01

    The pressure-induced phase transitions of PbCO3 are studied using synchrotron radiation in a diamond anvil cell at room temperature. The XRD measurement indicates that PbCO3 with an initial phase of aragonite-type structure undergoes two phase transitions at ~7.8 GPa and ~15.7 GPa, respectively. The higher-pressure phase appearing at ~15.7 GPa is stable up to 51.8 GPa. The two phase transitions are further confirmed by Raman scattering up to 23.3 GPa. During the decompression process, the high-pressure phases of PbCO3 are gradually recovered to the starting aragonite-type structure, but exhibit some hysteresis. The bulk modulus B0 of the aragonite-type structure is obtained to be 63±(3) GPa by fitting the volume-pressure data to the Birch—Murnaghan equation of states with B'0 fixed to 4.

  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. Nanosheets Co3O4 Interleaved with Graphene for Highly Efficient Oxygen Reduction.

    Science.gov (United States)

    Odedairo, Taiwo; Yan, Xuecheng; Ma, Jun; Jiao, Yalong; Yao, Xiangdong; Du, Aijun; Zhu, Zhonghua

    2015-09-30

    Efficient yet inexpensive electrocatalysts for oxygen reduction reaction (ORR) are an essential component of renewable energy devices, such as fuel cells and metal-air batteries. We herein interleaved novel Co3O4 nanosheets with graphene to develop a first ever sheet-on-sheet heterostructured electrocatalyst for ORR, whose electrocatalytic activity outperformed the state-of-the-art commercial Pt/C with exceptional durability in alkaline solution. The composite demonstrates the highest activity of all the nonprecious metal electrocatalysts, such as those derived from Co3O4 nanoparticle/nitrogen-doped graphene hybrids and carbon nanotube/nanoparticle composites. Density functional theory (DFT) calculations indicated that the outstanding performance originated from the significant charge transfer from graphene to Co3O4 nanosheets promoting the electron transport through the whole structure. Theoretical calculations revealed that the enhanced stability can be ascribed to the strong interaction generated between both types of sheets. PMID:26345714

  3. 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.

  4. 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.

  5. A facile method to fabricate porous Co3O4 hierarchical microspheres

    International Nuclear Information System (INIS)

    Flower-like Co3O4 hierarchical microspheres composed of self-assembled porous nanoplates have been prepared by a two-step method without employing templates. The first step involves the synthesis of flower-like Co(OH)2 microspheres by a solution route at low temperatures. The second step includes the calcination of the as-prepared Co(OH)2 microspheres at 200 deg. C for 1 h, causing their decomposition to form porous Co3O4 microspheres without destruction of their original morphology. The samples were characterized by scanning electron microscope, transmission electron microscope, X-ray diffractormeter and Fourier transform infrared spectroscope. Some experimental factors including solution temperature and surfactant on the morphologies of the final products have been investigated. The magnetic properties of Co3O4 microspheres were also investigated. - Graphical Abstract: Flower-like Co3O4 microspheres are composed of self-assembled nanoplates and these nanoplates appear to be closely packed in the microspheres. These nanoplates consist of a large number of nanocrystallites less than 5 nm in size with a porous structure, in which the connection between nanocrystallites is random. Research Highlights: → Flower-like Co3O4 hierarchical microspheres composed of self-assembled porous nanoplates have been prepared by a two-step method without employing templates. → Layered Co(OH)2 microspheres were prepared with an appropriate approach under low temperatures for 1 h reaction. → Calcination caused Co(OH)2 decomposition to form porous Co3O4 microspheres without destruction of their original morphology.

  6. Insight into electrochemical properties of Co3O4–modified magnetic polymer electrolyte

    International Nuclear Information System (INIS)

    Highlights: • A novel cobaltosic oxide-modified magnetic agarose electrolyte. • Magnetic field–induced ordered microstructure and increased ionic conductivity. • Improved recombination process and good long-term stability of DSSCs after magnetic field treatment. • Better photovoltaic performance of the Co3O4-modified DSSC than that of NiO-modified DSSC under magnetic field treatment. - Abstract: Agarose–based electrolyte containing magnetic Co3O4 nanoparticles is studied for quasi–solid–state dye–sensitized solar cells (DSSCs) under external magnetic field treatment. SEM studies reveal the existence of oriented microstructure in Co3O4–modified agarose electrolyte film under proper magnetic field intensity. The formation mechanism of this ordered structure induced by magnetic field is analyzed. The impedance analysis shows that the ionic conductivity of Co3O4–modified agarose electrolyte is obviously increased by applying magnetic field intensity of 25 mT. Improved electron recombination process and photoelectric performance are observed in DSSCs under certain magnetic field treatment by electrochemical impedance spectra (EIS) and photovoltaic studies. The DSSC treated with magnetic field can maintain the efficiency unchanged for 434 hours without sealing. This is attributed to the high ionic conductivity and improved electron transfer process in DSSC resulting from the magnetic field treatment. Comparison of photovoltaic performances for Co3O4 and NiO modified DSSCs under 25 mT magnetic field treatment shows that Co3O4-modified DSSC exhibits higher energy conversion efficiency than that of NiO-modified one at the same condition

  7. 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.

  8. 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.

  9. Testing the cation-hydration effect on the crystallization of Ca–Mg–CO3 systems

    OpenAIRE

    Xu, Jie; Yan, Chao; Zhang, Fangfu; Konishi, Hiromi; Xu, Huifang; Teng, H. Henry

    2013-01-01

    Magnesium-bearing carbonate minerals play critical roles in the health and function of the Earth system because they constitute a significant fraction of lithosphere carbon reservoir and build skeletal structures for the majority of marine invertebrate organisms. Despite wide occurrence, high-Mg and sole-Mg phases such as dolomite ([Ca,Mg]CO3) and magnesite (MgCO3) prove virtually impossible to be crystallized under ambient conditions. It has long been believed that Mg2+ hydration is the caus...

  10. Improved reactivity of large coal particles by K2CO3 addition during steam gasification

    OpenAIRE

    Coetzee, Sansha; Neomagus, Hein W J P; Bunt, John R.; Everson, Raymond C.

    2013-01-01

    In this study, the excess solution impregnation method was used to impregnate large coal particles (5 and 10 mm) with K2CO3, and the effect of the additive on steam gasification reactivity was investigated. A washed bituminous, medium rank-C Highveld coal, with an ash content of 12.6 wt.% (air-dried basis), was used for experimentation. The excess solution method was used to impregnate coal particles with the selected additive, K2CO3, and results from XRF analysis indicated that t...

  11. 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

    (vinyl alcohol) was performed to produce polymeric nanofibers embedding solid nanoparticles. Calcination of the obtained electrospun nanofiber mats in air at 600°C for 1h, produced Co3O4 nanofibers with rough surfaces containing ZnO nanoparticles (i.e., ZnO-doped Co3O4 nanofibers). The rough surfaced nanofibers......, containing ZnO nanoparticles (ZnNPs), were then exploited as seeds to produce ZnO nanobranches using a specific hydrothermal technique. Scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were employed to characterize the as-spun nanofibers and the calcined product. X-ray powder...

  12. 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.

  13. Observation of atomic steps on CaCO3 crystal surface

    Institute of Scientific and Technical Information of China (English)

    SunJie-Lin; HuJun; 等

    1998-01-01

    By using scanning polarization force microscopy,the deliquescence process and the atomic steps on the cleavage surface of CaCO3 in air were studied in situ.Under an exposure to medium umidity(-57%),the sloiw step movement has been observed.

  14. 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.

  15. CaCO3 nanoparticle synthesis by carbonation of lime solution in microemulsion systems

    NARCIS (Netherlands)

    Sugih, A.K.; Shukla, D.; Heeres, H.J.; Mehra, A.

    2007-01-01

    Various aspects of nanoparticle precipitation in gas-reverse micellar systems have been studied. The experimental system chosen for investigation deals with the precipitation of CaCO3 nanoparticles. The effect of operating variables, such as water-to-surfactant molar ratio, different continuous phas

  16. 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.

  17. 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. PMID:27093344

  18. Preparation and evaluation of New [99Tcm (CO3]+-Labelled phenanthroline complexes

    International Nuclear Information System (INIS)

    The chief requirement to determine if pharmaceuticals may be AD-tracer is that complexes can pass through BBB to enter the brain and have rapid clean from the brain. To develop early diagnose radiopharmaceuticals for Alzheimer's disease, new phenanthroline complexes 2-(9-anthryl)-1H-imidazo [4, 5-f] [1, 10] phenanthroline (aip) and 2-(9-anthryl)-1ethyl-imidazo [4, 5-f] [1, 10] phenanthroline (aeip) based on the early research of Ru complexes banding to DNA used for fluescence method were synthesized and labelled by 99Tcm-tricarbonyl core. Radiochemical purities of complexes 99Tcm(CO)+3-aip and 99Tcm(CO)+3-aeip were found to be more than 95% as proved by radio-HPLC. Paper electrophoresis show that these complexes are neutral. Biodistribution of these complexes in mice shows the higher early uptakes in brain(2 min, 99Tcm(CO)+3-aip: (1.028 ± 0.096)%ID/g; 99Tcm(CO)+3-aeip: (1.191 ± 0.197)%ID/g). (authors)

  19. Foaming of CRT panel glass powder using Na2CO3

    DEFF Research Database (Denmark)

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

    2014-01-01

    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...... 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 optimum foaming temperature for minimising density and maximising closed porosity is found to be between 1023 and 1123 K. The pore structure depends on the amount of added Na2CO3, viz, the pores generally become more open with increasing Na2CO3 content. A minimum density of 0·28 g/cm3 is found when 14 wt...

  20. Theoretical Study on Co3+ in Aqueous Solution in Terms of ABEEM/MM Model

    Institute of Scientific and Technical Information of China (English)

    GUAN,Qing-Mei; YANG,Zhong-Zhi

    2007-01-01

    A detailed theoretical investigation on Co3+ hydration in aqueous solution has been carried out by means of molecular dynamics (MD) simulations based on the atom-bond electronegativity equalization method fused into molecular mechanics (ABEEM/MM). The effective Co3+ ion-water potential has been constructed by fitting to ab initio structures and binding energies for ionic clusters. And then the ion-water interaction potential was applied in combination with the ABEEM-7P water model to molecular dynamics simulations of single Co3+(aq.) solution, managing to reproduce many experimental structural and dynamical properties of the solution. Here, not only the common properties (radial distribution function, angular distribution function and solvation energy) obtained for Co3+ in ABEEM-7P water solution were in good agreement with those from the experimental methods and other molecular dynamics simulations but also very interesting properties of charge distributions, geometries of water molecules, hydrogen bond, diffusion coefficients, vibrational spectra are investigated by ABEEM/MM model.

  1. Hierarchically triangular prism structured Co3O4: Self-supported fabrication and photocatalytic property

    Science.gov (United States)

    The formation of ammonium cobalt (II) phosphate was utilized to synthesize unprecedented 3D structures of Co3O4, triangular prisms and trunk-like structures, via a self-supported and organics-free method. The length of a triangular side of the prepared 3D triangular prisms is ~1...

  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. 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.

  4. 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.

  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

    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

  6. 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.

  7. 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.

  8. Morphological Control of Co3O4 and Its Photocatalytic Properties

    Science.gov (United States)

    Cobaltosic oxide (Co3O4), a p-type semiconductor, belongs to the normal spinel crystal structure based on a cubic close packing array of oxide ions. The size, surface, geometry, and crystal phase of catalysts are important parameters for controlling their chemical, optical, and ...

  9. Co3O4@Reduced Graphene Oxide Nanoribbon for high performance Asymmetric Supercapacitor

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted -- Abstract: In the work, we have successfully fabricated an aqueous, high potential asymmetric supercapacitor (ASC) based on Co3O4/reduced graphene oxide nanoribbon (RGONR) hybrid electrodes. Here, Co3O4/RGONR film worked as the positive electrode while RGONR film served as negative electrode in the designed ASC. Uniformly immobilized Co3O4 nanoparticles (NPs) onto graphene nanoribbon have the advantage of high electronic conductivity via underlying RGONR with short ion diffusion path in uniform mesoporous structure. As a consequence, ASC Co3O4/RGONR//RGONR exhibited 1.6 V wide operating potential window for charge storage along with significantly improved capacitive performance than symmetric counterpart. It also demonstrates superior device performance with energy density, 64.2 Wh kg−1 (much higher than that of symmetric cell) with high power density, 8.3 kW Kg−1 due to optimized mass ratio of the electrodes. In addition, it reveals long term charge/discharge cycling stability with ~94% capacitance retention after 2000 cycles. This high-performance hybrid ASC pave their way for promising applications of pulse power systems

  10. 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}.

  11. Enzyme-assisted growth of nacreous CaCO3/polymer hybrid nanolaminates via the formation of mineral bridges

    Science.gov (United States)

    Yeom, Bongjun; Char, Kookheon

    2016-06-01

    Laminated nanostructures in nacre have been adopted as models in the fabrication of strong, tough synthetic nanocomposites. However, the utilization of CaCO3 biominerals in these composites is limited by the complexity of the synthesis method for nanosized biominerals. In this study, we use the enzymatic reaction of urease to generate a nanoscale CaCO3 thin film to prepare CaCO3/polymer hybrid nanolaminates. Additional layers of CaCO3 thin film are consecutively grown over the base CaCO3 layer with the intercalation of organic layers. The morphology and crystallinity of the added CaCO3 layers depend strongly on the thickness of the organic layer coated on the underlying CaCO3 layer. When the organic layer is less than 20 nm thick, the amorphous CaCO3 layer is spontaneously transformed into crystalline calcite layer during the growth process. We also observe crystalline continuity between adjacent CaCO3 layers through interconnecting mineral bridges. The formation of these mineral bridges is crucial to the epitaxial growth of CaCO3 layers, similar to the formation of natural nacre.

  12. Preparation of Ag2O/Ag2CO3/MWNTs composite photocatalysts for enhancement of ciprofloxacin degradation

    Science.gov (United States)

    Wang, Huiqin; Li, Jinze; Huo, Pengwei; Yan, Yongsheng; Guan, Qingfeng

    2016-03-01

    The Ag2O/Ag2CO3/multi-walled carbon nanotube (MWNTs) composite photocatalysts were prepared by calcination of the obtained precipitate. The structures and morphology of as-prepared composite photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy, X-ray photoelectron spectroscopy (XPS). The Ag2O/Ag2CO3/MWNTs composite photocatalysts exhibit higher degradation rate of ciprofloxacin (CIP) than the pure Ag2CO3, Ag2O/Ag2CO3 and Ag2CO3/MWNTs under visible light irradiation. The amount of loaded Ag2CO3 onto MWNTs and calcined time for Ag2CO3/MWNTs were systematically investigated, and the optimal amount of loaded Ag2CO3 and calcined time of Ag2CO3/MWNTs are 150 wt% and 10 min, respectively. The highest photocatalytic degradation rate of CIP could reach 76% under optimal conditions. The active species trapping experiments were also analyzed, the results show that the holes are main contributor for the degradation processes of CIP, furthermore the electrons, rad O2- and rad OH are also crucially influenced the photocatalytic degradation processes of CIP. The possible photocatalytic processes of CIP with Ag2O/Ag2CO3/MWNTs composite photocatalyst are also proposed.

  13. Single Crystalline Co3O4 Nanocrystals Exposed with Different Crystal Planes for Li-O2 Batteries

    Science.gov (United States)

    Su, Dawei; Dou, Shixue; Wang, Guoxiu

    2014-08-01

    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}.

  14. 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.

  15. Study on Tensile Properties of PVC Drainage Pipe Synergistic with ACR/CaCO3%ACR与CaCO3协同作用对PVC管材拉伸性能的研究

    Institute of Scientific and Technical Information of China (English)

    王帮进

    2012-01-01

    CaCO3, ACR, CaCO3 and ACR blends on the tensile properties of PVCdrainage pipe. When the CaCO3 in an amount up to 20 parts and the ACR amount of 5 parts, The results showed that: the tensile strength is about 40MPa,the elongation at break reaches 120%.%分别研究了CaCO3、ACR、CaCO3与ACR共混体对PVC排水管材的拉伸性能的影响。CaCO3的用量达到20%、用量5%时,当ACR管材的拉伸强度为40MPa,断裂仲长率为120%。

  16. 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.

  17. New synthetic route to Mg–Al–CO3 layered double hydroxide using magnesite

    International Nuclear Information System (INIS)

    Highlights: ► The use of magnesite to prepare Mg–Al–CO3 LDH is novel. ► The result sample is systematically studied. ► Furthermore, the cost of preparing Mg–Al–CO3 LDH may be reduced through this synthetic route. ► In the synthesis process, there is no CO2 released. That is significant to environmental protection. - Abstract: A novel synthesis of Mg–Al–CO3 layered double hydroxide (LDH) through chemical precipitation and hydrothermal methods has been investigated in this paper. The advantages of this method are using magnesite as magnesium source and no CO2 released in the process of preparation. Mg–Al–CO3 LDH (ZY) prepared under the optimized condition (the molar ratio of magnesite and Al(NO3)3·9H2O was 2.5:1; the aging time and temperature were 16 h and 100 °C, respectively) was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric and differential thermal analyser (TG–DTA) and scanning electron microscope (SEM). The crystal morphology of the prepared LDH displays platelet-like structure with a hexagonal shape, which is agreed with the LDH produced by industrial chemicals. Through elemental analysis and inductively coupled plasma-atomic emission spectrometry (ICP-AES), the chemical formula of ZY is determined as Mg0.70Al0.30(OH)2(CO3)0.15·0.6H2O

  18. 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.

  19. 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..

  20. 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.

  1. Promotional effects of samarium on Co3O4 spinel for CO and CH4 oxidation

    Institute of Scientific and Technical Information of China (English)

    徐香兰; 韩红; 刘建军; 刘文明; 李文龙; 王翔

    2014-01-01

    A series of Co3O4 spinel catalysts modified by Sm were prepared by co-precipitation method and tested for CH4 and CO oxidation. The addition of a small amount of Sm into Co3O4 led to an improvement in the catalytic activity for both reactions. Co0.98Sm0.02 and Co0.95Sm0.05, the two samples with Co/Sm molar ratio of 0.98/0.02 and 0.95/0.05 in sequence, showed the similar and the highest activity for CH4 oxidation, with CH4 complete conversion at 450 ºC. In contrast, Co0.90Sm0.10 was the most active sample for CO oxidation, with CO complete conversion at 120 ºC. The catalysts were characterized by techniques of N2 adsor-tion-desorption with Brunauer-Emmett-Teller technique (N2-BET), X-ray powder diffraction (XRD), thermal gravity analy-sis-differential scanning calorimetry (TGA-DSC), H2 temperature programmed reduction (H2-TPR) and X-ray photoelectron spec-troscopy analysis (XPS). Compared with pure Co3O4, for Co1-xSmx catalysts with 0.02≤x≤0.10, the addition of a small amount of Sm resulted in the formation of spinel Co3O4 and amorphous SmCoO3, hence increasing the number of Co3+and the active surface oxygen species, which was responsible for the improvement of the activity. Co0.95Sm0.05 catalyst showed not only high thermal stability and activity but also good reaction durability in the presence of 5%water vapor for CH4 oxidation.

  2. 超细CaCO3对ABS材料力学性能的影响%Effect of ultrafine CaCO3 on mechanical properties of ABS blending material

    Institute of Scientific and Technical Information of China (English)

    钱岑; 李怀栋

    2013-01-01

    采用双螺杆挤出机熔融挤出共混的方法,在较高螺杆转速条件下研究了CaCO3表面处理剂品种、CaCO3颗粒直径及其含量等因素对ABS/弹性体/CaCO3共混材料力学性能和加工流动性能的影响.结果表明,在CaCO3颗粒直径1.08~1.96 μm、C型表面处理剂、螺杆转速480r/min、220℃的共混条件下,可制得综合力学性能较好的ABS/高胶粉(GP)/CaCO3(质量比62.9∶17.1∶20)和ABS/EVA/CaCO3(质量比74.6∶20.4∶5)共混材料.%The effect of CaCO3 surface treated agents,CaCO3 particle diameter and content on mechanical properties and the melt flow rate of ABS/elastomer/CaCO3 blending material is investigated by means of melt extrusion and blending with twin-screw extruder.The results show that the blending materials with better mechanical properties such as ABS/GP/CaCO3 (mass ratio:62.9/17.1/20)and ABS/EVA/CaCO3 (mass ratio:74.6/20.4/5) can be obtained under the conditions of CaCO3 particle diameter 1.08-1.96 μm,screw rotation speed 480 r/min and extrusion temperature 220 ℃.

  3. Study on Surface Modification of Nano-CaCO3 and Its Application in PP%Nano-CaCO3的表面改性及其在PP中的应用

    Institute of Scientific and Technical Information of China (English)

    崔文广; 高岩磊; 牟微; 雷霓

    2013-01-01

    选用钛酸酯偶联剂对纳米碳酸钙(nano-CaCO3)进行表面改性,以改善其在聚丙烯(PP)中的分散性.利用透射电镜(TEM)和扫描电镜(SEM)表征了nano-CaCO3的改性效果,研究了改性条件对PP/nano-CaCO3复合材料性能的影响.结果表明:在偶联剂用量2.0%、改性时间25 min、改性温度85℃的条件下,PP/nano-CaCO3复合材料的综合性能较好;改性后nano-CaCO3的分散性得到有效改善.%Nano-CaCO3 was modified by titanate coupling agent in order to improve its dispersion in PP. The modified effect of nano-CaCO3 was analyzed by TEM and SEM, and the effects of conditions of modification on property of PP/nano-CaCO3 composite were studied. The results show that the comprehensive properties of PP/nano-CaCO3 composite are optimal when nano-CaCO3 is modified by 2.0% coupling agent for 25 min at 85℃. The dispersion of modified nano-CaCO3 is better than that of unmodified nano-CaCO3.

  4. 填料表面处理对ABS/CaCO3复合材料性能的影响%Influence of filler's surface treatment on mechanical and thermal properties of ABS/CaCO3 composites

    Institute of Scientific and Technical Information of China (English)

    梁基照

    2004-01-01

    在室温下,测定了CaCO3填充丙烯腈-丁二烯-苯乙烯三元共聚物(ABS)复合材料的力学性能.结果表明,随着CaCO3质量分数[w(CaCO3)]的增加,试样的拉伸弹性模量呈非线性提高,而拉伸强度和拉伸断裂能下降.当w(CaCO3)小于10%时,试样的简支梁缺口冲击强度随着w(CaCO3)的增加而迅速减小,而弯曲强度却增大,w(CaCO3)达10%后两者均缓慢地减小.CaCO3的表面处理及其粒径大小对上述力学性能的影响不太明显.此外,测量了试样的维卡软化温度(Tvc),Tvc随着w(CaCO3)的增加而提高,这表明填充CaCO3粒子有利于改善ABS的耐热性能.

  5. Study on Friction Reducing and Anti-wear of CaCO3 Nanoparticles as Additives in Lubricating Oils

    Institute of Scientific and Technical Information of China (English)

    GUZhou-ming; GUCai-xiang; WANGRen-bin

    2004-01-01

    This paper has insepected the size mad the structure of the calcium carbonate (CaCO3) particles by adopting X-ray diffraction and transmission electron microscope (TEM). The suitable surfactants have been selected and put into lubricating oil with nanometer CaCO3 particles. By testing some parameters, such as the maximum non-seizure load, the shape and diameter of wear scar, the friction factor, the nanometer CaCO3 particles' properties of extreme pressure, anti-wear and friction reduction have been tested and analyzed. The properties of the nanometer CnCO3 particles' tribology chemistry have been analyzed through X-ray photoelectron spectrum (XPS) test. Also the nanometer CaCO3 particles' mechanism of anti-wear and friction reduction has been studied systematically. The research results show thai, the lubricating oil with nanometer CaCO3 particles have good tribological properties.

  6. Study on Friction Reducing and Anti-wear of CaCO3 Nanoparticles as Additives in Lubricating Oils

    Institute of Scientific and Technical Information of China (English)

    GU Zhou-ming; GU Cai-xiang; WANG Ren-bin

    2004-01-01

    This paper has insepected the size and the structure of the calcium carbonate (CaCO3) particles by adopting X-ray diffraction and transmission electron microscope (TEM). The suitable surfactants have been selected and put into lubricating oil with nanometer CaCO3 particles. By testing some parameters, such as the maximum non-seizure load, the shape and diameter of wear scar, the friction factor, the nanometer CaCO3 particles' properties of extreme pressure,anti-wear and friction reduction have been tested and analyzed. The properties of the nanometer CaCO3 particles' tribology chemistry have been analyzed through X-ray photoelectron spectrum (XPS) test. Also the nanometer CaCO3 particles'mechanism of anti-wear and friction reduction has been studied systematically. The research results show that, the lubricating oil with nanometer CaCO3 particles have good tribological properties.

  7. 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.

  8. Effect of magnesium addition on structural and magnetic properties of NiO, Co3O4 nanoparticles

    International Nuclear Information System (INIS)

    Magnesium added NiO and Co3O4 nanoparticles were prepared from microwave assisted method. The cubic phase natures of NiO, Co3O4 nanoparticles have been ascertained from X-ray diffraction. XRD pattern reveals the size of the particles was reduced to quantum level for NiO than Co3O4 due to the addition of magnesium ion. FTIR spectra have been performed to identify the vibration peaks of metal oxygen. Room temperature magnetic measurement ensures small ferromagnetic nature for Mg added NiO with higher saturation magnetization. superparamagnetic nature was examined for Mg added Co3O4 nanoparticles

  9. 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.

  10. Neutron powder diffraction and magnetic studies of mesoporous Co3O4

    International Nuclear Information System (INIS)

    Samples of mesoporous Co3O4, created by using mesoporous silicas KIT-6 and SBA-16 as hard templates to control the growth of Co3O4 have been investigated with SQUID magnetometry and neutron powder diffraction, to reveal the effects of high surface area on the magnetic and electronic properties. DC magnetic susceptibility measurements show lower Neel ordering temperatures and lower magnetic moments than in a 'bulk' reference. A lower second transition temperature is also observed in the mesoporous samples, associated with the freezing of the surface (shell) magnetic moments. Measurements taken with increasing applied field at constant temperature show the materials to be antiferromagnetic as expected. Complementary parametric neutron powder diffraction studies show similar trends between the two mesoporous samples when looking at their Neel temperatures, and verify long range order within the samples.

  11. 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.

  12. 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.

  13. 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

    In solid oxide fuels cell stacks, the Fe-Cr interconnector plates and their oxidation scale formed during operation must have sufficiently high electrical conductivity at the operating temperature. It is anticipated that this can be achieved by reaction-diffusion between Co3O4 and the chromia scale...... 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...

  14. 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. PMID:26932759

  15. 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.

  16. 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

  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. 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.

  19. 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

  20. 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

  1. Nano-CaCO3/HDPE复合材料流变性能的研究%Study on Rheological Behavior of Nano-CaCO3/HDPE Composites

    Institute of Scientific and Technical Information of China (English)

    常杰云; 张帆

    2012-01-01

    通过熔融共混法制备了纳米碳酸钙/高密度聚乙烯( nano-CaCO3/HDPE)复合材料,使用旋转流变仪研究了复合材料的动态流变性能.结果表明,当nano-CaCO3加入量≤4%(质量分数)时,随着nano-CaCO3含量的增加,nano-CaCO3/HDPE复合材料的储能模量、损耗模量和复数黏度均高于纯HDPE,并逐渐上升.%By the method of melt blending, HDPE/nano-CaCO3composites were prepared and the dy-namic rheological properties were studied by rotational rheometer. The results indicated after nano-CaCO 3 was treated with silane coupling agent, with the increasing content ( ≤4% ) of namo-CaCO3, the storage modu-lus , loss modulus and complex viscosity were rising with the nano-CaCO3 content, and higher than that of pure HDPE.

  2. 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.

  3. 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.

  4. 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. PMID:22386308

  5. Preparation of Shape-Controlled Graphene/Co3O4 Composites for Supercapacitors

    Science.gov (United States)

    Chen, Jun; Chen, Ningna; Feng, Xiaomiao; Hou, Wenhua

    2016-09-01

    Graphene/Co3O4 nanocomposites with different morphologies were fabricated by hydrothermal method. The morphology of nanocomposites was characterized by scanning electron microscopy. These composites could be used as the electrode materials for supercapacitors. The eletrochemical behavior of the composite was tested by cyclic voltammetry and galvanostatic charge-discharge measurements in 1.0 mol/L KOH solution. The results showed that the graphene/Co3O4 nanopetal composite exhibited excellent electrochemical performance. The specific capacitance value could reach up to 714 F/g at a scan rate of 2 mV/s. Besides, the capacitance of the graphene/Co3O4 nanopetal composite was 841 F/g at a current density of 0.1 A/g. After galvanostatic charge-discharge 1000 laps at the current density of 0.4 A/g, the specific capacitance could keep 96.7% of original capacitive value, demonstrating its good cycling stability.

  6. 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.

  7. 12CO(3-2) Emission in Spiral Galaxies: Warm Molecular Gas in Action?

    CERN Document Server

    Galaz, Gaspar; Bronfman, Leonardo; Rubio, Monica

    2008-01-01

    Using the APEX sub-millimeter telescope we have investigated the 12CO(3-2) emission in five face-on nearby barred spiral galaxies, where three of them are high surface brightness galaxies (HSBs) lying at the Freeman limit, and two are low surface brightness galaxies (LSBs). We have positive detections for two of three HSB spirals and non-detections for the LSBs. For the galaxies with positive detection (NGC0521 and PGC070519), the emission is confined to their bulges, with velocity dispersions of ~90 and ~73 km/s and integrated intensities of 1.20 and 0.76 K/km/s, respectively. For the non-detections, the estimated upper limit for the integrated intensity is ~0.54 K/km/s. With these figures we estimate the H2 masses as well as the atomic-to-molecular mass ratios. Although all the galaxies are barred, we observe 12CO(3-2) emission only for galaxies with prominent bars. We speculate that bars could dynamically favor the 12CO(3-2) emission, as a second parameter after surface brightness. Therefore, secular evolu...

  8. Phase transitions ordering–phase separation in the Co3V alloy

    International Nuclear Information System (INIS)

    Highlights: • Ordering–phase separation transition in the Co3V alloy occurs two times. • A tendency to phase separation takes place above 800 and below 450 °C. • Ordering with L12 phase formation occurs in the 450–800 °C interval. - Abstract: An electron microscopic study of the Co3V alloy microstructure formed after heat treatment at different temperatures has been conducted. Two phase transitions ordering–phase separation have been discovered, which occur in the alloy at temperatures of about 450 and 800 °C. At high-temperature phase separation, the microstructure consists of bcc vanadium atom particles and a fcc solid solution; at low-temperature phase separation, it is a cellular structure, in which the cellular boundaries are enriched in vanadium. In the region of ordering, it consists of particles of the Co3V chemical compound, randomly distributed in the solid solution. It is shown that at none of the temperatures do these microstructures correspond to those shown in the Co–V phase diagram.

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

    Science.gov (United States)

    T P, Ragesh Kumar; 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.

  10. Effect of Li 2CO 3 additive on gas generation in lithium-ion batteries

    Science.gov (United States)

    Shin, Jee-Sun; Han, Chi-Hwan; Jung, Un-Ho; Lee, Shung-Ik; Kim, Hyeong-Jin; Kim, Keon

    To elucidate the mechanism of gas generation during charge-discharge cycling of a lithium-ion cell, the generated gases and passive films on the carbon electrode are examined by means of gas chromatography (GC) and Fourier transform infrared (FTIR) spectroscopy. In ethyl carbonate/dimethyl carbonate and ethyl carbonate/diethyl carbonate 1 M LiPF 6 electrolytes, the detected gaseous products are CO 2, CO, CH 4, C 2H 4, C 2H 6, etc. The FTIR spectrum of the surface of the carbon electrode shows bands which correspond to Li 2CO 3, ROCO 2Li, (ROCO 2Li) 2, and RCO 2Li. These results suggest that gas evolution is caused by electrode decomposition, reactive trace impurities, and electrolyte reduction. The surface of the electrode is composed of electrolyte reduction products. When 0.05 M Li 2CO 3 is added as an electrolyte additive, the total volume of generated gases is reduced, and the discharge capacity and the conductivity of lithium-ions are increased. These results can be explained by a more compact and thin 'solid electrolyte interface' film on the carbon electrode formed by Li 2CO 3, which effectively prevents solvent co-intercalation and carbon exfoliation.

  11. 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.

  12. Porous Co3O4 hollow nanododecahedra for nonenzymatic glucose biosensor and biofuel cell.

    Science.gov (United States)

    Zhang, Erhuan; Xie, Yu; Ci, Suqin; Jia, Jingchun; Wen, Zhenhai

    2016-07-15

    Cobalt oxide hollow nanododecahedra (Co3O4-HND) is synthesized by a facile thermal transformation of cobalt-based metal-organic framework (Co-MOF, ZIF-67) template. The morphology and properties of the Co3O4-HND are characterized by a set of techniques, including transmission electron microscope (TEM), powder X-ray diffraction (XRD), scanning electron microscope (SEM) and Brunner-Emmet-Teller (BET). When tested as a non-enzymatic electrocatalyst for glucose oxidation reaction, the Co3O4-HND exhibits a high activity and shows an outstanding performance for determining glucose with a wide window of 2.0μM to 6.06mM, a high sensitivity of 708.4μAmM(-1)cm(-2), a low detection limit of 0.58μM (S/N=3), and fast response time(GFC) due to its excellent electrochemical properties, low cost and facile preparation. PMID:26918617

  13. 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.

  14. 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.

  15. Minicrystal and XPS Analysis of SiO2 coated superfine CaCO3 Powder%SiO2包覆超细CaCO3的微晶分析和XPS研究

    Institute of Scientific and Technical Information of China (English)

    华益苗; 袁骏; 岳林海; 蔡菊香

    2001-01-01

    The superfine CaCO3 powder coated with SiO2 was synthesized. Through XRD technique, the cell parameters and crystallite size of reference and coated CaCO3 were calculated. SiO2 present in the state of amorphous and prevent the agglomeration and growth of CaCO3 micro-crystal. By comparing the result of XPS analysis of reference compound to coated sample, CaCO3 has been coated successfully with SiO2. The thickness of the coating is about 2.4~3.4nm. From the difference (0. BeV increase) of the binding energy of Ca2p, we presume that the bind Si-O-Ca has formed in the surface of CaCO3.

  16. Effects of Surface-treated CaCO3 on Polyurethane Sealant Characteristics%表面处理CaCO3对单组分聚氨酯密封剂性能的影响

    Institute of Scientific and Technical Information of China (English)

    尚东升

    2005-01-01

    对轻质CaCO3、重质CaCO3和滑石粉3种填料进行了表面处理,考察了它们对聚氨酯密封剂性能的影响.结果表明:使用表面处理轻质CaCO3作填料的聚氨酯密封剂与使用未处理轻质CaCO3作填料制备的聚氨酯密封剂相比,其邵氏硬度降低,伸长率提高.此外,使用表面处理轻质CaCO3作填料时在增加填料用量的同时,能确保密封剂的物理机械性能.

  17. 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.

  18. 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.

  19. Facile synthesis of Co3O4 nanowires grown on hollow NiO microspheres with superior electrochemical performance

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted - Highlights: • The NiO hollow spheres were decorated by Co3O4 nanowires. • The NiO hollow spheres were comprised of many NiO particles. • The Co3O4 nanowires were composed of nanoparticles. • The NiO/Co3O4 core/shell nanocomposites have good electrochemical properties. - Abstract: The NiO/Co3O4 core/shell composites as a promising supercapacitor material have been fabricated by facile hydrothermal process. The structure and morphology of the NiO/Co3O4 core/shell composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicated that the NiO hollow spheres were decorated by Co3O4 nanowires, and the nanowires were composed of nanoparticles. Electrochemical properties were characterized by cyclic voltammetry, galvanostatic charge/discharge measurements, and electrochemical impedance spectroscopy. The results suggested that the NiO/Co3O4 core/shell composites had good electrochemical reversibility and displayed superior capacitive performance with large capacitance (510 F g−1). Moreover, NiO/Co3O4 core/shell composites showed excellent cyclic performanceafter 1000 cycles

  20. 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

  1. DFT+U study of polaronic conduction in Li2O2 and Li2CO3

    DEFF Research Database (Denmark)

    García Lastra, Juan Maria; Myrdal, J.S.G.; Christensen, Rune;

    2013-01-01

    that the performance of the battery decreases drastically when the amount of Li2CO3 at the cathode increases with respect to Li2O2. In this work, we study the formation and transport of hole and electron polarons in Li2O2 and Li2CO3 using density functional theory (DFT) within the PBE+U approximation. For both...

  2. Thiol- and thioether-based bifunctional chelates for the {M(CO)3}+ core (M = Tc, Re).

    Science.gov (United States)

    Lazarova, Neva; Babich, John; Valliant, John; Schaffer, Paul; James, Shelly; Zubieta, Jon

    2005-09-19

    By analogy to the recently described single amino acid chelate (SAAC) technology for complexation of the {M(CO)3}+ core (M = Tc, Re), a series of tridentate ligands containing thiolate and thioether groups, as well as amino and pyridyl nitrogen donors, have been prepared: (NC5H4CH2)2NCH2CH2SEt (L1); (NC5H4CH2)2NCH2CH2SH (L2); NC5H4CH2N(CH2CH2SH)2 (L3); (NC5H4CH2)N(CH2CH2SH)(CH2CO2R) [R = H (L4); R = -C2H5 (L5). The {Re(CO)3}+ core complexes of L1-L5 were prepared by the reaction of [Re(CO)3(H2O)3]Br or [NEt4]2[Re(CO)3Br3] with the appropriate ligand in methanol and characterized by infrared spectroscopy, 1H and 13C NMR spectroscopy, mass spectrometry, and in the case of [Re(CO)3(L2)] (Re-2) and [Re(CO)3(L1)Re(CO)3Br2] (Re-1a) by X-ray crystallography. The structure of Re-2 consists of discrete neutral monomers with a fac-Re(CO)3 coordination unit and the remaining coordination sites occupied by the amine, pyridyl, and thiolate donors of L2, leaving a pendant pyridyl arm. In contrast, the structure of Re-1a consists of discrete binuclear units, constructed from a {Re(CO)3(L1)}+ subunit linked to a {Re(CO)3Br2}- group through the sulfur donor of the pendant thioether arm. The series of complexes establishes that thiolate donors are effective ligands for the {M(CO)3}+ core and that a qualitative ordering of the coordination preferences of the core may be proposed: pyridyl nitrogen approximately thiolate > carboxylate > thioether sulfur > thiophene sulfur. The ligands L1 and L2 react cleanly with [99mTc(CO)3(H2O)3]+ in H2O/DMSO to give [99mTc(CO)3(L1)]+ (99m)Tc-1) and [99mTc(CO)3(L2)] (99mTc-2), respectively, in ca. 90% yield after HPLC purification. The Tc analogues 99mTc-1 and 99mTc-2 were subjected to ligand challenges by incubating each in the presence of 1000-fold excesses of both cysteine and histidine. The radiochromatograms showed greater than 95% recovery of the complexes. PMID:16156635

  3. 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......, the as-prepared Co3O4 hierarchical electrodes delivered high lithium storage properties comparing to the other Co3O4 nanostructures, including a high reversible capacity of 1053.1 mAhg-1 after 50 cycles at a current density of 0.2 C (1 C = 890 mAg-1), good cycling stability and rate capability....

  4. In Operando Identification of Geometrical-Site-Dependent Water Oxidation Activity of Spinel Co3O4.

    Science.gov (United States)

    Wang, Hsin-Yi; Hung, Sung-Fu; Chen, Han-Yi; Chan, Ting-Shan; Chen, Hao Ming; Liu, Bin

    2016-01-13

    Spinel Co3O4, comprising two types of cobalt ions: one Co(2+) in the tetrahedral site (Co(2+)(Td)) and the other two Co(3+) in the octahedral site (Co(3+)(Oh)), has been widely explored as a promising oxygen evolution reaction (OER) catalyst for water electrolysis. However, the roles of two geometrical cobalt ions toward the OER have remained elusive. Here, we investigated the geometrical-site-dependent OER activity of Co3O4 catalyst by substituting Co(2+)(Td) and Co(3+)(Oh) with inactive Zn(2+) and Al(3+), respectively. Following a thorough in operando analysis by electrochemical impedance spectroscopy and X-ray absorption spectroscopy, it was revealed that Co(2+)Td site is responsible for the formation of cobalt oxyhydroxide (CoOOH), which acted as the active site for water oxidation. PMID:26710084

  5. Porous nanocubic Mn3O4-Co3O4 composites and their application as electrochemical supercapacitors.

    Science.gov (United States)

    Pang, Huan; Deng, Jiawei; Du, Jimin; Li, Sujuan; Li, Juan; Ma, Yahui; Zhang, Jiangshan; Chen, Jing

    2012-09-14

    A simple approach has been developed to fabricate ideal supercapacitors based on porous Mn(3)O(4)-Co(3)O(4) nanocubic composite electrodes. We can easily obtain porous corner-truncated nanocubic Mn(3)O(4)-Co(3)O(4) composite nanomaterials without any subsequent complicated workup procedure for the removal of a hard template, seed or by using a soft template. In such a composite, the porous Mn(3)O(4)-Co(3)O(4) enables a fast and reversible redox reaction to improve the specific capacitance. The porous nanocubic Mn(3)O(4)-Co(3)O(4) composite electrode can effectively transport electrolytes and shorten the ion diffusion path, which offers excellent electrochemical performance. These results suggest that such porous Mn(3)O(4)-Co(3)O(4) composite nanocubes are very promising for next generation high-performance supercapacitors. PMID:22814313

  6. 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.

  7. 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.

  8. 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

    Science.gov (United States)

    Plazy, Mélanie; Farouki, Kamal El; Iwuji, Collins; Okesola, Nonhlanhla; Orne-Gliemann, Joanna; Larmarange, Joseph; Lert, France; Newell, Marie-Louise; Dabis, François; Dray-Spira, Rosemary

    2016-01-01

    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 test

  9. 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

  10. Sexual risk behaviour among people living with HIV according to the biomedical risk of transmission: results from the ANRS-VESPA2 survey

    Directory of Open Access Journals (Sweden)

    Marie Suzan-Monti

    2016-01-01

    Full Text Available Introduction: People living with HIV (PLHIV on antiretroviral therapy (ART, with sustained undetectable viral load (sUVL and no history of sexually transmitted infections for at least six months, are considered to have a low risk of HIV transmission (LRT. We aimed to characterize, in a representative sample of French PLHIV, the sexual behaviour of LRT PLHIV compared with non-LRT PLHIV. Methods: The cross-sectional ANRS-VESPA2 survey was conducted on adult PLHIV attending French hospitals in 2011. The LRT PLHIV group included participants with sUVL and no sexually transmitted infection for at least 12 months. Socio-behavioural and medical data were collected. Chi-square tests helped compare sexual risk indicators between LRT and non-LRT PLHIV. The survey's retrospective nature allowed us to perform complementary category-based analyses of LRT PLHIV according to whether they had sUVL for at least 18, 24 or 36 months in three socio-epidemiological groups: men who have sex with men (MSM, other men and women. Results: Analysis included 2638 PLHIV diagnosed >12 months with available viral load data. The proportion of LRT PLHIV varied from 58% (≥12 months sUVL to 38% (≥36 months sUVL. Irrespective of sUVL duration, we found the following: 1 LRT men (MSM and other men were more likely to report having no sexual partner than their non-LRT counterparts. Among men having sexual partners in the previous 12 months, no significant difference was seen between LRT and non-LRT men in the number of sexual partners. LRT women were less likely to report having more than one sexual partner than non-LRT women; 2 LRT MSM were more likely to report being in sexually inactive couples than their non-LRT counterparts; 3 among sexually active participants, no difference was observed between LRT and non-LRT PLHIV concerning condom use with their serodiscordant steady partner or with their most recent casual sexual partners. Conclusions: LRT PLHIV with sUVL ≥12 months

  11. 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

  12. Acceptance rate of clinical study endpoints and adequacy of source documentation: experience from clinical study endpoint review in NEAT001/ANRS143

    Directory of Open Access Journals (Sweden)

    Juan Berenguer

    2014-11-01

    Full Text Available Introduction: NEAT001/ANRS143 was an open-label, randomized, non-inferiority study comparing raltegravir+darunavir/r(RGV+DRV/r vs. tenofovir/emtricitabine+darunavir/r (TDF/FTC+DRV/r in HIV-infected antiretroviral naïve adults. Primary efficacy outcome was a composite of virological and clinical events by week 96. Materials and Methods: Clinical trial units collected and translated supporting documentation (SD related to the investigator-reported events. A coordinator checked events and SD for consistency and completeness. The Endpoint Review Committee (ERC determined if clinical events met pre-defined diagnostic criteria in categories “confirmed” or “probable”. The ERC of 12 experienced, independent clinicians served in groups of three conducting individual reviews in writing, blinded to treatment arm. Differences of opinion were adjudicated in a second review by direct dialogue between reviewers. “Confirmed” events required adequate SD like laboratory, radiographic or pathology diagnostic reports. “Probable” events were typically based on clinical criteria. Results: Of the 164 serious and 3,964 adverse events reported in the study, 133 qualified for endpoint review, for a total of 153 adjudications:Sixty of 111 per protocol endpoints were confirmed (n=53 or probable (n=7, which equals an acceptance rate of 54%. In two confirmed cases, SD was partly adequate and evaluation uncertain. Of 51 rejected events, 13 had insufficient SD, two were recurrent events. The rate of rejected events was comparable between treatments with 41% rejected events in the RGV+DRV/r arm compared to 52% in the TDF/FTC+DRV/r arm. The IRIS acceptance rate was low (3 of 18, demonstrating the difference in perception of IRIS in daily patient management and the stricter protocol definition. Conclusions: Blinded endpoint review prevented unacceptably high false positive event rates documenting that real-time ascertainment of clinical endpoints is crucial for

  13. Study on Mechanical Properties of PVC Synergistic Toughened with CPE/CaCO3%CPE与CaCO3协同增韧PVC力学性能的研究

    Institute of Scientific and Technical Information of China (English)

    张宁

    2012-01-01

    用CPE与CaCO3复配制备出高韧性PVC复合材料,研究了CPE、CaCO3对PVC复合材料力学性能的影响.结果表明:CPE能有效提高PVC的冲击强度;CaCO3在一定用量范围内,可以提高PVC的冲击强度;CPE与CaCO3协同增韧,PVC复合材料的冲击强度可达60 k J/m2,拉伸强度约为37 MPa,断裂伸长率可达65%.%The high toughness PVC composite was prepared by adding CPE and CaCO3 Into PVC, and the effects of CaCO3 and CPE on mechanical properties of PVC were studied. The results show that: the impact strength of PVC improves with the using amount of CaCO3 in a certain range; the impact strength of PVC composite reaches to 60 kJ/m2, the tensile strength is about 37 Mpa, and then the elongation at break reaches to 65% while CPE and CaCO, has synergistic toughening effect on PVC.

  14. 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%.

  15. 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.

  16. 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.

  17. Influence of CaCO3 on explosion characteristics of coal consumed by industrial pulverized coal boiler%CaCO3对煤粉工业锅炉用煤爆炸特性影响研究

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    为研究CaCO3对煤粉工业锅炉用煤爆炸特性的影响,以20 L爆炸测试装置中所测数据为基础,对2种煤粉工业锅炉典型用煤-CaCO3混合体系的爆炸行为进行研究,探讨CaCO3对煤粉工业锅炉用煤爆炸特性影响规律.结果表明,挥发分对煤粉的最大爆炸压力和最大爆炸指数有较大的影响,挥发分高的煤粉,其最大爆炸压力Pmax、最大爆炸指数Kmax相应较大;煤粉-CaCO3混合体系的最大爆炸压力Pmax和最大爆炸指数Kmx随CaCO3混合比例的提高而下降,CaCO3混合比例越高,Pmax、Kmax降低越多;Kmax降低比例与CaCO3的掺混比例近似成正比,比例系数为1.23.煤粉中混入CaCO3可以降低粉尘爆炸的风险,CaCO3对煤粉爆炸的抑制效力与煤种挥发分和可燃基含量有关,挥发分高、可燃基低的煤,惰化作用明显.

  18. Application of PEI–K2CO3/AC for capturing CO2 from flue gas after combustion

    International Nuclear Information System (INIS)

    Highlights: • A novel PEI–K2CO3/AC sorbent was prepared with the co-impregnation method. • The coupling characteristics of PEI and K2CO3 in the sorbent are expounded. • Both PEI and K2CO3 contribute to the total CO2 capture capacity of PEI–K2CO3/AC. • PEI–K2CO3/AC presents high CO2 capture capacity and long-term stability. • PEI–K2CO3/AC should be considered as a new option for post-combustion CO2 capture. - Abstract: The capture of CO2 from flue gas after combustion using solid sorbents is one of the efficient options for reducing CO2 emissions from fossil fuel-fired power plants. To satisfy the requirement of large quantities flue gas treatment, the CO2 capture capacities of the solid sorbents must be focused on. In order to obtain a sorbent with high CO2 capture capacity, a novel PEI–K2CO3/AC sorbent was prepared by impregnating potassium carbonate (K2CO3) and polyethylenimine (PEI) on activated carbon (AC) in this work. The CO2 capture performance of this sorbent was investigated using a fixed bed reactor system. The CO2 capture capacity of PEI–K2CO3/AC with the total K2CO3 and PEI loadings of 50 wt% was measured as 3.60 mmol CO2/g under the condition of 60 °C, 8% CO2 + 10% H2O. In addition, this sorbent is proved to be regenerable and stable during 5 cycle CO2 sorption–desorption tests. Compared with K2CO3/AC (loading of 58 wt%) and PEI/AC (loading of 43 wt%), PEI–K2CO3/AC presents higher CO2 capture capacity and long-term stability. Therefore, PEI–K2CO3/AC should be considered as a new option for capturing CO2 from flue gas after combustion

  19. 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.

  20. 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.

  1. 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。

  2. 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

  3. 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

  4. 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.

  5. Preparation and characterization of electrospun poly(3-hydroxybutyrate-co-3-hydroxyvalerate) fibrous mats

    Science.gov (United States)

    Xu, Yongjing; Zou, Liming; Lu, Hongwei; Chen, Zailing

    2015-07-01

    Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), as a biodegradable polyester, was electrospun to obtain defect-free fibers with high surface-area-to-volume ratio. Several parameters such as solvent ratio, polymer concentration, applied voltage, flow rate, and tip-to-target distance were optimized to achieve defect-free morphology. The average diameter of the PHBV fibers was 1400 nm. In order to evaluate the final properties of PHBV nanofibers, the following characterization techniques were employed: scanning electron microscopy (SEM), Fourier transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy, uniaxial tensile tests and dataphysics instruments.

  6. 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.

  7. Sintering kinetics of MgCO3-TiO2 systems

    OpenAIRE

    Petrović V.

    2006-01-01

    Ceramic materials have been in use in many different areas of human well-being for a very long time. The most common way of obtaining this material is using the process of sintering. During mechanical activation inorganic materials are ground when the grain size reduced. The crystal structure distorts and also changes, leading some systems to a chemical reaction and formation of a new compound. In this work we explain the influence of mechanical activation on sintering kinetics in MgCO3-TiO2 ...

  8. 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.

  9. 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.

  10. 油田采出水中CaCO3成垢影响因素试验

    Institute of Scientific and Technical Information of China (English)

    余宏伟

    2009-01-01

    针对油田结垢严重的问题,采用X-射线衍射仪对垢样进行检测,考察了油田采出水中常见成分NaCl、KCl、Mg2+的浓度及温度等因素对CaCO3溶解度的影响,分析了这些因素对CaCO3成垢的影响规律,研究了超声波对CaCO3成垢的影响,绘制出各种条件下CaCO3的溶解度曲线。结果表明,油田垢物主要以CaCO3为主,温度是影响CaCO3结垢的重要因素,NaCl、KCl,Mg2+对CaCO3有一定的增溶作用,超声波能达到防垢的目的。

  11. 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.

  12. Mesoporous Co3O4 nanocrystals as an effective electro-catalyst for highly reversible Li-O2 batteries

    Science.gov (United States)

    Zeng, J.; Francia, C.; Amici, J.; Bodoardo, S.; Penazzi, N.

    2014-12-01

    Lithium-oxygen (Li-O2) battery is considered as one of the most promising technologies among various electrochemical energy systems, since it can offer much higher theoretical energy density than the conventional lithium-ion battery. However, a high voltage gap between charge and discharge significantly limits the round-trip efficiency and cycle stability of Li-O2 batteries. In the present work, mesoporous Co3O4 is simply prepared and studied as a catalyst in Li-O2 cells. The Co3O4 nanoparticles possesses a high specific surface area and a spinel crystalline structure. Cyclic voltammetries demonstrate that mesoporous Co3O4 catalyst enhances the kinetics for either oxygen reduction reaction (ORR) or oxygen evolution reaction (OER). Such excellent catalytic performance of Co3O4 could be associated with its larger surface area and 3D ordered mesoporous structure. The electrode with mesoporous Co3O4 exhibits a higher discharge capacity and lowers the over-potential for discharge process, compared with the pure carbon electrode. In Li-O2 cells, the Co3O4 cathodes show enhanced electrochemical performances, including a high round-trip efficiency and a prolonged cycle life. More than 65 stable cycles are observed with a Co3O4-catalyzed electrode, which could be attributed to the low recharge voltage, at which main side reactions due to decomposition of TEGDME-based electrolyte can be suppressed.

  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. 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.

  16. Synthesis and enhanced photoelectrocatalytic activity of p–n junction Co3O4/TiO2 nanotube arrays

    International Nuclear Information System (INIS)

    Highlights: ► Co3O4/TiO2 nanotube arrays (NTs) were prepared by an impregnating–deposition–decompostion method treatment. ► Co3O4/TiO2 NTs exhibit high photoelectrocatalytic (PEC) activity. ► The high PEC activity was attribute to the formation of p–n junction between Co3O4 and TiO2. - Abstract: Co3O4/TiO2 nanotube arrays (NTs) were prepared by depositing Co3O4 nanoparticles (NPs) on the tube wall of the self-organized TiO2 NTs using an impregnating–deposition–decompostion method. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV–vis absorption spectroscopy. The photoelectrocatalytic (PEC) activity is evaluated by degradation of methyl orange (MO) aqueous solution. The prepared Co3O4/TiO2 NTs exhibit much higher PEC activity than TiO2 NTs due to the p–n junction formed between Co3O4 and TiO2.

  17. PP/CaCO3复合材料的力学性能研究

    Institute of Scientific and Technical Information of China (English)

    张志洪

    2007-01-01

    通过采用熔融共混的方法制备了PP/CaCO3复合材料,然后对复合材料的力学性能进行分析,研究了微米级和纳米级CaCO3的表面处理、含量对PP/CaCO3复合材料力学性能的影响规律,并对此影响规律进行合理的解释。

  18. 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.

  19. Facile Synthesis of SrCO3-Sr(OH)2/PPy Nanocomposite with Enhanced Photocatalytic Activity under Visible Light

    OpenAIRE

    Alfredo Márquez-Herrera; Victor Manuel Ovando-Medina; Blanca Estela Castillo-Reyes; Martin Zapata-Torres; Miguel Meléndez-Lira; Jaquelina González-Castañeda

    2016-01-01

    Pyrrole monomer was chemically polymerized onto SrCO3-Sr(OH)2 powders to obtain SrCO3-Sr(OH)2/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(OH)2 nanoparticles wi...

  20. The Comparative Study of Electrochemical Capacitance Performance between Sulphur-Doped Co3O4 and CoS Anodes

    OpenAIRE

    Xu, Wei; Khan, M. A.; Chen, Jiahui; Long, Yongbing; Xu, Gui; Bai, Yu; Zhang, Xiaodong; Qiu, Zhenmin; Lin, Sennian; Fan, Donghua

    2016-01-01

    Anode materials with high capacitance performance are highly desirable for supercapacitors (SCs). In this work, nanomaterials cobalt sulfide (CoS), sulphur-doped Co3O4 (S-Co3O4), and Co3O4 were fabricated on a carbon cloth substrate by hydrothermal method. The composition and morphology of the material were characterized by X-ray diffraction (XRD) patterns and Scanning Electron Microscope (SEM). The electrochemical measurements were performed in a three-electrode system. The result shows that...

  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. 加工工艺对HDPE/CaCO3共混体系性能的研究%Study of processing on properties of HDPE/CaCO3 blends

    Institute of Scientific and Technical Information of China (English)

    李清江

    2016-01-01

    采用偏光显微镜研究了4种不同加工工艺对改性HDPE结晶结构的影响,并且通过SEM分析方法研究了纳米CaCO3在HDPE基体中的分散特性.研究结果表明:在HDPE/CaCO3共混体系配方不变的情况下,加工工艺d更有利于提高纳米CaCO3粒子在HDPE基体中的最终分散性和HDPE/CaCO3共混体系的力学性能.

  4. 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.

  5. Antibacterial characteristics of CaCO3-MgO composites

    International Nuclear Information System (INIS)

    Dentifrices, such as tooth-paste, are pastes containing insoluble abrasives that aid in the removal of plaque from the teeth and help to polish them. Composite powders contributing to oral hygiene application, i.e., nano-scale MgO crystallite dispersed in CaCO3 grain, were fabricated by the thermal decomposition of dolomite. The composite obtained by heating at 800 deg. C consisted of CaCO3 grains including 20 nm MgO fine crystallite, being the purpose powder in this study. The antibacterial activity of these powders related to gram-positive and gram-negative bacteria was evaluated in vitro. The thermal decomposition above 800 deg. C resulted in the mixture of CaO and MgO. Antibacterial activity of the composite enhanced with increasing powder concentration. Though antibacterial action toward Staphylococcus aureus was greater than towards Escherichia coli, the death rate constant was identical in both bacteria. It can be concluded that the obtained composite possesses two functions able to improve the oral hygiene: as a tooth abrasive and as an antibacterial agent.

  6. 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...

  7. Electrical conductivity measurement of MgCO3 up to 6 GPa and 1000 K

    Science.gov (United States)

    Mibe, K.; Ono, S.

    2012-04-01

    Magnesite, MgCO3, is a naturally occurring carbonate mineral and is stable over a wide range of pressure and temperature. It is known that magnesite is one of the important host phases of carbon in the Earth's deep interior. A knowledge of how magnesite's electrical properties vary as a function of pressure and temperature will be important in interpreting the observed electrical conductivity map of the Earth's interior. We, therefore, measured the electrical conductivity of polycrystalline magnesite at pressures 3-6 GPa at high temperatures using complex impedance spectroscopy in a multi-anvil high-pressure apparatus. Synthetic powdered magnesite (MgCO3)(purity > 99.5%) was used as the starting material. The measured electrical conductivity increased with increasing pressure. The activation enthalpy calculated in the temperature range 650-1000 K also increased with increasing pressure. The effect of pressure was interpreted as being the activation volume in the Arrhenius equation, and the fitted data gave an activation energy and volume of 1.76 ± 0.03 eV and -3.95 ± 0.78 cm3/mole, respectively. The negative activation volume and relatively large activation energy observed in this study suggests that the hopping of large polarons is the dominant mechanism for the electrical conductivity over the pressure and temperature range investigated.

  8. 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.

  9. A CO(3-2) survey of a merging sequence of luminous infrared galaxies

    CERN Document Server

    Leech, J; Papadopoulos, P P; Gao, Y; Davis, G R

    2010-01-01

    Luminous infrared galaxies ($L_{\\rm{IR}}>10^{11} L_{\\odot}$) are often associated with interacting galactic systems and are thought to be powered by merger--induced starbursts and/or dust--enshrouded AGN. In such systems, the evolution of the dense, star forming molecular gas as a function of merger separation is of particular interest. Here, we present observations of the CO(3-2) emission from a sample of luminous infrared galaxy mergers that span a range of galaxy-galaxy separations. The excitation of the molecular gas is studied by examining the CO(3-2)/CO(1-0) line ratio, $r_{31}$, as a function of merger extent. We find these line ratios, $r_{31}$, to be consistent with kinetic temperatures of $T_k$=(30--50) K and gas densities of $n_{\\rm{H}_2}=10^3 \\rm{cm}^{-3}$. We also find weak correlations between $r_{31}$ and both merger progression and star formation efficiency ($L_{\\rm{fIR}} / L_{\\rm{CO(1-0)}}$). These correlations show a tendency for gas excitation to increase as the merger progresses and the st...

  10. Labelling of central neural system receptor ligands with the fac-[Tc(CO)3]+ moiety

    International Nuclear Information System (INIS)

    During the period of the IAEA Co-ordinated Research Project on Development of Agents for the Imaging of CNS Receptors based on 99mTc, many efforts were made to find an improved system or alternative methods for the labelling of various central nervous system (CNS) receptor binding agents based on the fac-[Tc(CO)3]+ fragment. Within the same period the chemistry of the fac-[Tc(CO)3]+ fragment has been developed as a useful label more and more not only for the labelling of CNS receptor ligands but also for peptides, antibodies and other biologically active molecules such as B12. Especially the latter molecule is known to be taken up as well through the blood-brain barrier but is obviously not an CNS receptor ligand. One of the most important achievements over the whole period of the project has been the final formulation of a kit useful for the preparation of [99mTc(OH2)3(CO)3]+ without the requirement for using free CO. Much time was invested in that particular topic, since it will allow this relevant moiety to be applied not only on a routine basis but also for research into CNS ligands. A major achievement has thus been the commercial availability of these kits by the beginning of 2002. During the period of the project, a number of new systems were introduced, some of which were specially designed not only for CNS receptor ligands but also for other biomolecules. Among these is that for the syntheses of highly lipophilic ligands, the complex formation of which is based on classical co-ordination chemistry. In addition, the feasibility of the mixed ligand concept from a chemical point of view has been proved in principle. A number of complexes have been prepared where the CNS receptor ligand is attached to the monodentate ligand system. In principle it can also be attached to the bidentate moiety, allowing a screening of the biological behaviour as a function of the co-ligand. A major breakthrough could be achieved with the aqueous synthesis of cymantren

  11. Na2CO3和NaHCO3胁迫对菊苣种子萌发的影响%Effects of Na2CO3 and NaHCO3 Stress on Seed Germination of Chicory

    Institute of Scientific and Technical Information of China (English)

    郭丹丹

    2013-01-01

    [目的]为研究Na2CO3和NaHCO3等碱性盐对植物的胁迫伤害提供依据.[方法]用不同浓度的Na2CO3和NaHCO3溶液处理菊苣种子,并对其发芽率、发芽势、根长、苗长和鲜重等生理指标进行研究.[结果]低浓度Na2CO3和NaHCO3对萌发后菊苣的苗长、根长和鲜重有一定的促进作用,但对根苗比的影响表现为抑制.[结论]低浓度Na2CO3和NaHCO3对种子萌发有增效效应.%[Objective] The research aimed to provide the basis for the study of the damage of the stress of basic salt such as Na2CO3 and NaHCO3 on the plants.[Method] Chicory seeds were treated with Na2CO3 and NaHCO3 solution of different concentration.The physiological indicators such as germination rate,germination potential,root length,seedling length and fresh weight were studied.[Result] A low concentration of Na2CO3 and NaHCO3 could promote germination rate,germination potential,then promote seedling length,root length and fresh weight after germination.However,it showed the performance for suppression on the ratio of root and shoot.[Conclusion] A low concentration of Na2CO3 and NaHCO3 had synergistic effect on chicory seed germination rate and germination potential.

  12. 超细CaCO3的粒子尺寸对PP结晶行为的影响%INFLUENCE OF THE SIZE OF ULTRAFINE CaCO3 POWDER ON PP CRYSTALLIZATION

    Institute of Scientific and Technical Information of China (English)

    杨军; 刘万军; 陈广新; 刘景江

    2001-01-01

    The effects of CaCO3 on the crystallization behavior of polypropylene (PP) were studied by means of DSC and WAXD.The average sizes of the CaCO3 powders used were 0.1μm (UC) and 0.5μm (GC),respectively.The PP/CaCO3 composites at compositions of 1phr and 10 phr were investigated.The results showed that the addition of CaCO3 reduced the supercooling,the rate of nucleation and the overall rate of crystallization (except for the 10phr UC/PP sample).The crystallinity of PP was increased and the size distribution of the crystallites of α-PP was broadened.On the other hand,the crystallization rate of 10phr UC/PP is 1.5 times higher than that of neat PP.It has an overall rate of crystallization 2 times as much as that of the neat PP and has the maximum crystallinity.The sizes of crystallites and the unit cell parameters of α-PP were varied by the addition of CaCO3.β-PP was formed by addition of GC and was not detected by addition of UC.The differences of crystallization behaviors of PP might be attributed to the combined effects of the content and size of CaCO3 filled.

  13. Nano-Crystalline Co3O4 Spinel Prepared by Combustion Method as a Catalyst for Direct Decomposition of N2O

    Directory of Open Access Journals (Sweden)

    Makhlouf MT

    2015-12-01

    Full Text Available Combustion method has been used as a fast and facile method to prepare nano-crystalline Co3O4 spinel employing urea as a combustion fuel. Alkali-promoted catalysts were prepared by the incipient wetness impregnation of the prepared nano-material with the aqueous solutions of alkali carbonates (Li2CO3, Na2CO3, K2CO3, and Cs2CO3. N2O decomposition was investigated over pure and alkali promoted nano-crystalline Co3O4 catalysts. The beneficial influence of dopants on the catalyst activity increases in the order: un-promoted

  14. 双测定法评定石灰石中CaCO3含量

    Institute of Scientific and Technical Information of China (English)

    郭佺

    2001-01-01

    本文指出通过测定钙离子来换算成CaCO3含量这一方法有不妥之处,并提出用双测定法来评定石石中CaCO3含量。这一方法主要是在原测定方法的基础上,在对试样中CO2-3含量进行测定,根据CO2-3含量换算成CaCO3。然后对两种方法换算的CaCO3进行比较,取其最低值为最佳真实值。

  15. 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.

  16. Investigation of the sintering of barytocalcite with BaCO3 as a secondary phase for immobilizing carbon-14

    Science.gov (United States)

    Massoni, Nicolas; Le Gallet, Sophie

    2016-08-01

    The effect of a secondary phase (BaCO3) on the sintering of synthetic barytocalcite has been investigated. It was found that this phase impacts the sintering positively by lowering the sintering activation energy from 230 to 160 kJ mol-1, by increasing the shrinkage rate and by reaching higher densities. However, BaCO3, originally dispersed in the powder, was segregated by diffusion during sintering with a large part of it being located at the grain boundaries. The dense pellet is made of both phases barytocalcite and BaCO3, what should be avoided to give the best leaching resistance. Thus the BaCO3 presence should be limited as much as possible by controlling the reactants stoichiometry during the synthesis.

  17. Urchin-like Co3O4 Nanostructure and Their Electrochemical Behavior in Rechargeable Lithium Ion Battery

    Institute of Scientific and Technical Information of China (English)

    Hui Li; Guang Tao Fei; Ring Cui; Yi Jin; Xu-yong Feng; Chun-hua Chen

    2011-01-01

    3D urchin-like Co3O4 have been successfully prepared by calcination of the urchin-like precursors, which were synthesized through a facile hydrothermal route. The morphology and structure of the 3D urchin-like Co3O4 have been characterized by field emission scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy, and X-ray powder diffraction. The as-synthesized Co3O4 products are of urchin-like structures with approximated 5-7 μm in diameter, and are composed of numerous nanoparticles chains with the parzicles diameter of about 15 nm. This kind of urchin-like Co3O4 exhibits superior energy storage properties with the high capacity of 1.369 Ah/g and its good cyclic stability shows great potential in the rechargeable Li-ion battery.

  18. 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....

  19. Synthesis and formation mechanism of micro/nano flower-like MgCO3·5H2O

    Science.gov (United States)

    Yin, Wan-zhong; Wang, Yu-lian; Ji, Qiang-dong; Yao, Jin; Hou, Ying; Wang, Lei; Zhong, Wen-xing

    2014-03-01

    Micro/nano magnesium carbonate pentahydrate (MgCO3·5H2O) with flower-like morphology was synthesized using magnesite as a substrate and potassium dihydrogen phosphate as an additive. The synthesized samples were characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetry and differential scanning calorimetry. The influence of pyrolysis time on crystal morphology was explored. The formation mechanism was investigated on the basis of the characterized results and the crystal structure of MgCO3·5H2O. The results showed that the flower-like MgCO3·5H2O was 1.5-3.0 μm in length and 100-500 nm in diameter and was successfully obtained with a pyrolysis time of 30 min. The formation mechanism of flower-like MgCO3·5H2O is suggested to be the selective adsorption of potassium dihydrogen phosphate on the surface. The process of flower-like crystal growth is as follows: amorphous nanoparticles formation, acicular and rod monocrystal formation, flower-like monocrystal formation, and flower-like polymers (MgCO3·5H2O) crystallization. In the MgCO3·5H2O crystal, the magnesium ion presents two different octahedral coordinations corresponding to Mg(H2O){6/2-} and [Mg(H2O) (CO{3/2-})2]2-, and the chemical formula of the crystal is Mg(H2O)6 · Mg(H2O)4 (CO{3/2-})2.

  20. Template-free synthesis of hierarchical porous Co3O4 microspheres and their application for electrochemical energy storage

    International Nuclear Information System (INIS)

    Graphical abstract: We report a facile template-free chemical bath deposition method for the growth of Co3O4 nanoflake microspheres and demonstrate noticeable electrochemical properties with higher capacities and better cycling life than the nanowire counterparts. Display Omitted -- Highlights: •Construct Co3O4 nanoflake microspheres by a template-free method. •Co3O4 nanoflake microspheres show high capacity and good cycling life. •Nanoflake microspheres are favorable for fast ion and electron transfer. -- Abstract: Tailored high-activity cathode materials are of great importance for construction of high-performance capacitors and hybrid batteries. In this work, we report a facile template-free chemical bath deposition method to fabricate porous Co3O4 nanoflake microspheres consisting of self-assembled nanoflakes with thicknesses of ∼10 nm. The as-prepared Co3O4 microspheres have average diameters of ∼2 μm and the secondary Co3O4 nanoflakes are interconnected with each other forming a highly open net-structure with pore diameters of 20-200 nm. When evaluated as cathode materials for pseudocapacitive hybrid batteries, the Co3O4 nanoflake microspheres deliver a specific capacity of 83 mAh g−1 at 1 A g−1 after 10,000 cycles, higher than the Co3O4 nanowire microspheres counterpart (70 mAh g−1). In addition, the electrode exhibits excellent long-term cycling stability with 94.5% capacity retention after 10,000 cycles at 1 A g−1. The enhancement of high-rate electrochemical performances is due to the unique nanoflake microspheres architecture with large surface area and open porous structure

  1. Prevalence and behavioural risks for HIV and HCV infections in a population of drug users of Dakar, Senegal: the ANRS 12243 UDSEN study

    Science.gov (United States)

    Leprêtre, Annie; Ba, Idrissa; Lacombe, Karine; Maynart, Maryvonne; Toufik, Abdalla; Ndiaye, Ousseynou; Kane, Coumba Toure; Gozlan, Joël; Tine, Judicaël; Ndoye, Ibrahim; Raguin, Gilles; Girard, Pierre-Marie

    2015-01-01

    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 determinant was

  2. 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

  3. 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.

  4. 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。

  5. CaCO3/CPE/PP三元复合材料的性能研究

    Institute of Scientific and Technical Information of China (English)

    周松; 张炜; 简思强; 廖强; 易锋

    2009-01-01

    分别研究了CPE和SBS对聚丙烯性能的影响,CPE使PP的熔融指数略有下降,CPE含量为10%时,CPE/PP的冲击和拉伸强度分别比纯聚丙烯提高了108%和12%;进一步研究了微米CaCO3和纳米CaCO3对CPE/PP复合材料性能的影响,微米CaCO3使CPE/PP的拉伸强度提高,但冲击强度降低;纳米CaCO3对CPE/PP同时具有增强和增韧作用,当纳米CaCO3含量为8%时,CaCO3/CPE/PP三元复合材料的综合力学性能较好。

  6. 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.

  7. 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.

  8. 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.

  9. 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)). PMID:27080890

  10. 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.

  11. UV-Ozone Treatment on Cs2CO3 Interfacial Layer for the Improvement of Inverted Polymer Solar Cells

    International Nuclear Information System (INIS)

    Inverted configuration polymer solar cells (IPSCs) were prepared by using Cs2CO3 modified indium tin oxide (ITO) substrates as cathode and MoO3/Al as anode, ITO/Cs2CO3/P3HT:PCBM/MoO3/Al. The interfacial Cs2CO3 layers were conducted with annealing treatment and different time UV-Ozone treatment. The power conversion efficiency (PCE) of IPSCs was improved to 1% when the UV-Ozone treatment time is 15 minutes, with the open-circuit voltage of 0.48 V, short-circuit current density of 5.4 mA/cm2, and fill factor of 39%. The improvement of IPSCs should be attributed to the increased electron transporting and collection ability of Cs2CO3 layer induced by UV-Ozone treatment. The underlying mechanism of PCE improvement was discussed in terms of series and shunt resistance of cells induced by UV-Ozone treatment on Cs2CO3 layer, and the mole ratio of Cs to O of Cs2CO3 layer with different UV-Ozone treatment was investigated by scanning electron microscopy operating in the mode for in situ energy dispersive X-ray (EDX) spectra.

  12. 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.

  13. 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.

  14. How to control the scaling of CaCO3: a "fingerprinting technique" to classify additives.

    Science.gov (United States)

    Verch, Andreas; Gebauer, Denis; Antonietti, Markus; Cölfen, Helmut

    2011-10-01

    A titration set-up coupling ion selective electrodes with pH adjustment was used to analyze the effects of additives present during precipitation of calcium carbonate. Besides industrially well-established antiscalants (sodium triphosphate, citrate, polyacrylate and poly(aspartic acid)), also functional polymers being active in morphosynthesis (polystyrene sulfonate and poly(styrene-alt-maleic acid)) were analyzed. Interestingly each additive acts in its specific way, suggesting the notation "fingerprinting" for a complex interplay of up to five "solution modes" of influencing CaCO(3) precipitation and crystallisation. The results provide new insights into the modes of additive controlled crystallisation, and in the long run, the insights may facilitate the design of precipitation systems that yield complex and tailor-made crystals. PMID:21860865

  15. Electrical conductivity of MgCO 3 at high pressures and high temperatures

    Science.gov (United States)

    Mibe, Kenji; Ono, S.

    2011-05-01

    The electrical conductivity of polycrystalline magnesite (MgCO 3) was measured at 3-6 GPa at high temperatures using complex impedance spectroscopy in a multi-anvil high-pressure apparatus. The electrical conductivity increased with increasing pressure. The activation enthalpy calculated in the temperature range 650-1000 K also increased with increasing pressure. The effect of pressure was interpreted as being the activation volume in the Arrhenius equation, and the fitted data gave an activation energy and volume of 1.76±0.03 eV and -3.95±0.78 cm 3/mole, respectively. The negative activation volume and relatively large activation energy observed in this study suggests that the hopping of large polarons is the dominant mechanism for the electrical conductivity over the pressure and temperature range investigated.

  16. Post-perovskite MgCO3 phase at pressures up to 800 GPa

    Science.gov (United States)

    Tsz-Kai Wan, Jones

    2008-03-01

    The high-pressure phases of magnesite (MgCO3) are investigated by variable cell first-principles molecular dynamics simulations. At pressures compatible to lower mantle conditions (˜120 GPa), the carbon atoms are surrounded by 4 oxygen atoms, which is consistent with the work of Skorodumova et al. (2005). Perovskite phase is observed at pressures greater than 300 GPa, but its stability is still subject to further studies. Stable post-perovskite structure is observed at pressures up to 800 GPa, and is found to be more stable than the perovskite phase. The results may bring important implications to interior models of giant planets, which may lead to a better understanding in giant planets physics.

  17. Melting and decomposition of MgCO3 at pressures up to 84 GPa

    Science.gov (United States)

    Solopova, N. A.; Dubrovinsky, L.; Spivak, A. V.; Litvin, Yu. A.; Dubrovinskaia, N.

    2015-01-01

    Magnesium carbonate MgCO3 (magnesite) was experimentally studied at pressures of 12-84 GPa and temperatures between 1,600 and 3,300 K. We applied the high-pressure technique using a multianvil press and a diamond anvil cell with laser heating. The phase relations and melting of magnesite were investigated by means of Raman and time-resolved multi-wavelength spectroscopy. Magnesite is found to melt congruently within the entire studied pressure range at temperatures of 2,100-2,650 K. At temperatures above 2,700 K, we observed decomposition of magnesite with formation of MgO and a carbon phase (diamond). Our results demonstrate that at high pressures, the magnesium carbonate melt can exist at a wide range of thermodynamic conditions.

  18. 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.

  19. 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.

  20. 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.

  1. Crystal field and magnetization of canted antiferromagnet CoCO3

    Science.gov (United States)

    Meshcheryakov, V. F.

    2007-11-01

    The magnetization of the canted antiferromagnet CoCO3 ( T N = 18.1 K) is calculated in the Weiss molecular field approximation taking into account the microscopic state of the Co2+ ion in the entire range of temperatures and magnetic fields. The values of T N, magnetic susceptibility in the basal plane, and ferromagnetic moment were used as parameters. It is shown that the anisotropy of the g factor and of the exchange interaction at low temperatures ( T < 30 K) including the magnetic ordering temperature is correctly described in the Abragam-Pryce approximation. At high temperatures, the g factor increases and becomes isotropic, but it cannot be described using the Abragam-Pryce approximation. The reasons for g factor variation and the magnitude of the magnetic moment are discussed.

  2. Magnetization of the canted antiferromagnetic CoCO 3 in Abragam-Pryce approximation

    Science.gov (United States)

    Meshcheryakov, V. F.

    2006-05-01

    Weiss molecular field theory was used to calculate the magnetization of the canted antiferromagnetic CoCO 3 ( T=18.1 K). Wave functions of magnetic doublets near Co 2+ ground state in Abragam-Pryce approximation were determined. One of the crystal field variables, free Co 2+ ion isotropic exchange interaction inside, and between magnetic sublatticies, and rotation angle ϕ, characterizing nonequivalence ion Co 2+ positions, were used as parameters. From comparison with the experimental data exchange interaction anisotropy and g-factors g, g were obtained. At low temperatures T<40 K the coincidence of calculated and experimental results are good and g-factor values are almost the same as have been obtained from EPR data in Co(1%)+CdCO single crystals. At high temperatures in the paramagnetic region, experimental data differs from calculated ones by more than two times. It is shown that this discrepancy cannot be described within the frames of used approximations.

  3. 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.

  4. K2CO3 catalysis on the reactivity of top charged coke and stamp charged coke

    Science.gov (United States)

    Pang, Qing-hai; Zhang, Jian-liang; Qi, Cheng-lin; Ma, Chao; Kong, De-wen; Mao, Rui

    2013-01-01

    The catalysis of K2CO3 on the reactivity of top charged coke and stamp charged coke from Pansteel in China was studied. The coke reaction index of the stamp charged coke was 1%-2% higher than that of the top charged coke. Under the catalysis of K2CO3, the coke reaction index of both cokes approximately increased by 4%, 6%, 10% and 6% at 900, 1000, 1100 and 1200°C, respectively. The reactivity of the K-enriched stamp charged coke was 1%-2% higher than that of the K-enriched top charged coke below 1100°C. However, only negligible differences were found in the temperature zone between 1100 and 1200°C. Scanning electron microscopy images illustrated that pores in the top charged coke were smaller and equally distributed, while relatively more big pores exist non-homogenously in stamp charged coke. Due to the different processes in production, the stamp charged coke was more porous and most of the pores tended to be applanate. Cracks were observed in the microstructure of the stamp charged coke during the carbon solution reaction, implying the inferior quality of the stamp charged coke to the top charged coke at high temperature. Diffusion of K during the carbon solution reaction was studied by the energy dispersive spectrometry. It is found that K gradually spreads into the center of lumpy coke with the rising of temperature and is equally distributed on the edges of pores at 1200°C. Besides, oxidation reactions of functional groups become faster with the catalysis of K.content

  5. 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.

  6. 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.

  7. Reduced Graphene Oxide: Is it a promising catalyst for the electrochemistry of [UO2(CO3)3]4−/[UO2(CO3)3]5−?

    International Nuclear Information System (INIS)

    Highlights: • First report on aqueous electrochemistry of uranium on graphene materials. • Graphene(Nafion)/GC did not show applicability for the anionic analytes. • Electrochemically Reduced Graphene Oxide (ERGNO) was synthesised by cyclic voltammetry. • ERGNO catalysed the electrochemistry of [UVIO2(CO3)3]4-/[UVO2(CO3)3]5-. • Both the cathodic and anodic overpotentials of U(VI)/U(V) reaction decreased on ERGNO. - Abstract: The graphene has been emerging in the electrocatalysis and electroanalysis as the potent surface modifying agents for the working electrodes. However, the aqueous electrochemistry of the actinides on graphene (or graphene type materials) is yet unexplored. In this paper, the aqueous electrochemistry of [UVIO2(CO3)3]4−/[UVO2(CO3)3]5− redox couple was systematically investigated on electrochemically reduced graphene oxide (ERGNO) modified glassy carbon (GC) electrode in saturated Na2CO3 solution (pH ∼12.3). This is the first report on aqueous actinide electrochemistry on graphene materials. The results showed that ERGNO could catalyse the redox chemistry of [UVIO2(CO3)3]4−/[UVO2(CO3)3]5− by reducing both the cathodic and anodic overpotentials compared to bare GC electrode. However, no enhancement in the peak current was observed on ERGNO electrode for the same reaction. Therefore, the present study introduces an appeal for a systematic investigation on the electrochemistry of the actinides at graphene materials to gear up their applications in nuclear technology

  8. SYNTHESIS AND CHEMICAL BEHAVIOR OF THE [CO3NI7(CO)16C2]2- AND [CO3NI7(CO)15C2]3- DICARBIDE CLUSTERS - X-RAY CRYSTAL-STRUCTURE OF [PPH4]2[CO3NI7(CO)16C2

    OpenAIRE

    Arrigoni, A; A. Ceriotti; DELLA PERGOLA, R; LONGONI, G; M. Manassero; Sansoni, M

    1985-01-01

    The synthesis and properties of the new dicarbidocarbonyl bimetallic clusters [Co3Ni7(CO)16C2]2- and [Co3Ni7(co)15C2]3- are described. Anion I is paramagnetic, and has a metal frame based on a 3,4,3-C2h stack of metal atoms. The resulting deca-vertces metal polyhedron encapsulates a c2 fragment showing a short C-C interatomic separation of 1.48 Å

  9. Sonochemical method for synthesizing Co3O4/graphene nanocomposites for use as counter electrode in dye-sensitized solar Cells

    Science.gov (United States)

    Kamar, E. M.; Reda, S. M.

    2016-07-01

    Co3O4/graphene nanocomposites were synthesized via sonochemical method, and its application as a counter electrode (CE) for dye-sensitized solar cell (DSSC) was demonstrated. The prepared Co3O4/graphene nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, and UV-Vis absorption spectroscopy. The results of SEM showed that Co3O4 nanoparticles deposited on the graphene sheets as spacers to keep the neighboring sheets separated. The Co3O4 have diameters ranging from 16 to 43 nm. The influence of the Co3O4 content on the photovoltaic performance of dye-sensitized solar cell was investigated. It was found that the performances of Co3O4/graphene composites are better than that of graphene-based DSSCs. The Co3O4/graphene composite CE with 80 % Co3O4 content exhibits the best conversion efficiency (PCE) of 2.1 %.

  10. The Effect of Al and Fe on the Intergranular Embrittlement of Co3Ti Alloys by Hydrogen Transport from the External Surface

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Some observation relating to the solubility, diffusivity and intergranular cracking by hydrogen transport from the external surface in Co3Ti, Co3Ti-Al and Co3Ti-Fe alloys have been carried out. The results show that the addition of alloying elements Al or Fe to Co3Ti alloy can increase the critical hydrogen concentration for changing from transgranular to brittle intergranular fracture, therefore suppress the moisture induced environmental embrittlement.

  11. Effect of CaCO3 Content on Mechanical Properties of PE-HD/CF Composites%纳米CaCO3对PE-HD/CF复合材料力学性能的影响

    Institute of Scientific and Technical Information of China (English)

    黄虹; 王选伦; 明浩

    2014-01-01

    针对高密度聚乙烯(PE-HD)/碳纤维(CF)二元复合材料随CF含量的增加,拉伸强度和弯曲强度增大、冲击强度却逐渐下降的情况,在二元体系中添加纳米CaCO3制得PE-HD/CF/CaCO3三元复合材料,对比分析了两种复合材料的力学性能,并采用扫描电子显微镜对三元复合材料的冲击断面进行观察。结果表明,纳米CaCO3的加入使得三元复合材料的拉伸强度略有降低,但弯曲强度和冲击强度在一定范围内增大;当纳米CaCO3含量为10份时,复合材料的综合力学性能最佳。%With the increase of carbon fiber(CF) content in PE-HD/CF composites,the tensile strength and bending strength increased,but the impact strength decreased gradually.To overcome the defect,PE-HD/CF composites was blended with nanometer CaCO3,so PE-HD/CF/CaCO3 ternary composites were obtained.The mechanical properties of PE-HD/CF composites and PE-HD/CF/CaCO3 were analyzed,and the impact fracture surface of ternary composites was observed by SEM. The results showed that the tensile strength of PE-HD/CF/CaCO3 ternary composites reduced slightly than the binary composites,but the bending strength and impact strength increased in a certain range.The ternary composites had the best mechanical properties when nanometer CaCO3 content was 10phr.

  12. Research of Methods of PPW Coating on the Surface of Nano-CaCO3%纳米CaCO3表面包覆PPW方法的探讨

    Institute of Scientific and Technical Information of China (English)

    王剑峰; 生瑜

    2008-01-01

    先用丙烯酸(AA)处理CaCO3,在其表面引入活性双键基团后,再通过表面包覆反应将低分子量PP(PPW)固定在CaCO3表面.实验发现改性纳米CaCO3可经受甲苯、稀盐酸处理而不发生溶解,证明PPW已经通过化学键合而成功地包覆在CaCO3表面.估算了PPW的理论用量为纳米CaCO3的8.86wt%:并比较了不同包覆反应方法对包覆率的影响,发现干法相对其他方法在工艺及包覆效果上均有优势.

  13. Adsorption of Cd(II) by Mg-Al-CO3- and magnetic Fe3O4/Mg-Al-CO3-layered double hydroxides: Kinetic, isothermal, thermodynamic and mechanistic studies.

    Science.gov (United States)

    Shan, Ran-ran; Yan, Liang-guo; Yang, Kun; Hao, Yuan-feng; Du, Bin

    2015-12-15

    Understanding the adsorption mechanisms of metal cations on the surfaces of solids is important for determining the fate of these metals in water and wastewater treatment. The adsorption kinetic, isothermal, thermodynamic and mechanistic properties of cadmium (Cd(II)) in an aqueous solution containing Mg-Al-CO3- and magnetic Fe3O4/Mg-Al-CO3-layered double hydroxide (LDH) were studied. The results demonstrated that the adsorption kinetic and isotherm data followed the pseudo-second-order model and the Langmuir equation, respectively. The adsorption process of Cd(II) was feasible, spontaneous and endothermic in nature. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy were used to explain the adsorption mechanisms. The characteristic XRD peaks and FTIR bands of CdCO3 emerged in the LDH spectra after Cd(II) adsorption, which indicated that the adsorption of Cd(II) by LDHs occurred mainly via CdCO3 precipitation, surface adsorption and surface complexation. Furthermore, the magnetic Fe3O4/Mg-Al-CO3-LDH can be quickly and easily separated using a magnet before and after the adsorption process. PMID:26073520

  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. 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.

  16. 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...

  17. 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.

  18. Production and Utilization of CO3- Produced by a Corona Discharge in Air for Atmospheric Pressure Chemical Ionization

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, Robert G.; Waltman, Melanie J.

    2010-12-14

    Atmospheric pressure chemical ionization is a multistep ionization process used in mass spectrometry and ion mobility spectrometry. The formation of product ions depends upon interactions with the analyte and the reactant ion species formed in the ionization source. The predominant reactant ion observed in a point-to-plane corona discharge in air occurs at m/z 60. There have been multiple references in the literature to the identity of this ion with some disagreement. It was postulated to be either CO3- or N2O2-. The identity of this ion is important as it is a key to the ionization of analytes. It was determined here to be CO3- through the use of 18O labeled oxygen. Further confirmation was provided through MS/MS studies. The ionization of nitroglycerine (NG) with CO3- produced the adduct NG•CO3-. This was compared to ionization with NO3- and Cl- reactant ions that also formed adducts with NG. The fragmentation patterns of these three adducts provides insight into the charge distribution and indicates that CO3- has a relatively high electron affinity similar to that of nitrate.

  19. Effects of Soil Texture and CaCO3 on Turnover of Organic Material in Chao Soils

    Institute of Scientific and Technical Information of China (English)

    SUNBO; LINXIN-XIONG

    1993-01-01

    Decomposition experiments of 14C-labelled sickle alfalfa in chao soils of different texture and these soils after removal of CaCO3 were carried out under field and laboratory conditions respectively.The amount of residual 14C in,or 14CO2 evolved from,the soils at intervals after the beginning of devomposition were measured and the distribution of native and labelled C between particle size fractions isolated from these soils was edtermined.Results showed that contents of both labelled (14C) and non-labelled (12C) carbon decreased with increasing particle size.The enrichment factor for 14C was higher than that for 12C in the clay fraction,the reverse being true for the silt enrichment factors.The effect of soil texture on the decomposition of plant material could not be observed in chao soils when the clay content was lower than 270g kg-1,while it became obvious once CaCO3 was removed was correlated from these soils.The decomposition rate of plant material in the soil from which the native CaCO3 Was removed was correlated significantly to both the clay content of the soil and the application rate of CaCO3.A preliminary correction equation describing the effect of clay and CaCO3 on the decomposition of organic material in chao soil was derived from the results obtained.

  20. A novel synthesis of SrCO3–SrTiO3 nanocomposites with high photocatalytic activity

    International Nuclear Information System (INIS)

    The results of the production and characterization of SrCO3–SrTiO3 nanocomposites as a promising candidate for efficient photocatalysts are reported. The production is based on a novelty route employing the solvothermal method with strontium chloride and titanium (IV) butoxide as the precursor solutions. The effect on the properties of the nanocomposites due to changes in the content of SrCO3 and SrTiO3 is reported. The as-prepared materials were tested in the photodegradation of methylene blue dye in aqueous solutions under the solar light. The reported route allows the production of SrCO3–SrTiO3 nanocomposites with particle sizes ranging between 18 and 29 nm. The SrCO3–SrTiO3 nanocomposites obtained with 19 % of SrCO3 phase and 81 % of SrTiO3 (M10) can achieve 94 and 97 % of dye photodegradation after 30 and 120 min, respectively

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Fabrication, modification and application of (BiO)2CO3-based photocatalysts: A review

    Science.gov (United States)

    Ni, Zilin; Sun, Yanjuan; Zhang, Yuxin; Dong, Fan

    2016-03-01

    (BiO)2CO3 (BOC), a fascinating material, belongs to the Aurivillius-related oxide family with an intergrowth texture in which Bi2O22+ layers and CO32- layers are orthogonal to each other. BOC is a suitable candidate for various fields, such as healthcare, photocatalysis, humidity sensor, nonlinear optical application and supercapacitors. Recently, the photocatalysis properties of (BiO)2CO3 have been gained increased attention. BOC has a wide band gap (3.1-3.5 eV), which constrains its visible light absorption and utilization. In order to enhance the visible light driven photocatalytic performance of BOC, many modification strategies have been developed. According to the discrepancies of different coupling mechanisms, six primary systems of BOC-based nanocomposites can be classified and summarized: namely, metal/BOC heterojunction, single metal oxides (metal sulfides)/BOC heterostructure, bismuth-based metallic acid salts (BixMOy)/BOC, bismuth oxyhalides (BiOX)/BOC, metal-free semiconductor/BOC and the BOC-based complex heterojunction. Doping BOC with nonmetals (C, N and oxygen vacancy) is unique strategy and warrants a separate categorization. In this review, we first give a detailed description of the strategies to fabricate various BOC micro/nano structures. Next, the mechanisms of photocatalytic activity enhancement are elaborated in three parts, including BOC-based nanocomposites, nonmetal doping and formation of oxygen vacancy. The enhanced photocatalytic activity of BOC-based systems can be attributed to the unique interaction of the p-n junction (semiconductor/semiconductor heterostructures), the Schottky junction (metal/semiconductor heterostructures), the surface plasmon resonance (SPR) effect, the surface scattering and reflecting (SSR) effect, the well-matched band structures, tunable electronic band structure, photosensitization and excellent electronic conductivity. Besides, multi-functional applications of BOC based materials are presented. Finally

  6. 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.

  7. Electron energy-loss spectroscopic tomography of FexCo(3-x)O4 impregnated Co3O4 mesoporous particles: unraveling the chemical information in three dimensions.

    Science.gov (United States)

    Yedra, L; Eljarrat, A; Arenal, R; López-Conesa, L; Pellicer, E; López-Ortega, A; Estrader, M; Sort, J; Baró, M D; Estradé, S; Peiró, F

    2016-08-01

    Electron energy-loss spectroscopy-spectrum image (EELS-SI) tomography is a powerful tool to investigate the three dimensional chemical configuration in nanostructures. Here, we demonstrate, for the first time, the possibility to characterize the spatial distribution of Fe and Co cations in a complex FexCo(3-x)O4/Co3O4 ordered mesoporous system. This hybrid material is relevant because of the ferrimagnetic/antiferromagnetic coupling and high surface area. We unambiguously prove that the EELS-SI tomography shows a sufficiently high resolution to simultaneously unravel the pore structure and the chemical signal. PMID:27314942

  8. 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.

  9. Several novel N-donor tridentate ligands formed in chemical studies of new fac-Re(CO)3 complexes relevant to fac-99mTc(CO)3 radiopharmaceuticals: attack of a terminal amine on coordinated acetonitrile.

    Science.gov (United States)

    Perera, Theshini; Marzilli, Patricia A; Fronczek, Frank R; Marzilli, Luigi G

    2010-03-01

    To evaluate syntheses of fac-[Re(CO)(3)L](+) complexes in organic solvents, we treated fac-[Re(CO)(3)(CH(3)CN)(3)]PF(6)/BF(4) in acetonitrile with triamine ligands (L). When L had two primary or two tertiary terminal amine groups, the expected fac-[Re(CO)(3)L](+) complexes formed. In contrast, N,N-dimethyldiethylenetriamine (N,N-Me(2)dien) formed an unusual compound, fac-[Re(CO)(3)(DAE)]BF(4) {DAE = (Z)-N'-(2-(2-(dimethylamino)ethylamino)ethyl)acetimidamide = (Me(2)NCH(2)CH(2))NH(CH(2)CH(2)N=C(NH(2))Me)}. DAE is formed by addition of acetonitrile to the N,N-Me(2)dien terminal primary amine, converting this sp(3) nitrogen to an sp(2) nitrogen with a double bond to the original acetonitrile sp carbon. The three Ns bound to Re derive from N,N-Me(2)dien. The pathway to fac-[Re(CO)(3)(DAE)]BF(4) is suggested by a second unusual compound, fac-[Re(CO)(3)(MAE)]PF(6) {MAE = N-methyl-N-(2-(methyl-(2-(methylamino)ethyl)amino)ethyl)acetimidamide = MeN(H)-CH(2)CH(2)-N(Me)-CH(2)CH(2)-N(Me)-C(Me)=NH}, isolated after treating fac-[Re(CO)(3)(CH(3)CN)(3)]PF(6) with N,N',N''-trimethyldiethylenetriamine (N,N',N''-Me(3)dien). MAE chelates via a terminal and a central sp(3) N from N,N',N''-Me(3)dien and via one sp(2) NH in a C(Me)=NH group. This group is derived from acetonitrile by addition of the other N,N',N''-Me(3)dien terminal amine to the nitrile carbon. This addition creates an endocyclic NMe group within a seven-membered chelate ring. The structure and other properties of fac-[Re(CO)(3)(MAE)]PF(6) allow us to propose a reaction scheme for the formation of the unprecedented DAE ligand. The new compounds advance our understanding of the spectral and structural properties of Re analogues of (99m)Tc radiopharmaceuticals. PMID:20104873

  10. 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.

  11. 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.

  12. 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.

  13. 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...... K, the Tg drops by 120 K, indicating that the reaction between Na2CO3 and glass is very fast. Increasing treatment duration causes a slight increase of Tg likely due to both a more homogeneous Na distribution and the compositional change of the glass as a result of Na2SrSi2O6 crystal formation....

  14. Novel Co3O4 porous polyhedrons derived from metal-organic framework toward high performance for electrochemical energy devices

    Science.gov (United States)

    Chen, Youcun; Hu, Lin

    2016-07-01

    Co3O4 polyhedrons with porous structure have been synthesized simply by annealing Prussian blue analogue (PBA) Co3[Co(CN)6]2 polyhedrons at 400 °C in air. The product was characterized by a series of techniques, such as X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), High-resolution TEM (HRTEM), X-ray Photoelectron Spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) gas adsorption. Interestingly, when evaluated as an anode material for lithium-ion batteries (LIBs), the Co3O4 porous polyhedrons manifested high reversible capacity (about 1200 mAh g-1 at 50 mA g-1) and excellent cycling performance. Moreover, they also exhibited a high specific capacitance of 110 Fg-1 when used as an electrode in the supercapacitor. It is suggested that the special morphology and porous nanostructure lead to the promising electrochemical properties.

  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. 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.

  17. 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.

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

    Science.gov (United States)

    Liu, Xiao-Bin; Wu, Lin-Ping; Hou, Jing; Chen, Jun-Yu; Han, Jing; Xiang, Hua

    2016-08-01

    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-produced PHBHV films, with 10~60 mol% 3-hydroxyvalerate (3HV) composition and different microchemical structures, was studied in nutrition-depleted activated sludge. The changes in mass, molar mass, chemical composition, thermal properties, and surface morphology were monitored. The mass and molar mass of each film decreased significantly, while the PHA monomer composition remained unchanged with time. Interestingly, the sample of random copolymer PHBHV-2 (R-PHBHV-2) (3HV, 30 mol%) had the lowest crystallinity and was degraded faster than R-PHBHV-3 containing the highest 3HV content or the higher-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 of films was confirmed by scanning electron microscopy. The dominant bacteria probably responsible for the degradation process were identified in the activated sludge. It was inferred that the degradation rate of haloarchaea-produced PHBHV films mainly depended on sample crystallinity, which was determined by monomer composition and microchemical structure and in turn strongly influenced surface morphology. PMID:27098259

  19. An unaccounted fraction of marine biogenic CaCO3 particles.

    Directory of Open Access Journals (Sweden)

    Mikal Heldal

    Full Text Available Biogenic production and sedimentation of calcium carbonate in the ocean, referred to as the carbonate pump, has profound implications for the ocean carbon cycle, and relate both to global climate, ocean acidification and the geological past. In marine pelagic environments coccolithophores, foraminifera and pteropods have been considered the main calcifying organisms. Here, we document the presence of an abundant, previously unaccounted fraction of marine calcium carbonate particles in seawater, presumably formed by bacteria or in relation to extracellular polymeric substances. The particles occur in a variety of different morphologies, in a size range from 100 µm, and in a typical concentration of 10(4-10(5 particles L(-1 (size range counted 1-100 µm. Quantitative estimates of annual averages suggests that the pure calcium particles we counted in the 1-100 µm size range account for 2-4 times more CaCO(3 than the dominating coccolithophoride Emiliania huxleyi and for 21% of the total concentration of particulate calcium. Due to their high density, we hypothesize that the particles sediment rapidly, and therefore contribute significantly to the export of carbon and alkalinity from surface waters. The biological and environmental factors affecting the formation of these particles and possible impact of this process on global atmospheric CO(2 remains to be investigated.

  20. 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.

  1. A study on thermal behaviour of HDPE/CaCO3 nanocomposites

    Directory of Open Access Journals (Sweden)

    S.M. Zebarjad

    2006-04-01

    Full Text Available Purpose: In order to improve physical and mechanical properties of high density polyethylene (HDPE addition of filler, rigid particles and even elastomer to HDPE is very common. One of the most important filler which is added to it is nano size calcium carbonate (CaCO3. To avoid agglomeration of nano size calcium carbonate addition of fatty acids such as stearic acid is very common.Design/methodology/approach: In the current study, nanocomposites with 10vol% nano size calcium carbonate were prepared. To investigate the role of stearic acid on nanocomposite behaviour, nanoparticles were coated at different stearic acid content. Thermal behaviour of high density polyethylene and its nanocomposites reinforced with both uncoated and coated calcium carbonate were investigated. For this purpose differential scanning calorimetry (DSC test was used. Findings: The results of DSC test showed that addition of 10vol% calcium carbonate to HDPE causes a slightly rise in its melting point but stearic acid content has no significant effect on the melting temperature of HDPE nanocomposites.Research limitations/implications: : Agglomeration of nanosized calcium carbonate during sample preparation was the major research limitation.Originality/value: Crystallization temperature of HDPE with addition of 10vol% calcium carbonate increases, while addition of stearic acid causes to decrease it. Both stearic acid content and 10vol% calcium carbonate have no significant effect on crystallinity index of HDPE.

  2. 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.

    2016-01-01

    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.

  3. Dexamethasone-loaded poly(3-hydroxybutyrate-co-3-hydroxyvalerate) microparticles for controlled release

    International Nuclear Information System (INIS)

    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 -1 and 218.54 mg.g-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. Thermoplastic starch and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) bionanocomposites before and after prolonged storage

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, N.F. [Universidade Federal do Rio de Janeiro (UFRJ), Macae, RJ (Brazil); Dahmouche, K.; Andrade, C.T. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)

    2012-07-01

    Full text: Glycerol-plasticized cornstarch and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) were melt-mixed at a constant 70:30 (wt/wt) ratio. One-step extrusion processing were performed in the presence of a commercial organically-modified clay. The effect of increasing clay contents on the morphologies and physical properties of the blends was investigated after processing, and compared to the neat blend, by scanning electron microscopy (SEM), X-ray diffraction (XRD) and dynamic mechanical analysis (DMA). The results indicated that increasing clay contents promoted improvements in the compatibility between the components and allowed to better understand the role of clay in compatibilization mechanism. After aging for 12 months, the blends were characterized by SEM, XRD and Small-Angle X-ray Scattering (SAXS). As revealed by all techniques, the reduced size of the PHBV dispersed phase and the decreased crystallinity of both phases promoted by clay particles were maintained, although some prejudicial effect of aging was noticed. Nevertheless, SAXS results unambiguously proved the presence of both exfoliated lamellae and a small number of clay tactoids in the aged bionanocomposites. (author)

  5. Soil Bacteria Population Dynamics Following Stimulation for Ureolytic Microbial-Induced CaCO3 Precipitation.

    Science.gov (United States)

    Gat, Daniella; Ronen, Zeev; Tsesarsky, Michael

    2016-01-19

    Microbial-induced CaCO3 precipitation (MICP) via urea-hydrolysis (ureolysis) is an emerging soil improvement technique for various civil engineering and environmental applications. In-situ application of MICP in soils is performed either by augmenting the site with ureolytic bacteria or by stimulating indigenous ureolytic bacteria. Both of these approaches may lead to changes in the indigenous bacterial population composition and to the accumulation of large quantities of ammonium. In this batch study, effective ureolysis was stimulated in coastal sand from a semiarid environment, with low initial ureolytic bacteria abundance. Two different carbon sources were used: yeast-extract and molasses. No ureolysis was observed in their absence. Ureolysis was achieved using both carbon sources, with a higher rate in the yeast-extract enrichment resulting from increased bacterial growth. The changes to the indigenous bacterial population following biostimulation of ureolysis were significant: Bacilli class abundancy increased from 5% in the native sand up to 99% in the yeast-extract treatment. The sand was also enriched with ammonium-chloride, where ammonia-oxidation was observed after 27 days, but was not reflected in the bacterial population composition. These results suggest that biostimulation of ureolytic bacteria can be applied even in a semiarid and nutrient-poor environment using a simple carbon source, that is, molasses. The significant changes to bacterial population composition following ureolysis stimulation could result in a decrease in trophic activity and diversity in the treated site, thus they require further attention. PMID:26689904

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Magnetic properties of layered rare-earth oxy-carbonates Ln2O2CO3 (Ln=Nd, Sm, and Dy)

    Science.gov (United States)

    Arjun, U.; Brinda, K.; Padmanabhan, M.; Nath, R.

    2016-08-01

    Polycrystalline samples of rare-earth oxy-carbonates Ln2O2CO3 (Ln=Nd, Sm, and Dy) are synthesized and their structural and magnetic properties are investigated. All of them crystallize in a hexagonal structure with space group P63 / mmc. They form a double layered structure with frustrated triangular arrangement of rare-earth magnetic ions. An antiferromagnetic transition is observed at TN ~ 1.25 K , 0.61 K, and 1.21 K for Nd2O2CO3, Sm2O2CO3, and Dy2O2CO3, respectively. From the analysis of magnetic susceptibility, the value of the Curie-Weiss temperature θCW is obtained to be ~21.7 K, 18 K, and 10.6 K for Nd2O2CO3, Sm2O2CO3, and Dy2O2CO3, respectively. The magnetic frustration parameter f(= |θCW | /TN) is calculated to be ~17.4, 31, and 8.8 for Nd2O2CO3, Sm2O2CO3, and Dy2O2CO3, respectively, which indicates that Sm2O2CO3 is strongly frustrated compared to its Nd and Dy analogues.

  11. 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.

  12. Effect of Na2Co3 on the preparation of metallic tin from cassiterite roasted under strong reductive atmosphere

    Directory of Open Access Journals (Sweden)

    Zhang Y.

    2016-01-01

    Full Text Available Tin is an indispensable metal in the modern industry. The current tin smelting processes, however, have the disadvantages of high smelting temperature, long smelting time, especially high tin loss ratio (>10 wt%. The tin loss attributes to the volatilization as gaseous SnO and stannous silicate (SnO•SiO2 residual in the slag. An innovative approach for preparing metallic tin effectively from cassiterite in the presence of Na2CO3, named gas-based reduction roasting followed by water leaching process, is under development in Central South University, China. The present study, using chemically pure SnO2 and SiO2, aims to determine the impact of Na2CO3 on the metallic tin preparation from cassiterite by the novel process using XRD, SEM-EDS, chemical analysis, etc. It was found that Na2CO3 effectively restrained the tin volatilization as SnO and the formation of hardly reductive SnO•SiO2 during the reduction roasting process. In the presence of Na2CO3, most of SnO2 in the raw materials (mixture of SnO2+SiO2 was directly reduced to metallic tin, and part of SnO2 reacted with Na2CO3 to form intermediate Na2SnO3, which was then reduced to metallic tin. The SiO2 was transformed into Na2SiO3 and then went into the water solution in the following water-leaching process. The main reactions of the SnO2 + SiO2 system in the presence of Na2CO3 under reductive atmosphere were ascertained.

  13. 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.

  14. 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.

  15. Kinetics and mechanisms of heterogeneous reaction of NO2 on CaCO3 surfaces under dry and wet conditions

    Directory of Open Access Journals (Sweden)

    Z. M. Chen

    2009-03-01

    Full Text Available Calcium nitrate (Ca(NO32 was observed in mineral dust and could change the hygroscopic and optical properties of mineral dust significantly due to its strong water solubility. The reaction of calcium carbonate (CaCO3 with nitric acid (HNO3 is believed the main reason for the observed Ca(NO32 in the mineral dust. In the atmosphere, the concentration of nitrogen dioxide (NO2 is orders of magnitude higher than that of HNO3; however, little is known about the reaction of NO2 with CaCO3. In this study, the heterogeneous reaction of NO2 on the surface of CaCO3 particles was investigated using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS combined with X-ray photoelectron spectroscopy (XPS and scanning electron microscopy (SEM under wet and dry conditions. Nitrate formation was observed in both conditions, and nitrite was observed under wet conditions, indicating the reaction of NO2 on the CaCO3 surface produced nitrate and probably nitrous acid (HONO. Relative humidity (RH influenced both the initial uptake coefficient and the reaction mechanism. With RH52%, a monolayer of water formed on the surface of the CaCO3 particles, which reacted with NO2 as a first order reaction, forming HNO3 and HONO. The initial uptake coefficient γ0 was determined to be (1.66±0.38×10−7 under dry conditions and up to (0.84±0.44×10−6 under wet conditions. Considering that NO2 concentrations in the atmosphere are orders of magnitude higher than those of HNO3, the reaction of NO2 on CaCO3 particle should have similar importance as that of HNO3 in the atmosphere and could also be an important source of HONO in the atmosphere.

  16. Hollow CoFe2O4–Co3Fe7 microspheres applied in electromagnetic absorption

    International Nuclear Information System (INIS)

    In this work, monodisperse hollow cobalt ferrite (CoFe2O4) microspheres with mean diameter of 150 nm and shell thickness of 50 nm have been successfully prepared via a one-pot solvothermal method. In order to improve the microwave absorption, a thermal reduction process was designed to synthesize hollow CoFe2O4–Co3Fe7 microspheres. Scanning electron microscopy and transmission electron microscopy images showed that the CoFe2O4–Co3Fe7 microspheres retained hollow structure. Microwave absorption results revealed that hollow CoFe2O4–Co3Fe7 microspheres exhibited much stronger electromagnetic absorption than the original hollow CoFe2O4 microspheres. Most importantly, when the sample thickness was 1.3 mm, the reflection loss (RL) less than −10 dB was obtained in the frequency range of 12.5–17.7 GHz, which nearly covered the entire Ku-band. When the sample thickness increased to 2 mm, the minimum RL was as high as −41.6 dB with the effective bandwidth (the bandwidth of RL at −10 dB) of 3 GHz. The enhanced microwave absorption was attributed to efficient complement between dielectric loss and magnetic loss. These results indicated that the hollow CoFe2O4–Co3Fe7 microspheres could be used as a new candidate for microwave absorbents, especially in Ku-band. - Highlights: • Hollow CoFe2O4–Co3Fe7 microspheres were successfully prepared through solvothermal process and subsequent thermal reduction process. • The hollow CoFe2O4–Co3Fe7 microspheres exhibit excellent microwave absorption in the entire Ku-band. • The effective bandwidth is wider than 5 GHz with a sample thickness as thin as 1.3 mm

  17. 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).

  18. 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.

  19. Transient Characterization of Carbon Monoxide, Carbon Dioxide and Oxygen Adsorbed on MgO and MgCO_3*

    OpenAIRE

    Yasuyuki, KONISHI; Toshio, KATAGIRI; Shichi, YASUI; Yoshinori, NAKANISHI; Tohru, KANNO; Masayoshi, KOBAYASHI

    1986-01-01

    The dynamic adsorption behavior of O_2, CO and CO_2 on MgO and MgCO_3 has been studied in detail at temperatures ranging from 150 to 171℃, by using the transient response method. 0n MgCO_3 no CO adsorbs and no CO oxidation proceeds. CO_2 is reversibly adsorbed obeying the Langmuir isotherm and the heat of adsorption is evaluated to be 2.7kcal/mol. On MgO, on the other hand, no CO adsorbs whereas the oxidation of CO easily proceeds and the rate equation is expressed : γ=kPco^Po_2^ The apparent...

  20. STUDI PENGGUNAAN KATALIS ABU SABUT KELAPA, ABU TANDAN SAWIT DAN K2CO3 UNTUK KONVERSI MINYAK JARAK MENJADI BIODIESEL

    OpenAIRE

    Husni Husin; Mahidin Mahidin; Marwan Marwan

    2012-01-01

    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. Trans...

  1. Preparation and Properties of Nano-CaCO_3/Short PET Fibers/PP Composites%纳米CaCO_3/PET短纤维/聚丙烯复合材料的制备及性能

    Institute of Scientific and Technical Information of China (English)

    江兴文; 殷年伟; 吉继亮; 徐洪耀

    2010-01-01

    制备了纳米CaCO_3/聚丙烯、聚对苯二甲酸乙二酯(PET)短纤维/聚丙烯、CaCO_3/PET短纤维/聚丙烯复合材料.分别测试了复合材料的力学性能,结果发现,与纳米CaO_3/聚丙烯、PET短纤维/聚丙烯两相复合材料相比,三相复合材料的力学性能尤其是冲击性能有明显的提高.采用X射线衍射(XRD)、动态力学分析(DMA)、电子扫描(SEM)系统研究了复合材料的增强机理,结果发现,在三相复合材料中,纳米CaCO_3的加入明显提高了PET短纤维与聚丙烯基体界面之间的作用力和相容性,同时纳米CaCO_3与PET短纤维的协同效应诱导了聚丙烯β晶的生成.

  2. 以CaMg(CO3)2为发泡剂制备泡沫铝的工艺探讨%Study on Preparation Process of Aluminum Foam by CaMg(CO3)2 Foaming Agent

    Institute of Scientific and Technical Information of China (English)

    陶勇

    2014-01-01

    以CaMg(CO3)2为发泡剂,Ca粉为增粘剂,ZLD 102铝硅合金为基体制备泡沫铝,探讨其工艺可行性.结果表明,以CaMg(CO3)2为发泡剂制备泡沫铝是可行的,其最佳发泡温度为710℃,搅拌时间为2 min,保温时间为4~8min.所制备泡沫铝的孔隙率可达86.42%,密度为0.36 g/cm3.%The preparation process of aluminum foam was studied using CaMg (CO3)2 as foaming agent,Ca powder as tackifier and ZLD 102 aluminium-silicon alloy as matrix.The results show that the aluminum foam can be prepared by CaMg(CO3)2 as foaming agent.The optimal foaming temperature is 710 ℃,and the optimal stirring and holding times are 2 min and 4~8 min,respectively.The porosity of the foam aluminum is 86.42%,and the density is 0.36 g/cm3

  3. 菱铁矿FeCO3高压相变与性质的第一性原理研究%Phase transition and properties of siderite FeCO3 under high pressure: an ab initio study

    Institute of Scientific and Technical Information of China (English)

    明星; 王小兰; 杜菲; 陈岗; 王春忠; 尹建武

    2012-01-01

    采用平面波赝势方法对菱铁矿FeCO3高压下的晶体结构,电子构型和电子结构进行了第一性原理计算研究.研究过程中考虑了菱铁矿FeCO3真实的反铁磁(AFM)自旋有序态,模拟静水压环境,从零压逐步加压到500 GPa.在40—50GPa压力范围内,FeCO3发生了从高自旋(HS)AFM态到低自旋(LS)非磁性(NM)态的磁性相变,伴随着晶胞体积坍塌10.5%.FeCO3在相变前后均是绝缘体,但是相变后的LS-NM态的Fe~(2+)离子的3d电子局域化程度更强,能隙随着压力的进一步增大而逐步增大,离化程度更高,直到500 GPa没有发生金属绝缘体相变.%The crystal structure, electronic configuration and electronic structure of siderite FeCO3 are studied by first-principles calculations through the plane wave pseudo-potential method. The real antiferromagnetic (AFM) spin ordering state is considered. The pressure increases up to 500 GPa under hydrostatic pressure condition. FeCO3 transforms from high spin (HS) AFM state to low spin (LS) nonmagnetic (NM) state in a pressure range between 40 and 50 GPa, accompaned with a volume collapse of 10.5%. Siderite FeCO3 is insulating before and after the phase transition, but the 3d electrons of Fe^2+ ions for the LS-NM state are more localized, The band gap increases with pressure increasing, and the LS-NM state moves into a more strong ionic state and no metal-insulator transition (MIT) occurs.

  4. 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.

  5. Tailoring of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) copolymers for bone tissue applications

    Science.gov (United States)

    Liu, Hui

    Considerable scientific and technological progress has been made in formulating biomaterials based on natural and synthetic polymers for ultimate use in bone tissue scaffolding. One class of polymers that has drawn attention in recent years for bone tissue engineering application is the biodegradable polymer poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). PHBV, a microbial polymer, has gained special importance because of favorable mechanical characteristics, biological properties, highly adaptable structure, non-toxic degradation products, and minimal inflammatory response when used as scaffold. However, the lack of natural cell recognition sites on PHBV has resulted in delayed cell attachment, proliferation, differentiation, and tissue regeneration on the polymer. The primary objective of this research is to modify PHBV so as to improve the biocompatibility of the matrix. An approach was developed to prepare porous and bioactive molecule coated scaffold so as to improve the biocompatibility of PHBV matrix. We investigated the role of porosity, collagen coating, and ozone treatment of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) scaffold on cell proliferation. Based on biochemical assay, we established that maximum cell proliferation occurs on collagen coated and ozone treated porous PHBV film followed by collagen coated porous PHBV film than on porous PHBV film and the least on nonporous PHBV film. Confocal microscopy in combination with biochemical assay was used to generate 3D map of viable cell proliferation on the bulk PHBV matrix. The cells were cultivated on modified PHBV film in mineralization media containing beta-glycerol phosphate for predetermined time interval and later calcium deposits were stained with alizarin red-S assay. Atomic absorption (AA) technique was used to measure the Ca2+ content of the medium and it was found that the longer the cells were incubated in organic phosphate medium, the greater amount of Ca2+ from the medium

  6. 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%.

  7. 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.

  8. 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.

  9. 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.

  10. Study on Morphology and Properties of PP/CaCO3/PP-g-AA Composites%PP/CaCO3/PP—g—AA复合材料形态与性能研究

    Institute of Scientific and Technical Information of China (English)

    朱清梅; 李淑华; 赵研峰; 付博

    2012-01-01

    Acrylic acid grafted polypropylene(PP-g-AA) was prepared via melt grafting using a two screw extruder equipped with a liquid feeding, which was used as a compstibilizer in PP/CaCO3 system. The resulted system was studied using Fourier transform infrared spectroscopy(FTIR), differential scanning calorimetery(DSC), and scanning electron microscope(SEM). When content of CaCO3 was 10 % and content of PP-g-AA(grafting ratio 2. 204%) was 10 %, a set of optimal mechanical properties was obtained.%采用双螺杆挤出机液体进料熔融接枝制备了丙烯酸接枝聚丙烯(PP-g-AA),研究了聚丙烯(PP)/碳酸钙(CaCO3)/PP-g-AA复合材料的力学性能,并采用红外光谱、差示扫描量热仪、扫描电子显微镜等对复合材料进行了表征分析。结果表明,用此PP-g-AA作为PP/CaCO3的相容剂时,能有效提高其力学性能,且当CaCO3的含量为10%(质量分数,下同),接枝率为2.204%的PP-g-AA的含量为10%时,效果最佳。

  11. Synthesis of Co3O4 nanoparticles with block and sphere morphology, and investigation into the influence of morphology on biological toxicity

    Science.gov (United States)

    RAMAN, VENKATARAMANAN; SURESH, SHRUTHI; SAVARIMUTHU, PHILIP ANTHONY; RAMAN, THIAGARAJAN; TSATSAKIS, ARISTIDES MICHAEL; GOLOKHVAST, KIRIL SERGEEVICH; VADIVEL, VINOD KUMAR

    2016-01-01

    In the present study, cobalt oxide (Co3O4) magnetic nanoparticles with block and sphere morphologies were synthesized using various surfactants, and the toxicity of the particles was analyzed by monitoring biomarkers of nanoparticle toxicity in zebrafish. The use of tartarate as a surfactant produced highly crystalline blocks of Co3O4 nanoparticles with pores on the sides, whereas citrate lead to the formation of nanoparticles with a spherical morphology. Co3O4 structure, crystallinity, size and morphology were studied using X-ray diffractogram and field emission scanning electron microscopy. Following an increase in nanoparticle concentration from 1 to 200 ppm, there was a corresponding increase in nitric oxide (NO) generation, induced by both types of nanoparticles [Co3O4-NP-B (block), r=0.953; Co3O4-NP-S (sphere), r=1.140]. Comparative analyses indicated that both types of nanoparticle produced significant stimulation at ≥5 ppm (P<0.05) compared with a control. Upon analyzing the effect of nanoparticle morphology on NO generation, it was observed that Co3O4-NP-S was more effective compared with Co3O4-NP-B (5 and 100 ppm, P<0.05; 200 ppm, P<0.01). Exposure to both types of nanoparticles produced reduction in liver glutathione (GSH) activity with corresponding increase in dose (Co3O4-NP-B, r=−0.359; Co3O4-NP-S, r=−0.429). However, subsequent analyses indicated that Co3O4-NP-B was more potent in inhibiting liver GSH activity compared with Co3O4-NP-S. Co3O4-NP-B proved to be toxic at 5 ppm (P<0.05) and GSH activity was almost completely inhibited at 200 ppm. A similar toxicity was observed with both types of Co3O4-NPs against brain levels of acetylcholinesterase (AChE; Co3O4-NP-B, r=−0.180; Co3O4-NP-S, r=−0.230), indicating the ability of synthesized Co3O4-NPs to cross the blood-brain barrier and produce neuronal toxicity. Co3O4-NP-B showed increased inhibition of brain AChE activity compared with Co3O4-NP-S (1,5, and 10 ppm, P<0.05; 50, 100 and 200 ppm, P

  12. 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

    -ray 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...

  13. 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

  14. Biosynthesis, Characterization, and Hemostasis Potential of Tailor-Made Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Produced by Haloferax mediterranei

    DEFF Research Database (Denmark)

    Han, Jing; Wu, Linping; Hou, Jing;

    2015-01-01

    We report the biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) random copolymers (R-PHBV) or higher-order copolymers (O-PHBV) in Haloferax mediterranei, with adjustable 3-hydroxyvalerate (3HV) incorporation by cofeeding valerate with glucose. Their microchemical structure, molecular w...

  15. 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.

  16. 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.

  17. Electro-catalytic degradation of bisphenol A with modified Co3O4/β-PbO2/Ti electrode

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Co3O4/β-PbO2 electrode was prepared and an excellent electrocatalytic property. • Co3O4/β-PbO2 electrode had good corrosion resistance characterization and lifetime. • BPA electrocatalytic degradation followed pseudo-first-order reaction process. - Abstract: Ti-base Co3O4/β-PbO2 composite electrodes were prepared using electro-deposition and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), cyclic voltammetry and the accelerated life testing, it indicated that the self-made electrode had high activity in electrolysis as well as excellent corrosion resistance and excellent catalytic performance. The results showed that the removal efficiency of CODCr could be reached up to 92.2% after 1.5 h electrolysis at NaCl concentration of 0.020 mol·L−1, bisphenol A initial concentration of 20 mg·L−1, applied voltage of 20 V, electrode spacing of 7 cm and electrolyte pH of 5. The reaction mechanism and kinetics of Co3O4/β-PbO2/Ti composite electrodes electro-catalytic degradation bisphenol A mainly caused by the OH radical attacking parent molecules and the degradation followed pseudo-first-order kinetics

  18. Hierarchically porous Co3O4 architectures with honeycomb-like structures for efficient oxygen generation from electrochemical water splitting

    Science.gov (United States)

    Li, Lili; Tian, Tian; Jiang, Jing; Ai, Lunhong

    2015-10-01

    The development of efficient and cheap anode materials for the utilization in the oxygen evolution reaction (OER) is essential for energy-conversion technologies. In this study, hierarchically porous Co3O4 architectures with honeycomb-like structures are synthesized by employing cobalt-based zeolitic imidazolate framework (ZIF-67-Co) as metal source and sacrificial template. After a simple one-step calcination process, the ZIF-67-Co precursor can be chemically transformed into the Co3O4 architectures with abundant porosity and oxygen vacancy. These easily obtained and earth-abundant Co3O4 architectures present high performance toward the electrochemical water splitting for evolving molecular oxygen, affording a small OER onset potential, large anodic current and long-term durability in 0.1 M KOH solution, which are comparable to the electroactive noble- and transition-metal oxygen evolution catalysts previously reported. These merits suggest that the ZIF-derived Co3O4 architectures are promising electrocatalysts for OER from water splitting.

  19. Treatment of trichloroethene and hexavalent chromium by granular iron in the presence of dissolved CaCO3

    Science.gov (United States)

    Jeen, Sung-Wook; Yang, YanQi; Gui, Lai; Gillham, Robert W.

    2013-01-01

    Column experiments and numerical simulations were conducted to evaluate the effects of Cr(VI) and dissolved CaCO3 on the iron reactivity towards trichloroethene (TCE) and Cr(VI) reduction. Column experiments included measurements of iron corrosion potential and characterization of surface film composition using Raman spectroscopy. Three columns received different combinations of TCE (5 mg L- 1), Cr(VI) (10 mg L- 1) and dissolved CaCO3 (300 mg L- 1), after short periods of conditioning with Millipore water followed by 10 mg L- 1 TCE in Millipore water, for a total of 8 months. The results showed that co-existence with TCE did not affect Cr(VI) reduction kinetics, however, the presence of Cr(VI) reduced TCE degradation rates significantly. The formation of Fe(III)/Cr(III) products caused progressive passivation of the iron and was consistent with the increase in corrosion potential. The presence of dissolved CaCO3 resulted in a stable corrosion potential and faster degradation rates of TCE and Cr(VI). Over time, however, the accumulation of secondary carbonate minerals on the iron surface decreased the iron reactivity. Numerical simulation using a reactive transport model reproduced the observations from the column experiments reasonably well. The simulation can be valuable in the design of PRBs or in the development of effective maintenance procedures for PRBs treating groundwater co-contaminated with Cr(VI) and TCE in the presence of dissolved CaCO3.

  20. 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.

  1. Fabrication of AgX-loaded Ag2CO3 (X = Cl, I) composites and their efficient visible-light-driven photocatalytic activity

    International Nuclear Information System (INIS)

    Highlights: • The novel AgX/Ag2CO3 composites have been synthesized by ion exchange reaction. • AgX/Ag2CO3 exhibit higher photoactivity and stability than that of Ag2CO3. • The band structure of AgX/Ag2CO3 is beneficial to improve the photoactivity. - Abstract: The novel visible-light-driven AgX/Ag2CO3 (X = Cl, I) hybrid materials were synthesized by ion exchange reaction. The physical and chemical properties of the catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), diffuse-reflection spectra (DRS) and photocurrent techniques. The as-prepared AgX/Ag2CO3 (X = Cl, I) composites showed higher photocatalytic activity than that of the pure Ag2CO3 photocatalyst under visible light irradiation (λ ⩾ 400 nm) in the process of methylene blue (MB) degradation. The optimal mass percentage of AgCl and AgI in the AgX/Ag2CO3 (X = Cl, I) composite was 20.54 wt% and 40 wt%, respectively. The enhancement of photocatalytic activity was attributed to the suitable band potential between AgX and Ag2CO3, which was beneficial to increase the separation efficiency of electrons and holes. Besides, the photocatalytic mechanism of AgX/Ag2CO3 (X = Cl, I) composites was also proposed

  2. 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.

  3. An amperometric hydrogen peroxide biosensor based on Co3O4 nanoparticles and multiwalled carbon nanotube modified glassy carbon electrode

    International Nuclear Information System (INIS)

    Highlights: • Hydrogen peroxide biosensor was constructed by combining the advantageous properties of MWCNTs and Co3O4. • Incorporating Co3O4 nanoparticles into MWCNTs/gelatin film increased the electron transfer. • Co3O4/MWCNTs/gelatin/HRP/Nafion/GCE showed strong anti-interference ability. • Hydrogen peroxide was successfully determined in disinfector with an average recovery of 100.78 ± 0.89. - Abstract: In this work a new type of hydrogen peroxide biosensor was fabricated based on the immobilization of horseradish peroxidase (HRP) by cross-linking on a glassy carbon electrode (GCE) modified with Co3O4 nanoparticles, multiwall carbon nanotubes (MWCNTs) and gelatin. The introduction of MWCNTs and Co3O4 nanoparticles not only enhanced the surface area of the modified electrode for enzyme immobilization but also facilitated the electron transfer rate, resulting in a high sensitivity of the biosensor. The fabrication process of the sensing surface was characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Amperometric detection of hydrogen peroxide was investigated by holding the modified electrode at −0.30 V (vs. Ag/AgCl). The biosensor showed optimum response within 5 s at pH 7.0. The optimized biosensor showed linear response range of 7.4 × 10−7–1.9 × 10−5 M with a detection limit of 7.4 × 10−7. The applicability of the purposed biosensor was tested by detecting hydrogen peroxide in disinfector samples. The average recovery was calculated as 100.78 ± 0.89

  4. 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; Jishua

    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.

  5. Theoretical study on mechanism of the photochemical ligand substitution of fac-[Re(I)(bpy)(CO)3(PR3)](+) complex.

    Science.gov (United States)

    Saita, Kenichiro; Harabuchi, Yu; Taketsugu, Tetsuya; Ishitani, Osamu; Maeda, Satoshi

    2016-07-14

    The mechanism of the CO ligand dissociation of fac-[Re(I)(bpy)(CO)3P(OMe)3](+) has theoretically been investigated, as the dominant process of the photochemical ligand substitution (PLS) reactions of fac-[Re(I)(bpy)(CO)3PR3](+), by using the (TD-)DFT method. The PLS reactivity can be determined by the topology of the T1 potential energy surface because the photoexcited complex is able to decay into the T1 state by internal conversions (through conical intersections) and intersystem crossings (via crossing seams) with sufficiently low energy barriers. The T1 state has a character of the metal-to-ligand charge-transfer ((3)MLCT) around the Franck-Condon region, and it changes to the metal-centered ((3)MC) state as the Re-CO bond is elongated and bent. The equatorial CO ligand has a much higher energy barrier to leave than that of the axial CO, so that the axial CO ligand selectively dissociates in the PLS reaction. The single-component artificial force induced reaction (SC-AFIR) search reveals the CO dissociation pathway in photostable fac-[Re(I)(bpy)(CO)3Cl]; however, the dissociation barrier on the T1 state is substantially higher than that in fac-[Re(I)(bpy)(CO)3PR3](+) and the minimum-energy seams of crossings (MESXs) are located before and below the barrier. The MESXs have also been searched in fac-[Re(I)(bpy)(CO)3PR3](+) and no MESXs were found before and below the barrier. PMID:27306043

  6. 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

  7. Synthesis of nano-bound microsphere Co3O4 by simple polymer-assisted sol–gel technique

    International Nuclear Information System (INIS)

    Nano-bound Co3O4 microspheres and molten Co3O4 microspheres were synthesized for the first time by a simple polymer (poly-(vinylpyrrolidone))-assisted sol–gel and sol–gel technique, respectively. Thermal decomposition of the precursor samples of both polymer-assisted sol–gel and sol–gel technique were studied by thermogravimetric analysis. In both techniques, the material was calcined at different temperatures for the formation of phase pure Co3O4. X-ray diffraction confirmed the formation of phase pure cubic spinel structured Co3O4 at 400 and 500 °C for the polymer-assisted sol–gel and sol–gel technique, respectively. Fourier transform infrared spectroscopy revealed the vibrational assignments of functional groups associated with the cubic spinel structure of Co3O4. Scanning electron microscopy of all samples showed clear microsphere sizes ranging from 1 to 4 μm. Both techniques allowed the formation of spherical-shaped microspheres by a simple process. Nano-bound microspheres were observed from the polymer-assisted sol–gel technique because the decomposition of PVP at 400 °C is the main reason for the formation of nano-bound microspheres. The nanoparticle size of the nano-bound microsphere measured by transmission electron microscopy was ∼40 nm. Therefore, PVP is an essential compound for the formation of nano-bound microspheres. This very simple and inexpensive technique is suitable for the formation of spherical-shaped microspheres.

  8. 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%.

  9. Influence of Nano-CaCO3 on Ultra High Performance Concrete%纳米CaCO3对超高性能混凝土性能影响的研究

    Institute of Scientific and Technical Information of China (English)

    黄政宇; 祖天钰

    2013-01-01

    利用水化放热分析、差热分析、收缩仪、扫描电镜、流动扩展度、力学试验等手段研究了纳米CaCO3对超高性能混凝土体系的水化放热特点、结合水含量、收缩、水化产物特征、流动性、力学性能的影响;分析了胶凝材料体系水化硬化后的微观结构及其对宏观性能的影响规律.结果表明:超低水胶比的超高性能混凝土的水化放热速率低,但掺入纳米CaCO3能促进水化反应,提高水化开始时的放热速率.同时,掺入纳米CaCO3会使得超高性能混凝土的流动性下降,自收缩增加,但能提高超高性能混凝土的抗压强度及抗折强度,改善水泥浆体的微观结构,使得超高性能混凝土的结构更加均匀、密实.%The hydration process such as bound water content,exothermic rate and autogenous shrinkage,characteristics of hydration products,spread value and mechanic performance of ultra high performance concrete (UHPC) which containing nano-CaCO3 particles were investigated using calorimetry,thermogravitymetric analysis,non-contact concrete shrinkage deformation tester,SEM,fluidity,mechanic tests.Microstructure of hardened cementitious system and its influence on macro performance were analyzed.The results indicate that the exothemic rate of UHPC is very low while it can increase the exothermic rate when adding nano-CaCO3 into the system.It will also decrease spread value,increase the amount of autogenous shrinkage,improve the flextural strength and compressive strength,and optimize the microstructures when containg nano-CaCO3 particles.

  10. 99mTc(CO)3 - nitrofuryl thiosemicarbazone a novel infection imaging agent

    International Nuclear Information System (INIS)

    Full text: To develop a potential Technetium labeled infection imaging agent 5-NTS prepared and labeled and its scintigraphic imaging done in rat model. Objective: Diagnosis of deep seated infection is a very challenging problem. Differentiation between bacterial infection and sterile inflammation is also difficult. As thiosemicarbazone compound show antibacterial activity, so a new infection imaging agent was prepared. Their in-vitro and in-vitro stability studies, through biological screening and scintigraphic imaging of the chelates labeled with 99mTc studied on infected thigh muscle tissues in rat model. Materials and Methods: Synthesis of 5-nitrofural thiosemicarbazone An equimolar mixture of 5 nitrofural and thiosemicarbazide was stirred with p-TsOH (catalytic amounts) in dry toluene. Synthesized compound characterized by 1H-NMR and ESI-MS. The synthesized compound labeled with 99mTc(CO)3 precursor and 99mTc-oxo(V) core using stannous chloride reduction method. Labeled compound was characterized by TLC in acetone, brine, and ethanol: water: acetic acid: pyridine (1:5:5:1) and also with reverse phase C-18 column. In-vitro stability study was tested in challenge assay with increasing concentration of DTPA (0, 102, 103, 104, 105 molar excess) for 4 hour. Serum stability was also done and its stability analyzed at 0, 2, 8, 18, 24 hour. Infection was induced in rats (Sprague Dawley, 200-220gm) by injecting 0.2 ml of freshly prepared harvested culture of S. aureus (2x108cfu) in left thigh muscle. One day after when the infection was apparent, radiopharmaceutical (185-259 kBq/0.1ml) was injected intravenously. For comparison sterile inflammation was induced by an intramuscular injection of 0.1ml of Terpentine oil I. P. to left thigh muscle. The infected animal with radiopharmaceuticals sacrificed at 1, 4, 8, 24 hour post injection, desired organ were collected and transferred to counting vials. Blood samples were obtained by puncture of the heart. Results: Expressed

  11. 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

  12. Siliceous mesostructured cellular foams/ poly(3-hydroxybutyrate-co-3-hydroxyhexanoate composite biomaterials for bone regeneration

    Directory of Open Access Journals (Sweden)

    Yang S

    2014-10-01

    Full Text Available Shengbing Yang,1,* Shuogui Xu,2,* Panyu Zhou,2,* Jing Wang,3 Honglue Tan,4 Yang Liu,5 TingTing Tang,4 ChangSheng Liu1,3,5 1The State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People’s Republic of China; 2Changhai Hospital, Department of Orthopedics, the Second Military Medical University, Shanghai, People’s Republic of China; 3Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai, People’s Republic of China; 4Shanghai Key Laboratory of Orthopedic Implant, Department of Orthopedic Surgery, Shanghai 9th People’s Hospital, Shanghai Jiao Tong University School of Medicine China, Shanghai, People’s Republic of China; 5Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai, People’s Republic of China *These authors contributed equally to this workAbstract: Osteoinductive and biodegradable composite biomaterials for bone regeneration were prepared by combining poly(3-hydroxybutyrate-co-3-hydroxyhexanoate (PHBHHx with siliceous mesostructured cellular foams (SMC, using the porogen leaching method. Surface hydrophilicity, morphology, and recombinant human bone morphogenetic protein 2 adsorption/release behavior of the SMC/PHBHHx scaffolds were analyzed. Results of scanning electron microscopy indicated that the SMC was uniformly dispersed in the PHBHHx scaffolds, and SMC modification scaffolds have an interconnected porous architecture with pore sizes ranging from 200 to 400 µm. The measurements of the water contact angles suggested that the incorporation of SMC into PHBHHx improves the hydrophilicity of the composite. In vitro studies with simulated body fluid show great improvements to bioactivity and biodegradability versus pure PHBHHx scaffolds. Cell adhesion and cell proliferation on the scaffolds was also evaluated, and the new

  13. Reduced Graphene-Wrapped MnO2 Nanowires Self-Inserted with Co3 O4 Nanocages: Remarkable Enhanced Performances for Lithium-Ion Anode Applications.

    Science.gov (United States)

    Zhu, Qi; Li, Yunhui; Gao, Ying; Wang, Xiao; Song, Shuyan

    2016-05-10

    A simple synthetic approach for graphene-templated nanostructured MnO2 nanowires self-inserted with Co3 O4 nanocages is proposed in this work. The Co3 O4 nanocages were penetrated in situ by MnO2 nanowires. As an anode, the as-obtained MnO2 -Co3 O4 -RGO composite exhibits remarkable enhanced performance compared with the MnO2 -RGO and Co3 O4 -RGO samples. The MnO2 -Co3 O4 -RGO electrode delivers a reversible capacity of up to 577.4 mA h g(-1) after 400 cycles at 500 mA g(-1) and the Coulombic efficiency of MnO2 -Co3 O4 -RGO is about 96 %. PMID:27071726

  14. 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

  15. 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.

  16. Evolution of Slow Magnetic Relaxation: from Diamagnetic Matrix Y(OH)CO3 to Dy(0.06)Y(0.94)(OH)CO3 with High Spin-Reversal Barrier and Blocking Temperature.

    Science.gov (United States)

    Liu, Jiang; Chen, Yan-Cong; Lai, Jia-Jun; Wu, Zi-Hao; Wang, Long-Fei; Li, Quan-Wen; Huang, Guo-Zhang; Jia, Jian-Hua; Tong, Ming-Liang

    2016-03-21

    A stable Dy(III)-dispersed compound with single-molecule magnet behavior, Dy(0.06)Y(0.94)(OH)CO3, was isolated by a general strategy targeted at the doping of paramagnetic Dy(3+) into a diamagnetic 3D inorganic network of Y(OH)CO3. The single-ion origin of slow magnetic relaxation was gradually released as variations of the dysprosium/yttrium ratio and finally gave a relatively large spin-reversal barrier around 200 K and high hysteresis temperature of 8 K. This study opens up new opportunities to investigate the slow magnetic relaxation and magnetostructural correlation by choosing a suitable inorganic architecture with strong axial anisotropy. PMID:26959174

  17. 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

  18. 纳米CaCO3表面改性方法综述%Review on the methods of surface modification of nanometer calcium carbonate

    Institute of Scientific and Technical Information of China (English)

    王训遒; 蒋登高

    2007-01-01

    简述了纳米CaCO3表面改性的原因,综述了国内外纳米CaCO3表面改性的方法,着重介绍了表面活性剂、偶联剂、无机改性剂和复合改性剂等在纳米CaCO3表面改性方面的应用,并对我国纳米CaCO3产业的发展提出了建议.

  19. 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.

  20. Atomic layer deposition of Co3O4 on carbon nanotubes/carbon cloth for high-capacitance and ultrastable supercapacitor electrode

    International Nuclear Information System (INIS)

    Co3O4 nanolayers have been successfully deposited on a flexible carbon nanotubes/carbon cloth (CC) substrate by atomic layer deposition. Much improved capacitance and ultra-long cycling life are achieved when the CNTs@Co3O4/CC is tested as a supercapacitor electrode. The improvement can be from the mechanically robust CC/CNTs substrate, the uniform coated high capacitance materials of Co3O4 nanoparticles, and the unique hierarchical structure. The flexible electrode of CNTs@Co3O4/CC with high areal capacitance and excellent cycling ability promises great potential for developing high-performance flexible supercapacitors. (paper)

  1. Co3O4 NPs Embedded in N-doped Carbon Fibers as a Bifunctional Electrocatalyst for Oxygen Reduction and Evolution Reactions

    Science.gov (United States)

    Guo, Yao-Fang; Liu, Ting; Sun, Ke-Ning

    2016-05-01

    Oxygen reduction and evolution reactions are important and major challenges to Li-air batteries. In this report, a three-dimensional (3D) bifunctional electrocatalyst was prepared by embedding Co3O4 nanoparticles into nitrogen-doped carbon nanofibers (denoted as Co3O4-NCNF) by a facile method. The Co3O4-NCNF possesses a high specific surface area(403.5 m2/g) and porous structure. The Co3O4-NCNF exhibits an excellent catalytic activity and long-time durability for both oxygen reduction and evolution reactions in alkaline solutions.

  2. Preparation of β-polypropylene/nano-CaCO3/PET short fiber composites%β晶型PP/纳米CaCO3/短切PET纤维复合材料的制备

    Institute of Scientific and Technical Information of China (English)

    林志丹; 陈超; 管子现; 徐宝峰; 黄卓瑶

    2013-01-01

    β-polypropylene (PP)/nano-CaCO3/polyethylene glycol terephthalate (PET) fiber composites were prepared by means of melt extrusion blending, and the compatibility of the composites was improved by maleic anhydride (MAH) grafted PP (PP-g-MAH). The effects of PET filer, the P-nucleating agent and compatilizer on the mechanical properties, compatibility, and crystallization and melting behavior of the composites were studied. The results indicate that CaCO3 and PET fiber play heterogeneous nucleating role for crystallization of PP and can synergistically induce the formation of β-PP. Adding PET fiber can enhance the composites' rigidity and toughness but damage their tensile property. PP-g-MAH improves the compatibility of PP and PET fiber and facilitates the dispersion of the p-nucleating agent in the composites, resulting in the formation of more β-crystal.%通过熔融挤出共混制备β晶型聚丙烯(PP)/纳米CaCO3/对苯二甲酸乙二酯(PET)纤维复合材料,并用马来酸酐(MAH)接枝PP(PP-g-MAH)改善材料的相容性.研究了PET纤维、β成核剂和相容剂对材料力学性能、相容性和结晶熔融行为的影响.结果表明:CaCO3和PET纤维对PP的结晶具有异相成核作用,能协同诱导形成β晶型PP.加入PET纤维可提高材料的刚性和韧性,但会损坏拉伸性能.PP-g-MAH能改善PP和PET纤维之间的相容性,并能促进成核剂在材料中的分散,形成更多的β晶.

  3. Synthetic swartzite, CaMg[UO2(CO3)3].12H2O, and its strontium analogue, SrMg[UO2(CO3)3].12H2O: Crystallography and crystal structure

    International Nuclear Information System (INIS)

    The crystal structures of synthetic swartzite, CaMg[UO2(CO3)3].12H2O, monoclinic, space group P21/m, a=11.080(2), b=14.634(2), c=6.439(1)A, β=99.43(1)0, Z=2, and of its strontium analogue, SrMg[UO2(CO3)3].12H2O, a=11.216(2), b=14.739(2), c=6.484(1)A, β=99.48(1)0, have been determined from X-ray four-circle diffractometer data and refined to R=0.023 for 2790 and R=0.026 for 1626 reflections, respectively. Most interesting feature of the two structures are isolated dinuclear groups (M(H2O)6[UO2(CO3)3])2-, where M=Ca or Sr form M(H2O)6O2 square antiprisms which are edge-linked with UO2O6 hexagonal bipyramids. Isolated Mg(H2O)62+ octahedra and a system of hydrogen bonds complete the structures. Morphological and optical data of both compounds are given. (orig.)

  4. 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.

  5. 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.

  6. Egg albumin-assisted preparation, characterization and influencing factors of Dumbbell-shaped BaCO3 superstructures

    International Nuclear Information System (INIS)

    Dumbbell-shaped barium carbonate superstructures were successfully synthesized in the aqueous system containing egg albumin and ethylenediaminetetraacetate disodium (EDTA-2Na), employing BaCl2, NaHCO3 and NH3.H2O as the starting reagents. The as-prepared product was characterized by X-ray powder diffraction (XRD), energy dispersive spectrometry (EDS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Some factors influencing the morphology of BaCO3 crystals, such as the time, the amounts of egg albumin and EDTA-2Na, were studied. Experimental facts showed that a proper amount of egg albumin and EDTA-2Na played crucial roles in the formation of dumbbell-shaped BaCO3 superstructures.

  7. 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.

  8. Fabrication, structure and magnetic properties of CoPt3, CoPt and Co3Pt nanoparticles

    International Nuclear Information System (INIS)

    A set of CoxPt100-x nanoparticles (NPs) was synthesized by the sol-gel method. The structure and magnetic properties of the produced samples were investigated by x-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and a vibrating sample magnetometer. When the Co content ranged from 25 to 75 at%, the results of XRD, HRTEM and SAED revealed the formation of L12 CoPt3, L10 CoPt and face-centred cubic Co3Pt NPs. Magnetic measurements indicated that CoPt3 and Co3Pt had soft magnetic properties. When the Co composition was 50 at%, the sample coercivity reached a giant value of ∼470 kA m-1.

  9. Formation of hydrogen in oxidative coupling of methane over BaCO3 and MgO catalysts

    Institute of Scientific and Technical Information of China (English)

    Zhiming Gao; Jiansheng Zhang; Ruiyan Wang

    2008-01-01

    Hydrogen formed in oxidative coupling of methane(OCM) over BaCO3 and MgO catalysts was measured since the data of H2 selectivity were missing almost in all articles published heretofore.It was found that H2 selectivity achieved about 18%.when C2 hydrocarbon's selectivity was maintained at 48%-45%over BaCO3 catalyst at the feed molar ratio of CH4/O2=4 in temperature range of 780℃-820℃.Under similar conditions,H2 selectivity was about 14%-16%over MgO catalyst.with C2 selectivity maintained at 41%-42%.Possible routes for hydrogen formation in OCM reaction were discussed.Effect of addition of alkali metallic ions was also investigated.

  10. Pure and Ni-substituted Co3O4 spinel catalysts for direct N2O decomposition

    Institute of Scientific and Technical Information of China (English)

    Bahaa M. Abu-Zied; Soliman A. Soliman; Sarah E. Abdellah

    2014-01-01

    A series of NixCo1-xCo2O4 (0 ≤ x ≤ 1) spinel catalysts were prepared by the co-precipitation method and used for direct N2O decomposition. The decomposition pathway of the parent precipitates was characterized by thermal analysis. The catalysts were calcined at 500 °C for 3 h and characterized by powder X-ray diffraction, Fourier transform infrared, and N2 adsorption-desorption. Nickel co-baltite spinel was formed in the solid state reaction between NiO and Co3O4. The N2O decomposition measurement revealed significant increase in the activity of Co3O4 spinel oxide catalyst with the partial replacement of Co2+ by Ni2+. The activity of this series of catalysts was controlled by the de-gree of Co2+ substitution by Ni2+, spinel crystallite size, catalyst surface area, presence of residual K+, and calcination temperature.

  11. CO3O4纳米颗粒的制备及其电化学性能%Synthesis and the Electrochemical Performances of Co3O4 Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    金小青; 杨彬; 冯晓娟

    2013-01-01

    The Co( Ⅱ )1-x Co ( Ⅲ )x ( OH ) 2-y ( NO3)x+y precursor was synthesized by a chemical co-precipitation method. The Co3 O4 nanoparticles were obtained when the precursor was calcined. The components, structure and morphology of products were analyzed by FT-IR and X-ray diffraction ( XRD) and field emission scanning electron microscopy ( FE-SEM ) , respectively. The electrochemical performances of the as-prepared nanoparticles were investigated by cyclic voltammetry and constant current charge/discharge techniques. The results showed that Co3O4-300 has excellent electrochemical performances, and its specific capacitance as single electrode is up to 338F/g and remains at about 93% of the initial value after 1000 cycles at current density of 1 A/g. It is a promising electrode material for supercapacitor.%采用化学共沉淀方法制备前驱体Co(Ⅱ)1-xCo(Ⅲ)x(OH)2-y(NO3)x+y,经焙烧后得Co3O4纳米颗粒.用红外光谱对所制样品的成分进行分析;用X射线衍射和场发射扫描电子显微镜表征产物的结构和形貌;用循环伏安、恒电流充放电等测试方法对Co3O4电化学性能进行研究.测试表明,Co3O4-300具有最佳的电容性能,单电极比电容可达338F/g,并且在1A/g电流密度下循环1000周后,比电容仍能保持93%,有望成为电化学电容器的电极材料.

  12. 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.

  13. The role of oxygen during the catalytic oxidation of ammonia on Co3O4(1 0 0)

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Ammonia oxidation on Co3O4(1 0 0) surface is studied using Density Functional Theory. • The role of lattice O, on-surface O and OH in the dehydrogenation of ammonia is clarified. • NO and H2O are the main products of ammonia oxidation on Co3O4(1 0 0). • The Co3O4 surface is itself capable of oxidising NH3 to NO using the lattice O, opening the way for a Mars–van Krevelen mechanism of reaction. - Abstract: The adsorption selectivity and dehydrogenation energy barriers of NH3, NH2 and NH on the (1 0 0) surface planes of Co3O4 are determined by means of density functional methods. Stepwise hydrogen abstraction is effected by lattice O3o associated with octahedrally coordinated surface Co atoms. The final H-abstraction, from NH, leads directly to the formation of gaseous product NO with the creation of a lattice oxygen vacancy. Reaction of this vacancy with gas-phase O2 repairs the vacancy and creates surface-adsorbed O* which is also capable of abstracting H from NH3*, NH2* and NH*, the final step leading to directly again to NO formation. The mobile surface OH* formed from the O*-mediated abstraction steps is also capable of abstracting H from the NHx* species, leading ultimately to surface N* which then easily extracts a lattice O3o to form NO and a new vacancy. The overall mechanism to form NO is a complex cycle of lattice- and surface-mediated abstractions. The hydrogen budget in the reaction shows corresponding complexity. Surface H* (formed when lattice O3o abstracts H from NHx) is stable and immobile but it can be abstracted by surface OH* to form water. OH* disproportionation reaction also forms water

  14. 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

    2016-05-01

    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. PMID:27052835

  15. 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.

  16. 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 < 1.0) for high-Mg calcite and aragonite mineral phases at acidification levels before the end of this century. Week-long periods of undersaturation occur for 18 mol% high-Mg calcite after storms by the end of the century. In a high-CO2 world, CaCO3 undersaturation of coral reef seawater can occur as a result of even modest tropical cyclones. The expected increase in the 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.

  17. Physiologic and metagenomic attributes of the rhodoliths forming the largest CaCO3 bed in the South Atlantic Ocean

    OpenAIRE

    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.

    2013-01-01

    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 me...

  18. Effect of ultrafine talc on crystallization and end-use properties of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)

    OpenAIRE

    VANDEWIJNGAARDEN, Jens; Murariu, Marius; Dubois, Philippe; Carleer, Robert; Yperman, Jan; D'Haen, Jan; Peeters, Roos; Buntinx, Mieke

    2016-01-01

    Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) is a highly versatile polyhydroxyalkanoate. To enhance its slow crystallization, the performance of ultra-fine talc (median diameter of 1 mm) as a nucleating agent is studied. This study focuses on crystallization, but also on the effect on fundamental properties (i.e., thermal stability) and selected end-use properties (i.e., color, opacity, tensile properties, and gas permeability), to assess its applicability for food packaging purpose...

  19. Effect of ultrafine talc on crystallization and end-use properties of poly(3-hydrocybutayrate-co-3-hydroxyhexanoate)

    OpenAIRE

    VANDEWIJNGAARDEN, Jens; Murariu, Marius; Dubois, Philippe; Carleer, Robert; Yperman, Jan; D'Haen, Jan; Peeters, Roos; Buntinx, Mieke

    2016-01-01

    Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) is a highly versatile polyhydroxyalkanoate. To enhance its slow crystallization, the performance of ultra-fine talc (median diameter of 1 mm) as a nucleating agent is studied. This study focuses on crystallization, but also on the effect on fundamental properties (i.e., thermal stability) and selected end-use properties (i.e., color, opacity, tensile properties, and gas permeability), to assess its applicability for food packaging purpose...

  20. One-pot synthesis of NiAl-CO3 LDH anti-corrosion coatings from CO2-saturated precursors

    OpenAIRE

    Liu, Yi; Yu, Tongwen; Cai, Rui; Li, Yanshuo; Yang, Weishen; Caro, Juergen

    2015-01-01

    Anti-corrosive coatings based on layered double hydroxides (LDHs) have been considered as promising alternatives to conventional chromate-containing conversion coatings. Among various LDHs, carbonate-intercalated LDH coatings with a c-axis preferred orientation should be the optimum structure for protecting metals against corrosion. Herein we successfully prepared NiAl–CO3 LDH coatings on aluminium plates in one step. Particularly it was found that CO2 dissolved in the precursor solution exer...

  1. Preparation Method of Co3O4 Nanoparticles Using Degreasing Cotton and Their Electrochemical Performances in Supercapacitors

    OpenAIRE

    Hongyan Xu; Libo Gao; Qiang Zhang; Junyang Li; Jiangtao Diwu; Xiujian Chou; Jun Tang; Chenyang Xue

    2014-01-01

    Co3O4 nanoparticles were fabricated by a novel, facile, and environment-friendly carbon-assisted method using degreasing cotton. Structural and morphological characterizations were performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The component of the sample obtained at different temperatures was measured by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Nitrogen adsorption and d...

  2. A Contrastive Study on Physical Properties and Application of CaCO3 in Yongfeng County of Jiangxi Province%江西永丰CaCO3物理性能及在塑料中的应用对比研究

    Institute of Scientific and Technical Information of China (English)

    王锡臣; 徐同考

    2009-01-01

    选用四川和广西具有代表性的CaCO3矿源和CaCO3粉与江西永丰CaCO3的基本性能和在塑料中的应用效果进行对比分析.结果表明:江西永丰CaCO3的白度不如四川、广西两地,而吸油值比其小;江西永丰的CaCO3填充PP样品的力学性能要比其它两地略高;CaCO3填充PE膜的力学性能、透光度与雾度,三地区的CaCO3难分伯仲.

  3. 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.

  4. Synthesis, and molecular sensing behavior of fac-[Re(CO)3(κ2-N,N-dpksc)Cl], dpksc = di-2-pyridyl ketone semicarbazone

    Science.gov (United States)

    Bakir, Mohammed; Brown, Ordel

    2013-01-01

    When [Re(CO)5Cl] was allowed to react with di-2-pyridyl ketone semicarbazone hydrochloride (dpksc.HCl) in refluxing toluene, fac-[Re(CO)3(κ2-N,N-dpksc)Cl] was isolated. The identity of fac-[Re(CO)3(κ2-N,N-dpksc)Cl] was elucidated from the results of its elemental analysis and confirmed using a number of spectroscopic measurements. Spectroscopic measurements done on non-aqueous solvents divulged sensitivity of fac-[Re(CO)3(κ2-N,N-dpksc)Cl] to changes in its surroundings. 1H NMR studies revealed significant solvent dependence as manifested by the chemical shift variations; the exchange of the amine protons with solvent deuterium in CDCl3 and d6-acetone; the temperature dependence of the chemical shifts of the amine and amide protons and insignificant temperature dependence of the aromatic proton. The electronic absorption spectra of fac-[Re(CO)3(κ2-N,N-dpksc)Cl] measured on non-aqueous solvents disclosed two high energy intra-ligand charge transfer (ILCT) transitions. Optical measurements performed on protophilic solutions of fac-[Re(CO)3(κ2-N,N-dpksc)Cl] in the presence of bases and acids showed the appearance and disappearance of a low energy ILCT electronic transitions and established reversible inter-conversion between fac-[Re(CO)3(κ2-N,N-dpksc)Cl] and its conjugate base, fac-[Re(CO)3(κ2-N,N-dpksc-H)Cl]-. Thermo-optical measurements done on protophilic solutions of fac-[Re(CO)3(κ2-N,N-dpksc)Cl] disclosed the absence of thermal acid-base inter-conversion between fac-[Re(CO)3(κ2-N,N-dpksc)Cl] and fac-[Re(CO)3(κ2-N,N-dpksc-H)Cl]- and established reversible electronic transfer between the high energy electronic transitions of fac-[Re(CO)3(κ2-N,N-dpksc)Cl]. Optosensing measurements done on protophilic solutions of fac-[Re(CO)3(κ2-N,N-dpksc)Cl] showed acids and bases in concentrations as low as 1.00 × 10-10 M can be detected and determined using protophilic solutions of of fac-[Re(CO)3(κ2-N,N-dpksc)Cl]. Electrochemical measurements on dmf solutions of fac-[Re(CO

  5. 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.

  6. 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.

  7. Neutral 99mTc(CO)3 complexes of 'clicked' nitroimidazoles for the detection of tumor hypoxia

    International Nuclear Information System (INIS)

    In the present work, three neutral 99mTc(CO)3 complexes of nitroimidazole were synthesized and their potential to detect tumor hypoxia is evaluated in vivo. Triazole derivatives of 2-, 4- and 5-nitroimidazole were synthesized via 'click chemistry' route. The ligands synthesized were characterized and subsequently radiolabeled using [99mTc(CO)3(H2O)3]+ precursor complex to obtain corresponding neutral 99mTc(CO)3 complexes in [90 % radio chemical purity. The complexes were subsequently evaluated in Swiss mice bearing fibrosarcoma tumor and in vivo distribution observed was thoroughly analyzed. All complexes showed uptake in tumor, however, contrary to general expectations, the 5-nitroimidazole complex showed significantly higher tumor uptake (p/0.05) at 30 min and 60 min p.i., compared to the 2-nitroimidazole counterpart. Though a conclusive explanation for this observation could not be obtained, present study underlined the significance of evaluating nitroimidazole radiotracers other than 2-nitroimidazole for detecting tissue hypoxia. (author)

  8. 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.

  9. 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.

  10. 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.

  11. Enhanced rate performance of mesoporous Co(3)O(4) nanosheet supercapacitor electrodes by hydrous RuO(2) nanoparticle decoration.

    Science.gov (United States)

    Rakhi, R B; Chen, Wei; Hedhili, M N; Cha, Dongkyu; Alshareef, H N

    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 RuO2 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. PMID:24580967

  12. 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.

  13. Facile synthesis of core-shell structured PANI-Co3O4 nanocomposites with superior electrochemical performance in supercapacitors

    Science.gov (United States)

    Hai, Zhenyin; Gao, Libo; Zhang, Qiang; Xu, Hongyan; Cui, Danfeng; Zhang, Zengxing; Tsoukalas, Dimitris; Tang, Jun; Yan, Shubin; Xue, Chenyang

    2016-01-01

    Core-shell structured PANI-Co3O4 nanocomposites for supercapacitor applications were synthesized by combination of carbon-assisted method and in situ polymerization method. The crystalline structure, optical band gap, morphology, and hydrophilic property, as the major factors affecting the performances of supercapacitors, were investigated by X-ray diffraction (XRD), UV-vis spectrophotometry (UV-vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and water contact angle (WCA). The core-shell structured PANI-Co3O4 nanocomposites are characterized by amorphous PANI, small bandgaps, large surface area and favorable hydrophilicity, which indicates the superior electrochemical performances of the nanocomposites as electrode material for supercapacitors. Cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS) measurements were conducted in 6 M KOH aqueous solution to evaluate the electrochemical performances. The results shows that core-shell structured PANI-Co3O4 nanocomposites exhibit a high specific capacitance of 1184 F g-1 at 1.25 A g-1, excellent cycling stability of a capacitance retention of 84.9% after 1000 galvanostatic charge/discharge cycles, good electrical conductivity and ion diffusion behavior.

  14. Preparation Method of Co3O4 Nanoparticles Using Degreasing Cotton and Their Electrochemical Performances in Supercapacitors

    Directory of Open Access Journals (Sweden)

    Hongyan Xu

    2014-01-01

    Full Text Available Co3O4 nanoparticles were fabricated by a novel, facile, and environment-friendly carbon-assisted method using degreasing cotton. Structural and morphological characterizations were performed using X-ray diffraction (XRD, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. The component of the sample obtained at different temperatures was measured by Fourier transform infrared spectroscopy (FTIR and X-ray photoelectron spectroscopy (XPS. Nitrogen adsorption and desorption isotherms were utilized to reveal the specific surface areas. The formation mechanism of Co3O4 nanoparticles was also proposed, demonstrating that the additive degreasing cotton played an indispensable role in the process of synthesizing the sample. The resultant Co3O4 sample calcined at 600°C exhibited superior electrochemical performance with better specific capacitance and long-term cycling life, due to its high specific surface areas and pores structures. Additionally, it has been proved that this facile synthetic strategy can be extended to produce other metal oxide materials (e.g., Fe3O4. As a consequence, the carbon-assisted method using degreasing cotton accompanied a promising prospect for practical application.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Green synthesis of Co3O4 nanoparticles and their applications in thermal decomposition of ammonium perchlorate and dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Co3O4 NPs were synthesized from the leaves extract of plant Calotropis gigantea. • Green synthesis of Co3O4 NPs is a cost effective and eco-friendly route. • Faster thermal decomposition of AP occurred in presence of the green synthesized Co3O4 NPs. • A high burning rate of CSP was observed. • Green synthesized Co3O4 NPs displays the good electrocatalytic activity to reduction of I3− to I− ions. - Abstract: In this paper, we report on the green synthesis of cobalt oxide nanoparticles (Co3O4 NPs) using leaves extract of plant Calotropis gigantea and characterize by X-ray diffraction (XRD), UV–vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). The green synthesized Co3O4 NPs showed excellent catalytic effect on the thermal decomposition of ammonium perchlorate (AP) and burning rate of composite solid propellants (CSPs). Kinetics of slow and rapid thermal decomposition has been investigated by isoconversional and ignition delay methods, respectively. Moreover, the electrocatalytic performance of green synthesized Co3O4 NPs in dye-sensitized solar cells (DSSC) has also been evaluated. The cyclic voltametry measurement shows good electrocatalytic activity of Co3O4 NPs toward the reduction of I3− to I− ions

  20. The Conductivity of Aqueous K2CO3 at Elevated Temperatures and Pressures, Measured using the AC van der Pauw Technique

    DEFF Research Database (Denmark)

    Mollerup, Pia Lolk; Christiansen, Ane Sælland; Bonanos, Nikolaos;

    2013-01-01

    Conductivity measurements of aqueous K2CO3 were performed using the van der Pauw method and a specially designed sample holder with Pt wires as electrodes. The resistance was measured using alternating current. The conductivity of 10-50 wt% aqueous K2CO3 was measured at room temperature and ambie...

  1. 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...

  2. 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.

  3. 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.

  4. PP/CaCO3复合材料的制备及性能研究%Preparation and performance of polypropylene and calcium carbonate composite material

    Institute of Scientific and Technical Information of China (English)

    刘建波

    2016-01-01

    在聚丙烯(PP)中添加CaCO3进行填充改性,研究了不同含量、不同颗粒级配的CaCO3,对复合材料(PP/Ca-CO3)力学性能和缺口冲击断面形貌以及流变性能的影响,并采用偏光显微镜(PLM)、广角X射线衍射仪(WAXD)、扫描电镜(SEM),对PP/WCaCO3的结晶形态进行表征.结果表明,在微米CaCO3(m-CaC03)和纳米CaCO3(n-CaC03)的复配比例m(m-CaC03):m(n-CaCO3)=3:1,且复配CaCO3(C-CaC03)总添加量为25%时,PP/C-CaC03的冲击强度达到12.7kJ/m2,比纯PP提高111.67%.PLM以及WAXD分析表明,在一定程度上,n-CaCO3有β成核剂的作用,加快了PP结晶速率,并使球晶细化,有利于PP/CaCO3的增韧.

  5. 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.

  6. Enhanced biomimetic CO2 sequestration and CaCO3 crystallization using complex encapsulated metal organic framework

    Science.gov (United States)

    Sahoo, Prakash C.; Jang, Young Nam; Lee, Seung Woo

    2013-06-01

    A new biomimetic complex (Co-BBP) that mimics the active site of carbonic anhydrase (CA) was prepared by the coordination of cobalt (II) with 2, 6-bis(2-benzimidazolyl) and was encapsulated into a metal organic framework (Co-BBP@Tb-MOF). Carbon dioxide (CO2) sequestration was carried out via an in vitro mineralization approach using these biomimetic catalysts. The biomimetic catalysts were expected to enhance CO2 hydration and calcium carbonate (CaCO3) crystallization based on the same mechanism as that of CA.

  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. Síntesis del Compuesto Homotipo de la Dolomita PbMg(CO3)2 a Temperatura Ambiente

    OpenAIRE

    Pimentel, C.; Pina, Carlos M

    2015-01-01

    La realización de experimentos de síntesis de carbonatos con estructura tipo dolomita se ha revelado como una interesante manera de estudiar los posibles procesos de formación de dolomita en la naturaleza, toda vez que este mineral se resiste a ser sintetizado en el laboratorioa temperatura ambiente (Lippmann, 1973, Hood et al., 1974; Morrow & Ricketts, 1986; Böttcher, 2000; Pimentel & Pina, 2014a,b). Entre las fases con estructura análoga a la de la dolomita, la norsethita [BaMg(CO3)2] y ...

  9. 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

  10. 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.

  11. Pengaruh Pengaturan pH dengan CaCO3 terhadap Produksi Asam Laktat dari Glukosa oleh Rhizopus oryzae

    OpenAIRE

    ARTINI PANGASTUTI; TJAHJADI PURWOKO; IDAYU RIA PRAMUDYANTI,

    2004-01-01

    The aim of this research was to study lactic acid product from glucose by R.oryzae without pH controlling, with pH 5 controlling, pH 6 controlling, and pH 7 controlling. Control of pH was done to avoid the accumulation of organic acids that could make pH decreasing on fermentation medium. This research used a treatment medium without pH controlling and three treatment medium with pH controlling. A treatment medium without pH controlling was added by 0.1 g CaCO3 before fermentation while treat...

  12. Production of poly-3-hydroxybutyrate (P3HB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) P(3HB-co-3HV) from synthetic wastewater using Hydrogenophaga palleronii.

    Science.gov (United States)

    Venkateswar Reddy, M; Mawatari, Yasuteru; Yajima, Yuka; Satoh, Kohki; Venkata Mohan, S; Chang, Young-Cheol

    2016-09-01

    In the present study, synthetic wastewater (SW) was used for production of poly-3-hydroxybutyrate (P3HB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) P(3HB-co-3HV) using the bacteria Hydrogenophaga palleronii. SW at various volatile fatty acids concentrations (5-60g/l) was evaluated for the growth and biopolymer production using H. palleronii. Substrate degradation was analyzed using total organic carbon (TOC) analyzer and high pressure liquid chromatography (HPLC). H. palleronii showed highest and lowest removal of TOC at 5g/l (88±4%) and 60g/l (15±6%) respectively. Among all the concentrations evaluated, bacteria showed highest biopolymer production with 20g/l (63±5%), followed by 30g/l (58±3%) and 40g/l (56±2%). Lowest biopolymer production was observed at 5g/l concentration (21±3%). Structure, molecular weight, and thermal properties of the produced biopolymer were analyzed. These results denoted that the strain H. palleronii can be used for degradation of high concentration of volatile fatty acids persistent in wastewaters and their subsequent conversion into useable biopolymers. PMID:26995321

  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. Crystal and electronic structure changes during the charge-discharge process of Na4Co3(PO4)2P2O7

    Science.gov (United States)

    Moriwake, Hiroki; Kuwabara, Akihide; Fisher, Craig A. J.; Nose, Masafumi; Nakayama, Hideki; Nakanishi, Shinji; Iba, Hideki; Ikuhara, Yuichi

    2016-09-01

    Sodium-ion batteries offer a potential solution to the problem of limited lithium resources, and the newly developed positive electrode material Na4Co3(PO4)2P2O7 is attracting significant attention due to its high rate, high capacity, and high voltage compared to other sodium-ion battery materials. However, details of its electronic structure and its charge/discharge behavior are still uncertain. Here we report detailed first-principles calculations of the desodiation behavior of Na4Co3(PO4)2P2O7 using the GGA + U formalism of density functional theory. Assuming a stepwise desodiation process, removal of Na down to NaCo3(PO4)2P2O7 is found to be accompanied by oxidation of Co2+ to Co3+. Further removal of Na to give Co3(PO4)2P2O7 requires oxidation of oxygen 2p orbitals in the P2O7 polyhedra instead of Co3+ being oxidized to Co4+. The holes thus formed are expected to be strongly self-trapped, rendering them immobile at room temperature. At the same time, a large volume shrinkage is observed during this last desodiation step, constricting the Na migration channels. These two factors may explain the difficulty encountered experimentally in removing all Na from Na4Co3(PO4)2P2O7.

  15. Metal-assisted in situ formation of a tridentate acetylacetone ligand for complexation of fac-Re(CO)3+ for radiopharmaceutical applications.

    Science.gov (United States)

    Benny, Paul D; Fugate, Glenn A; Barden, Adam O; Morley, Jennifer E; Silva-Lopez, Elsa; Twamley, Brendan

    2008-04-01

    Reaction of [NEt4]2[ReBr3(CO)3] with 2,4-pentanedione (acac) yields a complex of the type fac-Re(acac)(OH2)(CO)3 (1) under aqueous conditions. 1 was further reacted with a monodentate ligand (pyridine) to yield a fac-Re(acac)(pyridine)(CO)3 complex (2). Complex 1 was found to react with primary amines to generate a Schiff base (imine) in aqueous solutions. When a mixed-nitrogen donor bidentate ligand, 2-(2-aminoethyl)pyridine, that has different coordination affinities for fac-Re(acac)(OH2)(CO)3 was utilized, a unique tridentate ligand was formed in situ utilizing a metal-assisted Schiff base formation to yield a complex fac-Re(CO)3(3[(2-phenylethyl)imino]-2-pentanone) (3). Tridentate ligand formation was found to occur only with the Re-coordinated acac ligand. Reactions of acac with fac-Re(CO)3Br(2-(2-aminoethyl)pyridine) (4) or a mixture of [NEt4]2[ReBr3(CO)3], acac, and 2-(2-aminoethyl)pyridine did not yield the formation of complex 3 in water. PMID:18298058

  16. Co3O4-SnO2 Hollow Heteronanostructures: Facile Control of Gas Selectivity by Compositional Tuning of Sensing Materials via Galvanic Replacement.

    Science.gov (United States)

    Jeong, Hyun-Mook; Kim, Jae-Hyeok; Jeong, Seong-Yong; Kwak, Chang-Hoon; Lee, Jong-Heun

    2016-03-30

    Co3O4 hollow spheres prepared by ultrasonic spray pyrolysis were converted into Co3O4-SnO2 core-shell hollow spheres by galvanic replacement with subsequent calcination at 450 °C for 2 h for gas sensor applications. Gas selectivity of the obtained spheres can be controlled by varying the amount of SnO2 shells (14.6, 24.3, and 43.3 at. %) and sensor temperatures. Co3O4 sensors possess an ability to selectively detect ethanol at 275 °C. When the amount of SnO2 shells was increased to 14.6 and 24.3 at. %, highly selective detection of xylene and methylbenzenes (xylene + toluene) was achieved at 275 and 300 °C, respectively. Good selectivity of Co3O4 hollow spheres to ethanol can be explained by a catalytic activity of Co3O4; whereas high selectivity of Co3O4-SnO2 core-shell hollow spheres to methylbenzenes is attributed to a synergistic effect of catalytic SnO2 and Co3O4 and promotion of gas sensing reactions by a pore-size control of microreactors. PMID:26964735

  17. Health-related quality of life of people living with HIV followed up in hospitals in France: comparing trends and correlates between 2003 and 2011 (ANRS-VESPA and VESPA2 national surveys).

    Science.gov (United States)

    Douab, Taoufiq; Marcellin, Fabienne; Vilotitch, Antoine; Protopopescu, Camelia; Préau, Marie; Suzan-Monti, Marie; Sagaon-Teyssier, Luis; Lert, France; Carrieri, Maria Patrizia; Dray-Spira, Rosemary; Spire, Bruno

    2014-01-01

    In recent years, France has witnessed both structural changes in the population of people living with HIV and a relative improvement in the social representation of HIV infection. However, potential changes in people's day-to-day experience with HIV have not been documented. We used data from the national surveys ANRS-VESPA (2003) and VESPA2 (2011) to compare the levels and patterns of correlates of health-related quality of life (HRQL) in adult HIV-infected patients followed up in French hospitals over a period of eight years. Mean physical and mental SF-12 scores were compared (VESPA, n = 2072; and VESPA2, n = 2267) using analysis of variance (ANOVA) F tests. Heckman regression models were then used to identify independent correlates of physical and mental quality of life in the two surveys, while accounting for possible bias due to missing score values. A common set of potential socio-demographic, clinical, behavioral, and psychosocial correlates was tested. Individuals reported a decrease in physical quality of life in VESPA2 compared with VESPA (mean score (standard error): 47.5 (0.2) versus 49.6 (0.2), p mental HRQL (44.3 (0.3) versus 42.3 (0.3), p mental quality of life. Older age and unemployment were independently associated with impaired physical quality of life. Immigrants from Sub-Saharan Africa reported better mental quality of life. Findings show that quality of life levels in adult HIV-infected patients followed up at hospital in France has significantly, yet modestly, changed in recent years. However, the pattern of quality of life correlates has remained relatively stable. The impact of patient-provider relationships on self-reported outcomes is confirmed. Further research is needed to identify potential differences in quality of life correlates in specific subgroups of patients, such as men who have sex with men, women, immigrants, and injecting drug users.

  18. Impact of IL28B, APOH and ITPA Polymorphisms on Efficacy and Safety of TVR- or BOC-Based Triple Therapy in Treatment-Experienced HCV-1 Patients with Compensated Cirrhosis from the ANRS CO20-CUPIC Study.

    Directory of Open Access Journals (Sweden)

    Frédégonde About

    Full Text Available Human genetic factors influence the outcome of pegylated interferon and ribavirin hepatitis C therapy. We explored the role of IL28B, APOH and ITPA SNPs on the outcomes of triple therapy including telaprevir or boceprevir in patients with compensated cirrhosis chronically infected with HCV-1.A total of 256 HCV-1 Caucasian treatment-experienced patients with compensated cirrhosis from the ANRS CO20-CUPIC cohort were genotyped for a total of 10 candidate SNPs in IL28B (rs12979860 and rs368234815, APOH (rs8178822, rs12944940, rs10048158, rs52797880, rs1801689 and rs1801690 and ITPA (rs1127354 and rs7270101. We tested the association of IL28B and APOH SNPs with sustained virological response and of ITPA SNPs with anemia related phenotypes by means of logistic regression assuming an additive genetic model.None of the six APOH SNPs were associated with sustained virological response. The favorable alleles of the IL28B SNPs rs12979860 and rs368234815 were associated with sustained virological response (rs12979860: OR = 2.35[1.50-3.70], P = 2x10(-4. Refined analysis showed that the effect of IL28B SNPs on sustained virological response was restricted to prior PegIFN/RBV relapse (OR = 3.80[1.82-8.92], P = 8x10(-4. We also confirmed the association between ITPA low activity alleles and protection against early hemoglobin decline in triple therapy (P = 2x10(-5.Our results suggest that the screening of rs12979860 may remain interesting for decision making in prior relapse HCV-1 Caucasian patients with compensated cirrhosis eligible for a telaprevir- or boceprevir-based therapy.

  19. Impact of IL28B, APOH and ITPA Polymorphisms on Efficacy and Safety of TVR- or BOC-Based Triple Therapy in Treatment-Experienced HCV-1 Patients with Compensated Cirrhosis from the ANRS CO20-CUPIC Study

    Science.gov (United States)

    About, Frédégonde; Oudot-Mellakh, Tiphaine; Niay, Jonathan; Rabiéga, Pascaline; Pedergnana, Vincent; Duffy, Darragh; Sultanik, Philippe; Cagnot, Carole; Carrat, Fabrice; Marcellin, Patrick; Zoulim, Fabien; Larrey, Dominique; Hézode, Christophe; Fontaine, Hélène; Bronowicki, Jean-Pierre; Pol, Stanislas; Albert, Matthew L.; Theodorou, Ioannis

    2015-01-01

    Background Human genetic factors influence the outcome of pegylated interferon and ribavirin hepatitis C therapy. We explored the role of IL28B, APOH and ITPA SNPs on the outcomes of triple therapy including telaprevir or boceprevir in patients with compensated cirrhosis chronically infected with HCV-1. Patients and Methods A total of 256 HCV-1 Caucasian treatment-experienced patients with compensated cirrhosis from the ANRS CO20-CUPIC cohort were genotyped for a total of 10 candidate SNPs in IL28B (rs12979860 and rs368234815), APOH (rs8178822, rs12944940, rs10048158, rs52797880, rs1801689 and rs1801690) and ITPA (rs1127354 and rs7270101). We tested the association of IL28B and APOH SNPs with sustained virological response and of ITPA SNPs with anemia related phenotypes by means of logistic regression assuming an additive genetic model. Results None of the six APOH SNPs were associated with sustained virological response. The favorable alleles of the IL28B SNPs rs12979860 and rs368234815 were associated with sustained virological response (rs12979860: OR = 2.35[1.50–3.70], P = 2x10-4). Refined analysis showed that the effect of IL28B SNPs on sustained virological response was restricted to prior PegIFN/RBV relapse (OR = 3.80[1.82–8.92], P = 8x10-4). We also confirmed the association between ITPA low activity alleles and protection against early hemoglobin decline in triple therapy (P = 2x10-5). Conclusion Our results suggest that the screening of rs12979860 may remain interesting for decision making in prior relapse HCV-1 Caucasian patients with compensated cirrhosis eligible for a telaprevir- or boceprevir-based therapy. PMID:26670100

  20. Synthesis of flower-like, pinon-like and faceted nanoplates (BiO)2CO3 micro/nanostructures with morphology-dependent photocatalytic activity

    International Nuclear Information System (INIS)

    The flower-like, pinon-like and faceted nanoplates (BiO)2CO3 micro/nanostructures were fabricated by a one-pot template-free method based on hydrothermal treatment of the aqueous mixture of bismuth citrate and sodium carbonate. The morphology of (BiO)2CO3 can be simply controlled by the reaction temperature. X-ray diffraction, scanning electron microscopy, UV–vis diffuse reflection spectra, and photoluminescence spectra were applied to analyze the microstructures and properties of the samples. The flower-like and pinon-like (BiO)2CO3 superstructures were hierarchically self-assembled by nanoplates and showed increased light absorption owing to the multiple light reflection between the nanoplates. The thickness of nanoplates was increased with the increasing reaction temperatures due to the preferred growth along the (110) plane. The (BiO)2CO3 with various micro/nanostructures showed morphology-dependent photocatalytic activity toward removal of aqueous RhB. The as-prepared flower-like (BiO)2CO3 microspheres exhibited highest photocatalytic activity due to the large surface area, increased light absorption, enhanced charge carriers separation, and special architectures of hierarchical nanoplates microspheres, exceeding that of the P25. - Graphical abstract: Flower-like, pinon-like and faceted nanoplates (BiO)2CO3 micro/nanostructures with morphology-dependent photocatalytic activity can be selectively synthesized by controlling the hydrothermal temperature. - Highlights: • Flower-like, pinon-like and faceted nanoplates (BiO)2CO3 were synthesized. • The synthesis was conducted by facile template-free hydrothermal method. • The (BiO)2CO3 superstructures were hierarchically self-assembled by nanoplates. • The thickness of nanoplates was increased with the increased reaction temperatures. • (BiO)2CO3 micro/nanostructures showed morphology-dependent photocatalytic activity

  1. 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.

  2. 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.

  3. Catalytic performance of Mn3O4 and Co3O4 nanocrystals prepared by sonochemical method in epoxidation of styrene and cyclooctene

    International Nuclear Information System (INIS)

    A simple sonochemical method was developed to synthesis uniform sphere-like Co3O4 and Mn3O4 nanocrystals. Epoxidation of styrene and cyclooctene by anhydrous tert-butyl hydroperoxide over the prepared Co3O4 and Mn3O4 nanocatalysts was investigated. The results of conversion activity were compared with bulk Co3O4 and Mn3O4. Under optimized reaction conditions, the nanocatalysts showed a superior catalytic performance as compared to the bulk catalysts. Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and BET surface area, were used to characterize and investigate the nanocatalysts.

  4. Formation of ozone in the reaction between the ozonide radical ion, O3-, and the carbonate radical ion, CO3-, in aqueous alkaline solutions

    International Nuclear Information System (INIS)

    Ozone forms in aqueous alkaline solutions by a reaction between the O3- and CO3- radical ions. This reaction has been demonstrated under conditions favorable for the generation of suitable concentrations of these ions by a high-pressure pulse radiolysis technique. The reaction is O3- + CO3- → O3 + CO32-. Its rate constant k/sub (O3-+CO3-)/ of (6 +- 2) x 107 dm3 mol-1 s-1 has been determined by computer simulation of the reactions involved

  5. Enhancement of CO(3-2)/CO(1-0) ratios and star formation efficiencies in supergiant H II regions

    International Nuclear Information System (INIS)

    We present evidence that super giant H II regions (GHRs) and other disk regions of the nearby spiral galaxy, M33, occupy distinct locations in the correlation between molecular gas, ΣH2, and the star formation rate surface density, ΣSFR. This result is based on wide-field and high-sensitivity CO(3-2) observations at 100 pc resolution. Star formation efficiencies (SFEs), defined as ΣSFR/ΣH2, in GHRs are found to be ∼1 dex higher than in other disk regions. The CO(3-2)/CO(1-0) integrated intensity ratio, R 3-2/1-0, is also higher than the average over the disk. Such high SFEs and R 3-2/1-0 can reach the values found in starburst galaxies, which suggests that GHRs may be the elements building up a larger-scale starburst region. Three possible contributions to high SFEs in GHRs are investigated: (1) the I CO-N(H2) conversion factor, (2) the dense gas fraction traced by R 3-2/1-0, and (3) the initial mass function (IMF). We conclude that these starburst-like properties in GHRs can be interpreted by a combination of both a top-heavy IMF and a high dense gas fraction, but not by changes in the I CO-N(H2) conversion factor.

  6. 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. PMID:26639519

  7. Electron Spin Resonance of Ascorbyl (Vitamin C) Radicals in Synthetic CaCO3 by UV Irradiation

    Science.gov (United States)

    Sato, Hideo; Tani, Atsushi; Ikeya, Motoji

    2003-02-01

    Free radicals ascribed to ascorbic acid (AscH2), vitamin C, in the solid matrix of synthetic calcium carbonate have been studied using electron spin resonance (ESR) after UV irradiation. A new ESR signal with g-factors of g\\|=2.0024 and g\\bot=2.0053 was found together with a broad singlet signal around g=2.005 and a doublet signal at g=2.0053 separated by 0.18 mT due to the ascorbyl radical (Asc•-). The molecular orbitals of Asc•- and two other types of ascorbyl radical (AscH•-) were calculated using the semi-empirical PM3 unrestricted Hartree-Fock (UHF) method, which indicated that the hyperfine splitting due to hydrogen bonded to one of the carbons in the pentagonal ring was dominant. The axial signal was ascribed to AscH•-, while the doublet signal was ascribed to Asc•- in CaCO3. Possible pharmaceutical and nutritional applications of embedding unstable active molecules into the crystalline lattice of CaCO3 and a new nondestructive method for determination of vitamin C contents are discussed because the vitamin C has higher thermal stability in the carbonate than that in aqueous solution.

  8. 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.

  9. X-Ray Diffraction and Raman Spectroscopy Analysis of Siderite FeCO3 Under High Pressure (Invited)

    Science.gov (United States)

    Mu, K.; Filipovitch, N. B.; Mao, W. L.

    2009-12-01

    Scientists have been searching for methods to mitigate the devastating effects of global warming—one of these methods is carbon sequestration, or capture and storage of carbon dioxide that has been released into the atmosphere. Understanding the deep Earth carbon cycle gives insight into the long term storage of carbon within our planet and could provide guidance for carbon sequestration. The area of high pressure mineral physics focuses on the study of mineral behavior of the conditions found within the Earth’s interior. Researchers use pressure generating devices like diamond anvil cells to compress samples in order to simulate the conditions within our planet. We studied the mineral siderite (FeCO3), an iron-rich carbonate mineral that may be an important reservoir for carbon storage within the Earth. We studied the structure change and stability of a powdered siderite (FeCO3) sample in a diamond anvil cell up to 40GPa using X-ray diffraction and Raman spectroscopy. The Raman data recorded a linear peak shift as a function of pressure for pressures up to 38 GPa, peak broadening with increasing pressure, and no new peaks or disappearance of peaks over the region studied. Our X-ray diffraction results indicated a possible phase transition at approximately 13 GPa. At this pressure, several peaks split. This new high pressure phase may play a significant role in deep Earth carbon storage.

  10. Reductive smelting of spent lead-acid battery colloid sludge in a molten Na2CO3 salt

    Science.gov (United States)

    Hu, Yu-jie; Tang, Chao-bo; Tang, Mo-tang; Chen, Yong-ming

    2015-08-01

    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 results suggested that increases in temperature and salt dosage improved the direct recovery rate of lead. XRD results and thermodynamic calculations 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.

  11. 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.

  12. Removal of indigo carmine dye from water to Mg-Al-CO3-calcined layered double hydroxides

    International Nuclear Information System (INIS)

    Layered double hydroxides (LDHs) calcined, denoted as CLDHs, have been shown to recover their original layered structure in the presence of appropriate anions. In the light of this so-called 'memory effect', the removal of indigo carmine (IC), an anionic dye, from aqueous solution by calcined Mg-Al-CO3 LDHs was investigated in batch mode. We looked at the influence of pH values, dye-adsorbent contact time, initial dye concentration and various temperatures of heating of LDHs on the decolorization rate of IC. The adsorption isotherms, described by Freundlich model are L-type. The characterization of the solids CLDHs, both fresh and after removal of IC, by X-ray diffraction and infrared spectroscopy shows that the IC adsorption on CLDHs is enhanced by reconstruction of a matrix hydrotalcite intercaled by the dye, and the intercalation of the organic ion was clearly evidenced by the net increase in the basal spacing from 0.76 nm for [Mg-Al-CO3] to 2.13 nm for the organic derivative

  13. 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. PMID:18853819

  14. Enhancement of CO(3-2)/CO(1-0) ratios and star formation efficiencies in supergiant H II regions

    Energy Technology Data Exchange (ETDEWEB)

    Miura, Rie E.; Espada, Daniel; Komugi, Shinya; Nakanishi, Kouichiro; Sawada, Tsuyoshi; Fujii, Kosuke; Kawabe, Ryohei [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Kohno, Kotaro [Institute of Astronomy, School of Science, The University of Tokyo, Osawa, Mitaka, Tokyo 181-0015 (Japan); Tosaki, Tomoka [Joetsu University of Education, Yamayashiki-machi, Joetsu, Niigata 943-8512 (Japan); Hirota, Akihiko; Minamidani, Tetsuhiro [Nobeyama Radio Observatory, Minamimaki, Minamisaku, Nagano 384-1805 (Japan); Okumura, Sachiko K. [Department of Mathematical and Physical Sciences, Faculty of Science, Japan Woman' s University, Mejirodai 2-8-1, Bunkyo, Tokyo 112-8681 (Japan); Kuno, Nario [Department of Astronomical Science, The Graduate University for Advanced Studies (Sokendai), 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Muraoka, Kazuyuki; Onodera, Sachiko [Osaka Prefecture University, Gakuen 1-1, Sakai, Osaka 599-8531 (Japan); Kaneko, Hiroyuki, E-mail: rie.miura@nao.ac.jp [Department of Physics, Meisei University, Hino, Tokyo 191-8506 (Japan)

    2014-06-20

    We present evidence that super giant H II regions (GHRs) and other disk regions of the nearby spiral galaxy, M33, occupy distinct locations in the correlation between molecular gas, Σ{sub H{sub 2}}, and the star formation rate surface density, Σ{sub SFR}. This result is based on wide-field and high-sensitivity CO(3-2) observations at 100 pc resolution. Star formation efficiencies (SFEs), defined as Σ{sub SFR}/Σ{sub H{sub 2}}, in GHRs are found to be ∼1 dex higher than in other disk regions. The CO(3-2)/CO(1-0) integrated intensity ratio, R {sub 3-2/1-0}, is also higher than the average over the disk. Such high SFEs and R {sub 3-2/1-0} can reach the values found in starburst galaxies, which suggests that GHRs may be the elements building up a larger-scale starburst region. Three possible contributions to high SFEs in GHRs are investigated: (1) the I {sub CO}-N(H{sub 2}) conversion factor, (2) the dense gas fraction traced by R {sub 3-2/1-0}, and (3) the initial mass function (IMF). We conclude that these starburst-like properties in GHRs can be interpreted by a combination of both a top-heavy IMF and a high dense gas fraction, but not by changes in the I {sub CO}-N(H{sub 2}) conversion factor.

  15. Recovery of actinides from TBP-Na2Co3 scrub-waste solutions: the ARALEX process

    International Nuclear Information System (INIS)

    A flowsheet for the recovery of actinides from TBP-Na2CO3 scrub-waste solutions has been developed, based on batch extraction data, and tested, using laboratory-scale countercurrent extraction techniques. The process, called the ARALEX process, uses 2-ethyl-1-hexanol (2-EHOH) to extract the TBP degradation products (HDBP and H2MBP) from acidified Na2CO3 scrub waste leaving the actinides in the aqueous phase. Dibutyl and monobutyl phosphoric acids are attached to the 2-EHOH molecules through hydrogen bonds, which also diminish the ability of the HDBP and H2MBP to complex actinides. Thus all actinides remain in the aqueous raffinate. Dilute sodium hydroxide solutions can be used to back-extract the dibutyl and monobutyl phosphoric acid esters as their sodium salts. The 2-EHOH can then be recycled. After extraction of the acidified carbonate waste with 2-EHOH, the actinides may be readily extracted from the raffinate with DHDECMP or, in the case of tetra- and hexavalent actinides, with TBP. The ARALEX process can also be applied to other actinide waste streams which contain appreciable concentrations of polar organic compounds (e.g., detergents) that interfere with conventional actinide ion exchange and liquid-liquid extraction procedures. 20 figures, 6 tables

  16. Needle-like Co3O4 anchored on the graphene with enhanced electrochemical performance for aqueous supercapacitors.

    Science.gov (United States)

    Guan, Qun; Cheng, Jianli; Wang, Bin; Ni, Wei; Gu, Guifang; Li, Xiaodong; Huang, Ling; Yang, Guangcheng; Nie, Fude

    2014-05-28

    We synthesized the needle-like cobalt oxide/graphene composites with different mass ratios, which are composed of cobalt oxide (Co3O4 or CoO) needle homogeneously anchored on graphene nanosheets as the template, by a facile hydrothermal method. Without the graphene as the template, the cobalt precursor tends to group into urchin-like spheres formed by many fine needles. When used as electrode materials of aqueous supercapacitor, the composites of the needle-like Co3O4/graphene (the mass ratio of graphene oxide(GO) and Co(NO3)2·6H2O is 1:5) exhibit a high specific capacitance of 157.7 F g(-1) at a current density of 0.1 A g(-1) in 2 mol L(-1) KOH aqueous solution as well as good rate capability. Meanwhile, the capacitance retention keeps about 70% of the initial value after 4000 cycles at a current density of 0.2 A g(-1). The enhancement of excellent electrochemical performances may be attributed to the synergistic effect of graphene and cobalt oxide components in the unique multiscale structure of the composites. PMID:24716615

  17. A flexible, transparent and super-long-life supercapacitor based on ultrafine Co3O4 nanocrystal electrodes

    Science.gov (United States)

    Liu, X. Y.; Gao, Y. Q.; Yang, G. W.

    2016-02-01

    Flexible and transparent supercapacitors, as advanced energy storage devices, are essential for the development of innovative wearable electronics because of their unique optical and mechanical qualities. However, all previous designs are based on carbon-based nanostructures like carbon nanotubes and graphene, and these devices usually have poor or short cycling lives. Here, we demonstrate a high-performance, flexible, transparent, and super-long-life supercapacitor made from ultrafine Co3O4 nanocrystals synthesized using a novel process involving laser ablation in liquid. The fabricated flexible and transparent pseudocapacitor exhibits a high capacitance of 177 F g-1 on a mass basis and 6.03 mF cm-2 based on the area of the active material at a scan rate of 1 mV s-1, as well as a super-long cycling life with 100% retention rate after 20 000 cycles. An optical transmittance of up to 51% at a wavelength of 550 nm is achieved, and there are not any obvious changes in the specific capacitance after bending from 0° to 150°, even after bending over 100 times. The integrated electrochemical performance of the Co3O4-based supercapacitor is greatly superior to that of the carbon-based ones reported to date. These findings open the door to applications of transition metal oxides as advanced electrode materials in flexible and transparent pseudocapacitors.

  18. 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.

  19. 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.

  20. 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.