WorldWideScience

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. The renewable energies panorama in Aquitaine

    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 panorama takes stock on the renewable energies development in Aquitaine: photovoltaic, geothermal energy, thermal solar, hydroelectricity and cogeneration. (A.L.B.)

  4. 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.)

  5. 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

  6. The impacts of climate change in Aquitaine

    International Nuclear Information System (INIS)

    This article presents a book which addresses the impacts of climate change in the Aquitaine region by 2030-2050 in order to prepare the adaptation of the main economic sectors. Several fields are addressed: agriculture and wine-growing, forestry, estuaries, coasts and sea resources. The book examines two aspects of climate change due to greenhouse gas emissions: mitigation and adaptation. Two scenarios are studied: a global temperature increase of 2 degrees, and a global temperature increase between 4 and 5 degrees. As examples of this study, this article gives an overview of these issues of mitigation and adaptation in four domains: forests, wine-growing, air quality, and health

  7. [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

  8. 76 FR 61683 - ANR Pipeline Company; Notice of Application

    Science.gov (United States)

    2011-10-05

    ... Energy Regulatory Commission ANR Pipeline Company; Notice of Application Take notice that on September 22, 2011, ANR Pipeline Company (ANR Pipeline), 717 Texas Street, Suite 2400, Houston, Texas 77002-2761... an offshore production platform in Mississippi Canyon Block 194 connecting with approximately...

  9. 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.)

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

    Directory of Open Access Journals (Sweden)

    Isabelle Techoueyres

    2001-10-01

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

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

    OpenAIRE

    Isabelle Techoueyres

    2001-01-01

    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. « La naturopathie en Aquitaine »

    Directory of Open Access Journals (Sweden)

    Marie-Pierre Estager

    2001-10-01

    Full Text Available Cet article sur la naturopathie en Aquitaine et plus précisément la conversion thérapeutique, a été élaboré à partir d’un travail de terrain sur lequel je me suis penchée pendant plusieurs années dans le cadre de ma thèse en anthropologie sociale et culturelle. Je me suis intéressée aux personnes qui sont passées d’un système médical conventionnel à un système de soins alternatif et naturel. En étudiant ce phénomène de « conversion thérapeutique », je les ai suivi dans leur apprentissage en n...

  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. 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...

  15. 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

  16. 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...

  17. 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...

  18. Des pionniers autoconstructeurs aux coopérateurs : histoire des Castors en Aquitaine

    OpenAIRE

    Boustingorry, Julie

    2008-01-01

    In Aquitaine, initiatives known as castorat1, a multi-faceted cooperative movement, represent a variety of alternatives to deal with inadequate public policies, when "civil society" takes action to solve the housing problem by itself. The emergence of a movement of this kind is linked to the acute nature of the housing problem, in a region in which the gradual nature of industrialization, or industrialisation douce2, has not facilitated awareness by the urban elites of the existence of this s...

  19. 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...

  20. 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...

  1. Development of the PETawatt Aquitaine Laser system and new perspectives in physics

    Science.gov (United States)

    Batani, D.; Koenig, M.; Miquel, J. L.; Ducret, J. E.; d'Humieres, E.; Hulin, S.; Caron, J.; Feugeas, J. L.; Nicolai, Ph; Tikhonchuk, V.; Serani, L.; Blanchot, N.; Raffestin, D.; Thfoin-Lantuejoul, I.; Rosse, B.; Reverdin, C.; Duval, A.; Laniesse, F.; Chancé, A.; Dubreuil, D.; Gastineau, B.; Guillard, J. C.; Harrault, F.; Lebœuf, D.; Le Ster, J.-M.; Pès, C.; Toussaint, J.-C.; Leboeuf, X.; Lecherbourg, L.; Szabo, C. I.; Dubois, J.-L.; Lubrano-Lavaderci, F.

    2014-05-01

    The paper describes the preparation of the short-pulse high-energy laser PETawatt Aquitaine Laser (PETAL), which will be coupled to the Laser Megajoule (LMJ) laser of CEA. The LMJ/PETAL facility will be opened for the academic access of European researchers. In parallel, diagnostics are being developed within the PETAL + project and many physical problems are being addressed ranging from the study of the problems of radiation generation and activation issues to the problem of generation of large electromagnetic pulses.

  2. A new Robertsonian translocation in Blonde d'Aquitaine cattle, rob (4; 10)

    OpenAIRE

    Berland HM; Cribiu EP; Bahri-Darwich I; Darré R

    1993-01-01

    L’étude cytogénétique d’une population de bovins Blonde d’Aquitaine a permis de trouver une nouvelle translocation robertsonienne. Les chromosomes impliqués dans cette anomalie ont été déterminés à l’aide des techniques de marquage G (GTG), R (RBG) et C (CBG). Les chromosomes concernés sont le 4 et le 10. L’existence de deux vaches porteuses demi-soeurs de père indique une origine vraisemblablement paternelle de l’anomalie.

  3. 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

  4. 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

  5. [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

  6. 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...

  7. 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...

  8. Measurement of gamma attenuation for ANR end shield model using CaSO4:Dy phosphor

    International Nuclear Information System (INIS)

    Highlights: ► Designing of Advanced Nuclear Reactor (ANR) end shield model. ► Measurement of gamma attenuation factor using CaSO4:Dy TL phosphor. ► Measurement of gamma attenuation factor under different conditions. ► Use of gamma attenuation factor for the actual end shield of ANR. ► Radiation level in the accessible area of ANR well below the permissible limit. - Abstract: In the present study, gamma attenuation factors were measured for End shield model of Advanced Nuclear Reactor (ANR). The model is of the size 700 × 700 × 1250 mm3 and made of steel ball and water mixture with 2 × 2 lattice locations at the centre of the model. The measurements were carried out using CaSO4:Dy TL phosphor. The streaming of gamma rays (includes core gamma, fission product gamma, activation gamma and capture gamma) was found to be attenuated by a factor of about 1500–4000 at a distance of 1125 mm from the incident face of the model, when it is filled with the mixture of water and steel ball. The corresponding exposure rate of streaming gamma rays was found to be about 1.2–2 R/h. The attenuation factors derived from the study was used for the designing of actual End shield for ANR

  9. 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

  10. 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...

  11. 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...

  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. PMID:26119362

  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. Thermoluminescence of CaCO3:Dy and CaCO3:Mn

    International Nuclear Information System (INIS)

    CaCO3 samples doped with Dy and Mn were prepared in the laboratory by co-precipitation techniques. Thermoluminescence and emission spectra of these phosphors were studied and were compared with those of the naturally occuring calcite and undoped CaCO3 samples. Dy-doping seems to give a more efficient phosphor and indicates a possibility of getting a better phosphor by a judicious choice of a rare earth doping of CaCO3. Interesting result have been obtained on the TL glow curve variations of these phosphors with different temperature treatments prior to irradiation. (author)

  16. Radiolysis of Ca14CO3

    International Nuclear Information System (INIS)

    The partition-ion exclusion chromatography is evaluated to analyse non-ionic organic compounds obtained from radiolysis of high specific activity Ca14CO3. The Ca14CO3 was irradiated by β- decay of carbon-14 or by γ rays from a cobalt-60 source. The crystals were dissolved for qualitative and quantitative analysis of the radiolytic products. Formic and oxalic acids were produced in high yields. Glyoxylic, acetic and glycolic acids, formaldehyde and methanol were produced in low yields. Quantitative determination was carried out by liquid scintillation spectroscopy and the chemical yields (G-values) were calculated for the products. Mechanisms of product formation are proposed based on thermal annealing experiments. (Author)

  17. 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...

  18. 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.

  19. 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...

  20. 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

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

    Science.gov (United States)

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

    2013-03-01

    This study aimed to identify dietary behaviors that might be considered as associated factors for overweight or obesity among French adolescents. Forty-nine of the 536 middle and high schools in Aquitaine (southwest of France) were invited to take part in the study. For each school, participating adolescents were selected using stratification by grade. A self-report questionnaire, including information about sex, age, dietary behaviors, physical and sedentary activities, and parental socioeconomic status (SES), was filled in by adolescents during class. Overweight and obesity were defined according to the age- and sex-specific body mass index cutoff points of the International Obesity Task Force. Multivariate analysis (logistic regression) was used to identify independent dietary factors associated with overweight including obesity and obesity alone (adjustment on sex, age, parental SES, and weight status and adolescents' sedentary activity). In addition to parental SES and weight status and adolescents' sedentary activity, some dietary behaviors are also independently and significantly associated with a higher prevalence of overweight including obesity: absence (OR 1.43, 0.91-2.23) or rare (OR 1.57, 1.23-2.01) breakfast intake (p importance to carry out multifaceted educational actions among adolescents, by promoting physical activity and healthy food choices in order to prevent overweight and promote healthy lifestyle behaviors. PMID:22773296

  2. 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.

  3. Knygos viršelio tekstas ir anotacija paskutiniame knygos puslapyje gretinamuoju teksto žanrų analizės požiūriu

    OpenAIRE

    Kontutytė, Eglė

    2012-01-01

    Teksto žanrų tyrimai – vienas iš svarbiausių teksto lingvistikos uždavinių. Naujausiu teksto lingvistikos požiūriu žanrus tirti ir įvertinti galima tik kitų teksto žanrų apsuptyje. Knygos atveju galima kalbėti apie su knyga susijusių teksto žanrų „šeimą“, apie keletą skirtingo turinio tekstų, atliekančių panašią funkciją. Tyrimo objektu pasirinkti kalbotyros knygų viršelio tekstai ir anotacijos paskutiniame puslapyje. Tyrimo tikslas, remiantis visuminiais žanrų analizės modeliais, nustatyti š...

  4. 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.

  5. 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

  6. 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

  7. 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...

  8. 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.

  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. Neutron-diffraction reinvestigation of NiCO3

    Science.gov (United States)

    Plumier, R.; Sougi, M.; Saint-James, R.

    1983-10-01

    Detailed powder neutron-diffraction experiments performed on NiCO3 show that at low temperature this carbonate is an antiferromagnet with an antiferromagnetic direction perpendicular to the trigonal axis and not at an angle 63° to this axis as has been previously reported. The oxygen parameter is found to be u=0.2813+/-0.0005, the largest found in the series of carbonates of the iron family. A careful examination of the magnetic reflection intensities indicates in NiCO3 a form-factor expansion and a magnetic-moment reduction leading to the same covalency parameter as that previously reported in NiO and KNiF3. Comparison with the isomorphous compounds MnCO3 and CoCO3 indicates in NiCO3 an increase of the superexchange interactions, both isotropic and anisotropic, a decrease of the spin-exchange polarization through the (CO3)2- radicals, and a substantial reduction of the covalency parameter.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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。

  16. 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.

  17. Formation of carrageenan-CaCO3 bioactive membranes.

    Science.gov (United States)

    Nogueira, Lucas F B; Maniglia, Bianca C; Pereira, Lourivaldo S; Tapia-Blácido, Delia R; Ramos, Ana P

    2016-01-01

    The high biocompatibility and resorbability of polymeric membranes have encouraged their use to manufacture medical devices. Here, we report on the preparation of membranes consisting of carrageenan, a naturally occurring sulfated polysaccharide that forms helical structures in the presence of calcium ions. We incorporated CaCO3 particles into the membranes to enhance their bioactivity and mechanical properties. Infrared spectroscopy and X-ray diffraction data confirmed CaCO3 incorporation into the polymeric matrix. We tested the bioactivity of the samples by immersing them in a solution that mimics the ionic composition and pH of the human body fluid. The hybrid membranes generated hydroxyapatite, as attested by X-ray diffraction data. Scanning electron and atomic force microscopies aided investigation of membrane topography before and after CaCO3 deposition. The wettability and surface free energy, evaluated by contact angle measures, increased in the presence of CaCO3 particles. These parameters are important for membrane implantation in the body. Moreover, membrane stiffness was up to 110% higher in the presence of the inorganic particles, as revealed by Young's modulus. PMID:26478280

  18. 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.

  19. Design and Syntheses of Three Novel Carbonate Halides: Cs3 Pb2 (CO3 )3 I, KBa2 (CO3 )2 F, and RbBa2 (CO3 )2 F.

    Science.gov (United States)

    Liu, Lili; Yang, Yun; Dong, Xiaoyu; Zhang, Bingbing; Wang, Ying; Yang, Zhihua; Pan, Shilie

    2016-02-01

    Three new carbonate halides, Cs3 Pb2 (CO3 )3 I, KBa2 (CO3 )2 F and RbBa2 (CO3 )2 F have been synthesized with hydrothermal and solid-state methods. Cs3 Pb2 (CO3 )3 I is the first product in the lead carbonate iodides family; KBa2 (CO3 )2 F and RbBa2 (CO3 )2 F are the first two centrosymmetric compounds found in the alkaline-alkaline earth carbonate fluorides family. Cs3 Pb2 (CO3 )3 I crystallizes in a centrosymmetric space group C2/m, and exhibits a two- dimensional layered structure which is formed by [Cs4 Pb4 (CO3 )6 I2 ]∞ double-layers consisting of [Pb2 (CO3 )3 I]∞ single-layers bridged by the Cs atoms. KBa2 (CO3 )2 F and RbBa2 (CO3 )2 F, which are isostructural, crystallize in a trigonal crystal system with a centric space group of R3‾ featuring a honeycomb-like framework. First principle calculations indicate that Cs3 Pb2 (CO3 )3 I has a moderate birefringence and explain the difference between the band gaps of the title compounds from electron structures. The effects of cations and halogens on the structures and properties of the title compounds are also discussed. PMID:26822173

  20. Ce2Co3Ge5: a new U2Co3Si5 - type valance fluctuating compound

    International Nuclear Information System (INIS)

    Poly crystalline sample of Ce2Co3Ge5 have been prepared by arc melting and consequently annealing at 1100 deg C. Rietveld refinement of XRD shows that it crystallize in the orthorhombic U2Co3Si5 structure (space group Ibam) with crystal parameters a= 9.802A, b= 11.777A and c= 5.941A and unit cell volume V= 684.8 A3 The unit cell volume of Ce2Co3Ge5 is seen clearly to deviate from that expected on the basis of lanthanide contraction. From susceptibility measurement, effective magnetic moment of this compound μeff = 0.95 μB which is lower than magnetic moment free for Ce3+ ions (2.54 μB) but higher than that of non-magnetic Ce4+ state (0 μB). All these results clearly indicated Ce2Co3Ge5 to be a mixed valance compound. (author)

  1. 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.

  2. Observation of superficial antiferromagnetism in Co3O4 polycrystals

    Science.gov (United States)

    von Dreifus, Driele; Chaves Pereira, Ernesto; Aparecido de Oliveira, Adilson Jesus

    2015-11-01

    We report on a systematic study about the magnetic properties of Co3O4 polycrystals with large size distribution (100-1200 nm) and the crystallite size of 68(4) nm on average. An antiferromagnetic transition at T N = 32 K, extensively reported in the literature for Co3O4, was observed. Furthermore, another transition at T t = 14 K, which is suppressed for H ≥ 35 kOe, was also identified. An increase in the magnetic susceptibility, as well as irreversibility between zero field cooled and field cooled data below T t were observed. The non-detection of a coercive field below T t, and the fact that T t and T N are independent from the driven frequencies in ac magnetic measurements as a function of temperature, confirm that both peaks are associated to antiferromagnetic transitions.

  3. 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.

  4. 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.

  5. 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.

  6. 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 ...

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

    OpenAIRE

    Krastinova, Evguenia; Seng, Remonie; Yeni, Patrick; Viard, Jean-Paul; Vittecoq, Daniel; Lascoux-Combe, Caroline; Fourn, Erwan; Pahlavan, Golriz; Delfraissy, Jean François; Goujard, Cécile; Meyer, Laurence

    2013-01-01

    OBJECTIVE: Guidelines for initiating HIV treatment are regularly revised. We explored how physicians in France have applied these evolving guidelines for ART initiation over the last decade in two different situations: chronic (CHI) and primary HIV-1 infection (PHI), since specific recommendations for PHI are also provided in France. METHODS: Data came from the ANRS PRIMO (1267 patients enrolled during PHI in 1996-2010) and COPANA (800 subjects enrolled at HIV diagnosis in 2004-2008) cohorts....

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

    OpenAIRE

    Juan Berenguer; Ferdinand Wit; Jansson, Per O; Christine Schwimmer; Kowalska, Justyna D; Juliette Saillard; Alpha Diallo; Pozniak, Anton L.; François Raffi; Jesper Grarup

    2014-01-01

    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 ch...

  9. 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.

  10. APEX CO(3-2) observations of NGC6822

    OpenAIRE

    De Rijcke, S.; Buyle, P.; Cannon, J.; Walter, F.; Lundgren, A.; Michielsen, D.; Dejonghe, H.

    2006-01-01

    We observed the CO(3-2) emission of the emission-line regions HubbleI, HubbleV, HubbleX, Holmberg 18, and the stellar emission-line object S28 in NGC6822 with the ESO Atacama Pathfinder Experiment (APEX) 12m telescope as part of its science verification. The very low system temperature of 130-180K enabled us to achieve detections in 4 single pointings and in a high spatial resolution 70''x70'' map of HubbleV. We compare the spectra with HI observations, obtained with the Australia Telescope C...

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  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. 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...

  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. 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%.

  20. 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)

  1. Investigation of interaction processes in SrCO3-VOsub(1,5) and BaCO3-VOsub(1,5) systems

    International Nuclear Information System (INIS)

    Interaction of sesquioxide of vanadium with strontium and barium carbonates is of redox character. Orthovanadate and carbon oxide are formed at the initial stage of the reaction. Therefore, it seems impossible to obtain stoichiometric vanadites MV2O4 in the systems SrCo3(BaCO3)-VOsub(1.5)

  2. 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.

  3. Solubility of Np(V) in K-Cl-CO3 and Na-K-Cl-CO3 solutions to high concentrations: measurements and thermodynamic model predictions

    International Nuclear Information System (INIS)

    The solubility of Np(V) in K-Cl-CO3 and Na-K-Cl-CO3 solutions was measured to confirm a published thermodynamic model for Np(V) solubility and solubility-controlling solid phases. Undersaturation experiments starting with NpO2OH(am), KNpO2CO3(s), or Na3NpO2(CO3)2(s) were conducted in KCl + K2CO3 and NaCl + KCl + Na2CO3 solutions to high electrolyte concentrations. Steady-state dissolved Np(V) concentrations were obtained within 180 days, at which time the final solid phases were characterized by X-ray diffraction techniques. The thermodynamic model and data base, based on the Pitzer ion interaction formalism for activity coefficients, has been parameterized in the NaCl, NaClO4, NaCl-CO2(g), NaClO4-CO2(g), Na2CO3, and K2CO3 systems but has not been parameterized using data from K-Cl-CO3 and Na-K-Cl-CO3 solutions. Predictions from the thermodynamic model match measured Np(V) solubilities in K-Cl-CO3 solutions to within 0.3 log units, confirming recent parameter values. Np(V) solubilities in Na-K-Cl-CO3 solutions agree within 0.5 log units when KNpO2CO3(s) was the equilibrium solid phase. A deviation of up to 0.8 log units resulted when Na3NpO2(CO3)2(s) was the equilibrium solid phase. Additionally, the data base provides satisfactory predictions of oversaturation solubility experiments in three complex synthetic brines. This work demonstrates that thermodynamic models can provide reliable predictions of Np(V) solubility in concentrated groundwaters such as may exist in the near- and far-field environments of nuclear waste repositories located in salt beds. (orig.)

  4. 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.

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

    Science.gov (United States)

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

    2014-10-01

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

  6. 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

  7. Enhancement of the visible light activity and stability of Ag2CO3 by formation of AgI/Ag2CO3 heterojunction

    Science.gov (United States)

    Yu, Changlin; Wei, Longfu; Zhou, Wanqin; Chen, Jianchai; Fan, Qizhe; Liu, Hong

    2014-11-01

    An insurmountable problem for silver-based semiconductor photocatalysts is their poor stability. Here, at room temperature, AgI with different concentrations (5%, 10%, 20% and 30%) were coupled into Ag2CO3, producing a series of novel AgI/Ag2CO3 composite photocatalysts. The effects of AgI addition on the Ag2CO3 catalyst for photocatalytic degradation of methyl orange (MO) under visible light irradiation have been investigated. Some physicochemical technologies like N2 physical adsorption/desorption, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectroscopy (UV-vis DRS) were applied to characterize these products. Results show that the photocatalytic degradation activity of AgI/Ag2CO3 photocatalyst is much higher than that of pure AgI and Ag2CO3. With the optimal content of AgI (20 wt%), the AgI/Ag2CO3 exhibits the highest photocatalytic degradation efficiency. Its first order reaction rate constant (0.54 h-1) is 20 times of that of AgI (0.026 h-1) and 3.6 times of that of Ag2CO3 (0.15 h-1). The characterizations and theory calculation show that AgI and Ag2CO3 have suitably matched band gap structures. The formation of AgI/Ag2CO3 heterojunction with intimate interface could effectively increase the separation efficiency of the e-/h+ pairs and promote the production of •OH and O2•- radicals, which brings about the fast degradation rate of the dye and an increase in photocatalytic stability.

  8. 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

  9. 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.

  10. A facile one-pot synthesis of higher yield porphyrin functionalized Co3O4 nanoparticles

    International Nuclear Information System (INIS)

    Graphical abstract: Porphyrins functionalized Co3O4 nanoparticles were prepared firstly via a facile one-step method. The high yield of prophyrin functionalized Co3O4 nanoparticles is more than 90%. - Highlights: • Por-Co3O4 NPs were first prepared via a facile one-pot hydrothermal method. • The yield of porphyrin-Co3O4 nanoparticles is more than 90%. • FT-IR reveals the coordination interaction between porphyin molecules and Co3O4. • Ethanol and the appropriate temperature are necessary in this experiment. - Abstract: Porphyrin functionalized Co3O4 nanoparticles were first prepared via a facile one-pot hydrothermal method. The functionalized nanoparticles were characterized by X-ray diffraction and transmission electron microscopy. Fourier transform infrared spectra revealed the coordination interaction between porphyrin molecules and Co3O4. The high yield of prophyrin functionalized Co3O4 nanoparticles is more than 90%. The phase, morphology and size of as-prepared nanoparticles were dramatically affected by the ratio of solvents, temperature and porphyrins with different substituents, respectively. Experimental results revealed that ethanol and the appropriate temperature were necessary for the formation of single-phase Co3O4. Furthermore, a probable growth mechanism of the formation of porphyrin functionalized Co3O4 nanoparticles was proposed

  11. 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.

  12. 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.

  13. Generation of Co3O4 microparticles by solution combustion method and its Zn–Co3O4 composite thin films for corrosion protection

    International Nuclear Information System (INIS)

    Graphical abstract: The pseudo-cubic cobalt oxide microparticles have been successfully synthesized by a solution combustion method using Co(NO3)2·6H2O (oxidizer) and dextrose (sugar; fuel). The as-synthesized Co3O4 microparticles are crystalline and Rietveld refinement of calcined samples exhibited cubic structure with space group of Fm3m (No. 227). The generated Co3O4 microparticles were used to fabricate Zn–Co3O4 composite thin films for corrosion protection. Highlights: ► Synthesis of pseudo-cubic Co3O4 microparticles by solution combustion method. ► As-prepared Co3O4 compounds are calcined and structurally characterized. ► Prepared Co3O4 are utilized for the fabrication of Zn–Co3O4 composite thin films. - Abstract: Microcrystalline cobalt oxide (Co3O4) powder was successfully synthesized by a simple, fast, economical and eco-friendly solution-combustion method. The as-synthesized powder was calcined for an hour at temperatures ranging from 100 to 900 °C. The crystallite size, morphology, and chemical state of synthesized powders were characterized by powder XRD, TG-DTA, XPS, SEM/EDAX, TEM and FT-IR spectral methods. The as-synthesized Co3O4 powder was single-crystalline and Rietveld refinement of calcined samples exhibited cubic structure with space group of Fm3m (No. 227). The effect of calcination temperature on crystallite size and morphology was assessed. Scanning electron micrographs show a uniform, randomly oriented pseudo-cubic particle with porous like morphology and EDAX measurement showed its chemical composition. Thermal behavior of as-synthesized compound was examined. The TEM result revealed that, the particles are pseudo-cubic in nature with diameter of 0.2–0.6 μm and a length of 0.9–1.2 μm. The crystallite size increased with increase of calcination temperature. The synthesized Co3O4 powder was used to fabricate Zn–Co3O4 composite thin films and its corrosion behavior was analyzed by anodic polarization, tafel extrapolation

  14. 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

  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. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. Dynamics of fossil fuel CO2 neutralization by marine CaCO3

    Science.gov (United States)

    Archer, David; Kheshgi, Haroon; Maier-Reimer, Ernst

    1998-06-01

    A detailed model of the ocean circulation and carbon cycle was coupled to a mechanistic model of CaCO3 diagenesis in deep sea sediments to simulate the millennium-scale response of the oceans to future fossil fuel CO2 emissions to the atmosphere and deep sea. Simulations of deep sea injection of CO2 show that CaCO3 dissolution is sensitive to passage of high-CO2 waters through the Atlantic Ocean, but CaCO3 dissolution has a negligible impact on atmospheric pCO2 or the atmospheric stabilization CO2 emission in the coming centuries. The ultimate fate of the fossil fuel CO2 will be to react with CaCO3 on the seafloor and on land. An initial CaCO3 dissolution spike reverses the net sedimentation rate in the ocean until it is attenuated by an enhanced vertical gradient of alkalinity after about 1000 years. The magnitude of the initial spike is sensitive to assumptions about the kinetics for CaCO3 dissolution, but subsequent behavior appears to be less model dependent. Neutralization by seafloor CaCO3 occurs on a timescale of 5-6 kyr, and is limited to at most 60-70% of the fossil fuel release, even if the fossil fuel release is smaller than the seafloor erodible inventory of CaCO3. Additional neutralization by terrestrial CaCO3 restores a balance between CaCO3 weathering and seafloor accumulation on a timescale of 8.5 kyr, while the deficit of seafloor CaCO3 (the lysocline) is replenished with an e-folding timescale of approximately 18 kyr. The final equilibrium with CaCO3 leaves 7-8% of the fossil fuel CO2 remaining in the atmosphere, to be neutralized by the silicate rock cycle on a time frame of hundreds of thousands of years.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. Early changes in coagulation but not inflammatory biomarkers under intermittent ART: the randomized ANRS 106 WINDOW trial

    Directory of Open Access Journals (Sweden)

    Sébastien Gallien

    2014-11-01

    Full Text Available Introduction: In the SMART trial, baseline plasma hsCRP, IL6 and D-dimer levels were strongly correlated to all-cause mortality. A case-control study has shown an increase of IL-6 and D-dimer levels after one month of antiretroviral therapy (ART interruption, which was correlated to viral load. Restarting ART was associated to a decrease in D-dimer but not IL-6 or hsCRP levels. We assessed biomarkers levels up to 96 weeks in ART-experienced adults with plasma HIV RNA levels <400 c/mL randomized in the ANRS 106 WINDOW trial to intermittent ART (IT: six cycles of eight weeks of ART interruption followed by eight weeks of ART versus continuous treatment (CT. Methods: Stored plasma for 160 participants (80 IT and 80 CT, matched by age, sex and CDC classification, were analyzed blinded for IL-6, sCD-14, hsCRP and D-dimer levels at baseline, week 8 (IT group only, week 16 and week 96. Lower levels of detection for IL-6, sCD14, hsCRP and D-Dimer were 1.5 pg/mL, 250 ng/mL, 0.03 µg/mL and 0.21 µg/mL, respectively. The primary objective was to compare changes in IL-6, hsCRP, sCD14 and D-dimer plasma levels from baseline to week 8, 16 and 96 in the IT and CT arms. Biomarkers levels were log10 transformed prior to analysis. Results: At baseline, patients were mostly men (86%, with a median age of 40 years, a CD4+ T-cell count of 768/mm3, have received a median of 4.7 years of ART and 85% had HIV RNA <50 c/mL. Proportion of patients with plasma HIV RNA levels<400 c/mL were 6% and 99%, 81% and 97%, 86% and 92% at weeks 8, 16 and 96 in the IT and CT arms, respectively. Plasma biomarkers levels are shown in the Table 1.Compared to baseline, D-dimer levels significantly increased 8 weeks after ART interruption in the IT arm (+23% fold change, 95% CI +9% to +39% but reverted to baseline levels at week 16 and remained unchanged at week 96. There was no significant change from baseline in the other biomarker levels in the IT arm. Similarly, no significant change

  8. 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

  9. 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.

  10. 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.

  11. Room Temperature Ammonia Gas Sensing Characteristics of Co3O4

    Directory of Open Access Journals (Sweden)

    P.N. Shelke

    2011-01-01

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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  13. 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.

  14. Crystal structure and magnetic properties of ultrafine nanocrystalline SmCo3 compound

    International Nuclear Information System (INIS)

    The single-phase ultrafine nanocrystalline SmCo3 compound with a high coercivity of 33 kOe and a Curie temperature of 925 K was prepared using a simple and efficient method, which took advantages of the concurrent processes of nanocrystallization and densification during spark plasma sintering. The crystal structure of the nanocrystalline SmCo3 compound was constructed. As compared with the conventional microcrystalline SmCo3 compound, a large axial ratio c/a = 4.920 and an expansion of the unit cell volume of 2.97% were obtained in the lattice structure of the nanocrystalline SmCo3. The relationship between the magnetic properties and the nanocrystalline structure was analyzed. A specific magnetic transition from the weak ferromagnetic to the strong ferromagnetic state was discovered in the nanocrystalline SmCo3 compound, which was considered to be related to the large anisotropic strain in the crystal lattice.

  15. 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.

  16. Co3O4 nanowires as high capacity anode materials for lithium ion batteries

    International Nuclear Information System (INIS)

    Highlights: ► The Co3O4 nanowires are synthesized from decomposition of CoC2O4·2H2O nanowires. ► The synthesis procedure shows us a facile and highly productive strategy. ► The Co3O4 nanowires are suitable as a promising anode material for LIBs. ► High capacity and good cycling stability are achieved for the Co3O4 nanowires. - Abstract: Co3O4 nanowires were synthesized from the decomposition of CoC2O4·2H2O nanowires which were obtained through a polyvinyl alcohol (PVA)-assisted solution-based precipitation process. And the formation mechanism of CoC2O4·2H2O nanowires was discussed. The Co3O4 nanowires had diameters in the range of 30–60 nm and lengths of several micrometers, inheriting the morphology of the CoC2O4·2H2O nanowires. The Co3O4 nanowires as an anode material in lithium-ion batteries exhibited a stable specific discharge/charge capacity of 611 mAh/g and 598 mAh/g after fifty cycles at a current density of 0.11 A/g, which were much higher than that of commercial Co3O4 nanoparticles. In addition, the charge capacity of the as-synthesized Co3O4 nanowires was more than two times higher than that of the commercial Co3O4 nanoparticles at a current density of 1.1 A/g. These results indicate that the as-prepared Co3O4 nanowires have potential to be a promising candidate as high capacity anode material in the next generation lithium-ion batteries.

  17. 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.

  18. 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.

  19. 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. PMID:26356113

  20. 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.

  1. 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

  2. [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.

  3. 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...

  4. 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...

  5. 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.

  6. 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.

  7. 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.

  8. Thermal behavior of SrSO4-SrCO3 and SrSO4-SrCO3-Al2O3 mixtures

    International Nuclear Information System (INIS)

    The high temperature behavior of SrSO4, SrCO3 and Al2O3 mixtures was studied. A mixture of 1:1 mole of SrSO4 and mechanically activated SrCO3 was mixed and characterized using thermal gravimetric analysis. Some samples were uniaxially pressed and sintered at 1100, 1200 and 1300 deg. C for 8 h and then analyzed using X-ray diffraction and scanning electron microscopy. Additionally, a mixture of SrSO4:SrCO3:Al2O3 was uniaxially pressed and sintered at 1500 deg. C. The decomposition temperature of SrCO3 was decreased 18 deg. by milling for 180 min. Samples sintered at 1300 deg. C showed a microstructure free of porosity. X-ray diffraction analysis showed the presence of SrO and SrSO4 after sintering at 1100, 1200 and 1300 deg. C. The mixture containing alumina showed the formation of a strontium aluminum oxide sulfate compound in addition to strontium aluminate

  9. 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。

  10. 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.

  11. 'Scorpion-like' dithiocarbamato-carboxylate ligands for linking M(CO)3+ (M = Tc, Re)

    International Nuclear Information System (INIS)

    Complexation of M(CO)3+ (M = Tc, Re) with dithiocarbamato-carboxylate ligands was studied. It was found that the dithiocarbamate chelation unit has rather high affinity to M(CO)3+ species and the resulting complexes are extremely stable in a wide pH range. The complex M(CO)3[S2CN(CH2COO)2] is monomeric in solution (ESI MS) and dimeric in the crystal phase (single-crystal XRD). The 'scorpion-like' dithiocarbamato-carboxylate ligands were prepared; it was shown that C5 chain is long enough to reach back to the free coordination vacancy in M(CO)3+ core and to block it. (author)

  12. Structural, electrical and optical properties of Co3O4 nanoparticles

    Science.gov (United States)

    Makhlouf, Salah A.; Bakr, Zinab H.; Aly, Kamal I.; Moustafa, M. S.

    2013-12-01

    Co3O4 nanoparticles were prepared by chemical precipitation followed by heat treatment at different temperatures. The structure and morphology of Co3O4 nanoparticles were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Transmission electron microscopy and the N2 adsorption-desorption techniques. The results indicate the formation of a single crystalline Co3O4 phase with a high surface area, mesoporous structure and particles size that depends on the calcination temperature. DC electrical conductivity was investigated in the temperature range 160-470 K. Variation of the electrical conductivity with temperature reveals double-valued activation energy, and the data was discussed in view of the structural and morphological properties. The temperature dependence of the AC conductivity and dielectric constant was also investigated in the same temperature range. In addition, analysis of the optical properties indicates a red shift of the absorption peaks relative to bulk Co3O4.

  13. 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.

  14. Synthesis of Co3S4 Nanosheets and Their Superior Supercapacitor Property

    Science.gov (United States)

    Xu, Bo; Pan, Lu; Zhu, Qiyong

    2016-03-01

    Sheet-like Co3S4 nanomaterial with high purity was synthesized via a facile and easily controlled one-step hydrothermal route. The structure and morphology of the as-synthesized sample was characterized by x-ray diffraction, transmission electron microscopy, and field emission scanning electron microscopy, respectively. The Co3S4 nanosheets with a mean size of 10 nm or so were used as electrode material and the supercapacitor property was determined. The results show that the specific capacitance of the Co3S4 nanosheets reaches 1037 F/g at 1 A/g. After 3000 charge-discharge recycles, the remained specific capacitance of the supercapacitor is 978 F/g, which is 94.3% of its initial value. The experiments indicate that the Co3S4 supercapacitor possesses high specific capacitance and excellent cyclic stability, which suggests its potential application in supercapacitor.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. Three-dimensional porous graphene-Co3O4 nanocomposites for high performance photocatalysts

    Science.gov (United States)

    Bin, Zeng; Hui, Long

    2015-12-01

    Novel three-dimensional porous graphene-Co3O4 nanocomposites were synthesized by freeze-drying methods. Scanning and transmission electron microscopy revealed that the graphene formed a three-dimensional porous structure with Co3O4 nanoparticles decorated surfaces. The as-obtained product showed high photocatalytic efficiency and could be easily separated from the reaction medium by magnetic decantation. This nanocomposite may be expected to have potential in water purification applications.

  20. 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...

  1. Preparation, electronic structure, and photocatalytic properties of Bi2O2CO3 nanosheet

    International Nuclear Information System (INIS)

    Bi2O2CO3 nanosheet with a thickness of less than 20 nm was synthesized via hydrothermal and solvothermal process. The properties of the as-prepared nanosheet were characterized by X-ray diffraction, scanning electron microscopy, and diffuse reflectance spectra. The electronic structure was investigated using first-principle calculations. Application of the as-prepared Bi2O2CO3 nanosheet in photocatalysis was also studied.

  2. 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.

  3. Synthesis of Co/Co3O4 nanocomposite particles relevant to magnetic field processing.

    Science.gov (United States)

    Srivastava, A K; Madhavi, S; Menon, M; Ramanujan, R V

    2010-10-01

    Co/Co3O4 nanocomposite particles of various morphologies were synthesized by the reverse micelle technique. Equiaxed, rod and faceted crystals with rectangular, pentagonal and hexagonal cross sections were observed. Annealing resulted in the formation of a composite of cobalt oxide (Co3O4) and fcc 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. PMID:21137765

  4. 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.

  5. 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...

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

    Science.gov (United States)

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

    2015-02-01

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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. Co3O4/ZnO nanocomposites for gas-sensing applications

    International Nuclear Information System (INIS)

    Highlights: ► By a facile wet-chemistry route Co3O4/ZnO nanocomposites were successfully prepared. ► The ZnO is loaded on the surface of Co3O4 nanoparticles with compact hetero-interface. ► The obtained nanocomposites exhibit enhanced gas sensing properties with good stability and high sensing response. ► The excellent gas sensing properties and the easily scaled-up preparation route make the prepared nanocomposites promising for real application. - Abstract: Co3O4/ZnO nanocomposites were prepared by an easy wet-chemistry route without any organic additive or surfactant used. The nanocomposites were systematically characterized by X-ray powder diffraction, scanning electron microscopy, (high-resolution) transmission electron microscopy, selected area electron diffraction, and energy-dispersive X-ray spectroscopy. The results show that ZnO is loaded on the surface of Co3O4 nanoparticles with a compact and clean hetero-interface. The obtained nanocomposites were tested for gas-sensing applications with ethanol and formaldehyde as model gases. It was revealed that the nanocomposites exhibit enhanced gas-sensing performance such as high stability and high sensing response. The sensing responses to 100 ppm ethanol or formaldehyde (46 to ethanol and 20 to formaldehyde) are much higher than those of pristine Co3O4 nanoparticles (6.2 to ethanol and 4.4 to formaldehyde), commercial Co3O4 powder (1.6 to ethanol and 1.5 to formaldehyde), and pure ZnO sample (7.5 to ethanol and 4.1 to formaldehyde). These results suggest that the integration of Co3O4 with ZnO is a promising route to the development of effective sensing materials. The excellent gas-sensing properties and the easily up-scalable preparation route make the prepared nanocomposites be promising for real applications.

  15. 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.

  16. 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.

  17. 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.

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

    Science.gov (United States)

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

    2015-08-01

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

  19. 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)

  20. 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

  1. Characterization of corn starch films reinforced with CaCO3 nanoparticles.

    Directory of Open Access Journals (Sweden)

    Qingjie Sun

    Full Text Available The characterization of corn starch (CS films impregnated with CaCO3 nanoparticles was investigated. Criteria such as morphology, crystallinity, water vapor permeability (WVP, opacity, and mechanical properties were the focus of the investigation. It was found that the CaCO3 contents had significant effects on the tensile properties of the nanocomposite films. The addition of CaCO3 nanoparticles to the CS films significantly increased tensile strength from 1.40 to 2.24 MPa, elongation from 79.21 to 118.98%, and Young's modulus from 1.82 to 2.41 MPa. The incorporation of CaCO3 nanoparticles increased the opacity of films, lowered the degree of WVP and film solubility value compared to those of the CS films. The results of scanning electron microscopy (SEM showed that with the increase of CaCO3 nanoparticles content in starch films, the roughness of the films increased, and pores or cavities were found on the surface of the films, while small cracks were observed in the structures of the fractured surfaces. X-ray diffraction showed that the addition of nanoparticles increased the peaks in the intensity of films.

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

    International Nuclear Information System (INIS)

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

  3. 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.

  4. 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.

  5. The structural, electronic and dynamic properties of the L12- type Co3Ti alloy

    International Nuclear Information System (INIS)

    The structural, electronic and dynamic properties of the cubic Co3Ti alloy in L12 structure have been investigated using a pseudopotential plane wave (PP-PW) method within the generalized gradient approximation proposed by Perdew–Burke–Ernzerhof (GGA-PBE). The structural properties, including the lattice constant, the bulk modulus and its pressure derivative agree reasonably with the previous results. The density of state (DOS), projected density of state (PDOS) and electronic band structure are also reported. The DOS shows that Co3Ti alloy has a metallic character since the energy bands cross the Fermi level. The density of states at Fermi level mainly comes from the Co-3d states. Phonon dispersion curves and their corresponding total densities of states were obtained using a linear response in the framework of the density functional perturbation theory. All computed phonon frequencies are no imaginer and thus, Co3Ti alloy is dynamically stable. The zone center phonon modes have been founded to be 9.307, 9.626 and 13.891 THz for Co3Ti

  6. Epitaxy of polar semiconductor Co3O4 (110): Growth, structure, and characterization

    International Nuclear Information System (INIS)

    The (110) plane of Co3O4 spinel exhibits significantly higher rates of carbon monoxide conversion due to the presence of active Co3+ species at the surface. However, experimental studies of Co3O4 (110) surfaces and interfaces have been limited by the difficulties in growing high-quality films. We report thin (10–250 Å) Co3O4 films grown by molecular beam epitaxy in the polar (110) direction on MgAl2O4 substrates. Reflection high-energy electron diffraction, atomic force microscopy, x-ray diffraction, and transmission electron microscopy measurements attest to the high quality of the as-grown films. Furthermore, we investigate the electronic structure of this material by core level and valence band x-ray photoelectron spectroscopy, and first-principles density functional theory calculations. Ellipsometry reveals a direct band gap of 0.75 eV and other interband transitions at higher energies. A valence band offset of 3.2 eV is measured for the Co3O4/MgAl2O4 heterostructure. Magnetic measurements show the signature of antiferromagnetic ordering at 49 K. FTIR ellipsometry finds three infrared-active phonons between 300 and 700 cm−1.

  7. First principles study of structural stability and site preference in Co3 (W,X

    Directory of Open Access Journals (Sweden)

    Joshi Sri Raghunath

    2014-01-01

    Full Text Available Since the discovery [1] of γ′ precipitate (L12 – Co3(Al, W in the Co-Al-W ternary system, there has been an increased interest in Co-based superalloys. Since these alloys have two phase microstructures (γ + γ′ similar to Ni-based superalloys [2], they are viable candidates in high temperature applications, particularly in land-based turbines. The role of alloying on stability of the γ′ phase has been an active area of research. In this study, electronic structure calculations were done to probe the effect of alloying in Co3W with L12 structure. Compositions of type Co3(W,X, (where X/Y = Mn, Fe, Ni, Pt, Cr , Al, Si, V, W, Ta, Ti, Nb, Hf, Zr and Mo were studied. Effect of alloying on equilibrium lattice parameters and ground state energies was used to calculate Vegard's coefficients and site preference related data. The effect of alloying on the stability of the L12 structure vis a vis other geometrically close packed ordered structures was also studied for a range of Co3X compounds. Results suggest that the penchant of element for the W sublattice can be predicted by comparing heats of formation of Co3X in different structures.

  8. Multifunctional Co3S4/graphene composites for lithium ion batteries and oxygen reduction reaction.

    Science.gov (United States)

    Mahmood, Nasir; Zhang, Chenzhen; Jiang, Jie; Liu, Fei; Hou, Yanglong

    2013-04-15

    Cobalt sulfide is a good candidate for both lithium ion batteries (LIBs) and cathodic oxygen reduction reaction (ORR), but low conductivity, poor cyclability, capacity fading, and structural changes hinder its applications. The incorporation of graphene into Co3S4 makes it a promising electrode by providing better electrochemical coupling, enhanced conductivity, fast mobility of ions and electrons, and a stabilized structure due to its elastic nature. With the objective of achieving high-performance composites, herein we report a facile hydrothermal process for growing Co3S4 nanotubes (NTs) on graphene (G) sheets. Electrochemical impedance spectroscopy (EIS) verified that graphene dramatically increases the conductivity of the composites to almost twice that of pristine Co3S4. Electrochemical measurements indicated that the as-synthesized Co3S4/G composites exhibit good cyclic stability and a high discharge capacity of 720 mA h g(-1) up to 100 cycles with 99.9% coulombic efficiency. Furthermore, the composites react with dissolved oxygen in the ORR by four- and two-electron mechanisms in both acidic and basic media with an onset potential close to that of commercial Pt/C. The stability of the composites is much higher than that of Pt/C, and exhibit high methanol tolerance. Thus, these properties endorse Co3 S4 /G composites as auspicious candidates for both LIBs and ORR. PMID:23447515

  9. Ultrathin Co3 O4 Layers Realizing Optimized CO2 Electroreduction to Formate.

    Science.gov (United States)

    Gao, Shan; Jiao, Xingchen; Sun, Zhongti; Zhang, Wenhua; Sun, Yongfu; Wang, Chengming; Hu, Qitao; Zu, Xiaolong; Yang, Fan; Yang, Shuyang; Liang, Liang; Wu, Ju; Xie, Yi

    2016-01-11

    Electroreduction of CO2 into hydrocarbons could contribute to alleviating energy crisis and global warming. However, conventional electrocatalysts usually suffer from low energetic efficiency and poor durability. Herein, atomic layers for transition-metal oxides are proposed to address these problems through offering an ultralarge fraction of active sites, high electronic conductivity, and superior structural stability. As a prototype, 1.72 and 3.51 nm thick Co3 O4 layers were synthesized through a fast-heating strategy. The atomic thickness endowed Co3 O4 with abundant active sites, ensuring a large CO2 adsorption amount. The increased and more dispersed charge density near Fermi level allowed for enhanced electronic conductivity. The 1.72 nm thick Co3 O4 layers showed over 1.5 and 20 times higher electrocatalytic activity than 3.51 nm thick Co3 O4 layers and bulk counterpart, respectively. Also, 1.72 nm thick Co3 O4 layers showed formate Faradaic efficiency of over 60 % in 20 h. PMID:26783062

  10. Pulsed laser deposition of Co3O4 nanocatalysts for dye degradation and CO oxidation

    International Nuclear Information System (INIS)

    Co3O4 nanoparticles (NPs) assembled coatings were synthesized using pulsed laser deposition (PLD) by taking advantage of phase explosion process. The coatings were prepared at substrate temperature of 150 °C by using three different laser fluences (3, 5, and 7 J/cm2) in order to tune the size of NPs. Structural property and surface morphology of NPs were investigated by Raman spectroscopy and electron microscopy respectively. The catalytic activity of these Co3O4 NPs coatings was tested for dye degradation as well as for CO oxidation. Co3O4 coating (3 J/cm2) was able to completely degrade Methylene blue dye with significantly high rate, via photo Fenton reaction under visible light irradiation, as compared to Co3O4 powder catalyst mainly owing to the size and nanocrystalline nature of NPs on the catalyst surface. Coating synthesized at low laser fluence (3 J/cm2) showed best catalytic activity. This particular coating also showed above 90% conversion efficiency of CO to CO2 at 250 °C with very high specific rate. The special features of NPs, such as narrow size distribution, small average size (5–20 nm), perfect spherical shape, low degree of agglomeration, and nanocrystalline phase, are the main factors responsible for the enhanced catalytic activity of the PLD produced Co3O4 NPs assembled coating.

  11. Donut-shaped Co3O4 nanoflakes grown on nickel foam with enhanced supercapacitive performances

    Science.gov (United States)

    Han, Zhicheng; Zheng, Xin; Yao, Shunyu; Xiao, Huanhao; Qu, Fengyu; Wu, Xiang

    2016-03-01

    Donut-shaped Co3O4 nanoflakes grown on nickel foam were successfully fabricated by a simple one-pot hydrothermal approach. The prepared products were functionalized as the supercapacitors electrodes. Electrochemical performance of the as-prepared products demonstrated high specific capacitance (518 mF cm-2) and excellent cycling stability (∼25% loss) after 6000 repetitive cycles at a charge-discharge current density of 1 mA cm-2. The superior electrochemical performance may be ascribed into two reasons: one is the unique spatial structures which possess many active sites and provide enhanced combination between the electrode and nickel foam to support fast ion and electron transfer, the other is that donut-shaped Co3O4 nanoflakes electrodes show relatively lower resistances. It is expected that the as-obtained donut-shaped Co3O4 nanoflakes could have potential applications in portable electronics and electrical vehicles.

  12. 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)

  13. A parametric study of CaCO3 scaling in AISI 316 stainless steel tubes

    Science.gov (United States)

    Khan, M. Sultan; Budair, M. O.; Zubair, S. M.

    The formation of undesirable layer of deposits on the heat-transfer surface is defined as fouling. These deposits present a major problem in the operation and maintenance of heat exchangers, particularly in cooling-water systems. It has been generally observed that the deposits in such systems consist mainly of calcium carbonate (CaCO3), which has inverse solubility characteristics. An experimental study was carried out to determine the effect of tube surface temperature, Reynolds number, tube diameter and salt concentration on the growth of CaCO3 scale. In this paper, effects of some of these parameters on fouling growth are discussed. The effect of CaCO3 concentration on the scale growth is compared with the ionic diffusion model presented by Hasson. The variation of the fouling thickness along the length of the heat exchanger is also illustrated. Furthermore, dimensionless parameters are introduced to present the fouling resistance data collected during the experimental study.

  14. 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

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

    DEFF Research Database (Denmark)

    Allred, Jared M.; Jia, Shuang; Bremholm, Martin; Chan, Benny C.; Cava, Robert J.

    2012-01-01

    CoSn is the prototype compound of the B35 structure, which has long been of interest due to its rarity and unusually low packing density. We report the synthesis and properties of the solid solution Co3Sn3-xGex for 0 ⩽ x ⩽ 2, in order to clarify the conditions necessary to stabilize such a phase....... By taking advantage of the chemical differences between the two crystallographically inequivalent Sn sites in the structure, we observe ordered ternary phases, nominally Co3SnGe2 and Co3Sn2Ge. The electron count and unit cell configuration remain unchanged from CoSn; these observations thus help to...

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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...

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

    DEFF Research Database (Denmark)

    Hansson, Anette Nørgaard; Friehling, Peter B.; Linderoth, Søren; Somers, Marcel A.J.

    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 sca...... of inter-diffusion between the oxide scale and the Co3O4 coating were investigated with X-ray diffraction, scanning electron microscopy and energy-dispersive spectroscopy. The results obtained are discussed in relation to a calculated Cr-Co-oxide phase diagrams....

  6. 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...

  7. 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}.

  8. 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.

  9. 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.

  10. 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.

  11. 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(glucose, Co3O4-HND could be served as an attractive non-enzyme and noble-metal-free electrocatalyst in glucose fuel cell (GFC) due to its excellent electrochemical properties, low cost and facile preparation. PMID:26918617

  12. 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...

  13. 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

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

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  15. Interferometric CO(3-2) Observations toward the Central Region of NGC 1068

    CERN Document Server

    Tsai, Mengchun; Matsushita, Satoki; Baker, Andrew J; Espada, Daniel

    2011-01-01

    We present CO(3-2) interferometric observations of the central region of the Seyfert 2 galaxy NGC 1068 using the Submillimeter Array, together with CO(1-0) data taken with the Owens Valley Radio Observatory Millimeter Array. Both the CO(3-2) and CO(1-0) emission lines are mainly distributed within ~5 arcsec of the nucleus and along the spiral arms, but the intensity distributions show differences; the CO(3-2) map peaks in the nucleus, while the CO(1-0) emission is mainly located along the spiral arms. The CO(3-2)/CO(1-0) ratio is about 3.1 in the nucleus, which is four times as large as the average line ratio in the spiral arms, suggesting that the molecular gas there must be affected by the radiation arising from the AGN. On the other hand, the line ratios in the spiral arms vary over a wide range from 0.24 to 2.34 with a average value around 0.75, which is similar to the line ratios of star-formation regions, indicating that the molecular gas is affected by star formation. Besides, we see a tight correlatio...

  16. Click chemistry for [99mTc(CO)3] labeling of Lys3-bombesin

    International Nuclear Information System (INIS)

    99mTc-HYNIC labeled Lys3-bombesin has shown specific binding to gastrin-releasing peptide receptors (GRP-r) over-expressed in cancer cells. Click chemistry offers an innovative functionalization strategy for biomolecules such as bombesin. The aim of this research was to apply a click chemistry approach for [99mTc(CO)3] labeling of Lys3-bombesin and to compare the in vitro MCF7 breast cancer cell uptake and biodistribution profile in mice with that of 99mTc-EDDA/HYNIC-Lys3-bombesin. The results suggest a higher lipophilicity for 99mTc(CO)3-triazole-Lys3-bombesin which explains its higher in vivo hepatobiliary elimination. Pancreas-to-blood ratio for 99mTc(CO)3-triazole-Lys3-bombesin was 4.46 at 3 h and both bombesin radiopharmaceuticals showed specific recognition for GRP receptors in MCF7 cancer cells. Click chemistry is a reliable approach for [99mTc(CO)3] labeling of Lys3-bombesin.

  17. 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.

  18. 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

  19. 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.

  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. 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.

  2. 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.

  3. 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)

  4. 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 ...

  5. 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

  6. 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%。

  7. 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.

  8. 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.

  9. 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 ℃.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Effects of the Na2CO3 dopant on electron injection and transport in organic light emitting devices

    International Nuclear Information System (INIS)

    Na2CO3 is used as an n-type dopant to improve the electro-optical properties of tris(8-hydroxyquinoline)aluminum (Alq3)-based organic light-emitting diodes (OLEDs). Device properties such as the turn-on voltage, maximum luminance, and device efficiency were improved as Na2CO3 was doped. The higher mobility of Na2CO3-doped samples has been derived using space-charge-limited current measurements. Photoelectron spectroscopy results show that some electrons transfer from Na2CO3 into Alq3, which moves the Fermi level close to the lowest unoccupied molecular orbital of Alq3. Therefore, both the electron-transporting ability and electron-injection efficiency were enhanced, which improves the charge carrier balance in OLEDs and leads to better device efficiency. - Highlights: ► Na2CO3-doped OLEDs have improved opto-electrical properties. ► Na2CO3-doped Alq3 layers possess an enhanced electron injection ability. ► The higher mobility of the Na2CO3-doped samples derived by the SCLC model. ► The reaction between Na2CO3 and Alq3 results in an electron transfer process. ► The Na2CO3-doping moves the Fermi level close to the LUMO of Alq3

  19. 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

  20. 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.

  1. 51V-NMR study of the Kagome staircase compound Co3V2O8

    International Nuclear Information System (INIS)

    Kagome staircase compound Co3V2O8 (S = 3/2) has a structure very similar to multiferroic compound Ni3V2Og (S = 1), but their magnetic phase diagrams differ noticeably. We present the results of the first NMR study in Co3V2O8 single crystal. From 51V-NMR spectra, the components of electric field gradient (EFG) tensor and of magnetic shifts tensor, Ki, are obtained. The temperature dependences of NMR shifts 51Ki for each main crystal axis direction are well described by a spin contributions in the paramagnetic phase. In ferromagnetic phase the zero field 51V-NMR spectrum is observed in the temperature range of 1.5-6.3 K.

  2. 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.

  3. 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

  4. Magnetization of the canted antiferromagnetic CoCO3 in Abragam-Pryce approximation

    International Nuclear Information System (INIS)

    Weiss molecular field theory was used to calculate the magnetization of the canted antiferromagnetic CoCO3 (TN=18.1K). Wave functions of magnetic doublets near Co2+ ground state in Abragam-Pryce approximation were determined. One of the crystal field variables, free Co2+ ion isotropic exchange interaction inside, and between magnetic sublatticies, and rotation angle φ, characterizing nonequivalence ion Co2+ positions, were used as parameters. From comparison with the experimental data exchange interaction anisotropy and g-factors g-bar , g-bar were obtained. At low temperatures T2+(1%)+CdCO3 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

  5. 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.

  6. 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.

  7. Co3O4/C nanocapsules with onion-like carbon shells as anode material for lithium ion batteries

    International Nuclear Information System (INIS)

    Graphical abstract: Co3O4 nanocapsules with the onion-like carbon shells were synthesized. As anode materials for lithium ion battery, the Co3O4 nanocapsules deliver an initial discharge capacity of 1467.6 mAh g−1 at 0.5 C and maintain a high reversible capacity of 1026.9 mAh g−1 after 50 cycles. -- Highlights: • Co3O4 nanocapsules with onion-like carbon shell have been synthesized. • Co3O4 nanocapsules deliver an initial discharge capacity of 1467.6 mAh g−1 at 0.5 C. • Co3O4 nanocapsules maintain a reversible capacity of 1026.9 mAh g−1 after 50 cycles. • Onion-like carbon shells can improve the electrochemical performance of Co3O4. -- Abstract: The synthesis and characterization of core/shell-type Co3O4/C nanocapsules for application as anode material in lithium ion batteries are reported in this paper. The synthesis process involves the preparation of Co/C nanocapsules using a modified arc-discharge method and the annealing of the Co/C nanocapsules at 300 °C for 2 h in air. The as-synthesized products show a spherical shape and a core/shell-type structure in which a Co3O4 nanoparticle core of diameter 10–30 nm is encapsulated by an onion-like carbon shell of thickness approximately 1 nm. The Co/C nanocapsules can be stable below 130 °C, and be oxidized above 205 °C in air. The Co3O4/C nanocapsules deliver an initial discharge capacity of 1467.6 mAh g−1 at 0.5 C and maintain a high reversible capacity of 1026.9 mAh g−1 after 50 charge–discharge cycles, much higher than the Co3O4 nanoparticles (471.5 mAh g−1). A postmortem analysis of the Co3O4 and Co3O4/C anodes subjected to prolonged cycling reveals the existence of a lower degree of surface cracking and particle breakage in the Co3O4/C anode than the Co3O4 anode. The improved electrochemical performance and structural stability in the Co3O4/C nanocapsules are attributed to the enhanced electrical conductivity and structural buffering provided by the onion-like carbon shell

  8. Heterogeneous microchemistry between CdSO4 and CaCO3 particles under humidity and liquid water

    International Nuclear Information System (INIS)

    Highlights: ► Raman analysis of chemical reactions between CdSO4 and CaCO3 particles. ► Under humid air no changes of morphology and chemical composition were observed. ► Condensation of liquid water generates an insoluble CdCO3 layer on CaCO3 surface. ► Addition of water previously equilibrated with CaCO3 generates CdCO3 and CaSO4. -- Abstract: Laboratory experiments using in situ Raman imaging combined with ex situ TOF-S-SIMS demonstrate the behavior of CdSO4·8/3H2O microparticles in contact with {101¯4} CaCO3 (calcite) surface under three different experimental conditions representative of unpolluted atmosphere. The contact of CdSO4·8/3H2O particles with CaCO3 surface in humid air (RH ∼ 40–80%) does not induce any chemical reaction. In contrast, the condensation of a water drop on CdSO4·8/3H2O/CaCO3 interface causes the free dissolution of CdSO4·8/3H2O particle in the drop. A CdSO4·8/3H2O microcrystal is reformed after gentle drying with a CdSO4·H2O coating of the CaCO3 surface. The TOF-S-SIMS image of the CaCO3 surface provides evidence of a thin layer corresponding probably to insoluble coating of CdCO3 (otavite) or CdxCa1−xCO3 solid solution at the liquid–solid interface. This layer armours the CaCO3 from further dissolution and stops the reaction. The deposition of CdSO4·8/3H2O particle in water drop previously in contact with CaCO3 for a long time generates CdCO3 small rhombohedral crystals while gentle drying provokes the crystallization of bar shape crystals of CaSO4·2H2O (gypsum). These laboratory results provide valuable chemical prediction for a possible fate of cadmium rich particles emitted in the atmosphere and thus, can contribute to realistic assessment of human exposure to Cd hazard

  9. CO2 assisted synthesis of highly dispersed Co3O4 nanoparticles on mesoporous carbon for lithium ion battery

    International Nuclear Information System (INIS)

    Graphical abstract: Co3O4 nanoparticles were uniformly dispersed onto the mesoporous carbon support (Co3O4/mC) using a facile process in CO2–expanded ethanol (CE) solution. Compared with Co3O4/mC-E synthesized in pure ethanol, the Co3O4/mC-CE exhibited better cycle performance which could be attributed to the synergistic effects between the superior structures of mesoporous C support and the highly dispersed Co3O4 nanoparticles. - Highlights: • Co3O4 nanoparticles were highly dispersed on mesoporous C in CE system. • The synthesis avoided the use of precipitants and aggregation of Co3O4 particles. • Co3O4/mC exhibited better cycle performance than the reference sample. • The synergistic effects of the mC and Co3O4 resulted in the improved performance. - Abstract: Co3O4 nanoparticles were uniformly dispersed onto the mesoporous carbon support (Co3O4/mC) using a facile process in CO2–expanded ethanol (CE) solution. During the synthesis, CO2 played the dual roles, one is to provide a simple physical expansion to evenly disperse the precursors onto the mesoporous carbon support, and the other is to offer some chemical groups such as CO32− to facilitate the complete and uniform deposition through the coordination to the metallic cations with these anions. When used as anode material for lithium ion batteries (LIBs), the Co3O4/mC synthesized in CO2-expanded ethanol solution exhibited larger surface area and better cycle performance compared with the reference sample synthesized in pure ethanol. The enhanced cycle performance could be attributed to the synergistic effects between the superior structures of mesoporous C support and the highly dispersed Co3O4 nanoparticles. More importantly, the synthesis of Co3O4/mC composite in CE solution was green and highly efficient, avoiding the use of precipitant and the aggregation of Co3O4, which would definitely enrich the strategies for the fabrication of carbon-based transition-metal oxide composites with great

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

    DEFF Research Database (Denmark)

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

    prior to glass melting, the resulting decomposition product Na2O has strong impact on the melt viscosity, phase separation and crystallisation behaviour, and also mechanical properties of the final glass. This is relatively well understood in literature. In contrast, when Na2CO3 is added as a foaming...... in the glass, making the studied cullet powder potentially suitable for producing insulation materials. Finally, we discuss these results based on supplementary x-ray diffraction and scanning electron microscopy analyses....

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

    OpenAIRE

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

    2013-01-01

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

  12. Crystallization of the CaCO3 mineral in the presence of the protein ovalbumin

    International Nuclear Information System (INIS)

    The kinetics of CaCO3 mineralization was studied by SANS in a 0.1 M aqueous CaCl2 solution in the presence of the protein ovalbumin found in chicken eggs. As the scattering from the protein and the mineral was observed within different Q regimes the evolution of the protein and mineral could be followed independently. It is observed that ovalbumin denaturates during the first 3 h and leads to a strong enhancement of mineralization

  13. Gas Permeability Properties of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)

    OpenAIRE

    Vandewijngaarden, Jens; Murariu, Marius; Dubois, Philippe; Carleer, Robert; Yperman, Jan; Adriaensens, Peter; Schreurs, Sonja; LEPOT, Nadia; Peeters, Roos; Buntinx, Mieke

    2014-01-01

    Environmental issues, such as the depletion of fossil resources and waste disposal, have instigated the development of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx), a biobased and biodegradable polymer, bacterially produced from palm oil. PHBHHx is a versatile polymer and this study aims to further characterize it for the possible application as food packaging material. In this respect, barrier properties for gases such as O2, water vapor and CO2 are of great importance. PHBHHx film...

  14. 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.

  15. High power Co3O4/ZnO p–n type piezoelectric transducer

    International Nuclear Information System (INIS)

    Enhancing the output power of piezoelectric transducer is essential in order to supply sufficient and sustainable power to wireless sensor nodes or electronic devices. In this work, a Co3O4/ZnO p–n type power piezoelectric transducer which can be operated at low frequencies has been developed by utilizing n-type semiconducting zinc oxide (ZnO) and p-type semiconducting tricobalt tetroxide (Co3O4). We utilize ZnO to be the piezoelectric transducer and build a multi-layer (Au/Co3O4/ZnO/Ti) thin film structure. The ZnO thin film with preferred orientation along the (002) plane was deposited under optimized deposition conditions on the flexible titanium (Ti) foil with thickness of 80 μm. The Co3O4/ZnO interface forms a p–n junction and increases the difference in Fermi levels between the two electrodes, resulting in the great enhancement of output power. The measured output power of the p–n type piezoelectric transducer with optimal resistance of 100 kΩ is 10.4 μW at low operating frequency of 37 Hz, which is 10.9 times of output power of ZnO piezoelectric transducers. - Highlights: • Deposited zinc oxide performed good piezoelectric coefficient. • ZnO thin film with preferred orientation along the (002) plane was deposited. • A p–n type piezoelectric transducer with enhanced output power was fabricated. • 10.9 times increment in output power was obtained. • Increase of difference in Fermi level and p–n junction formation was explained

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

    OpenAIRE

    Rashad, M.; Rüsing, M.; Berth, G.; Lischka, K.; Pawlis, A.

    2013-01-01

    Copper oxide and cobalt oxide (CuO, Co3O4) nanocrystals (NCs) have been successfully prepared in a short time using microwave irradiation without any postannealing treatment. Both kinds of nanocrystals (NCs) have been prepared using copper nitrate and cobalt nitrate as the starting materials and distilled water as the solvent. The resulted powders of nanocrystals (NCs) were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), an...

  17. 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

  18. Rambutan-like FeCO3 hollow microspheres: facile preparation and superior lithium storage performances.

    Science.gov (United States)

    Zhong, Yiren; Su, Liwei; Yang, Mei; Wei, Jinping; Zhou, Zhen

    2013-11-13

    Rambutan-like FeCO3 hollow microspheres were prepared via a facile and economic one-step hydrothermal method. The structure and morphology evolution mechanism was disclosed through time-dependent experiments. After undergoing the symmetric inside-out Ostwald ripening, the resultants formed microporous/nanoporous constructions composed of numerous one-dimensional (1D) nanofiber building blocks. Tested as anode materials of Li-ion batteries, FeCO3 hollow microspheres presented attractive electrochemical performances. The capacities were over 1000 mAh g(-1) for initial charge, ~880 mAh g(-1) after 100 cycles at 50 mA g(-1), and ~710 mAh g(-1) after 200 cycles at 200 mA g(-1). The 1D nanofiber assembly and hollow interior endow this material efficient contact with electrolyte, short Li(+) diffusion paths, and sufficient void spaces to accommodate large volume variation. The cost-efficient FeCO3 with rationally designed nanostructures is a promising anode candidate for Li-ion batteries. PMID:24066809

  19. A laboratory investigation of cyanobacterial extracellular polymeric secretions (EPS) in influencing CaCO 3 polymorphism

    Science.gov (United States)

    Kawaguchi, T.; Decho, A. W.

    2002-04-01

    Bahamian stromatolites are well-laminated structures, consisting of lithified layers alternating between unlithified layers containing fine-grained carbonate ooids. The lithified layers consist of abundant aragonite needles embedded within a matrix of extracellular polymeric secretions (EPS) by cyanobacteria, Schizothrix sp. Laboratory investigations were conducted using EPS extracted from natural stromatolites and laboratory isolates of Schizothrix sp., to chemically characterize EPS, and determine in vitro how EPS may influence CaCO 3 polymorphism. EPS mainly consisted of acidic polysaccharides and proteins. Biochemical analyses indicated that contents of uronic acids and carbohydrates in EPS from lithified layers decreased when compared with unlithified layer EPS, while the protein content remained relatively constant. CaCO 3 nucleation experiments demonstrated that EPS from the lithified layer, induced aragonite crystal formation in vitro, as confirmed by scanning electron microscopy and Fourier transform infrared (FT-IR) spectroscopy. In contrast, EPS from the unlithified layer or laboratory-cultured Schizothrix sp. induced calcite crystal formation. These laboratory results suggest the possibility that the biochemical composition, specifically small proteins, of EPS influences the resulting mineralogy of CaCO 3.

  20. 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.

  1. 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.

  2. Effect of nano BaCO3 on pyrolytic reaction of phenol-formaldehyde resin

    Science.gov (United States)

    Zhang, Xu; Ma, Qing-zhi; Zhang, Zhong-feng; Peng, Wan-xi; Zhang, Ming-long

    2009-07-01

    Phenol-formaldehyde resin is used as the most adhesive to produce waterproof plant-based composite. However, this product contains phenol and formaldehyde which can be easily released to pollute air and water. Based on the single-factor method, the effect of nano BaCO3 on situabtion of pyrolytic reaction of PF resin was studied by Py-GC/MS. There were components including carbon dioxide, D,.alpha.-tocopherol, 1,3-bis(trimethylsilyl) benzene, phenol from PF resin in 590(see manuscript) He gas. However, the 17 compounds including phenol, 2-methyl-, phenol, carbon dioxide, p-xylene, toluene, phenol, 2-ethyl-, phenol, 2,3-dimethyl-, benzene, 1,2,3-trimethyl-, etc were identified by Py-GC/MS after PF/BaCO3 composite was pyrolyzed in 590(see manuscript) He gas, and phenol and phenol derivants were found in the compounds. The result showed that nano BaCO3 could effectively delay the pyrolysis of PF resin.

  3. 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...

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

    Directory of Open Access Journals (Sweden)

    M. Rashad

    2013-01-01

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

  5. 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.

  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. 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.

  8. 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.

  9. 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.

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

    Science.gov (United States)

    Suzan-Monti, Marie; Lorente, Nicolas; Demoulin, Baptiste; Marcellin, Fabienne; Préau, Marie; Dray-Spira, Rosemary; Lert, France; Spire, Bruno

    2016-01-01

    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 did not

  12. 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

  13. 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

  14. 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

  15. New and old complex recombinant HIV-1 strains among patients with primary infection in 1996–2006 in France: The French ANRS CO06 primo cohort study

    Directory of Open Access Journals (Sweden)

    Peeters Martine

    2008-08-01

    Full Text Available Abstract Background Prevalence of HIV-1 non-B subtypes has increased overtime in patients diagnosed at the time of primary infection (PHI in France. Our objective was to characterize in detail non-B strains which could not be genetically classified into the known subtypes/Circulating Recombinant Forms (CRFs. Methods Among 744 patients enrolled in the ANRS PRIMO Cohort since 1996, 176 (23.7% were infected with HIV-1 non-B strains. The subtype/CRF could not be identified in RT for 15 (2%. The V3-V5 env region was sequenced and 3 strains (04FR-KZS, 06FR-CRN, 04FR-AUK were full-length sequenced. Phylogenetic and bootscan analyses were used to characterize the mosaic structures. Results Among V3-V5 sequences, 6 were divergent A, 2 distantly related to E or D, 2 C, 1 B and 2 remained unclassified. 04FR-KZS, isolated in a Congolese woman infected in France, clustered with 2 previously described viruses from the Democratic Republic of Congo. They represent CRF27_cpx involving A/E/G/H/J/K/U subtypes. 06FR-CRN, isolated in a homosexual Caucasian patient, was a B/C/U recombinant involving a Brazilian C strain. 04FR-AUK, isolated in a Congolese patient infected in France, was a A/K/CRF09/U recombinant clustering from gag to vif with HIV-1 MAL. Others PHI were further observed in 2006–2007 with 1 KZS and 5 CRN-like viruses, suggesting their spread in France. Conclusion This study illustrates the increasing HIV-1 diversity in France associating new (06FR-CRN and old (CRF27_cpx and "MAL-like" 04FR-AUK strains, which are rare in their region of origin but may have a possible founder effect in France. Our results strengthen the French guidelines recommending viro-epidemiological surveillance of HIV-1 diversity.

  16. Morphology-controlled synthesis of Co3O4 by one step template-free hydrothermal method

    International Nuclear Information System (INIS)

    Highlights: • Co3O4 crystals had been synthesized by one step template-free hydrothermal method. • The H2O2 plays a crucial role in morphological control of Co3O4 nanostructures. • The morphology has significant effect on the optical property of Co3O4. - Abstract: We had developed a facile synthetic route of Co3O4 crystals with different morphologies via one step template-free hydrothermal method. The phase and composition of the Co3O4 were investigated by X-ray powder diffraction and Raman spectrum. The morphology and structure of the synthesized samples were characterized by scanning electron microscopy and transmission electron microscopy. The H2O2 played a crucial role in morphological control of Co3O4 nanostructures. It only obtained Co-based precursor in the absence of H2O2. On the contrary, the Co3O4 with different morphologies including nanoparticles, nano-discs and well-defined octahedral nanostructures were synthesized in the presence of H2O2. In addition, the optical property of the obtained Co3O4 samples was investigated by UV–vis spectra

  17. 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

  18. Synthesis and characterization of spinel Co3O4 octahedra enclosed by the {1 1 1} facets

    International Nuclear Information System (INIS)

    Spinel Co3O4 octahedra synthesized by a facile redox-precipitation method were investigated for the complete oxidation of methane. XRD analysis showed that the spinel structural Co3O4 octahedra had a relatively strong (1 1 1) diffraction peak as compared with that of the irregular shaped Co3O4 nanoparticles prepared by a conventional precipitation method. The results of methane combustion test demonstrated that the Co3O4 octahedra had no catalytic activity at 300-500 deg. C, while the Co3O4 irregular nanoparticles were highly active at the same reaction conditions. HRTEM studies revealed that the Co3O4 octahedra were predominantly exposed by the low Miller-index {1 1 1} facets with the lowest surface energy, and the Co3O4 irregular nanoparticles were exposed by various crystal facets. The results exhibited that the {1 1 1} facets with the low surface energy of the Co3O4 octahedra resulted in the inert catalytic activity in the methane oxidation reaction

  19. Solubility of Li2CO3 in Na–K–Li–Cl brines from 20 to 90 °C

    International Nuclear Information System (INIS)

    Highlights: • Solubility of Li2CO3 was measured by isothermal dissolution method. • New Pitzer activity coefficient model parameters were obtained. • New chemical model was built with Aspen Plus platform. • Solubility of Li2CO3 was successfully predicted by the new model. -- Abstract: The solubility of Li2CO3 in Na–K–Li–Cl brines was measured by isothermal dissolution method within the temperature range of 20 to 90 °C. It was found the solubility of Li2CO3 in all systems investigated decreased with increasing temperature. In NaCl and KCl solutions, the solubility of Li2CO3 initially increased to a maximum value and then decreased gradually with increasing solution concentration. However, the solubility of Li2CO3 in LiCl solutions decreased with increasing LiCl concentration due to the common ion effect of added Li+. New Pitzer activity coefficient model parameters for the Li+–CO32− ion pair were obtained by using experimental solubility data of Li2CO3 in pure water, and a new chemical model was built with the aid of Aspen Plus platform. The new model was shown to successfully predict the solubility of Li2CO3 in NaCl, KCl, LiCl and mixed NaCl–KCl solutions. Moreover, the new model could aid in analyzing the separation of lithium and magnesium in brines

  20. 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

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

    Science.gov (United States)

    Mujtaba, Jawayria; Sun, Hongyu; Huang, Guoyong; Mølhave, Kristian; Liu, Yanguo; Zhao, Yanyan; Wang, Xun; Xu, Shengming; Zhu, Jing

    2016-02-01

    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.

  2. 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

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

    Science.gov (United States)

    Mujtaba, Jawayria; Sun, Hongyu; Huang, Guoyong; Mølhave, Kristian; Liu, Yanguo; Zhao, Yanyan; Wang, Xun; Xu, Shengming; Zhu, Jing

    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. PMID:26846434

  4. 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.

  5. 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%.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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. PMID:27120582

  11. 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}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.

  12. 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.

  13. 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 ...

  14. Magnetic phase diagram of the kagome staircase Co3V2O8

    International Nuclear Information System (INIS)

    Magnetization and specific heat measurements have been performed for the S=3/2 antiferromagnet on a kagome staircase, Co3V2O8 single crystal as a function of temperature and magnetic field . Using these data the phase diagram was established on the H-T plane and compared with that determined for Ni3V2O8. The both phase diagrams are described by a model of competing first and second neighbor interactions and uniaxial anisotropy with the easy-axis magnetization along the a-axis

  15. Optical, structural and morphological properties of CdS-CdCO3 films

    International Nuclear Information System (INIS)

    CdS-CdCO3 thin films were grown by chemical bath deposition. Different constant deposition temperatures were employed in the range of 20-80 grades C. From X-ray diffraction results can be observed that intensity of CdS peak is abruptly reduced when deposition temperature is decreased. By Sem images the formation and change in shape and size of crystallites can be observed as temperature is decreased. The forbidden energy band gap was 2.4-4.1 eV, determined from optical absorption. The formation of products was further confirmed with Ftir studies. (Author)

  16. 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.

  17. 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.

  18. 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。

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Enhanced rate and cycling performance of FeCO3/graphene composite for high energy Li ion battery anodes

    International Nuclear Information System (INIS)

    A FeCO3/graphene nanocomposite (FCO/GNS), in which FeCO3 nanoflakes aligned by nanowires well dispersed in graphene matrix, is successfully synthesized via a simple one-pot hydrothermal route. With the electronic conductor, buffer, dispersion and synergetic lithium storage effect of graphene, the composite exhibits significantly improved electrochemical activity and cycling stability relative to bare flower-like FeCO3 microspheres, as well as excellent rate performance and a great recovery capability, delivering a charge capacity of 934.4, 798.6, 661.4, 451.9, 403.4, 268.9 and 193.1 mAh g−1 at 0.2, 0.4, 0.8, 2, 3, 4 and 5 C, respectively, and a recovery capacity of up to 1166 mAh g−1 after 255 cycles from 0.1 to 5 C. Combining the experimental data with voltage profiles and CV curves, conversion reactions of the resulted FeCO3 are inferred to be not limited to the transition between FeCO3 and Li2CO3 but involving further reduction of Li2CO3. All the results suggest that the obtained FCO/GNS nanocomposite is a very promising anode material for lithium ion batteries

  4. Sodium citrate-assisted anion exchange strategy for construction of Bi2O2CO3/BiOI photocatalysts

    International Nuclear Information System (INIS)

    Highlights: • Heterostructured Bi2O2CO3/BiOI microspheres were prepared via anion exchange. • Sodium citrate-assisted anion exchange for construction of composite photocatalysts. • Bi2O2CO3/BiOI composites show high visible light photocatalytic activity. - Abstract: Bi2O2CO3/BiOI heterojuncted photocatalysts were constructed through a facile partial anion exchange strategy starting from BiOI microspheres and urea with the assistance of sodium citrate. The content of Bi2O2CO3 in the catalysts was regulated by modulating the amount of urea as a precursor, which was decomposed to generate CO32− in the hydrothermal process. Citrate anion plays a key role in controlling the morphology and composition of the products. The Bi2O2CO3/BiOI catalysts display much higher photocatalytic activity than pure BiOI and Bi2O2CO3 towards the degradation of rhodamine B (RhB) and bisphenol A (BPA). The enhancement of photocatalytic activity of the heterojuncted catalysts is attributed to the formation of p–n junction between p-BiOI and n-Bi2O2CO3, which is favorable for retarding the recombination of photoinduced electron-hole pairs. Moreover, the holes are demonstrated to be the main active species for the degradation of RhB and BPA

  5. 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.

  6. 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。

  7. 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.

  8. 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.

  9. 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...

  10. 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...

  11. Sensing Properties of Pd-Loaded Co3O4 Film for a ppb-Level NO Gas Sensor

    OpenAIRE

    Takafumi Akamatsu; Toshio Itoh; Noriya Izu; Woosuck Shin; Kazuo Sato

    2015-01-01

    We prepared 0.1 wt%–30 wt% Pd-loaded Co3O4 by a colloidal mixing method and investigated the sensing properties of a Pd-loaded Co3O4 sensor element, such as the sensor response, 90% response time, 90% recovery time, and signal-to-noise (S/N) ratio, toward low nitric oxide (NO) gas levels in the range from 50 to 200 parts per billion. The structural properties of the Pd-loaded Co3O4 powder were investigated using X-ray diffraction analysis and transmission electron microscopy. Pd in the powder...

  12. 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

  13. 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

  14. 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.

  15. Biosynthesis of P(3HB-co-3HV-co-3HHp terpolymer by Cupriavidus necator PHB-4 transformant harboring the highly active PHA synthase gene of Chromobacterium sp. USM2

    Directory of Open Access Journals (Sweden)

    Rathi, D-N.

    2013-01-01

    Full Text Available Aims: This study evaluates potentials of Cupriavidus necator PHB4 transformant harboring the highly activepolyhydroxyalkanoate synthase gene (phaC of a locally isolated Chromobacterium sp. USM2 for its ability toincorporate 3-hydroxyheptanoate (3HHp monomer.Methodology and results: A mixture of fructose and sodium heptanoate fed to the culture gave rise to poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyheptanoate, [P(3HB-co-3HV-co-3HHp] terpolymer synthesis, withtraces of 3HHp monomers confirmed through gas chromatography (GC, proton (1H and carbon (13C NMR spectra.Conclusion, significance and impact of study: This study has revealed that the PHA synthase of Chromobacteriumsp. USM2 has a broad range of substrate specificity. The synthase is able to polymerize 3-hydroxyalkanoate monomershaving 4–7 carbon atoms.

  16. 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...

  17. Study of the Li2CO3 as thermal neutrons detector

    International Nuclear Information System (INIS)

    The use every day but it frequents of the thermal neutrons in the treatment of tumours, using the neutron capture therapy technique in boron, there is generated the necessity to develop a dosimetric system that allows to evaluate in a reliable way the fluence and consequently the dose of neutrons that it is given in the tumours of the patients. One of the techniques but employees to determine the neutron fluence sub cadmic and epi cadmic in an indirect way, it is the activation of thin sheets of gold undress and covered with cadmium respectively that when being exposed to a neutron beam to the nuclear reaction 197Au (n, γ ) 198 Au, emitting gamma radiation with an energy of 0.4118 MeV, being this, a disadvantage to be used as dosemeter. On the other hand, when exposing the lithium carbonate to a thermal neutron beam, free radicals of CO3 that are quantified by the electron paramagnetic resonance technique are generated. This work analyzes those basic parameters that determine if those made up of Li2CO3 complete with the requirements to be used as detectors and/or dosemeters of thermal neutrons. (Author)

  18. 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.

  19. Synthesis of morphology-controllable mesoporous Co3O4 and CeO2

    International Nuclear Information System (INIS)

    Recently, extensive works have been devoted to the morphology control of mesoporous materials with respect to their use in various applications. In this paper, we used two kinds of mesoporous silica, SBA-15 rods and spheres as hard templates to synthesize morphology-controllable mesoporous metal oxides. By carefully controlling the loading of metal precursors in the mesopores of the hard template, mesoporous Co3O4 and CeO2 with different morphologies, such as micrometer-sized rod, hollow sphere, saucer-like sphere, and solid sphere were conveniently obtained. The structural properties of these materials were characterized by XRD, BET, SEM and TEM. In addition, it is found that the differences observed in the textural properties of the two mesoporous metal oxides nanocasted from the same template can be attributed to the properties of metal precursors and the interaction between metal oxide and SiO2. Thus-obtained mesoporous metal oxides with such special morphologies may have a potential application in the field of environmental catalytic oxidation. - Graphical Abstract: Mesoporous Co3O4 and CeO2 with different morphologies, such as micrometer-sized rod, hollow sphere, saucer-like sphere, and solid sphere were synthesized by nanocasting.

  20. 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...

  1. 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.

  2. Monolayer Co3 O4 Inverse Opals as Multifunctional Sensors for Volatile Organic Compounds.

    Science.gov (United States)

    Lee, Chul-Soon; Dai, Zhengfei; Jeong, Seong-Yong; Kwak, Chang-Hoon; Kim, Bo-Young; Kim, Do Hong; Jang, Ho Won; Park, Joon-Shik; Lee, Jong-Heun

    2016-05-17

    Monolayers of periodic porous Co3 O4 inverse opal (IO) thin films for gas-sensor applications were prepared by transferring cobalt-solution-dipped polystyrene (PS) monolayers onto sensor substrates and subsequent removal of the PS template by heat treatment. Monolayer Co3 O4 IO thin films having periodic pores (d≈500 nm) showed a high response of 112.9 to 5 ppm C2 H5 OH at 200 °C with low cross-responses to other interfering gases. Moreover, the selective detection of xylene and methyl benzenes (xylene+toluene) could be achieved simply by tuning the sensor temperature to 250 and 275 °C, respectively, so that multiple gases can be detected with a single chemiresistor. Unprecedentedly high ethanol response and temperature-modulated control of selectivity with respect to ethanol, xylene, and methyl benzenes were attributed to the highly chemiresistive IO nanoarchitecture and to the tuned catalytic promotion of different gas-sensing reactions, respectively. These well-ordered porous nanostructures could have potential in the field of high-performance gas sensors based on p-type oxide semiconductors. PMID:27125495

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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

  8. Structural study in ceramic multiferroic Co3TeO6 and analysis of possible Co-Co networks

    International Nuclear Information System (INIS)

    We show that there exist four networks (Co1-Co4, Co2-Co3-Co5, Co1-Co5 and Co2-Co3-Co4) in contrast to earlier observations of two networks (Co1-Co4 and Co2-Co3-Co5) in Co3TeO6 (CTO) multiferroic [Phys. Rev. B 88, 184427 (2013)]. Due to five crystallographically different sites of Co ions coordinated by [IV], [V] and [VI] oxygen atoms, the coordination polyhedra exhibit strong distortions from their respective ideal polyhedra, and thus potentially allow to resolve low-symmetry crystal field splittings of d-d electronic transitions. Our structural analysis using Rietveld refinements on the room temperature Synchrotron X-ray Diffraction data indicates possible magnetic order, and may provide a basis for the complex and multiple magnetic transitions of CTO at low temperature

  9. 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。

  10. 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.

  11. A facile route to controlled synthesis of Co3O4 nanoparticles and their environmental catalytic properties

    International Nuclear Information System (INIS)

    Using ammonia and Co(CH3COO)2·4H2O as starting materials, a facile and surfactant-free route to controlled synthesis of Co3O4 nanoparticles was proposed. Co3O4 nanoparticles with average sizes of 3.5, 6, 11, 19 and 70 nm were obtained through adjusting the ethanol amount in the solvent (the ratio of ethanol to water) or the concentration of raw materials. In this process, the presence of enough O2 was crucial for the formation of pure Co3O4 phase. The environmental catalytic properties of as-obtained Co3O4 nanoparticles were investigated. The results indicated their remarkable catalysis for ozonation degradation of phenol, which denoted a promising application as catalyst in waste-water treatment

  12. The critical re-evaluation of the aromatic/antiaromatic nature of Ti3(CO)3: a missed opportunity?

    Science.gov (United States)

    Foroutan-Nejad, Cina; Shahbazian, Shant; Rashidi-Ranjbar, Parviz

    2011-03-14

    The nature of bonding and aromaticity of Ti(3)(CO)(3), a mill-shaped metal-carbonyl complex, is studied carefully. A unique bonding mechanism between metal and carbonyl groups is found in this species. Ti(3)(CO)(3) is an example of a metal-carbonyl complex with prominent metal to carbonyl donation. Moreover, it is proven that not only is Ti(3)(CO)(3) not an antiaromatic complex but also it is the first synthesized example of d-block, σ+π aromatic species. A quick survey among the first row of transition metals in the periodic table shows that other local minima with similar structures and aromaticity are present and Ti(3)(CO)(3) is the first synthesized species of an unknown family. PMID:21279217

  13. 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.

  14. 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.

  15. Facile and Eco-Friendly Synthesis of Finger-Like Co3O4 Nanorods for Electrochemical Energy Storage

    Directory of Open Access Journals (Sweden)

    Shijiao Sun

    2015-12-01

    Full Text Available Co3O4 nanorods were prepared by a facile hydrothermal method. Eco-friendly deionized water rather than organic solvent was used as the hydrothermal media. The as-prepared Co3O4 nanorods are composed of many nanoparticles of 30–50 nm in diameter, forming a finger-like morphology. The Co3O4 electrode shows a specific capacitance of 265 F g−1 at 2 mV s−1 in a supercapacitor and delivers an initial specific discharge capacity as high as 1171 mAh g−1 at a current density of 50 mA g−1 in a lithium ion battery. Excellent cycling stability and electrochemical reversibility of the Co3O4 electrode were also obtained.

  16. Potential influence of sea cucumbers on coral reef CaCO3 budget: A case study at One Tree Reef

    Science.gov (United States)

    Schneider, Kenneth; Silverman, Jacob; Woolsey, Erika; Eriksson, Hampus; Byrne, Maria; Caldeira, Ken

    2011-12-01

    To endure, coral reefs must accumulate CaCO3 at a rate greater or equal than the sum of mechanically, biologically, and chemically mediated erosion rates. We investigated the potential role of holothurians on the CaCO3 balance of a coral reef. These deposit feeders process carbonate sand and rubble through their digestive tract and dissolve CaCO3 as part of their digestive process. In aquarium incubations with Stichopus herrmanni and Holothuria leucospilota total alkalinity increased by 97 ± 13 and 47 ± 7 μmol kg-1, respectively. This increase was due to CaCO3 dissolution, 81 ± 13 and 34 ± 6 μmol kg-1 and ammonia secretion, 16 ± 2 and 14 ± 2μmol kg-1, respectively, for these species. Surveys conducted at a long-term monitoring site of community calcification (DK13) on One Tree Reef indicated that the density of sea cucumbers was approximately 1 individual m-2. We used these data and data from surveys at Shark Alley to estimate the dissolution of CaCO3 by the sea cucumbers at both sites. At DK13 the sea cucumber population was estimated to be responsible for nearly 50% of the nighttime CaCO3 dissolution, while in Shark Alley for most of the nighttime dissolution. Thus, in a healthy reef, bioeroders dissolution of CaCO3 sediment appears to be an important component of the natural CaCO3 turnover and a substantial source of alkalinity as well. This additional alkalinity could partially buffer changes in seawater pH associated with increasing atmospheric CO2 locally, thus reducing the impact of ocean acidification on coral growth.

  17. 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.

  18. 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

  19. Formation of Co3O4 microframes from MOFs with enhanced electrochemical performance for lithium storage and water oxidation.

    Science.gov (United States)

    Feng, Yi; Yu, Xin-Yao; Paik, Ungyu

    2016-05-01

    Co3O4 microframes are synthesized through a template-engaged strategy via the etching of Co-Co Prussian blue analogue microcubes with ammonia solution and subsequent annealing treatment. Benefitting from their unique structural merits including 3D open structure and high porosity, these Co3O4 microframes exhibit enhanced electrochemical properties for both lithium-ion batteries and water oxidation. PMID:27078114

  20. Synthesis of one-dimensional porous Co3O4 nanobelts and their ethanol gas sensing properties

    International Nuclear Information System (INIS)

    Graphical abstract: 1D porous porous Co3O4 nanobelts were synthesized via a facile route without use of any surfactants or organic solvent, exhibiting ethanol gas sensing properties superior to the commercial Co3O4 powders. - Highlights: • One-dimensional porous Co3O4 nanobelts were synthesized. • The belt-like morphology can be finely controlled via adjusting the reaction parameters. • The evolution process of porous Co3O4 nanobelts was investigated. • Porous Co3O4 nanobelts exhibit superior ethanol gas sensing properties. - Abstract: In this paper, one-dimensional porous Co3O4 nanobelts were synthesized via a facile template-free hydrothermal method and subsequent the thermal decomposition. Their microstructures and morphologies were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and N2 adsorption–desorption techniques. The results indicate that the reaction parameters such as the molar ratio of Co(NO3)2·6H2O to C2H4N4, the amount of Co(NO3)2·6H2O, the hydrothermal temperature and time play crucial rules in controlling the microstructures and morphologies of the as-prepared cobalt precursors. A possible formation mechanism was proposed. Moreover, the obtained porous Co3O4 nanobelts exhibit ethanol gas sensing properties superior to the commercial Co3O4 powders at a working temperature of 200 °C, suggesting their potential applications as nanosensors

  1. Effects of solvent on the morphology of nanostructured Co3O4 and its application for high-performance supercapacitors

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Nano-structured cobalt oxides (Co3O4) with various morphologies (sheet-like, herbs-like and net-like) synthesized on the surfaces of nickel foam via a facile solvothermal method. • Ethanol, ethylene glycol (EG) and glycerol (GR) were used to investigate the effects of solvent on the size and morphology of nanocrystals in detail. • The open structure improves the contact between the electrode and the electrolyte. • Results showed that net-like Co3O4 have good electrochemical property. - Abstract: Nano-structured cobalt oxides (Co3O4) with various morphologies (sheet-like, herbs-like and net-like) have been in situ synthesized on the surface of nickel foam via a facile solvothermal method. Ethanol, ethylene glycol (EG) and glycerol (GR) were used to investigate the effects of solvent on the size and morphology of nanocrystals in detail. The possible formation mechanisms have been proposed that the dielectric constants and viscosity of solvents is speculated to be the main factor to determine the morphology of Co3O4 crystal. Applied for supercapacitor, the fabricated Co3O4 electrodes show the desired properties of macroporosity, allowing facile electrolyte flow and fast electrochemical reaction kinetics. Results show that the nanonet-like Co3O4 electrode synthesized in glycerol solvothermal condition has the highest capacitance (1063 F/g at a discharge current density of 10 mA/cm2), and good rate capability, excellent electrochemical stability (90.8% retention after 1000 cycles). The enhanced electrochemical performance is attributed to the open and ultrathin nanostructure of net-like Co3O4 electrode, which facilitates the electron transport. The findings in this work demonstrate the importance of solvents used for solvothermal reaction, and are meaningful in understanding the self-assembly process of various Co3O4 nanostructures

  2. Synthesis of carbon-coated Co3O4 composite with dendrite-like morphology and its electrochemical performance for lithium-ion batteries

    International Nuclear Information System (INIS)

    Carbon-coated Co3O4 microparticles (Co3O4-C) with dendrite-like morphology are prepared by a low-temperature hydrothermal method and subsequent C2H2 chemical vapor deposition (CVD) for the first time. The synthesized precursor Co3O4 has a size of 8–10 μm, which is assembled by lots of aligned Co3O4 wire with 4–5 μm in length. After carbon coating, Co3O4 microparticles were proved to be coated in amorphous carbon of ∼10 nm. A plausible formation process of the dendrite-like Co3O4 and Co3O4-C is proposed based on the morphology and structure characterizations of the materials. As an anode material for lithium-ion batteries, the Co3O4-C composite electrode exhibits higher reversible capacity and better cycling performance than the unmodified Co3O4 electrode. The reversible capacity of the Co3O4-C composite after 40 cycles is 500 mAh g−1, much higher than that of Co3O4 (148 mAh g−1). Electrochemical impedance spectra and cyclic voltammogram indicate that the carbon layer coated on Co3O4 by CVD can improve the electrochemical activity and enhance the reversibility of Co3O4 during charge/discharge cycles.

  3. 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。

  4. One-pot facile synthesis and optical properties of porous La2O2CO3 hollow microspheres

    International Nuclear Information System (INIS)

    Graphical abstract: . Display Omitted Research highlights: → Porous hollow La2O2CO3 microspheres have been synthesized via a one-pot hydrothermal treatment. → Carbon microspheres act as not only templates but also carbon sources. → La2O2CO3 hollow spheres show a green emission band under UV excitation. - Abstract: Lanthanum oxycarbonate (La2O2CO3) hollow microspheres with novel porous architectures were successfully fabricated by a simple one-pot hydrothermal treatment of an aqueous solution containing glucose, La(NO3)3.6H2O, and subsequent calcination. The as-prepared La2O2CO3 porous hollow spheres are composed of nanoparticles with a mean particle size of 15 nm. Carbon microspheres act as not only templates but also carbon sources for the formation of La2O2CO3 hollow spheres. Interestingly, the as-prepared La2O2CO3 hollow spheres show a green emission band under UV excitation, which may be used as fluorescent biological labels.

  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. The facettes of [99TcCl3(CO)3]2- chemistry and its application to life science

    International Nuclear Information System (INIS)

    This article gives a brief summary about the current status of radiochemistry and radiopharmaceutical chemistry as related to the fac-[99mTc(OH2)3(CO)3]+ and fac-[99Tc(OH2)3(CO)3]+ synthon. Since the synthesis and availability of synthons or direct precursors for the labeling of biomolecules (and for the exploration of fundamental inorganic and organometallic chemistry) is a crucial prerequisite for developing new radiopharmaceuticals, some consideration about composition and characteristics of such complexes are discussed at the beginning and their suitability is discussed. Beside widely investigated basic and applied Tc chemistry in the oxidation state (V) with the [Tc=O]3+ or [Tc≡N]2+ moieties, the aforementioned [99(m)Tc(CO)3]+ and [99Tc(CO)3]+ core are new members in this group. Although is pressureless synthesis from organic solvents has been described about eight years ago, it is only recently that exploitation of its radiopharmaceutical potential could reasonably start owing to the availability of a routinely applicable kit. We will summarize basic coordination chemistry of the [99(m)Tc(CO)3)]+ and [99Tc(CO)3)]+ moieties as relevant for radiopharmaceutical purposes, focusing on some fundamental reactions in the context of low valent Tc chemistry. Due to its special properties, new research directions possible only through its very special physico-chemical properties will be emphasized as well. (author)

  7. 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

  8. Observation of high-spin mixed oxidation state of cobalt in ceramic Co3TeO6

    International Nuclear Information System (INIS)

    We report coexistence of high spin Co3+ and Co2+ in ceramic Co3TeO6 using X-ray Absorption Near Edge Structure (XANES), DC magnetization, and first principles ab-initio calculations. The main absorption line of cobalt Co K-edge XANES spectra, along with a linear combination fit, led us to estimate relative concentration of Co2+ and Co3+as 60:40. The pre edge feature of XANES spectrum shows crystal field splitting of ∼1.26 eV between eg and t2g states, suggesting a mixture of high spin states of both Co2+ and Co3+. Temperature dependent high field DC magnetization measurements reveal dominant antiferromagnetic order with two Neel temperatures (TN1 ∼ 29 K and TN2 ∼ 18 K), consistent with single crystal study. A larger effective magnetic moment is observed in comparison to that reported for single crystal (which contains only Co2+), supports our inference that Co3+ exists in high spin state. Furthermore, we show that both Co2+ and Co3+ being in high spin states constitute a favorable ground state through first principles ab-initio calculations, where Rietveld refined synchrotron X-ray diffraction data are used as input

  9. 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.

  10. 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.

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

    Science.gov (United States)

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

    2016-05-01

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

  12. 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.

  13. A study on labelling of bioactive molecules using 99mTc(CO)3(H2O)3+ precursor

    International Nuclear Information System (INIS)

    To radiolable bioactive molecules, we synthesized 99mTc precursor, 99mTc(CO)3(H2O)3+ with a low oxidation state (1). We evaluated the characteristics of bioactive molecules labeled with precursor using in vitro and in vivo study. The 99mTc(CO)3(H2O)3+ was synthesized by low pressure carbonylation (1 atm CO) of 99mTcO)4- in the presence of NaBH4 with high labeling yield (>98%) and stability up to 8 hrs. A prepared 99mTc(CO)3(H2O)3+ was reacted with common ligands for 99mTc labeling and amino acids to investigate labeling property of 99mTc(CO)3(H2O)3+. And we also assessed the biodistribution property of 99mTc(CO)3(H2O)3+-complexes in rabbit. 99mTc-tricarbonyl complexes with ligands for 99mTc labeling was also easily prepared and the properties of biodistribution differ between 99mTc-tricarbonyl labeling group and 99mTc labeling one. From these results, we concluded that 99mTc(CO)3(H2O)3+ and 99mTc-tricarbonyl complex is a potential precursor for the development of radiopharmaceuticals, especially for labeling of biomolecules

  14. Synthesis of PtCo3 polyhedral nanoparticles and evolution to Pt3Co nanoframes

    Science.gov (United States)

    Becknell, Nigel; Zheng, Cindy; Chen, Chen; Yu, Yi; Yang, Peidong

    2016-06-01

    Bimetallic nanoframes have great potential for achieving new levels of catalytic activity in various heterogeneous reactions due to their high surface area dispersion of expensive noble metals on the exterior and interior surfaces of the structure. PtCo3 nanoparticles with polyhedral shapes were synthesized by a hot-injection method. Scanning transmission electron microscopy combined with energy dispersive X-ray spectroscopy (EDS) showed that these nanoparticles demonstrated elemental segregation of platinum to the edges of the polyhedron, forming the basis for a framework nanostructure. The process of preferential oxidative leaching which removed cobalt from the interior of the framework was tracked by EDS and inductively coupled plasma optical emission spectroscopy. This evolution procedure left the platinum-rich edges intact to form a Pt3Co nanoframe. This is the first reported synthesis of a platinum-cobalt nanoframe and could have potential applications in catalytic reactions such as oxygen reduction.

  15. 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.

  16. The effect of crystallinity on photocatalytic performance of Co3O4 water-splitting cocatalysts.

    Science.gov (United States)

    Chua, Chin Sheng; Ansovini, Davide; Lee, Coryl Jing Jun; Teng, Yin Ting; Ong, Lay Ting; Chi, Dongzhi; Hor, T S Andy; Raja, Robert; Lim, Yee-Fun

    2016-02-21

    Cocatalysts, when loaded onto a water splitting photocatalyst, accelerate the gas evolution reaction and improve the efficiency of the photocatalyst. In this paper, we report that the efficiency of the photocatalyst is enhanced using an amorphous cobalt oxide cocatalyst. The WO3 film, when loaded with amorphous or nanocrystalline Co3O4, shows an improvement of up to 40% in photocurrent generation and 34% in hydrogen gas evolution. The effect of cocatalyst crystallinity on performance was systematically studied, and we found that the photocurrent deteriorates with the conversion of the cocatalyst to a highly crystalline phase at an annealing temperature of 500 °C. The mechanism of this effect was studied in detail using electrochemical impedance spectroscopy, and the enhancement effect produced by the amorphous cocatalyst is attributed to the large density of unsaturated catalytically active sites in the amorphous material. PMID:26805577

  17. 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.

  18. 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.

  19. 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.

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

    Science.gov (United States)

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

    2016-02-01

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

  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. [99mTc(CO)3] - BiotinNTA derivative for tumor pretargeting

    International Nuclear Information System (INIS)

    Tumor pretargeting using monoclonal antibodies in combination with biotin, labeled with radionuclides, could be useful for cancer diagnosis and treatment. Biotin nitrilrotriacetic acid (BiotinNTA) having functional groups of three -COOH was used as biotin derivative for antibody pretargeting strategies. In this investigation, 99mTc(CO)3-BiotinNTA was prepared to determine its potential use in antibody pretargeting strategies for tumor diagnosis. 99mTc is considered to be ideal radionuclides for the development of radioimaging of tumor. Radiolabeling of the BiotinNTA was performed in PBS buffer (pH=7.4) at 75 .deg. C, 30 min. The radiolabeling efficiency and radiochemical purity were analyzed by a reverse-phase high performance liquid chromatography (RP-HPLC). The radiolabeled complex was tested in vitro for stability in plasma and biological affinity against avidin using magnetic particle seperator in PBS buffer (pH7.4)

  4. 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.

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

    Science.gov (United States)

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

    2016-05-01

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

  6. 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.

  7. 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

  8. Crystal field and magnetization of canted antiferromagnet CoCO3

    International Nuclear Information System (INIS)

    The magnetization of the canted antiferromagnet CoCO3 (TN = 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 TN, 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

  9. Radiolabeling RGD-peptide using fac-[188Re(CO)3(H2O)3]+

    International Nuclear Information System (INIS)

    Integrin αvβ3 is a member of the integrin family, which plays an important role in angiogenesis and tumour metastasis. The peptides containing arginine-glycine-aspartic acid(RGD) sequence can bind to integrin αvβ3 selectively. In the present study, we labeled two RGD-peptides via fac-[188Re(CO)3(H2O)3]+. The results show that the labeling yields are more than 90% for both of radiolabeled compounds, and they are all stable in phosphate buffered saline and new-born calf serum, even challenged in histidine or cysteine solution. We will evaluate their biological properties to develop radiolabeled agents for tumor therapy. (authors)

  10. The electrolytic deposition of carbon from molten Li2CO3

    International Nuclear Information System (INIS)

    Electrodeposition of carbon on an nickel electrode in molten salt has been investigated with the aid of scanning electron microscopy (SEM) and cyclic voltammetry, using molten LiCl, as a base electrolyte with adding of 1 and 5 % of Li2CO3. Commercial nickel wire was used as a cathode and graphite crucible as the anode electrode. A cyclic voltammograms for an nickel electrode indicates that the deposition or discharge of carbon at the cathode occurs at potential range of - 0.8 to -1.7 V. Further, SEM observations showed that morphology of the carbon at the cathode is in the form of a fairly hard black deposit. It was found that the quality of the deposit depends by the cathode surface, applied overpotential, content of lithium carbonate and the thickness of the carbon film. (Original)

  11. 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

  12. 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

  13. 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 %.

  14. 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

  15. 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.

  16. 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.

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

    Science.gov (United States)

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

    2012-12-01

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

  18. A recyclable and highly active Co3O4 nanoparticles/titanate nanowire catalyst for organic dyes degradation with peroxymonosulfate

    International Nuclear Information System (INIS)

    Sodium ions of TNWs were exchanged with hydrogen ions, and this protocol was very suitable for capturing high density of cobalt ions. Meanwhile, the fabricated Co3O4/TNWs nano-material presented a highly catalytic and stable activity for dye degradation. - Highlights: • Co3O4 nanoparticles were deposited on the pretreated TNWs surface. • The TNWs treated by hydrogen ions captures higher density of cobalt ions. • The Co3O4/TNWs catalyst possesses highly efficiency for dyes degradation with oxone. - Abstract: In this paper, we reported a recyclable and highly active porous catalyst of titanate nanowires (TNWs) coated with well-distributed Co3O4 nanoparticles (NPs) (Co3O4/TNWs). Sodium ions of TNWs were exchanged with hydrogen ions in the dilute nitric acid, and this protocol was very suitable for capturing cobalt ions. X-ray diffraction (XRD) demonstrated the existence of Co3O4 phase with unique lattice planes, such as (2 2 0), (3 1 1) and (5 1 1). Electron microscopes (FE-SEM and TEM) indicated that the Co3O4 NPs with an average diameter of 22 ± 3 nm were coated uniformly on TNWs surface (average diameter: 37 ± 5.5 nm), and the Co3O4 NPs mainly exposed their (2 2 0) and (2 2 2) active planes. XPS analysis confirms the formation of Co3O4 phase by the presence of Co 2p peaks at 780.1 eV (2p 3/2) and 795.5 eV (2p 1/2). Methylene blue (MB) and other organic dyes (rhodamine B (RhB) and methyl orange (MO)) were chosen as target compounds for catalytic degradation under indoor scattering light. Compared to the original Co3O4/TNWs catalyst, the catalytic efficiency of nanoscaled catalyst with oxone for MB was about 15 times higher, and the MB solution (10 mg L−1) was completely degraded within 8 min. The catalytic activity of recycled catalyst used in the sixth run still remained very active, and the degradation time for MB was only 16 min. The nanosized catalyst also had a high activity for dyes of RhB (10 mg L−1) and MO (10 mg L−1), as the degradation

  19. 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.

  20. 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

  1. 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...

  2. 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.

  3. 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.

  4. 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

  5. Radiosynthesis and biological evolution of 99mTc(CO)3-sitafloxacin dithiocarbamate complex. A promising Staphylococcus aureus infection radiotracer

    International Nuclear Information System (INIS)

    Radio-complexation of sitafloxacin dithiocarbamate (SFDE) with technetium-99m (99mTc) using [99mTc(OH2)3(CO)3]+ precursor was investigated and compared with the 99mTc labeled SFDE prepared through 99mTcN core. The 99mTc(CO)3-SFDE radiocomplex was assessed in terms of radiochemical purity (RCP), eternalness in serum, in vitro binding with Staphylococcus aureus (S. aureus) and biodistribution in artificially Staphylococcus aureus infected rats (SAIR). The feasibility of the 99mTc(CO)3-SFDE radiocomplex as a suitable S. aureus infection radiotracer was evaluated in SAIR. The complex showed maximum RCP of 98.45 ± 0.21% in saline and was remained tagged more than 90% up to 4 h. The complex was found stable in serum and after 16 h only 17.95% de-tagged radio-fractions was observed. Similar saturated in vitro binding behaviour was observed for both the radiocomplexes (99mTc(CO)3-SFDE and 99mTcN-SFDE) with living S. aureus. Both the radiocomplexes showed almost similar in vivo biodistribution in SAIR. Significantly higher but similar infected to normal muscle ratio was observed for both the radiocomplexes in SAIR. The results of radiochemical purity (RCP), eternalness in serum, in vitro binding and in vivo biodistribution in SAIR posed the 99mTc(CO)3-SFDE radiocomplex as suitable S. aureus infection radiotracer. (author)

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

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

    OpenAIRE

    Yusheng Xin; Zixuan Wang; Lu Xu; Xiaowei Xu; Yang Liu; Fujun Zhang

    2013-01-01

    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, a...

  14. 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.

  15. 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....

  16. Electronic structures and magnetic moments of Co3FeN thin films grown by molecular beam epitaxy

    International Nuclear Information System (INIS)

    We evaluated electronic structures and magnetic moments in Co3FeN epitaxial films on SrTiO3(001). The experimentally obtained hard x-ray photoemission spectra of the Co3FeN film have a good agreement with those calculated. Site averaged spin magnetic moments deduced by x-ray magnetic circular dichroism were 1.52 μB per Co atom and 2.08 μB per Fe atom at 100 K. They are close to those of Co4N and Fe4N, respectively, implying that the Co and Fe atoms randomly occupy the corner and face-centered sites in the Co3FeN unit cell

  17. 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.

  18. 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).

  19. Syntheses and characterization of Sr(OH)2 and SrCO3 nanostructures by ultrasonic method.

    Science.gov (United States)

    Alavi, Mohammad Amin; Morsali, Ali

    2010-01-01

    The Sr(OH)(2) and SrCO(3) nanostructures were synthesized by reaction of strontium(II) acetate and sodium hydroxide or tetramethylammonium hydroxide (TMAH) via ultrasonic method. Reaction conditions, such as the concentration of the Sr(2+) ion, aging time, power of the ultrasonic device and alkali salts show important roles in the size, morphology and growth process of the final products. The pure crystalline SrCO(3) were obtained by heating of product at 400 degrees C. The Sr(OH)(2) and SrCO(3) nanostructures were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), thermal gravimetric (TG), differential thermal analyses (DTA) and the infrared spectroscopy (IR). PMID:19501537

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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)

  7. 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)

  8. 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.

  9. 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

  10. 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.

  11. Graphene-Immobilized fac-Re(bipy)(CO)3Cl for Syngas Generation from Carbon Dioxide.

    Science.gov (United States)

    Zhou, Xin; Micheroni, Daniel; Lin, Zekai; Poon, Christopher; Li, Zhong; Lin, Wenbin

    2016-02-17

    We report the synthesis of fac-M(4-amino-bipy)(CO)3X (M = Mn and X = Br or M = Re and X = Cl, with bipy = 2,2'-bipyridine), their immobilization on graphene oxide (GrO) via diazonium grafting, and the use of Re-functionalized GrO for electrocatalytic syngas production. Infrared (IR) spectroscopy, X-ray absorption fine structure (XAFS) spectroscopy, and electrocatalysis indicated successful grafting of the Re catalyst onto GrO. Re-functionalized GrO was then deposited onto a glassy carbon electrode (GCE) for CO2 reduction. Investigation of the Re-functionalized GCE for syngas production was performed in a CO2-saturated acetonitrile solution with 3.1 M H2O as the proton source and 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF6) as the supporting electrolyte. Cyclic voltammetry (CV), controlled potential electrolysis (CPE), and gas chromatography (GC) were employed to determine its CO2-to-CO conversion performance. The Re catalyst shows a turnover frequency (TOF) for generating CO up to 4.44 s(-1) with a CO/H2 ratio of 7:5. PMID:26799656

  12. Patterns of biomediated CaCO3 crystal bushes in hot spring deposits

    Science.gov (United States)

    Peng, Xiaotong; Jones, Brian

    2013-08-01

    In the Eryuan hot spring, located in south China, the vent pool is covered with “crystal bushes”, up to 2 cm high, 1 cm in diameter, that grew in the biofilms that thrive in the spring waters that have a pH of 7.5 and a temperature of 88 °C. The biofilms are formed largely of phototrophic purple bacteria and green bacteria. Growth of the crystal bushes, which are formed of aragonite crystals (wheat-sheaves, radiating clusters), rhombohedral and dodecahedral calcite crystals, amorphous CaCO3 (ACC), and opal-A, is attributed to precipitation in the micro-domains of the biofilms where physiochemical conditions can vary on the sub-micron scale. There is no evidence that the calcite was formed through recrystallization of the metastable aragonite and most of the calcite crystals developed as mesocrystals that are characterized by incomplete growth and porous crystal faces. With the onset of diagenesis, there is a high probability that the crystal bushes will lose much of their identity as the (1) biofilm is lost through decay, (2) ACC and aragonite change to calcite, (3) identities of the mesocrystals and incompletely formed crystals are lost through continued precipitation and/or recrystallization, and (4) porous crystal faces are converted to solid crystal faces. This means that most of the features considered indicative of biomediated calcite precipitation have a low preservation potential and that the recognition of biomediated precipitates in old spring deposits may remain problematical.

  13. 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.

  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. Template synthesis of 1D hierarchical hollow Co3O4 nanotubes as high performance supercapacitor materials

    International Nuclear Information System (INIS)

    Highlights: • Hollow Co3O4 nanotubes was prepared by using activated carbon as a hard template. • Typical Co3O4 nanotubes possess the hierarchical mesoporous nanostructure. • High specific capacitance of 1006 F g−1 is obtained at a current density of 1 A g−1. • Excellent electrochemical stability of 91% after 1000 charge–discharge cycles. - Abstract: One-dimensional (1D) hierarchical hollow Co3O4 nanotubes have been controllably fabricated via a facile two-step strategy including template-hydrothermal reaction and calcination, in which cobalt sulfate heptahydrate, guanidine hydrochloride and activated carbon are used as cobalt precursors, precipitant and hard template, respectively. The resultants of Co3O4 are characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED) patterns and N2 adsorption and desorption. The novel precipitant guanidine hydrochloride and hard template activated carbon contributed to the interesting morphology, and plus Kirkendall effect leading to producing hollow structure with hierarchical porous. The electrochemical properties of prepared different Co3O4 samples are evaluated and compared through cyclic voltammetry (CV), charge–discharge and electrochemical impedance spectroscopy (EIS) in 2.0 M KOH electrolytic solution. The results show that the 1D hierarchical hollow Co3O4 nanotubes exhibit a large specific capacitance of 1006 F g−1 at 1 A g−1, an outstanding cyclic stability with a capacitance retention of 91% after 1000 cycles of charge–discharge and a low resistance

  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. 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.

  18. A visible-light-driven core-shell like Ag2S@Ag2CO3 composite photocatalyst with high performance in pollutants degradation.

    Science.gov (United States)

    Yu, Changlin; Wei, Longfu; Zhou, Wanqin; Dionysiou, Dionysios D; Zhu, Lihua; Shu, Qing; Liu, Hong

    2016-08-01

    A series of Ag2S-Ag2CO3 (4%, 8%, 16%, 32% and 40% Ag2S), Ag2CO3@Ag2S (32%Ag2S) and Ag2S@Ag2CO3 (32%Ag2S) composite photocatalysts were fabricated by coprecipitation or successive precipitation reaction. The obtained catalysts were analyzed by N2 physical adsorption, powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, UV-vis diffuse reflectance spectroscopy and photocurrent test. Under visible light irradiation, the influences of Ag2S content and core-shell property on photocatalytic activity and stability were evaluated in studies focused on the degradation of methyl orange (MO) dye, phenol, and bisphenol A. Results showed that excellent photocatalytic performance was obtained over Ag2S/Ag2CO3 composite photocatalysts with respect to Ag2S and Ag2CO3. With optimal content of Ag2S (32 wt%), the Ag2S-Ag2CO3 showed the highest photocatalytic degradation efficiency. Moreover, the structured property of Ag2S/Ag2CO3 greatly influenced the activity. Compared with Ag2S-Ag2CO3 and Ag2CO3@Ag2S, core-shell like Ag2S@Ag2CO3 demonstrated the highest activity and stability. The main reason for the boosting of photocatalytic performance was due to the formation of Ag2S/Ag2CO3 well contacted interface and unique electron structures. Ag2S/Ag2CO3 interface could significantly increase the separation efficiency of the photo-generated electrons (e(-)) and holes (h(+)), and production of OH radicals. More importantly, the low solubility of Ag2S shell could effectively protect the core of Ag2CO3, which further guarantees the stability of Ag2CO3. PMID:27236845

  19. High Performance Supercapacitors Based on the Electrodeposited Co3O4 Nanoflakes on Electro-etched Carbon Fibers

    International Nuclear Information System (INIS)

    Graphical abstract: In the present work, excellent supercapacitive behavior of nanostructured Co3O4-ECF with outstanding cycling stability and capacitance retention was observed. These characteristics can be attributed to three dimensional (3D) structures of nanoflakes which allow facile electrolyte movement during charge or discharge processes. A specific capacitance of 598.9 F g(1 at a currents density of 3.1 A g(1 was obtained for Co3O4-ECF electrode in addition to high energy and power densities. - Highlights: • A facile method was introduced to prepare Co3O4 nanostructures for supercapacitor purpuoses. • Superior long-life stability and high specific capacitance at large current density were observed. • Capacitive behavior was remained almost constant after 1000 successive charge-discharge cycles. - Abstract: Present article introduces the electrochemical fabrication of cobalt oxide nanostructures on electro-etched carbon fiber (ECF) by a cathodic potential step method. The morphology and composition of the nanostructures were studied by field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDX), X-ray diffraction analysis (XRD) and thermal analysis (TA) methods. FE-SEM images confirm the formation of flower-like Co3O4 nanoflakes on ECF (Co3O4-ECF). Cobalt hydroxide nanostructures transform into spinel structure after annealing in air at 300 °C for 2 hours. The electrochemical and supercapacitive performance of Co3O4-ECF was investigated by cyclic voltammetry (CV), galvanostatic charge-discharge, and electrochemical impedance spectroscopy (EIS) in both three and two electrode systems in KOH solution. Results confirm the excellent supercapacitive behavior of nanostructured Co3O4-ECF with excellent cycling stability and capacitance retention. These characteristics can be attributed to three dimensional (3D) structures of nanoflakes which allow facile electrolyte movement during charge or discharge processes. A specific

  20. 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...

  1. 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...

  2. Study of the Na-Na2O-Na2CO3-C system phase diagram

    International Nuclear Information System (INIS)

    The aim of this study is to provide a contribution to the understanding of the sodium-carbon-oxygen ternary system in the sodium rich corner. The basic experimental technique used is differential thermal analysis (DTA) but it has been completed by quenching, X ray and chemical analysis methods. The proposed phases diagram implies that Na-Na2O-Na2CO3-C system is reciprocal ternary system. Temperature of stable pairs reversal is 690 deg. C. The stable pair is Na-Na2CO3 at elevated temperature and Na2O-C at low temperature. (author)

  3. 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

  4. 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%.

  5. 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。

  6. 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

  7. 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

  8. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) production by Haloarchaeon Halogranum amylolyticum.

    Science.gov (United States)

    Zhao, You-Xi; Rao, Zhi-Ming; Xue, Yan-Fen; Gong, Ping; Ji, Yi-Zhi; Ma, Yan-He

    2015-09-01

    Haloarchaea is an important group of polyhydroxyalkanoate (PHA)-accumulating organisms. However, few promising haloarchaeal species for economical and efficient PHA production have been reported. Here, we first discovered that Halogranum amylolyticum TNN58 could efficiently accumulate poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with a high 3-hydroxyvalerate (3HV) fraction using glucose as carbon source. Briefly, transmission electron microscopy (TEM) analysis revealed the presence of a large number of PHA granules in the cells. Gas chromatography-mass spectrometry (GC-MS) and proton nuclear magnetic resonance ((1)H NMR) analyses showed that PHAs synthesized from glucose was PHBV. Moreover, the 3HV content reached 20.1 mol%, which is the highest 3HV fraction thus far reported, as for PHBV produced by the wild-type strains grown on unrelated carbon courses. Fermentation experiments suggested that nitrogen-limited MG medium was better than nutrient-rich NOMG and AS168 medium for PHBV production. Additionally, glucose was the most suitable carbon source among the tested carbon sources. Interestingly, PHBV accumulation was almost paralleled by cell growth and glucose consumption. By applying the fed-batch process in fermentor, the PHBV production and cell dry weight were increased by approximately eight and four times, respectively, as compared with those of the batch process in shaking flasks. The classical PHA synthase genes were successfully cloned via consensus-degenerate hybrid oligonucleotide primers (CODEHOPs) and high-efficiency thermal asymmetric interlaced (hiTAIL) PCR methods. This finding suggested that H. amylolyticum shows promising potential in the low-cost biotechnological production of PHBV after further process optimization. PMID:25947242

  9. 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.

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

    Science.gov (United States)

    Dodenhof, Tanja; Dietz, Frank; Franken, Sebastian; Grunwald, Ingo; Kelm, Sørge

    2014-01-01

    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. PMID:24824517

  11. 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.

  12. Template Adaptability is Key in the Oriented Crystallization of CaCO3

    International Nuclear Information System (INIS)

    In CaCO3, biomineralization nucleation and growth of the crystals are related to the presence of carboxylate-rich proteins within a macromolecular matrix, often with organized β-sheet domains. To understand the interplay between the organic template and the mineral crystal it is important to explicitly address the issue of structural adaptation of the template during mineralization. To this end we have developed a series of self-organizing surfactants (1-4) consisting of a dodecyl chain connected via a bisureido-heptylene unit to an amino acid head group. In Langmuir monolayers the spacing of these molecules in one direction is predetermined by the hydrogen-bonding distances between the bis-urea units. In the other direction, the intermolecular distance is determined by steric interactions introduced by the side groups (-R) of the amino acid moiety. Thus, by the choice of the amino acid we can systematically alter the density of the surfactant molecules in a monolayer and their ability to respond to the presence of calcium ions. The monolayer films are characterized by surface pressure-surface area (p-A) isotherms, Brewster angle microscopy, in-situ synchrotron X-ray scattering at fixed surface area, and also infrared reflection absorption spectroscopy (IRRAS) of films transferred to solid substrates. The developing crystals are studied with scanning and transmission electron microscopy (SEM, TEM), selected area electron diffraction (SAED), and crystal modeling. The results demonstrate that although all compounds are active in the nucleation of calcium carbonate, habit modification is only observed when the size of the side group allows the molecules to rearrange and adapt their organization in response to the mineral phase.

  13. 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

  14. 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

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

    Directory of Open Access Journals (Sweden)

    K. S. Rodgers

    2009-02-01

    Full Text Available Acidification of seawater owing to oceanic uptake of atmospheric CO2 originating from human activities such as burning of fossil fuels and land-use changes has raised serious concerns for its adverse effects on corals, coral reefs and carbonate communities in general. Here we demonstrate a transition from net accumulation towards net loss of calcium carbonate (CaCO3 material owing to decreased calcification and increased carbonate dissolution from replicated subtropical coral reef communities (n=3 incubated in continuous-flow mesocosms subject to present and future seawater conditions. The calcifying community was dominated by the coral Montipora capitata. Daily average community calcification or Net Ecosystem Calcification (NEC = CaCO3 production – dissolution was positive at 4.5 mmol CaCO3 m−2 h−1 under ambient seawater pCO2 conditions as opposed to negative at −0.1 mmol CaCO3 m−2 h−1 under seawater conditions of double the ambient pCO2. These experimental results provide support for the conclusion that some net calcifying communities could become subject to net dissolution in response to anthropogenic ocean acidification within this century.

  16. 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.

  17. The quantitative analysis of ternary mixtures of anhydrous crystalline CaCO3 polymorphs using micro Raman spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Ševčík, Radek; Mácová, Petra; Pérez-Estébanez, Marta

    2015. [IMA2015. Instrumental Methods of Analysis-Modern Trends and Applications. 20.09.2015-24.09.2015, Kalamata] R&D Projects: GA ČR(CZ) GP14-20374P; GA MŠk(CZ) LO1219 Keywords : CaCO3 polymorphs * micro Raman spectroscopy * quantification Subject RIV: AL - Art, Architecture, Cultural Heritage

  18. Inter-diffusion between Co3O4 coatings and the oxide scale on Fe-22Cr

    International Nuclear Information System (INIS)

    The oxidation behaviour of a commercially available Fe-22Cr alloy coated with a Co3O4 layer by spray-painting or plasma-spraying was investigated at 1173 K in air with 1% H2O and compared to the oxidation behaviour of the non-coated alloy. The oxide morphology was examined with X-ray diffraction, electron microscopy, and energy dispersive X-ray spectroscopy. Cr2O3 developed in-between the Co3O4 coating and the alloy, whilst alloying elements of the substrate were incorporated in the coating, regardless of the deposition method. The coatings reduced the growth rate of the Cr2O3 layer as well as the evolution in contact resistance with time between two Fe-22Cr plates sandwiched around a Pt-mesh. SiO2 developed as particles within the alloy during oxidation of the Co3O4 spray-painted samples, whereas SiO2 was identified as an interfacial layer between Cr2O3 and the alloy after oxidation of the Co3O4 plasma-sprayed and the non-coated samples. The difference in morphology is suggested to be an effect of SiO2 nucleation assisted by Kirkendall void formation

  19. Crystal structures of new cuprates containing CO3 analyzed by the Rietveld method of neutron powder diffraction

    International Nuclear Information System (INIS)

    New compounds containing CO3 groups, Sr2CuO2(CO3), (C0.4Cu0.6)Sr2(Y0.86Sr0.14)Cu2O7 and (C0.35Cu0.65)Sr2(Y0.73Ce0.27)2Cu2O9, were prepared as stable phases at 1273-1303 K in a flowing gas of O2-CO2. The crystal structures of these compounds were refined by means of the Rietveld analysis for neutron powder diffraction data collected using a high resolution powder diffractometer (HRPD) in the JRR-3M reactor hall of the Japan Atomic Energy Research Institute (JAERI). Positions of CO3 groups were satisfactorily determined. The distances of C-O bonds in the CO3 groups were around 1.3A and the O-C-O angles were almost equal to the ideal bond angle of 120deg. (author)

  20. 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.

  1. 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.

  2. 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

  3. Hierarchical Co3O4 Nanoparticles Embedded in a Carbon Matrix for Lithium-Ion Battery Anode Materials

    International Nuclear Information System (INIS)

    Highlights: • Co3O4 nanocrystals with size of 20 nm homogeneously embedded in the carbon matrix are successfully synthesized. • Cycle exceeds 400 times in half cells at a 5 C (5 Ag−1) rate while retaining about 1000 mAhg−1 reversible capacities. • Large rates up to 10 C for are achieved with high energy density. • Such Co3O4 exhibits excellent high-rate capability and cycling stability. - Abstract: A Co3O4-C nanocomposite has been synthesized by a one-step hydrothermal method free of any template with an annealing process. The composite exhibits a flower-like, hollow, and porous skeleton with a large specific surface area of 272.3 m2g−1. The scanning electron microscope (SEM) and transmission electron microscope (TEM) images reveal the hybrid nanostructure comprises ring-like Co3O4 nanocrystals of 20 nm in diameter homogeneously embedded in the carbon matrix. Such integrated electrodes exhibit an ultrahigh specific capacity and excellent cycling stability even at a high charge/discharge current density. Cycle exceeds 400 times in half cells at a 5 C (5 Ag−1) rate while retaining about 1000 mAhg−1 reversible capacities (where a 1 C rate represents a one-hour complete charge or discharge). This study not only provides a simple synthesis method for lithium ion batteries, but also helps in designing novel and high performance electrode materials

  4. 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; Linderoth, Søren; Somers, Marcel A. J.

    -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 of the...

  5. Co3O4-CeO2 mixed oxide-based catalytic materials for diesel soot oxidation

    Czech Academy of Sciences Publication Activity Database

    Dhakad, M.; Mitshuhashi, T.; Rayalu, S.; Doggali, P.; Bakardjieva, Snejana; Šubrt, Jan; Fino, D.; Haneda, H.; Labhsetwar, N.

    2008-01-01

    Roč. 132, 1-4 (2008), s. 188-193. ISSN 0920-5861 R&D Projects: GA MŠk LC523 Institutional research plan: CEZ:AV0Z40320502 Keywords : soot oxidation * diesel particulate * Co3O4-CeO2 type mixed oxide Subject RIV: CA - Inorganic Chemistry Impact factor: 3.004, year: 2008

  6. Study of the system: Lu(NO3)3-Rb2CO3-H2O

    International Nuclear Information System (INIS)

    The interaction in the Lu(NO3)3-Rb2CO3-H2O system at 25 deg C and molar relation (R)CO32-:Lu3+=0.5-20 is studied by the method of residual concentrations. From the data on chemical analysis it follows that depending on the R value three compounds are consequently formed in the system: Lu2(CO3)3x3H2O(1) (R=0.5-20); Rb(Lu(CO3)2)x2H2O(2) (R=2.5-5.0); Rb3(Lu(CO3)3))x6H2O(3) (R=3-10). The first two compounds are the precipitates, and the latter is the well-soluble salt. Thermal decomposition of compound 2 proceeds through stages of step-by-step dehydration in the 20-200 deg C interval and decarbonization (200-520 deg C) with Rb2OxLu2O3 formation

  7. 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

  8. 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

  9. Metabolism-Induced CaCO3 Biomineralization During Reactive Transport in a Micromodel: Implications for Porosity Alteration.

    Science.gov (United States)

    Singh, Rajveer; Yoon, Hongkyu; Sanford, Robert A; Katz, Lynn; Fouke, Bruce W; Werth, Charles J

    2015-10-20

    The ability of Pseudomonas stutzeri strain DCP-Ps1 to drive CaCO3 biomineralization has been investigated in a microfluidic flowcell (i.e., micromodel) that simulates subsurface porous media. Results indicate that CaCO3 precipitation occurs during NO3(-) reduction with a maximum saturation index (SIcalcite) of ∼1.56, but not when NO3(-) was removed, inactive biomass remained, and pH and alkalinity were adjusted to SIcalcite ∼ 1.56. CaCO3 precipitation was promoted by metabolically active cultures of strain DCP-Ps1, which at similar values of SIcalcite, have a more negative surface charge than inactive strain DCP-Ps1. A two-stage NO3(-) reduction (NO3(-) → NO2(-) → N2) pore-scale reactive transport model was used to evaluate denitrification kinetics, which was observed in the micromodel as upper (NO3(-) reduction) and lower (NO2(-) reduction) horizontal zones of biomass growth with CaCO3 precipitation exclusively in the lower zone. Model results are consistent with two biomass growth regions and indicate that precipitation occurred in the lower zone because the largest increase in pH and alkalinity is associated with NO2(-) reduction. CaCO3 precipitates typically occupied the entire vertical depth of pores and impacted porosity, permeability, and flow. This study provides a framework for incorporating microbial activity in biogeochemistry models, which often base biomineralization only on SI (caused by biotic or abiotic reactions) and, thereby, underpredict the extent of this complex process. These results have wide-ranging implications for understanding reactive transport in relevance to groundwater remediation, CO2 sequestration, and enhanced oil recovery. PMID:26348257

  10. 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

  11. 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.

  12. 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%.

  13. 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.

  14. 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

  15. 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

  16. Biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyalkanoates) by recombinant Escherichia coli from glucose.

    Science.gov (United States)

    Hokamura, Ayaka; Wakida, Izumi; Miyahara, Yuki; Tsuge, Takeharu; Shiratsuchi, Hideki; Tanaka, Kenji; Matsusaki, Hiromi

    2015-09-01

    The polyhydroxyalkanoate (PHA) copolymers consisting of short-chain-length (scl) and medium-chain-length (mcl) monomers have various properties ranging from stiff to flexible depending on the molar fraction of the monomer compositions. It has been reported that PhaG, which is first known as a (R)-3-hydroxyacyl-acyl carrier protein (ACP)-CoA transferase, actually functions as a 3-hydroxyacyl-ACP thioesterase, and the product of PP0763 gene from Pseudomonas putida KT2440 has a (R)-3-hydroxyacyl (3HA)-CoA ligase activity (Wang et al., Appl. Environ. Microbiol., 78, 519-527, 2012). In this study, we found a new (R)-3HA-CoA ligase (the product of PA3924 gene) from Pseudomonas aeruginosa PAO. The PA3924 gene was coexpressed with PHA synthase 1 gene (phaC1Ps) and phaGPs gene from Pseudomonas sp. 61-3, and β-ketothiolase gene (phbARe) and acetoacetyl-CoA reductase gene (phbBRe) from Ralstonia eutropha in Escherichia coli LS5218 at 25°C. As a result, the copolymer containing 94.6 mol% 3-hydroxybutyrate (3HB) and 5.4 mol% mcl-3-hydroxyalkanoates (3HA) consisting of C8, C10, C12 and C14 was synthesized by recombinant E. coli LS5218 from glucose as the sole carbon source. The concentration of P(3HB-co-3HA) (scl-co-mcl-PHA) synthesized by the recombinant E. coli LS5218 harboring phaC1Ps, phaGPs, phbABRe and the PA3924 genes was approximately 7-fold higher than that of the recombinant LS5218 harboring phaC1Ps, phaGPs, phbABRe and the PP0763 genes. The number-average molecular weight of the P(3HB-co-5.4% 3HA) copolymer was 233 × 10(3), which was relatively high molecular weight. In addition, the physical and the mechanical properties of the copolymer were demonstrated to improve the brittleness of P(3HB) homopolymer. PMID:25732207

  17. 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

  18. Doping nano-Co3O4 surface with bigger nanosized Ag and its photocatalytic properties for visible light photodegradation of organic dyes

    International Nuclear Information System (INIS)

    Highlights: • Bigger Co3O4 nanoflake was fabricated with a traditional hydrothermal method. • The Co3O4 nanoflake surface doped with nanosized Ag by a simple silver-mirror reaction. • The bigger Ag particles (>10 nm) also enhanced the catalytic activity of Co3O4. - Abstract: This paper reports the synthesis of nanosized Ag/Co3O4 composite catalysts using a silver-mirror reaction and the calibration of their catalytic activities towards methyl blue (MB) dye degradation with peroxymonosulfate (PMS) under visible light. The nanosized Ag/Co3O4 composites were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–vis spectroscopy. The experimental evidence indicated that the hydrothermal synthesis approach lead to the exposure of the {1 1 2} facets of the Co3O4 nanoflakes. Compared to Co3O4 nanoflakes, Co3O4 doped with Ag nanoparticle (average diameters of 10–15 nm) presented lower band gap energy and photoluminescent (PL) intensity. Meanwhile, the Ag/Co3O4 exhibited high stability and excellent dispersion property in dye solution. Experimental data suggested that 3.06 wt% Ag nanoparticle-doped Ag/Co3O4 nanocomposite catalyst possessed the highest catalytic activity towards MB degradation in aqueous solution at the tested concentration level of 15 mg/L, about 2.4 times higher than that of pure Co3O4. Complete decolorization of the 15 mg/L MB solution can be achieved by 3.06 wt% Ag-doped Ag/Co3O4 nanocomposite within 20 min of visible light irradiation

  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. 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.

  1. Na2CO3―induced Gas Evolution Reaction and Morphology Modulation on Magnesium Alloy during Micro―arc Oxidation

    Directory of Open Access Journals (Sweden)

    WANG Xiao-Bo, TIAN Xiu-Bo, GONG Chun-Zhi, YANG Shi-Qin

    2011-07-01

    Full Text Available Surface morphology of the ceramic coatings can be modulated by gas evolution on anodes during micro arc oxidation (MAO) processes. A novel technique to enhance gas evolution using Na2CO3―containing solution was proposed. MAO ceramic coatings were fabricated on AZ31 magnesium alloy using Na2CO3 as a special additive in Na3PO4+KOH +NaF base electrolyte. The effects of Na2CO3 addition on the reaction of gas evolution near the anode, morphology modulation and chemical composition were investigated by using GC―MS, SEM, XRD and FTIR, respectively. The results show that both O2 and CO2 are evolved from the anode with Na2CO3 addition during MAO process. MgCO3 is found in the coating during the anodic oxidation before MAO, while only MgO is detected in the coating after MAO process. It is attributed to the decomposition of MgCO3 to MgO and CO2 due to local high temperature. Na2CO3 addition has slight effect on the microstructure of the coating and MgO is the main phase no matter whether Na2CO3 is utilized. With the addition of Na2CO3 the number of larger―size pores decreases and porosity in the coatings increases.

  2. 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)

  3. In situ synthesis of Co3O4/graphene nanocomposite material for lithium-ion batteries and supercapacitors with high capacity and supercapacitance

    International Nuclear Information System (INIS)

    Highlights: → In situ solution-based preparation of Co3O4/graphene composite material. → Well dispersed Co3O4 nanoparticles on graphene nanosheets. → Co3O4/graphene exhibits highly reversible lithium storage capacity. → Co3O4/graphene delivers superior supercapacitance up to 478 F g-1. → Functional groups make contributions to the overall supercapacitance. - Abstract: Co3O4/graphene nanocomposite material was prepared by an in situ solution-based method under reflux conditions. In this reaction progress, Co2+ salts were converted to Co3O4 nanoparticles which were simultaneously inserted into the graphene layers, upon the reduction of graphite oxide to graphene. The prepared material consists of uniform Co3O4 nanoparticles (15-25 nm), which are well dispersed on the surfaces of graphene nanosheets. This has been confirmed through observations by field emission scanning electron microscopy, transmission electron microscopy and atomic force microscopy. The prepared composite material exhibits an initial reversible lithium storage capacity of 722 mAh g-1 in lithium-ion cells and a specific supercapacitance of 478 F g-1 in 2 M KOH electrolyte for supercapacitors, which were higher than that of the previously reported pure graphene nanosheets and Co3O4 nanoparticles. Co3O4/graphene nanocomposite material demonstrated an excellent electrochemical performance as an anode material for reversible lithium storage in lithium ion cells and as an electrode material in supercapacitors.

  4. TiO2 decorated Co3O4 acicular nanotube arrays and its application as a non-enzymatic glucose sensor.

    Science.gov (United States)

    Gao, Zhenfei; Zhang, Liqiang; Ma, Chi; Zhou, Qidong; Tang, Yushu; Tu, Zhiqiang; Yang, Wang; Cui, Lishan; Li, Yongfeng

    2016-06-15

    TiO2 modified Co3O4 acicular nanotube arrays (ANTAs) have been fabricated in this study, showing a good performance in glucose detection. In the experiment, the precursor Co(CO3)0.5(OH)·0.11H2O acicular nanowire arrays (ANWAs) was first grown on the fluorine doped tin oxide (FTO) substrate by a hydrothermal method. Thereafter, the uniform pink precursor Co(CO3)0.5(OH)·0.11H2O ANWAs was completely converted to the black Co3O4 ANTAs thin film by alkaline treatment. After the decoration of TiO2, the TiO2/Co3O4 ANTAs electrode exhibits a much higher current response to glucose compared with the Co3O4 ANTAs. Importantly, this neotype composite structure of Co3O4 enhances the glucose sensing performance by increasing specific surface area, additional reactive sites and synergistic effect, which make the TiO2/Co3O4 glucose sensor show a high sensitivity of 2008.82μAmM(-1)cm(-2), a fast response time (less than 5s) and a detection limit as low as 0.3396μM (S/N=3). The TiO2/Co3O4 ANTAs modified electrode exhibits a high selectivity for glucose in human serum, against ascorbic acid and uric acid. PMID:26890826

  5. 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

  6. 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.

  7. 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.)

  8. 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.

  9. 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.

  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. 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.

  12. 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.

  13. 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.

  14. Preparation and Characterization of Anadara Granosa Shells and CaCO3 as Heterogeneous Catalyst for Biodiesel Production

    Directory of Open Access Journals (Sweden)

    Hadiyanto Hadiyanto

    2016-03-01

    Full Text Available Nowadays, the use of homogenous catalyst has been gradually reduced for its operational reason. The homogenous catalyst leads in difficulty of separation after the process completed and the life cycle is shorter. Therefore, most of researches are introducing heterogenous catalyst for its substitution. This research was aimed to evaluate the use of shell of Anadara granosa and CaCO3 as source of CaO based catalyst through impregnation method. The preparation of the catalyst was started by decomposition of shells and CaCO3 at temperature of 800 oC for 3 hours, followed by impregnation at 70 oC for 4 hours and then calcined at 800 oC for 2 hours. The CaCO3 based catalyst gained high yield of biodiesel (94% as compared to Anadara granoasa based catalyst (92%. The reusability study showed that these catalysts could be used until three times recycle with 40-60% yield of biodiesel. The CaO contents of catalyst decreased up to 90% after three times recycles. Copyright © 2016 BCREC GROUP. All rights reserved Received: 10th November 2015; Revised: 6th January 2016; Accepted: 6th January 2016 How to Cite: Hadiyanto, H., Lestari, S.P., Widayat, W. (2016. Preparation and Characterization of Anadara Granosa Shells and CaCO3 as Heterogeneous Catalyst for Biodiesel Production. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (1: 21-26. (doi:10.9767/bcrec.11.1.402.21-26 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.1.402.21-26

  15. 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.

  16. A sea anemone-like CuO/Co3O4 composite: an effective catalyst for electrochemical water splitting.

    Science.gov (United States)

    Li, Xiumin; Guan, Guoqing; Du, Xiao; Cao, Ji; Hao, Xiaogang; Ma, Xuli; Jagadale, Ajay D; Abudula, Abuliti

    2015-10-18

    A facile unipolar pulse electrodeposition combined with the thermal oxidation method was applied for fabrication of CuO/Co3O4 composites on carbon electrode for water electrolysis, and it was found that the sea anemone-like one with a 3D hierarchical structure formed at -0.8 V exhibited excellent performance for water electrolysis at a low overpotential with high stability. PMID:26311303

  17. 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

  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. 99mTc(CO)3-tosufloxacin dithiocarbamate complexation and radiobiological evaluation in male Wister rat model

    International Nuclear Information System (INIS)

    In the current investigation tosufloxacin (TSN) was derivatized to its dithiocarbamate (TSND) derivative and its radiolabeling with technetium-99m using [99mTc(CO)3(H2O)3]+ precursor. The labeled TSND (99mTc(CO)3-TSND) was radiochemically characterized in saline and serum and biologically its in vitro binding with Proteus mirabilis (P. mirabilis) and biodistribution in male Wister rats (MWR) artificially infected with live and heat killed P. mirabilis. Radiochemically a stable radio-tricarbonyl TSND complex was observed with a maximum stability of 98.15 ± 0.32% and it remained more than 90% up to 4 h after reconstitution. The stability decreased to 91.00 ± 0.30% from 98.15 ± 0.32% within 4 h. In serum at 37 deg C the growth of some unwanted side product decreased the stability by 15.65% within 16 h. The complex showed saturated in vitro binding with P. mirabilis up to 78.50% (90 min). In MWR infected with live P. mirabilis the percent (%) uptake of the complex in blood, liver, spleen, stomach, intestines and kidneys were almost similar to the MWR infected with heat killed. However, the % accumulation of the complex in the infected muscle was six times higher than in the inflamed and normal muscle in MWR infected with live P. mirabilis. On the basis of immovability of the 99mTc(CO)3-TSND complex in normal saline, in vitro permanence in serum, saturated in vitro binding with P. mirabilis and six fold uptake in the infected muscle of the MWR infected with live P. mirabilis as compared to the normal muscle, the suitability of the 99mTc(CO)3-TSND complex is established as a promising infection radiotracer. (author)

  1. Effect of Precursor Synthesis on Catalytic Activity of Co3O4 in N2O Decomposition.

    Czech Academy of Sciences Publication Activity Database

    Chromčáková, Ž.; Obalová, L.; Kovanda, F.; Legut, D.; Titov, A.; Ritz, M.; Fridrichová, D.; Michalik, S.; Kustrowski, P.; Jirátová, Květa

    2015-01-01

    Roč. 257, Part 1 (2015), s. 18-25. ISSN 0920-5861. [AWPAC2014 - International Symposium on Air & Water Pollution Abatement Catalysis. Krakow, 01.09.2014-05.09.2014] R&D Projects: GA ČR GA14-13750S Institutional support: RVO:67985858 Keywords : cobalt spinel * Co3O4 * N2O decomposition * precursor synthesis Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 3.893, year: 2014

  2. 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

  3. 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...

  4. 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...

  5. Effects of Low Dissolved-Oxygen Concentrations on Poly-(3-Hydroxybutyrate-co-3-Hydroxyvalerate) Production by Alcaligenes eutrophus

    OpenAIRE

    Lefebvre, G.; Rocher, M.; Braunegg, G.

    1997-01-01

    The bacterial copolyester poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) was produced with Alcaligenes eutrophus DSM 545 from glucose and sodium propionate in a fed-batch fermentation with both nitrogen limitation and low dissolved-oxygen concentrations. When the dissolved-oxygen content was kept between 1 and 4% of air saturation during the polymer accumulation phase, the yield of 3-hydroxybutyrate (3HB) monomer from glucose was not affected, but the propionate-to-3-hydroxyvalerate (3HV) mono...

  6. Sensing Properties of Pd-Loaded Co3O4 Film for a ppb-Level NO Gas Sensor

    Directory of Open Access Journals (Sweden)

    Takafumi Akamatsu

    2015-04-01

    Full Text Available We prepared 0.1 wt%–30 wt% Pd-loaded Co3O4 by a colloidal mixing method and investigated the sensing properties of a Pd-loaded Co3O4 sensor element, such as the sensor response, 90% response time, 90% recovery time, and signal-to-noise (S/N ratio, toward low nitric oxide (NO gas levels in the range from 50 to 200 parts per billion. The structural properties of the Pd-loaded Co3O4 powder were investigated using X-ray diffraction analysis and transmission electron microscopy. Pd in the powder existed as PdO. The sensor elements with 0.1 wt%–10 wt% Pd content have higher sensor properties than those without any Pd content. The response of the sensor element with a 30 wt% Pd content decreased markedly because of the aggregation and poor dispersibility of the PdO particles. High sensor response and S/N ratio toward the NO gas were achieved when a sensor element with 10 wt% Pd content was used.

  7. 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.

  8. 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.

  9. Spin state of Co3+ in LaCo1-xRhxO3 investigated by structural phenomena

    International Nuclear Information System (INIS)

    Neutron diffraction for a polycrystalline sample of LaCo0.8Rh0.2O3 and synchrotron x-ray diffraction for polycrystalline samples of LaCo0.9Rh0.1O3 and LaCo0.8Rh0.2O3 have been carried out in order to investigate the structural properties related with the spin state of Co3+ ions. We have found that the Co(Rh)-O bond lengths in the Co(Rh)O6 octahedron of LaCo0.8Rh0.2O3 are nearly identical at 10 K. The lattice volume for the Rh3+ substituted samples decreases with the thermal expansion coefficient similar to that of LaCoO3 from room temperature, and ceases to decrease around 70 K. These experimental results favor a mixed state consisting of the high-spin-state and low-spin-state Co3+ ions, and suggest that there are thermally excited high-spin-state Co3+ ions in addition to those pinned by the substituted Rh3+ ions. (author)

  10. Effects of Ni substitution on the properties of Co3O4/graphite composites as anode of lithium ion batteries

    International Nuclear Information System (INIS)

    Ni-substituted Co3O4/graphite composites were synthesized by precipitation of cobalt oxalate and nickel oxalate on the surface of graphite and pyrolysis of the precipitate. The effects of nickel content and calcination temperature on the properties of the composites were investigated. The samples were characterized by thermogravimetry and differential thermal analysis (TG/DTA), X-ray diffraction (XRD), scanning electron microscope (SEM), cyclic voltammetry (CV) and charge/discharge measurements. The composites consist of graphite and a face-centered cubic (fcc) Co3O4 phase of fd3m space group, and there is no diffraction peaks associated with nickel compounds. Mild nickel substitution can improve the reversible capacity of the Co3O4/graphite composite. With increasing the calcination temperature from 300 to 500 deg. C, the reversible capacity of the composites with 10% Ni substitution increases from 641 to 874 mA h g-1. The composite synthesized at 400 deg. C shows an initial reversible capacity of 690 mA h g-1 and excellent cycling stability.

  11. [99mTc(CO)3]+ labeled histidine derivative containing 4-nitroimidazole : Synthesis, biodistribution as a tumor hypoxia imaging agent

    International Nuclear Information System (INIS)

    A novel histidine derivative containing 4-nitroimidazole, (S)-2-(4-((4-nitro-1H-imidazol-1-yl) methyl) benzamido)-3-(1H-imidazol-4-yl)propanoic acid (His-NI), was synthesized and labeled with [99mTc(CO)3(H2O)3]+. The tricarbonyl technetium complex, the 99mTc(CO)3-His-NI, showed a 99% yield under mild conditions at a low His-NI ligand concentration of 10-4 mol·L-1, and its biodistribution in mice bearing S180 tumor had a selective accumulation in tumor (2.01±0.40% ID/g at 1 h postinjection) and a slow clearance. The tumor/muscle ratio was 1.64 at 1 h, 3.10 at 4 h, and 3.88 at 24 h,indicating that the 99mTc(CO)3-His-NI has a potential to image tumor hypoxia. (authors)

  12. Facile Synthesis of Histidine Derivatives for fac-[M(CO)3]+ precursor [M=99mTc, 188Re

    International Nuclear Information System (INIS)

    The technetium-99m(99mTc) is one of the most widely used radionuclides in nuclear medicine, because of its preferable properties(T1/2= 6.02 hr, Eγ= 140 keV). More than 85% of diagnostic scans were performed in hospitals worldwide. A variety of 99mTc-based radiopharmaceuticals have been developed for evaluating organ function and assessing disease status by imaging methods. The labeling of biologically active molecules with 99mTc is the most important research area. Although 99mTc complexes with a +5-oxidation state are commonly available recently, many researches have been focused on the 99mTc precursor with the +1-oxidation state [M(CO)3]+ due to its small size and ease in preparation. A variety of researches have revealed that histidine complexes with the fac-[M(CO)3] precursor show a good stability through in-vivo and in-vitro studies. In this study, we present a synthetic approach for the histidine derivatives as bifunctional chelating agent for the conjugation with biomolecules as well as for a labeling with the fac-[M(CO)3]+ precursor [M=99mTc, 186/188Re

  13. 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

  14. 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.

  15. Synergistic Cocatalytic Effect of Carbon Nanodots and Co3 O4 Nanoclusters for the Photoelectrochemical Water Oxidation on Hematite.

    Science.gov (United States)

    Zhang, Peng; Wang, Tuo; Chang, Xiaoxia; Zhang, Lei; Gong, Jinlong

    2016-05-01

    Cocatalysis plays an important role in enhancing the activity of semiconductor photocatalysts for solar water splitting. Compared to a single cocatalyst configuration, a cocatalytic system consisting of multiple components with different functions may realize outstanding enhancement through their interactions, yet limited research has been reported. Herein we describe the synergistic cocatalytic effect between carbon nanodots (CDots) and Co3 O4 , which promotes the photoelectrochemical water oxidation activity of the Fe2 O3 photoanode with a 60 mV cathodically shifted onset potential. The C/Co3 O4 -Fe2 O3 photoanode exhibits a photocurrent density of 1.48 mA cm(-2) at 1.23 V (vs. reversible hydrogen electrode), 78 % higher than that of the bare Fe2 O3 photoanode. The slow reaction process on the single Co(III) -OH site of the Co3 O4 cocatalyst, oxidizing H2 O to H2 O2 with two photogenerated holes, could be accelerated by the timely H2 O2 oxidation to O2 catalyzed on CDots. PMID:27011264

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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)

  1. 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.

  2. 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

  3. Effect of Co3O4 and CeO2 Infiltration on the Activity of a LSM15/GDC10 Highly Porous Electrochemical Reactor

    DEFF Research Database (Denmark)

    Ippolito, Davide; Kammer Hansen, Kent

    2014-01-01

    VOC component of Diesel engine exhausts, over a wide range of temperatures. The entire reactor was thought as a highly porous catalytic filter for a possible application in a Diesel exhausts purification system. The porous reactor was used as a backbone for the infiltration of Co3O4 and Co3O4/CeO2...

  4. Interfacial effect of the nanostructured Ag2S/Co3O4 and its catalytic mechanism for the dye photodegradation under visible light

    Science.gov (United States)

    Qiu, X. P.; Yu, J. S.; Xu, H. M.; Chen, W. X.; Hu, W.; Bai, H. Y.; Chen, G. L.

    2016-01-01

    In this study, the synthesis of a highly hybrid, heterogeneously structured nanocomposite catalyst consisting of Ag2S nanoparticles dotted on a Co3O4 microrod array is reported. The average diameter and length of the Co3O4 microrods was optimized to be approximately 300 nm and 20 μm, respectively, and the average size of the Ag2S nanoparticles was approximately 10 nm. When the Ag2S nanoparticles were deposited on the Co3O4 microrods, the characteristic optical band gap energy of Co3O4 decreased from 1.26 eV to 1.23 eV, and the intensity of the absorbance peak at 650 nm increased significantly. The catalytic activity of nanosized Ag2S/Co3O4 for the photodegradation of organic contaminants with potassium hydrogen persulfate (PMS) or ozone (O3) was evaluated using basic green 1 dye (BG1) as a model pollutant. In the presence of the hybrid Ag2S/Co3O4 catalyst developed in this study, the complete photodegradation of the BG1 solution was achieved in 20 min and 6 min when PMS and O3 were used, respectively. In addition, the experimental results suggest that the catalytic photodegradation of BG1 using the Ag2S/Co3O4/PMS and Ag2S/Co3O4/O3 processes was dominated by the rad OH and rad O2- radicals, respectively.

  5. First-principles investigation of electronic, mechanical and thermodynamic properties of L12 ordered Co3(M, W) (M = Al, Ge, Ga) phases

    International Nuclear Information System (INIS)

    Studies were carried out on the equilibrium structural, temperature-dependent mechanical and thermodynamic properties of the Co3(M, W) (M = Al, Ge, Ga) phases in terms of first-principles calculations. The results of the ground-state elastic constants revealed that Co3(M, W) phases are mechanically stable and possess intrinsic ductility. It was found that the elastic heat-resistant properties of Co3(Ge, W) phase are inferior to those of Co3(Al, W) and Co3(Ga, W). Analyzing the charge density difference provides the explanation that the sharp decrease in mechanical properties is mainly due to the weakening of Co–Ge bonding at elevated temperatures for Co3(Ge, W). The elastic anisotropy as a function of temperature is discussed using a universal index. It is observed that Co3(M, W) phases show a high degree of elastic anisotropy. The degree of elastic anisotropy could be significantly decreased by an increase in temperature for Co3(M, W). The lattice vibration is treated with the quasiharmonic phonon approach, considering both the vibrational and thermal electronic contributions. The thermodynamic properties as a function of temperature are computed without any adjustable parameters, including heat capacity, entropy, enthalpy and thermal expansion coefficient

  6. Fabrication of a novel heterostructure of Co3O4-modified TiO2 nanorod arrays and its enhanced photoelectrochemical property

    International Nuclear Information System (INIS)

    Highlights: ► We developed a facile route for the fabrication of Co3O4 -modified TiO2 NRs. ► The Co3O4-modified TiO2 NRs obviously increase the visible light absorption. ► The superior photoelectrochemical activity is achieved on the Co3O4-modified TiO2 NR. - Abstract: A novel heterostructure of Co3O4-modified TiO2 nanorod arrays (NRs) is fabricated by a facile two-step solution-based method. First, TiO2 NRs grow on fluorine-doped tin oxide (FTO) conductive glass substrates by hydrothermal method. Afterward, Co3O4 nanoparticles were coated on the TiO2 NRs using a photochemical coating method. The samples were characterized by X-ray diffraction, field emission electron-scanning microscopy, transmission electron microscopic, X-ray photoelectron spectroscopy and UV–visible spectroscopy. For the first time, the photoelectrochemical (PEC) properties of the electrode made by the Co3O4-modified TiO2 NRs were investigated under visible-light irradiation. The results showed remarkably enhanced visible light PEC response of the Co3O4-modified TiO2 NRs in comparison with the pure TiO2 NRs, offering attractive perspectives for applications of the Co3O4-modified TiO2 NRs in solar cells or photocatalysts.

  7. Different synthesis protocols for Co3O4 -CeO2 catalysts--part 1: influence on the morphology on the nanoscale.

    Science.gov (United States)

    Yang, Jingxia; Lukashuk, Liliana; Akbarzadeh, Johanna; Stöger-Pollach, Michael; Peterlik, Herwig; Föttinger, Karin; Rupprechter, Günther; Schubert, Ulrich

    2015-01-01

    Co3 O4 -modified CeO2 (Co/Ce 1:4) was prepared by a combination of sol-gel processing and solvothermal treatment. The distribution of Co was controlled by means of the synthesis protocol to yield three different morphologies, namely, Co3 O4 nanoparticles located on the surface of CeO2 particles, coexistent Co3 O4 and CeO2 nanoparticles, or Co oxide structures homogeneously distributed within CeO2 . The effect of the different morphologies on the properties of Co3 O4 -CeO2 was investigated with regard to the crystallite phase(s), particle size, surface area, and catalytic activity for CO oxidation. The material with Co3 O4 nanoparticles finely dispersed on the surface of CeO2 particles had the highest catalytic activity. PMID:25384333

  8. Facile synthesis of ultrafine Co3O4 nanocrystals embedded carbon matrices with specific skeletal structures as efficient non-enzymatic glucose sensors.

    Science.gov (United States)

    Li, Mian; Han, Ce; Zhang, Yufan; Bo, Xiangjie; Guo, Liping

    2015-02-25

    A facile, effective, and environmentally friendly method has been adopted for the first time to prepare tiny Co3O4 nanocrystals embedded carbon matrices without using surfactants, harmful organic reagents or extreme conditions. Structural characterizations reveal that the size-controlled Co3O4 nanocrystals are uniformly dispersed on carbon matrices. Electrochemical measurements reveal that Co3O4-ordered mesoporous carbon (OMC) can more efficiently catalyze glucose oxidation and acquire better detection parameters compared with those for the Co3O4-macroporous carbon, Co3O4-reduced graphene oxide, and free Co3O4 nanoparticles (NPs) (such as: the large sensitivity (2597.5 μA cm(-2) mM(-1) between 0 and 0.8 mM and 955.9 μA cm(-2) mM(-1) between 0.9 and 7.0 mM), fast response time, wide linear range, good stability, and surpassingly selective capability to electroactive molecules or Cl(-)). Such excellent performances are attributed to the synergistic effect of the following three factors: (1) the high catalytic sites provided by the uniformly dispersed and size-controlled Co3O4 nanocrystals embedded on OMC; (2) the excellent reactant transport efficiency caused by the abundant mesoporous structures of OMC matrix: (3) the improved electron transport in high electron transfer rate (confinement of the Co3O4 NPs in nanoscale spaces ensured intimate contact between Co3O4 nanocrystals and the conducting OMC matrix). The superior catalytic activity and selectivity make Co3O4-OMC very promising for application in direct detection of glucose. PMID:25702271

  9. 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.

  10. 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.

  11. 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 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. PMID:24731158

  12. 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.

  13. 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

  14. A critical quantum chemical and experimental study of the potentiality of direct labeling of the CN group with [99mTc(CO)3]+ or [186/188Re(CO)3]+ in CN containing biomolecules

    International Nuclear Information System (INIS)

    Introduction: It was determined recently that [99mTc(OH2)2(X-)(CO3)3] could strongly bind to the CN group, allowing direct labeling of CN in vitamin B12 despite the presence of a benzimidazole group. The aim of this paper was to perform a critical study of this potentiality, coupling quantum chemical calculations to experimental evidence. Methods: Computational methods: Within the density functional theory calculations, the 6-31+G** basis set (C, H, O, N atoms) and the LANL2DZ basis set (Tc,Re) were used. Stability calculations of the [RCNM(CO)3]+) (M=Tc,Re) complexes were performed with the Gaussian 03 suite of programs, while for the evaluation of relative stability substitution reactions were used. Radiochemistry: Vitamin B12, 4-hydroxy-benzylcyanide and 4-methoxy-benzonitrile were labeled at 100 deg. C during 30 min. High-performance liquid chromatography analysis was performed using radioactive and UV detection. Results: Computational methods: The influence of different ligands on the stability yielded a sequence: imidazole>tBuCN>NH3∼CH3CN>HCN (mimicking the best CoCN)>H2O. The transmetalation reaction indicates that all ligands prefer Re to Tc. The preference for the nitrogen atom of imidazole to the cyanide nitrogen atom for complex formation with [Tc(CO)3(H2O)3]+ is interpreted in terms of the hard and soft acid and base properties principle. Radiochemistry: 4-Hydroxy-benzylcyanide and 4-methoxy-benzonitrile did not show any labeling. An excess of acetonitrile did not inhibit the labeling of vitamin B12 as expected if the CN group should be involved, indicating that the labeling occurs on a stronger complexing group present like benzimidazole. Conclusion: Both theory and experiments prove that [CN-Tc(CO)3(H2O)(2-x)Lx]+ complexes are weak and that in vitamin B12 most probably the benzimidazole group is involved

  15. New 99mTc(CO)3(NNO) complexes in the development of 5-HT1A receptor imaging agents

    International Nuclear Information System (INIS)

    In this work we report the synthesis, characterization and biological evaluation of two new neutral tricarbonyl fac-M(CO)3(NNO) (M=Re, 99mTc) derivatives of WAY-100635 as potential 99mTc agents for the in vivo imaging of 5-HT1A receptors. The new pharmacophore NNO ligands are based on the picolylamine N,N-diacetic acid (PADA) ligand and their synthesis was achieved through the PADA anhydride, showing thus the applicability of this synthetic approach, developed in our laboratory, for the incorporation of bioactive amines in the PADA molecule and the development of target specific radiopharmaceuticals. The rhenium complexes were synthesized using [NEt4]2[Re(CO)3Br3] as a precursor and fully characterized by elemental analysis and spectroscopic methods. The analogous technetium-99m complexes were also prepared quantitatively using the [99mTc(CO)3(H2O)3]+ precursor and their structure corroborated by means of the rhenium complexes. The lipophilicity of the Tc complexes is in the range normally accepted for substances to be able to cross the BBB. Competition binding tests showed moderate affinity for the 5-HT1A receptors, with IC50 values at the nanomolar range (30 and 116 nM). Biodistribution in healthy animals was characterized by high initial blood and liver uptake and fast blood and tissue depuration with excretion taking place mainly through the hepatobiliary system. None of the new complexes showed any significant brain uptake, suggesting that the ability of a compound to cross the BBB is determined by more factors than charge, lipophilicity and size. (orig.)

  16. Core-double shell ZnO/ZnS@Co3O4 heterostructure as high performance pseudocapacitor.

    Science.gov (United States)

    Sarkar, Sanjit; Maiti, Sandipan; Mahanty, Sourindra; Basak, Durga

    2016-05-31

    In recent times, a great deal of attention has been paid to the balanced design and fabrication of core-shell heterostructures for enhanced pseudocapacitor (SC) performance. In this paper, we report the synthesis of ZnO@Co3O4 based core-shell heterostructures with controllable shell thickness for the first time by a simple low-temperature solution-based method and their detailed electrode performance as SC wherein a highly enhanced pseudocapacitance of 296 C g(-1) at a current density of 0.5 A g(-1) has been observed. Further, modifying the surface of ZnO by its sulfur analogue (i.e., by creating a ZnO/ZnS heterostructure), an improved capacitance of 317 C g(-1) at a current density of 0.5 A g(-1) for ZnO/ZnS@Co3O4 has been obtained along with a better rate performance. This is attributed to an efficient charge transfer from ZnS to ZnO. Impressively, the core-double shell heterostructure exhibits high energy density of 36 Wh kg(-1) at a power density of 204.3 W kg(-1). Even at a very high power density of 10.9 kW kg(-1), it shows an energy density of 14.7 Wh kg(-1). To the best of our knowledge, this is the first study of the electrochemical properties of ZnO/ZnS@Co3O4 heterostructure. PMID:27163693

  17. 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.

  18. 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 ...

  19. 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...

  20. Study On Preparation Of Nano-CaCO3 From Vietnam Limestone By Using High Gravity Technology

    International Nuclear Information System (INIS)

    In recent years, nanosized materials have been paid much attention by a lot of scientists and producers because of their tremendous potential and applications in many fields: electronics, optics, chemistry, environment and so on. Among nano particle materials, precipitated calcium carbonate (PCC) has been widely used as fillers for papermaking, plastics, coatings and agriculture. In this project, we have researched a novel method named high gravity reactive precipitation (HGRP) to prepare nano-CaCO3 which has average size about 70 nm from limestone ore in Yen Bai province by using gas-liquid-solid reaction system. This project also describes principles of the method, parameters of apparatus and experimental conditions. (author)