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Sample records for sampling ta cvs

  1. 40 CFR 90.424 - Dilute sampling procedures-CVS calibration.

    Science.gov (United States)

    2010-07-01

    ... calibration. 90.424 Section 90.424 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... “true” value) for the CVS calibration. (Note: In no case should an upstream screen or other restriction... Parameter Symbol Units Sensor-readout tolerances Barometric pressure (corrected) PB kPa ±.340 kPa. Ambient...

  2. 40 CFR 91.424 - Dilute sampling procedure-CVS calibration.

    Science.gov (United States)

    2010-07-01

    ... radius or American Society of Mechanical Engineers (ASME) flow nozzles are considered equivalent if..., kPa (inches fluid). (iv) A linear least squares fit is performed to generate the calibration... density of exhaust hydrocarbons. (5) The gravimetric mass is subtracted from the CVS measured mass and...

  3. 40 CFR 89.421 - Exhaust gas analytical system; CVS bag sample.

    Science.gov (United States)

    2010-07-01

    ... the measurement of carbon monoxide and carbon dioxide, and a chemiluminescence detector (CLD) (or HCLD... following requirements: (1) The CLD (or HCLD) requires that the nitrogen dioxide present in the sample be...

  4. 40 CFR 91.423 - Exhaust gas analytical system; CVS grab sample.

    Science.gov (United States)

    2010-07-01

    ... carbon dioxide, and a chemiluminescence detector (CLD) (or heated CLD (HCLD)) for the measurement of...) The CLD (or HCLD) requires that the nitrogen dioxide present in the sample be converted to nitric...

  5. 40 CFR 90.423 - Exhaust gas analytical system; CVS grab sample.

    Science.gov (United States)

    2010-07-01

    ... measurement of carbon monoxide and carbon dioxide, and a chemiluminescence detector (CLD) (or heated CLD (HCLD... following requirements: (1) The CLD (or HCLD) requires that the nitrogen dioxide present in the sample be...

  6. Chorionic Villus Sampling (CVS)

    Science.gov (United States)

    ... Careers Archives Health Topics Pregnancy Before or between pregnancies Nutrition, weight & fitness Prenatal care Is it safe? Labor & ... Report Cards Careers Archives Pregnancy Before or between pregnancies Nutrition, weight & fitness Prenatal care Is it safe? Labor & ...

  7. CVS pocket reference

    CERN Document Server

    Purdy, Gregor N

    2003-01-01

    The beauty of open source is making code freely available. The curse is trying to organize the chaos that code development can evolve into. CVS, the Concurrent Version System, is an open source tool for managing and distributing source code. It allows multiple users dispersed over a wide geographic area to work on the same file at the same time, using a shared directory. Under CVS, multiple users can check out files from a directory tree, make changes, and then commit those changes back into the directory. CVS is a pivotal tool on many projects involving information or software, whether in-ho

  8. Sampling and analysis plan for assessment of beryllium in soils surrounding TA-40 building 15

    Energy Technology Data Exchange (ETDEWEB)

    Ruedig, Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-12-19

    Technical Area (TA) 40 Building 15 (40-15) is an active firing site at Los Alamos National Laboratory. The weapons facility operations (WFO) group plans to build an enclosure over the site in 2017, so that test shots may be conducted year-round. The enclosure project is described in PRID 16P-0209. 40-15 is listed on LANL OSH-ISH’s beryllium inventory, which reflects the potential for beryllium in/on soils and building surfaces at 40-15. Some areas in and around 40-15 have previously been sampled for beryllium, but past sampling efforts did not achieve complete spatial coverage of the area. This Sampling and Analysis Plan (SAP) investigates the area surrounding 40-15 via 9 deep (≥1-ft.) soil samples and 11 shallow (6-in.) soil samples. These samples will fill the spatial data gaps for beryllium at 40-15, and will be used to support OSH-ISH’s final determination of 40-15’s beryllium registry status. This SAP has been prepared by the Environmental Health Physics program in consultation with the Industrial Hygiene program. Industrial Hygiene is the owner of LANL’s beryllium program, and will make a final determination with regard to the regulatory status of beryllium at 40-15.

  9. 46,XY,DUP(10Q) IN DIRECT CVS PREPARATION AND MOSAIC 48,XXXY,DUP(10Q) IN CVS LONG-TERM CULTURE AND FETAL TISSUE

    NARCIS (Netherlands)

    SIJMONS, RH; SIKKEMARADDATZ, B; KLOOSTERMAN, MD; BRIET, JW; DEJONG, B; LESCHOT, NJ

    Chorionic villus sampling (CVS) was performed on a 40-year-old woman at 9 1/2 menstrual weeks because of advanced maternal age. The direct preparation showed 46,XY,dup(10)(q11.2q23.2). CVS long-term culture and fetal tissue revealed a rare additional abnormality: 48,XXXY,dup(10)(q11.2q23.2). This

  10. Laboratory analysis of soil hydraulic properties of TA-49 soil samples. Volume I: Report summary

    International Nuclear Information System (INIS)

    1995-04-01

    The Hydrologic Testing Laboratory at Daniel B. Stephens ampersand Associates, Inc. (DBS ampersand A) has completed laboratory tests on TA-49 soil samples as specified by Mr. Daniel A. James and summarized in Table 1. Tables 2 through 12 give the results of the specified analyses. Raw laboratory data and graphical plots of data (where appropriate) are contained in Appendices A through K. Appendix L lists the methods used in these analyses. A detailed description of each method is available upon request. Thermal properties were calculated using methods reviewed by Campbell and covered in more detail in Appendix K. Typically, soil thermal conductivities are determined using empirical fitting parameters (five in this case), Some assumptions are also made in the equations used to reduce the raw data. In addition to the requested thermal property measurements, calculated values are also presented as the best available internal check on data quality. For both thermal conductivities and specific heats, calculated and measured values are consistent and the functions often cross. Interestingly, measured thermal conductivities tend to be higher than calculated thermal conductivities around typically encountered in situ moisture contents (±5 percent). While we do not venture an explanation of the difference, sensitivity testing of any problem requiring nonisothermal modeling across this range is in order

  11. QPOs in CVs: An executive summary

    Science.gov (United States)

    Warner, Brian; Woudt, Patrick A.

    2008-09-01

    An overview is given of the properties of the various kinds of quasi-periodic luminosity modulations observed in cataclysmic variables (CVs). The two principal types, known in the CV literature as dwarf nova oscillations and quasi-periodic oscillations, have similarities to the high and low frequency quasi-periodic oscillations in X-Ray binaries. There is a further well observed class known as longer period dwarf nova oscillations. In CVs the observed interrelations between these oscillations suggests a model of magnetically controlled accretion onto a rapidly rotating equatorial belt of accreted gas. Non-radial oscillations of the central white dwarf are observed in some systems.

  12. FAKTOR YANG BERHUBUNGAN DENGAN KELUHAN COMPUTER VISION SYNDROME (CVS PADA PEKERJA RENTAL KOMPUTER DI WILAYAH UNNES

    Directory of Open Access Journals (Sweden)

    Melati Aisyah Permana

    2015-07-01

    Full Text Available Computer as a tool that is widely used human beings, it also raises occupational diseases as well as the use of machine in industry. Vision problems caused bye the use of computers, the American Optometric Association (AOA called Computer Vision Syndrome (CVS as a compound eye problems related to employment experienced by a person at close range as or related to computer use. The purpose of this study was to analyze the relationship between the working length, the distance eye with the monitor, lighting intensity, work attitude, and identifity the incidence of complaints of CVS workers experienced computer rentals. This study used Cross Sectional approach. Number of population and sample of 36 peoples working computer rental in the area Unnes campus. The instruments used in the form of quetionnatires, meter, and Lux meter. Chi square test result : (1the working length (p=0,005; (2 the distance eye with the monitor (p=0,012; (3 lighting intensity (p=0,001; (4 work attitude (p=0,014 with complaints of CVS in workers computer rental at the campus Unnes. Suggestion for worker is to check their eyes regulary to the doctor if the complaints of CVS in order to minimize the occurrence of more severe diseases. While other researchers needed for further studies with different variables to better determine other factors associated with symptoms of Computer Vision Syndrome (CVS.

  13. Computer vision syndrome (CVS) - Thermographic Analysis

    Science.gov (United States)

    Llamosa-Rincón, L. E.; Jaime-Díaz, J. M.; Ruiz-Cardona, D. F.

    2017-01-01

    The use of computers has reported an exponential growth in the last decades, the possibility of carrying out several tasks for both professional and leisure purposes has contributed to the great acceptance by the users. The consequences and impact of uninterrupted tasks with computers screens or displays on the visual health, have grabbed researcher’s attention. When spending long periods of time in front of a computer screen, human eyes are subjected to great efforts, which in turn triggers a set of symptoms known as Computer Vision Syndrome (CVS). Most common of them are: blurred vision, visual fatigue and Dry Eye Syndrome (DES) due to unappropriate lubrication of ocular surface when blinking decreases. An experimental protocol was de-signed and implemented to perform thermographic studies on healthy human eyes during exposure to dis-plays of computers, with the main purpose of comparing the existing differences in temperature variations of healthy ocular surfaces.

  14. Do third-party plans really pay for CVS care?

    Science.gov (United States)

    Soden, Richard

    2002-04-01

    Until specific CPT and ICD-9 codes are created and approved for CVS, and until there is uniform agreement that CVS is a true medical anomaly (or not), each practitioner will have to decide on how to bill for the signs and symptoms of Computer Vision Syndrome. If the practitioner chooses to view CVS as a medical problem, then the same guidelines and rules for all other patients should be followed with appropriate documentation using CPT and ICD-9 coding. If the practitioner chooses to consider CVS solely as an optical problem, this is a "noncovered" service and the patient or any applicable optical plan will be responsible for payment. One final note: each practitioner who tests for CVS will also have to determine if there is a separate fee for CVS testing. If the practitioner considers CVS to be a medical problem, it may be applicable to include testing for Computer Vision Syndrome as an incidental test to the medical office visit. If the practitioner chooses to consider CVS to be purely an optical problem, it may be appropriate to add an appropriate charge to the noncovered examination. Whatever the decision is, there must be consistency from patient to patient.

  15. Evaluation Of Growth And Development In Mango Fruits Cvs. Julie ...

    African Journals Online (AJOL)

    Evaluation Of Growth And Development In Mango Fruits Cvs. Julie And Peter To Determine Maturity. ... Two mango cultivars viz., Julie and Peter, were studied for growth and development of fruits in 2001 and 2002 ... HOW TO USE AJOL.

  16. 40 CFR 86.1319-90 - CVS calibration.

    Science.gov (United States)

    2010-07-01

    ....1319-90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... “true” value) for the CVS calibration. (Note: In no case should an upstream screen or other restriction... Data Measurements Parameter Symbol Units Sensor-readout tolerances Barometric pressure (corrected) PB...

  17. 40 CFR 86.119-90 - CVS calibration.

    Science.gov (United States)

    2010-07-01

    ... the flow equation for a critical venturi. Gas flow is a function of inlet pressure and temperature... been obtained, verification of the entire system can be performed by injecting a known mass of gas into... CVS pump. All the parameters related to the pump are simultaneously measured with the parameters...

  18. 40 CFR 86.219-94 - CVS calibration.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false CVS calibration. 86.219-94 Section 86.219-94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty...

  19. Carbonitrides in the system Ta-TaC-TaN

    International Nuclear Information System (INIS)

    Ritzhaupt-Kleissl, H.J.

    1975-04-01

    Specimens have been prepared in the binary section TaC-TaN and the carbon-rich region of the Ta-TaC-TaN system by hot pressing and subsequent homogenisation. It was possible to prepare nitrogen-rich carbonitrides by homogenizing them at 1,800 0 C under a nitrogen-pressure of 50 at up to the composition of 70 mol% TaN/30 mol% TaC. Those carbonitrides containing less than 25 at% nitrogen could be prepared by homogenisation at 2,000 0 C under a nitrogen-pressure of 600 Torr. Subsequent ageing at temperatures of 1,200, 1,300 and 1,400 0 C in high vacuum as well as at 1 at nitrogen resulted in the appearance of precipitations of epsilon-TaN, β-Ta 2 (C,N) and of the zeta-phase. The type amount and shape of the precipitated phases are dependent on the ageing conditions and on the composition the specimens. Single phase specimens with compositions close to the non-metal deficient phase boundary as well as multi-phase carbonitrides with high nitrogen contents and very fine precipitates showed values of the Vickers-hardness up to 3,000 kp/mm 2 at room temperature. With regard to the hot hardness up to a temperature of 1,300 0 C specimens aged in high vacuum were superior to those which were only homogenized as well as to those aged under a nitrogen-pressure of 1 at. On an average the best hardness-values have been found at room temperature as well as at temperatures up to 1,300 0 C for carbonitrides consisting of 50 mol% TaC/50 mol% TaN after homogenisation and subsequent ageing for 40 h at 1,300 0 C. (orig.) [de

  20. CVs and millisecond pulsar progenitors in globular clusters

    Science.gov (United States)

    Grindlay, J. E.; Cool, A. M.; Bailyn, C. D.

    1991-01-01

    The recent discovery of a large population of millisecond pulsars in globular clusters, together with earlier studies of both low luminosity X-ray sources and LMXBs in globulars, suggest there should be significant numbers of CVs in globulars. Although they have been searched for without success in selected cluster X-ray source fields, systematic surveys are lacking and would constrain binary production and both stellar and dynamical evolution in globular clusters. We describe the beginnings of such a search, using narrow band H-alpha imaging, and the sensitivities it might achieve.

  1. Corrosion Characteristics of Ti-xTa Alloys with Ta contents

    International Nuclear Information System (INIS)

    Kim, H. J.; Choe, H. C.

    2013-01-01

    The purpose of this study was to investigate corrosion characteristics of Ti-xTa alloys with Ta contents. Ti-xTa alloys used as samples (x=30, 40%) were arc-melted under argon atmosphere of 99.9% purity. Ti-xTa alloys were homogenized for 12hr at 1000 .deg. C and then water quenched. The surface characteristics of Ti-xTa alloys were investigated using optical microscopy (OM) and X-ray diffractometer (XRD). The anodic corrosion behaviors of the specimens were examined through potentiodynamic, potentiostatic and galvanostatic test in 0.9 % NaCl solution at 36.5 ± 1 .deg. C. After corrosion test, the surface characteristics of Ti-xTa alloys were investigated using OM. The microstructure of Ti-Ta alloy showed the beta structure with Ta content. The corrosion resistance of Ti alloy was improved by increasing Ta content and the corrosion morphology of Ti-Ta alloy showed that the site attacked by chloride ion decreased from the active to passive region with Ta content. Potential of Ti-40Ta alloy increased as time increased, whereas, current density of Ti-40Ta alloy decreased as time increased compared to Ti-30 alloy

  2. Phase Velocity Estimation of a Microstrip Line in a Stoichiometric Periodically Domain-Inverted LiTaO3 Modulator Using Electro-Optic Sampling Technique

    Directory of Open Access Journals (Sweden)

    Shintaro Hisatake

    2008-01-01

    Full Text Available We estimate the phase velocity of a modulation microwave in a quasi-velocity-matched (QVM electro-optic (EO phase modulator (QVM-EOM using EO sampling which is accurate and the most reliable technique for measuring voltage waveforms at an electrode. The substrate of the measured QVM-EOM is a stoichiometric periodically domain-inverted LiTaO3 crystal. The electric field of a standing wave in a resonant microstrip line (width: 0.5 mm, height: 0.5 mm is measured by employing a CdTe crystal as an EO sensor. The wavelength of the traveling microwave at 16.0801 GHz is determined as 3.33 mm by fitting the theoretical curve to the measured electric field distribution. The phase velocity is estimated as vm=5.35×107 m/s, though there exists about 5% systematic error due to the perturbation by the EO sensor. Relative dielectric constant of εr=41.5 is led as the maximum likelihood value that derives the estimated phase velocity.

  3. Ergophthalmology in accounting offices: the computer vision syndrome (CVS

    Directory of Open Access Journals (Sweden)

    Arjuna Nudi Perin

    Full Text Available Abstract Purpose: This study aimed to determine the presence of the symptoms of computer vision syndrome (CVS accounting office employees. Methods: The research tools used were a questionnaire based on the set of symptoms of CVS rated by Likert scale (1-5 and workplace observations based on Ergonomic Workplace Analysis (EWA. Results: The participants who worked with a viewing angle of less than 10º relative to the screen had more symptoms, particularly of pain in the back of the neck and back (p = 0.0460. The participants who used lighting other than 450 and 699 lux reported significant headache (p = 0.0045 and dry eye (p = 0.0329 symptoms. Younger workers had more headaches (p = 0.0182, and workers with fewer years of employment had more headaches and dry eyes symptoms (p = 0.0164 and p = 0.0479, respectively. A total of 37% of the participants reported a lack of guidance regarding prevention and painful symptoms in the back of the neck and back (p = 0.0936. Conclusion: Younger participants with fewer years of employment, who had not received information regarding proper computer use, who did not use lighting between 450 and 699 lux or who worked with viewing angles of less than 10º had more computer vision syndrome symptoms.

  4. Chorionic villus sampling

    Science.gov (United States)

    ... medlineplus.gov/ency/article/003406.htm Chorionic villus sampling To use the sharing features on this page, please enable JavaScript. Chorionic villus sampling (CVS) is a test some pregnant women have ...

  5. Samen leven met ME/CVS : Een onderzoek naar de rol van partnersteun en ziekterepresentaties bij coping met en adaptatie aan ME/CVS.

    NARCIS (Netherlands)

    Marleen Hofman, [No Value

    2013-01-01

    Achtergrond: Het chronisch vermoeidheidssyndroom (CVS) is een chronische ziekte die wordt gekenmerkt door ernstige vermoeidheid die vaak gepaard gaat met reumatische, infectieuze en neuropsychiatrische klachten. Het is een ernstig invaliderende aandoening waar tot nog toe geen genezende behandeling

  6. 77 FR 2724 - CVS Caremark Corporation; Analysis of Proposed Consent Order To Aid Public Comment

    Science.gov (United States)

    2012-01-19

    ... ``donut hole,'' at which point the beneficiary pays the full cost of the drugs. The Commission's complaint... estimates of the prices that beneficiaries would pay for those drugs at CVS and Walgreens. Rather, the... discrepancy, many RxAmerica beneficiaries using CVS Pharmacy and Walgreens stores ran through their benefits...

  7. Web TA Production (WebTA)

    Data.gov (United States)

    US Agency for International Development — WebTA is a web-based time and attendance system that supports USAID payroll administration functions, and is designed to capture hours worked, leave used and...

  8. Synthesis of Ni3Ta, Ni2Ta and NiTa by high-energy ball milling and subsequent heat treatment

    International Nuclear Information System (INIS)

    Benites, H.S.N.; Silva, B.P da; Ramos, A.S.; Silva, A.A.A.P.; Coelho, G.C.; Lima, B.B. de

    2014-01-01

    The tantalum has relevance for the development of multicomponent Ni-based superalloys which are hardened by solid solution and precipitation mechanisms. Master alloys are normally used in the production step in order to produce refractory metals and alloys. The present work reports on the synthesis of Ni_3Ta, Ni_2Ta and NiTa by high-energy ball milling and subsequent heat treatment. The elemental Ni-25Ta, Ni-33Ta and Ni-50Ta (at.-%) powder mixtures were ball milled under Ar atmosphere using stainless steel balls and vials, 300 rpm and a ball-to-powder weight ratio of 10:1. Following, the as-milled samples were uniaxially compacted and heat-treated at 1100 deg C for 4h under Ar atmosphere. The characterization of as-milled and heat-treated samples was conducted by means of X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry. A large amount of Ni_3Ta, Ni_2Ta and NiTa was formed in the mechanically alloyed heat-treated Ni-25Ta, Ni-33Ta and Ni-50Ta alloys. (author)

  9. Sorption and desorption of cesium and strontium on TA-2 and TA-41 soils and sediments

    International Nuclear Information System (INIS)

    Kung, K. Stephen; Li, Benjamin W.; Longmire, P.A.; Fowler, M.M.

    1996-04-01

    Current environmental monitoring has detected radioactive contaminants in alluvial groundwater, soils, and sediments in the TA-2 and TA-41 areas along the north central edge of Los Alamos National Laboratory. Because of this contamination, this study was initiated. The objective of this study is to quantify the sorptivity of cesium and strontium onto TA-2 and TA-41 site specific soil samples under a controlled environment in the laboratory. The purposes of this work are to determine cesium and strontium sorption coefficient for these sit specific soils and to evaluate the potential transport of cesium and strontium. Based on this information, a risk assessment and remediation strategy can be developed

  10. Cyclic Vomiting Syndrome (CVS: is there a difference based on onset of symptoms - pediatric versus adult?

    Directory of Open Access Journals (Sweden)

    Kumar Nilay

    2012-05-01

    Full Text Available Abstract Background Cyclic Vomiting Syndrome (CVS is a well-recognized functional gastrointestinal disorder in children but its presentation is poorly understood in adults. Genetic differences in pediatric-onset (presentation before age 18 and adult-onset CVS have been reported recently but their clinical features and possible differences in response to therapy have not been well studied. Methods This was a retrospective review of 101 CVS patients seen at the Medical College of Wisconsin between 2006 and 2008. Rome III criteria were utilized to make the diagnosis of CVS. Results Our study population comprised of 29(29% pediatric-onset and 72 (71% adult-onset CVS patients. Pediatric-onset CVS patients were more likely to be female (86% vs. 57%, p = 0.005 and had a higher prevalence of CVS plus (CVS + neurocognitive disorders as compared to adult-onset CVS patients (14% vs. 3%, p = 0.05. There was a longer delay in diagnosis (10 ± 7 years in the pediatric-onset group when compared to (5 ± 7 years adult-onset CVS group (p = 0.001. Chronic opiate use was less frequent in the pediatric-onset group compared to adult-onset patients (0% vs. 23%, p = 0.004. Aside from these differences, the two groups were similar with regards to their clinical features and the time of onset of symptoms did not predict response to standard treatment. The majority of patients (86% responded to treatment with tricyclic antidepressants, anticonvulsants (topiramate, coenzyme Q-10, and L-carnitine. Non-response to therapy was associated with coalescence of symptoms, chronic opiate use and more severe disease as characterized by longer episodes, greater number of emergency department visits in the year prior to presentation, presence of disability and non-compliance on univariate analysis. On multivariate analysis, only compliance to therapy was associated with a response. (88% vs. 38%, Odds Ratio, OR 9.6; 95% Confidence Interval [CI], 1.18-77.05. Conclusion Despite reported

  11. Safety assessment for TA-48 radiochemical operations

    International Nuclear Information System (INIS)

    1994-08-01

    The purpose of this report is to document an assessment performed to evaluate the safety of the radiochemical operations conducted at the Los Alamos National Laboratory operations area designated as TA-48. This Safety Assessment for the TA-48 radiochemical operations was prepared to fulfill the requirements of US Department of Energy (DOE) Order 5481.1B, ''Safety Analysis and Review System.'' The area designated as TA-48 is operated by the Chemical Science and Technology (CST) Division and is involved with radiochemical operations associated with nuclear weapons testing, evaluation of samples collected from a variety of environmental sources, and nuclear medicine activities. This report documents a systematic evaluation of the hazards associated with the radiochemical operations that are conducted at TA-48. The accident analyses are limited to evaluation of the expected consequences associated with a few bounding accident scenarios that are selected as part of the hazard analysis. Section 2 of this report presents an executive summary and conclusions, Section 3 presents pertinent information concerning the TA-48 site and surrounding area, Section 4 presents a description of the TA-48 radiochemical operations, and Section 5 presents a description of the individual facilities. Section 6 of the report presents an evaluation of the hazards that are associated with the TA-48 operations and Section 7 presents a detailed analysis of selected accident scenarios

  12. Radiological soil survey adjacent to TA-35, TA-48, TA-50, and TA-55

    International Nuclear Information System (INIS)

    Purtymun, W.D.; Becker, N.M.; Maes, M.N.

    1985-01-01

    The 137 Cs concentrations in soil from five new locations (in technical areas where radioactive materials are processed or have been processed) are at or below the maximum levels (1.4 pCi/g) found in regional soils. The 238 Pu and /sup 239,240/Pu soil concentrations at Station 2 were greater than were those found in regional soils (1977 and 1978-1982 Summaries). Station 2 is located south of TA-50. The total uranium soil concentrations exceed regional background concentrations at all stations. However, these levels do not indicate contamination but reflect natural uranium leached from soil derived from the tuff. These concentrations are similar to the data collected in 1977. Uranium concentrations in soils vary and depend on the rock type that has weathered to form the soil. A comparison of the averages and standard deviations of radiochemical analyses collected in 1977 and 1983 indicates only slight variations between the 2 yr. The five new stations established in 1983 will provide long-term monitoring of the possible airborne deposition of contaminants in the areas around TA-35, TA-48, TA-50, and TA-55. Comparing 1977 with 1983 data indicates no significant increase in radioactivity of the soil adjacent to these technical areas

  13. Spectroscopy of 169Ta

    International Nuclear Information System (INIS)

    Kshetri, Ritesh; Ray, I.; Ganguly, S.; Pradhan, M.K.; Raut, R.; Goswami, A.; Banerjee, P.; Mukherjee, A.; Datta Pramanik, U.; Bhattacharya, S.; Dasmahapatra, B.; Saha Sarkar, M.; Dey, G.; Ray Basu, M.; Krishichayan; Chakraborty, A.; Ghugre, S.S.; Ray, M.; Sarkar, S.

    2006-01-01

    The lifetimes of the isomeric levels of 169,171 Ta have been re-measured using the centroid shift method of electronic timing technique. Preliminary results for lifetimes are in good agreement with the adopted values. Investigations are being carried out to identify other isomeric levels

  14. Migration of the Gaudi and LHCb software repositories from CVS to Subversion

    International Nuclear Information System (INIS)

    Clemencic, M; Degaudenzi, H

    2011-01-01

    A common code repository is of primary importance in a distributed development environment such as large HEP experiments. CVS (Concurrent Versions System) has been used in the past years at CERN for the hosting of shared software repositories, among which were the repositories for the Gaudi Framework and the LHCb software projects. Many developers around the world produced alternative systems to share code and revisions among several developers, mainly to overcome the limitations in CVS, and CERN has recently started a new service for code hosting based on the version control system Subversion. The differences between CVS and Subversion and the way the code was organized in Gaudi and LHCb CVS repositories required careful study and planning of the migration. Special care was used to define the organization of the new Subversion repository. To avoid as much as possible disruption in the development cycle, the migration has been gradual with the help of tools developed explicitly to hide the differences between the two systems. The principles guiding the migration steps, the organization of the Subversion repository and the tools developed will be presented, as well as the problems encountered both from the librarian and the user points of view.

  15. Migration of the Gaudi and LHCb software repositories from CVS to Subversion

    Science.gov (United States)

    Clemencic, M.; Degaudenzi, H.; LHCb Collaboration

    2011-12-01

    A common code repository is of primary importance in a distributed development environment such as large HEP experiments. CVS (Concurrent Versions System) has been used in the past years at CERN for the hosting of shared software repositories, among which were the repositories for the Gaudi Framework and the LHCb software projects. Many developers around the world produced alternative systems to share code and revisions among several developers, mainly to overcome the limitations in CVS, and CERN has recently started a new service for code hosting based on the version control system Subversion. The differences between CVS and Subversion and the way the code was organized in Gaudi and LHCb CVS repositories required careful study and planning of the migration. Special care was used to define the organization of the new Subversion repository. To avoid as much as possible disruption in the development cycle, the migration has been gradual with the help of tools developed explicitly to hide the differences between the two systems. The principles guiding the migration steps, the organization of the Subversion repository and the tools developed will be presented, as well as the problems encountered both from the librarian and the user points of view.

  16. 76 FR 49453 - CVS Pharmacy, Inc., Provisional Acceptance of a Settlement Agreement and Order

    Science.gov (United States)

    2011-08-10

    ...; telephone (301) 504-7612. SUPPLEMENTARY INFORMATION: The text of the Agreement and Order appears below... hooded fleece jackets with drawstrings at the neck (``Jackets''). 5. CVS sold the Jackets, and/or held... (``Guidelines'') to help prevent children from strangling or entangling on neck and waist drawstrings. The...

  17. Electric-field gradients at Ta donor impurities in Cr2O3(Ta) semiconductor

    International Nuclear Information System (INIS)

    Darriba, G.N.; Errico, L.A.; Munoz, E.L; Richard, D.; Eversheim, P.D.; Renteria, M.

    2009-01-01

    We report perturbed-angular-correlation (PAC) experiments on 181 Hf(→ 181 Ta)-implanted corundum Cr 2 O 3 powder samples in order to determine the magnitude and symmetry of the electric-field gradient (EFG) tensor at Ta donor impurity sites of this semiconductor. These results are analyzed in the framework of ab initio full-potential augmented-plane wave plus local orbitals (FP-APW+lo) calculations. The results are also compared with EFG results coming from PAC experiments in isomorphous α-Al 2 O 3 and α-Fe 2 O 3 doped with 111 In→ 111 Cd and 181 Hf→ 181 Ta tracers. This combined analysis enables us to quantify the magnitude of the lattice relaxations induced by the presence of the impurity and to determine the charge state of the impurity donor level introduced by Ta in the band gap of the semiconductor.

  18. 40 CFR 89.422 - Dilute sampling procedures-CVS calibration.

    Science.gov (United States)

    2010-07-01

    ... the standard deviation. (v) If the standard deviation exceeds 0.3 percent of the average K v, take... = Meter air flow rate in standard cubic meters per minute, standard conditions are 0 °C, 101.3 kPa. n=Pump...). Pressure drop across LFE matrix EDP kPa (Inches H2O) 0.001 (0.005). Air flow Qs m3/min. (Ft3/min) 0.5 pct...

  19. Cyclic Vomiting Syndrome (CVS): is there a difference based on onset of symptoms--pediatric versus adult?

    Science.gov (United States)

    Kumar, Nilay; Bashar, Qumseya; Reddy, Naveen; Sengupta, Jyotirmoy; Ananthakrishnan, Ashwin; Schroeder, Abigail; Hogan, Walter J; Venkatesan, Thangam

    2012-05-28

    Cyclic Vomiting Syndrome (CVS) is a well-recognized functional gastrointestinal disorder in children but its presentation is poorly understood in adults. Genetic differences in pediatric-onset (presentation before age 18) and adult-onset CVS have been reported recently but their clinical features and possible differences in response to therapy have not been well studied. This was a retrospective review of 101 CVS patients seen at the Medical College of Wisconsin between 2006 and 2008. Rome III criteria were utilized to make the diagnosis of CVS. Our study population comprised of 29(29%) pediatric-onset and 72 (71%) adult-onset CVS patients. Pediatric-onset CVS patients were more likely to be female (86% vs. 57%, p = 0.005) and had a higher prevalence of CVS plus (CVS + neurocognitive disorders) as compared to adult-onset CVS patients (14% vs. 3%, p = 0.05). There was a longer delay in diagnosis (10 ± 7 years) in the pediatric-onset group when compared to (5 ± 7 years) adult-onset CVS group (p = 0.001). Chronic opiate use was less frequent in the pediatric-onset group compared to adult-onset patients (0% vs. 23%, p = 0.004). Aside from these differences, the two groups were similar with regards to their clinical features and the time of onset of symptoms did not predict response to standard treatment. The majority of patients (86%) responded to treatment with tricyclic antidepressants, anticonvulsants (topiramate), coenzyme Q-10, and L-carnitine. Non-response to therapy was associated with coalescence of symptoms, chronic opiate use and more severe disease as characterized by longer episodes, greater number of emergency department visits in the year prior to presentation, presence of disability and non-compliance on univariate analysis. On multivariate analysis, only compliance to therapy was associated with a response. (88% vs. 38%, Odds Ratio, OR 9.6; 95% Confidence Interval [CI], 1.18-77.05). Despite reported genetic differences, the clinical features and

  20. Comparative study of Ta, TaN and Ta/TaN bi-layer barriers for Cu-ultra low-k porous polymer integration

    International Nuclear Information System (INIS)

    Yang, L.Y.; Zhang, D.H.; Li, C.Y.; Foo, P.D.

    2004-01-01

    Tantalum (Ta), TaN and bilayer Ta/TaN barriers deposited on ultra-low-k porous polymer (ULKPP) and the thermal stability of their structures are comparatively investigated using various techniques. The Ta/ultra-low-k polymer shows the smallest sheet resistance, but the poorest thermal stability, while TaN on the ultra-low-k polymer shows the highest resistance but the best thermal stability. The bi-layer Ta/TaN barrier takes the advantage of both Ta and TaN barriers and gives reasonable resistance and thermal stability. The electrical tests indicate that the Cu lines with the TaN and bi-layer Ta/TaN barriers exhibit the smaller leakage current and higher breakdown voltage compared with the Cu lines with the Ta barrier. The better thermal stability of the TaN and the bi-layer Ta/TaN barriers is mainly due to the amorphous/nanostructure and less grain boundaries of the barriers. In addition, the texture discontinuity at the Ta/TaN interfaces in the bi-layers barrier also plays an important role in reducing mutual diffusion of Ta atoms in the Ta barrier and some atoms in the ultra-low-k porous polymer

  1. Investigation of TaC–TaB2 ceramic composites

    Indian Academy of Sciences (India)

    ture and the mechanical properties of the composites were investigated. The results .... 300 nm. Jingangzuan in the TaC/TaB2 composites SPS for 10 min at different temperatures are .... [1] Liu L, Yea F, Hea X and Zhoua Y 2011 Mater. Chem.

  2. Interdisciplinary Integration of the CVS Module and Its Effect on Faculty and Student Satisfaction as Well as Student Performance

    Directory of Open Access Journals (Sweden)

    Ayuob Nasra N

    2012-07-01

    Full Text Available Abstract Background Beyond the adoption of the principles of horizontal and vertical integration, significant planning and implementation of curriculum reform is needed. This study aimed to assess the effect of the interdisciplinary integrated Cardiovascular System (CVS module on both student satisfaction and performance and comparing them to those of the temporally coordinated CVS module that was implemented in the previous year at the faculty of Medicine of the King Abdulaziz University, Saudi Arabia. Methods This interventional study used mixed method research design to assess student and faculty satisfaction with the level of integration within the CVS module. A team from the medical education department was assembled in 2010/2011 to design a plan to improve the CVS module integration level. After delivering the developed module, both student and faculty satisfaction as well as students performance were assessed and compared to those of the previous year to provide an idea about module effectiveness. Results Many challenges faced the medical education team during design and implementation of the developed CVS module e.g. resistance of faculty members to change, increasing the percentage of students directed learning hours from the total contact hour allotted to the module and shifting to integrated item writing in students assessment, spite of that the module achieved a significant increase in both teaching faculty and student satisfaction as well as in the module scores. Conclusion The fully integrated CVS has yielded encouraging results that individual teachers or other medical schools who attempt to reformulate their curriculum may find valuable.

  3. 179Ta and 180Ta structure by transfer reactions

    International Nuclear Information System (INIS)

    Warde, Elias.

    1979-01-01

    Transfer reactions (α,t); ( 3 He,d); (p,t) and (p,d) have been used to study the nuclear spectroscopy of 179 Ta and 180 Ta. In 179 Ta, 5/2 - and 9/2 - states of the 1/2(541) configuration have been identified. The core-quasiproton interaction has to be taken into account in order to explain the two-nucleon transfer intensities in the 181 Ta(p,t) 179 Ta reaction. A level scheme has been proposed for 180 Ta for the first time. Especially the ground state is identified with the (1 + ,1) level of the [7/2 + (404)sub(p), 9/2 + (624)sub(n)] configuration and spin (9 - ,9) of the configuration [9/2 - (514)sub(p), 9/2 + (624)sub(n)] has been assigned to the long-lived isomer. From the observed configurations in 180 Ta, the matrix elements of the effective residual interaction vsub(np) have been deduced and compared to theoretical predictions [fr

  4. An Internet survey of marijuana and hot shower use in adults with cyclic vomiting syndrome (CVS).

    Science.gov (United States)

    Venkatesan, Thangam; Sengupta, Jyotirmoy; Lodhi, Atena; Schroeder, Abigail; Adams, Kathleen; Hogan, Walter J; Wang, Yanzhi; Andrews, Christopher; Storr, Martin

    2014-08-01

    Cyclic vomiting syndrome (CVS) is a chronic disorder characterized by episodic nausea and vomiting. A large proportion of patients use marijuana to control their symptoms. Several case reports implicate marijuana as a cause of intractable vomiting with compulsive hot water bathing considered pathognomonic of "cannabinoid hyperemesis." We sought to examine the relationship between marijuana use and CVS. Patients >18 years of age diagnosed by a health care provider were invited to participate in an anonymous internet-based survey. A total of 514 patients participated and 437 completed questions about marijuana use. Mean age was 34 ± 12 years with patients being predominantly female (63%), Caucasian (92%) and from the USA (82%). Nineteen percent never used marijuana and 81% did. Fifty-four percent used marijuana for health issues and 43% for recreational purposes. Users stated that it improved nausea, appetite, general well-being, stress levels and vomiting. Users were more likely to be male and have an associated anxiety disorder. Sixty-seven percent of patients reported taking hot showers/baths for symptom relief, and this was associated with marijuana use. (OR 2.54, CI 1.50-4.31, P = 0.0006). Eighty-one percent of patients with CVS who completed an internet survey reported frequent use of marijuana. With marijuana use, patients noted the greatest improvement with stress levels, appetite and nausea. Marijuana users were more likely to be male and have associated anxiety. Hot showers were not pathognomonic of marijuana use though they were more likely to be associated with its use.

  5. Field investigations of soils at TA-19, TA-26, TA-73 and TA-0, SWMU aggregate 0-D and 016

    International Nuclear Information System (INIS)

    McFadden, L.D.

    1995-01-01

    Field based investigations of the general soil-geomorphic characteristics were carried out at TA-19, -26, -73, -0, Aggregate 0-D and -016 in order to provide information for utilization in ongoing and anticipated LANL ERP (Environmental Restoration Project) activities at these sites. These investigations show that soils exhibiting diverse morphologic character, varying ages, and relations to landforms characterize these sites. A review of recent and ongoing soils studies also shows that soil textural, chemical, and mineralogical characteristics may profoundly influence the migration and/or retardation of a variety of potential contaminants initially placed in direct contact with soils, or that encounter soils during subsurface percolation or discharge. Soil-geomorphic relations also provide important insights into recent site erosion, deposition or other surficial processes that must, be considered as part of environmental assessment of a given site and remediation; and, the planned geomorphic mapping activities at each site, as well as other associated activities (e.g, geophysical survey, site sampling) are accordingly appropriate and necessary with respect to identification of significant soil relations at each site. Specific and general recommendations in consideration of important findings regarding the possible impacts of soil development of the nature of contaminant behavior at various sites are provided to help guide sampling and analysis activities during ERP investigations outlined in the RFI Work Plan for Operational Unit-1071

  6. New ternary tantalum borides containing boron dumbbells: Experimental and theoretical studies of Ta2OsB2 and TaRuB

    International Nuclear Information System (INIS)

    Mbarki, Mohammed; Touzani, Rachid St.; Rehorn, Christian W.G.; Gladisch, Fabian C.; Fokwa, Boniface P.T.

    2016-01-01

    The new ternary transition metal-rich borides Ta 2 OsB 2 and TaRuB have been successfully synthesized by arc-melting the elements in a water-cooled crucible under an argon atmosphere. The crystal structures of both compounds were solved by single-crystal X-ray diffraction and their metal compositions were confirmed by EDX analysis. It was found that Ta 2 OsB 2 and TaRuB crystallize in the tetragonal Nb 2 OsB 2 (space group P4/mnc, no. 128) and the orthorhombic NbRuB (space group Pmma, no. 51) structure types with lattice parameters a=5.878(2) Å, c=6.857(2) Å and a=10.806(2) Å, b=3.196(1) Å, c=6.312(2) Å, respectively. Furthermore, crystallographic, electronic and bonding characteristics have been studied by density functional theory (DFT). Electronic structure relaxation has confirmed the crystallographic parameters while COHP bonding analysis indicates that B 2 -dummbells are the strongest bonds in both compounds. Moreover, the formation of osmium dumbbells in Ta 2 OsB 2 through a Peierls distortion along the c-axis, is found to be the origin of superstructure formation. Magnetic susceptibility measurements reveal that the two phases are Pauli paramagnets, thus confirming the theoretical DOS prediction of metallic character. Also hints of superconductivity are found in the two phases, however lack of single phase samples has prevented confirmation. Furthermore, the thermodynamic stability of the two modifications of AMB (A=Nb, Ta; M =Ru, Os) are studied using DFT, as new possible phases containing either B 4 - or B 2 -units are predicted, the former being the most thermodynamically stable modification. - Graphical abstract: The two new ternary tantalum borides, Ta 2 OsB 2 and TaRuB, have been discovered. Their crystal structures contain boron dumbbells, which are the strongest bonds. Peirls distortion is found responsible for Os 2 -dumbbells formation in Ta 2 OsB 2 . Ta 2 OsB 2 and TaRuB are Pauli paramagnet and potential superconductors. - Highlights:

  7. Development of Ta3N5 as an Efficient Visible Light-responsive Photocatalyst for Water Oxidation

    KAUST Repository

    Nurlaela, Ela

    2015-01-01

    phase sample. The photophysical properties of Ta3N5, such as the absorption coefficient, carrier mobility, and carrier lifetime, have been experimentally measured by synthesizing Ta3N5 thin films. Very low kinetic properties with very low transport

  8. Coherent Vortex Simulation (CVS) of vortex-dipoles impinging on a no-slip wall

    Science.gov (United States)

    Schneider, Kai; Farge, Marie

    2004-11-01

    Recently, we have introduced a new wavelet-based method, called Coherent Vortex Simulation (CVS), to compute turbulent flows (Flow, Turbulence and Combustion 66(4), 2001). The main idea is to split the flow into two orthogonal parts, a coherent flow and an incoherent background flow, using a nonlinear wavelet filtering of vorticity (Phys. Fluids, 11(8), 1999). As the coherent flow is responsible for the nonlinear dynamics, its evolution is deterministically computed in an adaptive wavelet basis, while the incoherent background flow being noise-like, structureless and decorrelated, its influence on the coherent flow is statistically modelled. Since the coherent part is described by only few wavelets, it is possible to reduce the computational cost, both in terms of memory requirement and cpu time. In order to take into account no-slip boundary conditions, we coupled the adaptive wavelet solver with a volume penalization technique (ACHA, 12, 2002). Here, we present applications of the CVS method to compute vortex dipoles impinging on a no-slip wall in a square container at different Reynolds numbers, which is a challenging test case for numerical methods. We observe the creation of strong vorticity gradients and the production of enstrophy when the dipole hits the wall. We show that the computational grid is dynamically adapted to the dipole evolution, since the wavelet nonlinear filter automatically refines the grid in regions of strong gradients. Note that during the computation only 5% out of 1024^2 wavelet coefficients are thus used.

  9. Fetal cell detection in maternal blood : A study in 236 samples using erythroblast morphology, DAB and HbF staining, and FISH analysis

    NARCIS (Netherlands)

    Oosterwijk, JC; Mesker, WE; Ouwerkerk-van Velzen, MCM; Knepfle, CFHM; Wiesmeijer, KC; Beverstock, GC; van Ommen, GJB; Kanhai, HHH; Tanke, HJ

    1998-01-01

    A protocol to detect fetal nucleated red blood cells (NRBCs) was tested in 217 pregnant women and in 19 nonpregnant controls. All the pregnant women were sampled after chorionic villus sampling (CVS); 20 were also sampled pre-CVS. NRBC recognition was based upon morphology by using staining of

  10. The role of abnormal fetal heart rate in scheduling chorionic villus sampling.

    Science.gov (United States)

    Yagel, S; Anteby, E; Ron, M; Hochner-Celnikier, D; Achiron, R

    1992-09-01

    To assess the value of fetal heart rate (FHR) measurements in predicting spontaneous fetal loss in pregnancies scheduled for chorionic villus sampling (CVS). A prospective descriptive study. Two hospital departments of obstetrics and gynaecology in Israel. 114 women between 9 and 11 weeks gestation scheduled for chorionic villus sampling (CVS). Fetal heart rate was measured by transvaginal Doppler ultrasound and compared with a monogram established from 75 fetuses. Whenever a normal FHR was recorded, CVS was performed immediately. 106 women had a normal FHR and underwent CVS; two of these pregnancies ended in miscarriage. In five pregnancies no fetal heart beats could be identified and fetal death was diagnosed. In three pregnancies an abnormal FHR was recorded and CVS was postponed; all three pregnancies ended in miscarriage within 2 weeks. Determination of FHR correlated with crown-rump length could be useful in predicting spontaneous miscarriage before performing any invasive procedure late in the first trimester.

  11. Supporting data for senary refractory high-entropy alloy CrxMoNbTaVW

    Directory of Open Access Journals (Sweden)

    B. Zhang

    2015-12-01

    Full Text Available This data article is related to the research paper entitled “senary refractory high-entropy alloy CrxMoNbTaVW [1]”. In this data article, the pseudo-binary Cr-MoNbTaVW phase diagram is presented to show the impact of Cr content to the senary Cr-MoNbTaVW alloy system; the sub-lattice site fractions are presented to show the disordered property of the Cr-MoNbTaVW BCC structures; the equilibrium and Scheil solidification results with the actual sample elemental compositions are presented to show the thermodynamic information of the melted/solidified CrxMoNbTaVW samples; and the raw EDS scan data of the arc-melted CrxMoNbTaVW samples are also provided.

  12. Tuning the effective parameters in (Ta/Cu/[Ni/Co]x/Ta) multilayers with perpendicular magnetic anisotropy

    Science.gov (United States)

    Ayareh, Zohreh; Moradi, Mehrdad; Mahmoodi, Saman

    2018-06-01

    In this paper, we report perpendicular magnetic anisotropy (PMA) in a (Ta/Cu/[Ni/Co]x/Ta) multilayers structure. These typical structures usually include a multilayer of ferromagnetic and transition metal thin films. Usually, magnetic anisotropy is characterized by magnetization loops determined by magnetometer or magneto-optical Kerr effect (MOKE). The interface between ferromagnetic and metallic layers plays an important role in magnetic anisotropy evolution from out-of-plane to in-plane in (Ta/Cu/[Ni/Co]/Ta) structure. Obtained results from MOKE and magnetometry of these samples show that they have different easy axes due to change in thickness of Cu as spacer layer and difference in number of repetition of [Ni/Co] stacks.

  13. EUSO-TA prototype telescope

    Energy Technology Data Exchange (ETDEWEB)

    Bisconti, Francesca, E-mail: francesca.bisconti@kit.edu

    2016-07-11

    EUSO-TA is one of the prototypes developed for the JEM-EUSO project, a space-based large field-of-view telescope to observe the fluorescence light emitted by cosmic ray air showers in the atmosphere. EUSO-TA is a ground-based prototype located at the Telescope Array (TA) site in Utah, USA, where an Electron Light Source and a Central Laser Facility are installed. The purpose of the EUSO-TA project is to calibrate the prototype with the TA fluorescence detector in presence of well-known light sources and cosmic ray air showers. In 2015, the detector started the first measurements and tests using the mentioned light sources have been performed successfully. A first cosmic ray candidate has been observed, as well as stars of different magnitude and color index. Since Silicon Photo-Multipliers (SiPMs) are very promising for fluorescence telescopes of next generation, they are under consideration for the realization of a new prototype of EUSO Photo Detector Module (PDM). The response of this sensor type is under investigation through simulations and laboratory experimentation.

  14. EUSO-TA prototype telescope

    Science.gov (United States)

    Bisconti, Francesca; JEM-EUSO Collaboration

    2016-07-01

    EUSO-TA is one of the prototypes developed for the JEM-EUSO project, a space-based large field-of-view telescope to observe the fluorescence light emitted by cosmic ray air showers in the atmosphere. EUSO-TA is a ground-based prototype located at the Telescope Array (TA) site in Utah, USA, where an Electron Light Source and a Central Laser Facility are installed. The purpose of the EUSO-TA project is to calibrate the prototype with the TA fluorescence detector in presence of well-known light sources and cosmic ray air showers. In 2015, the detector started the first measurements and tests using the mentioned light sources have been performed successfully. A first cosmic ray candidate has been observed, as well as stars of different magnitude and color index. Since Silicon Photo-Multipliers (SiPMs) are very promising for fluorescence telescopes of next generation, they are under consideration for the realization of a new prototype of EUSO Photo Detector Module (PDM). The response of this sensor type is under investigation through simulations and laboratory experimentation.

  15. Comparison of Complications of Chorionic Villus Sampling and Amniocentesis

    Directory of Open Access Journals (Sweden)

    Nahid Shahbazian

    2012-01-01

    Full Text Available Background: A significant number of pregnancies are associated with the cytogenetic abnormalities of the fetus. Amniocentesis and chorionic villus sampling (CVS are procedures used for prenatal genetic diagnosis. In this study, we compare the safety and complications of mid-trimester amniocentesis and transabdominal CVS.Materials and Methods: This analytic cross-sectional study was performed in 308 patients from2.11.2007 to 26.10.2009. We had 155 cases of amniocentesis, which we performed in weeks 15-23 of pregnancy; and 153 cases of CVS, which we performed during weeks 10-14 of pregnancy.Results: There were 2 cases (1.2% of premature rupture of membrane (PROM in amniocentesis which occurred 1 and 10 days after the procedure and caused pregnancy loss before 20 weeks. We had 1 case (0.7% of abortion in CVS, which occurred 10 days after the procedure. Additionally, there was 1 case of amniotic fluid leakage (0.7% in which, after admission to the hospital and observation, leakage was stopped and the pregnancy continued normally.Conclusion: In this study, we had more complications with amniocentesis cases than CVS. CVS is a procedure performed in the earlier stages of pregnancy and its complications are less than amniocentesis. We suggest CVS to be the procedure of choice for genetic diagnosis.

  16. The TA and TALE Experiments

    International Nuclear Information System (INIS)

    Thomson, Gordon

    2006-01-01

    The TA/TALE experiment is under construction, and is being deployed in Millard County, Utah. It will consist of a suite of detectors covering four orders of magnitude in energy, from 10 16.5 to 10 20.5 eV, and will observe cosmic ray showers with fluorescence detectors and arrays of scintillation counters. Events will be seen by multiple detectors and cross calibration of detectors' energy scales will be possible. TA/TALE will observe all three features of the spectrum of ultrahigh energy cosmic rays, observe the galactic/extragalactic transition, study the cosmology of cosmic ray sources, and perform anisotropy studies with unprecedented accuracy

  17. Gold nanoparticles embedded in Ta 2 O 5 /Ta 3 N 5 as active visible-light plasmonic photocatalysts for solar hydrogen evolution

    KAUST Repository

    Luo, Yujing

    2014-07-10

    Here, we demonstrate a new recreating photocatalytic activity of a Nano Au/Ta2O5 composite for hydrogen evolution from water as a visible-light-responsive plasmonic photocatalyst by embedding Au nanoparticles in a Ta2O5 host lattice. The Nano Au/Ta2O 5 composite samples were prepared through a simple Pechini-type sol-gel process. Further nitridating Nano Au/Ta2O5 composite samples in ammonia flow at 1123 K yielded Nano Au/Ta3N 5 composite samples. The obtained Nano Au/Ta3N5 composite exhibited a significantly enhanced photocatalytic activity in the visible region for hydrogen evolution from water compared with blank Ta 3N5 nanoparticles. UV-visible diffuse reflectance spectra and photocatalytic activity measurements indicated that the excitation of surface plasmon resonance of Au nanoparticles is responsible for the new recreating photocatalytic activity of the Nano Au/Ta2O5 composite and significantly enhanced photocatalytic activity of the Nano Au/Ta3N5 composite for hydrogen evolution in the visible region, which might be ascribed to the charge transfer effect in Nano Au/Ta 2O5 composite and the synergetic effect of charge transfer and near-field electromagnetic effect in Nano Au/Ta3N5 composite induced by surface plasmon resonance of embedded Au nanoparticles. The current study could provide a new paradigm for designing plasmonic metal/semiconductor composite systems for photocatalytic, photovoltaic and other optoelectronic devices. © the Partner Organisations 2014.

  18. TA-55 change control manual

    International Nuclear Information System (INIS)

    Blum, T.W.; Selvage, R.D.; Courtney, K.H.

    1997-11-01

    This manual is the guide for initiating change at the Plutonium Facility, which handles the processing of plutonium as well as research on plutonium metallurgy. It describes the change and work control processes employed at TA-55 to ensure that all proposed changes are properly identified, reviewed, approved, implemented, tested, and documented so that operations are maintained within the approved safety envelope. All Laboratory groups, their contractors, and subcontractors doing work at TA-55 follow requirements set forth herein. This manual applies to all new and modified processes and experiments inside the TA-55 Plutonium Facility; general plant project (GPP) and line item funded construction projects at TA-55; temporary and permanent changes that directly or indirectly affect structures, systems, or components (SSCs) as described in the safety analysis, including Facility Control System (FCS) software; and major modifications to procedures. This manual does not apply to maintenance performed on process equipment or facility SSCs or the replacement of SSCs or equipment with documented approved equivalents

  19. Niobium Nb and tantalum Ta

    International Nuclear Information System (INIS)

    Busev, A.I.; Tiptsova, V.G.; Ivanov, V.M.

    1978-01-01

    The basic methods for determining niobium and tantalum in various objects are described. Nb and Ta are separated with the aid of N-benzoyl-N-phenylhydroxylamine by precipitating Nb(5) from a tartaric acid solution with subsequent precipitation of Ta from the filtrate. The gravimetric determination of Nb and Ta in steels is based on their quantitative separation from a diluted solution by way of hydrolysis with subsequent after-precipitation with phenylarsonic acid (in the absence of W). The gravimetric determination of Nb in the presence of W is carried out with the aid of Cupferron. To determine Nb in its carbide, Nb(5) reduced to Nb(3) is titrated with a solution of K 2 Cr 2 O 7 in the presence of phenyl-anthranilic acid. The photometric determination of Nb in tungsten-containing steels and in ores containing Ti, W, Mo and Cr is based on the rhodanide method. Nb is determined in alloys with Zr and Ti photometrically with the aid of 4-(2-pyridylazo)-resorcin and in alloyed steels with the aid of benzhydroxamic acid. The latter complex is extracted with chloroform. This method is used to determine Nb in rocks. The photometric determination of Ta in TiCl 4 is carried out with the aid of pyrogallol, in commercial niobium with the aid of methyl violet, and in steel with the aid of 4-(-pyridylazo)-resorcin. Also described is the polarographic determination of Nb in tantalum pentoxide

  20. Institutional Interpretation of Participatory TA

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Øjvind

    2014-01-01

    . The aim of the article is thus to relate the challenges of establishing and continuing pTA as a societal practice to the question of societal institutions and their logics. Towards this aim, the paper draws on a number of different theoretical directions within New Institutionalism and attempts to build...

  1. Core level photoemission spectroscopy and chemical bonding in Sr2Ta2O7

    DEFF Research Database (Denmark)

    Atuchin, V. V.; Grivel, Jean-Claude; Zhang, Z. M.

    2009-01-01

    Electronic parameters of constituent element core levels of strontium pyrotantalate (Sr2Ta2O7) were measured with X-ray photoelectron spectroscopy (XPS). The Sr2Ta2O7 powder sample was synthesized using standard solid state method. The valence electron transfer on the formation of the Sr-O and Ta......-O bonds was characterized by the binding energy differences between the O 1s and cation core levels, Delta(O-Sr) = BE(O 1s) - BE(Sr 3d(5/2)) and Delta(O-Ta) = BE(O 1s) - BE(Ta 4f(7/2)). The chemical bonding effects were considered on the basis of our XPS results for Sr2Ta2O7 and earlier published...

  2. Sirc-cvs cytotoxicity test: an alternative for predicting rodent acute systemic toxicity.

    Science.gov (United States)

    Kitagaki, Masato; Wakuri, Shinobu; Hirota, Morihiko; Tanaka, Noriho; Itagaki, Hiroshi

    2006-10-01

    An in vitro crystal violet staining method using the rabbit cornea-derived cell line (SIRC-CVS) has been developed as an alternative to predict acute systemic toxicity in rodents. Seventy-nine chemicals, the in vitro cytotoxicity of which was already reported by the Multicenter Evaluation of In vitro Toxicity (MEIC) and ICCVAM/ECVAM, were selected as test compounds. The cells were incubated with the chemicals for 72 hrs and the IC(50) and IC(35) values (microg/mL) were obtained. The results were compared to the in vivo (rat or mouse) "most toxic" oral, intraperitoneal, subcutaneous and intravenous LD(50) values (mg/kg) taken from the RTECS database for each of the chemicals by using Pearson's correlation statistics. The following parameters were calculated: accuracy, sensitivity, specificity, prevalence, positive predictability, and negative predictability. Good linear correlations (Pearson's coefficient; r>0.6) were observed between either the IC(50) or the IC(35) values and all the LD(50) values. Among them, a statistically significant high correlation (r=0.8102, p50) values and the oral LD(50) values. By using the cut-off concentrations of 2,000 mg/kg (LD(50)) and 4,225 microg/mL (IC(50)), no false negatives were observed, and the accuracy was 84.8%. From this, it is concluded that this method could be used to predict the acute systemic toxicity potential of chemicals in rodents.

  3. Rotational structures in 174Ta

    International Nuclear Information System (INIS)

    Hojman, Daniel; Kreiner, A.J.; Davidson, Miguel

    1989-01-01

    The nucleus 174 Ta has been studied for the first time through the fusion-evaporation reaction 169 Tm ( 9 Be,4n) using a 4 mg/cm 2 self-supporting Tm foil in the 40 to 65 MeV bombarding energy range (the 4n channel was found to peak at 50 MeV). The experiments comprised γ and X-ray singles in beam and activity spectra, γ-γ-t coincidences (one of the counters was Compton suppressed) and γ-ray angular distributions. The results obtained allowed the construction of a high-spin level scheme. This scheme, which resembles that of 172 Ta, comprises several rotational bands which correspond to different couplings of the valence nucleons. One of these structures, the doubly decoupled band (DDB), is particularly interesting because it is the first observed case of a DDB based on an I π =3 + state. (Author) [es

  4. Effects of helium and deuterium irradiation on SPS sintered W–Ta composites at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Mateus, R., E-mail: rmateus@ipfn.ist.utl.pt [Associação Euratom/IST, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Dias, M. [ITN, Instituto Tecnológico e Nuclear, Estrada Nacional 10, 2686-953 Sacavém (Portugal); Lopes, J. [ITN, Instituto Tecnológico e Nuclear, Estrada Nacional 10, 2686-953 Sacavém (Portugal); ISEL, Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emídio Navarro, 1, 1959-007 Lisboa (Portugal); Rocha, J.; Catarino, N.; Franco, N. [ITN, Instituto Tecnológico e Nuclear, Estrada Nacional 10, 2686-953 Sacavém (Portugal); Livramento, V. [Associação Euratom/IST, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); LNEG, Laboratório Nacional de Energia e Geologia, Estrada do Paço do Lumiar, 1649-038 Lisboa (Portugal); and others

    2013-11-15

    Energetic He{sup +} and D{sup +} ions were implanted into different W–Ta composites in order to investigate their stability under helium and deuterium irradiation. The results were compared with morphological and chemical modifications arising from exposure of pure W and Ta. Special attention was given to tantalum hydride (Ta{sub 2}H) formation due to its implications for tritium inventory. Three W–Ta composites with 10 and 20 at.% Ta were prepared from elemental W powder and Ta fibre or powder through low-energy ball milling in argon atmosphere. Spark plasma sintering (SPS) was used as the consolidation process in the temperature range from 1473 to 1873 K. The results obtained from pure elemental samples and composites are similar. However, Ta{sub 2}H is easily formed in pure Ta by using a pre-implantation stage of He{sup +}, whereas in W–Ta composites the same reaction is clearly reduced, and it can be inhibited by controlling the sintering temperature.

  5. A tunnelling study on polymer/1T-LixTaS2 layered nanocomposites

    International Nuclear Information System (INIS)

    Enomoto, Hiroyuki; Takai, Hiroyuki; Ozaki, Hajime; Lerner, Michael M

    2004-01-01

    Electronic structures near the Fermi level of polymer/1T-Li x TaS 2 layered nanocomposites have been studied by tunnelling spectroscopy. Polymer/1T-Li x TaS 2 layered nanocomposites were synthesized by using the exfoliation-adsorption technique. Single crystals of 1T-TaS 2 were used as host materials. Poly(ethylene oxide) (PEO) and poly(ethylenimine) (PEI) with different molecular weights were adopted as guest intercalants. Powder x-ray diffraction patterns showed that all samples of the polymer/1T-Li x TaS 2 layered nanocomposites contain organic polymer between all individual 1T-TaS 2 sheets. Although 1T-TaS 2 single crystal is well known to show quite unique temperature dependences of the resistivity due to the charge density wave (CDW), the resistivities of all polymer/1T-Li x TaS 2 nanocomposites showed semiconductor-like temperature dependences. The tunnelling spectra of polymer/1T-Li x TaS 2 nanocomposites revealed that the CDW gap disappears in the density of states near the Fermi level of polymer/1T-Li x TaS 2 nanocomposites and their electronic structures show a metallic behaviour

  6. Superconductivity in palladium-doped 2H-TaS2

    Science.gov (United States)

    Zhou, M. H.; Li, X. C.; Dong, C.

    2018-06-01

    A series of Pd x TaS2 (0.01 ≤ x ≤ 0.08) samples were prepared and characterized via scanning electron microscope, x-ray powder diffraction, resistivity, magnetization and specific heat measurements. The lattice parameter c associated with the interlayer distance increases monotonically with the Pd content while the parameter a remains essentially constant. The crystal structure of Pd0.08TaS2 has been determined and refined by Rietveld refinement. Pd0.08TaS2 is hexagonal (space group: P31c) with lattice parameters a = 3.3151(1) Å, c = 12.1497(9) Å. The superconducting transition temperature T c (0.8 K) of TaS2 can be dramatically enhanced by Pd doping, and the maximum T c of 4.2 K, about five times the T c of pure TaS2, is obtained in Pd0.04TaS2. We have determined the superconducting parameters of Pd0.04TaS2, and found that the enhancement of T c can be attributed to the increase of density of states at the Fermi level. The charge density wave (CDW) of TaS2 is gradually suppressed with Pd doping and disappears in Pd0.06TaS2. This suggests that there is a competitive interplay between superconductivity and CDW in this system.

  7. Comparative Raman study of Weyl semimetals TaAs, NbAs, TaP and NbP

    International Nuclear Information System (INIS)

    Liu, H W; Richard, P; Zhao, L X; Chen, G-F; Ding, H

    2016-01-01

    We report a comparative polarized Raman study of Weyl semimetals TaAs, NbAs, TaP and NbP. The evolution of the phonon frequencies with the sample composition allows us to determine experimentally which atoms are mainly involved for each vibration mode. Our results confirm previous first-principles calculations indicating that the A 1 , B 1 (2), E(2) and E(3) modes involve mainly the As(P) atoms, the B 1 (1) mode is mainly related to Ta(Nb) atoms, and the E(1) mode involves both kinds of atoms. By comparing the energy of the different modes, we establish that the B 1 (1), B 1 (2), E(2) and E(3) become harder with increasing chemical pressure. This behaviour differs from our observation on the A 1 mode, which decreases in energy, in contrast to its behaviour under external pressure. (paper)

  8. Method of quantitative x-ray diffractometric analysis of Ta-Ta2C system

    International Nuclear Information System (INIS)

    Gavrish, A.A.; Glazunov, M.P.; Korolev, Yu.M.; Spitsyn, V.I.; Fedoseev, G.K.

    1976-01-01

    The syste86 Ta-Ta 2 C has beemonsidered because of specific features of diffraction patterns of the components, namely, overlapping of the most intensive reflexes of both phases. The method of standard binary system has been used for quantitative analysis. Because of overlapping of the intensive reflexes dsub(1/01)=2.36(Ta 2 C) and dsub(110)=2.33(Ta), the other, most intensive, reflexes have been used for quantitative determination of Ta 2 C and Ta: dsub(103)=1.404 A for tantalum subcarbide and dsub(211)=1.35A for tantalum. Besides, the TaTa 2 C phases have been determined quantitatively with the use of another pair of reflexes: dsub(102)=1.82 A for Ta 2 C and dsub(200)=1.65 A for tantalum. The agreement between the results obtained while performing the quantitative phase analysis is good. To increase reliability and accuracy of the quantitative determination of Ta and Ta 2 C, it is expedient to carry out the analysis with the use of two above-mentioned pairs of reflexes located in different regions of the diffraction spectrum. Thus, the procedure of quantitative analysis of Ta and Ta 2 C in different ratios has been developed taking into account the specific features of the diffraction patterns of these components as well as the ability of Ta 2 C to texture in the process of preparation

  9. Sampling

    CERN Document Server

    Thompson, Steven K

    2012-01-01

    Praise for the Second Edition "This book has never had a competitor. It is the only book that takes a broad approach to sampling . . . any good personal statistics library should include a copy of this book." —Technometrics "Well-written . . . an excellent book on an important subject. Highly recommended." —Choice "An ideal reference for scientific researchers and other professionals who use sampling." —Zentralblatt Math Features new developments in the field combined with all aspects of obtaining, interpreting, and using sample data Sampling provides an up-to-date treat

  10. Electrodeposited ultrafine TaOx/CB catalysts for PEFC cathode application: Their oxygen reduction reaction kinetics

    KAUST Repository

    Seo, Jeongsuk

    2014-12-01

    Ultrafine TaOx nanoparticles were electrodeposited on carbon black (CB) powder in a nonaqueous Ta complex solution at room temperature, and the resultant TaOx/CB catalysts were assessed as oxygen reduction reaction (ORR) electrocatalysts for polymer electrolyte fuel cell (PEFC) cathodes. The Ta electrodeposition process was scaled up using a newly designed working electrode containing a CB dense layer, without introducing any binder such as the ionomer Nafion in the electrode for electrodeposition. The electrodeposited TaOx/CB powders were removed from the deposition electrode and subsequent H2 treatment at varying temperatures between 523 and 1073 K was attempted to increase the ORR performance. The TaOx/CB samples were characterized by SEM, STEM, XPS, and EELS measurements. XPS and EELS results indicated the reduced nature of the Ta species caused by the high-temperature treatment in H2, while STEM images clearly revealed that the TaOx particles aggregated as the treatment temperature increased. When the TaOx/CB catalyst, which was treated at 873 K for 2 h, was deposited on a glassy carbon substrate with Nafion ionomer, it resulted in the highest activity among the samples investigated, giving an onset potential of 0.95 VRHE at -2 μA cm-2 in a 0.1 M H2SO4 solution. Moreover, the long-term stability test with 10,000 cycles of the voltammetry only led to a 6% loss in the ORR currents, demonstrating the high stability of the TaOx/CB catalysts. Kinetic analysis by R(R)DE indicated that the four-electron transfer pathway in the ORR process was dominant for this TaOx/CB catalyst, and Tafel plots showed a slope corresponding to a one-electron reaction for the rate-determining step.

  11. Electrodeposited ultrafine TaOx/CB catalysts for PEFC cathode application: Their oxygen reduction reaction kinetics

    KAUST Repository

    Seo, Jeongsuk; Anjum, Dalaver H.; Takanabe, Kazuhiro; Kubota, Jun; Domen, Kazunari

    2014-01-01

    Ultrafine TaOx nanoparticles were electrodeposited on carbon black (CB) powder in a nonaqueous Ta complex solution at room temperature, and the resultant TaOx/CB catalysts were assessed as oxygen reduction reaction (ORR) electrocatalysts for polymer electrolyte fuel cell (PEFC) cathodes. The Ta electrodeposition process was scaled up using a newly designed working electrode containing a CB dense layer, without introducing any binder such as the ionomer Nafion in the electrode for electrodeposition. The electrodeposited TaOx/CB powders were removed from the deposition electrode and subsequent H2 treatment at varying temperatures between 523 and 1073 K was attempted to increase the ORR performance. The TaOx/CB samples were characterized by SEM, STEM, XPS, and EELS measurements. XPS and EELS results indicated the reduced nature of the Ta species caused by the high-temperature treatment in H2, while STEM images clearly revealed that the TaOx particles aggregated as the treatment temperature increased. When the TaOx/CB catalyst, which was treated at 873 K for 2 h, was deposited on a glassy carbon substrate with Nafion ionomer, it resulted in the highest activity among the samples investigated, giving an onset potential of 0.95 VRHE at -2 μA cm-2 in a 0.1 M H2SO4 solution. Moreover, the long-term stability test with 10,000 cycles of the voltammetry only led to a 6% loss in the ORR currents, demonstrating the high stability of the TaOx/CB catalysts. Kinetic analysis by R(R)DE indicated that the four-electron transfer pathway in the ORR process was dominant for this TaOx/CB catalyst, and Tafel plots showed a slope corresponding to a one-electron reaction for the rate-determining step.

  12. Copper diffusion in TaN-based thin layers

    Energy Technology Data Exchange (ETDEWEB)

    Nazon, J. [Universite Montpellier II, Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, cc 1504, 34095 Montpellier Cedex 5 (France); Fraisse, B. [Laboratoire Structure, Proprietes et Modelisation des Solides (UMR 8580), Ecole Centrale de Paris, Grande Voie des Vignes, 92295 Chatenay-Malabry Cedex (France); Sarradin, J. [Universite Montpellier II, Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, cc 1504, 34095 Montpellier Cedex 5 (France); Fries, S.G. [SGF Scientific Consultancy, Arndt str.9, D-52064 Aachen (Germany); Tedenac, J.C. [Universite Montpellier II, Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, cc 1504, 34095 Montpellier Cedex 5 (France); Frety, N. [Universite Montpellier II, Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, cc 1504, 34095 Montpellier Cedex 5 (France)], E-mail: Nicole.Frety@univ-montp2.fr

    2008-07-15

    The diffusion of Cu through TaN-based thin layers into a Si substrate has been studied. The barrier efficiency of TaN/Ta/TaN multilayers of 150 nm in thickness has been investigated and is compared with that of TaN single layers. Thermal stabilities of these TaN-based thin layers against Cu diffusion were determined from in situ X-ray diffraction experiments, conducted in the temperature range of 773-973 K. The TaN/Ta/TaN barrier appeared to be more efficient in preventing Cu diffusion than the TaN single layer.

  13. Solar control on irradiated Ta2O2 thin films

    International Nuclear Information System (INIS)

    Baydogan, N. D.; Zayim, E. Oe.

    2007-01-01

    Thin films consisting of Ta 2 O 5 have been used in industry in applications related to thin-film capacitors, optical waveguides, and antireflection coatings on solar cells. Ta 2 O 5 films are used for several special applications as highly refractive material and show different optical properties depending on the deposition methods. Sol-gel technique has been used for the preparation of Ta 2 O 5 thin films. Ta 2 O 5 thin films were prepared by sol-gel proses on glass substrates to obtain good quality films. These films were exposed to gamma radiation from Co-60 radioisotope. Ta 2 O 5 coated thin films were placed against the source and irradiated for 8 different gamma doses; between 0.35 and 21.00 kGy at room temperature. Energetic gamma ray can affect the samples and change its colour. On the other hand some of the Ta 2 O 5 coated thin films were irradiated with beta radiation from Sr-90 radioisotope. The effect of gamma irradiation on the solar properties of Ta 2 O 5 films is compared with that of beta irradiation. The solar properties of the irradiated thin films differ significantly from those of the unirradiated ones. After the irradiation of the samples transmittance and reflectance are measured for solar light between 300 and 2100 nm, by using Perkin Elmer Lambda 9 UV/VIS/NIR Spectrophotometer. Change in the direct solar transmittance, reflectance and absorptance with absorbed dose are determined. Using the optical properties, the redistribution of the absorbed component of the solar radiation and the shading coefficient (SC) are calculated as a function of the convective heat-transfer coefficient. Solar parameters are important for the determination of the shading coefficient. When the secondary internal heat transfer factor (qi), direct solar transmittance (□ e ), and solar factor (g) are known, it is possible to determine shading coefficient via the dose rates. The shading coefficient changes as the dose rate is increased. In this study, the shading

  14. New ternary tantalum borides containing boron dumbbells: Experimental and theoretical studies of Ta{sub 2}OsB{sub 2} and TaRuB

    Energy Technology Data Exchange (ETDEWEB)

    Mbarki, Mohammed; Touzani, Rachid St.; Rehorn, Christian W.G.; Gladisch, Fabian C. [Institute of Inorganic Chemistry, RWTH Aachen University, D-52056 Aachen (Germany); Fokwa, Boniface P.T., E-mail: bfokwa@ucr.edu [Institute of Inorganic Chemistry, RWTH Aachen University, D-52056 Aachen (Germany); Department of Chemistry, University of California Riverside (UCR), Riverside, CA 92521 (United States)

    2016-10-15

    The new ternary transition metal-rich borides Ta{sub 2}OsB{sub 2} and TaRuB have been successfully synthesized by arc-melting the elements in a water-cooled crucible under an argon atmosphere. The crystal structures of both compounds were solved by single-crystal X-ray diffraction and their metal compositions were confirmed by EDX analysis. It was found that Ta{sub 2}OsB{sub 2} and TaRuB crystallize in the tetragonal Nb{sub 2}OsB{sub 2} (space group P4/mnc, no. 128) and the orthorhombic NbRuB (space group Pmma, no. 51) structure types with lattice parameters a=5.878(2) Å, c=6.857(2) Å and a=10.806(2) Å, b=3.196(1) Å, c=6.312(2) Å, respectively. Furthermore, crystallographic, electronic and bonding characteristics have been studied by density functional theory (DFT). Electronic structure relaxation has confirmed the crystallographic parameters while COHP bonding analysis indicates that B{sub 2}-dummbells are the strongest bonds in both compounds. Moreover, the formation of osmium dumbbells in Ta{sub 2}OsB{sub 2} through a Peierls distortion along the c-axis, is found to be the origin of superstructure formation. Magnetic susceptibility measurements reveal that the two phases are Pauli paramagnets, thus confirming the theoretical DOS prediction of metallic character. Also hints of superconductivity are found in the two phases, however lack of single phase samples has prevented confirmation. Furthermore, the thermodynamic stability of the two modifications of AMB (A=Nb, Ta; M =Ru, Os) are studied using DFT, as new possible phases containing either B{sub 4}- or B{sub 2}-units are predicted, the former being the most thermodynamically stable modification. - Graphical abstract: The two new ternary tantalum borides, Ta{sub 2}OsB{sub 2} and TaRuB, have been discovered. Their crystal structures contain boron dumbbells, which are the strongest bonds. Peirls distortion is found responsible for Os{sub 2}-dumbbells formation in Ta{sub 2}OsB{sub 2}. Ta{sub 2}OsB{sub 2} and

  15. Characterization of novel heat-responsive transcription factor (TaHSFA6e) gene involved in regulation of heat shock proteins (HSPs) - A key member of heat stress-tolerance network of wheat.

    Science.gov (United States)

    Kumar, Ranjeet R; Goswami, Suneha; Singh, Khushboo; Dubey, Kavita; Rai, Gyanendra K; Singh, Bhupinder; Singh, Shivdhar; Grover, Monendra; Mishra, Dwijesh; Kumar, Sanjeev; Bakshi, Suman; Rai, Anil; Pathak, Himanshu; Chinnusamy, Viswanathan; Praveen, Shelly

    2018-08-10

    Heat stress has an adverse effect on the quality and quantity of agriculturally important crops, especially wheat. The tolerance mechanism has not been explored much in wheat and very few genes/ TFs responsive to heat stress is available on public domain. Here, we identified, cloned and characterized a putative TaHSFA6e TF gene of 1.3 kb from wheat cv. HD2985. We observed an ORF of 368 aa with Hsf DNA binding signature domain in the amino acid sequence. Single copy number of TaHSFA6e was observed integrated in the genome of wheat. Expression analysis of TaHSFA6e under differential HS showed maximum transcripts in wheat cv. Halna (thermotolerant) in response to 38 °C for 2 h during pollination and grain-filling stages, as compared to PBW343, HD2329 and HD2985. Putative target genes of TaHSFA6e (HSP17, HSP70 and HSP90) showed upregulation in response to differential HS (30 & 38 °C, 2 h) during pollination and grain-filling stages. Small HSP17 was observed most triggered in Halna under HS. We observed increase in the catalase, guaiacol peroxidase, total antioxidant capacity (TAC), and decrease in the lipid peroxidation in thermotolerant cvs. (Halna, HD2985), as compared to thermosusceptible (PBW343, HD2329) under differential HS. Multiple stresses (heat - 38 °C, 2 h, and drought - 100 mL of 20% polyethylene Glycol 6000) during seedling stage of wheat showed positive correlation between the expression of TaHSFA6e, putative targets (HSP70, HSP90, HSP17) and TAC. Halna (thermotolerant) performed better, as compared to other contrasting cvs. TaHSFA6e TF can be used as promising candidate gene for manipulating the heat stress-tolerance network. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. DNA-methylation profiling of fetal tissues reveals marked epigenetic differences between chorionic and amniotic samples.

    Directory of Open Access Journals (Sweden)

    Christel Eckmann-Scholz

    Full Text Available Epigenetic mechanisms including DNA methylation are supposed to play a key role in fetal development. Here we have investigated fetal DNA-methylation levels of 27,578 CpG loci in 47 chorionic villi (CVS and 16 amniotic cell (AC samples. Methylation levels differed significantly between karyotypically normal AC and CVS for 2,014 genes. AC showed more extreme DNA-methylation levels of these genes than CVS and the differentially methylated genes are significantly enriched for processes characteristic for the different cell types sampled. Furthermore, we identified 404 genes differentially methylated in CVS with trisomy 21. These genes were significantly enriched for high CG dinucleotid (CpG content and developmental processes associated with Down syndrome. Our study points to major tissue-specific differences of fetal DNA-methylation and gives rise to the hypothesis that part of the Down syndrome phenotype is epigenetically programmed in the first trimester of pregnancy.

  17. TA-55 and Sigma Overview

    Energy Technology Data Exchange (ETDEWEB)

    Spearing, Dane Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Safeguards Science and Technology Group (NEN-1)

    2016-11-29

    These are slides from a facility overview presentation for visiting agencies to Los Alamos National Laboratory (LANL). The TA-55 Plutonium Facility (PF-4) is discussed in detail. PF-4 is a unique resource for US plutonium programs. The basic design is flexible and has adapted to changing national needs. It is a robust facility with strong safety and security implementation. It supports a variety of national programs. It will continue for many years into the future. Sigma is then discussed in detail, which handles everything from hydrogen to uranium. It has been in long term service to the Nation (nearly 60 years). It has a flexible authorization basis to handle almost the entire periodic table. It has a wide breadth of prototyping and characterization capabilities. It has integrated program and line management.

  18. Wobbling mode in 167Ta

    International Nuclear Information System (INIS)

    Hartley, D. J.; Ludington, A.; Pifer, R.; Seyfried, E. P.; Vanhoy, J. R.; Janssens, R. V. F.; Carpenter, M. P.; Lauritsen, T.; McCutchan, E. A.; Zhu, S.; Riedinger, L. L.; Darby, I. G.; Riley, M. A.; Aguilar, A.; Wang, X.; Chiara, C. J.; Chowdhury, P.; Lakshmi, S.; Tandel, S. K.; Tandel, U.

    2009-01-01

    The collective wobbling mode, the strongest signature for the rotation of a triaxial nucleus, has previously been seen only in a few Lu isotopes in spite of extensive searches in nearby isotopes. A sequence of transitions in the N=94 167 Ta nucleus exhibiting features similar to those attributed to the wobbling bands in the Lu nuclei has now been found. This band feeds into the πi 13/2 band at a relative energy similar to that seen in the established wobbling bands and its dynamic moment of inertia and alignment properties are nearly identical to the i 13/2 structure over a significant frequency range. Given these characteristics, it is likely that the wobbling mode has been observed for the first time in a nucleus other than Lu, making this collective motion a more general phenomenon.

  19. Road Safety Data, Collection, Transfer and Analysis DaCoTa. Workpackage 6, Driver Behaviour Monitoring through Naturalistic Driving: Deliverable 6.2: Part B: Sampling techniques and naturalistic driving study design.

    NARCIS (Netherlands)

    Commandeur, J.J.F.

    2015-01-01

    In this document we provide an overview of sampling and estimation methods that can be used to obtain population values of risk exposure data and safety performance indicators based on naturalistic driving study designs. More specifically, we discuss how to determine the optimal sample size required

  20. Electrochemical lithium and sodium intercalation into the tantalum-rich layered chalcogenides Ta2Se and Ta2Te3

    International Nuclear Information System (INIS)

    Lavela, P.; Tirado, J.L.

    1999-01-01

    Two-layered tantalum chalcogenides are evaluated as alkali metal intercalation hosts in lithium and sodium electrochemical cells. The metal-rich pseudo-two-dimensional solid Ta 2 Se shows a poor intercalation behaviour. Lithium reacts with the selenide by deintercalating selenium from the blocks of Ta-related b.c.c. structure leading to a collapse of the structure and the formation of tantalum metal. Sodium is reversibly intercalated to a limited extent leading to complex structural changes in the selenide, as revealed by electron diffraction. The two-dimensional telluride Ta 2 Te 3 allows a topotactic intercalation of lithium below 1 F/mol, while a more extended reaction leads to sample amorphization. The better intercalation behaviour of this solid can be related with the one-atom thick metal layer and the van der Waals gap separating tellurium atoms of successive layers. Sodium can be reversibly intercalated into Ta 2 Te 3 in sodium cells which show a good cycling behaviour. Exposure of the intercalated solid to water vapour allows the preparation of hydrated products with a monolayer or a bilayer of water molecules solvating sodium in the interlayer space. (orig.)

  1. Electric-field gradients at Ta donor impurities in Cr{sub 2}O{sub 3}(Ta) semiconductor

    Energy Technology Data Exchange (ETDEWEB)

    Darriba, G.N. [Departamento de Fisica and IFLP (CONICET-UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CC 67, 1900 La Plata (Argentina); Errico, L.A. [Departamento de Fisica and IFLP (CONICET-UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CC 67, 1900 La Plata (Argentina); Universidad Nacional del Noroeste Bonaerense (UNNOBA), Monteagudo 2772, 2700 Pergamino (Argentina); Munoz, E.L; Richard, D. [Departamento de Fisica and IFLP (CONICET-UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CC 67, 1900 La Plata (Argentina); Eversheim, P.D. [Helmholtz-Institut fuer Strahlen-und Kernphysik (H-ISKP), Universitaet Bonn, Nussallee 14-16, 53115 Bonn (Germany); Renteria, M., E-mail: renteria@fisica.unlp.edu.a [Departamento de Fisica and IFLP (CONICET-UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CC 67, 1900 La Plata (Argentina)

    2009-10-01

    We report perturbed-angular-correlation (PAC) experiments on {sup 181}Hf(->{sup 181}Ta)-implanted corundum Cr{sub 2}O{sub 3} powder samples in order to determine the magnitude and symmetry of the electric-field gradient (EFG) tensor at Ta donor impurity sites of this semiconductor. These results are analyzed in the framework of ab initio full-potential augmented-plane wave plus local orbitals (FP-APW+lo) calculations. The results are also compared with EFG results coming from PAC experiments in isomorphous alpha-Al{sub 2}O{sub 3} and alpha-Fe{sub 2}O{sub 3} doped with {sup 111}In->{sup 111}Cd and {sup 181}Hf->{sup 181}Ta tracers. This combined analysis enables us to quantify the magnitude of the lattice relaxations induced by the presence of the impurity and to determine the charge state of the impurity donor level introduced by Ta in the band gap of the semiconductor.

  2. NMR-ON of 182Ta and 183Ta in Fe

    International Nuclear Information System (INIS)

    Allsop, A.L.; Chaplin, D.H.; Murray, D.W.; Stone, N.J.

    1980-01-01

    Nuclear magnetic resonance has been observed on radioactive 182 Ta and 183 Ta oriented at low temperature in an Fe host, by detection of the change in spatial anisotropy of γ-rays emitted during nuclear decay. By measuring the resonant frequencies of 183 Ta in four different applied magnetic fields the nuclear magnetic moment and hyperfine field have been deduced. These are: vertical stroke μ( 183 Ta;I = 7/2) = 2.28(3)μsub(N) and Bsub(h)sub(f)(TaFe at 0 K) = -67.2(1.3)T. The sin of the ground state of 182 Ta has been determined as I = 3 by comparing resonance results with those obtained in a thermal equilibrium nuclear orientation study. The ratio of the resonant frequencies observed for 182 Ta and 183 Ta at one applied field value yields a magnetic moment for the former of vertical stroke μ( 182 Ta;I = 3) vertical stroke = 2.91(3)μsub(N). The spin lattice relaxation time for 183 TaFe (0.12 at% Ta) at 18 mK in an applied field of 0.5 T has been found to be 40(10)s. (orig.)

  3. Stoichiometry behavior of TaN, TaCN and TaC thin films produced by magnetron sputtering

    International Nuclear Information System (INIS)

    Vargas, M.; Castillo, H.A.; Restrepo-Parra, E.; De La Cruz, W.

    2013-01-01

    Thin films were synthesized in a magnetron sputtering system using a target of Ta with 99.99% purity and silicon substrates (1 1 1). The gases used for the film growth were (Ar + N 2 ), (Ar + CH 4 + N 2 ) and (Ar + CH 4 ) mixtures for TaN, TaCN and TaC, respectively. The substrate temperature increased from room temperature to 500 °C. The chemical composition and bonding configuration were examined using X-ray photoelectron spectroscopy (XPS), revealing Ta-N, Ta-C-N, Ta-C and C-C bonds. Moreover, the crystallographic structure was analyzed using X-ray diffraction (XRD), indicating the presence of (1 1 1) and (2 0 0) planes belonging to a face-centered cubic structure. The stoichiometry variation dependence on the CH 4 and N 2 flow was analyzed, and the influence of the substrate temperature on the coatings was investigated. Finally, scanning electron microscopy (SEM) was used to determine the evolution on the grain formation in the coatings as the substrate temperature increased.

  4. Stoichiometry behavior of TaN, TaCN and TaC thin films produced by magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, M. [Centro de Nanociencia y Nanotecnología, Universidad Nacional Autónoma de México, A.P. 2681, C.P. 22860, Ensenada, B.C. (Mexico); Castillo, H.A. [Centro de Enseñanza Técnica y Superior, CETYS Universidad, Campus Tijuana, Tijuana, B.C. (Mexico); Restrepo-Parra, E., E-mail: erestrepopa@unal.edu.co [Universidad Nacional de Colombia Sede Medellín Colombia, Facultad de Minas, Manizales (Colombia); De La Cruz, W. [Centro de Nanociencia y Nanotecnología, Universidad Nacional Autónoma de México, A.P. 2681, C.P. 22860, Ensenada, B.C. (Mexico)

    2013-08-15

    Thin films were synthesized in a magnetron sputtering system using a target of Ta with 99.99% purity and silicon substrates (1 1 1). The gases used for the film growth were (Ar + N{sub 2}), (Ar + CH{sub 4} + N{sub 2}) and (Ar + CH{sub 4}) mixtures for TaN, TaCN and TaC, respectively. The substrate temperature increased from room temperature to 500 °C. The chemical composition and bonding configuration were examined using X-ray photoelectron spectroscopy (XPS), revealing Ta-N, Ta-C-N, Ta-C and C-C bonds. Moreover, the crystallographic structure was analyzed using X-ray diffraction (XRD), indicating the presence of (1 1 1) and (2 0 0) planes belonging to a face-centered cubic structure. The stoichiometry variation dependence on the CH{sub 4} and N{sub 2} flow was analyzed, and the influence of the substrate temperature on the coatings was investigated. Finally, scanning electron microscopy (SEM) was used to determine the evolution on the grain formation in the coatings as the substrate temperature increased.

  5. Strengthening effect of nano-scaled precipitates in Ta alloying layer induced by high current pulsed electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Guangze; Luo, Dian; Fan, Guohua [School of Material Science & Engineering, Harbin Institute of Technology, Harbin 150001 (China); Ma, Xinxin, E-mail: maxin@hit.edu.cn [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Wang, Liqin [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2017-05-01

    Highlights: • Ta alloying layer are fabricated by magnetron sputtering and high current pulsed electron beam. • Nano-scaled TaC precipitates forms within the δ-Fe grain after tempering treatment. • The mean diameter of TaC particles is about 5–8 nm. • The hardness of alloying layer increased by over 50% after formation of nano-scaled TaC particle. - Abstract: In this study, the combination of magnetron sputtering and high current pulsed electron beam are used for surface alloying treatment of Ta film on high speed steel. And the Ta alloying layer is about 6 μm. After tempering treatment, TaC phase forms in Ta alloying layer when the treated temperature is over 823 K. Through the TEM and HRTEM observation, a large amount of nano-scaled precipitates (mean diameter 5–8 nm) form within the δ-Fe grain in Ta alloying layer after tempering treatment and these nano-scaled precipitates are confirmed as TaC particles, which contribute to the strengthening effect of the surface alloying layer. The hardness of tempered alloying layer can reach to 18.1 GPa when the treated temperature is 823 K which increase by 50% comparing with the untreated steel sample before surface alloying treatment.

  6. TaEDS1 genes positively regulate resistance to powdery mildew in wheat.

    Science.gov (United States)

    Chen, Guiping; Wei, Bo; Li, Guoliang; Gong, Caiyan; Fan, Renchun; Zhang, Xiangqi

    2018-04-01

    Three EDS1 genes were cloned from common wheat and were demonstrated to positively regulate resistance to powdery mildew in wheat. The EDS1 proteins play important roles in plant basal resistance and TIR-NB-LRR protein-triggered resistance in dicots. Until now, there have been very few studies on EDS1 in monocots, and none in wheat. Here, we report on three common wheat orthologous genes of EDS1 family (TaEDS1-5A, 5B and 5D) and their function in powdery mildew resistance. Comparisons of these genes with their orthologs in diploid ancestors revealed that EDS1 is a conserved gene family in Triticeae. The cDNA sequence similarity among the three TaEDS1 genes was greater than 96.5%, and they shared sequence similarities of more than 99.6% with the respective orthologs from diploid ancestors. The phylogenetic analysis revealed that the EDS1 family originated prior to the differentiation of monocots and dicots, and EDS1 members have since undergone clear structural differentiation. The transcriptional levels of TaEDS1 genes in the leaves were obviously higher than those of the other organs, and they were induced by Blumeria graminis f. sp. tritici (Bgt) infection and salicylic acid (SA) treatment. The BSMV-VIGS experiments indicated that knock-down the transcriptional levels of the TaEDS1 genes in a powdery mildew-resistant variety of common wheat compromised resistance. Contrarily, transient overexpression of TaEDS1 genes in a susceptible common wheat variety significantly reduced the haustorium index and attenuated the growth of Bgt. Furthermore, the expression of TaEDS1 genes in the Arabidopsis mutant eds1-1 complemented its susceptible phenotype to powdery mildew. The above evidences strongly suggest that TaEDS1 acts as a positive regulator and confers resistance against powdery mildew in common wheat.

  7. Influence of lead oxide addition on LnTiTaO 6 (Ln = Ce, Pr and Nd)

    Indian Academy of Sciences (India)

    The effect of PbO addition on the structural, processing and microwave dielectric properties of LnTiTaO6 (Ln = Ce, Pr and Nd) ceramics are reported. Conventional solid state ceramic route was used for the preparation of samples. Phase pure LnTiTaO6 (Ln = Ce, Pr and Nd) ceramics are prepared at a calcination ...

  8. Consolidation of W–Ta composites: Hot isostatic pressing and spark and pulse plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Dias, M., E-mail: marta.dias@itn.pt [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Guerreiro, F. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Correia, J.B. [LNEG, Laboratório Nacional de Energia e Geologia, Estrada do Paço do Lumiar, 1649-038 Lisboa (Portugal); Galatanu, A. [National Institute of Materials Physics, Atomistilor 105 bis Bucharest-Magurele, 077125 Ilfov (Romania); Rosiński, M. [Warsaw University of Technology, Faculty of Materials Science and Engineering, Warsaw (Poland); Monge, M.A.; Munoz, A. [Departamento de Física, Univerdidad Carlos III de Madrid, Avd. de la Universidad 30, 28911 Madrid (Spain); Alves, E. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Carvalho, P.A. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); CeFEMA, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)

    2015-10-15

    Highlights: • Consolidation of W–Ta composites using three techniques: HIP, SPS and PPS. • Comparison of consolidation methods in terms of W–Ta interdiffusion and densification. • Microstructure analysis in terms of oxides formation. - Abstract: Composites consisting of tantalum fiber/powder dispersed in a nanostructured W matrix have been consolidated by spark and pulse plasma sintering as well as by hot isostatic pressing. The microstructural observations revealed that the tungsten–tantalum fiber composites consolidated by hot isostatic pressing and pulse plasma sintering presented a continuous layer of Ta{sub 2}O{sub 5} phase at the W/Ta interfaces, while the samples consolidated by spark plasma sintering evidenced a Ta + Ta{sub 2}O{sub 5} eutectic mixture due to the higher temperature of this consolidation process. Similar results have been obtained for the tungsten–tantalum powder composites. A (W, Ta) solid solution was detected around the prior nanostructured W particles in tungsten–tantalum powder composites consolidated by spark and pulse plasma sintering. Higher densifications were obtained for composites consolidated by hot isostatic pressing and pulse plasma sintering.

  9. Microstructural characterization of Ta-Si alloy as cast; Caracterizacao microestrutural de ligas Ta-Si no estado bruto de fusao

    Energy Technology Data Exchange (ETDEWEB)

    Silva, A.A.A.P. da; Coelho, G.C.; Nunes, C.A.; Suzuki, P.A.; Borges, S.P.T., E-mail: antonioaaps@gmail.co [Universidade de Sao Paulo (EEL/USP), Lorena, SP (Brazil). Escola de Engenharia; Faria, M.I.S.T. [Centro Universitario de Volta Redonda (UNIFOA), RJ (Brazil)

    2010-07-01

    Recent experimental studies developed in our group involving systems containing transition metals and silicon differed from the phase diagrams actually accepted. The objective of this study is to experimentally re-evaluate the invariant reactions involving liquid phase of the binary Ta-Si. Samples with different compositions were melted in arc furnace with non-consumable tungsten electrode in the copper crucible cooled water under argon atmosphere and titanium getter, using materials of high purity (minimum purity of 99.5% Ta and 99.999% Si). The samples were melted four times to ensure the microstructural and compositional homogeneity. The microstructures of the samples as cast were characterized by scanning electron microscopy (SEM/EDS) and X-ray diffraction (XRD). The results of this analysis led to a proposal for the phase diagram of Ta-Si slightly different than the diagram currently accepted. (author)

  10. Anodic oxidation of Ta/Fe alloys

    International Nuclear Information System (INIS)

    Mato, S.; Alcala, G.; Thompson, G.E.; Skeldon, P.; Shimizu, K.; Habazaki, H.; Quance, T.; Graham, M.J.; Masheder, D.

    2003-01-01

    The behaviour of iron during anodizing of sputter-deposited Ta/Fe alloys in ammonium pentaborate electrolyte has been examined by transmission electron microscopy, Rutherford backscattering spectroscopy, glow discharge optical emission spectroscopy and X-ray photoelectron spectroscopy. Anodic films on Ta/1.5 at.% Fe, Ta/3 at.% Fe and Ta/7 at.% Fe alloys are amorphous and featureless and develop at high current efficiency with respective formation ratios of 1.67, 1.60 and 1.55 nm V -1 . Anodic oxidation of the alloys proceeds without significant enrichment of iron in the alloy in the vicinity of the alloy/film interface and without oxygen generation during film growth, unlike the behaviour of Al/Fe alloys containing similar concentrations of iron. The higher migration rate of iron species relative to that of tantalum ions leads to the formation of an outer iron-rich layer at the film surface

  11. Effects of a Ta interlayer on the phase transition of TiSi2 on Si(111)

    Science.gov (United States)

    Jeon, Hyeongtag; Jung, Bokhee; Kim, Young Do; Yang, Woochul; Nemanich, R. J.

    2000-09-01

    This study examines the effects of a thin Ta interlayer on the formation of TiSi2 on Si(111) substrate. The Ta interlayer was introduced by depositing Ta and Ti films sequentially on an atomically clean Si(111) substrate in an ultrahigh vacuum (UHV) system. Samples of 100 Å Ti with 5 and 10 Å Ta interlayers were compared to similar structures without an interlayer. After deposition, the substrates were annealed for 10 min, in situ, at temperatures between 500 and 750 °C in 50 °C increments. The TiSi2 formation with and without the Ta interlayer was analyzed with an X-ray diffractometer, Auger electron spectroscopy (AES), Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and a four-point probe. The AES analysis data showed a 1:2 ratio of Ti:Si in the Ti-silicide layer and indicated that the Ta layer remained at the interface between TiSi2 and the Si(111) substrate. The C 49-C 54 TiSi2 phase transition temperature was lowered by ˜200 °C. The C 49-C 54 TiSi2 phase transition temperature was 550 °C for the samples with a Ta interlayer and was 750 °C for the samples with no Ta interlayer. The sheet resistance of the Ta interlayered Ti silicide showed lower values of resistivity at low temperatures which indicated the change in phase transition temperature. The C 54 TiSi2 displayed different crystal orientation when the Ta interlayer was employed. The SEM and TEM micrographs showed that the TiSi2 with a Ta interlayer significantly suppressed the tendency to islanding and surface agglomeration.

  12. Resonances in odd-odd 182Ta

    Science.gov (United States)

    Brits, C. P.; Wiedeking, M.; Bello Garrote, F. L.; Bleuel, D. L.; Giacoppo, F.; Görgen, A.; Guttormsen, M.; Hadynska-Klek, K.; Hagen, T. W.; Ingeberg, V. W.; Kheswa, B. V.; Klintefjord, M.; Larsen, A. C.; Malatji, K. L.; Nyhus, H. T.; Papka, P.; Renstrøm, T.; Rose, S.; Sahin, E.; Siem, S.; Tveten, G. M.; Zeiser, F.

    2017-09-01

    Enhanced γ-decay on the tail of the giant electric dipole resonance, such as the scissors or pygmy resonances, can have significant impact on (n,γ) reaction rates. These rates are important input for modeling processes that take place in astrophysical environments and nuclear reactors. Recent results from the University of Oslo indicate the existence of a significant enhancement in the photon strength function for nuclei in the actinide region due to the scissors resonance. Further, the M1 strength distribution of the scissors resonances in rare earth nuclei has been studied extensively over the years. To investigate the evolution and persistence of the scissor resonance in other mass regions, an experiment was performed utilizing the NaI(Tl) γ-ray detector array (CACTUS) and silicon particle telescopes (SiRi) at the University of Oslo Cyclotron laboratory. Particle-γ coincidences from the 181Ta(d,p)182Ta and 181Ta(d,d')181Ta reactions were used to measure the nuclear level density and photon strength function of the well-deformed 181Ta and 182Ta systems, to investigate the existence of resonances below the neutron separation energy. Note to the reader: the title of this article has been corrected on September 19, 2017.

  13. Characterization of Rh films on Ta(110)

    International Nuclear Information System (INIS)

    Jiang, L.Q.; Ruckman, M.W.; Strongin, M.

    1989-01-01

    The surface and electronic structure of Rh films on Ta(110) up to several monolayers thick on Ta(110) are characterized by photoemission, Auger emission, low energy electron diffraction and low energy ion scattering. From the variation of the Rh Auger peak-to-peak intensity as a function of evaporation time, Rh/Ta(110) appears to grow in the Stranski-Krastanov mode at room temperature. However, the LEIS data show that the Rh adatoms begin to cluster on Ta(110) before growth of the monolayer is completed. Diffuse LEED scattering suggests that the Rh films are disordered. Photoemission shows that Rh chemisorption on Ta(110) generates two peaks located at 1.2 and 2. 5 eV binding energy during the initial phase of thin film growth (0 3.7 ML). Photoemission data for CO covered surfaces show that CO dissociates on the Rh/Ta(110) surface for Rh coverages less than 2.5 ML and also show that the Rh clusters develop at least one site capable of molecular CO adsorption above 0.3 ML Rh coverage. 38 refs., 5 figs

  14. Resonances in odd-odd 182Ta

    Directory of Open Access Journals (Sweden)

    Brits C.P.

    2017-01-01

    Full Text Available Enhanced γ-decay on the tail of the giant electric dipole resonance, such as the scissors or pygmy resonances, can have significant impact on (n,γ reaction rates. These rates are important input for modeling processes that take place in astrophysical environments and nuclear reactors. Recent results from the University of Oslo indicate the existence of a significant enhancement in the photon strength function for nuclei in the actinide region due to the scissors resonance. Further, the M1 strength distribution of the scissors resonances in rare earth nuclei has been studied extensively over the years. To investigate the evolution and persistence of the scissor resonance in other mass regions, an experiment was performed utilizing the NaI(Tl γ-ray detector array (CACTUS and silicon particle telescopes (SiRi at the University of Oslo Cyclotron laboratory. Particle-γ coincidences from the 181Ta(d,p182Ta and 181Ta(d,d'181Ta reactions were used to measure the nuclear level density and photon strength function of the well-deformed 181Ta and 182Ta systems, to investigate the existence of resonances below the neutron separation energy.

  15. Chemical Concentrations in Field Mice from Open-Detonation Firing Sites TA-36 Minie and TA-39 Point 6 at Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Fresquez, Philip R. [Los Alamos National Laboratory

    2011-01-01

    Field mice (mostly Peromyscus spp.) were collected at two open-detonation (high explosive) firing sites - Minie at Technical Area (TA) 36 and Point 6 at TA-39 - at Los Alamos National Laboratory in August of 2010 and in February of 2011 for chemical analysis. Samples of whole body field mice from both sites were analyzed for target analyte list elements (mostly metals), dioxin/furans, polychlorinated biphenyl congeners, high explosives, and perchlorate. In addition, uranium isotopes were analyzed in a composite sample collected from TA-36 Minie. In general, all constituents, with the exception of lead at TA-39 Point 6, in whole body field mice samples collected from these two open-detonation firing sites were either not detected or they were detected below regional statistical reference levels (99% confidence level), biota dose screening levels, and/or soil ecological chemical screening levels. The amount of lead in field mice tissue collected from TA-39 Point 6 was higher than regional background, and some lead levels in the soil were higher than the ecological screening level for the field mouse; however, these levels are not expected to affect the viability of the populations over the site as a whole.

  16. Establishing efficient cobalt based catalytic sites for oxygen evolution on a Ta3N5 photocatalyst

    KAUST Repository

    Nurlaela, Ela; Ould-Chikh, Samy; Llorens, Isabelle; Hazemann, Jean-louis; Takanabe, Kazuhiro

    2015-01-01

    In a photocatalytic suspension system with a powder semiconductor, the interface between the photocatalyst semiconductor and catalyst should be constructed to minimize resistance for charge transfer of excited carriers. This study demonstrates an in-depth understanding of pretreatment effects on the photocatalytic O2 evolution reaction (OER) activity of visible-light-responsive Ta3N5 decorated with CoOx nanoparticles. The CoOx/Ta3N5 sample was synthesized by impregnation followed by sequential heat treat-ments under NH3 flow and air flow at various temperatures. Various characterization techniques, including X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), scanning transmission electron microscopy (STEM), and X-ray photoelectron spec-troscopy (XPS), were used to clarify the state and role of cobalt. No improvement in photocatalytic activity for OER over the bare Ta3N5 was observed for the as-impregnated CoOx/Ta3N5, likely because of insufficient contact between CoOx and Ta3N5. When the sample was treated in NH3 at high temperature, a substantial improvement in the photocatalytic activity was observed. After NH3 treatment at 700 °C, the Co0-CoOx core-shell agglomerated cobalt structure was identified by XAS and STEM. No metallic cobalt species was evident after the photocatalytic OER, indicating that the metallic cobalt itself is not essential for the reaction. Accordingly, mild oxidation (200 °C) of the NH3-treated CoOx/Ta3N5 sample enhanced photocatalytic OER activity. Oxidation at higher temperatures drastically eliminated the photocatalytic activity, most likely because of unfavorable Ta3N5 oxidation. These results suggest that the intimate contact between cobalt species and Ta3N5 facilitated at high temperature is beneficial to enhancing hole transport and that the cobalt oxide provides electrocatalytic sites for OER.

  17. Establishing efficient cobalt based catalytic sites for oxygen evolution on a Ta3N5 photocatalyst

    KAUST Repository

    Nurlaela, Ela

    2015-08-05

    In a photocatalytic suspension system with a powder semiconductor, the interface between the photocatalyst semiconductor and catalyst should be constructed to minimize resistance for charge transfer of excited carriers. This study demonstrates an in-depth understanding of pretreatment effects on the photocatalytic O2 evolution reaction (OER) activity of visible-light-responsive Ta3N5 decorated with CoOx nanoparticles. The CoOx/Ta3N5 sample was synthesized by impregnation followed by sequential heat treat-ments under NH3 flow and air flow at various temperatures. Various characterization techniques, including X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), scanning transmission electron microscopy (STEM), and X-ray photoelectron spec-troscopy (XPS), were used to clarify the state and role of cobalt. No improvement in photocatalytic activity for OER over the bare Ta3N5 was observed for the as-impregnated CoOx/Ta3N5, likely because of insufficient contact between CoOx and Ta3N5. When the sample was treated in NH3 at high temperature, a substantial improvement in the photocatalytic activity was observed. After NH3 treatment at 700 °C, the Co0-CoOx core-shell agglomerated cobalt structure was identified by XAS and STEM. No metallic cobalt species was evident after the photocatalytic OER, indicating that the metallic cobalt itself is not essential for the reaction. Accordingly, mild oxidation (200 °C) of the NH3-treated CoOx/Ta3N5 sample enhanced photocatalytic OER activity. Oxidation at higher temperatures drastically eliminated the photocatalytic activity, most likely because of unfavorable Ta3N5 oxidation. These results suggest that the intimate contact between cobalt species and Ta3N5 facilitated at high temperature is beneficial to enhancing hole transport and that the cobalt oxide provides electrocatalytic sites for OER.

  18. Tribological properties of self-lubricating Ta-Cu films

    Science.gov (United States)

    Qin, Wen; Fu, Licai; Zhu, Jiajun; Yang, Wulin; Li, Deyi; Zhou, Lingping

    2018-03-01

    In this paper, Ta and TaCu films were deposited by using magnetron sputtering, and the tribological properties of the films against Si3N4 balls were investigated under the loads of 2 N and 5 N. The average grain sizes of both films are below 25 nm. Ta and TaCu films have approximate hardness. While the wear rate of TaCu film is much smaller than that of Ta film. Post-wear testing XRD, Raman and XPS revealed the formation of tantalum oxide on the worn surface of both Ta and TaCu films. Tantalum oxidation is effectively lubricating to reduce friction coefficient. So the friction coefficient of both Ta and TaCu film is about 0.45 under different applied loads. Meanwhile, the addition of Cu could increase the toughness of the film, and avoid the generation of wear debris, resulting in a significant increase in wear resistance.

  19. Early embryo achievement through isolated microspore culture in Citrus clementina Hort. ex Tan., cvs. ‘Monreal Rosso’ and ‘Nules’

    Directory of Open Access Journals (Sweden)

    Benedetta eChiancone

    2015-06-01

    Full Text Available Microspore embryogenesis is a method of achieving complete homozygosity from plants. It is particularly useful for woody species, like Citrus, characterized by long juvenility, a high degree of heterozygosity and often self-incompatibility. Anther culture is currently the method of choice for microspore embryogenesis in many crops. However, isolated microspore culture is a better way to investigate the processes at the cellular, physiological, biochemical and molecular levels as it avoids the influence of somatic anther tissue. To exploit the potential of this technique, it is important to separate the key factors affecting the process and, among them, culture medium composition and particularly the plant growth regulators and their concentration, as they can greatly enhance regeneration efficiency. To our knowledge, the ability of meta-Topolin, a naturally occurring aromatic cytokinin, to induce gametic embryogenesis in isolated microspores of Citrus has never been investigated. In this study, the effect of two concentrations of meta-Topolin instead of benzyladenine or zeatin in the culture medium was investigated in isolated microspore culture of two genotypes of Citrus. After eleven months of isolated microspore culture, for both genotypes and for all the four tested media, the microspore reprogramming and their sporophytic development was observed by the presence of multinucleated calli and microspore-derived embryos at different stages. Microsatellite analysis of parental and embryo samples was performed to determine the embryo alleles constitution of early embryos produced in all tested media, confirming their origin from microspores.To our knowledge, this is the first successful report of Citrus microspore embryogenesis with isolated microspore culture in Citrus, and in particular in Citrus clementina Hort. ex Tan, cvs. ‘Monreal Rosso’ and ‘Nules’.

  20. Diffusion barrier performance of novel Ti/TaN double layers for Cu metallization

    International Nuclear Information System (INIS)

    Zhou, Y.M.; He, M.Z.; Xie, Z.

    2014-01-01

    Highlights: • Novel Ti/TaN double layers offering good stability as a barrier against Cu metallization have been made achievable by annealing in vacuum. • The Ti/TaN double layers improved the adhesion with Cu thin films and showed good diffusion barrier between Cu and SiO 2 /Si up to the annealing condition. • The failure mechanism of Ti/TaN bi-layer is similar with the Cu/TaN/Si metallization system in which Cu atoms diffuse through the grain boundary of barrier and react with silicon to form Cu 3 Si. - Abstract: Novel Ti/TaN double layers offering good stability as a barrier against Cu metallization have been made achievable by annealing in vacuum better than 1 × 10 −3 Pa. Ti/TaN double layers were formed on SiO 2 /Si substrates by DC magnetron sputtering and then the properties of Cu/Ti/TaN/SiO 2 /Si film stacks were studied. It was found that the Ti/TaN double layers provide good diffusion barrier between Cu and SiO 2 /Si up to 750 °C for 30 min. The XRD, Auger and EDS results show that the Cu–Si compounds like Cu 3 Si were formed by Cu diffusion through Ti/TaN barrier for the 800 °C annealed samples. It seems that the improved diffusion barrier property of Cu/Ti/TaN/SiO 2 /Si stack is due to the diffusion of nitrogen along the grain boundaries in Ti layer, which would decrease the defects in Ti film and block the diffusion path for Cu diffusion with increasing annealing temperature. The failure mechanism of Ti/TaN bi-layer is similar to the Cu/TaN/Si metallization system in which Cu atoms diffuse through the grain boundary of barrier and react with silicon to form Cu 3 Si

  1. Effect of Ta content on martensitic transformation behavior of RuTa ultrahigh temperature shape memory alloys

    International Nuclear Information System (INIS)

    He Zhirong; Zhou Jingen; Furuya, Y.

    2003-01-01

    Effects of Ta content on martensitic transformation (MT) behavior of Ru 100-x Ta x (x=46-54 at.%) alloys have been investigated by differential scanning calorimetry, dilatometry, X-ray diffraction and optical microscopy. Ta content significantly affects the MT behavior of RuTa alloys. The one-stage reservible MT occurs in Ta-poor RuTa alloys with Ta content less than 49 at.%. The two-stage reservible MT takes place in near-equiatomic RuTa alloys. No reservible MT is observed in Ta-rich alloys with Ta content more then 52 at.% Ta. The MT temperatures and hysteresis of RuTa alloys decrease with increasing Ta content. The aged and thermal cycled processes are nearly no effect on the MT behavior of these alloys. The deforming way of RuTa alloys is twinning. The Ru 50 Ta 50 alloy is of the most excellent MT behavior among these RuTa alloys

  2. Synthesis and characterization of Cu{sub 3}TaIn{sub 3}Se{sub 7} and CuTa{sub 2}InTe{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Calderon, E.; Munoz-Pinto, M.; Duran-Pina, S.; Quintero, M.; Quintero, E.; Morocoima, M. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida (Venezuela); Delgado, G.E. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida (Venezuela); Romero, H. [Laboratorio de Magnetismo, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida (Venezuela); Briceno, J.M.; Fernandez, J. [Laboratorio de Analisis Quimico y Estructural (LAQUEM), Departamento de Fisica, Facultad de Ciencias, Merida (Venezuela); Grima-Gallardo, P.

    2008-07-15

    Polycrystalline samples of Cu{sub 3}TaIn{sub 3}Se{sub 7} and CuTa{sub 2}InTe{sub 4} were synthesized by the usual melt and anneal technique. X-ray powder diffraction showed a single phase behavior for both samples with tetragonal symmetry and unit cell parameter values a=5.794{+-}0.002 A, c=11.66{+-}0.01 A, c/a=2.01, V=391{+-}1 A{sup 3} and a=6.193{+-}0.001 A, c=12.400 {+-}0.002A, c/a=2.00, V=475{+-}1 A{sup 3}, respectively. Differential thermal analysis (DTA) measurements suggested a complicated behavior near the melting point with several thermal transitions observed in the heating and cooling runs. From the shape of the DTA peaks it was deduced that the melting is incongruent for both materials. Magnetic susceptibility measurements (zero-field cooling and field cooling) indicated an antiferromagnetic character with transition temperatures of T=70 K (Cu{sub 3}TaIn{sub 3}Se{sub 7}) and 42 K (CuTa{sub 2}InTe{sub 4}). A spin-glass transition was observed in Cu{sub 3}TaIn{sub 3}Se{sub 7} with T{sub f}{approx}50 K. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Synthesis and characterization of Cu3TaIn3Se7 and CuTa2InTe4

    International Nuclear Information System (INIS)

    Calderon, E.; Munoz-Pinto, M.; Duran-Pina, S.; Quintero, M.; Quintero, E.; Morocoima, M.; Delgado, G.E.; Romero, H.; Briceno, J.M.; Fernandez, J.; Grima-Gallardo, P.

    2008-01-01

    Polycrystalline samples of Cu 3 TaIn 3 Se 7 and CuTa 2 InTe 4 were synthesized by the usual melt and anneal technique. X-ray powder diffraction showed a single phase behavior for both samples with tetragonal symmetry and unit cell parameter values a=5.794±0.002 A, c=11.66±0.01 A, c/a=2.01, V=391±1 A 3 and a=6.193±0.001 A, c=12.400 ±0.002A, c/a=2.00, V=475±1 A 3 , respectively. Differential thermal analysis (DTA) measurements suggested a complicated behavior near the melting point with several thermal transitions observed in the heating and cooling runs. From the shape of the DTA peaks it was deduced that the melting is incongruent for both materials. Magnetic susceptibility measurements (zero-field cooling and field cooling) indicated an antiferromagnetic character with transition temperatures of T=70 K (Cu 3 TaIn 3 Se 7 ) and 42 K (CuTa 2 InTe 4 ). A spin-glass transition was observed in Cu 3 TaIn 3 Se 7 with T f ∼50 K. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. fs - kes ta on ja kust ta tuleb : [luuletused] / [Mesikepp, Indrek] fs

    Index Scriptorium Estoniae

    fs, pseud., 1971-

    2004-01-01

    Sisu: fs - kes ta on ja kust ta tuleb ; "töötasin arhiivis..." ; mustad puud mustas vees ; "on päev. on kylm. on öö..." ; "tead ju kyll..." ; "päiksest paistes päevad..." ; "mida sa teed kui on öö..."

  5. Density of salt melts containing KF, KCl, K2TaF7 and Ta2O5

    International Nuclear Information System (INIS)

    Agulyanskij, A.I.; Stangrit, P.T.; Konstantinov, V.I.

    1978-01-01

    The results of density measurements by hydrostatic weighing are given for molten K 2 TaF 7 - KF, K 2 TaF 7 -KCL, K 2 TaF 7 - KF - KCl and K 2 TaF 7 - KF - KCl - Ta 2 O 5 mixtures depending on their temperature and composition. The density of the last two systems was measured at compositions close to those of commercial electrolytes. The obtained specific volume - composition dependencies show that no interaction is taking place in the mixtures studied. It is, therefore, believed that, in the K 2 TaF 7 - KF melt, tantalum is mainly present as a complex TaF 7 2- ion, and, in the K 2 TaF 7 - KCl mlt, a certain amount of TaF 6 - ions may be formed along with TaF 7 2-

  6. Ta thickness-dependent perpendicular magnetic anisotropy features in Ta/CoFeB/MgO/W free layer stacks

    Energy Technology Data Exchange (ETDEWEB)

    Yang, SeungMo; Lee, JaBin; An, GwangGuk [Novel Functional Materials and Devices Lab, The Research Institute for Natural Science, Department of Physics, Hanyang University, Seoul 133-791 (Korea, Republic of); Kim, JaeHong [Division of Nano-Scale Semiconductor Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Chung, WooSeong [Nano Quantum Electronics Lab, Department of Electronics and Computer Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Hong, JinPyo, E-mail: jphong@hanyang.ac.kr [Novel Functional Materials and Devices Lab, The Research Institute for Natural Science, Department of Physics, Hanyang University, Seoul 133-791 (Korea, Republic of); Division of Nano-Scale Semiconductor Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2015-07-31

    We describe Ta underlayer thickness influence on thermal stability of perpendicular magnetic anisotropy in Ta/CoFeB/MgO/W stacks. It is believed that thermal stability based on Ta underlay is associated with thermally-activated Ta atom diffusion during annealing. The difference in Ta thickness-dependent diffusion behaviors was confirmed with X-ray photoelectron spectroscopy analysis. Along with a feasible Ta thickness model, our observations suggest that an appropriate seed layer choice is needed for high temperature annealing stability, a critical issue in the memory industry. - Highlights: • We observed changes in the diffusion behavior with regard to Ta seed layer thickness. • It was observed that a thinner Ta seed layer induced more annealing-stable features. • However, ultra-thin (0.75 nm) Ta shows unstable characteristics about the annealing process. • It was possibly due to a rugged interface of the Ta layer by the island growth process.

  7. EUSO-TA data and simulations

    Energy Technology Data Exchange (ETDEWEB)

    Bisconti, Francesca [Institut fuer Kernphysik (IKP), Karlsruher Institut fuer Technologie (KIT) (Germany); Collaboration: JEM-EUSO-Collaboration

    2016-07-01

    EUSO-TA is one of the fluorescence cosmic ray detector prototypes developed by the JEM-EUSO Collaboration. The prototype has two 1 m diameter Fresnel lenses and one photo detector module (PDM) as focal surface. The PDM consists of 36 multi-anode photomultiplier tubes from Hamamatsu. The prototype has been designed to get information about the calibration of the Fresnel lense system and the PDM, basic parts of the main space-based fluorescence detector under development. EUSO-TA is located at the Black Rock Mesa site of the Telescope Array project (Utah-USA) and works in parallel with the TA fluorescence detectors since February 2015. During its campaigns, EUSO-TA detects cosmic ray events, as well as the pulsed laser from the Central Laser Facility, necessary for the detector calibration. Also planes and stars signatures are well visible in the data, although out of the scientific purpose. The analysis of EUSO-TA data and the comparison of data with simulations will be shown.

  8. Characterization of Rh films on Ta(110)

    International Nuclear Information System (INIS)

    Jiang, L.Q.; Ruckman, M.W.; Strongin, M.

    1990-01-01

    The surface and electronic structure of Rh films on Ta(110) up to several monolayers thick on Ta(110) are characterized by photoemission, Auger emission, low-energy electron diffraction (LEED) and low-energy ion scattering (LEIS). From the variation of the Rh Auger peak-to-peak intensity as a function of evaporation time, Rh appears to grow in the Stranski--Krastanov mode at room temperature. However, the LEIS data show that the Rh adatoms begin to cluster on Ta(110) before growth of the monolayer is completed. Diffuse LEED scattering suggests that the Rh films are disordered. Photoemission shows that Rh chemisorption on Ta(110) generates two peaks located at -1.5 and -2.5 eV binding energy during the initial phase of thin-film growth (0 3.7 ML). CO dissociates on the Rh/Ta(110) surface for Rh coverages<2.5 ML and the surface develops a site capable of molecular CO adsorption above 0.3-ML Rh coverage

  9. Tritium diffusion in V, Nb and Ta

    International Nuclear Information System (INIS)

    Qi, Z.; Voelkl, J.; Laesser, R.; Wenzl, H.

    1983-01-01

    Gorsky-effect measurements of the diffusion coefficient of tritium (T) in V, Nb and Ta are reported. The measurements were performed at small T concentrations (less than about 1.4 at%), and in the temperature range from -140 0 C to 100 0 C. Comparison with results obtained for H and D shows an increase of the activation energy with increasing isotopic mass. For Nb and Ta, the pre-exponential factors are identical for all the isotopes, whereas for V this factor is appreciably larger for T than for H and D. The reduction of the relaxation strength in the presence of precipitation allows a rough determination of the solubility limit, which is found to be isotope independent for Nb and Ta. In V, the solubility limit for T is shifted slightly to lower temperatures. The H, D or T induced lattice expansion calculated from the relaxation strength shows no dependence on isotopic mass. (author)

  10. Uzurpacija zemljišta : Land usurpation

    OpenAIRE

    Jusuf Topoljak; Admir Mulahusić

    2011-01-01

    Rad na temu „Uzurpacija zemljišta“ izlaže problematiku uzurpacije zemljišta u Bosni i Hercegovini. Velika je uloga geodezije u rješavanju ovakvog, za društvo kompleksnog problema. U radu su date naznake definisanja i rješavanja problema uzurpiranog zemljišta. : Work on the topic of "land usurpation," exposes the issue of land usurpation in Bosnia and Herzegovina. Geodesy has a very important role in solving such a complex problem for the whole society. In this paper are given hints of defin...

  11. Uzurpacija zemljišta : Land usurpation

    Directory of Open Access Journals (Sweden)

    Jusuf Topoljak

    2011-12-01

    Full Text Available Rad na temu „Uzurpacija zemljišta“ izlaže problematiku uzurpacije zemljišta u Bosni i Hercegovini. Velika je uloga geodezije u rješavanju ovakvog, za društvo kompleksnog problema. U radu su date naznake definisanja i rješavanja problema uzurpiranog zemljišta. : Work on the topic of "land usurpation," exposes the issue of land usurpation in Bosnia and Herzegovina. Geodesy has a very important role in solving such a complex problem for the whole society. In this paper are given hints of defining and solving the problem of land usurpation.

  12. Photoluminescent properties of Pr3+ doped YTiAO6 (A= Nb&Ta) euxenite compounds

    Science.gov (United States)

    Venugopal, Meenu; Kumar, H. Padma

    2018-04-01

    Pr3+ doped YTiAO6 (A = Nb and Ta) compounds were prepared by conventional solid state ceramic route. X - ray diffraction studies of the samples confirmed the euxenite orthorhombic phase formation. Effect of Pr3+ doping on the optical and luminescence properties of YTiAO6 (A = Nb and Ta) were studied. The strong absorption in the UV region are due to the absorption by the host YTiAO6 (A = Nb and Ta) and all other peaks can be attributed to that of Pr3+. Host emission peaks are observed around 485 nm and 460 nm in all samples. The red emission observed at 614 nm in the doped samples corresponds to the 1D2 to 3H4 transition of Pr3+ ion. CIE colour coordinates and chromaticity values were also discussed.

  13. Mechanical properties and biocompatibility in alloy Ti-Ta system containing oxygen; Propriedades mecanicas e biocompatibilidades em ligas do sistema Ti-Ta contendo oxigenio

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, S.L.M.; Grandini, C.R., E-mail: samlea@fc.unesp.b [Universidade Estadual Paulista (UNESP), Bauru, SP (Brazil). Lab. de Anelasticidade e Biomateriais; Claro, A.P.R.A. [Universidade Estadual Paulista Julio de Mesquisa Filho (DMT/UNESP), Guaratingueta, SP (Brazil). Fac. de Engenharia. Dept. de Materiais e Tecnologia

    2010-07-01

    Due to the excellent properties such as corrosion resistance, good mechanical strength/density, good performance at high temperatures, Ti is very useful in the chemical industry and aerospace. Currently, their use has expanded to the field of biomaterials, due to its excellent biocompatibility and reduced elasticity modulus, favouring the production of orthopaedic and dental prostheses. Promising alloys are the Ti-Ta system and researches have been directed to describe and understand the behavior of this system. In this paper, samples of Ti-Ta alloys containing 8 and 16% (wt%) containing interstitial oxygen were prepared and characterized by density, xray diffraction, hardness, elasticity modulus measurements and in vitro cytotoxicity tests. (author)

  14. Detection and Molecular Characterization of Gemycircularvirus from Environmental Samples in Brazil.

    Science.gov (United States)

    da Silva Assis, Matheus Ribeiro; Vieira, Carmen Baur; Fioretti, Julia Monassa; Rocha, Mônica Simões; de Almeida, Pedro Ivo Neves; Miagostovich, Marize Pereira; Fumian, Tulio Machado

    2016-12-01

    Gemycircularvirus (GemyCV) is a group of viruses which has been recently proposed as a new viral genus detected in fecal and environmental samples around the world. GemyCVs have been detected in human blood, brain tissue, cerebrospinal fluid, and stool sample. In the present study, we demonstrate for the first time, through molecular detection and characterization, the presence of GemyCVs in environmental samples from Brazil. Our results show a percentage of positivity ranging from 69 (25/36) to 97 % (35/36) in river water samples collected in Manaus, Amazon region, and wastewater from a wastewater treatment plant located in Rio de Janeiro, respectively, revealing GemyCVs as an important environmental contaminant.

  15. DEPOSITION AND PROPERTY CHARACTERISATION OF TaN COATINGS DEPOSITED WITH DIFFERENT NITROGEN CONTENTS

    Directory of Open Access Journals (Sweden)

    Gilberto Bejarano Gaitán

    Full Text Available This study focused on the study of the influence of nitrogen content on the microstructure, chemical composition, mechanical and tribological properties of TaN coatings deposited on 420 stainless steel and silicon samples (100 using the magnetron sputtering technique. For the deposition of the TaN coatings an argon/nitrogen atmosphere was used, varying the nitrogen flux between 12% and 25%. For the coating characterization, scanning electron microscopy, energydispersive X-ray spectroscopy, atomic force microscopy, X-ray diffraction (XRD, micro-Raman spectroscopy, a microhardness tester, and a ball on disc tribometer were used. A refining of the columnar structure of the coatings, accompanied by a decrease in their thickness with the increased nitrogen content was observed. Initially, fcc-TaN (111 cubic phase growth was observed; this phase was changed to the fcc-TaN (200 above N2 12%. For contents greater than N2 18%, another nitrogen-rich phase was formed and the system tended towards amorphicity, particularly for a coating with N2 25% content. The TaN-1sample deposited with N2 12% in the gas mixture presented the highest micro-hardness value with 21.3GPa and the lowest friction coefficient and wear rate with 0.02 and 1.82x10-7 (mm³/Nm, respectively. From the obtained results, an important relationship between the microstructural, mechanical and tribological properties of the coated samples and their nitrogen content was observed.

  16. Project Ta-kos Outreach. Final Report.

    Science.gov (United States)

    Askew, Linda; And Others

    The Project Ta-kos Outreach program is an inservice training model designed to increase the probability that children (ages birth to 8) at risk for or with special needs and their families can access and receive appropriate services in order to remain an integral part of the community in which they reside. The program reflects an ecological…

  17. Miks ta nii teeb? / Kristiina Voolaid

    Index Scriptorium Estoniae

    Voolaid, Kristiina

    1999-01-01

    Kuidas mõtleb ruumikujundaja, kui ta valib vorme, värve, materjale ja esemeid? Sisearhitekt Kristiina Voolaid seletab oma mõtteid Kawe Plaza hoones asuvate Hüvitusfondi ja Werol Tehased kontorite ning noorele perekonnale sisustatud vanalinnakorteri näitel

  18. Investigation of the phase formation and dielectric properties of Bi7Ta3O18

    International Nuclear Information System (INIS)

    Chon, M.P.; Tan, K.B.; Khaw, C.C.; Zainal, Z.; Taufiq Yap, Y.H.; Chen, S.K.; Tan, P.Y.

    2014-01-01

    Highlights: • Synthesis condition of Bi 7 TaO 3 O 18 had been determined. • Recombination of intermediate BiTaO 4 and Bi 3 TaO 7 phases are required for the Bi 7 TaO 3 O 18 phase formation. • Stable material as confirmed by thermal and structural analyses. • Typical ferroelectric showing high dielectric constants and low losses. • Resonance and thermal activated polarisation processes are responsible for the excellent dielectric characteristic. -- Abstract: Polycrystalline Bi 7 Ta 3 O 18 was synthesised at the firing temperature of 950 °C over 18 h via conventional solid state method. It crystallised in a monoclinic system with space group C2/m, Z = 4 similar to that reported diffraction pattern in the Inorganic Crystal Structure Database (ICSD), 1-89-6647. The refined lattice parameters were a = 34.060 (3) Å, b = 7.618 (9) Å, c = 6.647 (6) Å with α = γ = 90° and β = 109.210 (7), respectively. The intermediate phase was predominantly in high-symmetry cubic structure below 800 °C and finally evolved into a low-symmetry monoclinic structured, Bi 7 Ta 3 O 18 at 950 °C. The sample contained grains of various shapes with different orientations in the size ranging from 0.33–22.70 μm. The elemental analysis showed the sample had correct stoichiometry with negligible Bi 2 O 3 loss. Bi 7 Ta 3 O 18 was thermally stable and it exhibited a relatively high relative permittivity, 241 and low dielectric loss, 0.004 at room temperature, ∼30 °C and frequency of 1 MHz

  19. Structure and physical properties of Cr_5B_3-type Ta_5Si_3 and Ta_5Ge_3

    International Nuclear Information System (INIS)

    Yuan, Fang; Forbes, Scott; Ramachandran, Krishna Kumar; Mozharivskyj, Yurij

    2015-01-01

    The Cr_5B_3-type Ta_5Si_3 phase was prepared by arc-melting, while the Cr_5B_3-type Ta_5Ge_3 one was synthesized through sintering at 1000 °C. X-ray single crystal diffraction was employed to elucidate their structure. According to the magnetization measurements, both Ta_5Si_3 and Ta_5Ge_3 are Pauli paramagnets, with Ta_5Ge_3 showing a Curie-Weiss-like paramagnetic behavior at low temperatures likely due to presence of paramagnetic impurity. Both Ta_5Si_3 and Ta_5Ge_3 display a very low electrical resistivity from 2 to 300 K. The resistivity is constant below 20 K, but displays a positive temperature coefficient above 20 K. Electronic structure calculations with the TB-LMTO-ASA method support the metallic character of the two phases and suggest that the bonding is optimized in both phases. - Highlights: • Synthesis of Cr_5B_3-type Ta_5Si_3 and Ta_5Ge_3 phases with high purity by arc-melting and sintering, respectively. • Magnetization data and electrical resistivity of the Cr_5B_3-type Ta_5Si_3 and Ta_5Ge_3 phases. • Crystal and electronic structure analysis for Ta_5Si_3 and Ta_5Ge_3 phase by X-ray diffraction and TB-LMTO-ASA calculations.

  20. Corrosion behaviour of welds and Ta in liquid lead

    Energy Technology Data Exchange (ETDEWEB)

    Heinzel, A., E-mail: Annette.heinzel@kit.edu; Müller, G.; Weisenburger, A.

    2016-02-15

    Four specimens, P91 welded by friction stir welding with and without post heat treatment, P91 electromagnetic pulse welded (EMP) and 14Cr ODS (explosive welding) were exposed at 550 °C for up to 2131 h to Pb containing 10{sup −6} wt% oxygen. After the exposure none of the samples showed dissolution attack, all were protected by an oxide layer at the surface. Nearly no effect on the oxidation due to welding was found in both friction stir welded specimens. Severe deformation and partial melting during explosive welding result in a slower oxide layer growth within the welding zone. The EMP sample was tested as delivered without post-heat treatment. No Pb penetrated into the tiny gap between the welded parts. After the test, the gap is filled up with oxides. Additionally, Ta, discussed as a pump impeller material, was exposed to Pb and PbBi at different temperatures (400–900 °C) and oxygen concentrations in liquid metal (saturated, 10{sup −6} wt%, 10{sup −8} wt% and reduced (<<10{sup −8} wt%). Only the Ta specimens exposed to Pb with highly reduced oxygen content showed nearly no attack. All the others exhibited oxide scale formation that becomes severe above 400 °C test temperature.

  1. New ternary tantalum borides containing boron dumbbells: Experimental and theoretical studies of Ta2OsB2 and TaRuB

    Science.gov (United States)

    Mbarki, Mohammed; Touzani, Rachid St.; Rehorn, Christian W. G.; Gladisch, Fabian C.; Fokwa, Boniface P. T.

    2016-10-01

    The new ternary transition metal-rich borides Ta2OsB2 and TaRuB have been successfully synthesized by arc-melting the elements in a water-cooled crucible under an argon atmosphere. The crystal structures of both compounds were solved by single-crystal X-ray diffraction and their metal compositions were confirmed by EDX analysis. It was found that Ta2OsB2 and TaRuB crystallize in the tetragonal Nb2OsB2 (space group P4/mnc, no. 128) and the orthorhombic NbRuB (space group Pmma, no. 51) structure types with lattice parameters a=5.878(2) Å, c=6.857(2) Å and a=10.806(2) Å, b=3.196(1) Å, c=6.312(2) Å, respectively. Furthermore, crystallographic, electronic and bonding characteristics have been studied by density functional theory (DFT). Electronic structure relaxation has confirmed the crystallographic parameters while COHP bonding analysis indicates that B2-dummbells are the strongest bonds in both compounds. Moreover, the formation of osmium dumbbells in Ta2OsB2 through a Peierls distortion along the c-axis, is found to be the origin of superstructure formation. Magnetic susceptibility measurements reveal that the two phases are Pauli paramagnets, thus confirming the theoretical DOS prediction of metallic character. Also hints of superconductivity are found in the two phases, however lack of single phase samples has prevented confirmation. Furthermore, the thermodynamic stability of the two modifications of AMB (A=Nb, Ta; M =Ru, Os) are studied using DFT, as new possible phases containing either B4- or B2-units are predicted, the former being the most thermodynamically stable modification.

  2. Study of radionuclides created by 181Ta(γ,xn yp) reactions for bremsstrahlung photons produced by 150-MeV electrons

    International Nuclear Information System (INIS)

    Miller, M.A.; Dickens, J.K.

    1991-12-01

    Ten radionuclides, including isomers, from 172 Ta to 180 Ta and 180m Hf were produced by photon interactions with a sample of elemental tantalum and measured by counting photons using a high-resolution detection system. Relative yields of these radionuclides were obtained. In addition, precision half lives were obtained for 175,176,180 Ta and 180m Hf. Those obtained for the three Ta isotopes agree with previously reported values. For 180m Hf, the present measurements resulted in a half life determination of 6.05±0.06 hr, or about 10% longer than the currently adopted value for this half life

  3. Direct observation of effective temperature of Ta atom in layer compound TaS2 by neutron resonance absorption spectrometer

    International Nuclear Information System (INIS)

    Tokuda, Koji; Kamiyama, Takashi; Kiyanagi, Yoshiaki; Moreh, R.; Ikeda, Susumu

    2001-01-01

    A neutron resonance absorption spectrometer, DOG has been installed at KENS, High Energy Accelerator Research Organization Neutron Source, which enables us to investigate the motions of a particular element by analyzing the line width of resonance absorption spectrum. We measured the temperature dependence of the effective temperature of Ta motion in TaS 2 as well as in Ta metal using DOG. The effective temperatures extracted from the observed absorption spectrum agree well with the calculated values from the phonon density of states of Ta metal over a wide temperature range of 10 to 300 K. We also succeeded in measuring both the angular dependence and the temperature dependence of effective temperatures of Ta in a layer compound TaS 2 . Based on the temperature dependence of the effective temperature, the partial phonon density of states of Ta in TaS 2 was discussed. (author)

  4. Study of dissolution factors of U, Th and Ta

    International Nuclear Information System (INIS)

    Santos, Maristela; Medeiros, Geiza; Zouain, Felipe; Cunha, Kenya Dias da; Pitassi, Gabriel; Lima, Cintia; Leite, Carlos Vieira Barros; Nascimento, Jose Eduardo; Dalia, Kely Cristina

    2009-01-01

    Air pollution can be a problem in industrial processes, but monitoring and controlling the aerosols in the work place is not enough to estimate the occupational risk due to dust particle inhalation. The solubility in lung fluid is considered to estimate this risk. The aim of this study is to determine in vitro specific dissolution parameters for thorium (Th), uranium (U) and tantalum (Ta) associated to crystal lattice of a niobium mineral (pyrochlore). Th, U and Ta dissolution factors in vitro were obtained using the Gamble solution (Simulant Lung Fluid, SLF), PIXE (Particle Induced X ray Emission) and alpha spectrometry as analytical techniques. Ta, Th and U are present in the pyrochlore crystal lattice as oxide; however they have shown different dissolution parameters. The rapid dissolution fraction (fr), rapid dissolution rate (λr); slow dissolution rate (fs) and slow dissolution fraction ((λs) measured for tantalum oxide were equal to 0.1, 0.45 d -1 and 0.00007 d -1 , respectively; for uranium oxide fr was equal to 0.05, (λr equal to 1.1 d -1 ; (λs equal to 0.000068 d -1 ; for thorium oxide fr was 0.025, (λr was 1.5 d -1 and (λs: 0.000065 d -1 . These results show that chemical behavior of these 3 compounds in the SLF could not be represented by the same parameter. The ratio of uranium concentration in urine and feces samples from workers exposed to pyrochlore dust particle was determined. These values agree with the theoretical values of estimated uranium concentration using specific parameters for uranium oxide present in pyrochlore. (author)

  5. The effect of low energy helium ion irradiation on tungsten-tantalum (W-Ta) alloys under fusion relevant conditions

    Science.gov (United States)

    Gonderman, S.; Tripathi, J. K.; Novakowski, T. J.; Sizyuk, T.; Hassanein, A.

    2017-08-01

    Currently, tungsten remains the best candidate for plasma-facing components (PFCs) for future fusion devices because of its high melting point, low erosion, and strong mechanical properties. However, continued investigation has shown tungsten to undergo severe morphology changes under fusion-like conditions. These results motivate the study of innovative PFC materials which are resistant to surface morphology evolution. The goal of this work is to examine tungsten-tantalum (W-Ta) alloys, a potential PFC material, and their response to low energy helium ion irradiation. Specifically, W-Ta samples are exposed to 100 eV helium irradiations with a flux of 1.15 × 1021 ions m-2 s-1, at 873 K, 1023 K, and 1173 K for 1 h duration. Scanning electron microscopy (SEM) reveals significant changes in surface deterioration due to helium ion irradiation as a function of both temperature and tantalum concentration in W-Ta samples. X-Ray Diffraction (XRD) studies show a slight lattice parameter expansion in W-Ta alloy samples compared to pure W samples. The observed lattice parameter expansion in W-Ta alloy samples (proportional to increasing Ta wt.% concentrations) reflect significant differences observed in the evolution of surface morphology, i.e., fuzz development processes for both increasing Ta wt.% concentration and target temperature. These results suggest a correlation between the observed morphology differences and the induced crystal structure change caused by the presence of tantalum. Shifts in the XRD peaks before and after 100 eV helium irradiation with a flux of 1.15 × 1021 ions m-2 s-1, 1023 K, for 1 h showed a significant difference in the magnitude of the shift. This has suggested a possible link between the atomic spacing of the material and the accumulated damage. Ongoing research is needed on W-Ta alloys and other innovative materials for their application as irradiation resistant materials in future fusion or irradiation environments.

  6. Electric Properties of NaTaO3 Obtained by Hydrothermal Method

    Science.gov (United States)

    Malaescu, Dan; Grozescu, Ioan; Sfirloaga, Paula; Vlazan, Paulina; Marin, Catalin N.

    2015-12-01

    Two samples of NaTaO3 perovskite materials were prepared by the standard hydrothermal method at the same reaction temperature (600 °C) but with different sintering times: 6 hours for sample S1 and 12 hours for sample S2. Using X-ray diffraction (XRD), it shows that samples S1 and S2 are mixtures of Na-Ta oxides (Ta2O5 and the prevailing phase NaTaO3). The scanning electron microscopy analysis (SEM), shows that the grains are connected each other in agglomerated clusters of size about few hundred nanometers. The frequency (f) dependencies of complex impedance, Z(f) = Z'(f) - i Z''(f) of the samples, over the frequency range 20 Hz - 2 MHz, at room temperature are presented. The real component Z' of the complex impedance decreases with increasing frequency and the imaginary component Z'' has two maximum corresponding to two relaxation processes. The results obtained from the complex impedance spectroscopy, Z''(Z') showed the appearance of two semicircles, corresponding to grain and grain boundary mechanism. Experimental results have been fitted with two parallel RC equivalent circuits connected in series and the parameters R and C have been evaluated.

  7. Effect of Modified Atmosphere Packaging on Postharvest Quality of Mango cvs. Sindhri and Sufaid Chaunsa During Storage

    Directory of Open Access Journals (Sweden)

    Omer Hafeez

    2016-12-01

    Full Text Available Modified atmosphere packaging (MAP technology is gaining popularity worldwide for its potential of extending shelf life of fresh produce with better fruit quality. Effect of MAP (using Xtend® bags, was investigated on postharvest storage life and quality of mango cvs Sindhri and Sufaid Chaunsa stored at 11°C with 80-85% RH for 4 and 5 weeks respectively, in comparison with un-bagged (control fruit. Uniform physiological mature fruit of Sindhri and Sufaid Chaunsa were harvested from a commercial mango orchard along with 4-5 cm long pedicel and were de-sapped in 0.5% lime solution (to avoid sap burn injury. Later on fruit were given cold water fungicidal dip (Sportak @ 0.5ml/L, Active Ingredient: Prochloraz followed by hot water treatment (52°C; 5 min. After shade drying and pre-cooling (11°C; 10-12 hours, fruit were packed according to the treatment combination and stored at 11°C. Fruit of both varieties were removed after 2, 3 and 4 weeks of storage followed by ripening at 24±2°C with an additional removal after 5 weeks for Sufaid Chaunsa only. Fruit quality was evaluated for various bio-chemical, organoleptic and physical parameters at two stages of ripening (at removal day and at final ripening day. Fruit of both varieties stored in MAP exhibited better firmness and retained green colour as compared to un-bagged fruit. Quality of fruit subjected to postharvest fungicidal application and hot water treatments and stored under MAP at 11°C showed better peel colour development and less disease development. Moreover, storage durations and post storage ripening stages significantly affected fruit peel colour, textural softness and disease development. Further, cv. Sindhri showed better storage potential with lower disease incidence as compared to cv. Sufaid Chaunsa which warrants further studies on disease control aspects.

  8. The Ca2+ induced two-component system, CvsSR regulates the Type III secretion system and the extracytoplasmic function sigma-factor AlgU in Pseudomonas syringae pv. tomato DC3000.

    Science.gov (United States)

    Fishman, Maxwell R; Zhang, Johnson; Bronstein, Philip A; Stodghill, Paul; Filiatrault, Melanie J

    2017-12-20

    Two-component systems (TCSs) of bacteria regulate many different aspects of the bacterial life cycle including pathogenesis. Most TCSs remain uncharacterized with no information about the signal(s) or regulatory targets and/or role in bacterial pathogenesis. Here, we characterized a TCS in the plant-pathogenic bacterium Pseudomonas syringae pv. tomato DC3000 ( Pto ) composed of the histidine kinase, CvsS, and the response regulator, CvsR. CvsSR is necessary for virulence of Pto , since ΔcvsS and ΔcvsR strains produced fewer symptoms and demonstrated reduced growth on multiple hosts as compared to WT. We discovered that expression of cvsSR is induced by Ca 2+ concentrations found in leaf apoplastic fluid. Thus, Ca 2+ can be added to the list of signals that promote pathogenesis of Pto during host colonization. Through chromatin immunoprecipitation followed by next generation sequencing (ChIP-seq) and global transcriptome analysis (RNA-seq) we discerned the CvsR regulon. CvsR directly activated expression of the type III secretion system regulators, hrpR and hrpS , that regulates Pto virulence in a type III secretion system dependent manner. CvsR also indirectly repressed transcription of the extracytoplasmic sigma factor algU and production of alginate. Phenotypic analysis determined that CvsSR inversely regulated biofilm formation, swarming motility, and cellulose production in a Ca 2+ -dependent manner. Overall, our results show that CvsSR is a key regulatory hub critical for interaction with host plants. Importance Pathogenic bacteria must be able to react and respond to the surrounding environment, make use of available resources, and avert or counter host immune responses. Often, these abilities rely on two-component systems (TCSs) composed of interacting proteins that modulate gene expression. We identified a TCS in the plant-pathogenic bacterium Pseudomonas syringae that responds to the presence of calcium, which is an important signal during the plant

  9. International collaboration on CESR-TA program

    International Nuclear Information System (INIS)

    Flanagan, John; Suetsugu, Yusuke

    2009-01-01

    An international collaboration on the CESR-TA (Cornell Electron Storage Ring-Test Accelerator) program, which is a program to investigate electron cloud instability (ECI) issues in the positron damping ring of the ILC (International Linear-Collider), is currently underway a Cornell University, KEK is supporting the program through the development of an X-ray beam profile monitor system to measure the extremely small beam size, and through the development of clearing electrodes to mitigate the ECI. (author)

  10. Soil fauna in forest and coffee plantations from the Sierra Nevada de Santa Mar ta, Colombia

    International Nuclear Information System (INIS)

    Camero R, Edgar

    2002-01-01

    Two research stations (M inca, 700 m altitude and Maria Ter esa, 790 m altitude) were established in the Sierra Nevada de Santa Mar ta in places to study the soil fauna associated with forest and coffee plantations. Soil fauna was collected using pitfall and Bailer's traps. Samples were taken from litter as well as from horizons 0, A and B. individuals collected were identified to family level. Diversity, abundance and frequency indexes were used to compare fauna composition at both sites. Significant differences were found between the two research sites as well as with data from other high altitude forest in the Sierra Nevada de Santa Mar ta

  11. Mechanical properties and biocompatibility in alloy Ti-Ta system containing oxygen

    International Nuclear Information System (INIS)

    Ruiz, S.L.M.; Grandini, C.R.; Claro, A.P.R.A.

    2010-01-01

    Due to the excellent properties such as corrosion resistance, good mechanical strength/density, good performance at high temperatures, Ti is very useful in the chemical industry and aerospace. Currently, their use has expanded to the field of biomaterials, due to its excellent biocompatibility and reduced elasticity modulus, favouring the production of orthopaedic and dental prostheses. Promising alloys are the Ti-Ta system and researches have been directed to describe and understand the behavior of this system. In this paper, samples of Ti-Ta alloys containing 8 and 16% (wt%) containing interstitial oxygen were prepared and characterized by density, xray diffraction, hardness, elasticity modulus measurements and in vitro cytotoxicity tests. (author)

  12. Field dependence of magnetic viscosity of CoCrTa in-plane media

    NARCIS (Netherlands)

    Phan le kim, P.L.K.; Lodder, J.C.; Popma, T.J.A.

    1999-01-01

    In this paper we will present a study of magnetic viscosity as a function of applied field of CoCrTa/Cr in-plane media. The viscosity versus applied field curves (viscosity curves) of the samples exhibit a sharp peak at remanence coercivity (Hcr). Their activation volume was found to be close to the

  13. Thin TaC layer produced by ion mixing

    DEFF Research Database (Denmark)

    Barna, Árpád; Kotis, László; Pécz, Béla

    2012-01-01

    in strongly asymmetric ion mixing; the carbon was readily transported to the Ta layer, while the reverse process was much weaker. Because of the asymmetrical transport the C/TaC interface remained sharp independently from the applied fluence. The carbon transported to the Ta layer formed Ta......Ion-beam mixing in C/Ta layered systems was investigated. C 8nm/Ta 12nm and C 20nm/Ta 19nm/C 20nm layer systems were irradiated by Ga+ ions of energy in the range of 2–30keV. In case of the 8nm and 20nm thick C cover layers applying 5–8keV and 20–30keV Ga+ ion energy, respectively resulted...

  14. 75 FR 43556 - TA-W-73,381, MT Rail Link, Inc., Missoula, MT; TA-W-73,381A, Billings, MT; TA-W-73,381B, Laurel...

    Science.gov (United States)

    2010-07-26

    ... DEPARTMENT OF LABOR Employment and Training Administration TA-W-73,381, MT Rail Link, Inc., Missoula, MT; TA-W-73,381A, Billings, MT; TA-W-73,381B, Laurel, MT; TA-W-73,381C, Livingston, MT; TA-W-73... Helena, Montana. The amended notice applicable to TA-W-73,381 is hereby issued as follows: All workers of...

  15. Composition analysis of Ta-W alloy using NAA and EDXRF techniques

    International Nuclear Information System (INIS)

    Swain, K.K.; Remya Devi, P.S.; Chavan, Trupti A.; Verma, R.; Reddy, A.V.R.

    2015-01-01

    Tantalum-Tungsten (Ta-W) alloy is a high strength alloy and is used in corrosion resistant chemical process equipment's including heat exchangers, condensers, heating and cooling coils and reaction vessels. Ta-W alloy is also used as ion extraction plate during laser Isotope separation of uranium and hence the composition is critical for its optimal application. The composition of the alloy was determined by neutron activation analysis (NAA) and energy dispersive X-ray fluorescence spectrometry (EDXRF) techniques. Ta-W alloy sample was received from Nuclear Fuel Complex (NFC), Hyderabad. For NAA, samples (50 - 500 mg) were sealed in polyethylene. High purity Ta foil (30 - 40 mg) and W foil (10 - 20 mg) were packed and used as comparators. Samples and standards were irradiated in the graphite reflector position of Advanced Heavy Water Reactor Critical Facility (AHWR CF) reactor, BARC, Mumbai for 4 hours. After suitable decay period, radioactivity assay was carried out using a 45% relative efficiency high purity germanium (HPGe) detector coupled to MCA with 8 k conversion gain

  16. Energy-beam processing studies on Ta/U and Ir/Ta systems

    International Nuclear Information System (INIS)

    Kaufmann, E.N.; Peercy, P.S.; Jacobson, D.C.; Draper, C.W.; Huegel, F.J.; Echer, C.J.; Makowiecki, D.M.; Balser, J.D.

    1983-01-01

    Films of Ta metal on uranium and of Ir metal on tantalum have been irradiated and melted by pulses from Q-switched Ruby and frequency-doubled Nd:YAG lasers to investigate the nature of the resulting mixtures in light of the very different binary-phase diagrams of the two systems. In addition, a two-phase Ir-Ta alloy has been surface-processed with CW CO 2 -laser radiation and with an electron beam in order to study microstructure refinement and test the advantage of using alloys as opposed to film-on-substrate combinations for the development of claddings

  17. 78 FR 28627 - TA-W-80,340; TA-W-80,340A; TA-W-80,340B

    Science.gov (United States)

    2013-05-15

    ...] Bush Industries, Inc., Mason Drive Facility, Including On-Site Leased Workers From Morris Security...., Mason Drive Facility, Jamestown, New York (TA-W-80,340) and Bush Industries, Inc., Allen Street Facility... applicable to TA-W-80,340 is hereby issued as follows: All workers of Bush Industries, Inc., Mason Drive...

  18. Limited Range Sesame EOS for Ta

    Energy Technology Data Exchange (ETDEWEB)

    Greeff, Carl William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Crockett, Scott [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rudin, Sven Peter [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Burakovsky, Leonid [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-30

    A new Sesame EOS table for Ta has been released for testing. It is a limited range table covering T ≤ 26, 000 K and ρ ≤ 37.53 g/cc. The EOS is based on earlier analysis using DFT phonon calculations to infer the cold pressure from the Hugoniot. The cold curve has been extended into compression using new DFT calculations. The present EOS covers expansion into the gas phase. It is a multi-phase EOS with distinct liquid and solid phases. A cold shear modulus table (431) is included. This is based on an analytic interpolation of DFT calculations.

  19. Measurement of recoil nuclei of Ta photofission

    International Nuclear Information System (INIS)

    Amroyan, K.A.; Barsegyan, S.A.; Demekhina, N.A.

    1993-01-01

    The results of measuring the characteristics of nuclei leaving the Ta target bombarded by 4,5 GeV bremsstrahlung photons are presented. The thick-target-trap technique is used. The radioactive residual nuclei were detected by the induced activity with the help of the Ge(Li) detector. The forward-backward nucleus ratio is measured, and the kinematical characteristics are calculated in the framework of the two-step vector model of velocities. The data analysis and systematization is carried out in comparison with the results of hardon-nuclear interactions

  20. TA-2 Water Boiler Reactor Decommissioning Project

    International Nuclear Information System (INIS)

    Durbin, M.E.; Montoya, G.M.

    1991-06-01

    This final report addresses the Phase 2 decommissioning of the Water Boiler Reactor, biological shield, other components within the biological shield, and piping pits in the floor of the reactor building. External structures and underground piping associated with the gaseous effluent (stack) line from Technical Area 2 (TA-2) Water Boiler Reactor were removed in 1985--1986 as Phase 1 of reactor decommissioning. The cost of Phase 2 was approximately $623K. The decommissioning operation produced 173 m 3 of low-level solid radioactive waste and 35 m 3 of mixed waste. 15 refs., 25 figs., 3 tabs

  1. Oxidative addition of diphenyl disulfide across a Ta=Ta bond. Preparation and characterization of [TaCl3(Me2S)]2(μ-SPh)2

    International Nuclear Information System (INIS)

    Campbell, G.C.; Canich, J.A.M; Cotton, F.A.; Duraj, S.A.; Haw, J.F.

    1986-01-01

    The tantalum complex (SMe 2 )Cl 2 Ta(μ-Cl) 2 (μ-SMe 2 )TaCl 2 (SMe 2 ), possessing a sigma 2 π 2 Ta=Ta double bond, reacts readily with PhSSPh to give (SMe 2 )Cl 3 Ta(μ-SPh) 2 TaCl 2 (SMe 2 ). In this reaction, the starting material loses the bridging SMe 2 ligand and two chloride bridges are broken while only two new SPh bridges are formed in the final product. This oxidative-addition reaction of the S-S single bond to the Ta=Ta double bond converts the face-sharing bioctahedron structure of the starting compound to an edge-sharing bioctahedron structure in the final dimer, with concomitant change of the oxidation state of tantalum from III to IV. The product is the first example of a d 1 -d 1 ditantalum thiolate-bridged dimer. Important structural data for (SMe 2 )Cl 3 Ta(μ-SPh) 2 TaCl 3 (SMe 2 ), which has an inversion center, are determined. The new compound crystallizes in the monoclinic space group C2/c with a = 17.934 (5) A, b = 12.445 (4) A, c = 11.705 (4) A, β = 92.50 (3) 0 , V = 2610 (2) A 3 , and Z = 4. Solid-state 13 C NMR spectroscopy with cross polarization and magic-angle spinning (CP/MAS) at 28 and -103 0 C provides evidence that this compound is diamagnetic. 12 references, 3 figures, 4 tables

  2. Laser stimulated third harmonic generation studies in ZnO-Ta2O5-B2O3 glass ceramics entrenched with Zn3Ta2O8 crystal phases

    Science.gov (United States)

    Siva Sesha Reddy, A.; Jedryka, J.; Ozga, K.; Ravi Kumar, V.; Purnachand, N.; Kityk, I. V.; Veeraiah, N.

    2018-02-01

    In this study zinc borate glasses doped with different concentrations Ta2O5 were synthesized and were crystallized by heat treatment for prolonged times. The samples were characterized by XRD, SEM, IR and Raman spectroscopy techniques. The SEM images of the crystallized samples have indicated that the samples contain randomly distributed crystal grains with size ∼1 μm entrenched in the residual amorphous phase. XRD studies have exhibited diffraction peaks identified as being due to the reflections from (1 1 1) planes of monoclinic Zn3Ta2O8 crystal phase that contains intertwined tetrahedral zinc and octahedral tantalate structural units. The concentration of such crystal phases in the bulk samples is observed to increase with increase of Ta2O5 up to 3.0 mol%. The IR and Raman spectroscopy studies have confirmed the presence of ZnO4 and TaO6 structural units in the glass network in addition to the conventional borate structural units. For measuring third harmonic generation (THG) in the samples, the samples were irradiated with 532 nm laser beam and the intensity of THG of probing beam (Nd:YAG λ = 1064 nm 20 ns pulsed laser (ω)) is measured as a function of fundamental beam power varying up to 200 J/m2. The intensity of THG is found to be increasing with increase of fundamental beam power and found to be the maximal for the glass crystallized with 3.0 mol% of Ta2O5. The intensity of THG of the ceramicized samples is found to be nearly 5 times higher with respect to that of pre-crystallized samples. The generation of 3ω is attributed to the perturbation/interaction between Zn3Ta2O8 anisotropic crystal grains and the incident probing beam.

  3. Social shaping of technology in TA and HTA

    DEFF Research Database (Denmark)

    Clausen, Christian; Yoshinaka, Yutaka

    2004-01-01

    The paper discusses how the social shaping of technology (SST) approach may be useful in understanding the role played by technology assessment within the context of technological development and change. It is proposed that an SST perspective on TA (or HTA) yields particular insight, regardless...... of whether or not the TA activity bases itself on a social shaping understanding of technology. This is because SST addresses the socially negotiated character of technological development, where TA itself may be construed as an element influencing the process of such negotiation. At the same time, TA...... is a construction, that is, itself a product of negotiations involving social actors. Thus, an understanding that TA is socially shaped, and is involved in the shaping of technology, opens up for a perspective on TA as both entailing constraints and enablements within the context of the particular agenda...

  4. Procedure-related risk of miscarriage following amniocentesis and chorionic villus sampling: a systematic review and meta-analysis.

    Science.gov (United States)

    Akolekar, R; Beta, J; Picciarelli, G; Ogilvie, C; D'Antonio, F

    2015-01-01

    To estimate procedure-related risks of miscarriage following amniocentesis and chorionic villus sampling (CVS) based on a systematic review of the literature and a meta-analysis. A search of MEDLINE, EMBASE, CINHAL and The Cochrane Library (2000-2014) was performed to review relevant citations reporting procedure-related complications of amniocentesis and CVS. Only studies reporting data on more than 1000 procedures were included in this review to minimize the effect of bias from smaller studies. Heterogeneity between studies was estimated using Cochran's Q, the I(2) statistic and Egger bias. Meta-analysis of proportions was used to derive weighted pooled estimates for the risk of miscarriage before 24 weeks' gestation. Incidence-rate difference meta-analysis was used to estimate pooled procedure-related risks. The weighted pooled risks of miscarriage following invasive procedures were estimated from analysis of controlled studies including 324 losses in 42 716 women who underwent amniocentesis and 207 losses in 8899 women who underwent CVS. The risk of miscarriage prior to 24 weeks in women who underwent amniocentesis and CVS was 0.81% (95% CI, 0.58-1.08%) and 2.18% (95% CI, 1.61-2.82%), respectively. The background rates of miscarriage in women from the control group that did not undergo any procedures were 0.67% (95% CI, 0.46-0.91%) for amniocentesis and 1.79% (95% CI, 0.61-3.58%) for CVS. The weighted pooled procedure-related risks of miscarriage for amniocentesis and CVS were 0.11% (95% CI, -0.04 to 0.26%) and 0.22% (95% CI, -0.71 to 1.16%), respectively. The procedure-related risks of miscarriage following amniocentesis and CVS are much lower than are currently quoted. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.

  5. Microstructure and superplasticity of TA15 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Q.J., E-mail: cruzesun@nchu.edu.cn; Wang, G.C.

    2014-06-01

    Superplasticity of TA15 alloy was investigated by constant strain rate tensile method in this work. In order to enhance superplasticity, thermo-mechanical techniques were applied for refining the grains of the alloy first. The superplastic tensile tests were carried out on a SANS CMT4104 electronic tensile testing machine at temperatures ranging from 780 to 950 °C and strain rates from 3.3×10{sup −4} to 1.1×10{sup −2} s{sup −1}. The tensile elongation-to-failure values between 188% and 1074% were obtained. Microstructure evolution after superplastic deformation was also analyzed by optical microscope (OM) and transmission electron microscope (TEM). The micrographs show that the grains were coarsened after deformation, and α→β phase transformation took place at 950 °C, which resulted in the worst superplasticity. Extensive strain hardening stages were observed in the true stress–strain curves due to high dense dislocations in the thermo-mechanically processed alloy and dynamic grain growth during superplastic deformation. The strain rate sensitivity m and the activation energy values at various deformation conditions were calculated, respectively. Based on an analysis of the above studies, it may be inferred that grain boundary sliding (GBS) in TA15 alloy is accommodated by grain boundary diffusion at high temperatures and low strain rates, and the accommodation process involves dislocation glide creep at low temperatures and high strain rates.

  6. Accident selection methodology for TA-55 FSAR

    International Nuclear Information System (INIS)

    Letellier, B.C.; Pan, P.Y.; Sasser, M.K.

    1995-01-01

    In the past, the selection of representative accidents for refined analysis from the numerous scenarios identified in hazards analyses (HAs) has involved significant judgment and has been difficult to defend. As part of upgrading the Final Safety Analysis Report (FSAR) for the TA-55 plutonium facility at the Los Alamos National Laboratory, an accident selection process was developed that is mostly mechanical and reproducible in nature and fulfills the requirements of the Department of Energy (DOE) Standard 3009 and DOE Order 5480.23. Among the objectives specified by this guidance are the requirements that accident screening (1) consider accidents during normal and abnormal operating conditions, (2) consider both design basis and beyond design basis accidents, (3) characterize accidents by category (operational, natural phenomena, etc.) and by type (spill, explosion, fire, etc.), and (4) identify accidents that bound all foreseeable accident types. The accident selection process described here in the context of the TA-55 FSAR is applicable to all types of DOE facilities

  7. Total neutron cross section for 181Ta

    Directory of Open Access Journals (Sweden)

    Schilling K.-D.

    2010-10-01

    Full Text Available The neutron time of flight facility nELBE, produces fast neutrons in the energy range from 0.1 MeV to 10 MeV by impinging a pulsed relativistic electron beam on a liquid lead circuit [1]. The short beam pulses (∼10 ps and a small radiator volume give an energy resolution better than 1% at 1 MeV using a short flight path of about 6 m, for neutron TOF measurements. The present neutron source provides 2 ⋅ 104  n/cm2s at the target position using an electron charge of 77 pC and 100 kHz pulse repetition rate. This neutron intensity enables to measure neutron total cross section with a 2%–5% statistical uncertainty within a few days. In February 2008, neutron radiator, plastic detector [2] and data acquisition system were tested by measurements of the neutron total cross section for 181Ta and 27Al. Measurement of 181Ta was chosen because lack of high quality data in an anergy region below 700 keV. The total neutron cross – section for 27Al was measured as a control target, since there exists data for 27Al with high resolution and low statistical error [3].

  8. Ultrathin TaOx film based photovoltaic device

    International Nuclear Information System (INIS)

    Tyagi, Pawan

    2011-01-01

    Application of the economical metal oxide thin-film photovoltaic devices is hindered by the poor energy efficiency. This paper investigates the photovoltaic effect with an ultrathin tantalum oxide (TaOx) tunnel barrier, formed by the plasma oxidation of a pre-deposited tantalum (Ta) film. These ∼ 3 nm TaOx tunnel barriers showed approximately 160 mV open circuit voltage and 3-5% energy efficiency, for varying light intensity. The ultrathin TaOx (∼ 3 nm) could absorb approximately 12% of the incident light radiation in 400-1000 nm wavelength range; this strong light absorbing capability was found to be associated with the dramatically large extinction coefficient. Spectroscopic ellipsometry revealed that the extinction coefficient of 3 nm TaOx was ∼ 0.2, two orders higher than that of tantalum penta oxide (Ta 2 O 5 ). Interestingly, refractive index of this 3 nm thick TaOx was comparable with that of stochiometeric Ta 2 O 5 . However, heating and prolonged high-intensity light exposure deteriorated the photovoltaic effect in TaOx junctions. This study provides the basis to explore the photovoltaic effect in a highly economical and easily processable ultrathin metal oxide tunnel barrier or analogous systems.

  9. Preparation of Ta Te2 thin films by laser ablation

    International Nuclear Information System (INIS)

    Zidan, M.D.; Alkhwam, M.; Alkhasm, M.

    2006-03-01

    The laser ablation system consisting of a vacuum chamber and Nd-YAG laser has been built for deposition TaTe 2 on three different substrates (Silicon, glass, and Aluminium). The surface topography of the prepared thin films has been studied by atomic force microscopy (AFM). TaTe 2 powder was characterized by using x-ray diffraction. The crystallinity of the thin films was examined by x-ray diffraction (XRD). The results show no peaks corresponding TaTe 2 , but there are some indications to the Ta 3 N 5 . (author)

  10. Thermodynamic description of the Ta-W-Zr system

    International Nuclear Information System (INIS)

    Guo, Cuiping; Li, Changrong; Du, Zhenmin; Shang, Shunli

    2014-01-01

    The Ta-W, W-Zr and Ta-W-Zr systems are critically reviewed and modeled using the CALPHAD technique. The enthalpy of formation of the stoichiometric compound W 2 Zr in the W-Zr system is predicted from first-principles calculations. The solution phases (liquid, bcc and hcp) are modeled by the substitutional solution model. The compound W 2 Zr is treated with the formula (Ta,W) 2 Zr in the Ta-W-Zr system because of a significant solid solubility of Ta in W 2 Zr. All experimental data, including the Gibbs energy of formation, enthalpy of formation, activity of Ta and W of bcc phase at 1 200 K, Ta-W and W-Zr phase diagrams, and three isothermal sections of the Ta-W-Zr system at 1 073, 1 098, and 1 873 K, are reproduced in the present work. A set of self-consistent thermodynamic parameters of the Ta-W-Zr system is obtained.

  11. Deposition and characterization of TaAIN thin films by reactive magnetron sputtering; Deposicao e caracterizacao de filmes finos de TaAIN depositados por magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, G.B.; Fernandez, D.R.; Fontes Junior, A.S.; Felix, L.C.; Tentardini, E.K. [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil). Departamento de Ciencia e Engenharia de Materiais; Hubler, R. [Pontificia Universidade Catolica do Rio Grande do Sul (PUC-RS), RS (Brazil); Silva Junior, A.H. da, E-mail: brito-g@hotmail.com [Universidade Federal do Rio Grande do Sul (UFRGS), RS (Brazil)

    2016-07-01

    Phase stability, oxidation resistance and great mechanical properties are the main objectives when synthesizing protective coatings. The tantalum nitride (TaN) has aroused interest because of its high temperature stability, chemical inertness and thermal conductivity. However, it has a low hardness value when compared to other coatings. Researches has shown that one way to improvements in the properties of a thin film is by adding other elements in the deposition process. Therefore, the objective of this study was to deposit thin films of TaAlN by magnetron sputtering, changing the aluminum concentration of 2, 5, 7, to 14%. Then the coatings were characterized by EDS, RBS, GIXRD and nanohardness. In this study was found that the aluminum deposited did not change the oxidation resistance of the coating, and the highest value of hardness was 28 GPa for the sample with 14 at.%. (author)

  12. Electroexcitation of giant resonances in 181Ta

    International Nuclear Information System (INIS)

    Hicks, R.S.; Auer, I.P.; Bergstrom, J.C.; Caplan, H.S.

    1977-01-01

    The giant resonance region of 181 Ta has been investigated by means of inelastic electron scattering with primary electron energies of 79.1 to 118.3 MeV. A peak-fitting procedure was employed to separate the measured spectrum into nine different resonance components. Multipolarity and strength assignments were deduced using DWBA analysis with the Goldhaber-Teller and Steinwedel-Jensen models. In addition to the well-known giant dipole structure, other resonances were identified at 23.2+-0.3 MeV (E2), 9.5+-0.2 and 11.5+-0.2 MeV (E2 or E0), 19.5+-0.8 MeV (E3), 3.70+-0.14 MeV (E3 or E4), and 5.40+-0.15 MeV (E4 or E5). The model dependence of the analysis is discussed. (Auth.)

  13. The Mo/Ta (100) interface

    International Nuclear Information System (INIS)

    Quintanar, C.; Velasco, V.R.; Garcia-Moliner, F.

    1990-12-01

    We have calculated the interface local density of states (ILDOS) formed by the transition metals Mo/Ta using a tight-binding Slater-Koster description and the Green Function matching method together with quickly converging algorithms to compute the transfer matrices. We obtain the surface LDOS as a byproduct. Our result is a useful tool to analyze experimental results and to check models as a function of the value of the tight-binding parameters either of the bulk or at the interface itself. We consider the (100) direction. We compare the interface to the bulk and to the surface and comment on some recently found experimental results for this interface. (author). 17 refs, 2 figs

  14. LRAD surface monitoring results at TA-21

    International Nuclear Information System (INIS)

    Bounds, J.A.

    1995-01-01

    In August/September 1994, NIS-6 personnel used LRAD soil surface monitor technology to characterize the extent of alpha contamination on the surface of a parking lot adjacent to TA-21, LANL, known as Material Disposal Area B. This report documents that monitoring. Based on this survey, there is no reason for concern about significant contamination in the parking area as a whole, although unexpected small hot spots could exist between the grid points where monitoring was performed. However, the grouping of high readings on the east side of the parking area does point to possible contamination at the level of 100 dpm/100 cm 2 or less (above background). Further monitoring or remediation of this area seems appropriate. In addition, because this was an alpha survey, one cannot rule out contamination under the asphalt or possibly between layers if it was paved more than once

  15. 40 CFR 91.421 - Dilute gaseous exhaust sampling and analytical system description.

    Science.gov (United States)

    2010-07-01

    ... Pump—Constant Volume Sampler (PDP-CVS) system with a heat exchanger, or a Critical Flow Venturi... gas mixture temperature, measured at a point immediately ahead of the critical flow venturi, must be.... (a) General. The exhaust gas sampling system described in this section is designed to measure the...

  16. Development of Ta3N5 as an Efficient Visible Light-responsive Photocatalyst for Water Oxidation

    KAUST Repository

    Nurlaela, Ela

    2015-09-01

    Along with many other solar energy conversion processes, research on photocatalytic water splitting to generate hydrogen and oxygen has experienced rapid major development over the past years. Developing an efficient visible-light-responsive photocatalyst has been one of the targets of such research efforts. In this regard, nitride materials, particularly Ta3N5, have been the subject of investigation due to their promising properties. This dissertation focuses on the fundamental parameters involved in the photocatalytic processes targeting overall water splitting using Ta3N5 as a model photocatalyst. The discussion primarily focuses on relevant parameters that are involved in photon absorption, exciton separation, carrier diffusion, carrier transport, and catalytic efficiency. A collection of theoretical and experimental studies of properties associated with Ta3N5 have been utilized to obtain a comprehensive understanding of this material. The fundamental structural and optoelectronic properties of Ta3N5 have been addressed. From the electronic properties, the dielectric constant and effective masses have been calculated. Because of its high dielectric constant and relatively low effective masses, Ta3N5 is promising for photocatalytic reaction applications. Studies of lattice dynamics, optical properties, and band positions have been able to clearly show that the synthesized Ta3N5 is essentially non-stoichiometric and that a truly pure phase of Ta3N5 has never been achieved, even though XRD has shown a pure phase sample. The photophysical properties of Ta3N5, such as the absorption coefficient, carrier mobility, and carrier lifetime, have been experimentally measured by synthesizing Ta3N5 thin films. Very low kinetic properties with very low transport properties and fast carrier recombination explained why overall water splitting has never been achieved with Ta3N5 as a photocatalyst to date. The extent to which the surface states of Ta3N5 photocatalysts affect

  17. Phonon and thermal properties of exfoliated TaSe{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Z.; Jiang, C.; Renteria, J. [Nano-Device Laboratory, Department of Electrical Engineering, Bourns College of Engineering, University of California–Riverside, Riverside, California 92521 (United States); Pope, T. R.; Tsang, C. F.; Stickney, J. L.; Salguero, T. T., E-mail: salguero@uga.edu, E-mail: balandin@ee.ucr.edu [Department of Chemistry, University of Georgia, Athens, Georgia 30602 (United States); Goli, P. [Materials Science and Engineering Program, Bourns College of Engineering, University of California–Riverside, Riverside, California 92521 (United States); Balandin, A. A., E-mail: salguero@uga.edu, E-mail: balandin@ee.ucr.edu [Nano-Device Laboratory, Department of Electrical Engineering, Bourns College of Engineering, University of California–Riverside, Riverside, California 92521 (United States); Materials Science and Engineering Program, Bourns College of Engineering, University of California–Riverside, Riverside, California 92521 (United States)

    2013-11-28

    We report on the phonon and thermal properties of thin films of tantalum diselenide (2H-TaSe{sub 2}) obtained via the “graphene-like” mechanical exfoliation of crystals grown by chemical vapor transport. The ratio of the intensities of the Raman peak from the Si substrate and the E{sub 2g} peak of TaSe{sub 2} presents a convenient metric for quantifying film thickness. The temperature coefficients for two main Raman peaks, A{sub 1g} and E{sub 2g}, are −0.013 and −0.0097 cm{sup −1}/{sup o}C, respectively. The Raman optothermal measurements indicate that the room temperature thermal conductivity in these films decreases from its bulk value of ∼16 W/mK to ∼9 W/mK in 45-nm thick films. The measurement of electrical resistivity of the field-effect devices with TaSe{sub 2} channels shows that heat conduction is dominated by acoustic phonons in these van der Waals films. The scaling of thermal conductivity with the film thickness suggests that the phonon scattering from the film boundaries is substantial despite the sharp interfaces of the mechanically cleaved samples. These results are important for understanding the thermal properties of thin films exfoliated from TaSe{sub 2} and other metal dichalcogenides, as well as for evaluating self-heating effects in devices made from such materials.

  18. Phonon and thermal properties of exfoliated TaSe2 thin films

    International Nuclear Information System (INIS)

    Yan, Z.; Jiang, C.; Renteria, J.; Pope, T. R.; Tsang, C. F.; Stickney, J. L.; Salguero, T. T.; Goli, P.; Balandin, A. A.

    2013-01-01

    We report on the phonon and thermal properties of thin films of tantalum diselenide (2H-TaSe 2 ) obtained via the “graphene-like” mechanical exfoliation of crystals grown by chemical vapor transport. The ratio of the intensities of the Raman peak from the Si substrate and the E 2g peak of TaSe 2 presents a convenient metric for quantifying film thickness. The temperature coefficients for two main Raman peaks, A 1g and E 2g , are −0.013 and −0.0097 cm −1 / o C, respectively. The Raman optothermal measurements indicate that the room temperature thermal conductivity in these films decreases from its bulk value of ∼16 W/mK to ∼9 W/mK in 45-nm thick films. The measurement of electrical resistivity of the field-effect devices with TaSe 2 channels shows that heat conduction is dominated by acoustic phonons in these van der Waals films. The scaling of thermal conductivity with the film thickness suggests that the phonon scattering from the film boundaries is substantial despite the sharp interfaces of the mechanically cleaved samples. These results are important for understanding the thermal properties of thin films exfoliated from TaSe 2 and other metal dichalcogenides, as well as for evaluating self-heating effects in devices made from such materials

  19. Phonon and thermal properties of exfoliated TaSe2 thin films

    Science.gov (United States)

    Yan, Z.; Jiang, C.; Pope, T. R.; Tsang, C. F.; Stickney, J. L.; Goli, P.; Renteria, J.; Salguero, T. T.; Balandin, A. A.

    2013-11-01

    We report on the phonon and thermal properties of thin films of tantalum diselenide (2H-TaSe2) obtained via the "graphene-like" mechanical exfoliation of crystals grown by chemical vapor transport. The ratio of the intensities of the Raman peak from the Si substrate and the E2g peak of TaSe2 presents a convenient metric for quantifying film thickness. The temperature coefficients for two main Raman peaks, A1g and E2g, are -0.013 and -0.0097 cm-1/oC, respectively. The Raman optothermal measurements indicate that the room temperature thermal conductivity in these films decreases from its bulk value of ˜16 W/mK to ˜9 W/mK in 45-nm thick films. The measurement of electrical resistivity of the field-effect devices with TaSe2 channels shows that heat conduction is dominated by acoustic phonons in these van der Waals films. The scaling of thermal conductivity with the film thickness suggests that the phonon scattering from the film boundaries is substantial despite the sharp interfaces of the mechanically cleaved samples. These results are important for understanding the thermal properties of thin films exfoliated from TaSe2 and other metal dichalcogenides, as well as for evaluating self-heating effects in devices made from such materials.

  20. Artificially controlled stress anisotropy and magnetic properties of FeTaN thin films

    International Nuclear Information System (INIS)

    Deng, H.; Jarratt, J.D.; Minor, M.K.; Barnard, J.A.

    1997-01-01

    This article presents a new method of investigating internal stress effects on thin film magnetic properties, in this case magnetically soft FeTaN sputtered films. The FeTaN films were deposited on a series of oxidized silicon (111) substrates prestressed to different degrees. During sputtering all the deposition conditions were kept exactly the same for all the samples. However, anisotropic stresses with different amplitudes are systematically introduced into the films when the prestressed wafers were released. In this way, FeTaN films with compressive stress varying from 80 to 608 MPa are produced. We found that the saturation magnetostriction (λ s ), anisotropy field (H k ), initial permeability (μ i ) as well as easy axis orientation of FeTaN thin films are strongly affected by the induced stress anisotropy. A stress ratio concept is proposed as a measure of the degree of the stress anisotropy. Models for easy-hard axis switching induced by stress for magnetic films with positive magnetostriction are discussed. copyright 1997 American Institute of Physics

  1. Correlation between hardness and stress in Al-(Nb, Mo, Ta) thin films

    Energy Technology Data Exchange (ETDEWEB)

    Car, T., E-mail: car@irb.h [Rudjer Boskovic Institute, Division of Materials Science, Bijenicka cesta 54, 10000 Zagreb, P.O.B. 1016 (Croatia); Radic, N. [Rudjer Boskovic Institute, Division of Materials Science, Bijenicka cesta 54, 10000 Zagreb, P.O.B. 1016 (Croatia); Panjan, P.; Cekada, M. [Jozef Stefan Institute, Ljubljana (Slovenia); Tonejc, A. [Department of Physics, Bijenicka cesta 32, 10000 Zagreb, P.O.B. 331 (Croatia)

    2009-06-30

    The thin films of Al{sub x}Nb{sub 1-x} (95 {>=} x {>=} 20), Al{sub x}Mo{sub x} (90 {>=} x {>=} 20) and Al{sub x}Ta{sub 1-x} (95 {>=} x {>=} 20) were prepared by magnetron codeposition at room temperature. The average film thickness was from 325 to 400 nm, depending on the film composition. The structure of the as-deposited films was examined by the X-ray diffraction. The stress of the films was determined from the substrate deformation by the profilometer, and the microhardness (load 2 mN) was examined by the micro- and nano-hardness device. For the purpose of the examination of the hardness, the samples were deposited onto the sapphire wafers, while the examination of the film stress, was performed by using thin glass substrates. For all the Al-(Nb, Mo, Ta) alloy compositions, the microhardness is predominantly under the influence of the harder element, and monotonically decreases with the increase of the aluminum content. However, the microhardness of the amorphous AlTa films was higher than the bulk value of a harder element (Ta) in the alloy. A simple empirical linear relationship between the Vickers hardness, the bulk value hardness of the transition metal (harder element) and the elastic energy fraction of the identation deformation, was established. The elastic energy fraction in the microhardness is also linearly correlated with the stress in films.

  2. The TaSST: Tactile Sleeve for Social Touch

    NARCIS (Netherlands)

    Huisman, G.; Darriba Frederiks, A.; van Dijk, B.; Heylen, D.; Kröse, B.

    2013-01-01

    In this paper we outline the design process of the TaSST (Tactile Sleeve for Social Touch), a touch-sensitive vibrotactile arm sleeve. The TaSST was designed to enable two people to communicate different types of touch over a distance. The touch-sensitive surface of the sleeve consists of a grid of

  3. The TaSST: Tactile sleeve for social touch

    NARCIS (Netherlands)

    Huisman, Gijs; Darriba Frederiks, Aduén; van Dijk, Elisabeth M.A.G.; Heylen, Dirk K.J.; Krose, Ben

    In this paper we outline the design process of the TaSST (Tactile Sleeve for Social Touch), a touch-sensitive vibrotactile arm sleeve. The TaSST was designed to enable two people to communicate different types of touch over a distance. The touch-sensitive surface of the sleeve consists of a grid of

  4. The TaSST - Tactile Sleeve for Social Touch

    NARCIS (Netherlands)

    Huisman, Gijs; Darriba Frederiks, Aduén; Van Dijk, Betsy; Heylen, Dirk

    2013-01-01

    In this paper we outline the design process of TaSST (Tactile Sleeve for Social Touch), a touch-sensitive vibrotactile arm sleeve. The TaSST was designed to enable two people to communicate different types of touches over a distance. The touch-sensitive surface of the sleeve consists of a grid of

  5. 76 FR 50739 - Hung Ta Fan: Debarment Order

    Science.gov (United States)

    2011-08-16

    ...] Hung Ta Fan: Debarment Order AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The... (the FD&C Act) debarring Hung Ta Fan for a period of 5 years from importing articles of food or.... Fan was convicted of a felony under Federal law for conduct relating to the importation into the...

  6. An update on the thermodynamics of Ta2O5

    International Nuclear Information System (INIS)

    Jacob, K.T.; Shekhar, Chander; Waseda, Y.

    2009-01-01

    Using a solid-state electrochemical cell incorporating yttria-doped thoria (YDT) as the electrolyte and a mixture of (Mn + MnO) as the reference electrode, standard Gibbs free energy of formation of β-Ta 2 O 5 has been determined as a function of temperature in the range (1000 to 1300) K. The solid-state electrochemical cell used can be represented as (-)Pt,Ta+Ta 2 O 5 //(Y 2 O 3 )ThO 2 //Mn+MnO,Pt(+) Combining the reversible e.m.f. of the cell with recent data on the free energy of formation of MnO, standard Gibbs free energy of formation of Ta 2 O 5 from Ta metal and diatomic oxygen gas (O 2 ) in the temperature range (1000 to 1300) K is obtained: Δ f G 0 ±0.35/(kJ.mol -1 )=-2004.376+0.40445(T/K). Because of the significant solid solubility of oxygen in tantalum, a small correction for the activity of Ta in the metal phase in equilibrium with Ta 2 O 5 is applied. An analysis of the results obtained in this study and other free energy data reported in the literature by the 'third law' method suggests the need for refining data for Ta 2 O 5 reported in thermodynamic compilations. Used in the analysis is a revised value for standard entropy of Ta 2 O 5 based on more recent low-temperature heat capacity measurements. An improved set of thermodynamic properties of ditantalum pentoxide (Ta 2 O 5 ) are presented in the temperature range (298.15 to 2200) K.

  7. 77 FR 64827 - Investigation Nos. 701-TA-402 and 731-TA-892 (Second Review); Honey From Argentina; Termination...

    Science.gov (United States)

    2012-10-23

    ... INTERNATIONAL TRADE COMMISSION Investigation Nos. 701-TA-402 and 731-TA-892 (Second Review); Honey... revocation of the countervailing duty order and antidumping duty order on imports of honey from Argentina would be likely to lead to continuation or recurrence of material injury. On September 21, 2012, the...

  8. High-pressure phases of Weyl semimetals NbP, NbAs, TaP, and TaAs

    Science.gov (United States)

    Guo, ZhaoPeng; Lu, PengChao; Chen, Tong; Wu, JueFei; Sun, Jian; Xing, DingYu

    2018-03-01

    In this study, we used the crystal structure search method and first-principles calculations to systematically explore the highpressure phase diagrams of the TaAs family (NbP, NbAs, TaP, and TaAs). Our calculation results show that NbAs and TaAs have similar phase diagrams, the same structural phase transition sequence I41 md→ P6¯ m2→ P21/ c→ Pm3¯ m, and slightly different transition pressures. The phase transition sequence of NbP and TaP differs somewhat from that of NbAs and TaAs, in which new structures emerge, such as the Cmcm structure in NbP and the Pmmn structure in TaP. Interestingly, we found that in the electronic structure of the high-pressure phase P6¯ m2-NbAs, there are coexistingWeyl points and triple degenerate points, similar to those found in high-pressure P6¯ m2-TaAs.

  9. Micro-electrochemical characterization of galvanic corrosion of TA2/316L composite plate

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, X.; Li, X.; Dong, C.; Xiao, K. [Corrosion and Protection Center, University of Science and Technology Beijing (China)

    2011-12-15

    Galvanic corrosion behavior of TA2/316L composite plate was investigated in the solution of 3.5 wt% NaCl by galvanic potential monitoring, scanning localized electrochemical impedance spectroscopy (LEIS) and scanning vibrating micro-electrode (SVME) techniques. The results demonstrated that the pitting corrosion resistance of 316L for the galvanic combination sample is lower, and the coupled current density is higher than for the single 316L sample. It indicates that the galvanic action works on the corrosion behavior of the TA2 titanium alloy/316L stainless steel galvanic combination in sodium chloride solution. The galvanic effect width was determined as 1500 {mu}m. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Improvement of the Reaction Rates of Mg with H{sub 2} by the Addition of TaF{sub 5} via Reactive Mechanical Grinding

    Energy Technology Data Exchange (ETDEWEB)

    Song, Myoung Youp [Chonbuk National University, Jeonju (Korea, Republic of); Kwak, Young Jun; Lee, Seong Ho [Chonbuk National University, Jeonju (Korea, Republic of); Park, Hye Ryoung [Chonnam National University, Gwangju (Korea, Republic of)

    2014-02-15

    A sample with a composition of 90 wt% Mg-10 wt% TaF{sub 5} (named Mg-10TaF{sub 5}) was prepared by reactive mechanical grinding, and its hydriding and dehydriding properties were examined. The activation of Mg-10TaF{sub 5} was not required. At n=1, the sample absorbed 3.63 wt% H for 5 min, 4.03 wt% H for 10 min, and 4.53 wt% H for 30 min at 593 K under 12 bar H2. At n=1, the sample desorbed 0.59 wt% H for 5 min, 1.46 wt% H for 10 min, 3.42 wt% H for 30 min, and 4.24 wt% H for 60 min at 593 K under 1.0 bar H2. Mg-10TaF{sub 5} after reactive mechanical grinding contained MgH{sub 2}, Mg, and very small amounts of MgF{sub 2} and Ta{sub 2}H. The XRD pattern of Mg-10TaF{sub 5} dehydrided at n=3 revealed Mg, MgH{sub 2}, a small amount of MgO, and very small amounts of MgF{sub 2} and Ta{sub 2}H phases. Mg-10Fe{sub 2}O{sub 3} and Mg-10MnO were reported to have quite high hydriding rate and dehydriding rates, respectively. Mg-10TaF{sub 5} had a larger initial hydriding rate but a lower quantity of hydrogen absorbed for 60 min than Mg-10Fe{sub 2}O{sub 3}. However, Mg-10TaF{sub 5} had a higher initial dehydriding rate (after the incubation period) and a larger quantity of hydrogen desorbed for 60 min than Mg-10MnO.

  11. Bioactivity response of Ta_1_-_xO_x coatings deposited by reactive DC magnetron sputtering

    International Nuclear Information System (INIS)

    Almeida Alves, C.F.; Cavaleiro, A.; Carvalho, S.

    2016-01-01

    The use of dental implants is sometimes accompanied by failure due to periimplantitis disease and subsequently poor esthetics when soft–hard tissue margin recedes. As a consequence, further research is needed for developing new bioactive surfaces able to enhance the osseous growth. Tantalum (Ta) is a promising material for dental implants since, comparing with titanium (Ti), it is bioactive and has an interesting chemistry which promotes the osseointegration. Another promising approach for implantology is the development of implants with oxidized surfaces since bone progenitor cells interact with the oxide layer forming a diffusion zone due to its ability to bind with calcium which promotes a stronger bond. In the present report Ta-based coatings were deposited by reactive DC magnetron sputtering onto Ti CP substrates in an Ar + O_2 atmosphere. In order to assess the osteoconductive response of the studied materials, contact angle and in vitro tests of the samples immersed in Simulated Body Fluid (SBF) were performed. Structural results showed that oxide phases where achieved with larger amounts of oxygen (70 at.% O). More compact and smooth coatings were deposited by increasing the oxygen content. The as-deposited Ta coating presented the most hydrophobic character (100°); with increasing oxygen amount contact angles progressively diminished, down to the lowest measured value, 63°. The higher wettability is also accompanied by an increase on the surface energy. Bioactivity tests demonstrated that highest O-content coating, in good agreement with wettability and surface energy values, showed an increased affinity for apatite adhesion, with higher Ca/P ratio formation, when compared to the bare Ti substrates. - Highlights: • Ta_1_-_xO_x coatings were deposited by reactive DC magnetron sputtering. • Amorphous oxide phases were achieved with higher oxygen amounts. • Contact angles progressively diminished, with increasing oxygen content. • Ta oxide surface

  12. Magnetostatics and dynamics of ion irradiatied NiFe/Ta multilayer films studied by vector network analyzer ferromagnetic resonance

    International Nuclear Information System (INIS)

    Marko, Daniel

    2010-01-01

    In the present work, the implications of ion irradiation on the magnetostatic and dynamic properties of soft magnetic Py/Ta (Py=Permalloy: Ni 80 Fe 20 ) single and multilayer films have been investigated with the main objective of finding a way to determine their saturation magnetization. Both polar magneto-optical Kerr effect (MOKE) and vector network analyzer ferromagnetic resonance (VNA-FMR) measurements have proven to be suitable methods to determine μ 0 M S , circumventing the problem of the unknown effective magnetic volume that causes conventional techniques such as SQUID or VSM to fail. Provided there is no perpendicular anisotropy contribution in the samples, the saturation magnetization can be determined even in the case of strong interfacial mixing due to an inherently high number of Py/Ta interfaces and/or ion irradiation with high fluences. Another integral part of this work has been to construct a VNA-FMR spectrometer capable of performing both azimuthal and polar angle-dependent measurements using a magnet strong enough to saturate samples containing iron. Starting from scratch, this comprised numerous steps such as developing a suitable coplanar waveguide design, and writing the control, evaluation, and fitting software. With both increasing ion fluence and number of Py/Ta interfaces, a decrease of saturation magnetization has been observed. In the case of the 10 x Py samples, an immediate decrease of μ 0 M S already sets in at small ion fluences. However, for the 1 x Py and 5 x Py samples, the saturation magnetization remains constant up to a certain ion fluence, but then starts to rapidly decrease. Ne ion irradiation causes a mixing and broadening of the interfaces. Thus, the Py/Ta stacks undergo a transition from being polycrystalline to amorphous at a critical fluence depending on the number of interfaces. The saturation magnetization is found to vanish at a Ta concentration of about 10-15 at.% in the Py layers. The samples possess a small

  13. Magnetostatics and dynamics of ion irradiatied NiFe/Ta multilayer films studied by vector network analyzer ferromagnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Marko, Daniel

    2010-11-25

    In the present work, the implications of ion irradiation on the magnetostatic and dynamic properties of soft magnetic Py/Ta (Py=Permalloy: Ni{sub 80}Fe{sub 20}) single and multilayer films have been investigated with the main objective of finding a way to determine their saturation magnetization. Both polar magneto-optical Kerr effect (MOKE) and vector network analyzer ferromagnetic resonance (VNA-FMR) measurements have proven to be suitable methods to determine {mu}{sub 0}M{sub S}, circumventing the problem of the unknown effective magnetic volume that causes conventional techniques such as SQUID or VSM to fail. Provided there is no perpendicular anisotropy contribution in the samples, the saturation magnetization can be determined even in the case of strong interfacial mixing due to an inherently high number of Py/Ta interfaces and/or ion irradiation with high fluences. Another integral part of this work has been to construct a VNA-FMR spectrometer capable of performing both azimuthal and polar angle-dependent measurements using a magnet strong enough to saturate samples containing iron. Starting from scratch, this comprised numerous steps such as developing a suitable coplanar waveguide design, and writing the control, evaluation, and fitting software. With both increasing ion fluence and number of Py/Ta interfaces, a decrease of saturation magnetization has been observed. In the case of the 10 x Py samples, an immediate decrease of {mu}{sub 0}M{sub S} already sets in at small ion fluences. However, for the 1 x Py and 5 x Py samples, the saturation magnetization remains constant up to a certain ion fluence, but then starts to rapidly decrease. Ne ion irradiation causes a mixing and broadening of the interfaces. Thus, the Py/Ta stacks undergo a transition from being polycrystalline to amorphous at a critical fluence depending on the number of interfaces. The saturation magnetization is found to vanish at a Ta concentration of about 10-15 at.% in the Py layers

  14. Structural and electrical characterization of BiFeO3-NaTaO3 multiferroic

    International Nuclear Information System (INIS)

    Mohanty, Suchismita; Choudhary, R.N.P.; Parida, B.N.; Padhee, R.

    2014-01-01

    Using a standard high-temperature solid-state reaction technique, polycrystalline samples of (Bi 1-x , Na x ) (Fe 1-x , Ta x ) O 3 (x = 0.0, 0.5) were prepared. The formation of the desired materials was confirmed by X-ray diffraction. The surface texture of the prepared materials recorded by scanning electron microscope exhibits a uniform grain distribution with small voids suggesting the formation of high-density pellet samples. The impedance and dielectric properties of the materials were investigated as a function of temperature and frequency. The relative dielectric constant and loss tangent of BiFeO 3 decrease on addition of NaTaO 3 (x = 0.5). The effect of addition of NaTaO 3 on grain and grain boundary contributions in the resistive and capacitive components of BiFeO 3 was studied using complex impedance spectroscopy. The value of activation energy due to both grain and grain boundary of both the samples is nearly same. The nature of variation of dc conductivity confirms the Arrhenius behavior of the materials. Study of frequency dependence of ac conductivity suggests that the materials obey Jonscher's universal power law and the presence of ionic conductivity. (orig.)

  15. Superconductor-Metal-Insulator transition in two dimensional Ta thin Films

    Science.gov (United States)

    Park, Sun-Gyu; Kim, Eunseong

    2013-03-01

    Superconductor-insulator transition has been induced by tuning film thickness or magnetic field. Recent electrical transport measurements of MoGe, Bi, Ta thin films revealed an interesting intermediate metallic phase which intervened superconducting and insulating phases at certain range of magnetic field. Especially, Ta thin films show the characteristic IV behavior at each phase and the disorder tuned intermediate metallic phase [Y. Li, C. L. Vicente, and J. Yoon, Physical Review B 81, 020505 (2010)]. This unexpected metallic phase can be interpreted as a consequence of vortex motion or contribution of fermionic quasiparticles. In this presentation, we report the scaling behavior during the transitions in Ta thin film as well as the transport measurements in various phases. Critical exponents v and z are obtained in samples with wide ranges of disorder. These results reveal new universality class appears when disorder exceeds a critical value. Dynamical exponent z of Superconducting sample is found to be 1, which is consistent with theoretical prediction of unity. z in a metallic sample is suddenly increased to be approximately 2.5. This critical exponent is much larger than the value found in other system and theoretical prediction. We gratefully acknowledge the financial support by the National Research Foundation of Korea through the Creative Research Initiatives.

  16. Magnetism of Ta dichalcogenide monolayers tuned by strain and hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Manchanda, Priyanka; Sellmyer, D. J.; Skomski, Ralph [Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588 (United States); Sharma, Vinit [Department of Materials Science and Engineering and Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Yu, Hongbin [School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States)

    2015-07-20

    The effects of strain and hydrogenation on the electronic, magnetic, and optical properties of monolayers of Ta based dichalcogenides (TaX{sub 2}; X = S, Se, and Te) are investigated using density-functional theory. We predict a complex scenario of strain-dependent magnetic phase transitions involving paramagnetic, ferromagnetic, and modulated antiferromagnetic states. Covering one of the two chalcogenide surfaces with hydrogen switches the antiferromagnetic/nonmagnetic TaX{sub 2} monolayers to a semiconductor, and the optical behavior strongly depends on strain and hydrogenation. Our research opens pathways towards the manipulation of magnetic as well as optical properties for future spintronics and optoelectronics applications.

  17. Studies on Ta-Ni alloys as high-temperature braze for SiC-SiC joined products; Untersuchungen zu Ta-Ni-Legierungen als Hochtemperaturlot fuer SiC-SiC Verbunde

    Energy Technology Data Exchange (ETDEWEB)

    Triebert, Anke; Matthey, Bjoern; Martin, Hans-Peter [Fraunhofer Institut fuer Keramische Technologien und Systeme (IKTS), Dresden (Germany)

    2011-07-01

    Active metal brazes have been already established for a number of decades. The current progress of processing technologies and engineering require new and powerful materials also for high-temperature applications. Up to now there are little technically and industrially applicable brazing materials for operation temperatures above 800 C. The investigations described in this paper concerning the Ta-Ni system intend to be the start of a braze material development, which delivers ceramic-ceramic or ceramic-metal joined products. Besides principal considerations and experiments with regard to the investigated material system of Ta-Ni active metal brazing tests to join SIC-SIC components are presented. The joined ceramic component samples are characterized focusing on their materials structure within the joining zone, their crystalline phases of the braze and their mechanical strength at room temperature and high temperatures. The achieved properties demonstrate that Ta-Ni brazes have the potential for future high temperature brazes for ceramics materials. (orig.)

  18. Resonance spin memory in low-energy gamma-ray spectra from Sb, Tb, Ho and Ta odd-odd compound nuclei

    International Nuclear Information System (INIS)

    Olejniczak, U.; Gundorin, N.A.; Pikelner, L.B.; Serov, D.G.; Przytula, M.

    2002-01-01

    The low-energy gamma-ray spectra from neutron resonance capture with natural samples of Sb, Tb, Ho and Ta were measured using a HPGe detector at the IBR-30 pulsed reactor (JINR, Dubna). The resonance spin memory effect in the spectra from the odd-odd compound nuclei of 122 Sb, 160 Tb and 166 Ho was found to be quite distinct. For the 182 Ta compound nucleus it proved to be rather weak

  19. Photocatalytic and photoelectrochemical performance of Ta{sub 3}N{sub 5} microcolumn films fabricated using facile reactive sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Der-Hwa [Department of Materials Science and Engineering, National Cheng Kung University, No. 1 University Road, Tainan City 70101, Taiwan (China); Chang, Kao-Shuo, E-mail: kschang@mail.ncku.edu.tw [Department of Materials Science and Engineering, National Cheng Kung University, No. 1 University Road, Tainan City 70101, Taiwan (China); Promotion Center for Global Materials Research, National Cheng Kung University, No. 1 University Road, Tainan City 70101, Taiwan (China)

    2016-08-21

    This paper presents the photocatalytic and photoelectrochemical (PEC) properties of Ta{sub 3}N{sub 5} microcolumn films. The highlights include (1) overcoming the fundamental barrier of standard reactive sputtering for fabricating microcolumns; (2) preventing unnecessary complexity from complicating facile sputtering; (3) an alternative but effective approach for fabricating Ta{sub 3}N{sub 5} without using caustic NH{sub 3} gases; (4) investigating morphology tuning for favorable photocatalysis and PEC reactions; and (5) elucidating the relationships of the structures, morphologies, and properties of Ta{sub 3}N{sub 5} microcolumns. High-resolution transmission electron microscopy and selective-area electron diffraction verified the polycrystallinity of Ta{sub 3}N{sub 5} microcolumns, of which the elemental compositions and stoichiometry were measured using electron-probe energy dispersive spectroscopy, Auger electron spectroscopy, and X-ray photoelectron spectroscopy. The corresponding band gap was determined to be approximately 2.1 eV. The sample exhibited a superior photodegradation capability; the photodegradation rate constant k was determined to be approximately 1.4 times higher than that of P25 under UV irradiation. A photocatalytic and PEC cycling test indicated the photodegradation reusability and photostability of the Ta{sub 3}N{sub 5} microcolumns. The incident photon-to-current efficiency performance reached 6%, suggesting that these microcolumns hold potential for application in PEC devices.

  20. Relaxations in Ba{sub 2}BiTaO{sub 6} ceramics investigated by impedance and electric modulus spectroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Joao Elias Figuereido Soares [Departamento de Fisica - CCET, Universidade Federal do Maranhao, Campus do Bacanga, 65085-580, Sao Luis -MA (Brazil); Paschoal, Carlos William de Araujo, E-mail: paschoal@ufma.br [Departamento de Fisica - CCET, Universidade Federal do Maranhao, Campus do Bacanga, 65085-580, Sao Luis -MA (Brazil); Silva, Eder Nascimento [Departamento de Fisica - CCET, Universidade Federal do Maranhao, Campus do Bacanga, 65085-580, Sao Luis -MA (Brazil); Mince, Kathryn A.; Lufaso, Michael W. [Department of Chemistry, University of North Florida, 1 UNF Drive, Jacksonville, FL 32224 (United States)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer We have confirmed that the relaxation observed in Ba{sub 2}BiTaO{sub 6} is due to the conduction mechanism. Black-Right-Pointing-Pointer The conduction mechanism is the oxygen vacancies hopping. Black-Right-Pointing-Pointer We have explained because the activation energy for the Ba{sub 2}BiTaO{sub 6} is lower than observed for Ba{sub 2}BiSbO{sub 6} with basis in zero-point energy of both materials. Black-Right-Pointing-Pointer We have showed that a minor secondary phase is a minor secondary phase, which is common when the BBTO is obtained by ceramic method under air, does not change significantly the electrical properties of BBTO. -- Abstract: Impedance spectroscopy analysis of the dielectric properties of a Ba{sub 2}BiTaO{sub 6} ceramic was performed in the temperature range from room temperature to 500 K. The sample was prepared using conventional solid state synthesis under air and the X-ray diffraction shows the presence of Ba{sub 5}Ta{sub 4}O{sub 15} as a minor secondary phase (0.09%). The impedance data clearly show contributions of the grain and grain boundary. The results indicate that the conduction in Ba{sub 2}BiTaO{sub 6} is due to hopping of oxygen vacancies and that the impurities not influence the conduction mechanism.

  1. Variable substrate temperature deposition of CoFeB film on Ta for manipulating the perpendicular coercive forces

    Science.gov (United States)

    Lakshmanan, Saravanan; Rao, Subha Krishna; Muthuvel, Manivel Raja; Chandrasekaran, Gopalakrishnan; Therese, Helen Annal

    2017-08-01

    Magnetization of Ta/CoFeB/Ta trilayer films with thick layer of CoFeB deposited under different substrate temperatures (Ts) via ultra-high vacuum DC sputtering technique has been measured with the applied magnetic field parallel and perpendicular to the plane of the film respectively to study the perpendicular coercive forces of the film. The samples were further analyzed for its structural, topological, morphological, and electrical transport properties. The core chemical states for the elements present in the CoFeB thin film were analyzed by XPS studies. Magnetization studies reveal the existence of perpendicular coercive forces in CoFeB films deposited only at certain temperatures such as RT, 450 °C, 475 °C and 500 °C. CoFeB film deposited at 475 °C exhibited a maximum coercivity of 315 Oe and a very low saturation magnetization (Ms) of 169 emu/cc in perpendicular direction. This pronounced effect in perpendicular coercive forces observed for CoFeB475 could be attributed to the effect of temperature in enhancing the crystallization of the film at the Ta/CoFeB interfaces. However at temperatures higher than 475 °C the destruction of the Ta/CoFeB interface due to intermixing of Ta and CoFeB results in the disappearance of magnetic anisotropy.

  2. Synthesis and Characterization of K-Ta Mixed Oxides for Hydrogen Generation in Photocatalysis

    Directory of Open Access Journals (Sweden)

    Beata Zielińska

    2012-01-01

    Full Text Available K-Ta mixed oxides photocatalysts have been prepared by impregnation followed by calcination. The influence of the reaction temperature (450°C–900°C on the phase formation, crystal morphology, and photocatalytic activity in hydrogen generation of the produced materials was investigated. The detailed analysis has revealed that all products exhibit high crystallinity and irregular structure. Moreover, two different crystal structures of potassium tantalates such as KTaO3 and K2Ta4O11 were obtained. It was also found that the sample composed of KTaO3 and traces of unreacted Ta2O5 (annealed at 600°C exhibits the highest activity in the reaction of photocatalytic hydrogen generation. The crystallographic phases, optical and vibronic properties were examined by X-ray diffraction (XRD and diffuse reflectance (DR UV-vis and resonance Raman spectroscopic methods, respectively. Morphology and chemical composition of the produced samples were studied using a high-resolution transmission electron microscope (HR-TEM and an energy dispersive X-ray spectrometer (EDX as its mode.

  3. Determination of Ti, Cr, Cu and Ta in niobium oxide by X-ray fluorescence method

    International Nuclear Information System (INIS)

    Dixit, R.M.; Deshpande, S.S.

    1986-01-01

    An x-ray fluorescence method for the determination of Ti, Cr, Cu and Ta in niobium oxide has been developed. Samples/standards in powder form are mixed with boric acid in the proportion of 1:1 (400 mg. each). Double layer pellets are prepared by pressing this mixture over a primary boric acid pellet. Philips PW-1220, a semiautomatic x-ray spectrometer with tungsten target x-ray tube for excitation and LiF (200) crystal for dispersion have been used. The determination range is from 0.005 to 0.1per cent for Ti and Cr, 0.01 to 0.1per cent for Cu and 0.05 to 1per cent for Ta. (author)

  4. Negative magnetoresistance without well-defined chirality in the Weyl semimetal TaP.

    Science.gov (United States)

    Arnold, Frank; Shekhar, Chandra; Wu, Shu-Chun; Sun, Yan; Dos Reis, Ricardo Donizeth; Kumar, Nitesh; Naumann, Marcel; Ajeesh, Mukkattu O; Schmidt, Marcus; Grushin, Adolfo G; Bardarson, Jens H; Baenitz, Michael; Sokolov, Dmitry; Borrmann, Horst; Nicklas, Michael; Felser, Claudia; Hassinger, Elena; Yan, Binghai

    2016-05-17

    Weyl semimetals (WSMs) are topological quantum states wherein the electronic bands disperse linearly around pairs of nodes with fixed chirality, the Weyl points. In WSMs, nonorthogonal electric and magnetic fields induce an exotic phenomenon known as the chiral anomaly, resulting in an unconventional negative longitudinal magnetoresistance, the chiral-magnetic effect. However, it remains an open question to which extent this effect survives when chirality is not well-defined. Here, we establish the detailed Fermi-surface topology of the recently identified WSM TaP via combined angle-resolved quantum-oscillation spectra and band-structure calculations. The Fermi surface forms banana-shaped electron and hole pockets surrounding pairs of Weyl points. Although this means that chirality is ill-defined in TaP, we observe a large negative longitudinal magnetoresistance. We show that the magnetoresistance can be affected by a magnetic field-induced inhomogeneous current distribution inside the sample.

  5. Deposition and characterization of TaAIN thin films by reactive magnetron sputtering

    International Nuclear Information System (INIS)

    Oliveira, G.B.; Fernandez, D.R.; Fontes Junior, A.S.; Felix, L.C.; Tentardini, E.K.; Silva Junior, A.H. da

    2016-01-01

    Phase stability, oxidation resistance and great mechanical properties are the main objectives when synthesizing protective coatings. The tantalum nitride (TaN) has aroused interest because of its high temperature stability, chemical inertness and thermal conductivity. However, it has a low hardness value when compared to other coatings. Researches has shown that one way to improvements in the properties of a thin film is by adding other elements in the deposition process. Therefore, the objective of this study was to deposit thin films of TaAlN by magnetron sputtering, changing the aluminum concentration of 2, 5, 7, to 14%. Then the coatings were characterized by EDS, RBS, GIXRD and nanohardness. In this study was found that the aluminum deposited did not change the oxidation resistance of the coating, and the highest value of hardness was 28 GPa for the sample with 14 at.%. (author)

  6. Closure certification report: TA-35 TSL-125 surface impoundment

    International Nuclear Information System (INIS)

    1991-01-01

    This report summarizes the actions that were taken to clean close the TA-35 TSL-125 surface impoundment Building 125 is used for developing electron guns and related laser assemblies/equipment for a Laser Technology Research Program at the Laboratory. There is no permanent outfall from the surface impoundment; however, the impoundment accidentally overtopped on December 3, 1986, spilling an unknown volume of insulating oil and water into Ten Site Canyon. Sandbags were installed around the surface impoundment on June 25, 1988, to provide additional freeboard in the impoundment and reduce the risk of overtopping during a precipitation event. On July 1, 1988, the impoundment again overtopped releasing an unknown volume of insulating oil and water. Actions taken include removal of waste from the surface impoundment and its associated structures, decontamination of the floor trough and piping inside Building 125, grouting of the piping connecting the floor drain/trough system to the impoundment, decontamination, removal, and disposal of the impoundment liner and sandbags lining the top of the impoundment, and removal and disposal of contaminated soil underlying the impoundment area. Procedures followed to verify that clean closure objectives have been met are also documented in this report. Initial verification was performed through an extensive soil sampling and analysis program

  7. 75 FR 66794 - Notice of Affirmative Determination Regarding Application for Reconsideration: TA-W-71,572...

    Science.gov (United States)

    2010-10-29

    ... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-71,572; TA-W-71,572A; TA-W-71,572B; TA-W-71,572C] Notice of Affirmative Determination Regarding Application for Reconsideration: TA-W...; TA-W-71,572A, Severstal Wheeling, Inc., a Subsidiary of Severstal North America, Inc., Yorkville, OH...

  8. Structure and high photocatalytic activity of (N, Ta)-doped TiO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Le, N. T. H.; Lam, V. D.; Manh, D. H.; Hong, L. V. [Institute of Materials Science, Vietnam Academy of Science and Technology, 18-Hoang Quoc Viet, Hanoi (Viet Nam); Thanh, T. D., E-mail: thanhxraylab@yahoo.com, E-mail: scyu@cbnu.ac.kr [Institute of Materials Science, Vietnam Academy of Science and Technology, 18-Hoang Quoc Viet, Hanoi (Viet Nam); Department of Physics, Chungbuk National University, Cheongju 28644 (Korea, Republic of); Pham, V.-T. [Center for Quantum Electronics, Institute of Physics, Vietnam Academy of Science and Technology, Hanoi (Viet Nam); Synchrotron SOLEIL, L' Orme des Merisiers, Boîte Postale, 48, 91192 Gif-sur-Yvette Cedex (France); Phan, T. L.; Yu, S. C., E-mail: thanhxraylab@yahoo.com, E-mail: scyu@cbnu.ac.kr [Department of Physics, Chungbuk National University, Cheongju 28644 (Korea, Republic of); Anh, T. X. [Center for Quantum Electronics, Institute of Physics, Vietnam Academy of Science and Technology, Hanoi (Viet Nam); Le, T. K. C. [Institut des Sciences Moleculaires d' Orsay, CNRS, Univ Paris-Sud, 91405 Orsay Cedex (France); Thammajak, N. [Synchrotron Light Research Institute, 111 University Avenue, Muang, Nakhon Ratchasima 30000 (Thailand)

    2016-10-14

    A hydrothermal method was used to prepare three nano-crystalline samples of TiO{sub 2} (S1), N-doped TiO{sub 2} (S2), and (N, Ta)-codoped TiO{sub 2} (S3) with average crystallite sizes (D) of 13–25 nm. X-ray diffraction studies confirmed a single phase of the samples with a tetragonal/anatase structure. A slight increase in the lattice parameters was observed when N and/or Ta dopants were doped into the TiO{sub 2} host lattice. Detailed analyses of extended X-ray absorption spectra indicated that N- and/or Ta-doping into TiO{sub 2} nanoparticles influenced the co-ordination number and radial distance (R) of Ti ions in the anatase structure. Concerning their absorption spectra, (N, Ta)-doping narrowed the band gap (E{sub g}) of TiO{sub 2} from 3.03 eV for S1 through 2.94 eV for S2 to 2.85 eV for S3. Such results revealed the applicability of these nanoparticles in the photocatalytic field working in the ultraviolet (UV)-visible region. Among these, photocatalytic activity of S3 was the strongest. By using S3 as a catalyst powder, the degradation efficiency of methylene blue solution was about 99% and 93% after irradiation of UV-visible light for 75 min and visible-light for 180 min, respectively.

  9. Modelling the mechanical behaviour of heterogeneous Ta/TA6V welded joints: behaviour and failure criteria; Modelisation du comportement mecanique des liaisons soudees heterogenes Ta/TA6V: comportement et critere de rupture

    Energy Technology Data Exchange (ETDEWEB)

    Paris, Th

    2008-12-15

    As laser welding of two different materials (heterogeneous welding) leads to a joint having a characteristic size close to the millimetre, i.e. much smaller than that of a structure, and as such a junction displays completely different mechanical properties because of the metallurgical transformations induced by intense thermal loading, the aim of this research thesis is to develop a behaviour model, flexible and robust enough, to represent all together the mechanical behaviours of the Ta, the TA6V and the melted zone. This model must be able to take plasticity and visco-plasticity into account, and also to provide a failure criterion through damage mechanics and its coupling with the behaviour. The author first reports the experimental characterization of the base materials (Ta and TA6V) by using tensile tests under different strain rates and different directions, relaxation tests and fatigue shear tests. He also characterizes the melted zone by describing the influence of a thermal treatment (induced by welding) on the formation of the melted zone, and by using different tests: four point bending on notched specimens, nano-indentation test, and longitudinal tensile test. In a second part, the author develops the model within the framework of continuum thermodynamics, and explores the numerical issues. The last part deals with the validation of the model for the concerned materials (Ta and TA6V) and melted zone.

  10. Photocatalytic hydrogen production using visible-light-responsive Ta 3N5 photocatalyst supported on monodisperse spherical SiO2 particulates

    KAUST Repository

    Liu, Xiaoming

    2014-01-01

    Fine nanoparticles of Ta3N5 (10-20 nm) were synthesized on the surfaces of SiO2 spheres with a diameter of ∼550 nm. A sol-gel method was used to modify the surface of SiO2 with Ta2O5 from TaCl5 dissolved in ethanol in the presence of citric acid and polyethylene glycol. The resulting oxide composites were treated in an NH3 flow at 1123 K to form core-shell structured Ta3N5/SiO2 sub-microspheres. The obtained samples were characterized using powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectra (EDX), transmission electron microscopy (TEM), and photocatalytic activity measurements for H 2 evolution from an aqueous methanol solution. The XRD results demonstrate the expected sequential formation of Ta2O5 layers, followed by Ta3N5 after nitridation on the Ta 2O5/SiO2 composite. SEM and TEM observations indicate that the obtained Ta3N5/SiO2 sub-microspheres have a uniform size distribution with high crystallinity and an obvious core-shell structure. The presence of support maintained the intrinsic photocatalytic activity of Ta3N5 nanoparticles, but it did drastically improve the dispersion of the photocatalysts in the solution. This study proposes the use of an inert support in photocatalytic reactors to improve ease of handling the powder photocatalyst for gas-phase photocatalysis and the suspension of the solution, controlling nature of light harvesting and degree of scattering of the photoreactor. © 2013 Elsevier Ltd. All rights reserved.

  11. Microstructures and Surface Stabilities of {Ni-0.4C-6Ta- xCr, 0 ≤ x ≤ 50 Wt Pct} Cast Alloys at High Temperature

    Science.gov (United States)

    Berthod, Patrice

    2018-06-01

    Nickel-based cast alloys rich in chromium and reinforced by TaC carbides are potentially very interesting alloys for applications at elevated temperatures. Unfortunately, unlike cobalt-chromium and iron-chromium alloys, it is difficult to obtain exclusively TaC as primary carbides in Ni-Cr alloys. In alloys containing 30 wt pct Cr tantalum, carbides coexist with chromium carbides. The latter tend to weaken the alloy at elevated temperatures because they become rapidly spherical and then quickly lose their reinforcing effect. In this work, we attempted to stabilize TaC as a single carbide phase by testing different chromium contents in the [0, 50 wt pct] range. Six alloys containing 0.4C and 6Ta, weight contents corresponding to equivalent molar contents, were elaborated by foundry, and their as-cast microstructures were characterized. Samples of all alloys were exposed to 1127 °C and 1237 °C for 24 hours to characterize their stabilized microstructures. The surface fractions of chromium carbides and tantalum carbides were measured by image analysis, and their evolutions vs the chromium content were studied. For the chosen C and Ta contents, it appears that obtaining TaC only is possible by decreasing the chromium content to 10 wt pct. At the same time, TaC fractions are unfortunately too low because a large portion of tantalum integrates into the solid solution in the matrix. A second consequence is a critical decrease in oxidation resistance. Other possible methods to stabilize TaC as a single carbide are evocated, such as the simultaneous increase in Ta and decrease in chromium from 30 wt pct Cr.

  12. Crystallization and atomic diffusion behavior of high coercive Ta/Nd-Fe-B/Ta-based permanent magnetic thin film

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Na; Zhang, Xiao; You, Caiyin; Fu, Huarui [Xi' an University of Technology, School of Materials Science and Engineering, Xi' an (China); Shen, Qianlong [Logistics University of People' s Armed Police Force, Tianjin (China)

    2017-06-15

    A high coercivity of about 20.4 kOe was obtained through post-annealing the sputtered Ta/Nd-Fe-B/Ta-based permanent magnetic thin films. Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analyses were performed to investigate the crystallization and atomic diffusion behaviors during post-annealing. The results show that the buffer and capping Ta layers prefered to intermix with Fe and B atoms, and Nd tends to be combined with O atoms. The preferred atomic combination caused the appearance of the soft magnetic phase of Fe-Ta-B, resulting in a kink of the second quadratic magnetic hysteresis loop. The preferred atomic diffusion and phase formation of the thin films were well explained in terms of the formation enthalpy of the various compounds. (orig.)

  13. Pre-Test Analysis Predictions for the Shell Buckling Knockdown Factor Checkout Tests - TA01 and TA02

    Science.gov (United States)

    Thornburgh, Robert P.; Hilburger, Mark W.

    2011-01-01

    This report summarizes the pre-test analysis predictions for the SBKF-P2-CYL-TA01 and SBKF-P2-CYL-TA02 shell buckling tests conducted at the Marshall Space Flight Center (MSFC) in support of the Shell Buckling Knockdown Factor (SBKF) Project, NASA Engineering and Safety Center (NESC) Assessment. The test article (TA) is an 8-foot-diameter aluminum-lithium (Al-Li) orthogrid cylindrical shell with similar design features as that of the proposed Ares-I and Ares-V barrel structures. In support of the testing effort, detailed structural analyses were conducted and the results were used to monitor the behavior of the TA during the testing. A summary of predicted results for each of the five load sequences is presented herein.

  14. Phase evaluation of YSZ upon doping with Ta"5"+, Ti"4"+ and Ca"2"+ with combined Raman and XRD analysis

    International Nuclear Information System (INIS)

    Bhattacharya, A.; Shklover, V.; Wermelinger, T.

    2012-01-01

    To improve the phase stability of 7YSZ (7 wt%-Y_2O_3-doped ZrO_2), it has been doped with larger (Ca"2"+) and smaller (Ti"4"+ or Ta"5"+) ions. Complementary Raman and XRD studies of these stabilized systems have been performed. The tetragonal symmetry of the Ta"5"+-ion-doped YSZ sample and the Ti"4"+-doped YSZ sample, and the cubic symmetry of Ca"2"+-doped YSZ have been confirmed both by means of XRD and Raman analyses. Raman scattering measurements show shifts of characteristic peaks when the YSZ is doped with Ta"5"+, Ti"4"+ and Ca"2"+ cations. The peak shift increased with increasing dopant concentration in the ZrO_2 lattice. The Ta-doped YSZ sample heat-treated below 1500 C contained some YTaO_4 phase, which was confirmed by means of XRD as well as by Raman spectroscopy. The effect of Ca"2"+ ion doping on the Raman peak shift was much higher than that of Y"3"+ ion doping. In this work it has been highlighted that Raman spectroscopy is a useful tool complementing XRD, for qualitative comparison of the doping effect on the lattice parameters of ZrO_2.

  15. Electrodeposition of Al-Ta alloys in NaCl-KCl-AlCl{sub 3} molten salt containing TaCl{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Kazuki; Matsushima, Hisayoshi; Ueda, Mikito, E-mail: mikito@eng.hokudai.ac.jp

    2016-12-01

    Highlights: • Electrodeposition of Al-Ta alloys in an AlCl{sub 3}-NaCl-KCl-TaCl{sub 5} melt was carried out. • We were obtained 72 at% Ta-Al alloy at 0.3 V. • Amorphous Ta-Al was formed in high Ta concentration. - Abstract: To form Al-Ta alloys for high temperature oxidation resistance components, molten salt electrolysis was carried out in an AlCl{sub 3}-NaCl-KCl melt containing TaCl{sub 5} at 423 K. The voltammogram showed two cathodic waves at 0.45 V and 0.7 V vs. Al/Al(III), which may correspond to reduction from Ta(V) to Ta(III) and from Ta(III) to tantalum metal, respectively. Electrodeposits of Al and Ta were obtained in the range from −0.05 to 0.3 V and the highest concentration of Ta in the electrodeposit was 72 at% at 0.3 V. With increasing Ta content in the alloy, the morphology of the electrodeposits became powdery and the particle size smaller.

  16. Combined experimental and theoretical assessments of the lattice dynamics and optoelectronics of TaON and Ta3N5

    KAUST Repository

    Nurlaela, Ela; Harb, Moussab; Del Gobbo, Silvano; Vashishta, Manish; Takanabe, Kazuhiro

    2015-01-01

    Presented herein is a detailed discussion of the properties of the lattice dynamic and optoelectronic properties of tantalum(V) oxynitride (TaON) and tantalum(V) nitride (Ta3N5), from experimental and theoretical standpoint. The active Raman and infra red (IR) frequencies of TaON and Ta3N5 were measured using confocal Raman and Fourier Transform Infrared spectroscopies (FTIR) and calculated using the linear response method within the density functional perturbation theory (DFPT). The detailed study leads to an exhaustive description of the spectra, including the symmetry of the vibrational modes. Electronic structures of these materials were computed using DFT within the range-separated hybrid HSE06 exchange–correlation formalism. Electronic and ionic contributions to the dielectric constant tensors of these materials were obtained from DFPT within the linear response method using the PBE functional. Furthermore, effective mass of photogenerated holes and electrons at the band edges of these compounds were computed from the electronic band structure obtained at the DFT/HSE06 level of theory. The results suggest that anisotropic nature in TaON and Ta3N5 is present in terms of dielectric constant and effective masses.

  17. Ta penetration into template-type porous low-k material during atomic layer deposition of TaN

    International Nuclear Information System (INIS)

    Furuya, Akira; Ohtsuka, Nobuyuki; Misawa, Kaori; Shimada, Miyoko; Ogawa, Shinichi

    2005-01-01

    Ta penetration into a planar template-type porous low-k film during atomic layer deposition of TaN has been investigated by evaluating relations between Ta penetration and number of deposition cycles, exposure time of Ta precursor per deposition cycle, substrate temperature, and porosity of the porous low-k. The precursors were pentakisdimethylaminotantalum [PDMAT:Ta(N(CH 3 ) 2 ) 5 ] and NH 3 . The porous low-k was a methylsiloxane (MSX) whose pore size in the maximum distribution and porosity of the porous low-k were 0-1.9 nm and 0%-47%. Depth profile of the Ta penetration was measured by transmission electron microscopy and energy dispersive x-ray spectroscopy. The amount of penetrated and the penetration depth depended on the porosity. It was found that the precursors penetrate into the MSX film dominantly by gas phase diffusion through pores connecting from the surface to the inside. Increased surface area of the MSX film due to the pores results in a depletion of precursor at the wafer edge, and that this depletion causes the penetration characteristics at the edge of wafer differ from those at the center of the wafer. Moreover, the thickness required for the pore sealing by additive liner deposition is discussed

  18. Modelling the mechanical behaviour of heterogeneous Ta/TA6V welded joints: behaviour and failure criteria

    International Nuclear Information System (INIS)

    Paris, Th.

    2008-12-01

    As laser welding of two different materials (heterogeneous welding) leads to a joint having a characteristic size close to the millimetre, i.e. much smaller than that of a structure, and as such a junction displays completely different mechanical properties because of the metallurgical transformations induced by intense thermal loading, the aim of this research thesis is to develop a behaviour model, flexible and robust enough, to represent all together the mechanical behaviours of the Ta, the TA6V and the melted zone. This model must be able to take plasticity and visco-plasticity into account, and also to provide a failure criterion through damage mechanics and its coupling with the behaviour. The author first reports the experimental characterization of the base materials (Ta and TA6V) by using tensile tests under different strain rates and different directions, relaxation tests and fatigue shear tests. He also characterizes the melted zone by describing the influence of a thermal treatment (induced by welding) on the formation of the melted zone, and by using different tests: four point bending on notched specimens, nano-indentation test, and longitudinal tensile test. In a second part, the author develops the model within the framework of continuum thermodynamics, and explores the numerical issues. The last part deals with the validation of the model for the concerned materials (Ta and TA6V) and melted zone

  19. Combined experimental and theoretical assessments of the lattice dynamics and optoelectronics of TaON and Ta3N5

    KAUST Repository

    Nurlaela, Ela

    2015-06-15

    Presented herein is a detailed discussion of the properties of the lattice dynamic and optoelectronic properties of tantalum(V) oxynitride (TaON) and tantalum(V) nitride (Ta3N5), from experimental and theoretical standpoint. The active Raman and infra red (IR) frequencies of TaON and Ta3N5 were measured using confocal Raman and Fourier Transform Infrared spectroscopies (FTIR) and calculated using the linear response method within the density functional perturbation theory (DFPT). The detailed study leads to an exhaustive description of the spectra, including the symmetry of the vibrational modes. Electronic structures of these materials were computed using DFT within the range-separated hybrid HSE06 exchange–correlation formalism. Electronic and ionic contributions to the dielectric constant tensors of these materials were obtained from DFPT within the linear response method using the PBE functional. Furthermore, effective mass of photogenerated holes and electrons at the band edges of these compounds were computed from the electronic band structure obtained at the DFT/HSE06 level of theory. The results suggest that anisotropic nature in TaON and Ta3N5 is present in terms of dielectric constant and effective masses.

  20. Subsolidus phase relations of the SrO-Ta2O5-CuO system at 900 °C in air

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude

    2009-01-01

    The subsolidus phase relations of the SrO–Ta2O5–CuO system were investigated in air. The samples were equilibrated at 900 °C. The ternary oxide Sr3Ta2CuO9 compound is stable under these conditions. This phase presents a solid solution range, its actual composition being Sr3Ta2−xCu1+xO9+δ with 0.......0 ≤ x ≤ 0.2. Up to about 5 at.% Cu can be incorporated in the Sr3−xTa1+xO5.5+δ phase. Similarities with the SrO–Nb2O5–CuO system are discussed....

  1. Yellow light emission from Ta2O5:Er, Eu, Ce thin films deposited using a simple co-sputtering method

    Directory of Open Access Journals (Sweden)

    K. Miura

    2015-01-01

    Full Text Available Erbium, europium, and cerium co-doped tantalum oxide (Ta2O5:Er, Eu, Ce thin films were prepared using a simple co-sputtering method, and yellow light emission was observed by the naked eye from a sample annealed at 900 °C for 20 min. The hexagonal Ta2O5 phase is very important, but the hexagonal CeTa7O19 phase should be avoided to obtain strong yellow light emission from Ta2O5:Er, Eu, Ce films. The co-sputtered films can be used as high-refractive-index and yellow-light-emitting materials of autocloned photonic crystals that can be applied to novel light-emission devices, and they will also be used as anti-reflection and down-conversion layers toward high-efficiency silicon solar cells.

  2. Meltability in system of K2TaF7-NaF-NaCl-KCl

    International Nuclear Information System (INIS)

    Kartsev, V.E.; Kovalev, F.V.; Korshunov, B.G.

    1975-01-01

    Thermographic and visual-polythermal techniques were used to study the meltability in K 2 TaF 7 -NaF-NaCl-KCl system. The tetrahedron-forming sections NaF-NaCl-K 2 TaF 7 xKCl and NaF-K 2 TaF 7 xKCl-2K 2 TaF 7 xNaCl divide the concentration tetrahedron into three particular tetrahedra: NaF-K 2 TaF 7 xKCl-2K 2 TaF 7 xNaCl-K 2 TaF 7 , NaF-NaCl-K 2 TaF 7 xKCl-2K 2 TaF 7 xaCl, and NaF-NaCl-KCl-K 2 TaF 7 xKCl. Non-variant equilibrium points in all of the particular four-component systems have been determined

  3. The structure of Ti-Ta welded joint and microhardness distribution over the cross section

    Science.gov (United States)

    Fomin, Aleksandr A.; Koshuro, Vladimir A.; Egorov, Ivan S.; Shelkunov, Andrey Yu.; Zakharevich, Andrey M.; Steinhauer, Natalia N.; Rodionov, Igor V.

    2018-04-01

    In order to create highly efficient medical systems and measuring biosensors, an approach is frequently used, in which the constructive basis of the product is made of a high-strength biocompatible material (titanium, stainless steel), and the functional layer is made of a more expensive metal (Ta, Zr, Au, Pt, etc.) or ceramics (Ta2O5, ZrO2, CaTiO3, etc.). For a strong connection, e.g. titanium with tantalum, it is proposed to use diffusion butt welding. The heat generated by passing electric current (I is not less than 1.95-2.05 kA, P - not less than 9 kW, t = 250-1000 ms) and applied pressure (30-50 MPa) ensure an integral connection. To improve the quality of the joint, i.e. to exclude cracks and tightness, it is necessary to choose the right combination of the thickness of the welded parts. It was established that when titanium (2 mm thick) and tantalum (0.1-0.5 mm) are combined, a better Ti-Ta welded joint is formed when tantalum foil is used (0.5 mm). Here the distribution of hardness over the cross section of the sample, including the welding areas, is uniform and has no extremely high residual stresses of the tensile type.

  4. Optimization of urea-EnFET based on Ta2O5 layer with post annealing.

    Science.gov (United States)

    Lue, Cheng-En; Yu, Ting-Chun; Yang, Chia-Ming; Pijanowska, Dorota G; Lai, Chao-Sung

    2011-01-01

    In this study, the urea-enzymatic field effect transistors (EnFETs) were investigated based on pH-ion sensitive field effect transistors (ISFETs) with tantalum pentoxide (Ta(2)O(5)) sensing membranes. In addition, a post N(2) annealing was used to improve the sensing properties. At first, the pH sensitivity, hysteresis, drift, and light induced drift of the ISFETs were evaluated. After the covalent bonding process and urease immobilization, the urea sensitivity of the EnFETs were also investigated and compared with the conventional Si(3)N(4) sensing layer. The ISFETs and EnFETs with annealed Ta(2)O(5) sensing membranes showed the best responses, including the highest pH sensitivity (56.9 mV/pH, from pH 2 to pH 12) and also corresponded to the highest urea sensitivity (61 mV/pC(urea), from 1 mM to 7.5 mM). Besides, the non-ideal factors of pH hysteresis, time drift, and light induced drift of the annealed samples were also lower than the controlled Ta(2)O(5) and Si(3)N(4) sensing membranes.

  5. Optimization of Urea-EnFET Based on Ta2O5 Layer with Post Annealing

    Directory of Open Access Journals (Sweden)

    Chao-Sung Lai

    2011-04-01

    Full Text Available In this study, the urea-enzymatic field effect transistors (EnFETs were investigated based on pH-ion sensitive field effect transistors (ISFETs with tantalum pentoxide (Ta2O5 sensing membranes. In addition, a post N2 annealing was used to improve the sensing properties. At first, the pH sensitivity, hysteresis, drift, and light induced drift of the ISFETs were evaluated. After the covalent bonding process and urease immobilization, the urea sensitivity of the EnFETs were also investigated and compared with the conventional Si3N4 sensing layer. The ISFETs and EnFETs with annealed Ta2O5 sensing membranes showed the best responses, including the highest pH sensitivity (56.9 mV/pH, from pH 2 to pH 12 and also corresponded to the highest urea sensitivity (61 mV/pCurea, from 1 mM to 7.5 mM. Besides, the non-ideal factors of pH hysteresis, time drift, and light induced drift of the annealed samples were also lower than the controlled Ta2O5 and Si3N4 sensing membranes.

  6. Risk modification of colorectal cancer susceptibility by interleukin-8 -251T>A polymorphism in Malaysians.

    Science.gov (United States)

    Mustapha, Mohd Aminudin; Shahpudin, Siti Nurfatimah Mohd; Aziz, Ahmad Aizat Abdul; Ankathil, Ravindran

    2012-06-07

    To investigate the allele and genotype frequencies and associated risk of interleukin (IL)-8 -251T>A polymorphism on colorectal cancer (CRC) susceptibility risk. Peripheral blood samples of 255 normal controls and 255 clinically and histopathologically confirmed CRC patients were genotyped for IL-8 -251T>A polymorphism employing allele-specific polymerase chain reaction. The relative association of variant allele and genotypes with CRC susceptibility risk was determined by calculating the odds ratios (ORs). Corresponding χ² tests on the CRC patients and controls were carried out and 95% confidence intervals (CIs) were determined using Fisher's exact test. The allele frequencies and its risk association were calculated using FAMHAP, haplotype association analysis software. On comparing the frequencies of genotypes of patients and controls, the homozygous variant AA was significantly higher in CRC patients (P = 0.002) compared to controls. Investigation on the association of the polymorphic genotypes with CRC susceptibility risk, showed that the homozygous variant IL-8 -251AA had a significantly increased risk with OR 3.600 (95% CI: 1.550-8.481, P = 0.001). In the case of allele frequencies, variant allele A of IL-8 -251 showed a significantly increased risk of CRC predisposition with OR 1.32 (95% CI: 1.03-1.69, P = 0.003). Variant allele and genotype of IL-8 (-251T>A) was significantly associated with CRC susceptibility risk and could be considered as a high-risk variant for CRC predisposition.

  7. Crystal growth and spectroscopic characterization of Yb3+:LiTaO3

    International Nuclear Information System (INIS)

    Gruber, John B.; Allik, Toomas H.; Sardar, Dhiraj K.; Yow, Raylon M.; Scripsick, Michael; Wechsler, Barry

    2006-01-01

    Spectroscopic properties are presented for Yb 3+ incorporated into single crystals of LiTaO 3 grown by the top-seeded solution growth method. From an analysis of the absorption and fluorescence spectra, we are able to determine the Stark-level components of the 2 F 7/2 (the ground-state multiplet manifold) and the 2 F 5/2 (the excited-state multiplet manifold of Yb 3+ (4f 13 )). The room-temperature fluorescence lifetime of 2 F 5/2 is 678μs as measured on a thin sample to reduce possibilities for reabsorption. Spectral comparisons of Yb 3+ -doped LiTaO 3 and LiNbO 3 are drawn. The crystal-field splitting of Yb 3+ (4f 13 ) in both crystal hosts is modeled using a set of crystal-field splitting parameters, B nm , determined from a recent spectroscopic analysis of Er 3+ (4f 11 ) in LiNbO 3 . Without adjustment of the B nm parameters, the model predicts the Stark-level energy and the symmetry label for each level in reasonable agreement with the experimental values. Less photorefractive than its niobate cousin, LiTaO 3 has potential for use in numerous integrated electro-optical circuits and devices

  8. Nanospherical composite of WO{sub 3} wrapped NaTaO{sub 3}: Improved photodegradation of tetracycline under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Lingnan; Lang, Junyu; Wang, Shuwei; Chai, Zhanli; Su, Yiguo; Wang, Xiaojing, E-mail: wang_xiao_jing@hotmail.com

    2016-12-01

    Graphical abstract: - Highlights: • A novel ternary NaTaO{sub 3}@WO{sub 3} photocatalyst was successfully fabricated. • NaTaO{sub 3}@WO{sub 3} composites exhibited spherical assemblies with fine WO{sub 3} nanosheets wrapped on the cube NaTaO{sub 3} nanoparticles. • NaTaO{sub 3}@WO{sub 3} showed the enhanced photocatalytic performance in the tetracycline hydrochloride degradation under visible light irradiation. • An adsorption−degradation photocatalytic mechanism promoted through a Z-type heterojunction was proposed. - Abstract: In this paper, WO{sub 3}-wrapped NaTaO{sub 3} nanospheres photocatalysts with different W/Ta molar ratios were successfully prepared via a facile hydrothermal method. The samples were characterized by X-ray diffraction, transmission and scan electron microscopy, X-ray photoelectron spectroscopy, FT-IR spectrum, UV−vis diffuse reflectance spectroscopy, and Barrett−Emmett−Teller technique. The photocatalytic activities for degrading tetracycline hydrochloride under visible light irradiation were examined. The results indicated that the as-prepared NaTaO{sub 3}@WO{sub 3} photocatalysts showed the obvious enhancement in the tetracycline hydrochloride degradation ratio, compared with the pure NaTaO{sub 3} and WO{sub 3} under visible light irradiation. The optimum percentage of NaTaO{sub 3}@WO{sub 3} composites with a 60.88% degradation rate was W:Ta = 0.3:1 in mole, which was mainly attributed to the effective separation of the photo-generated electron and hole as well as the expanding of the absorption edge to the visible region due to the spherical heterojunction by wrapping WO{sub 3} on the surface of NaTaO{sub 3}. The radicals trapping experiments demonstrated that there were multiple active species during the degrading process of TC. The possible mechanism of tetracycline hydrochloride degradation by NaTaO{sub 3}@WO{sub 3} composite was also proposed.

  9. Developmental changes in leaf phenolics composition from three artichoke cvs. (Cynara scolymus) as determined via UHPLC-MS and chemometrics.

    Science.gov (United States)

    El Senousy, Amira S; Farag, Mohamed A; Al-Mahdy, Dalia A; Wessjohann, Ludger A

    2014-12-01

    The metabolomic differences in phenolics from leaves derived from 3 artichoke cultivars (Cynara scolymus): American Green Globe, French Hyrious and Egyptian Baladi, collected at different developmental stages, were assessed using UHPLC-MS coupled to chemometrics. Ontogenic changes were considered as leaves were collected at four different time intervals and positions (top and basal) during artichoke development. Unsupervised principal component analysis (PCA) and supervised orthogonal projection to latent structures-discriminant analysis (O2PLS-DA) were used for comparing and classification of samples harvested from different cultivars at different time points and positions. A clear separation among the three investigated cultivars was revealed, with the American Green Globe samples found most enriched in caffeic acid conjugates and flavonoids vs. other cultivars. Furthermore, these metabolites also showed a marked effect on the discrimination between leaf samples from cultivars harvested at different positions, regardless of the plant age. Metabolite absolute quantifications further confirmed that discrimination was mostly influenced by phenolic compounds, namely caffeoylquinic acids and flavonoids. This study demonstrates an effect of artichoke leaf position, regardless of plant age, on its secondary metabolites composition. To the best of our knowledge, this is the first report for compositional differences among artichoke leaves, based on their positions, via a metabolomic approach and suggesting that top positioned artichoke leaves present a better source of caffeoylquinic acids, compared to basal ones. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Enhanced post-annealing stability of perpendicular Ta/CoFeB/Mg/MgO multilayers by inhibiting Ta diffusion

    International Nuclear Information System (INIS)

    Li, Xu-Jing; Jiang, Shao-Long; Zhang, Jing-Yan; Liu, Qian-Qian; Liu, Yi-Wei; Zhao, Jian-Cheng; Wu, Zheng-Long; Feng, Chun; Li, Ming-Hua; Yu, Guang-Hua

    2016-01-01

    Graphical abstract: To reveal the underlying mechanism of Mg influence on the enhanced post-annealing stability of perpendicular Ta/CoFeB/Mg/MgO multilayers, the X-ray photoelectron spectroscopy analysis have been performed. It is found that a certain amount of Mg interlayer at the CoFeB/MgO interface could prevent the Ta oxidation to some extent due to the oxygen deficit MgO_x (x < 1), and consequently lower the diffusion motivation of Ta from the bottom layer to the CoFeB/MgO interfaces to some extent during the annealing process. The prevention of Ta diffusion realizes the effective hybridization of Fe and O at the CoFeB/MgO interface and maintains interfacial magnetic anisotropy (K_C_o_F_e_B_/_M_g_O). As a result, the perpendicular magnetic anisotropy at high annealing temperatures was maintained. - Highlights: • High annealing stability of perpendicular Ta/CoFeB/Mg/MgO multilayers was realized. • X-ray photoelectron spectroscopy analysis has been performed to explore the reasons. • The prevention of Ta diffusion was realized by introducing Mg at the CoFeB/MgO interface. - Abstracts: To reveal the underlying mechanism of Mg influence on the enhanced post-annealing stability of perpendicular Ta/CoFeB/Mg/MgO multilayers, the X-ray photoelectron spectroscopy analysis has been performed. It is found that a certain amount of Mg interlayer at the CoFeB/MgO interface could prevent the Ta oxidation, and consequently lower the diffusion motivation of Ta from the bottom layer to the CoFeB/MgO interfaces to some extent in the annealing process. The prevention of Ta diffusion realizes the effective hybridization of Fe and O at the CoFeB/MgO interface and maintains interfacial magnetic anisotropy (KCoFeB/MgO). As a result, the perpendicular magnetic anisotropy at high annealing temperatures is maintained

  11. Enhanced post-annealing stability of perpendicular Ta/CoFeB/Mg/MgO multilayers by inhibiting Ta diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xu-Jing; Jiang, Shao-Long; Zhang, Jing-Yan; Liu, Qian-Qian; Liu, Yi-Wei; Zhao, Jian-Cheng [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Wu, Zheng-Long [Analytical and Testing Center, Beijing Normal University, Beijing 100875 (China); Feng, Chun, E-mail: fengchun@ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Li, Ming-Hua [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Yu, Guang-Hua, E-mail: ghyu@mater.ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China)

    2016-03-01

    Graphical abstract: To reveal the underlying mechanism of Mg influence on the enhanced post-annealing stability of perpendicular Ta/CoFeB/Mg/MgO multilayers, the X-ray photoelectron spectroscopy analysis have been performed. It is found that a certain amount of Mg interlayer at the CoFeB/MgO interface could prevent the Ta oxidation to some extent due to the oxygen deficit MgO{sub x} (x < 1), and consequently lower the diffusion motivation of Ta from the bottom layer to the CoFeB/MgO interfaces to some extent during the annealing process. The prevention of Ta diffusion realizes the effective hybridization of Fe and O at the CoFeB/MgO interface and maintains interfacial magnetic anisotropy (K{sub CoFeB/MgO}). As a result, the perpendicular magnetic anisotropy at high annealing temperatures was maintained. - Highlights: • High annealing stability of perpendicular Ta/CoFeB/Mg/MgO multilayers was realized. • X-ray photoelectron spectroscopy analysis has been performed to explore the reasons. • The prevention of Ta diffusion was realized by introducing Mg at the CoFeB/MgO interface. - Abstracts: To reveal the underlying mechanism of Mg influence on the enhanced post-annealing stability of perpendicular Ta/CoFeB/Mg/MgO multilayers, the X-ray photoelectron spectroscopy analysis has been performed. It is found that a certain amount of Mg interlayer at the CoFeB/MgO interface could prevent the Ta oxidation, and consequently lower the diffusion motivation of Ta from the bottom layer to the CoFeB/MgO interfaces to some extent in the annealing process. The prevention of Ta diffusion realizes the effective hybridization of Fe and O at the CoFeB/MgO interface and maintains interfacial magnetic anisotropy (KCoFeB/MgO). As a result, the perpendicular magnetic anisotropy at high annealing temperatures is maintained.

  12. Hydriding and dehydriding rates of Mg, Mg-10TaF5, and Mg-10NbF5 prepared via reactive mechanical grinding

    Science.gov (United States)

    Song, Myoung Youp; Kwak, Young Jun; Lee, Seong Ho; Park, Hye Ryoung

    2015-01-01

    In this work, TaF5 and NbF5 were chosen as additives to enhance the hydriding and dehydriding rates of Mg. Mg, Mg-10TaF5, and Mg-10NbF5 samples were prepared by reactive mechanical grinding. The hydriding and dehydriding properties of the samples were then examined. Mg-10TaF5 had the largest amount of hydrogen absorbed for 30 min and the highest initial dehydriding rate after incubation period, followed in order by Mg-10NbF5, and Mg. At 593 K under 12 bar H2 at the first cycle, Mg-10TaF5 absorbed 3.63 wt% H for 5 min and 4.53 wt% H for 30 min. At 593 K under 1.0 bar H2 at the first cycle, Mg-10TaF5 desorbed 0 wt% H for 2.5 min, 0.59 wt% H for 5 min, 3.42 wt% H for 30 min, and 4.24 wt% H for 60 min. The reactive mechanical grinding of Mg with TaF5 or NbF5 is believed to have facilitated the nucleation and to have decreased the diffusion distances of hydrogen atoms. These two effects are believed to have increased the hydriding and dehydriding rates of Mg. The MgF2 and Ta2H formed in Mg-10TaF5, and the MgF2, NbH2, and NbF3 formed in Mg-10NbF5 are considered to have enhanced both of these effects.

  13. Local structure and defect chemistry of [(SnSe)1.15]m(TaSe2) ferecrystals – A new type of layered intergrowth compound

    International Nuclear Information System (INIS)

    Grosse, Corinna; Atkins, Ryan; Kirmse, Holm; Mogilatenko, Anna; Neumann, Wolfgang; Johnson, David C.

    2013-01-01

    Highlights: •The crystal structure of [(SnSe) 1.15 ] m (TaSe 2 ) ferecrystals was analyzed by TEM. •The layers exhibit turbostratic disorder, but we also observed a local ordering. •The structures of the SnSe and TaSe 2 layers are similar to binary SnSe and 2H-TaSe 2 . •An increasing in-plane SnSe grain size with increasing m was observed. •Defect areas with missing, substituted or additional layers were found. -- Abstract: The atomic structure of the family of ferecrystals [(SnSe) 1.15 ] m (TaSe 2 ) (m = 1, 3, and 6) was investigated by means of transmission electron microscopy. The tantalum in the TaSe 2 layers was observed to have trigonal prismatic coordination similar to that found in the 2H polytype of bulk TaSe 2 . The structure of the SnSe constituent was found to be similar to that of orthorhombic α-SnSe. In the compounds with m = 1 and m = 3, regions with a local ordering of the layers along a commensurate axis, similar to the ordering in conventional misfit layer compounds, were observed. However, on a longer range the ferecrystals were found to exhibit a turbostratically disordered structure. Stacking defects were occasionally found in the samples in which a layer is interrupted and the surrounding layers are bent around these defects, while maintaining abrupt interfaces instead of interdiffusing. Volume defects were found in one sample of [(SnSe) 1.15 ] 1 (TaSe 2 ) 1 in which a SnSe layer locally substitutes a part of a TaSe 2 layer without interrupting the surrounding layers

  14. Mesoporous Nb and Ta Oxides: Synthesis, Characterization and Applications in Heterogeneous Acid Catalysis

    Science.gov (United States)

    Rao, Yuxiang Tony

    In this work, a series of mesoporous Niobium and Tantalum oxides with different pore sizes (C6, C12, C18 , ranging from 12A to 30 A) were synthesized using the ligand-assisted templating approach and investigated for their activities in a wide range of catalytic applications including benzylation, alkylation and isomerization. The as-synthesized mesoporous materials were characterized by nitrogen adsorption, powder X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), and solid-state Nuclear magnetic resonance (NMR) techniques. In order to probe into the structural and coordination geometry of mesoporous Nb oxide and in efforts to make meaningful comparisons of mesoporous niobia prepared by the amine-templating method with the corresponding bulk sol-gel prepared Nb2O5 phase, 17O magic-angle-spinning solid-state NMR studies were conducted. The results showed a very high local order in the mesoporous sample. The oxygen atoms are coordinated only as ONb 2 in contrast with bulk phases in which the oxygen atoms are always present in a mixture of ONb2 and ONb3 coordination environments. To enhance their surface acidities and thus improve their performance as solid acid catalysts in the acid-catalyzed reactions mentioned above, pure mesoporous Nb and Ta oxides were further treated with 1M sulfuric acid or phosphoric acid. Their surface acidities before and after acid treatment were measured by Fourier transform infraRed (FT IR), amine titration and temperature programmed desorption of ammonia (NH3-TPD). Results obtained in this study showed that sulfated mesoporous Nb and Ta oxides materials possess relative high surface areas (up to 612 m 2/g) and amorphous wormhole structure. These mesoporous structures are thus quite stable to acid treatment. It was also found that Bronsted (1540 cm-1) and Lewis (1450 cm-1) acid sites coexist in a roughly 50:50 mixture

  15. Combined influence of fluorine doping and vacuum annealing on the electrical properties of ZnO:Ta films

    Energy Technology Data Exchange (ETDEWEB)

    Subha, K. [Materials Science Research Laboratory, PG and Research Department of Physics, AVVM Sri Pushpam College (Autonomous), Poondi, Thanjavur, 613 503, Tamil Nadu (India); Research Department of Physics, Kunthavai Naachiyaar Govt. Arts College for Women (Autonomous), Thanjavur, 613 007, Tamil Nadu (India); Ravichandran, K., E-mail: kkr1365@yahoo.com [Materials Science Research Laboratory, PG and Research Department of Physics, AVVM Sri Pushpam College (Autonomous), Poondi, Thanjavur, 613 503, Tamil Nadu (India); Sriram, S. [School of Electrical and Electronics Engineering, SASTRA University, Thanjavur, 613 401, Tamil Nadu (India)

    2017-07-01

    Highlights: • First report on combined effect of F doping and annealing on resistivity of ZnO:Ta films. • Various possible incorporation mechanisms of tantalum and fluorine are addressed. • Theoretical validation of Ta and F incorporation by DFT analysis is done. • Quality factor comparable with those obtained by physical methods is achieved.. - Abstract: In this study, our main focus is to investigate the effects of F doping and post deposition annealing (air and vacuum) on the optical and electrical characteristics of tantalum doped zinc oxide films (ZnO:Ta). A cost-effective, automated jet nebulizer spray pyrolysis technique is adopted to deposit the ZnO:Ta:F films. The doping level of Ta is kept constant (1 at.%) and that of F is varied from 5 to 20 at.% in steps of 5 at.%. The electrical resistivity of the as-deposited films decreases for 10 at.% of F concentration. The resistance increases thereafter. The same trend is also observed in annealed films. The reasons for these variations are addressed based on the effective F incorporation into the ZnO lattice and annealing atmosphere with the help of XRD, FESEM, AFM and PL studies. The incorporation of the dopants was confirmed from XPS and EDX analyses and the DFT studies show that the incorporation of the dopants does not affect the stability of the ZnO lattice. Vacuum-annealed films show better electrical properties over the as-deposited and air-annealed counterparts, though their transparency is affected marginally. A minimum resistivity of 0.81 × 10{sup −3} Ω cm and an enhanced quality factor of 2.265 × 10{sup −4} (Ω/sq){sup −1} are achieved for the vacuum-annealed films having Ta + F doping levels as 1 + 10 at.%. These results make this sample a desirable candidate for transparent electrode applications.

  16. Electric field gradients at 181Ta sites in HfOx

    International Nuclear Information System (INIS)

    Darriba, G.N.; Rodriguez, A.M.; Saitovitch, H.; Silva, P.R.J.; Pasquevich, A.F.

    2007-01-01

    In the present work we report preliminary results about the possibility to study properties of the order-disorder transition in HfO x solid solutions via the determination of the electric field gradient (EFG) at 181 Ta radioactive probes. Oxygen solution into the metal was achieved by arc melting stoichiometric amounts of metallic Hf and HfO 2 under argon atmosphere. Samples of HfO x with x=0.1 and 0.2 were prepared. Two types of samples were used for the perturbed angular correlation (PAC) experiments by doping alternatively with 181 Ta, by neutron irradiation, the metallic Hf or the hafnium oxide. The PAC results on both samples were identical, with disappearing hyperfine signals of the metal and the oxide, showing a complete diffusion of the probes independent of the way of doping. The PAC signal of the HfO x solid solution consisted in a wide distribution of EFGs due to the oxygen disorder. This scheme held even after long thermal treatments at high temperature (several days at 1273K). Annealing treatments at moderate temperature (600K) were also made. In these cases the samples were cooling at a very low rate. These results, together with those obtained by measuring samples below and above the order temperature are reported

  17. Lithiotantite, ideally LiTa3O8

    Directory of Open Access Journals (Sweden)

    Aba C. Persiano

    2012-05-01

    Full Text Available Lithiotantite (lithium tritantalum octaoxide and lithiowodginite are natural dimorphs of LiTa3O8, corresponding to the laboratory-synthesized L-LiTa3O8 (low-temperature form and M-LiTa3O8 (intermediate-temperature form phases, respectively. Based on single-crystal X-ray diffraction data, this study presents the first structure determination of lithiotantite from a new locality, the Murundu mine, Jenipapo District, Itinga, Minas Gerais, Brazil. Lithiotantite is isotypic with LiNb3O8 and its structure is composed of a slightly distorted hexagonal close-packed array of O atoms stacked in the [-101] direction, with the metal atoms occupying half of the octahedral sites. There are four symmetrically non-equivalent cation sites, with three of them occupied mainly by (Ta5+ + Nb5+ and one by Li+. The four distinct octahedra share edges, forming two types of zigzag chains (A and B extending along the b axis. The A chains are built exclusively of (Ta,NbO6 octahedra (M1 and M2, whereas the B chains consist of alternating (Ta,NbO6 and LiO6 octahedra (M3 and M4, respectively. The average M1—O, M2—O, M3—O and M4—O bond lengths are 2.011, 2.004, 1.984, and 2.188 Å, respectively. Among the four octahedra, M3 is the least distorted and M4 the most. The refined Ta contents at the M1, M2 and M3 sites are 0.641 (2, 0.665 (2, and 0.874 (2, respectively, indicating a strong preference of Ta5+ for M3 in the B chain. The refined composition of the crystal investigated is Li0.96Mn0.03Na0.01Nb0.82Ta2.18O8.

  18. Laminated structure in internally oxidized Ru-Ta coatings

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yung-I, E-mail: yichen@mail.ntou.edu.tw

    2012-12-01

    During the development of refractory alloy coatings for protective purposes at high temperature under oxygen-containing atmospheres, previous studies noted and examined the internal oxidation phenomenon for Mo-Ru and Ru-Ta coatings. The internally oxidized zone shows a laminated structure, consisting of alternating oxygen-rich and deficient layers stacked with a general orientation. Previous studies proposed a forming mechanism. To investigate in detail, Ru-Ta coatings were prepared with various rotating speeds of a substrate-holder. The coatings were annealed at 600 Degree-Sign C in an atmosphere continuously purged with 1% O{sub 2}-99% Ar mixed gas for 30 min. Transmission electron microscopy was used to examine the laminated-layer periods. Auger electron spectroscopy depth profiles certified the periodical variation of the related constituents. X-ray photoelectron spectroscopy proved the valence variation of Ta in the near surface, accompanied by the introduction of oxygen ions. The inward diffusion of oxygen was dominated by lattice diffusion. - Highlights: Black-Right-Pointing-Pointer Laminated Ru-Ta coatings consisted of a cyclical gradient concentration. Black-Right-Pointing-Pointer The as-deposited coatings showed a laminated structure with a period of 4-34 nm. Black-Right-Pointing-Pointer Internal oxidation of Ru-Ta coatings executed after annealing in 1% O{sub 2}-Ar atmosphere. Black-Right-Pointing-Pointer Oxygen inward diffusion was dominated by lattice diffusion.

  19. The potential capacities of Ta'ziyeh in Modern Imagism

    Directory of Open Access Journals (Sweden)

    A.M Nedai

    2009-03-01

    Full Text Available Ta'ziyeh as the most important method in religious and ritual theatre in Iran has many capabilities which can be used in modern visualization. The only element in this theatre which has been studied is distancing in performance styles. But by studying the existent versions of Ta'ziyehs, there are other elements for recognition and use, which has not still been studied. The relationship between religious and ritual theatre with Ta'ziyeh and also their main themes helps to identify these elements and their capabilities. Meanwhile, the presence of music as an expressive and performing element provides a basis which can be used in finding a new manner of expression in visual/dramatic works (such as music videos. Studying on such elements as time-place interlace, character replacement, functions of music, and their effects on audiences, shows that Ta'ziyeh has specific capabilities in visualization (even in Cinema and Media. This article, through capitalizing on this subject and introducing one paradigm (Moses and poor Pilgrim, and comparing two versions of it, tries to represent these capabilities, and illuminates Ta'ziyeh's abilities for modern (and even postmodern visualization.

  20. Gold nanoparticles embedded in Ta 2 O 5 /Ta 3 N 5 as active visible-light plasmonic photocatalysts for solar hydrogen evolution

    KAUST Repository

    Luo, Yujing; Liu, Xiaoming; Tang, Xinghua; Luo, Yan; Zeng, Qianyao; Deng, Xiaolei; Ding, Shaolei; Sun, Yiqun

    2014-01-01

    Here, we demonstrate a new recreating photocatalytic activity of a Nano Au/Ta2O5 composite for hydrogen evolution from water as a visible-light-responsive plasmonic photocatalyst by embedding Au nanoparticles in a Ta2O5 host lattice. The Nano Au/Ta2

  1. 75 FR 43564 - TA-W-71,483, Continental Airlines, Inc., Reservations Division, Houston, TX; TA-W-71,483A...

    Science.gov (United States)

    2010-07-26

    ... DEPARTMENT OF LABOR Employment and Training Administration TA-W-71,483, Continental Airlines, Inc., Reservations Division, Houston, TX; TA-W-71,483A, Continental Airlines, Inc., Reservations Division, Tampa, FL; TA-W-71,483B, Continental Airlines, Inc., Reservations Division, Salt Lake City, UT; Notice of...

  2. Highly Reproducible Automated Proteomics Sample Preparation Workflow for Quantitative Mass Spectrometry.

    Science.gov (United States)

    Fu, Qin; Kowalski, Michael P; Mastali, Mitra; Parker, Sarah J; Sobhani, Kimia; van den Broek, Irene; Hunter, Christie L; Van Eyk, Jennifer E

    2018-01-05

    Sample preparation for protein quantification by mass spectrometry requires multiple processing steps including denaturation, reduction, alkylation, protease digestion, and peptide cleanup. Scaling these procedures for the analysis of numerous complex biological samples can be tedious and time-consuming, as there are many liquid transfer steps and timed reactions where technical variations can be introduced and propagated. We established an automated sample preparation workflow with a total processing time for 96 samples of 5 h, including a 2 h incubation with trypsin. Peptide cleanup is accomplished by online diversion during the LC/MS/MS analysis. In a selected reaction monitoring (SRM) assay targeting 6 plasma biomarkers and spiked β-galactosidase, mean intraday and interday cyclic voltammograms (CVs) for 5 serum and 5 plasma samples over 5 days were samples repeated on 3 separate days had total CVs below 20%. Similar results were obtained when the workflow was transferred to a second site: 93% of peptides had CVs below 20%. An automated trypsin digestion workflow yields uniformly processed samples in less than 5 h. Reproducible quantification of peptides was observed across replicates, days, instruments, and laboratory sites, demonstrating the broad applicability of this approach.

  3. Model Development to Predict Phenological scale of Table Grapes (cvs. Thompson, Crimson and Superior Seedless and Red Globe using Growing Degree Days

    Directory of Open Access Journals (Sweden)

    Nicolas Verdugo-Vásquez

    2017-09-01

    Full Text Available Phenological models have been made mainly for winegrape cultivars, despite the economic importance of table grapes. The aim of this work was to develop and validate models for predicting phenological scales of table grapes (cvs. Thompson, Crimson and Superior Seedless and Red Globe grown under semi-arid conditions. Measurements of phenology were carried out weekly from budburst to harvest during four growing seasons (2009-2013. Phenology models were developed using the Mitscherlich monomolecular equation where the dependent and independent variables were the Eichhorn and Lorenz phenological (ELP scale modified by Coombe and the growing degree days (GDD, respectively. Results indicated that there were strong non-linear correlations between the ELP scale and GDD for the four cultivars with coefficient of determinations (R2 ranging between 0.97-0.99. Also, validation indicated that the models were able to predict ELP scale with a root mean square (RMSE and mean absolute error (MAE ranging between 2.1-2.4 and 1.35-1.69, respectively. The prediction variability (expressed in days was between 4.4-19.4 days, obtaining the best results for the flowering period. This study suggested that the phenological models based on GDD could be useful planning tools for farming, especially from budburst to veraison of table grape cultivars.

  4. Risk of miscarriage following amniocentesis and chorionic villus sampling: a systematic review of the literature.

    Science.gov (United States)

    Beta, Jaroslaw; Lesmes-Heredia, Cristina; Bedetti, Chiara; Akolekar, Ranjit

    2018-04-01

    The aim of this paper was to estimate the risk of miscarriage after amniocentesis or chorionic villus sampling (CVS) based on a systematic review of the literature. A search of Medline, Embase, and The Cochrane Library (2000-2017) was carried out to identify studies reporting complications following CVS or amniocentesis. The inclusion criteria for the systematic review were studies reporting results from large controlled studies (N.≥1000 invasive procedures) and those reporting data for pregnancy loss prior to 24 weeks' gestation. Data for cases that had invasive procedure and controls were inputted in contingency tables and risk of miscarriage was estimated for each study. Summary statistics were calculated after taking into account the weighting for each study included in the systematic review. Procedure-related risk of miscarriage was estimated as a weighted risk difference from the summary statistics for cases and controls. The electronic search from the databases yielded 2465 potential citations of which 2431 were excluded, leaving 34 studies for full-text review. The final review included 10 studies for amniocentesis and 6 studies for CVS, which were used to estimate risk of miscarriage in pregnancies that had an invasive procedure and the control pregnancies that did not. The procedure-related risk of miscarriage following amniocentesis was 0.35% (95% confidence interval [CI]: 0.07 to 0.63) and that following CVS was 0.35% (95% CI: -0.31 to 1.00). The procedure-related risks of miscarriage following amniocentesis and CVS are lower than currently quoted to women.

  5. Redetermination of Na(3)TaF(8).

    Science.gov (United States)

    Langer, Vratislav; Smrcok, Lubomír; Boca, Miroslav

    2010-09-01

    The crystal structure of trisodium octafluoridotantalate, Na(3)TaF(8), has been redetermined using diffractometer data collected at 153 K, resulting in more accurate bond distances and angles than obtained from a previous structure determination based on film data. The structure is built from layers running along [101], which are formed by distorted [TaF(8)] antiprisms and [NaF(6)] rectangular bipyramids sharing edges and corners. The individual layers are separated by eight-coordinated Na ions. Two atoms in the asymmetric unit are in special positions: the Ta atom is on a twofold axis in Wyckoff position 4e and one of the Na ions lies on an inversion centre in Wyckoff site 4d.

  6. FLEKSIGURNOST I (DEREGULACIJA TRŽIŠTA RADA

    Directory of Open Access Journals (Sweden)

    Sandra Laleta

    2016-01-01

    Full Text Available Predmet su ovoga rada radni odnosi i tržište rada u kontekstu fleksigurnosti. U radu se analizira novi vladavinski model, soft law, otvorene metode koordina- cije, europski socijalni model, inkluzivnost, kategorije koje su neraskidivo vezane uz fleksigurnost, radne odnose i tržište rada. Istražena su njihova obilježja i utjecaj na supranacionalnu regulativu, usporednopravna i hrvatska rješenja. Daje se i raščlamba nekih novih instituta tržišta rada (novi oblici uređenja radnog vremena, agencijski rad, mini-jobs. Poseban dio rada čini istraživanje (dereguliranja tržišta rada, novih modela zapošljavanja, kao i fleksigurnosti i hrvatskoga tržišta rada de lege lata te se daju prijedlozi de lege ferenda.

  7. Microstructural evolution and creep of Fe-Al-Ta alloys

    Energy Technology Data Exchange (ETDEWEB)

    Prokopcakova, Petra; Svec, Martin [Technical University of Liberec (Czech Republic). Dept. of Material Science; Palm, Martin [Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany). Structure and Nano-/Micromechanics of Materials

    2016-05-15

    The microstructural evolution in Fe-Al-Ta alloys containing 23 - 31 at.% Al and 1.5 - 2.2 at.% Ta has been studied in the temperature range 650 - 750 C by annealing for 1, 10, 100 and 1 000 h. The experiments confirm that in this temperature range the precipitation of the stable hexagonal C14 Laves phase is preceded by formation of coherent, metastable L2{sub 1} Heusler phase precipitates within the Fe-Al matrix. However, precipitates of C14 are observed after much shorter annealing times than previously assumed. Creep strength increases substantially with increasing Al content of the alloys because the solid solubility for Ta in the Fe-Al matrix increases with increasing Al content and solid-solution hardening contributes substantially to the observed high creep strength. It may therefore be that the microstructural changes during creep have no noticeable effect on creep strength.

  8. Microstructural evolution and creep of Fe-Al-Ta alloys

    International Nuclear Information System (INIS)

    Prokopcakova, Petra; Svec, Martin; Palm, Martin

    2016-01-01

    The microstructural evolution in Fe-Al-Ta alloys containing 23 - 31 at.% Al and 1.5 - 2.2 at.% Ta has been studied in the temperature range 650 - 750 C by annealing for 1, 10, 100 and 1 000 h. The experiments confirm that in this temperature range the precipitation of the stable hexagonal C14 Laves phase is preceded by formation of coherent, metastable L2 1 Heusler phase precipitates within the Fe-Al matrix. However, precipitates of C14 are observed after much shorter annealing times than previously assumed. Creep strength increases substantially with increasing Al content of the alloys because the solid solubility for Ta in the Fe-Al matrix increases with increasing Al content and solid-solution hardening contributes substantially to the observed high creep strength. It may therefore be that the microstructural changes during creep have no noticeable effect on creep strength.

  9. Method of treating Ti--Nb--Zr--Ta superconducting alloys

    International Nuclear Information System (INIS)

    Horiuchi, T.; Monju, Y.; Tatara, I.; Nagai, N.; Hisata, M.; Matsumoto, K.

    1975-01-01

    A superconducting alloy is formulated from 10 to 50 at. percent Ti, 20 to 50 at. percent Nb, 10 to 40 at. percent Zr, and 5 to 12 at. percent Ta. A Ti--Nb--Zr--Ta superconducting alloy with a fine, non-homogeneous structure is obtained by forming a β solid solution of Ti--Nb--Zr--Ta alloy by heating to a temperature within the β solid solution range, cooling, and then cold working the heated alloy. The cold worked alloy is heated to a temperature within the (β' + β'') alloy to maintain the peritectoid structure, cold worked, then heated to a temperature within the eutectoid range to form a multiphase alloy structure and then cooled and finally cold worked. (U.S.)

  10. Variable substrate temperature deposition of CoFeB film on Ta for manipulating the perpendicular coercive forces

    Energy Technology Data Exchange (ETDEWEB)

    Lakshmanan, Saravanan; Rao, Subha Krishna [Nanotechnology Research Centre, SRM University, Kattankulathur, Chennai 603203 (India); Muthuvel, Manivel Raja [Defence Metallurgical Research Laboratory (DMRL), Hyderabad 500058 (India); Chandrasekaran, Gopalakrishnan [Nanotechnology Research Centre, SRM University, Kattankulathur, Chennai 603203 (India); Therese, Helen Annal, E-mail: helen.a@ktr.srmuniv.ac.in [Nanotechnology Research Centre, SRM University, Kattankulathur, Chennai 603203 (India)

    2017-08-01

    Highlights: • Ta/CoFeB(50 nm)/Ta thin films were deposited at various substrate temperatures (T{sub s}). • CoFeB films deposited at T{sub s} such as RT, 450 °C, 475 °C and 500 °C exhibited perpendicular coercivity. • CoFeB deposited at 475 °C displayed a higher coercivity of 315 Oe and a low M{sub s} of 169 emu/cc. • The enhanced crystallization of CoFeB at the Ta/CoFeB interface results in higher H{sub c} (⟂). - Abstract: Magnetization of Ta/CoFeB/Ta trilayer films with thick layer of CoFeB deposited under different substrate temperatures (T{sub s}) via ultra-high vacuum DC sputtering technique has been measured with the applied magnetic field parallel and perpendicular to the plane of the film respectively to study the perpendicular coercive forces of the film. The samples were further analyzed for its structural, topological, morphological, and electrical transport properties. The core chemical states for the elements present in the CoFeB thin film were analyzed by XPS studies. Magnetization studies reveal the existence of perpendicular coercive forces in CoFeB films deposited only at certain temperatures such as RT, 450 °C, 475 °C and 500 °C. CoFeB film deposited at 475 °C exhibited a maximum coercivity of 315 Oe and a very low saturation magnetization (M{sub s}) of 169 emu/cc in perpendicular direction. This pronounced effect in perpendicular coercive forces observed for CoFeB475 could be attributed to the effect of temperature in enhancing the crystallization of the film at the Ta/CoFeB interfaces. However at temperatures higher than 475 °C the destruction of the Ta/CoFeB interface due to intermixing of Ta and CoFeB results in the disappearance of magnetic anisotropy.

  11. Closure certification report: TA-35 TSL-125 surface impoundment

    International Nuclear Information System (INIS)

    1991-01-01

    This closure report documents closure activities for the TA-35 TSL-125 surface impoundment and associated structures at Los Alamos National Laboratory (the Laboratory). Prior to formal approval of the closure plan, the decision was made to proceed with closure activities to prevent any further releases from the site following informal discussions with New Mexico Environment Department (NMED) personnel. The closure plan is a revision of the previously submitted draft dated July 1988. Clean closure of the TSL-125 site was accomplished through: Removal and proper disposal of all wastes contained within the surface impoundment system; Decontamination and/or removal and proper disposal of the surface impoundment, its associated structures, and contaminated soil underlying the impoundment area; Sampling and analysis of soil to determine the presence and concentrations of any hazardous constituents remaining in the soil at the TSL-125 site; and Demonstration through a risk assessment that any constituents remaining in the soil at the TSL-125 site pose no threat to human health and the environment. All remaining soil concentrations of hazardous constituents were below health-based action levels. Analytical results indicated that benzidine, n-nitrosodimethylamine, and n-nitrosodi-n-propylamine were not detected at or above their limits of quantitation and beryllium was not present at or above its laboratory detection limit. However, the limits of quantitation and detection for these constituents were greater than their calculated health-based action levels. To demonstrate that these constituents were not present, historical data was researched and it was determined that the constituents were not utilized at the Building 125 site. 4 refs., 8 figs., 1 tab

  12. Cloning and Functional Analysis of MADS-box Genes, TaAG-A and TaAG-B, from a Wheat K-type Cytoplasmic Male Sterile Line

    Directory of Open Access Journals (Sweden)

    Wenlong Yang

    2017-06-01

    Full Text Available Wheat (Triticum aestivum L. is a major crop worldwide. The utilization of heterosis is a promising approach to improve the yield and quality of wheat. Although there have been many studies on wheat cytoplasmic male sterility, its mechanism remains unclear. In this study, we identified two MADS-box genes from a wheat K-type cytoplasmic male sterile (CMS line using homology-based cloning. These genes were localized on wheat chromosomes 3A and 3B and named TaAG-A and TaAG-B, respectively. Analysis of TaAG-A and TaAG-B expression patterns in leaves, spikes, roots, and stems of Chinese Spring wheat determined using quantitative RT-PCR revealed different expression levels in different tissues. TaAG-A had relatively high expression levels in leaves and spikes, but low levels in roots, while TaAG-B had relatively high expression levels in spikes and lower expression in roots, stems, and leaves. Both genes showed downregulation during the mononucleate to trinucleate stages of pollen development in the maintainer line. In contrast, upregulation of TaAG-B was observed in the CMS line. The transcript levels of the two genes were clearly higher in the CMS line compared to the maintainer line at the trinucleate stage. Overexpression of TaAG-A and TaAG-B in Arabidopsis resulted in phenotypes with earlier reproductive development, premature mortality, and abnormal buds, stamens, and stigmas. Overexpression of TaAG-A and TaAG-B gives rise to mutants with many deformities. Silencing TaAG-A and TaAG-B in a fertile wheat line using the virus-induced gene silencing (VIGS method resulted in plants with green and yellow striped leaves, emaciated spikes, and decreased selfing seed set rates. These results demonstrate that TaAG-A and TaAG-B may play a role in male sterility in the wheat CMS line.

  13. ESR dating of laterite from Ban Tha Ta Suea, Kanchanaburi, Thailand

    International Nuclear Information System (INIS)

    Limsuwan, S.; Vichaidid, T.; Limsuwan, P.

    2011-01-01

    Electron spin resonance (ESR) dating was carried out on laterite samples collected from Ban Tha Ta Suea, the original deposit of the laterite used in the construction of Muang Sing Historical Park. Ban Tha Ta Suea is about 6 km east of Muang Sing Historical Park in Kanchanaburi province (181 km far from Bangkok). The dose response of the g=2.0028 ESR signal was found to be suitable for age determination. An exponential saturation function was fitted to the ESR signal growth on additional γ-irradiation. Extrapolation of this function resulted in the accumulated dose 144±5 Gy. Gamma spectroscopy and neutron activation analysis (NAA) were used to determine concentrations of 238 U, 232 Th and 40 K in the samples from which the annual dose rate 16±2 mGy was calculated. In addition, the dose rate of cosmic rays was taken into account. The ESR age of laterite samples was found to be 9.0±0.9 ka. This age falls within the Holocene epoch of the Quaternary on the geological time scale. Samples from Muang Sing Historical Park were assigned to the same epoch. Both results agree with the geological map.

  14. EDITORIAL: TaCoNa-Photonics 2008 TaCoNa-Photonics 2008

    Science.gov (United States)

    Chigrin, Dmitry N.; Busch, Kurt; Lavrinenko, Andrei V.

    2009-11-01

    This special section on theoretical and computational nano-photonics features papers presented at the first International Workshop on Theoretical and Computational Nano-Photonics (TaCoNa-Photonics 2008) held in Bad Honnef, Germany, 3-5 December 2008. The workshop covered a broad range of topics related to current developments and achievements in this interdisciplinary area of research. Since the late 1960s, the word `photonics' has been understood as the science of generating, controlling, and detecting light. Nowadays, a routine fabrication of complex structures with micro- and nano-scale dimensions opens up many new and exciting possibilities in photonics. The science of generating, routing and detecting light in micro- and nano-structured matter, `nano-photonics', is becoming more important both in research and technology and offers many promising applications. The inherently sub-wavelength character of the structures that nano-photonics deals with challenges modern theoretical and computational physics and engineering with many nontrivial questions: Up to what length-scale can one use a macroscopic phenomenological description of matter? Where is the interface between the classical and quantum description of light in nano-scale structures? How can one combine different physical systems, different time- and length-scales in a single computational model? How can one engineer nano-structured materials in order to achieve the desired optical properties for particular applications? Any attempt at answering these kinds of questions is impossible without the joint efforts of physicists, engineers, applied mathematicians and programmers. This is the reason why the major goal of the TaCoNa-Photonics workshops is to provide a forum where theoreticians and specialists in numerical methods from all branches of physics, engineering sciences and mathematics can compare their results, report on novel results and breakthroughs, and discuss new challenges ahead. In order to

  15. Analysis of phase formation in Ni-rich alloys of the Ni-Ta-W system by calorimetry, DTA, SEM, and TEM

    Energy Technology Data Exchange (ETDEWEB)

    Witusiewicz, V.T.; Hecht, U.; Warnken, N.; Fries, S.G. [Access e.V., Aachen (Germany); Hu Weiping [Inst. fuer Metallkunde und Metallphysik der RWTH Aachen (Germany)

    2006-04-15

    The partial enthalpies of dissolution of pure Ni, W and Ta in liquid ternary Ni-Ta-W alloys have been determined at (1773 {+-} 5) K using a high temperature isoperibolic calorimeter. Measurements were performed in Ni-rich alloys (from 80 to 100 at.% Ni) along sections with constant Ta:W atomic ratios 1:0, 2:1, 1:2, and 0:1. The partial enthalpies and thereby the integral enthalpy of mixing of these ternary alloys are calculated from the partial enthalpies of dissolution using SGTE Gibbs energies for pure elements as reference. The obtained thermochemical data confirm that in the investigated Ni-rich alloys the binary interactions between Ta and W as well as the ternary Ni-Ta-W interactions are negligibly small. Due to this the variation of the integral enthalpy of mixing of the ternary alloys is well described as linear combination of the constituent Ni-Ta and Ni-W binaries. Such behaviour of the ternary liquid alloys is related to a very low probability of new ternary stable phases to occur in solid state. This prediction is confirmed by differential thermal analysis, scanning electron microscopy, and transmission electron microscopy of the as-solidified and annealed samples obtained as last alloy compositions in the series of calorimetric dissolution. (orig.)

  16. Effects of Y incorporation in TaON gate dielectric on electrical performance of GaAs metal-oxide-semiconductor capacitor

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Li Ning; Choi, Hoi Wai; Lai, Pui To [Department of Electrical and Electronic Engineering, The University of Hong Kong (China); Xu, Jing Ping [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan (China)

    2016-09-15

    In this study, GaAs metal-oxide-semiconductor (MOS) capacitors using Y-incorporated TaON as gate dielectric have been investigated. Experimental results show that the sample with a Y/(Y + Ta) atomic ratio of 27.6% exhibits the best device characteristics: high k value (22.9), low interfacestate density (9.0 x 10{sup 11} cm{sup -2} eV{sup -1}), small flatband voltage (1.05 V), small frequency dispersion and low gate leakage current (1.3 x 10{sup -5}A/cm{sup 2} at V{sub fb} + 1 V). These merits should be attributed to the complementary properties of Y{sub 2}O{sub 3} and Ta{sub 2}O{sub 5}:Y can effectively passivate the large amount of oxygen vacancies in Ta{sub 2}O{sub 5}, while the positively-charged oxygen vacancies in Ta{sub 2}O{sub 5} are capable of neutralizing the effects of the negative oxide charges in Y{sub 2}O{sub 3}. This work demonstrates that an appropriate doping of Y content in TaON gate dielectric can effectively improve the electrical performance for GaAs MOS devices. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Long periodicity of Blazar with RXTE ASM, TA and HEGRA

    OpenAIRE

    Osone, S.; Teshima, M.

    2002-01-01

    Long periodicity for Mkn501 during a large flare in 1997 have been reported by TA, HEGRA group. Here, we establish this periodicity with archival data of RXTE All Sky Monitor(ASM), Telescope Array(TA) and HEGRA with a chance probability less than $10^{-5}$. We also find that an origin of 23 day periodicity is related with a change of either a gamma factor of electrons $\\gamma$ or the magnetic field or a beaming factor. And, in order to search for a category which have a long periodicity, we m...

  18. Nd:Ta2O5 rib waveguide lasers

    International Nuclear Information System (INIS)

    Unal, Bayram; Tai, C.-Y.; Shepherd, David P.; Wilkinson, James S.; Perney, Nicolas M.B.; Netti, M. Caterina; Parker, Gregory J.

    2005-01-01

    Ta 2 O 5 waveguides offer great potential for high-density active photonic crystal circuits and their combination with rare-earth dopants for active devices is of interest for increasing their potential functionality. To this end, neodymium-doped Ta 2 O 5 rib waveguide lasers have been fabricated on an oxidized silicon wafer by rf sputtering and argon ion-beam milling and laser action in this material has been demonstrated. Lasing was observed at wavelenghts between 1060 and 1080 nm and an absorbed pump power threshold of 87 mW was obtained

  19. Ar-Ar dating and petrogenesis of the Early Miocene Taşkapı-Mecitli (Erciş-Van) granitoid, Eastern Anatolia Collisional Zone, Turkey

    Science.gov (United States)

    Oyan, Vural

    2018-06-01

    The Early Miocene Taşkapı-Mecitli granitoid that is located in the northern section of the Eastern Anatolia Collision Zone has typical I-type, metaluminous and calk-alkaline characteristics. It also contains mafic microgranular / magmatic enclaves (MMEs). New Ar-Ar dating results show that the age of the Taşkapı-Mecitli granitoid is ∼23 Ma and it crystallised in the Early Miocene, in contrast to its previously known Cretaceous age. Identical crystallisation ages (∼23 Ma), similar mineral assemblages and geochemical compositions, and indistinguishable isotopic compositions of MMEs and host rocks imply that the MMEs are most consistent with a cumulate origin formed at earlier stages of the same magmatic system that produced the Taşkapı-Mecitli granitoid. MELTS modelling suggests that magma of the Taşkapı-Mecitli granitoid was the result of fractionation under a crustal pressure of 4 kbar, with a H2O content of 1.5%. EC-AFC model calculation reveals that the Taşkapı-Mecitli granitoid includes from 0.5% to 2% crustal assimilation rates. These rates indicate that crustal contamination can be negligible when compared to fractional crystallisation in the evolution of the magma beneath the Taşkapı-Mecitli granitoid. The partial melting model calculations and MORB-normalised trace element concentrations of the least evolved samples of the Taşkapı-Mecitli granitoid are consistent with those of mafic melts obtained from partial melting of interacting mantle- lower crust with a melting degree of 18%. The age (23 Ma) of the post- or syn-collisional Taşkapı-Mecitli granitoid suggests that the collision between Arabian and Eurasian plates could be before/around ∼23 Ma (Late Oligocene to Early Miocene).

  20. Superstructure Ta2O5 mesocrystals derived from (NH4)2Ta2O3F6 mesocrystals with efficient photocatalytic activity.

    Science.gov (United States)

    Yu, Xin; Li, Wei; Huang, Jian; Li, Zhonghua; Liu, Jiawen; Hu, PingAn

    2018-02-06

    Superstructured mesocrystalline Ta 2 O 5 nanosheets were successfully prepared from mesocrystalline (NH 4 ) 2 Ta 2 O 3 F 6 nanorods by the annealing method for the first time. The as-prepared mesocrystalline Ta 2 O 5 nanosheets in this work showed remarkable visible light absorption, mainly due to the formation of oxygen vacancy defects in the mesocrystalline Ta 2 O 5 nanosheets, which was also confirmed by XPS spectra, Raman spectra and EPR spectra. Besides, the mesocrystalline Ta 2 O 5 nanosheets showed a highly enhanced photocatalytic activity of 11 268.24 μmol g -1 h -1 , about 3.95 times that of commercial Ta 2 O 5 . Moreover, the specific surface area of the mesocrystalline Ta 2 O 5 -800 nanosheets was 16.34 m 2 g -1 , about 5.32 times that of the commercial Ta 2 O 5 (3.072 m 2 g -1 ). The valence band XPS spectra indicated a strong oxidizing ability of the mesocrystalline Ta 2 O 5 nanosheets in comparison to that of commercial Ta 2 O 5 . The formation of superstructured Ta 2 O 5 mesocrystals generated long lifetime carriers and effective conduction pathways, which greatly enhanced the photocatalytic activity for hydrogen production.

  1. Petrochemical Characteristics and Age of Rare Metal (Ta-Nb Mineralization in Precambrian Pegmatites, Komu, Nigeria

    Directory of Open Access Journals (Sweden)

    A. OLUGBENGA

    2010-06-01

    Full Text Available The Precambrian pegmatites of Komu area intrude semi discordantly older rock types, such as biotite gneiss, amphibolites and pelitic schists. The pegmatites occur as near flat lying bodies. This study aims at elucidating the geological setting, petrography, geochemical features and age of mineralization of these pegmatite bodies, with a view to classifying them and knowing their economic potential. The petrographic analysis shows that the pegmatite samples contain mainly quartz (35%, plagioclase (15%, microcline (10% and muscovite (12% with accessories like tourmaline, tantalum, niobium and illmeno-rutiles. Geochemical analysis of the muscovites extracted from pegmatites show that these rocks are enriched in silica (>60% and Al2O3 (>12% and depleted in Fe2O3, MgO and TiO2. Trace element analysis shows that the pegmatites contain rare metals with moderately high Ta, Nb, Sn, Rb, Li and Cs values and depleted in Ti, Ba and Zr. Elemental ratios indicate low ratios of K/Cs, Th/U and K/Rb. Variation plots of Ta/(Ta+Nb versus Mn/ (Mn+Fe show that the pegmatites plot in the complex (beryl subtype field. The Na/K versus Sn, Nb, Rb variation plots show that the pegmatites of Komu area are mineralized and compare favourably with those of other mineralized pegma-tite areas like Egbe and Ijero in southwestern Nigeria. The variation plots of Ta versus K/Cs, and Ta/W versus Cs, also confirm rare metal mineralization of Komu pegmatites, which plot over the mineralized line of Beus and Gordiyenko. The K/Rb versus Rb, Cs and Sn plots indicate low K/Rb ratios indicating moderate differentiation. The Rare Earth Elements (REE show high heavy REE values and lower light REE values with prominent positive Ce anomaly and negative Eu anomaly from normalized chondrite plots. K/Ar dating of the age of mineralization of muscovites extracted from the pegmatite yielded late Pan-African ages between 502.8±13Ma and 514.5±13.2Ma. This period represents the cooling ages of the

  2. Mutagenic activity of 2-(2',4'-diaminophenoxy)ethanol in strains TA1538 and TA98 of Salmonella typhimurium.

    Science.gov (United States)

    Mohn, G; Bouter, S; de Knijff, P

    1982-12-01

    The mutagenicity of 2-(2',4'-diaminophenoxy)ethanol (2,4-DAPE) was compared with that of 2,4-diaminoanisole (2,4-DAA), a chemically related compound previously used in hair-dye formulations. Both chemicals were tested in standard procedures with the Salmonella/microsome mutagenicity test as described by Ames and colleagues. In several experiments, which extended over a total period of 2 years, 2,4-DAA exhibited definite, but variable mutagenicity toward strain TA1538 when S9 preparations of rat liver induced with Aroclor 1254 were present in the incubation mixtures. The compound 2,4-DAPE did not exhibit detectable mutagenic activity when tested concomitantly under the same experimental conditions. We conclude that 2,4-DAPE is not mutagenic for Salmonella under conditions of the standard mammalian microsome assay with strain TA1538 and TA98 as indicators.

  3. Phase relationships in the BaO-Ga2O3-Ta2O5 system and the structure of Ba6Ga21TaO40.

    Science.gov (United States)

    Cao, Jiang; Yu, Xiaodi; Kuang, Xiaojun; Su, Qiang

    2012-07-16

    Phase relationships in the BaO-Ga(2)O(3)-Ta(2)O(5) ternary system at 1200 °C were determined. The A(6)B(10)O(30) tetragonal tungsten bronze (TTB) related solution in the BaO-Ta(2)O(5) subsystem dissolved up to ~11 mol % Ga(2)O(3), forming a ternary trapezoid-shaped TTB-related solid solution region defined by the BaTa(2)O(6), Ba(1.1)Ta(5)O(13.6), Ba(1.58)Ga(0.92)Ta(4.08)O(13.16), and Ba(6)GaTa(9)O(30) compositions in the BaO-Ga(2)O(3)-Ta(2)O(5) system. Two ternary phases Ba(6)Ga(21)TaO(40) and eight-layer twinned hexagonal perovskite solid solution Ba(8)Ga(4-x)Ta(4+0.6x)O(24) were confirmed in the BaO-Ga(2)O(3)-Ta(2)O(5) system. Ba(6)Ga(21)TaO(40) crystallized in a monoclinic cell of a = 15.9130(2) Å, b = 11.7309(1) Å, c = 5.13593(6) Å, β = 107.7893(9)°, and Z = 1 in space group C2/m. The structure of Ba(6)Ga(21)TaO(40) was solved by the charge flipping method, and it represents a three-dimensional (3D) mixed GaO(4) tetrahedral and GaO(6)/TaO(6) octahedral framework, forming mixed 1D 5/6-fold tunnels that accommodate the Ba cations along the c axis. The electrical property of Ba(6)Ga(21)TaO(40) was characterized by using ac impedance spectroscopy.

  4. Sintering and characterization of SrBi_2Ta_2O_9 obtained by high-pressure processing at low temperatures

    International Nuclear Information System (INIS)

    Souza, Ricson R.; Kirchner, Rejane K.; Jurado, Jose R.; Pereira, Altair S.; Sousa, Vânia C.

    2016-01-01

    High-pressure processing is a very attractive approach for the production of materials with new and/or improved properties. In this work, pressures in the order of 7.7 GPa and 2.5 GPa were induced in SrBi_2Ta_2O_9 samples at different temperatures placed in a specific reaction cell and generated different effects on phase formation. The microstructural evolution during high-pressure processing was investigated by scanning electron microscopy in association with energy dispersion spectroscopy and with the support of an X-ray diffraction analyzer. Frequency response analysis was used to obtain the dielectric curves by electrochemical impedance spectroscopy. A SrBi_2Ta_2O_9 single-phase sample, treated at 2.5 GPa and 900 °C, was used to evaluate the electrical properties, obtaining a dielectric response similar to SrBi_2Ta_2O_9 samples sintered by conventional processes at temperatures above 1000 °C. In addition, by this method, it was possible to obtain ceramics with uniform microstructure and a relative density of 93%. - Highlights: • The first production of SrBi_2Ta_2O_9 using the technique of high-pressure processing. • The ability to produce single-phase SrBi_2Ta_2O_9 treated at 2.5 GPa and 900 °C. • The electrical properties are compatible with SBT sintered at high temperatures.

  5. Synthesis and magnetic properties of Ta/NdFeB-based composite microwires

    Energy Technology Data Exchange (ETDEWEB)

    Szary, P., E-mail: philipp.szary@uni.lu; Périgo, E. A.; Michels, A. [Physics and Materials Science Research Unit, University of Luxembourg, 162 Avenue de la Faïencerie, L-1511 Luxembourg, Grand Duchy of Luxembourg (Luxembourg); Luciu, I.; Duday, D.; Wirtz, T.; Choquet, P. [Science and Analysis of Materials (SAM), Centre de Recherche Public—Gabriel Lippmann, 41, rue du Brill, L-4422 Belvaux, Grand Duchy of Luxembourg (Luxembourg)

    2015-05-07

    Magnetic NdFeB-based microwire composites have been prepared by the direct current magnetron sputtering technique in a specifically designed sputtering chamber for thin-film deposition in wire geometry. As substrate wire material, we have employed steel and Ta. Annealing of the substrate wires during the deposition process was performed by ohmic heating through the application of a direct current. Samples were characterized by means of vibrating sample magnetometry (VSM) and scanning electron microscopy. Best properties have been encountered when using Ta wires as core (substrate) material. The VSM data show a dramatic impact of the current applied during the deposition process on the magnetic properties. For higher current values, i.e., higher annealing temperatures, the wires exhibit a reversal process that is typical for a two-phase system. Moreover, an increase of the coercive field (and remanent magnetization) is observed, which is ascribed to a modification of the magnetic phase present in the sample due to the annealing. We find an indication for the formation of a magnetic easy-axis direction which is azimuthally oriented around the wire axis.

  6. Charge trapping of Ge-nanocrystals embedded in TaZrO{sub x} dielectric films

    Energy Technology Data Exchange (ETDEWEB)

    Lehninger, D., E-mail: David.Lehninger@physik.tu-freiberg.de; Seidel, P.; Geyer, M.; Schneider, F.; Heitmann, J. [Institute of Applied Physics, TU Bergakademie Freiberg, D-09596 Freiberg (Germany); Klemm, V.; Rafaja, D. [Institute of Materials Science, TU Bergakademie Freiberg, D-09596 Freiberg (Germany); Borany, J. von [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, D-01314 Dresden (Germany)

    2015-01-12

    Ge-nanocrystals (NCs) were synthesized in amorphous TaZrO{sub x} by thermal annealing of co-sputtered Ge-TaZrO{sub x} layers. Formation of spherical shaped Ge-NCs with small variation of size, areal density, and depth distribution was confirmed by high-resolution transmission electron microscopy. The charge storage characteristics of the Ge-NCs were investigated by capacitance-voltage and constant-capacity measurements using metal-insulator-semiconductor structures. Samples with Ge-NCs exhibit a maximum memory window of 5 V by sweeping the bias voltage from −7 V to 7 V and back. Below this maximum, the width of the memory window can be controlled by the bias voltage. The fitted slope of the memory window versus bias voltage characteristics is very close to 1 for samples with one layer Ge-NCs. A second layer Ge-NCs does not result in a second flat stair in the memory window characteristics. Constant-capacity measurements indicate charge storage in trapping centers at the interfaces between the Ge-NCs and the surrounding materials (amorphous matrix/tunneling oxide). Charge loss occurs by thermal detrapping and subsequent band-to-band tunneling. Reference samples without Ge-NCs do not show any memory window.

  7. Charge trapping of Ge-nanocrystals embedded in TaZrOx dielectric films

    International Nuclear Information System (INIS)

    Lehninger, D.; Seidel, P.; Geyer, M.; Schneider, F.; Heitmann, J.; Klemm, V.; Rafaja, D.; Borany, J. von

    2015-01-01

    Ge-nanocrystals (NCs) were synthesized in amorphous TaZrO x by thermal annealing of co-sputtered Ge-TaZrO x layers. Formation of spherical shaped Ge-NCs with small variation of size, areal density, and depth distribution was confirmed by high-resolution transmission electron microscopy. The charge storage characteristics of the Ge-NCs were investigated by capacitance-voltage and constant-capacity measurements using metal-insulator-semiconductor structures. Samples with Ge-NCs exhibit a maximum memory window of 5 V by sweeping the bias voltage from −7 V to 7 V and back. Below this maximum, the width of the memory window can be controlled by the bias voltage. The fitted slope of the memory window versus bias voltage characteristics is very close to 1 for samples with one layer Ge-NCs. A second layer Ge-NCs does not result in a second flat stair in the memory window characteristics. Constant-capacity measurements indicate charge storage in trapping centers at the interfaces between the Ge-NCs and the surrounding materials (amorphous matrix/tunneling oxide). Charge loss occurs by thermal detrapping and subsequent band-to-band tunneling. Reference samples without Ge-NCs do not show any memory window

  8. Safety analysis of the main vault at TA-41, LASL

    International Nuclear Information System (INIS)

    Ehrenkranz, T.E.; Dahl, D.A.; Plassmann, E.H.; Pogna, R.; Smith, D.R.

    1978-02-01

    Safety considerations discussed in this report show that special nuclear materials stored at a Los Alamos Scientific Laboratory facility (TA-41) present no inappropriate risk to workers or the public. The report addresses nuclear criticality, fire, and radioactive contamination potentials, as well as physical protection and material safeguards

  9. Generation of Ta ions at high laser-power densities

    Czech Academy of Sciences Publication Activity Database

    Láska, Leoš; Jungwirth, Karel; Králiková, Božena; Krása, Josef; Pfeifer, Miroslav; Rohlena, Karel; Skála, Jiří; Ullschmied, Jiří; Badziak, J.; Parys, P.; Wolowski, J.; Woryna, E.

    2002-01-01

    Roč. 52, Suppl. D (2002), s. D283-D291 ISSN 0011-4626. [Plasma Physics and Technology. Prague, 10.06.2002-13.06.2002] Institutional research plan: CEZ:AV0Z1010921 Keywords : laser produced plasma * multiple charged Ta ions Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.311, year: 2002

  10. Superconducting state in (W, Ta)5SiB2

    Science.gov (United States)

    Fukuma, M.; Kawashima, K.; Akimitsu, J.

    We characterize the superconducting state in a boro-silicide (W, Ta)5SiB2, with Tc of 6.5 K by means of magnetization, electrical resistivity, and specific heat measurements. As x increased, the transition temperature Tc abruptly enhances from 5.8 to 6.5 K. The magnetization versus magnetic field (M-H) curve indicated that (W, Ta)5SiB2 was a conventional type-II superconductor. The estimated lower critical field Hc1(0) and upper critical field Hc2(T) are about 121 Oe and 14.7 kOe, respectively. The penetration depth λ(0) and coherence length ξ(0) are calculated to be approximately 369 and 14.9 nm, respectively, using Ginzburg-Landau (GL) equations. Specific heat data shows the superconductivity in W4.5Ta0.5SiB2 belongs to a week-coupling BCS superconductor. Finally, we discuss the increasing of Tc in of (W, Ta)5SiB2 system.

  11. Recoil range distribution measurement in 20Ne + 181Ta reaction

    International Nuclear Information System (INIS)

    Tripathi, R.; Sudarshan, K.; Goswami, A.; Guin, R.; Reddy, A.V.R.

    2005-01-01

    In order to investigate linear momentum transfer in various transfer channels in 20 Ne + 181 Ta, recoil range distribution measurements have been carried out at E lab = 180 MeV, populating significant number of l-waves above l crit

  12. Ingreso de psittacidos al centro de atención de fauna (CAV–CVS, durante los años 2007-2009

    Directory of Open Access Journals (Sweden)

    Juan Carrascal V.

    2013-03-01

    Full Text Available Objetivo. En este estudio se determinó la dinámica de ingresos de la familia Psittacidae al Centro de Atención y Valoración de Fauna Silvestre (CAV – CVS. Materiales y métodos. Se tomaron datos obtenidos desde el año 2007 hasta el año 2009, a los cuales se implementó análisis de frecuencias para las variables especies, tipo de ingreso y tiempo (meses y años, para la variable meses se aplicó un análisis de diferencia de medias y se presentó la relación ingreso de las especies versus los meses del año, por medio de un stripplot. Resultados. La familia Psittacidae presentó el 58% del total de aves que ingresaron al CAV producto de decomisos preventivos realizados en mercados públicos y vías del departamento de Córdoba. La especie con mayor frecuencia de ingresos fue Brotogeris jugularis, con 73.99% del total de individuos, siendo la especie que obtuvo los mayores ingresos durante todo el año. Asimismo, se encontró diferencias significativas para el ingreso por meses (X2= 26.785, gl = 11, p-valor = 0.004951. Conclusiones. Se logró determinar que la época seca, acorde con las festividades en el departamento, presentó los valores más altos de ingresos.

  13. Direct somatic embryogenesis in coffea arabica L. CVS. caturra and catuaí: effect of triacontanol, light condition, and medium consistency

    Directory of Open Access Journals (Sweden)

    Andrés M. Gatica

    2008-01-01

    Full Text Available Se investigó la influencia de la concentración de triacontanol (TRIA y su interacción con el ácido indolacético (AIA en la inducción de la embriogénesis somática directa en Coffea arabica L. cvs. Caturra y Catuaí. Adicionalmente, se evaluó el efecto de la condición de la luz y de la consistencia del medio de cultivo (semisólido vs. líquido. Se determinó que la mayor cantidad de embriones somáticos por explante fue de 3,9±0,5 en Caturra y 3,6±0,5 en Catuaí, en el medio de cultivo Murashige y Skoog (1962 al 50%, complementado con BAP (1,1 µM, IAA (2,85 µM y TRIA (4,55 µM. Para la consistencia del medio, la mayor cantidad de embriones somáticos en Caturra (3,2±0,2 y Catuaí (6,0±0,4 se obtuvo con el medio semisólido de Yasuda et al. (1985. En Catuaí, la mayor cantidad de embrioides se obtuvo con 16 h luz (7,6±1,0 y oscuridad (6,2±0,6 y para Caturra, con oscuridad (4,2±0,4 y 16 h luz (3,8±0,5. No se observó la formación de embriones somáticos en los explantes de Caturra y Catuaí después de 12 semanas de cultivo, en el medio líquido descrito por Yasuda et al. (1985 ni bajo ninguna de las condiciones de luz.

  14. Xanthine oxidase functionalized Ta2O5 nanostructures as a novel scaffold for highly sensitive SPR based fiber optic xanthine sensor.

    Science.gov (United States)

    Kant, Ravi; Tabassum, Rana; Gupta, Banshi D

    2018-01-15

    Fabrication and characterization of a surface plasmon resonance based fiber optic xanthine sensor using entrapment of xanthine oxidase (XO) enzyme in several nanostructures of tantalum (v) oxide (Ta 2 O 5 ) have been reported. Chemical route was adopted for synthesizing Ta 2 O 5 nanoparticles, nanorods, nanotubes and nanowires while Ta 2 O 5 nanofibers were prepared by electrospinning technique. The synthesized Ta 2 O 5 nanostructures were characterized by photoluminescence, scanning electron microscopy, UV-Visible spectra and X-ray diffraction pattern. The probes were fabricated by coating an unclad core of the fiber with silver layer followed by the deposition of XO entrapped Ta 2 O 5 nanostructures. The crux of sensing mechanism relies on the modification of dielectric function of sensing layer upon exposure to xanthine solution of diverse concentrations, reflected in terms of shift in resonance wavelength. The sensing probe coated with XO entrapped Ta 2 O 5 nanofibers has been turned out to possess maximum sensitivity amongst the synthesized nanostructures. The probe was optimized in terms of pH of the sample and the concentration of XO entrapped in Ta 2 O 5 nanofibers. The optimized sensing probe possesses a remarkably good sensitivity of 26.2nm/µM in addition to linear range from 0 to 3µM with an invincible LOD value of 0.0127µM together with a response time of 1min. Furthermore, probe selectivity with real sample analysis ensure the usage of the sensor for practical scenario. The results reported open a novel perspective towards a sensitive, rapid, reliable and selective detection of xanthine. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Investigation of the phase formation and dielectric properties of Bi{sub 7}Ta{sub 3}O{sub 18}

    Energy Technology Data Exchange (ETDEWEB)

    Chon, M.P. [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Tan, K.B., E-mail: tankb@science.upm.my [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Khaw, C.C. [Department of Mechanical and Material Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, 53300 Setapak, Kuala Lumpur (Malaysia); Zainal, Z.; Taufiq Yap, Y.H. [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Chen, S.K. [Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Tan, P.Y. [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia)

    2014-03-25

    Highlights: • Synthesis condition of Bi{sub 7}TaO{sub 3}O{sub 18} had been determined. • Recombination of intermediate BiTaO{sub 4} and Bi{sub 3}TaO{sub 7} phases are required for the Bi{sub 7}TaO{sub 3}O{sub 18} phase formation. • Stable material as confirmed by thermal and structural analyses. • Typical ferroelectric showing high dielectric constants and low losses. • Resonance and thermal activated polarisation processes are responsible for the excellent dielectric characteristic. -- Abstract: Polycrystalline Bi{sub 7}Ta{sub 3}O{sub 18} was synthesised at the firing temperature of 950 °C over 18 h via conventional solid state method. It crystallised in a monoclinic system with space group C2/m, Z = 4 similar to that reported diffraction pattern in the Inorganic Crystal Structure Database (ICSD), 1-89-6647. The refined lattice parameters were a = 34.060 (3) Å, b = 7.618 (9) Å, c = 6.647 (6) Å with α = γ = 90° and β = 109.210 (7), respectively. The intermediate phase was predominantly in high-symmetry cubic structure below 800 °C and finally evolved into a low-symmetry monoclinic structured, Bi{sub 7}Ta{sub 3}O{sub 18} at 950 °C. The sample contained grains of various shapes with different orientations in the size ranging from 0.33–22.70 μm. The elemental analysis showed the sample had correct stoichiometry with negligible Bi{sub 2}O{sub 3} loss. Bi{sub 7}Ta{sub 3}O{sub 18} was thermally stable and it exhibited a relatively high relative permittivity, 241 and low dielectric loss, 0.004 at room temperature, ∼30 °C and frequency of 1 MHz.

  16. Studies on layer growth and interfaces on Ta-base thin layers by means of XPS; Untersuchungen zu Schichtwachstum und Grenzflaechen an Ta-basierten Duennschichten mittels XPS

    Energy Technology Data Exchange (ETDEWEB)

    Zier, M.

    2007-11-02

    In this thesis studies on the growth and on the formation of the interfaces of Ta and TaN layers on Si and SiO{sub 2} were performed. In the system TaN on SiO{sub 2} no reaction on the interface could be found. As the system with the mostly disturbed interface Ta on SiO{sub 2} was proved. Here a reduction of the SiO{sub 2} at simultaneous oxidation of the Ta was to be observed. Additionally tantalum silicide was formed to be considered concerning the bonding state as Ta{sub 5}Si{sub 3}, from which a double layer of a tantalum silicide and a tantalum suboxide resulted. A whole thickness of the double layer of above 1 nm resulted. In the system Ta on Si at the deposition of the film on the interface a tantalum silicide was formed to be characterized concerning the bonding state as TaSi{sub 2}. The thickness of the interlayer growed thereby up to 0.8 nm in form of islands. Finally in the system TaN on Si a silicon nitride formation during the deposition was observed, which was attributed to the insertion of adsorbed nitrogen from the sputtering atmosphere by recoil implantation of the sputtered Ta atoms. The silicon nitride interlayer growed thereby up to a thickness of 0.8 nm.

  17. Drought-responsive WRKY transcription factor genes TaWRKY1 and TaWRKY33 from wheat confer drought and/or heat resistance in Arabidopsis.

    Science.gov (United States)

    He, Guan-Hua; Xu, Ji-Yuan; Wang, Yan-Xia; Liu, Jia-Ming; Li, Pan-Song; Chen, Ming; Ma, You-Zhi; Xu, Zhao-Shi

    2016-05-23

    Drought stress is one of the major causes of crop loss. WRKY transcription factors, as one of the largest transcription factor families, play important roles in regulation of many plant processes, including drought stress response. However, far less information is available on drought-responsive WRKY genes in wheat (Triticum aestivum L.), one of the three staple food crops. Forty eight putative drought-induced WRKY genes were identified from a comparison between de novo transcriptome sequencing data of wheat without or with drought treatment. TaWRKY1 and TaWRKY33 from WRKY Groups III and II, respectively, were selected for further investigation. Subcellular localization assays revealed that TaWRKY1 and TaWRKY33 were localized in the nuclei in wheat mesophyll protoplasts. Various abiotic stress-related cis-acting elements were observed in the promoters of TaWRKY1 and TaWRKY33. Quantitative real-time PCR (qRT-PCR) analysis showed that TaWRKY1 was slightly up-regulated by high-temperature and abscisic acid (ABA), and down-regulated by low-temperature. TaWRKY33 was involved in high responses to high-temperature, low-temperature, ABA and jasmonic acid methylester (MeJA). Overexpression of TaWRKY1 and TaWRKY33 activated several stress-related downstream genes, increased germination rates, and promoted root growth in Arabidopsis under various stresses. TaWRKY33 transgenic Arabidopsis lines showed lower rates of water loss than TaWRKY1 transgenic Arabidopsis lines and wild type plants during dehydration. Most importantly, TaWRKY33 transgenic lines exhibited enhanced tolerance to heat stress. The functional roles highlight the importance of WRKYs in stress response.

  18. The Wheat Mediator Subunit TaMED25 Interacts with the Transcription Factor TaEIL1 to Negatively Regulate Disease Resistance against Powdery Mildew1

    Science.gov (United States)

    Zhang, Tianren; Jia, Jizeng; Sun, Jiaqiang

    2016-01-01

    Powdery mildew, caused by the biotrophic fungal pathogen Blumeria graminis f. sp. tritici, is a major limitation for the production of bread wheat (Triticum aestivum). However, to date, the transcriptional regulation of bread wheat defense against powdery mildew remains largely unknown. Here, we report the function and molecular mechanism of the bread wheat Mediator subunit 25 (TaMED25) in regulating the bread wheat immune response signaling pathway. Three homoalleles of TaMED25 from bread wheat were identified and mapped to chromosomes 5A, 5B, and 5D, respectively. We show that knockdown of TaMED25 by barley stripe mosaic virus-induced gene silencing reduced bread wheat susceptibility to the powdery mildew fungus during the compatible plant-pathogen interaction. Moreover, our results indicate that MED25 may play a conserved role in regulating bread wheat and barley (Hordeum vulgare) susceptibility to powdery mildew. Similarly, bread wheat ETHYLENE INSENSITIVE3-LIKE1 (TaEIL1), an ortholog of Arabidopsis (Arabidopsis thaliana) ETHYLENE INSENSITIVE3, negatively regulates bread wheat resistance against powdery mildew. Using various approaches, we demonstrate that the conserved activator-interacting domain of TaMED25 interacts physically with the separate amino- and carboxyl-terminal regions of TaEIL1, contributing to the transcriptional activation activity of TaEIL1. Furthermore, we show that TaMED25 and TaEIL1 synergistically activate ETHYLENE RESPONSE FACTOR1 (TaERF1) transcription to modulate bread wheat basal disease resistance to B. graminis f. sp. tritici by repressing the expression of pathogenesis-related genes and deterring the accumulation of reactive oxygen species. Collectively, we identify the TaMED25-TaEIL1-TaERF1 signaling module as a negative regulator of bread wheat resistance to powdery mildew. PMID:26813794

  19. The Wheat Mediator Subunit TaMED25 Interacts with the Transcription Factor TaEIL1 to Negatively Regulate Disease Resistance against Powdery Mildew.

    Science.gov (United States)

    Liu, Jie; Zhang, Tianren; Jia, Jizeng; Sun, Jiaqiang

    2016-03-01

    Powdery mildew, caused by the biotrophic fungal pathogen Blumeria graminis f. sp. tritici, is a major limitation for the production of bread wheat (Triticum aestivum). However, to date, the transcriptional regulation of bread wheat defense against powdery mildew remains largely unknown. Here, we report the function and molecular mechanism of the bread wheat Mediator subunit 25 (TaMED25) in regulating the bread wheat immune response signaling pathway. Three homoalleles of TaMED25 from bread wheat were identified and mapped to chromosomes 5A, 5B, and 5D, respectively. We show that knockdown of TaMED25 by barley stripe mosaic virus-induced gene silencing reduced bread wheat susceptibility to the powdery mildew fungus during the compatible plant-pathogen interaction. Moreover, our results indicate that MED25 may play a conserved role in regulating bread wheat and barley (Hordeum vulgare) susceptibility to powdery mildew. Similarly, bread wheat ETHYLENE INSENSITIVE3-LIKE1 (TaEIL1), an ortholog of Arabidopsis (Arabidopsis thaliana) ETHYLENE INSENSITIVE3, negatively regulates bread wheat resistance against powdery mildew. Using various approaches, we demonstrate that the conserved activator-interacting domain of TaMED25 interacts physically with the separate amino- and carboxyl-terminal regions of TaEIL1, contributing to the transcriptional activation activity of TaEIL1. Furthermore, we show that TaMED25 and TaEIL1 synergistically activate ETHYLENE RESPONSE FACTOR1 (TaERF1) transcription to modulate bread wheat basal disease resistance to B. graminis f. sp. tritici by repressing the expression of pathogenesis-related genes and deterring the accumulation of reactive oxygen species. Collectively, we identify the TaMED25-TaEIL1-TaERF1 signaling module as a negative regulator of bread wheat resistance to powdery mildew. © 2016 American Society of Plant Biologists. All Rights Reserved.

  20. Creep rupture properties of laves phase strengthened Fe--Ta--Cr--W and Fe--Ta--Cr--W--Mo alloys

    International Nuclear Information System (INIS)

    Singh, S.

    1975-12-01

    A small addition of tungsten (0.5 at. percent) was shown to have an effect similar to that of molybdenum on the phase transformation characteristics of alloy Ta7Cr (with a nominal composition of 1 at. percent Ta, 7 at. percent Cr, balance Fe). The existence of time-temperature dependent transformation behavior in alloy Ta7Cr0.5W was confirmed. The effect of spheroidization time and temperature on creep strength was determined. In addition, effect of mechanical processing prior to aging, on creep strength was also determined. It was also shown that by suitable modifications of composition, the grain boundary film can be broken during the aging treatment without the use of spheroidization treatment. Microhardness, tensile and creep properties have been determined. Optical metallography and scanning electron microscopy have been used to follow the microstructural changes and mode of fracture. The creep rupture strength of alloy Ta7CrW alloy was found to be superior to many of the best commercially available ferritic alloys at 1200 0 F. (21 fig., 8 tables)

  1. Emerging good practices for Translatability Assessment (TA) of Patient-Reported Outcome (PRO) measures.

    Science.gov (United States)

    Acquadro, Catherine; Patrick, Donald L; Eremenco, Sonya; Martin, Mona L; Kuliś, Dagmara; Correia, Helena; Conway, Katrin

    2017-01-01

    This paper presents emerging Good Practices for Translatability Assessment (TA) of Patient-Reported Outcome (PRO) Measures. The ISOQOL Translation and Cultural Adaptation Special Interest Group (TCA-SIG) undertook the review of several TA approaches, with the collaboration of organizations who are involved in conducting TA, and members of the TCA-SIG. The effort led to agreement by the writing group on Good Practices for 1) the terminology to be used in referring to translatability process, 2) the best definition of TA, 3) the methodology that is recommended at each step of the process, 4) the persons involved in TA, 5) the timing of assessment, 6) the review criteria for TA, and 7) the recommendations to be made at the end of the TA process. With input from the TCA-SIG membership and in consultation with experts in the field, these emerging good practices can guide the future use of TA in the development of PROs.

  2. More Thoughts on the Mycenaean ta-ra-si-ja system

    DEFF Research Database (Denmark)

    Nosch, Marie-Louise Bech

    2006-01-01

    Discussion of the position of the Mycenaean ta-ra-si-ja system between fiscality and obligatory work......Discussion of the position of the Mycenaean ta-ra-si-ja system between fiscality and obligatory work...

  3. Fabrication of the heterostructured CsTaWO{sub 6}/Au/g-C{sub 3}N{sub 4} hybrid photocatalyst with enhanced performance of photocatalytic hydrogen production from water

    Energy Technology Data Exchange (ETDEWEB)

    Lang, Junyu; Liu, Mengqing; Su, Yiguo; Yan, Lijuan; Wang, Xiaojing, E-mail: wang_xiao_jing@hotmail.com

    2015-12-15

    Graphical abstract: - Highlights: • A novel ternary CsTaWO{sub 6}/Au/g-C{sub 3}N{sub 4} hybrid photocatalyst was successfully fabricated. • Au particles act as an electron-conduction bridge between the heterostructure. • The photoctalytic hydrogen generation was promoted by the SPR of the Au. • CsTaWO{sub 6}/Au/g-C{sub 3}N{sub 4} shows significant photocatalytic activity in H{sub 2} generation. - Abstract: In this work, a novel CsTaWO{sub 6}/Au/g-C{sub 3}N{sub 4} hybrid photocatalyst is successfully fabricated. The photocatalytic performance of the heterostructured CsTaWO{sub 6}/Au/g-C{sub 3}N{sub 4} composite was investigated. Au nanoparticles were photo-deposited as the interlayer between g-C{sub 3}N{sub 4} and the surface of CsTaWO{sub 6}, which can facilitate the photoinduced electrons migration as an electron-conduction bridge as well as increase visible-light absorption via the surface plasmon resonance. This heterostructured interface bridging by Au particles may significantly retard the recombination of electron–holes, which is beneficial to promote the photocatalytic activity under visible-light irradiation. It is found the CsTaWO{sub 6}/Au/g-C{sub 3}N{sub 4} sample showed excellent photocatalytic activity of water splitting, even higher than the sum of g-C{sub 3}N{sub 4} and Au/CsTaWO{sub 6} samples, or the sum of CsTaWO{sub 6} and Au/g-C{sub 3}N{sub 4} samples. It indicates that the heterostructured combination of g-C{sub 3}N{sub 4} and CsTaWO{sub 6} bridging by Au particles provided the synergistic photocatalytic activity driving by solar light through an efficient electron transfer process.

  4. Tuning the size-dependent He-irradiated tolerance and strengthening behavior of crystalline/amorphous Cu/Ta nanostructured multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Liang, X.Q.; Zhang, J.Y., E-mail: jinyuzhang1002@mail.xjtu.edu.cn; Wang, Y.Q.; Wu, S.H.; Zeng, F.; Wu, K.; Liu, G., E-mail: lgsammer@mail.xjtu.edu.cn; Zhang, G.J.; Sun, J.

    2016-08-30

    Nanoindentation methodology was used to measure the hardness of Cu/Ta crystalline/amorphous nanostructured multilayers (CANMs) before and after He ion-implantation at room temperature. These CANMs have a constant modulation period (λ=25 nm) but different modulation ratios (η=h{sub Ta} / h{sub Cu}) spanning from 0.11 to 1.0. It is found that in sharp contrast to previously reported Cu/Cu-Zr CANMs by Zhang et al. [9], the He-irradiated Cu/Ta samples exhibit much greater microstructure stability without radiation-induced devitrification (RID) of glassy Ta nanolayers at smaller η (except the sample at η=1.0). Both the as-deposited and irradiated Cu/Ta CANMs manifest the monotonically increased hardness with decreasing η, however, there is an unexpected transition from size-dependent irradiation hardening at η<1.0 to softening at η≥1.0 caused by a competition between dislocation-bubble interactions in crystalline nanolayers and RID in glassy nanolayers. These findings not only provide fundamental understanding of the radiation-induced defect effect on plastic characteristics of CANMs, but also offer guidance for their microstructure sensitive design for performance optimization at a critical modulation ratio under extreme conditions.

  5. Bioactivity response of Ta{sub 1-x}O{sub x} coatings deposited by reactive DC magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Almeida Alves, C.F., E-mail: cristiana.alves@fisica.uminho.pt [GRF-CFUM, Physics Departament, University of Minho, Campus of Azurem, Guimaraes 4800-058 (Portugal); Cavaleiro, A. [SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, Coimbra 3030-788 (Portugal); Carvalho, S. [GRF-CFUM, Physics Departament, University of Minho, Campus of Azurem, Guimaraes 4800-058 (Portugal); SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, Coimbra 3030-788 (Portugal)

    2016-01-01

    The use of dental implants is sometimes accompanied by failure due to periimplantitis disease and subsequently poor esthetics when soft–hard tissue margin recedes. As a consequence, further research is needed for developing new bioactive surfaces able to enhance the osseous growth. Tantalum (Ta) is a promising material for dental implants since, comparing with titanium (Ti), it is bioactive and has an interesting chemistry which promotes the osseointegration. Another promising approach for implantology is the development of implants with oxidized surfaces since bone progenitor cells interact with the oxide layer forming a diffusion zone due to its ability to bind with calcium which promotes a stronger bond. In the present report Ta-based coatings were deposited by reactive DC magnetron sputtering onto Ti CP substrates in an Ar + O{sub 2} atmosphere. In order to assess the osteoconductive response of the studied materials, contact angle and in vitro tests of the samples immersed in Simulated Body Fluid (SBF) were performed. Structural results showed that oxide phases where achieved with larger amounts of oxygen (70 at.% O). More compact and smooth coatings were deposited by increasing the oxygen content. The as-deposited Ta coating presented the most hydrophobic character (100°); with increasing oxygen amount contact angles progressively diminished, down to the lowest measured value, 63°. The higher wettability is also accompanied by an increase on the surface energy. Bioactivity tests demonstrated that highest O-content coating, in good agreement with wettability and surface energy values, showed an increased affinity for apatite adhesion, with higher Ca/P ratio formation, when compared to the bare Ti substrates. - Highlights: • Ta{sub 1-x}O{sub x} coatings were deposited by reactive DC magnetron sputtering. • Amorphous oxide phases were achieved with higher oxygen amounts. • Contact angles progressively diminished, with increasing oxygen content. • Ta

  6. Temperature-dependent surface modification of Ta due to high-flux, low-energy He+ ion irradiation

    International Nuclear Information System (INIS)

    Novakowski, T.J.; Tripathi, J.K.; Hassanein, A.

    2015-01-01

    This work examines the response of Tantalum (Ta) as a potential candidate for plasma-facing components (PFCs) in future nuclear fusion reactors. Tantalum samples were exposed to high-flux, low-energy He + ion irradiation at different temperatures in the range of 823–1223 K. The samples were irradiated at normal incidence with 100 eV He + ions at constant flux of 1.2 × 10 21 ions m −2  s −1 to a total fluence of 4.3 × 10 24 ions m −2 . An additional Ta sample was also irradiated at 1023 K using a higher ion fluence of 1.7 × 10 25 ions m −2 (at the same flux of 1.2 × 10 21 ions m −2  s −1 ), to confirm the possibility of fuzz formation at higher fluence. This higher fluence was chosen to roughly correspond to the lower fluence threshold of fuzz formation in Tungsten (W). Surface morphology was characterized with a combination of field-emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). These results demonstrate that the main mode of surface damage is pinholes with an average size of ∼70 nm 2 for all temperatures. However, significantly larger pinholes are observed at elevated temperatures (1123 and 1223 K) resulting from the agglomeration of smaller pinholes. Ex situ X-ray photoelectron spectroscopy (XPS) provides information about the oxidation characteristics of irradiated surfaces, showing minimal exfoliation of the irradiated Ta surface. Additionally, optical reflectivity measurements are performed to further characterize radiation damage on Ta samples, showing gradual reductions in the optical reflectivity as a function of temperature.

  7. Surface modification of Ti-30Ta alloy by electrospun PCL deposition

    Energy Technology Data Exchange (ETDEWEB)

    Wada, C.M.; Rangel, A.L.R.; Souza, M.A. de; Claro, A.P.R.A.; Rezende, M.C.R. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), SP (Brazil); Almeida, R. dos S. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil)

    2014-07-01

    Full text: Surface modifications techniques have been used for change the inert surface of the titanium alloys for better interaction. Ingots of the experimental alloy Ti30Ta were melted in an arc furnace and re-melted ten times at least. They were homogenized under vacuum at 1000 °C for 86. 4 ks to eliminate chemical segregation and cold-worked by swaging. Discs were immersed in aqueous NaOH solution for 24 h, dried at room temperature, immersed in HCl and dried at 40 °C in oven for 24 hours. Followed, PCL fibers were deposited on the Ti30Ta alloy discs surfaces by electrospinning. Plasma treatment was carried out for change PCL electrospun by using stainless steel plasma reactor. Samples were immersed in SBF 5x solution for apatite growth. Surfaces were evaluated by using SEM, X-rays diffraction and contact angle. Samples exhibited hydrophilic behavior after plasma treatment and SBF immersion. Results are very interesting for biomedical applications. (author)

  8. Deformation effects during hydride transformations in the Ta-H system

    International Nuclear Information System (INIS)

    Spivak, L.V.; Kats, M.Ya.

    1991-01-01

    A behavior of alloys with hydrogen constant content under thermocycling in stress fields and deformation effects in thermodynamically closed system of Ta-H are considered. Effect of hydrogenized tantalum heating and cooling on differential electroresistance, shear modulus and internal friction have been investigated. Spontaneuous deformation (twist effect) has been established under heating of hydrogenized and homogenized tantalum after prethermocycling of unloaded samples at hydroidation transition temperature. Cooling from homogeneous area under a load less than yield-point is accompanied by significant deformation at the temperature of hydridation.Investigated results enable one to conclude that observed deformation comprises a transition plasticity effect. Sample heating under no-load conditions leads to recovery of deformation accumulated during cooling. Besides it has been revealed that deformation of oriented transformation (DOT) exibits in Ta-H system. By this means the shape memory effect obtained as well as DOT demonstrated experimentally for the first time. Observed deformation effects are considered as a result of oriented growth or disapear of hydride crystals according to the deformation sheme

  9. Surface modification of Ti-30Ta alloy by electrospun PCL deposition

    International Nuclear Information System (INIS)

    Wada, C.M.; Rangel, A.L.R.; Souza, M.A. de; Claro, A.P.R.A.; Rezende, M.C.R.; Almeida, R. dos S.

    2014-01-01

    Full text: Surface modifications techniques have been used for change the inert surface of the titanium alloys for better interaction. Ingots of the experimental alloy Ti30Ta were melted in an arc furnace and re-melted ten times at least. They were homogenized under vacuum at 1000 °C for 86. 4 ks to eliminate chemical segregation and cold-worked by swaging. Discs were immersed in aqueous NaOH solution for 24 h, dried at room temperature, immersed in HCl and dried at 40 °C in oven for 24 hours. Followed, PCL fibers were deposited on the Ti30Ta alloy discs surfaces by electrospinning. Plasma treatment was carried out for change PCL electrospun by using stainless steel plasma reactor. Samples were immersed in SBF 5x solution for apatite growth. Surfaces were evaluated by using SEM, X-rays diffraction and contact angle. Samples exhibited hydrophilic behavior after plasma treatment and SBF immersion. Results are very interesting for biomedical applications. (author)

  10. Chorionic villus sampling for beta-thalassemia: the first report of experience in Iran.

    Science.gov (United States)

    Akhlaghpoor, Shahram

    2006-12-01

    Beta-thalassemia is one of the most common hereditary disorders in Iran. The prenatal diagnosis of beta-thalassemia is part of a control program in our country and it began 13 years ago. During the past 8 years the number of procedures has increased significantly as also the legal abortions. This is the first report made on the CVS program in Iran. One thousand six hundred and sixty-one cases of transabdominal Chorionic Villus Sampling (CVS) have been retrospectively evaluated. Among them 1381 cases had inclusion criteria. CVS results, complications and fetal loss rate were evaluated. The distributions of the population at risk were divided between eight regions that have been proposed for beta-thalassemia mapping previously. The mean age of the patients was 26.2 +/- 5.2 years with mean gestational age of 11.4 +/- 1.4 weeks. CVS was successful in all the patients (100%) although 1% required a second procedure. Post CVS fetal loss was 1.45%. Other minor complications were bleeding or spotting (1.81%), amniotic fluid leak (0.5%), small sub-chorionic hematoma (0.58%), severe abdominal pain (0.6%) and severe vasovagal reaction (0.14%). Late complications were seen in 0.21% (oligohydraminos). Approximately 2/3 of the patients were referred from three regions of the country, North (26.8%), South West (22.4%), Central (19.5%) and the remainder (31.3%) were from the other five regions. CVS is a safe and effective method for prenatal diagnosis of beta-thalassemia in countries with a high prevalence as in Iran. The overall complication rate is quite low and acceptable. Fortunately the recent acceptance of legal abortion with respect to Muslim rules has increased the effectiveness of the procedure and made great advances in its application in Iran. Correspondingly, social knowledge has also improved but still there is a gap between the population at risk and the required prenatal diagnosis laboratories and sampling centers. 2006 John Wiley & Sons, Ltd.

  11. Electrode contacts on ferroelectric Pb(Zr x Ti1−x )O3 and SrBi2Ta2O9 thin films and their influence on fatigue properties

    OpenAIRE

    Lee, J. J.; Thio, C. L.; Desu, Seshu B.

    1995-01-01

    The degradation (fatigue) of dielectric properties of ferroelectric Pb(ZrxTi1-x)O-3 (PZT) and SrBi2Ta2O9 thin films during cycling was investigated. PZT and SrBi2Ta2O9 thin films were fabricated by metalorganic decomposition and pulsed laser deposition, respectively. Samples with electrodes of platinum (Pt) and ruthenium oxide (RuO2) were studied. The interfacial capacitance (if any) at the Pt/PZT, RuO2/PZT, and Pt/SrBi2Ta2O9 interfaces was determined from the thickness dependence of low-fiel...

  12. Experimental and Numerical Studies on Self-Propagating High-Temperature Synthesis of Ta5Si3 Intermetallics

    Directory of Open Access Journals (Sweden)

    Chun-Liang Yeh

    2015-09-01

    Full Text Available Formation of Ta5Si3 by self-propagating high-temperature synthesis (SHS from elemental powder compacts of Ta:Si = 5:3 was experimentally and numerically studied. Experimental evidence showed that the increase of either sample density or preheating temperature led to the increase of combustion wave velocity and reaction temperature. The apparent activation energy, Ea ≈ 108 kJ/mol, was determined for the synthesis reaction. Based upon numerical simulation, the Arrhenius factor of the rate function, K0 = 2.5 × 107 s−1, was obtained for the 5Ta + 3Si combustion system. In addition, the influence of sample density on combustion wave kinetics was correlated with the effective thermal conductivity (keff of the powder compact. By adopting 0.005 ≤ keff/kbulk ≤ 0.016 in the computation model, the calculated combustion velocity and temperature were in good agreement with experimental data of the samples with compaction densities between 35% and 45% theoretical maximum density (TMD.

  13. Mechanism of n-butane hydrogenolysis promoted by Ta-hydrides supported on silica

    KAUST Repository

    Pasha, Farhan Ahmad; Cavallo, Luigi; Basset, Jean-Marie

    2014-01-01

    (III)H is rapidly trapped by molecular hydrogen to form the more stable tris-hydride (≡ Si-O-) 2Ta(V)H3. Loading of n-butane to the Ta-center occurs through C-H activation concerted with elimination of molecular hydrogen (σ-bond metathesis). Once the Ta

  14. Atomistic simulation of the point defects in TaW ordered alloy

    Indian Academy of Sciences (India)

    atom method (MAEAM), the formation, migration and activation energies of the point defects for six-kind migration mechanisms in B2-type TaW alloy have been investigated. The results showed that the anti-site defects TaW and WTa were easier to form than Ta and W vacancies owing to their lower formation energies.

  15. Determination of the enthalpy of fusion of K{sub 3}TaF{sub 8} and K{sub 3}TaOF{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Kosa, L. [Institute of Inorganic Chemistry, Slovak Academy of Sciences, SK-845 36 Bratislava (Slovakia)]. E-mail: uachkosa@savba.sk; Mackova, I. [Institute of Inorganic Chemistry, Slovak Academy of Sciences, SK-845 36 Bratislava (Slovakia)

    2006-08-15

    The areas of the fusion and crystallization peaks of K{sub 3}TaF{sub 8} and K{sub 3}TaOF{sub 6} have been measured using the DSC mode of the high-temperature calorimeter (SETARAM 1800 K). On the basis of these quantities and the temperature dependence of the used calorimetric method sensitivity, the values of the enthalpy of fusion of K{sub 3}TaF{sub 8} at temperature of fusion 1039 K: {delta}{sub fus} H {sub m}(K{sub 3}TaF{sub 8}; 1039 K) = (52 {+-} 2) kJ mol{sup -1} and of K{sub 3}TaOF{sub 6} at temperature of fusion 1055 K: {delta}{sub fus} H {sub m}(K{sub 3}TaOF{sub 6}; 1055 K) = (62 {+-} 3) kJ mol{sup -1} have been determined.

  16. Proposal of guideline for bonding to prevention of hydrogen embrittlement at Ta/Zr bond interface. Hydrogen embrittlement in SUS304ULC/Ta/Zr explosive bonded joint

    International Nuclear Information System (INIS)

    Saida, Kazuyoshi; Fujimoto, Tetsuya; Nishimoto, Kazutoshi

    2010-01-01

    The occurrence condition of hydrogen embrittlement cracking at Ta/Zr bond interface was investigated with respect to the hydrogen content and applied stress in order to propose a guideline for the explosive bonding procedure to prevention of hydrogen embrittlement. Hydrogen charging test was conducted for SUS304ULC/Ta/Zr explosive bonded joints applied the different flexural strains. A hydrogen embrittlement crack occurred in the Zr substrate at Ta/Zr bond interface after hydrogen charging, and it was initiated at shorter charging times when the augmented strain was increased. The occurrence condition of hydrogen embrittlement cracking at Ta/Zr bond interface was shifted to lower stress and hydrogen content with an increase in the amount of explosive during bonding. It was suggested that hydrogen embrittlement in Ta/Zr explosive bonded joint could be inhibited by reducing the initial hydrogen content in Ta substrate less than approx. 5 ppm. (author)

  17. Sampling free energy surfaces as slices by combining umbrella sampling and metadynamics.

    Science.gov (United States)

    Awasthi, Shalini; Kapil, Venkat; Nair, Nisanth N

    2016-06-15

    Metadynamics (MTD) is a very powerful technique to sample high-dimensional free energy landscapes, and due to its self-guiding property, the method has been successful in studying complex reactions and conformational changes. MTD sampling is based on filling the free energy basins by biasing potentials and thus for cases with flat, broad, and unbound free energy wells, the computational time to sample them becomes very large. To alleviate this problem, we combine the standard Umbrella Sampling (US) technique with MTD to sample orthogonal collective variables (CVs) in a simultaneous way. Within this scheme, we construct the equilibrium distribution of CVs from biased distributions obtained from independent MTD simulations with umbrella potentials. Reweighting is carried out by a procedure that combines US reweighting and Tiwary-Parrinello MTD reweighting within the Weighted Histogram Analysis Method (WHAM). The approach is ideal for a controlled sampling of a CV in a MTD simulation, making it computationally efficient in sampling flat, broad, and unbound free energy surfaces. This technique also allows for a distributed sampling of a high-dimensional free energy surface, further increasing the computational efficiency in sampling. We demonstrate the application of this technique in sampling high-dimensional surface for various chemical reactions using ab initio and QM/MM hybrid molecular dynamics simulations. Further, to carry out MTD bias reweighting for computing forward reaction barriers in ab initio or QM/MM simulations, we propose a computationally affordable approach that does not require recrossing trajectories. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  18. HIP (hot isostatic pressing) sintering of Tantalum (Ta) and tantalum carbide (TaC) powder mixture: relations between microstructure and properties

    International Nuclear Information System (INIS)

    Valin, F.; Schnedecker, M.

    1994-01-01

    HIP sintering at 1630 C and 195 MPa, during 2 hours, can be used for complete densification of mixtures of commercial tantalum carbide and tantalum powders. HIPed material properties are depending upon initial compositions. For C/Ta ratios inferior to 80%, the monocarbide structure is preserved. A partial ordering of the carbon vacancies will result, for TaC(0.80), in microhardness maximization. The microstructurally homogenous TaC(0.45) shows an excellent toughness. 2 figs., 2 refs

  19. From Ba3Ta5O14N to LaBa2Ta5O13N2: Decreasing the optical band gap of a photocatalyst

    International Nuclear Information System (INIS)

    Anke, B.; Bredow, T.; Pilarski, M.; Wark, M.; Lerch, M.

    2017-01-01

    Yellow LaBa 2 Ta 5 O 13 N 2 was successfully synthesized as phase-pure material crystallizing isostructurally to previously reported Ba 3 Ta 5 O 14 N and mixed-valence Ba 3 Ta V 4 Ta IV O 15 . The electronic structure of LaBa 2 Ta 5 O 13 N 2 was studied theoretically with the range-separated hybrid method HSE06. The most stable structure was obtained when lanthanum was placed on 2a and nitrogen on 4h sites confirming Pauling's second rule. By incorporating nitrogen, the measured band gap decreases from ∼3.8 eV for the oxide via 2.74 eV for Ba 3 Ta 5 O 14 N to 2.63 eV for the new oxide nitride, giving rise to an absorption band well in the visible-light region. Calculated fundamental band gaps confirm the experimental trend. The atom-projected density of states has large contributions from N2p orbitals close to the valence band edge. These are responsible for the observed band gap reduction. Photocatalytic hydrogen formation was investigated and compared with that of Ba 3 Ta 5 O 14 N revealing significantly higher activity for LaBa 2 Ta 5 O 13 N 2 under UV-light. - Graphical abstract: X-ray powder diffraction pattern of LaBa 2 Ta 5 O 13 N 2 with the results of the Rietveld refinements. Inset: Unit cell of LaBa 2 Ta 5 O 13 N 2 and polyhedral representation of the crystal structure. - Highlights: • Synthesis of a new oxide nitride LaBa 2 Ta 5 O 13 N 2 . • Refinement of the crystal structure. • Quantum chemical calculations provided band gap close to the measured value. • New phase shows a higher photocatalytic H 2 evolution rate compared to prior tested Ba 3 Ta 5 O 14 N.

  20. Wheat Brassinosteroid-Insensitive1 (TaBRI1 Interacts with Members of TaSERK Gene Family and Cause Early Flowering and Seed Yield Enhancement in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Akanksha Singh

    Full Text Available Brassinosteroids (BRs hormones are important for plant growth, development and immune responses. They are sensed by the transmembrane receptor kinase Brassinosteroid-Insensitive 1 (BRI1 when they bind to its extracellular Leu-rich repeat (LRR domain. We cloned and characterized the TaBRI1 from T. aestivum and raised overexpression transgenics in Arabidopsis to decipher its functional role. TaBRI1 protein consists of a putative signal peptide followed by 25 leucine rich repeats (LRR, a transmembrane domain and a C-terminal kinase domain. The analysis determined the interaction of TaBRI1 with five members of the wheat Somatic Embryogenesis Receptor Kinase (TaSERKs gene family (TaSERK1, TaSERK2, TaSERK3, TaSERK4 and TaSERK5, at the plasma membrane. Furthermore, overexpression of TaBRI1 in Arabidopsis leads to the early flowering, increased silique size and seed yield. Root growth analysis of TaBRI1 overexpressing transgenic plants showed hypersensitivity to epi-brassinolide (epi-BL hormone in a dose-dependent manner. Interestingly, transgenic Arabidopsis plants show thermotolerance phenotype at the seedling stages as revealed by chlorophyll content, photosystem II activity and membrane stability. The transcriptome profiling on the basis of microarray analysis indicates up-regulation of several genes related to brassinosteroid signaling pathway, abiotic stress response, defense response and transcription factors. These studies predict the possible role of TaBRI1 gene in plant growth and development imparting tolerance to thermal stress.

  1. Computer simulation of hydrogen diffusion and hydride precipitation at Ta/Zr bond interface. Hydrogen embrittlement in SUS304ULC/Ta/Zr explosive bonded joint

    International Nuclear Information System (INIS)

    Saida, Kazuyoshi; Fujimoto, Tetsuya; Nishimoto, Kazutoshi

    2010-01-01

    The concentration of hydrogen and precipitation of zirconium hydrides in Ta/Zr explosive bonded joint were analysed by computer simulation. Numerical model of hydride precipitation under hydrogen diffusion was simplified by the alternate model coupled the macroscopic hydrogen diffusion with the microscopic hydride precipitation. Effects of the initial hydrogen content in Ta, working degree of Zr and post-bond heat treatment on the hydrogen diffusion and hydride precipitation were investigated. Hydrogen was rapidly diffused from Ta substrate into Zr after explosive bonding and temporarily concentrated at Ta/Zr bond interface. Zirconium hydrides were precipitated and grew at Ta/Zr bond interface, and the precipitation zone of hydrides was enlarged with the lapse of time. The precipitation of zirconium hydrides was promoted when the initial hydrogen content in Ta and working degree of Zr were increased. The concentration of hydrogen and precipitation of hydrides at the bond interface were reduced and diminished by post-bond heat treatment at 373 K. It was deduced that hydrogen embrittlement in Ta/Zr explosive bonded joint was caused by the precipitation of zirconium hydrides and concentration of hydrogen at Ta/Zr bond interface during the diffusion of hydrogen containing in Ta substrate. (author)

  2. Combined experimental and theoretical assessments of the lattice dynamics and optoelectronics of TaON and Ta{sub 3}N{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Nurlaela, Ela; Harb, Moussab [Division of Physical Sciences and Engineering, KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), 4700 KAUST, Thuwal 23955-6900 Saudi Arabia (Saudi Arabia); Gobbo, Silvano del [Solar and Photovoltaic Engineering Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia); Vashishta, Manish [Division of Physical Sciences and Engineering, KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), 4700 KAUST, Thuwal 23955-6900 Saudi Arabia (Saudi Arabia); Takanabe, Kazuhiro, E-mail: kazuhiro.takanabe@kaust.edu.sa [Division of Physical Sciences and Engineering, KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), 4700 KAUST, Thuwal 23955-6900 Saudi Arabia (Saudi Arabia)

    2015-09-15

    Presented herein is a detailed discussion of the properties of the lattice dynamic and optoelectronic properties of tantalum(V) oxynitride (TaON) and tantalum(V) nitride (Ta{sub 3}N{sub 5}), from experimental and theoretical standpoint. The active Raman and infra red (IR) frequencies of TaON and Ta{sub 3}N{sub 5} were measured using confocal Raman and Fourier Transform Infrared spectroscopies (FTIR) and calculated using the linear response method within the density functional perturbation theory (DFPT). The detailed study leads to an exhaustive description of the spectra, including the symmetry of the vibrational modes. Electronic structures of these materials were computed using DFT within the range-separated hybrid HSE06 exchange–correlation formalism. Electronic and ionic contributions to the dielectric constant tensors of these materials were obtained from DFPT within the linear response method using the PBE functional. Furthermore, effective mass of photogenerated holes and electrons at the band edges of these compounds were computed from the electronic band structure obtained at the DFT/HSE06 level of theory. The results suggest that anisotropic nature in TaON and Ta{sub 3}N{sub 5} is present in terms of dielectric constant and effective masses. - Graphical abstract: Detailed investigation has been conducted from combined experimental and theoretical approaches on Raman and IR spectroscopies, electronic structures, dielectric constants and effective masses of TaON and Ta{sub 3}N{sub 5}. - Highlights: • Crystal structures of TaON and Ta{sub 3}N{sub 5} are discussed based on XRD and DFT calculation. • Raman and IR spectra of TaON and Ta{sub 3}N{sub 5} materials are measured and computed by DFPT method. • Optoelectronic properties of TaON and Ta{sub 3}N{sub 5} are discussed. • Dielectric constant and effective masses of TaON and Ta{sub 3}N{sub 5} are calculated.

  3. TDPAC characterization of tin oxides using 181Ta

    International Nuclear Information System (INIS)

    Moreno, M.S.; Desimoni, J.; Requejo, F.G.; Renteria, M.; Bibiloni, A.G.

    1991-01-01

    In connection with a general study of the evolution of tin-oxygen thin films, we report here on the hyperfine interactions of 181 Ta substitutionally replacing tin in the isolated phases SnO and SnO 2 . For this purpose, pure SnO pressed powder and a thin SnO 2 film were implanted with 181 Hf. In both cases, unique quadrupole frequencies were found after thermal annealing treatments. The results indicate that the following hyperfine parameters: ν Q =740.6(2.1) MHz, η=0.07(2) and ν Q =971.5(1.9) MHz, η=0.72(1) characterize 181 Ta and SnO and SnO 2 , respectively. (orig.)

  4. Shock Hugoniot measurements on Ta to 0.78 TPa

    International Nuclear Information System (INIS)

    Froeschner, K.E.; Lee, R.S.; Chau, H.H.; Weingart, R.C.

    1983-01-01

    Symmetric impact shock Hugoniot measurements have been made on Ta with an electrically exploded foil gun system. The results obtained to date for the Hugoniot of Ta cover the range 0.19 to 0.78 TPa (impact velocities from 4.0 to 9.7 km/s) and agree with data obtained by other researchers to within 2.7% rms. Recent improvements in the system include electromagnetic shielding of impactor and target, continuous measurement of impactor velocity with a Fabry-Perot interferometer and computer-aided analysis of shot film. Conservative extrapolation from current operating conditions indicate that pressures of 1.1 to 1.5 TPa could be achieved with little difficulty

  5. A new compound - Ta3Pb : manufacture, structure and properties

    International Nuclear Information System (INIS)

    Tuleushev, A.Zh.; Tuleushev, Yu.Zh.; Volodin, V.N.; Zhakanbaev, E.A.

    2003-01-01

    For the first time by the magnetron sputtering and tantalum deposition on substrates from molybdenum and tungsten the covers presenting the lead solution in cubic α-tantalum (up to 2.5 at % Pb) were obtained. The lead dissolution is accompanying by the Ta lattice parameter increasing from 0.3314 to 0.3321 nm in the lead concentration range from 0.2 to 2.5 at. % Pb. The cryogenic examinations of the synthesised covers conducted by four-probes electric resistance method show the absence the superconductivity up to the 4.2 K temperature. So, for the first time the Ta 2 Pb compound with A15 structure was synthesised and data for its identification were determined

  6. The current status and prospect of the TA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Kasahara, K. [Faculty of Systems Engineering, Dept. of Electronic and Information Systems, Minuma-ku, Saitama-shi, Saitama (Japan)

    2005-07-01

    The Telescope Array (TA) experiment is designed to observe cosmic-ray-induced air showers at extremely high energies. It is being deployed in a desert of Utah (Usa); an array of 3 m{sup 2} scintillation counters will be distributed over 760 km{sup 2} and 3 sets of air fluorescence telescopes will be placed in the perimeter of the array. Its primary purpose is to make a decisive measurement of the cosmic ray spectrum in the GZK (Greisen, Zatsepin and Kuzmin) cutoff region. We expect the first data from the TA in the spring 2007. As its unique features are included: 1) hybrid measurement planned down to 10{sup 17.5} eV; 2) calibration of fluorescence detection by using artificial air showers generated by an electron line; and 3) interaction model calibration by the LHC. (author)

  7. Anomalous electronic structure and magnetoresistance in TaAs2.

    Science.gov (United States)

    Luo, Yongkang; McDonald, R D; Rosa, P F S; Scott, B; Wakeham, N; Ghimire, N J; Bauer, E D; Thompson, J D; Ronning, F

    2016-06-07

    The change in resistance of a material in a magnetic field reflects its electronic state. In metals with weakly- or non-interacting electrons, the resistance typically increases upon the application of a magnetic field. In contrast, negative magnetoresistance may appear under some circumstances, e.g., in metals with anisotropic Fermi surfaces or with spin-disorder scattering and semimetals with Dirac or Weyl electronic structures. Here we show that the non-magnetic semimetal TaAs2 possesses a very large negative magnetoresistance, with an unknown scattering mechanism. Density functional calculations find that TaAs2 is a new topological semimetal [ℤ2 invariant (0;111)] without Dirac dispersion, demonstrating that a negative magnetoresistance in non-magnetic semimetals cannot be attributed uniquely to the Adler-Bell-Jackiw chiral anomaly of bulk Dirac/Weyl fermions.

  8. TaER Expression Is Associated with Transpiration Efficiency Traits and Yield in Bread Wheat.

    Science.gov (United States)

    Zheng, Jiacheng; Yang, Zhiyuan; Madgwick, Pippa J; Carmo-Silva, Elizabete; Parry, Martin A J; Hu, Yin-Gang

    2015-01-01

    ERECTA encodes a receptor-like kinase and is proposed as a candidate for determining transpiration efficiency of plants. Two genes homologous to ERECTA in Arabidopsis were identified on chromosomes 6 (TaER2) and 7 (TaER1) of bread wheat (Triticum aestivum L.), with copies of each gene on the A, B and D genomes of wheat. Similar expression patterns were observed for TaER1 and TaER2 with relatively higher expression of TaER1 in flag leaves of wheat at heading (Z55) and grain-filling (Z73) stages. Significant variations were found in the expression levels of both TaER1 and TaER2 in the flag leaves at both growth stages among 48 diverse bread wheat varieties. Based on the expression of TaER1 and TaER2, the 48 wheat varieties could be classified into three groups having high (5 varieties), medium (27 varieties) and low (16 varieties) levels of TaER expression. Significant differences were also observed between the three groups varying for TaER expression for several transpiration efficiency (TE)- related traits, including stomatal density (SD), transpiration rate, photosynthetic rate (A), instant water use efficiency (WUEi) and carbon isotope discrimination (CID), and yield traits of biomass production plant-1 (BYPP) and grain yield plant-1 (GYPP). Correlation analysis revealed that the expression of TaER1 and TaER2 at the two growth stages was significantly and negatively associated with SD (Ptranspiration rate (Ptranspiration efficiency -related traits and yield in bread wheat, implying a function for TaER in regulating leaf development of bread wheat and contributing to expression of these traits. Moreover, the results indicate that TaER could be exploitable for manipulating important agronomical traits in wheat improvement.

  9. Evaluation of the physical stability and local crystallization of amorphous terfenadine using XRD-DSC and micro-TA

    International Nuclear Information System (INIS)

    Yonemochi, Etsuo; Hoshino, Takafumi; Yoshihashi, Yasuo; Terada, Katsuhide

    2005-01-01

    It is very difficult to follow rapid changes in polymorphic transformation and crystallization and to estimate the species recrystallized from the amorphous form. The aim of this study was to clarify the structural changes of amorphous terfenadine and to evaluate the polymorphs crystallized from amorphous samples using XRD-DSC and an atomic force microscope with a thermal probe (micro-TA). Amorphous samples were prepared by grinding or rapid cooling of the melt. The rapid structural transitions of samples were followed by the XRD-DSC system. On the DSC trace of the quenched terfenadine, two exotherms were observed, while only one exothermic peak was observed in the DSC scan of a ground sample. From the in situ data obtained by the XRD-DSC system, the stable form of terfenadine was recrystallized during heating of the ground amorphous sample, whereas the metastable form was recrystallized from the quenched amorphous sample and the crystallized polymorph changed to the stable form. Obtained data suggested that recrystallized species could be related to the homogeneity of samples. When the stored sample surface was scanned by atomic force microscopy (AFM), heterogeneous crystallization was observed. By using micro-TA, melting temperatures at various points were measured, and polymorph forms I and II were crystallized in each region. The percentages of the crystallized form I stored at 120 and 135 deg C were 47 and 79%, respectively. This result suggested that increasing the storage temperature increased the crystallization of form I, the stable form, confirming the temperature dependency of the crystallized form. The crystallization behavior of amorphous drug was affected by the annealing temperature. Micro-TA would be useful for detecting the inhomogeneities in polymorphs crystallized from amorphous drug

  10. Due testimonianze di Josip Vaništa

    Directory of Open Access Journals (Sweden)

    Radmila Iva Janković

    2013-12-01

    Full Text Available Radmila Iva Janković ha intervistato nel luglio 2013 Josip Vaništa, artista che aveva partecipato al gruppo Gorgona e preso parte alla residenza d'artista a Brunnenburg nel 1991, organizzata da Francesco Conz con l'obiettivo di includere il gruppo di artisti nel progetto La Livre, una monumentale edizione d'artista dedicata a Ezra Pound.

  11. Issues for reuse of gloveboxes at LANL TA-55

    Energy Technology Data Exchange (ETDEWEB)

    Cadwallader, L.C.; Pinson, P.A.; Miller, C.F.

    1998-08-01

    This report is a summary of issues that face plutonium glovebox designers and users at the Los Alamos National Laboratory (LANL) Technical Area 55 (TA-55). Characterizing the issues is a step in the task of enhancing the next generation glovebox design to minimize waste streams while providing the other design functions. This report gives an initial assessment of eight important design and operation issues that can benefit from waste minimization.

  12. TA53:19 Reverb Chamber Quick-Look

    Energy Technology Data Exchange (ETDEWEB)

    Bishofberger, Kip A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-19

    Within Building 19 of TA-53, a screen room has been evaluated for use as a reverb chamber (with deep gratitude to Dale Dalmas and Greg Dale for their assistance). With minimal additional sealing of the chamber, we expect the Q to increase even more, and thus field levels for the same RF source power. Future studies need to determine leakage field levels, which will define maximum achievable field levels.

  13. Issues for reuse of gloveboxes at LANL TA-55

    International Nuclear Information System (INIS)

    Cadwallader, L.C.; Pinson, P.A.; Miller, C.F.

    1998-08-01

    This report is a summary of issues that face plutonium glovebox designers and users at the Los Alamos National Laboratory (LANL) Technical Area 55 (TA-55). Characterizing the issues is a step in the task of enhancing the next generation glovebox design to minimize waste streams while providing the other design functions. This report gives an initial assessment of eight important design and operation issues that can benefit from waste minimization

  14. Correlation between thermodynamic and mechanical properties in Ta-W

    Energy Technology Data Exchange (ETDEWEB)

    Hoppe, Sandra; Mueller, Stefan [Institute of Advanced Ceramics, Hamburg University of Technology, Hamburg (Germany)

    2015-07-01

    Varying an alloy's concentration or alloying constituents strongly influences its structural and mechanical properties. Modern simulation methods like density functional theory in combination with the cluster expansion make the whole configurational space accessible. This way, also metastable structures may be considered, which are experimentally difficult to obtain. Recent results for several face-centered cubic (fcc) binary metal alloys suggest a linear correlation between thermodynamic stability and elastic properties at a fixed stoichiometry. This study aims to investigate the generality of these findings by considering a similar correlation for binary body-centered cubic (bcc) alloys. As a model system, Ta-W was chosen due to its simple phase diagram with solid solution in the whole concentration range. Interestingly, the elastic constants c{sub 44} and c{sub 12} show an opposing trend to that observed for fcc alloys: Energetically favorable structures are mechanically weaker than those further away from the ground-state line. This phenomenon may be related to the anomalous behavior of c{sub 44} with increasing pressure or temperature, which has been reported in the literature for Ta-W. We will discuss the interesting behavior of Ta-W with regard to its electronic structure.

  15. Seismic assessment of Technical Area V (TA-V).

    Energy Technology Data Exchange (ETDEWEB)

    Medrano, Carlos S.

    2014-03-01

    The Technical Area V (TA-V) Seismic Assessment Report was commissioned as part of Sandia National Laboratories (SNL) Self Assessment Requirement per DOE O 414.1, Quality Assurance, for seismic impact on existing facilities at Technical Area-V (TA-V). SNL TA-V facilities are located on an existing Uniform Building Code (UBC) Seismic Zone IIB Site within the physical boundary of the Kirtland Air Force Base (KAFB). The document delineates a summary of the existing facilities with their safety-significant structure, system and components, identifies DOE Guidance, conceptual framework, past assessments and the present Geological and Seismic conditions. Building upon the past information and the evolution of the new seismic design criteria, the document discusses the potential impact of the new standards and provides recommendations based upon the current International Building Code (IBC) per DOE O 420.1B, Facility Safety and DOE G 420.1-2, Guide for the Mitigation of Natural Phenomena Hazards for DOE Nuclear Facilities and Non-Nuclear Facilities.

  16. The wheat WRKY transcription factors TaWRKY49 and TaWRKY62 confer differential high-temperature seedling-plant resistance to Puccinia striiformis f. sp. tritici.

    Directory of Open Access Journals (Sweden)

    Junjuan Wang

    Full Text Available WRKY transcription factors (TFs play crucial roles in plant resistance responses to pathogens. Wheat stripe rust, caused by the fungal pathogen Puccinia striiformis f. sp. tritici (Pst, is a destructive disease of wheat (Triticum aestivum worldwide. In this study, the two WRKY genes TaWRKY49 and TaWRKY62 were originally identified in association with high-temperature seedling-plant resistance to Pst (HTSP resistance in wheat cultivar Xiaoyan 6 by RNA-seq. Interestingly, the expression levels of TaWRKY49 and TaWRKY62 were down- and up-regulated, respectively, during HTSP resistance in response to Pst. Silencing of TaWRKY49 enhanced whereas silencing TaWRKY62 reduced HTSP resistance. The enhanced resistance observed on leaves following the silencing of TaWRKY49 was coupled with increased expression of salicylic acid (SA- and jasmonic acid (JA-responsive genes TaPR1.1 and TaAOS, as well as reactive oxygen species (ROS-associated genes TaCAT and TaPOD; whereas the ethylene (ET-responsive gene TaPIE1 was suppressed. The decreased resistance observed on leaves following TaWRKY62 silencing was associated with increased expression of TaPR1.1 and TaPOD, and suppression of TaAOS and TaPIE1. Furthermore, SA, ET, MeJA (methyl jasmonate, hydrogen peroxide (H2O2 and abscisic acid (ABA treatments increased TaWRKY62 expression. On the other hand, MeJA did not affect the expression of TaWRKY49, and H2O2 reduced TaWRKY49 expression. In conclusion, TaWRKY49 negatively regulates while TaWRKY62 positively regulates wheat HTSP resistance to Pst by differential regulation of SA-, JA-, ET and ROS-mediated signaling.

  17. Photocatalytic hydrogen production using visible-light-responsive Ta{sub 3}N{sub 5} photocatalyst supported on monodisperse spherical SiO{sub 2} particulates

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaoming [Division of Physical Sciences and Engineering, KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), 4700 KAUST, Thuwal 23955-6900 (Saudi Arabia); School of Environment and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Zhao, Lan [Advanced Nanofabrication, Imaging and Characterization Core Lab, King Abdullah University of Science and Technology (KAUST), 4700 KAUST, Thuwal 23955-6900 (Saudi Arabia); Domen, Kazunari [Department of Chemical System Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Takanabe, Kazuhiro, E-mail: kazuhiro.takanabe@kaust.edu.sa [Division of Physical Sciences and Engineering, KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), 4700 KAUST, Thuwal 23955-6900 (Saudi Arabia)

    2014-01-01

    Graphical abstract: A simple and effective sol–gel process followed by nitridation in an NH{sub 3} flow has been developed to deposit Ta{sub 3}N{sub 5} semiconductor photocatalyst layers onto monodisperse spherical SiO{sub 2} particles. The obtained Ta{sub 3}N{sub 5}/SiO{sub 2} particles maintain an original spherical morphology of SiO{sub 2} and a sub-micrometer size with a narrow size distribution and without aggregation. The presence of SiO{sub 2} support shows at least no detrimental effects on photocatalytic activity, but tunes the secondary particle size to control dispersibility of the photocatalyst in the solution. - Highlights: • Fine nanoparticles of Ta{sub 3}N{sub 5} were immobilized on the surfaces of SiO{sub 2} giving SiO{sub 2}@Ta{sub 3}N{sub 5} core–shell spheres successfully produced H{sub 2} from methanol solution under visible light. • The presence of support (SiO{sub 2}) ensures the dispersion of the particulate in solution maintaining high photocatalytic activity of Ta{sub 3}N{sub 5}. • The obtained supported photocatalyst gives uniform size distribution and control the degree of dispersibility in the solution, which may control nature of light absorption and reflection of the photoreactor. - Abstract: Fine nanoparticles of Ta{sub 3}N{sub 5} (10–20 nm) were synthesized on the surfaces of SiO{sub 2} spheres with a diameter of ∼550 nm. A sol–gel method was used to modify the surface of SiO{sub 2} with Ta{sub 2}O{sub 5} from TaCl{sub 5} dissolved in ethanol in the presence of citric acid and polyethylene glycol. The resulting oxide composites were treated in an NH{sub 3} flow at 1123 K to form core–shell structured Ta{sub 3}N{sub 5}/SiO{sub 2} sub-microspheres. The obtained samples were characterized using powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectra (EDX), transmission electron microscopy (TEM), and

  18. Dynamic Fracture Toughness of TaC/CNTs/SiC CMCs Prepared by Spark Plasma Sintering

    Directory of Open Access Journals (Sweden)

    Qiaoyun Xie

    2015-01-01

    Full Text Available This study focuses on the fracture toughness of TaC and carbon nanotubes (CNTs reinforced SiC ceramic matrix composites (CMCs, prepared by spark plasma sintering (SPS technique. A high densification of 98.4% was achieved under the sintering parameter of 133°C/min, 1800°C, and 90 MPa pressure. Vickers indentation was employed to measure the indentation toughness on the polished surface of ceramic samples, SEM was applied to directly observe the crack propagation after indentation, and split Hopkinson pressure bar (SHPB was developed to determine the dynamic fracture toughness within the ceramic samples subjected to an impact in a three-point bending configuration.

  19. Alkane metathesis with the tantalum methylidene [(≡SiO)Ta(=CH2)Me2]/[(≡SiO)2Ta(=CH2)Me] generated from well-defined surface organometallic complex [(≡SiO)TaVMe4

    KAUST Repository

    Chen, Yin; Abou-Hamad, Edy; Hamieh, Ali Imad Ali; Hamzaoui, Bilel; Emsley, Lyndon; Basset, Jean-Marie

    2015-01-01

    By grafting TaMe5 on Aerosil700, a stable, well-defined, silica-supported tetramethyl tantalum(V) complex, [(≡SiO)TaMe4], is obtained on the silica surface. After thermal treatment at 150 °C, the complex is transformed into two surface tantalum methylidenes, [(≡SiO)2Ta(=CH2)Me] and [(≡SiO)Ta(=CH2)Me2], which are active in alkane metathesis and comparable to the previously reported [(≡SiO)2TaHx]. Here we present the first experimental study to isolate and identify a surface tantalum carbene as the intermediate in alkane metathesis. A systematic experimental study reveals a new reasonable pathway for this reaction.

  20. Alkane metathesis with the tantalum methylidene [(≡SiO)Ta(=CH2)Me2]/[(≡SiO)2Ta(=CH2)Me] generated from well-defined surface organometallic complex [(≡SiO)TaVMe4

    KAUST Repository

    Chen, Yin

    2015-01-21

    By grafting TaMe5 on Aerosil700, a stable, well-defined, silica-supported tetramethyl tantalum(V) complex, [(≡SiO)TaMe4], is obtained on the silica surface. After thermal treatment at 150 °C, the complex is transformed into two surface tantalum methylidenes, [(≡SiO)2Ta(=CH2)Me] and [(≡SiO)Ta(=CH2)Me2], which are active in alkane metathesis and comparable to the previously reported [(≡SiO)2TaHx]. Here we present the first experimental study to isolate and identify a surface tantalum carbene as the intermediate in alkane metathesis. A systematic experimental study reveals a new reasonable pathway for this reaction.

  1. Technical Area V (TA-V) transformation project close-out report.

    Energy Technology Data Exchange (ETDEWEB)

    2010-07-01

    Sandia National Laboratories (SNL) Technical Area V (TA-V) has provided unique nuclear experimental environments for decades. The technologies tested in TA-V facilities have furthered the United States Nuclear Weapons program and has contributed to the national energy and homeland security mission. The importance of TA-V working efficiently to produce an attractive and effective platform for experiments should not be underestimated. Throughout its brief history, TA-V has evolved to address multiple and diverse sets of requirements. These requirements evolved over many years; however, the requirements had not been managed nor communicated comprehensively or effectively. A series of programmatic findings over several years of external audits was evidence of this downfall. Today, these same requirements flow down through a new TA-V management system that produces consistently applied and reproducible approaches to work practices. In 2008, the TA-V department managers assessed the state of TA-V services and work activities to understand how to improve customer interfaces, stakeholders perceptions, and workforce efficiencies. The TA-V management team initiated the TA-V Transformation Project after they deemed the pre-June 2008 operational model to be ineffective in managing work and in providing integrated, continuous improvement to TA-V processes. This report summarizes the TA-V Transformation Project goals, activities, and accomplishments.

  2. Thermal stability of Cu/α-Ta/SiO2/Si structures

    International Nuclear Information System (INIS)

    Yuan, Z.L.; Zhang, D.H.; Li, C.Y.; Prasad, K.; Tan, C.M.

    2004-01-01

    The thermal stability of the Cu/α-Ta/SiO 2 /Si structures is investigated. Tantalum oxides are first observed at the interface between Cu and Ta due to residual oxygen in the annealing ambient at low annealing temperatures (about 600 deg. C). Ternary Cu-Ta oxides and/or Ta oxides rather than Cu oxides are found at the Cu top layer on account of the out diffusion of Ta. After high temperature annealing (up to 750 deg. C), polycrystalline Tantalum oxides (Ta 2 O 5 ) and Ta-rich silicides (Ta 5 Si 3 ) are found as dominant products due to the dissociation of SiO 2 . A severe intermixing of Cu, Ta and SiO 2 was observed after 800 deg. C annealing. First a drop and then an increase in sheet resistances were observed, the former possibly resulting from grain growth and impurities removal in Cu films, and the latter from the reduction of Cu thickness and formation of high resistivity products. The α-Ta films with a thickness of 25 nm have good barrier effectiveness up to 750 deg. C. The degradation of α-Ta film is mainly caused by self oxidation, silicidation and bidirectional diffusion

  3. Synthesis of low loss, thermally stable CexY1-xTiTaO6 microwave ceramics

    International Nuclear Information System (INIS)

    Padma Kumar, H.; John, Annamma; Vijayakumar, C.; Thomas, J.K.; Varma, Manoj Raama; Solomon, Sam

    2009-01-01

    Ce x Y 1-x TiTaO 6 ceramics were prepared through the solid-state ceramic route. The materials were sintered in the range 1520-1580 deg. C. The structure of the system was analyzed by X-ray diffraction and Raman spectroscopic methods. The cell parameters of solid solutions were calculated using the least square method. The microstructure was analyzed using scanning electron microscopy. The dielectric constant (ε r ), temperature coefficient of resonant frequency (τ f ) and the unloaded quality factor (Q u ) are measured in the microwave frequency region using cavity resonator method. The dielectric constant increases with higher concentrations of Ce in the solid solutions. Nearly zero temperature coefficient of resonant frequency (τ f ) was obtained for Ce 0.24 Y 0.76 TiTaO 6 . The samples are of high quality factor and are useful electronic materials for microwave applications

  4. Effect of annealing on the composition and structure of TiC and TaC powders

    International Nuclear Information System (INIS)

    Vavrda, J.; Blazhikova, J.

    1979-01-01

    Effect of annealing (1300-2000 deg C) upon lattice parameters and composition of TiC and TaC powders has been investigated. It is established that the lowest deviation from stoichiometric composition of TiC and TaC is the result of annealing the samples, placed in graphite crucibles, in the medium of pure argon. It is shown, that the processes of decarbonizing and crystal defect formation produce decisive effect upon recrystallization of titanium and tantalum carbides. Using the methods of X-ray diffraction and scanning electron microscopy significant difference is detected in structural changes in TiC at high temperature heat treatment compared to recrystallization processes in metals. Singled out are the following stages of the process: carbide decarbonizing and arizing of lattice distortions connected with it; progressing disorientation of mosaic blocks, connected with the increase in stresses of the second kind and subsequent gragmentation of big crystals; relief in fragmentated crystals

  5. Electronic parameters of Sr2M2O7 (M = V, Nb, Ta) and Sr-O chemical bonding

    DEFF Research Database (Denmark)

    Atuchin, Victor V.; Grivel, Jean-Claude; Zhang, Zhaoming

    2010-01-01

    XPS measurements were carried out on Sr2Nb2O7 and Sr2Ta2O7 powder samples, which were synthesized using standard solid state method. The binding energy differences between the O 1s and cation core level, Δ(O-Sr) = BE(O 1s) - BE(Sr 3d5/2), was used to characterize the valence electron transfer...... on the formation of the Sr-O bonds. The chemical bonding effects were considered on the basis of our XPS results for Sr2Nb2O7 and Sr2Ta2O7 and the previously published structural and XPS data for other Sr-oxide compounds. A new empirical relationship between Δ(O-Sr) and L(Sr-O) was obtained. Possible applications...

  6. High output power of differently cut Nd:MgO:LiTaO3 CW lasers

    Science.gov (United States)

    Sun, D. H.; Liu, S. D.; Wang, D. Z.; Sang, Y. H.; Kang, X. L.; Liu, H.; Bi, Y.; Yan, B. X.; He, J. L.; Wang, J. Y.

    2013-04-01

    A high-quality Nd3+ and Mg2+ co-doped LiTaO3 (Nd:MgO:LT) crystal was grown by the Czochralski method. The polarized absorption spectra and fluorescence spectra were studied, and the absorption cross section was calculated by Judd-Ofelt (J-O) theory. The laser performance with different sample cuts of the crystal was investigated for the first time, and it was found that Nd:MgO:LT crystal with different cutting directions (a and c) exhibits different laser properties. By optimizing a partial reflectivity mirror in the laser experimental setting, a high continuous wave output power of 3.58 W was obtained at 1092 and 1076 nm with an optical-to-optical conversion efficiency of 22.78% and slope efficiency of 26.06%. The results indicate that Nd:MgO:LT crystal is a promising candidate for the manufacture of Nd3+ doped periodically poled MgO:LiTaO3 crystal (Nd:PPMgOLT), which should have considerable applications in self-frequency doubling and optical parametric oscillation laser devices.

  7. High output power of differently cut Nd:MgO:LiTaO3 CW lasers

    International Nuclear Information System (INIS)

    Sun, D H; Liu, S D; Wang, D Z; Sang, Y H; Kang, X L; Liu, H; He, J L; Wang, J Y; Bi, Y; Yan, B X

    2013-01-01

    A high-quality Nd 3+ and Mg 2+ co-doped LiTaO 3 (Nd:MgO:LT) crystal was grown by the Czochralski method. The polarized absorption spectra and fluorescence spectra were studied, and the absorption cross section was calculated by Judd–Ofelt (J–O) theory. The laser performance with different sample cuts of the crystal was investigated for the first time, and it was found that Nd:MgO:LT crystal with different cutting directions (a and c) exhibits different laser properties. By optimizing a partial reflectivity mirror in the laser experimental setting, a high continuous wave output power of 3.58 W was obtained at 1092 and 1076 nm with an optical-to-optical conversion efficiency of 22.78% and slope efficiency of 26.06%. The results indicate that Nd:MgO:LT crystal is a promising candidate for the manufacture of Nd 3+ doped periodically poled MgO:LiTaO 3 crystal (Nd:PPMgOLT), which should have considerable applications in self-frequency doubling and optical parametric oscillation laser devices. (paper)

  8. Development of Ta-based Superconducting Tunnel Junction X-ray Detectors for Fluorescence XAS

    International Nuclear Information System (INIS)

    Friedrich, S.; Drury, O.; Hall, J.; Cantor, R.

    2009-01-01

    We are developing superconducting tunnel junction (STJ) soft X-ray detectors for chemical analysis of dilute samples by fluorescence-detected X-ray absorption spectroscopy (XAS). Our 36-pixel Nb-based STJ spectrometer covers a solid angle (Omega)/4π ∼ 10 -3 , offers an energy resolution of ∼10-20 eV FWHM for energies up to ∼1 keV, and can be operated at total count rates of ∼10 6 counts/s. For increased quantum efficiency and cleaner response function, we have now started the development of Ta-based STJ detector arrays. Initial devices modeled after our Nb-based STJs have an energy resolution below 10 eV FWHM for X-ray energies below 1 keV, and pulse rise time discrimination can be used to improve their response function for energies up to several keV. We discuss the performance of the Ta-STJs and outline steps towards the next-generation of large STJ detector arrays with higher sensitivity.

  9. Hot corrosion of Ti–46Al–8Ta (at.%) intermetallic alloy

    International Nuclear Information System (INIS)

    Godlewska, E.; Mitoraj, M.; Leszczynska, K.

    2014-01-01

    Highlights: •Cyclic oxidation tests with salt deposits were conducted on Ti–46Al–8Ta (at.%) alloy. •Mineral contaminants had detrimental effect on oxidation resistance. •Sodium chloride appeared to be the most hazardous among salts used. •Significant material losses were attributed to self-sustaining reaction mechanism. -- Abstract: Hot corrosion behaviour of a fully lamellar Ti–46Al–8Ta (at.%) alloy was studied in air under thermal cycling conditions (20-h cycles) at 700 and 800 °C. The samples were purposely contaminated with salt deposits consisting of NaCl or Na 2 SO 4 or a mixture of these. The progress of degradation was followed by mass change measurements and visual inspection. Post-exposure examination involved scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The composition of salt deposits clearly influenced the rate and type of corrosion. Sodium chloride appeared especially harmful because of the formation of volatile chloride species

  10. Radionuclide contaminant analysis of small mammals at Area G, TA-54, 1994

    International Nuclear Information System (INIS)

    Biggs, J.; Bennett, K.; Fresquez, P.

    1995-09-01

    Small mammals were sampled at two waste burial sites (1 and 2) at Area G, TA-54 and a control site outside Area G (Site 3) to identify radionuclides that are present within surface and subsurface soils at waste burial sites, to compare the amount of radionuclide uptake by small mammals at waste burial sites to a control site, and to identify the primary mode of contamination to small mammals, either through surface contact or ingestion/inhalation. Three composite samples of at least five animals per sample were collected at each site. Pelts and carcasses of each animal were separated and analyzed independently. Samples were analyzed for 241 Am, 90 Sr, 238 Pu, 239 Pu, total U, and gamma spectroscopy (including 137 Cs). Significantly higher (parametric t-test at p = 0.05) levels of total U, 241 Am, 238 Pu, 239 Pu, and 40 K were detected in pelts as compared to the carcasses of small mammals at TA-54. Concentrations of other measured radionuclides in carcasses were nearly equal to or exceeded the mean concentrations in the pelts. The authors results show higher concentrations in pelts compared to carcasses which is similar to what has been found at waste burial/contaminated sites outside of Los Alamos National Laboratory. Site 1 had significantly higher (alpha = 0.05, F = 0.0095) total U concentrations in carcasses than Sites 2 and 3. Site 2 had significantly higher (alpha = 0.05, F = 0.0195) 239 Pu concentrations in carcasses than either Site 1 or Site 3. A significant difference in 90 Sr concentration existed between Sites 1 and 2 (alpha = 0.05, F = 0.0681) and concentrations of 40 K at Site 1 were significantly different from Site 3

  11. Concentration and temperature dependence of short-range order in Ni-Ta solid solution using X-ray diffraction method

    International Nuclear Information System (INIS)

    Khwaja, F.A.; Alam, A.

    1980-09-01

    Diffuse X-ray scattering investigations about the existence of short-range order (SRO) have been carried out in the Ni-Ta system for different concentrations and annealing temperatures. It is observed that the values of the SRO parameters for the first co-ordination shell have anomalously large negative values for all the samples studied. These values of the α 1 depend upon the annealing temperatures and the concentration of Ta atoms in the Ni-Ta system. The results of the theoretical predictions of the ordering potential obtained using the formulae of the electronic theory of SRO, confirm the existence of very strong attractive correlation between the atoms of the different species in this system. (author)

  12. Anti-Ma2/Ta antibodies in a woman with primary lateral sclerosis-like phenotype and Sjögren syndrome.

    Science.gov (United States)

    Piccolo, Giovanni; Tavazzi, Eleonora; Jarius, Sven; Alfonsi, Enrico; Cavagna, Lorenzo; Piccolo, Laura; Zardini, Elisabetta; Voltz, Raymond; Franciotta, Diego

    2011-10-01

    Anti-Ma2/Ta antibodies are rare paraneoplastic antibodies, which are mostly associated with limbic encephalitis in male patients with testicular cancer. We report on a 50-year-old woman with a pure progressive spastic paraparesis. Next, she was diagnosed as having a Sjögren syndrome, with serological positivity for anti-SS-Ro antibodies. The patient's serum and cerebrospinal fluid samples were positive for anti-Ma2/Ta antibodies, which were also proved to be intrathecally produced. These findings, and the coexistence of systemic autoimmunity, led us to treat the patient with corticosteroids first, and then with plasma exchange. Neurological symptoms scarcely responded to both the therapies. The search for cancer was negative up to 4 years after the disease onset. Our case expands the spectrum of clinical syndromes associated with anti-Ma2/Ta antibodies.

  13. Facile and efficient synthesis of the surface tantalum hydride (≡SiO)2TaIIIH and tris-siloxy tantalum (≡SiO)3TaIII starting from novel tantalum surface species (≡SiO)TaMe4 and (≡SiO)2TaMe 3

    KAUST Repository

    Chen, Yin

    2014-03-10

    By grafting of TaMe5 (1) on the surface of silica partially dehydroxylated at 500 C (silica500), a mixture of (≡SiO)TaMe4 (2a; major, 65 ± 5%) and (≡SiO) 2TaMe3 (2b; minor, 35 ± 5%) was produced, which has been characterized by microanalysis, IR, and SS NMR (1H, 13C, 1H-13C HETCOR, proton double and triple quantum). After grafting, these surface organometallic compounds are more stable than the precursor TaMe5. Treatment of 2a,b with water and H 2 resulted in the formation of methane in amount of 3.6 ± 0.2 and 3.4 ± 0.2 mol/grafted Ta, respectively. 2a,b react with H2 (800 mbar) to form (≡SiO)2TaH. After (≡SiO) 2TaH was heated to 500 C under hydrogen or vacuum, [(≡SiO) 3Ta][≡SiH] was produced, and the structure was confirmed by IR, NMR, and EXAFS. Considering the difficulty of the previous preparation method, these syntheses represent a facile and convenient way to prepare tantalum surface species (≡SiO)2TaH and (≡SiO)3Ta via the intermediate of the new surface organometallic precursors: (≡SiO)TaMe4/(≡SiO)2TaMe3. (≡SiO)2TaH and (≡SiO)3Ta exhibit equal reactivities in alkane metathesis and ethylene polymerization in comparison to those in previous reports. © 2014 American Chemical Society.

  14. Facile and efficient synthesis of the surface tantalum hydride (≡SiO)2TaIIIH and tris-siloxy tantalum (≡SiO)3TaIII starting from novel tantalum surface species (≡SiO)TaMe4 and (≡SiO)2TaMe 3

    KAUST Repository

    Chen, Yin; Ould-Chikh, Samy; Abou-Hamad, Edy; Callens, Emmanuel; Mohandas, Janet Chakkamadathil; Khalid, Syed M.; Basset, Jean-Marie

    2014-01-01

    By grafting of TaMe5 (1) on the surface of silica partially dehydroxylated at 500 C (silica500), a mixture of (≡SiO)TaMe4 (2a; major, 65 ± 5%) and (≡SiO) 2TaMe3 (2b; minor, 35 ± 5%) was produced, which has been characterized by microanalysis, IR, and SS NMR (1H, 13C, 1H-13C HETCOR, proton double and triple quantum). After grafting, these surface organometallic compounds are more stable than the precursor TaMe5. Treatment of 2a,b with water and H 2 resulted in the formation of methane in amount of 3.6 ± 0.2 and 3.4 ± 0.2 mol/grafted Ta, respectively. 2a,b react with H2 (800 mbar) to form (≡SiO)2TaH. After (≡SiO) 2TaH was heated to 500 C under hydrogen or vacuum, [(≡SiO) 3Ta][≡SiH] was produced, and the structure was confirmed by IR, NMR, and EXAFS. Considering the difficulty of the previous preparation method, these syntheses represent a facile and convenient way to prepare tantalum surface species (≡SiO)2TaH and (≡SiO)3Ta via the intermediate of the new surface organometallic precursors: (≡SiO)TaMe4/(≡SiO)2TaMe3. (≡SiO)2TaH and (≡SiO)3Ta exhibit equal reactivities in alkane metathesis and ethylene polymerization in comparison to those in previous reports. © 2014 American Chemical Society.

  15. Atomic resolution investigations of phase transformation from TaN to CrTaN in a steel matrix

    DEFF Research Database (Denmark)

    Danielsen, Hilmar Kjartansson; Hald, John

    2012-01-01

    strength of the steel. The Cr content promotes Z-phase precipitation, making MN strengthening of these materials unfeasible, since 12%Cr is necessary for oxidation resistance. The authors have suggested an acceleration of Z-phase precipitation to obtain a fine and stable distribution of CrMN instead of MN...... atoms diffuse from the steel matrix into TaN precipitates and physically transform them into CrTaN. The crystal structure of the precipitates changes from that of a typical MN NaCl type crystal structure to a Z-phase crystal structure with alternating double layers of Cr and TaN. Since there is a large......In development of 12%Cr high temperature steels used for fossil fired power plants, the precipitation of large Z-phase particles, CrMN, has been identified as a major problem since they replace small and finely distributed MN particles. This causes a premature breakdown in the longterm creep...

  16. The modification of LiTaO3 crystal by low-energy He-ion implantation

    International Nuclear Information System (INIS)

    Pang, L.L.; Wang, Z.G.; Jin, Y.F.; Yao, C.F.; Cui, M.H.; Sun, J.R.; Shen, T.L.; Wei, K.F.; Zhu, Y.B.; Sheng, Y.B.; Li, Y.F.

    2012-01-01

    Highlights: ► LiTaO 3 crystal was implanted by 250 keV He + . ► We report the surface and transmittance of LiTaO 3 change with the fluence and time. ► New phenomena (self-splitting, self-exfoliation, self-recovery) occurred. ► Evolvement of defects and the behavior of helium were discussed. - Abstract: The effects of He-ion implantation on the surface morphology and transmittance of LiTaO 3 single crystals are investigated. The samples were implanted with 250 keV He-ion at different fluences at room temperature. The results show that the surface morphology and transmittance of implanted samples strongly depend on the ion fluence and the time when the samples expose to the air up to 60 days. When the fluence is above 1.0 × 10 16 He + /cm 2 , the transmission spectra indicate that a high concentration of defects is created. 3D-profile images show that at the higher fluence a great many triangular stripes appear on the surface of the samples. After 60 days, the recovery of the transmittance occurs and varies with the fluence. For the sample at the fluence of 5.0 × 10 16 He + /cm 2 , the raised stripes on the surface evolve into narrow cracks. Regional exfoliation, however, occurs on the surface of the sample with the fluence of 1.0 × 10 17 He + /cm 2 . According to the experimental results and simulation of SRIM 2008 code, the evolvement of defects and the behavior of He are discussed.

  17. Effects of thickness and annealing condition on magnetic properties and thermal stabilities of Ta/Nd/NdFeB/Nd/Ta sandwiched films

    International Nuclear Information System (INIS)

    Liu Wen-Feng; Zhang Min-Gang; Zhang Ke-Wei; Zhang Hai-Jie; Chai Yue-Sheng; Xu Xiao-Hong

    2016-01-01

    Ta/Nd/NdFeB/Nd/Ta sandwiched films are deposited by magnetron sputtering on Si (100) substrates, and subsequently annealed in vacuum at different temperatures for different time. It is found that both the thickness of NdFeB and Nd layer and the annealing condition can affect the magnetic properties of Ta/Nd/NdFeB/Nd/Ta films. Interestingly, the thickness and annealing temperature show the relevant behaviors that can affect the magnetic properties of the film. The high coercivity of 24.1 kOe (1 Oe = 79.5775 A/m) and remanence ratio (remanent magnetization/saturation magnetization) of 0.94 can be obtained in a Ta/Nd(250 nm)/NdFeB(600 nm)/Nd(250 nm)/Ta film annealed for 3 min at 1023 K. In addition, the thermal stability of the film is also linked to the thickness of NdFeB and Nd layer and the annealing temperature as well. The excellent thermal stability can be achieved in a Ta/Nd(250 nm)/NdFeB(600 nm)/Nd(250 nm)/Ta film annealed at 1023 K. (paper)

  18. Thin TiOx layer as a voltage divider layer located at the quasi-Ohmic junction in the Pt/Ta2O5/Ta resistance switching memory.

    Science.gov (United States)

    Li, Xiang Yuan; Shao, Xing Long; Wang, Yi Chuan; Jiang, Hao; Hwang, Cheol Seong; Zhao, Jin Shi

    2017-02-09

    Ta 2 O 5 has been an appealing contender for the resistance switching random access memory (ReRAM). The resistance switching (RS) in this material is induced by the repeated formation and rupture of the conducting filaments (CFs) in the oxide layer, which are accompanied by the almost inevitable randomness of the switching parameters. In this work, a 1 to 2 nm-thick Ti layer was deposited on the 10 nm-thick Ta 2 O 5 RS layer, which greatly improved the RS performances, including the much-improved switching uniformity. The Ti metal layer was naturally oxidized to TiO x (x resistance value was comparable to the on-state resistance of the Ta 2 O 5 RS layer. The series resistor TiO x efficiently suppressed the adverse effects of the voltage (or current) overshooting at the moment of switching by the appropriate voltage partake effect, which increased the controllability of the CF formation and rupture. The switching cycle endurance was increased by two orders of magnitude even during the severe current-voltage sweep tests compared with the samples without the thin TiO x layer. The Ti deposition did not induce any significant overhead to the fabrication process, making the process highly promising for the mass production of a reliable ReRAM.

  19. Studies on layer growth and interfaces on Ta-base thin layers by means of XPS

    International Nuclear Information System (INIS)

    Zier, M.

    2007-01-01

    In this thesis studies on the growth and on the formation of the interfaces of Ta and TaN layers on Si and SiO 2 were performed. In the system TaN on SiO 2 no reaction on the interface could be found. As the system with the mostly disturbed interface Ta on SiO 2 was proved. Here a reduction of the SiO 2 at simultaneous oxidation of the Ta was to be observed. Additionally tantalum silicide was formed to be considered concerning the bonding state as Ta 5 Si 3 , from which a double layer of a tantalum silicide and a tantalum suboxide resulted. A whole thickness of the double layer of above 1 nm resulted. In the system Ta on Si at the deposition of the film on the interface a tantalum silicide was formed to be characterized concerning the bonding state as TaSi 2 . The thickness of the interlayer growed thereby up to 0.8 nm in form of islands. Finally in the system TaN on Si a silicon nitride formation during the deposition was observed, which was attributed to the insertion of adsorbed nitrogen from the sputtering atmosphere by recoil implantation of the sputtered Ta atoms. The silicon nitride interlayer growed thereby up to a thickness of 0.8 nm

  20. Electric conductivity of salt melts containing KCL, KF and K2TaF7

    International Nuclear Information System (INIS)

    Agulyanskij, A.I.; Stangrit, P.T.; Konstantinov, V.I.

    1978-01-01

    Given are electric conductivity measurement results depending on the temperature and composition of the molten KF-K 2 TaF 7 , KCl-K 2 TaF 7 systems and also melts close in their composition to industrial electrolytes, KCl-KF (in mass ratio of 2:1) with addition of K 2 TaF 7 up to 25 mass%. Presented are electric conductivity molecular isotherms of the KF-K 2 TaF 7 , KCl-K 2 TaF 7 systems at 800 deg C and specific electric conductivity dependence of KCl-KF-K 2 TaF 7 melts on K 2 TaF 7 composition at 800 deg C and 900 deg C. Proceeding from the shape of molecular and specific electric conductivity isotherms a conclusion is made about existence of the following tantalum-containing ions: TaF 7 2- , TaF 6 - and TaF 6 Cl 2- in the investigated melts

  1. Structural, mechanical, and electronic properties of TaB2, TaB, IrB2, and IrB: First-principle calculations

    International Nuclear Information System (INIS)

    Zhao Wenjie; Wang Yuanxu

    2009-01-01

    First-principle calculations were performed to investigate the structural, elastic, and electronic properties of TaB 2 , TaB, IrB 2 , and IrB. The calculated equilibrium structural parameters, shear modulus, and Young's modulus of TaB 2 are well consistent with the available experimental data, and TaB 2 with P6/mmm space group has stronger directional bonding between ions than WB 2 , OsB 2 , IrN 2 , and PtN 2 . For TaB 2 , the hexagonal P6/mmm structure is more stable than the orthorhombic Pmmn one, while for IrB 2 the orthorhombic Pmmn structure is the most stable one. The high shear modulus of P6/mmm phase TaB 2 is mainly due to the strong covalent π-bonding of B-hexagon in the (0001) plane. Such a B-hexagon network can strongly resist against an applied [112-bar0] (0001) shear deformation. Correlation between the hardness and the elastic constants of TaB 2 was discussed. The band structure shows that P6/mmm phase TaB 2 and Pmmn phase IrB 2 are both metallic. The calculations show that both TaB and IrB are elastically stable with the hexagonal P6 3 /mmc structure. - Elastic constant c 44 of TaB 2 is calculated to be 235 GPa. This value is exceptionally high, exceeding those of WB 2 , OsB 2 , WB 4 , OsN 2 , IrN 2 , and PtN 2 .

  2. Phase diagrams for pseudo-binary carbide systems TiC-NbC, TiC-TaC, ZrC-NbC, ZrC-TaC and HfC-TaC

    International Nuclear Information System (INIS)

    Gusev, A.I.

    1985-01-01

    Parameters of interaction and energy of mutual exchange in the liquid and solid phases of pseudobinary TiC-NbC, TiC-TaC, ZrC-NbC, ZrC-TaC, HfC-TaC systems are calculated with account of dependence on composition and temperature. Positions of liquidus-solidus phase boundaries on the phase diagrams of the mentioned systems are calculated on the basis of the determined mutual exchange energies in approximati.on of subregular solutions. The existance of latent decomposition ranges in the solid phase on the phase diagrams of the investgated systems is established

  3. TA-54 (Area G) Risk Assessment from Extreme Wildfire Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Linn, Rodman Ray [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Koo, Eunmo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Honig, Kristen Ann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); White, Judith [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Funk, David John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-10

    Los Alamos National Laboratory (LANL) and surrounding areas have been exposed to at least four significant wildfires since 1977 and there have been numerous others within 50 miles of LANL. Based on this history, wildfires are considered a risk to LANL facilities and their contents. While many LANL facilities are at risk to wildfire to some degree, they are found in a wide variety of conditions, thus they have varying sensitivities to wildfires. Additionally, LANL facilities have various functions and different assets, so they have a wide range of values or consequences if compromised. Therefore, determining the risks and precautions that are warranted to mitigate these risks must be done on a case-by-case basis. In an effort to assess possible wildfire risks to sensitive materials stored in a Perma-Con® in dome TA-54-0375, a conventional fire risk analysis was performed. This conventional risk analysis is documented in Engineering Evaluation Form AP-FIRE-001-FM1, which is dated 9/28/2015 and was titled ‘Wildland Fire Exposure Evaluation for Building TA-54-0375’ (Hall 2015). This analysis acknowledged that there was significant chance of wildfire in the vicinity of TA-54-0375, but the amount of combustible material surrounding the building was deemed low. The wildland fuels that were closest to the building were largely fine fuels and were not expected to have significant duration of heat release. The prevailing winds at this location are from the south and southwest and the nearest significant upwind fuels (tree crowns or unmown grasses) are at least 300 feet away. Based on these factors the conventional wildland fire risk to TA-54-0375 was deemed minimal, “Acceptable As Is, No Action Required.” This risk evaluation was based on a combined assessment of low probability of wildfires arriving at the site from other directions (where higher fuel loadings might be present) as well as the effective setback of fuels in the direction that fire is

  4. Nucleation of fcc Ta when heating thin films

    International Nuclear Information System (INIS)

    Janish, Matthew T.; Mook, William M.; Carter, C. Barry

    2015-01-01

    Thin tantalum films have been studied during in situ heating in a transmission electron microscope. Diffraction patterns from the as-deposited films were typical of amorphous materials. Crystalline grains were observed to form when the specimen was annealed in situ at 450 °C. Particular attention was addressed to the formation and growth of grains with the face-centered cubic (fcc) crystal structure. These observations are discussed in relation to prior work on the formation of fcc Ta by deformation and during thin film deposition

  5. Critical behaviour in very pure Ni-Ta systems

    International Nuclear Information System (INIS)

    Oddou, J.L.; Berthier, J.; Peretto, P.

    1978-01-01

    The authors use the perturbed angular correlation technique to follow the behaviour of the magnetic hyperfine field on 181 Ta in nickel in the critical region of the matrix. Contrary to what is expected, it is observed that the critical exponent associated to the hyperfine field is different from the critical exponent associated to the bulk magnetization. Because the concentrations of the various impurities are very low, the authors think that the explanation of the phenomenon is to be found in the framework of a one-impurity model interacting with the surrounding spins via an isotropic exchange energy

  6. Symposium in Honour of T.A. Springer

    CERN Document Server

    Hesselink, Wim; Kallen, Wilberd; Strooker, Jan

    1987-01-01

    From 1-4 April 1986 a Symposium on Algebraic Groups was held at the University of Utrecht, The Netherlands, in celebration of the 350th birthday of the University and the 60th of T.A. Springer. Recognized leaders in the field of algebraic groups and related areas gave lectures which covered wide and central areas of mathematics. Though the fourteen papers in this volume are mostly original research contributions, some survey articles are included. Centering on the Symposium subject, such diverse topics are covered as Discrete Subgroups of Lie Groups, Invariant Theory, D-modules, Lie Algebras, Special Functions, Group Actions on Varieties.

  7. TaC Studios New Construction Test House

    Energy Technology Data Exchange (ETDEWEB)

    Butler, T. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Curtis, O. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Kim, E. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Roberts, S. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Stephenson, R. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States)

    2013-03-01

    As part of the NAHB Research Center Industry Partnership, Southface partnered with TaC Studios, an Atlanta based architecture firm specializing in residential and light commercial design, on the construction of a new test home in Atlanta, GA, in the mixed humid climate zone. This home will serve as a model home for the builder partner and addresses Building America energy savings targets through the planning and implementation of a design package will serve as a basis of design for the builder partner’s future homes. As a BA test house, this home will be evaluated to detail whole house energy use, end use loads, and HVAC and hot water efficiency.

  8. Role of Ta-spacer layer on tuning the tilt angle magnetic anisotropy of L1{sub 1}-CoPt/Ta/NiFe exchange springs

    Energy Technology Data Exchange (ETDEWEB)

    Saravanan, P., E-mail: psdrdo@gmail.com [Defence Metallurgical Research Laboratory, Hyderabad 500058 (India); Talapatra, A.; Mohanty, J. [Department of Physics, Indian Institute of Technology Hyderabad, Hyderabad 502285 (India); Hsu, Jen-Hwa, E-mail: jhhsu@phys.ntu.edu.tw [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Kamat, S.V. [Defence Metallurgical Research Laboratory, Hyderabad 500058 (India)

    2017-06-15

    Highlights: • Role of Ta-spacer layer in L1{sub 1}-CoPt(10 nm)/Ta//NiFe(4 nm) trilayers was investigated. • Domain size increased at the expense of magnetic phase contrast with increasing t{sub Ta}. • Tilt angle magnetization increased from 43° to 77° upon increasing t{sub Ta} (0–2.5 nm). • Micromagnetic studies confirmed the existence of tilted magnetic anisotropy. • Ta-spacer is effective in preserving competing anisotropies of CoPt and NiFe-layers. - Abstract: L1{sub 1}-CoPt/Ta/NiFe trilayers are chosen as model films for probing the role of spacer layer on tuning the tilt angle magnetization (θ{sub M}) in such exchange springs. For this purpose, a non-magnetic layer (Ta) with varying thickness (t{sub Ta}) from 0 to 2.5 nm was inserted between 10-nm thick CoPt film exhibiting strong perpendicular magnetic anisotropy (PMA) and 4-nm thick NiFe film having in-plane magnetic anisotropy (IMA). With the insertion of Ta-spacer, the magnetic hysteresis loops become more and more tilted as t{sub Ta} increases. Upon increasing the t{sub Ta} from 0 to 2.5 nm, the estimated SQR{sub ⊥} (=M{sub r⊥}/M{sub s⊥}) from the M–H loops is found to decrease moderately; while the θ{sub M} increases significantly from 43° to 77°. MFM images revealed maze-like domain patterns and the domain size tends to increase at the expense of magnetic phase contrast with increasing t{sub Ta}. Micro-magnetic simulation of tilt in the anisotropy axis with respect to the bare CoPt-layer showed a trend similar to that of those observed with the M–H loops obtained by VSM measurements. The results of present study suggest that the insertion of Ta-spacer is not only beneficial in terms of preserving the competing anisotropies such as PMA and IMA of CoPt and NiFe-layers respectively through weakened exchange coupling; but also, act as an appropriate means for realizing tunable tilted magnetic anisotropy in the L1{sub 1}-CoPt/NiFe exchange springs.

  9. Stress effect on the critical current of Ti-Nb-Zr-Ta multifilamentary superconductors

    International Nuclear Information System (INIS)

    Monju, Yoshiyuki; Tatara, Isamu

    1978-01-01

    The tensile behaviour at R.T., 77K, 4.2K and the degradation of the critical current with stress have been measured on multifilamentary Ti-Nb-Zr-Ta alloy superconductors. The assembly of the stress effect apparatus is as follows; At the center of the 60KOe superconducting solenoid coil, sample wire is hold around an FRP spool and the wire ends are gripped to the load train. Current is supplied through helium vapourcooled flexible leads up to 2000 A. It was clear that a definite degradation of the critical current with stress was not observed up to the stress equal to one third of the fracture stress at 4.2K. This stress value should be defined the maximum allowable stress of alloy superconductors examined from stress effects. (author)

  10. Release Report for Building Debris for TA-21 Sewage Treatment Facility

    Energy Technology Data Exchange (ETDEWEB)

    Whicker, Jeffrey Jay [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gillis, Jessica [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ruedig, Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-03

    ENV-ES finds that the materials associated with TA-21 Buildings 227 (superstructure only), and 229 (see Figure 1) meet the criteria for unrestricted release to the public for recycle or as sanitary/commercial waste. The interior and exterior of the metal shed, building 387, passed the release criteria collectively; however, results from the roof of the structure were above reference background measurements. Waste management should be consulted for waste disposition options for the roofing metal. These findings are consistent with the requirements of DOE Order 458.1 “Radiation Protection of the Public and the Environment” and LANL Policy 412 “Environmental Radiation Protection.” Sampling and data analysis, as described in this report, were sufficient to meet measurement objectives under the Multi-Agency Radiation Survey and Assessment of Materials and Equipment (MARSAME) manual (2009).

  11. Ultrafast Doublon Dynamics in Photoexcited 1 T -TaS2

    Science.gov (United States)

    Ligges, M.; Avigo, I.; Golež, D.; Strand, H. U. R.; Beyazit, Y.; Hanff, K.; Diekmann, F.; Stojchevska, L.; Kalläne, M.; Zhou, P.; Rossnagel, K.; Eckstein, M.; Werner, P.; Bovensiepen, U.

    2018-04-01

    Strongly correlated materials exhibit intriguing properties caused by intertwined microscopic interactions that are hard to disentangle in equilibrium. Employing nonequilibrium time-resolved photoemission spectroscopy on the quasi-two-dimensional transition-metal dichalcogenide 1 T -Ta S2 , we identify a spectroscopic signature of doubly occupied sites (doublons) that reflects fundamental Mott physics. Doublon-hole recombination is estimated to occur on timescales of electronic hopping ℏ/J ≈14 fs . Despite strong electron-phonon coupling, the dynamics can be explained by purely electronic effects captured by the single-band Hubbard model under the assumption of weak hole doping, in agreement with our static sample characterization. This sensitive interplay of static doping and vicinity to the metal-insulator transition suggests a way to modify doublon relaxation on the few-femtosecond timescale.

  12. The transabdominal chorionic villus sampling puncture guided by color Doppler ultrasound during early pregnancy

    International Nuclear Information System (INIS)

    Liang Weixiang; Chen Zhiyi; Yuan Wenlin; Cai Kuan; Zhu Junlin; Wang Weiqun; Chen Xia

    2008-01-01

    Objective: To study the operation of chorionic villus sampling (CVS) guided by color Doppler ultrasound (CDU) via abdomen puncture during early pregnancy and investigate the advertences during the operation. Methods: CVS guided by CDU probe via abdomen puncture were operated on 28 pregnant women who had the indications of antenatal diagnosis. CDU was used to observe the implantation position of the fo1iaceous villis and help setting mark of the puncture point and puncture range on body surface before operation. The needle was punctured under real-time ultrasound guidance and villis were aspirated during the operation: The choice of the right time of puncture and the operation skills were emphasized in the study. Results: The CVS puncture approach should be set through CDU ob servation, which attend to avoid the surrounding blood vessels, intestinal canal and surrounding important organs. The puncture point should be chosen in a point where lobif0rmed villis distributed wider and with a larger scope. The operations were performed from 10 to13 weeks of pregnancy, with an average of 11 weeks. Among these 28 cases, 9.6 were successfully drawn materials in one time, 1 in twice and l failure, with the total ratio of achievement was 96.4%. For all the cases, fetal heart pulsating could be seen by real-time CDU observation fight after the operation, and no larger hematoma echo in the placental site occurred. Ultrasound reexamined one week after the operation, fetal heart pulsation could be found in all cases, and no abortion cases occurred after regular follow-up in 25 continued pregnant patients. Conclusion: Abdominal CVS puncture guided by CDU probe is conveniently operated, safe and available in clinic. It is an important method for antenatal diagnosis during early pregnancy. The puncture localization, skills and the time are the key points for the success in obtaining the materials. (authors)

  13. Influence of lead oxide addition on LnTiTaO6 (Ln = Ce, Pr and Nd) microwave ceramics

    International Nuclear Information System (INIS)

    Padma Kumar, H.; Thomas, J.K.; John, Annamma; Solomon, Sam

    2011-01-01

    The effect of PbO addition on the structural, processing and microwave dielectric properties of LnTiTaO 6 (Ln = Ce, Pr and Nd) ceramics are reported. Conventional solid state ceramic route was used for the preparation of samples. Phase pure LnTiTaO 6 (Ln = Ce, Pr and Nd) ceramics are prepared at a calcination temperature of 1300 deg C. The samples are sintered at optimized temperatures. Addition of PbO reduces the sintering temperature. The crystal structure of the materials was analysed using X-ray diffraction techniques and the surface morphology of the sintered samples was analysed using scanning electron microscopy. The dielectric constant at microwave frequency range decreases for higher PbO addition for all the samples but the quality factor improves on small PbO addition. The thermal stability of resonant frequency was also improved with PbO addition on all the systems. A number of samples with improved microwave dielectric properties were obtained on all the systems suitable for practical applications. (author)

  14. Study on mutual diffusion and phase diagram in the Ni-Ta system

    International Nuclear Information System (INIS)

    Pimenov, V.N.; Ugaste, Yu.Eh.; Akkushkarova, K.A.

    1977-01-01

    The mutual diffusion in the Ni-Ta system has been investigated with a view of refining the constitutional diagram. The mutual diffusion factors and their effective values in the various phases and the diffusion activation energies are calculated. Given are the dependences of the phase growth constants and the mutual diffusion factors upon the temperature. The existence of five new phases Ta 2 Ni, TaNi, TaNi 2 , TaNi 3 , TaNi 8 has been discovered in the range of temperatures between 1150 and 1300 deg C. It is established that all the phases have a small concentration range of existence. It is noted that the diffusion characteristics in the phases (mutual diffusion factor and activation energy) differ widely, but fail to correlate with their melting points

  15. Carrier dynamics of a visible-light-responsive Ta3N5 photoanode for water oxidation

    KAUST Repository

    Ziani, Ahmed; Nurlaela, Ela; Dhawale, Dattatray Sadashiv; Silva, Diego Alves; Alarousu, Erkki; Mohammed, Omar F.; Takanabe, Kazuhiro

    2015-01-01

    The physicochemical properties of a tantalum nitride (Ta3N5) photoanode were investigated in detail to understand the fundamental aspects associated with the photoelectrochemical (PEC) water oxidation. The Ta3N5 thin films were synthesized using DC magnetron sputtering followed by annealing in air and nitridation under ammonia (NH3). A polycrystalline structure with a dense morphology of the monoclinic Ta3N5 films was obtained. A relatively low absorption coefficient (104 to 105 cm-1) in the visible light range was measured for Ta3N5, consistent with the nature of the indirect band-gap. Ultra-fast spectroscopic measurements revealed that the Ta3N5 with different thicknesses films possess low transport properties and fast carrier recombination (<10 ps). These critical kinetic properties of Ta3N5 as a photoanode may necessitate high overpotentials to achieve appreciable photocurrents for water oxidation (onset ∼0.6 V vs. RHE). This journal is

  16. Low emissivity Ag/Ta/glass multilayer thin films deposited by sputtering

    International Nuclear Information System (INIS)

    Park, Sun Ho; Lee, Kee Sun; Sivasankar Reddy, A.

    2011-01-01

    Ta is deposited on a glass substrate as an interlayer for the two-dimensional growth of Ag thin films because Ta has good thermal stability and can induce a negative surface-energy change in Ag/glass. From the transmission electron microscopy results, we concluded that the Ag crystals in the bottom layer (seemingly on Ag/Ta) were flattened; this was rarely observed in the three-dimensional growth mode. Comparing Ag/Ta/glass with Ag/glass, we found that the Ta interlayer was effective in reducing both the resistance and the emissivity, accompanied by the relatively high transmittance in the visible region. In particular, Ag(9 nm)/Ta(1 nm)/glass film showed 0.08 of the emissivity, including ∼61% of the transmittance in the visible region (wavelength: 550 nm).

  17. Effect of Ni interlayer on diffusion bonding of a W alloy and a Ta alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jian; Liu, Ruxia; Wei, Qinqin; Luo, Guoqiang; Shen, Qiang; Zhang, Lianmeng [Wuhan Univ. of Technology (China). The State Key Lab. of Advanced Technology for Materials Synthesis and Processing

    2017-11-01

    The combination of W and Ta is expected to be highly beneficial for many applications from aerospace, weapons, military and nuclear industry. In this paper, W and Ta alloys were successfully diffusion bonded with Ni interlayer. The process of the formation of W/Ni/Ta diffusion bonded joints was investigated by means of scanning electron microscopy, X-ray diffraction system, electron probe micro-analyzer, energy dispersive spectrometry and shear strength measurement. The results show that the shear strength increases when the bonding temperature increases and exhibits a maximum value of 244 MPa at 930 C. The bonding of W/Ni can be attributed to the bonding of Ni to tungsten grains and the bonding of Ni to a Ni-Fe-binder mainly by elemental diffusion. The fracture takes place in the Ni/Ta interface and Ni{sub 3}Ta and Ni{sub 2}Ta intermetallic compounds are formed on the fracture surfaces.

  18. New levels of Ta II with energies higher than 72,000 cm−1

    International Nuclear Information System (INIS)

    Uddin, Zaheer; Windholz, Laurentius

    2014-01-01

    We studied the hyperfine structure of Tantalum lines appearing in a high-resolution Fourier transform spectrum. Hundreds of lines of Ta in this spectrum are still unclassified; most of them, especially in the UV region, belong to Ta II. When investigating such lines we found 14 new levels of Ta II. These new levels are the highest-lying known Ta II levels and do not belong to the already known configurations. - Highlights: • We report the discovery of 14 even energy levels of the first ion of Tantalum (Ta II). • Their energy ranges from 72,000 to 81,000 cm −1 . • For comparison, up to now only even levels between 0 and 44,000 cm −1 were known. • These levels belong to up to now unknown electron configurations. • With help of these levels, approximately 100 spectral lines of Ta II can be classified

  19. Experimental investigation of phase equilibria in the Nb-Si-Ta ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jian; Wang, Cuiping; Yao, Jun; Yang, Shuiyuan; Zhan Shi; Liu, Xingjun [Xiamen Univ. (China). Dept. of Materials Science and Engineering; Xiamen Univ. (China). Fujian Provincial Key Laboratory of Materials Genome; Kang, Yongwang [Beijing Institute of Aeronautical Materials (China). Science and Technology on Advanced High Temperature Structural Materials Lab.

    2016-12-15

    The phase equilibria in the Nb-Si-Ta ternary system at 1 373 K, 1 473 K and 1 573 K were investigated by means of back-scattered electron imaging, electron probe microanalysis and X-ray diffraction. The isothermal sections at 1 373 K, 1 473 K and 1 573 K consist of two three-phase regions and seven two-phase regions, without any ternary compounds. The compounds of NbSi{sub 2} and TaSi{sub 2}, αNb{sub 5}Si{sub 3} and αTa{sub 5}Si{sub 3} form continuous solid solutions, respectively. The solubilities of Nb in Ta{sub 3}Si and Ta{sub 2}Si phases are extremely large, whereas the solubility of Si in the β(Nb, Ta) phase is relatively small.

  20. Determination of uranium and polonium in Spa rus aura ta by alpha spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Luna P, M.; Renteria, M.; Montero C, M. E. [Centro de Investigacion en Materiales Avanzados, S. C., Miguel de Cervantes No. 120, Complejo Industrial Chihuahua, 31109 Chihuahua (Mexico); Manjon C, G.; Diaz, I., E-mail: elena.montero@cimav.edu.mx [Universidad de Sevilla, Escuela Tecnica Superior de Arquitectura, Departamento de Fisica Aplicada II, San Fernando No. 4, 41004 Sevilla (Spain)

    2012-06-15

    The aim of this study was optimizing conditions for the specific activities determination of some uranium-series radionuclides present in Spa rus aura ta by alpha spectrometry. Determinations of specific activities were conducted varying the type of digestion: acid attack on hot plate, controlled microwave digestion and acid attack after calcination of the sample. The latter procedure was applied only to the case of uranium isotopes determination. The variation in the isotope extraction method consisted of applying the techniques of liquid-liquid extracting using Tributyl phosphate or chromatographic UTEVA resin. Results depending on the type of treatment given to the samples were compared based on obtained chemical yields. The results reveal a higher bioaccumulation of polonium in the liver sample, with activities of 0.809, 2.495 and 2.439 Bq kg{sup -1} fresh wt compared with the fillet. The best chemical yields of polonium were close to 60% for samples that were digested by microwave. In the case of uranium the best chemical yields, close to 80% for fillet, were obtained with a previous calcination of the sample and using the UTEVA resin. (Author)

  1. Determination of uranium and polonium in Spa rus aura ta by alpha spectrometry

    International Nuclear Information System (INIS)

    Luna P, M.; Renteria, M.; Montero C, M. E.; Manjon C, G.; Diaz, I.

    2012-01-01

    The aim of this study was optimizing conditions for the specific activities determination of some uranium-series radionuclides present in Spa rus aura ta by alpha spectrometry. Determinations of specific activities were conducted varying the type of digestion: acid attack on hot plate, controlled microwave digestion and acid attack after calcination of the sample. The latter procedure was applied only to the case of uranium isotopes determination. The variation in the isotope extraction method consisted of applying the techniques of liquid-liquid extracting using Tributyl phosphate or chromatographic UTEVA resin. Results depending on the type of treatment given to the samples were compared based on obtained chemical yields. The results reveal a higher bioaccumulation of polonium in the liver sample, with activities of 0.809, 2.495 and 2.439 Bq kg -1 fresh wt compared with the fillet. The best chemical yields of polonium were close to 60% for samples that were digested by microwave. In the case of uranium the best chemical yields, close to 80% for fillet, were obtained with a previous calcination of the sample and using the UTEVA resin. (Author)

  2. Nb and Ta Co-Doped TiO2 Transparent Conductive Thin Films by Magnetron Sputtering: Fabrication, Structure, and Characteristics

    Science.gov (United States)

    Liu, Yang; Peng, Qian; Qiao, Yadong; Yang, Guang

    2018-06-01

    Nb and Ta co-doped anatase titanium dioxide (NTTO) nanocrystalline thin films were deposited on quartz and Si (100) substrates by RF magnetron sputtering. The influence of RF power on the growth, structure, morphology, and properties of the samples are discussed in detail. X-ray diffraction measurements show that the films are polycrystalline with anatase tetragonal structure, which is further confirmed by Raman spectroscopy analysis. Meanwhile, Raman spectroscopy results indicate that the peak width of E g(1) mode, which is directly correlated to the carrier density, changes obviously with RF power. It is found that the substitution of Nb5+ and Ta5+ at Ti site is significantly improved with the increase of RF power from 150 W to 210 W. For the sample deposited at 210 W, the optical transmittance is above 82% in the visible range and the electrical resistivity is as low as 1.3 × 10-3 Ω cm with carrier density of 1.1 × 1021 cm-3 and Hall mobility of 4.5 cm2 V-1 s-1. The optical and electrical properties of NTTO thin films can be compared to those of Nb or Ta doped anatase TiO2. However, co-doping with Nb and Ta gives a possible platform to complement the limitations of each individual dopant.

  3. Geology of the Western Part of Los Alamos National Laboratory (TA-3 to TA-16), Rio Grande Rift, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    C.J.Lewis; A.Lavine; S.L.Reneau; J.N.Gardner; R.Channell; C.W.Criswell

    2002-12-01

    We present data that elucidate the stratigraphy, geomorphology, and structure in the western part of Los Alamos National Laboratory between Technical Areas 3 and 16 (TA-3 and TA-16). Data include those gathered by geologic mapping of surficial, post-Bandelier Tuff strata, conventional and high-precision geologic mapping and geochemical analysis of cooling units within the Bandelier Tuff, logging of boreholes and a gas pipeline trench, and structural analysis using profiles, cross sections, structure contour maps, and stereographic projections. This work contributes to an improved understanding of the paleoseismic and geomorphic history of the area, which will aid in future seismic hazard evaluations and other investigations. The study area lies at the base of the main, 120-m (400-ft) high escarpment formed by the Pajarito fault, an active fault of the Rio Grande rift that bounds Los Alamos National Laboratory on the west. Subsidiary fracturing, faulting, and folding associated with the Pajarito fault zone extends at least 1,500 m (5,000 ft) to the east of the main Pajarito fault escarpment. Stratigraphic units in the study area include upper units of the Tshirege Member of the early Pleistocene Bandelier Tuff, early Pleistocene alluvial fan deposits that predate incision of canyons on this part of the Pajarito Plateau, and younger Pleistocene and Holocene alluvium and colluvium that postdate drainage incision. We discriminate four sets of structures in the area between TA-3 and TA-16: (a) north-striking faults and folds that mark the main zone of deformation, including a graben in the central part of the study area; (b) north-northwest-striking fractures and rare faults that bound the eastern side of the principal zone of deformation and may be the surface expression of deep-seated faulting; (c) rare northeast-striking structures near the northern limit of the area associated with the southern end of the Rendija Canyon fault; and (d) several small east

  4. Collective flows of protons and $\\pi^-$ mesons in $^{2}$H + C, Ta and He plus C, Ta collisions at 3.4 GeV/nucleon

    CERN Document Server

    Chkhaidze, L; Djobava, T; Kladnitskaya, E; Kharkhelauri, L; Uzhinsky, V

    2011-01-01

    Collective flows of protons and negative pions have been studied in (2)H + C, Ta and He + C, Ta collisions at an energy of 3.4 GeV/nucleon. The data have been obtained by the 2-m Propane Bubble Chamber (PBC-500) at JINR. It is found that the directed flow of protons and pi(-) mesons characterized by d /d(y) increases with increase of the mass numbers of colliding nucleus pairs; the elliptic proton flow points out of the reaction plane and also strengthens as the system mass increases; the negative pion directed flow is in the same reaction plane as the proton flow for the lighter (2H + C, He + C) systems and in the opposite direction for the heavier ((2)H + Ta, He + Ta) systems. In (2)H + C, He + C, C + C, C + Ne, (2)H + Ta, He + Ta, C + Cu, and C + Ta collisions, the linear dependence of directed and elliptic flow parameters from mass numbers of projectile and target nuclei, (A(P).A(T))(1/2), is similar for protons while for pi(-) mesons the dependence of directed flow parameters is stronger. The ultrarelati...

  5. Two transcription factors TaPpm1 and TaPpb1 co-regulate anthocyanin biosynthesis in purple pericarps of wheat

    Science.gov (United States)

    Jiang, Wenhui; Liu, Tianxiang; Nan, Wenzhi; Jeewani, Diddugodage Chamila; Niu, Yanlu; Li, Chunlian; Shi, Xue; Wang, Cong; Wang, Jiahuan; Li, Yang; Wang, Zhonghua

    2018-01-01

    Abstract Purple pericarps of bread wheat (Triticum aestivum L.) are a useful source of dietary anthocyanins. Previous mapping results indicated that the purple pericarp trait is controlled by two complementary genes located on chromosomes 7D and 2A. However, the identity of the genes and the mechanisms by which they regulate the trait are unknown. In this study, two transcription factors were characterised as anthocyanin activators in purple pericarps: TaPpm1 (purple pericarp-MYB 1) and TaPpb1 (purple pericarp-bHLH 1). Three non-functional variants were detected in the coding sequence of TaPpm1 from non-purple seed lines, in which the function of TaPpm1 was destroyed either by insertion-induced frame shifts or truncated peptides. There were six 261-bp tandem repeats in the promoter region of TaPpb1 in the purple-grained varieties, while there was only one repeat unit present in the non-purple varieties. Furthermore, using yeast two-hybrid, dual luciferase, yeast one-hybrid, and transient assays, we were able to demonstrate that the interaction of TaPpm1 and TaPpb1 co-regulates the synthesis of anthocyanin. Overall, our results provide a better understanding of the molecular basis of anthocyanin synthesis in the wheat pericarp and indicate the existence of an integrated regulatory mechanism that controls production. PMID:29562292

  6. Stormwater Pollution Prevention Plan - TA-60 Asphalt Batch Plant

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval, Leonard Frank [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2018-01-31

    This Storm Water Pollution Prevention Plan (SWPPP) was developed in accordance with the provisions of the Clean Water Act (33 U.S.C. §§1251 et seq., as amended), and the Multi-Sector General Permit for Storm Water Discharges Associated with Industrial Activity (U.S. EPA, June 2015) issued by the U.S. Environmental Protection Agency (EPA) for the National Pollutant Discharge Elimination System (NPDES) and using the industry specific permit requirements for Sector P-Land Transportation and Warehousing as a guide. This SWPPP applies to discharges of stormwater from the operational areas of the TA-60-01 Asphalt Batch Plant at Los Alamos National Laboratory. Los Alamos National Laboratory (also referred to as LANL or the “Laboratory”) is owned by the Department of Energy (DOE), and is operated by Los Alamos National Security, LLC (LANS). Throughout this document, the term “facility” refers to the TA-60 Asphalt Batch Plant and associated areas. The current permit expires at midnight on June 4, 2020.

  7. LAFD: TA-3 NISC & SCC Facility Familiarization Tour, OJT #53356

    Energy Technology Data Exchange (ETDEWEB)

    Rutherford, Victor Stephen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Norman, Rich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Montoya, Gene [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Blumberg, Paul A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); McCurdy, Patrick B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-10-24

    Los Alamos National Laboratory (LANL, the Laboratory, or the Lab) conducts familiarization tours for Los Alamos County Fire Department (LAFD) personnel at the Strategic Computing Complex (SCC), TA-03-2327, and the Nonproliferation & International Security Complex (NISC), TA-03-2322. These tours are official LANL business; their purpose is to orient the firefighters to the SCC and the NISC so that they can respond efficiently and quickly to a variety of emergency situations. The tour includes ingress and egress of the buildings, layout and organization of the buildings, evacuation procedures, and areas of concern to emergency responders within these buildings. LAFD firefighters have the training, skills, and abilities to perform these emergency responder tasks; other LANL personnel who have the required clearance level cannot perform these tasks. This handout provides details of the information, along with maps and diagrams, to be presented during the familiarization tours. The report will be distributed to the trainees at the time of the tour. A corresponding checklist will also be used as guidance during the familiarization tours to ensure that all required information is presented to the LAFD personnel.

  8. Stormwater Pollution Prevention Plan - TA-60 Material Recycling Facility

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval, Leonard Frank [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2018-01-31

    This Storm Water Pollution Prevention Plan (SWPPP) was developed in accordance with the provisions of the Clean Water Act (33 U.S.C. §§1251 et seq., as amended), and the Multi-Sector General Permit for Storm Water Discharges Associated with Industrial Activity (U.S. EPA, June 2015) issued by the U.S. Environmental Protection Agency (EPA) for the National Pollutant Discharge Elimination System (NPDES) and using the industry specific permit requirements for Sector P-Land Transportation and Warehousing as a guide. This SWPPP applies to discharges of stormwater from the operational areas of the TA- 60 Material Recycling Facility at Los Alamos National Laboratory. Los Alamos National Laboratory (also referred to as LANL or the “Laboratory”) is owned by the Department of Energy (DOE), and is operated by Los Alamos National Security, LLC (LANS). Throughout this document, the term “facility” refers to the TA-60 Material Recycling Facility. The current permit expires at midnight on June 4, 2020.

  9. Density Measurement of Liquid Ni-Ta Alloys by a Modified Sessile Drop Method

    Institute of Scientific and Technical Information of China (English)

    FANG Liang; XIAO Feng; TAO Zainan; Kusuhiro Mukai

    2005-01-01

    The density of liquid Ni-Ta alloys was measured by using a modified sessile drop method. It is found that the density of the liquid Ni-Ta alloys decreases with the increasing temperature, but increases with the increase of tantalum concentration in the alloys. The molar volume of liquid Ni-Ta binary alloys increases with the increase of temperature and tantalum concentration.

  10. TaS2 nanosheet-based room-temperature dosage meter for nitric oxide

    Directory of Open Access Journals (Sweden)

    Qiyuan He

    2014-09-01

    Full Text Available A miniature dosage meter for toxic gas is developed based on TaS2 nanosheets, which is capable of indicating the toxic dosage of trace level NO at room temperature. The TaS2 film-based chemiresistor shows an irreversible current response against the exposure of NO. The unique non-recovery characteristic makes the TaS2 film-based device an ideal indicator of total dosage of chronicle exposure.

  11. Characterisation of Ta-based barrier films on SiLK for Cu-metalisation

    NARCIS (Netherlands)

    van Nieuwkasteele-Bystrova, Svetlana Nikolajevna; Holleman, J.; Woerlee, P.H.; Wolters, Robertus A.M.

    2002-01-01

    Structures with Ta, TaxN1-x, Ta90C10, Ta95Si5 on SiLK were tested using in-situ 4- point probe resistance measurements during annealing up to 400oC. The change in normalized resistance by a factor of up to 2.58 was attributed to oxygen diffusion out of SiLK layer into the barriers. No direct

  12. Wheat TaSP gene improves salt tolerance in transgenic Arabidopsis thaliana.

    Science.gov (United States)

    Ma, Xiaoli; Cui, Weina; Liang, Wenji; Huang, Zhanjing

    2015-12-01

    A novel salt-induced gene with unknown functions was cloned through analysis of gene expression profile of a salt-tolerant wheat mutant RH8706-49 under salt stress. The gene was named Triticum aestivum salt-related protein (TaSP) and deposited in GenBank (Accession No. KF307326). Quantitative polymerase chain reaction (qPCR) results showed that TaSP expression was induced under salt, abscisic acid (ABA), and polyethylene glycol (PEG) stresses. Subcellular localization revealed that TaSP was mainly localized in cell membrane. Overexpression of TaSP in Arabidopsis could improve salt tolerance of 35S::TaSP transgenic Arabidopsis. 35S::TaSP transgenic Arabidopsis lines after salt stress presented better physiological indexes than the control group. In the non-invasive micro-test (NMT), an evident Na(+) excretion was observed at the root tip of salt-stressed 35S::TaSP transgenic Arabidopsis. TaSP promoter was cloned, and its beta-glucuronidase (GUS) activities before and after ABA, salt, cold, heat, and salicylic acid (SA) stresses were determined. Full-length TaSP promoter contained ABA and salt response elements. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  13. Morphological instability of Ag films caused by phase transition in the underlying Ta barrier layer

    Energy Technology Data Exchange (ETDEWEB)

    Mardani, Shabnam, E-mail: shabnam.mardani@angstrom.uu.se; Vallin, Örjan; Wätjen, Jörn Timo; Norström, Hans; Olsson, Jörgen; Zhang, Shi-Li, E-mail: shili.zhang@angstrom.uu.se [Solid State Electronics, The Ångström Laboratory, Uppsala University, P.O. Box 534, SE-75121 (Sweden)

    2014-08-18

    Wide-bandgap (WBG) semiconductor technologies are maturing and may provide increased device performance in many fields of applications, such as high-temperature electronics. However, there are still issues regarding the stability and reliability of WBG devices. Of particular importance is the high-temperature stability of interconnects for electronic systems based on WBG-semiconductors. For metallization without proper encapsulation, morphological degradation can occur at elevated temperatures. Sandwiching Ag films between Ta and/or TaN layers in this study is found to be electrically and morphologically stabilize the Ag metallization up to 800 °C, compared to 600 °C for uncapped films. However, the barrier layer plays a key role and TaN is found to be superior to Ta, resulting in the best achieved stability, whereas the difference between Ta and TaN caps is negligible. The β-to-α phase transition in the underlying Ta barrier layer is identified as the major cause responsible for the morphological instability observed above 600 °C. It is shown that this phase transition can be avoided using a stacked Ta/TaN barrier.

  14. Overexpression of a Triticum aestivum Calreticulin gene (TaCRT1 Improves Salinity Tolerance in Tobacco.

    Directory of Open Access Journals (Sweden)

    Yang Xiang

    Full Text Available Calreticulin (CRT is a highly conserved and abundant multifunctional protein that is encoded by a small gene family and is often associated with abiotic/biotic stress responses in plants. However, the roles played by this protein in salt stress responses in wheat (Triticum aestivum remain obscure. In this study, three TaCRT genes were identified in wheat and named TaCRT1, TaCRT2 and TaCRT3-1 based on their sequence characteristics and their high homology to other known CRT genes. Quantitative real-time PCR expression data revealed that these three genes exhibit different expression patterns in different tissues and are strongly induced under salt stress in wheat. The calcium-binding properties of the purified recombinant TaCRT1 protein were determined using a PIPES/Arsenazo III analysis. TaCRT1 gene overexpression in Nicotiana tabacum decreased salt stress damage in transgenic tobacco plants. Physiological measurements indicated that transgenic tobacco plants showed higher activities of superoxide dismutase (SOD, peroxidase (POD and catalase (CAT than non-transgenic tobacco under normal growth conditions. Interestingly, overexpression of the entire TaCRT1 gene or of partial TaCRT1 segments resulted in significantly higher tolerance to salt stress in transgenic plants compared with their WT counterparts, thus revealing the essential role of the C-domain of TaCRT1 in countering salt stress in plants.

  15. Civil society engagement in multi-stakeholder dialogue: a qualitative study exploring the opinions and perceptions of MeTA members.

    Science.gov (United States)

    Buckland-Merrett, Gemma L; Kilkenny, Catherine; Reed, Tim

    2017-01-01

    The Medicines Transparency Alliance (MeTA) is an initiative that brings together all stakeholders in the medicines market to create a multi-stakeholder dialogue and improve access, availability and affordability of medicines. Key to this multi-stakeholder dialogue is the participation of Civil Society Organisations. A recent MeTA annual review, identified uneven engagement of civil society organisations in the multi-stakeholder process. This study was designed to explore the engagement of Civil Society Organisations in the MeTA multi-stakeholder process and the factors influencing their participation. Participants were drawn from a convenience sample of key MeTA informants attending a MeTA global meeting in Geneva in 2014. Study participants consisted of members of MeTA, which included representatives from government, the private sector and civil society. In-depth semi-structured face-to-face interviews were conducted to identify perceptions around the barriers to civil society engagement in the multi-stakeholder process. Interviews were guided by a conceptual framework exploring the three main themes of the political environment, relative stakeholder strength and agenda setting/gatekeepers. Interviews were structured to enable additional themes to emerge and be explored. Fifteen interviews were conducted. The interviews were audio recorded, transcribed verbatim and analysed using a general inductive approach. All interviewees provided written informed consent. Findings were captured within three main overarching themes: the political environment, relative stakeholder strength and agenda setting/gatekeepers, with the opportunity for additional themes to emerge in the interviewing process. The study conformed these three themes were important in the engagement process. Participants reported that civil society engagement is particularly limited by those who set the agenda. It was largely seen that the political environment was the significant factor that enabled or

  16. Relationship between interlayer hydration and photocatalytic water splitting of A'1-xNaxCa2Ta3O10.nH2O (A'=K and Li)

    International Nuclear Information System (INIS)

    Mitsuyama, Tomohiro; Tsutsumi, Akiko; Sato, Sakiko; Ikeue, Keita; Machida, Masato

    2008-01-01

    Partial replacement of alkaline metals in anhydrous KCa 2 Ta 3 O 10 and LiCa 2 Ta 3 O 10 was studied to control interlayer hydration and photocatalytic activity for water splitting under UV irradiation. A' 1-x Na x Ca 2 Ta 3 O 10 .nH 2 O (A'=K and Li) samples were synthesized by ion exchange of CsCa 2 Ta 3 O 10 in mixed molten nitrates at 400 deg. C. In K 1-x Na x Ca 2 Ta 3 O 10 .nH 2 O, two phases with the orthorhombic (C222) and tetragonal (I4/mmm) structures were formed at x≤0.7 and x≥0.5, respectively. Upon replacement by Na + having a larger enthalpy of hydration (ΔH h 0 ), the interlayer hydration occurred at x≥0.3 and the hydration number (n) was increased monotonically with an increase of x. Li 1-x Na x Ca 2 Ta 3 O 10 .nH 2 O showed a similar hydration behavior, but the phase was changed from I4/mmm (x 1-x Na x Ca 2 Ta 3 O 10 .nH 2 O exhibited the activity increasing in consistent with n, whereas Li 1-x Na x Ca 2 Ta 3 O 10 .nH 2 O exhibited the activity maximum at x=0.77, where the rates of H 2 /O 2 evolution were nearly doubled compared with those for end-member compositions (x=0 and 1). - Graphical abstract: The partial substitution of Na in the interlayer of anhydrous-layered perovskite has been found as useful structural modification toward highly active hydrated photocatalysts

  17. Effect of Ta substitution method on the mechanical properties of Ni3(Si,Ti) intermetallic alloy

    International Nuclear Information System (INIS)

    Imajo, Daiki; Kaneno, Yasuyuki; Takasugi, Takayuki

    2013-01-01

    In this study, Ta was added to an L1 2 -type Ni 3 (Si,Ti) alloy at different levels and into different substitution sites, substituting for either Ni, Ti or Si. The solubility limits of Ta in the L1 2 phase were 1.9 at%, 5.7 at% and 1.0 at% when Ta substituted for Ni, Ti and Si, respectively. The lattice parameters in the L1 2 phase region increased in the order of the Ta(Ni)>Ta(Si)>Ta(Ti) quaternary alloys, in which Ta substituted for Ni, Si and Ti, respectively. The room-temperature hardness in the L1 2 phase region increased linearly with increasing Ta content, and the increment rate increased in the order of the Ta(Ni)>Ta(Si)>Ta(Ti) quaternary alloys. Similarly, the room-temperature 0.2% proof stress as well as the tensile strength in the L1 2 phase region increased linearly with increasing Ta content, and the increment rate increased in the order of the Ta(Ni)>Ta(Si)>Ta(Ti) quaternary alloys. High tensile elongation was observed at room temperature when the microstructures remain in the L1 2 single phase. At high temperatures, a positive temperature dependence of the hardness as well as the flow strength was observed in the quaternary alloys. It was also shown that the wear resistance of the quaternary Ta(Ti) alloys was improved and attributed to plastically induced hardening of the worn surfaces combined with the positive temperature dependence of the flow strength. The strengthening and hardening resulting from Ta addition was suggested to be due to the hardening of the solid solution arising from the misfits in the atomic radius between Ta and the constituent atoms Ni, Ti or Si

  18. Effect of Ta substitution method on the mechanical properties of Ni{sub 3}(Si,Ti) intermetallic alloy

    Energy Technology Data Exchange (ETDEWEB)

    Imajo, Daiki; Kaneno, Yasuyuki; Takasugi, Takayuki, E-mail: takasugi@mtr.osakafu-u.ac.jp

    2013-12-20

    In this study, Ta was added to an L1{sub 2}-type Ni{sub 3}(Si,Ti) alloy at different levels and into different substitution sites, substituting for either Ni, Ti or Si. The solubility limits of Ta in the L1{sub 2} phase were 1.9 at%, 5.7 at% and 1.0 at% when Ta substituted for Ni, Ti and Si, respectively. The lattice parameters in the L1{sub 2} phase region increased in the order of the Ta(Ni)>Ta(Si)>Ta(Ti) quaternary alloys, in which Ta substituted for Ni, Si and Ti, respectively. The room-temperature hardness in the L1{sub 2} phase region increased linearly with increasing Ta content, and the increment rate increased in the order of the Ta(Ni)>Ta(Si)>Ta(Ti) quaternary alloys. Similarly, the room-temperature 0.2% proof stress as well as the tensile strength in the L1{sub 2} phase region increased linearly with increasing Ta content, and the increment rate increased in the order of the Ta(Ni)>Ta(Si)>Ta(Ti) quaternary alloys. High tensile elongation was observed at room temperature when the microstructures remain in the L1{sub 2} single phase. At high temperatures, a positive temperature dependence of the hardness as well as the flow strength was observed in the quaternary alloys. It was also shown that the wear resistance of the quaternary Ta(Ti) alloys was improved and attributed to plastically induced hardening of the worn surfaces combined with the positive temperature dependence of the flow strength. The strengthening and hardening resulting from Ta addition was suggested to be due to the hardening of the solid solution arising from the misfits in the atomic radius between Ta and the constituent atoms Ni, Ti or Si.

  19. Corrosion resistance after mechanical deformation of the Ti30Ta experimental alloy for using in biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Kerolene Barboza da; Konatu, Reginaldo Toshihiro; Oliveira, Liliane Lelis de; Nakazato, Roberto Zenhei; Claro, Ana Paula Rosifini Alves, E-mail: rosifini@feg.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Guaratinguetá, SP (Brazil). Departamento de Engenharia de Materiais

    2017-10-15

    In this study the corrosion resistance of Ti30Ta experimental alloy was evaluated when submitted to different deformation rates. Alloys were processed in arc melting, furnace, forged and treated. The samples were machined in accordance with ASTME9-09 standard to carry out compression tests. The influence of deformation was evaluated by optical microscopy and XRD, and Electrochemical parameters were analyzed in the most severe condition of deformation (22%). Corrosion resistance exhibited the same behavior for two conditions, 22% and without deformation. (author)

  20. Mutagenic and antimutagenic activities of Artemisia absinthium volatile oil by the bacterial reverse mutation assay in Salmonella typhimurium strains TA98 and TA100

    Directory of Open Access Journals (Sweden)

    Mahboubeh Taherkhani

    2014-09-01

    Full Text Available Objective: To investigate the mutagenic and antimutagenic activities of Artemisia absinthium L. (A. absinthium essential oil by the bacterial reverse mutation assay in Salmonella typhimurium (S. typhimurium strains. Methods: Water-distilled essential oil of A. absinthium collected from Ardabil, NorthWestern Iran, was investigated for mutagenic and antimutagenic activities. In present study, the mutagenic and antimutagenic activities of A. absinthium oil were investigated by the bacterial revere mutation assay in S. typhimurium TA98 and TA100 strains with and without S9 (microsomal mutagenesis assay. Results: The comparative mutagenicity effect was seen in 1.5 mg/plate by the bacterial reverse mutation assay in S. typhimurium TA98 strains, without S9 and the excellent antimutagenicity effect was seen in 1.5 mg/plate against S. typhimurium TA100, without S9. Conclusions: The mutagenicity and antimutagenicity effects of the volatile oil of A. absinthium were seen without the presence of metabolic activation.

  1. Synthesis, crystal structure and properties of K2Ta2S10: A novel ternary tantalum polysulfide with TaS8 polyhedra forming infinite anionic chains

    International Nuclear Information System (INIS)

    Wu Yuandong; Naether, Christian; Bensch, Wolfgang

    2005-01-01

    The new ternary alkali tantalum polysulfide K 2 Ta 2 S 10 has been synthesized by reacting TaS 2 with an in situ formed melt of K 2 S 3 and S at 773K. The compound crystallizes with four formula units in the monoclinic space group P2 1 /n (No. 14) with lattice parameters of a=14.9989(13)A,b=6.4183(4)A,c=15.1365(13)A,β=117.629(9) o . The structure contains two different zigzag chain anions [TaS 5 ] - , running parallel to the crystallographic b-axis separated by potassium cations. The two crystallographically independent tantalum atoms are in a distorted bi-capped trigonal prismatic environment of eight sulfur atoms which was never observed before. The TaS 8 polyhedra share three S atoms on each side to form the anionic chains. The compound was characterized with FIR and Raman spectroscopy

  2. Low-Level, Measured Response of Los Alamos National Laboratories TA 16 - Building 411 and TA 8 - Building 23 to Direct Flash Attachment of Lightning

    International Nuclear Information System (INIS)

    Dinallo, Michael A.; Holmes, Parris; Merewether, Kimball O.; Morris, Marvin E.

    1999-01-01

    On September 24, 25, 28, and 29, 1998 and on October 19 and 23, 1998, transfer impedance measurements were made on Los Alamos National Laboratories TA 16 - Building 411 and TA 8-- Building 23 to characterize their interior open-circuit voltage response to a direct lightning flash attachment to the structures. The theory, history, measurement methods and equipment, and specific measured results are detailed. The measured results demonstrate that if the remaining metallic penetrations are bonded, then the rebar of the two structures is sufficiently well connected to form a Faraday cage that reduces the maximum open-circuit voltage inside the structure to a sufficiently low level that the required standoff distance to prevent arcing to explosive assemblies is 6.8 inches for TA 16 - Building 411 and is 11.5 inches for TA 8 - Building 23

  3. Professor Ta-You Wu and his ideas of science

    International Nuclear Information System (INIS)

    Ye Minghan; Dai Nianzu

    2005-01-01

    The career of Professor Ta-You Wu and his contributions in the latter half of his life in Taiwan, China are briefly reviewed. The authors focus our discussion on some of his ideas in pushing forward the advancement of science and technology in Taiwan and in promoting scientific standards. These ideas include: emphasis on the importance of basic science and qualified personnel as the foundation for the development of science and technology, and while advocating applied science he pointed out that 'future profits depend on high technology'. Thus, he contributed greatly to the rise of the economy in Taiwan. His view of the dispute between Bohr and Einstein is also briefly reviewed, as well as his principles of leadership as the president of Academia Sinica, Taiwan. (author)

  4. MoNbTaV Medium-Entropy Alloy

    Directory of Open Access Journals (Sweden)

    Hongwei Yao

    2016-05-01

    Full Text Available Guided by CALPHAD (Calculation of Phase Diagrams modeling, the refractory medium-entropy alloy MoNbTaV was synthesized by vacuum arc melting under a high-purity argon atmosphere. A body-centered cubic solid solution phase was experimentally confirmed in the as-cast ingot using X-ray diffraction and scanning electron microscopy. The measured lattice parameter of the alloy (3.208 Å obeys the rule of mixtures (ROM, but the Vickers microhardness (4.95 GPa and the yield strength (1.5 GPa are about 4.5 and 4.6 times those estimated from the ROM, respectively. Using a simple model on solid solution strengthening predicts a yield strength of approximately 1.5 GPa. Thermodynamic analysis shows that the total entropy of the alloy is more than three times the configurational entropy at room temperature, and the entropy of mixing exhibits a small negative departure from ideal mixing.

  5. Ti-25Ta-Zr alloys for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Kuroda, Pedro Akira Bazaglia; Quadros, Fernanda Freitas; Grandini, Carlos Roberto, E-mail: pedro@fc.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Bauru, SP (Brazil). Faculdade de Ciencias

    2016-07-01

    Full text: The most widely used titanium alloy for biomedical applications is Ti-6Al-4V, however, previous studies showed that vanadium cause allergic reactions in human tissue and aluminum has been associated with neurological disorders. Then, to solve this problem, new titanium alloys without the presence of these elements are being developed, with the addition of different elements, usually the β-stabilizers, which can change its microstructure and mechanical properties, and may make the titanium and its alloys, most promising for use as biomaterial. In this paper the development and characterization of Ti-25Ta-(10-40)Zr alloys, for biomedical applications are discussed. X-ray diffraction results show the coexistence of α', α” and β phases, which are corroborated by SEM results. The results of microhardness and elastic modulus present an anomaly for the alloy with 10 wt% Zr, due, probably the presence of ω phase. (author)

  6. TA-03-0035 Press Building – D&D

    Energy Technology Data Exchange (ETDEWEB)

    Hasenack, Marvin Leroy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-11-02

    The Press Building was constructed in 1954 with 15,073 ft2 of floor space. It was built to house a 5000 ton double action Lake Erie hydraulic press and a uranium casting area. Missions included uranium activities associated with the Nuclear Weapons and Rover Rocket programs. At the end of the Rover program, the building continued to support various uranium materials science projects until the building was placed into a cold and dark status in 2013 and then was demolished in 2017. The building interior, the press, and associated systems were radiological contaminated and disposed of as low level waste. The demolition of this building opened up valuable real estate in the TA-3 area for the future construction of an ~11,000 Sq. Ft. Biosafety Level 2 laboratory and office building. This building will support the ongoing Bioscience Division mission at the laboratory.

  7. Switching dynamics of TaOx-based threshold switching devices

    Science.gov (United States)

    Goodwill, Jonathan M.; Gala, Darshil K.; Bain, James A.; Skowronski, Marek

    2018-03-01

    Bi-stable volatile switching devices are being used as access devices in solid-state memory arrays and as the active part of compact oscillators. Such structures exhibit two stable states of resistance and switch between them at a critical value of voltage or current. A typical resistance transient under a constant amplitude voltage pulse starts with a slow decrease followed by a rapid drop and leveling off at a low steady state value. This behavior prompted the interpretation of initial delay and fast transition as due to two different processes. Here, we show that the entire transient including incubation time, transition time, and the final resistance values in TaOx-based switching can be explained by one process, namely, Joule heating with the rapid transition due to the thermal runaway. The time, which is required for the device in the conducting state to relax back to the stable high resistance one, is also consistent with the proposed mechanism.

  8. Electron Cloud at Low Emittance in CesrTA

    CERN Document Server

    Palmer, Mark; Billing, Michael; Calvey, Joseph; Conolly, Christopher; Crittenden, James; Dobbins, John; Dugan, Gerald; Eggert, Nicholas; Fontes, Ernest; Forster, Michael; Gallagher, Richard; Gray, Steven; Greenwald, Shlomo; Hartill, Donald; Hopkins, Walter; Kreinick, David; Kreis, Benjamin; Leong, Zhidong; Li, Yulin; Liu, Xianghong; Livezey, Jesse; Lyndaker, Aaron; Makita, Junki; McDonald, Michael; Medjidzade, Valeri; Meller, Robert; O'Connell, Tim; Peck, Stuart; Peterson, Daniel; Ramirez, Gabriel; Rendina, Matthew; Revesz, Peter; Rider, Nate; Rice, David; Rubin, David; Sagan, David; Savino, James; Schwartz, Robert; Seeley, Robert; Sexton, James; Shanks, James; Sikora, John; Smith, Eric; Strohman, Charles; Williams, Heather; Antoniou, Fanouria; Calatroni, Sergio; Gasior, Marek; Jones, Owain Rhodri; Papaphilippou, Yannis; Pfingstner, Juergen; Rumolo, Giovanni; Schmickler, Hermann; Taborelli, Mauro; Asner, David; Boon, Laura; Garfinkel, Arthur; Byrd, John; Celata, Christine; Corlett, John; De Santis, Stefano; Furman, Miguel; Jackson, Alan; Kraft, Rick; Munson, Dawn; Penn, Gregory; Plate, David; Venturini, Marco; Carlson, Benjamin; Demma, Theo; Dowd, Rohan; Flanagan, John; Jain, Puneet; Kanazawa, Ken-ichi; Kubo, Kiyoshi; Ohmi, Kazuhito; Sakai, Hiroshi; Shibata, Kyo; Suetsugu, Yusuke; Tobiyama, Makoto; Gonnella, Daniel; Guo, Weiming; Harkay, Katherine; Holtzapple, Robert; Jones, James; Wolski, Andrzej; Kharakh, David; Ng, Johnny; Pivi, Mauro; Wang, Lanfa; Ross, Marc; Tan, Cheng-Yang; Zwaska, Robert; Schachter, Levi; Wilkinson, Eric

    2010-01-01

    The Cornell Electron Storage Ring (CESR) has been reconfigured as a test accelerator (CesrTA) for a program of electron cloud (EC) research at ultra low emittance. The instrumentation in the ring has been upgraded with local diagnostics for measurement of cloud density and with improved beam diagnostics for the characterization of both the low emittance performance and the beam dynamics of high intensity bunch trains interacting with the cloud. A range of EC mitigation methods have been deployed and tested and their effectiveness is discussed. Measurements of the electron cloud’s effect on the beam under a range of conditions are discussed along with the simulations being used to quantitatively understand these results

  9. TaC Studios New Construction Test House

    Energy Technology Data Exchange (ETDEWEB)

    Butler, T.; Curtis, O.; Kim, E.; Roberts, S.; Stephenson, R.

    2013-03-01

    As part of the NAHB Research Center Industry Partnership, Southface partnered with TaC Studios, an Atlanta based architecture firm specializing in residential and light commercial design, on the construction of a new test home in Atlanta, GA in the mixed humid climate zone. This home will serve as a model home for the builder partner and addresses Building America energy savings targets through the planning and implementation of a design package will serve as a basis of design for the builder partner's future homes. As a BA test house, this home will be evaluated to detail whole house energy use, end use loads, and HVAC and hot water efficiency.

  10. ISTS of Fe adatoms in contact to superconducting Ta

    Energy Technology Data Exchange (ETDEWEB)

    Kamlapure, Anand; Cornils, Lasse; Wiebe, Jens; Wiesendanger, Roland [Department of Physics, Hamburg University, Hamburg (Germany); Zhou, Lihui [Department of Physics, Hamburg University, Hamburg (Germany); Max-Planck Institute for Solid State-Research, Stuttgart (Germany); Khajetoorians, Alexander A. [Department of Physics, Hamburg University, Hamburg (Germany); Institute for Molecules and Materials, Radboud University, Nijmegen (Netherlands)

    2015-07-01

    Recent local scale investigations of the competition of superconductivity and magnetism in molecular systems revealed rich physics associated with a quantum phase transition. Here, we experimentally study individual Fe atoms adsorbed on a reconstructed surface of superconducting Ta by inelastic scanning tunneling spectroscopy (ISTS) at a temperature of 1 K and as a function of magnetic field of strength up to 3 T perpendicular to the surface. We observe strong inelastic excitations at three different adsorption sites of the Fe adatoms. The majority site shows a sharp step around 2 meV which is almost independent of the magnetic field. The other two sites exhibit excitations around 1 meV and 4 meV which have a weak magnetic field dependence indicating the magnetic origin of this excitation. In all three cases the superconducting energy gap and coherence peaks are preserved at zero magnetic field indicating very weak coupling between the magnetic moment and the cooper pairs.

  11. Effects of thickness and annealing condition on magnetic properties and thermal stabilities of Ta/Nd/NdFeB/Nd/Ta sandwiched films

    Science.gov (United States)

    Liu, Wen-Feng; Zhang, Min-Gang; Zhang, Ke-Wei; Zhang, Hai-Jie; Xu, Xiao-Hong; Chai, Yue-Sheng

    2016-11-01

    Ta/Nd/NdFeB/Nd/Ta sandwiched films are deposited by magnetron sputtering on Si (100) substrates, and subsequently annealed in vacuum at different temperatures for different time. It is found that both the thickness of NdFeB and Nd layer and the annealing condition can affect the magnetic properties of Ta/Nd/NdFeB/Nd/Ta films. Interestingly, the thickness and annealing temperature show the relevant behaviors that can affect the magnetic properties of the film. The high coercivity of 24.1 kOe (1 Oe = 79.5775 A/m) and remanence ratio (remanent magnetization/saturation magnetization) of 0.94 can be obtained in a Ta/Nd(250 nm)/NdFeB(600 nm)/Nd(250 nm)/Ta film annealed for 3 min at 1023 K. In addition, the thermal stability of the film is also linked to the thickness of NdFeB and Nd layer and the annealing temperature as well. The excellent thermal stability can be achieved in a Ta/Nd(250 nm)/NdFeB(600 nm)/Nd(250 nm)/Ta film annealed at 1023 K. Program supported by the National Natural Science Foundation of China (Grant No. 51305290), the Higher Education Technical Innovation Project of Shanxi Province, China (Grant No. 2013133), the Fund Program for the Scientific Activities of Selected Returned Overseas Professionals of Shanxi Province, China (Grant No. 2015003), and the Program for the Key Team of Scientific and Technological Innovation of Shanxi Province, China (Grant No. 2013131009).

  12. Genome-Wide Identification of Cyclic Nucleotide-Gated Ion Channel Gene Family in Wheat and Functional Analyses of TaCNGC14 and TaCNGC16

    Directory of Open Access Journals (Sweden)

    Jia Guo

    2018-01-01

    Full Text Available Cyclic nucleotide gated channels (CNGCs play multifaceted roles in plants, particularly with respect to signaling processes associated with abiotic stress signaling and during host-pathogen interactions. Despite key roles during plant survival and response to environment, little is known about the activity and function of CNGC family in common wheat (Triticum aestivum L., a key stable food around the globe. In this study, we performed a genome-wide identification of CNGC family in wheat and identified a total 47 TaCNGCs in wheat, classifying these genes into four major groups (I–IV with two sub-groups (IVa and IVb. Sequence analysis revealed the presence of several conserved motifs, including a phosphate binding cassette (PBC and a “hinge” region, both of which have been hypothesized to be critical for the function of wheat CNGCs. During wheat infection with Pst, the transcript levels of TaCNGC14 and TaCNGC16, both members of group IVb, showed significant induction during a compatible interaction, while a reduction in gene expression was observed in incompatible interactions. In addition, TaCNGC14 and TaCNGC16 mRNA accumulation was significantly influenced by exogenously applied hormones, including abscisic acid (ABA, methyl jasmonate (MeJA, and salicylic acid (SA, suggesting a role in hormone signaling and/or perception. Silencing of TaCNGC14 and TaCNGC16 limited Pst growth and increased wheat resistance against Pst. The results presented herein contribute to our understanding of the wheat CNGC gene family and the mechanism of TaCNGCs signaling during wheat-Pst interaction.

  13. Structural evolution of a Ta-filament during hot-wire chemical vapour deposition of Silicon investigated by electron backscatter diffraction

    CSIR Research Space (South Africa)

    Oliphant, CJ

    2012-03-01

    Full Text Available , encapsulating a Ta inner core. The tantalum rich Ta5Si3, Si3Ta5 and Ta2Si phases however formed in addition to TaSi2 at the centre regions. Cracks and porosity were found throughout the length of the filament. The microstructure evolution of the aged tantalum...

  14. Synthesis, crystal structure, and magnetic properties of pyrochlore-type Eu{sub 2}Ta{sub 2}(O,N){sub 7+δ}

    Energy Technology Data Exchange (ETDEWEB)

    Anke, Bjoern; Hund, Sophie; Lorent, Christian; Lerch, Martin [Institut fuer Chemie, Technische Universitaet Berlin (Germany); Janka, Oliver; Block, Theresa; Poettgen, Rainer [Institut fuer Anorganische und Analytische Chemie, Universitaet Muenster (Germany)

    2017-12-13

    Pyrochlore-type Eu{sub 2}Ta{sub 2}(O,N){sub 7+δ} phases were prepared by reaction of ammonia with an amorphous europium tantalum oxide precursor. {sup 151}Eu Moessbauer and EPR spectroscopy as well as magnetic susceptibility measurements point to the presence of exclusively Eu{sup 3+}. For phase-pure samples (X-ray powder diffraction), the nitrogen content varies between 1.0 and 1.8 wt %, leading to compositions in the range Eu{sub 2}Ta{sub 2}O{sub 7.1}N{sub 0.6} - Eu{sub 2}Ta{sub 2}O{sub 6.5}N{sub 1.0}. Pyrochlore-type phases are structurally derived from the fluorite type with 1/8 of the anions missing, resulting in an ideal composition A{sub 2}B{sub 2}X{sub 7}. In Eu{sub 2}Ta{sub 2}(O,N){sub 7+δ} the excess anions partly occupy these vacancies. The prepared phases are colorless with a direct optical bandgap of 4.3 eV and they show the typical Van Vleck paramagnetic behavior known for trivalent Eu atoms. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Fabrication of NdFeB microstructures using a silicon molding technique for NdFeB/Ta multilayered films and NdFeB magnetic powder

    International Nuclear Information System (INIS)

    Jiang Yonggang; Fujita, Takayuki; Uehara, Minoru; Iga, Yuki; Hashimoto, Taichi; Hao, Xiuchun; Higuchi, Kohei; Maenaka, Kazusuke

    2011-01-01

    The silicon molding technique is described for patterning of NdFeB/Ta multilayered magnetic films and NdFeB magnetic powder at the micron scale. Silicon trenches are seamlessly filled by 12-μm-thick NdFeB/Ta multilayered magnetic films with a magnetic retentivity of 1.3 T. The topography image and magnetic field distribution image are measured using an atomic force microscope and a magnetic force microscope, respectively. Using a silicon molding technique complemented by a lift-off process, NdFeB magnetic powder is utilized to fabricate magnetic microstructures. Silicon trenches as narrow as 20 μm are filled by a mixture of magnetic powder and wax powder. The B-H hysteresis loop of the patterned magnetic powder is characterized using a vibrating sample magnetometer, which shows a magnetic retentivity of approximately 0.37 T. - Highlights: → We demonstrate the fabrication of micro-magnets using silicon molding processes. → NdFeB/Ta films are well filled in silicon trenches with a thickness of 12 μm. → The 12-μm-thick NdFeB/Ta magnetic film shows a retentivity of 1.3 T. → Magnetic structures as narrow as 20 μm are fabricated using NdFeB magnetic powder. → VSM measurement shows a retentivity of 0.37 T for patterned NdFeB magnetic powder.

  16. Fabrication of NdFeB microstructures using a silicon molding technique for NdFeB/Ta multilayered films and NdFeB magnetic powder

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Yonggang, E-mail: yonggangj@gmail.com [School of Mechanical Engineering and Automation, Beihang University, Xueyuan Road No. 37, Haidian District, Beijing 100191 (China); Maenaka Human-Sensing Fusion project, Japan Science and Technology Agency, 2167 Shosha, Himeji, Hyogo 671-2280 (Japan); Fujita, Takayuki [Maenaka Human-Sensing Fusion project, Japan Science and Technology Agency, 2167 Shosha, Himeji, Hyogo 671-2280 (Japan); Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280 (Japan); Uehara, Minoru [NEOMAX Co. Ltd., 2-15-17, Egawa, Shimamoto-Cho, Mishima-gun, Osaka 618-0013 (Japan); Iga, Yuki [Maenaka Human-Sensing Fusion project, Japan Science and Technology Agency, 2167 Shosha, Himeji, Hyogo 671-2280 (Japan); Hashimoto, Taichi [Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280 (Japan); Hao, Xiuchun; Higuchi, Kohei [Maenaka Human-Sensing Fusion project, Japan Science and Technology Agency, 2167 Shosha, Himeji, Hyogo 671-2280 (Japan); Maenaka, Kazusuke [Maenaka Human-Sensing Fusion project, Japan Science and Technology Agency, 2167 Shosha, Himeji, Hyogo 671-2280 (Japan); Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280 (Japan)

    2011-11-15

    The silicon molding technique is described for patterning of NdFeB/Ta multilayered magnetic films and NdFeB magnetic powder at the micron scale. Silicon trenches are seamlessly filled by 12-{mu}m-thick NdFeB/Ta multilayered magnetic films with a magnetic retentivity of 1.3 T. The topography image and magnetic field distribution image are measured using an atomic force microscope and a magnetic force microscope, respectively. Using a silicon molding technique complemented by a lift-off process, NdFeB magnetic powder is utilized to fabricate magnetic microstructures. Silicon trenches as narrow as 20 {mu}m are filled by a mixture of magnetic powder and wax powder. The B-H hysteresis loop of the patterned magnetic powder is characterized using a vibrating sample magnetometer, which shows a magnetic retentivity of approximately 0.37 T. - Highlights: > We demonstrate the fabrication of micro-magnets using silicon molding processes. > NdFeB/Ta films are well filled in silicon trenches with a thickness of 12 {mu}m. > The 12-{mu}m-thick NdFeB/Ta magnetic film shows a retentivity of 1.3 T. > Magnetic structures as narrow as 20 {mu}m are fabricated using NdFeB magnetic powder. > VSM measurement shows a retentivity of 0.37 T for patterned NdFeB magnetic powder.

  17. The magnetic hyperfine field in the 181Ta site in the Co2HfAl and Co2HfGa Heusler alloys

    International Nuclear Information System (INIS)

    Silva, R. da.

    1979-01-01

    The hyperfine magnetic fields at 181 Ta nuclei in Heusler alloys Co 2 HfZ (Z=Al, Ga) have been measured using the time differential perturbed gamma-gamma angular correlation (TDPAC) method. The hyperfine fields obtained from these measurements at the liquid nitrogen temperature are -189 and +- 150 kOersted for Co 2 HfAl and Co 2 HfGa, respectively. The concept that the hyperfine field at the Y site is similar to the solute fields in Fe, Co, Ni and Gd matrices is corroborated. We have verified that ratios H sub(hf) sub(Ta)/T sub(c) and H sub(hf) sub(Ta)μ sub(Co) in Co 2 HfZ compounds (Z=Al, Ga, Sn) do not depend on the nature of Z element. However a dependence in the value of observed field with the s-p element in Z site was noticed. We feel that the samples are not completely ordered cubic as observed by the quadrupole interaction measurements. The results are interpreted in terms of the Campbell-Blandin formalism, and it is shown that the spin polarization of conduction electrons at Hf and Ta have opposite signs. (Author) [pt

  18. Physicochemical Screening and Shelf Life Evaluation of Kuṅkumādi Ghṛta Prepared using Kesara and Nāgakesara.

    Science.gov (United States)

    Prajapati, Pradeep Kumar; Sharma, Rohit; Amrutia, Amee; Patgiri, B J

    2017-01-01

    Kuṅkumādi Ghṛta (KG) is an Ayurvedic formulation commonly recommended in skin disorders, especially Mukhadūṣikā (Acne vulgaris). Kesara (stigma of Crocus sativus Linn.) is a prime ingredient in the formulation. However, due to high cost and increased adulteration in Kesara, ' Nāgakesara ' ( Mesua ferrea Linn.) is suggested by Ayurvedic experts as a substitute. Nāgakesara is relatively lower in cost and possesses similar therapeutic attributes to that of Kesara . Recent studies have established standard manufacturing procedures and clinical efficacies of Kesarayukta (with Kesara ) Kuṅkumādi Ghṛta (KKG) and Nāgakesara yukta (with Nāgakesara ) Kuṅkumādi Ghṛta (NKG) in Mukhadūṣikā . In spite of wide utility of KG in Ayurvedic practice, no published work on its shelf life is available so far. To establish the physicochemical profile and evaluate the shelf life of KKG and NKG. Total three batches of KKG and NKG each were prepared in the laboratory by adopting Ayurvedic classical guidelines and the findings were systematically recorded. Comparative differences in organoleptic characters (colour, odour, taste, touch) and values of different physicochemical parameters (Ash value, pH value, Total solid content, Specific gravity, Refractive index, Loss on drying, Acid value, Iodine value, Saponification value, Peroxide value and Rancidity tests) of raw materials [herbal ingredients, Go Ghṛta , Mūrcchita Ghṛta (MG)] as well as finished products (KKG and NKG) were recorded. Long term (real time) shelf life testing was carried out at the intervals i.e., at 0, 3, 6, 9 and 16 months. High performance thin layer chromatography (HPTLC) analysis of samples was also carried out. The average percentage loss in final product was 10.18% in KKG and 7.58% in NKG. The shelf life of MG, KKG and NKG is 16 months. After 16 months, Go Ghṛta showed negative rancidity test, while MG, KKG and NKG showed positive rancidity, indicative of onset of deterioration

  19. Structural and electronic investigations of PbTa4O11 and BiTa7O19 constructed from α-U3O8 types of layers

    Science.gov (United States)

    Boltersdorf, Jonathan; Maggard, Paul A.

    2015-09-01

    The PbTa4O11 and BiTa7O19 phases were prepared by ion-exchange and solid-state methods, respectively, and their structures were characterized by neutron time-of-flight diffraction and Rietveld refinement methods (PbTa4O11, R 3 (No. 146), a=6.23700(2) Å, c=36.8613(1) Å; BiTa7O19, P 6 bar c 2 (No. 188), a=6.2197(2) Å, c=20.02981(9) Å). Their structures are comprised of layers of TaO6 octahedra surrounded by three 7-coordinate Pb(II) cations or two 8-coordinate Bi(III) cations. These layers alternate down the c-axis with α-U3O8 types of single and double TaO7 pentagonal bipyramid layers. In contrast to earlier studies, both phases are found to crystallize in noncentrosymmetric structures. Symmetry-lowering structural distortions within PbTa4O11, i.e. R 3 bar c →R3, are found to be a result of the displacement of the Ta atoms within the TaO7 and TaO6 polyhedra, towards the apical and facial oxygen atoms, respectively. In BiTa7O19, relatively lower reaction temperatures leads to an ordering of the Bi/Ta cations within a lower-symmetry structure, i.e., P63/mcm→ P 6 bar c 2 . In the absence of Bi/Ta site disorder, the Ta-O-Ta bond angles decrease and the Ta-O bond distances increase within the TaO7 double layers. Scanning electron microscopy images reveal two particle morphologies for PbTa4O11, hexagonal rods and finer irregularly-shaped particles, while BiTa7O19 forms as aggregates of irregularly-shaped particles. Electronic-structure calculations confirm the highest-energy valence band states are comprised of O 2p-orbitals and the respective Pb 6s-orbital and Bi 6s-orbital contributions. The lowest-energy conduction band states are composed of Ta 5d-orbital contributions that are delocalized over the TaO6 octahedra and layers of TaO7 pentagonal bipyramids. The symmetry-lowering distortions in the PbTa4O11 structure, and the resulting effects on its electronic structure, lead to its relatively higher photocatalytic activity compared to similar structures without

  20. Atomistic simulation of the point defects in B2-type MoTa alloy

    International Nuclear Information System (INIS)

    Zhang Jianmin; Wang Fang; Xu Kewei; Ji, Vincent

    2009-01-01

    The formation and migration mechanisms of three different point defects (mono-vacancy, anti-site defect and interstitial atom) in B 2 -type MoTa alloy have been investigated by combining molecular dynamics (MD) simulation with modified analytic embedded-atom method (MAEAM). From minimization of the formation energy, we find that the anti-site defects Mo Ta and Ta Mo are easier to form than Mo and Ta mono-vacancies, while Mo and Ta interstitial atoms are difficult to form in the alloy. In six migration mechanisms of Mo and Ta mono-vacancies, one nearest-neighbor jump (1NNJ) is the most favorable due to its lowest activation and migration energies, but it will cause a disorder in the alloy. One next-nearest-neighbor jump (1NNNJ) and one third-nearest-neighbor jump (1TNNJ) can maintain the ordered property of the alloy but require higher activation and migration energies, so the 1NNNJ and 1TNNJ should be replaced by straight [1 0 0] six nearest-neighbor cyclic jumps (S[1 0 0]6NNCJ) or bent [1 0 0] six nearest-neighbor cyclic jumps (B[1 0 0]6NNCJ) and [1 1 0] six nearest-neighbor cyclic jumps ([1 1 0]6NNCJ), respectively. Although the migrations of Mo and Ta interstitial atoms need much lower energy than Mo and Ta mono-vacancies, they are not main migration mechanisms due to difficult to form in the alloy.

  1. Moderní počítačové viry

    OpenAIRE

    Malina, Lukáš

    2008-01-01

    Bakalářská práce Moderní počítačové viry se skládá ze dvou hlavních cílů (Analýza počítačových virů a návrh zabezpečení střední počítačové sítě) rozdělených na tři části: Analýza počítačových virů, Vlastní návrh zabezpečení osobního počítače koncového uživatele (Terminálu) a Vlastní návrh zabezpečení střední počítačové sítě. V první části jsou analyzovány metody šíření a infekce, specifické vlastnosti a dopady počítačových virů na osobní počítače. V druhé části je uvedeno řešení zabezpečení o...

  2. Superconducting properties of (Nb,Ta)3Sn wires fabricated by the bronze process

    International Nuclear Information System (INIS)

    Suenaga, M.; Aihara, K.; Kaiho, K.; Luhman, T.S.

    1979-01-01

    Measurements of the superconducting critical temperature T/sub c/, critical current density, J/sub c/ (8 3 Sn monofilamentary wires. Ta content in the Nb 3 Sn compound was varied by alloying the Nb core prior to a reaction heat treatment. Core compositions were 0, 3, 7, 10, and 20 wt% Ta and heat treatments for the reaction were 16, 64, and 120 h at 725 0 C. For the 120 h heat treatment T/sub c/ decreased monotonically with Ta content from 17.5 to 15.7K while H/sub c2/ increased from 19.8 to 24.6 T. With increasing Ta content J/sub c/ (16 T) increased from 0.7 x 10 5 A/cm 2 to a maximum value of 1.3 x 10 5 at 7 wt% Ta. Further increases in the Ta content produced a decrease in J/sub c/(16 T). At 10 T J/sub c/ decreased with increasing Ta content. An important aspect of this work is the observation that alloying with Ta did not hinder wire ductility during drawing. It appears therefore that the improvements in J/sub c/(16 T) can be incorporated into commercially manufactured conductors

  3. Using the TA to Prepare Graduate Students for Research and Employment

    Science.gov (United States)

    Heller, Kenneth

    One of the most underused components of the physics graduate program is the time spent being a teaching assistant (TA). Often the TA duties consist of grading and trying to help undergraduates survive a physics course. How those duties are accomplished is left to each TA. The most common TA preparation, if it exists, has a narrow focus on the class being taught. Preparation consists of describing, or perhaps practicing, specific teaching skills and gaining familiarity with the equipment used in the laboratory portion of the class. Instead TAs can be integrated into the entire course in which they function so that they learn the course as a system. This means treating a course in the same way one approaches a research project with the TAs as members of the research team headed by a faculty advisor. TA preparation is broadened and support includes the management, teamwork, and communication skills necessary. This makes the TAs more efficient and effective teachers while explicitly connecting the TA experience to the ``soft'' skills they need in their own research careers whether in industry, national laboratories, or academia. This talk describes such a program, functioning for over 20 years at the University of Minnesota, that takes no more time than the usual TA but results in graduate students that are more satisfied with their TA experience, are better prepared to function in research groups, and provide a better classroom experience for their undergraduate students.

  4. TA 55 Reinvestment Project II Phase C Update Project Status May 23, 2017

    Energy Technology Data Exchange (ETDEWEB)

    Giordano, Anthony P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-25

    The TA-55 Reinvestment Project (TRP) II Phase C is a critical infrastructure project focused on improving safety and reliability of the Los Alamos National Laboratory (LANL) TA-55 Complex. The Project recapitalizes and revitalizes aging and obsolete facility and safety systems providing a sustainable nuclear facility for National Security Missions.

  5. "Forest Grove School District v. T.A." Supreme Court Case: Implications for School Psychology Practice

    Science.gov (United States)

    Dixon, Shauna G.; Eusebio, Eleazar C.; Turton, William J.; Wright, Peter W. D.; Hale, James B.

    2011-01-01

    The 2009 "Forest Grove School District v. T.A." United States Supreme Court case could have significant implications for school psychology practice. The Court ruled that the parents of a student with a disability were entitled to private school tuition reimbursement even though T.A. had not been identified with a disability or previously…

  6. On the ex situ and in situ doping of refractory Ta by pulsed laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Y.L.; Lin, S.S.; Shen, P. [National Sun Yat-sen University, Department of Materials and Optoelectronic Science, Kaohsiung, Taiwan (China); Chen, S. [I-Shou University, Department of Mechanical and Automation Engineering, Kaohsiung, Taiwan (China)

    2017-06-15

    Ex situ and in situ doping processes of refractory Ta were accomplished by pulsed laser ablation of bulk Ta in vacuum with C-O-H supply from C-coated collodion film and within tetraethyl orthosilicate (TEOS), respectively. Analytical electron microscopic observations of the resultant particulates and condensates indicated that the former process involved interdiffusion in the condensed state to form two kinds of core-shell structures, i.e., C-O-H doped Ta with α-type (bcc) core and lamellar shell and O-H doped γ-TaC{sub 1-x} with amorphous Ta-C-O-H surrounding, respectively, for potential wear and lubrication applications at high temperatures. In situ TEOS mediation, however, enhanced solute trapping to form Si-C-O-H overdoped α-Ta with significant tetragonality (c/a ratio up to 1.27) and Si-O-H doped γ-TaC{sub 1-x} with {111}{sub γ} twin/fault and occasional epitaxial relationship [ anti 123]{sub α}//[ anti 112]{sub γ}; (121){sub α}//(anti 11 anti 1){sub γ} due to particle coalescence. Such Si-C-O-H mediated Ta particles may have potential optocatalytic applications. (orig.)

  7. Graphite surface topography induced by Ta cluster impact and oxidative etching

    International Nuclear Information System (INIS)

    Reimann, C.T.; Olsson, L.; Erlandsson, R.; Henkel, M.; Urbassek, H.M.

    1998-01-01

    Freshly cleaved highly oriented pyrolytic graphite (HOPG), when baked in air at ∝630 C, forms one-monolayer(ML)-deep circular pits due to oxidation initiated at surface defect sites. We found that the areal density and depths of these pits could be modulated by deliberately introducing surface and sub-surface defects by energetic ion bombardment prior to baking. Bombardment by 555-eV/atom Ta 1 + , Ta 2 + , Ta 4 + , or Ta 9 + , always enhanced the areal density of etch pits, but only bombardment by Ta 4 + , or Ta 9 + significantly enhanced the depths of the pits. We performed molecular dynamics simulations of Ta n cluster bombardment of HOPG (n = 1, 2, 4, and 9) with the aim of characterizing the damage structures induced by the bombardment and correlating them with the experimental data. For Ta 9 + , the simulations showed a high level of damage extending from the surface down to nine MLs, in agreement with the most probable etch pit depth observed. For other cluster species, predicted etch pit depths were deeper than the observed ones. Annealing or steric requirements for initiating oxidation may account for some of the differences between simulations and experimental results. (orig.)

  8. Nanocrystalline β-Ta Coating Enhances the Longevity and Bioactivity of Medical Titanium Alloys

    Directory of Open Access Journals (Sweden)

    Linlin Liu

    2016-09-01

    Full Text Available A β-Ta nanocrystalline coating was engineered onto a Ti-6Al-4V substrate using a double cathode glow discharge technique to improve the corrosion resistance and bioactivity of this biomedical alloy. The new coating has a thickness of ~40 μm and exhibits a compact and homogeneous structure composed of equiaxed β-Ta grains with an average grain size of ~22 nm, which is well adhered on the substrate. Nanoindentation and scratch tests indicated that the β-Ta coating exhibited high hardness combined with good resistance to contact damage. The electrochemical behavior of the new coating was systematically investigated in Hank’s physiological solution at 37 °C. The results showed that the β-Ta coating exhibited a superior corrosion resistance as compared to uncoated Ti-6Al-4V and commercially pure tantalum, which was attributed to a stable passive film formed on the β-Ta coating. The in vitro bioactivity was studied by evaluating the apatite-forming capability of the coating after seven days of immersion in Hank’s physiological solution. The β-Ta coating showed a higher apatite-forming ability than both uncoated Ti-6Al-4V and commercially pure Ta, suggesting that the β-Ta coating has the potential to enhance functionality and increase longevity of orthopaedic implants.

  9. Flow synthesis of phenylserine using threonine aldolase (TA) immobilized on Eupergit support

    NARCIS (Netherlands)

    Tibhe, J.; Fu, Hui; Noel, T.; Wang, Q.; Meuldijk, J.; Hessel, V.

    2013-01-01

    Threonine aldolase (TA) from Thermotoga maritima was immobilized on Eupergit support by both a direct and an indirect method. The incubation time for the direct immobilization method was optimized for the highest amount of enzyme on the support. By introducing the immobilized TA in a packed-bed

  10. Overexpression of the wheat aquaporin gene, TaAQP7, enhances drought tolerance in transgenic tobacco.

    Directory of Open Access Journals (Sweden)

    Shiyi Zhou

    Full Text Available Aquaporin (AQP proteins have been shown to transport water and other small molecules through biological membranes, which is crucial for plants to combat stress caused by drought. However, the precise role of AQPs in drought stress response is not completely understood in plants. In this study, a PIP2 subgroup gene AQP, designated as TaAQP7, was cloned and characterized from wheat. Expression of TaAQP7-GFP fusion protein revealed its localization in the plasma membrane. TaAQP7 exhibited high water channel activity in Xenopus laevis oocytes and TaAQP7 transcript was induced by dehydration, and treatments with polyethylene glycol (PEG, abscisic acid (ABA and H(2O(2. Further, TaAQP7 was upregulated after PEG treatment and was blocked by inhibitors of ABA biosynthesis, implying that ABA signaling was involved in the upregulation of TaAQP7 after PEG treatment. Overexpression of TaAQP7 increased drought tolerance in tobacco. The transgenic tobacco lines had lower levels of malondialdehyde (MDA and H(2O(2, and less ion leakage (IL, but higher relative water content (RWC and superoxide dismutase (SOD and catalase (CAT activities when compared with the wild type (WT under drought stress. Taken together, our results show that TaAQP7 confers drought stress tolerance in transgenic tobacco by increasing the ability to retain water, reduce ROS accumulation and membrane damage, and enhance the activities of antioxidants.

  11. Post-Mission Assessment for Tactical Training-Trends Analysis (PMATT-TA): Usability Analysis Report

    Science.gov (United States)

    2014-07-01

    information, PMATT-TA also supports data calls to understand fleet readiness and proficiency. Additionally, PMATT-TA addresses a need for a digitally based...Software Quality Journal, 4(2), 115-130. Gray, W. D., & Salzman, M. C. (1998). Damaged merchandise ? A review of experiments that compare usability

  12. Thermal stability of TaN Schottky contacts on n-GaN

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, J.R.; Kim, D-W.; Meidia, H.; Mahajan, S

    2003-02-07

    The thermal stability and electrical characteristics of tantalum-nitrogen alloy Schottky contacts on n-GaN were investigated. Non-stoichiometric {delta}-phase (40 atomic percent nitrogen) tantalum nitride contacts exhibited good electrical properties up to an annealing temperature of 600 deg. C. However, they degrade rapidly above this temperature due to outward diffusion of Ga and presumably nitrogen into the {delta}-phase tantalum nitride. It is surmised that excess Ta reacts with N at the GaN surface, freeing Ga which then diffuses into the TaN layer. Stoichiometric TaN Schottky contacts were stable at temperatures as high as 800 deg. C and had far superior electrical performance. This stems from the thermodynamic stability of the stoichiometric TaN/GaN interface. {delta}-phase TaN had I-V and C-V barrier heights of 0.55 eV and 0.8 eV respectively. On the other hand, TaN had an I-V barrier height near 0.7 eV and a C-V barrier height near 1.2 eV. The ideality factors for both {delta}-phase TaN and TaN were above 1.8 at all annealing temperatures, suggesting tunneling contributes significantly to current transport.

  13. Confronting passive behavior through outdoor experience: a TA approach to experiential learning

    Science.gov (United States)

    Frederick W. Medrick

    1977-01-01

    The concepts and techniques of transactional analysis (TA) can usefully be applied to outdoor challenge programs aimed at facilitating personal growth, developing responsibility, and teaching cooperative behavior. Passive behavior results from discounting of the self and others; four levels of it have been identified, and TA offers various means of preventing or...

  14. Suboxide/subnitride formation on Ta masks during magnetic material etching by reactive plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hu; Muraki, Yu; Karahashi, Kazuhiro; Hamaguchi, Satoshi, E-mail: hamaguch@ppl.eng.osaka-u.ac.jp [Center for Atomic and Molecular Technologies, Osaka University, Yamadaoka 2-1, Suita 565-0871 (Japan)

    2015-07-15

    Etching characteristics of tantalum (Ta) masks used in magnetoresistive random-access memory etching processes by carbon monoxide and ammonium (CO/NH{sub 3}) or methanol (CH{sub 3}OH) plasmas have been examined by mass-selected ion beam experiments with in-situ surface analyses. It has been suggested in earlier studies that etching of magnetic materials, i.e., Fe, Ni, Co, and their alloys, by such plasmas is mostly due to physical sputtering and etch selectivity of the process arises from etch resistance (i.e., low-sputtering yield) of the hard mask materials such as Ta. In this study, it is shown that, during Ta etching by energetic CO{sup +} or N{sup +} ions, suboxides or subnitrides are formed on the Ta surface, which reduces the apparent sputtering yield of Ta. It is also shown that the sputtering yield of Ta by energetic CO{sup +} or N{sup +} ions has a strong dependence on the angle of ion incidence, which suggests a correlation between the sputtering yield and the oxidation states of Ta in the suboxide or subnitride; the higher the oxidation state of Ta, the lower is the sputtering yield. These data account for the observed etch selectivity by CO/NH{sub 3} and CH{sub 3}OH plasmas.

  15. Wheat Transcription Factor TaAREB3 Participates in Drought and Freezing Tolerances in Arabidopsis.

    Science.gov (United States)

    Wang, Jingyi; Li, Qian; Mao, Xinguo; Li, Ang; Jing, Ruilian

    2016-01-01

    AREB (ABA response element binding) proteins in plants play direct regulatory roles in response to multiple stresses, but their functions in wheat (Triticum aestivum L.) are not clear. In the present study, TaAREB3, a new member of the AREB transcription factor family, was isolated from wheat. Sequence analysis showed that the TaAREB3 protein is composed of three parts, a conserved N-terminal, a variable M region, and a conserved C-terminal with a bZIP domain. It belongs to the group A subfamily of bZIP transcription factors. TaAREB3 was constitutively expressed in stems, leaves, florets, anthers, pistils, seeds, and most highly, in roots. TaAREB3 gene expression was induced with abscisic acid (ABA) and low temperature stress, and its protein was localized in the nucleus when transiently expressed in tobacco epidermal cells and stably expressed in transgenic Arabidopsis. TaAREB3 protein has transcriptional activation activity, and can bind to the ABRE cis-element in vitro. Overexpression of TaAREB3 in Arabidopsis not only enhanced ABA sensitivity, but also strengthened drought and freezing tolerances. TaAREB3 also activated RD29A, RD29B, COR15A, and COR47 by binding to their promoter regions in transgenic Arabidopsis. These results demonstrated that TaAREB3 plays an important role in drought and freezing tolerances in Arabidopsis.

  16. Multipacting Simulations of Tuner-adjustable waveguide coupler (TaCo) with CST

    CERN Document Server

    Shafqat, Nuaman; Wegner, Rolf

    2015-01-01

    Tuner-adjustable waveguide couplers (TaCo) are used to feed microwave power to different RF structures of LINAC4. This paper studies the multipacting phenomenon for TaCo using PIC solver of CST PS. Simulations are performed for complete field sweeps and results are analysed.

  17. Evaluation of the potential for surface faulting at TA-63. Final report

    International Nuclear Information System (INIS)

    Kolbe, T.; Sawyer, J.; Springer, J.; Olig, S.; Hemphill-Haley, M.; Wong, I.; Reneau, S.

    1995-01-01

    This report describes an investigation of the potential for surface faulting at the proposed sites for the Radioactive Liquid Waste Treatment Facility (RL)WF) and the Hazardous Waste Treatment Facility at TA-63 and TA-52 (hereafter TA-63), Los Alamos National Laboratory (LANL). This study was performed by Woodward-Clyde Federal Services (WCFS) at the request of the LANL. The projections of both the Guaje Mountain and Rendija Canyon faults are mapped in the vicinity of TA-63. Based on results obtained in the ongoing Seismic Hazard Evaluation Program of the LANL, displacement may have occurred on both the Guaje Mountain and Rendija Canyon faults in the past 11,000 years (Holocene time). Thus, in accordance with US Department of Energy (DOE) Orders and Standards for seismic hazards evaluations and the US Environmental Protection Agency (EPA) Resource Conservation and Recovery Act (RCRA) Regulations for seismic standard requirements, a geologic study of the proposed TA-63 site was conducted

  18. Function of the auxin-responsive gene TaSAUR75 under salt and drought stress

    Directory of Open Access Journals (Sweden)

    Yuan Guo

    2018-04-01

    Full Text Available Small auxin-upregulated RNAs (SAURs are genes regulated by auxin and environmental factors. In this study, we identified a SAUR gene in wheat, TaSAUR75. Under salt stress, TaSAUR75 is downregulated in wheat roots. Subcellular localization revealed that TaSAUR75 was localized in both the cytoplasm and nucleus. Overexpression of TaSAUR75 increased drought and salt tolerance in Arabidopsis. Transgenic lines showed higher root length and survival rate and higher expression of some stress-responsive genes than control plants under salt and drought stress. Less H2O2 accumulated in transgenic lines than in control plants under drought stress. Our findings reveal a positive regulatory role of the auxin-responsive gene TaSAUR75 in plant responses to drought and salt stress and provide a candidate gene for improvement of abiotic stress tolerance in crop breeding.

  19. The preferential orientation and lattice misfit of the directionally solidified Fe-Al-Ta eutectic composite

    Science.gov (United States)

    Cui, Chunjuan; Wang, Pei; Yang, Meng; Wen, Yagang; Ren, Chiqiang; Wang, Songyuan

    2018-01-01

    Fe-Al intermetallic compound has been paid more attentions recently in many fields such as aeronautic, aerospace, automobile, energy and chemical engineering, and so on. In this paper Fe-Al-Ta eutectic was prepared by a modified Bridgman directional solidification technique, and it is found that microstructure of the Fe-Al-Ta eutectic alloy transforms from the broken-lamellar eutectic to cellular eutectic with the increase of the solidification rate. In the cellular eutectic structure, the fibers are parallel to each other within the same grain, but some fibers are deviated from the original orientation at the grain boundaries. To study the crystallographic orientation relationship (OR) between the two phases, the preferential orientation of the Fe-Al-Ta eutectic alloy at the different solidification rates was studied by Selected Area Electron Diffraction (SAED). Moreover, the lattice misfit between Fe2Ta(Al) Laves phase and Fe(Al,Ta) matrix phase was calculated.

  20. Ta(CNDipp){sub 6}. An isocyanide analogue of hexacarbonyltantalum(0)

    Energy Technology Data Exchange (ETDEWEB)

    Chakarawet, Khetpakorn; Long, Jeffrey R. [Department of Chemistry, University of California, Berkeley, CA (United States); Davis-Gilbert, Zachary W.; Harstad, Stephanie R.; Young, Victor G. Jr.; Ellis, John E. [Department of Chemistry, University of Minnesota, Minneapolis, MN (United States)

    2017-08-21

    Hexakis(2,6-diisopropylphenylisocyanide)tantalum is the first isocyanide analogue of the highly unstable Ta(CO){sub 6} and represents the only well-defined zerovalent tantalum complex to be prepared by conventional laboratory methods. Two prior examples of homoleptic Ta{sup 0} complexes are known, Ta(benzene){sub 2} and Ta(dmpe){sub 3}, dmpe=1,2-bis(dimethylphosphano)ethane, but these have only been accessed via ligand co-condensation with tantalum vapor in a sophisticated metal-atom reactor. Consistent with its 17-electron nature, Ta(CNDipp){sub 6} undergoes facile one-electron oxidation, reduction, or disproportionation reactions. In this sense, it qualitatively resembles V(CO){sub 6}, the only paramagnetic homoleptic metal carbonyl isolable under ambient conditions. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Electron radiation defects in TaCsub(1-x) and TiCsub(0.97)

    International Nuclear Information System (INIS)

    Morillo, J.; Novion, C.H. de; Dural, J.

    1981-08-01

    The electrical resistivity changes of TaCsub(0.99) and TaCsub(0.80) have been measured at 21 K during irradiation with electrons of incident energies ranging from 2.5 to 0.25 MeV: a non-zero production rate is observed, even at the lowest energies. The recovery of defects was followed up to 400 K for TaCsub(0.99) and TiCsub(0.97) irradiated with 2.25 MeV electrons and up to 160 K for TaCsub(0.80) irradiated with 0.75 MeV electrons. The results are compared to fast neutron radiation damage data. For TiCsub(0.97) and TaCsub(0.99), the contributions of the different defects to the production rates and recovery spectra are tentatively separated, and a rough estimate of Frenkel pair resistivities is given

  2. Lithium-ion storage capacitors achieved by CVD graphene/TaC/Ta-wires and carbon hollow spheres

    International Nuclear Information System (INIS)

    Zhao, Liwei; Li, Hongji; Li, Mingji; Xu, Sheng; Li, Cuiping; Qu, Changqing; Zhang, Lijun; Yang, Baohe

    2016-01-01

    Highlights: • Graphene/TaC/Ta wire electrode was prepared by CVD. • Carbon hollow spheres as a solid electrolyte were prepared by hydrothermal. • Specific capacitance of assembled capacitor reached 593 F g −1 at 10 A g −1 . • The capacitor provided high energy and power densities (132 W h kg −1 /3.17 kW kg −1 ). • The hybrid capacitor also exhibited a high stability during long endurance tests. - Abstract: Lithium-ion storage capacitors were assembled using graphene/tantalum carbide/tantalum wire electrodes and carbon hollow spheres as electrolyte. The graphene/tantalum carbide layers were prepared by electron-assisted hot filament chemical vapor deposition; the carbon hollow spheres were synthesized by hydrothermal reaction and pyrolysis treatment. The specific capacitance of the capacitor was 593 F g −1 at a current density of 10 A g −1 . The capacitor showed excellent cycling stability, retaining 91.2% of its initial capacitance after 8000 cycles. Moreover, the capacitor provided a high specific energy density of 132 W h kg −1 at a high power density of 3.17 kW kg −1 . The high energy density is attributed to the widened operation window ranging from 0 to 3.0 V. The graphene layer of the electrode and carbon hollow spheres in electrolyte synergistic affect influence on the electrochemical performance of the capacitor are discussed. In addition, the use of a low-cost lithium salt, lithium chloride, is also featured in this paper.

  3. Suppression of wheat TaCDK8/TaWIN1 interaction negatively affects germination of Blumeria graminis f.sp. tritici by interfering with very-long-chain aldehyde biosynthesis.

    Science.gov (United States)

    Kong, Lingyao; Chang, Cheng

    2018-01-01

    Wheat TaCDK8 interacts with TaWIN1 to regulate very-long-chain aldehyde biosynthesis required for efficient germination of Blumeria graminis f.sp. tritici. Powdery mildew caused by Blumeria graminis f.sp. tritici (Bgt) is a devastating disease of common wheat (Triticum aestivum L.). Bgt infection initiates with its conidia germination on the aerial surface of wheat. In this study, we isolated the cyclin-dependent kinase 8 (TaCDK8) from wheat cultivar Jing411 and found that silencing of TaCDK8 impeded Bgt germination. The biochemical and molecular-biological assays revealed that TaCDK8 interacts with and phosphorylates the wheat transcription factor wax inducer 1 (TaWIN1) to stimulate the TaWIN1-dependent transcription. Bgt conidia on the leaves of TaWIN1-silenced plants also showed reduced germination. Gas chromatographic analysis revealed that knockdown of TaCDK8 or TaWIN1 resulted in decreases of wax components and cutin monomers in wheat leaves. Moreover, Bgt germination on leaves of TaCDK8 or TaWIN1 silenced plants could be fully restored by application of wild-type cuticular wax. In vitro studies demonstrated that very-long-chain aldehydes absent from the cuticular wax of the TaCDK8 or TaWIN1 silenced plants were capable of chemically stimulating Bgt germination. These results implicated that the suppression of TaCDK8/TaWIN1 interaction negatively affects Bgt germination by interfering with very-long-chain aldehyde biosynthesis required for efficient fungal germination.

  4. Particle size dependence on oxygen reduction reaction activity of electrodeposited TaOx catalysts in acidic media

    KAUST Repository

    Seo, J.; Cha, Dong Kyu; Takanabe, Kazuhiro; Kubota, J.; Domen, K.

    2013-01-01

    The size dependence of the oxygen reduction reaction activity was studied for TaOx nanoparticles electrodeposited on carbon black for application to polymer electrolyte fuel cells (PEFCs). Compared with a commercial Ta2O5 material, the ultrafine

  5. 77 FR 47671 - TA-W-81,520, T-Mobile USA, Inc., Call Center, Allentown, PA; TA-W-81,520G, T-Mobile USA, Inc...

    Science.gov (United States)

    2012-08-09

    ... DEPARTMENT OF LABOR Employment and Training Administration TA-W-81,520, T-Mobile USA, Inc., Call Center, Allentown, PA; TA- W-81,520G, T-Mobile USA, Inc., Headquarters Office, Bellevue, WA; Amended... of T-Mobile USA, Inc., Call Center, Allentown, Pennsylvania (TA-W-81,520), Fort Lauderdale, Florida...

  6. Scanning tunneling microscopy of atoms and charge density waves in 1T-TaS2, 1T-TaSe2 and 1T-VSe2

    International Nuclear Information System (INIS)

    Slough, G.; Giambattista, B.; Johnson, A.; McNairy, W.W.; Coleman, R.V.

    1988-01-01

    The layer structure dichalcogenide materials TaS 2 and TaSe 2 grow in several different phases depending on the coordination between the Ta and chalcogenide atoms and the number of three layer sandwiches per unit cell. The 1T phase has octahedral coordination between the Ta and chalcogenide atoms and has one three layer sandwich per unit cell. The high temperature Fermi surfaces (FSs) of the 1T phase Ta based materials exhibit a favorable nesting condition and undergo a charge-density-wave (CDW) transition at temperatures well above room temperature. At low temperatures the CDWs form a √13 /ovr string/a /times/ √13 a commensurate superlattice. STM scans on the 1T phases confirm the presence of an extremely strong CDW modulation inducing z-deflections in the constant current mode of anomalously large values. 1T-VSe 2 is also a member of the VB layer structure dichalcogenide group and band structure calculations show the high temperatures FS to be similar to that of 1T-TaSe 2 . However, sufficient differences exist such that the CDW formation is quite different. The CDW superlattice is observed to form only below room temperature and locks into a 4/ovr string/a /times/ 4/ovr string/a superlattice below /approximately/80K rather than the √13 /ovr string/a /times/ √13 /ovr string/a one observed in 1T-TaSe 2 . Based on electron and neutron diffraction results on stoichiometric 1T-VSe 2 two phase transitions are detected, a second order transition at 110K and a first order transition at /approximately/80K. 20 figs

  7. Efeito de diferentes substratos e épocas de coleta no enraizamento de estacas herbáceas de goiabeira, cvs. paluma e século XXI Effect of different substrates and collection seasons on the herbaceous cuttings rooting of guava, cvs. paluma and século XXI

    Directory of Open Access Journals (Sweden)

    Corina Zietemann

    2007-04-01

    Full Text Available Este trabalho objetivou avaliar o enraizamento de estacas herbáceas das goiabeiras 'Paluma' e 'Século XXI' em diferentes substratos, coletadas na primavera e no verão. As estacas foram obtidas de ramos jovens não-lignificados de árvores de quatro anos, com um par de folhas no nó superior e 10 cm de comprimento. Para cada época testada, as estacas foram tratadas por imersão rápida, com cinco doses de AIB (0; 500; 1.000; 1.500 e 2.000 mg/L e dispostas em bandejas plásticas perfuradas com dois substratos (casca de arroz carbonizada e vermiculita em câmara de nebulização. Após 70 dias da estaquia, foram avaliadas as seguintes variáveis: porcentagem de enraizamento; massas seca e fresca das raízes; número de raízes por estaca; comprimento das raízes; sobrevivência; retenção foliar e porcentagem de estacas com calo. Concluiu-se que houve maior enraizamento das estacas coletadas no verão e que as doses de 1.500 e 2.000 mg/L de AIB são as mais adequadas para promover as melhores características de enraizamento das estacas para as cvs. Paluma e Século XXI, respectivamente. Os dois substratos utilizados são indicados para a estaquia das goiabeiras estudadas.The objective of this research was to evaluate the influence of different substrates and collection season on the herbaceous cutting rooting of 'Paluma' and 'Século XXI' guava plants (Psidium guajava L.. The herbaceous cuttings were obtained on spring and summer seasons, consisted of 10cm of length, two nodes and a pair of leaves in the superior node, and treated with five doses of IBA (0, 500, 1,500 and 2,000 mg/L for each season studied, and disposed into plastic boxes containing hull rice coal and vermiculita as substrates. After 70 days, the rooting percentage, roots length, number of roots, fresh and dry matter of roots, survival percentage, foliar retention and percentage of cuttings with callus were evaluated. The results showed that the better rooting percentage

  8. COMPORTAMENTO FISIOLÓGICO IN VITRO DE BANANEIRA (Musa sp., AAA e AAB cvs. NANICA E PRATA ANÃ: INFLUÊNCIA DE DIFERENTES NÍVEIS DE POTÁSSIO PYSIOLOGICAL BEHAVIOR OF BANANA (Musa sp., AAA and AAB cvs. 'NANICA' AND 'PRATA ANÃ' IN VITRO CONDITION: INFLUENCE OF DIFFERENT LEVELS OF POTASSIUM

    Directory of Open Access Journals (Sweden)

    Humberto Actis Zaidan

    1999-01-01

    Full Text Available Nas abordagens biotecnológicas de propagação de plantas, os meios de cultura devem ter uma composição química adequada à essa finalidade permitindo a otimização da produção. Como a bananeira (Musa sp. é exigente em potássio, a busca do nível adequado desse macronutriente envolve não somente o comprometimento com o nível dos outros nutrientes (balanço iônico, mas também a relação entre eles. Para acompanhar os efeitos fisiológicos dos vários teores de K, explantes caulinares dos cvs. "Nanica" e "Prata Anã" foram cultivados em meio MS modificado, em presença de BAP (2,5 mg/L, sacarose, vitaminas e agar, em seis diferentes concentrações de K: 5, 10, 15, 20, 25 e 30 mM, sendo 20 mM a concentração de K no MS básico. Foram feitas análises de massa de matéria seca (MMS, K na parte aérea, raiz e plântulas inteiras, e determinado o número de plântulas, aos 90 dias de idade. Após início de cultivo todos os parâmetros foram analisados segundo um delineamento inteiramente casualizado. As plântulas que se desenvolveram em baixas concentrações de K apresentaram sintomas visuais de deficiência de K, como clorose e necrose nas folhas mais velhas. Os cultivares apresentaram diferenças quantitativas entre si, relacionados à concentração de K presente no meio de cultura, seja em relação aos valores de MMS, ou quanto ao número de plântulas formadas. Em ambos os cultivares, foi observada uma relação direta entre o desenvolvimento de plântulas e as concentrações de K com otimização ao redor de 15 a 20 mM de K.The chemical composition of culture growth media to micropropagate plants should be devised to allow the best quality and high production of plant material. One of the challenges is to optimize the ionic balance involving mineral nutrients. As banana (Musa sp. requires high levels of potassium, the optimum level was investigated. Shoot apexes of two banana cultivars 'Nanica' and 'Prata Anã' were

  9. Interfacial scattering effect on anisotropic magnetoresistance and anomalous Hall effect in Ta/Fe multilayers

    KAUST Repository

    Zhang, Qiang

    2017-12-26

    The effect of interfacial scattering on anisotropic magnetoresistance (AMR) and anomalous Hall effect (AHE) was studied in the (Ta12n/Fe36n)n multilayers, where the numbers give the thickness in nanometer and n is an integer from 1 to 12. The multilayer structure has been confirmed by the XRR spectra and STEM images of cross-sections. The magneto-transport properties were measured by four-point probe method in Hall bar shaped samples in the temperature range of 5 - 300 K. The AMR increases with n, which could be ascribed to the interfacial spin-orbit scattering. At 5 K, the longitudinal resistivity (ρ) increases by 6.4 times and the anomalous Hall resistivity (ρ) increases by 49.4 times from n =1 to n =12, indicative of the interfacial scattering effect. The skew-scattering, side-jump and intrinsic contributions to the AHE were separated successfully. As n increases from 1 to 12, the intrinsic contribution decreases because of the decaying crystallinity or finite size effect and the intrinsic contribution dominated the AHE for all samples. The side jump changes from negative to positive because the interfacial scattering and intralayer scattering in Fe layers both contribute to side jump in the AHE but with opposite sign.

  10. The high-flux effect on deuterium retention in TiC and TaC doped tungsten at high temperatures

    Science.gov (United States)

    Zibrov, Mikhail; Bystrov, Kirill; Mayer, Matej; Morgan, Thomas W.; Kurishita, Hiroaki

    2017-10-01

    Samples made of tungsten (W) doped either with titanium carbide (W-1.1TiC) or tantalum carbide (W-3.3TaC) were exposed to a low-energy (40 eV/D), high-flux (1.8-5 × 1023 D/m2s) deuterium (D) plasma at temperatures of about800 K, 1050 K, and 1250 K to a fluence of about1 × 1027 D/m2. The deuterium (D) inventory in the samples was examined by nuclear reaction analysis and thermal desorption spectroscopy. At 800 K the D bulk concentrations and total D inventories in W-1.1TiC and W-3.3TaC were more than one order of magnitude higher compared to that in pure polycrystalline W. At 1050 K and 1250 K the D concentrations in all types of samples were very low (≤10-5 at. fr.); however the D inventories in W-1.1TiC were significantly higher compared to those in W-3.3TaC and pure W. It is suggested that D trapping inside the carbide precipitates and at their boundaries is essential at high temperatures and high incident fluxes, especially in W-1.1TiC.

  11. Highly dispersed TaOx nanoparticles prepared by electrodeposition as oxygen reduction electrocatalysts for polymer electrolyte fuel cells

    KAUST Repository

    Seo, Jeongsuk; Zhao, Lan; Cha, Dong Kyu; Takanabe, Kazuhiro; Katayama, Masao; Kubota, Jun; Domen, Kazunari

    2013-01-01

    for the oxygen reduction reaction (ORR) in polymer electrolyte fuel cells (PEFCs). Electrodeposition conditions of Ta complexes and subsequent various heat treatments for the deposited TaOx were examined for the best performance of the ORR. TaOx particles

  12. 78 FR 41954 - TA-W-82,634, Prudential Global Business Technology Solutions Central Security Services Dresher...

    Science.gov (United States)

    2013-07-12

    ... Business Technology Solutions Central Security Services Iselin, New Jersey; TA-W-82,634B, Prudential Global Business Technology Solutions Central Security Services Plymouth, Minnesota; TA- W-82,634C, Prudential Global Business Technology Solutions Central Security Services Scottsdale, Arizona; TA-W-82,634D...

  13. 77 FR 42003 - TA-W-81,263, Chartis Global Services, Inc., a Subsidiary of Chartis, Inc., Regional Processing...

    Science.gov (United States)

    2012-07-17

    ... DEPARTMENT OF LABOR Employment and Training Administration TA-W-81,263, Chartis Global Services..., Houston, TX; TA-W-81,263A, Chartis Global Services, Inc., a Subsidiary of Chartis, Inc., Regional... is amending the certification (TA-W-81,263) to add ``Regional Processing Organization'' and to add...

  14. Promising Ta-Ti-Zr-Si metallic glass coating without cytotoxic elements for bio-implant applications

    Science.gov (United States)

    Lai, J. J.; Lin, Y. S.; Chang, C. H.; Wei, T. Y.; Huang, J. C.; Liao, Z. X.; Lin, C. H.; Chen, C. H.

    2018-01-01

    Tantalum (Ta) is considered as one of the most promising metal due to its high corrosion resistance, excellent biocompatibility and cell adhesion/in-growth capabilities. Although there are some researches exploring the biomedical aspects of Ta and Ta based alloys, systematic characterizations of newly developed Ta-based metallic glasses in bio-implant applications is still lacking. This study employs sputtering approach to produced thin-film Ti-based metallic glasses due to the high melting temperature of Ta (3020 °C). Two fully amorphous Ta-based metallic glasses composed of Ta57Ti17Zr15Si11 and Ta75Ti10Zr8Si7 are produced and experimentally characterized in terms of their mechanical properties, bio-corrosion properties, surface hydrophilic characteristics, and in-vitro cell viability and cells attachment tests. Compare to conventional pure Ti and Ta metals, the developed Ta-based metallic glasses exhibit higher hardness and lower modulus which are better match to the mechanical properties of bone. MTS assay results show that Ta-based metallic glasses show comparable cell viability and cell attachment rate compared to that of pure Ti and Ta surface in a 72 h in-vitro test.

  15. Unconstrained Enhanced Sampling for Free Energy Calculations of Biomolecules: A Review

    Science.gov (United States)

    Miao, Yinglong; McCammon, J. Andrew

    2016-01-01

    Free energy calculations are central to understanding the structure, dynamics and function of biomolecules. Yet insufficient sampling of biomolecular configurations is often regarded as one of the main sources of error. Many enhanced sampling techniques have been developed to address this issue. Notably, enhanced sampling methods based on biasing collective variables (CVs), including the widely used umbrella sampling, adaptive biasing force and metadynamics, have been discussed in a recent excellent review (Abrams and Bussi, Entropy, 2014). Here, we aim to review enhanced sampling methods that do not require predefined system-dependent CVs for biomolecular simulations and as such do not suffer from the hidden energy barrier problem as encountered in the CV-biasing methods. These methods include, but are not limited to, replica exchange/parallel tempering, self-guided molecular/Langevin dynamics, essential energy space random walk and accelerated molecular dynamics. While it is overwhelming to describe all details of each method, we provide a summary of the methods along with the applications and offer our perspectives. We conclude with challenges and prospects of the unconstrained enhanced sampling methods for accurate biomolecular free energy calculations. PMID:27453631

  16. Mechanism of n-butane hydrogenolysis promoted by Ta-hydrides supported on silica

    KAUST Repository

    Pasha, Farhan Ahmad

    2014-06-06

    The mechanism of hydrogenolysis of alkanes, promoted by Ta-hydrides supported on silica via 2 ≡ Si-O- bonds, has been studied with a density functional theory (DFT) approach. Our study suggests that the initial monohydride (≡ Si-O-)2Ta(III)H is rapidly trapped by molecular hydrogen to form the more stable tris-hydride (≡ Si-O-) 2Ta(V)H3. Loading of n-butane to the Ta-center occurs through C-H activation concerted with elimination of molecular hydrogen (σ-bond metathesis). Once the Ta-alkyl species is formed, the C-C activation step corresponds to a β-alkyl transfer to the metal with elimination of an olefin. According to these calculations, an α-alkyl transfer to the metal to form a Ta-carbene species is of higher energy. The olefins formed during the C-C activation step can be rapidly hydrogenated by both mono- and tris-Ta-hydride species, making the overall process of alkane cracking thermodynamically favored. © 2014 American Chemical Society.

  17. Structures of Ta22W4O67 and Ta74W6O203. Pt. 1. Refined structural models using synchrotron radiation

    International Nuclear Information System (INIS)

    Schmid, S.

    1995-01-01

    The crystal structures of Ta 22 W 4 O 67 [M r = 5788.19, a = 6.1485 (5), b = 47.6205 (12), c = 3.8559 (3) A, γ = 90.04 (1) , space group = C112/m (non-standard setting), Z = 1, D x = 8.513 g cm -3 , F(000) = 2438] and Ta 74 W 6 O 203 [M r = 17741.06, a = 6.1664 (5), b = 29.2717 (14), c = 3.8731 (2) A, space group = Pbam (no. 55), Z = 0.2, D x = 8.428 g cm -3 , F(000) 1494] were determined using synchrotron radiation at four different wavelengths below the Ta L III edge [λ = 1.2741 (-146 eV), λ = 1.2586 (-26 eV), λ = 1.2571 (-14 eV) and λ = 1.2563 A (-8 eV)]. The collection of data immediately below the Ta L III edge at -8 eV enabled resolution of Ta and W of up to eight electrons, which assisted in the refinement of Ta/W ordering for both structures. Bond valence arguments have been used to locate oxygen vacancies required by the formulae. From the largest data set for Ta 22 W 4 O 67 (λ = 1.2741 A), a final value of 0.0481 for R 1 = Σ parallel F obs (h)vertical stroke - vertical stroke F calc (h) parallel /Σvertical stroke F obs (h)vertical stroke was obtained for 3082 unmerged reflections with I(h) > 3σ[I(h)] and for Ta 74 W 6 O 203 (λ = 1.2563 A) a final value of 0.0571 for R 1 was obtained for 5675 unmerged reflections. The two structures are described from a conventional polyhedral perspective as 13- and 8-times superstructures occurring in the solid solution (1-x)Ta 2 O 5 xWO 3 , 0 ≤ x ≤ 0.267. (orig.)

  18. Thickness-dependent enhancement of damping in C o2FeAl /β -Ta thin films

    Science.gov (United States)

    Akansel, Serkan; Kumar, Ankit; Behera, Nilamani; Husain, Sajid; Brucas, Rimantas; Chaudhary, Sujeet; Svedlindh, Peter

    2018-04-01

    In the present work C o2FeAl (CFA) thin films were deposited by ion beam sputtering on Si (100) substrates at the optimized deposition temperature of 300 °C. A series of CFA films with different thicknesses (tCFA), 8, 10, 12, 14, 16, 18, and 20 nm, were prepared and all samples were capped with a 5-nm-thick β-Ta layer. The thickness-dependent static and dynamic properties of the films were studied by SQUID magnetometry, in-plane as well as out-of-plane broadband vector network analyzer-ferromagnetic resonance (FMR) measurements, and angle-dependent cavity FMR measurements. The saturation magnetization and the coercive field were found to be weakly thickness dependent and lie in the range 900-950 kA/m and 0.53-0.87 kA/m, respectively. The effective damping parameter (αeff) extracted from in-plane and out-of-plane FMR results reveals a 1/tCFA dependence, the values for the in-plane αeff being larger due to two-magnon scattering (TMS). The origin of the αeff thickness dependence is spin pumping into the nonmagnetic β-Ta layer and in the case of the in-plane αeff, also a thickness-dependent TMS contribution. From the out-of-plane FMR results, it was possible to disentangle the different contributions to αeff and to the extract values for the intrinsic Gilbert damping (αG) and the effective spin-mixing conductance (geff↑↓) of the CFA/ β-Ta interface, yielding αG=(1.1 ±0.2 ) ×10-3 and geff↑↓=(2.90 ±0.10 ) ×1019m-2 .

  19. SEMICONDUCTOR TECHNOLOGY: TaN wet etch for application in dual-metal-gate integration technology

    Science.gov (United States)

    Yongliang, Li; Qiuxia, Xu

    2009-12-01

    Wet-etch etchants and the TaN film method for dual-metal-gate integration are investigated. Both HF/HN O3/H2O and NH4OH/H2O2 solutions can etch TaN effectively, but poor selectivity to the gate dielectric for the HF/HNO3/H2O solution due to HF being included in HF/HNO3/H2O, and the fact that TaN is difficult to etch in the NH4OH/H2O2 solution at the first stage due to the thin TaOxNy layer on the TaN surface, mean that they are difficult to individually apply to dual-metal-gate integration. A two-step wet etching strategy using the HF/HNO3/H2O solution first and the NH4OH/H2O2 solution later can fully remove thin TaN film with a photo-resist mask and has high selectivity to the HfSiON dielectric film underneath. High-k dielectric film surfaces are smooth after wet etching of the TaN metal gate and MOSCAPs show well-behaved C-V and Jg-Vg characteristics, which all prove that the wet etching of TaN has little impact on electrical performance and can be applied to dual-metal-gate integration technology for removing the first TaN metal gate in the PMOS region.

  20. TaSiN nanocomposite thin films: Correlation between structure, chemical composition, and physical properties

    International Nuclear Information System (INIS)

    Ramírez, G.; Oezer, D.; Rivera, M.; Rodil, S.E.; Sanjinés, R.

    2014-01-01

    The structural and electronic properties of fcc-TaN/SiN x nanocomposite thin films deposited by reactive magnetron sputtering have been investigated as function of the N and Si contents. Our studies have been mainly focused on three different types of nanocomposite Ta x Si y N z films based on: nitrogen deficient fcc-TaN 0.88 , nearly stoichiometric fcc-TaN, and over-stoichiometric fcc-TaN 1.2 with the Si contents in the range from 0 to about 15 at.%. The optical properties were investigated by ellipsometric measurements, while the DC. electrical resistivity was measured using the van der Pauw configuration at 300 K. The optical measurements were interpreted using the standard Drude–Lorentz model. The results showed that the electronic properties are closely correlated with both the compositional and the structural modifications of the Ta x Si y N z films induced by the addition of Si atoms, and also depending on the stoichiometry of the starting fcc-TaN system. Thus, depending on both the nitrogen and the silicon contents, the fcc-Ta x Si y N z films can exhibit room temperature resistivity values ranging from 10 2 μΩ cm to about 6 × 10 4 μΩ cm. - Highlights: • TaSiN films were grown using dual magnetron sputtering system. • The physical and structural properties were correlated with the deposition parameters. • The electrical properties were influenced by the nitrogen and silicon contents on the films

  1. The structure of Ta nanopillars grown by glancing angle deposition

    International Nuclear Information System (INIS)

    Zhou, C.M.; Gall, D.

    2006-01-01

    Regular arrays of Ta nanopillars, 200 nm wide and 500 nm tall, were grown on SiO 2 nanosphere patterns by glancing angle sputter deposition (GLAD). Plan-view and cross-sectional scanning electron microscopy analyses show dramatic changes in the structure and morphology of individual nanopillars as a function of growth temperature T s ranging from 200 to 700 deg. C. At low temperatures, T s ≤ 300 deg. C, single nanopillars develop on each sphere and branch into subpillars near the pillar top. In contrast, T s ≥ 500 deg. C leads to branching during the nucleation stage at the pillar bottom. The top branching at low T s is associated with surface mounds on a growing pillar that, due to atomic shadowing, develop into separated subpillars. At high T s , the branching occurs during the nucleation stage where multiple nuclei on a single SiO 2 sphere develop into subpillars during a competitive growth mode which, in turn, leads to intercolumnar competition and the extinction of some nanopillars

  2. LAFD: TA-55 General Facility Familiarization Tour, Course #55261

    Energy Technology Data Exchange (ETDEWEB)

    Rutherford, Victor Stephen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Miller, Joshua [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mason, Robert Clifford [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2018-01-10

    Los Alamos National Laboratory (LANL) will conduct familiarization tours for personnel of the Los Alamos County Fire Department (LAFD) at the TA-55 General Facility. These familiarization tours are official LANL business; the purpose of these tours is to orient LAFD firefighters to the facility so that they can respond efficiently and quickly to a variety of emergency situations. This orientation includes, among other topics, ingress and egress of the area and buildings, layout and organization of the facility, evacuation procedures and assembly points, and areas of concern within the various buildings at the facility. LAFD firefighters have the skills and abilities to perform firefighting operations and other emergency response tasks that cannot be provided by LANL personnel who have the required clearance level. This handout provides details of the information, along with maps and diagrams, to be presented during the familiarization tours. The handout will be distributed to the trainees at the time of the tour. A corresponding checklist will also be used as guidance during the familiarization tours to ensure that all required information is presented to LAFD personnel.

  3. Bitcoin - alternatīva valūta

    OpenAIRE

    Liškovska, Eva

    2014-01-01

    Mūsdienās digitālās valūtas kļūst ar vien izplatītākas, tādēļ autore ir izvēlējusies pētīt digitālo valūtu Bitcoin. Maģistra darba mērķis ir izanalizēt, kādas ir Bitcoin valūtas priekšrocības un trūkumi, lai izdarītu secinājumus un izstrādātu priekšlikumus Bitcoin uzlabošanai, lai nākotnē tā spētu būt tikpat konkurētspējīga kā reālā valūta. Pēc pētījuma veikšanas autore secināja, ka Bitcoin popularitāte gan lietotāju vidū, gan uzņēmumu vidū, kas sāk pieņemt Bitcoin digotālo valūtu, tikai t...

  4. Treatment of anti-Ma2/Ta paraneoplastic syndrome.

    Science.gov (United States)

    Kraker, Jessica

    2009-01-01

    The paraneoplastic syndrome caused by Ma2/Ta antibodies alone (not in conjunction with Ma1 or Ma3 antibodies) varies in presentation from classic limbic encephalitis. The Ma2 syndrome may present with symptoms referable to the brainstem, diencephalon, and limbic system. These clinical symptoms are accompanied by MRI changes and abnormal electroencephalographic findings. It is important to recognize when the encephalitic syndrome is secondary to Ma2 paraneoplastic antibodies, as the patients improve or stabilize most often when the underlying carcinoma is treated. Treatment of the paraneoplastic syndrome begins with recognition of the symptoms, such as memory impairment, seizures, sleep disturbances, bradykinesia or hypokinesia, and eye movement abnormalities. If a primary tumor is discovered during the workup, it should be removed and treated with the most up-to-date oncologic treatment available. In addition to oncologic treatment, the syndrome may be treated with an immunosuppressant regimen to optimize the neurologic outcome. Leaving the patient untreated will result in decline and eventual death from the cancer itself or from complications of the paraneoplastic syndrome.

  5. LAFD: TA-16 HE Facility Familiarization Tour, OJT 55258

    Energy Technology Data Exchange (ETDEWEB)

    Rutherford, Victor Stephen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-31

    Los Alamos National Laboratory (LANL) will conduct familiarization tours for personnel of the Los Alamos County Fire Department (LAFD) at TA-16 high explosives (HE) facilities. These familiarization tours are official LANL business; the purpose of these tours is to orient LAFD firefighters to the facility so that they can respond efficiently and quickly to a variety of emergency situations. This orientation includes, among other topics, ingress and egress of the area and buildings, layout and organization of the facility, evacuation procedures and assembly points, and areas of concern within the various buildings at the facility. LAFD firefighters have the skills and abilities to perform firefighting operations and other emergency response tasks that cannot be provided by LANL personnel who have the required clearance. This handout provides details of the information, along with maps and diagrams, to be presented during the familiarization tours. The handout will be distributed to the trainees at the time of the tour. A corresponding checklist will also be used as guidance during the familiarization tours to ensure that all required information is presented to LAFD personnel.

  6. A MISSÃO DO JESUÍTA HOJE

    Directory of Open Access Journals (Sweden)

    Jesus Hortal

    1977-01-01

    Full Text Available A Congregação Geral XXXII da Companhia de Jesus foi convocada expressamente para encontrar a resposta evangélica e inaciana às necessidades apostólicas do mundo de hoje. O artigo descreve os passos seguidos para a elaboração do Decreto 4, que leva por titulo "A Missão do Jesuita Hoje", assim como o seu conteúdo. Após um enquadramento inicial, dentro da teologia da missão, apresenta a diversidade de opiniões e as dificuldades para chegar a uma definição atualizada da missão do jesuíta. Apesar do ponto de vista particular, a problemática que surge desta exposição é universal: a compreensão da fé como elemento unificador de toda ação apostólica.

  7. TiTaCN-Co cermets prepared by mechanochemical technique: microstructure and mechanical properties

    OpenAIRE

    Fides, Martin; Hvizdoš, P.; Balko, Ján; Chicardi, E.; Gotor, F.J.

    2016-01-01

    Microstructure and mechanical characterization of (Ti,Ta)(C,N)-Co based solid solution cermets prepared by two mechanochemical synthesis processes (one- and two-step milling) and a pressureless sintering in protective helium atmosphere. Materials with composition of TixTa1- xC0.5N0.5-20%Co with two different Ti/Ta ratios (x = 0.9 and x = 0.95) were developed to prepare four groups of experimental materials. Microstructures were observed using confocal microscopy and grain size was ev...

  8. Superconductivity of Hg3NbF6 and Hg3TaF6

    International Nuclear Information System (INIS)

    Datars, W.R.; Morgan, K.R.; Gillespie, R.J.

    1983-01-01

    Low-temperature ac susceptibility measurements show that two new metallic compounds, Hg 3 TaF 6 and Hg 3 NbF 6 , are superconductors with a critical temperature of 7.0 K. Critical fields are 20% higher in Hg 3 TaF 6 but the temperature dependence of the critical field of the compounds is very similar down to 1.35 K. The critical field extrapolated to T = 0 K is 0.17 T for Hg 3 TaF 6 and 0.13 T for Hg 3 NbF 6

  9. Erosion behavior of W-Ta coatings in plasmas of stationary mirror penning discharges

    International Nuclear Information System (INIS)

    Belous, V.A.; Bondarenko, M.N.; Glazunov, G.P.; Ilchenko, A.V.; Kuprin, A.S.; Konotopskiy, A.L.; Lunyov, V.M.; Ovcharenko, V.D.

    2016-01-01

    Investigations had been carried out of the influence of Ta alloying (2...16 wt.%) in W-coatings on their erosion behavior in steady state plasmas of Penning discharges in different gases: argon, nitrogen, and hydrogen. The coatings were deposited on stainless steel substrates by argon ion sputtering of targets made from appropriate metals. For comparison the erosion behavior had been examined of pure W and Ta coatings obtained by the same method. It was shown the essential decrease of an erosion rate after Ta addition in W coatings. The possible physical mechanism is suggested to explain such erosion behavior

  10. Formation of titanium dioxide nanotubes on Ti–30Nb–xTa alloys by anodizing

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun-Sil [Department of Dental Materials and Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University, Gwangju (Korea, Republic of); Jeong, Yong-Hoon [Department of Dental Materials and Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University, Gwangju (Korea, Republic of); Biomechanics and Tissue Engineering Laboratory, Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH (United States); Choe, Han-Cheol, E-mail: hcchoe@chosun.ac.kr [Department of Dental Materials and Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University, Gwangju (Korea, Republic of); Brantley, William A. [Division of Restorative, Prosthetic and Primary Care Dentistry, College of Dentistry, The Ohio State University, Columbus, OH (United States)

    2013-12-31

    The goal of this study was to investigate the formation of titanium dioxide nanotubes on the surface of cast Ti–30Nb–xTa alloys by anodizing. The anodization technique for creating the nanotubes utilized a potentiostat and an electrolyte containing 1 M H{sub 3}PO{sub 4} with 0.8 wt.% NaF. The grain size of the Ti–30Nb–xTa alloys increased as the Ta content increased. Using X-ray diffraction, for the Ti–30Nb alloy the main peaks were identified as α″ martensite with strong peaks of β phase. The phases in the Ti–30Nb–xTa alloys changed from a duplex (α″ + β) microstructure to solely β phase with increasing Ta content. The nanotubes that formed on the surface of the Ti–30Nb–xTa alloys were amorphous TiO{sub 2} without an evidence of the crystalline anatase or rutile forms of TiO{sub 2}. Scanning electron microscopy revealed that the average diameters of the small and large nanotubes on the Ti–30Nb alloy not containing Ta were approximately 100 nm and 400 nm, respectively, whereas the small and large nanotubes on the alloy had diameters of approximately 85 nm and 300 nm, respectively. As the Ta content increased from 0 to 15 wt.%, the average lengths of the nanotubes increased from 2 μm to 3.5 μm. Energy-dispersive X-ray spectroscopy indicated that the nanotubes were principally composed of Ti, Nb, Ta, O and F. Contact angle measurements showed that the nanotube surface had good wettability by water droplets. - Highlights: • TiO{sub 2} nanotube layers on anodized Ti-30Nb-xTa alloys have been investigated. • Nanotube surface had an amorphous structure without heat treatment. • Nanotube diameter of Ti-30Nb-xTa decreased, whereas tube layer increased with Ta content. • The nanotube surface exhibited the low contact angle and good wettability.

  11. The hyperfine fields at 181Ta in HfFe2

    International Nuclear Information System (INIS)

    Cekic, B.; Ivanovic, N.; Manasijevic, M.; Koicki, S.; Koteski, V.; Cavor, J.; Radisavljevic, I.; Milosevic, Z.; Novakovic, N.

    2001-01-01

    The hyperfine fields (HFF) in the polycrystalline HfFe 2 binary compound consisting the two various phases MgCu 2 and MgZn 2 , were measured at 181 Ta probe ion sites by gamma-gamma time differential perturbed angular correlations (TDPAC) technique in a wide temperature range. The origin of the hyperfine magnetic field is discussed taking in account the coordination of the 181 Ta probe ion, its core polarization and the polarization of conduction electrons around the 181 Ta site in both phases. (author)

  12. Formation of titanium dioxide nanotubes on Ti–30Nb–xTa alloys by anodizing

    International Nuclear Information System (INIS)

    Kim, Eun-Sil; Jeong, Yong-Hoon; Choe, Han-Cheol; Brantley, William A.

    2013-01-01

    The goal of this study was to investigate the formation of titanium dioxide nanotubes on the surface of cast Ti–30Nb–xTa alloys by anodizing. The anodization technique for creating the nanotubes utilized a potentiostat and an electrolyte containing 1 M H 3 PO 4 with 0.8 wt.% NaF. The grain size of the Ti–30Nb–xTa alloys increased as the Ta content increased. Using X-ray diffraction, for the Ti–30Nb alloy the main peaks were identified as α″ martensite with strong peaks of β phase. The phases in the Ti–30Nb–xTa alloys changed from a duplex (α″ + β) microstructure to solely β phase with increasing Ta content. The nanotubes that formed on the surface of the Ti–30Nb–xTa alloys were amorphous TiO 2 without an evidence of the crystalline anatase or rutile forms of TiO 2 . Scanning electron microscopy revealed that the average diameters of the small and large nanotubes on the Ti–30Nb alloy not containing Ta were approximately 100 nm and 400 nm, respectively, whereas the small and large nanotubes on the alloy had diameters of approximately 85 nm and 300 nm, respectively. As the Ta content increased from 0 to 15 wt.%, the average lengths of the nanotubes increased from 2 μm to 3.5 μm. Energy-dispersive X-ray spectroscopy indicated that the nanotubes were principally composed of Ti, Nb, Ta, O and F. Contact angle measurements showed that the nanotube surface had good wettability by water droplets. - Highlights: • TiO 2 nanotube layers on anodized Ti-30Nb-xTa alloys have been investigated. • Nanotube surface had an amorphous structure without heat treatment. • Nanotube diameter of Ti-30Nb-xTa decreased, whereas tube layer increased with Ta content. • The nanotube surface exhibited the low contact angle and good wettability

  13. Molecular evolution of the rice blast resistance gene Pi-ta in invasive weedy rice in the USA.

    Directory of Open Access Journals (Sweden)

    Seonghee Lee

    Full Text Available The Pi-ta gene in rice has been effectively used to control rice blast disease caused by Magnaporthe oryzae worldwide. Despite a number of studies that reported the Pi-ta gene in domesticated rice and wild species, little is known about how the Pi-ta gene has evolved in US weedy rice, a major weed of rice. To investigate the genome organization of the Pi-ta gene in weedy rice and its relationship to gene flow between cultivated and weedy rice in the US, we analyzed nucleotide sequence variation at the Pi-ta gene and its surrounding 2 Mb region in 156 weedy, domesticated and wild rice relatives. We found that the region at and around the Pi-ta gene shows very low genetic diversity in US weedy rice. The patterns of molecular diversity in weeds are more similar to cultivated rice (indica and aus, which have never been cultivated in the US, rather than the wild rice species, Oryza rufipogon. In addition, the resistant Pi-ta allele (Pi-ta found in the majority of US weedy rice belongs to the weedy group strawhull awnless (SH, suggesting a single source of origin for Pi-ta. Weeds with Pi-ta were resistant to two M. oryzae races, IC17 and IB49, except for three accessions, suggesting that component(s required for the Pi-ta mediated resistance may be missing in these accessions. Signatures of flanking sequences of the Pi-ta gene and SSR markers on chromosome 12 suggest that the susceptible pi-ta allele (pi-ta, not Pi-ta, has been introgressed from cultivated to weedy rice by out-crossing.

  14. Molecular Evolution of the Rice Blast Resistance Gene Pi-ta in Invasive Weedy Rice in the USA

    Science.gov (United States)

    Lee, Seonghee; Jia, Yulin; Jia, Melissa; Gealy, David R.; Olsen, Kenneth M.; Caicedo, Ana L.

    2011-01-01

    The Pi-ta gene in rice has been effectively used to control rice blast disease caused by Magnaporthe oryzae worldwide. Despite a number of studies that reported the Pi-ta gene in domesticated rice and wild species, little is known about how the Pi-ta gene has evolved in US weedy rice, a major weed of rice. To investigate the genome organization of the Pi-ta gene in weedy rice and its relationship to gene flow between cultivated and weedy rice in the US, we analyzed nucleotide sequence variation at the Pi-ta gene and its surrounding 2 Mb region in 156 weedy, domesticated and wild rice relatives. We found that the region at and around the Pi-ta gene shows very low genetic diversity in US weedy rice. The patterns of molecular diversity in weeds are more similar to cultivated rice (indica and aus), which have never been cultivated in the US, rather than the wild rice species, Oryza rufipogon. In addition, the resistant Pi-ta allele (Pi-ta) found in the majority of US weedy rice belongs to the weedy group strawhull awnless (SH), suggesting a single source of origin for Pi-ta. Weeds with Pi-ta were resistant to two M. oryzae races, IC17 and IB49, except for three accessions, suggesting that component(s) required for the Pi-ta mediated resistance may be missing in these accessions. Signatures of flanking sequences of the Pi-ta gene and SSR markers on chromosome 12 suggest that the susceptible pi-ta allele (pi-ta), not Pi-ta, has been introgressed from cultivated to weedy rice by out-crossing. PMID:22043312

  15. Radionuclide contaminant analysis of small mammals at Area G, TA-54, Los Alamos National Laboratory, 1995

    International Nuclear Information System (INIS)

    Bennett, K.; Biggs, J.; Fresquez, P.

    1997-01-01

    At Los Alamos National Laboratory, small mammals were sampled at two waste burial sites (Site 1-recently disturbed and Site 2-partially disturbed) at Area G, Technical Area 54 and a control site on Frijoles Mesa (Site 4) in 1995. Our objectives were (1) to identify radionuclides that are present within surface and subsurface soils at waste burial sites, (2) to compare the amount of radionuclide uptake by small mammals at waste burial sites to a control site, and (3) to identify if the primary mode of contamination to small mammals is by surface contact or ingestion/inhalation. Three composite samples of at least rive animals per sample were collected at each site. Pelts and carcasses of each animal were separated and analyzed independently. Samples were analyzed for 241 Am, 90 Sr , 238 Pu, 239 Pu, total U, 137 Cs, and 3 H. Significantly higher (parametric West at p=0.05) levels of total U, 241 Am, 238 Pu and 239 Pu were detected in pelts than in carcasses of small mammals at TA-54. Concentrations of other measured radionuclides in carcasses were nearly equal to or exceeded the mean concentrations in the pelts. Our results show higher concentrations in pelts compared to carcasses, which is similar to what has been found at waste burial/contaminated sites outside of Los Alamos National Laboratory. Site 1 had a significantly higher (alpha=0.05, P=0.0125) mean tritium concentration in carcasses than Site 2 or Site 4. In addition Site 1 also had a significantly higher (alpha=0.05, p=0.0024) mean tritium concentration in pelts than Site 2 or Site 4. Site 2 had a significantly higher (alpha=0.05, P=0.0499) mean 239 Pu concentration in carcasses than either Site 1 or Site 4

  16. Construction of stable Ta{sub 3}N{sub 5}/g-C{sub 3}N{sub 4} metal/non-metal nitride hybrids with enhanced visible-light photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Yinhua, E-mail: yms418@126.com [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 2120013,PR China (China); Liu, Peipei; Chen, YeCheng; Zhou, Zhengzhong; Yang, Haijian [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 2120013,PR China (China); Hong, Yuanzhi; Li, Fan; Ni, Liang [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 2120013,PR China (China); Yan, Yongsheng [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 2120013,PR China (China); Gregory, Duncan H, E-mail: duncan.gregory@glasgow.ac.uk [School of Chemistry, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

    2017-01-01

    Highlights: • Novel Ta{sub 3}N{sub 5}/g-C{sub 3}N{sub 4} metal/non-metal nitride hybrids were synthesized. • The hybrid nitrides showed enhanced visible-light photocatalytic performance. • The Ta{sub 3}N{sub 5}/g-C{sub 3}N{sub 4} hybrid nitride exhibited excellent photostability. • The hole is the main photoactive specie for the degradation of RhB. - Abstract: In this paper, a novel Ta{sub 3}N{sub 5}/g-C{sub 3}N{sub 4} metal/non-metal nitride hybrid was successfully synthesized by a facile impregnation method. The photocatalytic activity of Ta{sub 3}N{sub 5}/g-C{sub 3}N{sub 4} hybrid nitrides was evaluated by the degradation of organic dye rhodamine B (RhB) under visible light irradiation, and the result indicated that all Ta{sub 3}N{sub 5}/g-C{sub 3}N{sub 4} samples exhibited distinctly enhanced photocatalytic activities for the degradation of RhB than pure g-C{sub 3}N{sub 4}. The optimal Ta{sub 3}N{sub 5}/g-C{sub 3}N{sub 4} composite sample, with Ta{sub 3}N{sub 5} mass ratio of 2%, demonstrated the highest photocatalytic activity, and its degradation rate constant was 2.71 times as high as that of pure g-C{sub 3}N{sub 4}. The enhanced photocatalytic activity of this Ta{sub 3}N{sub 5}/g-C{sub 3}N{sub 4} metal/metal-free nitride was predominantly attributed to the synergistic effect which increased visible-light absorption and facilitated the efficient separation of photoinduced electrons and holes. The Ta{sub 3}N{sub 5}/g-C{sub 3}N{sub 4} hybrid nitride exhibited excellent photostability and reusability. The possible mechanism for improved photocatalytic performance was proposed. Overall, this work may provide a facile way to synthesize the highly efficient metal/metal-free hybrid nitride photocatalysts with promising applications in environmental purification and energy conversion.

  17. Correlation between the transport mechanisms in conductive filaments inside Ta2O5-based resistive switching devices and in substoichiometric TaOx thin films

    Science.gov (United States)

    Rosário, Carlos M. M.; Thöner, Bo; Schönhals, Alexander; Menzel, Stephan; Wuttig, Matthias; Waser, Rainer; Sobolev, Nikolai A.; Wouters, Dirk J.

    2018-05-01

    Conductive filaments play a key role in redox-based resistive random access memory (ReRAM) devices based on the valence change mechanism, where the change of the resistance is ascribed to the modulation of the oxygen content in a local region of these conductive filaments. However, a deep understanding of the filaments' composition and structure is still a matter of debate. We approached the problem by comparing the electronic transport, at temperatures from 300 K down to 2 K, in the filaments and in TaOx films exhibiting a substoichiometric oxygen content. The filaments were created in Ta (15 nm)/Ta2O5 (5 nm)/Pt crossbar ReRAM structures. In the TaOx thin films with various oxygen contents, the in-plane transport was studied. There is a close similarity between the electrical properties of the conductive filaments in the ReRAM devices and of the TaOx films with x ˜ 1, evidencing also no dimensionality difference for the electrical transport. More specifically, for both systems there are two different conduction processes: one in the higher temperature range (from 50 K up to ˜300 K), where the conductivity follows a √{ T } dependence, and one at lower temperatures (<50 K), where the conductivity follows the exp(-1 / √{ T } ) dependence. This suggests a strong similarity between the material composition and structure of the filaments and those of the substoichiometric TaOx films. We also discuss the temperature dependence of the conductivity in the framework of possible transport mechanisms, mainly of those normally observed for granular metals.

  18. Influences of Pr and Ta doping concentration on the characteristic features of FTO thin film deposited by spray pyrolysis

    International Nuclear Information System (INIS)

    Turgut, Güven; Koçyiğit, Adem; Sönmez, Erdal

    2015-01-01

    The Pr and Ta separately doped FTO (10 at.% F incorporated SnO 2 ) films are fabricated via spray pyrolysis. The microstructural, topographic, optical, and electrical features of fluorine-doped TO (FTO) films are investigated as functions of Pr and Ta dopant concentrations. The x-ray diffraction (XRD) measurements reveal that all deposited films show polycrystalline tin oxide crystal property. FTO film has (200) preferential orientation, but this orientation changes to (211) direction with Pr and Ta doping ratio increasing. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) analyses show that all films have uniform and homogenous nanoparticle distributions. Furthermore, morphologies of the films depend on the ratio between Pr and Ta dopants. From ultraviolet-visible (UV-Vis) spectrophotometer measurements, it is shown that the transmittance value of FTO film decreases with Pr and Ta doping elements increasing. The band gap value of FTO film increases only at 1 at.% Ta doping level, it drops off with Pr and Ta doping ratio increasing at other doped FTO films. The electrical measurements indicate that the sheet resistance value of FTO film initially decreases with Pr and Ta doping ratio decreasing and then it increases with Pr and Ta doping ratio increasing. The highest value of figure of merit is obtained for 1 at.% Ta- and Pr-doped FTO film. These results suggest that Pr- and Ta-doped FTO films may be appealing candidates for TCO applications. (paper)

  19. Data of evolutionary structure change: 2A3TA-2PPDC [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 2A3TA-2PPDC 2A3T 2PPD A C --------LPRVKHTLVPPPFAHAHEQVAASGPVINEFE...EDTVKVMRTLTPTHVVFNGAVGALTGDKAMTAAVGEKVLIVHSQANRDTRPHLIGGHGDYVWATGKFNTPPDVDQETWFIP... GLN CA 428 2PPD C 2PPD...> 1 2PPD... C 2PPDC CAPPG-MVPWA

  20. Bixbyite-type phases in the system Ta-Zr-O-N

    Energy Technology Data Exchange (ETDEWEB)

    Luedtke, Tobias; Orthmann, Steven; Lerch, Martin [Technische Univ. Berlin (Germany). Inst. fuer Chemie

    2017-06-01

    Phase-pure tantalum/zirconium oxide nitrides and nitrides were synthesized by the ammonolysis of amorphous oxide precursors. The nitrogen-rich oxide nitrides with variable anion composition and the nitride TaZrN3 crystallize in the cubic bixbyite-type structure (space group Ia3). The nitrogen content of these compounds has a significant influence on the cell parameters, the atomic positions, and the optical band gap. The results extend the already well-studied Ta-Zr-O-N system by new oxide nitrides in addition to the already known baddeleyite- and anosovite-type phases. TaZrN{sub 3} can be considered as a thermodynamically stable ternary variant of metastable Ta{sub 2}N{sub 3}.

  1. Characteristics of (Ti,Ta)N thin films prepared by using pulsed high energy density plasma

    Energy Technology Data Exchange (ETDEWEB)

    Feng Wenran [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Chen Guangliang [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Li Li [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Lv Guohua [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Zhang Xianhui [College of Science, Changchun University of Science and Technology, Changchun 130022, Jilin Province (China); Niu Erwu [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Liu Chizi [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Yang Size [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China)

    2007-07-21

    (Ti,Ta)N films were prepared by pulsed high energy density plasma (PHEDP) from a coaxial gun in N{sub 2} gas. The coaxial gun is composed of a tantalum inner electrode and a titanium outer one. Material characteristics of the (Ti,Ta)N film were investigated by x-ray photoelectron spectroscopy and x-ray diffraction. The microstructure of the film was observed by a scanning electron microscope. The elemental composition and the interface of the film/substrate were analysed using Auger electron spectrometry. Our results suggest that the binary metal nitride film (Ti,Ta)N, can be prepared by PHEDP. It also shows that dense nanocrystalline (Ti,Ta)N film can be achieved.

  2. Czech Verse Processing System KVĚTA: Phonetic and Metrical Components

    Czech Academy of Sciences Publication Activity Database

    Plecháč, Petr

    2016-01-01

    Roč. 7, č. 2 (2016), s. 159-174 ISSN 1337-7892 Institutional support: RVO:68378068 Keywords : Verse Processing * KVĚTA * Czech language * phonetic and metrical annotation Subject RIV: AJ - Letters, Mass-media, Audiovision

  3. Mesoporous (Ta, Nb3W7 Modified with Stearic Acid Used as Solid Acids for Esterification

    Directory of Open Access Journals (Sweden)

    Fei Chang

    2017-01-01

    Full Text Available Mesoporous solid acids Ta3W7 and Nb3W7 were prepared from TaCl5 and NbCl5 with WCl6 in the presence of stearic acid (SA via a sol-gel method, respectively. For comparison, mesoporous Ta3W7-P123 mixed oxides and mesoporous Nb3W7-P123 mixed oxides were synthesized in the same way. The catalysts were characterized through TGA, XRD, SEM, TEM, BET, and NH3-TPD. Experimental results showed that Ta3W7-SA and Nb3W7-SA exhibited several advantages such as higher activity, shorter preparation period, lower cost, stronger acid sites, and higher surface area, which had potential to be used as mesoporous heterogeneous catalysts in biodiesel production.

  4. Stormwater Pollution Prevention Plan TA-60 Roads and Grounds Facility and Associated Sigma Mesa Staging Area

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval, Leonard Frank [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-01

    This Stormwater Pollution Prevention Plan (SWPPP) is applicable to operations at the Technical Area -60 (TA-60) Roads and Grounds Facility and Associated Sigma Mesa Staging Area off Eniwetok Drive, in Los Alamos County, New Mexico.

  5. Thickness-dependence of optical constants for Ta2O5 ultrathin films

    International Nuclear Information System (INIS)

    Zhang, Dong-Xu; Zheng, Yu-Xiang; Cai, Qing-Yuan; Lin, Wei; Wu, Kang-Ning; Mao, Peng-Hui; Zhang, Rong-Jun; Zhao, Hai-bin; Chen, Liang-Yao

    2012-01-01

    An effective method for determining the optical constants of Ta 2 O 5 thin films deposited on crystal silicon (c-Si) using spectroscopic ellipsometry (SE) measurement with a two-film model (ambient-oxide-interlayer-substrate) was presented. Ta 2 O 5 thin films with thickness range of 1-400 nm have been prepared by the electron beam evaporation (EBE) method. We find that the refractive indices of Ta 2 O 5 ultrathin films less than 40 nm drop with the decreasing thickness, while the other ones are close to those of bulk Ta 2 O 5 . This phenomenon was due to the existence of an interfacial oxide region and the surface roughness of the film, which was confirmed by the measurement of atomic force microscopy (AFM). Optical properties of ultrathin film varying with the thickness are useful for the design and manufacture of nano-scaled thin-film devices. (orig.)

  6. Hot Ta filament resistance in-situ monitoring under silane containing atmosphere

    International Nuclear Information System (INIS)

    Grunsky, D.; Schroeder, B.

    2008-01-01

    Monitoring of the electrical resistance of the Ta catalyst during the hot wire chemical vapor deposition (HWCVD) of thin silicon films gives information about filament condition. Using Ta filaments for silane decomposition not only the well known strong changes at the cold ends, but also changes of the central part of the filament were observed. Three different phenomena can be distinguished: silicide (stoichiometric Ta X Si Y alloys) growth on the filament surfaces, diffusion of Si into the Ta filament and thick silicon deposits (TSD) formation on the filament surface. The formation of different tantalum silicides on the surface as well as the in-diffusion of silicon increase the filament resistance, while the TSDs form additional electrical current channels and that result in a decrease of the filament resistance. Thus, the filament resistance behaviour during ageing is the result of the competition between these two processes

  7. Signature splitting in two quasiparticle rotational bands of 180, 182 Ta

    Indian Academy of Sciences (India)

    quasiparticle rotor model. The phase as well as magnitudeof the experimentally observed signature splitting in K π = 1 + band of 180 Ta, which could not be explained in earlier calculations, is successfully reproduced. The conflict regarding placement of ...

  8. Experimental and ab initio study of Ta-doped ZnO semiconductor

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, E. L., E-mail: munoz@fisica.unlp.edu.ar; Richard, D., E-mail: richard@fisica.unlp.edu.ar [UNLP, Departamento de Fisica and Instituto de Fisica La Plata (IFLP, CCT La Plata, CONICET), Fac. de Ciencias Exactas (Argentina); Eversheim, P. D. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen-und Kernphysik (H-ISKP) (Germany); Renteria, M., E-mail: renteria@fisica.unlp.edu.ar [UNLP, Departamento de Fisica and Instituto de Fisica La Plata (IFLP, CCT La Plata, CONICET), Fac. de Ciencias Exactas (Argentina)

    2010-04-15

    In this work, we present {gamma}-{gamma} Perturbed-Angular-Correlation results in polycrystalline ZnO semiconductor implanted with {sup 181}Hf({yields}{sup 181}Ta) probes. Calculations in Ta-doped ZnO were carried out using the Full-Potential Augmented Plane Wave plus local orbital method in a supercell and varying self-consistently the charge state of the impurity. Ta is a triple donor impurity with respect to Zn{sup 2 + } in ZnO and thus it can loose 1, 2 or 3 donor electrons under certain circumstances. As expected, the comparison between the experimental Electric-Field-Gradient tensor results and our ab initio predictions shows that the Ta impurity is in an ionized charge state at room temperature.

  9. Experimental and ab initio study of Ta-doped ZnO semiconductor

    International Nuclear Information System (INIS)

    Muñoz, E. L.; Richard, D.; Eversheim, P. D.; Rentería, M.

    2010-01-01

    In this work, we present γ–γ Perturbed-Angular-Correlation results in polycrystalline ZnO semiconductor implanted with 181 Hf(→ 181 Ta) probes. Calculations in Ta-doped ZnO were carried out using the Full-Potential Augmented Plane Wave plus local orbital method in a supercell and varying self-consistently the charge state of the impurity. Ta is a triple donor impurity with respect to Zn 2 +  in ZnO and thus it can loose 1, 2 or 3 donor electrons under certain circumstances. As expected, the comparison between the experimental Electric-Field-Gradient tensor results and our ab initio predictions shows that the Ta impurity is in an ionized charge state at room temperature.

  10. Thickness-dependence of optical constants for Ta2O5 ultrathin films

    Science.gov (United States)

    Zhang, Dong-Xu; Zheng, Yu-Xiang; Cai, Qing-Yuan; Lin, Wei; Wu, Kang-Ning; Mao, Peng-Hui; Zhang, Rong-Jun; Zhao, Hai-bin; Chen, Liang-Yao

    2012-09-01

    An effective method for determining the optical constants of Ta2O5 thin films deposited on crystal silicon (c-Si) using spectroscopic ellipsometry (SE) measurement with a two-film model (ambient-oxide-interlayer-substrate) was presented. Ta2O5 thin films with thickness range of 1-400 nm have been prepared by the electron beam evaporation (EBE) method. We find that the refractive indices of Ta2O5 ultrathin films less than 40 nm drop with the decreasing thickness, while the other ones are close to those of bulk Ta2O5. This phenomenon was due to the existence of an interfacial oxide region and the surface roughness of the film, which was confirmed by the measurement of atomic force microscopy (AFM). Optical properties of ultrathin film varying with the thickness are useful for the design and manufacture of nano-scaled thin-film devices.

  11. Stormwater Pollution Prevention Plan TA-60 Asphalt Batch Plant Revision 2: January 2017

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval, Leonard Frank [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-01

    The Stormwater Pollution Prevention Team (PPT) is applicable to operations at the Technical Area (TA)- 60 Asphalt Batch Plant (ABP) located on Eniwetok Drive/Sigma Mesa, in Los Alamos County, New Mexico at Los Alamos National Laboratory (LANL).

  12. CRED REA Fish Team Stationary Point Count Surveys at Ta'u, American Samoa, 2006

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Stationary Point Counts at 4 stations at each survey site were surveyed as part of Rapid Ecological Assessments (REA) conducted at 9 sites around Ta'u in the...

  13. Ta1, a novel 105 KD human T cell activation antigen defined by a monoclonal antibody.

    Science.gov (United States)

    Fox, D A; Hussey, R E; Fitzgerald, K A; Acuto, O; Poole, C; Palley, L; Daley, J F; Schlossman, S F; Reinherz, E L

    1984-09-01

    By using a murine monoclonal antibody produced against an IL 2-dependent human T cell line, we defined a T lineage-specific molecule, termed Ta1, that is expressed strongly on activated T lymphocytes of both the T4 and T8 subsets, as well as on T cell lines and clones, but only weakly on a fraction of resting T cells. SDS-PAGE analysis of immunoprecipitates from 125I-labeled, activated T cells demonstrates a single major band of apparent m.w. 105 KD under both reducing and nonreducing conditions. Unlike anti-IL 2 receptor antibodies, anti-Ta1 does not inhibit T cell proliferative responses to mitogen, antigen, or IL 2-containing medium. Moreover, anti-Ta1 has no effect on T cell-mediated cytotoxicity. Ta1 appears to be a novel human T cell-specific activation antigen that may serve as a useful marker of T cell activation in human disease.

  14. CRED REA Coral Health and Disease Assessment at Ta'u Island, American Samoa in 2008

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Coral health and disease assessments were conducted along 2 consecutively placed 25-m transects, as part of Rapid Ecological Assessments conducted at 9 sites at Ta'u...

  15. A Linear Accelerator for TA-FD calibration

    Science.gov (United States)

    Shibata, T.; Ikeda, D.; Ikeda, M.; Enomoto, A.; Ohsawa, S.; Kakiha, K.; Kakihara, K.; Sagawa, H.; Satoh, M.; Shidara, T.; Sugimura, T.; Fukushima, M.; Fukuda, S.; Furukawa, K.; Yoshida, M.

    The energy of the primary cosmic ray can be calculated from fluorescence photons detected by fluorescence telescope. However, since we can not know the true energy of primary cosmic ray, it is difficult to calibrate between number of photons and energy directly. In TA project, we will create pseudo- cosmic ray events by using accelerated electron beam which is injected in the air. The injected electron beam creates an air shower and fluorescence photons are emitted. We can calibate between electron beam energy which is known exactry and detected photons. We are developping a small linear accelerator (Linac) at High Energy Accelerator Research Organization (KEK) in Japan. The maximum energy is 40MeV, the typical current is 0.16nC, and the intensity per pulse is 6.4mJ. The accuracy of beam energy is less than 1%. The Linac consists of a -100kV pulse type electron gun, a 1.5m pre-buncher and buncher tube, a 2m S-band accelerator tube, a quadrupole magnet, a 90 degree bending magnet, and a S-Band(2856MHz) 50MW high power klystron as RF source. We chekced the performance of the electron beam, energy resolution, beam spread, beam current, and beam loss by PARMELA simulation, and checked the air shower by electron beam and number of the detected photons by detector simulation which are made by GEANT4. In this Spring, we will do the full beam test in KEK. The beam operation in Utah will be started from this Autumn. In this talk, we will report about the results of the beam test and calibration method by this Linac.

  16. Atomic layer deposition and properties of mixed Ta2O5 and ZrO2 films

    Directory of Open Access Journals (Sweden)

    Kaupo Kukli

    2017-02-01

    Full Text Available Thin solid films consisting of ZrO2 and Ta2O5 were grown by atomic layer deposition at 300 °C. Ta2O5 films doped with ZrO2, TaZr2.75O8 ternary phase, or ZrO2 doped with Ta2O5 were grown to thickness and composition depending on the number and ratio of alternating ZrO2 and Ta2O5 deposition cycles. All the films grown exhibited resistive switching characteristics between TiN and Pt electrodes, expressed by repetitive current-voltage loops. The most reliable windows between high and low resistive states were observed in Ta2O5 films mixed with relatively low amounts of ZrO2, providing Zr to Ta cation ratio of 0.2.

  17. Broadband strip-line ferromagnetic resonance spectroscopy of soft magnetic CoFeTaZr patterned thin films

    Science.gov (United States)

    Gupta, S.; Kumar, D.; Jin, T. L.; Nongjai, R.; Asokan, K.; Ghosh, A.; Aparnadevi, M.; Suri, P.; Piramanayagam, S. N.

    2018-05-01

    In this paper, magnetic and magnetization dynamic properties of compositionally patterned Co46Fe40Ta9Zr5 thin films are investigated. A combination of self-assembly and ion-implantation was employed to locally alter the composition of Co46Fe40Ta9Zr5 thin film in a periodic manner. 20 keV O+ and 60 keV N+ ions were implanted at different doses in order to modify the magnetization dynamic properties of the samples in a controlled fashion. Magnetic hysteresis loop measurements revealed significant changes in the coercivity for higher influences of 5 × 1016 ions per cm2. In particular, N+ implantation was observed to induce two phase formation with high and low coercivities. Broadband strip-line ferromagnetic resonance spectroscopy over wide range of frequency (8 - 20 GHz) was used to study the magnetization dynamics as a function of ion-beam dosage. With higher fluences, damping constant showed a continuous increase from 0.0103 to 0.0430. Such control of magnetic properties at nano-scale using this method is believed to be useful for spintronics and microwave device applications.

  18. Textured and tungsten-bronze-niobate-doped (K,Na,Li)(Nb,Ta)O3 piezoceramic materials

    International Nuclear Information System (INIS)

    Soller, Thomas; Bathelt, Robert; Benkert, Katrin; Bodinger, Hermann; Schuh, Carsten; Schlenkrich, Falko

    2010-01-01

    In this study, the effects of an alkaline-earth niobate doping in tungsten-bronze (TB) stoichiometry on the piezoelectric properties and the phase transition temperatures of lead-free (K,Na,Li)(Nb,Ta)O 3 ceramics were investigated. In particular, the TB compounds barium niobate (BN), barium sodium niobate (BNN) and strontium calcium sodium niobate (SCNN) were investigated. The TB-modified ceramics show promising piezoelectric properties with large-signal piezo coefficients, d 33 * lose to 400 pm/V, planar coupling coefficients, k p , up to 0.45 and Curie temperatures of approximately 310 .deg. C. In addition, the effect of texturing on the undoped (K,Na,Li)(Nb,Ta)O 3 base composition via templated grain growth (TGG) with microcrystalline NaNbO 3 templates was examined. Lotgering factors up to 81% and strain enhancements by a factor 1.5 with large-signal values of d 33 * up to 550 pm/V could be achieved in the textured samples.

  19. Radiological survey and decontamination of the former main technical area (TA-1) at Los Alamos, New Mexico

    International Nuclear Information System (INIS)

    Ahlquist, A.J.; Stoker, A.K.; Trocki, L.K.

    1977-12-01

    A radiological survey was conducted on the undeveloped portions of the site of the former Main Technical Area (TA-1) of the Los Alamos Scientific Laboratory in north-central New Mexico. Between 1943 and 1965, research work on nuclear weapons was carried out in TA-1. The area was decontaminated and demolished in stages, and beginning in 1966 the land was given to Los Alamos County or sold to private interests. The survey disclosed traces of radioactive contamination undetected or considered insignificant during original demolition in the 1950s and 1960s. The remaining contamination was removed in 1975 and 1976 to levels considered to pose no health or safety hazards and, further, to the lowest levels considered practicable. Methods used in the survey included measurement techniques for detecting alpha emitters such as uranium and plutonium, extensive surface and subsurface soil sampling, and use of conventional health physics instrumentation to provide detailed information on approximately 16 hectares (40 acres) of land. As a result of the decontamination efforts, approximately 15,000 m 3 of contaminated or potentially contaminated material was removed to an approved radioactive waste disposal site on ERDA property. Full details of the methods, findings, decision criteria, and as-left conditions are documented

  20. Interferon-γ gene polymorphisms at +874T/A loci associated with response to treatment with hepatitis C virus

    Directory of Open Access Journals (Sweden)

    Hosein Norozian

    2016-02-01

    Full Text Available Background: Hepatitis C virus (HCV is a worldwide health problem, which associated with cirrhosis and hepatocellular carcinoma. Interferon-α and Ribavirin are only acceptable treatment regimen for these patients. These regimen are effective only on 50% of the patients. The aim of this study was to evaluate the response to treatment with interferon gamma gene polymorphism in patients with hepatitis C. Materials and Methods: In this study, a cross - sectional study, response or lack of response to treatment in 78 patients treated with interferon gamma gene polymorphism were studied at Shiraz Namazi Hospital from 2011-2012 . DNA samples extract by salt (salting out and interferon gamma gene polymorphism (+874T/A IFN–gamma was evaluate with ARMS-PCR technique. Data were analyzed using EPI Info2000 and SPSS 16 software (chi-square test. Results: Results showed that 39 patients (50% out of 78 studied patients had TT alleles, 11 patients (1.14% had AA alleles and 28 patients (9.39% had TA alleles. 49 patients (62.82% responded to treatment. TT genotype and allele frequencies between the studied groups showed significant differencey (P=0.002. Conclusion: Interferon gamma is a key cytokine in the immune response against hepatitis C. Polymorphism in the interferon-gamma gene is (+874T/AIFN–gamma One of the most important factors interferes with treatment response in hepatitis C patients.

  1. Perturbed angular correlation study of 181Ta-doped PbTi1-xHfxO3 compounds

    International Nuclear Information System (INIS)

    Alonso, R.E.; López García, A.R.; Rubia, M.A. de la; De Frutos, J.

    2012-01-01

    In this work, the hyperfine quadrupole interaction at Ta-doped PbTi 1-x Hf x O 3 polycrystalline samples is studied for the first time. Powders with x=0.25, 0.50 and 0.75 were prepared and characterized by X-ray diffraction analysis. Perturbed Angular Correlation (PAC) analyses were done as a function of temperature, using low concentration 181 Ta nuclei as probes. In the ferroelectric and paraelectric phases of these compounds two sites were occupied by the probes. For each site the quadrupole frequency, asymmetry and relative distribution width parameters were obtained as a function of temperature above and below the Curie temperature (T C ). One of these sites was assigned to the regular Ti-Hf site, while the other one was assigned to some kind of defect. The behavior of the hyperfine parameters as a function of temperature was analyzed in terms of a recent published phase diagram and the presence of disorder below and above T C . For the three compositions measured, the obtained hyperfine parameters present discontinuities which correspond to the ferroelectric-paraelectric phase transition. In both phases it was found broad frequency distributed interactions. The disorder in the electronic distribution would be responsible for the broad line width of the hyperfine interaction.

  2. Extraordinary high strength Ti-Zr-Ta alloys through nanoscaled, dual-cubic spinodal reinforcement.

    Science.gov (United States)

    Biesiekierski, Arne; Ping, Dehai; Li, Yuncang; Lin, Jixing; Munir, Khurram S; Yamabe-Mitarai, Yoko; Wen, Cuie

    2017-04-15

    While titanium alloys represent the current state-of-the-art for orthopedic biomaterials, concerns still remain over their modulus. Circumventing this via increased porosity requires high elastic admissible strains, yet also limits traditional thermomechanical strengthening techniques. To this end, a novel β-type Ti-Zr-Ta alloy system, comprised of Ti-45Zr-10Ta, Ti-40Zr-14Ta, Ti-35Zr-18Ta and Ti-30Zr-22Ta, was designed and characterized mechanically and microstructurally. As-cast, this system displayed extremely high yield strengths and elastic admissible strains, up to 1.4GPa and potentially 1.48%, respectively. This strength was attributed to a nanoscaled, cuboidal structure of semi-coherent, dual body-centered cubic (BCC) phases, arising from the thermodynamics of interaction between Ta and Zr; this morphology occurring with dual BCC-phases is heretofore unreported in Ti-based alloys. Further, cell proliferation investigated by MTS assay suggests this was achieved without sacrificing biocompatibility, with no significant difference to either empty-well or commercially-pure Ti controls noted. The current research details microstructural, mechanical, and biological investigations into four novel biomedical alloys in a hitherto uninvestigated region of the Ti-Zr-Ta alloy system; Ti-45Zr-10Ta, Ti-40Zr-14Ta, Ti-35Zr-18Ta and Ti-30Zr-22Ta. We find that the investigated alloys display 0.2% yield strengths of up to 1.40GPa and elastic admissible strains of up to 1.48%, along with biological properties comparable to that seen in the conventional metallic biomaterial ASTM Grade-2 CP-Ti, achieved in the complete absence of traditional thermomechanical processing techniques. This is attributed to the presence of a dual-BCC cuboidal nanostructure, achieved via spinodal decomposition; while similar structures have been reported in e.g. Ni-based superalloys, we believe this is the first such structure investigated in a Ti-based material. As such, this work is felt to be of

  3. Bioactivity analysis of the Ta (V doped SiO2–CaO–Na2O–P2O5 ceramics prepared by solid state sintering method

    Directory of Open Access Journals (Sweden)

    Rehana Zia

    2016-02-01

    Full Text Available The main objective of the study was to control the degradation rate of material at a higher degradation rate improving the chemical stability of the material. Ta is known to have good chemical resistance, biocompatibility and show no adverse biological response. In the present study, SiO2–Na2O–CaO–P2O5 bioceramics with different Ta2O5 contents was prepared by solid state sintering method at 1000 °C. The as-sintered ceramics were subjected to immersion studies in stimulated body fluid (SBF for 21 days under static condition and characterized by XRD, FTIR, SEM, and AAS. The findings of the research indicate that the addition of Ta2O5 controlled degradability, and all samples showed sufficient bioactivity.

  4. Study on mechanical properties and metallograph of high density function alloy Ta-12W

    International Nuclear Information System (INIS)

    Liu Taiping; Huang Zhenchi

    1998-12-01

    As a new material, the study on the metallograph and properties of Ta-12W alloy has been set about to testify its employ characteristics. The alloy's metallograph specimen preparation methods to illustrate microstructure are found out, 12 dose of chemical-corrosives are given. The author studies the metallograph, weld structure and properties, and chemical-corrosive resistance, provides scientific base for future research on Ta-12 W alloy

  5. New TA Index-Based Rollover Prevention System for Electric Vehicles

    OpenAIRE

    Xiang Liu; Min Xu; Mian Li

    2015-01-01

    In addition to clean transportation and energy savings, electric vehicles can inherently offer better performance in the field of active safety and dynamic stability control, thanks to the superior fast and accurate control characteristics of electric motors. With the novel wheel status parameter TA for electric vehicles proposed by the authors in an earlier publication, a new TA index (TAI)-based rollover prevention method is presented in this paper to improve the driving performance of EV...

  6. Contribution have the survey of the transformation {sup 181}Hf {yields} {sup 181}Ta (17 {mu}s) {yields} {sup 181}Ta; Contribution a l'etude de la transformation {sup 181}Hf {yields} {sup 181}Ta (17 {mu}s) {yields} {sup 181}Ta

    Energy Technology Data Exchange (ETDEWEB)

    Baullini, R; Chaminade, R; Desneiges, P; Grjebine, T; Quidort, J; Wahl, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1953-07-01

    The metastable state of Ta, whose period is around 20 microseconds, has been discovered by De BENEDETTI and Mc GOWAM who done measurements of deferred coincidences between the particles beta and the electrons of conversion given out by the hafnium radiated by thermal neutrons. We measured the period of {sup 181}Ta{sup *} by measures of deferred coincidences {beta}-e{sup -} and {beta}-{gamma}. A method of survey of the specter of photons amplitudes emitted by {sup 181}Ta{sup *} has been fit. This method permitted to solve the presence of {gamma} in the radiation emitted in synchronism with the deexcitation of {sup 181}Ta{sup *}. Finally in a last chapter, we propose a method of dosage of the {sup 181}Hf in presence of other radioelements. (M.B.) [French] L'etat metastable de Ta, dont la periode est voisine de 20 microsecondes, a ete decouvert par DE BENEDETTI et Mc GOWAM qui effectuaient des mesures de coincidences differees entre les particules beta et les electrons de conversion emis par du hafnium irradie par des neutrons thermiques. Nous avons mesure la periode de {sup 181}Ta{sup *} par des mesures de coincidences differees {beta}-e{sup -} et {beta}-{gamma}. Une methode d'etude du spectre d'amplitudes des photons emis par {sup 181}Ta{sup *} a ete mise au point. Cette methode a permis d'eclaircir la presence de {gamma} dans le rayonnement emis en synchronisme avec la desexcitation de {sup 181}Ta{sup *}. Enfin dans un dernier chapitre, on proposera une methode de dosage du {sup 181}Hf en presence d'autres radioelements. (M.B.)

  7. Signature inversion of the semi-decoupled band in the odd-odd nucleus 170Ta

    International Nuclear Information System (INIS)

    Deng Fuguo; Yang Chunxiang; Zhou Hongyu; Sun Huibin; Lu Jingbin; Zhao Guangyi; Yin Lichang; Liu Yunzuo

    2001-01-01

    The high-spin states of the odd-odd nucleus 170 Ta have been studied by the 155 Gd( 19 F, 4n) 170 Ta reaction at the beam energy of 97 MeV. The α = 1 sequence of the semi-decoupled band has been pushed to higher-spin states and the signature inversion point was observed at 19.5 ℎ. the results are compared with those of the neighbouring odd-odd nuclei

  8. Extraction behavior of Nb and Ta in HF solutions with tributyl phosphate

    International Nuclear Information System (INIS)

    Murakami, M.; Tsuto, S.; Ooe, K.; Goto, S.; Kudo, H.; Haba, H.; Kanaya, J.

    2013-01-01

    Extraction behavior of carrier-free Nb and Ta with tributyl phosphate (TBP) from HF solutions was studied by a batch method. Tantalum is extracted well to an organic phase, while Nb is left in an aqueous phase at 0.053-1.0 M HF concentrations. The similar extraction trends of Nb and Ta are shown in the solid phase extraction using a TBP resin. The extraction equilibria in the solid phase extraction are attained within ∼10 s. (author)

  9. Synthesis and characterization of Zn3Ta2O8 nanomaterials by hydrothermal method

    International Nuclear Information System (INIS)

    Bîrdeanu, M.; Bîrdeanu, A.-V.; Gruia, A.S.; Fagadar-Cosma, E.; Avram, C.N.

    2013-01-01

    Graphical abstract: The results of an experimental program that was focused on obtaining the Zn 3 Ta 2 O 8 nanocrystalline synthesized by hydrothermal method using tantalum (V) oxide and zinc nitrate, the results of the nanomaterial’s structure characterization and the optical spectral properties of such nanomaterials that were thoroughly investigated. Also, the experimental results are compared with ab initio calculations of electronic properties of Zn 3 Ta 2 O 8 . Highlights: •Zn 3 Ta 2 O 8 nanomaterials were synthesized by hydrothermal method and characterized. •The obtained nanomaterials has excellent phosphor, optical and morphological properties. •The material can be used in designing high performance optoelectronical devices. -- Abstract: Zn 3 Ta 2 O 8 has been synthesized by hydrothermal method using tantalum (V) oxide and zinc nitrate. The crystal structure and microstructure, phase composition and the absorption of Zn 3 Ta 2 O 8 nanomaterials were characterized by X-ray diffraction, FT/IR measurements, UV–VIS measurements, PL measurements, SEM and AFM techniques and BET analysis. XRD results show the single phase of Zn 3 Ta 2 O 8 and the average particle size that is 52 nm. This narrow nanometer size was also confirmed by AFM measurements. BET analysis revealed that the nanomaterials are mesoporous. The PL spectra show the blue luminescence of Ta 2 Zn 3 O 8 . Besides, in the present work we report ab initio calculations regarding electronic properties of Zn 3 Ta 2 O 8 ; the theoretical results are compared with the experimental ones

  10. Perpendicular magnetic anisotropy of CoFeB\\Ta bilayers on ALD HfO2

    Directory of Open Access Journals (Sweden)

    Bart F. Vermeulen

    2017-05-01

    Full Text Available Perpendicular magnetic anisotropy (PMA is an essential condition for CoFe thin films used in magnetic random access memories. Until recently, interfacial PMA was mainly known to occur in materials stacks with MgO\\CoFe(B interfaces or using an adjacent crystalline heavy metal film. Here, PMA is reported in a CoFeB\\Ta bilayer deposited on amorphous high-κ dielectric (relative permittivity κ=20 HfO2, grown by atomic layer deposition (ALD. PMA with interfacial anisotropy energy Ki up to 0.49 mJ/m2 appears after annealing the stacks between 200°C and 350°C, as shown with vibrating sample magnetometry. Transmission electron microscopy shows that the decrease of PMA starting from 350°C coincides with the onset of interdiffusion in the materials. High-κ dielectrics are potential enablers for giant voltage control of magnetic anisotropy (VCMA. The absence of VCMA in these experiments is ascribed to a 0.6 nm thick magnetic dead layer between HfO2 and CoFeB. The results show PMA can be easily obtained on ALD high-κ dielectrics.

  11. A theoretical inquiry into the question of W and Ta (100) atomic structures

    International Nuclear Information System (INIS)

    Treglia, G.; Spanjaard, D.

    1983-01-01

    In spite of the very large number of experiments (LEED, AES, UPS, MeV He + scattering, work function, FIM) carried out on W (100), no structural model consistent with all the data has been proposed yet: in particular, the question of the reconstruction thermally induced when the sample is cooled below room temperature remains a puzzling problem. Furthermore, from a theoretical point of view, no definitive answer has been given. Actually, either the mechanism invoked for the reconstruction is too weak, or some contributions are omitted or calculated without sufficient care. The surface energy of W (100) is computed taking into account the band term treated in the tight binding approximation, a pairwise repulsive potential of the Born-Mayer type and the electronic correlation contribution obtained from a perturbation treatment of the Hubbard model in the band limit. This energy is then fully minimised with respect to all coordinates of surface atoms, keeping all atoms neutral for any displace,ment. It is found that the unreconstructed surface is the most stable at T = 0 K and discuss this unexpected result. A similar calculation for Ta (100) leads to opposite conclusions. (author)

  12. X-ray microtomography study of the spallation response in Ta-W

    International Nuclear Information System (INIS)

    McDonald, S A; Withers, P J; Cotton, M; Millett, J C F; Bourne, N K

    2014-01-01

    Measurement of the damage field resulting from spallation due to shock induced loading is an important aspect of understanding the mechanisms controlling the dynamic tensile failure process. Furthermore, the ability to observe in three-dimensions, and in a non-invasive manner, the physical damage present in a spalled sample post-impact can provide important data for predictive damage models. In the current study, the influence of peak shock stress and pulse duration on the spallation damage response in the tantalum alloy Ta-2.5% W is presented. Rear surface velocimetry (HetV) measurements from plate impact experiments have been combined with 3-D characterisation and quantification of the resulting damage evolution in the recovered targets using X-ray microtomography. Small differences in spall strength are observed - an increase in the pulse duration results in a decrease in spall strength, while spall strength increases with increase in peak shock stress. The level of damaged induced (void coalescence) is more significant for an increase in pulse duration, with a local damage volume fraction double that of the case for an increase in peak shock stress.

  13. The Wheat Bax Inhibitor-1 Protein Interacts with an Aquaporin TaPIP1 and Enhances Disease Resistance in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Pan-Pan Lu

    2018-01-01

    Full Text Available Bax inhibitor-1 (BI-1 is an endoplasmic reticulum (ER-resident cell death suppressor evolutionarily conserved in eukaryotes. The ability of BI-1 to inhibit the biotic and abiotic stresses have been well-studied in Arabidopsis, while the functions of wheat BI-1 are largely unknown. In this study, the wheat BI-1 gene TaBI-1.1 was isolated by an RNA-seq analysis of Fusarium graminearum (Fg-treated wheat. TaBI-1.1 expression was induced by a salicylic acid (SA treatment and down-regulated by an abscisic acid (ABA treatment. Based on β-glucuronidase (GUS staining, TaBI-1.1 was expressed in mature leaves and roots but not in the hypocotyl or young leaves. Constitutive expression of TaBI-1.1 in Arabidopsis enhanced its resistance to Pseudomonas syringae pv. Tomato (Pst DC3000 infection and induced SA-related gene expression. Additionally, TaBI-1.1 transgenic Arabidopsis exhibited an alleviation of damage caused by high concentrations of SA and decreased the sensitivity to ABA. Consistent with the phenotype, the RNA-seq analysis of 35S::TaBI-1.1 and Col-0 plants showed that TaBI-1.1 was involved in biotic stresses. These results suggested that TaBI-1.1 positively regulates SA signals and plays important roles in the response to biotic stresses. In addition, TaBI-1.1 interacted with the aquaporin TaPIP1, and both them were localized to ER membrane. Furthermore, we demonstrated that TaPIP1 was up-regulated by SA treatment and TaPIP1 transgenic Arabidopsis enhanced the resistance to Pst DC3000 infection. Thus, the interaction between TaBI-1.1 and TaPIP1 on the ER membrane probably occurs in response to SA signals and defense response.

  14. Osmanlı Dönemi Başlıklı Ortakent Mezar Taşları Ottoman Period Headed Gravestones of Ortakent

    Directory of Open Access Journals (Sweden)

    H.Kamil BİÇİCİ

    2012-12-01

    Full Text Available This concerns, “Ortakent Gravestones.”. Among the cemetery of Ortakent, The dates of the gravestones are between 18.th-20.th centuries and 20 samples of 30 are from 18.th. century, 9 are from 19.th., 1 is from 20.th. century. Gravestones were of marble. The lenghts of the stones are between 140 cm.-45 cm., their widths are between 36 cm.-14 cm., their thicknesses are between 14 cm.-3.5 cm. Most of the samples are in rectangular and shapes and some are rectangular-prizmal. 3 of them have Foot gravestones. 30 head gravestones have large wadded turban (kavuk, turban (sarık, fez (fes and kerchief. All of the gravestones have inscriptions. 5 of them are without inscriptions. Inscriptions on 3 samples were laid diagonal, and 27 of them were laid in a linear system, 30 of head ve foot gravesones are in good condition. 3 samples are broken. 19 of 30 gravestones are men’s and 11 are of women’s. While scarping was used for making gravestones are scarping, and painting were used as the maindecoration tecnique is seen on foot stone with the painting technique,inscriptions of stones were coloured. Most of the inscriptions anddecorations are relieved. Decoration subjects seen on gravestones arephytomorphic, geometric, objective and calligraphic. “Osmanlı Dönemi Başlıklı Ortakent Mezar Taşları” konulu bu incelemede Ortakent Mezarlığında bulunan 30 mezar taşı araştırılarak, çalışmamızda yer almıştır. Mezar taşlarında tarihi bilinen bütün örnekler XVII. yy. ikinci çeyreği ile XX. yy. ilk çeyreği arasındadır. 30 örnekten 20 tanesi XVIII. yy., 9 tanesi XIX. yy., 1 tanesi XX. yy.dır. Mezar taşlarının hepsi mermer malzemeden yapılmıştır. Mezar taşlarının büyükten küçüğe doğru boyları 140 cm. ile 45 cm., genişlikleri 36 cm. ile 14 cm., kalınlıkları ise 14 ile 3.5 cm. arasında değişmektedir. Ortakent’te bulunan mezar taşları şahideli tiptedir. Örneklerin çoğu dikdörtgen gövdelidir. 3

  15. Transuranic waste characterization sampling and analysis plan

    International Nuclear Information System (INIS)

    1994-01-01

    Los Alamos National Laboratory (the Laboratory) is located approximately 25 miles northwest of Santa Fe, New Mexico, situated on the Pajarito Plateau. Technical Area 54 (TA-54), one of the Laboratory's many technical areas, is a radioactive and hazardous waste management and disposal area located within the Laboratory's boundaries. The purpose of this transuranic waste characterization, sampling, and analysis plan (CSAP) is to provide a methodology for identifying, characterizing, and sampling approximately 25,000 containers of transuranic waste stored at Pads 1, 2, and 4, Dome 48, and the Fiberglass Reinforced Plywood Box Dome at TA-54, Area G, of the Laboratory. Transuranic waste currently stored at Area G was generated primarily from research and development activities, processing and recovery operations, and decontamination and decommissioning projects. This document was created to facilitate compliance with several regulatory requirements and program drivers that are relevant to waste management at the Laboratory, including concerns of the New Mexico Environment Department

  16. TaGW2, a Good Reflection of Wheat Polyploidization and Evolution.

    Science.gov (United States)

    Qin, Lin; Zhao, Junjie; Li, Tian; Hou, Jian; Zhang, Xueyong; Hao, Chenyang

    2017-01-01

    Hexaploid wheat consists of three subgenomes, namely, A, B, and D. These well-characterized ancestral genomes also exist at the diploid and tetraploid levels, thereby rendering wheat as a good model species for studying polyploidization. Here, we performed intra- and inter-species comparative analyses of wheat and its relatives to dissect polymorphism and differentiation of the TaGW2 genes. Our results showed that genetic diversity of TaGW2 decreased with progression from the diploids to tetraploids and hexaploids. The strongest selection occurred in the promoter regions of TaGW2-6A and TaGW2-6B . Phylogenetic trees clearly indicated that Triticum urartu and Ae. speltoides were the donors of the A and B genomes in tetraploid and hexaploid wheats. Haplotypes detected among hexaploid genotypes traced back to the tetraploid level. Fst and π values revealed that the strongest selection on TaGW2 occurred at the tetraploid level rather than in hexaploid wheat. This infers that grain size enlargement, especially increased kernel width, mainly occurred in tetraploid genotypes. In addition, relative expression levels of TaGW2s significantly declined from the diploid level to tetraploids and hexaploids, further indicating that these genes negatively regulate kernel size. Our results also revealed that the polyploidization events possibly caused much stronger differentiation than domestication and breeding.

  17. High temperature oxidation resistance of (Ti,Ta)(C,N)-based cermets

    International Nuclear Information System (INIS)

    Chicardi, E.; Córdoba, J.M.; Gotor, F.J.

    2016-01-01

    Highlights: • Cermets based on (Ti,Ta)(C,N) were oxidized in air between 800 and 1100 °C for 48 h. • The substitution of Ti by Ta resulted in a high resistance to oxidation. • A protective layer of cobalt titanates at the surface of cermets was observed. • A rutile phase in which some Ti"4"+ are replaced by Ta"5"+ was detected. • This replacement decelerated the oxygen diffusion into the cermets. - Abstract: Cermets based on titanium–tantalum carbonitride were oxidized in static air between 800 °C and 1100 °C for 48 h. The thermogravimetric and microstructural study showed an outstanding reduction in the oxidation of more than 90% when the Ta content was increased. In cermets with low Ta content, the formation of a thin CoO/Co_3O_4 outer layer tends to disappear by reacting with the underlying rutile phase, which emerges at the surface. However, in cermets with higher Ta content, the formation of an external titanate layer, observed even at a low temperature, appears to prevent the oxygen diffusion and the oxidation progression.

  18. Rancang Bangun Ulang Aplikasi MonTA Menggunakan Workflow Framework pada ASP.NET

    Directory of Open Access Journals (Sweden)

    Mohammad Oktri Radity

    2013-09-01

    Full Text Available Zaman sekarang kemajuan teknologi semakin berkembang pesat dari tahun ke tahun. Kebutuhan orang terhadap teknologi menjadi sangat penting. Aplikasi MonTA yang digunakan oleh jurusan Teknik Informatika ITS menjadi bukti kemajuan teknologi. Aplikasi yang dikembangkan oleh jurusan Teknik Informatika ini bertujuan untuk mengelola seluruh data tugas akhir mahasiswa Teknik Informatika. Aplikasi MonTA merupakan suatu sistem yang berkaitan dengan tugas akhir mahasiswa di jurusan Teknik Informatika, Institut Teknologi Sepuluh Nopember Surabaya. Tujuan dikembangkannya aplikasi ini adalah untuk mengelola data mahasiswa yang melaksanakan tugas akhir dan dosen dapat memonitoring mahasiswa yang sedang melakukan tugas akhir dengan aplikasi ini. Aplikasi ini juga memudahkan admin tugas akhir dalam melakukan tugasnya, antara lain: penjadwalan proposal, memonitor jumlah bimbingan mahasiswa tugas akhir, penjadwalan sidang tugas akhir, dan lain-lain. Namun, aplikasi MonTA yang sekarang digunakan masih memiliki banyak kekurangan. Oleh karena itu dibahas perancangan ulang aplikasi MonTA pada artikel ini. Metode baru yang digunakan pada rancang ulang aplikasi MonTA ini adalah dengan penerapan Workflow Framework pada ASP.NET. Diharapkan dengan rancang ulang aplikasi ini nantinya dapat memperbaiki berbagai kekurangan yang ada saat ini, seperti inkonsitensi data dan memperbaiki data yang terdapat pada  aplikasi MonTA menjadi lebih terstruktur

  19. Structure and physical properties of Cr{sub 5}B{sub 3}-type Ta{sub 5}Si{sub 3} and Ta{sub 5}Ge{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Fang; Forbes, Scott [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1 (Canada); Ramachandran, Krishna Kumar [Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2 (Canada); Mozharivskyj, Yurij, E-mail: mozhar@mcmaster.ca [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1 (Canada)

    2015-11-25

    The Cr{sub 5}B{sub 3}-type Ta{sub 5}Si{sub 3} phase was prepared by arc-melting, while the Cr{sub 5}B{sub 3}-type Ta{sub 5}Ge{sub 3} one was synthesized through sintering at 1000 °C. X-ray single crystal diffraction was employed to elucidate their structure. According to the magnetization measurements, both Ta{sub 5}Si{sub 3} and Ta{sub 5}Ge{sub 3} are Pauli paramagnets, with Ta{sub 5}Ge{sub 3} showing a Curie-Weiss-like paramagnetic behavior at low temperatures likely due to presence of paramagnetic impurity. Both Ta{sub 5}Si{sub 3} and Ta{sub 5}Ge{sub 3} display a very low electrical resistivity from 2 to 300 K. The resistivity is constant below 20 K, but displays a positive temperature coefficient above 20 K. Electronic structure calculations with the TB-LMTO-ASA method support the metallic character of the two phases and suggest that the bonding is optimized in both phases. - Highlights: • Synthesis of Cr{sub 5}B{sub 3}-type Ta{sub 5}Si{sub 3} and Ta{sub 5}Ge{sub 3} phases with high purity by arc-melting and sintering, respectively. • Magnetization data and electrical resistivity of the Cr{sub 5}B{sub 3}-type Ta{sub 5}Si{sub 3} and Ta{sub 5}Ge{sub 3} phases. • Crystal and electronic structure analysis for Ta{sub 5}Si{sub 3} and Ta{sub 5}Ge{sub 3} phase by X-ray diffraction and TB-LMTO-ASA calculations.

  20. The influence of selective doping ions (Na{sup +}, Ta{sup 5+}) on the optoelectronic properties of WO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Enesca, A.; Duta, Anca [Transilvania University, The Centre: Product Design for Sustainable Development, Brasov (Romania)

    2013-05-15

    The influences of Na{sup +} and Ta{sup 5+} dopant ions on the properties of tungsten oxide films were studied by means of X-Ray Diffraction, Atomic Force Microscopy, and current voltage, photocurrent, and photoluminescence analysis. The results show that using dopant ions with higher radius will induce modification on the crystallite size and micro-strains. The samples with porous morphology (UW and NW) are characterized by higher roughness values (around 19 nm). The photosensitive properties of the samples are activated only in the presence of a bias with 0.5 V minimum value. (orig.)

  1. Use of reference samples for more accurate RBS analyses

    International Nuclear Information System (INIS)

    Lanford, W.A.; Pelicon, P.; Zorko, B.; Budnar, M.

    2002-01-01

    While one of the primary assets of RBS analysis is that it is quantitative without use of reference samples, for certain types of analyses the precision of the method can be improved by measuring RBS spectra of unknowns relative to the RBS spectra of a similar known sample. The advantage of such an approach is that one can reduce (or eliminate) the uncertainties that arise from error in the detector solid angle, beam current integration efficiency, scattering cross-section, and stopping powers. We have used this approach extensively to determine the composition (x) of homogeneous thin films of TaN x using as reference samples films of pure Ta. Our approach is to measure R=(Ta count) unknown /(Ta count) standard and use RUMP to determine the function x(R). Once the function x(R) has been determined, this approach makes it easy to analyze many samples quickly. Other analyses for which this approach has proved useful are determination of the composition (x) of WN x , SiO x H y and SiN x H y , using W, SiO 2 and amorphous Si as reference samples, respectively

  2. Effects of crystal structure and composition on the photocatalytic performance of Ta-O-N functional materials.

    Science.gov (United States)

    Liu, Qing-Lu; Zhao, Zong-Yan; Yi, Jian-Hong

    2018-05-07

    For photocatalytic applications, the response of a material to the solar spectrum and its redox capabilities are two important factors determined by the band gap and band edge position of the electronic structure of the material. The crystal structure and composition of the photocatalyst are fundamental for determining the above factors. In this article, we examine the functional material Ta-O-N as an example of how to discuss relationships among these factors in detail with the use of theoretical calculations. To explore how the crystal structure and composition influence the photocatalytic performance, two groups of Ta-O-N materials were considered: the first group included ε-Ta 2 O 5 , TaON, and Ta 3 N 5 ; the second group included β-Ta 2 O 5 , δ-Ta 2 O 5 , ε-Ta 2 O 5 , and amorphous-Ta 2 O 5 . Calculation results indicated that the band gap and band edge position are determined by interactions between the atomic core and valence electrons, the overlap of valence electronic states, and the localization of valence states. Ta 3 N 5 and TaON are suitable candidates for efficient photocatalysts owing to their photocatalytic water-splitting ability and good utilization efficiency of solar energy. δ-Ta 2 O 5 has a strong oxidation potential and a band gap suitable for absorbing visible light. Thus, it can be applied to photocatalytic degradation of most pollutants. Although a-Ta 2 O 5 , ε-Ta 2 O 5 , and β-Ta 2 O 5 cannot be directly used as photocatalysts, they can still be applied to modify conventional Ta-O-N photocatalysts, owing to their similar composition and structure. These calculation results will be helpful as reference data for analyzing the photocatalytic performance of more complicated Ta-O-N functional materials. On the basis of these findings, one could design novel Ta-O-N functional materials for specific photocatalytic applications by tuning the composition and crystal structure.

  3. Oxidation behaviors of the TiNi/Ti_2Ni matrix composite coatings with different contents of TaC addition fabricated on Ti6Al4V by laser cladding

    International Nuclear Information System (INIS)

    Lv, Y.H.; Li, J.; Tao, Y.F.; Hu, L.F.

    2016-01-01

    The TiNi/Ti_2Ni matrix composite coatings were fabricated on Ti6Al4V by laser cladding the mixtures of NiCrBSi and different contents of TaC (0 wt%, 5 wt%, 15 wt%, 30 wt% and 40 wt%). Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffractometry (XRD) were used to examine the microstructures of the coatings. Oxidation behaviors of these coatings were also investigated at 800 °C for 50 h in air. The results showed that the coating without TaC addition was mainly composed of TiNi/Ti_2Ni as the matrix and TiC/TiB_2/TiB as the reinforcement. TaC was dissolved completely and precipitated again during laser cladding. Ta and C from the added TaC mainly existed as the solute atoms in the solid solutions of TiC, TiB_2 and TiB in the coatings with TaC addition. The addition of TaC refined the microstructures of the coatings. In the oxidation test, the oxidation process was divided into the violent oxidation stage and the slow oxidation stage. The oxidation rates of the substrate and the coatings with different contents of TaC (0, 5, 15, 30, 40 wt%) were 0.644, 0.287, 0.173, 0.161, 0.223 and 0.072 mg cm"−"2 h"−"1 in the first stage, 0.884, 0.215, 0.136, 0.126, 0.108 and 0.040 mg"2 cm"−"4 h"−"1 in the second stage, respectively. The weight gain of these samples were 6.70, 3.30, 2.86, 2.64, 2.41 and 1.69 mg cm"−"2, respectively after the whole oxidation test. The oxidation film formed on the surface of the coating without TaC addition mainly consisted of TiO_2, Al_2O_3, and a small amount of NiO, Cr_2O_3 and SiO_2. Moreover, Ta_2O_5 was also formed on the surfaces of these coatings with different contents of TaC. The oxides formed during the oxidation test were supposed to be responsible for the improvement in oxidation resistance of these coatings. - Highlights: • The composite coatings with TaC addition were fabricated on Ti6Al4V by laser cladding. • Effect of TaC addition on microstructural evolution of the coatings was

  4. Oxidation behaviors of the TiNi/Ti{sub 2}Ni matrix composite coatings with different contents of TaC addition fabricated on Ti6Al4V by laser cladding

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Y.H.; Li, J., E-mail: jacob_lijun@sina.com; Tao, Y.F.; Hu, L.F.

    2016-09-15

    The TiNi/Ti{sub 2}Ni matrix composite coatings were fabricated on Ti6Al4V by laser cladding the mixtures of NiCrBSi and different contents of TaC (0 wt%, 5 wt%, 15 wt%, 30 wt% and 40 wt%). Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffractometry (XRD) were used to examine the microstructures of the coatings. Oxidation behaviors of these coatings were also investigated at 800 °C for 50 h in air. The results showed that the coating without TaC addition was mainly composed of TiNi/Ti{sub 2}Ni as the matrix and TiC/TiB{sub 2}/TiB as the reinforcement. TaC was dissolved completely and precipitated again during laser cladding. Ta and C from the added TaC mainly existed as the solute atoms in the solid solutions of TiC, TiB{sub 2} and TiB in the coatings with TaC addition. The addition of TaC refined the microstructures of the coatings. In the oxidation test, the oxidation process was divided into the violent oxidation stage and the slow oxidation stage. The oxidation rates of the substrate and the coatings with different contents of TaC (0, 5, 15, 30, 40 wt%) were 0.644, 0.287, 0.173, 0.161, 0.223 and 0.072 mg cm{sup −2} h{sup −1} in the first stage, 0.884, 0.215, 0.136, 0.126, 0.108 and 0.040 mg{sup 2} cm{sup −4} h{sup −1} in the second stage, respectively. The weight gain of these samples were 6.70, 3.30, 2.86, 2.64, 2.41 and 1.69 mg cm{sup −2}, respectively after the whole oxidation test. The oxidation film formed on the surface of the coating without TaC addition mainly consisted of TiO{sub 2}, Al{sub 2}O{sub 3}, and a small amount of NiO, Cr{sub 2}O{sub 3} and SiO{sub 2}. Moreover, Ta{sub 2}O{sub 5} was also formed on the surfaces of these coatings with different contents of TaC. The oxides formed during the oxidation test were supposed to be responsible for the improvement in oxidation resistance of these coatings. - Highlights: • The composite coatings with TaC addition were fabricated on Ti6Al4V by laser

  5. Reproducibility of Serum Potassium Values in Serum From Blood Samples Stored for Increasing Times Prior to Centrifugation and Analysis.

    Science.gov (United States)

    Harper, Aaron; Lu, Chuanyong; Sun, Yi; Garcia, Rafael; Rets, Anton; Alexis, Herol; Saad, Heba; Eid, Ikram; Harris, Loretta; Marshall, Barbara; Tafani, Edlira; Pincus, Matthew R

    2016-05-01

    The goal of this work was to determine if immediate versus postponed centrifugation of samples affects the levels of serum potassium. Twenty participants donated normal venous blood that was collected in four serum separator tubes per donor, each of which was analyzed at 0, 1, 2, or 4 hr on the Siemens Advia 1800 autoanalyzer. Coefficients of variation (CVs) for potassium levels ranged from 0% to 7.6% with a mean of 3 ± 2%. ANOVA testing of the means for all 20 samples showed a P-value of 0.72 (>0.05) indicating that there was no statistically significant difference between the means of the samples at the four time points. Sixteen samples were found to have CVs that were ≤5%. Two samples showed increases of potassium from the reference range to levels higher than the upper reference limit, one of which had a 4-hr value that was within the reference or normal range (3.5-5 mEq/l). Overall, most samples were found to have reproducible levels of serum potassium. Serum potassium levels from stored whole blood collected in serum separator tubes are, for the most part, stable at room temperature for at least 4 hr prior to analysis. However, some samples can exhibit significant fluctuations of values. © 2015 Wiley Periodicals, Inc.

  6. Quantitative characterization of spin-orbit torques in Pt/Co/Pt/Co/Ta/BTO heterostructures due to the magnetization azimuthal angle dependence

    Science.gov (United States)

    Engel, Christian; Goolaup, Sarjoosing; Luo, Feilong; Lew, Wen Siang

    2017-08-01

    Substantial understanding of spin-orbit interactions in heavy-metal (HM)/ferromagnet (FM) heterostructures is crucial in developing spin-orbit torque (SOT) spintronics devices utilizing spin Hall and Rashba effects. Though the study of SOT effective field dependence on the out-of-plane magnetization angle has been relatively extensive, the understanding of in-plane magnetization angle dependence remains unknown. Here, we analytically propose a method to compute the SOT effective fields as a function of the in-plane magnetization angle using the harmonic Hall technique in perpendicular magnetic anisotropy (PMA) structures. Two different samples with PMA, a Pt /Co /Pt /Co /Ta /BaTi O3 (BTO) test sample and a Pt/Co/Pt/Co/Ta reference sample, are studied using the derived formula. Our measurements reveal that only the dampinglike field of the test sample with a BTO capping layer exhibits an in-plane magnetization angle dependence, while no angular dependence is found in the reference sample. The presence of the BTO layer in the test sample, which gives rise to a Rashba effect at the interface, is ascribed as the source of the angular dependence of the dampinglike field.

  7. A wheat cinnamyl alcohol dehydrogenase TaCAD12 contributes to host resistance to the sharp eyespot disease

    Directory of Open Access Journals (Sweden)

    Wei Rong

    2016-11-01

    Full Text Available Sharp eyespot, caused mainly by the necrotrophic fungus Rhizoctonia cerealis, is a destructive disease in hexaploid wheat (Triticum aestivum L.. In Arabidopsis, certain cinnamyl alcohol dehydrogenases (CADs have been implicated in monolignol biosynthesis and in defense response to bacterial pathogen infection. However, little is known about CADs in wheat defense responses to necrotrophic or soil-borne pathogens. In this study, we isolate a wheat CAD gene TaCAD12 in response to R. cerealis infection through microarray-based comparative transcriptomics, and study the enzyme activity and defense role of TaCAD12 in wheat. The transcriptional levels of TaCAD12 in sharp eyespot-resistant wheat lines were significantly higher compared with those in susceptible wheat lines. The sequence and phylogenetic analyses revealed that TaCAD12 belongs to IV group in CAD family. The biochemical assay proved that TaCAD12 protein is an authentic CAD enzyme and possesses catalytic efficiencies towards both coniferyl aldehyde and sinapyl aldehyde. Knock-down of TaCAD12 transcript significantly repressed resistance of the gene-silenced wheat plants to sharp eyespot caused by R. cerealis, whereas TaCAD12 overexpression markedly enhanced resistance of the transgenic wheat lines to sharp eyespot. Furthermore, certain defense genes (Defensin, PR10, PR17c, and Chitinase1 and monolignol biosynthesis-related genes (TaCAD1, TaCCR, and TaCOMT1 were up-regulated in the TaCAD12-overexpressing wheat plants but down-regulated in TaCAD12-silencing plants. These results suggest that TaCAD12 positively contributes to resistance against sharp eyespot through regulation of the expression of certain defense genes and monolignol biosynthesis-related genes in wheat.

  8. Effect of chorionic villus sampling on the occurrence of preeclampsia and gestational hypertension: An updated systematic review and meta-analysis.

    Science.gov (United States)

    Başaran, Ahmet; Başaran, Mustafa; Topatan, Betül; Martin, James N

    2016-01-01

    To perform a meta-analysis for an assessment of the risk of preeclampsia or gestational hypertension following chorionic villus sampling (CVS). PubMed was systematically searched from its inception through January 2016. Nine reports were identified. A pre-specified scale was used to assess their quality. We performed pooling into three subgroups with respect to the control group: A) Patients with no invasive prenatal diagnostic procedure served as a control group for comparison. The odds ratios for gestational hypertension (0.76, 95% CI 0.46-1.26), preeclampsia (0.83, 95% CI 0.42-1.67), and severe preeclampsia (0.49, 95% CI 0.04-5.78) or when hypertension categories were pooled (0.80, 95% CI 0.46-1.41) were not significantly different. B) Patients with midtrimester diagnostic amniocentesis and patients with no invasive prenatal diagnostic procedure were combined as a control group for comparison. The odds ratios for preeclampsia (1, 95% CI 0.46-2.18), severe preeclampsia (0.83, 95% CI 0.14-4.85), and pooled hypertension categories (1.07, 95% CI 0.63-1.84) were not significantly different. C) Patients with midtrimester diagnostic amniocentesis served as a control group. There was a significant difference in the odds ratio for preeclampsia between the CVS and amniocentesis groups (2.47, 95% CI 1.14-5.33). There was a marginal difference in the odds ratio for combined pregnancy-induced hypertension categories between the CVS and amniocentesis groups (1.61, 95% CI 1.02-2.53). The available data do not indicate an increased risk of preeclampsia or gestational hypertension following first trimester CVS. The heterogeneity and retrospective design of existing studies are limiting factors for our analysis and findings.

  9. Comparison of physiochemical changes in two popular strawberry cultivars grown in Iran (cvs. Kurdistan & Selva during storage time at 4°C

    Directory of Open Access Journals (Sweden)

    Jouki Mohammad

    2012-01-01

    Full Text Available In this study the effect of storage time on some quality parameters of two strawberry cultivars fruits storage at 4°C have been evaluated. Several quality parameters were monitored during the storage period. The samples were analyzed 1, 7, 14 and 21days during storage. Fruits were analyzed about fruit weight, sugar content, chromatic parameters L*, a*, b*, fruit firmness, total titrable acidity, pH, and sensory evaluation. The Kurdistan strawberries retained their weight throughout the experiment as opposed to the Selva strawberries which lost 0.6% of their weight per day because of dehydration. The Selva cultivar was exceptionally firmer than Kurdistan strawberries. Two cultivars were rich in vitamin C and sugar but these values were more in Kurdistan cultivar. As expected, Chroma decreased and over the storage time in two cultivars. The results of this study showed that packaged Kurdistan strawberries could prove suitable for 7 days at 4°C compare with 4 days for selva strawberries.

  10. Superconductivity and specific heat measurements in V--Nb--Ta ternary alloys

    International Nuclear Information System (INIS)

    Wang, R.Y.P.

    1977-01-01

    The correlation between the superconducting transition temperature T/sub c/ with electronic specific heat coefficient γ and Debye temperature theta/sub D/ in some isoelectronic ternary V--Nb--Ta alloys is investigated. It has been known that the variation of theta/sub D/ with concentration in both V--Nb and V--Ta systems is clearly of the same curvature as that of T/sub c/ and γ. In Ta--Nb alloys, however, over most of the concentration range theta/sub D/ seems to have a slight negative curvature while T/sub c/ and γ curve upwards. (But beyond approx. 80 at. % Nb theta/sub D/ rises rapidly to the pure Nb value.) By choosing alloys along a line connecting Ta and V 25 --Nb 75 which is close to the Nb--Ta side of the Gibb's triangle the extent to which the Nb--Ta type of behavior persists in this ternary system can be estimated. A model proposed by Miedema that takes into account the variation of properties caused by possible charge transfer among constituent atoms in an alloy has been found to apply almost quantitatively for nearly all binary alloy systems whose experimental data are available, including those for which Hopfield's method fails. A previous test of the extension of Miedema's empirical model into ternary alloys shows qualitatively correct behavior for intra-row Zr/sub x/Nb/sub 1-2x/Mo/sub x/ alloys. The good agreement between the predicted values of γ and T/sub c/ and the experimental values in the inter-row ternary V--Nb--Ta system studied here gives another and better test of the application of Miedema's model

  11. Highly uniform ultraviolet-A quantum-confined AlGaN nanowire LEDs on metal/silicon with a TaN interlayer

    KAUST Repository

    Priante, Davide; Janjua, Bilal; Prabaswara, Aditya; Subedi, Ram Chandra; Elafandy, Rami T.; Lopatin, Sergei; Anjum, Dalaver H.; Zhao, Chao; Ng, Tien Khee; Ooi, Boon S.

    2017-01-01

    In this paper, we describe ultraviolet-A (UV-A) light-emitting diodes (LEDs) emitting at 325 nm based on a highly uniform structure of quantum-confined AlGaN quantum-disk nanowires (NWs). By incorporating a 20 nm TaN interlayer between a Ti pre-orienting layer and the silicon substrate, we eliminated the potential barrier for carrier injection and phonon transport, and inhibited the formation of interfacial silicide that led to device failure. Compared to previous reports on metal substrate, we achieved a 16 × reduction in root-mean-square (RMS) roughness, from 24 nm to 1.6 nm, for the samples with the Ti/TaN metal-bilayer, owing to the effective diffusion barrier characteristic of TaN. This was confirmed using energy dispersive X-ray spectroscopy (EDXS) and electron energy loss spectroscopy (EELS). We achieved a considerable increase in the injection current density (up to 90 A/cm2) compared to our previous studies, and an optical power of 1.9 μW for the 0.5 × 0.5 mm2 NWs-LED. This work provides a feasible pathway for both a reliable and stable UV-A device operation at elevated current injection, and eventually towards low-cost production of UV devices, leveraging on the scalability of silicon substrates.

  12. Highly uniform ultraviolet-A quantum-confined AlGaN nanowire LEDs on metal/silicon with a TaN interlayer

    KAUST Repository

    Priante, Davide

    2017-11-02

    In this paper, we describe ultraviolet-A (UV-A) light-emitting diodes (LEDs) emitting at 325 nm based on a highly uniform structure of quantum-confined AlGaN quantum-disk nanowires (NWs). By incorporating a 20 nm TaN interlayer between a Ti pre-orienting layer and the silicon substrate, we eliminated the potential barrier for carrier injection and phonon transport, and inhibited the formation of interfacial silicide that led to device failure. Compared to previous reports on metal substrate, we achieved a 16 × reduction in root-mean-square (RMS) roughness, from 24 nm to 1.6 nm, for the samples with the Ti/TaN metal-bilayer, owing to the effective diffusion barrier characteristic of TaN. This was confirmed using energy dispersive X-ray spectroscopy (EDXS) and electron energy loss spectroscopy (EELS). We achieved a considerable increase in the injection current density (up to 90 A/cm2) compared to our previous studies, and an optical power of 1.9 μW for the 0.5 × 0.5 mm2 NWs-LED. This work provides a feasible pathway for both a reliable and stable UV-A device operation at elevated current injection, and eventually towards low-cost production of UV devices, leveraging on the scalability of silicon substrates.

  13. Early deuteration steps of Pd- and Ta/Pd- catalyzed Mg{sub 70}Al{sub 30} thin films observed at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Harrower, Christopher; Kalisvaart, Peter; Mitlin, David [Chemical and Materials Engineering, University of Alberta, Alberta T6G 2V4 (Canada); National Research Council Canada, National Institute for Nanotechnology, Edmonton, Alberta T6G 2M9 (Canada); Poirier, Eric; Fritzsche, Helmut [National Research Council Canada, SIMS, Canadian Neutron Beam Centre, Chalk River, Ontario K0J 1J0 (Canada); Satija, Sushil [National Institute of Standards and Technology, Center for Neutron Research, Gaithersburg, MD 20899 (United States); Akgun, Bulent [National Institute of Standards and Technology, Center for Neutron Research, Gaithersburg, MD 20899 (United States); Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742 (United States)

    2010-10-15

    Deuterium absorption in Mg{sub 70}Al{sub 30} thin films coated with a Pd layer and a Ta/Pd bilayer were investigated using in situ neutron reflectometry at room temperature and deuterium pressures up to 1.3 bar. The approach used provides a detailed profile, at the nanoscale, of the deuterium content inside the specific layers that constitute the films. It is found that Mg{sub 70}Al{sub 30} can store up to 5 wt.% under these mild conditions following a two-step mechanism. The latter involves the deuteration of the top and bottom catalyst layers first, followed by the main Mg{sub 70}Al{sub 30} layer. The presence of deuterium throughout the films in the early absorption stages evidences atomic deuterium spillover from the catalyst layers. The addition of a Ta layer between the Pd and Mg{sub 70}Al{sub 30} was found to allow observable absorption at a pressure 10 times lower than on the Ta-free sample, without affecting the storage capacity. Our measurements imply that this improvement in kinetics is due to a lowering of the nucleation barrier for the formation of the hydride phase in the Mg{sub 70}Al{sub 30} layer. (author)

  14. Sintering study and properties of alumina matrix composites reinforced with NbC, TiC and TaC

    International Nuclear Information System (INIS)

    Tonello, K.P.S.; Trombini, V.; Bressiani, A.H.A.; Bressiani, J.C.

    2011-01-01

    Al_2O_3 based composite materials are very promising due to their good mechanical properties, and have been studied as an alternative for the production of materials with high wear resistance. In alumina based composites the addition of carbides can change and improve the sintering and mechanical properties of materials. The objective was to study the effect of adding small concentrations of NbC, TaC and TiC in the sintering, microstructure and mechanical properties of alumina composites. The sintering study was conducted in dilatometer, with heating rate of 20 ° C / min. up to 1800 ° C, and the study of microstructure and properties of the composites was performed in hot pressed samples, sintered at 1500°C/30min with constant pressure of 20MPa. The results indicated that the addition of carbides modified the sintering behavior and also indicated that the hardness and fracture toughness were improved by the presence of carbide particles. (author)

  15. Chromosomal distribution of pTa-535, pTa-86, pTa-713, 35S rDNA repetitive sequences in interspecific hexaploid hybrids of common wheat (Triticum aestivum L.) and spelt (Triticum spelta L.).

    Science.gov (United States)

    Goriewa-Duba, Klaudia; Duba, Adrian; Kwiatek, Michał; Wiśniewska, Halina; Wachowska, Urszula; Wiwart, Marian

    2018-01-01

    Fluorescent in situ hybridization (FISH) relies on fluorescent-labeled probes to detect specific DNA sequences in the genome, and it is widely used in cytogenetic analyses. The aim of this study was to determine the karyotype of T. aestivum and T. spelta hybrids and their parental components (three common wheat cultivars and five spelt breeding lines), to identify chromosomal aberrations in the evaluated wheat lines, and to analyze the distribution of polymorphisms of repetitive sequences in the examined hybrids. The FISH procedure was carried out with four DNA clones, pTa-86, pTa-535, pTa-713 and 35S rDNA used as probes. The observed polymorphisms between the investigated lines of common wheat, spelt and their hybrids was relatively low. However, differences were observed in the distribution of repetitive sequences on chromosomes 4A, 6A, 1B and 6B in selected hybrid genomes. The polymorphisms observed in common wheat and spelt hybrids carry valuable information for wheat breeders. The results of our study are also a valuable source of knowledge about genome organization and diversification in common wheat, spelt and their hybrids. The relevant information is essential for common wheat breeders, and it can contribute to breeding programs aimed at biodiversity preservation.

  16. Chromosomal distribution of pTa-535, pTa-86, pTa-713, 35S rDNA repetitive sequences in interspecific hexaploid hybrids of common wheat (Triticum aestivum L. and spelt (Triticum spelta L..

    Directory of Open Access Journals (Sweden)

    Klaudia Goriewa-Duba

    Full Text Available Fluorescent in situ hybridization (FISH relies on fluorescent-labeled probes to detect specific DNA sequences in the genome, and it is widely used in cytogenetic analyses. The aim of this study was to determine the karyotype of T. aestivum and T. spelta hybrids and their parental components (three common wheat cultivars and five spelt breeding lines, to identify chromosomal aberrations in the evaluated wheat lines, and to analyze the distribution of polymorphisms of repetitive sequences in the examined hybrids. The FISH procedure was carried out with four DNA clones, pTa-86, pTa-535, pTa-713 and 35S rDNA used as probes. The observed polymorphisms between the investigated lines of common wheat, spelt and their hybrids was relatively low. However, differences were observed in the distribution of repetitive sequences on chromosomes 4A, 6A, 1B and 6B in selected hybrid genomes. The polymorphisms observed in common wheat and spelt hybrids carry valuable information for wheat breeders. The results of our study are also a valuable source of knowledge about genome organization and diversification in common wheat, spelt and their hybrids. The relevant information is essential for common wheat breeders, and it can contribute to breeding programs aimed at biodiversity preservation.

  17. Nanodiamond embedded ta-C composite film by pulsed filtered vacuum arc deposition from a single target

    Science.gov (United States)

    Iyer, Ajai; Etula, Jarkko; Ge, Yanling; Liu, Xuwen; Koskinen, Jari

    2016-11-01

    Detonation Nanodiamonds (DNDs) are known to have sp3 core, sp2 shell, small size (few nm) and are gaining importance as multi-functional nanoparticles. Diverse methods have been used to form composites, containing detonation nanodiamonds (DNDs) embedded in conductive and dielectric matrices for various applications. Here we show a method, wherein DND-ta-C composite film, consisting of DNDs embedded in ta-C matrix have been co-deposited from the same cathode by pulsed filtered cathodic vacuum arc method. Transmission Electron Microscope analysis of these films revel the presence of DNDs embedded in the matrix of amorphous carbon. Raman spectroscopy indicates that the presence of DNDs does not adversely affect the sp3 content of DND-ta-C composite film compared to ta-C film of same thickness. Nanoindentation and nanowear tests indicate that DND-ta-C composite films possess improved mechanical properties in comparison to ta-C films of similar thickness.

  18. Crystal structure of the mixed-metal trisulfide BaCu1/3Ta2/3S3

    Directory of Open Access Journals (Sweden)

    Kejun Bu

    2017-05-01

    Full Text Available The mixed-metal title compound, BaCu1/3Ta2/3S3 [barium copper(II tantalum(V trisulfide], was prepared through solid-state reactions. The crystal structure adopts the BaTaS3 structure type and consists of face-sharing [MS6] (M = Ta,Cu octahedra (point-group symmetry -3m. that are condensed into infinite chains along [001]. Adjacent chains are linked through the barium cations (site symmetry -6m2, which exhibit a coordination number of twelve. The M site is occupied by 2/3 of TaV and 1/3 of CuII, whereby the average M—S distances are slightly longer than those of ordered BaTaS3. The classical charge balance of the title compound can be represented by [Ba2+] [(Ta/Cu4+] [S2−]3.

  19. Mechanisms of Low-Temperature Nitridation Technology on a TaN Thin Film Resistor for Temperature Sensor Applications.

    Science.gov (United States)

    Chen, Huey-Ru; Chen, Ying-Chung; Chang, Ting-Chang; Chang, Kuan-Chang; Tsai, Tsung-Ming; Chu, Tian-Jian; Shih, Chih-Cheng; Chuang, Nai-Chuan; Wang, Kao-Yuan

    2016-12-01

    In this letter, we propose a novel low-temperature nitridation technology on a tantalum nitride (TaN) thin film resistor (TFR) through supercritical carbon dioxide (SCCO2) treatment for temperature sensor applications. We also found that the sensitivity of temperature of the TaN TFR was improved about 10.2 %, which can be demonstrated from measurement of temperature coefficient of resistance (TCR). In order to understand the mechanism of SCCO2 nitridation on the TaN TFR, the carrier conduction mechanism of the device was analyzed through current fitting. The current conduction mechanism of the TaN TFR changes from hopping to a Schottky emission after the low-temperature SCCO2 nitridation treatment. A model of vacancy passivation in TaN grains with nitrogen and by SCCO2 nitridation treatment is eventually proposed to increase the isolation ability in TaN TFR, which causes the transfer of current conduction mechanisms.

  20. 180Ta/sup g,m/ production cross sections form the 180Hf(p,n) reaction

    International Nuclear Information System (INIS)

    Norman, E.B.; Renner, T.R.; Grant, P.J.

    1981-01-01

    Cross sections have been determined for the production of the J/sup π/ = 1 + 180 Ta/sup g/ and the J/sup π/= 9 - 180 Ta/sup m/ from the 180 Hf(p,n) reaction. The 180 Ta/sup g/ cross sections were determined from measurements of γ-rays emitted following the electron-capture and β-decay of this 8.1-hour state. Total 180 Ta production cross sections were determined from measurements of the thick-target (p,n) yield. 180 Ta/sup m/ cross sections were calculated by subtracting the 180 Ta/sup g/ cross sections from the total (p,n) cross sections. These measurements are compared with the results of a statistical-model evaporation calculation