WorldWideScience

Sample records for russian-american gallium experiment

  1. The Russian-American Gallium solar neutrino Experiment

    International Nuclear Information System (INIS)

    Elliott, S.R.; Abdurashitov, J.N.

    1995-01-01

    The Russian-American Gallium solar neutrino Experiment (SAGE) is described. The solar neutrino flux measured by 31 extractions through October, 1993 is presented. The result of 69 ± 10 -7 +5 SNU is to be compared with a standard solar model prediction of 132 SNU. The status of a 51 Cr neutrino source irradiation to test the overall operation of the experiment is also presented

  2. The Russian-American Gallium solar neutrino Experiment (SAGE)

    International Nuclear Information System (INIS)

    Bowles, T.J.

    1994-01-01

    The Russian-American Gallium Experiment (SAGE) began measurements of the integral flux of solar neutrinos using 30 tons of metallic gallium as the target in January 1990. The mass of the gallium was increased to 57 tons in September 1991 and SAGE began to count the decay of 71 Ge using both the K and L peaks in September 1992. The results indicate a deficit of about 40% of the flux predicted by the Standard Solar Model. The chemical extraction and counting techniques used by SAGE are presented, with particular attention on backgrounds. The present status, results, and future plans of SAGE are presented, along with a discussion of the possible physics implications

  3. The status of the solar neutrino problem and the Russian-American gallium experiment (SAGE)

    International Nuclear Information System (INIS)

    Bowles, T.J.

    1994-01-01

    Perhaps the most outstanding discrepancy between prediction and measurements in current particle physics comes from the solar neutrino problem, in which a large deficit of high-energy solar neutrinos is observed. Many Nonstandard Solar Models have been invoked to try to reduce the predicted flux, but all have run into problems in trying to reproduce other measured parameters (e.g., the luminosity) of the Sun. Other explanations involving new physics such as neutrino decay and neutrino oscillations, etc. have also been proffered. Again, most of these explanations have been ruled out by either laboratory or astrophysical measurements. It appears that perhaps the most likely particle physics solution is that of matter enhanced neutrino oscillation, the Mikheyev-Smirnov-Wolfenstein (MSW) oscillations. Two new radiochemical gallium experiments, which have a low enough threshold to be sensitive to the dominant flux of low-energy p-p neutrinos, now also report a deficit and also favor a particle physics solution

  4. Measurement of solar neutrinos flux in Russian-American gallium experiment SAGE for half 22-years cycle of solar activity

    International Nuclear Information System (INIS)

    Abdurashitov, D.N.; Veretenkin, E.P.; Vermul, V.M.

    2002-01-01

    The results of measuring the solar neutrino capture on the metallic gallium in the Russian-American experiment SAGE for the period slightly exceeding the half of the 22-year cycle of solar activity, are presented. The results of new measurements since April 1998 are quoted and the analysis of all the measurements, performed by years, months and two-year periods, beginning since 1990 are also presented. Simple analysis of the SAGE results together with the results of other solar neutrino experiments leads to estimating the value of the flux of the pp-neutrinos, reaching the Earth without change in their around, equal to (4.6 ± 1.2) x 10 10 neutrino/(cm 2 s). The value of the flux of the pp-neutrinos, originating in the Sun thermonuclear reactions, is equal to (7.6 ± 2.0) x 10 10 neutrino/(cm 2 s), which agrees well with the standard solar model (5.95 ± 0.6) x 10 10 neutrino/(cm 2 s) [ru

  5. Russian-American Experience in Science Education and Volcanological Research

    Science.gov (United States)

    Eichelberger, J. C.; Gordeev, E. I.; Vesna, E. B.

    2007-12-01

    After five years experience in bringing American students to meet and learn with Russian students in Kamchatka and bringing Russian students to meet and learn with American students in Alaska, it is possible to make some generalizations about the problems and benefits this growing program. Some 200 students, including many from other countries besides the United States and Russian Federation, have now had this experience. The context of their collaboration is the International Volcanological Field School, sponsored by the University of Alaska Fairbanks, Kamchatka State University, and the Institute of Volcanology and Seismology, and also a comparison of Mount St Helens, Bezymianny, and Shiveluch volcanoes under the National Science Foundation's Partnerships in International Research in Education, with important support from the Russian Academy of Sciences, Far East Division. Elements of these two projects are adaptation to unfamiliar, harsh, and remote environments; intensive courses in Russian language, history, geography, and culture; and sharing of research and education experiences among students. The challenges faced by the program are: · Slow and complex visa processes. · Demise of a direct airline connection, necessitating round-the-world travel to go 3000 km. · Adequately communicating to students beforehand the need for physical fitness, mental fortitude in uncomfortable conditions, and patience when bad weather limits mobility. Benefits of the projects have been: · Experiences that students report to be career- and life-changing. · Much more positive perceptions of Russia and Russian people by American students and of America and Americans by Russian students. · Introduction to the "expedition style" volcanology necessary in challenging environments. · Development of long-lasting collaborations and friendships in the context of international science. Students often comment that hearing about what their peers have done or are doing in research at

  6. Gallium

    Science.gov (United States)

    Foley, Nora K.; Jaskula, Brian W.; Kimball, Bryn E.; Schulte, Ruth F.; Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.

    2017-12-19

    Gallium is a soft, silvery metallic element with an atomic number of 31 and the chemical symbol Ga. Gallium is used in a wide variety of products that have microelectronic components containing either gallium arsenide (GaAs) or gallium nitride (GaN). GaAs is able to change electricity directly into laser light and is used in the manufacture of optoelectronic devices (laser diodes, light-emitting diodes [LEDs], photo detectors, and solar cells), which are important for aerospace and telecommunications applications and industrial and medical equipment. GaAs is also used in the production of highly specialized integrated circuits, semiconductors, and transistors; these are necessary for defense applications and high-performance computers. For example, cell phones with advanced personal computer-like functionality (smartphones) use GaAs-rich semiconductor components. GaN is used principally in the manufacture of LEDs and laser diodes, power electronics, and radio-frequency electronics. Because GaN power transistors operate at higher voltages and with a higher power density than GaAs devices, the uses for advanced GaN-based products are expected to increase in the future. Gallium technologies also have large power-handling capabilities and are used for cable television transmission, commercial wireless infrastructure, power electronics, and satellites. Gallium is also used for such familiar applications as screen backlighting for computer notebooks, flat-screen televisions, and desktop computer monitors.Gallium is dispersed in small amounts in many minerals and rocks where it substitutes for elements of similar size and charge, such as aluminum and zinc. For example, gallium is found in small amounts (about 50 parts per million) in such aluminum-bearing minerals as diaspore-boehmite and gibbsite, which form bauxite deposits, and in the zinc-sulfide mineral sphalerite, which is found in many mineral deposits. At the present time, gallium metal is derived mainly as a

  7. The Soviet-American gallium experiment (SAGE)

    International Nuclear Information System (INIS)

    Garvey, G.T.

    1989-01-01

    The Soviet-American Gallium Experiment (SAGE) undertaking is a multi-institutional collaboration among scientists from the Institute for Nuclear Research, Moscow (INR), Los Alamos National Laboratory (LANL), and several US universities. It's purpose is to measure the number of low-energy electron neutrinos emitted from the Sun that arrive at this planet. As such, it is an extremely important experiment, touching on fundamental physics issues as well as solar dynamics. In contrast to the strategic overviews, plans, and hopes for intentional collaboration presented earlier today, SAGE is an ongoing working effort with high hopes of producing the first measurement of the Sun's low-energy flux. There are several international physics collaborations involving US and Soviet scientists at the large accelerator installations throughout the world. As the scale of research gets ever larger, requiring ever more resources and then larger collaborations. Much physics research lies solely in the realm of basic research so that governments feel easier about collaborations. Contacts between the US and USSR scientists interested in nuclear and particle physics goes back to the nineteen fifties and have continued with only minor interruptions since then. Over the past two decades the principal oversight of these activities has been through the Joint Coordinating Committee on the Fundamental Properties of Matter, supported by the DOE in the US and the State Committee for Atomic Energy in the USSR. The Academies of Science of both countries have been very helpful and supportive. Each venture has some distinguishing features; in the case of SAGE, the unique aspects are the collaboration between Soviet scientists and scientists at a DOE weapons laboratory and the fact that the experiment is carried out in a remote region of the USSR. The particular problems caused are discussed. 3 refs., 3 figs

  8. First results from the Soviet-American Gallium Experiment

    International Nuclear Information System (INIS)

    Abazov, A.I.; Abdurashitov, D.N.; Anosov, O.L.; Eroshkina, L.A.; Faizov, E.L.; Gavrin, V.N.; Kalikhov, A.V.; Knodel, T.V.; Knyshenko, I.I.; Kornoukhov, V.N.; Mezentseva, S.A.; Mirmov, I.N.; Ostrinsky, A.I.; Petukhov, V.V.; Pshukov, A.M.; Revzin, N.Y.; Shikhin, A.A.; Timofeyev, P.V.; Veretenkin, E.P.; Vermul, V.M.; Zakharov, Y.; Zatsepin, G.T.; Zhandarov, V.I.; Davis, R. Jr.; Lande, K.; Cherry, M.L.; Kouzes, R.T.

    1990-01-01

    The Soviet-American Gallium Experiment is the first experiment able to measure the dominant flux of low energy p-p solar neutrinos. Four extractions made during January to May 1990 from 30 tons of gallium have been counted and indicate that the flux is consistent with 0 SNU and is less than 72 SNU (68% CL) and less than 138 SNU (95% CL). This is to be compared with the flux of 132 SNU predicted by the Standard Solar Model. 10 refs., 4 figs., 1 tab

  9. Status of the Soviet-American gallium experiment

    International Nuclear Information System (INIS)

    Anosov, O.L.; Faizov, E.L.; Gavrin, V.N.; Kalikhov, A.V.; Knodel, T.V.; Knyshenko, I.I.; Kornoukhov, V.N.; Mirmov, I.N.; Ostrinsky, A.V.; Pshukov, A.M.; Shikhin, A.A.; Timofeyev, P.V.; Veretenkin, E.P.; Vermul, V.M.; Zatsepin, G.T.; Cherry, M.L.; Cleveland, B.T.; Davis, R. Jr.; Lande, K.; Kouzes, R.T.

    1993-01-01

    A radiochemical 71 Ga- 71 Ge experiment to determine the primary flux of neutrinos from the Sun began measurements of the solar neutrino flux at the Baksan Neutrino Observatory in 1990. The number of 71 Ge atoms extracted from 30 tons of gallium in 1990 and from 57 tons of gallium in 1991 was measured in twelve runs during the period of January 1990 to December 1991. The combined 1990 and 1991 data sets give a value of 58 + 17/ - 24 (stat.) ± 14 (syst.) SNU. This is to be compared with 132 SNU predicted by the Standard Solar Model. 2 tabs, 1 fig, 14 refs

  10. Latest results from the Soviet-American gallium experiment

    International Nuclear Information System (INIS)

    Gavrin, V.N.; Anosov, O.L.; Faizov, E.L.; Kalikhov, A.V.; Knodel, T.V.; Knyshenko, I.I.; Kornoukhov, V.N.; Mirmov, I.N.; Ostrinsky, A.V.; Pshukov, A.M.; Shikhin, A.A.; Timofeyev, P.V.; Veretenkin, E.P.; Vermul, V.M.; Zatsepin, G.T.; Bowles, T.J.; Elliott, S.R.; Nico, J.S.; O'Brien, H.A.; Wark, D.L.; Wilkerson, J.F.; Cleveland, B.T.; Davis, R. Jr.; Lande, K.; Cherry, M.L.; Kouzes, R.T.

    1992-01-01

    A radiochemical 71 Ga- 71 Ge experiment to determine the primary flux of neutrinos from the Sun began measurements of the solar neutrino flux at the Baksan Neutrino Observatory in 1990. The number of 71 Ge atoms extracted from 30 tons of gallium in 1990 and from 57 tons of gallium in 1991 was measured in twelve runs during the period of January 1990 to December 1991. The combined 1990 and 1991 data sets give a value of 58+17/-24 (stat)±14 (syst) SNU. This is to be compared with 132 SNU predicted by the Standard Solar Model

  11. Excerpt from Transnational Russian-American Travel Writing

    Directory of Open Access Journals (Sweden)

    Margarita D. Marinova

    2012-06-01

    Full Text Available Margarita Marinova’s text is excerpted from her new work Transnational Russian-American Travel Writing. The work’s purpose is to examine “the diverse practices of crossing boundaries, tactics of translation, and experiences of double and multiple political and national attachments” found in a group of writings about encounters between Russians and Americans between 1865 and the Russian Revolution of 1905. (These encounters provide a prelude to the more famous American travelogue of 1930s Soviet satirical writers Ilya Ilf and Evgeny Petrov, Odnoetazhnaia Amerika [Single-Storied America]. Contrasting viewpoints on race and ethnicity form an important element of Marinova’s corpus, and one fine example is the extract shown here, which treats the encounter of Russian-Jewish revolutionary Vladimir Bogoraz (Tan with a Black American student working as a Pullman porter, and the Russian’s unwittingly humorous incapacity to view him outside of stereotypes (in a fashion that anticipates the character of the mother in Shirley Jackson’s mordant short story “After You, My Dear Alphonse”.

  12. The Baksan Neutrino Observatory Soviet-American Gallium Solar Neutrino Experiment

    International Nuclear Information System (INIS)

    Abazov, A.I.; Abdurashitov, D.N.; Anosov, O.V.

    1988-01-01

    A radiochemical 71 Ga- 71 Ge experiment to determine the integral flux of neutrinos from the sun is currently under preparation at the Baksan Neutrino Observatory in the USSR. Measurements are scheduled to commence by late 1988 with 30 tonnes of metallic gallium. A fractional statistical accuracy of 18% is expected to be obtained after one year of operation if the solar signal obtained after one year of operation if the solar signal is 70 SNU, the flux expected from p-p neutrinos alone. While initial measurements are in progress, 30 additional tonnes of gallium will be installed in order to perform the full experiment with a 60-tonne target. 28 refs

  13. Measurement of solar proton-proton fusion neutrinos with a Soviet-American gallium experiment: Technical progress report

    International Nuclear Information System (INIS)

    Cherry, M.L.

    1989-06-01

    A gallium solar neutrino detector is sensitive to low-energy proton-proton fusion neutrinos. A flux of 70 SNU is expected in a gallium detector from the p-p reaction independent of solar model calculations. If, however, neutrino oscillations in the solar interior are responsible for the suppressed 8 B flux measured by the Homestake 37 Cl experiment, then a comparison of the gallium and chlorine results may make possible a determination of the neutrino mass difference and mixing angle. A 60-ton gallium detector is currently being constructed in the Baksan Laboratory in the Soviet Union, and should be taking data by the end of 1989

  14. The mobility of indium and gallium in groundwater systems: constraining the role of sorption in sand column experiments

    Science.gov (United States)

    Dror, I.; Ringering, K.; Yecheskel, Y.; Berkowitz, B.

    2017-12-01

    The mobility of indium and gallium in groundwater environments was studied via laboratory experiments using quartz sand as a porous medium. Indium and gallium are metals of very low abundance in the Earth's crust and, correspondingly, the biosphere is only adapted to very small concentrations of these elements. However, in modern semiconductor industries, both elements play a central role and are incorporated in devices of mass production such as smartphones and digital cameras. The resulting considerable increase in production, use and discharge of indium and gallium throughout the last two decades, with a continuous and fast increase in the near future, raises questions regarding the fate of both elements in the environment. However, the transport behavior of these two metals in soils and groundwater systems remains poorly understood to date. Because of the low solubility of both elements in aqueous solutions, trisodium citrate was used as a complexation agent to stabilize the solutions, enabling investigation of the transport of these metals at neutral pH. Column experiments showed different binding capacities for indium and gallium, where gallium is much more mobile compared to indium and both metals are substantially retarded in the column. Different affinities were also confirmed by examining sorption isotherms of indium and gallium in equilibrium batch systems. The effect of natural organic matter on the mobility of indium and gallium was also studied, by addition of humic acid. For both metals, the presence of humic acid affects the sorption dynamics: for indium, sorption is strongly inhibited leading to much higher mobility, whereas gallium showed a slightly higher sorption affinity and very similar mobility compared to the same setup without humic acid addition. However, in all cases, the binding capacity of gallium to quartz is much weaker than that of indium. These results are consistent with the assumption that indium and gallium form different types

  15. Two years of on-orbit gallium arsenide performance from the LIPS solar cell panel experiment

    Science.gov (United States)

    Francis, R. W.; Betz, F. E.

    1985-01-01

    The LIPS on-orbit performance of the gallium arsenide panel experiment was analyzed from flight operation telemetry data. Algorithms were developed to calculate the daily maximum power and associated solar array parameters by two independent methods. The first technique utilizes a least mean square polynomial fit to the power curve obtained with intensity and temperature corrected currents and voltages; whereas, the second incorporates an empirical expression for fill factor based on an open circuit voltage and the calculated series resistance. Maximum power, fill factor, open circuit voltage, short circuit current and series resistance of the solar cell array are examined as a function of flight time. Trends are analyzed with respect to possible mechanisms which may affect successive periods of output power during 2 years of flight operation. Degradation factors responsible for the on-orbit performance characteristics of gallium arsenide are discussed in relation to the calculated solar cell parameters. Performance trends and the potential degradation mechanisms are correlated with existing laboratory and flight data on both gallium arsenide and silicon solar cells for similar environments.

  16. Investigations in gallium removal

    Energy Technology Data Exchange (ETDEWEB)

    Philip, C.V.; Pitt, W.W. [Texas A and M Univ., College Station, TX (United States); Beard, C.A. [Amarillo National Resource Center for Plutonium, TX (United States)

    1997-11-01

    Gallium present in weapons plutonium must be removed before it can be used for the production of mixed-oxide (MOX) nuclear reactor fuel. The main goal of the preliminary studies conducted at Texas A and M University was to assist in the development of a thermal process to remove gallium from a gallium oxide/plutonium oxide matrix. This effort is being conducted in close consultation with the Los Alamos National Laboratory (LANL) personnel involved in the development of this process for the US Department of Energy (DOE). Simple experiments were performed on gallium oxide, and cerium-oxide/gallium-oxide mixtures, heated to temperatures ranging from 700--900 C in a reducing environment, and a method for collecting the gallium vapors under these conditions was demonstrated.

  17. Investigations in gallium removal

    International Nuclear Information System (INIS)

    Philip, C.V.; Pitt, W.W.; Beard, C.A.

    1997-11-01

    Gallium present in weapons plutonium must be removed before it can be used for the production of mixed-oxide (MOX) nuclear reactor fuel. The main goal of the preliminary studies conducted at Texas A and M University was to assist in the development of a thermal process to remove gallium from a gallium oxide/plutonium oxide matrix. This effort is being conducted in close consultation with the Los Alamos National Laboratory (LANL) personnel involved in the development of this process for the US Department of Energy (DOE). Simple experiments were performed on gallium oxide, and cerium-oxide/gallium-oxide mixtures, heated to temperatures ranging from 700--900 C in a reducing environment, and a method for collecting the gallium vapors under these conditions was demonstrated

  18. Opportunities of Gallium Sage experiment with artificial neutrino sources for investigation of neutrino to sterile states

    International Nuclear Information System (INIS)

    Gavrin, V.N.; Gorbachiev, V.V.; Veretenkin, E.P.

    2011-01-01

    The unexpectedly low capture rate of neutrino in Ga source experiments in SAGE and GALLEX can be explained assuming electron neutrino transitions to sterile states with a mass-squared difference ∼ 1eV 2 . To test this oscillation hypothesis, we propose to place a very intense 51 Cr source at the center of a 50 tonne target of gallium metal that is divided into two zones and to measure the neutrino capture rate in each zone. The Experiment has the potential to test neutrino oscillation transitions with mass-squared difference Δm 2 > 0.5 eV 2 . An optimized SAGE setup and 3 MCi source of 51 Cr would provide a sensitivity to electron neutrino disappearance of a few percent.

  19. Neutrino oscillations in Gallium and reactor experiments and cosmological effects of a light sterile neutrino

    International Nuclear Information System (INIS)

    Acero-Ortega, Mario Andres

    2009-01-01

    Neutrino oscillations is a very well studied phenomenon and the observations from Solar, very-long-baseline Reactor, Atmospheric and Accelerator neutrino oscillation experiments give very robust evidence of three-neutrino mixing. On the other hand, some experimental data have shown anomalies that could be interpreted as indication of exotic neutrino physics beyond three-neutrino mixing. Furthermore, from a cosmological point of view, the possibility of extra light species contributing as a subdominant hot (or warm) component of the Universe is still interesting. In the first part of this Thesis, we focused on the anomaly observed in the Gallium radioactive source experiments. These experiments were done to test the Gallium solar neutrino detectors GALLEX and SAGE, by measuring the electron neutrino flux produced by intense artificial radioactive sources placed inside the detectors. The measured number of events was smaller than the expected one. We interpreted this anomaly as a possible indication of the disappearance of electron neutrinos and, in the effective framework of two-neutrino mixing, we obtained sin 2 2θ ≥ 0.03 and Δm 2 ≥ 0.1 eV 2 . We also studied the compatibility of this result with the data of the Bugey and Chooz reactor antineutrino disappearance experiments. We found that the Bugey data present a hint of neutrino oscillations with 0.02 ≤ sin 2 2θ ≤ 0.07 and Δm 2 ≅ 1.95 eV 2 , which is compatible with the Gallium allowed region of the mixing parameters. Then, combining the data of Bugey and Chooz, the data of Gallium and Bugey, and the data of Gallium, Bugey and Chooz, we found that this hint persists, with an acceptable compatibility of the experimental data. Furthermore, we analyzed the experimental data of the I.L.L., S.R.S, and Gosgen nuclear Reactor experiments. We obtained a good fit of the I.L.L. data, showing 1 and 2σ allowed regions in the oscillation parameters space. However, the combination of I.L.L. data with the Bugey

  20. Enrichment services for chromium isotopes for the GALLEX (gallium experiment) international collaboration experiment on solar neutrino flux

    Science.gov (United States)

    Szady, Andrew J.

    1990-07-01

    Detailed discussions were held with members of the Gallium Experiment (GALLEX) international solar neutrino research collaboration concerning negotiations to provide $1.4 million in services to enrich (50)Cr for a (51)Cr neutrino source. The source will be used to calibrate the 20-ton gallium solar neutrino detector currently in place in the Gran Sasso Laboratory in Italy. Funding approval for the enrichment services is expected from the European Common Market by October 19, 1990. The discussions focused on the technical aspects of the enrichment, the health and safety requirements for handling the process gas, cost projections, schedule, the Work-for-Others contract, and the method of payment. Discussions were also held with members of the Nuclear Physics Dept. at the University of Milan concerning the availability of isotopes enriched by the Calutron at the Oak Ridge National Laboratory. Very high purity material is needed to grow crystals for use in double beta decay detectors. Finally, working sessions were held to draft a coauthored paper on the results of using the gas centrifuge to remove trace quantities of (85)Kr from natural xenon.

  1. Low energy solar neutrino experiments: The Soviet American Gallium Experiment (SAGE). Final report, August 12, 1988--October 31, 1994

    International Nuclear Information System (INIS)

    1995-01-01

    Two 71 Ga experiments are currently in operation. The first is the 60 ton Soviet American Gallium Experiment (SAGE) at Baksan, which has recently reported a signal level of 73+18/-16(stat)+5/-7(syst) SNU; the second is the 30 ton GALLEX experiment at Gran Sasso, which sees 87±14±7 SNU. Both results are consistent, and both suggest a neutrino flux level low compared to the total expected from standard solar model calculations. It is not possible, however, to make a case for flux levels lower than the p-p prediction. Assuming the experiments are correct (Neutrino source calibrations are planned for both SAGE and GALLEX in the near future.), it is not at all clear yet whether the answer lies with the neutrino physics, solar physics, or a combination of both. Nevertheless, though solar model effects cannot be ruled out, if the Homestake and Kamiokande results are taken at face value, then these two experiments alone imply that neutrino oscillations or some similar particle physics result must be present to some degree. This report reviews the SAGE experiment and recent results. Non-radiochemical experiments are also discussed, with an emphasis on the Kamiokande water Cerenkov results

  2. Low energy solar neutrino experiments: The Soviet American Gallium Experiment (SAGE). Final report, August 12, 1988--October 31, 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-04-01

    Two {sup 71}Ga experiments are currently in operation. The first is the 60 ton Soviet American Gallium Experiment (SAGE) at Baksan, which has recently reported a signal level of 73+18/{minus}16(stat)+5/{minus}7(syst) SNU; the second is the 30 ton GALLEX experiment at Gran Sasso, which sees 87{+-}14{+-}7 SNU. Both results are consistent, and both suggest a neutrino flux level low compared to the total expected from standard solar model calculations. It is not possible, however, to make a case for flux levels lower than the p-p prediction. Assuming the experiments are correct (Neutrino source calibrations are planned for both SAGE and GALLEX in the near future.), it is not at all clear yet whether the answer lies with the neutrino physics, solar physics, or a combination of both. Nevertheless, though solar model effects cannot be ruled out, if the Homestake and Kamiokande results are taken at face value, then these two experiments alone imply that neutrino oscillations or some similar particle physics result must be present to some degree. This report reviews the SAGE experiment and recent results. Non-radiochemical experiments are also discussed, with an emphasis on the Kamiokande water Cerenkov results.

  3. Proof-of-Concept Experiments on a Gallium-Based Ignitron for Pulsed Power Applications

    Science.gov (United States)

    Ali, H. K.; Hanson, V. S.; Polzin, K. A.; Pearson, J. B.

    2015-01-01

    ignitron designs have used mercury as the liquid metal cathode, owing to its presence as a liquid at room temperatures and a vapor pressure of 10 Pa (75 mtorr) at room temperature. While these are favorable properties, there are obvious environmental and personal safety concerns with the storage, handling, and use of mercury and its compounds. The purpose of the present work was to fabricate and test an ignitron that used as its cathode an alternate liquid metal that was safe to handle and store. To that end, an ignitron test article that used liquid gallium as the cathode material was developed and tested. Gallium is a metal that has a melting temperature of 29.76 C, which is slightly above room temperature, and a boiling point of over 2,300 C at atmospheric pressure. This property makes gallium the element with the largest relative difference between melting and boiling points. Gallium has a limited role in biology, and when ingested, it will be subsequently processed by the body and expelled rather than accumulating to toxic levels. The next section of this Technical Memorandum (TM) provides background information on the development of mercury-based ignitrons, which serves as the starting point for the development of the gallium-based variant. Afterwards, the experimental hardware and setup used in proof-of-concept testing of a basic gallium ignitron are presented. Experimental data, consisting of discharge voltage and current waveforms as well as high-speed imaging of the gallium arc discharge in the gallium ignitron test article, are presented to demonstrate the efficacy of the concept. Discussion of the data and suggestions on improvements for future iterations of the design are presented in the final two sections of this TM.

  4. Solar neutrino flux measurements by the Soviet-American Gallium Experiment (SAGE) for half the 22-year solar cycle

    International Nuclear Information System (INIS)

    Abdurashitov, J.N.; Veretenkin, E.P.; Vermul, V.M.; Gavrin, V.N.; Girin, S.V.; Gorbachev, V.V.; Gurkina, P.P.; Zatsepin, G.T.; Ibragimova, T.V.; Kalikhov, A.V.; Knodel, T.V.; Mirmov, I.N.; Khairnasov, N.G.; Shikhin, A.A.; Yants, V.E.; Bowles, T.J.; Teasdale, W.A.; Nico, J.S.; Wilkerson, J.F.; Cleveland, B.T.

    2002-01-01

    We present measurements of the solar neutrino capture rate on metallic gallium in the Soviet-American gallium experiment (SAGE) over a period of slightly more than half the 22-year solar cycle. A combined analysis of 92 runs over the twelve-year period from January 1990 until December 2001 yields a capture rate of 70.8 +5.3 -5.2 (stat) +3.7 -3.2 (sys) SNU for solar neutrinos with energies above 0.233 MeV. This value is slightly more than half the rate predicted by the standard solar model, 130 SNU. We present the results of new runs since April 1998 and analyze all runs combined by years, months, and bimonthly periods beginning in 1990. A simple analysis of the SAGE results together with the results of other solar neutrino experiments gives an estimate of (4.6 ± 1.2) x 10 10 neutrinos cm -2 s -1 for the flux of the electron pp neutrinos that reach the Earth without changing their flavor. The flux of the pp neutrinos produced in thermonuclear reactions in the Sun is estimated to be (7.6 ± 2.0) x 10 10 neutrinos cm -2 s -1 , in agreement with the value of (5.95 ± 0.06) x 10 10 neutrinos cm -2 s -1 predicted by the standard solar model

  5. Gallium Safety in the Laboratory

    International Nuclear Information System (INIS)

    Cadwallader, L.C.

    2003-01-01

    A university laboratory experiment for the US Department of Energy magnetic fusion research program required a simulant for liquid lithium. The simulant choices were narrowed to liquid gallium and galinstan (Ga-In-Sn) alloy. Safety information on liquid gallium and galinstan were compiled, and the choice was made to use galinstan. A laboratory safety walkthrough was performed in the fall of 2002 to support the galinstan experiment. The experiment has been operating successfully since early 2002

  6. Lattice Dynamics of Gallium Phosphide

    International Nuclear Information System (INIS)

    Yarnell, J.L.; Warren, J.L.; Wenzel, R.G.; Dean, P.J.

    1968-01-01

    Dispersion curves for phonons propagating in the [100], [110], and [111] directions in gallium phosphide have been measured using a triple-axis neutron diffraction spectrometer operating in the constant-Q mode. The sample was a pseudo-single crystal which was prepared by gluing together 36 single crystal plates of gallium phosphide 1 to 2.5 cm in diameter and ∼0.07 cm thick. The plates were grown epitaxially on substrates of gallium arsenide or gallium phosphide, and aligned individually by neutron diffraction. Rocking curves for eight reflections symmetrically distributed in the plane of the experiment had full widths at half maximum in the range 0.52° - 0.58° and were approximately Gaussian in shape. Gallium phosphide crystallizes in the zinc blende structure. A group theoretic analysis of the lattice dynamics of this structure and a shell model fit to the measured dispersion curves are presented. Various optical properties of gallium phosphide are discussed in terms of the phonon dispersion curves. In particular, the phonons which assist indirect electronic transitions are identified as those at the zone boundary in the [100] direction (symmetry point X) in agreement with theoretical and experimental indications that the extrema of the conduction and valence bands are at X and Γ (center of the zone), respectively. The LO branches lie above the TO branches throughout the Brillouin zone in contradiction to the predictions of Keyes and Mitra. The shell model fit indicates that the charge on the gallium atom is negative. (author)

  7. Collector for recovering gallium from weapons plutonium

    International Nuclear Information System (INIS)

    Philip, C.V.; Anthony, R.G.; Chokkaram, S.

    1998-09-01

    Currently, the separation of gallium from weapons plutonium involves the use of aqueous processing using either solvent extraction of ion exchange. However, this process generates significant quantities of liquid radioactive wastes. A Thermally Induced Gallium Removal process, or TIGR, developed by researchers at Los Alamos National Laboratories, is a simpler alternative to aqueous processing. This research examined this process, and the behavior of gallium suboxide, a vapor that is swept away by passing hydrogen/argon over gallium trioxide/plutonium oxide heated at 1100 C during the TIGR process. Through experimental procedures, efforts were made to prevent the deposition of corrosive gallium onto furnace and vent surfaces. Experimental procedures included three options for gallium removal and collection: (1) collection of gallium suboxide through use of a cold finger; (2) collection by in situ air oxidation; and (3) collection of gallium on copper. Results conclude all three collection mechanisms are feasible. In addition, gallium trioxide exists in three crystalline forms, and each form was encountered during each experiment, and that each form will have a different reactivity

  8. Critical fields and growth rates of the Tayler instability as probed by a columnar gallium experiment

    OpenAIRE

    Ruediger, Guenther; Gellert, Marcus; Schultz, Manfred; Strassmeier, Klaus G.; Stefani, Frank; Gundrum, Thomas; Seilmayer, Martin; Gerbeth, Gunter

    2012-01-01

    Many astrophysical phenomena (such as the slow rotation of neutron stars or the rigid rotation of the solar core) can be explained by the action of the Tayler instability of toroidal magnetic fields in the radiative zones of stars. In order to place the theory of this instability on a safe fundament it has been realized in a laboratory experiment measuring the critical field strength, the growth rates as well as the shape of the supercritical modes. A strong electrical current flows through a...

  9. Prospects of the Syria conflict’s settlement in the context of the exasperation of Russian-American relations

    Directory of Open Access Journals (Sweden)

    O. S. Vonsovych

    2017-01-01

    Full Text Available The prospects of the Syria conflict’s settlement in the context of exasperation of Russian-American relations have been investigated. Nowadays this conflict is one of the largest centers of danger in the world. Moreover, after the intervention of Russian Federation and United States of America in the conflict, it gained even greater complexity, contradictions and urgency. We should say that after analyzing the positions of participants of the conflict, it is clear that the rapid resolution of the situation shouldn’t be expected. Such factors as differences in views and positions, antagonistic mood, uncompromising, aggressive behavior, the prevalence of power factor, terrorist activity and others do not allow improving the performance reconciliation of the parties’ process. Important thing is that exasperation of Russian-American relations is one of the key negative external factors, which makes it impossible to establish meaningful strategic dialogue between the conflicting parties. The process of further settlement will depend on how quickly Russian and American parties will find understanding regarding key issues of the conflict. Not less important is the conflict settlement processes. Now this process seems to be very complicated. Divergence of interests and views of direct participants and key «players» Russia and the United States do not allow to speak about the presence of compromise and constructive dialogue. If they are not achieved soon, it can lead to unpredictable consequences, such as the expansion of «geography» of the conflict or its transfer to other areas. We should pay attention to the fact that further exasperation of Russian-American relations may cause open military confrontation between this two countries about which people have recently started talking more often. This confrontation complicates not only the progress of the conflict, but also creates some additional problems that affect negatively the dynamic of

  10. Joint Russian-American hydrogeological-geochemical studies of the Karachai-Mishelyak system, South Urals, Russia

    International Nuclear Information System (INIS)

    Drozhko, E.G.; Glagolenko, Y.U.; Mokrov, Y.G.; Postovalova, G.A.; Samsonova, L.M.; Glagolev, A.V.; Ter-Saakian, S.A.; Glinsky, M.L.; Vasil'kova, N.A.; Skokov, A.V.; Wollenberg, H.A.; Tsan, C.F.; Frangos, W.; Solbau, R.D.; Stevenson, K.A.

    1997-01-01

    In September 1994, a Russian-American team conducted hydrogeological, geochemical, geophysical, and radiometric measurements in the teritory of the Mayak Production Association, Russia. The primary purpose of these operations was to examine the frontal area of a radioelement- and nitrate-laden groundwater plume moving from the disposal site, Lake Karachai, toward the Mishelyak River. Activities encompassed (1) isolation of hydrologic intervgals in two wells and production of water from these intervals, to comapre isolated versus open-well sampling methods and to determine hydraulic transmissivities of the aquifer(s); (2) surface and soil-water sampling, accompanying radiometric measurements and subsequent chemical analyses; and (3) electrical resistivity profiling in areas of expected contrasting resistivity. Preliminary results indicate that (1) 60 Co, 137 Cs, and 90 Sr are present in small concentrations (∝0.1% of permissible levels) in water of the Mishelyak River; (2) analyses of water samples collected by a downhole sampler and of water produced from packed-off intevals agree within limits of laboratory accuracy, attesting to the efficacy of the sampling methods presently used by the Russian workers; (3) considerable differences in contaminant concentrations exist between nearby wells, supporting the concept that the plume from Lake Karachai toward the Mishelyak River is controlled by steeply dipping fractures and shear zones; and (4) strong contrasts occur between the electrical resistivities of soil and bedrock. (orig./SR)

  11. A joint Russian-American field test at the Chelyabinsk-65 (Mayak) Site: Test description and preliminary results

    International Nuclear Information System (INIS)

    Wollenberg, H.; Tsang, C.F.; Frangos, W.

    1995-05-01

    In September 1994, a Russian-American team conducted hydrogeological, geochemical, geophysical, and radiometric measurements in the territory of the Mayak Production Association. The primary purpose of these operations was to examine the groundwater plume moving from Lake Karachai toward the river. Activities encompassed isolation of hydrologic intervals in two wells and production of water from these intervals, to compare isolated versus open-well sampling methods; surface and soil-water sampling, accompanying radiometric measurements and subsequent chemical analyses; and electrical resistivity profiling in areas of expected contrasting resistivity. Preliminary results indicate that (1) 60 Co and 137 Cs are present in small concentrations in water of the Mishelyak River, (2) analyses of water samples collected by a downhole sampler and of water produced from packed-off intervals agree within limits of laboratory accuracy, attesting to the efficacy of the sampling methods presently used by the Russian workers; and (3) strong contrasts occur between the electrical resistivities of soil and bedrock. Further collaborative work is strongly recommended, and should include more detailed isolation of intervals in wells by multi-packer installations, to better determine the geochemical and hydrological characteristics of the Karachai-Mishelyak system; deployment of a broader soil-water and soil sampling array; a more detailed examination of the distribution and concentration of radionuclides by high-resolution field gamma spectrometry; and a detailing of the area's electrical resistivity setting, using a mobile electromagnetic measurement system

  12. Project proposals on the creation of Russian-American joint enterprise for investigation, development and manufacture of power plants on the basis of solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Smotrov, N.V.; Kleschev, Yu.N.

    1996-04-01

    This paper describes a proposal for a joint Russian-American enterprise for performing scientific investigations, development, and manufacture of fuel cell power plants on the basis of the solid oxide fuel cell. RASOFCo. Russian-American Solid Oxide Fuel Cells Company. RASOFCo will provide the series output of the electrochemical generator (ECG) of 1kW power, then of 5kW and 10kW as well as the development and the output of 10kW power plant with the subsequent output of a power plant of greater power. An ECG based on solid oxide fuel cells uses methane as a fuel. Predicted technical characteristics, market analysis, assessment of potential demands for power plants of low power for Tyumentransgas, participants of the joint enterprise and their founding contributions, strategy for manufacture and financing, and management of RASOFCo are discussed.

  13. Demonstrating appropriate silviculture for sustainable forestry in central Siberia: a Russian - American partnership

    Science.gov (United States)

    J. C. Brissette; S. T. Eubanks; A. J. R. Gillespie; R. J. Lasko; A. V. Rykoff

    1997-01-01

    A joint Northeastern Forest Experiment Station - Eastern Region team is working with Russian counterparts on a Forests for the Future Initiative in the Krasnoyarsk region of central Siberia. Russian team members include scientists from the Sukachev Institute of the Russian Academy of Sciences, managers from a number of units of the Federal Forest Service of Russia, and...

  14. Measurement of the solar neutrino capture rate with gallium metal, part III

    International Nuclear Information System (INIS)

    Elliott, Steven Ray

    2008-01-01

    The Russian-American experiment SAGE began to measure the solar neutrino capture rate with a target of gallium metal in December 1989. Measurements have continued with only a few brief interruptions since that time. In this article we present the experimental improvements in SAGE since its last published data summary in December 2001. Assuming the solar neutrino production rate was constant during the period of data collection, combined analysis of 168 extractions through December 2007 gives a capture rate of solar neutrinos with energy more than 233 keY of 65.4 +3.1 3.0 (stat) +2.6 -2.8 (syst) SNU. The weighted average of the results of all three Ga solar neUlrino experiments, SAGE, Gallex, and GNO, is now 66.1 ± 3.1 SNU, where statistical and systematic uncertainties have been combined in quadrature. During the recent period of data collection a new test of SAGE was made with a reactor-produced 37 Ar neutrino source. The ratio of observed to calculated rates in this experiment, combined with the measured rates in the three prior 51 Cr neutrino-source experiments with Ga, is 0.88 ± 0.05. A probable explanation for this low result is that the cross section for neutrino capture by the two lowest-lying excited states in 71 Ge has been overestimated. If we assume these cross sections are zero, then the standard solar model including neutrino oscillations predicts a total capture rate in Ga in the range of 63--67 SNU with an uncertainly of about 5%, in good agreement with experiment. We derive the current value of the pp neutrino flux produced in the Sun to be φ · pp = (6.1 ± 0.8) x 10 10 /(cm 2 s), which agrees well with the flux predicted by the standard solar model. Finally, we make several tests and show that the data are consistent with the assumption that the solar neutrino production rate is constant in time.

  15. Nuclear microprobe imaging of gallium nitrate in cancer cells

    Science.gov (United States)

    Ortega, Richard; Suda, Asami; Devès, Guillaume

    2003-09-01

    Gallium nitrate is used in clinical oncology as treatment for hypercalcemia and for cancer that has spread to the bone. Its mechanism of antitumor action has not been fully elucidated yet. The knowledge of the intracellular distribution of anticancer drugs is of particular interest in oncology to better understand their cellular pharmacology. In addition, most metal-based anticancer compounds interact with endogenous trace elements in cells, altering their metabolism. The purpose of this experiment was to examine, by use of nuclear microprobe analysis, the cellular distribution of gallium and endogenous trace elements within cancer cells exposed to gallium nitrate. In a majority of cellular analyses, gallium was found homogeneously distributed in cells following the distribution of carbon. In a smaller number of cells, however, gallium appeared concentrated together with P, Ca and Fe within round structures of about 2-5 μm diameter located in the perinuclear region. These intracellular structures are typical of lysosomial material.

  16. Nuclear microprobe imaging of gallium nitrate in cancer cells

    International Nuclear Information System (INIS)

    Ortega, Richard; Suda, Asami; Deves, Guillaume

    2003-01-01

    Gallium nitrate is used in clinical oncology as treatment for hypercalcemia and for cancer that has spread to the bone. Its mechanism of antitumor action has not been fully elucidated yet. The knowledge of the intracellular distribution of anticancer drugs is of particular interest in oncology to better understand their cellular pharmacology. In addition, most metal-based anticancer compounds interact with endogenous trace elements in cells, altering their metabolism. The purpose of this experiment was to examine, by use of nuclear microprobe analysis, the cellular distribution of gallium and endogenous trace elements within cancer cells exposed to gallium nitrate. In a majority of cellular analyses, gallium was found homogeneously distributed in cells following the distribution of carbon. In a smaller number of cells, however, gallium appeared concentrated together with P, Ca and Fe within round structures of about 2-5 μm diameter located in the perinuclear region. These intracellular structures are typical of lysosomial material

  17. Gallium scintigraphy in AIDS

    International Nuclear Information System (INIS)

    Van der Wall, Hans; Provan, I.; Murray, C.; Dwyer, M.; Jones, P.D.

    1990-01-01

    Gallium-67 scanning, indicated either for the elucidation of symptoms or for the assessment of appropriate therapy, was performed in 56 AIDS patients who underwent a total of 77 scans from 1986 to 1988. The age range of the patients was 13-66 years with an average age of 39 years. The majority of patients (95%) were male homosexuals. Gallium scanning has been applied to a wide spectrum of malignancies and to the detection of occult infections. Several mechanisms of uptake have been postulated for the localization of gallium. In general, gallium-67 acts as an analogue of the ferric ion, binding to transferrin soon after intravenous injection. It is believed that it is bound to transferrin receptors on the surface of tumour cells with subsequent intracellular transport. In infection, the association is probably with lactoferrin elaborated by polymorphonuclear cells and siderophores elaborated by bacteria. Gallium-67 is normally distributed to bone and bone marrow, liver, spleen, breast and bowel. In particular, the concentration in the ascending and transverse colon necessitates adequate bowel preparation. Lacrimal, nasopharyngeal and genital activity may also be seen. 11 refs., 2 tabs., 6 figs

  18. Proportional counter response calculations for gallium solar neutrino detectors

    International Nuclear Information System (INIS)

    Kouzes, R.T.; Reynolds, D.

    1989-01-01

    Gallium bases solar neutrino detectors are sensitive to the primary pp reaction in the sun. Two experiments using gallium, SAGE in the Soviet Union and GALLEX in Europe, are under construction and will produce data by 1989. The radioactive /sup 71/Ge produced by neutrinos interacting with the gallium detector material, is chemically extracted and counted in miniature proportional counters. A number of calculations have been carried out to simulate the response of these counters to the decay of /sup 71/Ge and to background events

  19. Gallium and copper radiopharmaceutical chemistry

    International Nuclear Information System (INIS)

    Green, M.A.

    1991-01-01

    Gallium and copper radionuclides have a long history of use in nuclear medicine. Table 1 presents the nuclear properties of several gallium and copper isotopes that either are used in the routine practice of clinical nuclear medicine or exhibit particular characteristics that might make them useful in diagnostic or therapeutic medicine. This paper will provide some historic perspective along with an overview of some current research directions in gallium and copper radiopharmaceutical chemistry. A more extensive review of gallium radiopharmaceutical chemistry has recently appeared and can be consulted for a more in-depth treatment of this topic

  20. Gallium--A smart metal

    Science.gov (United States)

    Foley, Nora; Jaskula, Brian W.

    2013-01-01

    Gallium is a soft, silvery metallic element with an atomic number of 31 and the chemical symbol Ga. The French chemist Paul-Emile Lecoq de Boisbaudran discovered gallium in sphalerite (a zinc-sulfide mineral) in 1875 using spectroscopy. He named the element "gallia" after his native land of France (formerly Gaul; in Latin, Gallia). The existence of gallium had been predicted in 1871 by Dmitri Mendeleev, the Russian chemist who published the first periodic table of the elements. Mendeleev noted a gap in his table and named the missing element "eka-aluminum" because he determined that its location was one place away from aluminum in the table. Mendeleev thought that the missing element (gallium) would be very much like aluminum in its chemical properties, and he was right. Solid gallium has a low melting temperature (~29 degrees Celsius, or °C) and an unusually high boiling point (~2,204 °C). Because of these properties, the earliest uses of gallium were in high-temperature thermometers and in designing metal alloys that melt easily. The development of a gallium-based direct band-gap semiconductor in the 1960s led to what is now one of the most well-known applications for gallium-based products--the manufacture of smartphones and data-centric networks.

  1. Clinical applications of Gallium-68

    International Nuclear Information System (INIS)

    Banerjee, Sangeeta Ray; Pomper, Martin G.

    2013-01-01

    Gallium-68 is a positron-emitting radioisotope that is produced from a 68 Ge/ 68 Ga generator. As such it is conveniently used, decoupling radiopharmacies from the need for a cyclotron on site. Gallium-68-labeled peptides have been recognized as a new class of radiopharmaceuticals showing fast target localization and blood clearance. 68 Ga-DOTATOC, 8 Ga-DOTATATE, 68 Ga-DOTANOC, are the most prominent radiopharmaceuticals currently in use for imaging and differentiating lesions of various somatostatin receptor subtypes, overexpressed in many neuroendocrine tumors. There has been a tremendous increase in the number of clinical studies with 68 Ga over the past few years around the world, including within the United States. An estimated ∼10,000 scans are being performed yearly in Europe at about 100 centers utilizing 68 Ga-labeled somatostatin analogs within clinical trials. Two academic sites within the US have also begun to undertake human studies. This review will focus on the clinical experience of selected, well-established and recently applied 68 Ga-labeled imaging agents used in nuclear medicine. - Highlights: ► A summary of the emerging clinical uses of 68 Ga-based radiopharmaceuticals is provided. ► 68 Ga-PET may prove as or more clinically robust than the corresponding 18 F-labeled agents. ► 68 Ga-radiopeptides were studied for targeting of somatostatin receptors subtypes. ► 68 Ga-DOTATOC, 68 Ga-DOTATATE, 68 Ga-DOTANOC, are currently in clinical trials

  2. Electrospun Gallium Nitride Nanofibers

    International Nuclear Information System (INIS)

    Melendez, Anamaris; Morales, Kristle; Ramos, Idalia; Campo, Eva; Santiago, Jorge J.

    2009-01-01

    The high thermal conductivity and wide bandgap of gallium nitride (GaN) are desirable characteristics in optoelectronics and sensing applications. In comparison to thin films and powders, in the nanofiber morphology the sensitivity of GaN is expected to increase as the exposed area (proportional to the length) increases. In this work we present electrospinning as a novel technique in the fabrication of GaN nanofibers. Electrospinning, invented in the 1930s, is a simple, inexpensive, and rapid technique to produce microscopically long ultrafine fibers. GaN nanofibers are produced using gallium nitrate and dimethyl-acetamide as precursors. After electrospinning, thermal decomposition under an inert atmosphere is used to pyrolyze the polymer. To complete the preparation, the nanofibers are sintered in a tube furnace under a NH 3 flow. Both scanning electron microscopy and profilometry show that the process produces continuous and uniform fibers with diameters ranging from 20 to a few hundred nanometers, and lengths of up to a few centimeters. X-ray diffraction (XRD) analysis shows the development of GaN nanofibers with hexagonal wurtzite structure. Future work includes additional characterization using transmission electron microscopy and XRD to understand the role of precursors and nitridation in nanofiber synthesis, and the use of single nanofibers for the construction of optical and gas sensing devices.

  3. Measurement of the solar neutrino capture rate with gallium metal. III. Results for the 2002-2007 data-taking period

    International Nuclear Information System (INIS)

    Abdurashitov, J. N.; Gavrin, V. N.; Gorbachev, V. V.; Gurkina, P. P.; Ibragimova, T. V.; Kalikhov, A. V.; Khairnasov, N. G.; Knodel, T. V.; Mirmov, I. N.; Shikhin, A. A.; Veretenkin, E. P.; Yants, V. E.; Zatsepin, G. T.; Bowles, T. J.; Elliott, S. R.; Teasdale, W. A.; Nico, J. S.; Cleveland, B. T.; Wilkerson, J. F.

    2009-01-01

    The Russian-American experiment SAGE began to measure the solar neutrino capture rate with a target of gallium metal in December 1989. Measurements have continued with only a few brief interruptions since that time. In this article we present the experimental improvements in SAGE since its last published data summary in December 2001. Assuming the solar neutrino production rate was constant during the period of data collection, combined analysis of 168 extractions through December 2007 gives a capture rate of solar neutrinos with energy more than 233 keV of 65.4 -3.0 +3.1 (stat) -2.8 +2.6 (syst) SNU. The weighted average of the results of all three Ga solar neutrino experiments, SAGE, Gallex, and GNO, is now 66.1±3.1 SNU, where statistical and systematic uncertainties have been combined in quadrature. During the recent period of data collection a new test of SAGE was made with a reactor-produced 37 Ar neutrino source. The ratio of observed to calculated rates in this experiment, combined with the measured rates in the three prior 51 Cr neutrino-source experiments with Ga, is 0.87±0.05. A probable explanation for this low result is that the cross section for neutrino capture by the two lowest-lying excited states in 71 Ge has been overestimated. If we assume these cross sections are zero, then the standard solar model including neutrino oscillations predicts a total capture rate in Ga in the range of 63 SNU to 66 SNU with an uncertainty of about 4%, in good agreement with experiment. We derive the current value of the neutrino flux produced in the Sun by the proton-proton fusion reaction to be φ pp · =(6.0±0.8)x10 10 /(cm 2 s), which agrees well with the pp flux predicted by the standard solar model. Finally, we make several tests and show that the data are consistent with the assumption that the solar neutrino production rate is constant in time.

  4. Gallium interstitial contributions to diffusion in gallium arsenide

    Science.gov (United States)

    Schick, Joseph T.; Morgan, Caroline G.

    2011-09-01

    A new diffusion path is identified for gallium interstitials, which involves lower barriers than the barriers for previously identified diffusion paths [K. Levasseur-Smith and N. Mousseau, J. Appl. Phys. 103, 113502 (2008), P. A. Schultz and O. A. von Lilienfeld, Modelling and Simulation in Materials Science and Engineering 17, 084007 (2009)] for the charge states which dominate diffusion over most of the available range of Fermi energies. This path passes through the ⟨110⟩ gallium-gallium split interstitial configuration, and has a particularly low diffusion barrier of 0.35 eV for diffusion in the neutral charge state. As a part of this work, the character of the charge states for the gallium interstitials which are most important for diffusion is investigated, and it is shown that the last electron bound to the neutral interstitial occupies a shallow hydrogenic bound state composed of conduction band states for the hexagonal interstitial and both tetrahedral interstitials. How to properly account for the contributions of such interstitials is discussed for density-functional calculations with a k-point mesh not including the conduction band edge point. Diffusion barriers for gallium interstitials are calculated in all the charge states which can be important for a Fermi level anywhere in the gap, q = 0, +1, +2, and +3, for diffusion via the ⟨110⟩ gallium-gallium split interstitial configuration and via the hexagonal interstitial configuration. The lowest activation enthalpies over most of the available range of Fermi energies are found to correspond to diffusion in the neutral or singly positive state via the ⟨110⟩ gallium-gallium split interstitial configuration. It is shown that several different charge states and diffusion paths contribute significantly for Fermi levels within 0.2 eV above the valence band edge, which may help to explain some of the difficulties [H. Bracht and S. Brotzmann, Phys. Rev. B 71, 115216 (2005)] which have been

  5. Prospects for recovering gallium from extracted coal

    Energy Technology Data Exchange (ETDEWEB)

    Ratynskiy, V M; Reznik, A M; Zekel, L A; Zharov, Yu N

    1979-01-01

    The authors conducted research in order to establish the physical-chemical mechanisms governing the behavior of rare and dispersed elements within the thermal treatment processes used to treat coal and enrichment waste. New means are proposed for obtaining concentrations of gallium. These methods are under consideration primarily for the isolation of gallium as a by-product during the production of aggloporite from coal waste. The authors examine in detail the results of research dealing with the transfer of gallium compounds in a solution, the extraction of gallium from solutions, the separation of impurities from gallium, and the isolation of gallium from extract. Utilizing research results, the authors determine the expenditure coefficient and costs for additives used to extract gallium from waste by-products. The realization of this gallium extraction process from those products having the best prospects for gallium content resulted in economic savings.

  6. Development of Regulatory Documents for Creation (Upgrade) of Physical Protection Systems under the Russian/American MPC and A Program

    International Nuclear Information System (INIS)

    Izmaylov, Alexandr V.; Babkin, Vladimir; Kurov, Valeriy; Piskarev, Alexander; O'Brien, Patricia E.; Wright, Troy L.; Schlegel, Stephen C.; Hazel, Michael J.; Miller, Daniel R.; Tuttle, John D.; Kovchegin, Dmitry

    2009-01-01

    The development of new or the upgrade of existing physical protection systems (PPS) for nuclear facilities involves a multi-step and multidimensional process. The process consists of conceptual design, design, and commissioning stages. The activities associated with each of these stages are governed by Russian government and agency regulations. To ensure a uniform approach to development or upgrading of PPS at Russian nuclear facilities, the development of a range of regulatory and methodological documents is necessary. Some issues of PPS development are covered by the regulatory documents developed by Rosatom, as well as other Russian agencies with nuclear facilities under their control. This regulatory development has been accomplished as part of the U.S.-Russian MPC and A cooperation or independently by the Russian Federation. While regulatory coverage is extensive, there are a number of issues such as vulnerability analysis, effectiveness assessment, upgrading PPS, and protection of information systems for PPS that require additional regulations be developed. This paper reports on the status of regulatory coverage for PPS development or upgrade, and outlines a new approach to regulatory document development. It describes the evolutionary process of regulatory development through experience gained in the design, development and implementation of PPS as well as experience gained through the cooperative efforts of Russian and U.S. experts involved the development of MPC and A regulations.

  7. ASSESSMENT OF GALLIUM OXIDE TECHNOLOGY

    Science.gov (United States)

    2017-08-01

    AFRL-RY-WP-TR-2017-0167 ASSESSMENT OF GALLIUM OXIDE TECHNOLOGY Burhan Bayraktaroglu Devices for Sensing Branch Aerospace...TITLE AND SUBTITLE ASSESSMENT OF GALLIUM OXIDE TECHNOLOGY 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER N/A 6...report summarizes the current status of the Ga2O3 technology based on published results on theoretical electronic structure, materials growth, and

  8. Gallium and imaging studies

    International Nuclear Information System (INIS)

    Vogel, H.C.

    1982-01-01

    The indications for the use of 67 Gallium imaging studies of the lungs are discussed. In spite of localization of 67 Ga in a large variety of neoplastic and inflammatory tissues, there is only limited application of the lung study in the differential diagnosis of pulmonary diseases. The chest radiograph will continue to be the principal tool for evaluation of pulmonary diseases. The 67 Ga-citrate scan serves as a study complementary to the chest radiograph, as it indicates the localization, extent and degree of activity of lung disease with greater accuracy than radiography. Gallium-67 scanning may be used in the evaluation of patients with lymphoreticular neoplasms, especially Hodgkin-disease and malignant lymphoma both during initial staging and in evaluation of the response to therapy. The 67 Ga-citrate scan is useful in the pre-operative evaluation of patients with lung cancer. Hilar and mediastinal lymphadenopathy are accurately revealed. The lung study is non-invasive and complementary to mediastinoscopy by showing from which glands a biopsy might be taken. Unsuspected extrathoracic secondaries may be shown up, as well as pulmonary metastases from malignancies elsewhere, although the metastases must be at least 1,5 cm in size. The 67 Ga lung scan is valuable in the evaluation of pulmonary infiltrates of suspicious infective etiology, the differentiation between pulmonary infection and pneumonia in selected cases, follow-up of sarcoid patients on corticosteroid therapy, evaluation of inflammatory activity of idiopathic pulmonary fibrosis and the early detection of neo-plastic or inflammatory diseases before the chest radiograph reveals abnormality, e.g. in diffuse carcinomatosis or Pneumocystis carinii-infection. The sensitivity of tumors to radiation or chemotherapy may be shown

  9. Structural variations in nanosized confined gallium

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Min Kai [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China); Tien Cheng [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China)] [Center for Micro/Nano Science of Technology, National Cheng Kung University, Tainan 70101, Taiwan, ROC (China); Charnaya, E.V., E-mail: charnaya@live.co [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China)] [Institute of Physics, St. Petersburg State University, St. Petersburg, Petrodvorets 198504 (Russian Federation); Sheu, Hwo-Shuenn [National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China); Kumzerov, Yu.A. [A.F. Ioffe Physico-Technical Institute RAS, St. Petersburg, 194021 (Russian Federation)

    2010-03-29

    The complex crystalline structure of gallium under nanoconfinement was revealed by synchrotron radiation x-ray powder diffraction. Nanoconfinement was shown to stabilize delta-Ga which is metastable in bulk. Two new gallium phases named iota- and kappa-Ga were found upon cooling below room temperature. These crystalline modifications were stable and coexisted with known gallium phases. Correlations between confined gallium particle shapes and emergence of particular crystalline phases were observed. Melting and freezing temperatures for different gallium phases were obtained. Remarkable supercooling of liquid gallium was seen in 3.5 nm pores.

  10. Surface Passivation of CIGS Solar Cells Using Gallium Oxide

    KAUST Repository

    Garud, Siddhartha

    2018-02-27

    This work proposes gallium oxide grown by plasma-enhanced atomic layer deposition, as a surface passivation material at the CdS buffer interface of Cu(In,Ga)Se2 (CIGS) solar cells. In preliminary experiments, a metal-insulator-semiconductor (MIS) structure is used to compare aluminium oxide, gallium oxide, and hafnium oxide as passivation layers at the CIGS-CdS interface. The findings suggest that gallium oxide on CIGS may show a density of positive charges and qualitatively, the least interface trap density. Subsequent solar cell results with an estimated 0.5 nm passivation layer show an substantial absolute improvement of 56 mV in open-circuit voltage (VOC), 1 mA cm−2 in short-circuit current density (JSC), and 2.6% in overall efficiency as compared to a reference (with the reference showing 8.5% under AM 1.5G).

  11. Optical Properties of Gallium-Doped Zinc Oxide—A Low-Loss Plasmonic Material: First-Principles Theory and Experiment

    Directory of Open Access Journals (Sweden)

    Jongbum Kim

    2013-12-01

    Full Text Available Searching for better materials for plasmonic and metamaterial applications is an inverse design problem where theoretical studies are necessary. Using basic models of impurity doping in semiconductors, transparent conducting oxides (TCOs are identified as low-loss plasmonic materials in the near-infrared wavelength range. A more sophisticated theoretical study would help not only to improve the properties of TCOs but also to design further lower-loss materials. In this study, optical functions of one such TCO, gallium-doped zinc oxide (GZO, are studied both experimentally and by first-principles density-functional calculations. Pulsed-laser-deposited GZO films are studied by the x-ray diffraction and generalized spectroscopic ellipsometry. Theoretical studies are performed by the total-energy-minimization method for the equilibrium atomic structure of GZO and random phase approximation with the quasiparticle gap correction. Plasma excitation effects are also included for optical functions. This study identifies mechanisms other than doping, such as alloying effects, that significantly influence the optical properties of GZO films. It also indicates that ultraheavy Ga doping of ZnO results in a new alloy material, rather than just degenerately doped ZnO. This work is the first step to achieve a fundamental understanding of the connection between material, structural, and optical properties of highly doped TCOs to tailor those materials for various plasmonic applications.

  12. Superconductivity and structure of gallium under nanoconfinement

    Energy Technology Data Exchange (ETDEWEB)

    Charnaya, E V; Tien, Cheng; Lee, Min Kai [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China); Kumzerov, Yu A [A F Ioffe Physico-Technical Institute RAS, St Petersburg, 194021 (Russian Federation)

    2009-11-11

    Superconductivity and crystalline structure were studied for two nanocomposites consisting of gallium loaded porous glasses with different pore sizes. The superconducting transition temperatures were found to differ from those in known bulk gallium modifications. The transition temperatures 7.1 and 6.7 K were ascribed to two new confined gallium structures, iota- and kappa-Ga, observed by synchrotron radiation x-ray powder diffraction. The evolution of superconductivity on decreasing the pore filling with gallium was also studied.

  13. Hydrogen inventory in gallium

    International Nuclear Information System (INIS)

    Mazayev, S.N.; Prokofiev, Yu.G.

    1994-01-01

    Investigations of hydrogen inventory in gallium (99.9%) were carried out after saturation both from molecular phase and from glow discharge plasma at room temperature, 370 and 520 K. Saturation took place during 3000 s under hydrogen pressure of 20 Pa, and ion flux was about 1x10 15 ions/cm 2 s with an energy about 400 eV during discharge. Hydrogen concentration in Ga at room temperature and that for 370 K by the saturation from gaseous phase was (2-3)x10 14 cm -3 Pa -1/2 . Hydrogen concentration at temperature 520 K increased by five times. Inventory at room temperature for irradiation from discharge was 7x10 16 cm -3 at the dose about 3x10 18 ions/cm 2 . It was more than inventory at temperature 520 K by four times and more than maximum inventory from gaseous phase at 520 K by a factor of 10. Inventory increased when temperature decreased. Diffusion coefficient D=0.003 exp(-2300/RT) cm 2 /s, was estimated from temperature dependence. ((orig.))

  14. Gallium scintigraphy in Hansen's disease

    International Nuclear Information System (INIS)

    Braga, F.J.H.N.; Sao Paulo Univ., SP; Araejo, E.B.; Camargo, E.E.; Tedesco-Marchesi, L.C.M.; Rivitti, M.C.M.; Bouladour, H.; Galle, P.

    1991-01-01

    Gallium 67 imaging was used in 12 patients with documented Hansen's disease undergoing treatment or not in an attempt to determine the pattern of the disease. Diagnosis was confirmed by histopathology in all patients. The Mitsuda reaction was seen in all patients. Specific nuclear studies were performed when needed to evaluate particular organs better. Gallium 67 images show homogeneous, diffuse and moderate accumulation over the entire skin surface (except for the face) of untreated patients with multibacillary disease. The face skin in these cases presented homogeneous, diffuse but very marked uptake of gallium. Internal organ involvement was variable. There was a very good correlation among clinical, scintigraphical, immunological and histopathological data. The pattern of the body skin ('skin outlining') and face skin ('beard distribution') may be distinct for untreated patients with multibacillary leprosy. (orig.)

  15. Medical Applications and Toxicities of Gallium Compounds

    Directory of Open Access Journals (Sweden)

    Christopher R. Chitambar

    2010-05-01

    Full Text Available Over the past two to three decades, gallium compounds have gained importance in the fields of medicine and electronics. In clinical medicine, radioactive gallium and stable gallium nitrate are used as diagnostic and therapeutic agents in cancer and disorders of calcium and bone metabolism. In addition, gallium compounds have displayed anti-inflammatory and immunosuppressive activity in animal models of human disease while more recent studies have shown that gallium compounds may function as antimicrobial agents against certain pathogens. In a totally different realm, the chemical properties of gallium arsenide have led to its use in the semiconductor industry. Gallium compounds, whether used medically or in the electronics field, have toxicities. Patients receiving gallium nitrate for the treatment of various diseases may benefit from such therapy, but knowledge of the therapeutic index of this drug is necessary to avoid clinical toxicities. Animals exposed to gallium arsenide display toxicities in certain organ systems suggesting that environmental risks may exist for individuals exposed to this compound in the workplace. Although the arsenic moiety of gallium arsenide appears to be mainly responsible for its pulmonary toxicity, gallium may contribute to some of the detrimental effects in other organs. The use of older and newer gallium compounds in clinical medicine may be advanced by a better understanding of their mechanisms of action, drug resistance, pharmacology, and side-effects. This review will discuss the medical applications of gallium and its mechanisms of action, the newer gallium compounds and future directions for development, and the toxicities of gallium compounds in current use.

  16. Toxicity of indium arsenide, gallium arsenide, and aluminium gallium arsenide

    International Nuclear Information System (INIS)

    Tanaka, Akiyo

    2004-01-01

    Gallium arsenide (GaAs), indium arsenide (InAs), and aluminium gallium arsenide (AlGaAs) are semiconductor applications. Although the increased use of these materials has raised concerns about occupational exposure to them, there is little information regarding the adverse health effects to workers arising from exposure to these particles. However, available data indicate these semiconductor materials can be toxic in animals. Although acute and chronic toxicity of the lung, reproductive organs, and kidney are associated with exposure to these semiconductor materials, in particular, chronic toxicity should pay much attention owing to low solubility of these materials. Between InAs, GaAs, and AlGaAs, InAs was the most toxic material to the lung followed by GaAs and AlGaAs when given intratracheally. This was probably due to difference in the toxicity of the counter-element of arsenic in semiconductor materials, such as indium, gallium, or aluminium, and not arsenic itself. It appeared that indium, gallium, or aluminium was toxic when released from the particles, though the physical character of the particles also contributes to toxic effect. Although there is no evidence of the carcinogenicity of InAs or AlGaAs, GaAs and InP, which are semiconductor materials, showed the clear evidence of carcinogenic potential. It is necessary to pay much greater attention to the human exposure of semiconductor materials

  17. Potential effects of gallium on cladding materials

    International Nuclear Information System (INIS)

    Wilson, D.F.; Beahm, E.C.; Besmann, T.M.; DeVan, J.H.; DiStefano, J.R.; Gat, U.; Greene, S.R.; Rittenhouse, P.L.; Worley, B.A.

    1997-10-01

    This paper identifies and examines issues concerning the incorporation of gallium in weapons derived plutonium in light water reactor (LWR) MOX fuels. Particular attention is given to the more likely effects of the gallium on the behavior of the cladding material. The chemistry of weapons grade (WG) MOX, including possible consequences of gallium within plutonium agglomerates, was assessed. Based on the calculated oxidation potentials of MOX fuel, the effect that gallium may have on reactions involving fission products and possible impact on cladding performance were postulated. Gallium transport mechanisms are discussed. With an understanding of oxidation potentials and assumptions of mechanisms for gallium transport, possible effects of gallium on corrosion of cladding were evaluated. Potential and unresolved issues and suggested research and development (R and D) required to provide missing information are presented

  18. The Effect of Gallium Nitrate on Arresting Blood Flow from a Wound

    Directory of Open Access Journals (Sweden)

    Paul H. Goodley

    2011-01-01

    Full Text Available A novel application of gallium nitrate, hitherto unreported, in reducing bleeding time from an open wound is presented. Experiments performed using simple punctures in the forearm demonstrated a very substantial reduction in bleeding time when a solution of gallium nitrate was applied relative to a control. This outcome was shown to be unaffected by the anticoagulant properties of warfarin. The mechanism for such action of gallium nitrate is unknown and merits further investigation, as do the possibilities for such an application to improve both civilian and defense trauma treatment modalities.

  19. Solar neutrino results and present status

    International Nuclear Information System (INIS)

    Gorbachev, V.V.; Abdurashitov, J.N.; Gavrin, V.N.; Girin, S.V.; Gurkina, P.P.; Ibragimova, T.V.; Kalikhov, A.V.; Khairnasov, N.G.; Knodel, T.V.; Mirmov, I.N.; Shikhin, A.A.; Veretenkin, E.P.; Vermul, V.M.; Yants, V.E.; Zatsepin, G.T.; Bowles, T.J.; Teasdale, W.A.; Cherry, M.L.; Cleveland, B.T.; Elliott, S.R.

    2002-01-01

    The solar neutrino capture rate measured by the Russian-American Gallium Experiment on a metallic gallium target SAGE during the time from January 1990 through December 2000 is 77.0 +6.2 -6.2 +3.5 -3.0 SNU, where the uncertainties are statistical and systematic, respectively. The experimental procedures and data analysis are presented

  20. Gallium-67 scintigraphy and the Heart

    International Nuclear Information System (INIS)

    Garayt, D.

    1987-01-01

    Although gallium-67 was initially used for tumor imaging, clinical studies suggested its potential use as a method of detecting occult inflammatory lesions. The demonstration of diffuse myocardial uptake of gallium-67 during Lyme disease myocarditis is consistent with a pattern of diffuse myocarditis as seen in sarcoid myocarditis. Two cases are presented. A critical review of the various applications of gallium-67 scintigraphy to myocardium investigation is carried out [fr

  1. Aluminium, gallium, indium and thallium

    International Nuclear Information System (INIS)

    Brown, Paul L.; Ekberg, Christian

    2016-01-01

    Aluminium can exist in a number of oxyhydroxide mineral phases including corundum, diaspore, boehmite and gibbsite. The stability constants at zero ionic strength reported for Al(OH) 3 (aq) vary linearly with respect to the inverse of absolute temperature. A full suite of thermodynamic parameters is available for all aluminium phases and hydrolysis species. Gallium hydrolyses to a greater extent than aluminium, with the onset of hydrolysis reactions occurring just above a pHof 1. In fact, even though aluminium has the smallest ionic radius of this series of metals, it has the weakest hydrolysis species and oxide/hydroxide phases.This is due to the presence of stabilising d-orbitals in the heavier metals, gallium, indium and thallium(III). There are few available data for the stability constants of indium(III) hydrolysis species. Of those that are available, the range in the proposed stability constants covers many orders of magnitude.

  2. Gallium and copper radiopharmaceutical chemistry

    International Nuclear Information System (INIS)

    Green, M.A.; John, E.K.; Barnhart, A.J.

    1990-01-01

    Several isotopes of gallium and copper exhibit nuclear properties that make them attractive for applications in nuclear medicine, most notably Ga-67, Ga-68, Cu-67 and Cu-62. Of these, gamma-emitting Ga-67 has historically found the greatest clinical use, based on the observation that tracer gallium(III) citrate rapidly produces Ga-67 transferrin upon intravenous injection and then slowly affords selective Ga-67 localization in sites of abscess and certain tumors. Copper-67 has received attention as a potential label for tissue-selective monoclonal antibodies, since its associated γ-photons can be used for external imaging and its β - -emissions could be used for radiation therapy. Positron-emitting gallium-68 and copper-62, being available from parent/daughter generator systems, have attracted interest as potential labels for radiopharmaceuticals used in positron emission tomography (PET) because they could reduce the dependence of this imaging technology on hospital-based cyclotrons. The 10 min. half-life of Cu-62 is particularly well-suited to the time frame of PET studies of tissue perfusion, an application for which Cu(II)-bis(thiosemicarbazone) derivatives appear promising. The 68 min. half-life of Ga-68 makes it appropriate for PET studies over longer imaging time spans

  3. Gallium 67 uptake in thymic rebound

    International Nuclear Information System (INIS)

    Hurst, R.; Sabio, H.; Teates, C.D.

    1988-01-01

    We have reported a case of localized thymic enlargement and uptake of gallium 67 in a child who had received antineoplastic chemotherapy. The enlarged thymus showed normal histology, a picture consistent with thymic rebound after nonspecific stress. This case further demonstrates the need to consider thymic rebound as a cause of gallium 67 uptake in children with neoplastic diseases

  4. Gallium-67 citrate scan in extrapulmonary tuberculosis

    Energy Technology Data Exchange (ETDEWEB)

    Lin Wanyu [Taichung Veterans General Hospital (Taiwan). Dept. of Nuclear Medicine; Hsieh Jihfang [Chi-Mei Foundation Hospital, Tainan (Taiwan)

    1999-07-01

    Aim: Whole-body gallium scan was performed to evaluate the usefulness of gallium scan for detecting extrapulmonary tuberculosis (TB) lesions. Methods: Thirty-seven patients with extrapulmonary TB were included in this study. Four patients were found to have two lesions. Totally, 41 lesions were identified, including 19 TB arthritis, 8 spinal TB, 5 TB meningitis, 3 TB lymphadenopathy, 2 TB pericarditis, 1 TB peritonitis, 1 intestinal TB, 1 skin TB and 1 renal TB. Results: Of the 41 extrapulmonary TB lesions, gallium scan detected 32 lesions with a sensitivity of 78%. All the patients with TB meningitis showed negative gallium scan. When the five cases of TB meningitis were excluded, the detection sensitivity of gallium scan increased to 88.9% (32/36). Conclusion: Our data revealed that gallium scan is a convenient and useful method for evaluating extrapulmonary TB lesions other than TB-meningitis. We suggest that gallium scan be included in the clinical routine for patients with suspected extrapulmonary TB. (orig.) [German] Ziel: Es wurden Ganzkoerper-Gallium-Szintigramme angefertigt, um den Nutzen der Gallium-Szintigraphie zur Erfassung von extrapulmonalen Tuberkuloseherden (TB) zu erfassen. Methoden: 37 Patienten mit extrapulmonaler TB wurden eingeschlossen. 4 Patienten hatten 2 Laesionen. Insgesamt wurden 41 Laesionen identifiziert, hierunter 19 TB-Arthritis, 8 spinale TB, 5 TB-Meningitis, 3 TB-Lymphadenopathie, 2 TB-Perikarditis, 1 TB-Peritonitis, 1 intestinale TB, 1 Haut-TB und eine Nieren-TB. Ergebnisse: Von den 41 extrapulmonalen TB-Herden erfasste die Gallium-Szintigraphie 32 Herde mit einer Sensitivitaet von 78%. Alle Patienten mit TB-Meningitis zeigten einen negativen Gallium-Scan. Wenn die 5 Faelle mit TB-Meningitis ausgeschlossen wurden, stieg die Sensitivititaet der Gallium-Szintigraphie auf 88,9% (32/36). Schlussfolgerung: Die Daten zeigen, dass die Gallium-Szintigraphie eine einfache und nuetzliche Methode zur Erfassung extrapulmonaler TB-Herde ist

  5. Gallium Electromagnetic (GEM) Thrustor Concept and Design

    Science.gov (United States)

    Polzin, Kurt A.; Markusic, Thomas E.

    2006-01-01

    We describe the design of a new type of two-stage pulsed electromagnetic accelerator, the gallium electromagnetic (GEM) thruster. A schematic illustration of the GEM thruster concept is given in Fig. 1. In this concept, liquid gallium propellant is pumped into the first stage through a porous metal electrode using an electromagneticpump[l]. At a designated time, a pulsed discharge (approx.10-50 J) is initiated in the first stage, ablating the liquid gallium from the porous electrode surface and ejecting a dense thermal gallium plasma into the second state. The presence of the gallium plasma in the second stage serves to trigger the high-energy (approx.500 I), send-stage puke which provides the primary electromagnetic (j x B) acceleration.

  6. Gallium nitride on gallium oxide substrate for integrated nonlinear optics

    KAUST Repository

    Awan, Kashif M.; Dolgaleva, Ksenia; Mumthaz Muhammed, Mufasila; Roqan, Iman S.

    2017-01-01

    Gallium Nitride (GaN), being a direct bandgap semiconductor with a wide bandgap and high thermal stability, is attractive for optoelectronic and electronic applications. Furthermore, due to its high optical nonlinearity — the characteristic of all 111-V semiconductors — GaN is also expected to be a suitable candidate for integrated nonlinear photonic circuits for a plethora of apphcations, ranging from on-chip wavelength conversion to quantum computing. Although GaN devices are in commercial production, it still suffers from lack of a suitable substrate material to reduce structural defects like high densities of threading dislocations (TDs), stacking faults, and grain boundaries. These defects significandy deteriorate the optical quality of the epi-grown GaN layer, since they act as non-radiative recombination centers. Recent studies have shown that GaN grown on (−201) β-Gallium Oxide (Ga2O3) has superior optical quality due to a better lattice matching as compared to GaN grown on Sapphire (Al2O3) [1-3]. In this work, we report on the fabrication of GaN waveguides on GaiOj substrate and their optical characterization to assess their feasibihty for efficient four-wave mixing (FWM).

  7. Gallium nitride on gallium oxide substrate for integrated nonlinear optics

    KAUST Repository

    Awan, Kashif M.

    2017-11-22

    Gallium Nitride (GaN), being a direct bandgap semiconductor with a wide bandgap and high thermal stability, is attractive for optoelectronic and electronic applications. Furthermore, due to its high optical nonlinearity — the characteristic of all 111-V semiconductors — GaN is also expected to be a suitable candidate for integrated nonlinear photonic circuits for a plethora of apphcations, ranging from on-chip wavelength conversion to quantum computing. Although GaN devices are in commercial production, it still suffers from lack of a suitable substrate material to reduce structural defects like high densities of threading dislocations (TDs), stacking faults, and grain boundaries. These defects significandy deteriorate the optical quality of the epi-grown GaN layer, since they act as non-radiative recombination centers. Recent studies have shown that GaN grown on (−201) β-Gallium Oxide (Ga2O3) has superior optical quality due to a better lattice matching as compared to GaN grown on Sapphire (Al2O3) [1-3]. In this work, we report on the fabrication of GaN waveguides on GaiOj substrate and their optical characterization to assess their feasibihty for efficient four-wave mixing (FWM).

  8. Gallium determination in biological samples

    International Nuclear Information System (INIS)

    Stulzaft, O.; Maziere, B.; Ly, S.

    1980-01-01

    A sensitive, simple and time-saving method has been developed for the neutron activation analysis of gallium at concentrations around 10 -4 ppm in biological tissues. After a 24-hour irradiation in a thermal neutron flux of 2.8x10 13 nxcm -2 xs -1 and a purification by ion-exchange chromatography to eliminate troublesome elements such as sodium, iron and copper, the 72 Ga activity is measured with enough accuracy for the method to be applicable in animal physiology and clinical toxicology. (author)

  9. Thermodynamics of gallium arsenide electrodeposition

    International Nuclear Information System (INIS)

    Perrault, G.G.

    1986-01-01

    Gallium Arsenide is well known as a very interesting compound for photoelectrical devices. Up to now, it has been prepared mostly by high temperature technology, and the authors considered that it might be of interest to set up an electrodeposition technique suitable to prepare thin layers of this compound. A reaction sequence similar to the one observed for Cadmium Sulfide or Cadmium Telluride could be considered. In these cases, the metal chalcogenide is obtained from the precipitation of the metal ions dissolved in the solutions by the reduction product of the metalloidic compound

  10. Design and testing of the measuring equipment for the detection of 71Ge and 69Ge within the gallium-solar-neutrino experiment

    International Nuclear Information System (INIS)

    Huebner, M.

    1980-01-01

    A low level measuring system has been developed for the Ga-solar-neutrino experiment, to detect the reaction 71 Ga (νsub(e),e - ) 71 Ge by the decay 71 Ge (Tsub(1/2) = 11. 4 d, 100% electron capture). An estimate based on the solar standard model gives 15 71 Ge atoms produced by solar neutrinos (pp and pep). As a monitor for background reactions in the target, the detectability of the 69 Ga (p,n) 69 Ge reaction by the decay 69 Ge (Tsub(1/2) = 39 h, 37% β + -decay, 63% electron capture) has been considered. To test the system, the detectors are mounted in a low level laboratory lead box. (orig./WB) [de

  11. Subcutaneous injection of thallium-201 chloride and gallium-67 citrate at acupuncture point K-3; An animal experiment and human-being study

    Energy Technology Data Exchange (ETDEWEB)

    Johg, Shiang-Bin; Wu, Chung-Chieng; Chen, Ming-Feng; Wu, Sheng-Nan (Kaohsiung Medical Coll., Taiwan (China))

    1992-09-01

    Subcutaneous (SC) injection of [sup 99m]Tc pertechnetate ([sup 99m]Tc) at acupuncture points K-3 is a new method of lower-limb radionuclide venography. To investigate the mechanism of absorption of [sup 99m]Tc from SC injected sites into vascular system, various radioisotopes such as [sup 201]Tl chloride ([sup 201]Tl) and [sup 67]Ga citrate ([sup 67]Ga) were SC injected at K-3 points in animal and human-beings experiments. It was found that [sup 99m]Tc and [sup 201]Tl were absorbed rapidly from K-3 points through venous system and into whole body soft tissue. However, [sup 67]Ga with a larger effective ionic radius than [sup 201]Tl was not absorbed throughout the observation of 5 minutes. Furthermore, intravenous administration of digitalis, a Na[sup +]-K[sup +] pump blocker, did not inhibit the absorption of [sup 99m]Tc and [sup 201]Tl after SC injection at K-3 points. These results suggest that absorption of radionuclides on SC injection at K-3 points is mainly through the passive pathway of diffusion rather than the active transport, and the effective ionic radius may be a major factor influencing the absorption rate of the radionuclides. (author).

  12. Testing of gallium arsenide solar cells on the CRRES vehicle

    International Nuclear Information System (INIS)

    Trumble, T.M.

    1985-01-01

    A flight experiment was designed to determine the optimum design for gallium arsenide (GaAs) solar cell panels in a radiation environment. Elements of the experiment design include, different coverglass material and thicknesses, welded and soldered interconnects, different solar cell efficiencies, different solar cell types, and measurement of annealing properties. This experiment is scheduled to fly on the Combined Release and Radiation Effects Satellite (CRRES). This satellite will simultaneously measure the radiation environment and provide engineering data on solar cell degradation that can be directly related to radiation damage

  13. Gallium-67 citrate scan in extrapulmonary tuberculosis

    International Nuclear Information System (INIS)

    Lin Wanyu

    1999-01-01

    Aim: Whole-body gallium scan was performed to evaluate the usefulness of gallium scan for detecting extrapulmonary tuberculosis (TB) lesions. Methods: Thirty-seven patients with extrapulmonary TB were included in this study. Four patients were found to have two lesions. Totally, 41 lesions were identified, including 19 TB arthritis, 8 spinal TB, 5 TB meningitis, 3 TB lymphadenopathy, 2 TB pericarditis, 1 TB peritonitis, 1 intestinal TB, 1 skin TB and 1 renal TB. Results: Of the 41 extrapulmonary TB lesions, gallium scan detected 32 lesions with a sensitivity of 78%. All the patients with TB meningitis showed negative gallium scan. When the five cases of TB meningitis were excluded, the detection sensitivity of gallium scan increased to 88.9% (32/36). Conclusion: Our data revealed that gallium scan is a convenient and useful method for evaluating extrapulmonary TB lesions other than TB-meningitis. We suggest that gallium scan be included in the clinical routine for patients with suspected extrapulmonary TB. (orig.) [de

  14. Gallium-67 scintigraphy in borderline lepromatous leprosy

    International Nuclear Information System (INIS)

    Mouratidis, B.; Lomas, F.E.

    1993-01-01

    A middle aged woman with a pyrexia of unknown origin was shown to have borderline lepromatous leprosy. Early gallium-67 scintigraphy demonstrated increased uptake in the subcutaneous tissues of the face and thighs. As a result of these findings skin biopsy was obtained from the right thigh which gave a diagnosis of borderline lepromatous leprosy. The authors have been unable to find other reports of gallium-67 scintigraphy in leprosy but the pattern of gallium-67 distribution should suggest the diagnosis. 5 refs., 1 fig

  15. Study of current instabilities in high resistivity gallium arsenide

    International Nuclear Information System (INIS)

    Barraud, A.

    1968-01-01

    We have shown the existence and made a study of the current oscillations produced in high-resistivity gallium arsenide by a strong electric field. The oscillations are associated with the slow travelling of a region of high electrical field across the whole sample. An experimental study of the properties of these instabilities has made it possible for us to distinguish this phenomenon from the Gunn effect, from acoustic-electric effects and from contact effects. In order to account for this type of instability, a differential trapping mechanism involving repulsive impurities is proposed; this mechanism can reduce the concentration of charge carriers in the conduction band at strong electrical fields and can lead to the production of a high-field domain. By developing this model qualitatively we have been able to account for all the properties of high-resistance gallium arsenide crystals subjected to a strong electrical field: increase of the Hall constant, existence of a voltage threshold for these oscillations, production of domains of high field, low rate of propagation of these domains, and finally the possibility of inverting the direction of the propagation of the domain without destroying the latter. A quantitative development of the model makes it possible to calculate the various characteristic parameters of these instabilities. Comparison with experiment shows that there is a good agreement, the small deviations coming especially from the lack of knowledge concerning transport properties in gallium arsenide subjected to high fields. From a study of this model, it appears that the instability phenomenon can occur over a wide range of repulsive centre concentrations, and also for a large range of resistivities. This is the reason why it appears systematically in gallium arsenide of medium and high resistivity. (authors) [fr

  16. Radiochemical neutron activation analysis based multi-elemental analysis of high purity gallium

    International Nuclear Information System (INIS)

    Tashimova, F.A.; Sadikov, I.I; Salimov, M.I.; Zinov'ev, V.G.

    2006-01-01

    Full text: Gallium is one of the widely used materials in semiconductor and optoelectronics industry. Gallium is used to produce infrared detectors, piezoelectric sensors, high- and low-temperature transistors for space and defense technology. One of the most important requirements for semiconductor materials of gallium compounds is an excessive high purity for layers and films. Information on impurities (type of an impurity, concentration, character of distribution) is important as for better understanding of the physical and chemical processes taking place in formed semiconductor structures and for the 'know-how' of devices on their basis. The object of this work is to develop radiochemical neutron activation technique for analysis of high purity gallium. Irradiation of 0.1 g of gallium sample in neutron flux of 5·10 13 cm -2 s -1 for 5 hours will result in induced activity of more than 10 8 Bq, due to 72 Ga radionuclide, half-life of which is 14.1 hours. Therefore to perform instrumental NAA of gallium long period (10 day) cooling is required, and high sensitive determination of elements producing short- and long-lived radionuclides (T 1/2 72 Ga. We have studied the behavior of gallium in extraction-chromatographic system 'TBP-HCl'. The experiments have shown that higher factor of distribution (D) and capacity on gallium can be achieved when 'TBP-4M HCl' system is used. However more than 10 trace elements have high D and thus they cannot be separated from 72 Ga. To resolve the problem and increase the number of separated trace elements we have used preliminary satisfaction of chromatographic column with tellurium, which has D higher than the most of elements in 'TBP-4M HCl' system and thus suppresses extraction of elements. Distribution profile of gallium along the column and elution curve of 25 trace elements have been measured. Chemical yields of separated elements measured by using radiotracers are more than 93%. On the basis of the carried out researches

  17. Gallium-67 activity in bronchoalveolar lavage fluid in sarcoidosis

    International Nuclear Information System (INIS)

    Trauth, H.A.; Heimes, K.; Schubotz, R.; von Wichert, P.

    1986-01-01

    Roentgenograms and gallium-67 scans and gallium-67 counts of BAL fluid samples, together with differential cell counts, have proved to be useful in assessing activity and lung involvement in sarcoidosis. In active pulmonary sarcoidosis gallium-67 scans are usually positive. Quantitation of gallium-67 uptake in lung scans, however, may be difficult. Because gallium-67 uptake and cell counts in BAL fluid may be correlated, we set out to investigate gallium-67 activity in BAL fluid recovered from patient of different groups. Sixteen patients with recently diagnosed and untreated sarcoidosis, nine patients with healthy lungs, and five patients with CFA were studied. Gallium-67 uptake of the lung, gallium-67 activity in the lavage fluid, SACE and LACE levels, and alpha 1-AT activity were measured. Significantly more gallium-67 activity was found in BAL fluid from sarcoidosis patients than in that from CFA patients (alpha = .001) or patients with healthy lungs (alpha = .001). Gallium-67 activity in BAL fluid could be well correlated with the number of lymphocytes in BAL fluid, but poorly with the number of macrophages. Subjects with increased levels of SACE or serum alpha 1-AT showed higher lavage gallium-67 activity than did normals, but no correlation could be established. High gallium-67 activity in lavage fluid may be correlated with acute sarcoidosis or physiological deterioration; low activity denotes change for the better. The results show that gallium-67 counts in BAL fluid reflects the intensity of gallium-67 uptake and thus of activity of pulmonary sarcoidosis

  18. NIM Realization of the Gallium Triple Point

    Science.gov (United States)

    Xiaoke, Yan; Ping, Qiu; Yuning, Duan; Yongmei, Qu

    2003-09-01

    In the last three years (1999 to 2001), the gallium triple-point cell has been successfully developed, and much corresponding research has been carried out at the National Institute of Metrology (NIM), Beijing, China. This paper presents the cell design, apparatus and procedure for realizing the gallium triple point, and presents studies on the different freezing methods. The reproducibility is 0.03 mK, and the expanded uncertainty of realization of the gallium triple point is evaluated to be 0.17 mK (p=0.99, k=2.9). Also, the reproducibility of the gallium triple point was compared with that of the triple point of water.

  19. Glutathione role in gallium induced toxicity

    African Journals Online (AJOL)

    Asim

    2012-01-26

    Jan 26, 2012 ... 1Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Gomal University, D.I. Khan, ... Decrease in GSH level was dependant on gallium nitrate concentration. .... This 2 ml mixture sample was centrifuged at 1000.

  20. Properties of gallium lanthanum sulphide glass

    OpenAIRE

    Bastock, P.; Craig, C.; Khan, K.; Weatherby, E.; Yao, J.; Hewak, D.W.

    2015-01-01

    A series of gallium lanthanum sulphide (GLS) glasses has been studied in order to ascertain properties across the entire glass forming region. This is the first comprehensive study of GLS glass over a wide compositional range.

  1. Glutathione role in gallium induced toxicity

    African Journals Online (AJOL)

    Asim

    2012-01-26

    GSH) present in tissues. It is very important and interesting to study the reaction of gallium nitrate and glutathione as biomarker of glutathione role in detoxification and conjugation in whole blood components (plasma and ...

  2. Metal Contacts to Gallium Arsenide.

    Science.gov (United States)

    Ren, Fan

    1991-07-01

    While various high performance devices fabricated from the gallium arsenide (GaAs) and related materials have generated considerable interest, metallization are fundamental components to all semiconductor devices and integrated circuits. The essential roles of metallization systems are providing the desired electrical paths between the active region of the semiconductor and the external circuits through the metal interconnections and contacts. In this work, in-situ clean of native oxide, high temperature n-type, low temperature n-type and low temperature p-type ohmic metal systems have been studied. Argon ion mill was used to remove the native oxide prior to metal deposition. For high temperature process n-type GaAs ohmic contacts, Tungsten (W) and Tungsten Silicide (WSi) were used with an epitaxial grown graded Indium Gallium Arsenide (InGaAs) layer (0.2 eV) on GaAs. In addition, refractory metals, Molybdenum (Mo), was incorporated in the Gold-Germanium (AuGe) based on n-type GaAs ohmic contacts to replace conventional silver as barrier to prevent the reaction between ohmic metal and chlorine based plasma as well as the ohmic metallization intermixing which degrades the device performance. Finally, Indium/Gold-Beryllium (In/Au-Be) alloy has been developed as an ohmic contact for p-type GaAs to reduce the contact resistance. The Fermi-level pinning of GaAs has been dominated by the surface states. The Schottky barrier height of metal contacts are about 0.8 V regardless of the metal systems. By using p-n junction approach, barrier height of pulsed C-doped layers was achieved as high as 1.4 V. Arsenic implantation into GaAs method was also used to enhance the barrier height of 1.6 V.

  3. Sodium enhances indium-gallium interdiffusion in copper indium gallium diselenide photovoltaic absorbers.

    Science.gov (United States)

    Colombara, Diego; Werner, Florian; Schwarz, Torsten; Cañero Infante, Ingrid; Fleming, Yves; Valle, Nathalie; Spindler, Conrad; Vacchieri, Erica; Rey, Germain; Guennou, Mael; Bouttemy, Muriel; Manjón, Alba Garzón; Peral Alonso, Inmaculada; Melchiorre, Michele; El Adib, Brahime; Gault, Baptiste; Raabe, Dierk; Dale, Phillip J; Siebentritt, Susanne

    2018-02-26

    Copper indium gallium diselenide-based technology provides the most efficient solar energy conversion among all thin-film photovoltaic devices. This is possible due to engineered gallium depth gradients and alkali extrinsic doping. Sodium is well known to impede interdiffusion of indium and gallium in polycrystalline Cu(In,Ga)Se 2 films, thus influencing the gallium depth distribution. Here, however, sodium is shown to have the opposite effect in monocrystalline gallium-free CuInSe 2 grown on GaAs substrates. Gallium in-diffusion from the substrates is enhanced when sodium is incorporated into the film, leading to Cu(In,Ga)Se 2 and Cu(In,Ga) 3 Se 5 phase formation. These results show that sodium does not decrease per se indium and gallium interdiffusion. Instead, it is suggested that sodium promotes indium and gallium intragrain diffusion, while it hinders intergrain diffusion by segregating at grain boundaries. The deeper understanding of dopant-mediated atomic diffusion mechanisms should lead to more effective chemical and electrical passivation strategies, and more efficient solar cells.

  4. 67Gallium • the D,etection and Localization

    African Journals Online (AJOL)

    1971-12-11

    Dec 11, 1971 ... gallium and its compounds was first aroused when it was noted that this element is contained .... MATERIALS AND METHODS. ;;'Gallium citrate was .... another in a patient with a pathological fracture of the right humerus that ...

  5. Window structure for passivating solar cells based on gallium arsenide

    Science.gov (United States)

    Barnett, Allen M. (Inventor)

    1985-01-01

    Passivated gallium arsenide solar photovoltaic cells with high resistance to moisture and oxygen are provided by means of a gallium arsenide phosphide window graded through its thickness from arsenic rich to phosphorus rich.

  6. Normal vibrations in gallium arsenide

    International Nuclear Information System (INIS)

    Dolling, G.; Waugh, J.L.T.

    1964-01-01

    The triple axis crystal spectrometer at Chalk River has been used to observe coherent slow neutron scattering from a single crystal of pure gallium arsenide at 296 o K. The frequencies of normal modes of vibration propagating in the [ζ00], (ζζζ], and (0ζζ] crystal directions have been determined with a precision of between 1 and 2·5 per cent. A limited number of normal modes have also been studied at 95 and 184 o K. Considerable difficulty was experienced in obtaining welt resolved neutron peaks corresponding to the two non-degenerate optic modes for very small wave-vector, particularly at 296 o K. However, from a comparison of results obtained under various experimental conditions at several different points in reciprocal space, frequencies (units 10 12 c/s) for these modes (at 296 o K) have been assigned: T 8·02±0·08 and L 8·55±02. Other specific normal modes, with their measured frequencies are (a) (1,0,0): TO 7·56 ± 008, TA 2·36 ± 0·015, LO 7·22 ± 0·15, LA 6·80 ± 0·06; (b) (0·5, 0·5, 0·5): TO 7·84 ± 0·12, TA 1·86 ± 0·02, LO 7·15 ± 0·07, LA 6·26 ± 0·10; (c) (0, 0·65, 0·65): optic 8·08 ±0·13, 7·54 ± 0·12 and 6·57 ± 0·11, acoustic 5·58 ± 0·08, 3·42 · 0·06 and 2·36 ± 004. These results are generally slightly lower than the corresponding frequencies for germanium. An analysis in terms of various modifications of the dipole approximation model has been carried out. A feature of this analysis is that the charge on the gallium atom appears to be very small, about +0·04 e. The frequency distribution function has been derived from one of the force models. (author)

  7. Normal vibrations in gallium arsenide

    Energy Technology Data Exchange (ETDEWEB)

    Dolling, G; Waugh, J L T

    1964-07-01

    The triple axis crystal spectrometer at Chalk River has been used to observe coherent slow neutron scattering from a single crystal of pure gallium arsenide at 296{sup o}K. The frequencies of normal modes of vibration propagating in the [{zeta}00], ({zeta}{zeta}{zeta}], and (0{zeta}{zeta}] crystal directions have been determined with a precision of between 1 and 2{center_dot}5 per cent. A limited number of normal modes have also been studied at 95 and 184{sup o}K. Considerable difficulty was experienced in obtaining welt resolved neutron peaks corresponding to the two non-degenerate optic modes for very small wave-vector, particularly at 296{sup o}K. However, from a comparison of results obtained under various experimental conditions at several different points in reciprocal space, frequencies (units 10{sup 12} c/s) for these modes (at 296{sup o}K) have been assigned: T 8{center_dot}02{+-}0{center_dot}08 and L 8{center_dot}55{+-}02. Other specific normal modes, with their measured frequencies are (a) (1,0,0): TO 7{center_dot}56 {+-} 008, TA 2{center_dot}36 {+-} 0{center_dot}015, LO 7{center_dot}22 {+-} 0{center_dot}15, LA 6{center_dot}80 {+-} 0{center_dot}06; (b) (0{center_dot}5, 0{center_dot}5, 0{center_dot}5): TO 7{center_dot}84 {+-} 0{center_dot}12, TA 1{center_dot}86 {+-} 0{center_dot}02, LO 7{center_dot}15 {+-} 0{center_dot}07, LA 6{center_dot}26 {+-} 0{center_dot}10; (c) (0, 0{center_dot}65, 0{center_dot}65): optic 8{center_dot}08 {+-}0{center_dot}13, 7{center_dot}54 {+-} 0{center_dot}12 and 6{center_dot}57 {+-} 0{center_dot}11, acoustic 5{center_dot}58 {+-} 0{center_dot}08, 3{center_dot}42 {center_dot} 0{center_dot}06 and 2{center_dot}36 {+-} 004. These results are generally slightly lower than the corresponding frequencies for germanium. An analysis in terms of various modifications of the dipole approximation model has been carried out. A feature of this analysis is that the charge on the gallium atom appears to be very small, about +0{center_dot}04 e. The

  8. Thermodynamic and transport properties of liquid gallium

    International Nuclear Information System (INIS)

    Park, H.Y.; Jhon, M.S.

    1982-01-01

    The significant structure theory of liquids has been successfully applied to liquid gallium. In this work, we have assumed that two structures exist simultaneously in liquid gallium. One is considerec as loosely close packed β-Ga-like structure and the other is remainder of solid α-Ga or α-Ga-like structure. This two structural model is introduced to construct the liquid partition function. Using the partition function, the thermodynamic and transport properties are calculated ever a wide temperature range. The calculated results are quite satisfactory when compared with the experimental results. (Author)

  9. Gallium uptake in myositis ossificans. Potential pitfalls in diagnosis

    International Nuclear Information System (INIS)

    Salzman, L.; Lee, V.W.; Grant, P.

    1987-01-01

    Seven cases of gallium uptake in myositis ossificans are described. Gallium scans are done frequently in paraplegics, quadriplegics, and comatose patients to look for occult infection. It is important to be aware of possible gallium uptake in myositis ossificans, particularly in the extremities, which is frequent in these patients. Gallium uptake may be present prior to any abnormalities seen on plain films or CT scans. It is important to correlate roentgenograms with abnormal gallium scans, particularly in the extremities, to avoid potential pitfalls in diagnosis and prevent unnecessary antibiotic treatment. A bone scan should be obtained whenever possible, particularly when roentgenograms are negative, to confirm the diagnosis

  10. 67Gallium lung scans in progressive systemic sclerosis

    International Nuclear Information System (INIS)

    Baron, M.; Feiglin, D.; Hyland, R.; Urowitz, M.B.; Shiff, B.

    1983-01-01

    67 Gallium lung scans were performed in 19 patients with progressive systemic sclerosis (scleroderma). Results were expressed quantitatively as the 67 Gallium Uptake Index. The mean total pulmonary 67 Gallium Uptake Index in patients was significantly higher than that in controls (41 versus 25), and 4 patients (21%) fell outside the normal range. There were no clinical or laboratory variables that correlated with the 56 Gallium uptake. Increased pulmonary 67 Gallium uptake in scleroderma may prove useful as an index of pulmonary disease activity

  11. EDXRF and TXRF determination of gallium in gallium-uranium matrix

    International Nuclear Information System (INIS)

    Misra, N.L.; Sanjay Kumar, S.; Dhara, Sangita; Aggarwal, S.K.; Venugopal, V.

    2009-01-01

    Energy Dispersive X-Ray Fluorescence (EDXRF) and Total Reflection X-ray Fluorescence (TXRF) methods for determination of Gallium in Gallium-Uranium matrix have been developed. For EDXRF determinations, 200 μL of standards/samples mixed with internal standard copper were dispersed on 30 mm diameter absorbent sheet so that it behaves like a thin film of the sample. The Gallium amounts in samples were determined from their EDXRF spectra using a calibration plot. For TXRF determinations, samples were taken on flat polished quartz sample supports and Gallium was determined in conventional way. For EDXRF and TXRF determinations, the average precision and accuracy obtained for Ga determinations was better than 3% (1σ). (author)

  12. Two-Dimensional Modeling of Aluminum Gallium Nitride/Gallium Nitride High Electron Mobility Transistor

    National Research Council Canada - National Science Library

    Holmes, Kenneth

    2002-01-01

    Gallium Nitride (GaN) High Electron Mobility Transistors (HEMT's) are microwave power devices that have the performance characteristics to improve the capabilities of current and future Navy radar and communication systems...

  13. Application of extraction of gallium molybdotungstate HPA for their investigation in solutions and gallium determination

    International Nuclear Information System (INIS)

    Kol'tsova, E.G.; Vakulich, A.N.; Tsyganok, L.P.

    2001-01-01

    Extraction of gallium molybdotungstate heteropolyacids and their associates with a row of triphenylmethane dyes, use of extraction for study of complexing in Mo 6 -W 6 -Ga 3+ -H 3 O + system are investigated. Research of optimal analytical states and development of extraction spectrophotometric methods of gallium determination are done. It is shown that increase of Mo 6 part in heteropolyanion improves solvation interaction of heteropolyacids with organic solvents elevating extraction properties of polyanion [ru

  14. The role of gallium-67 in Hodgkin's disease

    International Nuclear Information System (INIS)

    Bogart, Jeffrey A.; Chung, T. Chung; Mariados, Neil F.

    1996-01-01

    Purpose/Objective: Although widely used, the value of gallium imaging in managing Hodgkin's lymphoma remains unclear. Methods: Retrospective review of gallium and treatment data in patients with Hodgkin's disease between January 1990 and July 1995. Results: Eighty-six of 101 patients had Ga-67 imaging. Stage was as follows: 1A-11 patients, 1B - 2, 2A - 27, 2B - 22, 3A - 10, 3B - 5, 4A - 3 and 4B - 6. Sixty-two patients had staging gallium scans and 15% of tumors were not gallium avid. Two patients were upstaged based on gallium scan. Five patients had positive laparotomy and all had negative abdominal gallium exams. Three studies had false positive lesions. Initial therapy was assessed with gallium in 61 patients and 45 had complete response. Tumor recurred in 36% ((10(28))) of patients gallium negative after 3-6 cycles of chemotherapy, with no recurrences in 17 patients gallium negative after radiotherapy or chemo radiation. Six of 7 patients with focal gallium uptake after chemotherapy received radiotherapy and all remain disease free. Seven patients had persistent or progressive gallium-avid tumor after chemotherapy correlating with clinical disease. Two patients had false positive exams after radiotherapy. Twenty-two patients had gallium scans at recurrence. One scan was (false) negative and in two cases, gallium imaging was the initial evidence of recurrent tumor. Conclusion: Ga-67 imaging may help confirm the presence of active Hodgkin's disease, but was unreliable in defining disease remission after chemotherapy in this study population. Prospective studies may help define the role of gallium scans

  15. Long-chain amine-templated synthesis of gallium sulfide and gallium selenide nanotubes

    Science.gov (United States)

    Seral-Ascaso, A.; Metel, S.; Pokle, A.; Backes, C.; Zhang, C. J.; Nerl, H. C.; Rode, K.; Berner, N. C.; Downing, C.; McEvoy, N.; Muñoz, E.; Harvey, A.; Gholamvand, Z.; Duesberg, G. S.; Coleman, J. N.; Nicolosi, V.

    2016-06-01

    We describe the soft chemistry synthesis of amine-templated gallium chalcogenide nanotubes through the reaction of gallium(iii) acetylacetonate and the chalcogen (sulfur, selenium) using a mixture of long-chain amines (hexadecylamine and dodecylamine) as a solvent. Beyond their role as solvent, the amines also act as a template, directing the growth of discrete units with a one-dimensional multilayer tubular nanostructure. These new materials, which broaden the family of amine-stabilized gallium chalcogenides, can be tentatively classified as direct large band gap semiconductors. Their preliminary performance as active material for electrodes in lithium ion batteries has also been tested, demonstrating great potential in energy storage field even without optimization.We describe the soft chemistry synthesis of amine-templated gallium chalcogenide nanotubes through the reaction of gallium(iii) acetylacetonate and the chalcogen (sulfur, selenium) using a mixture of long-chain amines (hexadecylamine and dodecylamine) as a solvent. Beyond their role as solvent, the amines also act as a template, directing the growth of discrete units with a one-dimensional multilayer tubular nanostructure. These new materials, which broaden the family of amine-stabilized gallium chalcogenides, can be tentatively classified as direct large band gap semiconductors. Their preliminary performance as active material for electrodes in lithium ion batteries has also been tested, demonstrating great potential in energy storage field even without optimization. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01663d

  16. A comparison of gallium-67 citrate scintigraphy and indium-111 labelled leukocyte imaging for the diagnosis of prosthetic joint infection. Preliminary results

    International Nuclear Information System (INIS)

    McKillop, J.H.; Cuthbert, G.F.; Gray, H.W.; McKay, Iain; Sturrock, R.D.

    1982-01-01

    Preliminary experience in comparing Gallium-67 imaging in patients with a painful prosthetic joint to the findings on Indium-111 labelled leukocyte imaging is reported. In the small series of patients so far studied, no clear advantage has emerged for either Gallium-67 or Indium-111 leukocyte imaging in terms of sensitivity or specificity for joint prosthesis infection. Should a larger group confirm the preliminary findings, Gallium-67 imaging may be preferable to Indium-111 leukocyte imaging in the patient with the painful joint prosthesis, in view of the greater simplicity of the former technique

  17. Optical characteristics of a gallium laser plasma

    International Nuclear Information System (INIS)

    Shuaibov, A.K.; Shimon, L.L.; Dashchenko, A.I.; Shevera, I.V.; Chuchman, M.P.

    2001-01-01

    Results are presented from studies of the emission from an erosion gallium laser plasma at a moderate intensity (W = (1-5) x 10 8 W/cm 2 ) of a 1.06-μm laser radiation. It is shown that, under these conditions, the lower excited states of gallium atoms are populated most efficiently. Among the ions, only the most intense GaII lines are observed in the emission spectrum. The populations of GaI and GaII excited states are not related to direct electron excitation, but are determined by the recombination of gallium ions with slow electrons. The recombination times of GaIII and GaII ions in the core of the plasma jet are determined from the waveforms of emission in the GaII and GaI spectral lines and are equal to 10 and 140 ns, respectively. The results obtained are of interest for spectroscopic diagnostics of an erosion plasma produced from gallium-containing layered crystals during the laser deposition of thin films

  18. Gallium-positive Lyme disease myocarditis

    International Nuclear Information System (INIS)

    Alpert, L.I.; Welch, P.; Fisher, N.

    1985-01-01

    In the course of a work-up for fever of unknown origin associated with intermittent arrhythmias, a gallium scan was performed which revealed diffuse myocardial uptake. The diagnosis of Lyme disease myocarditis subsequently was confirmed by serologic titers. One month following recovery from the acute illness, the abnormal myocardial uptake completely resolved

  19. Temperature-dependent structure evolution in liquid gallium

    International Nuclear Information System (INIS)

    Xiong, L.H.; Wang, X.D.; Yu, Q.; Zhang, H.; Zhang, F.; Sun, Y.; Cao, Q.P.; Xie, H.L.; Xiao, T.Q.; Zhang, D.X.; Wang, C.Z.; Ho, K.M.

    2017-01-01

    Temperature-dependent atomistic structure evolution of liquid gallium (Ga) has been investigated by using in situ high energy X-ray diffraction experiment and ab initio molecular dynamics simulation. Both experimental and theoretical results reveal the existence of a liquid structural change around 1000 K in liquid Ga. Below and above this temperature the liquid exhibits differences in activation energy for self-diffusion, temperature-dependent heat capacity, coordination numbers, density, viscosity, electric resistivity and thermoelectric power, which are reflected from structural changes of the bond-orientational order parameter Q_6, fraction of covalent dimers, averaged string length and local atomic packing. This finding will trigger more studies on the liquid-to-liquid crossover in metallic melts. - Graphical abstract: Atomistic structure evolution of liquid gallium has been investigated by using in situ high energy X-ray diffraction and ab initio molecular dynamics simulations, which both demonstrate the existence of a liquid structural change together with reported density, viscosity, electric resistivity and absolute thermoelectric power data.

  20. Soviet/Russian-American space cooperation

    Science.gov (United States)

    Karash, Yuri Y.

    This dissertation seeks to answer two questions: (1) what are the necessary conditions for the emergence of meaningful space cooperation between Russia and the United States, and (2) might this cooperation continue developing on its own merit, contributing to the further rapprochement between the two countries, even if the conditions that originated the cooperation were to change? The study examines the entire space era up to this point, 1957 to 1997, from the first satellite launch through the joint U.S.-Russian work on the ISS project. It focuses on the analysis of three distinct periods of possible and real cooperation between the United States and the Soviet Union/Russia. The first possibility for a limited Soviet-American cooperation in space emerged in the late 1950s, together with the space age, and continued until the mid-1960s. The major potential joint project of this period was a human expedition to the Moon. The global competition/confrontation between the two countries prevented actual cooperation. The second period was from the late 1960s until 1985 with consideration of experimental docking missions, including the docking of a reusable U.S. shuttle to a Soviet Salyut-type station. The global U.S.-Soviet competition still continued, but the confrontation was replaced by detente for a brief period of time lasting from the end of 1960s until mid-1970s. Detente gave the first example of U.S.-Soviet cooperation in space---the Apollo-Soyuz joint space flight (ASTP) which took place in 1975. However, the lack of interest of political leaderships in continuation of broad-scale cooperation between the two countries, and the end of detente, removed ASTP-like projects out of question at least until 1985. The third period started together with Mikhail Gorbachev's Perestroika in 1985 and continues until now. It involves almost a hundred of joint space projects both at the governmental and at the private sectors levels. The mainstream of the joint activities became U.S.-Russian work on the International Space Station (ISS). The interest of the Kremlin and White House in making space an "area of common interests" for the two countries, the interest of U.S. and Russian space communities in meaningful cooperation with each other, and the interdependence of the two countries within the ISS project, give hope that the U.S.-Russian cooperation will finally develop a long-term character.

  1. Russian-American venture designs new reactor

    International Nuclear Information System (INIS)

    Newman, P.

    1994-01-01

    Russian and American nuclear energy experts have completed a joint design study of a small, low-cost and demonstrably accident-proof reactor that they say could revolutionize the way conventional reactors are designed, marketed and operated. The joint design is helium-cooled and graphite-moderated and has a power density of 3 MWt/cubic meter, which is significantly less than the standard American reactor. A prototype of this design should be operating in Chelyabinsk by June 1996

  2. Dose dependent disposition of gallium-67 in rats

    International Nuclear Information System (INIS)

    Gautam, S.R.

    1982-01-01

    Radioactive gallium-67 has been employed as a diagnostic and follow-up agent for cancer therapy. Currently gallium nitrate is undergoing Phase I clinical studies. A million fold increase in the concentration of the carrier gallium citrate over the range of carrier-free gallium-67 (pgm) to 1.0 μg caused no significant alteration in the disposition of gallium-67 in rats.Gallium-67 was eliminated from blood with a biological t1/2 of 4.1 days. A linear tissue binding profile was observed for gallium-67 over this concentration range. A multi-compartment pharmacokinetic model was developed in which all the tissues studied were treated as separate compartments. At 1.0 mg dose level, significant alteration in the disposition of gallium-67 was observed in rats, > 95% of the initial radioactivity was characteristic reappearance of the radioactivity in the blood approximately 4 hours after dosing leading to a ''hump'' in the blood concentration-time profiles. Following the 1.0 mg dose low tissue levels were observed, except for the kidneys, which contained about 8% of the administered dose per gram of the tissue one-half hour after dosing. A non-linear tissue binding profile was observed to be associated with gallium at high doses. It was hypothesized that the rapid loss of gallium-67 from the vascular system following the high doses of gallium citrate was due to the accumulation of the drug in the kidneys where it was eventually eliminated via urine. The kidneys thus would act as a temporary storage site for gallium. It was concluded that the dose-related renal toxicity associated with gallium therapy may be attributed to the kidney's role as a temporary storage site following high doses

  3. Indium gallium nitride/gallium nitride quantum wells grown on polar and nonpolar gallium nitride substrates

    Science.gov (United States)

    Lai, Kun-Yu

    Nonpolar (m-plane or a-plane) gallium nitride (GaN) is predicted to be a potential substrate material to improve luminous efficiencies of nitride-based quantum wells (QWs). Numerical calculations indicated that the spontaneous emission rate in a single In0.15Ga0.85N/GaN QW could be improved by ˜2.2 times if the polarization-induced internal field was avoided by epitaxial deposition on nonpolar substrates. A challenge for nonpolar GaN is the limited size (less than 10x10 mm2) of substrates, which was addressed by expansion during the regrowth by Hydride Vapor Phase Epitaxy (HVPE). Subsurface damage in GaN substrates were reduced by annealing with NH3 and N2 at 950°C for 60 minutes. It was additionally found that the variation of m-plane QWs' emission properties was significantly increased when the substrate miscut toward a-axis was increased from 0° to 0.1°. InGaN/GaN QWs were grown by Metalorganic Chemical Vapor Deposition (MOCVD) on c-plane and m-plane GaN substrates. The QWs were studied by cathodoluminescence spectroscopy with different incident electron beam probe currents (0.1 nA ˜ 1000 nA). Lower emission intensities and longer peak wavelengths from c-plane QWs were attributed to the Quantum-confined Stark Effect (QCSE). The emission intensity ratios of m-plane QWs to c-plane QWs decreased from 3.04 at 1 nA to 1.53 at 1000 nA. This was identified as the stronger screening effects of QCSE at higher current densities in c-plane QWs. To further investigate these effects in a fabricated structure, biased photoluminescence measurements were performed on m-plane InGaN/GaN QWs. The purpose was to detect the possible internal fields induced by the dot-like structure in the InGaN layer through the response of these internal fields under externally applied fields. No energy shifts of the QWs were observed, which was attributed to strong surface leakage currents.

  4. Determination of gallium in flint clay by neutron activation analysis

    International Nuclear Information System (INIS)

    Padova, A.; Even, O.

    1975-01-01

    Neutron activation analysis was applied to determine gallium traces in different flint clay samples found in Israel. The principal 835 KeV gamma ray of gallium-72 was measured with a 60 cm 2 Ge(Li) spectrometer in conjunction with a Packard 4000 channel analyzer and Wang table computer, model 720 C. Samples were weighed into polyethylene vials, sealed and inserted into polyethylene rabbit. Gallium metal and gallium oxide used as standards were similarly prepared for irradiation for 10 minutes in the I.R.R.I., at a thermal flux of 3.5x10 12 n/cm 2 sec. Careful calibration of the spectrometer and judicious choice of cooling time eliminate the influence of such elements as europium-152, and sodium-24 and make possible the determination of gallium without prior chemical separation. Representative Israel flint clay samples contain about 55 ppm gallium. (B.G.)

  5. Interactions of Zircaloy cladding with gallium: 1998 midyear status

    International Nuclear Information System (INIS)

    Wilson, D.F.; DiStefano, J.R.; Strizak, J.P.; King, J.F.; Manneschmidt, E.T.

    1998-06-01

    A program has been implemented to evaluate the effect of gallium in mixed-oxide (MOX) fuel derived from weapons-grade (WG) plutonium on Zircaloy cladding performance. The objective is to demonstrate that low levels of gallium will not compromise the performance of the MOX fuel system in a light-water reactor. The graded, four-phase experimental program was designed to evaluate the performance of prototypic Zircaloy cladding materials against (1) liquid gallium (Phase 1), (2) various concentrations of Ga 2 O 3 (Phase 2), (3) centrally heated surrogate fuel pellets with expected levels of gallium (Phase 3), and (4) centrally heated prototypic MOX fuel pellets (Phase 4). This status report describes the results of a series of tests for Phases 1 and 2. Three types of tests are being performed: (1) corrosion, (2) liquid metal embrittlement, and (3) corrosion-mechanical. These tests will determine corrosion mechanisms, thresholds for temperature and concentration of gallium that may delineate behavioral regimes, and changes in the mechanical properties of Zircaloy. Initial results have generally been favorable for the use of WG-MOX fuel. The MOX fuel cladding, Zircaloy, does react with gallium to form intermetallic compounds at ≥300 C; however, this reaction is limited by the mass of gallium and is therefore not expected to be significant with a low level (parts per million) of gallium in the MOX fuel. Although continued migration of gallium into the initially formed intermetallic compound can result in large stresses that may lead to distortion, this was shown to be extremely unlikely because of the low mass of gallium or gallium oxide present and expected clad temperatures below 400 C. Furthermore, no evidence for grain boundary penetration by gallium has been observed

  6. Psoas abscess localization by gallium scan in aplastic anemia

    International Nuclear Information System (INIS)

    Oster, M.W.; Gelrud, L.G.; Lotz, M.J.; Herzig, G.P.; Johnston, G.S.

    1975-01-01

    Gallium 67 scanning is an effective method of detecting inflammatory lesions, especially abscesses. A 10-year-old boy with aplastic anemia and severe leukopenia and granulocytopenia had a psoas abscess diagnosed by gallium scan. The patient died with Candida sepsis 18 days after bone marrow transplantation. At autopsy, a chronic psoas abscess with Candida was found. The gallium scan offers a clinically effective and noninvasive means of evaluating suspected infection in the granulocytopenia patient. (U.S.)

  7. Survey of the market, supply and availability of gallium

    Energy Technology Data Exchange (ETDEWEB)

    Rosi, F.D.

    1980-07-01

    The objective of this study was to assess the present consumption and supply of gallium, its potential availability in the satellite power system (SPS) implementation time frame, and commercial and new processing methods for increasing the production of gallium. Findings are reported in detail. The findings strongly suggest that with proper long range planning adequate gallium would be available from free-enterprise world supplies of bauxite for SPS implementation.

  8. Interactions of zircaloy cladding with gallium -- 1997 status

    International Nuclear Information System (INIS)

    Wilson, D.F.; DiStefano, J.R.; King, J.F.; Manneschmidt, E.T.; Strizak, J.P.

    1997-11-01

    A four phase program has been implemented to evaluate the effect of gallium in mixed oxide (MOX) fuel derived from weapons grade (WG) plutonium on Zircaloy cladding performance. The objective is to demonstrate that low levels of gallium will not compromise the performance of the MOX fuel system in LWR. This graded, four phase experimental program will evaluate the performance of prototypic Zircaloy cladding materials against: (1) liquid gallium (Phase 1), (2) various concentrations of Ga 2 O 3 (Phase 2), (3) centrally heated surrogate fuel pellets with expected levels of gallium (Phase 3), and (4) centrally heated prototypic MOX fuel pellets (Phase 4). This status report describes the results of an initial series of tests for phases 1 and 2. Three types of tests are being performed: (1) corrosion, (2) liquid metal embrittlement (LME), and (3) corrosion mechanical. These tests are designed to determine the corrosion mechanisms, thresholds for temperature and concentration of gallium that may delineate behavioral regimes, and changes in mechanical properties of Zircaloy. Initial results have generally been favorable for the use of WG-MOX fuel. The MOX fuel cladding, Zircaloy, does react with gallium to form intermetallic compounds at ≥ 300 C; however, this reaction is limited by the mass of gallium and is therefore not expected to be significant with a low level (in parts per million) of gallium in the MOX fuel. While continued migration of gallium into the initially formed intermetallic compound results in large stresses that can lead to distortion, this is also highly unlikely because of the low mass of gallium or gallium oxide present and expected clad temperatures below 400 C. Furthermore, no evidence for grain boundary penetration by gallium has been observed

  9. Inflammatory pseudotumor: A gallium-avid mobile mesenteric mass

    International Nuclear Information System (INIS)

    Auringer, S.T.; Scott, M.D.; Sumner, T.E.

    1991-01-01

    An 8-yr-old boy with a 1-mo history of culture-negative fever and anemia underwent gallium, ultrasound, and computed tomography studies as part of the evaluation of a fever of unknown origin. These studies revealed a mobile gallium-avid solid abdominal mass subsequently proven to be an inflammatory pseudotumor of the mesentery, a rare benign mass. This report documents the gallium-avid nature of this rare lesion and discusses associated characteristic clinical, pathologic, and radiographic features

  10. Gallium Nitride Crystals: Novel Supercapacitor Electrode Materials.

    Science.gov (United States)

    Wang, Shouzhi; Zhang, Lei; Sun, Changlong; Shao, Yongliang; Wu, Yongzhong; Lv, Jiaxin; Hao, Xiaopeng

    2016-05-01

    A type of single-crystal gallium nitride mesoporous membrane is fabricated and its supercapacitor properties are demonstrated for the first time. The supercapacitors exhibit high-rate capability, stable cycling life at high rates, and ultrahigh power density. This study may expand the range of crystals as high-performance electrode materials in the field of energy storage. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Gallium-cladding compatibility testing plan. Phases 1 and 2: Test plan for gallium corrosion tests. Revision 2

    International Nuclear Information System (INIS)

    Wilson, D.F.; Morris, R.N.

    1998-05-01

    This test plan is a Level-2 document as defined in the Fissile Materials Disposition Program Light-Water-Reactor Mixed-Oxide Fuel Irradiation Test Project Plan. The plan summarizes and updates the projected Phases 1 and 2 Gallium-Cladding compatibility corrosion testing and the following post-test examination. This work will characterize the reactions and changes, if any, in mechanical properties that occur between Zircaloy clad and gallium or gallium oxide in the temperature range 30--700 C

  12. Boron, phosphorus, and gallium determination in silicon crystals doped with gallium

    International Nuclear Information System (INIS)

    Shklyar, B.L.; Dankovskij, Yu.V.; Trubitsyn, Yu.V.

    1989-01-01

    When studying IR transmission spectra of silicon doped with gallium in the range of concentrations 1 x 10 14 - 5 x 10 16 cm -3 , the possibility to quantity at low (∼ 20 K) temperatures residual impurities of boron and phosphorus is ascertained. The lower determination limit of boron is 1 x 10 12 cm -3 for a sample of 10 nm thick. The level of the impurities in silicon crystals, grown by the Czochralski method and method of crucible-free zone melting, is measured. Values of boron and phosphorus concentrations prior to and after their alloying with gallium are compared

  13. Effect of barrier height on friction behavior of the semiconductors silicon and gallium arsenide in contact with pure metals

    Science.gov (United States)

    Mishina, H.; Buckley, D. H.

    1984-01-01

    Friction experiments were conducted for the semiconductors silicon and gallium arsenide in contact with pure metals. Polycrystalline titanium, tantalum, nickel, palladium, and platinum were made to contact a single crystal silicon (111) surface. Indium, nickel, copper, and silver were made to contact a single crystal gallium arsenide (100) surface. Sliding was conducted both in room air and in a vacuum of 10 to the minus 9th power torr. The friction of semiconductors in contact with metals depended on a Schottky barrier height formed at the metal semiconductor interface. Metals with a higher barrier height on semiconductors gave lower friction. The effect of the barrier height on friction behavior for argon sputtered cleaned surfaces in vacuum was more specific than that for the surfaces containing films in room air. With a silicon surface sliding on titanium, many silicon particles back transferred. In contrast, a large quantity of indium transferred to the gallium arsenide surface.

  14. Study of current instabilities in high resistivity gallium arsenide; Etude des instabilites de courant dans l'arseniure de gallium de haute resistivite

    Energy Technology Data Exchange (ETDEWEB)

    Barraud, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    We have shown the existence and made a study of the current oscillations produced in high-resistivity gallium arsenide by a strong electric field. The oscillations are associated with the slow travelling of a region of high electrical field across the whole sample. An experimental study of the properties of these instabilities has made it possible for us to distinguish this phenomenon from the Gunn effect, from acoustic-electric effects and from contact effects. In order to account for this type of instability, a differential trapping mechanism involving repulsive impurities is proposed; this mechanism can reduce the concentration of charge carriers in the conduction band at strong electrical fields and can lead to the production of a high-field domain. By developing this model qualitatively we have been able to account for all the properties of high-resistance gallium arsenide crystals subjected to a strong electrical field: increase of the Hall constant, existence of a voltage threshold for these oscillations, production of domains of high field, low rate of propagation of these domains, and finally the possibility of inverting the direction of the propagation of the domain without destroying the latter. A quantitative development of the model makes it possible to calculate the various characteristic parameters of these instabilities. Comparison with experiment shows that there is a good agreement, the small deviations coming especially from the lack of knowledge concerning transport properties in gallium arsenide subjected to high fields. From a study of this model, it appears that the instability phenomenon can occur over a wide range of repulsive centre concentrations, and also for a large range of resistivities. This is the reason why it appears systematically in gallium arsenide of medium and high resistivity. (authors) [French] Nous avons mis en evidence et etudie des oscillations de courant qui se produisent a champ electrique eleve dans l'arseniure de

  15. State and prospects of Russian and world gallium market

    Directory of Open Access Journals (Sweden)

    F. D. Larichkin

    2017-12-01

    Full Text Available The authors consider the state of Russian and world mineral and raw materials base of gallium, the main spheres of application in various branches and industries of the national economy. The article presents the generalization and analysis of trends in world and Russian production, consumption of rare metal and its compounds, the world trade and global market of gallium and products based on it, consuming it in new science-intensive innovative industries, including the production of military equipment. The unique chemical properties of gallium remained unclaimed for a long time. Only after the discovery of the semiconductor properties of gallium compounds has the situation radically changed: the rate of growth in production and consumption of metallic gallium at the end of the twentieth and beginning of the 21st century amounted to an average of more than 8% per year. The largest area of consumption of gallium is the production of semiconductor materials – gallium arsenide (GaAs and gallium nitride (GaN. The areas of application of gallium not related to the semiconductor industry are very small. Industry structure of consumption of GaAs and GaN: in integrated circuits is 66%; optoelectronic devices (light-emitting diodes, laser diodes, photodetectors and solar batteries – 20%; the remaining 14% – scientific research, special alloys, etc. Optoelectronic devices are used in aerospace industry, consumer goods, industrial and medical equipment and telecommunications. Integral circuits are used in the military industry, high-power computers and electronic communications. The most significant growing sectors of the market are LEDs, electronics based on gallium nitride and solar cells. Solar energy has become the fastest growing branch of the world economy. The volumes of gallium production in Russia do not correspond to its raw material, scientific and technological potential as the country and require the development activation based on state

  16. Automated realization of the gallium melting and triple points

    Science.gov (United States)

    Yan, X.; Duan, Y.; Zhang, J. T.; Wang, W.

    2013-09-01

    In order to improve the automation and convenience of the process involved in realizing the gallium fixed points, an automated apparatus, based on thermoelectric and heat pipe technologies, was designed and developed. This paper describes the apparatus design and procedures for freezing gallium mantles and realizing gallium melting and triple points. Also, investigations on the melting behavior of a gallium melting point cell and of gallium triple point cells were carried out while controlling the temperature outside the gallium point cells at 30 °C, 30.5 °C, 31 °C, and 31.5 °C. The obtained melting plateau curves show dentate temperature oscillations on the melting plateaus for the gallium point cells when thermal couplings occurred between the outer and inner liquid-solid interfaces. The maximum amplitude of the temperature fluctuations was about 1.5 mK. Therefore, the temperature oscillations can be used to indicate the ending of the equilibrium phase transitions. The duration and amplitude of such temperature oscillations depend on the temperature difference between the setting temperature and the gallium point temperature; the smaller the temperature difference, the longer the duration of both the melting plateaus and the temperature fluctuations.

  17. Indium Gallium Nitride Multijunction Solar Cell Simulation Using Silvaco Atlas

    Science.gov (United States)

    2007-06-01

    models is of great interest in space applications. By increasing the efficiency of photovoltaics, the number of solar panels is decreased. Therefore...obtained in single-junction solar cells by using Gallium Arsenide. Monocrystalline Gallium Arsenide has a maximum efficiency of approximately 25.1% [10

  18. State of rare earth impurities in gallium and indium antimonides

    International Nuclear Information System (INIS)

    Evgen'ev, S.B.; Kuz'micheva, G.M.

    1990-01-01

    State of rare earth impurities in indium and gallium antimonides was studied. Results of measuring density and lattice parameter of samples in GaSb-rare earth and InSb-rare earth systems are presented. It is shown that during rare earth dissolution in indium and gallium antimonides rare earth atoms occupy interstitial positions or, at least, are displaced from lattice points

  19. Thermal Plasma Synthesis of Crystalline Gallium Nitride Nanopowder from Gallium Nitrate Hydrate and Melamine

    Directory of Open Access Journals (Sweden)

    Tae-Hee Kim

    2016-02-01

    Full Text Available Gallium nitride (GaN nanopowder used as a blue fluorescent material was synthesized by using a direct current (DC non-transferred arc plasma. Gallium nitrate hydrate (Ga(NO33∙xH2O was used as a raw material and NH3 gas was used as a nitridation source. Additionally, melamine (C3H6N6 powder was injected into the plasma flame to prevent the oxidation of gallium to gallium oxide (Ga2O3. Argon thermal plasma was applied to synthesize GaN nanopowder. The synthesized GaN nanopowder by thermal plasma has low crystallinity and purity. It was improved to relatively high crystallinity and purity by annealing. The crystallinity is enhanced by the thermal treatment and the purity was increased by the elimination of residual C3H6N6. The combined process of thermal plasma and annealing was appropriate for synthesizing crystalline GaN nanopowder. The annealing process after the plasma synthesis of GaN nanopowder eliminated residual contamination and enhanced the crystallinity of GaN nanopowder. As a result, crystalline GaN nanopowder which has an average particle size of 30 nm was synthesized by the combination of thermal plasma treatment and annealing.

  20. Gallium-containing hydroxyapatite for potential use in orthopedics

    International Nuclear Information System (INIS)

    Melnikov, P.; Teixeira, A.R.; Malzac, A.; Coelho, M. de B.

    2009-01-01

    A novel material that may be recommended for grafts and implants stimulating bone growth has been obtained by introducing gallium ions (up to 11.0 mass%) into crystalline lattice of hydroxyapatite. The doping was carried out using gallium nitrate and sodium gallate solutions. In both cases, lattice parameters of gallium-doped hydroxyapatite are identical to those of pure synthetic hydroxyapatite. Gallium does not replace calcium as a result of heterovalent substitution and consequently produces no distortions in the framework of hydroxyapatite matrix. It remains strongly fixed in the form of solid solution of intercalation. According to scanning electron microscopy images gallium insertion does not cause any morphological alterations in hydroxyapatite structure and the product developed meets physico-chemical criteria for biomaterial to be employed in orthopedic practice and local handling of traumatic injuries. Its future usage opens the opportunity to enhance osteosynthesis and calcium retention in loco.

  1. Study of Magnetohydrodynamic Surface Waves on Liquid Gallium

    Energy Technology Data Exchange (ETDEWEB)

    Hantao Ji; William Fox; David Pace; H.L. Rappaport

    2004-05-13

    Magnetohydrodynamic (MHD) surface waves on liquid gallium are studied theoretically and experimentally in the small magnetic Reynolds number limit. A linear dispersion relation is derived when a horizontal magnetic field and a horizontal electric current is imposed. No wave damping is found in the shallow liquid limit while waves always damp in the deep liquid limit with a magnetic field parallel to the propagation direction. When the magnetic field is weak, waves are weakly damped and the real part of the dispersion is unaffected, while in the opposite limit waves are strongly damped with shortened wavelengths. In a table-top experiment, planar MHD surface waves on liquid gallium are studied in detail in the regime of weak magnetic field and deep liquid. A non-invasive diagnostic accurately measures surface waves at multiple locations by reflecting an array of lasers off the surface onto a screen, which is recorded by an Intensified-CCD camera. The measured dispersion relation is consistent with the linear theory with a reduced surface tension likely due to surface oxidation. In excellent agreement with linear theory, it is observed that surface waves are damped only when a horizontal magnetic field is imposed parallel to the propagation direction. No damping is observed under a perpendicular magnetic field. The existence of strong wave damping even without magnetic field suggests the importance of the surface oxide layer. Implications to the liquid metal wall concept in fusion reactors, especially on the wave damping and a Rayleigh-Taylor instability when the Lorentz force is used to support liquid metal layer against gravity, are discussed.

  2. Study of Magnetohydrodynamic Surface Waves on Liquid Gallium

    International Nuclear Information System (INIS)

    Hantao Ji; William Fox; David Pace; Rappaport, H.L.

    2004-01-01

    Magnetohydrodynamic (MHD) surface waves on liquid gallium are studied theoretically and experimentally in the small magnetic Reynolds number limit. A linear dispersion relation is derived when a horizontal magnetic field and a horizontal electric current is imposed. No wave damping is found in the shallow liquid limit while waves always damp in the deep liquid limit with a magnetic field parallel to the propagation direction. When the magnetic field is weak, waves are weakly damped and the real part of the dispersion is unaffected, while in the opposite limit waves are strongly damped with shortened wavelengths. In a table-top experiment, planar MHD surface waves on liquid gallium are studied in detail in the regime of weak magnetic field and deep liquid. A non-invasive diagnostic accurately measures surface waves at multiple locations by reflecting an array of lasers off the surface onto a screen, which is recorded by an Intensified-CCD camera. The measured dispersion relation is consistent with the linear theory with a reduced surface tension likely due to surface oxidation. In excellent agreement with linear theory, it is observed that surface waves are damped only when a horizontal magnetic field is imposed parallel to the propagation direction. No damping is observed under a perpendicular magnetic field. The existence of strong wave damping even without magnetic field suggests the importance of the surface oxide layer. Implications to the liquid metal wall concept in fusion reactors, especially on the wave damping and a Rayleigh-Taylor instability when the Lorentz force is used to support liquid metal layer against gravity, are discussed

  3. Fluorimetric analysis of gallium in bauxite, by-products, products from gallium processing and its control solutions

    International Nuclear Information System (INIS)

    Ferreira, C.A.M.; Medeiros, V.

    1987-01-01

    The gallium processing since raw material analysis until end-products analysis is studied. Gallium presence in by-products and products, as well as the fluorimetric method is analyzed. Equipments and materials used in laboratory, reagents and chemical solutions are described. (M.J.C.) [pt

  4. Patterned gallium surfaces as molecular mirrors.

    Science.gov (United States)

    Bossi, Alessandra; Rivetti, Claudio; Mangiarotti, Laura; Whitcombe, Michael J; Turner, Anthony P F; Piletsky, Sergey A

    2007-09-30

    An entirely new means of printing molecular information on a planar film, involving casting nanoscale impressions of the template protein molecules in molten gallium, is presented here for the first time. The metallic imprints not only replicate the shape and size of the proteins used as template. They also show specific binding for the template species. Such a simple approach to the creation of antibody-like properties in metallic mirrors can lead to applications in separations, microfluidic devices, and the development of new optical and electronic sensors, and will be of interest to chemists, materials scientists, analytical specialists, and electronic engineers.

  5. Sodium Flux Growth of Bulk Gallium Nitride

    Science.gov (United States)

    Von Dollen, Paul Martin

    This dissertation focused on development of a novel apparatus and techniques for crystal growth of bulk gallium nitride (GaN) using the sodium flux method. Though several methods exist to produce bulk GaN, none have been commercialized on an industrial scale. The sodium flux method offers potentially lower cost production due to relatively mild process conditions while maintaining high crystal quality. But the current equipment and methods for sodium flux growth of bulk GaN are generally not amenable to large-scale crystal growth or in situ investigation of growth processes, which has hampered progress. A key task was to prevent sodium loss or migration from the sodium-gallium growth melt while permitting N2 gas to access the growing crystal, which was accomplished by implementing a reflux condensing stem along with a reusable sealed capsule. The reflux condensing stem also enabled direct monitoring and control of the melt temperature, which has not been previously reported for the sodium flux method. Molybdenum-based materials were identified from a corrosion study as candidates for direct containment of the corrosive sodium-gallium melt. Successful introduction of these materials allowed implementation of a crucible-free containment system, which improved process control and can potentially reduce crystal impurity levels. Using the new growth system, the (0001) Ga face (+c plane) growth rate was >50 mum/hr, which is the highest bulk GaN growth rate reported for the sodium flux method. Omega X-ray rocking curve (?-XRC) measurements indicated the presence of multiple grains, though full width at half maximum (FWHM) values for individual peaks were 1020 atoms/cm3, possibly due to reactor cleaning and handling procedures. This dissertation also introduced an in situ technique to correlate changes in N2 pressure with dissolution of nitrogen and precipitation of GaN from the sodium-gallium melt. Different stages of N2 pressure decay were identified and linked to

  6. Compatibility of ITER candidate structural materials with static gallium

    International Nuclear Information System (INIS)

    Luebbers, P.R.; Michaud, W.F.; Chopra, O.K.

    1993-12-01

    Tests were conducted on the compatibility of gallium with candidate structural materials for the International Thermonuclear Experimental Reactor, e.g., Type 316 SS, Inconel 625, and Nb-5 Mo-1 Zr alloy, as well as Armco iron, Nickel 270, and pure chromium. Type 316 stainless steel is least resistant to corrosion in static gallium and Nb-5 Mo-1 Zr alloy is most resistant. At 400 degrees C, corrosion rates are ∼4.0, 0.5, and 0.03 mm/yr for type 316 SS, Inconel 625, and Nb-5 Mo- 1 Zr alloy, respectively. The pure metals react rapidly with gallium. In contrast to findings in earlier studies, pure iron shows greater corrosion than nickel. The corrosion rates at 400 degrees C are ≥88 and 18 mm/yr, respectively, for Armco iron and Nickel 270. The results indicate that at temperatures up to 400 degrees C, corrosion occurs primarily by dissolution and is accompanied by formation of metal/gallium intermetallic compounds. The solubility data for pure metals and oxygen in gallium are reviewed. The physical, chemical, and radioactive properties of gallium are also presented. The supply and availability of gallium, as well as price predictions through the year 2020, are summarized

  7. Fabrication of Aluminum Gallium Nitride/Gallium Nitride MESFET And It's Applications in Biosensing

    Science.gov (United States)

    Alur, Siddharth

    Gallium Nitride has been researched extensively for the past three decades for its application in Light Emitting Diodes (LED's), power devices and UV photodetectors. With the recent developments in crystal growth technology and the ability to control the doping there has been an increased interest in heterostructures formed between Gallium nitride and it's alloy Aluminium Gallium Nitride. These heterostructures due to the combined effect of spontaneous and piezoelectric effect can form a high density and a high mobility electron gas channel without any intentional doping. This high density electron gas makes these heterostructures ideal to be used as sensors. Gallium Nitride is also chemically very stable. Detection of biomolecules in a fast and reliable manner is very important in the areas of food safety and medical research. For biomolecular detection it is paramount to have a robust binding of the probes on the sensor surface. Therefore, in this dissertation, the fabrication and application of the AlGaN/GaN heterostructures as biological sensors for the detection of DNA and Organophosphate hydrolase enzyme is discussed. In order to use these AlGaN/GaN heterostructures as biological sensors capable of working in a liquid environment photodefinable polydimethyl-siloxane is used as an encapsulant. The immobilization conditions for a robust binding of thiolated DNA and the catalytic receptor enzyme organophosphate hydrolase on gold surfaces is developed with the help of X-ray photoelectron spectroscopy. DNA and OPH are detected by measuring the change in the drain current of the device as a function of time.

  8. Optical Characterization of Thick Growth Orientation-Patterned Gallium Arsenide

    National Research Council Canada - National Science Library

    Meyer, Joshua W

    2006-01-01

    .... Orientation patterned gallium arsenide (OPGaAs) is a promising nonlinear conversion material because it has broad transparency and can be engineered for specific pump laser and output wavelengths using quasi-phase matching techniques...

  9. Fabrication and properties of gallium metallic photonic crystals

    International Nuclear Information System (INIS)

    Kozhevnikov, V.F.; Diwekar, M.; Kamaev, V.P.; Shi, J.; Vardeny, Z.V.

    2003-01-01

    Gallium metallic photonic crystals with 100% filling factor have been fabricated via infiltration of liquid gallium into opals of 300-nm silica spheres using a novel high pressure-high temperature technique. The electrical resistance of the Ga-opal crystals was measured at temperatures from 10 to 280 K. The data obtained show that Ga-opal crystals are metallic network with slightly smaller temperature coefficient of resistivity than that for bulk gallium. Optical reflectivity of bulk gallium, plain opal and several Ga-opal crystals were measured at photon energies from 0.3 to 6 eV. A pronounced photonic stop band in the visible spectral range was found in both the plain and Ga infiltrated opals. The reflectivity spectra also show increase in reflectivity below 0.6 eV; which we interpret as a significantly lower effective plasma frequency of the metallic mesh in the infiltrated opal compare to the plasma frequency in the pure metal

  10. Single and double ionization of gallium by electron impact

    Indian Academy of Sciences (India)

    Electron impact single and double ionization cross sections of gallium have been calcu- ... The experimental data on single ionization have been compared with the empirical and ..... and multiplication sign curve (¢¢¢) represent present.

  11. Multiple scaling power in liquid gallium under pressure conditions

    Energy Technology Data Exchange (ETDEWEB)

    Li, Renfeng; Wang, Luhong; Li, Liangliang; Yu, Tony; Zhao, Haiyan; Chapman, Karena W.; Rivers, Mark L.; Chupas, Peter J.; Mao, Ho-kwang; Liu, Haozhe

    2017-06-01

    Generally, a single scaling exponent, Df, can characterize the fractal structures of metallic glasses according to the scaling power law. However, when the scaling power law is applied to liquid gallium upon compression, the results show multiple scaling exponents and the values are beyond 3 within the first four coordination spheres in real space, indicating that the power law fails to describe the fractal feature in liquid gallium. The increase in the first coordination number with pressure leads to the fact that first coordination spheres at different pressures are not similar to each other in a geometrical sense. This multiple scaling power behavior is confined within a correlation length of ξ ≈ 14–15 Å at applied pressure according to decay of G(r) in liquid gallium. Beyond this length the liquid gallium system could roughly be viewed as homogeneous, as indicated by the scaling exponent, Ds, which is close to 3 beyond the first four coordination spheres.

  12. Compatibility of candidate structural materials with static gallium

    International Nuclear Information System (INIS)

    Luebbers, P.R.; Michaud, W.F.; Chopra, O.K.

    1993-01-01

    Scoping tests were conducted on compatibility of gallium with candidate structural materials, e.g., Type 316 SS, Inconel 625, and Nb-5 Mo-1 Zr alloy, as well as Armco iron, Nickel 270, and pure chronimum. Type 316 stainless steel is least resistant and Nb-5 Mo-1 Zr alloy is most resistant to corrosion in static gallium. At 400 degrees C, corrosion rates are ∼4.0, 0.5, and 0.03 mm/y for Type 316 SS, Inconel 625, and Nb-5 Mo-1 Zr alloy, respectively. The pure metals react rapidly with gallium. In contrast to findings in earlier studies, pure iron shows greater corrosion than does nickel. The corrosion rates at 400 degrees C are ≥90 and 17 mm/y, respectively, for Armco iron and Nickel 270. The results indicate that at temperatures up to 400 degrees C, corrosion occurs primarily by dissolution accompanied by formation of metal/gallium intermetallic compounds

  13. Gallium accumulation in early pulmonary Pneumocystis carinii infection

    International Nuclear Information System (INIS)

    Stevens, D.A.; Allegra, J.C.

    1986-01-01

    The accumulation of gallium 67 citrate in pulmonary Pneumocystis carinii is well known. The sensitivity of gallium uptake in detecting early inflammatory processes, even when conventional roentgenograms are normal, would seem to make it possible in immunocompromised patients to make a presumptive diagnosis of this serious infection early in its course without using invasive techniques to demonstrate the organism. However, the presence of gallium uptake in radiation pneumonitis, pulmonary drug toxicity, and other processes that also occur in this group limit its usefulness. In our two patients--a young woman with Hodgkin's disease and an elderly woman with small cell lung cancer--this technique proved helpful. Although the latter patient was successfully treated empirically, such empiric treatment should be reserved for patients unable or unwilling to undergo invasive tests. Pulmonary gallium uptake in patients with respiratory symptoms, even with a normal chest film, should prompt attempts to directly demonstrate the organism

  14. Gallium 67 scintigraphic examination of dilated myocardiopathies

    International Nuclear Information System (INIS)

    Lanfranchi, J.; Sachs, R.N.; Beaudet, B.; Deblock, C.; Tellier, P.

    1989-01-01

    Twenty-seven patients were diagnosed as having dilated cardiomyopathies, based on increases in the cardiothoracic index > 0.50, in the diastolic and systolic diameters of the left ventricle, and in the telediastolic volume of the left ventricle, which was indexed by body surface determined by contrast ventriculography. They underwent gallium 67 scintigraphic examination of the myocardium, in order to non-invasively detect the presence of an inflammatory infiltrate. Fifteen of them also had endomyocardial biopsies and all had virology check-up. The results were disappointing. Only in one case was the scintigraphic image undeniably positive; in 20 other patients the findings were dubious or negative. This technique did not demonstrate the presence of an inflammatory infiltrate and thus an association between myocarditis and dilated cardiomyopathy, could not be established [fr

  15. Cavity optomechanics in gallium phosphide microdisks

    International Nuclear Information System (INIS)

    Mitchell, Matthew; Barclay, Paul E.; Hryciw, Aaron C.

    2014-01-01

    We demonstrate gallium phosphide (GaP) microdisk optical cavities with intrinsic quality factors >2.8 × 10 5 and mode volumes 3 , and study their nonlinear and optomechanical properties. For optical intensities up to 8.0 × 10 4 intracavity photons, we observe optical loss in the microcavity to decrease with increasing intensity, indicating that saturable absorption sites are present in the GaP material, and that two-photon absorption is not significant. We observe optomechanical coupling between optical modes of the microdisk around 1.5 μm and several mechanical resonances, and measure an optical spring effect consistent with a theoretically predicted optomechanical coupling rate g 0 /2π∼30 kHz for the fundamental mechanical radial breathing mode at 488 MHz

  16. Gallium Nitride Schottky betavoltaic nuclear batteries

    International Nuclear Information System (INIS)

    Lu Min; Zhang Guoguang; Fu Kai; Yu Guohao; Su Dan; Hu Jifeng

    2011-01-01

    Research highlights: → Gallium Nitride nuclear batteries with Ni-63 are demonstrated for the first time. → Open circuit voltage of 0.1 V and conversion efficiency of 0.32% have been obtained. → The limited performance is due to thin effective energy deposition layer. → The output power is expected to greatly increase with growing thick GaN films. -- Abstract: Gallium Nitride (GaN) Schottky betavoltaic nuclear batteries (GNBB) are demonstrated in our work for the first time. GaN films are grown on sapphire substrates by metalorganic chemical vapor deposition (MOCVD), and then GaN Schottky diodes are fabricated by normal micro-fabrication process. Nickel with mass number of 63 ( 63 Ni), which emits β particles, is loaded on the GaN Schottky diodes to achieve GNBB. X-ray diffraction (XRD) and photoluminescence (PL) are carried out to investigate the crystal quality for the GaN films as grown. Current-voltage (I-V) characteristics shows that the GaN Schottky diodes are not jet broken down at -200 V due to consummate fabrication processes, and the open circuit voltage of the GNBB is 0.1 V and the short circuit current density is 1.2 nA cm -2 . The limited performance of the GNBB is due to thin effective energy deposition layer, which is only 206 nm to absorb very small partial energy of the β particles because of the relatively high dislocation density and carrier concentration. However, the conversion efficiency of 0.32% and charge collection efficiency (CCE) of 29% for the GNBB have been obtained. Therefore, the output power of the GNBB are expected to greatly increase with growing high quality thick GaN films.

  17. Inhalation developmental toxicology studies: Gallium arsenide in mice and rats

    Energy Technology Data Exchange (ETDEWEB)

    Mast, T.J.; Greenspan, B.J.; Dill, J.A.; Stoney, K.H.; Evanoff, J.J.; Rommereim, R.L.

    1990-12-01

    Gallium arsenide is a crystalline compound used extensively in the semiconductor industry. Workers preparing solar cells and gallium arsenide ingots and wafers are potentially at risk from the inhalation of gallium arsenide dust. The potential for gallium arsenide to cause developmental toxicity was assessed in Sprague- Dawley rats and CD-1 (Swiss) mice exposed to 0, 10, 37, or 75 mg/m{sup 3} gallium arsenide, 6 h/day, 7 days/week. Each of the four treatment groups consisted of 10 virgin females (for comparison), and {approx}30 positively mated rats or {approx}24 positively mated mice. Mice were exposed on 4--17 days of gestation (dg), and rats on 4--19 dg. The day of plug or sperm detection was designated as 0 dg. Body weights were obtained throughout the study period, and uterine and fetal body weights were obtained at sacrifice (rats, 20 dg; mice, 18 dg). Implants were enumerated and their status recorded. Live fetuses were sexed and examined for gross, visceral, skeletal, and soft-tissue craniofacial defects. Gallium and arsenic concentrations were determined in the maternal blood and uterine contents of the rats (3/group) at 7, 14, and 20 dg. 37 refs., 11 figs., 30 tabs.

  18. Recovery of gallium from coal fly ash by a dual reactive extraction process

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, B.; Pazos, C.; Coca, J. [University of Oviedo, Oviedo (Spain). Dept. of Chemical Engineering and Environmental Technology

    1997-08-01

    This paper describes the extraction of gallium from coal fly ash by leaching and extraction with commercial extractants Amerlite LA-2 and LIX-54N dissolved in kerosene. Leaching of gallium and other metals from the fly ash was carried out with 6 M hydrochloric acid. The leaching liquor is first contacted with Amerlite LA-2 which extracts the gallium and iron. The iron is then precipitated with sodium hydroxide, while gallium remains in solution. Gallium is extracted selectively from the base solution with LIX 54; the resulting stripped solution contains 83% of the gallium present in the leaching liquor.

  19. Gallium isotope fractionation during Ga adsorption on calcite and goethite

    Science.gov (United States)

    Yuan, Wei; Saldi, Giuseppe D.; Chen, JiuBin; Vetuschi Zuccolini, Marino; Birck, Jean-Louis; Liu, Yujie; Schott, Jacques

    2018-02-01

    Gallium (Ga) isotopic fractionation during its adsorption on calcite and goethite was investigated at 20 °C as a function of the solution pH, Ga aqueous concentration and speciation, and the solid to solution ratio. In all experiments Ga was found to be enriched in light isotopes at the solid surface with isotope fractionation △71Gasolid-solution up to -1.27‰ and -0.89‰ for calcite and goethite, respectively. Comparison of Ga isotopic data of this study with predictions for 'closed system' equilibrium and 'Rayleigh fractionation' models indicates that the experimental data are consistent with a 'closed system' equilibrium exchange between the fluid and the solid. The results of this study can be interpreted based on Ga aqueous speciation and the structure of Ga complexes formed at the solid surfaces. For calcite, Ga isotope fractionation is mainly triggered by increased Ga coordination and Ga-O bond length, which vary respectively from 4 and 1.84 Å in Ga(OH)4- to 6 and 1.94 Å in the >Ca-O-GaOH(OH2)4+ surface complex. For goethite, despite the formation of Ga hexa-coordinated >FeOGa(OH)20 surface complexes (Ga-O distances of 1.96-1.98 Å) both at acid and alkaline pH, a similar extent of isotope fractionation was found at acid and alkaline pH, suggesting that Ga(OH)4- is preferentially adsorbed on goethite for all investigated pH conditions. In addition, the observed decrease of Ga isotope fractionation magnitude observed with increasing Ga surface coverage for both calcite and goethite is likely related to the formation of Ga surface polymers and/or hydroxides with reduced Ga-O distances. This first study of Ga isotope fractionation during solid-fluid interactions suggests that the adsorption of Ga by oxides, carbonates or clay minerals could yield significant Ga isotope fractionation between secondary minerals and surficial fluids including seawater. Ga isotopes thus should help to better characterize the surficial biogeochemical cycles of gallium and its

  20. Hilar accumulation of gallium-67 in patients with normal chest radiographs

    International Nuclear Information System (INIS)

    Hoshi, Hiroaki; Yamada, Hiroki; Kawahira, Kozaburo; Watanabe, Katsushi

    1982-01-01

    Gallium-67 scintigraphy is a useful screening test to detect malignant or inflammatory lesions. However, the accumulations of Gallium-67 in the normal pulmonary hilum are found in some cases. So, 277 cases with Gallium-67 scintigraphy were discussed. The hilar accumulation of Gallium-67 was classified into four grades, namely Grade 0: no Gallium-67 uptake, Grade I: low Gallium-67 uptake, Grade II: moderate Gallium-67 uptake, and Grade III: high Gallium-67 uptake. Gallium-67 uptake was found in 38 of 277 cases (14%). Thirty cases of these were estimated as Grade I (79%). Cases with Grade II were 20.3%, and only two cases were Grade III (0.7%). Gallium-67 accumulation, was bilateral in 28 cases out of 38 and cases with Gallium-67 accumulation increased with age. Twenty five of the 38 cases with Gallium-67 accumulation had such findings as suggesting old pulmonary inflammation though they had no symptoms of respiratory diseases. This study suggests that hilar Gallium-67 accumulation has no correlation with the active inflammation of the lymphnodes. (author)

  1. Role of Gallium and labeled leukocyte scintigraphy in AIDS patient

    International Nuclear Information System (INIS)

    Palestro, C.J.; Goldsmith, S.J.

    1995-01-01

    Because AIDS patients frequently present with minimal symptomatology, radionuclide imaging with its ability to survey the entire body, is especially valuable. Gallium-67 citrate, the most commonly performed radionuclide study for localizing infection in these patients, is most useful for detecting opportunistic infections, especially in the thorax. A negative gallium scan, particularly when the chest X-ray is unremarkable, rules strongly against pulmonary disease. A negative gallium scan in a patient with an abnormal chest X-ray and Kaposi's sarcoma, suggests that the patient's respiratory distress is related to the neoplasm. Diffuse pulmonary parenchymal uptake of gallium in the HIV (+) patient is most often associated with PCP. While there are other causes of diffuse pulmonary uptake, the more intense or heterogeneous the uptake, the more likely the patient is to have PCP. Focal pulmonary uptake is usually associated with bacterial pneumonia although PCP may occasionally present in this fashion. Lymph node uptake of gallium is usually associated with Mycob acterium avium complex, tuberculosis, or Iymphoma. When corresponding abnormalities are present on thallium scintigraphy lymphoma is likely. Gallium positive, thallium negative, studies suggest mycobacterial disease. Labeled leukocyte imaging is not useful for detecting opportunistic infections probably because of the inflammatory response incited by these organisms. Leukocyte imaging is, however, more sensitive for detecting bacterial pneumonia. In the abdomen, gallium imaging is most useful for identifying lymphadenopathy, while labeled leukocyte imaging is superior for detecting AlDS-associated colitides. In summary, radionuclide studies are valuable diagnostic modalities in AIDS. Their success can be maximized by tailoring the study to the individual's needs

  2. Study of the stability of the gallium isotopes beyond the N = 50 neutron shell closure

    CERN Multimedia

    We propose to study the stability of the nuclear structure beyond N = 50 and Z = 28 with beams of neutron-rich gallium isotopes at the CRIS experiment at ISOLDE. The study of their hyperne structure and isotope shift will provide spins, magnetic dipole moments, electric quadrupole moments and changes in the mean-square charge radii. The $\\beta$-decay of $^{80}$Ga will be unambiguously measured using the technique of Laser Assisted Nuclear Decay Spectroscopy (LANDS). The half-lives of the very neutron-rich isotopes with N > 54 will be measured for their impact on the astrophysical ${r}$-process.

  3. Gallium a unique anti-resorptive agent in bone: Preclinical studies on its mechanisms of action

    International Nuclear Information System (INIS)

    Bockman, R.; Adelman, R.; Donnelly, R.; Brody, L.; Warrell, R.; Jones, K.W.

    1990-01-01

    The discovery of gallium as a new and unique agent for the treatment of metabolic bone disorders was in part fortuitous. Gallium is an exciting new therapeutic agent for the treatment of pathologic states characterized by accelerated bone resorption. Compared to other therapeutic metal compounds containing platinum or germanium, gallium affects its antiresorptive action without any evidence of a cytotoxic effect on bone cells. Gallium is unique amongst all therapeutically available antiresorptive agents in that it favors bone formation. 18 refs., 1 fig

  4. Realization of the Gallium Triple Point at NMIJ/AIST

    Science.gov (United States)

    Nakano, T.; Tamura, O.; Sakurai, H.

    2008-02-01

    The triple point of gallium has been realized by a calorimetric method using capsule-type standard platinum resistance thermometers (CSPRTs) and a small glass cell containing about 97 mmol (6.8 g) of gallium with a nominal purity of 99.99999%. The melting curve shows a very flat and relatively linear dependence on 1/ F in the region from 1/ F = 1 to 1/ F = 20 with a narrow width of the melting curve within 0.1 mK. Also, a large gallium triple-point cell was fabricated for the calibration of client-owned CSPRTs. The gallium triple-point cell consists of a PTFE crucible and a PTFE cap with a re-entrant well and a small vent. The PTFE cell contains 780 g of gallium from the same source as used for the small glass cell. The PTFE cell is completely covered by a stainless-steel jacket with a valve to enable evacuation of the cell. The melting curve of the large cell shows a flat plateau that remains within 0.03 mK over 10 days and that is reproducible within 0.05 mK over 8 months. The calibrated value of a CSPRT obtained using the large cell agrees with that obtained using the small glass cell within the uncertainties of the calibrations.

  5. Rutherford backscatter measurements on tellurium and cadmium implanted gallium arsenide

    International Nuclear Information System (INIS)

    Bell, E.C.

    1979-10-01

    The primary aim of the work described in this thesis was to examine implanted layers of the dopant impurities cadmium and tellurium in gallium arsenide and to experimentally assess their potential for producing electrically active layers. 1.5 MeV Rutherford backscattering measurements of lattice disorder and atom site location have been used to assess post implantation thermal annealing and elevated temperature implantations to site the dopant impurities on either gallium or arsenic lattice positions in an otherwise undisordered lattice. Pyrolitically deposited silicon dioxide was used as an encapsulant to prevent thermal dissociation of the gallium arsenide during annealing. It has been shown that high doses of cadmium and tellurium can be implanted without forming amorphous lattice disorder by heating the gallium arsenide during implantation to relatively low temperatures. Atom site location measurements have shown that a large fraction of a tellurium dose implanted at 180 0 C is located on or near lattice sites. Channeled backscatter measurements have shown that there is residual disorder or lattice strain in gallium arsenide implanted at elevated temperatures. The extent of this disorder has been shown to depend on the implanted dose and implantation temperature. The channeling effect has been used to measure annealing of the disorder. (author)

  6. Gallium scintigraphy in a case of septic cavernous sinus thrombosis

    International Nuclear Information System (INIS)

    Palestro, C.J.; Malat, J.; Gladstone, A.G.; Richman, A.H.

    1986-01-01

    Septic cavernous sinus thrombosis, a relatively uncommon disease entity, frequently can be fatal. Early diagnosis is imperative in order that appropriate treatment be instituted. A 59-year-old woman who was admitted to our institution with complaints of diplopia, blurred vision and fevers that developed following a tooth extraction is presented. Initial CT and lumbar puncture on the day of admission were totally normal. A repeat CT performed 48 hours after admission, on the same day as gallium imaging, demonstrated findings consistent with cavernous sinus thrombosis. Gallium imaging demonstrated intense uptake in the left cavernous sinus and left orbit as well as moderately increased activity in the right cavernous sinus and orbit, confirming infection. The patient was treated with antibiotics, and repeat CT and gallium imaging were performed ten days later, both of which demonstrated near total resolution of the disease process. Conceivably, if gallium imaging had been initiated on the day of admission it may have been the first study to demonstrate an infectious process in the cavernous sinus. Gallium imaging should be considered as a diagnostic tool in the noninvasive workup of this entity

  7. The role of gallium-67 scanning in febrile patients

    International Nuclear Information System (INIS)

    Mouratidis, B.; Lomas, F.

    1994-01-01

    The source of sepsis in febrile patients can be a difficult diagnostic problem. Gallium-67 has been utilized as a diagnostic tool in the evaluation of these patients. A retrospective review was done of 47 patients who presented with pyrexia of unknown origin (27 patients), postoperative fever (11 patients), septicaemia (4 patients) and miscellaneous sepsis (5 patients). Whole body imaging with Gallium-67 gave an overall sensitivity and specificity of 86 and 77%, respectively, which compares favourably with previous studies. The sensitivity and specificity was similar in all patient subgroups. Gallium-67 allowed for more effective and directed use of organ-specific imaging modalities, such as computed tomography, ultrasound and guided intervention, in localizing and defining the source of sepsis. Where more than one possible source of fever was present, Gallium-67 scanning correctly identified the activity of the different foci. Gallium-67 scanning should be used early in the evaluation of patients presenting with fever of uncertain origin. 9 refs., 5 tabs., 2 figs

  8. Gallium nitride at the millennial transition

    International Nuclear Information System (INIS)

    Pankovo, J.I.

    2000-01-01

    The properties of gallium nitride were uncovered in the early years of exploratory research and endowed with negative electron affinity that could be used to make efficient cold cathodes and even dynodes for electron multipliers. GaN has another property i.e. polar nature of the crystal which makes this material piezo-electric and has non-linear optical properties. The piezo-electric properties led to new piezo electric effect may cause interfacial charge. The non-uniform distribution of acceptors, there is also presence of threading and other dislocation in GaN. Defects reappear where two adjacent overgrowth merge, but the good lateral overgrow region is large enough to make lasers. Injection lasers benefit from strong electrical and optical environment. This was achieved by using quantum wells of InGaN in GaN and this can be doped with rare earth elements to exploit the atomic transition between core levels in these elements. The emission efficiency of electrically excited Er in GaN is nearly temperature incentive from 80K to room temperature. An other application of GaN is as a heterojunction emitter for a bi-polar transistor (HBT) that can operate at high temperatures. (A.B.)

  9. Investigation on gallium ions impacting monolayer graphene

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Xin; Zhao, Haiyan, E-mail: hyzhao@tsinghua.edu.cn; Yan, Dong; Pei, Jiayun [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, P. R. Chinaand Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China)

    2015-06-15

    In this paper, the physical phenomena of gallium (Ga{sup +}) ion impacting monolayer graphene in the nanosculpting process are investigated experimentally, and the mechanisms are explained by using Monte Carlo (MC) and molecular dynamics (MD) simulations. Firstly, the MC method is employed to clarify the phenomena happened to the monolayer graphene target under Ga{sup +} ion irradiation. It is found that substrate has strong influence on the damage mode of graphene. The mean sputtering yield of graphene under 30 keV Ga{sup +} ion irradiation is 1.77 and the least ion dose to completely remove carbon atoms in graphene is 21.6 ion/nm{sup 2}. Afterwards, the focused ion beam over 21.6 ion/nm{sup 2} is used for the irradiation on a monolayer graphene supported by SiO2 experimentally, resulting in the nanostructures, i.e., nanodot and nanowire array on the graphene. The performances of the nanostructures are characterized by atomic force microscopy and Raman spectrum. A plasma plume shielding model is put forward to explain the nanosculpting results of graphene under different irradiation parameters. In addition, two damage mechanisms are found existing in the fabrication process of the nanostructures by using empirical MD simulations. The results can help us open the possibilities for better control of nanocarbon devices.

  10. Gallium-based avalanche photodiode optical crosstalk

    International Nuclear Information System (INIS)

    Blazej, Josef; Prochazka, Ivan; Hamal, Karel; Sopko, Bruno; Chren, Dominik

    2006-01-01

    Solid-state single photon detectors based on avalanche photodiode are getting more attention in various areas of applied physics: optical sensors, quantum key distribution, optical ranging and Lidar, time-resolved spectroscopy, X-ray laser diagnostics, and turbid media imaging. Avalanche photodiodes specifically designed for single photon counting semiconductor avalanche structures have been developed on the basis of various materials: Si, Ge, GaP, GaAsP, and InGaP/InGaAs at the Czech Technical University in Prague during the last 20 years. They have been tailored for numerous applications. Trends in demand are focused on detection array construction recently. Even extremely small arrays containing a few cells are of great importance for users. Electrical crosstalk between individual gating and quenching circuits and optical crosstalk between individual detecting cells are serious limitation for array design and performance. Optical crosstalk is caused by the parasitic light emission of the avalanche which accompanies the photon detection process. We have studied in detail the optical emission of the avalanche photon counting structure in the silicon- and gallium-based photodiodes. The timing properties and spectral distribution of the emitted light have been measured for different operating conditions to quantify optical crosstalk. We conclude that optical crosstalk is an inherent property of avalanche photodiode operated in Geiger mode. The only way to minimize optical crosstalk in avalanche photodiode array is to build active quenching circuit with minimum response time

  11. Maskless proton beam writing in gallium arsenide

    Energy Technology Data Exchange (ETDEWEB)

    Mistry, P. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom) and Nano-Electronics Centre, Advanced Technology Institute, University of Surrey, Guildford GU2 7XH (United Kingdom)]. E-mail: p.mistry@surrey.ac.uk; Gomez-Morilla, I. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Smith, R.C. [Nano-Electronics Centre, Advanced Technology Institute, University of Surrey, Guildford GU2 7XH (United Kingdom); Thomson, D. [Advanced Technology Institute, University of Surrey, Guildford GU2 7XH (United Kingdom); Grime, G.W. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Webb, R.P. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Gwilliam, R. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Jeynes, C. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Cansell, A. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Merchant, M. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Kirkby, K.J. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2007-07-15

    Proton beam writing (PBW) is a direct write technique that employs a focused MeV proton beam which is scanned in a pre-determined pattern over a target material which is subsequently electrochemically etched or chemically developed. By changing the energy of the protons the range of the protons can be changed. The ultimate depth of the structure is determined by the range of the protons in the material and this allows structures to be formed to different depths. PBW has been successfully employed on etchable glasses, polymers and semiconductor materials such as silicon (Si) and gallium arsenide (GaAs). This study reports on PBW in p-type GaAs and compares experimental results with computer simulations using the Atlas (copy right) semiconductor device package from SILVACO. It has already been proven that hole transport is required for the electrochemical etching of GaAs using Tiron (4,5-dihydroxy-m-benzenedisulfonic acid, di-sodium salt). PBW in GaAs results in carrier removal in the irradiated regions and consequently minimal hole transport (in these regions) during electrochemical etching. As a result the irradiated regions are significantly more etch resistant than the non-irradiated regions. This allows high aspect ratio structures to be formed.

  12. Maskless proton beam writing in gallium arsenide

    International Nuclear Information System (INIS)

    Mistry, P.; Gomez-Morilla, I.; Smith, R.C.; Thomson, D.; Grime, G.W.; Webb, R.P.; Gwilliam, R.; Jeynes, C.; Cansell, A.; Merchant, M.; Kirkby, K.J.

    2007-01-01

    Proton beam writing (PBW) is a direct write technique that employs a focused MeV proton beam which is scanned in a pre-determined pattern over a target material which is subsequently electrochemically etched or chemically developed. By changing the energy of the protons the range of the protons can be changed. The ultimate depth of the structure is determined by the range of the protons in the material and this allows structures to be formed to different depths. PBW has been successfully employed on etchable glasses, polymers and semiconductor materials such as silicon (Si) and gallium arsenide (GaAs). This study reports on PBW in p-type GaAs and compares experimental results with computer simulations using the Atlas (copy right) semiconductor device package from SILVACO. It has already been proven that hole transport is required for the electrochemical etching of GaAs using Tiron (4,5-dihydroxy-m-benzenedisulfonic acid, di-sodium salt). PBW in GaAs results in carrier removal in the irradiated regions and consequently minimal hole transport (in these regions) during electrochemical etching. As a result the irradiated regions are significantly more etch resistant than the non-irradiated regions. This allows high aspect ratio structures to be formed

  13. Diagnosis of abdominal abscesses with 67gallium

    International Nuclear Information System (INIS)

    Noguera, E.C.; Mothe, G.A.

    1987-01-01

    Twenty six patients were studied with 67 Gallium to detect and localize the site of intra-abdominal and intraperitoneal infection. They were divided in two groups: a) with and b) without physical symptoms that could localize an abcess in the abdominal cavity. All the patients with suppuration had persistent up-take of 67 Ga in one anatomic area of the abdomen, subsequently documented by computarized axial tomography (CAT) in 58% of the cases or by laparotomy in 88% of them. Scintigraphy with 67 Ga in the patients with recent surgery not only detected focal infection in 67% of the cases but excluded subphernic collection. In 78% of patients with prolonged fever, the infection was localized. There was no false positive result. The comparison in 56% of the cases with CAT demonstrated that both techniques are 100% sensitive for the diagnosis of abdominal suppurative processes. Three of the 26 patients, after six weeks of medical treatment, were restudied with 67 Ga and CAT, showing total resolution of their previous abnormalities. It is concluded that 67 Ga scintigraphy performed as the first study in febrile patients independent of the presence or absence of physical symptoms that could localize the abdominal infection, is sensitive for the detection and localization of an abdominal abscess and that a negative result excludes it. (Author) [es

  14. Biological mechanisms of gallium-67 tumor deposition

    International Nuclear Information System (INIS)

    Okuyama, Shinichi; Takeda, Shumpei; Sato, Tachio; Takusagawa, Kimihiko; Awano, Takayuki.

    1979-01-01

    This investigation was undertaken in order to clarify the tumor deposition mechanisms of 67 Ga citrate, a ''universal tumor labeler''. An interspecies comparison of various tumors in the rat and mouse indicated that its highest deposition was in the undifferentiated cell type. Amongst the siblings of experimental tumors, cellular membrane negative charge is greater in the free-cell types than the island-formers: a short-term labeling study revealed a greater 67 Ga deposition in the free-cell types. A subcellar fractionation showed an initial association of 67 Ga with the nuclear and membrane fractions, and a later transition to the lysosomal. Hypotonic lysis revealed a paralleled release of 67 Ga and lysosomal key enzymes. Morphological abnormality of the cancer lysosomes was thought to agree with their Ga retention. This property was clinically confirmed by a scintiscoring technique. Treatment with cold gallium of tumors modified the biological parameters of tumor growth: in vitro it suppressed cell proliferation, reduced saturation density; and produced cellular pleomorphism. In vivo it increased tumor consistency by reducing central necrosis and increasing the viable cell layer thickness. Thus, 67 Ga deposition is closely related to various biological parameters of malignancy including the cellular membrane negative charge as cancer is a membrane disorder, and the lysosomal morphology and function. (author)

  15. Liquid gallium jet-plasma interaction studies in ISTTOK tokamak

    International Nuclear Information System (INIS)

    Gomes, R.B.; Fernandes, H.; Silva, C.; Sarakovskis, A.; Pereira, T.; Figueiredo, J.; Carvalho, B.; Soares, A.; Duarte, P.; Varandas, C.; Lielausis, O.; Klyukin, A.; Platacis, E.; Tale, I.; Alekseyv, A.

    2009-01-01

    Liquid metals have been pointed out as a suitable solution to solve problems related to the use of solid walls submitted to high power loads allowing, simultaneously, an efficient heat exhaustion process from fusion devices. The most promising candidate materials are lithium and gallium. However, lithium has a short liquid state temperature range when compared with gallium. To explore further this property, ISTTOK tokamak is being used to test the interaction of a free flying liquid gallium jet with the plasma. ISTTOK has been successfully operated with this jet without noticeable discharge degradation and no severe effect on the main plasma parameters or a significant plasma contamination by liquid metal. Additionally the response of an infrared sensor, intended to measure the jet surface temperature increase during its interaction with the plasma, has been studied. The jet power extraction capability is extrapolated from the heat flux profiles measured in ISTTOK plasmas.

  16. Gallium-67 imaging with low collimators and energy weighted acquisition

    International Nuclear Information System (INIS)

    Hamill, J.J.; DeVito, R.P.

    1990-01-01

    This paper reports that the medium and high energy collimators used in 67 Ga imaging have poorer resolution than low-energy collimators, such as the LEAP. The low energy collimators could be used for gallium imaging if the background under the 93 and 185 keV peaks could be reduced without degrading the signal-to-noise ratio unacceptably. energy weighted acquisition provides a means of accomplishing this background reduction. The authors have developed weighing functions for gallium imaging through LEAP and high resolution collimators. The resolution of the low energy collimators is realized while the background is comparable to, or better than, the background in normal, energy-window imaging with the medium energy collimator. The pixel noise is somewhat greater than the Poisson noise in normal gallium imaging, and some noise correlations, or noise texture, is introduced

  17. Gallium scan in recurrent Hodgkin's disease in children

    International Nuclear Information System (INIS)

    Yeh, S.D.; Benua, R.S.; Tan, C.T.

    1979-01-01

    In 18 of 88 children with biopsy proven and previously untreated Hodgkin's disease, recurrence developed during a period from four to 53 months after therapy (median period, 22 months). In 16 patients in whom gallium scans were performed, 21 positive gallium scans were obtained during 26 episodes of recurrence. Abnormalities were noted in half of them during a period from one to 10 months prior to physical, laboratory, radiographic or histologic confirmation of recurrence (median period about 5 months). We have concluded that the gallium scan is very useful in initial workup and is sensitive in detecting early recurrence in children with Hodgkin's disease. Such scans are indicated when there is clinical suspicion of recurrence, when other modalities are unavailable or when the results of other studies are equivocal

  18. Gallium-67 scanning in patients with malignant pleural mesothelioma

    International Nuclear Information System (INIS)

    Nakano, Takashi; Maeda, Juichiro; Iwahashi, Noriaki; Tamura, Shinsuke; Hada, Toshikazu; Higashino, Kazuya

    1990-01-01

    The findings of gallium-67 scans in eleven patients with malignant pleural mesothelioma were reviewed and compared to those of chest CT findings. All patients had an abnormal thoracic Ga-67 accumulation. Six out of 11 showed a diffuse accumulation over the entire involved hemithorax and a localized uptake was shown in 5. A marked diffuse thickening of pleura in the absence of adequate gallium accumulation was observed in one patient. Two out of 11 had a reduction of gallium uptake after having combination chemotherapy. These results suggest that a diffusely increased uptake over the entire involved hemithorax is the most characteristic finding of Ga-67 scan in malignant pleural mesothelioma, and that Ga-67 scans may be helpful as a valuable indicator of the proper therapy. However, the superiority of Ga-67 scan to thoracic CT as a means of determining the extent of disease process could not be verified. (author)

  19. Layer-by-layer composition and structure of silicon subjected to combined gallium and nitrogen ion implantation for the ion synthesis of gallium nitride

    Energy Technology Data Exchange (ETDEWEB)

    Korolev, D. S.; Mikhaylov, A. N.; Belov, A. I.; Vasiliev, V. K.; Guseinov, D. V.; Okulich, E. V. [Nizhny Novgorod State University (Russian Federation); Shemukhin, A. A. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation); Surodin, S. I.; Nikolitchev, D. E.; Nezhdanov, A. V.; Pirogov, A. V.; Pavlov, D. A.; Tetelbaum, D. I., E-mail: tetelbaum@phys.unn.ru [Nizhny Novgorod State University (Russian Federation)

    2016-02-15

    The composition and structure of silicon surface layers subjected to combined gallium and nitrogen ion implantation with subsequent annealing have been studied by the X-ray photoelectron spectroscopy, Rutherford backscattering, electron spin resonance, Raman spectroscopy, and transmission electron microscopy techniques. A slight redistribution of the implanted atoms before annealing and their substantial migration towards the surface during annealing depending on the sequence of implantations are observed. It is found that about 2% of atoms of the implanted layer are replaced with gallium bonded to nitrogen; however, it is impossible to detect the gallium-nitride phase. At the same time, gallium-enriched inclusions containing ∼25 at % of gallium are detected as candidates for the further synthesis of gallium-nitride inclusions.

  20. Laser spectroscopy of gallium isotopes using the ISCOOL RFQ cooler

    CERN Multimedia

    Blaum, K; Kowalska, M; Ware, T; Procter, T J

    2007-01-01

    We propose to study the radioisotopes of gallium (Z=31) by collinear laser spectroscopy using the ISCOOL RFQ ion cooler. The proposed measurements on $^{62-83}$Ga will span both neutron-deficient and neutron-rich isotopes. Of key interest is the suggested development of a proton-skin in the neutron-deficient isotopes. The isotope shifts measured by laser spectroscopy will be uniquely sensitive to this feature. The measurements will also provide a wealth of new information on the gallium nuclear spins, static moments and nuclear charge radii.

  1. Early diagnosis of disc-space infection using gallium-67

    International Nuclear Information System (INIS)

    Norris, S.; Ehrlich, M.G.; Keim, D.E.; Guiterman, H.; McKusick, K.A.

    1978-01-01

    A 4-year-old boy had had progressive central lumbar pain and hamstring spasm. He had a normal lumbar-spine x-ray except for minimal L-5, S1 spondylolysis, but gave an abnormal gallium-67 scan in the region of the low lumbar spine. Eight weeks following intensive antibiotic therapy, confirmation of the diagnosis of disc-space infection was established by roentgenographic studies that demonstrated narrowing of the L 4 to 5 intervertebral disc space. A technetium-99m diphosphonate bone scan, performed concurrently with the gallium-67 study, was normal

  2. Leaching of gallium from gaiter granite, eastern desert, Egypt

    International Nuclear Information System (INIS)

    Zahran, M.A.; Mahmoud, KH.F.; Mahdy, M.A.; Abd El-Hamid, A.M.

    2006-01-01

    Preliminary leaching tests of gallium from some Egyptian granite rocks such as those of Gabal Gattar area was investigated by using 8 M HCl acid and sodium perchlorate as oxidant. To achieve the optimum leaching conditions, the factors affecting the leaching efficiency as the acid type and concentration, oxidant type and amount, leaching temperature, agitation time, solid / liquid ratio and the effect of grain size were studied. The complete chemical analysis of the collected samples was firstly carried out to determine the chemical features of the Gattarian granite. More than 97% of gallium content was leached when applying these optimum leaching conditions

  3. White beam synchrotron x-ray topography of gallium arsenide

    International Nuclear Information System (INIS)

    Winter, J.M. Jr.; Green, R.E. Jr.; Corak, W.S.

    1988-01-01

    The defect structure of gallium arsenide was investigated using white beam transmission topography. The samples were cut and polished monocrystal substrates from different suppliers. The goal of the work was to determine the viability of the method for documenting various crystallographic defect structures and establishing their effect on the performance of integrated microwave circuits fabricated on the wafers. The principles of the technique, essentially identical to classical Laue x-ray diffraction, are outlined. Two distinct defect structures were determined in the topographs. Reasons for the defect structures were postulated and the application of the method for quality control assessments of manufacturer-supplied gallium arsenide substrates was assessed

  4. Computer-assisted sequential quantitative analysis of gallium scans in pulmonary sarcoidosis

    International Nuclear Information System (INIS)

    Rohatgi, P.K.; Bates, H.R.; Noss, R.W.

    1985-01-01

    Fifty-one sequential gallium citrate scans were performed in 22 patients with biopsy-proven sarcoidosis. A computer-assisted quantitative analysis of these scans was performed to obtain a gallium score. The changes in gallium score were correlated with changes in serum angiotensin converting enzyme (SACE) activity and objective changes in clinical status. There was a good concordance between changes in gallium score, SACE activity and clinical assessment in patients with sarcoidosis, and changes in gallium index were slightly superior to SACE index in assessing activity of sarcoidosis. (author)

  5. Dehydrogenation of propane in the presence of carbon dioxide over chromium and gallium oxides catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Lapidus, A.L.; Agafonov, Yu.A.; Gaidai, N.A.; Nekrasov, N.V.; Menshova, M.V.; Kunusova, R.M. [Russian Academy of Sciences, Moscow (Russian Federation). N.D. Zelinsky Inst. of Organic Chemistry

    2011-07-01

    Effective chromium and gallium oxides supported catalysts were prepared and tested in longduration experiments for propane dehydrogenation in the presence of CO{sub 2}. The optimal concentrations of active metals were found. It was shown that the activity, selectivity and stability of chromium oxides catalysts were higher than these parameters for gallium ones. Mechanism of propane oxidative dehydrogenation was studied over both catalysts using unstationary and spectroscopic methods. The employment of these methods allowed to establish the differences in process mechanism. It was shown that surface hydroxides took participation in propene formation over Cr-catalysts and hydrides - over Ga-ones. Propane and carbon dioxide participated in the reaction from the adsorbed state over both catalysts but they were differed by the adsorption capacity of the reaction components: CO2 was tied more firmly than C{sub 3}H{sub 6} over both catalysts, CO{sub 2} and C{sub 3}H{sub 6} were tied more strongly with Cr-catalysts than with Ga-ones. It was shown that CO{sub 2} took active participation in reverse watergas shift reaction and in oxidation of catalyst surface over chromium oxides catalysts. The main role of CO{sub 2} in propane dehydrogenation over gallium catalysts consisted in a decrease of coke formation. Step-schemes of propene and cracking products formation were proposed on the basis of literature and obtained data: via the redox mechanism over Cr-catalysts and through a heterolytic dissociation reaction pathway over Ga-ones. (orig.)

  6. Uptake of gallium-67 citrate in clean surgical incisions after colorectal surgery

    International Nuclear Information System (INIS)

    Lin Wanyu; Wang Shyhjen; Tsai Shihchuan; Chao Tehsin

    2001-01-01

    Non-specific accumulation of gallium-67 citrate (gallium) in uncomplicated surgical incisions is not uncommon. It is important to know the normal pattern of gallium uptake at surgical incision sites in order to properly interpret the gallium scan when investigating possible wound infection in patients who have undergone abdominal surgery. We studied 42 patients without wound infection after colorectal surgery and performed gallium scans within 40 days after surgery. Patients were divided into three groups according to the interval between the operation and the scan. In group A (26 patients) gallium scan was performed within 7 days after surgery, in group B (8 patients) between 8 and 14 days after surgery, and in group C (8 patients) between 15 and 40 days after surgery. Our data showed that in group A, 61.5% had gallium accumulation at the surgical incision site. In group B, 50% had accumulation of gallium at the surgical incision site, while in group C only one patient (12.5%) showed gallium uptake. It is concluded that the incidence of increased gallium uptake at clean surgical incision sites is high after colorectal surgery. Nuclear medicine physicians should bear in mind the high incidence of non-specific gallium uptake at such sites during the interpretation of possible wound infection in patients after colorectal surgery. (orig.)

  7. Gallium-67 uptake by the thyroid associated with progressive systemic sclerosis

    International Nuclear Information System (INIS)

    Sjoberg, R.J.; Blue, P.W.; Kidd, G.S.

    1989-01-01

    Although thyroidal uptake of gallium-67 has been described in several thyroid disorders, gallium-67 scanning is not commonly used in the evaluation of thyroid disease. Thyroidal gallium-67 uptake has been reported to occur frequently with subacute thyroiditis, anaplastic thyroid carcinoma, and thyroid lymphoma, and occasionally with Hashimoto's thyroiditis and follicular thyroid carcinoma. A patient is described with progressive systemic sclerosis who, while being scanned for possible active pulmonary involvement, was found incidentally to have abnormal gallium-67 uptake only in the thyroid gland. Fine needle aspiration cytology of the thyroid revealed Hashimoto's thyroiditis. Although Hashimoto's thyroiditis occurs with increased frequency in patients with progressive systemic sclerosis, thyroidal uptake of gallium-67 associated with progressive systemic sclerosis has not, to our knowledge, been previously described. Since aggressive thyroid malignancies frequently are imaged by gallium-67 scintigraphy, fine needle aspiration cytology of the thyroid often is essential in the evaluation of thyroidal gallium-67 uptake

  8. Results from SAGE

    International Nuclear Information System (INIS)

    Abdurashitov, J.N.; Gavrin, V.N.; Girin, S.V.

    1996-01-01

    The Russian-American Gallium Solar Neutrino Experiment (SAGE) is described. Beginning in September 1992, SAGE II data were taken with 55 tons of Ga and with significantly reduced backgrounds. The solar neutrino flux measured by 31 extractions through October 1993 is presented. The result of 69 ± 10 +5/-7 SNU is to be compared with a Standard Solar Model prediction of 132 SNU

  9. Optical and Micro-Structural Characterization of MBE Grown Indium Gallium Nitride Polar Quantum Dots

    KAUST Repository

    El Afandy, Rami

    2011-07-07

    Gallium nitride and related materials have ushered in scientific and technological breakthrough for lighting, mass data storage and high power electronic applications. These III-nitride materials have found their niche in blue light emitting diodes and blue laser diodes. Despite the current development, there are still technological problems that still impede the performance of such devices. Three-dimensional nanostructures are proposed to improve the electrical and thermal properties of III-nitride optical devices. This thesis consolidates the characterization results and unveils the unique physical properties of polar indium gallium nitride quantum dots grown by molecular beam epitaxy technique. In this thesis, a theoretical overview of the physical, structural and optical properties of polar III-nitrides quantum dots will be presented. Particular emphasis will be given to properties that distinguish truncated-pyramidal III-nitride quantum dots from other III-V semiconductor based quantum dots. The optical properties of indium gallium nitride quantum dots are mainly dominated by large polarization fields, as well as quantum confinement effects. Hence, the experimental investigations for such quantum dots require performing bandgap calculations taking into account the internal strain fields, polarization fields and confinement effects. The experiments conducted in this investigation involved the transmission electron microscopy and x-ray diffraction as well as photoluminescence spectroscopy. The analysis of the temperature dependence and excitation power dependence of the PL spectra sheds light on the carrier dynamics within the quantum dots, and its underlying wetting layer. A further analysis shows that indium gallium nitride quantum dots through three-dimensional confinements are able to prevent the electronic carriers from getting thermalized into defects which grants III-nitrides quantum dot based light emitting diodes superior thermally induced optical

  10. Wurtzite gallium phosphide has a direct-band gap

    NARCIS (Netherlands)

    Assali, S.; Zardo, I.; Plissard, S.; Verheijen, M.A.; Haverkort, J.E.M.; Bakkers, E.P.A.M.

    2013-01-01

    Gallium Phosphide (GaP) with the normal cubic crystal structure has an indirect band gap, which severely limits the emission efficiency. We report the fabrication of GaP nanowires with pure hexagonal crystal structure and demonstrate the direct nature of the band gap. We observe strong

  11. Amorphous gallium oxide grown by low-temperature PECVD

    KAUST Repository

    Kobayashi, Eiji; Boccard, Mathieu; Jeangros, Quentin; Rodkey, Nathan; Vresilovic, Daniel; Hessler-Wyser, Aï cha; Dö beli, Max; Franta, Daniel; De Wolf, Stefaan; Morales-Masis, Monica; Ballif, Christophe

    2018-01-01

    demonstrate the growth of hydrogenated amorphous gallium oxide (a-GaO:H) thin-films by plasma-enhanced chemical vapor deposition (PECVD) at temperatures below 200 °C. In this way, conformal films are deposited at high deposition rates, achieving high broadband

  12. Targeting Gallium to Cancer Cells through the Folate Receptor

    Directory of Open Access Journals (Sweden)

    Nerissa Viola-Villegas

    2008-01-01

    Full Text Available The development of gallium(III compounds as anti-cancer agents for both treatment and diagnosis is a rapidly developing field of research. Problems remain in exploring the full potential of gallium(III as a safe and successful therapeutic agent or as an imaging agent. One of the major issues is that gallium(III compounds have little tropism for cancer cells. We have combined the targeting properties of folic acid (FA with long chain liquid polymer poly(ethylene glycol (PEG 'spacers’. This FA-PEG unit has been coupled to the gallium coordination complex of 1,4,7,10-tetraazacyclo-dodecane-N, N′, N′, N′′-tetraacetic acid (DOTA through amide linkages for delivery into target cells overexpressing the folate receptor (FR. In vitro cytotoxicity assays were conducted against a multi-drug resistant ovarian cell line (A2780/AD that overexpresses the FR and contrasted against a FR free Chinese hamster ovary (CHO cell line. Results are rationalized taking into account stability studies conducted in RPMI 1640 media and HEPES buffer at pH 7.4.

  13. Gallium uptake in benign tumor of liver: case report

    International Nuclear Information System (INIS)

    Belanger, M.A.; Beauchamp, J.M.; Neitzschman, H.R.

    1975-01-01

    A case of positive tracer localization in a benign tumor of the liver on a 67 Ga-citrate scan is reported. The authors were unable to find any previous reports of positive localization of gallium in this type of liver tumor. (U.S.)

  14. High purity liquid phase epitaxial gallium arsenide nuclear radiation detector

    International Nuclear Information System (INIS)

    Alexiev, D.; Butcher, K.S.A.

    1991-11-01

    Surface barrier radiation detector made from high purity liquid phase epitaxial gallium arsenide wafers have been operated as X- and γ-ray detectors at various operating temperatures. Low energy isotopes are resolved including 241 Am at 40 deg C. and the higher gamma energies of 235 U at -80 deg C. 15 refs., 1 tab., 6 figs

  15. Gallium Nitride MMICs for mm-Wave Power Operation

    NARCIS (Netherlands)

    Quay, R.; Maroldt, S.; Haupt, C.; Heijningen, M. van; Tessmann, A.

    2009-01-01

    In this paper a Gallium Nitride MMIC technology for high-power amplifiers between 27 GHz and 101 GHz based on 150 nm- and 100 nm-gate technologies is presented. The GaN HEMT MMICs are designed using coplanar waveguide transmission-line-technology on 3-inch semi-insulating SiC substrates. The

  16. Gallium determination with Rodamina B: a simple method

    International Nuclear Information System (INIS)

    Queiroz, R.R.U. de.

    1981-01-01

    A simple method for determining gallium with Rhodamine B, by the modification of the method proposed by Onishi and Sandell. The complex (RH) GaCl 4 is extracted with a mixture benzene-ethylacetate (3:1 V/V), from an aqueous medium 6 M in hydrochloric acid. The interference of foreign ions is studied. (C.G.C.) [pt

  17. Gallium67 scintigraphy in fibrinous pericarditis associated with bacterial endocarditis

    International Nuclear Information System (INIS)

    Martin, P.; Verhas, M.; Devriendt, J.; Goffin, Y.

    1982-01-01

    An 80-year-old man presented with pyrexia, progressive cardiac failure and inflammation. A diagnosis of pericarditisd associated with bacterial endocarditis was suggested from Gallium 67 scintigraphy and confirmed at autpsy. This case of fibrinous pericarditis without effusion could not be diagnosed by echography or routine cardiopulmonary scintigraphy. (orig.)

  18. Targeting Gallium to Cancer Cells through the Folate Receptor

    Directory of Open Access Journals (Sweden)

    Nerissa Viola-Villegas

    2008-01-01

    Full Text Available The development of gallium(III compounds as anti-cancer agents for both treatment and diagnosis is a rapidly developing field of research. Problems remain in exploring the full potential of gallium(III as a safe and successful therapeutic agent or as an imaging agent. One of the major issues is that gallium(III compounds have little tropism for cancer cells. We have combined the targeting properties of folic acid (FA with long chain liquid polymer poly(ethylene glycol (PEG ‘spacers’. This FA-PEG unit has been coupled to the gallium coordination complex of 1,4,7,10-tetraazacyclo-dodecane-N,N′,N′′,N′′′-tetraacetic acid (DOTA through amide linkages for delivery into target cells overexpressing the folate receptor (FR. In vitro cytotoxicity assays were conducted against a multi-drug resistant ovarian cell line (A2780/AD that overexpresses the FR and contrasted against a FR free Chinese hamster ovary (CHO cell line. Results are rationalized taking into account stability studies conducted in RPMI 1640 media and HEPES buffer at pH 7.4.

  19. Self- and zinc diffusion in gallium antimonide

    International Nuclear Information System (INIS)

    Nicols, Samuel Piers

    2002-01-01

    The technological age has in large part been driven by the applications of semiconductors, and most notably by silicon. Our lives have been thoroughly changed by devices using the broad range of semiconductor technology developed over the past forty years. Much of the technological development has its foundation in research carried out on the different semiconductors whose properties can be exploited to make transistors, lasers, and many other devices. While the technological focus has largely been on silicon, many other semiconductor systems have applications in industry and offer formidable academic challenges. Diffusion studies belong to the most basic studies in semiconductors, important from both an application as well as research standpoint. Diffusion processes govern the junctions formed for device applications. As the device dimensions are decreased and the dopant concentrations increased, keeping pace with Moore's Law, a deeper understanding of diffusion is necessary to establish and maintain the sharp dopant profiles engineered for optimal device performance. From an academic viewpoint, diffusion in semiconductors allows for the study of point defects. Very few techniques exist which allow for the extraction of as much information of their properties. This study focuses on diffusion in the semiconductor gallium antimonide (GaSb). As will become clear, this compound semiconductor proves to be a powerful one for investigating both self- and foreign atom diffusion. While the results have direct applications for work on GaSb devices, the results should also be taken in the broader context of III-V semiconductors. Results here can be compared and contrasted to results in systems such as GaAs and even GaN, indicating trends within this common group of semiconductors. The results also have direct importance for ternary and quaternary semiconductor systems used in devices such as high speed InP/GaAsSb/InP double heterojunction bipolar transistors (DHBT

  20. Gallium Oxide Nanostructures for High Temperature Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Chintalapalle, Ramana V. [Univ. of Texas, El Paso, TX (United States)

    2015-04-30

    Gallium oxide (Ga2O3) thin films were produced by sputter deposition by varying the substrate temperature (Ts) in a wide range (Ts=25-800 °C). The structural characteristics and electronic properties of Ga2O3 films were evaluated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), Rutherford backscattering spectrometry (RBS) and spectrophotometric measurements. The effect of growth temperature is significant on the chemistry, crystal structure and morphology of Ga2O3 films. XRD and SEM analyses indicate that the Ga2O3 films grown at lower temperatures were amorphous while those grown at Ts≥500 oC were nanocrystalline. RBS measurements indicate the well-maintained stoichiometry of Ga2O3 films at Ts=300-800 °C. The electronic structure determination indicated that the nanocrystalline Ga2O3films exhibit a band gap of ~5 eV. Tungsten (W) incorporated Ga2O3 films were produced by co-sputter deposition. W-concentration was varied by the applied sputtering-power. No secondary phase formation was observed in W-incorporated Ga2O3 films. W-induced effects were significant on the structure and electronic properties of Ga2O3 films. The band gap of Ga2O3 films without W-incorporation was ~5 eV. Oxygen sensor characteristics evaluated using optical and electrical methods indicate a faster response in W-doped Ga2O3 films compared to intrinsic Ga2O3 films. The results demonstrate the applicability of both intrinsic and W-doped Ga-oxide films for oxygen sensor application at temperatures ≥700 °C.

  1. Fabrication of magnetic nano liquid metal fluid through loading of Ni nanoparticles into gallium or its alloy

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Mingfeng; Gao, Yunxia [Key Lab of Cryogenics and Beijing Key Lab of CryoBiomedical Engineering, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Liu, Jing, E-mail: jliu@mail.ipc.ac.cn [Key Lab of Cryogenics and Beijing Key Lab of CryoBiomedical Engineering, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084 (China)

    2014-03-15

    In this study, Ni nanoparticles were loaded into the partially oxidized gallium and its alloys to fabricate desired magnetic nanofluid. It was disclosed that the Ni nanoparticles sharply increased the freezing temperature and latent heat of the obtained magnetic nano liquid metal fluid, while the melting process was less affected. For the gallium sample added with 10 vol% coated Ni particles, a hysteresis loop was observed and the magnetization intensity decreased with the increase of the temperature. The slope for the magnetization-temperature curve within 10–30 K was about 20 times of that from 40 K to 400 K. Further, the dynamic impact experiments of striking magnetic liquid metal droplets on the magnet revealed that the regurgitating of the leading edge of the liquid disk and the subsequent wave that often occurred in the gallium-indium droplets would disappear for the magnetic fluids case due to attraction force of the magnet. - Graphical abstract: High speed videos for the impact of striking GaIn{sub 24.5} based magnetic liquid metal droplets on a magnet plate. - Highlights: • A feasible way to fabricate magnetic nano liquid metal fluid was presented. • Ni nanoparticles sharply increased freezing temperature and latent heat of magnetic nanofluid. • A hysteresis loop phenomenon was observed for the magnetic nanofluid. • Temperature dependent magnetization spanning from 10 K to 400 K was measured. • Impact phenomena of striking magnetic droplets on magnet were disclosed.

  2. Measurement and modeling of magnetic hysteresis under field and stress application in iron–gallium alloys

    International Nuclear Information System (INIS)

    Evans, Phillip G.; Dapino, Marcelo J.

    2013-01-01

    Measurements are performed to characterize the hysteresis in magnetomechanical coupling of iron–gallium (Galfenol) alloys. Magnetization and strain of production and research grade Galfenol are measured under applied stress at constant field, applied field at constant stress, and alternately applied field and stress. A high degree of reversibility in the magnetomechanical coupling is demonstrated by comparing a series of applied field at constant stress measurements with a single applied stress at constant field measurement. Accommodation is not evident and magnetic hysteresis for applied field and stress is shown to be coupled. A thermodynamic model is formulated for 3-D magnetization and strain. It employs a stress, field, and direction dependent hysteron that has an instantaneous loss mechanism, similar to Coulomb-friction or Preisach-type models. Stochastic homogenization is utilized to account for the smoothing effect that material inhomogeneities have on bulk processes. - Highlights: ► We conduct coupled experiments and develop nonlinear thermodynamic models for magnetostrictive iron–gallium (Galfenol) alloys. ► The measurements show unexpected kinematic reversibility in the magnetomechanical coupling. ► This is in contrast with the magnetomechanical coupling in steel which is both thermodynamically and kinematically irreversible. ► The model accurately describes the measurements and provides a framework for understanding hysteresis in ferromagnetic materials which exhibit kinematically reversible magnetomechanical coupling.

  3. Preparation of gallium-68 radiopharmaceuticals for positron tomography. Progress report, November 1, 1978-October 31, 1979

    International Nuclear Information System (INIS)

    Welch, M.J.

    1978-06-01

    Although the germanium-gallium generator is probably the only source of positron-emitting radionuclides that would enable the wide application of positron tomography, the generator system in use suffers from several major disadvantages. The most important of these is that the generator is eluted with EDTA, and EDTA forms a very strong chelate with gallium. In order to produce radiopharmaceuticals other than gallium-68 EDTA it is necessary to break the stable EDTA complex and remove all the EDTA. A new generator system using a solvent extraction system which will produce gallium-68 8-hydroxyquinoline, a weak chelate has been developed. Using this agent, several gallium-68 radiopharmaceuticals have been synthesized and tested in vitro and in vivo. Attempts have been made using polarographic and chromatographic techniques to investigate the stability of gallium-68 complexes with a series of cryptates

  4. Angiotensin-I-converting enzyme and gallium scan in noninvasive evaluation of sarcoidosis

    International Nuclear Information System (INIS)

    Nosal, A.; Schleissner, L.A.; Mishkin, F.S.; Lieberman, J.

    1979-01-01

    Angiotensin-converting enzyme assays and gallium-scan results were obtained from 27 patients with biopsy-proven, clinically active sarcoidosis. Twenty-three of these patients had elevated converting enzyme levels, and 22 had positive gallium-scan results. Three of four patients with normal or borderline-elevated levels of angiotensin-converting enzyme also had positive gallium-scan results. Of 156 nonsarcoid patients (pulmonary and other diseases), 27 were found to have elevated serum converting enzyme levels, and 25 of these had negative gallium-scan results. These results indicate that the combination of an assay of angiotensin-converting enzyme and gallium scan increases diagnostic specificity from 83% to 99% without sacrificing sensitivity. It was concluded that the concurrent use of angiotensin-converting enzyme assay and gallium scan is of value in the diagnosis of sarcoidosis

  5. Angiotensin-I-converting enzyme and gallium scan in noninvasive evaluation of sarcoidosis

    Energy Technology Data Exchange (ETDEWEB)

    Nosal, A. (Harbor General Hospital, Torrance, CA); Schleissner, L.A.; Mishkin, F.S.; Lieberman, J.

    1979-03-01

    Angiotensin-converting enzyme assays and gallium-scan results were obtained from 27 patients with biopsy-proven, clinically active sarcoidosis. Twenty-three of these patients had elevated converting enzyme levels, and 22 had positive gallium-scan results. Three of four patients with normal or borderline-elevated levels of angiotensin-converting enzyme also had positive gallium-scan results. Of 156 nonsarcoid patients (pulmonary and other diseases), 27 were found to have elevated serum converting enzyme levels, and 25 of these had negative gallium-scan results. These results indicate that the combination of an assay of angiotensin-converting enzyme and gallium scan increases diagnostic specificity from 83% to 99% without sacrificing sensitivity. It was concluded that the concurrent use of angiotensin-converting enzyme assay and gallium scan is of value in the diagnosis of sarcoidosis.

  6. First results from SAGE II

    International Nuclear Information System (INIS)

    Abdurashitov, J.N.; Faizov, E.L.; Gavrin, V.N.

    1994-01-01

    The Russian-American Gallium solar neutrino Experiment (SAGE) began the second phase of operation (SAGE II) in September of 1992. Monthly measurements of the integral flux of solar neutrinos have been made with 55 tonnes of gallium. The K-peak results of the first five runs of SAGE II give a capture rate of 76 -18 +21 (stat) -7 +5 (sys) SNU. combined with the SAGE I result, the capture rate is 74 -12 +13 (stat) -7 +5 (sys) SNU. This represents only 56%--60% of the capture rate predicted by different Standard Solar Models

  7. Results from SAGE II

    International Nuclear Information System (INIS)

    Nico, J.S.

    1994-01-01

    The Russian-American Gallium solar neutrino Experiment (SAGE) began the second phase of operation (SAGE II) in September of 1992. Monthly measurements of the integral flux of solar neutrinos have been made with 55 tonnes of gallium. The K-peak results of the first nine runs of SAGE II give a capture rate of 66 -13 +18 (stat) -7 +5 (sys) SNU. Combined with the SAGE I result of 73 -16 +18 (stat) -7 5 (sys) SNU, the capture rate is 69 -11 +11 (stat) -7 +5 (sys) SNU. This represents only 52%--56% of the capture rate predicted by different Standard Solar Models

  8. First results from SAGE II

    International Nuclear Information System (INIS)

    Aburashitov, J.N.; Faizov, E.L.; Gavrin, V.N.; Gusev, A.O.; Kalikhov, A.V.; Knodel, T.V.; Knyshenko, I.I.; Kornoukhov, V.N.; Mirmov, I.N.; Pshukov, A.M.; Shalagin, A.M.; Shikhin, A.A.; Timofeyev, P.V.; Veretenkin, E.P.; Vermul, V.M.; Zatsepin, G.T.; Bowles, T.J.; Nico, J.S.; Teasdale, W.A.; Wark, D.L.; Wilkerson, J.F.; Cleveland, B.T.; Daily, T.; Davis, R. Jr.; Lande, K.; Lee, C.K.; Wildenhain, P.W.; Elliott, S.R.; Cherry, M.L.

    1995-01-01

    The Russian-American Gallium solar neutrino Experiment (SAGE) began the second phase of operation (SAGE II) in September of 1992. Monthly measurements of the integral flux of solar neutrinos have been made with 55 tonnes of gallium. The K-peak results of the first five runs of SAGE II give a capture rate of 76 +21 -18 (stat) +5 -7 (sys) SNU. Combined with the SAGE I result, the capture rate is 74 +13 -12 (stat) +5 -7 (sys) SNU. This represents only 56%--60% of the capture rate predicted by different Standard Solar Models. copyright 1995 American Institute of Physics

  9. Sorption of trace amounts of gallium (III) on iron (III) oxide

    Energy Technology Data Exchange (ETDEWEB)

    Music, S; Gessner, M; Wolf, R H.H. [Institut Rudjer Boskovic, Zagreb (Yugoslavia)

    1979-01-01

    The sorption of trace amounts of gallium(III) on iron(III) oxide has been studied as a function of pH. Optimum conditions have been found for the preconcentration of traces of gallium(III) by iron(III) oxide. The influence of surface active substances and of complexing agents on the sorption of trace amounts of gallium(III) on iron(III) oxide has been also studied.

  10. Critical study of the diagnostic value of lung scans using 67 gallium in respiratory diseases

    International Nuclear Information System (INIS)

    Perrin-Fayolle, M.; Brun, J.; Moret, R.; Kofman, J.; Ortonne, J.P.; Petigny, C.

    1975-01-01

    70 lungs scans using gallium 67 were carried out. Among the 41 malignant lesions, an uptake of the radio-isotope by the tumour in 51% of cases was noted. Among the 29 benign lesions, there were also 34% of cases which took up gallium 67. Their lack of reliability and selectivity make gallium 67 lung scans unsuitable for the recognition of the malignant nature of lung diseases [fr

  11. Sorption of trace amounts of gallium (III) on iron (III) oxide

    International Nuclear Information System (INIS)

    Music, S.; Gessner, M.; Wolf, R.H.H.

    1979-01-01

    The sorption of trace amounts of gallium(III) on iron(III) oxide has been studied as a function of pH. Optimum conditions have been found for the preconcentration of traces of gallium(III) by iron(III) oxide. The influence of surface active substances and of complexing agents on the sorption of trace amounts of gallium(III) on iron(III) oxide has been also studied. (orig.) [de

  12. Phenolic aminocarboxylic acids as gallium-binding radiopharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, F.C.

    1984-06-01

    The phenolic aminocarboxylic acids ethylenediamine di (o-hydroxyphenylacetic acid) (EDDHA) and N,N'-bis (2-hydroxybenzyl) ethylenediamine N,N'-diacetic acid (HBED) form gallium complexes having high stability constants which enable them to resist exchange of gallium with plasma transferrin. /sup 67/Ga complexes were synthesized with these ligands, placing substituent groups in the phenolic ring to direct excretion via the renal or hepatobiliary route. The amount of /sup 67/Ga-Br-EDDHA excreted via the hepatobiliary route was comparable with that of some of the sup(99m)Tc agents. Excretion of /sup 67/Ga-Br-HBED was similar but with delayed transit from the liver. /sup 67/Ga COOH-EDDHA was excreted exclusively via the renal route. These findings provide a basis for developing new /sup 67/Ga or /sup 68/Ga radiopharmaceuticals, the latter for use in positron emission tomography, using these phenolic aminocarboxylates.

  13. Phenolic aminocarboxylic acids as gallium-binding radiopharmaceuticals

    International Nuclear Information System (INIS)

    Hunt, F.C.

    1984-01-01

    The phenolic aminocarboxylic acids ethylenediamine di [o-hydroxyphenylacetic acid] (EDDHA) and N,N'-bis [2-hydroxybenzyl] ethylenediamine N,N'-diacetic acid (HBED) form gallium complexes having high stability constants which enable them to resist exchange of gallium with plasma transferrin. 67 Ga complexes were synthesized with these ligands, placing substituent groups in the phenolic ring to direct excretion via the renal or hepatobiliary route. The amount of 67 Ga-Br-EDDHA excreted via the hepatobiliary route was comparable with that of some of the sup(99m)Tc agents. Excretion of 67 Ga-Br-HBED was similar but with delayed transit from the liver. 67 Ga COOH-EDDHA was excreted exclusively via the renal route. These findings provide a basis for developing new 67 Ga or 68 Ga radiopharmaceuticals, the latter for use in positron emission tomography, using these phenolic aminocarboxylates. (orig.) [de

  14. Phenolic aminocarboxylic acids as gallium-binding radiopharmaceuticals.

    Science.gov (United States)

    Hunt, F C

    1984-06-01

    The phenolic aminocarboxylic acids ethylenediamine di [o-hydroxyphenylacetic acid] (EDDHA) and N,N'-bis [2-hydroxybenzyl] ethylenediamine N,N'-diacetic acid (HBED) form gallium complexes having high stability constants which enable them to resist exchange of gallium with plasma transferrin. 67Ga complexes were synthesized with these ligands, placing substituent groups in the phenolic ring to direct excretion via the renal or hepatobiliary route. The amount of 67Ga-Br-EDDHA excreted via the hepatobiliary route was comparable with that of some of the 99mTc agents. Excretion of 67Ga-Br-HBED was similar but with delayed transit from the liver. 67Ga COOH-EDDHA was excreted exclusively via the renal route. These findings provide a basis for developing new 67Ga or 68Ga radiopharmaceuticals, the latter for use in positron emission tomography, using these phenolic aminocarboxylates.

  15. Usefulness of gallium imaging in the evaluation of lung cancer

    International Nuclear Information System (INIS)

    Alazraki, N.

    1980-01-01

    The current enthusiasm for gallium (Ga) citrate as a tumor imaging agent reflects the need of clinical medicine for a good tumor imaging agent. Ga-67 was most consistently and reliably taken up in lung tumors, with sensitivities of Ga imaging positivity in lung cancer ranging from 85 to 95%. Subsequent studies on Ga-67 led to the recognition of its preferential concentration in inflammatory lesions and abscess. These reports resulted in the clinical application of Ga-67 imaging as a diagnostic tool in the evaluation of patients with suspected abscesses. Mechanisms of Ga localization in tumor and inflammatory lesions are not currently well understood. Data regarding the thresholds of various factors which determine visibility of a lung tumor by Ga-67 imaging have been described in some detail. The factors include lesion size, depth in tissue, gallium concentration in tumor relative to background, type of film and instrumentation used, and count rates obtained

  16. Electrophoretic Deposition of Gallium with High Deposition Rate

    Directory of Open Access Journals (Sweden)

    Hanfei Zhang

    2014-12-01

    Full Text Available In this work, electrophoretic deposition (EPD is reported to form gallium thin film with high deposition rate and low cost while avoiding the highly toxic chemicals typically used in electroplating. A maximum deposition rate of ~0.6 μm/min, almost one order of magnitude higher than the typical value reported for electroplating, is obtained when employing a set of proper deposition parameters. The thickness of the film is shown to increase with deposition time when sequential deposition is employed. The concentration of Mg(NO32, the charging salt, is also found to be a critical factor to control the deposition rate. Various gallium micropatterns are obtained by masking the substrate during the process, demonstrating process compatibility with microfabrication. The reported novel approach can potentially be employed in a broad range of applications with Ga as a raw material, including microelectronics, photovoltaic cells, and flexible liquid metal microelectrodes.

  17. Ultra-low threshold gallium nitride photonic crystal nanobeam laser

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Nan, E-mail: nanniu@fas.harvard.edu; Woolf, Alexander; Wang, Danqing; Hu, Evelyn L. [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Zhu, Tongtong; Oliver, Rachel A. [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Quan, Qimin [Rowland Institute at Harvard University, Cambridge, Massachusetts 02142 (United States)

    2015-06-08

    We report exceptionally low thresholds (9.1 μJ/cm{sup 2}) for room temperature lasing at ∼450 nm in optically pumped Gallium Nitride (GaN) nanobeam cavity structures. The nanobeam cavity geometry provides high theoretical Q (>100 000) with small modal volume, leading to a high spontaneous emission factor, β = 0.94. The active layer materials are Indium Gallium Nitride (InGaN) fragmented quantum wells (fQWs), a critical factor in achieving the low thresholds, which are an order-of-magnitude lower than obtainable with continuous QW active layers. We suggest that the extra confinement of photo-generated carriers for fQWs (compared to QWs) is responsible for the excellent performance.

  18. Ultra-low threshold gallium nitride photonic crystal nanobeam laser

    International Nuclear Information System (INIS)

    Niu, Nan; Woolf, Alexander; Wang, Danqing; Hu, Evelyn L.; Zhu, Tongtong; Oliver, Rachel A.; Quan, Qimin

    2015-01-01

    We report exceptionally low thresholds (9.1 μJ/cm 2 ) for room temperature lasing at ∼450 nm in optically pumped Gallium Nitride (GaN) nanobeam cavity structures. The nanobeam cavity geometry provides high theoretical Q (>100 000) with small modal volume, leading to a high spontaneous emission factor, β = 0.94. The active layer materials are Indium Gallium Nitride (InGaN) fragmented quantum wells (fQWs), a critical factor in achieving the low thresholds, which are an order-of-magnitude lower than obtainable with continuous QW active layers. We suggest that the extra confinement of photo-generated carriers for fQWs (compared to QWs) is responsible for the excellent performance

  19. Neutron detection using boron gallium nitride semiconductor material

    Directory of Open Access Journals (Sweden)

    Katsuhiro Atsumi

    2014-03-01

    Full Text Available In this study, we developed a new neutron-detection device using a boron gallium nitride (BGaN semiconductor in which the B atom acts as a neutron converter. BGaN and gallium nitride (GaN samples were grown by metal organic vapor phase epitaxy, and their radiation detection properties were evaluated. GaN exhibited good sensitivity to α-rays but poor sensitivity to γ-rays. Moreover, we confirmed that electrons were generated in the depletion layer under neutron irradiation. This resulted in a neutron-detection signal after α-rays were generated by the capture of neutrons by the B atoms. These results prove that BGaN is useful as a neutron-detecting semiconductor material.

  20. Concentration of gallium in the Permo-Carboniferous coals of China

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Cunliang; Qin, Shenjun; Yang, Yinchao; Li, Yanheng; Lin, Mingyue [Hebei University of Engineering, Handan (China)

    2009-10-15

    Gallium is widely used in electronic industry and its current price is about 500 US dollars per kilogram. It has been found that its contents are very high in Permo-Carboniferous coal of China. In order to look for valuable associated gallium deposits in coal, gallium contents of 177 coal samples were determined by using inductively coupled plasma-mass spectrometry (ICP-MS) and the data of 873 coal samples from Chinese Permo-Carboniferous coalfields were collected. The results show that the average gallium concentration of Chinese Permo-Carboniferous coals is 15.49{mu}g{center_dot}g{sup -1}. There are two concentration types of gallium in Chinese Permo-Carboniferous coals: one type is that gallium has enriched to an ore deposit, and another type is that gallium is locally enriched in coal seams, but has not formed a valuable associated gallium ore deposit. The gallium concentration in Chinese Permo-Carboniferous coal may have several different sources: concentration in sedimentation stage, magmatic hydrothermal inputs and low-temperature hydrothermal fluids.

  1. Cutaneous gallium uptake in patients with AIDS with mycobacterium avium-intracellulare septicemia

    International Nuclear Information System (INIS)

    Allwright, S.J.; Chapman, P.R.; Antico, V.F.; Gruenewald, S.M.

    1988-01-01

    Gallium imaging is increasingly being used for the early detection of complications in patients with AIDS. A 26-year-old homosexual man who was HIV antibody positive underwent gallium imaging for investigation of possible Pneumocystis carinii pneumonia. Widespread cutaneous focal uptake was seen, which was subsequently shown to be due to mycobacterium avium-intracellulare (MAI) septicemia. This case demonstrates the importance of whole body imaging rather than imaging target areas only, the utility of gallium imaging in aiding the early detection of clinically unsuspected disease, and shows a new pattern of gallium uptake in disseminated MAI infection

  2. A case of muscular sarcoidosis diagnosed by gallium-67 scintigraphy and magnetic resonance imaging

    International Nuclear Information System (INIS)

    Sohn, Hyung Sun; Kim, Euy Neyng

    1999-01-01

    Gallium-67 scintigraphy is helpful in the assessment of active extrapulmonary sarcoidosis. Muscular involvement of sarcoidosis is often asymptomatic or nonspecific, and laboratory examinations do not provide convincing evidence of muscular involvement. We report a case of muscular sarcoidosis, which was detected by gallium-67 scintigraphy. In a patient who was suffering from fever and arthalgia of knee joint, gallium-67 scintigraphy showed mediastinal and hilar involvement of sarcoidosis with unexpected extensive muscular uptake. Magnetic resonance imaging revealed the detailed depiction of intramuscular infiltration of sarcoid granuloma. Gallium-67 scintigraphy is useful in detecting inflammatory muscular involvement of sarcoidosis as well as other multiorgan involvement

  3. Liquid gallium cooling of silicon crystals in high intensity photon beams

    International Nuclear Information System (INIS)

    Smither, R.K.; Forster, G.A.; Bilderback, D.H.; Bedzyk, M.; Finkelstein, K.; Henderson, C.; White, J.; Berman, L.E.; Stefan, P.; Oversluizen, T.

    1989-01-01

    The high-brilliance, insertion-device-based photon beams of the next generation of synchrotron sources (Argonne's APS and Grenoble's ESRF) will deliver large thermal loads (1--10 kW) to the first optical elements. Considering the problems that present synchrotron users are experiencing with beams from recently installed insertion devices, new and improved methods of cooling these first optical elements, particularly when they are diffraction crystals, are clearly needed. A series of finite element calculations were performed to test the efficiency of new cooling geometries and various cooling fluids. The best results were obtained with liquid Ga metal flowing in channels just below the surface of the crystal. Ga was selected because of its good thermal conductivity and thermal capacity, low melting point, high boiling point, low kinetic viscosity, and very low vapor pressure. Its very low vapor pressure, even at elevated temperatures, makes it especially attractive in UHV conditions. A series of experiments were conducted at CHESS in February of 1988 that compared liquid gallium-cooled silicon diffraction crystals with water-cooled crystals. A six-pole wiggler beam was used to perform these tests on three different Si crystals, two with new cooling geometries and the one presently in use. A special high-pressure electromagnetic induction pump, recently developed at Argonne, was used to circulate the liquid gallium through the silicon crystals. In all experiments, the specially cooled crystal was used as the first crystal in a two crystal monochromator. An infrared camera was used to monitor the thermal profiles and correlated them with rocking curve measurements. A second set of cooling experiments were conducted in June of 1988 that used the intense, highly collimated beam from the newly installed ANL/CHESS undulator

  4. Latest progress in gallium-oxide electronic devices

    Science.gov (United States)

    Higashiwaki, Masataka; Wong, Man Hoi; Konishi, Keita; Nakata, Yoshiaki; Lin, Chia-Hung; Kamimura, Takafumi; Ravikiran, Lingaparthi; Sasaki, Kohei; Goto, Ken; Takeyama, Akinori; Makino, Takahiro; Ohshima, Takeshi; Kuramata, Akito; Yamakoshi, Shigenobu; Murakami, Hisashi; Kumagai, Yoshinao

    2018-02-01

    Gallium oxide (Ga2O3) has emerged as a new competitor to SiC and GaN in the race toward next-generation power switching and harsh environment electronics by virtue of the excellent material properties and the relative ease of mass wafer production. In this proceedings paper, an overview of our recent development progress of Ga2O3 metal-oxide-semiconductor field-effect transistors and Schottky barrier diodes will be reported.

  5. Assessment of arsenic exposures and controls in gallium arsenide production.

    Science.gov (United States)

    Sheehy, J W; Jones, J H

    1993-02-01

    The electronics industry is expanding the use of gallium arsenide in the production of optoelectronic devices and integrated circuits. Workers in the electronics industry using gallium arsenide are exposed to hazardous substances such as arsenic, arsine, and various acids. Arsenic requires stringent controls to minimize exposures (the current OSHA PEL for arsenic is 10 micrograms/m3 and the NIOSH REL is 2 micrograms/m3 ceiling). Inorganic arsenic is strongly implicated in respiratory tract and skin cancer. For these reasons, NIOSH researchers conducted a study of control systems for facilities using gallium arsenide. Seven walk-through surveys were performed to identify locations for detailed study which appeared to have effective controls; three facilities were chosen for in-depth evaluation. The controls were evaluated by industrial hygiene sampling. Including personal breathing zone and area air sampling for arsenic and arsine; wipe samples for arsenic also were collected. Work practices and the use of personal protective equipment were documented. This paper reports on the controls and the arsenic exposure results from the evaluation of the following gallium arsenide processes: Liquid Encapsulated Czochralski (LEC) and Horizontal Bridgeman (HB) crystal growing, LEC cleaning operations, ingot grinding/wafer sawing, and epitaxy. Results at one plant showed that in all processes except epitaxy, average arsenic exposures were at or above the OSHA action level of 5 micrograms/m3. While cleaning the LEC crystal pullers, the average potential arsenic exposure of the cleaning operators was 100 times the OSHA PEL. At the other two plants, personal exposures for arsenic were well controlled in LEC, LEC cleaning, grinding/sawing, and epitaxy operations.

  6. Diagnosis of mycotic abdominal aortic aneurysm using 67-gallium citrate

    International Nuclear Information System (INIS)

    Blumoff, R.L.; McCartney, W.; Jaques, P.; Johnson, G. Jr.

    1982-01-01

    Mycotic aneurysms of the abdominal aorta are uncommon, but potentially lethal problems. Clinical subtleties may suggest their presence, but in the past, definitive diagnosis has been dependent on surgical exploration or autopsy findings. A case is presented in which 67-gallium citrate abdominal scanning localized the site of sepsis in an abdominal aortic aneurysm and allowed for prompt and successful surgical therapy. This noninvasive technique is recommended as a adjunct in the diagnosis of mycotic abdominal aortic aneurysms

  7. Incidental diagnosis of pregnancy on bone and gallium scintigraphy

    International Nuclear Information System (INIS)

    Palestro, C.J.; Malat, J.; Collica, C.J.; Richman, A.H.

    1986-01-01

    Bone and gallium scintigraphy were performed as part of the diagnostic workup of a 21-yr-old woman who presented at our institution with a history of progressively worsening low back pain over a 1-wk period of time. The angiographic phase of the bone scan demonstrated a well-defined radionuclide blush within the pelvis just cephalad to the urinary bladder with persistent hyperemia noted in the blood-pool image. We attribute these findings to a uterine blush secondary to the pronounced uterine muscular hyperplasia, hyperemia, and edema that accompany pregnancy. Gallium scintigraphy demonstrated intense bilateral breast accumulation of the imaging agent in a typical doughnut pattern which is commonly found in the prelactating and lactating breast. Also demonstrated was apparent gallium accumulation in the placenta. This case is presented to emphasize the radionuclide findings that occur during pregnancy, particularly the incidental finding of radionuclide blush during the angiographic phase of a radionuclide scintigraphy which should alert the nuclear physician to the possibility of pregnancy in a woman of childbearing age

  8. Challenges for critical raw material recovery from WEEE - The case study of gallium.

    Science.gov (United States)

    Ueberschaar, Maximilian; Otto, Sarah Julie; Rotter, Vera Susanne

    2017-02-01

    Gallium and gallium compounds are more frequently used in future oriented technologies such as photovoltaics, light diodes and semiconductor technology. In the long term the supply risk is estimated to be critical. Germany is one of the major primary gallium producer, recycler of gallium from new scrap and GaAs wafer producer. Therefore, new concepts for a resource saving handling of gallium and appropriate recycling strategies have to be designed. This study focus on options for a possible recycling of gallium from waste electric and electronic equipment. To identify first starting points, a substance flow analysis was carried out for gallium applied in integrated circuits applied on printed circuit boards and for LEDs used for background lighting in Germany in 2012. Moreover, integrated circuits (radio amplifier chips) were investigated in detail to deduce first approaches for a recycling of such components. An analysis of recycling barriers was carried out in order to investigate general opportunities and risks for the recycling of gallium from chips and LEDs. Results show, that significant gallium losses arose in primary production and in waste management. 93±11%, equivalent to 43,000±4700kg of the total gallium potential was lost over the whole primary production process until applied in electronic goods. The largest share of 14,000±2300kggallium was lost in the production process of primary raw materials. The subsequent refining process was related to additional 6900±3700kg and the chip and wafer production to 21,700±3200kg lost gallium. Results for the waste management revealed only low collection rates for related end-of-life devices. Not collected devices held 300 ± 200 kg gallium. Due to the fact, that current waste management processes do not recover gallium, further 80 ± 10 kg gallium were lost. A thermal pre-treatment of the chips, followed by a manual separation allowed an isolation of gallium rich fractions, with gallium mass fractions up to

  9. Study of breakdown voltage of indium-gallium-zinc-oxide-based Schottky diode

    Energy Technology Data Exchange (ETDEWEB)

    Xin, Qian; Yan, Linlong; Luo, Yi [School of Physics, Shandong University, Jinan 250100 (China); Song, Aimin, E-mail: A.Song@manchester.ac.uk [School of Physics, Shandong University, Jinan 250100 (China); School of Electrical and Electronic Engineering, University of Manchester, Manchester M13 9PL (United Kingdom)

    2015-03-16

    In contrast to the intensive studies on thin-film transistors based on indium gallium zinc oxide (IGZO), the research on IGZO-based diodes is still very limited, particularly on their behavior and stability under high bias voltages. Our experiments reveal a sensitive dependence of the breakdown voltage of IGZO Schottky diodes on the anode metal and the IGZO film thickness. Devices with an Au anode are found to breakdown easily at a reverse bias as low as −2.5 V, while the devices with a Pd anode and a 200-nm, fully depleted IGZO layer have survived up to −15 V. All diodes are fabricated by radio-frequency magnetron sputtering at room temperature without any thermal treatment, yet showing an ideality factor as low as 1.14, showing the possibility of achieving high-performance Schottky diodes on flexible plastic substrate.

  10. Study of breakdown voltage of indium-gallium-zinc-oxide-based Schottky diode

    International Nuclear Information System (INIS)

    Xin, Qian; Yan, Linlong; Luo, Yi; Song, Aimin

    2015-01-01

    In contrast to the intensive studies on thin-film transistors based on indium gallium zinc oxide (IGZO), the research on IGZO-based diodes is still very limited, particularly on their behavior and stability under high bias voltages. Our experiments reveal a sensitive dependence of the breakdown voltage of IGZO Schottky diodes on the anode metal and the IGZO film thickness. Devices with an Au anode are found to breakdown easily at a reverse bias as low as −2.5 V, while the devices with a Pd anode and a 200-nm, fully depleted IGZO layer have survived up to −15 V. All diodes are fabricated by radio-frequency magnetron sputtering at room temperature without any thermal treatment, yet showing an ideality factor as low as 1.14, showing the possibility of achieving high-performance Schottky diodes on flexible plastic substrate

  11. Method of determination of radiochemical purity of gallium-67 citrate injection

    International Nuclear Information System (INIS)

    Wang Quanji

    1985-01-01

    A simple method is used to compare the effect of five developing agents on the radiochemical purity of neutral products of 67 GaCit and on Rsub(f) values. Two preferable developing agents are recommended as suitable for the identification of 67 GaCit injection in its production. The effect of six pH values of different developing agents on radiochemical purity, Rsub(f) and chromatogram are compared for the neutral products. The results of the experiments show that the ascending paper chromatography with 1:2:4 pyridine/ethanol/water and 85:15 methanol/water is preferable for the determination of the radiochemical purity of 67 GaCit. The other developing agents also can be used if there are not any impurities except gallium radioisotopes

  12. Variation of crystallinity and stoichiometry in films of gallium oxide, gallium nitride and barium zirconate prepared by means of PLD

    International Nuclear Information System (INIS)

    Brendt, Jochen

    2011-01-01

    Pulsed Laser Deposition (PLD) is an ablation technique for thin film preparation of many materials. The film properties can be well controlled by the process parameters. Therefore, in many cases a given material can be deposited with different properties by changing one or more process parameters. In this thesis thin films of gallium oxide, gallium nitride and barium zirconate were deposited with a large variation in structure and stoichiometry by means of Pulsed Laser Deposition. The characterization of the film crystallinity, phase purity and short range structural order was completed by means of X-ray diffraction and X-ray absorption spectroscopy. The stoichiometry was investigated using electron probe microanalysis. For analyzing the correlation between the structure and stoichiometry with the optical and electrical properties, optical absorption and electrical conductivity measurements were carried out. The investigation of all three material systems showed that very unique properties can be realized when combining an amorphous structure and a non-stoichiometric composition. For example, in amorphous and oxygen deficient gallium oxide an insulator-metal-transition can be induced by partial crystallization of the as prepared phase accomplished by annealing at about 400 C in argon atmosphere (as shown in literature). Furthermore, amorphous and highly non-stoichiometric barium zirconate has the ability to split water molecules to hydrogen and oxygen at room temperature. A detailed analysis of both phenomena has been performed by means of photoemission and transmission electron microscopy in the case of gallium oxide and via X-ray absorption spectroscopy and gas chromatography in the case of barium zirconate.

  13. POLLUTION PREVENTION IN THE SEMICONDUCTOR INDUSTRY THROUGH RECOVERY AND RECYCLING OF GALLIUM AND ARSENIC FROM GAAS POLISHING WASTES

    Science.gov (United States)

    A process was developed for the recovery of both arsenic and gallium from gallium arsenide polishing wastes. The economics associated with the current disposal techniques utilizing ferric hydroxide precipitation dictate that sequential recovery of toxic arsenic and valuble galliu...

  14. Elastic properties of crystalline and liquid gallium at high pressures

    Science.gov (United States)

    Lyapin, A. G.; Gromnitskaya, E. L.; Yagafarov, O. F.; Stal'Gorova, O. V.; Brazhkin, V. V.

    2008-11-01

    The elastic properties of gallium, such as the bulk modulus B, the shear modulus G, and the Poisson’s ratio σ, are investigated and the relative change in the volume is determined in the stability regions of the Ga I, Ga II, and liquid phases at pressures of up to 1.7 GPa. The observed lines of the Ga I-Ga II phase transition and the melting curves of the Ga I and Ga II phases are in good agreement with the known phase diagram of gallium; in this case, the coordinates of the Ga I-Ga II-melt triple point are determined to be 1.24 ± 0.40 GPa and 277 ± 2 K. It is shown that the Ga I-Ga II phase transition is accompanied by a considerable decrease in the moduli B (by 30%) and G (by 55%) and an increase in the density by 5.7%. The Poisson’s ratio exhibits a jump from typically covalent values of approximately 0.22-0.25 to values of approximately 0.32-0.33, which are characteristic of metals. The observed behavior of the elastic characteristics is described in the framework of the model of the phase transition from a “quasi-molecular” (partially covalent) metal state to a “normal” metal state. An increase in the Poisson’s ratio in the Ga I phase from 0.22 to 0.25 with an increase in the pressure can be interpreted as a decrease in the degree of covalence, i.e., the degree of spatial anisotropy of the electron density along the bonds, whereas the large value of the pressure derivative of the bulk modulus (equal to approximately 8) observed up to the transition to the Ga II phase or the melt is associated not only with the quasicovalent nature of the Ga I phase but also with the structural features. In view of the presence of seven neighbors for each gallium atom in the Ga I phase, the gallium lattice can be treated as a structure intermediate between typical open-packed and close-packed structures. Premelting effects, such as a flattening of the isothermal dependence of the shear modulus G( p) with increasing pressure and an increase in the slope of the

  15. Elastic properties of crystalline and liquid gallium at high pressures

    International Nuclear Information System (INIS)

    Lyapin, A. G.; Gromnitskaya, E. L.; Yagafarov, O. F.; Stal'gorova, O. V.; Brazhkin, V. V.

    2008-01-01

    The elastic properties of gallium, such as the bulk modulus B, the shear modulus G, and the Poisson's ratio σ, are investigated and the relative change in the volume is determined in the stability regions of the Ga I, Ga II, and liquid phases at pressures of up to 1.7 GPa. The observed lines of the Ga I-Ga II phase transition and the melting curves of the Ga I and Ga II phases are in good agreement with the known phase diagram of gallium; in this case, the coordinates of the Ga I-Ga II-melt triple point are determined to be 1.24 ± 0.40 GPa and 277 ± 2 K. It is shown that the Ga I-Ga II phase transition is accompanied by a considerable decrease in the moduli B (by 30%) and G (by 55%) and an increase in the density by 5.7%. The Poisson's ratio exhibits a jump from typically covalent values of approximately 0.22-0.25 to values of approximately 0.32-0.33, which are characteristic of metals. The observed behavior of the elastic characteristics is described in the framework of the model of the phase transition from a 'quasi-molecular' (partially covalent) metal state to a 'normal' metal state. An increase in the Poisson's ratio in the Ga I phase from 0.22 to 0.25 with an increase in the pressure can be interpreted as a decrease in the degree of covalence, i.e., the degree of spatial anisotropy of the electron density along the bonds, whereas the large value of the pressure derivative of the bulk modulus (equal to approximately 8) observed up to the transition to the Ga II phase or the melt is associated not only with the quasicovalent nature of the Ga I phase but also with the structural features. In view of the presence of seven neighbors for each gallium atom in the Ga I phase, the gallium lattice can be treated as a structure intermediate between typical open-packed and close-packed structures. Premelting effects, such as a flattening of the isothermal dependence of the shear modulus G(p) with increasing pressure and an increase in the slope of the isobaric

  16. High field magnetic anisotropy in praseodymium gallium garnet at low temperatures

    International Nuclear Information System (INIS)

    Wang Wei; Yue Yuan; Liu Gongqiang

    2011-01-01

    Research highlights: → A detailed analysis of crystal field effect is presented, and a set of new crystal field parameters is given to study the magnetic behaviors of the paramagnetic praseodymium gallium garnet (PrGaG). → The contribution of the exchange interaction between the praseodymium ions to the magnetic properties of PrGaG is further explored. Meanwhile, some characteristics of exchange interaction are revealed. → With the consideration of crystal field and exchange interaction, the available experiments are successfully fitted by our theoretical model. → Our theory suggests that PrGaG is ferromagnetic ordering at low temperatures, and the exchange interaction is anisotropic. - Abstract: In this paper, with the consideration of crystal field and exchange interaction between the rare-earth Pr 3+ ions, the magnetic anisotropy in praseodymium gallium garnet (PrGaG) in high magnetic fields and at low temperatures is theoretically analyzed. A set of relatively suitable CF parameters is obtained by studying the influence of the variations of nine CF parameters on the magnetization. However, only taking crystal field effect into account, theoretical calculations indicate that the experiments cannot be excellently interpreted. Then, the exchange interaction between Pr 3+ ion, which can be described as an effective exchange field H v = vM = vχH e = ηH e , is further considered. On the other hand, by evaluating the variation of the parameter η with the magnetic fields, our theory implies that PrGaG exhibits ferrimagnetic ordering at low temperatures, and the exchange interaction in PrGaG displays obvious anisotropy. Also, the theoretical data show better agreements with the experimental results.

  17. Radiochemical solar neutrino experiments

    International Nuclear Information System (INIS)

    Rich, R.; Spiro, M.

    1993-01-01

    This review covers the three presently running radiochemical solar neutrino experiments, namely the Chlorine, SAGE, and GALLEX experiments. The focus of the review is on a discussion of statistical consistency checks of the available data. The chlorine radiochemical experiment is conceptually simple and shows no strong indication of any statistical anomalies. It still forms the basis of the solar neutrino problem. Each of the two gallium experiments show internal statistical consistency. SAGE's recent preliminary results are consistent with the published GALLEX results. If this convergence is confirmed by a more definitive analysis, this would suggest that the combined result of the two gallium experiments, SAGE and GALLEX, be used for comparisons with theoretical expectations. 5 refs., 15 figs

  18. X-Ray Scattering Studies of the Liquid-Vapor Interface of Gallium.

    Science.gov (United States)

    Kawamoto, Eric Hitoshi

    A UHV system was developed for performing X-ray scattering studies and in situ analyses of liquid metal surfaces. A nearly ideal choice for this study, gallium has a melting point just above room temperature; is amenable to handling in both air and vacuum; its surface oxides can be removed while its cleanliness is maintained and monitored. Using argon glow-discharge sputtering techniques to remove intervening surface oxides, thin wetting layers of gallium were prepared atop nonreactive substrates, to be used as samples suited for liquid surface scattering experiments. Preliminary measurements of X-ray reflectivity from the liquid-vapor interface of gallium were performed with the X-ray UHV chamber configured for use in conjunction with liquid surface spectrometers at two synchrotron beamlines. A novel technique for carrying out and interpreting scattering measurements from curved liquid surfaces was demonstrated. The energy tunability and intense focused white beam flux from a wiggler source was shown to place within reach the large values of wavevector transfer at which specular reflectivity data yield small length scale information about surface structure. Various theoretical treatments and simulations predict quasi-lamellar ordering of atoms near the free surface of metallic liquids due to energetics particular to metals (electron delocalization, the dependence of system energy on ion and electron densities, surface tension and electrostatic energy). However, the experimental data reported to date is insufficient to distinguish between a monotonic, sigmoidal electron density profile found at the free surfaces of dielectric liquids, and the damped oscillatory layer-like profiles anticipated for metallic liquids. Out to a wavevector transfer of Q = 0.55 A ^{-1}, the reflectivity data measured from a curved Ga surface is not inconsistent with what is expected for a liquid-vapor electron density profile of Gaussian width sigma = 1.3 +/- 0.2 A. Subsequent

  19. Russian-American relations and the future of arms control

    International Nuclear Information System (INIS)

    Trenin, D.

    2001-01-01

    This article describes the progressive drift of the US-Russia nuclear military policies, the implications for Russia of the US missile defense program (MDP) and its progress in the framework of President Bush administration, Russia's strategy and tactics to incite the US to continue strategic weapons reduction, the Russian theater missile defense (TMD) proposal and its philosophy, and the future necessary collaboration between the US, the EU and Russia to deal with the challenge of proliferation. (J.S.)

  20. Russian-American relations and the future of arms control

    Energy Technology Data Exchange (ETDEWEB)

    Trenin, D

    2001-07-01

    This article describes the progressive drift of the US-Russia nuclear military policies, the implications for Russia of the US missile defense program (MDP) and its progress in the framework of President Bush administration, Russia's strategy and tactics to incite the US to continue strategic weapons reduction, the Russian theater missile defense (TMD) proposal and its philosophy, and the future necessary collaboration between the US, the EU and Russia to deal with the challenge of proliferation. (J.S.)

  1. Proceedings of the joint Russian-American hydrogeology seminar

    International Nuclear Information System (INIS)

    Tsang, C.F.; Mironenko, V.

    1997-01-01

    Hydrogeology research has been very active in both Russia and the US because of the concerns for migration of radioactive and chemical contaminants in soils and geologic formations, as well as for water problems related to mining and other industrial operations. Russian hydrogeologists have developed various analysis and field testing techniques, sometimes in parallel with US counterparts. These Proceedings come out of a Seminar held to bring together a small group (about 15) of active Russian researchers in geologic flow and transport associated with the disposal of radioactive and chemical wastes either on the soils or through deep injection wells, with a corresponding group (about 25) of American hydrogeologists. The meeting was intentionally kept small to enable informal, detailed and in-depth discussions on hydrogeological issues of common interest. Out of this interaction, the authors hope that, firstly, they will have learned from each other and secondly, that research collaborations will be established where there is the opportunity. This proceedings presents the summaries and viewgraphs from the presentations. What cannot be conveyed here is the warm and cooperative atmosphere of these interactions, both inside and outside the formal sessions, which may well lead to future collaborations

  2. Russian-American relations and the future of arms control

    Energy Technology Data Exchange (ETDEWEB)

    Trenin, D

    2001-07-01

    This article describes the progressive drift of the US-Russia nuclear military policies, the implications for Russia of the US missile defense program (MDP) and its progress in the framework of President Bush administration, Russia's strategy and tactics to incite the US to continue strategic weapons reduction, the Russian theater missile defense (TMD) proposal and its philosophy, and the future necessary collaboration between the US, the EU and Russia to deal with the challenge of proliferation. (J.S.)

  3. Phenolic aminocarboxylic acids - new chelating agents for modifying gallium-67 biodistribution

    International Nuclear Information System (INIS)

    Hunt, F.C.; Maddalena, D.J.

    1982-01-01

    The chelating agents EDDHA and HBED were synthesised with carboxyl or sulphonyl groups in the phenolic ring to favour urinary excretion on complexing with gallium. Carboxyl EDDMA was administered to tumor-bearing rats, and its concentration in the tumours and other tissues determined by scintigraphic imaging. The chelating agents increase tumour to blood ratios by chelating gallium in vivo. (U.K.)

  4. Phenolic aminocarboxylic acids - new chelating agents for modifying gallium-67 biodistribution

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, F.C.; Maddalena, D.J. (Australian Atomic Energy Commission Research Establishment, Lucas Heights)

    The chelating agents EDDHA and HBED were synthesised with carboxyl or sulphonyl groups in the phenolic ring to favour urinary excretion on complexing with gallium. Carboxyl EDDMA was administered to tumor-bearing rats, and its concentration in the tumours and other tissues determined by scintigraphic imaging. The chelating agents increase tumour to blood ratios by chelating gallium in vivo.

  5. Gallium nitrate: effects on cartilage during limb regeneration in the axolotl, Ambystoma mexicanum.

    Science.gov (United States)

    Tassava, Roy A; Mendenhall, Luciara; Apseloff, Glen; Gerber, Nicholas

    2002-09-01

    Gallium nitrate, a drug shown to have efficacy in Paget's disease of bone, hypercalcemia of malignancy, and a variety of experimental autoimmune diseases, also inhibits the growth of some types of cancer. We examined dose and timing of administration of gallium nitrate on limb regeneration in the Mexican axolotl, Ambystoma mexicanum. Administered by intraperitoneal injection, gallium nitrate inhibited limb regeneration in a dose-dependent manner. Gallium nitrate initially suppressed epithelial wound healing and subsequently distorted both anterior-posterior and proximo-distal chondrogenic patterns. Gallium nitrate given at three days after amputation severely inhibited regeneration at high doses (6.25 mg/axolotl) and altered the normal patterning of the regenerates at low doses (3.75 mg/axolotl). Administration of 6.25 mg of gallium nitrate at four or 14 days prior to amputation also inhibited regeneration. In amputated limbs of gallium-treated axolotls, the chondrocytes were lost from inside the radius/ulna. Limbs that regenerated after gallium treatment was terminated showed blastema formation preferentially over the ulna. New cartilage of the regenerate often attached to the sides of the existing radius/ulna proximally into the stump and less so to the distal cut ends. J. Exp. Zool. 293:384-394, 2002. Copyright 2002 Wiley-Liss, Inc.

  6. Patchy uptake of gallium in the lungs of AIDS patients with atypical mycobacterial infection

    International Nuclear Information System (INIS)

    Skarzynski, J.J.; Sherman, W.; Lee, H.K.; Berger, H.

    1987-01-01

    The gallium scans of seven AIDS patients who cultured positive for atypical mycobacterium were reviewed. Six cultured positive for Mycobacterium avium intracellulare, while one for Mycobacterium xenopi. A patchy uptake pattern of gallium in the lungs of these patients was identified

  7. Gallium-67 Citrate uptake in cryptoccal thyroiditis in a Homosexual male

    International Nuclear Information System (INIS)

    Machac, J.; Nejatheim, M.; Goldsmith, S.J.

    1985-01-01

    A case of disseminated cryptococcosis and autopsy proven cryptococcal thyroiditis is described in a homosexual male. Thyroid uptake of Gallium-67 citrate was seen one week prior to positive blood cultures. This finding was the sole indication of thyroid involvement. Focal Gallium uptake may be considered as an indication for biopsy and culture in the initial work up of this group of immunocompromised hosts

  8. Selective growth of gallium nitride nanowires by femtosecond laser patterning

    Energy Technology Data Exchange (ETDEWEB)

    Ng, D.K.T. [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore); Data Storage Institute, Agency for Science, Technology and Research, DSI Building, 5 Engineering Drive 1, Singapore 117608 (Singapore); Hong, M.H. [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore); Data Storage Institute, Agency for Science, Technology and Research, DSI Building, 5 Engineering Drive 1, Singapore 117608 (Singapore)], E-mail: HONG_Minghui@dsi.a-star.edu.sg; Tan, L.S. [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore); Zhou, Y. [Data Storage Institute, Agency for Science, Technology and Research, DSI Building, 5 Engineering Drive 1, Singapore 117608 (Singapore); Department of Mechanical Engineering, National University of Singapore, 2 Engineering Drive 3, Singapore 117576 (Singapore); Chen, G.X. [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore)

    2008-01-31

    We report on gallium nitride (GaN) nanowires grown using pulsed laser ablation, adopting the vapor-liquid-solid (VLS) growth mechanism. The GaN nanowires are obtained based on the principle that a catalyst is required to initiate the nanowires growth. Locations of the GaN nanowires are patterned using femtosecond laser and focused ion beam. Scanning electron microscopy (SEM) is used to characterize the nanowires. This patterning of GaN nanowires will enable selective growth of nanowires and bottom-up assembly of integrated electronic and photonic devices.

  9. Gallium-67 myocardial imaging for the detection of bacterial endocarditis

    Energy Technology Data Exchange (ETDEWEB)

    Wiseman, J.; Rouleau, J.; Rigo, P.; Strauss, H.W.; Pitt, B.

    1976-07-01

    Eleven patients with a clinical diagnosis of bacterial endocarditis underwent scintillation scanning of the precordial region 2--7 days after the intravenous administration of 3 mCi of gallium-67 citrate. Seven had positive scans, 3 of which were confirmed by postmortem imaging at autopsy. Serial images revealed the scans to be frequently negative at 48 hours and positive from 3 to 8 days following injection. Uptake was not seen in the region of the myocardium 48 hours or longer after the injection of 15 patients without endocarditis used as controls.

  10. Control of Surface Attack by Gallium Alloys in Electrical Contacts.

    Science.gov (United States)

    1986-03-28

    and atmospheric control but does not allow visual observation of the contact brushes. This machine is a small homopolar motor built from mild steel...collectors,gallium, homopolar devices,liquid metals,~- is. ABSTRACT ICNI.. .. w 41N"w -~dv.mp.d Wrllt by Itabata" * Electrical contact between a copp’er...32 5 Test rig with felt metal brushes 32 6 Homopolar test apparatus 33 7 Rewetting of alloy track 33 8 Alloy track after running with finger 34 brushes

  11. Catalytic behavior of gallium-containing mesoporous silicas

    Directory of Open Access Journals (Sweden)

    K. Bachari

    2017-02-01

    Full Text Available The vapor phase tert-butylation of anisole with tert-butanol reaction has been inspected over a series of Ga-FSM-16 with different Si/Ga ratios = 75, 35, 5 synthesized by intercalating kanemite using cetyltrimethylammonium bromide (CTMABr and gallium nitrate. The resulting samples were characterized by means of inductively coupled plasma (ICP technique, BET, BJH, XRD and a temperature–programed–desorption (TPD of pyridine. In addition, the influence of molar ratio, influence of temperature, weight hourly space velocity (WHSV and time on stream on the selectivity of products was investigated and the results are discussed.

  12. Selective growth of gallium nitride nanowires by femtosecond laser patterning

    International Nuclear Information System (INIS)

    Ng, D.K.T.; Hong, M.H.; Tan, L.S.; Zhou, Y.; Chen, G.X.

    2008-01-01

    We report on gallium nitride (GaN) nanowires grown using pulsed laser ablation, adopting the vapor-liquid-solid (VLS) growth mechanism. The GaN nanowires are obtained based on the principle that a catalyst is required to initiate the nanowires growth. Locations of the GaN nanowires are patterned using femtosecond laser and focused ion beam. Scanning electron microscopy (SEM) is used to characterize the nanowires. This patterning of GaN nanowires will enable selective growth of nanowires and bottom-up assembly of integrated electronic and photonic devices

  13. Photo-dissociation of hydrogen passivated dopants in gallium arsenide

    International Nuclear Information System (INIS)

    Tong, L.; Larsson, J.A.; Nolan, M.; Murtagh, M.; Greer, J.C.; Barbe, M.; Bailly, F.; Chevallier, J.; Silvestre, F.S.; Loridant-Bernard, D.; Constant, E.; Constant, F.M.

    2002-01-01

    A theoretical and experimental study of the photo-dissociation mechanisms of hydrogen passivated n- and p-type dopants in gallium arsenide is presented. The photo-induced dissociation of the Si Ga -H complex has been observed for relatively low photon energies (3.48 eV), whereas the photo-dissociation of C As -H is not observed for photon energies up to 5.58 eV. This fundamental difference in the photo-dissociation behavior between the two dopants is explained in terms of the localized excitation energies about the Si-H and C-H bonds

  14. Liquid phase epitaxy of gallium arsenide - a review

    International Nuclear Information System (INIS)

    Alexiev, D.; Edmondson, M.; Butcher, K.S.A.; Tansley, T.

    1992-07-01

    Liquid phase epitaxy of gallium arsenide has been investigated intensively from the late 1960's to the present and has now a special place in the manufacture of wide band, compound semiconductor radiation detectors. Although this particular process appears to have gained prominence in the last three decades, the authors point out that its origins reach back to 1836 when Frankenheim made his first observations. A brief review is presented from a semiconductor applications point of view on how this subject developed. 70 refs., 5 figs

  15. Anomalous tensoelectric effects in gallium arsenide tunnel diodes

    Energy Technology Data Exchange (ETDEWEB)

    Alekseeva, Z.M.; Vyatkin, A.P.; Krivorotov, N.P.; Shchegol' , A.A.

    1988-02-01

    Anomalous tensoelectric phenomena induced in a tunnel p-n junction by a concentrated load and by hydrostatic compression were studied. The anomalous tensoelectric effects are caused by the action of concentrators of mechanical stresses in the vicinity of the p-n junction, giving rise to local microplastic strain. Under the conditions of hydrostatic compression prolate inclusions approx.100-200 A long play the role of concentrators. Analysis of irreversible changes in the current-voltage characteristics of tunnel p-n junctions made it possible to separate the energy levels of the defects produced with plastic strain of gallium arsenide.

  16. Gallium uptake in tryptophan-related pulmonary disease

    International Nuclear Information System (INIS)

    Kim, S.M.; Park, C.H.; Intenzo, C.M.; Patel, R.

    1991-01-01

    We describe a patient who developed fever, fatigue, muscle weakness, dyspnea, skin rash, and eosinophilia after taking high doses of tryptophan for insomnia for two years. A gallium-67 scan revealed diffuse increased uptake in the lung and no abnormal uptake in the muscular distribution. Bronchoscopy and biopsy confirmed inflammatory reactions with infiltration by eosinophils, mast cells, and lymphocytes. CT scan showed an interstitial alveolar pattern without fibrosis. EMG demonstrated diffuse myopathy. Muscle biopsy from the right thigh showed an inflammatory myositis with eosinophilic and lymphocytic infiltrations

  17. Gallium-67 myocardial imaging for the detection of bacterial endocarditis

    International Nuclear Information System (INIS)

    Wiseman, J.; Rouleau, J.; Rigo, P.; Strauss, H.W.; Pitt, B.

    1976-01-01

    Eleven patients with a clinical diagnosis of bacterial endocarditis underwent scintillation scanning of the precordial region 2--7 days after the intravenous administration of 3 mCi of gallium-67 citrate. Seven had positive scans, 3 of which were confirmed by postmortem imaging at autopsy. Serial images revealed the scans to be frequently negative at 48 hours and positive from 3 to 8 days following injection. Uptake was not seen in the region of the myocardium 48 hours or longer after the injection of 15 patients without endocarditis used as controls

  18. Ultrafast photocurrents and terahertz radiation in gallium arsenide and carbon based nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Prechtel, Hans Leonhard

    2011-08-15

    of about hundred picoseconds. Furthermore, we showed that in optically pumped graphene electromagnetic radiation up to 1THz is generated. We also investigated the time-integrated photocurrent and photoconductance processes of suspended p-doped gallium arsenide nanowires contacted by a focused ion beam deposition technique. The observed photocurrent is generated at the Schottky contacts between the nanowire and metal source-drain electrodes, while the observed photoconductance signal can be explained by a photogating effect induced by optically generated charge carriers located at the surface of the nanowire. Both optoelectronic effects are sensitive to the polarization of the exciting laser field. We furthermore studied the time-resolved photocurrent dynamics of p- doped gallium arsenide nanowires lying on a sapphire substrate and contacted by optical lithography. In the experiments we were able to resolve displacement currents, transport currents of holes, as well as carrier lifetime limited currents. We were able to spatially relate the time-integrated measurements to the time-resolved measurements. We discovered that the time-integrated measurements are dominated by a transport current, which is limited by the recombination lifetime of photo electrons and holes in the GaAs nanowire. The data further suggested that a photo-thermoelectric current is generated in the nanowires for excitation close to the contacts. There, we found a photocurrent with an exponential decay of only a few picoseconds. (orig.)

  19. Gallium nitride based thin films for photon and particle radiation dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Hofstetter, Markus

    2012-07-23

    Ionization chambers have been used since the beginning of the 20th century for measuring ionizing radiation and still represent the ''gold standard'' in dosimetry. However, since the sensitivity of the devices is proportional to the detection volume, ionization chambers are not common in numerous medical applications, such as imaging. In these fields, spatially resolved dose information is, beside film-systems, usually measured with scintillators and photo-multipliers, which is a relatively complex and expensive technique. For thus much effort has been focused on the development of novel detection systems in the last decades and especially in the last few years. Examples include germanium or silicon photoconductive detectors, MOSFETs, and PIN-diodes. Although for these systems, miniaturization for spatially resolved detection is possible, they suffer from a range of disadvantages. Characteristics such as poor measurement stability, material degradation, and/or a limited measurement range prevent routine application of these techniques in medical diagnostic devices. This work presents the development and evaluation of gallium nitride (GaN) thin films and heterostructures to validate their application in x-ray detection in the medical regime. Furthermore, the impact of particle radiation on device response was investigated. Although previous publications revealed relatively low energy absorption of GaN, it is possible to achieve very high signal amplification factors inside the material due to an appropriate sensor configuration, which, in turn, compensates the low energy absorption. Thus, gallium nitride can be used as a photo-conductor with ohmic contacts. The conductive volume of the sensor changes in the presence of external radiation, which results in an amplified measurement signal after applying a bias voltage to the device. Experiments revealed a sensitivity of the device between air kerma rates of 1 {mu}Gy/s and 20 mGy/s. In this range

  20. Gallium-67 citrate imaging in underground coal miners

    International Nuclear Information System (INIS)

    Kanner, R.E.; Barkman, H.W. Jr.; Rom, W.N.; Taylor, A.T. Jr.

    1985-01-01

    Twenty-two underground coal workers with 27 or more years of coal dust exposure were studied with gallium-67 citrate (Ga-67) imaging. Radiographic evidence of coal workers indicates that pneumoconiosis (CWP) was present in 12 subjects. The Ga-67 scan was abnormal in 11 of 12 with, and 9 of 10 without, CWP. The Ga-67 uptake index was significantly correlated with total dust exposure (p less than 0.01) and approached significant correlation with the radiographic profusion of the nodules (0.10 greater than p greater than 0.05). There was no correlation between Ga-67 uptake and spirometric function, which was normal in this group of patients; furthermore, increased lung uptake of gallium did not indicate a poor prognosis in subjects no longer exposed to coal dust. While coal dust exposure may be associated with positive Ga-67 lung scan in coal miners with many years of coal dust exposure, the scan provided no information not already available from a careful exposure history and a chest radiograph. Since Ga-67 scanning is a relatively expensive procedure the authors would recommend that its use in subjects with asymptomatic CWP be limited to an investigative role and not be made part of a routine evaluation

  1. Value of gallium 67 citrate scintigraphy in ophthalmology

    International Nuclear Information System (INIS)

    Ivanez-Alloschery, Monique.

    1978-01-01

    For ophthalmologists scintigraphy appears as a simple method to detect endoocular or endoorbital abnormalities. However none of the many scintigraphic methods described seems reliable enough to be used alone. One of the latest isotopic explorations using gallium 67 citrate, a tracer considered tumour-tropic might be able to solve this problem. The aim of this work is to judge the value of the method in the diagnosis of malignant endoocular and endoorbital tumours on the basis of 24 anatomoclinical observations. It may be concluded from this study that ocular gallium 67 citrate scintigraphy, which gave no clearly positive results at all but some doubtful results in the case of endoocular tumours more than 5 mm in diameter, is to be rejected; fluorescein angiography and ocular echograhy provide more elements for an accurate etiological diagnosis. Orbital scintigraphy on the other hand seems to be a necessary complement to a tomodensitometric examination since both methods offer diagnostic information without systematic recurse to carotid arteriography or orbital phlebography, sometimes dangerous for the patient [fr

  2. Gallium-67 scintiscanning of the lungs of AIDS patients

    International Nuclear Information System (INIS)

    Tatsch, K.; Knesewitsch, P.; Kirsch, C.M.; Kueffer, G.; Doerner, G.; Goebel, F.D.

    1988-01-01

    Thirty patients suffering from AIDS have been examined in this study. The stage of infection of the patients was defined according to the criteria of the Center for Disease Control, so that the study covered 22 patients with manifest AIDS, and 8 patients with AIDS-related complex. The lung scans have been made in all patients 48 and 72 hours after i.v. injection of 185 MBq of 67 Ga citrate, taking ventral and dorsal images with the gamma camera. In the scans recorded after 72 hours, ROI technique has been used to quantify the lung uptake and to put it in relation to uptake data of the soft neck tissue. The results show that gallium scintiscanning is far more sensitive in detecting opportunistic pneumonia in AIDS patients than is conventional chest radiography. If the latter detected any signs at all, the gallium scan did so about one to two weeks earlier in about one third of the patients. Pathologic accumulation in the scintiscan exceeding the range shown by the correlated radiograph indicate that in single cases extension of pneumonia can be underestimated when assessed by the radiograph alone. (orig./MG) [de

  3. Macroscopic diffusion models for precipitation in crystalline gallium arsenide

    Energy Technology Data Exchange (ETDEWEB)

    Kimmerle, Sven-Joachim Wolfgang

    2009-09-21

    Based on a thermodynamically consistent model for precipitation in gallium arsenide crystals including surface tension and bulk stresses by Dreyer and Duderstadt, we propose two different mathematical models to describe the size evolution of liquid droplets in a crystalline solid. The first model treats the diffusion-controlled regime of interface motion, while the second model is concerned with the interface-controlled regime of interface motion. Our models take care of conservation of mass and substance. These models generalise the well-known Mullins- Sekerka model for Ostwald ripening. We concentrate on arsenic-rich liquid spherical droplets in a gallium arsenide crystal. Droplets can shrink or grow with time but the centres of droplets remain fixed. The liquid is assumed to be homogeneous in space. Due to different scales for typical distances between droplets and typical radii of liquid droplets we can derive formally so-called mean field models. For a model in the diffusion-controlled regime we prove this limit by homogenisation techniques under plausible assumptions. These mean field models generalise the Lifshitz-Slyozov-Wagner model, which can be derived from the Mullins-Sekerka model rigorously, and is well understood. Mean field models capture the main properties of our system and are well adapted for numerics and further analysis. We determine possible equilibria and discuss their stability. Numerical evidence suggests in which case which one of the two regimes might be appropriate to the experimental situation. (orig.)

  4. Sputter deposited gallium doped ZnO for TCO applications

    Energy Technology Data Exchange (ETDEWEB)

    Dietrich, Marc; Kronenberger, Achim; Polity, Angelika; Meyer, Bruno [I. Physikalisches Institut, Justus Liebig Universitaet Giessen (Germany); Blaesing, Juergen; Krost, Alois [FNW/IEP/AHE, Otto-von-Guericke Universitaet Magdeburg (Germany)

    2010-07-01

    Transparent conducting oxides to be used for flat panel or display applications should exhibit low electrical resistivity in line with a high optical transmission in the visible spectral range. Today indium-tin-oxide is the material which meets these requirements best. However, the limited availability of indium makes it useful to search for alternatives and ZnO doped with group III elements are promising candidates. While the Al doping in high concentrations causes problems due to the formation of insulating Al-oxides, Gallium related oxides are typically n-type conducting wide band gap semiconductors. Therefore we deposited Gallium doped ZnO thin films on quartz and sapphire substrates by radio frequency magnetron sputtering with a ZnO/Ga{sub 2}O{sub 3}(3at%) composite target. The substrate temperature and the oxygen flow during the sputtering process were varied to optimise the layer properties. Introducing oxygen to the sputtering gas allowed to vary the resistivity of the films by three orders of magnitude from about 1 {omega}cm down to less than 1 m{omega}cm.

  5. Mechanisms of thermal induced gallium removal (TIGR) from plutonium dioxide. Revision 1

    International Nuclear Information System (INIS)

    DeMuth, S.F.

    1998-01-01

    This study was initiated in order to determine the advantages of using a mixed-bed rather than a fixed-bed reactor (i.e. furnace) for separation of gallium from PuO 2 by the Thermal Induced Gallium Removal (TIGR) process. The TIGR process is based upon vaporization of gallium suboxide (Ga 2 O). from essentially nonvolatile PuO 2 . The gallium suboxide is formed by passing a reducing gas (i.e. hydrogen) over the PuO 2 particles. Several mechanisms are involved in the reduction and convective vaporization of the gallium suboxide. If the mass transfer of the gallium suboxide across the solid to gas interface significantly affects the processing time, it may be advantageous to use a mixed-bed reactor rather than a fixed-bed reactor. However, due to the difficulty of handling PuO 2 powder, a mixed-bed reactor should be used only if significant advantages can be demonstrated. Based on available data, the results of this study provide strong evidence that a mixed-bed reactor (i.e. furnace) would provide little advantage over a fixed-bed reactor. This is due to the conclusion that the mechanism of internal gallium diffusion within the particle has the predominant affect on the processing time. This is an important conclusion since the use of a mixed-bed would require development of more complex hardware than for a fixed-bed

  6. Technetium-99m DTPA aerosol and gallium scanning in acquired immune deficiency syndrome

    International Nuclear Information System (INIS)

    Picard, C.; Meignan, M.; Rosso, J.; Cinotti, L.; Mayaud, C.; Revuz, J.

    1987-01-01

    In 11 non-smoking AIDS patients suspected of pneumocystis carinii pneumonia (PCP), the results of Tc-99m DTPA aerosol clearances, gallium scans, and arterial blood gases were compared with those of bronchoalveolar lavage (BAL). Nine patients had PCP. All had increased clearances five times higher than the normal (5.6 +/- 2.3% X min-1 vs 1.1 +/- 0.34% X min-1, N = 10, P less than 0.001), suggesting an increased alveolar permeability. Gallium scans were abnormal in six patients but normal or slightly abnormal in the three others. Four of these nine patients had normal chest x-rays. In two of these the gallium scan was abnormal, but in the two others, only the increased Tc-99m DTPA clearances showed evidence of lung disease. Two patients had normal BAL, with normal clearances and gallium scans. Four out of the nine patients with PCP were studied after treatment. Three recovered and had normal clearance and gallium scans. One still had PCP with increased clearance but normal gallium scan. Gallium scanning and Tc-99m DTPA clearance are useful for detecting lung disease in AIDS patients with suspected PCP and for prompting BAL when chest x-rays and PaO 2 levels are normal. Due to its high sensitivity, a normal Tc-99m DTPA clearance could avoid BAL

  7. Gallium-67 uptake by the thyroid associated with progressive systemic sclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Sjoberg, R.J.; Blue, P.W.; Kidd, G.S.

    1989-01-01

    Although thyroidal uptake of gallium-67 has been described in several thyroid disorders, gallium-67 scanning is not commonly used in the evaluation of thyroid disease. Thyroidal gallium-67 uptake has been reported to occur frequently with subacute thyroiditis, anaplastic thyroid carcinoma, and thyroid lymphoma, and occasionally with Hashimoto's thyroiditis and follicular thyroid carcinoma. A patient is described with progressive systemic sclerosis who, while being scanned for possible active pulmonary involvement, was found incidentally to have abnormal gallium-67 uptake only in the thyroid gland. Fine needle aspiration cytology of the thyroid revealed Hashimoto's thyroiditis. Although Hashimoto's thyroiditis occurs with increased frequency in patients with progressive systemic sclerosis, thyroidal uptake of gallium-67 associated with progressive systemic sclerosis has not, to our knowledge, been previously described. Since aggressive thyroid malignancies frequently are imaged by gallium-67 scintigraphy, fine needle aspiration cytology of the thyroid often is essential in the evaluation of thyroidal gallium-67 uptake.

  8. The Knight shift in liquid gallium confined within porous glasses and opals

    International Nuclear Information System (INIS)

    Charnaya, E V; Michel, D; Tien, C; Kumzerov, Yu A; Yaskov, D

    2003-01-01

    71 Ga nuclear magnetic resonance studies were carried out for liquid gallium embedded into porous glasses with different pore sizes and into artificial opals within the temperature range from about 320 K to complete confined gallium freezing. A general decrease in the Knight shift compared to the bulk melt depending on pore sizes was observed in contrast to theoretical predictions. Correlations between alterations in the Knight shift and pore sizes were established for particular pore geometry. It was also observed that confined geometry affects the temperature dependence of the Knight shift in liquid gallium

  9. Potentiometric end point detection in the EDTA titrimetric determination of gallium

    International Nuclear Information System (INIS)

    Gopinath, N.; Renuka, M.; Aggarwal, S.K.

    2001-01-01

    Gallium is titrated in presence of known amount of Fe (III) with EDTA in HNO 3 solution at pH 2 to 3. The end point is detected potentiometrically employing a bright platinum wire - saturated calomel (SCE) reference electrode system, the redox couple being Fe (III) / Fe (II). Since Fe (III) is also titrated by EDTA, it is, therefore, subtracted from titre value to get the EDTA equivalent to gallium only. Precision and accuracy 0.2 to 0.4% was obtained in the results of gallium in the range of 8 to 2 mg. (author)

  10. Clinical evaluation of gallium-67 scintigraphy in comparison with autopsy findings in the older ages

    International Nuclear Information System (INIS)

    Shimohara, Yasuaki; Tanno, Munehiko; Yamada, Hideo; Kimura, Yuji; Nishino, Hideo; Ide, Hiroshi; Kurihara, Norimitsu; Chiba, Kazuo.

    1987-01-01

    A correlative study of autopsy findings and retrospective review of gallium scintigrams were performed in 106 older ages cases. Of these cases studied, 57 % demonstrated positive gallium study in the present series. Histological correlation was undertaken in cases of lung cancer. Among them, squamous cell carcinoma showed the highest incidence of positive results (83 %), whereas adenocarcinoma was the lowest (35 %). There is no apparent correlation between subtypes of histological classification of adenocarcinoma and abnormal accumulation of gallium. However, abnormal accumulation of the nuclide seems to be rather related with interstitial reactions, namely fibrotic changes, lymphocyte infiltration and vascularization. (author)

  11. Gallium-67 detection of intramammary injection sites secondary to intravenous drug abuse

    International Nuclear Information System (INIS)

    Swayne, L.C.

    1989-01-01

    A case of gallium localization within the breast occurred secondary to intravenous drug abuse. In the appropriate clinical setting, prior self-administered injections should be considered as a cause of Ga-67 accumulation at unusual sites

  12. Does gallium uptake in the pulmonary hila predict involvement by non-Hodgkin's lymphoma?

    International Nuclear Information System (INIS)

    Champion, P.E.; Groshar, D.; Hooper, H.R.; Palmer, M.; Catz, Z.; Belch, A.; McEwan, A.

    1992-01-01

    67 Ga imaging of non-Hodgkin's lymphoma is useful for evaluating the presence of viable tumour in a residual mass after treatment. However, we have frequently seen gallium uptake in the pulmonary hila without other evidence of lymphoma. To study the significance of this finding, 79 patients with intermediate grade non-Hodgkin's lymphoma were reviewed. Thirty-seven (47%) had abnormal hilar gallium uptake. Twenty-three of these could be fully evaluated, and only five (22%) had hilar lymphoma. A pattern of bilateral, symmetric hilar uptake was seen in 19 patients, but only one had evidence of lymphoma. In 15 cases, this pattern was seen only on single photon emission computed tomography (SPECT). The aetiology of this uptake remains unknown. It is not treatment related, as 12 patients had hilar gallium uptake prior to chemotherapy. Unless confirmed by other methods, hilar gallium uptake should not be attributed to lymphoma, and should not influence patient management. (Author)

  13. Optical and Micro-Structural Characterization of MBE Grown Indium Gallium Nitride Polar Quantum Dots

    KAUST Repository

    El Afandy, Rami

    2011-01-01

    Gallium nitride and related materials have ushered in scientific and technological breakthrough for lighting, mass data storage and high power electronic applications. These III-nitride materials have found their niche in blue light emitting diodes

  14. Gallium Content in PuO2 Using Laser Induced Breakdown Spectroscopy (LIBS)

    International Nuclear Information System (INIS)

    Smith, C.A.; Martinez, M.A.; Veirs, D.K.

    1999-01-01

    Laser Induced Breakdown Spectroscopy (LIBS) has been applied to the semi-quantitative analysis of gallium in plutonium oxide at the Los Alamos Plutonium Facility. The oxide samples were generated by the Thermally Induced Gallium Removal (TIGR) process, a pretreatment step prior to MOX fuel processing. The TIGR process uses PuO 2 containing 1 wt% gallium (nominal) as feed material. Following the TIGR process, gallium content was analyzed by LIBS and also by conventional wet chemical analysis (ICP-MS). Although the data range was insufficient to obtain an adequate calibration, general agreement between the two techniques was good. LIBS was found to have a useful analytical range of 34-400 ppm for Ga in PuO 2

  15. Radiology of pulmonary disease. Chest radiography, computed tomography, and gallium scanning

    International Nuclear Information System (INIS)

    Golden, J.A.; Sollitto, R.A.

    1988-01-01

    A review of the radiologic manifestations of AIDS pulmonary diseases, with an emphasis on the utility of gallium scanning in the context of the normal or equivocal chest x-ray, is presented.99 references

  16. LETTER TO THE EDITOR: Fabrication and structure of an opal-gallium nitride nanocomposite

    Science.gov (United States)

    Davydov, V. Yu; Dunin-Borkovski, R. E.; Golubev, V. G.; Hutchison, J. L.; Kartenko, N. F.; Kurdyukov, D. A.; Pevtsov, A. B.; Sharenkova, N. V.; Sloan, J.; Sorokin, L. M.

    2001-02-01

    A three-dimensional gallium nitride lattice has been synthesized within the void sublattice of an artificial opal. The composite structure has been characterized using X-ray diffraction, Raman spectroscopy and transmission electron microscopy.

  17. Abnormal gallium scan patterns of the salivary gland in pulmonary sarcoidosis

    Energy Technology Data Exchange (ETDEWEB)

    Mishkin, F.S.; Tanaka, T.T.; Niden, A.H.

    1978-12-01

    The findings of gallium imaging suggest that parotid abnormalities in sarcoidosis are common. Correlation with lung and mediastinal uptake suggests that this represents an early disease state and that it responds to steroid administration. That the findings after therapy do not simply represent suppression of the uptake mechanism for gallium is supported by objective improvement in pulmonary function as well as symptomatic relief. Salivary gland accumulation of gallium citrate occurred in one third of our control group patients--in those who had collagen disease and presumably either were alcoholic or had infectious parotitis. This may also be seen in lymphoma and after radiation therapy. Although the combination of salivary gland, pulmonary, and hilar concentration of gallium is not specific, in the appropriate clinical setting the pattern may be helpful in suggesting the correct diagnosis.

  18. Abnormal gallium scan patterns of the salivary gland in pulmonary sarcoidosis

    International Nuclear Information System (INIS)

    Mishkin, F.S.; Tanaka, T.T.; Niden, A.H.

    1978-01-01

    The findings of gallium imaging suggest that parotid abnormalities in sarcoidosis are common. Correlation with lung and mediastinal uptake suggests that this represents an early disease state and that it responds to steroid administration. That the findings after therapy do not simply represent suppression of the uptake mechanism for gallium is supported by objective improvement in pulmonary function as well as symptomatic relief. Salivary gland accumulation of gallium citrate occurred in one third of our control group patients--in those who had collagen disease and presumably either were alcoholic or had infectious parotitis. This may also be seen in lymphoma and after radiation therapy. Although the combination of salivary gland, pulmonary, and hilar concentration of gallium is not specific, in the appropriate clinical setting the pattern may be helpful in suggesting the correct diagnosis

  19. Micro-Scale Gallium Nitride Pressure Sensors for Advanced Harsh Environment Space Technology

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this research is to study the high-temperature response of the 2-dimesional electron gas (2DEG) that occurs at the interface of aluminum gallium nitride...

  20. Importance of gallium-67 scintigraphy in primary cutaneous B-cell lymphoma: report of two cases

    International Nuclear Information System (INIS)

    Attab, Cyomara Sanches; Moriguchi, Sonia Marta; Rocha, Euclides Timoteo da

    2010-01-01

    The authors describe two cases of cutaneous B-cell lymphoma where correct staging, treatment and follow-up could be achieved through a combination of conventional imaging studies and gallium-67 scintigraphy. (author)

  1. Targeted Delivery of Glucan Particle Encapsulated Gallium Nanoparticles Inhibits HIV Growth in Human Macrophages

    Directory of Open Access Journals (Sweden)

    Ernesto R. Soto

    2016-01-01

    Full Text Available Glucan particles (GPs are hollow, porous 3–5 μm microspheres derived from the cell walls of Baker’s yeast (Saccharomyces cerevisiae. The 1,3-β-glucan outer shell provides for receptor-mediated uptake by phagocytic cells expressing β-glucan receptors. GPs have been used for macrophage-targeted delivery of a wide range of payloads (DNA, siRNA, protein, small molecules, and nanoparticles encapsulated inside the hollow GPs or bound to the surface of chemically derivatized GPs. Gallium nanoparticles have been proposed as an inhibitory agent against HIV infection. Here, macrophage targeting of gallium using GPs provides for more efficient delivery of gallium and inhibition of HIV infection in macrophages compared to free gallium nanoparticles.

  2. Radiation dose estimates for the fetus from intakes of gallium citrate by the mother

    International Nuclear Information System (INIS)

    Watson, E.E.

    1992-01-01

    Information about the distribution and retention of Ga 67 in the pregnant woman is limited and must be extrapolated from animal data. Studies have shown that gallium administered as citrate crosses the placenta into the fetus; however, the concentration in the placenta appears to be considerably greater than that in the fetus. Little is known about the retention of gallium in the fetus and placenta. In this paper, available data on the concentrations in the placenta and fetus are combined with data on the biokinetics of gallium in the woman to provide a model for dose calculation. The absorbed fractions calculated from the pregnant woman models developed by the Radiopharmaceutical Internal Dose Information Center will be used to provide dose estimates for the radioisotopes of gallium. (author)

  3. Feasibility of flooding the reactor cavity with liquid gallium coolant for IVR-ERVC strategy

    International Nuclear Information System (INIS)

    Park, Seong Dae; Bang, In Cheol

    2013-01-01

    Highlights: ► We investigate the feasibility of gallium liquid metal application for IVR-ERVC. ► We consider overall concerns to apply the liquid metal. ► Decay heat can be removed by flooding the reactor cavity with gallium liquid metal. -- Abstract: In this paper, a new approach replacing the ERVC coolant by a liquid metal instead of water is studied to avoid the heat removal limit of CHF during boiling of water. As the flooding material, gallium is used in terms of the melting and boiling points. Gallium has the enough low melting point of ∼29.7 °C to ensure to maintain liquid state within the containment building. A gallium storage tank for the new flooding system of the ERVC is located in higher position than one of the reactor cavity to make a passive system using the gravity for the event of a station blackout (SBO). While the decay heat from the reactor vessel is removed by gallium, the borated water which is coming out from the reactor system plays a role as the ultimate heat sink in this ERVC system. In the system, two configurations of gallium and borated water are devised depending on whether the direct contact between them occurs. In the first configuration, two fluids are separated by the block structure. The decay heat is transported from molten corium to gallium through the vessel wall. Then the heat is ultimately dissipated by boiling of water in the block structure surface facing the borated water. In the second configuration, the cavity is flooded with both borated water and gallium in the same reactor cavity space. As the result, two layers of the fluids are naturally formed by the density difference. Like the first configuration, finally the heat removal is achieved by boiling of water via gallium. The CFD analysis shows that the maximum temperature of gallium is much lower than its boiling point while the natural circulation is stably formed in two types of the configurations without any serious risk of thermal limit

  4. Solar cells with gallium phosphide/silicon heterojunction

    Science.gov (United States)

    Darnon, Maxime; Varache, Renaud; Descazeaux, Médéric; Quinci, Thomas; Martin, Mickaël; Baron, Thierry; Muñoz, Delfina

    2015-09-01

    One of the limitations of current amorphous silicon/crystalline silicon heterojunction solar cells is electrical and optical losses in the front transparent conductive oxide and amorphous silicon layers that limit the short circuit current. We propose to grow a thin (5 to 20 nm) crystalline Gallium Phosphide (GaP) by epitaxy on silicon to form a more transparent and more conducting emitter in place of the front amorphous silicon layers. We show that a transparent conducting oxide (TCO) is still necessary to laterally collect the current with thin GaP emitter. Larger contact resistance of GaP/TCO increases the series resistance compared to amorphous silicon. With the current process, losses in the IR region associated with silicon degradation during the surface preparation preceding GaP deposition counterbalance the gain from the UV region. A first cell efficiency of 9% has been obtained on ˜5×5 cm2 polished samples.

  5. Synchrotron white beam topographic studies of gallium arsenide crystals

    International Nuclear Information System (INIS)

    Wierzchowski, W.; Wieteska, K.; Graeff, W.

    1997-01-01

    A series of samples cut out from different types of gallium arsenide crystals with low dislocation density were studied by means of white beam synchrotron topography. The investigation was performed with transmission and black-reflection projection methods and transmission section method. Some of topographs in transmission geometry provided a very high sensitivity suitable for revealing small precipitates. The transmission section images significantly differed depending on the wavelength and absorption. In some cases a distinct Pendelloesung fringes and fine details of dislocation and precipitates images were observed. It was possible to reproduce the character of these images by means of numerical simulation based on integration of Takagi-Taupin equations. Due to more convenient choice of radiation, synchrotron back-reflection projection topography provided much better visibility of dislocations than analogous realized with conventional X-ray sources. (author)

  6. Localized surface phonon polariton resonances in polar gallium nitride

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Kaijun, E-mail: kfeng@nd.edu; Islam, S. M.; Verma, Jai; Hoffman, Anthony J. [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Streyer, William; Wasserman, Daniel [Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801 (United States); Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); School of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14850 (United States)

    2015-08-24

    We demonstrate the excitation of localized surface phonon polaritons in an array of sub-diffraction pucks fabricated in an epitaxial layer of gallium nitride (GaN) on a silicon carbide (SiC) substrate. The array is characterized via polarization- and angle-dependent reflection spectroscopy in the mid-infrared, and coupling to several localized modes is observed in the GaN Reststrahlen band (13.4–18.0 μm). The same structure is simulated using finite element methods and the charge density of the modes are studied; transverse dipole modes are identified for the transverse electric and magnetic polarizations and a quadrupole mode is identified for the transverse magnetic polarization. The measured mid-infrared spectrum agrees well with numerically simulated spectra. This work could enable optoelectronic structures and devices that support surface modes at mid- and far-infrared wavelengths.

  7. Microstructures of group III-nitrides after implantation with gallium

    International Nuclear Information System (INIS)

    Kench, P.J.

    2001-05-01

    High doses of gallium have been implanted into layers of aluminium nitride (AIN), indium nitride (InN) and amorphous silicon nitride (a-SiN x ) in an attempt to bond gallium with nitrogen and form binary or ternary alloys. The microstructure of the resultant layers have been characterised using, principally, transmission electron microscopy and X-ray photoelectron spectroscopy. The implantation of a high dose of Ga ions into AIN was successful in synthesising a GaN/GaAlN compound. The resultant layers were largely uniform but contained aluminium precipitates near the surface. These precipitates were pure Al and were most common in the region associated with the maximum Ga concentration. Deconvolution of X-ray photoelectron spectroscopy peaks indicated that Ga existed in a number of chemical states, including the nitride. Electron diffraction patterns from the implanted layers were closely indexed to both AIN and GaN. A further N implant was used to reduce the concentration of the aluminium precipitates and increase the concentration of GaN bonds. The yield of Ga-N bonds dramatically increased and a reduction in the concentration of Al precipitates was observed. Laser and thermal annealing was performed on the implanted AIN substrates. The near surface regions of the implanted specimens appeared to free of precipitates and bubbles. Laser annealing did have a noticeable effect on the electrical and optical properties of the layers. After laser annealing the conductivity of the Ga implanted layer was lower, indicating that the quality of the material had improved. PL measurements showed that a new PL peak at 2.6 eV appeared after laser annealing. It has been found that implanting InN with gallium can yield Ga-N bonds. However, Ga implants into InN were not as successful at synthesising GaN compounds as those by implanting Ga into AIN, due to the low thermal stability of InN. The implanted InN layers were very irregular and contained large indium precipitates and

  8. 67Gallium citrate lung scans in interstitial lung disease

    International Nuclear Information System (INIS)

    Niden, A.H.; Mishkin, F.S.; Khurana, M.M.L.

    1976-01-01

    Patients with diffuse interstitial lung disease often require a lung biopsy to determine the diagnosis and proper therapy. However, once the diagnosis is established, clinical evaluation of symptoms, chest roentgenogram and pulmonary function testing are the only noninvasive means currently available to assess activity of the disease process and response to the therapy. Although these measures appear adequate in the presence of acute active disease in which response to therapy results in readily demonstrable changes in the above parameters, they may be insensitive to subtle changes that can occur in minimally active disease with slowly progressive interstitial pulmonary fibrosis over a period of years. A more sensitive noninvasive technique for identifying these cases with a smoldering diffuse interstitial inflammatory process might greatly improve our ability to effectively manage such patients. With this in mind, the value of gallium lung scan was investigated to assess its ability to predict inflammatory activity in such a clinical setting

  9. /sup 67/Gallium citrate lung scans in interstitial lung disease

    Energy Technology Data Exchange (ETDEWEB)

    Niden, A.H.; Mishkin, F.S.; Khurana, M.M.L.

    1976-02-01

    Patients with diffuse interstitial lung disease often require a lung biopsy to determine the diagnosis and proper therapy. However, once the diagnosis is established, clinical evaluation of symptoms, chest roentgenogram and pulmonary function testing are the only noninvasive means currently available to assess activity of the disease process and response to the therapy. Although these measures appear adequate in the presence of acute active disease in which response to therapy results in readily demonstrable changes in the above parameters, they may be insensitive to subtle changes that can occur in minimally active disease with slowly progressive interstitial pulmonary fibrosis over a period of years. A more sensitive noninvasive technique for identifying these cases with a smoldering diffuse interstitial inflammatory process might greatly improve our ability to effectively manage such patients. With this in mind, the value of gallium lung scan was investigated to assess its ability to predict inflammatory activity in such a clinical setting.

  10. Development of microwave amplifier based on gallium nitride semiconductor structures

    International Nuclear Information System (INIS)

    Pavlov, D.Yi.; Prokopenko, O.V.; Tsvyirko, Yu.A.; Pavlov, Yi.L.

    2014-01-01

    Microwave properties of microwave amplifier based on gallium nitride (GN) semiconductor structures has been calculated numerically. We proposed the method of numerical calculation of device. This method is accurately sets the value of its characteristics depending on the elements that are used in design of amplifier. It is shown that the device based on GN HEMT-transistors could have amplification factor about 50 dB, while its sizes are 27x18x5.5 mm 3 . Also was provided the absolute stability an amplifier in the whole operating frequency range. It is quite important when using this type of amplifiers in different conditions of exploitation and various fields of use the radioelectronic equipment

  11. Amorphous gallium oxide grown by low-temperature PECVD

    KAUST Repository

    Kobayashi, Eiji

    2018-03-02

    Owing to the wide application of metal oxides in energy conversion devices, the fabrication of these oxides using conventional, damage-free, and upscalable techniques is of critical importance in the optoelectronics community. Here, the authors demonstrate the growth of hydrogenated amorphous gallium oxide (a-GaO:H) thin-films by plasma-enhanced chemical vapor deposition (PECVD) at temperatures below 200 °C. In this way, conformal films are deposited at high deposition rates, achieving high broadband transparency, wide band gap (3.5-4 eV), and low refractive index (1.6 at 500 nm). The authors link this low refractive index to the presence of nanoscale voids enclosing H, as indicated by electron energy-loss spectroscopy. This work opens the path for further metal-oxide developments by low-temperature, scalable and damage-free PECVD processes.

  12. A high open-circuit voltage gallium nitride betavoltaic microbattery

    International Nuclear Information System (INIS)

    Cheng, Zaijun; Chen, Xuyuan; San, Haisheng; Feng, Zhihong; Liu, Bo

    2012-01-01

    A high open-circuit voltage betavoltaic microbattery based on a gallium nitride (GaN) p–i–n homojunction is demonstrated. As a beta-absorbing layer, the low electron concentration of the n-type GaN layer is achieved by the process of Fe compensation doping. Under the irradiation of a planar solid 63 Ni source with activity of 0.5 mCi, the open-circuit voltage of the fabricated microbattery with 2 × 2 mm 2 area reaches as much as 1.64 V, which is the record value reported for betavoltaic batteries with 63 Ni source, the short-circuit current was measured as 568 pA and the conversion effective of 0.98% was obtained. The experimental results suggest that GaN is a high-potential candidate for developing the betavoltaic microbattery. (paper)

  13. Phosphorus Dimerization in Gallium Phosphide at High Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Lavina, Barbara [High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154, United States; Department of Physics and Astronomy, University of Nevada, Las Vegas, Nevada 89154, United States; Kim, Eunja [Department of Physics and Astronomy, University of Nevada, Las Vegas, Nevada 89154, United States; Cynn, Hyunchae [Lawrence Livermore National Laboratory, Livermore, California 94550, United States; Weck, Philippe F. [Sandia National Laboratories, Albuquerque, New Mexico 87185, United States; Seaborg, Kelly [High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154, United States; Department of Physics and Astronomy, University of Nevada, Las Vegas, Nevada 89154, United States; Siska, Emily [High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154, United States; Meng, Yue [HPCAT, Carnegie Institution of Washington, Argonne, Illinois 60439, United States; Evans, William [Lawrence Livermore National Laboratory, Livermore, California 94550, United States

    2018-02-09

    Using combined experimental and computational approaches, we show that at 43 GPa and 1300 K gallium phosphide adopts the super-Cmcm structure, here indicated with its Pearson notation oS24. First-principles enthalpy calculations demonstrate that this structure is more thermodynamically stable above ~20 GPa than previously proposed polymorphs. Here, in contrast to other polymorphs, the oS24 phase shows a strong bonding differentiation and distorted fivefold coordination geometries of both P atoms. The shortest bond of the phase is a single covalent P–P bond measuring 2.171(11) Å at synthesis pressure. Phosphorus dimerization in GaP sheds light on the nature of the super-Cmcm phase and provides critical new insights into the high-pressure polymorphism of octet semiconductors. Bond directionality and anisotropy explain the relatively low symmetry of this high-pressure phase.

  14. Recognition of distinctive patterns of gallium-67 distribution in sarcoidosis

    International Nuclear Information System (INIS)

    Sulavik, S.B.; Spencer, R.P.; Weed, D.A.; Shapiro, H.R.; Shiue, S.T.; Castriotta, R.J.

    1990-01-01

    Assessment of gallium-67 ( 67 Ga) uptake in the salivary and lacrimal glands and intrathoracic lymph nodes was made in 605 consecutive patients including 65 with sarcoidosis. A distinctive intrathoracic lymph node 67 Ga uptake pattern, resembling the Greek letter lambda, was observed only in sarcoidosis (72%). Symmetrical lacrimal gland and parotid gland 67 Ga uptake (panda appearance) was noted in 79% of sarcoidosis patients. A simultaneous lambda and panda pattern (62%) or a panda appearance with radiographic bilateral, symmetrical, hilar lymphadenopathy (6%) was present only in sarcoidosis patients. The presence of either of these patterns was particularly prevalent in roentgen Stages I (80%) or II (74%). We conclude that simultaneous (a) lambda and panda images, or (b) a panda image with bilateral symmetrical hilar lymphadenopathy on chest X-ray represent distinctive patterns which are highly specific for sarcoidosis, and may obviate the need for invasive diagnostic procedures

  15. Heterotopic ossification (myositis ossificans) in acquired immune deficiency syndrome. Detection by gallium scintigraphy

    International Nuclear Information System (INIS)

    Drane, W.E.; Tipler, B.M.

    1987-01-01

    A case of heterotopic ossification (myositis ossificans) secondary to the central nervous system complications of acquired immune deficiency syndrome (AIDS) is reported. Because of the overwhelming suspicion of infection in this patient, this diagnosis was not considered until a gallium scan revealed the typical findings of heterotopic ossification. Because of the increasing utilization of gallium imaging in the AIDS population, every imaging specialist should be aware of this potential disorder

  16. Are oral cathartics of value in optimizing the gallium scan. Concise communication

    International Nuclear Information System (INIS)

    Silberstein, E.B.; Fernandez-Ulloa, M.; Hall, J.

    1981-01-01

    The normal intestinal secretion of 9-15% of an administered dose of gallium-67 may prevent early detection of intra-abdominal disease. We randomized 50 patients to receive either no bowel preparation or 30 cc of milk of magnesia plus 5 cc of cascara. No significant difference was found between the two groups in frequency with which gallium interfered with readings or time to complete the study

  17. Are oral cathartics of value in optimizing the gallium scan? Concise communication.

    Science.gov (United States)

    Silberstein, E B; Fernandez-Ulloa, M; Hall, J

    1981-05-01

    The normal intestinal secretion of 9-15% of an administered dose of gallium-67 may prevent early detection of intra-abdominal disease. We randomized 50 patients to receive either no bowel preparation or 30 cc of milk of magnesia plus 5 cc of cascara. No significant difference was found between the two groups in frequency with which gallium interfered with readings or time to complete the study.

  18. Semi-quantitative evaluation of gallium-67 scintigraphy in lupus nephritis

    International Nuclear Information System (INIS)

    Lin Wanyu; Hsieh Jihfang; Tsai Shihchuan; Lan Joungliang; Cheng Kaiyuan; Wang Shyhjen

    2000-01-01

    Within nuclear medicine there is a trend towards quantitative analysis. Gallium renal scan has been reported to be useful in monitoring the disease activity of lupus nephritis. However, only visual interpretation using a four-grade scale has been performed in previous studies, and this method is not sensitive enough for follow-up. In this study, we developed a semi-quantitative method for gallium renal scintigraphy to find a potential parameter for the evaluation of lupus nephritis. Forty-eight patients with lupus nephritis underwent renal biopsy to determine World Health Organization classification, activity index (AI) and chronicity index (CI). A delayed 48-h gallium scan was also performed and interpreted by visual and semi-quantitative methods. For semi-quantitative analysis of the gallium uptake in both kidneys, regions of interest (ROIs) were drawn over both kidneys, the right forearm and the adjacent spine. The uptake ratios between these ROIs were calculated and expressed as the ''kidney/spine ratio (K/S ratio)'' or the ''kidney/arm ratio (K/A ratio)''. Spearman's rank correlation test and Mann-Whitney U test were used for statistical analysis. Our data showed a good correlation between the semi-quantitative gallium scan and the results of visual interpretation. K/S ratios showed a better correlation with AI than did K/A ratios. Furthermore, the left K/S ratio displayed a better correlation with AI than did the right K/S ratio. In contrast, CI did not correlate well with the results of semi-quantitative gallium scan. In conclusion, semi-quantitative gallium renal scan is easy to perform and shows a good correlation with the results of visual interpretation and renal biopsy. The left K/S ratio from semi-quantitative renal gallium scintigraphy displays the best correlation with AI and is a useful parameter in evaluating the disease activity in lupus nephritis. (orig.)

  19. Myocardial scintigraphy with gallium-67 in the detection of cardiac acute rejection

    International Nuclear Information System (INIS)

    Meneguetti, J.C.

    1990-01-01

    In order to evaluate the myocardial scintigraphy with Gallium-67 potentiality in the detection of acute rejection phenomenon, 105 studies were performed in 20 patients after they had a heart transplantation. The scintigraphic images were obtained by a conventional camera-computer system. These images were acquired 48 hours after all the patients were given an intravenous injection of 111 MBq of Gallium-67 Citrate. The biopsies were done according to the Mason technique and the histological analysis followed the Billingham standards. (author)

  20. Gallium nitride-based micro-opto-electro-mechanical systems

    Science.gov (United States)

    Stonas, Andreas Robert

    Gallium Nitride and its associated alloys InGaN and AlGaN have many material properties that are highly desirable for micro-electro-mechanical systems (MEMS), and more specifically micro-opto-electro-mechanical systems (MOEMS). The group III-nitrides are tough, stiff, optically transparent, direct bandgap, chemically inert, highly piezoelectric, and capable of functioning at high temperatures. There is currently no other semiconductor system that possesses all of these properties. Taken together, these attributes make the nitrides prime candidates not only for creating new versions of existing device structures, but also for creating entirely unique devices which combine these properties in novel ways. Unfortunately, their chemical resiliency also makes the group III-nitrides extraordinarily difficult to shape into devices. In particular, until this research, no undercut etch technology existed that could controllably separate a selected part of a MEMS device from its sapphire or silicon carbide substrate. This has effectively prevented GaN-based MEMS from being developed. This dissertation describes how this fabrication obstacle was overcome by a novel etching geometry (bandgap-selective backside-illuminated photoelectochemical (BS-BIPEC) etching) and its resulting morphologies. Several gallium-nitride based MEMS devices were created, actuated, and modelled, including cantilevers and membranes. We describe in particular our pursuit of one of the many novel device elements that is possible only in this material system: a transducer that uses an externally applied strain to dynamically change the optical transition energy of a quantum well. While the device objective of a dynamically tunable quantum well was not achieved, we have demonstrated sufficient progress to believe that such a device will be possible soon. We have observed a shift (5.5meV) of quantum well transition energies in released structures, and we have created structures that can apply large biaxial

  1. Novel ethylenediamine-gallium phosphate containing 6-fold coordinated gallium atoms with unusual four equatorial Ga–N bonds

    Energy Technology Data Exchange (ETDEWEB)

    Torre-Fernández, Laura [Departamentos de Química Física y Analítica y Química Orgánica e Inorgánica, Universidad de Oviedo-CINN, 33006 Oviedo (Spain); Espina, Aránzazu; Khainakov, Sergei A.; Amghouz, Zakariae [Servicios Científico Técnicos, Universidad de Oviedo, 33006 Oviedo (Spain); García, José R. [Departamentos de Química Física y Analítica y Química Orgánica e Inorgánica, Universidad de Oviedo-CINN, 33006 Oviedo (Spain); García-Granda, Santiago, E-mail: sgg@uniovi.es [Departamentos de Química Física y Analítica y Química Orgánica e Inorgánica, Universidad de Oviedo-CINN, 33006 Oviedo (Spain)

    2014-07-01

    A novel ethylenediamine-gallium phosphate, formulated as Ga(H{sub 2}NCH{sub 2}CH{sub 2}NH{sub 2}){sub 2}PO{sub 4}·2H{sub 2}O, was synthesized under hydrothermal conditions. The crystal structure, including hydrogen positions, was determined using single-crystal X-ray diffraction data (monoclinic, a=9.4886(3) Å, b=6.0374(2) Å, c=10.2874(3) Å, and β=104.226(3)°, space group Pc) and the bulk was characterized by chemical (Ga–P–C–H–N) and thermal analysis (TG–MS and DSC), including activation energy data of its thermo-oxidative degradation, powder X-ray diffraction (PXRD), solid-state nuclear magnetic resonance (SS-NMR) measurements, and transmission electron microscopy (TEM, SAED/NBD, and STEM BF-EDX). The crystal structure is built up of infinite zig-zag chains running along the c-axis, formed by vertex-shared (PO{sub 4}) and (GaO{sub 2}N{sub 4}) polyhedra. The new compound is characterized by unusual four equatorial Ga–N bonds coming from two nonequivalent ethylenediamine molecules and exhibits strong blue emission at 430 nm (λ{sub ex}=350 nm) in the solid state at room temperature. - Graphical abstract: Single crystals of a new ethylenediamine-gallium phosphate, Ga(H{sub 2}NCH{sub 2}CH{sub 2}NH{sub 2}){sub 2}PO{sub 4}·2H{sub 2}O, were obtained and the structural features presented. This structure is one of the scarce examples of GaPO with Ga–N bonds reported. - Highlights: • A novel ethylenediamine-gallium phosphate was hydrothermally synthesized. • The new compound is characterized by unusual four equatorial Ga–N bonds. • Void-volume analysis shows cages and channels with sizes ideally suited to accommodate small molecules. • The new compound exhibits strong blue emission.

  2. On the nature of gallium species in gallium-modified mordenite and MFI zeolites. A comparative DRIFT study of carbon monoxide adsorption and hydrogen dissociation.

    Science.gov (United States)

    Serykh, Alexander I; Kolesnikov, Stanislav P

    2011-04-21

    The results of a DRIFT study of carbon monoxide molecular adsorption and hydrogen dissociative adsorption on gallium-modified mordenite and MFI (ZSM-5) zeolites are presented. It was found that in the reduced gallium-modified mordenite (Ga-MOR) both Ga(3+) and Ga(+) exchanged cations are present and can be detected by CO adsorption. Ga(3+) cations in Ga-MOR dissociatively adsorb molecular hydrogen at elevated temperatures, resulting in the formation of gallium hydride species and acidic hydroxyl groups. In the reduced Ga-MFI evacuated at 823 K under medium vacuum conditions only Ga(+) exchanged intrazeolite cations were detected. It was found, however, that Ga(3+) intrazeolite exchanged cations which form upon high-temperature disproportionation of Ga(+) cations in the reduced Ga-MFI and Ga-MOR can be stabilized by high-temperature oxidation of these zeolites.

  3. High-Temperature Decomposition of Brønsted Acid Sites in Gallium-Substituted Zeolites

    Energy Technology Data Exchange (ETDEWEB)

    K Al-majnouni; N Hould; W Lonergan; D Vlachos; R Lobo

    2011-12-31

    The dehydroxylation of Broensted acid sites (BAS) in Ga-substituted zeolites was investigated at temperatures up to 850 C using X-ray absorption spectroscopy (XAS), Fourier transform infrared spectroscopy (FTIR), and mass spectrometry-temperature programmed desorption (MS-TPD). X-ray absorption near-edge spectroscopy (XANES) revealed that the majority of gallium has tetrahedral coordination even after complete dehydroxylation. The interatomic gallium-oxygen distance and gallium coordination number determined by extended X-ray absorption fine structure (EXAFS) are consistent with gallium in tetrahedral coordination at low T (< 550 C). Upon heating Ga-Beta and Ga-ZSM5 to 850 C, analysis of the EXAFS showed that 70 and 80% of the gallium was still in tetrahedral coordination. The remainder of the gallium was found to be in octahedral coordination. No trigonal Ga atoms were observed. FTIR measurements carried out at similar temperatures show that the intensity of the OH vibration due to BAS has been eliminated. MS-TPD revealed that hydrogen in addition to water evolved from the samples during dehydroxylation. This shows that dehydrogenation in addition to dehydration is a mechanism that contributes to BAS decomposition. Dehydrogenation was further confirmed by exposing the sample to hydrogen to regenerate some of the BAS as monitored by FTIR and MS-TPD.

  4. Density Functional Theory Study on Defect Feature of AsGaGaAs in Gallium Arsenide

    Directory of Open Access Journals (Sweden)

    Deming Ma

    2015-01-01

    Full Text Available We investigate the defect feature of AsGaGaAs defect in gallium arsenide clusters in detail by using first-principles calculations based on the density functional theory (DFT. Our calculations reveal that the lowest donor level of AsGaGaAs defect on the gallium arsenide crystal surface is 0.85 eV below the conduction band minimum, while the lowest donor level of the AsGaGaAs defect inside the gallium arsenide bulk is 0.83 eV below the bottom of the conduction band, consistent with gallium arsenide EL2 defect level of experimental value (Ec-0.82 eV. This suggests that AsGaGaAs defect is one of the possible gallium arsenide EL2 deep-level defects. Moreover, our results also indicate that the formation energies of internal AsGaGaAs and surface AsGaGaAs defects are predicted to be around 2.36 eV and 5.54 eV, respectively. This implies that formation of AsGaGaAs defect within the crystal is easier than that of surface. Our results offer assistance in discussing the structure of gallium arsenide deep-level defect and its effect on the material.

  5. Epitaxially-grown Gallium Nitride on Gallium Oxide substrate for photon pair generation in visible and telecomm wavelengths

    KAUST Repository

    Awan, Kashif M.; Dolgaleva, Ksenia; Mumthaz Muhammed, Mufasila; Roqan, Iman S.

    2016-01-01

    Gallium Nitride (GaN), along with other III-Nitrides, is attractive for optoelectronic and electronic applications due to its wide direct energy bandgap, as well as high thermal stability. GaN is transparent over a wide wavelength range from infra-red to the visible band, which makes it suitable for lasers and LEDs. It is also expected to be a suitable candidate for integrated nonlinear photonic circuits for a wide range of applications from all-optical signal processing to quantum computing and on-chip wavelength conversion. Despite its abundant use in commercial devices, there is still need for suitable substrate materials to reduce high densities of threading dislocations (TDs) and other structural defects like stacking faults, and grain boundaries. All these defects degrade the optical quality of the epi-grown GaN layer as they act as non-radiative recombination centers.

  6. Epitaxially-grown Gallium Nitride on Gallium Oxide substrate for photon pair generation in visible and telecomm wavelengths

    KAUST Repository

    Awan, Kashif M.

    2016-08-11

    Gallium Nitride (GaN), along with other III-Nitrides, is attractive for optoelectronic and electronic applications due to its wide direct energy bandgap, as well as high thermal stability. GaN is transparent over a wide wavelength range from infra-red to the visible band, which makes it suitable for lasers and LEDs. It is also expected to be a suitable candidate for integrated nonlinear photonic circuits for a wide range of applications from all-optical signal processing to quantum computing and on-chip wavelength conversion. Despite its abundant use in commercial devices, there is still need for suitable substrate materials to reduce high densities of threading dislocations (TDs) and other structural defects like stacking faults, and grain boundaries. All these defects degrade the optical quality of the epi-grown GaN layer as they act as non-radiative recombination centers.

  7. Fabrication and Characterization of Vertical Gallium Nitride Power Schottky Diodes on Bulk GaN Substrates FY2016

    Science.gov (United States)

    2016-12-01

    ARL-TR-7913 ● DEC 2016 US Army Research Laboratory Fabrication and Characterization of Vertical Gallium Nitride Power Schottky...TR-7913 ● DEC 2016 US Army Research Laboratory Fabrication and Characterization of Vertical Gallium Nitride Power Schottky Diodes on Bulk...Fabrication and Characterization of Vertical Gallium Nitride Power Schottky Diodes on Bulk GaN Substrates FY2016 5a. CONTRACT NUMBER 5b. GRANT NUMBER

  8. Distribution of trace levels of therapeutic gallium in bone as mapped by synchrotron X-ray microscopy

    International Nuclear Information System (INIS)

    Bockman, R.S.; Repo, M.A.; Warrell, R.P. Jr.; Pounds, J.G.; Schidlovsky, G.; Gordon, B.M.; Jones, K.W.

    1990-01-01

    Gallium nitrate, a drug that inhibits calcium release from bone, has been proven a safe and effective treatment for the accelerated bone resorption associated with cancer. Though bone is a target organ for gallium, the kinetics, sites, and effects of gallium accumulation in bone are not known. The authors have used synchrotron X-ray microscopy to map the distribution of trace levels of gallium in bone. After short-term in vivo administration of gallium nitrate to rats, trace (nanogram) amounts of gallium preferentially localized to the metabolically active regions in the metaphysis as well as the endosteal and periosteal surfaces of diaphyseal bone, regions where new bone formation and modeling were occurring. The amounts measured were well below the levels known to be cytotoxic. Iron and zinc, trace elements normally found in bone, were decreased in amount after in vivo administration of gallium. These studies represent a first step toward understanding the mechanism(s) of action of gallium in bone by suggesting the possible cellular, structural, and elemental targets of gallium

  9. Theoretical exploration of structural, electro-optical and magnetic properties of gallium-doped silicon carbide nanotubes

    Science.gov (United States)

    Behzad, Somayeh; Chegel, Raad; Moradian, Rostam; Shahrokhi, Masoud

    2014-09-01

    The effects of gallium doping on the structural, electro-optical and magnetic properties of (8,0) silicon carbide nanotube (SiCNT) are investigated by using spin-polarized density functional theory. It is found from the calculation of the formation energies that gallium substitution for silicon atom is preferred. Our results show that gallium substitution at either single carbon or silicon atom site in SiCNT could induce spontaneous magnetization. The optical studies based on dielectric function indicate that new transition peaks and a blue shift are observed after gallium doping.

  10. Angrites: A Volatile-rich Variety of Asteroidal Basalt (Except for Alkalis and Gallium!)

    Science.gov (United States)

    Warren, P. H.; Kallemeyn, G. W.

    1995-09-01

    Angrites are commonly viewed as extremely volatile-depleted, and a related notion is that they formed by differentiation of a very CAI-rich material [e.g., 1]. Partial melting experiments reportedly reproduce the bulk compositions (although not fassaite-rich mineralogy) of angrites with Allende as starting material [2], but highly CAI-rich parent materials are difficult to reconcile with isotopic and REE data [3,4]. Mittlefehldt and Lindstrom [5] inferred from the low Na/Al ratios of angrites that outgassing, and thus primordial magmatism, was more intense on their parent body than on the eucrite parent asteroid. Of seven elements that (a) have been adequately determined in angrites, and (b) are far more volatile (solar-nebula 50% condensation T [6] = 690-430 K) than the alkalis (1000-910 K), four are enriched, and none is significantly depleted, in average angrite compared to average eucrite or low-Ti mare basalt (Figure). Gallium, which is of intermediate volatility (830 K), is depleted to roughly the same extent as Na and K. Results for A881371 [3] are incomplete (Zn, 6 micrograms/g, is near INAA detection limit), but even based only on AdoR and the two LEW angrites, this pattern seems firmly established. Apparent gas cavities in A881371 [7] also suggest that volatiles are far from uniformly depleted. The only elements known to be depleted, as volatiles, by clearly significant factors in angrites versus eucrites or lunar basalts, are alkalis plus gallium. Besides being moderately volatile, a noteworthy characteristic shared among Ga and alkalis (and not shared with elements such as Br, Se, and Zn) is that these elements probably tend to partition into crustal feldspar during gross differentiation of small (low-pressure) bodies. If gallium + alkalis were depleted by a single process starting from "normal" chondritic material, that process would seem to require selective exposure of a feldspar-enriched region (i.e., crust) to extremely high temperature. Igneous

  11. Numerical Analysis of Copper-Indium-Gallium-Diselenide-Based Solar Cells by SCAPS-1D

    Directory of Open Access Journals (Sweden)

    S. Ouédraogo

    2013-01-01

    Full Text Available We used a one-dimensional simulation program Solar Cell Capacitance Simulator in 1 Dimension (SCAPS-1D to investigate Copper-Indium-Gallium-Diselenide- (CIGS- based solar cells properties. Starting with a conventional ZnO-B/i-ZnO/CdS/CIGS structure, we simulated the parameters of current-voltage characteristics and showed how the absorber layer thickness, hole density, and band gap influence the short-circuit current density (Jsc, open-circuit voltage (Voc, fill factor (FF, and efficiency of solar cell. Our simulation results showed that all electrical parameters are greatly affected by the absorber thickness (w below 1000 nm, due to the increase of back-contact recombination and very poor absorption. Increasing hole density (p or absorber band gap (Eg improves Voc and leads to high efficiency, which equals value of 16.1% when p = 1016 cm−3 and Eg=1.2 eV. In order to reduce back-contact recombination, the effect of a very thin layer with high band gap inserted near the back contact and acting as electrons reflector, the so-called back-electron reflector (EBR, has been investigated. The performances of the solar cells are significantly improved, when ultrathin absorbers (w < 500 nm are used; the corresponding gain of Jsc due to the EBR is 3 mA/cm2. Our results are in good agreement with those reported in the literature from experiments.

  12. Gallium diffusion in zinc oxide via the paired dopant-vacancy mechanism

    Science.gov (United States)

    Sky, T. N.; Johansen, K. M.; Riise, H. N.; Svensson, B. G.; Vines, L.

    2018-02-01

    Isochronal and isothermal diffusion experiments of gallium (Ga) in zinc oxide (ZnO) have been performed in the temperature range of 900-1050 °C. The samples used consisted of a sputter-deposited and highly Ga-doped ZnO film at the surface of a single-crystal bulk material. We use a novel reaction diffusion (RD) approach to demonstrate that the diffusion behavior of Ga in ZnO is consistent with zinc vacancy (VZn) mediation via the formation and dissociation of GaZnVZn complexes. In the RD modeling, experimental diffusion data are fitted utilizing recent density-functional-theory estimates of the VZn formation energy and the binding energy of GaZnVZn. From the RD modeling, a migration energy of 2.3 eV is deduced for GaZnVZn, and a total/effective activation energy of 3.0 eV is obtained for the Ga diffusion. Furthermore, and for comparison, employing the so-called Fair model, a total/effective activation energy of 2.7 eV is obtained for the Ga diffusion, reasonably close to the total value extracted from the RD-modeling.

  13. Liquid gallium cooling of silicon crystals in high intensity photon beam

    International Nuclear Information System (INIS)

    Smither, R.K.; Forster, G.A.; Bilderback, D.H.

    1988-11-01

    The high-brilliance, insertion-device-based, photon beams of the next generation of synchrotron sources will deliver large thermal loads (1 kW to 10 kW) to the first optical elements. Considering the problems that present synchrotron users are experiencing with beams from recently installed insertion devices, new and improved methods of cooling these first optical elements, particularly when they are diffraction crystals, are clearly needed. A series of finite element calculations were performed to test the efficiency of new cooling geometries and new cooling fluids. The best results were obtained with liquid Ga metal flowing in channels just below the surface of the crystal. Ga was selected because of its good thermal conductivity and thermal capacity, low melting point, high boiling point, low kinetic viscosity, and very low vapor pressure. Its very low vapor pressure, even at elevated temperatures, makes it especially attractive in uhv conditions. A series of experiments were conducted at CHESS in February of 1988 that compared liquid gallium cooled silicon diffraction crystals with water cooled crystals. 2 refs., 16 figs., 1 tab

  14. Platinum nanoparticles on gallium nitride surfaces: effect of semiconductor doping on nanoparticle reactivity.

    Science.gov (United States)

    Schäfer, Susanne; Wyrzgol, Sonja A; Caterino, Roberta; Jentys, Andreas; Schoell, Sebastian J; Hävecker, Michael; Knop-Gericke, Axel; Lercher, Johannes A; Sharp, Ian D; Stutzmann, Martin

    2012-08-01

    Platinum nanoparticles supported on n- and p-type gallium nitride (GaN) are investigated as novel hybrid systems for the electronic control of catalytic activity via electronic interactions with the semiconductor support. In situ oxidation and reduction were studied with high pressure photoemission spectroscopy. The experiments revealed that the underlying wide-band-gap semiconductor has a large influence on the chemical composition and oxygen affinity of supported nanoparticles under X-ray irradiation. For as-deposited Pt cuboctahedra supported on n-type GaN, a higher fraction of oxidized surface atoms was observed compared to cuboctahedral particles supported on p-type GaN. Under an oxygen atmosphere, immediate oxidation was recorded for nanoparticles on n-type GaN, whereas little oxidation was observed for nanoparticles on p-type GaN. Together, these results indicate that changes in the Pt chemical state under X-ray irradiation depend on the type of GaN doping. The strong interaction between the nanoparticles and the support is consistent with charge transfer of X-ray photogenerated free carriers at the semiconductor-nanoparticle interface and suggests that GaN is a promising wide-band-gap support material for photocatalysis and electronic control of catalysis.

  15. Gallium and silicon synergistically promote osseointegration of dental implant in patients with osteoporosis.

    Science.gov (United States)

    Liu, Jinsong; Wu, Zuosu; He, Hongli; Cai, Kaiyong; Zhang, Hualin; Xu, Lihua

    2017-06-01

    Over the last few decades, a wide variety of dental implants have been successfully placed in jaw bones to restore tooth function. But major challenges still remain in patients with osteoporosis involving compromised osseointegration, and the therapeutic methods is far from optimism. Gallium can directly inhibit bone osteolysis, prevent bone calcium release and augment bone mass, which makes Ga unique among the potential antiresorptive drugs. Silicon, as an indispensable modulator in bone formation, presents its bone anabolic effects, while reduces, at least doesn't increase, bone resorption. We hypothesize that the combination of bone anabolic effects of Si and antiresorptive effects of Ga will result in synergistic effects on the improvement of osteointegration under osteoporotic condition. In our strategy, in order to maximize the efficacy while minimize the side effects of ions, a novel titania mesoporous layer fabricated by electrochemical anodization on the surface of titanium implant will be employed as a promising local drug delivery system. The synergistic effects of Ga and Si on improving osseointegration will be verified by animal experiments, and be furthered by clinical trials. Our hypothesis could help to create an option to improve success rate of dental implants in osteoporotic patients. Copyright © 2017. Published by Elsevier Ltd.

  16. Electronic structure, Born effective charges and spontaneous polarization in magnetoelectric gallium ferrite

    International Nuclear Information System (INIS)

    Roy, Amritendu; Garg, Ashish; Mukherjee, Somdutta; Gupta, Rajeev; Prasad, Rajendra; Auluck, Sushil

    2011-01-01

    We present a theoretical study of the structure-property correlation in gallium ferrite, based on first-principles calculations followed by a subsequent comparison with experiments. The local spin density approximation (LSDA + U) of the density functional theory has been used to calculate the ground state structure, electronic band structure, density of states and Born effective charges. The calculations reveal that the ground state structure is orthorhombic Pc 2 1 n having A-type antiferromagnetic spin configuration, with lattice parameters matching well with those obtained experimentally. Plots of the partial density of states of constituent ions exhibit noticeable hybridization of Fe 3d, Ga 4s, Ga 4p and O 2p states. However, the calculated charge density and electron localization function show a largely ionic character of the Ga/Fe-O bonds which is also supported by a lack of any significant anomaly in the calculated Born effective charges with respect to the corresponding nominal ionic charges. The calculations show a spontaneous polarization of ∼ 59 μC cm -2 along the b-axis which is largely due to asymmetrically placed Ga1, Fe1, O1, O2 and O6 ions.

  17. Growth and etching characteristics of gallium oxide thin films by pulsed laser deposition

    International Nuclear Information System (INIS)

    Ou, Sin-Liang; Wuu, Dong-Sing; Fu, Yu-Chuan; Liu, Shu-Ping; Horng, Ray-Hua; Liu, Lei; Feng, Zhe-Chuan

    2012-01-01

    Highlights: ► The β-Ga2O3 thin films are prepared by pulsed laser deposition. ► The substrate temperature affects the structural, optical and etching properties of the grown films. ► The optical transmittance and band gap of the films increased with increasing the substrate temperature. ► The etching treatments for gallium oxide are performed in 49 mol% HF solution at room temperature. ► The gallium oxide thin film grown at 400 °C has the highest etching rate of 490 nm s −1 . - Abstract: The gallium oxide films were deposited on (0 0 1) sapphire at various substrate temperatures from 400 to 1000 °C by pulsed laser deposition using a KrF excimer laser. The etching treatments for as-grown gallium oxide were performed in a 49 mol% HF solution at room temperature. The structural, optical and etching properties of the grown films were investigated in terms of high resolution X-ray diffraction, optical transmittance, atomic force microscopy, and X-ray photoelectron spectroscopy. The phase transition from amorphous to polycrystalline β-Ga 2 O 3 structure was observed with increasing growth temperature. From the optical transmittance measurements, the films grown at 550–1000 °C exhibit a clear absorption edge at deep ultraviolet region around 250–275 nm wavelength. It was found that the optical band gap of gallium oxide films increased from 4.56 to 4.87 eV when the substrate temperature increased from 400 to 1000 °C. As the substrate temperature increases, the crystallinity of gallium oxide film is enhanced and the etching rate is decreased. The high etching rate of 490 nm s −1 for gallium oxide film grown at 400 °C could be due to its amorphous phase, which is referred to higher void ratio and looser atomic structure.

  18. Pulmonary gallium uptake in rats with granulomatosis induced by complete Freund adjuvant

    International Nuclear Information System (INIS)

    Stanislas-Leguern, G.; Masse, R.; Jaubert, F.; Chretien, J.; Huchon, G.

    1988-01-01

    To investigate the mechanism of gallium-67 uptake in lung granulomatosis, we studied 13 rats in which lung granulomatosis was induced by injection of complete Freund adjuvant (CFA) and 14 controls. Gallium uptake was assessed in bronchoalveolar lavage fluid and lavaged lung. The cells responsible for gallium uptake were identified by latent image activation autoradiography. Gallium activity in both lavaged lungs and bronchoalveolar cells (BAC) was higher in CFA-treated animals than in controls [172,205 +/- 134,783 DPM versus 44,456 +/- 14,486 DPM +/- SD (p less than 0.05) and 40,083 +/- 16,350 DPM versus 9100 +/- 4114 DPM (p less than 0.05), respectively]. In control rats, about two-thirds of total lung gallium was located in the interstitium, whereas in CFA-treated rats it was found in the mononuclear cells of lung granulomas. Gallium tracks were more numerous in the alveolar macrophages (AM) of CFA-treated rats than in control AM (28.4 +/- 10.0/field versus 8.4 +/- 3.8/field, p less than 0.001) but the number of tracks was proportional to the number of AM (52.4 +/- 18.7 versus 12.2 +/- 4.3, respectively; p less than 0.001). It is concluded that in rats with CFA-induced lung granulomatosis 1) pulmonary gallium uptake increases, 2) mononuclear cells are responsible for this uptake in both granulomas and AM, and 3) the increased uptake is due to the increased number of mononuclear cells

  19. Gallium Phosphide Integrated with Silicon Heterojunction Solar Cells

    Science.gov (United States)

    Zhang, Chaomin

    It has been a long-standing goal to epitaxially integrate III-V alloys with Si substrates which can enable low-cost microelectronic and optoelectronic systems. Among the III-V alloys, gallium phosphide (GaP) is a strong candidate, especially for solar cells applications. Gallium phosphide with small lattice mismatch ( 0.4%) to Si enables coherent/pseudomorphic epitaxial growth with little crystalline defect creation. The band offset between Si and GaP suggests that GaP can function as an electron-selective contact, and it has been theoretically shown that GaP/Si integrated solar cells have the potential to overcome the limitations of common a-Si based heterojunction (SHJ) solar cells. Despite the promising potential of GaP/Si heterojunction solar cells, there are two main obstacles to realize high performance photovoltaic devices from this structure. First, the growth of the polar material (GaP) on the non-polar material (Si) is a challenge in how to suppress the formation of structural defects, such as anti-phase domains (APD). Further, it is widely observed that the minority-carrier lifetime of the Si substrates is significantly decreased during epitaxially growth of GaP on Si. In this dissertation, two different GaP growth methods were compared and analyzed, including migration-enhanced epitaxy (MEE) and traditional molecular beam epitaxy (MBE). High quality GaP can be realized on precisely oriented (001) Si substrates by MBE growth, and the investigation of structural defect creation in the GaP/Si epitaxial structures was conducted using high resolution X-ray diffraction (HRXRD) and high resolution transmission electron microscopy (HRTEM). The mechanisms responsible for lifetime degradation were further investigated, and it was found that external fast diffusors are the origin for the degradation. Two practical approaches including the use of both a SiNx diffusion barrier layer and P-diffused layers, to suppress the Si minority-carrier lifetime degradation

  20. Solar neutrino results from SAGE

    International Nuclear Information System (INIS)

    Gavrin, V.N.

    1999-01-01

    We report the status of the Russian-American Gallium solar neutrino Experiment (SAGE). The solar neutrino result for SAGE III, 20 runs during the measuring period May 1995 through December 1997, is 56.7 +9.3/-8.7(stat.)+4.6/-4.8(syst.) SNU. The combined result for 57 measurements from 1990 through 1997 (SAGE I+II+III) is 66.9 +7.1/-6.8 (stat) +5.4/-5.7 (syst) SNU. The final result of the SAGE 51 Cr experiment to check the response of SAGE to low energy neutrinos is also presented

  1. Bone marrow accumulation in gallium scintigraphy in patients with adult still's disease

    Energy Technology Data Exchange (ETDEWEB)

    Kanegae, Futoshi; Tada, Yoshifumi; Ohta, Akihide; Ushiyama, Osamu; Suzuki; Noriaki; Koarada, Syuichi; Haruta, Yoshio; Yoshikai, Tomonori; Nagasawa, Kohei [Saga Medical School (Japan)

    2002-12-01

    We investigated the features and the usefulness of gallium scintigraphy in the diagnosis and the assessment of Adult Still's disease (ASD) by retrospective case review. Gallium scintigraphy have been done for 11 cases of ASD (3 males and 8 females) and 4 females were positive. Among these, 67 Ga-citrate was accumulated to the bone marrow in all 4 cases and to the major joints in 2 cases. Positive cases were rather serious and administered more immunosuppressants than negative cases. In order to characterize gallium scintigraphy findings of ASD, i.e. bone marrow accumulation, we analyzed 130 cases of collagen vascular disease. Although 101 cases (77.7%) were positive, only 7 cases (5.4%) showed the accumulation of {sup 67}Ga-citrate to the bone marrow. These include 3 cases with ASD, and 1 case with systemic lupus erythematosus, polyarteritis nodosa, Wegener's granulomatosis and Sjogren's syndrome. We also accumulated 18 patients who exhibited bone marrow accumulation of {sup 69}Ga-citrate, and found that 7 patients had collagen vascular and their related diseases. In conclusion, bone marrow accumulation in gallium scintigraphy is a specific feature of collagen vascular diseases, especially ASD, and it is suggested that cases with positive gallium scintigraphy in ASD can be serious and resistant to treatment. (author)

  2. Cleansing the colon in gallium-67 scintigraphy: a prospective comparison of regimens

    International Nuclear Information System (INIS)

    Novetsky, G.J.; Turner, D.A.; Ali, A.; Raynor, W.J.; Fordham, E.W.

    1981-01-01

    Colonic accumulation of gallium-67 frequently complicates the interpretation of gallium-67 scintigrams. Although various modes of cleansing the colon prior to scintigraphy have been suggested, there is controversy over their efficacy and none have been tested prospectively. Three hundred nine patients undergoing gallium-67 scintigraphy were randomly assigned to one of four cleansing regimens: (1) a high fiber diet (78 patients); (2) castor oil (76); (3) milk of magnesia and cascara (76); and (4) no preparation (79). Patient compliance rates for the four regimens were 17%, 32%, 36%, and 46%, respectively. After noncompliant patients were excluded, gallium-67 scintigrams were graded for colonic activity on a scale of 0-3 by three independent, experienced observers. Gallium-67 activity in the colon was significantly less after adminstration of castor oil than after no prepartion (p = 0.083). Regimen 3 did not produce significantly better results than regimen 4 (p = 0.42). A major impediment to the success of any cleansing regimen seems to be poor compliance of patients

  3. Investigating change of properties in gallium ion irradiation patterned single-layer graphene

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Quan, E-mail: wangq@mail.ujs.edu.cn [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences (China); Dong, Jinyao; Bai, Bing [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); Xie, Guoxin [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China)

    2016-10-14

    Besides its excellent physical properties, graphene promises to play a significant role in electronics with superior properties, which requires patterning of graphene for device integration. Here, we presented the changes in properties of single-layer graphene before and after patterning using gallium ion beam. Combined with Raman spectra of graphene, the scanning capacitance microscopy (SCM) image confirmed that a metal–insulator transition occurred after large doses of gallium ion irradiation. The changes in work function and Raman spectra of graphene indicated that the defect density increased as increasing the dose and a structural transition occurred during gallium ion irradiation. The patterning width of graphene presented an increasing trend due to the scattering influence of the impurities and the substrate. - Highlights: • The scanning capacitance microscopy image confirmed a metal–insulator transition occurred after large doses of gallium ion irradiation. • The changes indicated the defect density increased as increasing the dose and a structural transition occurred during gallium ion irradiation. • The patterning width of graphene presented a increasing trend due to the scattering influence of the impurities and the substrate.

  4. Preparation of gallium-68 radiopharmaceuticals for positron tomography. Progress report, November 1, 1980-December 31, 1981

    International Nuclear Information System (INIS)

    Welch, M.J.

    1981-06-01

    Although the germanium-68 → gallium-68 generator is probably the only source of positron-emitting radionuclides that could enable the widespread application of positron tomography, the commercially available 68 Ga/ 68 Ge generator system suffers from several major disadvantages. The most important of these is that the generator is eluted with EDTA, which forms a very strong chelate with gallium. In order to produce radiopharmaceuticals other than 68 Ga-EDTA, it is first necessary to break the stable EDTA complex and remove all traces of EDTA. This procedure adds several steps and a significant amount of time to procedures for preparing 68 Ga-radiopharmaceuticals. Several years ago, we developed a new generator using a solvent extraction system which produces 68 Ga-oxine (8-hydroxyquinoline), a weak chelate. We have also carried out studies to compare generator systems which produce 68 Ga in an ionic form. Using the gallium-68 eluted from these various generator systems, several 68 Ga-labeled radiopharmaceuticals have been synthesized and tested in vitro and in vivo. In addition, attempts have been made to design and synthesize a lipophilic ligand for gallium-68. The stability of radiogallium complexed with a series of potentially lipophilic complexing agents has been studied using chromatographic techniques and in vivo distribution data. The potential of these complexing agents for altering the biodistribution of gallium radiopharmaceuticals has also been investigated

  5. Bone marrow accumulation in gallium scintigraphy in patients with adult still's disease

    International Nuclear Information System (INIS)

    Kanegae, Futoshi; Tada, Yoshifumi; Ohta, Akihide; Ushiyama, Osamu; Suzuki; Noriaki; Koarada, Syuichi; Haruta, Yoshio; Yoshikai, Tomonori; Nagasawa, Kohei

    2002-01-01

    We investigated the features and the usefulness of gallium scintigraphy in the diagnosis and the assessment of Adult Still's disease (ASD) by retrospective case review. Gallium scintigraphy have been done for 11 cases of ASD (3 males and 8 females) and 4 females were positive. Among these, 67 Ga-citrate was accumulated to the bone marrow in all 4 cases and to the major joints in 2 cases. Positive cases were rather serious and administered more immunosuppressants than negative cases. In order to characterize gallium scintigraphy findings of ASD, i.e. bone marrow accumulation, we analyzed 130 cases of collagen vascular disease. Although 101 cases (77.7%) were positive, only 7 cases (5.4%) showed the accumulation of 67 Ga-citrate to the bone marrow. These include 3 cases with ASD, and 1 case with systemic lupus erythematosus, polyarteritis nodosa, Wegener's granulomatosis and Sjogren's syndrome. We also accumulated 18 patients who exhibited bone marrow accumulation of 69 Ga-citrate, and found that 7 patients had collagen vascular and their related diseases. In conclusion, bone marrow accumulation in gallium scintigraphy is a specific feature of collagen vascular diseases, especially ASD, and it is suggested that cases with positive gallium scintigraphy in ASD can be serious and resistant to treatment. (author)

  6. The global anthropogenic gallium system: determinants of demand, supply and efficiency improvements.

    Science.gov (United States)

    Løvik, Amund N; Restrepo, Eliette; Müller, Daniel B

    2015-05-05

    Gallium has been labeled as a critical metal due to rapidly growing consumption, importance for low-carbon technologies such as solid state lighting and photovoltaics, and being produced only as a byproduct of other metals (mainly aluminum). The global system of primary production, manufacturing, use and recycling has not yet been described or quantified in the literature. This prevents predictions of future demand, supply and possibilities for efficiency improvements on a system level. We present a description of the global anthropogenic gallium system and quantify the system using a combination of statistical data and technical parameters. We estimated that gallium was produced from 8 to 21% of alumina plants in 2011. The most important applications of gallium are NdFeB permanent magnets, integrated circuits and GaAs/GaP-based light-emitting diodes, demanding 22-37%, 16-27%, and 11-21% of primary metal production, respectively. GaN-based light-emitting diodes and photovoltaics are less important, both with 2-6%. We estimated that 120-170 tons, corresponding to 40-60% of primary production, ended up in production wastes that were either disposed of or stored. While demand for gallium is expected to rise in the future, our results indicated that it is possible to increase primary production substantially with conventional technology, as well as improve the system-wide material efficiency.

  7. Cleansing the colon in gallium-67 scintigraphy: a prospective comparison of regimens.

    Science.gov (United States)

    Novetsky, G J; Turner, D A; Ali, A; Raynor, W J; Fordham, E W

    1981-11-01

    Colonic accumulation of gallium-67 frequently complicates the interpretation of gallium-67 scintigrams. Although various modes of cleansing the colon prior to scintigraphy have been suggested, there is controversy over their efficacy and none have been tested prospectively. Three hundred nine patients undergoing gallium-67 scintigraphy were randomly assigned to one of four cleansing regimens: (1) a high fiber diet (78 patients); (2) castor oil (76); (3) milk of magnesia and cascara (76); and (4) not preparation (79). Patient compliance rates for the four regimens were 17%, 32%, 36%, and 46%, respectively. After noncompliant patients were excluded, gallium-67 scintigrams were graded for colonic activity on a scale of 0-3 by three independent, experienced observers. Gallium-67 activity in the colon was significantly less after administration of castor oil than after no preparation (p = 0.047). A high fiber diet also resulted in a substantial reduction of colonic activity when compared with no preparation; the difference, however, was not statistically significant (p = 0.083). Regimen 3 did not produce significantly better results than regimen 4 (p = 0.42). A major impediment to the success of any cleansing regimen seems to be poor compliance of patients.

  8. Cleansing the colon in gallium-67 scintigraphy: a prospective comparison of regimens

    International Nuclear Information System (INIS)

    Novetsky, G.J.; Turner, D.A.; Ali, A.; Raynor, W.J. Jr.; Fordham, E.W.

    1981-01-01

    Colonic accumulation of gallium-67 frequently complicates the interpretation of gallium-67 scintigrams. Although various modes of cleansing the colon prior to scintigraphy have been suggested, there is controversy over their efficacy and none have been tested prospectively. Three hundred nine patients undergoing gallium-67 scintigraphy were randomly assigned to one of four cleansing regimens: (1) a high fiber diet (78 patients); (2) castor oil (76); (3) milk of magnesia and cascara (76); and (4) not preparation (79). Patient compliance rates for the four regimens were 17%, 32%, 36%, and 46%, respectively. After noncompliant patients were excluded, gallium-67 scintigrams were graded for colonic activity on a scale of 0-3 by three independent, experienced observers. Gallium-67 activity in the colon was significantly less after administration of castor oil than after no preparation (p . 0.047). A high fiber diet also resulted in a substantial reduction of colonic activity when compared with no preparation; the difference, however, was not statistically significant (p . 0.083). Regimen 3 did not produce significantly better results than regimen 4 (p . 0.42). A major impediment to the success of any cleansing regimen seems to be poor compliance of patients

  9. Optical properties and plasmonic response of silver-gallium nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Lereu, A. L. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6123 (United States); Aix-Marseille Université, CNRS, Centrale Marseille, Institut Fresnel, UMR 7249, 13013 Marseille (France); Lemarchand, F.; Zerrad, M. [Aix-Marseille Université, CNRS, Centrale Marseille, Institut Fresnel, UMR 7249, 13013 Marseille (France); Yazdanpanah, M. [NaugaNeedles LLC, Louisville, Kentucky 40299 (United States); Passian, A., E-mail: passianan@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6123 (United States); Department of Physics, University of Tennessee, Knoxville, Tennessee 37996 (United States); Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996-2200 (United States)

    2015-02-14

    Silver and gallium form an alloy Ag{sub 2}Ga via a room temperature spontaneous self-assembly that exhibits remarkable mechanical and electrical properties suitable for nanoscale measurements. However, whether photon excitation of plasmons in this emerging nanomaterial is retained or not has not been established. Here, we present a thin film formation of Ag{sub 2}Ga via a spreading-reactive process of liquid Ga on an Ag film and a characterization of its dielectric function ϵ(E) = ϵ{sub 1}(E) + iϵ{sub 2}(E) in the photon energy range 1.42 eV ≤ E < 4.2 eV. It is observed that while the plasmon damping increases, near an energy of 2.25 eV, the real part of ϵ exhibits a crossing with respect to that of Ag. Furthermore, the impact of new plasmon supporting materials is discussed and in order to enable further applications in plasmonics, the possibility of photon excitation of surface plasmons in Ag{sub 2}Ga is studied.

  10. Mechanochemical activation and gallium and indiaarsenides surface catalycity

    Science.gov (United States)

    Kirovskaya, I. A.; Mironova, E. V.; Umansky, I. V.; Brueva, O. Yu; Murashova, A. O.; Yureva, A. V.

    2018-01-01

    The present work has been carried out in terms of determining the possibilities for a clearer identification of the active sites nature, intermediate surface compounds nature, functional groups during adsorption and catalysis, activation of the diamond-like semiconductors surface (in particular, the AIIIBV type) based on mechanochemical studies of the “reaction medium (H2O, iso-C3H7OH) - dispersible semiconductor (GaAs, InAs)” systems. As a result, according to the read kinetic curves of dispersion in water, both acidification and alkalinization of the medium have been established and explained; increased activity of the newly formed surface has been noted; intermediate surface compounds, functional groups appearing on the real surface and under H2O adsorption conditions, adsorption and catalytic decomposition of iso-C3H7OH have been found (with explanation of the origin). The unconcealed role of coordinatively unsaturated atoms as active sites of these processes has been shown; the relative catalytic activity of the semiconductors studied has been evaluated. Practical recommendations on the preferred use of gallium arsenide in semiconductor gas analysis and semiconductor catalysis have been given in literature searches, great care should be taken in constructing both.

  11. Gallium-67 citrate imaging for the assessment of radiation pneumonitis

    International Nuclear Information System (INIS)

    Kataoka, Masaaki

    1989-01-01

    In order to evaluate its usefulness in the assessment of radiation pneumotinis, gallium-67 citrate ( 67 Ga) imaging was performed before and after radiation therapy (RT) on 103 patients with lung cancer. In 23 patients with radiation pneumonitis detected radiographically, abnormal 67 Ga uptake in sites other than tumors was found in all post-RT 67 Ga lung images. Three patterns of uptake were found: (A) focal uptake corresponding to the RT field (n=10); (B) diffuse uptake including the RT field (n=4); and (C) diffuse uptake outside the RT field (n=9). The area of 67 Ga uptake was consistent with that of interstitial pneumonitis as revealed histopathologically in 7 cases. 67 Ga uptake in pattern (C) was an indicator of poor prognosis for the patients with radiation pneumonitis. 67 Ga uptake in the patients with reversible pneumonitis disappeared with steroid therapy. Sixteen (20%) of 80 asymptomatic patients, in whose chest radiographs there was no finding of radiation pneumonitis, showed transient 67 Ga uptake. These were considered to occur in the subclinical radiation pneumonitis. These data suggest that 67 Ga imaging is more sensitive than chest radiography in the detection of radiation pneumonitis and is useful in the assessment of the extent and clinical course of radiation pneumonitis. (author)

  12. Using Gallium as a tracer for aluminium toxicity in plants

    International Nuclear Information System (INIS)

    Ragapathi, S.S.; Ritchie, R.J.

    2000-01-01

    Full text: Aluminium (Al) is the most common metal in the earth's crust and is highly toxic to the roots or plants when present in the solution as monomeric cations (e.g.: Al 3+ and AlOH 2+ ) in acid soils. Despite this long known effect there is little consensus on the physiological basis of Al toxicity, which may manifest either externally or within the symplasm. One of the major factors that has retarded progress in understanding Al toxicity in plants is the lack of a convenient radioisotope for Al. We have studied the problem of AI toxicity in yeast (Saccharomyces cerevisiae), because yeast and higher plants share similar membrane transport mechanisms. We have shown that Al and Gallium (Ga) (chemically similar element to Al) has similar toxic effect on the yeast cells and that Ga 3+ and Al 3+ exhibit competitive inhibition. We have estimated the concentration of Al and Ga inside the yeast cells. We have tested the feasibility of using 67 Ga radioisotope as a tracer for Al transport with the view of using it to investigate the mechanism of Al uptake and toxicity in plants

  13. Performance analysis and simulation of vertical gallium nitride nanowire transistors

    Science.gov (United States)

    Witzigmann, Bernd; Yu, Feng; Frank, Kristian; Strempel, Klaas; Fatahilah, Muhammad Fahlesa; Schumacher, Hans Werner; Wasisto, Hutomo Suryo; Römer, Friedhard; Waag, Andreas

    2018-06-01

    Gallium nitride (GaN) nanowire transistors are analyzed using hydrodynamic simulation. Both p-body and n-body devices are compared in terms of threshold voltage, saturation behavior and transconductance. The calculations are calibrated using experimental data. The threshold voltage can be tuned from enhancement to depletion mode with wire doping. Surface states cause a shift of threshold voltage and saturation current. The saturation current depends on the gate design, with a composite gate acting as field plate in the p-body device. He joined Bell Laboratories, Murray Hill, NJ, as a Technical Staff Member. In October 2001, he joined the Optical Access and Transport Division, Agere Systems, Alhambra, CA. In 2004, he was appointed an Assistant Professor at ETH Zurich,. Since 2008, at the University of Kassel, Kassel, Germany, and he has been a Professor the Head of the Computational Electronics and Photonics Group, and co-director of CINSaT since 2010. His research interests include computational optoelectronics, process and device design of semiconductor photonic devices, microwave components, and electromagnetics modeling for nanophotonics. Dr. Witzigmann is a senior member of the SPIE and IEEE.

  14. Gallium 67 imaging in monitoring lymphoma response to treatment

    International Nuclear Information System (INIS)

    Israel, O.; Front, D.; Lam, M.; Ben-Haim, S.; Kleinhaus, U.; Ben-Shachar, M.; Robinson, E.; Kolodny, G.M.

    1988-01-01

    The value of gallium 67 (Ga) imaging in monitoring lymphoma response to treatment was assessed in 25 patients with Ga-avid tumors and compared to body computed tomography (CT), chest radiographs, and palpation of tumor infiltrated peripheral lymph nodes. Ga imaging was negative in 95% (20/21) of the patients who were clinically considered to be in remission and in whom treatment was stopped. The disease did not recur during a follow-up of 12 to 26 months in 15 patients. Six patients developed recurrence of the disease 3 to 12 months after treatment was stopped. In all six patients Ga imaging became positive again at the time of the appearance of active disease. In the group of patients in remission, CT was negative in 57% (11/19), chest x-rays in 55% (6/11) and peripheral lymph nodes were palpated in none of the patients (13/13). In four patients that did not achieve remission after treatment, Ga scans were positive. Ga imaging appears useful in monitoring lymphoma response to treatment. This is probably because Ga imaging monitors tumor cell viability, whereas body CT and chest radiographs show the tumor mass, which may consist of fibrotic or necrotic tissue

  15. The hyperfine properties of iron-gallium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Elzain, M., E-mail: elzain@squ.edu.om; Gismelseed, A.; Al-Rawas, A.; Yousif, A.; Widatallah, H.; Al-Azri, Maya [Sultan Qaboos University, Department of Physics (Oman); Al-Barwani, M. [NYU Abu Dhabi (United Arab Emirates)

    2016-12-15

    The hyperfine properties at Fe site in iron-gallium alloy are calculated using the full-potential linear-augmented-plane-waves method. We have calculated the Fermi contact field (B{sub hf}) and isomer shift (δ) at the Fe site versus the number of neighbouring Ga atoms. We found that B{sub hf} decrease whereas δ increases with increasing number of neighbouring G atom. In addition we have calculated the hyperfine properties of FeGa system with DO{sub 3} structure, where various distributions of 4 the Ga atoms in the conventional unit cell are considered (including the regular DO{sub 3} structure). We found that the DO{sub 3} structure has the lowest energy as compared to the other configurations. The two distinct A and D sites of the ordered DO{sub 3} conventional unit cell have two distinct values for B{sub hf} and δ. On changing the atomic arrangement of the Ga atoms within the conventional unit cell, the configuration of the A site is maintained whereas that of the D site becomes imperfect. The contact magnetic hyperfine fields of the D-like sites in the imperfect structures are lower than that of the DO{sub 3}D site.

  16. Characterization of gallium-containing zeolites for catalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Sanchez, M.

    2003-12-08

    The present study considers the synthesis, characterization, and catalytic evaluation of extra-framework gallium-containing zeolites. We focus on modification of zeolites by chemical vapor deposition of trimethylgallium on HZSM-5 and Mordenite zeolites. Chapter 2 is dedicated to the chemisorption and stability of TMG on HZSM-5 and HMOR zeolites. The effect of silylation is also addressed. Some theoretical calculations are also shown in this study to support part of the experimental results. In Chapter 3, the effect of oxidation and reduction treatments on these catalysts is investigated by FTIR, ICP and multinuclei NMR. In Chapter 4, the oxidation state and Ga coordination obtained during and after thermal treatment with H2 and O2 is analysed by X-ray adsorption spectroscopy (XANES and EXAFS) and IR analysis of CO adsorption. These results allow a better understanding of the catalytic behaviour of Ga-containing zeolites catalyst. Chapter 5 consists of two parts: one discusses the H2 activation over Ga/HZSM5 and Ga/MOR catalysts by H2/D2 isotopic exchange reaction, and the second part deals with the aromatization of n-heptane over the same catalysts.

  17. Optical Properties of Strained Wurtzite Gallium Phosphide Nanowires

    KAUST Repository

    Greil, J.

    2016-06-08

    Wurtzite gallium phosphide (WZ GaP) has been predicted to exhibit a direct bandgap in the green spectral range. Optical transitions, however, are only weakly allowed by the symmetry of the bands. While efficient luminescence has been experimentally shown, the nature of the transitions is not yet clear. Here we apply tensile strain up to 6% and investigate the evolution of the photoluminescence (PL) spectrum of WZ GaP nanowires (NWs). The pressure and polarization dependence of the emission together with a theoretical analysis of strain effects is employed to establish the nature and symmetry of the transitions. We identify the emission lines to be related to localized states with significant admixture of Γ7c symmetry and not exclusively related to the Γ8c conduction band minimum (CBM). The results emphasize the importance of strongly bound state-related emission in the pseudodirect semiconductor WZ GaP and contribute significantly to the understanding of the optoelectronic properties of this novel material.

  18. Low-temperature thermal conductivity of terbium-gallium garnet

    International Nuclear Information System (INIS)

    Inyushkin, A. V.; Taldenkov, A. N.

    2010-01-01

    Thermal conductivity of paramagnetic Tb 3 Ga 5 O 12 (TbGG) terbium-gallium garnet single crystals is investigated at temperatures from 0.4 to 300 K in magnetic fields up to 3.25 T. A minimum is observed in the temperature dependence κ(T) of thermal conductivity at T min = 0.52 K. This and other singularities on the κ(T) dependence are associated with scattering of phonons from terbium ions. The thermal conductivity at T = 5.1 K strongly depends on the magnetic field direction relative to the crystallographic axes of the crystal. Experimental data are considered using the Debye theory of thermal conductivity taking into account resonance scattering of phonons from Tb 3+ ions. Analysis of the temperature and field dependences of the thermal conductivity indicates the existence of a strong spin-phonon interaction in TbGG. The low-temperature behavior of the thermal conductivity (field and angular dependences) is mainly determined by resonance scattering of phonons at the first quasi-doublet of the electron spectrum of Tb 3+ ion.

  19. Gallium tomoscintigraphic imaging of esophageal cancer using emission computed tomography

    International Nuclear Information System (INIS)

    Hattori, Takao; Nakagawa, Tsuyoshi; Takeda, Kan; Maeda, Hisato; Taguchi, Mitsuo

    1983-01-01

    Emission computed tomography (ECT) was clinically evaluated in 67 Ga imaging of esophageal cancer. ECT system used in this study is equipped with opposed dual large-field-of-view cameras (GCA 70A-S, Toshiba Co.). Data were acquired by rotating the two cameras 180 0 about the longitudinal axis of the patient. Total acquisition time was about 12 minutes. Multiple slices of transaxial, sagittal and coronal sections were reconstructed in a 64 x 64 matrix form using convolution algorithms. In three out of six cases studied the tumor uptake was not detected on conventional images, because the lesion was small, concentration of activity was poor or the lesion activity was overlapped with the neighbouring activities distributed to normal organs such as sternum, vertebra, liver and hilus. On ECT images, by contrast, abnormal uptake of the tumors was definitively detected in all the six cases. ECT imaging was also useful in estimating the effect of treatment by the decrease in 67 Ga concentration. We have devised a special technique to repeat ECT scan with a thin tube filled with 67 Ga solution inserted through the esophagus. By this technique, comparing paired images with and without the tube activity, exact location of the uptake against the esophagus and extraesophageal extension of the disease could be accurately evaluated in a three-dimensional field of view. ECT in gallium scanning is expected to be of great clinical value to elevate the confidence level of diagnosis in detecting, localizing and following up the diseases. (author)

  20. Piezoelectric effect on the thermal conductivity of monolayer gallium nitride

    Science.gov (United States)

    Zhang, Jin

    2018-01-01

    Using molecular dynamics and density functional theory simulations, in this work, we find that the heat transport property of the monolayer gallium nitride (GaN) can be efficiently tailored by external electric field due to its unique piezoelectric characteristic. As the monolayer GaN possesses different piezoelectric properties in armchair and zigzag directions, different effects of the external electric field on thermal conductivity are observed when it is applied in the armchair and zigzag directions. Our further study reveals that due to the elastoelectric effect in the monolayer GaN, the external electric field changes the Young's modulus and therefore changes the phonon group velocity. Also, due to the inverse piezoelectric effect, the applied electric field induces in-plane stress in the monolayer GaN subject to a length constraint, which results in the change in the lattice anharmonicity and therefore affects the phonon mean free path. Furthermore, for relatively long GaN monolayers, the in-plane stress may trigger the buckling instability, which can significantly reduce the phonon mean free path.

  1. Proton irradiation effects on gallium nitride-based devices

    Science.gov (United States)

    Karmarkar, Aditya P.

    Proton radiation effects on state-of-the-art gallium nitride-based devices were studied using Schottky diodes and high electron-mobility transistors. The device degradation was studied over a wide range of proton fluences. This study allowed for a correlation between proton irradiation effects between different types of devices and enhanced the understanding of the mechanisms responsible for radiation damage in GaN-based devices. Proton irradiation causes reduced carrier concentration and increased series resistance and ideality factor in Schottky diodes. 1.0-MeV protons cause greater degradation than 1.8-MeV protons because of their higher non-ionizing energy loss. The displacement damage in Schottky diodes recovers during annealing. High electron-mobility transistors exhibit extremely high radiation tolerance, continuing to perform up to a fluence of ˜1014 cm-2 of 1.8-MeV protons. Proton irradiation creates defect complexes in the thin-film structure. Decreased sheet carrier mobility due to increased carrier scattering and decreased sheet carrier density due to carrier removal by the defect centers are the primary damage mechanisms. Interface disorder at either the Schottky or the Ohmic contact plays a relatively unimportant part in overall device degradation in both Schottky diodes and high electron-mobility transistors.

  2. Optical and Electrical Characterization of Melt-Grown Bulk Indium Gallium Arsenide and Indium Arsenic Phosphide Alloys

    Science.gov (United States)

    2011-03-01

    spectrum, photoluminescence (PL), and refractive index measurements. Other methods such as infrared imagery and micro probe wavelength dispersing ...States. AFIT/DS/ENP/11-M02 OPTICAL AND ELECTRICAL CHARACTERIZATION OF MELT- GROWN BULK INDIUM GALLIUM ARSENIDE AND INDIUM ARSENIC PHOSPHIDE ...CHARACTERIZATION OF MELT-GROWN BULK INDIUM GALLIUM ARSENIDE AND INDIUM ARSENIC PHOSPHIDE ALLOYS Jean Wei, BS, MS Approved

  3. Internal standard method for determination of gallium and some trace elements in bauxite by neutron activation analysis

    International Nuclear Information System (INIS)

    Chen, S.G.; Tsai, H.T.

    1983-01-01

    A method is described for the determination of gallium and other trace elements such as Ce, Cr, Hf, Lu and Th in bauxite by the technique of neutron activation analysis using gold as internal standard. Isopropyl ether was used as organic extractant radioactive gallium from the sample. This method yields very good accuracy with a relative error of +-3%. (author)

  4. Differentiation of osteomyelitis and infarction in sickle-cell hemoglobinopathies using combined bone-marrow and gallium scanning

    International Nuclear Information System (INIS)

    Hatfield, M.K.; Kahn, C.E.; Ryan, J.W.; Martin, W.B.

    1986-01-01

    The clinical records and scintigrams of patients with sickle cell hemoglobinopathies in whom acute symptoms developed suggestive of possible osteomyelitis and who had undergone sequential Tc-99m bone marrow scans and gallium scintigraphy of the affected sites were reviewed. Osteomyelitis was correctly diagnosed in six of 18 cases when gallium was focally increased relative to a site of decreased or absent bone marrow activity. Of 12 episodes of infarction, both studies showed focally decreased activity in a concordant manner in 11. The remaining, false-positive study indicated slightly increased gallium in 11. The remaining, false-positive indicated slightly increased gallium concentration at a site of decreased bone marrow activity. Overall, a protocol of sequential Tc-99m bone marrow scans and gallium scintigraphy is an effective means of distinguishing osteomyelitis from infarction in patients with sickle cell hemoglobinopathies

  5. The comparison between gallium arsenide and indium gallium arsenide as materials for solar cell performance using Silvaco application

    Energy Technology Data Exchange (ETDEWEB)

    Zahari, Suhaila Mohd; Norizan, Mohd Natashah; Mohamad, Ili Salwani; Osman, Rozana Aina Maulat; Taking, Sanna [School of Microelectronic Engineering, Universiti Malaysia Perlis, Kampus Pauh Putra, 02600 Arau, Perlis (Malaysia)

    2015-05-15

    The work presented in this paper is about the development of single and multilayer solar cells using GaAs and InGaAs in AM1.5 condition. The study includes the modeling structure and simulation of the device using Silvaco applications. The performance in term of efficiency of Indium Gallium Arsenide (InGaAs) and GaAs material was studied by modification of the doping concentration and thickness of material in solar cells. The efficiency of the GaAs solar cell was higher than InGaAs solar cell for single layer solar cell. Single layer GaAs achieved an efficiency about 25% compared to InGaAs which is only 2.65% of efficiency. For multilayer which includes both GaAs and InGaAs, the output power, P{sub max} was 8.91nW/cm² with the efficiency only 8.51%. GaAs is one of the best materials to be used in solar cell as a based compared to InGaAs.

  6. The comparison between gallium arsenide and indium gallium arsenide as materials for solar cell performance using Silvaco application

    Science.gov (United States)

    Zahari, Suhaila Mohd; Norizan, Mohd Natashah; Mohamad, Ili Salwani; Osman, Rozana Aina Maulat; Taking, Sanna

    2015-05-01

    The work presented in this paper is about the development of single and multilayer solar cells using GaAs and InGaAs in AM1.5 condition. The study includes the modeling structure and simulation of the device using Silvaco applications. The performance in term of efficiency of Indium Gallium Arsenide (InGaAs) and GaAs material was studied by modification of the doping concentration and thickness of material in solar cells. The efficiency of the GaAs solar cell was higher than InGaAs solar cell for single layer solar cell. Single layer GaAs achieved an efficiency about 25% compared to InGaAs which is only 2.65% of efficiency. For multilayer which includes both GaAs and InGaAs, the output power, Pmax was 8.91nW/cm² with the efficiency only 8.51%. GaAs is one of the best materials to be used in solar cell as a based compared to InGaAs.

  7. Ohmic contact formation process on low n-type gallium arsenide (GaAs) using indium gallium zinc oxide (IGZO)

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Seong-Uk [Samsung-SKKU Graphene Center and School of Electronics and Electrical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Product and Test Engineering Team, System LSI Division, Samsung Electronics Co., Ltd, Yongin 446-711 (Korea, Republic of); Jung, Woo-Shik [Department of Electrical Engineering, Stanford University, Stanford, CA 94305 (United States); Lee, In-Yeal; Jung, Hyun-Wook; Kim, Gil-Ho [Samsung-SKKU Graphene Center and School of Electronics and Electrical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Park, Jin-Hong, E-mail: jhpark9@skku.edu [Samsung-SKKU Graphene Center and School of Electronics and Electrical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2014-02-01

    Highlights: • We propose a method to fabricate non-gold Ohmic contact on low n-type GaAs with IGZO. • 0.15 A/cm{sup 2} on-current and 1.5 on/off-current ratio are achieved in the junction. • InAs and InGaAs formed by this process decrease an electron barrier height. • Traps generated by diffused O atoms also induce a trap-assisted tunneling phenomenon. - Abstract: Here, an excellent non-gold Ohmic contact on low n-type GaAs is demonstrated by using indium gallium zinc oxide and investigating through time of flight-secondary ion mass spectrometry, X-ray photoelectron spectroscopy, transmission electron microscopy, J–V measurement, and H [enthalpy], S [entropy], Cp [heat capacity] chemistry simulation. In is diffused through GaAs during annealing and reacts with As, forming InAs and InGaAs phases with lower energy bandgap. As a result, it decreases the electron barrier height, eventually increasing the reverse current. In addition, traps generated by diffused O atoms induce a trap-assisted tunneling phenomenon, increasing generation current and subsequently the reverse current. Therefore, an excellent Ohmic contact with 0.15 A/cm{sup 2} on-current density and 1.5 on/off-current ratio is achieved on n-type GaAs.

  8. The comparison between gallium arsenide and indium gallium arsenide as materials for solar cell performance using Silvaco application

    International Nuclear Information System (INIS)

    Zahari, Suhaila Mohd; Norizan, Mohd Natashah; Mohamad, Ili Salwani; Osman, Rozana Aina Maulat; Taking, Sanna

    2015-01-01

    The work presented in this paper is about the development of single and multilayer solar cells using GaAs and InGaAs in AM1.5 condition. The study includes the modeling structure and simulation of the device using Silvaco applications. The performance in term of efficiency of Indium Gallium Arsenide (InGaAs) and GaAs material was studied by modification of the doping concentration and thickness of material in solar cells. The efficiency of the GaAs solar cell was higher than InGaAs solar cell for single layer solar cell. Single layer GaAs achieved an efficiency about 25% compared to InGaAs which is only 2.65% of efficiency. For multilayer which includes both GaAs and InGaAs, the output power, P max was 8.91nW/cm² with the efficiency only 8.51%. GaAs is one of the best materials to be used in solar cell as a based compared to InGaAs

  9. Electrochemical manipulation of localized electrolysis of water: application to determination of gallium by stripping voltammetry

    International Nuclear Information System (INIS)

    Gopinath, N.; Kamat, J.V.; Aggarwal, S.K.

    2003-01-01

    A large enhancement in the stripping peak current of gallium disproportionate to the preconcentration deposition potential, more negative than -1.4 V, was observed in 0.005 M HCl electrolyte. It was attributed to the fact that water was electrolysed and an alkaline environment (OH ions) in the vicinity of the Hg drop electrode was generated. As a result, the Ga +3 ions were hydrolysed and gallate ions were in situ produced. The easy-to-reduce gallate ions were involved in the preconcentration step instead of the difficult-to-reduce Ga + 3 ions. Hence there was an increase in the quantity of gallium deposited / dissolved in the Hg drop electrode. Experimental conditions were optimized for the determination of gallium in 0.005 M HCl electrolyte. (author)

  10. Gallium-Based Room-Temperature Liquid Metals: Actuation and Manipulation of Droplets and Flows

    Directory of Open Access Journals (Sweden)

    Leily Majidi

    2017-08-01

    Full Text Available Gallium-based room-temperature liquid metals possess extremely valuable properties, such as low toxicity, low vapor pressure, and high thermal and electrical conductivity enabling them to become suitable substitutes for mercury and beyond in wide range of applications. When exposed to air, a native oxide layer forms on the surface of gallium-based liquid metals which mechanically stabilizes the liquid. By removing or reconstructing the oxide skin, shape and state of liquid metal droplets and flows can be manipulated/actuated desirably. This can occur manually or in the presence/absence of a magnetic/electric field. These methods lead to numerous useful applications such as soft electronics, reconfigurable devices, and soft robots. In this mini-review, we summarize the most recent progresses achieved on liquid metal droplet generation and actuation of gallium-based liquid metals with/without an external force.

  11. Development of a production scale purification of Ge-68 from irradiated gallium metal

    Energy Technology Data Exchange (ETDEWEB)

    Fitzsimmons, Jonathan M.; Mausner, Leonard [Brookhaven National Laboratory, Upton, NY (United States)

    2015-05-01

    Germanium-68 (Ge-68) is produced by proton irradiation of a gallium metal target and purified by organic extraction. The Ge-68 can be used in a medical isotope generator to produce Gallium-68 (Ga-68) which can be used to radiolabel PET imaging agents. The emerging use of Ge-68 in the Ga-68 medical isotope generator has caused us to develop a new purification method for Ge-68 that does not use toxic solvents. The purpose of this work was to develop a production scale separation of Ge-68 that utilizes a leaching step to remove a bulk of the gallium metal, followed by purification with Sephadex {sup copyright} G25. Production scale (300 mCi) purification was performed with the new method. The purified Ge-68 contained the highest radioactivity concentration of Ge-68 produced at BNL; the sample meet Department of Energy specifications and the method had an excellent recovery of Ge-68.

  12. Gallium-containing polymer brush film as efficient supported Lewis acid catalyst in a glass microreactor

    Directory of Open Access Journals (Sweden)

    Rajesh Munirathinam

    2013-08-01

    Full Text Available Polystyrene sulfonate polymer brushes, grown on the interior of the microchannels in a microreactor, have been used for the anchoring of gallium as a Lewis acid catalyst. Initially, gallium-containing polymer brushes were grown on a flat silicon oxide surface and were characterized by FTIR, ellipsometry, and X-ray photoelectron spectroscopy (XPS. XPS revealed the presence of one gallium per 2–3 styrene sulfonate groups of the polymer brushes. The catalytic activity of the Lewis acid-functionalized brushes in a microreactor was demonstrated for the dehydration of oximes, using cinnamaldehyde oxime as a model substrate, and for the formation of oxazoles by ring closure of ortho-hydroxy oximes. The catalytic activity of the microreactor could be maintained by periodic reactivation by treatment with GaCl3.

  13. Lewis-Acid/Base Effects on Gallium Volatility in Molten Chlorides

    International Nuclear Information System (INIS)

    Williams, D.F.

    2001-01-01

    It has been proposed that GaCl 3 can be removed by direct volatilization from a Pu-Ga alloy that is dissolved in a molten chloride salt. Although pure GaCl 3 is quite volatile (boiling point, 201 C), the behavior of GaCl 3 dissolved in chloride salts is different due to solution effects and is critically dependent on the composition of the solvent salt (i.e., its Lewis-acid/base character). In this report, the behavior of gallium in prototypical Lewis-acid and Lewis-base salts is compared. It was found that gallium volatility is suppressed in basic melts and enhanced in acidic melts. The implications of these results on the potential for simple gallium removal in molten salt systems are significant

  14. 67Gallium citrate scintigraphy to assess metastatic spread in a dog with an oral melanoma.

    Science.gov (United States)

    Liuti, T; de Vos, J; Bosman, T; van de Wiele, C; Grinwis, G C M; van Bree, H; Peremans, K

    2009-01-01

    Gallium scintigraphy was used to evaluate therapeutic response in a 10-year-old, male, Dutch sheepdog, suffering from an oral melanoma. Treatment was performed with a combination of carboplatin and hypofractionated radiation. Nineteen weeks after radiation therapy, the left submandibular lymph node was surgically removed because of metastatic disease. Thirty weeks after radiation therapy, 67Gallium scintigraphy was performed to assess for residual disease and metastasis. Increased uptake in the right submandibular lymph node area was noted and identified as a melanoma metastasis on cytology. Surgical excision was performed. Twenty-one weeks later, the dog was euthanased because of advanced pulmonary metastases. This report of a case of oral melanoma illustrates the advantages of 67Gallium scintigraphy in monitoring for the presence of metastatic disease and effectiveness of therapy.

  15. Gallium scanning in differentiating malignant from benign asbestos-related pleural disease

    International Nuclear Information System (INIS)

    Teirstein, A.S.; Chahinian, P.; Goldsmith, S.J.; Sorek, M.

    1986-01-01

    In order to assess the utility of 67gallium citrate in delineating malignant pleural mesothelioma from benign asbestos-related pleural disease, 49 patients with malignant mesothelioma and 16 with benign asbestos-related pleural disease were studied. Seven patients with malignant mesothelioma had no history of asbestos exposure, while the remaining 58 patients were exposed. Forty-three of the 49 patients (88%) with malignant mesothelioma had a positive 67gallium scan including 36 of the 42 (86%) patients with asbestos exposure and all 7 patients without a history of asbestos exposure. Three of 16 patients (19%) with benign asbestos-related pleural disease had a positive scan. 67Gallium radionuclide imaging is nonspecific but may be valuable in noninvasive monitoring of asbestos-exposed populations, which have a high risk for the late development of benign and/or malignant pleural disease

  16. Natively textured surface hydrogenated gallium-doped zinc oxide transparent conductive thin films with buffer layers for solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xin-liang, E-mail: cxlruzhou@163.com; Wang, Fei; Geng, Xin-hua; Huang, Qian; Zhao, Ying; Zhang, Xiao-dan

    2013-09-02

    Natively textured surface hydrogenated gallium-doped zinc oxide (HGZO) thin films have been deposited via magnetron sputtering on glass substrates. These natively textured HGZO thin films exhibit rough pyramid-like textured surface, high optical transmittances in the visible and near infrared region and excellent electrical properties. The experiment results indicate that tungsten-doped indium oxide (In{sub 2}O{sub 3}:W, IWO) buffer layers can effectively improve the surface roughness and enhance the light scattering ability of HGZO thin films. The root-mean-square roughness of HGZO, IWO (10 nm)/HGZO and IWO (30 nm)/HGZO thin films are 28, 44 and 47 nm, respectively. The haze values at the wavelength of 550 nm increase from 7.0% of HGZO thin film without buffer layer to 18.37% of IWO (10 nm)/HGZO thin film. The optimized IWO (10 nm)/HGZO exhibits a high optical transmittance of 82.18% in the visible and near infrared region (λ ∼ 400–1100 nm) and excellent electrical properties with a relatively low sheet resistance of 3.6 Ω/□ and the resistivity of 6.21 × 10{sup −4} Ωcm. - Highlights: • Textured hydrogenated gallium-doped zinc oxide (HGZO) films were developed. • Tungsten-doped indium oxide (IWO) buffer layers were applied for the HGZO films. • Light-scattering ability of the HGZO films can be improved through buffer layers. • Low sheet resistance and high haze were obtained for the IWO(10 nm)/HGZO film. • The IWO/HGZO films are promising transparent conductive layers for solar cells.

  17. Results of the Gallium-Clad Phase 3 and Phase 4 tasks (canceled prior to completion)

    International Nuclear Information System (INIS)

    Morris, R.N.

    1998-08-01

    This report summarizes the results of the Gallium-Clad interactions Phase 3 and 4 tasks. Both tasks were to involve examining the out-of-pile stability of residual gallium in short fuel rods with an imposed thermal gradient. The thermal environment was to be created by an electrical heater in the center of the fuel rod and coolant flow on the rod outer cladding. Both tasks were canceled due to difficulties with fuel pellet fabrication, delays in the preparation of the test apparatus, and changes in the Fissile Materials Disposition program budget

  18. Steroid-induced suppression of gallium uptake in tumors of the central nervous system: concise communication

    International Nuclear Information System (INIS)

    Waxman, A.D.; Beldon, J.R.; Richli, W.; Tanasescu, D.E.; Siemsen, J.K.

    1978-01-01

    The effect of steroids given in greater than replacement doses on the gallium and technetium glucoheptonate brain scan is evaluated by comparing the relative sensitivity of both radiopharmaceuticals in patients both on and off steroids. The study shows a significant steroid effect on the sensitivity of 95% to 64% following steroids. Steroids did not significantly alter the sensitivity of the technetium glucoheptonate study. The superiority of the TcGH brain scan over the gallium citrate brain scan in the steroid population suggests a difference in the uptake mechanism for the two radiopharmaceuticals

  19. Properties of gallium arsenide alloyed with Ge and Se by irradiation in nuclear reactor thermal column

    International Nuclear Information System (INIS)

    Kolin, N.G.; Osvenskij, V.B.; Tokarevskij, V.V.; Kharchenko, V.A.; Ievlev, S.M.

    1985-01-01

    Dependences of electrophysical properties as well as lattice unit spacing and density of nuclear-alloyed gallium arsenide on the fluence of reactor neutrons and heat treatment are investigated. Neutron radiation of gallium arsenide with different energy spectra is shown to differently affect material properties. Fast neutrons make the main contribution to defect formation. Concentration of compensating acceptor defects formed under GaAs radiation in a thermal column practically equals concentration of introduced donor impurities. Radiation defects of acceptor type are not annealed in the material completely even at 900-1000 deg C

  20. Spectral and luminescence properties of Cr(3+) ad Nd(3+) ions in gallium garnet crystals

    Science.gov (United States)

    Denisov, A. L.; Ostroumov, V. G.; Saidov, Z. S.; Smirnov, V. A.; Shcherbakov, I. A.

    1986-01-01

    The effective peak stimulated-emission cross section of chromium-doped gadolinium-scandium-gallium garnets (GSGG) has been determined to be 8.5 x 10 to the -21st sq cm at room temperature. The values of the energy-gap Delta E(2E-4T2) chromim fluorescence lifetime and the chromium to neodymium energy-transfer parameter C(DA) (Cr-Nd) are determined for several gallium garnets. Temperature-dependent absorption and luminescence spectra of neodymium-doped GGG and GSGG are reported and discussed in the context of their use as laser materials.

  1. Semi-quantitative evaluation of gallium-67 scintigraphy in lupus nephritis

    Energy Technology Data Exchange (ETDEWEB)

    Lin Wanyu [Dept. of Nuclear Medicine, Taichung Veterans General Hospital, Taichung (Taiwan); Dept. of Radiological Technology, Chung-Tai College of Medical Technology, Taichung (Taiwan); Hsieh Jihfang [Section of Nuclear Medicine, Chi-Mei Foundation Hospital, Yunk Kang City, Tainan (Taiwan); Tsai Shihchuan [Dept. of Nuclear Medicine, Show Chwan Memorial Hospital, Changhua (Taiwan); Lan Joungliang [Dept. of Internal Medicine, Taichung Veterans General Hospital, Taichung (Taiwan); Cheng Kaiyuan [Dept. of Radiological Technology, Chung-Tai College of Medical Technology, Taichung (Taiwan); Wang Shyhjen [Dept. of Nuclear Medicine, Taichung Veterans General Hospital, Taichung (Taiwan)

    2000-11-01

    Within nuclear medicine there is a trend towards quantitative analysis. Gallium renal scan has been reported to be useful in monitoring the disease activity of lupus nephritis. However, only visual interpretation using a four-grade scale has been performed in previous studies, and this method is not sensitive enough for follow-up. In this study, we developed a semi-quantitative method for gallium renal scintigraphy to find a potential parameter for the evaluation of lupus nephritis. Forty-eight patients with lupus nephritis underwent renal biopsy to determine World Health Organization classification, activity index (AI) and chronicity index (CI). A delayed 48-h gallium scan was also performed and interpreted by visual and semi-quantitative methods. For semi-quantitative analysis of the gallium uptake in both kidneys, regions of interest (ROIs) were drawn over both kidneys, the right forearm and the adjacent spine. The uptake ratios between these ROIs were calculated and expressed as the ''kidney/spine ratio (K/S ratio)'' or the ''kidney/arm ratio (K/A ratio)''. Spearman's rank correlation test and Mann-Whitney U test were used for statistical analysis. Our data showed a good correlation between the semi-quantitative gallium scan and the results of visual interpretation. K/S ratios showed a better correlation with AI than did K/A ratios. Furthermore, the left K/S ratio displayed a better correlation with AI than did the right K/S ratio. In contrast, CI did not correlate well with the results of semi-quantitative gallium scan. In conclusion, semi-quantitative gallium renal scan is easy to perform and shows a good correlation with the results of visual interpretation and renal biopsy. The left K/S ratio from semi-quantitative renal gallium scintigraphy displays the best correlation with AI and is a useful parameter in evaluating the disease activity in lupus nephritis. (orig.)

  2. Gallium-SPECT in the detection of prosthetic valve endocarditis and aortic ring abscess

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, K.; Barnes, D.; Martin, R.H.; Rae, J.R. (Department of Diagnostic Radiology, Victoria General Hospital Halifax, Nova Scotia (Canada))

    1991-09-01

    A 52-yr-old man who had a bioprosthetic aortic valve developed Staphylococcus aureus bacteremia. Despite antibiotic therapy he had persistent pyrexia and developed new conduction system disturbances. Echocardiography did not demonstrate vegetations on the valve or an abscess, but gallium scintigraphy using SPECT clearly identified a focus of intense activity in the region of the aortic valve. The presence of valvular vegetations and a septal abscess was confirmed at autopsy. Gallium scintigraphy, using SPECT, provided a useful noninvasive method for the demonstration of endocarditis and the associated valve ring abscess.

  3. Gallium-SPECT in the detection of prosthetic valve endocarditis and aortic ring abscess

    International Nuclear Information System (INIS)

    O'Brien, K.; Barnes, D.; Martin, R.H.; Rae, J.R.

    1991-01-01

    A 52-yr-old man who had a bioprosthetic aortic valve developed Staphylococcus aureus bacteremia. Despite antibiotic therapy he had persistent pyrexia and developed new conduction system disturbances. Echocardiography did not demonstrate vegetations on the valve or an abscess, but gallium scintigraphy using SPECT clearly identified a focus of intense activity in the region of the aortic valve. The presence of valvular vegetations and a septal abscess was confirmed at autopsy. Gallium scintigraphy, using SPECT, provided a useful noninvasive method for the demonstration of endocarditis and the associated valve ring abscess

  4. Thermal Cycling and High Temperature Reverse Bias Testing of Control and Irradiated Gallium Nitride Power Transistors

    Science.gov (United States)

    Patterson, Richard L.; Boomer, Kristen T.; Scheick, Leif; Lauenstein, Jean-Marie; Casey, Megan; Hammoud, Ahmad

    2014-01-01

    The power systems for use in NASA space missions must work reliably under harsh conditions including radiation, thermal cycling, and exposure to extreme temperatures. Gallium nitride semiconductors show great promise, but information pertaining to their performance is scarce. Gallium nitride N-channel enhancement-mode field effect transistors made by EPC Corporation in a 2nd generation of manufacturing were exposed to radiation followed by long-term thermal cycling and testing under high temperature reverse bias conditions in order to address their reliability for use in space missions. Result of the experimental work are presented and discussed.

  5. Solar neutrino results from SAGE

    International Nuclear Information System (INIS)

    Gavrin, V.N.

    2001-01-01

    The results of ten years of solar neutrino observation by the Russian-American gallium solar neutrino experiment (SAGE) are reported. The overall result of 70 runs during the measurement period from January 1990 to October 1999 is 75.4 -6.8 +7.0 (stat.) -3.0 +3.5 (syst) SNU. This represents only slightly more than half of the predicted standard solar model rate of 129 SNU. The individual results on each run, and the results of combined analysis of all runs during each year, as well as the results of combined analysis of all runs during monthly and bimonthly periods are presented

  6. Solar neutrino results from SAGE

    International Nuclear Information System (INIS)

    Gavrin, V.N.

    2000-01-01

    We report the results of ten years of solar neutrino observation by the Russian-American Gallium solar neutrino Experiment (SAGE). The overall result of 70 runs during the measurement period January 1990 to October 1999 is 75.4 + 7.0/-6.8 (stat.) +3.5/-3.0 (syst.) SNU. This represents only slightly more than half of the predicted standard solar model rate of 129 SNU. The individual results of each run, and the results of combined analysis of all runs during each year, as well as the results of combined analysis of all runs during monthly and bimonthly periods are presented

  7. Photoelectrochemical etching of gallium nitride surface by complexation dissolution mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Miao-Rong [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 215123 Suzhou (China); University of Chinese Academy of Sciences, 100049 Beijing (China); Hou, Fei; Wang, Zu-Gang; Zhang, Shao-Hui [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 215123 Suzhou (China); Changchun University of Science and Technology, 130022 Changchun (China); Pan, Ge-Bo, E-mail: gbpan2008@sinano.ac.cn [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 215123 Suzhou (China)

    2017-07-15

    Graphical abstract: GaN surface was etched by 0.3 M EDTA-2Na. The proposed complexation dissolution mechanism can be applicable to almost all neutral etchants under the prerequisite of strong light and electric field. - Highlights: • GaN surface was etched by EDTA-2Na. • GaN may be dissolved into EDTA-2Na by forming Ga–EDTA complex. • We propose the complexation dissolution mechanism for the first time. - Abstract: Gallium nitride (GaN) surface was etched by 0.3 M ethylenediamine tetraacetic acid disodium (EDTA-2Na) via photoelectrochemical etching technique. SEM images reveal the etched GaN surface becomes rough and irregular. The pore density is up to 1.9 × 10{sup 9} per square centimeter after simple acid post-treatment. The difference of XPS spectra of Ga 3d, N 1s and O 1s between the non-etched and freshly etched GaN surfaces can be attributed to the formation of Ga–EDTA complex at the etching interface between GaN and EDTA-2Na. The proposed complexation dissolution mechanism can be broadly applicable to almost all neutral etchants under the prerequisite of strong light and electric field. From the point of view of environment, safety and energy, EDTA-2Na has obvious advantages over conventionally corrosive etchants. Moreover, as the further and deeper study of such nearly neutral etchants, GaN etching technology has better application prospect in photoelectric micro-device fabrication.

  8. Analysis on the Performance of Copper Indium Gallium Selenide (CIGS Based Photovoltaic Thermal

    Directory of Open Access Journals (Sweden)

    Zulkepli Afzam

    2016-01-01

    Full Text Available This paper deals with the efficiency improvement of Copper Indium Gallium Selenide (CIGS Photovoltaic (PV and also solar thermal collector. Photovoltaic thermal (PV/T can improve overall efficiency for PV and also solve the problem of limited roof space at urban area. Objective of this study is to clarify the effect of mass flow rate on the efficiency of the PV/T system. A CIGS solar cell is used with rated output power 65 W and 1.18 m2 of area. 4 set of experiments were carried out, which were: thermal collector with 0.12 kg/s flow rate, PV/T with 0.12 kg/s flow rate, PV/T with 0.09 kg/s flow rate and PV. It was found that PV/T with 0.12 kg/s flow rate had the highest electrical efficiency, 2.92 %. PV/T with 0.09 kg/s flow rate had the lowest electrical efficiency, 2.68 %. It also had 2 % higher overall efficiency. The efficiency gained is low due to several factors. The rated output power of the PV is low for the area of 1.18 m2. The packing factor of the PV also need to be considered as it may not be operated at the optimal packing factor. Furthermore, aluminium sheet of the PV may affect the PV temperature due to high thermal conductivity. Further study on more values of mass flow rate and also other parameters that affect the efficiency of the PV/T is necessary.

  9. Group 13 ligand supported heavy-metal complexes: first structural evidence for gallium-lead and gallium-mercury bonds.

    Science.gov (United States)

    Prabusankar, Ganesan; Gemel, Christian; Winter, Manuela; Seidel, Rüdiger W; Fischer, Roland A

    2010-05-25

    Heavy-metal complexes of lead and mercury stabilized by Group 13 ligands were derived from the oxidative addition of Ga(ddp) (ddp=HC(CMeNC(6)H(3)-2,6-iPr(2))(2), 2-diisopropylphenylamino-4-diisopropyl phenylimino-2-pentene) with corresponding metal precursors. The reaction of Me(3)PbCl and Ga(ddp) afforded compound [{(ddp)Ga(Cl)}PbMe(3)] (1) composed of Ga-Pb(IV) bonds. In addition, the monomeric plumbylene-type compound [{(ddp)Ga(OSO(2)CF(3))}(2)Pb(thf)] (2a) with an unsupported Ga-Pb(II)-Ga linkage was obtained by the reaction of [Pb(OSO(2)CF(3))(3)] with Ga(ddp) (2 equiv). Compound 2a falls under the rare example of a discrete plumbylene-type compound supported by a nonclassical ligand. Interesting structural changes were observed when [Pb(OSO(2)CF(3))(3)]2.H(2)O was treated with Ga(ddp) in a 1:2 ratio to yield [{(ddp)Ga(mu-OSO(2)CF(3))}(2)(OH(2))Pb] (2b) at below -10 degrees C. Compound 2b consists of a bent Ga-Pb-Ga backbone with a bridging triflate group between the Ga-Pb bond and a weakly interacting water molecule at the gallium center. Similarly, the reaction of mercury thiolate Hg(SC(6)F(5)) with Ga(ddp) (2 equiv) produced the bimetallic homoleptic compounds anti-[{(ddp)Ga(SC(6)F(5))}(2)Hg] (3a) and gauche-[{(ddp)Ga(SC(6)F(5))}(2)Hg] (3b), respectively, with a linear Ga-Hg-Ga linkage. Compounds 1-3 were structurally characterized and these are the first examples of compounds comprised of Ga-Pb(II), Ga-Pb(IV), and Ga-Hg bonds.

  10. Gallium-cladding compatibility testing plan: Phase 3: Test plan for centrally heated surrogate rodlet test. Revision 2

    International Nuclear Information System (INIS)

    Morris, R.N.; Baldwin, C.A.; Wilson, D.F.

    1998-07-01

    The Fissile Materials Disposition Program (FMDP) is investigating the use of weapons grade plutonium in mixed oxide (MOX) fuel for light-water reactors (LWR). Commercial MOX fuel has been successfully used in overseas reactors for many years; however, weapons derived fuel may differ from the previous commercial fuels because of small amounts of gallium impurities. A concern presently exists that the gallium may migrate out of the fuel, react with and weaken the clad, and thereby promote loss of fuel pin integrity. Phases 1 and 2 of the gallium task are presently underway to investigate the types of reactions that occur between gallium and clad materials. This is a Level-2 document as defined in the Fissile Materials Disposition Program Light-Water Reactor Mixed-Oxide Fuel Irradiation Test Project Plan. This Plan summarizes the projected Phase 3 Gallium-Cladding compatibility heating test and the follow-on post test examination (PTE). This work will be performed using centrally-heated surrogate pellets, to avoid unnecessary complexities and costs associated with working with plutonium and an irradiation environment. Two sets of rodlets containing pellets prepared by two different methods will be heated. Both sets will have an initial bulk gallium content of approximately 10 ppm. The major emphasis of the PTE task will be to examine the material interactions, particularly indications of gallium transport from the pellets to the clad

  11. Hydrogen Production from Water by Photolysis, Sonolysis and Sonophotolysis with Solid Solutions of Rare Earth, Gallium and Indium Oxides as Heterogeneous Catalysts

    Directory of Open Access Journals (Sweden)

    Marta Penconi

    2015-07-01

    Full Text Available In this work, we present the hydrogen production by photolysis, sonolysis and sonophotolysis of water in the presence of newly synthesized solid solutions of rare earth, gallium and indium oxides playing as catalysts. From the experiments of photolysis, we found that the best photocatalyst is the solid solution Y0.8Ga0.2InO3 doped by sulphur atoms. In experiments of sonolysis, we optimized the rate of hydrogen production by changing the amount of water, adding ethanol and tuning the power of our piezoelectric transducer. Finally, we performed sonolysis and sonophotolysis experiments in the presence of S:Y0.8Ga0.2InO3 finding a promising synergistic effect of UV-visible electromagnetic waves and 38 kHz ultrasound waves in producing H2.

  12. Vibrational spectra of the cyanodimethylmetal complexes of magnesium, aluminium, gallium, and indium

    International Nuclear Information System (INIS)

    Mueller, J.; Schmock, F.; Klopsch, A.; Dehnicke, K.

    1975-01-01

    Tetramethylammonium cyanide reacts with an ethereal solution of dimethylmagnesium to form [NMe 4 ] 4 [Me 2 MgCN] 4 , the complex anion of which is isoelectronic with the known tetrameric dimethylaluminium cyanide [Me 2 AlCN] 4 . The vibrational spectra are reported together with those of the corresponding gallium and indium compounds. (orig.) [de

  13. Bilateral Comparison of Mercury and Gallium Fixed-Point Cells Using Standard Platinum Resistance Thermometer

    Science.gov (United States)

    Bojkovski, J.; Veliki, T.; Zvizdić, D.; Drnovšek, J.

    2011-08-01

    The objective of project EURAMET 1127 (Bilateral comparison of triple point of mercury and melting point of gallium) in the field of thermometry is to compare realization of a triple point of mercury (-38.8344 °C) and melting point of gallium (29.7646 °C) between the Slovenian national laboratory MIRS/UL-FE/LMK and the Croatian national laboratory HMI/FSB-LPM using a long-stem 25 Ω standard platinum resistance thermometer (SPRT). MIRS/UL/FE-LMK participated in a number of intercomparisons on the level of EURAMET. On the other hand, the HMI/LPM-FSB laboratory recently acquired new fixed-point cells which had to be evaluated in the process of intercomparisons. A quartz-sheathed SPRT has been selected and calibrated at HMI/LPM-FSB at the triple point of mercury, the melting point of gallium, and the water triple point. A second set of measurements was made at MIRS/UL/FE-LMK. After its return, the SPRT was again recalibrated at HMI/LPM-FSB. In the comparison, the W value of the SPRT has been used. Results of the bilateral intercomparison confirmed that the new gallium cell of the HMI/LPM-FSB has a value that is within uncertainty limits of both laboratories that participated in the exercise, while the mercury cell experienced problems. After further research, a small leakage in the mercury fixed-point cell has been found.

  14. Peculiarities of electrooptical characteristics of gallium phosphide light-emitting diodes in high injection level conditions

    Directory of Open Access Journals (Sweden)

    O. M. Hontaruk

    2015-04-01

    Full Text Available Electroluminescence of green N-doped gallium phosphide light-emitting diodes was studied. The negative differential resistance region in the current-voltage characteristics was found at low temperature (Т ≤ 90 К. Possible reason of this phenomenon is the redistribution of recombinational flows between annihilation channels on isolated nitrogen atoms and annihilation channel on the NN1 pairs.

  15. Gallium nitrate inhibits calcium resorption from bone and is effective treatment for cancer-related hypercalcemia

    International Nuclear Information System (INIS)

    Warrell, R.P. Jr.; Bockman, R.S.; Coonley, C.J.; Isaacs, M.; Staszewski, H.

    1984-01-01

    Approximately two-thirds of patients who receive the anticancer drug gallium nitrate develop mild hypocalcemia. To evaluate the mechanism of drug-induced hypocalcemia, we tested the effects of gallium nitrate upon in vitro release of 45 Ca++ from explanted fetal rat bones. The drug significantly inhibited 45 Ca++ release in response to stimulation with both parathyroid hormone and a lymphokine preparation with osteoclast activating factor activity. The inhibitory effects on bone resorption were both time- and dose-dependent. Later, in a pilot study, we treated 10 patients who had cancer-related hypercalcemia with gallium nitrate administered by continuous infusion. All patients responded by a reduction of total serum calcium to normal or subnormal concentrations (13.8 +/- 1.05 mg/dl, mean +/- SD pretreatment, to 8.03 +/- 1.03 mg/dl, mean posttreatment nadir). Our results indicate that gallium nitrate effectively treats cancer-related hypercalcemia and that it probably acts by inhibiting calcium release from bone

  16. Gallium-67 imaging in a patient with paracoccidioidomycosis: a case report

    International Nuclear Information System (INIS)

    Teixeira, Ana Beatriz Marinho de Jesus; Etchebehere, Elba Cristina Sa de Camargo; Lima, Mariana Cunha Lopes de; Santos, Allan de Oliveira; Pires, Bruno Cunha; Valenca Junior, Jose Telmo; Ramos, Celso Dario; Camargo, Edwaldo E.

    2000-01-01

    A 26 year-old female was admitted with abdominal pain, fever and weight loss. The clinical and laboratory investigations led to the diagnosis of paracoccidioidomycosis. Gallium-67 whole body images correlated well with the clinical course of the disease and with the patient's prognosis. (author)

  17. Gallium-67 imaging in a patient with paracoccidioidomycosis: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, Ana Beatriz Marinho de Jesus; Etchebehere, Elba Cristina Sa de Camargo; Lima, Mariana Cunha Lopes de; Santos, Allan de Oliveira; Pires, Bruno Cunha; Valenca Junior, Jose Telmo; Ramos, Celso Dario; Camargo, Edwaldo E. [Universidade Estadual de Campinas, SP (Brazil). Hospital das Clinicas. Servico de Medicina Nuclear]. E-mail: elba@mn-d.com

    2000-06-01

    A 26 year-old female was admitted with abdominal pain, fever and weight loss. The clinical and laboratory investigations led to the diagnosis of paracoccidioidomycosis. Gallium-67 whole body images correlated well with the clinical course of the disease and with the patient's prognosis. (author)

  18. Nature of gallium focused ion beam induced phase transformation in 316L austenitic stainless steel

    International Nuclear Information System (INIS)

    Babu, R. Prasath; Irukuvarghula, S.; Harte, A.; Preuss, M.

    2016-01-01

    The microstructural evolution and chemistry of the ferrite phase (α), which transforms from the parent austenite phase (γ) of 316L stainless steel during gallium (Ga) ion beam implantation in Focused Ion Beam (FIB) instrument was systematically studied as a function of Ga"+ ion dose and γ grain orientations. The propensity for initiation of γ → α phase transformation was observed to be strongly dependent on the orientation of the γ grain with respect to the ion beam direction and correlates well with the ion channelling differences in the γ orientations studied. Several α variants formed within a single γ orientation and the sputtering rate of the material, after the γ → α transformation, is governed by the orientation of α variants. With increased ion dose, there is an evolution of orientation of the α variants towards a variant of higher Ga"+ channelling. Unique topographical features were observed within each specific γ orientation that can be attributed to the orientation of defects formed during the ion implantation. In most cases, γ and α were related by either Kurdjumov-Sachs (KS) or Nishiyama-Wassermann (NW) orientation relationship (OR) while in few, no known OR's were identified. While our results are consistent with gallium enrichment being the cause for the γ → α phase transformation, some observations also suggest that the strain associated with the presence of gallium atoms in the lattice has a far field stress effect that promotes the phase transformation ahead of gallium penetration.

  19. Properties of Er and Yb Doped Gallium nitride layers fabricated by magnetron sputtering

    Czech Academy of Sciences Publication Activity Database

    Prajzler, V.; Burian, Z.; Hüttel, I.; Špirková, J.; Hamáček, J.; Oswald, J.; Zavadil, Jiří; Peřina, Vratislav

    2006-01-01

    Roč. 46, č. 6 (2006), s. 49-55 ISSN 1210-2709 R&D Projects: GA ČR(CZ) GA102/06/0424 Institutional research plan: CEZ:AV0Z20670512; CEZ:AV0Z10480505 Keywords : fluorescence * gallium * rare earth compounds Subject RIV: BM - Solid Matter Physics ; Magnetism

  20. 29Si MAS NMR for the zeolite Y - gallium oxide system

    International Nuclear Information System (INIS)

    Sulikowski, B.; Derewinski, M.; Olejniczak, Z.; Segnowski, S.

    1994-01-01

    Wide-pore zeolites modified by gallium oxide has been prepared for catalytic use. Its physico-chemical and catalytic properties have been studied. The structure changes of the catalyst have been investigated by means of MAS NMR spectroscopy. Spectra of 29 Si has been described and discussed

  1. Low temperature growth of gallium oxide thin films via plasma enhanced atomic layer deposition

    NARCIS (Netherlands)

    O'Donoghue, R.; Rechmann, J.; Aghaee, M.; Rogalla, D.; Becker, H.-W.; Creatore, M.; Wieck, A.D.; Devi, A.P.K.

    2017-01-01

    Herein we describe an efficient low temperature (60–160 °C) plasma enhanced atomic layer deposition (PEALD) process for gallium oxide (Ga2O3) thin films using hexakis(dimethylamido)digallium [Ga(NMe2)3]2 with oxygen (O2) plasma on Si(100). The use of O2 plasma was found to have a significant

  2. Gallium/sup 67/ scintigraphy in fibrinous pericarditis associated with bacterial endocarditis

    Energy Technology Data Exchange (ETDEWEB)

    Martin, P; Verhas, M; Devriendt, J; Goffin, Y

    1982-04-01

    An 80-year-old man presented with pyrexia, progressive cardiac failure and inflammation. A diagnosis of pericarditis associated with bacterial endocarditis was suggested from Gallium 67 scintigraphy and confirmed at autopsy. This case of fibrinous pericarditis without effusion could not be diagnosed by echography or routine cardiopulmonary scintigraphy.

  3. Noise suppression and long-range exchange coupling for gallium arsenide spin qubits

    DEFF Research Database (Denmark)

    Malinowski, Filip

    This thesis presents the results of the experimental study performed on spin qubits realized in gate-defined gallium arsenide quantum dots, with the focus on noise suppression and long-distance coupling. First, we show that the susceptibility to charge noise can be reduced by reducing the gradien...

  4. First heats of cerium solution in liquid aluminium, gallium, indium, tin, lead and bismuth

    International Nuclear Information System (INIS)

    Yamshchikov, L.F.; Lebedev, V.A.; Nichkov, I.F.; Raspopin, S.P.; Shein, V.G.

    1983-01-01

    Cerium solution heats in liquid alluminium, gallium, indium, tin, lead and bismuth are determined in high temperature mixing calorimeter with an isothermal shell. The statistical analysis carried out proves that values of cerium solution heat in fusible metals obtained by the methods of electric motive forces and calorimety give a satisfactory agreement

  5. Continuum modelling of silicon diffusion in indium gallium arsenide

    Science.gov (United States)

    Aldridge, Henry Lee, Jr.

    A possible method to overcome the physical limitations experienced by continued transistor scaling and continue improvements in performance and power consumption is integration of III-V semiconductors as alternative channel materials for logic devices. Indium Gallium Arsenide (InGaAs) is such a material from the III-V semiconductor family, which exhibit superior electron mobilities and injection velocities than that of silicon. In order for InGaAs integration to be realized, contact resistances must be minimized through maximizing activation of dopants in this material. Additionally, redistribution of dopants during processing must be clearly understood and ultimately controlled at the nanometer-scale. In this work, the activation and diffusion behavior of silicon, a prominent n-type dopant in InGaAs, has been characterized and subsequently modelled using the Florida Object Oriented Process and Device Simulator (FLOOPS). In contrast to previous reports, silicon exhibits non-negligible diffusion in InGaAs, even for smaller thermal budget rapid thermal anneals (RTAs). Its diffusion is heavily concentration-dependent, with broadening "shoulder-like" profiles when doping levels exceed 1-3x1019cm -3, for both ion-implanted and Molecular Beam Epitaxy (MBE)-grown cases. Likewise a max net-activation value of ˜1.7x1019cm -3 is consistently reached with enough thermal processing, regardless of doping method. In line with experimental results and several ab-initio calculation results, rapid concentration-dependent diffusion of Si in InGaAs and the upper limits of its activation is believed to be governed by cation vacancies that serve as compensating defects in heavily n-type regions of InGaAs. These results are ultimately in line with an amphoteric defect model, where the activation limits of dopants are an intrinsic limitation of the material, rather than governed by individual dopant species or their methods of incorporation. As a result a Fermi level dependent point

  6. Gadopentate interference in gallium-67 tumour imaging: fact or fiction?

    International Nuclear Information System (INIS)

    Baker, R.J.

    1998-01-01

    Full text: Gallium-67-citrate is the most widely used tumour imaging radiopharmaceutical. It is known that the metal ions Sc(III), Au(III), FE(III) and inactive Ga(III), as well as chemotherapy, interfere leading to poor quality scans, characterised by pronounced bone uptake and loss of tumour avidity. In 1990, Hattner and White reported a scan of this nature following administration of the paramagnetic contrast agent gadolinium-DTPA (Gadopentate). Suggestions to account for these changes included in vivo dissociation or the presence of free DTPA in the formulation. Since the use of MRI is increasing dramatically, this potential interference is a vital issue for nuclear medicine. To investigate this phenomenon, gadolinium-DTPA solutions were prepared containing Gd and DTPA in the molar ratios 0.9:1, 1.0:1 and 1.1:1. Their effect on 67 Ga biodistribution at 24 h was investigated using mature female Balb/c mice after i.v. 67 Ga-citrate, injected 4 h after i.v. GD-DTPA. The model was verified by identical studies using inactive GA(III) and FE(III) at 0. 1 mmol/kg. The effects of GD(III) and DTPA ligand at this dose were also determined . Following administration of GD-DTPA up to 0.5 mmol/kg, no significant changes in 67 Ga biodistribution were observed. Minor changes occurred after 0. 1 mmol/kg Gd(III), notably increased renal (49%) and splenic (92%) uptake. With free DTPA, slightly higher blood (33%) and bone (22%) levels were found, but other tissues were not affected. These differences are unable to account for the marked scan changes reported above. However, inactive GA(III) and FE(III) caused a reduction of 67 Ga in all tissues except bone. It is concluded that GD-DTPA or its constituents do not significantly alter the biodistribution of 67 Ga-citrate in mice. The reported scan changes may be the result of extensive chemotherapy

  7. As-Grown Gallium Nitride Nanowire Electromechanical Resonators

    Science.gov (United States)

    Montague, Joshua R.

    Technological development in recent years has led to a ubiquity of micro- and nano-scale electromechanical devices. Sensors for monitoring temperature, pressure, mass, etc., are now found in nearly all electronic devices at both the industrial and consumer levels. As has been true for integrated circuit electronics, these electromechanical devices have continued to be scaled down in size. For many nanometer-scale structures with large surface-to-volume ratio, dissipation (energy loss) becomes prohibitively large causing a decreasing sensitivity with decreasing sensor size. In this work, gallium nitride (GaN) nanowires are investigated as singly-clamped (cantilever) mechanical resonators with typical mechanical quality factors, Q (equal to the ratio of resonance frequency to peak full-width-at-half-maximum-power) and resonance frequencies, respectively, at or above 30,000, and near 1 MHz. These Q values---in vacuum at room temperature---indicate very low levels of dissipation; they are essentially the same as those for bulk quartz crystal resonators that form the basis of simple clocks and mass sensors. The GaN nanowires have lengths and diameters, respectively, of approximately 15 micrometers and hundreds of nanometers. As-grown GaN nanowire Q values are larger than other similarly-sized, bottom-up, cantilever resonators and this property makes them very attractive for use as resonant sensors. We demonstrate the capability of detecting sub-monolayer levels of atomic layer deposited (ALD) films, and the robust nature of the GaN nanowires structure that allows for their 'reuse' after removal of such layers. In addition to electron microscope-based measurement techniques, we demonstrate the successful capacitive detection of a single nanowire using microwave homodyne reflectometry. This technique is then extended to allow for simultaneous measurements of large ensembles of GaN nanowires on a single sample, providing statistical information about the distribution of

  8. Growth of AlGaN under the conditions of significant gallium evaporation: phase separation and enhanced lateral growth

    OpenAIRE

    Mayboroda, I. O.; Knizhnik, A. A.; Grishchenko, Yu. V.; Ezubchenko, I. S.; Zanaveskin, Maxim L.; Presniakov, M. Yu.; Potapkin, B. V.; Ilyin, V. A.

    2017-01-01

    Growth kinetics of AlGaN in NH3 MBE under significant Ga desorption was studied. It was found that the addition of gallium stimulates 2D growth and provides better morphology of films compared to pure AlN. The effect was experimentally observed at up to 98% desorption of the impinging gallium. We found that, under the conditions of significant thermal desorption, larger amounts of gallium were retained at lateral boundaries of 3D surface features than at flat terraces because of the higher bi...

  9. Extraction And Separation Of GALLIUM With Tributyl Phosphate From The Chloride Leach Liquor Of GATTAR Granite, Eastern Desert, Egypt

    International Nuclear Information System (INIS)

    MAHDY, M.A.; MAHMOUD, K.F.; ABD EL-HAMEED, A.M.; ZAHRAN, M.A.

    2009-01-01

    The studied optimum conditions for gallium extraction have confirmed that more than 98.5% of the gallium present in HCl leach liquor of Gattar granite was extracted using 10 % tributyl phosphate (TBP) solvent concentration (v/v) in kerosene as diluent, 15 min shaking time and 1 : 3 organic/ aqueous ratio. About 96 % of the extracted gallium has been stripped from the organic solvent using 0.04 M HCl as aqueous stripping solution. The obtained data clarify that the optimum stripping conditions include 4 min shaking time and 2 : 1 organic/ aqueous ratio.

  10. Preconceptual design for separation of plutonium and gallium by ion exchange

    International Nuclear Information System (INIS)

    DeMuth, S.F.

    1997-01-01

    The disposition of plutonium from decommissioned nuclear weapons, by incorporation into commercial UO 2 -based nuclear reactor fuel, is a viable means to reduce the potential for theft of excess plutonium. This fuel, which would be a combination of plutonium oxide and uranium oxide, is referred to as a mixed oxide (MOX). Following power generation in commercial reactors with this fuel, the remaining plutonium would become mixed with highly radioactive fission products in a spent fuel assembly. The radioactivity, complex chemical composition, and large size of this spent fuel assembly, would make theft difficult with elaborate chemical processing required for plutonium recovery. In fabricating the MOX fuel, it is important to maintain current commercial fuel purity specifications. While impurities from the weapons plutonium may or may not have a detrimental affect on the fuel fabrication or fuel/cladding performance, certifying the effect as insignificant could be more costly than purification. Two primary concerns have been raised with regard to the gallium impurity: (1) gallium vaporization during fuel sintering may adversely affect the MOX fuel fabrication process, and (2) gallium vaporization during reactor operation may adversely affect the fuel cladding performance. Consequently, processes for the separation of plutonium from gallium are currently being developed and/or designed. In particular, two separation processes are being considered: (1) a developmental, potentially lower cost and lower waste, thermal vaporization process following PuO 2 powder preparation, and (2) an off-the-shelf, potentially higher cost and higher waste, aqueous-based ion exchange (IX) process. While it is planned to use the thermal vaporization process should its development prove successful, IX has been recommended as a backup process. This report presents a preconceptual design with material balances for separation of plutonium from gallium by IX

  11. Structure and Properties of Epitaxial Dielectrics on gallium nitride

    Science.gov (United States)

    Wheeler, Virginia Danielle

    GaN is recognized as a possible material for metal oxide semiconductor field effect transistors (MOSFETs) used in high temperature, high power and high speed electronic applications. However, high gate leakage and low device breakdown voltages limit their use in these applications. The use of high-kappa dielectrics, which have both a high permittivity (ε) and high band gap energy (Eg), can reduce the leakage current density that adversely affects MOS devices. La2O3 and Sc2O 3 are rare earth oxides with a large Eg (6.18 eV and 6.3 eV respectively) and a relatively high ε (27 and 14.1 respectively), which make them good candidates for enhancing MOSFET performance. Epitaxial growth of oxides is a possible approach to reducing leakage current and Fermi level pinning related to a high density of interface states for dielectrics on compound semiconductors. In this work, La2O3 and Sc2O 3 were characterized structurally and electronically as potential epitaxial gate dielectrics for use in GaN based MOSFETs. GaN surface treatments were examined as a means for additional interface passivation and influencing subsequent oxide formation. Potassium persulfate (K2(SO4)2) and potassium hydroxide (KOH) were explored as a way to achieve improved passivation and desired surface termination for GaN films deposited on sapphire substrates by metal organic chemical vapor deposition (MOCVD). X-ray photoelectron spectroscopy (XPS) showed that KOH left a nitrogen-rich interface, while K2(SO 4)2 left a gallium-rich interface, which provides a way to control surface oxide formation. K2(SO4)2 exhibited a shift in the O1s peak indicating the formation of a gallium-rich GaOx at the surface with decreased carbon contaminants. GaO x acts as a passivating layer prior to dielectric deposition, which resulted in an order of magnitude reduction in leakage current, a reduced hysteresis window, and an overall improvement in device performance. Furthermore, K2(SO4)2 resulted in an additional 0.4 eV of

  12. Ion exchange separation of plutonium and gallium (1) resource and inventory requirements, (2) waste, emissions, and effluent, and (3) facility size

    International Nuclear Information System (INIS)

    DeMuth, S.

    1997-01-01

    The following report summarizes an effort intended to estimate within an order-of-magnitude the (1) resource and inventory requirements, (2) waste, emissions, and effluent amounts, and (3) facility size, for ion exchange (IX) separation of plutonium and gallium. This analysis is based upon processing 3.5 MT-Pu/yr. The technical basis for this summary is detailed in a separate document, open-quotes Preconceptual Design for Separation of Plutonium and Gallium by Ion Exchangeclose quotes. The material balances of this separate document are based strictly on stoichiometric amounts rather than details of actual operating experience, in order to avoid classification as Unclassified Controlled Nuclear Information. This approximation neglets the thermodynamics and kinetics which can significantly impact the amount of reagents required. Consequently, the material resource requirements and waste amounts presented here would normally be considered minimums for processing 3.5 MT-Pu/yr; however, the author has compared the inventory estimates presented with that of an actual operating facility and found them similar. Additionally, the facility floor space presented here is based upon actual plutonium processing systems and can be considered a nominal estimate

  13. Comparison of thallium-201 and gallium-67 scintigraphy in soft tissue and bone marrow multiple myeloma: a case report

    International Nuclear Information System (INIS)

    Roach, P.J.; Arthur, C.K.

    1997-01-01

    A 68 year old female was referred for assessment of multiple myeloma. A large myelomatous infiltrate involving the left triceps muscle showed avid uptake on both thallium-201 and gallium-67 scintigraphy. Following radiotherapy, imaging with both radiopharmaceuticals showed resolution of disease; however, tumour recurrence in the bone marrow was seen only on thallium-201 imaging. This observation suggests that while soft-tissue myleoma shows similar appearances on thallium-201 and gallium-67 scintigraphy, both at baseline and following therapy, gallium-67 may not demonstrate bone marrow infiltration which is visualized on thallium-201 imaging. Therefore, thallium-201 appears to be superior to gallium-67 in evaluation of patients with multiple myeloma when soft tissues and bone marrow are involved. 17 refs., 3 figs

  14. Direct analysis of plutonium metal for gallium, iron, and nickel by energy dispersive x-ray spectrometry

    International Nuclear Information System (INIS)

    Bramlet, H.L.; Doyle, J.H.

    1981-01-01

    An x-ray secondary target method for routine determination of gallium, iron, and nickel in plutonium metal is described that has significant advantages over wet chemical analysis. Coupons requiring minimal preparation for analysis are produced as a breakaway tab on the plutonium ingot. All three elements are determined on the same coupon. Gallium is determined using an arsenic secondary target followed by iron and nickel using a zinc target. The analysis times are 5 minutes for gallium and 15 minutes for the combined iron and nickel. The method of analysis was evaluated in the range of from 0.5 to 1.5% gallium. Iron was investigated over the range of 67 to 3000 ppM and nickel from 64 to 110 ppM

  15. Distribution of species and Ga–N bonds in silicon co-implanted with gallium and nitrogen ions

    International Nuclear Information System (INIS)

    Surodin, S. I.; Nikolitchev, D. E.; Kryukov, R. N.; Belov, A. I.; Korolev, D. S.; Mikhaylov, A. N.; Tetelbaum, D. I.

    2016-01-01

    The concentration profiles of species in silicon subjected to gallium and nitrogen co-implantation and subsequent annealing have been investigated by the method of X-ray photoelectron spectroscopy combined with the layer-by-layer ion etching of the implanted layer. It is shown that practically entire implanted gallium undergoes out-diffusion, but the preliminary implantation of nitrogen for the synthesis of a barrier SiN_x layer makes it possible to avoid the essential loss of gallium. In this case, about 14 % of implanted gallium bond to nitrogen. The obtained data are discussed from the viewpoint of the possibility of ion synthesis of GaN inclusions in silicon matrix.

  16. Distribution of species and Ga–N bonds in silicon co-implanted with gallium and nitrogen ions

    Energy Technology Data Exchange (ETDEWEB)

    Surodin, S. I., E-mail: surodin.bsn@mail.ru; Nikolitchev, D. E.; Kryukov, R. N.; Belov, A. I.; Korolev, D. S.; Mikhaylov, A. N.; Tetelbaum, D. I., E-mail: tetelbaum@phys.unn.ru [Lobachevsky University, 23 Prospekt Gagarina, Nizhny Novgorod, 603950 (Russian Federation)

    2016-06-17

    The concentration profiles of species in silicon subjected to gallium and nitrogen co-implantation and subsequent annealing have been investigated by the method of X-ray photoelectron spectroscopy combined with the layer-by-layer ion etching of the implanted layer. It is shown that practically entire implanted gallium undergoes out-diffusion, but the preliminary implantation of nitrogen for the synthesis of a barrier SiN{sub x} layer makes it possible to avoid the essential loss of gallium. In this case, about 14 % of implanted gallium bond to nitrogen. The obtained data are discussed from the viewpoint of the possibility of ion synthesis of GaN inclusions in silicon matrix.

  17. O gálio e a patologia óssea Gallium and bone pathology

    Directory of Open Access Journals (Sweden)

    Petr Melnikov

    2008-01-01

    Full Text Available PROPOSTA: Revisão de trabalhos científicos referentes à incorporação do gálio no tecido ósseo, ao mecanismo da atividade terapêutica desse elemento, bem como a formação, crescimento e solubilidade da hidroxiapatita na presença dos sais de gálio. JUSTIFICATIVA: Diferente de outras drogas que impedem a perda de cálcio, os sais de elemento traço gálio são eficazes em hipercalcemia severa. O gálio (geralmente na forma de nitrato aumenta a concentração de cálcio e fósforo no osso, influindo nos osteoclastos de maneira direta não tóxica, em doses surpreendentemente baixas. Apesar de que os detalhes do mecanismo de ação do gálio não são bem esclarecidos, está comprovado que esse mecanismo envolve a inserção do gálio na matriz de hidroxiapatita, protegendo-a contra a reabsorção e melhorando as propriedades biomecânicas do sistema esquelético. Este fármaco age também nos componentes celulares do osso, impedindo sua absorção ao diminuir a secreção ácida dos osteoclastos. São necessárias mais publicações sobre o uso do gálio no tratamento de várias doenças onde prevalece esta patologia. CONCLUSÕES: Devido as suas características interessantes e promissoras, o gálio merece ser futuramente avaliado do ponto de vista experimental e clínico, como um agente antiabsortivo em ortopedia, traumatologia e doenças relacionadas com o câncer. Maior conhecimento dos mecanismos envolvidos pode fornecer as idéias para estratégia terapêutica, com o objetivo de diminuir hipercalcemia e perda óssea. Espera-se que novos compostos do gálio sejam desenvolvidos e avaliados clinicamente.PURPOSE: To review the literature concerning the incorporation of gallium into bone tissue, mechanisms of therapeutic activity of this element, as well as the formation, growth and solubility of hydroxiapatite in the presence of gallium salts. JUSTIFICATION: In contrast to other calcium-saving drugs, salts of trace element gallium are

  18. Determination of lattice orientation in aluminium alloy grains by low energy gallium ion-channelling

    Energy Technology Data Exchange (ETDEWEB)

    Silk, Jonathan R. [Aerospace Metal Composites Ltd., RAE Road, Farnborough, GU14 6XE (United Kingdom); Dashwood, Richard J. [WMG, University of Warwick, Coventry, CV4 7AL (United Kingdom); Chater, Richard J., E-mail: r.chater@imperial.ac.u [Department of Materials, Imperial College, London SW7 2AZ (United Kingdom)

    2010-06-15

    Polished sections of a fine-grained aluminium, silicon carbide metal matrix composite (MMC) alloy were prepared by sputtering using a low energy gallium ion source and column (FIB). The MMC had been processed by high temperature extrusion. Images of the polished surface were recorded using the ion-induced secondary electron emission. The metal matrix grains were distinguished by gallium ion-channelling contrast from the silicon carbide component. The variation of the contrast from the aluminium grains with tilt angle can be recorded and used to determine lattice orientation with the contrast from the silicon carbide (SiC) component as a reference. This method is rapid and suits site-specific investigations where classical methods of sample preparation fail.

  19. Dislocation structure, aging processes and critical currents of vanadium-gallium alloys

    International Nuclear Information System (INIS)

    Pan, V.M.; Beletskii, Yu.I.; Flis, V.S.; Firstov, S.A.; Sarzhan, G.F.

    1976-04-01

    An electron microscopical investigation of the structural and phase changes in vanadium-gallium alloys was carried out in the range of concentrations corresponding to a supersaturated mixed crystal with bcc lattice during plastic deformation and annealing. The determined data were compared with the measured results of the electrophysical and superconducting properties. It was shown that the deformed and aged vanadium-gallium samples at 4.2 K could conduct a dissipation-free transport current with a density of 8 x 10 3 A/cm 2 in the transversal magnetic field of 60 kOe. Based on the experimental results of the dislocation structure, the mechanism and kinetics of the separation process, conclusions were drawn as to the character of the exceeding of the critical current density in the presence of a magnetic field in these compounds. (orig.) [de

  20. Electrodeposition of gallium and zinc onto aluminium. Influence of the electrodeposited metals on the activation process

    International Nuclear Information System (INIS)

    Flamini, D.O.; Saidman, S.B.; Bessone, J.B.

    2007-01-01

    The electrodeposition of gallium and/or zinc on aluminium, aluminium-zinc alloy and vitreous carbon electrodes in chloride solutions is analysed. The electrodissolution of the formed interfaces is also described and discussed. For this purpose, potentiodynamic and potentiostatic techniques and open circuit potential measurements were employed and surface characterisation was performed by scanning electron microscopy and energy dispersive X-ray analysis. The presence of zinc, electrodeposited from the solution or as an alloying component, facilitates gallium enrichment at the interface and improves the wetting on the aluminium oxide. These conditions ensure the formation of a surface Ga-Al amalgam. As a result, the dissolution process occurs at potentials which are more active than those observed for aluminium or aluminium-zinc alloy in halide solutions

  1. A new myocardial imaging agent: Synthesis, characterization, and biodistribution of gallium-68-BAT-TECH

    International Nuclear Information System (INIS)

    Kung, H.F.; Liu, B.L.; Mankoff, D.; Kung, M.P.; Billings, J.J.; Francesconi, L.; Alavi, A.

    1990-01-01

    In order to develop a new myocardial perfusion agent for positron emission tomography (PET), a new lipid-soluble gallium complex was evaluated. Synthesis, radiolabeling, characterization, and biodistribution of a unique gallium complex, [ 67 Ga]BAT-TECH (bis-aminoethanethiol-tetraethyl-cyclohexyl), are described. The complex formation between Ga+3 and BAT-TECH ligand is simple, rapid, and of high yield (greater than or equal to 95%). This process is amenable to kit formulation. The complex has a net charge of +1 and a Ga/ligand ratio of 1:1. Biodistribution in rats shows high uptake in the heart as well as in the liver. When [ 68 Ga] BAT-TECH was injected into a monkey, the heart and liver are clearly delineated by PET imaging, suggesting that this complex may be a possible tracer for myocardial perfusion imaging

  2. Extraction of aluminium, gallium and indium by tri-n-octylamine from citric acid solutions

    International Nuclear Information System (INIS)

    Bol'shova, T.A.; Kaplunova, A.M.; Ershova, N.I.; Varshal, E.B.

    1984-01-01

    A study was made on aluminium, gallium and indium distribution in triocylam ine(toa)-citric acid system depending on pH of aqueous solution, concentration of components and foreign electrolytes. The methods of equilibrium shift, compe ting ions and isomolar series were used to find the component ratio in toa: Me: citric acid complexes equal to 3:1:2. The equation describing the extraction of citrate gallium, indium and aluminium complexes by trioctylamine was suggested. Using the difference in extraction behavior of the elements of aluminium, yttri um and lanthanum subgroup the extraction-chromatographic method of their separat ion, applied for the analysis of optical glasses was developed. The method is c haracterized by satisfactory reproduction, simplicity and expre

  3. Electrodeposition of gallium and zinc onto aluminium. Influence of the electrodeposited metals on the activation process

    Energy Technology Data Exchange (ETDEWEB)

    Flamini, D.O. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Departamento de Ingenieria Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina); Saidman, S.B. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Departamento de Ingenieria Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina)], E-mail: ssaidman@criba.edu.ar; Bessone, J.B. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Departamento de Ingenieria Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina)

    2007-07-31

    The electrodeposition of gallium and/or zinc on aluminium, aluminium-zinc alloy and vitreous carbon electrodes in chloride solutions is analysed. The electrodissolution of the formed interfaces is also described and discussed. For this purpose, potentiodynamic and potentiostatic techniques and open circuit potential measurements were employed and surface characterisation was performed by scanning electron microscopy and energy dispersive X-ray analysis. The presence of zinc, electrodeposited from the solution or as an alloying component, facilitates gallium enrichment at the interface and improves the wetting on the aluminium oxide. These conditions ensure the formation of a surface Ga-Al amalgam. As a result, the dissolution process occurs at potentials which are more active than those observed for aluminium or aluminium-zinc alloy in halide solutions.

  4. Separation of gallium and actinides in plutonium nuclear materials by extraction chromatography

    International Nuclear Information System (INIS)

    Eitrheim, E.S.; Knight, A.W.

    2015-01-01

    Analysis of stable gallium in nuclear materials has applications in nuclear fuel characterization and nuclear forensics. The use of positron-emitting gallium isotope 68 Ga as a tracer for Ga recoveries for analyses in materials containing actinides was explored. A radiochemical method for the separation of Ga, Pu, U, Th, and Am using commercially-available extraction chromatography resins was developed and evaluated. The method effectively allows precise determination of Ga yield (97 ± 3 %) in the analysis of stable Ga (spike recovery 101 ± 1 %) and radioactive Pu (radiochemical yield, 82 ± 10 %; spike recovery, 96 ± 3 %), while also providing pure elemental fractions of other actinides relevant to materials encountered in the analysis Pu-containing materials. (author)

  5. Chemical composition of cadmium selenochromite crystals doped with indium, silver and gallium

    International Nuclear Information System (INIS)

    Bel'skij, N.K.; Ochertyanova, L.I.; Shabunina, G.G.; Aminov, T.G.

    1985-01-01

    The high accuracy chemical analysis Which allows one to observe doping effect on the cadmium selenochromite crystal composition is performed. The problem on the possibility of impurity atom substitution for basic element is considered on the basis of data of atomic-absorption analysis of doped crystals. The crystals of cadmium selenochromite doped with indium by chromium to cadmium ratio are distributed into two groups and probably two types of substitution take place. At 0.08-1.5 at.% indium concentrations the Cr/Cd ratio >2. One can assume that indium preferably takes cadmium tetrahedral positions whereas at 1.5-2.5 at. % concentrations the Cr/Cd ratio =2 and cadmium is substituted for silver which does not contradict crystallochemical and physical properties of this compound. In crystals with gallium the Cr/Cd ratio <2. Gallium preferably substitutes chromium

  6. Hodgkin`s disease: internal mammary lymph nodes relapse diagnosed by Gallium-67 scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Hernandez, G.; Ampudia, J.; Castillo, F.J.; Romero, C. [Hospital Clinico Univ., Valencia (Spain). Servicio de Medicina Nuclear; Pallardo, Y. [Hospital Clinico Univ., Valencia (Spain). Servicio de Radiologia; Garcia Conde, J. [Hospital Clinico Univ., Valencia (Spain). Servicio de Hematologia y Oncologia Medica; Ramos, D. [Hospital Clinico Univ., Valencia (Spain). Servicio de Anatomia Patologica

    1999-04-01

    This article presents the case of a 62-year-old man with treated Hodgkin`s disease who had internal mammary lymph nodes relapse after a complete initial response. These masses were gallium avid. These findings were explained by histologically documented Hodgkin`s relapse, the first such case reported in that localization without chest wall involvement. The literature on mediastinal Hodgkin`s disease and diagnostic procedures are reviewed. (orig.) [Deutsch] Beschrieben wird der Fall eines 62jaehrigen Mannes, der nach initial erfolgreicher Therapie eines Morbus Hodgkin ein Lymphknotenrezidiv im Bereich der Brust aufweist. Die Lymphknoten reicherten Gallium an. Histologisch wurde das Hodgkinrezidiv gesichert. Es handelt sich um den ersten in diesem Bereich beschriebenen Fall ohne Infiltration der Brustwand. Die Literatur ueber mediastinalen Morbus Hodgkin und diagnostisches Vorgehen wurde ueberprueft. (orig.)

  7. Angular and mass resolved energy distribution measurements with a gallium liquid metal ion source

    International Nuclear Information System (INIS)

    Marriott, Philip

    1987-06-01

    Ionisation and energy broadening mechanisms relevant to liquid metal ion sources are discussed. A review of experimental results giving a picture of source operation and a discussion of the emission mechanisms thought to occur for the ionic species and droplets emitted is presented. Further work is suggested by this review and an analysis system for angular and mass resolved energy distribution measurements of liquid metal ion source beams has been constructed. The energy analyser has been calibrated and a series of measurements, both on and off the beam axis, of 69 Ga + , Ga ++ and Ga 2 + ions emitted at various currents from a gallium source has been performed. A comparison is made between these results and published work where possible, and the results are discussed with the aim of determining the emission and energy spread mechanisms operating in the gallium liquid metal ion source. (author)

  8. Magnetic refrigeration cycle analysis using selected thermodynamic property characterizations for gadolinium gallium garnet

    International Nuclear Information System (INIS)

    Murphy, R.W.

    1992-01-01

    Magneto-thermodynamic property characterizations were selected, adapted, and compared to material property data for gadolinium gallium garnet in the temperature range 4--40 K and magnetic field range 0--6 T. The most appropriate formulations were incorporated into a model in which methods similar to those previously developed for other materials and temperature ranges were used to make limitation and relative performance assessments of Carnot, ideal regenerative, and pseudo-constant field regenerative cycles. Analysis showed that although Carnot cycle limitations on available temperature lift for gadolinium gallium garnet are not as severe as those for materials previously examined, substantial improvements in cooling capacity/temperature lift combinations can be achieved using regenerative cycles within specified fields limits if significant loss mechanisms are mitigated

  9. Adsorption configuration of magnesium on wurtzite gallium nitride surface using first-principles calculations

    International Nuclear Information System (INIS)

    Yan Han; Gan Zhiyin; Song Xiaohui; Chen Zhaohui; Xu Jingping; Liu Sheng

    2009-01-01

    First-principles calculations of magnesium adsorption at the Ga-terminated and N-terminated {0 0 0 1} basal plane wurtzite gallium nitride surfaces have been carried out to explain the atomic-scale insight into the initial adsorption processes of magnesium doping in gallium nitride. The results reveal that magnesium adsorption on N-terminated surfaces is preferred than that on Ga-terminated surfaces. Furthermore, the surface diffusivity of magnesium atom on the N-terminated surface is much lower than that on the Ga-terminated surface, which is due to both the larger average adsorption energies and the lower adsorption distance on N-terminated surface than that on Ga-terminated surface. The results indicate that the p-type doping on the Ga-terminated surface will be better distributed than that on the N-terminated surface.

  10. The fabrication of silicon nanostructures by local gallium implantation and cryogenic deep reactive ion etching

    International Nuclear Information System (INIS)

    Chekurov, N; Grigoras, K; Franssila, S; Tittonen, I; Peltonen, A

    2009-01-01

    We show that gallium-ion-implanted silicon serves as an etch mask for fabrication of high aspect ratio nanostructures by cryogenic plasma etching (deep reactive ion etching). The speed of focused ion beam (FIB) patterning is greatly enhanced by the fact that only a thin approx. 30 nm surface layer needs to be modified to create a mask for the etching step. Etch selectivity between gallium-doped and undoped material is at least 1000:1, greatly decreasing the mask erosion problems. The resolution of the combined FIB-DRIE process is 20 lines μm -1 with the smallest masked feature size of 40 nm. The maximum achieved aspect ratio is 15:1 (e.g. 600 nm high pillars 40 nm in diameter).

  11. Effect of pressure on some physical properties of gallium based semiconductors

    International Nuclear Information System (INIS)

    Vyas, P S; Thakore, B Y; Jani, A R; Gajjar, P N

    2012-01-01

    The gallium based semiconductor compounds are very useful materials for optical spectroscopy and optoelectronic applications, we have studied the effect of pressure on various physical properties like total energy, static bulk modulus, energy band gap at the point X on the Jones-zone face, pressure derivative of bulk modulus and equation of state of gallium based binary compounds GaSb, GaAs, GaP and GaN using pseudopotential theory beyond second order with our well established single parametric model potential. We have incorporated Nagy's static local field correction function to include exchange and correlation effects. The results are compared with those obtained using few other local field correction functions. The present results agree satisfactorily with available experimental and other such theoretical data confirming the application.

  12. Osteomyelitis and infarction in sickle cell hemoglobinopathies: differentiation by combined technetium and gallium scintigraphy

    International Nuclear Information System (INIS)

    Amundsen, T.R.; Siegel, M.J.; Siegel, B.A.

    1984-01-01

    Clinical records and scintigrams were reviewed of 18 patients with sickle cell hemoglobinophaties who had undergone combined technetium and gallium scintigraphy during 22 separate episodes of suspected osseous infection. The combined scintigrams were correctly interpreted as indicating osteomyelitis in four studies. Of 18 studies in patients with infarction, the combined scintigrams were correctly interpreted in 16 and showed either no local accumulation of Ga-67 or less accumulation than that of Tc-99m MDP at symptomatic sites. In the other two studies, the scintigrams were falsely interpreted as indicating osteomyelitis and showed congruent, increased accumulation of both Tc-99, MDP and Ga-67. This pattern must be considered indeterminate. Overall, the results indicate that the combination of technetium and gallium scintigraphy is an effective means to distinguish osteomyelitis from infarction in patients with sickle cell hemoglobinopathies

  13. Gallium sorption on montmorillonite and illite colloids: Experimental study and modelling by ionic exchange and surface complexation

    International Nuclear Information System (INIS)

    Benedicto, Ana; Degueldre, Claude; Missana, Tiziana

    2014-01-01

    Highlights: • Ga sorption onto illite and montmorillonite was studied and modelled for the first time. • The developed sorption model was able to well explain Ga sorption in both clays. • Number of free parameters was reduced applying the linear free energy relationship. • Cationic exchange dominate sorption at pH < 4.5; surface complexation at higher pH. - Abstract: The migration of metals as gallium (Ga) in the environment is highly influenced by their sorption on clay minerals, as montmorillonite and illite. Given the increased usage of gallium in the industry and the medicine, the Ga-associated waste may result in environmental problems. Ga sorption experiments were carried out on montmorillonite and illite colloids in a wide range of pH, ionic strength and Ga concentration. A Ga sorption model was developed combining ionic exchange and surface complexation on the edge sites (silanol and aluminol-like) of the clay sheets. The complexation constants were estimated as far as possible from the Ga hydrolysis constants applying the linear free energy relationship (LFER), which allowed to reduce the number of free parameters in the model. The Ga sorption behaviour was very similar on illite and montmorillonite: decreasing tendency with pH and dependency on ionic strength at very acidic conditions. The experimental data modelling suggests that the Ga sorption reactions avoid the Ga precipitation, which is predicted in absence of clay colloids between pH 3.5 and 5.5. Assuming this hypothesis, clay colloids would affect Ga aqueous speciation, preventing precipitation in favour of sorption. Ga sorption on montmorillonite and illite can be explained on the basis of three main reactions: Ga 3+ exchange at very acidic conditions (pH < ∼3.8); Ga(OH) 4 - complexation on protonated weak sites in acidic-neutral conditions (between pH ∼5.2 and pH ∼7.9); and Ga(OH) 3 complexation on strong sites at basic conditions (pH > ∼7.9)

  14. Synthesis, Characterization, and Processing of Copper, Indium, and Gallium Dithiocarbamates for Energy Conversion Applications

    Science.gov (United States)

    Duraj, S. A.; Duffy, N. V.; Hepp, A. F.; Cowen, J. E.; Hoops, M. D.; Brothrs, S. M.; Baird, M. J.; Fanwick, P. E.; Harris, J. D.; Jin, M. H.-C.

    2009-01-01

    Ten dithiocarbamate complexes of indium(III) and gallium(III) have been prepared and characterized by elemental analysis, infrared spectra and melting point. Each complex was decomposed thermally and its decomposition products separated and identified with the combination of gas chromatography/mass spectrometry. Their potential utility as photovoltaic materials precursors was assessed. Bis(dibenzyldithiocarbamato)- and bis(diethyldithiocarbamato)copper(II), Cu(S2CN(CH2C6H5)2)2 and Cu(S2CN(C2H5)2)2 respectively, have also been examined for their suitability as precursors for copper sulfides for the fabrication of photovoltaic materials. Each complex was decomposed thermally and the products analyzed by GC/MS, TGA and FTIR. The dibenzyl derivative complex decomposed at a lower temperature (225-320 C) to yield CuS as the product. The diethyl derivative complex decomposed at a higher temperature (260-325 C) to yield Cu2S. No Cu containing fragments were noted in the mass spectra. Unusual recombination fragments were observed in the mass spectra of the diethyl derivative. Tris(bis(phenylmethyl)carbamodithioato-S,S'), commonly referred to as tris(N,N-dibenzyldithiocarbamato)indium(III), In(S2CNBz2)3, was synthesized and characterized by single crystal X-ray crystallography. The compound crystallizes in the triclinic space group P1(bar) with two molecules per unit cell. The material was further characterized using a novel analytical system employing the combined powers of thermogravimetric analysis, gas chromatography/mass spectrometry, and Fourier transform infrared (FT-IR) spectroscopy to investigate its potential use as a precursor for the chemical vapor deposition (CVD) of thin film materials for photovoltaic applications. Upon heating, the material thermally decomposes to release CS2 and benzyl moieties in to the gas phase, resulting in bulk In2S3. Preliminary spray CVD experiments indicate that In(S2CNBz2)3 decomposed on a Cu substrate reacts to produce

  15. Proton Irradiation-Induced Metal Voids in Gallium Nitride High Electron Mobility Transistors

    Science.gov (United States)

    2015-09-01

    ABBREVIATIONS 2DEG two-dimensional electron gas AlGaN aluminum gallium nitride AlOx aluminum oxide CCD charged coupled device CTE coefficient of...frequency of FETs. Such a device may also be known as a heterojunction field-effect transistor (HFET), modulation-doped field-effect transistor (MODFET...electrons. This charge attracts electrons to the interface, forming the 2DEG channel. The HEMT includes a heterojunction of two semiconducting

  16. Surface Passivation for 3-5 Semiconductor Processing: Stable Gallium Sulphide Films by MOCVD

    Science.gov (United States)

    Macinnes, Andrew N.; Jenkins, Phillip P.; Power, Michael B.; Kang, Soon; Barron, Andrew R.; Hepp, Aloysius F.; Tabib-Azar, Massood

    1994-01-01

    Gallium sulphide (GaS) has been deposited on GaAs to form stable, insulating, passivating layers. Spectrally resolved photoluminescence and surface recombination velocity measurements indicate that the GaS itself can contribute a significant fraction of the photoluminescence in GaS/GaAs structures. Determination of surface recombination velocity by photoluminescence is therefore difficult. By using C-V analysis of metal-insulator-semiconductor structures, passivation of the GaAs with GaS films is quantified.

  17. Hodgkin's disease: internal mammary lymph nodes relapse diagnosed by Gallium-67 scintigraphy

    International Nuclear Information System (INIS)

    Ruiz Hernandez, G.; Ampudia, J.; Castillo, F.J.; Romero, C.; Pallardo, Y.; Garcia Conde, J.; Ramos, D.

    1999-01-01

    This article presents the case of a 62-year-old man with treated Hodgkin's disease who had internal mammary lymph nodes relapse after a complete initial response. These masses were gallium avid. These findings were explained by histologically documented Hodgkin's relapse, the first such case reported in that localization without chest wall involvement. The literature on mediastinal Hodgkin's disease and diagnostic procedures are reviewed. (orig.) [de

  18. Point defects in gallium arsenide characterized by positron annihilation spectroscopy and deep level transient spectroscopy

    International Nuclear Information System (INIS)

    Mih, R.; Gronsky, R.; Sterne, P.A.

    1995-01-01

    Positron annihilation lifetime spectroscopy (PALS) is a unique technique for detection of vacancy related defects in both as-grown and irradiated materials. The authors present a systematic study of vacancy defects in stoichiometrically controlled p-type Gallium Arsenide grown by the Hot-Wall Czochralski method. Microstructural information based on PALS, was correlated to crystallographic data and electrical measurements. Vacancies were detected and compared to electrical levels detected by deep level transient spectroscopy and stoichiometry based on crystallographic data

  19. Impurity decoration of native vacancies in Ga and N sublattices of gallium nitride

    OpenAIRE

    Hautakangas, Sami

    2005-01-01

    The effects of impurity atoms as well as various growth methods to the formation of vacancy type defects in gallium nitride (GaN) have been studied by positron annihilation spectroscopy. It is shown that vacancy defects are formed in Ga or N sublattices depending on the doping of the material. Vacancies are decorated with impurity atoms leading to the compensation of the free carriers of the samples. In addition, the vacancy clusters are found to be present in significant concentrations in n-...

  20. Dissolution rates and solubility of some metals in liquid gallium and aluminum

    International Nuclear Information System (INIS)

    Yatsenko, S P; Sabirzyanov, N A; Yatsenko, A S

    2008-01-01

    The effect of liquid gallium and aluminum on some hard metals leading to dissolution and formation of intermetallic compounds (IMC) under static conditions and rotation of a specimen is studied. The solubility parameters from the Clapeyron-Clausius equation were considered to estimate the stability of still not studied metals. The presented experimental data on solubility and corrosion in a wide temperature range allow to calculate a number of parameters useful in manufacturing and application of master-alloys

  1. The Effects of Thermal Cycling on Gallium Nitride and Silicon Carbide Semiconductor Devices for Aerospace Use

    Science.gov (United States)

    Patterson, Richard L.; Hammoud, Ahmad

    2012-01-01

    Electronics designed for use in NASA space missions are required to work efficiently and reliably under harsh environment conditions. These Include radiation, extreme temperatures, thermal cycling, to name a few. Preliminary data obtained on new Gallium Nitride and Silicon Carbide power devices under exposure to radiation followed by long term thermal cycling are presented. This work was done in collaboration with GSFC and JPL in support of the NASA Electronic Parts and Packaging (NEPP) Program

  2. Gallium SPECT detection of neoplastic intravascular obstruction of the superior vena cava

    International Nuclear Information System (INIS)

    Swayne, L.C.; Kaplan, I.L.

    1989-01-01

    A rare case of an intravascular neoplastic obstruction of the superior vena cava is discussed. The lesion was detected with gallium single photon emission computed tomography (SPECT) despite a normal appearance on a concurrent radiographic CT study. A computer-generated composite SPECT-CT image confirmed the intravascular localization of the radioisotope, and a subsequent CT-guided transthoracic needle biopsy revealed a poorly differentiated adenocarcinoma

  3. On the photon annealing of silicon-implanted gallium-nitride layers

    International Nuclear Information System (INIS)

    Seleznev, B. I.; Moskalev, G. Ya.; Fedorov, D. G.

    2016-01-01

    The conditions for the formation of ion-doped layers in gallium nitride upon the incorporation of silicon ions followed by photon annealing in the presence of silicon dioxide and nitride coatings are analyzed. The conditions of the formation of ion-doped layers with a high degree of impurity activation are established. The temperature dependences of the surface concentration and mobility of charge carriers in ion-doped GaN layers annealed at different temperatures are studied.

  4. Conversion of n-Butane to iso-Butene on Gallium/HZSM-5 Catalysts

    Directory of Open Access Journals (Sweden)

    S.M. Gheno

    2002-07-01

    Full Text Available The conversion of n-butane to iso-butene on gallium/HZSM-5 catalysts at 350ºC and WHSV=2.5h8-1 was studied. The catalysts were prepared by ion exchange from a Ga(NO32 solution and further submitted to calcination in air at 530ºC. TEM analysis with an EDAX detector and TPR-H2 data showed that after calcination the Ga species were present mainly as Ga2O3, which are reduced to Ga2O at temperatures near 610ºC. The specific acid activity (SAA of the catalysts increased with the increase in aluminum content in the zeolite, and for a fixed Si/Al ratio, the SAA increased with Ga content. Values for specific hydro/dehydrogenation activity (SH/DHA were significantly higher than those for SAA, indicating that the catalytic process is controlled by the kinetics on acid sites. Moreover, the production of iso-butene with a selectivity higher than 25% was a evidence that in gallium/HZSM-5-based catalysts the rate of the hydrogenation reaction is lower than that of the dehydrogenation reaction; this behavior confirmed the dehydrogenation nature of gallium species, thereby showing great promise for iso-butene production.

  5. Ingestion of gallium phosphide nanowires has no adverse effect on Drosophila tissue function

    International Nuclear Information System (INIS)

    Adolfsson, Karl; Hammarin, Greger; Prinz, Christelle N; Schneider, Martina; Häcker, Udo

    2013-01-01

    Engineered nanoparticles have been under increasing scrutiny in recent years. High aspect ratio nanoparticles such as carbon nanotubes and nanowires have raised safety concerns due to their geometrical similarity to asbestos fibers. III–V epitaxial semiconductor nanowires are expected to be utilized in devices such as LEDs and solar cells and will thus be available to the public. In addition, clean-room staff fabricating and characterizing the nanowires are at risk of exposure, emphasizing the importance of investigating their possible toxicity. Here we investigated the effects of gallium phosphide nanowires on the fruit fly Drosophila melanogaster. Drosophila larvae and/or adults were exposed to gallium phosphide nanowires by ingestion with food. The toxicity and tissue interaction of the nanowires was evaluated by investigating tissue distribution, activation of immune response, genome-wide gene expression, life span, fecundity and somatic mutation rates. Our results show that gallium phosphide nanowires applied through the diet are not taken up into Drosophila tissues, do not elicit a measurable immune response or changes in genome-wide gene expression and do not significantly affect life span or somatic mutation rate. (paper)

  6. Gallium-67 imaging in human heart transplantation: correlation with endomyocardial biopsy

    International Nuclear Information System (INIS)

    Meneguetti, J.C.; Camargo, E.E.; Soares, J. Jr.

    1987-01-01

    Endomyocardial biopsy seems to be the most accurate method to use for diagnosis and follow-up of acute rejection of the transplanted heart. This investigation compared a noninvasive procedure, gallium-67 imaging, with endomyocardial biopsy in the detection of acute rejection in heart transplantation. Seven male patients (aged 41 to 54 years) sequentially had 46 gallium-67 scintigrams and 46 endomyocardial biopsies between 1 week and 8 months after transplantation. Both studies were obtained in the same day, 48 hours after the administration of an intravenous injection of gallium-67 citrate. Cardiac uptake was graded as negative, mild, moderate, and marked according to an increasing count ratio with rib and sternal uptakes. Histologic findings were graded as negative, mild acute rejection, moderate acute rejection, severe acute rejection, resolving rejection, and nonspecific reaction. Negative biopsies were not found with moderate uptake, and neither moderate nor severe acute rejection were found with negative scintigrams. Imaging sensitivity was 83% with 17% false negatives and 9% false positives. Of seven studies with moderate uptake, five showed moderate acute rejection, and the patients had specific therapy with a decline in uptake, which correlated with resolving rejection. It is conceivable that in the future this technique may be used as a screening procedure for sequential endomyocardial biopsies in the follow-up of heart transplant patients

  7. Discriminating a deep defect from shallow acceptors in supercell calculations: gallium antisite in GaAs

    Science.gov (United States)

    Schultz, Peter

    To make reliable first principles predictions of defect energies in semiconductors, it is crucial to discriminate between effective-mass-like defects--for which existing supercell methods fail--and deep defects--for which density functional theory calculations can yield reliable predictions of defect energy levels. The gallium antisite GaAs is often associated with the 78/203 meV shallow double acceptor in Ga-rich gallium arsenide. Within a framework of level occupation patterns, analyses of structure and spin stabilization can be used within a supercell approach to distinguish localized deep defect states from shallow acceptors such as BAs. This systematic analysis determines that the gallium antisite is inconsistent with a shallow state, and cannot be the 78/203 shallow double acceptor. The properties of the Ga antisite in GaAs are described, predicting that the Ga antisite is a deep double acceptor and has two donor states, one of which might be accidentally shallow. -- Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  8. Increased bone marrow uptake of gallium-67 in patients with fever of unknown origin

    International Nuclear Information System (INIS)

    Flores, L.G.; Jinnouchi, S.; Nagamachi, S.; Ohnishi, T.; Futami, S.; Watanabe, K.

    1996-01-01

    Purpose of the study: we studied the relationships of clinical diagnosis, the effect of blood chemistry and the clinical implication of increased gallium-67 in the bone marrow of patients presenting signs and symptoms of FUO. Materials and Methods: Based on intensity of gallium-67 uptake in bone marrow, patients were classified as follows: Type 1 when there is no evidence or very faint bone marrow uptake in vertebrae, Type 2 when mild to moderate, Type 3 when uptake is severe. The relationships of white blood cell count (WBC), hemoglobin concentration, hematocrit count, serum iron and unsaturated iron biding capacity (UIBC) with the occurrence of increased bone marrow uptake in the different groups were noted. Analysis of variance with Fishers Protected Least Significant Difference was used. A.p. value less than 0.05 was considered significant. Results: The results showed significant differences between Types 1 and 2 and between Type 1 and 3 for WBC counts, serum hemoglobin and serum hematocrit level. Serum iron concentration and UIBC however, did not show any significant differences. Conclusion: Significant changes in WBC count, Hb concentration and Hct count in FUO patients were accompanied by varying intensity of gallium-67 uptake in the bone marrow. (author)

  9. Gallium hole traps in irradiated KTiOPO{sub 4}:Ga crystals

    Energy Technology Data Exchange (ETDEWEB)

    Grachev, V.; Meyer, M.; Malovichko, G. [Physics Department, Montana State University, Bozeman, Montana 59717 (United States); Hunt, A. W. [Idaho Accelerator Center, Idaho State University, Pocatello, Idaho 83209 (United States)

    2014-12-07

    Nominally pure and gallium doped single crystals of potassium titanyl phosphate (KTiOPO{sub 4}) have been studied by Electron Paramagnetic Resonance at low temperatures before and after irradiation. Irradiation with 20 MeV electrons performed at room temperature and liquid nitrogen temperature caused an appearance of electrons and holes. Gallium impurities act as hole traps in KTiOPO{sub 4} creating Ga{sup 4+} centers. Two different Ga{sup 4+} centers were observed, Ga1 and Ga2. The Ga1 centers are dominant in Ga-doped samples. For the Ga1 center, a superhyperfine structure with one nucleus with nuclear spin ½ was registered and attributed to the interaction of gallium electrons with a phosphorus nucleus or proton in its surrounding. In both Ga1 and Ga2 centers, Ga{sup 4+} ions substitute for Ti{sup 4+} ions, but with a preference to one of two electrically distinct crystallographic positions (site selective substitution). The Ga doping eliminates one of the shortcomings of KTP crystals—ionic conductivity of bulk crystals. However, this does not improve significantly the resistance of the crystals to electron and γ-radiation.

  10. New techniques of laser spectroscopy on exotic isotopes of gallium and francium

    CERN Document Server

    Procter, Thomas John

    The neutron-deficient gallium isotopes down to ${N}$=32 have had their hyperfine structures and isotope shifts measured via collinear laser spectroscopy using the COLLAPS (COllinear LAser sPectroScopy) beam line. The ground-state spin of $^{63}$Ga has been determined as ${I}$ = 3/2 and its magnetic dipole and electric quadrupole moments were measured to be $\\mu$ = +1.469(5) $_{\\mu N}$ and ${ Q}$s = +0.212(14) b respectively. The nuclear moments of $^{70}$Ga were measured to be ${\\mu}$= +0.571(2) $_{\\mu}$ and ${Q}$s = +0.105(7) b. New isotope shift results were combined with previously measured values of the neutron-rich isotopes and the changes in mean-square charge radii of the entire gallium isotope chain were investigated. Analysis of the trend in the neutron-deficient charge radii demonstrated that there is no evidence of anomalous charge radii behaviour in gallium in the region of ${N}$=32. A sudden increase of the charge radii was observed at the ${N}$=50 shell gap and an inversion of the normal odd-eve...

  11. Highly-Bioreactive Silica-Based Mesoporous Bioactive Glasses Enriched with Gallium(III

    Directory of Open Access Journals (Sweden)

    Sandra Sanchez-Salcedo

    2018-03-01

    Full Text Available Beneficial effects in bone cell growth and antibacterial action are currently attributed to Ga3+ ions. Thus, they can be used to upgrade mesoporous bioactive glasses (MBGs, investigated for tissue engineering, whenever they released therapeutic amounts of gallium ions to the surrounding medium. Three gallium-enriched MBGs with composition (in mol % xSiO2–yCaO–zP2O5–5Ga2O3, being x = 70, y = 15, z = 10 for Ga_1; x = 80, y = 12, z = 3 for Ga_2; and x = 80, y = 15, z = 0 for Ga_3, were investigated and compared with the gallium-free 80SiO2–15CaO–5P2O5 MBG (B. 29Si and 31P MAS NMR analyses indicated that Ga3+ acts as network modifier in the glass regions with higher polymerization degree and as network former in the zones with high concentration of classical modifiers (Ca2+ ions. Ga_1 and Ga_2 exhibited a quick in vitro bioactive response because they were coated by an apatite-like layer after 1 and 3 days in simulated body fluid. Although we have not conducted biological tests in this paper (cells or bacteria, Ga_1 released high but non-cytotoxic amounts of Ga3+ ions in Todd Hewitt Broth culture medium that were 140 times higher than the IC90 of Pseudomonas aeruginosa bacteria, demonstrating its potential for tissue engineering applications.

  12. The role of gallium-67 tumour scintigraphy in patients with small, non-cleaved cell lymphoma

    International Nuclear Information System (INIS)

    Sandrock, D.; Lastoria, S.; Neumann, R.D.; Magrath, I.T.

    1993-01-01

    Two hundred and thirty-four scintigraphic studies were performed in 34 patients (27 men, 7 women, age 17.3±7.7 years) with small, non-cleaved cell lymphoma who had follow-up for 3-96 months (mean 21.6±21.7 months). Whole-body scintigraphy was performed 48-72 h following i.v. injection of 370 MBq gallium-67 citrate. 'Gold standards' for truth determinations were surgery, autopsy, histology, axial X-ray computed tomography, magnetic resonance imaging, ultrasonography and clinical follow-up. Overall, 181 of 234 studies were true negative. Eighty proven sites of disease had true positive 67 Ga uptake (in 21 patients/37 studies). Nineteen sites (in 12 patients/15 studies) were false positive. In addition, 31 benign lesions were detected and interpreted correctly in terms of non-malignancy. Ten lymphoma sites (in 6 patients/10 studies) were missed by scintigraphy. Overall, sensitivity of gallium scintigraphy was 89% when calculated by sites and 79% when calculated by studies. Corresponding specificities were 91% and 92%, respectively. Positive predictive values were 81% (sites) and 71% (studies), and negative predictive values 95% (sites and studies). Thus, gallium scintigraphy proved to be a sensitive and specific method for staging and follow-up in patients with small, non-cleaved cell lymphoma. (orig.)

  13. Glycosaminoglycan, computed tomography and gallium-67 scanning in malignant pleural mesothelioma

    International Nuclear Information System (INIS)

    Nakano, Takashi; Fujii, Junji; Yamakawa, Kiyohiro; Tamura, Shinsuke; Amuro, Yoshiki; Nabeshima, Kenji; Hada, Toshikazu; Higashino, Kazuya; Horai, Takeshi.

    1985-01-01

    Malignant pleural mesothelioma is an unusual disease, often difficult to diagnose. This paper describes the results of quantitative studies on glycosaminoglycan (GAG) in tumor tissues and the findings of chest computed tomography (CT) and gallium-67 scanning in 5 malignant pleural mesotheliomas. The total amount of GAG in tumor tissue was 2.3 to 17.0 times as high as that in adenocarcinoma of the lung. The amount of hyaluronic acid was 3.5 to 170 times higher than that in adenocarcinoma. Also, the amount of chondroitin sulfate increased 2.6 to 10.0 times, but there were no changes in dermatan sulfate and heparan sulfate contents in this neoplasm when compared with adenocarcinoma. The present study suggests that a marked increase of the total amount of GAG and elevation of either hyaluronic acid and chondroitin sulfate content or both is a characteristic abnormality in this neoplasm. In most cases, CT scan of the chest showed pleural effusion, irregular pleural tumorous thickening surrounding the whole lung surface and extension into the fissure. In 3 cases, tumorous lesions extending into the chest wall at the site of pleural biopsy could be visualized on CT. In the terminal stage, the thoracic cavity was occupied by tumor tissues. Gallium-67 scanning showed a diffusely increased radionuclide accumulation over the involved hemithorax with or without particular intensity in the periphery. Conversely, identification of these characteristic findings of CT and gallium-67 scanning indicates the possibility of malignant pleural mesothelioma. (author)

  14. Channel length dependence of negative-bias-illumination-stress in amorphous-indium-gallium-zinc-oxide thin-film transistors

    Energy Technology Data Exchange (ETDEWEB)

    Um, Jae Gwang; Mativenga, Mallory; Jang, Jin, E-mail: jjang@khu.ac.kr [Advanced Display Research Center, Department of Information Display, Kyung Hee University, Dongdaemun-gu, Seoul 130-701 (Korea, Republic of); Migliorato, Piero [Advanced Display Research Center, Department of Information Display, Kyung Hee University, Dongdaemun-gu, Seoul 130-701 (Korea, Republic of); Electrical Engineering Division, Department of Engineering, Cambridge University, Cambridge CB3 0FA (United Kingdom)

    2015-06-21

    We have investigated the dependence of Negative-Bias-illumination-Stress (NBIS) upon channel length, in amorphous-indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs). The negative shift of the transfer characteristic associated with NBIS decreases for increasing channel length and is practically suppressed in devices with L = 100-μm. The effect is consistent with creation of donor defects, mainly in the channel regions adjacent to source and drain contacts. Excellent agreement with experiment has been obtained by an analytical treatment, approximating the distribution of donors in the active layer by a double exponential with characteristic length L{sub D} ∼ L{sub n} ∼ 10-μm, the latter being the electron diffusion length. The model also shows that a device with a non-uniform doping distribution along the active layer is in all equivalent, at low drain voltages, to a device with the same doping averaged over the active layer length. These results highlight a new aspect of the NBIS mechanism, that is, the dependence of the effect upon the relative magnitude of photogenerated holes and electrons, which is controlled by the device potential/band profile. They may also provide the basis for device design solutions to minimize NBIS.

  15. Implication of gallium results on the possibility of observing day-night matter oscillations at SNO, Super-Kamiokande, and Borexino

    International Nuclear Information System (INIS)

    Baltz, A.J.; Weneser, J.

    1994-01-01

    Calculations are presented to determine what real time day-night effects would be observable at SNO, Super-Kamiokande, or Borexino for the Δm 2 , sin 2 2θ space allowed by the present gallium, 37 Cl, and Kamiokande solar neutrino results. We show that the combination of possible day-night effects and the observation of overall neutrino detection rates in the upcoming experiments might allow discrimination between the allowed regions of mass and mixing parameters. Approximate analytical expressions for the real time MSW effect in the Earth are presented to clarify the nature of electron-neutrino regeneration as a function of path length through the Earth. We point out that even for the allowed small sin 2 2θ MSW solution, it might be possible to detect a day-night effect for neutrino trajectories through the core of the Earth

  16. GALAXI: Gallium anode low-angle x-ray instrument

    Directory of Open Access Journals (Sweden)

    Emmanuel Kentzinger

    2016-03-01

    Full Text Available The high brilliance laboratory small angle X-ray scattering instrument GALAXI, which is operated by JCNS, Forschungszentrum Jülich, permits the investigation of chemical correlations in bulk materials or of structures deposited on a surface at nanometre and mesoscopic length scales. The instrument is capable to perform GISAXS experiments in reflection at grazing incidence as well as SAXS experiments in transmission geometry. The X-ray flux on sample is comparable or higher than the one obtained at a comparable beamline at a second generation synchrotron radiation source.

  17. Low Temperature Reactions for the Preparation of Group 13-15 Materials from Organo-gallium(I) and -indium(I) Compounds

    National Research Council Canada - National Science Library

    Beachley, O

    1997-01-01

    ...) at 175 deg C and of neopentylgallium(I) Ga(CH2CMe3)n with P4 at 350- 400 deg C and with NH3 at 460-480 deg C in sealed tubes provide routes to indium phosphide, gallium phosphide and hexagonal gallium nitride, respectively...

  18. Noninvasive staging of lung cancer. Indications and limitations of gallium-67 citrate imaging

    International Nuclear Information System (INIS)

    Bekerman, C.; Caride, V.J.; Hoffer, P.B.; Boles, C.A.

    1990-01-01

    The results of evaluation of the hila and mediastinum with 67Ga scans are contradictory, as are the recommendations by different investigators on the use of 67Ga scintigraphy in the clinical evaluation of patients with primary lung carcinoma. Nevertheless, the economy and logistic simplicity of evaluating local and distant metastases with a single imaging procedure are attractive, especially because the symptoms may not enable the physician to make a correct identification of the organ systems affected by metastases. Neumann and Hoffer state that at present conventional Ga-67 scanning techniques cannot be recommended for preoperative staging of mediastinal lymph node metastases in lung cancer patients. According to Waxman, 67Ga scintigraphy, relative to other imaging modalities, is a sensitive indicator of hilar spread of a tumor. However, because of the normally high background activity within the sternum and spine, mediastinal abnormalities may be poorly detected. Since most pulmonary tumors metastasize via regional nodes to the pulmonary hilum and then to the mediastinum, the high sensitivity for the detection of pulmonary hilar abnormalities and the high specificity for detection of mediastinal lesions suggest that gallium scintigraphy is a valuable adjunctive test when used appropriately. The results obtained locally are probably the best guide for individual physicians in the selection of diagnostic tests for their patients. Gallium scans may thus be helpful in the clinical evaluation of patients with lung cancer. Although gallium scans identify mediastinal node involvement, there is considerable controversy over the relationship between the sensitivity and specificity of the method. By detecting distant extrathoracic metastases, the 67Ga scan may identify a small group of patients who can be spared a needless operation. 92 references

  19. A new automated NaCl based robust method for routine production of gallium-68 labeled peptides

    Science.gov (United States)

    Schultz, Michael K.; Mueller, Dirk; Baum, Richard P.; Watkins, G. Leonard; Breeman, Wouter A. P.

    2017-01-01

    A new NaCl based method for preparation of gallium-68 labeled radiopharmaceuticals has been adapted for use with an automated gallium-68 generator system. The method was evaluated based on 56 preparations of [68Ga]DOTATOC and compared to a similar acetone-based approach. Advantages of the new NaCl approach include reduced preparation time ( 97%), and specific activity (> 40 MBq nmole−1 [68Ga]DOTATOC) and is well-suited for clinical production of radiopharmaceuticals. PMID:23026223

  20. Engineering absorption and blackbody radiation in the far-infrared with surface phonon polaritons on gallium phosphide

    Energy Technology Data Exchange (ETDEWEB)

    Streyer, W.; Law, S.; Rosenberg, A.; Wasserman, D. [Department of Electrical and Computer Engineering, University of Illinois Urbana Champaign, Urbana, Illinois 61801 (United States); Roberts, C.; Podolskiy, V. A. [Department of Physics and Applied Physics, University of Massachusetts Lowell, Lowell, Massachusetts 01854 (United States); Hoffman, A. J. [Department of Electrical Engineering, University of Notre Dame, South Bend, Indiana 46556 (United States)

    2014-03-31

    We demonstrate excitation of surface phonon polaritons on patterned gallium phosphide surfaces. Control over the light-polariton coupling frequencies is demonstrated by changing the pattern periodicity and used to experimentally determine the gallium phosphide surface phonon polariton dispersion curve. Selective emission via out-coupling of thermally excited surface phonon polaritons is experimentally demonstrated. Samples are characterized experimentally by Fourier transform infrared reflection and emission spectroscopy, and modeled using finite element techniques and rigorous coupled wave analysis. The use of phonon resonances for control of emissivity and excitation of bound surface waves offers a potential tool for the exploration of long-wavelength Reststrahlen band frequencies.

  1. Pneumocystis pneumonia: importance of gallium scan for early diagnosis and description of a new immunoperoxidase technique to demonstrate Pneumocystis carinii

    International Nuclear Information System (INIS)

    Levin, M.; McLeod, R.; Young, Q.; Abrahams, C.; Chambliss, M.; Walzer, P.; Kabins, S.A.

    1983-01-01

    Pneumocystis pneumonia presented in a homosexual with fever, a normal chest radiograph, and pulmonary gallium uptake. Bronchial washings yielded Mycobaterium tuberculosis, but despite antituberculosis therapy he remained febrile, and gallium uptake in the lung increased. Subsequently, silver stain of transbronchial lung biopsy obtained 2 months earlier at the time that tuberculosis was diagnosed showed many Pneumocystis cysts in alveolar spaces. In contrast to Pneumocystis cysts in infected lung tissue from other humans, our patient's Pneumocystis cysts reacted more avidly with antiserum to rat Pneumocystis than with antiserum to human pneumocystis, raising the possibility that organisms that infect humans may have varied surface antigenic properties

  2. Efficient telecom to visible wavelength conversion in doubly resonant gallium phosphide microdisks

    Science.gov (United States)

    Lake, David P.; Mitchell, Matthew; Jayakumar, Harishankar; dos Santos, Laís Fujii; Curic, Davor; Barclay, Paul E.

    2016-01-01

    Resonant second harmonic generation between 1550 nm and 775 nm with normalized outside efficiency > 3.8 × 10 - 4 mW - 1 is demonstrated in a gallium phosphide microdisk supporting high-Q modes at visible ( Q ˜ 10 4 ) and infrared ( Q ˜ 10 5 ) wavelengths. The double resonance condition is satisfied for a specific pump power through intracavity photothermal temperature tuning using ˜ 360 μ W of 1550 nm light input to a fiber taper and coupled to a microdisk resonance. Power dependent efficiency consistent with a simple model for thermal tuning of the double resonance condition is observed.

  3. Optical polarization based logic functions (XOR or XNOR) with nonlinear Gallium nitride nanoslab.

    Science.gov (United States)

    Bovino, F A; Larciprete, M C; Giardina, M; Belardini, A; Centini, M; Sibilia, C; Bertolotti, M; Passaseo, A; Tasco, V

    2009-10-26

    We present a scheme of XOR/XNOR logic gate, based on non phase-matched noncollinear second harmonic generation from a medium of suitable crystalline symmetry, Gallium nitride. The polarization of the noncollinear generated beam is a function of the polarization of both pump beams, thus we experimentally investigated all possible polarization combinations, evidencing that only some of them are allowed and that the nonlinear interaction of optical signals behaves as a polarization based XOR. The experimental results show the peculiarity of the nonlinear optical response associated with noncollinear excitation, and are explained using the expression for the effective second order optical nonlinearity in noncollinear scheme.

  4. Local modification of the magnetic vortex-core velocity by gallium implantation

    Energy Technology Data Exchange (ETDEWEB)

    Langner, Hauke H., E-mail: hlangner@physnet.uni-hamburg.de; Vogel, Andreas; Beyersdorff, Björn [Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstr. 11, 20355 Hamburg (Germany); Weigand, Markus [Max-Planck-Institut für Intelligente Systeme, Heisenbergstraße 3, 70596 Stuttgart (Germany); Frömter, Robert; Peter Oepen, Hans; Meier, Guido [Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstr. 11, 20355 Hamburg (Germany); The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg (Germany)

    2014-03-14

    The dynamics of magnetic vortices in microsquares with local modifications of magnetic parameters and thickness are investigated. By implanting gallium ions with focussed ion beam into permalloy thin-film elements, we have locally tailored their magnetic properties and the layer thickness. The vortex of the Landau domain pattern of a square is resonantly excited to a gyrotropic motion and crosses regions with and without implantation. With time-resolved scanning transmission x-ray microscopy, we observe an abrupt change in the vortex velocity close to the borders between the two regions.

  5. Differentiation of posterior pararenal space infection from psoas abscess by gallium imaging

    Energy Technology Data Exchange (ETDEWEB)

    Bose, A.; Mishkin, F.; Delgado, J.

    1983-01-01

    Three of four patients whose cases fit the clinical description of psoas abscess proved on gallium imaging to have infection in the posterior pararenal space sparing the psoas muscle. This space provides a route for spread of infection connecting the spine, the anterior abdominal wall, the scrotum, the anterior thigh, and the gluteal region as demonstrated by the cases presented. Clinical differentiation between posterior pararenal space infection and psoas abscesses is difficult and CT studies may not demonstrate the process when the psoas space is not involved.

  6. Dry Etching Characteristics of Amorphous Indium-Gallium-Zinc-Oxide Thin Films

    International Nuclear Information System (INIS)

    Zheng Yanbin; Li Guang; Wang Wenlong; Li Xiuchang; Jiang Zhigang

    2012-01-01

    Amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistor (TFT) backplane technology is the best candidate for flat panel displays (FPDs). In this paper, a-IGZO TFT structures are described. The effects of etch parameters (rf power, dc-bias voltage and gas pressure) on the etch rate and etch profile are discussed. Three kinds of gas mixtures are compared in the dry etching process of a-IGZO thin films. Lastly, three problems are pointed out that need to be addressed in the dry etching process of a-IGZO TFTs. (plasma technology)

  7. Paired-pulse facilitation achieved in protonic/electronic hybrid indium gallium zinc oxide synaptic transistors

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Li Qiang, E-mail: guoliqiang@ujs.edu.cn; Ding, Jian Ning; Huang, Yu Kai [Micro/Nano Science & Technology Center, Jiangsu University, Zhenjiang, 212013 (China); Zhu, Li Qiang, E-mail: lqzhu@nimte.ac.cn [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2015-08-15

    Neuromorphic devices with paired pulse facilitation emulating that of biological synapses are the key to develop artificial neural networks. Here, phosphorus-doped nanogranular SiO{sub 2} electrolyte is used as gate dielectric for protonic/electronic hybrid indium gallium zinc oxide (IGZO) synaptic transistor. In such synaptic transistors, protons within the SiO{sub 2} electrolyte are deemed as neurotransmitters of biological synapses. Paired-pulse facilitation (PPF) behaviors for the analogous information were mimicked. The temperature dependent PPF behaviors were also investigated systematically. The results indicate that the protonic/electronic hybrid IGZO synaptic transistors would be promising candidates for inorganic synapses in artificial neural network applications.

  8. Paired-pulse facilitation achieved in protonic/electronic hybrid indium gallium zinc oxide synaptic transistors

    Directory of Open Access Journals (Sweden)

    Li Qiang Guo

    2015-08-01

    Full Text Available Neuromorphic devices with paired pulse facilitation emulating that of biological synapses are the key to develop artificial neural networks. Here, phosphorus-doped nanogranular SiO2 electrolyte is used as gate dielectric for protonic/electronic hybrid indium gallium zinc oxide (IGZO synaptic transistor. In such synaptic transistors, protons within the SiO2 electrolyte are deemed as neurotransmitters of biological synapses. Paired-pulse facilitation (PPF behaviors for the analogous information were mimicked. The temperature dependent PPF behaviors were also investigated systematically. The results indicate that the protonic/electronic hybrid IGZO synaptic transistors would be promising candidates for inorganic synapses in artificial neural network applications.

  9. The new barium mercuride BaHg6 and ternary indium and gallium derivatives

    International Nuclear Information System (INIS)

    Wendorff, Marco; Röhr, Caroline

    2013-01-01

    Highlights: ► The new binary Hg-rich mercuride BaHg 6 crystallizes with a singular structure type. ► Ternary In substituted compounds are isotypic, whereas Ga substituted compounds are only structurally related. ► Structure relation to other Hg-rich alkali and alkaline earth mercurides. ► Discussion of covalent and metallic bonding aspects, as found by structure features and band structure calculations. - Abstract: The new binary barium mercuride BaHg 6 and the derived ternary indium and gallium containing compounds BaIn 1.2 Hg 4.8 and BaGa 0.8 Hg 5.2 were synthesized from melts of the elements, which were slowly cooled from 500 to 200 °C. Their crystal structures have been determined by means of single crystal X-ray diffraction. The binary mercuride BaHg 6 (Pnma, a = 1338.9(3), b = 519.39(13), c = 1042.6(4) pm, Z = 4, R1 = 0.0885) and the isotypic indium substituted compound BaIn 1.2 Hg 4.8 as well as the structurally related gallium mercuride BaGa 0.8 Hg 5.2 (Cmcm, a = 729.77(7), b = 1910.1(2), c = 507.48(5) pm, Z = 4, R1 = 0.0606) crystallize with new structure types. Common features of both structures are planar nets of five- and eight-membered Hg rings, stacked perpendicular to the shortest axes. According to their lengths, the Hg–Hg bonds can be classified into three groups: strong, short ones (I, 285–292 pm), which are only found inside the nets, and longer distances (II), still carrying bond critical points, around 300 pm. Further contacts (III) serve to complete the coordination spheres of Hg/M (320–358 pm). The overall coordination numbers of Hg/M range from 10 to 13. The Ba cations are positioned in the centers of the octagons of the Hg/M nets, thus exhibiting a 5:8:5, i.e. 18, coordination by Hg/M atoms. DFT calculations of the electronic band structure of pure BaHg 6 and ordered models of the indium ( ′ BaInHg 5 ′ ) and the gallium ( ′ BaGaHg 5 ′ ) mercurides were performed using the FP-LAPW method. The calculated Bader charges

  10. Detection of spin-states in Mn-doped gallium arsenide films

    International Nuclear Information System (INIS)

    Hofer, Werner A; Palotas, Krisztian; Teobaldi, Gilberto; Sadowski, Janusz; Mikkelsen, Anders; Lundgren, Edvin

    2007-01-01

    We show that isolated magnetic dipoles centred at the position of manganese impurities in a gallium arsenide lattice lead to spin polarized states in the bandgap of the III-V semiconductor. Spectroscopy simulations with a tungsten tip agree well with experimental data; in this case, no difference can be observed for the two magnetic groundstates. But if the signal is read with a magnetic iron tip, it changes by a factor of up to 20, depending on the magnetic orientation of the Mn atom

  11. Growth of Gold-assisted Gallium Arsenide Nanowires on Silicon Substrates via Molecular Beam Epitaxy

    Directory of Open Access Journals (Sweden)

    Ramon M. delos Santos

    2008-06-01

    Full Text Available Gallium arsenide nanowires were grown on silicon (100 substrates by what is called the vapor-liquid-solid (VLS growth mechanism using a molecular beam epitaxy (MBE system. Good quality nanowires with surface density of approximately 108 nanowires per square centimeter were produced by utilizing gold nanoparticles, with density of 1011 nanoparticles per square centimeter, as catalysts for nanowire growth. X-ray diffraction measurements, scanning electron microscopy, transmission electron microscopy and Raman spectroscopy revealed that the nanowires are epitaxially grown on the silicon substrates, are oriented along the [111] direction and have cubic zincblende structure.

  12. Spray deposited gallium doped tin oxide thinfilm for acetone sensor application

    Science.gov (United States)

    Preethi, M. S.; Bharath, S. P.; Bangera, Kasturi V.

    2018-04-01

    Undoped and gallium doped (1 at.%, 2 at.% and 3 at.%) tin oxide thin films were prepared using spray pyrolysis technique by optimising the deposition conditions such as precursor concentration, substrate temperature and spraying rate. X-ray diffraction analysis revealed formation of tetragonally structured polycrystalline films. The SEM micrographs of Ga doped films showed microstructures. The electrical resistivity of the doped films was found to be more than that of the undoped films. The Ga-doped tin oxide thin films were characterised for gas sensors. 1 at.% Ga doped thin films were found to be better acetone gas sensor, showed 68% sensitivity at 350°C temperature.

  13. Effects of Radiation and Long-Term Thermal Cycling on EPC 1001 Gallium Nitride Transistors

    Science.gov (United States)

    Patterson, Richard L.; Scheick, Leif; Lauenstein, Jean-Marie; Casey, Megan; Hammoud, Ahmad

    2012-01-01

    Electronics designed for use in NASA space missions are required to work efficiently and reliably under harsh environment conditions. These include radiation, extreme temperatures, and thermal cycling, to name a few. Data obtained on long-term thermal cycling of new un-irradiated and irradiated samples of EPC1001 gallium nitride enhancement-mode transistors are presented. This work was done by a collaborative effort including GRC, GSFC, and support the NASA www.nasa.gov 1 JPL in of Electronic Parts and Packaging (NEPP) Program

  14. Pulsed electron-beam annealing of selenium-implanted gallium arsenide

    International Nuclear Information System (INIS)

    Inada, T.; Tokunaga, K.; Taka, S.

    1979-01-01

    Electrical properties of selenium-implanted gallium arsenide annealed by a single shot of high-power pulsed electron beams have been investigated by differential Hall-effect and sheet-resistivity measurements. It has been shown that higher electrical activation of implanted selenium can be obtained after electron-beam annealing at an incident energy density of 1.2 J/cm 2 , independent of heating of GaAs substrate during implantation. Measured carrier concentrations exhibit uniformly distributed profiles having carrier concentrations of 2--3 x 10 19 /cm 3 , which is difficult to realize by conventional thermal annealing

  15. Magnetoelectric effect in a sandwich structure of gallium arsenide–nickel–tin–nickel

    Science.gov (United States)

    Galichyan, T. A.; Filippov, D. A.; Tihonov, A. A.; Laletin, V. M.; Firsova, T. O.; Manicheva, I. N.

    2018-04-01

    The results of investigation of the magnetoelectric effect in a nickel-tin-nickel sandwich structure obtained by galvanic deposition of gallium arsenide on a substrate are presented. The technology of constructing such structures is described and the experimental results of the frequency dependence of the effect are presented. It is shown that the use of tin as an intermediate layer reduces the mechanical stresses resulting from the incommensurability of the phases, which permits obtaining qualitative structures with the nickel thickness of about 70 μm. The resulting structures exhibit good adhesion between the layers and have a high quality factor.

  16. Differentiation of posterior pararenal space infection from psoas abscess by gallium imaging

    International Nuclear Information System (INIS)

    Bose, A.; Mishkin, F.; Delgado, J.

    1983-01-01

    Three of four patients whose cases fit the clinical description of psoas abscess proved on gallium imaging to have infection in the posterior pararenal space sparing the psoas muscle. This space provides a route for spread of infection connecting the spine, the anterior abdominal wall, the scrotum, the anterior thigh, and the gluteal region as demonstrated by the cases presented. Clinical differentiation between posterior pararenal space infection and psoas abscesses is difficult and CT studies may not demonstrate the process when the psoas space is not involved

  17. Femtosecond Nonlinearities in Indium Gallium Arsenic Phosphide Diode Lasers

    Science.gov (United States)

    Hall, Katherine Lavin

    Semiconductor optical amplifiers are receiving increasing attention for possible applications to broadband optical communication and switching systems. In this thesis we report the results of an extensive experimental study of the ultrafast gain and refractive index nonlinearities in 1.5 μm InGaAsP laser diode amplifiers. The temporal resolution afforded by the femtosecond optical pulses used in these experiments allows us to study carrier interactions with other carriers as well as carrier interactions with the lattice. The 100-200 fs optical pulses used in the pump -probe experiments are generated by an Additive Pulse Modelocked color center laser. The measured group velocity dispersion in the diodes ranged from -0.6 to -0.95 mu m^{-1 }. Differences in the group velocity for TE - and TM-polarized pulses suggested that cross-polarized pump-probe pulses walk off from each other in the diode. This walk-off can diminish the time resolution of some experiments. A novel heterodyne pump-probe technique was developed to distinguish collinear, copolarized, pump and probe pulses that were nominally at the same wavelength. Comparing cross-polarized and copolarized pump-probe results yielded new information about the physical mechanisms responsible for nonlinear gain in the diodes. We observed a gain compression across the entire bandwidth of the diode, associated with carrier heating. The hot carrier distribution cooled back to the lattice temperature with a 0.6 to 1.0 ps time constant, depending on the device structure. In addition, we observed a 0.1 to 0.25 ps delay in onset of carrier heating. Large gain compression due to two photon absorption was also observed. A small portion of the nonlinear gain is attributed to spectral hole burning. Pulsewidth-dependent output saturation energies were explained by a rate equation model that included the effect of carrier heating. Measurements of pump-induced probe phase changes revealed index nonlinearities due to delayed carrier

  18. Efficacy of 67 gallium ECT imaging in lymphoma, infection, and lung carcinoma: A comparison with planar imaging

    International Nuclear Information System (INIS)

    Harwood, S.J.; Anderson, M.W.; Klein, R.C.; Friedman, B.I.; Carroll, R.G.

    1984-01-01

    Emission computed tomography (ECT) studies were performed on a GE 400 A/T camera and ADAC computers (system 3 and system 3300). Thirty-three sets of ECT and planar images were obtained in 20 patients over a six month period. Imaging was performed 48 hours after the intravenous administration of 5 mc of Gallium 67 citrate. No bowel preparation was employed. Comparison is made of the initial nuclear medicine report derived from planar and ECT imaging aided by clinical knowledge versus the consensus opinion of two nuclear medicine physicians reading the planar images along with minimal clinical information. The lymphoma series consists of 18 scans in 10 patients. There were 5 scans in which a false negative planar interpretation was changed to a true positive ECT interpretation. Sensitivity of planar imaging for lymphoma was 58% which rose to 100% with addition of ECT information. There were no false positives by either technique. There were 5 sets of scans in 5 lung carcinoma patients. Sensitivity of the planar images was 60% because of 2 false negative results. Sensitivity of the ECT technique was 100%. There were no false positives. The infection series consists of 10 scans in 5 patients. Sensitivity of ECT was 100%, sensitivity of planar was 66%. There was 1 false positive planar. For the total series the accuracy of planar imaging was 69% and the predictive value of a negative planar interpretation was 44%. Corresponding values for ECT imaging were 100%. The authors' experience demonstrates significant increase in sensitivity without loss of specificity resulting from the use of Emission Computed Tomography in both chest and abdomen in patients with lymphoma, infection, and lung cancer

  19. Advanced Epi Tools for Gallium Nitride Light Emitting Diode Devices

    Energy Technology Data Exchange (ETDEWEB)

    Patibandla, Nag; Agrawal, Vivek

    2012-12-01

    Over the course of this program, Applied Materials, Inc., with generous support from the United States Department of Energy, developed a world-class three chamber III-Nitride epi cluster tool for low-cost, high volume GaN growth for the solid state lighting industry. One of the major achievements of the program was to design, build, and demonstrate the world’s largest wafer capacity HVPE chamber suitable for repeatable high volume III-Nitride template and device manufacturing. Applied Materials’ experience in developing deposition chambers for the silicon chip industry over many decades resulted in many orders of magnitude reductions in the price of transistors. That experience and understanding was used in developing this GaN epi deposition tool. The multi-chamber approach, which continues to be unique in the ability of the each chamber to deposit a section of the full device structure, unlike other cluster tools, allows for extreme flexibility in the manufacturing process. This robust architecture is suitable for not just the LED industry, but GaN power devices as well, both horizontal and vertical designs. The new HVPE technology developed allows GaN to be grown at a rate unheard of with MOCVD, up to 20x the typical MOCVD rates of 3{micro}m per hour, with bulk crystal quality better than the highest-quality commercial GaN films grown by MOCVD at a much cheaper overall cost. This is a unique development as the HVPE process has been known for decades, but never successfully commercially developed for high volume manufacturing. This research shows the potential of the first commercial-grade HVPE chamber, an elusive goal for III-V researchers and those wanting to capitalize on the promise of HVPE. Additionally, in the course of this program, Applied Materials built two MOCVD chambers, in addition to the HVPE chamber, and a robot that moves wafers between them. The MOCVD chambers demonstrated industry-leading wavelength yield for GaN based LED wafers and industry

  20. Microfabrication in free-standing gallium nitride using UV laser micromachining

    International Nuclear Information System (INIS)

    Gu, E.; Howard, H.; Conneely, A.; O'Connor, G.M.; Illy, E.K.; Knowles, M.R.H.; Edwards, P.R.; Martin, R.W.; Watson, I.M.; Dawson, M.D.

    2006-01-01

    Gallium nitride (GaN) and related alloys are important semiconductor materials for fabricating novel photonic devices such as ultraviolet (UV) light-emitting diodes (LEDs) and vertical cavity surface-emitting lasers (VCSELs). Recent technical advances have made free-standing GaN substrates available and affordable. However, these materials are strongly resistant to wet chemical etching and also, low etch rates restrict the use of dry etching. Thus, to develop alternative high-resolution processing for these materials is increasingly important. In this paper, we report the fabrication of microstructures in free-standing GaN using pulsed UV lasers. An effective method was first developed to remove the re-deposited materials due to the laser machining. In order to achieve controllable machining and high resolution in GaN, machining parameters were carefully optimised. Under the optimised conditions, precision features such as holes (through holes, blind or tapered holes) on a tens of micrometer length scale have been machined. To fabricate micro-trenches in GaN with vertical sidewalls and a flat bottom, different process strategies of laser machining were tested and optimised. Using this technique, we have successfully fabricated high-quality micro-trenches in free-standing GaN with various widths and depths. The approach combining UV laser micromachining and other processes is also discussed. Our results demonstrate that the pulsed UV laser is a powerful tool for fabricating precision microstructures and devices in gallium nitride

  1. Trapping of positron in gallium arsenide: evidencing of vacancies and of ions with a negative charge

    International Nuclear Information System (INIS)

    Pierre, F.

    1989-12-01

    Vacancy type defects in Ga As as grown and irradiated by electrons are characterized by lifetime of positrons. Positron lifetime increases from 230 ps to 258 and 295 ps in presence of native vacancies in n type Ga As. Configuration of native vacancies changes when Fermi level crosses energy levels localized in the forbidden zone at 0.035eV and at 0.10eV from the bottom of the conduction band. Native vacancies are identified to arsenic vacancies with or without other point defects. Positron lifetime increases from 230 to 260 ps in presence of vacancies produced by low temperature irradiation negative ions are also produced. In irradiated Ga As, these ions trap positrons in competition with vacancies produced by irradiation, showing they have a negative charge. Two annealing zones between 180-300K and 300-600K are presented by vacancies. Ions do not anneal below ambient temperature. Vacancies and negative ions are identified respectively to gallium vacancies and gallium antisite [fr

  2. A noise thermometry investigation of the melting point of gallium at the NIM

    Science.gov (United States)

    Zhang, J. T.; Xue, S.

    2006-06-01

    This paper describes a study of the melting point of gallium with the new NIM Johnson noise thermometer (JNT). The new thermometer adopts the structure of switching correlator and commutator with the reference resistor maintained at the triple point of water. The electronic system of the new thermometer is basically the same as the current JNT, but the preamplifiers have been improved slightly. This study demonstrates that examining the characteristics of the noise signals in the frequency domain is of critical importance in constructing an improved new thermometer, where a power spectral analysis is found to be critical in establishing appropriate grounding for the new thermometer. The new JNT is tested on measurements of the thermodynamic temperature of the melting point of gallium, which give the thermodynamic temperature of 302.9160 K, with an overall integration time of 190 h and a combined standard uncertainty of 9.4 mK. The uncertainty analysis indicates that a standard combined uncertainty of 3 mK could be achieved with the new thermometer over an integration period of 1750 h.

  3. Spectrophotometric Determination of Gallium(III with 4-(2-Pyridylazo-resorcinol and Nitron

    Directory of Open Access Journals (Sweden)

    Petya Vassileva Racheva

    2015-07-01

    Full Text Available The formation and liquid-liquid extraction of ion-association complex between gallium(III − 4-(2-pyridylazo-resorcinol (PAR – 1,4-diphenyl-3-(phenylamino-1H-1,2,4-triazole (nitron, Nt, water and chloroform were studied. The optimum conditions for gallium(III extraction as an ion-association complex, (NtH+[Ga3+(PAR2]-, were found: pH, concentration of the reagents and shaking time. The following key constants were calculated: constant of extraction (logKex = 6.28 ± 0.07, constant of association (logβ = 4.98 ± 0.05, constant of distribution (logKD = 1.30 ± 0.02 and recovery factor (R / % = 95.17 ± 0.02. Beerʼs law is obeyed for Ga(III concentration up to 0.8 μg cm-3 with apparent molar absorptivity of (10.3 ± 0.4×104 dm-3 mol-1 cm-1 at λmax = 510 nm. Some additional characteristics, such as limit of detection (LOD = 0.072 μg cm-3, limit of quantification (LOQ = 0.24 μg cm-3 and Sandellʼs sensitivity (SS = 0.000675 ng cm-2 were estimated as well.

  4. An electron beam induced current study of gallium nitride and diamond materials

    International Nuclear Information System (INIS)

    Cropper, A.D.; Moore, D.J.; Scott, C.S.; Green, R.

    1995-01-01

    The continual need for microelectronic devices that operate under severe electronic and environmental conditions (high temperature, high frequency, high power, and radiation tolerance) has sustained research in wide bandgap semiconductor materials. The properties suggest these wide-bandgap semiconductor materials have tremendous potential for military and commercial applications. High frequency bipolar transistors and field effect transistors, diodes, and short wavelength optical devices have been proposed using these materials. Although research efforts involving the study of transport properties in Gallium Nitride (GaN) and Diamond have made significant advances, much work is still needed to improve the material quality so that the electrophysical behavior of device structures can be further understood and exploited. Electron beam induced current (EBIC) measurements can provide a method of understanding the transport properties in Gallium Nitride (GaN) and Diamond. This technique basically consists of measuring the current or voltage transient response to the drift and diffusion of carriers created by a short-duration pulse of radiation. This method differs from other experimental techniques because it is based on a fast transient electron beam probe created from a high speed, laser pulsed photoemission system

  5. Immune complexes, gallium lung scans, and bronchoalveolar lavage in idiopathic interstitial pneumonitis-fibrosis

    International Nuclear Information System (INIS)

    Gelb, A.F.; Dreisen, R.B.; Epstein, J.D.; Silverthorne, J.D.; Bickel, Y.; Fields, M.; Border, W.A.; Taylor, C.R.

    1983-01-01

    We obtained results of lung immune complexes (LIC), circulating immune complexes (CIC), 48-hour gallium lung scans (scans), bronchoalveolar lavage (BAL), and pulmonary function tests in 20 patients with idiopathic interstitial pneumonitis-fibrosis. Sixteen patients had predominantly interstitial (13 cases UIP) and/or intraalveolar (3 cases DIP) cellular disease (group 1). Prior to corticosteroid therapy in group 1, scans were positive in 75 percent, CIC were elevated in 86 percent, LIC were present in 64 percent, and BAL was abnormal in 90 percent. Duration of follow-up after treatment was 3.5 +/- 1.0 year. In group 1 after treatment with corticosteroids in 13 patients and corticosteroids and penicillamine (three patients) and plasmapheresis (one patient), only four patients remain stable or improved. After corticosteroid therapy, elevated CIC returned to normal values despite progressive patient deterioration. In three patients, lung immune complexes were still detected after circulating immune complexes had returned to normal after corticosteroid therapy. In group 2 were four patients with fibrotic disease; scans and CIC were uniformly negative, LIC were weakly present in only one patient, and BAL was abnormal in all. Despite corticosteroid therapy, all have died or deteriorated. These results suggest that positive gallium lung scans, BAL, circulating immune complexes, and to a lesser extent, lung immune complexes are associated with the cellular phase of interstitial pneumonia, but do not reliably identify a corticosteroid-responsive group

  6. Liquid gallium jet as a limiter in tokamak: design of the stand

    International Nuclear Information System (INIS)

    Lielausis, O.; Platacis, E.; Klukins, A.

    2005-01-01

    Full text: Plasma facing surfaces should be considered as the most loaded components of the proposed fusion devices. Load densities (up to 1 GW/m 2 ) would result in unacceptably high levels of thermal stresses and erosion. Solutions have been proposed when plasma is contacting not a solid material but a liquid metal in permanent motion. Usually, because of its low Z-number, lithium is considered as the most compatible with plasma. In the given research gallium is used - an essentially more convenient in practice material, outstanding by its low saturated vapor pressure. On tokamak ISTTOK (Portugal, R=0.46m; a=0.085m; B T =0.45 T; I p =8 kA) it is proposed to replace the existing metallic limiter by a liquid gallium jet. The jet forming nozzle is connected with the constant pressure vessel (at the level 1.3 m) by a 1/4 '' SS tube. For an exact determination of the jets length on the level 0.7 m an electrically controlled flow interrupting valve is installed. The metal is brought up into the pressure vessel by an e.m. pump on permanent magnets. The loop is designed in such a way that the liquid metal remains properly insulated both from the plasma vessel walls as well as from the plasma potential

  7. Gallium imaging of esophageal carcinoma: Increased sensitivity with lateral views of the thorax

    International Nuclear Information System (INIS)

    Sostre, S.; Romero, I.; Rivera, J.V.; Baez, L.; Cintron, E.

    1990-01-01

    Ga-67 imaging has not been very successful in the detection of esophageal carcinoma. In most reports, sensitivity for the primary tumor ranged from 25-61%, but imaging had been done only in anterior and posterior (A-P) projections. We performed gallium scans in 30 patients with esophageal carcinoma, adding lateral views to the routine A-P projections, to study the effect of lateral views on tumor detection. The A-P views detected only 57% of the tumors while the right lateral visualized 89%, and the left lateral detected 100%. Some lesions may be hidden by the sternum and the spine in the routine A-P views. Previous disappointments with Ga-67 imaging of esophageal carcinoma were probably due to this technical factor. Being gallium-avid, esophageal tumors deserve further studies with this agent to determine the role of Ga-67 imaging in this condition. These studies should be performed with multiple views of the thorax or, better yet, with SPECT imaging of the chest, to circumvent the problem of sternum and spine interference

  8. Morphology evolution of hydrothermally grown ZnO nanostructures on gallium doping and their defect structures

    Energy Technology Data Exchange (ETDEWEB)

    Pineda-Hernandez, G. [Facultad de Ingenieria Quimica, Benemerita Universidad Autonoma de Puebla, C.P. 72570 Puebla, Pue. (Mexico); Escobedo-Morales, A., E-mail: alejandroescobedo@hotmail.com [Facultad de Ingenieria Quimica, Benemerita Universidad Autonoma de Puebla, C.P. 72570 Puebla, Pue. (Mexico); Pal, U. [Instituto de Fisica, Benemerita Universidad Autonoma de Puebla, Apdo. Postal J-48, C.P. 72570 Puebla, Pue. (Mexico); Chigo-Anota, E. [Facultad de Ingenieria Quimica, Benemerita Universidad Autonoma de Puebla, C.P. 72570 Puebla, Pue. (Mexico)

    2012-08-15

    In the present article, the effect of gallium doping on the morphology, structural, and vibrational properties of hydrothermally grown ZnO nanostructures has been studied. It has been observed that incorporated gallium plays an important role on the growth kinetics and hence on the morphology evolution of the ZnO crystals. Ga doping in high concentration results in the contraction of ZnO unit cell, mainly along c-axis. Although Ga has high solubility in ZnO, heavy doping promotes the segregation of Ga atoms as a secondary phase. Incorporated Ga atoms strongly affect the vibrational characteristics of ZnO lattice and induce anomalous Raman modes. Possible mechanisms of morphology evolution and origin of anomalous Raman modes in Ga doped ZnO nanostructures are discussed. -- Highlights: Black-Right-Pointing-Pointer Ga doped ZnO nanostructures were successfully grown by hydrothermal chemical route. Black-Right-Pointing-Pointer Ga doping has strong effect on the resulting morphology of ZnO nanostructures. Black-Right-Pointing-Pointer Anomalous vibrational modes in wurtzite ZnO lattice are induced by Ga doping. Black-Right-Pointing-Pointer Incorporated Ga atoms accommodate at preferential lattice sites.

  9. High-fluence hyperthermal ion irradiation of gallium nitride surfaces at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Finzel, A.; Gerlach, J.W., E-mail: juergen.gerlach@iom-leipzig.de; Lorbeer, J.; Frost, F.; Rauschenbach, B.

    2014-10-30

    Highlights: • Irradiation of gallium nitride films with hyperthermal nitrogen ions. • Surface roughening at elevated sample temperatures was observed. • No thermal decomposition of gallium nitride films during irradiation. • Asymmetric surface diffusion processes cause local roughening. - Abstract: Wurtzitic GaN films deposited on 6H-SiC(0001) substrates by ion-beam assisted molecular-beam epitaxy were irradiated with hyperthermal nitrogen ions with different fluences at different substrate temperatures. In situ observations with reflection high energy electron diffraction showed that during the irradiation process the surface structure of the GaN films changed from two dimensional to three dimensional at elevated temperatures, but not at room temperature. Atomic force microscopy revealed an enhancement of nanometric holes and canyons upon the ion irradiation at higher temperatures. The roughness of the irradiated and heated GaN films was clearly increased by the ion irradiation in accordance with x-ray reflectivity measurements. A sole thermal decomposition of the films at the chosen temperatures could be excluded. The results are discussed taking into account temperature dependent sputtering and surface uphill adatom diffusion as a function of temperature.

  10. Potential aluminium(III)- and gallium(III)-selective optical sensors based on porphyrazines.

    Science.gov (United States)

    Goslinski, Tomasz; Tykarska, Ewa; Kryjewski, Michal; Osmalek, Tomasz; Sobiak, Stanislaw; Gdaniec, Maria; Dutkiewicz, Zbigniew; Mielcarek, Jadwiga

    2011-01-01

    Porphyrazines possessing non-coordinating alkyl (propyl) and aralkyl (4-tert-butylphenyl) groups in the periphery were studied as optical sensors for a set of mono-, di- and trivalent cations. Investigated porphyrazines in the UV-Vis monitored titrations revealed significant responses towards aluminium and gallium cations, unlike other metal ions studied. Additionally, porphyrazine possessing 4-tert-butylphenyl peripheral substituents showed sensor property towards ruthenium cation and was chosen for further investigation. The presence of isosbestic points in absorption spectra for its titration with aluminium, gallium and ruthenium cations, accompanied by a linear Benesi-Hildebrand plot, proved complex formation. The continuous variation method was used to determine binding stoichiometry in 1:1 porphyrazine-metal ratio. X-Ray studies and density functional theory calculations were employed to investigate octa(4-tert-butylphenyl)porphyrazine structure. The results helped to explain the observed selectivity towards certain ions. Interaction between ion and porphyrazine meso nitrogen in a Lewis acid-Lewis base manner is proposed.

  11. THE QUANTUM-WELL STRUCTURES OF SELF ELECTROOPTIC-EFFECT DEVICES AND GALLIUM-ARSENIDE

    Directory of Open Access Journals (Sweden)

    Mustafa TEMİZ

    1996-02-01

    Full Text Available Multiple quantum-well (MQW electroabsorptive self electro optic-effect devices (SEEDs are being extensively studied for use in optical switching and computing. The self electro-optic-effect devices which has quantum-well structures is a new optoelectronic technology with capability to obtain both optical inputs and outputs for Gallium-Arsenide/Aluminum Gallium-Arsenide (GaAs/AlGaAs electronic circuits. The optical inputs and outputs are based on quantum-well absorptive properties. These quantum-well structures consist of many thin layers of semiconductors materials of GaAs/AlGaAs which have emerged some important directions recently. The most important advance in the physics of these materials since the early days has been invention of the heterojunction structures which is based at present on GaAs technology. GaAs/AlGaAs structures present some important advantages to relevant band gap and index of refraction which allow to form the quantum-well structures and also to make semiconductor lasers, dedectors and waveguide optical switches.

  12. Chemical exfoliation and optical characterization of threading-dislocation-free gallium-nitride ultrathin nanomembranes

    KAUST Repository

    Elafandy, Rami T.

    2014-11-13

    Semiconductor nanostructures have generated tremendous scientific interests as well as practical applications stemming from the engineering of low dimensional physics phenomena. Unlike 0D and 1D nanostructures, such as quantum dots and nanowires, respectively, 2D structures, such as nanomembranes, are unrivalled in their scalability for high yield manufacture and are less challenging in handling with the current transfer techniques. Furthermore, due to their planar geometry, nanomembranes are compatible with the current complementary metal oxide semiconductor (CMOS) technology. Due to these superior characteristics, there are currently different techniques in exfoliating nanomembranes with different crystallinities, thicknesses and compositions. In this work we demonstrate a new facile technique of exfoliating gallium nitride (GaN) nanomembranes with novel features, namely with the non-radiative cores of their threading-dislocations (TDs) being etched away. The exfoliation process is based on engineering the gallium vacancy (VGa) density during the GaN epitaxial growth with subsequent preferential etching. Based on scanning and transmission electron microscopies, as well as micro-photoluminescence measurements, a model is proposed to uncover the physical processes underlying the formation of the nanomembranes. Raman measurements are also performed to reveal the internal strain within the nanomembranes. After transferring these freely suspended 25 nm thin GaN nanomembranes to other substrates, we demonstrate the temperature dependence of their bandgap by photoluminescence technique, in order to shed light on the internal carrier dynamics. © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  13. Optical properties of pure and Ce3+ doped gadolinium gallium garnet crystals and epitaxial layers

    International Nuclear Information System (INIS)

    Syvorotka, I.I.; Sugak, D.; Wierzbicka, A.; Wittlin, A.; Przybylińska, H.; Barzowska, J.; Barcz, A.; Berkowski, M.; Domagała, J.; Mahlik, S.; Grinberg, M.; Ma, Chong-Geng

    2015-01-01

    Results of X-ray diffraction and low temperature optical absorption measurements of cerium doped gadolinium gallium garnet single crystals and epitaxial layers are reported. In the region of intra-configurational 4f–4f transitions the spectra of the bulk crystals exhibit the signatures of several different Ce 3+ related centers. Apart from the dominant center, associated with Ce substituting gadolinium, at least three other centers are found, some of them attributed to the so-called antisite locations of rare-earth ions in the garnet host, i.e., in the Ga positions. X-ray diffraction data prove lattice expansion of bulk GGG crystals due to the presence of rare-earth antisites. The concentration of the additional Ce-related centers in epitaxial layers is much lower than in the bulk crystals. However, the Ce-doped layers incorporate a large amount of Pb from flux, which is the most probable source of nonradiative quenching of Ce luminescence, not observed in crystals grown by the Czochralski method. - Highlights: • Ce 3+ multicenters found in Gadolinium Gallium Garnet crystals and epitaxial layers. • High quality epitaxial layers of pure and Ce-doped GGG were grown. • Luminescence quenching of Ce 3+ by Pb ions from flux detected in GGG epitaxial layers. • X-ray diffraction allows measuring the amount of the rare-earth antisites in GGG

  14. Solvothermal synthesis of gallium-indium-zinc-oxide nanoparticles for electrolyte-gated transistors.

    Science.gov (United States)

    Santos, Lídia; Nunes, Daniela; Calmeiro, Tomás; Branquinho, Rita; Salgueiro, Daniela; Barquinha, Pedro; Pereira, Luís; Martins, Rodrigo; Fortunato, Elvira

    2015-01-14

    Solution-processed field-effect transistors are strategic building blocks when considering low-cost sustainable flexible electronics. Nevertheless, some challenges (e.g., processing temperature, reliability, reproducibility in large areas, and cost effectiveness) are requirements that must be surpassed in order to achieve high-performance transistors. The present work reports electrolyte-gated transistors using as channel layer gallium-indium-zinc-oxide nanoparticles produced by solvothermal synthesis combined with a solid-state electrolyte based on aqueous dispersions of vinyl acetate stabilized with cellulose derivatives, acrylic acid ester in styrene and lithium perchlorate. The devices fabricated using this approach display a ION/IOFF up to 1 × 10(6), threshold voltage (VTh) of 0.3-1.9 V, and mobility up to 1 cm(2)/(V s), as a function of gallium-indium-zinc-oxide ink formulation and two different annealing temperatures. These results validates the usage of electrolyte-gated transistors as a viable and promising alternative for nanoparticle based semiconductor devices as the electrolyte improves the interface and promotes a more efficient step coverage of the channel layer, reducing the operating voltage when compared with conventional dielectrics gating. Moreover, it is shown that by controlling the applied gate potential, the operation mechanism of the electrolyte-gated transistors can be modified from electric double layer to electrochemical doping.

  15. Preparation of gallium-68 radiopharmaceuticals for positron tomography. Progress report, November 1, 1977-October 31, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Welch, M.J.

    1980-06-01

    Although the germanium-68 ..-->.. gallium-68 generator is probably the only source of positron-emitting radionuclides that could enable the widespread application of positron tomography, the commercially available /sup 68/Ga//sup 68/Ge generator system suffers from several major disadvantages. The most important of these is that the generator is eluted with EDTA, which forms a very strong chelate with gallium. In order to produce radiopharmaceuticals other than /sup 68/Ga-EDTA, it is first necessary to break the stable EDTA complex and remove all traces of EDTA. This procedure adds several steps and a significant amount of time to procedures for preparing /sup 68/Ga-radiopharmaceuticals. We have developed a new generator using a solvent extraction system which will produce /sup 68/Ga-oxine (8-hydroxyquinoline), a weak chelate. Using this agent we have synthesized several /sup 68/Ga-radiopharmaceuticals and tested them in vitro and in vivo. We have also carried out some preliminary studies to compare generator systems which produce /sup 68/Ga in an ionic form. Attempts have been made using polarographic and chromatographic techniques, and in vivo distribution data to investigate the stability of radiogallium complexes with a series of potentially lipophilic complexing agents.

  16. Organometallic model complexes elucidate the active gallium species in alkane dehydrogenation catalysts based on ligand effects in Ga K-edge XANES

    Energy Technology Data Exchange (ETDEWEB)

    Getsoian, Andrew “Bean”; Das, Ujjal; Camacho-Bunquin, Jeffrey; Zhang, Guanghui; Gallagher, James R.; Hu, Bo; Cheah, Singfoong; Schaidle, Joshua A.; Ruddy, Daniel A.; Hensley, Jesse E.; Krause, Theodore R.; Curtiss, Larry A.; Miller, Jeffrey T.; Hock, Adam S.

    2016-01-01

    Gallium-modified zeolites are known catalysts for the dehydrogenation of alkanes, reactivity that finds industrial application in the aromatization of light alkanes by Ga-ZSM5. While the role of gallium cations in alkane activation is well known, the oxidation state and coordination environment of gallium under reaction conditions has been the subject of debate. Edge shifts in Ga K-edge XANES spectra acquired under reaction conditions have long been interpreted as evidence for reduction of Ga(III) to Ga(I). However, a change in oxidation state is not the only factor that can give rise to a change in the XANES spectrum. In order to better understand the XANES spectra of working catalysts, we have synthesized a series of molecular model compounds and grafted surface organometallic Ga species and compared their XANES spectra to those of gallium-based catalysts acquired under reducing conditions. We demonstrate that changes in the identity and number of gallium nearest neighbors can give rise to changes in XANES spectra similar to those attributed in literature to changes in oxidation state. Specifically, spectral features previously attributed to Ga(I) may be equally well interpreted as evidence for low-coordinate Ga(III) alkyl or hydride species. These findings apply both to gallium-impregnated zeolite catalysts and to silica-supported single site gallium catalysts, the latter of which is found to be active and selective for dehydrogenation of propane and hydrogenation of propylene.

  17. Structural and electrooptical characteristics of quantum dots emitting at 1.3 μm on gallium arsenide

    DEFF Research Database (Denmark)

    Fiore, A.; Oesterle, U.; Stanley, R.P.

    2001-01-01

    We present a comprehensive study of the structural and emission properties of self-assembled InAs quantum dots emitting at 1.3 mum. The dots are grown by molecular beam epitaxy on gallium arsenide substrates. Room-temperature emission at 1.3 mum is obtained by embedding the dots in an InGaAs layer...

  18. Negative permittivity of ZnO thin films prepared from aluminum and gallium doped ceramics via pulsed-laser deposition

    DEFF Research Database (Denmark)

    Bodea, M. A.; Sbarcea, G.; Naik, G. V.

    2013-01-01

    Aluminum and gallium doped zinc oxide thin films with negative dielectric permittivity in the near infrared spectral range are grown by pulsed laser deposition. Composite ceramics comprising ZnO and secondary phase Al2O3 or Ga2O3 are employed as targets for laser ablation. Films deposited on glass...

  19. An assessment of the validity of cerium oxide as a surrogate for plutonium oxide gallium removal studies

    International Nuclear Information System (INIS)

    Kolman, D.G.; Park, Y.; Stan, M.; Hanrahan, R.J. Jr.; Butt, D.P.

    1999-01-01

    Methods for purifying plutonium metal have long been established. These methods use acid solutions to dissolve and concentrate the metal. However, these methods can produce significant mixed waste, that is, waste containing both radioactive and chemical hazards. The volume of waste produced from the aqueous purification of thousands of weapons would be expensive to treat and dispose. Therefore, a dry method of purification is highly desirable. Recently, a dry gallium removal research program commenced. Based on initial calculations, it appeared that a particular form of gallium (gallium suboxide, Ga 2 O) could be evaporated from plutonium oxide in the presence of a reducing agent, such as small amounts of hydrogen dry gas within an inert environment. Initial tests using ceria-based material (as a surrogate for PuO 2 ) showed that thermally-induced gallium removal (TIGR) from small samples (on the order of one gram) was indeed viable. Because of the expense and difficulty of optimizing TIGR from plutonium dioxide, TIGR optimization tests using ceria have continued. This document details the relationship between the ceria surrogate tests and those conducted using plutonia

  20. Enhanced, robust light-driven H2 generation by gallium-doped titania nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Si [Chemistry Department, Brookhaven National Laboratory; Upton; USA; Department of Chemistry, Stony Brook University, Stony Brook; USA; Nguyen-Phan, Thuy-Duong [Chemistry Department, Brookhaven National Laboratory; Upton; USA; Vovchok, Dimitriy [Chemistry Department, Brookhaven National Laboratory; Upton; USA; Department of Chemistry, Stony Brook University, Stony Brook; USA; Waluyo, Iradwikanari [Photon Sciences Division, National Synchrotron Light Source II, Brookhaven National Laboratory; Upton; USA; Palomino, Robert M. [Chemistry Department, Brookhaven National Laboratory; Upton; USA; Gamalski, Andrew D. [Center for Functional Nanomaterials, Brookhaven National Laboratory; Upton; USA; Barrio, Laura [CSIC – Instituto de Catalisis y Petroleoquimica Cantoblanco; E-28049 Madrid; Spain; Xu, Wenqian [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory; Argonne; USA; Polyansky, Dmitry E. [Chemistry Department, Brookhaven National Laboratory; Upton; USA; Rodriguez, José A. [Chemistry Department, Brookhaven National Laboratory; Upton; USA; Department of Chemistry, Stony Brook University, Stony Brook; USA; Senanayake, Sanjaya D. [Chemistry Department, Brookhaven National Laboratory; Upton; USA

    2017-12-14

    Successful introduction of gallium ions into TiO2nanoparticles significantly promotes the H2evolution activity and stability, increasing the opportunities for designing promising photocatalysts for green fuel production.

  1. Influence of boat material on the structure, stoichiometry and optical properties of gallium sulphide films prepared by thermal evaporation

    International Nuclear Information System (INIS)

    Rao, Pritty; Kumar, Sanjiv; Sahoo, N.K.

    2015-01-01

    The paper describes the deposition of thin films of gallium sulphide on soda-lime glass substrates by thermal evaporation of chemically synthesized powders consisting of gallium sulphide and gallium oxyhydroxide from a Mo or Ta boat and the evolution of their compositional, structural and optical properties on vacuum annealing. The films deposited from Mo or Ta boats possessed distinctly different properties. The Mo-boat evaporated pristine films were amorphous, transparent (α ∼ 10 3  cm −1 ) in visible region and had a direct band gap of about 3.2 eV. Vacuum annealing at 723 K brought about their crystallization predominantly into cubic γ-Ga 2 S 3 and a blue shift by about 0.2 eV. The Ta-boat evaporated pristine films were also amorphous but were absorbing (α ∼ 10 4  cm −1 ) and had a direct band gap of about 2.1 eV. These crystallized into hexagonal GaS and experienced a blue shift by more than 1.0 eV on vacuum annealing at 723 K. The dissimilar properties of the two kinds of films arose mainly from their different atomic compositions. The Mo-boat evaporated pristine films contained Ga and S in ∼1:1 atomic proportions while those prepared using Ta-boat were Ga rich which impaired their transmission characteristics. The former composition favoured the stabilization of S rich gallium sulphide (Ga 2 S 3 ) phase while the latter stabilised S deficient species, GaS. Besides inducing crystallization, vacuum annealing at 723 K also caused the diffusion of Ga in excess of atomic composition of the phase formed, into soda-lime glass which improved the optical transmission of the films. Gallium oxyhydroxide, an inevitable co-product of the chemical synthetic process, in the evaporant introduced oxygen and hydrogen impurities in the films which do not seem to significantly influence their optical properties. - Highlights: • Gallium sulphide films are prepared by thermal evaporation from a Mo or Ta boat. • Mo-boat prepared pristine film has Ga

  2. A systematic study of odd-odd Gallium nuclei

    International Nuclear Information System (INIS)

    Allegro, P.R.P.; Medina, N.H.; Oliveira, J.R.B.; Ribas, R.V.; Cybulska, E.W.; Seale, W.A.; Zagatto, V.A.B.; Zahn, G.S.; Genezini, F.A.; Silveira, M.A.G.; Tabor, S.; Bender, P.; Tripathi, V.; Baby, L.

    2012-01-01

    Full text: Recently, many studies have been published attempting to explain the role of the 0g 9/2 orbital in the high spin excited states of nuclei in the region of the mass A=50-80, especially very neutron rich nuclei like, for example 59-66 Fe [1], 65,67 Cu [2], 70,80 Ge [3,4] nuclei and those with odd mass number like As, Ge and Ga [5]. Stefanescu et al. [6] demonstrated the presence of bands in the neutron-rich isotopes Ga formed from excitation of a proton to the 0g 9/2 orbital and Cheal et al. [7] revealed, from the study of the spins and moments of the ground state, changes in nuclear structure of the odd Ga isotopes between N = 40 and N 50, indicating a change in the energy gap between the 0g 9/2 orbital and the pf shell. In this work, we have performed a systematic study of odd-odd 64,66,68,70 Ga nuclei to examine the behavior of the 0g 9/2 orbital with an increasing number of neutrons. We have compared the predictions of the Large Scale Shell Model, obtained using the Antoine code [8] with the FPG [9] and JUN45 [10] effective interactions, with the experimental results obtained with in-beam gamma-ray spectroscopy experiments performed at University of Sao Paulo using SACI-PERERE spectrometer and at Florida State University using the Clover Array System. We have also performed calculations to study 67 Ge, an odd nucleus in the same mass region, in order to verify the behavior of the effective interactions in a nucleus without the proton-neutron interaction. [1] S. Lunardi. et al., Phys. Rev. C 76, 034303 (2007). [2] C. J. Chiara et al., Phys. Rev. C 85, 024309 (2012). [3] M. Sugawara et al., Phys. Rev. C 81, 024309 (2010). [4] H. Iwasaki.et al., Phys. Rev. C 78, 021304(R) (2008). [5] N. Yoshinaga et al. Phys. Rev. C 78, 044320 (2008). [6] I. Stefanescu et al., Phys. Rev. C 79, 064302 (2009). [7] B. Cheal et al. Phys. Rev. Lett. 104, 252502 (2010). [8] E. Caurier and F. Nowacki, Acta Phys. Polonica B 30, 705 (1999). [9] O. Sorlin et al., Phys. Rev. Lett

  3. Group 13 β-ketoiminate compounds: gallium hydride derivatives as molecular precursors to thin films of Ga2O3.

    Science.gov (United States)

    Pugh, David; Marchand, Peter; Parkin, Ivan P; Carmalt, Claire J

    2012-06-04

    Bis(β-ketoimine) ligands, [R{N(H)C(Me)-CHC(Me)═O}(2)] (L(1)H(2), R = (CH(2))(2); L(2)H(2), R = (CH(2))(3)), linked by ethylene (L(1)) and propylene (L(2)) bridges have been used to form aluminum, gallium, and indium chloride complexes [Al(L(1))Cl] (3), [Ga(L(n))Cl] (4, n = 1; 6, n = 2) and [In(L(n))Cl] (5, n = 1; 7, n = 2). Ligand L(1) has also been used to form a gallium hydride derivative [Ga(L(1))H] (8), but indium analogues could not be made. β-ketoimine ligands, [Me(2)N(CH(2))(3)N(H)C(R')-CHC(R')═O] (L(3)H, R' = Me; L(4)H, R' = Ph), with a donor-functionalized Lewis base have also been synthesized and used to form gallium and indium alkyl complexes, [Ga(L(3))Me(2)] (9) and [In(L(3))Me(2)] (10), which were isolated as oils. The related gallium hydride complexes, [Ga(L(n))H(2)] (11, n = 3; 12, n = 4), were also prepared, but again no indium hydride species could be made. The complexes were characterized mainly by NMR spectroscopy, mass spectrometry, and single crystal X-ray diffraction. The β-ketoiminate gallium hydride compounds (8 and 11) have been used as single-source precursors for the deposition of Ga(2)O(3) by aerosol-assisted (AA)CVD with toluene as the solvent. The quality of the films varied according to the precursor used, with the complex [Ga(L(1))H] (8) giving by far the best quality films. Although the films were amorphous as deposited, they could be annealed at 1000 °C to form crystalline Ga(2)O(3). The films were analyzed by powder XRD, SEM, and EDX.

  4. Solar neutrino and 51Cr results from SAGE

    International Nuclear Information System (INIS)

    Gavrin, V.N.; Abdurashitov, J.N.; Girin, S.V.

    1997-01-01

    The Russian-American solar neutrino Experiment (SAGE) has carried out measurements of the capture rate of solar neutrinos on metallic gallium in a radiochemical experiment at the Baksan Neutrino Observatory during the period January 1990 to December 1994. The measured capture rate on 71 Ga is 72+12/-10 (stat) +5/-7 (syst) SNU. This represents only 53-59 % of the predicted Standard Solar Model (SSM) rates. Taken together with the measurements of the other solar neutrino experiments, this deficit would appear to be best interpreted as due to Mikheyev-Smirnov-Wolfenstein neutrino oscillations. A measurement of the production rate of 71 Ge by an intense 51 Cr source to test the overall operation of the experiment showed the extraction efficiency was 0.95 ± 0.11 (stat) +0.05/-0.08 (syst), indicating that the experiment is operating as expected. (orig.)

  5. Russian-American Security Cooperation After St. Petersburg: Challenges and Opportunities

    Science.gov (United States)

    2007-04-01

    each shipment. The third GTRI element, the Reduced Enrichment for Research and Test Reactors ( RERTR ) program, funds efforts to convert the cores of...IAEA in the Russian Research Reactor Return Pro- gram, the RERTR Program, and the Tripartite Initia- tive to secure high-risk radioactive sources...Russia’s involvement in the RERTR , see Charles D. Ferguson, Preventing Catastrophic Nuclear Terrorism, New York: Council on Foreign Relations, March 2006

  6. Fostering Cross-Cultural Understanding Through E-Learning: Russian-American Forum Case-Study.

    Directory of Open Access Journals (Sweden)

    Ekaterina V. Talalakina

    2010-09-01

    Full Text Available Abstract— The importance of cross-cultural understanding is accelerated nowadays by globalization and joint efforts of different countries in the face of global challenges. Countries’ educational systems display attempts to incorporate cross-cultural studies in their curricula across all stages of formal learning. Many higher education institutions offer special courses aimed at promoting cross-cultural studies. One of the tools used to facilitate the process is e-learning. The present article examines the case study of an internet-based collaboration between two higher education institutions – State University Higher School of Economics in Russia and Champlain College in the USA – in fostering cross-cultural understanding. The project is based on the study of individualistic and collectivistic values within the framework of two corresponding courses studied at both institutions. The topicality of the study is determined by the growing importance of the cooperation of two countries on the international affairs arena, on the one hand, and the fundamental differences of the countries’ underlying value system, on the other. In particular, a post-soviet Russia is generally viewed as a developing democracy representing the collectivistic end of the value spectrum, whereas the USA is considered as an extreme case of individualistic value system. The comparison and contrast of the two systems conducted simultaneously by the representatives of both cultures (students of the two universities within a specifically built internet forum comprises the base of the project. The case study covers the project’s objectives, its background, the rationale behind its content choice, the design of the e-learning tool, the profile of the participants of the project, its implementation stages and its outcome. The major findings of the case study deal with the process of building cross-cultural awareness, reinforcing students’ analytical skills and providing them with a research incentive, fostering self-reflection, values projection from one culture onto the other, drawing the areas of their intersection, which, finally, result in cross-cultural understanding. The results of the study are assessed at quantative and qualitative levels.

  7. Proceedings of the 5. joint Russian-American computational mathematics conference

    International Nuclear Information System (INIS)

    1997-01-01

    These proceedings contain a record of the talks presented and papers submitted by participants. The conference participants represented three institutions from the United States, Sandia National Laboratories (SNL), Los Alamos National Laboratory (LANL), Lawrence Livermore National Laboratory (LLNL), and two from Russia, Russian Federal Nuclear Center--All Russian Research Institute of Experimental Physics (RFNC-VNIIEF/Arzamas-16), and Russian Federal Nuclear Center--All Russian Research Institute of Technical Physics (RFNC-VNIITF/Chelyabinsk-70). The presentations and papers cover a wide range of applications from radiation transport to materials. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database

  8. Russian-American strategy for stabilization and immobilization of excess Russian weapons origin plutonium

    International Nuclear Information System (INIS)

    Jardine, L.J.; Borisov, G.B.

    1998-01-01

    In the US, impure Pu-containing materials such as residues and scrapes are in storage, in known quantities, and in materials of various compositions with known Pu contents. However, in Russia, there are no substantial quantities of accumulated impure Pu-containing materials awaiting processing either for disposition or for transuranic (TRU) geologic disposal as there are in the Us. during the Cold War, the Russian approach to Pu processing for weapons production was different from that of the US. All impure Pu- containing materials were routinely reprocessed, and the residual Pu was recovered and purified for reuse until residual Pu levels of less than 200 mg/kg (less than 200 ppm) in any discharged solid process waste streams were reached. Wastes containing less than 200 ppm Pu were routinely discharged for burial in cement waste forms. Russia is studying changing from this practice of recovery of impure Pu for reuse to immobilizing future impure Pu-containing materials into solids at higher concentrations of Pu than 200 ppm for eventual geologic disposal

  9. Proceedings of the 5. joint Russian-American computational mathematics conference

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    These proceedings contain a record of the talks presented and papers submitted by participants. The conference participants represented three institutions from the United States, Sandia National Laboratories (SNL), Los Alamos National Laboratory (LANL), Lawrence Livermore National Laboratory (LLNL), and two from Russia, Russian Federal Nuclear Center--All Russian Research Institute of Experimental Physics (RFNC-VNIIEF/Arzamas-16), and Russian Federal Nuclear Center--All Russian Research Institute of Technical Physics (RFNC-VNIITF/Chelyabinsk-70). The presentations and papers cover a wide range of applications from radiation transport to materials. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

  10. Facial osteomyelitis as complication of chronic sinusitis in hemophiliac-AIDS patients - scintigraphic evaluation with technetium-99m-MDP and Gallium-67

    International Nuclear Information System (INIS)

    Marques, Marise da Penha Costa; Wolosker, Sara; Marchiori, Edson

    1997-01-01

    In the paper six cases of facial osteomyelitis as a complication of chronic sinusitis in hemophiliac-AIDS patients are reported. Osteomyelitis was suggested by an increasing of erythrocyte sedimentation rate. The diagnosis was confirmed by a positive 99m Tc MDP scintigraphy. The patients were submitted to clinical treatment. The erythrocyte sedimentation rate and 67-gallium citrate scans were used in the follow-up of the therapy. Three patients had negative gallium after three weeks of organism-specific antibiotic therapy; in two patients the gallium scintigraphy remained positive. One patient did not undergo the radionuclide scan for this clinical conditions. These results suggest that MDP scans showed higher sensitivity and specificity in detection of bone disease in chronic sinusitis. Gallium scans appeared to be valuable tool in the follow-up of the infection. There are no reports in the literature of osteomyelitis as a complication of chronic sinusitis in AIDS patient. (author)

  11. ISTTOK tokamak plasmas influence on a liquid gallium jet dynamic behavior

    International Nuclear Information System (INIS)

    Gomes, R.B.; Silva, C.; Fernandes, H.; Duarte, P.; Nedzelskiy, I.; Lielausis, O.; Klyukin, A.; Platacis, E.

    2011-01-01

    The main concern in using free flowing liquid metals in fusion devices is related to their interaction with magnetic fields. On ISTTOK tokamak, liquid gallium jets are injected deep into the plasma along a vertical direction. The influence of the plasma interaction on the jet has been investigated monitoring the liquid metal behavior using a fast frame camera. A radial shift on its trajectory has been detected and found to depend on the toroidal magnetic field magnitude and principally on the plasma position within the chamber. The analysis performed to understand the dynamics of the jet perturbation by the plasma is presented in this paper. The jet surface temperature increase during this interaction has also been measured, using absolutely calibrated multichannel IR sensors, to evaluate the jet power exhaustion capability.

  12. ISTTOK tokamak plasmas influence on a liquid gallium jet dynamic behavior

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, R.B., E-mail: gomes@ipfn.ist.utl.pt [Associacao EURATOM/IST, Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, 1049-001 Lisboa (Portugal); Silva, C.; Fernandes, H.; Duarte, P.; Nedzelskiy, I. [Associacao EURATOM/IST, Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, 1049-001 Lisboa (Portugal); Lielausis, O.; Klyukin, A.; Platacis, E. [Association EURATOM/University of Latvia, Institute of Solid State Physics, 8 Kengaraga Str., LV-1063 Riga (Latvia)

    2011-08-01

    The main concern in using free flowing liquid metals in fusion devices is related to their interaction with magnetic fields. On ISTTOK tokamak, liquid gallium jets are injected deep into the plasma along a vertical direction. The influence of the plasma interaction on the jet has been investigated monitoring the liquid metal behavior using a fast frame camera. A radial shift on its trajectory has been detected and found to depend on the toroidal magnetic field magnitude and principally on the plasma position within the chamber. The analysis performed to understand the dynamics of the jet perturbation by the plasma is presented in this paper. The jet surface temperature increase during this interaction has also been measured, using absolutely calibrated multichannel IR sensors, to evaluate the jet power exhaustion capability.

  13. Imaging the p-n junction in a gallium nitride nanowire with a scanning microwave microscope

    Energy Technology Data Exchange (ETDEWEB)

    Imtiaz, Atif [Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305 (United States); Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, Colorado 80309 (United States); Wallis, Thomas M.; Brubaker, Matt D.; Blanchard, Paul T.; Bertness, Kris A.; Sanford, Norman A.; Kabos, Pavel, E-mail: kabos@boulder.nist.gov [Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305 (United States); Weber, Joel C. [Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305 (United States); Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309 (United States); Coakley, Kevin J. [Information Technology Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305 (United States)

    2014-06-30

    We used a broadband, atomic-force-microscope-based, scanning microwave microscope (SMM) to probe the axial dependence of the charge depletion in a p-n junction within a gallium nitride nanowire (NW). SMM enables the visualization of the p-n junction location without the need to make patterned electrical contacts to the NW. Spatially resolved measurements of S{sub 11}{sup ′}, which is the derivative of the RF reflection coefficient S{sub 11} with respect to voltage, varied strongly when probing axially along the NW and across the p-n junction. The axial variation in S{sub 11}{sup ′}  effectively mapped the asymmetric depletion arising from the doping concentrations on either side of the junction. Furthermore, variation of the probe tip voltage altered the apparent extent of features associated with the p-n junction in S{sub 11}{sup ′} images.

  14. Nanoscale footprints of self-running gallium droplets on GaAs surface.

    Directory of Open Access Journals (Sweden)

    Jiang Wu

    Full Text Available In this work, the nanoscale footprints of self-driven liquid gallium droplet movement on a GaAs (001 surface will be presented and analyzed. The nanoscale footprints of a primary droplet trail and ordered secondary droplets along primary droplet trails are observed on the GaAs surface. A well ordered nanoterrace from the trail is left behind by a running droplet. In addition, collision events between two running droplets are investigated. The exposed fresh surface after a collision demonstrates a superior evaporation property. Based on the observation of droplet evolution at different stages as well as nanoscale footprints, a schematic diagram of droplet evolution is outlined in an attempt to understand the phenomenon of stick-slip droplet motion on the GaAs surface. The present study adds another piece of work to obtain the physical picture of a stick-slip self-driven mechanism in nanoscale, bridging nano and micro systems.

  15. Study of relaxation processes and uniaxial anisotropy in the Europium Gallium Garnet epitaxial films

    International Nuclear Information System (INIS)

    Mukhopadhyay, P.

    1987-04-01

    We report here the magnetic properties of Europium-Gallium Garnet LPE films of the type Eu x Y 3-x Fe 5-y Ga y O 12 (where O< x<1.2 and 1< y<1.1). The mechanism by which the magnetic moments relax in Eu or Sm Garnets is still not fully understood. We have made studies on Eu-Ga garnet films and explain some of the results observed in these films. Pb and Pt ions are always found as impurities in our films. Pb ions contribute to the anisotropy in the film. Most of the experimental results can be explained with the three sub lattice model. The shape of the FMR line width shows strong sensitivity towards the surface impurities. (author). 18 refs, 6 figs, 1 tab

  16. Damage structure of gallium arsenide irradiated in a high-voltage electron microscope

    International Nuclear Information System (INIS)

    Loretto, D.; Loretto, M.H.

    1989-01-01

    Semi-insulating undoped gallium arsenide has been irradiated in a high-voltage electron microscope between room temperature and about 500 0 C for doses of up to 5 x 10 22 electrons cm -2 at 1 MeV. Room-temperature irradiation produces small (less than 5 nm) damage clusters. As the temperature of the irradiation is increased, the size of these clusters increases, until at about 300 0 C a high density of dislocation loops can be resolved. The dislocation loops, 20 nm or less in diameter, which are produced at about 500 0 C have been analysed in a bright field using a two-beam inside-outside method which minimises the tilt necessary between micrographs. It is concluded that the loops are an interstitial perfect-edge type with a Burgers vector of (a/2) . (author)

  17. Magnetic properties of Kramers rare earth ions in aluminium and gallium garnets

    International Nuclear Information System (INIS)

    Capel, H.

    1964-01-01

    The magnetic properties of Kramers rare earth ions in aluminium and gallium garnets (MAlG and MGaG) are discussed by means of a molecular field treatment. The symmetry properties of the space group permit to establish a parametrization for the magnetic dipolar and exchange couplings. The magnetic properties of the system can be expressed in terms of these parameters and the g factors of the rare earth ions. We have calculated the transition temperatures, the sub-lattice magnetizations, the susceptibility in the paramagnetic region and the antiferromagnetic susceptibility for a special type of magnetic ordering. The influence of the excited Kramers doublets is described by means of a generalization of the usual g tensor. (authors) [fr

  18. Radiation damage in gallium-stabilized δ-plutonium with helium bubbles

    Energy Technology Data Exchange (ETDEWEB)

    Wu, FengChao [CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230027 (China); Wang, Pei [Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Liu, XiaoYi [CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230027 (China); Wu, HengAn, E-mail: wuha@ustc.edu.cn [CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230027 (China)

    2017-02-15

    To understand the role of helium on self-irradiation effects in δ-plutonium, microstructure evolutions due to α-decay events near pre-existing helium bubbles in gallium-stabilized δ-plutonium are investigated using molecular dynamics simulations. Bubble promoting effect plays a dominating role in point defects production, resulting in increasing number of point defects. When lightweight helium atoms act as media, energy transfer discrepancy and altered spatial morphology of point defects induced by mass effect are revealed. The evolution of stacking faults surrounding the disordered core is studied and their binding effect on the propagation of point defects are presented. The cascade-induced bubble coalescence, resolution and re-nucleation driven by internal pressure are obtained in the investigation on helium behaviors. The intrinsic tendency in our simulated self-irradiation with helium bubbles is significant for understanding the underlying mechanism of aging in plutonium and its alloys.

  19. Optoelectronic and low temperature thermoelectric studies on nanostructured thin films of silver gallium selenide

    International Nuclear Information System (INIS)

    Jacob, Rajani; Philip, Rachel Reena; Nazer, Sheeba; Abraham, Anitha; Nair, Sinitha B.; Pradeep, B.; Urmila, K. S.; Okram, G. S.

    2014-01-01

    Polycrystalline thin films of silver gallium selenide were deposited on ultrasonically cleaned soda lime glass substrates by multi-source vacuum co-evaporation technique. The structural analysis done by X-ray diffraction ascertained the formation of nano structured tetragonal chalcopyrite thin films. The compound formation was confirmed by X-ray photo-electron spectroscopy. Atomic force microscopic technique has been used for surface morphological analysis. Direct allowed band gap ∼1.78eV with high absorption coefficient ∼10 6 /m was estimated from absorbance spectra. Low temperature thermoelectric effects has been investigated in the temperature range 80–330K which manifested an unusual increase in Seebeck coefficient with negligible phonon drag toward the very low and room temperature regime. The electrical resistivity of these n-type films was assessed to be ∼2.6Ωm and the films showed good photo response

  20. Optoelectronic and low temperature thermoelectric studies on nanostructured thin films of silver gallium selenide

    Science.gov (United States)

    Jacob, Rajani; Philip, Rachel Reena; Nazer, Sheeba; Abraham, Anitha; Nair, Sinitha B.; Pradeep, B.; Urmila, K. S.; Okram, G. S.

    2014-01-01

    Polycrystalline thin films of silver gallium selenide were deposited on ultrasonically cleaned soda lime glass substrates by multi-source vacuum co-evaporation technique. The structural analysis done by X-ray diffraction ascertained the formation of nano structured tetragonal chalcopyrite thin films. The compound formation was confirmed by X-ray photo-electron spectroscopy. Atomic force microscopic technique has been used for surface morphological analysis. Direct allowed band gap ˜1.78eV with high absorption coefficient ˜106/m was estimated from absorbance spectra. Low temperature thermoelectric effects has been investigated in the temperature range 80-330K which manifested an unusual increase in Seebeck coefficient with negligible phonon drag toward the very low and room temperature regime. The electrical resistivity of these n-type films was assessed to be ˜2.6Ωm and the films showed good photo response.

  1. Boundary layers in turbulent convection for air, liquid gallium and liquid sodium

    Science.gov (United States)

    Scheel, Janet; Schumacher, Joerg

    2017-11-01

    The scaling of physical quantities that characterize the shape and dynamics of the viscous and thermal boundary layers with respect to the Rayleigh number will be presented for three series of three-dimensional high-resolution direct numerical simulations of Rayleigh-Benard convection (RBC) in a closed cylindrical cell of aspect ratio one. The simulations have been conducted for convection in air at a Prandtl number Pr = 0.7, in liquid gallium at Pr = 0.021 and in liquid sodium at Pr = 0.005. Then we discuss three statistical analysis methods which have been developed to predict the transition of turbulent RBC into the ultimate regime. The methods are based on the large-scale properties of the velocity profile. All three methods indicate that the range of critical Rayleigh numbers is shifted to smaller magnitudes as the Prandtl number becomes smaller. This work is supported by the Priority Programme SPP 1881 of the Deutsche Forschungsgemeinschaft.

  2. Characterization of silver-gallium nanowires for force and mass sensing applications

    International Nuclear Information System (INIS)

    Biedermann, Laura B; Reifenberger, Ronald G; Tung, Ryan C; Raman, Arvind; Yazdanpanah, Mehdi M; Cohn, Robert W

    2010-01-01

    We investigate the mechanical properties of cantilevered silver-gallium (Ag 2 Ga) nanowires using laser Doppler vibrometry. From measurements of the resonant frequencies and associated operating deflection shapes, we demonstrate that these Ag 2 Ga nanowires behave as ideal Euler-Bernoulli beams. Furthermore, radial asymmetries in these nanowires are detected through high resolution measurements of the vibration spectra. These crystalline nanowires possess many ideal characteristics for nanoscale force and mass sensing, including small spring constants (as low as 10 -4 N m -1 ), high frequency bandwidth with resonance frequencies in the 0.02-10 MHz range, small suspended mass (picograms), and relatively high Q-factors (∼2-50) under ambient conditions. We evaluate the utility of Ag 2 Ga nanowires for nanocantilever applications, including ultrasmall mass and high frequency bandwidth piconewton force detection.

  3. Spin polarized first principles study of Mn doped gallium nitride monolayer nanosheet

    Science.gov (United States)

    Sharma, Venus; Kaur, Sumandeep; Srivastava, Sunita; Kumar, Tankeshwar

    2017-05-01

    The structural, electronic and magnetic properties of gallium nitride nanosheet (GaNs) doped with Mn atoms have been studied using spin polarized density functional theory. The binding energy per atom, Energy Band gap, Fermi energy, magnetic moment, electric dipole moment have been found. The doped nanosheet is found to be more stable than pure GaN monolayer nanosheet. Adsorption of Mn atom has been done at four different sites on GaNs which affects the fermi level position. It is found that depending on the doping site, Mn can behave both like p-type semiconductor and also as n-type semiconductor. Also, it is ascertained that Mn doped GaNs (GaNs-Mn) exhibits ferromagnetic behavior.

  4. Two-dimensional dopant profiling of gallium nitride p-n junctions by scanning capacitance microscopy

    Science.gov (United States)

    Lamhamdi, M.; Cayrel, F.; Frayssinet, E.; Bazin, A. E.; Yvon, A.; Collard, E.; Cordier, Y.; Alquier, D.

    2016-04-01

    Two-dimensional imaging of dopant profiles for n and p-type regions are relevant for the development of new power semiconductors, especially for gallium nitride (GaN) for which classical profiling techniques are not adapted. This is a challenging task since it needs a technique with simultaneously good sensitivity, high spatial resolution and high dopant gradient resolution. To face these challenges, scanning capacitance microscopy combined with Atomic Force Microscopy is a good candidate, presenting reproducible results, as demonstrated in literature. In this work, we attempt to distinguish reliably and qualitatively the various doping concentrations and type at p-n and unipolar junctions. For both p-n and unipolar junctions three kinds of samples were prepared and measured separately. The space-charge region of the p-n metallurgical junction, giving rise to different contrasts under SCM imaging, is clearly observed, enlightening the interest of the SCM technique.

  5. Simultaneous specimen current and time-dependent cathodoluminescence measurements on gallium nitride

    Energy Technology Data Exchange (ETDEWEB)

    Campo, E. M., E-mail: e.campo@bangor.ac.uk; Hopkins, L. [School of Electronic Engineering, Bangor University, Gwynedd LL57 1UT (United Kingdom); Pophristic, M. [Department of Chemistry and Biochemistry, University of the Science, Philadelphia, Pennsylvania 19104 (United States); Ferguson, I. T. [Department of Electrical and Computer Engineering, Missouri University of Science and Technology, Rolla, Missouri 65409 (United States)

    2016-06-28

    Time-dependent cathodoluminescence (CL) and specimen current (SC) are monitored to evaluate trapping behavior and evolution of charge storage. Examination of CL and SC suggests that the near band edge emission in GaN is reduced primarily by the activation of traps upon irradiation, and Gallium vacancies are prime candidates. At the steady state, measurement of the stored charge by empiric-analytical methods suggests that all available traps within the interaction volume have been filled, and that additional charge is being stored interstitially, necessarily beyond the interaction volume. Once established, the space charge region is responsible for the steady state CL emission and, prior to build up, it is responsible for the generation of diffusion currents. Since the non-recombination effects resulting from diffusion currents that develop early on are analogous to those leading to device failure upon aging, this study is fundamental toward a holistic insight into optical properties in GaN.

  6. Instability of Yb3+ and Pr3+ low-symmetry luminescence centers in gallium phosphide

    International Nuclear Information System (INIS)

    Kasatkin, V.A.

    1985-01-01

    The stability of γb 3+ and Pr 3+ low-symmetry luminescence centers formed in gallium phosphide during quenching were studied in the process of durable storage and annealing. Observation of the Yb 3+ and Pr 3+ centrer states was accomplished by the photoluminescence spectra at 18 K. It has been established that annealing in the dark under normal conditions results in a reduced integral luminescence intensity of all low-symmetry Yb 3+ and Pr 3+ centers. Annealing of quenched GaP and GaP saples at 400 K results in complete disappearance of intracenter luminescence of Pr 3+ and low-symmetry Yb 3+ centers. Decomposition during storage and low anealing temperature point to the instability of low-symmetry centers of Pr 3+ and Yb 3+ luminescence

  7. Origin of deep subgap states in amorphous indium gallium zinc oxide: Chemically disordered coordination of oxygen

    International Nuclear Information System (INIS)

    Sallis, S.; Williams, D. S.; Butler, K. T.; Walsh, A.; Quackenbush, N. F.; Junda, M.; Podraza, N. J.; Fischer, D. A.; Woicik, J. C.; White, B. E.; Piper, L. F. J.

    2014-01-01

    The origin of the deep subgap states in amorphous indium gallium zinc oxide (a-IGZO), whether intrinsic to the amorphous structure or not, has serious implications for the development of p-type transparent amorphous oxide semiconductors. We report that the deep subgap feature in a-IGZO originates from local variations in the oxygen coordination and not from oxygen vacancies. This is shown by the positive correlation between oxygen composition and subgap intensity as observed with X-ray photoelectron spectroscopy. We also demonstrate that the subgap feature is not intrinsic to the amorphous phase because the deep subgap feature can be removed by low-temperature annealing in a reducing environment. Atomistic calculations of a-IGZO reveal that the subgap state originates from certain oxygen environments associated with the disorder. Specifically, the subgap states originate from oxygen environments with a lower coordination number and/or a larger metal-oxygen separation.

  8. Deep subgap feature in amorphous indium gallium zinc oxide: Evidence against reduced indium

    International Nuclear Information System (INIS)

    Sallis, Shawn; Williams, Deborah S.; Quackenbush, Nicholas F.; Senger, Mikell; Woicik, Joseph C.; White, Bruce E.; Piper, Louis F.J.

    2015-01-01

    Amorphous indium gallium zinc oxide (a-IGZO) is the archetypal transparent amorphous oxide semiconductor. Despite the gains made with a-IGZO over amorphous silicon in the last decade, the presence of deep subgap states in a-IGZO active layers facilitate instabilities in thin film transistor properties under negative bias illumination stress. Several candidates could contribute to the formation of states within the band gap. Here, we present evidence against In + lone pair active electrons as the origin of the deep subgap features. No In + species are observed, only In 0 nano-crystallites under certain oxygen deficient growth conditions. Our results further support under coordinated oxygen as the source of the deep subgap states. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Origin of deep subgap states in amorphous indium gallium zinc oxide: Chemically disordered coordination of oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Sallis, S.; Williams, D. S. [Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States); Butler, K. T.; Walsh, A. [Center for Sustainable Technologies and Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Quackenbush, N. F. [Department of Physics, Applied Physics, and Astronomy, Binghamton University, Binghamton, New York 13902 (United States); Junda, M.; Podraza, N. J. [Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606 (United States); Fischer, D. A.; Woicik, J. C. [Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); White, B. E.; Piper, L. F. J., E-mail: lpiper@binghamton.edu [Department of Physics, Applied Physics, and Astronomy, Binghamton University, Binghamton, New York 13902 (United States); Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States)

    2014-06-09

    The origin of the deep subgap states in amorphous indium gallium zinc oxide (a-IGZO), whether intrinsic to the amorphous structure or not, has serious implications for the development of p-type transparent amorphous oxide semiconductors. We report that the deep subgap feature in a-IGZO originates from local variations in the oxygen coordination and not from oxygen vacancies. This is shown by the positive correlation between oxygen composition and subgap intensity as observed with X-ray photoelectron spectroscopy. We also demonstrate that the subgap feature is not intrinsic to the amorphous phase because the deep subgap feature can be removed by low-temperature annealing in a reducing environment. Atomistic calculations of a-IGZO reveal that the subgap state originates from certain oxygen environments associated with the disorder. Specifically, the subgap states originate from oxygen environments with a lower coordination number and/or a larger metal-oxygen separation.

  10. Electrical effect of titanium diffusion on amorphous indium gallium zinc oxide

    International Nuclear Information System (INIS)

    Choi, Seung-Ha; Jung, Woo-Shik; Park, Jin-Hong

    2012-01-01

    In this work, thermal diffusion phenomenon of Ti into amorphous indium gallium zinc oxide (α-IGZO) was carefully investigated with secondary ion mass spectroscopy, I-V, and R s measurement systems and HSC chemistry simulation tool. According to the experimental and simulated results, the diffused Ti atoms were easily oxidized due to its lowest oxidation free energy. Since oxygen atoms were decomposed from the α-IGZO during the oxidation of Ti, the number of oxygen vacancies working as electron-donating sites in α-IGZO was dramatically increased, contributing to the decrease of resistivity (ρ) from 1.96 Ω cm (as-deposited α-IGZO) to 1.33 × 10 −3 Ω cm (350 °C annealed α-IGZO).

  11. Deep subgap feature in amorphous indium gallium zinc oxide: Evidence against reduced indium

    Energy Technology Data Exchange (ETDEWEB)

    Sallis, Shawn; Williams, Deborah S. [Materials Science and Engineering, Binghamton University, Binghamton, New York, 13902 (United States); Quackenbush, Nicholas F.; Senger, Mikell [Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, New York, 13902 (United States); Woicik, Joseph C. [Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland, 20899 (United States); White, Bruce E.; Piper, Louis F.J. [Materials Science and Engineering, Binghamton University, Binghamton, New York, 13902 (United States); Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, New York, 13902 (United States)

    2015-07-15

    Amorphous indium gallium zinc oxide (a-IGZO) is the archetypal transparent amorphous oxide semiconductor. Despite the gains made with a-IGZO over amorphous silicon in the last decade, the presence of deep subgap states in a-IGZO active layers facilitate instabilities in thin film transistor properties under negative bias illumination stress. Several candidates could contribute to the formation of states within the band gap. Here, we present evidence against In{sup +} lone pair active electrons as the origin of the deep subgap features. No In{sup +} species are observed, only In{sup 0} nano-crystallites under certain oxygen deficient growth conditions. Our results further support under coordinated oxygen as the source of the deep subgap states. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Water-soluble thin film transistors and circuits based on amorphous indium-gallium-zinc oxide.

    Science.gov (United States)

    Jin, Sung Hun; Kang, Seung-Kyun; Cho, In-Tak; Han, Sang Youn; Chung, Ha Uk; Lee, Dong Joon; Shin, Jongmin; Baek, Geun Woo; Kim, Tae-il; Lee, Jong-Ho; Rogers, John A

    2015-04-22

    This paper presents device designs, circuit demonstrations, and dissolution kinetics for amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistors (TFTs) comprised completely of water-soluble materials, including SiNx, SiOx, molybdenum, and poly(vinyl alcohol) (PVA). Collections of these types of physically transient a-IGZO TFTs and 5-stage ring oscillators (ROs), constructed with them, show field effect mobilities (∼10 cm2/Vs), on/off ratios (∼2×10(6)), subthreshold slopes (∼220 mV/dec), Ohmic contact properties, and oscillation frequency of 5.67 kHz at supply voltages of 19 V, all comparable to otherwise similar devices constructed in conventional ways with standard, nontransient materials. Studies of dissolution kinetics for a-IGZO films in deionized water, bovine serum, and phosphate buffer saline solution provide data of relevance for the potential use of these materials and this technology in temporary biomedical implants.

  13. The crystal structure and twinning of neodymium gallium perovskite single crystals

    International Nuclear Information System (INIS)

    Ubizskii, S.B.; Vasylechko, L.O.; Savytskii, D.I.; Matkovskii, A.O.; Syvorotka, I.M.

    1994-01-01

    By means of X-ray structure analysis, the crystal structure of neodymium gallium perovskite (NGP) single crystals (NdGaO 3 ) being used as a substrate for HTSC film epitaxy has been refined and the position of atoms has been determined. The possibility of YBa 2 Cu 3 O 7-x film epitaxy on the plane (110) of NGP crystal as well as its advantages and pitfalls are analysed from structural data. The twinning types in the NGP crystal were established. The twinning structure of NGP substrates is found to be stable up to a temperature of 1173 K, as differentiated from the LaGaO 3 and LaAlO 3 substrates. It is intimated that the twinning in the NGP substrates oriented as (001) can result in creation of 90 degrees twin bonds in a film, and in the case of (110)-oriented plates it is possible to ignore the twinning presence in substrate completely. (author)

  14. Two-dimensional dopant profiling of gallium nitride p–n junctions by scanning capacitance microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lamhamdi, M. [GREMAN UMR 7347-Université de Tours, 10 Rue Thales de Milet, BP 7155, 37071 Tours (France); Ecole national des sciences appliquées khouribga, Université Hassan 1er, 26000 Settat (Morocco); Cayrel, F. [GREMAN UMR 7347-Université de Tours, 10 Rue Thales de Milet, BP 7155, 37071 Tours (France); Frayssinet, E. [CRHEA-CNRS, Rue Bernard Grégory, Sophia Antipolis, 06560 Valbonne (France); Bazin, A.E.; Yvon, A.; Collard, E. [STMicroelectronics, 16 Rue Pierre et Marie Curie, BP 7155, 37071 Tours (France); Cordier, Y. [CRHEA-CNRS, Rue Bernard Grégory, Sophia Antipolis, 06560 Valbonne (France); Alquier, D. [GREMAN UMR 7347-Université de Tours, 10 Rue Thales de Milet, BP 7155, 37071 Tours (France)

    2016-04-01

    Two-dimensional imaging of dopant profiles for n and p-type regions are relevant for the development of new power semiconductors, especially for gallium nitride (GaN) for which classical profiling techniques are not adapted. This is a challenging task since it needs a technique with simultaneously good sensitivity, high spatial resolution and high dopant gradient resolution. To face these challenges, scanning capacitance microscopy combined with Atomic Force Microscopy is a good candidate, presenting reproducible results, as demonstrated in literature. In this work, we attempt to distinguish reliably and qualitatively the various doping concentrations and type at p–n and unipolar junctions. For both p–n and unipolar junctions three kinds of samples were prepared and measured separately. The space-charge region of the p–n metallurgical junction, giving rise to different contrasts under SCM imaging, is clearly observed, enlightening the interest of the SCM technique.

  15. Advances in gallium arsenide monolithic microwave integrated-circuit technology for space communications systems

    Science.gov (United States)

    Bhasin, K. B.; Connolly, D. J.

    1986-01-01

    Future communications satellites are likely to use gallium arsenide (GaAs) monolithic microwave integrated-circuit (MMIC) technology in most, if not all, communications payload subsystems. Multiple-scanning-beam antenna systems are expected to use GaAs MMIC's to increase functional capability, to reduce volume, weight, and cost, and to greatly improve system reliability. RF and IF matrix switch technology based on GaAs MMIC's is also being developed for these reasons. MMIC technology, including gigabit-rate GaAs digital integrated circuits, offers substantial advantages in power consumption and weight over silicon technologies for high-throughput, on-board baseband processor systems. In this paper, current developments in GaAs MMIC technology are described, and the status and prospects of the technology are assessed.

  16. High performance Schottky diodes based on indium-gallium-zinc-oxide

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jiawei; Song, Aimin, E-mail: A.Song@manchester.ac.uk [School of Electrical and Electronic Engineering, University of Manchester, Manchester M13 9PL (United Kingdom); Xin, Qian [School of Physics, Shandong University, Jinan 250100 (China)

    2016-07-15

    Indium-gallium-zinc-oxide (IGZO) Schottky diodes exhibit excellent performance in comparison with conventional devices used in future flexible high frequency electronics. In this work, a high performance Pt IGZO Schottky diode was presented by using a new fabrication process. An argon/oxygen mixture gas was introduced during the deposition of the Pt layer to reduce the oxygen deficiency at the Schottky interface. The diode showed a high barrier height of 0.92 eV and a low ideality factor of 1.36 from the current–voltage characteristics. Even the radius of the active area was 0.1 mm, and the diode showed a cut-off frequency of 6 MHz in the rectifier circuit. Using the diode as a demodulator, a potential application was also demonstrated in this work.

  17. State-of-the-art technologies of gallium oxide power devices

    Science.gov (United States)

    Higashiwaki, Masataka; Kuramata, Akito; Murakami, Hisashi; Kumagai, Yoshinao

    2017-08-01

    Gallium oxide (Ga2 O3 ) has gained increased attention for power devices due to its superior material properties and the availability of economical device-quality native substrates. This review illustrates recent advances in Ga2 O3 device technologies, beginning with an overview of the social circumstances that motivate the development of new-generation switching devices. Following an introduction to the material properties of Ga2 O3 from the viewpoint of power electronics, growth technologies of Ga2 O3 bulk single crystals and epitaxial thin films are discussed. The fabrication and performance of state-of-the-art Ga2 O3 transistors and diodes are then described. We conclude by identifying the directions and challenges of Ga2 O3 power device development in the near future.

  18. Localized surface plasmon resonances in gold nano-patches on a gallium nitride substrate

    International Nuclear Information System (INIS)

    D’Antonio, Palma; Vincenzo Inchingolo, Alessio; Perna, Giuseppe; Capozzi, Vito; Stomeo, Tiziana; De Vittorio, Massimo; Magno, Giovanni; Grande, Marco; Petruzzelli, Vincenzo; D’Orazio, Antonella

    2012-01-01

    In this paper we describe the design, fabrication and characterization of gold nano-patches, deposited on gallium nitride substrate, acting as optical nanoantennas able to efficiently localize the electric field at the metal–dielectric interface. We analyse the performance of the proposed device, evaluating the transmission and the electric field localization by means of a three-dimensional finite difference time domain (FDTD) method. We detail the fabrication protocol and show the morphological characterization. We also investigate the near-field optical transmission by means of scanning near-field optical microscope measurements, which reveal the excitation of a localized surface plasmon resonance at a wavelength of 633 nm, as expected by the FDTD calculations. Such results highlight how the final device can pave the way for the realization of a single optical platform where the active material and the metal nanostructures are integrated together on the same chip. (paper)

  19. Microencapsulation of gallium-indium (Ga-In) liquid metal for self-healing applications.

    Science.gov (United States)

    Blaiszik, B J; Jones, A R; Sottos, N R; White, S R

    2014-01-01

    Microcapsules containing a liquid metal alloy core of gallium-indium (Ga-In) are prepared via in situ urea-formaldehyde (UF) microencapsulation. The capsule size, shape, thermal properties, and shell wall thickness are investigated. We prepare ellipsoidal capsules with major and minor diameter aspect ratios ranging from 1.64 to 1.08 and with major diameters ranging from 245 µm to 3 µm. We observe that as the capsule major diameter decreases, the aspect ratio approaches 1. The thermal properties of the prepared microcapsules are investigated by thermogravimetric (TGA) and differential scanning calorimetry (DSC). Microcapsules are shown to survive incorporation into an epoxy matrix and to trigger via mechanical damage to the cured matrix. Microcapsules containing liquid metal cores may have diverse applications ranging from self-healing to contrast enhancement or the demonstration of mechano-adaptive circuitry.

  20. Direct observation of the orbital spin Kondo effect in gallium arsenide quantum dots

    Science.gov (United States)

    Shang, Ru-Nan; Zhang, Ting; Cao, Gang; Li, Hai-Ou; Xiao, Ming; Guo, Guang-Can; Guo, Guo-Ping

    2018-02-01

    Besides the spin Kondo effect, other degrees of freedom can give rise to the pseudospin Kondo effect. We report a direct observation of the orbital spin Kondo effect in a series-coupled gallium arsenide (GaAs) double quantum dot device where orbital degrees act as pseudospin. Electron occupation in both dots induces a pseudospin Kondo effect. In a region of one net spin impurity, complete spectra with three resonance peaks are observed. Furthermore, we observe a pseudo-Zeeman effect and demonstrate its electrical controllability for the artificial pseudospin in this orbital spin Kondo process via gate voltage control. The fourfold degeneracy point is realized at a specific value supplemented by spin degeneracy, indicating a transition from the SU(2) to the SU(4) Kondo effect.