WorldWideScience

Sample records for scandium phosphides

  1. Gallium phosphide energy converters

    Science.gov (United States)

    Sims, P. E.; DiNetta, Louis C.; DuganCavanagh, K.; Goetz, M. A.

    1996-01-01

    Betavoltaic power supplies based on gallium phosphide can supply long term low-level power with high reliability. Results are presented for GaP devices powered by Ni-63 and tritiarated phosphors. Leakage currents as low as 1.2 x 10(exp -17) A/cm(exp 2) have been measured and the temperature dependence of the reverse saturation current is found to have ideal behavior. A small demonstration system has been assembled that generates and stores enough electricity to light up an LED.

  2. Scandium recovery from slags after oxidized nickel ore processing

    Science.gov (United States)

    Smyshlyaev, Denis; Botalov, Maxim; Bunkov, Grigory; Rychkov, Vladimir; Kirillov, Evgeny; Kirillov, Sergey; Semenishchev, Vladimir

    2017-09-01

    One of the possible sources of scandium production - waste (slags) from processing of oxidized nickel ores, has been considered in present research work. The hydrometallurgical method has been selected as the primary for scandium extraction. Different reagents for leaching of scandium, such as sulfuric acid, various carbonate salts and fluorides, have been tested. Sulfuric acid has been recognized as an optimal leaching reagent. Sulfuric acid concentration of 100 g L-1 allowed recovering up to 97 % of scandium.

  3. Phonon properties of americium phosphide

    Science.gov (United States)

    Arya, B. S.; Aynyas, Mahendra; Sanyal, S. P.

    2016-05-01

    Phonon properties of AmP have been studied by using breathing shell models (BSM) which includes breathing motion of electrons of the Am atoms due to f-d hybridization. The phonon dispersion curves, specific heat calculated from present model. The calculated phonon dispersion curves of AmP are presented follow the same trend as observed in uranium phosphide. We discuss the significance of this approach in predicting the phonon dispersion curves of these compounds and examine the role of electron-phonon interaction.

  4. Methemoglobinemia in aluminum phosphide poisoning.

    Science.gov (United States)

    Shadnia, Shahin; Soltaninejad, Kambiz; Hassanian-Moghadam, Hossein; Sadeghi, Anahaita; Rahimzadeh, Hormat; Zamani, Nasim; Ghasemi-Toussi, Alireza; Abdollahi, Mohammad

    2011-03-01

    Acute aluminum phosphide (AlP) poisoning is one of the most common causes of acute pesticide poisoning in Iran. Hydrogen phosphide or phosphine gas is produced following reaction of AlP with water even at ambient humidity. Methemoglobinemia is a rare finding following phosphine poisoning. In this paper, two cases of fatal AlP poisoning complicated by methemoglobinemia are reported. Two patients presented following suicidal ingestion of AlP tablets. In the Emergency Department (ED), they received gastric lavage with sodium bicarbonate and potassium permanganate. Both of them received supportive care. In each case, hematuria and hemolysis were significant events. The patients also showed a decrease in O(2) saturation in spite of high FIO(2). Methemoglobin levels of 40% and 30% were detected by co-oximetry. Neither patient responded to treatment (ascorbic acid in one case, methylene blue in the other). Both patients died due to systemic effects of phosphine poisoning. Hemolysis and methemoglobinemia may complicate the course of phosphine poisoning that seems resistant to methylene blue and ascorbic acid. Therefore, other treatments including hyperbaric oxygen therapy and exchange blood transfusion should be considered.

  5. Aluminium phosphide induced acute kidney injury

    Directory of Open Access Journals (Sweden)

    Quaiser Saif

    2015-01-01

    Full Text Available Aluminium phosphide is one of the most common agricultural poisons being consumed in north India. Consumption of a fresh tablet is lethal as no antidote is available. Acute intoxication primarily presents with cardiovascular collapse due to myocardial toxicity. We report here a case of acute severe poisoning along with cardiovascular collapse and oliguria. The patient developed acute kidney injury during the illness (a rare entity in aluminium phosphide poisoning, which completely resolved following prompt conservative treatment.

  6. Influence of scandium concentration on power generation figure of merit of scandium aluminum nitride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Akiyama, Morito; Nagase, Toshimi [Measurement Solution Research Center, National Institute of Advanced Industrials Science and Technology, Tosu, Saga 841-0052 (Japan); Umeda, Keiichi; Honda, Atsushi [Murata Manufacturing Co., Ltd., Nagaokakyo, Kyoto 617-8555 (Japan)

    2013-01-14

    The authors have investigated the influence of scandium concentration on the power generation figure of merit (FOM) of scandium aluminum nitride (Sc{sub x}Al{sub 1-x}N) films prepared by cosputtering. The power generation FOM strongly depends on the scandium concentration. The FOM of Sc{sub 0.41}Al{sub 0.59}N film was 67 GPa, indicating that the FOM is five times larger than that of AlN. The FOM of Sc{sub 0.41}Al{sub 0.59}N film is higher than those of lead zirconate titanate and Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} films, which is the highest reported for any piezoelectric thin films. The high FOM of Sc{sub 0.41}Al{sub 0.59}N film is due to the high d{sub 31} and the low relative permittivity.

  7. Lifetime measurements and oscillator strengths in singly ionized scandium and the solar abundance of scandium

    Science.gov (United States)

    Pehlivan Rhodin, A.; Belmonte, M. T.; Engström, L.; Lundberg, H.; Nilsson, H.; Hartman, H.; Pickering, J. C.; Clear, C.; Quinet, P.; Fivet, V.; Palmeri, P.

    2017-12-01

    The lifetimes of 17 even-parity levels (3d5s, 3d4d, 3d6s and 4p2) in the region 57 743-77 837 cm-1 of singly ionized scandium (Sc II) were measured by two-step time-resolved laser induced fluorescence spectroscopy. Oscillator strengths of 57 lines from these highly excited upper levels were derived using a hollow cathode discharge lamp and a Fourier transform spectrometer. In addition, Hartree-Fock calculations where both the main relativistic and core-polarization effects were taken into account were carried out for both low- and high-excitation levels. There is a good agreement for most of the lines between our calculated branching fractions and the measurements of Lawler & Dakin in the region 9000-45 000 cm-1 for low excitation levels and with our measurements for high excitation levels in the region 23 500-63 100 cm-1. This, in turn, allowed us to combine the calculated branching fractions with the available experimental lifetimes to determine semi-empirical oscillator strengths for a set of 380 E1 transitions in Sc II. These oscillator strengths include the weak lines that were used previously to derive the solar abundance of scandium. The solar abundance of scandium is now estimated to logε⊙ = 3.04 ± 0.13 using these semi-empirical oscillator strengths to shift the values determined by Scott et al. The new estimated abundance value is in agreement with the meteoritic value (logεmet = 3.05 ± 0.02) of Lodders, Palme & Gail.

  8. Smelting of Scandium by Microwave Irradiation.

    Science.gov (United States)

    Fujii, Satoshi; Tsubaki, Shuntaro; Inazu, Naomi; Suzuki, Eiichi; Wada, Yuji

    2017-09-27

    Scandium is being explored as an alloying element for aluminum alloys, which are gaining importance as high-performance lightweight structural alloys in the transportation industry. A few years ago, Sc was also found to be suitable for use in electrical devices. High-Sc-content ScAlN thin films have attracted significant attention because of their strong piezoelectricity. The piezoelectric response of ScAlN suggests that ScAlN thin films formed on a hard substrate would be suitable surface acoustic wave wideband filters for next-generation wireless communication systems. However, it is often difficult to use ScAlN thin films in MEMS devices-including acoustic ones-because of the extremely high price of metallic Sc, given the difficulty associated with smelting it. Here, we propose a novel process for smelting Sc metal by microwave irradiation. Sc metal was able to be obtained successfully from ScF₃ through a microwave-irradiation-based carbon reduction reaction. The reaction temperature for this reduction process was approximately 880°C, which is half of that for the conventional smelting process involving reduction with Ca. Thus, the proposed microwave irradiation process has significant potential for use in the smelting of Sc metal.

  9. Smelting of Scandium by Microwave Irradiation

    Directory of Open Access Journals (Sweden)

    Satoshi Fujii

    2017-09-01

    Full Text Available Scandium is being explored as an alloying element for aluminum alloys, which are gaining importance as high-performance lightweight structural alloys in the transportation industry. A few years ago, Sc was also found to be suitable for use in electrical devices. High-Sc-content ScAlN thin films have attracted significant attention because of their strong piezoelectricity. The piezoelectric response of ScAlN suggests that ScAlN thin films formed on a hard substrate would be suitable surface acoustic wave wideband filters for next-generation wireless communication systems. However, it is often difficult to use ScAlN thin films in MEMS devices—including acoustic ones—because of the extremely high price of metallic Sc, given the difficulty associated with smelting it. Here, we propose a novel process for smelting Sc metal by microwave irradiation. Sc metal was able to be obtained successfully from ScF3 through a microwave-irradiation-based carbon reduction reaction. The reaction temperature for this reduction process was approximately 880°C, which is half of that for the conventional smelting process involving reduction with Ca. Thus, the proposed microwave irradiation process has significant potential for use in the smelting of Sc metal.

  10. Hydrometallurgical methods of recovery of scandium from the wastes of various technologies

    Science.gov (United States)

    Molchanova, T. V.; Akimova, I. D.; Smirnov, K. M.; Krylova, O. K.; Zharova, E. V.

    2017-03-01

    The recovery of scandium from the wastes of the production of uranium, titanium, iron-vanadium, and alumina is studied. The applied acid schemes of scandium transfer to a solution followed by ion-exchange recovery and extraction concentration of scandium ensure the precipitation of crude scandium oxides containing up to 5% Sc2O3. Scandium oxides of 99.96-99.99% purity are formed after additional refining of these crude oxides according to an extraction technology using a mixture 15% multiradical phosphine oxide or Cyanex-925 + 15% tributyl phosphate in kerosene.

  11. Synthesis and Reactivity of a Scandium Terminal Hydride: H2  Activation by a Scandium Terminal Imido Complex.

    Science.gov (United States)

    Han, Xianghao; Xiang, Li; Lamsfus, Carlos A; Mao, Weiqing; Lu, Erli; Maron, Laurent; Leng, Xuebing; Chen, Yaofeng

    2017-10-20

    Dihydrogen is easily activated by a scandium terminal imido complex containing the weakly coordinated THF. The reaction proceeds through a 1,2-addition mechanism, which is distinct from the σ-bond metathesis mechanism reported to date for rare-earth metal-mediated H2 activation. This reaction yields a scandium terminal hydride, which is structurally well-characterized, being the first one to date. The reactivity of this hydride is reported with unsaturated substrates, further shedding light on the existence of the terminal hydride complex. Interestingly, the H2 activation can be reversible. DFT investigations further eludciate the mechanistic aspects of the reactivity of the scandium anilido-terminal hydride complex with PhNCS but also on the reversible H2 activation process. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Thermoelectric material comprising scandium doped zinc cadmium oxide

    DEFF Research Database (Denmark)

    2016-01-01

    There is presented a composition of scandium doped Zinc Cadmium Oxide with the general formula ZnzCdxScyO which the inventors have prepared, and for which material the inventors have made the insight that it is particularly advantageous as an n-type oxide material, such as particularly advantageous...

  13. Scandium/carbon filters for soft x rays

    NARCIS (Netherlands)

    Artioukov, IA; Kasyanov, YS; Kopylets, IA; Pershin, YP; Romanova, SA

    2003-01-01

    This Note deals with thin-film soft x-ray filters for operation at the wavelengths near carbon K edge (similar to4.5 nm). The filters were fabricated by magnetron sputtering deposition of thin layers of scandium (total thickness 0.1-0.2 mum) onto films of polypropylene (thickness 1.5 mum) and

  14. Obtaining of Trialkylphosphates in Anodic Dissolution of Copper Phosphide

    OpenAIRE

    A. P. Aueshov; М. S. Satayev; A. S. Tukibayeva

    2014-01-01

    Due to obtain trialkylphosphate is suggested to use anodic solution of copper phosphide in alcohol solutions. At this, it can use copper phosphide, obtained at the processing of wastes of phosphorus production. Moreover, it is presented ways of obtaining of tri-n-butylphosphate and tri-izo-butylphosphate.

  15. Comment on " An update on toxicology of aluminum phosphide "

    Directory of Open Access Journals (Sweden)

    Omid Mehrpour

    2012-10-01

    Full Text Available I read with interest the recent published article by Dr Moghadamnia titled "An update on toxicology of aluminum phosphide". Since aluminum phosphide (AlP poisoning is an important medical concern in Iran, I have had the opportunities to work and publish many papers in this regard. I would like to comment on that paper.

  16. Synthesis, characterization and properties of hollow nickel phosphide nanospheres

    Energy Technology Data Exchange (ETDEWEB)

    Ni Yonghong; Tao Ali; Hu Guangzhi; Cao Xiaofeng; Wei Xianwen; Yang Zhousheng [College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000 (China)

    2006-10-14

    Nickel phosphide (Ni{sub 12}P{sub 5}) hollow nanospheres with a mean diameter of 100 nm and a shell thickness of 15-20 nm have been successfully prepared by a hydrothermal-microemulsion route, using NaH{sub 2}PO{sub 2} as a phosphorus source. XRD, EDS (HR)TEM, SEM and the SAED pattern were used to characterize the final product. Experiments showed that the as-prepared nickel phosphide hollow nanospheres could selectively catalytically degrade some organic dyes such as methyl red and Safranine T under 254 nm UV light irradiation. At the same time, the nickel phosphide hollow nanospheres showed a stronger ability to promote electron transfer between the glass-carbon electrode and adrenalin than nickel phosphide honeycomb-like particles prepared by a simple hydrothermal route. A possible formation process for nickel phosphide hollow nanospheres was suggested based on the experimental results.

  17. Solvent extraction of scandium from lateritic nickel- cobalt ores using different organic reagents

    OpenAIRE

    Ferizoğlu Ece; Kaya Şerif; Topkaya Yavuz A.

    2016-01-01

    Scandium is the most important and strategic metal that can be recovered as a by-product from lateritic nickel-cobalt ores. In this research, different extractants were investigated in order to extract scandium from a sulfate medium by a using a solvent extraction method. Generally, the organic extractants are classified as acidic, neutral and basic organophosphorus compounds. However, in solvent extraction of scandium, the acidic and neutral organophosphorus compounds are preferred due to th...

  18. BASIC RESEARCH ON THE SEPARATION OF SCANDIUM YTTRIUM, AND THE RARE EARTHS BY SOLVENT EXTRACTION.

    Science.gov (United States)

    RARE EARTH ELEMENTS, * SOLVENT EXTRACTION ), (*CHELATE COMPOUNDS, RARE EARTH ELEMENTS), PURIFICATION, ATOMIC SPECTROSCOPY, SCANDIUM, YTTRIUM, PRASEODYMIUM, SAMARIUM, EUROPIUM, GADOLINIUM, TERBIUM, FLUORINE COMPOUNDS, KETONES

  19. Enhanced hydrogen evolution reaction on hybrids of cobalt phosphide and molybdenum phosphide

    Science.gov (United States)

    Fang, Si-Ling; Chou, Tsu-Chin; Samireddi, Satyanarayana; Chen, Kuei-Hsien; Chen, Li-Chyong; Chen, Wei-Fu

    2017-03-01

    Production of hydrogen from water electrolysis has stimulated the search of sustainable electrocatalysts as possible alternatives. Recently, cobalt phosphide (CoP) and molybdenum phosphide (MoP) received great attention owing to their superior catalytic activity and stability towards the hydrogen evolution reaction (HER) which rivals platinum catalysts. In this study, we synthesize and study a series of catalysts based on hybrids of CoP and MoP with different Co/Mo ratio. The HER activity shows a volcano shape and reaches a maximum for Co/Mo = 1. Tafel analysis indicates a change in the dominating step of Volmer-Hyrovský mechanism. Interestingly, X-ray diffraction patterns confirmed a major ternary interstitial hexagonal CoMoP2 crystal phase is formed which enhances the electrochemical activity.

  20. A new approach to synthesize supported ruthenium phosphides for hydrodesulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qingfang [Tianjin Key Laboratory of Water Environment and Resources, Tianjin Normal University, Tianjin 300387 (China); Key Laboratory of Advanced Energy Materials Chemistry (MOE), Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), College of Chemistry, Nankai University, Tianjin 300071 (China); Wang, Zhiqiang [Tianjin Key Laboratory of Water Environment and Resources, Tianjin Normal University, Tianjin 300387 (China); Yin, Xiaoqian; Zhou, Linxi [Key Laboratory of Advanced Energy Materials Chemistry (MOE), Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), College of Chemistry, Nankai University, Tianjin 300071 (China); Zhang, Minghui, E-mail: zhangmh@nankai.edu.cn [Key Laboratory of Advanced Energy Materials Chemistry (MOE), Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), College of Chemistry, Nankai University, Tianjin 300071 (China); College of Chemistry and Environmental Science, Kashgar University, Kashgar 844006 (China)

    2016-02-15

    Highlights: • We bring out a new method to synthesize noble metal phosphides at low temperature. • Both RuP and Ru{sub 2}P were synthesized using triphenylphosphine as phosphorus sources. • Ru{sub 2}P was the better active phase for HDS than RuP and metal Ru. • RuP/SiO{sub 2} prepared by new method had better HDS activity to that by TPR method. - Abstract: Supported noble metal ruthenium phosphides were synthesized by one-step H{sub 2}-thermal treatment method using triphenylphosphine (TPP) as phosphorus sources at low temperatures. Two phosphides RuP and Ru{sub 2}P can be prepared by this method via varying the molar ratio of metal salt and TPP. The as-prepared phosphides were characterized by X-ray powder diffraction (XRD), low-temperature N{sub 2} adsorption, CO chemisorption and transmission electronic microscopy (TEM). The supported ruthenium phosphides prepared by new method and conventional method together with contradistinctive metallic ruthenium were evaluated in hydrodesulfurization (HDS) of dibenzothiophene (DBT). The catalytic results showed that metal-rich Ru{sub 2}P was the better active phase for HDS than RuP and metal Ru. Besides this, ruthenium phosphide catalyst prepared by new method exhibited superior HDS activity to that prepared by conventional method.

  1. A Rare but Potentially Fatal Poisoning; Aluminum Phosphide Poisoning

    Directory of Open Access Journals (Sweden)

    Orkun Tolunay

    2017-04-01

    Full Text Available Phosphide, a very toxic gas, is used in our country as aluminium phosphide tablets impregnated in clay. It is widely used since it has a very high diffusion capacity, whereby it can eradicate all living creatures in any form of their life cycle and does not leave any remnants in agricultural products. Aluminum phosphide poisoning is among intoxications for which there are still no true antidotes. Mortality rate varies between 30% and 100%. This paper presents a case of aluminum phosphide poisoning caused by the uncompleted suicide attempt. A 14-year-old girl, who swallowed aluminum phosphate tablets, was brought to the emergency department with the complaints of nausea and vomiting. The patient was treated with gastric lavage and activated charcoal. Since the patient ingested a lethal amount of aluminum phosphide, she was referred to the pediatric intensive care unit. The patient was discharged in stable condition after supportive care and monitoring. Specific antidotes are life-saving in poisonings. However, this case was presented to show how general treatment principles and quick access to health services affect the result of treatment. Also, we aimed to highlight the uncontrolled selling of aluminum phosphate, which results in high mortality rates in case of poisoning.

  2. Controlled synthesis and magnetic properties of nickel phosphide and bimetallic iron-nickel phosphide nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Bhupendra; Ho, Chia-Ling [National Cheng Kung University, Department of Chemical Engineering, Taiwan (China); Tseng, Yuan-Chieh [National Chiao Tung University, Department of Materials Science and Engineering, Taiwan (China); Lo, Chieh-Tsung, E-mail: tsunglo@mail.ncku.edu.tw [National Cheng Kung University, Department of Chemical Engineering, Taiwan (China)

    2012-02-15

    Nickel phosphide (Ni{sub 2}P) and bimetallic iron-nickel phosphides [(Fe{sub x}Ni{sub y}){sub 2}P] nanorods were fabricated by a seeded growth strategy. This strategy utilized pre-synthesized Fe{sub 3}O{sub 4} nanoparticles as seeds and the thermal decomposition of metal precursors by multiple injections in a solution containing trioctylphosphine and didodecyldimethylammonium bromide (DDAB). The nanorods were characterized by transmission electron microscopy, X-ray diffraction, and magnetic measurements were carried out using superconducting quantum interference device (SQUID). The rod length was tunable, ranging from 10 to 110 nm depending on the number of injections, whereas the diameter of the rods was nearly 6 nm. It was found that the rod size increased with the number of injections under the constant total injection concentration and reaction time. In addition, the effect of the DDAB quantity used as a co-surfactant was studied, which showed that an optimum quantity was required to achieve uniform nanorods. Magnetic characterizations were performed over the two kinds of nanorods to identify their respective magnetic phases. The results demonstrated that the Ni{sub 2}P nanorods were defined as a Curie-Weiss paramagnet, whereas the (Fe{sub x}Ni{sub y}){sub 2}P nanorods exhibited superparamagnetic characteristics.

  3. Determination of scandium concentrate composition by WD-XRF and ICP-MS methods

    Science.gov (United States)

    Sarkisova, A. S.; Shibitko, A. O.; Abramov, A. V.; Rebrin, O. I.; Bunkov, G. M.; Lisienko, D. G.

    2017-09-01

    WD-XRF spectroscopy was applied for determining composition of scandium concentrate (ScC) containing 70 % scandium fluoride. Determination of ScC composition was performed using 6 glass beads reference materials produced by fusing synthesized mixture of analyte compounds with the lithium-borate flux in the ratio of 1:10. ScC powder with the known composition was then used as a powder pellet reference material to analyze scandium concentrate from technological line by external standard method. ICP-MS method was employed to control the ScC composition. The statistical data processing and metrological parameters evaluation of the analytical technique developed were carried out.

  4. An update on toxicology of aluminum phosphide

    Directory of Open Access Journals (Sweden)

    Moghadamnia Ali

    2012-09-01

    Full Text Available Abstract Aluminum phosphide (AlP is a cheap solid fumigant and a highly toxic pesticide which is commonly used for grain preservation. In Iran it is known as the “rice tablet”. AlP has currently aroused interest with increasing number of cases in the past four decades due to increased use in agricultural and non-agricultural purposesand also its easy availability in the markets has increased its misuse to commit suicide. Upon contact with moisture in the environment, AlP undergoes a chemical reaction yielding phosphine gas, which is the active pesticidal component. Phosphine inhibits cellular oxygen utilization and can induce lipid peroxidation. It was reported that AlP has a mortality rate more than 50% of intoxication cases. Poisoning with AlP has usually occurred in attempts to suicide. It is a more common case in adults rather than teen agers. In some eastern countries it is a very common agent with rapid action for suicide. Up to date, there is no effective antidote or treatment for its intoxication. Also, some experimental results suggest that magnesium sulfate, N-acetyl cysteine (NAC, glutathione, vitamin C and E, beta-carotenes, coconut oil and melatonin may play an important role in reducing the oxidative outcomes of phosphine. This article reviews the experimental and clinical features of AlP intoxication and tries to suggest a way to encounter its poisoning.

  5. An Update on Toxicology of Aluminum Phosphide

    Directory of Open Access Journals (Sweden)

    Ali Akbar Moghhadamnia

    2012-09-01

    Full Text Available Aluminum phosphide (AlP is a cheap solid fumigant and a highly toxic pesticide which is commonly used for grain preservation. In Iran it is known as the "rice tablet". AlP has currently aroused interest with increasing number of cases in the past four decades due to increased use in agricultural and non-agricultural purposes and also its easy availability in the markets has increased its misuse to commit suicide. Upon contact with moisture in the environment, AlP undergoes a chemical reaction yielding phosphine gas, which is the active pesticidal component. Phosphine inhibits cellular oxygen utilization and can induce lipid peroxidation. It was reported that AlP has a mortality rate more than 50% of intoxication cases. Poisoning with AlP has usually occurred in attempts to suicide. It is a more common case in adults rather than teen agers. In some eastern countries it is a very common agent with rapid action for suicide. Up to date, there is no effective antidote or treatment for its intoxication. Also, some experimental results suggest that magnesium sulfate, N-acetyl cysteine (NAC, glutathione, vitamin C and E, beta-carotenes, coconut oil and melatonin may play an important role in reducing the oxidative outcomes of phosphine. This article reviews the experimental and clinical features of AlP intoxication and tries to suggest a way to encounter its poisoning.

  6. Acute aluminium phosphide poisoning, what is new?

    Directory of Open Access Journals (Sweden)

    Yatendra Singh

    2014-01-01

    Full Text Available Aluminium phosphide (AlP is a cheap solid fumigant and a highly toxic pesticide that is commonly used for grain preservation. AlP has currently generated interest with increasing number of cases in the past four decades because of its increased use for agricultural and nonagricultural purposes, and also its easy availability in the markets has led to its increased misuse to commit suicide. Ingestion is usually suicidal in intent, uncommonly accidental and rarely homicidal. The poison affects all systems, shock, cardiac arrhythmias with varied ECG changes and gastrointestinal features being the most prominent. Diagnosis is made on the basis of clinical suspicion, a positive silver nitrate paper test to phosphine, and gastric aspirate and viscera biochemistry. Treatment includes early gastric lavage with potassium permanganate or a combination of coconut oil and sodium bicarbonate, administration of charcoal and palliative care. Specific therapy includes intravenous magnesium sulphate and oral coconut oil. Unfortunately, the lack of a specific antidote Results in very high mortality and the key to treatment lies in rapid decontamination and institution of resuscitative measures. This article aims to identify the salient features and mechanism of AlP poisoning along with its management strategies and prognostic variables.

  7. Tin etching from metallic and oxidized scandium thin films

    Science.gov (United States)

    Pachecka, M.; Lee, C. J.; Sturm, J. M.; Bijkerk, F.

    2017-08-01

    The role of oxide on Sn adhesion to Sc surfaces was studied with in-situ ellipsometry, X-ray photoelectron spectroscopy and secondary electron microscopy. Sn etching with hydrogen radicals was performed on metallic Sc, metallic Sc with a native oxide, and a fully oxidized Sc layer. The results show that Sn adsorbs rather weakly to a non-oxidized Sc surface, and is etched relatively easily by atomic hydrogen. In contrast, the presence of native oxide on Sc allows Sn to adsorb more strongly to the surface, slowing the etching. Furthermore, thinner layers of scandium oxide result in weaker Sn adsorption, indicating that the layer beneath the oxide plays a significant role in determining the adsorption strength. Unexpectedly, for Sn on Sc2O3, and, to a lesser extent, for Sn on Sc, the etch rate shows a variation over time, which is explained by surface restructuring, temperature change, and hydrogen adsorption saturation.

  8. Tin etching from metallic and oxidized scandium thin films

    Directory of Open Access Journals (Sweden)

    M. Pachecka

    2017-08-01

    Full Text Available The role of oxide on Sn adhesion to Sc surfaces was studied with in-situ ellipsometry, X-ray photoelectron spectroscopy and secondary electron microscopy. Sn etching with hydrogen radicals was performed on metallic Sc, metallic Sc with a native oxide, and a fully oxidized Sc layer. The results show that Sn adsorbs rather weakly to a non-oxidized Sc surface, and is etched relatively easily by atomic hydrogen. In contrast, the presence of native oxide on Sc allows Sn to adsorb more strongly to the surface, slowing the etching. Furthermore, thinner layers of scandium oxide result in weaker Sn adsorption, indicating that the layer beneath the oxide plays a significant role in determining the adsorption strength. Unexpectedly, for Sn on Sc2O3, and, to a lesser extent, for Sn on Sc, the etch rate shows a variation over time, which is explained by surface restructuring, temperature change, and hydrogen adsorption saturation.

  9. Extraction of scandium by liquid di-2-ethylhexylphosphoric acid in fusible diluents

    Directory of Open Access Journals (Sweden)

    Ainur Isatayeva

    2015-03-01

    Full Text Available Currently widespread distribution of extraction methods using fusible reagents can be explained by a number of advantages, such as high kinetic characteristics of the process, the ease separation of two phases, high selectivity of many extractants, relatively complete regeneration. For the extraction of scandium in technological order, neutral and cation exchange extractants can be used. Several extraction reagents melt easily at high temperatures, and such melts can be used for extraction. Efficiency of the extraction of metal by cation reagents depends on many factors. Extraction of scandium by melt mixtures of di-2-ethylhexylphosphoric acid - higher carboxylic acid - paraffin and the effect of acidity of the aqueous phase, the concentration of scandium and the aqueous extractant in the organic phase, the volume ratio of organic and aqueous phases on the extraction of metal were studied. It was found that the extraction of scandium proceeds through the cation exchange mechanism. Scandium was extracted quantitatively (> 99.0% from acid solutions. The optimal concentration of di-2-ethylhexylphosphoric acid in the extractant was 0,250 M, quantitative extraction of scandium was observed in the range of its concentrations of 10-3-10-6 M and the volume ratio of organic phases to aqueous phases of 1:5 - 1:20.

  10. Fatal aluminum phosphide poisonings in Tirana (Albania), 2009 - 2013.

    Science.gov (United States)

    Sulaj, Zihni; Drishti, Alert; Çeko, Irena; Gashi, Amarda; Vyshka, Gentian

    2015-01-25

    Acute poisonings particularly through pesticides have become a major public health concern in Albania during the last decade. The number of fatalities due to aluminum phosphide intoxications was more than doubled during a five year-period from 2009 to 2013, and a cluster of suicides perpetrated with Phostoxin was registered. Several factors are accountable for such a phenomenon, including the fact that aluminum phosphide agents are freely available in the Albanian market, their price is extremely low and they are sold without any legal restriction. The mass media unfortunately warranted an emulating effect to dramatic intoxications, which gained by such means the notoriety of a secure lethal weapon. Our experience with more than three hundred intoxications with aluminum phosphide agents in the last five years, showed that a considerable delay from the moment of exposure (mainly through ingestion) to specialized medical help seeking, created a considerable obstacle for a successful treatment of cases, and eventually for the survival of patients. The lack of a specific antidote adds further challenges to all these exposures. The need for public health policies aiming at prevention, awareness, and possibly the substitution of Phostoxin or other aluminum phosphide pesticides with less dangerous agents is formulated.

  11. Polyserositis: An Unusual Complication of Aluminum Phosphide Poisoning

    Directory of Open Access Journals (Sweden)

    Ashish Bhalla

    2012-12-01

    Full Text Available   Background: Aluminum phosphide is the common cause of poisoning in adults in India, with a very high case fatality ratio. We studied five patients of aluminum phosphide poisoning with polyserositis. Methods: We enrolled all patients with aluminum phosphide poisoning presenting to emergency medical department, at a tertiary care hospital in northwestern India from January to July 2006. These patients were managed according to a standard treatment protocol and their complications were recorded. Results: During the study period, total of 35 patients were admitted with 57.5% mortality in the first 12 hours. Among the rest, 5 patients were found to develop polyserositis. All these patients had severe hypotension at presentation and developed respiratory distress requiring mechanical ventilation after an average stay of 3.8 days post-ingestion. They were managed conservatively and four of them were discharged from the hospital after the average stay of 10 days. Conclusion: In this case series, features of polyserositis (pleural effusion, ascites and pericardial effusion were found in 15% patients of severe aluminum phosphide poisoning. We postulate systemic capillary leak syndrome, secondary to mitochondrial damage in the endothelium, as a possible mechanism.        

  12. Optical and photocatalytic properties of indium phosphide nanoneedles and nanotubes

    DEFF Research Database (Denmark)

    Yu, Yanlong; Yu, Cuiyan; Xu, Tao

    2017-01-01

    Large scale indium phosphide (InP) nanoneedles and nanotubes were synthesized through a facile solvothermal reaction. The morphology and microstructure of the samples were analyzed by employing scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and Ult...... an enhanced photocatalytic performance as compared to the InP nanoneedles and nanoparticles. [All rights reserved Elsevier]....

  13. Thermodynamic and kinetic study of scandium(III) complexes of DTPA and DOTA: a step toward scandium radiopharmaceuticals.

    Science.gov (United States)

    Pniok, Miroslav; Kubíček, Vojtěch; Havlíčková, Jana; Kotek, Jan; Sabatie-Gogová, Andrea; Plutnar, Jan; Huclier-Markai, Sandrine; Hermann, Petr

    2014-06-23

    Diethylenetriamine-N,N,N',N'',N''-pentaacetic acid (DTPA) and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) scandium(III) complexes were investigated in the solution and solid state. Three (45)Sc NMR spectroscopic references suitable for aqueous solutions were suggested: 0.1 M Sc(ClO4)3 in 1 M aq. HClO4 (δSc =0.0 ppm), 0.1 M ScCl3 in 1 M aq. HCl (δSc =1.75 ppm) and 0.01 M [Sc(ox)4](5-) (ox(2-) = oxalato) in 1 M aq. K2C2O4 (δSc =8.31 ppm). In solution, [Sc(dtpa)](2-) complex (δSc = 83 ppm, Δν = 770 Hz) has a rather symmetric ligand field unlike highly unsymmetrical donor atom arrangement in [Sc(dota)](-) anion (δSc = 100 ppm, Δν = 4300 Hz). The solid-state structure of K8[Sc2(ox)7]⋅13 H2O contains two [Sc(ox)3](3-) units bridged by twice "side-on" coordinated oxalate anion with Sc(3+) ion in a dodecahedral O8 arrangement. Structures of [Sc(dtpa)](2-) and [Sc(dota)](-) in [(Hguanidine)]2[Sc(dtpa)]⋅3 H2O and K[Sc(dota)][H6 dota]Cl2⋅4 H2O, respectively, are analogous to those of trivalent lanthanide complexes with the same ligands. The [Sc(dota)](-) unit exhibits twisted square-antiprismatic arrangement without an axial ligand (TSA' isomer) and [Sc(dota)](-) and (H6 dota)(2+) units are bridged by a K(+) cation. A surprisingly high value of the last DOTA dissociation constant (pKa =12.9) was determined by potentiometry and confirmed by using NMR spectroscopy. Stability constants of scandium(III) complexes (log KScL 27.43 and 30.79 for DTPA and DOTA, respectively) were determined from potentiometric and (45)Sc NMR spectroscopic data. Both complexes are fully formed even below pH 2. Complexation of DOTA with the Sc(3+) ion is much faster than with trivalent lanthanides. Proton-assisted decomplexation of the [Sc(dota)](-) complex (τ1/2 =45 h; 1 M aq. HCl, 25 °C) is much slower than that for [Ln(dota)](-) complexes. Therefore, DOTA and its derivatives seem to be very suitable ligands for scandium

  14. Effects of iron on intermetallic compound formation in scandium modified Al–Si–Mg Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Patakham, Ussadawut [National Metal and Materials Technology Center, National Science and Technology Development Agency, 114 Thailand Science Park, Klong Nueng, Klong Luang, Pathumthani 12120 (Thailand); Limmaneevichitr, Chaowalit, E-mail: chaowalit.lim@mail.kmutt.ac.th [Production Engineering Department, Faculty of Engineering, King Mongkut’s University of Technology Thonburi, 126 Pracha-Utid Rd., Bangmod, Tungkhru, Bangkok 10140 (Thailand)

    2014-12-15

    Highlights: • Iron reduces the modification effects of scandium in Al–Si–Mg alloys. • Morphologies of Sc-rich intermetallic phases vary with Fe and Sc contents and the cooling rates. • Sc neutralizes effects of Fe by changing Fe-rich intermetallic phases from platelets to more cubic. - Abstract: In general, iron has a strong tendency to dissolve in molten aluminum. Iron has very low solid solubility in aluminum–silicon casting alloys, so it will form intermetallic compounds that cause detrimental effects on mechanical properties. In this work, the effects of iron on intermetallic compound formations in scandium modified Al–Si–Mg alloys were studied. There were two levels of iron addition (0.2 and 0.4 wt.%) and two levels of scandium addition (0.2 and 0.4 wt.%). We found that the effects of scandium modification decreased with increasing iron addition. The morphologies of the complex intermetallic compounds were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and electron backscatter diffraction (EBSD) techniques. It was found that scandium changes the morphology of Fe-rich intermetallic compounds from β-phase (plate-like) to α-phase, which reduces the harmful effects of β-phase.

  15. Solvent extraction of scandium from lateritic nickel- cobalt ores using different organic reagents

    Directory of Open Access Journals (Sweden)

    Ferizoğlu Ece

    2016-01-01

    Full Text Available Scandium is the most important and strategic metal that can be recovered as a by-product from lateritic nickel-cobalt ores. In this research, different extractants were investigated in order to extract scandium from a sulfate medium by a using a solvent extraction method. Generally, the organic extractants are classified as acidic, neutral and basic organophosphorus compounds. However, in solvent extraction of scandium, the acidic and neutral organophosphorus compounds are preferred due to their higher extraction efficiencies. Thus, the aim of the present study was to compare the scandium extraction efficiencies of some acidic and neutral organic reagents. For this reason, Ionquest 290 (Bis(2,4,4-trimethylpenthyl phosphonic acid, DEHPA (Di(2-ethylhexyl phosphoric acid, Cyanex 272 ((Bis(2,4,4-trimethylpentyl phosphinic acid which are acidic organophosphorus compounds, and Cyanex 923 (Trialkylphosphine oxide, which is a neutral organophosphorus compound, were used. The extraction capacities of these organics were studied with respect to the extractant concentration at same pH and phase ratio. As a result of the study, DEHPA was found to have higher scandium extraction efficiency with lower iron extraction at pH = 0.55 at a phase ratio of 10:1 = A:O.

  16. Correlation between stoichiometry and properties of scandium oxide films prepared by reactive magnetron sputtering

    Science.gov (United States)

    Belosludtsev, Alexandr; Juškevičius, Kęstutis; Ceizaris, Lukas; Samuilovas, Romanas; Stanionytė, Sandra; Jasulaitienė, Vitalija; Kičas, Simonas

    2018-01-01

    Scandium oxide films were deposited on fused silica substrates by reactive pulsed DC magnetron sputtering. The use of feed-back optical emission monitoring enabled high-rate reactive deposition of films with tunable stoichiometry and properties. The under-stoichiometric, stoichiometric and over-stoichiometric scandium oxide films were prepared. The compressive stress in films was between 235 and 530 MPa. We showed that phase structure, density, surface roughness and optical properties of the scandium oxide are affected by the film stoichiometry and deposition conditions. Transparent scandium oxide films were slightly hydrophobic (94 ± 3°), homogeneous with a crystallite size of 20 ± 5 nm. The lowest extinction coefficient 0.7 × 10-3, the highest refractive index 2.08 (both quantities at the wavelength of 355 nm) and the highest density 4.1 ± 0.1 g cm-3 exhibited film prepared with the stoichiometric composition. Stoichiometric scandium oxide can be used in various optical applications as high refractive index and wide bandgap material. Transitions to under- or over-stoichiometry lead to a decrease of film density, refractive index and increase of the extinction coefficient.

  17. Mossbauer investigation of scandium oxide-hematite nanoparticles

    Science.gov (United States)

    Allwes, Mark; Sorescu, Monica

    Scandium oxide-doped hematite, xSc2O3*(1-x)alpha-Fe2O3 with molar concentration x =0.1, 0.3, and 0.5 was prepared by using ball milling, taking samples at times 0, 2, 4, 8, and 12 hours. The resulting Mossbauer spectra of the nanoparticles systems were parameterized using NORMOS-90. For each concentration, the spectra at 0 hours only consisted of 1 sextet, as the substitution of Sc2O3into Fe2O3 did not appear until after 2 hours of ball milling time (BMT). Concentration x =0.1 at BMT 2hours consisted of 2 sextets while x =0.3 and 0.5 were fit with 1 sextet and 1 quadrupole-split doublet. Concentration x =0.1 at BMT 4 and 8 hours consisted of 3 sextets, and at BMT 12 hours consisted of 4 sextets. For concentrations x =0.3 and 0.5 at BMT 4, 8, and 12 hours the spectra were fit with 3 sextets and 1 quadrupole-split doublet. With increasing initial concentration, the appearance of the quadrupole-split doublet became more pronounced, indicating the substitution of Fe into Sc2O3 occurred. But for x =0.1, the BMT did influence the number of sextets needed, causing an increase in substitution of Sc2O3 into Fe2O3.

  18. Association between toenail scandium levels and risk of acute myocardial infarction in European men: The EURAMIC and Heavy Metals Study

    NARCIS (Netherlands)

    Gómez-Aracena, J.; Martin-Moreno, J.M.; Riemersma, R.A.; Bode, P.; Gutiérrez-Bedmar, M.; Gorgojo, L.; Kark, J.D.; Garcia-Rodríguez, A.; Gomez-Gracia, E.; Kardinaal, A.F.M.; Aro, A.; Veer, P. van 't; Wedel, H.; Kok, F.J.; Fernández-Crehuet, J.

    2002-01-01

    The association between scandium status and risk of acute myocardial infarction (MI) was examined in a multicentre case control study in 10 centres from Europe and Israel. Scandium in toenails was assessed in 684 cases and 724 controls less than 70 years of age. Mean concentrations of toenail

  19. In-source laser spectroscopy developments at TRILIS-towards spectroscopy on actinium and scandium

    Energy Technology Data Exchange (ETDEWEB)

    Raeder, Sebastian, E-mail: raeder@triumf.ca; Dombsky, Marik; Heggen, Henning; Lassen, Jens; Quenzel, Thomas [TRIUMF, Canada' s National Laboratory for Nuclear and Particle Physics (Canada); Sjoedin, Marica [GANIL (France); Teigelhoefer, Andrea [TRIUMF, Canada' s National Laboratory for Nuclear and Particle Physics (Canada); Wendt, Klaus [Johannes Gutenberg-Universitaet Mainz, Institut fuer Physik (Germany)

    2013-04-15

    Resonance Ionization Laser Ion Sources (RILIS) have become a versatile tool for production and study of exotic nuclides at Isotope Separator On-Line (ISOL) facilities such as ISAC at TRIUMF. The recent development and addition of a grating tuned spectroscopy laser to the TRIUMF RILIS solid state laser system allows for wide range spectral scans to investigate atomic structures on short lived isotopes, e.g., those from the element actinium, produced in uranium targets at ISAC. In addition, development of new and improved laser ionization schemes for rare isotope production at ISAC is ongoing. Here spectroscopic studies on bound states, Rydberg states and autoionizing (AI) resonances on scandium using the existing off-line capabilities are reported. These results allowed to identify a suitable ionization scheme for scandium via excitation into an autoionizing state at 58,104 cm{sup - 1} which has subsequently been used for ionization of on-line produced exotic scandium isotopes.

  20. Process and Mechanical Properties: Applicability of a Scandium modified Al-alloy for Laser Additive Manufacturing

    Science.gov (United States)

    Schmidtke, K.; Palm, F.; Hawkins, A.; Emmelmann, C.

    The applicability of an aluminium alloy containing scandium for laser additive manufacturing (LAM) is considered. Modified aluminium alloys with a scandium content beyond the eutectic point offer great potential to become a high prioritized aerospace material. Depending on other alloying elements like magnesium or zirconium, strongly required weight reduction, corrosion resistance and improved strength properties of metallic light weight alloys can be achieved. The development, production and testing of parts built up by a laser powder bed process will be presented with regard to the qualification of the new material concept "ScalmalloyRP®" for laser additive manufacturing.

  1. Synthesis and structural characterization of scandium SALEN complexes.

    Science.gov (United States)

    Meermann, Christian; Sirsch, Peter; Törnroos, Karl W; Anwander, Reiner

    2006-02-28

    A series of heteroleptic scandium SALEN complexes, [(SALEN)Sc(mu-Cl)]2 and (SALEN)Sc[N(SiHMe2)2] is obtained via amine elimination reactions using [Sc(N(i)Pr2)2(mu-Cl)(THF)]2 and Sc[N(SiHMe2)2]3(THF) as metal precursors, respectively. H(2)SALEN ligand precursors comprising H2Salen [(1,2-ethandiyl)bis(nitrilomethylidyne)bis(2,4-di-tert-butyl)phenol], H2Salpren [(2,2-dimethylpropanediyl)bis(nitrilomethylidyne)bis(2,4-di-tert-butyl)phenol], H2Salcyc [(1R,2R)-(-)-1,2-cyclohexanediyl)bis(nitrilomethylidyne)bis(2,4-di-tert-butyl)phenol] and H2Salphen [((1S,2S)-(-)-1,2-diphenylethandiyl)bis(nitrilomethylidyne)bis(2,4-di-tert-butyl)phenol] are selected according to solubility and ligand backbone variation ("=N-(R)-N=" bite angle) criteria. Consideration is given to the feasibility of [Cl --> NR2] and [N(SiHMe2)2--> OSiR3] secondary ligand exchange reactions. X-ray crystal structure analyses of donor-free (Salpren)Sc(N(i)Pr2), (R,R)-(Salcyc)Sc[N(SiHMe2)2], (Salen)Sc(OSi(t)BuPh2) and (Salphen)Sc(OSiH(t)Bu2) reveal (i) a very short Sc-N bond distance of 2.000(3) A, (ii) weak beta(Si-H)(amido)-Sc agostic interactions and (iii) an exclusive intramolecularly tetradentate and intrinsically bent coordination mode of the SALEN ligands with angle(Ph,Ph) dihedral angles and Sc-[N(2)O(2)] distances in the 124.27(9)-127.7(3) degrees and 0.638(1)-0.688(1) A range, respectively.

  2. Scandium SALEN complexes bearing chloro, aryloxo, and hydroxo ligands.

    Science.gov (United States)

    Meermann, Christian; Törnroos, Karl W; Anwander, Reiner

    2009-03-16

    Heteroleptic amide complexes (SALEN)Sc[N(SiHMe(2))(2)] (SALEN = Salen(tBu,tBu), Salcyc(tBu,tBu), or Salpren(tBu,tBu) if not stated differently) were examined as synthesis precursors according to silylamine elimination reactions. Treatment of (SALEN)Sc[N(SiHMe(2))(2)] with H(2)O or phenols (HOAr(R,R); R = tBu, iPr) afforded complexes [(SALEN)Sc(mu-OH)](2) and (SALEN)Sc(OAr(R,R)), while chloro exchange products were formed from the respective reactions with NH(4)Cl or AlMe(2)Cl. Such complexes [(SALEN)Sc(mu-Cl)](2) and (SALEN)ScCl(thf) were also obtained by utilizing alternative synthesis protocols, allowing for controlled donor absence and presence. Heteroleptic amide precursors [Sc(NiPr(2))(2)(mu-Cl)(thf)](2) and [Sc[N(SiHMe(2))(2)](2)(mu-Cl)(thf)](2) readily undergo amine elimination reactions with H(2)SALEN derivatives to form the corresponding chloride complexes. Spectroscopic and X-ray structural data of the heteroleptic scandium complexes revealed an exclusive intramolecular tetradentate coordination mode of the SALEN ligands independent of the SALEN ligand bite angle and the nature of the "second" ligand (chloro, amido, aryloxo, hydroxo). The coordination of the SALEN ligands is rationalized on the basis of (a) the displacement d of the metal center from the [N(2)O(2)] least-squares plane, (b) the dihedral angle alpha between the phenyl rings of the salicylidene moieties, and (c) the angle beta = Ct-Ln-Ct (Ct = centroid of the phenyl rings) in the case of strongly twisted ligands.

  3. Vertical distribution of scandium in the north central Pacific

    Science.gov (United States)

    Amakawa, Hiroshi; Nomura, Miho; Sasaki, Kazunori; Oura, Yasuji; Ebihara, Mitsuru

    2007-06-01

    The concentrations of scandium (Sc) in seawater, which have remained unreported since the early 1970s, were determined together with those of yttrium (Y) and lanthanides (Ln) with samples from the north central Pacific Ocean (St. BO-3). The Sc concentration shows a so-called nutrient-like profile: it increases gradually from the surface (about 2 pmol/kg) to the ocean floor (about 20 pmol/kg). That pattern closely resembles those of Y and Ln (correlation coefficient (r) > 0.92). Some light-to-middle Ln (Pr-Tb) exhibit a closer correlation with Sc than do Y, La, or heavy Ln (Ho-Lu). In contrast, Y/Sc and Ln/Sc ratios (elemental abundance ratios) indicate that Sc is depleted compared to either Y or Ln in seawater more than in loess, which represents chemical compositions of crustal material. These observations offer a conflicting view of chemical reactivity related Y, Ln, and Sc: r values show that the chemical reactivity of Sc resembles those of Y and Ln, but differences of Y/Sc and Ln/Sc ratios in seawater and in loess suggest that the chemical reactivity of Sc differs from those of Y and Ln. More Sc data for seawater are necessary to clarify the chemical reactivity of Sc in the ocean. We also propose that comparative studies of vertical profiles of Sc and such elements as Fe, Ti, Zr, and Hf showing so-called nutrient-like profiles at the same oceanic stations would be helpful and effective for clarifying the behavior of Sc in the ocean.

  4. Indium phosphide space solar cell research: Where we are and where we are going

    Science.gov (United States)

    Jain, R. K.; Flood, D. J.; Weinberg, Irving

    1995-01-01

    Indium phosphide is considered to be a strong contender for many photovoltaic space applications because of its radiation resistance and its potential for high efficiency. An overview of recent progress is presented, and possible future research directions for indium phosphide space solar cells are discussed. The topics considered include radiation damage studies and space flight experiments.

  5. In situ observation of the reaction of scandium and carbon by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Juarez-Arellano, Erick A., E-mail: eajuarez@unpa.edu.m [Institut fuer Geowissenschaften, Universitaet Frankfurt, Altenhoeferallee 1, 60438 Frankfurt a.M. (Germany); Universidad del Papaloapan, Circuito Central 200, Parque Industrial, Tuxtepec 68301 (Mexico); Winkler, Bjorn [Institut fuer Geowissenschaften, Universitaet Frankfurt, Altenhoeferallee 1, 60438 Frankfurt a.M. (Germany); Vogel, Sven C. [Los Alamos National Laboratory, Lujan Center. Mail Stop H805, Los Alamos, NM 87545 (United States); Senyshyn, Anatoliy [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Technische Universitaet Muenchen, Lichtenbergstr. 1, D-85747 Garching (Germany); Materialwissenschaft, TU Darmstadt, Petersensstr. 23, D-64287 Darmstadt (Germany); Kammler, Daniel R. [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Avalos-Borja, Miguel [CNyN, UNAM, A. Postal 2681, Ensenada, B.C. (Mexico)

    2011-01-05

    Research highlights: {yields} Exist two ScC cubic phases with B1-structure type differing in site occupancy of C. {yields} A new orthorhombic scandium carbide phase is formed at 1473(50) K. {yields} The recrystallization of alpha-Sc occurs between 1000 and 1223 K. - Abstract: The formation of scandium carbides by reaction of the elements has been investigated by in situ neutron diffraction up to 1823 K. On heating, the recrystallization of {alpha}-Sc occurs between 1000 and 1223 K. The formation of Sc{sub 2}C and ScC (NaCl-B1 type structure) phases has been detected at 1323 and 1373 K, respectively. The formation of a new orthorhombic scandium carbide phase was observed at 1473(50) K. Once the scandium carbides are formed they are stable upon heating or cooling. No other phases were detected in the present study, in which the system was always carbon saturated. The thermal expansion coefficients of all phases have been determined, they are constant throughout the temperature interval studied.

  6. The effects of aluminum or scandium on the toughness, density and ...

    African Journals Online (AJOL)

    The effects of the substitution of aluminum or scandium on the density, toughness as well as the stability of the phases formed by such an addition on platinum, iridium, rhodium and palladium metals were evaluated with the density functional quantum mechanical calculation methods. All the metals had four atoms per ...

  7. Effects of erbium‑and chromium‑doped yttrium scandium gallium ...

    African Journals Online (AJOL)

    2014-08-21

    Aug 21, 2014 ... surfaces because of its high power, and the ablation was deeper for these samples. High‑magnification SEM ... Key words: Erbium chromium‑doped yttrium scandium gallium garnet, diode laser, restorative dental materials, scanning electron ... garnet (Nd: YAG) and carbon dioxide (CO2) lasers on indirect ...

  8. A gallium phosphide high-temperature bipolar junction transistor

    Science.gov (United States)

    Zipperian, T. E.; Dawson, L. R.; Chaffin, R. J.

    1981-01-01

    Preliminary results are reported on the development of a high temperature (350 C) gallium phosphide bipolar junction transistor (BJT) for geothermal and other energy applications. This four-layer p(+)n(-)pp(+) structure was formed by liquid phase epitaxy using a supercooling technique to insure uniform nucleation of the thin layers. Magnesium was used as the p-type dopant to avoid excessive out-diffusion into the lightly doped base. By appropriate choice of electrodes, the device may also be driven as an n-channel junction field-effect transistor. The initial design suffers from a series resistance problem which limits the transistor's usefulness at high temperatures.

  9. Gallium Phosphide as a material for visible and infrared optics

    Directory of Open Access Journals (Sweden)

    Václavík J.

    2013-05-01

    Full Text Available Gallium phosphide is interesting material for optical system working in both visible and MWIR or LWIR spectral ranges. Number of a material available for these applications is limited. They are typically salts, fluorides or sulphides and usually exhibit unfavorable properties like brittleness; softness; solubility in water and small chemical resistance. Although GaP has do not offer best optical parameters excels over most other material in mechanical and chemical resistance. The article describes its most important characteristics and outlines some applications where GaP should prove useful.

  10. Clinical characteristics of zinc phosphide poisoning in Thailand

    Directory of Open Access Journals (Sweden)

    Trakulsrichai S

    2017-03-01

    Full Text Available Satariya Trakulsrichai,1,2 Natcha Kosanyawat,1 Pongsakorn Atiksawedparit,1 Charuwan Sriapha,2 Achara Tongpoo,2 Umaporn Udomsubpayakul,3 Panee Rittilert,2 Winai Wananukul2 1Department of Emergency Medicine, 2Ramathibodi Poison Center, 3Section for Clinical Epidemiology and Biostatistics, Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand Objective: The objectives of this study were to describe the clinical characteristics and outcomes of poisoning by zinc phosphide, a common rodenticide in Thailand, and to evaluate whether these outcomes can be prognosticated by the clinical presentation. Materials and methods: A 3-year retrospective cohort study was performed using data from the Ramathibodi Poison Center Toxic Exposure Surveillance System. Results: In total, 455 poisonings were identified. Most were males (60.5% and from the central region of Thailand (71.0%. The mean age was 39.91±19.15 years. The most common route of exposure was oral (99.3%. Most patients showed normal vital signs, oxygen saturation, and consciousness at the first presentation. The three most common clinical presentations were gastrointestinal (GI; 68.8%, cardiovascular (22.0%, and respiratory (13.8% signs and symptoms. Most patients had normal blood chemistry laboratory results and chest X-ray findings at presentation. The median hospital stay was 2 days, and the mortality rate was 7%. Approximately 70% of patients underwent GI decontamination, including gastric lavage and a single dose of activated charcoal. In all, 31 patients were intubated and required ventilator support. Inotropic drugs were given to 4.2% of patients. Four moribund patients also received hyperinsulinemia–euglycemia therapy and intravenous hydrocortisone; however, all died. Patients who survived and died showed significant differences in age, duration from taking zinc phosphide to hospital presentation, abnormal vital signs at presentation (tachycardia

  11. Chemical and biological evaluation of scandium(III)-polyaminopolycarboxylate complexes as potential PET agents and radiopharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    Huclier-Markai, S.; Sabatie, A.; Ribet, S. [Univ. de Nantes (France). Lab. Subatech; Kubicek, V.; Hermann, P. [Charles Univ., Prague (Czech Republic). Dept. of Inorganic Chemistry; Paris, M. [Univ. de Nantes (France). Inst. des Materiaux; Vidaud, C. [CEA/DSV/iBEB/SBTN, Bagnols sur Ceze (France). Lab. d' Etude des Proteines Cibles; Cutler, C.S. [Univ. of Missouri, Columbia, MO (United States). Reserach Reactor Center

    2011-07-01

    Scandium isotopes ({sup 44}Sc, {sup 47}Sc) are more available and their properties are convenient for either PET imaging or radiotherapy. To use them in nuclear medicine, ligands forming complexes with a high stability are necessary. Available experimental data on stability constants for complexes of ligands such as EDTA, DTPA, DOTA, NOTA and TETA with various metal ions have been published. But scandium is the exception since scarce data is available in the literature. Values of stability constants of Sc(III) with the ligands were determined by free-ion selective radiotracer extraction, complemented by {sup 45}Sc NMR and potentiometry data. The thermodynamic stability of the Sc-complexes increases in the order TETA < NOTA < EDTA < DTPA < DOTA. The in vitro stability of the Sc(III) complexes was studied in the presence of hydroxyapatite and rat serum to estimate their in vivo stability. The most stable complex was shown to be Sc-DOTA.

  12. Precipitation behaviour and recrystallisation resistance in aluminum alloys with additions of hafnium, scandium and zirconium

    OpenAIRE

    Hallem, Håkon

    2005-01-01

    The overall objective of this work has been to develop aluminium alloys, which after hot and cold deformation are able to withstand high temperatures without recrystallising. This has been done by investigating aluminium alloys with various additions of hafnium, scandium and zirconium, with a main focus on Hf and to which extent it may partly substitute or replace Zr and/or Sc as a dispersoid forming elements in these alloys. What is the effect of hafnium, alone and in combination with Zr...

  13. Successful Treatment of Severe Metabolic Acidosis Due to Acute Aluminum Phosphide Poisoning With Peritoneal Dialysis: a Report of 2 Cases.

    Science.gov (United States)

    Bashardoust, Bahman; Farzaneh, Esmaeil; Habibzadeh, Afshin; Seyyed Sadeghi, Mir Salim

    2017-03-01

    Aluminum phosphide poisoning is common in our region. It can cause severe metabolic acidosis and persistent hypotension, which lead to cardiogenic shock and subsequently mortality. Oliguric or anuric acute kidney injury is seen in almost all patients with aluminum phosphide poisoning. Renal replacement therapies are recommended in these patients to improve metabolic acidosis and increase the rate of survival. We report 2 cases of severe acute aluminum phosphide poisoning treated successfully with peritoneal dialysis.

  14. Pilot-scale recovery of rare earths and scandium from phosphogypsum and uranium leachates

    Directory of Open Access Journals (Sweden)

    Mashkovtsev Maxim

    2016-01-01

    Full Text Available Ural Federal University (UrFU and VTT have performed joint research on development of industrial technologies for the extraction of REM and Scandium compounds from phosphogypsum and Uranium ISL leachate solutions. Leaching-absorption experiments at UrFU have been supported with multicomponent solution modelling by VTT. The simulations have been performed with VTT’s ChemSheet/Balas program and can be used for speciation calculations in the lixiviant solution. The experimental work combines solvent extraction with advanced ion exchange methodology in a pilot facility capable of treating 5 m3 solution per hour. Currently, the plant produces cerium carbonate, lanthanum oxide, neodymium oxide and concentrate of heavy rare earth metals. A batch of 45 t solids has been processed with the gain of 100 kg’s of REM concentrate. A mini-pilot plant with productivity above 50 liters per hour has been applied to recover scandium oxide and REE concentrates from the uranium ISL solution. As the preliminary product contains radioactivity (mainly strontium, an additional decontamination and cleaning of both concentrates by extraction has rendered a necessity. Finally a purified 99% concentrate of scandium oxide as well as 99% rare earth concentrate are received.

  15. Optimization of scandium oxide growth by high pressure sputtering on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Feijoo, P.C., E-mail: pedronska@fis.ucm.es; Pampillon, M.A.; San Andres, E.; Lucia, M.L.

    2012-12-30

    This work demonstrates the viability of scandium oxide deposition on silicon by means of high pressure sputtering. Deposition pressure and radio frequency power are varied for optimization of the properties of the thin films and the ScO{sub x}/Si interface. The physical characterization was performed by ellipsometry, Fourier transform infrared spectroscopy, x-ray diffraction and transmission electron microscopy. Aluminum gate electrodes were evaporated for metal-insulator-semiconductor (MIS) fabrication. From the electrical characterization of the MIS devices, the density of interfacial defects is found to decrease with deposition pressure, showing a reduced plasma damage of the substrate surface for higher pressures. This is also supported by lower flatband voltage shifts in the capacitance versus voltage hysteresis curves. Sputtering at high pressures (above 100 Pa) reduces the interfacial SiO{sub x} formation, according to the infrared spectra. The growth rates decrease with deposition pressure, so a very accurate control of the layer thicknesses could be provided. - Highlights: Black-Right-Pointing-Pointer Scandium oxide is considered as a high permittivity dielectric. Black-Right-Pointing-Pointer Scandium oxide was deposited on Si by high pressure sputtering. Black-Right-Pointing-Pointer Characterization was performed for deposition condition optimization. Black-Right-Pointing-Pointer High deposition pressures showed higher film and interface quality.

  16. Optical properties of indium phosphide nanowire ensembles at various temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Lohn, Andrew J; Onishi, Takehiro; Kobayashi, Nobuhiko P [Baskin School of Engineering, University of California Santa Cruz, Santa Cruz, CA 95064 (United States); Nanostructured Energy Conversion Technology and Research (NECTAR), Advanced Studies Laboratories, University of California Santa Cruz-NASA Ames Research Center, Moffett Field, CA 94035 (United States)

    2010-09-03

    Ensembles that contain two types (zincblende and wurtzite) of indium phosphide nanowires grown on non-single crystalline surfaces were studied by micro-photoluminescence and micro-Raman spectroscopy at various low temperatures. The obtained spectra are discussed with the emphasis on the effects of differing lattice types, geometries, and crystallographic orientations present within an ensemble of nanowires grown on non-single crystalline surfaces. In the photoluminescence spectra, a typical Varshni dependence of band gap energy on temperature was observed for emissions from zincblende nanowires and in the high temperature regime energy transfer from excitonic transitions and band-edge transitions was identified. In contrast, the photoluminescence emissions associated with wurtzite nanowires were rather insensitive to temperature. Raman spectra were collected simultaneously from zincblende and wurtzite nanowires coexisting in an ensemble. Raman peaks of the wurtzite nanowires are interpreted as those related to the zincblende nanowires by a folding of the phonon dispersion.

  17. AC surface photovoltage of indium phosphide nanowire networks

    Energy Technology Data Exchange (ETDEWEB)

    Lohn, Andrew J.; Kobayashi, Nobuhiko P. [California Univ., Santa Cruz, CA (United States). Baskin School of Engineering; California Univ., Santa Cruz, CA (US). Nanostructured Energy Conversion Technology and Research (NECTAR); NASA Ames Research Center, Moffett Field, CA (United States). Advanced Studies Laboratories

    2012-06-15

    Surface photovoltage is used to study the dynamics of photogenerated carriers which are transported through a highly interconnected three-dimensional network of indium phosphide nanowires. Through the nanowire network charge transport is possible over distances far in excess of the nanowire lengths. Surface photovoltage was measured within a region 10.5-14.5 mm from the focus of the illumination, which was chopped at a range of frequencies from 15 Hz to 30 kHz. Carrier dynamics were modeled by approximating the nanowire network as a thin film, then fitted to experiment suggesting diffusion of electrons and holes at approximately 75% of the bulk value in InP but with significantly reduced built-in fields, presumably due to screening by nanowire surfaces. (orig.)

  18. Indium Phosphide-Based Semiconductor Nanocrystals and Their Applications

    Directory of Open Access Journals (Sweden)

    Paul Mushonga

    2012-01-01

    Full Text Available Semiconductor nanocrystals or quantum dots (QDs are nanometer-sized fluorescent materials with optical properties that can be fine-tuned by varying the core size or growing a shell around the core. They have recently found wide use in the biological field which has further enhanced their importance. This review focuses on the synthesis of indium phosphide (InP colloidal semiconductor nanocrystals. The two synthetic techniques, namely, the hot-injection and heating-up methods are discussed. Different types of the InP-based QDs involving their use as core, core/shell, alloyed, and doped systems are reviewed. The use of inorganic shells for surface passivation is also highlighted. The paper is concluded by some highlights of the applications of these systems in biological studies.

  19. Fabrication and properties of gallium phosphide variable colour displays

    Science.gov (United States)

    Effer, D.; Macdonald, R. A.; Macgregor, G. M.; Webb, W. A.; Kennedy, D. I.

    1973-01-01

    The unique properties of single-junction gallium phosphide devices incorporating both red and green radiative recombination centers were investigated in application to the fabrication of monolithic 5 x 7 displays capable of displaying symbolic and alphanumeric information in a multicolor format. A number of potentially suitable material preparation techniques were evaluated in terms of both material properties and device performance. Optimum results were obtained for double liquid-phase-epitaxial process in which an open-tube dipping technique was used for n-layer growth and a sealed tipping procedure for subsequent p-layer growth. It was demonstrated that to prepare devices exhibiting a satisfactory range of dominant wavelengths which can be perceived as distinct emission colors extending from the red through green region of the visible spectrum involves a compromise between the material properties necessary for efficient red emission and those considered optimum for efficient green emission.

  20. Deoxygenation of Palmitic Acid on Unsupported Transition-Metal Phosphides

    Energy Technology Data Exchange (ETDEWEB)

    Peroni, Marco [Technische Universität München, Department; Lee, Insu [Technische Universität München, Department; Huang, Xiaoyang [Technische Universität München, Department; Baráth, Eszter [Technische Universität München, Department; Gutiérrez, Oliver Y. [Technische Universität München, Department; Lercher, Johannes A. [Technische Universität München, Department; Institute

    2017-08-18

    Abstract Highly active bulk transition metal phosphides (WP, MoP, and Ni2P) were synthesized for the catalytic hydrodeoxygenation of palmitic acid, hexadecanol, hexadecanal, and microalgae oil. The specific activities positively correlated with the concentration of exposed metal sites, although the relative rates changed with temperature due to activation energies varying from 57 kJ·mol-1 for MoP to 142 kJ·mol-1 for WP. The reduction of the fatty acid to the aldehyde occurs through a Langmuir-Hinshelwood mechanism, where the rate-determining step is the addition of the second H to the hydrocarbon. On WP, the conversion of palmitic acid proceeds via R-CH2COOH R-CH2CHO R-CH2CH2OH R-CHCH2 R-CH2CH3 (hydrodeoxygenation). Decarbonylation of the intermittently formed aldehyde (R-CH2COOH R-CH2CHO R-CH3) was an important pathway on MoP and Ni2P. Conversion via dehydration to a ketene, followed by its decarbonylation occurred only on Ni2P. The rates of alcohol dehydration (R-CH2CH2OH R-CHCH2) correlate with the concentration of Lewis acid sites of the phosphides. Acknowledgements The authors would like to thank Roel Prins for the critical discussion of the results. We are also grateful to Xaver Hecht for technical support. Funding by the German Federal Ministry of Food and Agriculture in the framework of the Advanced Biomass Value project (03SF0446A) is gratefully acknowledged. J.A.L. acknowledges support for his contribution by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences for exploring non-oxidic supports for deoxygenation reactions.

  1. Initial Stages in the Formation of Nickel Phosphides.

    Science.gov (United States)

    García-Muelas, Rodrigo; Li, Qiang; López, Núria

    2017-09-25

    Metal phosphides have emerged as a new powerful class of materials that can be employed as heterogeneous catalysts in transformations mainly to generate new energy vectors and the valorization of renewables. Synthetic protocols based on wet techniques are available and are based on the decomposition of the organic layer decorating the nanoparticles. For nickel, the phosphine of choice is trioctylphosphine, and this leads to the formation of NiPx materials. However, the temperature at which the decomposition starts has been found to depend on the quality of the nickel surface. Density functional theory, DFT, holds the key to analyze the initial steps of the formation of these phosphide materials. We have found how clean nickel surfaces, either (111) or (100), readily breaks the ligand P-C bonds. This triggers the process that leads to the replacement of a surface nickel atom by P and concomintantly forms a Ni adatom on the surface surrounded by two methyl groups, thus starting the formation of the NiPx phase. The whole process requires low energies, in agreement with the low temperature found in the experiments, 150 °C. In contrast, if the surface is oxidized, the reaction does not proceed at low temperatures and oxygen vacancies need to be created first to start the P-C bond breaking on the Ni-clean patches. Our results show that the cleaner the surface is, the milder the reactions are required for the NiPx formation, and thus they pave the way for gentler synthetic protocols that can improve the control of these materials.

  2. Recovery of Scandium from Leachate of Sulfation-Roasted Bayer Red Mud by Liquid-Liquid Extraction

    Science.gov (United States)

    Liu, Zhaobo; Li, Hongxu; Jing, Qiankun; Zhang, Mingming

    2017-11-01

    The leachate obtained from sulfation-roasted Bayer red mud is suitable for extraction of scandium by liquid-liquid solvent extraction because it contains trace amounts of Fe3+ and Si4+. In this study, a completely new metallurgical process for selective recovery of scandium from Bayer red mud was proposed. The extraction performances of Sc3+, Fe3+, Al3+, Si4+, Ca2+, and Na+ from synthetic leachate of sulfation-roasted red mud were first investigated using organophosphorus extractants (di-2-ethylhexyl phosphoric acid P204 and 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester P507) and carboxylic acid extractant (Versatic acid 10). It shows that P204 has an excellent extraction ability and that it can be applied to the scandium recovery. P507 and Versatic acid 10 are much poorer in performance for selective extraction of scandium. In the leachate of sulfation-roasted red mud, approximately 97% scandium can be recovered using a P204/sulfonated kerosene (1% v/v) extraction system under the condition of an organic-to-aqueous phase ratio of 10:1 and with an extraction temperature of 15°C.

  3. Andreyivanovite: A Second New Phosphide from the Kaidun Meteorite

    Science.gov (United States)

    Zolensky, Michael

    2008-01-01

    Andreyivanovite (ideally FeCrP) is another new phosphide species from the Kaidun meteorite, which fell in South Yemen in 1980. Kaidun is a unique breccia containing an unprecedented variety of fragments of different chondritic as well as achondritic lithologies. Andreyivanovite was found as individual grains and linear arrays of grains with a maximum dimension of 8 m within two masses of Fe-rich serpentine. In one sample it is associated with Fe-Ni-Cr sulfides and florenskyite (FeTiP). Andreyivanovite is creamy white in reflected light, and its luster is metallic. The average of nine electron microprobe analyses yielded the formula Fe(Cr0.587 Fe0.150 V0.109 Ti0.081 Ni0.060 Co0.002)P. Examination of single grains of andreyivanovite using Laue patterns collected by in-situ synchrotron X-ray diffraction (XRD), and by electron backscattered diffraction revealed that it is isostructural with florenskyite; we were unable to find single crystals of sufficient quality to perform a complete structure analysis. Andreyivanovite crystallizes in the space group Pnma, and has the anti-PbCl2 structure. Previously-determined cell constants of synthetic material [a = 5.833(1), b = 3.569(1), c = 6.658(1) A] were consistent with our XRD work. We used the XPOW program to calculate a powder XRD pattern; the 5 most intense reflections are d = 2.247 (I = 100), 2.074 (81), 2.258 (46), 1.785 (43), and 1.885 A (34). Andreyivanovite is the second new phosphide to be described from the Kaidun meteorite. Andreyivanovite could have formed as a result of cooling and crystallization of a melted precursor consisting mainly of Fe-Ni metal enriched in P, Ti, and Cr. Serpentine associated with andreyivanovite would then have formed during aqueous alteration on the parent asteroid. It is also possible that the andreyivanovite could have formed during aqueous alteration, however, artificial FeTiP has been synthesized only during melting experiments, at low oxygen fugacity, and there is no evidence that

  4. MOF-Derived Cobalt Phosphide/Carbon Nanocubes for Selective Hydrogenation of Nitroarenes to Anilines.

    Science.gov (United States)

    Yang, Shuliang; Peng, Li; Oveisi, Emad; Bulut, Safak; Sun, Daniel T; Asgari, Mehrdad; Trukhina, Olga; Queen, Wendy L

    2017-12-19

    Transition-metal phosphides have received tremendous attention during the past few years because they are earth-abundant, cost-effective, and show outstanding catalytic performance in several electrochemically driven conversions including hydrogen evolution, oxygen evolution, and water splitting. As one member of the transition-metal phosphides, Co x P-based materials have been widely explored as electrocatalyts; however, their application in the traditional thermal catalysis are rarely reported. In this work, cobalt phosphide/carbon nanocubes are designed and their catalytic activity for the selective hydrogenation of nitroarenes to anilines is studied. A high surface area metal-organic framework (MOF), ZIF-67, is infused with red phosphorous, and then pyrolysis promotes the facile production of the phosphide-based catalysts. The resulting composite, consisting of Co 2 P/CN x nanocubes, is shown to exhibit excellent catalytic performance in the selective hydrogenation of nitroarenes to anilines. To the best of our knowledge, this is the first report showing catalytic activity of a cobalt phosphide in nitroarenes hydrogenation. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Synthesis and catalytic activity of the metastable phase of gold phosphide

    Energy Technology Data Exchange (ETDEWEB)

    Fernando, Deshani; Nigro, Toni A. E.; Dyer, I. D.; Alia, Shaun M.; Pivovar, Bryan S.; Vasquez, Yolanda

    2016-10-01

    Recently, transition metal phosphides have found new applications as catalysts for the hydrogen evolution reaction that has generated an impetus to synthesize these materials at the nanoscale. In this work, Au2P3 was synthesized utilizing the high temperature decomposition of tri-n-octylphosphine as a source of elemental phosphorous. Gold nanorods were used as morphological templates with the aim of controlling the shape and size of the resulting gold phosphide particles. We demonstrate that the surface capping ligand of the gold nanoparticle precursors can influence the purity and extent to which the gold phosphide phase will form. Gold nanorods functionalized with 1-dodecanethiol undergo digestive ripening to produce discrete spherical particles that exhibit reduced reactivity towards phosphorous, resulting in low yields of the gold phosphide. In contrast, gold phosphide was obtained as a phase pure product when cetyltrimethylammonium bromide functionalized gold nanorods are used instead. The Au2P3 nanoparticles exhibited higher activity than polycrystalline gold towards the hydrogen evolution reaction.

  6. Scandium-doped zinc cadmium oxide as a new stable n-type oxide thermoelectric material

    DEFF Research Database (Denmark)

    Han, Li; Christensen, Dennis Valbjørn; Bhowmik, Arghya

    2016-01-01

    Scandium-doped zinc cadmium oxide (Sc-doped ZnCdO) is proposed as a new n-type oxide thermoelectric material. The material is sintered in air to maintain the oxygen stoichiometry and avoid instability issues. The successful alloying of CdO with ZnO at a molar ratio of 1 : 9 significantly reduced...... is a good candidate for improving the overall conversion efficiencies in oxide thermoelectric modules. Meanwhile, Sc-doped ZnCdO is robust in air at high temperatures, whereas other n-type materials, such as Al-doped ZnO, will experience rapid degradation of their electrical conductivity and ZT....

  7. 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.

  8. Thermal Properties and Phonon Spectral Characterization of Synthetic Boron Phosphide for High Thermal Conductivity Applications.

    Science.gov (United States)

    Kang, Joon Sang; Wu, Huan; Hu, Yongjie

    2017-12-13

    Heat dissipation is an increasingly critical technological challenge in modern electronics and photonics as devices continue to shrink to the nanoscale. To address this challenge, high thermal conductivity materials that can efficiently dissipate heat from hot spots and improve device performance are urgently needed. Boron phosphide is a unique high thermal conductivity and refractory material with exceptional chemical inertness, hardness, and high thermal stability, which holds high promises for many practical applications. So far, however, challenges with boron phosphide synthesis and characterization have hampered the understanding of its fundamental properties and potential applications. Here, we describe a systematic thermal transport study based on a synergistic synthesis-experimental-modeling approach: we have chemically synthesized high-quality boron phosphide single crystals and measured their thermal conductivity as a record-high 460 W/mK at room temperature. Through nanoscale ballistic transport, we have, for the first time, mapped the phonon spectra of boron phosphide and experimentally measured its phonon mean free-path spectra with consideration of both natural and isotope-pure abundances. We have also measured the temperature- and size-dependent thermal conductivity and performed corresponding calculations by solving the three-dimensional and spectral-dependent phonon Boltzmann transport equation using the variance-reduced Monte Carlo method. The experimental results are in good agreement with that predicted by multiscale simulations and density functional theory, which together quantify the heat conduction through the phonon mode dependent scattering process. Our finding underscores the promise of boron phosphide as a high thermal conductivity material for a wide range of applications, including thermal management and energy regulation, and provides a detailed, microscopic-level understanding of the phonon spectra and thermal transport mechanisms of

  9. Characterization of Gallium Indium Phosphide and Progress of Aluminum Gallium Indium Phosphide System Quantum-Well Laser Diode

    Science.gov (United States)

    Hamada, Hiroki

    2017-01-01

    Highly ordered gallium indium phosphide layers with the low bandgap have been successfully grown on the (100) GaAs substrates, the misorientation toward [01−1] direction, using the low-pressure metal organic chemical vapor deposition method. It is found that the optical properties of the layers are same as those of the disordered ones, essentially different from the ordered ones having two orientations towards [1−11] and [11−1] directions grown on (100) gallium arsenide substrates, which were previously reported. The bandgap at 300 K is 1.791 eV. The value is the smallest ever reported, to our knowledge. The high performance transverse stabilized AlGaInP laser diodes with strain compensated quantum well structure, which is developed in 1992, have been successfully obtained by controlling the misorientation angle and directions of GaAs substrates. The structure is applied to quantum dots laser diodes. This paper also describes the development history of the quantum well and the quantum dots laser diodes, and their future prospects. PMID:28773227

  10. Development of a Free Carrier Absorption Measurement Instrument for Indium Phosphide and Gallium Arsenide.

    Science.gov (United States)

    1986-10-27

    AD-A174 ř DEVELOPMENT OF R FREE CARRIER ABSORPTION MEASUREMENT 1/2 INSTRUMENT FOR INDTU (U) EAGLE-PICHER RESEARCH LAB MIAMI OK SPECIALTY MATERIALS...SOBI S D Final Report Development of a Free Carrier Absorption Measurement Instrument For Indium Phosphide and Gallium Arsenide EAGLE PICHER R ES EA R CH...i P r OTic S D L C T DEC 0 3 ang Final Report Development of a Free Carrier Absorption Measurement Instrument For Indium Phosphide and Gallium

  11. A CASE REPORT ON ZINC PHOSPHIDE POISONING AND ITS RARE EFFECTS

    Directory of Open Access Journals (Sweden)

    Naga Raghunandan Thota

    2017-02-01

    Full Text Available BACKGROUND Zinc phosphide is widely in use as a rodenticide. After ingestion, it gets converted to phosphine gas, which is subsequently absorbed into the bloodstream through the stomach and the intestines and gets captured by the liver and the lungs. The toxic effects of zinc phosphide poisoning is through the phosphine gas that produces various metabolic and non-metabolic intermediate compounds. Patients develop features of shock, myocarditis, pericarditis, acute pulmonary oedema and congestive heart failure. In this case report, we present a common complication of the poison that manifested earlier than it is depicted in the current literature.

  12. Scandium and yttrium phosphasalen complexes as initiators for ring-opening polymerization of cyclic esters.

    Science.gov (United States)

    Bakewell, Clare; White, Andrew J P; Long, Nicholas J; Williams, Charlotte K

    2015-03-02

    The synthesis and characterization of novel scandium and yttrium phosphasalen complexes is reported, where phosphasalen refers to two different bis(iminophosphorane) derivatives of the more ubiquitous salen ligands. The activity of the complexes as initiators for the ring-opening polymerization of cyclic esters is presented. The scandium complexes are inactive for lactide polymerization but slow and controlled initiators for ε-caprolactone polymerization. The lack of activity toward lactide exhibited by these compounds is probed, and a rare example of single-monomer insertion product, unable to undergo further reactions with lactide, is identified. In contrast, the analogous yttrium phosphasalen complex is a very active initiator for the ring-opening polymerization of rac-lactide (kobs = 1.5 × 10(-3) s(-1) at 1:500 [yttrium initiator]:[rac-lactide], 1 M overall concentration of lactide in THF at 298 K). In addition to being a very fast initiator, the yttrium complex also maintains excellent levels of polymerization control and a high degree of isoselectivity, with the probability of isotactic enchainment being Pi = 0.78 at 298 K.

  13. Thermodynamic parameters of scandium trifluoride and triiodide in the condensed state

    Science.gov (United States)

    Aristova, N. M.; Belov, G. V.

    2015-06-01

    The thermodynamic properties of new classes of compounds, particularly scandium trihalides ScF3, ScCl3, ScBr3, and ScI3, are added to the IVTANTHERMO software package. A critical analysis and processing of the entire array of primary data available in the literature is performed. An equation approximating the temperature dependence of heat capacity in the temperature range 298.15- T m (K) is derived for each crystalline scandium trihalide. The resulting equations C {/p po}( T) for the solid state and the data for the liquid phase are used to calculate the thermodynamic functions of entropy, the reduced Gibbs free energies, and the enthalpy increments. Both the experimental data available in literature and the missing estimated thermodynamic data are used in calculations. The error of the recommended values is estimated in all cases. In the first part of this work, we describe the thermodynamic properties of ScF3 and ScI3 used as the reference data for calculating the thermodynamic functions of ScCl3 and ScBr3, for which experimental data are either very scarce or missing altogether. The resulting data are added to the database of the IVTANTHERMO software package.

  14. Frequency of Cardiac Arrhythmias in Patients with Aluminum Phosphide Poisoning

    Directory of Open Access Journals (Sweden)

    Umair Aziz

    2015-12-01

    Full Text Available Background: Cardiac failure is the major lethal consequence of aluminum phosphide (AlP poisoning. This study was designed to determine the frequency of cardiac arrhythmias in patients with AlP poisoning. Methods: In this prospective cross-sectional study, patients with definitive history of AlP poisoning treated at emergency department of Allied Hospital Faisalabad, Faisalabad, Pakistan, from July 2013 to November 2014 were included. On admission, twelve-lead electrocardiogram (ECG was performed for all patients. During admission, all patients underwent continuous cardiac monitoring using a cardiac monitor. If an arrhythmia was suspected on the cardiac monitor, another ECG was obtained immediately.  Results: During the study period, 100 patients with AlP poisoning (63% men were treated at Allied Hospital Faisalabad. Mean age of the patients was 26.7 ± 7.9 years ranging from 16 to 54 years. Tachycardia was detected in 68 patients and bradycardia in 12 patients. Hypotension was observed in 75 patients. Eighty patients developed cardiac arrhythmia. The most frequent arrhythmia was atrial fibrillation (31% of patients followed by ventricular fibrillation (20%, ventricular tachycardia (17%, 3rd degree AV block (7% and 2nd degree AV block (5%. In total, 78 patients died, depicting a 78% mortality rate following wheat pill poisoning. Among those who died, seventy-one patients had cardiac arrhythmia. Comparison of death rate between patients with and without cardiac arrhythmia showed a significant difference (71/80 (88.8% vs. 7/20 (35%; P < 0.001.  Conclusion: Wheat pill poisoning causes a very high mortality, and circulatory collapse is the major cause of death among these patients. Most of the patients with AlP poisoning develop cardiac arrhythmias which are invariably life threatening. Early detection of cardiac disorders and proper management of arrhythmias may reduce mortalities.

  15. Indium Phosphide Window Layers for Indium Gallium Arsenide Solar Cells

    Science.gov (United States)

    Jain, Raj K.

    2005-01-01

    Window layers help in reducing the surface recombination at the emitter surface of the solar cells resulting in significant improvement in energy conversion efficiency. Indium gallium arsenide (In(x)Ga(1-x)As) and related materials based solar cells are quite promising for photovoltaic and thermophotovoltaic applications. The flexibility of the change in the bandgap energy and the growth of InGaAs on different substrates make this material very attractive for multi-bandgap energy, multi-junction solar cell approaches. The high efficiency and better radiation performance of the solar cell structures based on InGaAs make them suitable for space power applications. This work investigates the suitability of indium phosphide (InP) window layers for lattice-matched In(0.53)Ga(0.47)As (bandgap energy 0.74 eV) solar cells. We present the first data on the effects of the p-type InP window layer on p-on-n lattice-matched InGaAs solar cells. The modeled quantum efficiency results show a significant improvement in the blue region with the InP window. The bare InGaAs solar cell performance suffers due to high surface recombination velocity (10(exp 7) cm/s). The large band discontinuity at the InP/InGaAs heterojunction offers a great potential barrier to minority carriers. The calculated results demonstrate that the InP window layer effectively passivates the solar cell front surface, hence resulting in reduced surface recombination and therefore, significantly improving the performance of the InGaAs solar cell.

  16. Wavelength dependence of light diffusion in strongly scattering macroporous gallium phosphide

    NARCIS (Netherlands)

    Peeters, W.H.; Vellekoop, Ivo Micha; Mosk, Allard; Lagendijk, Aart

    2008-01-01

    We present time-resolved measurements of light transport through strongly scattering macroporous gallium phosphide at various vacuum wavelengths between 705 nm and 855 nm. Within this range the transport mean free path is strongly wavelength dependent, whereas the observed energy velocity is shown

  17. Aluminium Phosphide Poisoning: Two Pediatric Patients and Two Different Clinical Outcomes

    Directory of Open Access Journals (Sweden)

    Faruk Ekinci

    2017-08-01

    Full Text Available Aluminium phosphide is an insecticide that turns into a quite toxic gas called phosphine when contacts with gastric fluids. Aluminium phosphide poisoning causes severe metabolic acidosis, acute respiratory distress syndrome and multi-organ failure with cardiogenic shock. Our first case was an-18-year-old girl admitted to our emergency department two hours after ingestion of one tablet containing 500 mg aluminium phosphide in a suicide attempt. Venoarterial extracorporeal membrane oxygenation was started one hour after initiation of inotropic agents. Despite improvement in hemodynamic status, she developed refractory arrhythmias at the12th hour and she died 22 hours after admission. The second case was a two-year-old girl who was admitted to our emergency department because of observing a piece of aluminum phosphide 500 mg tablet broken in her mouth. Her vital signs were stable in the follow-up. The patient who had no problems in the follow-up was discharged at 48 hours.

  18. Effect of aluminium phosphide on some metabolites of the liver and ...

    African Journals Online (AJOL)

    Aluminium phosphide induced changes in some metabolic parameters in Parophiocephalus obscurus were assessed. Parophiocephalus obscurus (mean length, 18.00±0.09cm and mean weight, 65.03±0.03g) were acclimatized to laboratory condition for 10 days and then exposed to varying sublethal concentrations of ...

  19. Low temperature synthesis of ternary metal phosphides using plasma for asymmetric supercapacitors

    KAUST Repository

    Liang, Hanfeng

    2017-04-06

    We report a versatile route for the preparation of metal phosphides using PH plasma for supercapacitor applications. The high reactivity of plasma allows rapid and low temperature conversion of hydroxides into monometallic, bimetallic, or even more complex nanostructured phosphides. These same phosphides are much more difficult to synthesize by conventional methods. Further, we present a general strategy for significantly enhancing the electrochemical performance of monometallic phosphides by substituting extrinsic metal atoms. Using NiCoP as a demonstration, we show that the Co substitution into NiP not only effectively alters the electronic structure and improves the intrinsic reactivity and electrical conductivity, but also stabilizes Ni species when used as supercapacitor electrode materials. As a result, the NiCoP nanosheet electrodes achieve high electrochemical activity and good stability in 1 M KOH electrolyte. More importantly, our assembled NiCoP nanoplates//graphene films asymmetric supercapacitor devices can deliver a high energy density of 32.9 Wh kg at a power density of 1301 W kg, along with outstanding cycling performance (83% capacity retention after 5000 cycles at 20 A g). This activity outperforms most of the NiCo-based materials and renders the NiCoP nanoplates a promising candidate for capacitive storage devices.

  20. Zinc phosphide toxicity with a trial of tranexamic acid in its management

    Directory of Open Access Journals (Sweden)

    Abdel Rahman M. El Naggar

    2011-04-01

    Full Text Available Zinc phosphide is a highly effective rodenticide used widely to protect grain in stores and domestically to kill rodents. Acute poisoning may be direct by ingestion or indirect through accidental inhalation of phosphine gas generated during its use. This study aims to identify the patterns of intoxication with zinc phosphide among Egyptian patients admitted to the National Egyptian Center of Clinical and Environmental Toxicological Research (NECTR; to study the role of antifibrinolytics in management of zinc phosphide toxicity; and to publish the results of the study, which include recommendations for action towards planning prevention and education programs. The study provides descriptive data and analysis of 188 cases admitted to the NECTR with acute zinc phosphide poisoning over a period of 22 months. Results show that poisoning is more common among females (60.6% of cases than males (39.4%; the mean age is nearly 21 years old. The most common cause of poisoning is suicidal attempts (83.6% followed by accidental exposure (16.4%. The most common causative factors that lead to self-poisoning are marital disharmony, economic hardship, social problems and scolding from other family members. Signs and symptoms of toxicity include gastrointestinal disturbances, respiratory compromise and changes in mental status. Other features include disseminated intravascular coagulation, hepatic and renal impairment. Metabolic disturbances had been reported. Death can result immediately due to pulmonary edema or delayed due to cardiotoxicity. Patients must be admitted to hospital and observed for at least 3 days. Symptomatic and supportive care is the mainstay of therapy. Zinc phosphide poisoning requires gastric lavage with excessive sodium bicarbonate solution. Tranexamic acid – an antifibrinolytic agent – was found to be of help in some cases. Psychosocial counseling in cases of intentional poisoning is an important aspect of overall management of the

  1. Recovery of Scandium(III) from Aqueous Solutions by Solvent Extraction with the Functionalized Ionic Liquid Betainium Bis(trifluoromethylsulfonyl)imide

    OpenAIRE

    Onghena, Bieke; Binnemans, Koen

    2015-01-01

    The ionic liquid betainium is(trifluoromethylsulfonyl)imide [Hbet][Tf2N] was used for the extraction of scandium from aqueous solutions. The influence of several extraction parameters on the extraction efficiency was investigated, including the initial metal concentration, phase ratio, and pH. The extraction kinetics was examined, and a comparison was made between conventional liquid−liquid extraction and homogeneous liquid−liquid extraction (HLLE). The stoichiometry of the extracted scandium...

  2. Modification mechanism of eutectic silicon in Al–6Si–0.3Mg alloy with scandium

    Energy Technology Data Exchange (ETDEWEB)

    Patakham, Ussadawut [Manufacturing and Systems Engineering Program, Department of Production Engineering, Faculty of Engineering, King Mongkut’s University of Technology Thonburi, 126 Pracha-Utid Rd., Bangmod, Tungkhru, Bangkok 10140 (Thailand); Kajornchaiyakul, Julathep [National Metal and Material Technology Center, National Science and Technology Development Agency, 114 Thailand Science Park, Klong Nueng, Klong Luang, Pathumthani 12120 (Thailand); Limmaneevichitr, Chaowalit, E-mail: chaowalit.lim@kmutt.ac.th [Manufacturing and Systems Engineering Program, Department of Production Engineering, Faculty of Engineering, King Mongkut’s University of Technology Thonburi, 126 Pracha-Utid Rd., Bangmod, Tungkhru, Bangkok 10140 (Thailand)

    2013-10-25

    Highlights: •Morphologies and growth of Sc and Sr-modified eutectic silicon resemble those of dendrites. •Crystal orientation of eutectic aluminum depends on growth characteristics of eutectic silicon. •We report strong evidence of the occurrence of an impurity-induced twinning mechanism. -- Abstract: The modification mechanism of eutectic silicon in Al–6Si–0.3Mg alloy with scandium was studied. The crystallographic orientation relationships between primary dendrites and the eutectic phase of unmodified and modified Al–6Si–0.3 Mg alloys were determined using electron backscatter diffraction (EBSD). The orientation of aluminum modified with scandium in the eutectic phase was different from that of the neighboring primary dendrites. This result implies that eutectic aluminum grows epitaxially from the surrounding primary aluminum dendrites in the unmodified alloy and that eutectic aluminum grows competitively from the surrounding primary aluminum dendrites in the modified alloy. The pole figure maps of eutectic Si in the [1 0 0], [1 1 0] and [1 1 1] axes of the unmodified and Sc-modified alloys were different, suggesting that the eutectic Al and Si crystals in modified alloy growth are more isotropic and cover a larger set of directions. The lattice fringes of Si of the alloys with and without Sc modification were different in the TEM results. The lattice fringes of Si in modified alloy were found to be multiple twins. However, this was not observed in the unmodified alloy. The growth characteristic of eutectic Si crystal in modified alloy suggests the occurrence of multiple twinning reactions and the formation of a high density of twins. This modification mechanism by Sc is explained by the results of scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) analysis, which provide strong evidence of the occurrence of the impurity-induced twinning (IIT) mechanism.

  3. Grain refinement mechanism in an Al-Si-Mg alloy with scandium

    Energy Technology Data Exchange (ETDEWEB)

    Patakham, Ussadawut [Department of Production Engineering, Faculty of Engineering, King Mongkut' s University of Technology Thonburi, 126 Pracha-Utid Rd., Bangmod, Tungkhru, Bangkok 10140 (Thailand); Kajornchaiyakul, Julathep [National Metal and Material Technology Center, National Science and Technology Development Agency, 114 Thailand Science Park, Klong Nueng, Klong Luang, Pathumthani 12120 (Thailand); Limmaneevichitr, Chaowalit, E-mail: chaowalit.lim@kmutt.ac.th [Department of Production Engineering, Faculty of Engineering, King Mongkut' s University of Technology Thonburi, 126 Pracha-Utid Rd., Bangmod, Tungkhru, Bangkok 10140 (Thailand)

    2012-11-25

    Highlights: Black-Right-Pointing-Pointer Scandium can be used to refine aluminum grains in an Al-Si-Mg aluminum alloy. Black-Right-Pointing-Pointer The effectiveness of Sc is lower than that of conventional Al-Ti grain refiners. Black-Right-Pointing-Pointer Al{sub 3}Sc particles can act as heterogeneous nuclei of aluminum phases. Black-Right-Pointing-Pointer Higher alloying elements cause more intermetallic compound phases. Black-Right-Pointing-Pointer Those phases cannot effectively act as heterogeneous nuclei compared with Al{sub 3}Sc particles. - Abstract: Grain refinement of the primary aluminum ({alpha}-Al) phase in a hypoeutectic Al-Si alloy using scandium (Sc) was studied to identify the grain refinement mechanism. Optical microscopy (OM), Scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and electron backscatter diffraction (EBSD) techniques were extensively used in this study. We found that Sc refined grains of primary aluminum. However, the grain refinement efficiency of Sc was considerably lower than that of titanium (Ti) in the Al-Si-Mg foundry alloy. It was evident that the precipitated Sc-containing phases acted as heterogeneous nucleation sites for the primary aluminum phase. The Sc-containing heterogeneous sites are irregular in shape with sizes between 3 and 5 {mu}m. At least three groups of nuclei based on their chemical composition were found, i.e., (i) Al and Sc, (ii) Al, Si, Mg, and Sc, and (iii) Al, Si, Mg, Sc, and Fe. Crystal orientation mapping showed primary aluminum dendrites with one orientation in each grain near Al{sub 3}Sc particles. The grain refinement mechanism of Sc for aluminum relies on heterogeneous nucleation of Al{sub 3}Sc particles, with less responsibly for grain growth restriction. Many intermetallic phases with Al, Si, Fe, Mg and Sc as their major components were found, and these phases could not effectively act as heterogeneous nuclei.

  4. Neutron and Charged-Particle Induced Cross Sections for Radiochemistry for Isotopes of Scandium, Titanium, Vanadium, Chromium, Manganese, and Iron

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, K; Hoffman, R D; Dietrich, F S; Bauer, R; Mustafa, M

    2004-11-30

    We have developed a set of modeled nuclear reaction cross sections for use in radiochemical diagnostics. Local systematics for the input parameters required by the Hauser-Feshbach statistical model were developed and used to calculate neutron and proton induced nuclear reaction cross sections in the mass region of scandium, titanium, vanadium, chromium, manganese, and iron (21 {le} Z {le} 26, 20 {le} N {le} 32).

  5. A composite cathode based on scandium doped titanate with enhanced electrocatalytic activity towards direct carbon dioxide electrolysis.

    Science.gov (United States)

    Yang, Liming; Xie, Kui; Wu, Lan; Qin, Qingqing; Zhang, Jun; Zhang, Yong; Xie, Ting; Wu, Yucheng

    2014-10-21

    A composite cathode based on redox-stable La0.2Sr0.8TiO(3+δ) (LSTO) can perform direct carbon dioxide electrolysis; however, the insufficient electro-catalytic activity limits the electrode performances and current efficiencies. In this work, catalytically active scandium is doped into LSTO to enhance the electro-catalytic activity for CO2 electrolysis. The structures, electronic conductivities and ionic conductivities of La0.2Sr0.8Ti(1-x)Sc(x)O (LSTS(x)O) (x = 0, 0.05, 0.1, 0.15 and 0.2) are systematically studied and further correlated with electrode performances. The ionic conductivities of single-phase LSTS(x)O (x = 0, 0.05, 0.1 and 0.15) remarkably improve versus the scandium doping contents though the electrical conductivities gradually change in an adverse trend. Electrochemical measurements demonstrate promising electrode polarisation of LSTS(x)O electrodes and increasing scandium doping contents accordingly improve electrode performances. The Faradic efficiencies of carbon dioxide electrolysis are enhanced by 20% with LSTS0.15O in contrast to bare LSTO electrodes in a solid oxide electrolyser at 800 °C.

  6. Theoretical Study on Electronic, Optical Properties and Hardness of Technetium Phosphides under High Pressure

    Directory of Open Access Journals (Sweden)

    Shiquan Feng

    2017-06-01

    Full Text Available In this paper, the structural properties of technetium phosphides Tc3P and TcP4 are investigated by first principles at zero pressure and compared with the experimental values. In addition, the electronic properties of these two crystals in the pressure range of 0–40 GPa are investigated. Further, we discuss the change in the optical properties of technetium phosphides at high pressures. At the end of our study, we focus on the research of the hardness of TcP4 at different pressures by employing a semiempirical method, and the effect of pressure on the hardness is studied. Results show that the hardness of TcP4 increases with the increasing pressure, and the influence mechanism of pressure effect on the hardness of TcP4 is also discussed.

  7. Metal phosphide catalysts and methods for making the same and uses thereof

    Energy Technology Data Exchange (ETDEWEB)

    Habas, Susan Ellen; Wang, Jun; Ruddy, Daniel A.; Baddour, Frederick Raymond Gabriel; Schaidle, Joshua

    2017-05-02

    The present disclosure relates to a method that includes heating a mixture that includes a metal phenylphosphine-containing precursor that includes at least one of Mo(PPh.sub.3).sub.2(CO).sub.4, Pd(PPh.sub.3).sub.4, Ru(PPh.sub.3).sub.3Cl.sub.2, Ru(PPh.sub.3).sub.2(CO).sub.2Cl.sub.2, Co(PPh.sub.3)(CO).sub.2(NO), and/or Rh(PPh.sub.3).sub.2(CO)Cl, a surfactant, and a solvent. The heating is to a target temperature to form a heated mixture containing a metal phosphide nanoparticle that includes at least one of MoP, Ru.sub.2P, Co.sub.2P, Rh.sub.2P, and/or Pd.sub.3P, and the metal phosphide nanoparticle is not hollow.

  8. Ingestion of gallium phosphide nanowires has no adverse effect on Drosophila tissue function.

    Science.gov (United States)

    Adolfsson, Karl; Schneider, Martina; Hammarin, Greger; Häcker, Udo; Prinz, Christelle N

    2013-07-19

    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.

  9. Ingestion of gallium phosphide nanowires has no adverse effect on Drosophila tissue function

    Science.gov (United States)

    Adolfsson, Karl; Schneider, Martina; Hammarin, Greger; Häcker, Udo; Prinz, Christelle N.

    2013-07-01

    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.

  10. Acetaminophen and zinc phosphide for lethal management of invasive lizards Ctenosaura similis

    Directory of Open Access Journals (Sweden)

    Michael L. AVERY, John D. EISEMANN, Kandy L. KEACHER,Peter J. SAVARIE

    2011-10-01

    Full Text Available Reducing populations of invasive lizards through trapping and shooting is feasible in many cases but effective integrated management relies on a variety of tools, including toxicants. In Florida, using wild-caught non-native black spiny-tailed iguanas Ctenosaura similis, we screened acetaminophen and zinc phosphide to determine their suitability for effective population management of this prolific invasive species. Of the animals that received acetaminophen, none died except at the highest test dose, 240 mg per lizard, which is not practical for field use. Zinc phosphide produced 100% mortality at dose levels as little as 25 mg per lizard, equivalent to about 0.5% in bait which is lower than currently used in commercial baits for commensal rodent control. We conclude that zinc phosphide has potential as a useful tool for reducing populations of invasive lizards such as the black spiny-tailed iguana provided target-selective delivery methods are developed [Current Zoology 57 (5: 625–629, 2011].

  11. A case report of zinc phosphide poisoning: complicated by acute renal failure and tubulo interstitial nephritis.

    Science.gov (United States)

    Yogendranathan, Nilukshana; Herath, H M M T B; Sivasundaram, Thenuka; Constantine, R; Kulatunga, Aruna

    2017-05-25

    Run Rat® is a rodenticide widely used against small mammals. It comprises of a minimum of 32% zinc phosphide which is highly toxic in acute exposures to humans. It may be consumed accidentally or intentionally. It enters the body via skin, respiratory and gastrointestinal tracts. Zinc phosphide is hydrolyzed by the gastric acid and is transformed into phosphine gas. Phosphine is a respiratory toxin that inhibits cytochrome C oxidase system resulting in renal failure and liver failure. A 35 year old Sri Lankan female presented following ingestion of 2.5 g of Run Rat®, which is a branded preparation of zinc phosphide, resulting in 61 mg/kg poison load. She developed severe acute kidney injury with acute tubular necrosis, subnephrotic ranged proteinuria and tubulointerstitial nephritis for which she underwent haemodialysis three times along with other measures of resuscitation. She also developed elevated liver enzymes with hyperblirubinaemia, hypoalbuminaemia, acute pancreatitis and mild myocarditis. She improved with supportive therapy over a period of 3 weeks. Run Rat® is a commonly used rodenticide and the toxic effects are mediated through conversion of phosphide to phosphine gas. The majority of the deaths had occurred in the first 12 to 24 h and the main causes identified are refractory hypotension and arrhythmias. The late deaths (beyond 24 h) had been commonly due to adult respiratory distress syndrome, liver and renal failure. The outcome is poorer with delayed presentation, development of coagulopathy, hyperglycaemia and multiorgan failure with elevated liver enzymes. In our patient, Zinc phosphide poisoning caused severe acute kidney injury, abnormal liver profile, pancreatitis and possible myocarditis. The patient improved with repeated haemodialysis. The renal biopsy revealed acute tubulointerstitial nephritis with acute tubular necrosis. In tropical countries, the rural population engaged in agriculture has easier access to the compound, as it

  12. Adsorption of hydrogen in Scandium/Titanium decorated nitrogen doped carbon nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Mananghaya, Michael, E-mail: mikemananghaya@gmail.com [De La Salle University, 2401 Taft Ave, 0922, Manila (Philippines); DLSU STC Laguna Boulevard, LTI Spine Road Barangays Biñan and Malamig, Biñan City, Laguna (Philippines); DOST-ASTHRDP, PCIEERD, Gen. Santos Ave., Bicutan, Taguig City 1631 (Philippines); Belo, Lawrence Phoa; Beltran, Arnel [De La Salle University, 2401 Taft Ave, 0922, Manila (Philippines); DLSU STC Laguna Boulevard, LTI Spine Road Barangays Biñan and Malamig, Biñan City, Laguna (Philippines)

    2016-09-01

    Nitrogen doped Carbon Nanotube with divacancy (4ND-CN{sub x}NT) that is decorated with Scandium and Titanium as potential hydrogen storage medium using the pseudo potential density functional method was investigated. Highly localized states near the Fermi level, which are derived from the nitrogen defects, contribute to strong Sc and Ti bindings, which prevent metal aggregation and improve the material stability. A detailed Comparison of the Hydrogen adsorption capability with promising system-weight efficiency of Sc over Ti was elucidated when functionalized with 4ND-CN{sub x}NT. Finally, the (Sc/4ND){sub 10}-CN{sub x}CNT composite material has a thermodynamically favorable adsorption and consecutive adsorption energy for ideal reversible adsorption and desorption of hydrogen at room temperature such that it can hold at least 5.8 wt% hydrogen molecules at the LDA and GGA level. - Highlights: • Carbon Nanotube with divacancy (4ND-CN{sub x}NT) decorated with Sc and Ti. • Nitrogen defects, contribute to strong Sc and Ti bindings. • H{sub 2} and (Sc/4ND){sub 10}-CN{sub x}CNT has a favorable adsorption. • 5.8 wt% adsorption at the LDA and GGA level.

  13. Urinary monitoring of exposure to yttrium, scandium, and europium in male Wistar rats.

    Science.gov (United States)

    Kitamura, Yasuhiro; Usuda, Kan; Shimizu, Hiroyasu; Fujimoto, Keiichi; Kono, Rei; Fujita, Aiko; Kono, Koichi

    2012-12-01

    On the assumption that rare earth elements (REEs) are nontoxic, they are being utilized as replacements of toxic heavy metals in novel technological applications. However, REEs are not entirely innocuous, and their impact on health is still uncertain. In the past decade, our laboratory has studied the urinary excretion of REEs in male Wistar rats given chlorides of europium, scandium, and yttrium solutions by one-shot intraperitoneal injection or oral dose. The present paper describes three experiments for the suitability and appropriateness of a method to use urine for biological monitoring of exposure to these REEs. The concentrations of REEs were determined in cumulative urine samples taken at 0-24 h by inductively coupled plasma atomic emission spectroscopy, showing that the urinary excretion of REEs is <2 %. Rare earth elements form colloidal conjugates in the bloodstream, which make high REEs accumulation in the reticuloendothelial system and glomeruli and low urinary excretion. The high sensitivity of inductively coupled plasma-argon emission spectrometry analytical methods, with detection limits of <2 μg/L, makes urine a comprehensive assessment tool that reflects REE exposure. The analytical method and animal experimental model described in this study will be of great importance and encourage further discussion for future studies.

  14. Scalable Indium Phosphide Thin-Film Nanophotonics Platform for Photovoltaic and Photoelectrochemical Devices.

    Science.gov (United States)

    Lin, Qingfeng; Sarkar, Debarghya; Lin, Yuanjing; Yeung, Matthew; Blankemeier, Louis; Hazra, Jubin; Wang, Wei; Niu, Shanyuan; Ravichandran, Jayakanth; Fan, Zhiyong; Kapadia, Rehan

    2017-05-23

    Recent developments in nanophotonics have provided a clear roadmap for improving the efficiency of photonic devices through control over absorption and emission of devices. These advances could prove transformative for a wide variety of devices, such as photovoltaics, photoelectrochemical devices, photodetectors, and light-emitting diodes. However, it is often challenging to physically create the nanophotonic designs required to engineer the optical properties of devices. Here, we present a platform based on crystalline indium phosphide that enables thin-film nanophotonic structures with physical morphologies that are impossible to achieve through conventional state-of-the-art material growth techniques. Here, nanostructured InP thin films have been demonstrated on non-epitaxial alumina inverted nanocone (i-cone) substrates via a low-cost and scalable thin-film vapor-liquid-solid growth technique. In this process, indium films are first evaporated onto the i-cone structures in the desired morphology, followed by a high-temperature step that causes a phase transformation of the indium into indium phosphide, preserving the original morphology of the deposited indium. Through this approach, a wide variety of nanostructured film morphologies are accessible using only control over evaporation process variables. Critically, the as-grown nanotextured InP thin films demonstrate excellent optoelectronic properties, suggesting this platform is promising for future high-performance nanophotonic devices.

  15. Three-dimensional interconnected nickel phosphide networks with hollow microstructures and desulfurization performance

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shuna, E-mail: zhangshujuan@tust.edu.cn [College of Textile Engineering, Zhejiang Industry Polytechnic College, Shaoxing 312000 (China); Zhang, Shujuan [College of Science, Tianjin University of Science and Technology, Tianjin 300457 (China); Song, Limin, E-mail: tjpu2012@sohu.com [College of Environment and Chemical Engineering and State Key Laboratory of Hollow-Fiber Membrane Materials and Membrane Processes, Tianjin Polytechnic University, Tianjin 300387 (China); Wu, Xiaoqing [Institute of Composite Materials and Ministry of Education Key Laboratory of Advanced Textile Composite Materials, Tianjin Polytechnic University, Tianjin 300387 (China); Fang, Sheng, E-mail: songlmnk@sohu.com [College of Environment and Chemical Engineering and State Key Laboratory of Hollow-Fiber Membrane Materials and Membrane Processes, Tianjin Polytechnic University, Tianjin 300387 (China)

    2014-05-01

    Graphical abstract: Three-dimensional interconnected nickel phosphide networks with hollow microstructures and desulfurization performance. - Highlights: • Three-dimensional Ni{sub 2}P has been prepared using foam nickel as a template. • The microstructures interconnected and formed sponge-like porous networks. • Three-dimensional Ni{sub 2}P shows superior hydrodesulfurization activity. - Abstract: Three-dimensional microstructured nickel phosphide (Ni{sub 2}P) was fabricated by the reaction between foam nickel (Ni) and phosphorus red. The as-prepared Ni{sub 2}P samples, as interconnected networks, maintained the original mesh structure of foamed nickel. The crystal structure and morphology of the as-synthesized Ni{sub 2}P were characterized by X-ray diffraction, scanning electron microscopy, automatic mercury porosimetry and X-ray photoelectron spectroscopy. The SEM study showed adjacent hollow branches were mutually interconnected to form sponge-like networks. The investigation on pore structure provided detailed information for the hollow microstructures. The growth mechanism for the three-dimensionally structured Ni{sub 2}P was postulated and discussed in detail. To investigate its catalytic properties, SiO{sub 2} supported three-dimensional Ni{sub 2}P was prepared successfully and evaluated for the hydrodesulfurization (HDS) of dibenzothiophene (DBT). DBT molecules were mostly hydrogenated and then desulfurized by Ni{sub 2}P/SiO{sub 2}.

  16. Structural analysis of a phosphide-based epitaxial structure with a buried oxidized AlAs sacrificial layer

    Science.gov (United States)

    Englhard, M.; Reuters, B.; Baur, J.; Klemp, C.; Zaumseil, P.; Schroeder, T.; Skibitzki, O.

    2017-06-01

    Phosphide-based thin-film light-emitting diodes (TF-LEDs) lattice-matched to GaAs are well established in optoelectronics in the wavelength range between 550 and 650 nm. In this work, we investigate the impact of oxidized AlAs to overlying phosphide-based pseudomorphically grown epitaxial structures. Oxidation of a buried AlAs sacrificial layer allows the separation of the grown TF-LED epitaxy from its substrates and enables an oxidation lift-off process. To evaluate the strain effect of progressing oxidation on the structure of the chip, we perform high-resolution x-ray diffraction analysis on as-grown, mesa-structured, semi-oxidized, and completely laterally oxidized chips. At each state, a pseudomorphic phosphide-based InAlP layer is found. The InAlP layer exhibits a tensile out-of-plane strain of approximately 0.20% and a compressive in-plane strain of approx. -0.19%. Additionally, scanning transmission electron microscopy, energy-dispersive x-ray spectroscopy, and μ-photoluminescence were used for investigation of the boundary zone of the oxidation front of AlAs, the interfaces between phosphide-based semiconductors (InAlP/InGaAlP) and oxidized amorphous AlAs and the light emission of InGaAlP multiple quantum wells.

  17. Selective recovery of vanadium and scandium by ion exchange with D201 and solvent extraction using P507 from hydrochloric acid leaching solution of red mud.

    Science.gov (United States)

    Zhu, Xiaobo; Li, Wang; Tang, Sen; Zeng, Majian; Bai, Pengyuan; Chen, Lunjian

    2017-05-01

    D201 resin and P507 extractant diluted with sulfonated kerosene were used to respectively separate vanadium and scandium, and impurity ions from hydrochloric acid leaching solution of red mud. More than 99% of vanadium was selectively adsorbed from the hydrochloric acid leaching solution under the conditions of pH value of 1.8, volume ratio of leaching solution to resin of 10, and flow rate of 3.33 mL/min. Maximum extraction and separation of scandium was observed from the acid leaching solution at an aqueous pH value of 0.2. More than 99% of scandium can be selectively extracted using 15% P507, 5% TBP at the aqueous solution/organic phase (A/O) ratio of 10:1 for 6 min. The loaded organic phase was washed with 0.3 mol/L sulfuric acid, wherein most impurities were removed. After the process of desorption or stripping, precipitation, and roasting, high-purity V2O5 and Sc2O3 were obtained. Finally, a conceptual flow sheet was established to separate and recover vanadium and scandium from red mud hydrochloric acid leaching solution. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Random-field Potts model for the polar domains of lead magnesium niobate and lead scandium tantalate

    Energy Technology Data Exchange (ETDEWEB)

    Qian, H.; Bursill, L.A

    1997-06-01

    A random filed Potts model is used to establish the spatial relationship between the nanoscale distribution of charges chemical defects and nanoscale polar domains for the perovskite-based relaxor materials lead magnesium niobate (PMN) and lead scandium tantalate (PST). The random fields are not set stochastically but are determined initially by the distribution of B-site cations (Mg, Nb) or (Sc, Ta) generated by Monte Carlo NNNI-model simulations for the chemical defects. An appropriate random field Potts model is derived and algorithms developed for a 2D lattice. It is shown that the local fields are strongly correlated with the chemical domain walls and that polar domains as a function of decreasing temperature is simulated for the two cases of PMN and PST. The dynamics of the polar clusters is also discussed. 33 refs., 9 figs.

  19. Molybdenum Disulfide as a Protection Layer and Catalyst for Gallium Indium Phosphide Solar Water Splitting Photocathodes

    Energy Technology Data Exchange (ETDEWEB)

    Britto, Reuben J.; Benck, Jesse D.; Young, James L.; Hahn, Christopher; Deutsch, Todd G.; Jaramillo, Thomas F.

    2016-06-02

    Gallium indium phosphide (GaInP2) is a semiconductor with promising optical and electronic properties for solar water splitting, but its surface stability is problematic as it undergoes significant chemical and electrochemical corrosion in aqueous electrolytes. Molybdenum disulfide (MoS2) nanomaterials are promising to both protect GaInP2 and to improve catalysis since MoS2 is resistant to corrosion and also possesses high activity for the hydrogen evolution reaction (HER). In this work, we demonstrate that GaInP2 photocathodes coated with thin MoS2 surface protecting layers exhibit excellent activity and stability for solar hydrogen production, with no loss in performance (photocurrent onset potential, fill factor, and light limited current density) after 60 hours of operation. This represents a five-hundred fold increase in stability compared to bare p-GaInP2 samples tested in identical conditions.

  20. Treatment of Aluminium Phosphide Poisoning with a Combination of Intravenous Glucagon, Digoxin and Antioxidant Agents

    Directory of Open Access Journals (Sweden)

    Zohreh Oghabian

    2016-08-01

    Full Text Available Aluminium phosphide (AlP is used to protect stored grains from rodents. It produces phosphine gas (PH3, a mitochondrial poison thought to cause toxicity by blocking the cytochrome c oxidase enzyme and inhibiting oxidative phosphorylation, which results in cell death. AlP poisoning has a high mortality rate among humans due to the rapid onset of cardiogenic shock and metabolic acidosis, despite aggressive treatment. We report a 21-yearold male who was referred to the Afzalipour Hospital, Kerman, Iran, in 2015 after having intentionally ingested a 3 g AlP tablet. He was successfully treated with crystalloid fluids, vasopressors, sodium bicarbonate, digoxin, glucagon and antioxidant agents and was discharged from the hospital six days after admission in good clinical condition. For the treatment of AlP poisoning, the combination of glucagon and digoxin with antioxidant agents should be considered. However, evaluation of further cases is necessary to optimise treatment protocols.

  1. Mesoporous Semimetallic Conductors: Structural and Electronic Properties of Cobalt Phosphide Systems.

    Science.gov (United States)

    Pramanik, Malay; Tominaka, Satoshi; Wang, Zhong-Li; Takei, Toshiaki; Yamauchi, Yusuke

    2017-10-16

    Mesoporous cobalt phosphide (meso-CoP) was prepared by the phosphorization of ordered mesoporous cobalt oxide (meso-Co3 O4 ). The electrical conductivity of meso-CoP is 37 times higher than that of nonporous CoP, and it displays semimetallic behavior with a negligibly small activation energy of 26 meV at temperatures below 296 K. Above this temperature, only materials with mesopores underwent a change in conductivity from semimetallic to semiconducting behavior. These properties were attributed to the coexistence of nanocrystalline Co2 P phases. The poor crystallinity of mesoporous materials has often been considered to be a problem but this example clearly shows its positive aspects. The concept introduced here should thus lead to new routes for the synthesis of materials with high electronic conductivity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Transition Metal Phosphide Nanoparticles Supported on SBA-15 as Highly Selective Hydrodeoxygenation Catalysts for the Production of Advanced Biofuels.

    Science.gov (United States)

    Yang, Yongxing; Ochoa-Hernández, Cristina; de la Peña O'Shea, Víctor A; Pizarro, Patricia; Coronado, Juan M; Serrano, David P

    2015-09-01

    A series of catalysts constituted by nanoparticles of transition metal (M = Fe, Co, Ni and Mo) phosphides (TMP) dispersed on SBA-15 were synthesized by reduction of the corresponding metal phosphate precursors previously impregnated on the mesostructured support. All the samples contained a metal-loading of 20 wt% and with an initial M/P mole ratio of 1, and they were characterized by X-ray diffraction (XRD), N2 sorption, H2-TPR and transmission electron microscopy (TEM). Metal phosphide nanocatalysts were tested in a high pressure continuous flow reactor for the hydrodeoxygenation (HDO) of a methyl ester blend containing methyl oleate (C17H33-COO-CH3) as main component (70%). This mixture constitutes a convenient surrogate of triglycerides present in vegetable oils, and following catalytic hydrotreating yields mainly n-alkanes. The results of the catalytic assays indicate that Ni2P/SBA-15 catalyst presents the highest ester conversion, whereas the transformation rate is about 20% lower for MoP/SBA-15. In contrast, catalysts based on Fe and Co phosphides show a rather limited activity. Hydrocarbon distribution in the liquid product suggests that both hydrodeoxygenation and decarboxylation/decarbonylation reactions occur simultaneously over the different catalysts, although MoP/SBA-15 possess a selectivity towards hydrodeoxygenation exceeding 90%. Accordingly, the catalyst based on MoP affords the highest yield of n-octadecane, which is the preferred product in terms of carbon atom economy. Subsequently, in order to conjugate the advantages of both Ni and Mo phosphides, a series of catalysts containing variable proportions of both metals were prepared. The obtained results reveal that the mixed phosphides catalysts present a catalytic behavior intermediate between those of the monometallic phosphides. Accordingly, only marginal enhancement of the yield of n-octadecane is obtained for the catalysts with a Mo/Ni ratio of 3. Nevertheless, owing to this high selectivity

  3. Materials Development for Boron Phosphide Based Neutron Detectors: Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Edgar, James Howard [Kansas State Univ., Manhattan, KS (United States)

    2014-09-09

    The project goal was to improve the quality of boron phosphide (BP) by optimizing its epitaxial growth on single crystal substrates and by producing bulk BP single crystals with low dislocation densities. BP is potentially a good semiconductor for high efficiency solid state neutron detectors by combining neutron capture and charge creation within the same volume. The project strategy was to use newly available single crystal substrates, silicon carbide and aluminum nitride, engineered to produce the best film properties. Substrate variables included the SiC polytype, crystallographic planes, misorientation of the substrate surface (tilt direction and magnitude) from the major crystallographic plane, and surface polarity (Si and C). The best films were (111)BP on silicon-face (0001) 4H-SiC misoriented 4° in the [1-100] direction, and BP on (100) and (111) 3C-SiC/Si; these substrates resulted in films that were free of in-plane twin defects, as determined by x-ray topography. The impact of the deposition temperature was also assessed: increasing the temperature from 1000 °C to 1200 °C produced films that were more ordered and more uniform, and the size of individual grains increased by more than a factor of twenty. The BP films were free of other compounds such as icosahedral boron phosphide (B12P2) over the entire temperature range, as established by Raman spectroscopy. The roughness of the BP films was reduced by increasing the phosphine to diborane ratio from 50 to 200. Bulk crystals were grown by reacting boron dissolved in nickel with phosphorus vapor to precipitate BP. Crystals with dimensions up to 2 mm were produced.

  4. Rodenticide Comparative Effect of Klerat® and Zinc Phosphide for Controlling Zoonotic Cutaneous Leishmaniasis in Central Iran

    Directory of Open Access Journals (Sweden)

    Arshad VEYSI

    2016-12-01

    Full Text Available Background: Zoonotic cutaneous leishmaniasis (ZCL is a neglected disease with public health importance that is common in many rural areas of Iran. In recent years, behavioral resistance and/or bait shyness against the common rodenticide among reservoir hosts of ZCL have been reported. The aim of this study was to evaluate the effectiveness of Klerat® and zinc phosphide against natural reservoir of ZCL.Methods: This survey was carried out in four villages located 45 to 95 km far from Esfahan City Esfahan province, central Iran from April to November 2011. The rodent burrows were counted destroyed and reopened holes baited around all villages. Effect of rodent control operation on the main vector density and incidence of ZCL were evaluated.Results: The reduction rate of rodent burrows after intervention calculated to be at 62.8% in Klerat® and 58.15% in zinc phosphide treated areas. Statistical analysis showed no difference between the densities of the vector in indoors and outdoors in intervention and control areas. The incidence of the disease between treated and control areas after intervention was statistically different (P< 0.05.Conclusion: Klerat® could be a suitable alternative for zinc phosphide in a specific condition such as behavior resistance or occurrence of bait shyness.

  5. Ensembles of indium phosphide nanowires: physical properties and functional devices integrated on non-single crystal platforms

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Nobuhiko P.; Lohn, Andrew; Onishi, Takehiro [University of California, Santa Cruz (United States). Baskin School of Engineering; NASA Ames Research Center, Nanostructured Energy Conversion Technology and Research (NECTAR), Advanced Studies Laboratories, Univ. of California Santa Cruz, Moffett Field, CA (United States); Mathai, Sagi; Li, Xuema; Straznicky, Joseph; Wang, Shih-Yuan; Williams, R.S. [Hewlett-Packard Laboratories, Information and Quantum Systems Laboratory, Palo Alto, CA (United States); Logeeswaran, V.J.; Islam, M.S. [University of California Davis, Electrical and Computer Engineering, Davis, CA (United States)

    2009-06-15

    A new route to grow an ensemble of indium phosphide single-crystal semiconductor nanowires is described. Unlike conventional epitaxial growth of single-crystal semiconductor films, the proposed route for growing semiconductor nanowires does not require a single-crystal semiconductor substrate. In the proposed route, instead of using single-crystal semiconductor substrates that are characterized by their long-range atomic ordering, a template layer that possesses short-range atomic ordering prepared on a non-single-crystal substrate is employed. On the template layer, epitaxial information associated with its short-range atomic ordering is available within an area that is comparable to that of a nanowire root. Thus the template layer locally provides epitaxial information required for the growth of semiconductor nanowires. In the particular demonstration described in this paper, hydrogenated silicon was used as a template layer for epitaxial growth of indium phosphide nanowires. The indium phosphide nanowires grown on the hydrogenerated silicon template layer were found to be single crystal and optically active. Simple photoconductors and pin-diodes were fabricated and tested with the view towards various optoelectronic device applications where group III-V compound semiconductors are functionally integrated onto non-single-crystal platforms. (orig.)

  6. A Plasma-Assisted Route to the Rapid Preparation of Transition-Metal Phosphides for Energy Conversion and Storage

    KAUST Repository

    Liang, Hanfeng

    2017-06-06

    Transition-metal phosphides (TMPs) are important materials that have been widely used in catalysis, supercapacitors, batteries, sensors, light-emitting diodes, and magnets. The physical and chemical structure of a metal phosphide varies with the method of preparation as the electronic, catalytic, and magnetic properties of the metal phosphides strongly depend on their synthesis routes. Commonly practiced processes such as solid-state synthesis and ball milling have proven to be reliable routes to prepare TMPs but they generally require high temperature and long reaction time. Here, a recently developed plasma-assisted conversion route for the preparation of TMPs is reviewed, along with their applications in energy conversion and storage, including water oxidation electrocatalysis, sodium-ion batteries, and supercapacitors. The plasma-assisted synthetic route should open up a new avenue to prepare TMPs with tailored structure and morphology for various applications. In fact, the process may be further extended to the synthesis of a wide range of transition-metal compounds such as borides and fluorides at low temperature and in a rapid manner.

  7. Highly efficient photocatalytic H2 evolution using TiO2 nanoparticles integrated with electrocatalytic metal phosphides as cocatalysts

    Science.gov (United States)

    Song, Rui; Zhou, Wu; Luo, Bing; Jing, Dengwei

    2017-09-01

    In this work, electrocatalysts like the metal phosphides Ni2P, NiCoP, and FeP, can serve as cocatalysts of TiO2 to form efficient composite photocatalysts for hydrogen generation from an aqueous methanol solution. On comparing Ni2P, NiCoP, and FeP and optimizing their proportions, the NiCoP(1 wt%)/TiO2 composite was found to exhibit the highest activity toward photocatalytic H2 production (1.54 μmol h-1 mg-1), which is about thirteen times that of the naked TiO2 nanoparticles. Mott-Schottky (MS) analysis indicated that the large upward shift or band bending of the Fermi energy level (EF) in metal phosphides was responsible for the enhanced activity of the composites. The steady-state photoluminescence (PL) spectra and photocurrent transient response further confirmed that the enhanced photoinduced charge transfer and band separation after TiO2 was integrated with the metal phosphides. Thus, these electrocatalysts were shown to be efficient cocatalysts that can replace noble metals as low-cost photocatalytic H2 production.

  8. Development of methods for the selective separation of scandium, zirconium and tin for radiopharmaceutical applications; Entwicklung von Methoden zur selektiven Trennung von Scandium, Zirkonium und Zinn fuer radiopharmazeutische Anwendungen

    Energy Technology Data Exchange (ETDEWEB)

    Dirks-Fandrei, Carina

    2014-07-01

    The subject of the present work is the development of fast and highly selective methods for the separation and purification of scandium, zirconium and tin radionuclides from potential target materials for use in nuclear medicine. A number of selected resins (TrisKem International) were first characterized with respect to their extraction behaviour towards a large number of cations. Characterization studies were performed in batch experiments by determination of weight distribution ratios D{sub w} and further the influence of interferences on the uptake of these elements was evaluated. Weight distribution ratios were determined in different acids and acid concentrations with main focus on scandium, tin or zirconium. The interference of macro amounts of Calcium and Ti on the Sc extraction was evaluated as well as the interference of macro amounts of Y on the Zr extraction. Best suited uptake conditions were found for Scandium on DGA were determined to be 2.5 M HNO{sub 3} for Ti-Targets and 0.1 M HNO{sub 3} for Calcium-Targets. Otherwise it is also possible to extract Sc with TRU Resin. High uptakes were obtained at 2.5 M HNO{sub 3} for simulated Ti- and Calcium-targets. Separation methods were developed using elution studies; employed conditions were chosen according to parameters evaluated in the batch-experiment. The developed methods allowed separating Sc very rapidly in high purity very rapidly from Ti- or Calcium-targets. For Zr a separation method based on UTEVA Resin has been developed. Following results of batch experiments simulated Y-target solution were loaded onto a UTEVA resin column from 6 M HNO{sub 3}; the elution of Zr could be performed in 0.01 M oxalic acid. Decontamination factors in the order of 10{sup 4}-10{sup 5} could be obtained applying the developed method; the method thus allowed separating Zr in a high purity. Initial testing of a method for the separation of Sn from Cd targets based on the use of TBP Resin showed that the TBP resin seems

  9. Inhibition of glucose-6-phosphate dehydrogenase protects hepatocytes from aluminum phosphide-induced toxicity.

    Science.gov (United States)

    Salimi, Ahmad; Paeezi, Maryam; Yousefsani, Bahareh Sadat; Shadnia, Shahin; Hassanian-Moghaddam, Hossein; Zamani, Nasim; Pourahmad, Jalal

    2017-11-01

    Aluminum phosphide (AlP) poisoning is a severe toxicity with 30-70% mortality rate. However, several case reports presented AlP-poisoned patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency and extensive hemolysis who survived the toxicity. This brought to our mind that maybe G6PD deficiency could protect the patients from severe fatal poisoning by this pesticide. In this research, we investigated the protective effect of 6-aminonicotinamide (6-AN)- as a well-established inhibitor of the NADP+- dependent enzyme 6-phosphogluconate dehydrogenase- on isolated rat hepatocytes in AlP poisoning. Hepatocytes were isolated by collagenase perfusion method and incubated into three different flasks: control, AlP, and 6-AN+ALP. Cellar parameters such as cell viability, reactive oxygen species (ROS) formation, mitochondria membrane potential collapse (MMP), lysosomal integrity, content of reduced (GSH) and oxidized glutathione (GSSG) and lipid peroxidation were assayed at intervals. All analyzed cellular parameters significantly decreased in the third group (6-AN+AlP) compared to the second group (AlP), showing the fact that G6PD deficiency induced by 6-AN had a significant protective effect on the hepatocytes. It was concluded that G6PD deficiency significantly reduced the hepatotoxicity of AlP. Future drugs with the power to induce such deficiency may be promising in treatment of AlP poisoning. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Photoluminescence blue shift of indium phosphide nanowire networks with aluminum oxide coating

    Energy Technology Data Exchange (ETDEWEB)

    Fryauf, David M.; Zhang, Junce; Norris, Kate J.; Diaz Leon, Juan J.; Oye, Michael M.; Kobayashi, Nobuhiko P. [Nanostructured Energy Conversion Technology and Research (NECTAR), Advanced Studies Laboratories, University of California, Santa Cruz, CA (United States); Baskin School of Engineering, University of California Santa Cruz, Santa Cruz, CA (United States); NASA Ames Research Center, Moffett Field, CA (United States); Wei, Min [Baskin School of Engineering, University of California Santa Cruz, Santa Cruz, CA (United States); School of Micro-Electronics and Solid-Electronics, University of Electronic Science and Technology of China, Chengdu (China)

    2014-07-15

    This paper describes our finding that optical properties of semiconductor nanowires were modified by depositing a thin layer of metal oxide. Indium phosphide nanowires were grown by metal organic chemical vapor deposition on silicon substrates with gold catalyst resulting in three-dimensional nanowire networks, and optical properties were obtained from the collective nanowire networks. The networks were coated with an aluminum oxide thin film deposited by plasma-enhanced atomic layer deposition. We studied the dependence of the peak wavelength of photoluminescence spectra on the thickness of the oxide coatings. A continuous blue shift in photoluminescence spectra was observed when the thickness of the oxide coating was increased. The observed blue shift is attributed to the Burstein-Moss effect due to increased carrier concentration in the nanowire cores caused by repulsion from intrinsic negative fixed charges located at the inner oxide surface. Samples were further characterized by scanning electron microscopy, Raman spectroscopy, transmission electron microscopy, and selective area diffractometry to better understand the physical mechanisms for the blue shift. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Electrostatically driven resonance energy transfer in "cationic" biocompatible indium phosphide quantum dots.

    Science.gov (United States)

    Devatha, Gayathri; Roy, Soumendu; Rao, Anish; Mallick, Abhik; Basu, Sudipta; Pillai, Pramod P

    2017-05-01

    Indium Phosphide Quantum Dots (InP QDs) have emerged as an alternative to toxic metal ion based QDs in nanobiotechnology. The ability to generate cationic surface charge, without compromising stability and biocompatibility, is essential in realizing the full potential of InP QDs in biological applications. We have addressed this challenge by developing a place exchange protocol for the preparation of cationic InP/ZnS QDs. The quaternary ammonium group provides the much required permanent positive charge and stability to InP/ZnS QDs in biofluids. The two important properties of QDs, namely bioimaging and light induced resonance energy transfer, are successfully demonstrated in cationic InP/ZnS QDs. The low cytotoxicity and stable photoluminescence of cationic InP/ZnS QDs inside cells make them ideal candidates as optical probes for cellular imaging. An efficient resonance energy transfer (E ∼ 60%) is observed, under physiological conditions, between the cationic InP/ZnS QD donor and anionic dye acceptor. A large bimolecular quenching constant along with a linear Stern-Volmer plot confirms the formation of a strong ground state complex between the cationic InP/ZnS QDs and the anionic dye. Control experiments prove the role of electrostatic attraction in driving the light induced interactions, which can rightfully form the basis for future nano-bio studies between cationic InP/ZnS QDs and anionic biomolecules.

  12. Metal Phosphides as Co-Catalysts for Photocatalytic and Photoelectrocatalytic Water Splitting.

    Science.gov (United States)

    Cao, Shuang; Wang, Chuan-Jun; Fu, Wen-Fu; Chen, Yong

    2017-11-23

    Solar-to-hydrogen conversion based on photocatalytic and photoelectrocatalytic water splitting is considered as a promising technology for sustainable hydrogen production. Developing earth-abundant H 2 -production materials with robust activity and stability has become the mainstream in this field. Due to the unique properties and characteristics, transition metal phosphides (TMPs) have been proven to be high performance co-catalysts to replace some of the classic precious metal materials in photocatalytic water splitting. In this Minireview, we summarize the recent significant progress of TMPs as cocatalysts for water splitting reaction with high activity and stability. Firstly, the characteristic of TMPs is briefly introduced. Then, we mainly discuss the recent research efforts toward their application as photocatalytic co-catalysts in photocatalytic H 2 -production, O 2 -evolution and photoelectrochemical water splitting. Finally, the catalytic mechanism, current existing challenges and future working directions for improving the performance of TMPs are proposed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Heterogeneous Bimetallic Phosphide/Sulfide Nanocomposite for Efficient Solar-Energy-Driven Overall Water Splitting.

    Science.gov (United States)

    Xin, Yanmei; Kan, Xiang; Gan, Li-Yong; Zhang, Zhonghai

    2017-10-24

    Solar-driven overall water splitting is highly desirable for hydrogen generation with sustainable energy sources, which need efficient, earth-abundant, robust, and bifunctional electrocatalysts for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Herein, we propose a heterogeneous bimetallic phosphide/sulfide nanocomposite electrocatalyst of NiFeSP on nickel foam (NiFeSP/NF), which shows superior electrocatalytic activity of low overpotentials of 91 mV at -10 mA cm -2 for HER and of 240 mV at 50 mA cm -2 for OER in 1 M KOH solution. In addition, the NiFeSP/NF presents excellent overall water splitting performance with a cell voltage as low as 1.58 V at a current density of 10 mA cm -2 . Combining with a photovoltaic device of a Si solar cell or integrating into photoelectrochemical (PEC) systems, the bifunctional NiFeSP/NF electrocatalyst implements unassisted solar-driven water splitting with a solar-to-hydrogen conversion efficiency of ∼9.2% and significantly enhanced PEC performance, respectively.

  14. Hydrodesulfurization Properties of Rhodium Phosphide: Comparison with Rhodium Metal and Sulfide Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, John R.; Bowker, Richard H.; Gaudette, Amy F.; Smith, Mica C.; Moak, Cameron E.; Nam, Charles Y.; Pratum, Thomas K.; Bussell, Mark E.

    2010-12-15

    Silica-supported rhodium phosphide (Rh2P/SiO2) catalysts were prepared and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), 31P solid-state NMR spectroscopy, X-ray photoelectron spectroscopy (XPS), and chemisorption measurements. XRD and TEM analysis of a 5 wt.% Rh2P/SiO2 catalyst confirmed the presence of well-dispersed Rh2P crystallites on the silica support having an average crystallite size of 10 nm. NMR spectroscopy showed unsupported and silica-supported Rh2P to be metallic and XPS spectroscopy yielded a surface composition of Rh1.94P1.00 that is similar to that expected from the bulk stoichiometry. The 5 wt.% Rh2P/SiO2 catalyst exhibited a higher dibenzothiophene (DBT) hydrodesulfurization (HDS) activity than did Rh/SiO2 and sulfided Rh/SiO2 catalysts having a similar Rh loading and was also more active than a commercial NiAMo/Al2O3 catalyst. The Rh2P/SiO2 catalyst showed excellent stability over a 100 h DBT HDS activity measurement and was more S tolerant than the Rh/SiO2 catalyst. The Rh2P/SiO2 catalyst strongly favored the hydrogenation pathway for DBT HDS, while the Rh/SiO2 and sulfided Rh/SiO2 catalysts favored the direct desulfurization pathway.

  15. Antioxidant Therapy in Patients with Severe Aluminum Phosphide Poisoning: A Pilot Study.

    Science.gov (United States)

    Bhalla, Ashish; Jyothinath, P; Singh, Surjit

    2017-12-01

    N-acetyl cysteine (NAC) is a powerful antioxidant and has been used extensively in the treatment of paracetamol overdose with great success. Aluminum phosphide (ALP) ingestion results in significant oxidative stress. In this study, we evaluated the effects of NAC on mortality in patients with severe ALP poisoning. This prospective intervention study was carried out in the emergency medical unit attached to the Nehru Hospital at PGIMER, Chandigarh, over a period of 1 year. All the patients presenting with severe ALP poisoning were randomized into two group. The treatment group received NAC in the dose of 150 mg/kg intravenous over 1 h, followed by 50 mg/kg over 4 h, followed by 100 mg/kg 16 h in 5% dextrose. The placebo group received 5% dextrose. The primary end point was mortality. A total of 50 patients were recruited. The baseline parameters were comparable in both groups. The survivors in the treatment group received 19 g of NAC, but the nonsurvivors received only 12.15 g of NAC. The overall mortality in the study group was 88% with 87.5% mortality in the treatment group and 88.5% in the placebo group. Antioxidant therapy in the form of NAC in severe ALP poisoning did not confer any survival benefit.

  16. Diagnosis of aluminum phosphide poisoning using a new analytical approach: forensic application to a lethal intoxication.

    Science.gov (United States)

    Yan, Hui; Xiang, Ping; Zhang, Sujing; Shen, Baohua; Shen, Min

    2017-07-01

    Aluminum phosphide (AlP) is an effective and cheap pesticide that is commonly used worldwide, but it is also a common cause of human poisoning and carries a high mortality rate. AlP reacts with moisture in air, water, and hydrochloric acid in the stomach to produce phosphine (PH3) gas. Two routes of exposure are ingestion of AlP and inhalation of phosphine generated by the action of moisture on AlP. Absorbed phosphine is rapidly metabolized into phosphite and hypophosphite. A method is described for the analysis of the phosphine metabolites in various biological matrices. The method involves reacting the sample with zinc and aqueous H2SO4 in a volatile organic analysis vial. The metabolites were transformed into phosphine gas and then analyzed by headspace gas chromatography coupled with mass spectrometry (HS-GC-MS). This method is capable of detecting quantities of PH3 as low as 0.2 μg/mL in a sample. After validation, the method was applied to animal experiments and a real case of human AlP intoxication. This approach has the advantage of detecting metabolites of PH3, in case the PH3 was converted, and can be considered a useful additional tool for the diagnosis of AlP poisoning in forensic science.

  17. Triamidoamine-uranium(IV)-stabilized terminal parent phosphide and phosphinidene complexes

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, Benedict M.; McMaster, Jonathan; Lewis, William; Blake, Alexander J.; Liddle, Stephen T. [School of Chemistry, University of Nottingham (United Kingdom); Balazs, Gabor; Scheer, Manfred [Institut of Inorganic Chemistry, University of Regensburg (Germany); Tuna, Floriana; McInnes, Eric J.L. [School of Chemistry and Photon Science Institute, University of Manchester (United Kingdom)

    2014-04-22

    Reaction of [U(Tren{sup TIPS})(THF)][BPh{sub 4}] (1; Tren{sup TIPS}=N{CH_2CH_2NSi(iPr)_3}{sub 3}) with NaPH{sub 2} afforded the novel f-block terminal parent phosphide complex [U(Tren {sup TIPS})(PH{sub 2})] (2; U-P=2.883(2) Aa). Treatment of 2 with one equivalent of KCH{sub 2}C{sub 6}H{sub 5} and two equivalents of benzo-15-crown-5 ether (B15C5) afforded the unprecedented metal-stabilized terminal parent phosphinidene complex [U(Tren{sup TIPS})(PH)][K(B15C5){sub 2}] (4; U=P=2.613(2) Aa). DFT calculations reveal a polarized-covalent U=P bond with a Mayer bond order of 1.92. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Physical properties of new cerium palladium phosphide with C6Cr23-type structure

    Directory of Open Access Journals (Sweden)

    T. Abe

    2014-01-01

    Full Text Available We have found that a cerium palladium phosphide crystallizes into a C6Cr23-type structure with atomic disorder. Prepared polycrystalline samples show a homogeneity range in the ternary Ce–Pd–P phase diagram. The physical properties of the highest-quality sample of Ce2.4Pd20.7P5.9 were investigated by measuring the magnetization, electrical resistivity and specific heat. No pronounced phase transition was observed down to 0.5 K. The Kondo screening of localized 4f electrons in metallic Ce2.4Pd20.7P5.9 appears to be weaker than that in the isostructural compounds of Ce3Pd20Si6 and Ce3Pd20Ge6. By a comparative study of Ce2.4Pd20.7P5.9 and Ce3Pd20X6 (X = Si, Ge, the competition between the Kondo temperature and ordering temperatures including the quadrupolar ordering temperature is briefly discussed.

  19. The impact of an erbium, chromium:yttrium-scandium-gallium-garnet laser with radial-firing tips on endodontic treatment.

    Science.gov (United States)

    Schoop, U; Barylyak, A; Goharkhay, K; Beer, F; Wernisch, J; Georgopoulos, A; Sperr, W; Moritz, A

    2009-01-01

    Radial-firing tips should allow a more homogeneous laser irradiation of root canal walls. The aim of the study was to assess the effects of erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser irradiation in conjunction with those newly designed tips. The investigation comprised bacteriology, morphological evaluations and temperature measurements. Root canals were inoculated with two test strains and laser irradiated with power settings of 0.6 W and 0.9 W and a repetition rate of 20 Hz. Subsequently, the samples were subjected to microbiological evaluation. The morphological changes of the canal walls were assessed by scanning electron microscopy. To reveal possible thermal side effects, we carried out temperature measurements. The bacteriological evaluation revealed a decisive disinfectant effect. Scanning electron microscopy showed the homogeneous removal of smear layer from the root canal walls. The temperature rise at the root surface during the irradiation was moderate, yielding 1.3 degrees C for the 0.6 W setting and 1.6 degrees C for the 0.9 W setting. The investigations indicated that the Er,Cr:YSGG laser, in conjunction with radial-firing tips, is a suitable tool for the elimination of bacteria in root canals and for the removal of smear layer.

  20. Effect of scandium addition on the microstructure, mechanical and wear properties of the spray formed hypereutectic aluminum–silicon alloys

    Energy Technology Data Exchange (ETDEWEB)

    Raghukiran, Nadimpalli; Kumar, Ravi, E-mail: nvrk@iitm.ac.in

    2015-08-12

    Hypereutectic Al–x%Si–0.8Sc alloys (x=13, 16, 19 and 22 wt%) were produced by spray forming. The microstructures of all the alloys exhibited very fine silicon phase with average size of about 5–10 µm irrespective of the silicon content of the alloy. Transmission electron microscopy revealed the presence of a nano-scale scandium rich phase, identified as AlSi{sub 2}Sc{sub 2} (V-phase) uniformly distributed in the alloy. The presence of V-phase resulted in higher matrix hardness (1.34 GPa) in contrast to 1.04 GPa observed in the case of binary Al–Si alloys by nanoindentation. Isothermal heat treatment at 375 °C revealed insignificant coarsening of silicon phase in both binary and ternary alloys. The Al–x%Si–0.8Sc alloys exhibited higher flow stress and tensile strength in contrast to their binary alloy counterparts which was attributed to the bi-modal size distribution of the strengthening phases in the form of nano-scale V-phase and sub-micron to 10 µm size silicon particles. The pin-on-disk wear tests exhibited appreciable improvement in the wear performance of the relatively low-silicon content ternary alloys over their binary counterparts while the high-silicon content binary and ternary alloys exhibited no much difference in the wear performance.

  1. Scandium and Titanium Containing Single-Walled Carbon Nanotubes for Hydrogen Storage: a Thermodynamic and First Principle Calculation.

    Science.gov (United States)

    Mananghaya, Michael; Yu, Dennis; Santos, Gil Nonato; Rodulfo, Emmanuel

    2016-06-15

    The generalized gradient approximation (GGA) to density functional theory (DFT) calculations indicate that the highly localized states derived from the defects of nitrogen doped carbon nanotube with divacancy (4ND-CNxNT) contribute to strong Sc and Ti bindings, which prevent metal aggregation. Comparison of the H2 adsorption capability of Sc over Ti-decorated 4ND-CNxNT shows that Ti cannot be used for reversible H2 storage due to its inherent high adsorption energy. The Sc/4ND-CNxNT possesses favorable adsorption and consecutive adsorption energy at the local-density approximation (LDA) and GGA level. Molecular dynamics (MD) study confirmed that the interaction between molecular hydrogen and 4ND-CNxNT decorated with scandium is indeed favorable. Simulations indicate that the total amount of adsorption is directly related to the operating temperature and pressure. The number of absorbed hydrogen molecules almost logarithmically increases as the pressure increases at a given temperature. The total excess adsorption of hydrogen on the (Sc/4ND)10-CNxNT arrays at 300 K is within the range set by the department of energy (DOE) with a value of at least 5.85 wt%.

  2. Effect of dislocations on the open-circuit voltage, short-circuit current and efficiency of heteroepitaxial indium phosphide solar cells

    Science.gov (United States)

    Jain, Raj K.; Flood, Dennis J.

    1990-01-01

    Excellent radiation resistance of indium phosphide solar cells makes them a promising candidate for space power applications, but the present high cost of starting substrates may inhibit their large scale use. Thin film indium phosphide cells grown on Si or GaAs substrates have exhibited low efficiencies, because of the generation and propagation of large number of dislocations. Dislocation densities were calculated and its influence on the open circuit voltage, short circuit current, and efficiency of heteroepitaxial indium phosphide cells was studied using the PC-1D. Dislocations act as predominant recombination centers and are required to be controlled by proper transition layers and improved growth techniques. It is shown that heteroepitaxial grown cells could achieve efficiencies in excess of 18 percent AMO by controlling the number of dislocations. The effect of emitter thickness and surface recombination velocity on the cell performance parameters vs. dislocation density is also studied.

  3. Comparison of the prognosis of the new and old therapeutic protocols in poisoning by phosphide compounds

    Directory of Open Access Journals (Sweden)

    Jafar Navabi

    2017-05-01

    Full Text Available Introduction: Rice tablets (aluminum phosphide are used to fight insects and pests in the grain storage spaces. This tablet produces phosphine gas which is a toxic substance for mitochondria. New measures have merely been recommended to save the lives of poisoned patients at referral clinical toxicology centers. The purpose of this study is to compare the prognosis of the new and old protocols in rice tablet poisoning. Methods: This clinical trial recruited 126 eligible patients poisoned with rice tablets presenting to the Imam Khomeini Hospital in Kermanshah in 2013, who were assigned into two groups of the new (magnesium sulfate and old protocols. Data were analyzed using statistical tests in SPSS software version 21. Results: The age of the patients was between 12 and 76 years, with a mean of 30.78 years and a standard deviation of 12.88 years. Among the patients, 77 (58.3% were male and 55 (41.7% were female. 43.9%/59.1%, 16.7%/31.8%, 9.1%/25.8%, and 40.9%/42.4% subjects suffered from cardiac, renal, hepatic and pulmonary complications, in new and old treatment groups respectively. Renal (P=0.046 and hepatic (P=0.12% complications were significantly lower in patients under the new treatment. Furthermore, the mortality rate in the new protocol was significantly lower (P=0.036. Conclusion: In this study, the new protocol was better able than the old one to reduce morbidity and mortality rates. Therefore, the use of this new treatment protocol can be beneficial in the treatment of patients poisoned with rice tablets.

  4. Crystalline Copper Phosphide Nanosheets as an Efficient Janus Catalyst for Overall Water Splitting.

    Science.gov (United States)

    Han, Ali; Zhang, Hanyu; Yuan, Ruihan; Ji, Hengxing; Du, Pingwu

    2017-01-25

    Hydrogen is essential to many industrial processes and could play an important role as an ideal clean energy carrier for future energy supply. Herein, we report for the first time the growth of crystalline Cu 3 P phosphide nanosheets on conductive nickel foam (Cu 3 P@NF) for electrocatalytic and visible light-driven overall water splitting. Our results show that the Cu 3 P@NF electrode can be used as an efficient Janus catalyst for both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). For OER catalysis, a current density of 10 mA/cm 2 requires an overpotential of only ∼320 mV and the slope of the Tafel plot is as low as 54 mV/dec in 1.0 M KOH. For HER catalysis, the overpotential is only ∼105 mV to achieve a catalytic current density of 10 mA cm -2 . Moreover, overall water splitting can be achieved in a water electrolyzer based on the Cu 3 P@NF electrode, which showed a catalytic current density of 10 mA/cm 2 under an applied voltage of ∼1.67 V. The same current density can also be obtained using a silicon solar cell under ∼1.70 V for both the HER and the OER. This new Janus Cu 3 P@NF electrode is made of inexpensive and nonprecious metal-based materials, which opens new possibilities based on copper to exploit overall water splitting for hydrogen production. To the best of our knowledge, such high performance of a copper-based water oxidation and overall water splitting catalyst has not been reported to date.

  5. Alteration in Liver Enzymes in Aluminum Phosphide Poisoning, A Retrospective Study

    Directory of Open Access Journals (Sweden)

    Morteza Rahbar Taramsari

    2016-07-01

    Full Text Available Background: Aluminum phosphide (ALP or rice tablet is a common agent used as pesticides. It is cheap, widely available and highly toxic and responsible for many cases of poisoning in the agricultural communities. There is limited evidence about change of liver enzymes in patients with ALP poisoning in this region. Therefore, we decided to evaluate alteration of liver enzymes in ALP poisoning in Rasht. Methods: In this retrospective cross-sectional study, all documents of patients with ALP poisoning admitted to Razi hospital of Rasht in 2008-2009 were assessed. Inclusion criteria were diagnostic clinical manifestation such as hypotension or metabolic acidosis, history of exposure to ALP during the past 24 hours and progressive signs and symptoms despite treatment (administration of sodium bicarbonate and vasopressor. Patients with past history of hepatic disease were excluded. Collected data were analyzed with SPSS software. Results: Of 104 patients with ALP poisoning, 66 patients (63.5% were men. The mean age was 33.8±14.69 years, and the mean time of hospitalization was 14.94±18.28 hours. Ninety-five patients (91.3% needed ventilation and 93 patients (89.4% died. Statistical analysis demonstrated that elevated liver enzymes were not significantly related with gender, age, time of admission, time of hospitalization, the need for ventilation and mortality. Conclusion: It seems that liver enzymes changes is not seen widely in ALP poisoning and had lower importance than other complications. Because of limited studies in liver enzyme alterations in these patients, it is suggested that more studies with largee sample size is performed to investigate the ALP liver side effects.

  6. Hydroxyethyl Starch Could Save a Patient With Acute Aluminum Phosphide Poisoning

    Directory of Open Access Journals (Sweden)

    Sayed Mahdi Marashi

    2016-07-01

    Full Text Available A 40-year-old male patient with suicidal ingestion of one tablet of aluminium phosphide was referred to the department of toxicology emergency of Baharloo Hospital, Tehran, Iran. The garlic odor was smelled from the patient and abdominal pain and continuous vomiting as well as agitation and heartburn were the first signs and symptoms. Systolic and diastolic blood pressures at the arrival time were 95 and 67 mmHg, respectively. Gastric lavage with potassium permanganate (1:10,000, and 2 vials of sodium bicarbonate through a nasogastric tube was started for the patient and the management was continued with free intravenous infusion of 1 liter of NaCl 0.9% serum plus NaHCO3, hydrocortisone acetate (200 mg, calcium gluconate (1 g and magnesium sulfate (1 g. Regarding the large intravenous fluid therapy and vasoconstrictor administering (norepinephrine started by 5 µg/min and continued till 15 µg/min, there were no signs of response and the systolic blood pressure was 49 mmHg. At this time, hydroxyethyl starch (HES (6% hetastarch 600/0.75 in 0.9% sodium chloride with a dose of 600 cc in 6 hours was started for the patient. At the end of therapy with HES, the patient was stable with systolic and diastolic blood pressure of 110 and 77 mmHg, respectively. He was discharged on the 6th day after the psychological consultation, with normal clinical and paraclinical examinations. This is the first report of using HES in the management of AlP poisoning and its benefit to survive the patient.

  7. Electrocatalytic and photocatalytic hydrogen production from acidic and neutral-pH aqueous solutions using iron phosphide nanoparticles.

    Science.gov (United States)

    Callejas, Juan F; McEnaney, Joshua M; Read, Carlos G; Crompton, J Chance; Biacchi, Adam J; Popczun, Eric J; Gordon, Thomas R; Lewis, Nathan S; Schaak, Raymond E

    2014-11-25

    Nanostructured transition-metal phosphides have recently emerged as Earth-abundant alternatives to platinum for catalyzing the hydrogen-evolution reaction (HER), which is central to several clean energy technologies because it produces molecular hydrogen through the electrochemical reduction of water. Iron-based catalysts are very attractive targets because iron is the most abundant and least expensive transition metal. We report herein that iron phosphide (FeP), synthesized as nanoparticles having a uniform, hollow morphology, exhibits among the highest HER activities reported to date in both acidic and neutral-pH aqueous solutions. As an electrocatalyst operating at a current density of -10 mA cm(-2), FeP nanoparticles deposited at a mass loading of ∼1 mg cm(-2) on Ti substrates exhibited overpotentials of -50 mV in 0.50 M H2SO4 and -102 mV in 1.0 M phosphate buffered saline. The FeP nanoparticles supported sustained hydrogen production with essentially quantitative faradaic yields for extended time periods under galvanostatic control. Under UV illumination in both acidic and neutral-pH solutions, FeP nanoparticles deposited on TiO2 produced H2 at rates and amounts that begin to approach those of Pt/TiO2. FeP therefore is a highly Earth-abundant material for efficiently facilitating the HER both electrocatalytically and photocatalytically.

  8. Surface-oxidized cobalt phosphide used as high efficient electrocatalyst in activated carbon air-cathode microbial fuel cell

    Science.gov (United States)

    Yang, Tingting; Wang, Zhong; Li, Kexun; Liu, Yi; Liu, Di; Wang, Junjie

    2017-09-01

    Herein, we report a simplistic method to fabricate the surface-oxidized cobalt phosphide (CoP) nanocrystals (NCs), which is used as electrocatalyst for oxygen reduction reaction (ORR) in microbial fuel cell (MFC) for the first time. The corallite-like CoP NCs are successfully prepared by a hydrothermal reaction following a phosphating treatment in N2 atmosphere. When used as an ORR catalyst, cobalt phosphide shows comparable onset potential, inferior resistance, as well as a small Tafel slope with long-term stability in neutral media. The maximum power density of MFC embellished with 10% CoP reached 1914.4 ± 59.7 mW m-2, which is 108.5% higher than the control. The four-electron pathway, observed by the RDE, plays a crucial role in electrochemical catalytic activity. In addition, material characterizations indicate that the surface oxide layer (CoOx) around the metallic CoP core is important and beneficial for ORR. Accordingly, it can be expected that the as-synthesized CoP will be a promising candidate of the non-precious metal ORR electrocatalysts for electrochemical energy applications.

  9. MOF-Derived Ultrathin Cobalt Phosphide Nanosheets as Efficient Bifunctional Hydrogen Evolution Reaction and Oxygen Evolution Reaction Electrocatalysts

    Directory of Open Access Journals (Sweden)

    Hong Li

    2018-02-01

    Full Text Available The development of a highly efficient and stable bifunctional electrocatalyst for water splitting is still a challenging issue in obtaining clean and sustainable chemical fuels. Herein, a novel bifunctional catalyst consisting of 2D transition-metal phosphide nanosheets with abundant reactive sites templated by Co-centered metal−organic framework nanosheets, denoted as CoP-NS/C, has been developed through a facile one-step low-temperature phosphidation process. The as-prepared CoP-NS/C has large specific surface area and ultrathin nanosheets morphology providing rich catalytic active sites. It shows excellent electrocatalytic performances for hydrogen evolution reaction (HER and oxygen evolution reaction (OER in acidic and alkaline media, with the Tafel slopes of 59 and 64 mV/dec and a current density of 10 mA/cm2 at the overpotentials of 140 and 292 mV, respectively, which are remarkably superior to those of CoP/C, CoP particles, and comparable to those of commercial noble-metal catalysts. In addition, the CoP-NS/C also shows good durability after a long-term test.

  10. Strong coupling superconductivity at 8.4 K in an antiperovskite phosphide SrPt3P.

    Science.gov (United States)

    Takayama, T; Kuwano, K; Hirai, D; Katsura, Y; Yamamoto, A; Takagi, H

    2012-06-08

    We report the discovery of a family of ternary platinum phosphides APt3P (A = Ca, Sr, and La), which crystallize in an antiperovskite-based structure closely related to that of the heavy fermion superconductor CePt3Si. All three phosphides showed superconductivity at low temperatures and the highest critical temperature T(c) = 8.4  K was observed for SrPt3P. The analysis of specific heat C(T) for SrPt3P shows clear evidence for very strong coupling s-wave superconductivity with a large ratio between superconducting gap Δ0 and T(c), 2Δ0/k(B)T(c) ∼ 5, and the presence of low-energy phonons. The presence of multiple Fermi surface pockets was inferred from the nonlinear magnetic field dependence of Hall resistivity, which we argue might play a role in realizing the strong coupling of charge carriers with the low-lying phonons.

  11. Study of laboratory profile in patients with aluminium phosphide poisoning in the southwest of Iran from 2010 to 2015

    Directory of Open Access Journals (Sweden)

    Farkhonde Jamshidi

    2017-03-01

    Full Text Available Introduction : Aluminium phosphide or rice tablet is one of the most common pesticides around the world. The substance releases phosphine gas in the presence of water, steam or stomach acid which can lead to poisoning. Phosphine poisoning is more about suicide the number of which is increasing day by day. Two-thirds of patients lose their lives. The aim of this study was to evaluate the data on the clinical epidemiology and laboratory changes in patients poisoned with rice tablets. Material and methods : A total of 23 patients poisoned by aluminium phosphide who referred to Ahvaz Razi hospital within the period of 2010–2015 were studied. The data were analyzed using descriptive statistics and statistical tests. Results : The mean age of the patients was 27.2 ±7.3 years and 60.9% of the patients were male. 8.7% of the patients had hyponatremia and 21.7% of the patients had hypokalemia. In the majority of cases the amount of sodium and potassium was normal. 91% of patients had acidosis and serum bicarbonate was reduced in the majority of cases. The average interval between poisoning and admission was 1.48 ±0.76 hours. Conclusions : The pattern to change the electrolytes and other laboratory factors could be a good marker of the severity of the poisoning and the clinical conditions of the patient, which requires more specific research to prove the process.

  12. Colloidal Cobalt Phosphide Nanocrystals as Trifunctional Electrocatalysts for Overall Water Splitting Powered by a Zinc-Air Battery.

    Science.gov (United States)

    Li, Hui; Li, Qi; Wen, Peng; Williams, Trey B; Adhikari, Shiba; Dun, Chaochao; Lu, Chang; Itanze, Dominique; Jiang, Lin; Carroll, David L; Donati, George L; Lundin, Pamela M; Qiu, Yejun; Geyer, Scott M

    2018-03-01

    Highly efficient and stable electrocatalysts, particularly those that are capable of multifunctionality in the same electrolyte, are in high demand for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). In this work, highly monodisperse CoP and Co 2 P nanocrystals (NCs) are synthesized using a robust solution-phase method. The highly exposed (211) crystal plane and abundant surface phosphide atoms make the CoP NCs efficient catalysts toward ORR and HER, while metal-rich Co 2 P NCs show higher OER performance owing to easier formation of plentiful Co 2 P@COOH heterojunctions. Density functional theory calculation results indicate that the desorption of OH* from cobalt sites is the rate-limiting step for both CoP and Co 2 P in ORR and that the high content of phosphide can lower the reaction barrier. A water electrolyzer constructed with a CoP NC cathode and a Co 2 P NC anode can achieve a current density of 10 mA cm -2 at 1.56 V, comparable even to the noble metal-based Pt/C and RuO 2 /C pair. Furthermore, the CoP NCs are employed as an air cathode in a primary zinc-air battery, exhibiting a high power density of 62 mW cm -2 and good stability. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Effects of scandium addition on iron-bearing phases and tensile properties of Al–7Si–0.6Mg alloys

    Energy Technology Data Exchange (ETDEWEB)

    Tzeng, Yu-Chih [Department of Mechanical Engineering, National Central University, Jhongli, Taiwan (China); Wu, Chih-Ting [Department of Vehicle Engineering, Army Academy R.O.C., Jhongli, Taiwan (China); Bor, Hui-Yun; Horng, Jain-Long; Tsai, Mu-Lin [Department of Mechanical Engineering, National Central University, Jhongli, Taiwan (China); Institute of Materials Science and Engineering, National Central University, Jhongli, Taiwan (China); Lee, Sheng-Long, E-mail: shenglon@cc.ncu.edu.tw [Department of Mechanical Engineering, National Central University, Jhongli, Taiwan (China); Institute of Materials Science and Engineering, National Central University, Jhongli, Taiwan (China)

    2014-01-21

    Iron is the most deleterious impurity in aluminum alloys and can easily combine with aluminum to form an acicular β-Al{sub 5}FeSi phase that reduces ductility during the solidification of the molten metal. Adding scandium (Sc) to Al–7Si–0.6Mg alloys can transform the acicular β-Al{sub 5}FeSi phase into a comparatively harmless nodular Sc–Fe phase (Al{sub 12}Si{sub 6}Fe{sub 2}(Mg,Sc){sub 5}). This Sc–Fe phase has a lower hardness and elastic modulus than the β-Al{sub 5}FeSi phase; it is thus less likely to initiate cracks in the Al matrix. Moreover, the nodular Sc–Fe phase can improve the fluidity of Al during solidification, reducing interdendritic shrinkage. Tensile testing measurements showed that the elongation of Al–7Si–0.6Mg alloys with 0.04 and 0.12 wt% Sc can be respectively increased by 115% and 110% compared to Al–7Si–0.6Mg without Sc. The corresponding quality indices are increased by 17% and 19%, respectively, suggesting that the tensile properties of Al–7Si–0.6Mg alloys can be enhanced by adding scandium.

  14. Separation of (44)Ti from proton irradiated scandium by using solid-phase extraction chromatography and design of (44)Ti/(44)Sc generator system.

    Science.gov (United States)

    Radchenko, V; Meyer, C A L; Engle, J W; Naranjo, C M; Unc, G A; Mastren, T; Brugh, M; Birnbaum, E R; John, K D; Nortier, F M; Fassbender, M E

    2016-12-16

    Scandium-44g (half-life 3.97h [1]) shows promise for positron emission tomography (PET) imaging of longer biological processes than that of the current gold standard, (18)F, due to its favorable decay parameters. One source of (44g)Sc is the long-lived parent nuclide (44)Ti (half-life 60.0 a). A (44)Ti/(44g)Sc generator would have the ability to provide radionuclidically pure (44g)Sc on a daily basis. The production of (44)Ti via the (45)Sc(p,2n) reaction requires high proton beam currents and long irradiation times. Recovery and purification of no-carrier added (nca) (44)Ti from scandium metal targets involves complex separation chemistry. In this study, separation systems based on solid phase extraction chromatography were investigated, including branched diglycolamide (BDGA) resin and hydroxamate based ZR resin. Results indicate that ZR resin in HCl media represents an effective (44)Ti/(44g)Sc separation system. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Mössbauer Spectroscopy Investigation and Hydrodesulfurization Properties of Iron–nickel Phosphide Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Gaudette, Amy F.; Burns, Autumn W.; Hayes, John R.; Smith, Mica C.; Bowker, Richard H.; Seda, Takele; Bussell, Mark E.

    2010-05-25

    Unsupported and silica-supported FexNi2-xPy catalysts having a range of metal compositions (0 < x 6 2.0) were investigated using Mössbauer spectroscopy, and the results correlated with the surface and hydrodesulfurization (HDS) properties of the supported catalysts. Mössbauer spectroscopy permits determination of the relative site occupancy of Fe atoms in tetrahedral (M(1)) and pyramidal (M(2)) sites in the FexNi2-xPy materials. Fe atoms preferentially occupy M(2) sites for materials with significant Fe contents (x > ~0.60), but the Fe site preference reverses as the Fe content decreases (x < ~0.60). Similar occupation trends are observed for the unsupported and silica-supported FexNi2-xPy materials. Thiophene HDS measurements of the FexNi2-xPy/SiO2 catalysts revealed catalysts with high Fe contents (0.80 6 x 6 2.00) to have low activities, while the activities of Ni-rich catalysts increased dramatically with increased Ni content (0.03 6 x 6 0.60). The highest HDS activity was measured for a catalyst having a nominal precursor composition of Fe0.03Ni1.97P2.00/SiO2; this catalyst was 40% more active than a optimized nickel phosphide catalyst prepared from a precursor having a nominal composition of Ni2.00P1.60/SiO2. The 25 wt.% Fe0.03Ni1.97P2.00/SiO2 catalyst also had a dibenzothiophene HDS activity just over 10% higher than that of the 25 wt.% Ni2.00P1.60/SiO2 catalyst at 548 K. The trend of increasing HDS activity for the FexNi2-xPy/ SiO2 catalysts correlates with preferential Fe occupation of M(1) sites (and, therefore, Ni occupation of M(2) sites). Supported by X-ray photoelectron spectroscopy and oxygen chemisorption measurements, we conclude that the high activity of Ni-rich FexNi2-xPy/SiO2 catalysts can be traced to a high surface density of Ni in M(2) sites that are resistant to site blockage due to S incorporation.

  16. A retrospective 7-years study of aluminum phosphide poisoning in Tehran: opportunities for prevention.

    Science.gov (United States)

    Shadnia, S; Sasanian, G; Allami, P; Hosseini, A; Ranjbar, A; Amini-Shirazi, N; Abdollahi, M

    2009-04-01

    The objective of this study was to survey aluminum phosphide (AIP) poisoning in a referral poisoning hospital in Tehran servicing an estimation of 10,000,000 populations. Records of all patients admitted and hospitalized during a period of 7 years from January 2000 to January 2007 were collected and analyzed according to gender, age, cause of intoxication, amount of AIP consumed, route of exposure, time between exposure and onset of treatment, signs and symptoms of intoxication at admission, therapeutic intervention, laboratory tests, and outcome. During the studied years, 471 patients were admitted to the hospital with AIP poisoning; 50% of them were men. The overall case fatality ratio was 31%. The mean age was 27.1 years, and most of the patients were between 20 and 40 years old. Self-poisoning was observed in 93% of cases. The average ingested dose was 5.1 g, and most of the patients (73%) consumed 1-3 tablets of AIP. A wide range of symptoms and signs was seen on admission, but the most common one was cardiovascular manifestations (78.12%). The majority (65%) of patients were from Tehran. Poisoning in spring and winter (34% and 24%, respectively) was more common than other seasons. Gastric decontamination with potassium permanganate, and administration of calcium gluconate, magnesium sulfate, sodium bicarbonate, and charcoal were considered for most of the patients. Mean arterial blood pH was 7.23 and bicarbonate concentration was 12.7 mEq/L. One-hundred percent of patients with blood pH or= 7.35 survived. Electrocardiogram (EKG) abnormalities were noted in 65.6% of cases. There was a significant difference between survival and non-survival according to pH, HCO(3) concentration, and EKG abnormality. Even without an increase in resources, there appears to be significant opportunities for reducing mortality by better medical management and further restrictions on the AIP tablets usage. Arterial blood pH seems to be a prognostic factor for the outcome of AIP

  17. Photoelectrochemical production of hydrogen from p-type transition metal phosphides

    Energy Technology Data Exchange (ETDEWEB)

    Kaenel, H. von; Gantert, L.; Hauger, R.; Wachter, P.

    1985-01-01

    A photoelectrochemical investigation of a number of p-conducting transition metal phosphide semiconductors MeP/sub 2/ (Me = Cu, Zn, Cd) is presented. The series MeP/sub 2/ can be divided into two subgroups. The first of these consists of the monoclinic compounds CuP/sub 2/ and ..beta..-ZnP/sub 2/, which appear ideally suited for photovoltaic applications, due to their bandgaps close to 1.4eV. The quantum yield of a ..beta..-ZnP/sub 2/ single crystal electrode, in 1 M Na/sub 2/S0/sub 4/ at pH 2.5, is above 60% for the polarization E chemically bondchemically bond c in a large portion of the visible and near infrared spectrum. The second class of materials are the tetragonal modifications ..cap alpha..-ZnP/sub 2/ and CdP/sub 2/. Their bandgaps are near 2.1 and 2eV, respectively. The quantum yield of ..cap alpha..-ZnP/sub 2/ is above 70% for photon energies above 2.7eV. A general feature of all these materials is the high energy of the conduction band, or conversely, the negative position of the flatband potential Vsub(fb) on the electrochemical scale. From the Mott-Schottky data for ..beta..-ZnP/sub 2/ it follows, that Vsub(fb) = -0.11 + - 0.02 Vsub(SCE) in 1 M Na/sub 2/S0/sub 4/ at pH 2.5. Photo-assisted electrolysis requires thus a rather large bias. On the other hand, hydrogen evolution can be very efficient in the presence of an electron donor. This is demonstrated with Ru0/sub 2/-loaded ..cap alpha..-ZnP/sub 2/ particles in an electrolyte containing EDTA. Due to the negative Vsub(fb) these materials could also be ideal candidates for other important redox reactions, such as C0/sub 2/ reduction. (author).

  18. Acute liver failure due to zinc phosphide containing rodenticide poisoning: Clinical features and prognostic indicators of need for liver transplantation.

    Science.gov (United States)

    Saraf, Vivek; Pande, Supriya; Gopalakrishnan, Unnikrishnan; Balakrishnan, Dinesh; Menon, Ramachandran N; Sudheer, O V; Dhar, Puneet; Sudhindran, S

    2015-07-01

    Zinc phosphide (ZnP) containing rodenticide poisoning is a recognized cause of acute liver failure (ALF) in India. When standard conservative measures fail, the sole option is liver transplantation. Records of 41 patients admitted to a single centre with ZnP-induced ALF were reviewed to identify prognostic indicators for requirement of liver transplantation. Patients were analyzed in two groups: group I (n = 22) consisted of patients who either underwent a liver transplant (n = 14) or died without a transplant (n = 8); group II (n = 19) comprised those who survived without liver transplantation. International normalized ratio (INR) in group I was 9 compared to 3 in group II (p Liver Disease (MELD) score in group I was 41 compared to 24 in group II (p liver transplantation.

  19. 25th anniversary article: exploring nanoscaled matter from speciation to phase diagrams: metal phosphide nanoparticles as a case of study.

    Science.gov (United States)

    Carenco, Sophie; Portehault, David; Boissière, Cédric; Mézailles, Nicolas; Sanchez, Clément

    2014-01-22

    The notions of nanoscale "phase speciation" and "phase diagram" are defined and discussed in terms of kinetic and thermodynamic controls, based on the case of metal phosphide nanoparticles. After an overview of the most successful synthetic routes for these exotic nanomaterials, the cases of InP, Ni2 P, Ni12 P5 and Pdx Py are discussed in detail to highlight the relationship between composition, structure, and size at the nanoscale. The influence of morphology is discussed next by comparing the behavior of Cu3 P nanophases with those of Nix Py , FeP/Fe2 P, and CoP/Co2 P. Perspectives provide the reader with methodological guidelines for further investigation of nanoscale "phase diagrams", and their use for optimized synthesis of new functional nanomaterials. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Characterization of iron doped indium phosphide as a current blocking layer in buried heterostructure quantum cascade lasers

    Science.gov (United States)

    Nida, S.; Hinkov, B.; Gini, E.; Faist, J.

    2017-03-01

    This work analyzes transport through metal organic chemical vapour deposition grown Iron doped Indium Phosphide (InP:Fe) for use as a current blocking layer in buried heterostructure Quantum Cascade Lasers. The nature of Iron incorporation in InP and electrical transport properties of InP:Fe is investigated via simulation and compared with measurement. Through simulations, we are able to predict the threshold for the onset of current rise in test structures due to avalanche injection of carriers. In addition, the benefit of InAlAs barriers inserted in InP:Fe layers is investigated and found to reduce the leakage current at lower biases while delaying the onset of avalanche. In buried heterostructure configuration, we have determined that non ideal regrowth profiles make the structure more susceptible to high field effects such as avalanche injection and trap filling that induce leakage currents.

  1. Effects of influence of carbon ring-doping on NMR parameters of boron phosphide nanotubes: A DFT study

    Directory of Open Access Journals (Sweden)

    M. Rezaei-Sameti

    2015-03-01

    Full Text Available The electronic structure of boron phosphide nanotubes (BPNTs and influence of carbon ring doping (C-doping in the horizontal region (model A and vertical region (model B of BPNTs is studied by density functional theory (DFT. At first, each form was optimized at B3LYP level of theory using 6-31G∗ bases set. After, the computed chemical shielding (CS tensors at the sites of 11B and 31P nuclei were converted to isotropic chemical shielding (CSI and anisotropic chemical shielding (CSA. The calculated results reveal that the CS parameters of B and P nuclei in C-ring doped on vertical region (model B undergo more significant changes than horizontal region (model A.

  2. Engineering a nanotubular mesoporous cobalt phosphide electrocatalyst by the Kirkendall effect towards highly efficient hydrogen evolution reactions.

    Science.gov (United States)

    Miao, Yue-E; Li, Fei; Zhou, Yu; Lai, Feili; Lu, Hengyi; Liu, Tianxi

    2017-10-19

    Tailoring the size and controlling the morphology of particular nano-architectures are considered as two promising strategies to improve the catalytic performance of metal nanocrystals towards hydrogen evolution reactions (HERs). Herein, mesoporous cobalt phosphide nanotubes (CoP-NTs) with a three-dimensional network structure have been obtained through a facile and efficient electrospinning technique combined with thermal stabilization and phosphorization treatments. The thermal stabilization process has been demonstrated to play a key role in the morphological tailoring of Co3O4 nanotubes (Co3O4-NTs). As a result, the CoP-NTs show one-dimensional hollow tubular architecture instead of forming a worm-like tubular CoP structure (W-CoP-NTs) or severely aggregated CoP powder (CoP-NPs) which originate from the Co3O4 nanotubes without thermal stabilization treatment and Co3O4 nanoparticles, respectively. Satisfyingly, under an optimized phosphorization degree, the CoP-NT electrode exhibits a low onset overpotential of 53 mV with a low Tafel slope of 50 mV dec(-1) during the HER process. Furthermore, the CoP-NT electrode is capable of driving a large cathodic current density of 10 mA cm(-2) at an overpotential of 152 mV, which is much lower than those of its contrast samples, i.e. CoP-NPs (211 mV) and W-CoP-NTs (230 mV). Therefore, this work provides a feasible and general strategy for constructing three-dimensionally organized mesoporous non-noble metal phosphide nanotubes as promising alternative high-performance electrocatalysts for the commercial platinum ones.

  3. Cationic Vacancy Defects in Iron Phosphide: A Promising Route toward Efficient and Stable Hydrogen Evolution by Electrochemical Water Splitting.

    Science.gov (United States)

    Kwong, Wai Ling; Gracia-Espino, Eduardo; Lee, Cheng Choo; Sandström, Robin; Wågberg, Thomas; Messinger, Johannes

    2017-11-23

    Engineering the electronic properties of transition metal phosphides has shown great effectiveness in improving their intrinsic catalytic activity for the hydrogen evolution reaction (HER) in water splitting applications. Herein, we report for the first time, the creation of Fe vacancies as an approach to modulate the electronic structure of iron phosphide (FeP). The Fe vacancies were produced by chemical leaching of Mg that was introduced into FeP as "sacrificial dopant". The obtained Fevacancy-rich FeP nanoparticulate films, which were deposited on Ti foil, show excellent HER activity compared to pristine FeP and Mg-doped FeP, achieving a current density of 10 mA cm -2 at overpotentials of 108 mV in 1 m KOH and 65 mV in 0.5 m H 2 SO 4 , with a near-100 % Faradaic efficiency. Our theoretical and experimental analyses reveal that the improved HER activity originates from the presence of Fe vacancies, which lead to a synergistic modulation of the structural and electronic properties that result in a near-optimal hydrogen adsorption free energy and enhanced proton trapping. The success in catalytic improvement through the introduction of cationic vacancy defects has not only demonstrated the potential of Fe-vacancy-rich FeP as highly efficient, earth abundant HER catalyst, but also opens up an exciting pathway for activating other promising catalysts for electrochemical water splitting. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  4. Gd-Sc-based mixed-metal nitride cluster fullerenes: mutual influence of the cage and cluster size and the role of scandium in the electronic structure.

    Science.gov (United States)

    Svitova, Anna L; Popov, Alexey A; Dunsch, Lothar

    2013-03-18

    The influence of the cage as well as of the cluster size has been studied in Gd-Sc nitride cluster fullerenes, which have been synthesized and isolated for these studies. A series of carbon cages ranging from C78 to C88 have been synthesized, isolated, and characterized in detail using absorption and vibrational spectroscopy as well as electrochemistry and density functional theory calculations. Gd-Sc mixed-metal cluster fullerenes in carbon cages different from C80 were described for the first time. A review of their structures, properties, and stability is given. The synthesis was performed with melamine as an effective solid source of nitrogen, providing high fullerene yield and suppressing empty fullerene formation. Substitution of gadolinium by scandium imposes a noticeable influence on the electronic structure of nitride cluster fullerenes as revealed by electrochemical, spectroscopic, and computational methods.

  5. Comparative Study on the Effectiveness of Coumavec® and Zinc Phosphide in Controlling Zoonotic Cutaneous Leishmaniasis in a Hyperendemic Focus in Central Iran

    Directory of Open Access Journals (Sweden)

    A Veysi

    2012-06-01

    Full Text Available Background: Zoonotic cutaneous leishmaniasis (ZCL is an increasing health problems in many rural areas of Iran. The aim of this study was to introduce a new alternative rodenticide to control the reservoirs of ZCL, its effect on the vector density and the incidence of the disease in hyperendemic focus of Esfa­han County, central Iran.Methods: The study was carried out from January 2011 to Janu­ary 2012. In intervention areas, rodent control operation was conducted using zinc phosphide or Coumavec®. Active case findings were done by house-to-house visits once every season during 2011–2012. To evaluate the effect of rodent control operation on the vector density, sand flies were collected twice a month using sticky traps.Results: The reduction rate of rodent holes in intervention areas with Coumavec® and zinc phosphide were 48.46% and 58.15% respectively, whereas in control area results showed 6.66 folds intensification. The Incidence of ZCL significantly reduced in the treated areas. Totally, 3200 adult sand flies were collected and identified in the inter­vention and control areas. In the treated area with zinc phosphide, the density of Phlebotomus papatasi was higher in outdoors in contrast with the treated area by Coumavec® which the density of the sand fly was higher in indoors. Conclusion: Both rodenticides were effective on the incidence of ZCL and the population of the reservoirs as well. Coumavec® seems to be effective on the outdoor density of the vector. This combination of rodenticide-insecticide could be a suitable alternative for zinc phosphide while bait shyness or behavioral resistance is occurred.

  6. Copper scandium zirconium phosphate

    DEFF Research Database (Denmark)

    Bond, Andrew David; Warner, Terence Edwin

    2013-01-01

    components. The [Sc(III)Zr(IV)(PO(4))(3)](2-) framework is composed of corner-sharing Sc/ZrO(6) octahedra and PO(4) tetrahedra. The Sc and Zr atoms are disordered on one atomic site on a crystallographic threefold axis. The P atom of the phosphate group lies on a crystallographic twofold axis. Nonframework...

  7. Synthesis and characterization of reduced scandium halide containing one- and two-dimensional metal bonded arrays. [Sc--ScCl3; Cs3Sc2Cl9; CsScCl3

    Energy Technology Data Exchange (ETDEWEB)

    Poeppelmeier, K.R.

    1978-08-01

    The stabilization effect of metal-metal bond formation on reduced scandium compounds was studied. The binary compounds Sc/sub 7/Cl/sub 12/, Sc/sub 5/Cl/sub 8/, Sc/sub 7/Cl/sub 10/ and ScCl were prepared by high temperature techniques and were characterized by single crystal x-ray diffraction. The respective metal arrays in these compounds can be viewed as fragments of scandium metal ranging from discrete six atom metal cluster species (Sc(Sc/sub 6/Cl/sub 12/)), through intermediate single and double infinite chain configurations ((ScCl/sub 2/)(Sc/sub 4/Cl/sub 6/)) and ((ScCl/sub 2/)(Sc/sub 6/Cl/sub 8/)) to double metal close-packed sheets (ScCl). The halogen atoms effectively isolate the clusters, chains and sheets by bonding face, edge or exo positions on the metal arrays. The common occurrence of isolated scandium (III) ions emphasizes that a minimum number of bonding electrons is required to stabilize what are formally anionic metal arrays. The distribution of the reduction electrons in these anisotropic materials was studied by magnetic susceptibility, EPR and uv-X photoelectron spectroscopy. The ternary compounds studied were Cs/sub 3/Sc/sub 2/Cl/sub 9/ and CsScCl/sub 3/. The anion-bridged metal chain of the hexagonal perovskite structure was found to stabilize scandium (II). CsScCl/sub 3/ was found to be grossly nonstoichiometric on the transition metal site and the effects of the mixed valence character were studied between the single valence extremes Cs/sub 3/Sc/sub 2 + x/Cl/sub 9/; 0< x < 1.0.

  8. Chemical Reaction between Boric Acid and Phosphine Indicates Boric Acid as an Antidote for Aluminium Phosphide Poisoning

    Directory of Open Access Journals (Sweden)

    Motahareh Soltani

    2016-08-01

    Full Text Available Objectives: Aluminium phosphide (AlP is a fumigant pesticide which protects stored grains from insects and rodents. When it comes into contact with moisture, AlP releases phosphine (PH3, a highly toxic gas. No efficient antidote has been found for AlP poisoning so far and most people who are poisoned do not survive. Boric acid is a Lewis acid with an empty p orbital which accepts electrons. This study aimed to investigate the neutralisation of PH3 gas with boric acid. Methods: This study was carried out at the Baharlou Hospital, Tehran University of Medical Sciences, Tehran, Iran, between December 2013 and February 2014. The volume of released gas, rate of gas evolution and changes in pH were measured during reactions of AlP tablets with water, acidified water, saturated boric acid solution, acidified saturated boric acid solution, activated charcoal and acidified activated charcoal. Infrared spectroscopy was used to study the resulting probable adduct between PH3 and boric acid. Results: Activated charcoal significantly reduced the volume of released gas (P <0.01. Although boric acid did not significantly reduce the volume of released gas, it significantly reduced the rate of gas evolution (P <0.01. A gaseous adduct was formed in the reaction between pure AlP and boric acid. Conclusion: These findings indicate that boric acid may be an efficient and non-toxic antidote for PH3 poisoning.

  9. A review of episodes of zinc phosphide toxicosis in wild geese (Branta spp.) in Oregon (2004−2011)

    Science.gov (United States)

    Bildfell, Rob J.; Rumbeiha, Wilson K.; Schuler, Krysten L.; Meteyer, Carol U.; Wolff, Peregrine L.; Gillin, Colin M.

    2013-01-01

    Epizootic mortality in several geese species, including cackling geese (Branta hutchinsii) and Canada geese (Branta canadensis), has been recognized in the Willamette Valley of Oregon for over a decade. Birds are generally found dead on a body of water or are occasionally observed displaying neurologic clinical signs such as an inability to raise or control the head prior to death. Investigation of these epizootic mortality events has revealed the etiology to be accidental poisoning with the rodenticide zinc phosphide (Zn3P2). Gross and histologic changes are restricted to acute pulmonary congestion and edema, sometimes accompanied by distension of the upper alimentary tract by fresh grass. Geese are unusually susceptible to this pesticide; when combined with an epidemiologic confluence of depredation of specific agricultural crops by rodents and seasonal avian migration pathways, epizootic toxicosis may occur. Diagnosis requires a high index of suspicion, appropriate sample collection and handling, plus specific test calibration for this toxicant. Interagency cooperation, education of farmers regarding pesticide use, and enforcement of regulations has been successful in greatly decreasing these mortality events since 2009.

  10. 4x4 planar array antenna on indium phosphide substrate for 0.3-THz band application

    Science.gov (United States)

    Kanaya, Haruichi; Koga, Masahiko; Tsugami, Kota; Eu, Guan Chai; Kato, Kazutoshi

    2017-02-01

    This paper presents a design and fabrication of 4 × 4 one-sided directional slot array antenna on indium phosphide (InP) substrate for 0.3 THz (300 GHz) wireless link. The antenna has top antenna metal layer and bottom floating metal layer. Polyimide dielectric layer is stacked between each metal layer. The antenna is placed on the deep etched InP substrate. By optimizing the length of the bottom floating metal layer, one-sided directional radiation can be realized. The branched coplanar wave guide (CPW) transmission line is connected to each antenna element with the same electrical length. The size of the 4 × 4 array antenna is 2,730 μm x 3,000 μm with uni-traveling-carrier photodiodes, DC bias and ground lines. Simulated realized gain in peak direction of the proposed antenna is 11.7 dBi. The transmission measurement is carried and measured received power.

  11. PLEURAL EFFECTS OF INDIUM PHOSPHIDE IN B6C3F1 MICE: NONFIBROUS PARTICULATE INDUCED PLEURAL FIBROSIS

    Science.gov (United States)

    Kirby, Patrick J.; Shines, Cassandra J.; Taylor, Genie J.; Bousquet, Ronald W.; Price, Herman C.; Everitt, Jeffrey I.; Morgan, Daniel L.

    2010-01-01

    The mechanism(s) by which chronic inhalation of indium phosphide (InP) particles causes pleural fibrosis is not known. Few studies of InP pleural toxicity have been conducted because of the challenges in conducting particulate inhalation exposures, and because the pleural lesions developed slowly over the 2-year inhalation study. The authors investigated whether InP (1 mg/kg) administered by a single oropharyngeal aspiration would cause pleural fibrosis in male B6C3F1 mice. By 28 days after treatment, protein and lactate dehydrogenase (LDH) were significantly increased in bronchoalveolar lavage fluid (BALF), but were unchanged in pleural lavage fluid (PLF). A pronounced pleural effusion characterized by significant increases in cytokines and a 3.7-fold increase in cell number was detected 28 days after InP treatment. Aspiration of soluble InCl3 caused a similar delayed pleural effusion; however, other soluble metals, insoluble particles, and fibers did not. The effusion caused by InP was accompanied by areas of pleural thickening and inflammation at day 28, and by pleural fibrosis at day 98. Aspiration of InP produced pleural fibrosis that was histologically similar to lesions caused by chronic inhalation exposure, and in a shorter time period. This oropharyngeal aspiration model was used to provide an initial characterization of the progression of pleural lesions caused by InP. PMID:19995279

  12. High energy oxygen irradiation-induced defects in Fe-doped semi-insulating indium phosphide by positron annihilation technique

    Science.gov (United States)

    Pan, S.; Mandal, A.; Sohel, Md. A.; Saha, A. K.; Das, D.; Sen Gupta, A.

    2017-02-01

    Positron annihilation technique is applied to study the recovery of radiation-induced defects in 140 MeV oxygen (O6+) irradiated Fe-doped semi-insulating indium phosphide during annealing over a temperature region of 25∘C-650∘C. Lifetime spectra of the irradiated sample are fitted with three lifetime components. Trapping model analysis is used to characterize defect states corresponding to the de-convoluted lifetime values. After irradiation, the observed average lifetime of positron τavg = 263 ps at room temperature is higher than the bulk lifetime by 21 ps which reveals the presence of radiation-induced defects in the material. A decrease in τavg occurs during room temperature 25∘C to 200∘C indicating the dissociation of higher order defects, might be due to positron trapping in acceptor-type of defects (VIn). A reverse annealing stage is found at temperature range of 250∘C-425∘C for S-parameter probably due to the migration of vacancies and the formation of vacancy clusters. Increase in R-parameter from 325∘C to 425∘C indicates the change in the nature of predominant positron trapping sites. Beyond 425∘C, τavg, S-parameter and R-parameter starts decreasing and around 650∘C, τavg and S-parameter approached almost the bulk value showing the annealing out of radiation-induced defects.

  13. Chemical Reaction between Boric Acid and Phosphine Indicates Boric Acid as an Antidote for Aluminium Phosphide Poisoning.

    Science.gov (United States)

    Soltani, Motahareh; Shetab-Boushehri, Seyed F; Shetab-Boushehri, Seyed V

    2016-08-01

    Aluminium phosphide (AlP) is a fumigant pesticide which protects stored grains from insects and rodents. When it comes into contact with moisture, AlP releases phosphine (PH3), a highly toxic gas. No efficient antidote has been found for AlP poisoning so far and most people who are poisoned do not survive. Boric acid is a Lewis acid with an empty p orbital which accepts electrons. This study aimed to investigate the neutralisation of PH3 gas with boric acid. This study was carried out at the Baharlou Hospital, Tehran University of Medical Sciences, Tehran, Iran, between December 2013 and February 2014. The volume of released gas, rate of gas evolution and changes in pH were measured during reactions of AlP tablets with water, acidified water, saturated boric acid solution, acidified saturated boric acid solution, activated charcoal and acidified activated charcoal. Infrared spectroscopy was used to study the resulting probable adduct between PH3 and boric acid. Activated charcoal significantly reduced the volume of released gas (P boric acid did not significantly reduce the volume of released gas, it significantly reduced the rate of gas evolution (P boric acid. These findings indicate that boric acid may be an efficient and non-toxic antidote for PH3 poisoning.

  14. Scandium functionalized carbon aerogel: Synthesis of nanoparticles and structure of a new ScOCl and properties of NaAlH{sub 4} as a function of pore size

    Energy Technology Data Exchange (ETDEWEB)

    Javadian, Payam; Nielsen, Thomas K. [Center for Energy Materials, Interdisciplinary Nanoscience Center (iNANO), and Department of Chemistry, Aarhus University, DK-8000 Aarhus (Denmark); Ravnsbæk, Dorthe B. [Department of Material Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge 02142, MA (United States); Jepsen, Lars H. [Center for Energy Materials, Interdisciplinary Nanoscience Center (iNANO), and Department of Chemistry, Aarhus University, DK-8000 Aarhus (Denmark); Polanski, Marek [Faculty of Advanced Technology and Chemistry, Military University of Technology, 2 Kaliskiego Str., 00-908 Warsaw (Poland); Plocinski, Tomasz [Faculty of Material Science and Engineering, Warsaw University of Technology, 144 Woloska Str., 02-507 Warsaw (Poland); Kunce, Izabela [Faculty of Advanced Technology and Chemistry, Military University of Technology, 2 Kaliskiego Str., 00-908 Warsaw (Poland); Besenbacher, Flemming [Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Bystrzycki, Jerzy [Faculty of Advanced Technology and Chemistry, Military University of Technology, 2 Kaliskiego Str., 00-908 Warsaw (Poland); Jensen, Torben R., E-mail: trj@chem.au.dk [Center for Energy Materials, Interdisciplinary Nanoscience Center (iNANO), and Department of Chemistry, Aarhus University, DK-8000 Aarhus (Denmark)

    2015-11-15

    A new method for scandium-functionalization of carbon aerogels forming nanoparticles of a new scandiumoxochloride, ScOCl is presented. Sodium aluminiumhydride, NaAlH{sub 4}, is successfully melt infiltrated into the nano porous scaffolds with pore sizes of D{sub max}=7, 10, 13, 21, 26 and 39 nm, containing scandium based nano particles (<2.9 wt%) confirmed by elemental analysis and scanning electron microscopy. A systematic study of hydrogen storage properties of the nano composite materials is presented. An aqueous solution of ScCl{sub 3} was initially infiltrated and formed nanoconfined [Sc(OH)(H{sub 2}O){sub 5}]{sub 2}Cl{sub 4}(H{sub 2}O){sub 2}, which transforms to nanoparticles of a new scandium oxochloride, ScOCl at 192 °C and to Sc{sub 2}O{sub 3} at 420 °C. ScOCl crystallizes in an orthorhombic unit cell a=3.4409(8), b=3.9613(6) and c=8.178(2) Å, space group Pmmn, and is built from layers of [ScO{sub 4}Cl{sub 2}] octahedra forming neutral ScOCl layers. Temperature programmed desorption mass spectroscopy shows slightly improved kinetics for release of hydrogen with decreasing pore size. Continuous cycling of hydrogen release and uptake measured by the Sieverts' method reveal a larger preserved hydrogen storage capacity for scandium-functionalized aerogel with the larger pores (39 nm). - Highlights: • New synthesis approach for nanoporous Sc-functionalization carbon aerogel (Sc-CA). • The new scandium oxochloride, ScOCl, structure is obtained. • NaAlH{sub 4} nanoconfined in Sc-CA with pores ranging between 7 nm

  15. The use of the erbium, chromium:yttrium-scandium-gallium-garnet laser in endodontic treatment: the results of an in vitro study.

    Science.gov (United States)

    Schoop, Ulrich; Goharkhay, Kawe; Klimscha, Johannes; Zagler, Manuela; Wernisch, Johann; Georgopoulos, Apostolos; Sperr, Wolfgang; Moritz, Andreas

    2007-07-01

    The use of the erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser has become accepted in the field of cavity preparation. The development of miniaturized and flexible fiber tips has allowed this device to be used in endodontics. The authors conducted an in vitro study to assess the effects of Er,Cr:YSGG laser irradiation on root canals. The authors inoculated root canals with two bacteria, laser irradiated them at two power settings and subjected them to a quantitative microbiological evaluation. They used scanning electron microscopy (SEM) to assess morphological changes in endodontically processed and laser-irradiated root canal walls. They measured temperature increases on the root surface to determine possible thermal side effects. The bacteriological evaluation revealed a disinfecting effect in the root dentin samples that was dependent on the output power but not specific for the bacterial species investigated. SEM showed the removal of the smear layer from the root canal walls and the exposure of dentinal tubules. The temperature rise during irradiation was moderate when standardized power settings were used. The Er,Cr:YSGG laser can be used to eliminate bacteria in root canals. It also effectively removes smear layer and debris from the canal wall. Practitioners can use the Er,Cr:YSGG laser to prepare root canals for endodontic therapy.

  16. Aluminum-Scandium Alloys: Material Characterization, Friction Stir Welding, and Compatibility With Hydrogen Peroxide (MSFC Center Director's Discretionary Fund Final Report, Proj. No. 04-14)

    Science.gov (United States)

    Lee, J. A.; Chen, P. S.

    2004-01-01

    This Technical Memorandum describes the development of several high-strength aluminum (Al) alloys that are compatible with hydrogen peroxide (H2O2) propellant for NASA Hypersonic-X (Hyper-X) vehicles fuel tanks and structures. The yield strengths for some of these Al-magnesium-based alloys are more than 3 times stronger than the conventional 5254-H112 Al alloy, while maintaining excellent H2O2 compatibility similar to class 1 5254 alloy. The alloy development strategy is to add scandium, zirconium, and other transitional metals with unique electrochemical properties, which will not act as catalysts, to decompose the highly concentrated 90 percent H2O2. Test coupons are machined from sheet metals for H2O2 long-term exposure testing and mechanical properties testing. In addition, the ability to weld the new alloys using friction stir welding has also been explored. The new high-strength alloys could represent an enabling material technology for Hyper-X vehicles, where flight weight reduction is a critical requirement.

  17. High-fluence and high-density treatment of perioral rhytides using a new, fractionated 2,790-nm ablative erbium-doped Yttrium Scandium Gallium Garnet Laser.

    Science.gov (United States)

    Ciocon, David H; Hussain, Mussarat; Goldberg, David J

    2011-06-01

    In this study, we evaluated the safety and efficacy of a novel 2,790-nm erbium-doped yttrium scandium gallium garnet (Er:YSGG) laser system for the treatment of facial photodamage and perioral wrinkles using a single-treatment, high-fluence, high-density protocol. Eleven female participants with Fitzpatrick skin types II to III and facial wrinkles underwent a single full-face fractional ablative treatment with a 2,790-nm Er:YSGG laser. Follow-up visits were completed at 1, 2, and 6 weeks 3 and 6 months. Quartile improvement scale (0-4) and Fitzpatrick wrinkle scores (1-9) were used for the assessments. Based on blinded photographic assessments, the mean difference in Fitzpatrick wrinkle scores for full face wrinkles was 1.5 ± 1.2 (a reduction from 6.6 to 5.1; paired t-test, p = .003). There was also a statistically significant mean reduction of 1.7 ± 1.3 in perioral wrinkle scores (from 6.7 to 5.0; p = .002). No serious adverse events were reported. A novel, fractionated, ablative 2,790-nm Er:YSGG laser can safely and effectively treat photodamage and perioral wrinkles in a single treatment using a high-fluence, high-density protocol. Cutera provided the equipment used in this study and funding to Dr. Goldberg. © 2011 by the American Society for Dermatologic Surgery, Inc.

  18. Impact of layer and substrate properties on the surface acoustic wave velocity in scandium doped aluminum nitride based SAW devices on sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Gillinger, M., E-mail: manuel.gillinger@tuwien.ac.at; Knobloch, T.; Schneider, M.; Schmid, U. [Institute of Sensor and Actuator Systems, TU Wien, 1040 Vienna (Austria); Shaposhnikov, K.; Kaltenbacher, M. [Institute of Mechanics and Mechatronics, TU Wien, 1040 Vienna (Austria)

    2016-06-06

    This paper investigates the performance of surface acoustic wave (SAW) devices consisting of reactively sputter deposited scandium doped aluminum nitride (Sc{sub x}Al{sub 1-x}N) thin films as piezoelectric layers on sapphire substrates for wireless sensor or for RF-MEMS applications. To investigate the influence of piezoelectric film thickness on the device properties, samples with thickness ranging from 500 nm up to 3000 nm are fabricated. S{sub 21} measurements and simulations demonstrate that the phase velocity is predominantly influenced by the mass density of the electrode material rather than by the thickness of the piezoelectric film. Additionally, the wave propagation direction is varied by rotating the interdigital transducer structures with respect to the crystal orientation of the substrate. The phase velocity is about 2.5% higher for a-direction compared to m-direction of the sapphire substrate, which is in excellent agreement with the difference in the anisotropic Young's modulus of the substrate corresponding to these directions.

  19. Molecular fingerprint-region spectroscopy from 5-12 \\mu m using an orientation-patterned gallium phosphide optical parametric oscillator

    CERN Document Server

    Maidment, Luke; Reid, Derryck T

    2016-01-01

    We report a femtosecond optical parametric oscillator (OPO) based on the new semiconductor gain material orientation patterned gallium phosphide (OP-GaP), which enables the production of high-repetition-rate femtosecond pulses spanning 5-12 \\mu m with average powers in the few to tens of milliwatts range. This is the first example of a broadband OPO operating across the molecular fingerprint region, and we demonstrate its potential by conducting broadband Fourier-transform spectroscopy using water vapor and a polystyrene reference standard.

  20. Hierarchical cobalt poly-phosphide hollow spheres as highly active and stable electrocatalysts for hydrogen evolution over a wide pH range

    Science.gov (United States)

    Wu, Tianli; Pi, Mingyu; Wang, Xiaodeng; Guo, Weimeng; Zhang, Dingke; Chen, Shijian

    2018-01-01

    Exploring highly-efficient and low-cost non-noble metal electrocatalyst toward the hydrogen evolution reaction (HER) is highly desired for renewable energy system but remains challenging. In this work, three dimensional hierarchical porous cobalt poly-phosphide hollow spheres (CoP3 HSs) were prepared by topotactic phosphidation of the cobalt-based precursor via vacuum encapsulation technique. As a porous HER cathode, the CoP3 HSs delivers remarkable electrocatalytic performance over the wide pH range. It needs overpotentials of -69 mV and -118 mV with a small Tafel slope of 51 mV dec-1 to obtain current densities of 10 mA cm-2 and 50 mA cm-2, respectively, and maintains its electrocatalytic performance over 30 h in acidic solution. In addition, CoP3 also exhibit superior electrocatalytic performance and stability under neutral and alkaline conditions for the HER. Both experimental measurements and density functional theory (DFT) calculations are performed to explore the mechanism behind the excellent HER performance. The results of our study make the porous CoP3 HSs as a promising electrocatalyst for practical applications toward energy conversion system and present a new way for designing and fabricating HER electrodes through high degree of phosphorization and nano-porous architecture.

  1. Structure and temperature effects on Nd3+ spectra in polycrystalline mixed scandium aluminum garnets Y3ScxAl5-xO12

    Science.gov (United States)

    Lupei, A.; Lupei, V.; Hau, S.; Gheorghe, C.; Voicu, F.

    2015-09-01

    New spectroscopic data obtained from high resolution low temperature absorption and emission spectra of Nd3+ in mixed scandium aluminum garnets Y3ScxAl5-xO12 - (x = 0-2) translucent ceramics revealed transition dependent composition effects: modification of the shapes (Lorentz at x = 0 and 2, quasi-Gauss at x = 1, x-dependent asymmetric for other x values, with obvious multicenter structure for low x), widths and shifts of the lines. Nd3+ electronic structure dependence on structural changes with composition is analyzed in terms of nephelauxetic effect and maximum splitting of manifolds: Sc3+ co-doping reduces the nephelauxetic effect, and the increase of 4F3/2 splitting from 85 cm-1 (x = 0) to 98 cm-1 (x = 2) denotes the lowering of local symmetry. The multicenter structure and inhomogeneous broadening of Nd3+ lines is attributed to crystal field distributions determined by the random occupancy of the octahedral sites by Sc3+ and Al3+. For low x (0.2) the resolved two satellites S1, S2 that accompany Nd:YAG lines are correlated to anisotropic crystal field perturbations produced by the n.n. Sc3+ by analogy to those determined by Y3+-antisites (excess of Y3+ ions that enter in octahedral sites of the melt-grown YAG crystals). The temperature evolution of the Nd3+ spectral characteristics (line intensity, shift, broadening) in the 10-300 K range is analyzed in terms of thermal population of the Stark levels, of the effect on electron-phonon interaction and on lattice expansion. The relevance of the spectroscopic properties on the laser emission characteristics in these systems is discussed.

  2. Dissolved scandium, yttrium, and lanthanum in the surface waters of the North Atlantic: Potential use as an indicator of scavenging intensity

    Science.gov (United States)

    Till, C. P.; Shelley, R. U.; Landing, W. M.; Bruland, K. W.

    2017-08-01

    Recent work has begun to elucidate the biogeochemical cycling of scandium (Sc) in the open ocean, but so far no surface distribution data have been reported of dissolved Sc, and no basin-scale surface distributions have been reported of yttrium (Y) or lanthanum (La). This work presents basin-wide surface Sc, Y, and La data in a section across the North Atlantic subtropical gyre (2011 GEOTRACES GA03) and investigates the potential utility of these distributions. This work uses dissolved and aerosol concentration data for La and Sc to estimate their surface ocean residence times in both the center of the oligotrophic gyre and near the African coastline. This work additionally shows that the surface distribution of Sc in the North Atlantic correlates with the shape of the gyre as inferred by isotherm depth, with lower Sc concentrations at the gyre boundaries. This pattern suggests that Sc could be drawn down by the elevated particle flux at the gyre boundaries. In this case, Sc removal could be used as an indicator of scavenging intensity. In order to account for variable input of Sc to the surface ocean, we propose normalizing the Sc distribution to that of Y or La, which are much less particle reactive and are input via dust to the surface North Atlantic in constant ratios with Sc. Such normalization improves the correlation with isotherm depth. We propose that the variations in dissolved Y/Sc and La/Sc ratios may be due to preferential Sc scavenging and could therefore indicate scavenging intensity.

  3. On new ternary equiatomic scandium transition metal aluminum compounds ScTAl with T = Cr, Ru, Ag, Re, Pt, and Au

    Energy Technology Data Exchange (ETDEWEB)

    Radzieowski, Mathis; Janka, Oliver [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Benndorf, Christopher [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Muenster Univ. (Germany). Inst. fuer Physikalische Chemie; Haverkamp, Sandra [Muenster Univ. (Germany). Inst. fuer Physikalische Chemie; Eckert, Hellmut [Muenster Univ. (Germany). Inst. fuer Physikalische Chemie; University of Sao Paulo, Sao Carlos, SP (Brazil). Inst. of Physics

    2016-08-01

    The new equiatomic scandium transition metal aluminides ScTAl for T = Cr, Ru, Ag, Re, Pt, and Au were obtained by arc-melting of the elements followed by subsequent annealing for crystal growth. The samples were studied by powder and single crystal X-ray diffraction. The structures of three compounds were refined from single crystal X-ray diffractometer data: ScCrAl, MgZn{sub 2} type, P6{sub 3}/mmc, a = 525.77(3), c = 858.68(5) pm, R{sub 1} = 0.0188, wR{sub 2} = 0.0485, 204 F{sup 2} values, 13 variables, ScPtAl, TiNiSi type, Pnma, a = 642.83(4), b = 428.96(2), c = 754.54(5) pm, R{sub 1} = 0.0326, wR{sub 2} = 0.0458, 448 F{sup 2} values, 20 variables and ScAuAl, HfRhSn type, P anti 62c, a = 722.88(4), c = 724.15(4) pm, R{sub 1} = 0.0316, wR{sub 2} = 0.0653, 512 F{sup 2} values, 18 variables. Phase pure samples of all compounds were furthermore investigated by magnetic susceptibility measurements, and Pauli-paramagnetism but no superconductivity was observed down to 2.1 K for all of them. The local structural features and disordering phenomena have been characterized by {sup 27}Al and {sup 45}Sc magic angle spinning (MAS) and static NMR spectroscopic investigations.

  4. Treatment of infraorbital dark circles in atopic dermatitis with a 2790-nm erbium: yttrium scandium gallium garnet laser: a pilot study.

    Science.gov (United States)

    Park, Kui Young; Oh, In Young; Moon, Nam Ju; Seo, Seong Jun

    2013-04-01

    Although many Asian atopic patients have orbital darkening symptom and the demand to treat this condition is increasing, little has been reported in the literature on the treatment of infraorbital dark circles in atopic dermatitis. To evaluate the clinical efficacy and safety of 2790-nm erbium:yttrium scandium gallium garnet (Er:YSGG) laser therapy for reducing infraorbital dark circles in atopic dermatitis patients. Ten Korean patients over 21 year with mild atopic dermatitis and infraorbital dark circles were enrolled in this study. Patients who need active atopic dermatitis treatments are excluded because of the possibility of aggravation after laser treatment. They were treated for dark circles using a 2790-nm Er:YSGG laser. The treatment parameters were 1.8-2.2 J/cm² fluence, 6-mm spot size, and 0.3-ms pulse width with 10% overlap over the infraorbital areas once with a 4-week interval between treatments. Efficacy was assessed with a quartile grading score ranging from 0 to 5 by a blinded investigator, and the patients also documented their degree of satisfaction with the same grading score. All possible side effects were evaluated. The clinical assessment showed 74.5% (2.7) and 72.5% (2.5) improvements, and the patient satisfaction scale scores improved an average of 74% (2.4) and 71.5% (2.3) at 2 months and 4 months after treatment, respectively. There were no severe side effects or aggravation of atopic dermatitis. Our study suggests that 2790-nm Er:YSGG laser therapy can be effectively and safely used in the treatment of infraorbital dark circles in atopic dermatitis patients.

  5. The influence of cation ordering, oxygen vacancy distribution and proton siting on observed properties in ceramic electrolytes: the case of scandium substituted barium titanate.

    Science.gov (United States)

    Torino, Nico; Henry, Paul F; Knee, Christopher S; Bjørheim, Tor Svendsen; Rahman, Seikh M H; Suard, Emma; Giacobbe, Carlotta; Eriksson, Sten G

    2017-07-04

    The origin of the 2-order of magnitude difference in the proton conductivity of the hydrated forms of hexagonal and cubic oxygen deficient BaScxTi1-xO3-δ (x = 0.2 and x = 0.7) was probed using a combination of neutron diffraction and density functional theory techniques to support published X-ray diffraction, conductivity, thermogravimetric and differential scanning calorimetry studies. Cation ordering is found in the 6H structure type (space group P63/mmc) adopted by BaSc0.2Ti0.8O3-δ with scandium preferentially substituting in the vertex sharing octahedra (2a crystallographic site) and avoiding the face-sharing octahedra (4f site). This is coupled with oxygen vacancy ordering in the central plane of the face-sharing octahedra (O1 site). In BaSc0.7Ti0.3O3-δ a simple cubic perovskite (space group Pm3[combining macron]m) best represents the average structure from Rietveld analysis with no evidence of either cation ordering or oxygen vacancy ordering. Significant diffuse scattering is observed, indicative of local order. Hydration in both cases leads to complete filling of the available oxygen vacancies and permits definition of the proton sites. We suggest that the more localised nature of the proton sites in the 6H structure is responsible for the significantly lower proton conduction observed in the literature. Within the 6H structure type final model, proton diffusion requires a 3-step process via higher energy proton sites that are unoccupied at room temperature and is also likely to be anisotropic whereas the highly disordered cubic perovskite proton position allows 3-dimensional diffusion by well-described modes. Finally, we propose how this knowledge can be used to further materials design for ceramic electrolytes for proton conducting fuel cells.

  6. Hessian Fly (Diptera: Cecidomyiidae) Mortality in Export Bale Compressors and Response to a Hydrogen Phosphide and Carbon Dioxide Gas Mixture.

    Science.gov (United States)

    Yokoyama, Victoria Y; Cambron, Sue E; Muhareb, Jeannette

    2015-02-01

    Hessian fly, Mayetiola destructor (Say), puparial mortality was evaluated in three modern hay compressors that produce compressed standard and large-size bales for export to Asia-Pacific countries. Pressure on bales ranged from 93.4 to 139.4 kg/cm2, causing 90.0-99.9% mortality of 10,891-23,164 puparia. Puparial response to a cylinderized hydrogen phosphide (1.8-2%) and carbon dioxide (97.8-98%) gas mixture was evaluated as a potential quarantine treatment using 2-4 d-exposures to low, medium, and high doses of 0.73-0.86, 1.05-1.26, and 1.39-1.56 mg/liter, and temperatures of 5.87±1.14, 9.84±0.05, 16.14±0.14, and 20.35±0.11°C. Accumulative concentration multiplied by time products (mg h/liter) at all fumigation temperatures for low, medium, and high fumigant doses were 34.9-37.7, 52.2-54.3, and 67.9-73.1 for 2 d; 52.7-60.6, 77.9-89.2, and 102.1-110.7 for 3 d; and 69.9-82.0, 99.4-118.2, and 132.3-146.8 for 4 d, respectively. An increase in mortality was significantly related to an increase in fumigation duration at 5, 10, and 15°C, and an increase in fumigant dose at 10 and 15°C. Puparial mortality ranged from 97.2 to 100% at all doses and durations at 20°C with no survivors at the highest dose for 3 d and the mid- and highest dose for 4 d. Bale compression is currently used in the first phase of a multiple quarantine treatment to control potential Hessian fly contaminants in exported hay. The novel fumigant may have application as a single quarantine treatment for noncompressed, standard exported bales. Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.

  7. Results from Coupled Optical and Electrical Sentaurus TCAD Models of a Gallium Phosphide on Silicon Electron Carrier Selective Contact Solar Cell

    Energy Technology Data Exchange (ETDEWEB)

    Limpert, Steven; Ghosh, Kunal; Wagner, Hannes; Bowden, Stuart; Honsberg, Christiana; Goodnick, Stephen; Bremner, Stephen; Green, Martin

    2014-06-09

    We report results from coupled optical and electrical Sentaurus TCAD models of a gallium phosphide (GaP) on silicon electron carrier selective contact (CSC) solar cell. Detailed analyses of current and voltage performance are presented for devices having substrate thicknesses of 10 μm, 50 μm, 100 μm and 150 μm, and with GaP/Si interfacial quality ranging from very poor to excellent. Ultimate potential performance was investigated using optical absorption profiles consistent with light trapping schemes of random pyramids with attached and detached rear reflector, and planar with an attached rear reflector. Results indicate Auger-limited open-circuit voltages up to 787 mV and efficiencies up to 26.7% may be possible for front-contacted devices.

  8. Polyaniline Derived N-Doped Carbon-Coated Cobalt Phosphide Nanoparticles Deposited on N-Doped Graphene as an Efficient Electrocatalyst for Hydrogen Evolution Reaction.

    Science.gov (United States)

    Ma, Jingwen; Wang, Min; Lei, Guangyu; Zhang, Guoliang; Zhang, Fengbao; Peng, Wenchao; Fan, Xiaobin; Li, Yang

    2018-01-01

    The development of highly efficient and durable non-noble metal electrocatalysts for the hydrogen evolution reaction (HER) is significant for clean and renewable energy research. This work reports the synthesis of N-doped graphene nanosheets supported N-doped carbon coated cobalt phosphide (CoP) nanoparticles via a pyrolysis and a subsequent phosphating process by using polyaniline. The obtained electrocatalyst exhibits excellent electrochemical activity for HER with a small overpotential of -135 mV at 10 mA cm-2 and a low Tafel slope of 59.3 mV dec-1 in 0.5 m H2 SO4 . Additionally, the encapsulation of N-doped carbon shell prevents CoP nanoparticles from corrosion, exhibiting good stability after 14 h operation. Moreover, the as-prepared electrocatalyst also shows outstanding activity and stability in basic and neutral electrolytes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Design and fabrication of anti-reflection coating on Gallium Phosphide, Zinc Selenide and Zinc Sulfide substrates for visible and infrared application

    Directory of Open Access Journals (Sweden)

    Mokrý P.

    2013-05-01

    Full Text Available Results of design and fabrication of a dual-band anti-reflection coating on a gallium phosphide (GaP, zinc selenide (ZnSe and zinc sulfide (ZnS substrates are presented. A multilayer stack structure of antireflection coatings made of zinc sulfide and yttrium fluoride (YF3 was theoretically designed for optical bands between 0.8 and 0.9 μm and between 9.5 and 10.5 μm. This stack was designed as efficient for these materials (GaP, ZnS, ZnSe together. Multilayer stack structure was deposited using thermal evaporation method. Theoretically predicted transmittance spectra were compared with transmitted spectra measured on coated substrates. Efficiency of anti-reflection coating is estimated and discrepancies are analyzed and discussed.

  10. Effects of erbium-and chromium-doped yttrium scandium gallium garnet and diode lasers on the surfaces of restorative dental materials: a scanning electron microscope study.

    Science.gov (United States)

    Hatipoglu, M; Barutcigil, C

    2015-01-01

    The aim of this study is to evaluate the potential effects of laser irradiation, which is commonly performed in periodontal surgery, on the surfaces of restorative materials. Five different restorative dental materials were used in this study, as follows: (1) Resin composite, (2) poly acid-modified resin composite (compomer), (3) conventional glass ionomer cement (GIC), (4) resin-modified glass ionomer cement (RMGIC), and (5) amalgam. Four cylindrical samples (8 mm diameter, 2 mm height) were prepared for each restorative material. In addition, four freshly extracted, sound human incisors teeth were selected. Two different laser systems commonly used in periodontal surgery were examined in this study: A 810 nm diode laser at a setting of 1 W with continuous-phase laser irradiation for 10 s, and an erbium-and chromium-doped yttrium scandium gallium garnet (Er, Cr: YSGG) laser at settings of 2.5 W, 3.25 W, and 4 W with 25 Hz laser irradiation for 10 s. Scanning electron microscopy (SEM) analysis was performed to evaluate the morphology and surface deformation of the restorative materials and tooth surfaces. According to the SEM images, the Er, Cr: YSGG laser causes irradiation markings that appear as demineralized surfaces on tooth samples. The Er, Cr: YSGG laser also caused deep defects on composite, compomer, and RMGIC surfaces because of its high power, and the ablation was deeper for these samples. High-magnification SEM images of GIC samples showed the melting and combustion effects of the Er, Cr: YSGG laser, which increased as the laser power was increased. In amalgam samples, neither laser left significant harmful effects at the lowest power setting. The diode laser did cause irradiation markings, but they were insignificant compared with those left by the Er, Cr: YSGG laser on the surfaces of the different materials and teeth. Within the limitations of this study, it can be concluded that Er, Cr: YSGG laser irradiation could cause distortions of the surfaces

  11. Synthesis and characterization of low-valence actinide phosphide tellurides and ternary selenium-halide iridium complexes; Synthese und Charakterisierung niedervalenter Actinoidphosphidtelluride und ternaerer Selen-Halogenid-Komplexe des Iridiums

    Energy Technology Data Exchange (ETDEWEB)

    Stolze, Karoline

    2016-04-07

    The thesis on the synthesis and characterization of low-valence actinide phosphide tellurides and ternary selenium-halide iridium complexes includes two parts: a description of the experimental synthesis of UPTe and U2PTe2O and ThPTe and the synthesis of selenium-chloride iridium complexes and selenium-bromide iridium complexes. The characterization included X-ray diffraction and phase studies.

  12. Influence of c-axis orientation and scandium concentration on infrared active modes of magnetron sputtered Sc{sub x}Al{sub 1−x}N thin films

    Energy Technology Data Exchange (ETDEWEB)

    Mayrhofer, P. M.; Bittner, A.; Schmid, U. [Institute of Sensor and Actuator Systems, Vienna University of Technology, Floragasse 7, 1040 Vienna (Austria); Eisenmenger-Sittner, C. [Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstrasse 8, 1040 Vienna (Austria); Euchner, H. [Institute of Materials Science and Technology, Vienna University of Technology, Karlsplatz 13, 1040 Vienna (Austria)

    2013-12-16

    Doping of wurtzite aluminium nitride (AlN) with scandium (Sc) significantly enhances the piezoelectric properties of AlN. Sc{sub x}Al{sub 1−x}N thin films with different Sc concentrations (x = 0 to 0.15) were deposited by DC reactive magnetron sputtering. Infrared (IR) absorbance spectroscopy was applied to investigate the Sc concentration dependent shift of the IR active modes E{sub 1}(TO) and A{sub 1}(TO). These results are compared to ab initio simulations, being in excellent agreement with the experimental findings. In addition, IR spectroscopy is established as an economical and fast method to distinguish between thin films with a high degree of c-axis orientation and those exhibiting mixed orientations.

  13. New Intermetallic Ternary Phosphide Chalcogenide AP2-xXx (A = Zr, Hf; X = S, Se) Superconductors with PbFCl-Type Crystal Structure

    Science.gov (United States)

    Kitô, Hijiri; Yanagi, Yousuke; Ishida, Shigeyuki; Oka, Kunihiko; Gotoh, Yoshito; Fujihisa, Hiroshi; Yoshida, Yoshiyuki; Iyo, Akira; Eisaki, Hiroshi

    2014-07-01

    We have synthesized a series of intermetallic ternary phosphide chalcogenide superconductors, AP2-xXx (A = Zr, Hf; X = S, Se), using the high-pressure synthesis technique. These materials have a PbFCl-type crystal structure (space group P4/nmm) when x is greater than 0.3. The superconducting transition temperature Tc changes systematically with x, yielding dome-like phase diagrams. The maximum Tc is achieved at approximately x = 0.7, at which point the Tc is 6.3 K for ZrP2-xSex (x = 0.75), 5.5 K for HfP2-xSex (x = 0.7), 5.0 K for ZrP2-xSx (x = 0.675), and 4.6 K for Hfp2-xSx (x = 0.5). They are typical type-II superconductors and the upper and lower critical fields are estimated to be 2.92 T at 0 K and 0.021 T at 2 K for ZrP2-xSex (x = 0.75), respectively.

  14. Interaction between F2 gas with the pristine and 3C-doped(4, 4 armchair boron phosphide nanotubes: a DFT study

    Directory of Open Access Journals (Sweden)

    M Rezaei-Sameti

    2015-12-01

    Full Text Available In this research, the structure, quantum and NQR (Nuclear quadrupole resonanceparameters of F2 gas adsorption on the pristine and 3C-doped (4,4 armchair models of boron phosphide nanotubes (BPNTs have been investigated in the framework of density functional theory. For this purpose, at the first step, four models for F2 adsorption on the inner and outer surfaces of pristine and 3C-doped BPNTS are considered and then all structures are optimized by using Gaussian 03 program package. The optimized structures are used to calculate the quantum and NQR parameters. The calculated results reveal that the adsorption energy of pristine and 3C-doped models of BPNTs are exothermic and adsorption process is a physisorption process due to the weak Van der Waals interaction. The substitution of three carbons with three B atoms of nanotube decreases significantly the adsorption energies. The F2 adsorption and 3C-doping decrease the band gap, global hardness, and ionization potential of the pristine BPNTs. The calculated NQR parameters of all the models show that CQ and &etaQ values of the first layer are larger than those of the other layers.

  15. A Mechanistic Study of CO2 Reduction at the Interface of a Gallium Phosphide (GaP) Surface using Core-level Spectroscopy - Oral Presentation

    Energy Technology Data Exchange (ETDEWEB)

    Flynn, Kristen [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-19

    Carbon dioxide (CO2) emission into the atmosphere has increased tremendously through burning of fossil fuels, forestry, etc.. The increased concentration has made CO2 reductions very attractive though the reaction is considered uphill. Utilizing the sun as a potential energy source, CO2 has the possibility to undergo six electron and four proton transfers to produce methanol, a useable resource. This reaction has been shown to occur selectively in an aqueous pyridinium solution with a gallium phosphide (GaP) electrode. Though this reaction has a high faradaic efficiency, it was unclear as to what role the GaP surface played during the reaction. In this work, we aim to address the fundamental role of GaP during the catalytic conversion, by investigating the interaction between a clean GaP surface with the reactants, products, and intermediates of this reaction using X-ray photoelectron spectroscopy. We have determined a procedure to prepare atomically clean GaP and our initial CO2 adsorption studies have shown that there is evidence of chemisorption and reaction to form carbonate on the clean surface at LN2 temperatures (80K), in contrast to previous theoretical calculations. These findings will enable future studies on CO2 catalysis.

  16. Occupational phosphine gas poisoning at veterinary hospitals from dogs that ingested zinc phosphide--Michigan, Iowa, and Washington, 2006-2011.

    Science.gov (United States)

    2012-04-27

    Zinc phosphide (Zn3P2) is a readily available rodenticide that, on contact with stomach acid and water, produces phosphine (PH3), a highly toxic gas. Household pets that ingest Zn3P2 often will regurgitate, releasing PH3 into the air. Veterinary hospital staff members treating such animals can be poisoned from PH3 exposure. During 2006-2011, CDC's National Institute for Occupational Safety and Health (NIOSH) received reports of PH3 poisonings at four different veterinary hospitals: two in Michigan, one in Iowa, and one in Washington. Each of the four veterinary hospitals had treated a dog that ingested Zn3P2. Among hospital workers, eight poisoning victims were identified, all of whom experienced transient symptoms related to PH3 inhalation. All four dogs recovered fully. Exposure of veterinary staff members to PH3 can be minimized by following phosphine product precautions developed by the American Veterinary Medical Association (AVMA). Exposure of pets, pet owners, and veterinary staff members to PH3 can be minimized by proper storage, handling, and use of Zn3P2 and by using alternative methods for gopher and mole control, such as snap traps.

  17. Two scandium-biuret complexes: [Sc(C2H5N3O2)(H2O)5]Cl3 x H2O and [Sc(C2H5N3O2)4](NO3)3.

    Science.gov (United States)

    Harrison, William T A

    2008-05-01

    The scandium(III) cations in the structures of pentaaqua(biuret-kappa(2)O,O')scandium(III) trichloride monohydrate, [Sc(C(2)H(5)N(3)O(2))(H(2)O)(5)]Cl(3) x H(2)O, (I), and tetrakis(biuret-kappa(2)O,O')scandium(III) trinitrate, [Sc(C(2)H(5)N(3)O(2))(4)](NO(3))(3), (II), are found to adopt very different coordinations with the same biuret ligand. The roles of hydrogen bonding and the counter-ion in the establishment of the structures are described. In (I), the Sc(3+) cation adopts a fairly regular pentagonal bipyramidal coordination geometry arising from one O,O'-bidentate biuret molecule and five water molecules. A dense network of N-H...Cl, O-H...O and O-H...Cl hydrogen bonds help to establish the packing, resulting in dimeric associations of two cations and two water molecules. In (II), the Sc(3+) cation (site symmetry 2) adopts a slightly squashed square-antiprismatic geometry arising from four O,O'-bidentate biuret molecules. A network of N-H...O hydrogen bonds help to establish the packing, which features [010] chains of cations. One of the nitrate ions is disordered about an inversion centre. Both structures form three-dimensional hydrogen-bond networks.

  18. Phosphide oxides RE2AuP2O (RE = La, Ce, Pr, Nd): synthesis, structure, chemical bonding, magnetism, and 31P and 139La solid state NMR.

    Science.gov (United States)

    Bartsch, Timo; Wiegand, Thomas; Ren, Jinjun; Eckert, Hellmut; Johrendt, Dirk; Niehaus, Oliver; Eul, Matthias; Pöttgen, Rainer

    2013-02-18

    Polycrystalline samples of the phosphide oxides RE(2)AuP(2)O (RE = La, Ce, Pr, Nd) were obtained from mixtures of the rare earth elements, binary rare earth oxides, gold powder, and red phosphorus in sealed silica tubes. Small single crystals were grown in NaCl/KCl fluxes. The samples were studied by powder X-ray diffraction, and the structures were refined from single crystal diffractometer data: La(2)AuP(2)O type, space group C2/m, a = 1515.2(4), b = 424.63(8), c = 999.2(2) pm, β = 130.90(2)°, wR2 = 0.0410, 1050 F(2) values for Ce(2)AuP(2)O, and a = 1503.6(4), b = 422.77(8), c = 993.0(2) pm, β = 130.88(2)°, wR2 = 0.0401, 1037 F(2) values for Pr(2)AuP(2)O, and a = 1501.87(5), b = 420.85(5), c = 990.3(3) pm, β = 131.12(1)°, wR2 = 0.0944, 1143 F(2) values for Nd(2)AuP(2)O with 38 variables per refinement. The structures are composed of [RE(2)O](4+) polycationic chains of cis-edge-sharing ORE(4/2) tetrahedra and polyanionic strands [AuP(2)](4-), which contain gold in almost trigonal-planar phosphorus coordination by P(3-) and P(2)(4-) entities. The isolated phosphorus atoms and the P(2) pairs in La(2)AuP(2)O could clearly be distinguished by (31)P solid state NMR spectroscopy and assigned on the basis of a double quantum NMR technique. Also, the two crystallographically inequivalent La sites could be distinguished by static (139)La NMR in conjunction with theoretical electric field gradient calculations. Temperature-dependent magnetic susceptibility measurements show diamagnetic behavior for La(2)AuP(2)O. Ce(2)AuP(2)O and Pr(2)AuP(2)O are Curie-Weiss paramagnets with experimental magnetic moments of 2.35 and 3.48 μ(B) per rare earth atom, respectively. Their solid state (31)P MAS NMR spectra are strongly influenced by paramagnetic interactions. Ce(2)AuP(2)O orders antiferromagnetically at 13.1(5) K and shows a metamagnetic transition at 11.5 kOe. Pr(2)AuP(2)O orders ferromagnetically at 7.0 K.

  19. Bimetallic Cobalt-Based Phosphide Zeolitic Imidazolate Framework: CoP x Phase-Dependent Electrical Conductivity and Hydrogen Atom Adsorption Energy for Efficient Overall Water Splitting

    Energy Technology Data Exchange (ETDEWEB)

    Song, Junhua [School of Mechanical and Materials Engineering, Washington State University, Pullman WA 99164 USA; Zhu, Chengzhou [School of Mechanical and Materials Engineering, Washington State University, Pullman WA 99164 USA; Xu, Bo Z. [School of Mechanical and Materials Engineering, Washington State University, Pullman WA 99164 USA; Fu, Shaofang [School of Mechanical and Materials Engineering, Washington State University, Pullman WA 99164 USA; Engelhard, Mark H. [Pacific Northwest National Laboratory, Richland WA 99352 USA; Ye, Ranfeng [School of Mechanical and Materials Engineering, Washington State University, Pullman WA 99164 USA; Du, Dan [School of Mechanical and Materials Engineering, Washington State University, Pullman WA 99164 USA; Beckman, Scott P. [School of Mechanical and Materials Engineering, Washington State University, Pullman WA 99164 USA; Lin, Yuehe [School of Mechanical and Materials Engineering, Washington State University, Pullman WA 99164 USA; Pacific Northwest National Laboratory, Richland WA 99352 USA

    2016-10-25

    Cobalt-based bimetallic phosphide encapsulated in carbonized zeolitic imadazolate frameworks has been successfully synthesized and showed excellent activities toward both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Density functional theory calculation and electrochemical measurements reveal that the electrical conductivity and electrochemical activity are closely associated with the Co2P/CoP mixed phase behaviors upon Cu metal doping. This relationship is found to be the decisive factor for enhanced electrocatalytic performance. Moreover, the precise control of Cu content in Co-host lattice effectively alters the Gibbs free energy for H* adsorption, which is favorable for facilitating reaction kinetics. Impressively, an optimized performance has been achieved with mild Cu doping in Cu0.3Co2.7P/nitrogen-doped carbon (NC) which exhibits an ultralow overpotential of 0.19 V at 10 mA cm–2 and satisfying stability for OER. Cu0.3Co2.7P/NC also shows excellent HER activity, affording a current density of 10 mA cm–2 at a low overpotential of 0.22 V. In addition, a homemade electrolyzer with Cu0.3Co2.7P/NC paired electrodes shows 60% larger current density than Pt/ RuO2 couple at 1.74 V, along with negligible catalytic deactivation after 50 h operation. The manipulation of electronic structure by controlled incorporation of second metal sheds light on understanding and synthesizing bimetallic transition metal phosphides for electrolysis-based energy conversion.

  20. Reflection high-energy electron diffraction studies of indium phosphide (100) and growth on indium and indium nitride on silicon (100)

    Science.gov (United States)

    Hafez, Mohamed Abd-Elsattar

    Study of the effects of atomic hydrogen exposure on structure and morphology of semiconductor surfaces is important for fundamental properties and applications. In this dissertation, the electron yield of a hydrogen-cleaned indium phosphide (InP) surface was measured and correlated to the development of the surface morphology, which was monitored by in situ reflection high-energy electron diffraction (RHEED). Atomic hydrogen treatment produced a clean, well-ordered, and (2x4)-reconstructed InP(100) surface. The quantum efficiency, after activation to negative electron affinity, and the secondary electron emission were shown to increase with hydrogen cleaning time. RHEED patterns of low-index InP(100) surface were modified by the step structure and resulted in splitting of the specular beam at the out-of-phase diffraction condition. Quantitative RHEED showed reduction in the average terrace width and a decrease of the adatom-vacancy density with hydrogen exposure. This suggests that atomic hydrogen etching occurs preferentially at terrace edges, and thermal diffusion on the surface causes changes in the terrace edge morphology, which result in the observed decrease in the average terrace width. The results show that the decrease in the surface disorder, measured from the RHEED intensity-to-background ratio, correlated with the increased quantum efficiency. The growth of group-III metals on Si surfaces has become an attractive area of research because of its scientific importance and great potential in technological applications. In this work, the growth dynamics, structure, and morphology of indium (In) on a vicinal Si(100)-(2x1) surface by femtosecond pulsed laser deposition (fsPLD) were studied using in situ RHEED and ex situ atomic force microscopy. Indium was found to grow on Si(100) by the Stranski-Krastanove mode. At room temperature, the initial growth formed strained two-dimensional (2D) layers in the In(2x1) structure followed by growth of three

  1. Phase equilibria in the Mo-Fe-P system at 800 °C and structure of ternary phosphide (Mo(1-x)Fe(x))3P (0.10 ≤ x ≤ 0.15).

    Science.gov (United States)

    Oliynyk, Anton O; Lomnytska, Yaroslava F; Dzevenko, Mariya V; Stoyko, Stanislav S; Mar, Arthur

    2013-01-18

    Construction of the isothermal section in the metal-rich portion (ternary phases: (Mo(1-x)Fe(x))(2)P (x = 0.30-0.82) and (Mo(1-x)Fe(x))(3)P (x = 0.10-0.15). The occurrence of a Co(2)Si-type ternary phase (Mo(1-x)Fe(x))(2)P, which straddles the equiatomic composition MoFeP, is common to other ternary transition-metal phosphide systems. However, the ternary phase (Mo(1-x)Fe(x))(3)P is unusual because it is distinct from the binary phase Mo(3)P, notwithstanding their similar compositions and structures. The relationship has been clarified through single-crystal X-ray diffraction studies on Mo(3)P (α-V(3)S-type, space group I42m, a = 9.7925(11) Å, c = 4.8246(6) Å) and (Mo(0.85)Fe(0.15))(3)P (Ni(3)P-type, space group I4, a = 9.6982(8) Å, c = 4.7590(4) Å) at -100 °C. Representation in terms of nets containing fused triangles provides a pathway to transform these closely related structures through twisting. Band structure calculations support the adoption of these structure types and the site preference of Fe atoms. Electrical resistivity measurements on (Mo(0.85)Fe(0.15))(3)P reveal metallic behavior but no superconducting transition.

  2. The first-principle study of N2O gas interaction on the surface of pristine and Si-, Ga-, SiGa-doped of armchair boron phosphide nanotube using DFT method

    Directory of Open Access Journals (Sweden)

    M Rezaei-Sameti

    2016-12-01

    Full Text Available In present research,  the electrical, structural, quantum and Nuclear Magnetic Resonance (NMR parameters of interaction of N2O gas on the B and P sites of pristine, Ga-, Si- and SiGa-doped (4,4 armchair models of boron phosphide nanotubes (BPNTs are investigated by using density functional theory (DFT.  For this purpose, seven models for adsorption of N2O gas on the exterior surfaces of BPNTs have been considered and then all structures are optimized by B3LYP level of theory and 6–31G (d base set. The optimized structures are used to calculate the electrical, structural, quantum and NMR parameters. The computational results revealed that the adsorption energy of all studied models of BPNTs is negative; all processes are exothermic and favorable in thermodynamic approach. When N2O gas is adsorbed from its O atom head on the B site of nanotube, N2O gas is dissociated to O atom and N2 molecule. The adsorption energy of this process is more than those of other models and more stable than other models. In A, B and C models, the global hardness decreases significantly from original values and so the activity of nanotube increases from original state. On the other hand, the electrophilicity index (ω, electronic chemical potential (μ, electronegativity (χ and global softness (S of the A, B and C models increase significantly from original value and CSI values of the C model are larger than those of other models. The results demonstrate that the Ga-, Si- and SiGa- doped BPNTs are good candidates to adsorb N2O and make N2O gas sensor

  3. Scandium doped Strontium Titanate Ceramics: Structure, Microstructure, and Dielectric Properties

    Directory of Open Access Journals (Sweden)

    Tkach, Alexander

    2008-08-01

    Full Text Available Sc-doped strontium titanate (ST ceramics were synthesised by solid state reaction, according to the composition Sr1-1.5xScxTiO3 with x = 0-0.01. Structural properties and microstructure development was examined by XRD and SEM. The dielectric properties were evaluated as a function of the temperature and frequency in the radio frequency range. Lattice parameter, density and grain size, were found to decrease slightly with increasing Sc content. The dielectric permittivity and losses decrease also. Sc-doping has only a weak effect on the quantum paraelectric behaviour of ST and no dielectric anomaly was observed, what is probably related to the limited solubility of Sc on the Sr site of the perovskite lattice of ST.

    Se sintetizaron materiales cerámicos de titanato de estroncio dopado con escandio mediante reacción en estado sólido De acuerdo a la composición Sr1-1.5xScxTiO3 con x= 0-0.1. Las propiedades estructurales y el desarrollo microestructural se estudiaron mediante XRD y SEM. La propiedades dieléctricas se estudiaron como función de la temperatura y de la frecuencia en el rango de la frecuencias de radio. Se observó que los parámetros de red, la densidad y el tamaño del grano disminuyen ligeramente con el contenido en Sc. La permitividad dieléctrica y las perdidas también disminuyen. El dopado con Sc tiene un efecto muy ligero sobre el comportamiento paraeléctrico cuántico del titanato de estroncio y no se observó anomalías dioeléctricas , lo que está probablemente relacionado con la baja solubilidad del Sc en posiciones del Sr en la estructura tipo perovskita del titanato de estroncio.

  4. Phenoxyl radical complexes of gallium, scandium, iron and manganese.

    Science.gov (United States)

    Adam, B; Bill, E; Bothe, E; Goerdt, B; Haselhorst, G; Hildenbrand, K; Sokolowski, A; Steenken, S; Weyhermüller, T; Wieghardt, K

    1997-02-01

    The hexadentate macrocyclic ligands 1,4,7-tris(3,5-dimethyl-2-hydroxybenzyl)-1,4,7-triazacyclononane (L CH 3H3 ), 1,4,7-tris(3,5-di-tert-butyl-2-hydroxybenzyl)-1,4,7-triazacyclononane (L(Bu) H3 ) and 1,4,7-tris(3-tert-butyl-5-methoxy-2-hydroxybenzyl)-1,4,7-triazacyclononane (L OCH 3-H3 ) form very stable octahedral neutral complexes LM(III) with trivalent (or tetravalent) metal ions (Ga(III) , Sc(III) , Fe(III) , Mn(III) , Mn(IV) ). The following complexes have been synthesized: [L(Bu) M], where M = Ga (1), Sc (2), Fe (3); [L(Bu) Mn(IV) ]PF6 (4'); [L OCH 3M], where M = Ga (1 a), Sc (2 a), Fe (3 a); [L OCH 3Mn(IV) ]PF6 (4 a'); [L CH 3M], where M = Sc (2 b), Fe (3 b), Mn(III) (4 b); [L CH 3Mn(IV) ]2 (ClO4 )3 (H3 O)(H2 O)3 (4 b'). An electrochemical study has shown that complexes 1, 2, 3, 1 a, 2 a and 3 a each display three reversible, ligand-centred, one-electron oxidation steps. The salts [L OCH 3Fe(III) ]ClO4 and [L OCH 3Ga(III) ]ClO4 , have been isolated as stable crystalline materials. Electronic and EPR spectra prove that these oxidations produce species containing one, two or three coordinated phenoxyl radicals. The Mössbauer spectra of 3 a and [3 a](+) show conclusively that both compounds contain high-spin iron(III) central ions. Temperature-dependent magnetic susceptibility measurements reveal that 3 a has an S = 5/2 and [3a](+) an S = 2 ground state. The latter is attained through intramolecular antiferromagnetic exchange coupling between a high-spin iron(III) (S1 = 5/2) and a phenoxyl radical (S2 = 1/2) (H = - 2JS1 S2 ; J = - 80 cm(-1) ). The manganese complexes undergo metal- and ligand-centred redox processes, which were elucidated by spectroelectrochemistry; a phenoxyl radical Mn(IV) complex [Mn(IV) L OCH 3](2+) is accessible. Copyright © 1997 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Atomic layer deposition of scandium-based oxides

    Energy Technology Data Exchange (ETDEWEB)

    Nyns, Laura; Lisoni, Judit G.; Bosch, Geert van den; Elshocht, Sven van; Houdt, Jan van [IMEC, Leuven (Belgium)

    2014-02-15

    Gd{sub x}Sc{sub 2-x}O{sub 3} and Al{sub x}Sc{sub 2-x}O{sub 3} have been investigated as potential high-k intergate dielectric (IGD) in planar NAND flash technology, such as hybrid floating gate (HFG). We have examined the atomic layer deposition (ALD) of Sc{sub 2}O{sub 3}, Gd{sub x}Sc{sub 2-x}O{sub 3}, and Al{sub x}Sc{sub 2-x}O{sub 3} on Si using Sc(MeCp){sub 3}, Gd({sup i}PrCp){sub 3}, TMA, and H{sub 2}O as precursors. The composition of Gd{sub x}Sc{sub 2-x}O{sub 3} and Al{sub x}Sc{sub 2-x}O{sub 3} ranged from 4% to 76% Gd and from 7% to 66% Al, respectively. All compositions show linear growth behavior. While pure Sc{sub 2}O{sub 3} is crystalline as-deposited, the layer becomes amorphous once ∝20% of Al is added. The (222) reflection of the cubic phase is also seen for Gd{sub x}Sc{sub 2-x}O{sub 3} with less than 9% Gd. The bandgap of as-deposited Gd{sub x}Sc{sub 2-x}O{sub 3} decreases with increasing Gd content while the opposite trend is observed for Al{sub x}Sc{sub 2-x}O{sub 3}. A k-value of ∝21 can be obtained for Gd{sub x}Sc{sub 2-x}O{sub 3} with approximately 26-52% Gd, irrespective of the Gd content. For Al{sub x}Sc{sub 2-x}O{sub 3} on the other hand, a maximum k-value of ∝19 is achieved with ∝48% Al. Although the k-value of Al{sub x}Sc{sub 2-x}O{sub 3} is lower than that of Gd{sub x}Sc{sub 2-x}O{sub 3}, its large breakdown field makes this material more suitable for HFG flash applications. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Spark plasma sintering of aluminum powders prealloyed with scandium additions

    Energy Technology Data Exchange (ETDEWEB)

    Cooke, R.W.; Kraus, N.P.; Bishop, D.P., E-mail: Paul.Bishop@dal.ca

    2016-03-07

    The objective of this research was to commence work on the spark plasma sintering (SPS) of Al–Sc alloys in an effort to develop fundamental data in this area. In this precursory study, a series of binary systems containing 0.1 to 0.4 wt% Sc were processed in laboratory and industrial-scale equipment. Data revealed that all powders were responsive to SPS in both scenarios and that sintering temperature was a variable of critical importance. Hardness of as-sintered products scaled directly with Sc concentration but varied inversely with SPS temperature owing to in-situ aging of the raw powders. Hardness losses could be recovered through a post-SPS heat treatment into the T6 condition. Industrially processed slugs of Al-0.4Sc-T6 exhibited full densification and offered the highest hardness (786+/−8 MPa). This was accompanied by a nominal tensile yield strength of 197 MPa, UTS of 226 MPa and tensile ductility of 11%.

  7. Tin etching from metallic and oxidized scandium thin films

    NARCIS (Netherlands)

    Pachecka, Malgorzata; Lee, Christopher James; Sturm, J.M.; Bijkerk, Frederik

    The role of oxide on Sn adhesion to Sc surfaces was studied with in-situ ellipsometry, X-ray photoelectron spectroscopy and secondary electron microscopy. Sn etching with hydrogen radicals was performed on metallic Sc, metallic Sc with a native oxide, and a fully oxidized Sc layer. The results show

  8. The structural and magnetic properties of holmium/scandium superlattices

    DEFF Research Database (Denmark)

    Bryn-Jacobsen, C.; Cowley, R.A.; McMorrow, D.F.

    1997-01-01

    The properties of Ho/Sc superlattices grown by molecular beam epitaxy (MBE) have been investigated using X-ray and neutron diffraction techniques. Structural studies reveal the novel existence of more than one a lattice parameter. Examining the magnetic properties, it is found that the Ho 4f...

  9. Electrostatically driven resonance energy transfer in “cationic” biocompatible indium phosphide quantum dots† †Electronic supplementary information (ESI) available: Detailed experimental methods, the synthesis and characterization of QDs, bioimaging, stability studies, control experiments, and the calculation of various parameters involved in the resonance energy transfer process etc. See DOI: 10.1039/c7sc00592j Click here for additional data file.

    Science.gov (United States)

    Devatha, Gayathri; Roy, Soumendu; Rao, Anish; Mallick, Abhik; Basu, Sudipta

    2017-01-01

    Indium Phosphide Quantum Dots (InP QDs) have emerged as an alternative to toxic metal ion based QDs in nanobiotechnology. The ability to generate cationic surface charge, without compromising stability and biocompatibility, is essential in realizing the full potential of InP QDs in biological applications. We have addressed this challenge by developing a place exchange protocol for the preparation of cationic InP/ZnS QDs. The quaternary ammonium group provides the much required permanent positive charge and stability to InP/ZnS QDs in biofluids. The two important properties of QDs, namely bioimaging and light induced resonance energy transfer, are successfully demonstrated in cationic InP/ZnS QDs. The low cytotoxicity and stable photoluminescence of cationic InP/ZnS QDs inside cells make them ideal candidates as optical probes for cellular imaging. An efficient resonance energy transfer (E ∼ 60%) is observed, under physiological conditions, between the cationic InP/ZnS QD donor and anionic dye acceptor. A large bimolecular quenching constant along with a linear Stern–Volmer plot confirms the formation of a strong ground state complex between the cationic InP/ZnS QDs and the anionic dye. Control experiments prove the role of electrostatic attraction in driving the light induced interactions, which can rightfully form the basis for future nano-bio studies between cationic InP/ZnS QDs and anionic biomolecules. PMID:28626557

  10. Electron microscopy imaging of proteins on gallium phosphide semiconductor nanowires

    Science.gov (United States)

    Hjort, Martin; Bauer, Mikael; Gunnarsson, Stefan; Mårsell, Erik; Zakharov, Alexei A.; Karlsson, Gunnel; Sanfins, Elodie; Prinz, Christelle N.; Wallenberg, Reine; Cedervall, Tommy; Mikkelsen, Anders

    2016-02-01

    We have imaged GaP nanowires (NWs) incubated with human laminin, serum albumin (HSA), and blood plasma using both cryo-transmission electron microscopy and synchrotron based X-ray photoemission electron microscopy. This extensive imaging methodology simultaneously reveals structural, chemical and morphological details of individual nanowires and the adsorbed proteins. We found that the proteins bind to NWs, forming coronas with thicknesses close to the proteins' hydrodynamic diameters. We could directly image how laminin is extending from the NWs, maximizing the number of proteins bound to the NWs. NWs incubated with both laminin and HSA show protein coronas with a similar appearance to NWs incubated with laminin alone, indicating that the presence of HSA does not affect the laminin conformation on the NWs. In blood plasma, an intermediate sized corona around the NWs indicates a corona with a mixture of plasma proteins. The ability to directly visualize proteins on nanostructures in situ holds great promise for assessing the conformation and thickness of the protein corona, which is key to understanding and predicting the properties of engineered nanomaterials in a biological environment.We have imaged GaP nanowires (NWs) incubated with human laminin, serum albumin (HSA), and blood plasma using both cryo-transmission electron microscopy and synchrotron based X-ray photoemission electron microscopy. This extensive imaging methodology simultaneously reveals structural, chemical and morphological details of individual nanowires and the adsorbed proteins. We found that the proteins bind to NWs, forming coronas with thicknesses close to the proteins' hydrodynamic diameters. We could directly image how laminin is extending from the NWs, maximizing the number of proteins bound to the NWs. NWs incubated with both laminin and HSA show protein coronas with a similar appearance to NWs incubated with laminin alone, indicating that the presence of HSA does not affect the laminin conformation on the NWs. In blood plasma, an intermediate sized corona around the NWs indicates a corona with a mixture of plasma proteins. The ability to directly visualize proteins on nanostructures in situ holds great promise for assessing the conformation and thickness of the protein corona, which is key to understanding and predicting the properties of engineered nanomaterials in a biological environment. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08888g

  11. Nanoimprinted DWDM laser arrays on indium phosphide substrates

    DEFF Research Database (Denmark)

    Smistrup, Kristian; Nørregaard, Jesper; Mironov, Andrej

    2014-01-01

    Dense wavelength division multiplexing lasers play a major role in today's long-haul broadband communication. Typical distributed feedback laser cavities consist of long half-pitch gratings in InGaAsP on InP substrates with grating periods of around 240 nm. The lasers include a quarter wavelength...

  12. X-ray photoelectron spectroscopy of FeP phosphide

    Energy Technology Data Exchange (ETDEWEB)

    Teterin, Yu. A.; Sobolev, A. V., E-mail: salex12@rambler.ru, E-mail: alex@radio.chem.msu.ru; Presnyakov, I. A.; Maslakov, K. I. [Moscow State University (Russian Federation); Teterin, A. Yu. [National Research Center “Kurchatov Institute,” (Russian Federation); Morozov, I. V.; Chernyavskii, I. O. [Moscow State University (Russian Federation); Ivanov, K. E. [National Research Center “Kurchatov Institute,” (Russian Federation); Shevel’kov, A. V. [Moscow State University (Russian Federation)

    2017-02-15

    The structure of the outer and inner electron spectra of iron (2p, 3p, 3s, and 3d) and phosphorus (3s and 3p) atoms in FeP monophosphide is studied in detail by the X-ray photoelectron spectroscopy (XPS) method. On the basis of the analysis of the binding energy of electrons, as well as the parameters characterizing the structure of experimental spectra, a conclusion is made that Fe{sup 3+} (d{sup 5}) cations in FeP are stabilized in a state with intermediate value of the total spin (IS, S = 3/2). The range of values of intra-atomic parameters (10Dq, J{sub H}) is established in which the consideration of the high degree of covalence of Fe–P bonds may lead to the stabilization of (FeP{sub 6}){sup 15–} clusters in the IS state.

  13. Porous gallium phosphide: Challenging material for nonlinear-optical applications

    Energy Technology Data Exchange (ETDEWEB)

    Melnikov, V.A.; Golovan, L.A.; Konorov, S.O.; Fedotov, A.B.; Zheltikov, A.M.; Timoshenko, V. Yu.; Kashkarov, P.K. [Physics Department, M.V. Lomonosov Moscow State University, 119992 Moscow (Russian Federation); Petrov, G.I.; Li, L.; Yakovlev, V.V. [Physics Department, University of Wisconsin-Milwaukee, 53211 Milwaukee, WI (United States); Gavrilov, S.A.

    2005-06-01

    Electrochemically produced porous GaP layers demonstrate strong non-Rayleigh light scattering in visible range. Moreover, (110) porous GaP layers exhibit in-plane birefringence. Both properties offer much promises for enhanced nonlinear-optical processes. We report experimental studies of spectral and orientation dependences of the second-harmonic generation in (110) and (111) porous GaP layers. An order of magnitude increase of the second-harmonic intensity was found in the strongly scattering porous GaP layers in comparison with monocrystalline GaP. The spectral dependence of the second-harmonic intensity was discussed in terms of the phase matching and light localization phenomena. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Alternative catalytic materials: carbides, nitrides, phosphides and amorphous boron alloys.

    Science.gov (United States)

    Alexander, Anne-Marie; Hargreaves, Justin S J

    2010-11-01

    Catalysts generated by the addition of carbon, nitrogen or phosphorus to transition metals have interesting properties and potential applications. The addition of carbon, nitrogen or phosphorus can lead to substantial modification of the catalytic efficacy of the parent metal and some carbides and nitrides are claimed to be comparable to noble metals in their behaviour. Amorphous boron transition metal alloys are also a class of interesting catalyst, although their structures and phase composition are more difficult to define. In this critical review, the preparation of these catalysts is described and brief details of their application given. To date, attention has largely centred upon the application of these materials as alternatives for existing catalysts. However, novel approaches towards their utilisation can be envisaged. For example, the extent to which it is possible to utilise the "activated" carbon and nitrogen species within the host lattices of carbides and nitrides, respectively, as a reactant remains largely unexplored (195 references).

  15. Role of Impurities in Faraday Rotation in Indium Phosphide

    Science.gov (United States)

    Syed, Maarij; Siahmakoun, Azad

    2002-03-01

    We report on the investigation of Faraday rotation (FR) in photorefractive (PR) indium phophide (InP:Fe) for different samples, conducted at several different wavelengths at room temperature. Appreciable FR, yielding Verdet constant values at 980, 1064, 1300, and 1550 nm at room temperature, has been observed. The choice of these wavelengths was guided by two important considerations. Firstly, these are wavelengths of interest for communication purposes and secondly FR in more conventional magnetic and iron doped materials has shown a dependence on the band gap. The role of excitation energy in FR has yielded important information regarding the differences that exist between FR models for conventional materials and photorefractive InP:Fe. We have also investigated the role of dopant concentration, and dopant species. A preliminary discussion of these factors will be presented. In addition, we will also show some conclusions regarding the intensity of the incident beam and its initial polarization state. Verdet constant values were found to be the highest for the incident beam wavelength of 980 nm. At 980 nm and applied magnetic field of 1.5 ± 0.05 tela, polarization rotation of 45 ± 1.0 degrees has been observed. This value of 45o is a benchmark for optical isolator applications. In this study we will provide important clues about the magnetic properties of semi-insulating PR InP:Fe crystal.

  16. Production of scandium-44m and scandium-44g with deuterons on calcium-44: cross section measurements and production yield calculations

    Science.gov (United States)

    Duchemin, C.; Guertin, A.; Haddad, F.; Michel, N.; Métivier, V.

    2015-09-01

    HIGHLIGHTS • Production of Sc-44m, Sc-44g and contaminants. • Experimental values determined using the stacked-foil technique. • Thick-Target production Yield (TTY) calculations. • Comparison with the TALYS code version 1.6. Among the large number of radionuclides of medical interest, Sc-44 is promising for PET imaging. Either the ground-state Sc-44g or the metastable-state Sc-44m can be used for such applications, depending on the molecule used as vector. This study compares the production rates of both Sc-44 states, when protons or deuterons are used as projectiles on an enriched Calcium-44 target. This work presents the first set of data for the deuteron route. The results are compared with the TALYS code. The Thick-Target production Yields of Sc-44m and Sc-44g are calculated and compared with those for the proton route for three different scenarios: the production of Sc-44g for conventional PET imaging, its production for the new 3 γ imaging technique developed at the SUBATECH laboratory and the production of a Sc-44m/Sc-44g in vivo generator for antibody labelling.

  17. Structures and H2 adsorption properties of porous scandium metal-organic frameworks.

    Science.gov (United States)

    Ibarra, Ilich A; Lin, Xiang; Yang, Sihai; Blake, Alexander J; Walker, Gavin S; Barnett, Sarah A; Allan, David R; Champness, Neil R; Hubberstey, Peter; Schröder, Martin

    2010-12-10

    Two new three-dimensional Sc(III) metal-organic frameworks {[Sc(3)O(L(1))(3)(H(2)O)(3)]·Cl(0.5)(OH)(0.5)(DMF)(4)(H(2)O)(3)}(∞) (1) (H(2)L(1)=1,4-benzene-dicarboxylic acid) and {[Sc(3)O(L(2))(2)(H(2)O)(3)](OH)(H(2)O)(5)(DMF)}(∞) (2) (H(3)L(2)=1,3,5-tris(4-carboxyphenyl)benzene) have been synthesised and characterised. The structures of both 1 and 2 incorporate the trinuclear trigonal planar [Sc(3)(O)(O(2)CR)(6)] building block featuring three Sc(III) centres joined by a central μ(3)-O(2-) donor. Each Sc(III) centre is further bound by four oxygen donors from four different bridging carboxylate anions, and a molecule of water located trans to the μ(3)-O(2-) donor completes the six coordination at the metal centre. Frameworks 1 and 2 show high thermal stability with retention of crystallinity up to 350 °C. The desolvated materials 1a and 2a, in which the solvent has been removed from the pores but with water or hydroxide remaining coordinated to Sc(III), show BET surface areas based upon N(2) uptake of 634 and 1233 m(2) g(-1), respectively, and pore volumes calculated from the maximum N(2) adsorption of 0.25 cm(3) g(-1) and 0.62 cm(3) g(-1), respectively. At 20 bar and 78 K, the H(2) isotherms for desolvated 1a and 2a confirm 2.48 and 1.99 wt% total H(2) uptake, respectively. The isosteric heats of adsorption were estimated to be 5.25 and 2.59 kJ mol(-1) at zero surface coverage for 1a and 2a, respectively. Treatment of 2 with acetone followed by thermal desolvation in vacuo generated free metal coordination sites in a new material 2b. Framework 2b shows an enhanced BET surface area of 1511 m(2) g(-1) and a pore volume of 0.76 cm(3) g(-1), with improved H(2) uptake capacity and a higher heat of H(2) adsorption. At 20 bar, H(2) capacity increases from 1.99 wt% in 2a to 2.64 wt% for 2b, and the H(2) adsorption enthalpy rises markedly from 2.59 to 6.90 kJ mol(-1).

  18. Scandium and Chromium in the Strontium Filament in the Homunculus of eta Carinae

    Science.gov (United States)

    Gull, T.R.; Melendez, M.; Baustista, M.A.; Ballance, C.; Hartman, H.; Lodders, K.; Martinez, M.

    2008-01-01

    We continue a systematic study of chemical abundances of the Strontium Filament found in the ejecta of eta Carinae. To this end we interpret the emission spectrum of Sc II and Cr II using multilevel non-LTE models of these systems. Since the atomic data for these ions was previously unavailable, we carry out ab initio calculations of radiative transition rates and electron impact excitation rate coefficients. The observed spectrum is emitted from a mostly neutral region with electron density of the order of 10(exp 7) cm (exp -3) and a temperature between 6000 and 7000 K. These conditions are consistent with our previous diagnostics from [Ni II], [Ti II], amd [Sr II]. The observed spectrum indicates an abundance of Sc relative Ni that more than 40 times the solar values, while the Cr/Ni abundance ratio is roughly solar. Various scenarios of depletion and dust destruction are suggested to explain such abnormal abundances.

  19. Lithium scandium phosphate-based electrolytes for solid state lithium rechargeable microbatteries

    Energy Technology Data Exchange (ETDEWEB)

    Amatucci, G.G. (Dept. of Ceramics, Rutgers Univ., Piscataway, NJ (United States)); Safari, A. (Dept. of Ceramics, Rutgers Univ., Piscataway, NJ (United States)); Shokoohi, F.K. (Bellcore, Red Bank, NJ (United States)); Wilkens, B.J. (Bellcore, Red Bank, NJ (United States))

    1993-04-01

    Li[sub 3]Sc[sub 2](PO[sub 4])[sub 3] is a promising candidate for use as an electrolyte in solid state lithium rechargeable microbatteries due to its stability in air, ease of preparation, and resistance to dielectric breakdown. The room temperature ionic conductivity was optimized resulting in an increase of over two orders of magnitude to 3 x 10[sup -6] S/cm. The formation of Li[sub 3](Sc[sub 2-x]M[sub x])(PO[sub 4])[sub 3], where M=Al[sup 3+] of Y[sup 3+], resulted in the decrease of porosity, greater sinterability, and considerable enhancement of the ionic conductivity. Yttrium substitutions enhanced the conductivity slightly while aluminum increased the room temperature ionic conductivity to 1.5 x 10[sup -5] S/cm for x=0.4. Preliminary electron beam evaporation of Li[sub 3]Sc[sub 2](PO[sub 4])[sub 3] yielded amorphous thin films with ionic conductivity as high as 5 x 10[sup -5] S/cm and a composition of Li[sub 4.8]Sc[sub 1.4](PO[sub 4])[sub 3]. (orig.)

  20. The Low-Lying Electronic States of Scandium Monocarbide, ScC

    Science.gov (United States)

    Chen, Chiao-Wei; Merer, Anthony; Hsu, Yen-Chu

    2017-06-01

    Extensive wavelength-resolved fluorescence studies have been carried out for the electronic bands of ScC and Sc{}^{13}C lying in the range 14000 - 16000 cm^{-1}. Taken together with detailed rotational analyses of these bands, these studies have clarified the natures of the low-lying electronic states. The ground state is an Ω = 3/2 state, with a vibrational frequency of 648 cm^{-1}, and the first excited electronic state is an Ω = 5/2 state, with a frequency of 712 cm^{-1}, lying 155.54 cm^{-1} higher. These states are assigned as the lowest spin-orbit components of X^2Π_i and a^4Π_i, respectively. The quartet nature of the a state is confirmed by the observation of the ^4Π_{3/2} component, 18.71 cm^{-1} above the ^4Π_{5/2} component. The strongest bands in the region studied are two ^4Δ_{7/2} - ^4Π_{5/2} transitions, where the upper states lie 14355 and 15445 cm^{-1} above X^2Π_{3/2}. Extensive doublet-quartet mixing occurs, which results in some complicated emission patterns. The energy order, a^4Π above X^2Π, is consistent with the ab initio calculations of Kalemos et al., but differs from that found by Simard et al in the isoelectronic YC molecule. A. Kalemos, A. Mavridis and J.F. Harrison, J. Phys. Chem. A155, 755 (2001). B. Simard, P.A. Hackett and W.J. Balfour, Chem. Phys. Lett., 230, 103 (1994).

  1. Effect of scandium on structure and hardening of Al–Ca eutectic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Belov, N.A., E-mail: nikolay-belov@yandex.ru [National Research and Technological University “MISIS”, 4, Leninsky pr., Moscow 119049 (Russian Federation); Naumova, E.A. [Bauman Moscow State Technical University, 5, 2 ul. Baumanskaya, Moscow, 105005 (Russian Federation); Alabin, A.N. [National Research and Technological University “MISIS”, 4, Leninsky pr., Moscow 119049 (Russian Federation); UC RUSAL, 13/1, Nikoloyamskaya st., Moscow, 109240 (Russian Federation); Matveeva, I.A. [UC RUSAL, 13/1, Nikoloyamskaya st., Moscow, 109240 (Russian Federation)

    2015-10-15

    The phase composition, structure and hardening of alloys in the aluminium corner of the Al–Ca–Sc system were studied in the range up to 10% Ca and up to 1% S≿. The experimental study (optical, scanning and transmission electron microscopy with electron-microprobe analysis, differential thermal analysis and hardness measurements) was combined with Thermo-Calc software simulation for the optimization of the alloy composition. It was shown that only phases of the binary systems (Al{sub 4}Ca and Al{sub 3}Sc) might be in equilibrium with the aluminium solid solution. It was shown that the (Al) + Al{sub 4}Ca eutectic had a much finer structure as compared with the Al–Si eutectic, which suggests a possibility of reaching higher mechanical properties as compared to commercial alloys of the A356 type. The influence of the annealing temperature within the range up to 600 °C on the structure and hardness of the Al–Ca–Sc experimental alloys was studied. It was determined that the maximum hardening corresponded to the annealing at 300 °C, which was due to the precipitation of Al{sub 3}Sc nanoparticles with their further coarsening. With an example of an Al-7.6% Ca-0.3% Sc model experimental alloy, a principal possibility of manufacturing aluminium casting alloys based on the (Al) + Al{sub 4}Ca eutectic was demonstrated. Unlike commercial alloys of the A356 type, the model alloy does not require quenching, as hardening particles are formed in the course of annealing of casting. - Highlights: • Al–Ca–Sc phase diagram in aluminum corner. • Formation of Al{sub 3}Sc nanoparticles in eutectic (Al) + Al{sub 4}Ca during heating at 300–450 °C. • Hardening and thermal stability of proposed (Al–Ca–Sc) and commercial (Al–Si–Mg, 356 type) eutectic alloys.

  2. Conditioning of red mud for subsequent titanium and scandium recovery. A conceptual design study

    Energy Technology Data Exchange (ETDEWEB)

    Alkan, G.; Xakalashe, B.; Kaussen, F.; Friedrich, Bernd [RWTH Aachen Univ. (Germany). IME Inst. of Process Metallurgy and Metal Recycling; Yagmurlu, B. [RWTH Aachen Univ. (Germany). IME Inst. of Process Metallurgy and Metal Recycling; MEAB Chemie Technik GmbH, Aachen (Germany)

    2017-03-15

    Leaching experiments were undertaken on red mud materials (red mud and red mud slag). The red mud slag was produced via the carbothermic reduction of red mud at high temperatures (T > 1500 C) via SAF treatment. Furthermore, iron was recovered in the smelting step to the metal phase. Ti and Sc were successfully recovered from the red mud materials by hydrometallurgical treatment. For both critical metals, it was found that sulfuric acid was the best mineral acid among others. Since direct red mud leaching had some shortcomings, a route designed to overcome them is proposed. For optimal Ti and Sc recovery from red mud a promising process flowsheet combining pyrometallurgical and hydrometallurgical treatment is proposed as follows: pyrometallurgical processing (fluxed smelting to produce calcium oxide based slag phases and controlled cooling for crystalline and glassy slags), leaching for maximized Ti- and Sc extraction and followed by a multistage precipitation (for metal recovery and solution purification). Initial trial results showed that the proposed process is promising.

  3. Supercritical fluid chemical deposition of Pd nanoparticles on magnesium–scandium alloy for hydrogen storage

    Energy Technology Data Exchange (ETDEWEB)

    Couillaud, Samuel; Kirikova, Marina [CNRS, ICMCB, UPR 9048, F-33600 Pessac (France); Univ. Bordeaux, ICMCB, UPR 9048, F-33600 Pessac (France); Zaïdi, Warda; Bonnet, Jean-Pierre [LRCS, UMR CNRS 6007, 33 rue Saint-Leu, 80039-Amiens (France); Marre, Samuel; Aymonier, Cyril [CNRS, ICMCB, UPR 9048, F-33600 Pessac (France); Univ. Bordeaux, ICMCB, UPR 9048, F-33600 Pessac (France); Zhang, Junxian; Cuevas, Fermin; Latroche, Michel [ICMPE, CNRS-UPEC, UMR 7182, 2-8 rue Henri Dunant, 94320-Thiais (France); Aymard, Luc [LRCS, UMR CNRS 6007, 33 rue Saint-Leu, 80039-Amiens (France); Bobet, Jean-Louis, E-mail: bobet@icmcb-bordeaux.cnrs.fr [CNRS, ICMCB, UPR 9048, F-33600 Pessac (France); Univ. Bordeaux, ICMCB, UPR 9048, F-33600 Pessac (France)

    2013-10-15

    Highlights: •Nanoparticles of Pd were deposed on the binary compound Mg{sub 0.65}Sc{sub 0.35} using the Supercritical Fluid Chemical Deposition (SFCD) method. •Numerous parameters were tested and optimized in order to obtain a homogeneous deposition. •At the first step, Pd@Mg0.65Sc0.35 decomposes into ScH{sub 2} and MgH{sub 2} under hydrogen pressure (1 MPa) at 330 °C. •The mixture, after decomposition absorbs hydrogen reversibly on Mg/MgH{sub 2} couple with good kinetics. -- Abstract: The deposition of Pd nanoparticles on the binary compound Mg{sub 0.65}Sc{sub 0.35} using the Supercritical Fluid Chemical Deposition (SFCD) method was performed. There, the SFCD operating parameters (co-solvent, temperature, CO{sub 2} and hydrogen pressure, reaction time) have been optimized to obtain homogeneous deposition of Pd nanoparticles (around 10 nm). The hydrogenation properties of the optimized Pd@Mg{sub 0.65}Sc{sub 0.35} material were determined and compared to those of Mg{sub 0.65}Sc{sub 0.35}Pd{sub 0.024}. The latter compound forms at 300 °C and 1 MPa of H{sub 2} a hydride that crystallizes in the fluorite structure, absorbs reversibly 1.5 wt.% hydrogen and exhibits fast kinetics. In contrast, Pd@Mg{sub 0.65}Sc{sub 0.35} compound decomposes into ScH{sub 2} and MgH{sub 2} during hydrogen absorption under the same conditions. However, reversible sorption reaches 3.3 wt.% of hydrogen while keeping good kinetics. The possible roles of Pd on the hydrogen-induced alloy decomposition are discussed.

  4. Geochemistry of oceanic igneous rocks - Ridges, islands, and arcs - With emphasis on manganese, scandium, and vanadium

    Science.gov (United States)

    Doe, B.R.

    1997-01-01

    A database on a number of elements in oceanic volcanic rocks is presented, including the principal major-element oxides - SiO2, TiO2, Al2O3, Fe2O3(T), MnO, MgO, CaO, Na2O, K2O, and P2O5 (where T refers to total iron) - and the trace elements - Ba, Ce, Cr, Cu, Ni, Sc, Sr, V, Pb (mainly by isotope dilution), Yb, Zn, and Zr. Interpretations are given for transition metals, with emphasis on Mn, Sc, and V, in order to determine the concentration of the elements in primitive melts and assess their trends in magmatic differentiation. Transition metals are not enriched in plagioclase, so all are incompatible with pure plagioclase removal - that is, they become enriched in the melt. Both Cr and Ni are known to be highly compatible with olivine separation - i.e., they are depleted in the melt early in differentiation. Also, Sc is compatible with clinopyroxene (Cpx) removal from the melt and is depleted by separation of Cpx. Copper does not fit well in any of the principal silicates, but Cu, like Ni, is greatly enriched in sulfides that may remain in the source or separate from the magma. Decreasing Ni abundances and increasing Cu contents during differentiation are a sign of olivine separation. In the analysis presented herein, V - in the absence of Cpx separation - is found to behave remarkably like the moderately incompatible element Zn, and these two elements add to the list of element pairs of similar incompatibility whose ratios are insensitive to differentiation and to submarine weathering as well. Both are enhanced in titanomagnetite, so both would he compatible during titanomagnetite separation. When Cpx separates, however, V becomes compatible like Sc, but Zn remains incompatible. Thus, decreasing V (and Sc) contents and increasing Zn contents during differentiation are a sign of Cpx separation. Manganese often behaves much like Zn and therefore is moderately incompatible, but Mn is less compatible than Zn and V in titanomagnetite. Thus, decreasing Zn and V with increasing Mn is an indication of titanomagnetite removal. Dual compatible and incompatible trends with differentiation are found chiefly for Cu, Sc, and Sr. Distinguishing mid-ocean ridge basalts (MORB), oceanic-island volcanic rocks (OIV), and island-arc volcanic rocks (IAV) may be accomplished by plots of Ce/Yb versus Ba/Ce, where OIV plot to higher values of Ce/Yb than do MORB, and IAV data plot to higher values of Ba/Ce than do those of MORB. These ratios do not seem to be significantly affected by submarine weathering.

  5. Heteroepitaxial growth and electric properties of (110)-oriented scandium nitride films

    Science.gov (United States)

    Ohgaki, Takeshi; Sakaguchi, Isao; Ohashi, Naoki; Haneda, Hajime

    2017-10-01

    ScN films were grown on MgO(110) substrates and α-Al2O3(10 1 bar 0) substrates by a molecular beam epitaxy method, and their crystalline orientation, crystallinity, and electric properties were examined. (110)-oriented ScN films were epitaxially grown on MgO(110) substrates with the same crystal orientations, and ScN films with an orientation relationship (110)ScN || (10 1 bar 0)α-Al2O3 and [001]ScN || [ 1 2 bar 10 ]α-Al2O3 were epitaxially grown on α-Al2O3(10 1 bar 0) substrates. Remarkably, electric-resistivity anisotropy was observed for ScN films grown on MgO(110) substrates, and the anisotropy depended on the growth temperature. The carrier concentration and Hall mobility of the ScN films grown on α-Al2O3(10 1 bar 0) substrates ranged from 1019-1021 cm-3 and 10-150 cm2 V-1 s-1, respectively. The crystallinity, crystalline-orientation anisotropy, and electric properties of the films were strongly affected by growth conditions. For the growth of ScN films with high mobility on α-Al2O3(10 1 bar 0) substrates, a high temperature and an appropriate ratio of source materials were necessary.

  6. Experimental partitioning of rare earth elements and scandium among armalcolite, ilmenite, olivine and mare basalt liquid

    Science.gov (United States)

    Irving, A. J.; Merrill, R. B.; Singleton, D. E.

    1978-01-01

    An experimental study was carried out to measure partition coefficients for two rare-earth elements (Sm and Tm) and Sc among armalcolite, ilmenite, olivine and liquid coexisting in a system modeled on high-Ti mare basalt 74275. This 'primitive' sample was chosen for study because its major and trace element chemistry as well as its equilibrium phase relations at atmospheric pressure are known from previous studies. Beta-track analytical techniques were used so that partition coefficients could be measured in an environment whose bulk trace element composition is similar to that of the natural basalt. Partition coefficients for Cr and Mn were determined in the same experiments by microprobe analysis. The only equilibrium partial melting model appears to be one in which ilmenite is initially present in the source region but is consumed by melting before segregation of the high-Ti mare basalt liquid from the residue.

  7. Effects of erbium‑and chromium‑doped yttrium scandium gallium ...

    African Journals Online (AJOL)

    Results: According to the SEM images, the Er, Cr: YSGG laser causes irradiation markings that appear as demineralized surfaces on tooth samples. The Er, Cr: YSGG laser also caused deep defects on composite, compomer, and RMGIC surfaces because of its high power, and the ablation was deeper for these samples.

  8. Structural and magnetic properties of holmium-scandium alloys and superlattices

    DEFF Research Database (Denmark)

    Bryn-Jacobsen, C.; Cowley, R.A.; McMorrow, D.F.

    1997-01-01

    in the alloys form a basal-plane helix at all temperatures, with distortions of the helical arrangement for samples with the highest Ho concentrations. The dependences of the Neel temperature, T-N and the helical wave vector upon both temperature and concentration are compared with those of other alloy systems......The properties of Ho-Sc alloys and superlattices grown by molecular-beam epitaxy have been investigated using x-ray and neutron-diffraction techniques. Structural studies reveal that the alloy samples have different a lattice parameters for the Sc-seed layer and the Ho:Sc alloy grown on top....... It is found that a good description of the dependence of T-N upon concentration is given by a virtual-crystal model where the peak in the conduction-electron susceptibility varies linearly between that of the pure constituents. In the superlattices, the moments also form a basal-plane helix at T...

  9. Cage-Core Interactions in Fullerenes Enclosing Metal Clusters with Multiple Scandium and Yttrium Atoms.

    Science.gov (United States)

    Dan, Liu; Hagelberg, Frank

    2007-03-01

    Pronounced stability has been reported for metallofullerenes of the form NSc3@CN (N = 68, 78) /1/. In response of these and related findings, Density Functional Theory studies have been performed on the relation between cage-core interactions and the geometry as well as stability of endofullerenes with metal impurities containing Sc and Y. Substantial electron transfer from the metal core to the fullerene cage combines with electron backdonation, involving the interaction between the occupied orbitals of the negatively charged cage and the unoccupied d orbitals of the positively charged core. The Hueckel 4n+2 rule, well established in organic chemistry, is shown to provide a valuable heuristic tool for understanding the intramolecular electron transfer and the related stability gain /1/. The usefulness of the aromaticity concept for explaining and predicting the architecture of metallofullerenes is further exemplified by the units Sc2@C84 and Y2@C84 which were analyzed in spin triplet and singlet conditions. The Sc2 core turns out to be realized by two separated ions, while Y2 forms a bound subunit. These findings are in agreement with conclusions based on the 4n + 2 rule, assisted by Nucleus Independent Chemical Shift (NICS) calculations. /1/ Stevenson, S.; Fowler, P.W.; Heine, T.; Duchamp, J.C.; Rice, G.; Glass, T.; Harich, K.; Hadju, F.; Bible, R.; Dorn, H.C. Nature, 2000, 408, 427, /2/ S. S. Park, D. Liu, F. Hagelberg, J. Phys. Chem. A 109, 8865 (2005).

  10. EFFECT OF SCANDIUM ON HIDROGEN DISSOCIATION ENERGY AT MAGNESIUM SURFACE: AB INITIO DFT STUDY

    Directory of Open Access Journals (Sweden)

    I Wayan Sutapa

    2010-07-01

    Full Text Available The dissociative chemisorption of hydrogen on both pure and Sc-incorporated Mg(0001 surfaces have been studied by ab initio density functional theory (DFT calculation. The calculated dissociation energy of hydrogen molecule on a pure Mg(0001 surface (1.200 eV is in good agreement with comparable theoretical studies. For the Sc-incorporated Mg(0001 surface, the activated barrier decreases to 0.780 eV due to the strong interaction between the molecular orbital of hydrogen and the d metal state of Sc. This could explain the experimentally observed improvement in absorption kinetics of hydrogen when transition metals have been introduced into the magnesium materials.   Keywords: Dissociation, Adsorption, Chemisorptions, DFT, Magnesium

  11. Isolated hepatic perfusion as a treatment for uveal melanoma liver metastases (the SCANDIUM trial)

    DEFF Research Database (Denmark)

    Olofsson, Roger; Ny, Lars; Eilard, Malin Sternby

    2014-01-01

    BACKGROUND: Uveal melanoma is the most common primary intraocular malignancy in adults. Despite successful control of the primary tumor, metastatic disease will ultimately develop in approximately 50% of patients, with the liver being the most common site for metastases. The median survival...... of the longest surviving patients in Sweden during the same time period (26 versus 12 months). METHODS/DESIGN: This is the protocol for a multicenter phase III trial randomizing patients with isolated liver metastases of uveal melanoma to IHP or best alternative care (BAC). Inclusion criteria include liver...

  12. Hydrogen bonding induced polymorphism in the scandium(III) complex with ε-caprolactam

    Energy Technology Data Exchange (ETDEWEB)

    Virovets, Alexander V.; Peresypkina, Eugenia V. [Institute of Inorganic Chemistry SB RAS, Novosibirsk (Russian Federation); Novosibirsk State Univ. (Russian Federation); Cherkasova, Elizaveta V.; Cherkasova, Tatjana G. [Kuzbass State Technical Univ., Kemerovo (Russian Federation)

    2015-11-01

    Two polymorphs of [Sc(cpl){sub 6}][Cr(NCS){sub 6}] (cpl=ε- C{sub 6}H{sub 11}NO), trigonal and monoclinic, form purple elongated narrow plates and brownish-purple prisms and are formed concomitantly irrespectively of the crystallization conditions. In the trigonal polymorph both cation and anion possess C{sub 3i} site symmetry while in the monoclinic form cation and anion lie on inversion centre and 2-fold axis respectively. The nature of the polymorphism traces back to a redistribution of inter- and intramolecular hydrogen bonds that causes different conformation of the complex cations, different hydrogen bonding and different molecular packings. The [Sc(cpl){sub 6}]{sup 3+} cations in the structure of the trigonal polymorph form intermolecular N(H)..S, and in the monoclinic form both N(H)..S inter- and N(H)..O intramolecular hydrogen bonds with NCS groups of [Cr(NCS){sub 6}]{sup 3-} and cpl ligands. This aggregation leads to chains, where the cations and the anions alternate, in the trigonal modification and to layers, in which each ion is surrounded by four counterions, in the monoclinic form. Both polymorphs possess thermochromic properties, and a reversible color change from light purple to dark green takes place at 470-475 K.

  13. Photoluminescence of Undoped, Semi-Insulating, and Mg-Implanted Indium Phosphide.

    Science.gov (United States)

    1979-12-01

    valence band. The hole can easily drift away from the magnesium impurity site since neig ’ boring electrons migrate to the site to fill the third...York: John Wiley and Sons , 1974. 10. Casasent, David. Electronic Circuits. New York: Quantum Publishers, Inc., 1973. 11. Kittel, C. Introduction to...Solid State Physics. New York: John Wiley and Sons , Inc., 1976. 12. Pankove, Jacques I. Optical Processes in Semiconductors. Englewood Cliffs NJ

  14. Emission channeling studies of Indium Phosphide at low temperatures at CERN-ISOLDE

    CERN Document Server

    Amorim, Lígia Marina; Wahl, Ulrich

    $^{111}$In radioactive atoms were implanted into a single crystal of InP. After annealing for lattice recovery of implantation defects, the lattice site location of $^{111}$In/$^{111}$Cd was studied with the emission channeling technique, from room temperature ( 300K) down to 50K at CERN-ISOLDE. This work aims to test a recently developed cooling station for emission channeling experiments. InP is a material with a relatively low Debye temperature, where significant changes of atomic vibrations are expected with temperature, thus providing an ideal test ground of the effects, which can be expected to influence the data, i.e., de-channeling from lattice vibration and changes of the root mean square displacement (r.m.s.) of the atomic position of the probe atom. In the future we intend to apply these studies to monitor individual impurities or lattice constituents, with temperature, upon phase transitions as well as studying lattice sites of dopants implanted at low temperature.

  15. Excitons into one-axis crystals of zinc phosphide (Zn3P2

    Directory of Open Access Journals (Sweden)

    D.M. Stepanchikov

    2009-01-01

    Full Text Available Theoretical study of excitons spectra is offered in this report as for Zn3P2 crystals. Spectra are got in the zero approach of the theory of perturbations with consideration of both the anisotropy of the dispersion law and the selection rules. The existence of two exciton series was found, which corresponds to two valence bands (hh, lh and the conductivity band (c. It is noteworthy that anisotropy of the dispersion law plus the existence of crystalline packets (layers normal to the main optical axis, both will permit the consideration of two-dimensional excitons too. The high temperature displaying of these 2D-exciton effects is not eliminated even into bulk crystals. The calculated values of the binding energies as well as the oscillator's strength for the optical transitions are given for a volume (3D and for two-dimensional (2D excitons. The model of energy exciton transitions and four-level scheme of stimulated exciton radiation for receiving laser effect are offered.

  16. Histopathological effect of sub-lethal concentration of aluminum phosphide (phostoxin on Clarias gariepinus juveniles

    Directory of Open Access Journals (Sweden)

    Kayode B. Olurin

    Full Text Available Abtsract: The study evaluated the effect of sub-lethal concentration of phostoxin on Clarias gariepinus juveniles. C. gariepinus juveniles belonging to the same cohort (40.1±1.2g; 18.1±1.1cm from a commercial fish farm were randomly placed ten in each of 15 plastic tanks containing 15 liters of water. They were exposed for 96 hrs to three sub-lethal concentrations (treatments of phostoxin (0.125, 0.250, 0.5mg L-1 and a phostoxin free control. At the end of 96 hrs exposure, they were dissected and the tissues need for histopathology removed and fixed in Bouin's fluid. The gill filament exhibited fusion at the secondary lamella that was progressive with concentration. At the highest concentration of exposure, the secondary lamellae showed marked pyknotic and necrotic changes characterized by epithelia detachment. The hepatic tissue showed mild inflammatory changes at lower concentrations while at the highest concentration of exposure there was marked inflammation with observed hydropic degeneration. In the kidney, an inflammatory change was only observed in the interstices at the highest dose of exposure with the convoluted tubules showing partial shrinkage. Phostoxin showed to have significantly caused alterations in cyto-architecture of the gills and to a considerable extent liver and kidney of C. gariepinus.

  17. Studies of electron traps in gallium arsenide and gallium arsenide phosphide by deep level transient spectroscopy

    Science.gov (United States)

    Day, D. Y. S.

    1980-03-01

    System effects and data analysis for deep level transient spectroscopy (DLTS) have been examined and applied to study the deel levels in the GaAs-GaP system. Studies of typical DLTS systems using either the lock-in amplifier or the dual-channel boxcar averager are presented. The effects of non-zero gate width for the boxcar averager, phase angle adjustment for the lock-in amplifier, and response time of a typical commercial capacitance meter are investigated. Errors introduced in the measurements by these effects are calculated for typical cases. Measurements of gold level in silicon are presented, along with calculated corrections. We find the correction to be minimal in the boxcar-averager method, but significant in the lock-in amplifier approach. A DLTS system is described for measuring deep levels in diodes exhibiting large leakage currents. A capacitance bridge is used employing the diode to be tested along with a dummy diode of similar characteristics. The DLTS spectrum of a leaky GaAs planar diode is measured and compared to experimental results obtained with two standard DLTS systems . It is shown that measurements with the standard systems are impossible in certain temperature ranges because of overloading problems. The approach described here, however, gives the DLTS spectrum between 77 K and 300 K.

  18. Indium Phosphide-Based Quantum Dots with Shell-Enhanced Absorption for Luminescent Down-Conversion.

    Science.gov (United States)

    Dupont, Dorian; Tessier, Mickael D; Smet, Philippe F; Hens, Zeger

    2017-08-01

    It is shown that admixing small amounts of cadmium into the shell of InP/ZnSe core/shell quantum dots results in an increased absorption of blue light and a limited redshift of the band-edge emission. These effects reflect the reduced bandgap of (Zn,Cd)Se alloys and their smaller conduction-band offset with InP. Nevertheless, adjusting the InP core size enables InP/ZnSe and InP/(Zn,Cd)Se quantum dots with identical emission characteristics to be made. Processing both materials into remote phosphor disks, it is demonstrated that the shell-enhanced absorbance of InP/(Zn,Cd)Se has the double benefit of suppressing self-absorption and reducing the amount of quantum dots by weight needed to attain a given blue-to-red color conversion. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. High Sensitivity Indium Phosphide Based Avalanche Photodiode Focal Plane Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to build a monolithically integrated FPA of densely packed APDs (70-um pitch) operating at or around 1500 nm wavelength that is suitable for the solicited...

  20. Development of Ultra-Low Resistance Ohmic Contacts for indium gallium arsenide/indium phosphide HBTs

    Science.gov (United States)

    Baraskar, Ashish

    With the continued scaling of transistors to obtain increased transistor bandwidth and packing density, achieving very low resistance metal-semiconductor contacts becomes crucial. The base and emitter contact resistivities in heterojunction bipolar transistors (HBTs) must decrease in proportion to the inverse square of the transistor cutoff frequency. Similarly for field-effect transistors (FETs), progressive reduction in contact resistivity is required for both increased speed of operation and increased device packing density. Contact resistivities less than 10-8 O-cm2 are required for III-V HBTs and FETs for having simultaneous 1.5 THz current-gain (ft) and power-gain (fmax) cut-off frequencies. Owing to higher electron velocity, higher transistor bandwidths are more readily obtained in InGaAs than in Si, hence there is strong motivation to develop low resistance ohmic contacts to InGaAs. This dissertation focuses on development of ultra-low resistance ohmic contacts to n-In0.53Ga0.47As, n-InAs and p-In0.53 Ga0.47As for their application in InP based HBTs. There were four main challenges in obtaining ultra-low contact resistivities: 1. High doping: Attainment of high active carrier concentration which is required for reducing the depletion region in the semiconductor. Reduced depletion region results in enhanced tunneling of carriers across the metal semiconductor junction. 2. Surface preparation: Contact resistivity strongly depends on surface preparation and obtaining resistivities less than 10-8 O-cm 2 requires a significant attention to removal of semiconductor surface oxides before the contacts are made. 3. Refractory metal contact: Owing to high current densities (≈ 50 mA/mum2) and high temperatures involved during fabrication of scaled HBTs and FETs, it becomes important to keep the metal semiconductor junctions thermally stable for their continued operation as desired. To achieve thermal stability, it is required to use refractory metals for making the contact. 4. Accurate extraction of contact resistivities. In this work, molecular beam epitaxy thin-film growth technique was used to grow the semiconductor thin films. After careful growth optimization and calibrations, the highest active carrier concentration obtained was 6 x 1019 cm-3, 1 x 1020 cm -3 (record highest) and 2.2 x 1020 cm -3 for n-In0.53Ga0.47As, n-InAs and p-In 0.53Ga0.47As, respectively. W, Mo and Ir refractory metals were chosen to form contacts to these semiconductors to achieve thermal stability. Transmission line model structures were designed to accurately determine the contact resistivities. The lowest contact resistivities obtained were (0.9 +/- 0.5) x 10-8 O-cm2, (0.6 +/- 0.4) x 10-8 O-cm2 and (0.6 +/- 0.5) x 10-8 O-cm2 for contacts to n- In0.53Ga0.47As, n-InAs and p-In0.53Ga 0.47As, respectively, which are the lowest contact resistivities reported to date for these semiconductors. Contacts to n-In0.53Ga0.47 As and n-InAs were found to remain thermally stable. However, slight degradation on annealing was observed for contacts made to p-In0.53Ga 0.47As. We have also developed theoretical models to validate our experimental data. The models are extended to calculate the lowest possible contact resistivities for GaAs, InP, InSb and GaSb. In summary, the ultra-low resistance, refractory metal contacts developed in this work make them a potential candidate to be applied in highly scaled HBTs and other devices of near-terahertz bandwidths.

  1. Radiation and temperature effects in gallium arsenide, indium phosphide, and silicon solar cells

    Science.gov (United States)

    Weinberg, I.; Swartz, C. K.; Hart, R. E., Jr.; Statler, R. L.

    1987-01-01

    The effects of radiation on performance are determined for both n+p and p+n GaAs and InP cells and for silicon n+p cells. It is found that the radiation resistance of InP is greater than that of both GaAs and Si under 1-MeV electron irradiation. For silicon, the observed decreased radiation resistance with decreased resistivity is attributed to the presence of a radiation-induced boron-oxygen defect. Comparison of radiation damage in both p+n and n+p GaAs cells yields a decreased radiation resistance for the n+p cell attributable to increased series resistance, decreased shunt resistance, and relatively greater losses in the cell's p-region. For InP, the n+p configuration is found to have greater radiation resistance than the p+n cell. The increased loss in this latter cell is attributed to losses in the cell's emitter region. Temperature dependency results are interpreted using a theoretical relation for dVoc/dT, which predicts that increased Voc should result in decreased numerical values for dPm/dT. The predicted correlation is observed for GaAs but not for InP, a result which is attributed to variations in cell processing.

  2. High Sensitivity Indium Phosphide Based Avalanche Photodiode Focal Plane Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — nLight has demonstrated highly-uniform APD arrays based on the highly sensitive InGaAs/InP material system. These results provide great promise for achieving the...

  3. The structural evolution and diffusion during the chemical transformation from cobalt to cobalt phosphide nanoparticles

    KAUST Repository

    Ha, Don-Hyung

    2011-01-01

    We report the structural evolution and the diffusion processes which occur during the phase transformation of nanoparticles (NPs), ε-Co to Co 2P to CoP, from a reaction with tri-n-octylphosphine (TOP). Extended X-ray absorption fine structure (EXAFS) investigations were used to elucidate the changes in the local structure of cobalt atoms which occur as the chemical transformation progresses. The lack of long-range order, spread in interatomic distances, and overall increase in mean-square disorder compared with bulk structure reveal the decrease in the NP\\'s structural order compared with bulk structure, which contributes to their deviation from bulk-like behavior. Results from EXAFS show both the Co2P and CoP phases contain excess Co. Results from EXAFS, transmission electron microscopy, X-ray diffraction, and density functional theory calculations reveal that the inward diffusion of phosphorus is more favorable at the beginning of the transformation from ε-Co to Co2P by forming an amorphous Co-P shell, while retaining a crystalline cobalt core. When the major phase of the sample turns to Co 2P, the diffusion processes reverse and cobalt atom out-diffusion is favored, leaving a hollow void, characteristic of the nanoscale Kirkendall effect. For the transformation from Co2P to CoP theory predicts an outward diffusion of cobalt while the anion lattice remains intact. In real samples, however, the Co-rich nanoparticles continue Kirkendall hollowing. Knowledge about the transformation method and structural properties provides a means to tailor the synthesis and composition of the NPs to facilitate their use in applications. © 2011 The Royal Society of Chemistry.

  4. Regulating Water-Reduction Kinetics in Cobalt Phosphide for Enhancing HER Catalytic Activity in Alkaline Solution.

    Science.gov (United States)

    Xu, Kun; Ding, Hui; Zhang, Mengxing; Chen, Min; Hao, Zikai; Zhang, Lidong; Wu, Changzheng; Xie, Yi

    2017-07-01

    Electrochemical water splitting to produce hydrogen renders a promising pathway for renewable energy storage. Considering limited electrocatalysts have good oxygen-evolution reaction (OER) catalytic activity in acid solution while numerous economical materials show excellent OER catalytic performance in alkaline solution, developing new strategies that enhance the alkaline hydrogen-evolution reaction (HER) catalytic activity of cost-effective catalysts is highly desirable for achieving highly efficient overall water splitting. Herein, it is demonstrated that synergistic regulation of water dissociation and optimization of hydrogen adsorption free energy on electrocatalysts can significantly promote alkaline HER catalysis. Using oxygen-incorporated Co 2 P as an example, the synergistic effect brings about 15-fold enhancement of alkaline HER activity. Theory calculations confirm that the water dissociation free energy of Co 2 P decreases significantly after oxygen incorporation, and the hydrogen adsorption free energy can also be optimized simultaneously. The finding suggests the powerful effectiveness of synergetic regulation of water dissociation and optimization of hydrogen adsorption free energy on electrocatalysts for alkaline HER catalysis. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. DWDM laser arrays fabricated using thermal nanoimprint lithography on Indium Phosphide substrates

    DEFF Research Database (Denmark)

    Smistrup, K.; Nørregaard, J.; Mironov, A.

    Dense Wavelength Division Multiplexing (DWDM) lasers play a major role in today’s long-haul broadband communication. Typical distributed feedback (DFB) laser cavities consist of long half-pitch gratings in InGaAsP on InP substrates with pitches around 240 nm. Lasers are made reliably single mode...

  6. Electronic structure and optical properties of doped gallium phosphide: A first-principles simulation

    Science.gov (United States)

    Lu, Xuefeng; Gao, Xu; Li, Cuixia; Ren, Junqiang; Guo, Xin; La, Peiqing

    2017-09-01

    Using DFT-GGA-PW91 calculations we investigate the electronic structures and optical properties of doped GaP. It is found that the lattice constants and volume increase slightly for Al, In, As and Sb doped systems and EG distinctly decrease after doping. The formation energies are 0.587 and 0.273 eV for As and Sb doped systems, respectively, and lower remarkably than those in other systems, indicating that the stability of the two systems is higher. The direct band gap transition occurs when doped with In, As and Sb elements. The charge density difference images reveal that electron loss near Al atom is observed accompanying the enhancement of covalent bond feature, and then electron enrichment is present around N atom demonstrating that the ionic bond characteristic is obvious. The Sb-doped system has the higher static dielectric constant illustrating the applications in semiconductor devices. The absorption peak value is located at 194.7 nm for Al-doped system and this shows that the system can absorb a large amount of light and displays ;Barrier-type; characteristics in UV region. In the visible region, the doped systems have lower reflectivity coefficient, indicating that the systems all have ;clear-type; properties. This is conducive to fundamentally insights to a tunable band gap semiconductor with enormous potential in device fields.

  7. Hard X-ray detection with a gallium phosphide Schottky diode

    Energy Technology Data Exchange (ETDEWEB)

    Owens, Alan [Science Payload and Advanced Concepts Office, ESA/ESTEC, Postbus 299, 2200AG Noordwijk (Netherlands)], E-mail: aowens@rssd.esa.int; Andersson, S.; Hartog, R. den; Quarati, F. [Science Payload and Advanced Concepts Office, ESA/ESTEC, Postbus 299, 2200AG Noordwijk (Netherlands); Webb, A.; Welter, E. [HASYLAB at DESY, Notkestrasse 85, D-22607 Hamburg (Germany)

    2007-11-01

    We report on the detection of hard X-rays using a GaP Schottky diode at the HASYLAB synchrotron radiation research facility. Exposure to alpha particles from an {sup 214}Am source showed that the device was spectroscopic at room temperature with a FWHM energy resolution of 3.5% at 5.5 MeV. It was also found to be responsive to X-rays in the range 11-100 keV. Although individual energies are not spectrally resolved there is a proportionality of response to increasing X-ray energy. A two-dimensional scan of the sensitive area using a 30x30 {mu}m{sup 2} 30 keV pencil beam showed the spatial response of the detector to be uniform at the few percent level, consistent with statistics.

  8. Polycrystalline indium phosphide on silicon by indium assisted growth in hydride vapor phase epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Metaferia, Wondwosen; Sun, Yan-Ting, E-mail: yasun@kth.se; Lourdudoss, Sebastian [Laboratory of Semiconductor Materials, Department of Materials and Nano Physics, KTH—Royal Institute of Technology, Electrum 229, 164 40 Kista (Sweden); Pietralunga, Silvia M. [CNR-Institute for Photonics and Nanotechnologies, P. Leonardo da Vinci, 32 20133 Milano (Italy); Zani, Maurizio; Tagliaferri, Alberto [Department of Physics Politecnico di Milano, P. Leonardo da Vinci, 32 20133 Milano (Italy)

    2014-07-21

    Polycrystalline InP was grown on Si(001) and Si(111) substrates by using indium (In) metal as a starting material in hydride vapor phase epitaxy (HVPE) reactor. In metal was deposited on silicon substrates by thermal evaporation technique. The deposited In resulted in islands of different size and was found to be polycrystalline in nature. Different growth experiments of growing InP were performed, and the growth mechanism was investigated. Atomic force microscopy and scanning electron microscopy for morphological investigation, Scanning Auger microscopy for surface and compositional analyses, powder X-ray diffraction for crystallinity, and micro photoluminescence for optical quality assessment were conducted. It is shown that the growth starts first by phosphidisation of the In islands to InP followed by subsequent selective deposition of InP in HVPE regardless of the Si substrate orientation. Polycrystalline InP of large grain size is achieved and the growth rate as high as 21 μm/h is obtained on both substrates. Sulfur doping of the polycrystalline InP was investigated by growing alternating layers of sulfur doped and unintentionally doped InP for equal interval of time. These layers could be delineated by stain etching showing that enough amount of sulfur can be incorporated. Grains of large lateral dimension up to 3 μm polycrystalline InP on Si with good morphological and optical quality is obtained. The process is generic and it can also be applied for the growth of other polycrystalline III–V semiconductor layers on low cost and flexible substrates for solar cell applications.

  9. Heterodyne pump probe measurements of nonlinear dynamics in an indium phosphide photonic crystal cavity

    DEFF Research Database (Denmark)

    Heuck, Mikkel; Combrié, S.; Lehoucq, G.

    2013-01-01

    Using a sensitive two-color heterodyne pump-probe technique, we investigate the carrier dynamics of an InP photonic crystal nanocavity. The heterodyne technique provides unambiguous results for all wavelength configurations, including the degenerate case, which cannot be investigated with the wid...

  10. Modifications of gallium phosphide single crystals using slow highly charged ions and swift heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    El-Said, A.S., E-mail: elsaid@kfupm.edu.sa [Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Wilhelm, R.A.; Heller, R.; Akhmadaliev, Sh.; Schumann, E. [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden (Germany); Sorokin, M. [National Research Centre ’Kurchatov Institute’, Kurchatov Square 1, 123182 Moscow (Russian Federation); Facsko, S. [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden (Germany); Trautmann, C. [GSI Helmholtz Centre for Heavy Ion Research, 64291 Darmstadt (Germany); Technische Universität Darmstadt, 64289 Darmstadt (Germany)

    2016-09-01

    GaP single crystals were irradiated with slow highly charged ions (HCI) using 114 keV {sup 129}Xe{sup (33–40)+} and with various swift heavy ions (SHI) of 30 MeV I{sup 9+} and 374 MeV–2.2 GeV {sup 197}Au{sup 25+}. The irradiated surfaces were investigated by scanning force microscopy (SFM). The irradiations with SHI lead to nanohillocks protruding from the GaP surfaces, whereas no changes of the surface topography were observed after the irradiation with HCI. This result indicates that a potential energy above 38.5 keV is required for surface nanostructuring of GaP. In addition, strong coloration of the GaP crystals was observed after irradiation with SHI. The effect was stronger for higher energies. This was confirmed by measuring an increased extinction coefficient in the visible light region.

  11. Gallium phosphide as a new material for anodically bonded atomic sensors

    Directory of Open Access Journals (Sweden)

    Nezih Dural

    2014-08-01

    Full Text Available Miniaturized atomic sensors are often fabricated using anodic bonding of silicon and borosilicate glass. Here we describe a technique for fabricating anodically bonded alkali-metal cells using GaP and Pyrex. GaP is a non-birefringent semiconductor that is transparent at alkali-metal resonance wavelengths, allowing new sensor geometries. GaP also has a higher thermal conductivity and lower He permeability than borosilicate glass and can be anodically bonded below 200 °C, which can also be advantageous in other vacuum sealing applications.

  12. Indium tin oxide and indium phosphide heterojunction nanowire array solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, Masatoshi, E-mail: yoshimura@rciqe.hokudai.ac.jp; Nakai, Eiji; Fukui, Takashi [Graduate School of Information Science and Technology, and Research Center for Integrated Quantum Electronics (RCIQE), Hokkaido University, Kita 13 Nishi 8, Sapporo 060–8628 (Japan); Tomioka, Katsuhiro [Graduate School of Information Science and Technology, and Research Center for Integrated Quantum Electronics (RCIQE), Hokkaido University, Kita 13 Nishi 8, Sapporo 060–8628 (Japan); PRESTO, Japan Science and Technology Agency (JST), Honcho Kawaguchi, 332–0012 Saitama (Japan)

    2013-12-09

    Heterojunction solar cells were formed with a position-controlled InP nanowire array sputtered with indium tin oxide (ITO). The ITO not only acted as a transparent electrode but also as forming a photovoltaic junction. The devices exhibited an open-circuit voltage of 0.436 V, short-circuit current of 24.8 mA/cm{sup 2}, and fill factor of 0.682, giving a power conversion efficiency of 7.37% under AM1.5 G illumination. The internal quantum efficiency of the device was higher than that of the world-record InP cell in the short wavelength range.

  13. Synthesis and characterization of hollow spherical copper phosphide (Cu 3P) nanopowders

    Science.gov (United States)

    Liu, Shuling; Qian, Yitai; Xu, Liqiang

    2009-03-01

    In this paper, hollow spherical Cu 3P nanopowders were synthesized by using copper sulfate pentahydrate (CuSO 4ṡ5H 2O) and yellow phosphorus in a mixed solvent of glycol, ethanol and water at 140-180 ∘C for 12 h. X-ray powder diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), electron diffraction pattern (ED) and transmission electronic microscopy (TEM) studies show that the as-synthesized nanocrystal is pure hexagonal phase Cu 3P with a hollow spherical morphology. Based on the TEM observations, a possible aggregation growth mechanism was proposed for the formation of Cu 3P hollow structures. Meanwhile, the effects of some key factors such as solvents, reaction temperature and reaction time on the final formation of the Cu 3P hollow structure were also discussed.

  14. Sea urchin-like cobalt-iron phosphide as an active catalyst for oxygen evolution reaction

    Science.gov (United States)

    Mendoza-Garcia, Adriana; Su, Dong; Sun, Shouheng

    2016-02-01

    Sea urchin-like (CoxFe1-x)2P shows Co/Fe-composition dependent catalysis for oxygen evolution reaction (OER) in 0.1 M KOH. The (Co0.54Fe0.46)2P is the most efficient OER catalyst, reaching 10 mA cm-2 at an overpotential of 0.37 V (vs. RHE). The report offers a new synergistic approach to tune and optimize the electrocatalysis of OER.Sea urchin-like (CoxFe1-x)2P shows Co/Fe-composition dependent catalysis for oxygen evolution reaction (OER) in 0.1 M KOH. The (Co0.54Fe0.46)2P is the most efficient OER catalyst, reaching 10 mA cm-2 at an overpotential of 0.37 V (vs. RHE). The report offers a new synergistic approach to tune and optimize the electrocatalysis of OER. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08763e

  15. Quasi-two-dimensional metallic hydrogen inside di-phosphide at high pressure

    OpenAIRE

    Degtyarenko, Nikolay; Mazur, Evgeny

    2016-01-01

    The method of mathematical modeling was used for the calculation of the structural, electronic, phonon, and other characteristics of various normal phases of phosphorus hydrides with stoichiometry PHk. It was shown that the di-phosphine may form 2D lattice of the metallic hydrogen, stabilized by phosphorus atoms under high hydrostatic compressive pressure. The resulting structure with the elements of H-P-H is a locally stable one in the phonon spectrum (or metastable). The properties of di-ph...

  16. Mossbauer study of a complex /sup 119/Sn impurity-defect in gallium phosphide

    CERN Document Server

    Weyer, G; Heinemeier, J; Petersen, J W

    1980-01-01

    Reports the experiments utilising the intense secondary radioactive ion beams of the ISOLDE facility at CERN for implantations of /sup 119 /In/sup +/ into GaP single crystals. Impurity-defect structures have been studied by Mossbauer emission spectroscopy on the /sup 119/In daughter, /sup 119/Sn. Spectra measured within 4 min after the implantation and after an annealing of the sample at 255 degrees C for 1 min subsequent to the implantation have been presented. (8 refs).

  17. The platinum-rich scandium silicide Sc{sub 2}Pt{sub 9}Si{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Vosswinkel, Daniel; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

    2017-10-01

    Single crystals of Sc{sub 2}Pt{sub 9}Si{sub 3} have been obtained from an arc-melted and inductively annealed sample of the starting composition Sc:4Pt:2Si. The Sc{sub 2}Pt{sub 9}Si{sub 3} structure (Tb{sub 2}Pt{sub 9}Ge{sub 3} type, space group C2/c) was refined from single crystal X-ray diffractometer data: a=1303.4(1), b=749.9(1), c=973.5(1), β=116.44(1) {sup circle}, wR2=0.0731, 1643 F{sup 2} values and 67 variables. The structure contains three basic coordination polyhedra Sc rate at Pt{sub 11}, Si1 rate at Pt{sub 8} and Si2 rate at Pt{sub 8} which show a simple condensation pattern avoiding direct Sc-Si and Si-Si bonding.

  18. Effects of substituting ytterbium for scandium on the microstructure and age-hardening behaviour of Al–Sc alloy

    Energy Technology Data Exchange (ETDEWEB)

    Tuan, N.Q., E-mail: quoctuan1884@gmail.com [CT2M – Centre for Mechanical and Materials Technologies, University of Minho, Azurém, 4800-058 Guimarães (Portugal); Pinto, A.M.P.; Puga, H. [CT2M – Centre for Mechanical and Materials Technologies, University of Minho, Azurém, 4800-058 Guimarães (Portugal); Rocha, L.A. [CT2M – Centre for Mechanical and Materials Technologies, University of Minho, Azurém, 4800-058 Guimarães (Portugal); Universidade Estadual Paulista (Unesp), Faculdade de Ciências de Bauru, SP 17033-360 (Brazil); Barbosa, J. [CT2M – Centre for Mechanical and Materials Technologies, University of Minho, Azurém, 4800-058 Guimarães (Portugal)

    2014-04-01

    In order to reduce the cost of Al–Sc alloys and maintain their mechanical properties, the microstructure and mechanical properties of Al–0.24 wt% Sc–0.07 wt% Yb in comparison with Al–0.28 wt% Sc alloys were studied. The aging behaviour, precipitate morphologies, precipitate coarsening and precipitation hardening of both alloys were investigated. The average diameter and the size distribution of nanoscale Al{sub 3}Sc and Al{sub 3}(Sc,Yb) precipitates at various aging conditions were measured. Transmission electron microscopy (TEM) and high-resolution TEM were used to deeply understand the precipitate evolution. A maximum hardness around 73 (HV{sub 30}) was obtained with a precipitate diameter from 4.3 to 5.6 nm for both alloys.

  19. Phonon thermal conductivity of scandium nitride for thermoelectrics from first-principles calculations and thin-film growth

    Science.gov (United States)

    Kerdsongpanya, Sit; Hellman, Olle; Sun, Bo; Koh, Yee Kan; Lu, Jun; Van Nong, Ngo; Simak, Sergei I.; Alling, Björn; Eklund, Per

    2017-11-01

    The knowledge of lattice thermal conductivity of materials under realistic conditions is vitally important since many modern technologies require either high or low thermal conductivity. Here, we propose a theoretical model for determining lattice thermal conductivity, which takes into account the effect of microstructure. It is based on ab initio description that includes the temperature dependence of the interatomic force constants and treats anharmonic lattice vibrations. We choose ScN as a model system, comparing the computational predictions to the experimental data by time-domain thermoreflectance. Our experimental results show a trend of reduction in lattice thermal conductivity with decreasing domain size predicted by the theoretical model. These results suggest a possibility to control thermal conductivity by microstructural tailoring and provide a predictive tool for the effect of the microstructure on the lattice thermal conductivity of materials based on ab initio calculations.

  20. Influence of scandium addition on the high-temperature grain size stabilization of oxide-dispersion-strengthened (ODS) ferritic alloy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lulu, E-mail: lli18@ncsu.edu; Xu, Weizong; Saber, Mostafa; Zhu, Yuntian; Koch, Carl C.; Scattergood, Ronald O.

    2015-06-11

    The influence of 1–4 at% Sc addition on the thermal stability of mechanically alloyed ODS ferritic alloy was studied in this work. Sc addition was found to significantly stabilize grain size and microhardness at high temperatures. Grain sizes of samples with 1 and 4 at% Sc was found maintained in the nanoscale range at temperatures up to 1000 °C with hardness maintained at 5.6 and 6.7 GPa, respectively. The detailed microstructure was also investigated from EDS elemental mapping, where nanofeatures [ScTiO] were observed, while nanosized [YTiO] particles were rarely seen. This is probably due to the concentration difference between Sc and Y, leading to the formation of [ScTiO] favoring that of [YTiO]. Precipitation was considered as the major source for the observed high temperature stabilization. In addition, 14YT–Sc alloys without large second phases such as Ti-oxide can exhibit better performance compared to conventional ODS materials.

  1. The effect of composition on the mechanism of continuous recrystallization and superplastic response of aluminum-scandium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, III, Edwin Luther [Univ. of California, Berkeley, CA (United States)

    1993-05-01

    The continuous recrystallization (CRX) appears to be fundamental in Al-Sc because it occurs irrespective of solute composition. It appears to be due to a combination of subgrain coalescence at low strains and incorporation of additional dislocations generated during grain boundary sliding at higher strains when the misorientation has increased sufficiently. Alloying additives such as Mg, Li are more important with respect to deformation after CRX is completed. Mg, and to a lesser extent Li, affect the max m-values (strain-rate sensitivities) in Al-Sc by changing the melting points (mp). Max m- values correlate inversely with mp so that the alloy with the greatest Mg had the highest m-values and lowest mp; the stress is raised at which power-law creep and breakdown occurs. The power-law breakdonw at much lower stresses in Al-0.5Sc and Al-1.2Li-0.5Sc causes the m-value to decrease more rapidly with strain rate. Al alloys for commercial superplastic applications should contain elements that raise the power-law strength so that the m-values are maximized while preserving the post-formed mechanical properties. Refs, figs, tabs.

  2. Phonon thermal conductivity of scandium nitride for thermoelectrics from first-principles calculations and thin-film growth

    DEFF Research Database (Denmark)

    Kerdsongpanya, Sit; Hellman, Olle; Sun, Bo

    2017-01-01

    The knowledge of lattice thermal conductivity of materials under realistic conditions is vitally important since many modern technologies require either high or low thermal conductivity. Here, we propose a theoretical model for determining lattice thermal conductivity, which takes into account...

  3. Scandium and Titanium Containing Single-Walled Carbon Nanotubes for Hydrogen Storage: a Thermodynamic and First Principle Calculation

    National Research Council Canada - National Science Library

    Mananghaya, Michael; Yu, Dennis; Santos, Gil Nonato; Rodulfo, Emmanuel

    2016-01-01

    The generalized gradient approximation (GGA) to density functional theory (DFT) calculations indicate that the highly localized states derived from the defects of nitrogen doped carbon nanotube with divacancy (4ND-CNxNT...

  4. Nickel phosphide nanoparticles decorated nitrogen and phosphorus co-doped porous carbon as efficient hybrid catalyst for hydrogen evolution

    Science.gov (United States)

    Lin, Yan; Zhang, Jun; Pan, Yuan; Liu, Yunqi

    2017-11-01

    The design of efficient and robust Ni2P-based hybrid catalysts for hydrogen evolution reaction (HER) is still in challenge. In this work, a hybrid catalyst composed of monodispersed Ni2P nanoparticles (NPs) and N, P co-doped porous carbon (NPPC) was synthesized through a facile thermal decomposition and used as an efficient electrocatalyst for the HER in 0.5 M H2SO4 solution. Series technologies including X-ray diffraction, Raman, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and N2 sorption are used to characterize the as-synthesized catalysts. The electrochemisty experiments suggested that the as-synthesized Ni2P/NPPC displayed efficient electrocatalytic performance with a low onset overpotential (51 mV), small Tafel slope (74 mV dec-1), high exchange current density (0.12 mA cm-2), large electrochemical double-layer capacitance (21.97 mF cm-2) and high conductivity for the HER. The needed overpotentials are 159 and 184 mV to reach to the current density of 10 and 20 mA cm-2, respectively. Simultaneously, Ni2P/NPPC also displayed good stability in acid solution. The more defects and active sites on the porous carbon which are offered by the co-doped N and P atoms as well as the synergistic effect between NPPC and Ni2P NPs are contributed to the excellent catalytic performance for HER. The current study suggests that introducing the N, P heteroatoms co-doped carbon materials to the Ni2P-based catalysts could enhance HER electrocatalytic performance efficiently.

  5. Controlled Synthesis of Uniform Cobalt Phosphide Hyperbranched Nanocrystals Using Tri- n -octylphosphine Oxide as a Phosphorus Source

    KAUST Repository

    Zhang, Haitao

    2011-01-12

    A new method to produce hyperbranched Co 2P nanocrystals that are uniform in size, shape, and symmetry was developed. In this reaction tri-n-octylphosphine oxide (TOPO) was used as both a solvent and a phosphorus source. The reaction exhibits a novel monomer-saturation-dependent tunability between Co metal nanoparticle (NP) and Co 2P NP products. The morphology of Co 2P can be controlled from sheaflike structures to hexagonal symmetric structures by varying the concentration of the surfactant. This unique product differs significantly from other reported hyperbranched nanocrystals in that the highly anisotropic shapes can be stabilized as the majority shape (>84%). This is the first known use of TOPO as a reagent as well as a coordinating background solvent in NP synthesis. © 2011 American Chemical Society.

  6. Chip-scale white flip-chip light-emitting diode containing indium phosphide/zinc selenide quantum dots

    Science.gov (United States)

    Fan, Bingfeng; Yan, Linchao; Lao, Yuqin; Ma, Yanfei; Chen, Zimin; Ma, Xuejin; Zhuo, Yi; Pei, Yanli; Wang, Gang

    2017-08-01

    A method for preparing a quantum dot (QD)-white light-emitting diode (WLED) is reported. Holes were etched in the SiO2 layer deposited on the sapphire substrate of the flip-chip LED by inductively coupled plasma, and these holes were then filled with QDs. An ultraviolet-curable resin was then spin-coated on top of the QD-containing SiO2 layer, and the resin was cured to act as a protecting layer. The reflective sidewall structure minimized sidelight leakage. The fabrication of the QD-WLED is simple in preparation and compatible with traditional LED processes, which was the minimum size of the WLED chip-scale integrated package. InP/ZnS core-shell QDs were used as the converter in the WLED. A blue light-emitting diode with a flip-chip structure was used as the excitation source. The QD-WLED exhibited color temperatures from 5900 to 6400 K and Commission Internationale De L'Elcairage color coordinates from (0.315, 0.325) to (0.325, 0.317), under drive currents from 100 to 400 mA. The QD-WLED exhibited stable optoelectronic properties.

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

    Science.gov (United States)

    2011-03-01

    Russia semiconductor web: http://www.ioffe.ru/ SVA /NSM/Semicond/ 119 6.4 Refractive Index Measurements Refractive index measurements on wafer shaped...coefficient”, Appl. Phys. Lett. 66 (16) p2101-2103, (1995). 76. http://www.ioffe.ru/ SVA /NSM/Semicond 77. Sadao Adachi, “Band gaps and refractive indices

  8. Second harmonic generation in gallium phosphide microdisks on silicon: from strict \\bar{4} to random quasi-phase matching

    Science.gov (United States)

    Guillemé, P.; Dumeige, Y.; Stodolna, J.; Vallet, M.; Rohel, T.; Létoublon, A.; Cornet, C.; Ponchet, A.; Durand, O.; Léger, Y.

    2017-06-01

    The convergence of nonlinear optical devices and silicon photonics is a key milestone for the practical development of photonic integrated circuits. The associated technological issues often stem from material incompatibility. This is the case of second order nonlinear processes in monolithically integrated III-V semiconductor devices on silicon, where structural defects called antiphase domains strongly impact the optical properties of the material. We theoretically investigate the influence of antiphase domains on second harmonic generation in III-V whispering gallery mode microresonators on silicon and focus on the effects of the antiphase domains’ mean size (i.e. the correlation length of the distribution). We demonstrate that the domain distributions can have opposite effects depending on the nonlinear process under consideration: while antiphase domains negatively impact second harmonic generation under \\bar{4} quasi-phase matching conditions (independent of the correlation length), large conversion efficiencies can arise far from \\bar{4}-quasi-phase matching provided that the APD correlation length remains within an appropriate range, and is still compatible with the spontaneous emergence of such defects in the usual III-V on Si epilayers. Such a build-up can be explained by the occurrence of random quasi-phase matching in the system.

  9. Photoelectronic properties of zinc phosphide crystals, films and heterojunctions. Quarterly progress report No. 2, July 1-September 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Bube, R.H.

    1979-10-01

    The closed tube horizontal growth method has been pursued for the growth of single crystals of Zn/sub 3/P/sub 2/. The rate of material transport was increased by increasing the temperature difference between source and growth regions and by decreasing the distance involved. A boule with only 2 grains in a 12 mm diameter has been obtained. The as-grown resistivity of this single crystal Zn/sub 3/P/sub 2/ was 50 ohm-cm, which was reduced to 10 ohm-cm by subsequent annealing in hydrogen at 410/sup 0/C. Initial ZnO/Zn/sub 3/P/sub 2/ (CVD deposition of ZnO) and CdS/Zn/sub 3/P/sub 2/ (CdS by vacuum evaporation) heterostructures were fabricated using small samples of single crystal Zn/sub 3/P/sub 2/ sent from Tony Catalano at Delaware. Not surprisingly, only small photoresponse was obtained with these totally experimental cells. Zn/sub 3/P/sub 2/ films deposited on glass by CSVT were shown to be amorphous whereas those deposited on single crystal CdS were polycrystalline. Indeed several samples showed appreciable large-grain columnar growth at an angle to the substrate plane. Laser annealing was shown to have dramatic effects in crystallizing Zn/sub 3/P/sub 2/ films deposited on Si/sub 3/N/sub 4/ film substrates on sngle crystal Si. Thin films of Zn/sub 3/P/sub 2/ were deposited on glass substrates by vacuum evaporation. As-deposited film resistivities fell in the range of 10/sup 6/-10/sup 8/ ohm-cm; an apparently temporary decrease in resistivity by factors up to 50 could be obtained by annealing in hydrogen. Optical transmission and reflection spectra, as well as photoconductivity spectral response spectral response spectra were measured on a number of these films.

  10. International Conference on Indium Phosphide and Related Materials, Held in Cape Cod, Massachusetts, on 11 - 15 May 1997.

    Science.gov (United States)

    1998-01-14

    organometallic vapor deposition in Fig. 1. into porous glass [1], (ii) solution phase synthesis [2,3], and Palladium-purified hydrogen was used to carry the...M. H. Magnusson, Fabrication of GaN and InN of phosphor-us on the sample grid makes a reason- nanoparticles by aerosol technology (Master ofposition f...However at lower temperatures results in a high input resistance Ri. Thus the channel Antimony accumulation occurs at the top oxide charging delay

  11. The combined effect of titanic carbide and aluminum phosphide on the refinement of primary silicon in Al-50Si alloy

    Energy Technology Data Exchange (ETDEWEB)

    Dai Hongshang [Key Lab. of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong Univ., Jinan (China); Liu Xiangfa [Key Lab. of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong Univ., Jinan (China); Shandong Binzhou Bohai Piston Co., Ltd., Binzhou, SD (China)

    2008-12-15

    Two refinement methods for Al-50Si alloy are presented in this article: one way is using a newly developed Si-20P alloy at 1573 K: another technique is using the Si-20P alloy in company with Al-TiO{sub 2}-C mixture powder at 1473 K. Compared to the first method, the second one not only has better refinement effect on primary Si but also lower refinement temperature. These results are due to the combined effect of TiC and AlP on the refinement process, and the duplex TiC/AlP nucleus of primary silicon has been demonstrated using electron probe micro-analysis. Moreover, the reaction of Al-TiO{sub 2}-C mixture powder with increasing temperature was investigated using differential scanning calorimetry, which shows that the TiC particles are produced at about 1473 K. AlP particles combine with the in-situ TiC particles in the melt, which is the main reason for the formation of a duplex nucleus, and the disregistry between TiC and AlP in low-index planes is also discussed. (orig.)

  12. Antiphase domain tailoring for combination of modal and 4¯ -quasi-phase matching in gallium phosphide microdisks.

    Science.gov (United States)

    Guillemé, P; Vallet, M; Stodolna, J; Ponchet, A; Cornet, C; Létoublon, A; Féron, P; Durand, O; Léger, Y; Dumeige, Y

    2016-06-27

    We propose a novel phase-matching scheme in GaP whispering-gallery-mode microdisks grown on Si substrate combining modal and 4¯ -quasi-phase-matching for second-harmonic-generation. The technique consists in unlocking parity-forbidden processes by tailoring the antiphase domain distribution in the GaP layer. Our proposal can be used to overcome the limitations of form birefringence phase-matching and 4¯ -quasi-phase-matching using high order whispering-gallery-modes. The high frequency conversion efficiency of this new scheme demonstrates the competitiveness of nonlinear photonic devices monolithically integrated on silicon.

  13. Plasma-deposited germanium nitride gate insulators for indium phosphide metal-insulator-semiconductor field-effect transistors

    Science.gov (United States)

    Johnson, Gregory A.; Kapoor, Vik J.

    1991-01-01

    Plasma-deposited germanium nitride was investigated for the first time as a possible gate insulator for InP compound semiconductor metal-insulator-semiconductor FET (MISFET) technology. The germanium nitride films were successfully deposited in a capacitively coupled parallel plate reactor at 13.56 MHz operation using GeH4/N2/NH3 and GeH4/N2 mixtures as reactant gases. The former process produced better quality films with enhanced uniformity, increased deposition rates, and increased resistivity. The breakdown field strength of the films was greater than 10 to the 6th V/cm. Auger electron spectroscopy did not indicate significant chemical composition differences between the two processes. For MISFETs with 2-micron channel lengths fabricated on InP, the device transconductance and threshold voltage for the GeH4/N2/NH3 process were 17 mS/mm and -3.6 V, respectively. The drain-source breakdown voltages were greater than 10 V.

  14. Hessian fly (Diptera: Cecidomyiidae) mortality in export bale compressors and response to a hydrogen phosphide and carbon dioxide gas mixture

    Science.gov (United States)

    Hessian fly, Mayetiola destructor (Say), puparial mortality was evaluated in three modern hay compressors that produce compressed standard and large-size bales for export to Asia-Pacific countries. Pressure on bales ranged from 93.4-139.4 kg/cm² causing 90.0-99.9 % mortality of 10,891-23,164 puparia...

  15. Synthesis of Cobalt Phosphide Nanoparticles Supported on Pristine Graphene by Dynamically Self-Assembled Graphene Quantum Dots for Hydrogen Evolution.

    Science.gov (United States)

    Wang, Xiaoyan; Yuan, Weiyong; Yu, Yanan; Li, Chang Ming

    2017-03-09

    A highly active, durable, and low-cost hydrogen evolution reaction (HER) catalyst is desirable for energy storage through water splitting but its fabrication presents great challenges. Herein, mediated by dynamically self-assembled graphene quantum dots (GQDs), small, uniform, high-density, and well-dispersed CoP nanoparticles were grown in situ on pristine graphene for the first time. This hybrid nanostructure was then employed as HER electrocatalyst, showing an onset potential of 7 mV, an overpotential of 91.3 mV to achieve 10 mA cm-2 , a Tafel slope of 42.6 mV dec-1 , and an exchange current density of 0.1225 mA cm-2 , all of which compare favorably to those of most reported non-noble-metal catalysts. The developed catalyst also exhibits excellent durability with negligible current loss after 2000 cyclic voltammetry cycles (+0.01 to -0.17 V vs. RHE) or 34 h of chronoamperometric measurement at an overpotential of 91.3 mV. This work not only develops a new strategy for the fabrication of high-performance and inexpensive electrocatalysts for HER but also provides scientific insight into the mechanism of the dynamically self-assembled GQDsmediated synthesis process. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Thin polycrystalline films of indium phosphide on low-cost substrates. Quarterly report No. 3, April 3--July 2, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Ruth, R.P.; Dapkus, P.D.; Manasevit, H.M.; Campbell, A.G.; Hess, K.L.; Johnson, R.E.; Moudy, L.A.

    1977-07-01

    The program is intended to develop the metalorganic chemical vapor deposition (MO-CVD) process for growth of InP films using triethylindium (TEI) and phosphine (PH/sub 3/) reactants in a H/sub 2/ carrier gas, and then to prepare such films on inexpensive substrate materials for subsequent fabrication of heterojunction polycrystalline solar cells by deposition of CdS (or other semiconductor) on the InP. Minor changes in reactor design have permitted achievement of InP film growth rates up to four times larger than those previously obtained. Deposition conditions have been established for obtaining good-quality undoped n-type epitaxial InP films on single-crystal (111A) and (111B) InP substrates, and p-type Zn-doped epitaxial InP films have been produced on both GaAs and InP single-crystal substrates, with doping concentrations in the 10/sup 16/-10/sup 18/ cm/sup -3/ range. Experiments have continued on the growth of polycrystalline InP films on various low-cost substrates, including several glasses, metals and metal alloys, and intermediate layers of metals and semiconductors previously deposited on glass substrates; a wide range of InP film properties has been obtained in these studies, results of which are summarized. Experimental Schottky-barrier device structures, employing thin Au barrier layers, have been fabricated on p-type InP films prepared in various single- and multiple-layer configurations. Detailed characterization of the transport properties in both undoped n-type epitaxial InP films on GaAs : Cr and InP : Fe semi-insulating substrates and Zn-doped p-type epitaxial films on GaAs : Cr substrates is presented and discussed. The first heterojunction photovoltaic solar cell employing a vacuum-deposited n-type CdS film and an epitaxial p-type InP film grown by MO-CVD has been fabricated and characterized.

  17. Comparative evaluation of surface topography of tooth prepared using erbium, chromium: Yttrium, scandium, gallium, garnet laser and bur and its clinical implications

    Directory of Open Access Journals (Sweden)

    Mahesh Verma

    2015-01-01

    Conclusions: Er, Cr: YSGG laser can be used for preparing tooth and bond strength value achieved by laser preparation alone without surface treatment procedure lies in the range of clinical acceptability.

  18. IUPAC-NIST Solubility Data Series. 100. Rare Earth Metal Fluorides in Water and Aqueous Systems. Part 1. Scandium Group (Sc, Y, La)

    Energy Technology Data Exchange (ETDEWEB)

    Mioduski, Tomasz [Institute of Nuclear Chemistry and Technology, 03195 Warsaw (Poland); Gumiński, Cezary, E-mail: cegie@chem.uw.edu.pl [Department of Chemistry, University of Warsaw, 02093 Warsaw (Poland); Zeng, Dewen, E-mail: dewen-zeng@hotmail.com [College of Chemistry and Chemical Engineering, Central South University, 410083 Changsha (China)

    2014-03-15

    This work presents an assessment of solubility data for rare earth metal fluorides (generally of trivalent metals and of CeF{sub 4}) in water and in aqueous ternary systems. Compilations of all available experimental data are introduced for each rare earth metal fluoride with a corresponding critical evaluation. Every such evaluation contains a collection of all solubility results in water, a selection of suggested solubility data, and a brief discussion of the multicomponent systems. Because the ternary systems were seldom studied more than once, no critical evaluations of such data were possible. Only simple fluorides (no complexes or binary salts) are treated as the input substances in this report. The literature has been covered through the end of 2013.

  19. Enhanced magnetic and ferroelectric properties in scandium doped nano Bi{sub 2}Fe{sub 4}O{sub 9}

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Dimple P., E-mail: dimpled@barc.gov.in [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Sudakar, C.; Mocherla, Pavana S.V. [Department of Physics, IIT Madras, Chennai 600 036 (India); Mandal, Balaji P.; Jayakumar, Onnatu D. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Tyagi, Avesh K., E-mail: aktyagi@barc.gov.in [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2012-08-15

    In this study we report the synthesis of undoped and Sc{sup 3+} doped Bi{sub 2}Fe{sub 4}O{sub 9} nanoparticles using sonochemical technique. X-ray diffraction reveals that all samples are single phase with no impurities detected. EDS analysis was done to confirm the extent of Sc{sup 3+} doping in the samples. The size and morphology of the nanoparticles have been analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The Bi{sub 2}Fe{sub 4}O{sub 9} nanoparticles show a weak ferromagnetic behavior at room temperature, which is quite different from the linear M-H relationship reported for bulk Bi{sub 2}Fe{sub 4}O{sub 9}. A magnetization of 0.144 {mu}B/f.u. is obtained at 300 K, which is mainly attributed to the uncompensated moments at the disordered particle surface resulting from the reduced coordination of the surface spins, arising due to lattice strain or oxygen deficiency. Addition of Sc{sup 3+} dopant in varying concentrations in these Bi{sub 2}Fe{sub 4}O{sub 9} nanoparticles, improves their magnetic as well as ferroelectric properties. The leakage current is considerably reduced and electric polarization increases significantly in case of Bi{sub 2}Fe{sub 4(1-x)}Sc{sub x}O{sub 9} (x = 0.1) nanoparticles. Thus it can be inferred that Sc{sup 3+} doped Bi{sub 2}Fe{sub 4}O{sub 9} nanoparticles shows promise as good multiferroic materials. -- Graphical abstract: Undoped and Sc{sup 3+} doped Bi{sub 2}Fe{sub 4}O{sub 9} nanoparticles have been synthesized using sonochemical technique. The bi-functionalities of Sc{sup 3+} doped Bi{sub 2}Fe{sub 4}O{sub 9} nanoparticles have been demonstrated. The Bi{sub 2}Fe{sub 4(1-x)}Sc{sub x}O{sub 9} (x = 0.1) nanoparticles showed enhanced magnetic and ferroelectric properties with considerably less lossy characteristics compared to the bulk Bi{sub 2}Fe{sub 4}O{sub 9}. Highlights: Black-Right-Pointing-Pointer Phase pure Bi{sub 2}Fe{sub 4}O{sub 9} nanostructures synthesized using a facile sonochemical technique. Black-Right-Pointing-Pointer Nanoparticles show a weak ferromagnetic order at room temperature. Black-Right-Pointing-Pointer Sc{sup 3+} doping in Bi{sub 2}Fe{sub 4}O{sub 9} nanoparticles alters their magnetic and ferroelectric properties. Black-Right-Pointing-Pointer A magnetization of 0.166 {mu}B/f.u. was observed for Bi{sub 2}Fe{sub 4(1-x)}Sc{sub x}O{sub 9} (x = 0.1) nanoparticles. Black-Right-Pointing-Pointer It showed enhanced ferroelectric properties with less lossy characteristics.

  20. The effect of erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser therapy on pain during cavity preparation in paediatric dental patients: a pilot study.

    Science.gov (United States)

    Eren, Figen; Altinok, Basak; Ertugral, Ferhan; Tanboga, Ilknur

    2013-06-01

    Standard treatment for caries removal and cavity preparation for restorations using mechanical means is often accompanied by fear and pain for the patient. Although the pain may be reduced by local anaesthesia, fear of the needle, noise, and the vibration of mechanical preparation remain a cause of discomfort. Erbium, chromium:yttriumscandium- gallium-garnet (Er,Cr:YSGG) laser irradiation indicates that pain perception may be reduced relative to that caused by mechanical preparation. The aim of this pilot clinical study was to perform a preliminary evaluation of pain perception during cavity preparation comparing the mechanical removal and Er,Cr:YSGG laser removal of caries from enamel and dentine. The study sample was ten children aged 7 to 12 years. Half of the preparations were completed by the laser alone and the other half were mechanically prepared. All cavities were restored with light-cured composite resin following the application of acid etch and a bonding agent. The time spent on cavity preparation and the behaviour of the patients during cavity preparation were recorded. Children were instructed to rate their pain on a visual analogue scale. In addition, the patients were asked to decide which was the more uncomfortable form of treatment and the preferred treatment for future caries therapy. Children showed considerably more body and head movement with the conventional mechanical preparation. The subjects rated the perception of pain lower when the laser technique was used. In the small number of children studied, the application of the Er,Cr:YSGG laser system was a more comfortable alternative or adjunctive method to conventional mechanical cavity preparation. A far larger study is necessary to confirm this finding.

  1. Solution synthesis, structure, and CO{sub 2} reduction reactivity of a Scandium(II) complex, {Sc[N(SiMe_3)_2]_3}{sup -}

    Energy Technology Data Exchange (ETDEWEB)

    Woen, David H.; Chen, Guo P.; Ziller, Joseph W.; Furche, Filipp; Evans, William J. [Department of Chemistry, University of California, Irvine, CA (United States); Boyle, Timothy J. [Sandia National Laboratories, Advanced Materials Laboratory, Albuquerque, NM (United States)

    2017-02-13

    The first crystallographically characterizable complex of Sc{sup 2+}, [Sc(NR{sub 2}){sub 3}]{sup -} (R=SiMe{sub 3}), has been obtained by LnA{sub 3}/M reactions (Ln=rare earth metal; A=anionic ligand; M=alkali metal) involving reduction of Sc(NR{sub 2}){sub 3} with K in the presence of 2.2.2-cryptand (crypt) and 18-crown-6 (18-c-6) and with Cs in the presence of crypt. Dark maroon [K(crypt)]{sup +}, [K(18-c-6)]{sup +}, and [Cs(crypt)]{sup +} salts of the [Sc(NR{sub 2}){sub 3}]{sup -} anion are formed, respectively. The formation of this oxidation state of Sc is also indicated by the eight-line EPR spectra arising from the I=7/2 {sup 45}Sc nucleus. The Sc(NR{sub 2}){sub 3} reduction differs from Ln(NR{sub 2}){sub 3} reactions (Ln=Y and lanthanides) in that it occurs under N{sub 2} without formation of isolable reduced dinitrogen species. [K(18-c-6)][Sc(NR{sub 2}){sub 3}] reacts with CO{sub 2} to produce an oxalate complex, {K_2(18-c-6)_3}{[(R_2N)_3Sc]_2(μ-C_2O_4-κ"1O:κ"1O'')}, and a CO{sub 2}{sup -} radical anion complex, [(R{sub 2}N){sub 3}Sc(μ-OCO-κ{sup 1}O:κ{sup 1}O')K(18-c-6)]{sub n}. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Etudes optiques de nouveaux materiaux laser: Des orthosilicates dopes a l'ytterbium: Le yttrium (lutetium,scandium) pentoxide de silicium

    Science.gov (United States)

    Denoyer, Aurelie

    La decouverte et l'elaboration de nouveaux materiaux laser solides suscitent beaucoup d'interet parmi la communaute scientifique. En particulier les lasers dans la gamme de frequence du micron debouchent sur beaucoup d'applications, en telecommunication, en medecine, dans le domaine militaire, pour la, decoupe des metaux (lasers de puissance), en optique non lineaire (doublage de frequence, bistabilite optique). Le plus couramment utilise actuellement est le Nd:YAG dans cette famille de laser, mais des remplacants plus performants sont toujours recherches. Les lasers a base d'Yb3+ possedent beaucoup d'avantages compares aux lasers Nd3+ du fait de leur structure electronique simple et de leur deterioration moins rapide. Parmi les matrices cristallines pouvant accueillir l'ytterbium, les orthosilicates Yb:Y 2SiO5, Yb:Lu2SiO5 et Yb:Sc2SiO 5 se positionnent tres bien, du fait de leur bonne conductivite thermique et du fort eclatement de leur champ cristallin necessaire a l'elaboration de lasers quasi-3 niveaux. De plus l'etude fine et systematique des proprietes microscopiques de nouveaux materiaux s'avere toujours tres interessante du point de vue de la recherche fondamentale, c'est ainsi que de nouveaux modeles sont concus (par exemple pour le champ cristallin) ou que de nouvelles proprietes inhabituelles sont decouvertes, menant a de nouvelles applications. Ainsi d'autres materiaux dopes a l'ytterbium sont connus pour leurs proprietes de couplage electron-phonon, de couplage magnetique, d'emission cooperative ou encore de bistabilite optique, mais ces proprietes n'ont encore jamais ete mises en evidence dans Yb:Y 2SiO5, Yb:Lu2SiO5 et Yb:Sc2SiO 5. Ainsi, cette these a pour but l'etude des proprietes optiques et des interactions microscopiques dans Yb:Y2SiO 5, Yb:Lu2SiO5 et Yb:Sc2SiO5. Nous utilisons principalement les techniques d'absorption IR et de spectroscopie Raman pour determiner les excitations du champ cristallin et les modes de vibration dans le materiau. Des mesures optiques sous champ magnetique ont egalement ete effectuees dans le but de caracteriser le comportement de ces excitations lorsqu'elles sont soumises a l'effet Zeeman. La resonance paramagnetique electronique a permis de completer cette etude de l'eclatement Zeeman suivant toutes les orientations du cristal. Enfin la fluorescence par excitation selective et la fluorescence induite par Raman FT, completent la description des niveaux d'energie et revelent l'existence d'emission cooperative de deux ions Yb3+ et de transferts d'energie. Les resultats de cette these apportent une contribution originale dans le domaine des nouveaux materiaux lasers par l'etude et la comprehension des interactions fines et des proprietes microscopiques d'un materiau en particulier. Ils debouchent a la fois sur des applications possibles dans le domaine de l'optique et des lasers, et sur la comprehension d'aspects fondamentaux. Cette these a prouve l'interet de ces matrices pour leur utilisation comme lasers solides: un fort eclatement du champ cristallin favorable a l'elaboration de laser quasi-3 niveaux, et de larges bandes d'absorption (dues a un fort couplage electron-phonon et a des raies satellites causees par une interaction d'echange entre deux ions Yb3+) qui permettent la generation d'impulsions laser ultra-courtes, l'accordabilite du laser, etc. De plus la miniaturisation des lasers est possible pour l'optique integree grace a des couches minces synthetisees par epitaxie en phase liquide dont nous avons demontre la tres bonne qualite structurale et l'ajustement possible de certains parametres. Nous avons reconstruit le tenseur g du niveau fondamental (qui donne des informations precieuses sur les fonctions d'onde), ceci dans le but d'aider les theoriciens a concevoir un modele de champ cristallin valide. Plusieurs mecanismes de transferts d'energie ont ete mis en evidence: un mecanisme de relaxation d'un site vers l'autre, un mecanisme d'emission cooperative, et un mecanisme d'excitation de l'Yb3+ par le Tm3+ (impurete presente dans le materiau). Ces transferts sont plutot nefastes pour la fabrication d'un laser mais sont interessants pour l'optique non lineaire (doublage de frequence, memoires optiques). Enfin, plusieurs elements (le couplage magnetique de paire, le couplage electron-phonon et l'emission cooperative) nous ont permis de conclure sur le caractere covalent de la matrice. Nous avons d'ailleurs demontre ici le role de la covalence dans l'emission cooperative, transition habituellement attribuee aux interactions multipolaires electriques.

  3. The 6-amino-6-methyl-1,4-diazepine group as an ancillary ligand framework for neutral and cationic scandium and yttrium alkyls

    NARCIS (Netherlands)

    Ge, Shaozhong; Bambirra, Sergio; Meetsma, Auke; Hessen, Bart

    2006-01-01

    The 6-amino-6-methyl-1,4-diazepine framework is a readily available neutral 6-electron ligand moiety, suitable to support cationic group 3 metal alkyl catalysts; it also provides convenient access to tri- and tetradentate monoanionic ligand derivatives.

  4. Current German Laser and Quantum Optics Research Reviewed at the 50th Annual Meeting of the Physikalische Gesellschaft.

    Science.gov (United States)

    1986-04-23

    has a substantial crys- tingen) described studies with Cr- plus tal growing capability. One paper from Nd-doped gadolinium -scandium- gallium the Hamburg...institute, read by J. Drube, garnets (GSGG), and also with Cr-doped reported on Xe-flashlamp-pumped Cr:CSA(; % gadolinium -scandium- aluminum garnets...ele- scandium- aluminum garnets (YSA) :mdi..’ ments. yttrium-scandium- gallium garnets (YSC). The crystals used in the Spindler & Optical pumping (with a

  5. Tapping the potential of trioctylphosphine (TOP) in the realization of highly luminescent blue-emitting colloidal indium phosphide (InP) quantum dots

    Science.gov (United States)

    Singh, Akanksha; Chawla, Parul; Jain, Shefali; Sharma, Shailesh Narain

    2017-06-01

    In this work, extremely small blue emitting colloidal InP-based quantum dots (size 2-5 nm) have been synthesized using trioctylphosphine (TOP) as a source of phosphorus. The method reported here is unconventional, quite rapid ( 90 min), more viable, less expensive and relatively greener as compared to other conventional methods that employ tristrimethylsilyylphosphine(P(SiMe3)3) which is scarce, expensive, flammable, highly toxic and even banned in a few countries. Highly luminescent InP QDs having bluish-green emission (λ 490 nm) can be synthesized using this method without resorting to any post-synthesis etching to tune the emission to the blue region. Besides being the source of phosphorus and the particle size regulating agent, the efficacy of TOP is further realized during synthesis via its reduction of indium salt, which aids in the formation of indium metal and then subsequently in the development of InP QDs. The PL intensity of as-synthesized InP QDs is further enhanced by growing a shell of wide band gap material, i.e. ZnS resulting in a concurrent increment in quantum yield from 25% to 38% respectively.

  6. Sugar Blowing-Induced Porous Cobalt Phosphide/Nitrogen-Doped Carbon Nanostructures with Enhanced Electrochemical Oxidation Performance toward Water and Other Small Molecules

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Chengzhou [School of Mechanical and Materials Engineering, Washington State University, Pullman WA 99164 USA; Fu, Shaofang [School of Mechanical and Materials Engineering, Washington State University, Pullman WA 99164 USA; Xu, Bo Z. [School of Mechanical and Materials Engineering, Washington State University, Pullman WA 99164 USA; Song, Junhua [School of Mechanical and Materials Engineering, Washington State University, Pullman WA 99164 USA; Shi, Qiurong [School of Mechanical and Materials Engineering, Washington State University, Pullman WA 99164 USA; Engelhard, Mark H. [Environmental Molecular Science Laboratory, Pacific Northwest National Laboratory, Richland WA 99352 USA; Li, Xiaolin [Energy and Environmental Directory, Pacific Northwest National Laboratory, Richland WA 99352 USA; Beckman, Scott P. [School of Mechanical and Materials Engineering, Washington State University, Pullman WA 99164 USA; Sun, Junming [The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman WA 99164 USA; Du, Dan [School of Mechanical and Materials Engineering, Washington State University, Pullman WA 99164 USA; Lin, Yuehe [School of Mechanical and Materials Engineering, Washington State University, Pullman WA 99164 USA

    2017-06-28

    Finely controlled synthesis of high active and robust nonprecious metal catalysts with excellent catalytic efficiency in oxygen evolution reaction (OER) is extremely vital for making the water splitting process more energy-efficient and economical. Among these noble metal-free catalysts, transition-metal-based nanomaterials are considered as one of the most promising OER catalysts due to their relatively low-cost intrinsic activities, high abundance and diversity in terms of structure and morphology. In this work, we reported a facile sugar-blowing technique and low-temperature phosphorization to generate 3D self-supported metal involved carbon nanostructures, which termed as Co2P@Co/nitrogen-doped carbon (Co2P@Co/N-C). By capitalizing on the 3D porous nanostructures with high surface area, generously dispersed active sites, the intimate interaction between active sites and 3D N-doped carbon, the resultant Co2P@Co/N-C exhibited satisfying OER performance superior to CoO@Co/N-C, delivering 10 mA cm-2 at overpotential of 0.32 V. It is noting that in contrast to the substantial current density loss of RuO2, Co2P@Co/N-C showed much enhanced catalytic activity during the stability test and the 1.8-fold increase in current density was observed after stability test. Furthermore, the obtained Co2P@Co/N-C can also be served as an excellent nonprecious metal catalyst for methanol and glucose electrooxidation in alkaline media, further extending their potential applications.

  7. International Conference on Indium Phosphide and Related Materials (22nd) (IPRM) held on 31 May-4 Jun 2010, at Takamatsu Symbol Tower, Kagawa, Japan

    Science.gov (United States)

    2010-08-13

    Additionally, it is very challenging to achieve the wavelength accuracy required for DWDM or CWDM systems, and the combination with a monitor diode is...toward reconfigurable dense wavelength division multiplexed ( DWDM ) photonic network systems. They have been coming into wide use for the...Modulator lor DWDM Optical Communication Systems, " IEEE J. of Selected Topics in Quantum Electronics, vol. 15. no. 3. pp. 521-527. 2009. |2| S

  8. Scandium, Yttrium, and Lanthanum Benzyl and Alkynyl Complexes with the N-(2-Pyrrolidin-1-ylethyl)-1,4-diazepan-6-amido Ligand : Synthesis, Characterization, and Z-Selective Catalytic Linear Dimerization of Phenylacetylenes

    NARCIS (Netherlands)

    Ge, Shaozhong; Meetsma, Auke; Hessen, Bart

    2009-01-01

    1,4,6-Trimethyl-N-(2-pyrrolidin-1-ylethyl)-1,4-diazepan-6-amine (HL) reacts with M(CH(2)Ph)(3)(THF)(3) to give the dibenzyl complexes (L)M(CH(2)Ph)(2) (M = SC, 1; M = Y, 2; M = La, 3). Compounds 1, 2, and 3 can be converted to their corresponding cationic monobenzyl species [(L)M(CH(2)Ph)](+) (M =

  9. Hydride vapor phase epitaxy growth of GaN, InGaN, ScN, and ScAIN

    NARCIS (Netherlands)

    Bohnen, T.

    2010-01-01

    Chemical vapor deposition (CVD); hydride vapor phase epitaxy (HVPE); gallium nitride (GaN); indium gallium nitride (InGaN); scandium nitride (ScN); scandium aluminum nitride (ScAlN); semiconductors; thin films; nanowires; III nitrides; crystal growth - We studied the HVPE growth of different III

  10. The molecular beam epitaxy growth and characterization of zinc cadmium selenide/zinc cadmium magnesium selenide-indium phosphide quantum cascade structures for operation in the 3 - 5 um range

    Science.gov (United States)

    Charles, William O.

    The quantum cascade (QC) laser has captured the interest of researchers for almost three decades. In the early stages, researchers were very interested in proving the QC concept1 proposed by Kazarinov and Suris in 1971. This new concept gave researchers hope that very bulky energy inefficient infra-red (IR) lasers would be replaced with ones that are very compact, tunable and portable. Since the proposal of the QC laser concept and its first demonstration by researchers at Bell Laboratories2 in 1994, this technology has progressed to the point where it is now finding commercial applications in a variety of areas such as military counter measures, free space telecommunications, infra-red imaging and chemical spectroscopy.3-5 The success of this technology can be attributed to the coming of age of the techniques of molecular beam epitaxy (MBE) semiconductor growth and bandgap engineering. 6,7 Using MBE technology, the temperature of the source material can be stabilized by making use of a combination of proportional integral derivative (PID) controllers and thermocouple feedbacks. As a result, the material flux from the effusion cells can achieve stability better than (+/-) 1%. This flux stability together with a well-developed computer controlled shuttering mechanism make it possible to grow multi-quantum well (MQW) structures with excellent layer thickness precision (mono-layer scale) and interface quality. This stringent control of material flux is also a tool that is used by MBE growers to vary the material compositions for the growth of lattice matched and strain compensated QC structures. Today, MBE stands out as one of the premier methods for growing high performing QC lasers. The first successful demonstration of a QC laser2 was done using the InGaAs/InAlAs-InP material system. This demonstration was then repeated a few years later using GaAs/AlGaAs-InP.8 These III-V material systems were extensively studied to establish their material parameters. Given that material parameters are critically important in the process of modeling QC structures, it is not surprising that early success was achieved using these systems. Today, the best performing QC lasers operate in the 4--13 mum range and are produced using lattice matched InGaAs/InAlAs-InP. In order to produce short wavelength QC lasers, the well layer thicknesses in the active region of the device must be reduced in an effort to push the lasing energy states further apart. This reduction in well thicknesses results in the movement of the upper lasing state closer to the bandedge. This action increases the probability of the lost of lasing state electrons to the continuum. Therefore, in order to produce high performing short wavelength QC lasers, a large conduction band offset (CBO) is required. The CBO of lattice matched InGaAs/InAlAs-InP is 0.52 eV. In an attempt to produce high performing devices below 4 mum many researchers have resorted to the use of strain compensation9-11 . This approach has yielded very little improvement in performance due to electron scattering to the X and L intervalleys. This has lead to the exploration of wide bandgap material systems such as the antominides and nitrides. In this work the wide bandgap II-V Znx'Cd(1-x')Se/Zn xCdyMg(1-x-y)Se-InP will be explored for QC laser fabrication. To this end, QC lasers were designed for operation at 3--5 mum range. A Matlab-based program was written to calculate the energy level spacing within the active region of these devices. This simulation program was based on Schroindger's equation and the transfer matrix technique. Several calibration samples were grown to establish the doping levels and growth rate of the well and barrier materials. The growth rate was measured using scanning electron microscopy (SEM) and reflection high energy electron diffraction (RHEED) oscillations during MBE growth. X-ray diffraction measurements were performed to determine the lattice mismatch of the II-VI bulk layers, and therefore predict whether material composition adjustments were required to attain the lattice match condition. The samples that were grown were studied using photoluminescence (PL) to determine the bandgap of the well and barrier material. This information was then used to calculate the CBO of the II-VI MQW structure. In addition, PL studies were also carried out to look for material defects and assess the quality of the well/barrier interface. These II-VI QC samples were also subjected to Fourier transform infra-red (FTIR) absorption spectroscopy to determine the energy levels in the grown structures. After optimizing the active regions using simulation data and FTIR results, electroluminescence (EL) structures were grown and processed into QC emitters using a combination photolithography and electron beam contact deposition. The processed structures were then biased and investigated for IR emission at temperatures ranging from 80 K to room temperature.

  11. Synthesis and structural characterization of CsNiP crystal

    Indian Academy of Sciences (India)

    Unknown

    Fluck and Issleib 1965). However, studies of these alka- line metal phosphides gained momentum since last three decades (Johnson and Jeitschlo 1972; Barz et al 1983;. Muller et al 1983; Schnering et al 1999). In recent years, structural data of phosphides also were reported (Shan- non 1976; Jeitschlo and Braun 1977; ...

  12. Investigation of Possible Antidotal Effects of Activated Charcoal ...

    African Journals Online (AJOL)

    Investigation of Possible Antidotal Effects of Activated Charcoal, Sodium Bicarbonate, Hydrogen Peroxide and Potassium Permanganate in Zinc Phosphide ... Zinc phosphide, a commonly used rat poison in Kenya was mixed with maize flour in a concentration of 0.15 % w/w and fed to a group of 60 experimental mice for 3 ...

  13. Surround-gated vertical nanowire quantum dots

    NARCIS (Netherlands)

    Van Weert, M.H.M.; Den Heijer, M.; Van Kouwen, M.P.; Algra, R.E.; Bakkers, E.P.A.M.; Kouwenhoven, L.P.; Zwiller, V.

    2010-01-01

    We report voltage dependent photoluminescence experiments on single indium arsenide phosphide (InAsP) quantum dots embedded in vertical surround-gated indium phosphide (InP) nanowires. We show that by tuning the gate voltage, we can access different quantum dot charge states. We study the

  14. Temperature dependence of the 1.06-microm stimulated emission cross section of neodymium in YAG and in GSGG.

    Science.gov (United States)

    Rapaport, Alexandra; Zhao, Shengzhi; Xiao, Guohua; Howard, Andrew; Bass, Michael

    2002-11-20

    A linear temperature dependence between -70 degrees C and +70 degrees C is reported for the peak stimulated emission cross section of Nd3+ ions in both yttrium aluminum garnet (YAG) and gadolinium scandium gallium garnet (GSGG).

  15. Nano-Particle Scandate Cathode for Space Communications Phase 2 Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose an improved cathode based on our novel theory of the role of scandium oxide in enhancing emission in tungsten-impregnated cathodes. Recent results have...

  16. Nano-Particle Scandate Cathode for Space Communications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose an improved cathode based on our novel theory of the role of scandium oxide in enhancing emission in tungsten impregnate cathodes. Recent results have...

  17. Synthesis and Isolation of the Titanium-Scandium Endohedral Fullerenes-Sc2 TiC@Ih -C80 , Sc2 TiC@D5h -C80 and Sc2 TiC2 @Ih -C80 : Metal Size Tuning of the Ti(IV) /Ti(III) Redox Potentials.

    Science.gov (United States)

    Junghans, Katrin; Ghiassi, Kamran B; Samoylova, Nataliya A; Deng, Qingming; Rosenkranz, Marco; Olmstead, Marilyn M; Balch, Alan L; Popov, Alexey A

    2016-09-05

    The formation of endohedral metallofullerenes (EMFs) in an electric arc is reported for the mixed-metal Sc-Ti system utilizing methane as a reactive gas. Comparison of these results with those from the Sc/CH4 and Ti/CH4 systems as well as syntheses without methane revealed a strong mutual influence of all key components on the product distribution. Whereas a methane atmosphere alone suppresses the formation of empty cage fullerenes, the Ti/CH4 system forms mainly empty cage fullerenes. In contrast, the main fullerene products in the Sc/CH4 system are Sc4 C2 @C80 (the most abundant EMF from this synthesis), Sc3 C2 @C80 , isomers of Sc2 C2 @C82 , and the family Sc2 C2 n (2 n=74, 76, 82, 86, 90, etc.), as well as Sc3 CH@C80 . The Sc-Ti/CH4 system produces the mixed-metal Sc2 TiC@C2 n (2 n=68, 78, 80) and Sc2 TiC2 @C2 n (2 n=80) clusterfullerene families. The molecular structures of the new, transition-metal-containing endohedral fullerenes, Sc2 TiC@Ih -C80 , Sc2 TiC@D5h -C80 , and Sc2 TiC2 @Ih -C80 , were characterized by NMR spectroscopy. The structure of Sc2 TiC@Ih -C80 was also determined by single-crystal X-ray diffraction, which demonstrated the presence of a short Ti=C double bond. Both Sc2 TiC- and Sc2 TiC2 -containing clusterfullerenes have Ti-localized LUMOs. Encapsulation of the redox-active Ti ion inside the fullerene cage enables analysis of the cluster-cage strain in the endohedral fullerenes through electrochemical measurements. © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  18. The application of spectrographic analysis to the radioisotope production control. II. Analysis of calcium-45, scandium-46, nickel-63, and copper-64 solutions; Aplicacion del analisis espectrografico al control de produccion de radioisotopos. II. Analisis de soluciones de calcio-45, escandio-46, niquel-63 y cobre-64

    Energy Technology Data Exchange (ETDEWEB)

    Capdevila, C.; Roca, M.

    1972-07-01

    Semi-quantitative and quantitative determinations of both the radioactive and the target element in each radioisotope are described. The copper-spark technique was used except for Cu determinations, that need silver or.graphite electro des. Inter-element effects and their compensation through the use of Bi, 6a, In, Ho, Pd, TI and Y as reference elements was examined. For the determination of Ca in Ca-45 samples, Ba, La, Li and Sr were also tested. Good results are achieved with Li for Ca, Y for Sc,Ti and Ni, and either In or Y for Cu and Zn. (Author) 7 refs.

  19. Precision affinage of copper from crow-bar and wastes

    OpenAIRE

    Цыганкова, Ольга Васильевна

    2013-01-01

    The model of the deep copper refining from the secondary raw materials using methods of physical and chemical analysis was considered. The theoretical and experimental results of copper refining from the secondary raw materials using phosphide Cu3P were proposed. The copper phosphide Cu3P was added into melting during fire refining. The copper phosphide Cu3P influence on the refining level was estimated on the tin, lead, zink and antimony impurities. Reactions analysis showed that the Cu3P ad...

  20. 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.

  1. Low Cost Automated Module Assembly for 180 GHz Devices Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Emergence of Indium Phosphide IC's has made possible devices operating at frequencies up to 200GHZ and beyond. Building modules using these devices opens a goldmine...

  2. Toxicant-induced oxidative stress in cancer.

    Science.gov (United States)

    Upham, B L; Wagner, J G

    2001-11-01

    The article highlighted in this issue is "The Role of Oxidative Stress in Indium Phosphide-Induced Lung Carcinogenesis in Rats" by Barbara C. Gottschling, Robert R. Maronpot, James R. Hailey, Shyamal Peddada, Cindy R. Moomaw, James E. Klaunig, and Abraham Nyska (pp. 28-40). The article integrates a traditional pathologic study of toxicant-induced pulmonary carcinogenesis with an immunohistologic assessment of oxidative stress, thereby determining a potential mechanism of action of a toxicant, specifically indium phosphide.

  3. Surface electronic structure of rare earth metals

    Energy Technology Data Exchange (ETDEWEB)

    Blyth, R.I.R.; Dhesi, S.S.; Gravil, P.A.; Newstead, K.; Cosso, R.; Cole, R.J.; Patchett, A.J.; Mitrelias, T. (Surface Science Research Centre, Univ. of Liverpool (United Kingdom)); Prince, N.P.; Barrett, S.D. (Surface Science Research Centre, Univ. of Liverpool (United Kingdom) Oliver Lodge Lab., Univ. of Liverpool (United Kingdom))

    1992-03-25

    Angle-resolved UV photoemission has been used to investigate the electronic structure of the (0001) surfaces of scandium, yttrium, praseodymium and gadolinium. Off-normal emission spectra were recorded with high angular resolution, enabling detailed mapping of the dispersion of valence band features. Yttrium and gadolinium show similar results to published data from Ho(0001), suggesting minimal 4f influence in the lanthanide bandstructures. Differences seen on praseodymium and scandium may be due to 4f-derived states and surface states respectively. (orig.).

  4. Strained quantum well photovoltaic energy converter

    Science.gov (United States)

    Freundlich, Alexandre (Inventor); Renaud, Philippe (Inventor); Vilela, Mauro Francisco (Inventor); Bensaoula, Abdelhak (Inventor)

    1998-01-01

    An indium phosphide photovoltaic cell is provided where one or more quantum wells are introduced between the conventional p-conductivity and n-conductivity indium phosphide layer. The approach allows the cell to convert the light over a wider range of wavelengths than a conventional single junction cell and in particular convert efficiently transparency losses of the indium phosphide conventional cell. The approach hence may be used to increase the cell current output. A method of fabrication of photovoltaic devices is provided where ternary InAsP and InGaAs alloys are used as well material in the quantum well region and results in an increase of the cell current output.

  5. Physical properties of some noble metal compounds from PAW-DFT ...

    African Journals Online (AJOL)

    The heats of formation, shear modulus, fracture toughness, density and melting points of compounds formed between some noble metals and aluminum, scandium, hafnium and zirconium were evaluated by the ab initio quantum mechanical projector augmented wave (PAW) calculation methods, using the Density ...

  6. Understanding the structure and electronic properties of N-doped ...

    Indian Academy of Sciences (India)

    Structures and electronic properties of zigzag graphene nanoribbon (ZGNR) with pyridine (3NVZGNR) functionalized by Scandium (Sc) at the edge were studied through quantum chemical calculations in the formalism of density-functional theory (DFT). Pyridine-like nitrogen defects is very crucial for enhancing the Sc atom ...

  7. Critical metals (REE, Sc, PGE) in Ni laterites from Cuba and the Dominican Republic

    Czech Academy of Sciences Publication Activity Database

    Aiglsperger, T.; Proenza, J. A.; Lewis, J. F.; Labrador, M.; Svojtka, Martin; Rojas-Purón, A.; Longo, F.; Ďurišová, Jana

    2016-01-01

    Roč. 73, March 01 (2016), s. 127-147 ISSN 0169-1368 Institutional support: RVO:67985831 Keywords : Caribbean * Cuba * Dominican Republic * Falcondo mining area * Moa Bay mining area * Ni laterite * Platinum Group Elements * Rare Earth Elements * Scandium Subject RIV: DB - Geology ; Mineralogy Impact factor: 3.095, year: 2016

  8. Efficient conversion of triacylglycerols and fatty acids to biodiesel in a microwave reactor using metal triflate catalysts.

    Science.gov (United States)

    Socha, Aaron M; Sello, Jason K

    2010-10-21

    We report that catalytic quantities of the Lewis acidic metal catalysts scandium triflate and bismuth triflate promote conversion of oleic, linoleic, palmitic and myristic acids and their glyceryl triesters to the corresponding methyl esters (biodiesel) in greater than 90% yield upon microwave heating. Additionally, both catalysts could be recovered and reused in esterification reactions at least six times.

  9. Effect of structural imperfections on lasing characteristics of diode-pumped YVO{sub 4}, GdVO{sub 4} and mixed rare-earth vanadate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Orlova, G Yu; Vlasov, V I; Zavartsev, Yu D; Zagumennyi, A I; Kalashnikova, I I; Kutovoi, S A; Naumov, V S; Sirotkin, A A

    2012-03-31

    The efficiency of diode-pumped lasers with gain elements made from yttrium, gadolinium, yttrium - gadolinium and yttrium - scandium orthovanadate crystals has been shown for the first time to be influenced by structural imperfections (quality) of the crystals. This allows one to predict lasing parameters of such crystals in a preliminary step, without fabricating gain elements.

  10. Sc-45 nuclear magnetic resonance analysis of precipitation in dilute Al-Sc alloys

    NARCIS (Netherlands)

    Celotto, S; Bastow, TJ

    Nuclear magnetic resonance (NMR) with Sc-45 is used to determine the solid solubility of scandium in aluminium and to follow the precipitation of Al3Sc during the ageing of an Al-0.06 at.% Sc alloy via the two fully resolved peaks, corresponding to Sc in the solid solution Al matrix and to Sc in the

  11. Intercombination lines of AlVIII, AlIX, and AlX ions

    Science.gov (United States)

    Denne, B.; Hinnov, E.

    1984-06-01

    Several aluminum lines observed in the Princeton Large Torus tokamak discharges have been identified as intersystem transitions, establishing the energies of the Al VIII 2s2p35S, Al IX 2s2p24P, and Al X 2s2p3P terms. Some observations of isoelectronic transitions in scandium and titanium ions are also reported.

  12. physical properties of some noble metal compounds from paw-dft ...

    African Journals Online (AJOL)

    PUBLICATIONS1

    ABSTRACT. The heats of formation, shear modulus, fracture toughness, density and melting points of com- pounds formed between some noble metals and aluminum, scandium, hafnium and zirconium were evaluated by the ab initio quantum mechanical projector augmented wave (PAW) calcula- tion methods, using the ...

  13. Surface roughness and morphologic changes of zirconia: Effect of ...

    African Journals Online (AJOL)

    Purpose: The purpose of this study was to investigate the surface roughness and morphologic changes of pre.sintered ZrO2 after sandblasting and erbium, chromium: Yttrium, scandium, gallium, garnet (Er, Cr: YSGG) laser application of different intensities. Material and Methods: Eighty pre-sintered ZrO2 cylinders (7 mm ...

  14. Contamination assessment of toxic elements in the soil within and ...

    African Journals Online (AJOL)

    Scandium, vanadium and strontium were only present in the active dumpsite with minimum enrichment while Lanthanum was present only in the abandoned dumpsite with background enrichment. The geo-accumulation index (Igeo) values for arsenic, chromium, molybdenum, manganese, lanthanum and arsenic, strontium ...

  15. RARE EARTH ELEMENTS: A REVIEW OF PRODUCTION, PROCESSING, RECYCLING, AND ASSOCIATED ENVIRONMENTAL ISSUES

    Science.gov (United States)

    Rare earth elements (REEs) are a group of 15 chemical elements in the periodic table, specifically the lanthanides. Two other elements, scandium and yttrium, have a similar physiochemistry to the lanthanides, are commonly found in the same mineral assemblages, and are often refe...

  16. Faraday isolator based on TSAG crystal for high power lasers.

    Science.gov (United States)

    Mironov, E A; Palashov, O V

    2014-09-22

    A Faraday isolator based on a new magneto-optical medium, TSAG (terbium scandium aluminum garnet) crystal, has been constructed and investigated experimentally. The device provides an isolation ratio of more than 30 dB at 500 W laser power. It is shown that this medium can be used in Faraday isolators for kilowatt-level laser powers.

  17. Neutron-Activation Analysis of Biological Material with High Radiation Levels

    Energy Technology Data Exchange (ETDEWEB)

    Samsahl, K.

    1966-09-15

    A method has been developed for the chemical separation and subsequent gamma-spectrometric analysis of the alkali metals, the alkaline earths, the rare earths, chromium, hafnium, lanthanum, manganese, phosphorus, scandium and silver in neutron-activated biological material. The separation steps, being fully automatic, are based on a combination of ion-exchange and partition chromatography and require 40 min.

  18. Popoola & Bello (12)

    African Journals Online (AJOL)

    big timmy

    The effects of the substitution of aluminum or scandium on the density, toughness as well as the stability of the phases formed by such an addition on platinum, iridium, rhodium and palladium metals were evaluated with the density functional quantum mechanical calculation methods. All the metals had four atoms per ...

  19. Thin film photovoltaic device

    Science.gov (United States)

    Catalano, A.W.; Bhushan, M.

    1982-08-03

    A thin film photovoltaic solar cell which utilizes a zinc phosphide semiconductor is of the homojunction type comprising an n-type conductivity region forming an electrical junction with a p-type region, both regions consisting essentially of the same semiconductor material. The n-type region is formed by treating zinc phosphide with an extrinsic dopant such as magnesium. The semiconductor is formed on a multilayer substrate which acts as an opaque contact. Various transparent contacts may be used, including a thin metal film of the same chemical composition as the n-type dopant or conductive oxides or metal grids. 5 figs.

  20. Effects of two prairie dog rodenticides on ground-dwelling invertebrates in western South Dakota

    Science.gov (United States)

    Michele S. Deisch; Daniel W. Uresk; Raymond L. Linder

    1989-01-01

    Immediate and long-term effects of 3 rodenticide treatments on nontarget invertebrates were evaluated on prairie dog colonies. Immediate impacts indicated zinc phosphide reduced ants, strychnine alone reduced wolf spiders, and prebaited strychnine had no impacts. Long-term changes showed increases in wolf spiders and ground beetles and densities were contributed to...

  1. Nonlinear Optics with a Free-Electron Laser

    NARCIS (Netherlands)

    Eliel, E. R.; van der Ham, E. W. M.; Vrehen, Q. H. F.; Barmentlo, M.; Thooft, G. W.; van der Meer, A. F. G.; van Amersfoort, P. W.

    1994-01-01

    We report on an experiment on spectroscopic infrared-visible Sum-Frequency Generation (SFG) with a Free-Electron Laser (FEL) as the IR-source. The SFG spectrum of gallium phosphide has been investigated in detail in an experiment covering the unsurpassed spectral range from 20 to 32 mum. This

  2. Poultry egg components as cereal bait additives for enhancing rodenticide based control success and trap index of house rat, Rattus rattus

    Directory of Open Access Journals (Sweden)

    Neena Singla

    2014-05-01

    Conclusions: Present data support the use of 2% egg albumin and egg shell powder in cereal bait to enhance acceptance and efficacy of 2% zinc phosphide bait against R. rattus. This may further help in checking the spread of rodent borne diseases to animals and humans.

  3. Development of P/M Fe–P soft magnetic materials

    Indian Academy of Sciences (India)

    Abstract. Phosphorous is treated as an impurity in conventional steels owing to segregation of phosphorous and formation of brittle phosphides along the grain boundaries. It is responsible for cold and hot shortness in wrought steels. In conventional powder metallurgy, involving compaction and sintering, high phosphorous ...

  4. RESONANCEI--O-ct-ob-er

    Indian Academy of Sciences (India)

    poison shyness among rodents which develops after exposure to acute toxicants especially zinc phosphide. The Predatory Myth. Snakes are considered to be the most effective predators of rodents. This appears to be untrue. About 25 species of snakes and two species of monitor lizard, Varanus, occur in the desert.

  5. Phosphorus-based compounds for EUV multilayer optics materials

    NARCIS (Netherlands)

    Medvedev, Viacheslav; Yakshin, Andrey; van de Kruijs, Robbert Wilhelmus Elisabeth; Bijkerk, Frederik

    2015-01-01

    We have evaluated the prospects of phosphorus-based compounds in extreme ultraviolet multilayer optics. Boron phosphide (BP) is suggested to be used as a spacer material in reflective multilayer optics operating just above the L-photoabsorption edge of P (λ ≈9.2 nm). Mo, Ag, Ru, Rh, and Pd were

  6. Spatial Extent of Random Laser Modes

    NARCIS (Netherlands)

    van der Molen, K.L.; Tjerkstra, R.W.; Mosk, Allard; Lagendijk, Aart

    2007-01-01

    We have experimentally studied the distribution of the spatial extent of modes and the crossover from essentially single-mode to distinctly multimode behavior inside a porous gallium phosphide random laser. This system serves as a paragon for random lasers due to its exemplary high index contrast.

  7. Experimental observation of second-harmonic generation and diffusion inside random media

    NARCIS (Netherlands)

    Faez, Sanli; Johnson, P. M.; Mazurenko, D. A.; Lagendijk, Ad

    We have experimentally measured the distribution of the second-harmonic intensity that is generated inside a highly scattering slab of porous gallium phosphide. Two complementary techniques for determining the distribution are used. First, the spatial distribution of second-harmonic light intensity

  8. Large-signal modeling of multi-finger InP DHBT devices at millimeter-wave frequencies

    DEFF Research Database (Denmark)

    Johansen, Tom Keinicke; Midili, Virginio; Squartecchia, Michele

    2017-01-01

    A large-signal modeling approach has been developed for multi-finger devices fabricated in an Indium Phosphide (InP) Double Heterojunction Bipolar Transistor (DHBT) process. The approach utilizes unit-finger device models embedded in a multi-port parasitic network. The unit-finger model is based...

  9. All-optical signal processing at 10 GHz using a photonic crystal molecule

    Energy Technology Data Exchange (ETDEWEB)

    Combrié, Sylvain; Lehoucq, Gaëlle; Junay, Alexandra; De Rossi, Alfredo, E-mail: alfredo.derossi@thalesgroup.com [Thales Research and Technology, 1 Avenue A. Fresnel, 91767 Palaiseau (France); Malaguti, Stefania; Bellanca, Gaetano; Trillo, Stefano [Department of Engineering, Università di Ferrara, v. Saragat 1, 44122 Ferrara (Italy); Ménager, Loic [Thales Systèmes Aeroportés, 2 Av. Gay Lussac, 78851 Elancourt (France); Peter Reithmaier, Johann [Institute of Nanostructure Technologies and Analytics, CINSaT, University of Kassel, Heinrich-Plett-Str. 40, 34132 Kassel (Germany)

    2013-11-04

    We report on 10 GHz operation of an all-optical gate based on an Indium Phosphide Photonic Crystal Molecule. Wavelength conversion and all-optical mixing of microwave signals are demonstrated using the 2 mW output of a mode locked diode laser. The spectral separation of the optical pump and signal is crucial in suppressing optical cross-talk.

  10. Ternary Pd-Ni-P hybrid electrocatalysts derived from Pd-Ni core-shell nanoparticles with enhanced formic acid oxidation activity.

    Science.gov (United States)

    Liang, Xin; Liu, Bo; Zhang, Juntao; Lu, Siqi; Zhuang, Zhongbin

    2016-09-25

    Ternary Pd-Ni-P hybrid electrocatalysts were synthesized through low temperature phosphidation of Pd-Ni core-shell nanoparticles. They show enhanced formic acid electro-oxidation activity compared to Pd, Pd-Ni and Pd-P nanoparticles, which is ascribed to the synergistic effect of the Ni and P components with Pd.

  11. Development of P/M Fe–P soft magnetic materials

    Indian Academy of Sciences (India)

    Phosphorous is treated as an impurity in conventional steels owing to segregation of phosphorous and formation of brittle phosphides along the grain boundaries. It is responsible for cold and hot shortness in wrought steels. In conventional powder metallurgy, involving compaction and sintering, high phosphorous content ...

  12. Monolithically integrated widely tunable laser source operating at 2 μm

    NARCIS (Netherlands)

    Latkowski, S; Hänsel, A.; Van Veldhoven, P. J.; D’Agostino, D.; Rabbani-Haghighi, H.; Docter, B.; Bhattacharya, N.; Thijs, P. J A; Ambrosius, H. P M M; Smit, M; Bente, E.A.J.M.

    2016-01-01

    We present a widely tunable extended cavity ring laser operating at 2 μm that is monolithically integrated on an indium phosphide substrate. The photonic integrated circuit is designed and fabricated within a multiproject wafer run using a generic integration technology platform. The laser

  13. Effect of a nanoparticle on the optical properties of a photonic crystal cavity : Theory and experiment

    NARCIS (Netherlands)

    Van der Sar, T.; Hagemeier, J.; Pfaff, W.; Heeres, E.; Thon, S.; Kim, H.; Petroff, P.; Oosterkamp, T.; Bouwmeester, D.; Hanson, R.

    2012-01-01

    Single quantum emitters can be coupled to photonic crystal (PC) cavities by placing their host nanoparticles into the cavity field. We describe fabrication, characterization, and tuning of gallium-phosphide PC cavities that resonate in the visible, and simulations and measurements of the effect of a

  14. Experimental determination of the effective refractive index in strongly scattering media

    NARCIS (Netherlands)

    Gómez Rivas, J.; Gomez Rivas, J.; Hau, D.H.; Imhof, A.; Sprik, R.; Bret, B.P.J.; Johnson, P.M.; Hijmans, T.W.; Lagendijk, Aart

    2003-01-01

    Measurements of the angular-resolved-optical transmission through strongly scattering samples of porous gallium phosphide are described. Currently porous GaP is the strongest-scattering material for visible light. From these measurements the effective refractive index and the average reflectivity at

  15. On-chip patch antenna on InP substrate for short-range wireless communication at 140 GHz

    DEFF Research Database (Denmark)

    Dong, Yunfeng; Johansen, Tom Keinicke; Zhurbenko, Vitaliy

    2017-01-01

    This paper presents the design of an on-chip patch antenna on indium phosphide (InP) substrate for short-range wireless communication at 140 GHz. The antenna shows a simulated gain of 5.3 dBi with 23% bandwidth at 140 GHz and it can be used for either direct chip-to-chip communication or chip...

  16. Effect of hydrostatic pressure on the structural, elastic and electronic ...

    Indian Academy of Sciences (India)

    In this paper we present the results obtained from first-principles calculations of the effect of hydrostatic pressure on the strucural, elastic and electronic properties of (B3) boron phosphide, using the pseudopotential plane-wave method (PP-PW) based on density functional theory within the Teter and Pade ...

  17. Effect of hydrostatic pressure on the structural, elastic and electronic ...

    Indian Academy of Sciences (India)

    The results showed a phase transition pressure from the zinc blende to rock-salt phase at around 1.56 Mbar, which is in good agreement with the theoretical data reported in the literature. Keywords. Hydrostatic pressure effect; structural, elastic and electronic properties; (B3) boron phosphide. PACS Nos 45.10.Ab; 62.20.

  18. Rague-Like FeP Nanocrystal Assembly on Carbon Cloth: An Exceptionally Efficient and Stable Cathode for Hydrogen Evolution

    KAUST Repository

    Yang, Xiulin

    2015-05-25

    There is a strong demand to replace expensive Pt catalysts with cheap metal sulfides or phosphides for hydrogen generation in water electrolysis. The earth-abundant Fe can be electroplated on carbon cloth (CC) to form high surface area rague-like FeOOH assembly. Subsequent gas phase phosphidation converts the FeOOH to FeP or FeP2 and the morphology of the crystal assembly is controlled by the phosphidation temperature. The FeP prepared at 250 oC presents lower crystallinity and those prepared at higher temperatures 400 oC and 500 oC possess higher crystallinity but lower surface area. The phosphidation at 300 oC produces nanocrystalline FeP and preserves the high-surface area morphology; thus it exhibits the highest HER efficiency in 0.5 M H2SO4; i.e. the required overpotential to reach 10 and 20 mA/cm2 is 34 and 43 mV respectively. These values are lowest among the reported non-precious metal phosphides on CC. The Tafel slope for the FeP prepared at 300 oC is around 29.2 mV/dec comparable to that of Pt/CC, indicating that the hydrogen evolution for our best FeP is limited by Tafel reaction (same as Pt). Importantly, the FeP/CC catalyst exhibits much better stability in a wide range working current density (up to 1 V/cm2), suggesting that it is a promising replacement of Pt for HER.

  19. Degradation Mechanisms of SOFC Anodes in Coal Gas Containing Phosphorus

    Energy Technology Data Exchange (ETDEWEB)

    Marina, Olga A.; Coyle, Christopher A.; Thomsen, Edwin C.; Edwards, Danny J.; Coffey, Greg W.; Pederson, Larry R.

    2010-01-22

    The interaction of phosphorus in synthetic coal gas with the nickel-based anode of solid oxide fuel cells has been investigated. Tests with both anode-supported and electrolyte-supported button cells were performed at 700 to 800oC in synthetic coal gas containing 0.5 to 10 ppm phosphorus, introduced as phosphine. Two primary modes of degradation were observed. The most obvious was the formation of a series of bulk nickel phosphide phases, of which Ni3P, Ni5P2, Ni12P5 and Ni2P were identified. Phosphorus was essentially completely captured by the anode, forming a sharp boundary between converted and unconverted anode portions. These products partially coalesced into large grains, which eventually affected electronic percolation through the anode support. Thermodynamic calculations predict that formation of the first binary nickel phosphide phase is possible at sub-parts per billion concentrations in coal gas at temperatures relevant to fuel cell operation. A second mode of degradation is attributed to surface diffusion of phosphorus to the active anode/electrolyte interface to form an adsorption layer. Direct evidence for the presence of such an adsorption layer on nickel was obtained by surface spectroscopies on fracture surfaces. Further, cell performance losses were observed well before the entire anode was converted to bulk nickel phosphide. Impedance spectroscopy revealed that these losses were primarily due to growth in electrodic resistance, whereas large ohmic increases were visible when the entire anode was converted to nickel phosphide phases. The rate of resistance growth for anode-supported cells showed a very low dependence on phosphorus concentration, attributed to phosphorus activity control within the anode by bulk nickel phosphide products.

  20. The study of inorganic scintillating materials

    Science.gov (United States)

    Dudkin, G. N.; Kuznetsov, S. I.; Padalko, V. N.; Syrtanov, M. S.

    2017-05-01

    The procedure for measuring the temporal characteristics and light output of inorganic scintillating materials excited by β-, γ-, and α-particles from radioactive sources is described. Results of measurements of characteristics are presented for ∼30 scintillating compounds including cerium-doped yttrium silicate and scandium borate; europium-doped strontium phosphate; cerium-doped strontium silicate, calcium silicate and magnesium calcium silicate, etc. Upon β- and γ-excitation, cerium-doped scandium borate gives the highest light output with a fluorescent lifetime of 40 ± 4 ns. The highest light output for α-excitation was from cerium-doped yttrium aluminum perovskite, with a fluorescent lifetime of 29 ± 3 ns.

  1. Synthesis and crystal structure of the first Sc-Nb-O-N phases

    Energy Technology Data Exchange (ETDEWEB)

    Orthmann, Steven; Lerch, Martin [Institut fuer Chemie, Technische Universitaet Berlin (Germany)

    2017-11-17

    Synthesis of phase-pure materials in the system Sc-Nb-O-N is challenging. In this contribution we report on the preparation of the first scandium niobium oxide nitrides via reaction of water-saturated gaseous ammonia or an ammonia-oxygen mixture with amorphous scandium niobium oxides. Two new phases were obtained: rutile-type ScNb{sub 4}O{sub 7}N{sub 3}, which crystallizes in space group P4{sub 2}/mnm, and an anion-deficient fluorite-type Sc{sub 2}Nb(O,N,⬜){sub 6} phase crystallizing in space group Fm anti 3m. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Stress controlled pulsed direct current co-sputtered Al1−xScxN as piezoelectric phase for micromechanical sensor applications

    Directory of Open Access Journals (Sweden)

    Simon Fichtner

    2015-11-01

    Full Text Available Scandium alloyed aluminum nitride (Al1−xScxN thin films were fabricated by reactive pulsed direct current co-sputtering of separate scandium and aluminum targets with x ≤ 0.37. A significant improvement of the clamped transversal piezoelectric response to strain e31,f from −1.28 C/m2 to −3.01 C/m2 was recorded, while dielectric constant and loss angle remain low. Further, the built-in stress level of Al1−xScxN was found to be tuneable by varying pressure, Ar/N2 ratio, and Sc content. The thus resulting enhancement of the expectable signal to noise ratio by a factor of 2.1 and the ability to control built-in stress make the integration of Al1−xScxN as the piezoelectric phase of micro-electro-mechanical system sensor applications highly attractive.

  3. Activated production of silent metabolites from marine-derived fungus Penicillium citrinum.

    Science.gov (United States)

    Gu, Yuqin; Ding, Peiyu; Liang, Zhipeng; Song, Yan; Liu, Yonghong; Chen, Guangtong; Li, Jian Lin

    2018-02-20

    As an attempt to utilize of rare earth elements as a novel method to activate the silent genes in fungus, the marine-derived fungus Penicillium citrinum was cultured under ordinary laboratory fermentation conditions in the presence of scandium chloride (ScCl 3 , 50 μM), and chemical investigation led to the isolation and characterization of three new peptide derivatives (1-3), along with four known pyrrolidine alkaloids (4-7). Those structures were elucidated by spectroscopic data interpretation, as well as chemical reactions. Comparative metabolic profiling of the culture extracts (with/without scandium chloride) indicated that compounds 1-3 scarcely detected in the absence of ScCl 3 . In addition, the antibacterial and cytotoxic activities of all isolated products were evaluated. Copyright © 2017. Published by Elsevier B.V.

  4. Preparation and characterization of Sc doped MgB2 wires

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude; Burdusel, M.

    2016-01-01

    The in-situ technique was used to manufacture scandium (Sc) doped MgB2 wires in a composite Cu–Nb sheath. After reaction at 700 °C, at most 1 at.% Mg was replaced by Sc in the MgB2 phase, without significant influence on its superconducting transition temperature. For higher Sc concentrations in ...... of the precursor powders revealed by DTA measurements than to actual doping. The best performance was obtained in a wire with Mg:Sc = 0.995_0.005 atomic ratio.......The in-situ technique was used to manufacture scandium (Sc) doped MgB2 wires in a composite Cu–Nb sheath. After reaction at 700 °C, at most 1 at.% Mg was replaced by Sc in the MgB2 phase, without significant influence on its superconducting transition temperature. For higher Sc concentrations...

  5. New Volleyballenes: Y20C60, La20C60, and Lu20C60

    OpenAIRE

    Wang, Jing; Liu, Ying

    2015-01-01

    New stable Volleyballenes Y20C60, La20C60, and Lu20C60 molecular clusters have been proposed using first-principles density functional theory studies. In conjunction with recent findings for the scandium system, these findings establish Volleyballene M20C60 molecules as a stable general class of fullerene family. All M20C60 (M=Y, La, and Lu) molecules have Th point group symmetries and relatively large HOMO-LUMO gaps.

  6. Browse Title Index

    African Journals Online (AJOL)

    Items 501 - 550 of 1605 ... Vol 18, No 4 (2015), Effects of edentulism in obstructive sleep apnea syndrome, Abstract PDF. R Okşayan, O Sökücü, M Uyar, T Topçuoğlu. Vol 18, No 2 (2015), Effects of erbium‑and chromium‑doped yttrium scandium gallium garnet and diode lasers on the surfaces of restorative dental materials: A ...

  7. New Volleyballenes: Y20C60 and La20C60

    OpenAIRE

    Jing Wang; Ying Liu

    2016-01-01

    Two new stable Volleyballenes, the Y20C60 and La20C60 molecular clusters, are proposed on the basis of first-principles density functional theory. In conjunction with recent findings for the scandium system, these findings establish Volleyballene M 20C60 molecules as a general class of stable molecules within the fullerene family. Both Y20C60 and La20C60 molecules have T h point group symmetries and relatively large HOMO-LUMO gaps.

  8. Treatment of oral submucous fibrosis with ErCr: YSGG laser

    Directory of Open Access Journals (Sweden)

    Zainab Chaudhary

    2011-01-01

    Full Text Available Oral submucous fibrosis (OSMF is one of the most poorly understood and unsatisfactorily treated diseases. Various medical and surgical treatments have been used but with limited benefits. However, with advent of lasers, oral surgeons are provided with new modality for treating OSMF. This case report highlights the pioneering effort in treating a moderate case of bilateral OSMF with Erbium Chromium Yttrium Scandium Gallium Garnet (ErCr:YSGG laser showing promising result during follow-up.

  9. Annual reports in inorganic and general syntheses 1974

    CERN Document Server

    Niedenzu, Kurt

    1975-01-01

    Annual Reports in Inorganic and General Syntheses-1974 presents an organized annual summary of synthetic developments in inorganic chemistry and its related areas. The book discusses the chemistry of simple and complex metal hydrides of main groups I, II, and III, boron, aluminium, gallium, indium, thallium, silicon, germanium, tin, lead, phosphorus, arsenic, antimony, bismuth, chalcogens, halogens, and pseudohalogens. The text also describes the chemistry of scandium, yttrium, lanthanides, actinides, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, ma

  10. Annual reports in inorganic and general syntheses 1972

    CERN Document Server

    Niedenzu, Kurt

    1973-01-01

    Annual Reports in Inorganic and General Syntheses-1972 presents an organized annual summary of synthetic developments in inorganic chemistry and its related areas. The book discusses alkali and alkaline earth elements, alloys, silver, gold, zinc, cadmium, mercury, boron, aluminum, gallium, indium, thallium, yttrium, scandium, lanthanides, actinides, titanium, zirconium, hafnium, Group V and VI transition elements, manganese, technetium, rhenium, iron, cobalt, nickel, ruthenium, osmium, rhodium, and iridium. The text also describes the chemistry of palladium, platinum, silicon, germanium, tin,

  11. Organization of the Topical Meeting on Tunable Solid State Lasers Held in North Falmouth, Massachusetts on 1-3 May 1989

    Science.gov (United States)

    1989-08-30

    section can be compared to the cross-section obtained for Cr(III) in gallium scandium gadolinium garnet (GSGG) at 756 nm, which is 0.7 Pm 2 [12], and for...p. 34) ME1 Laser Performance of Chromium- Aluminum Doped Forsterite, Horacio R. Verdun, Leonard M. Thomas, Donna M. 11:30 AM (Invited Paper...Chromium- aluminum gaussian Mirrors, G. Cerullo, V. Magni, R. Riva, 0. Svelto, doped forsterite, prepared by laser-heated pedestal growth, Polytechnic U

  12. Metal organic frameworks for gas storage

    KAUST Repository

    Alezi, Dalal

    2016-06-09

    Embodiments provide a method of storing a compound using a metal organic framework (MOF). The method includes contacting one or more MOFs with a fluid and sorbing one or more compounds, such as O2 and CH4. O2 and CH4 can be sorbed simultaneously or in series. The metal organic framework can be an M-soc-MOF, wherein M can include aluminum, iron, gallium, indium, vanadium, chromium, titanium, or scandium.

  13. Arctic deep-water ferromanganese-oxide deposits reflect the unique characteristics of the Arctic Ocean

    Science.gov (United States)

    Hein, James; Konstantinova, Natalia; Mikesell, Mariah; Mizell, Kira; Fitzsimmons, Jessica N.; Lam, Phoebe; Jensen, Laramie T.; Xiang, Yang; Gartman, Amy; Cherkashov, Georgy; Hutchinson, Deborah; Till, Claire P.

    2017-01-01

    Little is known about marine mineral deposits in the Arctic Ocean, an ocean dominated by continental shelf and basins semi-closed to deep-water circulation. Here, we present data for ferromanganese crusts and nodules collected from the Amerasia Arctic Ocean in 2008, 2009, and 2012 (HLY0805, HLY0905, HLY1202). We determined mineral and chemical compositions of the crusts and nodules and the onset of their formation. Water column samples from the GEOTRACES program were analyzed for dissolved and particulate scandium concentrations, an element uniquely enriched in these deposits.The Arctic crusts and nodules are characterized by unique mineral and chemical compositions with atypically high growth rates, detrital contents, Fe/Mn ratios, and low Si/Al ratios, compared to deposits found elsewhere. High detritus reflects erosion of submarine outcrops and North America and Siberia cratons, transport by rivers and glaciers to the sea, and distribution by sea ice, brines, and currents. Uniquely high Fe/Mn ratios are attributed to expansive continental shelves, where diagenetic cycling releases Fe to bottom waters, and density flows transport shelf bottom water to the open Arctic Ocean. Low Mn contents reflect the lack of a mid-water oxygen minimum zone that would act as a reservoir for dissolved Mn. The potential host phases and sources for elements with uniquely high contents are discussed with an emphasis on scandium. Scandium sorption onto Fe oxyhydroxides and Sc-rich detritus account for atypically high scandium contents. The opening of Fram Strait in the Miocene and ventilation of the deep basins initiated Fe-Mn crust growth ∼15 Myr ago.

  14. Treatment of amalgam tattoo with an Er,Cr:YSGG laser.

    Science.gov (United States)

    Yilmaz, Hasan Guney; Bayindir, Hakan; Kusakci-Seker, Basak; Tasar, Simge; Kurtulmus-Yilmaz, Sevcan

    2010-08-01

    Amalgam tattoos are common, asymptomatic, pigmented oral lesions that clinically exist as isolated, blue, gray, or black macules on the gingival, buccal, and alveolar mucosae, the palate, and/or the tongue. In this case report, the successful use of an erbium, chromium-doped:yttrium, scandium, gallium, and garnet laser for the removal of an amalgam tattoo is explained. A 46-year-old man is presented with a half decade history of an amalgam tattoo on his left maxillary premolar-molar gingiva. Depigmentation procedure was performed under topical anesthesia with the use of an erbium, chromium-doped:yttrium, scandium, gallium, and garnet laser at 2 W in the soft tissue pulsed mode for 10 min. The pigmented tissue was completely removed. The de-epithelialization area healed completely on the 10th day after treatment. The period of healing was uneventful. The amalgam tattoo was completely removed with erbium, chromium-doped:yttrium, scandium, gallium, and garnet laser, and the treated area healed without any adverse effect. © 2010 Blackwell Publishing Asia Pty Ltd.

  15. High-Performance Rh 2 P Electrocatalyst for Efficient Water Splitting

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Haohong; Li, Dongguo; Tang, Yan; He, Yang; Ji, Shufang; Wang, Rongyue; Lv, Haifeng; Lopes, Pietro P.; Paulikas, Arvydas P.; Li, Haoyi; Mao, Scott X.; Wang, Chongmin; Markovic, Nenad M.; Li, Jun; Stamenkovic, Vojislav R.; Li, Yadong

    2017-04-05

    Search for active, stable and cost-efficient electrocatalysts for hydrogen production via water splitting could make substantial impact to the energy technologies that do not rely on fossil fuels. Here we report the synthesis of rhodium phosphide electrocatalyst with low metal loading in the form of nanocubes (NCs) dispersed in high surface area carbon (Rh2P/C) by a facile solvo-thermal approach. The Rh2P/C NCs exhibit remarkable performance for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) compared to Rh/C and Pt/C catalysts. The atomic structure of the rhodium phosphide nanocubes was directly observed by annular dark-field scanning transmission electron microscopy (ADF-STEM), which revealed phosphorous-rich outermost atomic layer. Combined experimental and computational studies suggest that surface phosphorous plays crucial role in determining the robust catalyst properties.

  16. Liquid Phase Synthesis of CoP Nanoparticles with High Electrical Conductivity for Advanced Energy Storage

    Directory of Open Access Journals (Sweden)

    Guo-Qun Zhang

    2017-01-01

    Full Text Available Transition metal phosphide alloys possess the metalloid characteristics and superior electrical conductivity and are a kind of high electrical conductive pseudocapacitive materials. Herein, high electrical conductive cobalt phosphide alloys are fabricated through a liquid phase process and a nanoparticles structure with high surface area is obtained. The highest specific capacitance of 286 F g−1 is reached at a current density of 0.5 A g−1. 63.4% of the specific capacitance is retained when the current density increased 16 times and 98.5% of the specific capacitance is maintained after 5000 cycles. The AC//CoP asymmetric supercapacitor also shows a high energy density (21.3 Wh kg−1 and excellent stability (97.8% of the specific capacitance is retained after 5000 cycles. The study provides a new strategy for the construction of high-performance energy storage materials by enhancing their intrinsic electrical conductivity.

  17. Effects of growth temperature and device structure on GaP solar cells grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Vaisman, M.; Tomasulo, S.; Masuda, T.; Lang, J. R.; Faucher, J.; Lee, M. L. [Department of Electrical Engineering, Yale University, New Haven, Connecticut 06511 (United States)

    2015-02-09

    Gallium phosphide (GaP) is an attractive candidate for wide-bandgap solar cell applications, possessing the largest bandgap of the III-arsenide/phosphides without aluminum. However, GaP cells to date have exhibited poor internal quantum efficiency (IQE), even for photons absorbed by direct transitions, motivating improvements in material quality and device structure. In this work, we investigated GaP solar cells grown by molecular beam epitaxy over a range of substrate temperatures, employing a much thinner emitter than in prior work. Higher growth temperatures yielded the best solar cell characteristics, indicative of increased diffusion lengths. Furthermore, the inclusion of an AlGaP window layer improved both open-circuit voltage and short wavelength IQE.

  18. Terminal tungsten pnictide complex formation through pnictaethynolate decarbonylation.

    Science.gov (United States)

    Joost, Maximilian; Transue, Wesley J; Cummins, Christopher C

    2017-09-26

    Tungsten(iv) tetrakis(2,6-diisopropylphenoxide) (1) has been demonstrated to be a competent platform for decarbonylative formation of anionic terminal pnictide complexes upon treatment with pnictaethynolate anions: cyanate, 2-phosphaethynolate, and 2-arsaethynolate. These transformations constitute the first examples of terminal phosphide and arsenide complex formation at a transition metal center from OCP- and OCAs-, respectively. The phosphide and arsenide complexes are also the first to be isolated in a tetragonal, all-oxygen ligand environment. The scalar NMR coupling constants between tungsten-183 and nitrogen-15 or phosphorus-31 have been measured and contextualized using natural bond orbital (NBO) methods in terms of s orbital character in the σ bonding orbital and pnictide lone pair.

  19. Page 1 2. Photoluminescence study of Cu in InP 407 state minima ...

    Indian Academy of Sciences (India)

    Klick C C and Schulman J H 1957 in Solid state physics (eds) F Seitz and B Turnbull (New York: Academic Press).5 p. 100. Pal D and Bose DN 1995a 7th Int, conſ on indium phosphide and related materials, Proc. IPRM, Japan. Pal D and Bose DN 1995b J. Appl. Phys. 7815. Queisser H J and Fuller CS 1966.J. Appl. Phys.

  20. Zinc incorporation via the vapor-liquid-solid mechanism into InP nanowires.

    Science.gov (United States)

    van Weert, Maarten H M; Helman, Ana; van den Einden, Wim; Algra, Rienk E; Verheijen, Marcel A; Borgström, Magnus T; Immink, George; Kelly, John J; Kouwenhoven, Leo P; Bakkers, Erik P A M

    2009-04-08

    We report the incorporation of zinc atoms into vapor-liquid-solid grown indium phosphide nanowires via a gold catalyst particle. We demonstrate this by synthesizing axial pn-junctions, chemically etching them, and fabricating electrical contacts in a vertical configuration. Electrical measurements show clear diode behavior. Control of dopant incorporation is crucial for future applications and will eventually lead to full freedom of design.

  1. Superconductivity theory applied to the periodic table of the elements

    Energy Technology Data Exchange (ETDEWEB)

    Elifritz, T.L. [Information Corporation, Madison, WI (United States)

    1994-12-31

    The modern theory of superconductivity, based upon the BCS to Bose-Einstein transition, is applied to the periodic table of the elements, in order to isolate the essential features of high temperature superconductivity and to predict its occurrence within the periodic table. It is predicted that Sodium-Ammonia, Sodium Zinc Phosphide and Bismuth (I) Iodide are promising materials for experimental explorations of high temperature superconductivity.

  2. Electrical and thermal characterization of single and multi-finger InP DHBTs

    DEFF Research Database (Denmark)

    Midili, Virginio; Nodjiadjim, V.; Johansen, Tom Keinicke

    2015-01-01

    This paper presents the characterization of single and multi-finger Indium Phosphide Double Heterojunction Bipolar transistors (InP DHBTs). It is used as the starting point for technology optimization. Safe Operating Area (SOA) and small signal AC parameters are investigated along with thermal...... characteristics. The results are presented comparing different device dimensions and number of fingers. This work gives directions towards further optimization of geometrical parameters and reduction of thermal effects....

  3. Superconductivity theory applied to the periodic table of the elements

    Science.gov (United States)

    Elifritz, Thomas Lee

    1995-01-01

    The modern theory of superconductivity, based upon the BCS to Bose-Einstein transition is applied to the periodic table of the elements, in order to isolate the essential features of of high temperature superconductivity and to predict its occurrence with the periodic table. It is predicted that Sodium-Ammonia, Sodium Zinc Phosphide and Bismuth (I) Iodide are promising materials for experimental explorations of high temperature superconductivity.

  4. 40 CFR 372.65 - Chemicals and chemical categories to which this part applies.

    Science.gov (United States)

    2010-07-01

    ... and the unreacted ore component of the chromite ore processing residue (COPR). COPR is the solid waste... Allyl chloride 107-05-1 1/1/87 Aluminum (fume or dust) 7429-90-5 1/1/87 Aluminum oxide (fibrous forms) 1344-28-1 1/1/87 Aluminum phosphide 20859-73-8 1/1/95 Ametryn (N-Ethyl-N′-(1-methylethyl)-6-(methylthio...

  5. Applied solid state science advances in materials and device research

    CERN Document Server

    Wolfe, Raymond

    2013-01-01

    Applied Solid State Science: Advances in Materials and Device Research, Volume 1 presents articles about junction electroluminescence; metal-insulator-semiconductor (MIS) physics; ion implantation in semiconductors; and electron transport through insulating thin films. The book describes the basic physics of carrier injection; energy transfer and recombination mechanisms; state of the art efficiencies; and future prospects for light emitting diodes. The text then discusses solid state spectroscopy, which is the pair spectra observed in gallium phosphide photoluminescence. The extensive studies

  6. NREL Spurred the Success of Multijunction Solar Cells (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2013-08-01

    Many scientists once believed that high-quality gallium indium phosphide (GaInP) alloys could not be grown for use as semiconductors because the alloys would separate. However, researchers at the National Renewable Energy Laboratory (NREL) thought differently, and they employed GaInP in a material combination that allowed the multijunction cell to flourish. The multijunction cell is now the workhorse that powers satellites and the catalyst for renewed interest in concentrator photovoltaic products.

  7. Synergies Connecting the Photovoltaics and Solid-State Lighting Industries

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, S.

    2003-05-01

    Recent increases in the efficiencies of phosphide, nitride, and organic light-emitting diodes (LEDs) inspire a vision of a revolution in lighting. If high efficiencies, long lifetimes, and low cost can be achieved, solid-state lighting could save our country many quads of electricity in the coming years. The solid-state lighting (SSL) and photovoltaic (PV) industries share many of the same challenges. This paper explores the similarities between the two industries and how they might benefit by sharing information.

  8. An Effective Pd–Ni2P/C Anode Catalyst for Direct Formic Acid Fuel Cells

    OpenAIRE

    Chang, Jinfa; Feng, Ligang; Liu, Changpeng; Xing, Wei; Hu, Xile

    2014-01-01

    The direct formic acid fuel cell is an emerging energy conversion device for which palladium is considered as the state-of-the-art anode catalyst. In this communication, we show that the activity and stability of palladium for formic acid oxidation can be significantly enhanced using nickel phosphide (Ni2P) nanoparticles as a cocatalyst. X-ray photoelectron spectroscopy (XPS) reveals a strong electronic interaction between Ni2P and Pd. A direct formic acid fuel cell incorporating the best Pd-...

  9. Photonic crystal Fano resonances for realizing optical switches, lasers and non-reciprocal elements

    DEFF Research Database (Denmark)

    Bekele, Dagmawi Alemayehu; Yu, Yi; Hu, Hao

    2017-01-01

    structure in combination with cavity-enhanced nonlinearity can be used to realize non-reciprocal transmission at ultra-low power and with large bandwidth. A novel type of laser structure, denoted a Fano laser, is discussed in which one of the mirrors is based on a Fano resonance. Finally, the design......, fabrication and characterization of grating couplers for efficient light coupling in and out of the indium phosphide photonic crystal platform is discussed....

  10. Manhattan Project Technical Series The Chemistry of Uranium (I) Chapters 1-10

    Energy Technology Data Exchange (ETDEWEB)

    Rabinowitch, E. I. [Argonne National Laboratory (ANL), Argonne, IL (United States); Katz, J. J. [Argonne National Laboratory (ANL), Argonne, IL (United States)

    1946-09-30

    This constitutes Chapters 1 through 10. inclusive, of The Survey Volume on Uranium Chemistry prepared for the Manhattan Project Technical Series. Chapters are titled: Nuclear Properties of Uranium; Properties of the Uranium Atom; Uranium in Nature; Extraction of Uranium from Ores and Preparation of Uranium Metal; Physical Properties of Uranium Metal; Chemical Properties of Uranium Metal; Intermetallic Compounds and Alloy systems of Uranium; the Uranium-Hydrogen System; Uranium Borides, Carbides, and Silicides; Uranium Nitrides, Phosphides, Arsenides, and Antimonides.

  11. Thermophysical Properties of Matter - The TPRC Data Series. Volume 4. Specific Heat - Metallic Elements and Alloys

    Science.gov (United States)

    1971-01-01

    Aluminum trifluoride (AIF3) Aluminum nitride (A1N) Aluminum nxide (AUOj) Aluminum phosphide (AIP) Page 113 117 293 B93 699 702 705 708...steel (Group II), U-8 Cassiopeium (see Lutetium) Celtium(see Hafnium) Cerium Cerium trifluoride (CeF^) Cerium oxides: CeO Ce203 Cerium dioxide...Cusium monohydrogen difluoride (CsHF2) Cesium iodide (Csl) Chlorine Chlorodifluoromethane (see Freon 22) Chlorotrifluoromethane (see Freon 13

  12. CoP nanosheet assembly grown on carbon cloth: A highly efficient electrocatalyst for hydrogen generation

    KAUST Repository

    Yang, Xiulin

    2015-07-01

    There exists a strong demand to replace expensive noble metal catalysts with cheap metal sulfides or phosphides for hydrogen evolution reaction (HER). Recently metal phosphides such as NixP, FeP and CoP have been considered as promising candidates to replace Pt cathodes. Here we report that the nanocrystalline CoP nanosheet assembly on carbon cloth can be formed by a two-step process: electrochemical deposition of Co species followed by gas phase phosphidation. The CoP catalyst in this report exhibits a Tafel slope of 30.1mV/dec in 0.5M H2SO4 and 42.6mV/dec in 1M KOH. The high HER performance of our CoP catalysts is attributed to the rugae-like morphology which results in a high double-layer capacitance and high density of active sites, estimated as 7.77×1017sites/cm2. © 2015 Elsevier Ltd.

  13. In-situ FTIR reflection spectroscopy for the semiconductor electrolyte interfaces

    Science.gov (United States)

    Chandrasekaran, K.; Bockris, J. O'M.

    1986-10-01

    Polarization modulation fourier transform infrared reflection-absorption spectroscopy (FTIR-RAS) and subtractively normalized interfacial fourier transform infrared spectroscopy (SNIF-TIRS) have been applied to the studies of adsorption of ions and neutral molecules on p-silicon and p-gallium phosphide electrodes in aqueous as well as non-aqueous solutions. The potential and concentration dependence of adsorption were observed. Thiourea is adsorbed on silicon through the sulfur atom and adsorption increases in the anodic direction. Thiourea adsorption on silicon follows a Temkin type isotherm and the free energy adsorption was calculated to be - 5.63 kJ/mole. Acetate in aqueous medium is adsorbed as neutral acetic acid molecule on silicon. The potential dependence of adsorption passes through a maximum which lies close to the potential of zero charge. The tetraethylammonium ion in acetonitrile is adsorbed according to a Langmuir isotherm. Acetonitrile is adsorbed strongly on gallium phosphide when used as a solvent for sodium acetate at cathodic potentials. At anodic potentials adsorbed acetonitrile is replaced by acetate ions. Adsorption of acetate ion starts at potentials cathodic to the potential of zero charge, due to specific adsorption. Ammonium ion adsorption on gallium phosphide occurs through two hydrogen atoms and the other two hydrogen atoms project towards the solution. Two peaks corresponding to different N-H deformation vibrations are observed at 1560 and 1700 cm -1. At sufficiently cathodic potentials, adsorbed ammonium ions are reduced.

  14. Ab initio investigations of the electronic structures and chemical bonding in LiCo{sub 6}P{sub 4} and Li{sub 2}Co{sub 12}P{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Matar, Samir F. [CNRS, ICMCB, UPR 9048, F‐33600 Pessac (France); Université de Bordeaux, ICMCB, UPR 9048, F‐33600 Pessac (France); Al-Alam, Adel; Ouaini, Naïm [Université Saint-Esprit de Kaslik (USEK), Groupe OCM (Optimization et Caractérisation des Matériaux), CSR-USEK, CNRS-L, Jounieh (Lebanon); Pöttgen, Rainer, E-mail: pottgen@uni-muenster.de [Institut für Anorganische und Analytische Chemie, Universität Münster, Corrensstraße 30, D-48149 Münster (Germany)

    2013-06-15

    The electronic structures of the metal-rich phosphides LiCo{sub 6}P{sub 4} and Li{sub 2}Co{sub 12}P{sub 7} were studied by DFT calculations. Both phosphides consist of three-dimensional [Co{sub 6}P{sub 4}] and [Co{sub 12}P{sub 7}] polyanionic networks which leave hexagonal channels for the lithium atoms. COOP data show strong Co–P and Co–Co bonding within the polyanions. The lithium atoms have trigonal prismatic phosphorus coordination. Total energy calculations indicate stability upon de-lithiation towards the Co{sub 6}P{sub 4} and Co{sub 12}P{sub 7} substructures - Graphical abstract: The cobalt–phosphorus networks in LiCo{sub 6}P{sub 4} and Li{sub 2}Co{sub 12}P{sub 7}. - Highlights: • Chemical bonding resolved in the metal-rich phosphides LiCo{sub 6}P{sub 4} and Li{sub 2}Co{sub 12}P{sub 7}. • Strong covalent Co–P bonding character in the [Co{sub 6}P{sub 4}] and [Co{sub 12}P{sub 7}] substructures. • Total energy calculations indicate stability of the de-lithiated substructures.

  15. Porphyrinic Metal-Organic Framework-Templated Fe-Ni-P/Reduced Graphene Oxide for Efficient Electrocatalytic Oxygen Evolution.

    Science.gov (United States)

    Fang, Xinzuo; Jiao, Long; Zhang, Rui; Jiang, Hai-Long

    2017-07-19

    The sluggish kinetics of oxygen evolution reaction (OER) hampers the H2 production by H2O electrolysis, and it is very important for the development of highly efficient and low-priced OER catalysts. Herein, a representative metalloporphyrinic MOF, PCN-600-Ni, integrated with graphene oxide (GO), serves as an ideal precursor and template to afford bimetallic iron-nickel phosphide/reduced graphene oxide composite (denoted as Fe-Ni-P/rGO-T; T represents pyrolysis temperature) via pyrolysis and subsequent phosphidation process. Thanks to the highly porous structure, the synergetic effect of Fe and Ni elements in bimetallic phosphide, and the good conductivity endowed by rGO, the optimized Fe-Ni-P/rGO-400 exhibits remarkable OER activity in 1 M KOH solution, affording an extremely low overpotential of 240 mV at 10 mA/cm2, which is far superior to the commercial IrO2 and among the best in all non-noble metal-based electrocatalysts.

  16. Recent developments in production of radioactive ion beams with the selective laser ion source at the on-line isotope separator ISOLDE

    CERN Document Server

    Catherall, Richard; Köster, U; Lettry, Jacques; Suberlucq, Guy; Marsh, Bruce A; Tengborn, Elisabeth

    2004-01-01

    The production of radioactive ionization laser ion source (RILIS) of ISOLDE on-line isotope separation facility was investigated. The RILIS setup included three dye lasers and ionization schemes which employ three resonant transitions were also used. The RILIS efficiency could be reduced by nuclear effects such as hyperfine splitting and isotope shifts. The off-line resonance ionization spectroscopy determined optimal three-step ionization schemes for yttrium, scandium and antimony and antimony. The results show that best ionization schemes of Y provided gain factor of 15 with respect to surface ionization. (Edited abstract) 8 Refs.

  17. 1.0. B. Ewa

    African Journals Online (AJOL)

    Lanthanum Lit-140 487,1596.5 26.46(0.02). Lutetium Lu-177 208.4 0.59(0.01). Neodymium Nd-147 91,531 20.21(5.91). Potassium(%)K-42 1524.7 1.46(0,0]). Rubidium Rb—86 1076.6 71.66(2.11). 112.33Scandium Sc-46 889.3,1120.3. Sodium(%)Na-24 1368.5 0.01(1.0E-04). Tantalum Til—182 1221.4 2.12(0.07). Thorium ...

  18. Stress and strain effects on the electronic structure and optical properties of ScN monolayer

    Science.gov (United States)

    Tamleh, Shirin; Rezaei, Ghasem; Jalilian, Jaafar

    2018-02-01

    Based on the density functional theory, electronic and optical properties of a monolayer scandium nitride structure have been studied under different strain conditions. Our results indicate that both biaxial compressive and tensile strain effects lead to change the band gap of this structure with different rates. Also, optical absorption spectrum peaks experience an obvious red and blue shifts with the exerting of tensile and compressive strains, respectively. Our results express that ScN monolayer can be the promising candidate for the future nano-base electrical and optical devices.

  19. Renormalized molecular levels in a Sc3N@C-80 molecular electronic device

    DEFF Research Database (Denmark)

    Larade, Brian; Taylor, Jeremy Philip; Zheng, Q. R.

    2001-01-01

    We address several general questions about quantum transport through molecular systems by an ab initio analysis of a scandium-nitrogen doped C-80 metallofullerene device. Charge transfer from the Sc3N is found to drastically change the current-voltage characteristics: the current through the Sc3N...... @ C-80 device is double that through a bare C-80 device. We provide strong evidence that transport in such molecular devices is mediated by molecular electronic states which have been renormalized by the device environment, such as the electrodes and external bias V-b. The renormalized molecular...

  20. Trace-element contents of postorogenic granites of the eastern Arabian Shield, Kingdom of Saudi Arabia

    Science.gov (United States)

    Stuckless, J.S.; Vaughn, R.B.; VanTrump, George

    1986-01-01

    Trace-element contents for 46 postorogenic granitoids vary by as much as two orders of magnitude; most samples are strongly enriched in incompatible elements (such as the heavy rare earths, yttrium, niobium, and uranium) and depleted in the compatible elements (such as barium, strontium, scandium, europium, and cobalt). These trace-element characteristics are typical of A-type granites found in other areas of the world. In spite of the wide range in trace-element contents, no samples contained economically significant concentrations of a single element.

  1. Very high efficacy electrodeless high intensity discharge lamps

    Science.gov (United States)

    Johnson, Peter D.

    1987-01-01

    An electrodeless arc lamp comprises an outer jacket hermetically sealing and thermally protecting an arc tube inside which has an upwardly convex bottom center section. The absence of chemically reactive electrode material makes it possible to use metal halides other than iodides. The tube contains chlorides, bromides or a mixture thereof of scandium and sodium in a nearly equimolar relationship in addition to mercury and an inert gas. Good color balance can be obtained at reduced reservoir temperature and with less power loss. Reduction in wall temperature makes it possible to attain longer lamp life.

  2. HTSC, negative U, and RVB; cuprates and oxyhalides

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, J.A. (Univ. of Bristol (United Kingdom))

    1994-06-01

    Attention is redrawn to published work on a negative U perception of how HTSC develops in the mixed-valent cuprates and bismuthates. The mechanism that has been proposed is one of a two-subsystem, three-center, dynamic seeded disproportionation, driven by strong shell-closure effects in high-valent environment. In pursuing why alternative proposals seem less viable we have made an examination of the oxyhalide systems TiOCl(Br) substituted with scandium. These d[sup 1] oxyhalides are prime candidates for RVB behavior, though not, it seems, superconductivity. 12 refs.

  3. Accumulation of rare earth elements by siderophore-forming Arthrobacter luteolus isolated from rare earth environment of Chavara, India.

    Science.gov (United States)

    Emmanuel, E S Challaraj; Ananthi, T; Anandkumar, B; Maruthamuthu, S

    2012-03-01

    In this study, Arthrobacter luteolus, isolated from rare earth environment of Chavara (Quilon district, Kerala, India), were found to produce catechol-type siderophores. The bacterial strain accumulated rare earth elements such as samarium and scandium. The siderophores may play a role in the accumulation of rare earth elements. Catecholate siderophore and low-molecular-weight organic acids were found to be present in experiments with Arthrobacter luteolus. The influence of siderophore on the accumulation of rare earth elements by bacteria has been extensively discussed.

  4. Faraday rotator based on TSAG crystal with orientation.

    Science.gov (United States)

    Yasuhara, Ryo; Snetkov, Ilya; Starobor, Aleksey; Mironov, Evgeniy; Palashov, Oleg

    2016-07-11

    A Faraday isolator (FI) for high-power lasers with kilowatt-level average power and 1-µm wavelength was demonstrated using a terbium scandium aluminum garnet (TSAG) with its crystal axis aligned in the direction. Furthermore, no compensation scheme for thermally induced depolarization in a magnetic field was used. An isolation ratio of 35.4 dB (depolarization ratio γ of 2.9 × 10-4) was experimentally observed at a maximum laser power of 1470 W. This result for room-temperature FIs is the best reported, and provides a simple, practical solution for achieving optical isolation in high-power laser systems.

  5. Tri-material multilayer coatings with high reflectivity and wide bandwidth for 25 to 50 nm extreme ultraviolet light

    Energy Technology Data Exchange (ETDEWEB)

    Aquila, Andrew; Salmassi, Farhad; Liu, Yanwei; Gullikson, Eric M.

    2009-09-09

    Magnesium/silicon carbide (Mg/SiC) multilayers have been fabricated with normal incidence reflectivity in the vicinity of 40% to 50% for wavelengths in the 25 to 50 nm wavelength range. However many applications, for example solar telescopes and ultrafast studies using high harmonic generation sources, desire larger bandwidths than provided by high reflectivity Mg/SiC multilayers. We investigate introducing a third material, Scandium, to create a tri-material Mg/Sc/SiC multilayer allowing an increase the bandwidth while maintaining high reflectivity.

  6. Hierarchical MoS2@MoP core-shell heterojunction electrocatalysts for efficient hydrogen evolution reaction over a broad pH range

    Science.gov (United States)

    Wu, Aiping; Tian, Chungui; Yan, Haijing; Jiao, Yanqing; Yan, Qing; Yang, Guoyu; Fu, Honggang

    2016-05-01

    A low-cost catalyst for the hydrogen evolution reaction (HER) over a broad pH range is highly desired to meet the practical needs in different areas. In this study, hierarchical flower-like MoS2@MoP core-shell heterojunctions (HF-MoSP) are designed as a promising catalyst for HER over a broad pH range. The materials are obtained by the controllable phosphidation of the hierarchical MoS2 flower (HF-MoS2) composed of thin silk belt-like sheets. The phosphidation degree, P/S ratio and work function (WF) of HF-MoSP can be tuned easily over broad range by changing the phosphidation temperature. Under optimized condition, HF-MoSP exhibits excellent electrocatalytic activity for HER with a low onset overpotential of 29 mV and η of 108 mV at 10 mA cm-2 in 0.5 M H2SO4 and retains its good activity for 30 h. In addition, the catalyst shows excellent activity in 1 M KOH with an onset overpotential of 42 mV and η of 119 mV at 10 mA cm-2. The catalysts also exhibit obvious activity in neutral, weak acid and weak alkaline conditions. The good performance is relative to the synergy of the MoP shell and MoS2 core and the high WF of HF-MoSP close to Pt, and the large SBET of HF-MoSP benefited from the hierarchical structure. This study represents the construction of the core-shell heterojunction and provides a new way to provide the low-cost and high-performance catalyst for HER.A low-cost catalyst for the hydrogen evolution reaction (HER) over a broad pH range is highly desired to meet the practical needs in different areas. In this study, hierarchical flower-like MoS2@MoP core-shell heterojunctions (HF-MoSP) are designed as a promising catalyst for HER over a broad pH range. The materials are obtained by the controllable phosphidation of the hierarchical MoS2 flower (HF-MoS2) composed of thin silk belt-like sheets. The phosphidation degree, P/S ratio and work function (WF) of HF-MoSP can be tuned easily over broad range by changing the phosphidation temperature. Under optimized

  7. Preparation and characterization of Sc doped MgB{sub 2} wires

    Energy Technology Data Exchange (ETDEWEB)

    Grivel, J.-C., E-mail: jean@dtu.dk [Department of Energy Conversion and Storage, Technical University of Denmark, 4000-Roskilde (Denmark); Burdusel, M. [Faculty of Materials Science and Engineering, Polytechnical University of Bucharest, 060042-Bucharest (Romania)

    2016-09-15

    Highlights: • MgB{sub 2} wires doped with Sc (scandium) were prepared by the in-situ route. • The solubility of Sc in the MgB{sub 2} lattice under the present conditions is negligible. • J{sub c} and B{sup *} are slightly improved for low doping levels. - Abstract: The in-situ technique was used to manufacture scandium (Sc) doped MgB{sub 2} wires in a composite Cu–Nb sheath. After reaction at 700 °C, at most 1 at.% Mg was replaced by Sc in the MgB{sub 2} phase, without significant influence on its superconducting transition temperature. For higher Sc concentrations in the nominal composition, the formation of Sc–rich impurity phases was evidenced by SEM/EDS observations. The critical current density and accommodation field of the wires are weakly dependant on the Sc content. It is believed that these effects are related more to modifications of the thermal behaviour of the precursor powders revealed by DTA measurements than to actual doping. The best performance was obtained in a wire with Mg:Sc = 0.995-0.005 atomic ratio.

  8. Electron spin resonance studies of Bi1-xScxFeO3 nanoparticulates: Observation of an enhanced spin canting over a large temperature range

    Science.gov (United States)

    Titus, S.; Balakumar, S.; Sakar, M.; Das, J.; Srinivasu, V. V.

    2017-12-01

    Bi1-xScxFeO3 (x = 0.0, 0.1, 0.15, 0.25) nano particles were synthesized by sol gel method. We then probed the spin system in these nano particles using electron spin resonance technique. Our ESR results strongly suggest the scenario of modified spin canted structures. Spin canting parameter Δg/g as a function of temperature for Scandium doped BFO is qualitatively different from undoped BFO. A broad peak is observed for all the Scandium doped BFO samples and an enhanced spin canting over a large temperature range (75-210 K) in the case of x = 0.15 doping. We also showed that the asymmetry parameter and thereby the magneto-crystalline anisotropy in these BSFO nanoparticles show peaks around 230 K for (x = 0.10 and 0.15) and beyond 300 K for x = 0.25 system. Thus, we established that the Sc doping significantly modifies the spin canting and magneto crystalline anisotropy in the BFO system.

  9. Responses of Trace Elements to Aerobic Maximal Exercise in Elite Sportsmen

    Science.gov (United States)

    OTAĞ, Aynur; HAZAR, Muhsin; OTAĞ, İlhan; Gürkan, Alper Cenk; Okan, İlyas

    2014-01-01

    Trace elements are chemical elements needed in minute quantities for the proper growth, development, and physiology of the organism. In biochemistry, a trace element is also referred to as a micronutrient. Trace elements, such as nickel, cadmium, aluminum, silver, chromium, molybdenum, germanium, tin, titanium, tungsten, scandium, are found naturally in the environment and human exposure derives from a variety of sources, including air, drinking water and food. The Purpose of this study was investigated the effect of aerobic maximal intensity endurance exercise on serum trace elements as well-trained individuals of 28 wrestlers (age (year) 19.64±1.13, weight (Kg) 70.07 ± 15.69, height (cm) 176.97 ± 6.69) during and after a 2000 meter Ergometer test protocol was used to perform aerobic (75 %) maximal endurance exercise. Trace element serum levels were analyzed from blood samples taken before, immediately after and one hour after the exercise. While an increase was detected in Chromium (Cr), Nickel (Ni), Molybdenum (Mo) and Titanium (Ti) serum levels immediately after the exercise, a decrease was detected in Aluminum (Al), Scandium (Sc) and Tungsten (W) serum levels. Except for aluminum, the trace elements we worked on showed statistically meaningful responses (Ptrace elements to the exercise showed us the selection and application of the convenient sport is important not only in terms of sportsman performance but also in terms of future healthy life plans and clinically. PMID:24762350

  10. Stress controlled pulsed direct current co-sputtered Al{sub 1−x}Sc{sub x}N as piezoelectric phase for micromechanical sensor applications

    Energy Technology Data Exchange (ETDEWEB)

    Fichtner, Simon, E-mail: sif@tf.uni-kiel.de [Institute of Material Science, Christian-Albrechts-Universität, Kaiserstr. 2, 24143 Kiel (Germany); Reimer, Tim; Chemnitz, Steffen; Wagner, Bernhard [Institute of Material Science, Christian-Albrechts-Universität, Kaiserstr. 2, 24143 Kiel (Germany); Fraunhofer Institute for Silicon Technology, Fraunhoferstr. 1, 25524 Itzehoe (Germany); Lofink, Fabian [Fraunhofer Institute for Silicon Technology, Fraunhoferstr. 1, 25524 Itzehoe (Germany)

    2015-11-01

    Scandium alloyed aluminum nitride (Al{sub 1−x}Sc{sub x}N) thin films were fabricated by reactive pulsed direct current co-sputtering of separate scandium and aluminum targets with x ≤ 0.37. A significant improvement of the clamped transversal piezoelectric response to strain e{sub 31,f} from −1.28 C/m{sup 2} to −3.01 C/m{sup 2} was recorded, while dielectric constant and loss angle remain low. Further, the built-in stress level of Al{sub 1−x}Sc{sub x}N was found to be tuneable by varying pressure, Ar/N{sub 2} ratio, and Sc content. The thus resulting enhancement of the expectable signal to noise ratio by a factor of 2.1 and the ability to control built-in stress make the integration of Al{sub 1−x}Sc{sub x}N as the piezoelectric phase of micro-electro-mechanical system sensor applications highly attractive.

  11. High performance AlScN thin film based surface acoustic wave devices with large electromechanical coupling coefficient

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wenbo; He, Xingli; Ye, Zhi, E-mail: yezhi@zju.edu.cn, E-mail: jl2@bolton.ac.uk; Wang, Xiaozhi [Department of Information Science and Electronic Engineering, Zhejiang University and Cyrus Tang Centre for Sensor Materials and Applications, 38 Zheda Road, Hangzhou 310027 (China); Mayrhofer, Patrick M.; Gillinger, Manuel; Bittner, Achim; Schmid, Ulrich [Institute of Sensor and Actuator Systems, Vienna University of Technology, Floragasse, 7/2/366-MST, A-1040 Vienna (Austria); Luo, J. K., E-mail: yezhi@zju.edu.cn, E-mail: jl2@bolton.ac.uk [Institute of Renewable Energy Environmental Technology, University of Bolton, Deane Road, Bolton BL3 5AB (United Kingdom); Department of Information Science and Electronic Engineering, Zhejiang University and Cyrus Tang Centre for Sensor Materials and Applications, 38 Zheda Road, Hangzhou 310027 (China)

    2014-09-29

    AlN and AlScN thin films with 27% scandium (Sc) were synthesized by DC magnetron sputtering deposition and used to fabricate surface acoustic wave (SAW) devices. Compared with AlN-based devices, the AlScN SAW devices exhibit much better transmission properties. Scandium doping results in electromechanical coupling coefficient, K{sup 2}, in the range of 2.0% ∼ 2.2% for a wide normalized thickness range, more than a 300% increase compared to that of AlN-based SAW devices, thus demonstrating the potential applications of AlScN in high frequency resonators, sensors, and high efficiency energy harvesting devices. The coupling coefficients of the present AlScN based SAW devices are much higher than that of the theoretical calculation based on some assumptions for AlScN piezoelectric material properties, implying there is a need for in-depth investigations on the material properties of AlScN.

  12. Effect of Sc/Zr ratio on the microstructure and mechanical properties of new type of Al–Zn–Mg–Sc–Zr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Li, Gen [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Zhao, Naiqin, E-mail: nqzhao@tju.edu.cn [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Liu, Tao [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Li, Jiajun; He, Chunnian; Shi, Chunsheng; Liu, Enzuo [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Sha, Junwei [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)

    2014-11-03

    The rare earth scandium (Sc) as a microalloying element has attracted an increasing interest in aluminum alloys for achieving excellent mechanical properties. Combining with zirconium, high strength and low price Al–Sc alloys are expected. The effects of Sc and Zr on the grain refinement, recrystallization resistance and precipitation hardening were investigated in new type of Al–Zn–Mg–Sc–Zr alloys by rolling, annealing and aging processes. Scandium addition into the Al–Zn–Mg alloys can efficiently refine the grain size and increase recrystallization resistance, especially together with zirconium addition. The maximum value of the yield-to-tensile strength (627 MPa/667 MPa) was obtained with 0.2Sc/0.4Zr ratio of the alloy after solution-aging treatment. The additional strengthening of the alloys is attributed to the grain refinement and the precipitation-strengthening effect of Al{sub 3}Sc, Al{sub 3}Zr or Al{sub 3}(Sc, Zr) in the proper ratio of Sc/Zr during aging.

  13. Changes in thermal plasticity of low grade coals during selective extraction of metals

    Directory of Open Access Journals (Sweden)

    В. Ю. Бажин

    2016-08-01

    Full Text Available As the world oil market tends to be highly volatile, the coal becomes a primary source of organic raw materials for chemical and metallurgical industries. Fossil coals can accumulate high amounts of elements and mixtures quite often reaching commercially valuable concentrations. Reserves of scandium and other rare elements in coal deposits in Siberia alone are sufficient to satisfy the expected global demand for several decades. This study is intended to solve complex tasks associated with extraction of metal oxides using the developed enrichment method to ensure the required thermal plasticity determining the quality and properties of metallurgical coke.Laboratory experiments have been conducted for the enrichment of high-ash coals containing the highest concentrations of metals. Thermal plasticity values have been determined with the help of Gieseler plastometer . Using modern technologies and equipment individual deposits can be turned into profitable production of enriched coking coals with concurrent extraction of rare metals. It has been proven that the highest commercial potential lies with the extraction of scandium and some other rare metals in the form of oxides from the coal.

  14. A compact sup 3 H(p,gamma) sup 4 He 19.8 MeV gamma-ray source for energy calibration at the Sudbury Neutrino Observatory

    CERN Document Server

    Poon, A W P; Waltham, C E; Browne, M C; Robertson, R G H; Kherani, N P; Mak, H B

    2000-01-01

    The Sudbury Neutrino Observatory (SNO) is a new 1000-t D sub 2 O Cherenkov solar neutrino detector. A high-energy gamma-ray source is needed to calibrate SNO beyond the sup 8 B solar neutrino endpoint of 15 MeV. This paper describes the design and construction of a source that generates 19.8 MeV gamma rays using the sup 3 H(p,gamma) sup 4 He reaction (''pT''), and demonstrates that the source meets all the physical, operational and lifetime requirements for calibrating SNO. An ion source was built into this unit to generate and to accelerate protons up to 30 keV, and a high-purity scandium tritide target with a scandium-tritium atomic ratio of 1 : 2.0+-0.2 was included. This pT source is the first self-contained, compact, and portable high-energy gamma-ray source (E subgamma>10 MeV). (authors)

  15. Pulpal thermal responses to an erbium,chromium: YSGG pulsed laser hydrokinetic system.

    Science.gov (United States)

    Rizoiu, I; Kohanghadosh, F; Kimmel, A I; Eversole, L R

    1998-08-01

    Laser systems are known to raise pulpal temperatures when applied to tooth surfaces. Dental biocalcified tissues can be cut with an erbium,chromium:yttrium-scandium-gallium-garnet laser-powered hydrokinetic system. This device is effective for caries removal and cavity preparation in vitro. Pulpal monitoring of temperature changes during hard tissue cutting by a hydrokinetic system have not been reported. This study compared the effects of hydrokinetic system, dry bur, and wet bur tooth cutting on pulpal temperature. In vivo thermocouple intrapulpal measurements were made on cuspid teeth in anesthetized beagle dogs. In vitro measurements were made on extracted human molar teeth preserved in high-salt solution and later rinsed in phosphate-buffered saline (pH 7.4) to simulate in vivo conditions. The hydrokinetic system was compared with conventional air-turbine-powered bur cutting. The hydrokinetic system cuts and bur preparations were randomly made on the buccal surfaces at the cervical one third of the crown and extended until exposure of the pulp was confirmed clinically. Pulpal temperatures associated with the hydrokinetic system either showed no change or decreased by up to 2 degrees C. Wet bur preparations resulted in a 3 degrees to 4 degrees C rise. With dry bur preparations, a 14 degrees C rise in temperature was recorded. Under the conditions of this study, the erbium,chromium:yttrium-scandium-gallium-garnet laser-powered hydrokinetic system, when used for cavity preparation, had no apparent adverse thermal effect as measured in the pulp space.

  16. Paramagnetic states in pristine and metallofullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Bartl, A. [Inst. fuer Festkoerperforschung im Inst. fuer Festkoerper- und Werkstofforschung e.V. Dresden (Germany); Dunsch, L. [Inst. fuer Festkoerperforschung im Inst. fuer Festkoerper- und Werkstofforschung e.V. Dresden (Germany); Kirbach, U. [Inst. fuer Festkoerperforschung im Inst. fuer Festkoerper- und Werkstofforschung e.V. Dresden (Germany); Schandert, B. [Inst. fuer Festkoerperforschung im Inst. fuer Festkoerper- und Werkstofforschung e.V. Dresden (Germany)

    1995-03-15

    Most pristine fullerenes give very weak ESR signals. The ESR spectra of soot extract and of the C-60, C-70 and higher fullerene fractions show signals of the same ESR linewidths of 0.1 mT but the spin concentrations differ markedly. The lowest spin concentration is found in the soot extract. After different temperature treatments the spin concentration increases. In pure C-60 and C-70 material the spin concentration is about 10{sup 17} spins/g, this is one unpaired electron per 1 000 to 10 000 fullerene molecules. Remarkable alternations of the concentrations of paramagnetic states and of the ESR linewidths can be observed with increasing treatment temperature above 300 C at pure fullerenes. It is concluded that the structure of the paramagnetic states does change. The reason is the removal of oxygen. Furthermore ESR spectroscopy is used to characterize the electronic states of endohedral systems. Fullerenes produced in presence of lanthanum, scandium, holmium and yttrium show resolved ESR spectra in solutions and lanthanum, scandium and holmium already in the solid soot extract which can be interpreted in terms of hyperfine coupling of an unpaired fullerene electron with the nuclear magnetic moments of the metal atoms. In some cases two species of the same metallofullerenes can be observed. Using these results different geometrical models of the investigated metallofullerenes can be predicted. (orig.)

  17. Structural transformations in Sc/Si multilayers irradiated by EUVlasers

    Energy Technology Data Exchange (ETDEWEB)

    Voronov, D.L.; Zubarev, E.N.; Pershyn, Y.P.; Sevryukova, V.A.; Kondratenko, V.V.; Vinogradov, A.V.; Artioukov, I.A.; Uspenskiy, Y.A.; Grisham, M.; Vaschenko, G.; Menoni, C.S.; Rocca, J.J.

    2007-08-21

    Multilayer mirrors for the extreme ultraviolet (EUV) are keyelements for numerous applications of coherent EUV sources such as newtabletop lasers and free-electron lasers. However the field ofapplications is limited by the radiation and thermal stability of themultilayers. Taking into account the growing power of EUV sources thestability of the optics becomes crucial. To overcome this problem it isnecessary to study the degradation of multilayers and try to increasetheir temporal and thermal stability. In this paper we report the resultsof detailed study of structural changes in Sc/Simultilayers when exposedto intense EUV laser pulses. Various types of surface damage such asmelting, boiling, shockwave creation and ablation were observed asirradiation fluencies increase. Cross-sectional TEM study revealed thatthe layer structure was completely destroyed in the upper part ofmultilayer, but still survived below. The layers adjacent tothe substrateremained intact even through the multilayer surface melted down, thoughthe structure of the layers beneath the molten zone was noticeablychanged. The layer structure in this thermally affected zone is similarto that of isothermally annealed samples. All stages of scandium silicideformation such as interdiffusion, solid-state amorphization, silicidecrystallization, etc., are present in the thermally affected zone. Itindicates a thermal nature of the damage mechanism. The tungstendiffusion barriers were applied to the scandium/silicon interfaces. Itwas shown that the barriers inhibited interdiffusion and increased thethermal stability of Sc/Si mirrors.

  18. Reducing the stochasticity of crystal nucleation to enable subnanosecond memory writing.

    Science.gov (United States)

    Rao, Feng; Ding, Keyuan; Zhou, Yuxing; Zheng, Yonghui; Xia, Mengjiao; Lv, Shilong; Song, Zhitang; Feng, Songlin; Ronneberger, Ider; Mazzarello, Riccardo; Zhang, Wei; Ma, Evan

    2017-12-15

    Operation speed is a key challenge in phase-change random-access memory (PCRAM) technology, especially for achieving subnanosecond high-speed cache memory. Commercialized PCRAM products are limited by the tens of nanoseconds writing speed, originating from the stochastic crystal nucleation during the crystallization of amorphous germanium antimony telluride (Ge2Sb2Te5). Here, we demonstrate an alloying strategy to speed up the crystallization kinetics. The scandium antimony telluride (Sc0.2Sb2Te3) compound that we designed allows a writing speed of only 700 picoseconds without preprogramming in a large conventional PCRAM device. This ultrafast crystallization stems from the reduced stochasticity of nucleation through geometrically matched and robust scandium telluride (ScTe) chemical bonds that stabilize crystal precursors in the amorphous state. Controlling nucleation through alloy design paves the way for the development of cache-type PCRAM technology to boost the working efficiency of computing systems. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  19. Comparative modeling of InP solar cell structures

    Science.gov (United States)

    Jain, R. K.; Weinberg, I.; Flood, D. J.

    1991-01-01

    The comparative modeling of p(+)n and n(+)p indium phosphide solar cell structures is studied using a numerical program PC-1D. The optimal design study has predicted that the p(+)n structure offers improved cell efficiencies as compared to n(+)p structure, due to higher open-circuit voltage. The various cell material and process parameters to achieve the maximum cell efficiencies are reported. The effect of some of the cell parameters on InP cell I-V characteristics was studied. The available radiation resistance data on n(+)p and p(+)p InP solar cells are also critically discussed.

  20. Systems analysis of Mars solar electric propulsion vehicles

    Science.gov (United States)

    Hickman, J. M.; Curtis, H. B.; Kenny, B. H.; Sefcik, R. J.

    1990-01-01

    Mission performance, mass, initial power, and cost are determined for solar electric propulsion vehicles across a range of payload masses, reference powers, and mission trajectories. Thick radiation shielding is added to arrays using indium phosphide or III-V multijunction solar cells to reduce the damage incurred through the radiation belts. Special assessments of power management and distribution systems, atmospheric drag, and energy storage are made. It is determined that atmospheric drag is of no great concern and that the energy storage used in countering drag is unnecessary. A scheme to package the arrays, masts, and ion thrusters into a single fairing is presented.

  1. Mid-infrared Laser System Development for Dielectric Laser Accelerators

    Science.gov (United States)

    Jovanovic, Igor; Xu, Guibao; Wandel, Scott

    Laser-driven particle accelerators based on dielectric laser acceleration are under development and exhibit unique and challenging pump requirements. Operation in the mid-infrared (5 μm) range with short pulses (500 μJ) and good beam quality is required. We present our progress on the design and development of a novel two- stage source of mid-infrared pulses for this application, which is based on optical parametric amplification. Beta barium borate and zinc germanium phosphide crystals are used, and are pumped by a Ti:sapphire ultrashort laser and seeded by self-phase modulation and parametric generation-based sources.

  2. Wastewater and Hazardous Waste Survey, Homestead AFB Florida.

    Science.gov (United States)

    1988-03-01

    acid, sodium salt Fulminic acid, mercury (11) salt (RIT) Heptachlor 1,2,3,4,10,10 0-Hexach lo ro-6,7 -epoxy-1, ,4,4a, 5,6,7,8,8a- octah ydro -e ndo...phosphide Isocyanic acid, methyl ester Mercury , (acetato-O) phenyl- Mercury fulminate (R,T) Methane, oxybis(chloro-) ~ ~ ~ Methane, tetranitro (R...analytical results from the wastewater survey showed mercury , silver, benzenes, chlorinated benzenes, fuel components, and various purgeable halocarbons above

  3. Palladium nanoparticles on InP for hydrogen detection

    Directory of Open Access Journals (Sweden)

    Zdansky Karel

    2011-01-01

    Full Text Available Abstract Layers of palladium (Pd nanoparticles on indium phosphide (InP were prepared by electrophoretic deposition from the colloid solution of Pd nanoparticles. Layers prepared by an opposite polarity of deposition showed different physical and morphological properties. Particles in solution are separated and, after deposition onto the InP surface, they form small aggregates. The size of the aggregates is dependent on the time of deposition. If the aggregates are small, the layer has no lateral conductance. Forward and reverse I-V characteristics showed a high rectification ratio with a high Schottky barrier height. The response of the structure on the presence of hydrogen was monitored.

  4. Single-photon emission from electrically driven InP quantum dots epitaxially grown on CMOS-compatible Si(001).

    Science.gov (United States)

    Wiesner, M; Schulz, W-M; Kessler, C; Reischle, M; Metzner, S; Bertram, F; Christen, J; Roßbach, R; Jetter, M; Michler, P

    2012-08-24

    The heteroepitaxy of III-V semiconductors on silicon is a promising approach for making silicon a photonic platform. Mismatches in material properties, however, present a major challenge, leading to high defect densities in the epitaxial layers and adversely affecting radiative recombination processes. However, nanostructures, such as quantum dots, have been found to grow defect-free even in a suboptimal environment. Here we present the first realization of indium phosphide quantum dots on exactly oriented Si(001), grown by metal-organic vapour-phase epitaxy. We report electrically driven single-photon emission in the red spectral region, meeting the wavelength range of silicon avalanche photodiodes' highest detection efficiency.

  5. Data readout system utilizing photonic integrated circuit

    Energy Technology Data Exchange (ETDEWEB)

    Stopiński, S., E-mail: S.Stopinski@tue.nl [COBRA Research Institute, Eindhoven University of Technology (Netherlands); Institute of Microelectronics and Optoelectronics, Warsaw University of Technology (Poland); Malinowski, M.; Piramidowicz, R. [Institute of Microelectronics and Optoelectronics, Warsaw University of Technology (Poland); Smit, M.K.; Leijtens, X.J.M. [COBRA Research Institute, Eindhoven University of Technology (Netherlands)

    2013-10-11

    We describe a novel optical solution for data readout systems. The core of the system is an Indium-Phosphide photonic integrated circuit performing as a front-end readout unit. It functions as an optical serializer in which the serialization of the input signal is provided by means of on-chip optical delay lines. The circuit employs electro-optic phase shifters to build amplitude modulators, power splitters for signal distribution, semiconductor optical amplifiers for signal amplification as well as on-chip reflectors. We present the concept of the system, the design and first characterization results of the devices that were fabricated in a multi-project wafer run.

  6. Toxicoses of the Ruminant Nervous System.

    Science.gov (United States)

    Niles, Gene A

    2017-03-01

    This article discusses the etiology, mechanism of action, clinical signs, and diagnostic tests used to identify toxic agents that affect the nervous system of ruminants. The article is not intended to be an exhaustive review of each agent, but a reference for establishing a differential diagnosis when toxic agents are suspected as the cause of central nervous system disease in ruminants. The initial focus of the article is on agents that cause brain lesions consistent with polioencephalomalacia. Other neurotoxic disease agents include bovine bonkers, urea, organophosphate, organochlorine, cyanobacteria, zinc, aluminum, phosphide, metaldehyde, strychnine, botulism, tetanus, clostridium perfringens, and poisonous plants. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. 180-GHz I-Q Second Harmonic Resistive Mixer MMIC

    Science.gov (United States)

    Kangaslahti, Pekka P.; Lai, Richard; Mei, Xiaobing

    2010-01-01

    An indium phosphide MMIC (monolithic microwave integrated circuit) mixer was developed, processed, and tested in the NGC 35-nm-gate-length HEMT (high electron mobility transistor) process. This innovation is very compact in size and operates with very low LO power. Because it is a resistive mixer, this innovation does not require DC power. This is an enabling technology for the miniature receiver modules for the GeoSTAR instrument, which is the only viable option for the NRC decadal study mission PATH.

  8. 99 W mid-IR operation of a ZGP OPO at 25% duty cycle.

    Science.gov (United States)

    Hemming, Alexander; Richards, Jim; Davidson, Alan; Carmody, Neil; Bennetts, Shayne; Simakov, Nikita; Haub, John

    2013-04-22

    We have demonstrated the highest reported output power from a mid-IR ZGP OPO. The laser is a cascaded hybrid system consisting of a thulium fibre laser, Ho:YAG solid state laser and a Zinc Germanium Phosphide parametric oscillator. The system produces 27 W of output power in the 3-5 μm wavelength range with an M(2) = 4.0 when operating in a repetitively q-switched mode, and a modulated peak output power of 99 W at a reduced duty cycle of 25%.

  9. A Narrow Linewidth Singly Resonant ZGP OPO for Multiple Lidar Applications

    Science.gov (United States)

    Yu, Jirong; Lee, Hyung R.; Bai, Yingxin; Barnes, Norman P.

    2006-01-01

    A singly resonant, injection seeded Zinc Germanium Phosphide (ZGP) optical parametric oscillator (OPO), capable to tune over 4.3-10.1 microns, is demonstrated. This ZGP OPO uses a bow-tie cavity with a partially reflective mirror for injection seeding at the signal wavelength. The injection seed source can be either a continuous wave 3.39 m laser or a tunable near-infrared OPO laser, which provides wide wavelength tuning capability. The injection seeded ZGP OPO narrows the idler wavelength linewidth to less than 1nm, limited by the measurement resolution of the monochromator. This device has potential to be used as a transmitter for multiple purpose lidar applications.

  10. Electroluminescence

    CERN Document Server

    Henisch, H K

    1962-01-01

    Electroluminescence deals with the multiplicity of forms related to electroluminescence phenomena. The book reviews some basic observations of electroluminescence, the Gudden-Pohl and Dechene effects, the electroluminescence phenomena in zinc sulfide phosphors, in silicon carbide, and in compounds composed of elements in groups III and V of the Periodic Table (such as gallium phosphide). The text also explains polarization of free charge carriers, the outline of junction breakdown theory, carrier recombination, and phosphor suspensions. The book describes the growth of zinc sulfide crystals (f

  11. Development of Non-Toxic Quantum Dots for Flexible Display Applications

    Science.gov (United States)

    2013-11-14

    and VI (Fig. 2) have significant impact on our day to day life. Materials such as CdSe, ZnS, CdS, CdTe , GaAs, aluminum gallium arsenide (AlGaAs...gallium nitride (GaN), indium phosphide (InP), zincselenide (ZnSe), cadmiumtelluride ( CdTe ), and copper indium gallium selenide Cu(In1-xGax)Se2 (CIGS...regards specifically to InGaN, full compositional tunability has been claimed in nanowires, though mild compositional modulation was observed for 70

  12. Synthesis, structure and reactivity of rare-earth metal complexes containing anionic phosphorus ligands.

    Science.gov (United States)

    Li, Tianshu; Kaercher, Sabrina; Roesky, Peter W

    2014-01-07

    A comprehensive review of structurally characterized rare-earth metal complexes containing anionic phosphorus ligands is presented. Since rare-earth elements form hard ions and phosphorus is considered as a soft ligand, the rare-earth metal phosphorus coordination is regarded as a less favorite combination. Three classes of phosphorus ligands, (1) the monoanionic organophosphide ligands (PR2(-)) bearing one negative charge on the phosphorus atom; (2) the dianionic phosphinidene (PR(2-)) and P(3-) ligands; and (3) the pure inorganic polyphosphide ligands (Pn(x-)), are included here. Particular attention has been paid to the synthesis, structure, and reactivity of the rare-earth metal phosphides.

  13. Systems analysis of Mars solar electric propulsion vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Hickman, J.M.; Curtis, H.B.; Kenny, B.H.; Sefcik, R.J.

    1990-01-01

    Mission performance, mass, initial power, and cost are determined for solar electric propulsion vehicles across a range of payload masses, reference powers, and mission trajectories. Thick radiation shielding is added to arrays using indium phosphide or III-V multijunction solar cells to reduce the damage incurred through the radiation belts. Special assessments of power management and distribution systems, atmospheric drag, and energy storage are made. It is determined that atmospheric drag is of no great concern and that the energy storage used in countering drag is unnecessary. A scheme to package the arrays, masts, and ion thrusters into a single fairing is presented. 19 refs.

  14. High-pressure and high-temperature powder diffraction on molybdenum diphosphide, MoP{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Soto, V. [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Esenada (Mexico); Knorr, K.; Ehm, L. [Christian-Albrechts-Univ. zu Kiel, Inst. fuer Geowissenschaften, Mineralogie/Kristallographie, Kiel (Germany); Baehtz, C. [HASYLAB Hamburg and TU Darmstadt, Materialwissenschaften, Darmstadt (Germany); Winkler, B. [Johann-Wolfgang-Goethe Univ. Frankfurt-Main, Mineralogie, Frankfurt/M. (Germany); Avalos-Borja, M. [Centro de Ciencias de la Materia Condensada, Univ. Nacional Autonoma de Mexico, Ensenada, BC (Mexico)

    2004-07-01

    The isothermal compressibility and bulk thermal expansion of molybdenum diphosphide, MoP{sub 2}, were measured by in-situ X-ray powder diffraction from ambient conditions to 6.8 GPa and 839 K, respectively. A small anisotropy of the compressibilities in MoP{sub 2} appears to be governed by non-bonding interactions in this layer-like material. The thermal expansion data are compared to molybdenum phosphide, MoP, which was measured to 1262 K. (orig.)

  15. Numerical Self-Consistent Analysis of VCSELs

    Directory of Open Access Journals (Sweden)

    Robert Sarzała

    2012-01-01

    Full Text Available Vertical-cavity surface-emitting lasers (VCSELs yield single-longitudinal-mode operation, low-divergence circular output beam, and low threshold current. This paper gives an overview on theoretical, self-consistent modelling of physical phenomena occurring in a VCSEL. The model has been experimentally confirmed. We present versatile numerical methods for nitride, arsenide, and phosphide VCSELs emitting light at wavelengths varying from violet to near infrared. We also discuss different designs with respect to optical confinement: gain guidance using tunnel junctions and index guidance using oxide confinement or photonic crystal and we focus on the problem of single-transverse-mode operation.

  16. Enhanced EOS photovoltaic power system capability with InP solar cells

    Science.gov (United States)

    Bailey, Sheila G.; Weinberg, Irving; Flood, Dennis J.

    1991-01-01

    The Earth Observing System (EOS), which is part of the International Mission to Planet Earth, is NASA's main contribution to the Global Change Research Program which opens a new era in international cooperation to study the Earth's environment. Five large platforms are to be launched into polar orbit, two by NASA, two by ESA, and one by the Japanese. In such an orbit the radiation resistance of indium phosphide solar cells combined with the potential of utilizing five micron cell structures yields an increase of 10 percent in the payload capability. If further combined with the advanced photovoltaic solar array the payload savings approaches 12 percent.

  17. Synthesis of InP nanoneedles and their use as Schottky devices

    OpenAIRE

    Strupeit, Tim; Klinke, Christian; Kornowski, Andreas; Weller, Horst

    2010-01-01

    Indium phosphide (InP) nanostructures have been synthesized by means of colloidal chemistry. Under appropriate conditions needle-shaped nanostructures composed of an In head and an InP tail with lengths up to several micrometers could be generated in a one-pot synthesis. The growth is interpreted in terms of simultaneous decomposition of the In precursor and in situ generation of In and InP nanostructures. Owing to their specific design such In/InP nanoneedles suit the use as ready-made Schot...

  18. Silicon-nanocrystal Optoelectronic Kerr Effect for Complementary Metal-oxide Semiconductor (CMOS) Compatible Optical Switching

    Science.gov (United States)

    2011-04-01

    phosphide (InGaAsP) or electro-optic materials such as lithium niobate (LiNbO3). These materials have a long history of optimization, but their integration...10–12 cm2/W has been found in Si-nc (1). The Si-nc layer would be fabricated using equipment at the Rochester Institute of Technology (RIT) and the...sandwiched between the Si layers (red). An oxide layer (light gray) separates the active device layers from the Si substrate (green). Light enters

  19. Efficient telecom to visible wavelength conversion in doubly resonant GaP microdisks

    CERN Document Server

    Lake, David P; Jayakumar, Harishankar; Santos, Laís Fujii dos; Curic, Davor; Barclay, Paul E

    2015-01-01

    Resonant second harmonic generation between 1550 nm and 775 nm with outside efficiency $> 4.4\\times10^{-4}\\, \\text{mW}^{-1}$ is demonstrated in a gallium phosphide microdisk cavity supporting high-$Q$ modes at visible ($Q \\sim 10^4$) and infrared ($Q \\sim 10^5$) wavelengths. The double resonance condition was satisfied through intracavity photothermal temperature tuning using $\\sim 360\\,\\mu$W of 1550 nm light input to a fiber taper and resonantly coupled to the microdisk. Above this pump power efficiency was observed to decrease. The observed behavior is consistent with a simple model for thermal tuning of the double resonance condition.

  20. Magneto-optic effects in doped InP

    Science.gov (United States)

    Syed, Maarij; Siahmakoun, Azad

    2005-09-01

    We report on the investigation of Faraday rotation (FR) of indium phosphide (InP) conducted for several different wavelengths at room temperature. Appreciable FR, yielding Verdet constant values at 980, 1064, 1320, and 1550 nm at room temperature, has been observed. We have also investigated the role for dopants in FR for this class of materials. Specifically we have investigated an n-type dopant (Sulfur) and p-type dopants (Cd and Fe). We also present a simple and consistent model that explains the results for sulfur and points to the need for a more systematic study of these materials.

  1. Pulsed laser deposition-assisted synthesis of porous WP2 nanosheet arrays integrated on graphite paper as a 3D flexible cathode for efficient hydrogen evolution

    Science.gov (United States)

    Pi, Mingyu; Guo, Weimeng; Wu, Tianli; Wang, Xiaodeng; Zhang, Dingke; Wang, Shuxia; Chen, Shijian

    2017-10-01

    Herein, porous WP2 nanosheet arrays integrated on graphite paper (P-WP2 NSs/GP) as 3D flexible cathode for electrocatalytic hydrogen evolution reaction (HER) are prepared by in situ phosphidation via vacuum encapsulation assisted by pulsed laser deposition technique. Compared to the electrode without pre-deposition process, the enhanced catalytic activities are attributed to the increased effective catalyst loading and the reinforced charge transport kinetics. The results make the present P-WP2 NSs/GP as a promising cathode for energy conversion and paves a new way for designing and fabricating efficient electrodes toward HER.

  2. Investigation of 2D photonic crystal structure based channel drop filter using quad shaped photonic crystal ring resonator for CWDM system

    Energy Technology Data Exchange (ETDEWEB)

    Chhipa, Mayur Kumar, E-mail: mayurchhipa1@gmail.com; Dusad, Lalit Kumar [Government Engineering College Ajmer, Rajasthan (India); Rajasthan Technical University, Kota, Rajasthan (India)

    2016-05-06

    In this paper, the design & performance of two dimensional (2-D) photonic crystal structure based channel drop filter is investigated using quad shaped photonic crystal ring resonator. In this paper, Photonic Crystal (PhC) based on square lattice periodic arrays of Gallium Indium Phosphide (GaInP) rods in air structure have been investigated using Finite Difference Time Domain (FDTD) method and photonic band gap is being calculated using Plane Wave Expansion (PWE) method. The PhC designs have been optimized for telecommunication wavelength λ= 1571 nm by varying the rods lattice constant. The number of rods in Z and X directions is 21 and 20, with lattice constant 0.540 nm it illustrates that the arrangement of Gallium Indium Phosphide (GaInP) rods in the structure which gives the overall size of the device around 11.4 µm × 10.8 µm. The designed filter gives good dropping efficiency using 3.298, refractive index. The designed structure is useful for CWDM systems. This device may serve as a key component in photonic integrated circuits. The device is ultra compact with the overall size around 123 µm{sup 2}.

  3. Molybdenum phosphosulfide: an active, acid-stable, earth-abundant catalyst for the hydrogen evolution reaction.

    Science.gov (United States)

    Kibsgaard, Jakob; Jaramillo, Thomas F

    2014-12-22

    Introducing sulfur into the surface of molybdenum phosphide (MoP) produces a molybdenum phosphosulfide (MoP|S) catalyst with superb activity and stability for the hydrogen evolution reaction (HER) in acidic environments. The MoP|S catalyst reported herein exhibits one of the highest HER activities of any non-noble-metal electrocatalyst investigated in strong acid, while remaining perfectly stable in accelerated durability testing. Whereas mixed-metal alloy catalysts are well-known, MoP|S represents a more uncommon mixed-anion catalyst where synergistic effects between sulfur and phosphorus produce a high-surface-area electrode that is more active than those based on either the pure sulfide or the pure phosphide. The extraordinarily high activity and stability of this catalyst open up avenues to replace platinum in technologies relevant to renewable energies, such as proton exchange membrane (PEM) electrolyzers and solar photoelectrochemical (PEC) water-splitting cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Thermoelectric characteristics of iron silicide thermoelectric converter with the transition metallic compound as an additive; Sen`i kinzoku kagobutsu wo tenkabutsu to shita keikatetsu netsuden soshi no netsuden tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Hayashibara, M.; Oda, M. [Hitachi, Ltd., Tokyo (Japan)

    1994-04-13

    The thin film must be converted into a bulky shape in order that the high electric power may be produced by the iron silicide thermoelectric converter. Study was then made to establish the homogeneous bulk production method, in which the additive must diffuse sufficiently in the iron silicide and bond strongly to it during the sintering. Selected as an additive in the present study, Co compounds were all decomposed below the sintering temperature and remained in the iron silicide. The Co sulfide, phosphide, bromide and iodide were particularly high in reactivity with the iron silicide. The Co, of which the added quantity was proportional to the electric conductivity, was almost homogenized into a solid solution. In the experiment, both Co sulfide and phosphide were equal in thermoelectric power as an additive. The Co bromide and iodide were maximally about 10% and 50%, respectively lower in thermoelectric power than the Co sulfide. It is attributable to the FeSi2 reformed to the electrically insulating SiO2 and low-thermoelectric power FeSi, because both Co bromide and iodide are oxidizing compounds. 7 refs., 10 figs.

  5. Poultry egg components as cereal bait additives for enhancing rodenticide based control success and trap index of house rat, Rattus rattus.

    Science.gov (United States)

    Singla, Neena; Kanwar, Deepia

    2014-05-01

    To compare the acceptance and efficacy of cereal bait containing different concentrations of poultry egg components in laboratory and poultry farms to control house rat, Rattus rattus (R. rattus). Acceptance of cereal bait containing different concentrations (2%, 5% and 10%) of poultry egg components such as egg shell powder (ESP), egg albumin (EA) and crushed egg shell as bait additives were studied after exposing them to different groups of rats in bi-choice with bait without additive. Behaviour of rats towards cereal bait containing 2% concentration of different egg components was recorded in no-choice conditions through Food Scale Consumption Monitor. In poultry farm predominantly infested with R. rattus, acceptance and efficacy of 2% zinc phosphide bait containing 2% EA and ESP was evaluated. Trap success of single rat traps containing chapatti pieces smeared with 2% EA and 2% ESP was also evaluated in poultry farm. In bi-choice tests, significantly (Pegg albumin and egg shell powder in cereal bait to enhance acceptance and efficacy of 2% zinc phosphide bait against R. rattus. This may further help in checking the spread of rodent borne diseases to animals and humans.

  6. A three-dimensional porous MoP@C hybrid as a high-capacity, long-cycle life anode material for lithium-ion batteries.

    Science.gov (United States)

    Wang, Xia; Sun, Pingping; Qin, Jinwen; Wang, Jianqiang; Xiao, Ying; Cao, Minhua

    2016-05-21

    Metal phosphides are great promising anode materials for lithium-ion batteries with a high gravimetric capacity. However, significant challenges such as low capacity, fast capacity fading and poor cycle stability must be addressed for their practical applications. Herein, we demonstrate a versatile strategy for the synthesis of a novel three-dimensional porous molybdenum phosphide@carbon hybrid (3D porous MoP@C hybrid) by a template sol-gel method followed by an annealing treatment. The resultant hybrid exhibits a 3D interconnected ordered porous structure with a relatively high surface area. Benefiting from its advantages of microstructure and composition, the 3D porous MoP@C hybrid displays excellent lithium storage performance as an anode material for lithium-ion batteries in terms of specific capacity, cycling stability and long-cycle life. It presents stable cycling performance with a high reversible capacity up to 1028 mA h g(-1) at a current density of 100 mA g(-1) after 100 cycles. By ex situ XRD, HRTEM, SAED and XPS analyses, the 3D porous MoP@C hybrid was found to follow the Li-intercalation reaction mechanism (MoP + xLi(+) + e(-)↔ LixMoP), which was further confirmed by ab initio calculations based on density functional theory.

  7. Evaluation of critical materials in five additional advance design photovoltaic cells

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S.A.; Watts, R.L.; Martin, P.; Gurwell, W.E.

    1981-02-01

    The objective of this study is to identify potential material supply constraints due to the large-scale deployment of five advanced photovoltaic (PV) cell designs, and to suggest strategies to reduce the impacts of these production capacity limitations and potential future material shortages. The Critical Materials Assessment Program (CMAP) screens the designs and their supply chains and identifies potential shortages which might preclude large-scale use of the technologies. The results of the screening of five advanced PV cell designs are presented: (1) indium phosphide/cadmium sulfide, (2) zinc phosphide, (3) cadmium telluride/cadmium sulfide, (4) copper indium selenium, and (5) cadmium selenide photoelectrochemical. Each of these five cells is screened individually assuming that they first come online in 1991, and that 25 Gwe of peak capacity is online by the year 2000. A second computer screening assumes that each cell first comes online in 1991 and that each cell has a 5 GWe of peak capacity by the year 2000, so that the total online capacity for the five cells is 25 GWe. Based on a review of the preliminary baseline screening results, suggestions were made for varying such parameters as the layer thickness, cell production processes, etc. The resulting PV cell characterizations were then screened again by the CMAP computer code. The CMAP methodology used to identify critical materials is described; and detailed characterizations of the advanced photovoltaic cell designs under investigation, descriptions of additional cell production processes, and the results are presented. (WHK)

  8. Porous Structured Ni-Fe-P Nanocubes Derived from a Prussian Blue Analogue as an Electrocatalyst for Efficient Overall Water Splitting.

    Science.gov (United States)

    Xuan, Cuijuan; Wang, Jie; Xia, Weiwei; Peng, Zongkai; Wu, Zexing; Lei, Wen; Xia, Kedong; Xin, Huolin L; Wang, Deli

    2017-08-09

    Exploring nonprecious metal electrocatalysts to replace the noble metal-based catalysts for full water electrocatalysis is still an ongoing challenge. In this work, porous structured ternary nickel-iron-phosphide (Ni-Fe-P) nanocubes were synthesized through one-step phosphidation of a Ni-Fe-based Prussian blue analogue. The Ni-Fe-P nanocubes exhibit a rough and loose porous structure on their surface under suitable phosphating temperature, which is favorable for the mass transfer and oxygen diffusion during the electrocatalysis process. As a result, Ni-Fe-P obtained at 350 °C with poorer crystallinity offers more unsaturated atoms as active sites to expedite the absorption of reactants. Additionally, the introduction of nickel improved the electronic structure and then reduced the charge-transfer resistance, which would result in a faster electron transport and an enhancement of the intrinsic electrocatalytic activities. Benefiting from the unique porous nanocubes and the chemical composition, the Ni-Fe-P nanocubes exhibit excellent hydrogen evolution reaction and oxygen evolution reaction activities in alkaline medium, with low overpotentials of 182 and 271 mV for delivering a current density of 10 mA cm-2, respectively. Moreover, the Ni-Fe-P nanocubes show outstanding stability for sustained water splitting in the two-electrode alkaline electrolyzer. This work not only provides a facile approach for designing bifunctional electrocatalysts but also further extends the application of metal-organic frameworks in overall water splitting.

  9. Conceptual design of a lunar base solar power plant lunar base systems study task 3.3

    Science.gov (United States)

    1988-01-01

    The best available concepts for a 100 kW Solar Lunar Power Plant based on static and dynamic conversion concepts have been examined. The two concepts which emerged for direct comparison yielded a difference in delivered mass of 35 MT, the mass equivalent of 1.4 lander payloads, in favor of the static concept. The technologies considered for the various elements are either state-of-the-art or near-term. Two photovoltaic cell concepts should receive high priority for development: i.e., amorphous silicon and indium phosphide cells. The amorphous silicon, because it can be made so light weight and rugged; and the indium phosphide, because it shows very high efficiency potential and is reportedly not degraded by radiation. Also the amorphous silicon cells may be mounted on flexible backing that may roll up much like a carpet for compact storage, delivery, and ease of deployment at the base. The fuel cell and electrolysis cell technology is quite well along for lunar base applications, and because both the Shuttle and the forthcoming Space Station incorporate these devices, the status quo will be maintained. Early development of emerging improvements should be implemented so that essential life verification test programs may commence.

  10. A Novel Bis(phosphido)pyridine [PNP] 2− Pincer Ligand and Its Potassium and Bis(dimethylamido)zirconium(IV) Complexes

    KAUST Repository

    Winston, Matthew S.

    2010-12-13

    A novel PNP bis(secondary phosphine)pyridine pincer ligand, 2,6-bis(2-(phenylphosphino)phenyl)pyridine, has been prepared in high yield, and the properties of the doubly deprotonated form as a ligand in K 4(PNP)2(THF)6 and (PNP)Zr(NMe2) 2 have been investigated. The neutral PNP ligand has been isolated as a mixture of noninterconverting diastereomers, due to the presence of two chirogenic phosphorus atoms of the secondary phopshines, but coordination of the dianionic form to potassium and zirconium allows for isolation of a single diastereomer in near-quantitative yield. The structure of a bis(dimethylamido) zirconium(IV) derivative of the bis(phosphido)pyridine ligand and DFT calculations suggest that the phosphides do not π-bond to early transition metals, likely due to geometric strain and possibly orbital size mismatch between phosphorus and zirconium. As a result, the soft phosphides are prone to formation of insoluble oligomers with substantial bridging of the phosphido lone pairs to other zirconium centers. © 2010 American Chemical Society.

  11. Rational Design of Three-Dimensional Graphene Encapsulated with Hollow FeP@Carbon Nanocomposite as Outstanding Anode Material for Lithium Ion and Sodium Ion Batteries.

    Science.gov (United States)

    Wang, Xiujuan; Chen, Kai; Wang, Gang; Liu, Xiaojie; Wang, Hui

    2017-10-24

    Transition metal phosphides have been extensively investigated owing to their high theoretical capacities and relatively low intercalation potentials vs Li/Li(+), but their practical applications have been hindered by low electrical conductivity and dramatic volume variation during cycling. In this work, an interesting strategy for the rational design of graphene (GR) encapsulated with a hollow FeP@carbon nanocomposite (H-FeP@C@GR) via a combination of a hydrothermal route, a carbon-coating process, phosphidation treatment, and carbothermic reaction is reported. The hollow FeP (H-FeP) nanospheres shelled with thin carbon layers are wonderfully incorporated into the GR matrix, interconnecting to form a three-dimensional (3D) hierarchical architecture. Such a design offers distinct advantages for FeP-based anode materials for both lithium ion batteries (LIBs) and sodium ion batteries (SIBs). For example, the 3D omnibearing conductive networks from the GR skeleton and outer coating carbon can provide an open freeway for electron/ion transport, promoting the electrode reaction kinetics. In addition, the wrapping of an H-FeP nanosphere in a thin carbon layer enables the formation of a solid electrolyte interphase (SEI) on the carbon layer surface instead of on the individual H-FeP surface, preventing the continual re-forming of the SEI. When used as anode materials for LIBs and SIBs, H-FeP@C@GR exhibited excellent electrochemistry performances.

  12. Experimental Study of Codeposition Electrochemistry Using Mixtures of ScCl3 and YCl3 in LiCl-KCl Eutectic Salt at 500°C

    Energy Technology Data Exchange (ETDEWEB)

    Shaltry, Michael R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Yoo, Tae-Sic [Idaho National Lab. (INL), Idaho Falls, ID (United States); Fredrickson, Guy L. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-09-12

    Cyclic voltammetry and chronopotentiometry tests were applied to molten LiCl-KCl eutectic at 500 °C including amounts of ScCl3 and YCl3. The purpose of the testing was to observe the effect of applied electrical current on the codeposition of scandium and yttrium, which were chosen as surrogate elements for uranium and plutonium, respectively. Features of the work were to vary the concentration of ScCl3 (at relatively low concentrations) as well as varying the applied current, all with a fixed concentration of YCl3. Results of the experiments could provide insight of uranium electrorefining and may provide evidence, which suggests the electrorefiner could be operated at lower UCl3 concentration whereby codeposition (U and Pu) could be more effectively controlled.

  13. Low work function materials for microminiature energy conversion and recovery applications

    Energy Technology Data Exchange (ETDEWEB)

    Zavadil, Kevin R.; Ruffner, Judith A.; King, Donald B.

    2003-05-13

    Low work function materials are disclosed together with methods for their manufacture and integration with electrodes used in thermionic conversion applications (specifically microminiature thermionic conversion applications). The materials include a mixed oxide system and metal in a compositionally modulated structure comprised of localized discontinuous structures of material that are deposited using techniques suited to IC manufacture, such as rf sputtering or CVD. The structures, which can include layers are then heated to coalescence yielding a thin film that is both durable and capable of electron emission under thermionic conversion conditions used for microminiature thermionic converters. Using the principles of the invention, thin film electrodes (emitters and collectors) required for microconverter technology are manufactured using a single process deposition so as to allow for full fabrication integration consistent with batch processing, and tailoring of emission/collection properties. In the preferred embodiment, the individual layers include mixed BaSrCaO, scandium oxide and tungsten.

  14. Novel acridone-modified MCM-41 type silica: Synthesis, characterization and fluorescence tuning

    Directory of Open Access Journals (Sweden)

    Maximilian Hemgesberg

    2011-06-01

    Full Text Available A Mobil Composition of Matter (MCM-41 type mesoporous silica material containing N-propylacridone groups has been successfully prepared by co-condensation of an appropriate organic precursor with tetraethyl orthosilicate (TEOS under alkaline sol–gel conditions. The resulting material was fully characterized by means of X-ray diffraction (XRD, N2-adsorption–desorption, transmission electron microscopy (TEM, IR and UV–vis spectroscopy, as well as 29Si and 13C CP-MAS NMR techniques. The material features a high inner surface area and a highly ordered two-dimensional hexagonal pore structure. The fluorescence properties of the organic chromophore can be tuned via complexation of its carbonyl group with scandium triflate, which makes the material a good candidate for solid state sensors and optics. The successful synthesis of highly ordered MCM materials through co-condensation was found to be dependent on the chemical interaction of the different precursors.

  15. The Influence of Titania Electrode Modification with Lanthanide Ions Containing Thin Layer on the Performance of Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Maciej Zalas

    2012-01-01

    Full Text Available The lanthanide and scandium groups ions (except Pm and Ac have been used as dopants of TiO2 film in dye-sensitized solar cells. The X-ray diffraction spectra show that the modification has no influence on the structure of the electrode; however, the diffuse reflectance UV-Vis measurements exhibit significant changes in the electronic properties of modified electrodes. The appearance of energy barrier preventing photoexcited electron back-transfer was confirmed for Sc, Ce, Sm, Tb, Ho, Tm, and Lu modified cells. The best photoconversion performance of 8.88 and 8.80% was found for samples modified with Ce and Yb, respectively, and it was greater by 31.4 and 30.2% than that of a unmodified cell.

  16. Magnetic anisotropy in the incommensurate ScFe{sub 4}Al{sub 8} system

    Energy Technology Data Exchange (ETDEWEB)

    Rećko, K., E-mail: k.recko@uwb.edu.pl [Faculty of Physics, University of Białystok, K. Ciołkowskiego 1L, 15-245 Białystok (Poland); Dobrzyński, L. [National Centre for Nuclear Research, A. Soltan 7, 05-400 Otwock-Świerk (Poland); Waliszewski, J.; Szymański, K. [Faculty of Physics, University of Białystok, K. Ciołkowskiego 1L, 15-245 Białystok (Poland)

    2015-08-15

    Neutron scattering and magnetization data are used for estimation of the spin ordering in ScFe{sub 4}Al{sub 8}. Results of experimental measurements are compared with the ground state configurations obtained by simulated annealing algorithms. The origins of the magnetocrystalline anisotropy of the scandium intermetallic alloy and the conditions of the coexistence of two different magnetic modulations as a function of the exchange integrals are discussed. The influence of the dipolar interactions for the noncollinearity and incommensurability in ScFe{sub 4}Al{sub 8} was determined. - Highlights: • We found dipolar and DM interactions as the anisotropy origins of 3d–3d–3p alloy. • We covered the explanation of incommensurability and noncollinearity of ScFe{sub 4}Al{sub 8}. • We discussed the magnetism resulting from competitiveness of exchange effects.

  17. Enhanced hardness in epitaxial TiAlScN alloy thin films and rocksalt TiN/(Al,Sc)N superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Bivas [School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); Lawrence, Samantha K.; Bahr, David F. [School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Schroeder, Jeremy L.; Birch, Jens [Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, SE-581 83 Linköping (Sweden); Sands, Timothy D. [School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

    2014-10-13

    High hardness TiAlN alloys for wear-resistant coatings exhibit limited lifetimes at elevated temperatures due to a cubic-AlN to hexagonal-AlN phase transformation that leads to decreasing hardness. We enhance the hardness (up to 46 GPa) and maximum operating temperature (up to 1050 °C) of TiAlN-based coatings by alloying with scandium nitride to form both an epitaxial TiAlScN alloy film and epitaxial rocksalt TiN/(Al,Sc)N superlattices on MgO substrates. The superlattice hardness increases with decreasing period thickness, which is understood by the Orowan bowing mechanism of the confined layer slip model. These results make them worthy of additional research for industrial coating applications.

  18. In situ TEM investigation of microstructural behavior of superplastic Al–Mg–Sc alloy

    Energy Technology Data Exchange (ETDEWEB)

    Dám, Karel, E-mail: damk@vscht.cz [Department of Metals and Corrosion Engineering, Institute of Chemical Technology, Prague, Technická 5, 166 28 Prague 6 (Czech Republic); Institute of Physics of the ASCR, Na Slovance 2, 182 21 Prague 8 (Czech Republic); Lejček, Pavel, E-mail: lejcekp@fzu.cz [Institute of Physics of the ASCR, Na Slovance 2, 182 21 Prague 8 (Czech Republic); Michalcová, Alena [Department of Metals and Corrosion Engineering, Institute of Chemical Technology, Prague, Technická 5, 166 28 Prague 6 (Czech Republic)

    2013-02-15

    Dynamic changes in microstructure of the superplastic ultrafine-grained Al–3Mg–0.2Sc (wt.%) alloy refined by equal-channel angular pressing (ECAP). were observed by in situ transmission electron microscopy at temperatures up to 300 °C (annealing and tensile deformation) in order to simulate the initial stages of superplastic testing. It was found that the microstructure changes significantly during the preheating before the superplastic deformation, which was accompanied by decreased microhardness. During the deformation at 300 °C, high dislocation activity as well as motion of low-angle grain boundaries was observed while high-angle grain boundaries did not move due to the presence of scandium in the alloy. - Highlights: ► We performed in situ TEM annealing and straining on superplastic Al–Mg–Sc alloy. ► We simulated the conditions of early stages of superplastic testing. ► Significant changes in microstructure occur during preheating before deformation.

  19. High strength aluminum cast alloy: A Sc modification of a standard Al–Si–Mg cast alloy

    Energy Technology Data Exchange (ETDEWEB)

    Muhammad, Arfan, E-mail: engr.arfan@gmail.com [Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education, School of Material Science and Engineering, Beihang University, Beijing 100191 (China); Xu, Cong; Xuejiao, Wang [Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education, School of Material Science and Engineering, Beihang University, Beijing 100191 (China); Hanada, Shuji [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Yamagata, Hiroshi [Center for Advanced Die Engineering and Technology, Gifu University, 1-1 Yanagido, Gifu City, Gifu 501-1193 (Japan); Hao, LiRong [Hebei Sitong New Metal Material Co., Ltd., Baoding 071105 (China); Chaoli, Ma [Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education, School of Material Science and Engineering, Beihang University, Beijing 100191 (China)

    2014-05-01

    A standard Aluminum–Silicon–Magnesium cast alloy (A357 foundry alloy without Beryllium) modified with different weight percentages of Scandium (Sc), has been studied to evaluate the effects of Sc contents on microstructure and strength. Study has been conducted under optimized parameters of melting, casting and heat treatment. Characterization techniques like optical microscopy, SEM, TEM and tensile testing were employed to analyze the microstructure and mechanical properties. Results obtained in this research indicate that with the increase of Sc contents up to 0.4 wt%, grain size is decreased by 80% while ultimate tensile strength and hardness are increased by 28% and 19% respectively. Moreover along with the increase in strength, elongation to failure is also increased up to 165%. This is quite interesting behavior because usually strength and ductility have inverse relationship.

  20. Modification of aluminium alloys with rare metals – the basis for advanced materials in construction and transport

    Directory of Open Access Journals (Sweden)

    Skachkov Vladimir Mikchaylovich

    2016-06-01

    Full Text Available The method of process powder injection into aluminum melt shows much promise. Scandium is injected by the high-temperature exchange reaction between the salt melt and aluminum. The best salt compositions were selected. The results of the process are considered to depend on the initial salts. A series of fusions was performed under production conditions at the Kamensk-Uralskii metallurgical plant. It was shown that the injection method for production of aluminoscandium master alloys is technologically feasible. To protect intellectual property of authors, employees of the Institute of Solid State Chemistry, Ural branch of RAS (Russia a patent «Method of alloying of aluminium or alloys on its basis» RU № 2534182 of 27.11.2014 was registered.

  1. Characterization of potassic materials of Pocos de Caldas alkaline massif, Southeastern Brazil; Caracterizacao de materiais potassicos do macico alcalino de Pocos de Caldas (MG)

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, P.; Navarro, F.C.; Roveri, C.D. [Universidade Federal de Alfenas (UNIFAL), MG (Brazil); Bergerman, M.G., E-mail: pattypgpatty@gmail.com [Universidade de Sao Paulo (USP), SP (Brazil)

    2016-07-01

    Potassium, which has featured in Brazil's agricultural sector and in the world's in the application of fertilizers, is present in magmatic rocks, such as nepheline syenite and phonolite, found in the Alkaline Massif of Pocos de Caldas (AMPC). The rare earth elements (REE), in turn, also occur in this region and have important uses in various industrial fields. The aim of this study was to investigate the potential of potassic rocks of AMPC in the fertilizer and rare earths industry. Five samples were collected and characterized. It was observed that there was no preferential concentration by granulometric range of potassium oxide, alumina, silica and iron oxide. Feldspathic mass, potash feldspar, and muscovite were found in all samples. The samples show REE with amounts greater than those found in the earth's crust, except for lutetium and scandium and possessed average content of potassium oxide from 8.70 to 14.40%. (author)

  2. Bandgap in Al{sub 1-x}Sc{sub x}N

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Ruopeng; Evans, Sarah R.; Gall, Daniel [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2013-03-18

    Aluminum scandium nitride (Al{sub 1-x}Sc{sub x}N) layers deposited by reactive magnetron co-sputtering on sapphire 0001 substrates at 850 Degree-Sign C are epitaxial single-crystals for x {<=} 0.20. Their in-plane lattice constant increases linearly (3.111 + 0.744x A) while the out-of-plane constant remains at 4.989 {+-} 0.005 A. Optical absorption indicates a band gap of 6.15-9.32x eV and a linearly increasing density of defect states within the gap. The average bond angle decreases linearly with x, suggesting a trend towards the metastable hexagonal-ScN structure. However, an anomalous decrease at x = 0.20 indicates a structural instability which ultimately leads to phase separated rock-salt ScN grains for x > 0.4.

  3. Structural characterization and ytterbium spectroscopy in Sc{sub 2}O{sub 3} nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Galceran, M. [Fisica i Cristal.lografia de Materials i Nanomaterials (FiCMA-FiCNA), Universitat Rovira i Virgili (URV), Campus Sescelades, c/ Marcel. li Domingo, s/n, E-43007 Tarragona (Spain); Pujol, M.C., E-mail: mariacinta.pujol@urv.ca [Fisica i Cristal.lografia de Materials i Nanomaterials (FiCMA-FiCNA), Universitat Rovira i Virgili (URV), Campus Sescelades, c/ Marcel. li Domingo, s/n, E-43007 Tarragona (Spain); Carvajal, J.J.; Mateos, X. [Fisica i Cristal.lografia de Materials i Nanomaterials (FiCMA-FiCNA), Universitat Rovira i Virgili (URV), Campus Sescelades, c/ Marcel. li Domingo, s/n, E-43007 Tarragona (Spain); Zaldo, C. [Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Cientificas (CSIC), c/ Sor Juana Ines de la Cruz 3, E-28049 Madrid (Spain); Aguilo, M.; Diaz, F. [Fisica i Cristal.lografia de Materials i Nanomaterials (FiCMA-FiCNA), Universitat Rovira i Virgili (URV), Campus Sescelades, c/ Marcel. li Domingo, s/n, E-43007 Tarragona (Spain)

    2010-08-15

    Ytterbium-doped scandium oxide nanocrystals measuring less than 25 nm with compositions of Sc{sub 2-x}Yb{sub x}O{sub 3} (x=0.001-1) were prepared using the modified Pechini method. The Yb:Sc{sub 2}O{sub 3} nanocrystals were obtained by calcination at low temperature such as 1073 K for 2 h. X-ray powder diffraction (XRD) and transmission electronic microscopy (TEM) were used to perform the structural characterization of nanocrystals; these studies indicated that the nanocrystals have high crystalline quality with cubic structure and Ia3-bar space group. The morphology and particle size were studied using electron microscopy. A detailed study of the effect of the nanodimension and the ytterbium concentration on the spectroscopic characteristics of Yb{sup 3+} as an active ion was carried out in terms of optical absorption, optical emission and fluorescence decay time at room and low temperature.

  4. Recovery and purification of nickel-63 from HFIR-irradiated targets

    Energy Technology Data Exchange (ETDEWEB)

    Williams, D.F.; O`Kelley, G.D.; Knauer, J.B.; Porter, C.E.; Wiggins, J.T.

    1993-06-01

    The production of large quantities of high-specific-activity {sup 63}Ni (>10 Ci/g) requires both a highly enriched {sup 62}Ni target and a long irradiation period at high neutron flux. Trace impurities in the nickel and associated target materials are also activated and account for a significant fraction of the discharged activity and essentially all of the gamma activity. While most of these undesirable activation products can be removed as chloride complexes during anion exchange, chromium, present at {sup 51}Cr, and scandium, present as {sup 46}Sc, are exceptions and require additional processing to achieve the desired purity. Optimized flowsheets are discussed based upon the current development and production experience.

  5. Recovery and purification of nickel-63 from HFIR-irradiated targets

    Energy Technology Data Exchange (ETDEWEB)

    Williams, D.F.; O' Kelley, G.D.; Knauer, J.B.; Porter, C.E.; Wiggins, J.T.

    1993-06-01

    The production of large quantities of high-specific-activity [sup 63]Ni (>10 Ci/g) requires both a highly enriched [sup 62]Ni target and a long irradiation period at high neutron flux. Trace impurities in the nickel and associated target materials are also activated and account for a significant fraction of the discharged activity and essentially all of the gamma activity. While most of these undesirable activation products can be removed as chloride complexes during anion exchange, chromium, present at [sup 51]Cr, and scandium, present as [sup 46]Sc, are exceptions and require additional processing to achieve the desired purity. Optimized flowsheets are discussed based upon the current development and production experience.

  6. Cyclotron Produced 44gSc from Natural Calcium

    Science.gov (United States)

    Severin, G.W.; Engle, J.W.; Valdovinos, H.F.; Barnhart, T.E.; Nickles, R.J.

    2012-01-01

    44gSc was produced by 16 MeV proton irradiation of unenriched calcium metal with radionuclidic purity greater than 95%. The thick target yield at saturation for 44gSc was 213 MBq/μA, dwarfing the yields of contaminants 43Sc,44mSc, 47Sc and 48Sc for practical bombardment times of 1–2 h. Scandium was isolated from the dissolved calcium target by filtration, and reconstituted in small volumes of dilute HCl. Reactions with the chelate 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) indicated a reactivity of 54±14 Gbq/μmol at end-of-bombardment. PMID:22728844

  7. Non-noble metal based electro-catalyst compositions for proton exchange membrane based water electrolysis and methods of making

    Science.gov (United States)

    Kumta, Prashant N.; Kadakia, Karan Sandeep; Datta, Moni Kanchan; Velikokhatnyi, Oleg

    2017-02-07

    The invention provides electro-catalyst compositions for an anode electrode of a proton exchange membrane-based water electrolysis system. The compositions include a noble metal component selected from the group consisting of iridium oxide, ruthenium oxide, rhenium oxide and mixtures thereof, and a non-noble metal component selected from the group consisting of tantalum oxide, tin oxide, niobium oxide, titanium oxide, tungsten oxide, molybdenum oxide, yttrium oxide, scandium oxide, cooper oxide, zirconium oxide, nickel oxide and mixtures thereof. Further, the non-noble metal component can include a dopant. The dopant can be at least one element selected from Groups III, V, VI and VII of the Periodic Table. The compositions can be prepared using a surfactant approach or a sol gel approach. Further, the compositions are prepared using noble metal and non-noble metal precursors. Furthermore, a thin film containing the compositions can be deposited onto a substrate to form the anode electrode.

  8. Protection Against Neutron Radiation Up to 30 Million Electron Volts

    Science.gov (United States)

    1957-11-22

    5.6 Scandium 22 Selenium 1n L Silicon 0.l 1,;o Silver f;0 .2, 2.9Sodium 0.1 4.1 ɚ Strontium . 16,* Sulfur 0..1 1Tantalum . .1.3 Thallium 3.3 6.; Tin...8217ses of A tomjic Enervy. p). .35-44 (Genteva, 1955). 151I William T. Ham. .Jr.. Radiation cataract . .AMA Arch. Ophth. 50. 618-643 (195:0). I 61 P. H...Abelson and P. G. Kruger., (’ylotc-on-intlnc-d radiation cataracts . Science 10. 6551 ( 1919). 171 NBS Tech. News Pill. 11. 17 ( 19-57); Radi: I\\ ;s.r68

  9. Terbium Radionuclides for Theranostics Applications: A Focus On MEDICIS-PROMED

    Science.gov (United States)

    Cavaier, R. Formento; Haddad, F.; Sounalet, T.; Stora, T.; Zahi, I.

    A new facility, named CERN-MEDICIS, is under construction at CERN to produce radionuclides for medical applications. In parallel, the MEDICIS-PROMED, a Marie Sklodowska-Curie innovative training network of the Horizon 2020 European Commission's program, is being coordinated by CERN to train young scientists on the production and use of innovative radionuclides and develop a network of experts within Europe. One program within MEDICIS-PROMED is to determine the feasibility of producing innovative radioisotopes for theranostics using a commercial middle-sized high-current cyclotron and the mass separation technology developed at CERN-MEDICIS. This will allow the production of high specific activity radioisotopes not achievable with the common post-processing by chemical separation. Radioisotopes of scandium, copper, arsenic and terbium have been identified. Preliminary studies of activation yield and irradiation parameters optimization for the production of Tb-149 will be described.

  10. Massive stars. A chemical signature of first-generation very massive stars.

    Science.gov (United States)

    Aoki, W; Tominaga, N; Beers, T C; Honda, S; Lee, Y S

    2014-08-22

    Numerical simulations of structure formation in the early universe predict the formation of some fraction of stars with several hundred solar masses. No clear evidence of supernovae from such very massive stars has, however, yet been found in the chemical compositions of Milky Way stars. We report on an analysis of a very metal-poor star SDSS J001820.5-093939.2, which possesses elemental-abundance ratios that differ significantly from any previously known star. This star exhibits low [α-element Fe] ratios and large contrasts between the abundances of odd and even element pairs, such as scandium/titanium and cobalt/nickel. Such features have been predicted by nucleosynthesis models for supernovae of stars more than 140 times as massive as the Sun, suggesting that the mass distribution of first-generation stars might extend to 100 solar masses or larger. Copyright © 2014, American Association for the Advancement of Science.

  11. Development of Cr,Nd:GSGG laser as a pumping source of Ti:sapphire laser

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, Koji [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Arisawa, Takashi

    1999-08-01

    Since efficiency of Cr,Nd doped gadolinium scandium gallium garnet (GSGG) laser is in principle higher than that of Nd:YAG laser, it can be a highly efficient pumping source for Ti:sapphire laser. We have made GSGG laser, and measured its oscillation properties. It was two times more efficient than Nd:YAG laser at free running mode operation. At Q-switched mode operation, fundamental output of 50 mJ and second harmonics output of 8 mJ were obtained. The developed laser had appropriate spatial profile, temporal duration, long time stability for solid laser pumping. Ti:sapphire laser oscillation was achieved by the second harmonics of GSGG laser. (author)

  12. Mechanical property evaluations of an amorphous metallic/ceramic multilayer and its role in improving fatigue properties of 316L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Cheng-Min [Nano Technology Center, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Jeng, R.J.; Yu, Chia-Chi; Chang, Chia-Hao [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Li, Chia-Lin [Department of Materials Science and Engineering and Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Chu, Jinn P., E-mail: jpchu@mail.ntust.edu.tw [Nano Technology Center, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China)

    2016-08-01

    We have used nanoindentation to investigate mechanical properties of 200-nm-thick amorphous multilayer consisting of alternating layers of Zr-based thin film metallic glass (TFMG) and holmium scandium oxide (HSO). Nanoindentation results show that TFMG/HSO multilayer exhibits the high hardness and Young's modulus. Owing to its high hardness, smooth surface, and good adhesion properties, TFMG/HSO multilayer is then employed as a protective coating to improve the four-point bending fatigue properties of 316L stainless steel. With coating, the fatigue life is increased from 2.4×10{sup 5} to 4.9×10{sup 6} cycles, at the stress of 700 MPa. A crack retardation mechanism has been proposed to explain the role of TFMG/HSO multilayer in improving fatigue properties of 316L stainless steel substrate.

  13. Clinical, morphological, and ultrastructural aspects with the use of Er:YAG and Er,Cr:YSGG lasers in restorative dentistry.

    Science.gov (United States)

    Iaria, Giuseppe

    2008-01-01

    The Er:YAG laser has an active medium of Yttrium-Aluminium-Garnet doped with Erbium ions and emits free-running pulsed laser energy at a wavelength of 2940 nm. The Er,Cr:YSGG laser has an active medium of Yttrium-Scandium-Gallium-Garnet doped with Erbium and Chromium ions and emits free-running pulsed laser energy at a wavelength of 2780 nm. These wavelengths have a high absorption in water, which makes their application appropriate for ablating oral soft tissue as well as dental hard tissue. This article examines the principles of use for the Er:YAG and Er,Cr:YSGG lasers in clinical restorative dentistry and reviews the literature regarding different aspects of the use of laser energy on hard tissues.

  14. The high-temperature modification of ScRuSi - Structure, 29Si and 45Sc solid state NMR spectroscopy

    Science.gov (United States)

    Hoffmann, Rolf-Dieter; Rodewald, Ute Ch.; Haverkamp, Sandra; Benndorf, Christopher; Eckert, Hellmut; Heying, Birgit; Pöttgen, Rainer

    2017-10-01

    A polycrystalline sample of the TiNiSi type low-temperature (LT) modification of ScRuSi was synthesized by arc-melting. Longer annealing in a sealed silica tube (6 weeks at 1270 K) followed by quenching led to the high-temperature (HT) phase. HT-ScRuSi adopts the ZrNiAl structure type: P 6 bar 2 m , a = 688.27(9), c = 336.72(5) pm, wR2 = 0.0861, 260 F2 values, 14 variables. The striking structural building units are regular, tricapped trigonal prisms Si1@Ru3Sc6 and Si2@Ru6Sc3. Both polymorphs have been characterized by 29Si and 45Sc MAS-NMR spectroscopy. The local scandium environments in the two polymorphs are easily distinguished by their electric field gradient tensor values, in agreement with theoretically calculated values.

  15. Undercooling of Rapidly Solidified Droplets and Spray Formed Strips of Al-Cu (Sc)

    Science.gov (United States)

    Bogno, A.; Natzke, P.; Yin, S.; Henein, H.

    Impulse Atomization (IA) (a single fluid atomization technique) was used to rapidly solidify Al-4.5wt%Cu and Al-4.5wt%Cu-0.4wt%Sc under argon atmosphere. In addition to the IA-generated droplets, the same technique was used to produce strips by Spray Deposition (SD) of the same alloys on a copper substrate with and without oil coating. The rapid solidification microstructures were analyzed using Scanning Electron Microscopy (SEM). From the SEM images, the amount of eutectic and the secondary dendrite arm spacing (SDAS) were measured. These SDAS results lead to the estimation of cooling rate. The eutectic fraction coupled with the metastable extension of the solidus and liquidus lines of Al-Cu (Sc) phase diagram lead to the estimation of primary and eutectic undercoolings. A comparison of the solidification path of the droplets and the strips was done as well as the analysis of the effects of scandium.

  16. Advancing Chemistry with the Lanthanide and Actinide Elements: Final Report, September 2013

    Energy Technology Data Exchange (ETDEWEB)

    Evans, William John [Univ. of California, Irvine, CA (United States). Dept. of Chemistry

    2013-09-11

    The objective of this research is to use the unique chemistry available from complexes of the lanthanides and actinides, as well as related heavy metals such as scandium, yttrium, and bismuth to advance chemistry in energy-related areas. The lanthanides and actinides have a combination of properties in terms of size, charge, electropositive character, and f valence orbitals that provides special opportunities to probe reactivity and catalysis in ways not possible with the other metals in the periodic table. We seek to discover reaction pathways and structural types that reveal new options in reaction chemistry related to energy. Identification of new paradigms in structure and reactivity should stimulate efforts to develop new types of catalytic processes that at present are not under consideration because either the transformation or the necessary intermediates are unknown.

  17. Technologic advances in endodontics.

    Science.gov (United States)

    Mortman, Rory E

    2011-07-01

    This article addresses technologic advances in endodontics pertaining to new and emerging technology. Cone-beam computed tomography and optical occurrence tomography are 2 new imaging technologies that can assist the practitioner in the diagnosis of pulpal disease. The self-adjusting file and the Apexum device can be used for instrumentation and bulk debridement of an apical lesion, respectively. Neodymium:yttrium-aluminum-garnet laser, erbium:chromium:yttrium-scandium-gallium-garnet laser, EndoActivator, EndoVac, and light-activated disinfection may assist the practitioner in cleaning the root canal system. Computed tomography-guided surgery shows promise in making endodontic surgery easier, as does mineral trioxide aggregate cement for regenerative endodontic procedures. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Microstructure and high temperature stability of age hardenable AA2219 aluminium alloy modified by Sc, Mg and Zr additions

    Energy Technology Data Exchange (ETDEWEB)

    Naga Raju, P. [Metallurgical and Materials Engineering Department, IIT-Madras, Chennai 600036 (India)], E-mail: puvvala_nagaraju@yahoo.com; Srinivasa Rao, K. [Metallurgical Engineering Department, Andhra University, Visakapatnam 530003 (India); Reddy, G.M. [Defence Metallurgical Research Laboratory, Hyderabad 500258 (India); Kamaraj, M.; Prasad Rao, K. [Metallurgical and Materials Engineering Department, IIT-Madras, Chennai 600036 (India)

    2007-08-25

    The present work pertains to the improvement of high temperature stability of age hardenable AA2219 aluminium-copper (6.3%) alloy. Addition of scandium, magnesium and zirconium to the base metal AA2219 was adopted to improve this high temperature stability. These additions were systematically varied by preparing alloys of different composition using gas tungsten arc melting. Long time ageing studies and impression creep technique were used to study the high temperature stability of the alloys. These modified compositions of the alloy resulted in fine equiaxed grains, refined eutectics, large number of high temperature stable and finer precipitates. Among all the compositions, 0.8% Sc + 0.45% Mg + 0.2% Zr addition was found to be significant in improving the high temperature stability of AA2219 alloy. This may be attributed to the possible microstructural changes, solute enrichment of the matrix and pinning of the grain boundaries by the finer precipitates.

  19. Sustainability of rare earth elements chain: from production to food - a review.

    Science.gov (United States)

    Turra, Christian

    2017-12-15

    Rare earth elements (REE) are a group of chemical elements that include lanthanoids (lanthanum to lutetium), scandium and yttrium. In the last decades, the REE demand in the industry and other areas has increased significantly. In general, REE have shown low concentrations in soils, plants, water and atmosphere, but they may accumulate in such environments due to anthropogenic inputs. In areas where there is REE contamination, the slow accumulation of these elements in the environment could become problematic. Many studies have shown environmental areas contaminated with REE and their toxic effects. Thus, it is important to review, in order to improve the current understanding of these elements in the environment, showing the effects of REE exposure in mining, soil, water, plants and food. Besides, there are few suppliers and a limited quantity of these elements in the world. This paper suggests options to improve the sustainability management of REE chain.

  20. New electron spin resonance and mass spectrometric studies of metallofullerenes

    Science.gov (United States)

    Bartl, A.; Dunsch, L.; Froehner, J.; Kirbach, U.

    1994-10-01

    The preparation by arc vaporization of graphite rods of metal-containing fullerene samples with metals inside the fullerene molecules is described. The metals lanthanum, scandium, holmium and yttrium were used for this study. Results in mass spectrometry confirm the existence and stability of several Me at C82 species. Electron spin resonance (ESR) spectroscopic measurements of metallofullerene samples in the solid state and in tetrachloroethane solution favor the existence of endohedral systems. The splitting of the ESR spectra is interpreted by isotropic hyperfine coupling of an unpaired electron with the nuclear magnetic moment of a metal ion inside a fullerene molecule. It is concluded that the metal atoms exist in ionic form in endohedral fullerenes both in solid and liquid state of the fullerene. Furthermore it is shown that there is more than one stable position of the metal ion inside the fullerene molecule.

  1. Analysis of inorganic and organic constituents of myrrh resin by GC–MS and ICP-MS: An emphasis on medicinal assets

    Directory of Open Access Journals (Sweden)

    Syed Rizwan Ahamad

    2017-07-01

    Full Text Available The aim of the present investigation was to explore the constituents of the Arabian myrrh resin obtained from Commiphora myrrha. The organic and inorganic composition of the myrrh gum resin has been investigated using gas chromatography-mass spectrometry (GC–MS and inductively coupled plasma-mass spectrometry (ICP-MS. Analysis executed by ICP-MS reveals the presence of various inorganic elements in significant amount in the myrrh resin. The elements that were found to be present in large amounts include calcium, magnesium, aluminum, phosphorus, chlorine, chromium, bromine and scandium. The important organic constituents identified in the myrrh ethanolic extract include limonene, curzerene, germacrene B, isocericenine, myrcenol, beta selinene, and spathulenol,. The present work complements other myrrh associated investigations done in the past and provides additional data for the future researches.

  2. The coloring problem in the solid-state metal boride carbide ScB{sub 2}C{sub 2}. A theoretical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lassoued, Souheila [Universite de Rennes, Ecole Nationale Superieure de Chimie, UMR 6226 CNRS (France). Inst. des Sciences Chimiques; Universite Kasdi Merbah-Ouargla (Algeria). Faculte des Mathematiques et des Sciences de la Matiere; Boucher, Benoit [Universite de Rennes, Ecole Nationale Superieure de Chimie, UMR 6226 CNRS (France). Inst. des Sciences Chimiques; Max-Planck-Institut fuer Chemische Physik Fester Stoffe, Dresden (Germany); Boutarfaia, Ahmed [Universite Kasdi Merbah-Ouargla (Algeria). Faculte des Mathematiques et des Sciences de la Matiere; Gautier, Regis; Halet, Jean-Francois [Universite de Rennes, Ecole Nationale Superieure de Chimie, UMR 6226 CNRS (France). Inst. des Sciences Chimiques

    2016-08-01

    The electronic properties of the layered ternary metal boride carbide ScB{sub 2}C{sub 2}, the structure of which consists of B/C layers made of fused five- and seven-membered rings alternating with scandium sheets, are analyzed. In particular, the respective positions of the B and C atoms (the so-called coloring problem) are tackled using density functional theory, quantum theory of atoms in molecules, and electron localizability indicator calculations. Results reveal that (i) the most stable coloring minimizes the number of B-B and C-C contacts and maximizes the number of boron atoms in the heptagons, (ii) the compound is metallic in character, and (iii) rather important covalent bonding occurs between the metallic sheets and the boron-carbon network.

  3. Density functional study of AgScO_2: Electronic and optical properties

    Science.gov (United States)

    Bhamu, K. C.; Sahariya, Jagrati; Vyas, Rishi; Priolkar, K. R.

    2017-07-01

    This paper focusses on the electronic and optical properties of scandium-based silver delafossite (AgScO_2) semiconductor. The density functional theory (DFT) in the framework of full potential linearized augmented plane wave (FP-LAPW) scheme has been used for the present calculations with local density approximation (LDA) and generalized gradient approximation (GGA). Electronic properties deal with energy bands and density of states (DOSs), while optical properties describe refractive index and absorption coefficient. The energy bands are interpreted in terms of DOSs. The computed value of band gap is in agreement with that reported in the literature. Our results predict AgScO_2 as indirect band-gap semiconductor. Our calculated value of the refractive index in zero frequency limits is 2.42. The absorption coefficient predicts the applicability of AgScO_2 in solar cells and flat panel liquid crystal display as a transparent top window layer.

  4. Oxidation of zirconium alloys in 2.5 kPa water vapor for tritium readiness.

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Bernice E.

    2007-11-01

    A more reactive liner material is needed for use as liner and cruciform material in tritium producing burnable absorber rods (TPBAR) in commercial light water nuclear reactors (CLWR). The function of these components is to convert any water that is released from the Li-6 enriched lithium aluminate breeder material to oxide and hydrogen that can be gettered, thus minimizing the permeation of tritium into the reactor coolant. Fourteen zirconium alloys were exposed to 2.5 kPa water vapor in a helium stream at 300 C over a period of up to 35 days. Experimental alloys with aluminum, yttrium, vanadium, titanium, and scandium, some of which also included ternaries with nickel, were included along with a high nitrogen impurity alloy and the commercial alloy Zircaloy-2. They displayed a reactivity range of almost 500, with Zircaloy-2 being the least reactive.

  5. Laser systems for ablative fractional resurfacing

    DEFF Research Database (Denmark)

    Paasch, Uwe; Haedersdal, Merete

    2011-01-01

    Ablative fractional resurfacing (AFR) creates microscopic vertical ablated channels that are surrounded by a thin layer of coagulated tissue, constituting the microscopic treatment zones (MTZs). AFR induces epidermal and dermal remodeling, which raises new possibilities for the treatment of a var......Ablative fractional resurfacing (AFR) creates microscopic vertical ablated channels that are surrounded by a thin layer of coagulated tissue, constituting the microscopic treatment zones (MTZs). AFR induces epidermal and dermal remodeling, which raises new possibilities for the treatment...... ablative laser systems. Fractionated CO(2) (10,600-nm), erbium yttrium aluminum garnet, 2940-nm and yttrium scandium gallium garnet, 2790-nm lasers are available. In this article, we present an overview of AFR technology, devices and histopathology, and we summarize the current clinical possibilities...

  6. Historical economic and environmental policies influencing trace metal inputs in Montevideo Bay, Río de la Plata.

    Science.gov (United States)

    Bueno, C; Brugnoli, E; Figueira, R C L; Muniz, P; Ferreira, P A L; García Rodríguez, F

    2016-12-15

    Montevideo Bay is located in the middle zone of the Rio de la Plata, and since the foundation of the city, several key economic and environmental policies affected the industry, and thus, metal inputs into this ecosystem. The aim of this study is to evaluate the sedimentary geochemical record of Montevideo Bay, in order to determine the historical inputs of anthropogenic metals to the system. In addition, environmental and economic policies of the country were taken into account to infer the relationship between them and the historic metal input. Concentrations of aluminum, chromium, copper, lead, scandium and zinc were analyzed and the EF and SPI indices were calculated. The analysis showed that since Montevideo foundation, metal concentrations increased in accordance with industry development, and the indices as well as the metal concentration represent a reliable footprint of the history of different economic and environmental policies influencing historical industrial activities. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Precipitation Reactions in Age-Hardenable Alloys During Laser Additive Manufacturing

    Science.gov (United States)

    Jägle, Eric A.; Sheng, Zhendong; Wu, Liang; Lu, Lin; Risse, Jeroen; Weisheit, Andreas; Raabe, Dierk

    2016-03-01

    We describe and study the thermal profiles experienced by various age-hardenable alloys during laser additive manufacturing (LAM), employing two different manufacturing techniques: selective laser melting and laser metal deposition. Using scanning electron microscopy and atom probe tomography, we reveal at which stages during the manufacturing process desired and undesired precipitation reactions can occur in age-hardenable alloys. Using examples from a maraging steel, a nickel-base superalloy and a scandium-containing aluminium alloy, we demonstrate that precipitation can already occur during the production of the powders used as starting material, during the deposition of material (i.e. during solidification and subsequent cooling), during the intrinsic heat treatment effected by LAM (i.e. in the heat affected zones) and, naturally, during an ageing post-heat treatment. These examples demonstrate the importance of understanding and controlling the thermal profile during the entire additive manufacturing cycle of age-hardenable materials including powder synthesis.

  8. Determination of metallic impurities in raw materials for radioisotope production by atomic absorption spectroscopy; Determinacion de trazas metalicas en amterias primas para la produccion de radioisotopos por espectroscopia de absorcion atomica

    Energy Technology Data Exchange (ETDEWEB)

    Roca, M.; Alvarez, F.; Capdevila, C.

    1969-07-01

    Atomic absorption spectrometry has been used for the determination of traces of calcium in scandium oxide, copper in zinc, iron in cobalt oxide, manganese In ferric oxide, nickel in copper and zinc in gallium oxide. The influences on the sensitivities arising from the hollow cathode currents, the gas pressures and the acid concentrations have been considered. A study of the interferences from the metallic matrices has also been performed, the interference due to the absorption of the manganese radiation by the atoms of iron being the most outstanding . In order to remove the interfering elements and increase sensitivity, pre-concentration methods have been tested. The addition methods has also been used. (Author) 14 refs.

  9. Dynamic Covalent Assembly of Peptoid-Based Ladder Oligomers by Vernier Templating.

    Science.gov (United States)

    Wei, Tao; Jung, Jae Hwan; Scott, Timothy F

    2015-12-30

    Dynamic covalent chemistry, in conjunction with template-directed assembly, enables the fabrication of extended nanostructures that are both precise and tough. Here we demonstrate the dynamic covalent assembly of peptoid-based molecular ladders with up to 12 rungs via scandium(III)-catalyzed imine metathesis by employing the principle of Vernier templating, where small precursor units with mismatched numbers of complementary functional groups are coreacted to yield larger structures with sizes determined by the respective precursor functionalities. Owing to their monomer diversity and synthetic accessibility, sequence-specific oligopeptoids bearing dynamic covalent pendant groups were employed as precursors for molecular ladder fabrication. The generated structures were characterized using matrix-assisted laser desorption/ionization mass spectrometry and gel permeation chromatography, confirming successful molecular ladder fabrication.

  10. Measurement of (n,2n) cross-sections for Sc, Mn, Cr and In between 12 and 19 MeV with activation technique

    Energy Technology Data Exchange (ETDEWEB)

    Iwasaki, S.; Win, Than; Matsuyama, S. [Tohoku Univ., Sendai (Japan). Faculty of Engineering; Odano, N.

    1997-03-01

    Activation cross-sections for scandium, manganese, chromium and indium have been measured in the neutron energies from 12 to 19 MeV. Source neutrons were produced via the T(d,n){sup 4}He reaction by bombarding a 3.2-MeV deuteron beam from the Dynamitron accelerator of Fast Neutron Laboratory at Tohoku University. Ten packages of high or ultra-high purity metal foils for chromium and indium, alloy foils for manganese, and oxide powder for scandium were set around the neutron source at 5 cm from the target in the angular range from 0 to 140 deg covering the incident neutron energies from 19 to 12 MeV at the center position of each package. Activation rates of the samples were obtained by the gamma-ray measurements using a high purity germanium detector. Neutron flux at each sample was determined using the activation rates of two niobium foils locating both sides of that sample; the reference reaction was {sup 93}Nb(n,2n){sup 92m}Nb of which cross-section data was taken from the 1991 NEANDC/INDC standard files. The source neutrons distributions have been measured in detail by the time-of-flight technique. The measured cross-sections are the following important dosimetry or activation reactions: {sup 45}Sc(n,2n){sup 44m}Sc, {sup 55}Mn(n,2n){sup 54}Mn, {sup 52}Cr(n,2n){sup 51}Cr, and {sup 115}In(n,2n){sup 114m}In. These cross-sections are compared with available activation file, dosimetry files and previous experimental data. (author)

  11. Epitaxial growth of Sc-doped ZnO films on Si by sol-gel route

    Science.gov (United States)

    Sharma, Ruchika; Sehrawat, Kiran; Wakahara, Akihiro; Mehra, R. M.

    2009-03-01

    The epitaxial growth of doped ZnO films is of great technological importance. Present paper reports a detailed investigation of Sc-doped ZnO films grown on (1 0 0) silicon p-type substrates. The films were deposited by sol-gel technique using zinc acetate dihydrate as precursor, 2-methoxyethanol as solvent and monoethanolamine (MEA) as a stabilizer. Scandium was introduced as dopant in the solution by taking 0.5 wt% of scandium nitrate hexahydrate. The effect of annealing on structural and photoluminescence properties of nano-textured Sc-doped films was investigated in the temperature range of 300-550 °C. Structural investigations were carried out using X-ray diffraction, scanning electron microscopy and atomic force microscopy. X-ray diffraction study revealed that highly c-axis oriented films with full-width half maximum of 0.21° are obtained at an annealing temperature of 400 °C. The SEM images of ZnO:Sc films have revealed that coalescence of ZnO grains occurs due to annealing. Ostwald ripening was found to be the dominant mass transport mechanism in the coalescence process. A surface roughness of 4.7 nm and packing density of 0.93 were observed for the films annealed at 400 °C. Room temperature photoluminescence (PL) measurements of ZnO:Sc films annealed at 400 °C showed ultraviolet peak at about (382 nm) with FWHM of 141 meV, which are comparable to those found in high-quality ZnO films. The films annealed below or above 400 °C exhibited green emission as well. The presence of green emission has been correlated with the structural changes due to annealing. Reflection high energy electron diffraction pattern confirmed the nearly epitaxial growth of the films. Ruchika Sharma, P. K. Shishodia, A. Wakahara and R. M. Mehra, Materials Science-Poland 27 (2009) Ist issue.

  12. New insights on cytotoxic activity of group 3 and lanthanide compounds: complexes with [N,N,N]-scorpionate ligands.

    Science.gov (United States)

    Saturnino, Carmela; Bortoluzzi, Marco; Napoli, Mariagrazia; Popolo, Ada; Pinto, Aldo; Longo, Pasquale; Paolucci, Gino

    2013-09-01

    In this work was to evaluate the cytotoxic activity of a series of monomeric group 3 and lanthanide (N,N,N)-heteroscorpionate-triflate complexes (M (OTf) 2 (cybpamd) (THF)) (Ln = Sc (2), Y (3), La (4), Nd (5), Sm (6), Dy (7), Yb (8); OTf = SO3CF3; cybpamd = N, N'-dicyclohexyl-2,2-bis-(3,5-dimethyl-pyrazol-1-yl)-acetamidinate) having octahedral geometry around the metal atoms on the human epithelial lung adenocarcinoma (A549), human melanoma (A375), human cervical epithelial adenocarcinoma, human embryonic kidney (HEK-293) and murine macrophages (J774.A1) cell lines. All the tested compounds were incubated with cells for 72 h and their growth inhibition assessed by using MTT assay. On the cell line HEK-293 complexes 5 and 7 show a reasonable activities, while the murine macrophage cell line (J774.A1), only the scandium 2 complex is not very active. All complexes tested are poorly active on human health adenocarcinoma lung epithelial (A549) and human melanoma (A375). The group 3 and lanthanide (N,N,N)-heteroscorpionate triflate-complexes (M(OTf)2(cybpamd)(THF)) on murine macrophage (J774.A1) cell line, except that of scandium, show a reasonable activity. On human epithelial cervix adenocarcinoma (HeLa) complexes 3, 5 and 6 are significantly more active than cis-platinum, as well as complex 5 is more active on human embryonic kidney (HEK-293) cell line. All the tested complexes are poorly active on human epithelial lung adenocarcinoma (A549) and human melanoma (A375). The different behaviour of the complexes examined (2-8) let us hypothesize that the cytotoxic activity is related to the molecule as a whole and not only to the ligand or the metal ion separately. © 2013 Royal Pharmaceutical Society.

  13. Influence of N{sub 2}/Ar-flow ratio on crystal quality and electrical properties of ScAlN thin film prepared by DC reactive magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jian-cang, E-mail: jcyang58@163.com; Meng, Xiang-qin; Yang, Cheng-tao; Fu, Wu-jun

    2013-10-01

    Scandium aluminum nitride alloy (ScAlN) thin films were prepared using DC reactive magnetron sputtering with a scandium aluminum alloy (Sc{sub 0.06}Al{sub 0.94}) target on n-type silicon substrates. We have investigated the influence of N{sub 2}/Ar-flow ratio on the crystalline structure, the surface morphology and the electrical properties of ScAlN thin films. Consequently, it was statistically proved that the N{sub 2}/Ar-flow ratio was an important control factor in the process of sputtering. According to the peak intensities in θ/2θ scans and rocking curve FWHM measurements of the (0 0 2) peaks, the crystalline quality of ScAlN thin film first increased and then decreased, reaching the best crystalline state at a N{sub 2}/Ar-flow ratio of 3.3:7. The best surface morphology of ScAlN thin film was obtained at N{sub 2}/Ar-flow ratios of 3.2:7, 3.3:7 and 3.4:7 and the surface roughness reached a minimum of 2.612 nm at 3.3:7. The resistivity and dielectric constant first increased to maximum values of 3.35 × 10{sup 12} Ω cm and 13.6, and then decreased with the ratio increasing. Moreover, ScAlN thin film exhibited a higher value of resistivity and dielectric constant when compared with un-doped AlN thin film. In addition, when the N{sub 2}/Ar-flow ratio was 3.3:7, the highest breakdown field strength and lowest leakage current were obtained, with values 1.12 MV/cm and 3 × 10{sup −8} A, respectively.

  14. Influence of sputtering power on crystal quality and electrical properties of Sc-doped AlN film prepared by DC magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jian-cang, E-mail: jcyang58@163.com; Meng, Xiang-qin; Yang, Cheng-tao; Zhang, Yao

    2013-12-15

    Scandium-doped aluminum nitride alloy (ScAlN) thin films were deposited on (1 0 0) silicon substrates by DC reactive magnetron sputtering method using a scandium aluminum alloy (Sc{sub 0.06}Al{sub 0.94}) target. The influence of sputtering power on the crystalline structure, surface morphology and electrical properties of ScAlN thin films were investigated. The XRD patterns indicated all the films showed a single pronounced hexagonal (0 0 2) peak. According to the peak intensities in θ/2θ scans and rocking curve FWHM measurements of the (0 0 2) peaks, the crystalline quality of ScAlN thin film first increased and then decreased, reaching the best crystalline state at a sputtering power of 130 W. The best surface morphology of ScAlN thin film was obtained at 130 W and the surface roughness reached a minimum of 2.612 nm. Then the piezoelectric response of ScAlN thin films was measured and the highest value, 8.9 pC/N, was achieved at the sample with the best crystal quality. The resistivity and dielectric constant change in the same rule as the crystal quality, first increasing to a maximum value of 3.35 × 10{sup 12} Ω cm and 13.6, and then decreasing with the sputtering power increasing. In addition, when the sputtering power was 130 W, the highest breakdown field strength and lowest leakage current were obtained, with values 1.12 MV/cm and 3 × 10{sup −8} A, respectively.

  15. Increasing atmospheric antimony contamination in the northern hemisphere: snow and ice evidence from Devon Island, Arctic Canada.

    Science.gov (United States)

    Krachler, Michael; Zheng, James; Koerner, Roy; Zdanowicz, Christian; Fisher, David; Shotyk, William

    2005-12-01

    Adopting recently developed clean laboratory techniques, antimony (Sb) and scandium (Sc) deposition were measured in a 63.72 m-long ice core (1842-1996) and a 5 m deep snow pit (1994-2004) collected on Devon Island, Canadian High Arctic. Antimony concentrations ranged from 0.07 to 108 pg g(-1) with a median of 0.98 pg g(-1)(N= 510). Scandium, used as a conservative reference element, revealed that dust inputs were effectively constant during the last 160 years. The atmospheric Sb signal preserved in the ice core reflects contamination from industrialisation, the economic boom which followed WWII, as well as the comparatively recent introduction of flue gas filter technologies and emission reduction efforts. Natural contributions to the total Sb inventory are negligible, meaning that anthropogenic emissions have dominated atmospheric Sb deposition throughout the entire period. The seasonal resolution of the snow pit showed that aerosols deposited during the Arctic winter, when air masses are derived mainly from Eurasia, show the greatest Sb concentrations. Deposition during summer, when air masses come mainly from North America, is still enriched in Sb, but less so. Snow and ice provide unambiguous evidence that enrichments of Sb in Arctic air have increased 50% during the past three decades, with two-thirds being deposited during winter. Most Sb is produced in Asia, primarily from Sb sulfides such as stibnite (Sb2S3), but also as a by-product of lead and copper smelting. In addition there is a growing worldwide use of Sb in automobile brake pads, plastics and flame retardants. In contrast to Pb which has gone into decline during the same interval because of the gradual elimination of gasoline lead additives, the enrichments of Sb have been increasing and today clearly exceed those of Pb. Given that the toxicity of Sb is comparable to that of Pb, Sb has now replaced Pb in the rank of potentially toxic trace metals in the Arctic atmosphere.

  16. CW ESR studies on endohedral fullerenes

    Science.gov (United States)

    Bartl, Anton; Dunsch, Lothar; Kirbach, Uwe

    1996-12-01

    Electron spin resonance (ESR) spectroscopy is used in this study in connection with the mass spectrometry one of the most promising method to characterize the state of endohedral fullerenes. The aim of this contribution is to study scandium, yttrium, lanthanum, cerium, praseodymium, samarium, europium, holmium, thulium and lutetium containing fullerenes in dependence on the production and handling conditions with respect to their electronic structure. For the most metallofullerenes both single filled and double filled fullerenes were measured. The mass spectrometric signals of single filled fullerenes are much larger than the signals of double and higher filled metallofullerenes. ESR spectroscopic properties were followed especially in solution of isolated metallofullerenes of high purity characterized by well resolved ESR spectra but also of the solid soot extract resulting in low resolved ESR spectra. In this way new information on the electronic states and the influence of oxygen on endohedral metallofullerene were obtained. The interaction of the lanthanofullerence with oxygen is studied in detail. Different stabilities in different solvents in the presence of oxygen were found for La at C82 molecules. For scandium, yttrium and lanthanum containing fullerenes ESR spectra with hyperfine structure splittings corresponding to the nuclear spin of the metal ion were found. Experiments with lanthanoides results in fullerenes, showing mass spectra with lines equivalent to the corresponding endohedral compounds with single and double filed cages, but no ESR spectra due to the interaction of an unpaired electron with the nuclear spin of the lanthanoide ion could be detected in the magnetic field range of 0 to 800 mT.

  17. Interaction of coal-derived synthesis gas impurities with solid oxide fuel cell metallic components

    Energy Technology Data Exchange (ETDEWEB)

    Marina, Olga A.; Coyle, Christopher A.; Edwards, Danny J.; Chou, Yeong-Shyung; Cramer, Carolyn N. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Pederson, Larry R. [North Dakota State University, Fargo, ND 58102 (United States)

    2011-01-15

    Oxidation-resistant alloys find use as interconnect materials, heat exchangers, and gas supply tubing in solid oxide fuel cell (SOFC) systems, especially when operated at temperatures below {proportional_to}800 C. If fueled with synthesis gas derived from coal or biomass, such metallic components could be exposed to impurities contained in those fuel sources. In this study, coupons of ferritic stainless steels Crofer 22 APU and SS 441, austenitic nickel-chromium superalloy Inconel 600, and an alumina-forming high nickel alloy alumel were exposed to synthesis gas containing {<=}2 ppm phosphorus, arsenic and antimony, and reaction products were tested. Crofer 22 APU coupons coated with a (Mn,Co){sub 3}O{sub 4} protective layer were also evaluated. Phosphorus was found to be the most reactive. On Crofer 22 APU, the (Mn,Cr){sub 3}O{sub 4} passivation layer reacted to form an Mn-P-O product, predicted to be manganese phosphate from thermochemical calculations, and Cr{sub 2}O{sub 3}. On SS 441, reaction of phosphorus with (Mn,Cr){sub 3}O{sub 4} led to the formation of manganese phosphate as well as an Fe-P product, predicted from thermochemical calculations to be Fe{sub 3}P. Minimal interactions with antimony or arsenic in synthesis gas were limited to Fe-Sb and Fe-As solid solution formation. Though not intended for use on the anode side, a (Mn,Co){sub 3}O{sub 4} spinel coating on Crofer 22 APU reacted with phosphorus in synthesis gas to produce products consistent with Mn{sub 3}(PO{sub 4}){sub 2} and Co{sub 2}P. A thin Cr{sub 2}O{sub 3} passivation layer on Inconel 600 did not prevent the formation of nickel phosphides and arsenides and of iron phosphides and arsenides, though no reaction with Cr{sub 2}O{sub 3} was apparent. On alumel, an Al{sub 2}O{sub 3} passivation layer rich in Ni did not prevent the formation of nickel phosphides, arsenides, and antimonides, though no reaction with Al{sub 2}O{sub 3} occurred. This work shows that unprotected metallic components of

  18. III-Vs at Scale: A PV Manufacturing Cost Analysis of the Thin Film Vapor-Liquid-Solid Growth Mode

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Maxwell; Horowitz, Kelsey; Woodhouse, Michael; Battaglia, Corsin; Kapadia, Rehan; Javey, Ali

    2016-06-01

    The authors present a manufacturing cost analysis for producing thin-film indium phosphide modules by combining a novel thin-film vapor-liquid-solid (TF-VLS) growth process with a standard monolithic module platform. The example cell structure is ITO/n-TiO2/p-InP/Mo. For a benchmark scenario of 12% efficient modules, the module cost is estimated to be $0.66/W(DC) and the module cost is calculated to be around $0.36/W(DC) at a long-term potential efficiency of 24%. The manufacturing cost for the TF-VLS growth portion is estimated to be ~$23/m2, a significant reduction compared with traditional metalorganic chemical vapor deposition. The analysis here suggests the TF-VLS growth mode could enable lower-cost, high-efficiency III-V photovoltaics compared with manufacturing methods used today and open up possibilities for other optoelectronic applications as well.

  19. Integration, gap formation, and sharpening of III-V heterostructure nanowires by selective etching

    DEFF Research Database (Denmark)

    Kallesoe, C.; Mølhave, Kristian; Larsen, K. F.

    2010-01-01

    Epitaxial growth of heterostructure nanowires allows for the definition of narrow sections with specific semiconductor composition. The authors demonstrate how postgrowth engineering of III-V heterostructure nanowires using selective etching can form gaps, sharpening of tips, and thin sections...... simultaneously on multiple nanowires. They investigate the potential of combining nanostencil deposition of catalyst, epitaxial III-V heterostructure nanowire growth, and selective etching, as a road toward wafer scale integration and engineering of nanowires with existing silicon technology. Nanostencil...... lithography is used for deposition of catalyst particles on trench sidewalls and the lateral growth of III-V nanowires is achieved from such catalysts. The selectivity of a bromine-based etch on gallium arsenide segments in gallium phosphide nanowires is examined, using a hydrochloride etch to remove the III...

  20. Pressure effects on the elastic and lattice dynamics properties of AlP from first-principles calculations

    Science.gov (United States)

    Lakel, S.; Okbi, F.; Ibrir, M.; Almi, K.

    2015-03-01

    We have performed first-principles calculations to investigate the behavior under hydrostatic pressure of the structural, elastic and lattice dynamics properties of aluminum phosphide crystal (AlP), in both zinc-blende (B3) and nickel arsenide (B8) phases. Our calculated structural and electronic properties are in good agreement with previous theoretical and experimental results. The elastic constants, bulk modulus (B), shear modulus (G), and Young's modulus (E), Born effective charge and static dielectric constant ɛ0, were calculated with the generalized gradient approximations and the density functional perturbation theory (DFPT). Our results in the pressure behavior of the elastic and dielectric properties of both phases are compared and contrasted with the common III-V materials. The Born effective charge ZB decreases linearly with pressure increasing, while the static dielectric constant decreases quadratically with the increase of pressure.

  1. High-Performance Rh 2 P Electrocatalyst for Efficient Water Splitting

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Haohong [Department; Chemistry; Li, Dongguo [Materials; Tang, Yan [Department; amp, Molecular; He, Yang [Department; Ji, Shufang [Department; Wang, Rongyue [Materials; Lv, Haifeng [Materials; Lopes, Pietro P. [Materials; Paulikas, Arvydas P. [Materials; Li, Haoyi [Department; amp, Molecular; Mao, Scott X. [Department; Wang, Chongmin [Environmental; Markovic, Nenad M. [Materials; Li, Jun [Department; amp, Molecular; Stamenkovic, Vojislav R. [Materials; Li, Yadong [Department

    2017-04-05

    The search for active, stable, and cost-efficient electrocatalysts for hydrogen production via water splitting could make a substantial impact on energy technologies that do not rely on fossil fuels. Here we report the synthesis of rhodium phosphide electrocatalyst with low metal loading in the form of nanocubes (NCs) dispersed in high-surface-area carbon (Rh2P/C) by a facile solvo-thermal approach. The Rh2P/C NCs exhibit remarkable performance for hydrogen evolution reaction and oxygen evolution reaction compared to Rh/C and Pt/C catalysts. The atomic structure of the Rh2P NCs was directly observed by annular dark-field scanning transmission electron microscopy, which revealed a phosphorus-rich outermost atomic layer. Combined experimental and computational studies suggest that surface phosphorus plays a crucial role in determining the robust catalyst properties.

  2. The Significance of Multivalent Bonding Motifs and “Bond Order” in DNA-Directed Nanoparticle Crystallization

    Energy Technology Data Exchange (ETDEWEB)

    Thaner, Ryan V.; Eryazici, Ibrahim; Macfarlane, Robert J.; Brown, Keith A.; Lee, Byeongdu; Nguyen, SonBinh T.; Mirkin, Chad A.

    2016-05-18

    Multivalent oligonucleotide-based bonding elements have been synthesized and studied for the assembly and crystallization of gold nanoparticles. Through the use of organic branching points, divalent and trivalent DNA linkers were readily incorporated into the oligonucleotide shells that define DNA-nanoparticles and compared to monovalent linker systems. These multivalent bonding motifs enable the change of "bond strength" between particles and therefore modulate the effective "bond order." In addition, the improved accessibility of strands between neighboring particles, either due to multivalency or modifications to increase strand flexibility, gives rise to superlattices with less strain in the crystallites compared to traditional designs. Furthermore, the increased availability and number of binding modes also provide a new variable that allows previously unobserved crystal structures to be synthesized, as evidenced by the formation of a thorium phosphide superlattice.

  3. Photovoltaic mechanisms in polycrystalline thin-film solar cells. Quarterly technical progress report No. 3, April 27-July 27, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Zanio, K.

    1979-10-01

    Indium phosphide films were prepared on (100) InP substrates by the planar reactive deposition technique in the temperature range 220 to 260/sup 0/C and growth rates of about 1 ..mu..m/hr, complete single-crystal epitaxy was achieved. The onset of the single-crystal to polycrystalline transition at 245/sup 0/C is characterized by a mosaic structure. Parallel studies to eventually passivate the grain boundaries in polycrystalline films were undertaken. A 5HC1:3HNO/sub 3/:4HF etch was found to preferentially attack 90% of the grain boundaries in bulk polycrystalline InP wafers. Canyons with depths greater than 10 ..mu..m and widths less than 1 ..mu..m were the most common form of attack. Although the etch had no effect on simple twin boundaries, preferential attack was observed at interfaces formed by multiple twinning events.

  4. Metalloporphyrin-modified semiconductors for solar fuel production.

    Science.gov (United States)

    Khusnutdinova, D; Beiler, A M; Wadsworth, B L; Jacob, S I; Moore, G F

    2017-01-01

    We report a direct one-step method to chemically graft metalloporphyrins to a visible-light-absorbing gallium phosphide semiconductor with the aim of constructing an integrated photocathode for light activating chemical transformations that include capturing, converting, and storing solar energy as fuels. Structural characterization of the hybrid assemblies is achieved using surface-sensitive spectroscopic methods, and functional performance for photoinduced hydrogen production is demonstrated via three-electrode electrochemical testing combined with photoproduct analysis using gas chromatography. Measurements of the total per geometric area porphyrin surface loadings using a cobalt-porphyrin based assembly indicate a turnover frequency ≥3.9 H2 molecules per site per second, representing the highest reported to date for a molecular-catalyst-modified semiconductor photoelectrode operating at the H+/H2 equilibrium potential under 1-sun illumination.

  5. Influence of Ni-P Coated SiC and Laser Scan Speed on the Microstructure and Mechanical Properties of IN625 Metal Matrix Composites

    Science.gov (United States)

    Sateesh, N. H.; Kumar, G. C. Mohan; Krishna, Prasad

    2015-12-01

    Nickel based Inconel-625 (IN625) metal matrix composites (MMCs) were prepared using pre-heated nickel phosphide (Ni-P) coated silicon carbide (SiC) reinforcement particles by Direct Metal Laser Sintering (DMLS) additive manufacturing process under inert nitrogen atmosphere to obtain interface influences on MMCs. The distribution of SiC particles and microstructures were characterized using optical and scanning electron micrographs, and the mechanical behaviours were thoroughly examined. The results clearly reveal that the interface integrity between the SiC particles and the IN625 matrix, the mixed powders flowability, the SiC ceramic particles and laser beam interaction, and the hardness, and tensile characteristics of the DMLS processed MMCs were improved effectively by the use of Ni-P coated SiC particles.

  6. Large-scale synthesis of high quality InP quantum dots in a continuous flow-reactor under supercritical conditions.

    Science.gov (United States)

    Ippen, Christian; Schneider, Benjamin; Pries, Christopher; Kröpke, Stefan; Greco, Tonino; Holländer, Andreas

    2015-02-27

    The synthesis of indium phosphide quantum dots (QDs) in toluene under supercritical conditions was carried out in a macroscopic continuous flow reaction system. The results of first experiments are reported in comparison with analogous reactions in octadecene. The reaction system is described and details are provided about special procedures that are enabled by the continuous flow system for the screening of reaction conditions. The produced QDs show very narrow emission peaks with full width at half maximum down to 45 nm and reasonable photoluminescence quantum yields. The subsequent purification process is facilitated by the ease of removal of toluene, and the productivity of the system is increased by high temperature and high pressure conditions.

  7. Selective detection of dopamine in the presence of ascorbic acid via fluorescence quenching of InP/ZnS quantum dots.

    Science.gov (United States)

    Ankireddy, Seshadri Reddy; Kim, Jongsung

    2015-01-01

    Dopamine is a neurotransmitter of the catecholamine family and has many important roles, especially in human brain. Several diseases of the nervous system, such as Parkinson's disease, attention deficit hyperactivity disorder, restless legs syndrome, are believed to be related to deficiency of dopamine. Several studies have been performed to detect dopamine by using electrochemical analysis. In this study, quantum dots (QDs) were used as sensing media for the detection of dopamine. The surface of the QDs was modified with l-cysteine by coupling reaction to increase the selectivity of dopamine. The fluorescence of cysteine-capped indium phosphide/zinc sulfide QDs was quenched by dopamine with various concentrations in the presence of ascorbic acid. This method shows good selectivity for dopamine detection, and the detection limit was 5 nM.

  8. Enhanced monolayer MoS2/InP heterostructure solar cells by graphene quantum dots

    Science.gov (United States)

    Wang, Peng; Lin, Shisheng; Ding, Guqiao; Li, Xiaoqiang; Wu, Zhiqian; Zhang, Shengjiao; Xu, Zhijuan; Xu, Sen; Lu, Yanghua; Xu, Wenli; Zheng, Zheyang

    2016-04-01

    We demonstrate significantly improved photovoltaic response of monolayer molybdenum disulfide (MoS2)/indium phosphide (InP) van der Waals heterostructure induced by graphene quantum dots (GQDs). Raman and photoluminescence measurements indicate that effective charge transfer takes place between GQDs and MoS2, which results in n-type doping of MoS2. The doping effect increases the barrier height at the MoS2/InP heterojunction, thus the averaged power conversion efficiency of MoS2/InP solar cells is improved from 2.1% to 4.1%. The light induced doping by GQD provides a feasible way for developing more efficient MoS2 based heterostructure solar cells.

  9. Rapidly reconfigurable high-fidelity optical arbitrary waveform generation in heterogeneous photonic integrated circuits.

    Science.gov (United States)

    Feng, Shaoqi; Qin, Chuan; Shang, Kuanping; Pathak, Shibnath; Lai, Weicheng; Guan, Binbin; Clements, Matthew; Su, Tiehui; Liu, Guangyao; Lu, Hongbo; Scott, Ryan P; Ben Yoo, S J

    2017-04-17

    This paper demonstrates rapidly reconfigurable, high-fidelity optical arbitrary waveform generation (OAWG) in a heterogeneous photonic integrated circuit (PIC). The heterogeneous PIC combines advantages of high-speed indium phosphide (InP) modulators and low-loss, high-contrast silicon nitride (Si3N4) arrayed waveguide gratings (AWGs) so that high-fidelity optical waveform syntheses with rapid waveform updates are possible. The generated optical waveforms spanned a 160 GHz spectral bandwidth starting from an optical frequency comb consisting of eight comb lines separated by 20 GHz channel spacing. The Error Vector Magnitude (EVM) values of the generated waveforms were approximately 16.4%. The OAWG module can rapidly and arbitrarily reconfigure waveforms upon every pulse arriving at 2 ns repetition time. The result of this work indicates the feasibility of truly dynamic optical arbitrary waveform generation where the reconfiguration rate or the modulator bandwidth must exceed the channel spacing of the AWG and the optical frequency comb.

  10. Hybrid Nanocavity Resonant Enhancement of Color Center Emission in Diamond

    Directory of Open Access Journals (Sweden)

    Paul E. Barclay

    2011-09-01

    Full Text Available Resonantly enhanced emission from the zero-phonon line of a diamond nitrogen-vacancy (NV center in single crystal diamond is demonstrated experimentally using a hybrid whispering gallery mode nanocavity. A 900 nm diameter ring nanocavity formed from gallium phosphide, whose sidewalls extend into a diamond substrate, is tuned onto resonance at a low temperature with the zero-phonon line of a negatively charged NV center implanted near the diamond surface. When the nanocavity is on resonance, the zero-phonon line intensity is enhanced by approximately an order of magnitude, and the spontaneous emission lifetime of the NV is reduced by as much as 18%, corresponding to a 6.3X enhancement of emission in the zero photon line.

  11. Photocatalytic reduction of CO2 on TiO2 and other semiconductors.

    Science.gov (United States)

    Habisreutinger, Severin N; Schmidt-Mende, Lukas; Stolarczyk, Jacek K

    2013-07-15

    Rising atmospheric levels of carbon dioxide and the depletion of fossil fuel reserves raise serious concerns about the ensuing effects on the global climate and future energy supply. Utilizing the abundant solar energy to convert CO2 into fuels such as methane or methanol could address both problems simultaneously as well as provide a convenient means of energy storage. In this Review, current approaches for the heterogeneous photocatalytic reduction of CO2 on TiO2 and other metal oxide, oxynitride, sulfide, and phosphide semiconductors are presented. Research in this field is focused primarily on the development of novel nanostructured photocatalytic materials and on the investigation of the mechanism of the process, from light absorption through charge separation and transport to CO2 reduction pathways. The measures used to quantify the efficiency of the process are also discussed in detail. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Self-referenced octave-wide subharmonic GaP optical parametric oscillator centered at 3  μm and pumped by an Er-fiber laser.

    Science.gov (United States)

    Ru, Qitian; Loparo, Zachary E; Zhang, XiaoSheng; Crystal, Sean; Vasu, Subith; Schunemann, Peter G; Vodopyanov, Konstantin L

    2017-11-15

    We report an octave-wide mid-IR spectrum (2.3-4.8 μm) obtained from a subharmonic optical parametric oscillator (OPO) based on a newly developed nonlinear crystal, orientation-patterned gallium phosphide (OP-GaP), which was synchronously pumped by a femtosecond 1560 nm fiber laser. We proved that the octave-wide output is in the form of a single frequency comb. The observed f-to-2f frequency beats, originating directly from the OPO, can be used for self-referencing and phase locking of the pump laser comb with no need for supercontinuum generation. With an average output power of ∼30  mW, this setup might be beneficial for a variety of spectroscopic applications in the mid-IR.

  13. Ligand influence on the formation of P/Se semiconductor materials from metal-organic complexes.

    Science.gov (United States)

    Panneerselvam, Arunkumar; Nguyen, Chinh Q; Waters, John; Malik, Mohammad A; O'Brien, Paul; Raftery, James; Helliwell, Madeleine

    2008-09-07

    The complexes [Ni{(SeP(i)Pr(2))(2)N}(2)] (2), [Ni(Se(2)P(i)Pr(2))(2)] (), and [Co(Se(2)P(i)Pr(2))(2)] (4) were synthesised and the X-ray single crystal structures of (1) and (2) were determined. Thin films of nickel selenide, cobalt selenide and cobalt phosphide have been deposited by the chemical vapour deposition method using imidodiselenophosphinato-nickel(ii) (1), -cobalt(ii) [Co{(SeP(i)Pr(2))(2)N}(2)] (3), diselenophosphinato-nickel(ii) (2), -cobalt(ii) (4) and diselenocarbamato-nickel(ii) [Ni(Se(2)CNEt(2))(2)] (5), and -cobalt(iii) [Co(Se(2)CNEt(2))(3)] (6) precursors.

  14. Optical properties of nanowire metamaterials with gain

    DEFF Research Database (Denmark)

    Isidio de Lima, Joaquim Junior; Adam, Jost; Rego, Davi

    2016-01-01

    The transmittance, reflectance and absorption of a nanowire metamaterial with optical gain are numerically simulated and investigated. It is assumed that the metamaterial is represented by aligned silver nanowires embedded into a semiconductor matrix, made of either silicon or gallium phosphide....... The gain in the matrix is modeled by adding a negative imaginary part to the dielectric function of the semiconductor. It is found that the optical coefficients of the metamaterial depend on the gain magnitude in a non-trivial way: they can both increase and decrease with gain depending on the lattice...... constant of the metamaterial. This peculiar behavior is explained by the field redistribution between the lossy metal nanowires and the amplifying matrix material. These findings are significant for a proper design of nanowire metamaterials with low optical losses for diverse applications....

  15. Petrography of the carbonaceous, diamond-bearing stone "Hypatia" from southwest Egypt: A contribution to the debate on its origin

    Science.gov (United States)

    Belyanin, Georgy A.; Kramers, Jan D.; Andreoli, Marco A. G.; Greco, Francesco; Gucsik, Arnold; Makhubela, Tebogo V.; Przybylowicz, Wojciech J.; Wiedenbeck, Michael

    2018-02-01

    The stone named "Hypatia" found in the Libyan Desert Glass area of southwest Egypt is carbon-dominated and rich in microdiamonds. Previous noble gas and nitrogen isotope studies suggest an extraterrestrial origin. We report on a reconnaissance study of the carbonaceous matrix of this stone and the phases enclosed in it. This focused on areas not affected by numerous transecting fractures mostly filled with secondary minerals. The work employed scanning electron microscopy (SEM) with energy-dispersive (EDS) and wavelength-dispersive (WDS) electron microprobe (EMPA) analysis, Proton Induced X-ray Emission (PIXE) spectrometry and micro-Raman spectroscopy. We found that carbonaceous matrices of two types occur irregularly intermingled on the 50-500 μm scale: Matrix-1, consisting of almost pure carbonaceous matter, and Matrix-2, containing Fe, Ni, P and S at abundances analyzable by microprobe. Matrix-2 contains the following phases as inclusions: (i) (Fe,Ni) sulphide occurring in cloud-like concentrations of sub-μm grains, in domains of the matrix that are enriched in Fe and S. These domains have (Fe + Ni)/S (atomic) = 1.51 ± 0.24 and Ni/Fe = 0.086 ± 0.061 (both 1SD); (ii) grains up to ∼5 μm in size of moissanite (SiC); (iii) Ni-phosphide compound grains up to 60 μm across that appear cryptocrystalline or amorphous and have (Ni + Fe)/P (atomic) = 5.6. ± 1.7 and Ni/Fe = 74 ± 29 (both 1SD), where both these ratios are much higher than any known Ni-phosphide minerals; (iv) rare grains (observed only once) of graphite, metallic Al, Fe and Ag, and a phase consisting of Ag, P and I. In Matrix-2, Raman spectroscopy shows a prominent narrow diamond band at 1340 cm-1. In Matrix-1 the D and G bands of disordered carbon are dominant, but a minor diamond band is ubiquitous, accounting for the uniform hardness of the material. The D and G bands have average full width at half maximum (FWHM) values of 295 ± 19 and 115 ± 19 cm-1, respectively, and the D/G intensity ratio

  16. Annealing furnace for III-V semiconductor devices

    Science.gov (United States)

    O'Connor, J. M.; Hier, H. S.; Ketchum, R. M.

    1986-02-01

    A furnace for annealing ion implantation damage in III-V semiconductors has been built and tested. Designed for research applications, the furnace can accommodate odd shapes of material up to 2 in. in diameter. Samples are loaded onto a novel cantilevered support and are not moved during the annealing operation, facilitating proximity annealing techniques. Both chambers of this dual chambered system are O-ring sealed for added safety during annealing in an arsine gas ambient. Electron mobilities between 4400 and 4600 cm2/V s at 300 K are routinely measured for 2×1017 cm-3 gallium arsenide material annealed in this sytem. The system has been used to anneal indium phosphide as well as gallium arsenide wafers.

  17. Properties and potential optoelectronic applications of lead halide perovskite nanocrystals

    Science.gov (United States)

    Kovalenko, Maksym V.; Protesescu, Loredana; Bodnarchuk, Maryna I.

    2017-11-01

    Semiconducting lead halide perovskites (LHPs) have not only become prominent thin-film absorber materials in photovoltaics but have also proven to be disruptive in the field of colloidal semiconductor nanocrystals (NCs). The most important feature of LHP NCs is their so-called defect-tolerance—the apparently benign nature of structural defects, highly abundant in these compounds, with respect to optical and electronic properties. Here, we review the important differences that exist in the chemistry and physics of LHP NCs as compared with more conventional, tetrahedrally bonded, elemental, and binary semiconductor NCs (such as silicon, germanium, cadmium selenide, gallium arsenide, and indium phosphide). We survey the prospects of LHP NCs for optoelectronic applications such as in television displays, light-emitting devices, and solar cells, emphasizing the practical hurdles that remain to be overcome.

  18. Cellular uptake of conjugated InP quantum dots

    Science.gov (United States)

    Chibli, Hicham; Carlini, Lina; Ntumba, Kalonji; Nadeau, Jay

    2010-02-01

    Indium phosphide (InP) nanocrystals show similar absorbance and emission spectra to CdTe quantum dots, but unlike particles containing cadmium, may potentially be used in in vivo applications. However, the particles are more challenging to make water-soluble, show broader emission spectra than most quantum dots, and their behavior in living cells is largely unknown. In this work we solubilize InP nanocrystals with simple thiols (mercaptopropionic acid) and conjugate them to the neurotransmitter dopamine or the protein transferrin. Degree of uptake and labeling patterns of QDs alone, QD-dopamine, and QD-transferrin are compared in different cell lines and toxicity is evaluated using the sulforhodamine B (SRB) assay.

  19. The Role of III-V Substrate Roughness and Deoxidation Induced by Digital Etch in Achieving Low Resistance Metal Contacts

    Directory of Open Access Journals (Sweden)

    Florent Ravaux

    2017-06-01

    Full Text Available To achieve low contact resistance between metal and III-V material, transmission-line-model (TLM structures of molybdenum (Mo were fabricated on indium phosphide (InP substrate on the top of an indium gallium arsenide (InGaAs layer grown by molecular beam epitaxy. The contact layer was prepared using a digital etch procedure before metal deposition. The contact resistivity was found to decrease significantly with the cleaning process. High Resolution Transmission & Scanning Electron Microscopy (HRTEM & HRSTEM investigations revealed that the surface roughness of treated samples was increased. Further analysis of the metal-semiconductor interface using Energy Electron Loss Spectroscopy (EELS showed that the amount of oxides (InxOy, GaxOy or AsxOy was significantly decreased for the etched samples. These results suggest that the low contact resistance obtained after digital etching is attributed to the combined effects of the induced surface roughness and oxides removal during the digital etch process.

  20. Extraction of second harmonic from the In0.53Ga0.47As planar Gunn diode using radial stub resonators

    Science.gov (United States)

    Maricar, Mohamed Ismaeel; Khalid, A.; Glover, J.; Evans, G. A.; Vasileious, P.; Li, Chong; Cumming, D.; Oxley, C. H.

    2014-09-01

    Planar Indium Gallium Arsenide (InGaAs) Gunn diodes with on chip matching circuits have been fabricated on a semi-insulating Indium Phosphide (InP) substrate to enable the extraction of the second harmonic in millimeter-wave and terahertz frequencies. The planar Gunn diodes were designed in coplanar waveguide (CPW) format with an active channel length of 4 μm and width 120 μm integrated to CPW matching circuit and radial stub resonator to suppress the fundamental and to extract the second harmonic. The initial experimental measurements have given a second harmonic signal at 118 GHz with an output power of -20 dBm and the fundamental signal at 59 GHz was suppressed to the noise level of the experimental set-up.

  1. Brazing method

    Science.gov (United States)

    McCormick, James T.; Ferry, Paul B.; Hall, John C.

    1981-10-06

    There is disclosed a positive cathode electrode structure formed by brazing a thin porous membrane to a backing material by preselecting a predetermined area of the thin porous membrane and thereafter providing a braze flow barrier throughout the remainder of the membrane and electrolessly plating a nickel-phosphide alloy on the backing material, or in this case the honeycomb structure. The preselected area of the thin porous membrane is placed in intimate contact with the electrolessly plated portion of the backing material and heated to elevated temperatures in the absence of oxygen to form a brazed joint limited to a preselected area. If the braze flow barrier is provided by application of a liquid organic solvent, then the organic solvent is driven off by maintaining the thin porous membrane at elevated temperatures for an extended period of time prior to the brazing operation.

  2. Efficient Water Electrolysis Using Ni2P as a Bifunctional Catalyst: Unveiling the Oxygen Evolution Catalytic Properties of Ni2P.

    Science.gov (United States)

    Stern, Lucas-Alexandre; Hu, Xile

    2016-01-01

    The excellent bifunctional catalytic activity of nickel phosphide (Ni2P) for water splitting is reported. Ni2P, an active hydrogen evolving catalyst, is shown to be highly active for oxygen evolution. Only 290 mV of overpotential is required to generate a current density of 10 mA cm(-2) in 1 M KOH. Under oxygen evolving conditions, Ni2P undergoes structural modification to form a Ni2P/NiOx core-shell assembly, the catalytic active species. Ni2P is applied on both electrodes of an alkaline electrolyser and a current density of 10 mA cm(-2) is generated at 1.63 V.

  3. Mapping Local Charge Recombination Heterogeneity by Multidimensional Nanospectroscopic Imaging

    Science.gov (United States)

    Bao, Wei; Melli, M.; Caselli, N.; Riboli, F.; Wiersma, D. S.; Staffaroni, M.; Choo, H.; Ogletree, D. F.; Aloni, S.; Bokor, J.; Cabrini, S.; Intonti, F.; Salmeron, M. B.; Yablonovitch, E.; Schuck, P. J.; Weber-Bargioni, A.

    2012-12-01

    As materials functionality becomes more dependent on local physical and electronic properties, the importance of optically probing matter with true nanoscale spatial resolution has increased. In this work, we mapped the influence of local trap states within individual nanowires on carrier recombination with deeply subwavelength resolution. This is achieved using multidimensional nanospectroscopic imaging based on a nano-optical device. Placed at the end of a scan probe, the device delivers optimal near-field properties, including highly efficient far-field to near-field coupling, ultralarge field enhancement, nearly background-free imaging, independence from sample requirements, and broadband operation. We performed ~40-nanometer-resolution hyperspectral imaging of indium phosphide nanowires via excitation and collection through the probes, revealing optoelectronic structure along individual nanowires that is not accessible with other methods.

  4. Aerogels Handbook

    CERN Document Server

    Aegerter, Michel A; Koebel, Matthias M

    2011-01-01

    Aerogels are the lightest solids known. Up to 1000 times lighter than glass and with a density as low as only four times that of air, they show very high thermal, electrical and acoustic insulation values and hold many entries in Guinness World Records. Originally based on silica, R&D efforts have extended this class of materials to non-silicate inorganic oxides, natural and synthetic organic polymers, carbon, metal and ceramic materials, etc. Composite systems involving polymer-crosslinked aerogels and interpenetrating hybrid networks have been developed and exhibit remarkable mechanical strength and flexibility. Even more exotic aerogels based on clays, chalcogenides, phosphides, quantum dots, and biopolymers such as chitosan are opening new applications for the construction, transportation, energy, defense and healthcare industries. Applications in electronics, chemistry, mechanics, engineering, energy production and storage, sensors, medicine, nanotechnology, military and aerospace, oil and gas recove...

  5. Nanocrystal doped matrixes

    Science.gov (United States)

    Parce, J. Wallace; Bernatis, Paul; Dubrow, Robert; Freeman, William P.; Gamoras, Joel; Kan, Shihai; Meisel, Andreas; Qian, Baixin; Whiteford, Jeffery A.; Ziebarth, Jonathan

    2010-01-12

    Matrixes doped with semiconductor nanocrystals are provided. In certain embodiments, the semiconductor nanocrystals have a size and composition such that they absorb or emit light at particular wavelengths. The nanocrystals can comprise ligands that allow for mixing with various matrix materials, including polymers, such that a minimal portion of light is scattered by the matrixes. The matrixes of the present invention can also be utilized in refractive index matching applications. In other embodiments, semiconductor nanocrystals are embedded within matrixes to form a nanocrystal density gradient, thereby creating an effective refractive index gradient. The matrixes of the present invention can also be used as filters and antireflective coatings on optical devices and as down-converting layers. Processes for producing matrixes comprising semiconductor nanocrystals are also provided. Nanostructures having high quantum efficiency, small size, and/or a narrow size distribution are also described, as are methods of producing indium phosphide nanostructures and core-shell nanostructures with Group II-VI shells.

  6. Highly nonlinear polarization-maintaining photonic crystal fiber with nanoscale GaP strips.

    Science.gov (United States)

    Amin, Md Nafiz; Faisal, Mohammad

    2016-12-10

    A highly birefringent silica photonic crystal fiber (PCF) is proposed with nanoscale gallium phosphide strips at the core and modified spiral cladding air hole distribution. Optical properties of the PCF are simulated using the finite element method. Significant influences of low-refractive-index slot region confinement and high-index strips confinement are observed for two different modes. This introduces a high birefringence of ∼0.58 at 1.55 μm wavelength. Moreover, a high nonlinearity coefficient of the order of ∼104  W-1  km-1 is achieved in the wavelength range from 1.4 to 1.7 μm. The proposed fiber will find promising applications in coherent optical communications and sensing applications.

  7. Effect of Deposition Time on the Morphological Features and Corrosion Resistance of Electroless Ni-High P Coatings on Aluminium

    Directory of Open Access Journals (Sweden)

    N. Sridhar

    2013-01-01

    Full Text Available High phosphorus Ni-P alloy was deposited on aluminium substrate using electroless deposition route. Using zincating bath, the surface was activated before deposition. Deposition time was varied from 15 minutes to 3 hours. Deposit was characterised using scanning electron microscope with energy dispersive spectroscope, X-ray diffraction, and microhardness tester. The corrosion resistance was measured using Tafel extrapolation route. The medium was aqueous 5% HNO3 solution. The analysis showed that the deposit consisted of nodules of submicron and micron scale. The predominant phase in the deposit was nickel along with phosphides of nickel. Compared to substrate material, deposit showed higher hardness. With increase in deposition time, the deposit showed more nobleness in 5% HNO3 solution and nobleness reached a limiting value in 1 hour deposition time.

  8. Fibre optic communication key devices

    CERN Document Server

    Grote, Norbert

    2017-01-01

    The book gives an in-depth description of key devices of current and next generation fibre optic communication networks. Devices treated include semiconductor lasers, optical amplifiers, modulators, wavelength filters and other passives, detectors, all-optical switches, but relevant properties of optical fibres and network aspects are included as well. The presentations include the physical principles underlying the various devices, technologies used for their realization, typical performance characteristics and limitations, but development trends towards more advanced components are also illustrated. This new edition of a successful book was expanded and updated extensively. The new edition covers among others lasers for optical communication, optical switches, hybrid integration, monolithic integration and silicon photonics. The main focus is on Indium phosphide-based structures but silicon photonics is included as well. The book covers relevant principles, state-of-the-art implementations, status of curren...

  9. Tuning the electronic and optical properties of XP(X = Al,Ga) monolayer semiconductors using biaxial strain effect: Modified Becke-Johnson calculations

    Science.gov (United States)

    Akbari, Ahmad; Naseri, Mosayeb; Jalilian, Jaafar

    2018-01-01

    In this paper, based on full potential density functional theory calculations, the electronic and optical properties of aluminium and gallium phosphide (AlP and GaP) graphene-like structures are investigated under different biaxial compressive and tensile strain loads. One of the fascinating properties of these new monolayers is their high stretch-ability and high mechanosensitivity of their electronic and optical features. The electronic calculations display that the energy gap of materials versus the exerted strain can be estimated by a second order polynomial equation. Furthermore, the optical calculations indicate that the electronic and optical gap of AlP and GaP monolayers can be tuned by biaxial strain loads.

  10. Photo-electrochemical formation of porous GaP

    Energy Technology Data Exchange (ETDEWEB)

    Ricci, P.C.; Anedda, A.; Carbonaro, C.M.; Chiriu, D.; Clemente, F.; Corpino, R. [Dipartimento di Fisica, Universita degli Studi di Cagliari and INFM UdR-CA, sp n 8, Km 0.700, 09042 Monserrato Cagliari (Italy)

    2005-06-01

    Electrochemical etching formation mechanisms of porous gallium phosphide are investigated under different conditions. Anodic etching of single crystalline n-type GaP was performed in H{sub 2}SO{sub 4} 0.5 M aqueous solution both under dark condition and by shining the samples with the 351 nm line of an Argon laser. Different reaction mechanisms are found as evidenced by the analysis of the current-voltage characteristics. Moreover, a dependence of the porosity on the laser power density is detected. A quantitative estimate of the porosity is given by studying the Froehlich modes through micro Raman Spectroscopy. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. A novel and compact nanoindentation device for in situ nanoindentation tests inside the scanning electron microscope

    Directory of Open Access Journals (Sweden)

    Hu Huang

    2012-03-01

    Full Text Available In situ nanomechanical tests provide a unique insight into mechanical behaviors of materials, such as fracture onset and crack propagation, shear band formation and so on. This paper presents a novel in situ nanoindentation device with dimensions of 103mm×74mm×60mm. Integrating the stepper motor, the piezoelectric actuator and the flexure hinge, the device can realize coarse adjustment of the specimen and precision loading and unloading of the indenter automatically. A novel indenter holder was designed to guarantee that the indenter penetrates into and withdraws from the specimen surface vertically. Closed-loop control of the indentation process was established to solve the problem of nonlinearity of the piezoelectric actuator and to enrich the loading modes. The in situ indentation test of Indium Phosphide (InP inside the scanning electron microscope (SEM was carried out and the experimental result indicates the feasibility of the developed device.

  12. Chip-based quantum key distribution

    Science.gov (United States)

    Sibson, P.; Erven, C.; Godfrey, M.; Miki, S.; Yamashita, T.; Fujiwara, M.; Sasaki, M.; Terai, H.; Tanner, M. G.; Natarajan, C. M.; Hadfield, R. H.; O'Brien, J. L.; Thompson, M. G.

    2017-01-01

    Improvement in secure transmission of information is an urgent need for governments, corporations and individuals. Quantum key distribution (QKD) promises security based on the laws of physics and has rapidly grown from proof-of-concept to robust demonstrations and deployment of commercial systems. Despite these advances, QKD has not been widely adopted, and large-scale deployment will likely require chip-based devices for improved performance, miniaturization and enhanced functionality. Here we report low error rate, GHz clocked QKD operation of an indium phosphide transmitter chip and a silicon oxynitride receiver chip—monolithically integrated devices using components and manufacturing processes from the telecommunications industry. We use the reconfigurability of these devices to demonstrate three prominent QKD protocols—BB84, Coherent One Way and Differential Phase Shift—with performance comparable to state-of-the-art. These devices, when combined with integrated single photon detectors, pave the way for successfully integrating QKD into future telecommunications networks. PMID:28181489

  13. Nanoarchitectured Design of Porous Materials and Nanocomposites from Metal-Organic Frameworks.

    Science.gov (United States)

    Kaneti, Yusuf Valentino; Tang, Jing; Salunkhe, Rahul R; Jiang, Xuchuan; Yu, Aibing; Wu, Kevin C-W; Yamauchi, Yusuke

    2017-03-01

    The emergence of metal-organic frameworks (MOFs) as a new class of crystalline porous materials is attracting considerable attention in many fields such as catalysis, energy storage and conversion, sensors, and environmental remediation due to their controllable composition, structure and pore size. MOFs are versatile precursors for the preparation of various forms of nanomaterials as well as new multifunctional nanocomposites/hybrids, which exhibit superior functional properties compared to the individual components assembling the composites. This review provides an overview of recent developments achieved in the fabrication of porous MOF-derived nanostructures including carbons, metal oxides, metal chalcogenides (metal sulfides and selenides), metal carbides, metal phosphides and their composites. Finally, the challenges and future trends and prospects associated with the development of MOF-derived nanomaterials are also examined. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Phase-controlled synthesis of polymorphic tungsten diphosphide with hybridization of monoclinic and orthorhombic phases as a novel electrocatalyst for efficient hydrogen evolution

    Science.gov (United States)

    Pi, Mingyu; Wu, Tianli; Guo, Weimeng; Wang, Xiaodeng; Zhang, Dingke; Wang, Shuxia; Chen, Shijian

    2017-05-01

    The design and development of high-efficiency and non-noble-metal hydrogen evolution reaction (HER) electrocatalysts for future clean and renewable energy system has excited significant research interests over the recent years. In this communication, the polymorphic tungsten diphosphide (p-WP2) nanoparticles with mixed monoclinic (α-) and orthorhombic (β-) phases are synthesized by phase-controlled phosphidation route via vacuum capsulation and explored as a novel efficient electrocatalyst towards HER. The p-WP2 catalyst delivers superior performance with excellent stability under both acidic and alkaline conditions over its single phases of α-WP2 and β-WP2. This finding demonstrates that a highly efficient hybrid electrocatalyst can be achieved via precise composition controlling and may open up exciting opportunities for their practical applications toward energy conversion.

  15. Optimal radii of photonic crystal holes within DBR mirrors in long wavelength VCSEL.

    Science.gov (United States)

    Czyszanowski, Tomasz; Dems, Maciej; Thienpont, Hugo; Panajotov, Krassimir

    2007-02-05

    The modal characteristics of a Photonic-Crystal Vertical-Cavity Surface-Emitting diode Laser (PC-VCSEL) have been investigated. Photonic crystal structure, realized by a regular net of air holes within the layers, has been etched in the upper DBR mirror. An advanced three-dimensional, vectorial electromagnetic model has been applied to a phosphide - based device design featuring InGaAlAs active region, AlGaAs/GaAs mirrors and a tunnel junction to confine the current flow. For the structure under consideration a single mode operation has been found for the hole diameter over photonic crystal lattice constant ratio between 0.1 - 0.3.

  16. High-sweep-rate 1310 nm MEMS-VCSEL with 150 nm continuous tuning range.

    Science.gov (United States)

    Jayaraman, V; Cole, G D; Robertson, M; Uddin, A; Cable, A

    2012-07-05

    Microelectromechanical-systems-based vertical-cavity surface-emitting lasers (MEMS-VCSELs) capable of a 150 nm continuous tuning range near 1310 nm are demonstrated. These devices employ a thin optically pumped active region structure with large free-spectral range, which promotes wide and continuous tuning. To achieve VCSEL emission at 1310 nm, a wide-gain-bandwidth indium phosphide-based multiple quantum well active region is combined with a wide-bandwidth fully oxidised GaAs-based mirror through wafer bonding, with tuning enabled by a suspended dielectric top mirror. These devices are capable of being scanned over the entire tuning range at frequencies up to 500 kHz, making them ideal for applications such as swept source optical coherence tomography and high-speed transient spectroscopy.

  17. An effective Pd-Ni(2)P/C anode catalyst for direct formic acid fuel cells.

    Science.gov (United States)

    Chang, Jinfa; Feng, Ligang; Liu, Changpeng; Xing, Wei; Hu, Xile

    2014-01-03

    The direct formic acid fuel cell is an emerging energy conversion device for which palladium is considered as the state-of-the-art anode catalyst. In this communication, we show that the activity and stability of palladium for formic acid oxidation can be significantly enhanced using nickel phosphide (Ni(2)P) nanoparticles as a cocatalyst. X-ray photoelectron spectroscopy (XPS) reveals a strong electronic interaction between Ni(2)P and Pd. A direct formic acid fuel cell incorporating the best Pd–Ni(2)P anode catalyst exhibits a power density of 550 mWcm(-2), which is 3.5 times of that of an analogous device using a commercial Pd anode catalyst.

  18. Mg-containing hydroxyapatite coatings produced by plasma electrolytic oxidation of titanium

    Energy Technology Data Exchange (ETDEWEB)

    Antonio, Cesar Augusto; Rangel, Elidiane Cipriano; Durrant, Steven Frederick; Cruz, Nilson Cristino da, E-mail: cesar.augustoa@hotmail.com [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sorocaba, SP (Brazil). Lab. de Plasmas Tecnologicos; Delgado-Silva, Adriana de Oliveira [Universidade Federal de Sao Carlos (UFSCar), Sorocaba, SP (Brazil); Tabacniks, Manfredo H. [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica

    2017-07-15

    Plasma Electrolytic Oxidation (PEO) is promising for the processing of biomaterials because it enables the production of surfaces with adjustable composition and structure. In this work, aimed at the improvement of the bioactivity of titanium, PEO has been used to grow calcium phosphide coatings on titanium substrates. The effects of the addition of magnesium acetate to the electrolytes on the composition of the coatings produced during 120 s on Ti disks using bipolar voltage pulses and solutions of calcium and magnesium acetates and sodium glycerophosphate as electrolytes have been studied. Scanning electron microscopy, X-ray energy dispersive spectroscopy, Rutherford backscattering spectroscopy, X-ray diffractometry with Rietveld refinement and profilometry were used to characterize the modified samples. Coatings composed of nearly 50 % of Mg-doped hydroxyapatite have been produced. In certain conditions up to 4% Mg can be incorporated into the coating without any observable significant structural modifications of the hydroxyapatite. (author)

  19. Chip-based quantum key distribution.

    Science.gov (United States)

    Sibson, P; Erven, C; Godfrey, M; Miki, S; Yamashita, T; Fujiwara, M; Sasaki, M; Terai, H; Tanner, M G; Natarajan, C M; Hadfield, R H; O'Brien, J L; Thompson, M G

    2017-02-09

    Improvement in secure transmission of information is an urgent need for governments, corporations and individuals. Quantum key distribution (QKD) promises security based on the laws of physics and has rapidly grown from proof-of-concept to robust demonstrations and deployment of commercial systems. Despite these advances, QKD has not been widely adopted, and large-scale deployment will likely require chip-based devices for improved performance, miniaturization and enhanced functionality. Here we report low error rate, GHz clocked QKD operation of an indium phosphide transmitter chip and a silicon oxynitride receiver chip-monolithically integrated devices using components and manufacturing processes from the telecommunications industry. We use the reconfigurability of these devices to demonstrate three prominent QKD protocols-BB84, Coherent One Way and Differential Phase Shift-with performance comparable to state-of-the-art. These devices, when combined with integrated single photon detectors, pave the way for successfully integrating QKD into future telecommunications networks.

  20. First-principles study on mechanical and elastic properties of BxAl1-xP alloys

    Directory of Open Access Journals (Sweden)

    Huihui Ma

    2017-06-01

    Full Text Available Based on density functional theory calculations, systematic calculations of the structural properties, elastic anisotropy and mechanical properties of boron alloying aluminum phosphide (BxAl1-xP ternary mixed crystal have been presented. The results of the lattice parameters, band gaps, elastic constants and elastic modulus accord with the experimental and others published data well. The band structure which is described by CASTEP method indicates they are direct gap semiconductors for the composition x = 0.25, 0.50 and 0.75. Beyond that, we studied the Debye temperatures together with the acoustic velocities for all the BxAl1-xP alloys using the obtained elastic modulus. Finally, we depicted the three dimensional surface constructions to explain the elastic anisotropy using several calculated different anisotropic indexes in our work.